JP4592610B2 - Molding material - Google Patents

Description

The present invention relates to a molding material. More specifically, the present invention relates to a molding material that can be suitably used as a material for artificial marble used in decorative materials for buildings, residential equipment, various decorative items, and the like.

Since artificial marble has an appearance that is often mistaken for natural marble, it can be used as high-end residential building materials such as tiles and wall panels, such as architectural decorative materials; bathtubs (tubs), vanity tables (vanity counters), Widely used for sinks, bathroom panels, system kitchen tops (kitchen counters), table tops, toilet counters and other household equipment; Such artificial marble is made from a material in which various inorganic substances are filled in a resin. As the resin, unsaturated polyester resin, acrylic resin, or the like has been mainly used.

Vinyl ester resin is a resin that exhibits excellent chemical resistance, water resistance, heat resistance, mechanical properties, etc. when cured, but because it is a highly colored resin, it is suitable for artificial marble applications where transparency is required. It was not used much. However, in recent years, with the development of light-colored vinyl ester resins, vinyl ester resins have also been applied to artificial marble. When vinyl ester resin is used, when it is molded by heat curing, an artificial marble having transparency and little coloration can be obtained, but when molding at room temperature or a temperature close to room temperature, Since it is necessary to add a large amount of a redox-active organic cobalt compound that greatly colors the cured product as a curing accelerator for curing, an artificial marble having sufficient transparency could not be obtained. For this reason, when molding materials containing vinyl ester resins are used for artificial marble applications, a method of molding by heat curing that does not require the use of redox-active organic cobalt compounds that cause coloring has been used. In order to reduce costs and improve workability, there is a demand for the development of a molding material that can harden a resin at a temperature close to room temperature and obtain artificial marble having sufficient transparency.

As a molding material for artificial marble using a conventional vinyl ester resin, a vinyl ester resin composition for artificial marble containing a vinyl ester and a polymerizable monomer, triarylantimony, hindered phenol is disclosed (for example, (See Patent Document 1). However, this composition is cured by heating, and there is room for improvement as a molding material for artificial marble that cures at room temperature.

Moreover, the resin composition for artificial marble which uses the vinyl ester resin obtained from an epoxy resin and unsaturated monobasic acid, the compound which has an ethylenically unsaturated double bond, and an inorganic filler as an essential component (for example, refer patent document 2). ), 2,5-bis [2- (benzoxazolyl)] into a vinyl ester resin composition obtained by dissolving a vinyl ester resin obtained from an epoxy resin and an unsaturated monobasic acid in a polymerizable monomer A vinyl ester resin composition containing a thiophene compound (for example, see Patent Document 3), a vinyl ester resin obtained from an epoxy resin and an unsaturated monobasic acid, a styrene monomer, and a large amount of acrylic acid or methacrylic acid. A vinyl ester resin composition containing a functional ester derivative is disclosed (for example, see Patent Document 4). These vinyl ester resin compositions can be cured at room temperature by using not only curing by heating but also a photopolymerization initiator, ketone peroxide, etc., but the resulting cured product is transparent. Since the properties are not sufficient, there is room for improvement as a molding material that can be cured at room temperature and obtain an artificial marble having sufficient transparency.

Furthermore, a vinyl ester resin composition comprising a vinyl ester resin and aluminum hydroxide surface-treated with an acrylic silane coupling agent or an acylate titanium coupling agent is disclosed (for example, see Patent Document 5). Although this vinyl ester resin composition is described as being cured at room temperature and giving artificial marble with excellent transparency, a cured product obtained from this vinyl ester resin composition is sufficient. Since it does not have light transmittance, there has been room for improvement as a molding material that has sufficient light transmittance and can be suitably used for artificial marble applications requiring transparency.
JP 2004-35703 A (page 1-2) JP-A-7-109332 (page 1-2, page 5) Japanese Patent Laid-Open No. 9-104728 (page 1-2, page 5) JP-A-10-251499 (page 1-2, page 5) JP-A-2-99509 (page 1-2, page 4)

The present invention has been made in view of the above situation, and can be molded at room temperature without reducing the properties of a thermosetting resin containing vinyl ester as a main component, thereby forming an artificial marble with little coloration. The purpose is to provide materials.

