JP2001146453A - Artificial stone plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial stone plate suppressed in molding defect such as crack, having sufficient basic performance, excellent in design and having high-class feeling. SOLUTION: This artificial stone plate is obtained by uniformly dispersing granular natural stone into a matrix and the matrix is formed of a matrix material comprising a matrix resin and filler and the matrix resin consists essentially of a chain transfer agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an artificial stone slab.

[0002]

2. Description of the Related Art Artificial stone slabs are molded products in which a large number of granular natural stones are dispersed in a matrix, and have an appearance that can be easily recognized as high-grade natural stone slabs such as marble and granite. Have been. Unlike natural stone slabs, artificial slabs have the basic properties of excellent heat resistance, high strength such as compressive strength and bending strength, high impact resistance and surface hardness, low water absorption, and low scratch resistance. Boards, counters, vanities, walls,
It is suitably used for floors, partitions, and the like.

[0003] In such an artificial stone plate, a bulk molding compound (BMC) is obtained by kneading granular natural stone with a matrix resin and a filler constituting a matrix by a kneader, and then the BMC is heated and heated in a mold. It can be obtained by pressing and molding to obtain a plate-like molded product, and further by polishing this surface.

Japanese Patent Application Laid-Open No. 3-150244 discloses that a compound containing a thermosetting resin, a filler, and a particulate natural stone of 20 mm or less has a curing catalyst, a low shrinkage agent,
An artificial slab obtained by molding and hardening BMC containing at least one kind of additive consisting of a fiber reinforcing material having a thickness of 25 mm or less and a thickener is disclosed. This artificial stone plate is a molded product in which a thermosetting resin, a low-shrinking agent, a filler, etc. are cured to form a matrix, in which granular natural stone is dispersed, and a BMC is formed using a thickener. By improving the flowability, the moldability is enhanced so that the designability is not impaired.

However, in such artificial stone slabs, the compatibility between the granular natural stone and the thermosetting resin or the like forming the matrix is relatively poor, and the artificial stone slab is designed to be more similar to natural stone to enhance the design. In addition, it is necessary to increase the use amount of the granular natural stone, and when molding the BMC obtained by kneading the thermosetting resin or the like with the granular natural stone, heat is generated when the thermosetting resin or the like is cured, and the heat shrinks. As a result, uneven curing is caused to cause partial distortion of the molded product, so that molding defects such as cracks are apt to occur, and there has been a problem that basic performance, design properties, and high-grade appearance are reduced.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and suppresses molding defects such as cracks, has sufficient basic performance, is excellent in design, and has a high quality feeling. It is an object of the present invention to provide an artificial slab having:

[0007]

The present invention relates to an artificial slab in which granular natural stones are dispersed in a matrix, wherein the matrix is formed from one containing a matrix resin and a filler. The matrix resin is
It is an artificial stone plate that contains a chain transfer agent as an essential component.

[0008] The present invention is also an artificial slab in which granular natural stones are dispersed in a matrix, wherein the matrix is formed from a matrix resin and a filler, and constitutes the matrix resin. It is an artificial stone plate in which the maximum heat generation temperature of the thermosetting resin is 150 to 205 ° C. Hereinafter, the present invention will be described in detail.

[0009] In the artificial stone slab of the present invention, granular natural stones are dispersed in a matrix. The matrix is formed from a material containing a matrix resin and a filler. The one containing the matrix resin and the filler means a composition for forming the matrix, and the composition is formed by being kneaded with a particulate natural stone and then molded as described in detail below. Is formed. The matrix resin contains a chain transfer agent as an essential component.

The matrix resin contains a thermosetting resin and, if necessary, a low-shrinking agent. The thermosetting resin is not particularly limited as long as it can be used as a molding material. Examples thereof include unsaturated polyester resins, vinyl ester resins (epoxy acrylate resins), (meth) acrylic syrups, diallyl phthalate resins, and the like. Radical polymerization type resins; epoxy resins, urea resins, melamine resins and the like. These may be used alone,
More than one species may be used in combination. Among these, unsaturated polyester resins are preferable because the basic performance such as the strength and surface hardness of the artificial stone plate is improved.

The unsaturated polyester resin is not particularly limited. For example, a polymer having a weight average molecular weight (Mw) of several hundreds to several tens of thousands obtained by condensing an acid component and an alcohol component is converted into a vinyl monomer. Examples thereof include a radical polymerization type resin obtained by dissolution. The acid component is not particularly restricted but includes, for example, unsaturated dibasic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, mesaconic acid, citraconic acid, citraconic anhydride; phthalic acid, anhydride Phthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, heptic acid, methyltetrahydrophthalic anhydride, endomethylenetetrahydro Saturated dibasic acids such as phthalic anhydride; and trifunctional or higher polybasic acids such as trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic dianhydride. These may be used alone or in combination of two or more.

