Abstract: A continuous process for the production of a phenolic-based cyanate ester resin is provided and includes the steps of: feeding a phenolic organic compound, a trialkylamine and a cyanogen halide into a continuous, plug-flow type reactor; causing the reactants to flow through and react in the reactor over a period of time defined as a residence time; continuously reacting the phenolic organic compound, the triallckylamine and the cyanogen halide in the reactor; and maintaining a temperature in the reactor of between about -75.degree. C. to about 0.degree. C. The reactor has a length which is equal to or greater than ten times its internal diameter. The mol equivalent concentration of the cyanogen halide is greater than the mol equivalent concentration of the trialkylamine, and the mol equivalent of the trialkylamine is greater than the mol equivalent of the phenolic organic compound.

Abstract: The present invention is a circuit board having a substrate comprising a semi-IPN and at least one balanced polyaramid layer.

Abstract: A thermotropic polyester carbonate containing aromatic diacyl moieties, aromatic dihydroxy moieties and carbonate moieties, wherein up to 50 mole percent of the aromatic dioxy moieties are replaced with aliphatic dihydroxy moiety, such as 2,2-dimethyl-1,3-propanediol.

Abstract: A process of blending two or more polymers having varying viscosities by blending the polymers in the melt in the presence of a solid particulate material to form polymer blends having improved dispersion of the polymer.

Abstract: Thermotropic poly(ester carbonates) such as the terephthalate/carbonate of a mixture of hydroquinose, resorcinol, tert-butylhydroquinone and methylhydroquinone. With a major proportion of the more readily available hydroquinone and resorcinol, thermotropic properties (liquid crystallinity in the melt) are observed.

Abstract: A thermotropic poly(ester carbonate) containing diacyl moieties such as terephthalate and carbonate moieties as well as dihydroxy-derived moieties is useful for forming fibers or films. The dihydroxy-derived moieties are at least 40% derived from t-butylhydroquinone, with hydroquinone and methylhydroquinone being exemplary second components. The polymers can be prepared by melt, solution or interfacial polymerization, are liquid crystalline in the melt and have glass transition temperatures above 100.degree. C.

Abstract: The subject polymers are novel homopolymers and copolymers. The homopolymers are characterized by relatively high T.sub.g of about 120.degree. C. relative to their T.sub.m of about 250.degree. C., whereby they can readily be fabricated into fibers, films and like structures from the melt, and retain strength above 100.degree. C. The copolymers have T.sub.g 's intermediate between those of the homopolymers of the constituent monomers, and can be fabricated as for the subject homopolymers.Novel processes of obtaining the monomer, p-(1,1-dimethyl-2-hydroxyethyl)benzoic acid, are disclosed.

Abstract: Polycarbonate copolymers from bisphenol-A containing terephthalate moieties constituting 5 or 10 mol percent of the polymer, whereby after long exposure to working temperature the polymer retains Izod impact resistance of at least 9 ft. -lbs. per inch of notch.

Abstract: A process for producing poly(ester carbonates) and polyesters by reacting an aromatic or cycloaliphatic dicarboxylate salt such as sodium terephthalate with phosgene in an organic solvent in the presence of a catalytic amount of a tertiary nitrogen compound such as pyridine, optionally separating the suspended by-product inorganic salt and then interfacially reacting with a bisphenol such as bisphenol A. Excess phosgene in the diacid chloride synthesis can be carried over to the polymerization if a poly(ester carbonate) is to be produced or removed if a polyester is to be produced. Certain low levels of a tertiary nitrogen compound with a pyridine nucleus in the organic solution do not interfere with the interfacial polymerization.

Abstract: The subject polymers are novel homopolymers and copolymers. The homopolymers are characterized by relatively high T.sub.g of about 120.degree. C. relative to their T.sub.m of about 250.degree. C., whereby they can readily be fabricated into fibers, films and like structures from the melt, and retain strength above 100.degree. C. The copolymers have T.sub.g 's intermediate between those of the homopolymers of the constituent monomers, and can be fabricated as for the subject homopolymers.Novel processes of obtaining the monomer, p-(1,1-dimethyl-2-hydroxyethyl)benzoic acid, are disclosed.

Abstract: Poly(ester aromatic dihydric alcohol) polymers having carbonate moieties, aromatic or cycloaliphatic dicarboxylic acid moieties and carbonate moieties and having high glass transition temperatures (over 100.degree. C.) and being melt processable. At least part of the aromatic dihydric alcohol moieties have the 4-carbon of each of two phenoxies covalently bonded to the same ring carbon of a carbocyclic or heterocyclic moiety. Representative poly(ester carbonates) are formed from bisphenol-A, phenolphthalein, terephthaloyl chloride and phosgene.

Abstract: Poly(ester carbonate) polymers are prepared by reaction of bifunctional phenolates in an aqueous phase with phosgene and with the acyl halide of a bifunctional carboxylic acid halide such as terephthaloyl chloride in an organic solvent such as dichloromethane. At least a portion of the phosgene is reacted with the phenolate before or during reaction of the acid chloride with the phenolate to avoid the formation of polyester blocks which have limited solubility in the organic solvent. After reaction is complete, or at any stage wherein oligomers are formed, the aqueous phase can be cleanly removed and easily separated from the organic phase, and the organic phase readily washed free of by-products. The final polymer product is recovered from the washed organic phase and is colorless, substantially amorphous and melt processable, and has a high glass transition temperature.