Study On The Synthesis And Application Of The Rapid Curing Agent For Epoxy Resin

Polymercaptan is a new curing agent of epoxy resin.Its molecule structure contains two or more sulfhydryl groups,which could cure epoxy resins at room temperature and-10℃.Polymercaptan has the advantages of low chroma,high refractive index,high bonding strength and low curing shrinkage,which can be widely used in photovoltaic cutting adhesives,general adhesives,sealants,electronic adhesives and other fields.In this thesis,the synthesis and application of polymercaptan-type fast curing agent for epoxy resin were developed.In this thesis,a novel process of sulfureted hydrogen mercaptolation of macromolecular mercaptan was developed,and the curing agent of polysulfide was prepared by the directional sulfuretted addition of epoxide and hydrogen sulfide.The performances of polysulfide epoxy resin adhesives were also studied.Firstly,the synthesis process of a polymercaptan fast-curing agent for epoxy resin was determined.By using polyether polyols and epichlorohydrin as raw materials,the intermediate A₁ of chloro-alcohol ether was synthesized under the action of catalyst-1 at a reaction temperature of 70℃,a ratio of epichlorohydrin to hydroxyl group 1.4:1,and catalyst 0.4%through the verification of catalyst type and reaction conditions.Then,the intermediate A₁of chloro-alcohol ether was used as raw material,and determine the reaction temperature below 50℃.The molar ratio of lye to the intermediate A₁ of chloro-alcohol ether was 1.3:1.At the same time,the epoxidation intermediate A₂ was prepared by adding Na OH in batches.Then,using epoxidation intermediate A₂ as raw material,polymercaptan curing agent was prepared under the catalysis of resin 1 at the reaction temperature of 60～70℃and the molar ratio of H₂S to epoxy intermediate A₂ at 7～9:1.Secondly,by studying the composition of polymercaptan epoxy resin adhesive and curing process on adhesive properties,this thesis determined the influence rules of adhesive composition and curing process on curing properties.With the increase of curing temperature,curing time of adhesive was gradually shortened,and its crosslinking density first increased and then decreased.When different types of accelerators were added,the properties of the cured products were greatly affected.For example,when the accelerant-1was added,the product showed high bonding strength and brittleness.When low molecular weight polymercaptan was used as diluent,the adhesive property of the product was improved,and the toughness of the product was decreased.The formulation can be adjusted and active diluent could be added to adapt to different application scenarios.And this thesis developed a synthesis process of polymercaptan active diluent pentaerythritol tetra（3-mercaptopropionate）products.