The alcohol component is not particularly restricted but includes, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol,
Triethylene glycol, neopentyl glycol,
1,3-butanediol, 1,4-butanediol,
Glycols such as 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, propylene oxide adduct of bisphenol A, and ethylene oxide adduct of bisphenol A; trifunctional or higher alcohols such as glycerin, trimethylolpropane, and pentaerythritol; Epoxides such as ethylene oxide, propylene oxide, and epichlorohydrin are exemplified. These may be used alone or in combination of two or more.

The vinyl monomer is a reactive monomer, and is not particularly limited as long as it cross-links with the unsaturated group of the polymer at the time of molding. For example, styrene, α-methylstyrene, vinyltoluene, Chlorostyrene, vinyl acetate, allyl alcohol, ethylene glycol monoallyl ether, propylene glycol monoallyl ether, acrylonitrile, maleimides; unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and unsaturated monocarboxylic acids thereof Monoesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid, and monoesters of these unsaturated dicarboxylic acids; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene Glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate,
Polyfunctional (meth) acrylates such as trimethylolpropane tri (meth) acrylate and pentaerythritol tetra (meth) acrylate; divinylbenzene, diallyl phthalate, diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate and the like. Further, for example, a (meth) acrylic polymer having an unsaturated group in a side chain, such as obtained by reacting a (meth) acrylic polymer having a carboxyl group with a glycidyl acrylate (meth) acrylate, or the like, may also be used. Can be used. These may be used alone or in combination of two or more.

The types and amounts of the acid component, the alcohol component, and the vinyl monomer in the unsaturated polyester resin are not particularly limited, and may be, for example, in accordance with the basic performance required for an artificial stone plate or an unsaturated polyester resin. May be set appropriately. Further, the acid component, and
The method for condensing the alcohol component is not particularly limited. For example, reaction conditions such as a reaction temperature and a reaction time may be appropriately set in the same manner as described above. The polymer may be modified with various components such as a diene compound such as dicyclopentadiene and a rubber component such as a terminal-functional butadiene-acrylonitrile copolymer.

The vinyl ester resin is not particularly limited. For example, radical polymerization obtained by dissolving a reaction product obtained by addition polymerization of a vinyl unsaturated carboxylic acid at the terminal of an epoxy resin into a vinyl monomer is used. Mold resin and the like.

The epoxy resin is not particularly restricted but includes, for example, bisphenol type, novolak type, cycloaliphatic type and epoxidized polybutadiene type.

The vinyl unsaturated carboxylic acid is not particularly restricted but includes, for example, acrylic acid and methacrylic acid. The vinyl monomer is not particularly limited, and includes, for example, styrene, vinyl toluene, methyl methacrylate, vinyl acetate, chlorostyrene, diallyl phthalate, triallyl isocyanurate and the like.
These may be used alone or in combination of two or more.

The types and amounts of the epoxy resin, the vinyl unsaturated carboxylic acid and the vinyl monomer in the vinyl ester resin are not particularly limited, and are, for example, required for artificial stone plates and vinyl ester resins. What is necessary is just to set suitably according to basic performance etc. The method of addition polymerization of the epoxy resin and the vinyl unsaturated carboxylic acid is not particularly limited, and for example, reaction conditions such as a reaction temperature and a reaction time may be appropriately set in the same manner as described above.

The (meth) acrylic syrup is not particularly limited, and is, for example, a mixture containing a monomer (meth) acrylate, a polymer of (meth) acrylate, and a crosslinking agent. Yes, as needed
A radical polymerization type resin further containing the above-mentioned vinyl monomer is exemplified.

The above (meth) acrylate is not particularly restricted but includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Lauryl (meth) acrylate, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate and the like. Also,
(Meth) acrylamide can also be used. These may be used alone or in combination of two or more. Among them, methyl methacrylate or (meth) acrylic acid containing methyl methacrylate as a main component, since the basic properties such as weather resistance and surface gloss, appearance, and safety of the artificial stone plate can be further improved. Esters are preferred.

The (meth) acrylic acid ester polymer can be obtained by polymerizing the above (meth) acrylic acid ester and, if necessary, those containing a vinyl monomer as a monomer component. The polymerization degree of the (meth) acrylic acid ester polymer is not particularly limited.

The crosslinking agent is not particularly restricted but includes, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, neopentyl glycol. Multifunctional (meth) acrylates such as di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate; divinylbenzene, diallyl phthalate, diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate And the like. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester, the polymer of the (meth) acrylic acid ester, the crosslinking agent, and the kind and amount of the vinyl monomer used as required in the (meth) acrylic syrup are particularly specified. The present invention is not limited thereto, and may be set as appropriate according to, for example, basic performance required for an artificial stone plate or (meth) acryl syrup.

