Modified acrylic emulsion pressure sensitive adhesive

Emulsion pressure-sensitive adhesive has many advantages such as a simple synthesis process, no pollution, low VOC content, and low cost, so its market prospect is broader and broader. However, the common emulsion pressure-sensitive adhesive still has some shortcomings, such as a weak balance of adhesion/peeling strength, poor water resistance, and durability, so it is difficult to meet the requirements of high-end pressure-sensitive adhesive fields.

In order to improve the properties of pressure-sensitive adhesive, the high-performance pressure-sensitive adhesive emulsion can be prepared by modifying adhesive resin, reactive emulsifier, and nanoparticle. Among many modification studies, there are relatively more reports on the modification of viscosified resin, but there are some problems such as the change of emulsion properties and the decrease of adhesion caused by viscosified resin. In addition, crosslinking modification is one of the most effective methods to improve the properties of emulsion pressure sensitive adhesive.

By introducing functional monomers with cross-linked groups in the emulsion preparation process, the cross-linking reaction occurs during film formation to form a three-dimensional network structure. At present, the crosslinking systems commonly used for emulsion pressure-sensitive adhesives include epoxy resin, ketone carbonyl group, acrylamide and so on.

Recently, acetoacetyl group, as a new reactible active group, can react with metals, amines, isocyanates, active alkenes and aldehydes. The main monomer containing acetoacetyl group is acetoxy-ethyl methacrylate (AAEM), which is relatively low toxicity and has attracted wide attention in the field of crosslinking modified emulsion. Using AAEM as modified functional monomer and aziridine as curing agent, Zhang Yubo et al. prepared two-component water-based acrylate coatings and applied them in the field of coatings.

Lei Liang et al. modified acrylic ester with AAEM and synthesized polymer emulsion with 10% hexamethylene diamine solution as curing agent, and discussed the influence of different AAEM dosage on the properties of the film. Wang Xiaorong et al. synthesized room temperature self-crosslinking acrylate emulsion with AAEM as functional monomer and diacylhydrazine carbonate as crosslinking agent, and prepared water-based varnish. However, the application of AAEM functional monomer modified acrylate emulsion to pressure sensitive adhesive is rarely reported.