U.S. patent application number 11/773835 was filed with the patent office on 2008-01-03 for resins and adhesive formulations therewith.
Invention is credited to Abhay K. Deshpande, George A. Locko.
Application Number | 20080000389 11/773835 |
Document ID | / |
Family ID | 34226082 |
Filed Date | 2008-01-03 |
United States Patent
Application |
20080000389 |
Kind Code |
A1 |
Locko; George A. ; et
al. |
January 3, 2008 |
Resins and Adhesive Formulations Therewith
Abstract
A process for producing rosin resins comprising reacting
together rosin and phenolic compound and/or terpene-phenol resin,
in the presence of a Bronsted acid. These resins may be used as
tackifiers in adhesive formulations, including chloroprene contact
cements.
Inventors: |
Locko; George A.; (US)
; Deshpande; Abhay K.; (US) |
Correspondence
Address: |
ARIZONA CHEMICAL COMPANY;c/o Bo Segers
P.O. Box 550850
Jacksonville
FL
32255
US
|
Family ID: |
34226082 |
Appl. No.: |
11/773835 |
Filed: |
July 5, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10655162 |
Sep 4, 2003 |
|
|
|
11773835 |
Jul 5, 2007 |
|
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Current U.S.
Class: |
106/287.28 ;
527/603 |
Current CPC
Class: |
C09F 1/04 20130101; C08L
93/04 20130101 |
Class at
Publication: |
106/287.28 ;
527/603 |
International
Class: |
C04B 7/02 20060101
C04B007/02; C08G 8/34 20060101 C08G008/34 |
Claims
1. A process for producing a resin, the process comprising reacting
together rosin and a co-reactant in the presence of a Bronsted
acid, where the co-reactant is a phenolic compound or a
terpene-phenol resin.
2. The process of claim 1 wherein rosin is reacted with a
terpene-phenol resin.
3. The process of claim 2 wherein the terpene-phenol resin has a
softening point of 125-150.degree. C.
4. The process of claim 2 wherein rosin and terpene-phenol are
reacted together in a rosin:terpene-phenol weight ratio of 40:60 to
60:40.
5. The process of claim 1 wherein rosin is reacted with phenol.
6. The process of claim 5 wherein rosin and phenol are reacted
together in a rosin:phenol weight ratio of 70:30 to 90:10.
7. The process of claim 1 wherein rosin is reacted with
C.sub.1-C.sub.12 alkylphenol.
8. The process of claim 2 wherein a terpene selected from the group
consisting of limonene, dipentene, .alpha.-pinene, .beta.-pinene
and .delta.-3-carene is used to prepare the terpene-phenol
resin.
9. The process of claim 1 wherein the Bronsted acid is a sulfonic
acid or a sulfuric acid.
10. The process of claim 9 wherein the sulfonic acid is
para-toluene sulfonic acid.
11. A resin produced by the process of claim 1, having a softening
point of 115-150.degree. C., an acid number of 10-85, a Mw of
550-1400, a Mn of 405-750, and a neat Gardner color of 6-12.
12. The resin produced by the process of claim 2.
13. The resin of claim 2 having an acid number of 10-50.
14. The resin produced by the process of claim 4.
15. The resin of claim 14 having an acid number of 30-85.
16. An article of manufacture comprising chloroprene and a resin
produced by the process of claim 1.
17. An article of manufacture comprising chloroprene and a resin
produced by the process of claim 2.
18. An article of manufacture comprising chloroprene and a resin
produced by the process of claim 5.
19. A process for preparing a chloroprene cement comprising
combining chloroprene, a metal oxide, hydrocarbon solvent, and the
resin of claim 12.
20. A process for preparing a chloroprene cement comprising
combining chloroprene, a metal oxide, hydrocarbon solvent, and the
resin of claim 14.
Description
RELATED APPLICATION DATA
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/655,162, filed Sep. 4, 2003, the
application of which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to rosin-derived resins,
including the use of such resins as a tackifier in adhesive
formulations.
[0004] 2. Description of the Related Art
[0005] A tackifier resin is a material that enhances the adhesive
properties of an adhesive formulation, where another major
component of the formulation is a base polymer, e.g., a rubber. The
use of rosin and rosin derivatives to form tackifier resins is well
known in the art (see, e.g., Kennedy et al., "Rosin in Adhesive
Tackifiers," Naval Stores (Zinkel and Russell, Eds.), Chapter 18,
Pulp Chemicals Association (1989)). Rosin-based tackifier resins
make a significant contribution to the performance properties of an
adhesive formulation, for example, the tackiness, peel-resistance
and ease of surface wetting of the formulation are impacted by the
selection of the tackifier.
[0006] One type of adhesive composition is known as contact cement
or contact adhesive. Contact cements are a type of adhesive product
used to bond two substrates together. In a typical use of contact
cement, two substrates to be bonded together are each coated with
the cement, and the cement is allowed to dry briefly before
proceeding. The substrates are then brought together so that the
cement domain on one substrate establishes contact with the cement
domain on the other substrate. The adhesivity of the cement is
sufficiently strong so that once contact between cement domains is
established, only a small amount of pressure (e.g., the amount of
pressure put forth by normal human physical strength) is needed to
forge a strong adhesive bond. This bond is typically instantaneous,
and additional pressure (such as by clamping the substrates
together) is normally not needed to maintain the bond.