When the thermosetting resin contains two or more kinds of resins and forms a mixture, the content of each resin is not particularly limited. When a radically polymerizable resin is used as the thermosetting resin, a radically polymerizable resin other than the aforementioned radically polymerizable resin may be contained.

The above-mentioned low-shrinkage agent in the above-mentioned matrix resin is not particularly limited as long as it improves the dimensional stability of the artificial stone plate to be obtained. For example, polyethylene, polypropylene, polystyrene, three-dimensionally crosslinked polystyrene, polymethacrylic Examples include methyl acid, polyethylene glycol, polypropylene glycol, cellulose butyrate, acetate (acetylcellulose), polyvinyl chloride, polyvinyl acetate, polycaprolactone, and saturated polyester. These may be used alone,
Two or more kinds may be used in combination. Among these, a saturated polyester is preferable.

The above matrix resin may further contain other additives as necessary. The other additives are not particularly limited, for example, a curing agent, a thickener, an internal mold release agent, a colorant, a polymerization inhibitor, an ultraviolet absorber,
Examples include a viscosity reducing agent, a coupling agent, and an antibacterial agent. These may be used alone or in combination of two or more.

The curing agent is not particularly restricted but includes, for example, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy octoate and t-butyl peroxy octoate. Butylperoxybenzoate, cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, bis (4-
t-butylcyclohexyl) peroxydicarbonate, 1,1-bis (t-hexylperoxy) -3,
Organic peroxides such as 3,5-trimethylcyclohexane;
Examples include radical polymerization initiators such as azo compounds such as 2,2'-azobisisobutyronitrile and 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile.

The thickener is not particularly restricted but includes, for example, polyvalent metal oxides such as magnesium oxide, calcium oxide and zinc oxide; polyvalent metal hydroxides such as magnesium hydroxide, calcium hydroxide and aluminum hydroxide. Products; polyfunctional isocyanates and the like.

The internal release agent is not particularly limited.
Examples include stearic acid, zinc stearate, aluminum stearate, calcium stearate, barium stearate, stearic acid amide, lauric acid, triphenyl phosphate, alkyl phosphate, and the like. Further, generally used release agents such as waxes and silicone oil can also be used. The colorant is not particularly limited, and includes, for example, inorganic pigments, organic pigments, and toners that can be used in thermosetting resins.

The polymerization inhibitor is not particularly limited.
For example, pt-butylcatechol, p-methoxyphenol, hydroquinone, p-benzoquinone, chloranil, m-dinitrobenzene, nitrobenzene, p-phenyldiamine, sulfur, diphenylpicrylhydrazyl,
Di-p-fluorophenylamine, tri-p-nitrophenylmethyl and the like.

The ultraviolet absorber is not particularly limited, and for example, those which can be used for thermosetting resins such as benzophenone type and benzotriazole type can be used. The viscosity reducing agent, the coupling agent, and the antibacterial agent are not particularly limited, and for example, those that can be used for a thermosetting resin can be used.

The filler constituting the matrix of the artificial slab of the present invention is preferably one containing aluminum hydroxide as an essential component, since the basic performance such as the strength of the artificial slab is improved. May be included. The other components are not particularly limited, for example, calcium carbonate, calcium sulfate, barium sulfate,
Inorganic fillers such as alumina, clay, talc, milled fiber, silica (silica sand), river sand, diatomaceous earth, mica powder, gypsum, and glass powder; organic fillers, and fiber reinforcing materials. These may be used alone or in combination of two or more.

The fiber reinforcing material is not particularly limited.
For example, inorganic fibers such as glass fibers, carbon fibers, metal fibers, and fibers made of ceramic; organic fibers made of aramid, polyester, and the like; and natural fibers. Further, the form of these fibers is not particularly limited, and examples thereof include roving, chopped strand, mat, cloth (woven fabric), and the like.

The granular natural stone dispersed in the matrix of the artificial slab of the present invention is not particularly limited as long as the natural stone is granulated. Also, pottery, porcelain, glass,
What made granular glass etc. can also be used.

The material of the natural stone is not particularly limited. Examples thereof include igneous rocks such as granite and andesite; sedimentary rocks such as sandstone and tuff; metamorphic rocks such as marble, slate, and serpentine; No. These may be used alone or in combination of two or more. Among them, granite is preferable because the artificial stone plate has excellent surface hardness and chemical resistance. The granite is not particularly limited, and examples thereof include granites such as Fujioka Mikage and Manari Mikage, mahogany, Belfast, Verdefontan and the like. The particle size range of the granular natural stone is not particularly limited, and is preferably 30 mm or less, more preferably 1 to 3.
15 mm. If it exceeds 15 mm, in kneading,
There is a possibility that breakage and abrasion of the granular natural stone cannot be suppressed. Moreover, there is a possibility that the kneading machine may be damaged. Furthermore, since the fluidity of BMC becomes inferior, workability at the time of manufacture falls and there is a possibility that filling to a metallic mold may become insufficient in a molding process. Further, the maximum particle size is preferably 20 mm or less. More preferably, it is 13 mm or less.

