JP3238586B2 - Low-shrinkage agent composition for unsaturated polyester resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-shrinkage agent composition for unsaturated polyester resins, and more particularly, it has improved compatibility with unsaturated polyester resins and workability during thickening, and has a good appearance. The present invention relates to a styrene copolymer low-shrinkage agent composition from which a molded product can be obtained.

[0002]

2. Description of the Related Art Unsaturated polyester resins are used in a wide range of fields as raw materials for fiber reinforced plastics (FRP). Since the unsaturated polyester resin itself has a very large shrinkage ratio of 5 to 12% upon curing,
The molded product is warped, glossy, wavy, cracked, and the like. On the other hand, as a means for reducing the shrinkage, it is common to blend a thermoplastic resin such as polyvinyl acetate, polymethyl methacrylate, polyethylene, and polystyrene into an unsaturated polyester resin, and these thermoplastic resins are used. Is said to be a low shrinkage agent.

Depending on whether they are completely dissolved when they are mixed with the unsaturated polyester resin or whether they are dispersed in the unsaturated polyester resin in the form of droplets, the low-shrinkage agent can be used in a compatible system (homogeneous system). ) And incompatible (dispersed). Among them, polyvinyl acetate, polymethyl methacrylate and the like are compatible systems and have a sufficient low shrinkage effect, but have a drawback that the mechanical strength of the molded product is low.

On the other hand, conventionally used polyethylene, polystyrene and the like are incompatible systems, and the resulting molded product has excellent characteristics such as good colorability and pigment dispersibility, and high mechanical strength. However, for example, when an unsaturated polyester resin is blended with polystyrene as a low-shrinking agent and magnesium oxide (MgO) as a thickening agent to prepare a sheet molding compound (SMC) and obtain a molded product, the polystyrene becomes unsatisfactory. Since it does not mix with the saturated polyester resin, the following two problems occur. That is, in the so-called thickening step of forming a metal bridge between the carboxyl group of the unsaturated polyester resin and magnesium oxide, in the so-called thickening step, the unsaturated polyester resin and polystyrene cause phase separation, and when the thickened sheet is peeled off. Stringing and stickiness occur in the fabric. The so-called scumming, in which the polystyrene in the unsaturated polyester resin separates and emerges on the surface of the molded product and significantly impairs its appearance, and the separated polystyrene contaminates the mold surface and hinders mold release.
ng) causes the phenomenon.

[0005] In order to prevent these, it has been attempted to use a styrene-based polymer having a carboxyl group introduced as a low-shrinking agent (Eiichiro Takiyama, Handbook of Polyester Resins, 633-636, Nikkan Kogyo Shimbun (1988)). Described). This is intended to form a metal oxide bond between the carboxyl group of the polymer and that of the unsaturated polyester resin. However, the obtained polymer is a mixture ranging from a styrene copolymer containing a large amount of carboxyl groups to a polystyrene not containing the same, and the effect of the copolymer is very small. Insufficient.

The present invention maintains the excellent characteristics of the conventional incompatible low-shrinkage agent, namely, that the molded product has good colorability and pigment dispersibility, high mechanical strength, and a high viscosity. An object of the present invention is to improve the peelability of the sheet afterward and to obtain a molded article having a good appearance without causing a scumming phenomenon.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, styrene, (meth) acrylate, and a polymer having a carboxyl group as a low-shrinking agent. The fact that it is effective to use a styrene-based polymer obtained by terminating a specific monomer composition at a specific polymerization rate with a specific ratio of three components of a hydrophilic monomer has led to the present invention. . It is considered that the reason why the polymer obtained under such conditions exerts a sufficient effect is that the copolymer containing a carboxyl group in the polymer has little variation and is uniform.

That is, the present invention comprises a total of 100% by weight of 65 to 98.9% by weight of styrene, 1 to 25% by weight of a (meth) acrylate, and 0.1 to 10% by weight of a polymerizable monomer having a carboxyl group. With respect to 100 parts by weight of the monomer composition, 0.01 to 1 part by weight of a chain transfer agent is added and bulk polymerization is performed.
It is obtained by terminating polymerization at a polymerization rate of 10 to 70%, and has an acid value of 0.1 to
A low-shrinkage agent composition for an unsaturated polyester resin, which has a uniform copolymer composition of 50 mg-KOH / g. In addition, in this specification, (meth) acrylic acid ester and (meth) acrylic acid mean methacrylic acid ester, acrylic acid ester; methacrylic acid, acrylic acid.

