JPS63122747A - Manufacturing method of acrylic 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 method for producing methyl methacrylate-based artificial marble filled with aluminum hydroxide powder. More specifically, the present invention relates to a highly productive method for producing methyl methacrylate-based artificial marble filled with aluminum hydroxide powder that has excellent heat resistance and corrosion resistance.

Acrylic resin molded products filled with inorganic powder and unsaturated polyester resin molded products are widely used as artificial marble products, but acrylic artificial marble products filled with aluminum hydroxide powder have a deep and beautiful appearance. Due to its characteristics such as surface quality, excellent mechanical strength, excellent corrosion resistance, and excellent flame retardancy, it is suitable for various tabletops, countertops, vanities, sinks, bathtubs, and shower trays. , waterproof pans, flooring materials, wall materials,
Widely used for partition boards, arts and crafts, etc. These acrylic artificial marble products filled with aluminum hydroxide powder are often manufactured by casting a slurry in which aluminum hydroxide powder is dispersed in a methyl methacrylate polymerizable monomer or its syrup. However, methyl methacrylate polymerizable monomers or their syrups inherently polymerize more slowly than unsaturated polyester resins, and their low boiling points make polymerization difficult at high temperatures, resulting in slow curing. In order to shorten the molding cycle and improve economic efficiency, there is a need for rapid curing comparable to that of unsaturated polyester resins. Polymerization and curing at high temperature under pressure is known as one of the fast curing methods, but methyl methacrylate polymerizable monomers or their syrups are difficult to thicken like unsaturated polyester resins, so the slurry viscosity is low. It is not generally applied because the pressure is low and pressurization is difficult. Separately, there is a known method to efficiently obtain artificial marble products by filling an acrylic polymer with aluminum hydroxide powder and then using injection molding or extrusion molding. Therefore, it has the disadvantage of poor heat resistance and corrosion resistance.

In addition, the flame retardance of the aluminum hydroxide powder-filled acrylic artificial marble is that the aluminum hydroxide powder contained as a filler has a large amount of bound water of 34.5% in total.
This is because it causes a rapid dehydration decomposition reaction at around 200°C and at the same time absorbs a large amount of heat.If a large amount of aluminum hydroxide powder is added to ordinary flammable plastic, it will meet the UL standard 94. It is also possible to impart flame retardancy that passes V-0. However, artificial marble made by casting a slurry of aluminum hydroxide powder dispersed in conventional methyl methacrylate-based polymerizable monomers or its syrup has a high burning speed when exposed to flame, and the flames burn on the back side. It has the disadvantage of being easy to penetrate, so if it is used for partition plates or wall materials, the flames will spread quickly in the event of a fire, creating a problem in initial fire extinguishing.

In order to delay the penetration of the flame to the back side, it is possible to increase the thickness of the artificial marble product, but this increases the material and transportation costs, which is economically disadvantageous.

There is also a known method of adding large amounts of flame retardants such as halogens, antimony trioxide, etc., but this method requires a large amount of flame retardants to be used in acrylic artificial marble products filled with aluminum hydroxide powder. Properties such as excellent depth, heat resistance, weather resistance, corrosion resistance, and strength are lost.

(Problems to be Solved by the Invention) The present invention provides a methyl methacrylate-based artificial marble product filled with aluminum hydroxide powder that has excellent depth, heat resistance, corrosion resistance, weather resistance, flame penetration resistance, strength, etc. The aim is to provide an efficient manufacturing method.

(Means for Solving the Problems) The inventors of the present invention have made extensive studies to solve the above problems, and as a result, have come up with the present invention. That is, (a) consists of 30 to 50% by weight of an acrylonitrile-styrene copolymer resin and 70 to 50% by weight of a polymerizable monomer whose main component is methyl methacrylate, based on the total amount of syrup. If a slurry made by mixing 20 to 60 parts by weight of syrup and (b) 80 to 40 parts by weight of aluminum hydroxide powder in a total amount of 100 parts by weight is shaped under pressure and polymerized and hardened at the same time, heat resistance is achieved. discovered that it is possible to efficiently produce methyl methacrylate-based artificial marble products filled with aluminum hydroxide powder, which have excellent corrosion resistance, flame resistance, etc.
The present invention has been completed.

