Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2001-08-21
2003-02-04
Chen, Vivian (Department: 1773)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S480000, C428S483000, C528S176000, C528S190000, C528S194000, C528S195000, C528S298000, C528S302000, C528S308000, C528S308600
Reexamination Certificate
active
06514611
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to stretchable anisotropic melt-forming polymers suitable for use in the production of a variety of shaped articles including films, fibers and blow-molded forms. This invention also relates to shaped articles made from such polymers, including multilayer laminates having at least one layer formed from such polymers.
2. Description of the Prior Art
Anisotropic melt-forming polymers, also known as liquid crystalline polymers or “LCPs”, are well known in the art. Anisotropic melt-forming polymers exhibit a parallel ordering of molecular chains in the melt phase and are also termed “thermotropic” liquid crystalline polymers. Many of these materials are wholly aromatic in nature.
Thermotropic polymers include aromatic copolyesters having recurring units derived from p-hydroxybenzoic acid, at least one aromatic diol and at least one aromatic dicarboxylic acid, as well as wholly aromatic copolyesteramides having recurring units derived from p-hydroxybenzoic acid, at least one aromatic diol, at least one aromatic diacid, and aminophenol. Without the inclusion of recurring units that disrupt the crystalline structure, such polymers tend to have very high melting points, for example, 360° C. and above, making them difficult to melt fabricate. Incorporation of recurring units that provide non-parallel or “kinky” linkages is a common means of lowering melting point. These kinky linkages include “meta” or 1,3-aromatic ring structures.
Common materials from which meta linkages are derived include m-hydroxybenzoic acid, isophthalic acid, resorcinol, and m-aminophenol. U.S. Pat. Nos. 4,563,508; 5,037,939; and 5,066,767 disclose polymers containing recurring units derived from p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, hydroquinone and 4,4′-biphenol; U.S. Pat. No. 4,912,193 discloses polymers having recurring units derived from p-hydroxybenzoic acid, 4,4′-biphenol, terephthalic acid and isophthalic acid; U.S. Pat. No. 4,966,956 discloses polymers having recurring units derived from p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, 4,4′-biphenol and aminophenol; U.S. Pat. No. 5,663,276 discloses polymers having recurring units derived from p-hydroxybenzoic acid, terephthalic acid, 4,4′-biphenol, isophthalic acid, hydroquinone and 4,4′-biphenyldicarboxylic acid; U.S. Pat. No. 5,089,594 discloses polymers having recurring units derived from p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, 4,4′-biphenol, and an aromatic diol, for example, hydroquinone; U.S. Pat. No. 4,722,993 discloses polymers having recurring units derived from m-aminophenol, p-hydroxybenzoic acid, terephthalic and/or isophthalic acid, one or more of hydroquinone, 4,4′-biphenol or resorcinol and, if desired, m-hydroxybenzoic acid; U.S. Pat. No. 5,399,656 discloses polymers having recurring units derived from p-hydroxybenzoic acid, terephthalic acid, resorcinol and an aromatic diol, for example, 4,4′-biphenol; U.S. Pat. No. 5,025,082, discloses polymers having recurring units derived from p-hydroxybenzoic acid, terephthalic acid, 4,4′-biphenol, 2,6-naphthalene dicarboxylic acid, and at least one aromatic diol selected from hydroquinone, methylhydroquinone, trimethylhydroquinone, resorcinol and tetramethylbiphenol; and U.S. Pat. No. 5,798,432 discloses polymers having recurring units derived from p-hydroxybenzoic acid, 2,6-naphthalene dicarboxylic acid, terephthalic acid, isophthalic acid, hydroquinone, p-aminophenol and 4,4′-biphenol.
The presence of meta linkages notwithstanding, aromatic polymers derived from p-hydroxybenzoic acid, at least one aromatic dicarboxylic acid and at least one aromatic diol and/or aminophenol, as set forth in the patents noted above, tend to have highly ordered crystalline structures and, although drawable in the melt, generally lack the ability to be stretched to a significant degree at temperatures below the molten state.
Another class of thermotropic polymers have recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, at least one aromatic diacid and at least one aromatic diol. The incorporation of meta linkages into such polymers is described, for example, in the following: U.S. Pat. No. 4,522,974 disclosing polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, hydroquinone and isophthalic and/or terephthalic acid; U.S. Pat. No. 4,920,197 disclosing polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid, isophthalic acid and resorcinol; U.S. Pat. No. 4,937,310 disclosing polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid, isophthalic acid and resorcinol; U.S. Pat. No. 4,918,154 disclosing polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic and/or isophthalic acid, resorcinol and hydroquinone; and U.S. Pat. No. 4,983,713 disclosing polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid, 4,4′-biphenol, and isophthalic acid. The polymers set forth in the examples of these patents tend to have ordered crystalline structures and are not considered to be highly stretchable materials.
More recent patents disclose liquid crystalline polymers that include stretchable materials. U.S. Pat. No. 5,656,714 discloses amorphous and what are termed “semi-crystalline” polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid, 4,4′-biphenol, and resorcinol. Fibers made from the amorphous polymers of Examples I and IX were respectively reported to be drawn to 73 and 30 times their as-spun length. Apart from Examples I and IX, no additional data regarding the stretchability of the exemplified polymers is provided. The polymers exemplified by U.S. Pat. No. 5,656,714 vary in terms of their degree of crystallinity; some, but not all, of these polymers are highly stretchable.
U.S. Pat. Nos. 6,132,884; 6,207,790; and 6,222,000 disclose highly stretchable amorphous anisotropic melt-forming polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, one or more aromatic monomers that provide the resulting polymer with selected meta-linkages, one or more aromatic diacids, and an aromatic diol and/or hydroxyamine, at least a portion of which is biphenol. These patents also disclose stretched articles made from such polymers. According to these patents, in order to produce highly stretchable amorphous anisotropic polymers, it is necessary to provide the polymers with specific recurring units in narrowly defined amounts. The polymers described by all three of these patents are required to contain both meta-linkages and at least about 5 mole percent of recurring units derived from biphenol.
LCPs that are stretchable at lower temperatures have a diverse range of end-use applications. Amorphous LCPs having a Tg (i.e., onset of the glass transition temperature as measured by differential scanning calorimetry or “DSC”) of 150° C. or less that are highly stretchable at temperatures above Tg, but below the temperature at which the LCP is in the molten state, are of particular interest in the production of articles that are stretched, drawn or otherwise processed at lower temperatures. Liquid crystalline polymers that are stretchable at temperatures below the processing temperatures of conventional film-forming polymers, for example, polyolefins or polyalkylene terephthalates such as PBT or PET, may be particularly desirable for use in the production of multilayer articles having one or more layers of such conventional film-forming polymers, for example, films, laminates, blow-molded containers, and the like. In these multi-layer applications, the barrier, mechanical and/or optical properties of liquid crystalline polymers may provide advantages that are typica
Linstid, III H. Clay
Provino Vincent J.
Shepherd James P.
Chen Vivian
Klumas Karen E.
Ticona LLC
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