The inventors of the present invention have made various investigations on molding materials that can be cured at room temperature without degrading the properties of thermosetting resins mainly composed of vinyl esters to obtain artificial marble with little coloration. In a molding material comprising a thermosetting resin having a main component and an inorganic filler having a specific refractive index, among various curing accelerators, a curing accelerator having a high effect of curing a vinyl ester resin at room temperature. There is a combination of redox-active organic cobalt compounds that cause coloration in combination with an organic potassium compound, and each of these is used by adjusting the concentration so that it is contained in a specific ratio in the molding material. It can be seen that coloring of the molding material can be suppressed without impairing the curing promoting action of the redox active organic cobalt compound. It was. This gives a molding material that can be suitably used for artificial marble applications because it cures at room temperature without degrading the properties of thermosetting resins mainly composed of vinyl esters, and gives a cured product with less coloration. As a result, the present inventors have arrived at the present invention.

That is, the present invention is a molding material comprising a thermosetting resin, a redox-active organic cobalt compound, an organic potassium compound, and an inorganic filler, and the molding material is based on 100 parts by mass of the thermosetting resin. The redox-active organic cobalt compound is 0.0003 to 0.01 parts by mass as metallic cobalt, the organic potassium compound is 0.001 to 0.1 parts by mass as metallic potassium, and the refractive index is 1.50 to 1.60. 50 to 400 parts by mass of an inorganic filler, and the thermosetting resin is composed of a radical polymerizable oligomer and a radical polymerizable monomer, and 65% or more of the radical polymerizable oligomer is vinyl. A molding material that is an ester.
The present invention is described in detail below.

The molding material of the present invention is a molding material that can be cured at room temperature to obtain an artificial marble with little coloring without deteriorating the properties of a thermosetting resin containing vinyl ester as a main component. Since the vinyl ester resin has superior characteristics in boiling resistance, heat resistance, etc., compared with the unsaturated polyester resin, the molding material of the present invention is more in comparison with the material having the unsaturated polyester resin as the main component of the resin. Thus, it provides a cured product having excellent characteristics, and can be suitably used for artificial marble.
The thermosetting resin mainly composed of the vinyl ester contained in the molding material of the present invention, the redox-active organic cobalt compound, the organic potassium compound, and the inorganic filler may each be one kind, or two or more kinds. Also good. Moreover, as long as it contains at least one of each of these components, it may contain other components.

The molding material of the present invention contains 0.0003 to 0.01 parts by mass of redox-active organic cobalt compound as metallic cobalt with respect to 100 parts by mass of thermosetting resin mainly composed of vinyl ester. It is preferable to contain -0.009 mass part. More preferably, it contains 0.0005 to 0.008 parts by mass.
In addition, it contains 0.001 to 0.1 parts by mass with respect to 100 parts by mass of a thermosetting resin having vinyl ester as a main component, using an organic potassium compound as metal potassium, but 0.002 to 0.09 parts by mass is included. It is preferable that it is 0.003 to 0.08 parts by mass.
When the content of the redox-active organic cobalt compound and the organic potassium compound is in such a range, the molding material should give a cured product with less coloring without impairing the high curing acceleration effect of the redox-active organic cobalt compound. Is possible.
In the present invention, there is a technical significance in using the redox-active organic cobalt compound and the organic potassium compound in combination, and the technical significance of the above numerical range is described in Examples and Comparative Examples described later. This is supported by experimental data.

The vinyl ester contained in the molding material of the present invention is a vinyl ester (radically polymerizable oligomer) obtained by adding an unsaturated monobasic acid to an epoxy compound as described in detail below.
In the reaction of adding an unsaturated monobasic acid to an epoxy compound, the epoxy compound and the unsaturated compound are unsaturated at a ratio such that the equivalent of the carboxyl group of the unsaturated monobasic acid to the epoxy group of the epoxy compound is 0.8 to 1.2. It is preferable to use a monobasic acid. More preferably, the epoxy compound and the unsaturated monobasic acid are used in such a ratio that the equivalent of the carboxyl group of the unsaturated monobasic acid to the epoxy group of the epoxy compound is 0.9 to 1.1.
Moreover, as reaction temperature of reaction which adds an unsaturated monobasic acid to the said epoxy compound, it is preferable to set it as 80-150 degreeC. More preferably, it is 100-130 degreeC.

