Siv PVA Adhesives los pab ntxiv kev tso tseg dej rau kev siv ntawm ntuj teb

Paub txog qhov muag hniav thiab qhov yooj yim ntawm cov PVA adhesive tshaiv

Qhov muag hniav hauv plab ntawm polyvinyl acetate (PVA) emulsion

PVA glues feem ntau yooj yim tiv thaiv dej vim tias lawv muaj cov hydroxyl groups nyob rau hauv polymer chain uas tseem nyiam sib cuag nrog hydrogen nrog xab dej. Cov kev suav ntawm polymer chemistry qhia tias PVA feem ntau tuaj yeem dhau los ntawm 10 mus rau 15% ntawm nws lub cej teev thaum tshaj tawm rau qhov chaw muaj xab dej siab. Qhov zoo yog tias qhov kev nyiam dej no pab nws ntxig zoo rau ib co yam dab neeg xws li ntug thiab daim ntawv. Tab sis muaj qhov tsis zoo los. Thaum siv nyob saum toj los yog hauv qhov chaw uas tau dej rov qab rov qab, qhov glue tsis tuaj nqa ntev. Yog li ntawd ntau tus khaub ncaws txiab PVA rau qee yam kev siv uas kev tiv thaiv dej yog qhov tseem ceeb dua.

Qhov feem ntau tshwm sim khiav hauv PVA adhesives thaum siv saum toj

Kev tshaj tawm rau dej plhu los yog xab dej cuam tshuam peb hom kev kho mob tshiab rau hauv PVA tsis muaj kev hloov pauv:

• Plasticization : Dej nkag mus rau hauv adhesive film, ua rau nws lub thawj meej sovet
• Swelling-induced stress : Kev ntuav hla ntawm 3–5% tsim kev nyuaj siab hauv qhov chaw sib xyuas
• Kev hydrolysis ntawm kab sib txig polymer : Xwv muaj dej tshuaj rau cov khoom sib thooj covalent ntawm vinyl acetate monomers

Ob qho no txawv txav mus rau kev sib xyuas nyuaj siab thaum muaj ntau zog, kev sib tso tawm ntawm qhov sib xyuas, thiab lub sijhawm ntev hauv dej ntsuab.

Tus leej nqi txog kev phom sij tawm: tus naj npawb dej nyob hauv thiab kev txo hlo sib xyuas

Kev soj ntsuam zoo dua pom tias cov PVA adhesives yooj yim loss 50–70% ntawm lub hlo sib xyuas pomm tom qab 30 hnub nyob hauv 85% relative humidity. Tus naj npawb dej nyob hauv sib piv nrog kev phom sij tawm:

Cov Lus Qhia Kem Txheej Kev Siv Rau Kev Ntxiv Kev Tsoj Liab ntawm PVA Adhesives

Sau Ntawv Cov Pawg Tuaj Rau Hauv PVA Adhesive Formulations

Cov khaub tshwj tsis nyob rau dej tuaj yeem muab cov nuj nqaij hydrophobic los ntawm alkyl lossis cov kab nyiaj aromatic rau hauv cov kab duab polymer polyvinyl acetate. Thaum lawv ua li no, nws tsim tau ib qhov ujzlwm sterique uas tshwm sim thaiv dej los ntawm kev txuam nrog rau cov khoom. Txhawj tias hais tias nyob rau hauv European Polymer Journal pub nyob rau 2012, qhov kev xaiv no tuaj yeem sau ntxoov kev dhos dej los li 40%. Qhov tseem ceeb tshaj plaws ntawm cov kev hloov no yog tias tsis obob tias muaj cov hloov tam sim no, cov khoom yuav tsum zoo sib nyob nrog cov khoom zoo li ntawv thiab cov khoom lo rau ntawv xim uas kev nyob sib thooj zoo yog qhov tseem ceeb tshaj plaws rau kev siv hauv keev ceeb.

Kev Sib Tau Los Yog Acetalization Rau Kev Lwm Ntau Txog Dej

Qhov kev sib ntaus sib tua ntawm esterification ua haujlwm los rhuav tshem cov nhom hydroxyl nyob rau hauv PVA los nrog cov chaw sib xyaw ester, feem ntau yog ua nrog cov acid carboxylic lossis cov anhydride. Qhov kev hloov kem no txo qis dab tsi tiv thaiv dej, nyob rau sab 65 mus rau 80% txiab tias nyob rau hauv qhov chaw. Tom qab ntawd muaj acetalization, uas pheej xwm thaum cov khoom sib tham nrog aldehydes zoo li formaldehyde. Qhov no ua rau muaj cov chaw sib ntxig cyclical uas tiaj tus block dej kom tsis tau nkag. Txawm tseem ceeb dua vim nws tuaj yeem txeem 85 mus rau 90% ntawm qhov tseem ceeb tshaj plaws. Ob qho kev sib tham no ua rau khoom meej dua, yog li cov khaub ncaws yuav tsum nrhiav kom pom qhov ratio tswv yim los tso kom khoom tsis loj thiab tsis hlo tshem kev ua haujlwm.

