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
2000-02-16
2001-10-23
Mullis, Jeffrey (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...
C524S502000, C525S09200D
Reexamination Certificate
active
06306953
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to poly(arylene ether)-polystyrene compositions, and especially relates to poly(arylene ether)-polystyrene compositions having reduced volatile emissions and reduced odor.
There has long been a desire to reduce volatile emissions from thermoplastics, especially thermoplastics used in interior spaces. This desire arise from both aesthetic and toxicological concerns. Considerable effort has been invested in reducing odor and volatile emissions from poly(arylene ether) containing thermoplastics, and various solutions have been proposed.
U.S. Pat. No. 5,001,214 to White et al. describes preparation of reduced-odor poly(phenylene ether) from a purified phenolic monomer and an amine-free catalyst. U.S. Pat. No. 5,089,091 to Fox et al. describes mixing a poly(phenylene ether) resin with water to form and aqueous suspension, then distilling off the water to remove volatile impurities. Japanese patent publication number JP07-138466 describes a reduced-odor composition comprising poly(phenylene ether) resin, carbon black, and a synthetic zeolite. Japanese patent publication number JP09-279013 describes a conductive, reduced-odor composition comprising poly(phenylene ether), polystyrene, carbon black, and an aromatic carboxylic acid hydride.
There remains a need for thermoplastic compositions with reduced volatile emissions.
BRIEF SUMMARY OF THE INVENTION
Reduced emissions of styrene and butanal are exhibited by a thermoplastic composition comprising: (a) about 5 to about 95 weight percent of a poly(arylene ether); (b) about 5 to about 95 weight percent of a polystyrene; (c) optionally, about 0.1 to about 15 weight percent of a rubber material; and (d) about 0.1 to about 10 weight percent of an activated carbon derived from vegetable matter and having a surface area of about 200 to about 2,000 square meters per gram (m
2
/g); wherein all weight percents are based on the weight of the entire composition.
DETAILED DESCRIPTION OF THE INVENTION
The thermoplastic composition comprises: (a) about 5 to about 95 weight percent of a poly(arylene ether); (b) about 5 to about 95 weight percent of a polystyrene; (c) optionally, about 0.1 to about 15 weight percent of a rubber material; and (d) about 0.1 to about 10 weight percent of an activated carbon derived from vegetable matter and having a surface area of about 200 to about 2,000 m
2
/g; wherein all weight percents are based on the weight of the entire composition.
The composition comprises at least one poly(arylene ether) resin. Although all conventional poly(arylene ether)s can be employed with the present invention, polyphenylene ethers (“PPE”) are preferred. Poly(arylene ether)s per se, are known polymers comprising a plurality of structural units of the formula:
wherein for each structural unit, each Q
1
is independently halogen, primary or secondary lower alkyl (e.g., alkyl containing up to 7 carbon atoms), phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and each Q
2
is independently hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy as defined for Q
1
. Preferably, each Q
1
is alkyl or phenyl, especially C
1-4
alkyl, and each Q
2
is hydrogen.
Both homopolymer and copolymer poly(arylene ether)s are included. The preferred homopolymers are those containing 2,6-dimethylphenylene ether units. Suitable copolymers include random copolymers containing, for example, such units in combination wit 2,3,6-trimethyl1,4-phenylene ether units or copolymers derived from copolymerization of 2,6-dimethylphenol with 2,3,6-trimethylphenol. Also included are poly(arylene ether)s containing moieties prepared by grafting vinyl monomers or polymers such as polystyrenes, as well as coupled poly(arylene ether)s in which coupling agents such as low molecular weight polycarbonates, quinones, heterocycles and formals undergo reaction in known manner with the hydroxy groups of two poly(arylene ether) chains to produce a higher molecular weight polymer. Poly(arylene ether)s of the present invention further include combinations of any of the above.
The poly(arylene ether)s generally have a number average molecular weight of about 3,000 to about 40,000 and a weight average molecular weight of about 20,000 to about 80,000, as determined by gel permeation chromatography. The poly(arylene ether) generally has an intrinsic viscosity of about 0.10 to about 0.60 deciliters per gram (dL/g), preferably about 0.29 to about 0.48 dL/g, all as measured in chloroform at 25° C. It is also possible to utilize a high intrinsic viscosity poly(arylene ether) and a low intrinsic viscosity poly(arylene ether) in combination. Determining an exact ratio, when two intrinsic viscosities are used, will depend somewhat on the exact intrinsic viscosities of the poly(arylene ether) used and the ultimate physical properties that are desired.
The poly(arylene ether) is typically prepared by the oxidative coupling of at least one monohydroxyaromatic compound such as 2,6-xylenol or 2,3,6-trimethylphenol. Catalyst systems are generally employed for such coupling; they typically contain at least one heavy metal compound such as a copper, manganese or cobalt compound, usually in combination with various other materials.
Particularly useful poly(arylene ether)s for many purposes are those which comprise molecules having at least one aminoalkyl-containing end group. The aminoalkyl radical is typically located in an ortho position to the hydroxy group. Products containing such end groups may be obtained by incorporating an appropriate primary or secondary monoamine such as di-n-butylamine or dimethylamine as one of the constituents of the oxidative coupling reaction mixture. Also frequently present are 4-hydroxybiphenyl end groups, typically obtained from reaction mixtures in which a by-product diphenoquinone is present, especially in a copper-halide-secondary or tertiary amine system. A substantial proportion of the polymer molecules, typically constituting as much as about 90 weight percent of the polymer, may contain at least one of said aminoalkyl-containing and 4-hydroxybiphenyl end groups.
It will be apparent to those skilled in the art from the foregoing that the poly(arylene ether)s include all those presently known, irrespective of variations in structural units or ancillary chemical features.
A suitable amount of poly(arylene ether) in the composition is about 5 to about 95 weight percent, with a preferred amount being about 20 to about 80 weight percent. An amount of about 25 to about 75 weight percent is more preferred.
The composition further comprises at least one polystyrene. The term “polystyrene” as used herein includes polymers prepared by methods known in the art including bulk, suspension and emulsion polymerization, which contain at least 25 weight percent of structural units derived from a monomer of the formula:
wherein R
1
is hydrogen, lower alkyl having from 1 to about 7 carbon atoms, or halogen; Z
1
is vinyl, halogen or lower alkyl having from 1 to about 7 carbon atoms; and p is from 0 to 5. These resins include homopolymers of styrene, chlorostyrene and vinyltoluene; random copolymers of styrene with one or more monomers illustrated by acrylonitrile, butadiene, alpha-methylstyrene, ethylvinylbenzene, divinylbenzene and maleic anhydride; and rubber-modified polystyrenes comprising blends and grafts, wherein the rubber is a polybutadiene or a rubbery copolymer of about 70 to about 98 weight percent styrene and about 2 to about 30 weight percent diene monomer; and the like and combinations and reaction products comprising at least one of the foregoing. Polystyrenes are known to be miscible with poly(arylene ether)s in all proportions, and the composition may contain polystyrene in an amount of about 5 to about 95 weight percent, preferably about 25 to about 75 weight percent, more preferably about 40 to about 60 weight percent, based on the weight of the entire compos
Fortuyn Johannes E.
Liska Juraji
General Electric Co.
Mullis Jeffrey
LandOfFree
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