GB997265A - Improvements in and relating to fibrous sheets, webs, fleeces and the like - Google Patents

Abstract

Fibrous material in the form of a sheet, web, fleece or the like contains regenerated cellulose fibres, in the preparation of which at least one substance activating a fibre-fibre bond has been added. This substance may confer acid, basic, anionic, cationic or contact-adhesive properties, may be a thermoplast or elastomer, and may swell strongly in water. Examples are ethylene diamine, polyethylene diamine, polyvalent acids or acid salts, polyacrylic acid, cellulose-glycollic acid, alginic acid, polyethyleneimine, condensates of formaldehyde with urea, guanidine, dicyandiamide or melamine, basic cellulose derivatives, natural or synthetic rubber, polymers and copolymers of acrylate esters and acrylamide, cellulose or starch derivatives, polyvinyl ethers, polyvinyl alcohols or mucilages. Hardeners such as formaldehyde or compounds which split off formaldehyde may be added. The activating substance may be added to the solution from which the fibre is spun, and the fibres are then cut to staple length, formed into a suspension and a sheet, web or fleece formed therefrom. Bonding occurs between the fibres containing the activating substances and fibres not containing it. The latter may be of regenerated or natural cellulose, wool, silk, inorganic fibres, polyamides, polyesters, polyacrylic compounds or polyvinyl compounds. A precipitating agent, e.g. aluminium sulphate may also be present. Alternatively there may be used: fibres of two different kinds containing different activating agents, e.g. oppositely charged or able to form bonds through secondary valencies; fibres of one kind only bonded by purely physical forces; or fibres of one kind bonded by a bridge-forming additive, e.g. a polyvalent base such as polyethylene diamine or ethylene diamine with acid-reacting fibres or a polyvalent acid with basic fibres.