U.S. patent application number 13/606470 was filed with the patent office on 2013-03-14 for protein-containing adhesives, and manufacture and use thereof.
The applicant listed for this patent is Joseph J. Marcinko, Anthony A. Parker. Invention is credited to Joseph J. Marcinko, Anthony A. Parker.
Application Number | 20130065012 13/606470 |
Document ID | / |
Family ID | 47830078 |
Filed Date | 2013-03-14 |
United States Patent
Application |
20130065012 |
Kind Code |
A1 |
Parker; Anthony A. ; et
al. |
March 14, 2013 |
PROTEIN-CONTAINING ADHESIVES, AND MANUFACTURE AND USE THEREOF
Abstract
The invention provides protein adhesives and methods of making
and using such adhesives. One type of protein adhesive described
herein contains lignin and ground plant meal or an isolated
polypeptide composition obtained from plant biomass. Other types of
protein adhesives described herein contain a plant protein
composition and either a hydroxyaromatic/aldehyde, urea/aldehyde,
or amine/aldehyde component.
Inventors: |
Parker; Anthony A.;
(Newtown, PA) ; Marcinko; Joseph J.; (West
Deptford, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Parker; Anthony A.
Marcinko; Joseph J. |
Newtown
West Deptford |
PA
NJ |
US
US |
|
|
Family ID: |
47830078 |
Appl. No.: |
13/606470 |
Filed: |
September 7, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61532832 |
Sep 9, 2011 |
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61567769 |
Dec 7, 2011 |
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Current U.S.
Class: |
428/106 ;
106/155.1; 106/155.21; 106/156.3; 106/156.4; 156/336; 428/435;
428/478.2; 428/478.4 |
Current CPC
Class: |
Y10T 428/24066 20150115;
C09J 189/00 20130101; B32B 37/06 20130101; Y10T 428/31768 20150401;
B32B 7/12 20130101; B32B 37/10 20130101; C09J 197/005 20130101;
B27N 3/04 20130101; B32B 2305/72 20130101; C08L 97/005 20130101;
Y10T 428/31623 20150401; Y10T 428/31772 20150401; B32B 37/12
20130101; B32B 21/13 20130101; C08L 89/00 20130101; B32B 21/14
20130101; C09J 189/00 20130101; C08L 97/005 20130101; C09J 197/005
20130101; C08L 89/00 20130101 |
Class at
Publication: |
428/106 ;
106/156.4; 106/156.3; 106/155.21; 106/155.1; 156/336; 428/478.2;
428/478.4; 428/435 |
International
Class: |
C09J 189/00 20060101
C09J189/00; B32B 27/34 20060101 B32B027/34; B32B 21/14 20060101
B32B021/14; B32B 5/12 20060101 B32B005/12; B32B 21/00 20060101
B32B021/00; B32B 37/12 20060101 B32B037/12; B32B 23/04 20060101
B32B023/04 |
Claims
1. An adhesive composition comprising: (a) lignin; and (b) a plant
protein composition.
2-34. (canceled)
35. A hydroxyaromatic-aldehyde adhesive composition comprising: (a)
a hydroxyaromatic compound; (b) an aldehyde source; and (c) a plant
protein composition selected from the group consisting of ground
plant meal and isolated polypeptide composition.
36. The composition of claim 35, wherein the hydroxyaromatic
compound is phenol.
37. A urea compound-aldehyde adhesive composition comprising: (a) a
urea compound; (b) an aldehyde source; and (c) a plant protein
composition selected from the group consisting of ground plant meal
and isolated polypeptide composition.
38. (canceled)
39. An amine compound-aldehyde adhesive composition comprising: (a)
an amine compound selected from the group consisting of a primary
amine compound and a secondary amine compound; (b) an aldehyde
source; and (c) a plant protein composition selected from the group
consisting of ground plant meal and isolated polypeptide
composition.
40-44. (canceled)
45. The composition of claim 36, wherein the aldehyde source is
formaldehyde, acetaldehyde, glyoxal, methyl glyoxal, glycoaldehyde,
propanedial, propionaldehyde, butyraldehyde, pentanal, hexanal,
dodecanal, octadecanal, cinnamaldehyde, furfuraldehyde,
benzaldehyde, or glutaraldehyde.
46. The composition of claim 36, wherein the aldehyde source is
HC(O)H.
47. The composition of claim 36, wherein the plant protein
composition is derived from corn, wheat, sunflower, cotton,
rapeseed, canola, castor, soy, camelina, flax, jatropha, mallow,
peanuts, algae, sugarcane begasse, tobacco, whey, or a combination
thereof.
48. The composition of claim 47, wherein the plant protein
composition is ground plant meal.
49. The composition of claim 48, wherein the ground plant meal has
a particle size in the range of from about 1 .mu.m to about 200
.mu.m.
50. The composition of claim 47, wherein the plant protein
composition is isolated polypeptide composition.
51. The composition of claim 50, wherein the isolated polypeptide
composition is water-insoluble/water dispersible protein
fraction.
52. The composition of claim 50, wherein the isolated polypeptide
composition comprises one or more of the following features: (a) an
amide-I absorption band between about 1620 cm.sup.-1 and 1632
cm.sup.-1 and an amide-II band between approximately 1514 cm.sup.-1
and 1521 cm.sup.-1, as determined by solid state Fourier Transform
Infrared Spectroscopy (FTIR), (b) a prominent 2.degree. amide N--H
stretch absorption band centered at about 3272 cm.sup.-1, as
determined by solid state FTIR, (c) an average molecular weight of
between about 600 and about 2,500 Daltons, (d) two protonated
nitrogen clusters defined by .sup.15N chemical shift boundaries at
about 86.2 ppm and about 87.3 ppm, and .sup.1H chemical shift
boundaries at about 7.14 ppm and 7.29 ppm for the first cluster,
and .sup.1H chemical shift boundaries at about 6.66 ppm and 6.81
ppm for the second cluster, as determined by solution state,
two-dimensional proton-nitrogen coupled NMR, and (e) is capable of
dispersing an oil-in-water or water-in-oil to produce a homogeneous
emulsion that is stable for least 5 minutes.
53-58. (canceled)
59. The composition of claim 36, further comprising a reactive
prepolymer.
60. The composition of claim 59, wherein the reactive prepolymer is
an organic polyisocyanate.
61. The composition of claim 59, wherein the reactive prepolymer is
polymeric diphenylmethane diisocyanate.
62-63. (canceled)
64. A solid binder composition formed by curing a composition of
claim 35.
65. A method of bonding a first article to a second article
comprising: (a) depositing on a surface of the first article the
adhesive composition of claim 35 thereby to create a binding area;
and (b) contacting the binding surface with a surface of the second
article thereby to bond the first article to the second
article.
66. (canceled)
67. A method of producing a composite material comprising: (a)
combining a first article and a second article with the adhesive
composition of claim 35 to produce a mixture; and (b) curing the
mixture produced by step (a) to produce the composite material.
68-71. (canceled)
72. An article comprising two or more components bonded together
using the adhesive composition of claim 35.
73-74. (canceled)
75. An article produced using the adhesive composition of claim
35.
76. The article of claim 75, wherein the article is a
composite.
77-82. (canceled)
83. A phenol-formaldehyde-plant protein adhesive composition
comprising: (a) phenol; (b) formaldehyde; (c) a plant protein
composition selected from the group consisting of ground plant meal
and isolated polypeptide composition; and (d) a reactive
prepolymer; wherein the ratio of (i) weight percent of reactive
prepolymer in the adhesive composition to (ii) the sum of the
weight percent of phenol and formaldehyde in the adhesive
composition is greater than 1:1.
84. (canceled)
85. The composition of claim 83, wherein the ratio of (i) weight
percent of reactive prepolymer in the adhesive composition to (ii)
weight percent plant protein composition in the adhesive
composition is in the range of about 4:1 to about 1:4.
86. The composition of claim 83, further comprising water.
87. The composition of claim 86, wherein the water is present in an
amount ranging from about 45% w/w to about 75 w/w of the adhesive
composition.
88. The composition of claim 86, further comprising urea.
89. The composition of claim 88, wherein the urea is present in an
amount ranging from about 0.5% w/w to about 5% w/w of the adhesive
composition.
90. The composition of claim 83, wherein the reactive prepolymer is
a polyisocyanate-based prepolymer, an epoxy-based prepolymer, a
latex-based prepolymer, a latex prepolymer, or a combination
thereof.
91. The composition of claim 83, wherein the reactive prepolymer is
a polyisocyanate-based prepolymer.
92. (canceled)
93. The composition of claim 83, wherein the reactive prepolymer is
polymeric diphenylmethane diisocyanate.
94. The composition of claim 83, wherein the plant protein
composition is ground plant meal.
95. A phenol-formaldehyde-plant protein adhesive composition
comprising: (a) phenol and formaldehyde that together constitute
from about 0.5% w/w to about 10% w/w of the adhesive composition;
(b) ground plant meal in an amount ranging from about 10% w/w to
about 30% w/w of the adhesive composition; (c) polymeric
diphenylmethane diisocyanate in an amount ranging from about 10%
w/w to about 30% w/w of the adhesive composition; and (d) water in
an amount ranging from about 45% w/w to about 75% w/w of the
adhesive composition.
96. The composition of claim 95, further comprising urea in an
amount ranging from about 0.5% w/w to about 5% w/w of the adhesive
composition.
97. (canceled)
98. The composition of claim 95, wherein the ratio of (i) weight
percent of polymeric diphenylmethane diisocyanate in the adhesive
composition to (ii) weight percent plant protein composition in the
adhesive composition is in the range of about 3:1 to about 1:2.
99. The composition of claim 98, wherein the ground plant meal has
a particle size in the range of from about 1 .mu.m to about 200
.mu.m.
100. (canceled)
101. The composition of claim 95, wherein the ground plant meal is
derived from corn, wheat, sunflower, cotton, rapeseed, canola,
castor, soy, camelina, flax, jatropha, mallow, peanuts, algae,
sugarcane begasse, tobacco, whey, or a combination thereof.
102. A solid binder composition formed by curing a composition of
claim 83.
103. A method of bonding a first article to a second article
comprising: (a) depositing on a surface of the first article the
adhesive composition of claim 83 thereby to create a binding area;
and (b) contacting the binding surface with a surface of the second
article thereby to bond the first article to the second
article.
104. The method of claim 103, further comprising the step of, after
step (b), permitting the adhesive composition to cure.
105. A method of producing a composite material comprising: (a)
combining a first article and a second article with the adhesive
composition of claim 83 to produce a mixture; and (b) curing the
mixture produced by step (a) to produce the composite material.
106. (canceled)
107. The method of claim 103, wherein the first article, the second
article or both the first and second articles are lignocellulosic
materials, or composite materials containing lignocellulosic
material.
108. (canceled)
109. An article produced using the adhesive composition of claim
83.
110. The article of claim 109, wherein the article is a
composite.
111. The article of claim 110, wherein the composite is a random
non-oriented homogeneous composite, an oriented composite, or a
laminated composite.
112. The article of claim 110, wherein the composite is chip board,
particle board, fiber board, oriented strand board, plywood,
laminated veneer lumber, glulam, laminated whole lumber, laminated
composite lumber, composite wooden I-beams, medium density
fiberboard, high density fiberboard, extruded wood, or
fiberglass.
113. The article of claim 109, wherein the article is a particle
board composite.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to U.S.
Provisional Patent Application Ser. No. 61/532,832, filed Sep. 9,
2011, and to U.S. Provisional Patent Application Ser. No.
61/567,769, filed Dec. 7, 2011, the contents of each of which are
hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates to protein adhesives, and to methods
of making and using such adhesives. The protein adhesives contain
ground plant meal or an isolated polypeptide composition obtained
from plant biomass, and are useful in the preparation of various
wood products.
BACKGROUND
[0003] Adhesive compositions are used extensively in the wood
products industry to make composites such as chipboard, fiberboard,
and related composite wood products. Adhesive compositions are also
used to make engineered lumber composites. Recent environmental
concerns emphasize the need for adhesive compositions that are
environmentally friendly. Adhesive compositions frequently used in
the wood products industry, however, are not environmentally
friendly. Thus, the need exists for adhesive compositions that
reduce the need for petroleum feedstock, minimize use of toxic
chemicals, and are amenable to the cure conditions and performance
requirements for wood products.
[0004] In response to the need for environmentally friendly
adhesive compositions, there has been renewed interest in using
certain soy products to form adhesive compositions. However, there
are multiple challenges in developing an adhesive composition from
soy products. For example, the adhesive composition when cured to
form a binder must have sufficient bond strength. The adhesive
composition when cured to form a binder should, for certain
applications, be sufficiently resistant to moisture. Another
challenge is that the adhesive composition must have sufficient pot
life so that it does not cure before being applied to components in
the wood product. It is also important that the soy product be
capable of production on large scale at economically feasible
terms, and that it is amenable to cure conditions used to form the
wood product.
[0005] Various reports describe efforts at developing an adhesive
composition using certain soy products. U.S. Patent Application
publication 2008/0021187 describes an adhesive composition
containing urea-denatured soy flour. U.S. Pat. No. 7,416,598
describes an adhesive composition containing a protein ingredient
and a modifying ingredient. Zhong and coworkers describe an
adhesive composition containing certain soy protein material that
has been modified. Zhong et al. in J. Appl. Polym. Sci. (2007) 103:
2261-2270. Yet, despite these efforts, the need exists for an
environmentally friendly adhesive composition that meets the
demands for widespread industrial application in the wood products
industry.
[0006] The present invention addresses this need, and provides
other related advantages.
SUMMARY OF THE INVENTION
[0007] The invention provides protein adhesive compositions,
methods of making and using such adhesives, and articles prepared
using such adhesives. The protein adhesive compositions contain a
plant protein composition, such as ground plant meal or an isolated
polypeptide composition obtained from plant biomass. The adhesive
compositions also contain, for example, a lignin, hydroxyaromatic
compound and an aldehyde source, a urea compound and an aldehyde
source, and/or an amine compound and an aldehyde source. The plant
protein composition is advantageous because it is prepared from
plant biomass, a renewable feedstock that is generally a waste
by-product of the agricultural industry. The adhesive compositions
are useful in preparing wood composites, such as particle
board.
[0008] Accordingly, one type of protein adhesive composition
provided by the invention contains lignin and a plant protein
composition. Lignin is a biopolymer that can be isolated from wood.
It has been unexpectedly discovered that use of lignin in
combination with plant protein compositions described herein
provide an adhesive that can be applied to wood particles to form a
particle board composite. Experiments using lignin alone failed to
produce a formulation with sufficient cohesive strength to produce
a particle board composite. Accordingly, one aspect of the
invention provides an adhesive composition comprising lignin and a
plant protein composition.
[0009] Another type of protein adhesive composition provided by the
invention contains a hydroxyaromatic compound (e.g., phenol), an
aldehyde source, and a plant protein composition selected from the
group consisting of ground plant meal and isolated polypeptide
composition. The plant protein composition is contemplated to
provide performance benefits to the adhesive composition. The
aldehyde source may be an aldehyde or a composition that releases
an aldehyde (e.g., formaldehyde) in situ. Accordingly, another
aspect of the invention provides a hydroxyaromatic-aldehyde
adhesive composition comprising a hydroxyaromatic compound, an
aldehyde source, and a plant protein composition selected from the
group consisting of ground plant meal and isolated polypeptide
composition. A more specific embodiment of such protein adhesives
relates to a phenol-formaldehyde-plant protein adhesive composition
that comprises: (a) phenol; (b) formaldehyde; (c) a plant protein
composition selected from the group consisting of ground plant meal
and isolated polypeptide composition; and (d) a reactive
prepolymer; wherein the ratio of (i) weight percent of reactive
prepolymer in the adhesive composition to (ii) the sum of the
weight percent of phenol and formaldehyde in the adhesive
composition is greater than 1:1. A second more specific embodiment
of such protein adhesives relates to a phenol-formaldehyde-plant
protein adhesive composition that comprises: (a) phenol and
formaldehyde that together constitute from about 0.5% w/w to about
10% w/w of the adhesive composition; (b) ground plant meal in an
amount ranging from about 10% w/w to about 30% w/w of the adhesive
composition; (c) polymeric diphenylmethane diisocyanate in an
amount ranging from about 10% w/w to about 30% w/w of the adhesive
composition; and (d) water in an amount ranging from about 45% w/w
to about 75% w/w of the adhesive composition.
[0010] Yet another type of protein adhesive composition provided by
the invention contains a urea compound, an aldehyde source, and a
plant protein composition selected from the group consisting of
ground plant meal and isolated polypeptide composition. The plant
protein composition is contemplated to provide performance benefits
to the adhesive composition. The aldehyde source may be an aldehyde
or a composition that releases an aldehyde (e.g., formaldehyde) in
situ. Accordingly, another aspect of the invention provides a urea
compound-aldehyde adhesive composition comprising a urea compound,
an aldehyde source, and a plant protein composition selected from
the group consisting of ground plant meal and isolated polypeptide
composition.
[0011] Yet another type of protein adhesive composition provided by
the invention contains an amine compound, an aldehyde source, and a
plant protein composition selected from the group consisting of
ground plant meal and isolated polypeptide composition. The plant
protein composition is contemplated to provide performance benefits
to the adhesive composition. The aldehyde source may be an aldehyde
or a composition that releases an aldehyde (e.g., formaldehyde) in
situ. Accordingly, another aspect of the invention provides an
amine compound-aldehyde adhesive composition comprising an amine
compound selected from the group consisting of a primary amine
compound and second amine compound, an aldehyde source, and a plant
protein composition selected from the group consisting of ground
plant meal and isolated polypeptide composition.
[0012] In another aspect, the invention provides a solid binder
composition formed by curing an adhesive composition described
herein.
[0013] In another aspect, the invention provides a method of
bonding a first article to a second article. The method comprises
the steps of (a) depositing on a surface of the first article any
one of the foregoing adhesive compositions thereby to create a
binding area; and (b) contacting the binding surface with a surface
of the second article thereby to bond the first article to the
second article. The method optionally also comprises the step of,
after step (b), permitting the adhesive composition to cure, which
can be facilitated by the application of pressure, heat or both
pressure and heat.
[0014] In another aspect, the invention provides a method of
producing a composite material. The method comprises the steps of
(a) combining a first article and a second article with any one of
the foregoing adhesive compositions to produce a mixture; and (b)
curing the mixture produced by step (a) to produce the composite
material. The curing can comprise applying pressure, heat or both
pressure and heat to the mixture.
[0015] In certain embodiments, the first article, the second
article or both the first and second articles are lignocellulosic
materials, or composite materials containing lignocellulosic
material. The first article, the second article or both the first
and second articles can comprise a metal, a resin, a ceramic, a
polymer, a glass or a combination thereof. The first article, the
second article, or both the first article and the second article
can be a composite. In addition, the invention provides an article
produced by each of the foregoing methods of manufacture.
[0016] In addition, the invention provides an article comprising
two or more components bonded together using one or more of the
adhesive compositions described herein. The bonded components can
be selected from the group consisting of paper, wood, glass, metal,
fiberglass, wood fiber, ceramic, ceramic powder, plastic (for
example, a thermoset plastic), and a combination thereof. In
certain other embodiments, the bonded components can be selected
from the group consisting of paper, wood, glass, metal, fiberglass,
wood fiber, ceramic, ceramic powder, sand, plastic (for example, a
thermoset plastic), and a combination thereof. The invention
provides an article (for example, a composite material, laminate,
or a laminate containing composite material) produced using one or
more of the adhesive compositions described herein.
[0017] The composite material can be chip board, particle board,
fiber board, plywood, laminated veneer lumber, glulam, laminated
whole lumber, laminated composite lumber, composite wooden I-beams,
medium density fiberboard, high density fiberboard, orientated
strand board, extruded wood, or fiberglass. The composite can be a
thermosetting composite or a thermoplastic composite.
[0018] In certain embodiments, the article is a composite, such as
a random non-oriented homogeneous composite, an oriented composite,
or a laminated composite. In certain other embodiments, the article
comprises a lignocellulosic component. Furthermore, the article can
comprise paper, wood, glass, fiberglass, wood fiber, ceramic,
ceramic powder, or a combination thereof.
[0019] In certain embodiments, the article is a particle board
composite. The amount of wood and adhesive composition used to
prepare the particle board composite can be adjusted to optimize
the performance properties of the particle board for different
applications (e.g., outdoor use where increased water resistance is
desirable). In certain embodiments, the composite comprises at
least about 80% (w/w) wood, at least about 90% (w/w) wood, at least
about 95% (w/w) wood, or at least about 98% (w/w) wood.
[0020] Depending upon the adhesive used, the resulting article can
have one or more of the following features: the article is moisture
resistant; the article remains intact after boiling in water for 5
minutes; two or more components of the article remain bonded after
boiling in water for 5 minutes; the article, when boiled in water
for 5 minutes, displays less than a 20% increase in volume relative
to the article prior to exposure to the water; and when the article
(for example, a composite material, laminate, or a laminate
containing a composite material) contains a lignocellulosic
material in the composite material or laminate, the article
exhibits no less than 50%, optionally no less than 75%, cohesive
failure of the lignocellulosic component when the article is placed
under a loading stress sufficient to break the article. In certain
embodiments, the article exhibits no less than 50% cohesive failure
of the lignocellulosic component when the article is placed under a
loading stress sufficient to break the article.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The foregoing and other objects, features and advantages of
the invention will become apparent from the following description
of preferred embodiments, as illustrated in the accompanying
drawings. Like-referenced elements identify common features in the
corresponding drawings. The drawings are not necessarily to scale,
with emphasis instead being placed on illustrating the principles
of the present invention, in which:
[0022] FIG. 1 is a flow chart showing the steps of an exemplary
method for producing isolated polypeptide compositions useful in
the practice of the invention;
[0023] FIG. 2 shows overlaid solid state FTIR spectra for
water-soluble and water-insoluble protein fractions isolated from
digested castor lot 5-90;
[0024] FIG. 3 shows solid state FTIR spectra of isolated
water-soluble and water-insoluble fractions from digested castor,
where the carbonyl amide region is expanded;
[0025] FIG. 4 shows solid state FTIR spectra of isolated
water-soluble and water-insoluble fractions from digested castor
where the N--H stretching region is expanded;
[0026] FIG. 5 shows overlaid solid state FTIR spectra of isolated
fractions from castor protein (lot 5-94), showing an expansion of
the carbonyl amide region (water-soluble fraction, and
water-insoluble/water-dispersible fraction);
[0027] FIG. 6 shows the solid state FTIR spectra of isolated
water-soluble and water-insoluble fractions from castor protein
(lot 5-94), where the N--H and O--H stretch regions are
expanded;
[0028] FIG. 7 shows overlaid solid state FTIR spectra of the
isolated water-insoluble/water-dispersible fractions from castor
protein (lot 5-94) and from enzyme digested castor (lot 5-90);
[0029] FIG. 8 shows overlaid solid state FTIR spectra of isolated
water-soluble and water-insoluble fractions from digested soy,
where the carbonyl amide region is expanded, where the spectra were
vertically scaled to achieve equivalent absorbance intensities for
the amide-I carbonyl stretch;
[0030] FIG. 9 shows overlaid solid state FTIR spectra of isolated
water-soluble and water-insoluble fractions from digested soy,
where the N--H stretching region is expanded;
[0031] FIG. 10 shows overlaid solid state FTIR spectra of isolated
water-soluble polypeptide fractions from digested soy and digested
castor;
[0032] FIG. 11 shows overlaid solid state FTIR spectra of isolated
water-insoluble fractions from digested soy and soy flour;
[0033] FIG. 12 shows overlaid solid state FTIR surface ATR spectra
of the isolated water-insoluble/water-dispersible fractions from
multiple protein samples (digested soy lot 5-81, soy flour, castor
protein isolate lot 5-94, digested castor lot 5-90) where the
carbonyl amide region is expanded;
[0034] FIG. 13 is a two-dimensional HSQC .sup.1H--.sup.15N NMR
spectrum for digested castor (lot 5-83) in d6-DMSO, showing two
regions of interest denoted Region A and Region B;
[0035] FIG. 14 is a two-dimensional HSQC .sup.1H--.sup.15N NMR
spectrum for water-insoluble/water-dispersible polypeptide fraction
derived from digested castor (lot 5-83) in d6-DMSO, again showing
Region A and Region B;
[0036] FIG. 15 is a two-dimensional HSQC .sup.1H--.sup.15N NMR
spectrum, where Region A from FIG. 14 has been magnified;
[0037] FIG. 16 shows solid state FTIR spectra of isolated
water-soluble and water-insoluble fractions obtained from ground
soy meal, where the N--H and O--H stretch regions are expanded;
[0038] FIG. 17 shows overlaid solid state FTIR spectra of isolated
water-soluble and water-insoluble fractions obtained from ground
soy meal, where the carbonyl amide region is expanded and the
spectra were vertically scaled to achieve equivalent absorbance
intensities for the amide-I carbonyl stretch;
[0039] FIG. 18 shows overlaid solid state FTIR spectra of isolated
water-soluble and water-insoluble/water-dispersible protein
fractions obtained from ground canola meal, where the N--H and O--H
stretch regions are expanded, as described further in Example
5;
[0040] FIG. 19 shows overlaid solid state FTIR spectra of isolated
water-soluble and water-insoluble/water-dispersible protein
fractions obtained from ground canola meal, where the carbonyl
amide region is expanded and the spectra were vertically scaled to
achieve equivalent absorbance intensities for the amide-I carbonyl
stretch, as described further in Example 5;
[0041] FIG. 20 shows overlaid solid state FTIR spectra of isolated
water-soluble and water-insoluble/water-dispersible protein
fractions obtained from soy flour, as described further in Example
5;
[0042] FIG. 21 shows overlaid solid state FTIR spectra of isolated
water-insoluble/water-dispersible protein fractions obtained from
soy meal and soy flour, as described further in Example 5; and
[0043] FIG. 22 shows particle board composites prepared in Example
6, along with samples TP-12 and TP-13 that cohesively disintegrated
upon removing them from the press.
DETAILED DESCRIPTION
[0044] The invention provides protein adhesive compositions and
methods of making and using such adhesives. Also, the invention
provides articles, such as wood composites, made using the protein
adhesive compositions. The protein adhesive compositions described
herein contain a plant protein composition. The plant protein
composition is obtained from a renewable feedstock and provides
multiple advantages in the preparation of adhesive compositions.
The protein component is preferably ground plant meal or an
isolated polypeptide composition derived from plant meal. The
adhesive compositions also contain, for example, a lignin,
hydroxyaromatic compound and an aldehyde source, a urea compound
and an aldehyde source, and/or an amine compound and an aldehyde
source.
[0045] One type of protein adhesive composition provided by the
invention contains lignin and a plant protein composition. Another
type of protein adhesive composition provided by the invention
contains a hydroxyaromatic compound, an aldehyde source, and a
plant protein composition selected from the group consisting of
ground plant meal and isolated polypeptide composition. Yet another
type of protein adhesive composition provided by the invention
contains a urea compound, an aldehyde source, and a plant protein
composition selected from the group consisting of ground plant meal
and isolated polypeptide composition. Yet another type of protein
adhesive composition provided by the invention contains an amine
compound, an aldehyde source, and a plant protein composition
selected from the group consisting of ground plant meal and
isolated polypeptide composition. Features of these protein
adhesive compositions are described in more detail in the sections
below.
[0046] The adhesives described herein can be used in the production
of a variety of wood-based products including composite materials,
laminates, and laminates that contain composite materials. For
example, the adhesives can be used in the production of
consolidated wood composites, for example, chipboard (also known as
OSB), fiberboard, and related composite wood products, as well as
in the production of engineered lumber composites, for example,
I-beams (I-joists), laminated veneer lumber (LVL), and other types
of structural lumber composites.
[0047] The following sections describe lignin-containing protein
adhesives, hydroxyaromatic-aldehyde adhesive composition (e.g.,
phenol/formaldehyde adhesive compositions), urea compound-aldehyde
adhesive composition (e.g., urea/formaldehyde adhesive
compositions), amine compound-aldehyde adhesive composition (e.g.,
melamine/formaldehyde adhesive compositions), additives that may be
included in the adhesive compositions, and methods of using such
adhesives, and articles formed from such adhesives.
I. Lignin-Containing Protein Adhesives
[0048] It has been unexpectedly discovered that use of lignin in
combination with plant protein compositions described herein
provide an adhesive. The adhesive can be applied to wood particles
to form, for example, a particle board composite. As explained in
Example 6, experiments using lignin alone failed to produce a
formulation with sufficient cohesive strength to produce a particle
board composite.
[0049] Accordingly, one aspect of the invention provides an
adhesive composition comprising lignin and a plant protein
composition. Further description of lignin and plant protein
compositions is described in the sections below. The adhesive
composition may be in the form of a liquid. Alternatively, the
adhesive composition may be in the form of a dry mixture. The
adhesive composition may further comprise one or more additives,
such as the additives described in Section VIII below, which
include, for example, an intercalated clay, an exfoliated clay, and
a partially exfoliated clay.
[0050] In certain embodiments, the adhesive composition may further
comprise a reactive prepolymer. In certain other embodiments, the
adhesive composition may further comprise a hydroxyaromatic
compound (e.g., phenol) and an aldehyde source, such as those
described in Section II below. In certain other embodiments, the
adhesive composition may further comprise a urea compound (e.g.,
H.sub.2NC(O)NH.sub.2) and an aldehyde source, such as those
described in Section III below. In certain other embodiments, the
adhesive composition may further comprise an amine compound (e.g.,
melamine) and an aldehyde source, such as those described in
Section IV below. In yet other embodiments, the adhesive
composition further comprises an aldehyde source, such as an
aldehyde source described in Section IV below.
[0051] In certain embodiments, the adhesive composition further
comprises water. For example, in certain embodiments, water is
present in an amount of from about 30% w/w to about 65% w/w of the
adhesive composition. In certain other embodiments, water is
present in an amount of from about 20% w/w to about 50% w/w, about
30% w/w to about 60% w/w, about 40% w/w to about 70% w/w, about 50%
w/w to about 80% w/w, or about 10% w/w to about 90% w/w of the
adhesive composition.
[0052] The amount of lignin in the adhesive composition may be
adjusted to achieve certain performance properties. For example, in
certain embodiments, the adhesive composition comprises from about
1% w/w to about 50% w/w lignin, from about 1% w/w to about 35% w/w
lignin, from about 1% w/w to about 15% w/w lignin, from about 5%
w/w to about 35% w/w lignin, from about 15% w/w to about 35% w/w
lignin, or from about 20% w/w to about 45% w/w lignin. In certain
other embodiments, the adhesive composition comprises from about 5%
w/w to about 35% w/w lignin.
[0053] The amount of plant protein composition in the adhesive
composition may be adjusted to achieve certain performance
properties. For example, in certain embodiments, the adhesive
composition comprises from about 5% w/w to about 50% w/w plant
protein composition, from about 5% w/w to about 35% w/w plant
protein composition, from about 5% w/w to about 30% w/w plant
protein composition, from about 15% w/w to about 35% w/w plant
protein composition, or from about 20% w/w to about 30% w/w plant
protein composition. In certain other embodiments, the adhesive
composition comprises from about 15% w/w to about 35% w/w plant
protein composition.
