Cov yam ntxwv cuam tshuam rau lub Shrinkage ntawm Rubber Compounds

1. Taw qhia

1.1 Qhov tseem ceeb ntawm Shrinkage tus nqi ntawm cov khoom siv roj hmab

Ib qho tseem ceeb ntawm kev ntsuas kev ua tau zoo rau cov khoom siv roj hmab yog lawv cov nqi shrinkage. Nws muaj kev cuam tshuam ncaj qha rau cov khoom 'kev ua tau zoo, zoo li, thiab qhov tseeb qhov tseeb. Tus nqi siab ntawm shrinkage yuav ua rau muaj qhov tsis zoo ntawm qhov chaw, qhov khoom loj sib txawv, thiab lwm yam teeb meem uas yuav cuam tshuam qhov zoo ntawm cov khoom. Yog li ntawd, ib qho ntawm cov thev naus laus zis tseem ceeb tshaj plaws hauv cov txheej txheem kev tsim cov roj hmab yog kev tswj hwm thiab ua kom cov nqi qis tshaj ntawm cov khoom siv roj hmab.

1.2 Txheej txheem cej luam ntawm cov ntsiab lus tseem ceeb cuam tshuam rau tus nqi shrinkage

• Roj Hmab formula: Tus nqi shrinkage yuav txawv nyob ntawm seb hom thiab ntau npaum li cas ntawm fillers, plasticizers, thiab raw cov ntaub ntawv siv hauv roj hmab.
• Moulding txheej txheem: Shrinkage cwj pwm yuav txawv nyob ntawm seb hom molding siv, xws li txhaj tshuaj molding los yog compression molding.
• Moulding tej yam kev mob: Lub shrinkage tus nqi yog ho cuam tshuam los ntawm kev xaiv ntawm cov txheej txheem tsis, xws li kub, siab, thiab tuav lub sij hawm.
• Tom qab ua tiav: Qhov kawg shrinkage tus nqi kuj tseem yuav cuam tshuam los ntawm cov txheej txheem tom qab xws li demolding, txias, thiab kev kho cua sov.

2. Kev cuam tshuam ntawm cov qauv ntawm cov qauv ntawm cov nqi shrinkage

2.1 Kev cuam tshuam ntawm cov roj hmab sib txawv ntawm tus nqi shrinkage

2.1.1 Ntuj roj hmab, styrene-butadiene roj hmab, chloroprene roj hmab, thiab lwm yam.

Ib qho ntawm cov ntsiab lus tseem ceeb cuam tshuam rau tus nqi shrinkage yog hom roj hmab. Cov cwj pwm shrinkage ntawm ntau hom roj hmab sib txawv vim qhov txawv ntawm lawv cov qauv molecular, polarity, crosslinking ntom, thiab lwm yam khoom.

• Vim tias cov roj hmab ntuj (NR) muaj cov saw hlau ntev dua thiab qis dua qhov sib txuas ntawm qhov sib txuas-feem ntau ntawm 10 thiab 15 feem pua-nws shrinks sai dua.
• Styrene monomer yog ntxiv rau styrene-butadiene roj hmab (SBR), uas ua rau muaj zog molecular polarity, ntau dua crosslinking ntom, thiab txo qis qis (feem ntau yog 5-10%) piv rau cov roj hmab ntuj.
• chloroprene roj hmab (CR) yog tus cwj pwm los ntawm qhov muaj cov tshuaj chlorine atoms, muaj kev sib txuas ntau dua, muaj zog molecular polarity, thiab qis qis qis (feem ntau 3-8%).
• Lwm tus, suav nrog nitrile roj hmab (NBR) thiab ethylene-propylene roj hmab (EPDM), muaj qhov sib txawv shrinkage zog vim lawv txawv molecular polarities thiab cov qauv, uas hu rau kev tshawb nrhiav ntxiv.

2.2 Qhov cuam tshuam ntawm cov ntsiab lus muab tub lim rau shrinkage

2.2.1 Inorganic fillers vs. organic fillers

Roj hmab cov khoom shrinkage tus nqi kuj tseem cuam tshuam los ntawm hom thiab ntau npaum li cas ntawm cov khoom siv. Feem ntau, lawv tau muab cais ua ob pawg: inorganic thiab organic fillers.

• Feem ntau hom inorganic fillers muaj xws li talc, dolomite hmoov, dawb carbon dub, thiab carbon dub. Vim tias lawv muaj zog dua thiab muaj cov qauv ntau dua, cov khoom siv no feem ntau yuav txwv tsis pub cov roj hmab matrix shrinks.
• Txij li cov organic fillers zoo li cellulose thiab ntoo hmoov shrinks ntau dua li lwm cov fillers ua, ntxiv ntau dhau ntawm lawv tuaj yeem ua rau tag nrho cov shrinkage nce.

