JPH02102155A - Production of granitic artificial stone - Google Patents

Abstract

PURPOSE:To improve resistance to hot water, weather, discoloration and fouling by curing a mixture of a specific monomer mixture solution containing crushed resin particles dispersed therein with a hydrate of a metal oxide and colorant. CONSTITUTION:Crushed particles of at least one resin having a transparency or color tone different from that of a cured product obtained from a mixture solution of 20-80wt.% aliphatic (meth)acrylate [e.g., ethylene glycol di(meth) acrylate] with 80-20wt.% aromatic vinyl compound (e.g., styrene), a difference in specific gravity from the mixture solution within the range of + or -0.1 and 10-100 mesh particle diameter in an amount of 40-100 pts.wt. are mixed and dispersed in 100 pts.wt. above-mentioned monomer mixture solution. The resultant dispersion in an amount of 100 pts.wt. is then mixed with 100-800 pts. wt. hydrate of a metal hydroxide (e.g., aluminum hydroxide) having <=5mu average particle diameter and a curing agent (e.g., benzoyl peroxide), injected into a mold, precured at about 60 deg.C and postcured at 80-120 deg.C to afford a granitic artificial stone having 10-70% total light transmittance of a plate having 0.3mm thickness.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a method for manufacturing granite-like artificial stone with excellent heat resistance, particularly hot water resistance, and excellent design that can be used as housing equipment and building materials. .

(Prior Art) Artificial stone made by mixing crushed pieces of natural stone into unsaturated polyester resin and hardening it has been well known.

Furthermore, a method is widely used in which a transparent gel foot layer is provided on the surface of a molded product and crushed pieces are placed inside to bring out the stone texture of natural stone.

However, since all of these methods use crushed pieces of natural stone as decorative particles, the difference in specific gravity between the particles and the uncured resin liquid is large and the particles settle, making it difficult to uniformly disperse the particles, and also affecting the design, such as transparency and color tone. There were also restrictions on gender, and it was not possible to provide design patterns that met various tastes. In addition, the artificial stones obtained by these methods tend to undergo interfacial peeling due to insufficient adhesion between the crushed pieces and the resin, and also have problems in physical properties such as strength, durability, and stain resistance. Furthermore, the cutting process requires the same level of processing tools as those used for stone processing, and there is a drawback in that cutting and polishing can only be carried out by some specialized companies.

As a method to improve these drawbacks, a method using resin particles obtained by crushing thermoplastic resins such as acrylic resins or cured products of unsaturated polyester resins in place of crushed pieces of natural stone (Japanese Patent Laid-Open No. 59-31134) ) has been proposed.

However, with methods using thermoplastic resin particles, the particles swell or dissolve due to uncured resin liquid or polymerizable additives during molding, resulting in changes in viscosity and color tone, making stable molding impossible. Ta. In addition, the obtained molded product has the disadvantage that it is easily softened and deformed by heat at relatively low temperatures, easily erodes, has poor solvent resistance, and easily discolors and loses its luster when used in cosmetics and the like. Furthermore, hot water causes the product to whiten and become opaque in a short period of time, resulting in molded products that are difficult to use for bathtubs and washbasins.

On the other hand, the method using cured particles of unsaturated polyester resin improves processability, design, heat resistance, solvent resistance, etc.; Resistance to yellowing) and hot water resistance (whitening and opacity due to hot water) were insufficient, and a molded product that could withstand long-term use could not be obtained.

(Problems to be Solved by the Invention) In view of the above-mentioned circumstances, the present invention aims to obtain a granite-like artificial stone with improved weather resistance (yellowing) resistance, hot water resistance, stain resistance, and excellent designability. It has been done.

(Means and Effects for Solving the Problems) The present inventors have developed crushed resin particles obtained by curing a mixture of a specific monomer and a filler that differ in transparency and color tone from the crushed particles. The inventors have discovered that the above object can be achieved by dispersing the crushed particles in a mixture consisting of a specific monomer and a filler to give a cured product, and then molding and curing the mixture in which crushed particles are dispersed, and have completed the present invention. Ta.

That is, in the present invention, a mixture (I) obtained by dispersing a metal oxide hydrate in a monomer mixture containing an aliphatic polyfunctional (meth)acrylate and an aromatic vinyl compound as essential components is molded and cured. When obtaining artificial stone, aliphatic polyfunctional (meta)
The cured product of mixture (I) is obtained by curing a mixture consisting of a monomer mixture containing acrylate and an aromatic vinyl compound as essential components, a hydrate of gold B oxide, and a coloring agent if necessary, and has a high transparency. Alternatively, the present invention relates to a method for producing a granite-like artificial stone, characterized in that crushed particles of at least one resin having a different color tone are mixed and dispersed in the mixture (I).

