Shanghai Daoqin Plastics Co., Ltd.

PVC（ polyvinyl chloride (PVC) ）   UPVC（ hard polyvinyl chloride (PVC) ）                                      

英文名: Polyvinylchlorid,

hot property material material, generally separation is hard 质PVC and soft 质PVC, its difference in raw materials in add increase agent how much, less 于10% is hard 质, more 于30% is soft 质.

material material features:
1.无 obvious melting point, 60℃变 soft, 100℃-150℃ viscous elastic 态, 140℃熔 melt molding temperature degree scope/range narrow, heat stabilized property 差, easy separation understanding, 170℃ separation understanding speed, soft 化点接近于 separation understanding 点, separation understanding 释放于HC1 gas 体. its injection molding process property relatively 差, causes is high temperature degree or long hot time very easy make PVC separation understanding.

injection molding process conditions
1, product amount need has or 突变, thick degree force 求变化不 large, anti 止出现PVC understanding drop 变质. mold has 10 above 拔模斜 degree, 予留约0.5% shrinkage amount. bbs.6sq.nety*kXnbrR
2, mold injection ratio 射咀孔略 large, ratio runner 交错处直径 large, make PVC material mold cavity 不滞留 and pressure balanced. amount using/adopting gate, make 熔渣不会流入 product and runner in temperature degree reduce, easy molding.
gate design in product most thick 壁处, degree 足够, long degree most good in 6—8mm between, make PVC material 流入畅顺. mold temperature degree has cooling water control plant/unit, make mold temperature can in 30℃~60℃ between can 控. mold surface light 洁, anti 腐蚀.

UPVC injection molding machine specialized injection equipment

UPVC due to melt viscosity large, easy separation understanding, separation understanding material for iron has function, its injection molding must specialized 塑化部 parts and temperature system.
1, screw material 筒组应 is is PVC design manufacturing, screw design amount need low 剪切, anti hot, runner need light slip, can has 死角, anti material separation understanding, screw machine need anti 止腐蚀. surface hard 铬.

2, injection molding PVC product melt temperature degree temperature degree control 严格, using/adopting plant/unit. 1.

injection molding process 应 attention/notes below/following 事项:

quality 1, injection process in machine temperature degree control in 170-190℃ between. material temperature degree to setting temperature degree 时, 应起动鼓风 machine cooling drop temperature, rise temperature 时, again 停止吹风 add hot, anti 止PVC hot 变质.

2, screw speed 应因直径 different 而异. generally 直径＜60mm, speed is 50-70rpm; 直径＞70mm, speed is 20-50rpm, anti 止剪切 force large 而出现PVC degradation.
3, back pressure control in 1Mpa left right, high back pressure generate large force, make PVC hot separation understanding. meanwhile in process using/adopting more grade back pressure control. 开始时, screw has long degree long, back pressure relatively low, screw has long degree decrease/reduce, 应适当 increase back pressure hot amount decrease/reduce. material front small 段, also reduce back pressure, anti 止漏涎.

4, must has other plastics PVC raw materials in, 引起PVC raw materials 变质. especially is injection molding other raw materials 时, need 先清洗 dry machine and screw inner plastics, can injection molding PVC product. （ use PS material screw, machine 筒）
5, machine front need will PVC material full 打净, long time machine, is anti 止PVC腐蚀 machine, application PS material dry screw, machine 筒.

6, 当PVC material time ultra- 6 month, ring high temperature, wet, use front application 60-80℃ temperature degree dry 1-2 small can use.
  typical applications scope/range:
 
    water pipeline, use pipeline, 房屋墙 sheet/plate, use machine housing/shell 体, electronics product packaging, medical devices, food packaging and other.
 
    injection molding process conditions:
 
    drying 处理: usually need drying 处理.
 
    temperature degree: 185-205C
 
    mold temperature degree: 20-50C
 
    injection pressure: can large to 1500bar
 
    holding pressure pressure: can large to 1000bar
 
    injection speed degree: is 避免材 material degradation, generally need use versus injection speed degree.
 
    runner and gate: has gate can use. if processing relatively small parts, most good use type gate or 潜入式 gate; for/regarding relatively thick parts, most good use gate. type gate or 潜入式 gate most small 直径应 is 1mm; gate thick degree can small 于1mm.
 
    chemical and material features:
    rigid property PVC is use most plastics material 之一. PVC材 material is types non crystallization property material. PVC材 material in use in add stabilizer, lubricant, processing agent, color material, impact resistant agent and its it additives. PVC材 material tool has easy property, high strength, resistant gas 侯变化 property and excellent 良 几何 stability property. PVC for oxidation agent, also agent and strong/high acid has very strong/high resistant force. however it can by concentrated oxidation acid concentrated acid, concentrated acid and suitable and 芳香烃, chlorine 化烃接触 场 combined. PVC in processing 时熔化 temperature degree is non important process parameters, if parameters will 导致材 material separation understanding issues. PVC flow features versus 当差, its process scope/range very narrow. especially is large molecular weight PVC材 material more difficult processing （ this type of material usually need add lubricant improvement flow property ）, therefore usually use is small molecular weight PVC材 material. PVC shrinkage rate versus low, generally is 0.2-0.6％.