CURABLE RESIN COMPOSITION, METHOD FOR THE PREPARATION
THEREOF. AND ARTICLES DERIVED THEREFROM;
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent Application
Serial No. 60/176529, filed January 18, 2000.
BACKGROUND OF THE INVENTION
The present invention relates to curable resin compositions. In
particular, the invention relates to curable resin compositions exhibiting
reduced volume change on curing.
Thermosetting resins in general, and unsaturated polyester resins in
particular, are useful in a variety of applications, including structural
automotive parts, building and construction components, and boat hulls. In a
typical sheet molding compound (SMC) formulation, the unsaturated polyester
comprises only about 8 to 15% of the total formulation. Other components
include a crosslinking agent such as styrene monomer, fillers such as calcium
carbonate, glass fiber, thickeners, mold release agents, low profile additives,
initiators, co-promoters, and inhibitors. Unsaturated polyester resins may
exhibit excellent physical properties and solvent resistance, as well as good
weatherability.
Notwithstanding these advantages, the commercial adoption of
unsaturated polyester resins has been limited by a number of deficiencies,
including (1) poor surface appearance, including fiber patterns, (2) warpage of
molded parts, (3) difficulty molding to close tolerances, (4) internal cracks and
voids, particularly in thick sections, and (5) notable depressions (sink marks)
opposite reinforcing ribs and bosses. These deficiencies are thought to be
caused by the high polymerization shrinkage from the copolymerization of the
unsaturated polyester resin with the crosslinking agent. The shrinkage causes
the compound to pull away from the mold surface.
In a normal high-temperature-curing cycle, the liquid resin is heated to
temperatures in excess of 140°C, resulting in a thermally induced expansion.
As the unsaturated polyester resin begins to crosslink and the unsaturated
components become consumed there is a negative volume change due to the
density difference. Once reaction is complete, the system is cooled to ambient
condition, causing a further negative volume change. A neat polyester resin
will typically exhibit as much as a negative 7% volume change on high-
temperature curing.
Although many approaches have been taken to reduce curing shrinkage,
including changes in resin and co-monomer structures, use of large amounts of
filler, and even partial polymerization before molding, these approaches have
been inadequate. Another approach has been the addition of certain
thermoplastics to the formulation. These thermoplastics, when functioning in
such a role, are commonly referred to as low-profile additives (LPAs). Known
LP As include polymethyl methacrylates, vinyl chloride-vinyl acetate
copolymers, polyurethanes, and styrene-butadiene copolymers.
The generally accepted mechanism for shrinkage control relies on
induced strain relief through stress cracking of the separate LPA phase within
the thermoset matrix. Many known LPAs have a high molecular weight and
are polar in nature to improve compatibility with the uncured resin. During
curing (crosslinking), as the resin polarity decreases, the LPA is rejected from
the matrix and isolated as solid domains, t5rpically less than about 5
micrometers in size. These distinct LPA domains dispersed in the cured
thermoset matrix act as strain relief sites. Thus when the strain increases it can
induce preferential stress cracking through the weak thermoplastic phase, thus
relieving the strain, forming voids and compensating for the overall shrinkage.
However, in low temperature curing applications, known LPAs are not
as effective. Thus, there is a need for a shrinkage control and stress release
agent for low-temperature curing applications.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an image of molded unsaturated polyester resin (UPR) with
no low-profile additive (#3), with polyvinyl acetate (#1), and with a capped
poly(arylene ether) (#2). See Examples 1-6 and Comparative Examples 1-6.
Figure 2 is an image of molded UPR compositions comprising, from
lower right to upper left, 0, 2, 4, and 6 weight percent capped poly(arylene
ether). See Examples 8-13 and Comparative Example 11.
Figure 3 is an image of parts molded from a composition comprising an
unsaturated polyester, a capped poly(arylene ether), and varying levels of
curing catalyst and curing promoter. See Examples 14-21.
BRIEF SUMMARY OF THE INVENTION
The above-described and other drawbacks and disadvantages of the
prior art are alleviated by a curable resin composition, comprising:
an unsaturated polyester;
an alkenyl aromatic monomer; and
i^an amount of a capped poly(arylene ether) effective to reduce curing
shrinkage.
The present inventors have found capped poly(arylene ether)s are more
effective at reducing shrinkage and relieving stress than commercially available
LPAs.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A curable resin composition comprises:
an unsaturated polyester;
an alkenyl aromatic monomer; and
. an amount of a gapped poly(arylene ether) effective to reduce curing
shrinkage.
The composition comprises an unsaturated polyester. An unsaturated
polyester is generally obtained by reaction of at least one polyhydric alcohol
with at least one polybasic acid comprising an unsaturated polybasic acid.
Specific examples of unsaturated polybasic acids that may be used to
form the unsaturated polyester include maleic anhydride, maleic acid, fumaric
acid, itaconic acid, citraconic acid, chloromaleic acid, dimeric methacrylic acid,
nadic acid, tetrahydrophthalic acid, endo-methylenetetrahydrophthalic acid,
hexachloro-endo-methylenetetrahydrophthalic acid, halogenated phthalic
acids, and the like, as w^ell as their corresponding acids, esters, and anhydrides.
Preferred unsaturated acids include maleic acid, fumaric acid, and their esters
and anhydrides.
Often, polyfunctional saturated and aromatic acids are employed in
conjunction with the polybasic unsaturated acids to reduce the density of the
ethylenic unsaturation and provide the desired chemical and mechanical
properties to the coating. Examples of saturated and aromatic polybasic acids
include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid,
eicoic acid, phthalic acid, isophthalic acid, terephthalic acid, and the like, as
well as their esters and anhydrides. Preferred aromatic polybasic acids include
phthalic acid, isophthalic acid, and their esters and anhydrides.
Examples of polyhydric alcohols include ethylene glycol, propylene
glycol, diethylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol,
1,4-butanediol, neopentyl glycol, glycerol, triethylene glycol, pentanediol,
hexylene glycol, hydrogenated bisphenol A, bisphenol A-alkylene oxide
adducts, tetrabromobisphenol A-alkylene oxide adducts, and the like.
Preferred polyhydric alcohols include propylene glycol.
Unsaturated polyesters are commercially available, often as
compositions further comprising an alkenyl aromatic monomer, and include,
for example, the unsaturated polyester resins obtained from Ashland as
Ashland Q6585, and from Alpha Owens Corning as AOC-XV2346.
The composition may comprise the unsaturated polyester in an amount
of about 20 to about 80 parts, preferably about 30 to about 75 parts, more
preferably about 40 to about 70 parts, per 100 parts resin. Unless otherwise
specified, all parts are parts by weight.
