Stabilizer yog ib qho tseem ceeb ntawm cov koom ua haujlwm yas. Stabilizer synchronized nrog lub hnub yug thiab kev loj hlob ntawm PVC cob. Stabilizer Nws yog tsuas yog siv rau hauv cov khoom ntawm PVC cob. Yog li, qhov kev faib ua feem ntawm stabilizer thiab PVC cob thiab PVC hauv cov khoom muag thiab muag khoom yog zoo ib yam. PVC stabilizer siv tsawg tus lej, tab sis nws lub luag hauj lwm yog loj loj. Hauv PVC siv cov stabilizers tuaj yeem ua kom paub tias PVC tsis yooj yim rau degradation, ruaj khov dua. PVC ua feem ntau siv cov stabilizers yog cov hlau lead ntsev ruaj ruaj, cov xuab zeb hlau ruaj ruaj, cov chaw ruaj ntseg stabilizer, lub ntiaj teb tsis tshua muaj stabilizer, epoxy compounds thiab lwm yam. PVC degradation mechanism yog complex, lub mechanism ntawm txawv stabilizers tsis zoo li qub, cov nyhuv stability tseem txawv.
Kub polyvinyl chloride yog pom tias yog ib qho ntawm ntau hom polymers vim kev sib haum xeeb nrog ntau lwm yam ntaub ntawv xws li cov yas yas, cov ntsaws fill thiab lwm yam polymers. Stabilizer Lub lag luam tseem ceeb yog lub pluag thermal stability. Kev siv cov additives tuaj yeem hloov qhov muag pom kev thiab kev ua haujlwm ntawm cov roj (polyvinyl chloride) (PVC), tab sis tsis tiv thaiv lub lwj ntawm cov polymer. Txawm tias cov khoom siv lub cev (xws li cua sov, hluav taws xob) thiab cov tshuaj (oxygen, ozone) yuav ua rau cov khoom hnyav muab tua pov tseg, tab sis hu ua stabilizer ntawm ib hom tshuaj muaj peev xwm tiv thaiv tau, txo los yog txwv tsis pub cov khoom . PVC nyob rau 100 ~ 150 ℃ decomposition, ultraviolet light, Stabilizer mechanical zog, oxygen, ozone, hydrogen chloride thiab ib co nquag hlau ntsev thiab hlau oxides, thiab lwm yam. Yuav zoo heev lej lub decomposition ntawm PVC. PVC thermal oxygen kev laus yog ntau txoj, ib co ntaub ntawv qhia txog PVC thermal degradation txheej txheem muab faib ua ob kauj ruam.
(A) dehydrochlorination: PVC polymer molecular saw nyob rau qhov kev tshem tawm ntawm cov roj ntsha chlorine rau tsim hydrogen chloride, thaum tsim cov conjugated polyene;
(B) kev tsim ntawm chains ntev ntawm polyolefins thiab aromatic rings: Raws li qhov degradation progresses ntxiv, chlorine atoms ntawm cov allyl pawg tsis tshua ruaj khov thiab yooj yim tshem tawm los ua ntev chain conjugated polyenes, qhov sib "Sweeper hom" dehydrogenation, thaum ib tug me me ntawm cov nyiaj tawg CC, Stabilizer cyclization, ua rau muaj me me ntawm cov kab mob uas muaj ntxhiab. Lub decomposition ntawm dehydrochlorination yog lub ntsiab ua rau PVC kev laus. Nyob rau PVC degradation mechanism yog ntau txoj, yog tsis muaj teeb meem xaus, cov soj ntsuam ntawm npaj lub ntsiab dawb radical mechanism, ion mechanism thiab ib qho molecular mechanism.
Nyob rau hauv tus txheej txheem ntawm kev ua, lub thermal decomposition ntawm PVC rau lwm yam khoom hloov me ntsis, mas rau cov khoom tiav xim, muab stabilizer tau inhibit thawj xim ntawm cov khoom. Thaum muab cov HCl luaj tawm tuaj txog 0.1%, cov xim ntawm PVC pib hloov. Nyob ntawm seb muaj pes tsawg tus bonds uas tsim ua ob leeg, PVC yuav muaj xim txawv (daj, txiv kab ntxwv, liab, xim av, thiab dub). Yog hais tias muaj oxygen nyob rau hauv lub thermal decomposition ntawm PVC, ces yuav muaj colloidal carbon, peroxide, carbonyl thiab ester compounds. Txawm li cas los xij, thaum lub sij hawm ntev ntawm kev siv cov khoom, lub thermal degradation ntawm PVC muaj ib lub zog zoo rau cov khoom ntawm cov khoom. Ntxiv cov stabilizers tuaj yeem ncua qhov degradation ntawm PVC lossis txo cov teeb meem ntawm PVC degradation.
