US2992877A - Dyeing process - Google Patents

Description

Patented July 18, 1961 2,992,877 DYEING PROCESS Walter Hees, Koln-Hohenberg, and Otto Schneider, Koln- Flittard, Germany, assignors to Farhenfabrilren Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Aug. 13, 1957, Ser. No. 677,845 Claims priority, application Germany Aug. 30, 1956 4 Claims. (Cl. 855) The present invention relates to the dyeing of articles from polyesters or cellulose triacetate with disperse dyestuffs; more particularly it concerns a process for the dyeing of these articles with disperse dyestuffs which consists in carrying out the dyeing in the presence of an ester of alkyl groups-containing salicylic acids.

As esters of alkyl groups-containing salicylic acids are particularly suitable the esters of low molecular weight aliphatic alcohols with salicylic acids substituted by low molecular weight alkyl groups, such as the methyl esters of: ortho-, metaor para-cresotic acid.

These esters which are water-insoluble, are preferably used in the dyebath in the form of an emulsion, prepared with anion-active or non-ionic emulsifiers.

The requisite amounts of the esters may easily be as certained in each case by preliminary tests; in general, amounts of 2-6 grams per litre of dyebath, in accordance with the desired depth of the dyeing, will be sufficient.

As disperse dyestufis there may be used the dyestuffs known under this designation; cf. for example Diserens, Die neuesten Fortschritte in der Anwendung der Farbstofie, Basel 1949, volume 2, p. 254 seq.

The process according to the invention allows of dyeing articles, i.e. threads, fibres, fabrics and foils, from polyesters of the polyethylene terephthalate type as well as from cellulose triacetate in deeper shades with disperse dyestufis than can be attained in the presence of the esters of salicylic acids already proposed and which are unsubstituted or substituted by chlorine, nitro-, hydroxyor amino-groups.

The following examples serve to illustrate the invention without, however, limiting the scope thereof.

Example 1 Polyester fibres from polyethylene terephthalate are introduced into a bath having a liquor-to-goods ratio of 40:1 which contains per litre 0.75 gram of the disperse dyestufl? 1-amino-4-hydroxy-2-bromoanthraquinone and grams of a mixture of 83 parts by weight of the methyl-ester of o-cresotic acid and 17 parts by weight of an emulsifier mixture of equal parts of an aralkyl sulphonate and a non-ionic polyglycol ether. The goods are then dyed in usual manner at -98 C. for 2 hours. A deep red dyeing is thus obtained having excellent fastness to light.

Example 2 Polyester fibres from polyethylene terephthalate are introduced into a bath having a liquor-to-goods ratio of 40:1 which contains per litre 0.75 gram of the disperse dyestufi l-hydroxy-4-(p-tolyl)amino-anthraquinone and 5 grams of a mixture of 83 parts by weight of a mixture of methyl esters of ortho-, metaor para-cresotic acid and 17 parts by weight of the emulsifier mixture indicated in Example 1. The dyeing effected in usual manner at 96-98 C. for 2 hours yields a deep blue shade exhibiting excellent fastness to light.

We claim:

1. A process for the dyeing of articles from a member of the group consisting of polyesters and cellulose triacetate with disperse dyestuffs which comprises carrying out the dyeing in the presence of an ester of a low molecular weight aliphatic alcohol with a salicylic acid substituted in the benzene ring by a low molecular weight alkyl group.

2. A process according to claim 1 wherein the dyeing is carried out in the presence of the methyl ester of a cresotic acid.

3. A process according to claim 1 wherein the dyeing is carried out in the presence of a mixture of methyl esters of ortho-, meta-, and para-cresotic acid.

4. A process according to claim 1 wherein the dyeing is carried out in the presence of the methyl ester of orthocresotic acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,881,045 Mecco Apr. 7, 1959 FOREIGN PATENTS 579,896 France Oct. 25, 1924 OTHER REFERENCES Du Pont: The Technical Bulletin, vol. 8, No. 2, pp. 69-78, June 1952.

Zimmerman: Amer. Dyestufi Rep., pp. 296-302, April 25, 1955.

Fern: Journ. Soc. Dyers and Colourists, vol. 71, pp. 840-856, December 1955.

Claims (1)

1. A PROCESS FOR THE DYEING OF ARTICLES FROM A MEMBER OF THE GROUP CONSISTING OF POLYESTERS AND CELLULOSE TRIACETATE WITH DISPERSE DYESTUFFS WHICH COMPRISES CARRYING OUT THE DYEING IN THE PRESENCE OF AN ESTER OF A LOW MOLECULAR WEIGHT ALIPHATIC ALCOHOL WITH A SALICYLIC ACID SUBSTITUTED IN THE BENZENE RING BY A LOW MOLECULAR WEIGHT ALKYL GROUP.