Bleaching and dyeing; fluid treatment and chemical modification – Organic additive for dye composition – dye composition... – Carboxamides or thiocarboxamides
Reexamination Certificate
1998-01-13
2001-04-24
Gupta, Yogendra (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Organic additive for dye composition, dye composition...
Carboxamides or thiocarboxamides
C008S426000, C008S524000, C008S526000, C008S527000, C008S528000, C008S585000, C008S588000, C008S607000, C008S611000, C008S613000, C008S618000, C008S633000, C008S634000, C008S644000, C008S654000, C008S655000, C008S650000, C008S657000, C008S919000, C008S594000
Reexamination Certificate
active
06221113
ABSTRACT:
The present invention relates to a stable, liquid dyestuff composition comprising a basic or cationic dyestuff in salt form, an inorganic or organic acid, a phenolic derivative, water and optionally a water-miscible solvent, to a process of dyeing a substrate with said composition, to a powder or granulate form of said composition and to the use of said composition or powder or granulate form thereof in a dyeing process.
The object of the present invention is to provide stable, liquid concentrated dyestuff compositions. Generally, in dyeing processes it is more suitable to use a liquid concentrated dyestuff composition of a particular dyestuff, rather than the powder form of the dyestuff, since use of the former obviates the need for a processing step in which the dyestuff is dissolved in a solvent. Use of liquid compositions is particularly valuable in continuous dyeing processes.
It is known to prepare liquid dyestuff compositions by dissolving a cationic or basic dyestuff in a suitable solvent such as an inorganic or organic acid. Such acids include for example hydrochloric, sulfuric, phosphoric, formic, acetic, glycolic, citric, gluconic, lactic and methanesulfonic acids. Furthermore, for example any one of the following components: formamide; dimethylformamide; benzylalcohol; urea; &egr; caprolactam; glycol or ethers thereof; dextrin; or addition products of boric acid with sorbit may be added to the dyestuff solution, optionally in the presence of an additive such as a stabilizer. Such preparations may be prepared for example, as described in U.S. Pat. No. 4,149,851.
The maximum dyestuff concentration achievable in stable, liquid dyestuff compositions is influenced on the one hand by the solubility of the dyestuff and on the other by the viscosity of the composition, the latter increasing with increasing dyestuff concentration. Generally, the dyestuff concentration can be increased by increasing the proportion of organic or inorganic acid or additional solvent means. However, the use of higher proportions of acids and/or additional solvent means, suffers, for example, from the disadvantages of the associated increase in Chemical Oxidation Demand (COD) and/or increased corrosiveness of the compositions. Accordingly from both ecological and economical aspects, it is desirable to produce concentrated liquid dyestuff compositions of water and dyestuff, with low viscosity but keeping the concentration of additional components as low as possible.
It has now surprisingly been found that solutions of dyestuffs suitable for use in the present invention, when containing a phenolic derivative, display a number of advantages in dyeing processes over the previously known aqueous compositions of the same dyestuffs which do not contain a phenolic derivative.
Surprisingly, the compositions of the present invention display inter alia lower viscosities compared to compositions which differ only in that the phenolic derivative is absent. Hereinafter, the latter compositions will be referred to as analogous non-phenol-containing compositions. Furthermore, on comparing analogous non-phenol-containing compositions with compositions of the present invention (both compositions having the same viscosity) one observes that the compositions of the present invention have a higher dyestuff concentration than the analogous non-phenol-containing compositions, in all cases where the solubility limit of the dyestuff has not been reached. In other words, for a composition having a given dyestuff concentration, the viscosity of the composition of the present invention is always lower than that of the analogous non-phenol-containing composition. Thus, the compositions of the present invention require a lower concentration of acid than the analogous non-phenol-containing composition, in order to achieve a particular viscosity. Moreover, the compositions according to the present invention have a high storage stability (over 12 months). In some cases the compositions are stable for 1-2 years. By the term storage stable is meant that the compositions do not separate or form precipitates, but remain a solution, when stored.
Compositions of dyestuffs containing phenolic derivatives are known, for example, from U.S. Pat. No. 4,842,646. This patent discloses compositions of water insoluble dyes with hydrocarboxylic acids, thereby obtaining a water soluble system that can be conveniently used to directly dye cellulosic materials. It is stated therein, that by “water insoluble” is meant “. . . a dye that by itself or in the presence of a mordant [because it has been pretreated with a mordant (e.g. tannic acid or gallic acid) or because the solution in which it is to be dissolved contains a mordant (e.g. tannic acid or gallic acid)] is insoluble or is soluble to an extent of no more than 1 mg/liter of water, but can be solubilized with the aid of a hydroxycarboxylic acid so that it is soluble in an aqueous solution to an extent of at least about 150 mg of dye per milliliter of solution.”
The dyestuffs suitable for use in the present invention have a solubility in water either in the presence or absence of a phenolic derivative of greater than or equal to 1 g/liter of water, when the solubility is measured at 25° C. Most basic and cationic dyestuffs exhibit this degree of solubility. The basic and cationic dyestuffs suitable for use in the present invention are preferably direct dyestuffs and more preferably phthalocyanine direct dyestuffs.
In general, when comparing dyestuff compositions of similar viscosities and concentrations, the compositions of the present invention have a lower level of free acid (acid which is not used for salt formation) and/or additional water-miscible solvent (as hereinafter defined) compared to known compositions of the same dyestuffs suitable for use in dyeing processes. Thus by adding a phenolic derivative and at least one organic or inorganic acid to an aqueous solution of a basic and/or cationic water soluble dyestuff of the invention, and optionally a water-miscible solvent, one obtains a storage stable liquid composition which is particularly suitable for use in dyeing processes for the reasons discussed above.
The composition of the present invention also demonstrates very good exhaust, even after periods of storage. A comparison between the concentration of dyestuff remaining in the waste-water (water remaining after dyeing) resulting from e.g. a conventional paper dyeing process or from exhaust dyeing using a composition of the invention which has been stored for 12 months at 20° C. and the same composition which has not been stored, shows that the compositions which have been stored exhibit the same level of exhaust as those which have not been stored. Accordingly, storage does not adversely affect the dyeing strength of the compositions of the invention.
The present invention provides a liquid dyestuff composition comprising from 4 to 50 wt % of a basic or cationic water soluble dyestuff, from 1 to 20 wt % of an organic or inorganic acid and 0.1 to 15.0 wt % of a phenolic derivative, the dyestuff having a solubility in water in the presence or absence of a phenolic derivative of at least 1 g/liter at a temperature of 25° C. and the composition being made up to 100 wt % by water and optionally a water-miscible solvent and/or dissolving auxiliary.
The compositions of the present invention are suitable for use in a process of dyeing a hydroxy group- or nitrogen-containing organic substrate. Particularly suitable substrates are leather, textile materials comprising cellulose, especially cotton, bast fibers and paper. A preferred substrate is paper.
The compositions may be applied to the substrate to be dyed, using any conventional dyeing process, for example the textile dyeing processes such as exhaust or pad-dyeing or a paper dyeing process such as continuous dyeing in the stock.
Accordingly, the present invention further provides a process of dyeing a substrate comprising applying to said substrate a composition of the present invention by means of an exhaust- or pad-dy
Clariant Finance (BVI) Limited
Gupta Yogendra
Hanf Scott E.
Mruk Brian
LandOfFree
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