JPS62267349A - Low-shrinking thermosetting resin composition - Google Patents

Abstract

PURPOSE:To provide a composition of good storage stability, low in shrinkge when cured, capable of giving cured product of outstanding surface smoothness and glass, causing no mold stain and color uneveness, comprising a specific hydroxyl group-contg. (meth)acrylate polymer and thermosetting resin. CONSTITUTION:The objective composition comprising (I) a hydroxyl group-contg. (meth)acrylate polymer of formula I [R is H or methyl ; Z is 2-8C divalent organic group ; (A) is ring-opened group of alkenyl glycidyl ether of formula II; R<1> is H or <=20C (halogen-substituted) hydrocarbon; R<2> is <=20C alkenyl; (B) is ring-opened group of cyclic compound of formula except the formula II; K is 1-20; l is 0 or 1-20; the arrangement of the ring-opened groups of said cyclic compounds respectively expressed by the A and B is arbitrary; X is residue of monomer having radically polymerizable double bond; m is positive integer; n is 0 or positive integer] and graft-modified product therefrom and (II) a thermosetting resin.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermosetting resin composition that exhibits small volume shrinkage upon curing. .

(Prior Art) Thermosetting resins such as unsaturated polyester resins undergo significant shrinkage during molding and curing, causing problems such as cracks and surface waviness, resulting in poor surface smoothness. All of these problems are caused by volumetric shrinkage during resin curing. Conventionally, as a method to solve such problems, polystyrene, polymethyl methacrylate, polyvinyl acetate, saturated polyester, ethylene-
After dissolving a thermoplastic resin such as vinyl acetate copolymer or polyurethane into a G body that can be copolymerized with a thermosetting resin, it is dissolved or dispersed in the thermosetting resin, and heat is applied when the thermosetting resin is cured. A method of reducing the shrinkage rate by precipitating a plastic resin has been proposed, and some improvements have been made.

(Problems to be Solved by the Invention) However, these conventional methods have problems with the storage stability of the resulting resin composition, causing uneven coloring and mold staining, and
Moreover, the low shrinkage effect may also be insufficient in some cases.

These disadvantages include poor dispersibility of the thermoplastic resin in the resin composition, the thermoplastic resin may separate and float on the surface, or the dissolved thermoplastic resin may not precipitate uniformly. This occurs due to the following causes.

As mentioned above, although the conventional method for reducing shrinkage achieves a certain degree of reduction in shrinkage, there remain problems in mold staining and color unevenness that accompany the reduction in shrinkage.

The present invention was made in view of the above points, and its purpose is to provide a cured molded product that has poor storage stability, low shrinkage during curing, good surface smoothness and gloss, and is free from mold stains. An object of the present invention is to provide a low-shrinkage thermosetting resin composition that does not cause color unevenness.

(Means and effects for solving the problems) The present inventors have explained the current situation and, as a result of α-examination, have developed a hydroxyl group-containing compound having a novel structure and containing methacrylate as a constituent component. meth)acrylate polymer (a) and/or its graph 1 to modified product (
The present invention was completed based on the discovery that a composition comprising a') and a thermosetting resin (b) provides a molded product with low shrinkage, good surface smoothness, and no uneven color.

The present invention is based on the general formula [wherein R is a hydrogen atom or a methyl group, and Z
represents a divalent organic group having 2 to 8 carbon atoms, <Δ) is a 17il 1M group of alkenyl glycidyl ethers represented by the following general formula (II>), and (B) represents a 17il 1M group of alkenyl glycidyl ethers represented by the following general formula (II>).
[) represents a ring-opening group of a cyclic compound excluding alkenylglycidyl needles, k is an integer of 1 to 20, f
+cto or an integer from 1 to 20, and (A>
, the arrangement of the ring-opening group of the alkenyl glycidyl ether or cyclic compound represented by (B) is arbitrary,
m represents a positive integer, and n represents O or a positive integer.

