| Preparation of latent curing agent and its solvent-free insulating resin hasbecome a hot research topic in the field of epoxy resin. Currently, Adding reactivediluent to solvent-free insulating resin is still contaminate environment and hasimpaired performance of the curing product to some extent. Therefore, thedevelopment of non-reactive diluent and solvent-free insulating impregnant resin hasbecome a key technology. This article studied the effect of latent accelerator onproperties of cured samples, including the storage stability, dielectric property,mechanical performance and VOC content. The optimum formulas ofone-component solvent-free insulating impregnant resins (Class F and Class H) areobtained. The detailed contents include the following aspects:(1) Based on cationic latent accelerator，the role of latent accelerator inmethylhexahydrophthalic anhydride (MeHHPA)/bisphenols A epoxy resin(DGEBA) was studied. And various factors affecting the properties of cured samples,including mechanical properties, thermal stability, dielectric properties and storagestability, gel time, curing temperature, volatile, dielectric constant, viscosity werediscussed too. When the amount of HBT104is0.4wt%, we obtained one-componentsolvent-free insulating impregnant resins that the viscosity of resin increased nomore than0.2times for144h under50℃. After the cure condition of120℃/5h+160℃/4h+180℃/3h+200℃/2h, the heat temperature of cured sample reached169℃，which indicate that one-component solvent-free insulating impregnant resins(Class F)were obtained.(2) We discussed the role of latent accelerator in methylnadic anhydrideMNA/epoxy resin (HBP180). And various factors affecting the properties of curedsamples, including mechanical properties, thermal stability, dielectric properties andstorage stability, gel time, curing temperature, volatile, dielectric constant, viscosity,etc.were discussed too. When the amount of HBT105is0.2wt%, we obtainedone-component solvent-free insulating impregnant resins that the viscosity of resin increased no more than0.7times for96h under50℃. After the cure condition of120℃/5h+160℃/5h+180℃/4h+220℃/4h, the heat temperature of cured sample reached181℃， which indicate that one-component solvent-free insulating impregnantresins(Class H) were obtained.(3) Introducing HERSS-3into the MeHHPA/DGEBA system to explore thecontent of hyperbranched polymer effect on the properties of curing materials, suchas gel time, volatiles and heat resistance. Results indicated that the hyperbranchedpolymer accelerate curing process apparently,and the cured product has a low VOCcontent of2.64%, however, the heat resistance of the cured product has no differencecompared with blank experiment.(4) Novel sulfur-containing epoxy resin through click reaction was synthesizedby using trimethylolpropane tri-(3-mercapto propionate) and glycidyl methylacrylate as raw material. The structure and thermal properties of product werecharacterized by FT-IR,1H-NMR, DSC, TG. Results show that glass transitiontemperature and thermal decomposition temperatures of the cured sample were72℃and310.9℃. |
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