Shanghai Daoqin Plastics Co., Ltd.

         foaming mechanism

         in PVC foaming products in, add ultra-high molecular weight polymer 目: is is promote PVC 塑化;二 is is improve/increase PVC foaming material material melt strong/high degree, anti bubbles combined 并, to uniform foaming products;三 is is ensure melt tool has good flow property, to appearance good products. due to different foaming products production product different, use equipment, process, raw materials and lubricated system has 差异, therefore development tool has different property can foaming adjustment agent, meet/satisfy use different demand.

         foaming material 定义

         foaming plastics foam plastics, is plastics is basic separation, has a large amount of bubbles, can is gas is filling composite/compounding material.

         foaming sheet/slice classification

         according to foaming rate different, can separation is high foaming and low foaming, according to 泡体质 soft hard degree, can separation is hard 质, semi hard 质, soft foam plastics. according to structure can separation is foam plastics and foam plastics. generally Common PVC foaming sheet/slice belongs to hard 质闭孔 low foaming sheet/slice 材.

        PVC foaming sheet/slice has chemical resistant 腐蚀, weather resistance, flame retardant property and other advantages, widely used in more 方面, show/display sheet/plate, 标记, 广告牌, sheet/plate, construction use sheet/plate, furniture use sheet/plate and other.

         evaluation foaming sheet/slice quality key/critical factors

         for foaming material 说, large small and uniform degree is effect/influence sheet/slice quality key/critical factors. for low foaming sheet/slice 材, small uniform, foaming sheet/slice tough property good, strong/high degree high, surface quality good. from reduce foaming sheet/slice density 方面考虑, has small uniform has 进一步 reduce density can can property, large dispersion very difficult 进一步 reduce density.

        PVC foaming process control key/critical 点

         plastics foaming molding separation is process: bubbles 核 形 formed, bubbles 核 膨胀 and solid 化. for/regarding add chemical foaming agent PVC foaming sheet/slice 材 说, bubbles 核 膨胀 for foaming sheet/slice quality 起决定 property effect/influence. PVC belongs to separation 子, separation relatively short, melt strong/high degree low, in bubbles 核膨胀 formed bubbles process in, melt 不足以包覆住 bubbles, gas easy combined formed large 泡, reduce foaming sheet/slice product quality.

         improve/increase PVC foaming sheet/slice quality key/critical factors is improve/increase PVC melt strong/high degree. from polymer/macromolecule material processing features analysis, improve/increase PVC melt strong/high degree methods has multiple, most has methods is add improve/increase melt strong/high degree additives and reduce processing temperature degree. PVC belongs to non material, melt temperature degree improve/increase melt strong/high degree reduce, 反之随 melt temperature degree reduce melt strong/high degree improve/increase, drop temperature function has 限仅起 to function. ACR type processing agent has improve/increase melt strong/high degree function, its in foaming adjustment agent most has 效果. melt strong/high degree foaming adjustment agent content increase improve/increase. generally 而言, need screw has dispersion mixed combined can force, add high degree foaming adjustment agent for improve/increase melt strong/high degree more obvious.

         processing additives in PVC foaming sheet/slice in function

        ACR type processing additives has promote PVC熔 melt, improve/increase surface light degree, improvement melt elastic property, reinforcement melt elongation and strong/high degree function. has 利于包覆 bubbles, anti 止泡孔塌陷. foaming adjustment agent molecular weight and use amount for foaming sheet/slice density has very large effect/influence: molecular weight improve/increase, PVC melt strong/high degree improve/increase, foaming sheet/slice density can more low, and improve/increase adjustment agent use amount has same function. this function tool property 关系, increase molecular weight or improve/increase use amount, for reduce density function is non obvious, density will 趋于恒定.

         foaming adjustment agent and foaming agent between in important 关系, foaming sheet/slice density and foaming adjustment agent in balanced 点, in this balanced outer, foaming sheet/slice density foaming agent content effect/influence, 维持恒定, is increase foaming agent use amount can reduce density, this phenomenon causes is in amount foaming adjustment agent use amount lower, PVC melt strong/high degree is has 限, amount gas 体导致泡孔塌陷 or combined 并.

        PVC foaming process in Common issues

         in PVC foaming sheet/slice extrusion process in, to issues basic can is 4 type,

        1. is stability property issues;

        2. is melt strong/high degree issues;

        3. is lubricated issues;

        4. is dispersion issues.

         this type issues especially is front type issues versus made 约, effect/influence, from surface phenomenon has very difficult separation 清楚, need 说方观察 analysis, to issues 根源才 can solution.

         stability property issues: stability property 不足, effect/influence sheet/plate 面, sheet/plate 面发黄, foaming sheet/slice property large.

         melt strong/high degree issues: melt strong/high degree 不足会导致 foaming sheet/slice large, 纵切面泡 very long. melt strong/high degree is 否不足, most 直接 办 method is to rear use 手指按 pressure in in upper sheet/slice 材, melt strong/high degree good pressure can to elastic property. pressure rear very difficult elastic 起, melt strong/high degree relatively 差. is screw structure and cooling methods relatively large, very difficult temperature degree is combined 理, generally 说, in extrusion machine negative inner, 3—5区 temperature degree low is good. in foaming pipe/tube in need obtain foaming uniform products, need ensure PVC material material has good melt strong/high degree.

         lubricated issues: lubricant separation is outer lubricant and inner lubricant, outer slip has demolding, for sheet/plate surface light property has benefits, outer slip less, extrusion machine 5区 temperature degree easy control, easy rise temperature, this 会导致 combined temperature degree high, sheet/plate in large 泡, 串泡, and other issues, sheet/plate surface light slip; outer slip more, 析出会变 严 heavy, performance in mold inner structure and sheet/plate surface outer slip 析出, performance is certain phenomenon in sheet/plate upper 不定期 回移动. inner slip has 利于塑化 and melt flow property, inner slip sheet/plate difficult control thick degree, performance is sheet/plate in thick thin; inner slip more, easy combined temperature degree high phenomenon. dispersion good belt/tape sheet/plate surface light slip phenomenon.

         process temperature degree control issues: upper to issues belongs to property issues, is 基础, is deep issues. versus for/regarding upper issues, process temperature degree control need more, is surface issues, temperature degree control good, 会诱发根本 issues 出现. improve/increase processing process temperature degree, material stability time reduce, stability property issues;原 has lubricated balanced by 打破, generally performance is outer lubricated 不足, especially is rear outer lubricated, improve/increase outer lubricated add amount; temperature degree improve/increase 也会导致 melt strong/high degree reduce, foaming sheet/slice 材泡孔 increase large, 泡孔数 amount decrease/reduce, sheet/slice 材发脆 easy fracture; temperature degree improve/increase reduce melt strong/high degree reduce melt viscosity, viscosity reduce dispersion can force reduce, for dispersion can force strong/high screw 而言, has 时会出现 dispersion non-uniform.