In the present invention, the polymerizable monomer mainly composed of methyl methacrylate means methyl methacrylate alone or 5
Less than 0% by weight is substituted with other α,β-unsaturated compounds. α, β- that can replace methyl methacrylate
The unsaturated compound is not particularly limited as long as it is compatible with methyl methacrylate and can be copolymerized with methyl methacrylate. Examples of such substances include acrylic acid, esters of monohydric alcohols and methacrylic acid, olefinic nitriles such as acrylonitrile and metacyclonitrile, olefinic amides such as acrylamide and methacrylamide, styrene and α-methylstyrene. Aromatic unsaturated compounds such as, Ichinomiya functional monomers such as vinyl esters such as vinyl acetate and vinyl benzoate, and acrylic acid and methacrylic acid and ethylene glycol, polyethylene glycol, polypropylene glycol, 1,3
-butazinol, neopentyl glycol, 1.6-
Polyesters with polyhydric alcohols such as hexanediol, trimethylolethane, trimethylolpropane, tetramethylolmethane, pentaerythritol, dipentaesritol, and polyfunctional monomers such as divinylbenzene, diallyl phthalate, triallyl cyanurate, etc. Examples include, but are not limited to, the body. α, β- that can replace methyl methacrylate
Two or more types of unsaturated compounds may be used.

Furthermore, a part of the composition of the polymerizable monomer containing methyl methacrylate as a main component can be polymerized in advance and used as a polymer solution.

In addition, in the thermoplastic polymer injection molded products and extrusion molded products filled with aluminum hydroxide powder mentioned above, the molecular weight of the polymer is set low in consideration of fluidity during molding, whereas polymerization under pressure is Cured artificial marble products have high molecular weight polymers, so they themselves have excellent heat resistance and corrosion resistance, but it is desirable to use polyfunctional monomers to roughly enhance these properties. Furthermore, since the polyfunctional monomer has the effect of suppressing the penetration of flame when the artificial marble product mentioned above is exposed to flame, its use is also desirable from this point of view. However, since polyfunctional monomers make artificial marble products brittle, the cylinder used is preferably 0.5 to 20% by weight, based on the total amount of polymerizable monomers whose main component is methyl methacrylate. More preferably, it is 1 to 10% by weight.

The acrylonitrile-styrene copolymer resin as used in the present invention refers to a copolymer resin of acrylonitrile and at least one styrene selected from the group consisting of styrene, α-methylstyrene, and p-methylstyrene. It is also possible to use a mixture of two or more types, and specifically, acrylonitrile-styrene copolymer resin, acrylonitrile-α-methylstyrene copolymer resin, acrylonitrile-p-methylstyrene copolymer resin, acrylonitrile-α-methyl Styrene-p-methylstyrene copolymer resin, acrylonitrile-α-methylstyrene-styrene copolymer resin, acrylonitrile-p-methylstyrene-styrene copolymer resin, acrylonitrile-α-methylstyrene-p-methylstyrene-styrene copolymer resin, etc. It is.

Such acrylonitrile-styrene copolymer resin is used to give artificial marble products a sense of depth.It is dissolved in a polymerizable monomer whose main component is methyl methacrylate, and the amount of polymerization and hardening of the syrup is transparent or milky. It is necessary that it be semi-transparent, and most preferably it is transparent. The composition of acrylonitrile-styrene copolymer resin having such properties varies depending on the composition of the polymerizable monomer whose main component is methyl methacrylate, but in the case of acrylonitrile-styrene copolymer resin, the composition of the resin monomer The composition has an acrylonitrile content of 20 to 50 mol%,
The intrinsic viscosity measured at 25°C using tetrahydrofuran as a solvent is 0.2 to 2 d/CJ, preferably 0.5 to 16
N/Ω. For example, if the polymerizable monomer whose main component is methyl methacrylate is methyl methacrylate,
When the monomer composition of the acrylonitrile-styrene copolymer resin has an acrylonitrile content of 40 mol%, the polymerized and cured syrup becomes transparent.