[0054] The amount of plant protein composition may be selected
relative to the amount of lignin in the adhesive composition. For
example, in certain embodiments, the ratio of weight percent plant
protein composition in the adhesive composition to weight percent
lignin in the adhesive composition is from (a) 99.9:0.1 to
0.1:99.9, (b) 9:1 to 1:9, (c) 5:1 to 1:5, or (d) 2:1 to 1:2.
[0055] A more specific embodiment relates an adhesive composition
that comprises: (a) lignin in an amount ranging from about 5% w/w
to about 30% w/w of the adhesive composition; (b) ground plant meal
in an amount ranging from about 10% w/w to about 30% w/w of the
adhesive composition; and (c) water in an amount ranging from about
45% w/w to about 75% w/w of the adhesive composition. In certain
embodiments, the lignin has a weight average molecular weight of
about 10,000 g/mol to about 70,000 g/mol.
II. Hydroxyaromatic Compound/Aldehyde-Containing Protein
Adhesives
[0056] Another aspect of the invention provides a
hydroxyaromatic-aldehyde protein adhesive composition. The adhesive
composition comprises a hydroxyaromatic compound, an aldehyde
source, and a plant protein composition selected from the group
consisting of ground plant meal and isolated polypeptide
composition. The adhesive composition may be in the form of a
liquid. Alternatively, the adhesive composition may be in the form
of a dry mixture.
[0057] The adhesive composition may further comprise one or more
additives, such as the additives described in Section VIII below,
which include, for example, an intercalated clay, an exfoliated
clay, and a partially exfoliated clay. Further, the adhesive
composition may comprise lignin, such as a lignin described below
in Section V. Still further, in certain embodiments, the adhesive
composition may further comprise a reactive prepolymer, such as a
reactive prepolymer described below in Section VII.
[0058] The particular hydroxyaromatic compound may be selected to
achieve certain performance properties. Exemplary classes of
hydroxyaromatic compounds include alkyl-substituted phenols,
aryl-substituted phenols, cycloalkyl-substituted phenols,
alkenyl-substituted phenols, alkoxy-substituted phenols,
aryloxy-substituted phenols and halogen-substituted phenols.
Exemplary specific hydroxyaromatic compounds include phenol,
o-cresol, m-cresol, p-cresol, 3,5-xylenol, 3,4-xylenol,
2,3,4-trimethylphenol, 3-ethylphenol, 3,5-diethylphenol,
p-butylphenol, 3,5-dibutylphenol, p-amyl phenol, p-cyclohexyl
phenol, p-octyl phenol, 3,5 dicyclohexylphenol, p-phenylphenol,
p-crotylphenol, 3,5-dimethoxyphenol, 3,4,5-trimethoxyphenol,
p-ethoxyphenol, p-butoxyphenol, 3-methyl-4-methoxyphenol,
p-phenoxyphenol, resorcinol, and naphthol. In certain embodiments,
the hydroxyaromatic compound is phenol.
[0059] Various aldehyde source compounds are reported in the
literature and are contemplated to be amenable for use in the
present invention. For example, in certain embodiments, the
aldehyde source is an aldehyde compound or para-formaldehyde.
Exemplary classes of aldehyde compounds include an alkyl
monoaldehyde, an alkyl dialdehyde, a hydroxyalkyl monoaldehyde, a
hydroxyalkyl dialdehyde, an acyl monoaldehyde, and an acyl
dialdehyde. Exemplary specific aldehyde compounds include
formaldehyde, acetaldehyde, glyoxal, methyl glyoxal, glycoaldehyde,
propanedial, propionaldehyde, butyraldehyde, pentanal, hexanal,
dodecanal, octadecanal, cinnamaldehyde, furfuraldehyde,
benzaldehyde, and glutaraldehyde. In certain embodiments, the
aldehyde source is formaldehyde (i.e., HC(O)H), such as in the form
of formaldehyde gas. In certain other embodiments, the aldehyde
source is para-formaldehyde ("paraform"). Alternatively, chemicals
found in wood can serve as a source of formaldehyde, and, as such,
wood can be an aldehyde source.
[0060] The ratio of aldehyde source to hydroxyaromatic compound in
the adhesive composition may be adjusted to achieve certain
performance properties. For example, in certain embodiments, the
mole ratio of aldehyde source to hydroxyaromatic compound is from
about 0.5:1 to about 4:1, about 1.5:1 to about 3.5:1, or about
1.5:1 to about 2.5:1. In certain other embodiments, the mole ratio
of aldehyde source to hydroxyaromatic compound is from about 1:2 to
about 2:1. In certain other embodiments, the hydroxyaromatic
compound is phenol, the aldehyde source is formaldehyde, and the
mole ratio of formaldehyde to phenol is from about 1:2 to about
2:1.
[0061] In certain embodiments, the hydroxyaromatic compound and
aldehyde source together constitute from about 0.5% w/w to about
10% w/w, about 1% w/w to about 8% w/w, about 1% w/w to about 5%
w/w, or about 2% w/w to about 5% w/w of the adhesive composition.
In certain embodiments, the plant protein composition is present in
an amount ranging from about 5% w/w to about 40% w/w, about 10% w/w
to about 30% w/w, or about 15% w/w to about 25% w/w of the adhesive
composition. In embodiments where the adhesive composition further
comprises a reactive prepolymer, the reactive prepolymer may be
present in an amount ranging from about 5% w/w to about 40% w/w,
about 10% w/w to about 30% w/w, or about 15% w/w to about 25% w/w
of the adhesive composition.
[0062] The hydroxyaromatic-aldehyde protein adhesive compositions
may optionally further comprise a catalyst to facilitate
polymerization. Exemplary catalysts include bases such as sodium
hydroxide, caustic soda, potassium hydroxide, caustic potash,
calcium hydroxide, tetraalkyl ammonium hydroxides, barium
hydroxide, and other basic alkaline salts such as alkali metal
carbonate. Other exemplary catalysts include (i) mineral acids,
such as hydrochloric acid, hydrobromic acid, perchloric acid,
sulfuric acid, and nitric acid; (ii) sulfonic acids, such as
methanesulfonic acid, ethanesulfonic acid, cyclohexanesulfonic
acid, benzenesulfonic acid, p-toluenesulfonic acid,
trifluoromethane sulfonic acid, and camphorsulfonic acid; and (iii)
organic acids, such as formic acid, acetic acid, propionic acid,
cyclohexanecarboxylic acid, oxalic acid, malonic acid, maleic acid,
fumaric acid, citric acid, tartaric acid, and 3-mercaptopropionic
acid.
[0063] In certain embodiments, the adhesive composition further
comprises water. For example, in certain embodiments, water is
present in an amount of from about 30% w/w to about 65% w/w of the
adhesive composition. In certain other embodiments, water is
present in an amount of from about 20% w/w to about 50% w/w, about
30% w/w to about 60% w/w, about 40% w/w to about 70% w/w, about 50%
w/w to about 80% w/w, or about 10% w/w to about 90% w/w of the
adhesive composition.
[0064] A more specific embodiment relates to a
phenol-formaldehyde-plant protein adhesive composition that
comprises: (a) phenol; (b) formaldehyde; (c) a plant protein
composition selected from the group consisting of ground plant meal
and isolated polypeptide composition; and (d) a reactive
prepolymer; wherein the ratio of (i) weight percent of reactive
prepolymer in the adhesive composition to (ii) the sum of the
weight percent of phenol and formaldehyde in the adhesive
composition is greater than 1:1. In certain embodiments, the ratio
of (i) weight percent of reactive prepolymer in the adhesive
composition to (ii) the sum of the weight percent of phenol and
formaldehyde in the adhesive composition is in the range of about
3:1 to about 20:1. In certain embodiments, the ratio of (i) weight
percent of reactive prepolymer in the adhesive composition to (ii)
weight percent plant protein composition in the adhesive
composition is in the range of about 4:1 to about 1:4. In certain
embodiments, the composition further comprises water, such as where
the water is present in an amount ranging from about 45% w/w to
about 75% w/w of the adhesive composition. In certain embodiments,
the composition further comprises urea (i.e.,
H.sub.2NC(O)NH.sub.2), such as where the urea is present in an
amount ranging from about 0.5% w/w to about 5% w/w of the adhesive
composition.
[0065] Exemplary reactive prepolymers are described in Section VII
below. In certain embodiments, the reactive prepolymer is a
polyisocyanate-based prepolymer, an epoxy-based prepolymer, a
latex-based prepolymer, a latex prepolymer, or a combination
thereof. In certain other embodiments, the reactive prepolymer is a
polyisocyanate-based prepolymer. In certain other embodiments, the
polyisocyanate-based prepolymer is an organic polyisocyanate; or a
reaction product between an organic polyisocyanate and a
polypeptide, a polyol, an amine based polyol, an amine containing
compound, a hydroxy containing compound, or a combination thereof.
In certain other embodiments, the reactive prepolymer is polymeric
diphenylmethane diisocyanate.
[0066] In certain embodiments, the plant protein composition is
ground plant meal.
[0067] Another more specific embodiment relates
phenol-formaldehyde-plant protein adhesive composition that
comprises: (a) phenol and formaldehyde that together constitute
from about 0.5% w/w to about 10% w/w of the adhesive composition;
(b) ground plant meal in an amount ranging from about 10% w/w to
about 30% w/w of the adhesive composition; (c) polymeric
diphenylmethane diisocyanate in an amount ranging from about 10%
w/w to about 30% w/w of the adhesive composition; and (d) water in
an amount ranging from about 45% w/w to about 75% w/w of the
adhesive composition. In certain embodiments, the composition
further comprises urea (i.e., H.sub.2NC(O)NH.sub.2) in an amount
ranging from about 0.5% w/w to about 5% w/w of the adhesive
composition. In certain embodiments, the ratio of (i) weight
percent of polymeric diphenylmethane diisocyanate in the adhesive
composition to (ii) the sum of the weight percent of phenol and
formaldehyde in the adhesive composition is in the range of about
2:1 to about 5:1. In certain embodiments, the ratio of (i) weight
percent of polymeric diphenylmethane diisocyanate in the adhesive
composition to (ii) weight percent plant protein composition in the
adhesive composition is in the range of about 3:1 to about 1:2.
[0068] Another more specific embodiment relates
phenol-formaldehyde-plant protein adhesive composition that
comprises: (a) phenol and para-formaldehyde that together
constitute from about 0.5% w/w to about 10% w/w of the adhesive
composition; (b) ground plant meal in an amount ranging from about
10% w/w to about 30% w/w of the adhesive composition; (c) polymeric
diphenylmethane diisocyanate in an amount ranging from about 10%
w/w to about 30% w/w of the adhesive composition; and (d) water in
an amount ranging from about 45% w/w to about 75% w/w of the
adhesive composition. In certain embodiments, the composition
further comprises urea (i.e., H.sub.2NC(O)NH.sub.2) in an amount
ranging from about 0.5% w/w to about 5% w/w of the adhesive
composition. In certain embodiments, the ratio of (i) weight
percent of polymeric diphenylmethane diisocyanate in the adhesive
composition to (ii) the sum of the weight percent of phenol and
para-formaldehyde in the adhesive composition is in the range of
about 2:1 to about 5:1. In certain embodiments, the ratio of (i)
weight percent of polymeric diphenylmethane diisocyanate in the
adhesive composition to (ii) weight percent plant protein
composition in the adhesive composition is in the range of about
3:1 to about 1:2.
III. Urea Compound/Aldehyde-Containing Protein Adhesives
[0069] Another aspect of the invention provides a urea
compound-aldehyde protein adhesive composition. The adhesive
composition comprises a urea compound, an aldehyde source, and a
plant protein composition selected from the group consisting of
ground plant meal and isolated polypeptide composition.
[0070] The adhesive composition may further comprise one or more
additives, such as the additives described in Section VIII below,
which include, for example, an intercalated clay, an exfoliated
clay, and a partially exfoliated clay. Further, the adhesive
composition may comprise lignin, such as a lignin described below
in Section V. Still further, in certain embodiments, the adhesive
composition may further comprise a reactive prepolymer, such as a
reactive prepolymer described below in Section VII.
[0071] The particular urea compound may be selected to achieve
certain performance properties. Exemplary classes of urea compounds
include alkyl ureas, aralkyl ureas, aryl ureas, mono-methylolurea,
a di-methylolurea, a tri-methylolurea, and substituted noncyclic
ureas. Exemplary specific urea compounds include
H.sub.2NC(O)NH.sub.2, ethylene urea, propylene urea,
tetrahydro-5-(2-hydroxyethyl)-1,3,5-triazin-2-one,
4,5-dihydroxy-2-imidazolidone, 4,5-dimethoxy-2-imidazolidinone,
4-methyl ethylene urea, 4-ethyl ethylene urea, 4-hydroxyethyl
ethylene urea, 4,5-dimethyl ethylene urea, 4-hydroxy-5-methyl
propylene urea, 4-methoxy-5-methyl propylene urea,
4-hydroxy-5,5-dimethyl propylene urea, 4-methoxy-5,5-dimethyl
propylene urea, tetrahydro-5-(ethyl)-1,3,5-triazin-2-one,
tetrahydro-5-(propyl)-1,3,5-triazin-2-one,
tetrahydro-5-(butyl)-1,3,5-triazin-2-one, dihydro-5-methyl-2(1H,
3H)pyrimidinone, dihydro-5,5-dimethyl-2 (1H)pyrimidinone,
tetrahydro-4,5-methyl-2(1H) pyrimidinone, and
tetrahydro-4-(2-hydroxyethyl)-5,5-dimethyl-2(1H) pyrimidinone.
Additional urea compounds include those represented by
RN(H)C(O)NH.sub.2, R.sub.2NC(O)NH.sub.2, or RN(H)C(O)N(H)R, wherein
R represents independently for each occurrence H, alkyl, aryl, or
aralkyl. In certain embodiments, the urea compound has the formula
RN(H)C(O)N(H)R, wherein R represents independently for each
occurrence H, alkyl, aryl, or aralkyl. In certain other
embodiments, the urea compound is H.sub.2NC(O)NH.sub.2,
H.sub.2NC(O)N(H)Me, MeN(H)C(O)N(H)Me, or
H.sub.2NC(O)N(CH.sub.3).sub.2. In certain other embodiments the
urea compound is [CH.sub.3CH.sub.2N(H)].sub.2C(O),
[(CH.sub.3).sub.2N].sub.2C(O), or CH.sub.3CH.sub.2N(H)C(O)NH.sub.2.
In still other embodiments, the urea compound is
H.sub.2NC(O)NH.sub.2.
[0072] Various aldehyde source compounds are reported in the
literature and are contemplated to be amenable for use in the
present invention. For example, in certain embodiments, the
aldehyde source is an aldehyde compound or para-formaldehyde.
Exemplary classes of aldehyde compounds include an alkyl
monoaldehyde, an alkyl dialdehyde, a hydroxyalkyl monoaldehyde, a
hydroxyalkyl dialdehyde, an acyl monoaldehyde, and an acyl
dialdehyde. Exemplary specific aldehyde compounds include
formaldehyde, acetaldehyde, glyoxal, methyl glyoxal, glycoaldehyde,
propanedial, propionaldehyde, butyraldehyde, pentanal, hexanal,
dodecanal, octadecanal, cinnamaldehyde, furfuraldehyde,
benzaldehyde, and glutaraldehyde. In certain embodiments, the
aldehyde source is formaldehyde (i.e., HC(O)H), such as in the form
of formaldehyde gas. In certain other embodiments, the aldehyde
source is para-formaldehyde ("paraform"). Alternatively, chemicals
found in wood can serve as a source of formaldehyde, and, as such,
wood can be an aldehyde source.
[0073] The ratio of aldehyde source to urea compound in the
adhesive composition may be adjusted to achieve certain performance
properties. For example, in certain embodiments, the mole ratio of
aldehyde source to urea compound is from about 0.5:1 to about 4:1,
about 1.5:1 to about 3.5:1, or about 1.5:1 to about 2.5:1.
[0074] The urea compound-aldehyde protein adhesive compositions may
optionally further comprise a catalyst to facilitate
polymerization. Exemplary catalysts include Lewis acids, Bronsted
acids, ammonium salts, substituted ammonium salts, or a combination
thereof. In certain embodiments, the catalyst is AlCl.sub.3,
AlBr.sub.3, Al.sub.2(SO.sub.4).sub.3, MgCl.sub.2, MgBr.sub.2, Ca,
Sr, Ti, Fe, Zn, Sn, Sb, Zr, Hg, TI, Pb, Bl, HCl, H.sub.2SO.sub.4,
HNO.sub.3, H.sub.3PO.sub.4, or HClO.sub.4.
IV. Amine Compound-Aldehyde-Containing Protein Adhesives
[0075] Another aspect of the invention provides an amine
compound-aldehyde adhesive composition. The adhesive composition
comprises an amine compound selected from the group consisting of a
primary amine compound and a secondary amine compound, an aldehyde
source, and a plant protein composition selected from the group
consisting of ground plant meal and isolated polypeptide
composition.
[0076] The adhesive composition may further comprise one or more
additives, such as the additives described in Section VIII below,
which include, for example, an intercalated clay, an exfoliated
clay, and a partially exfoliated clay. Further, the adhesive
composition may comprise lignin, such as a lignin described below
in Section V. Still further, in certain embodiments, the adhesive
composition may further comprise a reactive prepolymer, such as a
reactive prepolymer described below in Section VII.
[0077] The particular amine compound may be selected to achieve
certain performance properties. In certain embodiments, the amine
compound is a primary amine compound, such as a primary alkyl
amine, primary arylamine, primary heteroarylamine, or primary
aralkyl amine. In certain embodiments, the amine compound is
melamine.
[0078] Various aldehyde source compounds are reported in the
literature and are contemplated to be amenable for use in the
present invention. For example, in certain embodiments, the
aldehyde source is an aldehyde compound or para-formaldehyde.
Exemplary classes of aldehyde compounds include an alkyl
monoaldehyde, an alkyl dialdehyde, a hydroxyalkyl monoaldehyde, a
hydroxyalkyl dialdehyde, an acyl monoaldehyde, and an acyl
dialdehyde. Exemplary specific aldehyde compounds include
formaldehyde, acetaldehyde, glyoxal, methyl glyoxal, glycoaldehyde,
propanedial, propionaldehyde, butyraldehyde, pentanal, hexanal,
dodecanal, octadecanal, cinnamaldehyde, furfuraldehyde,
benzaldehyde, and glutaraldehyde. In certain embodiments, the
aldehyde source is formaldehyde (i.e., HC(O)H), such as in the form
of formaldehyde gas. In certain other embodiments, the aldehyde
source is para-formaldehyde ("paraform"). Alternatively, chemicals
found in wood can serve as a source of formaldehyde, and, as such,
wood can be an aldehyde source.
[0079] The ratio of aldehyde source to amine compound in the
adhesive composition may be adjusted to achieve certain performance
properties. For example, in certain embodiments, the mole ratio of
aldehyde source to amine compound is from about 0.5:1 to about 4:1,
about 1.5:1 to about 3.5:1, or about 1.5:1 to about 2.5:1.
V. Lignin
[0080] Lignin is a polyphenolic polymer that can be isolated from
wood. Lignin can be characterized according to the natural source
from which it is obtained. In addition, lignin can be characterized
according to physical properties such as solubility, molecular
weight, temperature stability, salt tolerance, surface tension,
sulphonic sulphur content, presence of cations, quantity of
calcitrant, its phenoxy radical signal, and amount of
p-hydroxyphenyl, guaiacyl, and/or synringal moieties in its
structure.
[0081] One type of lignin contemplated to be amenable for use in
the adhesive compositions described herein is lignin obtained from
hardwood trees, such as Acacia, Afzelia, Synsepalum duloificum,
Albizia, Alder, Applewood, Arbutus, Ash, Aspen, Australian Red
Cedar, Ayna, Balsa, Basswood, Beech, Birch, Blackbean, Blackwood,
Bocote, Boxelder, Boxwood, Brazilwood, Bubing a, Buckeye,
Butternut, Catalpa, Chemy, Crabwood, Chestnut, Coachwood, Cocobolo,
Corkwood, Cottonwood, Cucumbertree, Dogwood, Ebony, Elm,
Eucalyptus, Greenheart, Grenadilla, Gum, Hickory, Hornbeam,
Hophombeam, Ipe, Iroko, Ironwood, Jacaranda, Jotoba, Lacewood,
Laurel, Limba, Lignum vitae, Locust, Mahogany, Maple, Meranti,
Mpingo, Oak, Obeche, Okoume, Oregon Myrtle, California Bay Laurel,
Pear, Poplar, Ramin, Red cedar, Rosewood, Sal, Sandalwood,
Sassafras, Satinwood, Silky Oak, Silver Watde, Snakewood, Sourwood,
Spanish cedar, American sycamore, Teak, Walnut, Willow, Yellow
poplar, Bamboo, and Palmwood.
[0082] Another type of lignin contemplated to be amenable for use
in the adhesive compositions described herein is lignin obtained
from softwood trees, such as Araucaria, softwood Cedar, Cypress,
Rocky Mountain Douglas fir, European Yew, Fir, Hemlock, Kauri,
Kaya, Larch, Pine, Redwood, Rimu, Spruce, and Sugi.
[0083] Another type of lignin contemplated to be amenable for use
in the adhesive compositions described herein is lignin obtained
from annual fibre, such as flax, wheat, barley, oats, sugarcane
bagasse, rice straw, corn stover, hemp, fruit pulp, alfa grass,
switchgrass, corn cobs, and fruit peals.
[0084] Another type of lignin contemplated to be amenable for use
in the adhesive compositions described herein is lignin having one
or more of the following physical properties: (i) a weight average
molecular weight of about 1,000 g/mol to about 100,000 g/mol, about
10,000 g/mol to about 70,000 g/mol, or about 5,000 to about 50,000;
(ii) a temperature stability of about 50.degree. C. to about
400.degree. C., about 70.degree. C. to about 250.degree. C., or
about 90.degree. C. to about 200.degree. C.; (iii) a salt tolerance
of less than 0.1% precipitate in a salt solution containing sodium
chloride, magnesium chloride, and/or calcium chloride with
concentrations of about 70 ppm to about 270 ppm total dissolved
solids; (iv) when mixed with water to produce a 1% aqueous
solution, the aqueous solution has a surface tension of 35 to 75
dynes/cm; and (v) has a phenoxy radical signal of about 500 gauss
to about 5,000 gauss, about 1000 gauss to about 3000 gauss, or
about 2000 gauss to about 4000 gauss. In certain embodiments, the
lignin has one or more of the following physical properties: (i) at
least 20% by weight p-hydroxyphenyl, (ii) at least 40% by weight
p-hydroxyphenyl, (iii) at least 20% by weight guaiacyl, (iv) at
least 40% by weight guaiacyl, (v) at least 20% by weight synringal,
and (vi) at least 40% by weight synringal.
[0085] Lignin can be isolated from wood and annual fibre using
procedures reported in the literature. Exemplary isolation
procedures include sulfite pulping, the Kraft process, organosolv
pulping (e.g., ASAM organosolv pulping), acid hydrolysis, soda
pulping, steam explosion, Alcell.RTM. pulping, Organocell pulping,
and Acetosolv pulping. In particular, the sulphate, sulphite,
ORGANOSOLV and MILOX processes can be used to isolate lignin.
Isolation procedures described in the literature can also be used
to obtain lignin sulfonates (also known as lignosulphonates and
sulfite lignins), kraft lignins (also called sulfate lignins),
alkali lignins, and oxylignins.
VI. Plant Protein Composition
[0086] The plant protein composition is derived from plant biomass
and, as such, provides the benefit that it is a renewable
feedstock. The plant protein composition may be ground plant meal
or an isolated polypeptide composition as described in more detail
below.
[0087] A. Ground Plant Meal
[0088] Plant meal can be obtained from commercial sources or
derived from corn, wheat, sunflower, cotton, rapeseed, canola,
castor, soy, camelina, flax, jatropha, mallow, peanuts, algae,
sugarcane bagasse, tobacco, whey, or a combination thereof. Plant
meal can be ground using techniques known in the art, such as
hammer mill (cryogenic or ambient) or ball mill. In certain
embodiments, the plant meal is ground and screened to isolate plant
meal particles having a particle size in the range of from about 1
.mu.m to about 400 .mu.m, from about 1 .mu.m to about 350 .mu.m,
from about 1 .mu.m to about 300 .mu.m, from about 1 .mu.m to about
250 .mu.m, from about 1 .mu.m to about 200 .mu.m, from about 1
.mu.m to about 100 .mu.m, from about 1 .mu.m to about 50 .mu.m,
from about 5 .mu.m to about 250 .mu.m, from about 5 .mu.m to about
200 .mu.m, from about 5 .mu.m to about 150 .mu.m, from about 5
.mu.m to about 100 .mu.m, from about 5 .mu.m to about 50 .mu.m,
from about 10 .mu.m to about 250 .mu.m, from about 10 .mu.m to
about 100 .mu.m, from about 10 .mu.m to about 90 .mu.m, from about
10 .mu.m to about 70 .mu.m, from about 10 .mu.m to about 50 .mu.m,
from about 20 .mu.m to about 150 .mu.m, from about 20 .mu.m to
about 100 .mu.m, from about 20 .mu.m to about 80 .mu.m, from about
20 .mu.m to about 70 .mu.m, from about 20 .mu.m to about 60 .mu.m,
from about 25 .mu.m to about 150 .mu.m, from about 25 .mu.m to
about 100 .mu.m, from about 25 .mu.m to about 50 .mu.m, from about
50 .mu.m to about 150 .mu.m, or from about 50 .mu.m to about 100
.mu.m. In certain embodiments, the plant meal is ground and has a
particle size in the range of from about 1 .mu.m to about 200
.mu.m. In certain other embodiments, the plant meal is ground and
has a particle size in the range of from about 1 .mu.m to about 100
.mu.m,
[0089] Preferred types of ground plant meal are characterized by
their ability to suspend or emulsify oil in water or water in oil
to produce a homogeneous suspension or emulsion stable, by visual
inspection, for least 5 minutes. In certain embodiments, the
dispersion or emulsion exhibits substantially no phase separation
by visual inspection for at least 10, 15, 20, 25, or 30 minutes, or
even 1, 2, 3, 4, 5, 6, 9, 12, 18, or 24 hours after mixing the
ground plant meal with the oil. One assay that can be used to
identify such preferred ground plant meals involves mixing 26 parts
(by weight) of a ground plant meal sample with 74 parts (by weight)
of water. The resulting solution or dispersion is mixed with 26
parts (by weight) of oil, for example, PMDI. Under these
conditions, the ground plant meal produces a dispersion or emulsion
that exhibits substantially no phase separation by visual
inspection for at least 5 minutes after mixing the ground plant
meal with the oil. This assay can be performed with oils other than
PMDI, such as mineral oil, soybean oil, derivatized soybean oil,
motor oil, castor oil, derivatized castor oil, dibutyl phthalate,
epoxidized soybean oil, corn oil, vegetable oil, caprylic
triglyceride, Eucalyptus oil, tributyl o-acetylcitrate, or an
organic polyisocyanate other than PMDI.
[0090] An additive may be added to the plant meal prior to grinding
to aid in the grinding process or produce a ground plant meal with
superior physical properties for use in manufacturing an adhesive
composition, e.g., providing a ground plant meal with improved flow
properties, superior packing density, reduced tendency to cake,
reduced tendency to bridge, superior particle dispersibility in
aqueous mixtures, modulation of particle coupling and/or wetting
characteristics with other materials in the adhesive composition,
and the like. Alternatively, the additive may be added to the plant
meal during the grinding process used to produce ground plant
meal.
[0091] Additives that impart superior performance properties to the
adhesive composition or the wood composite formed from the adhesive
composition may be added to the plant meal before or during
grinding or may be added to the ground plant meal produced from the
grinding process. Exemplary additives include those described in
sections below, and, in particular, include agents that improve
moisture resistance of the wood composite, formaldehyde scavenging
agents, and composite-release promoting agents. The additive may be
in solid or liquid form, and the additive may be characterized
according to whether it reacts with materials in the adhesive
composition or does not react with materials in the adhesive
composition.
[0092] Exemplary solid additives include (i) inorganic additives
such as silica, pigments, catalysts, clays (including intercalated
clays, exfoliated clays, and partially exfoliated clays), and the
like, and (ii) organic compounds such as fatty acids (e.g., stearic
acid, lauric acid) lignin, tannins, amine-containing compounds,
urea, hydrocarbon waxes/liquids, and fluorocarbon waxes/liquids.
Solid additives may be used in amounts ranging, for example, from
about 0.001% w/w to 40% w/w of the ground plant meal mixture, from
about 0.1% w/w to about 20% w/w of the ground plant meal mixture,
or from about 0.5% w/w to about 15% w/w of the ground plant meal
mixture.
[0093] Liquid additives may be dry blended with ground plant meal.
The amount of liquid additive should be less than that which causes
the ground plant meal to cake or bridge during a manufacturing
process. Accordingly, in certain embodiments, the amount of liquid
additive(s) is less than about 10% by weight of the ground plant
meal mixture containing the additive(s). In certain other
embodiments, the amount of liquid additive(s) is less than about 5%
by weight, or even less than about 2% by weight, of the ground
plant meal mixture containing the additive. The liquid additive may
be characterized as reactive or non-reactive. Reactive liquid
additives may include organosilanes, low molecular weight alcohols
such as glycerin or propylene glycol, liquid polyol oligomers,
liquid polyurethane oligomers, addition-polymerizable monomers,
condensation-polymerizable monomers, and reactive oils such as
epoxidized soy oil or castor oil. Other liquid additives include
amalgams of a carrier oil and a partially exfoliated clay as
described herein.
[0094] B. Isolated Polypeptide Composition
[0095] The isolated polypeptide composition can be derived from
renewable plant biomass, such as corn, wheat, sunflower, cotton,
rapeseed, canola, castor, soy, camelina, flax, jatropha, mallow,
peanuts, algae, sugarcane bagasse, tobacco, whey, or a combination
thereof, using procedures described herein. The isolated
polypeptide composition contains water-insoluble/water-dispersible
protein fraction, optionally in combination with a water-soluble
protein fraction. It is understood that the
water-insoluble/water-dispersible protein fraction can disperse
oils (for example, reactive oils, or an organic polyisocyanate,
which is a reactive prepolymer). Thus, in embodiments where the
isolated polypeptide composition contains a mixture of i)
water-insoluble/water-dispersible protein fraction and ii)
water-soluble protein fraction, the ratio of i)
water-insoluble/water-dispersible protein fraction to ii)
water-soluble protein fraction is such that the isolated
polypeptide composition is able to disperse a prepolymer in an
aqueous medium.
