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
2000-09-28
2003-03-18
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...
C524S538000, C525S432000
Reexamination Certificate
active
06534583
ABSTRACT:
FILED OF INVENTION
The present invention relates to inorganic reinforced polyamide resin compositions comprising crystalline polyamide resins, semi-aromatic amorphous polyamide resins, and inorganic reinforcing materials. More particularly, the present invention relates to inorganic reinforced polyamide resin compositions, which can provide shaped articles having satisfactory strength and rigidity without deteriorating their appearances (e.g., specular surface gloss, evenness of embossed surface) and further having excellent coating properties and weathering resistance, and which require a mold temperature of 100° C. or lower in the preparation of shaped articles. These inorganic reinforced polyamide resin compositions are suitable for automobile exterior parts, particularly door mirror parts.
BACKGROUND OF THE INVENTION
In general, polyamide resins have excellent mechanical characteristics, heat resistance, impact resistance, and chemical resistance; therefore they have been widely used for automobile parts, electrical appliance parts, electronic parts, domestic miscellaneous goods, and other various applications. Among these, polyamide resins reinforced with inorganic materials, typically glass fibers, have remarkably increased rigidity, strength, and heat resistance. In particular, it has been known that rigidity can be improved in proportion to the amounts of reinforcing materials added. However, if reinforcing materials such as glass fibers are added in large quantities, for example, in amounts of 50% to 70% by weight, to polyamide resins for the purpose of improving rigidity and strength, the polyamide resin compositions thus obtained provide shaped articles having extremely deteriorated appearances (e.g., specular surface gloss, evenness of embossed surface), resulting in a remarkable damage to the commercial value of these shaped articles.
Accordingly, for improving the appearances of shaped articles, there have been proposed many methods in which amorphous polyamide resins are added to crystalline polyamide resins (see, e.g., JP-A 2-140265, JP-A 3-9952, JP-A 3-269056, JP-A 4-202358).
These methods, however, cannot provide good specular surface gloss or even surface gloss of embossed surface. Further, there have been known methods for improving strength and rigidity by the addition of nylon-66, glass fibers, and mica in great amounts to semi-aromatic polyamide resins (MXD-6) (see, e.g., JP-A 1-263151). In this case, however, the temperature of a mold used in the preparation of shaped articles should be increased to high temperatures, for example, 135° C., or even if the mold temperature is increased to such high temperatures, the shaped articles thus obtained may sometimes have no good appearances.
SUMMARY OF THE INVENTION
Under these circumstances, the present inventors have extensively studied to develop a polyamide resin composition, which can provide shaped articles having satisfactory strength and rigidity without deteriorating their appearances and further having excellent coating properties and weathering resistance, and which requires a mold temperature of 100° C. or lower in the preparation of shaped articles, even if reinforcing materials such as glass fibers are added in large quantities, for example, in amounts of 50% by weight or higher, to polyamide resins for the purpose of improving strength and rigidity.
As a result, they have found that such a polyamide resin composition can be obtained by the combination of (A) a crystalline polyamide resin, (B) a semi-aromatic amorphous polyamide resin, and (C) an inorganic reinforcing material, and by the control of relative viscosity and crystallization temperature as measured with a temperature drop, of the composition after melt kneading of these ingredients, thereby completing the present invention.
Thus the present invention provides an inorganic reinforced polyamide resin composition obtainable by melt kneading of (A) a crystalline polyamide rein, (B) a semi-aromatic amorphous polyamide resin, and (C) an inorganic reinforcing material, wherein the relative viscosity of 96% sulfuric acid solution of the composition is 2.1 or lower and wherein the crystallization temperature (TC2) of the composition as measured with a temperature drop by differential scanning calorimetry (DSC) is 180° C. or lower.
REFERENCES:
Database WPI, Section Ch. Week 199236, Derwent Publications Ltd., London, GB; XP002156785 & JP 04 202358 A (Unitika Ltd.), Jul. 23, 1992.
Database WPI, Section Ch, Week 199203, Derwent Publications Ltd., London, GB; AN 1992-020295 XP002156786 & JP 03 269056 A (Mitsubishi Kasai Corp.), Nov. 29, 1991.
Database WPI, Section Ch. Week 199109, Derwent Publications Ltd., London, GB; AN 1991-061444 XP 002156787 & JP 03 009952 A (Nippon Steel Chem. Co.), Jan. 17, 1991.
Database WPI, Section Ch, Week 199027, Derwent Publications Ltd., London, GB; AN 1990-207233 XP002156788 & JP 02 140265 A (Toyoda Gosei KK), May 29, 1990.
Eguchi Hideki
Hiramatsu Toshio
Nakagawa Tomohide
Takeuchi Manabu
Tamura Tutomu
Toyo Boseki Kabushiki Kaisha
Woodward Ana
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