JPH06210649A - Production of artificial marble molding plate - Google Patents

Abstract

PURPOSE:To efficiently produce a thin artificial marble panel uniform in thickness, in producing a large artificial marble panel by pressing a granular or lumpy thermosetting compd. containing an inorg. filler under heating, by making the interval between molds in the vicinity of the central part thereof narrower than that of the peripheral part thereof by a predetermined dimension. CONSTITUTION:As a compd. 2, a granular or highly viscoelastic lumpy one composed of a thermosetting resin containing 30-80wt.% of an inorg. filler is used. At the time of hot press molding, the interval between molds 4, 4 on the sides of upper and lower hot plates 5, 5 in the vicinity of the central part thereof is made narrower than that of the peripheral part thereof by l-3mm. The adjustment of this interval is pref. performed by placing a spacer 1 formed by laminating metal foils each having a thickness of 20-60mum in a pyramidal shape and setting the height of the central part of the formed laminate to 1-3mm on the rear surface of the upper or lower mold 4 so as to deform the molds 4 at the time of pressing. This method is suitable for the production of a large thin artificial marble panel with a thickness of 6mm or less, a width of 600-1250mm and a length of 1500-4000mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an advantageous method for producing a large-sized thin plate-like artificial marble having a uniform thickness using a thermosetting resin as a binder.

[0002]

2. Description of the Related Art Conventional stone materials such as natural stone and granite are excellent in decorativeness and are therefore used in construction materials and other fields. However, natural stone materials are expensive because they are low in yield, and also have problems in workability.
Therefore, in recent years, artificial stones having a natural stone-like appearance obtained from various coloring materials, methacrylic resins containing fillers, or unsaturated polyester resins have been used for applications such as bathtubs and top plates of system kitchens. Is coming.

Such artificial marble is manufactured by various methods such as casting method, extrusion molding method, press molding method, etc. However, since it is lightweight and easy to handle, it is a promising 6 m for wall materials and others.
In producing a plate-shaped artificial marble having a thickness of m or less, there were the following restrictions. That is, the casting method is difficult to manufacture itself, and the extrusion molding method can be manufactured when a thermoplastic resin is used as the molding material, but when a thermosetting resin excellent in heat resistance and weather resistance is used as the molding material. Could not be applied to. On the other hand, in the press molding method, either a thermoplastic resin or a thermosetting resin can be applied as a molding material, the manufacturing process is simple, and the productivity is good, so that the above-mentioned thin plate-like artificial marble It is suitable for production, and in particular, the production of artificial marble by press molding has attracted attention because an artificial marble molding material suitable for press molding of not only unsaturated polyester resin but also acrylic resin has been developed recently. .

However, when a thermosetting artificial marble molding compound is actually press-molded to produce a plate-shaped artificial marble having a thickness of 6 mm or less, 500 × 500.
In the case of a plate-shaped material having a small size of about mm, it can be relatively easily formed into a uniform thickness, but unevenness in thickness occurs as the target material becomes larger, and it is difficult to manufacture an artificial marble having a uniform thickness. In addition, the compound was not sufficiently moved during pressing, and there were problems such as unevenness at some places and seams, which made it difficult to achieve stable production, although it was intended.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for efficiently producing an artificial marble having a thin and uniform thickness when producing an artificial marble by a press molding method using a granular or highly viscoelastic lump compound. The purpose is to provide.

[0006]

According to the present invention, 30-
In a method for producing a large-sized plate-shaped artificial marble molded plate by hot-press molding a granular or high viscoelastic mass thermosetting molding compound containing 80% by weight of an inorganic filler, 1 to 1 near the center rather than the periphery
A method for manufacturing an artificial marble molding plate is provided, which comprises narrowing by 3 mm and performing heat press molding, and further, a metal foil having a thickness of 20 to 60 μm is laminated between the metal molds. This provides a method for manufacturing the artificial marble molding plate, characterized in that the central portion is narrower than the peripheral portion.

