U.S. patent application number 13/584651 was filed with the patent office on 2013-08-22 for binder compositions comprising lignin derivatives.
The applicant listed for this patent is Alex BERLIN. Invention is credited to Alex BERLIN.
Application Number | 20130213550 13/584651 |
Document ID | / |
Family ID | 44367089 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130213550 |
Kind Code |
A1 |
BERLIN; Alex |
August 22, 2013 |
BINDER COMPOSITIONS COMPRISING LIGNIN DERIVATIVES
Abstract
The present disclosure provides an adhesive composition
comprising derivatives of native lignin and an isocyanate-based
binder such as methylene diphenyl diisocyanate. The present
compositions may further comprise formaldehyde-based resins such as
PF, UF, and MF. While not wishing to be bound by theory, it is
believed that incorporating derivatives of native lignin in
isocyanate compositions will reduce incidence of pre-curing.
Inventors: |
BERLIN; Alex; (Davis,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BERLIN; Alex |
Davis |
CA |
US |
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|
Family ID: |
44367089 |
Appl. No.: |
13/584651 |
Filed: |
August 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/CA2011/000182 |
Feb 15, 2011 |
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13584651 |
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61304745 |
Feb 15, 2010 |
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61304742 |
Feb 15, 2010 |
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Current U.S.
Class: |
156/62.2 ;
252/182.29; 525/480 |
Current CPC
Class: |
B29C 70/34 20130101;
C08G 18/4081 20130101; B29K 2311/14 20130101; C08L 97/005 20130101;
C09J 175/04 20130101; B27N 3/04 20130101; B29K 2105/12 20130101;
C08L 97/00 20130101; C09J 197/005 20130101; B29K 2075/00 20130101;
C08G 18/7671 20130101; B29C 70/12 20130101; C09J 161/06 20130101;
D21J 1/04 20130101; C08L 61/06 20130101; C09J 197/005 20130101;
C08L 61/06 20130101; C08L 97/00 20130101; C08L 61/06 20130101; C08L
97/005 20130101; C09J 161/06 20130101; C08L 97/00 20130101; C09J
161/06 20130101; C08L 97/005 20130101 |
Class at
Publication: |
156/62.2 ;
525/480; 252/182.29 |
International
Class: |
C09J 197/00 20060101
C09J197/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2010 |
CA |
PCT/CA2010/000800 |
Claims
1. An adhesive system comprising: a. a resin comprising at least
about 30% by weight of phenol-formaldehyde resin and at least about
30% by weight of derivative of native lignin; and b. an
isocyanate-based binder.
2. A composition according to claim 1 wherein the composition
comprises at least about 35% by weight of derivative of native
lignin.
3. A composition according to claim 1 wherein the derivative of
native lignin has an ethoxy content of 0.45 mmol/g or greater.
4. A composition according to claim 1 wherein the isocyanate-based
binder comprises methylene diphenyl diisocyanate.
5. A composition according to claim 1 wherein the isocyanate-based
binder comprises methylene diphenyl diisocyanate and a derivative
of native lignin.
6. A composition according to claim 1 wherein the isocyanate-based
binder comprises methylene diphenyl diisocyanate and a derivative
of native lignin wherein the derivative of native lignin has an
aliphatic hydroxyl content of from about 0.6 mmol/g to about 6.5
mmol/g.
7. Use of the system according to claim 1 for the production of a
fibreboard.
8. Use of the system according to claim 1 as an adhesive for low
density fibreboard (LDF), medium density fibreboard (MDF), high
density fibreboard (HDF), strawboard & other agricultural
fibre/particle boards, oriented strand board (OSB), particle board,
wood fibre insulation board (WFIB), or polyurethane foams.
9. A method of producing a fibreboard a) providing fibres to a
blowline; b) providing an adhesive system according to claim 1; c)
treating the fibres with the adhesive; d) preferably at least
partially drying the treated fibres; and e) pressing the treated
fibres to form a fibreboard.
10. A binder composition comprising methylene diphenyl diisocyanate
and a derivative of native lignin.
11. A composition according to claim 10 wherein the derivative of
native lignin has an aliphatic hydroxyl content of from about 0.1
mmol/g to about 8 mmol/g.
12. A composition according to claim 10 wherein the derivative of
native lignin has an aliphatic hydroxyl content of from about 0.6
mmol/g to about 6.5 mmol/g
13. A composition according to claim 10 comprising from about 0.1%
to about 25%, by weight, of the derivative of native lignin.
14. A composition according to claim 10 comprising from about 50%
to about 99%, by weight, of methylene diphenyl diisocyanate.
15. A method of producing a composition according to claim 10, said
method comprising: a) providing a composition comprising
derivatives of native lignin in a suitable solvent; b) providing a
resin composition comprising methylene diphenyl diisocyanate; c)
mixing the compositions; and d) removing the solvent.
16. A fibreboard comprising a composition according to claim
10.
17. Use of a composition according to claim 10 as a binder for low
density fibreboard (LDF), medium density fibreboard (MDF), high
density fibreboard (HDF), strawboard & other agricultural
fibre/particle boards, oriented strand board (OSB), particle board,
wood fibre insulation board (WFIB), or polyurethane foams.
18. A method of producing a fibreboard f) providing fibres to a
blowline; g) providing a binder comprising methylene diphenyl
diisocyanate and a derivative of native lignin; h) treating the
fibres with the binder; i) preferably at least partially drying the
treated fibres; and j) pressing the treated fibres to form a
fibreboard.
Description
[0001] This application is a continuation of PCT/CA2011/000182,
filed Feb. 15, 2011; which claims the priority of U.S. Provisional
Application No. 61/304,745, filed Feb. 15, 2010; U.S. Provisional
Application No. 61/304,742, filed Feb. 15, 2010; and
PCT/CA2010/000800, filed May 27, 2010. The contents of the
above-identified applications are incorporated herein by reference
in their entirety.
TECHNICAL FIELD
[0002] This disclosure relates to derivatives of native lignin
recovered from lignocellulosic feedstocks, and industrial
applications thereof. More particularly, this disclosure relates to
compositions, uses, processes and methods utilizing derivatives of
native lignin.
BACKGROUND
[0003] Native lignin is a naturally occurring amorphous complex
cross-linked organic macromolecule that comprises an integral
component of all plant biomass. The chemical structure of lignin is
irregular in the sense that different structural units (e.g.,
phenylpropane units) are not linked to each other in any systematic
order. It is known that native lignin comprises pluralities of two
monolignol monomers that are methoxylated to various degrees
(trans-coniferyl alcohol and trans-sinapyl alcohol) and a third
non-methoxylated monolignol (trans-p-coumaryl alcohol). Various
combinations of these monolignols comprise three building blocks of
phenylpropanoid structures i.e. guaiacyl monolignol, syringyl
monolignol and p-hydroxyphenyl monolignol, respectively, that are
polymerized via specific linkages to form the native lignin
macromolecule.
