Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2001-01-08
2002-05-14
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S176000, C528S191000, C528S193000, C528S194000, C528S195000, C528S206000, C528S208000, C528S210000, C525S437000, C524S081000
Reexamination Certificate
active
06388045
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a liquid crystalline polymer, a liquid crystalline polymer composition and a molded article made of the same.
BACKGROUND ART
In these days, demands for high performance plastics are more and more increasing and novel polymers with a variety of functions have been developed. Among those plastics, liquid crystalline polymers which exhibit optical anisotropy have draw the attention because of their excellent mechanical properties. Especially, a liquid crystalline polymer consisting of aromatic polyester which is mainly made up of dominantly parahydroxy benzoic acid or derivatives thereof, is excellent in mechanical and electrical properties as well as in heat resistance and thermal stability, and said liquid crystalline polymer has been applied for a variety of products such as machine components, electric and electronic components, automobile parts and table wears.
The molecules of such liquid crystalline polymer as above are easily oriented with even slight shear strength such as occurred in the injection molding process.
Accordingly, there are some problems in a molded article, such as that difference of the mold shrinkage between in the machine direction (ME)) parallel to a material's flow in molding and the transverse direction (TD) to the MD, that has high anisotropy in mechanical strength, and that poor strength at the weldline when the article has a weldline.
In order to eliminate the anisotropy at molding, the arts have proposed various methods.
For example, Japanese Patent Publication (KOKOKU) No. 38007/1993 discloses a method for preparation of aromatic polyesters by polycondensing certain compounds, characterized in that compounds having polyfunctional groups such as 1,3,5-trihydroxy benzene, 3,5-dihydroxy benzoic acid, 5-hydroxy isophthalic acid or functional derivatives thereof are added to the reaction system. Japanese Patent Publication No. 38007/1993 teaches that 1,3,5-trihydroxy benzene and the others have less steric hindrance, are highly reactive and are the materials which can provide a polymer with good thermal stability, and that the aromatic polyester obtained by the method exhibits improved molding properties and less anisotropy.
In addition, Japanese Patent Application Laid Open (KOKAI) No, 331275/1993 discloses to improve the weld strength of the polyester resin by adding whisker consisting of needle-like titanium oxide or needle-like aluminum borate thereto.
However, the weld strength improvement effects in the liquid crystalline resins made by the methods as above were not enough and there were another problem that the flowability of the resin was much declined.
Accordingly, the object of the present invention is to dissolve the above-described problems and to provide a liquid crystalline polymer excellent in heat resistance, molding properties, flow properties and mechanical properties, especially to provide a liquid crystalline polymer which can provide a molded article with improved weld strength and less anisotropy in the molding properties.
The present inventors have studied intensively to dissolve the above problems and found that a liquid crystalline polymer made up of certain polyfunctional aromatic monomers can be used to provide a molded article with improved weld strength and less anisotropy.
DISCLOSURE OF INVENTION
The present invention provides a liquid crystalline polymer, that is a polymer suitable for melt processing, the main chains of the polymer are regularly aligned in parallel directions to give anisotropic melt phase. The polymer has an optically anisotropic property.
Accordingly, the present invention provide a liquid crystalline polymer which is obtained by copolymerizing at least one polyfunctional aromatic monomer selected from the group consisting of the compounds represented by the general formulae (I), (II) and (III) below:
wherein Z represents —NH—A—NH— or —O—A′—O—, wherein A and A′ is an optionally substituted hydrocarbon group of 1-20 carbon atoms which may have a heterocyclic moiety, or a heterocyclic group;
R and R′ may be the same or different and represent a hydrogen atom or a hydrocarbon group of 1-20 carbon atoms;
Y and Y′ may be the same or different and each represents a hydroxy group or a reactive derivative thereof;
Q and Q′ each represents an optionally branched alkyl or alkoxy group of 1-6 carbon atoms, a halogen atom, a nitro group or a nitroso group; and
m and m′ each represents an integer of 0-3
wherein X represents an optionally substituted hydrocarbon group of 1-20 carbon atoms which may have a heterocyclic moiety, or a heterocyclic group;
R
1
, R
2
, R
3
and R
4
may be the same or different and each represents a hydrogen atom or a hydrocarbon group of 1-20 carbon atoms;
Q and Q′ each represents an optionally branched alkyl or alkoxy group of 1-6 carbon atoms, a halogen atom, a nitro group or a nitroso group; and
m and m′ each represents an integer of 0-3; with at least one polymerizable monomer.
In the present invention, examples of the hydrocarbon group of 1-20 carbon atoms in the definitions of A, A′ and X include alkylene groups, alkenylene groups, and arylene groups such as phenylene and biphenylene groups.
Examples of the hydrocarbon group of 1-20 carbon atoms in the definition of R and R′ include alkyl groups of 1-6 carbon atoms, especially methyl and ethyl groups, benzyl group, phenyl group and phenacyl group.
The reactive derivative of hydroxy group in the definition of Y and Y′ may be any which can form an ester.
In the following illustration of the present invention, the at least one compound selected from polyfunctional aromatic monomers represented by the general formulae (I), (II) and (III) will be represented as {circle around (1)}.
The at least one polymerizable monomer used in the liquid crystalline polymer of the present invention may be any of the monomers used in conventional liquid crystalline polymers. Examples of the preferable monomers are those described in the {circle around (2)}-{circle around (5)} below.
{circle around (2)}: at least one compound selected from aromatic dicarboxylic acids;
{circle around (3)}: at least one compound selected from aromatic diols;
{circle around (4)}: at least one compound selected from aromatic hydroxycarboxylic acids; and
{circle around (5)}: at least one compound selected from the group consisting of aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids.
In a preferred embodiment of the present invention, the liquid crystalline polymer of the present invention may be consisting of the combination of following A)-G):
A) a polyester consisting of {circle around (1)}, {circle around (2)} and {circle around (3)};
B) a polyester consisting of {circle around (1)} and {circle around (4)};
C) a polyester consisting of {circle around (1)}, {circle around (2)}, {circle around (3)} and {circle around (4)};
D) a polyester consisting of {circle around (1)}, {circle around (3)} and {circle around (4)};
E) a polyesteramide consisting of {circle around (1)}, {circle around (3)}, {circle around (4)} and {circle around (5)};
F) a polyesteramide consisting of {circle around (1)}, {circle around (2)}, {circle around (4)} and {circle around (5)}; and
G) a polyesteramide consisting of {circle around (1)}, {circle around (2)}, {circle around (3)}, {circle around (4)} and {circle around (5)}.
Further, the liquid crystalline polymer of the present invention may be the one obtained by copolymerizing the above described components with one or more compounds selected from the group consisting of an alicyclic dicarboxylic acid, an alicyclic diol, an aliphatic diol, an aromatic thiol carboxylic acid, an aromatic dithiol, and an aromatic thiol phenol.
Examples of the compounds suitable as monomers used for preparation of the liquid crystalline polymer of the present invention are described below.
The polyfunctional aromatic monomer of {circle around (1)} is the compound represented by the formulae (I), (II) or (III). Particularly,
Asahara Motoki
Hamasaki Taihei
Kitayama Masaya
Kometani Kiichi
Ueno Ryuzo
Acquah Samuel A.
Kabushiki Kaisha Ueno Seiyaku Oyo Kenkyujo
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