CA2097330A1 - Thermosetting polyester plastic compositions containing blocked polyisocyanate and isocyante-reactive material - Google Patents

Abstract

Abstract of the Disclosure A thermosetting molding composition which affords molded products having improved strength and surface smoothness, a method for making the same, and products made with the composition. The composition includes a) an unsaturated polyester resin; an olefinically unsaturated monomer; a thermoplastic low profile additive; a reinforcing filler; and additionally includes a blocked polyisocyanate and an isocyanate-reactive material different from the unsaturated polyester resin.

Description

THERMOSETTING POLYESTER PLASTIC COMPOSITIQNS
CONTAINING BLOC~ED POLYISOCYANATE_~ND
ISOCYANATE-RE~CTIvE ~A~ERIA~

This application is a ~ontinuation-in-part of Application Serial No. 07/767,998 filed September 3~, 1991.

Field of ~he Inven~io~
This application relates to reinforced thermosetting polyester compositions, and more particularly, to such compositions containing blocked polyisocyanates plus isocyanate-reactive material.

~ack~round of the Invention Re;nforced thermosetting polyester-based molding compositions in the form of sheet molding compound (SMC) and bulk molding compound (BMC~ have been known for many years. These materials are based on unsaturated polyester resins produced from a reaction between a polyol having at least 2 hydro~yl groups, and a mi~ture of saturated and unsaturated dicarbo~ylic acids (or their anhydrid~s). The initially formed unsaturated polyester resin is blended with one or more monomers capable of crosslinking with the unsaturated in the polyester, a pero~ide catalyst, and a reinforcing material such as fiberglass, then heated to decompose the pero~ide and ~ause the crosslinking reaction between the monomer and the unsaturation in the polyester molecule to occur. The resulting product is a composite of the reinforcing material and the crosslinked polyester.

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For many applications, an alkaline earth-containing thickener such as magnesium o~ide is added to the composition before crosslinking is initiated. This is thought to comple~ with residual carbo~yl groups of the polyester molecules, thereby increasing the ~iscosity of the mi~ture and aiding achievement of uniform distribution of reinforcing filler as the mi~ture is caused to flow into its final shape during processing. In addition to the materials mentioned thus far, the molding compositions also frequently contain various other fillers, mold release agent, and other additives to be discussed below.
A great variety of properties may be achieved in the cured composite by appropriate selection of the identities and amounts of the starting diacids, polyols, crosslinking monomers, catalysts, other additives, etc. used in the preparation. As a result, these materials have wide applicability in the manufacture of strong relatively light weight plastic parts.
Historically, molding composite materials based on thermosetting polyester resins suffered from ~he difficulties that 1) the surfaces of molded parts were poor, and included fiber patterns which required costly sanding operations for painted applications and precluded use of such materials in high appearance internally pigmented applications; -2~ parts could not be molded to close tolerances because of warpage; 3) molded parts contained internal cracks and voids, particularly in thick sections; and 4) molded parts had notable depressions or ~sinks" on surfaces opposite reinforcing ribs and bosses.

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The cause of these problems was believed to be a high degree of shrinkage during copolymerization of the unsaturated polyester ~esin with the crosslinking monomer. Such shrinkage during the crosslinking react;on causes the polymer to pull away from the surfaces of the mold and the fiberous reinforcements. This reduces accuracy of mold surface reproduction and leaves fiber patterns at the surface of the molded parts. ~he stresses creat~d by nonuniform shrinkage cause warpage, internal cracks, and poor reproduction of mold dimensions in finished molded parts. It has been shown that curing of typical unsaturated polyester resin results in volumetric shrinkage of appro~imately 7%.
The abo~e-discussed difficulties have been addressed in practice by adding certain thermoplastic material~ to the molding composite.
The presence of these therm~plastics in the composition reduces shrinkage of the part during curet or in some cases causes a small amount of e~pansion, thereby providing molded parts which ~ore accurately reflect the molds in which they were made, and which have relatively smooth surfaces.
The surface smoothness of a molded part is gauged by measuring its surface profile by means of a suita~le surface analyzer. A rough surface e~hibits a high surface profile, while a smooth surface e~hibits a low surface profile. As the addition of thermoplasti~ materials to the polyester-based molding composite results in smoother surfaces in the molded part, relative to ,, .
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- q -~he case wit~out such thermoplastic materials present, these thermoplastics are called "low prof i le additives".
A number of thermoplastics have been found to give var~ing levels of shrinkage control.
E~amples are:
a) poly(vinyl acetates). See, for example, US Patents 3,718,714; 4,284,736;
4,288,571; and 3,842,142.
b) polymethylmetha~rylates and copolymers with other acrylates. See, for ezample, US Patents 3,701,748; 3,722,241; 4,463,1S8; 4,D2D,036; and --~,161,471.
c) copolymers of vinyl chloride and vinyl acetate. ~ee, for e~ample, US Patents 9,28~,736 and 3,721,642.
d) polyurethanes. See, for example, US
Patents 4,035,439 and 4,463,158; British Patent 1,451,737; and European Patent 074,746.
e~ styrene-~utadiene copolymers and other elasto~ers. See, for e~ample, VS Patents 4,D42,036;
9,161,471; and 4,160,7S9.
f) ~olystyrene and certain copolymers of certain monomers. See, for e~ample, ~S Patents 3,503,921 and 3,674,893; Netherlands Patent 7~-15~86; and ~erman Patent 2,2~2,972.
9~ polycaprolactones. See, for egample, US Patents 3,~49,586 and 3,688,178.
h) cellulose acetate butyrate. See, for e~ample, US Patent 3,642,672.
i) saturated polyesters and various blends of saturated poly~sters with poly(~inyl chloride).

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See, for e~ample, VS Patents 3,989,707; 3,736,728;
and 4,263,199; Japanese Patent 4,601,783; and Netherlands Patent 70-14~68.
These polymers, when blended in appropriate ratios with unsaturated polyester resins and comonomers result in shrinkage control under both standard compression and injection molding conditions. For optimum shrinkage control and hence mold reproduction in particular systems, the combinations of structures and molecular weights of the unsaturated polyester resin and the thermoplastic low profile additive are selected on the basis of simple trials.
A wide variety of unsaturated polyester resin structures has been reported in the literature. The most eommonly used polyester resins, however, are those based on the condensation of 1.0 mole o~ maleic anhydride with a slight e~cess of propylene glycol, and similar resins in which up to 0.35 moles o~ the maleic anhydride is replaced with orthophthalic anhydride or isophthalic acid.
The comonomer is almost always styrene.
This approach to shrinkage control can also be applied in the case of vinyl ester resins. See for e~ample, US Patent 3,674,893.
Progress in overcoming the above-discussed problems of shrinkage of molded polyester-based composite material during cure has occurred in stages over appro~imately the past twenty-five years. The successive improvements have been quantified by determining the linear shrinkage of parts and/or measuring their surface smoothness.

