GB2079327A

GB2079327A - Liquid formulations of copper-containing dyes>

Info

Publication number: GB2079327A
Application number: GB8024915A
Authority: GB
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1980-07-04
Filing date: 1980-07-30
Publication date: 1982-01-20
Also published as: EP0044805A3; EP0044805A2

Description

Liquid formulations of copper-containing dyes The invention relates to novel liquid formulations of copper-containing dyes, a process for their preparation and their use for dyeing and printing cellulose materials and in particular paper. The use of water-soluble dyes in the form of concentrated aqueous solutions, which in industry are frequently termed "liquid dyes", has achieved industrial significance in recent years for dyeing paper and textiles. The main advantages of such "liquid dyes" over pulverulent dyes are the avoidance of dusting during handling and the ease and speed with which the "liquid dyes" can be measured. In the ideal case, a "liquid dye" consists of an aqueous solution of the dye, avoiding the problems of elimination or recovery which arise in the case of solutions containing organic solvents instead of water. Frequently, however, the solubility of the dye in water is not sufficient to give aqueous solutions of the concentration which is desired for use as "liquid dyes", i.e. at least 15% by weight. German Offenlegungsschrift 1,794,250 describes, for example, liquid formulations which contain, inter alia, copper-containing disazo dyes dissolved in a mixture of monopropanolamine or an aminothiol and water. The liquid formulations described in this Offenlegungsschrift contain the dye in the form of inorganic salts, for example alkali metal salts and in particular sodium salts, in amounts of only about 11 to about 12% by weight, based on the total preparation. For example, with the copper-containing disazo dye of the formula

it is not possible to prepare a sufficiently concentrated, storage-stable solution of this dye if the latter is dissolved in water in the form of an alkali metal salt, for example in the form of the lithium, potassium or sodium salt which is obtained when the dye is prepared by conventional processes. Even when the procedure of the above German Offenlegungsschrift 1,794,250 is followed, it is not possible to obtain a liquid formulation which is concentrated in respect of dye. A solution containing at most about 5 or 6 per cent by weight of dye is obtained. The object of the invention was to prepare a storage-stable, concentrated liquid formulation for the said copper-containing disazo dye. This object has been achieved by using the said dye in the form of an alkylamine salt or alkanolamine salt dissolved in water. The formulations according to the invention are thus stable, concentrated liquid formulations of copper-containing dyes, which formulations are miscible with water in all proportions and contain at least one copper-containing dye, which in the form of the free acid has the formula

in which X is the azoxy or azo group or preferably a direct C-C bond, dissolved in water and an alkylamine or alkanolamine in the amount required to adjust the pH value of the liquid formulation to 6.5 to 8.5, the dye being in the form of the alkylamine salt or alkanolamine salt. The sulfonic acid groups are, in particular, in the 5,7-, 6,8- and in particular 3,6-positions. In a preferred embodiment, a dye of the formula

is used, in which X is as defined underformula (I). The copper-containing dyes according to the invention are known and can be prepared by known processes. Preferably, the liquid formulations according to the invention contain the dye in amounts of 15 to 30 and in particular of 15 to 25 per cent by weight, the dye being calculated as the free acid. These formulations also contain 60 to 85 and in particular 70 to 80 per cent by weight of water, based on the total formulation. They also contain an alkylamine or alkanolamine in an amount such that the pH value of the formulation is about 6.5 to 8.5 and preferably 7 to 8, the dye being in the form of the alkylamine salt or alkanolamine salt. The formulations can, if desired, also contain further additives in small amounts.Alkylamines suitable for adjusting the pH to the desired value are, for example, alkylamines having 1 to 6 carbon atoms, such as methylamine and ethylamine; suitable alkanolamines are, for example, those having 1 to 4 carbon atoms per alkanol moiety; alkanolamines in this context are ethanolamine, diethanolamine, n-propanolamine and i-propanolamine, as well as triethanolamine, di-isopropanolamine and tri-isopropanolamine. Alkylamines having 1 to 6 carbon atoms and in particular ethylamine are preferred, and preferred alkanolamines are in particulartriethanolamine and especially di- and tri-isopropanolamine. Preferably, the liquid formulation according to invention contains about 2 to 10 per cent by weight and in particular 5 to 8 per cent by weight of the alkylamine or alkanolamine. Further additives which these liquid formulations can contain are extenders, such as an electrolyte (for example NaCI or Na2S04): solubility improvers, such as urea or pentaerythritol; dispersants; bacteriostatic agents; anti-foams and the like. They can contain up to about 3 per cent by weight, but preferably not i more than 1.5 per cent by weight, of the further additives. These novel liquid formulations are true solutions. They are concentrated in respect of dye, have a viscosity of about 20 to 50 cP/20[deg]C, are stable on storage over a period of several months, even at temperatures between about -10[deg]C and +60[deg]C, and are miscible with cold and warm water in all proportions. The liquid formulations according to the invention can be prepared direct from the dye press cake which contains the dye in the form of the free acid and the preparation is effected, for example, by adding the copper-containing dye according to the definition, in the form of the free acid, either as the dried product or preferably in the form of the aqueous press cake, to water at room temperature and immediately thereafter adding the alkylamine or alkanolamine in an amount such that the pH value of the resulting solution is about 6.5 to 8.5 and preferably 7 to 8. If an aqueous press cake is employed, it may not be essential, depending on the water content of the press cake, to add water separately. The liquid formulations according to the invention are used, after diluting with water if necessary, in particular for dyeing and printing paper, including semi-cardboards and cardboards, and these materials can be dyed, for example, by beater dyeing, by coating or by dip dyeing. Moreover, liquid formulations of the said type can also be used for a continuous or discontinuous dyeing process fortextile materials, especially cellulose and polyamide. The following examples illustrate the invention. "SR" signifies "Schopper Riegler" and "abs." signifies "absolutely dry"; percentages are by weight unless indicated otherwise.

