Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-11-20
2003-07-29
Woodward, Ana (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S074000, C525S282000, C525S285000, C525S313000
Reexamination Certificate
active
06599978
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a maleimide-based and/or an unsaturated dicarboxylic acid anhydride-based copolymer excellent in heat resistance, transparency, mechanical strength and moldability, unlikely to thermal degradation, small in an extent of coloration and deterioration occurring in the process of molding, and superior in appearance after molding, a thermoplastic resin composition comprising said copolymer and a rubbery polymer, and processes for producing said copolymer and said thermoplastic resin composition.
BACKGROUND ART
Recently, in the fields of electric instruments and automobile industry, there has been a tendency of attaching importance to a design property, and materials used in these fields have been required to have a high mechanical performance, a light weight and an excellent appearance for such a tendency. In order to satisfy such a requirement, polycarbonate-based resins and polyphenylene ether-based resins, both of which belong to a material field called engineering plastics, has been used, and SMI resin, namely a copolymer of styrene and N-phenylmaleimide, has been developed and used. Although these resins are superior in heat resistance, they are inferior in moldability. Currently, the shape of resin articles is becoming more complicated to satisfy the desire for a design property and their wall thickness is becoming smaller to satisfy the desire for lessening the weight. Under such a condition, an easiness of handling at the time of molding has been paid an attention to as one of the material performances also from an aspect of improving the product yield and saving energy and resources. For such a viewpoint, a resin material superior in moldability and having a heat resistance comparable to that of engineering plastics has been required.
In order to improve a heat resistance of thermoplastic resins, a resin composition prepared by blending a rubber-reinforced resin with an &agr;- methylstyrene-based copolymer using &agr;-methylstyrene as a component for the copolymer is used. In this case, an inclusion of &agr;-methylstyrene as a component of a resin matrix contributes to a heat resistance. Accordingly, this material has a fault that no sufficient heat resistance can be realized when the content of &agr;-methylstyrene is low, while thermal degradation readily takes place in the process of molding when the content of &agr;-methylstyrene is high.
With the aim of overcoming the above-mentioned fault of &agr;-methylstyrene-based resins, a method of using heat resistant resins comprising a maleimide-based copolymer or an unsaturated dicarboxylic acid anhydride-based copolymer has been proposed in JP-A 61-16955, etc. Further, JP-A-3-205411 has proposed a technique of producing such a maleimide-based copolymer or unsaturated dicarboxylic acid anhydride-based copolymer by the method of continuous solution copolymerization which is said to be desirable from the viewpoint of making uniform a comonomer distribution in the copolymer.
However, the above-mentioned maleimide-based copolymer and unsaturated dicarboxylic acid anhydride-based copolymer contain unreacted unsaturated dicarboxylic acid anhydride-based monomer or unreacted maleimide-based monomer etc., and these unreacted monomers are quite difficult to remove.
In case the unreacted monomers such as unsaturated dicarboxylic acid anhydride-based monomer, maleimide-based monomer or the like remain in the resin in a large quantity, there arises a problem that the resin becomes colored at the time of molding. Further, there is a problem that the unreacted monomers vaporize and exhale to form a silver streak on a surface of molded article to deteriorate an appearance of molded article. Further, there is a problem that the vaporized components of the unreacted monomers are deposited on a mold and contaminates the molded article as a soil to deteriorate an appearance of molded article. Although an operation of beforehand removing of volatile components such as water are generally conducted by subjecting a resin to a preliminary drying prior to molding, it is quite difficult to remove the unreacted monomers by such an operation.
Accordingly, a lowness of the content of unreacted monomers in a resin is very important to the molding work.
It is an object of the present invention to obtain a maleimide-based and/or unsaturated dicarboxylic acid anhydride-based copolymer which is low in the content of unreacted monomer such as a maleimide-based monomer, unsaturated dicarboxylic acid anhydride-based monomer and the like, superior in heat resistance, transparency, mechanical strength and moldability, unlikely to thermal degradation, small in an extent of coloration and deterioration occurring in the process of molding, and excellent in appearance after molding; and a thermoplastic resin composition comprising said copolymer.
DISCLOSURE OF THE INVENTION
The essentiality of the present invention consists in:
(1) a copolymer comprising a maleimide-based monomer unit and/or an unsaturated dicarboxylic acid anhydride-based monomer unit as constitutional components, wherein said copolymer contains an unreacted maleimide-based monomer and/or an unreacted unsaturated dicarboxylic acid anhydride-based monomer in an amount of 200 ppm or less and an adduct of a compound other than the constitutional components of said copolymer and said maleimide-based monomer and/or said unsaturated dicarboxylic acid anhydride-based monomer in an amount of 0.1 to 3,000 ppm;
(2) a thermoplastic resin composition comprising, as constitutional components, (A) 20-90 parts by weight of a maleimide-based copolymer comprising (a) 15-65% by weight of a maleimide-based monomer unit and (b) 85-35% by weight of at least one monomer unit selected from the group consisting of an aromatic vinyl-based monomer and other vinyl-based monomer (the total amount of the monomer units (a) and (b) is 100% by weight), (B) 80-10 parts by weight of a graft polymer obtained by polymerizing at least one monomer selected from the group consisting of an aromatic vinyl-based monomer and other vinyl-based monomer in the presence of a rubbery polymer, and (C) 0-100 parts by weight of other thermoplastic resin, wherein said thermoploastic resin composition contains unreacted maleimide-based monomer in an amount of 10 ppm or less, a volatile component other than said maleimide-based monomer in an amount of 0.5% by weight or less as a total volatile amount, and an adduct of a compound other than the constitutional components of said maleimide-based copolymer and said maleimide-based monomer in an amount of 0.1 to 3,000 ppm;
(3) a process for producing a copolymer comprising, as constitutional components, a maleimide-based monomer unit and/or an unsaturated dicarboxylic acid anhydride-based monomer unit which comprises adding a compound other than the constitutional components of said copolymer before, during or after polymerizing a monomer mixture comprising the maleimide-based monomer and/or the unsaturated dicarboxylic acid anhydride-based monomer, or to a copolymer comprising said monomer units as constitutional components obtained by the polymerization; and
(4) a process for producing a thermoplastic resin composition which comprises polymerizing a monomer mixture comprising a maleimide-based monomer, an aromatic vinyl-based monomer and/or other vinyl-based monomer to form a maleimide-based copolymer comprising these monomer units as constitutional components, and then adding to the resulting maleimide-based copolymer a compound other than the constitutional components of said maleimide-based copolymer, said graft copolymer, and optionally other thermoplastic resin.
BEST MODE FOR CARRYING OUT THE INVENTION
As the maleimide-based monomer which can be used for the production of the maleimide-based copolymer of the present invention, maleimide, N-methylmaleimide, N-ethylmaleimide, N-(n-propyl)-maleimide, N-isopropylmaleimide, N-t-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-toluylmaleimide, N-xylylmaleimide, N-naphthylmaleimide and the like ca
Shikisai Yoshifumi
Yokohama Hisaya
Mitsubishi Rayon Co. Ltd.
Woodward Ana
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