Shanghai Daoqin Plastics Co., Ltd.

何 is polyurethane ester?

polyurethane ester is polyurethane acid ester 简称, it is more acid ester and more alcohol reaction formed, in separation upper has many heavy 复 氨基甲 acid ester 基团（—NH—CO—O—）. in combined formed polyurethane ester resin in, remove 氨基甲 acid ester outer, also has 脲, shrink and other 基团. large separation more alcohol and 二异氰 acid ester reaction formed 链段称 is “ soft 链段”, it polyurethane ester relatively good soft property; more acid ester and expand agent formed 链段称 is “ hard 链段”, it polyurethane ester relatively good rigid property and hardness. soft hard 链段组 formed polyurethane ester resin in, 氨基甲 acid ester less 数, therefore is polyurethane ester 未必恰当, from upper 讲, polyurethane ester 乃至异氰 acid ester addition polymerization material.

different type type acid ester and more 羟基化 combined material reaction rear, formed various structure polyurethane ester, from obtain different property polymer/macromolecule material, plastics, 橡胶, coating material, fiber, bonding agent and other.

  polyurethane ester 橡胶

polyurethane ester 橡胶于1940 year in Germany made formed 功, 1952 year rear 开始投入 industrial production, 而我国 is from 60 year in 期开始研 made 并投入 production. polyurethane ester belongs to types specialty 橡胶, polyether or polyester and acid ester reaction made. raw materials types type, reaction conditions and crosslinked methods different has many product types. from chemical structure upper 看, has polyether type and polyester type, from processing methods upper 看, has mixing/compounding type, type, and thermoplastic type types.

combined formed polyurethane ester 橡胶, generally 先由线 type polyester or polyether and 二异氰 ester ester reaction, made formed low molecular weight poly 体, expand reaction formed polymer/macromolecule polymer, rear add crosslinked agent, add hot make its solid 化, formed is 硫化橡胶, this type of methods is poly method or method. can use method —— will type polyester or polyether and 二异氰 acid ester, expand agent, crosslinked agent mixed combined, make reaction 发生, formed polyurethane ester 橡胶.

  thermoplastic polyurethane (TPU) 橡胶（TPU）

thermoplastic polyurethane (TPU) 橡胶（TPU） is types （AB）n type 嵌段线 property polymer, A代 table/sheet polymer/macromolecule amount polyester or polyether （ molecular weight is 1000～6000）, is long 链, B代 table/sheet 含2～12 直链 carbon 原子二 alcohol is short 链, AB链段间 chemical combined is use 二异氰 acid ester.

  polyurethane ester structure and material mechanical properties between 关系

 1, structure

polyurethane ester separation in A链段 make large separation easy 于旋转, polyurethane ester good elastic property, make polymer soft and grade 转变点 decline, hardness and machine strong/high degree reduce. B链段会束缚 large separation 子链 旋转, make polymer soft and grade 转变点 upper rise, hardness and machine strong/high degree improve/increase, elastic property reduce. adjustment A and B between ratio, can made different elastic property and hardness TPU elastomer.

 2, crosslinked structure

polyurethane ester crosslinked structure remove grade crosslinked outer, also must separation hydrogen formed grade crosslinked. polyurethane ester grade crosslinked and type 橡胶 硫化 structure different, it 氨基甲 acid ester 基, shrink 二脲, 脲基甲 acid ester and other 基团规则而间隔 排列 formed rigid property 链段, made tool has 规则 网状 structure, therefore tool has wear resistance can and its it excellent property can. its 次, due to polyurethane ester in has very more 诸如脲基 or 氨基甲 acid ester this category of inner poly can relatively large 基团, therefore separation 子链间形 formed hydrogen tool has very high strong/high degree, hydrogen formed grade crosslinked for polyurethane ester property can has important effect/influence. grade crosslinked make polyurethane ester 橡胶一方面 tool has hot solid property elastomer features, 另一方面 this type of crosslinked also has true positive crosslinked 起, is types crosslinked, crosslinked 状况取决于 temperature degree. temperature degree rise high, this type of crosslinked also decrease low 以至于消失, polymer tool has flow property, can thermoplastic property processing. temperature degree reduce 时, this type of crosslinked also 逐渐恢复并 again formed. a small amount of filler add 入, make separation 子间 距离 increase large, separation formed hydrogen can force decrease low, strong/high degree 便会急剧 decline.

