Synthesis of silane oligomers containing vinyl and epoxy group for improving the adhesion of addition-cure silicone encapsulant

Two types of silane oligomers containing vinyl and epoxy group (PTGM and PTGE) as adhesion promoters were synthesized by the reaction of trimethylolpropane monoallyl ether with 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane, respectively. Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, and gel permeation chromatography were used to characterize their chemical structures. The effect of adhesion promoters on properties of addition-cure silicone encapsulant (ASE) with lots of alumina (Al₂O₃) particles as thermally conductive fillers was investigated. The results showed that PTGM and PTGE could significantly improve both the adhesive strength and mechanical properties of ASE. The viscosity of ASE with no more than 3.0 phr PTGM and PTGE was below 5000 mPa s so that they were suitable for encapsulating process. Observation using scanning electron microscopy revealed that PTGM and PTGE could improve the dispersion of Al₂O₃ particles in silicone rubber matrix and enhance the bond between the particles and the matrix.     

The synthesis,characterization and properties of silicone adhesion promoters for addition-cure silicone rubber

Two types of polysiloxanes, GVPMS and GVHMS, were synthesized through nonhydrolytic sol-gel reaction from vinyltrimethoxysilane(VTMS), 3-glycidoxypropyltrimethoxysilane(KH560) and diphenylsilandiol(DPSD) or hydroxyl silicone oil, respectively. The chemical structures were characterized by Fourier transform infrared (FTIR) spectroscopy, ¹H nuclear magnetic resonance (¹H-NMR) spectroscopy and gel permeation chromatography (GPC). GVPMS and GVHMS were used as adhesion promoter for addition-cure silicone rubber. It was found that the adhesion promoters not only greatly improved adhesion strength but also had excellent compatibility with silicone rubber. Among them, GVPMS gave better adhesion strength in silicone rubber. The shear strength of silicone rubber reached 1.70 MPa with addition of 1.5 phr GVPMS, which was about 317% higher than that of silicone rubber without the adhesion promoter. Meanwhile, the shear strength of silicone rubber reached 1.14 MPa with addition of 2.0 phr GVHMS, which was 183% higher than that of silicone rubber without the adhesion promoter. Optical property test results revealed that the refractive indexes of GVPMS and GVHMS were 1.5185 and 1.4133 respectively and both of them had good compatibility with silicone rubber, which satisfied the application demand of high-refractive and low-refractive electron encapsulation. Thermal resistance test and SEM results further proved that adhesion promoter could significantly increase the adhesion between the copper substrate and silicone rubber, in which GVPMS had a better performance. Oxidation treatment experiment further explained the mechanism that adhesion promoter functioned as a bridge, linked silicone rubber and copper substrate through chemical bonds.     

高折光指数含硅环氧树脂的合成与性能研究

将二苯基二氯硅烷经过氢化铝锂还原为二苯基硅烷,再与4-乙烯基环氧环己烷进行硅氢加成后合成了1种新型含硅环氧树脂二[2-(3,4-环氧环己基)乙基]二苯基硅烷(EODPS)。该树脂的折光指数达到1.567,并具有较好的透明度。采用甲基六氢苯酐和乙酰丙酮铝-二苯基硅醇组合物分别对EODPS进行固化。通过红外光谱,DSC分析表征了EODPS的结构,研究了其固化活性,并对固化后产物的热稳定性、力学性能和吸水性进行了测试,且与脂环族环氧树脂CEL-2021P性能进行了比较。结果表明,与CEL-2021P相比,EODPS具有更高的热稳定性和更低的吸水率,可用于LED封装。     

Synthesis of a boron-containing adhesion promoter for improving the adhesion of addition-cure silicone rubber to PPA

