光固化MT硅树脂的制备及其在LED封装中的应用

Preparation of UV-curing MT Silicone Resin and its Application in LED Packaging

以γ-巯丙基三乙氧基硅烷、六甲基二硅氧烷等为原料,通过水解-缩聚法制得不同结构的巯基MT硅树脂(MT-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表征,并对其黏度、密度、折射率及可见光透过率进行了测试。然后将MT-SH、乙烯基硅油和光引发剂混合均匀后制得UV固化硅树脂,并研究了其光固化动力学、力学性能、热性能、透明性及封装后LED的性能。结果表明,当有机取代基与硅原子的量之比(R/Si值)为2.00、巯基含量为0.47 mol/(100 g)时,MT-SH摩尔质量分布系数为1.16,产率为93.01%;当TPO-L质量分数为0.80%、辐照强度为70 mW/cm^2时,选用R/Si值为2.00的MT-SH且巯基与乙烯基量之比为1.5∶1的UV固化硅树脂可快速交联成三维网络;且随着MT-SH中R/Si值的增大,拉伸强度从2.77 MPa降低至1.86 MPa,拉断伸长率从124.50%提高至194.00%,交联密度从10.22×10^-4 mol/cm^3降低到4.95×10^-4 mol/cm^3,热稳定性先保持稳定后明显下降,可见光透过率总体呈降低趋势;本实验制得的UV固化硅树脂在较低的成本条件下可实现良好的封装效果,未来有望替代传统热固化型LED封装胶实现LED高效封装。

The thiol-functionalized MT silicone resin(MT-SH)with different structures was prepared by hydrolysis-polycondensation with 3-mercaptopropyltriethoxysilane and hexamethyldisiloxane as raw materials,whose structures were characterized by Fourier transform infrared spectroscopy,nuclear magnetic resonance spectroscopy and gel permeation chromatography.Then the viscosities,densities,refractive index and visible light transmittance of the silicone resin were also analyzed.Then UV-curing silicone resin was prepared by MT-SH,vinyl silicone oil and photo-initiator.The UV-curing kinetics,mechanical properties,thermal properties,transparency and performance of LED after packaging were studied respectively.The results indicate that the MT-SH exhibits a molecular distribution coefficient of 1.16 and a yield of 93.01%when the molar ratio of R/Si is 2.00 and the thiol content is 0.47 mol/100g.The UV-curable silicone resin(molar ratio of R/Si and-SH/-Vi is 2.00 and 1.5/1,respectively)can be instantly cross-link into a three-dimensional network when mass fraction of TPO-L is 0.80 wt%and exposes in UV irradiation at 70 mW/cm 2.As the value of R/Si in MT-SH increases,the tensile strength of the resin decreases from 2.77 MPa to 1.86 MPa,the crosslink density decreases from 10.22×10-4 mol/cm 3 to 4.95×10-4 mol/cm 3,and the elongation at break increases from 124.50%to 194.00%.Moreover,the UV-cured resin exhibits an excellent thermal stability at first and then decreases significantly,and its visible light transmittance is decreasing generally;the UV-cured silicone resin resutts in good packaging effects at a lower cost,and is expected to replace traditional thermosetting LED packaging adhesive.