Compositions – Liquid crystal compositions
Reexamination Certificate
2001-07-30
2004-06-29
Huff, Mark F. (Department: 1756)
Compositions
Liquid crystal compositions
C252S299670, C252S299640, C252S299620
Reexamination Certificate
active
06755991
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an aromatic dicarboxylic acid composition and a liquid crystalline polyester resin made from the same.
Thermotropic liquid crystalline polyester resins (hereafter, referred as liquid crystalline polyesters or LCPs) are excellent in mechanical properties such as heat resistance and stiffness, chemical resistance and dimensional accuracy. The LCPs are used not only for molded products but also for variety of products including fibers and films. For example, parts used in personal computers and mobile phones are highly integrated and the art wishes to use downsized, thinner and smaller parts. In this field, very thin parts, as thin as 0.5 mm or less of the thickness are sometimes required. Based on the excellent molding properties of the LCPs including good flowability and less flash and warpage development compared to the other thermoplastic resins, consumption of the LCPs has been increasing.
Meanwhile, liquid crystalline polyesters still leave much to be improved in their flowability, heat resistance, and mechanical properties and a variety of proposals have been made. For example, WO 94/29366 discloses a liquid crystalline polyester resin having improved heat resistance prepared by adding alkali metal into certain monomers and polymerizing the same.
However, when colored with a colorant such as carbon black or azo pigment, it is difficult to obtain uniformly colored LCP product. Therefore, application of said LCPs in the field, where uniform solid color or clear color development is required, has been limited.
An object of the present invention is to provide a liquid crystalline polyester resin having an improved heat resistance and good mechanical properties as well as good colorability.
Another object of the present invention is to provide an aromatic dicarboxylic acid composition useful for preparing a liquid crystalline polyester resin having an improved heat resistance and good mechanical properties as well as good coloring properties.
SUMMARY OF THE INVENTION
The present invention relates to a composition essentially consisting of;
(a) at least one aromatic dicarboxylic acid,
(b) 1-3000 ppm of at least one compound selected from the group consisting of 6-formyl-2-naphthoic acid, 6-methoxycarbonyl-2-naphthoic acid and trimellitic acid
(c) 1-1000 ppm of at least one alkaline metal, and
(d) 0-3000 ppm of at least one transition metal.
The composition of the present invention is used for preparing thermotropic liquid crystalline polyester resin. The liquid crystalline polyester resin prepared from the aromatic dicarboxylic acid composition and LCP constituting monomers other than the aromatic dicarboxylic acid is excellent in coloring property and has improved heat resistance as well as good mechanical properties.
The present invention also provides a liquid crystalline polyester resin comprising;
(a) at least one repeat unit derived from an aromatic dicarboxylic acid,
(b) at least one monomer unit derived from a compound selected from the group consisting of 6-formyl-2-naphthoic acid, 6-methoxycarbonyl-2-naphthoic acid and trimellitic acid in an amount of 0.1-100 mmol % based on the total monomer units constituting the polyester; and
(c) 1-100 ppm of at least one alkali metal compound.
The liquid crystalline polyester resin of the present invention may further comprise 1-300 ppm of at least one transition metal.
The liquid crystalline polyester resin of the present invention may be prepared by polymerizing the aromatic dicarboxylic acid composition of the present invention and LCP constituting monomers other than the aromatic dicarboxylic acid. Alternatively, the LCP resin of the present invention may be prepared by mixing LCP constituting monomers with the above-described additives so that the ratio of the additives are in the defined range, and polymerizing the same. Irrespective of the starting material, the liquid crystalline polyester resin comprising the above-defined components in above-defined ranges is encompassed by the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The aromatic dicarboxylic acid composition of the present invention comprises 1-3000 ppm, preferably 5-2500 ppm and more preferably 10-2000 ppm of at least one compound selected from the group consisting of 6-formyl-2-naphthoic acid, 6-methoxycarbonyl-2-naphthoic acid and trimellitic acid.
6-formyl-2-naphthoic acid can be prepared from 6-methoxycarbonyl-2-naphthoic acid by reducing the carboxyl group according to the conventional manner to give formyl group, then hydrolyzing the other methyl ester and purifying the product.
6-methoxycarbonyl-2-naphthoic acid may be prepared from 2,6-naphthalene dicarboxylic acid by dissolving the same in a solvent such as N,N-dimethylformamide, reacting the same with stoichiometrically equal amount of methyl iodide or the like under the presence of potassium carbonate or the like and purifying the reaction product.
Trimellitic acid is commercially available.
The aromatic dicarboxylic acid composition of the present invention comprises 1-1000 ppm, preferably 2-500 ppm and more preferably, 5-300 ppm of at least one alkali metal.
According to the present invention, examples of alkali metals include lithium, sodium, potassium, cesium and rubidium. Preferably, the alkali metal may be sodium, potassium or a mixture thereof, and more preferably potassium.
The aromatic dicarboxylic acid composition of the present invention may further comprise 1-3000 ppm, preferably 1-2000 ppm and more preferably 2-1000 ppm of at least one transition metal.
Examples of transition metals include cobalt, manganese, iron, zinc, nickel and copper. Among the above, cobalt, manganese and iron, and especially, cobalt and manganese are preferable.
Both of the alkali metals and the transition metals may be added to and present in the aromatic dicarboxylic acid composition or the LCP resin of the present invention in the form of compounds such as salts thereof. The metal itself may be present in the form of its cation. Examples of salts include sulfate, carbonate, bicarbonate, nitrate, carboxylate, and halogenate of the alkali metal or the transition metal. Among the above, carboxylate, sulfate and carbonate are preferable. As for carboxylates, salts of aliphatic carboxylic acid having 2-6 carbon atoms and of carboxylic acid which can be incorporated into the LCP as a monomer unit constituting the same are preferable. For example, acetate, 4-hydroxy benzoate, 6-formyl-2-naphthoate, 6-methoxycarbonyl-2-naphthoate, trimellitate, 2-hydroxy-6-naphthoate and salts of other polymerizable monomers from which aromatic carbonyl repeat units can be derived are preferably used.
The volume mean diameters of both of the alkali metal salts and the transition metal salts added to or incorporated in the aromatic dicarboxylic acid composition or the LCP of the present invention may be in the range of 0.01-500 &mgr;m, preferably, 0.05-150 &mgr;m.
According to the present invention, the aromatic dicarboxylic acid may be in the form of its alkyl, alkoxy or halogenated derivatives as well as their ester forming derivatives. Examples of aromatic dicarboxylic acids and their derivatives include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 4,4′-diphenyldicarboxylic acid, bis(4-carboxyphenyl) ether, bis(4-carboxyphenoxy)butane, bis(4-carboxyphenyl) ethane, bis(3-carboxyphenyl)ether and bis(3-carboxyphenyl) ethane. Among the above, terephthalic acid and 2,6-naphthalene dicarboxylic acid, especially, 2,6-naphthalene dicarboxylic acid are preferable.
The method to prepare the aromatic dicarboxylic acid composition of the present invention is not limited. For example, the aromatic dicarboxylic acid may be prepared by, admixing the above-defined amount of components to at least one aromatic dicarboxylic acid and mixing the same uniformly.
The present invention further provides a liquid crystalline polyester resin comprising
(a) at least one repeat unit derived f
Kato Hiroyuki
Kometani Kiichi
Ueda Kazunori
Huff Mark F.
Kabushiki Kaisha Ueno Seiyaku Oyo Kenkyujo
Sadula Jennifer R.
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