Abstract: Process for producing a flame retardant acrylic fiber by wet-spinning a halogen-containing acrylic spinning solution containing antimony oxide particles dispersed therein, wherein an acrylic fiber having a high degree of flame retardancy and improved fiber properties, such as transparency, luster and brightness of colors of dyed products, is produced in an industrially advantageous manner by regulating the water content in the hydrogel fiber obtained by hot stretching after wet-spinning within a range of 50-130% based on the fiber-forming polymer.

Abstract: Method taught for producing a high modulus yarn of filaments of a polyester resin consisting of at least 15 up to 50 mole percent of bibenzoate units and from 85 to 50 mole percent of terephthalate units, said yarn having been uniformly oriented and then heat-set while free-to-relax.

Abstract: A low shrinkage polyester fiber is produced by melt-spinning a polyester polymer under conditions of substantially simultaneous spinning, drawing, and heat treating, using carefully controlled conditions whereby the fiber has uniform properties of breaking strength in grams per denier of at least 7.0, elongation at break in percent of 18 to 30, and a residual thermal shrinkage measured in an oven at 350.degree. F. for one minute of lower than 3 percent. The low shrinkage polyester fibers are particularly useful in the preparation of reinforced elastomeric structures.

Abstract: A process for continuously heat setting a tubular film of biaxially oriented polyethylene terephthalate in a state expanded with a gaseous material and taking the heat set film up on a winder which comprises carrying out the heat setting in a heat setting chamber wherein the temperature is controlled so as to be initially in the range of about 220.degree. C.-240.degree. C. in the first zone of heat setting and thereafter declines to about 195.degree. C.-215.degree. C. in the final zone while the length of the film is increased about 2% - 7% and the diameter of the film is reduced about 5 - 15% from the corresponding dimensions of the film before heat setting, the film then being taken up by a rotary winder.

Abstract: High strength fibers and films are prepared from melt extrudable (co)polyazomethines.

Abstract: Heat-resistant aromatic polyester filaments having heretofore unknown physical properties and a combination of excellent heat resistance and mechanical strength, which (1) is composed of an aromatic polyester in which at least 90 mole % of the structural units are ethylene-2,6-naphthalate units, (2) has a melting point at a constant length (Tm;.degree.C.) of at least 287.degree. C., (3) has a density (d)(g/cm.sup.3) of at least 1.370, (4) is insoluble in a phenol/orthodichlorobenzene mixed solvent (mixing ratio = 6/4 on the weight basis) at 160.degree. C. and (5) meets the requirements expressed by the following formulaeL(Tm - 280) = 400 (I).DELTA. n(d - 1.350) = 70 .times. 10.sup.-.sup.3 (II)L = .lambda.K/(B-b)cos .theta. (III)and the process for the preparation thereof.

Abstract: A heat-sealable, heat-shrinkable, biaxially oriented polyester film is provided which is usable in making shrink packages having improved seals and improved optics by reason of having:A relative viscosity (at 1% concentration in 60/40 tetrachloroethane/phenol at 30.degree. C.) of at least 1.80;Substantially balanced latent shrinkage of from about 31% to 47% at 100.degree. C.;an average shrinkage force of less than about 1,000 psi at 100.degree. C.;a melting point of from about 215.degree. C. to 230.degree. C.;haze of less than 5%; andSuch film being essentially polyethylene terephthalate.

Abstract: A process is provided in which a continuous filament polyethylene terephthalate yarn having an HRV in the range of 24 to 28 is heated to a temperature in the range of 75.degree. to 250.degree. C. and drawn to a total denier in the range of 50 to 500 at a draw ratio in the range of 5.2:1 to 6:1, passed over a draw roll having a temperature in the range of 225.degree. to 250.degree. C., relaxed at a tension in the range of 0.09 to 0.15 gram per denier and wound up at a minimum speed of 2,000 yards per minute (1829 meters/minute). The yarns prepared by this process have a tenacity in the range of 7.5 to 9 grams per denier, a load-bearing capacity in the range of 3 to 5 grams per denier at 7% elongation, a maximum dry heat shrinkage of 4% at 177.degree. C. and an elongation at break in the range of 12 to 20%.

Abstract: The invention is related to a process for the production of improved, low shrinkage, highly oriented polyester threads which comprises melt spinning a polyester thread, stretching said thread in hot water and shrinking said thread from 3 to 22 % in hot air at temperatures of from 5.degree. to 40.degree. C below the melting point of the polyester over a period of from 3 to 30 seconds. The improved service properties of monofilaments produced in this way are reflected in an increase in the ultimate tensile strength coupled with an increase in elongation, in a shrinkage of less than 1% on boiling, in a heat-included shrinkage of at most 10% at a temperature of 195.degree. C (exposed for 30 minutes in air) and in a very high 2nd moment.

Abstract: A process for the relaxation of fabric containing polyurethane yarn includes the steps of forwarding the fabric continuously through a treatment region in which it is subjected to the action of a swelling agent, for example a chlorinated hydrocarbon, which swells the polyurethane yarn, the treatment being such that the modulus of the yarn is reduced by no more than 12.5 percent, and drying the yarn after it has left the treatment region.