Examples of the epoxy compound used for the vinyl ester include a bisphenol type epoxy compound, a novolac type epoxy compound, an aliphatic type, an alicyclic type, a monocyclic epoxy compound, and an amine type epoxy compound. Examples of bisphenol type epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol AD type epoxy compounds, bisphenol S type epoxy compounds, brominated bisphenol A type epoxy compounds, and the like. Examples thereof include phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, brominated novolac type epoxy compounds and the like. Examples of the aliphatic epoxy compound include a hydrogenated bisphenol A type epoxy compound and a propylene glycol polyglycidyl ether compound. Examples of the alicyclic epoxy compound include alicyclic diepoxy acetal, dicyclopentadiene dioxide, vinyl hexene. Dioxide, vinyl hexene dioxide, glycidyl methacrylate and the like can be mentioned.
These epoxy compounds may be used alone or in combination of two or more. In addition, these epoxy compounds may be used as an epoxy compound modified with a dibasic acid such as a phenolic compound such as bisphenol A, adipic acid, sebacic acid, dimer acid, or liquid nitrile rubber.

As unsaturated monobasic acid used for vinyl ester, it has monocarboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid and sorbic acid, and dibasic acid anhydride and at least one unsaturated group in the molecule. Examples include a reaction product with alcohol. Examples of the dibasic acid anhydride include aliphatic or aromatic dicarboxylic acids such as maleic anhydride, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Examples of the alcohol having an unsaturated group include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, pentaerythritol tri (meth) acrylate, glycerin di (meth) acrylate and the like. .

The epoxy compound used for the vinyl ester is not particularly limited as long as it contains a compound having at least two epoxy groups in the molecule, but it is a bisphenol type excellent in mechanical strength, corrosion resistance, and heat resistance. Epoxy compounds are preferred.
Moreover, as an unsaturated monobasic acid used for a vinyl ester, a C6 or less thing is preferable among the things mentioned above from a heat resistant and chemical-resistant viewpoint. More preferred are acrylic acid and methacrylic acid.

In the thermosetting resin having the vinyl ester as a main component, the content of the radical polymerizable monomer is preferably 20 to 60%. When the content of the radical polymerizable monomer is 20 to 60%, the resulting thermosetting resin mainly composed of vinyl ester has a viscosity suitable for artificial marble. More preferably, it is 30 to 50%.

Examples of the radical polymerizable monomer used in the thermosetting resin containing the vinyl ester as a main component include various vinyl monomers such as a styrene monomer, vinyl toluene, and (meth) acrylic acid esters. As (meth) acrylic acid esters, methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2- (meth) acrylic acid ester having one acryloyl group in the molecule, Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, glycidyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, etc. Is mentioned.

Examples of (meth) acrylic acid ester having two acryloyl groups in the molecule include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. , Neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and the like.
Examples of the (meth) acrylic acid ester having three or more acryloyl groups in the molecule include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like.

In the thermosetting resin mainly composed of the vinyl ester, 65% (mass%) or more of the radical polymerizable oligomer is vinyl ester, but contains less than 35% of the radical polymerizable oligomer other than the vinyl ester. May be. As the oligomer other than the vinyl ester, an unsaturated polyester is preferable. When a vinyl ester and an unsaturated polyester are used in combination, the blending ratio of the vinyl ester and the unsaturated polyester is less than 35%, more preferably less than 30%. When 65% or more is vinyl ester, the performance of vinyl ester can be brought out so that the physical properties required for the molding material can be satisfied at a high level in terms of boiling discoloration and heat discoloration.
In the present invention, in order to exhibit in the molding material the physical properties of the vinyl ester that are excellent in heat discoloration, the proportion of the vinyl ester in the radical polymerizable oligomer, as can be seen from the experimental data of Examples and Comparative Examples described later. Is set to 65% or more.