In addition to the unsaturated polyester, the composition further
comprising an alkenyl aromatic monomer. The alkenyl aromatic monomer
may have the structure
wherein each R^ may be hydrogen, C1-C12 alkyl, or the like; each R^ may be
halogen, C1-C12 alkyl, C1-C12 alkoxyl, or the like; X is nitrogen or carbon; p is 1
to 4; and q is 0 to 5. When p=l, the alkenyl aromatic monomer is termed a
monofunctional alkenyl aromatic monomer; when p=2-4, the alkenyl aromatic
monomer is termed a polyfunctional alkenyl aromatic monomer. Suitable
alkenyl aromatic monomers include styrene, alpha-methylstyrene, alpha-
ethylstyrene, alpha-isopropylstyrene, alpha-tertiary-butylstyrene, alpha-
phenylstyrene, and the like; halogenated styrenes such as chlorostyrene,
dichlorostyrene, trichlorostyrene, bromostyrene, dibromostyrene,
tribromostyrene, fluorostyrene, difluorostyrene, trifluorostyrene,
tetrafluorostyrene, pentafluorostyrene, and the like; halogenated alkylstyrenes
such as chloromethylstyrene, and the like; alkoxystyrenes such as
methoxystyrene, ethoxystyrene, 1,3-divinylberuzene, 1,4-divinylbenzene,
trivinylbenzene, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, and the
like; vinylpyridine, 2,4-divinylpyridine, 2,5-divinylpyridine, 2,6-
divinylpyridine, 3,5-divinylpyridine, 2,4,6-trivinylpyridine, and the like; and
mixtures comprising at least one of the foregoing alkenyl aromatic monomers.
In the foregoing substituted styrenes for which no substituent position is
specified, the substituent may occupy any free position on the aromatic ring.
Preferred alkenyl aromatic monomers include styrene, alpha-
methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-t-
butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, 1,3-divinylbenzene, 1,4-
divinylbenzene, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, and the
like, and mixtures comprising at least one of the foregoing alkenyl aromatic
monomers. Preferred alkenyl aromatic monomers further include styrenes
having from 1 to 5 halogen substituents on the aromatic ring, and mixtures
comprising at least one such halogenated styrene.
The composition may comprise the alkenyl aromatic monomer in an
amount of about 10 to about 70 parts, preferably about 20 to about 60 parts,
more preferably about 30 to about 60 parts, per 100 parts resin.
In addition to the unsaturated polyester and the alkenyl aromatic
monomer, the curable resin composition comprises a capped poly(arylene
ether). A capped poly(arylene ether), is defined herein as a poly(aryIene ether)
in which at least 10%, preferably at least 50%, more preferably at least 7S%, yet
more preferably at least 90%, even more preferably at least 95%, of the free
hydroxyl groups present in the corresponding uncapped poly(arylene ether)
have been removed by reaction with a capping agent.
There is no particular limitation on the intrinsic viscosity of the capped
poly(arylene ether). The poly(arylene ether) may have an intrinsic viscosity of
about 0.05 to about 0.80, as measured in chloroform at 23°C. In a preferred
embodiment, the intrinsic viscosity may be about 0.08 to about 0.40 deciliters
per gram (dl/g), preferably about 0.10 to about 0.35 dl/g, more preferably
about 0.12 to about 0.31 dl/g. Generally, the intrinsic viscosity of the capped
poly(arylene ether) will vary insignificantly from the intrinsic viscosity of the
corresponding uncapped poly(arylene ether). It is expressly contemplated to
employ blends of at least two capped poly(arylene ether)s having different
molecular weights and intrinsic viscosities.
The capped poly(arylene ether) may be represented by the structure
Q-a-K)y
wherein Q is the residuum of a monohydric, dihydric, or polyhydric phenol,
preferably the residuum of a monohydric or dihydric phenol, more preferably
the residuum of a monohydric phenol; y is 1 to 100; J comprises recurring units
having the structure
wherein R^-R^ may be hydrogen, halogen, primary or secondary C1-C12 alkyl,
C1-C12 alkenyl, C1-C12 alkynyl, C1-C12 aminoalkyl, C1-C12 hydroxyalkyl, phenyl,
C1-C12 haloalkyl, C1-C12 aminoalkyl, C1-C12 hydrocarbonoxy, C1-C12
halohydrocarbonoxy wherein at least two carbon atoms separate the halogen
and oxygen atoms, or the like; m is 1 to about 200; and K is a capping group
produced by reaction of the phenolic hydroxyl groups on the poly(arylene
ether) with a capping reagent. The resulting capping group may be selected
from the group consisting of
wherein R^ may be C1-C12 alkyl, or the like; R^-R^o may be hydrogen, C1-C12
alkyl, C1-C12 alkenyl, C1-C12 aryl, C1-C12 mixed (alkyl-aryl), C1-C12
alkoxycarbonyl, C1-C12 aryloxycarbonyl, mixed (alkyl-aryl)oxycarbonyl, nitrile,
formyl, carboxylate, imidate, thiocarboxylate, or the like; R^^-Ri^ may be
hydrogen, halogen, C1-C12 alkyl, hydroxy, amino, or the like; and wherein Y is
a divalent group selected from the group consisting of
wherein R^^ and R^^ may be hydrogen, Ci-Cu alkyl, or the like.
In one embodiment, Q is the residuum of a phenol, including
polyfunctional phenols, and includes radicals of the structure
wherein R^-R^ may be hydrogen, halogen, primary or secondary C1-C12 alkyl,
C1-C12 alkenyl, C1-C12 alkynyl, C1-C12 aminoalkyl, C1-C12 hydroxyalkyl, phenyl,
C1-C12 haloalkyl, C1-C12 aminoalkyl, C1-C12 hydrocarbonoxy, C1-C12
halohydrocarbonoxy wherein at least two carbon atoms separate the halogen
and oxygen atoms, or the like; Z may be hydrogen, Cl-20 alkyl, aryl, mixed
alkyl-aryl hydrocarbons, such hydrocarbon groups containing a substituent
selected from the group consisting of carboxylic acid, aldehyde, alcohol, and
amino radicals, or the like; Z also may be sulfur, sulfonyl, sulfuryl, oxygen, or
other such bridging group having a valence of 2 or greater to result in various
bis- or higher polyphenols; n is 1 to about 100, preferably 1 to 3, and most
preferably 1 or 2.
In one embodiment, the capped poly(arylene ether) is produced by
capping an uncapped poly(arylene ether) consisting essentially of the
polymerization product of at least one monohydric phenol having the structure
wherein R-^-R^ may be hydrogen, halogen, primary or secondary C1-C12 alkyl,
C1-C12 alkenyl, C1-C12 alkynyl, C1-C12 aminoalkyl, C1-C12 hydroxyalkyl, phenyl,
C1-C12 haloalkyl, C1-C12 aminoalkyl, C1-C12 hydrocarbonoxy, C1-C12
halohydrocarbonoxy wherein at least two carbon atoms separate the halogen
and oxygen atoms, or the like. Suitable monohydric phenols include those
described in U.S. Patent No. 3,306,875 to Hay, and highly preferred
monohydric phenols include 2,6-dimethylphenol and 2,3,6-trimethylphenol.
In a preferred embodiment, the capped poly(arylene ether) comprises at
least one capping group having the structure
wherein R^-R^^ may be hydrogen, C1-C12 alkyl, C1-C12 alkenyl, C1-C12 aryl, Ci-
C12 mixed (alkyl-aryl), C1-C12 alkoxycarbonyl, C1-C12 aryloxycarbonyl, mixed
(alkyl-aryl)oxycarbonyl, nitrile, formyl, carboxylate, imidate, thiocarboxylate,
or the like. Highly preferred capping groups include acrylate
(R8=R9=Rio=hydrogen) and methacrylate (R8=methyl, R9=Rio=hydrogen).
