Spinning Technology Of Durable Water-Repellent PP/PE Heat-Adhesive Core-Sheath Composite Fiber And Study On Its Behavior

By extruding two polymer materials polypropylene (PP) and polyethylene(PE) from a double screw extruder, we can get their respective melt. Then the two melt which have certain proportion and viscosity are respectively put into a core-sheath composite spinning pack and PP/PE low melting point heat-adhesive core-sheath composite fiber was got by extruding the two melt from the same die-spinning nozzle. This kind of composite fiber will get a water-repellent property by using waterproof finishing oil during the finishing process. Nonwoven fabrics got by the fiber especially have a very soft hand touch and good breathable water-repellent property, so they are widely used in hygienic textile materials such as napkin for babies, sanitary napkin for women.This paper discussed the spinning technology of the core- sheath composite fiber briefly. The thesis was studied on three aspects emphasis: Using polymer theory to have described the molecule structure of PE which make it have low melting point, high cohesiveness and good spinnability; Using oil theory to Make water-repellent finishing oil and give the composite fiber water-proof, good breathable water-repellent properties by proper oil-giving process; Having introduced the spinning technique of PP/PE heat-adhesive core-sheath composite fiber and analyzed its properties by methods of data processing, fit polynomial and observing through microscope, etc.Main conclusions can be drawn as follows from the study. (1) In this paper, some brands of PE chips were analyzed and comparedfor their molecular weight, heat behavior, melt rheology and spinnabilities. The result indicated that PE with melt index of 15~25, MW of 7~12 104 and PP with melt index of 20~30, MW of 14~16X 104 could be used for the composite spinning and the need of heat-cohesiveness.(2) By choosing the water-proof finishing oil and designing the coordination of oils for the spinning properly, the PP/PE low melting point heat-adhesive core-sheath composite fiber could be endured perfectly durable Water-repellent property.(3) By means of sonic velocity method and density method and so on, the paper indicated that the moleculars of the composite fiber would have higher orientation as the drawing ratio increased, and at the same time, the orientation induced the crystallization of moleculars. The density, the breaking strength and the shrinkage in boiling water of the fiber increased and the breaking extension decreased as the drawing ratio was increasing.(4) Nonwoven fabrics got by the fiber especially have a very soft hand touch and good breathable water-repellent properties besides its good elastic performance and non-toxicity, so they are widely used in hygienic textile materials such as napkin for babies, sanitary napkin for women.