Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-10-05
2002-07-23
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...
C524S141000, C525S067000
Reexamination Certificate
active
06423766
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a flame-retardant polycarbonate resin composition and to electrical and electronic components of housings of office automation equipment, housings of electrical and electronic appliances and battery packs as made by molding the composition. More precisely, it relates to a flame-retardant, non-bromine polycarbonate resin composition having good flame retardancy, good mechanical properties including impact resistance, good flowability and good moldability, and to housings of office automation equipment, housings of electrical and electronic appliances and battery packs as made by molding the composition.
BACKGROUND OF THE INVENTION
As having good mechanical properties (especially high impact resistance), good electric properties, and good transparency, polycarbonate resins are widely used as engineering plastics in various fields of office automation equipment, electrical and electronic appliances, building materials, etc.
Among various thermoplastic resins, polycarbonate resins have a high oxygen index and are generally self-extinguishable. However, especially in the fields of office automation equipment and electrical and electronic appliances, concretely for applications to housings of office automation equipment, to housings of electrical and electronic instruments such as notebook-type personal computers and others, and to battery packs, resin compositions with much more improved flame retardancy are desired to satisfy the requirement for safety operation of those equipment and appliances.
For making resins have flame retardancy, heretofore, flame retardants comprising a bromine compound have been used. One problem with resin compositions that comprise such a bromine-containing flame retardant is that molds used for repeatedly molding the resin compositions are rusted and that the resin compositions being molded are yellowed while in molds. Another problem is that the resin compositions being molded release corrosive gases that may pollute the environment. In that situation, non-bromine flame retardants are being much desired for resin compositions.
On the other hand, office automation equipment and electrical and electronic appliances, concretely, their housings and battery packs are required to have much improved impact resistance. In order to improve the impact resistance of such equipment and appliances, concretely their components, one popular means that has heretofore been generally employed is to add rubbery improvers to polycarbonate resins and to mold the resulting resin compositions. However, this is problematic in that the resin compositions to which is added a large amount of such an impact resistance improver could not have good flame retardancy. For their applications, in particular, battery packs are used for mobile communication appliances such as portable telephones and others or for portable terminals such as notebook-type personal computers and others, and are therefore required to be lightweight and thin-walled. Accordingly, the materials for such battery packs are required to have good moldability and flowability.
Various techniques for those requirements have heretofore been proposed, for example, in JP-A 07-173401, 08-259792, 08-120169, 07-304943, 08-239565, etc. The compositions proposed therein could have flame retardancy in some degree, but are still problematic in that they contain bromine-containing flame retardants, or if not containing bromine-containing flame retardants, their mechanical properties such as impact resistance and also their moldability and flowability are poor.
The object of the invention is to provide a polycarbonate resin composition having improved mechanical properties such as impact resistance, having good moldability and flowability and having good flame retardancy even though not containing a bromine compound, and to provide housings of office automation equipment, housings of electrical and electronic appliances and also battery packs as made by molding the composition.
DISCLOSURE OF THE INVENTION
Given that situation, we, the present inventors have assiduously studied, and, as a result, have found that the object can be attained by adding a composite rubbery graft copolymer to a polycarbonate resin, preferably by adding a specific composite rubbery graft copolymer, a halogen-free phosphoric ester and a polytetrafluoroethylene thereto in a specific ratio of the composite rubbery graft copolymer to the halogen-free phosphoric ester.
The invention has been completed on the basis of these findings.
Specifically, the invention provides a polycarbonate resin composition, and housings of office automation equipment, housings of electrical and electronic appliances, and battery packs as made by molding the composition, which are as follows:
(1) A flame-retardant polycarbonate resin composition comprising (A) a polycarbonate resin and (B) a composite rubbery graft copolymer in a ratio by weight, (A):(B), falling between 99:1 and 90:10, and containing, relative to 100 parts by weight of the sum total of the component (A) and the component (B), (C) from 0.3 to 1.2 Darts by weight. in terms of phosphorus. of a halogen-free phosphoric ester, and (D) from 0.01 to 1.0 part by weight of a polytetrafluoroethylene, in which the ratio by weight of the amount of the composite rubbery graft copolymer (B) to the phosphorus content of the halogen-free phosphoric ester (C) falls between 2 and 15.
(2) The flame-retardant polycarbonate resin composition of (1), wherein the composite rubbery graft copolymer (B) is prepared by grafting a composite rubber, which has a structure composed of from 1 to 99% by weight of a polyorganosiloxane rubber component and from 1 to 99% by weight of a polyalkyl acrylate rubber components, the two components being so intertwisted with each other as not to separate from each other, and has a mean particle diameter of from 0.01 &mgr;m to 0.6 &mgr;m, with one or more vinyl monomers.
(3) Electrical and electronic components as made by molding the flame-retardant polycarbonate resin composition of (1) or (2).
(4) Housings of office automation equipment, or housings of electrical and electronic appliances, as made by molding the flame-retardant polycarbonate resin composition of (1) or (2).
(5) Battery packs as made by molding the flame-retardant polycarbonate resin composition of (1) or (2).
BEST MODES OF CARRYING OUT THE INVENTION
The invention is described in detail hereinunder.
1. Flame-Retardant Polycarbonate Resin Composition
(1) Description of Constituent Components
[i] Polycarbonate Resin (Component (A))
In the flame-retardant polycarbonate resin composition of the invention, the polycarbonate resin for the component (A) may be any and every one that may be prepared in any ordinary method of, for example, reacting a diphenol with a polycarbonate precursor such as phosgene, carbonate compounds, etc. Concretely, it includes polycarbonate resins as prepared through reaction of a diphenol with a carbonate precursor such as phosgene or transesterification of a diphenol with a carbonate precursor such as diphenyl carbonate, in a solvent of methylene chloride or the like in the presence of a known acid acceptor and a known molecular weight-controlling agent, to which is optionally added a branching agent.
For the reaction, various diphenols are employable. Especially preferred is 2,2-bis (4-hydroxyphenyl)propane (this is generally referred to as bisphenol A). As other bisphenols employable herein in addition to bisphenol A, mentioned are bis (hydroxyaryl) alkanes such as bis (4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 2,2-bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-1-methylphenyl)propane, bis(4-hydroxyphenyl)naphthylmethane, 1,1-bis(4-hydroxy-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3,5-tetramethylphenyl)propane, etc.; bis(hydroxyaryl)cycloalkanes such as 1,1-bis (4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,5,5-trimethylcycloh
Buttner David J.
Idemitsu Petrochemical Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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