[0007] Contact cements often contain tackifier and a polymer such
as chloroprene polymer or thermoplastic rubber. Cements formulated
using thermoplastic rubber may be solvent-based, while cements
formulated using chloroprene polymer may be solvent-based or
latex-based. Contact cements are frequently used as, for example,
automotive adhesives, construction adhesives, and laminating
adhesives.
[0008] The following patents are directed to the use of
rosin-derived resins in adhesive compositions, including contact
cements:
[0009] U.S. Pat. No. 5,977,222 (1999), assigned to Tosoh
Corporation, is directed to chloroprene-containing adhesive
compositions. The tackifier used in the adhesive compositions may
include rosin and rosin derivatives.
[0010] U.S. Pat. No. Re. 29.157 (1977) and U.S. Pat. No. 3,617,591
(1971), both assigned to Schenectady Chemicals, Inc., are directed
to adhesive compositions comprising chloroprene and the heat
reaction product of zinc resinate and an alkaline-condensed alkyl-
or aryl-substituted phenol formaldehyde resin. Rosin is disclosed
as an optional component of the adhesive compositions.
[0011] British Patent Specification 663,823 (1951), assigned to
Minnesota Mining and Manufacturing Company, is directed to
butadiene-styrene copolymer adhesive compositions for
pressure-sensitive adhesive tapes, where these tapes may include
rosin or terpene.
[0012] There is a need in the art for improved tackifier resins,
particularly for contact cement adhesive compositions. The present
invention fulfills this need and provides other related advantages
as described below.
BRIEF SUMMARY OF THE INVENTION
[0013] Briefly, in one aspect, the present invention provides a
process for producing a resin comprising reacting together rosin
and at least one of a phenolic compound and a terpene-phenol resin,
in the presence of a Bronsted acid. In an optional aspect the rosin
is gum rosin, while in a separate optional aspect the Bronsted acid
is a sulfonic acid or a sulfuric acid. The present invention also
provides a resin produced by this process. The resin produced by
this process may be characterized by, for example, one or more of:
a softening point of 115-150.degree. C., an acid number of 10-85, a
Mw of 550-1400, a Mn of 405-750, and a neat Gardner color of
6-12.
[0014] In one aspect of the present invention, the process for
producing a resin comprises reacting together rosin and
terpene-phenol resin, where in preferred aspects the terpene-phenol
resin has a softening point of about 125-150.degree. C. and/or the
rosin and terpene-phenol are reacted together in a
rosin:terpene-phenol weight ratio of about 40:60 to about 60:40.
Exemplary terpenes used to prepare the terpene-phenol resin
include, without limitation, d-limonene, dipentene, .alpha.-pinene,
.beta.-pinene, and .delta.-3-carene. The present invention also
provides a resin produced by this process. For example, a resin
produced by this process may be characterized by one or more of: a
softening point of 115-150.degree. C., an acid number of 10-50, a
Mw of 550-1400, a Mn of 405-750, and a neat Gardner color of
6-12.
[0015] In another aspect of the present invention, the process for
producing a resin comprises reacting together rosin and phenolic
compound. Preferably the rosin and phenolic compound are reacted
together in a rosin:phenolic compound weight ratio of about 70:30
to about 90:10. The present invention also provides a resin
produced by this process. For example, a resin produced by this
process may be characterized by one or more of: a softening point
of 115-150.degree. C., an acid number of 30-85, a Mw of 550-1400, a
Mn of 405-750, and a neat Gardner color of 6-12.
[0016] In another aspect, the present invention provides an article
of manufacture comprising chloroprene and a resin of the present
invention. The article of manufacture may further comprise, for
example, a metal oxide and hydrocarbon solvent. The present
invention also provides a method for preparing a chloroprene
cement, where the method comprises combining chloroprene, a metal
oxide, hydrocarbon solvent and a resin (either RP or RTP) of the
present invention.
[0017] These and other aspects of the invention will be evident
upon reference to the following detailed description of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] In various aspects, the present invention provides
rosin-terpene-phenol resin (or "RTP resin"), a process for making
RTP resin, contact cements containing the RTP resin, and processes
for making and using the contact cements. The present invention
also provides rosin-phenol resin (or "RP resin"), a process for
making RP resin, contact cements containing the RP resin, and
processes for making and using the contact cements. It has been
surprisingly found that use of the resins of the present invention
in contact cement formulations results in significant enhancement
of adhesion properties over the contact cement formulations known
heretofore in the art. This enhancement of adhesion finds
particular relevance in holding together objects undergoing high
levels of shear stress, such as in bonding of canvas running shoe
components under conditions of heavy use.
[0019] Thus, in one embodiment the present invention provides a
process for producing a resin comprising reacting together rosin
and at least one of phenol and terpene-phenol resin, in the
presence of a Bronsted acid. Usage of phenol in this process
produces a rosin-phenol resin product ("RP resin"), while usage of
terpene-phenol resin produces a rosin-terpene-phenol resin product
("RTP resin"). Before providing details of how these reactants may
be combined and reacted together, a brief description of these
reactants will be provided. In this description, and throughout the
present specification and claims, the terms "a" and "an" refer to
one or more of the referenced term. For example, the term "a
phenolic compound" includes both one and several phenolic
compounds.