A low-shrinkage thermosetting resin composition comprising a hydroxyl group-containing (meth)acrylate polymer (a) and/or its graft modified product (a') represented by: and a thermosetting resin (b) It is about things.

(Note) [In the formula, R1 is a hydrogen atom or a hydrocarbon group having 20 or less carbon atoms (1% ' halo), and R2 is a hydrogen atom having 20 or less carbon atoms
It is an alkenyl group of 0 or less. ] Hydroxyl group-containing (meth) constituting the low-shrinkage thermosetting resin composition of the present invention
The acrylate polymer (a) has the general formula % formula % () [wherein, R is a hydrogen atom or a methyl group, and Z
is carbon P! (A> is a ring-opening group of alkenyl glycidyl ethers represented by the above general formula (]I), and (B) is a ring-opening group of alkenyl glycidyl ethers represented by the above general formula (I). Represents a ring-opening group of a cyclic compound excluding alkenyl glycidyl ethers, k is an integer of 1 to 20, l is O or an integer of 1 to 20, and alkenyl glycidyl ethers represented by (A) or (B) (or the arrangement of the ring-opening groups of the cyclic compound is arbitrary.) A hydroxyl group-containing (meth)acrylate represented by (17) alone, or one obtained by polymerizing a radically polymerizable double bond together with another monobase It is.

The hydroxyl group-containing (meth)acrylate represented by the general formula (III) used in the present invention is, for example, represented by the general formula % [wherein, R is a hydrogen atom or a methyl group, and Z is a carbon number of 2 to 8]. It is a divalent organic group. Hydroxy (meth)acrylate represented by (a) The hydroxyl group of (a) is combined with the general formula [where R1 is a hydrogen atom or carbon! 720 or less) is a hydrocarbon group, and R is an alkenyl group having 20 or less carbon atoms. ] The alkenyl glycidyl ethers (b) represented by the above formula and, if necessary, a cyclic compound (c) other than the alkenyl glycidyl ethers (b) represented by the above general formula are subjected to an addition reaction.

Specific examples of hydroxy(meth)acrylate (a) include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate-1, hydroxybutyl acrylate, hydroxybutyl methacrylate, and diethyl glycol monoacrylate. , diethylene glycol monomethacrylate, hydroxycyclohexyl acrylate, hydroxycyclohexyl methacrylate, and the like. These may be used alone or as a mixture.

The compound to be avoided in the addition reaction to hydroxy(meth)acrylate (a) is selected from alkenyl glycidyl ethers (b) represented by the above general formula and, if necessary, cyclic compounds (c) excluding alkenyl glycidyl ethers (b).

Examples of the (octoday-substituted) hydrocarbon group in the alkenyl glycidyl ethers (b) include hydrocarbon groups such as alkyl groups having 20 or less carbon atoms, alkenyl groups, aryl groups, hydrogenated aryl groups, and aralkyl u, or their carbonization. Examples include halo-substituted hydrocarbon groups in which at least one hydrogen atom of the hydrogen group has been replaced with a halogen atom; of course, a halo-substituted hydrocarbon group in which all hydrogen atoms have been replaced with halogen atoms may also be used. Examples of the alkenyl glycidyl ethers (b) include vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, and the like.

Cyclic compounds (c) excluding alkenyl glycidyl ethers (b) (hereinafter abbreviated as cyclic compounds (c)).

) Examples include alkylene oxides such as ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,2-epoxydecane, 1,2-boxyhexadecane, etc.; butadiene monoxide, 1,2- Alkenyl oxides such as epoxy-5-hexene; phenylalkylene oxides such as styrene oxide; Hydrogenated aryl alkylene oxides; ε-caprolactones such as ε-caprolactone, methyl-ε-caprolactone, etc.; Te1helahydrofuran: alkyl glycidyl ethers such as methyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, etc. ; Arylglycidyl ethers such as phenylglycidyl ether, cresylglycidyl ether, etc.; Epihalohydrins such as epichlorohydrin, shrimp bromohydrin, etc.

