Research On The Modification Of Kaolin And Its Application In Polyamide Wet Coating

Polyamide wet coating use methanol and anhydrous calcium chloride to form soluble system to dissolve waste polyamide,and add a certain proportion of fillers into the polyamide coating slurry,which is used to coating on the polyamide fabric or blended fabric containing polyamide fiber,then immerse in the coagulation bath to generate a high molecular film on the fabric surface,finally washing and drying the fabric to get polyamide coating trademark fabric which meets various printing standards.As an important filling agent for the processing of polyamide wet coating,kaolin's adding not only reduces the processing cost,but also helps regulate the viscosity of the coating slurry,better adapts to the production process,and also improves the whiteness and the printing performance of the products.However,in existing trademark fabric,the polyamide coating products using kaolin as filling agent still have many problems,such as the fabric's resistance to bond and ink-absorption are poor,the high pH,large edge wear when cutting products,etc.To solve these problems,this paper mainly studied the effect of kaolin on the properties of polyamide coating products,discussed the various factors on ink-absorption of polyamide coating products,and optimized the coating formula.This paper also studied the citric acid modified process and the coupling agent modified process,discussed the modification mechanism,investigated the effect of different modified methods on ink-absorption,pH value and fabric style of the polyamide coating products,and developed the filler modified process and its coating applied technology which were more suitable for enterprise manufacture.By studying the effect of kaolin on the properties of polyamide coating products,explored the effect of various factors on the ink-absorption of polyamide coating products,and optimized the polyamide wet coating formula.The result showed that the properties of polyamide coating products meet the actual production requirements of enterprise basically when the mesh number of kaolin was 600-3000,its dosage was20-25g and the waste polyamide dosage was 15-20g.The influence order of various factors on the ink-absorption of polyamide coating products was waste polyamide dosage,kaolin dosage and mesh number of kaolin.The coating formula was that absolute methanol 100g,anhydrous calcium chloride 35g,waste polyamide 20g,3000mesh kaolin 22g,and polyether 2.3g.Citric acid was used to modified kaolin,compared the applied effect of citric acid modified kaolin and other fillers in polyamide wet coating.The results showed that kaolin with the best adsorptive performance of rhodamine B and obvious modified effect when the citric acid concentration was 2.0mol/L,the treated time was24h and the treated temperature was 40?.During the reaction of citric acid and kaolin,H⁺acted on the surface and interlayer of kaolin,and reacts with Al³⁺and Si⁴⁺in kaolin,resulting in change of kaolin stratified structure.After using the modified kaolin in polyamide wet coating,the ink-absorption of polyamide coating products was improved,and its p H value was better to meet products environmental needs.Different coupling agent were used to modified kaolin,compared the applied effect of coupling agent modified kaolin and other fillers in polyamide wet coating.By testing the active index and the settling volume of kaolin,found that using glycidoxypropyltrimethoxysilane?KH-570?to modified kaolin could get better modified effect.KH-570 and kaolin were combined by the reaction of-OH to generate Si-O-Si.The influence order of various factors on the modified effect was the dosage of coupling agent,the treated time and the treated temperature.Kaolin had better modified effect when the dosage of coupling agent was 16%?quality of kaolin?,the treated time was 5h and the treated temperature was 65?.After using the modified kaolin in polyamide wet coating,the ink-absorption of polyamide coating products was improved,and its pH value was decreased.By comparing the effect of different kaolin on the ink-absorption and pH value of polyamide coating products,found that using citric acid or coupling agent to modified kaolin both could improve the ink-absorption of polyamide coating products,decreased its pH value.The study selected the fillers modified process which was more suitable for polyamide wet coating was kaolin modified by citric acid,its ink-absorption of coating products were better,and its pH value decreased from 7.23to 6.32.The citric acid modified process:the citric acid concentration was 2.0mol/L,the modified time was 24h.The coating formula was that absolute methanol 100g,anhydrous calcium chloride 35g,waste polyamide 20g,citric acid modified kaolin22g,and polyether 2.3g.Considered the cost of modification,the citric acid modified process was also more suitable for enterprise manufacture.This paper used citric acid and coupling agent to modified kaolin respectively on the foundation of the optimized polyamide wet coating formula,improved the ink-absorption of polyamide coating products,decreased its the pH value,selected the more suitable modified process of fillers and coating process for enterprise manufacture,and expanded the application prospect of polyamide wet coating trademark fabric.