Abstract: Aqueous polyester dispersions are prepared by(a) condensing an aromatic dicarboxylic acid or ester with at least one diol to give a prepolymer having an acid number of from 2 to 8,(b) reacting the prepolymer with at least one molecular weight enhancer compound, e.g. trimellitic anhydride to give a polyester having an acid number of from 40 to 60, and(c) dispersing the polyester in an aqueous medium to form an aqueous dispersion by adding an aqueous mixture of ammonia and an amine in a molar ratio of from 10:1 to 1:10 to a melt of the polyester which has a temperature within the range from 150.degree. to 230.degree. C.,and are used as sizes for sizing filament warp yarns.

Abstract: A process for sizing staple fiber yarns by applying an aqueous sizing liquor which contains an alkaline earth metal salt of a copolymer containing from 90 to 30% by weight of acrylic acid and/or methacrylic acid and from 10 to 70% by weight of acrylonitrile and/or methacrylonitrile, which copolymer has a viscosity of from 50 to 1,000 cp in 15% strength aqueous solution at 85.degree. C., and drying the treated yarns. The sized films obtained are moisture-insensitive and have good heat stability.

Abstract: Fabrics of which the warp is sized with water-soluble polymers of acrylic acid and/or their alkali metal salts or ammonium salts, are desized by treating the sized fabric with from 30 to 300 percent by weight of water, based on the dry weight of the fabric, and separating the resulting size solution from the fabric. The recovered size solution can be directly re-used for sizing.