Study On Modified Acrylate Latex Pressure-sensitive Adhesive

Waterborne acrylate latex pressure-sensitive adhesive (PSA) has been used in theautomotive, aerospace, electronic appliances and other fields for its no toxic, environmentalfriendly, low cost and good adhesive properties. However, Chinese brands basically do notinvolve in these areas for its poor adhesion strength, low solid content and poor hightemperature resistance, so the acrylate latex PSA needs to be modified to meet therequirements of industrial applications.In this paper, a kind of cross-linker modified acrylate latex PSA was prepared by usingdodecanethiol as chain transfer agent, N-methylol acrylamide (N-MAM) as internalcross-linker, isocyanate (GH) as the external cross-linker, the modified water-basedpolyacrylic PSAs were prepared by semi-batch emulsion polymerization. The effects of CTA,N-MAM and GH on the properties of modified latexes adhesive were investigated. Then akind of acrylate latex PSA was modified by polyurethane (PU) was synthesized. The effectsof PU content on the properties of PU-acrylic hybrid PSA (PUA) latexes, statu and dynamicmechanic analysis, adhesive properties and heat resistance were studied. Finaly, the effects ofthe contents of emulsifier, CTA, acrylic acid (AA), hydrogenated rosin (HR) and PU on thesurface tension of modified acrylate latexes PSA were studied, and bonding mechanics wasalso studied. The properties of the acrylate latexes PSA were characterized by malvern laserparticle size analyzer, rotational viscometer, differential scanning calorimetry analysis (DSC),thermogravimetric analysis (TGA), atomic force microscopy (AFM), dynamic mechanicalanalysis (DMA) and contact angle.The experimental results showed that modified acrylic PSA has good integrativeperformance, when the mass fraction of CTA, N-MAM and GH are0.06%,2%and0.5%respectively. And the solid content is above50%, shear resistance force at100℃is above4h,tack is No.25ball, peeling force is21.76N/25mm. PU improved the heat resistance of acrylatelatex PSA. The surface tension, crosslinking density and regularity of PUA increases with theadding of PU emulsion. When the PU contents is30wt%, the acrylate latex PSA has good hasgood adhesive properties and integrative performances, what’s more, the heat resistance ofPUA will also meets requirement.According to Lennard-Jones theory and adsorption theory, the surface tension of acrylatelatexes PSA and surface energy of substrate play a critical role in adhesion force. And thesurface energy of substrate was improved by corona treatment, when the surface tension ofPSA latex is close to the surface energy of substrate, the adhesive force is highest, on other words, the smaller solid-liquid interfacial tension γSL is, the bigger peeling strength have. The models of relation between PU contents and T-peeling strength and adhesive work of PUA to BOPP film were obtained:WΛ=90.46+125.04[PU]-319.96[PU] and T=9.09+96.07[PU]-235.11[PU]2...