Abstract: According to the present invention a dispersant is provided for stabilizing dispersions of metal oxides and/or carbon black in water in the presence of a hydrophilic binder. Said dispersant is a block-copolymer comprising at least one block of an ammonium group containing (meth)acrylate.

Abstract: According to the present invention a dispersant is provided for stabilizing dispersions of metal oxides and/or carbon black in water in the presence of a hydrophilic binder. Said dispersant is a block-copolymer comprising at least one block of an ammonium group containing (meth)acrylate.

Abstract: A surface-active block copolymer which comprises chemically linked polymeric blocks (A) and (B), block (A) of said copolymer consisting of at least one homo- or copolymerized non-polar alpha,beta-ethylenically unsaturated monomer and block (B) of said copolymer is derived by polymerizing an alpha-beta ethylenically unsaturated monomer containing an epoxy group and transforming the epoxy group into an hydroxy-substituted ionic group, preferably an anionic group. These block copolymers are used as dispersing agents in aqueous dispersions, including polymeric latex dispersions, and as plasticizing agent in hydrophilic colloid layers, including colloid layers containing a dispersed light-sensitive silver halide emulsion or other auxiliary substances for photographic materials.

Abstract: Fluorine-containing surfactants according to formula (Rf--X).sub.n --A--L--Z wherein Rf is a short-chain fluorine-containing group derived from hexafluoropropylene or trifluorochloroethylene, X is --O--, --S--, or --SO.sub.2 --, n is at least 2, the Rf groups being same or different, L is a monovalent bond or a bivalent bridging group such as --COO--alkylene, --CONR.sup.1 --alkylene, or --SO.sub.2 NR.sup.1 --alkylene, wherein R.sup.1 is hydrogen or C.sub.1 -C.sub.5 alkyl, and Z represents a hydrophilic polyoxyethylene group or a hydrophilic group such as ##STR1## wherein M is hydrogen, an alkali metal, ammonium, or organic ammonium, and R.sup.3 is alkyl; A is an aliphatic, aromatic, or aliphatic-aromatic group. These surfactants can be used in hydrophilic colloid layers, which may form part of light-sensitive silver halide materials.

Abstract: Hydrophilic coating compositions are made comprising a protective colloid and dispersed therein a matting agent. The matting agent is obtained by mixing in aqueous medium area, formaldehyde and an aqueous colloidal dispersion of silica. The mixture is buffered to keep the pH at 3.2 or lower. Urea and formaldehyde are polycondensed while vigorously stirring until particles comprising urea-formaldehyde resin and silica are formed of average particle size of 1-8 .mu.m. The rate of stirring is reduced and the pH is raised to 5 or higher to prevent afterpolycondensation and agglomeration of the polymer particles. A hydrophilic colloid is then dissolved in the reaction mixture.Photographic light-sensitive silver halide material incorporating a layer formed from the hydrophilic coating composition.

Abstract: A liquid toner developer composition suitable for use in developing electrostatic charge patterns, characterized in that the developer contains a metal alkyl sulphonate ionic surfactant in which the metal ion is a bivalent metal ion selected from the group consisting of zinc(II), lead(II), cadmium(II) and copper(II) and the sulphonate group thereof is present directly on an alkyl chain containing at least 6 carbon atoms in a straight chain, which sulphonate has a positive charging effect on the toner, and the sizes of the toner particles and the amount in which said sulphonate is present are selected such that the toner can develop a charge pattern having a charge level corresponding to 50 V for a capacitance of 1.5.times.10.sup.-11 F.cm.sup.-2 up to an optical density of at least 0.8.