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The first generation of low profile additives were materials such as polystyrene and polyethylene. Molded parts incorporating such additives were found to e~hibit shrinkage of sbout 2 mils per inch (0.2%), in contrast to shrinkages of 4 to ~ mils per inch (0.9-0.~%) found for composites lacking these additives. The resulting composites were found to accept internal pigments well, but the surface quality of the parts was poor and the dPgree of shrinkage, although improved relative to that of composites containing no low profile additive, was still objectionably high for many applications.
The second generation of low profile additives were acrylic-based polymers such as polymethylmethacrylate, which when employed with specific unsaturated polyester resins prepared by condensation ~f maleic anhydride with propylene glycol, gave composite materials which eghibited shrinkage of about 0.5 mils per inch (0.0~%). These materials were found to have poor pigmentability and poor surface smoothness by current standards.
The third generation of low profile additives were the poly(vinyl acetate) polymers.
Such additives can be used in a wide range of unsaturated polyester resin materials, and the molded parts e~hibit essentially no shrinkage.
Compositions containing poly(vinyl acetate) low profile additives have poor pigmentability, but the molded parts have very good dimensional stability and surface smoothness. As a result, these materials are widely used.

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The fourth generation of low profile additives are materials which cause unsaturated polyester resin composite materials containing them to tend to e~pand slightly during cure, thereby reproducing the surface of the mold with great accuracy. At room temperature, products made with these additives generally are 0.3 to 0.~ mils per inch larger than the room temperature dimensions of the ~old. The surface smoothness of parts made with these low profile additives equals or e~ceeds the smoothness of automotive grade steel.
There are several varieties of fourth generation low profile additives-1) a poly(vinyl acetate) or otherthermoplastic polymer, plus at least one shrinkage control "synergist'~. E~amples of shrinkage control synergists are a) epoxide-containing materials such as epo~idized octyl tallate, b~ secondary monomers such as vinyl acetate monomer, which are more reactive with themsel~es than with styrene, c) mi~tures of such epo~ides and secondary monomers, d) lactones such as caprolactone, e) silo~ane-alkylene o~ide polymers, and f) fatty acid esters.
2) certain modified poly~vinyl acetate) poly~ers which are employed with ~pecially selected unsaturated polyester resins.
3) a standard low profile additive such as poly(vinyl acetate), preferably acid-containing, plus an isocyanate prepol~mer resulting from reaction of a polyether polyol and a diisocyanate, which provides a dual thickening mechanism.

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Despite the substantial improvements in physical properties whi~h have been achieved in reinforced polyester-~ased composite material~ by use of low profile additives, further improvement in properties such as fle~ural strength, impact strength, and surface smoothness are still very desirable. Additives providing one or more of these improvements are ~he subject of the present application.
SummarY
It has been found that addition of a blocked polyisocyanate and an isocyanate-reactive material to a thermosetting polyester-based molding composition containing a low profile additive results iD final molded parts having significantly enhanced strength, particularly fle~ strength, as well as well as e~cellent shrinkage control and superior surface smoothness, relative to parts made from such polyester-based molding compositions not ~ .
containing these additives.
The thermosetting molding composition of the invention comprises an unsaturated polyester, an olefinically unsaturated monomer, a thermoplastic low profile additive, a reinforcing filler, and further includes a blocked polyisocyanate, and an isocyanate-reactive material which is different from the unsaturated polyester employed in the composition. An e~ample is a material which contains active hydrogen atoms, such as a polyol.
A process for preparing a reinforced thermoset molded composite includes the steps of preparing the thermosetting molding composition of ..

, , _ g _ the invention, forming this composition into a desired shape, and heating the shaped co~position to cure it.
Molded articles made usiny the composition and process of the invention are also aspects of the invention.

Detailed Desc~i~tion The unsaturated polyesters which are employed in the invention are materials which are well known to the art. Each is the reaction product of a polyol and at least one olefinically unsaturated dicarboxylic acid or anhydride, and may also include residues of saturated and/or aromatic dicarbo~ylic acids or anhydrides. The olefinic unsaturation is prefera~ly in the B position relative to at least one of the carbonyl groups of the dicarboxylic acid or anhydride. The unsaturated polyester typically has a molecular weight in the range of 1,00~ to 2,00~, and contains residual carboxyl and hydro~yl groups as well as olefinic unsaturation.
E~amples of suitable unsaturated dicarboxcyclic acids and anhydrides useful in preparation of the polyesters are materials such as mal~ic acid or anhydride, fumaric acid, tetrahydrophthalic acid or anhydride, hexachloroendomethylene tetrahydrophthalic anhydride :
(nchlorendic anhydriden), itaconic acid, citraconic acid, mesaconic acid, and Diels Alder adducts of maleic acid or anhydride with compounds having . .
:

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conjugated olefinic unsaturation, such adducts being e~emplified by bicyclo[2.2.1]hept-5-en3-2,3-dicarboxylic anhydride, methyl maleic acid, and itaconic acid. Maleic acid or anhydride and fumaric acid are the most widely used commercially.
E~amples of saturated or aromatic dicarbo~ycyclic acids or anhydrides which may be used in the preparation of the polyesters are materials such as phthalic acid or anhydride, te~ephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid or anhydride, adipic acid, isophthalic acid, sebacic acid, succinic acid, and dimerized fatty acids.
Polyols useful in the preparation of the polyesters are materials s~ch as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, ~utylene glycols, neopentyl glycol, 1,3- and 1,4-butane diols, l,~-pentane diol, 1,6-he~anediol, glycerol, l,l,l-trimethyl~lpropane, bisphenol A, and hydrogenated bisphenol A~ It is also possible to employ the corresponding o~ides, sucb as e~hylene o~ide and propylene o~ide, etc. Generally no more than about 20% of the polyols employed in the preparation of a polyest~r are triols.
In addition to the above esters, one may also use dicyclopentadiene-modified unsaturated polyester resins described in V.S. Patents 3,9B6,922 and 3,883,612.
Another type of unsaturated polyester useful for preparation of polyester-based molding compositions is the group of materials known as - - ., - ~ , ........ . ~ , . : . . ,. ,, . :

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~inyl esters. These are reaction products of saturated polyesters possessing secondary hydroxyl functionalities with vinyl group-containing acids or anhydrides such as acrylic acid or methacrylic acid. An e~ample is the reaction product of an epo~y resin based on bis-phenol A with an unsaturated carbo~ylic acid such as methacrylic acid. Vinyl esters and their preparation are disclosed in US Patent 3,887,515.
The unsaturated polyester is generally employed in the composition at a level of between 20 and 5~%, preferably 36% to 4~%, by weight based on the weight of polyester, monomer, and low profile additive employed. In practice, it is usually employed as a 60-65% by weight solution in the olefinically-unsaturated monomer used for crosslinking.
The olefinically unsaturated monomer employed in the molding composition of the invention is a material which is copolymerizable with the unsaturated ester to cause ~rosslinking which effects the curing of the polyester. The monomer also serves the function of dissolving the polyester, thereby facilitating its interaction with the other components of the composition. Sufficient monomer is employed to provide convenient processing, but a large e~cess beyond that required is to be avoided since too much monomer may have an adverse effect on properties of the final composite material.
The monomer is generally employed in the ~omposition at a level of between 30 and 70%, . ' ,, , ~ ~, : . .

