| 摘要 |
A carded web or webs of fibre are treated with an aqueous dispersion of rubber, gutta, balata, or the like, either naturally occurring or artificially obtained and vulcanized or not, a coagulant is applied to the surfaces of the single web, or the outer surfaces of a number of superimposed webs, and the whole consolidated by pressure. The coagulant on the outer surfaces prevents sticking to the press, and may be applied by the press plates, belt &c. The dispersion is preferably applied by spraying, the direction of the spray being such that the fibres do not tend to be displaced, and it should be of such a nature that it coagulates well under pressure and drying, and should yield a rubber &c. of small extensibility. According to an example, a face sheet is laid on a belt or drum and wiped with 5 per cent acetic acid, a carded cotton web is sprayed with a mixture of 100 parts of rubber as 60 per cent latex, 3 parts of sulphur, 5 parts of zinc oxide, 0.75 parts of accelerator, and 15 parts of lamp black: the web is placed treated side down on the face sheet and the other side is sprayed: 5 more sprayed webs are superimposed, and finally an acetic acid coated face sheet is applied, and the sheet is rolled under increasing pressure, dried and vulcanized. Specifications 219,635 and 290,313, [both in Class 70], are referred to.
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