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
2001-08-21
2002-09-03
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...
C524S413000, C524S424000, C524S428000, C524S430000, C524S431000, C524S433000, C524S434000, C524S435000, C524S436000, C524S437000, C524S443000, C524S451000, C524S538000, C525S432000
Reexamination Certificate
active
06444739
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polyamide resin molding composition, specifically, to a polyamide resin composition having a good molding cycle because of its shortened crystallization time. More specifically, the present invention relates to a polyamide resin composition which provides, owing to its shortened crystallization time, a shaped article being excellent in the retention of rigidity at 100° C. or higher, the durability under a high temperature condition, and the retention of mechanical properties after water-absorption, thereby being capable of serving as a metal replacement.
2. Description of the Prior Art
Shaped articles of polyamide resins, typically, such as nylon 6 and nylon 66, have been extensively used as metal replacements in various applications such as automobile parts, mechanical parts and electric or electronic parts because of their excellent toughness, chemical resistance and electric characteristics. In some applications of the metal replacement, the polyamide shaped articles are further required to have a good retention of mechanical properties after water-absorption, and a good durability under a high temperature condition in addition to good mechanical properties such as strength and elastic modulus.
Conventional polyamide resins produced by polycondensing
-1,4
-bis(aminomethyl)cyclohexane with adipic acid (hereinafter occasionally referred to merely as “polyamide BAC6”) are disclosed, for example, in Japanese Patent Publication Nos. 38-648 and 4-022781. These prior arts are however merely related to the process for the production of the polyamide BAC6 and its use as a packaging container.
Thus, hitherto, there are neither known nor industrially utilized any polyamide BAC6 resin composition having a good molding cycle which can produce shaped articles having an excellent retention of rigidity, a high durability under a high temperature condition and an excellent retention of mechanical properties after water-absorption.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a polyamide resin composition having a good molding cycle which can produce shaped articles excellent in the retention of rigidity at 100° C. or higher, the durability under a high temperature condition and the retention of mechanical properties even after water-absorption.
As a result of extensive study in view of the above object, the inventors have found that a resin composition prepared by blending a nucleating agent for crystallization with a specific polyamide resin has a good molding cycle and shaped articles thereof have the above-described excellent properties. The present invention has been accomplished on the basis of this finding.
Thus, the present invention provides a polyamide resin composition comprising:
100 parts by mass of a copolyamide resin (A) which is produced by polycondensing a diamine component (a) comprising 70 to 100 mol % of a diamine component (I) and 30 to 0 mol % of a diamine component (II) with a dicarboxylic acid component (b), the diamine component (I) comprising 30 to 70 mol % of trans-1,4-bis(aminomethyl)cyclohexane and 70 to 30 mol % of cis-1,4-bis(aminomethyl)cyclohexane with the combined molar percentages of the cis-trans isomers being 100 mol %, the diamine component (II) comprising p-xylylenediamine and/or hexamethylenediamine, and the dicarboxylic acid component (b) comprising 70 mol % or more of adipic acid; and
1 to 30 parts by mass of at least one nucleating agent for crystallization (B) selected from the group consisting of an inorganic nucleating agent and an organic nucleating agent, the inorganic nucleating agent being a talc powder or a ceramic particle, and the organic nucleating agent being a crystalline resin having a half-crystallization time of 30 sec or less when measured at -160° C. by depolarized light intensity method.
The present invention further provides a polyamide resin composition comprising:
100 parts by mass of a copolyamide resin (A′) which is produced by polycondensing a diamine component (a′) comprising 70 to 100 mol % of a diamine component (I′) and 30 to 0 mol % of a diamine component (II′) with a dicarboxylic acid component (b), the diamine component (I′) comprising 30 to 90 mol % of trans-1,4-bis(aminomethyl)cyclohexane and 70 to 10 mol % of cis-1,4-bis(aminomethyl)cyclohexane with the combined molar percentages of the cis-trans isomers being 100 mol %, the diamine component (II′) comprising a diamine excluding both p-xylylenediamine and hexamethylenediamine, and the dicarboxylic acid component (b) comprising 70 mol % or more of adipic acid; and
1 to 30 parts by mass of at least one nucleating agent for crystallization (B) selected from the group consisting of an inorganic nucleating agent and an organic nucleating agent, the inorganic nucleating agent being a talc powder or a ceramic particle, and the organic nucleating agent being a crystalline resin having a half-crystallization time of 30 sec or less when measured at 160° C. by depolarized light intensity method.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the diamine component (a) for the copolyamide resin (A) contains 70 to 100 mol % of a diamine component (I) comprising 30 to 70 mol % of trans-1,4-bis(aminomethyl)cyclohexane (hereinafter referred to as “trans-BAC”) and 70 to 30 mol % of cis-1,4-bis(aminomethyl)cyclohexane (hereinafter referred to as “cis-BAC”) with the combined molar percentages of the cis-trans isomers being 100 mol %.
1,4-Bis(aminomethyl)cyclohexane has a cis-isomer and a trans-isomer.
The molar ratio of the isomers (trans/cis) in the diamine component (I) for the copolyamide resin (A) is 70/30 to 30/70. When the diamine component (a) comprises only the diamine component (I) and the dicarboxylic acid component (b) is adipic acid, the molar ratio of the isomers (trans/cis) is preferably 70/30 to 45/55. A polyamide resin composition comprising a copolyamide resin (A) obtained by polycondensation of a dicarboxylic acid component (b) with a diamine component (I) having a molar ratio of the isomers in the above range, and a specific amount of a nucleating agent for crystallization (B) provides a shaped article excellent in the retention of rigidity at a high temperature condition, the durability under a high temperature condition and the retention of mechanical properties after water-absorption.
The diamine component (a) contains 30 to 0 mol % of the diamine component (II) comprising p-xylylenediamine and/or hexamethylenediamine. As compared with a copolyamide resin (A) prepared using none of p-xylylenediamine and hexamethylenediamine, a copolyamide resin (A) prepared by polycondensation using the diamine component (II) shows a specifically shortened half-crystallization time when measured at 160° C. by depolarized light intensity method. Therefore, a polyamide resin composition prepared by blending the copolyamide resin (A) prepared using the copolymerizable diamine component (II) with at least one nucleating agent for crystallization (B) selected from the inorganic and organic nucleating agents is promoted in its crystallization in the molding process, thereby facilitating the reduction of the molding cycle.
In the present invention, the crystallization speed is expressed, as an indication, by the half-crystallization time measured at 160° C. by depolarized light intensity method. A shorter half-crystallization time means a higher crystallization speed. The measurement of the half-crystallization time by depolarized light intensity method was carried out according to the methods described in “Kobunshi Kagaku”, Vol. 29, No. 323, pp. 139-143 (March, 1972) and “Kobunshi Kagaku”, Vol. 29, No. 325, pp. 336-341 (March, 1972).
Specifically, the half-crystallization time was determined by measuring the time (sec) required until the depolarized light intensity I during the constant-temperature crystallization of a molten specimen reached the value represented by the following formula (2):
I
1/2
=I
0
&plu
Hayashi Takeo
Takano Takahiro
Yamamoto Koji
Antonelli Terry Stout & Kraus LLP
Mitsubishi Gas Chemical Co. Inc.
Woodward Ana
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