This invention will be explained in detail below.

The method for producing the granite-like artificial stone of the present invention involves: (i) controlling the transparency or color tone of crushed resin particles to be different from those of the cured product of mixture (I); A monomer mixture containing a compound as an essential component and gold Iil! such as aluminum hydroxide! ! A mixture for producing crushed particles is prepared by appropriately changing the composition of a mixture consisting of oxide hydrates or adding various coloring agents to the mixture, and the mixture is cured to produce particles with different color tones and transparency. Step of obtaining a cured resin; (1) A step of crushing the cured resin to obtain decorative particles; (2) Preferably, the difference in specific gravity between the crushed resin particles used and the particles is ±0.0 to prevent sedimentation or floating separation in a short time. (1) A step of preparing a mixture (I) for bonding particles blended so that the particle bonding ratio is within 1, and (2) a step of mixing and dispersing the mixture (I) for bonding crushed resin particles and the crushed particles, followed by molding and curing.

The molded and cured product becomes a product as it is by demolding or by sanding the surface.

Depending on the method of mixing and dispersing the metal oxide hydrate, the mixture (I) for bonding crushed resin particles can be made into a casting mixture containing a high filler content and a low viscosity. It can also be made into a fresh bread-like mixture with excellent fluidity.

The aliphatic polyfunctional (meth)acrylates used in the present invention include ethylene glycol di(meth)acrylate-1 to
Probylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neobentyl glycol di(meth)acrylate, glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate Contains acrylate, etc.

Examples of aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, and divinylbenzene.

The ratio of the aliphatic polyfunctional (meth)acrylate to the aromatic vinyl compound is such that the more the aromatic vinyl compound is added, the more transparent the cured product will be. It is preferable to adjust within a range.

The monomer mixture in the present invention has the above two types as essential components, but various types of (meth)acrylates other than aliphatic polyfunctional (meth)acrylate such as methyl (meth)acrylate and isobutyl (meth)acrylate can also be used. (Meth)acrylate monomers can be used, and other monomers and oligomers such as various macromonomers, unsaturated polyester oligomers, fumaric acid esters, and maleimides can also be used.

Furthermore, a thermoplastic polymer may be added to the monomer mixture in order to reduce shrinkage during molding and hardening, prevent cracks and improve surface smoothness of the product.

Examples of thermoplastic polymers include (meth)acrylic polymers such as polymethyl methacrylate (meth)acrylic-styrene copolymers, polystyrene, polyvinyl acetate, styrene-vinyl acetate copolymers, polyvinyl chloride,
polybutadiene, polyethylene, polycaprolactam,
Conventionally known low shrinkage polymers such as saturated polyester can be used alone or in combination. When thermoplastic polymers for low shrinkage are blended in large quantities, the viscosity of the monomer mixture increases, making it difficult to obtain a mixture suitable for casting containing highly filled materials, and reducing the transparency and heat resistance of the product. You may end up getting only something inferior in terms of sex. Therefore, it is best to use the thermoplastic polymer for low shrinkage in as small a quantity as possible, and it is desirable to use it in an amount of 40 parts by weight or less, more preferably in the range of 5 to 30 parts by weight, per 100 parts by weight of the monomer mixture. .

Hydrates of metal oxides used in the present invention include, for example, aluminum hydroxide, magnesium hydroxide, and calcium hydroxide. Among these, it is preferable to use a hydrated metal oxide having an average particle size of 5 microns or less, as this results in a beautiful product with particularly good surface condition and particularly excellent hot water resistance.

Furthermore, it is particularly preferable that the white stone has a content of 90% or more.

In this case as well, the hydration of the metal oxide is limited to the extent that it does not adversely affect the flame retardancy of the product from which inorganic fillers such as silica, alumina, quartz, calcium silicate, calcium carbonate, talc, and clay can be obtained. It can be used in place of a part of something.

Examples of the curing agent used when curing the mixture include benzoyl peroxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, bis(
4-t-butylcyclohexyl) peroxydicarbonate, t-butylperoxybenzoate, t-butylperoxyoctoate, etc. are used. Further, the curing agent can be used alone or together with an organic amine or a polyvalent metal salt as an accelerator.