 3, stability property

research table/sheet 明, polyurethane ester in 各基团 stability property high to low is: ester, ether, 脲, 氨基甲 acid ester, shrink 二脲, in polyurethane ester aging process in, is shrink and 脲基甲 acid ester crosslinked fracture, is 氨基甲 acid ester and fracture, 即主链 fracture.

  polyurethane ester material mechanical properties

polyurethane ester elastic property modulus 介于橡胶 and plastics between, it most large features is, tool has hardness, also has elastic property, this type of property can is its it and plastics has.

polyurethane ester separation polyester type and polyether type type, from material property 质进行 comparison, low hardness 橡胶以 polyester type property can relatively good, high hardness 橡胶以 polyether type is excellent. polyester type oil resistant, heat resistant and metal bonding property relatively good, hydrolysis resistant, resistant and antimicrobial property polyether Model/Grade is good.

 1,    ring features

polyurethane ester generally tool has relatively good resistant temperature property, long use temperature degree is 80～90℃, short time can 达120℃ left right. polyurethane ester low temperature resistance property can relatively good, polyester type property temperature degree is -40℃, polyether type polyurethane ester 则达-70～-80℃, low temperature lower hard.

polyurethane ester oil resistant property comparison good, has resistant water property structure different 而异. ester formed reaction can property TPU degradation most is heavy. ester and water 接触时, acid again formed is separation understanding 体 自身 catalytic reaction causes. polyester type polyurethane ester in gas in and wet gas 接触时 understanding 体 程 degree ratio full in water in more 甚. this is is in water in, formed acid 会不断 by 冲走. polyether type polyurethane ester hydrolysis resistant property is polyester type polyurethane ester 3～5倍, ether 基不会 and water reaction. water 侵入导致 polyurethane ester property can decline causes has 两 方面: is water and polyurethane ester in property 基团形 formed hydrogen 键, make polymer separation between hydrogen decrease low, this process is can 逆, drying rear material property also to 恢复. is water make polyurethane ester hydrolysis, process is can 逆.

polyurethane ester in long time day light lower color dark, physical properties reduce. 酶菌也会导致 polyurethane ester degradation, therefore industrial production in use polyurethane ester in add anti agent, outer absorption agent, anti agent and other.  

2,    mechanical properties

tensile strength: polyurethane ester tensile strength relatively high, generally can 达28～42 Mpa, TPU居 in, is 35 Mpa.

elongation: generally can 达400～600%, most large is 1000%.

elastic property: polyurethane ester elastic property comparison good, it rear loss comparison large, therefore hot high. in more bending and high speed negative conditions lower easy loss bad.

hardness: polyurethane ester hardness scope/range relatively its it 橡胶都 wide, most low is Shore hardness 10, its in large more products tool has 45～95 hardness. hardness high 于70 degree 时, tensile strength and strong/high degree high 于天然橡胶, its in 80～90 degree 时, tensile strength, strong/high degree, resistant strong/high degree versus high.

撕裂 strong/high degree: polyurethane ester strong/high degree relatively high, experiment/testing temperature degree rise high to 100～110℃时, resistant strong/high degree and 丁苯橡胶 versus 当.

wear resistance: polyurethane ester wear resistance separation excellent 良, ratio 天然橡胶 high 9倍, ratio 丁苯橡胶 high 1～3倍.

TPU injection molding processing process

its it thermoplastic property material in, processing temperature degree large raw materials melt temperature degree rear, melt main/primary viscous 流态, processing temperature degree high, melt flow property good, processing temperature degree relatively low 时, melt flow property 就差, 甚至于不 flow, melt performance elastic property relatively small. for/regarding TPU之 type elastomer 讲, processing temperature degree high certain temperature degree 时（ separation between crosslinked full understanding remove ）, melt flow property relatively good, melt more more performance viscous property; processing temperature degree low certain temperature degree 时（ separation between crosslinked separation understanding remove ）, melt performance flow property also performance elastic property, is types viscous elastic 体. injection molding 充胶 时候, melt temperature degree relatively high 时, TPU and its it thermoplastic property material 一样, main/primary performance viscous property, product can obtain relatively good outer 形, dimensions stability, deformation small. melt temperature degree relatively low 时, TPU呈现出 viscous elastic property, flow property good, product is 自然 充满 mold cavity, is has elastic property 膨胀而充满 mold cavity, injection molding pressure rear, elastic property outer force 消失, 膨胀 部 separation 恢复形变, therefore shrinkage rate large, dimensions small, deformation large.

therefore, TPU injection molding processing molding process adjustment attention/notes:

1,     processing temperature degree control for product most dimensions, outer and deformation tool has important effect/influence. processing temperature degree need 随TPU grade, mold design specific 情况而定. trend is, need obtain small sink marks rate, need improve/increase processing temperature degree.