In another preferred embodiment, the capped poly(arylene ether)
comprises at least one capping group having the structure
wherein R^ is C1-C12 alkyl, preferably C1-C6 alkyl, more preferably methyl or
isopropyl.
In yet another preferred embodiment, the capped poly(arylene ether)
comprises at least one capping group having the structure
wherein R"-Ri5 may be hydrogen, halogen, C1-C12 alkyl, hydroxy, amino, or
the like. Preferred capping groups of this type include salicylate (R^=hydroxy,
RiO-Ri3=hydrogen).
In a preferred embodiment, the capped poly(arylene ether) is
substantially free of amino substituents, including alkylamino and
dialkylamino substituents, wherein substantially free means that the capped
poly(arylene ether) contains less than about 300 micrograms, preferably less
than about 100 micrograms, of atomic nitrogen per gram of capped
poly(arylene ether). Although many poly(arylene ether)s are synthesized by
processes that result in the incorporation of amino substituents, the present
inventors have found that thermoset curing rates are increased when the
capped poly(arylene ether) is substantially free of amino substituents.
Poly(arylene ether)s substantially free of amino substituents may be
synthesized directly or generated by heating amino-substituted poly(arylene
ether)s to at least about 200°C.
There is no particular limitation on the method by which the capped
poly(arylene ether) is prepared. The capped poly(arylene ether) may be
formed by the reaction of an uncapped poly(arylene ether) with a capping
agent. Capping agents include compounds known in the literature to react
with phenolic groups. Such compoimds include both monomers and polymers
containing, for example, anhydride, acid chloride, epoxy, carbonate, ester,
isocyanate, cyanate ester, or alkyl halide radicals. Capping agents are not
limited to organic compounds as, for example, phosphorus and sulfur based
capping agents also are included. Examples of capping agents include, for
example, acetic anhydride, salicylic anhydride, polyesters comprising salicylate
units, homopolyesters of salicylic acid, acrylic anhydride, methacrylic
anhydride, glycidyl acrylate, glycidyl methacrylate, acetyl chloride, benzoyl
chloride, diphenyl carbonates such as di(4-nitrophenyl)carbonate, acryloyl
esters, methacryloyl esters, acetyl esters, phenyUsocyanate, 3-isopropenyl-
alpha,alpha-dimethylphenylisocyanate, cyanatobenzene, 2,2-bis(4-
cyanatophenyl)propane), 3-(alpha-chloromethyl)styrene, 4-(alpha-
chloromethyl)styrene, allyl bromide, and the like, carbonate and substituted
derivatives thereof, and mixtures thereof. These and other methods of forming
capped poly(arylene ether)s are described, for example, in U.S. Patent Nos.
3,375,228 to Holoch et al.; 4,148,843 to Goossens; 4,562,243, 4,663,402, 4,665,137,
and 5,091,480 to Percec et al.; 5,071,922, 5,079,268, 5,304,600, and 5,310,820 to
Nelissen et al.; 5,338,796 to Vianello et al.; and European Patent No. 261,574 Bl
to Peters et al.
In a preferred embodiment, the capped poly(arylene ether) may be
prepared by reaction of an uncapped poIy(arylene ether) with an anhydride in
the alkenyl aromatic monomer as solvent. This approach has the advantage of
generating the capped poly(aryIene ether) in a form that can be immediately
blended with other components to form a curable composition; using this
method, no isolation of the capped poly(arylene ether) or removal of unwanted
solvents or reagents is required.
A capping catalyst may be employed in the reaction of an uncapped
poly(arylene ether) with an anhydride. Examples of such compounds include
those known to the art that are capable of catalyzing condensation of phenols
with the capping agents described below. Useful materials are basic
compounds including, for example, basic compound hydroxide salts such as
sodium hydroxide, potassium hydroxide, tetraalkylammonium hydroxides,
and the like; tertiary alkyl amines such as tributyl amine, triethylamine,
dimethylbenzylamine, dimethylbutylamine and the like; tertiary mixed alkyl-
arylamines and substituted derivatives thereof such as dimethylaniline, and the
like; heterocyclic amines such as imidazoles, pyridines, and substituted
derivatives thereof such as 2-methylimidazole, 2-vinylimidazole, 4-
(dimethylamino)pyridine, 4-(pyrrolino)pyridine, 2-, 3-, or 4-vinylpyridine.
Also useful are organometallic salts such as, for example, tin and zinc salts
known to catalyze the condensation of, for example, isocyanates or cyanate
esters with phenols. The organometallic salts useful in this regard are known
to the art in numerous publications and patents well known to those skilled in
this art.
The composition may comprise a blend of at least two capped
poly(arylene ether)s. Such blends may be prepared from individually prepared
and isolated capped poly(arylene ether)s. Alternatively, such blends may be
prepared by reacting a single poly(arylene ether) with at least two capping
agents.
The capped poly(arylene ether) may be used an any amount effective to
reduce the curing shrinkage of the composition compared to the curing
shrinkage of the corresponding composition without the capped polyarylene
ether.
The curing shrinkage of a cured object comprising the composition may
be defined by the equation
wherein S is the curing shrinkage expressed as a percent, Lbefore is the length
before curing of a molded object comprising the composition, and La/ier is the
length after curing of a molded object comprising the composition. In a
preferred embodiment, the capped poly(arylene ether) is used in an amount
effective to produce shrinkage in any one dimension not greater than about 3%,
preferably not greater than about 2%, more preferably not greater than about
1%. In some cases the addition of the capped poly(arylene ether) may result in
expansion after curing, which leads to a negative value of S. In such cases, it is
preferred that the curing shrinkage not be less than about -3%, more preferably
not less than about -2%, yet more preferably not less than about -1%.
Shrinkage of the composition may be expressed relative to the shrinkage
of the corresponding composition without the capped poly(arylene ether).
Thus, shrinkage reduction may be defined by the equation
where SR is the shrinkage reduction expressed as a percentage, S+cappedPPE is the
curing shrinkage, as defined above, of a molded object comprising the
composition with the capped poly(arylene ether), and S-cappedPPE is the curing
shrinkage of a molded object comprising the corresponding composition
without the capped poly(arylene ether). It is preferred that the capped
poly(arylene ether) be used in an amount effective to produce a shrinkage
reduction of at least about 25%, preferably at least about 50%, more preferably
at least about 75%. In the instances in which the composition without capped
poly(arylene ether) exhibits curing shrinkage and the composition with capped
poly(arylene ether) exhibits curing expansion, the value of SR will exceed
100%. As it may sometimes be desirable for the composition to exhibit slight
expansion on curing, it is preferred that the capped poly(arylene ether) be used
in an amount effective to produce a shrinkage reduction not greater than about
150%, more preferably not greater than about 125%, yet more preferably not
greater than about 110%.
