US1645925A - Production of fast dyeings - Google Patents

Description

' Patented a. 18, 1927.

UNITED STATES PATENT. OFFICE.

FRITZ PETERHAUSER, OF RIEHEN, NEAR BASEL, SWITZERLAND, ASSIGNOR TO'THE FIRM DURAN!) & HUGUENIN S. A., OF BASEL, SWITZERLAND.

PRODUCTIQN on FAST DYEINGS.

No Drawing. Application filed March 12, 1925, Serial No. 15,136, and in Germany March 20, 1924.

According to U. S. Letters Patent application Ser; No. 653,567, filed July 24, 1923, fast dyeings are produced on fibres or other substrata by impregnating the latter with solutions of ester salts of vat dyestufi's, such as are obtained according to the process of U. S. Letters Patent No. 1,448,251, and by develo ing afterwards the dyeing, by way of reormation of the parent vat dyestufi, with the assistance of a suitable oxidizing agent. In above mentioned Letters Patent-a plication Ser-. No. 653,567, it has been state that these ester salts have for the most part no afiinity to the materialto be dyed. With reference to the animal fibre, this statement has been modified as in the same Letters Patent application further down it has been mentioned that these ester salts fii themselves on the animal fibre from a weak acid bath and at a higher temperature.

It has now further been found that vari-- ous cellulosic fibres, especially cotton, mercerized cotton, viscose and the like acquire anpessentiall enhanced receptivity. for these estersalts w en there is added to the dyebath a salt which is capable of lessening the solubility of the ester-salt in water and thus increases the proportion of the ester-salt taken up b the fibre, so that in the subsequent deve opment in the oxidation bath, much dee' er d eings can be obtained than without t is a dition of salt, a fact which greatly enhances the dyeing. Salts which are suitable for this purpose are for example common salt, Glauber salt etc.

The im roved process may be explained by the fol owing example:

In a bath containing 6.6 gm. of the'sodium salt of the leuco indigo sulphuric acid ester, obtained according to Example I of said U. S. Letters Patent No. 1448,251, 6.6 grs. of nitrite and 33 s. of Gllauber salt, viscose is impregnate at ordinary temperature .dye bath.

been added as in the case of t e first bath.

Then rinse and dry. Thus a deep dyeing fast to rubbing is obtained, which is much deeper than the one which could have been obtained without the addition of salt to the Instead of viscose, cottonor mercerized cotton can be dyed in the same way.

The effect of this addition of salt seems to vary on the different fibres. On viscose the efiect is especially stron On weavings with different threads an the like, dyeing efi'ects of difierent intensity can also be pro duced according to .this process.

Obviousl the oxidation will be efiected in a secon bath with iron chloride, nitrite and sulphuric acid etc. as stated in the cited U. S. Letters Patent application Ser.

What I claim is:

1. A process for producing fastdyeings by means of'ester salts of vat-dyestufis resulting from their leuco-com ound polybasic acid esters, consisting in adding to the dye bath a solubilit lessening salt capable of increasing the a sorption power of the fibre for the vat dyestufi ester salts, for the pur pose of producing deeper dyeings.

2. A process for producing fast dyeings by means of ester salts of vat-dyestufis resulting from their 1eucjo-compound polybasic .80 acid esters, consisting in adding Glauber salt .to the dye bath so as to increase the absorption power'of the fibre for the vat-dyestufl' ester salts, for the purpose of producing deeper dyeings.

- In witness whereof I have hereunto signed my name this 28th da of February, 1925.

FRITZ ETERHAUSER.