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Polypropylene industrial yarn is used as a reinforcement for a wide range of manufactured products such as conveyor belts, drive belts, V-belts, seat belts, hoses, tires and more. Polypropylene industrial yarn with high toughness, high modulus and dimensional stability is usually important. Melt-spinning polyethylene terephthalate into spun filaments, followed by stretching the spun filaments in a heated zone to a draw ratio of at least about 1.05: 1; producing a highly uniform polypropylene industrial yarn, Wherein said spun polypropylene industrial yarn has a birefringence of at least about 0.075 and a crystallinity of at least about 10%; wherein the spun-out polypropylene industrial yarn has a residence time in the heated zone of at least 0.3 seconds; and wherein in the heated zone Of the yarn is at a temperature between the glass transition temperature and the melting temperature of the polyethylene terephthalate.