Paperboard having improved oil resistance

Claim 1

A process for preparing paperboard from cellulosic pulp having improved oil resistance which comprises adjusting the pH of a suspension of cellulosic pulp between 5.8 and 7.3, adding to the suspension an additive mixture of (1) 0.10 to 6.0 percent by weight of a cationically active material selected from the group consisting of cationically active starches and gums and hydrogen bonding starches and gums (2) 0.10 to 10.0 percent by weight of a water soluble salt of a saturated fatty acid having 12 to 20 carbon atoms and (3) about 0.07 to 0.50 percent by weight of a water soluble bis-perfluorosulfonamino alkyl phosphate based on the solids content of the suspension, the bis-perfluorosulfonamino alkyl phosphate having the general formula ##EQU2## wherein R f is a perfluoroalkyl group having 4 to 12 carbon atoms, R is selected from the group consisting of hydrogen and an alkyl group having 1 to 6 carbon atoms and R 1 is an alkyl group having 1 to 6 carbon atoms, precipitating the water soluble fatty acid salt throughout the pulp surface, forming the pulp containing the additive mixture into a fibrous web and then drying the fibrous web to form the oil resistant paperboard.