A Research On The Preparation And Performance Of Core-shell Silicon-acrylate Emulsion Adhesive For Printing

In China, although polyacrylate the most widely used for printing adhesives right now,there are so many disadvantages to prevent improving printing quality, such as the poor waterresistance, intolerance contamination, easy broken when it is cool and sticky when it is hot,containing the N-methylol acrylamide, as well as releasing formaldehyde during baking andstoring. As a result, it’s still a current situation that high-class printing textiles need to beimported. In order to solve above problems, this subject will conduct a research thatorganosilicon, whose properties includes soft, hydrophobic, low viscosity and low surfacetension, modifies the acrylate emulsion and prepare a kind of core-shell silicon-acrylateemulsion as adhesive which will be applied into pigment printing of the cotton fabric.Core-shell silicon-acrylate emulsion can be prepared by using semi-continuous seededemulsion polymerization, butyl acrylate (BA) and methyl methacrylate (MMA) as rawmaterials, acrylic acid (AA) as functional monomer, vinyl trimethoxysilane (A-171) asmodifier. The optimum synthesis conditions is: a core-shell mass radio of1:2, nuclear layermBA: mMMA=1:1, shell layer mBA: mMMA=3:1, reaction temperature80℃,1hour thermostaticreaction time, compound emulsifiers mSDS: mOP-10=2:3, which is3%of the momomer massfraction as same as below,1.2%of initiator,4%of A-171,0.3%of AA,0.5%of buffer. Thus,the reaction conversion ratio of the silicon-acrylate emulsion, gelation rate, water absorption,water contact angle is95.01%,0.56%,10.34%and63.83°respectively. In the aspect of heat,cold and water, silicon-acrylate emulsion is much better than core-shell and non-core-shellone.The analysis of infrared spectroscopy (IR) shows that the organosilicon can have acopolymerization with acrylate monomers, no hydrolysis or self-polymerization. Besides, theanalysis result of transmission electron microscopy (TEM) indicates that silicon-acrylate latexparticles have a core-shell structure, whose size is uniform and in the range of128nm. Thescanning electron microscopy (SEM) visualizes that the surface of silicon-acrylate film issmooth without break. X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS)test that the silicon is enriched on the surface of film and forms self-stratification, whichmakes the water absorption of silicon-acrylate film is only account for34%of pure acrylatefilms. Differential scanning calorimetry (DSC) analyzes that silicon-acrylate film only hasone glass-transition temperature-13.83℃, which is basically matched with theoretical value-15.60℃, and a harmonious nuclear shell compatibility without phrase separation. Thermalgravimetric (TG) shows that the thermal decomposition temperature of silicon-acrylate film is 16℃higher than pure acrylate, which indicates that silicon-acrylate film has a better hightemperature resistance.Applying the core-shell silicon-acrylate emulsion into the pigment printing, under thecondition of5%of paint (representing the percentage of paste as same as below),20%adhesive,2%thickener and baking temperature150℃in3minutes, the printed textileacquires the best situation that the grade of dry rubbing fastness, soaping fastness can reach4-5,3-4grade of wet rubbing fastness, chromaticity value59.87, bending rigidity2.13cN·mm-1. On the other hand, the static and dynamic friction coefficients is0.625and0.413respectively. Compared with the pure acrylate emulsions and adhesive products,silicon-acrylate emulsion printing has a secure color fastness, deep tone and high colorsaturation. In addition, the advantages also include soften, smooth, non-sticky andnon-blocking. In all, it is a good to be widely used its excellent comprehensive applicationperformance in pigment printing area.