PTMEGs nrog ib tug dav MWD muaj feem ntau dua ntawm ob qho tib si qis-MW diol molecules thiab high-MW chains piv nrog nqaim MWD PPG polyols. Cov saw luv luv diol feem hauv PTMEG tuaj yeem dhau los ua ib feem ntawm ntu ntu ntu nyuaj yog li ua kom cov concentration ntawm cov theem nyuaj thiab ua kom cov modulus thiab hardness ntawm elastomer. Ib qho kev nce rau hauv cov theem nyuaj ua rau muaj kev txwv ntxiv ntawm kev txav mus los ntawm cov ntu mos, yog li txo tus nqi thiab qhov cuam tshuam ntawm qhov txias thiab kev ntxhov siab vim crystallization ntawm PTMEG. Kev siv PTMEG 1000 (vs. PTMEG 2000) yuav ua rau muaj feem ntau dua ntawm cov qes-MW diol hom uas ua rau cov ntu nyuaj thiab yog li muaj kev cuam tshuam ntau dua rau kev tawm tsam kev sib xyaw crystallization.
Qhov siab molecular hnyav feem cuam tshuam nrog ib qho dav MWD ua rau muaj kev nce ntxiv hauv cov resiliency thiab rebound zog thiab kev txhim kho nyob rau hauv theem sib cais nyob rau hauv lub PUR elastomer. Raws li, qhov sib ntxiv ntawm PTMEG mus rau PPG polyol txhim kho hardness, tensile zog thiab resiliency thiab rebound zog ntawm PUR elastomer txuam. Ntxiv ntawm PPG polyols rau hauv ib qho kev sib xyaw ua rau qis dua Durometer, softer polyurethane elastomers. PPG polyols ua rau lub dilution nyob rau hauv qis-MW diol feem ntawm PTMEG polyol nrog txo qis hauv qhov nyuaj-thaiv concentration.
Polyether Polyol Blends hauv Adhesive Applications
Qhov sib npaug ntawm tack, adhesion thiab cohesion rog yog cov ntsiab lus tseem ceeb hauv kev tsim cov nplaum. Hauv Pressure Sensitive Adhesives (PSAs), tack, shear zog thiab tev lub zog yog ntxiv tswj cov khoom. Thaum xaiv cov polyol ua hauj lwm thiab nyuaj block-soft block ratio yog siv nyob rau hauv optimizing lub nplaum cov khoom ntawm ib tug TPU, blending PTMEG nrog PPG polyols muab lwm qhov ntev rau kev tsim cov nplaum.
Cov hauv paus ntsiab lus uas tau teev tseg saum toj no pab coj cov kev xaiv ntawm polyol sib xyaw hauv kev ua kom zoo dua cov khoom nplaum uas yuav tsum tau ua. Rau cov laj thawj hais saum toj no, PTMEG, uas yog crystallizable, qhia ntau dua adhesion thiab cohesion yam ntxwv hauv PUR. PPG polyols txhim kho tack thiab adhesion rau hydrophobic nto thiab txhim kho tuav cov yam ntxwv zoo li viscosity. Hloov qhov piv ntawm PTMEG thiab PPG polyols hauv kev sib xyaw tso cai rau kev ua kom zoo ntawm cov nplaum nplaum kom tau raws li ntau yam kev ua tau zoo. Hauv ib txoj kev tshawb fawb, kev sib xyaw ua ke zoo heev ntawm tack, shear, thiab tev cov khoom tau txais hauv PSA ua los ntawm 50: 50 sib xyaw ntawm PTMEG thiab PPG polyols.2
Polyol Blends hauv Cast PUR Elastomers
Nyob rau hauv ib qho kev txhaj tshuaj cam khwb cia polyurethane elastomers, reactivity, thiab kho tus nqi / demold lub sij hawm nyob rau hauv ib tug polyol / MDI / BDO system yog sai npaum li cas nrog ib tug PTMEG polyol vs. a PPG polyol. Qhov no qhia txog 100% thawj hydroxy di-functionality hauv PTMEG. PPG polyols ua nrog cov pa KOH catalyst muaj 3-4 mole feem pua ntawm mono-hydroxy concentrations (lwm qhov terminus yog allyl unsaturation) thiab qis reactivity theem nrab hydroxyl functionality. Zoo tag nrho cov khoom elastomer kawg txhim kho nrog qhov sib ntxiv ntawm PTMEG hauv kev sib xyaw nrog PPG polyol. Qhov no suav nrog hardness, tensile thiab tsim kua muag zog, resiliency thiab rebound zog, puas, tensile thiab compression teeb. Muaj ntau yam cuam tshuam nrog cov kev txhim kho no: 1) tag nrho cov khoom zoo tshaj plaws ntawm cov qauv PTMEG linear, 2) kev ntxhov siab vim muaj crystallization ntawm qib siab ntawm PTMEG, 3) cov saw hlau tsawg kawg vim qhov siab 2.0 functionality ntawm PTMEG diol, thiab 4) nce nyob rau hauv tag nrho cov polymer MW ua tau. Rau cov laj thawj no, PPG polyols tsim los ntawm cov txheej txheem KOH feem ntau yog siv hauv cov ntawv thov polyurethane ua npuas ncauj thiab tsawg dua hauv cam khwb cia thiab TPU elastomers. Ob Chav Hlau Cyanide (DMC) catalysts tsim PPG polyols nrog kev ua haujlwm siab thiab cov ntsiab lus tsis tshua muaj mono-unsaturation. DMC catalysts yog siv rau siab MW thiab elastomer qib PPG polyols.
Cov kev tshawb fawb tau tshaj tawm tias tsawg li 10-20 qhov hnyav feem pua ntawm PPG polyol hauv PTMEG pib cuam tshuam rau kev ntxhov siab crystallization ntawm PTMEG polyols, nrog rau kev sib koom ua ke hauv qhov kawg elongations.3
Polyol Blends hauv TPUs thiab Prepolymer Cast Elastomers
Hauv prepolymers thiab TPUs, qhov qis viscosity ntawm PPG polyols tuaj yeem muab cov txiaj ntsig zoo. Hais txog cov khoom siv kho tshuab, tib cov qauv zoo li tau tham txog cam khwb cia elastomers siv rau prepolymer raws li tshuab thiab TPUs. Tag nrho qhov loj ntawm cov khoom sib txawv tuaj yeem txuas nrog kev sib xyaw ntawm PTMEG thiab PPG polyols hauv elastomeric polyurethanes.
Polyurethane Elastomer Summary
Kev sib xyaw ntawm PTMEG thiab PPG polyols tso cai rau kev ua kom zoo ntawm cov khoom thiab cov nqi hauv polyether polyurethane formulations. Ntxiv ntawm PTMEG rau PPG polyols txhim kho tensile, tsim kua muag thiab rebound / resilience zog, dynamic zog, thiab adhesion-cohesion hauv cov nplaum. PPG polyols tuaj yeem txhim kho tack, "txias-hardening" cov yam ntxwv, softness, thiab ua hauv PTMEG elastomers, thaum txo cov nqi raw khoom.
Cov khoom siv polyol no tuaj yeem tsim muaj txiaj ntsig hauv daim ntawv thov polyurethane xws li cov nplaum, cam khwb cia polyurethane elastomers, TPUs thiab polyurethane dispersion txheej.