Method of producing pulp

Claim 1

In a method of preparing pulp from a lignocellulosic material by subjecting said material to an alkaline pulping liquor at a select temperature, pressure and time period to attain a pulp having a select Kappa number range, the improvement comprising: (a) adding an amount up to about 10% by weight, based on a 100% weight basis of dry pulp being produced, of a digestive additive selected from the group consisting of alphasulfo alkyl esters, alkaryl sulfonates, alkanolamides, and mixtures thereof to said alkaline pulping liquor whereby a reduction of alkaline pulping liquor requirements, a reduction of H-factor, a reduction in material reject percentages, and a reduction in cooking time period is attained; (b) discharging said pulping liquors and the at least partially delignified lignocellulosic material to attain a pulp slurry; and (c) displacing said pulping liquor from said partially delignified lignocellulosic material with water or an aqueous liquor to attain a pulp having said select Kappa number range.

Claim 22

A method of producing a paperboard pulp having a Kappa number in the range of about 30 to about 110 from a lignocellulosic material comprising: (a) feeding an amount of said lignocellulosic material to a digester capable of yielding a given amount of paperboard pulp; (b) adding a sufficient amount of an alkaline pulping liquor to said digester to attain a select liquor-to lignocellulosic material ratio therein, said pulping liquor including therein an amount up to about 10%, based on a 100% total weight basis of dry paperboard pulp being produced, of a digestive additive selected from the consisting of sodium alpha-sulfo methyl laurate, sodium xylene sulfonate, triethanolammonium lauryl sulfate, disodium lauryl sulfosuccinate, cocodiethanolamide, and mixtures thereof, to attain an aqueous mixture of materials in said digester and subjecting said mixture to elevated temperatures and pressures over selected time periods so as to attain a reduction of pulping liquor requirements, a reduction of H-factor, a reduction of pulp material rejects and a reduction in digestion time, relative to pulping liquor requirements, H-factor, reject percentages and digestion time periods experienced in similar alkaline digestion processes without said digestive additive; and (c) displacing said aqueous mixture of materials from said digester in such a manner as to attain at least some paperboard pulp and spent pulping liquor.

Claim 23

A method of producing a paperboard pulp having a Kappa number in the range of about 30 to about 110 from a lignocellulosic material comprising: (a) feeding an amount of said lignocellulosic material to a digester capable of yielding a given amount of paperboard pulp; (b) adding a sufficient amount of an alkaline pulping liquor to said digester to attain a select liquor-to lignocellulosic material ratio therein, said pulping liquor including therein an amount up to about 10%, based on a 100% total weight basis of dry paperboard pulp being produced, of a digestive additive selected from the consisting of sodium alpha-sulfo methyl laurate, sodium xylene sulfonate, triethanolammonium lauryl sulfate, disodium lauryl sulfosuccinate, cocodiethanolamide, and mixtures thereof, to attain an aqueous mixture of materials in said digester and subjecting said mixture to elevated temperatures and pressures over selected time periods so as to attain a reduction of pulping liquor requirements, a reduction of H-factor, a reduction of pulp material rejects and a reduction in digestion time, relative to pulping liquor requirements, H-factor, reject percentages and digestion time periods experienced in similar alkaline digestion processes without said digestive additive; and (c) displacing said aqueous mixture of materials from said digester in such a manner as to attain at least some paperboard pulp and spent pulping liquor.