Direct dyes yog cov dyes uas tuaj yeem ua kom sov thiab rhaub hauv qhov nruab nrab lossis tsis muaj zog qhov nruab nrab yam tsis muaj kev pab los ntawm mordant. Direct dyes yog tsim los ntawm hydrogen bonding van der Waals quab yuam ntawm ncaj dyes thiab paj rwb fibers. Nws yog tsuas yog siv nyob rau hauv fiber ntau, txhob lo lo ntxhuav, paj rwb spinning, tawv thiab lwm yam lag luam, thiab kuj yog siv nyob rau hauv daim ntawv ua thiab lwm yam lag luam. Direct dyes tuaj yeem muab faib ua azo, stilbene thiab lwm hom raws li lawv cov qauv. Raws li lawv daim ntawv thov kev faib tawm, lawv feem ntau suav nrog cov xim ncaj qha ncaj qha, ncaj qha lightfast dyes thiab ncaj azo dyes.
Dye txoj cai
Direct dyes muaj cov dej-soluble pawg xws li sulfonic acid pawg (-SO3H) los yog carboxyl pawg (-COOH) thiab lawv cov qauv molecular yog teem nyob rau hauv ib tug linear duab. Cov qauv nplhaib uas muaj ntxhiab nyob hauv tib lub dav hlau,
Yog li ntawd, cov dyes ncaj qha muaj ntau dua affinity rau cellulose fibers thiab tuaj yeem dyed ncaj qha rau hauv nruab nrab nruab nrab los ntawm tsuas yog dissolving cov dye nyob rau hauv dej qhuav.
Cov dye yog adsorbed rau saum npoo ntawm cov fiber ntau hauv cov tshuaj, thiab tom qab ntawd txuas ntxiv mus rau thaj tsam amorphous ntawm cov fiber ntau, tsim kev sib xyaw ntawm hydrogen bonds thiab van der Waals rog nrog cov fiber ntau macromolecules.
Derived dyes muaj xws li direct lightfast dyes thiab ncaj tooj liab ntsev dyes.
Dye yam ntxwv
Direct dyes muaj cov dej-soluble pawg xws li -SO3Na thiab -COONa. Lub solubility nce ho nrog qhov nce ntawm qhov kub thiab txias. Rau cov dyes ncaj qha nrog tsis zoo solubility, soda tshauv tuaj yeem ntxiv los pab yaj. Cov dyes ncaj qha tsis tiv taus cov dej tawv thiab feem ntau tuaj yeem ua ke nrog calcium thiab magnesium ions los ua cov xim tsis muaj kuab lom.
Direct dye ntau lawm txheej txheem
Cov dej nag ua rau cov stains ntawm cov ntaub dyed, yog li cov dyes ncaj qha yuav tsum tau yaj hauv dej mos. Yog hais tias lub hardness ntawm dyeing dej siv nyob rau hauv ntau lawm yog siab, soda tshauv los yog sodium hexametaphosphate ntxiv, uas yuav tsis tsuas pab yaj cov dye, tab sis kuj soften cov dej.
Direct dyes yog ncaj qha rau cellulose fibers dua li lwm cov dyes. Qhov no feem ntau yog vim qhov hnyav molecular ntawm cov xim ncaj qha, cov qauv kab molecular, zoo symmetry, ntev conjugated system, zoo co-planarity, thiab loj van der Waals rog ntawm dye thiab fiber ntau molecules. Nyob rau tib lub sijhawm, cov tshuaj zas ncaj qha muaj cov amino, hydroxyl, azo thiab lwm pab pawg, uas tuaj yeem tsim hydrogen bonds nrog hydroxyl pawg hauv cellulose fibers thiab hydroxyl pawg thiab cov amino pawg hauv cov protein fibers, ntxiv txhim kho qhov ncaj qha ntawm cov xim.