The unsaturated polyester can be obtained by a condensation reaction of an acid component (polybasic acid component) with a glycol component and / or an epoxy compound component. The reaction molar ratio of the acid component to the glycol component and / or the epoxy compound component is not particularly limited. For example, when the acid component: glycol component and / or epoxy compound component is used, 10: 8 to 10: 12 is preferred.

The polybasic acid component may be a compound having two or more substituents capable of reacting with a hydroxyl group and / or an epoxy group contained in a glycol component and / or an epoxy compound component to form an ester bond, An unsaturated polybasic acid is essential, and a part thereof may be replaced with a saturated polybasic acid.
Examples of the unsaturated polybasic acid include α, β-unsaturated polybasic acids such as maleic acid, fumaric acid, aconitic acid, and itaconic acid; β, γ-unsaturated polybasic acids such as dihydromuconic acid; One or more of acid anhydrides; halides of these acids; alkyl esters of these acids, and the like can be used.

Examples of the saturated polybasic acid include aliphatic saturated polybasic acids such as malonic acid, succinic acid, and adipic acid; aromatic saturated polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid Acids; cycloaliphatic saturated polybasic acids such as het acid and dimer acid; anhydrides of these acids; halides of these acids; use of one or more of these acids such as alkyl esters it can.

Examples of the glycol component include ethylene glycol, diethylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, propylene glycol, and dipropylene. One of glycol, neopentyl glycol, triethylene glycol, hydrogenated bisphenol A, alkylene oxide adduct of bisphenol A, alkylene oxide adduct of hydrogenated bisphenol A, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, etc. Two or more types can be used.

Among the above-mentioned epoxy compound components, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, 3,4-epoxy-1-butene, glycidyl acrylate, glycidyl methacrylate, bisphenol A diglycidyl ether, etc. 1 type (s) or 2 or more types can be used.

As the redox-active organic cobalt compound, one or more of cobalt salts of organic acids and organic cobalt complexes can be used.
Examples of cobalt salts of organic acids include cobalt naphthenate and cobalt octenoate. Moreover, cobalt acetylacetonate etc. are mentioned as an organic cobalt complex.
Among these, it is preferable to use cobalt naphthenate or cobalt octenoate.

Examples of the organic potassium compound include potassium octenoate and potassium naphthenate. Among these, it is preferable to use potassium octenoate from the viewpoint of availability. When potassium octenoate is used, it can be set as the molding material which gives the hardened | cured material with less coloring, without impairing the hardening acceleration effect of a redox active organic cobalt compound.

Further, as the curing accelerator, in addition to the above-described organic cobalt and organic potassium, other curing accelerators exhibiting a curing acceleration effect can be used, and further, an acceleration assistant can be used. When using another hardening accelerator, it is preferable that it is 0-5 mass parts with respect to 100 mass parts of thermosetting resins which have the vinyl ester of this invention as a main component.

Examples of the other curing accelerator include manganese naphthenate, zinc naphthenate, calcium naphthenate, magnesium naphthenate, manganese octenoate, zinc octenoate, calcium octenoate, zirconium octenoate and the like. Examples of the promoter aid include β- such as acetylacetone, methyl acetoacetate, ethyl acetoacetate, α-acetyl-γ-butyrolactone, N-pyrodininoacetoacetamide, N, N-dimethylacetoacetamide and the like. Diketones; quaternary ammonium salts such as triethylbenzylammonium chloride; amines such as dimethylaniline, N, N-dimethyltoluidine, N, N-diethylaniline, N, N-di (hydroxy) -4-methylaniline, etc. 1 type (s) or 2 or more types, such as (beta) -ketoester and (beta) -ketoamide, can be used.

The inorganic filler contained in the molding material of the present invention is not particularly limited as long as it has a refractive index of 1.50 to 1.60. Aluminum hydroxide (ATH), calcium sulfate, alumina, glass microballoon, clay, talc, glass 1 type, or 2 or more types, such as powder and mica, can be used. Among these, it is preferable to use aluminum hydroxide or glass powder.
In addition, the numerical range of refractive index 1.50-1.60 is a preferable range of the refractive index of an inorganic filler when it is used as artificial marble. By using such an inorganic filler, artificial marble It can be made transparent and have a high-class feeling. That is, by setting the refractive index in the range of 1.50 to 1.60, the refractive index of the inorganic filler becomes equivalent to the refractive index of the cured thermosetting resin, and the molding material is made transparent. .