Abstract

In this study, a boron-containing adhesion promoter PhBSiO with a high refractive index and MeBSiO with a low refractive index were synthesized by a non-hydrolytic sol-gel reaction. The chemical structures of the synthesized adhesion promoters were firstly characterized by infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). Then, the effects of adhesion promoters on the bonding properties of the cured silicone rubber were analyzed and the compatibility of the adhesion promoters to the silicon rubber was further studied through light transmittance detection. The boron-containing silicone adhesion promoters significantly enhanced the bonding strength of the cured silicone rubber to poly-phthalamide (PPA). When the addition amounts of PhBSiO and MeBSiO was 3.0 phr, the shear strength between silicone rubber and PPA respectively reached 0.761?MPa and 0.809?MPa, which were 145% and 161% higher than that of silicone rubber without adhesion promoter. In addition, the adhesion mechanism of the boron-containing adhesion promoter was investigated. The microscopic morphology of the fractured surface of the cured silicone rubber further demonstrated that boron atoms in the adhesion promoters significantly improved the adhesion strength between silicone rubber and PPA.     

高折射率含硫环氧树脂的合成与表征

利用间接法以巯基乙醇和环氧氯丙烷 (ECH)为原料通过 3步反应得到 2 ,3 二 (2 ,3 环氧丙硫乙硫基 )丙基·2 ,3 环氧丙基硫醚型环氧树脂 (TGEBES) ,其折射率和环氧值分别达 1.5 85 0和 0 .5 3;在没有任何催化剂的条件下 ,按以三元硫醇 (BES)和ECH物质的量比为 1∶3.6、在温度为 0～ 5℃下反应 3～ 4h ,环氧化反应的产率达到84 .5 %。并利用红外光谱和核磁共振对含硫高折射率环氧树脂的结构进行了表征 ;利用高效液相色谱对TGEBES和BES的纯度进行了测定 ,结果表明TGEBES和BES纯度分别达 96 %和 97.7%以上。     

高折射率含硫环氧树脂PTETE的合成与表征

以苯硫酚、氯乙醇和环氧氯丙烷为原料,通过直接法合成高折射率苯硫基乙基-2,3环氧1丙硫醚（PTETE）环氧树脂。研究了原料配比、温度和氢氧化钠的用量等因素对产物产率的影响。得出最佳反应条件为：反应温度为0～10℃,环氧氯丙烷、MEPS与NaOH摩尔比为1．25：1：1,产率91．50％,产物的折射率1.6016。并通过FT-IR对合成的原料和产物进行表征。     

含有环氧基的丙烯酸酯的合成及其固化物的研究

采用脂肪族环氧树脂(EP-664)与丙烯酸(AA)合成了低黏度的含有环氧基的丙烯酸酯(AEG),该反应性酯类化合物与双酚A型环氧树脂(E-44、EP-6002)共混,以甲基六氢苯酐(MeHHPA)为固化剂,并分别采用三级胺和2-乙基-4-甲基咪唑(2E4MZ)为促进剂,通过混合物黏度曲线的变化与其固化物力学性能的测试,研究了AEG含量对环氧树脂体系黏度的变化和固化物力学性能的影响。结果显示,AEG的添加可以有效地降低树脂体系的黏度,25℃下混合体系黏度仅为300～600mPa·s;其固化物的力学性能随AEG含量的增加先增加后降低,具有最大值。三级胺固化体系的力学性能明显优于2E4MZ固化体系,当w(AEG)为20%时,固化物的综合力学性能最好。     

环氧有机硅油改性丙烯酸树脂的合成及性能

以偶氮二异丁腈为引发剂,通过丙烯酰氧基硅油与丙烯酸酯类单体的自由基共聚合反应,同时环氧828与丙烯酸共聚侧链羧基进行开环反应,合成以乙醇为主要溶剂的单相均匀牛顿型环氧有机硅油改性丙烯酸树脂。并对树脂涂膜的稳定性及硬度、耐水煮性,附着力等性能进行了研究。得到的树脂具有良好的热储稳定性,颜料广泛润湿性。环氧有机硅油改性丙烯酸树脂涂膜具有光泽高、硬度好、丰满度高、玻璃附着力强、耐水煮性好与透明性高等优异性能,适用于高档玻璃烤漆。     

