JPS5991111A - Methacrylate polymer article and its production - Google Patents

Abstract

PURPOSE:To produce continuously a lightweight methacrylate polymer article having high fire resistance and a translucent beautiful appaerance, by extruding a mixture of a methacrylate-based polymerizable syrup and an inorganic filler. CONSTITUTION:A mixture is formed from a methacrylate-based polymerizable syrup containing 10-40wt% methacrylate polymer (e.g., methyl methacrylate homopolymer or its copolymer with an alpha,beta-ethylenically unsaturated compound), an inorganic filler (e.g., ettringite), a small amount of a thermosetting catalyst as a polymerization catalyst for the above syrup, and a photosensitizer. The titled article is obtained by extruding the mixture by an extruder, casting the surface of the extrudate by irradiation with light just after the extrusion and then curing the extrudate by polymerization. The obtained product is a polymer article comprising the methacrylate polymer, 20-80wt%, based on the total weight of the mixture, inorganic filler, the thermosetting catalyst, and the photosensitizer.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a method for producing a methacrylate polymer article by extrusion molding a mixture of a polymerizable silica mainly composed of methacrylate and an inorganic filler, and a methacrylate polymer of the molded article. [Background technology related to articles] Manufacturing a hardened molded product with high translucency and an astronomical stone appearance by adding an inorganic filler to methyl methacrylate (MMA) requires a large amount of, for example, silica sand, calcined alumina, hydrated alumina, etc. This is done industrially by blending.

A curing agent is mixed with a mixture of polymerizable silica mainly composed of methyl methacrylate (MMA) and an inorganic filler,
The method of pouring into a suitable mold and curing it is often used in construction materials for the production of so-called artificial marble, but it is also difficult to use the batch method for producing plate materials of a certain size or molded products with uneven patterns. Manufacturing was limited, and continuous molding was not possible.

On the other hand, it is generally possible to mix an inorganic filler with methyl methacrylate polymer and extrude it, but in this case, there is a lot of wear and tear on screws and barrels because they are melt-kneaded in a molding machine, and it is difficult to melt and knead the polymer. Due to the high temperature, inorganic fillers that are effective in imparting fire resistance, such as aluminum hydroxide and ettringite, cannot be used.

It goes without saying that crosslinked polymers cannot be extruded.

[Purpose of the invention]

The present invention eliminates the above-mentioned drawbacks and inconveniences, and makes it possible to continuously produce a cured product of methacrylate polymer using the above-mentioned inorganic filler, which cannot generally be extruded. The present invention provides a method for producing a methacrylate polymer article that is highly fire resistant, has a beautiful translucent appearance, and is lightweight.

[Disclosure of the invention]

As a result of intensive research in order to solve the above-mentioned drawbacks and inconveniences, the inventors of the present invention have continuously extruded and molded a mixture of a polymerizable sill whose main component is methacrylate and an inorganic filler. A molding method for producing polymeric articles has been discovered.

The present invention will be explained in detail below.

In the present invention, the resin composition is a methacrylate polymer containing 10 to 40% of a methacrylate polymer selected from a homopolymer of methyl methacrylate or a copolymer of methacrylate and an α,β-ethylenically unsaturated compound. polymerizable syrup (syrup containing 10-40% by weight of methacrylate polymer dissolved in methacrylate monomer), 20-80% by weight of mineral filler and a small amount, preferably 0.2-10% by weight of mineral filler. % by weight of a silica catalyst as a polymerization initiator, i.e. a thermosetting catalyst and a photosensitizer, and a resin composition whose effective structure is a powder of a polymer of methacrylate such as polymethyl methacrylate (PMMA). It is. This manufacturing method involves extruding and molding this mixture using an extrusion molding machine.