[0096] The terms "protein" and "polypeptide" are used synonymously
and refer to polymers containing amino acids that are joined
together, for example, via peptide bonds or other bonds, and may
contain naturally occurring amino acids or modified amino acids.
The polypeptides can be isolated from natural sources or
synthesized using standard chemistries. The polypeptides may be
modified or derivatized by either natural processes, such as
post-translational processing, or by chemical modification
techniques well known in the art. Modifications or derivatizations
may occur anywhere in the polypeptide, including, for example, the
peptide backbone, the amino acid side-chains and the amino or
carboxyl termini. Modifications include, for example, cyclization,
disulfide bond formation, demethylation, deamination, formation of
covalent cross-links, formation of pyroglutamate, formylation,
gamma-carboxylation, glycosylation, GPI anchor formation,
hydroxylation, iodination, methylation, myristolyation, oxidation,
pegylation, proteolytic digestion, phosphorylation, etc. As used
throughout, the term "isolated" refers to material that is removed
from its original environment (e.g., the natural environment if it
is naturally occurring).
[0097] 1. Preparation of Isolated Polypeptide Composition
[0098] The starting material for producing an isolated polypeptide
composition can be derived from one or more of corn, wheat,
sunflower, cotton, rapeseed, canola, castor, soy, camelina, flax,
jatropha, mallow, peanuts, algae, sugarcane bagasse, tobacco, or
whey. For example, the starting material for producing an isolated
polypeptide composition can be plant meal or a protein isolate.
Depending on the properties desired for the adhesive, the isolated
polypeptide composition may contain a mixture of i)
water-insoluble/water-dispersible protein fraction and ii)
water-soluble protein fraction. The
water-insoluble/water-dispersible protein fraction and the
water-soluble protein fraction can be obtained from plant material
using a Water Washing Method or an Acid Precipitation Method, such
as those described in more detail below. In certain instances, the
composition obtained from the Water Washing Method and or Acid
Precipitation Method may be further modified by enzymatic digestion
and/or chemical modification.
Water Washing Method
[0099] Water-insoluble/water-dispersible protein fraction can be
isolated from plant meal (e.g., castor meal, soy meal, or canola
meal) by washing with water to remove water-soluble proteins and
water-soluble components. The residue left after the water wash is
the water-insoluble/water-dispersible protein fraction. A
water-soluble protein fraction can be isolated by concentrating
aqueous extracts from the water washing. Plant meal used in the
process can be ground to reduce particle size, which may, in
certain instances, provide processing advantages.
[0100] Water-insoluble/water-dispersible protein fraction can also
be isolated from, for example, soy protein isolate or from soy
flour. The procedure involves washing the soy protein isolate or
soy flour with water to remove water-soluble proteins and
water-soluble components from the respective soy protein isolate or
the water-flour mixture.
[0101] The water-insoluble/water-dispersible protein fraction
described above may be used directly as a wet slurry in an adhesive
composition, or it may be dried and optionally ground to form a
particulate mixture.
[0102] In certain embodiments, the pH of the water used to wash the
plant meal is about 7. In certain other embodiments, the pH of the
water used to perform one or more of the washes may be alkaline.
Conditions (e.g., number of water washes) for the Water Washing
Method may be adjusted in order to maximize the performance
properties of the water-insoluble/water-dispersible protein
fraction, such as its ability to disperse an oil in water or water
in oil.
[0103] The Water Washing Method is a simple and economical
procedure for obtaining water-insoluble/water-dispersible protein
fraction. Due to the simplicity of the method, it is contemplated
that the Water Washing Method can be used to provide large
quantities of water-insoluble/water-dispersible protein fraction
for manufacture of adhesive compositions.
[0104] It is appreciated that the water-insoluble/water-dispersible
protein fraction obtained using the Water Washing Method may, in
certain instances, contain water-insoluble components in addition
to water-insoluble protein. If the performance requirements of an
adhesive require a water-insoluble/water-dispersible protein
fraction having a larger amount of water-insoluble protein, then
the Acid Precipitation Method can be used to prepare the
water-insoluble/water-dispersible protein fraction.
Acid Precipitation Method
[0105] Water-insoluble/water-dispersible protein fraction
comprising a relatively higher quantity of water-insoluble protein
can be prepared using the Acid Precipitation Method. The Acid
Precipitation Method is shown schematically in FIG. 1. This method
can also be used to obtain water-soluble protein fraction.
[0106] As shown in FIG. 1, the starting material (for example,
ground meal) is dispersed in alkaline, aqueous media at pH 6.5-13
for at least 5 minutes, at least 20 minutes, at least 40 minutes or
at least 1 hour, to form a mixture. Starting materials include, for
example, canola meal, canola protein isolate, castor meal, castor
protein isolate, soy meal, or soy protein isolate, or a combination
thereof. Then, the pH of the mixture is lowered by the addition of
acid (to provide a mixture with a pH in the range of, for example,
4.0-5.0) to precipitate both a portion of water-soluble proteins
and water-insoluble proteins. Then, the water-insoluble material
(i.e., the precipitate) is harvested. The harvested material is
washed with water and the remaining
water-insoluble/water-dispersible material is harvested. The
resulting water-insoluble/water-dispersible material can be used as
is or dried using drying techniques known in the art.
[0107] Further, as shown in FIG. 1, the water-soluble proteins can
be harvested at a number of places. For example, water-soluble
proteins can be harvested after the starting material is mixed in
aqueous media, after neutralization, and as a supernatant from the
washing steps. The resulting protein can be used as is or dried
using drying techniques known in the art.
[0108] The water-insoluble/water-dispersible material produced
according to the method in FIG. 1 can disperse or emulsify oil in
water or water in oil. The physical and chemical properties of the
water-soluble/water-dispersible fraction are described in more
detail below. In addition, the physical and chemical properties of
the water-soluble protein fraction are described in more detail
below.
Enzymatic Digestion/Chemical Hydrolysis
[0109] The Water Washing Method and Acid Precipitation Method can
include one or more enzyme digestion and/or chemical hydrolysis
steps. Digestion can be facilitated using one or more enzymes, and
hydrolysis can be facilitated using one or more chemicals, for
example, acid- or alkali-based hydrolysis. For example, in the Acid
Precipitation Method, the starting material (for example, the
ground meal) can be exposed to enzymatic digestion before or after,
or both before and after the incubation of the starting material in
the alkaline aqueous media. Alternatively, or in addition, an
enzymatic digestion step can be performed on the material following
addition of acid to provide a mixture with a pH in the range of 4.0
to 5.0. Alternatively, or in addition, the harvested
water-insoluble/water-dispersible material can be exposed to
enzymatic digestion prior to washing. Alternatively, or in
addition, the material harvested after washing can be exposed to
enzymatic digestion. Chemical hydrolysis, however, can occur with
or replace the enzymatic digestion steps noted above.
[0110] Under certain circumstances residual basic species and
alkali metals present in chemically digested proteins are not
compatible with polyisocyanates and can cause trimerization of the
isocyanate groups, leading to stability problems in the final
polyisocyanate compositions. Enzymatic digestion, however, can be
used to avoid or reduce isocyanate stability problems associated
with some chemical hydrolysis steps.
[0111] It is understood that enzymes useful in the digestion of the
protein fractions include endo- or exo-protease of bacterial,
fungal, animal or vegetable origin or a mixture of thereof. Useful
enzymes include, for example, a serine-, leucine-, lysine-, or
arginine-specific protease. Exemplary enzymes include trypsin,
chymotrypsins A, B and C, pepsin, rennin, microbial alkaline
proteases, papain, ficin, bromelain, cathepsin B, collagenase,
microbial neutral proteases, carboxypeptidases A, B and C,
camosinase, anserinase, V8 protease from Staphylococcus aureus and
many more known in the art. Also combinations of these proteases
may be used.
[0112] Also commercially available enzyme preparations such as, for
example, Alcalase.RTM., Chymotrypsine 800s, Savinase.RTM.,
Kannase.RTM., Everlase.RTM., Neutrase.RTM., Flavourzyme.RTM. (all
available from Novo Nordisk, Denmark), Protex 6.0L, Peptidase FP,
Purafect.RTM., Purastar OxAm.RTM., Properase.RTM. (available from
Genencor, USA), Corolase L10 (Rohm, Germany), Pepsin (Merck,
Germany), papain, pancreatin, proleather N and Protease N (Amano,
Japan), BLAP and BLAP variants available from Henkel, K-16-like
proteases available from KAO, or combinations thereof. Table 1
describes the amino acid specificity of certain useful
endonucleases.
TABLE-US-00001 TABLE 1 No. Amino Acid Notation Commercial
Endopeptidase(s) 1 Alanine A Pronase .RTM.; Neutrase .RTM.: 2
Cysteine C Papain 3 Aspartic D Fromase .RTM.; 4 Glutamic E Alcalase
.RTM.; 5 Phenylalanine F Neutrase .RTM.: Fromase .RTM. 6 Glycine G
Flavorzyme .RTM.; Neutrase .RTM.: 7 Histidine H Properase .RTM.; 8
Isoleucine I Neutrase .RTM.: 9 Lysine K Alcalase .RTM.; Trypsin
.RTM.; Properase .RTM. 10 Leucine L Alcalase .RTM.; Esperase .RTM.;
Neutrase .RTM.: 11 Methionine M Alcalase .RTM.; Neutrase .RTM.: 12
Asparagine N Savinase .RTM.; Flavourzyme .RTM.; Duralase .RTM.; 13
Proline P Pronase .RTM.; Neutrase .RTM.: 14 Glutamine Q Alcalase
.RTM. 15 Arginine R Trypsin; Properase .RTM.; 16 Serine S Savinase
.RTM.; Flavourzyme .RTM.; Duralase .RTM.; 17 Threonine T Savinase
.RTM.; Flavourzyme .RTM.; Duralase .RTM.; 18 Valine V Neutrase
.RTM.: 19 Tryptophan W Neutrase .RTM.: Fromase .RTM. 20 Tyrosine Y
Alcalase .RTM.; Esperase .RTM.; Fromase .RTM.
[0113] Depending upon the choice of enzyme(s), enzymatic digestion
usually is conducted under aqueous conditions at the appropriate pH
conditions (for example, depending upon the enzyme or enzyme
mixture at neutral or at low pH). In certain digestion systems, the
digestion optimally occurs at a pH less than 9, or less than 8. For
certain applications the pH of the aqueous protein digestion system
is in the range of 3-9, 4-8 or 5-7.5.
[0114] Once digestion has proceeded to the desired extent, the
resulting product optionally is washed and used as is or dried to
form a powder. The drying can be performed by techniques known in
the art, including spray drying, freeze drying, oven drying, vacuum
drying, or exposure to desiccating salts (such as phosphorous
pentoxide or lithium chloride).
Chemical Modification of Proteins
[0115] In certain embodiments, the proteins in the isolated protein
fractions are further derivatized. Suitable processes for
derivatization of the polypeptide fractions are provided in the
literature. The nature and extent of modification will depend in
large part on the composition of the starting material. The
derivative can be produced by, for example, replacing at least a
portion of primary amine groups of said isolated protein with
hydroxyl groups, deaminating the protein, or replacing a portion of
amide groups of the protein with carboxyl groups, etc. In other
embodiments, the isolated polypeptide compositions described herein
are obtained by reacting the protein with protein modifying agents,
for example, nitrous oxide, nitrous acid, salts of nitrous acid, or
a combination thereof.
[0116] 2. Characterization of the Water-Insoluble/Water-Dispersible
Protein Fraction
[0117] The water-insoluble/water-dispersible protein fraction can
be characterized accordingly to multiple physical properties. For
example, the water-insoluble/water-dispersible protein fraction can
be characterized according to its capacity to disperse oil in water
or water in oil. The water-insoluble/water-dispersible protein
fraction should, at a minimum, disperse at least some oil in water
or water in oil. The amount of oil that can be dispersed in water
or the amount of water that can be dispersed in oil is a physical
property that characterizes a water-insoluble/water-dispersible
protein fraction.
[0118] The water-insoluble/water-dispersible protein fraction can
also be characterized according to i) absortion band(s) observed by
solid state FTIR, ii) molecular weight range of the proteins in the
fraction, and iii) features in a solution state, two-dimensional
proton-nitrogen coupled NMR spectrum of the fraction.
[0119] Accordingly, in certain embodiments, the
water-insoluble/water-dispersible fraction is characterized by one
or more of the following features: (i) a prominent amide-I
absorption band between about 1620 cm.sup.-1 and 1645 cm.sup.-1,
(ii) an amide-II band between approximately 1514 cm.sup.-1 and 1545
cm.sup.-1, as determined by solid state FTIR, and (iii) is capable
of dispersing an oil-in-water or water-in-oil to produce a
homogeneous emulsion that is stable for least 5 minutes.
[0120] In certain other embodiments, the
water-insoluble/water-dispersible fraction is characterized by one
or more of the following features: (i) an amide-I absorption band
between about 1620 cm.sup.-1 and 1642 cm.sup.-1 and an amide-II
band between approximately 1514 cm.sup.-1 and 1540 cm.sup.-1, as
determined by solid state FTIR, (ii) a prominent 2.degree. amide
N--H stretch absorption band centered at about 3272 cm.sup.-1, as
determined by solid state FTIR, and (iii) is capable of dispersing
an oil-in-water or water-in-oil to produce a homogeneous emulsion
that is stable for least 5 minutes.
[0121] In certain other embodiments, the
water-insoluble/water-dispersible fraction is characterized by one
or more of the following features: (i) an amide-I absorption band
between about 1620 cm.sup.-1 and 1632 cm.sup.-1 and an amide-II
band between approximately 1514 cm.sup.-1 and 1521 cm.sup.-1, as
determined by solid state FTIR, (ii) a prominent 2.degree. amide
N--H stretch absorption band centered at about 3272 cm.sup.-1, as
determined by solid state FTIR, (iii) an average molecular weight
of between about 600 and about 2,500 Daltons (determined using, for
example, MALDI mass spectrometry), (iv) two protonated nitrogen
clusters defined by .sup.15N chemical shift boundaries at about
86.2 ppm and about 87.3 ppm, and .sup.1H chemical shift boundaries
at about 7.14 ppm and 7.29 ppm for the first cluster, and .sup.1H
chemical shift boundaries at about 6.66 ppm and 6.81 ppm for the
second cluster, as determined by solution state, two-dimensional
proton-nitrogen coupled NMR.
[0122] As described above, water-insoluble/water-dispersible
fraction is capable of suspending or emulsifying oil in water or
water in oil to produce a homogeneous suspension or emulsion
stable, by visual inspection, for least 5 minutes. In certain
embodiments, the dispersion or emulsion exhibits substantially no
phase separation by visual inspection for at least 10, 15, 20, 25,
or 30 minutes, or even 1, 2, 3, 4, 5, 6, 9, 12, 18, or 24 hours
after mixing the polypeptide composition with the oil. As shown in
Example 4, the water-insoluble/water-dispersible fraction is
capable of emulsifying or dispersing a wide selection of oils,
including, for example, an organic polyisocyanate (for example,
PMDI) mineral oil, soybean oil, derivatized soybean oil, motor oil,
castor oil, derivatized castor oil, dibutyl phthalate, epoxidized
soybean oil, corn oil, vegetable oil, caprylic triglyceride,
Eucalyptus oil, and tributyl o-acetylcitrate. In an exemplary
assay, 14 parts (by weight) of a protein sample of interest is
mixed with 86 parts (by weight) of water and the resulting solution
or dispersion is mixed with 14 parts (by weight) of oil, for
example, PMDI. Under these conditions, the
water-insoluble/water-dispersible protein fraction produces a
dispersion or emulsion that exhibits substantially no phase
separation by visual inspection for at least 5 minutes after mixing
the polypeptide composition with the oil. The assay can be
performed with the other oils. Another assay that can be used
involves mixing 26 parts (by weight) of a protein sample with 74
parts (by weight) of water. The resulting solution or dispersion is
mixed with 26 parts (by weight) of oil, for example, PMDI. Under
these conditions, the water-insoluble/water-dispersible protein
fraction produces a dispersion or emulsion that exhibits
substantially no phase separation by visual inspection for at least
5 minutes after mixing the polypeptide composition with the oil.
This assay using 26 parts (by weight) of a protein can be performed
with oils other than PMDI, such as the oils described above in
connection with the assay using 14 parts (by weight) of protein
sample.
[0123] In certain other embodiments, the
water-insoluble/water-dispersible fraction is further characterized
by its ability to emulsify or disperse, in water, one or more of
the following hydrophobic liquids and hydrophobic solids: a
silicone (e.g., a silicone oil or a silicone gel), a fluorocarbon
(e.g., a solid wax fluorocarbon or a liquid oil fluorocarbon), a
fluorinated polyol, a wax (e.g., a solid carboxylic acid ester
(e.g., an ester of stearic acid), a salt of a carboxylic acid
(e.g., a salt of stearic acid, e.g., zinc stearate), a hydrocarbon
wax, and a fluorinated hydrocarbon wax), a liquid carboxylic acid
ester that is hydrophobic, and a liquid hydrocarbon.
[0124] In yet other embodiments, the
water-insoluble/water-dispersible fraction is further characterized
by its ability to emulsify or disperse one or more of the following
agents in water: BE Square 165 Amber Petroleum Microcrystalline Wax
from Baker Hughes, Inc.; limonene; FluoroLink D-10 Fluorinated
polyol from Solvay Solexis, Inc; Tego Protect-5000 functionalized
silicone fluid from Evonik Tego Chemie GmbH; Soy Lecithin; Castor
Oil; Zinc Stearate; Dow Corning FS-1265 Fluid, 300 cST
(Trifluoropropyl Methicone) from Dow Corning; and T-Sil-80, hydroxy
terminated polydimethylsiloxane from Siovation, Inc.
[0125] In yet other embodiments, the
water-insoluble/water-dispersible fraction is further characterized
by its ability to emulsify or disperse an amalgam comprising a
partially exfoliated clay in an oil carrier. In yet other
embodiments, the water-insoluble/water-dispersible fraction is
further characterized by its ability to emulsify or disperse a
melted wax in water. In certain embodiments, the dispersion or
emulsion exhibits substantially no phase separation by visual
inspection for at least 10, 15, 20, 25, or 30 minutes, or even 1,
2, 3, 4, 5, 6, 9, 12, 18, or 24 hours after mixing the polypeptide
composition with the agent.
[0126] In certain embodiments, the
water-insoluble/water-dispersible fraction is substantially free of
primary amines, carboxylic acids, amine salts, and carboxylate
salts.
[0127] The water-insoluble/water-dispersible protein fraction can
act as a surfactant to an organic polyisocyanate (e.g., PMDI),
lowering interfacial tension to the point where the water insoluble
organic polyisocyante is readily emulsified with minimal energy
input, creating an oil-in-water or water-in-oil emulsion. When the
source material is a whole meal or a protein isolate derived from
soy, castor or canola, a stable emulsion can be obtained using
undigested substantially insoluble (fractionated) protein. In
certain embodiments, a stable emulsion of polyisocyanate (e.g.,
PMDI) in water can be achieved when the isolated fractionated
polypeptide is comprised of a water-insoluble/water-dispersible
fraction, either alone, or in combination with a water soluble
component. The acceptable level of the water-soluble component will
depend in large part upon the adhesive performance characteristics
that are needed for the end-use application.
[0128] Under certain circumstances, for example, an adhesive
prepared with digested castor protein extracted from castor meal,
the process of isolating and digesting a protein can lead to a
polypeptide composition that implicitly contains both water-soluble
and water-insoluble fractions at ratios sufficient to
simultaneously disperse oil in water. The process of digesting a
whole meal can lead to a mixture that includes a polypeptide
composition that implicitly contains both water-soluble and
water-insoluble fractions at ratios sufficient to simultaneously
disperse oil in water. Where the process of digestion or extraction
does not lead to a polypeptide composition that implicitly
comprises both water-soluble and water-insoluble fractions at
ratios which are sufficient to simultaneously disperse oil in water
while yielding high bond strength adhesives, an additional
fractionation step can be used to isolate sufficient levels of the
water-insoluble/water-dispersible fraction from the polypeptide
composition, so that the ratio of the water-insoluble fraction to
the water-soluble fraction can be adjusted in the formulated
adhesive for the purpose of achieving the desired combination of
end-use properties. In certain embodiments, it may be desirable to
obtain an isolated polypeptide composition containing very little
or no water-soluble protein fraction, such as through water washing
of plant meal, optimization of the Acid Precipitation Method, or
enzymatic digestion to reduce the amount of water-soluble
protein.
[0129] The isolated polypeptide composition obtained using the
Water Washing Method may contain a mixture of i)
water-insoluble/water-dispersible protein fraction and ii)
water-soluble protein fraction. Depending on the composition of the
protein source material (e.g., soy meal, castor meal, or canola
meal), the isolated polypeptide composition obtained using the
Water Washing Method may contain a sufficient amount of
water-insoluble/water-dispersible protein fraction to disperse oil
or water. If, however, the isolated polypeptide composition
obtained using the Water Washing Method contains insufficient
water-insoluble/water-dispersible protein fraction, then higher
purity water-insoluble/water-dispersible protein fraction obtained
from the Acid Precipitation Method can be added to the isolated
polypeptide composition in order to increase the relative amount of
water-insoluble/water-dispersible protein fraction.
[0130] In certain embodiments, the polypeptide fractions used in
the compositions and methods provided herein, can have a weight
average molecular weight of between about 500 and 25,000 Daltons.
Useful polypeptide fractions can have a weight average molecular
weight of between about 500 and 2,500 Daltons, between about 700
and 2,300 Da., between about 900 and 2,100 Da., between about 1,100
and 1,900 Da., between about 1,300 and 1,700 Da., or between about
1,000 and 1,300 Da., between about 2,000 and 2,500 Da., or between
about 1,000 and 2,500 Da.
[0131] In certain embodiments, the
water-insoluble/water-dispersible protein fraction provides a
stable emulsion, dispersion or suspension, for example, an aqueous
emulsion, dispersion or suspension, comprising from about 1% to
about 90% (w/w) of an oil and from about 1% to about 99% (w/w) of
an isolated polypeptide composition, wherein the isolated
polypeptide composition produces a stable emulsion or dispersion of
the oil in an aqueous medium. The aqueous emulsion, dispersion or
suspension optionally comprises from about 1% to about 50% (w/w) of
oil and from about 1% to about 99% (w/w) of the isolated
polypeptide composition. The term "stable" when used in reference
to the emulsions, suspensions and dispersions refers to the ability
of the polypeptide fraction described herein to create a
kinetically stable emulsion for the duration of the intended
application of the dispersion or emulsion. The terms "emulsion,"
"dispersion," and "suspension" are used interchangeably herein.
[0132] In certain embodiments, the polypeptide composition has a
polydispersity index (PDI) of between about 1 and 1.15. In certain
embodiments, the PDI of the adhesives provided created using the
polypeptides described herein is between about 1 and about 3,
between 1 and 1.5, between 1.5 and 2, between 2 and 2.5, between
2.5 and 3, between 1 and 2, between 1.5 and 2.5, or between 2 and
3.
[0133] 3. Characterization of Water-Soluble Protein Fraction
[0134] The water-soluble protein fractions, for example, the
water-soluble protein fractions isolated pursuant to the protocol
set forth in FIG. 1, are substantially or completely soluble in
water.
[0135] The water-soluble protein fractions have one or more of the
following six features. (i) An amide-I absorption band between
about 1633 cm.sup.-1 and 1680 cm.sup.-1, as determined by solid
state FTIR. (ii) An amide-II band between approximately 1522
cm.sup.-1 and 1580 cm.sup.-1, as determined by solid state FTIR.
(iii) Two prominent 1.degree. amide N--H stretch absorption bands
in the range of from about 3100-3200 cm.sup.-1, and in the range of
from about 3300-3400 cm.sup.-1, as determined by solid state FTIR.
(iv) A prominent cluster of protonated nitrogen nuclei defined by
.sup.15N chemical shift boundaries at about 94 ppm and about 100
ppm, and .sup.1H chemical shift boundaries at about 7.6 ppm and 8.1
ppm, as determined by solution state, two-dimensional
proton-nitrogen coupled NMR. (v) An average molecular weight of
between about 600 and about 2,500 Daltons, for example, as
determined by MALDI. (vi) An inability to stabilize an oil-in-water
or water-in-oil dispersion or emulsion, where the water and oil
components of the mixture form an unstable suspension that
macroscopically phase separates under static conditions within five
minutes after mixing. This can be tested by dissolving or
dispersing 14 parts (by weight) of a protein sample of interest in
86 parts (by weight) of water and then mixing the resulting
solution with 14 parts (by weight) of oil, for example, PMDI. Under
these conditions, a water-soluble protein is characterized by an
inability to stabilize an oil-in-water emulsion, where the oil and
water components form an unstable suspension that macroscopically
phase separates under static conditions within five minutes after
mixing. Another procedure for evaluating the inability of a protein
sample to stabilize an oil-in-water or water-in-oil dispersion or
emulsion is to mix 26 parts by weight of a water-soluble
protein-containing fraction isolated from whole ground meal in 74
parts (by weight) of water, and then mix the resulting solution
with 26 parts (by weight) of oil, for example, PMDI. Under these
conditions, a water-soluble protein-containing fraction is
characterized by an inability to stabilize an oil-in-water
emulsion, where the oil and water components form an unstable
suspension that macroscopically phase separates under static
conditions within five minutes after mixing.
VII. Reactive Prepolymer
[0136] The adhesive compositions may optionally comprise a reactive
prepolymer. The term "prepolymer" is understood to mean a compound,
material or mixture that is capable of reacting with a plant
protein composition described herein to form an adhesive polymer.
Exemplary prepolymers include, for example, isocyanate-based
prepolymers, epoxy-based prepolymers, and latex prepolymers.
Further exemplary prepolymers include an organic polyisocyanate; a
reaction product between an organic polyisocyanate and a
polypeptide, a polyol, an amine based polyol, an amine containing
compound, a hydroxy containing compound, or a combination thereof;
an epoxy containing compound; a reaction product between an epoxy
containing compound and a polypeptide, a polyol, an amine based
polyol, an amine containing compound, a hydroxy containing
compound, or a combination thereof; an organosilane; a polymer
latex; a polyurethane; and a mixture thereof.
[0137] The term "prepolymer" includes full prepolymers and partial
prepolymers (referred to as semiprepolymers, pseudoprepolymers, or
quasiprepolymers in certain embodiments). One example of a quasi
prepolymer is a NCO-terminated product prepared from a diisocyanate
and polyol in which the prepolymer is a mixture of (i) a product
prepared from the diisocyanate and polyol, and (ii) unreacted
diisocyanate. On the other hand, an example of a full prepolymer is
the product formed by reacting an isocyanate with a particular
polyol blend so that there are substantially no residual monomeric
isocyanates in the finished product.
[0138] An isocyanate-based prepolymer can be an organic
polyisocyanate, which can be (i) a polyisocyanate (or monomeric
diisocyanate) that has not been reacted with another compound, (ii)
a polyisocyanate modified by various known self-condensation
reactions of polyisocyanates, such as carbodiimide modification,
uretonimine modification, trimer (isocyanurate) modification or a
combination thereof, so long as the modified polyisocyanate still
contains free isocyanate groups available for further reaction, or
(iii) the product formed by reaction of a polyisocyanate base with
a compound having nucleophilic functional groups capable of
reacting with an isocyanate group. Exemplary compounds containing a
nucleophilic functional group capable of reacting with an
isocyanate group include a polypeptide (for example, one or more of
the protein fractions described herein), a polyol, an amine based
polyol, an amine containing compound, a hydroxy containing
compound, carboxylic acid containing compound, carboxylate salt
containing compound, or a combination thereof. The term
"polyisocyanate" refers to difunctional isocyanate species, higher
functionality isocyanate species, and mixtures thereof.
[0139] One desirable feature of an isocyanate-based prepolymer is
that the prepolymer remain stable enough for storage and use,
desirably liquid and of reasonable viscosity at ambient
temperatures (25.degree. C.), and contains free isocyanate (--NCO)
groups which can participate in forming adhesive bonds.
[0140] As noted above, the organic polyisocyanate can be prepared
from a "base polyisocyanate." The term "base isocyanate" as used
herein refers to a monomeric or polymeric compound containing at
least two isocyanate groups. The particular compound used as the
base polyisocyanate can be selected so as to provide an adhesive
having certain desired properties. For example, base polyisocyanate
can be selected based on the number-average isocyanate
functionality of the compound. For example, in certain embodiments,
the base polyisocyanate can have a number-average isocyanate
functionality of 2.0 or greater, or greater than 2.1, 2.3 or 2.4.
In certain embodiments, the reactive group functionality of the
polyisocyanate component ranges from greater than 1 to several
hundred, 2 to 20, or 2 to 10. In certain other embodiments, the
reactive group functionality of the polyisocyanate component is at
least 1.9. In certain other embodiments, the reactive group
functionality of the polyisocyanate component is about 2. Typical
commercial polyisocyanates (having an isocyanate group
functionality in the range of 2 to 3) may be pure compounds,
mixtures of pure compounds, oligomeric mixtures (an important
example being polymeric MDI), and mixtures of these.
[0141] Useful base polyisocyanates have, in one embodiment, a
number average molecular weight of from about 100 to about 5,000
g/mol, from about 120 to about 1,800 g/mol, from about 150 to about
1,000 g/mol, from about 170 to about 700 g/mol, from about 180 to
about 500 g/mol, or from about 200 to about 400 g/mol. In certain
other embodiments, at least 80 mole percent or, greater than 95
mole percent of the isocyanate groups of the base polyisocyanate
composition are bonded directly to an aromatic group. In certain
embodiments, the adhesives described herein have a concentration of
free organically bound isocyanate (--NCO) groups in the range of
from about 5% to 35% (wt/wt), about 7% to 31% (wt/wt), 10% to 25%
(wt/wt), 10% to 20% (wt/wt), 15% to 27% (wt/wt).
[0142] In certain embodiments, the base polyisocyanate is an
aromatic polyisocyanate, such as p-phenylene diisocyanate;
m-phenylene diisocyanate; 2,4-toluene diisocyanate; 2,6-toluene
diisocyanate; naphthalene diisocyanates; dianisidine diisocyanate;
polymethylene polyphenyl polyisocyanates; 2,4'-diphenylmethane
diisocyanate (2,4'-MDI); 4,4'-diphenylmethane diisocyanate
(4,4'-MDI); 2,2'-diphenylmethane diisocyanate (2,2'-MDI);
3,3'-dimethyl-4,4'-biphenylenediisocyanate; mixtures of these; and
the like. In certain embodiments, polymethylene polyphenyl
polyisocyanates (MDI series polyisocyanates) having a number
averaged functionality greater than 2 are utilized as the base
polyisocyanate.
[0143] In certain embodiments, the MDI base polyisocyanate
comprises a combined 2,4'-MDI and 2,2'-MDI content of less than
18.0%, less than 15.0%, less than 10.0%, or less than 5.0%.
