The Dow Chemical Company

Roger L Juhl

Thomas E Morris

James L Potter

Sotiros C Polemenakos

Mark S Johnson

Polyamide solutions for imparting wet strength to paper are stabilized by acidifying uncrosslinked polyamide solutions prior to storage or prior to crosslinking with epichlorohydrin to form polyamide resins. The acidification of the uncrosslinked solutions allows for storage without refrigeration. The acidification prior to crosslinking results in wet strength resins that are stable at solids concentrations of at least 30% and that exhibit high strength when the resins are post cooked to a viscosity of between about 325 and 425 cps.

Stable polyamide solutions

The process is an improvement over the chlorination of EDC in a boiling bed. The reactants, chlorine and dichloroethane (either 1,1- or 1,2-) are mixed in the vapor phase and passed over a molecular sieve which serves as a catalyst to produce 1,1,2-trichloroethane.

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Lake Jackson, TX, United States of America

Roger L Juhl