2.2.2 Kev sib raug zoo ntawm cov ntsiab lus muab tub lim thiab shrinkage

Feem ntau hais lus, cov khoom siv roj hmab yuav txo qis dua qhov muab tub lim ntau dua. Qhov no yog vim qhov tseeb tias cov khoom tawv tawv tuaj yeem tiv thaiv cov roj hmab matrix los ntawm deforming vim shrinking.

Ntawm qhov tod tes, cov ntsiab lus muab tub lim ntau dhau yuav ua rau cov khoom lag luam zoo thiab kev tsim kho. Yog li ntawd, nws yog ib qho tseem ceeb rau optimize thiab sib npaug shrinkage tswj nrog lwm yam kev xav tau kev ua haujlwm.

Kev tswj cov ntsiab lus muab tub lim ntawm 30 thiab 50 feem pua ​​​​feem ntau yog qhov kev txiav txim siab zoo vim nws tuaj yeem ua tiav txo qis qis yam tsis muaj kev cuam tshuam rau lwm yam kev ua haujlwm. Nws yog ib qho tsim nyog los lim thiab hloov kho hom muab tub lim thiab cov ntsiab lus raws li qhov xav tau ntawm cov khoom.

2.3 Kev cuam tshuam ntawm lwm yam additives

2.3.1 softener, stabilizer, colorant, thiab lwm yam.

Softener:

Roj hmab tuaj yeem elongate thiab ua cov yas ntau dua nrog plasticizer, tab sis shrinkage kuj yuav nce. Feem ntau, shrinkage nce nrog nce plasticizer concentration.

Stabilizer:

Los ntawm kev nce qhov sib txuas ntawm qhov sib txuas ntawm cov roj hmab, cov stabilizers xws li cov tshuaj antioxidants thiab cov tshuaj tiv thaiv kab mob tuaj yeem raug ntxiv kom txo qis. Txawm li cas los xij, embrittlement tuaj yeem tshwm sim los ntawm overadding.

Ntxiv:

Tshwj tsis yog tias tus nqi ntxiv yog siab heev, kev qhia txog cov xim zoo li cov xim xim thiab cov xim xim feem ntau tsis muaj kev cuam tshuam rau qhov shrinkage.

Lwm tus:

Ntau me ntsis ntawm vulcanizing tus neeg saib xyuas, accelerator ntawm vulcanization, foaming tus neeg saib xyuas, thiab lwm yam, kuj yuav muaj qee yam cuam tshuam rau shrinkage.

3. Kev cuam tshuam ntawm cov txheej txheem ntawm kev shrinkage

3.1 Kev cuam tshuam ntawm kev sib xyaw ua ke ntawm shrinkage

3.1.1 Ceev, kub, sijhawm, thiab lwm yam.

Kev sib tov ceev:

Ib qho ceev uas ceev heev yuav ua rau cov roj hmab molecular saw, txo qhov hnyav molecular thiab nce shrinkage. Tswj nws ntawm 30 thiab 60 rpm feem ntau yog qhov zoo dua.

Qhov kub ntawm kev sib xyaw:

Txhua qhov kub siab dhau tuaj yeem ua rau cov roj hmab molecules ' thermal deterioration thiab ua rau shrinking ntxiv. Qhov sib tov kub yog feem ntau tswj ntawm 110 thiab 160 degree.

Lub sij hawm siv mixing:

Lub sijhawm sib xyaw ua ke ntev ntev tuaj yeem ua rau shrinkage thiab ntxiv molecular hnyav txo. Txawm li cas los xij, lub sijhawm me me tiv thaiv cov fillers los ntawm kev tawg tag. Tswj nws li peb mus rau kaum feeb yog feem ntau txaus.

Order of mix:

Txhawm rau txo qis qis thiab tiv thaiv kev sib sau ua ke, nws raug nquahu kom siv cov khoom siv tawv ua ntej, ua raws li cov roj hmab muag.

3.2 Cov nyhuv ntawm vulcanization tej yam kev mob ntawm shrinkage

3.2.2 Vulcanization kub, lub sij hawm, siab, thiab lwm yam.

Kub ntawm vulcanization:

Kev kub siab heev tuaj yeem ua rau cov roj hmab chains 'kev sib txuas ntawm kev sib txuas thiab thermal deterioration, uas yuav ua rau kom shrinkage. Nws yog ib txwm nyiam kom nws nyob ntawm 150 thiab 180 degree.

Lub sijhawm ntawm vulcanization:

Lub sijhawm ntau dhau tuaj yeem ua kom nrawm nrawm thiab txhawb nqa qhov sib txuas sib txuas. Txawm li cas los xij, vulcanization tsis ua tiav hauv lub sijhawm luv luv. Feem ntau hauv 10 mus rau 30 feeb.

Siab thaum lub sij hawm vulcanization:

Cov roj hmab lub ntim yuav raug compressed los ntawm lub siab ntau dhau, uas yuav ua kom nrawm nrawm. Kev tswj xyuas qhov siab ntawm 5 thiab 15 MPa yog qhov tsim nyog.