Rosin
[0020] Rosin is mainly a mixture of C.sub.20 tricyclic fused-ring
monocarboxylic acids, typified by pimaric and abietic acids, where
these individual acids are commonly referred to as "resin acids."
Rosin suitable for the use in the present invention can be obtained
from many sources, and can have a wide range of purities. For
example, wood rosin may be employed in the present invention, where
wood rosin is obtained from Pinus stumps after harvesting the
stumps, chipping the stumps into small chips, extracting the chips
with hexane or higher-boiling paraffin, and distilling the hexane
or paraffin to yield wood rosin. Another suitable rosin is tall oil
rosin, which is a by-product of the Kraft (i.e., sulfate) pulping
process for making paper. In this pulping process, pinewood is
digested with alkali and sulfide, producing tall oil soap and crude
sulfate turpentine as by-products. Acidification of this soap
followed by fractionation of the crude tall oil yields tall oil
rosin and fatty acids. Depending on the fractionation conditions,
the tall oil rosin used in the present invention may contain
variable amounts of fatty acids.
[0021] Gum rosin, which is the name given to rosin that is obtained
after scoring a pine tree, collecting the exudate sap, and then
distilling away the volatile components, may also be employed in
this invention. An exemplary gum rosin is (without limitation)
Chinese gum rosin. In the present invention, the use of gum rosin
as the rosin component typically affords resins with higher
softening points than are obtained from other types of rosin.
Accordingly, the rosin component of the present invention is
preferably gum rosin. The use of gum rosin also tended to provide a
higher yield of product.
[0022] Rosin may be obtained from many commercial suppliers. For
example, standards grades of rosin may be obtained from Arizona
Chemical (Jacksonville, Fla.) under the UNI-TOL.RTM., ACINTOL.RTM.
or SYLVAROS.RTM. trademarks.
Phenolic Compounds
[0023] In addition to rosin, the RP resins of the present invention
are prepared from a phenolic compound. Phenolic compounds are
compounds that include a hydroxy-substituted phenyl group, i.e., an
optionally substituted phenol moiety. The molecular formula of
phenol is C.sub.6H.sub.5OH. A substituted phenol results when one
or more of the hydrogens attached to a carbon is replaced with a
different group, i.e., a substituent. Phenolic compounds suitable
for use as a component of the resin-forming composition of the
invention include, without limitation, phenol, C.sub.1-12
alkylphenols (i.e., phenol having one or more alkyl substituents,
where an alkyl substituent has from 1 to 12 carbons), arylphenols,
aralkylphenols, cresols, 1,3,5-xylenols, diphenylolpropane,
cumylphenol, bisphenol A, and the like. As used herein, alkyl
refers to a hydrocarbon structural domain containing exclusively
C--C and C--H single bonds; aryl refers to a hydrocarbon structural
domain as an aromatic ring system; while aralkyl refers to a
hydrocarbon structural domain containing both aromatic and alkyl
moieties. In one aspect, the phenolic compound is phenol, while in
another aspect the phenolic compound is a mixture of phenolic
compounds that includes phenol. In one aspect, the phenolic
compound is C.sub.1-12alkylphenol, while in another aspect the
phenolic compound is a mixture of phenolic compounds that includes
C.sub.1-12 alkylphenol. In one aspect, the phenolic compound is a
small molecular weight compound, e.g., a compound having a
molecular weight of less than about 500, or less than about 400, or
less than about 300 g/mol. However, in another aspect the phenolic
compound is a polymer, e.g., a phenol-formaldehyde resin. Phenol is
a preferred phenolic compound. Phenolic compounds may be obtained
from known sources such as Aldrich Chemical (Milwaukee, Wis.).
[0024] Preferably, in the preparation of the RP resins, the rosin
and phenolic compound are reacted together in a rosin:phenolic
compound weight ratio of about 70:30 to about 90:10, more
preferably of about 75:25 to about 85:15, even more preferably of
about 80:20.
[0025] Preferably, in the preparation of the RP resin, the rosin
and phenolic compound provide the majority of the weight of the
reactants used to form the RP resin. Thus, in various optional
aspects of the invention the rosin and phenolic compound contribute
at least 55%, or at least 60%, or at least 65%, or at least 70%, or
at least 75%, or at least 80%, or at least 85%, or at least 90%, or
at least 95%, or at least 98%, or 100% of the weight of the
carbon-containing reactants used to form the RP resin.
Terpene-Phenol Resin
[0026] In the preparation of the RTP resins of the present
invention, rosin is reacted with a terpene-phenol resin. The
terpene-phenol resins ("TP resins") that may be used for the
above-disclosed process may be prepared by acid catalyzed
polymerization, in a suitable solvent, of one or more terpenes with
one or more phenolic compounds. Exemplary phenolic compounds are
described in the preceding section. This chemistry is well known in
the art (see, e.g., U.S. Pat. Nos. 5,723,566 and 5,844,063) and TP
resins are commercially available from many sources. For example,
terpene-phenol resins suitable for use in the above-disclosed
process of the present invention, include (without limitation)
commercial products designated as SLYVARES.RTM. TP96, TP300,
TP2040, TP2040HM, TP2019, TP7042 and TP3523 resins, sold by Arizona
Chemical Company (Jacksonville, Fla.).
