Abstract: Dispersions of titanium dioxide in various media have been known but there has been an increasing demand for the use of titanium dioxide as an absorber for UV light while remaining substantially transparent to visible light. Hitherto it has not been practical to prepare a high solids content oil dispersion of such material having an extremely high maximum extinction coefficient in the ultra violet range of wavelengths.Such a dispersion has now been developed in an oil of particles of titanium dioxide having an average size from 0.01 to 0.15 micron and an organic dispersing agent in which dispersion the amount of said particles are such that the dispersion has a solid content greater than 40% by weight. The dispersion has a maximum extinction co-efficient in the ultra violet range of wavelengths of at least 40 liters per gram per cm.

Abstract: An article is provided which has a surface which is contactable in use with water at a temperature of at least 100.degree. C. The surface of the article is protected from attack by the water, because it is formed of a shaped fired ceramic material which is formed from particulate zirconia having a coating on the particles thereof of a hydrous oxide of yttrium and optionally also a hydrous oxide of zirconium, titanium or aluminum. Preferably the particles have a diameter of not more than 0.5 micron and the amount of hydrous oxide of yttrium falls within the range 0.5 to 10 mole percent as Y.sub.2 O.sub.3 on moles of zirconia. Typical articles are internal combustion engines and parts thereof, mills and impact plates therefor, and pump surfaces. Fuel cells are also described.

Abstract: A process for the manufacture of core/shell polymer particles comprises forming a core particle containing acid functionality, a first shell around said core of a copolymer of a nonionic monoethylenically unsaturated aromatic monomer and a copolymerisable polar monomer in an amount of at least 15% by weight of the copolymer and having a solubility in water at 20.degree. C. of at least 1% by weight and a second shell around said first shell of a polymer or copolymer of a nonionic monomer having a solubility in water at 20.degree. C. of less than 1% by weight and swelling the particle with a non-volatile alkali to generate one or more vesicles.Preferably each shell contains a polymer or copolymer of styrene.

Abstract: A new process for the production of pigments suitable for use in paper laminates has been developed in which a metal oxide is treated with a water-soluble salt of zinc and a phosphate or phosphoric acid and subsequently with an alkali metal aluminate in such a manner that there is deposited on the metal oxide a coating containing zinc and phosphate ions together with aluminium ions. The pH of the dispersion following the metal oxide is maintained at a value not exceeding 8.0 during precipitation. A particularly useful pigment is produced which has a coating containing zinc ions in an amount of 0.5 to 5% by weight as ZnO, phosphate ions in an amount of 0.2 to 3% as P.sub.2 O.sub.5 and aluminium ions in an amount of 0.5 to 5% expressed as Al.sub.2 O.sub.3 on the weight of TiO.sub.2.

Abstract: An organometallic compound which is the reaction product of (a) a zirconium halide or oxyhalide, (b) a polyol and (c) an alpha-hydroxy acid is claimed. The preferred polyol is sorbitol and preferred alphahydroxy acids are citric, malic or lactic acid. The compounds find use as cross-linking agents in fracturing fluids employed in the hydraulic fracturing of oil or gas-containing subterranean strata. The claimed compounds can be used to produce a slow or delayed gel formation in such fluids.

Abstract: A composition suitable for use in the manufacture of a ceramic material comprises free-flowing substantially non-aggregated particulate zirconia. A substantial proportion of the zirconia is present in the tetragonal crystalline form and the particles of zirconia contain alumina in an amount of from 1 to 10% by weight expressed as Al on ZrO.sub.2. The particles are substantially free of silica.The particles of zirconia can be coated with an oxide or hydrous oxide of a stabilizing agent for zirconia such as an oxide or hydrous oxide of yttrium, calcium, magnesium, barium, strontium or cerium.An oxidation process is described for the manufacture of the tetragonal crystalline zirconia by the oxidation of zirconium halide in the presence of aluminium halide at high temperature in the vapor phase.

Abstract: A new titanium chelate has been developed which introduces improvements into aqueous emulsion paints. The chelate is a reaction product of a titanium orthoester, a glycol or a glycol ether, an alkanolamine and an alpha-hydroxy carboxy acid.

Abstract: An aqueous dispersion of acicular fine particle size titanium dioxide containing from 20 to 60% by weight solids content and a polycarboxylic dispersant is of outstanding use in the preparation of sun screens. The dispersions are transparent to visible light and absorbant to UV light of broad spectrum. Usually the titanium dioxide has a largest dimension within the range 0.01 to 0.15 micron.The dispersions are produced by milling, preferably in a high speed mill, until the required UV absorbancy is attained.

Abstract: Compositions suitable for use as a camouflage material are based on vesiculated granules of polymer material which are substantially free of titanium dioxide but contain a light reflecting agent. The agent is an oxide, hydroxide or insoluble salt of magnesium or an insoluble mixed salt of calcium and magnesium and is present in an amount of at least 10 percent by weight of the polymeric material. Preferably the agent is dolomite. Paints containing the composition are useful as camouflage in snowy conditions and the aqueous paints are removable by scrubbing.

