Preparation And Properties Of High-solid Low Viscosity Epoxy Resin System

The epoxy resins with unique chemical structures have excellent adhesion,chemical resistance,corrosion resistance and electrical insulation after curing,and therefore have been widely used in adhesives,coatings,electronic packaging and other fields.However,the high viscosity of epoxy resins brings some problems to the epoxy system,such as poor fluidity and processability,which limits their applications in high-solid coating.Herein,low viscosity epoxy reactive diluent and epoxy resin were synthesized based on silicone chemistry,respectively,aming to replace conventional solvents and reduce the viscosity of epoxy systems,and then were used to prepare low viscosity epoxy systems for applications in the field of high-solid epoxy coatings.The specific research contents are as follows two parts:(1)Eugenol glycidyl ether(EE)was firstly synthesized from eugenol and epichlorohydrin,and then silicone modified eugenol-based epoxy diluent(HSEE)was prepared from EE and1,1,1,3,5,5,5-heptamethyltrisiloxane(HMTS)through hydrosilylation reaction.The chemical structure of HSEE was characterized.High solid epoxy varnish was prepared by mixing HSEE,epoxy resin E51 with alicyclic amine curing agent 4,4’-Diaminodicyclohexyl methane(PACM).The results showed that HSEE had good compatibility with epoxy resin(E51),and there was no phase separation phenomenon during blending.The viscosity of HSEE modified epoxy reins decreased with the increase of HSEE content.The viscosity of resins with 20 wt%HSEE decreased from 12.17 Pa·s to 1.72 Pa·s.The varnish was coated on the substrate and cured to obtain a series of epoxy coatings with smooth surface morphology and strong adhesion.The toughness,chemical resistance and anticorrosion performances of the epoxy coatings with HSEE were also improved compared with pure E51 coatings.When the addition of HSEE was20 wt%,the comprehensive properties of the coating were optimal.(2)The intermediate(EDBA)was firstly synthesized from 2,2’-diallyl bisphenol A(DBA)and epichlorohydrin,and then low viscosity silicone modified bisphenol A epoxy resin(PSEDBA)was prepared from EDBA and dimethylphenylsilane.High solid epoxy varnish was prepared by mixing the PSEDBA,epoxy resin E51with acyclic amine curing agent(PACM).The structure of PSEDBA was characterized by ~1H NMR and FT-IR,and the effects of PSEDBA addition on the viscosity of epoxy resin E51 were investigated.The effects of PSEDBA addition on the mechanical properties,chemical resistance,thermal properties and anti-corrosion of the cured coating were also studied.The results showed that PSEDBA had a good compatibility with epoxy resin E51,since the PSEDBA molecule contains phenyl glycidyl ether groups similar to epoxy resin.The viscosity of epoxy reins gradually decreased with the increase of PSEDBA content due to the silicone groups with low polarity.The toughness of the PSEDBA modified coating also improved that the impact resistance increased to 100 cm and the flexibility increased to 0 T.The waterproof permeability,chemical resistance and anticorrosion of PSEDBA modified coating were also greatly increased based on the water contact angle test,water absorption rate test,and anticorrosion test.