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preferably ~0 to 55%, by weight based on the weight of polyester, monomer, and any low profile additive employed.
By far the most commonly employed olefinically unsaturated monomer is styrene, although other monomers such as vinyl toluene isomers, methyl methacrylate, acrylonitrile, and substituted styrenes like chlorostyrene and alpha-methyl styrene may also be employed.
Another component of the compositions of the invention is a thermoplastic low profile additive, preferably a poly(vinyl acetate).
Suitable ~inyl acetate polymer low profile additives are poly(vinyl acetate) homopolymers and thermoplastic copolymers containing at least 50% by weight of vinyl acetate. Such copolymers include, ~- -for e~ample, carboxylated vinyl acetat~ polymers which are copolymers of vinyl acetate and ethylenically unsaturated carbo~ylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and the like or anhydrides such as maleic anhydride; vinyl acetate/vinyl chloride~
maleic acid terpolymer, and the like; ~tc.
Reference is made to US Patents 3,718,714 and 4,284,736, and British Patent 1,361,841 for descriptions of some suitable vinyl acetate polymer low profile additives.
The useful ~inyl acetate pol~mer low profile additivçs ordinarily have molecular weights within the ran~e from 10,000 to 250,000, prefera~ly from 25,000 to 175,000. They are usually employed in the composition at a level of 5 to 25 percent by . ~
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weight, preferably 10 to 20 percent by weight, based on the total weight of polyester resin, low profile additive, and monomer.
Other thermoplastic low profile additives besides poly(vinyl acetate)s should also serve in the compositions of the invention. E~amples of such materials are: poly(methyl methacrylate), polystyrene, polyurethanes, saturated polyesters, and ground polyethylene powder.
Yet another component of the compositions of the invention is a reinforcing filler such as glass fibers or fabrics, carbon fib~rs and fabrics, asbestos fi~ers ~r fabrics, various organic fibers and fabrics such as those made of polypropylene, acrylonitrile/vinyl chloride copolymer, and others known to the art. Such materials are ~enerally empl~yed at a level between 5 and 75 % by weight of the total composition, preferably lS to 50 % by weight.
Also included in the compositions of the invention is a blocked polyisocyanate, which is generally employed at a level of 1-20 parts per hundred, and preferably 1-10 parts per hundred, based on the total weight of the resin, the monomer, and the low profile additive.
A blocked isocyanate i5 an adduct of an isocyanate and an isocyanate-reactive material, this adduct bei~g stable at room temperature where processing takes place, ~ut diss wiating to .,, , . . . ~ . . . .

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'7 regenerate the isocyanate functionality at some temperature above room temperature, usually between 120C and 250~C.

R-N-C~0 > R~N=C~0 ~ R'-H
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more thermally stable units such as urethane (hydro~yl~isocyanate) or urea (amine+isocyanate) :
linkages.

R - N~CeO ~ Rn_XH > R-N-C=0 l l ' H ~R"

where X - N, 0, or S
:-E~amples of polyisocyanates which may beused as starting materials for the blocked isocyanates which are useful in the compositions of the invention are materials such as tetramethylene diisocyanate, he~amethylene diisocyanate (HMDI), ~:
1,4-cyclohe~ane diisocyanate, 1,3-cyclohegane diisocyanate, isophorone diisocyanate (IP~ ylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and straight or branched urethane polymers containing multiple isocyanate substituent groups, these polymers bDing synthesized from a simple ' , '. - " , :' . ': :' ' ;~.' : ~, , .. . : . ... , . ,. .: ,: : , . . ., , , :- , : , . , , ; , ~ . . . :

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polyisocyanate and at least one polyol having at least two active hydrogen atoms. Examples o~ the latter materials are isocyanate-containing prepolymers prepared by reaction of a toluene diisocyanate (TDI), or a methylenediphenylene diisocyanate (MDI) or polymeric form thereof (polymeric MDI), with a polyal~ylene o~ide diol such as polypropylene o~ide diol. Materials having three isocyanate groups may also be employed.

- Materials which may be used as blocking groups are compounds having a single active hydrogen atom. E~amples of blocking agents for isocyanates are:
phenols; for example, nonyl phenol, resorcinol, cresols, and bisphenol A.
imidazoles; for e~ample, imidazole, 1- or 2- methylimidazole, ~-phenylimidazole, 2,~,5-tri-phenylimidazole, 2,2'-bis(4,5-dimethylimidazole, and 4,5-diphenylimidazole.
pyrazoles; for e~ample, pyrazole, 3-methylpyrazole, 3,~-dimethylpyrazole, and 3,5-pyrazoledicarboxylic acid.
o~imes; for e~ample, 2-butanone oxime, dimethyl glyo~ime, cyclohexanone oxime, p-benzo~uinone dioxime, pinonic acid o~ime, benzophenone o~ime, and 4-biphenylcarbo~aldehyde o~ime.
materials having acidic hydro~en attached to carbon, such as acid esters, diketones, and beta-dicarbonyl compounds generally; for e~ample, dialkyl malonates, 2,4-pentanedione, and ethyl acetoacetate. -.. . : .: . . . :
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amides; for e~ample, caprolactam.
hydroxamic esters; for e~ample, ben~yl methacrylohydroxamate (~MH), and acetohydro~amic acid.
triazoles; for e~ample, ~enzotriazole, methylbenzotriazole, and 1,2,4-triazole.
alcohols; for e~ample, benzyl alcohol, ethanol, and butanol.
carbodiimides; for e~ample, carbodiimide reacts with isocyanate to form uretonimine.
furazon N-oxides; which react by opening the heterocyclic ring to form isocyanates.

Methods fOI synthesixing blocked isocyanates are well known to those skilled in the art. Typically, stoichiometrically equivalent amounts of the isocyanate compound and the blocking material are dissolved in separate portions o~ a suitable solvent, and one is added dropwise to the other with stirring and heating under an inert atmosphere. A catalyst may be employed, but is not always necessary. See, for example, Anagnostou and Jaul, Journal of Coatings Technology, 53, 35 (1981);
the re~iew articles by Z.W. Wicks in Progress in Organic Coatings, 9, 3 (1981), and ~, 73 (1975) also provide references to the original literature.
The dissociation temperature of a blocked isocyanate is generally a function of the structure of the blocking group, with alcohols > lactams >
phenols ~ oximes > active methylene compounds.
Aromatic blocked isocyanates usually disso~iate at lower temperatures than their aliphatic counterparts.