[0027] Exemplary terpenes suitable for use in preparing a TP resin
include (without limitation) d-limonene, dipentene, .alpha.-pinene,
.beta.-pinene, and .delta.-3-carene, where each of these terpenes
is available from various commercial suppliers, e.g., Aldrich
Chemical (Milwaukee, Wis.), Arizona Chemical Company, Jacksonville,
Fla. (under trade names such as SYLVAPINE.RTM. A terpene,
SYLVAPINE.RTM. B terpene, SYLVAPINE.RTM. 405 terpene,
SYLVAPINE.RTM. 402, etc.), Bush Boake & Allen/International
Flavors and Fragrances, Jacksonville, FL (under trade names such as
UNITENE.RTM. LP terpene), and Millennium Specialty Chemicals,
Jacksonville, Fla. (under trade names such as MILLENNIUM.RTM. 2B13
terpene). Limonene may be obtained as a byproduct of the citrus
industry, while dipentene may be obtained by pyrolysis or catalytic
cracking of .alpha.-pinene. .beta.-Pinene monomer is commonly
obtained by distillation of crude sulfate turpentine, which is a
by-product of the paper industry. Resin-grade .beta.-pinene is
generally about 80% by weight .beta.-pinene and about 20% by weight
oc-pinene. More pure grades of .beta.-pinene, such as the so-called
aroma-chemical grade thereof, which is greater than 90% by weight
.beta.-pinene, may also be used in preparing the terpene resins.
Pure terpenes, and mixtures of terpenes, may be used to prepare the
TP resin.
[0028] Lewis acids may be used to facilitate the preparation of TP
resins, where suitable Lewis acids include, but are not limited to,
boron trifluoride and derivatives or complexes thereof, and strong
protic acids such as hydrofluoric and sulfuric acid. While the TP
resins will be prepared from terpene and phenolic compound, other
co-reactants may be utilized to prepare a TP resin. For example,
non-terpene olefins and dienes may be utilized as a co-reactant,
where suitable non-terpene olefins and dienes include, without
limitation, isobutylene, diisobutylene, 1-alkenes (e.g.,
1-octadecene), vinylcyclohexene, piperylene and dicyclopentadiene
streams obtained from steam cracking of petroleum distillates, and
vinylaromatics such as styrene, indene, methylstyrenes, and
alkylaromatic styrenes.
[0029] In optional aspects the TP resin used in the process of
making the resin of the present invention has a softening point in
the range of 95-150.degree. C., or 95-140.degree. C., or
95-130.degree. C., or 95-120.degree. C., or 95-110.degree. C., or
105-150.degree. C., or 105-140.degree. C., or 105-130.degree. C.,
or 105-120.degree. C., or 115-150.degree. C., or 115-140.degree.
C., or 115-1300C, or 125-150.degree. C., or 125-140.degree. C., or
135-150.degree. C., or 140-150.degree. C. The softening point of
the TP resin used in the process of making the resin of the present
invention is preferably in the range of about 115-150\.degree. C.,
more preferably in the range of about 125-150\.degree. C.
[0030] Preferably, in the preparation of the RTP resins of the
present invention, the rosin and TP resin are reacted together in a
rosin:TP resin weight ratio of about 40:60 to about 60:40, more
preferably of about 45:55 to about 55:45, even more preferably of
about 50:50.
[0031] Preferably, in the preparation of the RTP resin, the rosin
and TP resin provide the majority of the weight of the reactants
used to form the RTP 5 resin, while in various optional aspects the
rosin and TP resin contribute at least 55%, or at least 60%, or at
least 65%, or at least 70%, or at least 75%, or at least 80%, or at
least 85%, or at least 90%, or at least 95%, or at least 98%, or
100% of the weight of the carbon-containing reactants used to form
the RTP resin.
[0032] Bronsted acid
[0033] The resin and manufacturing process of the present invention
utilizes rosin and a co-reactant (either phenolic compound or
terpene-phenolic resin) and reacts these materials together in the
presence of a Bronsted acid. As used herein, the term "Bronsted
acid" has its usual meaning in the art, and refers to a reagent
that has the ability to donate protons to a reaction or another
reagent. Bronsted acids are well known, where exemplary Bronsted
acids include, without limitation, hydrochloric acid, nitric acid,
sulfuric acid, sulfonic acids, phosphoric acid, phosphonic acids,
acetic acid, and benzoic acid.
[0034] Preferred Bronsted acids for use in the present invention
are sulfuric and sulfonic acids. Sulfonic acids are compounds that
contain a moiety of molecular formula: --S(.dbd.O).sub.2(OH).
Examples of sulfuric and sulfonic acids include (without
limitation) sulfuric acid; optionally-substituted aliphatic
sulfonic acids such as methanesulfonic acid, ethanesulfonic acid,
propanesulfonic acid, butanesulfonic acid, trifluoromethanesulfonic
acid, and 4-decene-3-sulfonic acid; and optionally-substituted
aromatic sulfonic acids such as dodecyl benzenesulfonic acid,
tridecyl benzenesulfonic acid, cumenesulfonic acid, xylenesulfonic
acid, and para-toluenesulfonic acid. In a preferred aspect, the
Bronsted acid for use in the present invention is
para-toluenesulfonic acid (PTSA).
