Optimization Of Extrusion And Casting Film Technology Of Polyvinyl Alcohol Sol

With gradually increasing in environmental awareness, people are aware of ordinary plastic packing products always waste oil resource and pollute the environment, so biodegradable Polyvinyl alcohol(PVA) film as a environmental packing product will solve these two problems. But PVA film not yet widely used as packing product because of its lower production efficiency, higher energy consumption and higher cost, so in the future the study on PVA film will improve its production technology.In this article, PVA film was produced by extrusion and casting film technology, and starch also would be blending in PVA to improve strength and reduce cost. Through analysising the influence of glycerol, sol concentration, and starch, the result concluded as:(1) Water and glycerol as plasticizers would cause anti-plasticization by increasing crystal in PVA film, and20-30phr glycerol use level would be the optimal formula in PVA film.(2) Starch would crazing toughened PVA film through a mount of Silver streak, and starch could increase tensile strength5-10MPa, elongation30%-60%, tear strength60-120KN/m.(3) Increasing starch concentration and sol concentration could effectively reduce energy consumption and cost, meanwhile increasing production efficiency, the film of25%sol concentration production efficiency would be1.7times as much as20%sol concentration, and20phr starch could reduce14.7%cost.(4) In the process of extrusion and casting film, the extrusion temperature was in the range of80～98℃, screw speed was in the range of40～50r/min, casting roller temperature was in the range of50～60℃, and its line speed was3m/min, casting crevice was300μm.(5)30phr glycerol,20phr starch,25%sol concentration was the optimal formula, and the film produced by this formula longitudinal and transverse tensile strength was about28MPa, elongation was about200%, both of them were higher than national standard(tensile strength must be higher than14MPa, elongation must be higher than140%).(6) The optimal film is a water soluble film at higher than60℃, and is transparent if it was covered some products, and the film will prevent fat to seeping itself effectively.