[0004] Extracting native lignin from lignocellulosic biomass during
pulping generally results in lignin fragmentation into numerous
mixtures of irregular components. Furthermore, the lignin fragments
may react with any chemicals employed in the pulping process.
Consequently, the generated lignin fractions can be referred to as
lignin derivatives and/or technical lignins. As it is difficult to
elucidate and characterize such complex mixture of molecules,
lignin derivatives are usually described in terms of the
lignocellulosic plant material used, and the methods by which they
are generated and recovered from lignocellulosic plant material,
i.e. hardwood lignins, softwood lignins, and annual fibre
lignins.
[0005] Native lignins are partially depolymerized during the
pulping processes into lignin fragments which are soluble in the
pulping liquors and subsequently separated from the cellulosic
pulps. Post-pulping liquors containing lignin and polysaccharide
fragments, and other extractives, are commonly referred to as
"black liquors" or "spent liquors", depending on the pulping
process. Such liquors are generally considered a by-product, and it
is common practice to combust them to recover some energy value in
addition to recovering the cooking chemicals. However, it is also
possible to precipitate and/or recover lignin derivatives from
these liquors. Each type of pulping process used to separate
cellulosic pulps from other lignocellulosic components produces
lignin derivatives that are very different in their
physico-chemical, biochemical, and structural properties.
[0006] Given that lignin derivatives are available from renewable
biomass sources there is an interest in using these derivatives in
certain industrial processes. For example, U.S. Pat. No. 5,173,527
proposes using lignin-cellulosic materials in phenol-formaldehyde
resins. A. Gregorova et al.
[0007] propose using lignin in polypropylene for it radical
scavenging properties (A. Gregorova et al., Radical scavenging
capacity of lignin and its effect on processing stabilization of
virgin and recycled polypropylene, Journal of Applied Polymer
Science 106-3 (2007) pp. 1626-1631).
[0008] However, large-scale commercial application of the extracted
lignin derivatives, particularly those isolated in traditional
pulping processes employed in the manufacture of pulp and paper,
has been limited due to, for example, the inconsistency of their
chemical and functional properties. This inconsistency may, for
example, be due to changes in feedstock supplies and the particular
extraction/generation/recovery conditions. These issues are further
complicated by the complexity of the molecular structures of lignin
derivatives produced by the various extraction methods and the
difficulty in performing reliable routine analyses of the
structural conformity and integrity of recovered lignin
derivatives. Nevertheless efforts continue to use lignin
derivatives on a commercial scale.
[0009] For many years fibreboard products have been manufactured
from wood or agricultural substrates using various adhesives.
Formaldehyde-based resins such as phenol formaldehyde (PF), urea
formaldehyde (UF) and melamine formaldehyde (MF) are extremely
common and used for a variety of purposes such as manufacturing of
housing and furniture panels such as medium density fibreboard
(MDF), oriented strand board (OSB), plywood, and particleboard.
Concerns about the toxicity of formaldehyde have led regulatory
authorities to mandate the reduction of formaldehyde emissions
(e.g. California Environmental Protection Agency Airborne Toxic
Control Measure (ATCM) to Reduce Formaldehyde Emissions from
Composite Wood Products, Apr. 26, 2007). There have been attempts
to add lignin derivatives to formaldehyde-based resins. However,
such attempts have not been entirely successful. For example, past
attempts at adding Alcell.RTM. lignin to PF resins have been
largely unsuccessful due to the relatively poor performance
characteristics of the final product where the normalized
Alcell.RTM. lignin-PF resin bond strength at 150.degree. C. was
3,079 MPa*cm.sup.2/g as tested by the ABES method (Wescott, J. M.,
Birkeland, M. J., Traska, A. E., New Method for Rapid Testing of
Bond Strength for Wood Adhesives, Heartland Resource Technologies
Waunakee, Wis., U.S.A. and Frihart, C. R. and Dally, B. N., USDA
Forest Service, Forest Products Laboratory, Madison, Wis., U.S.A.,
Proceedings 30.sup.th Annual Meeting of The Adhesion Society, Inc.,
Feb. 18-21, 2007, Tampa Bay, Fla., USA). These values are
significantly lower than the current commercial adhesives. For
instance, plywood or OSB made with PF resins are expected to have a
bond strength in the region of 3,200-3,600 MPa*cm.sup.2/g.
Furthermore, lignin-containing PF-resins often do not cure quickly
enough or completely enough under normal production conditions for
fibreboard. This lack of cure-speed and lack of bond strength has
limited the amount of lignin derivative that has been included in
the formaldehyde-resins to relatively low levels.
[0010] An adhesive should meet certain criteria in order to be
acceptable for industrial use. For example, the adhesive will
preferably be available in a stable form such as a spray-dried
powder or stable liquid. The adhesive will preferably set quickly
enough to enable its use as a core adhesive for thick multi-layer
panels but should not suffer from excessive "pre-cure".
[0011] Methylene diphenyl diisocyanate (MDI) is a widely used
diisocyanate commonly used in the manufacture of polyurethanes and
as an adhesive. MDI has the advantage that it is highly reactive
and has strong bondability as well as being formaldehyde free. MDI
polymerizes in the presence of water which reduce the ecological
risks associated with its use.
[0012] It is known to use isocyanate-based binders such as MDI for
fibreboard (see, for example, U.S. Pat. No. 6,692,670) but they
have not, to date, been widely adopted for various reasons such as
cost, cure-rate, and the need for release-agents to avoid the board
sticking to the press-plates.
[0013] A significant issue with the use of MDI is its high
sensitivity to moisture and temperature. In many manufacturing
processes MDI suffers from significant premature polymerization
(pre-cure) leading to substantial loss of resin efficiency and,
hence, higher resin consumption. It is estimated that as much as
10% of the MDI may be lost to pre-curing leading to increased costs
and decreased process efficiency.
SUMMARY
[0014] The present disclosure provides an adhesive composition
comprising derivatives of native lignin and an isocyanate-based
binder such as methylene diphenyl diisocyanate. The present
compositions may further comprise formaldehyde-based resins such as
PF, UF, and MF. While not wishing to be bound by theory, it is
believed that incorporating derivatives of native lignin in
isocyanate compositions will reduce incidence of pre-curing.
[0015] As used herein, the terms "methylene diphenyl diisocyanate"
and "MDI" encompass oligomers of methylene diphenyl diisocyanate
sometimes referred to as "pMDI" or "polymethylene polyphenylene
polyisocyanate"
[0016] As used herein, the term "native lignin" refers to lignin in
its natural state, in plant material.
[0017] As used herein, the terms "lignin derivatives" and
"derivatives of native lignin" refer to lignin material extracted
from lignocellulosic biomass. Usually, such material will be a
mixture of chemical compounds that are generated during the
extraction process.
[0018] This summary does not necessarily describe all features of
the invention. Other aspects, features and advantages of the
invention will be apparent to those of ordinary skill in the art
upon review of the following description of specific embodiments of
the invention.