Reaction Conditions
[0035] The process of the present invention includes reacting
together rosin and a co-reactant. As used herein, the term
"reacting" or "reacting together" means that each of the listed
reactants is added to a reaction vessel under reaction conditions
such that each reactant reacts with either a) another reactant, or
b) a reaction product formed from two or more reactants. Thus, in
preparing a RP resin, both rosin and phenolic compound are placed
in a reaction vessel. In preparing a RTP resin, both rosin and the
terpene-phenolic compound are placed in a reaction vessel. In a
preferred embodiment, these are the only carbon-containing
reactants used to form the RP or RTP resins, however, in optional
embodiments, one or more additional carbon-containing reactants may
be utilized to prepare the RP or RTP resin.
[0036] The duration and temperature(s) of the reaction are
preferably selected in order to prepare a resin, where a resin has
a higher molecular weight than any of the resin-forming reactants.
The resin preferably has properties as discussed below. In order
for an RP-forming or RTP-forming reaction to occur, combinations of
the reactants must be exposed to an elevated temperature, e.g.,
temperature(s) in the range of about 50-300.degree. C., preferably
about 80-300.degree. C. At these elevated temperature, the
reactants undergo covalent bond-forming reactions with other
reactants, so that a resinous material, i.e., a relatively high
molecular weight material, is formed. In particular, esterification
is observed to occur, where esterification results when carboxylic
acid groups (from rosin) react with hydroxyl groups (from phenolic
compound or terpene phenol resin).
[0037] For example, each of the reactants may be combined in a
single reaction vessel, and the combination taken to elevated
temperature(s) so that the reactants react with one another to form
a resin of the present invention. This approach may be termed a
"one-pot" reaction process.
[0038] Alternatively, two or more (but less than all) reactants may
be combined in a single reaction vessel, and this combination taken
to elevated temperature(s) so that the reactants react with one
another to form an intermediate reaction product. The other
reactants are reacted with the intermediate reaction product (in
either the same or a different reaction vessel). Thus, the
invention provides that the reactants may be reacted with one
another in any order, at one or more elevated temperatures, to
obtain a resin of the present invention. It should be recognized
however that the same reactants (in terms of quantity and identity)
may form resins with different physical and performance properties,
depending on the precise manner in which the reactants are reacted
together.
[0039] The reaction temperature(s) is selected with the following
points in mind. The reaction temperature must be high enough that
the contents of the reaction vessel are sufficiently fluid to allow
those contents to be stirred. Higher temperatures are generally
preferred for reasons of economy, in order to provide a faster rate
of reaction. However, the reaction temperature should not be so
great that the reaction components boil out of the reaction vessel.
Nor should the temperature be so great that decomposition of the
reaction components or reaction products should occur.
[0040] In the preparation of the RP and RTP resins of the present
invention, the reaction may be carried out in a solvent. Preferably
the solvent is a nonpolar solvent, since the reaction components,
being reasonably nonpolar in nature, tend to solubilize more
readily in a nonpolar solvent than in a polar solvent. More
preferably the solvent is nonpolar with a high boiling point, since
the esterification process of the present invention produces water
as a by-product. By using a solvent with a boiling point greater
than 100.degree. C., water can be boiled out of the reaction
mixture to prevent the reaction from reversing direction, without
greatly affecting the volume of the solvent. Examples of such
solvents include (without limitation) xylene and toluene.
Resin Properties
[0041] In the present invention, the extent of esterification
achieved in the resin preparation may be regulated by the length of
time given the reaction process. More time allowed for
esterification will generally lower the acid number of the resin
product, as more rosin acid groups are converted to ester groups.
As used herein, acid number is equal to the amount of KOH base (in
milligrams) needed to neutralize one gram of resin product.
Preferably, the RTP resins of the present invention have an acid
number of about 10-85 or 10-80 or 10-75 or 10-70 or 10-65 or 10-60
or 10-55; more preferably the RTP resins of the present invention
have an acid number of about 10-50. Preferably, the RP resins of
the present invention have an acid number of about 10-85 or 15-85
or 20-85 or 25-85; more preferably the RP resins of the present
invention have an acid number of about 30-85. Samples may be taken
periodically from the reaction mixture and analyzed for acid
number, in order to monitor the extent of the reaction.
[0042] The duration of reaction time will also impact the molecular
weight of the resulting product. Typically, the molecular weight of
the resin product will increase as more time is provided for the
formation of covalent bonds in the reaction product. In a preferred
aspect, the resins produced by the process of the present invention
have a molecular weight (Mw) in the range of 550-1400, and Mn in
the range of 405-750. These molecular weight values are obtained
using gel permeation chromatography, in a suitable solvent such as
tetrahydrofuran, using polystyrene standards to calibrate the
retention times to molecular weight values.