First the polymerizable syrup of methacrylate and the mineral filler are premixed and a small amount, preferably 0.2 to 10
% by weight of a silica catalyst as a polymerization initiator, i.e., a thermosetting catalyst and a photosensitizer, and then a powder of a methacrylate polymer such as polymethyl methacrylate (PMMA) is mixed to form the mixture. A dough is formed, this dough is extruded and shaped using an extrusion molding machine at approximately room temperature, and immediately after extrusion, the surface is hardened by irradiation with light, and then heated and continuously polymerized and hardened to form methacrylate. In the present invention, which is a molding method for manufacturing polymer articles, the photosensitizer is mixed by irradiating the surface with light such as ultraviolet rays immediately after extruding it in an extrusion molding machine, and then heating it. Makes molding easier during continuous polymerization and curing molding,
Moreover, it makes the surface of the cured product smooth.

In the present invention, methacrylate polymer powder (
The powder) dissolves (swells) in the monomer methacrylate to increase the viscosity of the mixture so that it can be easily shaped during extrusion molding.

In the present invention, the methacrylate monomers include methyl methacrylate ethyl methacrylate probyl methacrylate butyl methacrylate ethyl acrylate butyl acrylate 2-ethylhexyl acrylate ethylene glycol dimethacrylate trimethylolpropane trimethacrylate hydroxypropyl methacrylate hydroxyethyl acrylate dimethylaminoethyl methacrylate Examples include diethylamine ethyl meccrylate.

And, as an inorganic filler, ettringite (3CaO・Aj! 0・3CaS0・28-31
1 O) Aluminum hydroxide (alumina hydrate), silica sand, borax, alumina, talc, kaolin, calcium carbonate, etc., and may be used alone or in combination. This inorganic filler does not need to be completely dry, and the moisture adhering to the surface does not pose a particular problem in obtaining a cured product, and the amount of water is 0.1 to 3% of the filler. % is acceptable. Ettringite used as an inorganic filler is 20
If it is less than 80% by weight, the fire resistance is poor, and if it is more than 80% by weight, sufficient mechanical strength cannot be obtained. Glass fiber, synthetic fiber (vinylon, nylon, etc.), glass cloth, paper, or silk cloth may be used as necessary.

As a thermosetting catalyst, the Shirabu catalyst as a polymerization initiator has an active oxygen content of 1.16 to 12.4%, and a half-life temperature of 185°C or less in 1 minute and 16% in 10 hours.
Organic peroxides having a temperature of 0° C. or lower are preferable, such as 2,4-dichlorohebuyl peroxide, 0-methylbenzoyl peroxide, lauroyl peroxide, benzoyl peroxide, P-chlorobenzoyl peroxide, etc.)? Silver oxide dicumyl peroxide 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexane 3-bis-(tert-butylperoxy-isopropyl)-benzene tert-butylcumyl peroxide 1 -G (
tert-butylperoxy-3,3,5-trimethyl)-cyclohexane 1-di(tert-butylperoxy)-cyclohexane 2,2-di(tert-butylperoxy)-butane 4,4-di(tert-butylperoxy)-cyclohexane -Butylperoxyvaleric acid-n-butyl ester and other peroxyketals tert-butylperoxy-2-ethylhexanoate tert-butylperoxy-hexahydroterephthalate tert-butylperoxyazelade tert
-Butyl peroxy-3, 5, 5-trimethylhexoate tert-butyl peroxyacetate tert-butyl peroxymalate tert-butyl peroxybenzoate bis(4-tert-butyl, cyclohexyl) peroxyketobate Examples include percarbonates such as tert-butylperoxyisopropyl carbonate, and are selected from among these.

And, as a photosensitizer, for example, benzoin benzoin methyl ether benzoin ethyl ether benzoin isopropyl ether benzophenone anthraquinone etc.

