JPH0354706B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a patterned cured product that has a natural stone-like appearance and can be easily processed in the same manner as ordinary methacrylic resin plates.

Resin concrete made of polymers such as unsaturated polyester resin, inorganic powders such as calcium carbonate, crushed stone, fine sand, etc. is well known, but such resin concrete can be processed such as cutting, drilling, and gluing to the same extent as plastics. The disadvantage is that it is not easy to implement. Compositions made of inorganic powders such as powder, calcium carbonate, and alumina trihydrate and polymers are also known; If a large amount of powder is contained, there are problems such as severe abrasion of the blades of processing machines such as saws and drills (c) reduced strength of articles obtained from the composition and poor surface abrasion resistance. .

The present invention is a patterned cured product which provides an article free from the above-mentioned drawbacks, and is a cured product comprising a room temperature curable polymer, a fine inorganic powder, and a methacrylic resin powder.

The cured product of the present invention has a spotted pattern similar to natural stone, so it has a beautiful appearance, can be easily processed with a normal plastic processing machine, has less damage and wear to the processing machine blade, and has the same weather resistance as natural stone. It has advantages such as abrasion resistance, flame retardance, and surface hardness, and also has a strength greater than that of natural stone or resin concrete, making it particularly suitable for use as a building material.

The first component of the cured product of the present invention is a room temperature curable polymer. What is a room temperature curable polymer?
℃) and hardens within several hours without losing fluidity. Specific examples include polyurethane resin, epoxy resin, furfural resin, (meth)acrylate resin, and unsaturated polyester resin, but methacrylic resin,
Unsaturated polyester resins are preferred. These resins are mixed as a liquid with the other two components constituting the present invention. When methacrylic resin is used as a room-temperature curable polymer, it has high whiteness and good appearance, and the cured product has excellent processability such as weather resistance, abrasion resistance, surface hardness, and machinability. A cured product with low properties is obtained. A liquid methacrylic resin is one that contains 60% by weight or more of methyl methacrylate monomer units and other copolymerizable monomers such as methacrylic esters, acrylic esters, styrenes, acrylic acid, and ethylene dimethacrylate. The main components are a polymer containing 0 to 40% by weight of mer units and methyl methacrylate (60% by weight or more)
A syrup consisting of a mixture of monomers. When the viscosity (at 25° C.) of the syrup is 0.1 to 20 poise, it is easy to mix with fine inorganic powder and the like, and the air in the mixture is easily defoamed. Such syrup can also be obtained directly as a prepolymerized product by prepolymerizing a mixture consisting of a monomer mainly composed of methyl methacrylate, a radical polymerization initiator, and a chain transfer agent such as a mercaptan compound. Chain transfer agents tend to remain inside, and curing properties tend to be inhibited by air. Polymerized in advance by bulk polymerization or suspension polymerization,
Methacrylic resin with a viscosity average degree of polymerization of 500 to 3000,
When using a syrup obtained by dissolving about 5 to 40% by weight in a monomer containing 60% by weight or more of methyl methacrylate, curing will not be inhibited by oxygen in the air. The surface of the cured product is less sticky and has a beautiful appearance. Methyl methacrylate syrup can be cured at room temperature using a radical polymerization initiator. Since methacrylic resin powder has the property of absorbing methyl methacrylate or dissolving it in syrup, the syrup should be cured for a short time, usually within 3 hours at room temperature.

For room temperature curing, acyl peroxide such as benzoyl peroxide and N,N-dimethylaniline,
By redox polymerization using a combination with an amine compound such as N,N-diethylaniline or N,N-dimethylparaidine, or a combination of a peroxy compound such as tert-butylperoxymaleic acid and a mercaptan compound such as glycol dimercaptoacetate. It can be done with

