JP7324186B2 - Curable surface protective coating composition, method for its preparation, and its application to metal substrates and resulting coated metal substrates - Google Patents

Description

The present invention relates to the field of surface protective coating compositions, e.g. conversion and passivation coatings, more specifically curable coating compositions derived from alkoxysilanes and for the coating of metal substrates therewith. Regarding the method.

Many surface protective coating compositions have been developed over the years for application to various types of surfaces for the purpose of providing corrosion and/or wear resistance. For example, chromium and heavy metal phosphate conversion coatings have been used to prepare metal surfaces prior to painting. However, growing concerns about the toxicity of chromium and the polluting effects of chromates, phosphates, and other heavy metals discharged as industrial waste into streams, rivers, and other waterways have led to the need for alternatives to such metal coating compositions. We are promoting to seek

One type of surface protective coating composition that has resulted from these efforts to develop non-chromium, non-phosphate and non-heavy metal based metallic coating compositions is derived from alkoxysilanes. Curable coating compositions derived from alkoxysilanes continue to attract a high level of interest in the metal industry, and although some formulations have gained wide commercial acceptance, the storage stability of the uncured compositions is poor. , and room for improvement in one or more of those properties that remain important to metal manufacturers and processors, such as adhesion, flexibility, corrosion resistance, abrasion/scratch resistance, and optical clarity properties of the cured composition. remains quite a bit.

According to one aspect of the present invention, curing for surface protecting applications of substrates such as metals, metal alloys, metallizations, metals with one or more protective layers or one of the metallizations A protective surface coating-forming composition is provided, the coating-forming composition comprising:
(i) at least one alkoxysilane selected from the group consisting of formulas A and B:
(X-R ¹ ) _a Si(R ² ) _b (OR ³ ) _4-(a+b) Formula A
(R ³ O) ₃ Si—R ¹ —Si(OR ³ ) ₃ Formula B
wherein X is an organic functional group, more particularly mercapto, acyloxy, glycidoxy, epoxy, epoxycyclohexyl, epoxycyclohexylethyl, hydroxy, episulfide, acrylate, methacrylate, ureido, thioureido, vinyl, allyl, -NHCOOR ⁴ or -NHCOSR ⁴ groups, wherein ^R4 is a monovalent hydrocarbyl group containing 1 to about 12 carbon atoms, more specifically 1 to about 8 carbon atoms, thiocarbamate, dithiocarbamate, ether, thioether , disulfide, trisulfide, tetrasulfide, pentasulfide, hexasulfide, polysulfide, xanthate, trithiocarbonate, dithiocarbonate or isocyanurate group, or another —Si(OR ³ ) group, where R ³ is as defined in
Each R ¹ is a linear, branched or cyclic divalent radical of 1 to about 12 carbon atoms, more specifically 1 to about 10 carbon atoms, and most specifically 1 to about 8 carbon atoms. divalent hydrocarbon groups such as, but not limited to, methylene, ethylene, propylene, isopropylene, butylene, isobutylene, cyclohexylene, arylene, aralkylene or alkarylene groups, which are valent organic groups such as O, S, optionally containing one or more heteroatoms, such as the non-limiting examples of NR ⁴ , wherein R ⁴ is hydrogen or an alkyl group of 1 to 4 carbon atoms;
Each ^R2 is independently an alkyl, aryl, of 1 to about 16 carbon atoms, more specifically 1 to about 12 carbon atoms, even more specifically 1 to 4 carbon atoms; an alkaryl or aralkyl group optionally containing one or more halogen atoms, more particularly fluorine atoms,
each ^R3 is independently an alkyl group of 1 to about 12 carbon atoms, more specifically 1 to about 8 carbon atoms, still more specifically 1 to 4 carbon atoms; ;
subscript a is 0 or 1, subscript b is 0, 1 or 2, and a+b is 0, 1 or 2; and
The amount of the alkoxysilane of formula A when subscript a is 0 or 1, subscript b is 0, 1 or 2, and a+b is 2 is from 0 to about 8 in percent by weight;
the amount of the alkoxysilane of formula A when a+b is 0 is from 0 to about 15 weight percent of the coating-forming composition;
the total amount of the alkoxysilane of Formula A wherein subscript a is 0 or 1, subscript b is 0 or 1, and a+b is 1, and alkoxysilane of Formula B from about 8 to about 40; weight percent, and the total amount of alkoxysilanes of formulas A and B does not exceed about 50, preferably about 45, more preferably about 40 weight percent of the coating-forming composition;
(ii) at least one metal oxide in particulate form, wherein the amount of metal oxide is from about 5 to about 50 weight percent of the coating-forming composition;
(iii) at least one water-miscible organic solvent;
(iv) at least one acid hydrolysis catalyst;
(v) water; and (vi) optionally at least one condensation catalyst,
wherein the coating-forming composition has a viscosity of from about 3.0 to about 7.0 cStks, more specifically from about 4.0 to about 5.5 cStks, still more specifically from about 4.5 to about 5.0 cStks at 25°C. It has a viscosity in the range of 0 cStks.

In the present invention, the viscosity is measured according to the DIN 53015 standard "Viscometry- Measurement of Viscosity by Means of the Rolling Ball Viscometer by Hoeppler" using a Haake DC10 temperature control unit and ball set 800-0182, in particular a diameter of 15.598 mm and a weight of 4.5 mm. Ball No. 4282 g with a density of 2.229 g/cm ^{3 .} Measured at 25°C using a Hoeppler FallingBall Viscometer Model 356-001 with 2.

In one embodiment of the invention, the at least one alkoxysilane (i) selected from the group consisting of formulas A and B can also be hydrolysis and condensation products thereof.
Such products include oligomers of alkoxysilanes (i) selected from the group consisting of formulas A and B. They are prepared by hydrolysis and condensation of alkoxysilanes (i) selected from the group consisting of formulas A and B. That is, alkoxysilyl groups react with water, liberating the corresponding alcohols, and the resulting hydroxysilyl groups then condense to form Si--O--Si (siloxane groups). The resulting hydrolysis and condensation products or oligomers can be linear or cyclic polysiloxanes containing, for example, 2 to 30 siloxy units, preferably 2 to 10 siloxy units, and residual alkoxy groups.
Conditions for the amount of alkoxysilane (i) i.e. amount of alkoxysilane of formula A where subscript a is 0 or 1, subscript b is 0, 1 or 2 and a+b is 2 is from 0 to about 25 weight percent of the coating-forming composition;
the amount of the alkoxysilane of formula A when a+b is 0 is from 0 to about 15 weight percent of the coating-forming composition;
The total amount of the alkoxysilane of formula A and the alkoxysilane of formula B where the subscript a is 0 or 1, the subscript b is 0 or 1, and a+b is 1 is the coating-forming composition from about 8 to about 40 weight percent of the composition, and the total amount of alkoxysilanes of formulas A and B does not exceed about 50, preferably about 45, more preferably about 40 weight percent of the coating-forming composition;
It is understood that it also applies to the corresponding oligomers derived from the alkoxysilanes of formulas A and B.
Certain preferred examples of such oligomers include especially oligomeric glycidoxypropyltrimethoxysilane.