DETAILED DESCRIPTION
[0019] The present disclosure provides compositions comprising
isocyanate-based binder such as methylene diphenyl diisocyanate
(MDI) and derivatives of native lignin. MDI compositions comprising
lignin derivatives suffer from a lower incidence of pre-cure. While
not wishing to be bound by theory, lignin derivatives may reduce
the sensitivity of MDI to moisture and temperature, the latter
being factors responsible for early MDI polymerization ("precure").
The incorporation of lignin in MDI can be problematic due to the
instability and irregularity of the resulting lignin-containing MDI
resins. The present compositions may comprise formaldehyde-based
resins comprising lignin derivatives such as lignin-phenol
formaldehyde (LPF). It is believed that the presence of
isocyanate-based binder improves the cure-speed of the LPF making
it more suitable for industrial applications such as an adhesive
for the core of a multi-layer fibreboard. It is further believed
that the presence of isocyanate-based binder allows increased
amounts of the formaldehyde-based resin to be substituted with
lignin derivative. For example, the present compositions may
comprise 30% or more, 35% or more, 40% or more, by weight of lignin
derivative.
[0020] Any suitable isocyanate-based binder. For example, polymeric
MDI (polymethylene polyphenylene polyisocyanate) such as
emulsifiable, polymeric MDI' s may be used. Examples of
commercially available polymeric MDI include I-Bond.RTM. and
Rubinate.RTM. such as Rubinate 1840 isocyanate, Rubinate M
isocyanate, Rubinate 1780 isocyante, available from Huntsman
Polyurethanes located in West Deptford, N.J. The MDI preferably has
a diisocyanate content of about 50% or less, about 48% or less,
about 45% or less, about 40% or less, by weight.
[0021] The polymeric MDI may also contain urethane modifications,
isocyanurate modifications, biurets, ureas, etc. The polymeric MDI
may be modified to be water dispersible, and applied in an aqueous
emulsion form. Such a method for modifying the polymeric MDI to be
water dispersible is fully disclosed in the above-identified U.S.
Pat. No. 3,996,154.
[0022] The polymeric MDI may be used alone, or in conjunction with
other binder materials, including, but not limited to, formaldehyde
containing binder materials, diluents, extenders, fillers, etc.
Suitable extenders include, for example, oils, such as soy oil and
linseed oil, solvents, lignin, carbohydrates, etc. Suitable fillers
include, for example, fibreglass, plastics, waste materials, etc.
Moreover, the polymeric MDI may also include fire retardants, such
as, for example, ammonium polyphosphates, trichloropropyl phosphate
(TCPP), melamine, triphenyl phosphate, etc. Furthermore, the
polymeric MDI may also include suitable release agents, such as,
for example, soaps, fatty acids, waxes, silicones, fatty acid
salts, etc.
[0023] Additionally, the polymeric MDI may also include biocides,
such as boric acid, etc.
[0024] The present disclosure provides derivatives of native lignin
recovered during or after pulping of lignocellulosic feedstocks.
The pulp may be from any suitable lignocellulosic feedstock
including hardwoods, softwoods, annual fibres, and combinations
thereof. Hardwood feedstocks include Acacia; Afzelia; Synsepalum
duloificum; Albizia; Alder (e.g. Alnus glutinosa, Alnus rubra);
Applewood; Arbutus; Ash (e.g. F. nigra, F. quadrangulata, F.
excelsior, F. pennsylvanica lanceolata, F. latifolia, F. profunda,
F. americana); Aspen (e.g. P. grandidentata, P. tremula, P.
tremuloides); Australian Red Cedar (Toona ciliata); Ayna
(Distemonanthus benthamianus); Balsa (Ochroma pyramidale); Basswood
(e.g. T. americana, T. heterophylla); Beech (e.g. F. sylvatica, F.
grandifolia); Birch; (e.g. Betula populifolia, B. nigra, B.
papyrifera, B. lenta, B. alleghaniensis/B. lutea, B. pendula, B.
pubescens); Blackbean; Blackwood; Bocote; Boxelder; Boxwood;
Brazilwood; Bubinga; Buckeye (e.g. Aesculus hippocastanum, Aesculus
glabra, Aesculus flava/Aesculus octandra); Butternut; Catalpa;
Cherry (e.g. Prunus serotina, Prunus pennsylvanica, Prunus avium);
Crabwood; Chestnut; Coachwood; Cocobolo; Corkwood; Cottonwood (e.g.
nPopulus balsamifera, Populus deltoides, Populus sargentii, Populus
heterophylla); Cucumbertree; Dogwood (e.g. Cornus florida, Cornus
nuttallii); Ebony (e.g. Diospyros kurzii, Diospyros melanida,
Diospyros crassiflora); Elm (e.g. Ulmus americana, Ulmus procera,
Ulmus thomasii, Ulmus rubra, Ulmus glabra); Eucalyptus; Greenheart;
Grenadilla; Gum (e.g. Nyssa sylvatica, Eucalyptus globulus,
Liquidambar styraciflua, Nyssa aquatica); Hickory (e.g. Carya alba,
Carya glabra, Carya ovata, Carya laciniosa); Hornbeam; Hophornbeam;
Ipe; Iroko; Ironwood (e.g. Bangkirai, Carpinus caroliniana,
Casuarina equisetifolia, Choricbangarpia subargentea, Copaifera
spp., Eusideroxylon zwageri, Guajacum officinale, Guajacum sanctum,
Hopea odorata, Ipe, Krugiodendron ferreum, Lyonothamnus lyonii (L.
floribundus), Mesua ferrea, Olea spp., Olneya tesota, Ostrya
virginiana, Parrotia persica, Tabebuia serratifolia); Jacaranda;
Jotoba; Lacewood; Laurel; Limba; Lignum vitae; Locust (e.g. Robinia
pseudacacia, Gleditsia triacanthos); Mahogany; Maple (e.g. Acer
saccharum, Acer nigrum, Acer negundo, Acer rubrum, Acer
saccharinum, Acer pseudoplatanus); Meranti; Mpingo; Oak (e.g.
Quercus macrocarpa, Quercus alba, Quercus stellata, Quercus
bicolor, Quercus virginiana, Quercus michauxii, Quercus prinus,
Quercus muhlenbergii, Quercus chrysolepis, Quercus lyrata, Quercus
robur, Quercus petraea, Quercus rubra, Quercus velutina, Quercus
laurifolia, Quercus falcata, Quercus nigra, Quercus phellos,
Quercus texana); Obeche; Okoume; Oregon Myrtle; California Bay
Laurel; Pear; Poplar (e.g. P. balsamifera, P. nigra, Hybrid Poplar
(Populus.times.canadensis)); Ramin; Red cedar; Rosewood; Sal;
Sandalwood; Sassafras; Satinwood; Silky Oak; Silver Wattle;
Snakewood; Sourwood; Spanish cedar; American sycamore; Teak; Walnut
(e.g. Juglans nigra, Juglans regia); Willow (e.g. Salix nigra,
Salix alba); Yellow poplar (Liriodendron tulipifera); Bamboo;
Palmwood; and combinations/hybrids thereof.
