Compositions – Liquid crystal compositions
Reexamination Certificate
2002-07-18
2004-07-06
Huff, Mark F. (Department: 1756)
Compositions
Liquid crystal compositions
C403S220000, C285S223000
Reexamination Certificate
active
06758989
ABSTRACT:
This is a national phase filing of International Application No. PCT/JP01/00448, filed Jan. 24, 2001.
TECHNICAL FIELD OF THE INVENTION
The present invention concerns a molded article using a liquid crystal polymer composition blended with a non-fibrous filler and, optionally, a fibrous filler. More in particular, it relates to a liquid crystal polymer composition of excellent less warping property which is particularly suitable for a connector and the like requiring low warp after molding and during reflow heating.
PRIOR ART
A liquid crystal polymer capable of forming an anisotropic molten phase has been known among thermoplastic resins, as a material excellent in dimensional accuracy and damping property and generating extremely little flash during molding. Heretofore, taking advantage of such features, liquid crystal polymer compositions reinforced with glass fibers have generally been adopted as SMT coping connectors. However, since connectors have been reduced in weight, thickness and size in recent years, existent molded articles using reinforcing materials only consisting of glass fibers cause a problem that they are deformed upon reflow to result in soldering failure with substrates due to insufficient rigidity because of the insufficient thickness, the anisotropy of glass fibers and internal stresses caused by pressure upon molding. Further, molded articles, using a reinforcing material only consisting of non-fibrous fillers or a composite filler reinforcing material comprising a non-fibrous filler and a glass fiber, can suppress deformation upon reflow but involves a problem of fracture upon fitting due to insufficient strength of the molded article per se. Thus, molded articles capable of overcoming all of the problems described above have not yet been present.
DISCLOSURE OF THE INVENTION
In view of the foregoing problems, the present inventors have made earnest research and study on materials having excellent characteristics regarding less warping property and mechanical properties and accomplished the invention based on the finding that the less warping property can be obtained without greatly deteriorating the mechanical properties by using a material in which a non-fibrous filler is blended in a specific amount into a liquid crystal polymer and molding the same so as to provide a particular oriented state.
That is, this invention provides a molded article of a liquid crystal polymer composition in which 100 parts by weight of a liquid crystal polymer (A) is blended with 5 to 100 parts by weight of a non-fibrous filler (B) in which a non-fibrous filler is so dispersed that when a diffraction peak of the non-fibrous filler is measured by a reflection method and a transmission method by means of a wide-angle X-ray diffraction, the diffraction peak of the non-fibrous filler that can be recognized by the reflection method can not be confirmed by the transmission method.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is to be explained specifically. The liquid crystalline polymer (A) used in the invention means a melt processable polymer capable of forming an optically anisotropic molten phase. The property of the anisotropic molten phase can be recognized by an ordinary polarization inspection method utilizing crossed polarizers. More specifically, the anisotropic molten phase can be confirmed by using a Leitz polarization microscope and observing a molten specimen placed on a Leits hot stage at a 40× magnification ratio in a nitrogen atmosphere. The liquid crystal polymer applicable to this invention usually permeates a polarized light even in a molten stationary state to exhibit optical anisotropy when inspected between crossed polarizers.
The liquid crystal polymer (A) described above has no particular restriction but is preferably an aromatic polyester or an aromatic polyester amide and also includes those polyesters containing an aromatic polyester or aromatic polyester amide partially in one molecular chain. Those having a inherent viscosity (I. V.) of, preferably, at least about 2.0 dl/g and, further preferably, 2.0 to 10.0 dl/g when dissolved at a concentration of 0.1% by weight in pentafluorophenol at 60° C. are used.
The aromatic polyester or aromatic polyester amide as the liquid crystal polymer (A) employable to this invention is, particularly preferably, an aromatic polyester or aromatic polyester amide having, as the constituent, at least one compound selected from the group consisting of aromatic hydroxycarboxylic acids, aromatic hydroxyamines and aromatic diamines.
More specifically, they include,
(1) polyester mainly comprising at least one of aromatic hydroxycarboxylic acids and derivatives thereof;
(2) a polyester mainly comprising (a) at least one of aromatic hydroxycarboxylic acids and derivatives thereof, (b) at least one of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof, (c) at least one of aromatic diols, alicyclic diols, aliphatic diols and derivatives thereof;
(3) polyester amides mainly comprising (a) at least one of aromatic hydroxycarboxylic acids and derivatives thereof, (b) at least one of aromatic hydroxyamine, aromatic diamine and derivatives thereof, and (c) at least one of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof; and
(4) polyester amide mainly comprising (a) at least one of aromatic hydroxycarboxylic acids and derivatives thereof, (b) at least one of aromatic hydroxyamines, aromatic diamines and derivatives thereof, (c) at least one of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof, and (d) at least one of aromatic diols, alicyclic diols, aliphatic diols and derivatives thereof. Further, a molecular weight controller may optionally be used together with the constituents described above.
Preferred examples of the specific compounds constituting the liquid crystal polymer (A) applicable to this invention can 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 formulas (I) and (II); and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 2,6-naphthalene dicarboxylic acids and compounds represented by the following formula (III); and aromatic amines such as p-aminophenol, and p-phenylene diamine.
The particularly preferred liquid crystal polymer (A) applied to this invention is an aromatic polyester amide comprising-hydroxybenzoicacid, 6-hydroxy-2-naphthoicacid, terephthalic acid and p-aminophenol as the main constituent unit component.
For attaining the less warping property as an object of the invention, it is necessary that 5 to 100 part by weight of a non-fibrous filler (B) has to be dispersed based on 100 parts by weight of the liquid crystal polymer (A) so that when a diffraction peak of the non-fibrous filler is measured by a transmission method and a reflection method by means of a wide-angle X-ray diffraction, the diffraction peak of the non-fibrous filler confirmed by the reflection method is not confirmed by the transmission method. Even if the non-fibrous filler is used, when a molded article is measured by the reflection method and the transmission method by means of the wide-angle X-ray diffractiometry and the diffraction peak of the non-fibrous filler is confirmed also by the transmission method, the non-fibrous filler is not dispersed so as to exhibit the less warping property. For dispersing the non-fibrous filler so that the diffraction peak thereof is no more confirmed by the transmission method, the injection speed during molding is important. If the injection speed is too slow, the non-fibrous filler is not in such a dispersion state that the diffraction peak by the transmission method can not be confirmed. On the other hand, if it is too fast, since it forms an uneven layer by the resin jetting, the dispersion
Miyashita Takayuki
Nakane Toshio
Burns Doane Swecker & Mathis L.L.P.
Huff Mark F.
Polyplastics Co. Ltd.
Sadula Jennifer R.
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