JPH0733500A - Marble like article improved in strength and production thereof - Google Patents

Abstract

PURPOSE:To improve strength with stereoscopic effect and transparent texture at a low cost by distributing irregularly and incorporating large sized transparent chip particles soluble in methyl methacrylate in a prescribed matrix. CONSTITUTION:A composition for matrix is obtained by blending 20-80 pts.wt. polymer syrup composed mainly of methyl methacrylate and 300-2000cp in viscosity, 80-20 pts.wt. inorganic powder such as aluminum hydroxide and, if necessary, a coloring agent such as red color. The other hand, the transparent chip particles 0.1-20% in rate of dimensional change when the particle is completely dipped into methyl methacrylate (23 deg.C+ or -2 deg.C, for one day) and <=10mm in maximum dimension is obtained by molding polystyrene or the like. And a marble like article is produced by filling a irregularly dispersed mixture obtained by mixing 0.1-50 pts.wt. particles with 100 pts.wt. matrix into a mold and polymerizing and molding in the presence of the radical initiator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marble-like article having improved strength and a method for producing the same, and more particularly, a large-sized transparent chip dispersed in a matrix of a methyl methacrylate polymer-inorganic powder. The present invention relates to a marble-like article which is made of particles, has a rich three-dimensional effect, has a deep transparent texture, and has improved strength, and a method for producing the same.

[0002]

2. Description of the Related Art Artificial marble mainly composed of methyl methacrylate is widely used as a wall material, a kitchen counter, etc. by utilizing its excellent weather resistance and physical properties.

For example, Japanese Patent Publication No. 61-24357 (JP-A No. 52-952) discloses a matrix composed of a polymer such as polymethylmethacrylate and a filler such as aluminum hydroxide, and 200 μm or more. Imitation granite articles comprising opaque, translucent and / or transparent particles of

Japanese Patent Application Laid-Open No. 3-2814 related to the applicant's proposal
No. 8 discloses a transparent or translucent matrix composed of a methyl methacrylate resin and aluminum hydroxide,
As an opaque particle, an artificial stone is described in which a combination of a plurality of kinds of fine particles and coarse particles and having different color tones is mixed.

[0005]

However, the currently marketed artificial marble mainly composed of methyl methacrylate has a physical property superior to that of natural stone and is an easy-to-handle article. As for the handle, the one that is very similar to natural stone has not been obtained yet.

[0006] On the other hand, on the other hand, solidified and molded articles made from crushed natural stones have been put on the market and used, but in the artificial marble mainly composed of methyl methacrylate,
Mixing a large amount of crushed natural stones weakens the intermolecular bond between methyl methacrylate and natural stones, resulting in weak strength, or conversely trying to obtain a strong article. However, there are drawbacks such as the need for a large-scale molding machine.

The inventor of the present invention blends a large matrix of transparent chip particles into a base matrix prepared by adding an inorganic powder to a polymer mainly composed of methyl methacrylate to give a three-dimensional effect and a deep transparent feeling. It was found that a certain artificial marble can be obtained, and by using transparent chip particles having solubility in methyl methacrylate, it is possible to obtain a marble-like article having large particles and high strength.

[0008] That is, an object of the present invention is to provide an inexpensive marble-like article having a remarkably improved strength while having a transparent texture with a rich three-dimensional effect and depth.

[0009]

According to the present invention, a matrix containing 20 to 80 parts by weight of a polymer mainly composed of methyl methacrylate and 80 to 20 parts by weight of an inorganic powder has a maximum dimension of 10 mm or less. Also provided is a marble-like article characterized by containing 0.1 to 50 parts by weight of large-sized transparent chip particles having solubility in methyl methacrylate in an irregularly distributed state.

According to the present invention, a matrix composition containing 20 to 80 parts by weight of a polymer syrup mainly composed of methyl methacrylate and 80 to 20 parts by weight of an inorganic powder,
0.1 to 50 parts by weight of large transparent chip particles having a maximum dimension of 10 mm or less and having solubility in methyl methacrylate are mixed and dispersed in an irregularly distributed state, and this mixture is radicalized in a mold. There is provided a method for producing a marble-like article, which comprises polymerizing and molding in the presence of an initiator.

The transparent chip particles used in the present invention are obtained when the particles are completely immersed in methyl methacrylate (23
It is preferable that the particles have a dimensional change rate of 0.1 to 20%, particularly 0.4 to 15% at a temperature of ± 2 ° C for 1 day.

[0012]

In the present invention, the matrix composed of the methyl methacrylate polymer and the inorganic powder has a maximum dimension of 10 mm.
It is a remarkable feature that the following is contained and large-sized transparent chip particles having solubility in methyl methacrylate were contained in an irregularly distributed state.

