Patent GB-1151091-A (GB)
Title: Cord for Coating by Blowpipe Projection.
Inventor: CLEMENT RENE
IPC: C23C4/04
Filed: 1966-03-10
Abstract: 1,151,091. Cord for coating. COMMISSARIAT A L'ENERGIE ATOMIQUE and SOC. DE FABRICATION D'ELEMENTS CATALYTIQUES. 10 March, 1966 [11 March, 1965; 24 Feb., 1966; 24 Nov., 1965], No. 10633/66. Heading B2K [Also in Divisions B5 and C3] A cord for supplying a gun for projection of a powder constituted by one of more mineral substances, to be utilized with the production of a coating by atomisation in a current of hot gas, comprises a first paste forming the core of the cord constituted by the powdered mineral substance or substances, at least one binder, at least one element for regulating the plasticity of the paste, the resulting paste being homogenized and a second paste constituted by organic substances forming an organic film covering and protecting the first paste. The material for regulating the plasticity of the first paste may be at least one plasticizer or at least one diluent a part of which can be eliminated by drying, or it may be constituted by at least one plasticizer and at least one diluent of which part may be eliminated by drying. The second paste may contain an organic substance and a diluent for which at least part may be removed by drying. They may contain a small proportion of a liquid which is miscible with water and which has a very Jow vapour pressure at the drying temperature of the cord. The binder may be methyl cellulose, hydroxymethyl cellulose, hydroxyethylmethyl cellulose, carboxymethyl cellulose or a polymer such as polyvinyl alcohol or polymethacrylic acid. Aqueous gels or natural organic substances such as gum tragacanth, alginate or dextrin may also be used. Organic binders which cannot be dispersed or dissolved in water, but in organic solvent such as benzene, toluene or trichloroethylene may be used such as cellulose acetate, vinyl derivatives or rubber. The plasticity regulator may be glycerine, the esters of glycol or ditriethyleneglycol. The mineral substance may be alumina and it may be mixed with aluminium hydroxide. The proportion of organic binder with respect to the weight of mineral powder may be from 0.5 to 8%. The film which is intended to form a sheath for the cord is preferably constituted by an organic substance which is either soluble or which can be dispersed or converted to a gel in the presence of water. Exemplified are methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, and natural organic substances such as gum tragacanth, gum arabic or alginates. The cord may be manufactured by extrusion from a device consisting of an assembly of coaxial nozzles the first paste containing the mineral substance or substances being supplied to the inner nozzle and the second paste to form any organic film being supplied to the outernozzle. Alternatively, the two pastes may be disposed within a cylinder of an extrusion press the first paste containing a powder to be projected being located at the centre and the second paste which forms the organic film being located at the periphery and then extruding by compression and forcing both of the pastes through the extrusion nozzle.