Compositions – Liquid crystal compositions
Reexamination Certificate
2002-03-27
2004-09-28
Wu, Shean C. (Department: 1756)
Compositions
Liquid crystal compositions
C428S357000, C106S415000
Reexamination Certificate
active
06797198
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a liquid crystal polymer composition containing a specific plate-shaped filler. More specifically, it relates to a liquid crystal polymer composition which has an excellent low warp and is advantageously used in particular as a connector or the like requiring a low warp after molding and during reflow heating.
PRIOR ART
A liquid crystal polymer capable of forming an anisotropic molten phase has been known to be, among thermoplastic resins, a material which is excellent in dimensional accuracy and damping property and generating little flash during molding. A liquid crystal polymer composition reinforced with glass fibers upon making use of such characteristics has been often employed so far as an SMT-adapted connector. In recent years, however, a connector has been further reduced in weight, thickness and size, and such problems have arisen that warp deformation occurs after molding and during reflow heating owing to an unsatisfactory rigidity caused by an insufficient thickness of a molded article or an internal stress caused by inserting metallic terminals, which results in defective soldering with a substrate. That is, the ordinary reinforcement with glass fibers only has been problematic in that when amounts of glass fibers are increased for enhancing a rigidity, a thin portion is not filled with a resin and terminals inserted are deformed due to a pressure in molding. Thus, materials that can solve all these problems have not existed.
DISCLOSURE OF THE INVENTION
In view of the foregoing problems, the present inventors have assiduously conducted investigations on materials having an excellent low warp, and have consequently found that by compounding a specific amount of a specific plate-shaped filler with a liquid crystal polymer a low warp can be improved without notably decreasing mechanical properties. This finding has led to the completion of the invention.
That is, the invention is to provide a liquid crystal polymer composition in which 5 to 100 parts by weight of a plate-shaped filler (B) satisfying the following formulae (1) and (2) and having an average particle diameter of 0.5 to 100 &mgr;m are compounded with 100 parts by weight of a liquid crystal polymer (A).
D/W
≦5 (1)
3
≦W/H
≦200 (2)
The invention is a composition comprising (A) and (B)
DETAILED DESCRIPTION OF THE INVENTION
The invention is described in detail below. The liquid crystal polymer (A) used in the invention refers to a melt-processible polymer capable of forming an optically anisotropic molten phase. Properties of an anisotropic molten phase can be identified by an ordinary polarization detecting method using crossed polarizers. More specifically, identification of an anisotropic molten phase can be performed by observing a molten sample put on a Leitz hot stage in a nitrogen atmosphere at 40× magnification using a Leitz polarizing microscope. The liquid crystal polymer which can be applied to the invention usually transmits polarized light even in a molten stationary state in the examination between crossed polarizers, optically exhibiting an anisotropy.
The liquid crystal polymer (A) is not particularly limited. An aromatic polyester or an aromatic polyester amide is preferable, and a polyester partially containing an aromatic polyester or an aromatic polyester amide in the same molecular chain is also included in its range. Those having an inherent viscosity (I.V.) of, preferably at least approximately 2.0 dl/g, more preferably 2.0 to 10.0 dl/g when dissolved in pentafluorophenol at 60° C. in a concentration of 0.1% by weight are used.
The aromatic polyester or the aromatic polyester amide as the liquid crystal polymer (A) which can be applied to the invention is especially preferably an aromatic polyester or an aromatic polyester amide containing, as a constituent, at least one compound selected from the group consisting of an aromatic hydroxycarboxylic acid, an aromatic hydroxyamine and an aromatic diamine.
Specific examples thereof include
(1) a polyester mainly comprising at least one of an aromatic hydroxycarboxylic acid and derivatives thereof;
(2) a polyester mainly comprising (a) at least one of an aromatic hydroxycarboxylic acid and derivatives thereof, (b) at least one of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and derivatives thereof and (c) at least one of an aromatic diol, an alicyclic diol, an aliphatic diol and derivatives thereof;
(3) a polyester amide mainly comprising (a) at least one of an aromatic hydroxycarboxylic acid and derivatives thereof, (b) at least one of an aromatic hydroxyamine, an aromatic diamine and derivatives thereof and (c) at least one of an aromatic dicarboxylic acid, analicyclic dicarboxylic acid and derivatives thereof; and
(4) a polyester amide mainly comprising (a) at least one of an aromatic hydroxycarboxylic acid and derivatives thereof, (b) at least one of an aromatic hydroxyamine, an aromatic diamine and derivatives thereof, (c) at least one of an aromatic dicarboxylic acid, analicyclic dicarboxylic acid and derivatives thereof and (d) at least one of an aromatic diol, an alicyclic diol, an aliphatic diol and derivatives thereof. Further, a molecular weight modifier may be used in combination with the foregoing components.
Preferable examples of the specific compounds constituting the liquid crystal polymer (A) which can be applied to the invention include aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; aromatic diols such as 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl, hydroquinone, resorcin and compounds represented by the following formulae (I) and (II); aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid and compounds represented by the following formula (III); and aromatic diamines such as p-aminophenol and p-phenylenediamine.
An especially preferable liquid crystal polymer (A) which is applied to the invention is an aromatic polyester amide containing p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid and p-aminophenol as main structural unit components.
In order to attain the low warp aimed at by the invention, it is required to compound 5 to 100 parts by weight of a specific plate-shaped filler (B) with 100 parts by weight of the liquid crystal polymer (A).
The plate-shaped filler (B) used in the invention has to satisfy the following formulae (1) and (2). That is, it refers to a disk-shaped, square plate-shaped, rectangular plate-shaped or indefinite plate-shaped material which has dimensions in two directions but not in the remaining one direction. Its average particle diameter is 0.5 to 100 &mgr;m.
D/W
≦5 (1)
3
≦W/H
≦200 (2)
wherein D is the maximum particle diameter of the plate-shaped filler (B), the direction of the diameter D is defined as x, W is a particle's diameter which is in the direction y at the right angle to the direction x, and H is a thickness of the particle in the direction z which is vertical to the xy-plane.
Specific examples of such a plate-shaped filler include talc, mica, kaolin, clay, graphite, vermiculite, silicates such as calcium silicate, aluminum silicate and feldspar powder, Japanese acid clay, agalmatolite clay, sericite, sillimanite, bentonite, glass flake, slate powder and silane; carbonates such as calcium carbonate, chalk, barium carbonate, magnesium carbonate and dolomite; sulfates such as barite powder, precipitated calcium sulfate, calcined gypsum and barium sulfate; hydroxides such as hydrated alumina; oxides such as alumina, antimony oxide, magnesia, titanium oxide, zinc oxide, silica, siliceous sand, quartz, white carbon and diatomaceous earth, sulfides such as molybdenum disulfide; substances comprising the materials such as plate-shaped wollastonite and metallic powders.
Of these, talc, mica, kaolin, clay and graphite are preferable in view
Miyashita Takayuki
Ohshiba Hirokazu
Ohtake Mineo
Burns Doane Swecker & Mathis L.L.P.
Polyplastics Co. Ltd.
Sadula Jennifer R.
Wu Shean C.
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