GB416077A - Improvements in or relating to the manufacture of materials of or provided with compositions of or containing rubber - Google Patents

Abstract

416,077. Coating webs. INTERNATIONAL LATEX PROCESSES, Ltd., 10, Lefebvre Street, St. Peter's Port, Guernsey, MADGE, E. W., and PAYNE, F. J., Fort Dunlop, Birmingham. March 9, 1933, No. 7140. [Class 140.] Materials of or containing rubber are produced in sheet form by introducing aqueous rubber dispersions into a nip formed by positioning two or more moving surfaces in such manner that coagulation commences on the introduction of the dispersions between the moving surfaces and proceeds thereafter and withdrawing the formed material through the nip. Such materials include sheeting, strips, coated fabrics, impregnated weftless cord fabrics, substitutes for cork, leather and linoleum (loose fleeced cellulose and rubber), and rubber backed carpets. The moving surfaces can be those of rotating rollers which may be rubber covered, or endless belts, and the nips can be formed between two or more of such surfaces or by introducing one or more moving lengths of fabric between two rotating rollers. The dispersions may be coagulated by providing the moving surfaces with coagulant or where heat sensitive dispersions are used, by heating them, or shear sensitive dispersions may be used. The gauge of sheet made with rollers is dependent upon the distance between them, and where coagulant is employed, upon its strength. Thick sheets for use in making golf ball tape and thread, can be obtained using heat sensitive dispersions, while with those sensitive to shear only thin sheets can be produced. Heat sensitizing agents include sodium and potassium silicofluoride, ammonium persulphate and reagents which mutually react on heating to produce coagulants, e.g. a mixture of zinc oxide and ammonium sulphate. The moving surfaces may be patterned to produce patterned surfaces or perforated material, or the finished material may be sprayed with e.g. waste wool or otherwise treated as in finishing artificial leather. In examples (1) weftless cord is rubberized by spreading a coating 4, Fig. 1, on the fabric 5, by means of a gauge 3 and passing the material between rollers 1 licked by a coagulant applied by rollers 2 ; (2) reinforced porous or microporous rubber articles are made by feeding between coagulant licked rollers one or more plies of carded cotton web impregnated with a bank of ebonite mixing maintained either between the web and rollers or between the webs themselves. The sheet may be stored before vulcanization in dilute acetic acid or in water and is vulcanized under conditions such that evaporation of the liquid contained in it is prevented. The web may be omitted to produce non-reinforced microporous rubber; (3) belting in several plies is made by passing duck 17, Fig. 4, between coagulant licked rollers 16, latex mixings 18 being fed between the webs and the rollers and webs. At each step the coagulant remaining on the outside of the coagulated rubber on the duck serves to coagulate the inner rubber layer for the next ply. The process may be used in addition to those noted above for impregnating felt, for double textured waterproofing material, for flooring material using impregnated hessian, and for brake linings using asbestos impregnated with an ebonite mixing. Specifications 219,635 and 290,313, [both in Class 70], are referred to.