JPH04201526A - Manufacture of artificial marble - Google Patents

Abstract

PURPOSE:To obtain a molded product having a stable marble pattern, good transparent or depth feelings, and excellent surface smoothness by appropriately sharing a first and second resin composites having different transparency into small parts, and dispersing and then injecting them, and after stirring lightly, curing them at an ordinary temperature or under heating conditions. CONSTITUTION:A first resin composite containing unsaturated polyester resin, an inorganic filling material, and a curing agent, and a second resin composite being different in their transparent degree are prepared separately. In the next place, they are dispersion injected into a mold in small parts respectively so as to depict desired marble patterns, and after mixing gently therein, they are hardened in order to obtain a desired artificial marble.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing artificial marble, and more specifically, the present invention relates to a method for producing artificial marble, and more specifically, a resin composition having an unsaturated polyester resin as a matrix resin is cast-molded at room temperature or under heating. The present invention relates to a method for stably producing artificial marble having a marble pattern with excellent transparency or depth.

(Prior Art) Conventionally, molded products made by curing liquid unsaturated polyester resin compositions containing fillers, curing agents, etc., have been used as artificial marble for so-called sanitary products such as bathtubs, kitchen counters, washstands, etc. Widely used for wall materials, etc.

Conventionally, such artificial marble is produced by degassing a base color resin mixture in a stirrer, and then mixing one or more patterned resin mixtures in a vacuum with the same degassing treatment. It is manufactured by injecting this mixture into a mold and curing the mixture at room temperature or under heating. Also,
Degas the resin mixture for the base color in a stirrer, take it out of the stirrer, and add one or more resin mixtures that have been degassed in the same way.For the patterned seeds, add the resin mixture and use a spatula etc. It is also produced by stirring, pouring into a mold, and curing the mixture at room temperature or under heat.

However, the former method not only cannot reproduce the flow pattern of natural marble, but also requires cleaning the inside of the stirrer after each molding process. It requires craftsmanship, and the pattern is not stable and often contains air bubbles.

(Problems to be Solved by the Invention) The present invention was made in order to solve the above-mentioned problems in the production of conventional artificial marble. An object of the present invention is to provide a method for manufacturing artificial marble having a stable marble flow pattern and having excellent transparency or depth by a molding method.

(Means for Solving the Problems) The method for producing artificial marble according to the present invention includes a first resin composition containing an unsaturated polyester resin, an inorganic filler, and a hardening agent, and a second resin composition having a different transparency from this resin composition. The resin composition is prepared separately, each of these is divided into small portions so as to create a desired marble pattern, dispersed and poured into a mold, stirred lightly, and then cured.

The unsaturated polyester resin is usually made by dissolving 50 to 80% by weight of unsaturated polyester in 50 to 20% by weight of a polymerizable monomer. When the unsaturated polyester content is less than 50% by weight, it is impossible to obtain artificial marble with sufficient strength, while when it exceeds 80% by weight, the moldability and workability of the resin composition tend to deteriorate. This is because there is.

An unsaturated polyester resin can generally be obtained by reacting an acid component, which is an α,β-unsaturated dibasic acid and/or its acid anhydride, with a polyhydric alcohol component.

Examples of the α,β-unsaturated dibasic acids include maleic acid, fumaric acid, itaconic acid, citraconic acid, and chlormaleic acid, and two or more of these may be used in combination. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, neopentyl glycol, 1,6-hexanediol, triethylene glycol, hydrogenated bisphenol A, and isopentyl glycol. , glycerin, trimethylolpropane, dicyclopentadiene, etc. These may also be used in combination of two or more.

In the production of unsaturated polyester resin 22, a saturated dibasic acid and/or its acid anhydride may be used in combination as the acid component, if necessary. Examples of such saturated dibasic acids include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, succinic acid, azelaic acid, adipic acid,
Examples include tetrahydrophthalic acid, hexahydrophthalic acid, chlorentiic acid, tetrachlorophthalic acid, and tetrabromophthalic acid.

On the other hand, among polymerizable monomers, unsaturated polyester resins such as styrene, vinyltoluene, divinylbenzene, α-methylstyrene, chlorostyrene, dichlorostyrene, vinyl acetate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, etc. Examples include crosslinkable vinyl monomers, divinyl monomers, vinyl oligomers, and the like. Usually, styrene is preferably used.

The unsaturated polyester resin composition used in the present invention usually contains an inorganic filler and a curing agent, and further contains a reinforcing material, a low shrinkage material, a curing accelerator, an internal mold release agent, and a thickening agent, if necessary. , colored side, etc.

Examples of inorganic fillers include calcium carbonate, magnesium carbonate, barium sulfate, talc, clay, mica, silica, alumina, glass powder, aluminum hydroxide,
Magnesium hydroxide, agar stone, silica sand, etc. are used.