The molding material of the present invention also includes an air drying property imparting agent, a thixotropic agent, a fiber reinforcing material (reinforcing fiber material), a polymerization inhibitor, an antifoaming agent, a thickener, within a range not impairing the effects of the present invention. Low shrinkage agent, internal mold release agent, colorant, patterning agent, chain transfer agent, inert powder, UV absorber, fluorescent whitening agent, bluing agent, anti-aging agent, plasticizer, flame retardant, stabilizer Etc. can be included.

The air drying property-imparting agent is deposited on the surface of a film or molded product formed from the molding material when the molding material containing the resin is cured, and forms an air blocking layer on the surface. It has an action of preventing oxygen in the resin from inhibiting radical polymerization of the resin and improving the drying property of the resin. Examples of such air drying property imparting agents include natural waxes and synthetic waxes. These may be used alone or in combination of two or more.

As the air drying property imparting agent, paraffin wax is preferably used among the natural wax and synthetic wax.
In addition, when hardening a molding material at normal temperature, it is preferable to use what has melting | fusing point 40-40 degreeC classified into JISK2235-1991 as said air-drying property imparting agent. Thereby, in the construction of the molding material, it becomes easy to deposit on the surface of the coating film or molded product formed from the molding material being cured, so that a barrier layer against air is sufficiently formed.
When it is necessary to use the air drying property-imparting agent, the amount used is not particularly limited, but 0.001 part by mass (10 ppm) or more with respect to 100 parts by mass of the thermosetting resin mainly composed of vinyl ester, The amount is preferably 1 part by mass or less. More preferably, they are 0.01 mass part or more and 0.3 mass part or less.

Examples of the thixotropic agent include fumed silica, and the amount used is not particularly limited, but is 0.1 parts by mass or more with respect to 100 parts by mass of the thermosetting resin containing vinyl ester as a main component. It is preferably 5 parts by mass or less.
Examples of the fiber reinforcement include inorganic fibers such as glass fibers, carbon fibers, metal fibers, and ceramic fibers; organic fibers such as aramid, polyester, vinylon, phenol, and Teflon (registered trademark); natural fibers, and the like. The amount used is not particularly limited, but is preferably 5 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the thermosetting resin mainly composed of vinyl ester.

The polymerization inhibitor is used to adjust the pot life and the rise of the curing reaction. For example, hydroquinones, benzoquinones, catechols, phenols; phenothiazine, copper naphthenate, N-oxyls, etc. Can do.
As the antifoaming agent, in addition to silicon-based ones, commercially available polymer-based anti-sagging agents and other additives can be used.
As the thickener, polyvalent metal oxides such as magnesium oxide, calcium oxide and zinc oxide; polyvalent metal hydroxides such as magnesium hydroxide and calcium hydroxide; polyfunctional isocyanates and the like are suitable.

The low shrinkage agent can be used to adjust molding shrinkage, such as polystyrene, polyethylene, polyvinyl acetate, cross-linked polystyrene, polyvinyl acetate-polystyrene block copolymer, multiphase structure polymer such as acrylic / styrene, Examples include cross-linked / non-cross-linked multi-phase polymer, SBS (rubber), etc. The amount used is not particularly limited, but 1 part by mass with respect to 100 parts by mass of thermosetting resin mainly composed of vinyl ester As mentioned above, it is preferable that it is 20 mass parts or less.
Examples of the internal mold release agent include silicon internal mold release agents such as dimethylpolysiloxane having a dimethylsiloxane structure, and the amount of the internal mold release agent is 0 with respect to 100 parts by mass of the thermosetting resin mainly composed of vinyl ester. It is preferable that the amount be 0.01 parts by mass or less.
Examples of the patterning agent include aluminum oxide, PET film, mica, ceramic and those coated with a colorant, a surface treatment agent, etc., a plating treatment, a thermosetting resin, an inorganic filler, a colorant, and the like. Examples include those that are heat-cured and pulverized.

