Alkyd resins tuav ib qho ntawm txoj haujlwm ua cov khoom siv raw rau kev tsim cov xim niaj hnub thiab cov kua roj vanish. Film-forming compositions raws li lawv muaj ntau yam kev siv. Txheej cov khoom nyob ntawm seb hom resins thiab semi-tiav varnishes. Qhov dav tshaj plaws yog hloov kho cov khoom sib xyaw, vim lawv muaj cov hniav zoo nkauj thiab kev tiv thaiv zoo.
Kev piav qhia
Alkyd resins (los yog alkyds) yog esters uas tshwm sim los ntawm cov tshuaj tiv thaiv ntawm polyhydric cawv nrog polybasic acids los yog lawv cov anhydrides. Nyob rau hauv tsos, lawv yog cov nplaum nplaum nplaum, cov xim uas yog los ntawm tsaus daj mus rau xim av.
Alkyds kuj tseem ua ke nrog lwm cov resins thiab cellulose (alkyd-urea-formaldehyde, phenol-alkyd, alkyd-acrylic copolymer thiab lwm cov tebchaw). Txhawm rau txo qhov nro, butyl cawv ntxiv rau lawv cov muaj pes tsawg leeg, uas ua rau nws yooj yim dua rau ncuav cov khoom tiav.
Tshuaj muaj pes tsawg leeg thiab kev faib tawm
Alkyd resins yog systematized raws li ob peb yam:
-
Los ntawm muaj cov fatty acids nyob rau hauv muaj pes tsawg leeg: unmodified (phthalate) thiab hloov.
- Los ntawm cov ntsiab lus roj: fatty (>60%), roj nruab nrab (40-60%), lean (35-60%), ntxiv-lean (<34%). Fatty alkyds yog npaj nrog cov roj kom qhuav.
- Raws li hom cawv raws li qhov muaj pes tsawg leeg tau txais: glyphthalic, xyphthalic, pentaphthalic, etrifthalic.
- Los ntawm kev ziab kom qhuav: ziab thiab tsis ziab.
- Raws li txoj kev sib cais: diluted nrog cov kuab tshuaj organic lossis dej.
Cov tshuaj muaj pes tsawg leeg ntawm alkyd resin yog 40-60% kev daws ntawm cov tshuaj tsis muaj zog hauv cov kuab tshuaj organic.
Ntse
Cov khoom ntawm alkyds nyob ntawm hom polyhydric cawv, nws cov concentration thiab muaj lwm yam khoom. Aromatic Cheebtsam muab coatings raws li cov compounds hardness thiab hnav tsis kam, aliphatic polyols - elasticity, cycloaliphatic structural units - sib npaug ntawm cov yam ntxwv.
Alkyd resin daws yog tus yam ntxwv los ntawm cov hauv qab no tsis:
- viscosity - 35-100 s (raws li VZ-4 viscometer);
- molecular hnyav - 1500-5000 kDa;
- density - 0.9-1.05 g/cm3;
- tus nqi ntawm cov poov tshuaj hydroxide, uas yog lub ntsiab lus qhia ntawm cov roj zoo, tsis ntau tshaj 20.
Raws li qhov kub thiab txias, qhov viscosity ntawm alkyds txo qis thiab rov ua dua. Qhov qis dua cov roj cov ntsiab lus ntawm ib yam khoom, qhov phem dua nws yaj hauv aliphatic thiab naphthenic hydrocarbons.
Txhim kho cov khoom
Unmodified alkyds tsim cov yeeb yaj kiab tawv thiab nkig, yaj tsis zoo. Txhawm rau txhim kho lawv qhov zoo, cov khoom siv ntxiv yog nkag mus rau hauv cov khoom sib xyaw ntawm cov tshuaj tiv thaiv sib xyaw, uas muab cov coatings gloss, elasticity, tsis kam mus rau dej, hnyav, roj thiab huab cua, ua kom qhuav ntawm chav tsev kub, thiab nce adhesion nrog cov khoom siv hauv paus. Hloov kho alkyd resins tau siv linseed, siab roj, tung roj, roj sunflower, castor roj, paj rwb noob roj, rosin, hluavtaws fatty acids.
