Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Hydroentangled nonwoven fabric
Patent
1996-07-15
1997-12-02
Lam, Cathy F.
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Hydroentangled nonwoven fabric
428409, 428480, 428901, 1562726, 1563077, B32B 506, B32B 900, B32B 2706, B32B 3100
Patent
active
056929404
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a printed circuit laminate, and a substrate therefor.
BACKGROUND ART
Hitherto, a material prepared using a glass fabric was generally used as a substrate for a printed circuit laminate. However, there are disadvantages that glass has high dielectric constant and weighs much. A substrate made of aromatic polyamide fibers was proposed for weight-saving, but it had disadvantageously highwater-absorbability.
Further, substrates using liquid crystal polyester fibers which weigh little and have low dielectric constant are disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 62-36892, Japanese Examined Utility Model Publication (Kokoku) No. 5-33023 and Japanese Unexamined Patent Publication (Kokai) No. 3-29387. However, such substrates have poor adhesive properties to thermosetting resin. When a laminate is prepared by impregnating the substrates with thermosetting resin, the thermosetting resin is prone to be peeled from the substrates, and then, the peeled portion absorbs moisture to cause a defect in insulation.
DISCLOSURE OF INVENTION
Accordingly, the object of the present invention is to provide a substrate which remedies the above disadvantages of the prior art, has low dielectric constant, weighs little, has low water-absorbability, properties to be effectively impregnated with thermosetting resin, and excellent adhesive properties to thermosetting resin, and to provide a printed circuit laminate using the same.
Another object of the present invention is to provide a printed circuit laminate having a good workability by a drill in addition to the above excellent properties.
The above objects may be achieved by the present invention relating to a substrate for a printed circuit laminate, characterized by comprising a nonwoven fabric which is composed mainly of a liquid crystal polyester fiber, and which is subjected to treatment"!, and
Further, the present invention also relates to a printed circuit laminate, characterized by containing at least one prepreg prepared by impregnating said substrate with thermosetting resin and then drying.
BEST MODE FOR CARRYING OUT THE INVENTION
The liquid crystal polyester fiber which is used in the present invention may be prepared by spinning liquid crystal polyester resin. The term "liquid crystal polyester resin" used herein means a polymer which can form an anisotropic melt phase. The polymer contains regular and parallel orientations in the molecular chain, is generally elongated and flattened, and has a high stiffness in the direction of the elongated axis of the molecule. The anisotropic melt phase may be easily confirmed, for example, by means of a usual method for measuring deflection using crossed polarizers.
The liquid crystal polyester fiber which may be used in the present invention is not limited so long as it is prepared by spinning the liquid crystal polyester resin. However, fibers from wholly aromatic polyester resin, i.e., polyester resin which has a main chain consisting of aromatic rings as a repeating unit, is preferable. Therefore, fibers from the resin obtained by appropriately combining aromatic diols, aromatic dicarboxylic acids, and/or aromatic hydroxycarboxylic acids are preferable. Particularly, a polyester copolymer of p-hydroxy benzoic acid and 2-hydroxynaphthalene-6-carboxylic acid has a well-balanced properties in spinning property and heat resistance and thus may be preferably used, and a polyester copolymer of p-hydroxy benzoic acid, terephthalic acid and 4,4'-dihydroxybiphenyl has excellent heat resistance, and thus may be preferably used.
Typical aromatic diols, aromatic dicarboxylic acids, and/or aromatic hydroxycarboxylic acids used to obtain the wholly aromatic polyester are as follow:
A compound of the formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are independently hydrogen, halogen, such as chlorine, bromine, iodine or fluorine, alkyl, such as lower alkyl having 1 to 4 carbon atoms, or phenyl optionally substituted with one or more halogen atoms
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Abstract of Japanese Unexamined Patent Publication No. 2-269864 (Nov. 5, 1990).
Abstract of Japanese Unexamined Patent Publication No. 3-35025 (Feb. 15, 1991).
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Kimura Koji
Kinbara Hidenori
Mizoguchi Masanobu
Nozaki Mitsuru
Shimono Naohiko
Japan Vilene Company Ltd.
Lam Cathy F.
Mitsubishi Gas Chemical Company Ltd.
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