Conventionally, the opaque, translucent and / or transparent particles used in this type of molded article are all insoluble, whereas in the present invention, methyl methacrylate is used as the transparent chip particles. Use one that has solubility. According to the present invention, due to this feature, even when the transparent chip particles are large, the strength of the molded product can be remarkably improved.

See Example 1 and Comparative Example 1 below. If the chip particles are coarsely crushed minerals or those with high solubility, the bending strength of the molded product is 320 to 410 kgf / cm.
^Although it is only on the order of ² , when transparent chip particles having solubility in methyl methacrylate are mixed in the same matrix, the strength of the molded product is 550 to 570 kgf.
This is an unexpected effect according to the present invention, which is improved to the order of / cm ² .

The reason for this is as follows. That is, in the marble article according to the present invention, transparent chip particles are mixed with a matrix composition containing a methyl methacrylate polymer syrup and an inorganic powder, and the mixture is polymerized in a mold in the presence of a radical initiator. Obtained by molding, the transparent chip particles show solubility in methyl methacrylate contained in the polymer syrup, so at the interface between the transparent chip particles and the matrix, a methyl methacrylate polymer chain and a transparent chip are formed. It is recognized that molecular entanglement occurs between the polymer chains of the particles and the bonding at the interface is significantly improved.

In the present invention, it becomes possible to mix chip particles without lowering the strength of the molded body,
Moreover, since the chip particles are transparent, have a large size, and are irregularly distributed, an excellent three-dimensional effect and a transparent texture with a depth can be imparted, and the appearance is very close to that of marble.

In the present invention, the transparent chip particles are obtained by completely immersing the particles in methyl methacrylate (23
The rate of dimensional change (° C ± 2 ° C, 1 day) is preferably within 0.1 to 20%. This dimensional change rate is closely related to the degree of dissolution or swelling of the transparent chip particles in methyl methacrylate, and if it is less than 0.1%, the strength is greatly reduced. On the other hand, if it exceeds 20%, the three-dimensional effect and the transparent feeling due to the incorporation of the transparent chip particles tend to be impaired, and the working efficiency tends to decrease.

[0018]

Preferred Embodiment of the Invention

[Matrix] The matrix in the article of the present invention is a polymer 20 to 80 containing methyl methacrylate as a main component.
And 80 to 20 parts by weight of inorganic powder.

When the content of the polymer in the matrix is less than the above range, the toughness and impact resistance of the article are lower than those in the above range, while when it exceeds the above range, The hardness, dimensional stability, and heat resistance of the article are lower than those in the above range.

The resin used in the present invention is a polymer containing methyl methacrylate (MMA) as a main component, which may be composed of methyl methacrylate alone, or is mainly composed of methyl methacrylate and a small amount thereof. , For example 0.1 to 5 parts by weight of other ethylenically unsaturated compounds,
For example, styrene, vinyl acetate, acrylonitrile, and methacrylic acid, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, methyl acrylate, ethyl acrylate, It may contain a (meth) acrylic acid ester such as butyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate.

This polymer is used in the form of syrup in the production of articles and is a so-called partially polymerized syrup,
To have the proper combination of castability and polymerization curability,
300-2,000cp (centipoise), especially 500-600c
Prepolymerized to have p-viscosity.

The inorganic powder used in the matrix may be any of the inorganic fillers commonly used in molded articles of this type. Suitable examples thereof are dry process or wet process amorphous silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, aluminum silicate, calcium silicate, clay, talc, kaolin, barium sulfate, calcium sulfate and the like.

Of these, aluminum hydroxide is preferred. As the aluminum hydroxide, various aluminum hydroxides are used, but alumina trihydrate, that is, gibbsite is particularly preferably used. Since it has a refractive index close to that of the methyl methacrylate polymer, excellent transparency or translucency is obtained, and as a hydrate property, it is also excellent in imparting flame retardancy to a molded product.

In addition to the above essential components, the matrix used in the present invention may contain additives such as colorants and monomers. Further, a polymerization initiator such as an organic peroxide can be added to the syrup composition for forming a matrix.