Muaj 3 txoj hauv kev hloov pauv tseem ceeb:
- qhia txog cov monomers hauv kev tsim khoom;
- by reacting tiav alkyds nrog hloov cov neeg sawv cev;
- sib xyaw resins nrog lwm cov yeeb yaj kiab qub.
Tau txais
Alkyds yog synthesized nyob rau hauv ob txoj kev: alcoholysis thiab fatty acid method.
Hauv thawj kis, cov txheej txheem yuav tshwm sim hauv 3 theem:
- Transesterification ntawm cov roj zaub lossis triglycerides ntawm nws cov fatty acids nrog polyhydric cawv. Cov tshuaj tiv thaiv yuav tshwm sim ntawm qhov kub ntawm 240-260 ° C thiab nyob rau hauv lub xub ntiag ntawm catalyst. Rau kev tsim cov glyphthalic resins los ntawm cawv, glycerin yog siv, rau etrifthalic resins - etriol, rau pentaphthalic resins - pentaerythritol.
-
Esterification ntawm ib nrab esters nrog phthalic anhydride, ua rau muaj kua qaub ester.
- Polyesterification nrog dej tso tawm thiab tsim alkyd.
Txoj kev thib ob rau kev tsim cov resins yog esterification thiab polyesterification ntawm fatty acid esters thiab polyhydric alcohols.
Alkyd nyias nyias
Cov pa roj carbon monoxide hauv qab no ua cov kuab tshuaj rau alkyd resins:
- aliphatic (hexane, heptane, C6-C12 paraffins);
- aromatic (benzene, hnyav, toluene, xylene thiab lwm yam);
- terpene (turpentine);
- halogenated (trichlorethylene, tetrachlorethylene, perchlorethylene);
- roj (nefras, roj av).
Tsawg boiling ethers (ethyl cawv, ethyl acetate), glycol ethers, ketones (acetone) kuj siv tau ua thinners. Butanol tsis tsim nyog rau cov hom phiaj no, vim nws cov molecules nyiam lawv tus kheej ntau ntawm cov kuab tshuaj muaj nyob rau hauv alkyd resins. Lean alkyds yaj tsuas yog nyob rau hauv aromatic hydrocarbons, thaum fatty alkyds yaj nyob rau hauv aliphatic sawv daws yuav.
Tseem muaj cov dej-soluble resins, raws li cov txheej txheem dej los ntawm cov khoom tsim tawm (kub-drying enamels thiab primers).
Daim ntawv thov
Lub hom phiaj tseem ceeb ntawm alkyd resins yog tsim cov xim thiab cov kua roj vanish (LKM). Unmodified compounds yog siv rau kev tsim hluav taws xob insulating varnishes thiab adhesives.
Los ntawmResin daws ua ib nrab thiab tiav cov kua roj vanish siv hauv kev lag luam thiab lub neej txhua hnub.
Cov ntaub ntawv xim
Alkyd txheej yog siv dav tshaj plaws ntawm txhua yam ntaub ntawv raws li polycondensation resins. Txij li thaum pentaerythritol cawv muaj 4 pawg hydroxyl, alkyds muaj pentaerythritol kho sai dua thiab tsim cov txheej txheem glossier. Hauv qhov no, kev lag luam feem ntau tsim cov ntaub ntawv pleev xim raws li alkyd resins ntawm pentaphthalic hom. Kev siv ntau ntawm cov khoom muaj ntxhiab tsw qab ua kom lub zog thiab ua haujlwm ntawm cov txheej txheem rau cov neeg kho tshuab kev nyuaj siab.
Pigmented coatings raws li alkyds tau muab faib ua pawg hauv qab no:
- glyphthalic (GF), pentaphthalic (EF), etrifthalic (ET) enamels;
- soils;
- pawg.
