Study On The UV-Curing Hot-Melt Pressure-Sensitive Acrylic Adhesive

Hot-melt pressure sensitive acrylic adhesive had the advantages of wide bonding scope, excellent weather resistance and low toxicity. But this kind of pressure-sensitive adhesive products contained monomers which would volatilize when coating and the cohesion strength in high temperature was low. So this kind of adhesive had not been extensively used. Hot-melt pressure sensitive acrylic adhesive can be improved by adding photoinitiator on Macromolecular. Copolymerizable photoinitiator had been used to synthesize the UV-curing Hot-melt pressure sensitive acrylic adhesive in this paper in order to avoid the performance descent by the effect of the photoinitiator residues.According to UV curing mechanism, structure of copolymerizable photoinitiator (UV-A) had been designed. Based on the characteristics of molecular structure, the synthesis method had been identified. The photoinitiator had been composed by 2-HEA, HDI and 4-Dihydroxybenzophenone. Synthesis experiment had two steps, first one was react eight hours at 50℃; the second step was react at 60℃for 10 hours. The analysis of 13 C-NMR indicated that the product's structure accord with the pre-designed molecular structure. The UV spectra analysis indicated that the UV absorption area of UV-A was 280 nm to 380 nm. The maximum absorption peak was at 303 nm. According to the TGA and DSC analysis, UV-A has the melting temperature at 140℃and the melt temperature at 200℃.High-Performance UV-curable hot-melt pressure sensitive acrylic adhesive had been synthesized with UV-A as the photoinititiator in this paper. The monomers were butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, crylic acid and so on. The polymerization was reacted at 69℃for 6h. The coating weight of pressure-sensitive adhesive was 60g/m2. The pressure sensitive adhesive was cured in 50s by the 1kW high-pressure mercury lamp with the distance of 20cm. The effect of different monomer contents on the bonding properties of UV-curable hot-melt pressure sensitive acrylic adhesive had been studied in this paper in order to design different adhesives with different properties. The copolymerizable photoinitiator (UV-A) had the good UV-curing effect on the UV-curing hot melt pressure sensitive acrylic adhesive. And the UV-curable acrylic hot-melt pressure sensitive adhesive has the good physical-chemical properties and anti-aging properties.