Polyamide—epoxy bonding agent

Figures 2 and 3 present typical formulations for a polyamide epoxy bonding agent and a modified coal-tar...

The tire cord fabric is pulled of woven fabric and passes through an impregnating bath with a resorcinol-formaldehyde-latex solution that improves the adhesiveness on the rubber. This impregnating is sufficient for viscose and polyamide, but polyester and aramid have to be pretreated additionally with bonding agents based on epoxy resin. 

The liquid polymer is converted to the rubbery state by reagents that react with mercaptan (-SH) and side groups of the polymer segments by oxidation, addition or condensation to effect sulfide (-S-S-) bond formation. The oxidation reactions are exothermic and accelerated by an alkaline environment. The most commonly employed oxidizing agents which are suitable for curing liquid polymers are cobalt or manganese or lead octoate, p-quinonedioxime and di- or tri-nitrobenzene. Epoxy resin also reacts with liquid polysulfide polymers by addition in the presence of an aliphatic or aromatic amine and polyamide activator as shown in Equation 5.8 ... 

Other crosslinkers such as aromatic amines, dicyandiamide, dihydrazides, and boron trifluoride amine complexes give stable formulations at room temperature and only eine when heated at elevated temperatures. These cme systems are the basis for one part epoxy adhesives. Crosslinkers such as polysulfides and polyamides can be used to increase the flexibility of the adhesive bonds. Other eomponents that may be added to modify the properties of the adhesives are diluents, flexibilizers, modifiers, fillers, and reinforcing agents. 

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