JP2000319055A - Polymerizable composition, molding thereof and production of molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain artificial granite of a homogeneous non-porous solid material, having excellent executing property, workability, easy maintenance property, impact resistance and weather resistance and containing uniformly distributed particles capable of exhibiting a stone pattern by specifying the difference of the density between a polymerizable liquid consisting essentially of methyl methacrylate and the particles in a polymerizable composition composed of the polymerizable liquid and the particles. SOLUTION: The polymerizable composition has <=100 kg/m3 difference of density between the polymerizable liquid and the particles. At least one of the polymerizable liquid and the particles preferably contains an inorganic filler or one of the polymerizable and the particles preferably contains a pigment. The polymerizable liquid consists essentially of methyl methacrylate and a syrup composed of MMA alone or a mixture of the polymer of MMA with MMA or the like is exemplified. As the particles, particles composed of the polymer of a radical polymerizable vinyl monomer, the polycarbonate, polyethylene terephthalate or the like are mentioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polymerizable composition, a molded product thereof, a stone-like molded product, and a method for producing the molded product.

[0002]

2. Description of the Related Art Natural granite has long been used as a wall material, a flooring material, and various top boards because of its elegance, but is heavy and hard, and therefore difficult to construct and process. Further, since the surface is porous, it is difficult to remove dirt. Furthermore, it is difficult to obtain a long product because it is a natural product, and large-sized products obtained by connecting a plurality of natural granites have drawbacks such as a seam.

In order to improve these drawbacks, as a natural granite-like artificial material, a melamine veneer, a gel coat artificial granite having only a patterned surface, an acrylic artificial granite, a polyester artificial granite, and the like have been developed. . These are lighter and nonporous than natural granite, but the former two have drawbacks such as patterning only on the surface, which makes processing and repair difficult and, furthermore, they are weak against impact.

On the other hand, acrylic artificial granite and polyester artificial granite have an elegant texture unique to solid materials, easy workability, excellent strength, and impact resistance. In particular, acrylic artificial granite has poor weather resistance. It has many advantages such as excellence.

[0005] Japanese Patent Publication No. 5-502269 discloses a granite-like acrylic product obtained by polymerizing and curing an acrylic syrup containing granular poly (methyl methacrylate).

[0006] WO 97/14749 discloses an acrylic composition characterized by containing particulate polymethyl methacrylate having a specified amount of a copolymerizing monomer and a crosslinking agent.

Japanese Patent Publication No. 61-24357 discloses a model granite comprising a polymer such as polymethyl methacrylate, a filler such as aluminum hydroxide, opaque particles of 200 μm or more and at least one of translucent and transparent particles. Is disclosed. Further, Japanese Patent Publication No. 7-17424 discloses a synthetic material comprising a polymer such as polymethyl methacrylate, a filler such as aluminum hydroxide, and opaque particles having a particle size of 0.05 to 0.5 mm and 0.5 to 1.5 mm. The stone and its method of manufacture are described.

Further, Japanese Patent Application Laid-Open No. 4-504402,
JP-A-8-333148, JP-A-9-2857 and JP-A-9-188556 disclose a stereoscopic effect produced from a combination of a plurality of types of particles having a specific particle size distribution, shape and color. There is disclosed an artificial granite having an appearance similar to that of a natural granite which is rich in natural granite.

[0009] Such artificial granite is characterized by its elegant texture, excellent strength, weather resistance, and ease of construction and processing, so that it can be used for kitchen top plates, vanities, tables, furniture, wall materials, flooring materials, interior accessories, It is used for many purposes, such as seals, bathtubs, window frames, and indirect lighting panels, and its usage is increasing.

[0010]

However, the artificial granite having a stone-tone pattern according to the prior art has particles exhibiting a stone-tone pattern in the process of polymerizing and curing a polymerizable liquid containing methyl methacrylate as a main component. Depending on its specific gravity, it sinks or floats, and the resulting artificial granite has a different appearance on both sides and lowers its commercial value. In addition, in order to prevent sedimentation and floating of particles, operations such as extremely increasing the curing speed using a specific polymerization curing agent and extremely increasing the viscosity of the polymerizable liquid are performed. The degree was low.

It is an object of the present invention to provide the characteristics of conventional acrylic artificial granite and the like, namely, uniform and non-porous solid material, workability and workability equivalent to hard wood, ease of maintenance, impact resistance. An object of the present invention is to provide an artificial granite having a stone-grain pattern in which particles exhibiting a stone-grain pattern are uniformly distributed while having properties and weather resistance.