Unsaturated polyester resins can also be used as room temperature curable resins. The unsaturated polyester resin is prepared from an unsaturated dibasic acid such as maleic anhydride,
Unsaturation obtained by condensation polymerization of isophthalic acid, phthalic anhydride, etc. or these with other acids such as adipic acid, etc., and glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, etc. Liquid polyester as a crosslinking agent,
For example, it can be obtained by crosslinking with styrene, methyl methacrylate, an allyl group-containing compound, or the like. The liquid resin liquid containing the unsaturated liquid polyester preferably has a viscosity of about 0.5 to 20 poise at 25°C, and includes methyl ethyl ketone peroxide,
By redox polymerization using a combination of a peroxide such as cyclohexanone peroxide or acetylacetone peroxide and an accelerator such as cobalt naphthenate or cobalt octoate, or an acyl peroxide such as benzoyl peroxide and an amine compound such as dimethylaniline. Can be cured at room temperature. Since unsaturated liquid polyester does not easily dissolve or swell methacrylic resin powder, it has the advantage that it is easy to produce the cured product of the present invention.
Although the cured product of the present invention using unsaturated polyester resin as a room temperature curable polymer has poor hardness resistance, it has excellent chemical resistance, high surface hardness, and does not easily form pinholes in the cured product. It has the advantage that the surface of the cured product is smooth.

The second component of the cured product of the present invention is a fine inorganic powder. The fine inorganic powder acts as a binder by filling the voids in the methacrylic resin powder together with the room temperature curable polymer, and also prevents air from interfering with the polymerization of the room temperature curable polymer. It has effects such as preventing pinholes from forming inside, coloring the cured product, imparting flame retardancy to provide an inexpensive cured product, and uniformly dispersing methacrylic powder through its thickening effect. vinegar. Specifically, the average particle size is 50 microns or less, usually 0.5~
It is an inorganic powder of about 20 microns. More specifically, calcium carbonate, kaolin, clay, silica sand,
It is a fine inorganic powder such as talc, calcium sulfate, alumina, alumina hydrate, zinc oxide, barium sulfate, titanium oxide, and basic magnesium carbonate. These may be used alone or in combination of two or more. When white fine-grained inorganic powder is used, surface defects of the cured product, such as sink marks (surface irregularities) and pinholes due to polymerization shrinkage, are less noticeable. The fine inorganic powder is preferably used in an amount of at least 30 parts by weight or more per 100 parts by weight of the room temperature curable polymer. When such a large amount of fine inorganic powder is used, the above-mentioned effects are great. If the amount is small, the above-mentioned effects will be lacking.

When a hydrated fine inorganic powder such as alumina trihydrate, basic magnesium carbonate, or calcium sulfate dihydrate is used as the fine inorganic powder, flame retardancy is imparted to the cured product. . In particular, calcium sulfate dihydrate has the advantage that it is neutral, so it does not inhibit the curing reaction and provides a highly transparent cured product, and does not easily thicken the liquid product of room temperature curable polymer. There is. If the fine inorganic powder is 400 parts by weight or more for 100 parts by weight of the room temperature curable polymer,
The strength of the cured product decreases to such an extent that it cannot be put to practical use.

The third component of the cured product of the present invention is methacrylic resin powder. Methacrylic resin means a polymer containing 60% by weight or more of methyl methacrylate units. The methacrylic resin powder should be such that at least half of it does not pass through a 60-mesh, preferably 32-mesh sieve. If the methacrylic resin powder is too small, spots in the cured product will be difficult to observe with the naked eye, making it difficult to provide a natural stone-like appearance. Methacrylic resin powder not only gives the cured product a speckled pattern, but also has the effect of increasing the viscosity of the mixture, shortening the curing time, preventing polymerization interference caused by oxygen in the air, and improving the machinability of the cured product. . Since the spots in the cured product are made of methacrylic resin, the colors of the spots are clear. No deterioration due to light, rain, etc.
It has properties such as high hardness. As the methacrylic resin powder, it is economical to use offcuts or waste materials generated in the methacrylic resin manufacturing process or processing process (for example, the manufacturing process of injection molded products). As a methacrylic resin, the average degree of polymerization is approximately 5000 ~
When 100,000 is used, the mixture is difficult to thicken, so it is particularly easy to produce a cured product, and there is an advantage that the dye and pigment in the powder will not ooze out during curing.

Methacrylic resin powder is added so that the total amount of fine inorganic powder and methacrylic resin powder is 40 to 90% by weight based on the total amount of the mixture of room temperature curable polymer, fine inorganic powder, and methacrylic resin powder. The above-mentioned effect is significantly greater when it is contained.

When a liquid methacrylic resin or unsaturated liquid polyester is cured at room temperature, the methacrylic resin powder maintains its original shape before mixing in the cured product, resulting in a cured product with a beautiful appearance.