That is, in order to manufacture an artificial marble molding plate having a uniform thickness by the thermocompression molding method, it is necessary to adjust it according to the shape and viscosity of the compound used and the size of the object, but at the time of hot press molding. If the space between the upper and lower metal molds is narrowed by 1 to 3 mm in the central part as compared with the peripheral part, the thickness of the artificial marble molded plate obtained after molding becomes uniform,
Further, it has been found that the movement of the compound during the hot press molding is also improved, the biting of air is reduced, and a smooth surface is obtained, and the present invention is achieved.

The thermosetting molding compound used in the present invention is 30 to 80% by weight based on the thermosetting resin.
A granular or highly viscoelastic lump-shaped material containing the above inorganic filler is used. As the thermosetting resin, an acrylic resin, an unsaturated polyester resin, an amino resin, a phenol resin or the like which can undergo a polymerization or condensation reaction can be preferably used. Further, as the filler, aluminum hydroxide,
Calcium carbonate, glass beads, etc. can be appropriately used. Further, in the present invention, a color pigment, a curing agent, a curing accelerator and the like may be appropriately selected and added according to the resin used and the purpose. If the content of the inorganic filler is less than 30% by weight, there is a problem in hardness and heat resistance.
If it exceeds 5% by weight, the movement during hot press molding becomes extremely poor, and a good artificial marble molded plate cannot be produced, which is not preferable.

The manufacturing method of the present invention will be described in detail below. First, the thermosetting molding compound 2 having the above-described composition is supplied to the central portion of the metal mold 4 mounted on the lower heating plate 5 of the pressing machine. At this time, since the molding compound 2 contains a large amount of an inorganic filler, it has a high viscosity and cannot be formed into a uniform sheet as it is. Ordinarily, the molding compound 2 is piled up in a mountain shape. Make sure to put a lump. Next, heating press molding is carried out. At this time, the metal mold 4 on the upper heating plate 5 side and the lower heating plate 5 previously mentioned.
The interval of the upper metal mold 4 is 1 to 3 near the central part rather than the peripheral part.
It is necessary to reduce the width by mm.

Further, it is usually considered necessary to keep the interval between the metal molds 4 as constant as possible when manufacturing a plate-like object having a constant thickness by hot press molding, but the interval is actually constant. 500 x 50 when molded by keeping
There was no problem when the size was about 0 mm, but when the width was 900 x 1800 mm, for example, the thickness of the central part was slightly more than 1.5 times the thickness of the peripheral part, and it cannot be used as a product. Became. Although the reason for this is not clear, it is considered that the molding compound 2 used is a solid having a low fluidity and is molded at a high pressure, and therefore it may be caused by distortion of the hot platen 5 generated during molding.

The adjustment of the distance between the metal molds 4 may be performed by any method, but the thickness adjusting spacer 1 made of a metal foil such as an aluminum foil is formed on the back surface of the upper or lower metal mold. Insert the metal mold 4 when pressurizing
It is preferable to adjust it so that it deforms in order to make the surface of the forming plate smooth, and stack the metal foils to be used in a pyramid shape and sequentially increase the height of the central part to 1 to 3 mm. Metal mold 4 when 1 is created and used
It is particularly preferable that the distance between the two becomes gradually narrower toward the central portion and a molded plate having a more uniform thickness can be manufactured. As the metal foil, it is preferable to use one having a thickness of about 20 to 60 μm. When a metal foil with a thickness of less than 20 μm is used, the number of sheets required for stacking increases, so that an air layer is easily formed between the stacks, the thermal conductivity decreases, the amount of heat used during pressing increases, and energy loss occurs. And the adverse effect on heat curing, and because it is difficult to uniformly transmit heat, whitening or the like occurs on the surface of the molded plate, which is not preferable. Also, 6
When a metal foil having a thickness of more than 0 μm is used, a step due to the lamination of the metal foil appears on the surface of the artificial marble molded plate even if the metal mold 4 is interposed, which is not preferable.

