JPH07109332A - Production of vinylester resin and resin composition for artificial marble - Google Patents

Abstract

PURPOSE:To obtain a vinylester resin excellent in hot water resistance and heat resistance and useful for artificial marbles, etc., without causing the change in the appearance even if exposed on long-term hot water or high temperature by reacting an epoxy resin with an unsaturated monobasic acid under specific conditions. CONSTITUTION:This vinylester resin is obtained by reacting (A) an epoxy resin such as bisphenol A type epoxy resin with (B) an unsaturated monobasic acid such as an acrylic acid in the presence of a phenolic compound of formula I {[X, Y and Z are H or formula II [R1 and R2 are alkyl; (n) is l-10] with the proviso that one or more groups among X, Y and Z are formula II}, e.g., 2,6-(dimethylaminomethyl)phenol or an organic acid salt of this phenolic compound and a polymerization inhibitor such as hindered phenol. Furthermore, this resin composition for artificial marble is obtained by using the resin, a compound having an ethylenic unsaturated double bond and an inorganic filler as essential components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a vinyl ester resin which can be a cured product having excellent hot water resistance and heat resistance,
And a resin composition for artificial marble which is excellent in hot water resistance and heat resistance and is useful for bathtubs, countertops, and the like.

[0002]

2. Description of the Related Art At present, as a resin for artificial marble, a so-called vinyl ester resin obtained by modifying an epoxy resin with (meth) acrylic acid is excellent in hot water resistance, and a cured product thereof has a refractive index of that of an artificial marble. This is being studied because it is possible to obtain an artificial marble that is close to the refractive index of aluminum hydroxide or glass powder used as a filler and has excellent transparency. However, the vinyl ester resin is excellent in hot water resistance, so that swelling and cracking are small, but it has a drawback that it is easily discolored by hot water or heat.

Therefore, conventionally, for example, Japanese Unexamined Patent Publication No. 5-155
No. 954, a light-colored vinyl ester obtained by reacting an epoxy resin with (meth) acrylic acid in the presence of phosphorous acid and / or a phosphorous acid diester, as an artificial marble resin that is less discolored by hot water or heat. Techniques using resins are disclosed.

[0004]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
As described in JP-A-155954, the technique of using a light-colored vinyl ester resin produced by using phosphorous acid or a phosphorous acid diester is not only insufficient in the effect of preventing discoloration against hot water or heat, but also curability is impaired. However, there is a problem that blisters and cracks due to hot water are likely to occur.

The problem to be solved by the present invention is a vinyl ester resin which does not change its appearance such as discoloration, whitening, swelling and cracks even when the cured product is exposed to hot water or high temperature for a long time. Another object of the present invention is to provide a resin composition for artificial marble which is excellent in hot water resistance and heat resistance.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a vinyl ester resin is produced by using a specific esterification catalyst and a specific polymerization inhibitor. It has been found that a vinyl ester resin having excellent hot water resistance and heat resistance that does not cause a change in appearance such as discoloration, whitening, swelling, and cracking even when exposed to hot water or high temperature for a long time is obtained. Has been completed.

That is, in the present invention, the epoxy resin (a-1) and the unsaturated monobasic acid (a-2) are used as the phenol compound (b-1) having an aliphatic tertiary amino group in the aromatic nucleus or the A method for producing a vinyl ester resin characterized by reacting in the presence of an organic acid salt (b-2) of a phenolic compound and a polymerization inhibitor (c), and an epoxy resin (a-
1) and an unsaturated monobasic acid (a-2), and a phenolic compound (b-1) having an aliphatic tertiary amino group in an aromatic nucleus or an organic acid salt (b-2) of the phenolic compound. For artificial marble, which comprises a vinyl ester resin obtained by reacting in the presence of a polymerization inhibitor (c), a compound having an ethylenically unsaturated double bond, and an inorganic filler as essential components. It relates to a resin composition.