Further in accordance with the present invention, a) cooling a mixture of alkoxysilane (i) and a portion of the acid hydrolysis catalyst (iv) to form the above curable surface protective coating-forming composition;
b) adding metal oxide (ii) and water (v) to the cooled mixture of step (a);
c) adding to the mixture resulting from step (b) a water-miscible organic solvent (iii) and the remainder of the acid hydrolysis catalyst (iv);
d) heat the mixture resulting from step (c) to about 3.0 to about 7.0 cStks, more specifically about 4.0 to about 5.5 cStks, even more specifically about 4.0 cStks at 25°C; aging under conditions of elevated temperature for a period of time effective to provide a curable coating-forming composition having a viscosity within the range of 5 to about 5.0 cStks; Also provided is a process comprising, at any step, adding a condensation catalyst (vi) during that step or after that step.
metal oxide (ii) is selected from the group consisting of silica, alumina, titania, ceria, tin oxide, zirconia, antimony oxide, indium oxide, iron oxide, iron oxide and/or zirconia-doped titania and rare earth oxides; This process is particularly preferred if it is a colloidal suspension of at least one metal oxide, or if metal oxide (ii) is selected from a mixture of alumina and silica.

Yet in accordance with another embodiment of the present invention, there is also provided a process for forming the aforementioned curable surface protective coating-forming composition, comprising a) metal oxide (ii) and acid hydrolysis catalyst (iv). ) to a temperature of preferably from about -20°C to about 15°C, preferably from about -10°C to about 10°C, more preferably from about 0 to about 10°C;
b) adding alkoxysilane (i) (or a mixture thereof) to the cooled mixture of step (b);
c) allowing the mixture obtained in step c) to warm to room temperature (about 25° C.) (preferably either by allowing it to reach room temperature, for example overnight, or less preferably by supplying heat),
d) adding to the mixture obtained in step d) at least one water-miscible organic solvent (iii) and optionally a condensation catalyst (vi) and optionally one or more other optional components (vii) , obtaining a composition having a viscosity in the range of about 3.0 to about 7.0 cStks at 25°C. This process is particularly preferred when the metal oxide (ii) is selected from alumina-modified silica. Silica modified with alumina particles such as Levasil® 100S/45 (now: Levasil CS45-58P) (AkzoNobel) and Levasil® 200S/30 (now: Levasil CS30-516P) (AkzoNobel) and acetic acid (iv) are stirred in a flask. The mixture is cooled to 0-10° C. while the alkoxysilane (i) is added dropwise within 20-50 minutes. The mixture is stirred while the solution reaches room temperature. The next day, solvent (iii) such as alcohol, catalyst (vi), and flow additive (vii) are added. The entire mixture is stirred for at least 15 minutes to obtain a coating-forming composition.

According to yet another aspect of the present invention, a metal having a protective surface coating, i.e. a coating that imparts corrosion and/or wear resistance to the surface of an uncoated or precoated metal,
f) applying a coating of the aforementioned coating-forming composition to an uncoated or pre-coated surface of the metal;
g) removing at least some solvent (iii) from the applied coating of the coating-forming composition; and h) curing the solvent-less coating of the coating-forming composition to provide a corrosion-resistant and /or obtained by a coating process further comprising providing an abrasion resistant coating.

The curable coating-forming compositions of the present invention have excellent storage stability, and the cured surface protective coatings obtained therefrom exhibit high levels of corrosion and abrasion resistance, adhesion to metal surfaces, flexibility ( It tends to exhibit one or more functionally advantageous properties such as resistance to cracking or cracking due to flexing of metals), and resistance to acids and/or alkalis. In addition, the generally excellent optical clarity of the cured coatings herein allows them to demonstrate to good effect the aesthetically appealing qualities of the underlying substrate surface.

As used herein and in the claims, the following terms and expressions are to be understood to have the meanings indicated below.

The singular forms "a," "an," and "the" include plural forms, and reference to a particular numerical value includes at least that particular value unless the context clearly dictates otherwise.

Except as otherwise indicated in the examples or in the claims, all numerical values expressing amounts of materials, reaction conditions, durations, quantified properties of materials, etc. It should be understood that the term "about" modifies in all instances.

All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is merely intended to better describe the invention and, unless otherwise claimed, is beyond the scope of the invention. It does not impose any limitation.

No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

As used herein, the terms "comprising", "including", "containing", "characterized by" and their grammatical equivalents are , an inclusive or open-ended term that does not exclude additional, unlisted elements or method steps, but the more restrictive terms “consisting of” and “consisting essentially of” It will be understood to include the terminology as well.

Unless otherwise indicated, composition percentages are given in weight percentages.

It is understood that any numerical range recited herein includes all subranges within that range and any combination of the various endpoints of such ranges or subranges.

compounds disclosed and/or claimed herein, either explicitly or implicitly, as belonging to a group of structurally, compositionally and/or functionally related compounds, materials or substances; It will be further understood that reference to materials or substances includes individual representatives of the group and all combinations thereof.

The expression "coating-forming composition" is not itself a practical or useful coating composition, but a high quality, effective thermosetting composition for application to metal surfaces after the treatments detailed herein. It should be understood to mean a composition that forms a surface protective coating.

As used herein, the term "metal" should be understood to apply to metals themselves, metal alloys, metallizations, and metals or metallizations having one or more non-metallic protective layers. is.

"Hydrolytic condensation" means that one or more silanes in the coating composition-forming mixture are first hydrolyzed, followed by hydrolysis products and other hydrolyzed and/or non-hydrolyzed It means that the condensation reaction with the components continues.