Investigation of ureido-attached vinyl MQ silicone resin on tracking and erosion resistance of addition-cure liquid silicone rubber

With the growing incidence of extreme climate and serious pollution, the capability to resist high-voltage arc discharge has been considered as one of crucial performances for silicone rubber in the field of electrical power. Herein, to enhance the tracking and erosion resistance of addition-cure liquid silicone rubber (ALSR), a kind of ureido-attached vinyl MQ silicone resin [hydrolytic condensation products of monofunctional silane (M) and tetrafunctional silane (Q)] (U-VMQ) was synthesized. The chemical structure of U-VMQ was characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance, and the effects of U-VMQ on the mechanical properties, thermal stability, and tracking and erosion resistance of ALSR were investigated. The results showed that U-VMQ was beneficial for the improvement of mechanical properties and thermal stability of ALSR. With 2 phr of U-VMQ containing 2.5 wt % of vinyl content, the ALSR successfully passed the inclined plane tracking at 4.5 kV, and the electrical erosion rate was only 0.13%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47360.     

Synthesis and properties of optically clear silicone resin/epoxy resin hybrids

Optically clear silicone/epoxy hybrid resins were synthesized. The silicone resin (SiR) carrying Si? H, Si? CH?CH₂ and Si? OH groups was prepared by hydrolytic condensation. The blends of SiR and diglycidyl ether of hydrogenated bisphenol A (DGEHBA) were cured through platinum‐catalyzed hydrosilylation and aluminium acetylacetonate‐catalyzed polymerization. The curing process was studied using differential scanning calorimetry and rigid‐body pendulum rheometry. It was found that the ratio of SiR to DGEHBA plays a major role in the curing process. The Si? OH groups of SiR assist polymerization of DGEHBA, and react with the epoxy resin to prevent phase separation. The cured hybrid resins are single‐phase materials with a transmittance of about 87% at 400 nm for a thickness of 3 mm using air as reference. UV resistance and thermal stability of the hybrids are largely dependent on the composition. The adhesive strength of the SiRs can be significantly improved by a small fraction of DGEHBA, with a marginal influence on UV resistance. However, increasing the epoxy proportion has a marked negative influence on thermal stability. Compounding stabilizers, especially thermal stabilizers, are essential, in particular for high epoxy content, if the hybrids are to be used for high‐brightness light‐emitting diode packaging. Copyright © 2011 Society of Chemical Industry     

丙烯酸酯液体橡胶的合成及其增韧环氧树脂的研究进展

综述了反应性丙烯酸酯液体橡胶的合成方法及其用丙烯酸酯液体橡胶增韧环氧树脂的研究进展。其合成方法以溶液聚合为好,聚合产物以三元共聚物为好。增韧效果与体系的相态结构、化学键合和环氧基体的延展性有关。     

Preparation and performance of high refractive index silicone resin‐type materials for the packaging of light‐emitting diodes

A novel high refractive index and highly transparent silicone resin‐type material for the packaging of high‐power light‐emitting diodes (LEDs) is introduced, which was synthesized by hydrosilylation of vinyl end‐capped methylphenyl silicone resin and methylphenyl hydrosilicone oil catalyzed by Karstedt's catalyst. The vinyl end‐capped methylphenyl silicone resins were prepared by hydrolysis?polycondensation method from methylphenyl diethoxysilane (MePhSi(OEt)₂), phenyl triethoxysilane (PhSi(OEt)₃), and vinyl dimethylethoxy silane (Me₂ViSiOEt) in toluene/water mixture catalyzed by cation‐exchange resin. The vinyl end‐capped methylphenyl silicone resins were characterized by ¹H‐NMR and Fourier‐transform infrared. The performances of the cured silicone resin‐type materials for LED packaging have been examined in detail. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