In the present invention, any (meth) acrylic ester may be used as long as it is commonly used. For example, ethyl (meth) acrylate, (meth)
Methyl acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like. One type can be used. The amount of the (meth) acrylate is preferably in the range of 1 to 25% by weight in the three-component monomer composition containing the styrene and the polymerizable monomer having a carboxyl group. If this amount is less than 1% by weight, the compatibility with the unsaturated polyester resin is poor, the low-shrinkage agent separates during thickening, and the surface of the molding die is contaminated, and the appearance of the molded product is not good. If it exceeds 25% by weight, the compatibility between the unsaturated polyester resin and the low-shrinkage agent increases, and the low-shrinkage effect of the molded product is remarkably deteriorated.

In the present invention, examples of the polymerizable monomer having a carboxyl group include (meth) acrylic acid,
Carboxyl groups, such as maleic acid and itaconic acid,
Any one having a double bond capable of radical polymerization can be used. The polymerizable monomer having a carboxyl group is styrene and (meth)
In a three-component monomer composition containing an acrylate ester, 0.1.
A range of 1 to 10% by weight is preferred. When this amount is less than 0.1% by weight, the resulting polymer has a small amount of carboxyl groups, the low-shrinkage agent separates at the time of thickening, and the mold surface is contaminated, and the appearance of the molded product is not good. If it exceeds 10% by weight, the polymer is precipitated during the polymerization, so that it is not suitable for a low-shrinking agent.

The bulk polymerization of styrene in the present invention is carried out in a reaction vessel in an atmosphere of an inert gas such as nitrogen at normal pressure or pressure.
Thermal radicals generated by heating a monomer composition comprising styrene and the above two components, and / or 2,2'-azobisisobutyronitrile (hereinafter abbreviated as AIBN), benzoyl peroxide, and the like A known radical polymerization initiator such as described above is added to the monomer composition, and the polymerization is started by a radical generated from the polymerization initiator. At this time, the polymerization temperature is usually 50 to 220 ° C, preferably 80 to 150 ° C. Also,
In the above bulk polymerization, by adding a chain transfer agent, the molecular weight of the obtained styrene-based polymer is 5,000 to
Adjust between 500,000. Any chain transfer agent may be used as long as it is generally used for polymerization or copolymerization of radically polymerizable monomers. For example, methyl mercaptan, t-butyl mercaptan, decyl mercaptan,
Mercaptans such as benzyl mercaptan, lauryl mercaptan, stearyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid; methanol, propanol, butanol, isobutanol, t-butanol, hexanol, benzyl alcohol, allyl alcohol And halogenated hydrocarbons such as chloroethane, fluoroethane, trichloroethylene and carbon tetrachloride. Among them, ease of molecular weight adjustment,
Further, when the obtained styrenic polymer and unsaturated polyester resin are blended and cured, mercaptans are preferred from the viewpoint of improving the compatibility of both and not hindering the curing, and n-dodecyl mercaptan ( Hereinafter, n-
Abbreviated as DM. Is more preferred. This chain transfer agent is
It may be charged into the reaction vessel at a time before the polymerization, or may be added continuously or sequentially during the polymerization.

The amount of the chain transfer agent in the present invention is usually 0.01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of styrene. If this amount is less than 0.01 part by weight, the viscosity of the polymerization system becomes high, so that it becomes difficult to manufacture or the workability when impregnating the reinforcing material with the composition of the obtained composition and the unsaturated polyester resin is reduced. I do. Further, the mold surface is contaminated, and the appearance of the molded product is not good. On the other hand, if this amount exceeds 1 part by weight, the molecular weight of the obtained styrene-based polymer decreases, so that the compatibility between the unsaturated polyester resin and the low-shrinkage agent increases, and the low-shrinkage effect of the molded product is remarkably reduced. Getting worse.

In the present invention, the degree of polymerization of styrene is 1
When it reaches 0-70%, the polymerization is stopped. If the degree of polymerization is less than 10%, the amount of the styrene-based polymer which is effective in reducing the shrinkage of the molded product will be small, and if it exceeds 70%, the viscosity of the polymerization system will be high. By the way, by stopping the polymerization, a large amount of unreacted styrene remains in the resulting styrene-based polymer, but this is not inconvenient at all, and the work involved in blending this composition with the unsaturated polyester resin This is advantageous because the property is improved.

