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...
Patent
1997-09-08
2000-05-16
Michl, Paul R.
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...
524456, C08K 310
Patent
active
060638486
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition comprising of plural fibrous fillers, or a fibrous filler and a particulate filler, and liquid crystal polymer. More particularly, the present invention relates to molding with extremely low coefficient of linear expansion produced from the liquid crystal polymer composition.
2. Description of Related Art
Liquid crystal polymers which can form anisotropic melting phase are materials known to have low coefficient of linear expansion among thermoplastic resins. Recently, however, for high accuracy, labor saving, reduction of weight, reduction of cost, the requirements have been becoming stricter in the field of electrical and electronic field. With improvement of adhesive technique between resin parts and metallic ones, such resin parts have been often used with metallic parts. Under the circumstances, there are demand for thermoplastic resins having coefficient of linear expansion similar to that of thermoset resins or metal. Liquid crystal polymer, which is a material having lower coefficient of linear expansion for thermoplastic resins, and has higher coefficient of linear expansion in the direction perpendicular to flow compared with that in the direction of flow due to its properties, and is a highly anisotropic material. It is extremely difficult to reduce anisotropy as well as coefficient of linear expansion. Therefore, few studies have centered on reduction of coefficient of linear expansion.
DISCLOSURE OF THE INVENTION
SUMMARY OF THE INVENTION
Considering the above problems, the present inventors have studied intensively on materials having excellent properties as materials with less anisotropy and low coefficient of linear expansion. As the results, we have found that a composition comprising of liquid crystal polymer and two or more specific fillers can provide materials with lower coefficient of linear expansion without significantly deteriorating mechanical properties. Thus, we have attained the present invention.
That is, the present invention provides a liquid crystal polymer composition which comprises 100 parts by weight of a liquid crystal polymer (A), a fibrous filler (B) having an average fiber diameter of 0.1 to 8.0 .mu.m and an average aspect ratio of at least 3, and a fibrous filler (C) having an average fiber diameter of 8.5 to 20.0 .mu.m and average aspect ratio of 40 or below, the total amount of the components (B) and (C) being 100 to 240 parts by weight, and the ratio of the component (B) to the component (C) being 1:3 to 3:1.
In addition, the present invention provides a liquid crystal polymer composition which-comprises 100 parts by weight of a liquid crystal polymer (A), fibrous filler (B) having an average fiber diameter of 0.1 to 8.0 .mu.m and an average aspect ratio of at least 3, and a particulate filler (D) having an average particle diameter of 100 .mu.m or below, the total amount of the components (B) and (D) being 100 to 240 parts by weight, and the ratio of the component (B) to the component (D) being 1:3 to 3:1.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be illustrated in detail.
A liquid crystal polymer (A) used in the present invention means melt-fabricable polymer which can form optically anisotropic melting phase.
The characteristics of anisotropic melting phase can be confirmed by the conventional polarization assay utilizing rectangular polarizers. More particularly, anisotropic melting phase can be confirmed using Leitz polarization microscope by observing molten sample mounted on a Leitz hot stage under an atmosphere of nitrogen at 40.times. magnifications. Liquid crystal polymer applicable to the present invention exhibits optical anisotropy upon examination between rectangular polarizers, wherein polarized light generally permeates even if in a melting static state.
The aforementioned liquid crystal polymer (A) is not particularly limited, but preferably aromatic polyester or aromatic polyester amide. Polyester which partially
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Kobayashi Kazuhito
Murakami Haruji
Michl Paul R.
Polyplastics Co. Ltd.
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