Cov teeb meem uas yuav tsum tau them sai sai rau thaum xaiv thiab siv optical brighteners hauv cov txheej txheem papermaking

Cov teeb meem uas should yuav tsum tau them sai sai rau thaum xaiv thiab siv optical brighteners hauv ptxheej txheem apermaking
 1. dej
Dej yog qhov tseem ceeb rau kev tsim cov ntawv thiab pulping. Tshwj xeeb, cov ntaub ntawv ntub dej siv dej ntau heev. Txhawm rau tsim cov ntawv siab dawb, cov tshuaj fluorescent whitening yuav tsum tau ntxiv thaum lub sijhawm ua ntawv. Lub sijhawm no, kev saib xyuas tshwj xeeb yuav tsum tau them rau qhov nyuaj ntawm cov dej thiab cov kua qaub hauv dej. , kev cuam tshuam ntawm cov ntsiab lus ntawm cov tshuaj dawb chlorine thiab hnyav hlau ions, xws li hlau, tooj liab, manganese, thiab lwm yam ntawm cov nyhuv whitening.
Thaum lub sij hawm txheej txheem ntawm dissolving thiab siv kho qhov muag brighteners, koj yuav tsum sim kom tsis txhob sib cuag nrog hnyav hlau ions xws li hlau thiab tooj liab. Nws yog qhov zoo tshaj plaws los siv cov thawv inert xws li yas lossis stainless hlau. Yog tias cov ntim khoom siv tsis tuaj yeem siv, khaws qhov kev ncua deb ntawm cov tshuaj kho qhov muag brightener thiab cov khoom siv hlau kom luv li sai tau. tiv tauj lub sij hawm los tiv thaiv nag lossis daus ntawm hlau ntsev.
Muaj cov kev xav sib txawv ntawm qhov cuam tshuam ntawm dej hardness ntawm cov nyhuv whitening ntawm optical brighteners. Cov dej tawv tuaj yeem ua rau cov nyhuv whitening ntawm qee qhov kho qhov muag ci ntsa iab (piv txwv li, nws muaj txiaj ntsig zoo los txhawb kev dyeing), tab sis qee zaum nws yuav ua rau cov nyhuv whitening. , nyob rau lub sijhawm no, cov dej muag muag yuav tsum tau siv los ua kom cov fluorescent whitening agent ib leeg, thiab sim siv cov dej uas tsis tshua muaj hardness lossis softened dej.
Rau cov dej dawb rov siv dua, cov txhuas ions hauv nws yuav tsum tau kho kom zoo. Thaum rov siv cov dej dawb, nws raug nquahu kom ua ntej kho tus nqi pH kom ze rau qhov nruab nrab. Txij li thaum rov siv cov dej dawb tuaj yeem yooj yim ua rau cov hlau hnyav hnyav, nws feem ntau zoo dua los siv tetrasulfonic acid-based fluorescent whitening agents.
2. Basic whiteness ntawm pulp
Txij li cov xim dawb ntawm fluorescent whitening agents yog ib qho kev sib txuas ntawm cov xim zoo nkauj, nws tsis cuam tshuam rau cov tawv nqaij.
Nws muaj cov nyhuv bleaching thiab tsis tuaj yeem hloov cov tshuaj bleaching rau bleach pulp. Yog li ntawd, rau cov tawv nqaij uas muaj ntau ntawm lignin thiab lwm yam xim, yog tias nws yog whitened ncaj qha nrog fluorescent whitening tus neeg saib xyuas yam tsis muaj bleaching, txaus siab yuav tsis tau.
Kuj tseem muaj cov kev ntsuam xyuas uas ua pov thawj tias cov xim dawb ntawm cov tawv nqaij uas nws cov xim dawb yog ntau dua 80% ntawm cov qauv kev ua kom dawb ntawm cov ntawv luam ntawv tuaj yeem ncav cuag ntau dua 95% ntawm cov qauv dawb thaum ua kom dawb nrog fluorescent whitening agent. Txawm li cas los xij, nws yog ib qho nyuaj rau daim ntawv uas muaj cov xim dawb kom mus txog rau theem saum toj no txawm tias cov tshuaj fluorescent whitening ntau ntxiv.
3. Cov tshuaj rau kev ua ntawv
Nrog rau kev zam ntawm cov khoom cationic, ob peb cov tshuaj nquag siv hauv papermaking muaj qhov cuam tshuam rau kev ua kom dawb. Kev saib xyuas tshwj xeeb yuav tsum tau them rau qhov tseeb tias yog tias muaj cationic additives nyob rau hauv lub pulp, lawv yuav ua ke nrog anionic fluorescent whitening tus neeg sawv cev los tsim ib qho kev sib tov tsis sib haum, uas yuav cuam tshuam rau cov nyhuv whitening. Yog li ntawd, thaum siv, xyuam xim rau qhov kev txiav txim ntawm kev ntxiv cationic additives thiab xaiv qhov tsim nyog ntxiv cov ntsiab lus kom txo los yog tshem tawm qhov cuam tshuam.
