19-07-2018 дата публикации
Номер: US20180202078A1
The present invention discloses an ultra-low shrinkage polyester industrial yarn and its preparation method. The ultra-low shrinkage polyester industrial yarn is prepared by subjecting a polyester to dissolution, washing and solid state polycondensation followed by spinning. The ultra-low shrinkage polyester industrial yarn has a dry heat shrinkage rate of 1.8±0.25% under test conditions of 177° C.×10 min×0.05 cN/dtex. The polycondensation catalyst consists of magnesium ethylene glycol and antimony ethylene glycol, has a small thermal degradation coefficient. The present invention reduces oligomers during polymerization, reduces thermal degradation during processing, and as a result the invention greatly reduces impurities and nucleating agent in the polyester, leading to an increase in the probability of homogeneous nucleation based on the reduction of heterogeneous nucleation. The dissolution and washing of polyester further decreases oligomer content, facilitating the growth of the grain size and the optimization of crystal perfection in the ultra-low shrinkage polyester industrial yarn. 1. An ultra-low shrinkage industrial yarn having a dry heat shrinkage rate of 1.8±0:25% , under the testing condition of 177° C.×10 min×0.05 cN/dtex wherein the ultra-low shrinkage industrial yarn is obtained by the following process: subjecting the polyester to dissolution , washing and solid state tackifying followed by spinning , esterification of terephthalic acid and ethylene glycol and the polycondensation catalysed by a mixture of magnesium ethylene glycol and antimony ethylene glycol followed by granulation ,wherein the carboxyl end group is less than 15 mol/t, the mass percentage of oligomer is lower than 0.5%, and weight percentage of diethylene glycol is lower than 0.5%;{'sub': 2', '2', '2, 'wherein the molecular formula of magnesium ethylene glycol is Mg(OCHCHOH);'}wherein the dissolution and washing refers to that the granulated slices are scoured and washed with ...
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