JPS6158851A - 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 produces artificial marble with a two-layer structure that has excellent wear resistance by using a filler with a fine average particle size and a filler with a coarse particle size. The present invention relates to a manufacturing method that can be obtained.

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).

(Prior art) Conventional methods for manufacturing oak artificial marble include using resin concrete, and ways to increase 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, a filler, and an additive to a prepolymer, thoroughly kneading the mixture, and then vacuuming.

In this case, the particle size of the filling material is several μI11 to 0.5
It is quite large, like a crane. 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 and 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 as a method to improve abrasion resistance, after pre-coating the plastic surface as necessary, organosilane-based, polyfunctional acrylic-based A hard coating agent such as the following is diluted with a solvent and applied.

Then, this is dried to remove the solvent, and then cured by heat treatment, ultraviolet irradiation, or the like.

Furthermore, when a gel coat layer is formed, it is done 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 uses a resin layer (not containing glass fiber) on the surface of the mold.
Fillers are added), wait for gelation, 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.

[Problem that the invention seeks to solve]

However, in the case of the conventional resin concrete, an inorganic powder having a relatively coarse particle size of several μm to 0.5 fi is used as a filler. Therefore, there was a drawback that the adhesion between the cured resin and the filler was weak (and the filler formed into layers 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 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. Another disadvantage was that the equipment required for this purpose was large-scale. In addition, due to the properties of the hard coating agent, the PAr! L is limited, and only extremely thin products of 3 to 8 micrometers can be obtained, which has the disadvantage of lacking 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, a predetermined faN is performed after gelling the gel coat layer, making the molding process complicated. In particular, in the case of cast products, it is difficult to apply a gel coat layer in one molding process, and peeling is likely to occur due to poor adhesion to the base material.

In addition, with conventional artificial marble such as resin concrete, the motif that appears on the surface is only a single layer pattern, and it cannot be said that it has the excellent aesthetics that would attract demand. .

In short, conventional artificial marble has problems that need to be solved in terms of quality such as wear resistance, workability in production, and aesthetics.

[Means for solving problems]

The present invention improves and eliminates the above drawbacks of the conventional technology by adding a polymerization initiator to a resin material base material such as an acrylic prepolymer, and adding calcium carbonate, aluminum hydroxide, silicate compounds, etc. A fine filler with an average particle size of 2 μm or less and a filler with an average particle size of 10 μm.
Add the above two types of coarse fillers, add additives such as a crosslinking agent, mold release agent 1 reaction accelerator, and filler as necessary, stir and mix, and degas the mixture to form a slurry. The slurry-like composition is poured into a mold and the above-mentioned 2.
Production of artificial marble characterized in that the seed filler is precipitated in the form of 2Fi, and then the slurry-like composition is heated and cured to obtain an artificial marble with a two-layer structure having excellent wear resistance. The purpose is to provide a method.

The characteristics of each material of the artificial marble of the present invention will be explained below with reference to the drawings.

The base material 1 made of resin material such as acrylic prepolymer has a thickness of 50 to
It is desirable to have a viscosity of 300 cp, because if it is less than 50 cp, the fine filler 2 described below will settle, making it impossible to improve the wear resistance of the surface layer. Moreover, if it is 3 oocp or more, it is difficult to add a large amount of filler, and the wear resistance of the surface layer cannot be improved. Other materials such as unsaturated polyester can also be used.

Of course, the base material 1 as a resin material is transparent.

As the polymerization initiator, radical polymerization initiators such as organic peroxides such as BPO are suitable. The amount of the polymerization initiator is suitably in the range of 0.01 to 1.0% based on the base material 1 as a resin material. The reason for this is that polymerization may not occur at 0.01 wt% or less, and even if it does polymerize, it takes a long time.

This is because if the amount is 1.0 ML% or more, there is a risk that the resin material as the base material 1 will foam due to heat generation during polymerization.

Calcium carbonate, aluminum hydroxide, silicate compounds (
Fillers such as magnesium silicate, calcium silicate, aluminum silicate) with fine particle sizes of 2 μm or less,
The reason why two types of coarse grains having a particle size of 10 μm or more are used is as follows. That is, one of them is
By making the fine filler 2 with a slow sedimentation rate exist in the surface layer of the product (artificial marble), it is difficult for the filler to peel off.
This is to improve wear resistance. One of the other reasons is that these fillers are present in the resin material as the base material 1 and have different sedimentation speeds, so we focused on this and used the difference in sedimentation speeds to separate the fillers into 2 fillers. Eyebrow-like and pear-shaped,
This is to improve the aesthetics of the pattern appearing on the surface.

Incidentally, the above-mentioned filler consisting of the fine filler 2 and the coarse filler 3 can have a difference in sedimentation speed by changing their specific gravity, and it is possible to have a 2Jfi structure. However, we can calculate the sedimentation rate using the following equation (1).
As is clear from Stokes' Law J, the main factor that affects the sedimentation rate is the particle size, and the reason for the technical limitation of the present invention is obvious.

In other words, Stokes' law is: 18μ However, ■: Sedimentation velocity μ: Resin viscosity g: Gravitational acceleration ρS Density of two particles (specific gravity) ρ: Liquid density (resin specific gravity) d: Particle size, The effect on the sedimentation velocity V is that the particle diameter d is 2.
This is clear from the fact that it is the largest multiplication factor.

Therefore, in order to form a 2Jiii structure of the filler in the resin material as the base material 1 by utilizing the difference in sedimentation speed, it is sufficient to control the particle size of the particles.

It goes without saying that what is most preferable is to control the particle size of the particles and comprehensively determine the specific gravity of the particles, the viscosity of the resin material, etc. Therefore, in the examples described later, the specific gravity of the filler 2 of fine particles is made small, and the specific gravity of the filler 3 of coarse particles is made thick (to obtain a product. The time required for settling of the filler to form a two-layered structure can be shortened, and workability can be improved.

