| UV-curable pastes have many advantages such as energy-save, low volatile organiccompounds, fast cure, easy use, good performace of curing coating and bright colour.UV-curable pastes are low-carbon, environment-friendly and innotive and are widely appliedin wide format advertisement printing, plastic sheets printing, paper printing, floor printing,mental printing, glass printing, printed circuit board printing and optical fibre printing. Buthigh viscosity, bad dispersion stability and slow cure in fabric have limmitted UV-curablepastes in dyeing fabrics.Effects of polyester dispersant and acrylic block copolymer concentrations on pigmentparticle and dispersion, thermal stability and centrifugal stability of the UV-curable pasteswere compared in order to improve dispersion stability of UV-curable pastes. Results showedthat the optimum concentrations of the dispersants were both20%with respect to weight ofpigment. Pigment particle and particle size distribution index of UV-curable pastes were207nm and0.312using polyester dispersant while the pigment particle and particle sizedistribution index of UV-curable pastes were144nm and0.200using acrylic block copolymerdispersant. Centrifugal stabilities of the two UV-curable pastes were both above85%.Pigment particles of UV-curable pastes heated for5days were aggregated to1.89and1.04times of the original ones using polyester dispersant and acrylic block copolymer dispersant,respectively.Compatibility of the components in UV-curable pastes has an important effect onvisicosities. As pigment oligomer ratio was1:1, pigment was well wetted by oligomers.Viscosities were37.8mPa·s and33.0mPa·s as concentrations of acrylic block copolymerdispersant and polyeater dispersant were25%and20%with respect to weight of pigment,repectively. Monomers of EOEOEA, TPGDA and TMPTA had a better compatibility withpigment and oligomer than monomers of LA, DPGDA and PETA. Compatibility ofUV-Curable pastes decreased as the functionality of urethane acrylate increased. Viscosities ofUV-Curable pastes which were made using polyester acrylate or epoxy acrylate were lowerthan those of UV-Curable pastes using urethane acrylate. As ratio of polyeater dispersant andacrylic block copolymer dispersant was2:3, the two dispersants showed most synergisticeffect in pigment dispersion. With the increasement of rheological agent, thixotropy ofUV-curable pastes decreased.Effects of pigment oligomer ratio, oligomers, monomers and photoinitiators on curingspeed of UV-curable pasts applied on cotton are studied. With the increasement of pigmentoligomer ratio and functionality of monomers, curing speeds of UV-curable pastes wereaugmented. Curing speed of epoxy acrylate was faster than those of polyester acrylate andurethane acrylate. The principal absorption wavelengths of photoinitiator819and ITX werelonger than those of photoinitiator1173,907and BP. At the same mass concentration, curingspeeds of819and ITX which had longer principal absorption wavelengths were faster thanthose of photoinitiator1173,907and BP. The curing speeds of photoinitiator819and ITXwere12s and5.0s, respectively, as the concentration of photoinitiator were5%. Curing speed of compound photoinitiaor907and BP was1.2times of photoinitiaor907, while Curingspeed of compound photoinitiaor BP and1173was2.5times of photoinitiator1173. Astemperature increased from15°C to40°C, curing speed was augmented.Influences of UV-curable pastes component to K/S value, wettability, colourfastness tocrocking, colourfastness to laundering and age resistance were investigated. With theincreasement of pigment oligomer ratio, K/S value of dyed cotton was improved, butsaturation and bleeding became worse. As the pigment oligomer ratio was bigger than3:1, dryfastness and colour change became worse. Colour of cotton dyed by UV-curable pastes whichadded urethane acrylate was pure and age resistance of the dyed cotton was also better thanthose of others. Antibleeding of UV-curable pastes added urethane diacylate or Epoxy acrylateusing acrylic block copolymer as dispersant was better than others. As the functionality ofmonomers increased, K/S value of dyed cotton was improved and then declined. Thecolourfastness to crocking, colourfastness to laundering and age resistance were enhancedwith functionality of monomers increasing. However, antibleeding of UV-curable pastes incotton fabric became worse with the increasement of functionality of monomers.Effects of PUA soft segment molecular weight on waterborne UV-curable paste areresearched. As concentration of PUA was13.6%, pigment concentration was6.8%anddispersant concentration was25%with respect to weight of pigment, viscosities ofwaterborne UV-curable pastes were below4mPa.s. With the PUA soft segment molecularweights increasing from400to1000, viscosities were augmented evidently, and particle sizedecreased from95nm to148nm, while particle size distribution became narrow. With theextension of PUA soft segment, centrifugation stability also got worse. The fastness tocrocking of dyed cotton fabric was low, after curing for36s. Wet crocking fastness wasimproved for one grade after curing for60s. The wet crocking fastness and dry crockingfastness of the cotton fabric dyed by UV-curable paste which was made of PUA1000were2-3grade and1-2grade, respectively, after curing for60s. Fastness to laundering of theUV-curable pastes dye cotton fabric was not good. The colour change and colour stain of thecotton fabric dyed by UV-curable pastes which were made of PUA1000were1-2grade and3grade, respectively, after curing for60s. |
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