Sau cov Khoom Siv Silane los Tiv Thaiv Kev Tso Zog

Kev hloov kho los ntawm silane tau pab txhim khu kev nyiam loj dua nyob rau qhov chaw muaj dej ntau los ntawm kev tsim cov cuab yeej sib thooj rau cov ntsiab lus uas muaj hydroxyl. γ-Glycidoxypropyltrimethoxysilane (GPTMS), piv txwv li, ua raws li ib qhov kheej tshoob molecular, pab txhim kho kev nyuaj siab rau sab nraud, metals, thiab tshuab ntxuav. Cov chais hluas uas muaj silanes tau txhim kho kev nyuaj siab rau sab nraud uas tshaj tawm 8 MPa nyob rau saum 85% xim ntxuav.

Qhov sib txawv nyob rau hauv kev tsim kom muaj kev ceev thiab kev tiv thaiv rau dej tom qab kev hloov kho los ntawm cheeb

Kev sib thooj thiab kev sib thooj rau cov adhesive PVA zoo tshaj

Aldehyde-based thiab metal ion crosslinkers: Txhawb ntau tshaj hauv qab chaws nyias

Saij kemis lo tshuaj crosslinking tsim PVA mus rau hauv lub network 3D uas tiv thaiv nyias. Qhov kev siv formaldehyde-based systems txhawb ntau dua li 35–45% hn compared to uncured PVA (Journal of Adhesion Science, 2023), thaum aluminum-ion crosslinkers pab tiv thaiv hydrolysis hauv qab chaws muaj nyias. Kev siv tshuaj txaus siab yuav tsum muaj kev kho kom meej meej (4.5–5.5) kom tiv thaiv kev gelation ua ntej.

Isocyanate thiab borate crosslinkers: Thaiv kev nyab xeeb thiab kev phem

Thaum cov isocyanates tau siv hauv matrices PVA, lawv tsim cov khoom uas cuam tshuam rau humidity cured urethane bonds uas pab txo qhov tshaib ntawm dej ntau dua li 50%. Tab sis muaj ib qhov nyuaj: cov khoom no tso VOCs rau hauv av, yog li ua kom meej meej yuav tsum muaj lub system tso av tshiab. Rau cov neeg xav tau ib yam dab neeg safer, cov borate crosslinkers yuav zoo dua. Lawv tsim cov kev sib raug zoo txaus siab nrog cov hydroxyl groups hauv PVA thiab tsis muaj cov toxins. Ntawm kev xa mus dhau los ntawm 2023 kuj muaj kev pom zoo tshaj plaws. Cov adhesives uas tau hloov los ntawm borate kuj tseem muaj txoj caij nyoog nyob ib leeg txog 82% tom qab nyob ruaj ruaj ib xyoo. Qhov no tsis phem heev thaum soj ntsuam nrog rau cov isocyanate systems feem ntau uas tseem muaj txoj caij nyoog txog 94% nyob rau qhov chaw tseem ceeb.

Dosage zoo tshaj plaws thiab qhov chaw kho kom zoo tshaj plaws rau kev sib thooj ntau tshaj plaws

Khiav txwv li 8% qhov loj ntawm cov khoom sib thooj yuav ua rau cuam kom meem, tso peev tsis tau hauv kev tshav tawm los ntawm 25–30% (Polymer Engineering Reports, 2023).

Cov khoom sib xyaw vinyl acetate-ethylene (VAE) rau kev tiv thaiv zoo dua hauv kev nyob nrog dej

Cov VAE sib xyaw muaj 92% kev nyiaj ruaj siab tom qab 500 zaug hluv hluas (0–100% RH), zoo dua PVA saum paib plab. Cov yam ntxwv ethylene tsim cov chaw kheej uas tiv thaiv dej thiab tsis pub dej tshav kom cuam, thaum twg kuj tseem nyob ib puag ncig 300%—qeev tshaj plaws rau kev daws teeb meem thaum sib txuas nyob ze phab ntsa hauv plhaus.

