JPS5845732A - Covering of support - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves contacting a support with a dispersion of a solid particle phase in a liquid phase and then baking to produce a refractory, oxidized film, wherein the dispersion has at least a second refractory oxide coating. The present invention relates to a method of providing a refractory oxide coating on a substrate, the method comprising: a refractory oxide component and a second refractory oxide component.

Coating a support with a refractory oxide by contacting the support with a dispersion in a liquid medium and subsequent baking is a well-known process and is carried out for various purposes. This is carried out, for example, in order to protect the support, or to provide a support material for the catalytically active material which is subsequently applied, or to provide the support with other properties. Examples of such methods in the art include: British Patent No. I, 1a90,977 (U.S. Patent No. 3.93'
, 1, No. 92), the specification describes dispersions containing sols of refractory carrier materials (e.g. A#20.), which may also contain powdered carrier materials, as well as catalytic dispersions It is described that it is used for preparing a support. British patent application publication tube 2. θ23,'I! ;3A (U.S. Patent No. '1.2
q7,21Ab) in the specification (e.g. Ce
a dispersion comprising a non-agglomerated sol (of O2 and 5102) and may optionally contain an agglomerated sol (e.g. of U203);
The use of dispersions thereof in coatings is also described. British patent application publication tube λ, 01>II, No. 372A (
(corresponding to U.S. Pat. No. 11.29/,070) (e.g. u 2 o 3, CeO2, Si O2
) and non-colloidal particulates (e.g. S, 03, C
A dispersion containing e0% SiO2) and its use for coating metal particles in a fluidized bed is described. U.S. Patent No. 3. ! /g, 2OA also describes in its Example 1 a dispersion comprising, inter alia, a sodium silicate solution and an aqueous alumina, and its use for the preparation of a catalyst support.

However, the above dispersions are not completely suitable for producing high purity coatings as required for certain catalytic and electronic applications.

The present invention successfully addresses the above problems and thereby extends the range of applications of coatings on supports obtained from dispersions.

The present invention involves contacting a support with a dispersion of a solid particulate phase in a liquid phase and then baking to produce a refractory oxide coating, the dispersion comprising at least a first refractory oxide component. A method for providing a refractory oxide coating on a support comprising a second refractory oxide component, the second refractory oxide component being obtained from a purifiable liquid or solid precursor and forming at least a portion of the solid phase, and wherein the second refractory oxide component is obtained from a purifiable liquid or solid precursor and forming a portion of the solid phase;
Alternatively, there is provided a method characterized in that the liquid phase is a purifiable liquid precursor that constitutes at least a part of the liquid phase.

By using components obtained from or constituted by purifiable precursors, it is possible to obtain coatings of higher purity than can be obtained with prior art methods. Thus, in order to achieve the desired purity in the final product, purifiable liquid precursors, conveniently suitable organic compounds, can be purified by distillation and purifiable solid precursors by recrystallization.

The refractory oxide component obtained from purifiable liquid or solid precursors can be, for example, alumina, titania, silica or zirconia, of which alumina is particularly preferred. An example of a suitable form of alumina is boehmite. This is because it can be prepared from refinable precursors such as triethylaluminum. This triethylaluminum can be converted to boehmite by the following reaction known in the art: Triethylaluminum is a liquid that can be purified by distillation.

Another suitable form of alumina is alumina made by firing alum. Myonokun is a purifiable alumina precursor that can be purified by recrystallization.

Other suitable forms of alumina are aluminum 5ec-
Alumina made by controlled hydrolysis of liquid alkoxyaluminum compounds such as butoxide. Aluminum 5ec-butoxide is a commercially available liquid and purifiable precursor that can be purified, for example, by vacuum distillation.

A suitable form of silica is silica made by hydrolysis of liquid depleted silicon compounds, such as tetraethoxysilane, which is purified by distillation.

The refractory oxide component obtained from a purifiable liquid or solid precursor need not necessarily be the refractory oxide itself, but may be, for example, a water-containing form thereof.

An example of a purifiable liquid precursor that makes up at least a portion of the liquid phase is a water-soluble silicone, such as a silicone glycol copolymer. An example of such a copolymer is dimethicone copolyol, which has the structural formula: dimethicone copolyol and related materials are surfactants and are commercially available under the trade name Dow Corning lqO, by Dow Corning Go4ration. Dow Corning / 9.
7 and Hi/Ukoning Q,! -! ; Sold as 097 liquid.

Such water-soluble silicones can be mixed with water and used as a liquid phase.

Other examples of purifiable liquid precursors that constitute at least a portion of the liquid phase are liquid alkyl silicates such as tetraethylorotosilicate and ethyl polysilicate.

The purifiable liquid precursor described above, which constitutes at least a portion of the liquid phase, can be purified by distillation.

As used herein, "precursor" means something that can be converted into a refractory oxide, such as silica, as a result of a baking process. In this respect, the water-soluble silicones described above are particularly suitable, since they can be easily decomposed into silica by heating and contribute little or no impurities. They also have surfactant properties, which aid in uniform application of the dispersion onto the support. However, silicones with limited solubility in water, ie in the form of aqueous emulsions, can also be used as long as they are miscible with the other components of the dispersion. Quaternary ammonium silicates can be used as such precursors alone or in combination with silicones.

