Polyethylene (PE)
1. Kev ua tau zoo ntawm PE
PE yog cov yas uas tsim tawm ntau tshaj plaws ntawm cov yas, nrog rau qhov ceev ntawm li 0.94g / cm3. Nws yog tus cwj pwm los ntawm kev pom tseeb, mos, tsis muaj tshuaj lom, pheej yig, thiab yooj yim rau kev ua. PE yog ib qho polymer crystalline ib txwm muaj thiab muaj qhov tshwm sim tom qab shrinkage. Muaj ntau hom ntawm nws, cov feem ntau siv yog LDPE uas yog mos dua (feem ntau hu ua roj hmab mos lossis paj ntaub), HDPE uas feem ntau hu ua roj hmab mos tawv, uas yog tawv dua LDPE, muaj kev xa hluav taws xob tsis zoo thiab crystallinity siab; LLDPE muaj kev ua tau zoo heev, zoo ib yam li cov yas engineering. PE muaj kev tiv thaiv tshuaj zoo, tsis yooj yim rau corrode, thiab nyuaj rau luam tawm. Qhov chaw yuav tsum tau oxidized ua ntej luam tawm.
2. Kev siv PER
HDPE: ntim cov hnab yas, cov khoom siv niaj hnub, cov thoob, cov xov hlau, cov khoom ua si, cov ntaub ntawv tsim kho, cov thawv
LDPE: ntim cov hnab yas, paj yas, cov khoom ua si, cov xov hlau siab, cov ntawv sau, thiab lwm yam.
3. Cov yam ntxwv ntawm cov txheej txheem PE
Qhov tshwj xeeb tshaj plaws ntawm PE qhov chaw yog tias lawv muaj qhov loj molding shrinkage tus nqi thiab yooj yim shrinkage thiab deformation. PE cov ntaub ntawv muaj dej tsawg nqus thiab tsis tas yuav ziab. PE muaj ntau yam kub ua tiav thiab tsis yooj yim rau decompose (qhov kub decomposition yog li 300 ° C). Qhov kub ua tiav yog 180 txog 220 ° C. Yog tias lub siab txhaj tshuaj siab, cov khoom ceev yuav siab thiab qhov shrinkage tus nqi yuav me me. PE muaj qhov nruab nrab fluidity, yog li lub sijhawm tuav yuav tsum ntev dua thiab pwm kub yuav tsum khaws cia tas li (40-70 ° C).
Qhov degree ntawm crystallization ntawm PE muaj feem cuam tshuam rau cov txheej txheem molding. Nws muaj qhov kub siab dua rau kev khov kho. Qhov kub ntawm pwm qis dua, qhov crystallinity qis dua. . Thaum lub sijhawm crystallization, vim yog qhov anisotropy ntawm shrinkage, kev ntxhov siab sab hauv tshwm sim, thiab PE qhov chaw yooj yim rau deform thiab tawg. Muab cov khoom tso rau hauv dej da dej hauv 80 ℃ dej kub tuaj yeem txo qhov kev ntxhov siab sab hauv mus rau qee qhov. Thaum lub sijhawm molding, qhov kub ntawm cov khoom yuav tsum siab dua qhov kub ntawm pwm. Lub siab txhaj tshuaj yuav tsum qis li sai tau thaum ua kom ntseeg tau qhov zoo ntawm qhov. Qhov txias ntawm pwm yog qhov tshwj xeeb tshaj yog xav tau kom sai thiab sib npaug, thiab cov khoom yuav tsum kub thaum demolded.
Polypropylene (PP)
1. Kev ua tau zoo ntawm PP
PP yog ib qho crystalline polymer nrog qhov ceev ntawm tsuas yog 0.91g / cm3 (tsawg dua dej). PP yog lub teeb tshaj plaws ntawm cov yas siv feem ntau. Ntawm cov yas dav dav, PP muaj qhov tiv taus cua sov zoo tshaj plaws, nrog rau qhov kub hloov pauv cua sov ntawm 80 txog 100 ° C thiab tuaj yeem ua kom npau hauv dej npau. PP muaj kev tiv thaiv kev ntxhov siab zoo thiab lub neej khoov siab, thiab feem ntau hu ua "100% yas".
Qhov ua tau zoo ntawm PP zoo dua li cov khoom siv PE. Cov khoom PP yog lub teeb yuag, tawv thiab tiv taus tshuaj lom neeg. Qhov tsis zoo ntawm PP: qhov tseeb ntawm qhov ntev tsis zoo, tsis muaj zog txaus, tsis tiv taus huab cua, yooj yim tsim "kev puas tsuaj los ntawm tooj liab", nws muaj qhov tshwm sim tom qab ntsws, thiab cov khoom yooj yim laus, ua rau tawg thiab deformed.
2. Daim ntawv thov ntawm PP
Ntau yam khoom siv hauv tsev, lub hau lauj kaub pob tshab, cov kav xa tshuaj, cov thawv tshuaj, cov khoom siv kho mob, cov ntawv sau, cov khoom ua si, cov xov hlau, cov khob dej, cov thawv tig rov qab, cov kav dej, cov pob qhov rooj, thiab lwm yam.
3. Cov yam ntxwv ntawm PP:
PP muaj cov kua dej zoo ntawm qhov kub yaj thiab kev ua tau zoo molding. PP muaj ob yam ntxwv:
Ua ntej: qhov viscosity ntawm PP yaj txo qis nrog rau qhov nce ntawm shear rate (tsawg dua cuam tshuam los ntawm qhov kub);
Qhov thib ob: Qhov degree ntawm molecular orientation siab thiab qhov shrinkage tus nqi loj.
Qhov kub ua tiav ntawm PP zoo dua nyob ib puag ncig 200 ~ 250 ℃. Nws muaj kev ruaj khov thermal zoo (qhov kub decomposition yog 310 ℃), tab sis ntawm qhov kub siab (280 ~ 300 ℃), nws yuav lwj yog tias nws nyob hauv lub thoob ntev. Vim tias qhov viscosity ntawm PP txo qis ntau nrog rau qhov nce ntawm shear rate, kev nce qhov siab txhaj tshuaj thiab qhov ceev txhaj tshuaj yuav txhim kho nws cov fluidity; txhawm rau txhim kho shrinkage deformation thiab dents, qhov kub pwm yuav tsum tau tswj hwm hauv qhov ntau ntawm 35 txog 65 ° C. Qhov kub crystallization yog 120 ~ 125 ℃. PP yaj tuaj yeem hla dhau qhov sib txawv pwm nqaim heev thiab tsim ib ntug ntse. Thaum lub sijhawm yaj, PP yuav tsum nqus tau ntau qhov kub yaj (qhov kub tshwj xeeb loj dua), thiab cov khoom yuav kub heev tom qab tawm ntawm pwm. Cov ntaub ntawv PP tsis tas yuav qhuav thaum lub sijhawm ua tiav, thiab qhov shrinkage thiab crystallinity ntawm PP qis dua li PE.
Lub sijhawm tshaj tawm: Lub Kaum Ob Hlis-28-2023