A. Coating Forming Composition Components Alkoxysilane (i)
Alkoxysilanes (i) present in the coating-forming composition are one or more dialkoxysilanes, trialkoxysilanes and/or tetraalkoxysilanes of formula A above and/or one or more trialkoxysilanes of formula B , provided that at least one such trialkoxysilane is included therein.

Examples of dialkoxysilanes of Formula A include dimethyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, 3-cyanopropylphenyldimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, di(p-tolyl)dimethoxysilane, Bis(diethylamino)dimethoxysilane, bis(hexamethyleneamino)dimethoxysilane, bis(trimethylsilylmethyl)dimethoxysilane, vinylphenyldiethoxysilane, etc., and mixtures thereof.

As explained above, alkoxysilanes, including dialkoxysilanes, also include their hydrolysis and condensation products (oligomers).

Examples of trialkoxysilanes of formula A include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltripropoxysilane, n-propyltributoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, isooctyltriethoxysilane, vinyltrimethoxysilane , vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane, trifluoropropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxy Included are silanes, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, oligomers and mixtures thereof. Of these, methyltrimethoxysilane, octyltrimethoxysilane and glycidoxypropyltrimethoxysilane are particularly preferred.

As explained above, alkoxysilanes, including trialkoxysilanes, also include their hydrolysis and condensation products (oligomers).

Examples of tetraalkoxysilanes (ie, tetraalkylorthosilicates) of Formula A include tetramethoxysilane, dimethoxydiethoxysilane, tetraethoxysilane, methoxytriethoxysilane, tetrapropoxysilane, etc., and mixtures thereof.

Examples of trialkoxysilanes of Formula B include 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane, bis(trimethoxysilylpropyl)disulfide, bis(triethoxysilylpropyl). ) disulfide, bis(trimethoxysilylpropyl)tetrasulfide, bis(triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)amine, etc., and mixtures thereof is included.

metal oxide (ii)
Metal oxide component (ii) is generally in the form of particles, e.g. It is provided in the form of a range of roughly spherical or equiaxed particles. Average particle size is measured using Low Angle Laser Light Scattering (LALLS), in particular using the full Mie theory, in particular a Mastersizer 2000 or 3000 from Malvern Instruments.

Metal oxides (ii) are aqueous colloidal dispersions thereof, for example silica, alumina, titania, ceria, tin oxide, zirconia, antimony oxide, indium oxide, iron oxide, titania doped with iron oxide and/or zirconia, It is advantageously provided as an aqueous colloidal dispersion of metal oxides such as rare earth oxides, and mixtures and composite oxides thereof. Alternatively, metal oxide (ii) in powder form may be dispersed within the coating composition.

A preferred metal oxide (ii) is aqueous colloidal silica. Aqueous dispersions of colloidal silica that can be used to advantage in the present invention include those having average particle sizes ranging from about 20 to about 150 nm, preferably from about 5 to about 30 nm. Such dispersions are known in the art and commercially available, for example, Ludox® (Sigma Aldrich), Snowtex® (Nissan Chemical), and Bindzil®. (AkzoNobel), Nalco® colloidal silica (Nalco Chemical Company), Levasil® (AkzoNobel). Such dispersions are available in the form of acidic and basic hydrosols.

Both acidic and basic colloidal silica can be incorporated into the coating-forming composition of the present invention. Colloidal silica with low alkali content can provide more stable coating compositions and may therefore be preferred. Particularly preferred colloidal silicas include Nalco® 1034A (Nalco Chemical Company) and Snowtex® O40, Snowtex ST-033 and Snowtex® OL-40 (Nissan Chemical), Ludox® AS40 and Ludox® HS 40 (Sigma-Aldrich), Levasil 200/30 and Levasil® 200 S/30 (now Levasil CS30-516P) (AkzoNobel), and Cab-O-Sperse® A205 (Cabot Corporation).

When metal oxide (ii) is as defined in paragraphs [0030] through [0033], the total amount of alkoxysilanes of formulas A and B preferably does not exceed about 40 weight percent of the coating-forming composition.

In embodiments of coating-forming compositions according to the present invention, metal oxide (ii) is selected from mixtures of alumina and silica. Preferably, for said mixture, the weight ratio of alumina to silica ( _Al2O3 / _SiO2 ) is from about _1:99 to about 99:1, preferably from about 5:95 to about 90:10, more preferably from about 5:95 to about 75:25. Such mixtures are preferably prepared by mixing aqueous colloidal dispersions of alumina and silica. The use of a mixture of alumina and silica provides good adhesion to aluminum surfaces, very high wear resistance, good corrosion protection, heat resistance, acid resistance and alkali resistance.

In embodiments of the coating-forming composition according to the present invention, the metal oxide (ii) is selected from alumina-modified silica. In one embodiment, such alumina modified silica may be surface alumina modified silica. Such alumina-modified silicas are therefore sometimes referred to as Al ₂ O ₃ —SiO ₂ —core-shell particles. Also, in this embodiment, the metal oxide (ii) may advantageously be provided as an aqueous colloidal dispersion. The use of such alumina-modified silica or Al ₂ O ₃ —SiO ₂ —core-shell particles is particularly useful for protecting anodized aluminum parts of automotive exteriors, such as roof rails and trim parts, and is sensitive to high pH or Provides high corrosion resistance, high scratch resistance, and high heat resistance due to low pH liquids. The use of such alumina-modified silica in coating-forming compositions according to the present invention provides high scratch resistance under long-term highly acidic environmental conditions. Examples of alumina-modified ^silica include, ^for example, about Levasil® 100S/45 (now: Levasil CS45-58P) dispersion (45% in water) containing silica particles surface-modified with Al ₂ O ₃ with an average particle size of 30 nm, average particles about 17 nm Levasil types, such as Levasil® 200S/30 (currently Levasil CS30-516P) dispersion (30% in water) comprising sized Al ₂ O ₃ surface-modified silica particles.

In certain embodiments using alumina-modified silica, a mixture comprising at least two alumina-modified silicas having different average particle sizes can be used. For example, the weight ratio of alumina-modified silica with a smaller particle size (e.g., 10 to 25 nm) is greater than the amount of alumina-modified silica with a larger particle size (e.g., 26-40 nm), preferably uses a mixture of two silicas modified with alumina having different average particle sizes with a small/large ratio of from about 10:1 to about 1:2, preferably from about 10:1 to about 2:1 be able to. This method provides particularly high scratch resistance.

