Coating processes – Base supplied constituent – Resin or rubber base
Reexamination Certificate
1999-10-29
2001-11-13
Beck, Shrive P. (Department: 1762)
Coating processes
Base supplied constituent
Resin or rubber base
C427S226000, C427S399000, C148S246000, C148S272000, C148S279000
Reexamination Certificate
active
06316057
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the coating of a metal surface, metal-oxide surface, metal-salt surface, silicon surface and high-molecular-weight aquoxide organic surface.
BACKGROUND OF THE INVENTION
Numerous procedures have been established to coat surfaces, such as CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), plasma coating, the Langmuir-Bodgett-Technique and adsorption or reaction from solution. These methods lead to the formation of thin or ultrathin films (including monolayers).
The average thickness of thin and ultrathin films ranges up to several micrometers. For example, self assembled films are well studied, i.e. films which assemble spontaneously from homogeneous solution at surfaces. For example, diphosphates form self-assembled multilayers (Ulman, A.; Chem. Rev. 1996,96,1533 and Ulman, A.; MRS Bulletin 1995,6,46). Self-assembled monolayers form among others, with organosulfur compounds, which typically contain a thiol, disulfide or thioether group (loc.cit). Such organosulfur compounds exhibit a strong affinity to transition metal surfaces. Their coordination to gold, silver, copper, platinum, mercury, iron, gallium arsenide and colloidal gold surfaces has already been studied (loc.cit). Organoselenium compounds, such as organoselenols on gold (Samant, M. G.; Brown, C. A.; Gordon II, J. G.; Langmuir 1992,8,1615), and fatty acids, e.g., n-alkanoic acids on Al
2
O
3
, Ago, Cuo and glass (Ulman, A; Chem. Rev. 1996,96,1533 and Ulman, A.; MRS Bulletin 1995,6,46) also form self-assembled monolayers. The adsorption of alkanenitriles (Steiner, U. B.; Caseri, W. R.; Suter, U. W.; Langmuir 1992,8,2771), phosphines, triphenylamine, triphenylarsine, triphenyistilbine, triphenylbismuthine (Steiner, U. B.; Neuenschwander, P.; Caseri, W. R.; Suter, U. W.; Stucki, F.; Langmuir 1992,8,90), imides (Steiner, U. B.; Caseri, W. R.; Suter, U. W.; Rehahn, M.; Schmitz, L.; Langmuir 1993,9,3245) and tricosylisocyanide (Bain, C. D.; Eval, J.; Whitesides, G. M.; J.Am.Chem.Soc. 1989,111,7155) is also described. Monolayers with covalent C—Si bonds are obtained on H—Si(111) or H—Si(100) silicon surfaces with the help of peroxides (Ulman,A.; Chem. Rev. 1996,96,1533). Organosilicon compounds, which typically contain a chlorosilane, alkoxysilane or aminosilane group also form self-assembled monolayers on substrates such as silicon oxide, aluminum oxide, quartz, glass, mica, zinc selenide, germanium oxide, and gold (Ulman, A.; Chem. Rev. 1996,96,1533 and Ulman, A.; MRS Bulletin 1995,6,46).
OBJECT OF THE INVENTION
The object of the present invention is to provide a process for the coating of surfaces, which allows the preparation of well-adhering thin and/or ultrathin layers (including monolayers) on materials as different as metals, metal-oxides, metal-salts, silicon-comprising materials and high-molecular-weight aquoxide-comprising organic materials.
DESCRIPTION OF THE INVENTION
The invention is based on the discovery, that reagents with Si—H, Sn—H or Ge—H groups form layers on metal surfaces, metal-oxide surfaces, metal-salt surfaces, silicon-comprising surfaces and high-molecular-weight aquoxide-comprising organic surfaces in presence of a platinum metal as activator in the form of a compound or in metallic form. The reagents are solids or liquids, which are applied in bulk or in a medium in liquid, pasty or solid form. The reagents can be applied, for example, as solution, as emulsion, as suspension, as foam or as spray. According to the technical terminology, the elements Ru, Rh, Pd, Os, Ir and Pt are known as platinum metals. Preferred are platinum compounds, including those that are reduced with silanes to platinum(O) or those that already contain platinum(O). In metallic form, the platinum metals are present preferentially as particles of atomic, colloidal or larger dimensions.
