GB1594657A - Process for producing liquid dye concentrates - Google Patents

Description

(54) PROCESS FOR PRODUCING LIQUID DYE CONCENTRATES (71) We, SANDOZ LTD., of 35 Lichtstrasse, 4002 Basle, Switzerland, a Swiss Body Corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a process for the production of concentrated liquid dye preparations..

According to the invention there is provided a process for the production of a concentrated liquid preparation containing 20% to 50% by weight of a dyestuff of the Azo, nitro or anthraquinone series having one or two sulpho groups, the process comprising forming a mixture of the dyestuff with water and an organic solvent which is watermiscible at room temperature, the solvent being selected from a) an organic acid amide b) a glycol ether and c) a polyglycol and at a temperature of at least 600C, separating the predominantly organic phase containing the dyestuff from the predominantly aqueous phase.

The solvent used is such that it is miscible with water at room temperature but on raising the temperature to at least 600C the solvent becomes sufficiently less miscible to allow separation of the organic phase from the aqueous phase, with the dye being predominantly more soluble in the orgnanic than the aqueous phase.

Where an organic acid amide is employed as the organic solvent, such is preferably an acid amide of the benzene series, most preferably dimethylbenzamide.

Where a glycol ether is employed as the organic solvent, such is preferably a C24 alkylene-mono- or diglycol C1-4 alkyl ether, more preferably an ethylene or propylene(di)glycolether, where the ether radical contains a propyl or butyl group, and most preferably diethylene gly colmonobutylether.

Where a polyglycol is employed as the organic solvent, such is preferably a polyethylene or polypropylene glycol with a molecular weight of up to 3,000, particularly preferred being polyethylene glycols with a molecular weight in the range of from 300 to 600 and polypropylene glycols with a molecular weight in the range of 2,000 to 3,000.

The dyestuffs are known classes of dyestuffs (Colour Index) and included are metal complex sulpho group bearing dyes of the stated series.

The temperature at which phase separation takes place is generally from 60"C up to the boiling point of the mixture. At these temperatures a predominantly organic phase and a predominantly aqueous phase form and separation of one phase from the other can be carried out in conventional manner, e.g. by decanting off the desired organic phase or by simple running off of the aqueous phase to leave the desired organic phase.

The weight ratio of organic solvent to water employed in the process, is preferably not less than 1:10 and is most preferably about 1:4.

If desired, and to facilitate the phase separation, salt may be added to the mixture.

This is particularly of advantage where the dyestuff is present in a form low in salt content. The preferred salt content of the mixture is from 50 to 200 git, more preferably from 100 to 150 g/l, the aqueous phase, after phase separation, preferably containing at least 5%, more preferably from 5 to 20% and most preferably from 10 to 15% of salt. The preferred salts employed are sodium sulphate and chloride.

The dyestuff may be in moist press-cake form or in the form of a dry dyestuff preparation. However, the process of the invention may also be carried out on aqueous reaction media in which the dyestuff is produced, that is to say by taking an aqueous reaction medium containing the dyestuff, and without the normal dyestuff isolation or salting out step, adding thereto the solvent as herein before specified and carrying out the phase separation at an elevated temperature, optionally with addition of salt. By operating in this way, the conventional filtration and drying steps are obviated.

The concentrated liquid dyestuff prepara tions produced by the process of the invention preferably contain from 30% to 40% by weight of dyestuff. It has been found that the preparations show good storage stability within a rela timely wide temperature range, i.e. from about -20 C to +50 C.

The preparation produced according to the invention can be used in manner conventional for liquid dye preparations.

The following examples, in which all parts and percentages are by weight, illustrate the invention.

Example 1: 150 Parts of dry dyestuff C.I. Acid Violet 48 (technical grade) are dissolved in 150 parts of polyethylene glycol, m.w. 300, and 600 parts of water. An almost homogeneous solution is formed.

This solution is subsequently heated to boiling point, and the salt content is adjusted to 150 g/l whereby two phases are formed. The upper dark coloured dyestuff-solvent phase and the lower almost colourless aqueous phase which contains salt, are separated at just below boiling point. The dye content in the separated organic phase is about 30% and the preparation is stable in storage.

Similar results may be obtained by using the same amount of a polypropylene glycol (m.w.

3000) dimethylbenzamide or diethylene glycol monobutyl ether instead of the polyethylene glycol (m.w. 300).

Example 2: 150 Parts of dry dyestuff C.I. Acid Orange 127 (commercial preparation) or x parts of water-moist presscake (manufactured), which corresponds to 150 parts of the dried dyestuff, are completely dissolved at about 65"C in 500 parts of polypropylene glycol, m.w. 3000, and 2000 parts of water. The temperature is kept at 650 C.