[0043] The extent of esterification of the resin products may be
monitored by the following method. First, test samples of the
reaction mixture (about 6-7 9) are drawn periodically from the
reaction vessel, and quenched with an aqueous solution of sodium
carbonate (about 4-5% (w/v)). The organic layer of each test sample
is collected, heated to about 110.degree. C. for about 20 minutes,
and the remaining residue is weighed to determine the percentage of
the reaction mixture that is solid material. This residue can then
be subjected to an acid number determination using methods known to
those of ordinary skill in the art, with the degree of
esterification taken to be inversely proportional to the acid
number of each sample. Alternatively, or in addition, the sample
residue can be analyzed via infrared spectroscopy, comparing the
peak intensities at 1744 cm.sup.-1 (ester C.dbd.O) and 1696
cm.sup.-1 (acid C.dbd.O). The degree of esterification is taken to
be directly proportional to the peak intensity at 1744 cm.sup.-1
and inversely proportional to the peak intensity at 1696
cm.sup.-1.
[0044] The color of the resin products of the present invention can
be measured according to the Gardner color scale, where a score of
zero corresponds to a colorless composition, and a score of fifteen
corresponds to a red-brown composition. An accurate determination
of the Gardner color of a resin can be obtained with a Spectronic
301 spectrophotometer (Milton Roy, Rochester) set in the absorbance
(Abs) mode. The Spectronic 301 is a single beam, visible range
spectrophotometer that is microprocessor-controlled. The wavelength
range is 325 to 900 nm with an accuracy of .+-.2 nm and wavelength
precision of .+-.1 nm. The Spectronic 301 has a photometric range
of -0.1 to 2.5 Abs units. The Spectronic 301 requires a 30-minute
warmup to maintain these ranges accurately and is calibrated
annually using Milton Roy Spectronic standards. Wavelength and
photometric data are sent to an external compute by a built-in
RS232C port. The external computer interprets the data, absorbance
at wavelengths 200-700 nm in increments of 10 nm based upon the
Gardner colors standards. The data is translated using ASTM
standard E308 and provides a printout of both Gardner colors and
values. The Gardner values are a digital version of the Gardner
colors. For example, a Gardner color of 3- is equivalent to a
Gardner value of 2.50 to 2.82; a Gardner color of 3 is equivalent
to a Gardner value of 2.83 to 3.17; and a Gardner color of 3+ is
equivalent to a Gardner value of 3.17 to 3.49. The software is
available from Paul N. Gardner Company Inc. (Pompano Beach, Fla.).
In one aspect, the product resins of the present invention exhibit
a neat (i.e., solvent-free) Gardner color in the range of 6 to
12.
Adhesive Composition and Articles made therefrom
[0045] In another aspect, the present invention provides an
adhesive composition that includes a RP or RTP resin of the present
invention. One such adhesive composition is a contact cement.
Contact cements are well known in the art (see, e.g., U.S. Pat.
Nos. 5,733,958 and 5,897,412) and are available from many
commercial sources (see, e.g., Macco Adhesives, Cleveland Ohio
44115 USA; DAP Inc., Baltimore Md. 21224 USA; www.dap.com; and
Henkel Consumer Adhesives, Avon Ohio 44011 USA; www.henkelca.com).
Contact cements are frequently used in footwear manufacture,
however contact cements also find use in any situation where two
surfaces must be bonded together.
[0046] Contact cements are particularly useful when the article
being formed by bonding two or more pieces together will need to be
flexible during use, e.g., in shoes, fabrics, wood products, rubber
rafts, tires, etc. Accordingly, in one aspect, the present
invention provides an article of manufacture, e.g., a shoe, where
the article includes a rubber, e.g., a chloroprene rubber, and a
resin of the present invention, i.e., a RP or RTP resin.
[0047] In one aspect, the adhesive composition and article made
therefrom includes a RP or RTP resin in admixture with a rubber,
e.g., a natural rubber or a chloroprene rubber, and is a contact
cement. Chloroprene rubber, also known as polychloroprene, is a
preferred component of the adhesive composition, where DuPont Dow
Elastomers L.L.C. (Wilmington, DE, USA;
www.dupont-dow.com/neoprene) sells a suitable chloroprene rubber
under their NEOPRENE trademark. The contact cement formulation may
be in the form of a solid or an aqueous emulsion. In other optional
aspects, the composition and article made therefrom may further
comprise a metal oxide (such as, for example, magnesium oxide
and/or zinc oxide). The composition may also include a hydrocarbon
solvent, such as, for example, toluene or xylene.
[0048] Thus, the present invention provides a process for preparing
an adhesive composition, e.g., a contact cement, comprising
combining a polymer, e.g., a rubber such as chloroprene, with a RP
or RTP resin, optionally in the presence of one or more metal
oxides, and optionally in the presence of one or more insert
solvents. The composition is readily prepared by combining the
ingredients in a suitable container and then mixing until a
homogeneous composition results. The RP or RTP resin of the present
invention may be substituted for, or used in addition to, other
tackifier resins presently used in contact cements, and
particularly rosin-derived tackifier resins.
[0049] In one aspect, the contact cement is applied to a surface,
e.g., a cloth or rubber surface, and allowed to dry. The dried
contact cement is then contacted with another surface that has been
similarly treated, and the two surfaces are held together under
elevated temperature, e.g., about 100-150.degree. C. Upon cooling,
a laminated product is produced, where the two surfaces are
adhesively coupled together via the contact cement. Alternatively,
after the contact cement has been applied to a surface, but before
the contact cement has dried, a second surface is applied to the
contact cement-coated surface, and upon drying of the contact
cement, the two surfaces are adhesively bonded together.
