| Ink-jet printing of pigment inks has the advantages of simple process,general applicability,energy-saving,and emission reduction,which displays great potential in the field of ink-jet printing.However,pigment particles are fixed on the fabrics by film formation of the adhesive due to the lack of interaction force between pigment and the fabrics.Poor film-forming of the adhesive will result in the shedding of pigment particles and poor color fastness of the ink-jet printed fabrics.Meanwhile,the dispersant of the pigment ink is prone to desorption or"bridging"during usage and storage,leading to agglomeration of pigment particles and clogging the nozzle.In addition,demulsification and deformation of the adhesive latex particles in pigment inks will cause serious degradation of the stability and ejection performance of the ink.The above problems will affect the quality of pigment ink ink-jet printing and limit its application.In this research,anthraquinone-type dyes with olefinic double bonds were designed and synthesized as coloring monomers,and then copolymerized with acrylic monomers and crosslinked silicone monomers via emulsion polymerization to prepare the self-crosslinking colored latex particles integrating the functions of coloring and film formation.The relationship between the glass transition temperature and its filtering performance was studied.In order to improve the jetting performance of the color latex particles,core-shell color latex particles with a structure composed of a“soft”core and a"hard"shell were obtained by encapsulating the self-crosslinking color latex particles with polystyrene.Finally,to further improve the dispersion stability and color depth of the color latex inks,the reactive dyes with water-soluble groups were grafted onto the surface of the latex particles,and colored latex particles with self-dispersing properties were prepared.The specific research contents are as follows:(1)Three anthraquinone-type dyes with olefinic double bonds were designed and synthesized,showing different shades of red(?max=503 nm),yellow(?max=407 nm),and blue(?max=647 nm),respectively.The structure and properties of synthetic dyes were characterized.The results of FT-IR,1H-NMR,and elemental analysis showed that the anthraquinone-type dyes with olefinic double bonds have been successfully synthesized.Their yields were 85%,83%,and 81%,and the melting points were 173.8-174.2?,158.2-159.3?,and 160.3-161.1?respectively.The results showed that the introduction of linking groups(alkyl chain)can effectively decrease the effect of polymerizable groups on the electron cloud density of dye chromophores,and reduce the blue shift of the maximum absorption wavelength after polymerization.Meanwhile,the solubility of the dyes in the mixed monomer solution of styrene and n-butyl acrylate increased from 0.45 g/L to 3.75 g/L after the introduction of the linking groups.The test results of the free radical capture and scavenging ability of the dyes showed that the free radical scavenging ability of the dye was small(<12%),which can ensure that the dye monomer can successfully copolymerization initiated by the initiator.This research provides a polymerizable colorant monomer with excellent performance for the preparation of colored latex particles.(2)Self-crosslinking colored latex particles were prepared via emulsion polymerization by using anthraquinone-type dyes with olefinic double bonds as the colorant monomer,vinyl trimethoxysilane(VTMS)as the crosslinking monomer,styrene as the hard monomer,and n-butyl acrylate as the soft monomer.The results showed that the self-crosslinking colored latex particles were uniform and spherical morphology with an average diameter of 70 nm.The physical properties of the latex film can be adjusted by adjusting the amount of VTMS,which affected the crosslinking density of the latex film.When the amount of VTMS increased from0 wt%to 4 wt%,the tensile elongation yield of the latex film increased from 309%to 563%.The color fastness to rubbing and washing of self-crosslinking colored latex particle printed fabrics can reach 4-5 grades or above.Then the pigment ink was prepared by self-crosslinking colored latex particles,and the filtering performance was explored.When the glass transition temperature(Tg)of the particles was 24?,the particles were prone to deformation,film formation,and blockage of the pores.When the Tg was 38?,the filtering performance of the inks was slightly improved with an increase of the filtering time and still blocked.When the Tgwas greater than 48?,the particles can keep the shape during the filtration with no deformation and film-forming.However,the increasing Tg of particles will cause the decrease of the tensile elongation yield of the latex film,resulting in the poor color fastness,and hard hand feel of ink-jet printed fabrics.(3)To improve the filtering performance of the colored latex inks while retaining the soft and tough characteristics of the latex film,polystyrene was encapsulated on the surface of the self-crosslinking colored latex particles(Tg=30?)with three different colors of red,yellow,and blue to prepare the core-shell colored latex particles with uniform size and spherical shape by seed emulsion polymerization.The shell thicknesses of the core-shell color latex particles can be adjusted by adjusting the amount of styrene and initiator.When the shell thicknesses were 20,25,and 22 nm,the inks can smoothly pass through the filter membrane and the flow rates were 8.9,7.2,and 9.1 m L/s,respectively.But the hand feel of ink-jet printed fabrics turned hard with the increase of shell thicknesses.The core-shell color latex ink was used for textile ink-jet printing,and the ink-jet printed fabrics had a good color fastness reaching 4 grades or above and a softer hand feel than commercial pigment ink inkjet printed fabrics.(4)To further improve the stability of color latex inks,reactive dyes containing water-soluble groups were grafted onto the surface of aminated latex particles to prepare self-dispersing color latex particles(PGMA-NH-X-3B)with a particle size of 200 nm and a spherical monodispersed distribution.The water-soluble groups in the structure of PGMA-NH-X-3B can provide good self-dispersing properties.The thermal stability,centrifugal stability,and storage stability of the self-dispersing colored latex particles can reach 90%,93%,and96%,respectively.Meanwhile,the dispersion will not settle when stored at room temperature for half a year.The PGMA-NH-X-3B ink can quickly pass through the filter membrane with a flow rate of 5.8 m L/s.The color fastness of inkjet printed fabrics was 5 grade,and the hand feel of the printed fabrics was also soft. |
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