have you tried the DMP-30 to accelerate the binding?

The hardeners with the highest activity are mercapatanes. Commercially available is Thiocure TMPMP, TMP- trismercaptopropionate, which is also available from SIGMAALDRICH. One mercapto groups must be applied on one epoxide group. Strong bases, like DBU or DABCO, in catalytical amounts further accelerate this reaction so that room temperature curing in some minutes is possible. Perhaps a part of the mercapto compound can be replaced by an amine like IPDA or TETA to increase hardness but some reactivity is sacrificed or higher temperatures are required.

I recommend nercaptanes like PEMP(Pentaerythritol tetrakis 3-mercapto propionate). You have to use mercaptanes with DMP-30(=Ankamine K-54, like tertiary amine catalyst).

And... Have you tried the Accelerator-2950CH(Huntsman) to accelerate the system? It has active hydrogen. It can participate in the curing mechanism.

Thank you both.  What level of mercaptane do you suggest, 1% on total resin/hardener mix?

Dongyun Kim:

Thanks for the input.  The issue I have is the epoxy I am trying to cure is an epoxidized soybean oil resin (ESO) that has internal oxirane units that are hard to get activated.  Do you still feel that the mercaptans will accelerate the ESO/phenylamine system?  

Terry

you must use one mercapto group per one epoxy group. The equivalent weight of TMP tris mercaptopropionate is 131 g/eq. The equivalent weight of a typical epoxidized soybean oil is 242 g/eq - that means that you must mix 24 g epoxidized soybean oil with 13 g Thiocure TMPMP. You can also use a slight excess of epoxidized soybean oil to ensure that all mercapto groups are reacted. Basic catalysts like DMP-30 or DBU can be used  in amounts of some weight %.

Burkhard:

Thanks for the feedback..   I am developing an all bio-based epoxy system for concrete floors.  Am I correct in assuming that mercaptans with the sulfur molecule does not fit in the definition of bio-based or non petroleum based epoxy?.

Terry

Commercially available mercapto-hardeners are not bio-based but neither the normally used amino hardeners. You must live with the fact that only two-thirds of the resulting material is from renewable resources. The only diamine from fatty chemistry feed-stock is Dimer Diamine from CRODA available under the trade name Priamine 1071. It has a equivalent weight of 133 g/eq calculated under the premise that one amino group reacts with two epoxy groups. Using Priamine as hardener you need 24 g epoxidised soybean oil and 13 g Priamine (some epoxy excess can be advantageously if accelerators are used). This epoxy resin would be 100% from renewable resources but at room temperature it is rather slow in cross-linking (several days until tack free). Accelerators from which 2-6 weight-% can be added are benzyl alcohol, nonylphenol, DMP-30, triethanolamine or benzyltrimethylamine. DMP-30 is often the best, benzyl alcohol lowers the viscosity which is pleasant for some applications.