Example 1: 600 g of an aqueous press cake containing about 20g of electrolyte (NaCI, Na2S04), 425 g of water and 155 g of the dye of the formula

in the form of the free acid are dispersed in 300 g of water. Immediately thereafter, the pH of the viscous paste is adjusted to 7 to 8 with about 70 g of triisopropanolamine, whereupon a solution results which is stirred for about a further 2 hours at room temperature. Finally, the solution is filtered through a steel sieve in order to remove any impurities which may be present. A true dye solution is obtained which has a viscosity of about 40 cP at 20[deg]C and consists of 23% of the abovementioned dye in the form of the triisopropanolamine salt (consisting of about 16% of free dye acid and 7% oftriisopropanolamine), 75% of water and 2% of electrolyte (NaCI, Na2S04).This dye solution is stable for several months at temperatures of-10[deg]C to +40[deg]C and is miscible with water in all proportions. After diluting with water, it is suitable for dyeing paper. In orderto further increase the storage stability, the dye press cake can be prewashed with a 1% hydrochloric acid solution in order to reduce the amount of electrolyte. (Examples 2 to 4): The procedure of the above Example 1 is repeated, except that the components indicated in Examples 2 to 4 below are used. Dye solutions are obtained which have the composition indicated in these examples and have similar properties.

Example 2: Amounts of the components employed: 600 g of the aqueous press cake indicated in Example 1, 25 g of ethylamine and 375 g of water. Composition of the concentrated dye solution: 15.5 per cent by weight of dye (calculated as the free acid), 2.5 per cent by weight of ethylamine, 2 per cent by weight of electrolyte and about 80 per cent by weight of water.

Example 3: Amounts of the components employed: 600 g of the aqueous press cake indicated in Example 1, 60 g oftriethanolamine and 340 g of water. Composition of the concentrated dye solution: 15.5 per cent by weight of dye (calculated as the free acid), 6 per cent by weight of triethanolamine, 2 per cent by weight of electrolyte and 76.5 per cent by weight of water.

Example 4: Amounts of the components employed: 600 g of the press cake indicated in Example 1, 40 g of diisopropanolamine and 360 g of water. Composition of the concentrated dye solution: about 16 per cent by weight of dye (calculated as the free acid), 4 per cent by weight of diisopropanolamine, 2 per cent by weight of electrolyte and about 78 per cent by weight of water. If the diisopropanolamine is replaced by 20 g of n-propanolamine or isopropanolamine, similarly stable, concentrated solutions of the dye are obtained. Example 5: Printing paper 800 kg of bleached sulfate cellulose and 200 kg of bleached sulfite cellulose are introduced, in the form in which they are supplied, into a pulper, in which 14 m of factory water have been placed, and the mixture is pulped until speck-free. The pulping operation takes 30 minutes. The pulped cellulose is then transferred to a discharge vat. From the discharge vat, the cellulose suspension is beaten in a refinerto a beating degree of 25[deg] SR and then passes into a mixing chest. Further additives of 250 kg of kaolin la (as a filler) and 0.1 to 0.05% of the dye formulation according to Example 1, based on abs. fibre, are added in the mixing chest. After an absorption time of 15 minutes, 2% of resin size, based on abs. cellulose are added, and after 10 minutes 4% of alum, based on abs. cellulose, are added.This paper pulp passes via the conventional processing procedures to the paper-making machine. A blue-colored printing paper is obtained. Example 6: Tissue paper 1,000 kg of bleached sulfate cellulose are introduced, in the form of which it is supplied, into a pulper, in which 14 m of factory water have been placed, and pulped until speck-free. The pulping operation takes 30 minutes. The pulped stuff is then transfer red to a discharge vat. From the discharge vat, the cellulose is beaten in a refinerto a beating degree of 25.SR and then passes into a mixing chest. 0.1 to 0.05% of the dye formulation according to Example 1, based on abs. fibre, is added in the mixing chest. After an absorption time of 15 minutes, this paper pulp passes via the conventional processing procedures to the paper-making machine. A blue-coloured tissue paper is obtained. Example 7: Size press application 5 kg of dye in the form of an aqueous formulation according to Example 1 are dissolved in 1,000 1 of a 10% aqueous, anionic starch solution (soluble starch which has been digested by oxidation) and the solution is applied to a paper web by means of a size press. The amount of the above solution applied is 1.5 g/m abs. per side. A blue-coloured paper is obtained.

