Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1999-03-25
2000-11-28
Gorr, Rachel
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525100, 525101, 525105, C08G 6391
Patent
active
061536946
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to graft copolymer particles which are prepared by using a coagglomerated rubber containing a silicone rubber, and a thermoplastic resin composition excellent in impact resistance, weather resistance, processability, thermal discoloration resistance and appearance of molded products.
BACKGROUND OF ART
Enhancement of impact resistance of a thermoplastic resin composition has been hitherto made widely by blending particles of a graft copolymer containing a rubber component with the thermoplastic resin.
As the rubber component, it is said that the use of a rubber component having glass transition temperature (Tg) of as low as possible is advantageous for exhibiting an impact resistance. In fact, a thermoplastic resin composition incorporated with a graft copolymer containing a polybutadiene rubber component having a low Tg of about -80.degree. C., for example, acrylonitrile/butadiene/styrene copolymer (ABS resin), is more excellent in impact resistance than a thermoplastic resin composition incorporated with a poly(butyl acrylate) rubber component having a Tg of about -50.degree. C.
In viewpoint of low Tg of rubber, Tg of a polyorganosiloxane (hereinafter also referred to as "silicone") rubber, for example, a polydimethylsiloxane rubber, is about -120.degree. C. and therefore it is expected to exhibit higher impact resistance, if graft copolymer particles containing a silicone rubber component can be employed, compared to those containing a polybutadiene rubber component.
Also, a silicone rubber is advantageous since a silicone rubber is more excellent in weather resistance than a poly(butyl acrylate) rubber and a polybutadiene rubber.
In view of these matter, recently it has been widely investigated to employ graft copolymer particles prepared from a silicone rubber or a composite rubber containing a silicone rubber.
For example, Japanese Unexamined Patent Publication No. 100812/1992 discloses the use of graft copolymer particles which are prepared by graft-polymerizing a vinyl monomer to a composite rubber having such a structure that a silicone rubber component and a poly(alkyl(meth)acrylate) rubber component are entangled so as not to be separated from each other.
Japanese Unexamined Patent Publication No. 239015/1992 discloses the use of graft copolymer particles which are prepared by graft-polymerizing a vinyl monomer to a composite rubber having such a structure that a silicone rubber component and a conjugated butadiene rubber component are entangled so as not to be separated from each other.
However, even in the case that graft copolymer particles containing the above-mentioned composite rubber is employed as an impact modifier, the effect for improving impact resistance of thermoplastic resins is still unsatisfactory, and a problem is to develop an impact modifier for exhibiting higher impact resistance especially at low temperature. Additionally, another problem is that a method for preparing the above-mentioned composite rubber requires a long time to obtain some kinds of composite rubbers having different silicone rubber content and is inferior in productivity.
DISCLOSURE OF INVENTION
It has been found that novel graft copolymer particles containing silicone rubber can be prepared and graft copolymer particles having varied silicone rubber contents can be easily prepared, by graft-polymerizing a vinyl monomer onto a coagglomerated rubber of enhanced particle size which is prepared by coagglomerating a mixed latex obtained by mixing a silicone rubber latex having a low Tg and excellent in mold releasing property with an acrylic rubber latex and/or a conjugated diene rubber latex, and that a thermoplastic resin composition wherein the above-mentioned graft copolymer particles are incorporated into a thermoplastic resin is not only extremely excellent in impact resistance but also excellent in weather resistance, processability, appearance of molded products.
Namely, the present invention relates to monomer to a coagglomerated rubber of enhanced p
REFERENCES:
patent: 5200465 (1993-04-01), Hellstern
patent: 5336720 (1994-08-01), Richards
Hamaguchi Shigeki
Hosoi Hideki
Miyatake Nobuo
Nakamori Daisuke
Takikawa Kazunori
Gorr Rachel
Kaneka Corporation
LandOfFree
Graft copolymer particles and thermoplastic resin compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Graft copolymer particles and thermoplastic resin compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Graft copolymer particles and thermoplastic resin compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1726660