자외선 경화형 감압성 점착제의 합성 및 물성연구

Abstract

(1) A series of dual-curable acrylic pressure sensitive adhesives has been synthesized by radical polymerization of acrylic monomers including benzophenone, hydroxyl and alkyl groups. To investigate the optimum UV cure extent, the content of benzophenone group was varied in the range of 0.5 to 1.5%. The weight average molecular weights of the obtained polymers were in range of 300,000 to 700,000. The coated pressure sensitive adhesives were cured either by a short UV exposure to induce the grafting of acrylic polymers, or by heating for 6 hrs at 60 oC, to promote the reactions of polyisocyanates and hydroxyl groups. Both processes were monitored quantitatively by infrared spectroscopy to evaluate the dual-curing behaviors and the developed dual curable acrylic pressure sensitive adhesives were found to compensate the limitation of UV curing in thick coating thickness. (2) Silicone acrylate (SA, 0?10 wt%) and other acrylic monomers including benzophenone and acrylate groups were copolymerized by radical polymerization. The effects of silicone acrylate monomer on the properties of UV-curable pressure sensitive adhesive (PSA) were investigated using Fourier-transform infrared spectroscopy with attenuated total internal reflection (FTIR-ATR), real-time infrared spectroscopy (RTIR), and various physical tests. Spectroscopic analysis showed that the characteristic absorption band at 1660 cm-1 (υ C=O in carbonyl) of benzophenone group was decreased when exposed to UV light, indicating the increase in the cure conversion. As the concentration of SA was increased, both ball-tack and peel strengths were decreased probably due to the flexibility of siloxane chains and lower surface energy of SA, meaning that SA enhanced the release properties of UV-curable PSA.