Preparation And Performance Study Of Non-reactive Diluent Epoxy Acrylate Pressure Sensitive Adhesive

This paper aims to solve the problems of small molecule reactive diluents in pressure-sensitive adhesives.Solvent-free epoxy acrylate prepolymers were synthesized from monomers butyl acrylate(BA),isooctyl acrylate(2-EHA),glycidyl methacrylate(GMA)and acrylic acid(AA),and hydroxyethyl methacrylate(HEMA),with dodecyl mercaptan(DDM)as the chain transfer agent and dibenzoyl peroxide(BPO)as the initiator for free radical polymerization.Then,two different curing methods of acrylate pressure-sensitive adhesives without reactive diluents were prepared by adding cationic UV initiator to the prepolymer,and a UV-initiated self-crosslinking epoxy acrylate pressure-sensitive adhesive without reactive diluents was prepared.The other is to add KH550 silane coupling agent to the prepolymer to produce a wet and heat dual-curing epoxy acrylate pressure-sensitive adhesive without reactive diluent.1.UV-initiated self-crosslinking epoxy acrylate pressure-sensitive adhesive:Cationic UV initiator 6976 was added to the prepolymer,and a solvent-free,non-reactive diluent monomer,low-odor UV-initiated self-crosslinking epoxy acrylate pressure-sensitive adhesive(PSA)was prepared after coating and light exposure.The effects of AA and GMA dosage,photoinitiator dosage and curing time on the performance of the products were investigated.The structure,glass transition temperature and thermal decomposition were characterized by Fourier infrared spectroscopy(FTIR),differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA),respectively.The results showed that the amount of acrylic acid was 3.5%,the amount of glycidyl methacrylate was 12.5%,the amount of photoinitiator 6976 was 2%,and the curing time was 40s.The resulting PSA had an initial adhesion of 11.1N/25mm,a peel force of14.5N/25mm,a shear strength of 9.9N/12×12mm~2,and good heat resistance at 80°C.2.Wet and hot dual-curing epoxy acrylate pressure-sensitive adhesive:add aminosilane coupling agent KH550 to the prepolymer,mix with the prepolymer,coat on polyester film,and heat-cure in an oven at 80℃,then wet-cure in air at 25℃with 50%relative humidity,and the alkoxy reacts with the moisture in the air to get epoxy acrylate pressure-sensitive adhesive.The effect of KH550 dosage and curing time on the mechanical properties of the pressure-sensitive adhesive and the determination of the wet curing time were investigated,and the structure,glass transition temperature and thermal decomposition were characterized by Fourier infrared spectroscopy(FTIR),differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA).The results showed that the best performance of the pressure-sensitive adhesive was obtained after curing at 3h,the ratio of KH550 to acrylate prepolymer was 1:30,and the resting time in air was 2d,and the initial adhesive force reached 8.4N/25mm,the peel force reached15.5N/25mm,and the shear strength reached 9.2N/12×12mm~2.