After mixing at least three components of a room temperature curable resin, a fine inorganic powder, and a methacrylic resin powder by an appropriate method and order, the resulting mixture is poured into a desired mold to form a certain shape. A cured product (for example, a plate-like body) can be produced. Additionally, useful coatings can be applied to the surface of any substrate, such as textiles, plastics, walls of architectural structures, roads, etc., or laminates with textiles, metals, plastics, etc. It is also possible to manufacture.

The cured product of the present invention requires the above-mentioned three components, but depending on the purpose, other additives such as reinforcing materials such as metal plate glass fiber, asbestos, and crushed stone, ultraviolet absorbers,
It may further contain dyes, pigments, plasticizers, mold release agents, flame retardants, etc.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Parts and percentages are by weight.

Example 1 A 30% copolymer with a viscosity average degree of polymerization of 750, consisting of 90% methyl methacrylate units and 10% methyl acrylate units obtained by suspension polymerization,
A methyl methacrylate syrup consisting of 0.1% N-diethyl-paratoluidine and 69.9% methyl methacrylate was obtained.

On the other hand, a black opaque plate of methyl methacrylate resin with a viscosity average degree of polymerization of 20,000 obtained by the bulk polymerization method was pulverized using a pulverizer to obtain a black powder of methacrylic resin. The particle size distribution of the powder was 80% between 16 and 32 meshes, 10% between 32 and 42 meshes, 5% between 42 and 60 meshes, and 5% between 60 meshes. Add 0.1 part of benzoyl peroxide to 25 parts of the above methyl methacrylate syrup, then add 1 part of titanium oxide and fine powder of calcium sulfate dihydrate (average particle size 2 microns, all 2 passing through a 200 mesh sieve). ) was added and mixed, and then the black powder of the methacrylic resin mentioned above was added and mixed.
25 parts were added to obtain a mixture. Next, the mixture was poured into a mold and cured at 25°C, and then heated at 80°C for 3 hours to obtain a cured plate with a thickness of 15 mm. The mixture is 25
It cured in about 60 minutes in a ℃ atmosphere, and was a completely cured product with no tackiness on the surface (3). A lit burner was brought close to one end of the cured product and exposed to flame for 20 seconds, but the cured product did not ignite. The obtained cured plate has black powder of methacrylic resin on the surface and inside (1)
The black dye in the black powder of the methacrylic resin did not ooze out at all, and the black powder maintained its original shape in the cured product.

The cured board could be cut with a circular saw cutting machine for plastics (vertical automatic cutting machine NTVA-7 model manufactured by Nisshin Sangyo Co., Ltd.). The surface hardness of the hardened plate is 90 (M scale,
According to ASTMD785), its bending strength is
It was 320Kg/ ^cm2 . In other words, flame retardancy, design,
It has excellent workability and physical properties, and can be used as an alternative to natural stone as an indoor architectural wall tile.

Example 2 Viscosity average degree of polymerization 900 consisting of 95% methyl methacrylate units and 5% ethyl acrylate units
After dissolving 30 parts of the copolymer of N,
A syrup was obtained by adding and mixing 0.2 part of N-dimethylol para-toluidine.

On the other hand, the viscosity average polymerization degree is
Obtain a colorless transparent plate of 10,000 methacrylic resin and crush it to obtain a colorless and transparent powder of methacrylic resin (particle size distribution: 3-6 mesh is 35%, 6-16 mesh is 60%).
%, and those passing 32 meshes were 5%).

100 parts of the syrup of this agent, 0.4 parts of benzoyl peroxide, 70 parts of fine powder of calcium carbonate (average particle size 4 microns, all passed through a 200 mesh sieve), colorless transparent powder of methacrylic resin of this example A mixture was obtained by mixing 150 parts of the same.

The mixture was cast into a mold, left at room temperature (25° C.) for 60 minutes to harden, and then immediately removed from the mold to obtain a hard plate with a thickness of 10 mm. The base color of the hard board (2) is white, and the surface and inside are colorless and transparent methacrylic resin powder (1)
However, the patterned plate did not lose its shape when mixed and had no tackiness on the surface. The bending strength of a hard plate is
It was large at 400Kg/cm ² , and no changes in appearance such as yellowing were observed even though it was left outdoors for half a year.

