| 摘要 |
In a process for the manufacture of films, bands, threads and similar articles from plastic compositions such as cellulose derivatives, resins, rubber, gum or gelatine, wherein the composition is spread on a supporting surface, e.g. a drum or endless band, to shape it and is then subjected to the action of an extraction agent to remove solvent materials, the extraction agent is heated and the support cooled to a temperature considerably below that of the agent, in the case of a gaseous extracting agent, and when a liquid is being used, the liquid is cooled and the support heated to a considerably higher temperature. In this way solidification is accelerated. The invention is particularly useful for the production of articles containing filling or other materials, which must have a higher boiling point than that of the solvent. Such substances may be added to the composition, or to the extracting agent from which they will be absorbed by the composition. In an example a solution of cellulose acetate in 80 parts of methylene chloride and 20 parts of ethyl alcohol is spread on a surface maintained at 15 DEG C. by means of a water jacket or otherwise. Air heated to 80--100 DEG C. is passed over the composition and after 5 or 6 minutes, the article may be removed from the support. In another example a solution of divinyl formal in a mixture of 90 parts of methylene chloride and 10 parts of alcohol is employed. In a third example a solution of nitrocellulose in methyl alcohol is spread on a drum immersed in water at about 4 DEG C. The drum is heated, e.g. by hot oil to 50 DEG C. The composition solidifies in less than 1 minute. The composition may be spread on a support at ordinary temperature, the support then being heated or cooled.ALSO:In a process for the manufacture of films, bands, threads, and similar articles from plastic compositions such as rubber compositions, wherein the material is spread on a supporting surface, e.g. a drum or endless band, to shape it and is then subjected to the action of an extraction agent to remove the solvent materials, the extraction agent is heated and the support cooled to a temperature considerably below that of the agent in the case of a gaseous extracting agent, and when a liquid extraction agent is being employed the liquid is cooled and the support heated to a considerably higher temperature. Solidification is thereby accelerated. The composition may be spread on a support at ordinary temperature, the support then being heated or cooled. |
