The Synthesis And Application Of Latent Curing Agent For Epoxy Resin

Curing agent plays an important role during the application of epoxy resin.Compared with the apparent curing agent,the latent curing agent of epoxy resin has the advantages of long storage time,convenient operation and low pollution.In recent years,with the wide application of epoxy resin in single component adhesives,sealants,potting compound,electronic slurry et.al,those latent curing agents have attracted much attention and have become a hotspot at home and abroad.Based on those,in this paper,a series of work about the latent curing agent were carried out as follows.(1)Anovel type of latent curing agent(AHUT-1)for epoxy resin was synthesized by the chemical modification of 594 curing agent with propylene oxide phenyl ether(692).After that,the suitable condition of for the synthesis and curing process was discussed.For the synthesis of AHUT-1,the optimal condition was 1:1 of the ratio between 692 and 594curing agent,6 h of reaction time at 120?.For the curing process of AHUT-1,10 wt%of curing agent content and 1.5 h of curing time at140??150?was more appropriate.Under that condition,the epoxy coating had good acid resistance(only 1.76 wt%of weight change was found when the coating being immersed in 1%H₂SO₄solution for 16 h),hardness(2H)and adhesion(grade0).(2)By the chemical reaction between 594 curing agent and propylene oxide butyl ether(660A),another type of latent curing agent(AHUT-1)for epoxy resin was also synthesized successfully.Then,the suitable condition of for the synthesis and curing process was discussed.Under the optimal condition of synthesis(1:1 of the ratio between 660A and 594,4 h of reaction time at 140?)and curing process(10wt%of curing agent content and 1.5 h of curing time at 140??150?),the epoxy coating had good acid resistance(only 1.13 wt%of weight change was found when the coating being immersed in 1%H₂SO₄solution for 16 h),hardness(2H)and adhesion(grade 0).(3)With silver powder as conductive phase,AHUT-1 and AHUT-2 as curing agent,two kinds of conductive silver pastes were prepared,and the properties were also tested.The results showed that when the content of silver was 70?75%,both the two kinds of silver paste had good conductivity(electrical resistivity:1.68?0.44m?·cm;square resistance:99.4?31.8 m?/),hardness(2H?3H)and adhesion(grade1).It is shown that the synthetic AHUT-1 and AHUT-2 have practical application value in the preparation of conductive silver paste.