Research On High Performance UV-curable Pressure Sensitive Adhesive

At present,the addition-type silicone PSA on the domestic market are still solvent-based and heat-cured,which not only has low curing efficiency,but also releases a large amount of VOC during the curing process to pollute the environment.In order to overcome the disadvantage of addition-type silicone PSA,UV curing technology was applied to the addition-type silicone PSA because of UV curing technology has the advantages of low energy consumption,fast curing rate,and no pollution.A silicone tackifier with alkoxy and epoxy groups was prepared,which can enhance the adhesion of silicone pressure-sensitive adhesives to glass and polyethylene terephthalate（PET）.Then,the formula of the addition-type UV-curable silicone PSA was obtained through formula design,and after the improvement of the formula,it was applied to electronic product protection films and labels.The main research contents and achievement are as follows:Firstly,a tackifier（PHMS-12）containing epoxy and alkoxy was prepared,using vinyl trimethoxysilane（A-171）,allyl glycidyl ether（XY680）and hydrogen silicone oil（PHMS）which was prepared through tetramethylcyclotetrasiloxane（D4H）,octamethylcyclotetrasiloxane（D4）,and hexamethyldisiloxane（MM）.The PHMS-12 was characterized by fourier transform infrared spectroscopy（FT-IR）,nuclear magnetic resonance spectroscopy（¹H-NMR）,gel permeation chromatography（GPC）and thermogravimetric analysis（TG）.And the effects of feed sequence and feed rate,material molar ratio,reaction temperature and time,and catalyst amount on the yield and appearance of PHMS-12 were investigated.And The results show that the molar ratio of PHMS:A-171:XY680 was 1:1:1,add XY680 and A-171 at a drop rate of 140 drops/min,the reaction temperature and time of XY680 are 70℃,60min,the reaction temperature and time of A-171 are 80℃,90min,and photocatalyst dosage was1.35x10⁴ppm.On the condition,the yield of PHMS-12 was 85%,the molecular weight of PHMS-12 was 6793 g/mol.Secondly,using vinyl-terminated silicone oil with a viscosity of 1000～100,000m Pa·s（25℃）and a vinyl content of 2.0%,silicone resin with M/Q ratio of 0.8,hydrogen silicone oil,and ethyl acetate as the main raw materials.Photocatalyst was added to prepare a UV-curable silicone PSA.The effects of the mass of silicone resin/vinyl-terminated silicone,the viscosity of vinyl-terminated silicone oil,the ratio of silicon to hydrogen,the amount of photoinitiator,and the number of times of light on the performance of the silicone PSA were investigated.The results show that silicone PSA with a peeling force of 9.0g·25mm^-1 was obtained when the mass of silicone resin/vinyl-terminated silicone oil was 0.8,the vinyl-terminated silicone oil with a viscosity of1000 and 10,000 m Pa·s（25℃）,the silicon-hydrogen ratio was 1.0,photocatalyst dosage was 35ppm and the number of light exposure is 8 times.The silicone PSA with a peeling force of 25.5g·25mm^-1 was obtained when the mass of silicone resin/vinyl-terminated silicone oil was 1.2,the vinyl-terminated silicone oil with a viscosity of 1000、10000 and25000 m Pa·s（25℃）,the silicon-hydrogen ratio was 1.0,solvent content is 20～25%and photocatalyst dosage was 35ppm and the number of light exposure is 8 times.Thirdly,improve the formulation of two pressure-sensitive adhesives with different peeling strengths,applied for protective films,labels,etc.And found the pressure-sensitive adhesives has good performance through the tests of high temperature and high humidity,water boiling and storage performance.