KR19990086211A - Resin composition, artificial marble obtained by molding of this composition and method for producing same - Google Patents

Abstract

The present invention provides a resin composition comprising the following components:

10 to 40% by weight of (a) an unsaturated monomer having at least two double bonds capable of causing radical polymerization or (ii) a mixture of said unsaturated monomer and an unsaturated monomer copolymerizable with said unsaturated monomer,

(b) 50 to 85 weight percent of an inorganic filler,

(c) 1 to 20% by weight of the crosslinked resin particles,

(d) 0.1 to 20% by weight resin with methyl methacrylate units, and

(e) 0.01 to 5% by weight radical polymerization initiator.

The resin composition is excellent in handleability, does not generate odor and can be easily molded to obtain artificial marble.

Description

Resin composition, artificial marble obtained by molding of this composition and method for producing same

The present invention relates to a resin composition suitable for producing artificial marble having excellent moldability and heat resistance, and to artificial marble obtained by molding the resin composition.

In the method using a sheet molding compound (SMC) material or a bulk molding compound (BMC) material containing an unsaturated polyester resin as a main component, respectively, using the conventional hand lay-up molding method and spray-up molding method, respectively. The reason for this is because the molding operation of this method is simple, and these materials such as SMC and BMC are used for the bath and the like.

However, these materials containing an unsaturated polyester resin as a main component have a problem that they are weak in hot water resistance and durability because they are not hydrolyzed under alkaline conditions.

In order to solve these problems, various methods have been proposed.

For example, JP-B 5-13899 discloses (i) 100 parts by weight of a "monomer A" substrate containing at least 20% by weight of multifunctional (meth) acrylate, (ii) 20 mesh 50 to 300 parts by weight of a "methacryl based resin powder B" derived from a monomer having a grit of less than or equal to 50,000 and an average molecular weight of 50,000 to 200,000 and containing methacrylate as an essential component, (iii) for monomer A 0.5 to 2 parts by weight of curing agent C ", (iv) 100 to 500 parts by weight of" inorganic filler D ", and optionally, (v) mixing, kneading, heating the binder, colorant and reinforcing agent at room temperature or below the curing temperature And aging to obtain a molding material in clay form or solid form at room temperature, and to prepare a natural grain-like product in which the obtained molding material is molded and cured under pressure while heating.

Japanese Laid-Open Patent Publication (JP-A) 5-32720 discloses (i) 20 to 60% by weight of an unsaturated monomer containing methyl methacrylate as the main component, (ii) 40 to 80% by weight of inorganic powder, and (iii) methyl An acrylic resin premix is described which comprises 1 to 25% by weight of fine resin particles insoluble in methyl methacrylate and having a swelling degree of 3 to 15 times methacrylate.

Japanese Laid-Open Patent Publication (JP-A) No. 7-188505 discloses "acrylic syrup A" comprising (i) an unsaturated monomer composed mainly of methyl methacrylate and a polymer composed mainly of a polymer of methyl methacrylate as its main component. A premix of acrylic resin comprising 100 parts by weight of a substrate, (ii) 180 to 260 parts by weight of "inorganic powder B" and (iii) 60 to 140 parts by weight of "resin particle C" containing an inorganic powder, wherein Resin particles C are insoluble in methyl methacrylate and exhibit 40-100% by weight of oil absorbency after one day in methyl methacrylate and up to two times swelling in methyl methacrylate.

However, in Japanese Unexamined Patent Application (JP-B) No. 5-13899, a methacrylic base resin powder having an average molecular weight of 50,000 to 200,000 is used as the resin component, therefore, the surface adhesion after kneading and aging is remarkable, and after kneading There is a problem with handleability that the form stability is not sufficient and the kneading resin flow is deformed if it is left alone.

In addition, any premixes described in Japanese Patent Application (JP-A) 5-32720 and Japanese Patent Application (JP-A) 7-188505 contain an unsaturated monomer component mainly composed of methyl methacrylate, The evaporation of methyl methacrylate cannot be suppressed, there is a lack of stability when stored or left, and there is a further odor. Therefore, improvements have been demanded not only in terms of handling but also in terms of working environment.

