JPS6144747A - Manufacture of artificial marble - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a manufacturing method that makes it possible to obtain artificial marble with excellent wear resistance by using a filler with a small particle size.

Note that the term "artificial marble" as used herein refers to an artificial product that has an appearance and use similar to natural marble (the same applies hereinafter).

[Conventional technology]

Conventionally, methods for manufacturing this type of artificial marble include using resin concrete, and methods for increasing wear resistance include using hard coating and forming a gel coat layer.

In the case of resin concrete, a slurry-like mixture is usually obtained by adding a polymerization initiator, filler, and additives to a prepolymer, thoroughly kneading the mixture, and vacuum degassing.

In this case, the particle size of the filler is quite large, ranging from several μm to 0.5 μm. Then, the slurry mixture is poured into a mold, left to stand at room temperature or cured by heating above room temperature, and subjected to cutting, bending by heating, lamination 9 surface finishing, etc., to create a countertop for a kitchen or bathroom. It is used for products such as tables, interior and exterior materials, and bathtubs.

In the case of hard coating, after pre-coating the plastic surface as necessary, organosilane-based,
A hard coating agent such as polyfunctional acrylic is diluted with a solvent and applied. This is then dried to remove the solvent, and cured by heat treatment, ultraviolet irradiation, or the like.

The gel coat layer is applied for the purpose of aesthetics and protection of resin concrete or FRP molded products, and for example, isophthalic acid-based polyester resins are used. The molding method is to form a resin N that does not contain glass fibers (filler is added) on the surface of a mold, wait for it to gel, and then perform predetermined lamination to produce a product. Products formed with this gel coat layer have excellent water resistance, chemical resistance, and mechanical strength.

(Problems to be Solved by the Invention) However, in the case of the conventional resin concrete, an inorganic powder with a relatively coarse particle size of several microns to 0.5 va is used as a filler. There is a drawback that the adhesiveness between the cured resin and the filler is weak, and the filler comes off due to scratching, abrasion, etc.

Therefore, the current situation is to further form a hard coat, gel coat layer, etc. on the surface of resin concrete.
This made the process complicated and also caused an increase in costs.

Further, in the case of a hard coat, there is a drawback that there are many processing steps. Moreover, after applying the hard coat agent to the plastic surface, the temperature and humidity must be adjusted using air conditioning equipment to prevent the occurrence of cranks, etc., and the solvent must be gradually removed, making temperature and humidity control troublesome. be. Moreover, the equipment for this purpose also had the disadvantage of being a major loss. In addition, the film thickness of the hard coating agent is limited due to the characteristics of the hard coating agent, and only an extremely thin layer of 3 to 8 .mu.m can be obtained, resulting in insufficient hardness and strength. Furthermore, the adhesive force between the plastic material as the base material and the hard coating agent is insufficient unless the combination is limited, and there is a drawback that peeling is likely to occur.

Furthermore, when forming a gel coat layer, predetermined lamination is performed after the gel coat layer is gelled, and the molding process is complicated. In particular, in the case of cast products, it is difficult to apply a gel coat layer in one molding process, and there are also disadvantages in that peeling is likely to occur due to poor adhesion to the base material.

[Means for solving problems]

In view of the above-mentioned drawbacks of the conventional technology, the present invention has been made to improve and eliminate the above drawbacks. 30 to 70% of fillers such as calcium carbonate, aluminum hydroxide, silicate compounds, etc. with a particle size of 1.0 μm or less are added, and if necessary, additives such as a crosslinking agent, a mold release agent, a reaction accelerator, and a pigment are added. is added and mixed with stirring, the mixture is deaerated to form a slurry composition, and the slurry composition is poured into a mold and heated to harden to obtain artificial marble with excellent wear resistance. The present invention aims to provide a method for producing artificial marble characterized by the following.

The base material of resin material such as acrylic prepolymer is 50 to 3
It is desirable to have a viscosity of 0.00 cp. The reason is,
This is because if it is less than 50 cp, fine fillers described below will settle, making it impossible to improve the wear resistance of the surface layer. Moreover, if it is 300 cp or more, it is difficult to add a large amount of filler, and the wear resistance of the surface layer cannot be improved. the material is,
Other materials such as unsaturated polyester can also be used.