The effective amount of the capped poly(arylene ether) will depend on
the nature and amount of the unsaturated polyester, the nature and amount of
the alkenyl aromatic monomer, and the nature of the capped poly(arylene
ether), as well as the curing conditions. Generally, the composition may
comprise the capped poly(arylene ether) in an amount of about 0.1 to about 12
parts, preferably about 0.5 to about 10 parts, more preferably about 1 to about 8
parts, per 100 parts resin.
In addition to the components discussed above, the curable resin
composition may, optionally, further comprise a curing catalyst. Curing
catalysts, also referred to as initiators, are well known to the art and used to
initiate the polymerization, cure or crosslink any of numerous thermoplastics
and thermosets including unsaturated polyester, vinyl ester and allylic
thermosets. Non-limiting examples of curing catalysts are those described in
"Plastic Additives Handbook, 4* Edition" R. Gachter and H. MuUer (eds.), P.P.
Klemchuck (assoc. ed.) Hansen Publishers, New York 1993 and in U.S. Patent
Nos. 5,407,972 to Smith et al., and 5,218,030 to Katayose et al. The curing
catalyst for the unsaturated portion of the thermoset may include any
compound capable of producing radicals. Such curing catalysts may include
both peroxy and non-peroxy based radical initiators. Examples of peroxy
initiators useful in the present invention include, for example, benzoyl
peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, lauryl peroxide,
cyclohexanone peroxide, t-butyl hydroperoxide, t-butyl benzene
hydroperoxide, t-butyl peroctoate, 2,5-dimethylhexane-2,5-dihydroperoxide,
2,5-dimethyl-2,5-di(t-butylperoxy)-hex-3-yne, di-t-butylperoxide, t-butylcumyl
peroxide, aIpha,alpha'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-
2,5-di(t-butylperoxy)hexane, dicumylperoxide, di(t-butylperoxy isophthalate, t-
butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-
butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane,
di(trimethylsilyl)peroxide, trimethylsilylphenyltriphenylsilyl peroxide, and the
like, and mixtures comprising at least one of the foregoing curing agents.
Typical non-peroxy initiators include, for example, 2,3-dimethyl-2,3-
diphenylbutane, 2,3-trimethylsilyloxy-2,3-diphenylbutane, and the like, and
mixtures comprising at least one of the foregoing curing catalysts.
In a preferred embodiment, the curing catalyst may comprise t-butyl
peroxybenzoate and/or methyl ethyl ketone peroxide. The curing catalyst will
preferably promote curing at a temperature of about 0°C to about 200°C,
preferably about 20°C to about 50°C, more preferably about 25°C to about
40°C.
When present, the curing catalyst may be used in an amount of about 0.1
to about 10 parts, preferably about 0.2 to about 5 parts, more preferably about
0.5 to about 2 parts, per 100 parts resin.
The composition may, optionally, further comprise a curing promoter to
decrease the gel time. Suitable curing promoters include transition metal salts
and complexes such as cobalt naphthanate and cobalt ethylhexanoate; and
organic bases such as N,N-dimethylaniline (DMA) and N,N-diethylaniline
(DEA). In one embodiment, cobalt naphthanate and DMA are used in
combination. When present, the curing promoter may be used in an amount of
about 0.01 to about 1 parts, preferably about 0.02 to about 0.5 parts, more
preferably about 0.05 to about 0.2 parts, per 100 parts resin.
When the composition is to be cured using ultraviolet light, it may
further comprise a photoinitiator, such as, for example, the photoinitiators
described in U.S. Patent No. 5,407,972, including, for example, ethyl benzoin
ether, isopropyl benzoinether, butyl benzoin ether, isobutyl benzoin ether,
alpha,alpha-diethoxyacetophenone, alpha,alpha-dimethoxy-alpha-
phenylacetophenone, diethoxyphenylacetophenone, 4,4'-dicarboethoxybenzoin
ethylether, benzoin phenyl ether, alpha-methylbenzoin ethyl ether alpha-
methylolbenzoin methyl ether, trichloroacetophenone, and the like, and
mixtures comprising at least one of the foregoing photoinitiators.
The composition may further comprise additives known in the art,
including, for example, flame retardants, flame retardant synergists, mold
release agents and other lubricants, antioxidants, thermal stabilizers, ultraviolet
stabilizers, pigments, dyes, colorants, anti-static agents, fibrous reinforcements,
disc-shaped fillers, low-aspect ratio fillers, synthetic and/or natural resins
including thermoplastic elastomers, additional low profile additives, and the
like.
Flame retardant compounds include those known to the art as described
in numerous publications and patents known to those skilled in this art. Useful
in formulating flame retardant compositions are, for example, brominated
flame retardant compounds. Preferred brominated flame retardant
compounds include, for example, l,3,5-tris(2,4,6-tribromophenoxy)triazine,
polybrominated diphenyl ethers, poly(2,6-dibromophenylene ether),
brominated polystyrene, brominated cyclododecane, brominated bisphenol-A
diglycidyl ether, hydroxyethyl ether, Ci-ioo aromatic or mixed aromatic-
aliphatic phosphate esters such as triphenyl, tricresyl phosphate, tris(2-
allylphenylphosphate), tris{2-methoxy-4-allyIphosphate), tris(2-
propenylphenyl)phosphate, tris(4-vinylphenyl)phosphate
bis(diphenylphosphate ester)s of bisphenols such as bisphenol-A, resorcinol or
hydroquinone or the bis(diphenyl phosphoramide)s of diamines such as 1,6-
hexanediamine or piperidine, and alkylated or substituted derivatives
therefrom. If brominated flame retardants are used, it is preferred that the
bromine content of the brominated flame retardant be greater than 45%,
advantageously greater than 60%, and preferably greater than 70%. The high
bromine content of the flame retardant allows one to obtain UL-94 flammability
and at the same time maintaining high poly(arylene ether) content and optimal
dielectric properties.
Useful fillers and reinforcements include those known to the art known
to augment or modify the properties of plastics. Examples of such fillers well
known to the art include those described in "Plastic Additives Handbook, 4'^
Edition" R. Gachter and H. MuUer (eds.), P.P. Klemchuck (assoc. ed.) Hansen
Publishers, New York 1993. Non-limiting examples of fillers include silica
powder, such as fused silica and crystalline silica; boron-nitride powder and
boron-silicate powders for obtaining cured products having low dielectric
constant and low dielectric loss tangent; the above-mentioned powder as well
as alumina, and magnesium oxide (or magnesia) for high temperature
conductivity; and fillers, such as woUastonite including surface-treated
woUastonite, calcium sulfate (as its anhydride, dihydrate or trihydrate),
calcium carbonate including chalk, limestone, marble and synthetic,
precipitated calcium carbonates, generally in the form of a ground particulate
which often comprises 98+ weight % CaCOs with the remainder being other
inorganics such as magnesium carbonate, iron oxide and alumino-silicates;
surface-treated calcium carbonates; talc, including fibrous, modular, needle
shaped, or, preferably, lamellar talc; glass spheres, both hollow and solid, and
surface-treated glass spheres typically having coupling agents such as silane
coupling agents and/or containing a conductive coating; and kaolin, including
hard, soft, calcined kaolin, and kaolin comprising various coatings known to
the art to facilitate the dispersion in and compatibility with the thermoset resin;
mica, including metallized mica and mica surface treated with aminosilanes or
acryloylsilanes coatings to impart good physicals to compounded blends;
feldspar and nepheline syenite; silicate spheres; flue dust; cenospheres; fillite;
aluminosilicate (armospheres), including silanized and metallized
aluminosilicate; natural silica sand, quartz; quartzite; perlite; Tripoli;
diatomaceous earth; synthetic silica, including those with various silane
coatings, and the like.