Hauv kev ua ntawm PVC ua los ntawm ntxiv cov stabilizers tuaj yeem tiv thaiv qhov degradation ntawm PVC, ces lub luag hauj lwm tseem ceeb ntawm cov stabilizers ua si: los hloov qhov tsis muaj zog cov tshuaj atoms, Stabilizer hydrogen chloride absorption, thiab unsaturated qhov chaw ntawm cov tshuaj tiv thaiv ntxiv rau inhibit PVC molecules Ntawm degradation.
Lub tswv yim zoo tshaj plaws yuav tsum muaj ntau yam hauj lwm:
(1) hloov ib qho chaw nyob ruaj khov, tsis ruaj tsis khov, xws li chlorine atom los yog allyl chloride nrog ib tug tertiary carbon atom, los tsim ua ib qho kev ruaj khov;
(2) kom nqus thiab tshem tawm cov txheej txheem ntawm PVC uas tau tso tawm hauv HCS, Stabilizer kom tshem tawm cov kev hloov degradation ntawm HCl;
(3) tsis muaj kev cuam tshuam los yog siv cov hlau ions thiab lwm yam kev xiam oob qhab uas ua kom muaj kev ntxhov siab;
(4) los ntawm ntau hom tshuaj tiv thaiv kab mob tuaj yeem cuam tshuam kev loj hlob ntawm cov khoom tsis tau tso cai, tsis pub ntxig cov xim;
(5) qhov zoo tshaj plaws tiv thaiv tawm tsam ultraviolet lub teeb shielding.
PVC stabilizers feem ntau yog cov tsis muaj dej los sis cov keeb nruab nrog cev, thiab lub sij hawm nws tus kheej txhais tau hais tias muaj cov cations, los yog cov organic compounds, Stabilizer uas feem ntau cais los ntawm hoob kawm tshuaj. Feem ntau, cov cheebtsam hauv cov organic thiab cov organic sib xyaw yog (los yog loj) cov stabilizers, thaum lub tebchaw organic yog cov secondary lossis pabcuam ntxiv.
Stabilizers yog muab faib raws li tin, lead thiab ntshav Ib tsev neeg hlau xws li barium, tooj liab thiab zinc.
Tin stabilizer: muaj ib los yog ob lub txiaj ntsig cov kab mob, qhov seem ntawm cov pa oxygen los sis cov tshuaj sulfur uas muaj cov kab mob tetravalent tin tebchaw, PVC yog qhov zoo tshaj plaws stabilizer. Cov tebchaw no yog cov khoom ntawm organotin oxide losyog cov tshuaj hu ua organotin chloride nrog cov tshuaj tivthaiv ntawm cov tshuaj uas tsim nyog lossis ester.
Stabilizer synergistic mixtures muaj ntau thiab feem ntau muaj xws li ntau yam khoom xyaw nrog cov khoom cog thiab cov kabmob uas muaj zog (xws li cov zinc tshuaj, phosphite, epoxide, glyceride, UV absorbers, Agent thiab hais txog. Nws yog tseeb tias feem ntau ntawm cov synergistic compositions yog ib qho thiab tseem tsis tau pom muaj ib qho dav dav.
Organotin stabilizers yog cais rau hauv leej faj thiab leej faj dawb. Sulfur stabilizers zoo heev nyob rau hauv tag nrho cov khoom ruaj khov, tab sis muaj teeb meem nrog tastes thiab kev sib txuas uas zoo ib yam li cov leej faj-muaj sib txuas. Cov roj hnyav-uas muaj anions yog:
Ua txhaum - SR
Mercapto ester - S (CH) nCOOR
Mercapto ester - S (CH) nOCO
Los yog lub noob mis.
Cov tshuaj tsis muaj hnoos qeev yog raws li txiv neej acid los yog txiv roj acid esters, non-sulfur organotin yog cov tsis tshua zoo heev, tab sis nws muaj kev ruaj ntseg zoo.