[0050] Thus, the present invention provides a method of bonding two
surfaces together, where the method includes coating at least one
of the surfaces with a RP- or RTP-containing adhesive composition,
and then holding the two surfaces together under adhesion-promoting
conditions. A surface may be coated by spraying, brushing or
otherwise applying the adhesive onto the surface. The
adhesive-promoting conditions are a suitable combination of time
and temperature.
[0051] The following examples are provided for the purpose of
illustrating the present invention, and are not a limitation
thereon. Reagents were reagent grade or better as obtained from
sources such as Aldrich Chemical (Milwaukee, Wis.). SYLVARES.TM.
TP7042 terpene-phenol resin was from Arizona Chemical
(Jacksonville, Fla.). TAMANOL.TM. 803L terpene phenolic resin was
obtained from Arakawa Chemical (USA) Inc. (Chicago, Ill.;
www.arakawa-usa.com). Comparative examples are denoted by a letter
"C" following the example number.
EXAMPLE 1
Synthesis of RTP Resin
[0052] A solution of 100 g Chinese gum rosin in 175 g of xylene was
charged to a one-liter Morton flask equipped with an agitator, a
Dean-Stark trap filled with xylene and attached to a condenser, and
a thermocouple probe assembly with an inlet for nitrogen. The flask
was then further charged with a solution of 100 g SYLVARES.TM.
TP7042 terpene-phenol resin in 175 g of xylene. Following addition
of 12 g para-toluenesulfonic acid to the rosin-TP mixture, the
mixture was heated over an electric heating mantle and brought to
reflux. As the reaction was allowed to proceed, water formed by the
reaction (esterification by product) was collected at the bottom of
the Dean-Stark trap. The reaction mixture was allowed to reflux for
a total of about 7 hours, or until the desired level of
esterification was reached, as determined by one of the
esterification monitoring procedures described hereinbefore.
[0053] When the desired level of esterification was reached, the
reaction mixture was cooled to less than about 90.degree. C., and
the reaction was quenched by the addition of a sodium carbonate
solution (about 7.2 g in 150 mL water). The water was then removed
from the reaction flask as follows: after heating the quenched
mixture to about 75-80.degree. C. and agitating the reaction flask
for about 10 minutes, the mixture was allowed to separate into
layers and the aqueous layer was drawn off. The reaction mixture
was then treated with an additional 150 mL of water, and the water
removal procedure was repeated.
[0054] The remaining reaction mixture was then charged to a tared
4-neck round bottom flask equipped with an agitator, a condenser
via a 3-way take-off adapter, a thermocouple assembly, and a sparge
tube. The reaction mixture was heated to about 245.degree. C. with
agitation under constant nitrogen sparge (at a rate of about 2000
mL/min), with the solvent distilling off at about 140-170.degree.
C. Samples of the reaction mixture were extracted periodically (in
1-2 mL aliquots) under nitrogen purge, and analyzed for softening
point. The reaction was allowed to proceed under nitrogen sparge
until the desired softening point was reached. Then, the reaction
product was cooled and discharged, to afford an RTP tackifier resin
with a softening point of 149.7.degree. C. and a Gardner color of
8.9 (neat).
EXAMPLE 2
Synthesis of RP Resin
[0055] A solution of 160 g Chinese gum rosin in 275 g of xylene was
charged to a one-liter Morton flask equipped with an agitator, a
Dean-Stark trap filled with xylene and attached to a condenser, and
a thermocouple probe assembly with an inlet for nitrogen. The flask
was then further charged with a solution of 40 g phenol in 100 g of
xylene. Following addition of 9.6 g para-toluenesulfonic acid to
the rosin-phenol mixture, the mixture was heated over an electric
heating mantle and brought to reflux. As the reaction was allowed
to proceed, water formed by the reaction (esterification
by-product) was collected at the bottom of the Dean-Stark trap. The
reaction mixture was allowed to reflux for a total of about 7
hours, or until the desired level of esterification was reached, as
determined by one of the esterification monitoring procedures
described hereinbefore.
[0056] When the desired level of esterification was reached, the
reaction mixture was cooled to less than about 90.degree. C., and
the reaction was quenched by the addition of a sodium carbonate
solution (about 5.8 g in 150 mL water). The water was then removed
from the reaction flask as follows: after heating the quenched
mixture to about 75-80.degree. C. and agitating the reaction flask
for about 10 minutes, the mixture was allowed to separate into
layers and the aqueous layer was drawn off. The reaction mixture
was then treated with an additional 150 mL of water, and the water
removal procedure was repeated.
[0057] The remaining reaction mixture was then charged to a tared
4-neck round bottom flask equipped with an agitator, a condenser
via a 3-way take-off adapter, a thermocouple assembly, and a sparge
tube. The reaction mixture was heated to about 245.degree. C. with
agitation under constant nitrogen sparge (at a rate of about 2000
mLlmin), with the solvent distilling off at about 140-170.degree.
C. Samples of the reaction mixture were extracted periodically (in
1-2 mL aliquots) under nitrogen purge, and analyzed for softening
point. The reaction was allowed to proceed under nitrogen sparge
until the desired softening point was reached. Then, the reaction
product was cooled and discharged, to afford an RP tackifier resin
with a softening point of 139.6.degree. C. and a Gardner color of
9.3 (neat).