2,     slow speed and relatively long time holding pressure 会导致 separation toward, although can can obtain relatively small product dimensions, product deformation relatively large, and toward and toward shrinkage large. large holding pressure pressure also 会导致胶体 in inner pressure shrink, product demolding rear dimensions ratio mold cavity dimensions also need large phenomenon.

3,     injection molding speed degree, pressure 转换 位置 need 设置准确, 位置设置不准确会 increase causes analysis difficult degree, 不利于 fast speed 而准确 进行 process adjustment.

4,     injection molding machine machine type selection need combined 适. small dimensions injection molding product need can can selection machine type small injection molding machine, increase large injection molding 行程, 便于进行位置 control, combined 理 进行 injection molding speed degree, pressure 转换. machine parts, dimensions comparison small, use injection molding machine comparison large, has screw front 进1mm product already 满胶, 根本就无 method 进行位置 control.

5,     当TPU moisture content ultra- 0.2%时, effect/influence product appearance, but also mechanical properties obvious bad, injection molding product elastic property 差, strong/high degree low. therefore in injection molding front in 80℃～110℃ temperature degree lower drying 2～3 small 时.

6,     injection molding machine material 筒 清理 need dry 净, less its it raw materials mixed 入都会导致 product machine strong/high degree reduce. use ABS, PMMA, PE清洗 material most good in injection molding front use TPU water material again one-time, use TPU water material remove material in material material. material 斗清理时 need especially attention/notes material and injection molding machine machine base/seat 连接部 separation a small amount of its it property raw materials 清理, this separation is large more technology as production in easy 忽略 方.

mold design precautions:

1,    sink marks rate positive.

TPU材 material sink marks rate 随 材 material grade different generally in 0.5%～2.0% scope/range inner 波动. currently upper TPU raw materials, large separation supply 商都不 provide raw materials sink marks rate. this is is TPU products dimensions amount relatively its it hard material amount 结果误差 large, injection molding processing process, products thick degree and other for amount has relatively large effect/influence, amount sink marks rate has relatively large scope/range.

sink marks rate main/primary also is 靠 injection molding processing 厂 according to 选定 材 material grade, through stability injection molding process 获取. is comparison sink marks rate data, need using/adopting relatively high injection molding processing temperature degree, ensure injection molding melt separation inner crosslinked can full understanding remove, melt viscous lower injection molding, this amount sink marks rate tool has 参考价 value. ratio 如, has sleeve/set mold, selection TPU is 75 degree, in 180 ℃ processing temperature degree 时, product dimensions combined requirements, product dimensions unstable, deformation large; in 190℃ processing temperature degree 时, product dimensions stability, deformation small, dimensions large. this 时应该选取190℃ processing temperature degree lower product data 计算材 material sink marks rate, rear according to this sink marks rate mold design.

2,    system design

主 runner

因主 runner is pressure most large 方, injection molding pressure understanding remove rear, runner cold material elastic property 膨胀而 increase large retardant force, water viscous front 模, therefore mold design 时应尽 can can add large runner demolding degree. runner small dimensions also can small injection molding machine 射咀孔径, large dimensions increase need outer increase cooling time, long injection molding cycle, therefore demolding degree increase large main/primary shrink short runner long degree achieve. generally 情况主 runner small 端直径约 is 2.5～3.0mm, large 羰直径 is 6.0mm below/following, long degree ultra- 40mm is 宜. runner 末端应设置 and large 端直径稍 large cold 井, cold and water 口.

in injection molding production in 常发现 this 样 一 issues: cold design ratio runner 直径末端 large, cold 胶收集 comparison full, can to comparison good product, water easy 拉断, viscous front 模, need cooling time long. will cold design ratio runner 末端直径 small, water cooling fast, water easy 扣出, cold easy troubleshooting, product quality 差.

cold 井扣针 形式 generally has: 球头形, “Z”形, 倒锥形 and other multiple 形式, lower 面 一 types 倒锥形变异形式 can comparison good solution upper issues, has 兴趣 朋友 can 一试.

due to TPU flow property good, is 避免胶体 through 闸口时出现 喷射 and separation toward 导致 横 toward and toward shrinkage 不一致, gate generally using/adopting large water 口, 闸口部 separation deep degree and wide degree dimensions ratio its it thermoplastic property material dimensions large, separation runner to mold cavity between long degree dimensions need ratio small, 以利于胶体 through. separation dimensions long 闸口会导致充胶时胶体 喷射, effect/influence product appearance.