[0025] For example, hardwood feedstocks for the present disclosure
may be selected from Acacia, Aspen, Beech, Eucalyptus, Maple,
Birch, Gum, Oak, Poplar, and combinations/hybrids thereof. The
hardwood feedstocks for the present disclosure may be selected from
Populus spp. (e.g. Populus tremuloides), Eucalyptus spp. (e.g.
Eucalyptus globulus), Acacia spp. (e.g. Acacia dealbata), and
combinations/hybrids thereof.
[0026] Softwood feedstocks include Araucaria (e.g. A. cunninghamii,
A. angustifolia, A. araucana); softwood Cedar (e.g. Juniperus
virginiana, Thuja plicata, Thuja occidentalis, Chamaecyparis
thyoides Callitropsis nootkatensis); Cypress (e.g. Chamaecyparis,
Cupressus Taxodium, Cupressus arizonica, Taxodium distichum,
Chamaecyparis obtusa, Chamaecyparis lawsoniana, Cupressus
semperviren); Rocky Mountain Douglas fir; European Yew; Fir (e.g.
Abies balsamea, Abies alba, Abies procera, Abies amabilis); Hemlock
(e.g. Tsuga canadensis, Tsuga mertensiana, Tsuga heterophylla);
Kauri; Kaya; Larch (e.g. Larix decidua, Larix kaempferi, Larix
laricina, Larix occidentalis); Pine (e.g. Pinus nigra, Pinus
banksiana, Pinus contorta, Pinus radiata, Pinus ponderosa, Pinus
resinosa, Pinus sylvestris, Pinus strobus, Pinus monticola, Pinus
lambertiana, Pinus taeda, Pinus palustris, Pinus rigida, Pinus
echinata); Redwood; Rimu; Spruce (e.g. Picea abies, Picea mariana,
Picea rubens, Picea sitchensis, Picea glauca); Sugi; and
combinations/hybrids thereof.
[0027] For example, softwood feedstocks which may be used herein
include cedar; fir; pine; spruce; and combinations thereof. The
softwood feedstocks for the present disclosure may be selected from
loblolly pine (Pinus taeda), radiata pine, jack pine, spruce (e.g.,
white, interior, black), Douglas fir, Pinus silvestris, Picea
abies, and combinations/hybrids thereof. The softwood feedstocks
for the present disclosure may be selected from pine (e.g. Pinus
radiata, Pinus taeda); spruce; and combinations/hybrids
thereof.
[0028] Annual fibre feedstocks include biomass derived from annual
plants, plants which complete their growth in one growing season
and therefore must be planted yearly. Examples of annual fibres
include: flax, cereal straw (wheat, barley, oats), sugarcane
bagasse, rice straw, corn stover, hemp, fruit pulp, alfa grass,
switchgrass, and combinations/hybrids thereof. Industrial residues
like corn cobs, fruit peals, seeds, etc. may also be considered
annual fibres since they are commonly derived from annual fibre
biomass such as edible crops and fruits. For example, the annual
fibre feedstock may be selected from wheat straw, corn stover, corn
cobs, sugar cane bagasse, and combinations/hybrids thereof.
[0029] The derivatives of native lignin will vary with the type of
process used to separate native lignins from cellulose and other
biomass constituents. Preparations very similar to native lignin
can be obtained by (1) solvent extraction of finely ground wood
(milled-wood lignin, MWL) or by (2) acidic dioxane extraction
(acidolysis) of wood. Derivatives of native lignin can be also
isolated from biomass pre-treated using (3) steam explosion, (4)
dilute acid hydrolysis, (5) ammonia fibre expansion, (6)
autohydrolysis methods. Derivatives of native lignin can be
recovered after pulping of lignocellulosics including industrially
operated (3) kraft and (4) soda pulping (and their modifications)
and (5) sulphite pulping. In addition, a number of various pulping
methods have been developed but not industrially introduced. Among
them four major "organosolv" pulping methods tend to produce
highly-purified lignin mixtures. The first organosolv method uses
ethanol/solvent pulping (aka the Alcell.RTM. process); the second
organosolv method uses alkaline sulphite anthraquinone methanol
pulping (aka the "ASAM" process); the third organosolv process uses
methanol pulping followed by methanol, NaOH, and anthraquinone
pulping (aka the "Organocell" process); the fourth organosolv
process uses acetic acid/hydrochloric acid or formic acid pulping
(aka the "Acetosolv" process).
[0030] It should be noted that kraft pulping, sulphite pulping, and
ASAM organosolv pulping will generate derivatives of native lignin
containing significant amounts of organically-bound sulphur which
may make them unsuitable for certain uses. Acid hydrolysis, soda
pulping, steam explosion, Alcell.RTM. pulping, Organocell pulping,
and Acetosolv pulping will generate derivatives of native lignin
that are sulphur-free or contain low amounts of inorganic
sulphur.
[0031] Organosolv processes, particularly the Alcell.RTM. process,
tend to be less aggressive and can be used to separate highly
purified lignin derivatives and other useful materials from biomass
without excessively altering or damaging the native lignin building
blocks. Such processes can therefore be used to maximize the value
from all the components making up the biomass. Organosolv
extraction processes however typically involve extraction at higher
temperatures and pressures with a flammable solvent compared to
other industrial processes and thus are generally considered to be
more complex and expensive.
[0032] A description of the Alcell.RTM. process can be found in
U.S. Pat. No. 4,764,596 (herein incorporated by reference). The
process generally comprises pulping or pre-treating a fibrous
biomass feedstock with primarily an ethanol/water solvent solution
under conditions that include: (a) 60% ethanol/40% water, (b)
temperature of about 180.degree. C. to about 210.degree. C., (c)
pressure of about 20 atm to about 35 atm, and (d) a processing time
of 5-120 minutes.
[0033] Derivatives of native lignin are fractionated from the
native lignins into the pulping liquor which also receives
solubilised hemicelluloses, other carbohydrates and other
extractives such as resins, organic acids, phenols, and tannins.
Organosolv pulping liquors comprising the fractionated derivatives
of native lignin and other extractives from the fibrous biomass
feedstocks, are often called "black liquors". The organic acid and
extractives released by organosolv pulping significantly acidify
the black liquors to pH levels of about 5 and lower. After
separation from the cellulosic pulps produced during the pulping
process, the derivatives of native lignin are recovered from the
black liquors by depressurization followed by flashing with cold
water which will cause the fractionated derivatives of native
lignin to precipitate thereby enabling their recovery by standard
solids/liquids separation processes. Various disclosures
exemplified by U.S. Pat. No. 7,465,791 and PCT Patent Application
Publication No. WO 2007/129921, describe modifications to the
Alcell organosolv process for the purposes of increasing the yields
of fractionated derivatives of native lignin recovered from fibrous
biomass feedstocks during biorefining. Modifications to the Alcell
organosolv process conditions included adjusting: (a) ethanol
concentration in the pulping liquor to a value selected from a
range of 35%-85% (w/w) ethanol, (b) temperature to a value selected
from a range of 100.degree. C. to 350.degree. C., (c) pressure to a
value selected from a range of 5 atm to 35 atm, and (d) processing
time to a duration from a range of 20 minutes to about 2 hours or
longer, (e) liquor-to-wood ratio of 3:1 to 15:1 or higher, (f) pH
of the cooking liquor from a range of 1 to 6.5 or higher if a basic
catalyst is used.