In the general formula (1), It is the remaining base of the body. Such polymers (
Other monomers constituting a) include, for example, acrylic acids such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methacrylic acid such as methyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate; Esters; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid, or half-ester compounds of maleic acid, fumaric acid, and itaconic acid; aromatic vinyls such as styrene and vinyltoluene; acrylonitrile , unsaturated nitriles such as methacrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate;
One or a mixture of two or more body components can be used.

In addition, when it is desired to impart properties other than the low shrinkage effect, for example, impact resistance and impact mitigation properties such as hair cracks, rubber-like properties may be imparted to the obtained polymer (a).
It is desirable to use monomers that are the main component.

Such impact resistance imparting monomers have 1 to 2 carbon atoms.
Mention may be made of acrylic acid alkyl esters having 0 alkyl groups and/or methacrylic acid alkyl esters having alkyl groups having 2 to 20 carbon atoms.

Further, if necessary, as other monomers constituting the polymer (a), a bridge+unit ω monomer having two or more polymerizable double bonds in one molecule can be used. As such a monomer, commonly used crosslinking monomers such as divinyl, diallyl, diacryl, and dimethacrylic compounds can be used. Typical examples include divinylbenzene, diallyl phthalate, ethylene glycol di(meth)
Acrylate, trimedylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, triallylisocyanurate, N.

N'-methylenebis(meth)acrylamide and the like can be mentioned.

The hydroxyl group-containing (meth)acrylate polymer (a) used in the present invention is represented by the general formula (I) above, and comprises a structural unit represented by the following and a structural unit represented by 1←X→- may be combined in any order.

The numbers m and n of these constituent units combined are a positive integer for the former and O or a positive integer for the latter, and are determined by currency law according to the performance required within this range. Among them, those with m/(m+n) in the range of 0.01 to 0.9,
This is particularly preferable because it can provide a good balance between low shrinkage and improvements in mold staining and color unevenness.

The hydroxyl group-containing (meth)acrylate polymer (a) used in the present invention can be produced by various conventionally known polymerization methods. Preferably, it is prepared legally. Emulsifiers used in emulsion polymerization include anionic surfactants such as sodium dodecylbenzenesulfonate and monolithium lauryl sulfate, and nonionic surfactants such as polyoxyethylene nonylphenol ether and polyoxyethylene lauryl ether. Agents, aliphatic soaps, rosin soaps, etc. can be used alone or in combination.

As stabilizers during suspension polymerization, commonly used partially saponified polyvinyl alcohol (PVA), completely saponified P
Water-soluble polymers such as VA, carboxyl group-modified PVA, gelatin, starch, carboxymethylcellulose, polyacrylates, etc., non-Nada fine powder, anionic surfactants, nonionic surfactants, etc. are used alone or They can be used in combination.

Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, organic peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, and azobisisomer. A common polymerization initiator such as butyronitrile or a so-called redox catalyst in combination with a reducing agent can be used. Also, molecules such as alkyl mercaptans if necessary? Regulators can also be used in addition.

Further, the graft modified product (a') of the hydroxyl group-containing (meth)acrylate polymer (a) can be produced by a known method commonly used for synthesis of graft polymers,
For example, it can be obtained by polymerizing, in the presence of the polymer (a), a monomer having a double bond capable of radical polymerization with the alkenyl group in the polymer (a). As such a monomer, the same monomer as that used in obtaining the hydroxyl group-containing (meth)acrylate polymer (a) can be used.

Hydroxyl group-containing (meth)acrylate polymer (a) or its graft modified product (a') obtained by the above method
) is preferably obtained as a dry powder for blending into the thermosetting resin (b).

Separation and drying may be carried out by any known method, such as direct drying using a spray dryer or drum dryer, or coagulation through processes such as salting out, kiln drying, or freezing, followed by washing, clarification, and drying. Various separation methods, such as natural sedimentation or centrifugal sedimentation, and various drying methods, such as natural drying, reduced pressure drying, and hot air drying, can be freely combined.

