Abstract: Aqueous paper-sizing emulsions for bulk and surface sizing with a content of fatty acid anhydrides are described in which the fatty acid anhydrides are derived from unsaturated or saturated fatty acids or their mixtures with chain lengths of C12-C24 and are liquid under 50° C. The paper sizing emulsions additionally may contain another reactive or non-reactive sizing agent and/or a fixing agent containing aluminum ions. The new emulsions are suitable for the finishing of paper and cardboard.

Abstract: A method for preparing a paper sizing agent which has improved retention on paper and which is an aqueous dispersion stabilized with a polymer, including the steps of (a) dispersing a resin which is one of a colophonium resin or a compound derived from a colophonium resin in water containing a synthetic emulsifier present in an amount which is a minimal amount effective to prepare a metastable dispersion of the resin so that impairment of sizing action by the synthetic emulsifier is minimized; (b) immediately cooling the metastable dispersion to a cooled temperature; and (c) reacting the metastable dispersion while at a cooled temperature with a polymer which is one of a polymer solution or a polymer dispersion to form a stable dispersion, wherein direct dispersion of the polymer with the resin is avoided.

Abstract: An air entraining agent based on rosin for a composition which contains cement and which is one of mortar or concrete includes at least one rosin salt which is a reaction product of materials including rosin and from 0.

Abstract: Heat-stable polyimides and polyamideimides with modified benzhydrol structural elements and a process of preparing thereof; wherein the polyimides and polyamideimides are obtained by reacting 3,3'4,4'-benzhydroltetracarboxylic acid dimethyl ester a) with only a diamine and then cyclized to give polyimides or b) with a diamine and with trimellitic, phthalic-or isophthalic acid (or the anhydrides, acid chlorides, anhydride chlorides or esters) and is then cyclized to give polyamideimides.

Abstract: Soluble and/or fusible polyimides or polyamidoimides of the general formula I ##STR1## in which R denotes a divalent radical of the formula II ##STR2## Ar denotes trivalent or tetravalent aromatic radicals or mixtures thereof, X denotes the amide radical, if Ar is trivalent, and if Ar is tetravalent denotes the imide radical and R.sub.1 denotes divalent aromatic radicals, and a process for their preparation.

Abstract: Aromatic tetracarboxylic acids or derivatives thereof of the general formula I ##STR1## in which R denotes a divalent radical of the formula II ##STR2## Ar denotes tri- or tetravalent aromatic radicals or mixtures thereof, X, if Ar is trivalent, denotes an amide radical, and if Ar is tetravalent denotes an imide radical, and Y and Z either together denote the anhydride radical --CO--O--CO-- or by themselves and independently of one another denote the radicals --COOH, --COCL or --COOR.sub.1, and a process for their preparation.