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Blocked isocyanate eompounds have been used in the coatings and related industries for many years. However, most blocked isocyanates have been marketed witb solvents present. These solvent-containing materials are not suitable for use in the molding process for fiber reinforced plastic since this process cannot tolerate the presence of non reactive solvents.
Blocked iso~yanates apparently have seldom been employed in polyester-based plastic compositions. Several references in which they have been used are discussed below.
U.S. Patent 4,542,177 of Xriek et al.
discloses a thermoplastic polyester molding composition comprising a blend of a thermoplastic polyester and a prepolymer derived from reaction of an organic polyisocyanate with an organic compound containing at least two isocyanate-reactive groups, this prepolymer containing blocked isocyanate ~roups. This molding composition is not based on an unsaturated polyester resin, does not employ an olefinically unsaturated monomer or a low profile additive, and does not contain an isocyanate-reactive material as used in the present invention.
Products produced using this molding composition are stated to have improved impact performance.
Japanese Kokai Patent No. 57-3Bl9 discloses a thermosetting polyester resin molding composition comprising an unsaturated polyester resin and blocked isocyanate. This molding composition does not include an isocyanate-reaotive material different from the unsaturated polyester resin, and . ~ . ' ~ ., . . . . ,: .:
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does not necessarily contain low profile additive or ~einforcing filler. Products made from the molding composition are stated to have e~cellent strength.
Japanese Kokai Patent No. 56-155216 discloses thermosetting polyester molding compositions comprising an unsaturated polyester and a low molecular weight olefinically unsaturated blocked isocyanate crosslinker. Molded products made from the composition are stated to have improved strength.
The isocyanate-reactive materials which are useful in the thermosetting molding composition of the invention are materials which contain active hydrogen atoms, such as polyether polyols, polyester polyols different from the unsaturated polyester resin (including those derived from polylactones), hydro~yl group-containing vinyl polymers, amine-terminated polyols, diamines, and polyamines.
In these materials primary hydro~yl groups and primary amino groups are preferred. The isocyanate-reactive materials are employed at levels between 1 and 20 parts per hundred, preferably 1 to 10 pph, based on the total weight of the resin, the monomer, and the low profile additive.
Polyols are the pre~erred isocyanate-reactive materials. Examples of suitable polyols are: hydroxyl-containing vinyl based polymers such as copolymers of Yinyl acetate or other vinyl esters with hydro~yl cont~ining unsaturated monomers, terpolymers of ~inyl chloride and vinyl acetate (or other vinyl esters) with hydro~yl containing ~nsaturated monomers, and also, hydrolyzed versions .
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of vinyl ester containing polymers; polyester polyols, diols, and triols, such as DEG/adipate, ethylene-butylene~adipate, condensation products of diols with dicarbo~ylic acids having more than 6 carbon atoms, and lactone polyolis such as - -polycaprolactones; polyether polyols, diols, and triols, such as polypropylene o~ide and ethylene o~ide capped PPO (which yields primary hydro~yls); :
and amine-terminated polyols such as amino terminated polypropylene o~ide or polypropylene o~ide/polyethylene oxide polyethers.
The molding co~positions of the invention may also contain one or more conventional additives, which are employed for their known purposes in the usual amounts. The following are illustrative of such additives: -1. Polymerization initiators such as t-~utyl hydropero~ide, t-butyl perbenzoate, benzoyl pero~ide, t-butyl peroctoate, cumene hydropero~ide, methyl ethyl ketone pero~ide, and others known to the art, to catalyze the reaction between the olefinically unsaturated monomer and the olefinically unsaturated polyester. The polymerization initiator is employed in a catalytically e~fective amount, such as from about ~.
0.3 to about 2 to 3 ueight percent, based on the total weight of the polyester, monomer, and low profile additive;
2. Fillers such as clay, alumina trihydrate, silica, calcium carbonate, and others known to the art;

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3 ~, 3. Mold release agents or lu~ricants, such as zinc stearate, calcium stearate, and others known to the art; and 4. Rubbers or elastomers such as: a) homopolymers or copolymers of conjugated dienes containing from 4 to 12 carbon atoms per molecule (such as 1,3-butadiene, isoprene, and the like), the polymers having a weight average molecular weight of 30,000 to 400,000 or higher, as described in ~S
Patent 4,020,036; b) epihalohydrin homopolymers, copolymers of two or more epihalohydrin monomers, or a copolymer of an epihalohydrin monomer(s) with an o~ide monomer(s) having a number average molecular weight (Mn) which varies from 8D0 to 50,000 as described in US Patent 4,101,604; c) chloroprene polymers including homopolymers of chloroprene and copolymers of chloroprene with sulfur and/or with at least one copolymerizable organic monomer wherein chloroprene constitutes at least 50 weight percent of the organic monomer make-up of the copolymer, as described in US Patent 4,161,471; d) hydrocarbon polymers including ethylene/propylene dipolymers and copolymers of ethylene/propylene and at least one nonconjugated diene, such as ethylene/propylene/
he~adiene terpolymers and ethylene/propylene/ : .
1,4-he~adiene/norbornadiene, as described in US
Patent 4,lÇl,971; e) conjugated diene butyl elastomers, such as copolymers consisting of from 85 to 99.5 percent by weight of a C4-C7 olefin combinPd with 15 to 0.5 percent by weight of a conjugated multi-olefin having 4 to 14 carbon atoms, and copolymers of isobutylene and isoprene where a major : . : , . ,,: , - . . .. ..

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portion of the isoprene units combined therein have conjugated diene unsaturation, as described in US
Patent 4,160,759.
Thickening agents are also fre~uently ~mployed in the compositions of the invention.
These materials are known in the art, and i~clude the o~ides and hydro~ides of the metals of Groups I, II, and III of the Periodic Table. Specific illustrati~e e~amples of thickening agents include magnesium oxide, calcium o~ide, zinc oxide, barium oxide, calcium hydroxide, magnesium hydro~ide, and mixtures thereof. Thickening agents are normally employed in proportions of from about 0.1 to about 6 percent by weight, based on the total weight of the polyester resin, monomer, and low profile additive.

ÇlQssarY of Terms and Definitions of Mate~ials Alumina Trihydrate a commercially-available filler.
9MC bulk molding compound.
Camel white Calcium carbonate filler available from GenStar Stone Products.
CaSt calcium stearate. -Desmocap 11~ a branched aromatic urethane polymer with ether groups, containing 2.4% blocke~ MCO
content. This i5 a solid material available from Mobay Corporation.

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Desmocap 12a a linear aromatic urethane polymer with ether groups, containing 1.7% blocked NCO
content. This is a solid material available ~rom Mobay Corporation.
Gamma Plas Calcium carbonate filler available from Georgia Marble.
JM 615G 1" fiberglass from Manville Corp.
LP-40A Acid-modified poly(vinyl acetate), 40% in styrene.
LPS-40AC Solid acid-modified poly(vinyl acetate).
MDI methylene diphenylene diisocyanate.
Microthene Cryogenically ground polyethylene powder available from USI, Quantum Corp.
Millicarb Calcium carbonate filler from Omya.
Mod E 5% parabenzoquinone solution in diallyl phthalate.
MR-13017 Isophthalic acid modified polyester resin available from Aristech Chemical, containing about 35 weight percent styrene.

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MR-13031 Orthophthalic acid modified polyester resin availa~le from Aristech Chemical, containing about 35 weight percent styrene.
Palapreg P-18 Maleic anhydride/propylene glycol polyester resin containing about 35 weight percent styrene and available from BASF.
pBQ parabenzoguinone.
PDO 50% t-butyl peroctoate availablQ from Lucidol Corp.
PG-9~33 MgQ (35% dispersion) available from Plasticolors, Inc.
PPC-3029 fiberglass reinforcement (1/2") from PPG Industries.
SMC sheet molding compound.
t9PB t-butyl perbenzoate.
TONE ~301 polycaprolactone triol available from Union Carbide Chemicals and Plastics Co, InC.
Trigono~ 29B7~ a peroxy ketal available from Akzo Corp.
UCAR~ VYES-4 a terpolymer that contains appro~imately 29% primary hydro~yls, available from Union Carbide Chemicals and Plastics Co., Inc.

