Roj hmab yog cov khoom siv polymer uas muaj zog heev nrog rov qab deformation, elastic ntawm chav tsev kub, tuaj yeem tsim deformation loj nyob rau hauv qhov kev txiav txim ntawm ib qho me me sab nraud quab yuam, thiab tuaj yeem rov qab mus rau nws qhov qub qub tom qab tshem tawm cov quab yuam sab nraud. Roj hmab belongs rau tag nrho amorphous polymer, nws cov iav hloov pauv kub (T g) yog qhov tsawg, qhov hnyav molecular feem ntau loj, ntau tshaj li ntau pua txhiab. Cov khoom siv roj hmab tau siv dav hauv txhua yam ntawm kev lag luam lossis lub neej.
Xyoo 1770, tus kws tshuaj lus Askiv J. Priestley tau tshawb pom tias roj hmab tuaj yeem siv los tshem tawm cov cwj mem sau. Thaum lub sij hawm, cov khoom siv rau lub hom phiaj no hu ua roj hmab, thiab lo lus tau siv txij li thaum.
Ua ntej, qhov chaw ntawm cov roj hmab
Roj hmab tau muab faib ua cov roj hmab ntuj thiab hluavtaws roj hmab ob yam.
Cov roj hmab ntuj yog tsim los ntawm cov pos hniav muab rho tawm los ntawm tsob ntoo roj hmab, roj hmab nyom thiab lwm yam nroj tsuag.
Synthetic roj hmab yog tau los ntawm polymerization ntawm ntau yam monomers.
Lub hauv paus tseem ceeb ntawm cov roj hmab ntuj yog tsob ntoo roj hmab peb-nplooj, uas yog thawj zaug loj hlob hauv South America, tab sis tom qab kev hloov pauv, cov ntoo roj hmab ntau kuj tau loj hlob nyob rau sab hnub tuaj Asia. Qhov tseeb, Asia tau dhau los ua qhov tseem ceeb tshaj plaws ntawm cov roj hmab. Thaum daim tawv nqaij ntawm tsob ntoo roj hmab no raug txiav, nws yuav raug mob (xws li cov tawv ntoo ntawm qia raug txiav) thaum nws zais cov kua txiv hmab txiv ntoo dawb uas muaj cov roj hmab emulsion, hu ua latex, latex tom qab condensation, ntxuav, molding, ziab kom tau. ntuj roj hmab.
Roj hmab ua los ntawm cov pos hniav guile txo rhiab heev. Tsis tas li ntawd, FIG ntoo thiab qee cov nroj tsuag hauv tsev neeg Euphorbia kuj muab roj hmab.
Lub teb chaws Yelemees tau sim kom tau cov roj hmab los ntawm cov nroj tsuag no thaum nws cov khoom raug txiav tawm thaum Ntiaj Teb Tsov Rog II, tab sis tom qab ntawd hloov mus ua cov roj hmab hluavtaws.
Cov roj hmab hluavtaws yog tsim los ntawm cov txheej txheem hluavtaws, siv cov khoom sib txawv (monomers) tuaj yeem ua ke rau hauv ntau hom roj hmab. Hauv 1900-1910, tus kws tshuaj CD Harris tau txiav txim siab tias cov qauv ntawm cov roj hmab ntuj yog cov polymer ntawm isoprene, uas qhib txoj hauv kev rau cov roj hmab hluavtaws. Nyob rau hauv 1910, Lavxias teb sab chemist SV Lebedev (Lebedev, 1874-1934) siv metallic sodium raws li pib rau polymerize 1, 3-butadiene rau hauv sodium butadiene roj hmab. Tom qab ntawd, muaj ntau hom roj hmab hluavtaws tshiab, xws li roj hmab butadiene, roj hmab neoprene, styrene butadiene roj hmab thiab lwm yam.
Kev tsim cov roj hmab hluavtaws tau zoo heev tshaj ntawm cov roj hmab ntuj, cov roj hmab styrene butadiene yog qhov loj tshaj plaws.