EXAMPLES 3-4, 5C-8C, 9, 10 AND 11C
Adhesive Formulation and Testing
[0058] Contact cement compositions were prepared according to the
weight percentages indicated in Table 1. A reaction flask was
charged with chloroprene polymer, zinc oxide, antioxidant
(IRGANOX.TM. 1076 antioxidant from Ciba Specialty Chemicals,
Tarrytown N.Y. 10591 USA; www.cibasic.com was used, however other
antioxidants could alternatively be used), four-ninths of the
indicated amount of magnesium oxide, and toluene (about six times
the weight of polymer). The reaction mixture was then agitated
until all polymer was dissolved and the inorganic components were
dispersed. A separate reaction flask was charged with tackifier
resin, the remaining magnesium oxide, toluene (about twice the
weight of tackifier resin), and water (about one-ninth the total
amount of magnesium oxide), and mixed until the tackifier resin was
dissolved and the inorganic components were dispersed. The contents
of the two flasks were then combined and mixed until homogenous,
affording a contact cement composition.
[0059] Contact cement compositions were then tested for adhesive
strength. Prior to any coating the contact cements were agitated in
case any settling had occurred. Then, the contact cement
composition was applied to cotton canvas substrate using a hand
Acculab Drawdown Machine with a #20 wire wrapped rod. Each contact
cement sample was coated onto cotton canvas and allowed to dry at
ambient temperature. This process was repeated until a coating
thickness was obtained such that the weave of the fabric was no
longer visible on the surface of the adhesive film.
[0060] The coated sample substrates were allowed to cure for a week
at ambient temperature, before being heat-sealed to another sample
substrate coated with the same adhesive. Heat sealing was done with
a Carver Press (Carver, Inc., Wabash, Ind., USA;
www.carverpress.com) at 125.degree. C. and 89 psi, for five
minutes, and samples were then allowed to rest at ambient
temperature for five days. Then, after being cut into one-inch wide
strips, an Instron Model 1137 test instrument (Instron Corporation,
Canton Mass.; www.instron.com) was used to separate the sample
substrates from each other, in a t-peel format at a rate of 12
inches/min. The average force required to separate six inches of
the strips (i.e., peel) is indicated in Table 1.
[0061] For comparison purposes, two resins were selected. One was a
commercial product, TAMANOL.TM. 803L tackifier, which is commonly
used in contact cement formulations for footwear manufacture. The
other was a resin prepared using BF.sub.3 catalysis in lieu of
Bronsted acid catalysis. The data of Table 1 evidence the superior
performance properties of RP and RTP resins of the present
invention. Thus, in various optional aspects of the invention, the
RP or RTP resin provides a peel value (lb/in, measured as described
herein) of greater than 20, or greater than 21, or greater than 22,
or greater than 23, or greater than 24, or greater than 25, or
greater than 26, or greater than 27, or greater than 28, or greater
than 29, or greater than 30, or greater than 31, or greater than
32, or greater than 33, or greater than 34, or greater than 35, or
greater than 36, or greater than 37, or greater than 38, or greater
than 39, or greater than 40, or greater than 41, or greater than
42, or greater than 43, or greater than 44.
[0062] All of the above U.S. patents, U.S. patent application
publications, U.S. patent applications, foreign patents, foreign
patent applications and non-patent publications referred to in this
specification and/or listed in the Application Data Sheet, are
incorporated herein by reference, in their entirety.
[0063] From the foregoing it will be appreciated that, although
specific embodiments of the invention have been described herein
for purposes of illustration, various modifications may be made
without deviating from the spirit and scope of the invention.
Accordingly, the invention is not limited except as by the appended
claims. TABLE-US-00001 TABLE 1 Contact Cement Formulations and
Properties Ex. 3 Ex. 4 Ex. 5C Ex. 6C Ex. 7C Ex. 8C Ex. 9 Ex. 10 EX.
11C Component Weight Percent Chloroprene polymer 60.2 60.2 60.2
60.2 60.2 60.2 72.2 72.2 72.2 Tackifier resin 30.1 30.1 30.1 30.1
30.1 30.1 18.1 18.1 18.1 MgO 5.5 5.5 5.5 5,5 5.5 5,5 5.5 5.5 5.5
ZnO 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 IRGANOX .TM. 1076
antioxidant 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Tackifier type RP
resin RTP resin BF.sub.3- BF.sub.3- BF.sub.3- TAMANOL .TM. RP resin
RTP resin TAMANOL .TM. of Ex. 2 of Ex. 1 catalyzed catalyzed
catalyzed 803L of Ex. 2 of Ex. 1 803L Rosin:Phenol weight ratio 4:1
-- -- -- -- -- 4:1 -- -- Rosin:TP weight ratio -- 1:1 -- -- -- --
-- 1:1 -- Rosin/Terpene/Phenol -- -- 1:1:0.5 2:1:0.75 1:2:0.75 --
-- -- -- w/w Distribution % phenol in BF.sub.3-catalyzed -- -- 20
20 20 -- -- -- -- samples Peel (lb/in) 25.8 32.3 4.0 19.0 11.5 20.5
24.7 44.2 25.2
* * * * *
References