Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1990-08-09
1992-08-04
Michl, Paul R.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524806, 524837, 526279, 428447, C08F29908
Patent
active
051359812
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for the production of methacrylic resin molded items, more particularly to a method for the production of methacrylic resin molded items having excellent mar resistance, weather resistance and heat resistance.
BACKGROUND ART
Presently, various synthetic resin molded items are on the market. Among them, (meth)acrylic type resins are used in a wide range of fields regardless of whether they are used outdoors or indoors, such as glazing, covers for lights, ornaments and the like because they have a beautiful external appearance and excellent transparency. However, (meth)acrylic type resins not only have poorer heat resistance than inorganic glass but also have defects in their mar resistance, and if these points are improved, further development of a number of applications will be expected. Accordingly, various methods for the improvement of such defects have hitherto been investigated and proposed.
(1) Prior Arts Relative to Improvement of Mar Resistance
There have been adopted various methods such as a method in which a mar resistant film-forming material is coated by a spraying method, a dipping method or the like on a surface of a molded item obtained from a synthetic molding material by any desired means and thereafter the coated film is polymerized and solidified with electron beams or heat to form a mar resistant film; a method in which a molded item is irradiated with ultraviolet rays in advance and thereafter a mar resistant film is formed; or a method in which a mar resistant film forming material such as a polyfunctional acrylate coated on a mold is prepolymerized and thereafter a basic resin material is poured and polymerized (cf. Japanese Patent Publication (Kokoku) Nos. Sho 53-9876, Sho 54-14617, and Sho 54-14618). However, these methods have problems such as insufficient adhesion between the base resin material and the mar resistant film, and complication of steps.
(2) Prior Arts Relative to Improvement of Heat Resistance
Various methods have been proposed with a view to increasing the heat resistance of the methacrylic type resins. As one of them, there has been proposed a method in which an alkyl methacrylate monomer or syrup is partially crosslink-polymerized to form a gel-like polymer, and a molded item is produced using the gel-like polymer (cf. Japanese Patent Publication (Kokai) No. Sho 60-202128). According to this method, crosslinked molded items having excellent transparency and heat resistance can be obtained but the molded items are crosslinked and thus have a low adhesion with the mar resistant film, resulting in that upon forming a mar resistant film on the surface of the molded item, it is necessary to increase adhesion of the surface of the molded item with the film by conducting a cumbersome pretreatment such as solvent treatment or irradiation of ultraviolet rays. As a solution therefor, the present inventors have proposed a method in which an acrylic mar resistant layer is provided at the same time as the molding (cf. Japanese Patent Publication (Kokai) No. Sho 62-20513). According to this method, adhesion between the film and the surface of the molded item is increased but there arises a problem that the mar resistance decreases upon exposure to ultraviolet rays.
Therefore, it is a main object of the present invention to provide a method for producing easily and at low cost methacrylic type resin molded items which have high mar resistance and high heat resistance and which are excellent in adhesion between the mar resistant film and the base resin material.
DISCLOSURE OF INVENTION
According to the present invention, a method for the production of methacrylic type resin molded items is provided, which method is characterized by:
contacting
(A) a preliminary reaction product obtained by polymerizing a composition composed of a hydrolyzate of an alkoxysilane having a (meth)acryloxy group and silica gel to a reaction ratio of 15 to 60, with
(B) a base molding material composed of a (meth)acrylic type partial
REFERENCES:
patent: 3986997 (1976-10-01), Clark
patent: 4324712 (1982-04-01), Vaughn, Jr.
patent: 4324839 (1982-04-01), Frye
patent: 4442168 (1984-04-01), White et al.
patent: 4830803 (1989-05-01), Matsumara et al.
Matsumaru Shigeo
Mochizuki Akihiro
Soma Ichiro
Kuraray Co. Ltd.
McDonald, Jr. J.
Michl Paul R.
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