Roj hmab yog cov khoom siv raw khoom ntawm kev lag luam roj hmab, dav siv hauv kev tsim cov log tsheb, hose, daim kab xev, cables thiab lwm yam khoom siv roj hmab
Ob, muaj pes tsawg leeg ntawm roj hmab
Cov roj hmab ntuj yog tsim los ntawm latex, thiab qee yam ntawm cov khoom siv tsis yog roj hmab uas muaj nyob rau hauv latex tseem nyob hauv cov khoom siv roj hmab. Cov roj hmab dav dav muaj 92-95 feem pua roj hmab hydrocarbon, tsis yog roj hmab hydrocarbon nyiaj rau 5 feem pua -8 feem pua . Vim yog cov txheej txheem tsim khoom sib txawv, qhov chaw sib txawv ntawm lub hauv paus chiv keeb thiab lub caij sib txawv, qhov kev faib ua feem ntawm cov khoom xyaw no yuav txawv, tab sis qhov tseem ceeb nyob rau hauv qhov chaw.
Protein tuaj yeem txhawb cov roj hmab vulcanization, ncua kev laus. Ntawm qhov tod tes, cov protein muaj zog nqus dej, tuaj yeem ua rau roj hmab noo noo nqus pwm, rwb thaiv tsev poob qis, cov protein kuj ua rau qhov tsis zoo ntawm cov cua sov.
Acetone extract yog ib tug xov tooj ntawm fatty acids thiab sterols ntau dua, ib co ntawm cov uas ua lub luag hauj lwm ntawm ntuj antioxidant thiab accelerator, thiab ib co yuav pab tau cov hmoov complex disperse nyob rau hauv lub mixing txheej txheem thiab ua si lub luag hauj lwm softening ntawm cov pos hniav nyoos.
Tshauv feem ntau muaj cov ntsev xws li magnesium phosphate thiab calcium phosphate, thiab cov hlau me me xws li tooj liab, manganese thiab hlau. Vim tias cov hlau ions sib txawv no tuaj yeem txhawb cov roj hmab aging, lawv cov ntsiab lus yuav tsum tau tswj.
Cov dej noo hauv cov kua nplaum qhuav tsis yog ntau tshaj 1 feem pua, uas tuaj yeem hloov pauv hauv cov txheej txheem ntawm kev ua haujlwm. Txawm li cas los xij, thaum cov dej noo ntau dhau, nws yuav tsis tsuas yog ua rau cov kua nplaum nyoos yooj yim rau pwm hauv cov txheej txheem cia, tab sis kuj cuam tshuam rau kev ua cov roj hmab, xws li kev sib xyaw ua ke yog ib qho yooj yim rau pawg; Calendering, extrusion txheej txheem yog ib qho yooj yim los tsim npuas, vulcanization txheej txheem ua npuas los yog spongy.
Kev sib xyaw ntawm cov roj hmab hluavtaws: Cov roj hmab hluavtaws yog cov polymer ua los ntawm cov roj av thiab cov nkev, nrog diolefin thiab olefin ua monomers.
Peb, cov qauv ntawm cov roj hmab
Linear qauv: Cov qauv ntawm cov roj hmab unvulcanized. Vim qhov hnyav molecular loj, tsis muaj zog sab nraud, macromolecular chains tshwm random coil nkhaus pawg. Thaum cov quab yuam sab nraud ua thiab tshem tawm cov rog, qhov kev cuam tshuam ntawm cov pab pawg xaim hloov pauv, cov saw hlau molecular rebounds thiab muaj lub zog zoo rov qab los, uas yog lub hauv paus ntawm cov roj hmab siab elasticity.
Ceg qauv: Aggregation ntawm branched chains ntawm roj hmab macromolecular chains los ua gels. Gel tsis zoo rau cov khoom siv roj hmab thiab kev ua haujlwm. Nyob rau hauv tus txheej txheem ntawm kev sib tov, ntau cov tebchaw feem ntau tsis tuaj yeem nkag mus rau hauv cheeb tsam gel, tsim hauv zos dawb paug, tsim kev txhawb zog thiab crosslinking, ua qhov tsis muaj zog ntawm cov khoom.
Crosslinked qauv: Linear molecules txuas rau ib leeg los ntawm kev sib txuas ntawm cov atoms lossis pawg ntawm cov atoms, tsim cov qauv peb sab. Cov qauv muaj zog ntxiv thaum cov txheej txheem kho tau zoo zuj zus. Nyob rau hauv txoj kev no, kev txav dawb ntawm cov saw ntu txo qis, cov yas thiab elongation txo qis, lub zog, elasticity thiab hardness nce, compression tas li deformation thiab o degree txo.