The amount of metal oxide (ii) incorporated into the coating-forming compositions herein is generally from about 5 to about 50, more specifically from about 10 to about 40, still more specifically from about 10 to about 40, based on the weight of the composition. may vary from about 10 to about 30 weight percent.

water-miscible organic solvent (iii)
Examples of water-miscible solvents (iii) that can be incorporated into the coating-forming composition of the present invention are methanol, ethanol, propanol, isopropanol, n-butanol, tert-butanol, methoxypropanol, ethylene glycol, diethylene glycol butyl ether, and Combinations of such alcohols. Other water-miscible organic solvents such as acetone, methyl ethyl ketone, ethylene glycol monopropyl ether, and 2-butoxyethanol can also be used. Typically these solvents are used in combination with water, the latter being associated with the metal oxide (ii) providing part or all of the water (v) and/or other components of the coating composition. Used with water.

The total amount of water-miscible solvent (iii) present in the coating-forming composition is, for example, about 10 to about 80, more specifically about 10 to about 65, more specifically about It can vary widely, such as from 10 to about 60, even more specifically from about 10 to about 50 weight percent. When the coating-forming composition comprises alumina-modified silica as the metal oxide (ii), the total amount of water-miscible solvent (iii) present in the coating-forming composition is, for example, about It can vary greatly from 40 to about 70, more specifically from about 50 to about 65 weight percent.

Acid hydrolysis catalyst (iv)
Any of the acidic hydrolysis catalysts heretofore used for hydrolysis of alkoxysilanes can be incorporated into the coating-forming compositions herein. Exemplary acid hydrolysis catalysts (iv) include sulfuric acid, hydrochloric acid, acetic acid, propanoic acid, 2-methylpropanoic acid, butanoic acid, pentanoic acid (valeric acid), hexanoic acid (caproic acid), 2-ethylhexanoic acid. , heptanoic acid (enanthic acid), hexanoic acid, octanoic acid (caprylic acid), oleic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, cyclohexylacetic acid, cyclohexenecarboxylic acid, benzoic acid, benzeneacetic acid, propanedioic acid (malonic acid ), butanedioic acid (succinic acid), hexanedioic acid (adipic acid), 2-butenedioic acid (maleic acid), lauric acid, stearic acid, myristic acid, palmitic acid, isoanoic acid, versatic acid (versatic acid), lauric acid, stearic acid, myristic acid, palmitic acid, isanoic acid, amino acids and mixtures thereof. The acid hydrolysis catalyst can be used neat or in the form of an aqueous solution.

The acid hydrolysis catalyst (iv) is most often present in the coating-forming composition of the present invention in an amount of from about 0.1 to about 5, more specifically about 0.5, based on the total weight of the coating-forming composition. It will be present in at least a catalytically effective amount, which can range from 5 to about 4.5, and more specifically from about 2 to about 4 weight percent. In certain embodiments, for example, when the coating-forming composition comprises silica modified with alumina as the metal oxide (ii), the amount of acid hydrolysis catalyst (iv) is also added to the total weight of the coating-forming composition. may range from about 0.1 to about 2 weight percent based on.

water (v)
The water component of the coating-forming composition herein is advantageously deionized (DI) water. A portion or all of the total water present in the coating composition-forming mixture is replaced by a portion of one or more other components of the mixture, such as an aqueous colloidal dispersion of metal oxide (ii), a water-miscible solvent ( iii), an acid hydrolysis catalyst (iv) an optional condensation catalyst (vi) and/or other optional ingredients (vii) as described below.

The total amount of water (v) is, for example, from about 5 to about 40, more specifically from about 5 to about 30, even more specifically from about 5 to about 15, by weight based on the total weight of the coating-forming composition. It can be within widely varying ranges, such as percent.

optional condensation catalyst (vi)
Optional condensation catalyst (vi) catalyzes the condensation of the partially or fully hydrolyzed silane components (a) and (b) of the coating-forming composition herein and thus functions as a curing catalyst.

The coating-forming composition can be cured in the absence of any condensation catalyst (vi), but efficient curing requires stronger conditions, such as the application of elevated temperatures (thermal curing) and/or prolonged curing. Additional curing times may be required, both of which may be desirable from a cost and/or productivity standpoint. In addition to providing a more economical coating process, use of optional condensation catalyst (vi) generally results in improved shelf life of the coating-forming composition.

An example _of a condensation catalyst (vi) that _may optionally _be present in the ^{coating -} forming composition herein ^is a tetra butylammonium carboxylate, wherein ^R5 is selected from the group consisting of hydrogen, alkyl groups containing from 1 to about 8 carbon atoms, and aromatic groups containing from about 6 to about 20 carbon atoms . In preferred embodiments, ^R5 is a group containing about 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl or isobutyl. Compared to the more active types of condensation catalysts (v), such as mineral acids and alkali metal hydroxides, the aforementioned tetrabutylammonium carboxylates are somewhat milder in their catalytic activity and the coating-forming compositions containing them It tends to optimize the shelf life of the product. Exemplary tetrabutylammonium carboxylate condensation catalysts of the above formula include tetra-n-butylammonium acetate (TBAA), tetrabutylammonium formate, tetra-n-butylammonium benzoate, tetra-n-butylammonium-2-ethyl hexanoate, tetra-n-butylammonium-p-ethylbenzoate and tetra-n-butylammonium propionate. With respect to the effectiveness and suitability of the present invention, preferred condensation catalysts are tetrabutylammonium carboxylate, tetra-n-butylammonium acetate (TBAA), tetra-n-butylammonium formate, tetra-n-butylammonium benzoate, tetra-n-butylammonium benzoate, -n-butylammonium-2-ethylhexanoate, tetra-n-butylammonium-p-ethylbenzoate, and tetra-n-butylammonium propionate, tetramethylammonium acetate, tetramethylammonium benzoate, tetrahexylammonium acetate , dimethylanilium formate, dimethylammonium acetate, tetramethylammonium carboxylate, tetramethylammonium-2-ethylhexanoate, benzyltrimethylammonium acetate, tetraethylammonium acetate, tetraisopropylammonium acetate, triethanol-methylammonium acetate, diethanol dimethylammonium acetate, monoethanoltrimethylammonium acetate, ethyltriphenylphosphonium acetate, TBD acetate (1,5,7-triazabicyclo[4.4.0]des-5-ene (TBD)), and two thereof It is a combination of the above.

