Liquid crystal polyester resin

Details Liquid crystal polyester resin Liquid crystal polyester resin

2001-12-14

2004-10-12

Huff, Mark F. (Department: 1756)

Compositions

Liquid crystal compositions

C252S299630, C252S299670, C349S183000

Reexamination Certificate

active

06802989

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a liquid crystal polyester. More specifically, it relates to a liquid crystal polyester resin having excellent colorability, improved heat resistance and high mechanical properties.
DESCRIPTION OF THE PRIOR ART
A thermotropi liquid crystal polyester resin (to be referred to as “liquid crystal polyester resin” or abbreviated as “LCP” hereinafter) is increasingly used in not only molded articles but also fibers and films due to its excellent mechanical properties such as heat resistance and stiffness, chemical resistance and dimensional stability. Particularly in information and communication fields such as personal computers and portable telephones, parts are becoming more highly integrated, smaller in size and thickness, and lower in height rapidly, there are many cases where an extremely thin portion having a thickness of 0.5 mm or less is formed, and the consumption of the liquid crystal polyester resin is greatly expanding due to its characteristic properties such as excellent moldability, that is, flowability and the formation of no flash which is not seen in other resins.
Meanwhile, many proposals have been made for further improvement of suchproperties as flowability, heat resistance and mechanical properties at the time of polymerization of a liquid crystal polyester resin composition. JP-A 8-511573 (the term“JP-A” as used herein means an“unexamined published Japanese patent application”) discloses a liquid crystal polyester resin composition which is produced by containing an alkali metal in a specific monomer and copolymerizing it and has improved heat resistance.
However, there is still room for the improvement of color uniformness and color strength on coloring the liquid crystal polyester resin composition by a colorant such as carbon black or azo pigment and use thereof in fields that require color uniformness and color strength on coloring is limited.
Then, a liquid crystal polyester resin which has excellent colorability, improved heat resistance and high mechanical properties has been desired.
SUMMARY OF THE INVENTION
The inventors of the present invention have conducted intensive studies and have found that a liquid crystal polyester resin having excellent colorability, improved heat resistance and high mechanical properties is obtained by copolymerizing a trace amount of 4-hydroxyisophthalic acid and/or salicylic acid with another polymerizable monomer and containing a specific amount of an alkali metal ion in the copolymer. The present invention has been accomplished based on this finding.
That is, the present invention provides a liquid crystal polyester resin which comprises 1 to 500 mmol % of a recurring unit derived from 4-hydroxyisophthalic acid and/or salicylic acid as a comonomer and 10 to 5,000 ppm in terms of an alkali metal of an alkali metal compound. This resin is a liquid crystal polyester resin which has excellent colorability, improved heat resistance and high mechanical properties and solves the above problems.


REFERENCES:
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patent: 5124477 (1992-06-01), Suzuki et al.
patent: 5198572 (1993-03-01), White et al.
patent: 5397502 (1995-03-01), Waggoner et al.
patent: 5891532 (1999-04-01), Furuta et al.
patent: 5977405 (1999-11-01), Samuels et al.
patent: 6300459 (2001-10-01), Kaneko et al.
patent: 0 380 286 (1990-08-01), None
patent: 08 511573 (1996-12-01), None
patent: A-8-511573 (1996-12-01), None
patent: WO 94 29366 (1994-12-01), None

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