Kev cuam tshuam ntawm cov qauv roj hmab
Kev cuam tshuam ntawm cov roj hmab reinforcing zog yog tsom rau lub zog tensile thiab tearing lub zog. Txoj cai dav dav yog raws li hauv qab no: thaum lub particle loj yog tib yam, qhov kev txhawb zog ntawm cov qauv siab carbon dub ntawm cov roj hmab tsis-crystalline zoo heev, thiab feem ntau muaj zog tensile ntau dua thiab lub zog tearing. Cov qauv roj hmab kuj yog qhov tseem ceeb tshaj plaws uas cuam tshuam rau cov khoom siv hluav taws xob. Cov qauv saw-dendritic yog ib qho yooj yim los tsim ib txoj hauv kev sib txuas hauv cov roj hmab, uas yuav txhim kho cov khoom siv hluav taws xob. Cov saw hlau molecular ntawm cov roj hmab tuaj yeem ua crosslinked. Thaum cov roj hmab yog deformed los ntawm sab nraud quab yuam tom qab crosslinked, nws muaj peev xwm rov qab tau sai thiab muaj lub cev zoo thiab txhua yam khoom thiab tshuaj stability.
Plaub, cov yam ntxwv ntawm cov roj hmab
1. Thaum cov khoom siv roj hmab tau tsim, tom qab lub siab loj compression, vim qhov cohesion ntawm elastomer tsis tuaj yeem raug tshem tawm, thaum tsim pwm, feem ntau tsim cov shrinkage tsis ruaj tsis khov (lub shrinkage tus nqi ntawm cov roj hmab, vim yog cov roj hmab sib txawv thiab sib txawv) , yuav tsum yog tom qab ib lub sij hawm ntawm lub sij hawm, nyob rau hauv thiaj li yuav ua siab mos thiab ruaj khov. Yog li ntawd, thaum pib ntawm kev tsim cov khoom siv roj hmab, tsis hais cov mis los yog pwm, nws yog ib qho tsim nyog yuav tsum ua tib zoo xam thiab koom tes, yog tias tsis yog, nws yog ib qho yooj yim los tsim cov khoom loj tsis ruaj khov, ua rau cov khoom lag luam poob qis.
2 roj hmab yog kub-soluble thermosetting elastomer, vim yog sulfide hom ntawm lub cev tseem ceeb sib txawv, nws txoj kev kho qhov kub thiab txias, kuj tseem muaj qhov sib txawv, txawm tias vim muaj kev hloov pauv huab cua, qhov kub thiab txias hauv tsev. Yog li ntawd, cov txheej txheem tsim khoom ntawm cov khoom siv roj hmab yuav tsum tau hloov kho me ntsis txhua lub sijhawm. Yog tias tsis yog, nws yuav tsim qhov sib txawv ntawm cov khoom zoo.
3 Cov khoom siv roj hmab yog ua los ntawm cov khoom siv roj hmab tom qab cov roj hmab sib xyaw ua cov khoom siv raw, hauv cov khoom siv roj hmab raws li tus yam ntxwv ntawm tus qauv tsim, thiab teeb tsa cov khoom yuav tsum tau ua kom tawv. Cov khoom yog molded los ntawm roj hmab vulcanizing tshuab. Tom qab molding, cov khoom yog thaum kawg kho nrog ya ntug kom cov nto ntawm cov khoom du thiab burr dawb.
4 Cov khoom lag luam roj hmab kev laus yog nyob rau hauv qeb ntawm kev kuaj kev laus, roj hmab kev laus hais txog cov roj hmab thiab cov khoom siv hauv cov txheej txheem ntawm kev ua, cia thiab siv, vim muaj cov txiaj ntsig zoo ntawm sab hauv thiab sab nrauv los ntawm kev hloov pauv ntawm cov qauv kev ua haujlwm, thiab tom qab ntawd qhov poob ntawm kev siv tus nqi. Nws yog tawg, nplaum, hardened, softened, hmoov, discolored, mildew thiab hais txog.
Tsib, kev faib roj hmab
⒈ Raws li nws cov morphology: nws tau muab faib ua cov roj hmab loj heev, latex, kua roj hmab thiab hmoov roj hmab rau roj hmab colloidal dej dispersion;
Cov kua roj hmab yog cov roj hmab oligomer, tsis vulcanized ua ntej cov kua dej dav dav;
Powder roj hmab yog kev ua cov latex rau hauv cov hmoov, los pab txhawb kev sib xyaw thiab kev tsim khoom.
