Study On The Properties And Spinning Feasibility Of Dope-Dyed Acrylic Fiber

Since fifties of last century,acrylic fiber has been widely used because of its excellent properties,such as its bulkiness,warmth retention,soft handle,and easy dyeing,etc.However, acrylic fiber on the market currently is dyed by organic dyes in the form of fibers or fabrics,so the requirement of dyeing process is very strict,and dye consumption is very high with terrible pollution.But the production of dope-dyed acrylic fiber eliminates the later dyeing process on account that the paint is directly joined in spinning solution to achieve fibers coloring,thereby significantly reducing the pollution to the environment.While dope-dyed acrylic fiber can be widely applied in high-grade sunshade and shade cloth with good resistance to light degradation performance,and economic benefit and social benefit are extremely significant.According to the statistics,non-ferrous acrylic has accounted for more than 20 percent of the world total acrylic.In recent years,due to the massively application of acrylic in outdoor market,dope-dyed acrylic fiber has further development.But so far only several companies in Britain and the United States,Germany,Italy,Japan,etc preliminary master the technology,and the acrylic department of Shanghai petrochemical Co.,ltd.has now mass industrial and batch production ability of chromatographic dope-dyed acrylic fibers.At present the basic research about dope-dyed acrylic fibers is rarely seen,and the domestic research stays in the fiber technology and product development,system research according to the dope-dyed acrylic fibers and later processing technology should be conducted urgently.In the thesis the relationship between the processing parameters and strength and extension properties of dope-dyed acrylic yarn and fiber structure and properties are investigated in order to give a reference to the production or the theoretical research.Firstly,on the basis of successful development of the dope-dyed acrylic fiber,by the means of X-ray diffraction analysis,and scanning electron microscope,the crystalline structure, orientation structure and morphology structure of the dope-dyed acrylic fiber were investigated. The results indicated that the crystalline structure,orientation and morphological structure were influenced by the pigment.Meanwhile,the physical,mechanical properties of the dope-dyed acrylic fiber were improved obviously,and heat-resistance was relatively good,but hygroscopic property changed little,its overall performances are better than conventional acrylics'.Secondly,based on the specialty of better loftiness,longer fiber length,better regularity etc suitable processing circulation were chosen and optimized to spin medium dope-dyed acrylic fiber pure yarn.The performances of the formed yarn are tested.The research results give guidance for the spinning practice of dope-dyed acrylic fiber.The results indicated:In spinning process,the principle of opening and cleaning process are the reducing of fiber damage,extending feeding plate & processing of lighter weight per unit length,heavy pressure,big gauge was adopted in carding process suitably,measures of heavy pressure,lighter weight,medium speed, medium gauge and so on was adopted in drawing process,principle of big gauge,heavy pressure, proper tension,proper twist factor was adopted in roving process and spinning proces. Thirdly,the technological factors affecting the strength of yarn are analyzed in correct order.Then the general rotatory composed design method is applied,selecting draft multiple of back zone and twist factor in spinning process as research objects.Finally use the goal programming method to solve the optimal solution,and select breaking strength,strength evenness and yarn evenness as objective function,and others are been as constraint conditions to get the optimal process parameters,that is to say,the draft multiple of back zone is 1.3657,and twist factor is 379.7449.Followed by,the optimum process parameters were tested.The results show that the optimized parameters of yarn strength is obviously better than the results without optimization,and the composite indicator of the yarn are more excellent,and achieve the purpose of the development of high strength dope-dyed acrylic yarn to meet the end use requirements.At last,the relationship between the later spinning processing parameters and strength and extension properties of dope-dyed acrylic yarn is predicted using the back-propagation network(BP) and adaptive neural-network-based fuzzy inference system(ANFIS).Compared with linear regression method,the prediction results agree well with the experimental data,and the prediction of the ANNs is close to the real data,especially ANFIS.It's proved the selecting methods are efficient and right,as well as the ANNs can be used to predict the strength and extension properties of rotor spun yarn.