Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-11-12
2003-09-02
Buttner, David J. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S130000, C524S133000, C524S137000, C524S139000, C524S140000, C524S141000, C524S143000, C524S154000, C524S165000, C524S166000
Reexamination Certificate
active
06613824
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is related to flame retardant resinous compositions comprising (i) at least one aromatic polycarbonate; (ii) at least one of a second polymer having structural units derived from one or more monomers selected from the group consisting of vinyl aromatic monomers, monoethylenically unsaturated nitrile monomers, and C
1
-C
12
alkyl (meth)acrylate monomers; and (iii) at least one rubber modified graft copolymer. In the literature different methods for improving the flame resistance of compositions comprising aromatic polycarbonate resins are described. Typically the methods use either halogenated flame retardants which are said to create potential environmental hazards or phosphate flame retardants which negatively affect the physical properties of the blends, for example by lowering the heat resistance properties. A method is needed for eliminating or reducing the amount of halogenated or phosphate flame retardants in aromatic polycarbonate-comprising compositions which results in good flame resistance without deterioration in other desirable properties.
Flame retardant polycarbonate compositions which contain certain sulfonate salts in combination with phosphates have been reported in commonly owned U.S. Pat. No. 5,204,394. However, such compositions often show poor flame resistance performance after conditioning in a humid atmosphere, which conditions may be similar to those experienced by commercial articles made from such compositions. Accordingly, there remains a need for developing flame retardant systems applicable to compositions comprising a polycarbonate.
SUMMARY OF THE INVENTION
The present inventors have discovered flame retardant resinous compositions which provide, among other beneficial properties, improved flame resistance after conditioning in a humid atmosphere. These flame retardant resinous compositions comprise:
(i) at least one aromatic polycarbonate;
(ii) at least one of a second polymer having structural units derived from one or more monomers selected from the group consisting of vinyl aromatic monomers, monoethylenically unsaturated nitrile monomers, and C
1
-C
12
alkyl (meth)acrylate monomers;
(iii) at least one rubber modified graft copolymer;
(iv) at least one polymeric or non-polymeric organic phosphorus species;
(v) at least one antidrip agent; and
(vi) at least one perfluoroalkanesulfonate salt present in an amount in a range between about 0.01 wt % and about 0.25 wt %, based on the weight of the entire composition.
Various other features, aspects, and advantages of the present invention will become more apparent with reference to the following description and appended claims.
DETAILED DESCRIPTION
The flame retardant resinous compositions of the present invention comprise at least one aromatic polycarbonate resin. Aromatic polycarbonate resins suitable for use in the present invention comprise structural units derived from at least one dihydric phenol and a carbonate precursor. Suitable dihydric phenols include those represented by the formula (I):
HO—D—OH (I)
wherein D comprises a divalent aromatic radical. In various embodiments D has the structure of formula (II);
wherein A
1
represents an aromatic group such as phenylene, biphenylene, naphthylene, etc. In some embodiments E may be an alkylene or alkylidene group including, but not limited to, methylene, ethylene, ethylidene, propylene, propylidene, isopropylidene, butylene, butylidene, isobutylidene, amylene, amylidene, isoamylidene. When E is an alkylene or alkylidene group, it may also consist of two or more alkylene or alkylidene groups connected by a moiety different from alkylene or alkylidene, such as an aromatic linkage; a tertiary amino linkage; an ether linkage; a carbonyl linkage; a silicon-containing linkage; or a sulfur-containing linkage including, but not limited to, sulfide, sulfoxide, sulfone; or a phosphorus-containing linkage including, but not limited to, phosphinyl, phosphonyl. In other embodiments E may be a cycloaliphatic group including, but not limited to, cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, methylcyclohexylidene, 2-[2.2.1]-bicycloheptylidene, neopentylidene, cyclopentadecylidene, cyclododecylidene, adamantylidene; a sulfur-containing linkage, such as sulfide, sulfoxide or sulfone; a phosphorus-containing linkage, such as phosphinyl or phosphonyl; an ether linkage; a carbonyl group; a tertiary nitrogen group; or a silicon-containing linkage such as silane or siloxy. R
