Patent GB-804852-A (GB)
Title: Non-woven fabric and process for forming same
IPC: D04H1/62
Filed: 1955-04-01
Abstract: 804,852. Agglutinated fibrous sheet materials. CHICOPEE MANUFACTURING CORPORATION. April 1, 1955 [April 1, 1954], No. 9589/55. Class 140. A method of forming a non-woven fabric from a loosely assembled fibrous web comprises distributing dry particles of adhesive material in a predetermined pattern in the web by means of streams of the particles striking the web in the pattern, softening the particles in the web to an adhesive state in contact with the fibres with the application of pressure thereto and hardening the particles to band the fibres together. The fibres may be of cotton, asbestos, glass, jute, wool, regenerated cellulose or cellulose derivative polyamides, polyesters, polyvinylchloride, polyvinylidene chloride and regenerated protein. Suitable binders include polyvinyl chloride, polyamides, polythene, cellulose acetate, polystyrene, alkyds and urea-, phenol- and melamine-aldehyde condensation products. Webs may be formed by a woollen or cotton card or a garnetting machine, as by air-laying. The adhesive particles may be electrostatically charged and may be distributed in the web by means of electric lines of force. The adhesive may be thermoplastic or solvent-activated. In the latter case the solvent may be applied by passing the web through a fog chamber. The method may be performed by means of apparatus comprising a carrier for the particles, means for giving the particles an electrostatic charge, a further carrier for the web adapted to bring the web into close proximity with the particles on the first-mentioned carrier and means for providing electrostatic lines of force arranged in the predetermined pattern in the area of proximity whereby the particles are transferred from the first-mentioned carrier to the web. As shown, a supply of solvent-activatable adhesive in particle form is fed from a hopper 11 on to a continuously moving belt 12 whereby it is carried over guide roller 17 and beneath an electrode 18 which charges the particles. A web 19 of loosely assembled fibres is led over a guide roller 21 and partially around a distribution drum 22 comprising a thin cylindrical outer wall 23 and an inner shell 24 containing uniformly spaced spikes 25 extending from its surface. The outer wall is made of a dielectric material while the inner shell and spikes are of a conducting material. The spikes cut as individual electrodes for defining electric lines of force designed to distribute the binder particles in the web in the pattern desired and they are arranged according to this pattern. Situated beneath the belt 12 is an electrode 27 with comb-like teeth 28 extending the width of the web. The web 19 moves at the same linear speed as the belt past the electrode 27. The latter is connected in circuit with electrodes 25 and a high potential is applied between them such that the comb 28 is charged with the same sign as the particles, and the spikes 25 with the opposite sign, whereby electric lines of force are set up which cause the charged particles of adhesive to be transferred from the belt to the web. The residue of particles is removed from the belt by cleaning brush 31. As drum 22 rotates, web 19, containing the adhesive particles arranged according to the desired pattern, is transferred to conveyer belt 36 whereby it is conveyed through spray chamber 42 containing solvent in the form of a fog for activating the adhesive. Belt 36 with web 19 thereon leave the spray chamber and enter the nip of pressure rollers 45, after which the web and belt separate and the web passes through the nip of a second set of pressure rollers 47. Thereafter the web may pass over conventional textile drying cans (not shown) and finally it is rolled up.