In addition, the obtained polymer (a) or its graft modified product (
a') If there is strong agglomeration of W particles with each other, it is preferable to use a crushing device such as a ball mill, hammer mill, or jet mill to loosen the agglomeration.

The thus obtained hydroxyl group-containing (meth)acrylate polymer (a) or its graph 1 to modified product (a'
) has an affinity for thermosetting resin (b).

The thermosetting resin (b) used in the present invention is a radically polymerizable resin consisting of a compound having a polymerizable unsaturated group in the molecule and having a molecular age of 200 or more and a polymerizable monomer, such as Two unsaturated groups! i or a mixture of this and a saturated dibasic acid and a polyhydric alcohol are subjected to a condensation reaction at elevated temperatures in an inert gas stream, resulting in an unsaturated polyester and a polymerizable monomer represented by styrene. Unsaturated polyester resin, epoxy (meth)acrylate made by reacting (meth)acrylic acid with a polyfunctional epoxy compound, and polymerizable ψ such as styrene and methyl methacrylate-1 sudo.
Examples include vinyl ester resins consisting of m-isomers, and resins consisting of polyester (meth)acrylate or polyurethane (meth)acrylate-1- and orthotropic monom-isomers.

The low-shrinkage thermosetting resin composition of the present invention comprises a thermosetting resin (b) blended with a hydroxyl group-containing <meth)acrylate polymer (a) and/or its graft modified product (a'). However, it can be easily blended by the usual blending method when using a low-shrinkage agent. For example, a dry powder polymer (a) and/or a thermosetting resin (b) may be added to the thermosetting resin (b).
Alternatively, the graft modified product (a') thereof is directly added and stirred thoroughly, or the polymer (a) and/or the graft modified product (a') is added in advance with a monomer that can be polymerized with the thermosetting resin (b). It can be blended by adding and mixing the thermosetting resin (b) after dispersing or dissolving it in a body such as styrene.

Hydroxyl group-containing (meth)acrylate polymer (a)
And/or the blending ratio of the graft modified product (a') of A is:
A range of 1 to 40% by weight in the total of the thermosetting resin (b) and the polymer (a) and/or its graft modified product (a'),
More preferably, it is in the range of 2 to 30% by weight. 1 weight'
If the amount is less than 36, the shrinkage effect will not be sufficient;
If the weight exceeds 0% by weight, the properties of the thermosetting resin will be impaired, which is not preferable.

When curing the low-shrinkage thermosetting resin composition of the present invention, benzoyl peroxide, methyl ethyl ketone peroxide, t-butyl peroxybenzoate, t-butyl peroxy octoate, dicumyl peroxide, cumene hydroxy peroxide, Oxide, cyclohexanone peroxide, lauroyl peroxide and other organic peroxides and nitriles capable of generating radicals such as azobisisobutyronitrile and the like are used as polymerization catalysts to form a resin composition of 0.1 to 5 polymers. % range G, and if necessary, cobalt naphthenate, cobalt octenoate, manganese naphthenate, dimethylaniline, etc. are blended as a polymerization accelerator in the range of 0.1 to 5% by weight to the resin composition, This can be carried out according to conventionally known procedures.

(Effects of the Invention) The low-shrinkage thermosetting resin composition of the present invention has a hydroxyl group-containing (meth)acrylate-1-polymer (a) and/or a graft modified product thereof (a') in the composition. Since it is dissolved or dispersed extremely uniformly and stably, it has poor storage stability and can stably achieve a low shrinkage effect.