First, as the epoxy resin (a-1) used in the present invention, for example, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a brominated bisphenol A type epoxy resin, or an alkylene oxide adduct of bisphenol A is used. Bisphenol type epoxy resins such as glycidyl ether; phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol novolac type epoxy resins, naphthalene novolac type epoxy resins and other novolac type epoxy resins; dipropylene glycol diglycidyl ether, trimethylolpropane tri Glycidyl ethers of polyhydric alcohols such as glycidyl ether; 3,4-
Epoxy-6-methylcyclohexylmethyl-3,4-
Epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-3,4-
Alicyclic epoxy resins such as epoxycyclohexanecarboxylate, 1-epoxyethyl-3,4-epoxycyclohexane; phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, diglycidyl p-oxybenzoic acid, dimer acid glycidyl ester, etc. Glycidyl esters; tetraglycidyl diaminodiphenylmethane, tetraglycidyl m-xylylenediamine, triglycidyl P-aminophenol, N, N
-Glycidyl amines such as diglycidyl aniline;
Heterocyclic epoxy resins such as 1,3-diglycidyl-5,5-dimethylhydantoin and triglycidyl isocyanurate; 2,2 ', 4,4'-tetraglycidoxybiphenyl, dimethylbisphenol C diglycidyl ether, bis- Examples include β-trifluoromethyldiglycidyl bisphenol A and the like. These resins may be used alone or in combination of two or more. Among these, a bisphenol type epoxy resin and a novolac type epoxy resin are preferable because the vinyl ester resin obtained in particular has excellent heat resistance.

Examples of the unsaturated monobasic acid (a-2) include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, acrylic acid dimer, monomethylmalate, monopropylmalate, monobutylmalate, Examples include mono (2-ethylhexyl) malate and sorbic acid. These acids may be used alone or in combination of two or more kinds.

The mixing ratio of the epoxy resin (a-1) and the unsaturated monobasic acid (a-2) is not particularly limited, but is usually 1.0 equivalent to the epoxy group of the resin. ,
The range of 0.8 to 1.2 moles of acid is preferred.

In the present invention, the phenolic compound (b-1) or its organic acid salt (b-2) comprises an epoxy resin (a-1) and an unsaturated monobasic acid (a-2). Efficiently promotes the esterification reaction and acts as an esterification catalyst to suppress other side reactions, and the polymerization inhibitor (c) is essential for preventing gelation of the finished vinyl ester resin during storage. It is an ingredient.

As the phenolic compound (b-1),
It is not particularly limited as long as it has an aliphatic tertiary amino group in the aromatic nucleus, and examples thereof include those represented by the following general formula (1).

[0013]

[Chemical 5]

(X, Y, and Z are hydrogen atoms or those represented by the following general formula (2). In the general formula (2), R ₁ and R ₂ are alkyl groups, and n is 1 to 10). And at least one of X, Y and Z is represented by the general formula (2).)

[0015]

[Chemical 6]

Such a phenolic compound (b-1)
Typical examples thereof include 2,6- (dimethylaminomethyl) phenol and 2,4,6-tris (dimethylaminomethyl) phenol. Of these, 2,4,6-tris (dimethylaminomethyl) phenol is preferable because the effect of the present invention is more remarkable.

Further, the above phenolic compound (b-1)
The organic acid salt (b-2) is not particularly limited, and examples thereof include monoethylhexoate, monoacetate, monobenzoate, diethylhexoate, diacetate, diacetate of the above-mentioned various phenolic compounds. Examples thereof include benzoate, triethylhexoate, triacetate, tribenzoate and the like.

In the present invention, by using the above-mentioned phenolic compound (b-1) and its organic acid salt (b-2) as a reaction catalyst, discoloration occurs even when exposed to hot water or high temperature for a long time, It is possible to suppress appearance changes such as whitening, blistering, and cracks. In addition, phenolic compounds (b
When -1) and its organic acid salt (b-2) are compared, (b-1) is preferable because the reaction rate is further increased.

The amount of the phenolic compound (b-1) or its organic acid salt (b-2) used is not particularly limited, but usually the epoxy resin (a-1) and the unsaturated monobasic acid are used. 0.01 to 3 relative to the total weight with (a-2).
The range of 0% is preferable, and the range of 0.05 to 2.0% is preferable from the viewpoint of more excellent effect of preventing discoloration of the cured product.

As the polymerization inhibitor (C), any known and commonly used one can be used and is not particularly limited, but it has both an effect of preventing gelation and an effect of preventing discoloration of a cured product, In addition, since the effect is more remarkable, so-called
Hindered phenols are preferred.

