Patent GB-1180960-A (GB)
Title: Topsheets for Diapers and Diapers having such Topsheet.
IPC: A61L15/34
Filed: 1967-12-20
Abstract: 1,180,960. Coating. PROCTER & GAMBLE CO. 20 Dec., 1967 [20 Dec., 1966], No. 57932/67. Heading B2E. [Also in Divisions A3, B5 and D1] A diaper comprises a liquid absorptive pad and a top sheet of fibrous material, the surfaces of the fibres of at least part of which are both hydrophobic and oleophobic, and at least part of the outer face of the top sheet bearing a discontinuous film of an oleaginous moisture barrier material. In Fig. 1a the diaper comprises as top sheet a soft-feeling, porous web 12 with edges 12a folded underneath the pad 11 and secured to the lower face thereof with adhesive so as to enclose the exposed edges of the absorptive material which can comprise creped cellulose webbing, or an air laid felt. The lower face of the assembled pad and top sheet can be attached to a moisture impervious back sheet 11a. Along at least the central portion of the web is a discontinuous film of an oleaginous moisture barrier material which can be mineral oils, eg. medicinal white oils and petrolatum; animal oils e.g. lanolin, cod liver oil; vegetable oils e.g. soya bean, peanut, cotton seed, rapeseed, olive, palm and coconut oil. An additive may be admixed with the oleaginous material e.g. a mineral oil can be mixed with a crystalline material such as triglycerides of higher fatty acids such as stearic, palmitic and oleic acids, zinc oxide, metal salts of fatty acids having molecules containing between 12 and 22 carbon atoms to increase its viscosity. Preferably the discontinuous film comprises a multiplicity of discrete droplets. The web 12 can be constructed of paper or a woven, knitted or non-woven fabric e.g. a non-woven fabric comprising rayon fibres bonded with cross-linked polymers of ethyl acrylate. The hydrophobic and olophobic surfaces of the fibres may result from a coating of oil- and water-repelling fluoro chemicals, silicones and fatty wax-like derivatives such as a pyridinium acid chloride derivative of stearamide. Examples of fluoro compound are acrylates and methacrylates of hydroxyl compounds having highly fluorinated residues, and their polymers and copolymers; chromium coordination complexes of saturated perfluoromonocarboxylic acids; perfluoro-ethers; perfluoro-alkanoic acids; fluorocarbon sulphonyl acrylamides and methacrylamides and their polymers; perfluoroalkyl sulphamidoalkyl esters of phosphorus acids; copolymers of perfluoroalkyl carbamates and methylene. Apparatus for applying the discontinuous film of oleaginous moisture barrier material comprises (Fig. 3) a cylindrically-shaped screen member 16 rotated through a pool 17 of such material and delivering the material to an application position A at a substantially constant rate. The screen member 16 comprises a multiplicity of rings 18 axially aligned and spaced from one another and has a covering of wire fabric 20. The screen member 16 is freely supported on two spaced driving rollers 24 covered by a layer 28b of elastomeric material. Extending axially within the screen member 16 in a position adjacent the application position A thereof is an air nozzle 34 which presents a slot extending full length of the screen member 16. The slot is formed by the adjacent lips of adjustable pipes 38. The interior of the nozzle 34 communicates through an air supply pipe with a source of pressurized air. A continuous length of the hydrophobic-oleophobic treated web 12 is located above the screen member 16 moving at constant speed and passing adjacent the application station A. As the screen member 16 revolves, a film of the material comprising pool 17 is picked up on the fabric 20 and carried to the application station A at which point the air jet from a nozzle 34 blows the material from the fabric onto the adjacent surface of the web 12, thereby forming the discontinuous film 14.