The inventors have made considerable research on resin compositions suitable for the preparation of artificial marble, which are excellent in handleability, do not generate an odor upon handling and can be easily molded. Eventually, an unsaturated monomer having at least two double bonds or a mixture of the unsaturated monomer and the unsaturated monomer copolymerizable with the unsaturated monomer, inorganic filler, crosslinked resin particles, resin having methyl methacrylate units, which can cause radical polymerization, and It has been found that resin compositions each containing a specific amount of radical polymerization initiator are excellent in handleability, do not generate an odor upon handling, and can be easily molded to prepare artificial marble. The present invention has been accomplished based on the above findings.

Thus, the present invention provides a resin composition comprising the following components:

10 to 40% by weight of (a) an unsaturated monomer having at least two double bonds capable of causing radical polymerization or (ii) a mixture of said unsaturated monomer and an unsaturated monomer copolymerizable with said unsaturated monomer,

(b) 50 to 85 weight percent of an inorganic filler,

(c) 1 to 20% by weight of the crosslinked resin particles,

(d) 0.1 to 20% by weight resin with methyl methacrylate units, and

(e) 0.01 to 5% by weight radical polymerization initiator.

The present invention further provides an artificial marble obtained by heating and curing the resin composition.

The invention further provides a process for the preparation of artificial marble, in which the composition is heated at a temperature of 30 to 80 ° C. to give a compound in the form of clay, which is then thermally compressed at 80 to 200 ° C.

The resin composition of the present invention comprises the following components:

10 to 40% by weight of (a) an unsaturated monomer having at least two double bonds capable of causing radical polymerization or (ii) a mixture of said unsaturated monomer and an unsaturated monomer copolymerizable with said unsaturated monomer,

(b) 50 to 85 weight percent of an inorganic filler,

(c) 1 to 20% by weight of the crosslinked resin particles,

(d) 0.1 to 20% by weight resin with methyl methacrylate units, and

(e) 0.01 to 5% by weight radical polymerization initiator.

In the present invention, examples of unsaturated monomers having two or more double bonds which may affect radical polymerization include allyl methacrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene Glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexane diol di (meth ) Acrylate, neopentyl glycol di (meth) acrylate, divinylbenzene, diallyl phthalate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth ) Acrylates and the like. As used herein, the term "(meth) acrylate" refers to both acrylates and methacrylates. Of these, unsaturated monomers having two or more methacryloxy groups are preferred because only a small amount of the unsaturated monomers which have not reacted in the curing step remains.

In the present invention, unsaturated monomers copolymerizable with unsaturated monomers having two or more double bonds capable of causing radical polymerization can be used together with the electron unsaturated monomers and are not limited as long as they have copolymerizable properties, and can be appropriately selected for use. have. Examples of unsaturated monomers copolymerizable with unsaturated monomers having two or more double bonds which can cause radical polymerization are esters of methacrylic acid or acrylic acid with aliphatic, aromatic, cycloaliphatic alcohols such as methyl (meth) acrylate, ethyl (meth ) Acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl ( Meth) acrylate, benzyl (meth) acrylate and cyclohexyl (meth) acrylate; (Meth) acrylic based monomers such as hydroxyalkyl esters such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; Unsaturated acids such as acrylic acid and methacrylic acid; Styrene based monomers such as styrene and α-methylstyrene; Unsaturated nitriles such as acrylonitrile and methacrylonitrile; Monofunctional unsaturated monomers such as maleic anhydride, phenylmaleimide, cyclohexylmaleimide and vinyl acetate. Of these, esters of methacrylic acid are preferred.

In the present invention, a mixture of unsaturated monomers having two or more double bonds capable of causing radical polymerization and unsaturated monomers copolymerizable with said unsaturated monomers preferably has two or more double bonds capable of causing radical polymerization for this mixture. At least 50% by weight of the unsaturated monomer. The content of unsaturated monomers having two or more double bonds which can cause radical polymerization in the mixture is more preferably 55 to 99.9% with respect to the mixture.

Unsaturated monomers having two or more double bonds capable of causing radical polymerization, and unsaturated monomers copolymerizable with the above unsaturated monomers may also be used in a mixture of two or more, respectively.

Unsaturated monomers having two or more double bonds and / or unsaturated monomers copolymerizable with the unsaturated monomers capable of causing radical polymerization can be used while dissolving the resin of the methyl methacrylate unit of the present invention.