The above fillers may be used in metallized or silane coated forms to
improve compatibility and adhesion with the thermoset blend.
Other mineral fillers include silicon carbide to increase the abrasive
action of polymers; molybdenum sulfide to improve the lubricity, zinc sulfide
to impart a white coloration; aluminum silicate (muUite), synthetic calcium
silicate and zirconium silicate to improve slip properties; barium titanate to
enhance dielectric properties; barium ferrite to produce magnetized polymers;
and barium sulfate and heavy spar.
Fillers also include metals and metal oxides, including particulate or
fibrous aluminum, bronze, zinc, copper, and nickel to improve, for example,
thermal, electrical conductivity or resistance to neutron or gamma rays.
Aluminum hydroxide may be incorporated to improve the flammability of a
polymer resin.
Fillers also include carbon, such as carbon black for use as a potential
colorant or to achieve improved volume conductivity (conductive carbon
black) and heat deflection temperature. Graphite, such as graphite powder
may be used to impart lubricity and/or conductivity to the formulation.
Fillers also include flaked fillers and reinforcements, such as glass flakes,
flaked silicon carbide, aluminum diboride, aluminum flakes, and steel flakes.
Fillers also include short inorganic fibers, including processed mineral
fibers such as those derived from blends comprising at least one of aluminum
silicates, aluminum oxides, magnesium oxides, and calcium sulfate
hemihydrate.
Fillers also include natural fillers and reinforcements, such as wood
flour obtained by pulverizing wood, and fibrous products such as cellulose,
cotton, sisal, jute, starch, cork flour, lignin, ground nut shells, com, rice grain
husks.
Fillers also include synthetic reinforcing fibers including polyesters such
as polyethylene terephthalate, polyvinylalcohol; and high tenacity fibers with
high thermal stability, including basalt fibers, carbon fibers, aromatic
polyamide fibers, polybenzimidazole, also polyimide fibers such as polyimide
2080 and PBZ fiber (both products of Dow Chemical Company, Midland,
Michigan USA), polyphenylene sulfide fiber, polyether ether ketone, boron-
fibers, ceramic fibers such as silicon carbide, and fibers from mixed oxides of
aluminum, boron and silicon sold under the trade name "Nextel" by 3M Co.,
St. Paul, MN, USA.
Fillers also include single crystal fibers or "whiskers", including silicon
carbide, alumina, boron carbide, carbon, iron, nickel, and copper.
Fillers also include electrically conductive polymers, such as
polypyrrole, polyaniline, polyphenylene, polyacetylene, and substituted
derivatives there of, including derivatives substituted with C1-C25 alkyl, C1-C25
alkoxy, C1-C25 alkylcarbonyl, C1-C25 alkylcarbonyloxy, C6-C25 aryl, C6-C25
aryloxy, C6-C25 arylcarbonyl, and C6-C25 arylcarbonyloxy.
Fillers also include fibers, including textile glass fibers such as E, A, C,
ECR, R, S, D, and NE glasses and quartz.
These aforementioned fillers may be added to the thermosetting resin
without any treatment, or after surface treatment, generally with an adhesion
promoter.
The formulation may also contain adhesion promoters to improve
adhesion of the thermosetting resin to the filler or to an external coating or
substrate. Also possible is treatment of the aforementioned inorganic fillers
may be treated with and adhesion promoter to improve adhesion. Adhesion
promoters include chromium complexes, silanes, titanates, zirco-aluminates,
propylene maleic anhydride copolymers, reactive cellulose esters and the like.
Chromium complexes include those once sold under the tradename VOLAN®
are included. Silanes include molecules having the general structure (RO)(4-
n)SiYn wherein n=l-3, R is an alkyl or aryl group and Y is a reactive functional
group which can enable formation of a bond with a polymer molecule.
Particularly useful examples of coupling agents are those having the structure
(RO)3SiY. Typical examples include vinyl-triethoxysilane, vinyl tris(2-
methoxy)silane, g-methacryloxypropyltrrmethoxy silane, g-
aminopropyltriethoxysilane, g-glycidoxypropyltrimethoxysilane, g-
mercaptopropyltrimethoxysilane. Titanates include those developed by S. J.
Monte et al. in Ann. Chem. Tech Conf. SPI (1980), Ann. Tech Conf. Reinforced
Plastics and Composite inst. SPI 1979, Section 16E, New Orleans; and S. J.
Monte, Mod. Plastics Int., volume 14 (1984), no. 6. pg. 2. Zirco-aluminates
include those described by L.B. Cohen in Plastics Engineering, volume 39,
(1983), no. 11, pg. 29. The adhesion promoter may be included in the
thermosetting resin itself, or coated onto any of the fillers described above to
improve adhesion between the filler and the thermosetting resin. For example
such promoters may be used to coat a silicate fiber or filler to improve adhesion
of the resin matrix.
Fillers may also include lubricants such as fatty alcohols and their
dicarboxylic acid esters including cetyl, stearyl and tall oil alcohol, distearyl
adipate, distearyl phthalate, fatty acid esters of glycerol and other short chain
alcohols including glycerol monooleate, glycerol monostearate, glycerol 12-
hydroxystearate, glycerol tristearate, trimethylol propane tristearate,
pentaerythritol tetrastearate, butyl stearate, isobutyl stearate, stearic acids, 12-
hydroxystearic acid, oleic acid amide, erucamide, bis(stearoyl)ethylene
diamine, calcium stearate, zinc stearate, neutral lead stearate, dibasic lead
stearate, stearic acid complex esters, oleic acid complex esters, calcium soap
containing complex esters, fatty alcohol fatty acid esters including isotridecyl
stearate, cetyl palmitate, stearyl stearate, behenyl behenate, montanic acid,
montanic acid ethylene glycol esters, montanic acid glycerol esters, montanic
acid pentaerythritol esters, calcium soap containing montanic acid esters,
calcium montanate, sodium montanate; linear or branched polyethylene,
partially saponified polyethylene wax, ethylene-vinyl acetate copolymer,
crystalline polyethylene wax; natural or synthetic paraffin including fully
refined wax, hardened paraffin wax, synthetic paraffin wax, microwax, and
liquid paraffin; fluoropolymers including polytetrafluoroethylene wax,
copolymers with vinylidene fluoride, and mixtures comprising at least one of
the foregoing lubricants.
Fillers may also include buckminsterfuUerenes, conductive carbon
fibers, vapor-grown carbon fibers, nanotubes, aerogels and xerogels. Preferred
vapor-grown carbon fibers include those having an average diameter of about
3.5 to about 500 nanometers as described in, for example, U.S. Patent Nos.
