Abstract: A method of preparing a polyamide acid type intermediate is provided, by using a purified inert solvent and monomer compounds, or diamine and/or diaminoamide compounds and a tetracarboxylic acid dianhydride, whose ionic impurities and free acid contents were reduced by recrystallization purification. The polyamide acid type intermediate may improve electrical properties and heat resistance of semiconductors when it is applied to, for instance, a surface-protecting film of semiconductors or an interlayer-insulating film of semiconductors having a multiple layer wiring structure.

Abstract: Poly(ester/carbonates) are produced by adding phosgene to a reaction mixture of bisphenol A and terephthalic acid as ester-forming reactants, at mole ratios in the range between 2.0:0.8 and 2.0:1.3, in which the reaction medium consists essentially of pyridine, the concentration of bisphenol A plus terephthalic acid is in the range between 5 and 50 grams per 100 ml of pyridine; and the phosgene is added under agitation at a rate of at least 0.07 gm-mmole/liter.sec. The process is carried out at temperature in the range between 50.degree. C. and 115.degree. C. and not below the temperature given by the Arrhenius equation:1nU=10-12/0.001987 Twhere U is phosgene feed rate in gram-moles/liter.second and T is absolute temperature of the reaction mixture (degrees Kelvin). Preferred phosgene feed rates are at least 0.13 gram-millimoles/liter.second; and preferred temperatures of the reaction mixture are between 60.degree. C. and 80.degree. C.

Abstract: Novel copolyesters are prepared by the interfacial condensation of bifunctional acid halides or anhydrides with bisphenols dissolved in mixtures of alkaline materials and liquid polyhydroxy hydrocarbons, ethers or amines. The copolyesters form useful fibers and plastic materials.

Abstract: The present invention relates to novel, substantially insoluble and infusible plastics which are cross-linked by way of triazine rings and, optionally, by way of tri-substituted bis-oxymethylene urea groups or urethane groups.

Abstract: A process for poly(ester-carbonates) from dihydric phenols, especially bisphenol A; aromatic or cycloaliphatic dicarboxylic acids, especially terephthalic acid; and phosgene as carbonate precursor wherein a reaction of the acid and phosgene is carried out in a first stage forming dicarboxylic acid chloride; and then phosgene and bisphenol A are added in separate streams, simultaneously during most of the second or condensation stage. Thereby only one kettle is required for carrying out the complete polymer production.

Abstract: A composition is described, useful as a thermoformable polymer, for producing shaped articles having high yield and impact strengths, good heat resistance, and good solvent resistance. The composition, which is cured, contains a crosslinked polycyanurate network polymer in which a high molecular weight thermoplastic polymer, such as a polyestercarbonate, is finely dispersed. The composition possesses a Vicat softening temperature (ASTM 1525) of at least about 10.degree. C. above that of said thermoplastic polymer alone, and an elongation-at-break value (ASTM D-638, at room temperature) at least twice that of said crosslinked polymer alone. Due to the high yield strength, lighter structural articles and components can be fabricated from the composition possessing high structural strength.

Abstract: Copolymers consisting of bisphenol-A ("BPA"), terephthalate ("TP"), and carbonate moieties in mol ratio from 2:0.8:1.2 to 2:1.3:0.7, which are melt processable in the sense of (a) showing no more than 10% change in viscosity number upon compression molding for 10 minutes at 320.degree. C. to form a plaque, (b) developing, in 2% (gm./ml.) DCM solution, a "yellowness index" of no more than 10 as observed by ASTM Test No. D-1925, using a 2 cm. path length; which copolymers approximate in properties the alternating copolymer consisting of the above moieties, as indicated by their having viscosity numbers ("I.V.") in the range between 0.6 and 1.5 dl./gm. and T.sub.G of 170.degree. to 194.degree. C., with T.sub.G vs. I.V. relationship conforming to the formula, T.sub.G =192-(11.5/I.V.)+9 and with difference of (T.sub.G -HDT) of not over 15.degree. C.; having Izod impact resistance (ft.-lb. per inch of notch) at 25.degree. C. of at least 5; and being essentially free of pyridine and of anhydride linkages.