As a method for terminating the polymerization, any known method may be used as long as the chain transfer of the growing radical is stopped and disappears. To do so, add 50 to 5,0
The operation is performed by adding a 00 ppm polymerization terminator, blowing oxygen or air into the polymerization solution, cooling the polymerization solution to 40 ° C. or lower, and these may be used alone or in combination of two or more.

Here, the polymerization terminator quickly reacts with styrene and / or radicals generated from the polymerization initiator,
An agent that converts into a stable radical or neutral substance that does not subsequently cause polymerization. Specific examples thereof include quinones such as p-benzoquinone, naphthoquinone, phenanthraquinone, and 2,5-diphenyl-p-benzoquinone; hydroquinone, pt-butylcatechol, and 2,5-di-t-butylhydroquinone. Hydroquinones such as mono-t-butylhydroquinone and 2,5-di-t-butylhydroquinone; phenols such as di-t-butylparacresol hydroquinone monomethyl ether and α-naphthol;
Organic and inorganic copper salts such as copper naphthenate; amidines such as acetamidine acetate and acetamidine sulfate;
Hydrazine salts such as phenylhydrazine hydrochloride and hydrazine hydrochloride; quaternary ammonium salts such as trimethylbenzylammonium chloride, laurylpyridinium chloride, cetyltrimethylammonium chloride and phenyltrimethylammonium chloride; polyhydric phenols such as pyrogallol, tannic acid and resorcinol : Nitro compounds and oximes.

The styrene-based polymer composition obtained by terminating the polymerization as described above has an acid value of 0.1 to 50 mg-
KOH / g, preferably in the range of 0.1-20 mg-KOH / g.
When the acid value is less than 0.1 mg-KOH / g, the resulting polymer has a small number of carboxyl groups, the low-shrinkage agent separates at the time of thickening, and the mold surface is contaminated, and the appearance of the molded product is poor. On the other hand, if it exceeds 50 mg-KOH / g, the polymer is precipitated during the polymerization, so that it is not suitable for a low shrinkage agent.

The unsaturated polyester resin in the present invention is a normal unsaturated polyester resin, and may be α, β-
Unsaturated carboxylic acids and polyhydric glycols, or α, β-
It can be easily obtained by polycondensing unsaturated carboxylic acids, polyvalent saturated carboxylic acids and polyhydric glycols, and dissolving them in styrene and / or methyl methacrylate. When these are polycondensed, a known esterification catalyst such as dibutyltin oxide may be used.

Here, examples of the α, β-unsaturated carboxylic acid include maleic anhydride, maleic acid, fumaric acid,
One type or a mixture of two or more types selected from tetraconic acid, itaconic acid, and their alkyl esters. As the polyvalent saturated carboxylic acid, for example,
Phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride, heptanoic acid, succinic acid,
One type or a mixture of two or more types selected from adipic acid, sebacic acid and their alkyl esters.

Examples of polyhydric glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, Dibromoneopentyl glycol, 1,6-hexanediol; alkyl oxide adducts of bisphenol A or bisphenol F such as ethylene oxide or propylene oxide, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated bisphenol A or ethylene oxide of hydrogenated bisphenol F Or alkyl oxide adducts such as propylene oxide; divalent glycols such as pentaerythritol diallyl ether; trivalent glycols such as trimethylolpropane One type chosen, or a mixture of two or more thereof.

In the present invention, the obtained styrenic polymer composition is used as a low-shrinking agent by mixing 2 to 100 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin. The low-shrinkage agent composition and the unsaturated polyester resin include a thickener such as magnesium oxide, a stabilizer,
Filler, reinforcing material, thickener, release agent, pigment, etc.
A sheet molding compound (hereinafter abbreviated as SMC) or a bulk molding compound (hereinafter abbreviated as BMC) with good workability can be manufactured. At this time, the amount of the thickener is based on 100 parts by weight of the total amount of the unsaturated polyester resin and the low-shrinkage agent composition.
0.1 to 5 parts by weight. The obtained compound can be made into a target molded product by heat compression molding, injection molding, transfer molding or the like.