Of the above tetrabutylammonium carboxylate condensation catalysts, tetra-n-butylammonium acetate and tetra-n-butylammonium formate are generally preferred, and tetra-n-butylammonium acetate is more preferred.

When utilized, the condensation catalyst (vi) can be present in the coating-forming composition herein in at least a catalytically effective amount, such as from about 0.0001 to about 1 weight percent based on its total weight.

other optional ingredients (vii)
One or more other optional ingredients (vii) are suitable for inclusion in the coating-forming compositions herein.

For example, the coating-forming composition can also include one or more surfactants that function as leveling agents or flow additives. Examples of suitable surfactants include fluorinated surfactants such as Fluorad® (3M); silicone polyethers such as Silwet® and CoatOSil® (Momentive Performance Materials, Inc.); and silicone surface additives such as polyether modified silicones such as BYK-302 (BYK Chemie USA). The coating compositions herein can also contain UV absorbers such as benzotriazole, benzophenone, dibenzylresorcinol, and the like. Preferred UV absorbers are those capable of co-condensation with silanes, specific examples of which include 4-[gamma-(trimethoxysilyl)propoxyl]-2-hydroxybenzophenone, 4-[gamma-(triethoxy silyl)propoxyl]-2-hydroxybenzophenone and 4,6-dibenzoyl-2-(3-triethoxysilylpropyl)resorcinol. When the preferred UV absorbers capable of co-condensing with silanes are used, thorough mixing prior to application of the thermosetting coating compositions herein to the surface of the metal ensures that the UV absorbers are mixed with other UV absorbers. It is important to co-condense with the reactive species. Co-condensing the UV absorbers prevents degradation of coating performance that can be caused by leaching of free UV absorbers into the environment during weathering.

The coating-forming compositions herein also contain one or more antioxidants such as hindered phenols (e.g., dyes such as Irganox® 1010 (Ciba Specialty Chemicals), methylene green, methylene blue, etc.), titanium dioxide, phosphorus Fillers such as zinc oxide, barite, aluminum flakes, and plasticizers such as dibutyl phthalate can be included.

B. Forming the Coating-Forming Composition In forming the thermosetting coating composition of the present invention, cooling a portion of the mixture of alkoxysilane (i) and acid hydrolysis catalyst (iv) followed by ) and aging the resulting mixture under predetermined conditions of elevated temperature and time is from about 3.0 to about 7.0 cStks, in another embodiment more specifically Specifically, it results in a thermosetting composition having a viscosity ranging from about 4.0 to about 5.5 cStks, and more specifically from about 4.5 to about 5.0 cStks in yet another embodiment.
Cooling can be performed using, for example, an ice bath, ice/NaCl mixtures, or dry ice/isopropanol mixtures. More specifically, alkoxysilane (i) and acid hydrolysis catalyst (iv) are placed in a glass vial and the mixture is placed in an ice bath to cool while monitoring the temperature with an external thermometer. Cooling of the mixture of alkoxysilane (i) and acid hydrolysis catalyst (iv) is from about -20°C to about 15°C, preferably from about -10°C to about 10°C, more preferably from about 0°C to about 10°C. Temperature is preferred.

In the first step of the process of forming the thermosetting coating compositions herein, a trialkoxysilane of formulas A and/or B, an optional dialkoxysilane and/or tetraalkoxysilane of formula A, and an acid hydrolyzate are A mixture of about 10 to about 40 percent of the total amount of cracking catalyst (iv) is cooled to within a temperature range of about -20°C to about 15°C, preferably about -10°C to about 10°C. While in the cooling state, metal oxide (ii), eg aqueous colloidal silica, is slowly added to the mixture.

After the addition of metal oxide (ii), the temperature of the cooled mixture is brought to or near ambient temperature with constant stirring for about 2 to about 10 days, more specifically about 5 to about 8 days, For example, from about 20°C to about 30°C. During this period of continuous stirring, the alkoxysilane component (i) of the mixture undergoes an initial level of hydrolysis, followed by condensation of the resulting hydrolyzate.

When the metal oxide (ii) is selected from alumina modified silica, it is preferred to cool these formulations for several hours/overnight, eg from about 2 to about 10 hours.

In the second stage of the process of forming the thermosetting coating composition herein, the water-miscible solvent (iii) and the remaining acid hydrolysis catalyst (iv) are added to the present ambient temperature reaction medium, e.g. added under continuous stirring over a period of from about 5 to about 24, more specifically from about 8 to about 15 hours, during which time further hydrolysis of the silane and/or partial hydrolyzate and the thus-formed Condensation of the hydrolyzate occurs.

When metal oxide (ii) is selected from alumina modified silica, it is preferred to directly add the entire amount of acid hydrolysis catalyst (iv) first, so acid hydrolysis catalyst (iv) at this point is is not added.

Addition of a portion of the acid hydrolysis catalyst (iv) in a first stage and the remainder of the acid hydrolysis catalyst (iv) in a second stage results in a curable coating composition within the viscosity range set forth above. can get. The rate of hydrolysis and condensation reactions is dependent on the concentration of the acid hydrolysis catalyst (iv) and the pH of the reaction mixture. The final pH of the reaction mixture is advantageously maintained from about 2 to about 7, more specifically from about 4 to about 6. Acid hydrolysis catalyst (iv) is added in two stages to maintain the pH at each stage. The first portion of acid hydrolysis catalyst (iv) is added, for example dropwise, so as to prevent agglomeration and precipitation of metal oxide particulates (ii), whereby alkoxysilane component (i) undergoes hydrolysis and metal Functionalizing the oxide particles (ii). The silanization of the metal oxide fine particles (ii) makes the pH of the mixture nearly neutral.

When metal oxide (ii) is selected from alumina modified silica, a pH range of about 3 to about 4, such as about 3.5 to about 3.8 is typically achieved without additional pH adjustment. be.

An acid hydrolysis catalyst (iv) may be added in a second stage to maintain the final pH of the mixture and to control condensation of silanols and inhibit gel formation, resulting in a relatively long shelf life. after storage at ambient temperature for, for example, about 15 days or more, more specifically about 20 days or more, even more specifically about 30 days or more, less than about 5% by weight of its total weight, preferably about 2 A coating-forming composition is obtained that contains less than about 1% by weight of gel, more preferably less than about 1% by weight. In certain embodiments, storage at temperatures ranging from about 0 to about 15°C, preferably from about 5 to about 10°C may be suitable.

