Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
1999-11-08
2001-09-04
Wood, Elizabeth D. (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S494000, C106S495000, C106S496000, C106S497000, C106S498000, C501S080000
Reexamination Certificate
active
06284036
ABSTRACT:
The present invention relates to a process for pigmenting a porous sintered material comprising boride, carbide, silicide, nitride or phosphide compounds by applying a solution of a soluble pigment derivative to the non-coloured sintered material and regenerating the organic pigment by heating, whereby the organic pigment is deposited into the sintered material's pores, as well as to the new pigmented sintered materials themselves.
Sintered materials are commonly prepared at extremely high temperatures. Thus, it is not feasible to colour them by adding a colorant before the sintering step, and the only way for colouring them is to soak them with a solution of a dye.
However, this leads to unexpected technical problems with sintered materials comprising boride, carbide, silicide, nitride or phosphide compounds. The color saturation is very weak, and many coloured sintered materials are no more satisfactory heat-stable. When the coloured sintered material is heated to high temperatures, the dye sublimes or apparently reacts with the boride, carbide, silicide, nitride or phosphide compounds, so that it fades while the chemical and mechanical properties of the sintered material itself may be impaired.
It has now been found, that certain soluble compounds can be used for the purpose of pigmenting sintered materials comprising boride, carbide, silicide, nitride or phosphide compounds with surprisingly better results. The pigmented sintered materials have strong, optically uniform colorations with high colour saturation (chroma), fast to weathering, light and wear, which are highly stable to high temperatures, even in the presence of additional chemicals, such as for example humidity, oils or fats.
WO 98/58027 discloses the use of carbamate-functional, soluble chromophores which can be converted to the corresponding pigments by being heated to relatively high temperatures, with the ensuing elimination of the carbamate radicals, for the pigmentation of porous materials in general. However, none of the disclosed materials needs to be heat-stable, and the exemplified material wood is in fact quite heat-sensitive.
The present invention accordingly provides a process for pigmenting a porous sintered material comprising a boride, carbide, silicide, nitride or phosphide compound with an organic pigment by
(a) treating said sintered material with a solution or melt of a soluble pigment precursor such that at least part of the pigment precursor enters its pores, and
(b) forming said organic pigment within the pores, through thermal fragmentation of the pigment precursor that has entered the pores of the sintered material in accordance with treatment (a), by means of heating,
wherein said soluble pigment precursor is a compound of the formula (I) or a mixture of 2 or more compounds of the formula (I)
A(B)
x
(I),
in which x is an integer from 1 to 8,
A is the radical of a chromophore of the quinacridone, anthraquinone, perylene, indigo, quinophthalone, indanthrone, isoindolinone, isoindoline, dioxazine, azo, phthalocyanine or diketopyrrolopyrrole 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.
Porous sintered materials comprising a boride, carbide, silicide, nitride or phosphide compound are well-known to the skilled artisan as well as the methods and conditions for their preparation. They are also disclosed in numerous patents and in the technical literature, to which express reference is hereby made. Preferred are sintered materials prepared at a temperature of from 250° C. to 1500° C., most preferred at from 400° C. to 1000° C., especially from 400° C. to 800° C.
The boride, carbide, silicide, nitride or phosphide compound may be any boride, carbide, silicide, nitride or phosphide which is sufficiently stable in air saturated with humidity at temperatures from 0 to 50° C., so that its half-life period under such conditions is at least 1 day. Known boride, carbide, silicide, nitride or phosphide compounds are for example the borides of Al, Ca, Ti, V, Cr, Fe, Cu, Sr, Nb, Mo, Ba, Ta, W and Ce, the carbides of B, Si, Ti, V, Fe, Ni, Zr, Nb, Hf, Ta, W and Al, the nitrides of Si, V, Cr, Fe, Ga, Ge, Zr, Nb, Ta, W, Al, Mg and B, phosphorus oxynitride, the silicides of B, Mg, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Mo, Ru, Pd and W, and the phosphides of Ti, Cr, Mn, Fe, Co, Ni, Cu, Zr, Mo, Cd, In, W, Pt and Au.
Preferred boride, carbide, silicide, nitride or phosphide compounds are such, which are colourless, white, translucent or only slightly gray coloured, most preferred colourless or white and at least partially translucent.
The porous sintered material may consist of one or more boride, carbide, silicide, nitride or phosphide compounds, or also comprise other materials, such as metallic particles or inorganic particles, for example metal oxides or hydroxides, especially as binders. It may be of any shape and size, for example platelets, tubes, filaments, hollow or massive bodies.
The concentration of the organic pigment may be low or high, depending of the desired colour saturation. A low concentration of the organic pigment in the sintered material leads to pastel tints, while a high concentration leads to higher saturations. Generally, the sintered material to be pigmented by the process of this invention is sufficiently porous for any coloristically desired quantity of soluble pigment precursor to be incorporated.
The skilled artisan will obviously recognize that the instant process may be combined with any other known further treatment. For certain purposes, it is for example possible to improve the pigmented sintered material's long-term stability by sealing or any other finishing treatment known in the field. The instant pigmented sintered materials may be substituted with great coloristic advantages for non-coloured or differently coloured sintered materials. In particular, any additional feature known for the prior art sintered materials may also be used in combination with the instant pigmented sintered materials.
The instant pigmented sintered materials may of course be used for any known purpose, with the only difference that it is pigmented. They are particularly useful wherever colour is essential, for example for distinguishing them or also for purely decorative purposes.
Sintered materials considered as porous are those, which have cavities within their physical shell, which may be partly or totally filled with a gas, for example air, or with a liquid, for example water. Preferably, the pores extend at least in part to the surface of the material. The volume of the pores is preferably at least 5% relative to the volume of the geometric shell of the material. Particularly preferably, the volume of the pores is from 10 to 80% relative to the volume of the geometric shell of the material. Preferably, the cross-section of the pores is so fine that by virtue of capillary force an aqueous liquid does not flow out under gravity. The average cross-section of the pores is particularly preferably from 1·10
−18
, more preferably from 1·10
−17
m
2
, up to about 10
−8
m
2
, more preferably up to 4·10
−14
m
2
, most preferred up to 2·10
−15
m
2
, determined at a transverse section through the material, by dividing the total pore area by the number of pores.
Introducing the pigment precursor into the pores of the sintered material is effected by applying a solution or melt of the pigment precursor to the sintered material using any desired, known method, for example by spraying or impregnation in a bath. The application temperature can be an elevated temperature but is judiciously kept low enough for the dissolved or melted pigment precursor not to undergo any, or any significant, decomposition during the minimum time required for the application.
Suit
Hao Zhimin
Homma Seiji
Schacht Hans-Thomas
Ciba Specialty Chemicals Corporation
Crichton David R.
DiVerdi Michael
Wood Elizabeth D.
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