Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-04-12
2002-07-09
Buttner, David J. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C525S067000, C525S09200D
Reexamination Certificate
active
06417257
ABSTRACT:
TECHNICAL FIELD TO WHICH THE INVENTION BELONGS
The present invention relates to a thermoplastic resin composition useful as the material for the housing, chassis or other members of office automation machines, communication apparatus or domestic electrical appliances or for automobile members. In particular, the present invention relates to a thermoplastic resin composition mainly comprising a polycarbonate resin and a polystyrene resin and having excellent processability, impact resistance and heat stability, and a flame-retardant resin composition based on the above thermoplastic resin composition.
PRIOR ART
Polycarbonate resins are widely used in industrial fields by virtue of their excellent mechanical characteristics and thermal properties. However, the resins having poor processability during molding, particularly flowability, so that many polyblends of polycarbonate resins with other thermoplastic resins have been developed. Among such polyblends, polyblends thereof with acrylonitrile-butadiene-styrene (ABS) resins have been widely used in the fields of automobiles and office automation machines, the electronic and electrical fields and so on, for the purposes of improving the flowability and lowing the cost. On the other hand, polyblends thereof with polystyrene are seldom used now because of their poor mechanical characteristics due to poor compatibility.
Meanwhile, the synthetic resin materials to be used in the fields of office automation machines, domestic electrical appliances and so on are further required to have excellent flame retardance, so that halogenated flame retardants (such as brominated or chlorinated ones) are frequently used as the external flame retardants for the materials. Such flame retardants have a disadvantage of generating corrosive or toxic gas during processing or burning, though they have relatively excellent in flame retarding effect. Under recent circumstances, where the interest in environmental problems has been increasing, as a means for overcoming this disadvantage, it has been expected to develop a flame-retardant resin without using a compound containing a halogen (such as bromine or chlorine).
DISCLOSURE OF THE INVENTION
The present invention aims at modifying a polyblend mainly comprising a polycarbonate resin and a polystyrene resin into a thermoplastic resin having a flowability and impact strength equivalent to those of a polyblend comprising a polycarbonate resin and an ABS resin, and at providing a harmless flame-retardant thermoplastic resin composition based on the resulting modified composition.
The inventors of the present invention have intensively studied to find that a resin composition prepared by combining a polycarbonate resin with a rubber-modified polystyrene resin and adding at least one member selected from the group consisting of (I) block copolymers (C), wherein both a polymeric block (A) mainly made from an aromatic vinyl compound and a polymeric block (B) mainly made from a conjugated diene compound are present in each molecule, and/or partially hydrogenated derivatives thereof (D), (II) epoxidized block copolymers (E) derived from the block copolymers (C) and/or the partially hydrogenated derivatives (D), epoxidized through the epoxidation of double bonds resulting from the conjugated diene compound, and (III) acid-modified block copolymers (F) derived from the block copolymers (C) and/or the partially hydrogentated derivatives (D) to the resulting combination is remarkably improved in compatibility and has an excellent flowability and impact strength and that a resin composition prepared by further adding an organophosphorus compound and a fluoroethylene polymer to the above resin composition is remarkably improved in flame retardance and impact resistance and is superior to polyblends of polycarbonate resins with acrylonitrile-butadiene-styrene (ABS) resins in flowability. The above longstanding problem has been solved by these findings to thereby accomplish the present invention.
The present invention relates to a thermoplastic resin composition comprising 100 parts by weight of a resin mixture comprising 30 to 95% by weight of a polycarbonate resin (a) and 5 to 70% by weight of a polystyrene resin (b), and 0.5 to 20 parts by weight of at least one member (c) selected from the group consisting of (I) block copolymers (C), wherein both a polymeric block (A) mainly made from an aromatic vinyl compound and a polymeric block (B) mainly made from a conjugated diene compound are present in each molecule, and/or partially hydrogenated derivatives thereof (D), (II) epoxidized block copolymers (E) derived from the block copolymers (C) and/or the partially hydrogenated derivatives (D), epoxidized through the epoxidation of double bonds resulting from the conjugated diene compound, and (III) acid-modified block copolymers (F) derived from the block copolymers (C) and/or the partially hydrogenated derivatives (D).
The present invention includes the following preferred embodiments. Namely, the present invention also relates to the above thermoplastic resin composition wherein the component (b) is a rubber-modified polystyrene resin satisfying the following requirements 1) to 3):
1) the content of rubber in the rubber-modified polystyrene resin is 15 to 25% by weight,
2) the volume mean particle diameter of rubber contained in the rubber-modified polystyrene resin is 0.3 to 5.0 &mgr;m, and
3) the gel content of the rubber-modified polystyrene resin is 15 to 70% by weight.
Further, the present invention relates to a thermoplastic resin composition as described above which comprises 10 to 94.9% by weight of the component (a), 5 to 70% by weight of the component (b) and 0.1 to 20% by weight of an aromatic polyester and in which the component (c) is at least one member selected from among the epoxidized block copolymers (II).
The above composition may. further contain 0.1 to 20 parts by weight of a polyalkylene terephthalate (d), 0.1 to 20 parts by weight of a polyphenylene ether resin (e), 1 to 40 parts by weight of an organophosphorus compound (f), 0.05 to 5 parts by weight of a fluoroethylene polymer (g) and/or 1 to 150 parts by weight of a flame retardant (i).
An embodiment according to the present invention provides a thermoplastic resin composition comprising 100 parts by weight of a resin mixture comprising 30 to 95% by weight of a polycarbonate resin (a) and 5 to 70% by weight of a rubber-modified polystyrene resin (b) satisfying the following requirements 1) to 3):
1) the content of rubber in the rubber-modified polystyrene resin is 15 to 25% by weight,
2) the volume mean particle diameter of rubber contained in the rubber-modified polystyrene resin is 0.3 to 5.0 &mgr;m, and
3) the gel content of the rubber-modified polystyrene resin is 15 to 70% by weight, 0.5 to 20 parts by weight of at least one member (c) selected from the group consisting of (I) block copolymers (C), wherein both a polymeric block (A) mainly made from an aromatic vinyl compound and a polymeric block (B) mainly made from a conjugated diene compound are present in each molecule, and/or partially hydrogenated derivatives thereof (D), (II) epoxidized block copolymers (E) derived from the block copolymers (C) and/or the partially hydrogenated derivatives (D), epoxidized through the epoxidation of double bonds resulting from the conjugated diene compound, and (III) acid-modified block copolymers (F) derived from the block copolymers (C) and/or the partially hydrogentated derivatives (D), and, if necessary, 0.1 to 20 parts by weight of a polyalkylene terephthalate (d) and/or 0.1 to 20 parts by weight of a polyphenylene ether resin (e).
Further, the present invention also provides a flame-retardant thermoplastic resin composition comprising the above thermoplastic resin composition, 1 to 40 parts by weight of an organophosphorus compound and, if necessary, 0.05 to 5 parts by weight of a fluoroethylene polymer.
The present invention will now be described in detail.
The term “polycarbonate resin” used in this description for the component (a) refers
Hamano Hiromitsu
Katayama Masahiro
Buttner David J.
Daicel Chemical Industries Ltd.
Flynn ,Thiel, Boutell & Tanis, P.C.
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