Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-12-20
2003-08-12
Seidleck, James J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S158000, C524S161000, C524S121000, C524S127000
Reexamination Certificate
active
06605659
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to flame retardant polycarbonate resin/ABS graft copolymer blends that exhibit improved performance.
BRIEF DESCRIPTION OF THE RELATED ART
Flame retardant thermoplastic compositions that contain an aromatic polycarbonate resin and a benzenesulfonic acid salt have been found to exhibit good flame retardancy, see for example U.S. Pat. No. 4,220,583.
Flame retardant thermoplastic resin compositions that contain an aromatic polycarbonate resin, an ABS graft copolymer, a fluoropolymer and an organophosphate flame retardant are known and have been found to exhibit good flame retardency and good heat resistance, see, for example, coassigned U.S. Pat. No. 5,204,394.
Flame retardant resin compositions that exhibit low melt viscosity and impart improved aesthetic appearance, particularly, improved resistance to streaking, and improved physical properties, particularly, improved resistance to edge cracking, to articles molded therefrom are desired.
SUMMARY OF THE INVENTION
In one embodiment the thermoplastic resin composition of the present invention comprises:
(a) an aromatic polycarbonate resin,
(b) a rubber modified graft copolymer comprising a discontinuous rubber phase dispersed in a continuous rigid thermoplastic phase, wherein at least a portion of the rigid thermoplastic phase is chemically grafted to the rubber phase
(c) a flame retarding amount of an alkali metal or alkaline earth metal salt of an sulfonic acid flame retardant compound selected from the group consisting of:
where R is independently for each substitution a one to forty carbon atom alkyl, aralkyl or aromatic group, M is a metal selected from the group of alkali metals and alkaline earth metals with x the oxidation state of the metal, M, where i, j, k and m are each integers ranging from 0 to 5 subject to the limitation that i+k is at least 1 and subject to the further limitation that i+j is less than or equal to 5 and k+m is less than or equal to 5.
DETAILED DESCRIPTION OF THE INVENTION
In a preferred embodiment, the thermoplastic resin composition of the present invention comprises, based on 100 parts by weight (“pbw”) of thermoplastic resin composition, from 55 to 80 pbw, more preferably from 50 to 90 pbw, even more preferably from 40 to 96 pbw, of the aromatic polycarbonate resin, from 14 to 39 pbw, more preferably from 8 to 48 pbw, even more preferably from 4 to 59 pbw, of the rubber modified graft copolymer and from 0 to 20 pbw, more preferably from 2 to 15 pbw, even more preferably from 6 to 12 pbw, of the organophosphate flame retardant.
Aromatic polycarbonate resins suitable for use as the polycarbonate resin component of the thermoplastic resin composition of the present invention are known compounds whose preparation and properties have been described, see, generally, U.S. Pat. Nos. 3,169,121, 4,487,896 and 5,411,999, the respective disclosures of which are each incorporated herein by reference.
In a preferred embodiment, the aromatic polycarbonate resin component of the present invention is the reaction product of a dihydric phenol according to the structural formula (I):
HO—A—OH (I)
wherein A is a divalent aromatic radical,
with a carbonate precursor and contains structural units according to the formula (II):
wherein A is defined as above.
As used herein, the term “divalent aromatic radical” includes those divalent radicals containing a single aromatic ring such as phenylene, those divalent radicals containing a condensed aromatic ring system such as, for example, naphthlene, those divalent radicals containing two or more aromatic rings joined by a non-aromatic linkage, such as for example, an alkylene, alkylidene or sulfonyl group, any of which may be substituted at one or more sites on the aromatic ring with, for example, a halo group or (C
1
-C
6
)alkyl group.
In a preferred embodiment, A is a divalent aromatic radical according to the formula (III):
Suitable dihydric phenols include, for example, one or more of 2, 2-bis-(4-hydroxyphenyl) propane (“bisphenol A”), 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl) methane, 4,4-bis(4-hydroxyphenyl)heptane, 3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane, 2,6-dihydroxy naphthalene, hydroquinone, 2,4′-dihydroxyphenyl sulfone. In a highly preferred embodiment, the dihydric phenol is bisphenol A.