[0144] In certain other embodiments, the MDI diisocyanate isomers,
mixtures of these isomers with tri- and higher functionality
polymethylene polyphenyl polyisocyanates, the tri- or higher
functionality polymethylene polyphenyl polyisocyanates themselves,
and non-prepolymer derivatives of MDI series polyisocyanates (such
as the carbodiimide, uretonimine, and/or isocyanurate modified
derivatives) are utilized as polyisocyanates for use as the base
polyisocyanate. In certain other embodiments, the base
polyisocyanate composition comprises an aliphatic polyisocyanate
(e.g., in a minor amount), e.g., an aliphatic polyisocyanate
comprising an isophorone diisocyanate, 1,6-hexamethylene
diisocyanate, 1,4-cyclohexyl diisocyanate, or saturated analogues
of the above-mentioned aromatic polyisocyanates, or mixtures
thereof.
[0145] In certain other embodiments, the base polyisocyanate
comprises a polymeric polyisocyanate, e.g., a polymeric
diphenylmethane diisocyanate (polymethylene polyphenyl
polyisocyanate) species of functionality 3, 4, 5, or greater. In
certain embodiments, the polymeric polyisocyanates of the MDI
series comprise RUBINATE-M.RTM. polyisocyanate, or a mixture of MDI
diisocyanate isomers and higher functionality oligomers of the MDI
series. In certain embodiments, the base polyisocyanate product has
a free --NCO content of about 31.5% by weight and a number averaged
functionality of about 2.7.
[0146] In certain embodiments, the isocyanate group terminated
prepolymers are urethane prepolymers. These can be produced by
reaction of a hydroxyl-functional compound with an isocyanate
functional compound. In certain other embodiments, allophanate
prepolymers are utilized. Allophanate prepolymers typically require
higher temperatures (or allophanate catalysts) to facilitate
reaction of the polyol with the polyisocyanate to form the
allophanate prepolymer.
[0147] Polyisocyanates used in the compositions described can have
the formula R(NCO).sub.n. where n is 2 and R can be an aromatic, a
cycloaliphatic, an aliphatic, each having from 2 to about 20 carbon
atoms. Examples of polyisocyanates include, but are not limited to,
diphenylmethane-4,4'-diisoeyanate (MDI), toluene-2,4-diisocyanate
(TDI), toluene-2,6-diisocyanate (TDI), methylene
bis(4-cyclohexylisocyanate (CHMDI),
3-isocyanatomethyl-3,5,5-trimethyl-cyclohexyl isocyanate (IPDI),
1,6-hexane diisocyanate (HDl), naphthalene-1,5-diisocyanate (NDI),
1,3- and 1,4-phenylenediisocyanate,
triphenylmethane-4,4',4''-triisocyanatc, polymeric diphenylmethane
diisocyanate (PMDI), m-xylene diisocyanate (XDI), 1,4-cyclohexyl
diisocyanate (CHDl), isophorone diisocyanate, isomers, dimers,
trimers and mixtures or combinations of two or more thereof. The
term "PMDI" encompasses PMDI mixtures in which monomeric MDI, for
example 4,4'-, 2,2'- and/or 2,4'-MDI, is present. PMDI is, in one
embodiment, prepared by phosgenation of the corresponding PMDA in
the presence of an inert organic solvent. PMDA is in turn obtained
by means of an acid aniline-formaldehyde condensation which can be
carried out industrially either continuously or batchwise. The
proportions of diphenylmethanediamines and the homologous
polyphenylpolymethylenepolyamines and their positional isomerism in
the PMDA are controlled by selection of the ratios of aniline,
formaldehyde and acid catalyst and also by means of a suitable
temperature and residence time profile. High contents of
4,4'-diphenylmethanediamine together with a simultaneously low
proportion of the 2,4' isomer of diphenylmethanediamine are
obtained on an industrial scale by the use of strong mineral acids
such as hydrochloric acid as catalyst in the aniline-formaldehyde
condensation.
[0148] Accordingly, in certain more specific embodiments, the
reactive prepolymer is a polyisocyanate-based prepolymer, an
epoxy-based prepolymer, a latex-based prepolymer, a latex
prepolymer, or a combination thereof. In certain other embodiments,
the reactive prepolymer is a polyisocyanate-based prepolymer. In
certain other embodiments, the polyisocyanate-based prepolymer is
an organic polyisocyanate; or a reaction product between an organic
polyisocyanate and a polypeptide, a polyol, an amine based polyol,
an amine containing compound, a hydroxy containing compound, or a
combination thereof. In certain other embodiments, the reactive
prepolymer is polymeric diphenylmethane diisocyanate.
[0149] The epoxy-based prepolymer can be an epoxide containing
compound. Alternatively, the epoxy-based prepolymer can be a
reaction product between an epoxy and a polypeptide, a polyol, an
amine based polyol, an amine containing compound, a hydroxy
containing compound, or a combination thereof.
[0150] In certain embodiments, the composition is an epoxy resin
comprising free epoxy groups. Alternatively, the epoxy resin
composition is prepared by combining a precursor epoxy resin
composition with the isolated and fractionated polypeptide
compositions described herein. The epoxy resin composition can
comprise derivatives of digested proteins as described herein.
[0151] Epoxy resins refer to molecular species comprising two or
more epoxide (oxirane) groups per molecule. Epoxy resins can
contain mono-epoxides as reactive diluents, but the main
constituents by weight of such resins are still di- and/or higher
functionality species (containing two or more epoxide groups per
molecule).
[0152] Epoxy resins useful as precursor epoxy resins can include
those which comprise difunctional epoxide and/or higher
functionality polyepoxide species. Precursor epoxy resins include
but are not limited to diglycidyl ether of bisphenol-A, diglycidyl
ethers of bisphenol-A alkoxylates, epoxy novolac resins,
expoxidized soy oil, epoxidized linseed oil, epichlorohydrin, a
glycidyl ether type epoxy resin derived from a polyphenol by
reaction with epichlorohydrin, and combinations thereof. In another
embodiment, precursor epoxy resins are modified by combining them
with the polypeptide compositions described herein, either in bulk
or in aqueous suspension.
[0153] The modified epoxy resins can be used in multi-part
mixing-activated adhesive formulations. Alternatively, multi-part
formulations can comprise polyisocyanates and/or known amine based
epoxy curatives as additional components. Alternatively, modified
epoxy resins can be used with any cure catalysts or other additives
known in the epoxy resin art. The polypeptide compositions
described herein contain functional groups which react with epoxide
groups in the epoxy resin. The extent of this reaction depends upon
the preparative conditions, use or non-use of catalysts, the
specific resins and protein component described herein selected,
etc.
[0154] An important subset of epoxy resins can be made by reacting
a precursor polyol with an epihalohydrin, such as epichlorohydrin.
The products of the reaction are called glycidyl ethers (or
sometimes as polyglycidyl ethers or diglycidyl ethers). In certain
embodiments, all the hydroxyl groups in the precursor polyols are
converted to the corresponding glycidyl ethers.
[0155] An important class of glycidyl ether type epoxy resins are
derived from polyphenols, by reaction with epichlorohydrin. The
starting polyphenols are di- or higher functionality phenols.
Industrially important examples of this type of epoxy resin
comprise, for example, diglycidyl ether of bisphenol-A (also known
as DGEB-A); diglycidyl ether of 2,6,2',6'-tetrachloro bisphenol A;
diglycidyl ether of bisphenol-F (DGEB-F); epoxidized novolac
resins; mixtures of these, and the like.
[0156] Partially or fully saturated (hydrogenated) analogs of these
epoxy resins may also be used. A non limiting example of a known
saturated epoxy resin of this type is DGEB-H, which is the fully
hydrogenated (ring saturated) aliphatic analog of DGEB-A.
[0157] Amines, which contain active hydrogen atoms may also be
reacted with epichlorohydrin to form epoxy resins. Examples of
these types of resins include, for example, N,N,N',N'-tetraglycidyl
diphenylmethane diamine (such as the 4,4' isomer);
p-glycidyloxy-N,N-diglycidylaniline; N,N-diglycidylaniline;
mixtures of these; and the like.
[0158] Heterocyclic nitrogen compounds that contain active hydrogen
atoms may likewise be converted into the corresponding epoxy resins
by reaction with epichlorohydrin. Non limiting examples of such
resins include, for example, N,N',N''-triglycidyl isocyanurate;
N,N'-diglycidyl-5,5-dimethylhydantoin; mixtures of these; and the
like.
[0159] Many other kinds of epoxy resins are known which are not
made by reaction of an active hydrogen precursor with an
epihalohydrin. Non-limiting examples of these types of epoxy
resins, known in the art, include, for example, dicyclopentadiene
diepoxide (also known as DCPD dioxide), vinycyclohexene diepoxide
(dioxide), epoxidized polyunsaturated vegetable oils (such as
epoxidized linseed oil, epoxidized soy oil, etc.), epoxidized
polydiene resins (such as epoxidized polybutadienes),
3,4-epoxy-6-methyl cyclohexylmethyl-3,4-epoxy-6-methyl cyclohexane
carboxylate, mixtures of these, and the like. In principle, any
precursor molecule which contains two or more units of reactive
aliphatic "C.dbd.C" unsaturation per molecule might be converted
into an epoxy resin.
[0160] It should be understood that any of the base epoxy resins
known in the art, such as those listed above, are frequently
modified with diluents, flexibilizers, and/or other additives. The
optional possibility of using one or more known art modifiers or
additives, in addition to the required protein derivatives, is
within the level of skill in the art. Those skilled in the art of
formulating adhesive systems using epoxy resins will appreciate how
and when to use known optional additives and modifiers.
[0161] In addition, the prepolymers can include one, two or more
polyol compounds. Exemplary polyol compounds include an amine
alkoxylate, polyoxypropylene glycol, propylene glycol,
polyoxyethylene glycol, polytetramethylene glycol, polyethylene
glycol, propane diol, glycerin, or a mixture thereof.
[0162] Polyols useful in preparing the adhesives described herein
include all known polyols, for example, polyols used in the
polyurethanes art. In certain embodiments, the polyol comprises
primary and/or secondary hydroxyl (i.e., --OH) groups. In certain
other embodiments, the polyol comprises at least two primary and/or
secondary hydroxyl (i.e., --OH) groups per molecule. Mono
functional alcohols (such as aliphatic alcohols, aromatic alcohols,
or hydroxyl functional monomers such as hydroxyl functional
acrylates (to yield UV or thermally curable materials) can be used
to cap an isocyanate group. In certain other embodiments, the
polyol comprises a hydroxyl (i.e., --OH) group functionality
between 1.6 and 10, between 1.7 to 6, between 2 to 4, or between 2
to 3. In certain other embodiments, the weight average molecular
weight range for the optional polyols is from 100 to 10,000 g/mol,
from 400 to 6,000 g/mol, or from 800 to 6,000 g/mol.
[0163] In certain other embodiments, useful polyols are polyester
polyols or polyether polyols, such as an aliphatic polyether
polyol. One exemplary aliphatic polyether polyol is
polyoxypropylene glycol, with a number average molecular weight in
the range of from 1,500 to 2,500 g/mol.
[0164] In certain embodiments, the total amount of all polyol, or
polyols, in the isocyanate reactive component is from 1% to 80%, or
from 3% to 70%, or from 5% to 60% by weight of the total.
[0165] In certain other embodiments, alkanolamines comprising
primary, secondary, and/or tertiary amine groups can be used.
[0166] In certain embodiments, useful water-dispersible polymer
latexes can include latexes of polymethylmethacrylate and its
copolymers, latexes of polymethacrylate and its copolymers, latexes
of polyvinylchloride and its copolymers, latexes of
polyvinylacetate and its copolymers, polyvinyl alcohol and its
copolymers, etc.
[0167] Further, as discussed above, the prepolymer species can
comprise a terminated isocyanate. Here, for example, a polyol is
reacted with the base polyisocyanate composition prior to or during
mixing with the polypeptide fractions herein. Those skilled in the
art will recognize many variations on the use of optional
prepolymers in preparing wood adhesive compositions.
[0168] The amount of reactive prepolymer used in the adhesive
compositions can be selected based on the desired properties of the
adhesive composition. For example, when optimizing the viscosity of
a one-part adhesive, the ratio of prepolymer (e.g., PMDI, Epoxy and
the like) to protein component (i.e., ground plant meal or isolated
polypeptide composition) can be from about 10:1 and 4:1 in order to
form an adhesive composition that is relatively less viscous.
VIII. Additives
[0169] One or more additives can be included in the adhesive
composition in order to achieve particular performance properties.
Exemplary additives include an intercalated clay, partially
exfoliated clay, exfoliated clay, cellulose nanoparticles,
catalysts, tacking agents, extenders, fillers, viscosifying agents,
surfactants, adhesion promoters, antioxidants, antifoaming agents,
antimicrobial agents, antibacterial agents, fungicides, pigments,
inorganic particulates, gelling agents, cross-linking agents,
agents that improve moisture resistance, pH modulators,
composite-release promoters, fire retardants, and wood
preservatives.
[0170] In certain embodiments, the additive is a water-dispersible
additive or a water-soluble additive. Water-soluble additives
include hydroxyl-functional or amine-functional compounds (such as
glycerin, propylene glycol, polypropylene glycol, polyethylene
glycol, trimethylol propane and its adducts, phenols, polyphenols,
etc.). One benefit of using glycerin and various low-viscosity
polyols is that they allow less water to be used in the adhesive
composition. Reducing the amount of water, while retaining a
low-viscosity adhesive composition, desirably reduces the risk that
the composite formed therefrom is damaged by steam generated during
formation of the composite at high temperature.
[0171] In certain other embodiments, the additive is a non-volatile
(e.g., having a boiling point of greater than about 180.degree. C.
at 760 mmHg), inert viscosity-reducing diluent. In yet other
embodiments, the additive is an antioxidant, antifoaming agent,
anti-bacterial agent, fungicide, pigment, viscosifying agent,
gelling agent, aereosolozing agent, inorganic particulate (e.g.,
titanium dioxide, yellow iron oxide, red iron oxide, black iron
oxide, zinc oxide, aluminum oxide, aluminum trihydrate, calcium
carbonate), clay such as montmorillonite, a wetting agent, and the
like.
[0172] In certain embodiments, the additive is an agent that
improves moisture-resistance. In certain other embodiments, the
additive is a composite-release promoter (such as a
composite-release promoter selected from the group consisting of a
C.sub.10-25 alkanoic acid, a salt of a C.sub.10-25 alkanoic acid, a
C.sub.10-25 alkenoic acid, a salt of an C.sub.10-25 alkenoic acid,
and a silicone). In certain other embodiments, the additive is a pH
modulator. In certain other embodiments, the additive is a fire
retardant or wood preservative. In certain other embodiments, the
additive is a fire retardant, wood preservative, antimicrobial
agent, antibacterial agent, or fungicide, any of which may be in
the form of nanoparticles.
[0173] Exemplary classes of additives are described in more detail
in the sections below.
Intercalated Clay
[0174] Intercalated clays can be obtained from commercial sources
or prepared by exposing a clay to an intercalating agent. Exemplary
types of clay that may be converted to intercalated form include,
for example, smectite clays, illite clays, chlorite clays, layered
polysilicates, synthetic clays, and phyllosilicates. Exemplary
specific clays that may be converted to intercalated form include,
for example, montmorillonite (e.g., sodium montmorillonite,
magnesium montmorillonite, and calcium montmorillonite),
beidellite, pyrophyllite, talc, vermiculite, sobockite, stevensite,
svinfordite, sauconite, saponite, volkonskoite, hectorite,
nontronite, kaolinite, dickite, nacrite, halloysite, hisingerite,
rectorite, tarosovite, ledikite, amesite, baileychlore, chamosite,
clinochlore, kaemmererite, cookeite, corundophilite, daphnite,
delessite, gonyerite, nimite, odinite, orthochamosite, penninite,
pannantite, rhipidolite, prochlore, sudoite, thuringite, kanemite,
makatite, ilerite, octosilicate, magadiite, and kenyaite. In
certain embodiments, the clay converted to intercalated form is
montmorillonite.
[0175] Exemplary intercalating agents include, for example,
quaternary amine compounds (such as a tetra-alkylammoniun salt),
polymers (e.g., a polycaprolactone, maleated polyethylene, or
maleated polypropylene) an acrylic monomer, phosphonium compounds,
arsonium compounds, stibonium compounds, oxonium compounds,
sulfonium compounds, polypropene, fatty acid esters of
pentaerythritol, a steroyl citric acid ester, and alcohols (such as
aliphatic alcohols, aromatic alcohols (e.g., phenols), aryl
substituted aliphatic alcohols, alkyl substituted aromatic
alcohols, and polyhydric alcohols).
[0176] Intercalated clays can be characterized by, for example, the
following physical properties: interlayer spacing, d-spacings, clay
particle size, particle size distribution, peak degradation
temperature, and thickness of layers. Exemplary physical property
features for intercalated clays contemplated to be amenable for use
in the present invention include, for example, one or more of the
following: (i) an intercalated clay having an interlayer spacing of
about 0.5 .ANG. to about 100 .ANG. (or about 1 .ANG. to about 20
.ANG.), (ii) a mean particle size of about 1 .mu.m to about 150
.mu.m (or about 20 .mu.m to about 100 .mu.m), (iii) a particle size
distribution where about 90 percent to about 50 percent of the
intercalated clay particles have a particle size of from about 20
.mu.m to about 100 .mu.m (or about 85 percent to about 65 percent
of the intercalated clay particles have a particle size of about 20
.mu.m to about 100 .mu.m), (iv) a peak degradation temperature of
about 200.degree. C. to about 600.degree. C. (or from about
300.degree. C. to about 500.degree. C.), and (v) layers in the
intercalated clay have a thickness of about 0.5 .ANG. to about 100
.ANG. (or about 5 .ANG. to about 50 .ANG.).
[0177] In certain other embodiments, the intercalated clay is
intercalated montmorillonite having a particle size of less than
about 500 nm, or less than about 100 nm. In certain other
embodiments, the intercalated clay is intercalated montmorillonite
having a particle size of about 60 nm to about 400 nm.
[0178] The clay (e.g., an intercalated clay) may be surface treated
with an organic compound, such as a hydrophobic organic compound or
hydrophilic organic compound, in order to promote dispersion of the
clay in a formulation, such as an adhesive composition described
herein. Surface treatment methods and compositions are described in
the literature and are contemplated to be amenable for use in the
present invention.
[0179] Different intercalated clays may impart different
performance properties to the adhesive composition. Accordingly, in
certain embodiments, the intercalated clay is an intercalated
smectite. In certain other embodiments, intercalated clay is a
smectite that has been intercalated with a quaternary ammonium
compound. In certain other embodiments, the intercalated clay is an
intercalated montmorillonite. In yet other embodiments, the
intercalated clay is montmorillonite intercalated with a
dimethyl-di(C.sub.14-C.sub.18)alkyl ammonium salt.
Exfoliated Clay & Partially Exfoliated Clay
[0180] Exfoliated clay or a partially exfoliated clay can be
prepared by exposing an intercalated clay to exfoliation conditions
using procedures described in the literature. One procedure for
preparing a partially exfoliated clay is to subject an intercalated
clay to high shear mixing and/or sonication (e.g., using
ultrasound) until the intercalated clay has partially exfoliated.
The procedure may be performed by placing the intercalated clay
(e.g., quaternary amine intercalated montmorillonite) in a
hydrophobic liquid medium (such as mineral oil, soy oil, castor
oil, silicone oil, a terpene (e.g., limonene), plant oil alkyl
esters (e.g., soy methyl ester and canola methyl ester), mixtures
thereof (e.g., a mixture of a silicone oil and limonene), etc.) to
form a mixture, and then subjecting the mixture to high shear
mixing and/or ultrasound until the intercalated clay has partially
exfoliated. Partial exfoliation occurs when clay platelets separate
from the intercalated clay particles. Partial exfoliation can be
observed macroscopically in many instances because it can cause a
low viscosity mixture of intercalated clay and hydrophobic liquid
medium to form a gel. This gel can be added to protein adhesives or
components used to form a protein adhesive described herein.
Alternatively, the intercalated clay may be added to a protein
adhesive composition, and the protein adhesive composition is
subjected to exfoliation conditions to generate the partially
exfoliated clay in situ.
[0181] An exfoliated clay can be prepared by exposing an
intercalated clay to high shear mixing and/or sonication (e.g.,
using ultrasound) until substantially all (e.g., greater than 90%
w/w, 95% w/w, or 98% w/w) the intercalated clay has exfoliated. The
exfoliation procedure can be performed by placing the intercalated
clay (e.g., quaternary amine intercalated montmorillonite) in a
hydrophobic liquid medium (such as mineral oil, soy oil, castor
oil, silicone oil, a terpene (e.g., limonene), plant oil alkyl
esters (e.g., soy methyl ester and canola methyl ester), mixtures
thereof (e.g., a mixture of a silicone oil and limonene), etc.) to
form a mixture, and then subjecting the mixture to high shear
mixing and/or sonication (e.g., using ultrasound) until
substantially all the intercalated clay has exfoliated.
Alternatively, the intercalated clay may be added to a protein
adhesive composition, and the protein adhesive composition is
subjected to exfoliation conditions to generate the exfoliated clay
in situ. Alternatively, a clay (such as sodium montmorrilonite) may
be added to an adhesive composition, together with a quaternary
ammonium compound, and optionally together with a satisfactory oil
carrier (e.g., one that has the ability to solvate the quaternary
compound), and the resulting adhesive composition is subjected to
conditions to intercalate the clay and to generate the exfoliated
clay or partially exfoliated clay in situ. In addition, if so
desired, the quaternary ammonium compound can be pre-dissolved in
the oil carrier before it is added to the adhesive composition
together with a clay.
[0182] Exemplary partially exfoliated clays contemplated to be
amenable for use in present invention include partially exfoliated
forms of smectite clay, illite clay, chlorite clay, layered
polysilicates, synthetic clay, and phyllosilicates. Exemplary
specific partially exfoliated clays contemplated to be amenable for
use in present invention include partially exfoliated forms of, for
example, montmorillonite (e.g., sodium montmorillonite, magnesium
montmorillonite, and calcium montmorillonite), beidellite,
pyrophyllite, talc, vermiculite, sobockite, stevensite,
svinfordite, sauconite, saponite, volkonskoite, hectorite,
nontronite, kaolinite, dickite, nacrite, halloysite, hisingerite,
rectorite, tarosovite, ledikite, amesite, baileychlore, chamosite,
clinochlore, kaemmererite, cookeite, corundophilite, daphnite,
delessite, gonyerite, nimite, odinite, orthochamosite, penninite,
pannantite, rhipidolite, prochlore, sudoite, thuringite, kanemite,
makatite, ilerite, octosilicate, magadiite, and kenyaite. In
certain embodiments, the partially exfoliated clay is partially
exfoliated clay montmorillonite.
[0183] A partially exfoliated clay can be characterized by, for
example, the amount of clay particles that are in the form of
platelets. In certain embodiments, about 0.1% w/w to about 40% w/w,
about 0.1% w/w to about 20% w/w, about 0.1% w/w to about 10% w/w,
about 0.1% w/w to about 5% w/w, or about 5% w/w to about 20% w/w of
the clay particles are in the form of platelets. In certain
embodiments, about 0.1% w/w to about 40% w/w of the clay particles
are in the form of platelets having a size of about 1 .ANG. to
about 50 .ANG., about 30 .ANG. to about 50 .ANG., or about 5 .ANG.
to about 20 .ANG..
[0184] Exemplary exfoliated clays contemplated to be amenable for
use in present invention include exfoliated forms of smectite clay,
illite clay, chlorite clay, layered polysilicates, synthetic clay,
and phyllosilicates. Exemplary specific exfoliated clays
contemplated to be amenable for use in present invention include
exfoliated forms of, for example, montmorillonite (e.g., sodium
montmorillonite, magnesium montmorillonite, and calcium
montmorillonite), beidellite, pyrophyllite, talc, vermiculite,
sobockite, stevensite, svinfordite, sauconite, saponite,
volkonskoite, hectorite, nontronite, kaolinite, dickite, nacrite,
halloysite, hisingerite, rectorite, tarosovite, ledikite, amesite,
baileychlore, chamosite, clinochlore, kaemmererite, cookeite,
corundophilite, daphnite, delessite, gonyerite, nimite, odinite,
orthochamosite, penninite, pannantite, rhipidolite, prochlore,
sudoite, thuringite, kanemite, makatite, ilerite, octosilicate,
magadiite, and kenyaite. In certain embodiments, the exfoliated
clay is an exfoliated smectite. In certain embodiments, the
exfoliated clay is exfoliated montmorillonite.
[0185] An exfoliated clay can be characterized by, for example, the
size of platelets and the aspect ratio of platelets. In certain
embodiments, the size of the platelets is about 1 .ANG. to about 50
.ANG., about 30 .ANG. to about 50 .ANG., or about 5 .ANG. to about
20 .ANG.. In certain embodiments, aspect ratio of the platelets is
about 100 to about 10,000, about 100 to about 5,000, or about 200
to about 2,000. In certain other embodiments, the exfoliated clay
has a mean particle size of less than about 500 nm, less than 100
nm, or less than 25 nm. In certain other embodiments, the
exfoliated clay has a mean particle size of from about 60 nm to
about 400 nm, about 50 nm to about 300 nm, about 40 nm to about 200
nm, or about 20 nm to about 150 nm.
[0186] In certain other embodiments, a partially exfoliated clay is
formed by exposing a clay to an effective amount of plant protein
composition (e.g., an isolated polypeptide composition) to form a
mixture and subjecting the mixture to exfoliation conditions, such
as high shear mixing and/or sonication. In certain other
embodiments, an exfoliated clay is formed by exposing a clay to an
effective amount of plant protein composition (e.g., an isolated
polypeptide composition) to form a mixture and subjecting the
mixture to exfoliation conditions, such as high shear mixing and/or
sonication.
Cellulose Nanoparticles
[0187] Cellulose nanoparticles can be added to the adhesive
composition to achieve certain performance properties, such as to
provide an adhesive with increased toughness and/or bond strength.
Cellulose nanoparticles can be obtained from commercial sources or
isolated from plant-based fibers by acid-hydrolysis. Cellulose
nanoparticles can be characterized by, for example, the size of the
nanoparticle, the cross-sectional shape of the nanoparticle, and/or
the cross-sectional length and aspect ratio of the nanoparticle.
Accordingly, in certain embodiments, the cellulose nanoparticle has
a size of from about 1 nm to about 2000 nm, about 10 nm to about
1000 nm, about 10 nm to about 500 nm, or about 10 nm to about 200
nm. In certain embodiments, the cross-sectional shape of the
nanoparticle may be triangular, square, pentagonal, hexagonal,
octagonal, circular, or oval. In certain other embodiments, the
average cross-sectional length of the cellulose nanoparticle is
about 0.1 nm to about 100 nm, or about 1 nm to about 10 nm.
[0188] One type of cellulose nanoparticles that may provide certain
advantages are cellulose nanofibers. Exemplary cellulose nanofibers
are described in, for example, U.S. Patent Application Publication
Nos. 2010/0233481, 2010/0240806, and 2010/0282422, each of which is
hereby incorporated by reference.
Catalyst
[0189] A catalyst may be added to the adhesive composition to
facilitate polymerization. Exemplary catalysts include, for
example, a primary amine, a secondary amine, a tertiary amine, an
organometallic compound, or a combination thereof. Exemplary
primary amines include, for example, methylamine, ethylamine,
propylamine, cyclohexylamine, and benzylamine. Exemplary secondary
amines include, for example, dimethylamine, diethylamine, and
diisopropylamine. Exemplary tertiary amines include, for example,
diazabicyclooctane (Dabco), triethylamine, dimethyl benzylamine,
bis-dimethylaminoethyl ether, tetramethyl guanidine,
bis-dimethylaminomethyl phenol, 2,2'-dimorpholinodiethyl ether,
2-(2-dimethylaminoethoxy)-ethanol,
2-dimethylaminoethyl-3-dimethylaminopropyl ether,
bis-(2-diaminoethyl)-ether, N,N-dimethyl piperazine,
N-(2-hydroxyethoxyethyl)-2-azanorbornane, Tacat DP-914 (Texaco
Chemical), Jeffcat.RTM., N,N,N,N-tetramethyl butane-1,3-diamine,
N,N,N,N-tetramethyl propane-1,3-diamine, N,N,N,N-tetramethyl
hexane-1,6-diamine, 2,2'-dimorpholinodiethyl ether (DMDEE), or a
mixture thereof. Exemplary organometallic compounds include, for
example, di-n-octyl tin mercaptide, dibutyl tin maleate, diacetate,
dilaurate, dichloride, bis-dodecyl mercaptide, tin(II)acetate,
ethyl hexoate and diethyl hexoate, Fe.sup.+3 2,4-pentanedionate
(FeAcAc), or lead phenyl ethyl dithiocarbamate.
[0190] In certain other embodiments, the catalyst is a transition
metal acetylacetonates, e.g., an acetylacetonate compound
comprising iron, copper, or nickel. In certain embodiments, the
transition metal acetylacetonate comprises a tertiary amine, e.g.,
2,2'-dimorpholino diethyl ether.
[0191] The amount of catalyst used in the adhesive composition can
be varied in order to optimize the features of the adhesive. In
certain embodiments, the catalyst is present in less than 1%
(wt/wt), 0.5% (wt/wt), or 0.1% (wt/wt) of the adhesive composition.
In certain other embodiments, the catalyst is present in a range
from 0.001% (wt/wt) to 0.75% (wt/wt), 0.001% (wt/wt) to 0.01%
(wt/wt), 0.01% (wt/wt) to 0.05% (wt/wt), or 0.05% (wt/wt) to 0.5%
(wt/wt) of the adhesive composition.
Tacking Agent
[0192] Exemplary tacking agents include, for example, glycerin,
corn syrup, soy oil, a poly(C.sub.2-C.sub.6)alkylene, mineral oil,
an ethylene/propylene/styrene copolymer, a
butylene/ethylene/styrene copolymer, or a mixture of one or more of
the foregoing. Other exemplary tacking agents are copolymers that
have a low glass transition temperature (Tg) (e.g., a latex-based,
acrylic copolymer with a Tg of less than about 0.degree. C., and
preferably less than about -20.degree. C.). In certain embodiments,
the additive is polybutene. In certain embodiments, the polybutene
has a weight average molecular weight of from about 200 g/mol to
about 20,000 g/mol, from about 200 g/mol to about 10,000 g/mol,
from about 200 g/mol to about 5,000 g/mol, from about 200 g/mol to
about 2,000 g/mol, from about 200 g/mol to about 1,000 g/mol, from
about 500 g/mol to about 2,000 g/mol, or from about 500 g/mol to
about 1,000 g/mol. Other tacking agents include a solid selected
from the group consisting of a terpene resin, a rosin ester
derivative, and a hydrocarbon-based derivative. When the tacking
agent is a solid, the tacking agent may optionally be pre-dissolved
in an oil-phase of the adhesive composition (e.g., in PMDI).
