Preparation And Performance Of Additional Silicone Rubber Adhesive

In the electronic industry, adhesives can be used to meet the development trend of electronic product miniaturization, integration and intelligent. Silicone adhesives are widely used for sealing and bonding of electronic components because of their excellent electrical insulation properties, good chemical stability and low stress. The additional silicone rubbers with simple processing, dimensional stability of products and excellent thermal aging resistance, have a broad development prospect. However, silicone rubbers have low surface free energy and they are generally lack of reactive functional groups, which result in their poor adhesive properties and affect their further applications. In order to improve the bonding performance of silicone rubbers, this paper synthesized a new type of organic silicone tackfier containing epoxy groups, and studied the effect of different type of tackfiers on bonding strength of additional silicone rubbers.Firstly, a series of different formulas of additional silicone rubbers were prepared, and then their mechanical properties and crosslinking density of cured products were tested to investigate the influence of the ratio of Si-H:SiVi, addition of methyl vinyl silicone rubber(raw rubber), different type of vinyl silicone oils, addition of fumed silica on the mechanical properties of additional silicone rubbers. The appropriate mass proportion of catalyst and inhibitor was determined, which can guarantee the additional silicone rubber could be stored at room temperature for a period of time, and cured at high temperature rapidly.A new type of organic silicone tackfier containing epoxy groups was synthesized via the hydrosilylation between siloxane containing silicone-hydrogen bond and unsaturated hydrocarbon containing epoxy groups. The influence of different reaction conditions on the synthesis of tackfier was studied. Furthermore, the structure and epoxy value were characterized by FT-IR, 1H NMR, hydrochloric acid- acetone method, respectively. The results showed that the reaction was efficient and the products was transparent under the reaction factors with toluene as solvent, Karstedt catalyst catalyzed the hydrosilylation, the ratio of reactant of 1:5, the reaction temperature of 60~80? and the reaction time of 4~5h.The bonding properties of additional silicone rubber can be improved significantly by adding the tackfier. Especially when the structure of tackfier contained epoxy groups, the boning strength was increased more obviously. After adding the organic silicone tackfier containing epoxy groups, with the increase of curing temperature and cuing time, the shear strength of silicone rubbers was significantly enhanced, which may be because a period of time at higher temperature was required for the formation of strong interaction between the epoxy group and the metal surface, and the improvement of the bonding strength.