Kev ziab alkyd resins yog siv los ua cov yeeb yaj kiab ywj pheej rau cov xim thiab cov kua roj vanish, thiab cov uas tsis yog ziab yog siv rau hauv formulations nrog carbamide resins, cellulose nitrates (los txhim kho elasticity thiab adhesion ntawm coatings rau cov khoom siv hauv paus).
Cov khoom ntawm txheej yog nyob ntawm lawv cov tshuaj muaj pes tsawg leeg. Yog li, fatter alkyd resins nyob rau hauv cov kuab tshuaj organic yog yooj yim rau siv nrog ib tug txhuam, muaj zog elasticity thiab huab cua tsis kam, tab sis qhuav qeeb qeeb thiab tsis tshua muaj resistant rau ntxhia roj. Qhov siab tshaj plaws ziab tus nqi yog feem ntau rau resins hloov nrog tung los yog linseed.roj. Qhov nruab nrab qhuav-rau-tack lub sij hawm rau alkyd enamels yog 24 teev.
Kev pleev xim tshwj xeeb
Alkyd resins, nyob ntawm seb muaj pes tsawg leeg, yog siv rau cov laj thawj hauv qab no:
- Raws li benzoic acid (cov ntsiab lus roj 38-50% los ntawm qhov hnyav) - enamels rau pleev xim rau cov tshuab ua liaj ua teb, radiators, kho tsheb. Siab ploj mus thiab huab cua resistant.
- Muaj 9,12-linoleic thiab 9,11-linoleic acids - kho khoom siv.
- Skinny - ceev kom qhuav ib lub tsho, primers, radiator xim.
- On linseed roj thiab glycerin - tiv thaiv corrosion, luam ntawv inks. Nws tuaj yeem ploj mus sai sai thaum raug tshav ntuj, yog li lawv feem ntau siv hauv primers thiab leveling compounds.
- Soybean lossis roj siab raws li cov tsho tiv no nrog huab cua zoo.
- Hloov kho nrog cov khoom siv ntuj (rosin acids) - tsim cov primers thiab muab tub lim. Cov tshuaj muaj qhov ua rau ploj mus.
- Hloov kho nrog styrene, acrylate - primers, putties, leveling compounds, coatings rau painting ships, khoom, ntawv hlau, ntoo raug rau cov neeg kho tshuab muaj zog (parquet varnishes, pem teb enamels, rooj tog); ntim cov enamels hauv cov raj. Lawv muaj zog tiv thaiv kev puas tsuaj thiab elasticity.
Ib puag ncig yam
Vim tias alkyd resins muaj cov kuab tshuaj organic, lawv ua rau muaj kev phom sij rau tib neeg kev noj qab haus huv thiab ib puag ncig. Thaum ua cov xim pleev xim thiab cov kua roj vanish siv cov ntaub ntawv pleev xim raws li lawv, nws yog ib qho tsim nyog yuav tsum siv cov khoom siv tiv thaiv tus kheej (cov npog ntsej muag roj, cov npog ntsej muag). Kev pleev xim yuav tsum tau ua hauv chav nrog cov khoom siv thiab tso pa tawm.
Raws li qib toxicity ntawm cov kuab tshuaj, alkyds tuaj yeem muab faib ua 3 pawg:
- yam tshuaj lom (MPC=300-1000 mg/m3) – ethyl ether, cawv, roj av;
- nruab nrab toxicity (MPC=100-200 mg/m 3) - acetone, butyl ether;
- muaj tshuaj lom (MPC=20-50 mg/m3) – ethylene glycol, benzene.
Tshiab, muaj cov kev xav tau siab rau ib puag ncig kev phooj ywg ntawm kev tsim cov txheej txheem, yog li tam sim no, kev ua haujlwm tseem tab tom tsim los tsim cov ntaub ntawv uas muaj cov ntsiab lus siab ntawm cov khoom qhuav thiab cov dej sib xyaw. Txawm li cas los xij, alkyd resins nrog cov kuab tshuaj organic tseem ua tau zoo dua cov dej-soluble resins hauv kev ua haujlwm.
