GB234245A - Improvements in paper and processes of making the same - Google Patents

Abstract

234,245. Dicker, S. G. S., (Rubber Latex Research Corporation). April 7, 1924. Paper, treating with special materials; boards and compound paper; coated paper. - Paper, pulp board, and pulp articles are treated with a solution of latex stabilized in known manner as bv the use of ammonia or other alkali and then dried in such manner as to solidify the latex solids into a dried irreversible gel. A caoutchouc product is formed which is structureless and practically homogenous, quite distinct from tough and short coagulation rubber. Unsized or slightly sized paper from the rolls of the paper machine is passed through a bath of diluted latex, the excess is preferably removed by squeezing rolls and the paper dried by hot rolls. If thick paper is used, drying under vacuum or reduced pressure is desirable, in which case too early extraction of the ammonia, and the resultant acidity and coagulation of the latex must be avoided. A surface impregnation or a graded impregnation may be obtained on one or both sides by using paper more or less moist. Duplex wrapping paper may be produced by using a latex gel bond for two sheets. Where a clinging film of latex is left on the paper, the film, whilst tacky, may be used to secure a facing of finely-divided material such as china clay, soapstone, talc, '' agalmatolite," &c. The tackiness may be produced by a slight raising of the temperature of the paper. The void spaces left in the treated paper may be reduced either by repeated impregnation or by hot pressing to cause the rubber film to bond. Latex may be used with most alkaline sizing materials and also with some of a neutral character. A vulcanized product may be obtained by incorporating colloid sulphur with the latex mixture, or, better, by using ammonium sulphide or polysulphide as the stabilizing agent. Paper treated as above may be subsequently frictioned with rubber in the production of paper-covered fabrics. To facilitate impregnation, the paper may be moistened with either water, alcohol, ether or other volatile liquids. Rubber produced in paper according to this process contains somewhat more proteid or nitrogenous matter than ordinary rubber.