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Hi: I used Epoxy resin and Epoxy harder with MEK to make primer, after = heating to about 80 degree, MEK evaporate , it will curing of course, = however, the curing speed is slow, I like to get the curing time no more =
30 second after MEK evaporate, the surface is no tacky, the production = line can be shorter. Thanks.Chyun Lee
Mr. Lee, the MEK is forming an intermediate compound with the epoxy hardener, you will need to bake the part to complete the cure. In the future, use a different solvent, non-ketone, non-ester, non-epoxide. Benzene, toluene, or xylene should work, of these, benzene has the closest evaporation point to MEK.-Jitney
Thats a lie- MEK is used all the time with epoxy resins. Please don't use benzene!
jitney is right, with ketones you slow down the reactivity of your amine curing agent. Esters however are not at all that reactive, so you could take esters or ethers as solvents instead of benzene, if you don't fancy that. There are however limits to curing rates, it is not flash photography ;-)
cheers
I emailed him privately several times and we arrived at using n-butanol for his application. Esters are okay to use on the epoxy side or in the mix, but putting them on the amine side IME will cause them to break down over a long period of time, forming the alchohol and free acid, which acid presumably associates with the amine. Not crippling, but a PITA for predicting stable work life.-Jitney
Something that I have done in the past to get higher front end strengh and reduce tackyness is use a blend of some faster drying system that is compatable with the same solvent system. It has been a while but I thing I was using an arylic since the amine could cure it quickly and still be free to cure the epoxy. I was using a gas catayst so your milage may vary.
Ghostwriter
Brain failure, it was a SO2 gas catayst and the epoxy/acrylic was blended with a free radical initator. The SO2 cataysted the acrylic quickly at the same time as activating the free radical to kick off epoxy reaction.
Sorry if I confused anyone.
Ghostwriter
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