Shanghai Daoqin Plastics Co., Ltd.

         hot shrinkage film is types in production process in in film toward, toward tensile toward, in use process in hot shrinkage thermoplastic property plastics film. film hot shrinkage property in 1936 year obtain application, most main/primary use film shrinkage packaging easy food. 如今, hot shrinkage technology already development to can use plastics shrinkage film packaging various product, in food material, electronics product, automotive use product, day 化, tool, and other field/area has applications.

         hot shrinkage film production process film molding methods generally separation method and film method. method: 以BOPET hot shrinkage label production process is 例, its production process/workflow is will PET copolymer resin drying 处理, rear add extrusion machine in melt extrusion, through 模头/ cold sheet/slice, rear will sheet/slice add hot to 玻璃化 temperature degree above, melt temperature degree below/following certain 一适当 temperature degree scope/range inner, in outer force function lower, mono toward or di toward 一定倍数 tensile, usually requirements 进行横 toward 3.5~4.0倍 tensile.

         hot shrinkage film film method generally separation is mono method, di method and method. 普通吹 film production process belongs to mono method, due to method control film in toward and toward upper and tensile ratio/proportion, 且吹胀 ratio generally in 2~3 left right, film hot shrinkage rate high, therefore method production product main/primary used for product material in packaging, 如啤酒饮 material, day use electronics product outer packaging and other. di method main applications 于POF film production in. due to film 进行 二次吹胀, therefore can control film in toward and toward upper tensile ratio/proportion, tensile ratio/proportion high, through process formulation control, film shrinkage rate can to 70% above. POF film main/primary application areas in small packaging products in. hot shrinkage film in food in, especially is cold in application, method hot shrinkage film production process 应运而生. due to products for film packaging hot shrinkage stability property requirements high, hot shrinkage use temperature degree low, retardant property can 佳, di method can production combined requirements product. lower heavy 描述 三泡 method hot shrinkage bag production process, technology difficulty/challenge and market and other related 情况.

        三泡 method hot shrinkage bag production process and principle. its method process process/workflow generally lower:

         raw materials additives -- mixed combined uniform --熔 melt extrusion -- more mold extrusion -- film 胚(一泡)-- cooling type -- water add hot -- hot preheating --二次吹胀(二泡)-- cooling type (三泡)--旋转收卷-- crosslinked -- printing -- made bag -- packaging 入库

         its key/critical control lower:

        1)一泡 extrusion: using/adopting lower method extrusion tube/pipe, high poly material 处于熔 melt 状态.

        2)二泡吹胀:胚 tube/pipe more mold extrusion rear, upper through true water sleeve/set cooling, rear hot water or add hot 箱, add hot to 玻璃化 temperature degree above 进行纵 toward tensile, again utilizing pressure shrink gas 进行横 toward 吹胀, ratio and tensile ratio is 3.5: 1 left right.

         this has important concept: ratio and ratio.

        牵引 ratio: is film speed degree and tube/pipe extrusion speed degree between ratio value. ratio is toward tensile 倍数, make film in direction upper tool has toward function. ratio increase large, toward tensile strength 也会随之 improve/increase, film thick degree thin, if ratio large, film thick degree difficult control, has can can will film 拉断, formed film phenomenon.

        吹胀 ratio: is 指吹胀 rear film 泡 直径 and 未吹胀 胚 tube/pipe between ratio value. ratio is film toward 膨胀倍数, upper is for film 进行横 toward tensile, tensile for plastics separation generate 一定程 degree orientation function, ratio increase large, from make film toward tensile strength improve/increase. is, ratio can large can small, large easy formed film unstable, film easy 出现皱折;太 small formed product shrinkage rate 不够. therefore, ratio 应当同牵引 ratio combined 适当才行.

        二泡 process material principle is: 当 high poly material high elastic 态时, for its tensile orientation, rear will high poly material cold 至玻璃化 temperature degree below/following, separation orientation by 冻结, material product packaging process in for its add hot 时, due to separation hot generate force 松驰, separation 恢复原 状态, generate shrinkage.

        3)三泡定 type:二次吹胀 rear film also 需进行定 type 处理, rear 收卷. hot shrinkage film in normal temperature lower 储存, generate shrinkage, therefore type versus key/critical.

        4) hot shrinkage film also need crosslinked 处理, generally using/adopting electronics crosslinked, separation is in crosslinked and crosslinked. crosslinked film can make its property can to large degree improvement, not only significantly improve/increase film force property can, resistant ring force cracking property can, chemical resistant product property can, resistant creep property and electrical property can and other comprehensive property can, but also non obvious improve/increase resistant temperature and other grade, this process process is hot shrinkage bag production key/critical process control 点之一.

        5)三泡 method hot shrinkage film and hot shrinkage film production process key/critical difference in 于: method 吹涨时 high poly material is in melting point above 进行纵 toward and toward tensile, 而三泡 method is will tube/pipe temperature degree control in 玻璃化 temperature degree above, melting point below/following, rear tensile and 吹涨.