埃洛石固载铂催化合成硅骨架环氧树脂

以天然纳米管状埃洛石为载体,负载氯铂酸制得埃洛石固载铂催化剂,催化1,1,3,3-四甲基二硅氧烷和甲基丙烯酸缩水甘油酯的硅氢加成反应,合成一种硅骨架环氧树脂,产率达到93.26%。利用SEM和TEM表征了埃洛石固载铂催化剂的形貌。结果显示,纯化后的埃洛石呈纳米管状结构,管长为0.5~1.5μm,管外径为50~190nm,管内径为10~20nm,管体清晰,表面干净规整,固载铂催化剂后,催化剂颗粒在埃洛石表面均匀分布。利用红外光谱和氢核磁共振谱对硅骨架环氧树脂结构进行了表征。     

有机硅改性环氧树脂粘合剂的研制

采用含活性氨基的SR22000有机硅树脂、ECC202环氧树脂、K-12固化剂和2E4MI固化促进剂为原料,通过配方设计,制得了有机硅改性环氧树脂粘合剂体系,并研究了SR22000的用量对粘合剂体系性能的影响。     

A facile route to prepare homogeneous silicone resin doped with titanium

A facile route was introduced to prepare homogeneous silicone resin doped with titanium hybrid with high refractive index (RI). Specifically, the hybrids were obtained from the transesterification of hydroxyl-phenyl-vinyl silicone resin and titanium isopropoxide under anhydrous conditions. The structures of hybrid silicone and their corresponding intermediates (hydroxyl-phenyl-vinyl silicone) were characterized by nuclear magnetic resonance spectroscopy (¹H NMR, ²⁹Si NMR) as well as Fourier transform infrared spectroscopy (FTIR). The hybrids had a transmittance of more than 88% ranging from 450 nm to 800 nm, a high RI of 1.585, and a lower water vapor permeability of 3.58 g /m².24h. Results from FTIR showed intensity of Ti-O-Si bond in hybrid decrease with extended the storage time, but the properties of cured hybrids including optical, mechanical, and gas permeability were not influenced. Compared to chips encapsulated with pure silicone, the luminous efficiency of the chips encapsulated with hybrids was improved from 138.6 lm/W to 156.4 lm/W. The thermal shock and hygrothermal aging test also demonstrated the hybrids had a wide range application in light-emitting diode (LED) packaging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47834.     

甲基苯基硅树脂的制备工艺优化及阻燃性能

以苯基甲氧基硅烷和甲基甲氧基硅烷为原料,用水解缩合法制备硅树脂阻燃剂,通过对反应时间、反应温度、催化剂量和封端时间等因素的正交实验分析,优化硅树脂阻燃剂制备条件.结果表明：硅树脂具有良好的热稳定性,在800℃、N₂气氛下,热失重低于39%,其热稳定性越好,对聚碳酸酯（PC）的阻燃效果越佳.在PC中添加5 %（质量）优化条件制得的硅树脂就能使其氧指数（OI）从26.0提高到34.0.     

Preparation and characterization of high refractive index thin films of TiO2/epoxy resin nanocomposites

By using sol–gel method, amorphous titania was introduced into epoxy matrix to prepare a series of high refractive index TiO₂/epoxy resin nanocomposite films. To increase the refractive index of the hybrid films, triethoxysilane‐capped trimercaptothioethylamine (TCTMTEA), a new kind of high refractive index coupling agent was synthesized from trimercaptothioethylamine (TMTEA). In the experiment, TCTMTEA acted as the solidification agent together with TMTEA except being used as the coupling agent. The hybrid films have been characterized via FTIR, AFM, DSC, TGA, etc. The experimental results showed that the amorphous TiO₂ had been dispersed uniformly in the organic polymer matrix with the size smaller than 100 nm in each sample. More importantly, the refractive index of this kind of materials can be continuously adjusted from 1.61 to 1.797 with the content of TiO₂ increasing from 0% to 65% in mass, and the continuously adjusted refractive index is very important for the applications in optical antirefractive films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1631–1636, 2006     

Plasma‐graft polymerization of vinyl monomer with an acid amide group onto a surface of carbon fiber and its adhesion to epoxy resin