Hereinafter, these unsaturated monomers are referred to as "unsaturated monomers" unless otherwise specified.

The content of the unsaturated monomer in the resin composition of the present invention is in the range of 10 to 40% by weight based on the resin composition.

If the content is less than 10% by weight, sufficient moldability is not obtained in molding the resin composition, on the other hand, if the content is more than 40% by weight, the adhesion of the surface is remarkable and it is difficult to maintain the form after kneading, Therefore, handling is undesirably poor in both cases.

If the inorganic filler is insoluble in unsaturated monomers and does not interfere with its polymerization, this is not particularly limited in the present invention.

Examples of inorganic fillers include, but are not limited to, inorganic particles such as aluminum hydroxide, aluminum oxide, calcium carbonate, calcium silicate, calcium sulfate, particles including magnesium hydroxide, silica, talc, clay or bentonite, and glass fibers such as Fiber comprising alkali glass or non-alkali glass. Particles comprising aluminum hydroxide and mixtures of particles and glass fibers are preferably used as inorganic fillers.

When inorganic particles are used as the inorganic filler, particles containing aluminum hydroxide, magnesium hydroxide or silica are preferred in view of the appearance and physical properties of the obtained artificial marble.

The particle size of the inorganic particles is preferably 5 to 100 μm. If the particle size is less than 5 μm, the viscosity of the resin composition tends to be very high in mixing or molding, which is not preferable. On the other hand, when the particle size is greater than 100 μm, physical properties such as the strength of the artificial marble obtained deteriorate undesirably. However, for the purpose of giving a pattern to the obtained artificial marble, inorganic particles having a particle size of more than 100 μm can be used in the resin composition.

The content of the inorganic filler in the resin composition of the present invention is in the range of 50 to 85% by weight based on the resin composition. If the content is less than 50% by weight, marbled appearance and texture cannot be obtained from the obtained artificial marble, and if the content is more than 85% by weight, it is difficult to disperse the filler uniformly in the resin component upon mixing, which is undesirable.

Crosslinked resin particles are used in the resin composition of the present invention, examples of which are obtained by pulverizing a resin particle obtained by polymerization such as emulsion polymerization, suspension polymerization and dispersion polymerization, and a crosslinked resin polymer obtained by other polymerization into pieces. Resin particles.

The crosslinked resin particles of the present composition are not completely dissolved in a solvent such as acetone, which can swell and dissolve the polymethylmethacrylate. Crosslinked resin particles made of methyl methacrylate in an amount of at least about 50% by weight of methyl methacrylate relative to the resin particles are preferably used.

When polymerizing a mixture of at least about 50% by weight of methyl methacrylate and an unsaturated monomer to obtain its resin particles or polymers thereof, for example, in addition to unsaturated monomers having two or more double bonds that can cause radical polymerization Crosslinked resin particles can be obtained.

The average particle size of the crosslinked resin particles is usually in the range of 1 to 100 μm. When crosslinked resin particles having a particle size of more than 100 μm are used, the shape of the particles is remarkable after molding. However, the particle size is not particularly limited in order to give the artificial marble obtained a pattern such as a granular appearance.

The amount of crosslinked resin particles is 1 to 20% by weight based on the resin composition. If the amount is less than 1% by weight, the viscosity of the composition is remarkable and the handleability deteriorates. On the other hand, when the amount is more than 20% by weight, the formability of the composition decreases and the handleability deteriorates.

Resins with methyl methacrylate units are used in the resin composition of the invention, and resins with methyl methacrylate units are homopolymers of methyl methacrylate, or unsaturated copolymerizable with methyl methacrylate monomers and methyl methacrylate. The copolymer containing a monomer is shown.

Examples of unsaturated monomers copolymerizable with methyl methacrylate include, but are not limited to, esters of aliphatic, aromatic, cycloaliphatic alcohols with methacrylic acid or acrylic acid, such as methyl (meth) acrylate, ethyl (meth) acrylate , Propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylic Latex, benzyl (meth) acrylate and cyclohexyl (meth) acrylate; (Meth) acrylic based monomers such as hydroxyalkyl esters such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; Unsaturated acids such as acrylic acid and methacrylic acid; Styrene based monomers such as styrene and α-methylstyrene; Unsaturated nitriles such as acrylonitrile and methacrylonitrile; Monofunctional unsaturated monomers such as maleic anhydride, phenylmaleimide, cyclohexylmaleimide and vinyl acetate; Multifunctional unsaturated monomers with multiple double bonds that can cause radical polymerization such as allyl methacrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexane diol di (meth) acrylate, neopentyl glycol Di (meth) acrylate, divinylbenzene, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate and tetramethylolmethane tetra (meth) acrylate.