[0034] The derivatives of native lignin herein may be obtained by:
[0035] (a) pulping a fibrous biomass feedstock with an organic
solvent/water solution, [0036] (b) separating the cellulosic pulps
or pre-treated substrates from the pulping liquor or pre-treatment
solution, [0037] (c) recovering derivatives of native lignin.
[0038] The organic solvent may be selected from short chain primary
and secondary alcohols, such as such as methanol, ethanol,
propanol, and combinations thereof. For example, the solvent may be
ethanol. The liquor solution may comprise about 20%, by weight, or
greater, about 30% or greater, about 50% or greater, about 60% or
greater, about 70% or greater, of ethanol.
[0039] Step (a) of the process may be carried out at a temperature
of from about 100.degree. C. and greater, or about 120.degree. C.
and greater, or about 140.degree. C. and greater, or about
160.degree. C. and greater, or about 170.degree. C. and greater, or
about 180.degree. C. and greater. The process may be carried out at
a temperature of from about 300.degree. C. and less, or about
280.degree. C. and less, or about 260.degree. C. and less, or about
240.degree. C. and less, or about 220.degree. C. and less, or about
210.degree. C. and less, or about 205.degree. C. and less, or about
200.degree. C. and less.
[0040] Step (a) of the process may be carried out at a pressure of
about 5 atm and greater, or about 10 atm and greater, or about 15
atm and greater, or about 20 atm and greater, or about 25 atm and
greater, or about 30 atm and greater. The process may be carried
out at a pressure of about 150 atm and less, or about 125 atm and
less, or about 115 atm and less, or about 100 atm and less, or
about 90 atm and less, or about 80 atm and less.
[0041] The fibrous biomass may be treated with the solvent solution
of step (a) for about 1 minute or more, about 5 minutes or more,
about 10 minutes or more, about 15 minutes or more, about 30
minutes or more. The fibrous biomass may be treated with the
solvent solution of step (a) at its operating temperature for about
360 minutes or less, about 300 minutes or less, about 240 minutes
or less, about 180 minutes or less, about 120 minutes or less.
[0042] The pH of the pulp liquor may, for example, be from about 1
to about 6, or from about 1.5 to about 5.5.
[0043] The weight ratio of liquor to biomass may be any suitable
ratio. For example, from about 4 or 5:1 to about 15:1, from about
5.5:1 to about 10:1; from about 6:1 to about 8:1.
[0044] The lignin derivatives herein may, for example, have an
aliphatic hydroxyl content of from about 0.1 mmol/g to about 8
mmol/g; about 0.4 mmol/g to about 7 mmol/g; about 0.6 mmol/g to
about 6.5 mmol/g; about 0.8 mmol/g to about 6 mmol/g.
[0045] The term "aliphatic hydroxyl content" refers to the quantity
of aliphatic hydroxyl groups in the lignin derivatives and is the
arithmetic sum of the quantity of primary and secondary hydroxyl
groups (OHal=OHpr+OHsec). The aliphatic hydroxyl content can be
measured by quantitative .sup.13C high resolution NMR spectroscopy
of acetylated and non-acetylated lignin derivatives, using, for
instance, 1,3,5-trioxane and tetramethyl silane (TMS) as internal
reference. For the data analysis "BASEOPT" (DIGMOD set to baseopt)
routine in the software package TopSpin 2.1.4 was used to predict
the first FID data point back at the mid-point of .sup.13C r.f.
pulse in the digitally filtered data was used. For the NMR spectra
recording a Bruker AVANCE II digital NMR spectrometer running
TopSpin 2.1 was used. The spectrometer used a Bruker 54 mm bore
Ultrashield magnet operating at 14.1 Tesla (600.13 MHz for .sup.1H,
150.90 MHz for .sup.13C). The spectrometer was coupled with a
Bruker QNP cryoprobe (5 mm NMR samples, .sup.13C direct observe on
inner coil, .sup.1H outer coil) that had both coils cooled by
helium gas to 20K and all preamplifiers cooled to 77K for maximum
sensitivity. Sample temperature was maintained at 300 K.+-.0.1 K
using a Bruker BVT 3000 temperature unit and a Bruker BCU05 cooler
with ca. 95% nitrogen gas flowing over the sample tube at a rate of
800 L/h.
[0046] The present lignin derivatives may have any suitable
phenolic hydroxyl content such as from about 2 mmol/g to about 8
mmol/g. For example, the phenolic hydroxyl content may be from
about 2.5 mmol/g to about 7 mmol/g; about 3 mmol/g to about 6
mmol/g.
[0047] The present lignin derivatives may have any suitable number
average molecular weight (Mn). For example, the Mn may be from
about 200 g/mol to about 3000 g/mol; about 350 g/mol to about 2000
g/mol; about 500 g/mol to about 1500 g/mol.
[0048] The present lignin derivatives may have any suitable weight
average molecular weight (Mw). For example, the Mw may be from
about 500 g/mol to about 5000 g/mol; about 750 g/mol to about 4000
g/mol; about 900 g/mol to about 3500 g/mol.
[0049] The present lignin derivatives may have any suitable
polydispersity (D). For example, the D may be from about 1 to about
5; from about 1.2 to about 4; from about 1.3 to about 3.5; from
about 1.4 to about 3.
[0050] The present lignin derivatives are preferably hydrophobic.
Hydrophobicity may be assessed using contact angle
measurements.
[0051] The present lignin derivatives may comprise alkoxy groups.
For example, the present lignin derivatives may have an alkoxy
content of 2 mmol/g or less; about 1.4 mmol/g or less; about 1.2
mmol/g or less; about 1 mmol/g or less; about 0.8 mmol/g or less;
about 0.7 mmol/g or less; about 0.6 mmol/g or less; about 0.5
mmol/g or less; about 0.4 mmol/g or less; about 0.3 mmol/g or less.
The present lignin derivatives may have an alkoxy content of 0.001
mmol/g or greater, about 0.01 mmol/g of greater, about 0.05 mmol/g
or greater, about 0.1 mmol/g or greater.
[0052] The present lignin derivatives may comprise ethoxy groups.