Cationic ntub dej txhim kho, tshwj xeeb tshaj yog cov khoom siv polyethyleneimine, ib qho me me ntawm urea-formaldehyde thiab melamine-formaldehyde cov khoom, kuj muaj kev cuam tshuam tsis zoo rau qee qhov muag pom kev.
4. Ntim
Cov khoom sib txawv ntawm qhov muag pom kev sib txawv, vim lawv cov qauv tshuaj sib txawv, muaj qhov sib txawv rau cov khoom ntim xws li silicates feem ntau siv hauv kev lag luam ntawv, xws li kaolin, titanium dioxide thiab talc. Feem ntau, txawm li cas los xij, cov fillers no muaj xim daj thiab cov fillers tuaj yeem tsuas yog whitened rau qee yam. Ntxiv cov fillers rau bleached thiab whitened cov ntaub ntawv feem ntau ua rau ib tug maub whiteness, raws li cov fillers feem ntau yog daj nyob rau hauv cov xim tshaj bleached cellulose pulp. Txhawm rau muab kev ua si tag nrho rau cov nyhuv ntawm fluorescent whitening agent, cov muab tub lim xaiv yuav tsum yog dawb li sai tau. Titanium dioxide absorbs nyob rau hauv lub UV ntau yam, thiab rutile hom absorbs ntau zog tshaj li hom anatase. Yog li ntawd, rutile tsis haum raws li ib tug muab tub lim thaum siv optical brighteners. Calcium silicate thiab magnesium silicate fillers muaj qhov cuam tshuam tsawg kawg nkaus ntawm cov teeb pom kev zoo.
5. Xaiv cov fluorescent whitening agents scientifically thiab rationally
Yog hais tias cov ntsiab lus saum toj no yog lub hauv paus rau tus neeg sawv cev fluorescent whitening ua hauj lwm, ces xaiv cov fluorescent whitening tus neeg sawv cev uas tsim nyog raws li cov khoom siv pulp yog qhov yuav tsum tau ua ua ntej rau kev siv scientific thiab tsim nyog siv fluorescent whitening agent. Ua ntej siv, ib qho qauv me me feem ntau yuav tsum tau ua kom txiav txim siab Hom, ntau npaum li cas thiab cov txheej txheem zoo ntawm cov tshuaj fluorescent whitening agent.
Kev lag luam papermaking feem ntau siv anionic dej-soluble fluorescent whitening agents, thiab feem ntau ntawm lawv yog 4,4 'diaminostilbene 2,2' disulfonic acid (DSD acid) sodium ntsev, ammonium ntsev los yog poov tshuaj ntsev. Nws muaj ib tug natural affinity thiab yuav adsorbed rau fibers.
DSD acid bistriazine fluorescent whitening agents muaj cov khoom sib txawv nyob ntawm seb muaj pes tsawg tus sulfonic acid pawg uas lawv muaj, tab sis kuj tseem muaj qee cov kev cai, uas tuaj yeem ua tiav raws li hauv qab no:
(1) Cov pab pawg sulfonic acid ntau dua, qhov me dua qhov kev sib raug zoo rau cov nqaij fibers.
(2) Cov pab pawg sulfonic acid ntau dua, cov cationic polymer tsawg dua.
(3) Cov hom disulfonic acid-raws li yog tsim rau siv nyob rau hauv nruab nrab los yog tsis muaj zog alkaline tej yam kev mob, thiab tetrasulfonic acid-raws li thiab hexasulfonic acid-raws li ntau yam yog haum rau siv nyob rau hauv weakly acidic tej yam kev mob.
(4) Cov pab pawg sulfonic acid ntau dua, qhov cuam tshuam tsawg dua nws yuav yog los ntawm cov hlau hnyav ions.
6. Tus nqi ntawm fluorescent whitening tus neeg sawv cev thiab lub yellowing point
Qhov ntau npaum ntawm optical brightener feem ntau yog qhia raws li feem pua ​​(%) txheeb ze rau qhov hnyav ntawm cov tawv nqaij qhuav kiag li. Cov nyhuv whitening ntawm fluorescent whitening agents ntawm daim ntawv pulp txawv nyob ntawm seb qhov ntau npaum li cas. Cov "daj me ntsis" ntawm whiteners.
  Cov ntsiab lus daj tau hais los saum toj no yog ib qho ntawm cov tshuaj fluorescent whitening agents, thiab cov fluorescent whitening agents muaj cov ntsiab lus daj sib txawv.Yog li ntawd, ua ntej siv cov tshuaj fluorescent whitening agents, koj yuav tsum ua ib qho kev sim me me ua ntej los txiav txim qhov kev pom zoo, thiab tom qab ntawd tswj cov tshuaj hauv qab "daj point" raws li xav tau, thiaj li tau txais txiaj ntsig zoo tshaj plaws thiab cov txiaj ntsig kev lag luam. Txwv tsis pub, nws yuav tsis tsuas yog ua rau nws khib nyiab thiab tsis tuaj yeem tau txais txiaj ntsig zoo. Qee lub sij hawm siv cov tshuaj fluorescent whitening ntau dua, qhov kev ua kom dawb yuav ua rau tsis zoo, thiab tus neeg siv tsis tuaj yeem paub qhov teeb meem. Papermaking cov neeg ua haujlwm yuav tsum tau saib xyuas tshwj xeeb rau qhov no.
