Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1980-04-01
1982-07-20
Lieberman, Paul
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525397, 525423, 525425, 525432, 525436, 525537, 525905, 525906, 525930, 525928, C08L 8104, C08L 7908
Patent
active
043406971
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a heat resistant molding resin composition which is excellent in heat resistant properties. In more detail, the present invention relates to a polyamideimide resin composition which is excellent in balancing of melt viscosity characteristics and mechanical characteristics.
DISCUSSION OF THE PRIOR ART
Polyimide resins, represented by the trademarks "VESPEL SP" of DuPont in the United States and "POLYIMIDE 2080" of Upjohn in the United States, are very excellent in heat resistance, mechanical strength, chemical resistance and electrical characteristics, but they lack melt processability and cannot be melt molded. In order to improve this defect, it has been proposed that better melt moldability may be imparted to a polyimide, for example, "POLYIMIDE 2080" mentioned above, by blending it with 30 to 50% by weight of polyphenylene sulfide (U.S. Pat. No. 4,017,555). However, as the polyimide resin itself is deficient in melt processability, a relatively large amount of the polyphenylene sulfide resin is necessary in the blend for imparting an acceptable melt processability to the polyimide. Therefore, the thus obtained melt moldable composition exhibits poor mechanical properties in comparison with the inherent properties of the polyimide itself.
The aromatic polyamideimide resin represented by the trademark "TORLON" of Amoco in the United States, has both a polyimide linkage and a polyamide linkage in the high polymer main chain. Therefore, it can be tentatively melt molded, and at the same time it has excellent heat resistance, mechanical strength, chemical resistance and electrical characteristics, similar to those of a polyimide resin. Therefore, the polyamideimide resins can supply high-performance industrial material parts via high productivity molding methods, and have been attracting attention in various fields.
However, aromatic polyamideimide resins have a considerably high melt viscosity in comparison with conventionally utilized thermoplastic molding materials, and they are melt blended and melt molded only with considerable difficulty. When one attempts to obtain a shaped article therefrom by use of injection molding machines, the process must be practiced under strict conditions, such as a mold temperature of at least 200.degree. C., an injection pressure of 1,000-2,000 kg/cm.sup.2, as well as other strictly controlled conditions held within a very narrow range (for example, residence time of the resin, resin temperature, screw shape and mold structure). Thus, the melt characteristics and other properties of polyamideimide still remain unsatisfactory for obtaining a sufficient molding productivity. Furthermore, when fillers are blended with an aromatic polyamideimide resin, the melt viscosity further rises in proportion to the increase of their blending amounts, and at blending amounts higher than a certain value, it becomes difficult to or impossible to melt blend and melt mold the composition.
Therefore, we, the present inventors, have conducted strenuous studies aimed at improving the melt viscosity and uniform melt blendability of aromatic polyamideimide resin or its composite, including fillers. We have found that by blending a certain kind of thermoplastic resin in a specific amount range, a composition having well balanced and excellent melt viscosity characteristics, melt moldability, and mechanical properties, can be obtained and realized by the present invention.
SUMMARY OF THE INVENTION
The present invention comprises a heat resistant molding resin having 60 to 99.9% by weight of:
(a) an aromatic polyamideimide resin having, as a main structural unit, a repeating unit represented by the general formula: ##STR1## (wherein Ar represents a trivalent aromatic group containing at least one aromatic ring, R represents a divalent aromatic and/or aliphatic residue and R' represents hydrogen, a methyl group or a phenyl group), and 40 to 0.1% by weight of:
(b) at least one thermoplastic resin selected from the group consisting of a polyphenylene sulfide resin
REFERENCES:
patent: 4017555 (1977-04-01), Alvarez
patent: 4132823 (1979-01-01), Blackwell
patent: 4292416 (1981-09-01), Shue
Journal of Polymer Science, vol. 12, 589-601, (1974).
Aya Toshihiko
Kubo Yasushi
Lieberman Paul
Miller Austin R.
Toray Industries Inc.
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