For reference, the moving path ff1H of the filler particles is 18μ, where t: time (standing time). Therefore, it is clear from the above equation (2) that:
This means that as the standing time and the settling velocity V increase, the moving path [H] of the filler becomes larger. However, if the value of the standing time t is increased, there is a problem in terms of work efficiency, which is not preferable.
The duration may be between 1 and 10 hours, and 1 to 10 hours is practical. In the examples described later, taking these things into consideration, the specific gravity of the fine filler 2 is decreased to decrease the sedimentation velocity (2), and the specific gravity of the coarse filler 3 is increased to increase the sedimentation rate V. By doing so, we are able to shorten the standing time and make manufacturing work more efficient.

Therefore, the amount of the filler consisting of the above-mentioned fine filler 2 and coarse filler 3 is suitably in the range of 30 to 70 wt%. The reason for this is that if it is less than 30%, the strength of the resin material will not be increased sufficiently, and if it is more than 70%, the amount of filler will be too large, resulting in poor moldability, and the physical properties will deteriorate. This is because it causes deterioration (bending and wear resistance).

The manufacturing order is such that a polymerization initiator is added to a base material 1 of a resin material such as an acrylic prepolymer, and after this is dissolved, a fine filler 2 and a coarse filler 3 are added. Then, additives such as a crosslinking agent, a mold release agent 1 reaction accelerator, and an R material are added as necessary and mixed in a mixer, etc., and the mixture is further vacuum degassed to obtain a slurry composition. , pouring the slurry composition into a conventional casting mold such as a glass mold, FRP mold, or metal mold;
The fine filler 2 and the coarse filler 3 are left to stand still to form a two-dimensional shape, and then heated and hardened.

The heating conditions are such that the heating temperature is in the range of room temperature to 80°C.

This heating may be performed simultaneously during the standing time.
That is, the fine filler 2 and the coarse filler 3 may be separated into layers until the resin material is completely cured by heating, and a heating time of 0.5 to 30 hours is sufficient. be.

This results in a two-layer artificial marble structure with excellent wear resistance.
It is possible to obtain

By making the refractive index of the fine filler 2 close to the refractive index of the resin material as the base material 1, light from the surface hits the coarse filler 3 in the lower layer and is diffusely reflected, as shown by the arrow in the drawing. It is possible to obtain a product with deep transparency and high quality texture.

Further, additives such as a crosslinking agent, a mold release agent 1 reaction accelerator, and a tI agent may be added in appropriate amounts depending on the initial properties during manufacturing and the required performance of the product.

〔Example〕

Next, a specific example will be described. First, the viscosity is 150c
BPO as a polymerization initiator was added to 40Ht% of the acrylic prepolymer of p to 0.05Ht% of the acrylic prepolymer.
Add t% and dissolve. As a fine filler, the average particle size is 0.2μ, the specific gravity is 2.0g/aj, and the refractive index is 1.4.
9. 20wt% of magnesium silicate was added as a coarse filler with an average particle size of 60μm and a specific gravity of 2.7g/cj.

Add 40-t% of calcium carbonate with a refractive index of 1.66 and mix with a mixer.Next, the mixture is vacuum degassed to obtain a slurry composition, which is poured into a glass mold and heated at 60°C for 7 hours. By doing this, the sedimentation rate difference between magnesium silicate as a fine filler and calcium carbonate as a coarse filler was used to separate them into layers, and the resin was cured. As a result, an artificial marble with a 2N structure as shown in the drawing is obtained, in which magnesium silicate as a fine filler is uniformly scattered throughout the base material, and calcium carbonate as a coarse filler is precipitated and exists only in the lower layer. Ta. The size of this example product is 100 aaXloQ cIIX
1 cll.

Regarding the abrasion resistance of this example product, artificial marble was manufactured using a conventional method, and a taper abrasion test (JIS K69
02) for comparison. In the production of artificial marble by the conventional method, the average particle size is 17 μn + 1ffl refractive index is 1.5.
7. Use a single filler with a specific gravity of 2.4 g/cd
The other conditions are the same as in the embodiments according to the present invention described above. According to this, the product of this example was 0.040 g/100 times, while the conventional product was 0.107 g/100 times.

The reason why the product of this example has excellent wear resistance is that the particle size of the filler (magnesium silicate) present in the surface layer is small, so its specific surface area is large (and the resin as a base material). This is because the reinforcing effect is fully exhibited due to the increased adhesion to the material and the high filled term density.

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, as fillers added to resin materials such as acrylic prepolymers, fine fillers with an average particle size of 2 μm or less and coarse fillers with an average particle size of 10 μm or more are used. By using the difference in sedimentation speed between the two types of fillers, the filler can be made into two layers,
It is possible to obtain artificial marble with excellent aesthetics. Furthermore, since the surface layer contains fine fillers, its specific surface area is large, and a product with excellent adhesion to the resin material as a base 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 is a longitudinal cross-sectional view of the artificial marble according to the present invention.

Claims (1)

[Claims] 1. A polymerization initiator is added to the base material of a resin material such as an acrylic prepolymer, and a fine filler such as calcium carbonate, aluminum hydroxide, or a silicate compound with an average particle size of 2 μm or less is added. Two types of coarse fillers with an average particle size of 10 μm or more are added, and if necessary, additives such as a crosslinking agent, a mold release agent, a reaction accelerator, and a pigment are added, mixed with stirring, and the mixture is removed. The slurry composition is poured into a mold to precipitate the two types of fillers in two layers, and then the slurry composition is heated and cured to provide wear resistance. A method for producing artificial marble characterized by obtaining artificial marble with an excellent two-layer structure.