The hard plate could be easily cut with the circular saw cutter of Example 1, and no wear or chipping of the saw blade was observed. Using a hard plate as the bottom plate and a colorless and transparent methacrylic resin plate as the side plate, it was possible to easily assemble the cosmetic case by solvent adhesion using methylene chloride. Furthermore, a part of the real hard board is cut with a circular saw, a person's name is engraved with an engraving machine, and it is inked with black ink mainly composed of thinner. A natural stone-like nameplate could be easily created as an alternative to the original.

Example 3 After obtaining an unsaturated liquid polyester through a condensation reaction, styrene monomer was added to obtain a liquid resin liquid having a viscosity of 4 poise at 25°C.

On the other hand, a white opaque plate of methacrylic resin with a viscosity average degree of polymerization of 8000 was created by bulk polymerization of methyl methacrylate, and it was crushed to produce a white powder of methacrylic resin (particle size distribution, 85% 6-16 mesh, 16-32 mesh 10%, and 5% passed through 32 meshes). After adding and mixing 0.1 part of cobalt naphthenate solution and 0.2 part of methyl ethyl ketone peroxide solution to 25 parts of the resin liquid of this example, 45 parts of the fine powder of calcium sulfate dihydrate used in Example 1 was added and mixed, and then 30 parts of white powder of methacrylic resin was added to obtain a mixture. The mixture was cast and kept at room temperature (25°C).
After being left for 3 hours, the mold was removed to obtain a cured plate with a thickness of 10 mm. It is a semi-transparent patterned board with white spots (1) of methacrylic resin dotted on the surface and inside of the hardened board without damaging its original shape, giving it a tasteful beauty not found in natural stone. The cured board of this example could be easily cut with the circular saw of Example 1, and could be used indoors as a floor tile. The bending strength is 250Kg/ ^cm2 , and the Rockwell hardness is 105 (according to M scale, ATTMD785).
It was hot. When a lit burner was brought close to one end of the hardened board and exposed to the flame for 20 seconds, the hardened board ignited, but the flame disappeared when the burner was removed.

Example 4 40 parts of the resin liquid of Example 3, 0.2 part of cobalt naphthenate solution, 0.4 part of methyl ethyl ketone peroxide solution, 30 parts of the calcium carbonate fine powder of Example 2
A mixture consisting of 30 parts of the white powder of the methacrylic resin of Example 3 was poured into a mold, left to harden at room temperature (25°C) for 2 hours, and removed from the mold after 16 hours (a 7 mm thick cured plate was prepared). The smooth surface (4) of the cured board can be easily polished with abrasive paper, and the clear white spots (1) of methacrylic resin are replaced by a white background (slightly brown colored) made of unsaturated polyester resin and calcium carbonate (2). )
The polished plate has a beautiful appearance that is not found in natural stones scattered around the world, and has no pinholes on its surface. This board was hard and could be used as an indoor shelf material in place of natural stone. While using it as a shelf material, the surface got dirty, but with cleanser,
Dirt can be removed by polishing with abrasive paper, and since the structure is homogeneous, no difference in appearance between the polished portion and the unpolished portion was noticeable to the naked eye. The bending strength of the cured plate of this example was 300 Kg/cm ² .

Example 5 Methyl methacrylate syrup 40 of Example 1
part, 45 parts of fine powder of alumina hydrate (average particle size: 3 microns), 0.2 parts of benzoyl peroxide, purple transparent powder of methacrylic resin (particle size distribution: 6 to 16)
A cured plate having purple dots (1) was obtained in the same manner as in Example 1 using a mixture consisting of 15 parts of mesh (100% mesh, viscosity average degree of polymerization 15,000). The spots were bright in color and large in size, and had a beautiful appearance. A combustion test was conducted in the same manner as in Example 3, and the cured board was found to be self-extinguishing.

Claims (1)

[Claims] 10 to 60% by weight of room temperature curable polymer of methacrylic resin or unsaturated polyester resin and average particle size
A total amount of 90 to 40% by weight of fine inorganic powder of 0.5 to 50μ and more than half of the methacrylic resin powder that does not pass through a 60 mesh sieve, and the polymer
A patterned cured product characterized by containing at least 30 parts by weight of fine inorganic powder per 100 parts by weight.