Alternatively, the solid tacking agent can be pre-melted and
dispersed in water by means of the protein component, or the solid
tacking agent can be ground and dispersed as fine particulates
directly into the adhesive composition.
Extender
[0193] Exemplary extenders include, for example, inert extenders or
active extenders. In certain embodiments, the inert extender is
vegetable particulate matter, limonene, vegetable oil, mineral oil,
dibasic esters, propylene carbonate, non-reactive modified aromatic
petroleum hydrocarbons, soy oil, castor oil, and in general any
non-active hydrogen containing liquid that can be incorporated into
an isocyanate based adhesive. Another inert extender is any
non-active hydrogen containing solid that is soluble, e.g., soluble
in oil or soluble in water. The active extender can be a
pyrrolidone monomer or polymers, an oxizolidone monomer or
polymers, an epoxidized oil, or an unsaturated oil, such as linseed
oil. Another active extender is a vinyl monomer or mixture of vinyl
monomers.
Surfactants & Adhesion Promoters
[0194] Exemplary surfactants include, for example, monomeric types,
polymeric types, or mixtures thereof. Exemplary adhesion promoters
include, for example, organosilanes and titanates.
Antimicrobial Agent
[0195] Antimicrobial agents known in the art that do not
substantially react with PMDI are contemplated for use in the
adhesive compositions and composites described herein. One
exemplary antimicrobial agent is polyalkylene glycol polymers, such
as polypropylene glycol.
Crosslinking Agent
[0196] In other embodiments, the additive can be a crosslinking
agent, for example, a crosslinking agent that can be used to bond
lignocellulosic material to glass. Exemplary crosslinking agents
include an organosilane, such as dimethyldichlorosilane (DMDCS),
alkyltrichlorosilane, methyltrichlorosilane (MTCS),
N-(2-aminoethyl)-3-aminopropyl trimethoxysilane (AAPS), or a
combination thereof. In other embodiments the polypeptide fractions
are combined with an organosilane to form an adhesive for bonding
one or more substrates together in any combination, said substrates
including glass, paper, wood, ceramic, steel, aluminum, copper,
brass, etc. The term "organosilane" refers to any group of
molecules including monomers, hydrolyzed monomers, hydrolyzed
dimers, oligomers, and condensation products of a trialkoxysilane
having a general formula:
(RO).sub.3Si--R'
where R is preferably a propyl, ethyl, methyl, isopropyl, butyl,
isobutyl, sec-butyl, t-butyl, or acetyl group, and R' is an
organofunctional group where the functionality may include an
aminopropyl group, an aminoethylaminopropyl group, an alkyl group,
a vinyl group, a phenyl group, a mercapto group, a styrylamino
group, a methacryloxypropyl group, a glycidoxy group, an isocyante
group, or others.
[0197] Similarly, a bis-trialkoxysilane having the general formula
(RO).sub.3Si--R'--Si(OR).sub.3 can also be employed as an
"organosilane" either alone or in combination with a
trialkoxysilane, where R is preferably a propyl, ethyl, methyl,
isopropyl, butyl, isobutyl, sec-butyl, t-butyl, or acetyl group,
and R' is a bridging organofunctional residue which may contain
functionality selected from the group consisting of amino groups,
alkyl groups, vinyl groups, phenyl groups, mercapto groups, and
others. Similarly, a tetraalkoxysilane having the general formula
(RO).sub.4Si can also be employed as an "organosilane" either alone
or in combination with a trialkoxysilane, or a bis-trialkoxysilane,
where R is preferably a propyl, ethyl, methyl, isopropyl, butyl,
isobutyl, sec-butyl, t-butyl, or acetyl group.
Agent that Improves Moisture-Resistance
[0198] Agents that improve moisture-resistance refer to those
materials that, when added to adhesive compositions described
herein, improve the ability of a wood composite formed from the
adhesive to be resistant to water, i.e., not absorb water.
Exemplary types of agents that improve moisture resistance include
fluorinated polyol compounds, silicones, siloxanes (including
functionalized siloxane polymers, such as hydroxy-terminated
siloxane polymers or hydroxyl alkyl siloxane polymers), polyolefin
polymers, wax (e.g., fatty acids (such as an alkyl carboxylic
acid), salts of a fatty acid (e.g., an alkali metal salt of an
alkyl carboxylic acid), esters of a fatty acid (e.g., an alkyl
ester of a carboxylic acid, an aryl ester of a carboxylic acid, an
alkyl ester of an alkanoic acid, or an aryl ester of an alkanoic
acid), fatty alcohols, mixtures of hydrophobic hydrocarbons,
water-based emulsions containing hydrophobic hydrocarbons dispersed
therein, a hydrocarbon wax, a fluoroalkylphosphate wax, a
fluorinated hydrocarbon wax, and a fluoroalkyl functionalized wax),
and hydrophobic oils. Another agent that improves
moisture-resistance is a fluorinated silicone. When an agent that
improves moisture-resistance is present in an adhesive composition,
it is desirably present in an amount effective to increase moisture
resistance (e.g., an increase in moisture resistance of at least
about 2%, 5%, 10%, or 20% compared to the moisture resistance of a
composite formed from an adhesive composition lacking the agent
that improves moisture-resistance).
[0199] Agents that improve moisture-resistance may be present in
the final composite at a weight percent in the range of about 0.01%
(w/w) to about 5% (w/w), about 0.01% (w/w) to about 2% (w/w), about
0.01% (w/w) to about 1% (w/w), about 0.01% (w/w) to about 0.5%,
about 0.1% (w/w) to about 2% (w/w), (w/w), about 0.1% (w/w) to
about 1% (w/w), (w/w), about or 0.5% (w/w) to about 1% (w/w).
[0200] One exemplary fluorinated polyol compound is FluoroLink D-10
fluorinated polyol that is commercially available from Solvay
Solexis, Inc. Exemplary silicones include Dow Corning FS-1265
Fluid, 300 cST (Trifluoropropyl Methicone) from Dow Corning), and
T-Sil-6011 SE Emulsion (60% Solids), from Siovation, Inc. which is
a emulsion containing 60% w/w silicones. The silicone may be
organically modified, such as C.sub.20-24 Alkyl Methicone,
C.sub.24-28 Alkyl Methicone, C.sub.30-45 Alkyl Methicone, Stearyl
Dimethicone, Biphenyl Dimethicone, Stearoxy Dimethicone,
C.sub.20-24 Alkyl Dimethicone, or C.sub.24-28 Alkyl
Dimethicone.
[0201] Exemplary types of functionalized siloxane polymers include
(1) a hydroxy-terminated siloxane polymer such as
hydroxy-terminated polydimethylsiloxane (e.g., T-Sil-80, a linear
hydroxy terminated polydimethylsiloxane from Siovation, Inc.), (2)
a hydroxyl alkyl polydimethylsiloxane (e.g., Tego Protect-5000
functionalized silicone fluid commercially available from Evonik
Tego Chemie GmbH), and (3) a fluorinated siloxane. Exemplary waxes
include Hexion EW-58H; BE Square 165 Amber Petroleum
Microcrystalline Wax commercially available from Baker Hughes,
Inc., which is a mixture comprising paraffinic, isoparaffinic, and
naphthenic hydrocarbons; Masurf FS 115 Emulsion (a
fluoroalkylphosphate wax dispersion in water--28% Solids)
commercially available from Mason Chemical Company; carnauba wax;
candelilla wax; japan wax; beeswax; rice bran wax; montan wax;
paraffin; ceresin; lanolin; ozokerita; slack wax (which is
semi-refined wax having an oil content up to about 30 mass percent,
and often produced by chilling and solvent filter-pressing wax
distillate); polyethylene wax; a fatty acid or salt thereof (e.g.,
C.sub.10-25 alkanoic acid, a salt of a C.sub.10-25 alkanoic acid, a
C.sub.10-25 alkenoic acid, a salt of an C.sub.10-25 alkenoic acid;
such as stearic acid, zinc stearate, or lauric acid), a fatty ester
(e.g., an ester of an C.sub.10-25 alkanoic acid or C.sub.10-25
alkenoic acid); or fatty alcohol (e.g., C.sub.10-25 hydroxy alkane
or C.sub.10-25 hydroxy alkene).
[0202] Exemplary hydrophobic polymers include a polyolefin (e.g.,
polyethylene, polypropylene, polybutylene, polystyrene, copolymers
of the foregoing, polyethylene/polyvinyl acetate copolymer, and
polyethylene/polyacrylic acid copolymer).
[0203] Exemplary hydrophobic oils include soy lecithin, caster oil,
and a fluorinated hydrocarbon liquid.
[0204] Another agent that improves moisture resistance is a mixture
of a silicone and a terpene compound. An exemplary silicone is Tego
Protect-5000 functionalized silicone fluid sold by Evonik Tego
Chemie GmbH. Exemplary terpene compounds contemplated for use
include terpene compounds that are a solid at room temperature, a
liquid at room temperature, and/or have a molecular weight of less
than about 2000 g/mol, about 1000 g/mol, about 500 g/mol, or about
200 g/mol. In certain embodiments, the terpene compound is
limonene. In certain embodiments, the agent that improves moisture
resistance is a mixture of Tego Protect-5000 functionalized
silicone fluid and limonene. In certain other embodiments, the
agent that improves moisture resistance is a silicone and limonene.
It is understood that an agent that improves moistures resistance
(e.g., a silicone and limonene) can be used in combination with
other additives, such as montmorillonite that has been at least
partially exfoliated.
[0205] In certain embodiments, the agent that improves
moisture-resistance is a polymer agent that improves
moisture-resistance, a wax agent that improves moisture-resistance,
or a mixture thereof. In certain other embodiments, the agent that
improves moisture-resistance is a silicone, a siloxane, a
fluorinated polyol, a fluoroalkyl phosphate ester, a fluoroalkyl
carboxylic ester, a salt of a fluoroalkanoic acid, a wax that
improves moisture-resistance, or a mixture thereof. In certain
other embodiments, the agent that improves moisture-resistance is a
wax that improves moisture-resistance, such as a mixture of
hydrophobic hydrocarbons, water-based emulsions containing
hydrophobic hydrocarbons dispersed therein, a fluoroalkylphosphate
wax, a fluorinated hydrocarbon wax, or a fluoroalkyl functionalized
wax. In certain other embodiments, the agent that improves
moisture-resistance is a silicone, a siloxane, a fluorinated
polyol, a fluoroalkyl phosphate ester, or a fluoroalkyl carboxylic
ester. In certain other embodiments, the agent that improves
moisture-resistance is a silicone, a siloxane, a fluorinated
polyol, a fluoroalkyl phosphate ester, a fluoroalkyl carboxylic
ester, a salt of a fluoroalkanoic acid, or a mixture thereof. In
certain other embodiments, the agent that improves
moisture-resistance is a silicone, a siloxane, a fluorinated
polyol, a fluoroalkyl phosphate ester, a fluoroalkyl carboxylic
ester, or a wax that improves moisture-resistance. In certain other
embodiments, the agent that improves moisture-resistance is a
fluorinated polyol, a silicone, a siloxane, or wax that improves
moisture-resistance. In yet other embodiments, the agent that
improves moisture-resistance is a mixture comprising hydrophobic
hydrocarbons.
[0206] The term "fluoroalkyl phosphate ester" as used herein refers
to a compound comprising a phosphate group bonded to at least one
fluoroalkyl group, such as represented by
P(O)(OR.sup.1)(OR.sup.2).sub.2, wherein R.sup.1 is a fluoroalkyl
group, and R.sup.2 represents independently for each occurrence
hydrogen, alkyl, fluoroalkyl, aryl, aralkyl, heteroalkyl,
heteroaryl, heteroaralkyl, an alkali metal, ammonium, or a
quaternary amine, or two occurrences of R.sup.2 are taken together
to form an alkaline earth metal.
pH Modulator
[0207] The pH modulator can be an acid or base. In certain
embodiments, the pH modulator is an alkali metal hydroxide (e.g.,
sodium hydroxide or calcium hydroxide) or an alkali metal salt of a
carboxylate organic compound (e.g., an alkali metal salt of
citrate, such as di-sodium citrate).
Composite-Release Promoter
[0208] The composite-release promoter acts to facilitate release of
the wood composite from the press apparatus used to make the
composite. In the absence of a composite-release promoter, certain
composites may stick to the press apparatus, making it difficult to
separate the composite from the press apparatus. The
composite-release promoter solves this problem by facilitating
release of the wood composite. Exemplary composite-release
promoters include silicones (e.g., silicones described above),
fatty acids, a salt of a fatty acid, waxes, and amide compounds.
Exemplary fatty acids or salts thereof include a C.sub.10-25
alkanoic acid, a salt of a C.sub.10-25 alkanoic acid, a C.sub.10-25
alkenoic acid, a salt of an C.sub.10-25 alkenoic acid; e.g.,
stearic acid, zinc stearate, lauric acid, oleic acid or a salt
thereof (such as an alkali metal salt of oleic acid, such as
potassium oleate). It is understood that a mixture of two or more
of the aforementioned exemplary composite-release promoters can
also be used in the adhesive compositions herein. An exemplary
amide compound is N,N'-ethylenebisstearamide. Exemplary waxes
include those described above for the agent that improves moisture
resistance, and in particular, Hexion EW-58H; E Square 165 Amber
Petroleum Microcrystalline Wax commercially available from Baker
Hughes, Inc.; and Masurf FS 115 Emulsion (28% Solids) commercially
available from Mason Chemical Company. One additional advantage of
the protein component in the adhesive composition is that it can
facilitate dispersion of the composite-release promoter--this
feature allows less composite-release promoter to be used in the
adhesive composition and final composite product. Reducing the
amount of composite-release promoter is advantageous for agents
that are relatively more expensive, such as certain silicone
composite-release promoters.
[0209] In certain embodiments, the composite-release promoter is a
silicone.
[0210] Further, in certain embodiments, a composite-release
promoter is present in the final composite at a weight percent in
the range of about 0.01% (w/w) to about 5% (w/w), about 0.01% (w/w)
to about 2% (w/w), or about 0.01% (w/w) to about 1% (w/w).
Formaldehyde Scavenging Agent
[0211] A variety of formaldehyde scavenging agents are described in
the literature and are contemplated to be amenable to the present
invention. Different formaldehyde scavenging agents have different
reactivity profiles, and a particular formaldehyde scavenging agent
(e.g., H.sub.2NC(O)NH.sub.2, Me.sub.2NC(O)NH.sub.2, or
CH.sub.3CH.sub.2NH.sub.2) can be selected to optimize the
performance properties of the adhesive composition and/or binder
composition formed by the adhesive. Accordingly, in certain
embodiments, the formaldehyde scavenging agent has the formula
RNH.sub.2, R.sub.2NH, RC(O)NH.sub.2, RN(H)C(O)NH.sub.2,
R.sub.2NC(O)NH.sub.2, or RN(H)C(O)N(H)R, wherein R represents
independently for each occurrence H, alkyl, aryl, or aralkyl. In
certain embodiments, the formaldehyde scavenging agent has the
formula RN(H)C(O)N(H)R, wherein R represents independently for each
occurrence H, alkyl, aryl, or aralkyl. In certain other
embodiments, the formaldehyde scavenging agent is
H.sub.2NC(O)NH.sub.2, H.sub.2NC(O)N(H)Me, MeN(H)C(O)N(H)Me,
H.sub.2NC(O)N(CH.sub.3).sub.2, CH.sub.3C(O)NH.sub.2,
CH.sub.3CH.sub.2C(O)NH.sub.2, CH.sub.3NH.sub.2,
CH.sub.3CH.sub.2NH.sub.2, (CH.sub.3).sub.2NH, or
(CH.sub.3CH.sub.2).sub.2NH. In still other embodiments, the
formaldehyde scavenging agent is H.sub.2NC(O)NH.sub.2.
[0212] The term "alkyl" as used herein refers to a saturated
straight or branched hydrocarbon, such as a straight or branched
group of 1-12, 1-10, or 1-6 carbon atoms, referred to herein as
C.sub.1-C.sub.12alkyl, C.sub.1-C.sub.10alkyl, and
C.sub.1-C.sub.6alkyl, respectively. Exemplary alkyl groups include,
but are not limited to, methyl, ethyl, propyl, isopropyl,
2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl,
3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl,
2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl,
2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl,
2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl,
isobutyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl,
octyl, etc.
[0213] The term "aryl" as used herein refers to refers to a mono-,
bi-, or other multi-carbocyclic, aromatic ring system. Unless
specified otherwise, the aromatic ring is optionally substituted at
one or more ring positions with substituents selected from
alkanoyl, alkoxy, alkyl, alkenyl, alkynyl, amido, amidino, amino,
aryl, arylalkyl, azido, carbamate, carbonate, carboxy, cyano,
cycloalkyl, ester, ether, formyl, halogen, haloalkyl, heteroaryl,
heterocyclyl, hydroxyl, imino, ketone, nitro, phosphate,
phosphonato, phosphinato, sulfate, sulfide, sulfonamido, sulfonyl
and thiocarbonyl. The term "aryl" also includes polycyclic ring
systems having two or more cyclic rings in which two or more
carbons are common to two adjoining rings (the rings are "fused
rings") wherein at least one of the rings is aromatic, e.g., the
other cyclic rings may be cycloalkyls, cycloalkenyls,
cycloalkynyls, and/or aryls. Exemplary aryl groups include, but are
not limited to, phenyl, tolyl, anthracenyl, fluorenyl, indenyl,
azulenyl, and naphthyl, as well as benzo-fused carbocyclic moieties
such as 5,6,7,8-tetrahydronaphthyl. In certain embodiments, the
aryl group is not substituted, i.e., it is unsubstituted.
[0214] The term "aralkyl" as used herein refers to an aryl group
having at least one alkyl substituent, e.g. aryl-alkyl-. Exemplary
aralkyl groups include, but are not limited to, arylalkyls having a
monocyclic aromatic ring system, wherein the ring comprises 6
carbon atoms. For example, "phenylalkyl" includes
phenylC.sub.4alkyl, benzyl, 1-phenylethyl, 2-phenylethyl, etc.
[0215] The amount of formaldehyde scavenging agent in the adhesive
formulation can adjusted to optimize the performance properties of
the adhesive composition and/or binder composition formed by the
adhesive. In certain embodiments, the mole ratio of formaldehyde
scavenging agent to reactive prepolymer is at least about 0.1:1, at
least about 0.5:1, at least about 1:1, at least about 2:1, at least
about 3:1, at least about 4:1 or at least about 5:1. In certain
embodiments, the mole ratio of formaldehyde scavenging agent to
reactive prepolymer is in the range of from about 0.01: to about
0.5:1, from about 0.5:1 to about 5:1, or from about 1:1 to about
4:1. In still other embodiments, the mole ratio of formaldehyde
scavenging agent to reactive prepolymer is at least 0.05:1. In
still other embodiments, the mole ratio of formaldehyde scavenging
agent to reactive prepolymer is at least 5:1.
[0216] In certain embodiments, the formaldehyde scavenging agent is
present in an amount from about 1% to about 50% (w/w), from about
1% to about 30% (w/w), from about 1% to about 20% (w/w), from about
5% to about 50% (w/w), from about 5% to about 30% (w/w), from about
5% to about 20% (w/w), from about 10% to about 50% (w/w), from
about 10% to about 30% (w/w), or from about 10% to about 20% (w/w)
of the adhesive composition. In certain other embodiments, the
formaldehyde scavenging agent is present in an amount from about 1%
to about 50% (w/w) of the adhesive composition. In still other
embodiments, the formaldehyde scavenging agent is present in an
amount from about 2% to about 30% (w/w) of the adhesive
composition.
Additional Polymer Additives
[0217] In certain embodiments, the adhesive composition further
comprises either an ethylene copolymer resin, a hydroxyl
functionalized polymer, or mixtures thereof. Non-limiting examples
of suitable ethylene copolymer resins include ethylene vinyl
acetate (EVA), ethylene-co-vinylacetate-co-acrylic acid,
ethylene-co-vinylacetate-co-methacrylic acid,
ethylene-co-vinylacetate-co-vinylalcohol, carboxylated vinyl
acetate-ethylene copolymers, and ethylene vinyl alcohol (EVOH)
resins. Non-limiting examples of hydroxyl functionalized polymers
include water soluble or partially water soluble polymers such as
polyvinylalcohol, polyvinylbutyral-co-vinylalcohol,
polyvinylacetate-co-vinylalcohol and the like; and carbohydrates
such as carboxymethylcellulose, ethylmethylcellulose, etc.
[0218] The ethylene copolymer can be used as a water dispersion
agent (i.e., an EVA latex). The dispersion agent can be a polymer
latex containing a carboxylated vinyl acetate-ethylene terpolymer
stabilized with poly-(vinyl alcohol), commercially known as AIRFLEX
426.RTM. from Air Products, Inc. (63% solids by weight). In certain
other embodiments, the dispersion agent is Wacker VINNAPAS.RTM.
426, which is a carboxylated, high solids vinyl acetate-ethylene
(VAE) copolymer dispersion with a glass transition temperature (Tg)
of 0.degree. C., sold by Wacker Chemie, AG. The ethylene copolymer
can be used at a level of from 5% to 50% by weight, from 10% to 40%
by weight, or from 15% or 30% by weight of the total isocyanate
reactive component (the level of ethylene copolymer is expressed on
a solids basis, and does not include the level of water in the
latex). Additional latex polymers that may be used include, for
example, acrylic homopolymers (e.g., poly(methylmethacrylate) and
poly(isobutylmethacrylate)) and acrylic copolymers (e.g.,
poly(isobutylmethacrylate-co-methylacrylate) and
poly(ethylene-co-methylmethacrylate)).
Fire Retardants
[0219] Exemplary fire retardants include, for example, (i)
phosphoric acid or a salt thereof, such as a mono-ammonium
phosphate, di-ammonium phosphate, ammonium poly-phosphate, melamine
phosphate, guanidine phosphate, urea phosphate, alkali metal
phosphate, and alkaline earth metal phosphate, (ii) a halogenated
phosphate compound, (iii) a phosphate ester, such as tri-o-cresyl
phosphate and tris(2,3-dibromopropyl)phosphate, (iv) a chlorinated
organic compound, such as a chlorinated hydrocarbon or chlorinated
paraffin, (iv) a brominated organic compound, such as a brominated
hydrocarbon, bromo-bisphenol A, tetrabromobisphenol A (TBBPA),
decabromobiphenyl ether, octabromobiphenyl ether,
tetrabromobiphenyl ether, hexabromocyclododecane,
bis(tetrabromophthalimido) ethane, tribromophenol, and
bis(tribromophenoxy)ethane, (v) a brominated oligomer or brominated
polymer, such as TBBPA polycarbonate oligomer, brominated
polystyrene, and TBBPA epoxy oligomer, (vi) a borate compound, such
as an alkali metal borate, ammonium borate, or mixture comprising
one or more of borax, boric acid, boric oxide, and disodium
octoborate, (vii) aluminium materials, such as aluminium trihydrate
and aluminium hydroxide, (viii) an alkaline earth metal hydroxide,
such as magnesium hydroxide, (ix) an alkali metal bicarbonate, such
as sodium bicarbonate, (x) an alkaline earth metal carbonate, such
as calcium carbonate, (xi) antimony trioxide, (xii) hydrated
silica, (xiii) hydrated alumina, (xiv) dicyandiamide, (xv) ammonium
sulfate, and (xvi) a mixture of guanylurea phosphate and boric
acid, such as those described in International Patent Application
Publication No. WO 02/070215, which is hereby incorporated by
reference, (xvii) graphite, (xviii) melamine, and (xix) a
phosphonate compound, such as
diethyl-N,N-bis(2-hydroxyethyl)aminoethyl phosphonate;
dimethyl-N,N-bis(2-hydroxyethyl)aminomethyl phosphonate;
dipropyl-N,N-bis(3-hydroxypropyl)aminoethyl phosphonate; and
dimethyl-N,N-bis(4-hydroxybutyl)aminomethyl phosphonate, such as
described in U.S. Pat. No. 6,713,168, which is hereby incorporated
by reference.
[0220] In certain embodiments, the fire retardant is (i) phosphoric
acid or a salt thereof, such as a mono-ammonium phosphate,
di-ammonium phosphate, ammonium poly-phosphate, melamine phosphate,
guanidine phosphate, urea phosphate, alkali metal phosphate, and
alkaline earth metal phosphate, (ii) a phosphate ester, such as
tri-o-cresyl phosphate and tris(2,3-dibromopropyl) phosphate,
aluminium trihydrate and aluminium hydroxide, (iii) an alkaline
earth metal hydroxide, such as magnesium hydroxide, (iv) an alkali
metal bicarbonate, such as sodium bicarbonate, (v) antimony
trioxide, or (vi) hydrated alumina. In certain other embodiments,
the fire retardant is colemanite
(CaB.sub.3O.sub.4(OH).sub.3--H.sub.2O).
Wood Preservatives
[0221] Exemplary wood preservatives include, for example, (i)
chromated copper arsenate (CCA), (ii) alkaline copper quaternary,
(iii) copper azole, (iv) a borate preservative compound, (v) a
sodium silicate-based preservative compound, (vi) a potassium
silicate-based preservative compound, (vii) a bifenthrin
preservative compound, (viii) a coal-tar creosote, (ix) linseed
oil, (x) tung oil, and (xi) an insecticide, such as an
organochloride compound, organophosphate compound, carbamate
compound, pyrethroid, neonicotinoid, and ryanoid.
IX. General Considerations for Adhesive Compositions
[0222] The adhesive composition may be in the form of a liquid or
powder. Liquid form adhesives may provide advantages for certain
applications, such as where it is desirable to distribute a thin
film of adhesive over a large surface area. Dry blend adhesives may
provide advantages for certain applications, such as those where it
is desirable to minimize the amount of volatile compounds (e.g.,
water) in the adhesive composition. Factors that can affect the
viscosity, moisture resistance, bond strength, and other properties
of the adhesive composition are described below.
Dry Blend Adhesive Compositions
[0223] The adhesive composition may be in the form of a dry blend.
A first type of dry blend adhesive composition may be formed by
mixing ground plant meal with one or more liquid or solid
additives. The liquid or solid additives are typically added in an
amount less than about 10% w/w of the plant meal. Alternatively,
the liquid or solid additives are may be blended with the plant
meal during grinding to form the ground plant meal. The ground
plant meal containing one or more additives is desirably a dry and
flowable material. Exemplary additives are described above in
Section VIII, and include intercalated clays, partially exfoliated
clays, exfoliated clays, mixture of a silicone and a terpene
compound (e.g., limonene), mineral oil, soy oil, castor oil, soy
methyl ester, canola methyl ester urea, glycerin, propylene glycol,
propylene carbonate, polyols, crosslinkers like PMDI, lignin,
epoxies such as glycidyl end-capped
poly(bisphenol-A-co-epichlorohydrin) (BPA) and trimethylolpropane
triglycidyl ether, polymer latexes, and catalysts. In certain other
embodiments, a phenol-formaldehyde resin or urea-formaldehyde resin
may be added to the plant meal or ground plant meal. In yet other
embodiments, lignin may be added to the plant meal or ground plant
meal.
[0224] A second type of dry blend adhesive composition may be
formed by mixing ground plant meal with a dry powder ingredient,
such as an additive that is not a liquid (e.g., a clay (such as an
intercalated clay, a partially exfoliated clay, or an exfoliated
clay), silicone, lignin, or mixture of a hydroxyaromatic compound
and an aldehyde compound, such as a phenol-formaldehyde resin).
[0225] A third type of dry blend adhesive may be formed by mixing
the first type of adhesive (as described above) with any other dry
or liquid ingredient that may impart beneficial properties to the
adhesive composition.
[0226] The dry adhesives described above may be used as binders in
the manufacture of wood composites. Such wood composites may be
prepared by first mixing wood particulates with the dry blend
adhesive composition to form a mixture, and then subjecting the
mixture to elevated temperature and pressure to facilitate
densification and curing of the adhesive. The amount of cured
adhesive in the wood composite may be, for example, from about 0.2%
and 20% w/w of the cured wood composite.
Amount of Plant Protein Composition
[0227] The amount of plant protein composition in the adhesive
composition can be adjusted to achieve particular performance
properties. For example, in certain embodiments, the adhesive
composition comprises no less than about 2%, 5%, 10%, 15%, 20%,
25%, or 30% by weight of the plant protein composition (i.e.,
ground plant meal or isolated polypeptide composition) described
herein (based on the dry weight of the protein component). The
maximum loading of the protein component can be based on, for
example, optimizing stability and viscosity. In certain
embodiments, the total concentration of plant protein composition
may be of up to 35% (wt/wt). Higher viscosity compositions formed
from higher weight percentages of the plant protein composition
described herein can be beneficial in applications where it is
desirable for the uncured adhesive to exhibit cold-tack, flow
resistance, sag resistance, and gap-filling characteristics.
Viscosity Considerations
[0228] The viscosity of the adhesive can be designed with a
particular application in mind. In one embodiment, where gap
filling adhesives are required, the minimum viscosity of the
adhesive (e.g., polyisocyanate-containing adhesive) should be no
less than (NLT) 2000 cps, 3000 cps, or NLT 4000 cps, as measured at
25.degree. C. The viscosity of the adhesive composition (e.g., a
polyisocyanate-containing adhesive) can be optimized by adjusting
the amount of protein component (i.e., ground plant meal or
isolated polypeptide composition) described herein and/or the
conditions used for preparing the composition. Typical conditions
are in the range from 25 to 100.degree. C. at ambient pressure,
with agitation of the mixture until a sufficiently homogeneous
composition is achieved. In addition, the viscosity of the adhesive
composition can be optimized by adjusting the amount of water in
the adhesive. For example, in certain embodiments, the adhesive
composition contains water in an amount that is less than about 70%
w/w, 60% w/w, 50% w/w, 40% w/w, 30% w/w, 20% w/w, or 10% w/w of the
adhesive composition. In certain other embodiments, the adhesive
composition contains water in an amount ranging from about 10% w/w
to about 40% w/w, 20% w/w to about 50% w/w, about 30% w/w to about
60% w/w, about 40% w/w to about 70% w/w, about 50% w/w to about 80%
w/w, or about 50% w/w to about 60% w/w of the adhesive
composition.
[0229] In order to optimize the viscosity of the adhesive
composition, the adhesive composition may contain ground plant meal
in an amount such that the viscosity of the adhesive formulation
increases by no more than about 25% within about 20 minutes, or no
more than about 50% within about 20 minutes, after mixing the
prepolymer and ground plant meal with a nucleophile. In certain
other embodiments, the ground plant meal is present in an amount
such that the viscosity of the adhesive formulation increases by no
more than about 40% within about 30 minutes (or no more than about
40% with about 100 minutes) after mixing the prepolymer and ground
plant meal with a nucleophile. In certain other embodiments, the
ground plant meal is present in an amount such that the viscosity
of the adhesive formulation remains less than about 1100 cps within
about 150 minutes after mixing, less than about 1100 cps within
about 200 minutes after mixing, less than about 1500 cps within
about 150 minutes after mixing, less than about 1500 cps within
about 225 minutes after mixing, less than about 50,000 cps within
about 150 minutes after mixing, less than about 50,000 cps within
about 20 minutes after mixing, less than about 30,000 cps within
about 20 minutes after mixing, less than about 300,000 cps within
about 60 minutes after mixing, or less than about 100,000 cps
within about 60 minutes after mixing the prepolymer and ground
plant meal with a nucleophile.