As the hindered phenol, for example,
2,6-ditertiary butylphenol, 2,4-dimethyl-6-tertiarybutylphenol, 2,6-ditertiarybutyl-4-methylphenol, octadecyl-3- (3 , 5-ditertiarybutyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis (4-methyl-6-tertiarybutylphenol,
4,4'-methylene-bis (2,6-ditertiarybutylphenol), 4,4'-butylidene-bis (3-methyl-6-tertiarybutylphenol), 4,4'-
Thio-bis (3-methyl-6-tert-butylphenol), 4,4'-thiobis (2-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5) -Tert-butylphenyl) butane, pentaerythrityl-tetrakis [3-
(3,5-ditertiary-butyl-4-hydroxyphenyl) propionate] and the like.

The amount of the polymerization inhibitor (c) to be used is not particularly limited, but is usually based on the total weight of the epoxy resin (a-1) and the unsaturated monobasic acid (a-2). 0.0
The range of 1 to 5.0% by weight is preferably 0.05
The range of up to 3.0% is preferable from the viewpoint of excellent effect of preventing coloration of the cured product.

The reaction conditions and the like for producing the vinyl ester resin are not particularly limited, but as a concrete reaction method, for example, the following predetermined amount of epoxy resin (a-
1), unsaturated monobasic acid (a-2), a phenolic compound (b-1) as a reaction catalyst or an organic acid salt thereof (b-)
2) and the polymerization inhibitor (c) were charged into a reaction vessel, and 6
A method of carrying out the reaction at 0 to 150 ° C, preferably 80 to 120 ° C can be mentioned. The reaction time is not particularly limited,
Usually, it is preferable that the reaction is carried out for 3 to 20 hours, preferably 4 to 10 hours, and when the acid value reaches 3 to 15, the reaction is terminated by cooling.

The resin composition for artificial marble of the present invention comprises the vinyl ester resin obtained by the above-mentioned production method,
A compound having an ethylenically unsaturated double bond and an inorganic filler are essential components.

Here, typical examples of the monomer having an ethylenically unsaturated double bond include, for example, styrene, vinyltoluene, p-methylstyrene, α-methylstyrene, t-butylstyrene and halogenated styrene. , Aromatic vinyl compounds such as divinylbenzene; vinyl pivalate, vinyl 2-ethylhexanoate, vinyl laurate,
Carboxylic acid monovinyl esters such as vinyl benzoate; 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, phenyl (meth) Esters of (meth) acrylic acid such as acrylate, benzyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate; hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; methoxyethyl Alkoxyalkylene glycol mono (meth) acrylates such as (meth) acrylate and ethoxyethyl (meth) acrylate; N, N-dimethylamino Aminoalkyl (meth) acrylates such as tyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate; )
Acrylamide, N-methyl (meth) acrylamide,
(Meth) acrylamides such as N, N-dimethylacrylamide, N, N-dimethyl (meth) acrylamide, (meth) acryloylmorpholine; vinylpyrrolidone and the like. Among these, an aromatic vinyl compound is preferable because it has excellent boiling resistance when it is made into a cured product.

In the resin composition for artificial marble of the present invention, a non-polymerizable organic solvent may be used in combination with the above-mentioned monomer having an ethylenically unsaturated double bond. Specific examples include aromatic hydrocarbons such as toluene and xylene; alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; esters such as ethyl acetate and butyl acetate; ethers such as 1,4-dioxane and tetrahydrofuran. Kinds; Ketones such as methyl ethyl ketone and methyl isobutyl ketone;
Examples thereof include glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl acetate, and ethylene glycol monobutyl ether; alicyclic hydrocarbons such as cyclohexanone and cyclohexanol, and petroleum solvents such as petroleum ether and petroleum naphtha.

The monomer having an ethylenically unsaturated double bond and the non-polymerizable organic solvent are used as a diluent for the vinyl ester resin before curing, and the monomer having an ethylenically unsaturated double bond is used. The monomer is essential, and it is used alone or as a mixture of two or more kinds. The amount of them used is not particularly limited, but is the total amount as a diluent,
20 to 20 relative to 100 parts by weight of vinyl ester resin
The range is 0 parts by weight, preferably 30 to 150 parts by weight.

The inorganic filler, which is an essential component of the resin composition for artificial marble of the present invention, is not particularly limited, and examples thereof include aluminum hydroxide, aluminum oxide,
Examples thereof include calcium carbonate, glass powder, clay, talc, quartz powder, and crushed stone. Among them, aluminum hydroxide and glass powder are preferable from the viewpoint of excellent transparency.

The amount of the inorganic filler used is usually 30 in the composition.
~ 80% by weight.

