Monoazo dyes which are stable under dyeing conditions, their pre

Details Monoazo dyes which are stable under dyeing conditions, their pre Monoazo dyes which are stable under dyeing conditions, their pre

1997-09-05

1999-06-29

Einsmann, Margaret

Bleaching and dyeing; fluid treatment and chemical modification

Dry dye composition other than mere mixture of two or more...

Dye in specified form other than mere powder

8662, 534575, C09B 6748, C09B 6710, C09B 6738, C09B 4100

Patent

active

059171219

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to new crystal modifications of the dye of the formula (I) ##STR2## which are stable during dyeing and to a process for their preparation.
The dye of the formula (I) is known per se. It can be obtained in the manner described in DE-A -15 44 451 by diazotising 2-chloro-4-nitroaniline and coupling the resulting diazonium salt onto N-(2-cyanoethyl)-N-(2-phenylethyl)aniline in an aqueous mineral acid medium. In this reaction it is however obtained in an unstable crystal modification (the ".alpha.-modification"), whose X-ray diffraction diagram (Cu K.sub..alpha. radiation) is shown in FIG. 2 and which is characters by lines at the following diffraction angles 2 .theta. (.degree.):
The dye of the formula (I) is also obtained in this modification, which is unstable during dyeing, if the coupling is carried out in the presence of a specific carboxylic acid ester, such as for example butyl acetate, according to the
The use of such aliphatic carboxylic acid esters, in particular butyl acetate, also has the disadvantage that the coatings and in particular the rubber linings of the reaction vessels, undergo attack and these vessels are thus permanently damaged. The required dye is contaminated as a result.
Powder and liquid preparations produced from the dye in its unstable crystal modification display considerable technical deficiencies, particularly during the handling thereof, and also even during their production as well as during the dyeing of textile polyester materials. Technical deficiencies during the handling of such preparations occur for example when they are redispersed, i.e. when they are incorporated in dyeing liquors and printing pastes. Problems such as sedimentation, agglomeration, phase separation and the formation of putty-like deposits do however occur particularly when these preparations are used in a redispersed form in modern dyehouses.
The object of the present invention was to provide dye modifications which are stable during dyeing as well as an economical process for their preparation.
New crystal modifications (the ".gamma. modification and the .beta. modification") of the dye of the formula (I) ##STR3## which are stable during dyeing, have been found, which have lines in the X-ray diffraction diagram (Cu K.sub..alpha. radiation) at the following diffraction angles 2 .theta. (.degree.):
The X-ray diffraction diagram, which was recorded with Cu K.sub..alpha. radiation, of the .gamma. modification, which is stable during dyeing, is shown in FIG. 1 and that of the .beta. modification in FIG. 3. These diagrams were recorded using a computer-controlled Siemens D 500 powder diffractometer.
The dye can be used without problems if it is present in the .beta. or .gamma. modification according to the invention. These .beta. and .gamma. modifications allow higher space-time yields to be obtained in the production of powder or granular preparations, and dyeings are produced on piece goods and wound packages which are speck-free and free of dye deposits, i.e. are homogeneous.
The .beta. modification according to the invention can be obtained by heating the dye which is present in the .alpha.modification in an aqueous phase to temperatures of preferably 70 to 150.degree. C., and particular 90 to 130.degree. C. This heating process is usually carried out in an aqueous suspension and appropriately with stirring. If the temperatures used are higher than the boiling point of the aqueous phase, the conversion into the .beta. modification is carried out in closed vessels, such as for example autoclaves. Heating is carried out until the a modification is completely converted into the .beta. modification.
The complete conversion of the a modification into the .beta. modification usually takes 0.5 to 5 hours, it being possible to monitor the reaction by conducting X-ray or microscopic examinations of samples extracted during the heat treatment.
During the conversion of the .alpha. modification into the .beta. modification it is possible to add one or more surface-active substances t

REFERENCES:
patent: 4319880 (1982-03-01), Opitz et al.
patent: 4327999 (1982-05-01), Koller et al.
patent: 4795807 (1989-01-01), Buhler
patent: 5069682 (1991-12-01), Binder et al.
Neumuller, Rompps Chemie-Lexikon (1983) pp. 1714-1715.

Affiliated with

Also associated with

Rating

Monoazo dyes which are stable under dyeing conditions, their pre does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Monoazo dyes which are stable under dyeing conditions, their pre, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Monoazo dyes which are stable under dyeing conditions, their pre will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1377006