[0012]

The gist of the present invention is to provide a polymerizable composition comprising a polymerizable liquid (a) containing methyl methacrylate as a main component and particles (b). The polymerizable composition is characterized in that the difference in density from the particles (b) is within 100 kg / m ³ .

It is preferable that at least one of the polymerizable liquid (a) and the particles (b) contains an inorganic filler (c).

It is preferable that at least one of the polymerizable liquid (a) and the particles (b) contains a pigment (d).

The gist of the present invention resides in a stone-like molded product obtained by polymerizing and curing the above polymerizable composition.

Further, the gist of the present invention is a process for producing a grain-like molded product, which comprises polymerizing and curing a polymerizable composition comprising a polymerizable liquid (a) containing methyl methacrylate as a main component and particles (b). A method for producing a stone-grained molded product, characterized in that the difference in density between the polymerizable liquid (a) and the particles (b) is within 100 kg / m ³ .

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The polymerizable liquid (a) constituting the polymerizable composition of the present invention contains methyl methacrylate (hereinafter referred to as "MMA" as appropriate) as a main component. Polymerizable liquid (a)
As a syrup composed of MMA alone, a mixture of a polymer of MMA and MMA, and one MMA and one vinyl group in the molecule.
(Hereinafter, appropriately referred to as "MMA-containing mixture"), and a syrup composed of a polymer of the MMA-containing mixture and the MMA-containing mixture. The total content of MMA and components derived from MMA in the polymerizable liquid (a) is preferably at least 80% by weight.

This polymerizable liquid (a) is preferably a syrup. In the case of syrup, the viscosity of the syrup can be easily adjusted by adjusting the content and the molecular weight of the polymer. Therefore, when inorganic fillers and particles are added to the syrup, sedimentation and floating of these additives can be easily prevented, and the appearance of the obtained grain-like molded product is improved.

In order to produce syrup, a method of polymerizing MMA and stopping the polymerization in the middle, or a method of polymerizing MMA as a main component by bulk polymerization or suspension polymerization, is used. Examples thereof include a method of dissolving in a monomer. The viscosity of the syrup can also be adjusted to a desired viscosity by diluting with a monomer. The syrup viscosity at 25 ° C. is preferably in the range of 0.02 to 5 Pa · s.

Other vinyl monomers having one vinyl group in the molecule include styrene, vinyl acetate and acrylonitrile; ethyl methacrylate, butyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, and methacrylic acid 2 (Hydroxyethyl, glycidyl methacrylate, ethyl acrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and the like, and (meth) acrylates other than MMA. The total content of other vinyl monomers and components derived from other vinyl monomers in the polymerizable liquid (a) is preferably 20% by weight or less.

The polymerizable liquid (a) may contain a crosslinkable monomer. This is a component for generating a cross-linking in a polymer obtained by polymerizing the polymerizable liquid (a) containing MMA as a main component.

Examples of the crosslinking monomer include compounds having two or more vinyl groups in the molecule, such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and trimethylolpropane trimethacrylate. (Meth) acrylic acid esters and the like.

The content of the crosslinking monomer is preferably from 0.05 to 5.0% by weight, more preferably from 0.1 to 3.0% by weight, based on the polymerizable liquid (a). If the content of the crosslinkable monomer is too low, the resulting stone-like molded product will have reduced stain resistance and the like. If the content is too high, the workability, crack resistance, impact resistance, etc. of the stone-grained molded product deteriorate.

The content of the polymerizable liquid (a) is preferably from 60 to 95% by weight, more preferably from 70 to 95% by weight, based on the total amount of the polymerizable composition.

The particles (b) constituting the polymerizable composition of the present invention include a polymer of a radical polymerizable vinyl monomer, polycarbonate, polyethylene terephthalate,
Various engineering plastics such as polybutylene terephthalate, polyacetal, and polyamide, epoxy resin, unsaturated polyester resin, vinyl ester resin,
Particles (b) made of a thermosetting resin such as a melamine resin, a phenol resin, a polyallyl resin, and an alkyd resin are exemplified.

Among these, a crosslinked polymer of a radical polymerizable vinyl monomer containing MMA or styrene as a main component and crosslinked with a crosslinkable monomer, polycarbonate, polyethylene terephthalate, polybutylene terephthalate,
Polyamide, epoxy resin, unsaturated polyester resin,
Particles (b) made of a vinyl ester resin are preferred, and a crosslinked polymer is most preferred.