As the polymerization initiator, radical polymerization initiators such as organic peroxides such as BPO are suitable. The polymerization initiator is 0.01
~1. The reason why the range of 0.01 wt% is set is that polymerization may not occur if the amount is less than 0.01 wt%, and even if it does polymerize, it will take a long time. This is because if the content exceeds 1.0111 t%, there is a risk that the resin material will foam due to heat generated during polymerization.

Also, calcium carbonate and aluminum hydroxide.

The reason why the particle size of fillers such as silicate compounds (magnesium silicate, calcium silicate) is set to 1.0μ steel or less is that
If it is .mu.m or more, the filler present on the surface of the product (artificial marble) is likely to peel off (and it lacks wear resistance).

The reason why the filling amount of the filler was limited to the range of 30 to 7011 t% is that if it is less than 30 wt%, the strength of the resin material cannot be increased sufficiently, and if it is more than 70-t%, the filler This is because if the amount is too large, the moldability deteriorates, and the physical properties (bending and abrasion resistance) actually deteriorate.

The manufacturing process involves adding a polymerization initiator to a base material of a resin material such as an acrylic prepolymer, and then adding a filler after dissolving the polymerization initiator. Then, if necessary, additives such as a crosslinking agent, a release agent, a reaction accelerator, and a material are added and mixed using a mixer, and the mixture is further degassed under vacuum to obtain a slurry composition. Next, the slurry composition is poured into a conventional casting mold such as a glass mold, an FRP mold, or a metal mold, and is heated and cured. The heating conditions are such that the heating temperature ranges from room temperature to 80°C, and the heating time ranges from 0°C to 30 hours.

Thereby, it is possible to obtain artificial marble with excellent wear resistance.

Note that by bringing the refractive index of the filler closer to that of the resin, it is possible to obtain a product with transparency and high-quality texture. Further, additives such as a crosslinking agent, a mold release agent, a reaction accelerator, and a pigment may be added in appropriate amounts depending on the initial characteristics during manufacturing, the required performance of the product, and the like.

〔Example〕

Table 1 shown below shows the results of comparing the abrasion resistance and transparency of artificial marble produced by the production method according to the present invention and the conventional production method. Abrasion resistance is the result of a taper abrasion test (JIS K6902), and the unit is g/
100 times. Transparency indicates the transmittance of white light when the sample thickness is 0.4 mm.

(Margins below, continued on next page) The drawings are trial number 1 in Table-1. 2. 7 shows the relationship between the average particle size and wear resistance of filler No. 7.

What is clear from this drawing and the results in Table 1 is that the wear resistance characteristic curve changes rapidly when the average particle size of the filler is approximately 1.0 μm. Therefore, the average particle size of the filler may be 1.0 μm or less. The average particle size of the preferable filler is 0.6μ as shown in Fragrances 3 to 6 in Table 1.
m or less.

When the average particle size is 0.6 μm or less, the wear resistance shows very excellent values. This is because the particle size of the filler is small, so its specific surface area is large, which increases its adhesion to the resin material as a base material, and the high packing density provides a sufficient reinforcing effect. It is.

It should be noted that the present invention is not limited to the above-mentioned embodiments,
For example, another filler is calcium carbonate.

Silicate compounds, inorganic oxides such as silica, etc. are possible.

Furthermore, it is considered that unsaturated polyester or the like can be used as the resin material as the base material.

〔Effect of the invention〕

As explained above, in the present invention, the average particle size of the filler added to the resin material such as acrylic prepolymer is set to 1.
Since it is set to 0 μm or less, the specific surface area of the filler becomes large, and an excellent adhesive force between the filler and the resin material can be obtained. As a result, the surface of the product (artificial marble) has excellent wear resistance.

[Brief explanation of the drawing]

The drawing shows the relationship between the average particle size of the filler and the wear resistance of the product (artificial marble).

Claims (1)

[Claims] 1. Add 0.01 to 1.0 wt% of a polymerization initiator to the base material of a resin material such as acrylic prepolymer, and add calcium carbonate, aluminum hydroxide, silicate compounds, etc. with an average particle size of 1.0 μm or less. Add 30 to 70 wt% of filler, further add additives such as a crosslinking agent, a mold release agent, a reaction accelerator, and a pigment as necessary, stir and mix, and degas the mixture to obtain a slurry composition, A method for producing artificial marble, characterized in that artificial marble with excellent wear resistance is obtained by pouring the slurry composition into a mold and heating and curing it.