JPH02160649A - Production of acrylic artificial marble - Google Patents

Abstract

PURPOSE:To obtain acrylic artificial marble improved in impact strength by tightly mounting an impact-resistant thermoplastic resin molded product on the inner surface of a back side mold in a forming mold, injecting, polymerizing and curing an acrylic artificial marble molding material therein. CONSTITUTION:An acrylic artificial marble molding material consisting of a mixture of a polymerizable syrup consisting of methyl methacrylate and polymer thereof, artificial marble raw material inorganic powder, a polymerization initiator and, as necessary, a crosslinking agent, coupling agent, colorant, etc., is injected into a forming mold, polymerized and cured in the mold to produce artificial marble. In the process, the following operation is performed. That is a preformed impact-resistant thermoplastic resin molded product, swellable or soluble in the above-mentioned monomer and preformed according to the shape of the inner surface of a back side mold in a forming mold is tightly mounted on the inner surface of the back side mold to polymerize and cure the artificial marble molding material and simultaneously closely adhere a thermoplastic resin molded product to the back side of the artificial marble.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a method for producing acrylic artificial marble, and particularly aims to improve its impact strength.

(B) Conventional Art Acrylic artificial marble used for sinks, bathtubs, washstands, etc. has relatively low impact strength, and there is a risk of damage during product transportation, processing, and assembly! [! It is desirable to take measures to prevent product damage due to

Conventional methods include filling the back side of artificial marble with glass fibers, and filling the back side of artificial marble with FRP (fiber fibers) such as polyester resin.
lass Re1nforced Plastic
s) is known.

This FRP can be laminated by known techniques such as the hand-removal method and the spray-up method.

Taking the spray-up method as an example, it requires complex processes and many man-hours such as masking, primer application, FRP spraying, defoaming rolls, heat curing, and trimming, as well as organic solvent gas treatment equipment and wastewater treatment. Equipment and other pollution prevention measures are also required. In addition, it is difficult to prevent the workplace from becoming dirty due to resin liquid and glass fiber scattering, which stains artificial marble products, which are characterized by their beautiful appearance, and leads to the production of defective products. In addition, acrylic artificial marble often requires secondary processing such as cutting, cutting, and grinding, and in such cases, artificial marble laminated with FRP is made of relatively expensive materials such as super steel and artificial diamond. Another problem is that it significantly shortens the life of the equipment.

(C) Disclosure of the Invention The method of the present invention involves tightly fitting an impact-resistant thermoplastic resin molding, which has been preformed to match the shape of the inner surface of the back mold, onto the inner surface of the back mold in the cast polymerization of acrylic artificial marble. The method for producing an acrylic artificial marble is characterized in that the resin molding is brought into close contact with the back surface of the artificial marble at the same time as the artificial marble molding material is polymerized and cured.

The impact-resistant thermoplastic resin used in the present invention is a monomer containing 1111
11! Charpy impact strength of 15 kg*cm containing soluble resin or polyblend etc.
/c ■ 2. or more thermoplastic resin, including, but not limited to, impact-resistant grade resin such as ABS resin, vinyl chloride resin, methacrylic resin, etc., such as Stylac 301 (trade name) manufactured by Asahi Kasei Corporation ■ ), Takiflex EV (product name) made by Takiron■, RM-6 made by Chin■
761 (product name), etc.

These resins are molded in advance by a resin molding method suitable for the shape, such as extrusion molding, compression molding, blow molding, vacuum molding, etc., so that they closely fit the inner surface of the cast-polymerized back mold of artificial marble. molded.

The impact-resistant thermoplastic resin molded product formed by the above method is tightly attached to the inner surface of a back mold for cast polymerization of artificial marble. If the installation is not done tightly, there will be variations in the thickness of the artificial marble product, and in severe cases, the resin molded product will protrude from the surface of the artificial marble, resulting in a defective product, so it is important to install the product tightly. The key to tight fitting is first to mold a molded product that matches the inner dimensions of the back mold for cast polymerization, but with thermoplastic resin, a molded product that meets the purpose of the present invention can be molded using a known molding method. It is easy to do. F.R.
Because large shrinkage occurs in thermosetting resins such as P during curing, it is difficult to obtain molded products that can be tightly attached to the inner surface of the back mold in cast polymerization. Some parts do not follow the shrinkage and do not come into close contact with the artificial marble. It is easy to tightly attach the impact-resistant thermoplastic resin molding to the inner surface of the back mold that matches the inner dimensions of the back mold for cast polymerization, but if the shape is complex, small holes drilled in the back mold may be used. Use a method such as suctioning from the outside of the back mold through a tube. Another advantage of the impact-resistant thermoplastic resin molding is that its heat shrinkability allows it to follow the polymerization shrinkage of artificial marble, and it has excellent adhesion.

Syrup (A) consisting of a monomer and polymer mainly composed of methyl methacrylate used in the present invention is made by partial polymerization of a monomer mainly composed of methyl methacrylate or consisting of these monomers. The viscosity measured by a B-type viscometer obtained by dissolving the polymer, copolymer, or mixture is 30 to 20.
It is a liquid with a viscosity of 0.00 centipoise (cps).

The monomer containing methyl methacrylate as a main component consists of 50% by weight or more of methyl methacrylate, and other methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, and 2-hydroxyethyl methacrylate, methyl acrylate, Examples include acrylic acid esters such as ethyl acrylate, butyl acrylate, and 2-ethylexyl acrylate, as well as styrene, α-methylstyrene, acrylonitrile, and vinyl acetate.