As the radical polymerizable vinyl monomer,
Known ones are mentioned. For example, MMA, the aforementioned (meth) acrylates; acrylic acid, methacrylic acid,
Α, β-unsaturated carboxylic acids such as maleic acid and itaconic acid; unsaturated carboxylic anhydrides such as maleic anhydride and itaconic anhydride; maleimide derivatives such as N-phenylmaleimide, N-cyclohexylmaleimide and N-butylmaleimide A hydroxy group-containing vinyl monomer such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, or 2-hydroxypropyl methacrylate; acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, diacetone acrylamide; Nitrogen-containing vinyl monomers such as dimethylaminoethyl methacrylate; epoxy-containing vinyl monomers such as allyl glycidyl ether, glycidyl acrylate, and glycidyl methacrylate; styrene, α-methyl Styrene monomers such as Rusuchiren, ethylene, propylene, butadiene, 4-methyl-1-olefin monomer, such as pentene, vinyl chloride,
Halogen group-containing vinyl monomers such as vinylidene chloride; and crosslinkable monomers such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, allyl acrylate, allyl methacrylate, divinylbenzene, and trimethylolpropane triacrylate. These radically polymerizable vinyl monomers are used alone or in combination of two or more.

When the particle (b) is a crosslinked polymer, the content of the crosslinkable monomer unit in the particle (b) is 0.05 to 20.0% by weight based on the particle (b). Preferably, 0.
More preferred is 1-5.0% by weight.

The particle size of the particles (b) is 0.1 to 5.0 m
m is preferable. If the particle size is too small, the appearance of the obtained grain-like molded product is deteriorated. If it is too large, the impact resistance, crack resistance, and the like of the stone-like molded product deteriorate. The particle diameter of the particles (b) may be in a narrow range, for example, from 0.24 to 2.8 mm. Also, for example, 0.1 to 0.
Opaque particles having a color tone of 5 mm, particle diameter 0.5-1.
Opaque particles having a different color of 7 mm and a particle diameter of 1.7
It may be a combination of particle groups having different particle diameters composed of a group of translucent particles having a size of about 5.0 mm.

The particles (b) may be beads produced by a known suspension polymerization method, plate-like products produced by a known bulk polymerization method, or pulverized products from scrap. Examples of the pulverization method include a ball mill, a rod mill, a tower-type attritor, a vibration mill, a roll mill, a brake crusher, a roll crusher, a hammer mill, a jet mill, a fluid pulverization, and the like.

The content of the particles (b) is preferably in the range of 5 to 40% by weight, more preferably 5 to 30% by weight, based on the total amount of the polymerizable composition.

The polymerizable liquid (a) contains an inorganic filler (c)
Can be contained. The particles (b) can also contain an inorganic filler (c).

Examples of the inorganic filler (c) include aluminum hydroxide, magnesium hydroxide, calcium carbonate, and silica. These can be used alone or in combination of two or more. Aluminum hydroxide is preferred, and gypsite, which is alumina trihydrate, is more preferred.

As the inorganic filler (c), those obtained by treating the particle surface with, for example, a silane coupling agent, a phosphate ester coupling agent, a titanate coupling agent, stearic acid or the like can be used. . When the inorganic filler treated by these is used, the strength and water resistance of the obtained grain-like molded product can be improved as compared with the untreated inorganic filler (c).

When the inorganic filler (c) is contained in both the polymerizable liquid (a) and the particles (c), the same inorganic filler or different inorganic fillers may be used.

The size of the inorganic filler (c) is preferably one having an average particle diameter of 1 to 100 μm, and 5 to 50 μm.
m is more preferred.

The content of the inorganic filler (c) is preferably 0.1 to 60% by weight in the polymerizable liquid (a) or the particles (b). If the content is too high, the strength and impact resistance of the obtained stone-grained composition decrease.

The density difference between the particles (b) and the polymerizable liquid (a) is within 100 kg / m ³ . If the density difference is within this range, in the process of polymerizing and curing the polymerizable liquid (a),
Since the particles (b) for expressing the stone-like pattern do not settle or float, a molded product having a high commercial value with the same front and back appearance of the molded product can be obtained. In order to keep the density difference within this range, a method of changing the type of a monomer constituting the particles (b), a method of adding an inorganic filler (c) to the particles (b), and the like can be mentioned. Further, a method of changing the content of the polymer constituting the polymerizable liquid (a), a method of adding an inorganic filler (c) to the polymerizable liquid (a), and the like can be mentioned. It is preferable that the density difference is small. 100kg density difference
/ M ³ , the density of either the particles (b) or the polymerizable liquid (a) may be high.

