Structure And Mechanical Property Analysis Of A Combination Material Of PE/PP Spunbond Nonwoven And TPU Elastic Film

Nowadays, development of nonwoven technique towards intermixing and combination becomes a very obvious trend in worldwide scope. As combination of several various technics can compensate the defect of single technics, man invents many sorts of modern and various nonwoven products. Among them the elastic combination material is widely needed but with high demands in its producing technics.In recent years, nonwoven made by bicomponent spunbond method attracts more and more attention with its high strength, good tensile property and soft handle. Combination of different raw material and different combination pattern can change the variety of nonwoven. So various products with different respective speciality and function appear and this greatly extends the application and the market of nonwoven.TPU elastic film not only has good tensile property and comfortable handle, but also possesses other properties such as high break strength, good wearable and dank property, high physical and mechanical performance and good machining performance. So it is a very widely used film product.This project chooses PE/PP bicomponent spunbond nonwoven and TPU as raw material and puts their advantages together. In addition, it also takes elastic combination material which is described in American patent 4525407 as structure prototype to make a 3D elastic combination material. In domestic there is nearly no research on such a type of elastic combination material in theory aspect and also no related producing equipment, experience parameter and so on. Whereas this type of elastic combination material has broad application market and development future, this project's aim is exploringly to research some problems about the choosing of raw material, combination technics and other aspects of this elastic combination material and to exploit the first step for this type of combination material in domestic market.First of all, this dissertation introduces and analyzes the raw material of this type of elastic combination material, which includes PE/PP bicomponent spunbond nonwoven, TPU and combinative medium i.e. hot melt adhesive. Then it explains the manufacturing method of the elastic combination material in the experiment.Afterwards this dissertation establishes the structure model of this material. And through the analysis of this model it concludes that when the width of adhesive, the width of nonwoven between two adjacent points and Draw Ratio of the elastic film are constant, accompanying the decrease of the recovery of elastic film the width of elastic film between two adjacent points increases, meanwhile, the hunching height and elongation ratio of elastic combination material decrease.The structural specialty gives material a special mechanical performance. This type of elastic combination material experiences a more complicated stress-strain course in low distortion area which is different from the tensile strain course of common textile material. Therefore, this dissertation establishes the viscoelastic mechanics model for this course and imports the Boltzmann theory for setting up the step function to token this course. Through function fitting and analysis a conclusion can be gotten, namely, the elastic performance of elastic combination material is supplied by elastic film, but the structure of combination material limits the elasticity of the elastic film and make it work only in low distortion condition; nonwaven layer has the crucial effect on the breaking strength and the ultimate elongation of the elastic combination material. Additionally, through the fitting value of parameter it could be got that the fitting value of parameter E₁ could reflect the elastic elongation property of the elastic combination material in the initial drawing step and the fitting value of parameterηcould reflect the transmogrification resistance property of the elastic combination material.Based on the analysis of this type of elastic combination material by means of the mechanics model and structure model, this dissertation researches this material in the aspects of choosing raw material and setting technics parameters, namely lets the theory research in combined with practical application. Except analyzes solo factors, this dissertation also uses the way of orthogonal analysis to get the best compound value of temperature, pressure and time in this test and which is 90℃for temperature, 3.6MPa for pressure and 15s for time. Thereby this dissertation offers useful suggestion to the producing technics of this type of elastic combination material and further systemizes and standardizes its producing process.