In order to specifically carry out the present invention, for example, aliphatic polyfunctional (meth)acrylate alone or a mixture with other (meth)acrylates for producing crushed resin particles 80~
A monomer mixture containing 20% by weight, preferably 70 to 30% by weight, and 20 to 20% by weight, preferably 30 to 70% by weight of an aromatic vinyl compound is prepared, and 100 to 800 parts of monomers are added to 100 parts by weight of this mixture. Disperse metal oxide hydrates. At this time, the metal oxide hydrate is treated with a silane coupling agent in advance, or the amount is equivalent to 0.1 to 2.0% based on the weight of the metal oxide hydrate used. By dissolving or dispersing the silane coupling agent in the monomer mixture and then using the gold B oxide hydrate, the water resistance of the resulting product can be improved.

Furthermore, various coloring agents can be added as necessary to change the color tone.

In addition to the metal oxide hydrate added to the monomer mixture, if necessary, various fillers, reinforcing fibers such as glass fiber, and release materials such as zinc stearate may be added to the extent that they do not impede the effects of the present invention. A molding agent, thixotropic agent, plasticizer, flame retardant, flame retardant, etc. may be added. Further, the curing agent is usually added in an amount corresponding to 0.5 to 3.0% based on the weight of the monomer mixture.

As for the dispersion method, to prepare a low-viscosity mixture for casting, a high-speed stirrer, a pigment dispersion machine for paint@A manufacturing, or a kneading roll may be used; To achieve this, a low-speed, powerful mixer such as a kneader is suitable.

The mixture thus obtained is injected, press-fitted or put into a mold and cured by various molding methods such as casting, pressing, extrusion, etc., and is used as a resin for producing crushed particles, but generally it is cast-cured. A resin is obtained. In the case of cast-curing, proceed with preliminary curing at a temperature of, for example, 60°C, and if necessary, heat up to 80°C.
It is post-cured by heating to ~120°C to become a resin for producing crushed particles.

This cured resin can be used in both transparent and opaque types, but in order to obtain a granite-like artificial stone that looks three-dimensional and has a deeper design, it is necessary to use a full-light beam with a 0.3 m thick plate. It is desirable that the transmittance is 10 to 70%.

Next, for crushing the resin, there are conventional collision crushing methods using a hammer mill, crushing methods using a crusher, etc., and the method may be selected as appropriate depending on the shape of the particles to be obtained.

The size of the crushed particles may be selected depending on the desired granite pattern, but it is usually preferable that the particles pass through a 10-mesh standard sieve but do not pass through a 100-mesh standard sieve. Large grains that do not pass through the 10 mesh or 10
With fine particles passing through 0 mesh, it is difficult to produce a clear granite pattern on the product with good reproducibility.

The resin mixture (I) for bonding crushed particles may have a composition similar to that of the mixture used for manufacturing crushed particles, but the composition may be such that the cured product has a different transparency or color tone from that of the resin for manufacturing crushed particles. prepared.

Above all, in order to make the crushed particles in the obtained artificial stone look more three-dimensional, it is desirable that the total light transmittance of the cured product of the mixture (I> in a plate with a thickness of 0.3 m is 60% or more. , to reduce the difference in specific gravity with the crushed particles, the mixture (
It is preferred to slightly increase the proportion of hydrated gold B oxide in I).

When mixing and dispersing crushed resin particles in mixture (I), the mixing ratio of both is preferably in the range of 40 to 100 parts by weight of crushed particles per 100 parts by weight of mixture (I), especially in order to obtain an appearance similar to granite. The most suitable amount is 60 to 80 parts by weight.

Further, the crushed particles added to the mixture (I) may be obtained from one type of resin, but in the case of one type of resin, the depth of the oval stone-like pattern tends to be lacking, so it is preferable to add the crushed particles to the mixture (I).
) It is preferable to use particles obtained by crushing at least one resin with good transparency and at least one resin with black color.

As a method for dispersing the crushed particles in the mixture (I), a high-speed stirrer, a pigment dispersion machine for paint production, or a cross-wire roll may be used to prepare a low-viscosity formulation for casting; In order to obtain a dough-like mixture for molding, a low-speed, powerful kneading machine such as a kneader is suitable.

The thus obtained crushed resin particles form a mixture (I).
The mixture dispersed in
It can be turned into a granite-like artificial stone product as is, or the surface can be polished and sanded.