The low-shrinkage thermosetting resin composition of the present invention can be effectively used as is, but calcium carbonate, silica sand,
Fillers such as barium, clay, glass powder, etc.; Reinforcements such as glass fiber, asbestos, hemp, vinylon fiber, carbon fiber, etc. Textile material: Combined with thickeners and colorants such as magnesium oxide, magnesium hydroxide, calcium hydroxide, calcium oxide, etc., it can be used as bulk molding compound (BMC) or sheet molding compound (SMC) for Bo 1-1 septic tank, It can be used for various purposes such as toilet tanks, storage tanks, automobile parts, and electrical parts. For example, in the case of BMC, the resin composition of the present invention is mixed with calcium carbonate, magnesium oxide,
The chopped strands, coloring agent, lead stearate, and curing catalyst are mixed and charged into a mold, heated and pressed to polymerize and harden to form a molded product. In the case of SMC, the resin composition of the present invention is thoroughly mixed with a thickener, a mold release agent, a polymerization catalyst, and a filler to form a relatively viscous liquid mixture suitable for preformed glass U&F sheets. After impregnating with
The viscosity of the resin mixture is increased to such an extent that it no longer flows, forming a sheet in the form of fresh bread, which is then placed in a mold, heated and pressurized to polymerize and harden to form a molded product.

The molded product obtained in this manner has excellent surface smoothness and gloss, is free from color unevenness, and has very low molding shrinkage, so it has excellent performance such as no distortion or cracks. Another feature is that there is no mold staining during molding.

The reason why the resin composition of the present invention exhibits such excellent properties is not clear, but the reason why the resin composition of the present invention exhibits such excellent properties is that ) is thought to be due to the fact that it has two types of reactive groups, a hydroxyl group and an alkenyl group, in its molecule.

That is, this polymer (a) or its graft modified product (a')
It is thought that the above-mentioned excellent properties are exhibited because the affinity with the thermosetting resin (b) is improved due to the action of the hydroxyl group and alkenyl group contained therein.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples and self-examination examples, but these examples do not limit the present invention. Note that the parts and percentages in between are specially Unless otherwise specified, all terms refer to a part and weight ω%.

Reference Example 1 In a reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a gas introduction tube, and a manometer, 195 parts (1.5 mol) of 2-hydroxyethyl methacrylate, 0.21 part of hydroquinone monomethyl ether as a polymerization inhibitor, 2.83 parts of tungstosilicic acid was charged as a catalyst, and 513 parts (4.5 mol) of allyl glycidyl ether was added at 50°C.
After the dropwise addition took some time, the reaction was further maintained at 50° C. for 1 hour to complete the reaction. Next, 21 parts of powdered basic magnesium aluminum hydroxy carbonate hydrate, which is an adsorbent, was added, and after stirring at 60°C for 30 minutes, the pressure was removed and purification was performed to obtain a colorless transparent liquid reaction product. (Jy, lower hydroxyl group-containing methacrylate-h
It is called (1). ) 694 parts (yield 98.0%) were obtained.

As a result of analysis, the reaction product was hydroxyl group-containing methacrylate-1- having the following structure.

l-13 CI-(2=C-C00CH2C1-120-+cH2
Cl-10)-1-1CI-(2 ■蒐H2H;IH2 Reference Example 2 In a reaction vessel similar to Reference Example 1, 174 parts (1.5 mol) of 2-hydroxyethyl acrylate and hydroquinone as a polymerization inhibitor were added. Add 0.26 parts of monomethyl ether and 2.6 parts of tungstophosphoric acid as a catalyst, and bring the internal temperature to 30~30.
Allyl glycidyl ether 171 while keeping at 40℃
(1.5 mol) was added dropwise in 1 hour. After the dropwise addition was completed, the mixture was further aged at 40° C. for 1.5 hours. Next, add 174 parts (3.0 mol) of propylene oxide at 30 to 40°C.
It took 2.5 hours to drip, then another 2 hours, 40
The reaction was completed by aging at ℃. After adding 11 parts of powdered magnesium silicate, it was purified by pressure filtration and lv
511 parts of reaction product (hereinafter referred to as hydroxyl group-containing acrylate (2)) as a transparent liquid (yield 98.5%)
As a result of analysis, the reaction product was a hydroxyl group-containing acrylate with the following structure.