Thermoplastic roj hmab, tsim nyob rau hauv 1960s, yog tsim los ntawm cov txheej txheem ntawm thermoplastic es tsis txhob ntawm chemical vulcanization.
B. Roj hmab tuaj yeem muab faib ua ob pawg raws li kev siv hom dav dav thiab hom tshwj xeeb. Nws yog ib qho insulator thiab tsis ua hluav taws xob yooj yim, tab sis yuav dhau los ua tus neeg xyuas pib yog tias nws raug dej los yog qhov kub sib txawv. Kev coj yog kev txhawj xeeb nrog qhov yooj yim ntawm kev coj ntawm electrons hauv molecules lossis ions hauv ib yam khoom.
⒊ Raws li qhov chaw thiab cov txheej txheem ntawm cov khoom siv raw, cov roj hmab tuaj yeem muab faib ua cov roj hmab ntuj thiab cov roj hmab hluavtaws. Ntawm lawv, kev siv roj hmab ntuj tso nyiaj rau 1/3, hluavtaws roj hmab siv nyiaj rau 2/3.
Nws tuaj yeem muab faib ua plaub pawg: roj hmab khoom (tseem hu ua roj hmab qhuav), emulsion roj hmab (hu ua latex), kua roj hmab thiab hmoov roj hmab.
⒌ Raws li kev ua tau zoo thiab kev siv roj hmab: ntxiv rau cov roj hmab ntuj, cov roj hmab hluavtaws tuaj yeem muab faib ua cov roj hmab hluavtaws, cov roj hmab semi-general hluavtaws, cov roj hmab hluavtaws tshwj xeeb thiab cov roj hmab hluavtaws tshwj xeeb.
Raws li lub cev daim ntawv ntawm cov roj hmab, cov roj hmab tuaj yeem muab faib ua cov kua nplaum tawv thiab cov kua nplaum mos, cov kua nplaum nyoos thiab cov kua nplaum sib xyaw, thiab lwm yam.
Raws li nws cov kev ua tau zoo thiab kev siv, nws tau muab faib ua cov roj hmab dav dav thiab cov roj hmab tshwj xeeb.
Rau, txoj kev loj hlob ntawm cov roj hmab
Kev lag luam roj hmab yog ib qho ntawm cov kev lag luam tseem ceeb hauv kev lag luam hauv teb chaws. Nws tsis tsuas yog muab cov khoom siv roj hmab uas muaj teeb pom kev zoo xws li cov khoom siv kho mob niaj hnub rau tib neeg lub neej txhua hnub, tab sis kuj muab ntau yam khoom siv roj hmab los yog cov khoom siv roj hmab rau cov kev lag luam hnyav thiab cov lag luam tawm tshiab xws li mining, tsheb thauj mus los, kev tsim kho, machinery thiab electronics. Pom tau, kev lag luam roj hmab muaj ntau yam khoom, kev lag luam rov qab yog qhov dav heev.
Nyob rau hauv xyoo tas los no, kev lag luam roj hmab tau muaj ntau txoj kev loj hlob, kev lag luam subdivision tau ruaj khov thiab nce, kev lag luam roj hmab tshiab tau txhim kho sai, tab sis tib lub sijhawm, kev lag luam roj hmab kuj muaj ib puag ncig, kev pab cuam, kev puas tsuaj, kev tsim kho tshiab. thiab lwm yam teeb meem.
Txoj kev loj hlob zeem muag ntawm kev lag luam roj hmab hauv Suav teb yog dav. Cov khoom lag luam ntawm cov roj hmab kev lag luam yuav muaj kev hloov pauv zoo, cov khoom tshiab, cov khoom siv hloov pauv, cov khoom siv tshiab, kev siv technology tshiab nthuav dav, kev siv tshuab ntau lawm tau pom tseeb.