Thaum cov dyes ncaj qha siv los dye cellulose fibers, ntsev plays lub luag hauj lwm dye-txhim kho. Lub dyeing txhawb mechanism yog hais tias ncaj qha dyes dissociate rau pigment anions nyob rau hauv cov tshuaj thiab dye cellulose fibers. Cellulose fibers kuj muaj cov nqi tsis zoo hauv dej. Muaj cov nqi repulsion ntawm dyes thiab fibers. Ntxiv ntsev rau cov tshuaj zas xim tuaj yeem txo tus nqi. Repulsive quab yuam nce tus nqi dyeing thiab dyeing feem pua. Cov tshuaj zas ncaj qha sib txawv muaj qhov sib txawv dye-txhim teebmeem. Salt-effect ncaj dyes nrog ntau sulfonic acid pawg nyob rau hauv lub molecule muaj ib tug tseem ceeb dye-txhim nyhuv. Thaum dyeing, ntsev yuav tsum tau ntxiv rau hauv cov khoom siv kom ntseeg tau tias cov xim zoo ib yam. Direct dyes nrog qis dye uptake feem pua yuav tsum tau ntxiv ntsev ntxiv, thiab cov nyiaj tshwj xeeb tuaj yeem txiav txim siab raws li hom dyeing thiab dyeing qhov tob. Rau cov khoom siv xim xim nrog cov kev xav tau dyeing siab, cov ntsev yuav tsum raug txo kom tsim nyog kom tsis txhob muaj qhov sib npaug hauv zos dyeing thiab dyeing defects xws li xim paj.
Cov nyhuv kub
Cov nyhuv ntawm qhov kub thiab txias ntawm cov khoom dyeing ntawm cov xim sib txawv yog txawv. Rau cov dyes ncaj qha nrog tus nqi dyeing siab thiab kev ua haujlwm zoo, cov xim tob tshaj plaws tau txais ntawm 60-70 degree , thiab tus nqi dyeing qis dua 90 degree . Thaum dyeing hom dyeing no, txhawm rau txo lub sijhawm dyeing, qhov kub ntawm dyeing yog 80-90 degree . Tom qab dyeing rau ib lub sij hawm, qhov kub ntawm cov tshuaj zas xim maj mam txo, thiab cov dyeing nyob rau hauv cov tshuaj zas xim tseem mus zas cov fibers kom cov dye uptake feem pua. Rau cov dyes ncaj qha nrog cov qib siab ntawm kev sib sau ua ke, qeeb dyeing tus nqi thiab kev ua haujlwm tsis zoo, ua kom qhov kub thiab txias tuaj yeem ua kom cov dyeing diffusion, nce tus nqi dyeing, thiab txhawb qhov qaug zog ntawm cov dyeing hauv cov dyeing cawv, nce qhov feem pua dyeing. Tsis pub dhau lub sij hawm dyeing cov pa, qhov kub ntawm qhov siab tshaj plaws dye uptake feem pua yog hu ua qhov siab tshaj plaws dye uptake kub. Raws li qhov sib txawv ntawm qhov siab tshaj plaws dyeing kub, cov dyes ncaj qha feem ntau muab faib ua qhov kub thiab txias nrog qhov siab tshaj plaws dyeing kub hauv qab 70 degree, nruab nrab kub dyes nrog qhov siab tshaj plaws dyeing kub ntawm 70-80 degree, thiab dyes nrog qhov siab tshaj plaws. dyeing kub ntawm 90-100 degree . Kub kub dyes. Hauv kev xyaum ntau lawm, paj rwb thiab viscose fiber ntau knitted fabrics feem ntau yog dyed nyob ib ncig ntawm 95 degree, thaum silk knitted fabrics yog dyed ntawm qhov kub thiab txias vim hais tias kub heev ua rau cov fiber ntau. Qhov zoo tshaj plaws dyeing kub yog 60 txog 90 degree. Kev txo qis qhov kub ntawm dyeing kom raug thiab ncua sij hawm dyeing yog qhov zoo rau kev tsim khoom.