The artificial marble raw material inorganic powder (B) used in the present invention is an inorganic powder that has been conventionally used for manufacturing artificial marble, and is not particularly limited. For example, aluminum hydroxide, magnesium hydroxide, etc. , calcium carbonate, cristobalite, glass powder, magnesium silicate, etc.

After uniformly mixing the artificial marble molding material including the syrup (A), the inorganic powder (B), a polymerization initiator, and if necessary a crosslinking agent, a coupling agent, and a H coloring agent, the artificial marble molding material is mixed. The air in this space is injected into the space formed between the front mold and the impact-resistant thermoplastic resin molding that is tightly installed in the back mold of the mold polymerization mold, and is expelled by the molding material. Pour from the bottom to the top.

Next, heated water is passed through a jacket installed in the mold to perform polymerization. At this time, the front mold side is first heated to polymerize, and then the back mold side is heated to complete the polymerization. Then, from the start of heating to the end of polymerization, the mold is continuously tightened in accordance with polymerization contraction.

By the method described above, it is possible to obtain an acrylic artificial marble with improved impact strength, in which the impact-resistant thermoplastic mrrii molding is adhered to the back surface of the artificial marble.

Examples of the present invention will be shown below.

(d) Examples Examples! 50 kg of α-cristobalite with an average particle size of 50 ILm was mixed with 25 kg of syrup obtained by dissolving 5 kg of a copolymer of 95% methyl methacrylate and 5% by weight of acrylic ugly methyl with an average molecular weight of 100,000 in 20 kg of methyl methacrylate, and polymerized. 100 g of bis-(4-t-butylcyclohexyl) peroxydicarbonate and 300 g of lauroyl peroxide were added as an initiator, followed by mixing and defoaming to obtain an artificial marble molding material.

On the other hand, ABS resin (Stylac 17 manufactured by Asahi Kasei Kogyo ■)
2 sheets: Charpy impact strength 28Kg・c+w/cm
”), length 70cm, width 45cm, depth 20cm
A molded article with a thickness of about 2 mm was obtained by vacuum forming it to fit the inner surface of a back mold for casting of a sink having a sink size 120 cm in total length and 55 cm in width.

Attach this molded product to the side mold for sink casting.

The surface mold was covered and fastened, and the above-mentioned artificial marble molding material was injected. Hot water at 80° C. was passed through the jacket of the surface mold while maintaining the temperature at 8 Kg/cm zG, and the polymerization was completed by holding for 60 minutes.

The Charpy impact strength of the artificial marble in which the ABS resin was adhered to the back mold was 12 kg@c/cs+2.

And, this artificial marble could be cut without any difference from artificial marble that is not covered with ABS resin.

Example 2 In the same manner as in Example 1 above, impact-resistant vinyl chloride resin (2-layer plate of Takilex EVX manufactured by Takiron: Izot impact strength 80 Kga cm/c layer notch) was adhered to a thickness of An artificial marble slab measuring 8m (500m long and 500ts wide) was manufactured.

The Charpy impact strength of the obtained flat plate was 7Kg・cm/
It was c■2.

Example 3 Methyl methacrylate 80% by weight and styrene 20% by weight/1%
3 g of lauroyl peroxide to IKg of monomer mixture of
2 kg of α-cristobalite and 15 g of t-butylperoxy 2-ethylhexanony) were added to the syrup, which was heated to 75°C and polymerized until the viscosity at 25°C as measured by a B-type viscometer became gQcps, and then rapidly cooled. The mixture was added, mixed and defoamed to obtain an artificial marble molding material.

This was prepared in the same manner as in Example 1 using ABS resin (Stylac 101 manufactured by Asahi Kasei Industries, Ltd.: Charpy impact strength 16 K).
g/am/am2) The fabricated 2 mm thick sheet is 8 mm thick, 500 mm long, and 5°01 wide.
Manufactured an artificial marble slab by C Peng.

The Charpy impact strength of the obtained flat plate was 5Kg・cml
It was c■2.

Comparative Example 1 In the same manner as in Example 1 above, a sink made only of artificial marble molding material was manufactured.

The Charpy impact strength of this sink is 2.7 Kg@cm
/cm2.

(E) Effects of the Invention The method of the present invention is as described above and has the following effects.

(1) Acrylic artificial marble having a much higher impact strength than before can be obtained without making the cutting conditions of artificial marble worse than before.

(2) There is no need for complicated post-processes like conventional FRP lamination, and the risk of defective products due to stains on the artificial marble is significantly reduced.

Furthermore, the impact-resistant thermoplastic phase-resin molded product used in the present invention can be easily manufactured using existing equipment or, in some cases, by outsourcing.

(3) The back surface of conventional acrylic artificial marble had unevenness, but in the present invention, since the impact-resistant thermoplastic resin molding is closely adhered to the back surface of the artificial marble, it is naturally smooth. Since the color, design, etc. of this resin molded product can be freely selected, a decorative effect can be expected.

Claims (1)

[Claims] A polymerizable syrup consisting of a monomer mainly composed of methyl methacrylate and its polymer, an inorganic powder of artificial marble raw material, a polymerization initiator, and if necessary a crosslinking agent, a coupling agent,
In a method of manufacturing artificial marble by injecting an acrylic artificial marble molding material consisting of a mixture of colorants etc. into a mold and polymerizing and hardening it within the mold, the back side of the mold is pre-shaped to match the shape of the inner surface of the mold. An impact-resistant thermoplastic resin molding that is swollen or soluble in the monomer is tightly attached to the inner surface of the back mold, and at the same time as the artificial marble molding material polymerizes and hardens, the thermoplastic resin molding is placed on the back surface of the artificial marble. A method for manufacturing acrylic artificial marble characterized by closely adhering.