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
2001-02-16
2001-11-06
Yoon, Tae H. (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...
C524S450000, C524S451000, C524S493000, C524S514000, C428S474400, C428S475500
Reexamination Certificate
active
06313209
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a polyamide resin composition and a film produced from the same, and more particularly, it relates to a polyamide resin composition suitable as resin for production of films, and a film having not only excellent transparency and slip property, but also mechanical properties.
Polyamide resins have been extensively used in various applications such as packages, e.g., food packaging materials and medical packaging materials, and containers because these resins are excellent in strength, flexibility, transparency, heat resistance, chemical resistance, gas-barrier property or the like. When used in these applications, the polyamide resins are molded into a desired shape by various methods.
The films used in the above-described applications are required to have excellent transparency and slip property. Therefore, various studies have been made to obtain films capable of satisfying these requirements. However, conventional polyamide films having an enhanced transparency are deteriorated in slip property between surfaces thereof, resulting in occurrence of blocking. On the contrary, those films having a good slip property are deteriorated in transparency.
As conventional polyamide resins for films, for example, in Japanese Patent Application Laid-Open (KOKAI) No. 51-34256, there is described a polyamide composition containing talc treated with a surfactant. Also, in Japanese Patent Application Laid-Open (KOKAI) No. 9-40862, there is described a polyamide resin composition containing a polyamide which is terminal-modified with hydrocarbon group, and an inorganic filler. However, when these resin compositions are formed into films by air-cooling tubular process, it is difficult to obtain such films satisfying both slip property and transparency.
Further, for example, in Japanese Patent Publication (KOKOKU) No. 51-28307, there is described the polyamide composition containing organophilic bentonite and inorganic fine particles having an average particle size of not more than 2 &mgr;m. However, when the resin composition is formed into films by the air-cooling tubular process, the obtained films are deteriorated in slip property in spite of excellent transparency.
As a result of the present inventors'earnest studies to solve the above problem, it has been found that a film produced from a polyamide resin composition containing at least two kinds of fillers having different average particle sizes from each other and specific particle size distribution is excellent in transparency, slip property and mechanical properties. The present invention has been attained on the basis of this finding.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a polyamide resin composition suitable for the production of films exhibiting not only excellent transparency and slip property but also excellent mechanical properties, and a film produced from the polyamide resin composition.
To attain the above aim, in the first aspect of the present invention, there is provided a polyamide resin composition comprising 100 parts by weight of a polyamide resin and 0.001 to 2 parts by weight of at least two kinds of fillers having different average particle sizes from each other,
an average particle size of a filler having minimum average particle size in said at least two kinds of fillers being 0.001 to 2 &mgr;m,
an average particle size of a filler having maximum average particle size in said at least two kinds of fillers being more than 2 &mgr;m and not more than 15 &mgr;m,
said at least two kinds of fillers having the following particle size distribution.
(a) 20 to 90% by weight of a filler having a particle size of not more than 2 &mgr;m,
(b) 0 to 15% by weight of a filler having a particle size of more than 2 &mgr;m and less than 3 &mgr;m, and
(c) 10 to 80% by weight of a filler having a particle size of not less than 3 &mgr;m.
In the second aspect of the present invention, there is provided a film comprising a polyamide resin composition comprising 100 parts by weight of a polyamide resin and 0.001 to 2 parts by weight of at least two kinds of fillers having different average particle sizes from each other,
an average particle size of a filler having minimum average particle size in said at least two kinds of fillers being 0.001 to 2 &mgr;m,
an average particle size of a filler having maximum average particle size in said at least two kinds of fillers being more than 2 &mgr;m and not more than 15 &mgr;m,
said at least two kinds of fillers having the following particle size distribution.
(a) 20 to 90% by weight of a filler having a particle size of not more than 2 &mgr;m,
(b) 0 to 15% by weight of a filler having a particle size of more than 2 &mgr;m and less than 3 &mgr;m, and
(c) 10 to 80% by weight of a filler having a particle size of not less than 3 &mgr;m.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described in detail below.
As the polyamide resins used in the present invention, there may be exemplified those polyamides obtained by polycondensing lactams having a 3 or more-membered ring, polymerizable &ohgr;-amino acids or dibasic acids with diamine. Examples of the polyamides may include polymers of &egr;-caprolactam, aminocaproic acid, enanthlactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, &agr;-pyrrolidone or &agr;-piperidone; polymers obtained by polycondensing a diamine such as hexamethylene diamine, nonamethylene diamine, undecamethylene diamine, dodecamethylene diamine and m-xylylene diamine with a dicarboxylic acid such as terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecane dioic acid and glutaric acid; or copolymers thereof.
Specific examples of the polyamide resins may include nylon 4, nylon 6, nylon 7, nylon 8, nylon 11, nylon 12, nylon 6.6, nylon 6.9, nylon 6.10, nylon 6.11, nylon 6.12, nylon 6T, nylon 6/6.6, nylon 6/12, nylon 6/6T, nylon 6T/6I, nylon MXD6 or the like. These polyamide resins may be used alone or in the form of a mixture of any two or more thereof. Among these polyamide resins, the preferred polyamide resins are nylon 6, copolymerized nylon 6/66 and a mixture of nylon 6 and copolymerized nylon 6/66.
The terminals of the polyamide resins may be capped with carboxylic acid or amine. For the purpose of the terminal-capping, the use of carboxylic acids having 6 to 22 carbon atoms or amines is preferred. As the carboxylic acids usable for the terminal-capping of the polyamide resins, there may be exemplified aliphatic monocarboxylic acids such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid and behenic acid. As the amines usable for the terminal-capping of the polyamide resins, there may be exemplified aliphatic primary amines such as hexyl amine, octyl amine, decyl amine, lauryl amine, myristyl amine, palmityl amine, stearyl amine and behenyl amine; aliphatic diamines such as hexamethylene diamine; and aromatic diamines such as meta-xylene diamine. The amount of the carboxylic acid or amine used for the terminal-capping is in the range of about 20 to 40 &mgr;eq/g.
The polyamide resins used in the present invention preferably have a relative viscosity of 2.0 to 6.5 when measured at 25° C. at a concentration of 1% in 98% sulfuric acid according to JIS K6810. When the relative viscosity is less than 2.0, it may be difficult to mold the polyamide resin due to too small melting viscosity thereof. On the contrary, when the relative viscosity is more than 6.5, the polyamide resin may be insufficient in melt fluidity. The relative viscosity of the polyamide resins used in the present invention is more preferably 2.2 to 6.0.
The filler used in the present invention satisfies the following conditions (a) to (c) when the total amount of filler is 100% by weight.
(a) Content of a filler having a particle size of not more than 2 &mgr;m: 20 to 90% by weight.
(b) Content of a filler having a particle size of more than 2 &mgr;m and less than 3 &mgr;m: 0 to 15% by weight.
(c) Content
Matsui Hiromichi
Morimoto Seiji
Urabe Hiroshi
Conlin David G.
Dike Bronstein Roberts & Cushman IP Group
Hazzard Lisa Swiszcz
Mitsubishi Engineering-Plastics Corporation
Yoon Tae H.
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