Cov txheej txheem cov yam ntxwv ntawm PP

PP tau zoo fluidity ntawm melting kub thiab zoo molding kev kawm. PP muaj ob tug yam ntxwv hauv kev ua:

Ua ntej: Lub viscosity ntawm PP yaj poob qis dua nrog qhov nce ntawm shear tus nqi (tsawg dua cuam tshuam los ntawm qhov kub thiab txias);

Thib ob: Cov txheej txheem molecular yog siab thiab tus nqi shrinkage yog loj. Kev ntsuas kub ntawm PP yog 220 ~ 275℃Cov. Nws zoo dua tsis pub tshaj 275℃Cov. Nws muaj cov zoo thermal stability (kev txiav txim siab qhov kub yog 310)℃), tab sis nws nyob qis qis hauv cov thoob rau lub sijhawm ntev tom qab kub (270-300℃) Muaj peev xwm ua tau ntawm kev txo qis. Txij li thaum viscosity ntawm PP txo qis dua nrog qhov nce ntawm shear ceev, nce qhov kev txhaj tshuaj siab thiab txhaj tshuaj nrawm yuav txhim kho nws qhov kev npliag, txhim kho shrinkage deformation thiab kev nyuaj siab. Rau pwm kub (40 ~ 80℃), Nws raug nquahu kom siv 50℃.

Qhov ntsuas ntawm crystallization feem ntau yog txiav txim siab los ntawm pwm kub, thiab yuav tsum tswj nyob hauv thaj tsam li 30-50℃Cov. PP melt tuaj yeem dhau los ntawm qhov sib txawv txav pwm heev thiab tshwm sim cov ntug ntse. Nyob rau hauv cov txheej txheem yaj ntawm PP, nws yuav tsum nqus dej ntau qhov kub ntawm fusion (qhov kub tshwj xeeb yog qhov loj dua), thiab cov khoom yog kub tom qab tawm ntawm cov pwm.

PP khoom tsis tas yuav tsum tau ziab thaum lub sijhawm ua, PP shrinkage thiab crystallinity tsawg dua PE. Qhov kev txhaj tshuaj nrawm no feem ntau yog qhov siab txhaj tshuaj molding kom txo qis sab hauv. Yog tias muaj qhov tsis xws luag nyob rau saum npoo ntawm cov khoom, tom qab ntawd txhaj tshuaj nrawm qis ntawm qhov kub siab yuav tsum tau siv. Kev txhaj tshuaj siab: tuaj yeem txog 1800bar.

khiav thiab lub rooj vag: Rau cov neeg khiav dej txias, cov ua haujlwm khiav ntawm txoj kab uas hla yog 4 ~ 7 hli. Nws raug nquahu kom siv qhov chaw nres puag ncig txhaj tshuaj thiab cov channel ntws. Txhua hom rooj vag yuav siv tau. Cov rooj vag qhov taub dav xws li 1 ~ 1.5mm, tab sis lub rooj vag me li 0.7 hli kuj tseem siv tau. Rau ntug rooj vag, qhov tsawg kawg nkaus lub rooj vag qhov tob yuav tsum yog ib nrab ntawm phab ntsa tuab; qhov tsawg kawg nkaus lub rooj vag dav yuav tsum yog tsawg kawg ob zaug ntawm phab ntsa tuab, PP khoom siv tuaj yeem siv cov txheej txheem kub kub.

PP yeej ib txwm muaj cov khoom siv tseem ceeb rau kev tsim cov khoom siv, vim nws muaj peev xwm xim, hnav tsis kam, tshuaj tiv thaiv thiab kev lag luam muaj txiaj ntsig.