Shanghai Daoqin Plastics Co., Ltd.

        众 周知, is film 厂家普遍存 in issues. for transparent bag 说, obvious effect/influence transparent bag appearance. for requirements printing quality relatively high bag 说, especially is large 面积 胶 bag printing, 晶点 造 formed “白点” waste product, is bag industrial production process upper relatively large ratio/proportion loss consumption. therefore, control generate, remove formed 因, is improve/increase bag industrial technology water important process step/link.

        1, what is 晶点

        晶点实际 upper is “ degree polymer ”, 即: “晶点”部位 polymer molecular weight need high 于周围同 types polymer molecular weight. due to molecular weight high, therefore, 晶点部位 polymer tool has relatively high melting point #FormatStrongID_2# in 熔化时, melt tool has relatively high viscosity. 晶点部位 polymer in film or 流延时, can and 周围 同 types polymer versus uniform dispersion, mixed combined, in melt formed or formed film rear, 先于周围 同 types polymer solid. therefore, formed “箭头状” or “球状” degree polymer solid 体, upper by is “晶点”.

        2. generate causes

         material material causes

        (1) polymer in has catalytic agent;

        (2) polymer melt viscous production equipment (包括 polymerization equipment and film equipment) metal surface, in high temperature lower, 残留;

        (3) catalytic agent for polymer 继续进行 catalytic polymerization function, therefore formed degree polymer;

         polymer in oxygen, make polymer melt generate 晶点(add 入一定数 amount antioxidant, has anti oxygen for generate function).

         process causes

        (1)由 polymerization process formed 晶点. different polymerization equipment and process, for 晶点 生 formed has different effect/influence. 例如: 一 名厂 raw materials, production technology high, polymer in catalytic agent content low, equipment structure good, therefore, raw materials 本身 含 晶点 less. quality relatively raw materials, production technology and equipment issues, formed raw materials 本身 含 晶点 more.

        (2)由 process formed 晶点. 例如: good molding equipment made film, less. equipment made film, more.

        3. decrease/reduce or basic remove methods

        综 upper 述, in film made process in remove 晶点, main/primary has 两 途径:

        (1) improve/increase processing equipment fine degree (例如: will 滤网改 is 120目, or 150目- used for ultra- film).

        (2) in production process in add surface lubricant, make by processing polymer melt can viscous 滞于吹 film equipment surface.

         from production process upper 说, use relatively fine can remove large polymer in 原生晶点, meanwhile can remove equipment screw and 炮筒部位因 polymer viscous screw surface formed 晶点, issues is equipment back pressure therefore improve/increase, for certain molding equipment 说, difficult to. therefore, 依靠勤换滤网, can for control provide 帮助.

         to currently is 止, comparison has 效 晶点 control is using/adopting high property can fluorine process additives. high property can fluorine process additives, due to it polymer separation tool has high property features, make it can from type polymer (例如: PE, PP) melt in speed 溢出, viscous equipment metal surface, from remove polymer melt in equipment metal surface viscous 滞层.

         therefore, polymer melt can 持续匀 speed by front 进, remove viscous metal surface polymer melt long time hot phenomenon, anti 止 残留 catalytic agent for polymer polymerization, most anti in film molding processing process in generate 晶点.

        另一方面, due to fluorine process additives can viscous 附于滤网 surface, make polymer melt 流经滤网 retardant force decline. therefore, fluorine process additives use, is using/adopting relatively fine provide process conditions. relatively fine using/adopting, for remove polymer production generate 原生晶点, is important process measures.