Abstract: A process for the preparation of polybenzazole filaments which comprises (a) extruding a solution of polybenzazole polymer in a mineral acid through a spinneret having at least 100 holes, which are arranged to form a annular pattern around the center of the spinneret, the center and at least two radial sections of the spinneret having no holes and an average width which is at least about 3 times the minimum pitch of the holes, thereby forming filaments of the polymer solution; (b) drawing the filaments of the polymer solution through a quench chamber while providing a substantially radial gas flow therein across the spinneret from at least two different directions; and (c) washing and drying the filaments of the polymer solution under conditions sufficient to form polybenzazole filaments.

Abstract: The invention is a process for the preparation of polybenzazole staple fibers which includes extruding a solution of polybenzazole polymer to form a dope filament, cutting the dope filament to a desired length, and washing and drying the cut filament. It has been discovered that the process of the invention provides a suitable means to prepare staple fibers which does not require the cutting of washed, rigid polybenzazole filaments.

Abstract: Fibers spun from polybenzazole dopes can quickly be washed to remove polyphosphoric acid by a combination of initially washing with an acidic liquid and second washing with a hot leaching fluid at at least about 60. The process can reach acceptable residual phosphorous levels (1500-2000 ppm) in as little as about 2 or 3 minutes.

Abstract: This invention aims at improvement of heat-treatment technology for manufacture of large amounts of polybenzazole fibers. The fibers are heat treated in a device that provides for a rapid, cocurrent, countercurrent or both cocurrent and countercurrent flow of heat treatment gas.

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 polyurethane composition improved in dyeing property which comprises (A) a polyurethane and (B) a tertiary nitrogen atom-containing polymer incorporated therein in an amount sufficient to stabilize the polyurethane (A), said polymer (B) being the reaction product between (C) a tertiary nitrogen atom-containing diol and an excessive amount of (D) an organic diisocyanate, the terminal isocyanate group in said reaction product being blocked with a monoamine and/or a dialkylhydrazine.

Abstract: Stretching polyester tows at a speed greater than 150 m/min., wherein more than 85 mol percent of the recurring units are units of ethylene terephthalate, is carried out at a stretch ratio satisfying the formula-1.58log(.DELTA.n .times. 10.sup.3) + 4.18 .ltoreq. DR .ltoreq. -2.32log(.DELTA.n .times. 10.sup.3) + 5.93Wherein .DELTA. n represents the birefringence of the unstretched filaments and is a value of from 0.020 to 0.100, and DR is the stretch ratio in times.