Bleaching and dyeing; fluid treatment and chemical modification – Nontextile – dyeing process or product – including inorganic... – Inorganic substrate
Reexamination Certificate
2002-03-15
2004-09-28
Einsmann, Margaret (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Nontextile, dyeing process or product, including inorganic...
Inorganic substrate
C008S623000, C008S685000, C008S686000
Reexamination Certificate
active
06797014
ABSTRACT:
Structures, articles or parts made of aluminium or aluminium alloys which are provided with a protective oxide layer, in particular an oxide layer produced electrochemically by anodization, are nowadays increasingly being used in engineering and construction, for example as a component and/or for the decoration of buildings or means of transport or for utility or artistic articles. For the aesthetic design of such structures, articles or parts, they, or their oxide layers, are frequently coloured. It is therefore desirable for the coloured layers to retain their coloured design for as long as possible and consequently to have very high levels of fastness to environmentally caused influences, especially to the action of sunlight.
Usually this problem is approached by employing dyestuffs of selected structures, which provide dyeings of very high light fastnesses on anodized aluminium, such as described e.g. in EP-A-986615 or 988343.
The surface of the anodized aluminium may be sealed in various ways, e.g. with boiling water or also with particular sealants or sealing salts. In WO-A-84 00982 there is described a process for sealing the anodized, uncoloured or coloured surface in a still wet state at a temperature <30° C. with a solution containing a nickel salt and a fluoride in order to improve the touch-resistance and corrosion-resistance of the surface.
In DE-A-3641766 there is described a two-stage process for the sealing of anodized and dyed aluminium by treatment first with an aqueous Ni
2+
and F
−
ions containing solution and then with hot water or steam in order to improve the weather and light fastnesses of dyeings, the mentioned dyeing being a dyeing with a dyeing electrolyte that contains a metal salt and an organic dye component.
For the colouring of oxide layers on aluminium or aluminium alloys, dyes of various shades are known, and the oxide layers dyed therewith can be sealed in a manner which is conventional per se, for example with hot water. However, the dyeings obtainable in each case can have greatly different light fastnesses, especially after extended exposure to the sun, so that—particularly in the case of multicoloured articles—the dyeing which is the least light-fast impairs the overall impression of the coloured article. It is thus desired to achieve dyeings with better light fastness properties and also to bring the light fastness of different dyeings to a level which is higher overall, i.e., for example, to bring dyeings with dyes which produce light fastnesses which are weaker per se to the light fastness level of dyeings obtainable with dyes which produce light fastnesses which are very high per se. By sealing with certain sealing agents, for example based on nickel at the boiling temperature, a certain improvement in the light fastness can be achieved in some cases, but this is still insufficient in many cases, particularly for articles intended for external architecture, i.e. which are exposed to sunlight for a very long time.
It has now been found that the light fastness of adsorptive dyeings obtainable on aluminium oxide layers with certain dyestuffs (A) which, due to their too low light fastness, are usually considered as being unsuitable or not well suitable for the dyeing of aluminium oxide layers for the production of dyed external construction elements which will be subject to very long sunlight exposure, can be improved to a surprisingly high level by a cold sealing with a sealant (B) containing Ni
2+
and F
−
ions, as described in more detail below.
The invention relates to the process for the production of the dyed oxide layers, to the corresponding light fastness improvement agents, and to the substrates dyed in this way.
A first subject-matter of the invention is thus a process for the production of dyed oxide layers on aluminium or aluminium alloys by dyeing in an aqueous dyebath, rinsing with water and sealing, which is characterized in that the dyeing is carried out using at least one water-soluble anionic dye (A) which possesses at least one substituent and/or component combination with a ligand character that is capable per se of forming a nickel complex with nickel ions, and the sealing is carried out by cold sealing with at least one sealing agent (B) containing nickel ions Ni
2+
and fluoride ions F
−
.
The dyes (A) which can be employed in accordance with the invention generally belong to the series of those which are known for the dyeing of aluminium oxide layers or can be used for this purpose. They are anionic and preferably possess at least one sulpho group in the molecule. They are capable of forming complexes with nickel(II) ions, in particular labile nickel complexes. Correspondingly, the dyes (A) advantageously contain suitable available electron pairs in suitable orbital configurations and/or heteroatoms, in particular as occur in substituent and/or component combinations with a ligand character. In other words, substituent and/or component combinations with a ligand character which are capable of forming labile Ni complexes with nickel ions are present in (A). Such configurations are produced, for example, through combination of corresponding metallizable substituents which are able to bind the nickel ion in a labile manner, such as, for example, a hydroxyl group and a carboxyl group vicinal thereto, as are present in salicylic acid, or, in 1:1 metal complexes, especially copper complexes, heteroatomic moieties, in particular nitrogen atoms as ring members of a heterocyclic ring, only some or none of which participate in the copper complex formation, as present, for example, in copper phthalocyanine complexes (particularly copper complexes), and/or in copper complexes of monoazo dyes which contain a coupling component from the oxyquinoline or pyrazolone series as azo component. The salicylic acid groups are in particular those which are bonded to the remaining part of the dye molecule in the meta-position and/or para-position to the carboxyl group, preferably via at least one heteroatomic bridging unit. The following may be mentioned as examples of suitable dyes (A): sulpho group-containing phthalocyanine-copper complexes, salicylic acid group-containing, sulpho group-containing mono- and disazo dyes, salicylic acid group-containing, sulpho group-containing metal complexes of monoazo dyes complexed to the azo group (for example 1:1 Cu, 1:1 or 1:2 Cr, 1:2 Co complexes), and sulpho group-containing 1:1 metal complexes, particularly copper complexes, of monoazo dyes containing a coupling component from the oxyquinoline or pyrazolone series as azo component.
Representative examples are the dyes of the general formulae
in which X denotes hydrogen or a bond to FC,
m denotes 1 or 2,
n denotes a number from 1 to twice the total number of aromatic rings in the molecule,
M denotes hydrogen or a non-chromophoric cation
and FC denotes the (m+n)-valent residual chromophoric part of the dye,
in which R denotes C
1-4
-alkyl,
M denotes hydrogen or a non-chromophoric cation,
n denotes a number from 1 to twice the total number of aromatic rings in the molecule,
and DK denotes the radical of a diazo component,
and the ring B may optionally be further substituted, for example with C
1-4
-alkyl, and
in which M denotes hydrogen or a non-chromophoric cation,
n denotes a number from 1 to twice the total number of aromatic rings in the molecule
and DK denotes the radical of a diazo component.
Other sulpho group-containing dyes (A) from the 1:1 copper complex series may also be employed in the process according to the invention. By contrast, less suitable or unsuitable dyes are those which contain conjugated carbonyl groups and contain no salicylic acid groups (for example anthraquinone dyes), or 1:2 metal complexes which contain no salicylic acid groups. Suitable as (A) are particularly those dyes which, dyed on anodized aluminium and sealed with boiling water, give dyeings which have a light fastness of <7, determined in accordance with ISO specification No. 105 B02 (USA) (by dry exposure wi
Schöfberger Georg
Tscheulin Günther
Bisulca Anthony A.
Clariant Finance Limited
Einsmann Margaret
Hanf Scott E.
LandOfFree
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