Sau acrylic monomers mus pab txhim kho kev tsim film thiab kev tiv dej

Ntxiv 15–20% acrylic esters (xws li butyl acrylate, methyl methacrylate) los dimin duab ntau ntawm dej los ntawm 3 qhov kev ua haujlwm:

1. Kev tsim cov kab ntsiag tawv kheej
2. Kev pab kom dej nyob rau hauv qhov chaw (ntsi thaiv tshwm sim los ntawm 75° mus ncig 52°)
3. Kev pab tsoom dej sov saum npoo ntawm 10°C
   Ob qho no txoj kev tsim khoom tau txais standards EN 204 D3 rau 20 feeb kom dej tsis tuaj, thaum kawg siv dua li 15 feeb.

Kev sib piv Txij Ci: PVA Thaujlwm vs. Polyurethane (PUR) Adhesives

Tus nqi muaj zog kom dej tsis tuaj: PVA Thaujlwm Versus PUR Adhesives

PVA cov cuab meej uas muaj keem caij ntau dua tuaj yeem tiv thaiv dej zoo los ntawm kev sib txig sib xig. Cov khoom no feem ntau hla kawg dua li 85% ntawm lawv lub zog dhau los tom qab tau nyob hauv dej ib ncig ib pliag ib peb hnub. Xyuas rau polyurethanes, lawv tsim cov network sib txuas uas tiv thaiv dej zoo li cas li cas. Cov leej huam sib xyaw PUR feem ntau hla kawg dua li 85% zog tom qab tau nyob ib si 500 teev hauv av chw txom tej sib npaug raws standards ASTM. Polyurethanes yog tus vij tes hauv kev tiv thaiv dej ntau xyuas. Tab sis, PVA cov duais tshiab feem ntau tuaj yeem tiv thaiv dej zoo hauv kev test ntau thiab siv nyob hauv kev tsim kho sab nraud.

Kev su kom zooj yuav tsum tau ntawm PVA ntau zog heev thiab PUR systems

Cov tshuab ntxig Polyurethane (PUR) feem ntau muaj tus nqi ib liter yog li 2.5 mus rau 3 zaug tshaj cov PVA tau muab tso ua ke, thiab lawv feem ntau xav tau cov hkeem ntxig zoo tshaj thiab qhov chaw tsim nyog rau kev sib xyaw. Txhawm rau txheeb xyuas ib co ntawm niaj hnub kawg no, modified PVA nyuaj siab tshaj 18 mus rau 22% nyog rau kev tsim khoob ntoo rau ntuj sov vim tias tsis tas yuav tsum muaj kev tiv thaiv kom ncua tsis tuaj los. Tom qab no, PUR tsis txhob tsis muaj nyob rau hauv kev tsim khoob thiab lwm yam kev siv rau hauv dej vim tias cov tshuab ntxig no nyob tau li 8 mus rau 12 xyoo, tab sis PVA tsuas nyob tau 4 mus rau 7 xyoo. Tus nqi ntau dua no cuam tshuaj nyob rau hauv qhov chaw dej muaj lej uas kev nyob ntev yog qhov tseem ceeb tshaj plaws.

Yuav vim li cas Modified PVA Zoo Tshaj Nyob Rau Ntau Qhov Siv Rau Ntuj Sov Txh despite Mej kev Tiv Thaiv

PVA thauj ntxiv nyob qhov muaj feem ntau tshaj li 63% ntawm kev siv rau kev lag luam hluas tsev ntoo thiab chav tsev, vim nws tsis hlo plua pluag VOCs, sau ua siab ntau dua, thiab tuaj tau zoo tib yam li uas kuaj nrog qhov ceev txog -40 degrees Celsius txog 90 degrees. Lub zog sib sau ntawm PUR feem ntau yuav tshwm sim rau qhov chaw khi thiab rov qab yog tias muaj kub noo, tab sis PVA muaj qhov tshua meej meej uas tuaj yeem tso cai rau qhov kub noo thiab sib tso tseg tsis muaj teeb meem, xws li rau qhov chaw pib thiab lub vij tsis. Txoj kev tshawb nrhiav hais tias cov neeg lag luam feem ntau nyiam tswjhwm kom tsis pub muaj kev puas tsuaj ntau dua kev tswjhwm kom tsis muaj dej taws, nyob rau tib cheem kawg, thiab muaj feem ntau tshaj li 75% ntawm cov neeg nyob zeeg saib qhov nyob ntev thiab qhov kub noo txaus siab dua qhov tsis muaj dej taws.