In addition, the low-shrinkage agent composition of the present invention is not limited to SMC or BMC, and the compatibility with unsaturated polyester resin is greatly improved as compared with that of conventional polystyrene. Unsaturated polyester resin and, if necessary, a curing agent, a curing accelerator, a stabilizer, a filler, a reinforcing material, a release agent, a pigment, a flame retardant, and the like are appropriately blended, and a known molding method, for example, The desired molded product can be obtained by hand lay-up molding, spray-up molding, resin injection molding, cold press molding, matched die molding, pultrusion molding, and filament winding molding.

[0022]

The present invention will be described in detail below with reference to examples and comparative examples. In the following, “parts” are based on weight.

Example 1 A glass four-necked flask (with a stirrer, an external heater, a cooling tube, a thermometer and a nitrogen introducing tube) was charged with 93 parts of styrene, 5 parts of methyl methacrylate, 2 parts of methacrylic acid and n-DM.
Add 0.25 part, and stir under nitrogen stream from room temperature to 100
Heated to C over 1 hour. 100 ° C over 1 hour
To 130 ° C., and the polymerization was carried out at intervals of 20 minutes while measuring the conversion by the non-volatile content method. When the polymerization rate exceeds 40%, dry air is blown into the polymerization liquid and cooling is started, the temperature is lowered to 80 ° C, 0.03 parts of a polymerization terminator hydroquinone is charged, and the temperature is further cooled to 10 ° C or less. The polymerization was stopped to obtain a low-shrinkage agent composition. The polymerization rate of this composition is 41.6%, its viscosity is 31 poise and its acid value is 13.4
mg-KOH / g. These are summarized in Table 1. next,
Using this low-shrinkage agent composition, SMC was prepared with the following composition. Unsaturated polyester resin 70 parts (trade name: Ester ML1815, resin for mold molding, manufactured by Mitsui Toatsu Chemicals, Inc.) Low shrinkage agent composition 30 parts Calcium carbonate 150 parts Zinc stearate 5 parts t-butyl perbenzoate 1.5 parts Glass Fiber (6mm length, chopped strand) 167 parts Magnesium oxide 2 parts Black pigment 2 parts This SMC is thickened at 40 ° C for 24 hours, aged, and then press-molded (temperature 140 ° C, pressure 100Kg / cm ² , time) 5 minutes) to obtain a molded plate (300 mm × 300 mm × 3 mm thick).

The obtained SMC and molded plate were evaluated by the following methods, and the results are shown in Table 1. -Sheet peelability: After thickening this SMC, the workability when peeling the sheet adhered to the SMC was evaluated in three stages.・ ・ ・: Good workability without stickiness at all △: Slightly sticky with some stickiness and slightly poor workability ×: Slightly sticky overall and poor workability ・ Die contamination: After press-molding this SMC, the surface of the mold was visually evaluated in three stages. ○ ・ ・ ・ The surface of the mold is not contaminated with resin at all △ ・ ・ ・ Part of the mold is contaminated with resin × ・ ・ ・ The entire surface of the mold is contaminated with resin ・ Molded product Appearance: The appearance of this molded plate was visually evaluated in three stages. ○ ・ ・ ・ Smooth surface and gloss △ ・ ・ ・ Surface partially extruded and slightly glossy × ・ ・ ・ Waviness occurred and overall lack gloss ・ Mold shrinkage: JIS-K- Based on 6911, a disc (90 mm in diameter × 11 mm in thickness) was press-molded from this SMC, and the molding shrinkage was determined.

Example 2 The same procedure as in Example 1 was repeated except that the amount of styrene was changed to 75 parts, the amount of methyl methacrylate was changed to 20 parts, and the amount of methacrylic acid was changed to 5 parts. A composition was obtained. The polymerization rate of this composition was 41.7%, its viscosity was 35 poise and its acid value was 33.1 mg-KOH / g. Thereafter, in the same manner as in the latter half of Example 1, an SMC was prepared using this composition to obtain a molded plate, which was evaluated. Table 1 shows the results.