It has been found that derivatives of native lignin having an
ethoxy content of 0.45 mmol/g or greater result in PF-resins having
acceptable bond-strengths. For example, about 0.5 mmol/g or
greater; about 0.6 mmol/g or greater; about 0.7 mmol/g or greater;
about 0.8 mmol/g or greater; about 0.9 mmol/g or greater; about 1
mmol/g or greater; about 1.1 mmol/g or greater; about 1.2 mmol/g or
greater. The present lignin derivatives may, for example, have an
ethoxy content of about 3.75 mmol/g or less; 3.5 mmol/g or less;
3.25 mmol/g or less; 3 mmol/g or less; 2.75 mmol/g or less; 2.5
mmol/g or less; 2.25 mmol/g or less; 2 mmol/g or less; 1.9 mmol/g
or less; 1.8 mmol/g or less; 1.7 mmol/g or less; 1.6 mmol/g or
less; 1.5 mmol/g or less; 1.4 mmol/g or less; 1.3 mmol/g or
less.
[0053] The present lignin derivatives may comprise other alkoxy
groups apart from ethoxy groups such as C.sub.1-C.sub.6 alkoxy
groups; C.sub.1-C.sub.4 alkoxy groups; C.sub.1-C.sub.3 alkoxy
groups; methoxy and/or propoxy.
[0054] Quantification of the alkoxy groups can be performed using
high resolution .sup.13C NMR spectroscopy. For example,
quantification of ethoxyl groups can be performed by high
resolution .sup.13C NMR spectroscopy. Identification of ethoxyl
groups can be confirmed by 2D NMR HSQC spectroscopy. 2D NMR spectra
may be recorded by a Bruker 700 MHz UltraShield Plus standard bore
magnet spectrometer equipped with a sensitive cryogenically cooled
5mm TCI gradient probe with inverse geometry. The acquisition
parameters are the following: standard Bruker pulse program
hsqcetgp, temperature of 298 K, a 90.degree. pulse, 1.1 sec pulse
delay (dl), and acquisition time of 60 msec.
[0055] Quantification of ethoxyl groups was performed using
quantitative .sup.13C NMR spectroscopy. Identification of ethoxyl
groups was confirmed by 2D NMR HSQC spectroscopy. 2D NMR spectra
were recorded by a Bruker 700 MHz UltraShield Plus standard bore
magnet spectrometer equipped with a sensitive cryogenically cooled
5mm TCI gradient probe with inverse geometry. The acquisition
parameters were as follow: standard Bruker pulse program hsqcetgp,
temperature of 298 K, a 90.degree. pulse, 1.1 sec pulse delay (dl),
and acquisition time of 60 msec.
[0056] The derivatives of native lignin herein may be incorporated
into resin compositions as epoxy resins, urea-formaldehyde resins,
phenol-formaldehyde resins, polyimides, isocyanate resins, and the
like. The lignin derivatives herein are particularly useful in
phenolic resins.
[0057] Phenol-formaldehyde resins can be produced by reacting a
molar excess of phenol with formaldehyde in the presence of an acid
catalyst, such as sulfuric acid, hydrochloric acid or, oxalic acid
(usually in an amount of 0.2 to 2% by weight based on the phenol)
or a basic catalyst such as sodium hydroxide. To prepare the
so-called "high ortho" novolac resins, the strong acid catalyst is
typically replaced by a divalent metal oxide (e.g. MgO and ZnO) or
an organic acid salt of a divalent metal (e.g. zinc acetate or
magnesium acetate) catalyst system. The resins so-produced are
thermoplastic, i.e., they are not self-crosslinkable. Such novolac
resins are converted to cured resins by, for example, reacting them
under heat with a crosslinking agent, such as hexamine (also called
hexa or hexamethylenetetramine), or for example, by mixing them
with a solid acid catalyst and paraformaldehyde and reacting them
under heat. Novolac resins also may be cured with other cross
linkers such as resoles and epoxies. The lignin derivative may be
mixed with phenol at any suitable ratio. For example, a
lignin:phenol weight ratio of about 1:10 to about 10:1, about 1:8
to about 8:1, about 1:6 to about 6:1, about 1:5 to about 5:1, about
1:4 to about 4:1, about 1:3 to about 3:1, about 1:2 to about 2:1,
about 1:1. The lignin derivative may comprise any suitable amount
of the total resin composition. For example, from about 1%, by
weight, or greater, about 0.5% or greater, about 10% or greater,
about 20% or greater, about 30% or greater, about 35% or greater,
about 40% or greater, of the total resin composition. The lignin
derivative may comprise from about 80%, by weight, or less, about
60% or less, about 50% or less, of the total resin composition. The
resin compositions may comprise a variety of other optional
ingredients such as adhesion promoters; biocides (e.g.
bactericides, fungicides, and moldicides), anti-fogging agents;
anti-static agents; bonding, blowing and foaming agents;
[0058] dispersants; fillers and extenders; fire and flame
retardants and smoke suppressants; impact modifiers; initiators;
lubricants; micas; pigments, colorants and dyes; plasticizers;
processing aids; release agents; silanes, titanates and zirconates;
slip and anti-blocking agents; stabilizers; stearates; ultraviolet
light absorbers; foaming agents; defoamers; hardeners; odorants;
deodorants; antifouling agents; viscosity regulators; waxes; and
combinations thereof.
[0059] The present disclosure provides binder compositions
comprising any suitable amount of MDI and any suitable amount of
lignin derivative. For example, the binder compositions may
comprise about 0.1% to about 25%, about 1% to about 15%, about 3%
to about 10%, of lignin derivative by weight of the total binder
composition.
[0060] The present disclosure provides a method of incorporating
derivatives of native lignin in compositions comprising MDI. In
particular, the method comprises: [0061] a) providing a composition
comprising derivatives of native lignin in a suitable solvent;
[0062] b) providing a resin composition comprising MDI; [0063] c)
mixing the compositions; and [0064] d) removing the solvent.
[0065] The present method provides for the modification of a MDI
adhesive resin (usually a liquid) with an extracted lignin (usually
a solid, dried before use) to form a relatively stable liquid
MDI--lignin adhesive resin. The lignin may be dissolved in a
suitable solvent such as acetone. The resulting solution may then
be mixed with liquid MDI resins at a predetermined ratio. The
solvent may then be extracted by, for example, vacuum distillation
at low temperatures. During the distillation, MDI reacts with the
lignin to form a relatively homogenous and stable MDI-lignin resin
system. The solvent may be recovered and reused.
[0066] The present compositions may be incorporated into any
suitable fibreboard or similar material. For example, low density
fibreboard (LDF), medium density fibreboard (MDF), high density
fibreboard (HDF), strawboard & other agricultural
fibre/particle boards, oriented strand board (OSB), particle board,
termite-resistant OSB made with a pMDI resin and borate compounds,
termite-resistant MDF made with a pMDI resin and borate compounds,
wood fibre insulation board (WFIB), polyurethane foams, and the
like. The present compositions have be useful in foundry resins.
The present disclosure provides a method for producing a fibreboard
comprising: [0067] a) providing fibres to a blowline; [0068] b)
providing a binder comprising polymeric MDI and a derivative of
native lignin; [0069] c) treating the fibres with the binder;
[0070] d) preferably at least partially drying the treated fibres;
and [0071] e) pressing the treated fibres to form a fibreboard.