4,565,684 and 5,024,818 to Tibbetts et al.; 4,572,813 to Arakawa; 4,663,230 and
5,165,909 to Tennent; 4,816,289 to Komatsu et al.; 4,876,078 to Arakawa et al.;
5,589,152 to Tennent et al.; and 5,591,382 to Nahass et al.
Organic fillers such as thermoplastics and rubbers or elastomers may
also be used. Examples of thermoplastics include powdery engineering resins.
such as polycarbonate, thermoplastic polyester, polyestercarbonate,
polyphenylene ether, polysulfone, polyether sulfone, and polyacrylate;
powdery polyolefins, such as polyethylene, polypropylene and poly-4-methyl
pentene-1; fluoroplastics, such as polytetrafluoroethylene, tetrafluoroethylene-
propylene copolymer; chlorinated polyethylene; ethylene vinylacatate
copolymers; polyacrlyates such as polybutyl acrylate, poly(2-hexyl acrylate);
core-shell impact modifiers, such as polymethyhnethacrylate-
polybutylacrylate, poly(acrylonitrile-butadiene-styrene), poly(styrene-
acrylonitrile) copolymers, poly(methylmethacrylate-butadiene-styrene)
terpolymers; polyphenylene ether; ethylene propylene rubbers including diene
modified ethylene propylene rubbers, and butadiene/styrene block
copolymers.
Fillers may also include organic fillers such as rubbers, including
acrylate-butadiene rubber, copolymers of ethyl acrylate (or other acrylates) and
a small amount of a monomer that facilitates vulcanization (acrylic rubber),
terpolymer from tetrafluoroethylene, trifluoronitrosomethane, and nitroso-
perfluorobutyric acid (nitroso rubber), ethylacrylate-acrylonitrile copolymer
(acrylate rubber), alkylene sulfide rubber, urethane rubber based on polyester,
butadiene rubber (polybutadiene), bromobutyl rubber, chlorobutyl rubber,
polychlorotrifluoroethylene (fluoro rubber), chloropolyethylene,
epichlorohydrin homopolymer rubber (polychloromethytoxiran), chloroprene
rubber (polychloroprene), chlorosulfonylpolyethylene, ethylene-ethyl acrylate
copolymer (e.g., VAMAC®), copolymer of ethylene oxide (oxiran) and
chloromethyloxiran (epichlorohydrin rubber), epoxidized natural rubber,
ethylene-propylene-diene terpolymer, ethylene-propylene copolymer, urethane
rubber based on polyether, epichlorohydrin-ethyleneoxide terpolymer,
ethylene-vinylacetate copolymer, methyl silicone rubber with fluoro groups,
rubber having fluoro or fluoroalkyl or fluoroalkoxy substituent groups on the
polymer chain, copolymer from propylene oxide and ailyl glycidyl ether.
hydrogenated nitrile rubber, isobutylene-isoprene rubber (butyl rubber),
polyisobutene, synthetic isoprene rubber, liquid silicone rubber, methyl
silicone rubber, acrylonitrile-butadiene rubber, acrylonitrile-chloroprene
rubber acrylonitrile-isoprene rubber, isoprene rubber, polyglycol ether,
vinylpyridine-butadiene rubber, polyethylene, and methyl silicone rubber with
phenyl groups.
Fillers may also include polyfluoralkoxyphosphazene, polynorbomene,
propyleneoxide rubber, polypropylene, vinylpyridine-styrene-butadiene
rubber, urethane rubbers, methyl silicone rubber with phenyl and vinyl
groups, styrene-butadiene rubber, styrene-butadiene-styrene block copolymer
(thermoplastic elastomer), styrene-chloroprene rubber, polysiloxane treated
EPDM, styrene-isoprene rubber, styrene-isoprene-styrene block copolymer
(thermoplastic elastomer), polythioglycol ether, tetrafluoroethylene,
polysulfide rubbers, trans-polyoctenamer, trans-polypentenamer,
thermoplastic elastomers, thermoplastic polyolefins, thermoplastic
polyurethanes, methyl silicone rubber with vinyl groups, crosslinkable
polyethylene, emulsion polymer, solution polymer, oil-extended rubber,
poly(vinylchloride-co-vinyl acetate-co acrylic acid), poly(ethylene-co-
vinylacetate-co-acrylic acid).
Fillers may also include blowing agents such as azo compounds like
diazoaminobenzene, azobisisobutyronitrile, azodicarbonamide, azodicarbonic
acid, benzene sulfonyl hydrazide, benzene-l,3-disulfonylhydrazide,
diphenyloxide-4,4'-disulfonylhydrazide, p-toluenesulfonic acid hydrazide,
N,N'dinitrosopentamethylenetetraamine, N,N-dimethyl-N,N'-
dinitrosophthalamide, and sodium carbonate blends with acidic compounds
such as tartaric acid.
In a preferred embodiment, the curable resin composition comprises
about 30 to about 70 parts of an unsaturated polyester; about 15 to about 50
parts of an alkenyl aromatic monomer; and about 0.1 to about 12 parts of a
capped poly(arylene ether); wherein all amounts are based on 100 parts resin.
In a highly preferred embodiment, the composition comprises about 30
to about 70 parts of an unsaturated polyester; about 15 to about 50 parts
styrene; about 1 to about 8 parts of a capped poly(arylene ether) having an
intrinsic viscosity of about 0.10 to about 0.35 dL/g; about 0.1 to about 4 parts
of a curing catalyst; and about 0.01 to about 1 parts of a curing promoter;
wherein all amounts are based on 100 parts resin.
It will be understood that the invention includes uncured, partially
cured, and fully cured compositions.
There is no particular limitation on the methods by which the curable
resins are processed. Suitable methods include, for example, hand lay-up and
spray lay-up, casting, sheet molding, bulk molding, injection molding,
pultrusion, vacuum impregnation, and the like.
There is no particular limitation on the method by which the
composition may be cured. The composition may, for example, be cured
thermally or by using irradiation techniques, including UV irradiation and
electron beam irradiation.
In a preferred embodiment, the composition is suitable for low-
temperature curing. For example, the composition may be cured under
conditions comprising a curing temperature not greater than about 50°C
(preferably not greater than about 40°C, more preferably not greater than about
30°C) and a curing time not greater than about 5 hours (preferably not greater
than about 1 hour, more preferably not greater than about 30 min). A cured
composition will preferably exhibit a Barcol surface hardness measured
according to ASTM D2583 of at least about 30, more preferably at least about
40.
The invention is further illustrated by the following non-limiting
examples.