[0230] In certain embodiments, the viscosity of the adhesive
composition is no more than (NMT) 500,000 cps, NMT 300,000 cps, NMT
200,000 cps, or NMT 100,000 cps, NMR 50,000 cps, NMT 25,000 cps,
NMT 10,000 cps, or NMT 5,000 cps as measured at 25.degree. C. until
the adhesive composition is cured. In certain other embodiments,
the viscosity of all the types of polyisocyanate compositions as
described herein, is no more than (NMT) 500,000 cps, NMT 300,000
cps, NMT 200,000 cps, or NMT 100,000 cps, NMR 50,000 cps, NMT
25,000 cps, NMT 10,000 cps, or NMT 5,000 cps as measured at
25.degree. C. until the polyisocyanate composition is cured.
[0231] Certain of the adhesives described herein are liquids having
viscosities low enough to render them pourable, sprayable, or
curtain-coatable. For pourable or sprayable adhesive compositions,
the viscosity of the adhesive composition is desirably no more than
(NMT) 500 cps, NMT 1000 cps, NMT 2000 cps, or NMT 5000 cps, as
measured at 25.degree. C. The viscosity of the adhesive composition
can be optimized by adjusting the amount of protein component
(i.e., ground plant meal or isolated polypeptide composition)
described herein and/or the conditions used for preparing the
composition. Alternatively, certain of the adhesives described
herein are non-pourable, extrudable, spreadable gels or pastes.
Non-pourable, extrudable, spreadable gels, or pastes may become
pourable, sprayable, or curtain-coatable liquids at elevated
temperature, and may optionally revert to non-pourable, extrudable
or spreadable gels or pastes upon cooling.
[0232] The adhesive composition can be also characterized according
to the weight percent of the ground plant meal in the composition.
In certain embodiments, the ground plant meal is present in an
amount from about 1% to about 90% (w/w), from about 1% to about 70%
(w/w), from about 1% to about 50% (w/w), from about 1% to about 30%
(w/w), from about 10% to about 90% (w/w), from about 10% to about
70% (w/w), from about 10% to about 50% (w/w), from about 10% to
about 30% (w/w), from about 20% to about 90% (w/w), from about 20%
to about 70% (w/w), from about 20% to about 50% (w/w), or from
about 20% to about 30% (w/w) of the adhesive composition. In
certain other embodiments, the ground plant meal is present in an
amount from about 5% to about 35% (w/w), or from about 5% to about
50% (w/w), of the adhesive composition. In still other embodiments,
the ground plant meal is present in an amount from about 15% to
about 25% (w/w) of the adhesive composition.
[0233] In certain other embodiments, the polypeptide containing
adhesives described herein are liquids, gels, or pastes stable
enough to be stored for at least one week, at least two weeks, at
least one month, or at least three months at ambient temperature
(25.degree. C.), and protected from moisture. The term "stable" in
connection with the viscosity of the polyisocyanate composition
refers to a viscosity that does not increase by more than 10%, 25%,
or 30%, from its initial value.
[0234] In addition, the isolated polypeptide composition and the
adhesive composition can be designed to have a polydispersity
index. The term "polydispersity index" refers to the ratio between
the weight average molecular weight and the number average
molecular weight (i.e., PDI=Mw/Mn).
[0235] The terms "number average molecular weight," denoted by the
symbol Mn and "weight average molecular weight," denoted by the
symbol Mw, are used in accordance with their conventional
definitions as can be found in the open literature. The weight
average molecular weight and number average molecular weight can be
determined using analytical procedures described in the art, e.g.,
chromatography techniques, sedimentation techniques, light
scattering techniques, solution viscosity techniques, functional
group analysis techniques, and mass spectroscopy techniques (e.g.,
MALDI mass spectroscopy). For instance, as illustrated in Example
2, average molecular weight and number average molecular weight of
the polypeptide composition was determined by MALDI mass
spectroscopy.
[0236] Further, it is contemplated that isolated polypeptide
compositions having different molecular weights may provide
adhesive compositions having different properties. As such, the
weight average molecular weight, number average molecular weight,
and polydispersity index can be an important indicator when
optimizing the features of the adhesive composition. In particular,
it is contemplated that the ability to optimize the molecular
weight characteristics of the isolated polypeptide compositions
provides advantages when preparing an adhesive composition for a
particular use. Further advantages include obtaining adhesive
compositions with similar properties even though the isolated
polypeptide composition may be obtained from a different source
(e.g., soy vs. castor) or when similar protein sources are
harvested during different seasons, over varying periods of time,
or from different parts of the world. For example, proteins
isolated from soy and castor (each having different molecular
weight distributions) can be made to have similar molecular weight
distributions through digestion and fractionation processes
described herein (see Example 2). Accordingly, the ability to
measure and control the consistency of molecular weight
distributions is contemplated to be beneficial when optimizing
various features of the adhesive composition, e.g., long-term
reproducibility of physical properties and process characteristics
of formulated adhesives. The molecular weight characteristics of
the ground plant meal or isolated polypeptide composition can be
altered by subjecting the proteins therein to enzymatic digestion
or fractionation according to the procedures described herein.
[0237] In certain embodiments, the PDI of the adhesives provided
herein is from about 1 to about 3, from 1 to 1.5, from 1.5 to 2,
from 2 to 2.5, from 2.5 to 3, from 1 to 2, from 1.5 to 2.5, or from
2 to 3.
Tack Strength/Bond Strength
[0238] The tack or bond strength of the pressure sensitive
adhesives (PSA) can be controlled through a number of means, such
as shifting the glass transition (T.sub.g) to higher or lower
temperatures (by controlling the levels of monomeric and/or
polymeric plasticizers) or incorporating flatting agents such as
silicas, glass spheres, clays, and the like; by adjusting the
crosslink density to higher or lower levels; by increasing or
decreasing the plasticizer concentration; by blending with higher
or lower molecular weight polymers; or by employing some
combination of these techniques.
[0239] It is understood that when evaluating the tack or bond
strength of a composite formed using an adhesive, the maximum
achievable strength of the composite is dictated by the cohesive
strength of the wood itself. To illustrate, if the adhesive is
cohesively stronger than the wood, then wood failure will be the
outcome. Further, it is contemplated that the adhesive composition
may be tailored to provide a bond strength appropriate for
particular applications by selecting particular polypeptide
fractions, prepolymers, catalysts, and/or other additives.
[0240] Depending upon the application, the resulting adhesives may
comprise from about 20% to about 80%, from about 30% to about 70%,
from about 40% to about 60% (w/w) of prepolymer in the total
adhesive (binder) composition.
[0241] Furthermore, depending upon the application, the resulting
cured article can comprise from about 0.05% to about 10%, from
about 0.05% to about 5.0%, from about 0.1% to about 4.0%, from
about 0.2% to about 3.0%, or from about 0.3% to about 2.0% (w/w) of
prepolymer. In certain embodiments, the cured article can comprise
from about 0.05% to about 2.5% (w/w) of prepolymer. In other
embodiments, the cured article can comprise from about 2.5% to
about 4% (w/w) of prepolymer.
[0242] Furthermore, an article fabricated from one or more of the
adhesives described herein can contain from about 1% to about 15%,
or from about 2% to about 10%, or from about 3% to about 8%, or
from about 4% to about 7%, or from about 3% to about 6% (w/w) of
binder (adhesive) per cured article. In certain embodiments, the
article fabricated from the adhesive may contain greater than 5%
(w/w) of binder per cured article. In certain other embodiments,
the article comprises from about 1.5% to about 2.5% of binder per
cured article.
[0243] Composite materials can contain from about 5% to about 85%
(w/w), about 15% to about 75% (w/w), about 30% to about 65% (w/w),
about 1% to about 10%, about 10% to about 20%, or about 20% to
about 70% (w/w) binder. Laminate materials can contain from about
0.1% to about 10% (w/w), about 0.5% to about 5%, about 1% to about
3% (w/w), about 1% to about 10%, about 20% to about 30%, or about
30% to about 70% (w/w) binder.
[0244] In certain embodiments, the adhesives described herein can
be used in the manufacture of particle board, medium density
fiberboard (MDF), high density fiberboard (HDF), or oriented strand
board (OSB). With regard to the preparation of moisture-resistant
cured particle board composites, the composites can comprise a
total binder level ranging from about 1.5% to about 11% (w/w), or
from about 2.5% to about 4.5% (w/w), of the cured composite,
wherein the binder includes a protein component (i.e., ground plant
meal or isolated polypeptide composition) and a PMDI fraction with
an optional catalyst. The amount of PMDI can range from about 5% to
about 30%, or from about 30% to about 70%, by weight of the cured
binder. The PMDI fraction can comprise from about 0.8% to about 10%
(w/w), from about 0.8% to about 4% (w/w), or from about 1.3% to
about 2.3% (w/w), of the cured composite. In certain embodiments,
the PMDI component can be replaced with a phenol-formaldehyde
resin, lignin, or some combination thereof. In other embodiments,
PMDI can be used in combination with a phenol-formladehyde resin,
lignin, or both.
[0245] In another embodiment, a moisture resistant composites can
be prepared with a total binder level ranging from about 1.5% to
about 11% (w/w), or from about 1.5% to about 2.5% (w/w), of the
cured composite, wherein the binder includes a protein component
(i.e., ground plant meal or isolated polypeptide composition) and a
PMDI fraction with an optional catalyst. The PMDI fraction can
comprise from about 0.1% to about 10% (w/w), from about 0.1% to
about 5% (w/w), from about 0.2% to about 2.5% (w/w), or from about
0.3% to about 1.4% (w/w) of the cured composite.
Moisture-Resistant Adhesive Compositions
[0246] In another embodiment, a moisture-resistant cured particle
board composite can be prepared containing a total binder level
ranging from about 1.5% to about 15%, from about 1.5% to about 11%,
or from about 2.5% to about 3.1%, by weight of the cured composite,
wherein the binder comprises a protein component (i.e., ground
plant meal or isolated polypeptide composition), an optional
polymer latex fraction, and a PMDI fraction with optional catalyst.
The PMDI comprises from about 5% to about 65% by weight of the
cured binder and from about 0.1% to 10%, from about 0.1% to about
5%, from about 0.2% to about 2.5%, or from about 0.3% to about 2%
by weight of the cured composite. The optional polymer latex is an
EVA latex polymer comprising from about 0% to about 45% by weight
of the cured binder and from about 0% to about 1.2% by weight of
the cured composite. In certain other embodiments, a
moisture-resistant cured MDF composite, HDF composite, or OSB
composite can be prepared containing a total binder level ranging
from about 1.5% to about 15%, from about 1.5% to about 11%, or from
about 2.5% to about 3.1%, by weight of the cured composite, wherein
the binder comprises a protein component (i.e., ground plant meal
or isolated polypeptide composition), an optional polymer latex
fraction, and a PMDI fraction with optional catalyst. In certain
embodiments, the PMDI component can be replaced with a
phenol-formaldehyde resin, lignin, or a combination thereof. In
other embodiments, PMDI can be used in combination with a
phenol-formladehyde resin, lignin, or both.
[0247] In another embodiment, a moisture-resistant cured particle
board composite can be prepared with a total binder level ranging
from about 1.5% to about 15%, from about 1.5% to about 11%, or from
about 1.2% to about 2.5%, by weight of the cured composite. The
binder comprises a protein component (i.e., ground plant meal or
isolated polypeptide composition), an optional polymer latex
fraction, and a PMDI fraction with optional catalyst. The PMDI
fraction comprises from about 0.1% to about 10%, from about 1.5% to
about 5%, or from about 0.1% to about 1.1% by weight of the cured
composite. In certain other embodiments, a moisture-resistant cured
MDF composite, HDF composite, or OSB composite can be prepared with
a total binder level ranging from about 1.5% to about 15%, from
about 1.5% to about 11%, or from about 1.2% to about 2.5%, by
weight of the cured composite. In certain embodiments, the PMDI
component can be replaced with a phenol-formaldehyde resin, lignin,
or a combination thereof. In certain other embodiments, PMDI can be
used in combination with a phenol-formaldehyde resin, lignin, or
both.
[0248] In the event that moisture-resistance is not a requirement
for the end-use application, cured composites can also be prepared
with a total binder level of less than approximately 5% by weight
of the cured composite, wherein the binder comprises a protein
component (i.e., ground plant meal or isolated polypeptide
composition) and a PMDI fraction with an optional catalyst. The
PMDI fraction can comprise from about 0.05% to about 2.5% (w/w) of
the cured composite. Depending upon the level of water that can be
tolerated during the manufacture of the composite, binder levels of
greater than 5% can also be employed, wherein the PMDI fraction
comprises at least 0.05% by weight of the cured composite. In
certain embodiments, the PMDI component can be replaced with a
phenol-formaldehyde resin, lignin, or a combination thereof. In
other embodiments, PMDI can be used in combination with a
phenol-formladehyde resin, lignin, or both.
[0249] Similar formulation considerations apply to the fabrication
and manufacture of plywood composites. For example,
moisture-resistant cured plywood assemblies can be laminated with
bondline adhesive levels ranging from approximately 0.008
pounds/ft..sup.2 up to approximately 0.056 pounds/ft..sup.2,
wherein the adhesive includes a protein component (i.e., ground
plant meal or isolated polypeptide composition), an optional
polymer latex fraction, and a PMDI fraction with an optional
catalyst. The PMDI can comprise from about 10% to about 80% (w/w),
or from about 20% to about 70% (w/w), of the cured adhesive. The
optional polymer latex can be an EVA polymer latex comprising
between about 0% and 45% of the cured binder. It is contemplated
that plywood composites prepared with these types of adhesive
compositions will be capable of withstanding boiling water and
hence will be extremely moisture resistant. In certain embodiments,
the PMDI component can be replaced with a phenol-formaldehyde
resin, lignin, or a combination thereof. In certain other
embodiments, PMDI can be used in combination with a
phenol-formaldehyde resin, lignin, or both.
Adhesive Composition Cure Temperature
[0250] Adhesives can be cured by allowing the adhesive to stand
under ambient conditions, or the adhesive may be cured by exposing
the adhesive to heat, pressure, or both. Furthermore, in certain
embodiments, these adhesives are stable but can cure when exposed
to moisture in air. In certain other embodiments, the adhesive
compositions are cold curable. In certain embodiments, the
adhesives include a cure catalyst (for example, DMDEE in the case
of adhesives containing a polyisocyanate) that facilitates curing
in the absence of applied heat. In certain embodiments, the
adhesives (for example, the polyisocyanate containing adhesives)
are cured in the presence of moisture at a temperature of about
10.degree. C. to about the ambient temperature range (25.degree.
C., to as high as 30.degree. C.). In certain other embodiments, the
cold cure temperature ranges from 20.degree. C. to 27.degree. C. In
other embodiments, the adhesives are hot cured, at temperatures
greater than 30.degree. C. Hot curing may at temperatures in the
range from 50.degree. C. to 300.degree. C., or from 90.degree. C.
to 275.degree. C., or from 110.degree. C. to 250.degree. C.
X. Applications of Adhesive Compositions
[0251] The adhesive compositions described herein can be used in a
variety of different applications, which include, for example,
bonding together many different types of substrates and/or creating
composite materials.
[0252] Accordingly, the invention provides a method of bonding a
first article to a second article. The method comprises the steps
of (a) depositing on a surface of the first article any one of the
foregoing adhesive compositions thereby to create a binding area;
and (b) contacting the binding surface with a surface of the second
article thereby to bond the first article to the second article.
The method optionally also comprises the step of, after step (b),
permitting the adhesive composition to cure, which can be
facilitated by the application of pressure, heat or both pressure
and heat.
[0253] The adhesive compositions can be applied to the surfaces of
substrates in any conventional manner. The surfaces can be coated
with the composition by spraying, brushing, doctor blading, wiping,
dipping, pouring, ribbon coating, or combinations of these
different methods, and the like.
[0254] The invention also provides a method of producing a
composite material. The method comprises the steps of (a) combining
a first article and a second article with any one of the foregoing
adhesive compositions to produce a mixture; and (b) curing the
mixture produced by step (a) to produce the composite material. The
curing can comprise applying pressure, heat or both pressure and
heat to the mixture.
[0255] The terms "substrate", "adherend" and "article" are
interchangeable and refer to the substances being joined, bonded
together, or adhered using the methods and compositions described
herein. In certain embodiments, the first article, the second
article or both the first and second articles are lignocellulosic
materials, or composite materials containing lignocellulosic
material. Furthermore, the first article, the second article or
both the first and second articles can comprise a metal, a resin, a
ceramic, a polymer, a glass or a combination thereof. It is
understood that the first article, the second article, or both the
first article and the second article can be a composite.
[0256] The compositions can be used to bond multiple
lignocellulosic materials (adherends) together to prepare composite
wood products. Furthermore, it is understood that at least one of
the adherends bonded together and/or included in the composite can
be wood, wood fiber, paper, rice hulls, fiberglass, ceramic,
ceramic powder, plastic (for example, thermoset plastic), cement,
stone, cloth, glass, metal, corn husks, bagasse, nut shells,
polymeric foam films or sheets, polymeric foams, fibrous materials,
or combinations thereof.
[0257] The amount of adhesive composition applied to the adhesive
bond between substrates may vary considerably from one end use
application, or type of adhesive used, or type of substrate, to the
next. The amount of adhesive should be sufficient to achieve the
desired bond strength and bond durability under a given set of test
conditions.
[0258] The amount of an adhesive composition applied may be in the
range of from about 5 to about 50 grams per square foot, from about
8 to about 60 grams per square foot, from about 10 to about 30
grams per square foot, from about 20 to about 50 grams per square
foot, from about 15 to about 40 grams per square foot, of bond
surface area (i.e., the bond surface area being the area of overlap
between the substrates to be bonded by the adhesive
composition).
[0259] The adhesive compositions can be used to fabricate
multi-substrate composites or laminates, particularly those
comprising lignocellulosic or cellulosic materials, such as wood or
paper. The adhesives can be used to prepare products such as
plywood, laminated veneer lumber (LVL), waferboard (also known as
chipboard or OSB), particle board, fiberboard, fiberglass,
composite wooden I-beams (I-joists), and the like.
[0260] The adhesive compositions can also be used to fabricate
composite materials, which include, for example, chip board,
particle board, fiber board, plywood, laminated veneer lumber,
glulam, laminated whole lumber, laminated composite lumber,
composite wooden I-beams, medium density fiberboard, high density
fiberboard, extruded wood, or fiberglass. The composite can be a
thermosetting composite or a thermoplastic composite. As described
above, the amount and identity of the components used to prepare
the composite can be selected to optimize the performance
properties of the composite. In one embodiment, the amount of
protein component is selected in order to optimize the performance
properties of the composite.
[0261] Accordingly, in certain other embodiments, the composite
comprises from about 0.5% to about 10% (w/w), from about 0.5% to
about 5% (w/w), from about 0.5% to about 3% (w/w), from about 1% to
about 10% (w/w), from about 1% to about 5% (w/w), or from about 1%
to about 3% (w/w) of ground plant meal or isolated polypeptide
composition. In certain other embodiments, the composite comprises
from about 0.1% to about 8% (w/w), from about 0.1% to about 5%
(w/w), from about 0.1% to about 3% (w/w), from about 0.5% to about
5% (w/w), from about 0.5% to about 3% (w/w), or from about 1% to
about 3% (w/w) of a polymeric material formed by reaction of the
prepolymer. In certain other embodiments, the composite comprises
from about 0.5% to about 10% (w/w), from about 0.5% to about 5%
(w/w), from about 0.5% to about 3% (w/w), from about 1% to about
10% (w/w), from about 1% to about 5% (w/w), or from about 1% to
about 3% (w/w) of formaldehyde scavenging agent (e.g.,
H.sub.2NC(O)NH.sub.2). In certain other embodiments, the composite
comprises from about 0.5% to about 10% (w/w), from about 0.5% to
about 5% (w/w), from about 0.5% to about 3% (w/w), from about 1% to
about 10% (w/w), from about 1% to about 5% (w/w), or from about 1%
to about 3% (w/w) of a diluent (e.g., glycerin, corn syrup, or a
mixture thereof). In certain other embodiments, the composite
comprises from about 0.001% to about 5% (w/w), from about 0.005% to
about 4% (w/w), from about 0.005% to about 2% (w/w), from about
0.05% to about 1% (w/w), from about 0.05% to about 2% (w/w), or
from about 0.05% to about 1% (w/w) of one or more additives, such
as an agent that improves moisture resistance, a pH modulator, a
composite-release promoter, tacking agent, fire retardant, or wood
preservative. In certain other embodiments, the composite comprises
from about 0.1% to about 8% (w/w), from about 0.1% to about 5%
(w/w), from about 0.1% to about 3% (w/w), from about 0.5% to about
5% (w/w), from about 0.5% to about 3% (w/w), or from about 1% to
about 3% (w/w) of lignin. In certain other embodiments, the
composite comprises from about 0.1% to about 8% (w/w), from about
0.1% to about 5% (w/w), from about 0.1% to about 3% (w/w), from
about 0.5% to about 5% (w/w), from about 0.5% to about 3% (w/w), or
from about 1% to about 3% (w/w) of a polymeric material formed by
reaction of a phenol-formaldehyde resin.
[0262] In certain embodiments, the composite (or other product
formed using an adhesive composition described herein) comprises
from about 0.5% w/w to about 20% w/w binder formed from the
adhesive composition. In certain other embodiments, the composite
(or other product formed using an adhesive composition described
herein) comprises from about 1% w/w to about 10% w/w, about 1% w/w
to about 5% w/w, about 1% w/w to about 4% w/w, about 2% w/w to
about 4% w/w, about 5% w/w to about 10% w/w, about 6% w/w to about
10% w/w, or about 6% w/w to about 8% w/w binder formed from the
adhesive composition. In yet other embodiments, the composite (or
other product formed using an adhesive composition described
herein) comprises less than about 20% w/w, about 15% w/w, about 10%
w/w, about 5% w/w, or about 1% w/w binder formed from the adhesive
composition.
[0263] In certain embodiments, the composite has an internal bond
strength of at least about 25 PSI, 40 PSI, 50 PSI, 70 PSI, 100 PSI,
120 PSI, or 150 PSI. In certain other embodiments, the composite
has a modulus of rupture of at least about 800, 900, 1000, 1100,
1200, 1300, 1400, or 1500 PSI. In certain other embodiments, the
composite has a modulus of rupture ranging from about 900 to about
1700 PSI, about 1000 to about 1700 PSI, about 1000 to about 1500
PSI, about 1100 to about 1700 PSI, about 1100 to about 1500 PSI, or
about 1200 to about 1500 PSI.
[0264] The adhesive composition can be mixed with cellulosic
components such as wood fiber, sawdust (sometimes referred to as
"furnish"), or other components, and then permitted to cured to
create a composite material. Alternatively, Parts A and B can be
mixed together before or during the addition of cellulosic
components. Mixing can be accomplished using conventional mixers
such as paddle mixers, static mixers and the like, currently known
in the art. In certain embodiments, the mixing is accomplished
using a high speed paddle mixing (e.g., with a Littleford blender
or a Henchel-type mixer), sigma-blade mixing, ribbon blending, etc.
Additional materials can also blended concurrently or sequentially
with the mixture including fillers such as calcium carbonate,
aluminosilicates, clays fumed silica, nano-sized inorganic
particulates, latex polymers, or antimicrobial compounds, etc.
[0265] Viscosity, sprayability, and/or spreadability of the
adhesive components can be controlled by adjusting the amount of
water added (or other liquid diluents such as glycerin and corn
syrup).
[0266] Adhesive compositions made using ground plant meal can
provide advantages in certain situations because the use of ground
plant meal allows for an adhesive composition comprising less
water. It is often desirable to use an adhesive composition
containing less water because cure of the adhesive may use elevated
temperatures which converts the water to steam, partially
complicating the procedures used to cure the adhesive. A related
benefit of using an adhesive composition containing ground plant
meal is that it permits more adhesive to be applied to the
components being bound together. This helps ensure that the
components being bound together are adequately coated with
adhesive, which facilitates strong bonding between the components
upon curing the adhesive.
[0267] Composite products can be prepared using a binder containing
a formaldehyde scavenging agent, such as urea. The amount of urea
can be adjusted based the on particular end-use application of the
composite, such as interior use (where more formaldehyde scavenging
agent is desired to minimize formaldehyde emissions) or exterior
use (where less formaldehyde scavenging agent may be acceptable
because the formaldehyde emission standards are less critical for
exterior applications).
[0268] Under certain circumstances, pressure and/or heat can be
used to facilitate curing. The amount of pressure and the time
period for which the pressure is applied are not limited and
specific pressures and times will be evident to one skilled in the
art from the present disclosure (see the various Examples). In
certain embodiments, a pressure of approximately 10 to 250 psi is
applied from about 2 minutes to about 2 hours, from about 10
minutes to about 2 hours, from about 2 minutes to about 30 minutes,
or from about 10 minutes to about 30 minutes (depending on the
temperature). The pressure, heating, or application of both
pressure and heat may decrease the viscosity adhesive compositions
described herein, facilitating their flow in the contact area, such
that a bonding region is created whereby there is a continuum
between the adherends. The amount of pressure, heat time or their
combination can be optimized to ensure such continuum and will
depend on the adherends' physical or chemical properties as well as
on the rate of the adhesive's viscosity-build throughout the cure
cycle.
[0269] Depending upon the adhesive used, the resulting article can
be moisture resistant. Furthermore, the article may remain intact
after boiling in water for 5 minutes, 10 minutes, 30 minutes, 1
hour, 2 hours, or 3 hours. Furthermore, two or more components of
the article may remain bonded after boiling in water for 5 minutes,
10 minutes, 30 minutes, 1 hour, 2 hours or 3 hours. Furthermore,
the article when boiled in water for 5 minutes, 10 minutes or 30
minutes, may display less than a 20% increase, or less than a 10%
increase in volume relative to the article prior to exposure to the
water.
[0270] Furthermore, when the article (for example, a composite
material, a laminate, or a laminate containing a composite
material) contains a lignocellulosic material, the article exhibits
no less than 75% cohesive failure of the lignocellulosic component
when the article is placed under a loading stress sufficient to
break the article. In certain embodiments, when an article
(resulting product) contains a lignocellulosic material, the
article has a block shear strength as measured under the D905 and
D2559 ASTM standards of greater than 3,000 lbs., 4,000 lbs., 5,000
lbs. or 6,000 lbs.
[0271] Additional adhesive compositions, emulsions, methods of
making adhesive compositions, methods of using adhesive
compositions, and articles are described in U.S. patent application
Ser. Nos. 12/719,521 and 13/154,607, the contents of which are
hereby incorporated by reference.
[0272] The description above describes multiple aspects and
embodiments of the invention, including adhesive compositions,
methods of using the adhesive compositions, and articles and
composites prepared using the adhesive compositions. The patent
application specifically contemplates all combinations and
permutations of the aspects and embodiments. Further, throughout
the description, where compositions are described as having,
including, or comprising specific components, or where processes
and methods are described as having, including, or comprising
specific steps, it is contemplated that, additionally, there are
compositions of the present invention that consist essentially of,
or consist of, the recited components, and that there are processes
and methods according to the present invention that consist
essentially of, or consist of, the recited processing steps.
[0273] Practice of the invention will be more fully understood from
the foregoing examples, which are presented herein for illustrative
purposes only, and should not be construed as limiting the
invention in any way.
EXAMPLES
Example 1
Isolation of Polypeptide Compositions
[0274] Exemplary procedures for isolating and characterizing the
water-insoluble polypeptide composition, water-soluble polypeptide
composition, or a mixture thereof are described below.
Procedure A: Preparation of Water-Insoluble Polypeptide Composition
and Preparation of Water-Soluble Polypeptide Composition.
[0275] Everlase digested protein from castor (experimental sample
lot 5-90) was obtained from Prof. S. Braun at the Laboratory of the
Department of Applied Biology at the Hebrew University of
Jerusalem, Israel. Digested castor can be prepared as follows:
castor meal protein is suspended in water at the ratio of about
1:10 w/w. Calcium chloride is added to an effective concentration
of about 10 mM, and the pH of the suspension adjusted to pH 9 by
the addition of 10 N NaOH. The reaction is then heated to
55.degree. C. while stirring. Next, Everlase 16L Type EX.RTM.
(NOVOZYMES') is added at the ratio of 20 g per kg of castor meal
protein, and the mixture is stirred at the same temperature for
about 4 hours. Finally, the resulting mixture is brought to a pH
3.5 with citric acid and spray-dried to provide a powder.
[0276] The Everlase digested protein from castor (lot 5-90) was
fractionated to yield a water-soluble fraction, and a
water-insoluble, dispersible fraction. In the first step, 300 g of
digested castor was slurried into 1 liter of distilled water. The
mixture was shaken by hand, and was then placed into a sonicator
bath for a period of 30 minutes. The slurry then was removed and
was allowed to set idle for a period of up to two days to allow the
insoluble portion to settle (in separate experiments, it was found
that centrifuging was equally adequate). At that point, the clear
yellow/amber supernatant was pipetted away and was retained for
future use. Fresh distilled water was then added to the sediment to
bring the total volume back to the 1-Liter mark on the container.
The process of shaking, sonicating, settling, supernatant
extracting, and replenishing with fresh distilled water (washing)
then was repeated (6 times in total). In the final step, the water
was pipetted from the top of the grayish-black sediment, and the
sediment was then dried in a vacuum oven at 45.degree. C. Based on
the sediment's dry weight, the water-insoluble/water-dispersible
polypeptide fraction was determined to comprise of approximately
50% by weight of the digested castor. Separately, the 1.sup.st and
2.sup.nd supernatants were combined and were then dried to yield a
transparent yellow-colored, water-soluble polypeptide fraction.
[0277] After drying the fractions, it was verified that the
grayish-black sediment (the water-insoluble and dispersible
fraction) could not be re-dissolved in water. On the other hand,
the dried supernatant fraction (clear/amber, glassy solid) was
completely soluble in water.
[0278] The two fractions were separately analyzed by solid state
FTIR (see FIGS. 2-4). The spectra in FIG. 2 show that carboxylate
and amine salt moieties are primarily associated with the
water-soluble fraction. FIG. 3 shows that the amide carbonyl
stretch band and the amide N--H bend bands are shifted to higher
wavenumbers in the water-soluble polypeptide fraction. These
components also appear to be present in the water-insoluble
dispersible polypeptide fraction, but the predominant amide-I and
amide-II bands are shifted to lower wavenumbers. Aside from
hydrogen bonding effects, these differences also appear to be
related to the presence of a higher fraction of primary amide
groups in the water-soluble polypeptide fraction, and to a higher
fraction of secondary amide groups in the water-dispersible
polypeptide fraction (from the main-chain polypeptide chains). This
is corroborated by the N--H stretching region depicted in FIG.