The content of the resin having methyl methacrylate units in the resin composition of the present invention corresponds to the range of 0.1 to 20% by weight based on the resin composition. If the content is less than 0.1% by weight, the morphology of the composition is weak and the handleability deteriorates. On the other hand, when the content is more than 20% by weight, the viscosity significantly increases in the mixing of the resin composition, and the mixing becomes difficult.

A radical polymerization initiator is used in the resin composition of the present invention, which performs the polymerization and curing of the unsaturated monomer.

Examples of radical polymerization initiators include azo compounds such as 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4,4-trimethylpentene), 2,2'-azo Bis (2-methylpropane), 2-cyano-2-propylazoformamide, 2,2'-azobis (2-hydroxy-methylpropionate), 2,2'-azobis (2-methyl -Butylonitrile), 2,2'-azobisisobutylonitrile, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] and dimethyl-2,2'-azo Bis (2-methylpropionate); Diacyl and / or dialkyl peroxide based initiators such as dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, benzoyl peroxide and lauroyl peroxide; Peroxy ester based initiators such as t-butyl peroxide-3,3,5-trimethyl hexanoate, t-butyl peroxyl laurate, t-butyl peroxy isobutyrate, t-butyl peroxy acetate, di-t- Butyl peroxyhexahydro terephthalate, di-t-butyl peroxy azelate, t-butyl peroxy-2-ethyl hexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethyl hexano Ate and t-amyl peroxy-2-ethyl hexanoate; Percarbonate based initiators such as t-butyl peroxy allyl carbonate and t-butyl peroxyisopropyl carbonate; Peroxy ketal based initiators such as 1,1-di-t-butyl peroxy cyclohexane, 1,1-di-t-butyl peroxy-3,3,5-trimethylcyclohexane and 1,1-di-t- Hexyl peroxy-3,3,5-trimethylcyclohexane.

The content of the polymerization initiator in the resin composition of the present invention corresponds to 0.01 to 5% by weight based on the resin composition. When the content is less than 0.01 part by weight, radical polymerization requires a long time, and when the content is more than 5 parts by weight, the unsaturated monomer cannot be gradually polymerized.

In the present invention, a polymerization initiator having a decomposition temperature such as a 10 hour half-life temperature is in the range of 60 to 100 ° C is preferable. When the temperature is less than 60 ° C., radical polymerization can be caused by mixing the resin composition or storing or transporting the so-called compound and mixed resin composition.

Two or more radical polymerization initiators can be used in combination.

The resin composition of the present invention contains a surfactant having elemental phosphorus. The inclusion of a surfactant with elemental phosphorus improves the uniformity upon mixing of the resin composition.

In particular, surfactants are effective when they contain large amounts of inorganic fillers.

Examples of surfactants having elemental phosphorus include phosphate monoesters represented by Formula 1 and phosphate diesters represented by Formula 2:

RO (CH ₂ CH ₂ O) _n P (O) (OH) ₂

[RO (CH ₂ CH ₂ O) _n ] ₂ P (O) OH

In the general formulas (1) and (2), each R represents an alkyl group or alkylphenol having 8 to 30 carbon atoms, and each n represents an average mole number of added ethylene oxide and represents 1 to 10.

Surfactants with elemental phosphorus are used in amounts of 0.01 to 5% by weight relative to the resin composition of the present invention. If the amount is less than 0.01 part by weight, the viscosity is high at the time of mixing, and on the other hand, if the amount is more than 5 parts by weight, the properties of the resin composition such as water resistance will deteriorate.

The resin composition of this invention contains a mold release agent, a ultraviolet absorber, dye, a pigment, a polymerization inhibitor, a chain transfer agent, antioxidant, a flame retardant, a binder, a reinforcing agent, etc. further.