Cov yam ntxwv ntawm kev lag luam roj hmab txiav txim siab tias thaum kev lag luam roj hmab ntawm ib lub teb chaws paub tab, qhov xwm txheej ntawm kev lag luam thiab kev lag luam ntawm tag nrho cov kev lag luam yuav muaj kev sib raug zoo: qhov ntev ntawm nws lub voj voog kev loj hlob yog sib npaug rau qhov ntev ntawm kev lag luam. economic voj voog ntawm lub teb chaws, tus qauv yog tib yam; Tab sis vim hais tias kev lag luam roj hmab belongs rau kev lag luam yooj yim, nws lub voj voog hloov me ntsis ua ntej ntawm kev hloov pauv nyiaj txiag. Tsis tas li ntawd, kuj vim tias kev lag luam roj hmab yog nyob rau pem hauv ntej kawg ntawm cov saw hlau ntawm kev lag luam hauv lub teb chaws, nws qhov kev hloov pauv hloov pauv hloov pauv me dua li ntawm qhov kawg kev lag luam saw, tab sis kuj me dua li ntawm tag nrho kev lag luam. Yog li ntawd, los ntawm qhov kev xav ntawm kev lag luam peev, kev lag luam roj hmab paub tab yog nyob ze rau cov nyiaj tau los peev kev lag luam. Tuam Tshoj txoj kev lag luam roj hmab yog nyob rau hauv lub sij hawm ntawm kev loj hlob. Kev lag luam roj hmab hauv ntau qhov chaw tsis yog tsuas yog ua kom ceev cov txheej txheem ntawm Tuam Tshoj txoj kev lag luam, tab sis kuj tseem ua rau cov xwm txheej zoo ntawm kev tsim kho kev lag luam thiab kev loj hlob. Juxian County hauv Shandong, Hebei thiab lwm qhov chaw uas tsim kev lag luam roj hmab yog Yunnan, Guangdong.
Xya, ua cov roj hmab
Cov txheej txheem no suav nrog plasticizing, sib tov, calendering lossis extrusion, molding thiab vulcanization thiab lwm yam txheej txheem, txhua tus txheej txheem muaj cov kev xav tau sib txawv rau cov khoom, feem ntau nrog cov haujlwm pabcuam.
Txhawm rau kom muaj peev xwm ntxiv ntau yam uas yuav tsum tau ua rau cov roj hmab, cov roj hmab nyoos ua ntej yuav tsum tau muab cov yas los txhim kho nws cov plasticity; Tom qab ntawd los ntawm kev sib xyaw cov pa roj carbon dub thiab ntau yam roj hmab additives thiab roj hmab sib npaug sib xyaw rau hauv roj hmab; Cov khoom siv roj hmab yog nias tawm kom ua rau qee yam zoo li tsis muaj; Thiab tom qab ntawd ua rau nws tom qab calendering dai cov kua nplaum los yog kua nplaum coated textile cov ntaub ntawv (los yog nrog cov ntaub ntawv hlau) ua ke ua cov khoom ib nrab tiav; Thaum kawg, cov khoom yas semi-tiav yog vulcanized thiab ua rau hauv cov khoom kawg nrog siab elasticity.
Rau cov khoom uas muaj siab precision, xws li roj ntsaws ruaj ruaj, O-rings, ntsaws ruaj ruaj thiab lwm yam khoom siv roj hmab, nws tseem yuav tsum tau nqa tawm trimming thiab burring ua. Txoj kev xaiv yog phau ntawv trimming, mechanical trimming thiab khov trimming.
Los ntawm txhais tes trimming: siv zog ua hauj lwm, tsis tshua muaj efficiency, tsawg tsim nyog tus nqi.
Mechanical trimming: tsuas yog xuas nrig ntaus, sib tsoo log thiab puag ncig riam trimming, haum rau cov khoom tshwj xeeb uas tsis muaj qhov yuav tsum tau ua.
Frozen edging: Cov khoom siv tshwj xeeb khov edging tshuab, lub hauv paus ntsiab lus yog siv cov kua nitrogen (LN2) ua kom cov ntug ntawm cov khoom tiav lawm nkig ntawm qhov kub thiab txias, siv cov khoom khov khov (pellets) los tsoo cov ntug nyoos, kom sai. tshem tawm ntug ntug. Frozen trimming muaj kev ua haujlwm siab, tus nqi qis thiab ntau yam khoom siv, uas tau dhau los ua cov txheej txheem tseem ceeb.
Yim, kev tshawb nrhiav roj hmab zoo
Hauv cov khoom siv roj hmab thiab cov khoom lag luam muaj cov kev xav tau zoo, xws li lub zog tensile, elastic modulus, elongation, aging kuj thiab lwm yam. Cov khoom siv roj hmab siv nyob rau hauv qhov kev ua haujlwm siab, cov kev txwv no feem ntau xav tau.