The particle size distribution of the granular natural stone is not particularly limited. For example, when a plate having a thickness of 13.5 mm is formed, the following particle size distribution is preferable. Particles having a particle size of 6 mm or more: 0 to 15% by weight Particles having a particle size of 5 mm to less than 6 mm: 0 to 30% by weight Particles having a particle size of 4 mm to less than 5 mm: 5 to 30% by weight Particles having a particle size of 3 mm to less than 4 mm: 5 Particles having a particle size of 2 to less than 3 mm: 10 to 50% by weight Particles having a particle size of 1 to 2 mm: 5 to 50% by weight Particles having a particle size of less than 1 mm: 0 to 10% by weight The total amount is 100% by weight.

If the distribution of the particles having a particle size of 5 mm or more exceeds the above range, the kneading machine may be damaged at the time of kneading during the production of the artificial slab, and the fluidity of the BMC is inferior. The workability may be reduced, and the filling into the mold may be insufficient. If the ratio of particles having a particle size of less than 1 mm exceeds 10% by weight, blackening may occur on the artificial stone plate, and 1 mm or more When the distribution of particles having a particle size of less than 5 mm exceeds the above range, the particle size becomes nearly uniform, and the pattern of the granular natural stone formed on the surface of the artificial slab becomes difficult to approximate natural stone.

The average particle size of the granular natural stone is not particularly limited, but is preferably 3 to 8 mm. 3m
When it is less than m, the particle size distribution becomes nearly uniform, and the pattern of the granular natural stone formed on the surface of the artificial stone plate may be difficult to approximate natural stone. If it exceeds 8 mm, there is a possibility that breakage or abrasion of the granular natural stone cannot be suppressed in the kneading step. Moreover, there is a possibility that the kneading machine may be damaged. Furthermore, since the fluidity of BMC and the like is inferior, the workability at the time of production is reduced, and the filling in the mold in the molding step may be insufficient.
More preferably, it is 4 to 7 mm. The type of the particulate natural stone and the state of the particles are factors that determine the appearance and basic performance of the artificial stone plate of the present invention, and can be appropriately selected according to the use of the artificial stone plate to be obtained.

In the present specification, the maximum grain size of the granular natural stone is defined as the maximum grain size b that passes through a sieve having a mesh size of (b + d) mm (where d> 0) and remains on a bmm sieve.
mm. In the present specification, the particle size distribution of the granular natural stone means, for the granular natural stone before being put into the kneading machine, means the distribution of the particle size of each particle constituting the granular natural stone, the horizontal axis is the particle size, the vertical axis Can be expressed by the weight ratio (% by weight) of the particles having each particle size. The particle size distribution can be measured according to the sieving method of JIS Z8815. In the present specification, the average particle size means a representative particle size. In the case where the horizontal axis represents the particle size and the vertical axis represents the weight ratio (% by weight) of the particles having each particle size, and represents the particle size distribution of the granular natural stone, the direction of the particle size increases from the minimum particle size. The weight ratio (% by weight) of each particle size is accumulated, and the total is 50% by weight.

The method for producing the artificial stone slab of the present invention is not particularly limited. For example, the above-mentioned components are kneaded by a kneader to form a BMC, and if necessary, extruded by an extruder to form a flat plate. And a method of polishing the surface of a flat plate. In order to form BMC after kneading each of the above-mentioned components with a kneading machine, it may or may not be aged at room temperature.

The above-mentioned kneading method is not particularly limited. For example, first, a part or all of the matrix resin is prepared with a stirrer such as a disperser, then charged into a kneader such as a kneader and kneaded, and then the remaining components are kneaded. Are sequentially charged into a kneader such as a kneader and kneaded to perform kneading. Further, the order of charging the above-described components to the kneader is not particularly limited.

The molding method is not particularly limited. For example, BMC is charged (charged) into a heated mold,
A pressure molding method such as press molding (compression molding) for curing by pressing, and the like can be given. The heating temperature of the mold is not particularly limited, but is preferably from 100 to 170C. Further, the upper mold and the lower mold may be at the same temperature or different temperatures. The molding time during which the mold is pressed is not particularly limited, but is preferably 180 to 700 seconds. If the heating temperature is less than 100 ° C. or the molding time is less than 180 seconds, the composition for the artificial slate may not be sufficiently cured, and if it exceeds 700 seconds, it is not economical. If the heating temperature exceeds 170 ° C., the basic performance, design, and luxury of the artificial slab may be reduced.