1
represents hydrogen or a monovalent hydrocarbon group such as alkyl, aryl, aralkyl, alkaryl, or cycloalkyl. In various embodiments a monovalent hydrocarbon group of R
1
may be halogen-substituted, particularly fluoro- or chloro-substituted, for example as in dichloroalkylidene. Y
1
may be an inorganic atom including, but not limited to, halogen (fluorine, bromine, chlorine, iodine); an inorganic group including, but not limited to, nitro; an organic group including, but not limited to, a monovalent hydrocarbon group such as alkyl, aryl, aralkyl, alkaryl, or cycloalkyl, or an oxy group such as OR
2
, wherein R
2
is a monovalent hydrocarbon group such as alkyl, aryl, aralkyl, alkaryl, or cycloalkyl; it being only necessary that Y
1
be inert to and unaffected by the reactants and reaction conditions used to prepare a polycarbonate. In some particular embodiments Y
1
comprises a halo group or C
1
-C
6
alkyl group. The letter “m” represents any integer from and including zero through the number of positions on A
1
available for substitution; “p” represents an integer from and including zero through the number of positions on E available for substitution; “t” represents an integer equal to at least one; “s” is either zero or one; and “u” represents any integer including zero.
When more than one Y
1
substituent is present as represented by formula (II) above, they may be the same or different. When more than one R
1
substituent is present, they may be the same or different. Where “s” is zero in formula (II) and “u” is not zero, the aromatic rings are directly joined with no intervening alkylidene or other bridge. The positions of the hydroxyl groups and Y
1
on the aromatic residues A
1
can be varied in the ortho, meta, or para positions and the groupings can be in vicinal, asymmetrical or symmetrical relationship, where two or more ring carbon atoms of the aromatic residue are substituted with Y
1
and hydroxyl groups.
Some illustrative, non-limiting examples of dihydric phenols of formula (I) include the dihydroxy-substituted aromatic hydrocarbons disclosed by name or formula (generic or specific) in U.S. Pat. No. 4,217,438. In some embodiments of the invention dihydric phenols include 6-hydroxy-1-(4′-hydroxyphenyl)-1,3,3-trimethylindane, 4,4′-(3,3,5-trimethylcyclohexylidene)diphenol; 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane; 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol-A); 4,4-bis(4-hydroxyphenyl)heptane; 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane; 2,2-bis(4-hydroxy-3-methylphenyl)propane; 2,2-bis(4-hydroxy-3-ethylphenyl)propane; 2,2-bis(4-hydroxy-3-isopropylphenyl)propane; 2,4′-dihydroxydiphenylmethane; bis(2-hydroxyphenyl)methane; bis(4-hydroxy-phenyl)methane; bis(4-hydroxy-5-nitrophenyl)methane; bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane; 1,1-bis(4-hydroxyphenyl)ethane; 1,1-bis(4-hydroxy-2-chlorophenyl)ethane; 2,2-bis(3-phenyl-4-hydroxyphenyl)-propane; bis(4-hydroxyphenyl)cyclohexylmethane; 2,2-bis(4-hydroxyphenyl)-1-phenylpropane; 3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane; 2,4′-dihydroxyphenyl sulfone; 2,6-dihydroxy naphthalene; 6,6′-dihydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane (sometimes know as “SBI”); hydroquinone, resorcinol; C
1-3
alkyl-substituted resorcinols. In a particular embodiment the dihydric phenol comprises bisphenol A.
Suitable dihydric phenols also include those containing indane structural units such as represented by the formula (III), which compound is 3-(4-hy
Campbell John Robert
Ebeling Thomas Arnold
Marugan Monica
Miebach Thomas
Buttner David J.
Cabou Christian G.
General Electric Company
Johnson Noreen C.
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