Example 3 In the same flask used in Example 1, styrene 89 was added.
Parts, methyl acrylate 10 parts, maleic acid 1 part and n-D
0.2 parts of M
Heated to 00 ° C. over 1 hour. 100 more hours
The mixture was heated from 130 ° C. to 130 ° C., and polymerized at intervals of 20 minutes while measuring the conversion by the non-volatile content method. When the polymerization rate exceeds 30%, dry air is blown into the polymerization liquid and cooling is started.The temperature is lowered to 80 ° C, 0.03 part of a polymerization terminator hydroquinone is added, and the temperature is further cooled to 10 ° C or less. The polymerization was stopped to obtain a low-shrinkage agent composition. This composition has a polymerization rate of 31.9%, a viscosity of 22 poise and an acid value of 5.1.
mg-KOH / g. Thereafter, in the same manner as in the latter half of Example 1, an SMC was prepared using this composition to obtain a molded plate, which was evaluated. Table 1 shows the results.

Example 4 97.3 styrene was added to the same flask used in Example 1.
Parts, 2 parts of ethyl acrylate, 0.7 parts of acrylic acid and n-
Add 0.5 part of DM and stir from room temperature under nitrogen flow
Heated to 100 ° C. over 1 hour. 1 more hour
The mixture was heated from 00 ° C to 130 ° C, and polymerized at intervals of 20 minutes while measuring the conversion by the non-volatile method. When the polymerization rate exceeds 45%, dry air is blown into the polymerization liquid and cooling is started, the temperature is lowered to 80 ° C, 0.03 part of a polymerization terminator hydroquinone is added, and the temperature is further cooled to 10 ° C or less. The polymerization was stopped to obtain a low-shrinkage agent composition. The conversion of this composition is 45.5%, its viscosity is 30 poise and its acid value is
It was 7.7 mg-KOH / g. Thereafter, in the same manner as in the latter half of Example 1, an SMC was prepared using this composition to obtain a molded plate, which was evaluated. Table 1 shows the results.
Shown in

Example 5 Into the same flask used in Example 1, styrene 92 was added.
Parts, methyl acrylate 5 parts, acrylic acid 3 parts, AIBN
0.1 part and 0.5 part of t-dodecylmercaptan (abbreviated as t-DM) are added, and the mixture is heated from room temperature to 70 ° C. for 1 hour with stirring under a nitrogen stream, and is maintained at an interval of 20 minutes. The polymerization was carried out while measuring the conversion by the method.
When the degree of polymerization exceeds 25%, dry air is blown into the polymerization solution and cooling is started, and the polymerization terminator hydroquinone is used.
0.03 parts were added, the mixture was cooled to 10 ° C. or lower, and the polymerization was stopped to obtain a low-shrinkage agent composition. The conversion of this composition is 27.
1%, its viscosity is 33 poise and its acid value is 19.2 mg-KO
H / g. Thereafter, in the same manner as in the latter half of Example 1, an SMC was prepared using this composition to obtain a molded plate, which was evaluated. Table 1 shows the results.

Example 6 In the same flask used in Example 1, styrene 80
Parts, methyl methacrylate 10 parts, methyl acrylate 7 parts,
3 parts of methacrylic acid and 0.5 part of n-DM were added, heated and kept from room temperature to 70 ° C. for 1 hour with stirring under a nitrogen stream, and 0.1 part of AIBN was added to initiate polymerization. The mixture was further heated to 110 ° C. over 1 hour with stirring under a nitrogen stream, and polymerized at intervals of 20 minutes while measuring the conversion by the non-volatile content method. When the conversion exceeds 30%, dry air is blown into the polymerization liquid and cooling is started.
The temperature is lowered to 0 ° C and the polymerization terminator hydroquinone 0.03
Then, the mixture was cooled to 10 ° C. or lower, and the polymerization was stopped to obtain a low-shrinkage agent composition. The conversion of this composition is 32.2%,
Its viscosity is 30 poise and its acid value is 20.1 mg-KOH / g
Met. Thereafter, in exactly the same manner as in the latter half of Example 1, an SMC was prepared using this composition, and a molded plate was obtained.
This was evaluated. Table 1 shows the results.

[0030]

[Table 1]

Comparative Example 1 In the first half of Example 2, when the polymerization rate exceeded 5%, dry air was blown into the polymerization solution and cooling was started.
The temperature is lowered to 0 ° C and the polymerization terminator hydroquinone 0.03
The mixture was further cooled to 10 ° C. or lower, and the polymerization was terminated to obtain a low-shrinkage agent composition. The conversion of this composition is 7.0
%, Its viscosity is 3.1 poise and its acid value is 13.3 mg-KOH /
g. Thereafter, in the same manner as in the latter half of Example 1, an SMC was prepared using this composition to obtain a molded plate, which was evaluated. Table 2 shows the results.