The amount of acrylonitrile-styrene copolymer resin added to a polymerizable monomer mainly composed of methyl methacrylate is:
It is 30-50% by weight, preferably 40-50% by weight, based on the total amount of syrup. When the amount of acrylonitrile-styrene copolymer resin added is less than 30% by weight,
Slurry obtained by mixing syrup with aluminum hydroxide powder has a low viscosity, so it is sticky and difficult to handle, and pressure is not applied during pressure polymerization and curing, which is not preferable. Moreover, if it exceeds 50% by weight, the viscosity of the syrup increases, which limits the amount of aluminum hydroxide powder to be filled and deteriorates the weather resistance and other properties of the artificial marble product, which is not preferable.

The aluminum hydroxide powder used in the present invention is not particularly limited, but the particle size is 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less. The amount of aluminum hydroxide powder added to the syrup is naturally determined by the depth, specific gravity, hardness, strength, heat resistance, price, etc. of the desired artificial marble product, but it is 80 to 40% based on the total amount of both. % by weight, preferably 75-50% by weight. If the amount of aluminum hydroxide powder added exceeds 80% by weight, the depth of the artificial marble product will be lost and properties such as strength will deteriorate, which is not preferable. If the amount added is less than 40% by weight, the properties of the artificial marble product such as hardness, heat resistance, and flame retardance will be inferior, and the slurry viscosity will be low, making it sticky and difficult to handle. This is not preferable because pressure may not be applied during polymerization and curing.

In the present invention, there are no particular limitations on the method of mixing each component. For example, to obtain syrup, an acrylonitrile-styrene copolymer resin can be added to a polymerizable monomer mainly composed of methyl methacrylate with stirring, and then dissolved by stirring vigorously while heating or cooling. However, the syrup and aluminum hydroxide powder can be mixed using a tank or kneader equipped with a stirrer.

Shaping under pressure and polymerization hardening as used in the present invention means shaping the mixed slurry of syrup and aluminum hydroxide powder obtained in the above explanation by pressurizing it in a mold, and at the same time forming methyl methacrylate. Curing is carried out by polymerizing a polymerizable monomer as a main component, and specifically, it can be carried out by compression molding, extrusion molding, transfer molding, etc., but is not limited to these methods. Note that the polymerization does not necessarily have to be completed in this step, and can be completed in a separate post-cure step if necessary.

The polymerization curing method according to the present invention is not particularly limited, and includes, for example, a heating method in the presence or absence of a radical polymerization initiator, a method using a so-called redox system comprising a radical polymerization initiator and an accelerator, and a method using ultraviolet rays or radiation. It can be carried out by any method such as irradiation, but is not limited thereto. Among these polymerization curing methods, particularly preferred is the method of adding a radical polymerization initiator and heating. Examples of radical polymerization initiators include 2.
Azo compounds such as 2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), diisopropyl peroxydicarbonate, dimethoxyisopropyl) peroxydicarbonate,
t-Butyl peroxyneodecanoate, lauroyl peroxide, benzoyl peroxide, 2,2-bis(t-
Examples include, but are not limited to, peroxides such as (butylperoxy)butane. Note that two or more types of radical polymerization initiators can also be used in combination. The amount of the radical polymerization initiator added is 0.005 to 3% by weight, preferably 0.01 to 1% by weight, based on the total amount of syrup. Pressurized heating conditions are usually 70 to 120 °C, preferably 80 to 110 °C under a pressure of 10 to 30 (1/~, preferably 50 to 200 KF!, / crA) for 0.3 to 30 minutes, preferably The post-cure is usually carried out at 100 to 140'C1, preferably 110 to 130C for 0.25 to 4 hours, preferably 5 to 3 hours at CL.

The slurry of the present invention may contain all or part of the polymerizable monomer composition mainly composed of methyl methacrylate and acrylonitrile as described above within a range that does not impair the characteristics of the artificial marble product. Polymers other than styrene copolymer resins, fillers other than aluminum hydroxide powder, dyes and pigments, reinforcing materials, modifying materials, stabilizers, mold release agents, lubricants, flame retardants, polymerization accelerators, polymerization modifiers, etc. It is also possible to add