The mechanical properties of a fiber‐reinforced plastic are influenced by the adhesion between a reinforced fiber and a matrix resin. In this work it is shown how to obtain strong adhesion between a carbon yarn and an epoxy resin through the formation of covalent bonds. Acid amide groups reactive with epoxy groups were introduced onto a surface of the yarn by means of plasma‐graft polymerization of acrylamide. The density of active radicals formed on a surface of the yarn by the plasma irradiation was first increased with increasing discharge power and plasma irradiation time, and then the rates of the increase were largely decreased. The degree of grafting was linearly increased with increasing the surface density of active radicals. The yarn embedded in diglycidyl ether of bisphenol‐A/triethylenetetramine mixture was pulled out to obtain pull‐out force after curing. Pull‐out force was increased with increasing degree of grafting and the failure in pulling out of the yarn was cohesive. The covalent bonds formed in the graft layer will result in an increment of pull‐out force. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 284–290, 2000     

高固含量有机硅改性丙烯酸酯微胶乳的合成及性能

用自制的由阴离子乳化剂十二烷基硫酸钠(SDS)、非离子乳化剂辛基酚聚氧乙烯醚(OP-10)、反应型乳化剂WH-100以及非离子表面润湿剂所组成的混合乳化剂体系,通过半连续单体滴加法合成了平均粒径为59·8nm、粒径分布窄、总固物质量分数达40%的有机硅改性丙烯酸酯微胶乳,并对微胶乳及胶膜的性能进行了研究。结果表明,与间歇预乳化法制备的乳液相比,有机硅改性丙烯酸酯微胶乳的钙离子稳定性较差,其胶膜的吸水率较小,凝胶含量相当;随着乙烯基三乙氧基硅烷(A151)用量的增加,对转化率的影响不明显,微胶乳的钙离子稳定性、胶膜的吸水率下降,乳胶粒子的粒径变大,A151的质量分数宜为4%;随着功能单体甲基丙烯酸-2-羟乙酯(HEMA)用量的增加,微胶乳的钙离子稳定性先提高后降低,而胶膜的吸水率先降低后增大,HEMA的质量分数不宜超过3%。     

Synthesis and properties of urethane elastomer-modified epoxy resin having hydroxymethyl group

Synthesis and properties of urethane elastomer-modified epoxy resins were studied. The urethane elastomer-modified epoxy resins were synthesized by the reaction of a 4-cresol type epoxy compound having hydroxymethyl groups (EPCDA) with isocyanate prepolymer. The structure was identified by IR, ¹H NMR and GPC. These epoxy resins (EPCDATDI) were mixed with a commercial epoxy resin (DGEBA) in various ratios. The mixed epoxy resins were cured with a mixture of 4,4′-diaminodiphenylmethane and 3-phenylenediamine (molar ratio 6:4) as a hardener. The curing behaviour of these epoxy resins was studied by DSC. The higher the concentration of EPCDATDI, the higher the onset temperature and the smaller the rate constant (k) of the exothermic cure reaction were. It was considered that the ratio of hydroxymethyl group to epoxide group was very small and the molecular weight of EPCDATDI was large. Therefore, the accelerating effect of the hydroxymethyl group on the epoxide–amine reaction was cancelled by the retardant effect of increased molecular weight and viscosity, and decreased molecular motion. Toughness was estimated by Izod impact strength and fracture toughness (K_1C). On addition of 10 wt% EPCDATDI with low molecular weight (M?_n 6710, estimated by GPC using polystyrene standard samples), Izod impact strength and K_1C increased by 70% and 60%, respectively, compared with unmodified epoxy resin. Glass transition temperatures (T_g) for the cured epoxy resins mixed with EPCDATDI measured by dynamic mechanical spectrometry were the same as those of unmodified epoxy resin. The storage modulus (E′) at room temperature decreased with increasing concentration of EPCDATDI. Toughness and dynamic mechnical behaviour of cured epoxy resin systems were studied based on the morphology.