Shanghai Daoqin Plastics Co., Ltd.

transparent plastics specific selection

transparent plastics property can and injection molding process process

transparent plastics parts defect and solutions

一, transparent plastics specific selection

（1） day use transparent type material

1. transparent film type: packaging use PE PP PS PVC and PET and other ,农 use PE PVC and PET and other;

2. transparent sheet/slice: sheet/plate type use PP PVC PET PMMA and PC and other;

3. transparent tube/pipe type: use PVC PA and other

4. transparent bottle type: use PVC PET PP PS and PC and other

（2） lighting device type material

main/primary used as lamp covers , commonly used PS  modified PS AS PMMA and PC and other

（3） optical device type material

1. hard 质镜体 main/primary use CR-39 and J.D两 types

2.隐形眼镜 commonly used HEMA

（4）玻璃 type material

1.交通玻璃 commonly used PMMA and PC两 types

2. construction commonly used PVF and PET

（5） solar energy material

commonly used PMMA PC GF-UP FEP PVF and SI and other

（6） light material

芯层 use PMMA or PC,包覆层 is fluorine polymer fluorine methacrylic acid ester type

（7） light material

commonly used PC PMMA

（8） transparent 封装材 material

surface increase hard PMMA FEP EVA EMA PVB and other

二, transparent plastics property can and injection molding process process

transparent plastics must has high transparency degree, strong/high degree and wear resistance, can impact resistant, heat resistant parts need good, chemical resistance need excellent, water absorption need small, has this can in use in can meet/satisfy transparent degree requirements long 久不变, commonly used transparent plastics has:

1. polymethyl methacrylate (PMMA) （即俗称亚克 force or has machine 玻璃, 代号PMMA）

2. polycarbonate (PC) （代号 PC）

3. terephthalic acid ethylene glycol 脂（代号 PET）

4. transparent nylon

5.AS（ propylene styrene copolymer ）

6. polysulfone (PSU) （代号PSF）

1） property can comparison

generally requirements products still selection PMMA is 主, 而PET due to need tensile can to good mechanical properties, therefore more in packaging, container in use .

2) injection molding process in process features

i.PMMA process features

PMMA viscosity large, flow property 稍差, therefore must high material temperature, high injection pressure injection molding 才行, its in injection temperature degree effect/influence large injection pressure, injection pressure improve/increase, has improvement product shrinkage rate. injection temperature degree scope/range relatively wide, melt temperature degree is 160℃, separation understanding temperature degree 达270℃, therefore material temperature adjustment scope/range wide, process property relatively good. improvement flow property, can from injection temperature degree 手. impact property 差, wear resistance good, easy 划花, easy 脆裂, improve/increase mold temperature, improvement cold process, this defect.

ii.PC process features

PC viscosity large, melt material temperature degree high, flow property 差, 回此必 must relatively high temperature degree injection molding (270－320T between ）, versus for material temperature adjustment scope/range relatively narrow, process property 不如PMMA. injection pressure for flow property effect/influence relatively small, viscosity large, still need relatively large injection pressure, versus is anti internal stress generate, holding pressure time need amount short. shrinkage rate large, dimensions stability, product internal stress large, easy cracking, therefore use improve/increase temperature degree is pressure improvement flow property, and from improve/increase mold temperature degree, improvement mold structure and rear decrease/reduce cracking can can. injection speed degree low 时, gate easy 生波纹 and other defect, 放射咀 temperature degree need mono control, mold temperature degree need high, runner, gate retardant force need small.

iii.PET process features

PET molding temperature degree high, material temperature adjustment scope/range narrow （260－300℃）, 但熔化 rear, flow property good, process property 差, 且往往 in in need add anti plant/unit. machine strong/high degree and property can injection rear high, must through tensile and modified can improvement property can. mold temperature degree control, is anti warpage. deformation important 回素, 回此建议 using/adopting hot runner mold. mold temperature degree high, 否则会引起 surface gloss and demolding difficult.

三, transparent plastics parts defect and solutions

1) 银纹: 由充模 and cold process in, internal stress toward property effect/influence, direction generate force, make resin flow upper orientation, and non flow orientation generate light rate different 而生闪 light filament 纹, its expand rear, can can make product cracks. remove in injection molding process and mold upper attention/notes outer, most good product as 退火处理. 如PC material can add hot to 160℃ above maintain 3－5 separation 钟, again cooling can.

2） bubbles: due to resin inner water gas and other gas 体排不出, or 因充模不足, cold surface also fast cold 凝而形 formed “ true 空泡”.

3） surface gloss 差: 主于 mold coarse degree large, 另一方面 cold 凝 早, make resin can mold surface 状态, has this make its surface micro small 凹凸不平, make product gloss.

4）震纹: is from gate is in  心形 formed 密集波纹, its causes melt viscosity large, front material already in type cold 凝, rear material also 冲破此 cold 凝面, make surface 出现震纹.

5）泛白,亮点: main/primary due to in gas in 灰尘落入 raw materials in or raw materials water amount large 而引起.

6）白烟, black spots: main/primary due to plastics in machine inner, local hot make machine resin generate separation understanding or 变质而形 formed.