Abstract: A method of coating sheet material with a coating composition comprising particulate solid material suspended in a liquid carrier, wherein the coating composition is applied to the sheet material as a foam and subsequently dried, the air content of the foam being such that the viscosity of the coating composition is greater in its unfoamed state than in the foamed state in which the composition is applied.

Abstract: Apparatus for making a fibrous element includes an elongate foraminous former provided by at least one foraminous belt, with a foraminous forming chamber through which said belt passes and which is formed to a hollow shape thereby. The belt is driven through the forming chamber, and fluid is extracted in a fluid extraction zone which surrounds at least part of the forming chamber and formed by a closed drainage casing. An injection nozzle injects a fibrous dispersion into the former within said forming chamber with the injection nozzle being dimensioned so as to substantially exclude the ingress of air around an interface with the walls of said belt so that the apparatus produces an elongate fibrous element having an outer core of greater density than the inner core which it surrounds.

Abstract: Self-contained pressure-sensitive copying material having a coating which contains both a particulate mineral color-developing material and microcapsules enclosing a solution of a colorless color former which is reactive with the color developing material to produce a colored product, in which the particles of color developing material (e.g. an acidic clay) and optionally the microcapsules as well, are chemically treated with a protective agent to inhibit premature color development wherein the protective agent may be a self-crosslinkable polymer, such as an aminoplast polymer (e.g. a urea-formaldehyde or melamine-formaldehyde polymer), or an epichlorohydrin polymer (e.g. an aminoepichlorohydrin or an amide/aminoepichlorohydrin polymer), or an anionic surfactant (e.g.

Abstract: Sheet material having a polymeric surface for receiving a photographic image, the material comprising an antistatic agent which is a synthetic hectorite clay having a layered structure the layers of which are electrically charged.

Abstract: A process for continuously forming a fibrous element in an elongate closed foraminous former during movement of the former through fluid extraction means, and which includes the steps of forming a fibrous dispersion, injecting the dispersion into said former, generating a pressure gradient across an extraction zone within said fluid extraction means and injecting the fibrous dispersion into the former at an injection velocity relative to the speed of the former (efflux ratio) to cause some of the fibres to build up as a fibrous mat on the inner surface of the former and the remainder to pack together to form a core so as to produce a continuous fibrous element having a fibrous core which is enclosed by a crust of greater density.

Abstract: A method of producing self-contained pressure-sensitive copying material having a coating which contains both a particulate mineral color-developing material and microcapsules enclosing a solution of a colorless color former which is reactive with the color developing material to produce a colored product, in which the particles of color developing material (e.g. an acidic clay) and optionally the microcapsules as well, are treated with a protective agent to inhibit premature color development. The protective agent may be a self-crosslinkable polymer, such as an aminoplast polymer (e.g. a urea-formaldehyde or melamine-formaldehyde polymer), or a epichlorohydrin polymer (e.g. an aminoepichlorohydrin or an amide/aminoepichlorohydrin polymer), or an anionic surfactant (e.g.

Abstract: A layboy mechanism for the continuous stacking and delivery of batches of sheet material received from a delivery mechanism and comprising means for continuously receiving cut sheets and forming them into a downwardly moving stack, divider means for dividing the stack into batches containing a predetermined number of sheets, and means for removing the lowermost batch while the remainder of the stack above it is supported by auxiliary support means which move between an operative support position and an inoperative position clear of the stack.

Abstract: A fibrous element comprising an elongated structure having a fibrous core with the fibres arranged in random orientation, said core being stiffened and enclosed by a fibrous crust integral with the core and formed as a surface layer of greater density.

Abstract: A method of encapsulating finely divided particulate material, such as minute droplets of a water-immiscible liquid, to produce microcapsules in which the particulate material is surrounded by polymeric shells, comprising the steps of forming a dispersion of the particulate material in an aqueous medium containing a water-soluble ureaformaldehyde precondensate, a water-soluble melamineformaldehyde precondensate and a water-soluble polymer which is capable of being cross-linked by said precondensates, and condensing said precondensates by acid catalysis with resultant cross-linking of the polymer about the particulate material so as to form the polymeric shells. The polymer may be a cellulose derivative, starch, a starch derivative, a polyacid, a polyester, a polyanhydride copolymer, a polyacrylamide or a polyacrylamide copolymer, and is preferably an acrylamide/acrylic acid copolymer.

Abstract: Paper for use in pressure-sensitive copying systems consists of a base paper one surface of which is machine glazed and the opposite surface of which is left rough due to expulsion of moisture during manufacture. Those sheets which are provided with a color reactant have the reactant applied to the glazed surfaces thereof and those sheets which are provided with a microcapsule coating have the microcapsule coating applied to the rough surfaces thereof.

Abstract: A smoothing roll for use with apparatus for coating a web of paper or other sheet material, particularly for smoothing coatings at low wet coatweights of silicone compositions applicable in their natural state without the use of a solvent, has a soft elastomeric covering the smoothing surface of which is pitted and is substantially impermeable to liquid coating compositions.

Abstract: Microcapsule coated sheet material for use in pressure sensitive copying systems is produced by a method which comprises forming an aqueous coating composition containing microcapsules, particulate stilt material and a biner, foaming the coating composition, applying the foamed composition to a web of sheet material, and metering the composition on the web to a desired coating weight by means of a metering member, for example a blade which preferably is flexible, in contact with the coating composition on the web. The foamed composition is preferably applied to the web by means of a fountain applicator.

Abstract: A coated transfer sheet for pressure-sensitive copying systems which comprises an organic colorless color former containing two or more potential chromophoric systems each of which is capable of being activated substantially immediately when the compound is brought into contact with one or more activating substances.

Abstract: In a method of making non-woven fibrous material such as paper, the papermaking stock as it is being delivered to the foraminous support of a papermaking machine has air under pressure introduced into it to produce foaming of the stock and the stock is subjected to turbulence. This is effected by providing the head-box of the papermaking machine with a slice the body of which includes a slot through which the stock flows to the foraminous support and which is shaped to impart turbulence to the stock. The body also includes an air supply passage which communicates with the slot to introduce the pressurised air into the stock.