Dec. 31, 1946. 2,413,559 ‘R. c. GREENLEES DYEING OF FILMS POSSESSING LOW WATER IMBIBITION Filed 001;. 14, 1944 __ N; ,; , _ m N07.“ O 0. m1NIH v QC kWh ?zveni-or RAYMOND CRAWFORD GREEN LEES . 3y his ailarney; Patented Dec. 31, 71946 - ~' ' Y ' ' 2,413,559 UNITED STATES PATENT OFFICE DYEING OF FILMS POSSESSING‘L'OW WATER IMBIBITION ' Raymond Crawford Greenlees, Coventry, Eng land, assignor to Courtaulds Limited, London, England, a company of Great Britain ‘Application October 14, 1944, Serial No. 558,729 - In Great Britain December 13, 1943 ' 3 Claims. 1 2 This invention relates to the dyeing of ?hns pzsssessing low water i'mbibition‘ and is particu lrly' concerned with the dyeing of such ?lms in polymerised alkyl substituted acrylic esters such » a ‘lie (or jigger) dyeing machine, or a dyeing ,machine using the same principle. When dyeing material suchras fabric in a jig, the fabric, which has been-wound up on to one of the rollers ?xed above the‘ dyebath, is passed under a guide roller immersed in the dyebath '1 and rewound on to the second roller ?xed above the dyebath, the fabric being run forwards and ' - backwards from one roller to the other until the dyeing has proceeded to the desired extent. It is a characteristic of jig dyeing that as part of the dye liquor is taken up by the fabric during its passage through the dyebath, most of the dyeing takes place, not in the dyebath but whilst as polymerised methyl methacrylate. The proc ess of this invention is applicable to ?lms which in addition to any one or more of the above materials also contain plasticising or softening agents of the usual type such as dimethyl phthal ate, diethyl phthalate, dimethoxy'ethyl phthalate, dibutyl vphthalate, methyl and ethyl phthalyl ethyl g-lycollates, dimethyl, tartrate, diethyl tar trate,_'triphenyl phosphate, tricresyl phosphate, diacetin, tri'acetin and trichlorethyl phosphate.. ,1 Thefabric 'shouldpreferably be one which has very little or no a?inity for the ,dyestuif being employed in any particular instance. For exam ple, when dyeing cellulose acetate ?lm with a dispersed dyestuff such as Duranol Violet 2 R 300 (Imperial Chemical Industries Limited) a cotton the fabric is Wound up on the rollers, When jig or a viscose rayon fabric is suitable. dyeing is applied to ?lms of a thermoplastic ma When dyeing cellulose acetate ?lm according terial such as cellulose acetate, the Water im 20 to this invention, it has been found that in order bibition of the ?lm is so low that little or no to prevent the ?lm blushing permanently, it is liquor is taken up with the result that the dyeing desirable to dye at a temperature of about 65° operation is very time consuming, to ‘70° centigrade which is lower than usual for I have found that the dyeing of ?lms possessing cellulose acetate fabric,‘ and further the ?lm low water imbibition, such as cellulose acetate should not be allowed to dry in the air at ordi ?lms, on a jig or like machine is considerably nary temperatures but should be dried immedi expedited by associating the said ?lm through ately at 80° to 110° centigrade. out its length with a fabric capable of taking up In the accompanying drawing the dye liquor. The ?lm is preferably associated Figure 1 shows the assembly of the ?lms with with two fabrics. one on each side of the ?lm. 30 two fabrics, one on each side, Generally speaking, ?lms of thermoplastic ma Figure 2 is a section on the line II—]I of ‘Fig terial possess a low water imbibition. ure 1, and According to a preferred embodiment of the Figure 3 is a diagrammatic end view of a jig invention, a ?lm of cellulose acetate is placed dyeing machine suitable for use in carrying out between two lengths of a fabric, for example of 35 the process of the invention. cotton, and the whole is then woundlon to one The ?lm l to be dyed is covered on both sides of the rollers ?xed above the dyebath. The ?lm with the fabrics 2,1 2. The assembled ?lm and and the fabrics are passed through the dyebath fabrics are then wound on the roller 3 to form and wound up on the second roller and the pas- ’ the roll 4 comprising contacting layers of ?lm I sage from one roller to the other is repeated as 40 and fabric 2. To dye the ?lm, the assembly 5 desired in the usual manner of jig dyeing. The of ?lm and fabric is led from the roller 3 into cotton fabrics serve to take up dye liquor so that dyeing of the ?lm takes place while it is wound up on the rollers, the dyeing operation being thereby considerably expedited. Although the process of this invention is par ticularly advantageous in the dyeing of ?lms of cellulose acetate, it may also be applied to the vdyeing of ?lms of other organic derivatives of cellulose such as for example, cellulose propio nate, cellulose butyrate, cellulose acetate-butyr ate, cellulose acetate-propionate, ethyl cellulose contact with the roller 6, under the guide roller 1 immersed in the dye liquor 8 in the bath 9, into 45 contact with the roller Ill and Wound up on the roller ll. When the assembly 5 has passed com_ pletely through the bath 9 and is wound up on the roller II, it is passed through the bath in the opposite direction and is rewound on roller 3, the assembly being run backwards and for wards from roller 3 to roller II and back again until dyeing has proceeded to the desired extent. This invention is illustrated by the following examples, the parts and percentages being by merised Vinyl acetate, polyvinyl chloracetate and 65 weight. acetate, ethyl cellulose and benzyl cellulose, or of other thermoplastic materials such as poly 2,413,559 3 4 Example 1 cal Industries Limited), 0.83 per cent of Duranol Red X 3B 300 (Imperial Chemical Industries Limited), 0.2 per cent of Turkey red oil and 1 per cent sodium hexametaphosphate. The ?lm is immediately dried at 100° centigrade and is found to be dyed to an amber shade. In general the above-mentioned liquor to ?lm A ?lm 0.01 inch thick and 24 inches wide pre pared from a composition containing 100 parts of cellulose acetate (57 per cent acetyl content calculated as acetic acid) 20 parts vof dimethyl phthalate and v9 parts of triphenyl phosphate is placed between two lengths of cotton fabric and '' ratio of 3:1 will be su?icient for dyeing purposes but in cases where the cotton fabric is of such The whole is then jig-dyed in the 10 a nature as to absorb all the dye liquor in the wound onto a roller, such as the roller 3 shown in the drawing. manner described, at 65° centigrade with the usual ratio of weight of liquor to weight of ?lm of 3:1 in a dyebath consisting of an aqueous dis persion containing 2 per cent of Duranol Violet 2 R 300, 0.2 per cent of Turkey red oil as dispers ing agent, and 1 per cent of sodium hexameta phosphate. After dyeing, the ?lm is immediately dye-bath, it will be necessary to use a greater proportion of dye liquor in order to maintain a surplus supply thereof in the dyebath. What I claim is: 1. A process of dyeing a ?lm possessing low Water imbibition comprising covering a side of the ?lm with afabric so that the fabric and ?lm are in face to face contact throughout the length dried at 100° centigrade and will be found to pos sess a much deeper shade than a similar cellu of the ?lm, and then dyeing the ?lm by passing lose acetate ?lm treated under identical condi the ?lm and fabric through a bath of a selected 20 tions, but with the omission of the two sheets of dye color, and winding the ?lm and fabric into cotton fabric. a roll comprising contacting layers of ?lm and Example 2 fabric, whereby the fabric acts as a reservoir of ' absorbed dye liquor for the ?lm and the ?lm A length of cellulose acetate ?lm of the same composition and dimensions as in Example 1 is 25 absorbs the dye from the dye liquor by virtue of its greater af?nity for the dye. placed between two lengths of a cotton fabric 2. A process as claimed in claim 1 wherein the and then wound onto a roller and dyed on a jig ?lm is associated with two fabrics, one on each dyeing machine in the manner described, for side. one hour at 65° centigrade with the same liquor 3. A process as claimed in claim 1 wherein the to ?lm ratio of 3:1 in a dyebath consisting of 30 ?lm is cellulose acetate. an aqueous dispersion containing 1.66 per cent RAYMOND CRAWFORD GREENLEES. of Dispersol Fast Yellow A 300 (Imperial Chemi Certi?cate of Correction December 31, 1946. Patent No. 2,413,559. RAYMOND CRAWFORD GREENLEES It is hereby certi?ed that error appears in the printed speci?cation of the above numbered patent requiring correction as follows: Column 4, line 21, claim 1, for the word “color” read liquor; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent O?ice. Signed and sealed this 4th day of March, A. D. 1947. [um] LESLIE FRAZER, First Assistant Commissioner of Patents.