Abstract: The present invention concerns a reactive carrier that forms no by-products during melt injection of polymer into articles such as sheets, films, fibers and containers. The reactive carrier is used to mix additives into the polymer resin. More particularly, the invention relates to the use of one or more cyclic anhydrides or substituted cyclic anhydrides as the reactive carrier. The polymer can be polyester or polyamide. Suitable cyclic anhydrides are those with a melt point of less than the polyester or polyamide, preferably less than about 160° C., and more preferably less than about 125° C. Most preferable are cyclic anhydrides with a melt point less than about 100° C. and especially suitable are those that are liquid at room temperature (25° C.).

Abstract: Polyethylene terephthalate yarn is prepared by spinning under high stress conditions in the transition region between oriented-amorphous and oriented-crystalline undrawn yarns by selection of process parameters to form an undrawn yarn that is a crystalline, partially oriented yarn with a crystallinity of 3 to 15 percent and a melting point elevation of 2.degree. to 10.degree. C. The spun yarn is then hot drawn to a total draw ratio between 1.5/1 and 2.5/1 with the resulting properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E.sub.4.5 +FS<13.5 percent, (C) a tenacity of at least 7 grams per denier, (D) a melting point elevation of 9.degree. to 14.degree. C., and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord provides high tenacity in combination with improved dimensional stability.

Abstract: Polyethylene terephthalate yarn is prepared by spinning under high stress conditions in the transition region between oriented-amorphous and oriented-crystalline undrawn yarns by selection of process parameters to form an undrawn yarn that is a crystalline, partially oriented yarn with a crystallinity of 3 to 15 percent and a melting point elevation of 2.degree. to 10.degree. C. The spun yarn is then hot drawn to a total draw ratio between 1.5/1 and 2.5/1 with the resulting properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E.sub.4.5 +FS<13.5 percent, (C) a tenacity of at least 7 grams per denier, (D) a melting point elevation of 9.degree. to 14.degree. C., and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord provides high tenacity in combination with improved dimensional stability.

Abstract: Polyethylene terephthalate yarn is prepared by spinning under high stress conditions in the transition region between oriented-amorphous and oriented-crystalline undrawn yarns by selection of process parameters to form an undrawn yarn that is a crystalline, partially oriented yarn with a crystallinity of 3 to 15 percent and a melting point elevation of 2.degree. to 10.degree. C. The spun yarn is then hot drawn to a total draw ratio between 1.5/1 and 2.5/1 with the resulting properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E.sub.4.5 +FS<13.5 percent, (C) a tenacity of at least 7 grams per denier, (D) a melting point elevation of 9.degree. to 14.degree. C., and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord provides high tenacity in combination with improved dimensional stability.

Abstract: Polyethylene terephthalate yarn is prepared by spinning under very high-stress conditions wherein oriented-crystalline undrawn yarns are obtained. Selection of process parameters yields a partially oriented semicrystalline undrawn yarn with a crystallinity of 16 to 24 percent and a melting point elevation of 14.degree. to 22.degree. C. which is drawn to produce the resulting unique combination of properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E.sub.4.5 +FS<11.5 percent, (C) a tenacity of at least 5 grams per denier, (D) a melting point elevation of 14.degree. to 22.degree. C., preferably 17.degree. to 20.degree. C., and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord unexpectedly provides high ultimate elongation and high toughness in combination with improved dimensional stability.

Abstract: Polyethylene terephthalate yarn is prepared by spinning under very high-stress conditions wherein oriented-crystalline undrawn yarns are obtained. Selection of process parameters yields a partially oriented semicrystalline undrawn yarn with a crystallinity of 16 to 24 percent and a melting point elevation of 14.degree. to 22.degree. C. which is drawn to produce the resulting unique combination of properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E.sub.4.5 +FS<11.5 percent, (C) a tenacity of at least 5 grams per denier, (D) a melting point elevation of 14.degree. to 22.degree. C., preferably 17.degree. to 20.degree. C., and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord unexpectedly provides high ultimate elongation and high toughness in combination with improved dimensional stability.