Platinum compounds which can be reduced with silanes to Pt(O) or which are already present in the oxidation state O have been described, for example, by Caseri, W. R.; Dissertation, ETH Zürich, 1988. Examples for such platinum compounds are cis-dichlorobis(styrene)platinum(II), trans-dichlorobis(styrene)-platinum(II), platinum(II) chloride, platinum(II) bromide, potassium tetrachloroplatinate(II), platinum(O)divinyltetramethyidisiloxane, Zeise's salt, triphenylphosphineaecetylacetonatochloroplatinum(II), dichloro-&mgr;
2
-dichlorobis(styrene)diplatinum(II) or bis(cyclooctadiene)platinum(O).
Transition metal compounds that react with, e.g., Si—H, Sn—H or Ge—H bonds via oxidative addition are known in organometallic chemistry. This reaction is used, e.g. for the hydrosilylation, hydrostannylation and hydrogermylation. The hydrosilylation reaction describes the addition of organic and inorganic silicon hydrides to multiple bonds, e.g. in olefins, acetylenes, ketones, imines, and nitriles (Bogdan, M.; “Comprehensive Handbook on Hydrosilylation”, Pergamon Press, Oxford 1992). On the basis of Speier's results (Speier, J. L.; Webster, J. A.; Barnes, G. H., J.Am.Chem.Soc. 1957,79,974; Speier, J. L.; Adv.Organomet.Chem. 1979,17,407) and their own observations of the first examples of oxidative addition reactions of silanes to transition metal compounds, Chalk and Harrod proposed a homogeneously catalyzed mechanism for the hydrosilylation reaction (Chalk, A. J.; Harrod, J. F.; J.Am.Chem.Soc. 1965,87,16). There are also heterogeneously catalyzed hydrosilylation reactions, where the transition metal compound is reduced to a colloid and the resulting colloid is catalytically active. For example, hexachloroplatinic acid is reduced to colloidal platinum, which is catalytically active (Lewis, L. N.; Lewis, N.; J.Am.Chem.Soc. 1986,108,7228). Hydro-stannylation and hydrogermylation reactions describe analogously the addition of their organic and inorganic hydrides to multiple bonds.
The above mentioned references describe reactions with multiple bonds. According to the invention surprisingly it was found that a reaction takes place between the solid phase of the material of the surface to be coated and the reagent, where the desired strongly adhering coating is obtained in the presence of the activator.
In U.S. Pat. No. 5,215,801, a crosslinking reaction of vinyl- and hydride-functionalized silicones is described. This is a classical hydrosilylation reaction with a platinum catalyst. The silicone to be vulcanized is filled with SiO
2
, which is added among other factors to improve the adhesive properties. A reaction between Si—H groups and the solid phase of the material of the surface to be coated in the presence of an activator is not striven for.
In DE-A 19 14 411 a gas phase reaction or a growth from the gas phase, respectively, is described. Compounds containing, e.g., Si—H are evaporated, i.e., transferred into the gas phase. The reactive gaseous substances are activated with catalysts (e.g. Pt). Subsequently the activated substances must react either with a reagent (e.g., ammonia) or they must be decomposed. Only the reacted or decomposed substance forms the desired layer.
Also, in U.S. Pat. No. 4,873,119 a gas phase reaction is described. Here, the production of amorphous semiconductors originating from compounds with Si—H or Ge—H groups is described. The Si—H or Ge—H compounds are transferred into the gas phase, activated with, e.g., platinum and decomposed by, e.g., glow discharge, heat (incl. pyrolysis) or light (incl. IR, UV) to amorphous semiconductors and deposited on a surface.
An advantage of the present invention to coating procedures such as CVD and PVD is the fact that reagents do not have to be transferred into the gaseous phase but can be applied in liquid, pasty or solid form.
A special advantage of the procedure according to this invention is the variety of different substrates that can be coated. Suitable surfaces to be coated, i.e., substrates, are metals, metal-oxides, metal-salts, alloys (for example steels), silicon compounds (for example silicon wafers or silicate glasses), ceramics (for example silicate ceramics, oxide ceramics, brick,
Caseri Walter R.
Hirayama Martina
Suter Ulrich W.
Beck Shrive P.
Crockford Kirsten A.
Dubno Herbert
Global Surface Aktiengesellschaft
Myers Jonathan
LandOfFree
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