Aramid cord treatment
A composition and method for treating an aramid cord include a bisphenol-A-based- and/or a bisphenol-F-based-liquid epoxy resin, a reactive diluent, and a curing agent. The composition and method also may include an elastomer-modified epoxy-functional adduct and/or an elastomer-modified epoxy-resin adduct.
1. A method of treating a flexible aramid fiber cord, consisting of the sequential steps of: (1) heating the flexible aramid fiber cord, (2) dipping the aramid fiber cord into a liquid composition consisting of: (i) a liquid epoxy resin selected from the group consisting of a bisphenol-A-based liquid epoxy resin, a bisphenol-F-based liquid epoxy resin and combinations thereof; (ii) 2-ethylhexyl glycidyl ether; and (iii) at least one curing agent, (3) removing any excess liquid composition from the flexible treated cord, and (4) drying the flexible treated aramid fiber cord, wherein the treated aramid fiber cord is flexible enough to be used as a reinforcement in rubber-based products including power transmission belts, hoses, and conveyor belts.
2. The method as specified in claim 1 wherein the treated aramid fiber cord is dried in step (4) at a temperature which is within the range of about 100° C. to about 150° C. for a period of about 10 minutes to about 30 minutes.
3. The method as specified in claim 2 wherein excess liquid composition is wiped off of the treated cord in step (3).
4. The method as specified in claim 1 wherein the liquid epoxy resin is a bisphenol-F-based liquid epoxy resin.
5. The method as specified in claim 1 wherein the curing agent is a polyamide.
6. The method as specified in claim 1 wherein the curing agent is present in an amount of from about 0.6 to about 1.5 times the stoichiometric quantity, as determined using the amine-H-equivalent-weight/epoxide equivalent weight method.
7. The method as specified in claim 1 wherein the excess liquid composition is removed from the flexible treated cord is step (3) by passing the flexible treated cord through an orifice.
8. The method as specified in claim 1 wherein the flexible aramid fiber cord is heated in step (1) to a temperature which is within the range of about 110° C. to about 120° C. for a period of about 12 hours to about 24 hours.
9. The method as specified in claim 1 wherein the flexible treated aramid fiber cord is dried in step (4) at a temperature which is within the range of about 100° C. to about 150° C. for a period of about 10 minutes to about 30 minutes.