The colorant includes dyes, organic pigments, inorganic pigments, and the like, and specifically, red (para red, lysole red, alizarin lake, thioindigo maroon, red iron oxide, molybdenum red); orange (permanent orange, persia orange) , Induslen Orange 6-R); Yellow (Hansa Yellow G, Quinoline Yellow Lake, Yellow Lead,
Zinc yellow, titanium yellow); green (naphthol green, green gold); blue (phthalocyanine blue, Victoria blue lake, ultramarine blue, cobalt blue); black (carbon black, iron black); white (zinc white, lead white, titanium white) Rutile); purple (first violet BL, methyl violet lake); and the like. These colorants are methyl methacrylate-based polymers 10
It is desirable that the amount is 0.1 to 5 parts by weight, especially 0.3 to 3 parts by weight, based on 0 parts by weight.

As the monomer to be added to the polymer syrup, all of the monomers described above for the polymer syrup can be used. In addition, a polyfunctional ethylenically unsaturated monomer can be used as a modifying monomer. For example, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate, diethylene glycol bisallyl carbonate, etc. may also be used.

Radical initiators for polymerizing and curing the polymer syrup include lauryl peroxide, acetyl peroxide, benzoyl peroxide and t-.
Butyl peroxypivalate, t-butyl peroxy neodecanoate, t-butyl peroxy octoate,
Organic peroxides such as diisopropyl peroxydicarbonate and azo compounds such as bisazoisobutyronitrile are used alone or in combination of two or more kinds, and the amount thereof is 0.1 to 5 parts by weight per 100 parts by weight of the polymer syrup. , Especially 0.
3 to 3 parts by weight.

[Transparent Chip Particles] The transparent chip particles used in the present invention are large particles having a maximum dimension of 10 mm or less and having solubility in methyl methacrylate. Examples of the resin forming the transparent chip particles include methyl methacrylate (MMA) -based resin, polystyrene, ethyl polyacrylate, polyvinyl acetate, polyvinyl chloride,
Among polyester, polyvinyl alcohol, epoxy resin, etc., the dimensional change rate by the above-mentioned measurement method is 0.1 to 20.
%, Preferably 0.4 to 15% is used. These resins may be partially crosslinked with a polyfunctional monomer under the condition that the dimensional change rate is within the above range.

The transparent chip particles have a thickness of 1.25 mm.
1.0% or more, especially 1.5%
It is preferable to show the above visible light transmittance T (T = It / Ii × 100, where Ii is the incident light intensity and It is the transmitted light intensity). The transparent resin chip may contain the above-mentioned inorganic powder, colorant, etc. within the range of exhibiting the above-mentioned transparency. For example, it should be understood that the transparent chip particles may be a mixture of resin particles having different hues or saturations.

The transparent chip particles used in the present invention are large particles, and the particle size thereof is generally in the range of 1 to 10 mm.
However, inclusion of coarse particles larger than 10 mm should be avoided. The chip particles may have a wide particle size distribution over the above particle size range, or may have a relatively sharp particle size distribution within the above particle size range.
In order to make the distribution irregular in the matrix, it is preferable to have the former wide distribution.

The particle shape of the chip particles is not particularly limited. For example, the particles may be irregular particles obtained by pulverizing a molded product, or regular particles produced by a granulation method, for example, spherical particles, glazed particles, prisms, and circles. It may have a columnar shape, a tablet shape, a plate shape, a flake shape, or the like.

Any method may be used to produce the transparent chip particles. For example, in the case of a preformed resin, this is press-molded or extruded, and if necessary, it is cut, cut or crushed to obtain a predetermined granular material. Also, using polymer syrup, monomer,
After subjecting this to bulk polymerization, suspension polymerization, etc. by a radical initiation means such as organic peroxide, heat, ultraviolet rays, etc., if necessary, crushing etc. are carried out to obtain a predetermined granular material. The particle size is controlled by classification. In order to enhance the pulverization efficiency of the resin, it is effective to pulverize at a low temperature or to contain an inorganic substance in the resin.

The transparent chip particles may be blended in the polymer syrup as they are, but may be surface-treated with a silane coupling agent or the like to improve the wettability, if desired. it can. As such a silane coupling agent, aminopropyltriethoxysilane, vinyltriethoxysilane, etc. are used. The treating amount of the coupling agent may be as small as 0.1 to 2%.

[Composition and Production] According to the present invention, the transparent chip particles are mixed with a matrix composition containing a polymer syrup containing methyl methacrylate as a main component and an inorganic powder, and the particles are randomly distributed. The resulting mixture is polymerized and molded in a mold in the presence of a radical initiator.

The transparent chip particles are preferably used in an amount of 0.1 to 50 parts by weight, particularly 5 to 30 parts by weight, based on the matrix. When the blending amount of the transparent chip particles is smaller or larger than the above range, the texture of the article, the appearance characteristics, particularly the deep three-dimensional effect are deteriorated. Further, if the content of the transparent chip particles is more than the above range, the castability into a mold tends to deteriorate, and the strength of the molded body tends to decrease.

