Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2000-10-10
2003-02-25
Green, Anthony J. (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S410000, C106S412000, C106S413000, C106S494000, C106S495000, C106S496000, C106S497000, C106S498000
Reexamination Certificate
active
06524382
ABSTRACT:
The present application relates to a process for the manufacture of pigmented vitreous materials, as well as to pigmented vitreous materials, characterized by the use of soluble pigment precursors and preferably the absence of significant amounts of dispersants. These pigmented vitreous materials can be used as coloured materials for any known purposes. Examples of uses are layers on beverage bottles, TV screens and other glass items.
As pigmented vitreous materials, there are understood materials comprising a crosslinked matrix of polycondensated transition metal oxides or hydroxides (generally referred to in the literature as “sol-gels”), wherein organic pigment particles are entrapped. The matrix may consist essentially of metal-oxygen-metal links, or may also comprise organic links between the metal atoms. The matrix in particular also can be a hybrid organic-inorganic system, for example an ormocer or a ceramer. All such materials are well-known in the art, and are described for example in many patents and patent applications, such as EP 354 465, EP 426 037, EP 504 926 and EP 590 740, as well as also in reviews articles, reference books and technical encyclopedia.
EP 648 770 and EP 648 817 disclose carbamate-functional, soluble chromophors which can be converted to the corresponding pigments by heating them to relatively high temperatures, with the ensuing elimination of the carbamate radicals. These compounds are suitable for the mass colouring of polymers and, according to EP 654 711, for the colouring of resists and of polymer coats to which they are applied. Compounds of the same type but with improved properties are known for example from EP 742 556, WO 98/32802, WO 98/45757, WO 98/58027 and WO 99/01511.
U.S. Pat. No. 5,243,052 discloses carbonates of quinophthalones, which are of limited solubility and can be used in heat-sensitive recording systems. The leuco dye is embedded within a polymer, preferably in polyethyloxazoline.
EP 504 926 discloses a coating solution composition for forming glass gel thin film, color glass gel filter, and display device using the same, wherein colorant material particles are incorporated together with not less than 0.01 weight % of a dispersant, preferably from 5 to 100 parts by weight with respect to 100 parts by weight of the coloring material. The colorant material particles are such of dyes or pigments, for example azo yellow and red, perylene, perinone, dioxazine, thioindigo, isoindolinone, quinophthalone, quinacridone, phthalocyanine or inorganic pigments. The glass gel thin film is formed at the temperature of 100 to 300° C.
Further, similar sol-gel processes and compositions using organic pigment dispersions are disclosed in JP-A-07/207186, JP-A-08/175823, JP-A-09/239311 and JP-A-10/204296.
The dispersant is disclosed to strengthen the gel film layer, so that the negative influence of the colorant particles would be compensated. However, the sol-gels of the prior art do still not match satisfactory today's high requirements in workability, strength, homogeneity, light, heat and moisture stability, transparency and coloristics. The colorant is not entirely sealed within the inorganic gel, so that it is exposed to oxygen and moisture and partially extracted by chemicals used in the manufacture of articles comprising the gels. High concentrations of colorant furthermore require high amounts of dispersants, leading to further impaired properties. A key limitation is that organic pigments of different classes cannot satisfactory be used together because they require different, often antagonistic dispersants.
The instant invention surprisingly leads to remarkably improved properties through the use of soluble organic pigment precursors which thermally split to insoluble organic pigments. Highly unexpected, the pigment particles are strongly bonded to the gel especially in the absence of an additional dispersant. Surfactants may nevertheless be added, for example to improve the surface quality, but advantageously they are only optional and do not need to be adapted to the pigment. Although the real mechanism is not elucidated yet, it is believed that the pigment's solubilizing groups do interfere with the gel formation mechanism so that the gel's affinity to organic pigments is improved, instead of just splitting off into an olefin and carbon dioxide as is generally the case in solution.
Hence, the invention relates to a process for making a pigmented vitreous material from a liquid or dissolved transition metal compound, wherein the liquid or dissolved transition metal compound reacts to form crosslinks between the liquid or dissolved transition metal atoms in the pigmented vitreous material, characterized in that the solution also comprises a dissolved compound of the formula
A(B)
x
(I),
in which
x is an integer from 1 to 8,
A is the radical of a chromophor of the quinacridone, anthraquinone, perylene, indigo, quinophthalone, indanthrone, isoindolinone, isoindoline, dioxazine, azo, phthalocyanine, diketopyrrolopyrrole or 3-methylidene-2,3-dihydro-indol-2-on series which is attached to x groups B via one or more heteroatoms selected from the group consisting of N, O and S and forming part of the radical A,
B is hydrogen or a group of the formula
where at least one group B is not hydrogen and, if x is from 2 to 8, the groups B can be identical or different, and
L is any suitable solubilizing group,
and the vitreous material is heated so that the compound of the formula (I) is transformed into a pigment of the formula A(H)
x
(II), in which x has the same meaning as in formula (I).
Transition metals are well-known in the art and may for example be aluminium, zinc, zirconium, titanium, iron, cobalt and nickel, and very particularly silicium. The liquid or dissolved transition metal compounds are also well-known in the art and may for example be an alkoxide or a mixed oxide/alkoxide, which may in addition contain further substituents, for example C
1
-C
4
alkyl groups or halogens.
The transformation of the compound of the formula (I) into a pigment of the formula A(H)
x
(II) by heating may be performed simultaneously with the liquid or dissolved transition metal compound's crosslinking reaction, or as a separate final step.
Besides the product's excellent properties, the process of the invention has also the advantage that it is much faster than the prior art, due to the fact that a dispersion step is not necessary. Moreover, the reaction can be conducted at higher temperature and at higher pigment contents in the substantial absence of dispersants, without impairing the transparency, hue and chroma.
The reaction is generally performed in the way, that all ingredients are first mixed to form a composition which can be applied as desired and heated to regenerate the pigment. The composition may also contain effective amounts of a catalyst, for example an acid or a precursor which forms an acid upon heating. The acid or precursor may be added at the time of the composition's preparation, or preferably just before the composition's application.
An effective amount of a catalyst is any quantity suitable to start or accelerate the reaction. Catalysts and the suitable quantities thereof are well-known in the art. Examples are mineral acids, such as hydrochloric acid or nitric acid, Lewis acids, such as boron trifluoride, organic acids, such as formic, acetic or oxalic acid, or the like, preferably with a pK
a
of 3 or lower.
In addition or even instead of catalysts, it is also well-known to use a light source or to heat the mixture to a mild temperature, for example about 50 to 80° C., in order for the crosslinking reaction (gelation) to start.
Before or during gelation, it is possible to work the composition into the desired form by usual means, for example coating layers by spin coating or by printing methods, such as for example screen or inkjet printing. In analogy to the resist technology (disclosed for example in EP 654 711), it is also possible to perform the crosslinking only in
Bujard Patrice
De Keyzer Gerardus
Hall-Goulle Veronique
Hao Zhimin
Nagasue Hitoshi
Ciba Specialty Chemicals Corporation
Crichton David R.
Green Anthony J.
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