In the production method of the present invention, since the density difference between the polymerizable liquid (a) and the particles (b) is within 100 kg / m ^3, it is specified to prevent the particles (b) from settling or floating. There is no need for an operation such as extremely increasing the curing speed or extremely increasing the viscosity of the liquid by using the polymerization curing agent of (1), and the production method has a high degree of freedom.

The density of the polymerizable liquid (a) containing the inorganic filler (c) is determined by the apparent density obtained by dividing the weight of the polymerizable liquid (a) containing the inorganic filler (c) by its volume. is there. The density of the particles (b) containing the inorganic filler (c) is also the apparent density obtained by dividing the weight of the particles (b) containing the inorganic filler (c) by the volume.

The pigment (d) can be contained in the polymerizable liquid (a). Further, the pigment (d) can be contained in the particles (b).

Examples of the pigment (d) include inorganic pigments such as titanium dioxide, barium sulfate, zinc sulfide, zinc oxide, iron oxide, carbon black, red iron red, cadmium red, yellow lead, cobalt blue, and cobalt purple; Organic pigments such as azo, triphenylmethane, quinoline and the like can be mentioned. The content of these pigments (d) is 0.0001 based on the polymerizable liquid (a) or the particles (b).
~ 5% by weight is preferred.

When the pigment (c) is contained in both the polymerizable liquid (a) and the particles (c), the same pigment or different pigments may be used.

Various additives can be contained in the grain-like molded product of the present invention. Examples of the additive include an ultraviolet absorber, a flame retardant, an antibacterial agent, a release agent, a fluidizing agent, a thickener, and the like. The additive can be contained in the particles (b) in the stone-like molded article. It can also be contained in portions other than the particles (b).

The polymerizable composition of the present invention is prepared by adding a polymerizable liquid (a), particles (b), and, if necessary, a polymerization initiator and various additives for polymerization and curing, and using a conventional stirring vessel with stirring blades. Or by mixing using a twin-screw kneader. The viscosity of the polymerizable composition is 0.2 at 25 ° C.
1 to 10 Pa · s is preferable, and 0.1 to 5 Pa · s is more preferable. If the viscosity is too low, the particles (b) and the inorganic filler (c) tend to settle and float. If it is too high, operations such as liquid transfer during production become difficult, and the productivity is extremely reduced.

Examples of the method of polymerizing and curing the polymerizable composition include a method of adding a heat-reactive polymerization initiator and performing heat polymerization, a method of performing redox polymerization, and the like.

Examples of the polymerization initiator include hydrogen peroxide, benzoyl peroxide, t-butylperoxymaleic acid, acetyl peroxide, lauryl peroxide, t-butyl perbenzoate, t-butyl peroxyvivalide, and t-butyl. Organic peroxides such as peroxyneodecanoate, t-butylperoxyoctoate, and diisopropylperoxydicarbonate, and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile are exemplified. A combination of an acyl peroxide such as benzoyl peroxide and an amine compound such as N, N-dimethylaniline, N, N-diethylaniline, N, N-dimethylparaidine; or t.
Redox systems such as a combination of a peroxyl compound such as -butylperoxymaleic acid and a mercaptan compound such as ethylene glycol dimercaptoacetate. These may be used alone or in combination of two or more. The polymerization initiator, based on the polymerizable composition,
Preferably it is 0.01 to 5.0% by weight.

In the method of redox polymerization, when a polymerization initiator is mixed with the polymerizable liquid (a), the polymerization proceeds rapidly, and the polymerizable liquid (a) thickens, so that particles (0.5 mm or less in size) are used. In the case of b), there is an advantage that sedimentation and floating hardly occur. However, since the viscosity is so fast, there is a restriction in the process such that the initiator must be mixed immediately before molding.
Therefore, in the present invention, a method of adding a heat-reactive polymerization initiator and performing heat polymerization is particularly preferable.

As a method of molding by polymerization and curing, a batch casting method, a batch press molding method, a continuous cast molding method and the like are known. However, the production cost and the appearance and physical properties of the obtained molded product are known. From the standpoint of comprehensively determining the stability and the like, a continuous cast molding method is preferred.

The surface of the formed grain-like molded product can be further ground to further enhance the granite appearance.