Comparative Example 2 In the first half of Example 1, the same operation was carried out except that the polymerization was not terminated even if the conversion exceeded 40%. When the degree of polymerization exceeded 70%, the viscosity of the polymerization solution became extremely high, stirring was impossible, and the composition could not be obtained.

Comparative Example 3 The same procedure as in Example 2 was repeated except that the amount of n-DM was changed to 1.5 parts to obtain a low-shrinkage agent composition. The degree of polymerization of this composition is 31.2% and its viscosity is 11 p
oise and its acid value were 5.2 mg-KOH / g. Thereafter, in the same manner as in the latter half of Example 1, an SMC was prepared using this composition to obtain a molded plate, which was evaluated.
Table 2 shows the results.

Comparative Example 4 In the first half of Example 2, the same operation was carried out except that n-DM was not used. Before the degree of polymerization reached 30%, the viscosity of the polymerization solution became extremely high, stirring was impossible, and the composition could not be obtained.

Comparative Example 5 In the first half of Example 1, low shrinkage was performed in exactly the same manner except that 93 parts of styrene were changed to 85 parts and 50 parts of methyl methacrylate were changed to 15 parts, and methacrylic acid was not used. An agent composition was obtained. The polymerization rate of this composition was 40.8%, its viscosity was 30 poise and its acid value was 0.1 mg-KOH / g. Thereafter, in the same manner as in the second half of the first embodiment,
An SMC was prepared using this composition to obtain a molded plate, which was evaluated. Table 2 shows the results.

COMPARATIVE EXAMPLE 6 The procedure was the same as in Example 1, except that 93 parts of styrene were changed to 75 parts, 5 parts of methyl methacrylate to 10 parts, and 2 parts of methacrylic acid to 15 parts. did. When the conversion exceeds 5%, a polymer precipitates out,
It could not be compounded, molded and evaluated as a low shrinkage agent.

COMPARATIVE EXAMPLE 7 Exactly the same as in the first half of Example 1 except that 93 parts of styrene were changed to 68 parts, 5 parts of methyl methacrylate to 30 parts, and 2 parts of methacrylic acid to 2 parts of acrylic acid. Operated. The polymerization rate of this composition was 41.6%, its viscosity was 27 poise and its acid value was 13.2 mg-KOH / g. Thereafter, in the same manner as in the latter half of Example 1, an SMC was prepared using this composition to obtain a molded plate, which was evaluated. Table 2 shows the results.

[0038]

[Table 2]

[0039]

According to the present invention, the compound containing the obtained low-shrinkage agent composition and the unsaturated polyester resin as the main components has good sheet releasability after thickening. The molding surface is not contaminated, and the molded product has a low shrinkage ratio and has a good appearance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08F 220: 02 C08F 220: 02 222: 02) 222: 02) (72) Inventor Hideo Arikawa 1900 Togo, Togo, Mobara City, Chiba Prefecture Higashi Mitsui Examiner at Toshikagaku Co., Ltd. Takayuki Harada (56) References JP-A-7-150024 (JP, A) JP-A-61-123857 (JP, A) JP-A-49-31791 (JP, A) JP-A-49-34995 (JP, A) JP-A-52-28589 (JP, A) JP-A-7-150023 (JP, A) JP-A-61-275314 (JP, A) JP-A-55-21460 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 2/02 C08F 212/08-212/10 C08F 220/02-220/40 C08F 222/02-222/28 C08L 25 / 08-25/14 C08L 67/06-67/07

Claims (1)

(57) [Claims] 1. A monomer composition comprising a total of 100% by weight of 65 to 98.9% by weight of styrene, 1 to 25% by weight of a (meth) acrylate, and 0.1 to 10% by weight of a polymerizable monomer having a carboxyl group. Chain transfer agent 0.0
It is obtained by bulk polymerization by adding 1 to 1 part by weight, polymerization is terminated at a polymerization rate of 10 to 70%, acid value is 0.1 to 50 mg-KOH / g, and it has a uniform copolymer composition And a low-shrinkage agent composition for unsaturated polyester resins.