Polyvinyl chloride (PVC) additives yog cov khoom siv tseem ceeb rau kev txhim kho cov khoom ua haujlwm thiab cov khoom zoo. Cov xwm txheej thiab kev ruaj ntseg ntawm lawv cov txheej txheem tsim khoom ncaj qha txiav txim siab purity, dispersibility, thiab kev ua tau zoo ntawm cov khoom. Tsis zoo li kev tsim cov PVC resin nws tus kheej, cov khoom siv ntxiv muaj ntau theem, suav nrog cov organic synthesis, compound dispersion, kev kho deg, thiab kev tswj kom zoo. Kev tswj cov txheej txheem nruj yuav tsum ua kom tiav kev tsim kho thiab kev sib xyaw ua ke ntawm cov khoom siv ua haujlwm kom tau raws li qhov yuav tsum tau ua ntawm ntau qhov chaw thov.
Raw khoom refining thiab pretreatment yog qhov pib ntawm cov txheej txheem. Nyob ntawm seb hom additives, cov khoom siv raw muaj xws li hlau oxides, fatty acids, aromatic compounds, polymer emulsions, thiab ntau yam kev ua haujlwm monomers. Cov khoom siv hlau yuav tsum tau calcined, pulverized, thiab sieved kom ntseeg tau tias cov khoom me me thiab ruaj khov. Organic acids thiab esters yuav tsum tau dehydrated, decolorized, thiab kuaj purity kom tsis txhob ya raws thiab impurities los ntawm kev cuam tshuam cov kev tshwm sim tom ntej los yog ua rau discoloration los yog nag lossis daus nyob rau hauv cov khoom tiav. Cov ntaub ntawv raw li kua yuav tsum tau lim thiab degassed los tiv thaiv npuas los ntawm kev ua tsis xws luag thaum lub sij hawm tom ntej dispersion los yog granulation. Lub hom phiaj tseem ceeb ntawm cov theem no yog nyob rau hauv cov ntaub ntawv raw khoom zoo thiab batch -rau -batch conformency tswj, nteg lub hauv paus txhim khu kev qha rau tom ntej synthesis los yog compounding.
Rau cov khoom siv hluavtaws, xws li hlau xab npum kub stabilizers lossis plasticizers nrog cov qauv tshwj xeeb, cov txheej txheem tseem ceeb yog cov organic synthesis. Cov txheej txheem ib txwm suav nrog kev npaj cov khoom xyaw, cua sov, tshuaj tiv thaiv catalytic, kho, thiab tom qab- kho. Kev tswj xyuas meej ntawm qhov kub, siab, pH, thiab nplawm tus nqi yog xav tau nyob rau hauv lub reactor los coj cov kev taw qhia tsim ntawm lub hom phiaj cov khoom thiab suppress sab kev xav. Piv txwv li, lub synthesis ntawm stearates yuav tsum tau nqa tawm nyob rau hauv ib tug inert cua los yog txo lub siab los tiv thaiv oxidation thiab discoloration; esterification cov tshuaj tiv thaiv ntawm plasticizers yuav tsum tau segmented kub tswj thiab raws sij hawm tshem tawm ntawm byproduct dej los txhim kho conversion tus nqi thiab xim stability. Tom qab cov tshuaj tiv thaiv, ib nrab- cov khoom tiav tau txais los ntawm centrifugation, ntxuav, ziab, los yog lub tshuab nqus tsev distillation, thiab cov cim tseem ceeb xws li melting point, acid nqi, thiab iodine nqi raug kuaj.
