Hoechst Aktiengesellschaft

Cassella Aktiengesellschaft

Walter Kamutzki

Karl-Heinz Keil

Manfred Marten

Peter Hentzschel

Dieter Wolf

Hans U Huth

The present invention relates to a process for recycling silicone-coated paper by disintegration and new formation of sheets, which comprises carrying out the disintegration in the presence of one or more salts of monophosphoric esters.

Process for recycling silicone-coated paper

Neutral sizing of base paper pulp in a conventional aqueous suspension at a neutral pH for the production of sized, acid-free base paper by internal sizing with the use of aqueous cationic copolymer dispersions having a minimum cation activity of 20 .mu.mol/g of solids, more than half of the cationic charge being located on the surface of the dispersion copolymer particles, in combination with polymeric retention aids, the weight ratio of the polymeric retention aid to the cationic dispersion copolymer preferably being 0.3:1 to 0.005:1, in a quantity of up to 2% by weight of cationic dispersion copolymer, relative to the dry weight of the raw cellulose fibers. The internal sizing is effected by intensive mixing of the neutral sizing agent components with the raw cellulose fiber suspension, with the proviso that either the polymeric retention aid is added first and the cationic plastics dispersion is metered in afterwards or the two agents are metered separately at the same time into the cellulose fiber suspension, if desired with the additional use of inert fillers, pigments, dyes and conventional auxiliaries, and by subsequent isolation of the acid-free base paper in the conventional manner, if appropriate as base paper webs or base paper boards, and drying of the internally sized neutral base paper. In the combination according to the invention with the polymeric retention aid, the cationic plastics dispersion surprisingly shows a synergistic increase of its internal sizing effect in the neutral pH range.

Neutral sizing agent for base paper stuff with the use of cationic

Aqueous solutions of polyamidoamine-epichlorohydrin resins and preparation and use thereof. A stable aqueous resin solution having a pH of not more than 7 and containing as the resin a water-thinnable polyamidoamine-epichlorohydrin resin (A) obtained by reaction of a water-thinnable basic polyamidoamine (B) comprising an acid component (B.sub.1) and an amine component (B.sub.2) with epichlorohydrin (C), the level of organically bound chlorine in the resin (A) being not more than 4% by weight. The present invention further relates to a process for preparing these products and to the use thereof in particular for increasing the wet strength of paper.

Aqueous solutions of polyamidoamine-epichlorohydrin resins, and

A water-soluble organic polybase which is useful for the cationization of asbestos-free, cellulose fiber filter media is prepared by reacting a mixture of a compound of the formula

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Dieburg, Germany

Walter Kamutzki