3~ J
- 2~ -ZMC untnickened injection molding compound similar to unthickened BMC, with a glass content of 20% by weight.
ZnSt zinc stearate.
XLP-4022 a 37 weight percent acid modified poly(vinyl acetate) solution in styrene, available from Union Carbide Chemicals and Plastics Co., ~ .
Inc.

, Experimental Procedure for Nonyl Phenol Blockina ~ an ~DI Terminated Polyo~YalkYlene Glycol.
Nonyl phenol (I) was obtained as a 99%
mi~ture of monoalkyl phenols. The MDI terminated polyo2yalkylene glycol (II) was o~tained as a 75%
solution in styrene~ The isocyanate content of (II) was determined by the method given by Siggia in ~Qua~titative Organic Analysis via Functional Groups," John Wiley and Sons, 1962, p~59. One mole of (I) was taken to react with each mole of isocyanate present in (II). The quantity of (I) needed to cap all of the isocyanate groups present in (II), where (II) was MDI terminated polyoxypropylene glycol, was calculated as shown below.
g(I~ z g(II) x~g i60cy~nate x 1 ~mole x 220 g~g~l~mol~
100 g(lI~ 42 g 16~cyanate - . . : . ~ -, , , .. , . ~ ~ , . . . . ..
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~ecause nonyl phenol is an inhibitor of pero~ide initiators found in the molding compound (BMC), g(I) was multiplied by a factor of 0.98 to insure ~o free nonyl phenol at end o~ reaction.
A weighed amount of (II) was placed ~n a three neck reactor of appropriate size, then 100 ppm of parabenzoquinone and 100 ppm of triethylene diamine were added. The reaction mi~ture was blanketed by a 4~ oxygen/96% nitrogen mixture, then heated to 60C under constant agitation, and this temperature was maintained throughout the reaction.
The phenol SI) was then diluted with styrene to give a SOD~ solution and added dropwise to the reactor.
Beginning at four hours, specimens ~ere taken for deter~ination of free isocyanate content as referenced above. When the free isocyanate content had dropped to ~0.1~ butanol was added in slight e~cess to react with any remaining isocyanate. At 0.0% isocyanate the reactor was cooled and dumped.
The product was used as made.
Blocked isocyanates synthesized in this work are discussed below. Each was composed of MDI, nonyl phenol (as the blocker), and varied by the molecular weight of propylene glycol polyol. No free isocyanate was present due to blocking with nonyl phenol.

~:xamPle 1 P~eDaratio~ of ~locked Isoc~anate A

Following the procedure gi~en abo~e, a blocked isocyanate was prepared from a 75% solution , :, ,: .- .. .- , , .. .... - . . ,, . . .: " , ,. .. - : . ., ... ., .: .
. ~ ... . , . . . . :. .... , . . ., .. . , ............ .. . : . : . .
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in styrene of an is~cyanate prepolymer based on MDI
and a 2000 molecular weight polypropylene o~ide diol. The free NCO content of this prepolymer solution was 2.4 % before blocking.

~am~le 2 PreParation of Blocked Isocyanate B

Following the procedure above a blocked isocyanate was prepared from a 50% solution in styrene of an isocyanate prepolymer based on MDI and a 2000 molecular weight polypropylene o~ide diol.
The free NCO content of this prepolymer solution was 0.5% before blocking.
.
Preparation o~ the Moldina Com ositions The comp~sitions of the invention are prepared by mi~ing the components in a suitable apparatus such as a Hobart mi~er, at temperatures on the order of about 2~C to about 50C. The components may be combined in any convenient order.
Generally, it is preferable that the thermosetting resin and the low profile additive are added in liquid form by preparing a solution of ~hese materials in styrene ~r some other liquid copolymerizerable monomer. All the liquid components, including the blocked isocyanate and the isocyanate-reactive material (preferably a primary polyol), are usually miged together before adding fillçrs and the thickening agent. Tbe fibergla~s is added after the thickening agent. Once formulated, ,, ~ , , . . , ~ , , ,::, : , - , : :,; -: ,, :. ....
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3~11,, 2;~, the compositions can be molded into thermoset articles of desired shape, particularly thermoset articles such as automobile body parts. The actual moldin~ cycle will depend upon the particular composition being molded as well as upon the nature of the cured product desired. Suitable molding cycles are conducted on the order of about 100C to about 182C for periods of time ranging from about 0.5 minutes to about 5 minutes. This depends on the particular pero~ide catalyst employed.

General ReciDe fcr Bulk Moldinq ComDound (BMC~ Compositions Material P~W* -Unsaturated polyester (60-65 weight % in styrene) 60 . .
Low profile additive (33-40% in styrene) 40 Recipe for BMC, continued Blocked isocyanate 1 10 Reactive coupling material (e.g., polyol) 2-5 Pero~ide catalyst (t-bu perbenzoate) 1.5 5% pBQ

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Mold release (zinc stearate) 4 Filler ~calcium carbonate) 230 Fiberglass (as a percentage of the total composition) 1~.0 weight percent Amounts given in parts per hundred, based on the total weight of the resin, the monomer, and the low profile additive, except as otherwise noted.

General Procedure for PreParation of Bul~ Moldin~ -Compound (~MC) Formul-at-iQns A11 the liquid components were weighed individually into a Hobart mi~ing pan placed on a ~alance. The pan was attached to a Model C-100 Hobart miser located in a hood. The agitator was started at slow speed, then increased to ma~imum speed to completely mix the liquids over a period of 3-5 minutes. The agitator was then stopped and the internal mold release agent was ne~t added to the liquid. The mi~er was restarted and the mold release was mi~ed with the liguid until it was completely wet out. The filler was negt added to the pan contents with the agitator off, then mixed using a medium to high speed until a consi,stent paste was obtained. The mi~er was again stopped, a weighed amount of thickening agent was added, and ' .

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then this was mi~ed into the paste using a slow to medium speed over a period of ~-3 minutes. The mi~er was stopped again and about 175 grams of the paste were removed from the pan using a large spatula, and transferred to a wide-mouth ~ oz bottle. The bottle was capped, and the paste sample was stored in the capped bottle at room temperature and viscosity was measured periodically using a model HBT 5X Brookfield Synchro-Lectric Viscometer on a Helipath.
After removal of the paste sample, the composition was reweighed and styrene loss was made ~p, and chopped glass fibers were added slowly to the pan with the mi~er running on slow speed. The mixer was then run for about 30 seconds after all the glass was in the paste. This short mixing time gave glass wet-out without degradation of the glass. The pan was then removed from the mi~er and separate portions of the BMC mix of about 1200 grams each were removed using a spatula and were transferred to aluminum foil sheets lying on a balance pan. Each portion of the mix was tightly wrapped in the aluminum foil (to prevent loss of styrene via evaporation) and stored at room temperature until the viscosity of the retained paste sample reached an appropriate molding viscosity. The weight of the BMC added to the foil varies with the molding application.

