Studies On The Processing And Property Of The PE/PET Sheath-core Structure Spunbond Nonwovens

This paper mainly studies the influence of the production processing and the processing parameters of PE/PET bi-component spunbond nonwovens based on the positive pressure air drawing technology of the narrow slot type on the properties of the PE/PP bi-component spunbond nonwovens.The bi-component spunbond processing (the bi-component spunmelt) is as follows: two different types of polymers are conveyed through two separate sets of raw material exporting device to two extruders to be heated and melted. The polymers enter into die through two separate sets of melt filter, melt transportation pipe and the metering pump, and then reach the spinpack after the even distribution of the die. The two types of the melt combined in structure at the outlet of the spinpack, forming the bi-component melt streamlet. The melt streamlet away from the spinning board is cooled in the air, and just at the same time it is stretched with certain speed to be finer and longer, forming the fiber web through the function of air current or mechanic device, and then finally it is concreted to form the bi-component spunbond nonwovens.High-speed air stretching is adopted in the melt spinning process, the medium is high-speed air. The wide-range integral slit positive air stretching process is used, its principle: the filaments are stretched by compressed air with small quantity and easy to diffuse. The filaments have not seized directly by stretching air, they are drawn adhesive frictional force produced by high pressure air to filaments and push force occurred by fluctuation and swing of filaments under stretching equipment, the two forces together are to make the filaments stretched.During the processing of PE/PET bi-component spunbond nonwoven, the process parameter: drying temperature,revolution of metering pump,spinning temperature,quench air temperature and speed,the pressure of stretching air,the forming table speed,the thermal calendar pressure and temperature and so on. All the parameter affected PE/PET spunbonded nonwoven performances including: the fineness,crystallization and tensile strength of filament; tensile strength and elongation MD and CD,thickness,web uniformity of the nonwovens. In addition, the paper makes a specific study on the following subjects: the relationship between the spinning speed and fiber crystallization,the affect of the pressure of the stretching air towards the fiber fineness and so on. The study shows the basic causes of the forming of such relationship and will have the direct guiding function to the practical production.