Examples of the chain transfer agent include mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid, α-methylstyrene dimer (4-methyl-2-4-diphenylpentene), α-methylstyrene, and the like. 1 type (s) or 2 or more types can be used.
As the use ratio of the chain transfer agent, it is preferable that the lower limit is 0.01 parts by mass and the upper limit is 10 parts by mass with respect to 100 parts by mass of the thermosetting resin mainly composed of vinyl ester.
In addition, fluorescent whitening agents, bluing agents, and the like can be used for the purpose of alleviating the yellowishness of the cured product.

When the molding material of the present invention is used for artificial marble, a cured product used as the artificial marble is obtained by adding a curing agent to the molding material and curing it.
As the curing agent, those commonly used can be used, for example, acetylacetone peroxide, methyl ethyl ketone peroxide (MEKPO), diethyl ketone peroxide, methyl propyl ketone peroxide, methyl isobutyl ketone peroxide, methyl acetoacetate. Peroxide, ethyl acetoacetate peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, cumene peroxide, benzoyl peroxide, t-butylisopropyl peroxycarbonate, 1,1-dibutyl Peroxy-3,3,5-trimethylcyclohexanone, t-butylperoxy-2-ethylhexanoate, amino Use one or more of peroxy-p-2-ethylhexanoate, 2-ethylhexyl peroxy-2-ethylhexanoate, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, etc. Can do. Although it does not specifically limit as usage-amount, It is suitable that it is 0.5 mass part or more and 5 mass parts or less with respect to 100 mass parts of thermosetting resins which have vinyl ester as a main component.

Although the molding material of this invention can be hardened at normal temperature, it is preferable that it is 0-40 degreeC as hardening temperature. More preferably, it is 10-35 degreeC. The curing time is preferably shorter in consideration of productivity. After curing at normal temperature, curing can be completed in a short time by heating to about 50 to 70 ° C. The post-curing time is preferably within 5 hours, more preferably within 3 hours.

The molding material of the present invention is a cured product having the above-described structure, cured at room temperature without impairing the excellent properties of the thermosetting resin mainly composed of vinyl ester, and having sufficient transparency with little coloring. Therefore, it is a molding material that can be suitably used as a material for artificial marble.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

<Making artificial marble>
Resins excluding aluminum hydroxide and Parmec N (manufactured by NOF Corporation) as a curing agent in the compounds obtained by sequentially stirring and mixing in accordance with the formulation shown in Examples 1 to 16 and Comparative Examples 1 to 12 1 part by mass was added to 100 parts by mass of the minute, and mixed by stirring. The compound containing the curing agent was cast into a glass plate sandwiched with spacers so that the thickness of the molded product was 8 mmt.
After standing at room temperature (about 25 ° C) for 2 hours, the glass plate and the spacer are removed, and the resulting molded product is cured for 1 hour in a hot air dryer maintained at 60 ° C to obtain an artificial marble molded product for physical property evaluation. It was. Evaluation of the obtained artificial marble molded article for evaluating physical properties was performed by measuring boiling discoloration, heat discoloration, light transmittance, and surface hardness during demolding. In addition, an artificial marble molded product for initial color evaluation was separately prepared, and initial color evaluation was performed. The results are shown in Tables 1-3. The evaluation method for each evaluation item is shown below.

<Preparation of molded product for initial color evaluation (artificial marble before physical property evaluation)>
A molded product for color evaluation which does not use an accelerator which is a coloring base was prepared by heat curing as follows.
To 100 parts of vinyl ester resin, 200 parts of aluminum hydroxide and 2 parts of Percure-HO (manufactured by NOF Corporation) were stirred and mixed, and cured in a hot air dryer maintained at 100 ° C. for 1 hour. An artificial marble molded product for color evaluation was obtained.
[Initial color]
A color difference ΔL was measured by comparing an artificial marble molded article for evaluating physical properties with an initial molded article for evaluating color. Color difference ΔL was measured using SZ-Σ-90 manufactured by Nippon Denshoku Industries Co., Ltd.
Color difference ΔL = (L value of artificial marble molded product for color evaluation) − (L value of artificial marble molded product for physical property evaluation)
The larger the absolute value of ΔL, the greater the coloring.
[Light transmittance]
The light transmittance of an artificial marble molded article for physical property evaluation cut to 50 mm × 50 mm × 8 mm was measured with a turbidimeter 300A manufactured by Nippon Denshoku Industries Co., Ltd.
[Boil discoloration]
A product obtained by cutting an artificial marble molded article for physical property evaluation into 50 mm × 50 mm × 8 mm was fully immersed in hot water maintained at 95 to 98 ° C., taken out after 1000 hours, and the color difference ΔE before and after immersion was measured.
Color difference ΔE was measured using SZ-Σ-90 manufactured by Nippon Denshoku Industries Co., Ltd.