A resin mixture composition of a polymerizable syrup of methacrylate as described above, an inorganic filler of 20 to 80% by weight based on the total amount of the mixture, a catalyst for syrup as a polymerization initiator, and a powdered methacrylate polymer. Immediately after being thoroughly kneaded in a □ mixer such as a roll or kneader, and put into an extrusion molding machine, the surface layer of the shaped molded product is hardened by irradiation with ultraviolet rays from a high-pressure mercury lamp, and then It is heated and cured through an induction heating device to obtain the desired cured methacrylate polymer.

As described above, according to the present invention, compared to conventional batch-type discontinuous operations, there is no need to shut off air (continuous operation is possible, and production efficiency is greatly improved).

All kinds of polymeric articles can be formed using the methacrylate polymer mixtures of this invention. Therefore,
The mixture can be molded alone or coated with a core material, and can be used as a laminate to wood or other plastics.

Next, examples and comparative examples will be explained.

(Example) 85 parts of methyl methacrylate, 10 parts of ethyl acrylate
30 parts by weight of methyl methacrylate polymerizable silica containing 30% of a methacrylate polymer consisting of 5 parts of dimethylaminoethyl methacrylate in the monomer, 65 parts by weight of ettringite, 0 parts by weight of benzoin isopropyl ether
．． 3 parts by weight were mixed in a Nigu at room temperature, and then 2% by weight of bis(4-te) was added to the methacrylate polymerizable sill.
After adding rt-butylcyclohexyl) peroxyla carbonate and mixing well, 4.5 parts of powdered methyl methacrylate polymer and 0.2 parts of stearic acid are added and kneaded until a dough is formed. This mixture was then mixed with 3
It was extruded into a plate shape using a single screw extruder (No. 01). In this case, extrusion molding was carried out at a cylinder temperature of 25° C. to 30° C., and a die temperature of 55° C..

This extruded molded body was irradiated with ultraviolet rays for 30 seconds in an 80 W mercury lamp irradiation tank to cure the surface, and then continuously heated and cured at 75° C. using an electromagnetic induction heating device. This cured product formed by heat curing yielded a hard molded product with a smooth surface. The obtained cured product had self-extinguishing properties against flames and was translucent to light.

(Comparative Example) In the above example, ultraviolet irradiation was omitted, but the surface curing of the excipient was inhibited and the object became sticky. [Effects of the Invention] As described above, the methacrylate polymer article of the present invention 20~ based on the total amount of methacrylate polymer and mixture
Since it is composed of 80% by weight of an inorganic filler, it has high fire resistance, a beautiful translucent appearance, and is lightweight, making it useful as a construction material as so-called artificial marble.

Moreover, since the manufacturing method can be extruded at room temperature, effective inorganic fillers such as aluminum hydroxide and ettringite can be used to impart fire resistance. Highly fire resistant.

The present invention enables continuous molding of methacrylate polymer articles that have a beautiful translucent appearance and are lightweight, and are useful as construction materials such as so-called artificial marble. Compared to other operations, there is no need to shut off the air, and continuous operation is possible, greatly improving manufacturing efficiency.

Claims (1)

[Claims] l) A methacrylate polymer comprising 20 to 80% by weight of an inorganic filler and a small amount of a thermosetting catalyst as a polymerization catalyst and a photosensitizer, based on the total amount of the methacrylate polymer and the mixture. Combined goods. 2) The methacrylate polymer article according to claim 1, wherein the inorganic filler is ettringite. 3) The methacrylate polymer article of claim 1, wherein the inorganic filler is primarily ettringite. 4) A polymerizable silica whose main component is methacrylate, an inorganic filler, a small amount of a thermosetting catalyst as a polymerization catalyst for the silica, and a photosensitizer are mixed, and the mixture is extruded and shaped using an extrusion molding machine. , characterized by being formed by irradiating light to harden the surface immediately after extrusion and then heating to polymerize and harden molding, and inorganic filling of 20 to 80% by weight based on the total amount of methacrylate polymer and mixture. A method for producing a methacrylate polymer article comprising a thermosetting catalyst as a polymerization catalyst and a photosensitizer in small amounts.