The resin composition is obtained in the form of a slurry or gluten by mixing with the unsaturated monomer, inorganic filler, crosslinked resin particles, resin with methyl methacrylate units, radical polymerization initiator, and optionally with surfactant with elemental phosphorus. .

At the time of mixing, the resin having a methyl methacrylate unit is previously dissolved in an unsaturated monomer, and then preferable in view of the uniformity of the resin composition to be mixed, but mixed under conditions in which the resin is suspended in the unsaturated monomer or the whole components are mixed appropriately. It is also possible to run

In the following, a method for producing artificial marble is described by molding the resin composition of the present invention.

The method for producing the artificial marble includes (i) mixing and aging the resin composition of the present invention, and (ii) polymerizing and curing the resulting composition.

In the mixing and aging step of the resin composition, the unsaturated monomer, the inorganic filler, the crosslinked resin particles, the resin having methyl methacrylate units, the radical polymerization initiator, and optionally, the surfactant having atomic phosphorus and the like are finally mixed. One resin composition is obtained. Examples of this step include mixing the unsaturated monolayer, inorganic filler, crosslinked resin particles, resin with methyl methacrylate units, radical polymerization initiator, and optionally, surfactant with atomic phosphorus to obtain a slurry of the resin composition. Thereafter, the slurry is aged in a suitable container. There is no particular restriction on the container and no particular restriction on its material provided it does not dissolve or corrode by said unsaturated monomer.

When the resin composition after mixing is in the form of a slurry, it is possible to use a cell composed of two or more flat plates in contact with each other and a sealing material for sealing the surroundings as a container for sealing the resin composition. The material of the plate is not particularly limited and must not dissolve or be corroded by the unsaturated monomers. Usually, a glass plate, a metal plate, etc. are used. In the case of a metal plate, a continuous plate can be used in the form of a belt. In addition, the release thin film is previously laid on the inner surface of the cell or the inner bag is inserted into the cell.

When the resin composition is in the form of gluten and has high viscosity after mixing, the resin may be packed in a thin film, inserted into a bag, or put in a container equipped with a lid or the like. By mixing the resin composition having a high viscosity, a known mixing device such as a kneader can be advantageously used. When the resin composition is contained in a container or the like, treatment such as defoaming under reduced pressure can be performed.

The mixed resin composition can be enclosed in a container or the like and heated to 30 to 80 ° C for aging. During aging, the unsaturated monomer can be impregnated with the added crosslinked resin particles and the resin with methyl methacrylate units can be dissolved in the unsaturated monomer. The appearance of the resin composition changes from slurry form to clay form during aging, and a soft material, which is a soft material, can be used as the material to be molded.

When heating the mixed resin composition above 80 ° C, the polymerization and / or curing reaction may be undesirably initiated due to the added radical polymerization initiator. In the case where the mixed resin composition is aged at a temperature of less than 30 ° C., aging requires a long time and is not preferable. Therefore, the aging temperature is preferably in the range of 30 to 80 ° C.

The aging conditions are selected according to the composition of the resin composition, in particular, the type of crosslinked particles used, the composition of the unsaturated monomer, and the like, provided that the unsaturated monomer can be impregnated with the added crosslinked resin particles. The higher the temperature, the shorter the time required for aging. The time required for aging depends on the resin composition, in particular the type of crosslinked particles used, the composition of the unsaturated monomer, and the like, and is usually about 1 to 50 hours. Completion of the aging can be recognized, for example, by measuring the hardness of the mixed and aged resin composition. After completion of the aging, a so-called compound can be obtained from the resin composition in the form of clay.

The mixing apparatus for mixing the resin composition has a temperature control action, and the mixing and heating of the resin composition can be performed simultaneously with the mixing and aging of the resin composition. At this time, a known kneading apparatus such as a two screw extruder, a universal mixing apparatus, or a banbury mixer can be used as the kneading apparatus.

After the mixing and aging step, the polymerization and curing steps can be carried out. In the polymerization and curing step, the clay compound to be molded may be injected, compressed, heated, molded and cured into various types of molds to obtain shaped articles of various types.

Any method of molding can be used as long as the compound is compressed, heated, molded and cured to obtain shaped articles of various forms. Examples thereof include pressure molding, injection molding, transfer molding, and the like.