If employed, the optional condensation catalyst (vi) is in at least a catalytically effective amount during, after, or during any of steps (a)-(d) of preparing the curable coating composition. can be added. The amount of optional condensation catalyst (v) is, for example, from about 0.01 to about 0.5 weight percent, more specifically from about 0.05 to about 0.2 weight percent, based on the total weight of the coating-forming composition. % can vary greatly.

The optimum amount of residual silanol is obtained by accelerating the condensation reaction during aging, as explained in more detail below. Once the desired viscosity level is obtained, the curable coating composition can be applied to the desired substrate to produce a uniform, clear, hard coating thereon (1 kg load as described in Table 5 below). steel wool wear resistance test at ).

Following this additional hydrolysis period, the optional condensation catalyst (v) and one or more other optional components (vii) are advantageously added for a further period of time, for example from about 1 to about 24 hours. It can be added to the reaction mixture under continuous stirring. The resulting reaction mixture is now ready for aging.

Aging of the aforementioned coating composition-forming mixture is carried out at elevated temperature for a period of time that has been experimentally determined to result in a viscosity within the above range of about 3.0 to about 7.0 cStks.

If the metal oxide (ii) is selected from alumina modified silica, aging is usually not required.

Achieving such a viscosity results in a curable coating composition with good to excellent cured coating properties. Low viscosity can lead to decreased hardness of the coating film and post-curing that occurs with continued exposure of the coating. High viscosity can lead to cracking of the coating film during curing and subsequent exposure conditions.

For many coating composition-forming mixtures, viscosities within the range of about 3.0 to about 7.0 cStks can be obtained in an air oven, for example, at a temperature of about 25 to about 100° C. for about 30 minutes to about 1 day, more specifically heating the coating-forming mixture, typically at a temperature of about 25 to about 75° C. for about 30 minutes to about 5 days, and even more particularly at a temperature of about 25 to about 50° C. for about 3 to about 10 days; can be achieved by Hydroxyl-containing hydrolyzable silanes are partially hydrolyzed when less than an equivalent amount of water reacts with the hydrolyzable silyl groups. A silane is considered partially hydrolyzed when the percent hydrolysis is in the range of about 1 to about 94 percent. The hydroxyl-containing hydrolyzable silane is considered substantially completely hydrolyzed when the percent hydrolysis is in the range of about 95 to about 100 percent. Partially hydrolyzed hydroxyl-containing hydrolyzable silanes have excellent stability in aqueous solutions, because the R ¹ —O—Si group terminates the polymerization reaction of silanol condensation, leaving the hydroxyl-containing hydrolyzable This is because it maintains a low average molecular weight oligomeric composition derived from the silane. Lower average molecular weight oligomeric compositions adsorb more uniformly on metal substrates, resulting in better adhesion.

C. Coating application and curing procedure

With or without the further addition of additional solvent, the coating-forming composition of the present invention typically has a It has a solids content of 20 to about 30 weight percent. The pH of the coating composition will often be in the range of about 3 to about 7, more specifically about 4 to about 6.

When metal oxide (ii) is selected from alumina modified silica, the pH of the coating composition will often be in the range of about 3 to about 4, such as about 3.5 to about 3.8. Become.

The curable coating composition can be coated onto a metal substrate with or without a primer, preferably without a primer.

Suitable metals include steel, stainless steel, aluminum, anodized aluminum, magnesium, copper, bronze, alloys of each of these metals, and the like, where anodized aluminum is characterized by its inherent corrosion resistance and strength pairing. It is a particularly desirable substrate because of its weight ratio.

The coating-forming composition can be applied to metal surfaces or other substrates using any conventional or other known techniques such as spraying, brushing and flow coating. Dip coating is also possible. The wettability, or thickness of the newly applied coating, may vary over a fairly wide range, such as from about 10 to about 150, more specifically from about 20 to about 100, even more specifically from about 40 to about 80 microns. can vary over As-applied coatings of such thicknesses when dry generally range in thickness from about 3 to 30, more specifically from about 5 to about 20, and more specifically from about 10 to about 15 microns, respectively. to provide a cured coating with a high hardness.

When metal oxide (ii) is selected from alumina modified silica, a dry coating thickness (DFT) of typically about 2 to about 10 microns, preferably about 3 to about 7 microns is prepared.

As the coating dries, solvent (iii) and other volatiles evaporate, and over a short period of time, e.g., on the order of 15 to 30 minutes, the applied coating becomes tack-free to the touch, resulting in coating It can be appreciated that the layer/film is ready for curing advantageously utilizing conventional or other known thermal curing procedures whose operational requirements are well known in the art. For example, thermally accelerated curing can be performed within a temperature regime of about 80 to about 200° C. for a period of about 30 to about 90 minutes to provide a cured optically clear hard protective coating on the substrate metal. can.

The cured coating resulting from the coating-forming composition of the present invention may be in direct contact with a metal surface, may serve as the sole coating thereon, may overlay one or more other coatings, and/or Or it may itself have one or more other coatings over it. In addition to imparting corrosion and/or wear resistance to the metal substrate, the cured coating composition may also function as an aesthetic coating, where it is the sole or ultimate coating on the metal substrate. constitute the outer coating.

The advantages of the coating-forming composition of the present invention over known alkoxysilane-based coating-forming compositions are the specific combination of starting components and their amounts, and the unique process by which the coating-forming composition is obtained, particularly its separate cooling, Not only the exceptional storage stability in the present invention, which is attributed to the split addition of hydrolysis catalyst and the aging step, but also its various applications of metals and metallized surfaces, and the high reliability of cured coatings. It also has uniform characteristics.

As previously indicated, the cured coating composition of the present invention exhibits high levels of its adhesion to metal substrates, corrosion resistance, flexibility (resistance to cracking and cracking), abrasion/scratch resistance and It exhibits outstanding properties, including optical clarity, and the latter is a particularly sought-after property that will result in the cured coating composition additionally functioning as a decorative coating.

Comparative example 1
Comparative Example 1 shows a curable coating-forming composition prepared according to Burger et al. US Pat. No. 6,695,904 and applied to an anodized aluminum panel 15 cm long, 4 cm wide and 4 mm thick.

