Analysis Of Selective Adhesion Properties Of Microstickies In Papermaking Whitewater Of Recycled Paper

The stickies obstacles in recycled paper is still a technical problem hindering the development of recycled paper pulping.Stickies will adhere to various surfaces in the process of papermaking,including synthetic fiber surface such as molded net and blanket,as well as metal surface such as dryer,which directly affect the quality of paper products and the performance of paper machine.In addition,due to the performance requirements of paper products,the papermaking system will use a variety of papermaking chemicals containing binders,resulting stickies substance material is easy to adhere to the fibers.Meanwhile,the more complex sources and properties of stickies also bring a series of difficulties to its research.Therefore,studying stickies from different sources separately and systematically and exploring their adhesion rules to different surfaces will help to analyze the stickies characteristics and find effective measures to solve stickies obstacles.Two types of microstickies,from papermaking chemicals and pressure sensitive adhesives,were selected as the research objects.On the basis of characterization of their,the selective adhesion characteristics of the two kinds of microstickies to the surface of common fiber materials were studied.The results are as follows:The main component of pressure sensitive adhesive 7005(manufacturer number)was ethylene-vinyl Acetate copolymer,its glass transition temperature was-38.6 ℃.Pressure sensitive adhesive 7055(manufacturer number)were polyacrylic acid,its glass transition temperature was-30.9 ℃.As the common papermaking chemicals AKD and XSBRL,These ingredients were sticky under the common conditions of papermaking system.For the above two types of stickies,the adhesion results of cotton fiber surface,polyester fiber surface and modified cotton fiber surface were as follows:Microstickies originated from papermaking chemicals(AKD and XSBRL)adhered to the surface of cotton fiber,and the adhesion efficiency was obvious and can reach more than 30%.The adhesion of microstickies originated from pressure sensitive adhesive(7005 and 7055)to its surface was not consistent.The adhesion efficiency of cotton fiber surface to the microstickies in 7005 suspension was low.However,the adhesion efficiency of cotton fiber surface to microstickies in 7055 suspension can reach 40%,and the adhesion effect was obvious.For the surface of polyester fiber,the adhesion of microstickies originated from papermaking chemicals(AKD and XSBRL)and pressure sensitive adhesive 7005 on the surfaces were poor.But the adhesion effect of 7055 microstickies was just the opposite,the surface adhesion efficiency can reach 26%.For the surface of modified cotton fiber,the adhesion effect of microstickies originated from papermaking chemicals(AKD and XSBRL)and the pressure sensitive adhesive 7005 on the surface was not obvious,and their adhesion effects were different.But the adhesion effect of the modified cotton fiber surface to the 7055 microstickies was the opposite,the adhesion efficiency can reach more than 50%,and the adhesion effect was obvious.In addition,the results of the microstickies in whitewater come from the factory showed that the adhesion of the microstickies on the surface of cotton fiber,polyester fiber and modified cotton fiber had obvious selectivity.The aadhesion effect on the surface of cotton fiber and modified cotton fiber was better,the adhesive efficiency was 19.7% and 15.2% respectively.But the adhesion effect on the surface of polyester fiber was worse.When three kinds of fiber surfaces are bonded together under the same conditions,the adhesion range of the microstickies in whitewater was also increased.That is,the surface of cotton fiber + modified fiber,cotton fiber + polyester fiber,and modified fiber + polyester fiber,their adhesion efficiency was higher than the surface with lower adhesion efficiency in the bonding surface.To sum up,the source and properties of stickies determined their adhesion selectivity on different surfaces,and the mixed stickies still had adhesion selectivity on different surfaces,and with the increase of adhesion surface types,the adhesion range of mixed stickies was also increased.