(Examples) Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Examples 1 to 3 Acrylonitrile-styrene copolymer resin (Sevian N, 020SF, manufactured by Daicel Chemical Industries, Ltd.) in the amount shown in Table 1 was dissolved in methyl methacrylate and trimethylolpropane trimethacrylate in the amounts shown in Table 1. and got syrup. Aluminum hydroxide powder (Hisilite H-310, manufactured by Showa Light Metal Co., Ltd.) is added to this syrup 35 heavy portion.
65 parts by weight, and 0.35 and 0.2 parts of t-butylperoxypivalate and 2,2-bis(t-butylperoxy)butane, respectively, per 100 parts by weight of syrup.
BMC was obtained by adding 5 parts by weight and kneading with a kneader. All of the obtained BMGs had no stickiness and were easy to handle. This was press-molded using a mold with a mirror finish for 15 minutes at 100℃ with an effective pressure of 150Kg/CIA, and after releasing the mold, post-curing was performed for 2 hours in a hot air oven at 130℃ to form a flat plate (200sX 200sX 10mm>
I got it. All of the obtained flat plates had a beautiful appearance with excellent depth, and were measured with a fade-o-meter of 50
A 0-hour accelerated exposure test was conducted, but no yellowing was observed.

Separately, hold the plate surface of the flat plate vertically, and
A flame adjusted to a certain size was radiated perpendicularly to the plate surface from a gas burner installed at a distance of 0.degree. C., and the speed at which the plate was burned and its thickness decreased was measured.

The results are shown in Table 1. From this, the artificial marble of the present invention is
It can be seen that the burning speed of the flame is low and it is difficult for the flame to penetrate to the back side.

Comparative Example 1 Methacrylic resin (Parabeads HR1 Kyowa Gas Chemical Industry (
Co., Ltd.) into 35 parts by weight of syrup dissolved in a mixed solution consisting of 80 parts by weight of methyl methacrylate and 5 parts by weight of trimethylolpropane trimethacrylate,
65 parts by weight of the same aluminum hydroxide powder as in Examples 1 to 3, and t-butylperoxypivalate and 2,2-bis(t-butylperoxy)butane were added in amounts of 0.35 and 0, respectively, per 1100 parts by weight of cyano. .25 parts by weight were added and mixed to obtain a slurry. The slurry was poured into a mold assembled by sandwiching a U-shaped soft gasket between two glass plates, and the whole mold was placed in warm water at 60℃ for 5 minutes.
Then, it was held in a hot air oven at 130° C. for 2 hours to obtain an artificial marble cast plate with a thickness of 100M. Note that the slurry had fluidity when kept in hot water at 60°C for 2 hours, but
It had lost fluidity after being held for 4 hours.

The thickness reduction rate of this artificial marble board measured by the same method as Examples 1 to 3 was 1.60! It was rare at nl11/min.

Comparative Example 2 60 parts by weight of acrylonitrile-styrene copolymer resin,
An artificial marble board was obtained in the same manner as in Examples 1 to 3, except that 35 parts by weight of methyl methacrylate was used. In this comparative example, since the BMC was hard, the resulting board had poor filling, and it was not possible to obtain a board with a predetermined shape. In addition, yellowing was observed in a 500 hour accelerated exposure test conducted in the same manner as in Examples 1 to 3.

(Left below) Examples 4 to 8 Acrylonitrile-styrene copolymer resin (Denka AS,
A syrup was obtained by dissolving 40 parts by weight of AS-H-312 (manufactured by Denki Kagaku Kogyo Co., Ltd.) in a mixed solution of 55 parts by weight of methyl methacrylate and 5 parts by weight of 1,3-butylene glycol dimethacrylate.

Syrup in the amounts shown in Table 2, the same aluminum hydroxide powder as in Examples 1 to 3, and bis(4-1-butylcyclohexyl) peroxydicarbonate and 1,1-bis(t-
butylperoxy) 3,3,5-trimethylcyclohexane, respectively, at 0.0% per 100 parts by weight of syrup.
4 and 0.3 parts by weight were added and kneaded in a kneader to obtain BMC. All of the obtained BMGs were non-sticky and easy to handle. The artificial marble plates obtained by press-molding and post-curing this BMC under the same conditions as Examples 1 to 3 all have a beautiful appearance with an excellent sense of depth. No yellowing was observed in the 500 hour accelerated exposure test.

Comparative Example 3 An artificial marble board was press-molded in the same manner as in Examples 4 to 8, except that the mixing ratio of syrup and aluminum hydroxide powder was 65:35 by weight. In this comparative example, the slurry was sticky and difficult to handle, and because the slurry viscosity was low, the slurry turned into a lump and leaked from the fitting part of the mold, so the pressure was not maintained during molding, and the resulting flat plate Whitening spots and cloudiness were observed on the surface.