A mixture of 62.0 grams of methyltrimethoxysilane, 18.1 grams of tetraethoxysilane, and 23.13 grams of aqueous colloidal silica (40 weight percent suspension) was prepared with 1.3 grams of 37 weight percent sulfuric acid as an acid hydrolysis catalyst. Add dropwise at -5°C. The mixture was continuously stirred at 20° C. for 1 hour to obtain a coating composition. Within hours the reaction mixture gelled. However, after 1 hour an attempt was made to flow coat the mixture to a uniform thickness of about 10-15 microns onto an anodized aluminum substrate at a temperature of 23°C and 40% RH. After allowing the flow coating volatiles to evaporate with a flash-off time of 25 minutes, the coating was cured at 130° C. for 1 hour.

The resulting cured coating was opaque, showed extensive cracking, and delaminated indicating little, if any, adhesion to the underlying anodized aluminum surface.

A sample of the coating composition aged at 50°C for 24 hours gelled completely and a sample of the coating composition kept at about 23°C gelled completely within 24 to 48 hours. Due to its instability, the viscosity of the coating composition could not be measured.

Examples 1-15 (using colloidal silica as metal oxide (ii))
Examples 1-15 illustrate the preparation of a coating-forming composition of the present invention and on an anodized aluminum panel 15 cm long, 4 cm wide and 4 mm thick and a stainless steel panel 15 cm long, 10 cm wide and 1 mm thick. Their performance as cured coatings is described.

The starting ingredients for the curable coating-forming compositions of Examples 1-15 are set forth in Table 1 below.

The general procedure used to form the curable coating-forming compositions of Examples 1-15 is set forth in Table 2 below.

Using the starting materials noted in Table 1 and the general preparation procedure described in Table 2, the curable coating-forming compositions of Examples 1-15 were prepared from the mixtures shown in Table 3 below. .

The viscosities of the coating-forming compositions of Examples 1, 3 and 15 shown in Table 4 below were measured according to the DIN 53015 standard "Viscometry- Measurement of Viscosity by Means of the Rolling Ball Viscometer by Hoeppler" using a Haake DC10 temperature control unit and a ball set 800. -0182, in particular ball No. 15.598 mm in diameter, 4.4282 g in weight and 2.229 g/cm ³ in density. Measured at 25°C using a Hoeppler FallingBall Viscometer Model 356-001 with 2.

The general procedure for applying the curable coating-forming compositions of Examples 1-15 to anodized aluminum and stainless steel panels and curing the coatings thereon was as follows.
Coating Procedure Application of a coating layer having a thickness of about 10 microns can be performed by any suitable means such as dip, flow or spray coating. Dip coating was used to apply an approximately 10 micron thick layer of the coating-forming composition to the anodized aluminum panels, and flow coating was used to apply a coating of this thickness to the stainless steel panels.
Curing Procedure After applying the coating to the anodized aluminum and stainless steel substrates, the volatiles evaporated at about 23° C., forming a tack-free coating layer within about 25 minutes. The coated panel was then baked in a hot air oven at 130° C. for 45-60 minutes to produce a fully cured transparent hardcoat on the metal surface.

Testing of the coated metal panels was performed as described in Table 5 below.

Coating performance data are shown in Tables 6-9 below.




Examples 16 to 25 (using a mixture of silica and alumina particles as metal oxide (ii))

Coating formulations were prepared by either of the following procedures.
One-pot procedure for coating formulation:
A glass bottle was charged with acetic acid and trialkoxysilane. After cooling the reaction mixture to 0°C with an ice bath, the mixture of silica nanoparticles and water was added dropwise to the cooled mixture of silane and acetic acid, maintaining the temperature below 10°C. The mixture was then allowed to stir for about 1-2 hours. Alumina nanoparticle dispersion was added to the mixture, allowed to stir for 12-14 hours, and the temperature of the solution slowly increased to room temperature. The alcohol and remaining acetic acid were then added and the TBAA catalyst and flow additive were added followed by stirring for about 12 hours. After this the formulation was aged in a hot air oven at 50° C. for 5 days before being coated on the metal surface.

Two-pot procedure for coating formulation:
In this method, the coating solution can be prepared by separately reacting the alkoxysilane with different nanoparticles. This method may be a better option than the one-pot procedure for compositions that tend to precipitate nanoparticles in the formulation. However, this method can generally be used for coating compositions having any ratio of two different nanoparticles. In this method, acetic acid and trialkoxysilane were placed in a glass vial. After cooling the reaction mixture to 0°C with an ice bath, the mixture of silica nanoparticles and water was added dropwise to the cooled mixture of silane and acetic acid, maintaining the temperature below 10°C. The mixture was then allowed to stir for about 16 hours during which time the temperature of the solution slowly rose to room temperature. In a separate vial, a portion of the alkoxysilane (preferably a 1:1 weight ratio of silane to nanoparticles) and the nanoparticles (alumina) were mixed together and left to stir at room temperature for about 16 hours. After this, both solutions were mixed together at room temperature and kept stirring for 1-2 hours. The alcohol and remaining acetic acid were then added and the TBAA catalyst and flow additive were added followed by stirring for about 12 hours. After this, the formulations were aged in a hot air oven at 50° C. for about 5 days before coating onto metal surfaces.

General procedure for coating metal surfaces:
The coating composition is a thermoset single layer optically clear protective coating applied directly to the anodized aluminum surface. Application of thin layer coatings as thin as about 10 microns has been achieved by dip/flow/spray coating. After coating the aluminum substrate, the volatiles evaporate under ambient conditions (approximately 20-25° C., 40±10% RH) to form a tack-free coating layer within 25-30 minutes. After rinsing with solvent, the coated panel was baked in a hot air oven at 130-200° C. for 30-60 minutes to obtain a fully cured transparent hardcoat on the metal surface.

Test method (Examples 16-25)
Coating Appearance: This test is done by visual inspection. To pass, the coating must be smooth, glossy, optically clear, and free of coating defects.

Initial Adhesion: Crosshatch adhesion test is performed according to standard procedure ASTM D 3359. All coatings must pass 5B to be accepted.

Crockmeter Abrasion Resistance Test: This test is performed by AATCC Crockmeter CM-5 instrument using a 5 cm x 5 cm (Atlas) green cloth for 10 cycles (1 cycle = rub back and forth); distance: 100 mm; Force: done at 9N (automatically applied). To pass this test, there should be no visible scratches on the surface after the test.

