Improvements in or relating to the production of ribbons, straws and like products of cellulose derivatives

摘要

For the manufacture of delustred artificial straw, ribbons &c from cellulose acetate and other thermoplastic derivatives of cellulose, a number of filaments rendered mutually adhesive by a solvent or softening agent are caused to coalesce by applying heat and pressure, and to either or both faces of the ribbon so formed a further quantity of solvent is applied and the ribbon raised to a temperature substantially above the boiling point of the solvent so as to cause its ebullient evaporation whereby superficial irregularities are produced on the ribbon. To secure the desired delustring, the straw should be heated to a temperature at least 15 DEG C. above the boiling of the solvent, for example, to 85--95 DEG C. when acetone is employed. The solvent liquid may contain a plasticiser for the cellulose derivative, or a cellulose derivative may be dissolved therein. The filaments to be coalesced may be of fine or coarse denier, twisted in the form of yarn or untwisted, or associated as braids, tapes, strips or tubes of fabric, or they may be artificial bristles or straw. If colour or ornamental effects are desired, the filaments may be dyed, or dye may be dissolved in the coalescing liquid, or there may be associated with the filaments other yarns, metal strips, metallized threads; or bronze powder &c. may be incorporated with the filaments to be coalesced. The delustring treatment may be combined with a further pressing of the straw to a greater width. Two or more pressure rolls may be employed; or the associated filaments or straw may be passed round one of a single pair of rolls and two or more smaller rolls may be caused to bear on such roll. By using heavy yarns and repeated pressings, films up to 6 in. or more in width may be made. In a specific modification of the process, coalescing and delustring are carried out simultaneously, 80 per cent of acetone being applied to the filaments which are passed through heated pressure rolls, the lower at a temperature of 85--90 DEG C. Specifications 313,451, [Class 2 (ii)], 368,738, and 371,428 are referred to.