(Effects of the invention) The granite-like artificial stone of the present invention is flame retardant, does not change in appearance such as whitening or yellowing even when immersed in boiling water for a long time, has a high heat distortion temperature, and is resistant to tobacco tests. It is an egg-shaped stone-like product with excellent design that gives excellent results in other contamination tests, and can be used with confidence even in areas where it has traditionally been difficult to use due to lack of heat and hot water resistance, such as bathtubs and kitchen counters. It is something that can be done.

(Examples) Examples will be described in more detail below, but these do not represent the entirety of the present invention.

[Manufacture of crushed resin particles]

Production Example 1 25 parts by weight of trimethylolpropane trimethacrylate, 5 parts of methicine and silane coupling agent (K
BM-503, manufactured by Shin-Etsu Chemical ■] 0.5 part by weight was mixed,
A monomer mixture was prepared. Next, 200 parts of aluminum hydroxide [Hisilite H-320, average particle size 3.5 microns, manufactured by Showa Light Metal ■] was kneaded into this mixed solution using a high-speed stirrer, and then an inner toner for acrylic resin ( AT-
3. 1.5 parts by weight of Dainichiseika Chemical Co., Ltd.) and a curing agent, Barikidox PX-16 (bis(4-t-butylcyclohexyl) peroxydicarbonate, manufactured by Nippon Kayaku ■) 0.
8 parts by weight was added and mixed, followed by defoaming under reduced pressure to obtain a mixture for particles.

Next, this mixture was poured into a casting mold of 200 x 200 x 50 m, and cured at 70°C, which cured in 30 minutes, and was further post-cured at 120°C for 2 hours. The cured product was a milky white resin that beautifully scattered light and had an astronomical stone-like translucency, and the total light transmittance of the resin on a molded plate with a thickness of 0.3 mm was 62%.

This resin was crushed with a hammer mill, coarse particles were removed with a 20 mesh standard sieve, fine particles were removed with an 80 mesh standard sieve, and particles of 20 to 80 mesh were collected, with a specific gravity of 1.75.
Particles (I) were obtained.

Production Example 2 25 parts by weight of trimethylolpropane trimethacrylate, 30 parts of methyl methacrylate, and 45 parts of Sutisine
A mixture for particles was obtained in the same manner as in Production Example 1, except that a monomer mixture consisting of heavy hanging parts was used, and it was cured to obtain a cured resin. This resin is milky white and translucent, and has a thickness of 0.3
The total light transmittance of the S plate was 48%.

This resin was crushed and classified in the same manner as in Production Example 1 to obtain particles (2) with a specific gravity of 1.75.

Production Example 3 A black toner for acrylic resin (AT-854, manufactured by Dainichi Nichiseika Kogyo ■) 2 was added to the same particle mixture as used in Production Example 2.
．． A cured resin was obtained in the same manner as in Production Example 2, except that 4 parts by weight were added and mixed as a colorant.

This resin is black and translucent, and has a thickness of 0.3 tts.
The total light transmittance through the plate was 16%.

This resin was crushed and classified in the same manner as in Production Example 1 to obtain particles (3) with a specific gravity of 1.75.

Production Example 4 A milky-white, translucent cured resin was obtained using exactly the same recipe as in Production Example 1, except that an unsaturated polyester resin was used instead of the monomer mixture.

The total light transmittance of this resin on a 0.3M thick plate was 65%.

This resin was crushed and classified in the same manner as in Production Example 1 to obtain particles (4) with a specific gravity of 1.77.

Example 1 30 heavily affected areas of trimethylolpropane trimethacrylate, 70 parts by weight of styrene and a silane coupling agent (K
Mix BM-503, Shin-Etsu Chemical special product] 0.5 overlapping part,
A monomer mixture was prepared. Next, 300 parts by weight of aluminum hydroxide (Hisilite H-320, average particle size 3.5 microns, manufactured by Showa Light Metal) was kneaded into this mixed solution using a high-speed stirrer.

Next, the hardening agent Parriki Dox PX-16 (bis(4)
0.8 parts by weight of -1-butylcyclohexyl) peroxydicarbonate (manufactured by Nippon Kayaku ITL) was added, and after mixing, defoaming was carried out under reduced pressure to obtain a mixture for particle bonding.

The viscosity of this mixture was 10 voids at a liquid temperature of 30°C, and the specific gravity was 1.76.

When this mixture was cured to form a plate with a thickness of 0.3M, the total light transmittance of the plate was 82%.