3.3 Cov nyhuv ntawm molding txheej txheem ntawm shrinkage

3.3.1 Txhaj tshuaj molding vs extrusion

Kev txhaj tshuaj sai thiab cov txheej txheem ua kom txias hauv kev txhaj tshuaj molding yuav ua rau shrinkage ntau dua. Extrusion molding shrinks tsawg sai thiab yog piv rau sluggish.

3.3.2 Txias tus nqi

Tus nqi ntawm shrinking nce nrog txias ceev. Kev tswj tus nqi cua txias yog li ntawd tseem ceeb los tiv thaiv overcooling.

4. Kev cuam tshuam ntawm ib puag ncig yam cuam tshuam rau shrinkage

4.1 Cov nyhuv ntawm qhov kub thiab txias ntawm shrinkage

Roj hmab lub thermal expansion coefficient yuav nce nrog qhov kub thiab txias, ua kom tus nqi ntawm shrinkage.

Roj hmab molecular chains tseem yuav muaj kev sib txuas ntawm kev sib txuas thiab thermal tawg ntawm qhov kub thiab txias, uas yuav ua rau kom qis dua.

Cov roj hmab uas muaj ntau yam sib txawv kuj yog qhov kub thiab txias. Qee hom roj hmab muaj kev cuam tshuam ntau dua rau kev hloov pauv hauv qhov kub thiab txias.

Txhawm rau txo qis qis, qhov kub thiab txias yuav tsum raug zam txhua qhov chaw uas muaj peev xwm siv thiab khaws cov khoom siv roj hmab. Passive lossis nquag tswj cov txheej txheem tuaj yeem siv rau cov khoom tseem ceeb.

4.2 Qhov cuam tshuam ntawm cov av noo ntawm shrinkage

Feem ntau hais lus, av noo tsis tshua muaj kev cuam tshuam rau roj hmab shrinkage. Ntawm qhov tod tes, kev nqus dej noo yuav ua rau qee cov khoom siv roj hmab uas muaj cov khoom nqus dej kom nthuav dav, ua kom lub ntim tag nrho thiab txo qis.

Roj hmab tau yooj yim absorbs noo noo thiab softens nyob rau hauv high humidity ib puag ncig, uas yuav ua tau rau cov khoom tsis ruaj tsis khov. Overdrying kuj tuaj yeem cuam tshuam rau shrinkage thiab ua rau roj hmab embrittlement.

Yog li, nws yog ib qho tseem ceeb los tswj cov av noo kom zoo, feem ntau ntawm 40 thiab 70 feem pua ​​​​ntawm cov av noo, thaum siv thiab khaws cov khoom siv roj hmab. Thaum xav tau, ntsuas dej noo tuaj yeem siv tau.

5. Kev ua kom zoo tshaj plaws thiab kev tswj xyuas

5.1 Optimization ntawm formulation yam

1. Xaiv cov khoom siv roj hmab nrog me me, xws li silicone lossis nitrile roj hmab.
2. Txhawm rau txo qis qis, txiav txim siab thiab sib xyaw ua ke sib txawv-xws li talc, dawb carbon dub, thiab carbon dub-tsim nyog.
3. Ntxiv qee cov tshuaj tiv thaiv shrinkage, xws li polyethylene, low-molecular-weight polypropylene, thiab lwm yam.
4. Txhim kho qhov kev sib txuas sib txuas los ntawm kev ntxiv cov tshuaj muaj txiaj ntsig, hloov kho cov ntsiab lus sulfur, thiab lwm yam.

5.2 Optimization ntawm cov txheej txheem tsis

• Tswj cov pace, sijhawm, thiab kub ntawm kev sib xyaw kom tsis txhob muaj degradation ntau dhau.
• Txhawm rau tswj cov qib crosslinking, kho cov vulcanization kub, lub sij hawm, thiab siab tsis.
• Txiav txim siab txog cov txheej txheem molding tsim nyog, xws li extrusion lossis txhaj tshuaj molding, thiab tswj tus nqi cua txias.
• Cov txheej txheem ntawm lub sijhawm ntsuas ntsuas ntsuas thiab hloov kho yuav tsum tau ua nrog kev tshawb pom hauv online thiab lwm yam txheej txheem.

5.3 Kev tswj hwm ib puag ncig

1. Ua kom tsis txhob muaj qhov kub thiab txias thiab, yog tias tsim nyog, ua qhov ntsuas kub kom tsim nyog.
2. Cov av noo me ntsis yuav tsum tau khaws cia kom tsis txhob ziab dhau los yog nqus dej noo.
3. Kev ntsuas kev ntsuas xws li dej tsis kam thiab rwb thaiv tsev kub tuaj yeem siv rau cov khoom tseem ceeb.