Shanghai Daoqin Plastics Co., Ltd.

        pbt is what material? PBT is what material, application in which field/area, how material property?
product type 别: molding material, engineering plastics, resin   
application industry: automotive 业; electrical 脑业; electrical appliances 业  
product applications: 供 electronics, electrical and automotive parts manufacturing textile use fiber  
product features: low 末端羧基 content, hydrolysis resistant property USA UL can excellent engineering plastics @ dimensions property 佳 @ resistant property and chemical resistant product property @ electrical property, machine property 均佳 @
 

PBT brief introduction
pbt is what material ? polybutylene terephthalate (PBT), 英文名polybutylece terephthalate（简称PBT）, belongs to polyester series, is 由1.4- butanediol (1.4-Butylene glycol) and for 苯二甲 acid (PTA) or for 苯二甲 acid ester (DMT) poly shrink combined formed, 并经由 mixing/compounding made formed white semi transparent to transparent, crystallization type thermoplastic polyester resin. and PET一起统称 is thermoplastic polyester, or saturated and polyester.

PBT历 history
PBT most is Germany 科学家P.Schlack于1942 year made formed, rear USA Celanese company （现 is Ticona）进行 industrial development, 并以Celanex商 product upper 市, 于1970 year 以30%玻璃纤 reinforcement plastics market, product is X-917, rear is CELANEX. 1971 year Eastman company launch has 玻璃纤 reinforcement and reinforcement product, product 名Tenite(PTMT); year GE company development type product, has reinforcement, reinforcement and self-extinguishing property product types. rear world 知名厂商 Germany BASF, Bayer, USA GE, Ticona, Japan Toray, Mitsubishi chemical, Taiwan new light combined 纤, long 春人造 resin, plastics and other company rear production 行列, full production 厂商共计三十余家.

PBT理化 features
PBT is white semi transparent to transparent, crystallization type thermoplastic polyester. tool has high heat resistant property, tough property, fatigue resistance, lubricated, low friction coefficient, weather resistance, water absorption low, is 0.1%, in wet ring in still maintain various material property （包括 electrical property can ）, electrical insulation property, 但体积 electrical retardant, dielectric loss large. heat resistant water, alkali type, acid type, type, easy 受卤化烃侵蚀, hydrolysis resistant property 差, low temperature lower can speed crystallization, molding property good. disadvantages is notched impact strength low, molding shrinkage large. large separation using/adopting glass fiber reinforcement or machine filling modified, its tensile strength, flexural strength can improve/increase above, heat deflection temperature (HDT) large improve/increase. can in 140℃ lower long as, glass fiber reinforced rear products 纵, toward shrinkage rate 不一致, easy make products warpage.
 
PBT processing process
PBT also can is thermoplastic polyester plastics, is suitable for different processing use, generally how much add additives, or and its it plastics mixed, 随 添 add material ratio/proportion different, can manufacturing different specifications product. due to PBT tool has heat resistant property, weather resistance, resistant product property, electrical features 佳, water property small, gloss good, widely used in electronics electrical appliances, automotive parts, machine 械, use product and other, 而PBT product also and PPE, PC, POM, PA and other is large use engineering plastics.
PBT crystallization speed degree fast, most processing methods is injection molding, other methods also has extrusion, blow molding, coating and various processing molding, molding front drying, water separation content need drop 至0.02%.
PBT injection molding process features and process parameters setting:
PBT polymerization process formed 熟, cost relatively low, molding processing easy. modified PBT property can 不佳, application need for PBT进行 modified, its in, glass fiber reinforcement modified grade 占PBT 70％ above.
 

1 PBT process features
PBT tool has obvious melting point, melting point is 225～235℃, is crystallization type material, crystallization degree can 达40％.
PBT melt viscosity temperature degree effect/influence 不如剪切应 force that large, therefore, in injection molding in, injection pressure for PBT melt flow property effect/influence is obvious.
PBT in melt lower flow property good, viscosity low, 仅次于 nylon, in molding easy 发生“流延” phenomenon.
PBT molding products toward property. PBT in high temperature lower water easy degradation.
2 injection molding machine
selection screw injection molding machine 时. 应考虑如 lower 几点.
① products use material amount control in injection molding machine most large injection amount 30％～80％. use large injection molding machine production small products.
②应 selection type screw, long ratio is 15～20, pressure shrink ratio is 2.5～3.0.
③应 selection 自锁式 nozzle, belt/tape has add hot temperature plant/unit.
④ in molding flame retardant grade PBT时, injection molding machine has parts anti 腐处理.
3 products and mold design
① products thick degree 不宜太 thick, PBT for very 敏感, therefore, products and other 渡处应 using/adopting 圆弧连接.
②未 modified PBT molding shrinkage relatively large, in 1.7％～2.3％, mold need has demolding degree.
③ mold need gas or gas 槽.
④ gate need large.
⑤ mold 需设置控 temperature plant/unit. mold most high temperature degree can ultra- 100℃.
⑥ flame retardant grade PBT molding, mold surface need 镀铬, anti 腐.
4 raw materials 准备
injection molding front need drying, need will water separation content control in 0.02％ below/following. using/adopting hot ring drying 时, temperature degree is 105℃, 120℃ or 140℃时, for time ultra- 6h, 4h, 2h. material thick degree low 于30mm.
5 injection molding process parameters
① injection temperature degree PBT separation understanding temperature degree is 280℃, therefore production in generally control in 235～245℃ between.
② injection pressure injection pressure generally is 50～100MPa.
③ injection speed rate PBT cooling speed degree fast, therefore need using/adopting relatively fast injection speed rate.
④ screw speed and back pressure molding PBT screw speed ultra- 80r/min, generally in 25～60r/min between. back pressure generally is injection pressure 10％～15％.
⑤ mold temperature degree generally control in 70～80℃, 各部位 temperature degree ultra- 10℃.
⑥ molding cycle generally lower is 15～60 s.
6 precautions
① recycled material use recycled material and new material ratio/proportion generally in 25％～75％.
② demolding agent use generally lower use demolding agent, necessary can using/adopting has machine silicon demolding agent.
③停 machine PBT machine time in 30min以 inner, can will temperature degree drop to 200℃时停 machine. long machine rear again production 时, need will material inner material 排空, again add new material can positive production.
④ products rear generally lower need 进行处理, necessary in 120℃时处理1～2h.

PBT price
also rise decline 吗? most price has decline trend, 客户买跌不买涨, more is use, 随 订 mono amount 并观望, PBT plastics rear 市究竟 how to 呢? expert short has can can, long is rise, 2015 year is in 两倍应该 is comparison can can.