[0051]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

In the following examples, styrene syrup was composed of 20% by weight of styrene polymer and 80% of styrene.
% Syrup having a viscosity at 25 ° C. of 3 Pa · s. As methyl methacrylate syrup, 20% by weight of MMA polymer and MMA
80% by weight, and a syrup having a viscosity at 25 ° C. of 0.6 Pa · s was used.

As aluminum hydroxide, Hijilite H-210 (manufactured by Showa Denko KK, average particle diameter 31)
μm) or BW103ST (manufactured by Nippon Light Metal Co., Ltd., surface-treated with an average particle diameter of 8 μm). Zelek UN (manufactured by DuPont) was used as a release agent.

Reference Example White opaque particles (b-1)
(B-4) and black opaque particles (b-5) to (b-8)
This is an example of the production of

The components were mixed in the amounts shown in Table 1 and degassed under vacuum with stirring. This vacuum degassed mixture was poured into a cell formed by two glass plates on which a polyester film was stuck and a gasket made of polyvinyl chloride. Thereafter, polymerization was carried out at 82 ° C. for 2 hours and at 130 ° C. for 1 hour to obtain a plate having a thickness of 6 mm. Then, the plate was cut by a cutting machine, pulverized by a hammer mill, and the pulverized material was separated by a sieve to obtain a particle diameter of 0.1.
Eight types of particles (b-1) to (b-8) having a size of 0.5 mm were obtained.

[0056]

[Table 1] Example 1 The components of the polymerizable liquid were mixed in the amounts shown in Table 2 to obtain a polymerizable liquid (a) having a density of 1000 kg / m ³ . A density of 1060 kg / m ^{3 was} added to the polymerizable liquid (a).
Was mixed with 5 parts by weight of the white opaque particles (b-1) and 15 parts by weight of the black opaque particles (b-5), followed by vacuum degassing while stirring. The vacuum degassed polymerizable composition was poured into a cell formed of two mirror-finished stainless steel plates and a polyvinyl chloride gasket. Thereafter, polymerization was carried out at 82 ° C. for 1 hour and at 130 ° C. for 1 hour to obtain a stone-like molded product having a thickness of 3 mm.

The obtained stone-grained molded product had a granite-like appearance, did not cause sedimentation or floating of particles, had the same appearance on both sides of the molded product, and had high commercial value. .

[Examples 2 and 3] In the same manner as in Example 1 except that the components and amounts of the polymerizable liquid (a) and the types and amounts of the particles (b) were changed as shown in Table 2, A stone-like molded product was obtained. The obtained stone-grain-like molded product had a granite-like appearance, did not cause sedimentation or floating of particles, had the same appearance on both sides of the molded product, and had high commercial value.

[Comparative Examples 1 and 2] In the same manner as in Example 1 except that the components and amounts of the polymerizable liquid (a) and the types and amounts of the particles (b) were changed as shown in Table 2, A stone-like molded product was obtained.

Although the obtained stone-grained molded product has a granite-like appearance, the sedimentation of particles is remarkable,
The appearance was different between the front and back of the molded product.

[0061]

[Table 2]

[0062]

The stone-grain-like molded product of the present invention has the characteristics of conventional acrylic artificial granite and the like, namely, uniform and non-porous solid material, workability and workability equivalent to hard wood, and maintenance. In addition, particles exhibiting a stone-like pattern while having ease of use, impact resistance, weather resistance, and the like are uniformly distributed. Further, the polymerizable composition of the present invention is suitable for a composition for obtaining the above stone-grained molded product. Further, the method for producing a stone-grained molded product of the present invention is suitable for a production method for obtaining the above-mentioned molded product.

Claims (5)

[Claims] 1. In a polymerizable composition comprising a polymerizable liquid (a) containing methyl methacrylate as a main component and particles (b), the density difference between the polymerizable liquid (a) and the particles (b) is 10%.
A polymerizable composition having a weight of 0 kg / m ^{3 or} less. 2. The polymerizable composition according to claim 1, wherein at least one of the polymerizable liquid (a) and the particles (b) contains an inorganic filler (c). 3. The polymerizable composition according to claim 1, wherein at least one of the polymerizable liquid (a) and the particles (b) contains a pigment (d). 4. A grain-like molded product obtained by polymerizing and curing the polymerizable composition according to any one of claims 1 to 3. 5. A method for producing a stone-like molded article, wherein a polymerizable composition comprising a polymerizable liquid (a) containing methyl methacrylate as a main component and particles (b) is polymerized and cured. ) And the particle (b) have a density difference of 100 kg / m ^3.
A method for producing a stone-grained molded product, characterized in that: