Flame-retarded, conductive compositions which include polyphenylene ether and polystyrene resins
AssigneeGeneral Electric Company
InventorsAnn M. Hellstern-Burnell, Kim G. Balfour
Life of this patent
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Abstract
Improved polyphenylene ether-based compositions are described, which also contain polystyrene; selected amounts of glass fibers and inorganic nonfibrous agents such as clay or mica; carbon fibers or metal-coated graphite fibers; and certain diphosphate- or polyphosphate-based flame retardant compositions. The compositions, which can be injection-molded, exhibit excellent electrical dissipation characteristics, as well as excellent flame retardancy (without cracking or "juicing"); heat distortion temperature characteristics; tensile yield; and flexural modulus. Specific methods for preparing such compositions also contribute to their enhanced performance. Furthermore, the compositions may be foamed
Claims30
An improved thermoplastic composition, comprising:
- a) polyphenylene ether resin;
- b) at least one polystyrene resin;
- c) about 3% by weight to about 30% by weight glass fibers, based on the weight of the entire composition;
- d) an effective amount of at least one inorganic, nonfibrous agent which dimensionally-stabilizes molded or extruded parts formed from the composition;
- e) about 5% by weight to about 15% by weight, based on the weight of the entire composition, of a carbon-based material selected from the group consisting of carbon fibers and metal-coated graphite fibers;
- and
- f) about 9% by weight to about 22% by weight, based on the weight of the entire composition, of a flame retardant composition which itself comprises as its major component a diphosphate or polyphosphate compound having one of the following formulae:
- ##STR4## , or mixtures thereof, wherein R.sub.1, R.sub.3 and R.sub.5 are, independently, hydrocarbon;
- R.sub.2, R.sub.5, R.sub.6 and R.sub.7 are, independently, hydrocarbon or hydrocarbonoxy;
- X.sup.1, X.sup.2 and X.sup.3 are either hydrogen, methyl, methoxy, or halogen, m and r are integers from 1 to 4;
- and n and p are integers from 1 to about 30.
A conductive thermoplastic composition exhibiting electrical dissipation characteristics;
- and comprising
- a) polyphenylene ether resin;
- b) at least one polystyrene resin;
- c) about 3% by weight to about 30% by weight glass fibers, based on the weight of the entire composition;
- d) an effective amount of at least one inorganic, nonfibrous agent which dimensionally-stabilizes molded or extruded parts formed from the composition;
- e) about 5% by weight to about 15% by weight, based on the weight of the entire composition, of a carbon-based material selected from the group consisting of carbon fibers and metal-coated graphite fibers;
- and
- f) about 9% by weight to about 22% by weight, based on the weight of the entire composition, of a flame retardant composition which itself comprises as its major component a diphosphate or polyphosphate compound having one of the following formulae:
- ##STR6## , or mixtures thereof, wherein R.sup.1, R.sup.3 and R.sup.5 are, independently, hydrocarbon;
- R.sup.2, R.sup.5, R.sup.6 and R.sup.7 are, independently, hydrocarbon or hydrocarbonoxy;
- X.sup.1, X.sup.2 and X.sup.3 are are either hydrogen, methyl, methoxy, or halogen;
- m and r are integers from 1 to 4;
- and n and p are integers from 1 to about 30;
- said composition being prepared by:
- (i) preextruding the polyphenylene ether resin;
- the polystyrene resin;
- the diphosphate compound of component (f);
- and optionally, the dimensionally-stabilizing agent of component (d), into a thermoplastic pellet characterized by a uniform dispersion of components (d) and (f) within the polyphenylene ether matrix;
- and then
- (ii) extruding the product of step (i) with the glass of component (c) and the carbon-based material of component (e);
- so as to form, upon cooling and (pelletization), thermoplastic pellets characterized by a uniform dispersion of components (c), (d), (e), and (f) within the polyphenylene ether matrix.
A thermoplastic composition, consisting essentially of
- a) polyphenylene ether resin present at a level of from 35% by weight to 55% by weight of the entire composition;
- b) at least one polystyrene resin present at a level of from 15% to 30% by weight based on the weight of the entire composition;
- c) glass fibers present at 3% by weight, 30% by weight based on the weight of the entire composition;
- d) mica present at a level of 3 to 12% by weight based on the weight of the entire composition;
- e) a carbon-based material selected from the group consisting of carbon fibers and metal-coated graphite fibers, said carbon-based material being present at a level of from 5% by weight to 15% by weight based on the weight of the entire composition;
- and
- f) tetraphenyl resorcinol diphosphate present at a level of from 9 to 22% by weight, based on the weight of the entire composition.
Dependencies are inferred from the claim text.