The artificial marble composition of the present invention can be sufficiently cured by simply heating it without using a curing catalyst, but it goes without saying that an organic peroxide may be used. Further, by using a photopolymerization initiator, it is possible to cure with active energy rays such as ultraviolet rays and electron rays.

Typical organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide and cyclohexanone peroxide; diacyl peroxides such as benzoyl peroxide and isobutyl peroxide; cumene. Hydroperoxides such as hydroperoxide and t-butyl hydroperoxide; Dialkyl peroxides such as dicumyl peroxide and di-t-butyl peroxide; 1,1-di-t-butylperoxy-3,
3,5-trimethylcyclohexanone, 2,2-di-
Peroxyketals such as (t-butylperoxy) -butane; alkyl peresters such as t-butylperbenzoate and t-butylperoxy-2-ethylhexanoate; bis (4-t-butylcyclohexyl)
Examples thereof include peroxydicarbonate and percarbonates such as t-butylperoxyisobutylcarbonate. These organic peroxides can be heat-cured. These can be used alone or as a mixture of two or more kinds, and a curing system in which a metal salt such as cobalt naphthenate or cobalt octenoate is used in combination with a ketone peroxide such as methyl ethyl ketone peroxide or methyl isobutyl ketone peroxide; It is also possible to cure at room temperature by using a redox catalyst system such as a combination of aromatic tertiary amines such as N, N-dimethylaniline and acyl peroxides such as benzoyl peroxide.

The amount used is usually 0.1 to 5 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the vinyl ester resin and the monomer having an ethylenically unsaturated double bond. The ratio is 3 parts by weight.

Next, typical examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Benzoin and its alkyl ethers such as benzoin isobutyl ether and benzyl methyl ketal; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, diethoxyacetophenone, 2, 2
-Diethoxy-2-phenylacetophenone, 1,1-
Acetophenones such as dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one; methylanthraquinone, 2
Anthraquinones such as ethylanthraquinone, 2-tacharybutylanthraquinone, 1-chloroanthraquinone and 2-amylanthraquinone; thioxanthone,
Thioxanthones such as 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-methylthioxanthone and 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone , Benzophenones such as 4,4-bismethylaminobenzophenone and azo compounds. These can be used alone or as a mixture of two or more kinds, and further, tertiary amines such as triethanolamine and methyldiethanolamine; photo-initiated such as 2-dimethylaminoethylbenzoic acid and benzoic acid derivatives such as ethyl 4-dimethylaminobenzoate. It can be used in combination with auxiliary agents and the like.

The amount used is 10 based on the total weight of the vinyl ester resin and the monomer having an ethylenically unsaturated double bond.
0.5 to 20 parts by weight, preferably 1 to 0 parts by weight
The ratio is 15 parts by weight.

Further, in the resin composition for artificial marble of the present invention, if necessary, an inorganic thixotropic agent such as silica powder, an organic thixotropic agent such as hydrogenated castor oil, a coloring agent, a leveling agent, and a decoloring agent are used. A foaming agent, a release agent, a polymerization inhibitor, an inorganic fiber, an organic fiber and the like can be used in combination.

The method for preparing the resin composition for artificial marble of the present invention is not particularly limited. For example, the above-mentioned components may be used at room temperature or the composition using a kneader such as a kneader, mixer, roll mill or screw type extruder. Can be carried out in a temperature range where it does not cure.

The vinyl ester resin obtained by the production method of the present invention is not only used for artificial marble products but also for gel coat, hand layup, RTM molding, SMC,
It is also useful in applications such as BMC, cast molding, civil engineering adhesion, electrical insulation, composite materials, and UV curable paint.

[0038]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following, all parts and% are based on weight unless otherwise specified.

Example 1 "Epiclon 1050" (a bisphenol A type epoxy manufactured by Dainippon Ink and Chemicals, Inc.) was placed in a four-necked flask equipped with a stirrer, a condenser, a thermometer, a gas inlet tube, and a heating device. Resin, epoxy equivalent 470) 470 parts (1 equivalent) and methacrylic acid 86 parts (1 equivalent) were charged, and 0.28 of 2,6-di-tertiary-butyl-4-methylphenol was added to the total weight thereof. And 1.7 parts of 2,4,6-tris (dimethylaminomethyl) phenol were added, and the mixture was reacted at 110 ° C. for 5 hours. When the acid value reached 4, the reaction was terminated to obtain a vinyl ester resin. Obtained vinyl ester resin 6
0 part was dissolved with 40 parts of styrene monomer. Hereinafter, a mixture of these diluents is referred to as "vinyl ester resin A". Property values of the vinyl ester resin A are shown in Table 1.