The surface polishing method is not particularly limited, and examples thereof include a method of performing continuous polishing or uniaxial polishing with a wet polishing machine in the same manner as the method of polishing the surface of natural stone. Thereby, the surface of the flat plate obtained by molding can be polished by 0.5 to 2.0 mm, and the pattern of the granular natural stone in the matrix in the obtained artificial slab becomes clearer than that before polishing. Performance is improved.

In the production of the artificial slab of the present invention, the types and amounts of the components, the filler and the granular natural stone in the matrix resin, the combination thereof, the molding conditions for molding the artificial slab, or What is necessary is just to set suitably according to the basic performance requested | required of an artificial stone board, its use, etc., Although it does not specifically limit, In the usage-amount of the said low shrinkage agent in the said matrix resin, 100 weight part of thermosetting resins On the other hand, the amount is preferably set to 0 to 50 parts by weight. If it exceeds 50 parts by weight, the basic performance such as the strength of the artificial slab may be reduced. The amount of the thickener used in the matrix resin can be appropriately set according to the weight average molecular weight and the viscosity of the thermosetting resin.

The amount of the filler is preferably 30 to 300 parts by weight based on 100 parts by weight of the matrix resin. If the amount is less than 30 parts by weight, the basic performance such as the strength of the artificial slab may be reduced. If the amount is more than 300 parts by weight, the fluidity of the BMC may be inferior and the workability during production may be reduced. In the filler, the aluminum hydroxide is preferably 50 to 100% by weight based on the total amount of the filler. 50
When the amount is less than the weight%, the basic performance such as the strength of the artificial slab may be reduced. More preferably, it is 70 to 100% by weight.

It is preferable that the use amount of the above-mentioned granular natural stone is 50 to 1000 parts by weight based on 100 parts by weight of the matrix resin. If the amount is less than 50 parts by weight, the basic performance such as the strength and surface hardness of the artificial slab and the design may be reduced. If the amount exceeds 1000 parts by weight, the fluidity of BMC is inferior and the filling property during molding is poor. It may decrease. More preferably, it is 300 to 800 parts by weight.

In the artificial slab of the present invention, it is preferable that the amount of the granular natural stone dispersed in the matrix is 30 to 90% by weight based on the total amount of the artificial slab. When the content is less than 30% by weight, the basic performance such as the surface hardness of the artificial stone plate may be reduced, or the design of the granular natural stone formed on the surface of the artificial stone plate may be reduced, so that the design property may be reduced. If it exceeds 90% by weight, the fluidity when molding BMC is reduced, and the basic performance such as the strength of the artificial stone plate may be reduced.

In the production of artificial stone slabs, it is necessary to use a large amount of granulated natural stones in order to improve the design of the artificial stone slabs, which are relatively poorly compatible with the matrix resin, and to enhance the design properties of the artificial stone slabs as being more similar to natural stones. In addition, when molding a BMC obtained by kneading a matrix-forming composition and granular natural stone, a heat is generated when the matrix resin is cured, and the molded product is partially distorted due to heat shrinkage. Therefore, molding defects such as cracks and cracks are likely to occur. Artificial stone slabs with such molding defects will have reduced basic performance,
Moreover, the design and the sense of quality are impaired.

In the present specification, “excellent in design”
And, the granular natural stone dispersed in the matrix,
By exhibiting various colors, shapes, patterns, and the like, it is meant that the appearance of the artificial stone plate such as a pattern or pattern formed on the surface gives a good impression to a viewer. In addition, "having a high-class feeling" means that the particulate natural stone dispersed in the matrix,
By the matrix having sufficient transparency, it means that the same high-grade feeling as natural stones such as granite and marble inherent to the granular natural stones appears on the surface of the artificial stone plate. In artificial stone slabs, if the design is excellent and has a luxurious feeling,
If there is a molding defect such as cracks or cracks, the appearance of the pattern or pattern formed on the surface, the design is reduced because it does not give a good impression to the viewer, and the transparency of the matrix is also reduced. Therefore, the sense of quality is impaired.

Therefore, in the production of artificial stone slabs, BM
In order to suppress molding defects such as cracks when molding C, it is conceivable to reduce the molding temperature and lengthen the molding time to suppress heat generation when the thermosetting resin is cured. However, in such a method, since internal strain cannot be sufficiently suppressed, occurrence of molding defects such as cracks cannot be sufficiently suppressed. Further, since the molding time becomes longer, the productivity is reduced.