Pawg neeg ua haujlwm ntawm cov khoom siv roj hmab tau tsim nyob rau theem pib ntawm kev txhim kho roj hmab hauv Suav teb, lub luag haujlwm rau kev tshawb fawb thiab kev tsim cov roj hmab, kev kawm, kev saib xyuas zoo thiab lwm yam haujlwm.
1. Kev sim ntawm qhov hnyav nce tsis kam mus rau nruab nrab
Cov khoom tiav tuaj yeem raug kuaj, tsau rau hauv ib lossis ob peb lub xov xwm xaiv, hnyav tom qab qee lub sijhawm kub, thiab cov khoom siv tuaj yeem suav tau raws li qhov hloov pauv ntawm qhov hnyav thiab hardness.
Piv txwv li, soaked nyob rau hauv 100 degree roj rau 24 teev, nitrile roj hmab NBR, fluorine roj hmab, neoprene roj hmab CR loj thiab hardness hloov tus nqi yog tsawg heev, thiab ntuj roj hmab NR, ethylene propylene roj hmab EPDM, styrene butadiene roj hmab SBR hnyav tshaj ob npaug thiab. hardness hloov zoo heev, ntim expansion yog pom tseeb heev.
2. Kub huab cua aging sim
Siv cov qauv ntawm cov khoom tiav thiab muab tso rau hauv lub thawv kev laus rau ib hnub los soj ntsuam qhov tshwm sim tom qab kev laus. Muaj peev xwm graded aging maj mam cua sov. Piv txwv li, ntawm 150 degree, neoprene roj hmab CR, ntuj roj hmab NR, styrene butadiene roj hmab SBR yuav nkig, nitrile butadiene roj hmab NBR, ethylene propylene roj hmab EPDM thiab elastic. Nce mus rau 180 degree zoo tib yam nitrile roj hmab NBR yuav nkig so; Thiab ntawm 230 degree hydrogenated nitrile cov pos hniav HNBR tseem yuav nkig, cov pos hniav fluorine thiab silica gel tseem muaj elasticity zoo.
3. Txoj kev combustion
Nqa ob peb qhov qauv thiab hlawv rau saum huab cua. Saib xyuas qhov tshwm sim.
Feem ntau hais lus, fluorine roj hmab, neoprene roj hmab CR los ntawm qhov hluav taws kub, txawm tias qhov hluav taws kub tsawg dua li cov roj hmab NR, ethylene propylene roj hmab EPDM. Tau kawg, yog tias koj saib ze, lub xeev ntawm kev sib xyaw, xim, thiab tsw tuaj yeem qhia koj ntau. Piv txwv li, NBR / PVC yog siv nrog kua nplaum. Thaum muaj hluav taws, qhov hluav taws kub nyhiab tshwm sim, zoo li dej, thiab cov pa taws yog tuab thiab qaub. Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias qee zaum ntxiv cov nplaim hluav taws tab sis tsis muaj cov pos hniav halogen tseem yuav tua tus kheej ntawm qhov hluav taws kub, qhov no yuav tsum tau ua ntxiv los ntawm lwm txoj kev.
4 Kev ntsuas qhov ntsuas tshwj xeeb
Siv lub ntsuas hluav taws xob lossis ntsuas qhov ntsuas, qhov tseeb rau 0.01 grams, ntxiv rau ib khob dej, plaub hau tuaj yeem ua tau.
Feem ntau hais lus, qhov feem pua ntawm cov roj hmab fluorine yog qhov loj tshaj plaws, siab tshaj 1.8, thiab qhov feem ntawm CR ntawm neoprene roj hmab yog ntau tshaj 1.3, uas tuaj yeem suav tias yog cov roj hmab no.
5 Txoj kev ntsuas kub tsawg
Coj ib qho qauv ntawm cov khoom tiav thiab tsim kom muaj qhov chaw qis qis nrog cov dej khov qhuav thiab cawv. Tsau cov qauv hauv qhov chaw kub qis rau 2-5 feeb, ntawm qhov ntsuas kub uas tau xaiv kom hnov qhov degree ntawm hardness. Piv txwv li, hauv qab rho tawm 40 degree, tib lub siab kub thiab roj kuj zoo heev silicone thiab fluorine roj hmab, silicone yog mos.
