GB354233A - Improvements in or relating to the manufacture of ribbons, films and tapes, or straw-like products of cellulose derivatives - Google Patents

Abstract

The process of the parent Specification is modified by the employment of heat as well as pressure in the production of flattened products from a number of filaments of thermoplastic cellulose compounds such as cellulose acetate after they have been treated with a liquid having a solvent or softening action. Another modification comprises the addition to the solvent or softening liquid of a high boiling solvent or plastifier, the treated filaments being then transformed by the application of pressure into flattened products, the application of heat being then optional. The filaments to be coalesced may be fine or coarse, they may be in the form of artificial bristles, or straw, or in the form of narrow braids, tapes, or strips of fabric, or small tubes of knitted fabric. Filaments or straws may be converted into coalesced ribbons, tapes, or straws continuously with their production. The compound of cellulose employed may be cellulose acetate, formate, propionate, or butyrate, or methyl, ethyl, or benzyl cellulose. As coalescing liquid, acetone, ethylene dichloride and methyl or ethyl alcohol, or dichlorethylene and ethyl or methyl alcohol may be used. Triacetin, diacetin, dibutyl tartrate, or tricresyl phosphate are suitable high boiling solvents, or plastifiers. Organic cellulose derivatives may be dissolved in the solvent or softening liquid. The solvent liquid may be applied by means of wicks, rolls, rods, or by spraying, or immersion. The heating and pressure device may comprise a pair of nipping rollers between which the softened filaments are passed, and one or both of the rollers is heated internally by steam, hot water, or electricity. The rollers may have plain and smooth or engraved or fluted surfaces. The temperature and pressure conditions may be such as to produce a clear continuous product, or such that the outlines of the original filaments are still perceptible. Colour effects may be produced on the products by applying dyestuffs prior to, or with the application of the softening liquid, or after the filaments have coalesced to form the finished product. The dye may be applied intermittently to obtain different colour effects. Printing paste may be applied to the embossed or engraved rolls to obtain printed patterns such as floral designs. Delustred or opaque effects may be produced by subjecting the product to the action of water, alcohol, or steam. The delustring liquid may be a non-solvent which is added to the softening liquid. Delustring may also be obtained by incorporating a soluble metal salt such as a salt of barium, strontium, or calcium, to the filaments before coalescing, and then treating the flattened product with an agent which precipitates the metal in the form of an insoluble compound. High lustre and waterproof properties are obtained by pressing the products between smooth rollers having waxes such as carnauba wax or beeswax thereon. Non-thermoplastic filaments such as natural, silk, wool, cotton, and reconstituted cellulose, or metallized threads, or fine flat metal bands may be incorporated with the thermoplastic filaments prior to coalescence. Metallic effects may be obtained by incorporating bronze or aluminium or other metal powder. Striped or differential colour effects may be obtained by employing filaments of different colours. Examples of dyestuffs which may be dissolved in the liquid used for coalescing are 1,4 dimethyldiamino anthraquinone, rosaniline hydrochloride, or cresyl blue. If the dye is added separately from the softening liquid, it is dissolved in a liquid capable of penetrating cellulose acetate, such as mono-ethyl ether of diethylene glycol, benzene, or dichlorethylene. Specifications 297,848, [Class 15 (ii), Dyeing, Processes &c. for], and 313,451, [Class 2 (ii), Cellulose &c.], are referred to.ALSO:The process of the parent Specification is modified by the employment of heat as well as pressure in the production of flattened products from a number of filaments of thermoplastic cellulose compounds such as cellulose acetate, after they have been treated with a liquid having a solvent or softening action. Another modification comprises the addition to the solvent or softening liquid of a high-boiling solvent or plastifier, the treated filaments being then transformed by the application of pressure into flattened products, the application of heat being optional. The filaments to be coalesced may be fine or coarse, they may be in the form of artificial bristles, or straw, or in the form of narrow braids, tapes, or strips of fabric, or small tubes of knitted fabric. Filaments or straws may be converted into coalesced ribbons, tapes, or straws continuously with their production. The compound of cellulose employed may be cellulose acetate formate, propionate, or butyrate, or methyl ethyl, or benzyl cellulose. As coalescing liquid, acetone, ethylene dichloride, and methyl ethyl alcohol or dichlorethylene and ethyl or methyl alcohol may be used. Triacetin, diacetin, dibutyl tartrate, or tricresyl phosphate are suitable high-boiling solvents, or plastifiers. Organic cellulose derivatives may be dissolved in the solvent or softening liquid. The solvent liquid may be applied by means of wicks, rolls, rods, or by spraying or immersion. The heating and pressure device may comprise a pair of nipping rollers between which the softened filaments are passed, and one or both of the rollers is heated internally by steam, hot water, or electricity. The rollers may have plain and smooth or engraved or fluted surfaces. The temperature and pressure conditions may be such as to produce a clear continuous product or such that the outlines of the original filaments are still perceptible. Colour effects may be produced on the products by applying dyestuffs prior to, or with the application of the softening liquid, or after the filaments have coalesced to form the finished product. The dye may be applied intermittently to obtain differential colour effects. Printing paste may be applied to the embossed or engraved rolls, to obtain printed matters such as floral designs. Delustred or opaque effects may be produced by subjecting the product to the action of water, alcohol, or steam. The delustring liquid may be a non-solvent which is added to the softening liquid. Delustring may also be obtained by incorporating a soluble metal salt such as a salt of barium, strontium, or calcium to the filaments before coalescing, and then treating the flattened product with an agent which precipitates the metal in the form of an insoluble compound. High lustre and waterproof properties are obtained by pressing the products between smooth rollers having waxes such as carnauba wax or beeswax thereon. Non-thermoplastic filaments, such as natural silk, wool, cotton, and reconstituted cellulose or metallized threads or fine flat metal bands may be incorporated with the thermoplastic filaments prior to coalescence. Metallic effects may be obtained by incorporating bronze or aluminium or other metal powder. Striped or differential colour effects may be obtained by employing filaments of different colours. Examples of dyestuffs which may be dissolved in the liquid used for coalescing are 1,4 dimethyldiamino anthraquinone, rosaniline hydrochloride, or cresyl blue. If the dye is added separately from the softening liquid, it is dissolved in a liquid capable of penetrating cellulose acetate such as mono-ethyl ether of diethylene glycol, benzene, or dichlorethylene. Specifications 297,848, [Class 15 (ii), Dyeing, Processes &c. for], and 313,451, [Class 2 (ii), Cellulose &c.], are referred to.