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General ~ecipe ~or Shee~ Moldina Com~ound (SMG~ Com~o~itions Material Unsaturated Polyester (60% in Styrene) 60 Low profile Additive (33-40~ in Styrene) 40 Filler ~Calcium Carbonate) (3-5 micron particle size) 150 70-75%
Pero~ide Catalyst ~t-Bu perbenzoate) 1.5 Mold release ~zinc stearate) 4 Thickener (MgO) .~-1 J
(as needed) Chopped glass fiber (one inch) } 30-25%
x Amounts giYen in parts per hundred, based on the total weight of the resin, the monomer, and the low profile additive. Numbers in the right-hand column refer to the respective percentages of the composition and glass.
~e~eral Procedure for Preparation of Sheet Moldina ComPound (SMC) Formulations -~' :
All the liquid components were weighed individually into a five gallon open top container on a Toledo balance. The contents of the container were then mixed in a hood with a high speed Cowle~
type dissolver. ~he agitator was started ~t a slow speed, then increased to ma~imum speed to completely ,: ' . . ' , ' ', ' ' ': ' ' ' . ' ~ :- . . , .: . : . :
:, - ~ - . ' , .~ ~.:, 7~,l;,3~, mi~ the liquids over a period of 2-3 minutes. The mold release agent, if one is desired, was ne~t added to the liquids and mi~ed until completely dispersed. The filler was next added gradually from a tared container until a consistent paste was obtained, and the contents were further mi~ed to a minimum temperature of 90~F. The thickener, if used, was ne~t mi~ed into the paste over a period of 2-3 minutes, the mi~er was stopped and about 175 grams of paste were removed from the container and transferred to a wide mouth 4 oz bottle. This paste sample was stored in the capped bottle at room temperature and its viscosity was measured periodically using a model ~BT 5X Brookfield Synchro-Letric Viscometer on a Helopath Stand. The remainder of the paste was ne~t added to the doctor ~o~es on the SMC machine where it was further combined with fiber glass ~about 1 inch fibers).
The sheet molding compound (SMC) was then allowed to mature to molding viscosity and was then molded into :
the desired articles.

Apparatus and Process for Preparation of Moldinq Test Panels Flat panels for surface evaluation were molded on a 200 ton Lawton press containing a matched dye set of lBn~18" chrome plated molds. The female cavity is installed in the bottom and the male portion is at the top. Both molds are l~
electrically heated and are controlled on separate circuits 50 that they can be operated at different ' '- ' : ~ .. ' ' . :,'. ~ .. ' ,...... .

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, temperatures. For the present molding, the top and bottom temperatures were 295-305 F, 12009 samples of molding compound were employed, and the molded part thickness was 0.12~". The molding pressure, which can be varied from 0 to 1000 psi, was run at magimum pressure. The panels were laid on a flat surface, weighted to keep them flat, and allowed to cool overnight. The molded panels were measured with a micro caliper from corner to corner in all four directions to determine shrinkage, which is an average of the four readings. These panels were used for surface smoothness determinations.

Sh~inkaae Meas~remen~

18"x18"xl/8" flat panels were molded in a highly polished chrome plated matched metal die mold in a 200 ton Lawton press, as described above. The e~act dimensions of the four sides of this mold were measured to ten-thousandths of an inch accuracy, at room temperature. The exact lengths of the four sides of the flat molded panels were determined to the same degree of accuracy. These measurements were substituted into the equation below:

(a-b)/a ~ inch~inch shrinkage where a , the sum of the lengths of the four sides of the mold, and b = the sum of the lengths of the four sides of the molded panels.

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The shrink control test compares the perimeter of a cold panel to the perimeter of the cold mold. A positive number indicates an e~pansion and vice-versa for a negative number as compared to the cold mold. The units mil/inch indicate the amount of e~pansion (~) or contraction (-) in mils per inch of laminate (or panel perimeter).

Evaluation of Surface Smoothn~ss - The faithful reproduction of a reflection of a light grid's 1" ~ 1~' squares on the surface of a molded panel gave a visual picture of the surface smoothness. A quantitati~e evaluation of surface quality was obtained by comparing two panels simultaneously and picking the panel with the best reproduction of the reflected squares. This technique was repeated until the surface of every panel in the series was compared to all other panels. Surface smoothness was measured as a frequency, or number of times that a panel was picked as being the best in surface quality.
Therefore, the highest number denotes the best panel; the lowest number, the worst panel.

BMC RESULTS

Bulk molding compositions were prepared with and without Desmocap llA to test the effects of the presence of a blocked polyisocyanate in such compositions. The ingredients and their amounts are listed in Table I below.

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Table I
Effect of Blocked Is~cYanate in B~lk Moldina Com~sitions Component E~mPle Numbe~s #3 #4 Palapreg P-18 53 ~3 Desmocap 11~ x Styrene 5 5 tBPB 1.5 1.5 PDO 0.25 0.25 Mod E 0.~ 0.4 Ca St 2 2 Zn St 2 2 Camel white 230 230 PPG-3029 fiberglass, 20% by wt. in each composition Fle~ural Properties: #3 #4 Fle~ Modulus (mpsi) 2.02 1.99 Fle~ Strength (psi) 12760 15200 Est. Energy at Break (in-lbs) 3.2 4.5 ~ .
* Amounts given in parts per hundred, based on the -~
total weight of the resin, the monomer, and the low profile additive, escept as otherwise noted.
The results shown in Table I demonstrate that a block~d polyisocyanate can lead to an increase in fle~ural properties of the resulting composite relative to the composite lacking this additive. The ; .
~ontrol formula, E~ample #3, gives a laminate about 20% lower in fleg strength and about 40% lower in break energy than the material containing blocked isocyanate, Example #4. The greater increase in .
break versus fle~ strength reveals that E~ample #4 not only achieves higher loads but also a greater .. , : ,: . . . , . . :~
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;~q`~ ;3 amount of deflection before failure. Furthermore this improvement was obtained at the relatively low level of 1 phr of additive.
Additional e~perimental bulk molding compositions were prepared, in which the amounts of the blocked polyisocyanate and styrene monomer were varied, and in one of these trials (E~ample #8) the additional reactive polyol UCAR VYES-4 was included.
The compositional makeup and test results relating to th~se composites are shown in Table II below.