In the present invention, the matrix resin contains a chain transfer agent as an essential component. We have:
As a result of intensive studies, the matrix resin contains the chain transfer agent as an essential component, thereby suppressing heat generation when the matrix resin is cured, suppressing heat shrinkage and internal strain caused by the heat, and In order to cure uniformly, it was found that the occurrence of molding defects such as cracks was suppressed, and furthermore, interfacial separation between the matrix resin and the granular natural stone was reduced, and the curability of the matrix resin was reduced by the chain transfer agent. It is found that the curing of the matrix resin can be completed because the curing does not stop even if the value is adjusted, and the present invention has been completed.

Examples of the chain transfer agent include α-methylstyrene dimer and carbon tetrachloride. Thiol compounds include alkyl mercaptans such as t-butyl mercaptan, n-octyl mercaptan and n-dodecyl mercaptan; Aromatic mercaptans such as naphthol; thioglycolic acid; alkyl esters of thioglycolic acid such as octyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris- (thioglycolate) and pentaerythritol tetrakis- (thioglycolate); β-mercaptopropionic acid; octyl β-mercaptopropionate,
1,4-butanediol di (β-thiopropionate), trimethylolpropane tris- (β-thiopropionate), pentaerythritol tetrakis- (β
-Thiopropionate) and the like, and β-mercaptopropionic acid alkyl esters. These may be used alone or in combination of two or more. Among them, α-methylstyrene dimer is preferable, since when molding an artificial slab, molding defects such as cracks can be sufficiently suppressed.

The amount of the chain transfer agent is preferably 0.01 to 5% by weight based on the total amount of the matrix resin. If the amount is less than 0.01% by weight, molding defects such as cracks may occur in the artificial stone plate obtained by molding, and if it exceeds 5% by weight, the curability of the matrix resin may be inferior. More preferably, it is 0.05 to 2% by weight, still more preferably 0.1 to 2% by weight.
1 to 1% by weight.

The artificial stone slab of the present invention is characterized in that when molding a BMC obtained by kneading a composition forming a matrix and granular natural stone, the entire compound in a heated mold is uniformly cured. Molding defects such as cracks are suppressed, and curing is completed. Therefore, the artificial slab of the present invention exhibits sufficient basic performance even when the consistency between the granular natural stone and the matrix resin is relatively poor or when it is necessary to use a large amount of the granular natural stone. Can be. The artificial slab of the present invention suppresses molding defects such as cracks, and thus contributes to the improvement of the appearance. Therefore, the artificial slab is excellent in design and has a high-class feel.

A second artificial stone plate of the present invention is an artificial stone plate in which granular natural stones are dispersed in a matrix, wherein the matrix is formed from one containing a matrix resin and a filler. The maximum heat generation temperature of the thermosetting resin constituting the matrix resin is 150 to 205 ° C
(The measurement temperature is 80 ° C.).

As a result of intensive studies, the present inventors have found that the maximum heat generation temperature of the thermosetting resin constituting the matrix resin is 150 to 205 ° C., thereby suppressing the heat shrinkage when the matrix resin is cured. In addition, it is found that the internal strain caused by it is suppressed, and the whole is hardened uniformly, so that the occurrence of molding defects such as cracks is suppressed, and further, the interface peeling between the matrix resin and the granular natural stone is reduced. Moreover, even when the maximum heat generation temperature of the thermosetting resin constituting the matrix resin is within the above range, it has been found that the curing of the matrix resin can be completed, and the second invention has been completed. .

In the second invention, the matrix resin contains a thermosetting resin and a curing agent as essential components, and if necessary, a chain transfer agent and the like. The thermosetting resin that constitutes the matrix resin includes a thermosetting resin and a curing agent that constitute the matrix resin as essential components. If the matrix resin contains a chain transfer agent, it contains a chain transfer agent. The maximum exothermic temperature means the maximum exothermic temperature when the thermosetting resin constituting the matrix resin is measured in accordance with the method for measuring high-temperature curing characteristics of JIS K6901. The maximum exothermic temperature was determined by placing 50 g of thermosetting resin in a test tube, fixing the test tube in a thermostat kept at 80 ° C., and measuring the temperature of the thermosetting resin in the test tube. Is the temperature when. The thermosetting resin used here is a thermosetting resin and a curing agent constituting the thermosetting resin, and a constituent weight ratio of a chain transfer agent included as necessary is a thermosetting resin constituting the matrix resin. Is the same as
The thermosetting resin constituting the matrix resin whose maximum heat generation temperature is within the above range is, for example, the type and amount of the thermosetting resin contained in the matrix resin, the curing agent and the chain transfer agent contained in the matrix resin. Appropriate factors related to the maximum heat generation temperature of the thermosetting resin that constitutes the matrix resin, such as the type and amount used, the ratio of the amount of the thermosetting resin contained in the matrix resin to the curing agent or chain transfer agent and the amount used, etc. It can be obtained by setting.

