Dye composition, their production and their use

Details Dye composition, their production and their use Dye composition, their production and their use

2002-05-17

2004-09-28

Einsmann, Margaret (Department: 1751)

Bleaching and dyeing; fluid treatment and chemical modification

Organic additive for dye composition, dye composition...

Alcohol

C008S506000, C008S522000, C008S527000, C008S543000, C008S673000, C008S680000

Reexamination Certificate

active

06797016

ABSTRACT:

For the use of water-soluble anionic dyes, liquid formulations are preferred in industry. Since it is generally not always possible, even in the case of very readily soluble anionic dyes, to prepare highly concentrated aqueous solutions which contain the dye, even at high concentration, in fully dissolved form and/or are sufficiently stable, in particular are sufficiently storage and transport stable and also stable during application, for example during spraying, organic solvents and optionally solubilizers have been employed to produce corresponding aqueous/organic concentrated dye solutions. Aqueous/organic dye solutions of this type are particularly welcome if the solutions are applied directly, for example for spraying, spray dyeing or for other similar application methods.
It is known, for example from GB-A-1545529, EP-A-508443 and JP-A-07-118585, to prepare solutions of this type in which, as organic components of the aqueous/organic solution, use is made of solvents and/or solubilizers which belong to the category of alcohols or pyrrolidones or hydrotropes.
GB-A-1545259 uses a mixture of N-methylpyrrolidone, benzyl alcohol and urea for the preparation of an aqueous/organic solution of certain disazo dye in which the total of the amounts of urea and N-methylpyrrolidone preponderates over the amount of benzyl alcohol employed, and where the dye can be employed as the pure product or as a water-moist press cake, but it is also noted therein (page 1, lines 40-41) that a salt content, for example as by-product from the dye production, imparts an unstable character on the liquid composition, and so it is recommended therein to desalinate the dye press cake in advance with hydrochloric acid (in Example 1 up to 1% of salt in the acidic press cake).
EP-A-508443 describes aqueous/organic solutions of certain anionic dyes in which the aqueous/organic phase amounts to from 75 to 85% by weight, where up to at most 50% thereof are water and the organic phase can consist of mono-, di- or trifunctional alcohols, and further organic solvents, such as dioxane, 2-pyrrolidone, methyl lactate, ethyl lactate and butyl lactate, may be present. It is noted therein (page 6, lines 46-47) that the stability of the compositions is impaired if the proportion of water exceeds 50% of the aqueous/organic phase.
Japanese Kokai JP-A-07118585 discloses jet printing inks which comprise similar components.
U.S. Pat. No. 4,816,244 describes certain C
4-8
-alcohols (trihydroxypentane, trihydroxyhexane and benzyl alcohol are listed) and mixtures thereof with other alcohols (glycerol, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethanol, propanol and diethylene glycol are mentioned in a general list) for the preparation of more dilute solutions of certain natural dyes, and all the examples use a trifunctional alcohol (trihydroxyhexane), mostly in a mixture with one or two further aliphatic alcohols, where an excess of alcohol or alcohol mixture compared with the dye is used in the examples, and where it is also mentioned therein (column 2, lines 15-17) that the advantageous properties of the stabilizing alcohols are effective at a dye concentration in the range from 0.01 to 10.0%.
EP-A-122224 describes a process for the production of desalinated yellow stilbene azo(xy) dye solutions by condensation of 4-nitrotoluene-2-sulphonic acid in an aqueous alkaline medium in the presence of a mixture of mono- and di- or tri-(C
2-4
-alkanol)-amines, then further addition of di- or tri-(C
2-4
-alkanol)-amine after condensation, then desalination by filtration through a membrane or treatment with an acid or with an acidic ion-exchange resin for elimination of the alkali metal ions, while the excess of the alkanolamines is not eliminated; in the specification there are mentioned some adjuvants that may be present, namely formamide, dimethylformamide, glycols, diethylene and triethylene glycols and their mono or dialkylethers, further polyethylene glycols of molecular weight 400 to 4000 or also benzyl alcohol, but particularly urea, namely in a concentration of up to 35% by weight referred to the ready dye solution. The examples describe only dye solutions containing a substantial amount (about 20 or 30%) of urea, which is also in substantial excess over the amount of dye present. Also this document, analogously to GB-A-1545529, illustrates dye compositions which need to have been desalinated and contain a high amount of an adjuvant, which in EP-A-122224 is exemplified with urea.
It is evident from the prior art outlined above that it has been attempted a number of times to prepare stable aqueous/organic solutions of certain anionic dyes, where relevant amounts or certain combinations of organic solvents and/or solubilizers are necessary and in some cases purification processes are also necessary, and thus GB-A-1545524 contains a prejudice against concentrated solutions in which the dye (for example as press cake) contains a salt, EP-A-508443 contains a prejudice against concentrated solutions in which the organic solvent content is less than 50%, and U.S. Pat. No. 4,816,244 contains a prejudice against solutions containing more than 10% of dye. To find of a stable aqueous/organic solution of water-soluble anionic dyes with a high dye content, particularly greater than 10% by weight, and a significantly lower content of organic phase was a problem that had hitherto not been solved.
Surprisingly, it has now been found that concentrated aqueous benzyl alcohol-containing solutions of water-soluble anionic dyes as defined below which are distinguished by their particularly good stability (even if they contain, for example, salt as by-product from their synthesis) and have a flow behaviour which is similar to that of a more dilute aqueous solution and which are perfectly suitable for dye application or other indirect or direct uses for dyeing or colouring of substrates can be prepared using a very small amount of benzyl alcohol, essentially without addition of further alcohols or other organic solvents or solubilizers.
The invention relates to these solutions, to their production, to their use and to the substrates treated therewith, particularly non-fibrous hydrophilic substrates.
A first subject-matter of the invention is thus a concentrated dye composition (P) which is a solution of y % by weight of at least one anionic dye (A) in a solution of x % by weight of benzyl alcohol (B) in water, and z % by weight of at least one formulation additive (F),
in which
x is a number in the range from 0.5 to 4,
y is a number in the range from 5 to 35
and
z is a number in the range from 0 to 2,
and is essentially free from alcohols other than (B) and from solvents or solubilizers other than water and (B).
As anionic dyes (A), any desired anionic dyes generally come into consideration, essentially those which are inert towards alcoholic hydroxyl groups, principally
(A
1
) acid dyes,
(A
2
) direct dyes,
(A
3
) mordant dyes
and
(A
4
) reactive dyes, optionally in hydrolysed form.
As “acid dyes”, “direct dyes”, “mordant dyes” and “reactive dyes”, dyes which are known under these terms generally come into consideration. for example those as defined and described in the “Colour Index” under the names “Acid Dyes”, “Direct Dyes”, “Mordant Dyes” and “Reactive Dyes” and in particular also as listed therein under these terms. The term hydrolysed form of a reactive dye is taken to mean one which conforms in formula terms to the structure of the respective reactive dye, with the difference that the fibre-reactive substituent (for example F, Cl, Br or a sulphato group) has been converted into OH in the presence of alkali (for example NaOH) or also contains an OH group through water adduction (for example onto a vinylsulphonyl group). Of the said dye categories, preference is given to the acid dyes (A
1
). The dyes (A), in particular (A
1
), are principally those which contain at least one sulpho group, optionally in salt form, and optionally contain further acid groups (for example carboxyl groups and/or phosphonic acid groups),

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