Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-09-24
2002-03-19
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S141000, C524S145000, C524S127000, C524S449000
Reexamination Certificate
active
06359043
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
FEDERALLY SPONSORED RESEARCH
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to glass fiber reinforced poly(phenylene ether) resin compositions, and more particularly relates to flame resistant, glass fiber reinforced poly(phenylene ether) resin compositions.
2. Brief Description of the Related Art
Poly(phenylene ether) resins (referred to hereafter as “PPE”) are commercially attractive materials because of their unique combination of physical, chemical, and electrical properties. Commercially, most PPE are sold as blends with predominantly high impact polystyrene resins. PPE are miscible with polystyrene resins in all proportions and because of the very high glass transition temperatures of PPE, the blends of PPE with polystyrene resins possess higher heat resistance than that of the polystyrene resins alone. Moreover, the combination of PPE and high impact polystyrene resins with glass fiber reinforcement results in additional overall properties such as increased stiffness. Examples of such blends can be found in U.S. Pat. Nos. 3,383,435; 4,097,550; 4,113,800; 4,101,503, 4,101,504; 4,101,505; 4,128,602; 4,139,574; and 4,154,712 among others.
The properties of these blends can be further enhanced by the addition of various additives such as flame retardants, light stabilizers, processing stabilizers, heat stabilizers, antioxidants, and other fillers. Many applications such as internal frames and parts for computer printers and facsimile machines require a combination of high stiffness, outstanding dimensional stability over a wide temperature range, and a flame resistance rating of V-0 under the Underwriter's Laboratory UL94 protocol at the wall thickness corresponding to the approximate wall thickness of the application article. As the internal frames and parts have increased in functionality and decreased in wall thickness, achieving a V-0 rating has become increasingly difficult. Presently, resin materials need to be rated V-0 under the UL94 protocol when measured at a 1.6 mm wall thickness.
It is therefore apparent that there continues to be a need for improved compositions as well as processes to manufacture compositions containing polyphenylene ether resins that are rated V-0 under the UL94 protocol when measured at a 1.6 mm wall thickness.
SUMMARY OF THE INVENTION
The present invention involves thermoplastic compositions comprising (a) a polyphenylene ether resin; (b) at least one polystyrene resin; (c) about 5% by weight to about 20% by weight of an organophosphate compound; (d) about 5% by weight to about 40% by weight of glass fibers; and (e) an amount of mica effective to render the composition V-0 when measured at a thickness of 1.6 mm; wherein all weights are based on the weight of the entire composition.
DESCRIPTION OF THE DRAWINGS
Not applicable
DETAILED DESCRIPTION OF THE INVENTION
As previously discussed, the compositions of the present invention comprise polyphenylene ether resin, polystyrene resin, glass fibers, an organophosphate compound and an amount of mica effective to render the composition V-0 when measured at a thickness of 1.6 mm.
PPE, 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 PPE are included. The preferred homopolymers are those containing 2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers include random copolymers containing, for example, such units in combination with 2,3,6-trimethyl-1,4-phenylene ether units. Also included are PPE containing moieties prepared by grafting vinyl monomers or polymers such as polystyrenes, as well as coupled PPE 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 PPE chains to produce a higher molecular weight polymer.
It will be apparent to those skilled in the art from the foregoing that the PPE contemplated for use in the present invention include all those presently known, irrespective of variations in structural units or ancillary chemical features.
The PPE generally have an intrinsic viscosity often between about 0.10-0.60 dl./g., preferably in the range of about 0.30-048 dl./g., all as measured in chloroform at 25° C. It is also possible to utilize a higher intrinsic viscosity PPE and a lower intrinsic viscosity PPE in combination. Determining an exact ratio, when two intrinsic viscosities are used, will depend somewhat on the exact intrinsic viscosities of the PPE used and the ultimate physical properties that are desired.
The PPE compositions of the present invention preferably contain at least one nonelastomeric polymer of an alkenylaromatic compound. Suitable polymers of this type may be prepared by methods known in the art including bulk, suspension and emulsion polymerization. They generally contain at least about 25% by weight of structural units derived from an alkenylaromatic monomer of the formula:
wherein G is hydrogen, lower alkyl or halogen; Z is vinyl, halogen or lower alkyl; 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, &agr;-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 98-68% styrene and about 2-32% diene monomer. These rubber modified polystyrenes include high impact polystyrene (commonly referred to as HIPS). Non-elastomeric block copolymer compositions of styrene and butadiene can also be used that have linear block, radial block or tapered block copolymer architectures. They are commercially available from such companies as Fina Oil as under the trademark FINACLEAR and Phillips under the trademark K-RESINS.
The amount of the polymer of a nonelastomeric alkenylaromatic compound, i.e. polystyrene resin, is an amount effective to improve the flow and processability of the composition. Improved flow can be indicated by reduced viscosity or reduced injection pressures needed to fill a part during an injection molding process. Generally, the nonelastomeric alkenylaromatic compound is utilized in the range of about 2% to about 40% by weight based on the total weight of the composition. The preferred range is about 4% to about 30% by weight; based on the total weight of the composition.
The compositions of the present invention also comprise at least one flame retardant, generally an organic phosphate. The organic phosphate is preferably an aromatic phosphate compound of the formula:
where R is the same or different and is alkyl, cycloalkyl, aryl, alkyl substituted aryl, halogen substituted aryl, aryl substituted alkyl, halogen, or a combination of any of the foregoing, provided at least one R is aryl.
Examples include phenyl bisdodecyl phosphate, phenylbisneopentyl phosphate, phenyl-bis (3,5,5′-tri-methyl-hexyl phosphate), ethyldiphenyl phosphate, 2-ethyl-hexyldi(p-tolyl) phosphate, bis-(2-ethylhexyl) p-tolylphosphate, tritolyl phosphate, bis-(2-ethylhexyl) phenyl phosphate, tri-(nonylphenyl) phosphate, di (dodecyl) p-tolyl phosphate, tricresyl phosphate, triphenyl phosphate, dibutylphenyl phosphate, 2-chloroethyldiphenyl phosphate, p-tolyl bis(2,5,5′-trimethylhexyl) phosphate, 2-ethylhexyldiphenyl phosphate, and the like. The preferred phos
Asinovsky Olga
Cantor & Colburn LLP
Seidleck James J.
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