The second artificial stone plate of the present invention is obtained by kneading a matrix-forming composition and granular natural stone.
When molding the MC, the entire compound in the heated mold is uniformly cured, whereby molding defects such as cracks are suppressed, and the curing is completed. Therefore, the artificial stone slab of the second present invention has sufficient basic performance even when the consistency between the granular natural stone and the matrix resin is relatively poor or when it is necessary to use a large amount of the granular natural stone. Can be demonstrated. Since the artificial stone slab of the second invention is one in which molding defects such as cracks are suppressed, it contributes to improving the appearance,
It will be excellent in design and will have a high-class feeling.

The artificial stone slab of the first invention and the artificial stone slab of the second invention have excellent heat resistance and strength, such as compressive strength and bending strength, because cracks and other molding defects are suppressed. It has basic properties such as high impact resistance and high surface hardness, low water absorption and low scratch resistance, and also has excellent design properties, and granite, granite, marble, and any other natural stone Even when used as a natural stone, the luxury of the natural stone can be exhibited on its surface, and architectural decoration materials such as tiles and wall panels; bathtubs (bathtubs), vanities (counters), sinks (sinks) , Bathroom panels, system kitchen tops (kitchen counters), tabletops and other household equipment; various ornaments, nameplates, and the like.

[0060]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Note that “parts” indicates “parts by weight”.

Preparation Example 1 In a four-necked flask as a reactor equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 980 parts of maleic anhydride as α, β-unsaturated dibasic acid, After charging 3,360 parts of ethylene oxide 2-adduct of bisphenol A as a polyhydric alcohol, the inside of the flask was replaced with nitrogen gas. Next, the mixture was stirred while the maximum temperature was 215.
C., and the dehydration reaction was performed for a predetermined time. Thus, an unsaturated polyester having an acid value of 17 was obtained. Then, resin A-1 was obtained by mixing 70 parts of this unsaturated polyester, 30 parts of styrene as a vinyl monomer, and 0.02 parts of hydroquinone as a stabilizer.

Preparation Example 2 A four-necked flask as a reactor equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer was charged with 1660 parts of isophthalic acid as a saturated dibasic acid and dicarboxylic acid as a polyhydric alcohol. After charging 1380 parts of propylene glycol, the inside of the flask was replaced with nitrogen gas. Next, the mixture was heated to a maximum temperature of 215 ° C. while stirring, and a dehydration reaction was performed for a predetermined time. As a result, a saturated polyester having an acid value of 12 was obtained. And this saturated polyester 60
By mixing 40 parts of styrene as a vinyl monomer and 0.02 part of hydroquinone as a stabilizer, a resin B-1 was obtained.

Example 1 As a thermosetting resin, an unsaturated polyester resin A-
185 parts, 15 parts of saturated polyester resin B-1 as a low-shrinking agent, KBM-5 as a coupling agent
03 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.): 2 parts, chain transfer agent: 0.5 part of α-methylstyrene dimer, tinuvin 320 (trade name, manufactured by Ciba Specialty Chemicals): 0.5 part Then, 0.1 part of parabenzoquinone as a polymerization inhibitor and 0.3 part of AT-3 (trade name, manufactured by Dainichi Seika Co., Ltd.) as a colorant were charged into a container, and the mixture was stirred for 10 minutes by a disper.

Thereafter, Perhexa TMH was used as a curing agent.
2.0 parts (trade name, manufactured by NOF CORPORATION) were added, and the mixture was further stirred by a disper for 10 minutes to prepare a matrix resin.

Next, the total amount of the prepared matrix resin,
Heidilite H which is aluminum hydroxide as filler
200 parts of -320 (trade name, manufactured by Showa Denko KK) and 250 parts of Fujioka Mikage as granular natural stone were put into a kneader in which a ceramic chip was adhered to a kneading wing and the inner wall of a container, and the kneader was rotated and kneaded for 1 minute. Thereafter, with the kneader rotated, 20 parts of chopped strand ECS06B-144 / P (trade name, manufactured by Nippon Electric Glass Co., Ltd.) as a reinforcing glass fiber as a filler, and zinc stearate as an internal mold release agent. After 2.0 parts of SZ-2000 (trade name, manufactured by Sakai Chemical Industry Co., Ltd.) was charged and kneaded for 1 minute, the kneader was stopped, and 250 parts of the same granular natural stone as described above was charged. After kneading for 20 minutes, the same reinforcing glass fiber
And kneaded for another 2 minutes. The kneaded material is taken out of the kneader and 400 mm × 400 mm (about 8 kg)
BMC was obtained by pre-form packing to the dimensions shown in FIG. The particle size distribution of Fujioka Mikage used was 4% by weight of particles having a particle size of 6 mm or more, 16% by weight of particles having a particle size of 5 mm or more and less than 6 mm, and 24% by weight of particles having a particle size of 4 mm or more and less than 5 mm. 28% by weight of particles having a particle size of 3 mm or more and less than 4 mm, 20% by weight of particles having a particle size of 2 mm or more and less than 3 mm, 7% by weight of particles having a particle size of 1 mm or more and less than 2 mm, and less than 1 mm The particle size was 1% by weight.

