Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-03-01
2001-07-17
Woodward, Ana (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C525S133000
Reexamination Certificate
active
06262166
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to novel polymer blend compositions which are excellent in fluidity, heat resistance and mechanical characteristics.
2. Background Art
Thermoplastic resins having well-balanced fluidity, heat resistance and mechanical characteristics are generally needed for industrial purposes.
For example, polyphenylene ether resins are excellent in mechanical characteristics, electrical properties, acid-resistance, alkali-resistance, heat resistance, etc. and have low water absorbing capacity and high dimensional stability. Because of having these properties, polyphenylene ether resins have been widely employed as, for example, housing chassis materials in electrical apparatuses and office automation (OA) instruments such as computers and word processors. Moreover, it is frequently required that these materials be flame retarding from the viewpoint of fire prevention. With the recent remarkable progress in the technology, OA instruments have become more and more small-scaled and lightweight with improved functions. Thus, these materials are frequently molded into thin-walled articles. Therefore, it has been desired to further improve the fluidity (molding proccessability) of these resin materials.
Because of its poor fluidity, polyphenylene ether is generally employed in the form of polymer blends with polystyrene, as suggested by JP-B-43-17812 (the term “JP-B” as used herein means an “examined Japanese patent publication”) and U.S. Pat. No. 3,383,435. Polyphenylene and polystyrene are compatible with each other completely at an arbitrary ratio. As the polystyrene content increases, the fluidity is improved but the heat resistance is lowered. Although JP-B-48-40046 discloses mixtures of a polyphenylene ether with a styrene/acrylonitrile copolymer containing from 3 to 18% by weight of the acrylonitrile component, these compositions are not necessarily satisfactory in the balance of heat resistance, fluidity and mechanical characteristics.
Further, JP-A-6-306254 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses a technique for improving the balance of heat resistance and fluidity by using an acrylonitrile/styrene resin containing a specific amount of acrylonitrile. However, this technique suffers from a problem that peeling phenomenon of the resin is not sufficiently controlled and has a poor practical strength.
Furthermore, JP-A-9-31321 discloses a technique for improving the fluidity of a resin composition by blending a polyphenylene ether, a polystyrene and/or rubber-modified polystyrene with a styrene/acrylonitrile copolymer having an acrylonitrile content of from 7 to 11% by weight and a melt flow rate of from 5 to 100 g/10 min. Although the fluidity can be improved thereby, the impact strength and heat distortion temperature are lowered with a decrease in the molding temperature.
SUMMARY OF THE INVENTION
An object of the present invention is to provide novel polymer blend compositions which are excellent in their balance of fluidity, heat resistance, mechanical characteristics, etc. and whose qualities suffer little from changes in the mold processing temperature.
Other objects and effects of the present invention will become apparent from the following description.
To solve the above-mentioned problems, the present inventors have conducted extensive studies to establish a technique for improving the balance between fluidity and heat resistance. As a result, they have discovered that this object can be achieved by using a specific polymer blend composition, thus completing the present invention. That is, the above described objectives of the present invention have been achieved by providing the following composition:
(1) A polyphenylene ether resin composition which comprises:
(A) from 30 to 95% by weight of a modified polyphenylene ether resin entirely or partially modified with an unsaturated carboxylic acid or a functional derivative thereof;
(B) from 2 to 60% by weight of at least one of a polystyrene and a rubber-modified polystyrene; and
(C) from 3 to 40% by weight of a styrene/acrylonitrile copolymer having an acrylonitrile ingredient content of from not less than 7% by weight to less than 11% by weight.
(2) The composition according to the above (1), wherein said component (C) has a melt flow rate of from 5 to 100 g/10 min as determined at 220° C. with a load of 10 kg.
(3) The composition according to the above (1), further comprising (D) from 1 to 30 parts by weight of a phosphoric acid ester compound per 100 parts by weight of the total amount of said components (A), (B) and (C).
(4) The composition according to the above (3), wherein said phosphoric acid ester compound (D) is a condensed phosphoric acid ester.
(5) The composition according to the above (1), further comprising (E) from 1 to 100 parts by weight of an inorganic filler per 100 parts by weight of the total amount of said components (A), (B) and (C).
(6) The composition according to the above (1), further comprising:
(D) from 1 to 30 parts by weight of a phosphoric acid ester compound; and
(E) from 1 to 100 parts by weight of an inorganic filler, each per 100 parts by weight of the total amount of said components (A), (B) and (C).
(7) A molded article comprising a composition according
to the above (5).
(8) A molded article comprising a composition according to the above (6).
(9) A large-sized chassis comprising a composition according to the above (5).
(10) A large-sized chassis comprising a composition according to the above (6).
DETAILED DESCRIPTION OF THE INVENTION
Polyphenylene ether resin for use in the modified polyphenylene ether resin (A) according to the present invention is a homopolymer or a copolymer preferably having repeating unit(s) represented by general formula (I) and/or general formula (II).
wherein R
1
, R
2
, R
3
, R
4
, R
5
and R
6
independently represent a C
1-4
alkyl group, an aryl group, a halogen atom or a hydrogen atom, provided that R
5
and R
6
do not represent hydrogen at the same time.
Typical examples of the polyphenylene ether homopolymer resin include
poly(2,6-dimethyl-1,4-phenylene) ether,
poly(2-methyl-6-ethyl-1,4-phenylene) ether,
poly(2,6-diethyl-1,4-phenylene) ether,
poly(2-ethyl-6-n-propyl-1,4-phenylene) ether,
poly(2,6-di-n-propyl-1,4-phenylene) ether,
poly(2-methyl-6-n-butyl-1,4-phenylene) ether,
poly(2-ethyl-6-isopropyl-1,4-phenylene) ether,
poly(2-methyl-6-chloroethyl-1,4-phenylene) ether,
poly(2-methyl-6-hydroxyethyl-1,4-phenylene) ether and
poly(2-methyl-6-chloroethyl-1,4-phenylene) ether.
Among these homopolymers, poly(2,6-dimethyl-1,4-phenylene) ether is particularly preferred.
The term “polyphenylene ether copolymer” as used herein means a copolymer having a phenylene ether structure as the major monomer unit. Examples thereof include
2,6-dimethylphenol/2,3,6-trimethylphenol copolymers,
2,6-dimethylphenol/o-cresol copolymers and
2,6-dimethylphenol/2,3,6-trimethylphenol/o-cresol copolymers.
In the present invention, the polyphenylene ether resin is entirely or partially modified with an unsaturated carboxylic acid or a functional derivative thereof to be used as the modified polyphenylene ether resin (A). The modified polyphenylene ether resin can be produced by, for example, kneading a polyphenylene ether resin together with an unsaturated carboxylic acid or a functional derivative thereof in a molten state in the presence of a radical initiator such as organic peroxides, diazo compounds, etc. to react these. Examples of the unsaturated carboxylic acid and its functional derivative include maleic acid, fumaric acid, itaconic acid, halogenated maleic acid, cis-4-cyclohexne-1,2-dicarboxylic acid, endo-cis-bicyclo(2,2,1)-5-heptene-2,3-dicarboxylic acid; anhydrides, esters, amides and imides of these dicarboxylic acids; acrylic acid, methacrylic acid; and esters and amides of these monocarboxylic acids. These compounds may be used either alone or in combination of two or more thereof. Among them, unsaturated dicarboxylic acids and functional d
Ohzeki Jurou
Ueda Eiji
Yoshida Kazuo
Asahi Kasei Kabushiki Kaisha
Pennie & Edmonds LLP
Woodward Ana
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