Papermaking additive

A retention and strengthening papermaking additive, comprising a partially deacylated microbial biomass of a polymer or oligomer carbohydrate units chemically bound to glucosamide units;

• said partially deacylated biomass containing 6 to 25%, by weight, of the biomass, of non-deacylated glucosamide units and glucosamine units derived from deacylation of glucosamide units of said polymer or oligomer, and 94 to 75% by weight of the biomass, of said carbohydrate units and said carbohydrate units being chemically bound to said glucosamine units and any non-deacylated glucosamide units, the partial deacylation of the biomass being from 35 to 80% deacylation;
• wherein amino groups of at least one polymer of said biomass are cross-linked with epichlorohydrin.

A process of producing a retention and strengthening papermaking additive comprising deacylating part of the glucosamide units of a microbial mass of a polymer or oligomer having both carbohydrate units and glucosamide units to form glucosamine units from glucosamide units, such that carbohydrate units remain chemically bound to said glucosamine units and non-deacylated glucosamide units, with dissolution of the mycelium of the microbial mass in an aqueous vehicle of the additive, the partial deacylation of the biomass being from 35 to 80% deacylation, and wherein said glucosamine units and non-deacylated units comprise 6 to 25% by weight of the biomass and the carbohydrate units comprise 94 to 75% by weight, of the biomass.

In a method of making paper from a pulp fibre papermaking furnish by adding to the furnish an additive system to promote retention of fines and fillers with the pulp fibres and to increase the strength of finished paper or paperboard, the improvement wherein the additive system comprises a retention and strengthening papermaking additive comprising a partially deacylated microbial biomass of a polymer or oligomer having carbohydrate units chemically bound to glucosamide units, and the dissolved mycelium of the microbial biomass, in an aqueous vehicle,

• said partially deacylated biomass containing 6 to 25%, by weight, of the biomass, of non-deacylated glucosamide units and glucosamine units derived from deacylation of glucosamide units of said polymer or oligomer, and 94 to 75% by weight of the biomass, of said carbohydrate units and said carbohydrate units being chemically bound to said glucosamine units and any non-deacylated glucosamide units, the partial deacylation of the biomass being from 35 to 80% deacylation.

A paper comprising pulp fibres and a retention and strengthening papermaking additive consisting essentially of a partially deacylated microbial biomass of a polymer or oligomer having carbohydrate units chemically bound to glucosamide units,

• said partially deacylated biomass containing 6 to 25%, by weight, of the biomass, of non-deacylated glucosamide units and glucosamine units derived from deacylation of glucosamide units of said polymer or oligomer with dissolution of the mycelium of the biomass, and 94 to 75% by weight of the biomass, of said carbohydrate units and said carbohydrate units being chemically bound to said glucosamine units and any non-deacylated glucosamide units, the partial deacylation of the biomass being from 35 to 80% deacylation.

A papermaking stock comprising:

• an aqueous dispersion of papermaking components comprising papermaking fibers and a papermaking additive in an aqueous vehicle, wherein said additive is a retention and strengthening papermaking additive comprising a partially deacylated microbial biomass of a polymer or oligomer having carbohydrate units chemically bound to glucosamide units, and the dissolved mycelium of the microbial biomass,
• said partially deacylated biomass containing 6 to 25%, by weight, of the biomass, of non-deacylated glucosamide units and glucosamine units derived from deacylation of glucosamide units of said polymer or oligomer, and 94 to 75% by weight of the biomass, of said carbohydrate units and said carbohydrate units being chemically bound to said glucosamine units and any non-deacylated glucosamide units, the partial deacylation of the biomass being from 35 to 80% deacylation.

A method of enhancing retention of components of a papermaking stock in a paper sheet formed from said stock in papermaking, comprising:

• adding to said stock comprising an aqueous dispersion of papermaking fibers, a papermaking additive in an aqueous vehicle, wherein said additive is a retention and strengthening papermaking additive comprising a partially deacylated microbial biomass of a polymer or oligomer having carbohydrate units chemically bound to glucosamide units, and the dissolved mycelium of the microbial biomass,
• said partially deacylated biomass containing 6 to 25%, by weight, of the biomass, of non-deacylated glucosamide units and glucosamine units derived from deacylation of glucosamide units of said polymer or oligomer, and 94 to 75% by weight of the biomass, of said carbohydrate units and said carbohydrate units being chemically bound to said glucosamine units and any non-deacylated glucosamide units, the partial deacylation of the biomass being from 35 to 80% deacylation;
• and forming a paper sheet from said stock.

A method of producing paper comprising:

• forming a sheet from a papermaking stock comprising an aqueous paper-forming dispersion of papermaking components comprising papermaking fibers and a papermaking additive in an aqueous vehicle, wherein said additive is a retention and strengthening papermaking additive comprising a partially deacylated microbial biomass of a polymer or oligomer having carbohydrate units chemically bound to glucosamide units, and the dissolved mycelium of the microbial biomass,
• said partially deacylated biomass containing 6 to 25%, by weight, of the biomass, of non-deacylated glucosamide units and glucosamine units derived from deacylation of glucosamide units of said polymer or oligomer, and 94 to 75% by weight of the biomass, of said carbohydrate units and said carbohydrate units being chemically bound to said glucosamine units and any non-deacylated glucosamide units, the partial deacylation of the biomass being from 35 to 80% deacylation.