Abstract:
Disclosed is a process for the purification of aromatic dicarboxylic acids in which the salt of an aliphatic diamine and an aromatic dicarboxylic acid is formed in an aqueous solvent, recrystallized, and contacted with an aliphatic dicarboxylic acid in an aqueous solvent such that the aromatic dicarboxylic acid is recoverable in the form of a purified precipitate. The remaining aqueous solute is a salt of the aliphatic diamine and aliphatic dicarboxylic acid and can be used as a starting material in the manufacture of certain polyamides (nylons). The invention is particularly applicable for purifying 2,6-naphthalene dicarboxylic acid, which is difficult otherwise to purify.
Abstract:
Novel thermotropic liquid crystalline polyesters derived from t-butylhydroquinone, terephthalic acid, 2,6-naphthalene dicarboxylic acid and 4-hydroxybenzoic acid are described. These polymers are useful as molding resins.
Abstract:
Use of surfactant in coating of yarn from anisotropic melt-forming polyester with alkali metal salts enhances heat-strengthening acceleration effect.
Abstract:
Films, sheets or foils are given a gas-barrier coating of an aromatic polyamide, polyimide, polyamide-imide, polyhydrazide, polyamide-hydrazide, or polyazomethine by direct vapor-phase condensation polymerization of their respective monomers. The monomers are introduced in an inert diluent gas, mixed and reacted in the presence of the surface to be coated. The surface is maintained above the critical minimum deposition temperature of the monomers but below about 300.degree. C. The coating is formed to a thickness between about 0.1 and 0.6 mil.
Abstract:
A sheet comprising thermoplastic polymer (TP) and short high tensile modulus fibers, in which the concentration of TP in the middle of the sheet is higher than at the surface of the sheet, useful for making prepregs with a thermoset resin.
Abstract:
This invention relates to thermotropic liquid crystalline polyester compositions containing recurring units derived from hydroquinone, 4,4'-dihydroxybiphenyl, terephthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-bibenzoic acid, and 4-hydroxybenzoic acid which are characterized as having melting points less than 365.degree. C., breaking elongations greater than or equal to 1.5%, and heat distortion temperatures greater than 200.degree. C.This invention further relates to the same compositions containing 20 to 40 weight percent of at least one glass reinforcing/filling agent and which are characterized as having melting points less than 365.degree. C., breaking elongations greater than or equal to 1.8%, and heat distortion temperatures greater than 230.degree. C.The compositions are useful as films, fibers, and shaped or molded articles.
Abstract:
This invention relates to thermotropic liquid crystalline polyester compositions containing recurring units derived from 2-methylhydroquinone, terephthalic acid, 2,6-napthalenecarboxylic acid, and hydroquinone, characterized as having a heat distortion temperature of greater than 200.degree. C. and improved elongation. The inclusion of a reinforcing/filling agent selected from the group consisting of glass reinforcing agents, glass fillers, carbon metasilicate, calcium carbonate, talc, titanium dioxide, and calcined aluminum silicate in said compositions, and also in those same compositions lacking recurring units of hydroquinone, results in an improvement in the elongation of said compositions. The inclusion of carbon fiber into these compositions results in no significant decrease in the elongation of said compositions. The compositions are useful as films, fibers, and shaped articles.
Abstract:
This invention relates to thermotropic liquid crystalline polyester compositions containing recurring units derived from hydroquinone, 4-4'-dihydroxybiphenyl, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 4-hydroxybenzoic acid which are characterized as having melting points less than 365.degree. C., breaking elongations greater than or equal to 1.5%, and heat distortion temperatures greater than 200.degree. C.This invention further relates to the same compositions containing 20 to 40 weight percent of at least one glass reinforcing/filling agent and which are characterized as having melting points less than 365.degree. C., breaking elongations greater than or equal to 2.0%, and heat distortion temperatures greater than 230.degree. C.The compositions are useful as films, fibers, and shaped or molded articles.
Abstract:
This invention relates to liquid crystalline polymers (LCPs) derived from (I) hydroquinone and/or 4,4'-biphenol and/or bis(4-hydroxylphenyl) ether, (II) terephthalic acid, (lII) 2,6-naphthalene dicarboxylic acid and/or 4,4'-bibenzoic acid, (IV) 4-hydroxybenzoic acid, (V) 6-hydroxy-2-naphthoic acid, and optionally (VI) an aliphatic diol in specified ratios. In addition to forming exceptionally tough films, the LCPs are useful as molding resins or for blending with other thermoplastic polymers.
Abstract:
The heat resistance of polyester liquid crystalline polymers containing repeat units in selected ratios derived from hydroquinone, 4,4'-biphenol, terephthalic acid, 4-hydroxybenzoic acid, and one or both of 4,4'-bibenzoic acid and 2,6-naphthalene dicarboxylic acid is improved by the addition thereto of 15 to 3000 ppm of an alkali metal or 50 to 3000 ppm magnesium or calcium.