The obtained BMC was sized at 135/130 ° C. using a 2500 ton large-sized hydraulic press machine,
BM preformed in a 70 mm x 2470 mm mold
Six C sheets were charged by a BMC charging machine with a charge pattern of one horizontal row, and press-molded at a pressure of 7.8 MPa for 420 seconds to obtain a molded product having a thickness of about 13.5 mm.
Next, the surface of the molded product was polished by about 1 mm with a wet-type surface polishing device for natural stone to obtain an artificial stone plate. The obtained artificial slab was evaluated by the method described below. The results are shown in Table 1.

[0067]Evaluation method  (1) Visual evaluation test for molding defects such as cracks Mold defects such as cracks on the surface of the obtained artificial stone plate
Was visually evaluated according to the following criteria. A: No molding defects such as cracks are observed. ：: Insufficient molding such as minute cracks that are difficult to visually confirm
Is observed. Δ: Molding defects such as small cracks are observed. ×: Molding defects such as large cracks are observed. (2) Bending strength test The bending strength of the obtained artificial stone slab was measured in accordance with JIS K 6911.
It measured according to.

Comparative Example 1 An artificial slab was obtained in the same manner as in Example 1 except that no chain transfer agent was used. The obtained artificial slab was evaluated by the method shown in Example 1. The results are shown in Table 1.

[0069]

[Table 1]

Example 2 The thermosetting resin constituting the matrix resin used in Example 1 was measured for the maximum heat generation temperature in accordance with JIS K 6901. That is, the composition is 85 parts of A-1, 2 parts of perhexa TMH, and 0.5 part of α-methylstyrene dimer, and has a high-temperature curing characteristic of 80 ° C. (maximum heat generation temperature).
Was measured. The results are shown in Table 2. Table 2 shows the results of a visual evaluation test and a bending strength test of molding defects such as cracks evaluated in Example 1 for the artificial stone slab obtained in Example 1.

Comparative Example 2 The thermosetting resin constituting the matrix resin used in Comparative Example 1 was measured for the maximum heat generation temperature in accordance with JIS K 6901. That is, the composition was 85 parts A-1 and 2 parts perhexa TMH, and the high-temperature curing characteristics at 80 ° C. (maximum exothermic temperature) were measured. The results are shown in Table 2.
Table 2 shows the results of the visual evaluation test and the bending strength test of molding defects such as cracks evaluated in Comparative Example 1 for the artificial slab obtained in Comparative Example 1.

[0072]

[Table 2]

As is clear from Tables 1 and 2, in Examples 1 and 2, an artificial stone plate obtained by using a matrix resin containing a chain transfer agent as an essential component, or a thermosetting resin constituting the matrix resin The artificial stone slab obtained using a matrix resin having a maximum heat generation temperature of 150 to 205 ° C. of the base resin has sufficient basic performance since molding defects such as cracks are not observed, and is excellent in design,
It had a high-class feeling.

On the other hand, in Comparative Examples 1 and 2, the maximum exothermic temperature of the artificial stone plate obtained by using the matrix resin containing no chain transfer agent or the thermosetting resin constituting the matrix resin is not in the above range. The artificial stone plate obtained by using the matrix resin was observed to have molding defects such as cracks, had some basic performance, and had designability, but was inferior to that obtained in Example 1. .

[0075]

The artificial slab of the present invention has the above-described structure, which suppresses molding defects such as cracks and completes the curing of the matrix resin, and therefore has sufficient basic performance. Yes, and excellent in design,
It has a sense of quality.

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Claims (3)

[Claims] 1. An artificial slab in which granular natural stones are dispersed in a matrix, wherein the matrix is formed from a matrix resin and a filler.
The artificial stone board, wherein the matrix resin contains a chain transfer agent as an essential component. 2. The artificial stone slab according to claim 1, wherein the chain transfer agent is an α-methylstyrene dimer. 3. An artificial slab in which granular natural stones are dispersed in a matrix, wherein the matrix is formed from a matrix resin and a filler.
An artificial stone plate, wherein the thermosetting resin constituting the matrix resin has a maximum heat generation temperature of 150 to 205 ° C.