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BlDcked I60cyanate Effect6 Component Example N~mbers 1~5 #6 #7 #8 #9 LP-40A 42.3 42.3 42.3 42.3 42.3 Desmocap llA x 1.4 2.8 1.~ x Styrene 4.7 3.3 1.9 0.9 4.7 Table II, continued ~CAR VYES-4 x x x 2.4a x tBPB 1.5 1.5 1.5 1.5 1.5 PD~ ~.25 0.25 0.25 0.25 0.25 C~ S~ 2 2 2 2 2 Zn St 2 2 2 2 2 Millicarb 230 230 230 230 230 ~PG-3029 fibergla~s 20% by wt.
.
Flexural Properties: #5 ~6 ~7 ~ ~9 Flex ~odulus ~mpsi) 2.38 2.51 2.35 2.532.32 Flex Strength (psi) 12960 16280 163701860011510 Est. En~rgy at Break (in-lbs~ 2.8 3.7 4.3 4.2 2.1 Surface Properties: ~5 #6 ~7 ~8 #9 Surface Smoothne~s (freq) 11 9 12 17 7 Shr~nk Control (mil/in) -0.041 0.1660.2220.166 0.027 * Amount~ en in parts per hundred, based on the toSal weight of the re~in, the monomer, and the low profile additive1 eacept as otherwi6e ~oted.
a) Thi~ material W~8 predissol~ed in the LP-40A before add;tion to the formulation.
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The results shown in Table II are further evidence that a blocked polyisocyanate provides increased fle~ural strength and break energy. The control materials #~ and ~9 containing no blocked polyisocyanate were appro~imately 33% lower in strength and about 60% lower in break energy than test composites #6 and #7, which contained blocked polyisocyanate. Again, these results were achieved at relatively low levels of blocked polyisocyanate.
E~ample #8, which contained reactive polyol UCAR
VYES-4 in addition to blocked polyisocyanate, exhibited an increase in flex strength over the composites of trials #6 and #7. -Table II also includes an evaluation of the surface properties, surface smoothness, and shrink control of the test composites. The blocked polyisocyanate provided a minor but positive contribution to shrink control. More noticeably, the addition of reactive polyol UCAR~ VYES-4 in E~ample #8 substantially improves the surface quality of the composite.

Several test compositions based on a ZMC
formulation were prepared, each containing one of two blocked polyisocyanates, and three containing an additional reactive polyol. The styrene level was also varied. These compositions and amounts of ingredients are listed in Table III below.

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TABLE III
Bloeked Isocyanates with Various Polyols Component . Exam~le N~mbers _ _ #10 #11 ~12 ~13 #14 ~R-13û31 53 53 53 53 53 Table III, cont;nued LP-4ûA 42.3 42.3 42.3 42.3 42.3 - Desmocap llA 2.35 x 2.35 2.35 x Desmocap 12A x Z.35 x x x UCAR VYES_4a x x Z.35 x x .
TONE 03ûl x x x 2.35 x Styrene 2.35 2.35 x x 4.7 tBPB 1.5 1.5 1.5 1.5 1.5 PDO û.25 û.25 û.25 0.25 0.25 Mod E û.4 0.4 0.4 û.4 0.4 Ca St 2 2 2 2 2 Zn St 2 2 2 2 2 Millicarb 23û 230 23û 230 23û
PPG-3029 ~;berglas 20'~ by we;ght in all samples Flexural Properties: #10 ~Ll #12_~L~ #14 Flex Modulus (mpsi) 1.85 1.83 1.921.54 1.~
Flex Strength (ps~) 10850 17340 1715014420 1126Q .
~st. Energy at Break (in-lbs) 2.9 6.5 6.5 5.4 3.4 : .
Flex Prop., postbakùd: _l~lQ 3~Ll #12#13 ~14 Flex M~dulus (mpsi) 1.78 2.1 1.891.72 1.89 : .:
Flsx Strength ~psi) 11150 17000 1693û14420 1138û
st. Energy at Break (in-lbs) 3.1 6.2 6.1 5.7 3.2 . . .'' ' ' -', : ' "' - "' " ' " .' ' " ''' " ' , . ' ~ ~, ' ." '. :' ..
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~,~3~ 3~, Table III, c~ntinued 5urface Pr~perties: #10 #11 #12 ~13 ~14 Surface Smoothness 10 15 22 27 9 (freq.) Shrink Control (mil/in) û.263 0.361 0.333 0.374 û.182 ~ Amounts given in parts per hundred, based on the total weight of the resin, the monomer, and the low profile additive, except as otherwise noted.
a) This Dateria~ w~s prediss~lved in the LP-4ûA before introducti~n ;nto the fon~ulati~n.

In Table III the blocked polyisocyanates Desmocap llA and 12A were evaluated in a polyester resin based ZMC formulation with respect to surface guality, shrink control, and flex properties.
~esmocap llA was also compounded with polyisocyanate reactive polyols such as UCAR~ VYES-4 and TONE ~301.
The control formulation contained LP-40A.
In the surface quality evaluation virtually all sf the compositions containing blocked polyisocyanate outperformed the control composition lacking these additives. Further~ the panels that contained ~he reactive polyols UCAR~ VYES-4 and TONE
D301 had shrink control values >~0.300 and had egcellent surface guality with good gloss. These were the best panels of the surface quality ~ -evaluation.
: In the fle~ property evaluation study, the control laminate #14, containing only LP-40A, ... . . . . . . . .. . .

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~g~ ;}~3 attained slightly higher than typical ~MC fle~
strength of approximately 11,000 psi and an energy to break of about 3.4 in-lb. Composition #12, containing both Desmocap llA and the polyol coupling agent VCAR~ V~ES-g, had the highest fle~ strength and break energy of all the compositions containing Desmocap 11~, namely, 17,150 psi and 6.5 in-lb, respectively. ~owever, in composition #10, Desmocap llA alone failed to confirm previous results of a significant increase in flex properties, showing a fle~ strength of 10,850 p5i and an energy at break of 2.9 in-lb. It appears that to obtain a consistent increase in flex performance from a blocked polyisocyanate the addition of a reactive polyol such as the ~CAR~ VYES-4 is required.
To ascertain if there was any residual unreacted polyisocyanate in these laminates they were postbaked at 300F for 20 minutes. Comparing the fle~ results of baked versus unbaked laminates, it can be seen that there is ~ery little difference between the two. Therefore, it would appear that most of the blocked polyisocyanate is reacted during the molding step.
Further trial compositions to evaluate the effects of other blocked polyisocyanates in the presence of the primary polyol UCAR~ YVES-4 were prepared in the same manner as those discussed abo~e. The inyredients and their amounts are listed in Table IV below.