4.
[0279] FIG. 4 shows solid state FTIR spectra of isolated fraction
from digested castor where the N--H stretching region from FIG. 2
is expanded. The spectra were vertically scaled to achieve
equivalent absorbance intensities for the secondary amide N--H
stretch band centered at 3275 cm.sup.-1. FIG. 4 shows that the
predominant type of amide in the water-dispersible fraction is the
secondary main-chain amide as evidenced by the single, highly
symmetric band centered at 3275 cm.sup.-1. Although the
water-soluble fraction also contains this type of amide, it also
contains significantly higher fractions of primary amides as
evidenced by the presence of the two primary N--H stretching bands
at approximately 3200 cm.sup.-1 (symmetric) and at approximately
3300 cm.sup.-1 (asymmetric), respectively.
[0280] These spectra show that the water-soluble polypeptide
fraction contained a relatively high concentration of primary
amines, free carboxylic acids, acid salts, and amine salts.
Conversely, the water-insoluble/water-dispersible polypeptide
fraction had a higher fraction of secondary amides. In addition,
the amide-I carbonyl absorption band for the
water-insoluble/water-dispersible fraction was observed to appear
at a wavenumber of approximately 1625 cm.sup.-1, whereas that of
the water-soluble fraction was observed at approximately 1640
cm.sup.-1. As will be discussed elsewhere, this feature is one of
the distinguishing differences between the water-soluble and
water-insoluble polypeptide fractions; not only for castor
proteins, but for soy proteins and canola proteins as well.
Procedure B: Additional Procedure for Preparation of
Water-Insoluble Polypeptide Composition and Preparation of
Water-Soluble Polypeptide Composition.
[0281] Digested soy protein was obtained as an experimental sample
(lot 5-81) from Prof. S. Braun, the Laboratory of Applied Biology
at the Hebrew University of Jerusalem, Israel. The digested soy
protein was prepared as follows. Soy protein isolate (Soy protein
isolate SOLPRO 958.RTM. Solbar Industries Ltd, POB 2230, Ashdod
77121, Israel) was suspended in water at a ratio of 1:10 (w/w). The
pH of the suspension was adjusted to pH 7 with 10N NaOH, and was
then heated to 55.degree. C. while stirring. Neutrase 0.8 L.RTM.
(NOVOZYMES') then was added at a ratio of 20 g per kg of soy
protein, and the mixture was stirred at the same temperature for 4
hours. The resulting mixture (pH 6.5) was spray-dried to yield a
light tan powder.
[0282] Digested soy (lot 5-81) was fractionated to yield a
water-soluble polypeptide fraction, and a
water-insoluble/water-dispersible polypeptide fraction. In the
first step, 300 g of digested soy was slurried into 1 liter of
distilled water. The mixture was shaken by hand, and was then
placed into a sonicator bath for a period of 30 minutes. Aliquots
were placed into centrifuge tubes, and the tubes were then spun at
3,400 rpm for a period of approximately 35 minutes. The centrifuged
supernatant, which contained the water-soluble fraction, was
decanted off of the remaining water-insoluble sediment, and was
poured into a separate container for later use (this clear yellow
supernatant was placed into an open pan and was allowed to
evaporate dry at a temperature of 37.degree. C.). After the first
washing step, fresh distilled water was then added to the tubes,
and the remaining sediment was dispersed into the water by means of
hand-stirring with a spatula. The combined centrifugation,
decanting, and re-dispersion procedures were performed for a total
of 5 cycles. After the final cycle, the free liquid containing
residual water-soluble protein was decanted from the residual
paste-like dispersion (yellowish-peach in color). The resulting
dispersion (gravimetrically determined to be 16.24% solids by
weight) contained the water-insoluble/water-dispersible
proteins.
[0283] The paste-like dispersion was observed to be stable for a
period of several weeks. It was also discovered that the dispersion
could be readily combined with water-soluble polymers, and with
water-dispersible polymer latexes. Moreover, the dispersion was
readily compatible with PMDI (a stable dispersion was formed when
PMDI was added to the slurry, and there was no evidence of PMDI
phase separation, even after 24 hours). By contrast, neither the
water soluble extract from the digested soy, nor the digested soy
itself was capable of stabilizing a dispersion of PMDI in
water.
[0284] After drying aliquots of both fractions, it was verified
that the yellow sediment (the water-insoluble/water-dispersible
extract) could not be re-dissolved in water. On the other hand, the
dried supernatant fraction (clear/yellow solid) was completely
soluble in water. The two dried extracts were separately analyzed
by solid state FTIR (see FIGS. 5-8). FIG. 6 shows overlaid solid
state FTIR spectra of isolated fractions from digested soy, where
the N--H region is expanded. The spectra were vertically scaled to
achieve equivalent absorbance intensities for the secondary amide
N--H stretch band centered at 3275 cm.sup.-1. FIG. 6 shows that the
predominant type of amide in the water-dispersible fraction is the
secondary main-chain amide as evidenced by the single, highly
symmetric band centered at 3275 cm.sup.-1. Although the
water-soluble polypeptide fraction also contains this type of
amide, it also contains significantly higher fractions of primary
amides as evidenced by the presence of the two primary N--H
stretching bands at approximately 3200 cm.sup.-1 (symmetric) and at
approximately 3300 cm.sup.-1 (asymmetric), respectively.
Collectively, these spectra revealed that the water-soluble
polypeptide fraction was comprised of a relatively high
concentration of primary amines. Conversely, the water-insoluble,
dispersible polypeptide fraction was comprised of a higher fraction
of secondary amines.
[0285] As shown in FIG. 5, the amide carbonyl stretch band and the
amide N--H bend band are shifted to higher wavenumbers in the
water-soluble fraction. These components also appear to be present
in the water-insoluble dispersible fraction, but the predominant
amide-I and amide-II bands are shifted to lower wavenumbers. Aside
from hydrogen bonding effects, these differences appear to be
related to the presence of a higher fraction of primary amide
groups (and/or primary amines) in the water-soluble polypeptide
fraction (from lower molecular weight amino acid fragments), and to
a higher fraction of secondary amide groups in the
water-dispersible polypeptide fraction (from the main-chain
polypeptide chains). This is supported by the N--H stretching
region depicted in FIG. 4.
[0286] FIG. 6 shows that the predominant type of amide in the
water-dispersible fraction is the secondary main-chain amide as
evidenced by the single, highly symmetric band centered at 3275
cm.sup.-1. Although the water-soluble fraction also contains this
type of amide, it also contains significantly higher fractions of
primary amines as evidenced by the presence of the two primary N--H
stretching bands at 3200 cm.sup.-1 (symmetric) and at approximately
3300 cm.sup.-1 (asymmetric), respectively.
[0287] In spite of being derived from different plant sources, the
water-insoluble dispersible fractions from digested soy and
digested castor are spectrally similar to one another (see FIG.
12). Conversely, the water-soluble polypeptide fractions appear to
have different FTIR spectral characteristics (see FIG. 10).
Further, MALDI mass spectroscopic indicates the water-soluble
polypeptide fractions from digested soy and digested castor have
different molecular weight characteristics. The commonality between
the two types of water-soluble fractions is that they both appear
to contain primary amines/amides.
Procedure C: Additional Procedure for Preparation of
Water-Insoluble Polypeptide Composition and Preparation of
Water-Soluble Polypeptide Composition
[0288] Castor meal (4.0 kg containing 24.8% protein) was suspended
in 0.1M NaOH at a 10:1 w/w meal to alkali ratio. The suspension was
stirred for 18 hours at ambient temperature and the solids were
then removed by centrifugation. The supernatant (about 32 liters)
was acidified to pH 4.5 with 10 N HCl. The protein was allowed to
sediment at about 10.degree. C. for 12 hours, the clear supernatant
solution was decanted, and the heavy precipitate (about 2 kg) was
collected by centrifugation. The wet precipitate was freeze-dried
yielding 670 g protein isolate.
[0289] The water-insoluble and water-soluble polypeptide fractions
were obtained by means of extraction with water. In the first step,
10 g of the castor protein isolate (lot 5-94) was slurried into 50
g of distilled water. The mixture was dispersed via mechanical
stirring for 2 hours. Aliquots then were placed into centrifuge
tubes, and the tubes were then spun at 3,400 rpm for a period of
approximately 35 minutes. The centrifuged supernatant, which
contained the water-soluble fraction, was decanted from the
remaining water-insoluble sediment, and was poured into a separate
container (this clear yellow supernatant was saved and dried at
37.degree. C. for subsequent dispersion experiments and solid state
FTIR analyses). After the first washing step, fresh distilled water
was then added to the tubes, and the remaining sediment was
dispersed into the water by means of hand-stirring with a spatula.
The combined centrifugation, decanting, and re-dispersion
procedures were performed for a total of 13 cycles. After the final
cycle, the free liquid was decanted from the residual paste-like
dispersion (the water-insoluble polypeptide fraction from the
starting castor protein). Upon drying, the paste was determined to
contain 28.58% solids, and the total yield of the water-insoluble
fraction was determined to be 62.87%. Thus, the starting castor
protein itself contained 62.87% water-insoluble polypeptide
material, and 37.12% water-soluble polypeptide material.
Procedure D: Preparation of Digested Whey Protein.
[0290] Digested whey protein (lot 5-72, referred to herein as
digested whey protein pH 6.5) was obtained as an experimental
sample from Prof. S. Braun, the Laboratory of Applied Biology at
the Hebrew University of Jerusalem, Israel, and was prepared as
follows; Whey protein (WPI-95.RTM. Whey Protein Isolate;
Nutritteck, 24 Seguin Street, Rigaud, QC, Canada J0P 1P0) was
suspended in water at a ratio of 1:6 (w/w). The pH of the
suspension was adjusted to pH 7 with 5N NaOH, and was heated to
55.degree. C. while stirring. FLAVOURZYME 500MG.RTM. (from
NOVOZYMES') then was added at a ratio of 20 g per kg of whey
protein, and the mixture was stirred at the same temperature for 4
hours. The resulting aqueous mixture was pH 6.5. The resulting
mixture then was spray-dried to yield digested whey protein as a
pale yellow powder containing a mixture of water-soluble and
water-insoluble polypeptide.
Procedure E: Preparation of Digested Castor Protein Reacted with
Sodium Nitrite.
[0291] Castor meal protein was suspended in water at a ratio of
1:10 (w/w). Calcium chloride was added at an effective
concentration of 10 mM, and the pH of the suspension was adjusted
to pH 9 by the addition of 10 N NaOH. The reaction was heated to
55.degree. C. while stirring. Everlase 16L Type EX.RTM.
(NOVOZYMES') then was added at a ratio of 10 g per kg of castor
meal protein, and the mixture was stirred at the same temperature
for 4 hours. L-lactic acid (90%, 120 g per kg castor protein) then
was added to bring the mixture to pH 4.4 followed by gradual
addition (over a 20 hour period) of sodium nitrite solution in
water (0.4 kg/1, 0.4 liter per kg castor protein) while stirring.
The reaction then was left to stand at ambient temperature for 40
hours. Na.sub.2S.sub.2O.sub.5 (0.2 kg per kg castor protein) was
then added, and the reaction was heated to 60.degree. C. and
stirred for 15 minutes. After cooling to ambient temperature, the
reaction was brought to pH 2.0 with concentrated HCl. It was then
left at 10.degree. C. for 18 hours, and the resulting precipitate
was separated by centrifugation for 15 minutes at 24,000.times.g.
The precipitate was re-suspended in 10 mM citric acid (3 vol. per
vol. precipitate), and then it was collected and subsequently
freeze-dried to yield a tan powder containing a mixture of
water-soluble and water-insoluble polypeptide.
Procedure F: Isolation of Water-Insoluble/Water-Dispersible Protein
Fraction and Water-Soluble Protein Fraction by Washing Ground Soy
Meal with Water, and Characterization of Same
Part I: Isolation of Water-Insoluble/Water-Dispersible Protein
Fraction and Water-Soluble Protein Fraction
[0292] Soy meal (same as Example 1) having a particle size range of
20-70 .mu.m was mixed with distilled water (pH approximately 7) to
yield a 27.83% meal dispersion in water (w/w). In the first "wash"
step, an aliquot of the dispersion was centrifuged for 60 minutes,
and the clear supernatant containing a water-soluble protein
fraction was decanted from the wet slurry that remained on the
bottom of the centrifuged tube (in a separate experiment, this wet
slurry was gravimetrically determined to contain approximately 33%
solids in water (w/w); and the supernatant was gravimetrically
determined to contain approximately 15% by weight solids (w/w)).
The yield of the water-insoluble/water-dispersible protein fraction
after the first "wash" step was determined to be approximately 80%
of the starting meal weight.
[0293] In a second step, the 33% solids fraction from the first
wash step was mixed and dispersed in fresh distilled water (pH
approximately 7), and the dispersion was centrifuged for a second
time. Again, the clear supernatant was decanted, and the remaining
slurry was subjected to a third wash cycle (addition of fresh
distilled water followed by centrifuging). After the third "wash"
step and supernatant decanting, the resulting slurry of
water-insoluble/water-dispersible protein fraction was
gravimetrically determined to contain approximately 24% solids, and
the yield was determined to be approximately 53% of the starting
meal weight. Thus, the ground soy meal itself was comprised of
approximately 53% of a water-insoluble/water-dispersible protein
fraction, and approximately 47% of a water-soluble protein
fraction.
Part II: Disperion Analysis for Water-Insoluble/Water-Dispersible
Protein Fraction, Water-Soluble Protein Fraction, and Ground Soy
Meal
[0294] An aliquot of the 24% solids dispersion of the isolated
water-insoluble/water-dispersible protein fraction (washed 3 times
as noted above) was blended with PMDI at a w/w ratio of 1 part PMDI
to 1 part of protein fraction. The resulting mixture formed a
stable dispersion, and remained stable during a 1 hour period of
observation with no visual signs of phase separation.
[0295] In order to test dispersion ability of ground soy meal, a
dispersion of 24% (w/w) ground soy meal in water was mixed with
PMDI at a 1:1 w/w ratio of PMDI to soy meal solids. The soy meal
comprised approximately 53% by weight of a
water-insoluble/water-dispersible protein fraction and
approximately 47% by weight of a water-soluble protein fraction.
The mixture of ground meal and PMDI formed a stable dispersion
which remained stable during a 1 hour period of observation with no
visual signs of phase separation.
[0296] In order to test dispersion ability of water-soluble protein
faction, water-soluble protein fraction obtained from the soy meal
(by first washing the soy meal, then isolating the water-soluble
fraction by drying the supernatant after centrifuging) was
dissolved in water to yield a 24% solids solution (w/w). When PMDI
was added to this solution (at a 1:1 weight ratio of PMDI to
water-soluble protein fraction), the resulting mixture was
unstable, and phase separation was visually evident--immediately
after mixing.
[0297] The experimental results above demonstrate that
water-emulsified PMDI-containing adhesive compositions can be
prepared with i) water-insoluble/water-dispersible protein
fractions obtained by washing ground plant meals, and ii) ground
plant meal compositions that are comprised of both a
water-insoluble/water-dispersible protein fraction and a
water-soluble protein fraction. The water-soluble protein fraction
does not facilitate dispersion, but the
water-insoluble/water-dispersible protein fraction is present in an
amount sufficient to facilitate dispersion.
[0298] Various commercially available compositions derived from
plant meals, such as soy flour, are solvent-extracted which result
in removal of water-insoluble protein components. Such compositions
are unable to facilitate dispersion, and, thus, are less desirable
for use making an adhesive.
Part III: FTIR Analysis of Water-Insoluble/Water-Dispersible
Protein Fraction, Water-Soluble Protein Fraction, and Ground Soy
Meal
[0299] Solid state surface ATR FTIR experiments were performed on
water-insoluble/water-dispersible protein fraction (this sample was
collected after the third wash cycle and was allowed to dry at
23.degree. C., and water-soluble protein fraction (this sample was
collected from the clear supernatant after the third wash cycle,
and was allowed to dry at 23.degree. C. to yield a transparent
amber solid) obtained by washing soy meal with water.
Characteristics of the FTIR spectra are described below.
[0300] FIG. 16 shows the solid state FTIR spectra for the isolated
water-insoluble/water-dispersible protein fraction from soy meal
together with the water-soluble protein fraction where the N--H
stretching region has been expanded. The spectra were vertically
scaled to achieve equivalent absorbance intensities for the
secondary amide N--H stretch band centered at 3275 cm.sup.-1. FIG.
16 shows that the predominant type of amide in the
water-insoluble/water-dispersible protein fraction is the secondary
main-chain amide as evidenced by the single, highly symmetric band
centered near 3275 cm.sup.-1. Although the water-soluble fraction
also contains this type of amide, it also contains significantly
higher fractions of primary amides as evidenced by the presence of
the two primary N--H stretching bands at approximately 3200
cm.sup.-1 (symmetric) and at approximately 3300 cm.sup.-1
(asymmetric), respectively.
[0301] As shown in FIG. 17, the amide-I carbonyl absorption band
for the water-insoluble/water-dispersible protein fraction was
observed to appear at a wavenumber of approximately 1629 cm.sup.-1,
whereas that of the water-soluble protein fraction was observed to
appear at approximately 1650 cm.sup.-1. This feature is one of the
distinguishing differences between the water-soluble protein
fraction and water-insoluble/water-dispersible protein fraction,
not only for isolated polypeptides from castor and soy proteins,
but for protein-containing fractions that are isolated directly
from plant meals like soy meal. Moreover, the amide-II band for the
water-insoluble/water-dispersible protein fraction was observed to
appear as a broad band centered at approximately 1526 cm.sup.-1,
whereas that of the water-soluble protein fraction was observed to
appear at approximately 1580 cm.sup.-1 together with a weak
shoulder at approximately 1547 cm.sup.-1.
Example 2
Characterization of Polypeptide Compositions by Mass
Spectrometry
[0302] This Example describes characterization of the various
protein samples via MALDI Mass Spectrometry using an Ultraflex III
instrument from Bruker.
[0303] The instrument was set in positive mode, in order to detect
positive ions generated during the ionization process. The voltage
applied to accelerate the ion into the TOF analyzer was set at 25
KV. The analysis was carried out by using the instrument in
reflection mode which improves the resolution. Solid samples were
dissolved in DMSO at a concentration of 10 mg/mL. Water-soluble
supernatant fractions which were solvated in water.
[0304] Each sample solution was mixed with a matrix solution (for
analytical purposes). The matrix was an inert compound of low
molecular weight which absorbs at the same wavelength of the laser,
Nd:YAG 355 nm. The matrices used were: .alpha.-CHCA,
alpha-cyano-4-hydroxycinnamic acid, dissolved in a solution of
ACN/H.sub.2O (70:30) with 0.1% of TFA at a concentration of 10
mg/mL; and DCTB,
T-2-[3-(4-t-Butyl-phenyl)-2-methyl-2-propenylidene]malononitrile,
dissolved in THF at a concentration of 10 mg/mL. The first matrix
was mainly used for the analysis of peptides and proteins while the
second one, DCTB, was suitable for the analysis of polymers.
[0305] The matrix solutions and the sample solutions were mixed at
a 10:1 volume ratio respectively. For the analysis where DCTB was
used as matrix, NaTFA (10 mg/mL in THF) was added to the solution
matrix/sample as a cationizing agent at a ratio 10:2:1 by volume
(matrix:sample:salt, respectively). 0.8 .mu.L of the resulting
solutions were spotted on a target plate made of polished steel,
and only after the solvents were completely dried was the target
loaded into the instrument. The spectra were collected and
manipulated by using FlexAnalysis software released by Bruker
Daltonics.
[0306] Relative fragment intensities were normalized and used to
calculate number average (Mn), weight average (Mw), and z-average
(Mz) molecular weight parameters for various samples. The results
are summarized in Table 2.
TABLE-US-00002 TABLE 2 Sample ID Mn Mw Mz Mw/Mn Castor protein
isolate lot 5-94 .sup.1 1149 1162 1179 1.01 Digested castor lot
5-83 .sup.2 951 1081 1250 1.13 Digested castor lot 5-108 .sup.3 897
1011 1169 1.12 Digested castor Water-insoluble/ 1009 1371 1928 1.35
dispersible fraction (lot 5-108) .sup.3 Digested castor
Water-soluble fraction 1532 1697 1894 1.10 (lot 5-108) .sup.3 Soy
Protein Isolate 2023 2104 2161 1.03 Digested Soy (lot 5-81) .sup.4
894 989 1104 1.10 Digested Soy Water-insoluble/dispersible 910 1119
1512 1.22 fraction (lot 5-81) .sup.4 Digested Soy Water-soluble
fraction 837 888 941 1.06 (lot 5-81) .sup.4 .sup.1 see Example 1,
Procedure C .sup.2 Castor meal protein digested with Everlast (Lot
No. 5-83) was obtained from Prof. Sergei Braun of The Hebrew
University of Jerusalem .sup.3 see Example 4 .sup.4 see Example 1,
Procedure B
[0307] The results indicate that the molecular weight
characteristics (as determined by MALDI mass spectroscopy) of the
polypeptide composition can depend on the process used to obtain
the polypeptide composition. For example, castor protein isolate
was observed to have a higher number average molecular weight than
its digested counterpart. Further, upon digestion, the number
average molecular weight was observed to decrease while the
polydispersity increased. The same trend was observed for the soy
protein isolate and its digested counterpart.
[0308] Other experimental results indicate that proteins in the
water-soluble polypeptide composition from digested castor have a
higher number average molecular weight than its parent protein
isolate. However, proteins in the water-soluble polypeptide
composition from digested soy had a lower number average molecular
weight than its parent soy protein isolate.
[0309] Collectively, these results indicate that it is possible to
prepare compositions that both i) have particular molecular weight
features, and ii) have the ability to disperse an oil in water or
water in oil, by selecting a particular procedure for preparing the
polypeptide composition.
Example 3
Characterization of Polypeptide Compositions by Two-Dimensional
Proton-Nitrogen NMR Correlation Spectra and Characterization of a
Water-Insoluble/Water-Dispersible Polypeptide Fraction
[0310] The water-insoluble and water-soluble protein fractions were
prepared as follows. Digested castor (lot 5-83) was suspended in
water at the ratio of 1:10 w/w. Calcium chloride was added to the
effective concentration of 10 mM, and the pH of the suspension was
adjusted to pH 9 by the addition of 10 N NaOH. The reaction was
heated to 55.degree. C. while stirring. Everlase 16L Type EX.RTM.
(NOVOZYMES') then was added at the ratio of 10 g per kg of castor
meal protein, and the mixture was stirred at the same temperature
for 4 hours. The resulting mixture then was brought to a pH 3.5
with citric acid and was spray-dried to yield a tan powder. Then,
the water-insoluble and water-soluble protein fractions were
harvested as described in Example 1 (Procedure A) and were allowed
to air-dry at 23.degree. C.
[0311] The dried powder containing the water-insoluble protein
fraction was dissolved in d6-DMSO (6.8% by weight) to yield a red
homogeneous solution (Sample A). An aliquot of the as-made dried
digested castor was also dissolved in d6-DMSO (6.8% solids by
weight) to yield a comparative homogeneous red solution (Sample B).
Solid-state FTIR analyses of the same dried powders revealed
distinct differences in both the N--H stretching and carbonyl
stretching regions of the solid state FTIR spectra. These spectral
differences were attributed to differences in bonding environments
for the polypeptide N--H moieties, possibly resulting from
differences in secondary and tertiary structure. One of the
specific differences involved a shift to lower wavenumbers for the
amide-I carbonyl band in the water-insoluble/water-dispersible
fraction. In order to further characterize these types of
differences, a two-dimensional NMR technique was employed for the
purpose of characterizing a very specific subset of bonded atomic
nuclei; namely, protons bonded to nitrogens.
[0312] The samples were dissolved in DMSO-d6 and were placed into 5
mm NMR tubes. All .sup.1H NMR spectra were recorded on a Varian
INOVA 750 MHz spectrometer equipped with an HCN--PFG (pulsed field
gradient) triple resonance Cryo Probe at 30.degree. C. For
one-dimensional (1D) .sup.1H NMR spectra, a spectral window of
10000 Hz was used with an acquisition time of 3 seconds and
relaxation delay of 5 seconds. The spectra were signal averaged for
16 transients using a proton 90.degree. pulse width of 8.6
microseconds. The spectral data were zero filled to 132k points and
were processed with 1 Hz line broadening, then baseline corrected
and referenced to an internal residual solvent DMSO-d6 peak at 2.50
ppm before integrating and making plots.
[0313] Phase sensitive two-dimensional (2D) .sup.1H--.sup.15N
gradient-HSQC (heteronuclear single quantum coherence) data were
collected with 2048 acquisition points in the F2 dimension and 768
points in the F1 dimension (90.degree. pulse widths of 6.3
microseconds, and 33.5 microseconds were used for proton and
nitrogen, respectively) 48 transients were collected for each
increment, with a repetition delay of 1.2 seconds and acquisition
time of 0.124 seconds with GARP decoupling during acquisition. The
acquired data were processed with sine bell weighting and zero
filled to 8196.times.8196 points in F2 and F1 dimensions before
final transformation to produce the 2D correlation data.
[0314] The results are presented in FIGS. 13-15. FIG. 13 represents
the two-dimensional HSQC .sup.1H--.sup.15N NMR spectrum for
digested castor lot 5-83 in d6-DMSO. The y-axis represents .sup.15N
chemical shift scale (ppm), and the x-axis represents .sup.1H
chemical shift scale (ppm). The peaks within the spectrum represent
protonated nitrogen atoms from all of the fractions that were
present within the as-made digested castor (i.e., the
water-insoluble/water-dispersible polypeptide fractions plus the
water-soluble polypeptide fractions). The multiple peaks in region
B were observed to disappear upon removal of the water-soluble
fractions (see FIG. 14). This indicates that these protonated
nitrogens are specific to the water-soluble polypeptide fractions,
whereas at least a portion of the peaks in region A are specific to
the water-insoluble/water-dispersible fraction.
[0315] FIG. 14 represents the two-dimensional HSQC
.sup.1H--.sup.15N NMR spectrum for the
water-insoluble/water-dispersible polypeptide extract from digested
castor lot 5-83 in d6-DMSO. The y-axis represents .sup.15N chemical
shift scale (ppm), and the x-axis represents .sup.1H chemical shift
scale (ppm). The peaks within the spectrum represent protonated
nitrogen atoms from the water-insoluble/water-dispersible
polypeptide fraction. The peaks within Region B were observed to be
very weak in comparison to the analogous peaks within the digested
castor before extraction (see FIG. 13). Conversely, the remaining
peaks were predominantly from the protonated nitrogens in Region A.
This indicates that these particular protonated nitrogens are
specific to the water-insoluble polypeptide fractions. A magnified
view of this region is presented in FIG. 15.
[0316] As shown in FIG. 14, the peaks within the spectrum represent
protonated nitrogen atoms that are specific to the
water-insoluble/water-dispersible polypeptide fraction. Upon
expansion, the two "peaks" appear as narrow clusters that can be
readily defined by the .sup.15N and .sup.1H chemical shift
boundaries that define them: the .sup.15N boundaries for both
clusters occur at approximately 86.2 ppm and 87.3 ppm; and the
.sup.1H boundaries occur at approximately 7.14 and 7.29 ppm for the
first cluster; and at approximately 6.66 and 6.81 ppm for the
second cluster.
[0317] The results of these studies revealed that while the
water-soluble polypeptide fraction was composed of multiple types
of protonated nitrogen atoms (see FIG. 13), the
water-insoluble/water-dispersible fraction contained significantly
fewer types of protonated nitrogens, and was predominantly
characterized by the presence of two major proton-nitrogen cross
peak clusters (see FIG. 14). These differences, like those as seen
by solid state FTIR, illustrate that the chemical bonding
environments within the water-soluble polypeptide fraction are
distinctly different from those that exist within the
water-insoluble/water-dispersible fraction.
[0318] Together, the solid state FTIR and NMR data characterize the
water-insoluble/water-dispersible polypeptide fraction, where there
is a solid-state infrared amide-I absorption band between 1620-1632
cm.sup.-1; a solid-state infrared amide-II absorption band between
1514-1521 cm.sup.-1; and a solution-state pair of protonated
nitrogen clusters as determined by a .sup.1H--.sup.15N nuclear
magnetic resonance correlation technique. More specifically, when
the pair of protonated nitrogen clusters is observed by means of
NMR with deuterated d6-DMSO as the solvent using a two-dimensional
HSQC .sup.1H--.sup.15N NMR technique, the clusters are defined by
the .sup.15N and .sup.1H chemical shift boundaries that define
them: the .sup.15N boundaries for both clusters occur at
approximately 86.2 ppm and 87.3 ppm; and the .sup.1H boundaries
occur at approximately 7.14 and 7.29 ppm for the first cluster; and
at approximately 6.66 and 6.81 ppm for the second cluster.
[0319] Together, the solid state FTIR and NMR data also
characterize the water-soluble polypeptide fraction, where there is
a solid-state infrared amide-I absorption band between about
1633-1680 cm.sup.-1; a solid-state infrared amide-II absorption
band between 1522-1560 cm.sup.-1; two prominent 1.degree. amide
N--H stretch absorption bands centered at about 3200 cm.sup.-1, and
at about 3300 cm.sup.-1, as determined by solid state FTIR, and a
prominent cluster of protonated nitrogen nuclei defined by .sup.15N
chemical shift boundaries at about 94 ppm and at about 100 ppm, and
.sup.1H chemical shift boundaries at about 7.6 ppm and at about 8.1
ppm, as determined by solution state, two-dimensional
proton-nitrogen coupled NMR.
Example 4
Oil Dispersion Characteristics of Water-Soluble and
Water-Insoluble/Water-Dispersible Protein Fractions
[0320] A water-insoluble/water-dispersible polypeptide fraction and
a water-soluble polypeptide fraction were isolated from digested
castor (lot 5-108) based on procedures described in Example 1
(Procedure A). The digested castor can be prepared as follows:
castor meal protein is suspended in water at the ratio of about
1:10 w/w. Calcium chloride is added to an effective concentration
of about 10 mM, and the pH of the suspension adjusted to pH 9 by
the addition of 10 N NaOH. The reaction is then heated to
55.degree. C. while stirring. Next, Everlase 16L Type EX.RTM.
(NOVOZYMES') is added at the ratio of 10 g per kg of castor meal
protein, and the mixture is stirred at the same temperature for
about 4 hours. Finally, the resulting mixture is brought to a pH
3.5 with citric acid and spray-dried to provide a powder.