[0072] Fibreboard is typically manufactured via a multi-step
process. Wood chips, or other suitable materials, are fed into a
digester where they are exposed to steam and/or high pressures in
order to soften them. The treated material is then fed into a
refiner where mechanical forces separate the component fibres. The
fibres exit the refiner via a "blowline" where they are transported
in steam. Typically, binders are added to the fibres in the
blowline. The hot, moist conditions in the blowline are such that
the isocyanates rapidly react with the water to form
polyureas--that is, they "precure".
[0073] Typically the blowline deposits the treated fibres in a
dryer, and then into pressing devices which produce the panels.
Ideally, polymerization of the binder into its final thermoset form
would take place in the press, not prior to pressing the fibreboard
into its final form. However, because isocyanates are so reactive
it is likely that a significant amount of isocyanate is converted
to polyurea prior to pressing. This can lead to the formation of
solids, which foul the blowline or the dryer. Also,
pre-polymerization renders a significant portion of the binder
inactive, reducing bonding efficiency. Furthermore, pre-cure can
lead to structuring of the surface of the panel before pressing.
This can lead to "crashing" of the surface during pressing and to a
correspondingly lower performance characteristics such as MOR and
MOE.
[0074] The preferred fibreboard products are manufactured from wood
fibres, although other cellulosic fibres may also be used,
including those manufactured from agricultural products.
[0075] The present disclosure provides a method of forming
fibreboard, and particularly medium density fibreboard. Processes
for production of medium density fibreboard are well known and a
process is described, generally, below.
[0076] In producing medium density fibreboard, a polyisocyanate
resin is applied directly to the hot and wet fibre material in the
blowline out of the refiner of a fibreboard manufacturing plant.
Generally, the material is first screened to remove oversized and
undersized material, e.g., fines and dirt. The material may also be
subjected to a washing step.
[0077] The material is conveyed to storage bins that feed
pressurized digester-refiner systems. The refiners refine the raw
material into fibre under steam pressure. The material passes from
the steam-pressurized digester into the refining section while
still under pressure, and this pressure is maintained during the
refining. A digester is provided for pre-steaming of the raw
material. Advantageously, molten wax is added to the material as
they are fed to the digester. Generally, the material is steamed in
the digester for about five to ten minutes at a pressure of about
550 kPa to 830 kPa.
[0078] As the material emerges from the digester, it passes through
a refiner, which is also operated under steam pressure. The
material is shredded into fibres in the refiner and then blown
through an orifice (i.e., the blow-valve) out of the refiner into
the "blowline". Typically, the steam pressure in the refiner can be
from about 550 kPa to 1030 kPa, with temperatures ranging from
about 140.degree. C. to 205.degree. C. The fibres which emerge from
the refiner into the blowline generally have a moisture content of
50% or higher, by weight, based on the total solids weight, and a
temperature of at least about 100.degree. C. to 204.degree. C.
(usually above about 118.degree. C.).
[0079] The present compositions may be introduced into the blowline
to treat the hot fibre. For example the binder may be added to the
material as it emerges from the refiner.
[0080] After refining, the material is conveyed through the
blowline into a flash tube dryer, where the fibre moisture content
is reduced to about 2% to 20%, by weight. Typically, the treated
fibre is in an air stream tube dryer for about 30 seconds, during
which time it is at a temperature of about 38.degree. C. to
260.degree. C.
[0081] After refining, treating with the binder, and drying, the
fibre and air are separated via a separator air cyclone. Next, the
fibre is transported to mechanical formers that uniformly lay down
the fibre on to a moving `forming line`.
[0082] The material can be treated in a pre-compressor to make it
easier to handle. After pre-compression, the material is cut into
desired lengths and fed into a conventional board-forming press,
such as a typical medium density fibreboard press having multiple
steam or oil heated platens, or a continuous press which
consolidates the material between two opposing steel belts. The
press consolidates and compresses the material to the desired
thickness while the heat cures the binder composition. Typically,
during the pressing operation the material is generally heated to a
temperature of about 121.degree. C. to 232.degree. C. and
compressed at about 690 kPa to 6900 kPa of pressure. Pressing times
are typically about 2 to 10 minutes.
[0083] The compositions of the present disclosure may be added to
the fibre material at any suitable quantity. For example, from
about 0.5% to about 25%, from about 1% to about 15%, from about 2%
to about 10%, from about 3% to about 8%, by weight based on the dry
weight of the fibre material.
[0084] MDF produced according to the present disclosure has a good
modulus of rupture (MOR) and modulus of elasticity (MOE) as well as
an acceptable internal bond (IB) strength.
EXAMPLES
Example 1
[0085] MDI/Lignin Production
[0086] Two batches of 10 g of powdered lignin derivative are
dissolved in two aliquots of 50 g of acetone to form 20% wt./wt.
solutions. 100 g of MDI (Rubinate 1780) is then mixed into one
solution and 200 g of MDI (Rubinate 1780) is mixed into the other.
The solutions are then subjected to vacuum distillation at room
temperature for 2 hours. This removes 95% of the acetone which can
be stored and re-used. The two compositions are stored and their
viscosities measured over a period of several days (Table 1). The
results indicate that the mixtures are not entirely stable but are
not so unstable as to be unusable.
TABLE-US-00001 TABLE 1 The viscosity and stability of the
MDI-lignin resins Viscosity (mPa s) Storage time 5% lignin mix 10%
lignin mix 0 600 1600 24 h 780 3600 6 days 880 9300 10 days --
11250 17 days 1350 --
[0087] In addition, 5 g and 10 g of hardwood lignin powder are
directly mixed with 100 g of MDI resin (Rubinate 1780). The
suspensions appear stable for at least 24 hours, but separation or
precipitation occurs over an extended period of time.
[0088] A sample of the 5% MDI-lignin mixture manufactured using
acetone, and one sample each from the 5% and 10% MDI-lignin
compositions made via direct mixing, were used to manufacture a
medium density fibreboard (MDF) using a standard blowline. The
three resultant boards were measured for their shear strength
(Table 2) according to the ABES method (Wescott, J. M., Birkeland,
M. J., Traska, A. E., New Method for Rapid Testing of Bond Strength
for Wood Adhesives, Heartland Resource Technologies Waunakee, Wis.,
U.S.A. and Frihart, C. R. and Dally, B. N., USDA Forest Service,
Forest Products Laboratory, Madison, Wis., U.S.A., Proceedings
30.sup.th Annual Meeting of The Adhesion Society, Inc., Feb. 18-21,
2007, Tampa Bay, Fla., USA).
TABLE-US-00002 TABLE 2 Shear strength of the mixes (yellow birch
veneer, thickness: 1.56 mm) Strength (MPa) Resin mix 150.degree.