The press molding conditions differ depending on the type of thermosetting resin, but the pressure is 30 to 100 kg / cm ² , and the temperature is 9
The pressing time at 0 to 150 ° C. is 2 to 10 minutes, and according to the method of the present invention, a large-sized artificial marble molding plate having a uniform thickness can be molded even at a low pressure of 30 to 50 kg / cm ² , which is one of the features. Is. In that case, since a press machine for low-pressure molding is sufficient, the cost is low and it is economically advantageous. During hot press molding, the molding compound 2 first comes into contact with the center of the metal mold 4 and moves from the center due to heat and pressure, and evenly spreads to have the same weight per area and is polymerized and cured. The artificial marble molded plate of the invention is obtained. During this time,
Since the air in the mold is naturally degassed, as a result, the artificial marble molding plate having excellent surface properties can be molded without the air being caught in the molding compound 2.

The method of the present invention is particularly suitable for manufacturing a large-sized and thin artificial marble molded plate. Specifically, the obtained artificial marble molded plate has a thickness of 6 mm or less and a width of 600 to 600 mm. 1,250 mm, length 1,500-4,0
It means about 100 mm. Even when the thickness exceeds 6 mm, particularly 10 mm, the accuracy of the thickness can be further improved by applying the method of the present invention, but the necessity becomes smaller than that in the case of a thin product. Similarly, as the size increases, the thickness of the central portion tends to be thicker than that of the peripheral portion. Therefore, it is preferable to perform molding by the method of the present invention.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples. Example Forty-five aluminum foils each having a thickness of 50 μm were laminated at equal intervals in a pyramid shape and attached to the back surface of the upper metal mold, and the central portion was adjusted to be 2.25 mm narrower than the peripheral portion. Next, granular heat curing of a composition of 58% by weight of aluminum hydroxide, 42% by weight of methacrylic resin (30% by weight of prepolymer, 65% by weight of methyl methacrylate monomer, 2% by weight of curing agent, 3% by weight of other coloring agents) A compound for plastic molding to the entire area of the lower metal mold,
Formed to 32% per area, 50 kg
/ cm ² , press at 130 ℃ for 10 minutes, nominal thickness 3mm,
An artificial marble molding plate of the present invention having a size of 900 × 1800 mm was obtained. The molding compound was completely filled in every corner of the metal mold, and the thickness distribution was 3.1 at the maximum.
It was 5 mm and the minimum was 2.82 mm. No whitening or the like was observed on the surface.

COMPARATIVE EXAMPLE Using the molding compound of the above-mentioned example, pressing was performed under the same conditions as in the example without narrowing the central portion, and the nominal thickness was 3 m.
Although an artificial marble molding plate having a size of 900 × 1800 mm was obtained, the molding compound was not filled in the end of the metal mold, and the thickness distribution was 3.62 m at the maximum.
m was 2.28 mm at the minimum portion, which caused a large variation with respect to the nominal thickness. In addition, there was a whitened part on the surface, which was thought to be air entrapped.

[0016]

Industrial Applicability According to the present invention, a large-sized artificial marble molding plate having a uniform thickness can be manufactured by a hot press molding method in a short time and with a simple operation. It has become possible.

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating a method of the present invention.

[Explanation of symbols]

 1 Spacer 2 Thermosetting molding compound 3 Seal part 4 Metal mold 5 Press machine hot platen

Claims (2)

[Claims] 1. A method for producing a large-sized plate-shaped artificial marble molded plate by hot press molding a granular or highly viscoelastic blocky thermosetting molding compound containing 30 to 80% by weight of an inorganic filler. In the method of manufacturing an artificial marble molding plate, the metal molds are heated and press-molded with the interval between the metal molds narrowed by 1 to 3 mm in the vicinity of the central portion from the peripheral portion. 2. The space between the metal molds has a thickness of 20.
The method for producing an artificial marble molding plate according to claim 1, wherein the central portion is made narrower than the peripheral portion by interposing a laminated metal foil having a thickness of -60 μm.