EXAMPLES 1-6, COMPARATIVE EXAMPLES 1-6
The unsaturated polyester resin system used in these examples was the
proprietary resin obtained from Ashland as Q6585. It is described by its
manufacturer as "high-reactivity, thickenable, polyester resin for use in low
profile and controlled shrink applications." The datasheet supplied with the
material indicates a styrene content of 35 weight percent. In Examples 1-6, the
LPA was a capped poly(arylene ether). Specifically, the capped poly(arylene
ether)s were methacrylate-capped poly(2,6-dimethylphenyl ether)s (PPE-MAA)
having intrinsic viscosities of 0.12 and 0.31 dl/g as measured in chloroform at
23°C. The capped poly(arylene ether)s were prepared by reaction of the
corresponding uncapped polyarylene ethers with methacrylic anhydride, using
procedures described in U.S. Patent Application Serial No. 09/440,747, filed
November 16, 1999. A commercial LPA containing a polyvinyl acetate,
obtained as LP-40A from Union Carbide, was used as comparison. The
initiator package was mixture of the curing catalyst methylethyl ketone
peroxide (MEKP) and the curing promoter cobalt ethylhexanote.
The compounding was conducted as follows. Styrene was weighed into
a disposable beaker and to this was added the LPA. In the case of PPE-MAA,
the mixture was then heated briefly (less than 10 minutes) on a water bath at
about 60°C with hand mixing until complete dissolution was achieved. To this
mixture was then added the Q6585 resin. Once mixed thoroughly, the curing
catalyst, MEKP, was added using a calibrated syringe. When the resulting
mixture was sufficiently mixed, the curing promoter was then added, again
using a calibrated syringe. The individual mixtures were then poured into
molds and placed in an air convection oven set at 35°C.
The onset of gelling occurred within the range of one half to two hours,
each with a substantial exotherm, after which the parts appeared hard and
cured. Generally, samples containing the PPE-MAA cured in short times, and
those without PPE-MAA took longer. The molds were then taken from the
oven and allowed to cool to ambient conditions. The samples were allowed to
sit for 24 hours before their final length was measured. The percent shrinkage
was calculated by comparing the initial length to the final length, where the
initial length is the length of the mold, and the final length is the length of the
molded bar after curing and 24 hours at ambient conditions.
The results are presented in Table 1 and show that the compositions of
Examples 1-6, with a capped poly(arylene ether), exhibit reduced shrinkage
compared to compositions with polyvinyl acetate and those with no LPA. As
shown in Figure 1, compositions of the invention also exhibit reduced
brittleness. In particular, the sample labeled #2 ("UPR + 4% Unsat.-PPE"),
corresponding to Example 1 of Table 1, is uncracked, whereas the samples
labeled #1 ("UPR + 4% PVA") and #3 ("UPR neat"), corresponding to
Comparative Examples 1 and 2, respectively, of Table 1, exhibit multiple cracks
and fractures.
EXAMPLE 7, COMPARATIVE EXAMPLES 7-10
Using the procedures described above, seven samples containing the
vinsaturated polyester resin Ashland Q6585 were prepared with variations in
poly(arylene ether) capping (none or methacrylate cap), intrinsic viscosity (0.12,
0.25, or 0.31 dL/g), and amount. All samples were cured for 16 hours at 35°C.
The results are presented in Table 2 and show that Example 8, with a
methacrylate-capped poly(arylene ether), cured more rapidly than
compositions with uncapped poly(arylene ether)s or with no LPA.
EXAMPLES 8-13, COMPARATIVE EXAMPLE 11
Seven samples were prepared with variations in capped poly(arylene
ether) intrinsic viscosity and amount. The unsaturated polyester resin (UPR)
used in these samples was a proprietary resin obtained from Alpha Owens
Coming as AOC XV2346, which is described by its manufacturer as containing
40-60% styrene and 40-60% solids. The capped poly(arylene ether)s were
methacrylate-capped poly(2,6-dunethylphenyl ether)s having intrinsic
viscosities of 0.12 and 0.31 dL/g, prepared according to the procedure
referenced above. For all samples, the curing promoter was cobalt
naphthanate. All samples were cured for about 24 24hours at 25°C. The
compositions and curing shrinkage results are presented in Table 3. The results
indicate that a moderate amount (2% or 4%) of either capped poly(arylene
ether) reduced curing shrinkage, while higher amounts caused expansion.
Figure 2 shows images of four of the molded compositions comprising capped
poly(arylene ether) having an intrinsic viscosity of 0.12 dL/g, sample labels in
the figure corresponding to example numbers as follows: 1 = C. Ex. 11; 2 = Ex.
8; 3 = Ex. 9; 4 = Ex. 10. The figure shows that the sample labeled (1),
corresponding to C. Ex. 11 with no added capped poly(arylene ether), exhibited
shrinkage, whereas the sample labeled (2), corresponding to Ex. 8 with 2
weight percent m.ethacrylate-capped poly(arylene ether) having an intrinsic
viscosity of 0.12 dL/g, exhibited reduced shrinkage; Exs. 9 and 10, with 4
weight percent and 6 weight percent methacrylate-capped poly(arylene ether),
respectively, exhibited expansion.
The components used for Examples 8-13 and Comparative Example 12-
11 were used to study the effect of curing catalyst and curing promoter
amount.
Compositions, curing conditions, and shrinkage results for eight
compositions are presented in Table 4. The results show that the capped
poly(arylene ether)s provide faster curing that can be used to reduce the
amount of curing catalyst and curing promoter at a given curing time.
Images of the eight molded parts, after curing, are provided in Figure 3.
The parts correspond, left to right, to Examples 14-21 in Table 4.
While the invention has been described with reference to preferred
embodiments, it will be understood by those skilled in the art that Various >
^changes may be mad^and equivalents may be substituted for elements thereof
without departing from the scope of the invention. In addition, many
modifications may be made to adapt a particular situation or material to the
teachings of the invention without departing from essential scope thereof.
Therefore, it is intended that the invention not be limited to the particular
embodiment disclosed as the best mode contemplated for carrying out this
invention, but that the invention will include all embodiments falling within
the scope of the appended claims.
All cited patents and other references are incorporated herein by ) ^^^ \y^
reference in their entirety. '^ 0 / j
WE CLAIM:
i. A curable resin coo^poaitiofi comfMrisii^:
20 to 80 parts of an unsaturated polyester such as hn'ein described, per 100 parts
resin;
10 to 70 parts of m alkenyl aromatic monomer such as Iwrein d^Karibed, per 100
parts resin; and
0.1 to 12 parts of a cq^d poly(arylene etfier) such as herein desoibed, par 100
parts resin, effective to reduce curing sbink^ge.
2. The curable resin conq>osition as claimed in claim U w'herein die unsaturated
polyester is the reaction product of at least one polyfaydric alcohol with al leaat one
polybasic acid compriaiqg an unsatairaied polybasic acid.
3. The curable resin coo^osition as claimed in claim 2, wherein the unsaturated
opolj^asic acid is selected from the grom> consistii^ of maleic acid, fimnric
acid, itaconic acid, citracOBitif» as claimed in claim 2 wherein the polyfaydric
alchettol A, bti^rfiettol A-allgrlene oxide
adducts, tetnbromobimrfmiol A-all^Iew oxide addiicls> and mixtures compriiiiig at
least one of fi^ foregoJAg polj^iydric alcoliolg.