Next, 100 parts by weight of this mixture was added to the particles obtained in Production Example 1 (
I) 10 parts by weight, 20 overlapping parts of particles (2) obtained in Production Example 2 and 30 parts by weight of particles (3) obtained in Production Example 3 were added and mixed, and after defoaming, a casting mold of 1000 x 2000 x 13, s was prepared. When the resin was injected into water and cured at 60°C, it was cured in 42 minutes, and further cured at 120°C for 2 hours.

The cured product was a beautiful egg-shaped stone-like molded product in which white particles and black particles with different degrees of transparency were uniformly dispersed in a beautiful milky-white, translucent, astronomical stone-like cured resin. When the surface layer of the obtained flat plate was ground with a belt sander to about 0.5 ttm to form a product, the cross section of the particles appeared directly on the surface, resulting in an artificial stone plate with excellent decorativeness and a more three-dimensional depth. It became. The physical properties of the obtained artificial stone plate were as shown in Table 1.

Example 2 30 parts by weight of trimethylolpropane trimethacrylate, 50 parts by weight of styrene, 2011 parts of polystyrene, and 0.5 parts of a silane coupling agent (KBM-503, specially manufactured by Shin-Etsu Chemical) were mixed and dissolved, and a monomer mixture was prepared. did.

Next, 2501 parts of aluminum hydroxide (Hisilite H-320, average particle size 3.5 microns, manufactured by Showa Light Metal) was kneaded into this mixed solution using a high-speed stirrer, and then,
Add 0.8 parts by weight of Parrydox PX-16 (bis(4-t-butylcyclohexylte, manufactured by Nippon Kayaku)) as a curing agent and knead in a kneader to form a dough-like particle bonding mixture. Obtained.

Note that this mixture was coated to a thickness of 0. When press-molded into a 3 m plate, the total light transmittance of the plate was 75%.

Next, to 100 parts by weight of this bread-like mixture, 9 parts of the particles (I)4ON obtained in Production Example 1 and 1! 25 parts by weight of particles (3) obtained in J Formation Example 3 were added and further kneaded in a kneader to obtain a particle-containing raw bread-like molding material. this thing 1
Flat plate mold heated to 20℃ (cavity dimensions:
300 x 300 x 6 #Il), heated under pressure for 5 minutes, and then taken out.

The resulting molded product was a beautiful egg-shaped artificial stone plate with uniformly dispersed white and black particles. In addition, the physical properties of this artificial stone plate were as shown in Table-1.

Comparative Example 1 An artificial stone plate was obtained using the same recipe as in Example 1 except that 30 parts by weight of particles (4) obtained in Production Example 4 were used instead of particles (I) and (2).

This artificial stone plate had a beautiful oval stone appearance, but as shown in Table 1, its physical properties were unsatisfactory.

Claims (1)

[Claims] 1. Molding a mixture (I) in which a hydrate of a metal oxide is dispersed in a monomer mixture containing an aliphatic polyfunctional (meth)acrylate and an aromatic vinyl compound as essential components. When curing to obtain artificial stone, a mixture consisting of a monomer mixture containing an aliphatic polyfunctional (meth)acrylate and an aromatic vinyl compound as essential components, a hydrate of a metal oxide, and a coloring agent if necessary is hardened. A granite-like artificial stone characterized by mixing and dispersing in the mixture (I) crushed particles of at least one resin which is obtained by mixing and having a different transparency or color tone from the cured product of the mixture (I). Manufacturing method. 2. The method for producing a granite-like artificial stone according to claim 1, wherein the difference in specific gravity between the crushed particles and the mixture (I) is within ±0.1. 3. The method for producing a granite-like artificial stone according to claim 1, wherein the size of the crushed particles is such that it passes through a 10 mesh standard sieve but does not pass through a 100 mesh standard sieve. 4. Add crushed particles to 100 parts by weight of mixture (I)
The method for producing a granite-like artificial stone according to claim 1, wherein the ingredients are mixed in a proportion ranging from 0 to 100 parts by weight. 5. The granite-like artificial structure according to claim 1, wherein the crushed particles are obtained by crushing at least one resin having a different transparency from that of the cured product of the mixture (I) and at least one black resin. Stone manufacturing method. 6. The method for producing a granite-like artificial stone according to claim 1, wherein the resin for producing crushed particles has a total light transmittance of 10 to 70% in a 0.3 mm thick plate. 7. The method for producing a granite-like artificial stone according to claim 1, wherein the cured product of the mixture (I) has a total light transmittance of 60% or more on a 0.3 mm thick plate.