Plastic and nonmetallic article shaping or treating: processes – Orienting or aligning solid particles in fluent matrix material
Reexamination Certificate
1998-03-30
2001-08-28
Heitbrink, Jill L. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Orienting or aligning solid particles in fluent matrix material
C264S140000, C264S328100, C524S188000, C524S262000, C524S264000
Reexamination Certificate
active
06280668
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a blended resin composition comprising a thermoplastic resin which does not exhibit anisotropy in a molten state, such as a polyester resin, and a liquid-crystal polyester resin; and a molding thereof. More particularly, it relates to a resin composition as described above which is reduced in delamination and is excellent in mechanical properties; and a molding thereof.
2 Description of Related Art
A liquid-crystal polyester resin capable of forming an anisotropic molten phase is a thermoplastic resin exhibiting many excellent characteristics such as high strength, high rigidity, high heat resistance, excellent moldability due to high melt flow, and so on. However, it has also disadvantages such as anisotropy in the mechanical properties and expensiveness. On the other hand, a thermoplastic resin not forming any anisotropic molten phases is relatively inexpensive and little exhibits anisotropy in the mechanical properties, but is poor in mechanical properties, heat resistance and so on disadvantageously.
Under these circumstances, attempts have been made to use blends of both of the above resins with the purposes of utilizing the advantages of both of the resins and making up for the faults thereof. For example, JP-A 5-70700 and JP-A 5-112709 have proposed processes which comprise extruding a blend comprising a liquid-crystal polyester resin and a thermoplastic resin not forming any anisotropic molten phase under stretching at a temperature at which both of the resins can be melted to thereby prepare a molding material wherein the liquid-crystal polyester resin is present in the form of fibers having a large aspect ratio, and molding this molding material at a temperature at which the thermoplastic resin can be melted but the liquid-crystal polyester resin cannot be melted to thereby form a product of molding wherein the liquid-crystal polyester resin is contained in a fibrous state and therefore acts as a reinforcement.
Further, another process has also been proposed, which comprises injection-molding a blend comprising a liquid-crystal polyester resin and a thermoplastic resin not forming any anisotropic molten phase at a temperature not lower than the fluidization-starting temperatures of both of the resins under specific molding conditions to thereby orient the liquid-crystal polyester resin in a fibrous state, thus giving a product of molding excellent in physical properties such as rigidity, strength and so on.
However, the products of molding produced by the above processes are disadvantageous because they are liable to cause delamination owing to their poor interfacial strength between the liquid-crystal polyester resin and the resin not forming any anisotropic molten phase, and they cannot safely be said to be satisfactory in mechanical strengths.
DISCLOSURE OF THE INVENTION
Summary of the Invention
The present invention aims at providing a resin composition which comprises a liquid-crystal polyester exhibiting anisotropy in a molten state and a thermoplastic resin not exhibiting anisotropy in a molten state, such as a polyester, and which is reduced in delamination and is excellent in mechanical properties; and a molding thereof.
The inventors of the present invention have intensively studied in view of the above problems and have found that the objective composition can be obtained by reducing the delamination of a blend comprising a thermoplastic resin and a liquid-crystal polyester resin by the simultaneous use of a specific silane compound and improving the physical properties, such as rigidity and strength, of the blend by forming the liquid-crystal polyester resin into fibers. The present invention has been accomplished on the basis of this finding.
Namely, the present invention relates to a synthetic resin composition produced by blending 100 parts by weight of a resin component comprising 99 to 50 parts by weight of a thermoplastic resin (a) which does not exhibit anisotropy in a molten state and 1 to 50 parts by weight of a liquid-crystal polyester resin (b) capable of forming an anisotropic molten phase with 0.01 to 3.0 parts by weight of at least one silane compound (c) selected from among vinylalkoxysilanes, aminoalkoxy-silanes and mercaptoalkoxysilanes; and a molding thereof. In short, the present invention relates to a composition comprising the components (a), (b) and (c) which are well blended with each other.
The constitution of the present invention will now be described in detail.
DETAILED DESCRIPTION OF THE INVENTION
The thermoplastic resin which does not exhibit anisotropy in a molten state to be used in the present invention as the component (a) may be any conventional thermoplastic one. However, the use of a polymer resin having an ester, amide, imide, urethane, carboxyl, hydroxyl, amino or mercapto group in the main chain o r at the end(s) is preferable, because it is remarkably effective in reducing the delamination and in improving the mechanical properties. Specific examples of such a resin include polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polycarbonate; polyamides such as nylons 6 and 66; polyimides; polyurethanes; polyphenylene oxide, polysulfone, poly(ether sulfone), poly(ether ether ketone) and polyoxymethylene which have hydroxyl group(s) at the end(s); polyphenylene sulfides having mercapto group(s) at the end(s); and polymethyl methacrylate, polymethyl acrylate and polyvinyl acetate which have ester groups in the main chain; and copolymers comprising two or more of these polymers. Among them, polyester resins are preferable.
The liquid-crystal polyester resin to be used in the present invention as the component (b) is a melt-processable polyester having the property that the polymeric molecular chains take a regular parallel arrangement in the molten state. Such an arranged state of molecules is sometimes called “liquid-crystal state”.
The presence of an anisotropic molten phase can be ascertained by a conventional test with polarized light using crossed nicols. Precisely, it can be ascertained by observing a molten sample put on a Leitz hot stage in a nitrogen atmosphere under a Leitz polarization microscope (40×magnification). When examined between the nicols, the polymer according to the present invention can transmit polarized light even in a static molten state, thus exhibiting optical anisotropy.
Liquid-crystal polyester resins suitably usable in the present invention are substantially insoluble in usual solvents and therefore unfit for solution processing. As described above, however, such polymers can easily be melt-processed by conventional means. The polymer capable of forming an anisotropic molten phase to be used in the present invention is preferably an aromatic polyester, an aromatic polyester amide or a polyester comprising part of both of them in one molecular chain.
Particularly preferably is a liquid-crystal aromatic polyester or polyester amide containing constituent units derived from at least one member selected from the group consisting of aromatic hydroxy carboxylic acids, aromatic hydroxyamines and aromatic diamines.
More specific examples include
1) polyesters prepared mainly from one or more members selected from among aromatic hydroxy carboxylic acids and derivatives thereof;
2) polyesters prepared mainly from
a) one or more members selected from among aromatic hydroxy carboxylic acids and derivatives thereof
b) one or more members selected from among aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof, and
c) one or more members selected from among aromatic diols, alicyclic diols, a liphatic diols and derivatives thereof;
3) polyester amides prepared mainly from
a) one or more members selected from among aromatic hydroxy carboxylic acids and derivatives thereof,
b) one or more members selected from among aromatic hydroxyamines, aromatic diamines and derivatives thereof, and
c) one or more members selected from among aromatic dicarboxylic acids
Ishikawa Takayuki
Saito Tatsuya
Heitbrink Jill L.
McDowell Suzanne E.
Nixon & Vanderhye P.C.
Polyplastics Co. Ltd.
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