Development And Performance Study Of Polylactic Acid/latex Yarn Interwoven Flame-retardant Elastic Band

Elastic band accessories textiles have a wide range of application prospects due to their special resilience and decorative effects in many sportswear,leisure wear,underwear,home textiles,transportation seating fasteners and daily life.At present,the domestic and foreign markets for a variety of functional elastic fastening band taking products increasing demand,but today most of the elastic band raw materials for polyester and nylon,after the waste are faced with degradation difficulties and pollution of the environment and other problems,limiting the practical application of elastic band.Polylactic acid（PLA）,a biomass material prepared by fermentation from renewable resources such as corn,cassava and sugar beet stems,can be degraded to CO₂ and water under natural conditions,which solves the shortage of petroleum resources and environmental hazards caused by traditional polymer materials.However,PLA is a flammable fiber,and a large amount of molten droplets will be generated when it is heated,which leads to great safety hazards in the use of its products,so it is important to study the flame retardant modification of PLA fiber.In this paper,we firstly prepared an environmentally friendly elastic band with PLA fiber and flame retardant latex yarn as raw materials.Secondly,we systematically studied the flame retardant finishing process of the elastic band,and finally analyzed the flame retardant performance and quality advantages and disadvantages of the elastic band after finishing by the optimal flame retardant process.The main research contents and results are as follows:（1）PLA filament of 150D/144f and No.40 flame retardant latex yarn were used as raw materials,and five kinds of woven elastic bands with weft density of 129.9,141.7,157.1,172.4 and 178.7 pcs/10cm were designed and woven on Wanlida narrow width fabric machine.The different weft densities have a great influence on the performance of the elastic bands,among which the tensile ratio and elastic recovery rate are important indexes to classify the product quality grade.The corresponding quality of the five types of elastic bands are in order:qualified,qualified,first grade,superior and superior.（2）A low-toxic and high-efficiency cyclic phosphate ester flame retardant was used to modify the flame-retardant finishing of PLA elastic bands by an impregnation-baking process.The effect of flame retardant mass concentration and impregnation process conditions on the flame retardant performance of elastic bands was firstly explored by using L₉（3³）orthogonal test,and the optimal flame retardant finishing process was further optimized by single-factor experiment to determine:flame retardant mass concentration of 250g/L,impregnation temperature of 50℃,impregnation time of 2h,baking temperature of 165℃and baking time of 30s.Under this process,the damage length of vertical burning of the elastic band is only3.9cm,and it can be self-extinguished without molten drops after leaving the fire source,which meets the flame-retardant standard of FAR25.853（a）-1995 of the United States aviation fireproof material.（3）FT-IR,SEM,EDS and TG were used to analyze the flame retardant mechanism of elastic bands,and the effect of optimal flame retardant process conditions on the quality of elastic bands was studied.The results showed that the physical adsorption process of the flame retardant finishing onto the PLA elastic band,the cross-linking phenomenon between the PLA fibers after finishing could promote the formation of a more stable and continuous carbon layer structure when the substrate is burned,and the distribution of 4.41%of P elements on the surface of the carbon layer also indicated that the flame retardant facilitated the dehydration carbonization process of the material,thus providing a good flame retardant effect.After finishing,all five kinds of elastic bands have good dimensional stability,and at the same time,the comfort and fatigue resistance are good,and the loss of strength is kept within 10%,which can meet the needs of daily use.The elastic bands with the weft density of172.4pcs/10cm are excellent before and after finishing,and priority should be given to the production of PLA woven elastic bands with this specification.