| The water repellent effect of fabric is usually achieved by using additives to change the surface properties of fabric.The critical surface tension can be reduced below the surface energy of water and the fabric will obtain water repellent effect.The traditional water repellent finishing methods can be divided into three categories: film lamination.coating finish and fluorocarbon impregnation finishing.All of the above finishing methods form a film layer with water repellent function between the surface of the fabric or the yarn space on the surface of the fabric so that the fabric can obtain reliable water repellent effect,and the process is simple and effective.The cost of film lamination is high,and the quality of products is unstable due to the instability of raw material.The discharge of pollutants in the production process of coating finishing and fluorocarbon impregnation finishing will cause pollution.In use process,the water repellent functional media will cover the surface of fibers or fabrics,thus the functional media will be lost to varying degrees due to friction with the external materials.At the same time,it will cause certain pollution,too.As a result,the wearability and water repellency durability of the finished product will be reduced.Compared with woven fabric,knitted fabric has a special coil structure.Under the external tension,the shape of the needle loop and sinker loop will change,which has a good elongation.In use process,the water repellent film is easy to break,and the water repellent effect is weakened,which limits the application scope of this kind of fabric.Therefore,it is necessary to improve the traditional water repellent finishing method,so that the object of water repellent finishing is not only limited to the range of fabric,but also the fiber and yarn can be treated with water repellent finishing.Thus,a new method of water repellent function of fabric is obtained by water repellent finishing of fiber and yarn and subsequent processing.Based on the hollow structure of a hollow polyester fiber,a new water repellent modification method is proposed in this paper.The water repellent agent is applied to the cavity of polyester hollow fiber by vacuum filling method,the water repellent agent will be cross-linked with each other of the fiber or between the water repellent agent and the inner wall of the fiber in the inner cavity,so as to reduce the friction loss of the water repellent functional medium in the use of the fiber.Water repellent polyester hollow fiber,which is different from the traditional water repellent fiber,was made and tested to study the water repellency of the treated material and to explore the influence of the water repellent modification method on the dyeing performance of polyester hollow fiber.The research process consists of the following three parts:(1)Study on the water repellent modification process of polyester hollow fiber: fill the water repellent agent into the cavity of polyester hollow fiber by vacuum filling method,observe the filling effect of water repellent agent by scanning electron microscope to confirm the feasibility of vacuum filling method,and take the contact angle test result as the water repellent effect index of the sample to determine whether the water repellent modification of polyester hollow fiber by this method can achieve water repellent effect.The results show that the water repellent modification of PET hollow fiber is effective and feasible.At the same time,the effects of pre-baking temperature,baking temperature and water repellent concentration on water repellent modification of polyester hollow fiber fiber were discussed.The experimental results show that the optimum parameters of water repellent modification are,water repellent concentration:150g/L,vacuum treatment time: 50 min,pre-baking temperature: 110? and pre-baking time:3min,baking temperature: 150? and baking time:3min.(2)Based on the dyeing research of water repellent modified PET hollow fiber: taking the PET hollow fiber which has been water repellent modified as the research object,the dyeing behavior and performance change of the fiber in the subsequent dyeing process were discussed.Generally,dyeing for polyester is carried out under the condition of high temperature and high pressure.In this condition,whether PET hollow fiber can be colored normally,the size of coloring rate,and the effect of dyeing process on water repellent effect are the focus of this study.The dyeing effect and water repellent effect were tested and evaluated by comparing PET hollow fiber which has been water repellent modified before dyeing and PET hollow fiber which has been dyed before water repellent finishing.The experimental results show that the K / S value of PET hollow fiber which has been water repellent modified with 150 g / L water repellent agent before dyeing can reach 5.7,which shows that the dyeing effect is good.The average contact angle of dyed fabric is 131.5°(the droplet stayed for 5s),128.5°(the droplet stayed for 60s),which shows that the water repellent effect is good.The K / S value of PET hollow fiber which has been dyed before water repellent finishing with 50 g / L water repellent agent can reach 5.3.The average contact angle is 127.75°(the droplet stayed for 5s)and 123.35°(the droplet stayed for 60s),which shows that the dyeing effect and water repellent effect are all good.The attenuation behavior of water repellent effect was studied by water washing contrast test.After 30 times of water washing,the contact angle of the fiber decreased within 3°,which had no significant effect on the water repellent effect.The contact angle could reach 145° at most,and decreased within 5° after 30 times of soap washing,which had no significant effect on the water repellent effect.(3)The best process sequence of water repellent modification process and dyeing process of PET hollow fiber are discussed.A comparative experiment was carried out,water repellent modifing before dyeing of PET hollow fiber and the water repellent finishing of raw fiber after dyeing,to get the better process method.Through SEM,contact angle test results and K / S value,the properties of the two groups of treated PET hollow fiber were compared,and the morphological changes and performance changes of PET hollow fiber which has been water repellent modified before dyeing and PET hollow fiber were explored.The results show that there is irreversible damage on the surface of PET hollow which has been dyed before water repellent finishing.The peak value of contact angle is 145° and the average value is 131.5°(the droplet stayed for 5s).The K / S value of PET hollow fiber reached a peak value of 5.7 when it was dyed with water repellent modification at the best water repellent concentration(150g / L);the surface of PET hollow fiber with water repellent modification process set before dyeing process was almost undamaged,the peak value of contact angle was 139°,the average contact angle was 127.75°(the droplet stayed for 5s),123.35°(the droplet stayed for 60s)and the average contact angle was 127.75°(the droplet stayed for 5s),123.35°(the droplet stayed for 60s).After dyeing,the K / S value was only 5.3 when modified with the best water repellent concentration(150g / L).The results show that the water repellent effect and dyeing effect of the polyester hollow fiber which has been water repellent modified before dyeing are better than that of the PET hollow which has been dyed before water repellent finishing.Therefore,water repellent modification process is set before dyeing process of PET hollow fiber will make it obtain better water repellent effect and dyeing effect. |
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