Shanghai Daoqin Plastics Co., Ltd.

polyolefin foam film blow molding fault/failure troubleshooting fault/failure formed and countermeasures foam structure 不规则(1) blow molding process conditions control 不当. 应适当 adjustment. (2) melt pressure low. troubleshooting methods is: ① increase screw speed. due to foaming agent separation understanding and its in machine inner time formed positive ratio, meanwhile also screw speed 支配, is 说, improve/increase screw speed, can make machine and inner maintain pressure, made growth, this is obtain uniform, fine foam structure necessary conditions. speed low, film 面会出现鲨皮斑. screw speed can high, 否则会引起 melt 破裂. ② reduce mold temperature degree. is make foaming in export 区开始, 一方面 need improve/increase extrusion pressure, 另一方面应维持稍 low and machine temperature degree, make export pressure and other or large foaming pressure, anti 止提早 foaming. ③适当 decrease small sheet/plate 孑LB艮直径. ④ using/adopting melt flow rate relatively low resin. production foam blow molding film commonly used resin is low density polyethylene (PE) (LDPE) and low density polyethylene (PE) —醋 acid ethylene copolymer, for/regarding low density polyethylene (PE), melt flow rate 以0．25—2．0g／min is 宜, this type of low melt flow rate resin, tool has relatively high melt strong/high degree and viscous property. in melt flow rate relatively low low density polyethylene (PE) in add 入5％—10％ 醋 acid ethylene, can increase film elastic property and surface force, foam film property can. ⑤适当 decrease small 口模间隙. (3)口模挂 material. troubleshooting methods is: ① shrink short 口模定 type long degree. type relatively long 会发生 gas expand dispersion phenomenon, is material 流 定 type will generate pressure drop. ②清 remove machine inner material 杂质. (4)熔 material in machine low pressure 区滞流. troubleshooting methods is: ① decrease small machine amount. design machine 头时, in maintain material uniform flow front lower, amount decrease small machine amount, anti material in machine inner and pressure. ② increase screw speed. (5) in machine 头支架区 formed 泡不规则. troubleshooting methods is: ① using/adopting 螺旋式底部进 material, shrink short type or type small machine 头. due to type machine 头支架周围容 easy generate pressure 变化, make gas from material in 逸出, make film surface coarse and 不规则, generally using/adopting. ②适当 increase machine pressure 泡孔塌瘪(1)熔 material flow defect. 应改进 machine runner structure and adjustment machine temperature degree or extrusion speed degree. (2) resin melt flow rate high. more resin. (3)泡 tube/pipe cooling fast. reduce cooling speed degree. value heavy is, cooling is molding process in relatively difficult control step/link, it not only 直接关系 to film production speed degree, but also effect/influence film thick degree uniform property. usually using/adopting decrease pressure ring cooling, in ring export has gas toward sheet/plate, make cold gas tube/pipe surface flow, utilizing gas decrease pressure degree make tube/pipe 直径自动 adjustment. due to cold and hot 会导致泡孔 shrinkage and 出现皱纹, therefore, for tube/pipe must uniform slow cooling. (4) foaming agent and resin mixed combined defect. 应改进 mixed combined conditions. generally, will foaming agent add resin in has types methods, dry powder mixed combined method, liquid dispersion method and material method. separation lower: ① dry powder mixed combined method. powder foaming agent and pellets resin mixed combined methods most 经济, easy dispersion uniform, in material upper block, formed large 泡孔, heavy make tube/pipe shrink small 甚至塌瘪. for 此, can in resin surface spray coating 一层矿 material 油, improvement resin and foaming agent adhesion property. ② liquid dispersion method. liquid foaming agent can 直接泵人 extrusion machine, therefore must control extrusion speed degree and speed degree, anti film density and structure 发生变化. ③母 material method. material method production cost relatively high, it dry powder mixed combined method series defect. due to made material is types foaming agent concentrated shrink material, can make foaming agent full separation understanding has control large small. again 则, can ensure raw materials tool has foaming agent content, suitable for 自动化 add material film has or 破裂(1) foaming agent use amount more. 应适当 decrease/reduce. (2) machine temperature degree high. 应适当 reduce. (3) resin melt flow rate high. more resin or reduce molding temperature degree. (4) foaming agent separation understanding fast. troubleshooting methods is: ①适当 increase screw speed. ②适当 decrease/reduce foaming agent and active agent use amount. active agent function is accelerated foaming agent separation understanding and reduce separation understanding temperature degree. nitrogen 二甲酰 amine (AC) foaming agent use active agent has metal salt type, oxidation zinc, hard acid zinc and other. generally is, foaming agent pellets degree small or surface large, separation understanding temperature degree low. 但实践 table/sheet 明, different degree foaming agent, in add hot conditions lower, 于同一 temperature degree scope/range gas 体, in add active agent rear in scope/range inner different speed degree separation understanding, separation understanding speed degree can use foaming agent and active agent use amount ratio add control. generally ratio/proportion is 1: 1时, relatively good film table/sheet defect (1) foaming agent use amount more. 应适当 decrease/reduce. commonly used foaming agent is nitrogen 二甲酰 amine (Ac), its use amount generally according to film density 确定, add 入0. 5％(quality percentage)时, film density can decline 30％—40％. (1) molding speed degree low. 应适当 increase screw speed, improve/increase extrusion speed degree. (3)口模 molding melt pressure loss relatively large. troubleshooting methods is: ① shrink short 口模定 type long degree. ② increase large screw long ratio. generally, screw long ratio 以20: 1 or more large is 宜. in addition, for/regarding polyolefin 说, screw add material long degree is 直径 2倍, pressure shrink is 直径 14倍, 均化段 is 直径 4倍. screw pressure shrink ratio can small 于3. 5: 1. ③适当 increase screw speed. (4) machine temperature degree low. 应适当 improve/increase