Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-11-04
2001-03-06
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S140000, C524S143000, C524S145000, C524S267000, C524S269000
Reexamination Certificate
active
06197857
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a polycarbonate resin composition. More specifically, it relates to a flame-retardant polycarbonate resin composition which has an excellent flame retardance and, an excellent moldability and an impact resistance, which exhibits an excellent appearance of a molding product and a sliding property and which is used in an office automation equipment and home electric appliances through injection molding, and to a molding product formed of this composition.
DESCRIPTION OF THE RELATED ART
As having the advantages of impact resistance, heat resistance and good electric properties, polycarbonate resins have many applications in various fields of, for example, office automation appliances, information and communication appliances, electric and electronic appliances, car parts and building materials. However, there are some problems with polycarbonate resins in that they require high molding and working temperatures and their melt fluidity is low.
On the other hand, moldings for parts and housings for office automation appliances such as duplicators and facsimiles and for other electric and electronic appliances such as those mentioned above shall have a complicated shape with local projections or depressions, for example, having ribs or bosses therewith, and are required to be lightweight and thin-walled from the viewpoint of resources saving. Therefore, desired are polycarbonate resin compositions having increased melt fluidity, or that is, having increased injection moldability.
On the other hand, compositions of polycarbonate resins to which are added styrene resins such as acrylonitrile-butadiene-styrene resins (ABS resins), acrylonitrile-styrene resins (AS resins) and the like are known as polymer alloys, and have many applications in the field of moldings as having good heat resistance and impact resistance. As a rule, polycarbonate resins are self-extinguishable. However, some of their applications to office automation appliances, electric and electronic appliances and others require high-level flame retardancy.
To meet the requirements as above, various methods have heretofore been proposed. Concretely, JP-A 61-55145 discloses a thermoplastic resin composition comprising (A) an aromatic polycarbonate resin, (B) an ABS resin, (C) an AS resin, (D) a halogen compound, (E) a phosphate, and (F) a polytetrafluoroethylene component. JP-A 2-32154 discloses a molding polycarbonate composition with high flame retardancy and high impact resistance, comprising (A) an aromatic polycarbonate resin, (B) an ABS resin, (C) an AS resin, (D) a phosphate, and (E) a polytetrafluoroethylene component.
Meanwhile, a polycarbonate resin is sometimes inferior to a nylon resin and a polyacetal resin in the sliding property and the abrasion resistance, and it cannot be used in sliding parts and bearings. In order to improve the sliding property of a polycarbonate resin molding product, a method of coating a grease or an oil has been so far employed. This method is however problematic in that the coating of a grease or an oil is needed, fine particles have adverse effects such as contamination of other parts and the sliding property changes over the course of time. For this reason, it has been required to improve the sliding property of the polycarbonate resin itself.
As a method of improving the sliding property of a polycarbonate resin, (1) there is generally a method in which a polycarbonate resin is blended with polytetrafluoroethylene. However, the melting point is high, the pulverization is required, and the cost is high. Accordingly, this compound is used in a small amount. When the amount thereof is increased, the surface of the molding product is sometimes worsened, and the sliding property is not necessarily improved. (2) In a method in which a polycarbonate resin is blended with a lubricant such as a polyethylene wax, a liquid paraffin, a higher fatty acid, a fatty acid amide or an ester of a fatty acid and an alcohol, the addition of a relatively large amount of the lubricant is required, and a problem of bleed-out sometimes occurs.
Further, (3) JP-A-60-144351 and JP-A-1-259059 disclose a method in which a polycarbonate resin is blended with ultrahigh-molecular-weight polyethylene having a viscosity average molecular weight of 1,000,000 or more singly or in combination with polytetrafluoroethylene. In this method, however, polyethylene is, in some cases, not melted, a dispersibility is poor, and a molding product has hardly a good surface. Still further, JP-A-9-279006 discloses a slidable resin composition comprising a polytetrafluoroethylene resin, a polyethylene resin having a viscosity average molecular weight of from 1,000 to 10,000, a flaky inorganic filler, a composite rubber graft copolymer and a flame retardant. These techniques use the polyethylene resin. However, either of polytetrafluoroethylene and ultrahigh-molecular-weight polyethylene resins is used, and problems derived from these resins still remain.
In addition, a composition containing a silicone compound has been known. For example, (4) JP-A-8-12868 discloses a thermoplastic resin composition obtained by blending. 100 parts by weight of a resin composition comprising (A) an aromatic polycarbonate, (B) an ABS resin and/or (C) an AS resin with (D) from 0.01 to 5 parts by weight of a fluororesin and/or a silicone and (E) from 1 to 40 parts by weight of a specific phosphate ester compound. Further, JP-A-8-295796 discloses a flame-retardant resin composition comprising (A) a thermoplastic resin containing from 99 to 5% by weight of a specific polycarbonate resin and from 1 to 95% by weight of the other resin such as ABS, (B) a phosphorus compound, (C) at least one type selected from a silicone, a fluororesin and a phenolic resin.
However, the silicones in these documents are identified to be the same type of the additive as the other fluororesin, and used for imparting the flame retardance. Besides, an oil having a number average molecular weight of from several hundreds to several millions, a gum, a varnish, a powder and pellets are only shown as the silicones. So long as the silicone oil is concerned, only a silicone oil having a viscosity of 30,000 cs is demonstrated in Examples.
Moreover, (5) JP-A-10-101920 discloses a resin composition comprising (A) from 30 to 90% by weight of a specific polycarbonate resin, (B) from 1 to 50% by weight of an ABS resin and (C) from 0.5 to 30% by weight of a substance selected from the group consisting of a low-molecular polyolefin, a silicone oil and silicone resin fine particles, and a slidable composition further comprising from 1 to 30% by weight of a phosphate ester compound. However, the silicones disclosed in these documents are silicone resin oils and silicone fine particles, and the use of optional silicones is only disclosed. Further, in Examples, silicone oils and silicone resin fine particles are demonstrated, and these are described to be substantially the same with respect to the effect of the sliding property.
SUMMARY OF THE INVENTION
It is an object of the invention to provide, under these circumstances, a flame-retardant polycarbonate resin composition in which when improving the sliding property in the molding of a thin and complicated polycarbonate resin molding product which is used in an office automation equipment, information and communication appliances, electric and electronic appliances, home electric appliances and automobiles, the appearance and the sliding property of the molding product being practically most important are both satisfied and a molding product using this composition.
In order to achieve the object of the invention, the present inventors have assiduously conducted investigations on the improvement of the sliding property of a flame-retardant polycarbonate resin composition obtained by blending a resin composed of a polycarbonate resin and a styrene resin and having a good flowability with a phosphate ester compound. Consequently, they have found that these problems can be solved by selective
Mitsuta Naoki
Nodera Akio
Takeuchi Noritada
Idemitsu Petrochemical Co. Ltd.
Moore Margaret G.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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