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
2000-11-09
2002-12-31
Cain, Edward J. (Department: 1714)
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...
C524S320000, C524S321000, C524S495000
Reexamination Certificate
active
06500895
ABSTRACT:
FEDERALLY SPONSORED RESEARCH
Not Applicable
BACKGROUND OF THE INVENTION
The present invention relates to a thermoplastic blend. In particular, the invention relates to an improved thermoplastic blend comprising a poly(arylene ether) and a polyamide and having an enhanced retention of physical properties.
Thermoplastic blends comprising poly(arylene ether)s and polyamides are commercially available materials that combine the heat resistance, stiffness and impact strength of the amorphous poly(arylene ether) phase with the chemical resistance and processability of the crystalline polyamide phase. Their exceptional balance of thermal and mechanical properties has led to adoption of these blends by the automotive industry for use in painted body panels. Body panels are large parts and are often commercially formed using injection molding techniques. These injection molding techniques often subject the thermoplastic blends to elevated temperatures for long periods of time and often result in diminished morphological stability and reduced physical properties.
There therefore remains a need for poly(arylene ether)/polyamide blends with retention of physical properties and having reduced water retention and improved paint adhesion.
BRIEF SUMMARY OF THE INVENTION
A poly(arylene ether)/polyamide blend having reduced water absorption comprises:
about 5 to about 95 weight percent of a poly(arylene ether);
about 5 to about 95 weight percent of a polyamide;
about 0.01 to about 10 weight percent of a compatibilizing agent;
about 0.1 to about 20 weight percent of a polyester ionomer which is the polycondensation product of (1) an aromatic dicarboxylic acid or its ester-forming derivative; (2) a diol compound or its ester-forming derivative; and (3) an ester-forming compound containing an ionic sulfonate group; and
an amount of a stabilizer package effective to enhance the morphological stability of the poly(arylene ether)/polyamide blend wherein the stabilizer package comprises at least one phenolic species in combination with at one thioester species, at least one one organo-phosphite species, or at least one thioester species in combination with at least one organo-phosphite species,
wherein weight percentages are based on the total weight of the composition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Thermoplastic blends exhibiting reduced water absorption, improved paint adhesion, and improved conductivity comprise:
about 5 to about 95 weight percent of a poly(arylene ether);
about 5 to about 95 weight percent of a polyamide;
about 0.01 to about 10 weight percent of a compatibilizing agent;
about 0.1 to about 20 weight percent of a polyester ionomer which is the polycondensation product of (1) an aromatic dicarboxylic acid or its ester-forming derivative; (2) a diol compound or its ester-forming derivative; and (3) an ester-forming compound containing an ionic sulfonate group; and
an amount of a stabilizer package effective to enhance the morphological stability of the thermoplastic blends wherein the stabilizer package comprises at least one phenol species in combination with at one thioester species, at least one one organo-phosphite species, or at least one thioester material in combination with at least one organo-phosphite species,
wherein weight percentages are based on the total weight of the composition.
The composition may comprise any conventional poly(arylene ether). The term poly(arylene ether) includes polyphenylene ether (PPE) and poly(arylene ether) copolymers; graft copolymers; poly(arylene ether) ether ionomers; and block copolymers of alkenyl aromatic compounds, vinyl aromatic compounds, and poly(arylene ether), and the like; and combinations comprising at least one of the foregoing; and the like. 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 having 1 to about 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
14
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 with 2,3,6-trimethyl-1,4-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) 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) generally has a number average molecular weight within the range of about 3,000 to about 40,000 and a weight average molecular weight within the range 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 in the range of 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 desired.
The poly(arylene ether)s are 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 that 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% by weight 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 suitable poly(arylene ether)s include all those presently known, irrespective of variations in structural units or ancillary chemical features.
The composition may comprise poly(arylene ether) in an amount of about 5 to about 95 weight percent, based on the total weight of the composition. It is preferred to use the poly(arylene ether) in an amount of about 20 to about 60 weight percent, more preferably about 30 to about 45 weight percent.
Suitable polyamide resins are a generic family of resins known as nylons, characterized by the presence of an amide group (—C(O)NH—). Nylon-6 and nylon-6,6 are the generally preferred polyamides and are available fr
Bastiaens Jozef H. P.
Carminati Alessio
Cain Edward J.
General Electric Company
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