Among these, glass powder and aluminum hydroxide are preferably used from the viewpoint of enhancing the transparency of the resulting artificial marble. Fillers can be used in a wide range of ways, taking into consideration workability, strength of the resulting molded product, economic efficiency, etc. - For boat fishing, it is preferable to use a ratio that provides close packing.

As a curing agent, for example, t-butyl perbenzoate,
Organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, butylperoxy-2-ethylhexanoate, 1,1-di-t-butylperoxycyclohexane, L-butylperoxyisopropyl carbonate, etc. Oxides are used. The curing agent is generally used in an amount of 0.5 to 3 parts by weight per 100 parts by weight of the unsaturated polyester resin.

Examples of the reinforcing material include glass fibers, polyester fibers, phenol fibers, polyvinyl alcohol fibers, and carbon fibers, but glass fibers are usually preferably used. These can be used in a wide range, taking into consideration the viscosity of the resin composition and the strength of the molded product obtained.

In addition, examples of low shrinkage materials include polyethylene, polystyrene, polymethyl methacrylate, polyvinyl chloride,
Thermoplastic resins such as polyvinyl acetate, polycaprolactam, and saturated polyester, polybutadiene rubber, and polystyrene-acrylonitrile copolymers are used.

As the curing accelerator, metal salts of organic acids, particularly cobalt salts, such as cobalt naphthenate, cobalt octylate, cobalt acetylacetone, etc., are used.

As the internal mold release agent, higher fatty acids such as stearic acid and zinc stearate, higher fatty acid salts, alkyl phosphates, and the like are used. Usually unsaturated polyester resin 10
It is used in a range of 0.5 to 5 parts by weight relative to 0 parts by weight.

Pigments can be used to color the resulting molded product.

It is not particularly limited as long as it does not significantly inhibit the curing of the unsaturated polyester resin. Furthermore, a defoaming side for preventing volatilization of monomers in the resin composition is also used if necessary.

According to the method of the present invention, first and second resin compositions containing the above-mentioned components together with an unsaturated polyester resin and having mutually different transparency upon curing are separately prepared. In order to obtain resin compositions with different transparency in this way,
For example, a method using unsaturated polyester resins whose refractive indexes preferably differ from each other by 0.01 or more, a method using fillers with different average particle sizes, a method using different fillers, a method combining these appropriately, etc. can be used. .

Such first and second unsaturated polyester resin compositions can be obtained by kneading the required components using a common technique in this type of technical field, for example, using a mixing machine such as a mortar mixer or a kneader. be able to.

According to the method of the invention, the first
The second unsaturated polyester resin composition is appropriately dispersed so as to create a desired marble pattern, poured into a mold, and heated at room temperature to about 150°C for the required time after stirring. By curing and releasing the molded product from the mold, it is possible to obtain artificial marble having a marble pattern with excellent transparency or depth.If necessary, in order to improve the surface properties, A gel coat layer may also be formed.

(Example) The present invention will be explained below with reference to Examples.

Examples 1 to 3 In order to obtain unsaturated polyester resin compositions with different transparency, in Example 1, unsaturated polyester resins with different refractive indexes were used (the filler was the same), and in Example 2, Fillers of the same type but different average particle sizes were used (the unsaturated polyester resins were the same), and in Example 3, different types of fillers were used (the unsaturated polyester resins were the same). In each set, the first and second molding materials were confirmed to have a difference in transparency of 3% or more by total light transmittance measurements.

As described above, as shown in Table 1, combinations of the first resin composition (1) and the second resin composition (II) with different formulations were prepared separately, and each was divided into small portions,
Approximately the same weight of the mixture was dispersed and placed in a mold for manufacturing a bathroom vanity, and after stirring lightly, the mold was clamped. After degassing by shaking for 5 minutes, at room temperature,
After this time, the molded product was removed from the mold and held for 7 minutes.
After curing at 5°C for 120 minutes, the outer diameter is 400mm x 5.
A molded product having a beautiful clear marble pattern with a diameter of 0.00 mm and a wall thickness of 7 m and a clear sense of transparency or depth was obtained.

(Effects of the Invention) According to the method of the present invention, the first and second resin compositions having different transparency are suitably divided into portions, dispersed and injected, and then cured at room temperature or under heating after being stirred. As a result, it is possible to obtain a molded product that has a stable marble pattern, is transparent or deep, and has a smooth surface.Such molded products can be used, for example, in bathtubs, kitchen counters, Suitable for manufacturing washstands, wall materials, etc.

Patent applicant Sekisui Chemical Co., Ltd. Representative Hiro 1) Kaoru

Claims (1)

[Claims] (1) Separately prepare a first resin composition containing an unsaturated polyester resin, an inorganic filler, and a curing agent, and a second resin composition having a different transparency from this resin composition, and mix them into the desired marble. Divide each into small portions to create a pattern, disperse and inject into the mold, stir lightly, and then
A method for producing artificial marble, which is characterized by hardening.