The dispersion may also contain other ingredients, such as wetting agents, for example as coating aids. The rheology of the dispersion used can be adjusted by the inclusion of substances such as hydrophilic polymers, so that application of the dispersion onto the support can be carried out, for example, by doctor blading techniques. A wide variety of materials are suitable for this purpose as long as they are compatible with the other components of the dispersion.

The first refractory oxide component and the second refractory oxide component may become different refractory oxides even if they become the same refractory oxide after baking, as long as they can be identified with each other in the dispersion. It's okay to be. For example, dispersion F12 may contain alumina derived from different precursors to constitute the refractory oxide component.

The support may be a non-metallic support or a metal support such as steel. Coatings can be provided on the support for a number of purposes, for example to protect the support, for electrical purposes or as a support material for catalytically active substances that are applied immediately,
It can be applied by methods known in the art.

The present invention is specifically described below, by way of example only: Example 1 Colloidal boehmite (!; 20OS') was dispersed to prepare a dispersion. The boehmite was prepared from triethylaluminum by the method described above. A flat non-metallic support was immersed into the dispersion, removed, dried and baked at 7000° C. for 1 hour. A coherent coating was obtained on the support.

EXAMPLE A dispersion was prepared as follows: o, ty DC/9
Quaternary ammonium silicate containing aq, gt 3 (Quram2 from Emery Industries)
20), lθ, oy-@Dlspural” alumina powder (manufactured by Condea Chemle) was stirred into the solution.The dispersion was used to coat a support as described in Example 1.The alumina was prepared from triethylaluminum by the method described above. 1 Example 3 The method of Example 1 was repeated except that the dispersion was made as follows: SO containing oc193 of θ, /z ,t
It's Quram 220 during tt, gy's Llnde
A alumina powder (manufactured by Union Carbide) was mixed in with stirring. A uniform coating was obtained. The alumina powder was prepared by roasting alum and was raw.

Example 1 The procedure of Example 1 was repeated except that the dispersion was made as follows. S, 0 in DC193 of /9.751-?
of Dlspural powder was stirred in. A thick coating was obtained.

Example S The method of Example 1 was repeated except that the dispersion was made as follows. 30.01 Dispural powder was mixed with t22.0 Poc7011 silicone fluid (DowCo
rnlng) and the mixture was allowed to internalize for several minutes.

Example 6 Aluminum 5ec-cytoxide (Br1tish D
RugHouses Jlmlted) was added to excess water and hydrolyzed to aluminum hydroxide by centrifugation of the hydroxide, which was then washed first with methanol and then with water. The wet glut contained about 1% alumina by weight. The dal was stirred until a thick paste was obtained and a silica precursor, e.g. 5llester O5 (Mon-
(manufactured by Santo Limlted) was stirred and mixed into the (St fester).
It seems to help with the mixing of In this example,
Generation variance [Fi-2-! ;X S 102,? 7
6! ;%u203 equivalents. The dispersion was then used to coat a support as described in Example 1.

Si fester is technically a mixture of tetraethylorthosilicate and ethyl polysilicate (ie, monomer+polymer).

Example 7 Aluminum 5ec-butoxide (Br1tis'h
(DrugHouses Llmitel) was hydrolyzed to aluminum hydroxide by adding it to excess water.

The hydroxide was centrifuged, washed several times with water, stirred until a homogeneous yeast was obtained, and then used as challenge material.

The above product in the form of wet glue (10OV, //wt% A-e203 was mixed with alumina powder (particle size 0.3 μm: Ll
nde) and the resulting dispersion was used as a coating material as described in Example/. “Example
゛-゛The wet hydroxytoggle prepared as in Example B was stirred until it became a single layer, and then added to the Linde at λ1.
Alumina powder and! Q t) m' meta〉-ru/S
Part 3 Water/Ko 0゛薗 3 A mixture of tetraethylene silicate (tetraethyl ↓ silane) (e, o, +, manufactured by Ltd.) So! Blended with n3. Its 5102 content was qnia weight %. A coating was made from the dispersion as described in Example 1-.

Continuation of page 1 Priority claim March 3, 1982 [phase] United Kingdom (G
B) ■6271 0 Inventor: Nidward Sitney Lane, London, UK, Nystafrew 1 Y. 4 Kewpie Charles Z. 11 Second Street @ Inventor: Thomas Camble Prentice, London, UK, Nystafrew 1 Y. 4 Kewpie・Charles Z. 2nd Street 11-0 Inventor: David Leslie Segal, London, UK Nistafrew 1Y4Kewpie Charles Z. Second Street 0 Inventor: David Camble Sammon, London, UK 1 Y 4 Kewpie Charles Ze 11 2nd Street

Claims (1)

What is claimed is: contacting the fl+ support with a dispersion of a solid particle phase in a liquid phase and then baking to produce a refractory oxide coating, the dispersion comprising at least a primary refractory oxide component and A method of providing a refractory oxide coating on a support comprising a second refractory oxide component, wherein the second refractory oxide component is obtained from a purifiable liquid or solid precursor and the solid comprising at least a portion of the solid phase, and wherein the second refractory oxide component is obtained from a purifiable liquid or solid precursor and comprising at least a portion of the solid phase; A method characterized in that a purifiable liquid precursor constitutes at least part of the phase. (2) The method according to claim (1), wherein the first refractory oxide component is alumina. (Claim No. 31, wherein the alumina is made by hydrolysis of a liquid organoaluminum compound.
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