Patent GB-310844-A (GB)
Title: Improvements in the production of differential effects on fabrics made of or containing organic esters of cellulose
IPC: D06M11/38
Filed: 1929-04-26
Abstract: 310,844. Lyons Piece Dye Works, (Assignees of Rivat, G.). May 1, 1928, [Convention date]. Printing processes.-The cellulose ester in selected portions of fabrics made of, or containing organic esters of cellulose, is saponified in the presence of a swelling agent for the cellulose ester. The swelling agent is preferably contained in a paste with the saponifying agent, and the paste is applied by means of engraved or embossed plates or rolls, or by brushing or spraying on to the fabric through stencils. Differential colour effects can be produced, for example, by treating the resulting fabric with a dyestuff, which possesses an affinity for the unsaponified cellulose ester, but little or no affinity for the reconstituted cellulose, or vice versa or by the simultaneous application of both of these classes of dyestuffs. Alternatively, a dyestuff which is capable of dyeing cotton or reconstituted cellulose may be incorporated in the saponifying paste and the fabric afterwards dyed, if desired, with a dyestuff having an affinity for the unsaponified cellulose ester. As saponifying agents there may be used any suitable alkaline material, such as sodium or potassium hydroxides, or carbonates in sufficient concentration to saponify the cellulose ester to a degree sufficient to reduce or destroy the affinity of the same for dyestuffs, which possess affinity for the cellulose ester. As thickening agents in the paste there may be employed, for example, British gum, gum arabic, gum tragacanth, or dextrin. The swelling agents are preferably soluble in or miscible with water, for example, pyridine, acetone, or an alkaline sulphocyanide. The fabric may be any suitable woven, knitted, or netted fabric, and may consist wholly of organic ester of cellulose, for example, cellulose acetate, formate, butyrate, or propionate, or may be a mixed fabric containing such organic derivatives of cellulose and other fibres such as natural silk or wool. Since silk or wool have affinities for dyestuffs different from those of organic esters of cellulose and cotton or reconstituted cellulose, the presence of these materials renders possible further cross-dyeing effects, while if the fabric also contains reconstituted cellulose or cotton yarns, the cellulose yarns will behave towards dyestuffs in the same manner as the saponified portion of the fabric, and there will be obtained the double effect of ordinary cross-dyeing of mixed fabrics and cross-dyeing of the printed reconstituted cellulose design. In an example, a woven fabric consisting wholly of cellulose acetate yarns is printed by means of an engraved roller with a saponifying paste comprising British gum, caustic soda, pyridine, and water, with the addition, if desired, of suitable cotton dyes, for example the indanthrene colours. The fabric is dried at ordinary temperatures and is then steamed, washed, and treated in a dyebath containing an SRA dye of any desired colour, which dyes the cellulose acetate but has little, if any, effect on the regenerated cellulose. The fabric is then given a finishing treatment, such as scouring or washing. A resist printing effect is thus produced on the fabric. The Specification as open to inspection under Sect. 91 (3) (a) refers to the employment of phenol as a swelling agent. This subject-matter does not appear in the Specification as acrepted.