l-42 H l-12 Reference Example 3 400 parts of water was charged into a reaction vessel equipped with a thermometer, a stirrer, a nitrogen gas inlet tube, a flow-cooling system, and a dropping funnel, and the degree of saponification was 87 to 87 while stirring. 89 mol%, degree of polymerization 5
00 partially saponified polyvinyl alcohol was added and dissolved. Next, a monomer mixture consisting of 10 parts of the hydroxyl group-containing methacrylate (1) prepared in Reference Example 1, 1 to 89 parts of butyl methacrylate, 1 part of trimethylolpropane trimethacrylate, and 1 part of benzoyl peroxide was added thereto. After dropping the mixture and purging with nitrogen, the temperature was raised to 75°C.

The start of the reaction was confirmed by the generation of polymerization heat, and the temperature was kept at 80° for another 3 hours.
The reaction proceeded with C to obtain a suspension of hydroxyl-based fi(meth)acrylate polymer (1). m content is 99.3
%Met.

The polymer cake was removed by filtration, and the cake was
After drying for 5 hours in a hot air dryer at 0.degree. C., it was ground in a hammer mill to yield 1 q of white V) unpaid hydroxyl group-containing (meth)acrylate-1 to polymer (1) that passed through 50 meshes.

Reference Example 4 0.5 parts of sodium dodecylbenzene sulfonate, 0.4 parts of peroxyammonium, and 130 parts of deionized water were placed in a reaction vessel similar to Reference Example 3, and the inside of the reaction vessel was replaced with nitrogen while stirring. (While heating in a hot water bath to maintain the liquid temperature at 60°C, a mixture of the hydroxyl group-containing acrylate obtained in Reference Example 2 (2,110 parts, 1 to 88 parts of butyl acrylate, and 2 parts of acrylic acid) was added. 20 parts of a 1% aqueous solution of sodium bisulfite were added dropwise over 2 hours each. After the addition, the reaction solution was continued to be stirred at 60°C for 2 hours to complete the polymerization reaction, resulting in a solid content of 39.4%, p
l-13.1, viscosity (25°C, B type viscometer) 63 cps
Hydroxyl 16-containing (meth)acrylate polymer (2
) was obtained.

Next, 100 g of an aqueous dispersion of the hydroxyl group-containing (meth)acrylate polymer (2) was placed in the same reaction vessel as in Reference Example 3.
part and dodecylbenzenesulfonebutyric sodium 0.4
After adding 60 parts of an aqueous solution in which 1 part was dissolved and purging with nitrogen,
The temperature was raised to 0°C. Next, a monolayer mixture 40 for grafting consisting of 28 parts of styrene and 1 to 12 parts of 7-krylon
parts, concentration 0.5% ammonium perillate aqueous solution 2
5 parts and 1 aqueous solution of 0.5% sodium bisulfite
0 parts were continuously added dropwise under stirring over 1.5 hours each,
Solid content 34°2%, pH 2.7, viscosity (25°C, B
(type viscometer) 31 An aqueous dispersion of a graft modified product (2') of CDS was obtained. Incidentally, the proportion of the suspension mixture for grafting was 99.1%, and the grafting rate was 70%.

The obtained aqueous dispersion of the graft modified product (2') was dried on a double drum type drying oven, and then ground in a hammer mill to obtain a hydroxyl group-containing (meth)acrylate polymer (2') in the form of a white powder that passed through 50 meshes. ) is the graft modified product (2') of 14.

Example 1 50 parts of isophthalic acid, 70 parts of maleic anhydride, 34 parts of ethylene glycol and 38 parts of propylene glycol were subjected to an esterification reaction at 200°C for 24 hours in a nitrogen stream to obtain an unsaturated polyester having an acid value of 20 and an acid value of 19.

40.6 parts of this unsaturated polyester and 50.4 parts of styrene
parts were blended to obtain an unsaturated polyester resin (hereinafter referred to as unsaturated polyester resin (1)).