Lead stabilizers: Cov kab mob ua kom muaj cov kab mob muaj xws li cov nram qab no: cov kua qab ntsev ntawm cov dihydroxy cov kua ntsev, hydrazine ntsev ntawm trihydrochloride, cov kua qab ntsev ntawm diacyl phthalate, lead
Raws li tus stabilizer, cov hmoov txhuas tsis ua kom tsis zoo rau cov khoom hluav taws xob zoo, tsis muaj dej txaus thiab sab nraum zoov huab cua tsis kam ntawm PVC khoom. Txawm li cas los xij, cov hlau nplaum ruaj ntseg muaj teeb meem, xws li tshuaj lom; cross-contamination, tshwj xeeb tshaj yog khaub lig-contamination nrog sulfur; tiam ntawm cov hmoov txhuas lead chloride, Stabilizer tsim ntawm kab txaij ntawm cov khoom tiav; ntau dua qhov hnyav, ua rau lub cev nyhav / ntim tsis txaus. Cov yeeb ncuab feem ntau ua rau PVC khoom ua opaque thiab hloov xim sai sai tom qab cua sov.
Txawm tias muaj kev tsis zoo thiab cov kev tsis zoo, cov stabilizers no tseem siv tau. Kev tiv thaiv hluav taws xob, cov hlau lead yog cov PVC stabilizer. Raws li cov nyhuv ua ke ntawm tus stabilizer no, muaj ntau yam yoog thiab tsis yeem, homopolymer thiab copolymer formulations uas tuaj yeem ua tiav.
Mixed metal stabilizers: Mixed metal stabilizers yog aggregates ntawm ntau lub tebchaw, feem ntau yog tsim rau cov kev siv PVC thiab cov neeg siv. Cov stabilizers no tau tsim los ntawm kev ntxiv rau barium succinate thiab cadmium citrate rau ntxiv ntawm barium xab npum, tshuaj xub npum tshuaj zinc, zinc xab npum, organic phosphites, antioxidants, solvents, extenders, Colorants, UV absorbers, ci ntsa iab, viscosity tswj cov neeg ua hauj lawm, lubricants, tackifiers , thiab khoom noj khoom haus zoo nkauj. Nyob rau hauv no txoj kev, muaj ntau heev ntau yam uas yuav cuam tshuam rau cov nyhuv ntawm qhov kawg stabilizer.
Group II hlau stabilizers xws li barium, calcium thiab magnesium tsis tiv thaiv cov xim thaum ntxov tab sis muab lub sij hawm zoo rau cov PVC ntev. Steady PVC nyob rau hauv no txoj kev pib nrog daj / txiv kab ntxwv, thiab ces tseem rau cua sov, maj ua txheeb / xim av, thiab thaum kawg dub.
Cadmium thiab zinc tebchaw yog thawj zaug siv los ua stabilizers vim tias lawv yog cov pob tshab thiab tuaj yeem khaws xim ntawm PVC khoom. Lub sij hawm ntev thermal stability los ntawm cadmium thiab zinc yog ntau me dua li ntawm barium compounds. Lawv feem ntau nyob rau hauv ib qho me me precursor los yog tsis muaj cov ntaub ntawv aura, Stabilizer qhov kev ua tiav qhov degradation.
Ntxiv nrog rau qhov kev faib ua feem ntawm cov hlau, cov nyhuv ntawm barium-steel stabilizer kuj yog hais txog nws cov khoom muaj nqis. Stabilizer Anions yog lub hauv paus tseem ceeb uas cuam tshuam rau cov nram qab no cov cuab yeej: lubricity, kev tsiv teb, transparency, pigment xim hloov, thiab thermal stability ntawm PVC. Cov nram qab no yog cov uas muaj ntau hom tshuaj sib xyaw hlau: 2-ethylhexanoate, phenate, benzoate, stearate
Nrog rau kev tsim cov tshuab ua thiab siv cov calcium-zinc stabilizer tau tsim. Thaum xub thawj, tag nrho cov khoom noj khoom haus ntawm PVC tau muab tso rau hauv tsoom fwv siv tshuaj calcium tshuaj, xab npum zinc. Yuav kom ua tau raws li cov kev xav tau ntawm cov neeg tau txais kev pab thiab kev tsim cov lag luam muaj peev xwm, tsim los ntawm kev siv ntawm no tsis tshua muaj txiaj ntsim ruaj khov ntawm PVC mis thiab khoom tsim khoom siv. Cov neeg pab txhawb nqa yuav siv tau nrog cov xab npum. Dihydropyridine thiab diketone yog cov kws pabcuam tshiab.