Shanghai Daoqin Plastics Co., Ltd.

         metallocene polyethylene (PE) film features

         metallocene polyethylene (PE) is use metallocene catalytic agent reaction made polyethylene (PE) material, metallocene (mPE). and 普通 齐格勒- nano catalytic agent made LLDPE versus ratio, mPE tool has versus for relatively narrow molecular weight distribution and relatively uniform formed distribution, therefore made film strong/high degree high, toward strong/high degree uniform property good. due to molecular weight distribution narrow, low separation material content less, therefore resistant chemical and resistant property can good, film viscous property low; meanwhile has ultra-high separation material, therefore relatively less. mPE film tool has excellent material mechanical properties, ratio 如: resistant 穿刺, resistant impact, force high, good and other features. mPE film hot property can very good, temperature degree low, hot temperature degree scope/range wide, melting point value low, shrink short hot time, property can good, fracture phenomenon large large decrease/reduce. in addition, mPE film also tool has food packaging need anti 潮, gas, resistant oxidation, oil resistant, resistant 冻, resistant 蒸煮, chemical resistant 腐蚀, 无毒, 无味, effect/influence food formed separation, maintain food 香味, printing property can good, easy and other features, therefore formed is high property can packaging film commonly used resin material. generally property LLDPE film in 油脂存 in lower easy generate 迁移, oxidation, in alkali, acid or strong/high force surface active property agent function lower, hot 封焊缝往往会破裂, formed 污染. 而mPE film tool has LDPE, LLDPE, PP, EVA and other film and more advantages, currently positive in 逐步取代一部 separation packaging materials, it will excellent property can in packaging industry versus important 位.

         material selection and formulation design

         due to mPE resin in film process in for process, equipment has requirements, mPE film production cost to made 约. in production process in, using/adopting mPE/LLDPE blending extrusion blow molding methods obtain property can excellent packaging materials, reduce film comprehensive cost, make melt viscosity decline, to screw decrease/reduce, from decrease light 驱动载荷, make large production film achieve. high property can packaging film production ratio generally mPE is 60%, LLDPE or 者LDPE is 40%时, its cost, production process and property can to relatively 理想 状态.

         high property can packaging use mPE film production process control

         metallocene polyethylene (PE) resin due to its molecular weight distribution and formed distribution, 决定 该 polymer processing process processing equipment and 传统材 material has different. in metallocene film production process in, must ensure equipment positive 常运行 and control good process conditions, to stability product quality 目.

        1. production process process/workflow: mPE film production process and polyethylene (PE) film process basic same, process conditions control has difference. process process/workflow large lower: material -搅拌- extrusion -吹胀- cooling - electrical 晕-牵引-收卷-检验- packaging.

        2. blow molding process control: due to currently metallocene polyethylene (PE) resin price high 于普通 polyethylene (PE) resin, is reduce cost, using/adopting mPE and general purpose grade LLDPE or 者LDPE resin mixed combined use. raw materials amount extrusion machine add material 段时, resin 处于熔 melt stage/phase, viscosity increase large, through screw 传递扭矩, electrical machine electrical upper rise. if control good formed machine or other phenomenon 出现, machine inner material material temperature degree 也随之 upper rise, melt export 模时造 formed 牵引不平稳, 出现破 film, film, film unstable, effect/influence film wide and thick thin uniform property. if drop temperature, film 塑化不 good, more, transparent degree 差, film force property can decline, film relatively hard, coarse 糙. and other film composite/compounding 时出现 local shrinkage, 脱层, hot 封效果差 and other series issues. 因而mPE blow molding process most good 遵循: low - high - in - in temperature extrusion process 规律, from make melt uniform, material 平稳, 牵引, positive 常. this 样, in add material 段应当 maintain low temperature, ensure material and and strong/high large force; in pressure shrink 段应迅 speed rise temperature, make resin front melt, decrease/reduce melt viscosity increase large generate ultra- 扭矩 reaction; melt 进入均化段应 using/adopting drop temperature method, 便于转移 more more hot amount 积累, make material material 处于平稳 viscous 流状态, ensure melt through 滤网, formed stability tube/pipe film, melt phenomenon, is rear 面 牵引, cooling good 基础.

         cooling is mPE film processing in very important ring, due to mPE resin melt extrusion temperature degree ratio 传统LLDPE high crystallization temperature degree also ratio LLDPE low, and 时转移 melt hot amount especially important. using/adopting di ring and dispersion hot meet/satisfy process requirements. 适宜 吹胀 ratio has film cooling, improve/increase film orientation, ensure film thick thin property. in mPE film production process in ratio maintain in 1.8-3.5 between is 佳, high degree control in 2D(D is machine 头口模直径) left right, film comprehensive quality ensure.

        3. equipment requirements: mPE resin in extrusion machine rear material material from pressure to melt, material material 进入熔 melt in melt viscosity increase, material material scratch force increase large, formed screw increase large, generate pressure 传递, extrusion machine 驱动部 separation very large 载荷, make machine electrical rise high, in equipment type 时, must selection 驱动功 rate can 足够承受 production in 出现 扭矩 and equipment. in production process in, control combined process conditions can in scope/range inner improvement machine 承受 载荷, ensure production positive 常进行.

         extrusion machine screw long ratio selection is mPE film production equipment key/critical, selection screw long ratio combined can production excellent mPE film, meanwhile can ensure production can force achieve, from decrease/reduce obtain 一定 收益. currently for mPE film processing need using/adopting screw technology parameters method 并不一致, extrusion machine screw has extrusion pressure, make screw in pressure shrink tool has 足够 剪切 function;进入均化段 rear also must decrease/reduce 剪切, make melt 松弛, speed hot amount, fast speed 出模以 stability production can force. generally screw long ratio selection in 25: 1–32: 1 between can ensure mPE film output/production volume and product quality.

        结语

         metallocene polyethylene (PE) material due to its excellent property can already by application to food packaging and industrial packaging field/area. large metallocene supply in rise grade technology, development new generation metallocene material, force to property can, degree, processing, hot and other 各方面 balanced. different metallocene catalytic agent to metallocene property can same, use can according to product demand selection combined metallocene material.