In the case of carrying out pressure molding, a pressure molding apparatus including a pressure-using unit and a mold must be used. The temperature of the mold in the press molding ranges from 80 to 200 ° C. The temperature on the mold surface side in contact with the compound may be the same as the temperature on the opposite surface side of the mold, or there may be a difference between these temperatures provided the difference is less than about 20 ° C.

Mold compression pressures typically range from about 20 to 130 kg / cm ² . If the pressure is less than 20 kg / cm ² , undesirable disadvantages such as surface discoloration are likely to occur on the surface of the molded article. On the other hand, if the pressure is above 130 kg / cm ² , the compound may undesirably flow out of the mold.

Molding conditions, such as the temperature of the mold, the mold compression pressure, the ratio of mold compression and the place where the compound is added to the mold, are selected according to the shape of the molded article and the time period required for the production time of the resulting artificial marble.

When performing injection molding or transfer molding, an injection molding apparatus or a transfer molding apparatus including an injection unit and a mold compression unit is used.

Suitable screws used for measurement or injection have a pressure ratio of 1.5 or less. The screw has a non-return valve having various structures on the top.

The temperature of the cylinder covering the screw and the temperature of the transfer pipe of the transfer molding are preferably adjusted to 60 ° C or less. If the temperature is above 60 ° C., a local temperature increase may occur due to the generation of shear heat in the pipe between the screw and the cylinder or during the transfer and, undesirably, may initiate the curing reaction.

When performing injection molding or transfer molding, the temperature of the mold is adjusted in the range of 80 to 200 ° C. The temperature of one mold surface may be the same as the temperature of the other mold in the pair of molds, or there may be a difference between these temperatures provided the difference is less than about 20 ° C.

The mold compression pressure and the gap between the molds can be constantly adjusted, or can be adjusted continuously or gradually as the curing reaction proceeds.

The molding conditions of the injection molding and the transfer molding are selected according to the shape of the molded article and the time required for producing the resulting artificial marble.

As mentioned above, the reaction temperature of 80-200 degreeC is preferable with respect to shaping | molding and hardening reaction in this invention. If the temperature is below 80 ° C., the curing reaction requires a long time and is industrially disadvantageous. On the other hand, when the temperature is above 200 ° C., decomposition and coloring may occur or undesirably, it is difficult to obtain advantageous shaped articles.

The time for the molding and curing reaction in the present invention is usually about 1 to 20 minutes, and the time is influenced by the type and amount of the radical polymerization initiator used, the type and amount of the unsaturated monomer, the thickness of the molded article and the temperature of the mold surface. Usually, the thinner the molded article and the higher the temperature of the mold, the shorter the time required for the molding and curing reaction.

The resin composition of the present invention is excellent in handleability, does not generate odor, and can be molded easily to obtain artificial marble.

Example

The following examples further illustrate the invention in detail but do not limit the scope thereof.

Evaluation is as follows.

(1) handleability of compound:

The hardness after aging is measured and evaluated by a rubber hardness tester according to the Japanese Standards Association JIS-K6301 method.

(2) smell:

The 50 × 50 × 3 mm compound is left under a 40 ° C. environment and first the weight loss of the compound over 1 hour, ie the volatile ratio is measured and evaluated. Numerically, the ratio is expressed as grams per square centimeter per hour (g / cm ² / hr).

Example 1

70 parts by weight of methyl methacrylate, neopentyl glycol dimethacrylate (NK ester NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.) in a 500 ml round bottom flask, 21.8 parts by weight JP-A) 7.8 parts by weight of particles obtained by the method described in No. 5-155907, Example 4 as crosslinked particles, aluminum hydroxide (CW-325, manufactured by Sumitomo Chemical Co., Ltd.) 60 Parts by weight, glass fiber (RES03-BM31, manufactured by Nippon Sheet Glass Co., Ltd.), 1.5 parts by weight and polymerization initiator (KAYACARBON BIC-75, manufactured by Kayaku AKZO Corp.) 8.2 parts by weight of a syrup prepared by dissolving 30 parts by weight of polymethyl methacrylate (SUMIPEX MH, manufactured by Sumitomo Chemical Co., Ltd.) was added to 0.15 parts by weight, and the resulting mixture was stirred and mixed to obtain a resin composition in the form of a slurry.