Claims

1. A stable, concentrated liquid formulation of a copper-containing dye, which formulation is miscible with water in all proportions and contains not ess than 15 per cent by weight of a dye, which in the form of the free acid has the formula

in which X is the azoxy or azo group or a direct C-C bond, dissolved in water and an alkylamine or alkanolamine in the amount required to adjust the pH value of the liquid formulation to 6.5 to 8.5, the dye being in the form of the alkylamine or alkanolamine salt.

2. A liquid formulation according to claim 1, wherein X is a direct C-C bond.

3. A liquid formulation according to Claim 1 or 2, which consists of 15 to 30 per cent by weight of the dye, calculated as the free acid, dissolved in 60 to 85 per cent by weight of water and an alkylamine or alkanolamine in the amount required to adjust the pH value of the solution to 6.5 to 8.5, and also, if desired, further additives.

4. A liquid formulation according to Claim 3, which consists of 15 to 25 per cent by weight of the dye, calculated as the free acid dissolved in 70 - 80 per cent by weight of water.

5. A liquid formulation according to any of Claims 1 to 4, which contains, as the alkylamine, an alkylamine having 1 to 6 carbon atoms.

6. A liquid formulation according to any of Claims 1 to 4, which contains, as the alkanolamine, an alkanolamine having 1 to 4 carbon atoms per alkanol moiety.

7. A liquid formulation according to Claim 6, which contains triethanolamine, diisopropanolamine or triisopropanolamine.

8. A liquid formulation according to Claim 7, which contains the copper-containing dye in the form ofthe triisopropanolamine salt.

9. A liquid formulation according to any of Claims 1 to 8, which contains, as the dye, a dye of the formula I in which the sulfonic acid groups are in the 5,7-, 6,8- or 3,6-positions.

10. A liquid formulation according to Claim 9, which contains, as the dye, a dye of the formula (1) in which the sulphonic acid groups are in the 3,6positions.

11. A liquid formulation according to any of Claims 1 to 10, which contains, as the dye, a dye of the formula

in which X is defined in claim 1.

12. A liquid formulation according to Claim 11, which contains, as the dye, the dye of the formula

13. A liquid formulation according to any of Claims 1 to 12, which contains, as further additives, electrolyte, bacteriostatic agents and/or anti-foams.

14. A liquid formulation according to Claim 1, substantially as herein described.

15. A process forthe preparation of a liquid formulation according to Claims 1 to 14, which comprises adding at least one dye of the formula I indicated in Claim 1, as the free acid, in the form of the aqueous press cake, to water at room temperature, and immediately thereafter adding an alkylamine or alkanolamine in an amount such that the pH value of the resulting solution is about 6.5 to 8.5.

16. A process according to Claim 15, substantially as herein described.

17. A liquid formulation containing a coppercontaining dye as defined in Claim 1, when prepared by a process according to Claim 15 or 16.

18. A process for the dyeing orprinting of cell ulose, polyamide or paper in which there is used as dyestuff vehicle or printing ink a liquid formulation according to any of Claims 1 to 14 or 17.

19. Process according to Claim 18,forthe dyeing of paper, semi-cardboard or cardboard in which the liquid formulation is incorporated in the pulp from which the paper, semi-cardboard or cardboard is subsequently made.

20. Process according to Claim 18, for the dyeing or printing of paper, semi-cardboard or cardboard in which the liquid formulation is applied to the paper, semi-cardboard or cardboard after it has been manufactured, by coating or by dip dyeing.

21. Process for the dyeing or printing of cellulose, polyamide or paper substantially as herein described.

22. Cellulose, polyamide or paper when dyed or