The Development Of Nylon And Polypropylene Interwoven Velcro And Research On Its Mechanical Property

This paper focuses on the research of nylon and polypropylene interwoven Velcro and its property, and discusses their mechanics model and anti-acid dipping finishing process.Six different structures of nylon and polypropylene interwoven Velcro has been researched in this text.Through testing and analysis, some conclusions can be obtained that the better structure of the nylon and polypropylene interwoven Velcro is that zonal hook density: 1 hook: 5 warp,warp hook density:1 hook: 3 weft, which reached GB enhanced strength standard.In the weaving process,the preferred surface heating and preset temperature of the hook fastener is about 78 ℃,and control the weaving speed at about 765 r / min. In the coating process,the preferred coating formulated scheme of nylon and polypropylene interwoven Velcro: Polyurethane 100%,2-Butanone 100%, Hardener 25%; the preferred heating and drying temperature nylon and polypropylene interwoven Velcro is 105 ℃, and drying time is 8 minutes.Based on torsion spring, a physical model of single-hook strength for hook and loop fastener was established,and physical model of strength for whole hook and loop fastener was deduced.By amending parameters of the physical model, the simpler strength formulas of hook and loop fastener was obtained, and the error percentage of theory strength to practical strength was less than 4%, which could be used to calculate the strength of hook and loop fasteners within the valid range.By researching the acid and alkali resistance property of nylon and polypropylene interwoven Velcro, some conclusions can be obtained that in the same concentration of acid solution after dipping the same time, the extent of strength losses of interwoven Velcro was less than normal nylon Velcro;and nylon and polypropylene interwoven Velcro had a excellent alkali resistance property.Through the study on Velcro’s basic anti-acid optimization technology,it could be found that when the concentration of finishing agent was 45g/L,finishing time 0.5h and samples were baked under 160℃ within 80 s,the best result of Velcro’s anti-acidic property could be achieved.Andwhen compared to the regular Velcro,the peel and shear strength of Velcro improved significantly after anti-acid finishing,and the strength of the non-finishing interwoven Velcro and anti-acid finishing nylon Velcro were close to each other.With the increase of diffusion time, the acid diffusion rate of nylon Velcro is obviously faster than nylon and polypropylene Velcro,and the acid diffusion area of nylon and polypropylene interwoven after anti-acid finishing almost unchanged.At the different penetrating times,the nylon Velcro’s penetration grades was higher than the nylon and polypropylene interwoven Velcro.