Example 2 In the same manner as in Example 1, "Epiclone 1050" 470
And 86 parts of methacrylic acid were charged, and pentaerythrityl-tetrakis [3- (3,5-di-shartibutyl-4] was added.
-Hydroxyphenyl) propionate] 0.28
Part, 2,4,6-trisdimethylaminomethylpheno-
Of ethyl triethylhexoate was added to the mixture at 110 ° C.
When the acid value reached 4, the reaction was terminated to obtain a vinyl ester resin. 60 parts of the obtained vinyl ester resin was dissolved in 40 parts of styrene monomer. Hereafter, a mixture of this diluent and "vinyl ester resin B"
And The property values of the vinyl ester resin B are shown in Table 1.

Example 3 In the same manner as in Example 1, 380 parts (2 equivalents) of "Epiclon 850" (bisphenol A type epoxy resin manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent 190) and 172 parts of methacrylic acid were used. (2 equivalents) were charged, and 0.28 parts of 2,6-di-tert-butyl-4-methylphenol and 2,6- (dimethylaminomethyl) phenol 1.7 were added based on the total weight. Parts were added, and the mixture was reacted at 110 ° C. for 6 hours, and when the acid value reached 4, the reaction was terminated to obtain a vinyl ester resin. 60 parts of the obtained vinyl ester resin was dissolved in 40 parts of styrene monomer. Hereinafter, a mixture of these diluents will be referred to as "vinyl ester resin C". Property values of the vinyl ester resin C are shown in Table 1.

Example 4 In the same manner as in Example 1, 360 parts (2 equivalents) of "Epiclone N-738" (phenol novolac type epoxy resin manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent 180) and methacrylic acid 172 were used. Parts (2 equivalents) were charged, and 2,6-ditertiarybutyl-4-based on the total weight thereof.
0.28 parts of methylphenol and 1.6 parts of 2,4,6-tris (dimethylaminomethyl) phenol were added,
The reaction was carried out at 100 ° C. for 8 hours, and when the acid value reached 4, the reaction was terminated to obtain a vinyl ester resin. 60 parts of the obtained vinyl ester resin was dissolved in 40 parts of styrene monomer. Hereinafter, a mixture of this diluent is referred to as "vinyl ester resin D". The first property value of vinyl ester resin D
Shown in the table.

Comparative Example 1 In the same manner as in Example 1, "Epiclone 1050" 470
Parts and 86 parts of methacrylic acid were charged, 0.28 parts of hydroquinone and 1.7 parts of 2-methylimidazole were added,
The reaction was carried out at 110 ° C. for 5 hours, and when the acid value reached 4, the reaction was terminated to obtain a vinyl ester resin. 60 parts of the obtained vinyl ester resin was dissolved in 40 parts of styrene monomer. Hereinafter, a mixture of this diluent is referred to as "vinyl ester resin E". Property values of the vinyl ester resin E are shown in Table 1.

Comparative Example 2 In the same manner as in Example 1, "Epiclone 1050" 470
And 86 parts of methacrylic acid were charged, 0.28 part of monomethyl ether hydroquinone, 1.7 parts of triphenylphosphine and 0.11 part of phosphorous acid were added, and the mixture was reacted at 110 ° C for 5 hours to reach an acid value of 4. Then, the reaction was terminated to obtain a vinyl ester resin. Obtained vinyl ester resin 6
0 part was dissolved with 40 parts of styrene monomer. Hereinafter, a mixture of this diluent is referred to as "vinyl ester resin F". Property values of the vinyl ester resin F are shown in Table 1.

Comparative Example 3 In the same manner as in Example 1, "Epiclone N-738" 36
0 parts and 172 parts of methacrylic acid were charged, 0.27 parts of hydroquinone and 1.7 parts of 2-methylimidazole were added and reacted at 100 ° C for 7 hours, and when the acid value reached 4, the reaction was terminated and vinyl ester A resin was obtained. 60 parts of the obtained vinyl ester resin was dissolved in 40 parts of styrene monomer. Hereinafter, the mixture of these diluents is referred to as "vinyl ester resin G". Property values of the vinyl ester resin G are shown in Table 1.