Comparative Example 4 An artificial marble board was obtained in the same manner as in Examples 4 to 8, except that the mixing ratio of syrup and aluminum hydroxide powder was 15:85 by weight.

In this comparative example, since the slurry was hard, the plate obtained by press molding had poor filling, and it was not possible to obtain a plate of the predetermined shape. Moreover, the artificial marble board of this comparative example had an opaque appearance with no sense of depth.

Example 9 Acrylonitrile-α-methylstyrene copolymer resin (L
A syrup was obtained by dissolving 35 parts by weight of uran KR2556U (manufactured by BASF) in a mixed solution of 60 parts by weight of methyl methacrylate and 5 parts by weight of ethylene glycol dimethacrylate. Example 1 for this syrup 35-fold finger part
65 parts by weight of the same aluminum hydroxide powder as in ~3, and t-butylperoxyneodecanoate and t-butylperoxyacetate were added at a ratio of 0.45 and 0.35 parts by weight, respectively, per 100 suspended parts of syrup. BMC was obtained by kneading with a kneader. The obtained BMC was not sticky and easy to handle. The artificial marble board obtained by press-molding and post-curing this BMC under the same conditions as Examples 1 to 3 has a beautiful appearance with excellent depth, and after 500 hours using the same method as Examples 1 to 3. No yellowing was observed in the accelerated exposure test.

Furthermore, the thickness of this artificial marble board was measured in the same manner as in Examples 1 to 3, and the rate of decrease was 1.09 m/min.

(Effects of the Invention) The present invention provides a polymerizable monomer molded product whose main component is methyl methacrylate filled with aluminum hydroxide powder, that is, an artificial marble product, by adding an acrylonitrile-styrene copolymer resin to the product. The purpose is to improve fireproofing performance, that is, resistance to flame penetration when exposed to fire, and to enable pressurized polymerization and curing to increase productivity.

The method of improving flame penetration resistance by adding the acrylonitrile-styrene copolymer resin of the present invention is more effective than the conventional method of increasing the thickness of the product or adding a large amount of flame retardant. Because it does not require heavy weight, it is possible to prevent a rise in material and transportation costs.Also, unlike flame retardants, acrylonitrile-styrene copolymer resin has various properties such as depth, strength, hardness, weather resistance, and corrosion resistance. Since the properties are not deteriorated, it has become possible to improve the flame penetration resistance while maintaining the excellent properties of acrylic artificial marble.

In addition, cast molding, which is a conventional and common manufacturing method for artificial marble products, is based on the low boiling point of the polymerizable monomer, which is mainly composed of methyl methacrylate, and because it is easy to inject into molds. Slurry has low viscosity and fluidity, and it is difficult to polymerize and cure under pressure to prevent boiling, so it must be polymerized at low temperatures and takes a long time to cure. It will require.

On the other hand, the method of the present invention uses 30 to 50% by weight of acrylonitrile-styrene copolymer resin based on the total amount of syrup, so the slurry has a high viscosity and can be cured by pressure polymerization, so methyl methacrylate is the main component. Polymerizable monomers can be polymerized at high temperatures by suppressing boiling,
This made it possible to cure quickly.

In addition, artificial marble products can be produced by injection molding or extrusion molding by filling aluminum hydroxide powder into a blend product of thermoplastic polymer, which is a polymerizable monomer mainly composed of methyl methacrylate, and acrylonitrile-styrene copolymer resin. The method for producing methyl methacrylate has very high productivity, but from the viewpoint of moldability, the molecular weight of the polymer whose main component is methyl methacrylate is low and it is thermoplastic.
The heat resistance and corrosion resistance are inevitably inferior to those according to the present invention.

Claims (1)

[Claims] (a) 30 to 50% by weight acrylonitrile-styrene copolymer resin based on the total amount of syrup;
(b) 20 to 60 parts by weight of syrup consisting of 0% by weight of a polymerizable monomer mainly composed of methyl methacrylate;
80 to 40 parts by weight of aluminum hydroxide powder in a total amount of 1
1. A method for producing artificial marble, which comprises mixing to a total weight of 0.00 parts by weight, shaping under pressure, and polymerizing and curing.