[Heat-resistant discoloration]
An artificial marble molded article for physical property evaluation cut into 50 mm × 50 mm × 8 mm was left in a hot air dryer maintained at 100 ° C. for 5 hours, and the color difference ΔE before and after hot air drying was measured.
Color difference ΔE was measured using SZ-Σ-90 manufactured by Nippon Denshoku Industries Co., Ltd.
[Surface hardness during demolding]
When producing the artificial marble for evaluating physical properties, the surface hardness immediately after removing the glass plate and the spacer was measured.
The surface hardness was measured using a Barcol hardness tester GZJ934-1.
The surface hardness at the time of demolding is an index for confirming the degree of cure of the molded product. When the hardness is low, it becomes difficult to remove the mold, and the physical properties inherent in the resin do not appear.
When molding artificial marble with room temperature curing, the FRP mold is used. However, when heat is applied, the mold is damaged, so that the mold is removed before post-curing.

In Examples and Comparative Examples, the following materials were used for the production of molding materials.
Vinyl ester resin; Polyhope RF-711BN manufactured by Japan Composites (radical polymerizable oligomer / radical polymerizable monomer = 65/35)
Unsaturated polyester resin; Polyhop 6339 manufactured by Japan Composites (radical polymerizable oligomer / radical polymerizable monomer = 60/40)
Cobalt octenoate 8%; metallic cobalt 8% contained Toei Kakko Co., Ltd. Naphthenic acid cobalt 6%; metallic cobalt 6% contained Toei Kakko Co., Ltd. potassium octenoate 13%; metallic potassium 13% contained Containing 5% metallic calcium Aluminum hydroxide manufactured by Toei Chemical Co., Ltd .; Hydylite H-341 (refractive index 1.57) TEBAC manufactured by Showa Denko KK; triethylbenzylammonium chloride

As shown in Comparative Example 1, when the content of the redox active organic cobalt compound was small, the curing was slow and the hardness at the time of demolding was low. In addition, as shown in Comparative Examples 4, 5, and 10, when the amount of the organic potassium compound is small or absent, the hardness at the time of demolding is similarly lowered.
As shown in Comparative Examples 2 and 6, when the content of the redox-active organic cobalt compound was large, coloring was increased and the light transmittance was also decreased.
As shown in Comparative Example 3, when the amount of the organic potassium compound was large, cracks occurred in the cured product.
As shown in Comparative Examples 7, 8, and 9, when another accelerator was used instead of the organic potassium compound, curing was slow and it was impossible to remove the mold.
As shown in Comparative Examples 11 and 12, when a large amount of unsaturated polyester was blended, boiling discoloration and heat discoloration increased.

Claims (2)

A molding material comprising a thermosetting resin, a redox-active organic cobalt compound, an organic potassium compound, and an inorganic filler,
The molding material is based on 100 parts by mass of the thermosetting resin.
0.0003-0.01 parts by mass of redox active organic cobalt compound as metallic cobalt,
0.001 to 0.1 parts by mass of an organic potassium compound as metal potassium,
Comprising 50 to 400 parts by weight of an inorganic filler having a refractive index of 1.50 to 1.60,
The thermosetting resin comprises a radical polymerizable oligomer and a radical polymerizable monomer, and a molding material characterized in that 65% by mass or more of the radical polymerizable oligomer is a vinyl ester. An artificial marble obtained by curing the molding material according to claim 1.