Preparation,Film-formation Properties And Coloring Mechanism Of Fluorosilicone-modified Polymer/Pigment Hybrid Latex Via One-pot Polymerization

In the traditional textile industry,chemical dyes and pigments are extensively used to achieve various colors,which improves the quality and grade of textiles.Compared with the dye dyeing with high water consumption,high energy consumption,and high pollution,pigment coloring has the characteristics of innocuity,energy saving,water saving,and emission reduction,which is more in line with the low-carbon green development direction of the textile field.However,a large number of binders are needed to make pigment firmly adhere to fabric,due to the poor dispersion stability of pigment in water and the lack of binding force between pigment and fabric.This method not only reduces the rubbing fastness,but also leads to poor air-permeability and stiff hand-feeling of colored fabric.Therefore,the development of high-performance pigment coloring technology is one of the important topics in the field of green and low carbon dyeing and finishing.Polyacrylate is one of the most popular binders with excellent performance,such as low cost,high transparency and good luster.However,there are shortcomings in heat adhesion and cold brittleness.The hydrophobic and smooth properties of the copolymer latex film can be improved by introducing high flexible fluorosilicone chains into polyacrylate latex.A large amount of fluorosilicone leads to the decrease of mechanical properties and friction resistance of the latex film.It is reported that the mechanical strength,water resistance,and friction resistance of the latex film can be improved through the moderate cross-linking network structure formed in the latex film.In this paper,a series of high-performance cross-linked fluorosilicone-modified polyacrylate/pigment hybrid latex are designed and prepared by one-pot method,which combines ring-opening polymerization of fluorosilicone ring monomer and free radical polymerization of acrylate,uses vinyl silane coupling agent as bridging agent,introducing fluorosilicone polymer segments into polyacrylate main chain in situ,and encapsulates the organic pigment particles.Overcoming the practical problem of poor coloring effect of traditional binder-pigment blended color-paste.We have established a one-pot in situ copolymerization hybrid system and improved the color of pigment-colored fabrics.The specific research contents are as follows:（1）Preparation and coloring properties of anionic self-crosslinked fluorosilicone-modified polymer/pigment hybrid latexUsing methyl methacrylate（MMA）,butyl acrylate（BA）,octamethyl cyclotetrasiloxane（D₄）,1,3,5-Tris（3,3,3-trifluoropropyl）-1,3,5-trimethylcyclotrisiloxane（D₃F）as comonomers,3-（trimethoxysilyl）propyl methacrylate（MPS）or 3-[dimethoxy（methyl）silyl]propyl methacrylate（KH571）as bridging,the organic pigment particles are encapsulated by one-pot in situ polymerization,and the anionic self-cross-linked fluorosilicone-modified polymer/pigment hybrid latex is obtained.The influence of comonomer composition（the ratio of D₄ to D₃F,（D₄+D₃F）to（MMA+BA））,silane coupling agent content and type,and pigment content and type on the stability of hybrid latex are investigated.The results show that stable dispersive polymer/pigment hybrid latex with typical core-shell structure is successfully prepared.The fluorosilicone chain segment reduces the glass transition temperature（T_g）and improves the mechanical properties of the hybrid film.Compared with the traditional printed PET fabric,the binder-free polymer/pigment hybrid latex printed PET fabric has better color depth,rubbing fastness,air-permeability and softness.This is attributed to the high flexibility of the fluorosilicone chain segment,which makes the movement of the polymer molecular chain easier.A significant transformation has been achieved from the traditional coloring in the form of thick continuous film to the hybrid film on the fabric surface of discontinuous film and single yarn coating.（2）Preparation and dyeing properties of cationic self-crosslinked fluorosilicone modified polymer/pigment hybrid latexIn order to develop a new type of self-adhesive hybrid latex for continuous rolling dyeing of cotton fabrics,a series of cationic polymer/pigment hybrid emulsions are prepared by using potassium hydroxide（KOH）as catalyst for the ring-opening of fluorosilica-ring monomer and using hexadecyltrimethyl ammonium bromide（CTAB）as cationic emulsifier to enhance the driving force of the hybrid latex on cotton fibers.The results show that a cationic self-crosslinked fluorosilicone modified polymer/pigment hybrid latex with good colloidal stability is prepared by ring-opening polymerization catalyzed by 1 g/L KOH and the conversion rate of organic fluorosilicone emulsion is87.2%.Compared with the study on the properties of traditional dyed cotton fabrics,it is found that the synthetic cationic hybrid latex dyed cotton fabric has higher color depth,retains the pores between yarns,and has similar air permeability and hand-feeling to the original cotton fabric,which significantly improves the wear performance of the pigment dyed cotton fabric.（3）The effect of crosslinking degree on film formation of fluorosilica-modified polymer/pigment hybrid latex and film formation mechanismBased on the above results,a series of fluorosilicone-modified polymer/pigment hybrid latex with different crosslinking degrees are synthesized by regulating the hydrolyzed siloxane group in the bridging agent,to further explore the discontinuous film formation and single yarn coating mechanism of self-crosslinked polymer/pigment hybrid latex.The drying process of hybrid latex is investigated.The surface and bulk microstructure of hybrid latex film are analyzed.The relationship between film forming properties,film microstructure and fabric coloring properties are established.With the increase of crosslinking degree of hybrid latex,more water as a plasticizer in the film forming process and the high flexibility of the fluorosilicone chain segment makes the polymer chain easier to move,and reduced the T_g of hybrid latex.At the same time,the moderate crosslinking structure（gel ratio of 43.0 wt%）limits the interdiffusion of polymer chains,decreases the Peclét（Pe）number from 12.2 to 4.7,increases the diffusion rate of latex particles,slows down the trend of skin formation,and improves the viscous flow ability,rapid dispersion and redistribution of latex particles in the printing process.Therefore,the hybrid latex exhibits discontinuous film formation on the fabric surface and single yarn wrapping,and improves the color depth,rubbing fastness,softness and air-permeability of the hybrid latex printed fabric.In short,the self-crosslinked fluorosilicone-modified polymer/pigment hybrid latex with good dispersion stability is developed by one-pot double in situ miniemulsion polymerization.The motion state of the self-crosslinked fluorosilicone-modified polymer/pigment hybrid latex in the film forming process is clarified.The mechanism of the hybrid film’s discontinuous covering of fabric surface and wrapping of single yarn is revealed.A new dyeing technology of textile coatings is developed,which provides method guidance and theoretical basis for green and low-carbon dyeing technology of textile coatings.