聚酯熔体质量对中空涤纶短纤维闭合成孔能力的影响

Effect of polyester melt quality on pore-forming property of hollow polyester staple fiber

采用熔体直纺技术、以C型喷丝板生产中空涤纶短纤维,探讨了聚酯熔体质量对纤维闭合成孔能力的影响。结果表明:在正常生产工艺条件下,熔体的出口膨胀效应是影响纤维闭合成孔能力的主要因素,熔体质量影响熔体的表观黏度继而影响熔体的出口膨胀效应;聚酯熔体常规指标接近时,其熔融结晶温度(Tmc)和相对分子质量分布宽度指数(PDI)对闭合成孔能力影响较大,对于同一条生产线,熔体Tmc突然降低,易导致中空纤维破裂丝增多,对于不同生产线,Tmc高的熔体对生产负荷、工艺波动的适应性较好,产生破裂丝的概率较低;在相对分子质量相近时,熔体表观黏度随着PDI增大而急剧下降,出口膨胀效应减弱,破裂丝增多;适当提高熔体特性黏数和Tmc,降低PDI,有利于提高纤维闭合成孔能力、减少破裂丝的产生。

A hollow polyester staple fiber was prepared by using C-shaped spinneret via direct melt spinning process.The effect of polyester melt quality on the pore-forming property of the fiber was discussed.The results showed that the die swelling of melt at the exit was the primary factor affecting the pore-forming property of the fiber under the normal production conditions,and the melt quality affected the apparent viscosity of the melt and then the die swelling of the melt at the exit;the melt crystallization temperature(T mc)and the relative molecular mass distribution width index(PDI)had great effects on the pore-forming property of the fiber when the general physical indices of the polyester melts were close to each other;the sudden drop of T mc could easily increase the breaks of hollow fiber for the same spinning line when the melt with high T mc was more adaptable to the production load and the process fluctuation and generated less breaks for different spinning lines;the apparent viscosity of the melt was sharply decreased,the die swelling of the melt at the exit was weakened and the breaks were increased with the increase of PDI when the relative molecular mass was close;and the pore-forming property of the fiber could be improved and the breaks could be depressed by reasonably increasing the intrinsic viscosity and T mc and decreasing PDI of the melt.