The salt content is brought to about 150 g/l by adding calcined sodium sulphate. Two phases are formed. The upper, dark coloured dyestuff-solvent phase contains almost the entire dyestuff, and the lower, almost colourless aqueous phase, which can be very easily separated at the above temperature, is practically free from dyestuff.

The organic phase is separated to give a concentrated solution (about 30% dyestuff content) which is stable in storage, and which may be further diluted with water, without precipitation occurring.

With equal amounts of dimethyl benzamide, diethylene glycolmonobutylether or polyethyleneglycol (m.w.300) similar results are obtained.

Example 3: A solution of 225 parts of dyestuff C.I. Acid Yellow 111 is produced and a further processed as described in Example 1. The highly concentrated solution obtained has about 45% dyestuff content and is stable in storage.

Example 4: A solution of 200 parts of dyestuff C.I.

Acid Red 57 may be brought into a concentrated form, as described in Example 1, the dyestuff concentration being about 40%.

Example 5: 300 Parts of dyestuff C.I. Acid Blue 127:1 (technical grade) or x parts of water-moist filter cake thereof, which corresponds to 300 parts of the dried dyestuff, are dissolved in 600 parts of polyetheylene glycol, m.w. 300, and 2400 parts of boiling water.

Calcined Glauber's salt is added to the solution until the amount of salt is about 150 g/l.

Two phases are formed. The upper, dark dyed dyestuff-solvent phase and the lower, almost colourless, aqueous phase may be very easily separated from one another at a temperature of 700C.

1000 Parts of a concentrated dyestuff solution are obtained, which contains about 300 parts of dyestuff. Similar results are obtained using polypropyleneglycol m.w. 3000, dimethylbenzamide or diethyleneglycolmonobutyl ether in place of the polyethylene glycol.

WHAT WE CLAIM IS: 1. A process for the production of a concentrated liquid preparation containing 20% to 50% by weight of a dyestuff of the azo, nitro or anthraquinone series having one or two sulpho groups, the process comprising forming a mixture of the dyestuff with water and an organic solvent which is water miscible at room temperature, the solvent being selected from a) an organic acid amide, b) a glycol ether and c) a polyglycol and at a temperature of at least 600C separating the predominantly organic phase containing the dyestuff from the predominantly aqueous phase.

2. A process as claimed in Claim 1 ,wherein the organic solvent is an organic acid amide.

3. A process as claimed in Claim 2, wherein said amide is an acid amide of the benzene series.

4. A process as claimed in Claim 3, wherein said amide is dimethylbenzamide.

5. A process as claimed in Claim 1, wherein the organic solvent is a glycol ether.

6. A process as claimed in Claim 5, wherein said ether is a C24alkylene-mono- or diglycol Cl 4alkyl ether.

7. A process as claimed in Claim 6, wherein said ether is an ethylene or propylene(di) glycolether, where the ether radical contains a propyl or butyl group.

8. A process as claimed in Claim 7, wherein said ether is diethyleneglycolmonobutyl ether.

9. A process as claimed in Claim 1, wherein the organic solvent is a polyglycol.

10. A process as claimed in Claim 9, wherein said polyglycol is a polyethylene or polypropylene glycol with a molecular weight of up to 3,000.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (20)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   tions produced by the process of the invention preferably contain from 30% to 40% by weight of dyestuff. It has been found that the preparations show good storage stability within a rela timely wide temperature range, i.e. from about -20 C to +50 C.

   The preparation produced according to the invention can be used in manner conventional for liquid dye preparations.

   The following examples, in which all parts and percentages are by weight, illustrate the invention.

   Example 1:

   150 Parts of dry dyestuff C.I. Acid Violet 48 (technical grade) are dissolved in 150 parts of polyethylene glycol, m.w. 300, and 600 parts of water. An almost homogeneous solution is formed.

   This solution is subsequently heated to boiling point, and the salt content is adjusted to 150 g/l whereby two phases are formed. The upper dark coloured dyestuff-solvent phase and the lower almost colourless aqueous phase which contains salt, are separated at just below boiling point. The dye content in the separated organic phase is about 30% and the preparation is stable in storage.

   Similar results may be obtained by using the same amount of a polypropylene glycol (m.w.

   3000) dimethylbenzamide or diethylene glycol monobutyl ether instead of the polyethylene glycol (m.w. 300).

   Example 2:

   150 Parts of dry dyestuff C.I. Acid Orange 127 (commercial preparation) or x parts of water-moist presscake (manufactured), which corresponds to 150 parts of the dried dyestuff, are completely dissolved at about 65"C in 500 parts of polypropylene glycol, m.w. 3000, and 2000 parts of water. The temperature is kept at 650 C.