The resin composition is poured into a cell comprising a glass plate (thickness 5 mm) carrying the pasted polyethylene on the inner surface of the glass plate and a gasket made of vinyl chloride resin sandwiched between the glass plates so that the gap therebetween is 3 mm, It is left in a hot air dryer at 60 ° C. for 5 hours for aging. After cooling the composition to room temperature, the glass plate is removed to give the compound in the form of clay.

This compound has a rubber hardness of 25 and a volatility (weight loss) ratio of 0.0012 g / cm ² / hr.

120 g of the compound is then placed in a 120 × 120 × 20 mm plate mold and thermocompressed for 30 minutes under 120 ° C. temperature and mold compression pressure of 70 kg / cm ² .

The appearance after molding is excellent without cracks.

Example 2

13.3 parts by weight of neopentyl glycol dimethacrylate (NK ester NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.), 3 parts by weight of methyl methacrylate, in Japanese Laid-Open Patent Publication (JP-A) 5-155907 in a 1 liter round bottom flask 6 parts by weight of particles obtained by the method, Example 4, 6 parts by weight of polymethyl methacrylate (SUMIPEX MH, manufactured by Sumitomo Chemical Co., Ltd.), 70 parts by weight of aluminum hydroxide (CW-325, manufactured by Sumitomo Chemical Co., Ltd.) , 1.5 parts by weight of glass fiber (RES03-BM31, manufactured by Nippon Sheet Glass Co., Ltd.), 0.12 parts by weight of a polymerization initiator (KAYACARBON BIC-75, Kayak Arc Co., Ltd.) and a surfactant (PHOSPHANOL RS-710, Toho Chemical Industry Co., Ltd.) 0.3 parts by weight), and the resulting mixture is stirred and mixed to obtain a resin composition in the form of a slurry.

The resin composition is poured into a cell comprising a glass plate (thickness 5 mm) carrying the pasted polyethylene on the inner surface of the glass plate and a gasket made of vinyl chloride resin sandwiched between the glass plates so that the gap therebetween is 3 mm, It is left in a hot air dryer at 60 ° C. for 5 hours for aging. After cooling the composition to room temperature, the glass plate is removed to give the compound in the form of clay.

This compound has a rubber hardness of 33 and a volatility (weight loss) ratio of 0.0006 g / cm ² / hr.

In this example, the resin composition in slurry form can be easily poured into the cell as compared with the resin composition in Example 1.

Then, thermocompression molding is carried out using this compound in the same manner as in Example 1 to prepare artificial marble.

Appearance after molding is excellent without cracks.

Example 3

Except for using 13.3 parts by weight of diethylene glycol dimethacrylate (NK ester NPG, manufactured by Shinnakamura Chemical Co., Ltd.) instead of neopentyl glycol dimethacrylate, the same procedure as in Example 2 was carried out to obtain a compound in the form of clay. do.

This compound has a rubber hardness of 28 and a volatility (weight loss) ratio of 0.0008 g / cm ² / hr.

Appearance after molding is excellent without cracks.

Example 4

In a laboratory mill made by Toyo Seiki Co., Ltd., 10.6 parts by weight of neopentyl glycol dimethacrylate (NK ester NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.), 4 parts by weight of methyl methacrylate, and Japanese Patent Laid-Open (JP-A) 11 parts by weight of particles obtained by the method described in No. 5-155907, Example 4 as a crosslinked particle, 6.3 parts by weight of a copolymer of methyl methacrylate and styrene (10:90), aluminum hydroxide ( CW-325, manufactured by Sumitomo Chemical Co., Ltd., 60 parts by weight, glass fiber (RES03-BM31, manufactured by Nippon Sheet Glass, Inc.), 7.9 parts by weight, polymerization initiator (KAYACARBON BIC-75, manufactured by Kayaku Arc Irradiation Co., Ltd.), 0.36 parts by weight, and surfactant ( 0.24 parts by weight of PHOSPHANOL RS-710 manufactured by Toho Chemical Co., Ltd. is mixed to obtain a resin composition in the form of a gluten.

The resin composition is encapsulated in a bag made of polyethylene and degassed under 80 mm Hg for 3 minutes. In addition, the gap of the bag is sealed and left to stand in a hot air dryer at 60 ° C. for 7 hours for aging. After cooling the composition to room temperature, the compound is obtained in the form of clay.