7. Cov nyhuv pH
Cov nyhuv whitening ntawm optical brighteners hloov nrog tus nqi pH, thiab qib ntawm kev hloov pauv txawv nrog ntau hom optical brighteners. Ntau lub tshuab kho qhov muag muaj qhov ua kom zoo nkauj zoo nkauj ntawm pH=6 txog 8, tab sis kuj muaj cov nyhuv whitening tsawg ntawm pH=4 txog 4.5.
Tus nqi pH muaj txiaj ntsig zoo rau kev ua kom zoo nkauj ntawm qee cov tshuaj fluorescent whitening agents. Tshwj xeeb tshaj yog nyob rau hauv acidic sizing, thiaj li yuav tau txais qhov zoo tshaj plaws cov nyhuv, pH ntawm daim ntawv Tshuag nyob rau hauv net los yog cov dej dawb nyob rau hauv lub net yog feem ntau tswj=4. 5 ~ 6, uas muaj cov kua qaub tsis zoo. Rau cov tshuaj fluorescent whitening agents, thaum pH tus nqi ntawm cov slurry qis dua 5.5, cov tshuaj fluorescent whitening agents ua turbid los yog tsim floc, thiab cov nyhuv whitening yuav ua phem. Yog li ntawd, yuav tsum tau saib xyuas rau kev siv cov tshuaj fluorescent whitening agents nyob rau lub sijhawm no. Ntxiv qhov chaw (kev txiav txim ntxiv) thiab kho cov pH ntawm slurry.
Raws li kev paub ntau lawm, fluorescent whitening cov neeg ua haujlwm nrog cov kua qaub tsis zoo tuaj yeem ua tiav cov nyhuv whitening tseem ceeb thaum siv nyob rau hauv nruab nrab lossis me ntsis alkaline. Cov nyhuv whitening txo qis thaum pH =6 lossis qis dua.
8. Ntxiv ib ntus
Feem ntau, cov tshuaj aqueous ntawm fluorescent whitening tus neeg saib xyuas tsis muaj zog alkaline, nrog tus nqi pH ntawm 8 mus rau 9. Thaum ntsib txhuas sulfate, cov dej dawb lossis lub teeb daj-insoluble txhuas / fluorescent whitening tus neeg sawv cev flocculent precipitate yuav tsim, thiab cov khoom yuav raug tsim. ua loj. Lub conical slag tshem tawm nyob rau hauv lub rear seem yog tawm ntawm lub system, uas yuav txo tau cov tuav ntawm lub fluorescent whitening tus neeg saib xyuas thiab cuam tshuam rau cov nyhuv whitening. Yog li ntawd, thaum lub sij hawm sizing, tus neeg sawv cev fluorescent whitening tsis tuaj yeem muab ntxiv rau tib lub sijhawm li txhuas sulfate. Feem ntau cov fluorescent whitening tus neeg sawv cev yuav tsum tau ntxiv ua ntej lwm cov ntaub ntawv pabcuam, kom nws tuaj yeem sib npaug thiab khov kho nrog cov fibers thiab khaws cia, thiab tom qab ntawd lwm cov ntaub ntawv pabcuam tuaj yeem muab ntxiv. Lub sijhawm luv ntawm kev ntxiv cov tshuaj tua kab mob fluorescent thiab lwm yam khoom siv pabcuam yuav tsum tsis pub tsawg dua 10 feeb, thiab yog tias muaj kev tso cai, ncua nws mus rau ntau tshaj 20 feeb yuav muab cov txiaj ntsig zoo dua. Optical brighteners uas tau nqus tag rau hauv cov ntawv fibers tsis cuam tshuam thiab lawv cov nyhuv whitening tsis tuaj yeem cuam tshuam txawm tias muaj ntau tshaj txhuas.
9. Lub teeb
Txij li tag nrho cov fluorescent whitening agents siv hauv papermaking muaj cov qauv stilbene, fluorescent whitening agents nrog cov qauv stilbene yuav tsim cis-trans isomerism nyob rau hauv qhov kev txiav txim ntawm lub teeb (xws li lub teeb txaus ultraviolet).
Phem. Nyob rau hauv tshav ntuj, nws yuav hloov los ntawm cov fluorescent heev trans qauv mus rau lub non-fluorescent cis qauv, thiab qhov no cis-trans isomerization hloov ua ib qho tseem ceeb vim hais tias cov concentration ntawm cov fluorescent whitening neeg sawv cev aqueous tov txo, yog li cuam tshuam rau cov nyhuv whitening. , yog li cov tshuaj fluorescent whitening agent yuav tsum tau ceev kom deb ntawm tshav ntuj thiab muab cia rau hauv qhov chaw tsaus.