[0321] The MALDI fragmentation molecular weight characteristics of
the isolated fractions are provided in Example 2. The solid state
FTIR spectroscopic absorption characteristics for the isolated
water-insoluble/water-dispersible polypeptide fraction conform with
those as described in FIGS. 2-4, 7, and 9-12 (amide-I absorption
range: 1620-1632 cm.sup.-1; amide-II absorption range: 1514-1521
cm.sup.-1). Solution state two-dimensional proton-nitrogen coupled
NMR on the isolated water-insoluble/water-dispersible polypeptide
fraction show two protonated nitrogen clusters enveloped by
.sup.15N chemical shift boundaries at approximately 86.2 ppm and
87.3 ppm; and with .sup.1H chemical shift boundaries at
approximately 7.14 and 7.29 ppm for the first cluster; and at
approximately 6.66 and 6.81 ppm for the second cluster. Solution
state two-dimensional proton-nitrogen coupled NMR on the isolated
water-soluble polypeptide fraction show a cluster of protonated
nitrogen nuclei defined by .sup.15N chemical shift boundaries at
about 94 ppm and at about 100 ppm, and .sup.1H chemical shift
boundaries at about 7.6 ppm and at about 8.1 ppm.
[0322] The water-insoluble/water-dispersible polypeptide fractions
with these spectral characteristics (unlike their water-soluble
counterparts) exhibit the unique ability to emulsify and stabilize
dispersions of oil in water and water in oil. This unique
oil-dispersing capability is observed with
water-insoluble/water-dispersible polypeptide compositions that are
extracted and isolated from multiple sources, including but not
limited to (1) whole meals or protein-isolates from either soy,
canola, or castor that are extracted of their water-soluble
polypeptide components at or near pH-neutral conditions; (2) whole
meals or protein-isolates from soy, canola or castor that are
subjected to base catalyzed hydrolysis followed by acid addition
and subsequent extraction of water-soluble polypeptide components;
(3) whole meals or protein-isolates from soy, canola or castor that
are subjected to acid catalyzed hydrolysis followed by base
addition and subsequent extraction of their water-soluble
polypeptide components; (4) whole meals or protein-isolates from
soy, castor, or canola that are subjected to combinations of base
catalyzed hydrolysis with enzyme digestion followed by acid
addition and subsequent extraction of water-soluble polypeptide
components.
[0323] It is understood that the stabilization of an oil-in-water
or water-in-oil emulsion/dispersion depends on several factors,
including but not limited to the presence or absence of a
stabilizing entity such as a surfactant or a dispersant; the nature
of the oil (i.e., its polarity, hydrophilicity, hydrophobicity,
solubility parameter, etc.); the nature of the surfactant or
dispersant (i.e., HLB value, charge characteristics, molecular
weight, water solubility, oil solubility, etc.); the ionic strength
of the water-phase; the presence or absence of additives and
impurities in either the oil or water phases; the concentration of
the oil (i.e., its weight percent in water); and the concentration
of the stabilizing entity. It is further understood that the
efficiency of a stabilizing entity (a "stabilizing entity" being a
dispersant, an emulsifier, a surfactant, or the
water-insoluble/water-dispersible polypeptide composition of the
present invention) is often judged according to its ability
stabilize an emulsion for some specified period of time (i.e., to
prevent the macroscopic phase separation of immiscible oil and
water components under shear or under static conditions).
[0324] In order to further demonstrate the generality of this
finding, several oil-in-water dispersions were prepared with a
water-insoluble/water-dispersible polypeptide composition that was
isolated from a digested castor protein. The
water-insoluble/water-dispersible polypeptide fraction was isolated
as a paste-like dispersion in water. The paste was diluted with
water to 16% solids, and separately to 14% solids. In the next
step, 3-gram aliquots of each paste were separately weighed into 15
mL plastic beakers. Next, aliquots of the oils shown in Table 3
were separately added to individual paste aliquots at a ratio of 1
part oil to 1 part solid water-insoluble/water-dispersible
polypeptide composition on a weight basis (20 mixtures in total).
The mixtures were stirred by hand with a spatula, and were observed
to form homogenous creams. The creams remained homogeneous with no
visible signs of macroscopic phase separation for prolonged periods
of time after mixing including periods ranging from 1 minute after
mixing, 5 minutes after mixing, 10 minutes after mixing, 15 minutes
after mixing, 30 minutes after mixing, 1 hour after mixing, and 2
hours after mixing. By contrast, the analogous water-soluble
extract from the digested castor was incapable of stabilizing
dispersions of the oils in water.
TABLE-US-00003 TABLE 3 Oil Type Source PMDI Rubinate-M from
Huntsman Corporation Mineral oil Drakeol 35 from Penreco Soybean
oil RBD from ADM Processing Co. Motor oil Castrol Syntec, 5W-50
Castor oil Pale Pressed Castor Oil from Alnor Oil Company, Inc.
Dibutyl Phthalate 99% from Acros Epoxidized soybean oil From
Aldrich Caprylic triglyceride Neobee M-5 from Stepan Co. Eucalyptus
oil From Aromas Unlimited Tributyl o-acetylcitrate 98% from
Aldrich
[0325] Protein compositions not enriched for the
water-insoluble/water-dispersible fractions are unable to disperse
oils. For example, a 16% solids dispersion of soy protein isolate,
Lot 5-81, (Soy protein isolate SOLPRO 958.RTM. Solbar Industries
Ltd, POB 2230, Ashdod 77121, Israel; protein content approximately
90%) was prepared by adding 32 grams of soy protein isolate to 168
grams of water at a pH of approximately 4 to 6 (JM-570-1). Seven 10
gram aliquots of JM-570-1 were weighed into 20 mL disposable
beakers. A 10 gram aliquot contained 1.6 grams of soy protein
isolate and 8.4 grams of water. Seven different oils (namely, PMDI,
mineral oil, soybean oil, motor oil, castor oil, dibutyl phthalate
and epoxidized soybean oil) were added separately at a w/w ratio of
1 part oil to 1 part protein solids (1.6 grams oil was added to
each 10 gram aliquot). The mixtures were stirred by hand with a
spatula. None of the oils was observed to be dispersible in the 16%
solids dispersion of the soy protein isolate.
Example 5
Physical Characterization by Gravimetric Analysis, FTIR
Spectroscopy, and Oil-Dispersing Capacity of Ground Canola Meal,
Water-Insoluble/Water-Dispersible Protein Fraction Extracted from
Ground Canola Meal, and Water-Soluble Protein Fraction Extracted
from Ground Canola Meal
[0326] Ground canola meal, a water-insoluble/water-dispersible
protein fraction that was extracted from ground canola meal, and a
water-soluble protein fraction that was extracted from ground
canola meal were subjected to physical characterization by
gravimetric analysis, FTIR Spectroscopy, and ability to disperse
oil. Experimental procedures and results are provided below.
General Experimental Procedure:
[0327] Water-insoluble/water-dispersible protein fraction and
water-soluble protein fraction were isolated from ground canola
meal using the isolation method described in Procedure F of Example
1. FTIR spectra were obtained using solid state FTIR procedures
outlined in Part-III of Example 1. Ability of the ground plant meal
and ability of the individual protein fractions (or a mixture of
individual protein fractions) to disperse PMDI in water was tested
using procedures described in Part-II of Example 1.
Gravimetric Solids Analysis:
[0328] After washing and supernatant decanting (3 cycles per the
protocol in Procedure F of Example 1), the resulting slurry of
water-insoluble/water-dispersible components (ca. 35% oven dried
solids by weight) was gravimetrically adjusted to achieve a
dispersion containing approximately 26% by weight solids (by adding
water as necessary). The overall yield of
water-insoluble/water-dispersible components was determined to be
approximately 55% by weight of the starting meal weight. Thus, the
ground canola meal contained (i) approximately 55% by weight of a
water-insoluble/water-dispersible protein fraction, and (ii)
approximately 45% by weight of a water-soluble fraction.
FTIR Spectroscopic Analysis:
[0329] To further characterize extracts from the ground canola
meal, solid state surface ATR FTIR experiments were performed on
the water-insoluble/water-dispersible protein fraction (this sample
was collected after the third wash cycle and was allowed to dry at
23.degree. C.), and on the water-soluble protein fraction (this
sample was collected from the clear supernatant after the third
wash cycle, and was allowed to dry at 23.degree. C. to yield a
transparent amber solid).
[0330] FIG. 18 shows the solid state FTIR spectra for the
water-insoluble/water-dispersible protein fraction isolated from
canola meal together with the water-soluble protein fraction where
the N--H stretching region has been expanded. This figure shows
that the predominant type of amide in the
water-insoluble/water-dispersible protein fraction is the secondary
main-chain amide as evidenced by the single, highly symmetric N--H
stretch band centered near 3275 cm.sup.-1. Although the
water-soluble protein fraction also contains this type of amide, it
contains a significantly higher amount of amine salts (as evidenced
by absorption over the region spanning from approximately 2670-2750
cm.sup.-1) and primary amides as evidenced by the presence of the
two primary N--H stretching bands at approximately 3200 cm.sup.-1
(symmetric) and at approximately 3330 cm.sup.-1 (asymmetric),
respectively. The spectra also reveal that both fractions contain
the characteristic spectroscopic signatures of proteins, even
though both fractions were isolated from raw meal (raw meal
contains other residual water-soluble and water-insoluble
components such as grain hulls, carbohydrates, sugars, and
oils).
[0331] Further, as shown in FIG. 19, the amide-I carbonyl
absorption band for the water-insoluble/water-dispersible protein
fraction was observed to appear as a predominant component at a
wavenumber of approximately 1634 cm.sup.-1, whereas that of the
water-soluble protein fraction was observed to appear as a
lower-intensity shoulder at approximately 1650 cm.sup.-1. As
discussed elsewhere, this feature distinguishes the
water-insoluble/water-dispersible protein fraction from the
water-soluble protein fraction, not only for isolated protein
fractions from castor proteins and soy proteins, but for
protein-containing fractions that are isolated directly from plant
meals like soy meal and canola meal. Moreover, the amide-II band
for the water-insoluble/water-dispersible protein fraction was
observed to appear as a broad band centered at approximately 1530
cm.sup.-1, whereas that of the water-soluble protein fraction was
observed to appear at approximately 1588 cm.sup.-1 together with a
weak shoulder at approximately 1550 cm.sup.-1.
Analysis of the Capacity of Ground Plant Meal and Isolated Protein
Fractions to Disperse Oil:
[0332] A dispersion of 26% (w/w) ground whole canola meal in water
was mixed with PMDI at a 1:1 w/w ratio of PMDI to canola meal
solids. The canola meal contained (i) approximately 55% by weight
water-insoluble/water-dispersible protein fraction and (ii)
approximately 45% by weight water-soluble protein fraction. The
dispersion of ground whole canola meal formed a stable dispersion,
which remained stable during a 1 hour period of observation with no
visual signs of phase separation.
[0333] An aliquot of 26% by weight solids dispersion of
water-insoluble/water-dispersible protein fraction (obtained from
canola plant meal by washing three times per the protocol described
in Procedure F of Example 1) was blended with PMDI at a w/w ratio
of 1 part PMDI to 1 part of the water-insoluble/water-dispersible
protein fraction (on a w/w PMDI/protein fraction-solids basis).
This resulting mixture formed a stable dispersion, which remained
stable during a 1 hour period of observation with no visible signs
of phase separation.
[0334] The water-soluble protein fraction (obtained by extracting
the canola meal and drying the supernatant after centrifuging) was
dissolved in water to yield a 26% (w/w) solids solution. When PMDI
was added to this solution (at a 1:1 weight ratio of PMDI to
water-soluble protein fraction solid material), the resulting
mixture was unstable, and it phase separated immediately after
mixing.
[0335] The results above illustrate that water-emulsified
PMDI-containing adhesive compositions can be prepared using
water-insoluble/water-dispersible protein fraction obtained from
ground plant meal. In addition, the results above illustrate that
water-emulsified PMDI-containing adhesive can be prepared using
ground plant meal compositions (that contain a sufficient amount of
water-insoluble/water-dispersible protein fraction; it is
understood that the ground plant meal composition also comprises
some water-soluble protein fraction). Although the water-soluble
protein fraction did not facilitate dispersion by itself in these
experiments, the dispersion of PMDI (and other oils) is understood
to be achievable so long as a sufficient amount of
water-insoluble/water-dispersible protein fraction is present in
the adhesive composition (or the ground plant meal used in the
adhesive composition).
[0336] To further illustrate the oil-dispersing ability of mixtures
containing a sufficient amount of water-insoluble/water-dispersible
protein fraction, the oil-dispersing characteristics of a meal
containing a large amount of water-insoluble/water-dispersible
protein fraction was compared to the oil-dispersing characteristics
of a commercially available soy-flour product containing a
relatively small amount of water-insoluble/water-dispersible
protein fraction. The commercially available soy-flour product used
was Prolia PDI-90, which is a de-fatted soy flour obtained from
Cargill).
[0337] As is understood, various commercially available derivatives
from plant meals are themselves solvent-extracted (e.g., soy
flour), which results in the removal of a substantial amount of the
water-insoluble/water-dispersible protein fraction. Such
compositions have not been found to facilitate dispersion of oil,
and, thus, are less desirable for use in making an adhesive. For
example, when PMDI was added to a 26% by weight solids dispersion
of soy flour in water at a 1/1 (w/w) of soy flour/PMDI, the PMDI
was observed to immediately phase separate from the mixture. By
contrast, soy meal was used under similar conditions in Example 1
produced a stable dispersion.
[0338] When soy flour was extracted using procedures discussed
herein, the isolated water-insoluble/water-dispersible protein
fraction was capable of dispersing PMDI in water. However, this
fraction was gravimetrically determined to comprise only
approximately 10% by weight of the starting soy flour mixture.
Thus, the component needed for oil dispersion was present in the
starting soy flour, but its effective concentration was too low for
the soy flour to disperse PMDI in water. FTIR spectra for the
isolated water-insoluble/water-dispersible protein fraction and
water-soluble protein fraction extracted from soy flour are
provided in FIG. 20.
[0339] In contrast to soy flour, the
water-insoluble/water-dispersible protein fraction is a major
component in soy meal (at a level of approximately 50% by weight),
thus rendering the soy meal an effective dispersing agent for PMDI
in water. Upon isolation, the water-insoluble/water-dispersible
protein fraction extracted from both soy meal and soy flour (both
of which were able to facilitate the dispersion of PMDI in water)
were observed to contain similar spectral features as measured by
FTIR. Solid state FTIR of the water-insoluble/water-dispersible
protein fraction obtained from soy flour and soy meal are provided
in FIG. 21.
Example 6
Particle Board Composites Made Using Lignin-Containing Adhesive
Compositions
[0340] Lignin and lignin with epoxy additives were used as
alternatives to PMDI in a protein adhesive composition. Adhesive
compositions (described in Table 4) were prepared for the purpose
of creating particle board composites (compositions are given in
Tables 5 and 6). The epoxy additives in this example were mixed
together to form a 50/50 (w/w) blend of glycidyl end-capped
poly(bisphenol-A-co-epichlorohydrin) (BPA; CAS #25036-25-3; Aldrich
Chemical), and trimethylolpropane triglycidyl ether (TMPGE; CAS
#3454-29-3; Aldrich Chemical). The levels of the ingredients were
controlled for the purpose of delivering a constant level of binder
to the finished composites (total binder level=7.65% on a wet wood
basis).
[0341] The sample with partially exfoliated I-44P clay (TP-11,
Nanomer I-44 P from Nanocor, Inc., Arlington Heights, Ill.) was
prepared by adding a premixed 30/70 w/w amalgam of I-44P in an oil
carrier (where the oil carrier was a 50/50 w/w blend of
Tego-Protect-5000 silicone with (R)-(+)-limonene (Sigma-Aldrich,
Corp)) to form a mixture and subjecting the mixture of conditions
for achieving at least partial exfoliation. Specifically, the
amalgam was prepared based on the following general procedure: a
30/70 mixture (w/w) of Nanomer I-44P/oil carrier was prepared by
mixing 30 grams of I-44P from Nanocor, Inc. into 70 grams of oil
carrier to form a mixture. Then, the mixture was mixed using a
laboratory mixer and a dispersion-mixing blade. Next, the mixture
was mixed under high shear conditions, then covered and placed in
an ultrasonic bath to facilitate further exfoliation. Partial
exfoliation of the clay in the oil carrier was evidenced by the
formation of a gel-like amalgam.
[0342] In addition, the combined levels of lignin and epoxy were
proportionally reduced to account for the presence of the clay
(this was done to maintain a constant overall binder level). Thus,
in the case where clay was added to the binder, the total organic
content of the binder was lower than that of the comparable control
sample (TP-10).
[0343] Particle board composites were made according to the
following procedure. 100 g of wet adhesive was slowly added to 600
g of wood particulate and the composition was mixed with a
mechanical mixer. A 9-inch.times.9-inch.times.9-inch wood forming
box was centered on a 12''.times.12''.times.1/8'' stainless steel
plate, which was covered with aluminum foil. The treated-wood was
added slowly into the forming box to try to get a uniform density
of adhesive-coated wood particles. After all the treated-wood was
added, the composition was compressed by hand with a
87/8''.times.87/8''.times.1/4'' plywood board, and the forming box
was carefully removed so that the treated particle board matte
would not be disturbed. The board was removed from the top of the
matte and a piece of aluminum foil was placed on top together with
another 12''.times.12''.times.1/8'' stainless steel plate. The
particleboard matte was pressed and cured to a thickness of 3/4''
using the following conditions: 117 psi pressure for 10 minutes at
a press platen temperature of 205.degree. C. The composites were
cut into 6 inch by 4 inch samples. Qualitative observations are
provided in Table 7, and the pressed composites are shown in FIG.
22.
[0344] Particle board composites made with lignin alone or with
protein alone cohesively disintegrated upon being removed from the
press (TP-12 and TP-13). Surprisingly however, composites made with
combinations of protein and lignin were observed to remain
cohesively intact. Thus, the combination of plant meal and lignin
led to an unexpected and surprising response that neither component
was able to provide on its own. Namely, when used in combination, a
protein meal and lignin can be used to formulate adhesive binders
to produce densified wood composites that remain cohesively intact
after pressing.
TABLE-US-00004 TABLE 4 WET ADHESIVE COMPOSITIONS* Description:
Canola Protein Meal; Other Weight Percent of Components in Wet
Adhesive Composition Sample Additives Canola BPA TMPGP Nanocor
Carrier No. & Oil Carrier Water Meal Urea Lignin epoxy epoxy
I-44P Oil TP-9 protein + lignin 55.28 20.45 0.90 23.37 0 0 0 0
TP-10 protein + 50/50 w/w 55.28 20.45 0.90 11.69 5.84 5.84 0 0
lignin/epoxy TP-11 protein + 50/50 w/w 55.28 20.45 0.90 10.23 5.11
5.11 0.88 2.04 lignin/epoxy with 70/30 w/w I44P/(50/50 w/w
Tego/limonene) TP-12 lignin only 72.60 0 0.55 26.85 0 0 0 0 TP-13
protein meal only 71.59 27.84 0.57 0 0 0 0 0 *Expressed as percent
by weight.
TABLE-US-00005 TABLE 5 AMOUNT OF WET ADHESIVES FROM TABLE 4 ADDED
TO 600 GRAMS OF WOOD FOR PREPARING PARTICLE BOARD COMPOSITES Weight
Weight Components in the Adhesive of wet Sample Composition: Canola
Protein Meal; wood adhesive No. Other Additives & Oil Carrier
grams grams TP-9 protein + lignin 600 111.21 TP-10 protein + 50/50
w/w lignin/epoxy 600 111.21 TP-11 protein + 50/50 w/w lignin/epoxy
600 111.22 with 70/30 w/w I44P/ (50/50 w/w Tego/limonene) TP-12
lignin only 600 181.48 TP-13 protein only 600 175.03 * Composites
had a constant binder level of 7.65% by weight.
TABLE-US-00006 TABLE 6 DRY/CURED PARTICLE BOARD COMPOSITIONS USING
THE WET ADHESIVES DESCRIBED IN TABLE 4 Description of the Adhesive
(Canola Protein Meal, Weight Percent of Components in Dry/Cured
Particle Board Composition Sample Other Additives, Canola BPA TMPGE
Nanocor Carrier No. & Oil Carrier) Wood Meal Urea Lignin epoxy
epoxy I-44P Oil TP-9 protein + lignin 92.35 3.50 0.15 4.00 0 0 0 0
TP-10 protein + 50/50 w/w 92.35 3.50 0.15 2.00 1.00 1.00 0 0
lignin/epoxy TP-11 protein + 50/50 w/w 92.35 3.50 0.15 1.75 0.875
0.875 0.15 0.35 lignin/epoxy with 70/30 w/w I44P/(50/50 w/w
Tego/limonene) TP-12 lignin only 92.35 0 0.15 7.50 0 0 0 0 TP-13
protein only 92.35 7.50 0.15 0 0 0 0 0 * Composites had a constant
binder level of 7.65% by weight. Amount of components in the
adhesive composition are presented in percent by weight of the
adhesive composition.
TABLE-US-00007 TABLE 7 OBSERVATIONS OF THE WET ADHESIVE AND
PARTICLE BOARD COMPOSITES MADE THEREFROM Sample No. Mixing
Observations Board Quality TP-9 The formulation mixed well The
board was a tough using a mechanical mixer. solid composite having
The resulting mixture a measured was a viscous, tar-like liquid.
density of 0.57 g/cm.sup.3 (35.86 lb/ft.sup.3) TP-10 The
formulation mixed easily The board was a tough with a mechanical
solid composite mixer. The resulting mixture having a measured was
a low to moderate- density of 0.56 g/cm.sup.3 viscosity pourable
liquid. (34.99 lb/ft.sup.3) TP-11 The formulation mixed easily The
board was a tough with a mechanical mixer. solid composite The
resulting mixture was a having a measured moderate-viscosity
pourable density of 0.55 g/cm.sup.3 liquid. (34.64 lb/ft.sup.3)
TP-12 The formulation mixed easily The surfaces stayed with a
mechanical mixer. together but the center The resulting mixture was
a of the board was low to moderate-viscosity delaminated. pourable
liquid. The center portion of the board consisted of very loose
wood particles (cohesive failure). TP-13 The formulation mixed
easily The surfaces stayed with a mechanical together but mixer.
The the center of the resulting mixture was a low board was
delaminated. to moderate-viscosity pourable The center portion
liquid. of the board consisted of very loose wood particles
(cohesive failure).
Example 7
Particle Board Composites Made Using Phenol-Formaldehyde-Containing
2-Part Adhesive Compositions
[0345] Phenol-Formaldehyde (PF) resin (Woodweld.TM. GP190080 from
Georgia Pacific) was used together with urea (from Sigma-Aldrich),
PMDI (Mondur.TM. 541 from Bayer) and ground canola meal (20-70
micrometers, obtained from Columbia Innovations, a division of
Columbia Forest Products, Inc.) to create a series of 2-part
adhesive compositions. The "Part-B" components of the 2-part
adhesive were first premixed (i.e., water, canola meal, PF, and
urea), and were then combined with the "Part-A" component (PMDI) to
yield the wet adhesive compositions as described in Table 1. These
adhesives were then used to make particle board composites
(compositions are given in Tables 2 and 3).
[0346] Particle board composites were made according to the
following procedure. The appropriate aliquot of wet adhesive (Table
2) was slowly added by means of spraying the mixture into a 4-foot
diameter rotary tumbler containing 12.315 kilograms of wood furnish
particulate (western pine, wood moisture content=8.5% by weight)
over a period of approximately 1 to 2 minutes using a pneumatic
sprayer (The Professional Hopper Gun C.M.T..TM. equipped with a
5/16 in. brass air nozzle using 38-40 psi of compressed air). The
treated wood was allowed to tumble for approximately 5-10 minutes
before being removed. Approximately 3,837 g of treated-wood furnish
was added into a forming box to achieve a uniform distribution of
the adhesive-coated wood particles (this was the weight needed to
achieve a 2'.times.2' board with a target thickness of 5/8'' and
with a target density of ca. 45 pounds per cubic foot). The
pre-form was inserted into a press (a 36''.times.36'' hydraulic
press), and the internal gas pressure and temperature were
monitored using a Pressman.TM. monitoring system with platen
set-temperatures=330.degree. F. for a dwell time of approximately 3
minutes and 40 seconds (the platens were protected with
silicone-coated release paper, and the total cycle time was
approximately 4.5 to 5 minutes). The densities of the finished
composites were measured, and multiple sample specimens were cut
from the boards for the purpose of measuring physical properties
(e.g., modulus of rupture (MOR) and modulus of elasticity (MOE)).
Physical property data are provided in Table 4.
TABLE-US-00008 TABLE 1 WET ADHESIVE COMPOSITIONS* Weight Percent of
Components in Wet Adhesive Composition Sample Materials Combined
with Canola No. Canola Meal and Ratios Water Meal Urea PF Resin
PMDI TP23-10 (PMDI + PF)/Meal = 1.68/1; 58.56 14.64 2.19 4.10 20.51
PF/PMDI = 1/5; pH neutral TP23-2 (PMDI + PF)/Meal = 1.68/1; 64.71
17.20 1.74 8.17 8.17 PF/PMDI = 1/1; pH neutral TP23-3 (PMDI +
PF)/Meal = 0.95/1; 58.11 20.42 2.07 0.00 19.40 PF/PMDI = 0; pH
neutral TP23-4 (PMDI + PF)/Meal = 1.4/1; 59.61 15.84 2.37 2.22
19.96 PF/PMDI = 1/9; pH neutral TP23-5 (PMDI + PF)/Meal = 1.4/1;
61.07 15.27 2.28 4.28 17.10 PF/PMDI = 1/4; pH neutral *Expressed as
percent by weight after mixing Parts A + B.
TABLE-US-00009 TABLE 2 AMOUNT OF WET ADHESIVES FROM TABLE 1 ADDED
TO 12.315 KILOGRAMS OF WOOD FURNISH FOR PREPARING PARTICLE BOARD
COMPOSITES Weight of Weight Wet Sample Materials Combined with
Canola Wood Adhesive No. Meal and Ratios (kilograms) (grams)
TP23-10 (PMDI + PF)/Meal = 1.68/1; 12.315 929.01 PF/PMDI = 1/5; pH
neutral TP23-2 (PMDI + PF)/Meal = 1.68/1; 12.315 1,168.21 PF/PMDI =
1/1; pH neutral TP23-3 (PMDI + PF)/Meal = 0.95/1; 12.315 984.18
PF/PMDI = 0; pH neutral TP23-4 (PMDI + PF)/Meal = 1.4/1; 12.315
856.13 PF/PMDI = 1/9; pH neutral TP23-5 (PMDI + PF)/Meal = 1.4/1;
12.315 888.43 PF/PMDI = 1/4; pH neutral
TABLE-US-00010 TABLE 3 DRY/CURED PARTICLE BOARD COMPOSITIONS USING
THE WET ADHESIVES DESCRIBED IN TABLE 1 (OVEN-DRY WEIGHT BASIS)
Weight Percent of Components in Dry/Cured Particle Board
Composition Sample Materials Combined with Canola No. Canola Meal
and Ratios Wood Meal Urea PF Resin PMDI Binder* TP23-10 (PMDI +
PF)/Meal = 1.68/1; 96.97 1.07 0.16 0.30 1.50 3.03 PF/PMDI = 1/5; pH
neutral TP23-2 (PMDI + PF)/Meal = 1.68/1; 96.76 1.58 0.16 0.75 0.75
3.24 PF/PMDI = 1/1; pH neutral TP23-3 (PMDI + PF)/Meal = 0.95/1;
96.76 1.58 0.16 0.00 1.50 3.24 PF/PMDI = 0; pH neutral TP23-4 (PMDI
+ PF)/Meal = 1.4/1; 97.27 1.07 0.16 0.15 1.35 2.73 PF/PMDI = 1/9;
pH neutral TP23-5 (PMDI + PF)/Meal = 1.4/1; 97.27 1.07 0.16 0.30
1.20 2.73 PF/PMDI = 1/4; pH neutral *Weight percent binder is the
sum of the weight percent of canola meal, urea, PF resin, and
PMDI
TABLE-US-00011 TABLE 4 PHYSICAL PROPERTIES OF COMPOSITES (AVERAGES
AND STANDARD DEVIATIONS FROM MULTIPLE SPECIMENS SAMPLED FROM 2 TO 3
BOARDS PER SAMPLE-TYPE) Number Number Weight Sample Density (lbs.
Flex Modulus Modulus of of of Percent No. per cubic ft.) (psi)
Rupture (psi) Samples Boards Binder TP23-10 44.3 .+-. 1.3 290,000
.+-. 30,000 1410 .+-. 220 12 3 3.03% TP23-2 42.4 .+-. 1.5 215,000
.+-. 30,000 840 .+-. 130 8 2 3.24% TP23-3 44.7 .+-. 1 290,000 .+-.
19,000 1400 .+-. 100 12 3 3.24% TP23-4 44.1 .+-. 1 273,000 .+-.
14,000 1300 .+-. 120 12 3 2.73% TP23-5 46.6 .+-. 1.1 319,000 .+-.
25,000 1490 .+-. 120 8 2 2.73%
[0347] Experimental results (e.g., the data in Table 4) demonstrate
that the composite boards had good mechanical stability. A
comparison of physical property data from Sample Nos. TP23-10,
TP23-2, and TP23-3 indicates that PF can be included in the plant
meal/PMDI based adhesives up to a certain amount without adversely
affecting the strength of the composite. For example, the composite
Sample No. TP23-3 (which did not contain PF) had a Modulus of
Rupture of 1400.+-.100 PSI and composite Sample No. TP23-10 (which
contained PF) had a Modulus of Rupture of 1410+/-220 PSI, but the
Modulus of Rupture was less for composite Sample No. TP23-2 (which
contained more PF than Sample Nos. TP23-10 and TP23-3).
[0348] Another observation from the data in Table 4 is that the
amount of adhesive required to form a wood composite may be reduced
when using a plant meal/PMDI based adhesive that contains PF. For
example, composite Sample No. TP23-5 had the highest Modulus of
Rupture of the samples prepared, even though it contained only 2.73
percent by weight binder.
[0349] It is understood that adhesives of the type described in
this example can be prepared in various ways. For instance, instead
of pre-dispersing or dissolving the PF in the Part-B dispersion
(i.e., instead of premixing the PF with canola meal, water, and
urea), dry PF powder can be mixed with the wood furnish prior to
the applying the rest of the mixed wet adhesive components to the
wood.
[0350] It is contemplated that adhesives described in this example
can be used to prepare other types of wood composites such as, for
example, oriented strand board and medium-density fiberboard.
INCORPORATION BY REFERENCE
[0351] The entire disclosure of each of the patent and scientific
documents referred to herein is incorporated by reference for all
purposes.
EQUIVALENTS
[0352] The invention may be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The foregoing embodiments are therefore to be considered
in all respects illustrative rather than limiting on the invention
described herein. Scope of the invention is thus indicated by the
appended claims rather than by the foregoing description, and all
changes that come within the meaning and range of equivalency of
the claims are intended to be embraced therein.
* * * * *