UV固化有机硅压敏胶的研制

Preparation of UV-Curable Silicone Pressure Sensitive Adhesive

以γ-巯丙基三乙氧基硅烷、六甲基二硅氧烷、正硅酸乙酯、水玻璃等为原料,分别采用正硅酸乙酯法和水玻璃法制得巯基硅树脂(RSi-SH),通过红外光谱、核磁共振波谱及凝胶渗透色谱对其结构进行了表征,并对其黏度、密度、折射率和可见光透过率进行了测试。将RSi-SH、乙烯基硅油、锚固剂和光引发剂搅拌均匀后制得紫外光(UV)固化有机硅压敏胶,研究了其光固化动力学、热稳定性、吸水率、透明度、耐水煮老化性、剥离强度、初粘力、持粘力和附着力。结果表明,以水玻璃2.9为原料制得的RSi-SH摩尔质量分布较佳,巯基含量为0.4455 mol/(100 g),M/T/Q值为4.13/4.03/1,R/Si值为1.79,摩尔质量分布系数为1.20,405 nm处透光率为96.06%;当2,4,6-三甲基苯甲酰基膦酸乙酯质量分数为0.80%、辐照强度为80 mW/cm^(2)时,选用水玻璃2.9制备RSi-SH,且巯基与乙烯基的物质的量之比为1∶1的UV固化有机硅压敏胶可在100 s内快速完成交联;所得UV固化有机硅压敏胶的交联密度及热稳定性较优,交联密度为9.03 mol/cm^(3),质量损失率5%时的温度为395℃,最大热分解速率时的温度为570℃;此外,所得UV固化有机硅压敏胶具有较低的吸水率,较高的透明度且无团簇及结晶行为,初粘力、持粘力、剥离强度、附着力及耐水煮老化性能优异。该UV固化有机硅压敏胶应用于涂布行业时,可实现低成本快速涂布成型,有望替代传统热固化有机压敏胶。

The thiol-functionalized silicone resin(RSi-SH)was prepared with 3-mercaptopropyltriethoxysilane,hexamethyldisiloxane,ethyl-silicate and sodium silicate as raw materials,by ethyl-silicate method and sodium silicate method respectively.Its structure was characterized by Fourier transform infrared spectroscopy,nuclear magnetic resonance spectroscopy and gel permeation chromatography and its viscosity,density,refractive index and visible light transmittance were also analyzed.Then UV-curable silicone pressure sensitive adhesive(PSA)was prepared by mixing RSi-SH,vinyl silicone oil,anchor agent and photo-initiator uniformly,and its photo curing kinetics,thermal stability,water absorption,transparency,boiling aging resistance,stripping strength,primary adhesion,holding force and adhesion were studied.The results indicate that RSi-SH prepared from sodium silicate with modulus 2.9 exhibits a better weight distribution,with thiol content of 0.4455 mol/100g,M/T/Q values of 4.13/4.03/1,R/Si value of 1.79,molecular distribution coefficient of 1.20 and the light transmittance at 405nm is 96.06%.When the mass fraction of ethyl 2,4,6-trimethylbenzoylphosphonate is 0.80% and the irradiation intensity is 80 mW/cm^(2),RSi-SH is prepared from sodium silicate with modulus 2.9,and the UV-curable silicone PSA with-SH/-Vi molar ratio of 1/1 can be quickly cross-linked into a three-dimensional network within 100s.The obtained UV-curable silicone PSA has excellent crosslinking density and thermability,with a crosslinking density of 9.03 mol/cm^(3),mass loss rate of 5% at 395℃ and the temperature at the maximum thermal decomposition rate is 570℃.In addition,the UV-curable silicone PSA has low water absorption,high transparency,no clustering or crystallization behaviors,and excellent initial viscosity,holding force,peeling strength,adhesion,and aging resistance in boiling water.When applied in the coating industry,it can realize fast coating molding,cost-saving,and is expected to replace the traditional silicone PSA.