The carbonate precursor is one or more of a carbonyl halide, a carbonate ester or a haloformate. Suitable carbonyl halides include, for example, carbonyl bromide and carbonyl chloride. Suitable carbonate esters include, such as for example, diphenyl carbonate, dichlorophenyl carbonate, dinaphthyl carbonate, phenyl tolyl carbonate and ditolyl carbonate. Suitable haloformates include, for example, bishaloformates of dihydric phenols, such as, for example, hydroquinone, or glycols, such as, for example, ethylene glycol, neopentyl glycol. In a highly preferred embodiment, the carbonate precursor is carbonyl chloride.
Suitable aromatic polycarbonate resins include linear aromatic polycarbonate resins, branched aromatic polycarbonate resins. Suitable linear aromatic polycarbonates resins include, e.g., bisphenol A polycarbonate resin.
Suitable branched polycarbonates are known and are made by reacting a polyfunctional aromatic compound with a dihydric phenol and a carbonate precursor to form a branched polymer, see generally, U.S. Pat. Nos. 3,544,514, 3,635,895 and 4,001,184, the respective disclosures of which are incorporated herein by reference. The polyfunctional compounds are generally aromatic and contain at least three functional groups which are carboxyl, carboxylic anhydrides, phenols, haloformates or mixtures thereof, such as, for example, 1,1,1-tri(4-hydroxyphenyl)ethane, 1,3,5,-trihydroxybenzene, trimellitic anhydride, trimellitic acid, trimellityl trichloride, 4-chloroformyl phthalic anhydride, pyromellitic acid, pyromellitic dianhydride, mellitic acid, mellitic anhydride, trimesic acid, benzophenonetetracarboxylic acid, benzophenone-tetracarboxylic dianhydride. The preferred polyfunctional aromatic compounds are 1,1,1-tri(4-hydroxyphenyl)ethane, trimellitic anhydride or trimellitic acid or their haloformate derivatives.
In a preferred embodiment, the polycarbonate resin component of the present invention is a linear polycarbonate resin derived from bisphenol A and phosgene.
In a preferred embodiment, the weight average molecular weight of the polycarbonate resin is from about 10,000 to about 200,000 grams per mole (“g/mol”), as determined by gel permeation chromatography relative to polystyrene. Such resins typically exhibit an intrinsic viscosity of about 0.3 to about 1.5 deciliters per gram in methylene chloride at 25° C.
Polycarbonate resins are made by known methods, such as, for example, interfacial polymerization, transesterification, solution polymerization or melt polymerization.
Copolyester-carbonate resins are also suitable for use as the aromatic polycarbonate resin component of the present invention. Copolyester-carbonate resins suitable for use as the aromatic polycarbonate resin component of the thermoplastic resin composition of the present invention are known compounds whose preparation and properties have been described, see, generally, U.S. Pat. Nos. 3,169,121, 4,430,484 and 4,487,896, the respective disclosures of which are each incorporated herein by reference.
Copolyester-carbonate resins comprise linear or randomly branched polymers that contain recurring carbonate groups, carboxylate groups and aromatic carbocyclic groups in the polymer chain, in which at least some of the carbonate groups are bonded directly to the ring carbon atoms of the aromatic carbocyclic groups.
In a preferred embodiment, the copolyester-carbonate resin component of the present invention is derived from a carbonate precursor, at least one dihydric phenol and at least one dicarboxylic acid or dicarboxylic acid equivalent. In a preferred embodiment, the dicarboxylic acid is one according to the formula (IV):
wherein A′ is alkylene, alky
Blackburn Kirk J.
Gallucci Robert R.
Georgiev Emil M.
Rajguru U. K
Seidleck James J.
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