Abstract: Polymer particles or beads for use as opacifiers in paints are described in which a core is provided with a hard sheath and the particle has one or more voids produced by reaction with a non-volatile permanent or fixed base. The sheath is a coploymer of an ethylenically unsaturated aliphatic monomer free of acid groups and at least 2 percent by weight of a soft ester-containing monomer and optionally styrene in an amount of up to 25 mole percent. The core is formed from an ethylenically unsaturated monomer with acid functionality.The sheath polymer has a glass transition temperature of at least 40.degree. C. The particles have a size of up to 40000 nanometers before swelling the core by some 150 to 2000 percent.

Abstract: A process of coating or encapsulating an inorganic powder is described in which the powder, preferably a pigment, is dispersed in an aqueous medium and an ethylenically unsaturated monomer is polymerized in the presence of the powder and while subjecting the reaction mixture to ultrasonic vibrations. The monomer is present in an amount not exceeding 200% by weight of the powder and preferably is an acrylate or methacrylate.The powder has a cationic charge on its surface which can be generated by treatment of the surface with, preferably an aluminium salt.

Abstract: Curable compositions comprise a silanol-terminated polyorganosiloxane, a cross-linking agent which is an organic silane free of isocyanate groups and a metal organic compound containing a Ti-O-P bond. The compositions cure on exposure to the atmosphere and, in comparison to known compositions containing organotitanium compounds show a reduced tendency to be discoloured.

Abstract: A new form of titanium dioxide has been developed in which the particles have a substantially rectangular cross-section with a width to length ratio of at least 0.8:1.0. A most desirable cubic form of anatase titanium dioxide is included. The products are formed by hydrolyzing a solution containing TiOCl.sub.2 species under autothermal pressure.

Abstract: A method for the production of a nitride of zirconium, hafnium, silicon, germanium, tin, lead, boron, aluminium, gallium, indium or thallium either alone or as mixtures is claimed. Ammonia and a halide of at least one of these elements are heated by means of a direct electric current plasma in a non-oxidizing gas in a reactor in which recirculation is induced such that the defined recirculation ratio is greater than 2.5 and preferably greater than 4.0. Any titanium halide present shall be less then 40% by weight of mixed halides.

Abstract: A method which comprises the manufacture of black titanium nitride which comprises heating ammonia and titanium halide by means of an electric plasma formed in a stream of non-oxidizing gas generated by the discharge of direct current electricty between a pair of electrodes. The heated gases are introduced through an inlet nozzle into a reactor so constructed and operated as to induce circulation of the gases with a specifically defined recirculation ratio.

Abstract: When it has been attempted to dry wet polymeric particles in hot air at up to 100.degree. C. it has tended to produce discoloration in the product, introduce aggregates into the product, reduce the dispersibility of the product and reduce the integrity of the surface of the particles. A process of drying has now been developed which comprises heating to an elevated temperature the wet particles in an atomsphere substantially free of oxygen gas so that substantially all of the moisture is removed from association with said particles and under such conditions of time and temperature that any substantial deterioration of said particles is minimized. Preferably the atmosphere is of nitrogen.

Abstract: A leather tanning agent for use as a sole tannage or with another includes Al (III) ions, Ti (IV) ions and an organic masking agent in specific proportions. The ratio of Ti:Al expressed as metal oxides TiO.sub.2 :Al.sub.2 O.sub.3 on a weight basis is from 0.6:1 to 2:1 and the amount of masking agent is from 0.1 to 0.4 mole per mole of total metal oxides. Preferably SO.sub.4 ions are present.Other metal tanning agents such as zirconium salts can be incorporated.The tanning agent finds wide use and has an increased stability.

Abstract: In a leather tanning process, animal skins are treated with a tanning agent comprising an aluminium (III)/titanium (IV) mixed complex with a salt of a polyhydroxymonocarboxylic acid as a masking compound. The masking compound preferably has the general formula:HOCH.sub.2 (CHOH)n CO.sub.2 Mwherein M is an alkali metal, and n is 2 to 6. Especially preferred masking compounds are sodium gluconate and sodium glucoheptonate. The same process can be used for a wide range of skins, both as a base tannage and in combination with other tanning processes.

Abstract: There is an increasing demand for products which are effective in the absorbancy of UV light but still remain transparent to visible light. Titanium dioxide has been proposed for this use.A new form of titanium dioxide has been developed which is very effective in use and which is acicular in shape and having a ratio of the largest dimension to the shortest within the range 8:1 to 2:1 and wherein the largest dimension is from 0.01 to 0.15 micron and in which the particles have a coating of a hydrous oxide of aluminium and of silicon in a weight ratio of at least 1.5 and not greater than 4.5 expressed as the oxides. The materials are eminently suitable for use in cosmetics and other skin care products.

Abstract: Swollen core/sheath polymeric particles are disclosed having one or more voids in the core formed by reaction with a base such as sodium hydroxide. The sheath contains styrene or similar monomer polymerized in an amount greater than 25 mole percent and the polymer is free of acid groups. The core contains acid groups. Swelling is effected at an elevated temperature and in the absence of an organic solvent.The swollen particles on drying in a paint or other composition have air in the voids and act then as opacifying agents.