5. The curable nwin coiqNwition as claimed in claim 2, wherein flie polybasic acid
fiirther compriaes a sfliurated or aromatic poh^baaic acid selected from the group
cooaiatitig of succinic acid, adipic acid, sebacic acid, azelaic acid, dodecaoedioic acid,
eiocic acid, phOulic acid, isqrfidialic acid, tn-q)fattialic acid, 4ie corFeBp 2>4-divH9ipyridine>
2,5-divinylpyridine, 2,6-diviiiyIpyridine, 3^-diviiiyIpyndine, 2, 4,6-
trivioy^iyrtdtne^ nd mixtures compristqg at least one of die fi)regoiqg alkenyl
aromatic mooomera.___________________._________________—^
-ifr The curable resin composition of Claim 1, wherein the capped
poly(arylene ether) has the structure
Q-a-K)y
wherein Q is the residuum of a monohydric, dihydric, or polyhydric phenol; y
is 1 to 100; J comprises recurring units having the structure
wherein R^-R^ are each independently selected from the group consisting of
hydrogen, halogen, primary or secondary C1-C12 alkyl, C1-C12 alkenyl, Ci-Ci2
alkynyl, C1-C12 aminoalkyl, C1-C12 hydroxyalkyl, phenyl, C1-C12 haloalkyl, Ci-
C12 aminoalkyl, C1-C12 hydrocarbonoxy, and Ci-Ci2 halohydrocarbonoxy,
wherein at least two carbon atoms separate the h&logen and oxygen atoms; m
is 1 to about 200; and K is a capping group selected from the group consisting
of
wherein R^ is C1-C12 alkyl; R^-Rio are each independently selected from the
group consisting of hydrogen, C1-C12 alkyl, C1-C12 alkenyl, C1-C12 aryl, C1-C12
mixed (alkyl-aryl), C1-C12 alkoxycarbonyl, C1-C12 aryloxycarbonyl, mixed
(alkyl-aryl)oxycarbonyl, nitrile, formyl, carboxylate, imidate, and
tfu'ocartKHiylato; R^H'^ are each independentlsr selected frmn (he groiv consistinig of
hydrogen, halogen, CpCij all^l, faydroi^, and mino; and wherem Y is a dhmleii
group seleded from the groxxp consiating of
wherein R^^ and r'^ are each independeody selected from tfie gnnip coiuisting of
hydrogen and Cj-Cu alkyt.
10. Thv curable nwin ctxnpoaitim w claimed in claim 11 wl^in Q is tfie residuum
of a mondq^dric phenol..
11. The curable reain oompoaition as claimed in claim 1, wdierein Ihe capped
poly(ai[yl«ic> edm*) comprises a cappiiq; ff^fop haviiq; ft» sirocture
wherein R'-R'^ are each independently selected from ttie group cooristing of
hydrogen, Ci-Ci3 a%l, Cj-Cu alkenyt,C]-Ci3 aryl, Cj-Cu mixed (att^l-aiyl), Q-Cia
alkoxycarbonyl, Cj-Cu aryloxycarbonyl, mixed (allcyl-aryl)oxycarbof^l, nifarile,
foiiiiyi> carboi^late, imidato, and tfiiocarboxylato.
12. Hw cunbie rrain compwitim as claimMl in claim 1, ^Mvin tiie capped
poly(Brylei>e ether) has an intrinsic viscosity of 0.08 to 0.40 deciliters per gram, as
measured in diloroform at 23*^0
13. The curable reain composition as claimed in claim 1, M^wrein the capped
poly(arylene elber) is substantially free of amino subatituents.
14. Hie curable resin conpositioa aa claimed in claim 1, fthlier compriaing a curing
catalyst
13. Hie curable reain composition as claimed in claim 17, comprisiiis not greatn* tfun
l.S parts of the curiqg catalyst per 100 parts resin.
16. llw cundble resin composition as claimed in claim 1 fivtim' conqinsiiig a
curing proDiioter. -"¦"——¦______.._________
Sff! The curable resin composition of Claim 19, comprising not greater
than .^^t 0.2 parts of the curing promoter per 100 parts resin.
2T. The curable resin composition of Claim 16, wherein the curing
catalyst is selected from the group consisting of benzoyl peroxide, dicumyl
peroxide, methyl ethyl ketone peroxide, lauryl peroxide, cyclohexanone
peroxide, t-butyl hydroperoxide, t-butyl benzene hydroperoxide, t-butyl
peroctoate, 2,5-dimethyIhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-
butylperoxy)-hex-3-yne, di-t-butylperoxide, t-butylcumyl peroxide,
alpha,alpha'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-
butylperoxy)hexane, dicumylperoxide, di(t-butylperoxy isophthalate, t-
butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-
butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane,
di(trimethylsilyl)peroxide, trimethylsilylphenyltriphenylsilyl peroxide, 2,3-
dimethyl-2,3-diphenylbutane, 2,3-trimethylsilyloxy-2,3-diphenylbutane, and
mixtures comprising at least one of the foregoing curing catalysts.
42r The curable resin composition of Claim 1, further comprising at
least one curing promoter.
'53r' The curable resin composition of Claim 1, wherein the curing
promoter is selected from the group consisting of cobalt naphthanate, cobalt
ethylhexanoate, N,N-dimethylaniline, N,N-diethylaniline, and mixtures
comprising at least one of the foregoing curing promoters.
21. Tlie curable nefin composition w claimed in claim 1» dfivtbnr c(»nprifii« at least
out additive selected from ttie group conaistiiiig of flame retBrdants, flatne retar&nt
syoerf^tta^ mold release agaota and otfier lirfmcsots, antioxidaate, Ifanrmal stsbilizers,
ultraviolet Btabiltjgers» pijpueutv, dyes colorants^ anti-static agrats, fibrous
reinforcements, diM-ahaped fillers, low-ai|>ect ratio fillers, agndietic resins, natural
resins and tfaermt^laatic eiagtonaca.
22. The curable resin ooii4>osti(»i as claimed in claim 1, wiiMvin die amoort of
tibe capped poIy(ar^ene etfwr) is eflN»ctive to reduce flie curipg dirinki^ge in any me
dtmenatott by si. lemit 25% conq>ared to the shrinkage of a corre^Mnding composition
without the vwpp^d poly(aiytene etfier).
I 23.^ Tbe curable resin conposition as claimed in claim 1, exhibiting a curiiig
— Arixkagt in any one dimension not greater flian 3.09i; wiierein curing
sduiflkage is d^aedby die equation
wherein S is the cirii^ dariolc^ expressed as a perceat, Lmp,, is die leog^ before
curing of a molded object cmniHiBing (he compositioD, and L^ut is the leugfh afler cu
flag of a molded object cooprisiiig die coniposition.
24. Tht curable resin compostiMi as claimed in claim 1, wherein the composition is
curable under conditimiB coavrisine a coring teiq>eratare not greater than SO'C
and a curiog time not greater Ihan 30 hours.
25. A curable resin cmnpoeHoBy cotaffneiag:
30 to 70 parte of an unsaturated polyester;
15 to SO parte of an alkenyl arMuatic mooomer, and
0.1 to 12 parte of a capped poly(arylene ether);
w4ierein all amounls are based on 100 parte resin.
26. A curable resin conq>oBition» cped poly( aiylene ether) effective to reduce the volume
change that acc