The curing performance of UV-curable semi-interpenetrating polymer network structured acrylic pressure-sensitive adhesives

Abstract

This article reports on the curing performance of UV-curable acrylic binders prepared with trifunctional monomers and a photoinitiator. The curing reaction was achieved by direct excitation of pressure-sensitive adhesives (PSAs) by irradiation with a 100-W high-pressure mercury lamp with different UV doses. The curing performance of PSAs was studied by photo-differential scanning calorimetry (photo-DSC), gel-fraction determination and Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy. The reaction rate and extent of UV curing were found to be strongly dependent on the curing rates of the trifunctional monomers, trimethylolpropane triacrylate (TMPTA) and trimethylolpropane ethoxylated (6) triacrylate (TMPEOTA), which have different molecular weights. Exothermic areas increased with increasing acrylic acid concentration. Moreover, gel fractions sharply increased after UV irradiation and then remained constant with prolonged UV exposure. TMPTA blends had higher gel fractions than TMPEOTA blends because of TMPTA's fast curing rate. Also, the gel fractions of TMPTA blends showed no variation with acrylic acid concentration. However, the FTIR-ATR absorption peak areas representing the relative concentration of C=C bonds showed more conspicuous trends for the curing reaction. Although the gel fractions of TMPTA blends showed no differences, the relative concentrations of C=C bonds increased with increasing acrylic acid concentration. In addition, TMPTA blends showed higher relative concentrations of C=C bonds because of the faster curing rate of TMPTA.

UV/UV step-curing of optically clear acrylate adhesives for mobile devices

“…(photo-DSC) The reaction rate can be measured by monitoring the rate at which heat is released from a polymerizing sample, because polymerization is generally an exothermic reaction. Therefore, the profiles of the heat of reaction versus time, obtained by photo-DSC, can be used to characterize reaction kinetics and evaluate polymerization rate constants [30]. The crosslinking sites that remain after primary curing cause an exothermic reaction when exposed to UV during secondary curing.…”

Evaluation of UV-curability of Photo-curable Materials for Acid Free Pressure Sensitive Adhesive

“…These results are the similar to the general trend of UV curable adhesive. [5][6][7] 2-CEAP shows no inclination results which include fibrillation phenomenon in the entire section. Based on these results, AA showed superior results for application to self-cure adhesive material adhesive.…”

Connecting Technology with UV-High Performance andUV-Curable PSA in Electrical/Electronic Industry

“…Our research group reported on the crosslinking performance of the IPN system composed of acrylic binders, tri-functional monomers and a photo-initiator 6) . is formed using TMPTA shown in Fig.…”