| 摘要 |
Wool and other animal hairs, and intermediate and finished textile fabrics manufactured from them, are impregnated with an aqueous solution of a precondensation product of formaldehyde and resorcin or a substituted resorcin, the pH of the solution being from about 2.8-5. Filter cloth, woollen filter bags, woollen carpets, felt, and other animal hairs such as horse-hair may be treated. At least 6 gram-molecules of formaldehyde per grammolecule of the resorcin may be used, and the final condensation on the material may take place at a temperature of 100-140 DEG C. and preferably 100-110 DEG C. The pH of the solution before application to the material may be corrected if necessary by the addition of weak acids or alkalies, for example lactic acid. In one example, a mixture of formalin and resorcin is heated for 30 minutes to 60 DEG C., cooled and water added. Wool fibres are placed in a bath of this solution and after 30 minutes the wool is centrifuged, dried at 70 DEG C., and finally heated for 30 minutes at 105 DEG C. 1.3-Dihydroxy-6-chlorobenzene may be used instead of resorcin. By this treatment the material is softened and made more resistant to acids and alkalis, its tensile is strength improved, and shrinkage is decreased. Specification 649,974 is referred to. |