This compound has a rubber hardness of 33 and a volatility (weight loss) ratio of 0.0022 g / cm ² / hr.

Then, thermal compression molding is performed in the same manner as in Example 1 to prepare artificial marble.

Appearance after molding is excellent without cracks.

Comparative Example 1

13.3 parts by weight of methyl methacrylate is carried out in the same manner as in Example 2 except for using neopentyl glycol dimethacrylate instead. The fluidity is lost during stirring and no uniform mixing is possible. The resulting mixture can be poured into the cell.

The resin composition is sandwiched between a glass plate (thickness 5 mm) and a glass plate carrying the pasted polyethylene on the inner surface of the glass plate, and the periphery thereof is sealed with a gasket made of vinyl chloride resin. Furthermore, it is left to stand in a hot air dryer for 5 hours at 60 degreeC. After cooling the composition to room temperature, the glass plate is removed to yield the compound.

This compound has a rubber hardness of 15, a volatility (weight loss) ratio of 0.012 g / cm ² / hr and gives off an odor of methyl methacrylate.

Then, thermal compression molding is performed in the same manner as in the first embodiment. If the mold is open, many cracks are observed in the resulting molded article.

The resin composition comprising the component of the present invention is excellent in handleability, does not generate odor and can be easily molded to obtain artificial marble.

Claims (14)

Resin composition containing the following components: 10 to 40% by weight of (a) an unsaturated monomer having at least two double bonds capable of causing radical polymerization or (ii) a mixture of said unsaturated monomer and an unsaturated monomer copolymerizable with said unsaturated monomer, (b) 50 to 85 weight percent of an inorganic filler, (c) 1 to 20% by weight of the crosslinked resin particles, (d) 0.1 to 20% by weight resin with methyl methacrylate units, and (e) 0.01 to 5% by weight radical polymerization initiator. The resin composition according to claim 1, further comprising a surfactant having (f) elemental phosphorus in addition to the components (a) to (e). The resin composition according to claim 1 or 2, wherein the unsaturated monomer having two or more double bonds capable of causing radical polymerization is an unsaturated monomer having two or more methacryloxy groups. The resin composition according to claim 1 or 2, wherein the unsaturated monomer having two or more double bonds capable of causing radical polymerization is neopentyl glycol dimethacrylate. The resin composition according to claim 1 or 2, wherein the unsaturated monomer having two or more double bonds capable of causing radical polymerization is an ester of methacrylic acid. The resin composition according to claim 1 or 2, wherein the inorganic filler is particles containing aluminum hydroxide. The resin composition according to claim 1 or 2, wherein the inorganic filler is a mixture of particles and glass fibers comprising aluminum hydroxide. The resin composition according to claim 1 or 2, wherein the crosslinked resin particles have an average particle size of 1 to 100 µm. The resin composition according to claim 1 or 2, wherein the crosslinked resin particles are made of methyl methacrylate in an amount of about 50% by weight or more based on the resin particles. The resin composition of Claim 1 or 2 in which a polymerization initiator has a 10 hour half life temperature of 60-100 degreeC. The unsaturated monomer having at least two double bonds capable of causing radical polymerization is an unsaturated monomer having at least two methacrylicoxy groups, and at least two double bonds capable of causing radical polymerization are used. The unsaturated monomer having is an ester of methacrylic acid, the inorganic filler is a mixture of particles containing aluminum hydroxide and glass fibers, the crosslinked resin particles having an average particle size of 1 to 100 μm, and the crosslinked resin particles having about 50 to the resin particles. A resin composition comprising at least weight percent methylmethacrylate and the polymerization initiator has a 10 hour half life temperature of 60 to 100 ° C. Artificial marble obtained by heating and curing the resin composition according to claim 1, 2 or 11. A process for producing artificial marble comprising the steps of: (i) mixing and aging the resin composition of claim 1, 2 or 11; and (ii) polymerizing and curing the resulting composition. A method for producing artificial marble, wherein the resin composition according to claim 1, 2 or 11 is heated at a temperature of 30 to 80 ° C. to obtain a compound in clay form, and then the compound is thermocompressed at 80 to 200 ° C.