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
2001-05-11
2003-04-01
Woodward, Ana (Department: 1711)
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...
C525S432000
Reexamination Certificate
active
06541559
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to polyamide resin compositions having excellent mechanical properties and moldability and showing excellent weld strength. The resin compositions are used as materials for automobiles or electrical or electronic parts.
BACKGROUND OF THE INVENTION
Crystalline polyamide resins have widely been used as industrial materials owing to their high strength and rigidity. However, reinforced polyamides using only crystalline polyamides as polyamide show insufficient weld strength due to their crystallinity when subjected to welding which has become often used in recent years in production of resinous parts. Thus, they can not be used for parts requiring a high weld strength. In cases when polyamides composed of non-crystalline polyamides alone are used, there can be obtained enough vibration weld strength, but moldability, in particular flowability, is so poor that injection weld strength is low, which has limited the use of them.
With the recent increase in number of parts formed by using welding technique, various investigations have been made as to techniques for improving weld strength of crystalline polyamides. JP-A-9-176484 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”) and JP-A-10-219106 propose a technique of using copper iodide and potassium iodide to improve welding properties of nylon. However, this technique involves the problem that, since the amounts of actually used potassium iodide and copper iodide are so large, there result decreased mechanical strength and generation of a decomposition gas upon molding. JP-A-8-337718 proposes a technique of using a crystalline copolymer nylon. In cases of using the copolymer nylon, welding properties are markedly improved, but there result decreased mechanical strength and decreased rigidity and decreased durability including heat resistance, which limits the use of the copolymer nylon.
Compositions analogous to the composition of the present invention have long been known, and are disclosed in JP-A-58-53949 and JP-A-58-53950. These inventions, however, are techniques for improving metal halide resistance, hot water resistance or warping resistance of aliphatic nylons, and hence a larger amount of non-crystalline nylon is required to be added in comparison with the present invention. It has not been known at all to obtain the effect of improving welding properties within the composition range of the present invention.
SUMMARY OF THE INVENTION
The present invention provides a polyamide resin composition which shows excellent flowability upon molding, high cycling properties, and high weld strength when subjected to various welding methods, thus solving the above-described problems.
As a result of intensive investigations to solve the problems, the inventors of the present invention have found that the problems can be solved by adding a non-crystalline, partially aromatic copolymerized polyamide resin containing at least two aromatic monomer components in an extremely small amount to a crystalline polyamide resin, thus having completed the present invention based on the finding.
That is, the present invention relates to a polyamide resin molding composition, which shows excellent weld strength and which comprises:
(A) 96 to 99.9% by weight of a crystalline polyamide resin and;
(B) 0.1 to 4% by weight of a non-crystalline, partially aromatic, copolymerized polyamide resin containing at least two aromatic monomer components, with the total content of the crystalline polyamide and the non-crystalline, partially aromatic, copolymerized polyamide resin being 100% by weight.
Further, the present invention relates to a polyamide resin molding composition, which further comprises (C) 5 to 200 parts by weight of an inorganic filler per 100 parts by weight of the above-described polyamide resin molding composition.
REFERENCES:
patent: 4404317 (1983-09-01), Epstein et al.
patent: 0 400 428 (1990-12-01), None
patent: 0 934 979 (1999-08-01), None
patent: 1 018 534 (2000-07-01), None
patent: 58-53949 (1983-03-01), None
patent: 58-53950 (1983-03-01), None
patent: 06263895 (1994-09-01), None
patent: 0 728 812 (1996-08-01), None
patent: 8-337718 (1996-12-01), None
patent: 9-176484 (1997-07-01), None
patent: 09 241505 (1997-09-01), None
patent: 10-219106 (1998-08-01), None
patent: WO 95/26868 (1995-10-01), None
Miyamoto Akio
Nakamura Ken
Akin Gump Strauss Hauer & Feld L.L.P.
UBE Industries Ltd.
Woodward Ana
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