Compounding thiab dispersion yog cov kauj ruam tseem ceeb hauv kev npaj cov khoom siv ntxiv. Ob los yog ntau dua cov khoom siv ua haujlwm tau ntxiv rau qhov siab - sib tov sib xyaw los yog lub ntiaj teb sib xyaw ua ke raws li kev sib xyaw ua ke, thiab cov khoom siv hluav taws xob shearing thiab thermal cuam tshuam ua rau cov khoom ua raws li cov khoom thauj lossis sib cuam tshuam nrog ib leeg. Rau cov tshuab hmoov, feem ntau siv cov cua sov thiab sib tov. Ua ntej, qis- ceev premixing tiv thaiv hmoov ya, ua raws li siab- ceev shearing los txhawb kev tawg. Qhov kawg kub yog teem raws li lub thermosensitivity ntawm cov khoom kom tsis txhob muaj overheating thiab decomposition. Rau cov khoom ua kua los yog muab tshuaj txhuam, ua ntej -emulsification los yog masterbatch txoj kev yuav siv tau los npaj cov concentrated dispersions, uas yog ces proportionally ntxiv rau qhuav hmoov system los txhim kho uniformity thiab txo cov plua plav phom sij. Nyob rau theem no, nws yog ib qho tseem ceeb kom ua kom zoo dua qhov kev noj zaub mov thiab lub sijhawm sib xyaw, vim tias qhov sib txawv ntawm lub zog saum npoo ntawm cov khoom sib txawv tuaj yeem yooj yim ua rau agglomeration lossis cais.
Qee cov additives xav tau granulation los yog kev kho deg los txhim kho kev ua haujlwm thiab kev ua haujlwm. Cov txheej txheem granulation muaj xws li ntub granulation thiab qhuav spheroidization. Cov yav tas yuav sib tov hmoov nrog dej los yog ib tug binder los ua ib tug granular slurry, uas yog ces qhuav thiab sieved. Cov tom kawg siv cov tshuab dov rau agglomerate hmoov zoo rau hauv cov khoom tsis tu ncua, yooj yim rau kev ntsuas tsis siv neeg thiab kev xa khoom. Kev kho deg tuaj yeem siv microencapsulation lossis kev hloov pauv tus neeg sawv cev sib txuas. Piv txwv li, txheej tsis tshua muaj molecular hnyav plasticizers nrog polymers lossis inorganic oxides tuaj yeem txo cov kev tsiv teb tsaws chaw; kho inorganic fillers nrog silane coupling cov neeg ua haujlwm tuaj yeem txhim kho lawv cov kev sib raug zoo nrog PVC matrix.
Tom qab ua tiav, cov khoom tiav tau txias, sieving, homogenization, thiab ntim. Cov txheej txheem cua txias yuav tsum maj mam txhawm rau txhawm rau tiv thaiv kev ntxhov siab los ntawm kev ua rau cov khoom tawg lossis cov dej nag ntxiv. Sieving tshem tawm ultrafine los yog coarse hais, kom ntseeg tau tias cov khoom loj me me. Homogenization suav nrog kev cia rau qee lub sijhawm kom paub meej homogenization ntawm cov khoom siv. Kev ntim khoom siv cov dej noo- pov thawj, lub teeb- pov thawj, thiab cov khoom siv tiv thaiv- zoo li qub, thiab tau sau nrog cov lej batch thiab cov ntsuas kev ua tau zoo kom yooj yim traceability.
Kev tswj kom zoo yog siv thoob plaws hauv tag nrho cov txheej txheem. Cov ntsiab lus tseem ceeb tswj hwm (KCPs) tau teeb tsa los ntsuas cov khoom siv raw purity, cov tshuaj tiv thaiv kev hloov pauv, kev sib xyaw ua ke, qhov loj me me, thiab thermal stability. Cov txheej txheem tswj xyuas kev txheeb cais (SPC) yog siv los txheeb xyuas tam sim thiab kho qhov sib txawv. Rau cov khoom siv ntxiv siv rau hauv kev sib cuag zaub mov, kev kho mob, lossis cov khoom siv me nyuam yaus, txawm tias muaj kev txwv tsis pub muaj kev txwv thiab cov qauv kev nyab xeeb yuav tsum tau ua.
Zuag qhia tag nrho, cov txheej txheem tsim khoom ntawm polyvinyl chloride (PVC) additives yog ib qho kev ua tiav uas suav nrog cov khoom siv raw refining, organic synthesis, compounding thiab dispersion, granulation, thiab kev ruaj ntseg zoo. Kev sib koom ua ke zoo thiab kev tswj hwm nruj ntawm txhua theem kom ntseeg tau tias cov khoom lag luam tuaj yeem ua haujlwm ruaj khov ntawm cov cua sov, plasticization, kev hloov kho thiab kev ua haujlwm hauv PVC, muab cov khoom siv hauv paus rau kev txhim kho cov khoom siv PVC thiab nthuav lawv daim ntawv thov.