C., 90 s 200.degree. C., 90 s 5% lignin (acetone 3.3 (1.2) 5.4
(0.7) solution) mixed MDI 5% lignin directly mixed 4.0 (0.6) 5.8
(0.8) with MDI 10% lignin directly 4.3 (1.1) 7.0 (1.9) mixed with
MDI
[0089] Further MDI-bonded MDF panels were made at pilot scale. Wood
fiber, which was dry and unresinated, was sourced from a Canadian
MDF mill. In a fiberboard pilot plant, a weighted amount of the
wood fiber was blended with a predetermined amount of pMDI resin or
lignin-modified pMDI resin and a predetermined amount of emulsion
wax in an air-suspension tube blender. Using the resulting
resinated wood fiber, a homogenous fiber mat was constructed in a
710 mm.times.710 mm forming box with Telflon sheets on top and
bottom of the mat, which was then hot pressed into a MDF panel by a
Dieffenbacker press (864 mm.times.864 mm) equipped with a PressMan
monitoring system.
[0090] Wood species: SPF
[0091] Fiber type: mechanically refined with a moisture content of
about 8.5%
[0092] Control resin: RUBINATE 1780 (pMDI) at 4% add-on rate (dry
wood basis)
[0093] Experimental resin: lignin--MDI containing 5% lignin at 4%
add-on rate (dry wood basis)
[0094] Wax: emulsion wax (58% solids) at 0.5% add-on rate (dry wood
basis)
[0095] Moisture content of blended fiber: 6.5%-7.5%
[0096] Target panel density: 768 kg/cu. m
[0097] Target panel thickness: 9.5 mm
[0098] Press temperature: 182 C (360 F)
[0099] Press time: 280 seconds
[0100] Pressing method: Press fast closed to 15% above target panel
thickness and then slow closed to target thickness over 60 seconds,
following by holding and degassing.
[0101] The resulting MDF panels were conditioned under ambient
conditions for 7 days, and then tested for vertical density
profile, average density, modulus of elasticity, modulus of
rupture, internal bond strength, and thickness swell and water
absorption after 24-hour water soak and compared to MDF made with
MDI alone, and to the American National Standard Institute ANSI STD
A208.2-2003 (Table 3).
TABLE-US-00003 TABLE 3 Press Press Resin Temp Time D Type Resin %
(.degree. F.) (sec.) (lb/ft.sup.3) IB (psi) IB/D MOR (psi) MOE
(Mpsi) WA (%) TS (%) MDI 4.0 360 280 48.6 204.3 .+-. 24.3 4.20
5,135 .+-. 437 0.468 .+-. 0.023 24.5 .+-. 1.8 15.0 .+-. 1.6 MDI-
4.0 360 280 48.6 161.0 .+-. 23.5 3.31 5,731 .+-. 434 0.528 .+-.
0.038 24.7 .+-. 2.2 17.4 .+-. 0.9 Lignin American N/A N/A N/A N/A
44-152 N/A 3,500 0.350 N/A N/A ANSI STD A208.2 (2003)
Example 2
[0102] Further testing was performed to compare OSB panel
performance for a lignin-phenol-formaldehyde resin (LPF) and a
commercial phenol-formaldehyde (PF) resin as adhesives for
[0103] OSB face layers and to evaluate the feasibility of replacing
commercial pMDI resin in OSB core layers with 30%, 40% and 50% LPF
resins.
OSB Panel Manufacturing:
TABLE-US-00004 [0104] Face Core Resin solids pMDI solids Lignin-PF
add-on rate add-on rate solids add-on Group No. Resin type (%) (%)
rate (%) 1 Commercial PF 3.00 2.00 0 2 Lignin-PF 3.00 2.00 0 3
Commercial PF 3.00 1.40 0.90 4 Commercial PF 3.00 1.20 1.20 5
Commercial PF 3.00 1.00 1.50
[0105] Wood species: Aspen
[0106] OSB strands: screened and dried to 2% moisture content.
[0107] Target mat moisture: 6%-7%
[0108] Face/core ratio: 50/50
[0109] Panel thickness: 7/16''
[0110] Panel dimension: 4'.times.8'.times. 7/16''
[0111] Target density: 38 lb/ft.sup.3
[0112] Face resin: PF or Ligin-PF at 3% solids add-on (warmed to
30.degree. C. before blending)
[0113] Core resin: pMDI/lignin-PF (100:0, 70:30.times.1.5,
60:40.times.1.5 and 50:50.times.1.5)
[0114] E-wax: EW58S at 1% solids add-on (58% solids diluted with
water to 50% solids)
[0115] Press temperature: 215.degree. C.
[0116] Press cycle time: 155 seconds
[0117] Hot stacking: Yes
[0118] Replicates: 4 for each group
[0119] Total number of panels produced: 20
Panel Test Results:
[0120] Concentrated static load 4-point tests according to the
American PS-2 standard
TABLE-US-00005 Group 1 2 3 4 5 Surface Commercial Lignin-
Commercial Commercial Commercial PF PF PF PF PF Resin Loading 3.00%
3.00% 3.00% 3.00% 3.00% Core pMDI- pMDI- Lignin*- Lignin*- Lignin*-
R1840 R1840 PF PF PF pMDI- pMDI- pMDI- R1840 R1840 R1840 Resin
Loading 0.90% 1.20% 1.50% 2.00% 2.00% 1.40% 1.20% 1.00% Density @
test 39.0 39.3 39.3 39.2 39.4 point (10'' .times. 10'') std 1.28
1.28 2.04 1.44 2.67 Thickness (inch) 0.43 0.434 0.44 0.44 0.43 std
0.01 0.01 0.01 0.01 0.01 Deflection (inch) 0.38 0.394 0.38 0.37
0.38 std 0.03 0.02 0.03 0.03 0.04 Ultimate Load (lbf) 444 386 432
433 402 std 38.1 36.8 59.1 46.6 44.6 fail/pass 1/15 12/4 4/12 4/12
7/9 APA PRP-108 (2001) Performance Criteria: Minimum Ultimate 400
lbf Load - Maximum Deflection @ 200 lbf 0.500 in *HPL .TM. lignin
(available from Lignol Innovations, Burnaby, Canada, V5G 3L1)
[0121] The average density, vertical density profile, internal bond
strength (TB), modulus of rupture (MOR), modulus of elasticity
(MOE), and thickness swelling (TS) and water absorption (WA) was
measured after 24-hour water soak.
TABLE-US-00006 MOR MOE (par- (par- IB/ TS allel) allel) IB Core-
Density (edge) WA Group (psi) (Mpsi) (psi) density (lb/ft.sup.3)
(%) (%) 1 4320 0.861 37.4 0.52 37.7 26.0 49.2 2 3574 0.801 27.7
0.37 38.6 37.9 62.9 3 4164 0.878 35.7 0.48 38.7 27.7 48.9 4 4539
0.905 28.1 0.40 37.8 27.7 51.6 5 4276 0.908 25.3 0.36 39.3 28.8
54.5
[0122] The above results demonstrate that it is feasible to use LPF
resin at 40% phenol replacement and that pMDI is an excellent
cross-linker for LPF.
* * * * *