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TABLE ~V
Blocked Isocyanates ~ith a Primary Polyol Component Example N~mbers #1~ #16 ~17 #18 #19 #20 ~21 ~22 #23 MR-13031 J3 83 53 53 53 ~3 ~3 53 53 LPS-40ACa 16.8 16.816.8 16.8 16.8 16.8 16.816.8 16.8 UCAR W ES-4a 2.3 2.3 2.3 2.3 2.3 2.3 x 2.33 2.3 Styrenea 23.2 23.223.2 25.6 25.6 25.6 30.227.9 27.9 Blocked isocyanate A 4.7 x x 2.3 x x x x x Ulocked isocyanate ~ x 4.7 x x 2.3 x x x Desmocap 12A x x 4.7 x x 2.3 x x x tbPB 1.~ 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 PD0 0.25 0.250.25 D.25 0.25 0.25 0.250.25 0.25 Ca St 2 2 2 2 2 2 2 2 2 Zn St 2 2 2 2 2 2 2 2 2 ~illicarb 230 230 Z3D 230 230 230 230 230 230 PPG-3029 fiberglass 20% by weight ;n each sample.
Flexural Propert;es: #15 #16 #17 #1~ #19 ~2Q #21 #22 ~_ Flex HDdulus (mps;) 2.8 2.1 1.78 2.05 1.97 1.96 2.1 2.1 1.85 Flex Strength (ps;) 174201790013185185702014516~30 14580 12180 11180 Est. ~nergy at Break (in-lbs.) 6.9 7.2 5.1 B.l 9.4 6.7 4.5 3.3 3.2 Impact Propert;esi #15 ~ #17 #18 #19 #20 ~21 #22 #23 Unnotched I~od (in-lb/;n) 10.2 10.5 9.1 lZ 12.2 13.1 8.6 7 9 Notched Izod (in-lb/in) 8.9 10.3 7.3 8.7 7.4 B.8 8.6 7.22 lû.2 Surface Properties #15 #16 #17 i la #19 ~Q #21 #22 #23 Surface SmDothness tfreq.) 6 10 12 16 18 12 12 x x Shrink Control ~m;l/in) 0.337 0.324 0.445 0.311 0.351 0.405 0.202 0.324 0.216 Amounts given ;n parts per hundred, based on the total weight of the res;n, the ~onomer, and the low profile add;t;ve, except as otherwise noted.
a) The LPS-40AC, UCAR VES-4, and styrene were predissolved together before introduction to the formulation.

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These e~periments indicate that the synthesized blocked isocyanates perform well when combined with the reactive polyol. The reacti~e polyol without blocked isocyanate yields poor results.
A sheet molding formulation was made up with and without the blocked polyisocyanate Desmocap 12A
and polyol UCAR~ VYES-4 in the manner descri~ed above, to test the effects of these additives in sheet molding compositions. The ingredients and amounts are given in Table V below.

TABLE V
Corroborating Evidence in SMC
E~ample Numbers #24 ~25 MR-13017 ~3.9 63.9 LP-40A 32~5 36.1 UCAR VYES-4a l.B ~ -Desmocap 12A l.B x Styrene 5 5 Trigono~ ~9B75 1.1 1.1 Mod E 0.3 0.3 Microthene 4 4 - ::
Zn St 5.6 5.6 Pigment 19.1 14.1 Alumina Trihydrate 33.3 33.3 5amma Plas 133.3 133.3 JM 615G, 1" fiberglass 14% by wt. 14% by wt.
PG-9033 1.5 1.5 Fle~ural Properties: #24. ~
Fle~ Modulus (mpsi) 1.53 1.35 Fle~ Modulus (psi) 17950 11300 - .
Est. Energy at Break (in-lbs) . 10.2 5.7 Impact Properties: #Z4 ~25 Notched Izod 10.6 7.6 Vnnotched Izod 10.8 9 * AmouDts given in parts per hundred, based on the .
. . . . ..
' . ': ' ,' .. ' ', . ' '' . ' . '',, :

. . . .
. . -. : . . - : : . . : . .

, ~. , . , . ,:
,- : ,, . ' ,. ' : .' : .,~ ., :.
, . . . .

- ~3 -total weight of the resin, the monomer, and the low profile additive, e~cept as otherwise noted.
a) This material was predissolved in the LP-40A
before intro~uction into the formulation.
Table v shows the increase in physical properties in sheet molding compound as a result of adding a blocked polyisocyanate and additional polyol to the formulation. Increases of appro~imately 55%
and 75% are seen in flex strength and break energy, respectively, over the LP-40A control. Izod impact results, though not as dramatic, are also higher than the control.
Other embodiments o~ the invention will be apparent to the skilled in the art from a consideration of this specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as egemplary only, with the true scope and spirit of the invention being indicated by the following claims.

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: .. . .
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Claims (9)

We claim:

1. A thermosetting molding composition, comprising:
a) an unsaturated polyester resin;
b) an olefinically unsaturated monomer;
c) a thermoplastic low profile additive;
d) a reinforcing filler; and further including:
e) a blocked polyisocyanate; and f) an isocyanate-reactive material different from said unsaturated polyester resin.

2. The molding composition of claim 1, wherein said blocked polyisocyanate is the blocked form of a polyisocyanate selected from the group consisting of tetramethylene diisocyanate, hexamethylene diisocyanate (HMDI), 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate (IPDI), xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and isocyanate-containing prepolymers prepared by reaction of a toluene diisocyanate (TDI) or a methylenediphenylene diisocyanate (MDI) or polymeric form thereof (polymeric MDI) with a polyalkylene oxide diol.

3. The molding composition of claim 1, wherein said isocyanate-reactive material is selected from the group consisting of polyether polyols, polyester polyols different from said unsaturated polyester resin, hydroxyl group-containing vinyl polymers, amine-terminated polyols, diamines, and polyamines.

4. A thermosetting molding composition, comprising the following materials, the amount of each being given in parts per hundred based on the total amount of polyester resin, monomer, and low profile additive except for the reinforcing filler:
a) from 20 to 50 pph of an unsaturated polyester resin;
b) from 30 to 70 pph of an olefinically unsaturated monomer;
c) from 5 to 25 pph of a poly(vinyl acetate) thermoplastic low profile additive;
d) from 5 to 75 % by weight, based on the total composition, of a reinforcing filler;
e) from 1 to 20 pph of a blocked polyisocyanate which is the blocked form of a polyisocyanate selected from the group consisting of isocyanate-containing prepolymers prepared by reaction of a toluene diisocyanate (TDI), or a methylenediphenylene diisocyanate (MDI) or polymeric form thereof (polymeric MDI), with a polyalkylene oxide diol; and f) from 1 to 20 pph of a polyol selected from the group consisting of polyether polyols, polyester polyols different from said unsaturated polyester resin, and hydroxyl group-containing vinyl polymers, each of these materials containing primary hydroxyl groups.

5. A process for preparing a reinforced thermoset molded composite, comprising the following steps:
A. preparing a thermosetting molding composition comprising:
a) an unsaturated polyester resin;
b) an olefinically unsaturated monomer;
c) a thermoplastic low profile additive;
d) a reinforcing filler, and further including:
e) a blocked polyisocyanate; and f) an isocyanate-reactive material different from said unsaturated polyester resin;
B. forming said molding composition into a desired shape; and C. heating the shaped molding composition to cure it.

6. The process of claim 5, wherein said blocked polyisocyanate is the blocked form of a polyisocyanate selected from the group consisting of tetramethylene diisocyanate, hexamethylene diisocyanate (HMDI), 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate (IPDI), xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and isocyanate-containing prepolymers prepared by reaction of a toluene diisocyanate (TDI) or a methylenediphenylene diisocyanate (MDI) or polymeric form thereof (polymeric MDI) with a polyalkylene oxide diol.

7. The process of claim 5, wherein said isocyanate-reactive material is selected from the group consisting of polyether polyols, polyester polyols different from said unsaturated polyester resin, hydroxyl group-containing vinyl polymers, amine-terminated polyols, diamines, and polyamines.

8. A molded reinforced thermoset product made with the composition of claim 1.

9. A molded reinforced thermoset product made by the process of claim 5.