Abstract: A photographic base paper in which the resin coating contains a stabilizer of formula, ##STR1## wherein R.sup.1 is a sterically hindered hydroxyphenyl R.sup.2 is C.sub.1 -C.sub.12 alkyl, and x is 1 to 4, or a metal salt of the corresponding phosphonate anion.

Abstract: A solid fibre reinforced plastics material sheet comprising 20% to 60% by weight of reinforcing fibres having a high modulus of elasticity (as herein defined), a substantial proportion of the fibers being between 7 and 50 millimeters long and 13 microns or less in diameter, and 40% to 80% by weight of a thermoplastics material.

Abstract: Pressure- or heat-sensitive record material carries hydrated zirconia as a color developer material. The hydrated zirconia may be modified by the presence of compounds or ions of one or more multivalent metals. The record material may be made by forming an aqueous dispersion of hydrated zirconia, either formulating the dispersion into a coating composition and applying the coating composition to a substrate web or introducing the dispersion into a paper making stock and forming a paper web which incorporates hydrated zirconia as a loading, and drying the resulting coated or loaded web to produce the record material.

Abstract: In the formation of a paper web from stock fed to a Foudrinier wire, the Zeta Potential is an important parameter. A measure of Zeta potential is made by measuring the streaming potential developed in a vertically-arranged cell having a horizontal mesh therein on the underside of which a pad of fibres and fines is formed by pumping stock into the lower part of the cell. Electrodes located in the cell above and below the pad are used to obtain a measure of streaming potential at a given pressure differential across the pad. A pressure transducer is mounted in the lower part of the cell. Corrections are made for temperature and conductivity by sensors in the stock feed path to the cell. A microprocessor control and measuring circuit is disclosed which sequences valves for controlling the flow of stock and flushing fluid to the cell and which measures the relevant parameters.

Abstract: Resin coated papers having improved properties especially edge penetration are made using an alkyl ketene dimer neutral size, a wet strength resin and an anionic polyelectrolyte to control the streaming potential of the papermaking stock during manufacture of the paper. Advantageously a supplementary size especially an epoxidized fatty acid amide is also used.

Abstract: A color developer for use in a pressure- or heat-sensitive record material comprises a particulate composite having as components hydrated zirconia and at least one of hydrated silica and hydrated alumina.

Abstract: Apparatus for spark perforation of sheet material comprising spaced apart first and second electrodes which define between them a sparking zone through which sheet material to be perforated can be moved in a predetermined direction, and in which the portion of the first electrode which is nearest to the nearest portion of the second electrode is located between an overlap position upstream of the second electrode in the direction of movement of the sheet by a distance of 1 mm and an offset position also equal to 1 mm in the direction of movement of the sheet, and means for guiding the sheet through the sparking zone along a path closer to said second electrode than said first electrode.

Abstract: Pressure- or heat-sensitive record material carries hydrated zirconia as a color developer material. The hydrated zirconia may be modified by the presence of compounds or ions of one or more multivalent metals.

Abstract: A color developer for use in a pressure- or heat-sensitive record material comprises a particulate amorphous hydrated silica/hydrated alumina composite in which the hydrated silica and hydrated alumina are chemically bound and in which the mean alumina content on a dried weight basis is up to 7.5%, based on the total weight of silica and alumina. The composite may be metal-modified, e.g. with copper.

Abstract: An instrument for measuring surface characteristics based on the opacity of a material has an optical projection system for illuminating a sample and photocell arrangement for measuring light reflected from the sample. The instrument contains standard black and white surfaces with reference to which the sample opacity is measured. The photocell signal is digitized and the results processed and calculations made by a microprocessor system enabling sets of results to be stored and mean and standard deviations to be calculated. The instrument is particularly intended for testing paper and, in connection with carbonless copy paper, enables a measure to be made of the density of an imprint relative to the background that is called calender intensity.

Abstract: A spark perforation apparatus includes a rotary electrode assembly for effecting spark perforation of sheet material passing between the electrodes of the assembly and a suitably juxtapositioned earthed surface. The electrode assembly comprises a first set of annular electrodes for connection to a suitable power source, a second set of annular electrodes alternating with and of greater external diameter than the electrodes of the first set, and dielectrical material spacing the electrodes so as to form a series of parallel capacitors.