   The salt content is brought to about 150 g/l by adding calcined sodium sulphate. Two phases are formed. The upper, dark coloured dyestuff-solvent phase contains almost the entire dyestuff, and the lower, almost colourless aqueous phase, which can be very easily separated at the above temperature, is practically free from dyestuff.

   The organic phase is separated to give a concentrated solution (about 30% dyestuff content) which is stable in storage, and which may be further diluted with water, without precipitation occurring.

   With equal amounts of dimethyl benzamide, diethylene glycolmonobutylether or polyethyleneglycol (m.w.300) similar results are obtained.

   Example 3: A solution of 225 parts of dyestuff C.I. Acid Yellow 111 is produced and a further processed as described in Example 1. The highly concentrated solution obtained has about 45% dyestuff content and is stable in storage.

   Example 4: A solution of 200 parts of dyestuff C.I.

   Acid Red 57 may be brought into a concentrated form, as described in Example 1, the dyestuff concentration being about 40%.

   Example 5:

   300 Parts of dyestuff C.I. Acid Blue 127:1 (technical grade) or x parts of water-moist filter cake thereof, which corresponds to 300 parts of the dried dyestuff, are dissolved in 600 parts of polyetheylene glycol, m.w. 300, and 2400 parts of boiling water.

   Calcined Glauber's salt is added to the solution until the amount of salt is about 150 g/l.

   Two phases are formed. The upper, dark dyed dyestuff-solvent phase and the lower, almost colourless, aqueous phase may be very easily separated from one another at a temperature of 700C.

   1000 Parts of a concentrated dyestuff solution are obtained, which contains about 300 parts of dyestuff. Similar results are obtained using polypropyleneglycol m.w. 3000, dimethylbenzamide or diethyleneglycolmonobutyl ether in place of the polyethylene glycol.

   WHAT WE CLAIM IS: 1. A process for the production of a concentrated liquid preparation containing 20% to 50% by weight of a dyestuff of the azo, nitro or anthraquinone series having one or two sulpho groups, the process comprising forming a mixture of the dyestuff with water and an organic solvent which is water miscible at room temperature, the solvent being selected from a) an organic acid amide, b) a glycol ether and c) a polyglycol and at a temperature of at least 600C separating the predominantly organic phase containing the dyestuff from the predominantly aqueous phase.
2. 2. A process as claimed in Claim 1 ,wherein the organic solvent is an organic acid amide.
3. 3. A process as claimed in Claim 2, wherein said amide is an acid amide of the benzene series.
4. 4. A process as claimed in Claim 3, wherein said amide is dimethylbenzamide.
5. 5. A process as claimed in Claim 1, wherein the organic solvent is a glycol ether.
6. 6. A process as claimed in Claim 5, wherein said ether is a C24alkylene-mono- or diglycol Cl 4alkyl ether.
7. 7. A process as claimed in Claim 6, wherein said ether is an ethylene or propylene(di) glycolether, where the ether radical contains a propyl or butyl group.
8. 8. A process as claimed in Claim 7, wherein said ether is diethyleneglycolmonobutyl ether.
9. 9. A process as claimed in Claim 1, wherein the organic solvent is a polyglycol.
10. 10. A process as claimed in Claim 9, wherein said polyglycol is a polyethylene or polypropylene glycol with a molecular weight of up to 3,000.
11. 11. A process as claimed in Claim 10,

    wherein said polyglycol is either a polyethylene glycol with a mol.wt. in the range of 300 to 600 or a polypropylene glycol with a mol.

    wt. in the range of 2,000 to 3,000.
12. 12. A process as claimed in any one of the preceding claims wherein the weight ratio of organic solvent to water is not less than 1:10.
13. 13. A process as claimed in Claim 12, wherein the said weight ratio is about 1:4.
14. 14. A process as claimed in any one of the preceding clairils, wherein a salt is added to the mixture.
15. 15. A process as claimed in any one of the preceding claims, wherein the mixture contains a salt in an amount of from 50 to 200 gull.
16. 16. A process as claimed in Claim 14, wherein said amount is from 100 to 150 g/l.
17. 17. A process as claimed in any one of Claims 14 to 16, wherein the salt is sodium chloride or sulphate.
18. 18. A process, substantially as hereinberfore described, with reference to any one of the foregoing Examples.
19. 19. A concentrated liquid dye preparation when obtained by a process according to any one of the preceding claims.
20. 20. A preparation as claimed in any one of the preceding claims, containing from 30 to 40% by weight of dyestuff.