Next, 9 parts of the hydroxyl group-containing (meth)acrylate polymer (1) prepared in Reference Example 3 was mixed with 100 parts of this unsaturated polyester resin m, and the low-shrinkage thermosetting resin composition of the present invention ( Hereinafter, this will be referred to as resin composition (1).

) was obtained.

To the obtained resin composition (1), 1 part of t-butyl peroxybenzoate, 3 parts of zinc stearate, blue toner (manufactured by Sumika Color Flavor, KP-5E326) and 100 parts of calcium carbonate were added and stirred to form a paste. did. Furthermore, using an impregnating solution obtained by mixing 1.0 part of magnesium oxide with this paste, 70.7 parts of glass fiber with a length of 25 mm was impregnated, formed into a sheet between two polyethylene sheets, and held at 40°
It was aged at C for 40 hours and converted into S to IC. This SMC was press-molded for 4 minutes in a mold with a size of 300 mm x 300 mm under the following molding conditions: 140°C, 50K9/ci, to form a flat plate molded product with a thickness of 2 tmm. . The molding shrinkage rate of this S~1C is JIS K
6911, the shrinkage was 0.07%. In addition, the gloss of the surface of the molded product was evaluated using a surface gloss meter by calculating the reflectance (%) at a measurement angle of 60 degrees, and it was found to be 84.8%. Furthermore, we visually observed the uneven color of the molded product and the dirt on the mold.
There is no color unevenness at all, and the molded product has excellent surface smoothness.
There was no mold staining at all.

Example 2 In place of the hydroxyl group-containing (meth)acrylate-1-polymer (1) in Example 1, I'? in Reference Example 4 was used. It is lζ
Hydroxyl group-containing (meth)acrylate hand coalescence (2)
The low shrinkage thermosetting resin composition of the present invention (hereinafter referred to as resin composition (2)) was prepared in the same manner as in Example 1 except that the graft modified product (2') of Ta.

Using the obtained resin composition (2), it was made into SMC in the same manner as in Example 1, and a molded article was further produced. Performance was evaluated in the same manner as in Example 1. As a result, the molding yield wU was 0.05%,
The gloss was 86.2%.

Further, when the molded product was visually observed for color unevenness and mold staining, it was found that there was no color unevenness at all, the molded product had excellent surface smoothness, and there was no mold staining at all.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I) [However, in the formula, R is a hydrogen atom or a methyl group, and Z
represents a divalent organic group having 2 to 8 carbon atoms, (A) is a ring-opening group of alkenyl glycidyl ethers represented by the following general formula (II), and (B) is a ring-opening group of alkenyl glycidyl ethers represented by the following general formula (II). represents a ring-opening group of a cyclic compound excluding alkenyl glycidyl ethers, k is an integer of 1 to 20, l is 0 or 1 to
20, and the arrangement of the ring-opening groups of the alkenyl glycidyl ethers or cyclic compounds represented by (A) and (B) is arbitrary; Residues, m is a positive integer, n is 0
or indicates a positive integer. ) A low-shrinkage thermosetting resin composition comprising a hydroxyl group-containing (meth)acrylate polymer (a) and/or its graft modified product (a') and a thermosetting resin (b). thing. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼(II) [In the formula, R^1 is a hydrogen atom or a (halo-substituted) hydrocarbon group having 20 or less carbon atoms, and R^2 is a hydrogen atom or a (halo-substituted) hydrocarbon group having 20 or less carbon atoms. It is an alkenyl group. 2. The low-shrinkage thermosetting resin composition according to claim 1, wherein the alkenyl glycidyl ether is allyl glycidyl ether. 3. A patent claim in which the cyclic compound other than alkenyl glycidyl ethers is one or more compounds selected from the group consisting of alkylene oxide, ε-caprolactones, tetrahydrofuran, alkyl glycidyl ether, aryl glycidyl ether, and epihalohydrin. A low-shrinkage thermosetting resin composition according to item 1 or 2. 4. The low shrinkage thermosetting resin composition according to claim 1, 2 or 3, wherein m/(m+n) is 0.01 to 0.9.