Abstract: A color developer for use in a pressure- or heat-sensitive record material comprises a particulate amorphous hydrated silica/hydrated alumina composite in which the hydrated silica and hydrated alumina are chemically bound, in which hydrated silica predominates, in which the mean alumina content on a dried weight basis is at least 7.5%, based on the total weight of silica and alumina, and in which the surface area is below 300 m.sup.2 g.sup.-1. The composite may be metal-modified.

Abstract: A jet of liquid (3) is deposited from a reservoir outlet (2) on to a moving surface (4) located below the outlet. Deposition is effected by discharging a jet of the liquid on to the underside of a curved guide member (5) which is disposed between the outlet and the moving surface and which is oriented so as to cause the liquid to flow down the member on its underside so that its direction of flow approaches the direction of travel of the moving surface.The invention is particularly advantageous in the production of paper webs, especially multi-layer paper webs on a Fourdrinier paper-making machine.

Abstract: Potassium hydroxide or another alkaline potassium compound is used to adjust the pH of an aqueous color developing clay coating composition in the manufacture of color developing material for use in pressure-sensitive or similar copying systems. This reduces the decline in reactivity with time of such material and increases initial print intensity compared with conventional material in which the corresponding sodium compound is used for pH adjustment. Especially good results are obtained where the material being coated is a paper of high acidity such as results from rosin/alum sizing.

Abstract: In a process for the production of microcapsules containing a liquid fill material, a dispersion-stabilizing species is produced in an aqueous acidic medium by interaction of a melamine formaldehyde precondensate and a water soluble polymer, neither of which alone is dispersion stabilizing with respect to the liquid fill material, and the precondensate is condensed by acid catalysis to produce a condensate which separates from solution and enwraps the liquid fill material to produce microcapsules.

Abstract: A color developer for use in a pressure- or heat-sensitive record material comprises a particulate amorphous hydrated silica/hydrated alumina composite in which the hydrated silica and hydrated alumina are chemically bound, in which hydrated silica predominates, in which the mean alumina content on a dried weight basis is at least 7.5%, based on the total weight of silica and alumina, and in which the surface area is below 300 m.sup.2 g.sup.-1. The composite may be metal-modified.

Abstract: A color developer for use in a pressure- or heat-sensitive record material comprises a particulate amorphous hydrated silica/hydrated alumina composite in which the hydrated silica and hydrated alumina are chemically bound and in which the mean alumina content on a dried weight basis is up to 7.5%, based on the total weight of silica and alumina. The composite may be metal-modified, e.g. with copper.

Abstract: Apparatus for spark perforation of sheet material comprising spaced apart first and second electrodes which define between them a sparking zone through which sheet material to be perforated can be moved in a predetermined direction, and in which the portion of the first electrode which is nearest to the nearest portion of the second electrode is located between an overlap position upstream of the second electrode in the direction of movement of the sheet by a distance of 1 mm and an offset position also equal to 1 mm in the direction of movement of the sheet, and means for guiding the sheet through the sparking zone along a path closer to said second electrode than said first electrode.

Abstract: In an offset gravure web coating method and apparatus, coating composition is applied from a gravure roll to a transfer roll, thence to an applicator roll, and finally to the web. The web moves in the same direction as the applicator roll surface. The ratio of the speed of the applicator roll surface to that of the web is preferably not greater than 1:1. The method and apparatus afford improved coating patterns at low wet coatweights.

Abstract: Process and apparatus for controlling the deposition of a liquid on to a moving surface.A jet of liquid (3) is deposited from a reservoir outlet (2) on to a moving surface (4) located below the outlet. Deposition is effected by discharging a jet of the liquid on to the underside of a curved guide member (5) which is disposed between the outlet and the moving surface and which is oriented so as to cause the liquid to flow down the member on its underside so that its direction of flow approaches the direction of travel of the moving surface.The invention is particularly advantageous in the production of paper webs, especially multi-layer paper webs on a Fourdrinier paper-making machine.