Cov kev siv nyob hauv cheeb tsam ntawm PVA adhesives uas tsis muaj dej taws rau hauv tsev thiab khoom siv tsev

PVA thauj ntxiv nyob hauv Thermal Insulation Boards: Qhov kev ua haujlwm thaum muaj dej ntsuab

PVA kev sib txig adhesive uas tiv thaiv dej zoo tuaj yeem ua haujlwm zoo rau qhov chaw thermal insulation thaum lub sijhawm uas kub thiab ntxhiav ntxuas feem ntau. Muaj ib co kev sim accelerated aging uas sim qhov tshwm sim tom qab li 5 xyoo nyob ntawm av muaj lus nug zoo. PVA tau siv los txig expanded polystyrene lossis EPS boards tau npog txog 92% ntawm qhov siab tshaj tawm, tab sis PVA tsis tau txig ib yam dab tsi yog li 67% raws li lus nug ntawm Building Materials Durability Report los ntawm xyoo 2023. Qhov uas pab tau li no yog qhov sib txig hydrophobic cross links nyob rau hauv cov PVA tau muab kho. Cov no pab tiv thaiv tej teeb meem plasticization uas muab los los ntawm dej, uas txhais tau tias cov khoom no tuaj yeem tswj kom zoo ib txwm zoo thaum muaj dej ntxhiav ntxuas siab npog 85% ntev.

Siv rau hauv Outdoor Paper Products thiab Packaging: Txhim kho kev nyob dav ntawm Water-Resistant PVA

Qhov chaw tsim kho rau kev sib nqum siv cov PVA adhesive uas muaj kem tuag los tsim cov corrugated boards thiab cov lus qhia uas tuaj yooj saib xwb. Qhov kev soj ntsuam txog lub teebchaws hli ntawm xyoo 2024 pom tias cov no cuam tshwm tsawg dua li 41% ntawm cov packaging uas raug recycled kom compared to cov adhesive uas tshuav starch. Cov kev pab pawg tseem ceeb yog:

• Silane-modified PVA uas tuaj yeem nyob ib si tsis phom
• Cov acrylic-copolymer enhanced uas tuaj yeem nyob ib si thiab rov qab dua 18 zaug
• Cov UV-stabilized uas tuaj yeem tso tawm peb ntau dua li 1.5 N/mm² tom qab nyob ib si rau plaub xyoos

Ntaub ntawv txog kev ua haujlwm ntev los ntawm kev siv hauv kev tsim kho thiab hauv cheeb tsam

Ntau dua 84% ntawm cov kev tsim kho uas siv cov PVA adhesive modified tau pom zoo heev rau ib xyoos dua li 7 xyoo hauv kev siv ib si. Cov kev siv tseem ceeb yog:

Ntau yam ntaub ntawv los ntawm 12 qhov chaw siv hluv rau lawm nyob Europe (2018–2023) tso kom pom tias PVA adhesives uas tau hloov kho kim tuaj yeem tiv thaiv dej zoo li polyurethane systems thiab muaj 34% tsawg dua rau ntau yam khoom, yog li nws yog ib qho zoo tshaj rau kev tsim tsev nyob rau hauv kev tsis phem rau dej num.

FAQ

1. Qhov twg yog qhov zoo ntawm kev siv PVA adhesives uas tau hloov kho kim?

PVA adhesives uas tau hloov kho kim muaj kev tiv thaiv dej zoo dua, nyob ntev dua, thiab muaj kev nyiaj ruaj siab dua rau kev sib xyuas nyob rau hauv av thiab qhov chaw muaj dej ntau. Lawv kuj tsis tso ntau VOCs tawm, yog li nws tsis phem rau dej num.

2. PVA adhesives thiab polyurethane (PUR) adhesives sib npaug li cas nyob rau hauv kev ua haujlwm thiab nqi?

Thiab kuv PUR adhesives muaj kev tiv thaiv dej zoo dua rau lub sijhawm ntev, tab sis PVA adhesives uas tau hloov kho kim muaj nqi tsawg dua thiab zoo enough rau ntau yam kev siv nyob rau hauv av thaum tsis tas yuav tiv thaiv dej 100%.

3. Puas muaj qhov txuam txhab ntawm kev tsim nyog thiab kev tiv thaiv dej hauv PVA adhesives uas tau raug suab ntxiv?

Yus, thaum kev suab ntxiv siv khoom sib thooj tuaj yeem pab tiv thaiv dej zoo dua, tab sis nws tuaj yeem ua rau kev tsim nyog hlawv tso lic. Qhov chaw tsim khoom kho kom zoo los ntawm kev ntxiv cov monomers elastomeric los ntawm kev copolymerization.

4. Qhov twg yog ib co qhov siv theej xwm ntawm PVA adhesives uas tau raug suab ntxiv?

PVA adhesives uas tau raug suab ntxiv siv ntau hauv qhov board thermal insulation, khoom lo rau sab nraum, kev sau khoom, thiab ntau yam kev siv sib txawv hauv kev tsim kho uas xav tau kev tiv thaiv dej thiab kev hloov kub