Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-06-20
2001-11-13
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S198000, C525S09200D, C525S067000, C525S394000, C525S462000, C525S466000, C525S439000, C524S338000
Reexamination Certificate
active
06316579
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a thermoplastic resin composition which is useful as a material for office automation (OA) equipment, communication equipment, housings for household electric appliances, chassis, other shaped articles, automotive parts and so forth. More particularly, the invention relates to a thermoplastic resin composition and a flame-retardant resin composition, which comprise a polycarbonate-series resin and a styrenic-series resin as main components and are excellent in processability or moldability, external appearance properties, impact resistance and thermal stability.
BACKGROUND OF THE INVENTION
Polycarbonate-series resins have good dimensional stability, good mechanical characteristics and good thermal properties (heat resistance) and therefore are in wide industrial use (parts of electric or household electric appliances, precision instruments, OA equipment, medical instruments, household utensils, sports equipment, etc.). However, polycarbonate-series resins are poor in chemical resistance and processability (moldability, platability), in particular flow characteristics, besides being relatively expensive. Therefore, a number of polymer blends thereof with other thermoplastic resins have been developed. There is disclosed that, in Japanese Patent Publication No. 15225/1963 (JP-B-38-1525), Japanese Patent Publication No. 71/1964 (JP-B-39-71), Japanese Patent Publication No. 11496/1967 (JP-B-42-11496), and Japanese Patent Publication No. 11142/1976 (JP-B-51-11142), the moldability of polycarbonate resin can be improved and the thickness-dependency of impact strength is lowered by blending acrylonitrile-butadiene-styrene copolymers (ABS resins) or methyl methacrylate-butadiene-styrene copolymers (MBS resins) among thermoplastic resins with polycarbonate-series resins. For the purpose of flowability or fluidity improvement and cost reduction, such polymer blends are widely used in automotive, OA equipment, electronic and electric fields, among others.
However, polymer blends of a polycarbonate-series resin and a rubber-modified polystyrene resin such as an impact-resistant styrenic resin (high impact polystyrene) are poor in compatibility, mechanical characteristics, heat-stability and impact resistance, and therefore are of little present use.
In Japanese Patent Application Laid-Open No. 197554/1991 (JP-A-3-197554), there is disclosed that the compatibility of an aromatic polycarbonate-series resin with a polyphenylene ether resin can be enhanced by adding a compatibilizing agent and an elastomer component, hence the impact-strength of molded articles can be improved.
Moreover, in Japanese Patent Application Laid-Open No. 54160/1973 (JP-A-48-54160) and No. 107354/1974 (JP-A-49-107354), there is disclosed compositions of an aromatic polycarbonate and a polyester-series resin. These compositions are, however, poor in melt stability and its softening point lowers when the compositions are residence in molding process. In Japanese Patent Application Laid-Open No. 247248/1990 (JP-A-2-247248) and No. 100400/1997 (JP-A-9-100400), attempts at solving these problems have been made, but the effects are still unsatisfactory.
In Japanese Patent Application Laid-Open No. 131056/1987 (JP-A-62-131056), there is disclosed that the surface hardness can be improved by employing a composition of an aromatic polycarbonate and an acrylic resin, hence the abrasion resistance can be improved. The combination of these resins, however, is still poor in compatibility, and effects of improvement in abrasion resistance are not satisfactory.
On the other hand, in the fields of OA equipment and household electric appliances, among others, synthetic resin materials are required to have flame retardancy, and halogen-containing flame retardants, namely bromine- or chlorine-containing ones, are generally used as fire or flame retardants to be added externally. Such flame retardants can provide relatively high fire retardancy but tend to generate corroxive or toxic gases upon processing or combustion. In view of increasing interest in environmental problems in recent years, it is desired that flame-retardant resins free of chlorine- or bromine-containing halogen compounds be developed as means of solving the drawbacks mentioned above.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a thermoplastic resin composition which is excellent in moldability and useful for producing a molded article having a good external appearance and impact resistance by improving the compatibility of a polycarbonate-series resin with a diene-series block copolymer.
It is another object of the present invention to provide a thermoplastic resin composition which is comparable in flowability and impact resistance to polymer blends of a polycarbonate-series resin and an ABS resin in spite of its being a polymer blend comprising a polycarbonate-series resin, a diene-series block copolymer, and a thermoplastic resin (a rubber-modified styrene-series resin etc.) as main resin components.
Further object of the present invention is to provide a thermoplastic resin composition which is conducive to improvements in the quality of a polymer blend of a polycarbonate-series resin and a thermoplastic resin as main components, with high safety, non-corrosiveness (harmlessness), and high fire retardancy.
The present inventors pursued investigations intensively in order to achieve the above objects and, as a result, found that (i) a combination of a polycarbonate-series resin having a terminal hydroxy group with a diene-series block copolymer enhances the compatibility therebetween, and improves flowability and impact resistance of the resin composition, that (ii), in the combination of a polycarbonate-series resin, a diene-series block copolymer and a thermoplastic resin, the above-mentioned characteristics can considerably be improved and its flowability is excellent when compared to that of the polymer blend of the polycarbonate-series resin with an ABS resin, and that (iii) the fire retardancy and impact resistance can be markedly improved by the addition of a flame retardant such as an organophosphorus compound or a flame retardant auxiliary such as a fluorine-contained resin (fluororesin).
Thus, a thermoplastic resin composition of the present invention comprises (1) a polycarbonate-series resin of which the percentage of the terminal hydroxyl group is 1 mole % or above relative to the whole of the terminals, and (2) a diene-series block copolymer. The diene-series block copolymer comprises, in the same molecule, a polymer block (A) comprising mainly a vinyl aromatic compound and a polymer block (B) comprising mainly a conjugated diene compound. The diene-series block copolymer may be a block copolymer (C) comprising, in the same molecule, a polymer block (A) comprising mainly a vinyl aromatic compound and a polymer block (B) comprising mainly a conjugated diene compound; a hydrogenation product (D) of the block copolymer (C); an epoxy-modified or epoxy-introduced block copolymer (E) in which a double bond derived from the block copolymer (C) and/or a conjugated diene compound of the partial hydrogenation product (D) is epoxidized; or an acid-modified or acidic group-introduced block copolymer (F) of the block copolymer (C) and/or the hydrogenation product (D) thereof. The content of the diene-series block copolymer is about 0.1 to 30 parts by weight relative to 100 parts by weight of the polycarbonate-series resin.
Further, the thermoplastic resin composition may be composed of the second thermoplastic resin (3). As the second thermoplastic resin, there may be employed a polyester-series resin, a polyamide-series resin, an aromatic polyether-series resin, a rubber-modified polymer or rubber-containing polymer, a polysulfide-series resin, an acrylic resin, and a polyolefinic resin. The ratio of the polycarbonate-series resin (1) relative to the second thermoplastic resin (3) is about 1/99 to 99/1 (% by weight), and the content of the diene-series copolym
Ito Masaaki
Katayama Masahiro
Otsuka Yoshihiro
Asinossky Olga
Daicel Chemical Industries Ltd.
Seidleck James J.
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