The mixture of the matrix composition and the transparent chip particles should be kept within a range in which the surface of the transparent chip particles is uniformly wetted by the matrix composition. It should be avoided as it interferes with the irregular distribution of particles. In order to form an irregular distribution state, it is preferable that a structure of transparent chip particles is formed in the mixture, and that the structure has a wide particle size distribution of transparent chip particles and the transparent chip particles have an irregular shape. And excessive mixing destroys this structure.

This mixture is placed in a mold and polymerized in the presence of a radical initiator. The polymerization conditions are not particularly limited, but generally a temperature of 60 to 110 ° C. and a range of 1 to 5 hours are suitable.

The obtained molded product can be used as it is, or after polishing the surface, for various interior and exterior building materials, bathtubs, wash tubs, various tables and the like.

[0039]

The present invention will be further described in the following examples. Example 1 Acrylic resin pellets having an average molecular weight of about 200,000 (particle diameter φ
2 × 3 mm) is finely pulverized with an atomizer (manufactured by Fuji Paudal Co., Ltd., screen diameter φ1) to obtain a particle size of 0.5 to 1.5 m.
m transparent particles were obtained. Next, to 10 parts by weight of these transparent particles, 30 parts by weight of methyl methacrylate syrup, 60 parts by weight of aluminum hydroxide (average particle size 15 μm), 0.3 part by weight of benzoyl peroxide, 0.3 part by weight of trimethylolpropane trimethacrylate. After mixing, mixing and defoaming under reduced pressure, and injecting into a mold of 300 × 300 × 12 mm,
It was heat-cured in an oven at 0 ° C. for 2 hours and 100 ° C. for 1 hour. The obtained cured product was an article resembling natural stone in which transparent particles were randomly distributed. As shown in Table 1,
The transparent chips were soluble in methyl methacrylate and were excellent in mechanical strength.

Example 2 100 parts by weight of polyester resin was mixed with 1 part by weight of benzoyl peroxide, and a cured product was obtained in the same manner as in Example 1. As shown in Table 1, this cured product was an article having excellent overall texture and strength.

Comparative Example 1 A cured product was obtained from acrylic resin pellets having an average molecular weight of 60,000 by the same method as in Example 1. In producing this cured product, as shown in Table 1, the increase in viscosity was large during the molding process, which was extremely inconvenient and inferior in strength.

Comparative Example 2 A cured product of natural granite was obtained in the same manner as in Example 1.
As shown in Table 1, this cured product was very similar in appearance to natural marble, but was inferior in strength.

[0043]

[Table 1]

[0044]

According to the present invention, a large transparent chip particle having a maximum dimension of 10 mm or less and having solubility in methyl methacrylate is not contained in a matrix composed of a methyl methacrylate polymer and an inorganic powder. By including the particles in a regularly distributed state, the bond at the interface between the transparent chip particles and the matrix is significantly improved, and as a result, the strength of the molded product is improved even when the transparent chip particles are large particles. It can be significantly improved.

In the present invention, chip particles can be blended without lowering the strength of the molded body,
Moreover, since the chip particles are transparent, have a large size, and are irregularly distributed, an excellent three-dimensional effect and a transparent texture with a depth can be imparted, and the appearance is very close to that of marble.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // C04B 111: 54

Claims (4)

[Claims] 1. Large particles having a maximum size of 10 mm or less and having solubility in methyl methacrylate in a matrix containing 20 to 80 parts by weight of a polymer mainly containing methyl methacrylate and 80 to 20 parts by weight of inorganic powder. The marble-like article, characterized in that it contains 0.1 to 50 parts by weight of the transparent chip particles of 1. in an irregularly distributed state. 2. The transparent chip particles, when the particles are completely immersed in methyl methacrylate (23 ° C. ± 2 ° C.,
The article according to claim 1, which is a particle having a dimensional change rate of 0.1 to 20% within 1 day. 3. A matrix composition containing 20 to 80 parts by weight of a polymer syrup mainly composed of methyl methacrylate and 80 to 20 parts by weight of an inorganic powder, and having a maximum dimension of 10 mm.
0.1 to 50 parts by weight of large transparent chip particles having the following properties and solubility in methyl methacrylate are mixed and dispersed in an irregularly distributed state, and this mixture is present in the mold with a radical initiator. A method for producing a marble-like article, which comprises polymerizing and molding underneath. 4. The particles have a dimensional change rate of 0.1 to 20% or less when the particles are completely immersed in methyl methacrylate (23 ° C. ± 2 ° C., 1 day). 3. The production method described in 3.