[0046]

[Table 1] ¹⁾ : Acetylacetone peroxide 1.0phr, 6% Co-nap
h. 0.2phr 25 ℃ measurement ²⁾ : Percadox 16 1.0phr, 80 ℃ measurement

Examples 5 to 8 and Comparative Examples 4 to 6 Resin compositions for artificial marble according to the formulations shown in Table 2 using the vinyl ester resins A to G obtained in Examples 1 to 4 and Comparative Examples 1 to 3. I got a thing. Next, after curing each composition, the boiling resistance and heat resistance test of the cured product were performed.
The results are shown in Table 2.

The method of preparing the specimen used for the boiling resistance and heat resistance tests, the test method of each performance and the judgment criteria are as follows. Preparation method of test sample: According to the formulation shown in Table 2, vinyl ester resin, "Percadox 16" (bis (4-t-butylcyclohexyl) peroxydicarbonate manufactured by Kayaku Akzo Co., Ltd.), Alternatively, glass powder was added and mixed well. After defoaming under reduced pressure, the product was poured into a 3 mm thick mold made of a glass plate, pre-cured at 60 ° C., and after-cured at 110 ° C. for 1 hour to prepare a 3 mm thick casting plate. Using the cast plate obtained, heat resistance test and boiling test,
The degree of discoloration was measured.

Heat resistance test: A casting plate of 5 cm square and 3 mm thick was left in a hot air dryer kept at 180 ° C. for 1 hour and then taken out, and the color difference of the casting plate was measured. The visual inspection and the color difference value were carried out.

Boil test: 5 cm square, 3 mm thick casting plate was immersed in hot water maintained at 95 to 98 ° C. for 5
After 00 hours, it was taken out, and the appearance of the casting plate was visually inspected and the color difference was measured.

Appearance: Visual evaluation, evaluation criteria are as follows. ○: No change at all Δ: Discoloration and whitening are observed.

X: Blisters and cracks are also seen. Color difference ... Double-Beam Co made by Tokyo Denshoku Co., Ltd.
The measurement was performed using a lor Analyzar C-5200. The evaluation is indicated by the value of ΔE.

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

EFFECTS OF THE INVENTION According to the present invention, the liquid resin is lighter in color and has better curability than conventional ones, and swelling or cracking is not generated even when the cured product is exposed to hot water or high temperature for a long time. It is possible to provide a vinyl ester resin with less color change and less discoloration. Further, it is possible to provide a resin composition for artificial marble which is excellent in hot water resistance and heat resistance and has an excellent appearance.

Claims (6)

[Claims] 1. A phenolic compound (b-1) having an epoxy compound (a-1) and an unsaturated monobasic acid (a-2) and having an aliphatic tertiary amino group in an aromatic nucleus, or the phenolic compound. The method for producing a vinyl ester resin, which comprises reacting in the presence of the organic acid salt (b-2) and the polymerization inhibitor (c). 2. The method according to claim 1, wherein the phenolic compound (b-1) is represented by the following general formula (1). [Chemical 1] (X, Y and Z are hydrogen atoms or those represented by the following general formula (2). However, in the general formula (2), R ₁ and R ₂
Is an alkyl group, n is an integer of 1 to 10, and
At least one of X, Y and Z is represented by the general formula (2). ) [Chemical 2] 3. The method according to claim 1 or 2, wherein the polymerization inhibitor (C) is hindered phenol. 4. A phenolic compound (b-1) having an epoxy group (a-1) and an unsaturated monobasic acid (a-2) having an aliphatic tertiary amino group in an aromatic nucleus, or the phenolic compound. A vinyl ester resin obtained by reaction in the presence of the organic acid salt (b-2) and a polymerization inhibitor (c), a compound having an ethylenically unsaturated double bond, and an inorganic filler are essential components. A resin composition for artificial marble, characterized by being: 5. The composition according to claim 4, wherein the phenolic compound (b-1) is represented by the following general formula (1). [Chemical 3] (X, Y and Z are hydrogen atoms or those represented by the following general formula (2). However, in the general formula (2), R ₁ and R ₂
Is an alkyl group, n is an integer of 1 to 10, and
At least one of X, Y and Z is represented by the general formula (2). ) [Chemical 4] 6. The composition according to claim 4, wherein the polymerization inhibitor (C) is hindered phenol.