Research And Development On Low-Fine Denier Full Dull Polyamide6Filament

Low-fine denier filament product has many excellent characteristics, it is one of the important trends for polyamide6development in the future. Currently, the production of polyamide6filament mainly concentrate on conventional products in our country. Products that linear density under20D are still at the initial research stage.The paper studied two kinds of low-denier filaments15D/24F and20D/24F Starting with spinning raw materials, we chose two kinds of full dull chips that from A and B company respectively, besides the conventional performance testing, we also systemically studied the thermal and rheological properties of the two chips by thermal analysis techniques (DSC/TG) and capillary rheometer, aiming to provide a theoretical basis for seeking best melt-spinning conditions; And selected proper spinnerets based on rheological properties of the chips and the actual production situation; Finally, set the spinning process conditions according to the low-fine denier filament characteristics, chips properties as well as factory production experiences; The paper systematically studied and analyzed the draw-ratio, heat setting temperature and pump capacity influences on physical properties, thermal properties and aggregation structure of low-fine denier polyamide6fiber.This paper mainly arrived at the following conclusions:1.The thermal properties of two full dull chips showed that:A chip could crystallize more easily, and there was no obvious difference in hot weightlessness of the two chips before temperature reached280℃, it was also proved that the two chips could satisfy the normal spinning.2.Rheological properties of two full dull chips showed that:melt apparent viscosity decreased with the increase of temperature, so the melt liquidity and spinability were improved correspondingly; When extension strain rate increased, polyamide6melt property was less influenced by temperature, so melt stability got better; When in the same extension strain rate, the viscous activation energy of A chip was higher than B chip which demonstrated that the apparent viscosity of A chip were more reliant on temperature.3.Keeping the total draw ratio unchanged, increasing the drafting roller draw ratio could improve the fiber strength more effectively and the crystallization and orientation of the fiber were increased correspondingly, but little change in the crystal form which still remained the y form in fiber.4. When heat setting temperature was below180℃, fiber strength had a tendency to increase with the increase of heat setting temperature but when heat setting temperature was higher than 180℃, strength changes were not obvious. Experiments also showed that heat setting temperature had significant influence on boiling water shrinkage of the fiber, the internal structure of the fiber can be improved in a certain degree with higher heat setting temperature, but little change in the crystal form which still remained the y form in fiber.5.Under the same linear density and draw ratio conditions, fiber strength was higher if given higher pump delivery, but no influence on boiling water shrinkage. The crystallinity of fiber with different pump capacities showed that increase pump capacity can improve the crystallinity in a certain degree, but the crystal form was uninfluenced by pump delivery.