        三泡 method hot shrinkage film raw materials selection. due to hot shrinkage film using/adopting is lower water cold production process, therefore raw materials generally selection film grade can. in packaging product rear hot shrinkage process in, generally using/adopting hot water, or outer add hot 3~5秒. is decrease/reduce temperature degree for cold surface effect/influence, therefore requirements film hot shrinkage temperature degree low, therefore selection relatively low density polyethylene (PE), metallocene property polyethylene (PE) and EVA and other raw materials, can in 90℃甚至 more low temperature degree achieve 40% above hot shrinkage. meanwhile also need film property can need good, shrinkage rate need large, shrinkage force low, 以避免血 water extrusion.

         according to packaging inner material types type and shelf life requirements, generally oxygen gas retardant property can separation is retardant thermal insulation shrinkage bag, high retardant thermal insulation shrinkage bag and retardant thermal insulation shrinkage bag. retardant raw materials generally selection PVDC, EVOH, copolymer nylon. therefore product structure separation is lower basic type 别:

        1)无 retardant oxygen property structure: (MPE+EVA)/ LLDPE/ (MPE+EVA)

        2) retardant property structure: PA/TI/(MPE+EVA)

        3) high retardant property structure 之一: PA/EVOH/TI/(MPE+EVA)

        4) high retardant property structure 之二: (MPE+EVA)/ EVA/PVDC/EVA/ (MPE+EVA)

         in using/adopting EVOH and nylon retardant 隔层时, generally design is for structure, nylon design in outer 层, this inner outer material melting point versus very large, made bag. for structure product inner outer material temperature large, therefore need for film crosslinked, improve/increase film resistant temperature property can, from easy made bag.

         this need focus/key point lower crosslinked process. is has polymer/macromolecule material can electronics crosslinked, and crosslinked and understanding is meanwhile 进行, has 一方面 is main/primary, this has electronics crosslinked type and understanding type polymer separation. polyethylene (PE), EVA and other belongs to can 进行辐射 crosslinked material 质. PVDC in 进行辐射 crosslinked rear 会发生 yellowing, effect/influence product show/display 效果, currently is 困扰业界 一 difficult 题. has company product in 此方面 solution very good, use is in crosslinked, its it company use is crosslinked, film production formed rear again crosslinked. crosslinked generate another issues, hot shrinkage film in electronics crosslinked 时, generate property gas 体--臭 oxygen, due to in bag inner, method 排出, tube/pipe combined food safety requirements, has 时会遭 to 客户 拒绝.

        三泡 method hot shrinkage bag market outlook/prospects. according to related 报道, food packaging bag year 20% speed degree formed is growth most fast soft packaging market. in full ultra- 百 100 million 份鲜肉 packaging in, has 30% above ratio/proportion use is bag packaging. can forecast, hot shrinkage packaging bag will formed is high speed growth soft packaging market. hot shrinkage bag main/primary advantages lower:

        1. shrinkage decrease/reduce packaging outer more material, make packaging more 紧贴, show/display good, improves product sales force;

        2. hot shrinkage bag hot shrinkage rear 无褶皱, inner material non 常贴体, remove its generate fine water phenomenon, meanwhile low shrinkage force most large degree decrease/reduce water 渗出;

        3. hot shrinkage bag retardant has retardant oxygen gas 渗透, long products shelf life;

        4. hot shrinkage bag can has retardant water 份 流失, maintain product has 口味, meanwhile is enterprise cost;

        5. hot shrinkage packaging product and outer 界 接触, 避免 二次污染, use more safety.

         currently PVDC hot shrinkage bag application scope main/primary in cold packaging, also has separation used for need high retardant property product processing field/area. according to USA cold packaging development history, can China future packaging cold development direction. world large rear is ultra- 市 development, 开始出现 film packaging cold 鲜肉, its main/primary used for ultra- 市 rear 店, anti 止鲜肉 separation rear process water dispersion 失, this type of packaging still in color 改变, packaging 渗漏, 保存期限 short issues. PVDC材 material and application, lower 20 year (1950～1970) hot shrinkage packaging materials 逐渐演变 to retardant property shrinkage bag, from long products 保存期限, make can more elastic property, efficiency adjustment production and 库存. USA main/primary 保鲜牛肉 supply 厂商都 is year use true shrinkage bag and in packaging factory 先驱者, this large supply amount 占总饲养牛 屠宰 amount 3/4, its in 85% product using/adopting true shrinkage packaging. USA true shrinkage packaging already its 牛肉总 output/production volume 90%.

        普通无 retardant thermal insulation shrinkage bag main applications cold 藏牛羊肉 product packaging in, due to property good, and can in lower degree below/following cold in has anti product dry consumption, product already in inner and other 北方 区广泛 use. nylon, EVOH hot shrinkage bag main applications 于火腿 and other dry products field/area. 我国 火腿消费 amount high, is in Europe, and 俄罗斯, this packaging use amount is non large.

         hot shrinkage packaging bag use scope/range positive 越 越广, very good 例子就 is products. 我国 卤 products basic is as processing methods, 随 国家 and for food safety heavy 视, food processing 厂开始 production low temperature slow 煮 肉 products, and has non good market reaction. low temperature slow 煮Sous-vide源自 method 语, is “under vacuum”-“ true 空烹调 method ” 意思, is 以科学化 research, 找出每 types 食材 蛋白 fine hot temperature degree scope/range, from 而计算出爆破 temperature degree inner, use more long time material most good. “煮熟” most methods, is will its can high temperature plastics bag, 抽尽空 gas true 空状态 rear, 放进计算 good temperature degree temperature hot water in 浸泡规定 time, let material in hot water in slow slow 泡熟, material can in most combined temperature degree in most more acid 钠, most 原汁原味, and 营养也 is most 佳状态. currently inner already has more food processing in use hot shrinkage bag production low temperature slow food. has versus hot shrinkage bag market outlook/prospects 会越 越广泛.