Abstract: A thermosetting polyurethane-urea elastic yarn having a thermosetting ratio of 45-65%, which is obtained by reacting a polyglycol which has a number average molecular weight of 600-6,000 and which has hydroxy at both terminals, with a molar excess of a diisocyanate compound to give an isocyanate-terminated polymeric intermediate, reacting the isocyanate-terminated polymeric intermediate with a diamine compound to give a segmented polyurethane-urea elastomer, and subjecting the obtained elastomer to a spinning step. The thermosetting polyurethane-urea elastic yarn of the present invention has superior mechanical properties and high thermosetting ratios. When applied to knit fabric, particularly to thin knit fabric for panty hose, superior appearance of the knit fabric can be achieved.

Abstract: A process for the production of polyester polyurethane elastomeric fibers having improved humid aging resistance which comprises the steps of reacting a polyester diol with an excess molar amount of an organic diisocyanate to prepare a urethane prepolymer having terminal isocyanate group at both ends thereof; extending the chain of the prepolymer with a bifunctional active hydrogen compound and 0.5 to 10.0 mole % of a diaminosilyl compound based on the total amount of the bifunctional active hydrogen compound during or after preparation of the prepolymer to obtain a polyurethane; spinning the polyurethane into fiber; and crosslinking the polyurethane during or after spinning.

Abstract: A polymeric antioxidant which comprises a monomeric unit having a formula (I): ##STR1## wherein R.sub.1 is methyl or ethyl; and a monomeric unit having a formula (II): ##STR2## which imparts an excellent resistance against heat- or light-aging to a synthetic fiber and a resin.

Abstract: A tertiary nitrogen atom-containing urethane polymer which comprises units of the following formulas (I) and (II) as the essential components and units of the following formulas (III), (IV) and (V) as the optional components, the content of the unit of the formula (I) being not less than 10 milliequivalents in terms of the tertiary nitrogen atom per kilogram of the urethane polymer, and has a molecular weight of not less than 500: ##STR1## wherein R.sub.1 and R.sub.2 are each a C.sub.1 -C.sub.4 alkyl group and, when taken together with the adjacent nitrogen atom to which they are attached, represent a nitrogen-containing heterocyclic group, R.sub.3 is a C.sub.1 -C.sub.4 alkyl group, R.sub.4 is an optionally branched C.sub.1 -C.sub.8 alkylene group, m is a positive integer and n is zero or a positive integer but m+n is a number which can provide the unit of the formula (I) with a molecular weight of 131 to 6998 and the bondings in the unit of the formula (I) may be in random and/or block, R.sub.

Abstract: An aromatic polyamide comprising (1) a unit of the formula: ##STR1## and (2) a unit of the formula: ##STR2## and being excellent in strength, rigidity and heat resistance and improved in light resistance, flexibility and wear resistance, which can be produced by polycondensation of a diamine component comprising N,N'-bis(p-aminobenzoyl)-ethylenediamine and p-phenylenediamine, the content of the N,N'-bis (p-aminobenzoyl)ethylenediamine being from about 0.6 to 50 mol %, with a dicarboxylic acid component comprising terephthalic acid or its reactive derivative in a substantially equimolar amount to the diamine component in an amide polar solvent.

Abstract: A process for producing novel aromatic polyamides having excellent heat resistance, toughness and chemical resistance and further having improved solubility, molding properties and light resistance, which comprises polycondensing a mixed diamine consisting of piperazine and p-phenylenediamine with a substantially equimolar amount of terephthaloyl dihalide in at least one amide type polar solvent (e.g. hexamethylphosphoramide, N-methyl-2-pyrrolidone, alone or a mixture thereof), wherein said piperazine is contained in a ratio of 10 to 35 % by mol on the basis of the whole mixed diamine component, and fibers produced from the aromatic polyamides having high tenacity, flexing characteristics and wear resistance and further having improved elongation ratio, knot tensile strength, fatigue resistance and fibrillation resistance.