Dab tsi yog cov laj thawj tseem ceeb uas cuam tshuam rau kev ua haujlwm ntawmpolyurethane?
1. Kev cuam tshuam ntawm cov feem pua ntawm cov prepomer isocyanate pawg (NCO): Raws li NCO nce, hardness, tsim kua muag kuj, ruaj tensile zog, thiab tensile zog nce, thiab viscosity ntawm lub polymer txo, uas yog ib qho yooj yim rau defoam. thiab sib tov, thiab elongation txo; Yog tias NCO siab dhau lawm, qhov kev kho ntawm cov roj hmab yog ceev heev, thiab lub neej hauv lub hwj yuav luv luv, uas yog qhov tsis zoo rau cov txheej txheem pouring.Yog li ntawd, NCO% feem ntau tsim nyog ntawm 2.4-6 .5%.
2. Influence ntawm chain expansion coefficient:
Qhov sib npaug sib npaug (NH2 / NCO) ntawm amine curing agent (MOCA) rau NCO hauv prepomer muaj qhov cuam tshuam loj rau lub cev ntawm cov roj hmab, feem ntau yog 0.85-0.95% yog qhov tsim nyog. Polyurethane feem ntau yuav tsum tswj hwm me ntsis ntawm NCO rau MOCA crosslinking systems, uas tuaj yeem ua rau cov khoom lag luam elastomer muaj qhov tsim nyog ntawm crosslinking. Thaum cov saw expansion coefficient yog 0.88, cov tshuaj crosslinking thiab lub cev crosslinking ncav cuag qhov zoo, thiab tag nrho cov kev ua tau zoo ntawm elastomer yog qhov zoo tshaj plaws; : Thaum nws nce mus txog 1 lossis ntau dua, vim yog cov nyhuv plasticizing ntawm MOCA, thiab qhov tsis muaj zog ntawm cov tshuaj crosslinking thiab hydrogen saw, lub zog yuav txo qis, thiab qhov deformation mus tas li yog qhov loj. expansion system feem ntau siv 0.85).
3. Qhov cuam tshuam ntawm kev sib xyaw kub: Vim muaj ntau hom prepromers thiab cov saw txuas ntxiv, cov txheej txheem txheej txheem (sib tov kub) kuj txawv. Qhov sib tov kub ua rau lub neej ntawm lub hwj thiab lub sij hawm gel shortened. Qhov sib tov kub yog qis dhau. Tsis pub cov saw hlau txuas ntxiv. Txawm hais tias nws yog qhov tsim nyog rau kev ua kom lub neej ntev ntawm lub hwj thiab txhim kho lub cev, nws tsis yooj yim rau defoam thiab sib xyaw ua ke (vim muaj viscosity ntau), nws yog qhov tsim nyog tias cov saw txuas ntxiv tsis ua rau hauv prepomer, xws li MOCA, 110-120 degree yog qhov tsim nyog.
4. Lub ntsiab tseem ceeb ntawm qhov hnyav molecular ntawm polyols ntawm kev ua haujlwm: qhov loj ntawm qhov hnyav molecular txiav txim siab qhov ntom ntawm cov yam ntxwv pawg hauv polyurethane elastomer: hom polyester nce nrog qhov hnyav molecular, nws lub cev muaj zog tuaj yeem txhim kho; thaum hom polyether nce nrog qhov hnyav molecular, nws txoj kev ua raws li kev txhim kho, thiab lub zog tensile thiab modulus yuav txo qis. Feem ntau, qhov hnyav molecular ntawm polyols yuav tsum tswj ntawm 1100-2200.