Heat resistance: The coated panel is kept in a hot air oven at 160°C for 24 hours. To pass, there must be no adhesion loss, delamination, or cracks.

Hydrochloric acid resistance test: The coated panel is immersed in a hydrochloric acid (HCl) acid solution of pH 1.0 for 10 minutes. After exposure, the panel is removed from the solution, rinsed with DI water, and dried at ambient conditions. To pass, there must be no softening, adhesion loss, delamination, cracking or corrosion of the coating film.

Alkali resistance test: The coated panel is immersed in pH 13.5 sodium hydroxide buffer solution for 10 minutes. A buffer solution is prepared by mixing appropriate weights of sodium hydroxide, sodium phosphate decahydrate, sodium chloride, and deionized water. After exposure, the panel is removed from the solution, rinsed with DI water, and dried at ambient conditions. To pass, there must be no softening, adhesion loss, delamination, cracking or corrosion of the coating film.

Sulfuric acid resistance _test : The coated panel is immersed in pH 2.1 _H2SO4 solution for 5 days. After exposure, the panel is removed from the solution, rinsed with DI water, and dried at ambient conditions. To pass, there must be no softening, adhesion loss, delamination, cracking or corrosion of the coating film.

Corrosion resistance test - Kesternich test (acid rain simulation): This test is carried out according to DIN 50017 up to 3 cycles. To pass this test, the coating shall not exhibit softening, delamination, adhesion loss, change in visual appearance, or other coating defects.

Corrosion resistance test: Kesternich test (acid rain simulation)
Examples 19, 23, 24 and 25 were subjected to the Kesternich test and all passed the test.

As is evident from these tests, the inventive compositions of Examples 16-25 containing silica and alumina particles all exhibited good coating properties such as adhesion, abrasion and pH resistance tests (HCl and NaOH buffers). offer. In particular, these examples also provide very good results with respect to scratch resistance, pH resistance tests including sulfuric acid resistance, and the Kesternich test.
Examples 26 to 30 (Al ₂ O ₃ —SiO ₂ —core-shell particles as metal oxide (ii))

Preparation of Coating Composition A mixture of core-shell particles Levasil 100S/45 and Levasil 200S/30 and acetic acid is stirred in a flask. The mixture is cooled to 0-10° C. while the silane is added dropwise within 20-50 minutes. Stir the mixture until the solution reaches room temperature. The next day, alcohol, catalyst and flow additives are added. The entire mixture is stirred for at least 15 minutes.

Coating Procedure After preparation, the clear coating composition was applied directly to the anodized aluminum with a layer thickness of 2 μm to 8 μm. Application of the coating composition was accomplished by dip/flow or spray coating. After coating the anodized aluminum substrate, the solvent was rinsed off for 2-20 minutes to give a tack-free coating layer. The coated substrate is cured in a hot air oven at 130°C to 200°C for 30 minutes to 2 hours to obtain a complete cure.

Table 15: Test Results for Examples 26-30 The following tests and test procedures were performed on anodized aluminum parts.

SO ₂ lab test transferred from DIN 50018-2,0S: 0.67 wt% SO ₂ solution in a 5 L bottle in a water bath at 40°C. The coated sample is placed in this solution on the bottom while the top is subjected to the _SO2 atmosphere. According to the test specification, the coating should not change optically after 5 days.

Alkali resistance according to TL182: No change in appearance after the following series of tests with the same components in the temperature range of 23°C to 35°C.
a) 10 double rubs under 1 kg load b) 10 minutes immersion in pH 1 solution (0.1 molar hydrochloric acid) c) rinse with water and dry d) aged at 40°C for 1 hour then allowed to cool e) 10 minute immersion in pH 13.5 solution (12.7 g caustic soda, 4.64 g sodium phosphate dodecahydrate, 0.33 g sodium chloride; all dissolved in 1 liter of water)

48-hour salt spray test (CASS test) according to DINEN ISO 9227

The table below summarizes the results from different coating compositions.

Although the invention has been described above with reference to specific embodiments thereof, many variations, modifications and variations can be made without departing from the inventive concept disclosed herein. is clear. Accordingly, it is intended to embrace all such alterations, modifications and variations that fall within the spirit and broad scope of the appended claims.

Claims (41)

A coating-forming composition comprising:
(i) Formulas A and B
(X-R ¹ ) _a Si(R ² ) _b (OR ³ ) _4-(a+b) Formula A
(R ³ O) ₃ Si—R ¹ —Si(OR ³ ) ₃ Formula B
or at least one alkoxysilane selected from the group consisting of hydrolysis and condensation products thereof:
wherein X is an organic functional group;
each R ¹ is a linear, branched or cyclic divalent organic group of 1 to 12 carbon atoms, optionally containing one or more heteroatoms;
each ^R2 is independently an alkyl, aryl, alkaryl or aralkyl group of 1 to 16 carbon atoms, optionally containing one or more halogen atoms;
each R ³ is independently an alkyl group of 1 to 12 carbon atoms;
subscript a is 0 or 1, subscript b is 0, 1 or 2, and a+b is 0, 1 or 2; and subscript a is 0 or 1, subscript the amount of the alkoxysilane of formula A where b is 0, 1 or 2 and a+b is 2 is from 0 to 25 weight percent of the coating-forming composition;
the amount of alkoxysilane of formula A when a+b is 0 is from 0 to 15 weight percent of the coating-forming composition;
The total amount of the alkoxysilane of formula A and the alkoxysilane of formula B where the subscript a is 0 or 1, the subscript b is 0 or 1, and a+b is 1 is the coating-forming composition from 8 to 40 weight percent of the coating-forming composition, and wherein the total amount of alkoxysilanes of formulas A and B does not exceed 50 weight percent of the coating-forming composition;
(ii) at least one metal oxide in particulate form selected from a mixture of alumina and silica, or alumina modified silica , wherein the amount of metal oxide is from 5 to 50 weight percent of the coating-forming composition; is;
(iii) at least one water-miscible organic solvent;
(iv) at least one acid hydrolysis catalyst;
(v) water and (vi) optionally at least one condensation catalyst;
A coating-forming composition having a viscosity in the range of 3.0 to 7.0 cStks at 25°C. 2. The coating-forming composition of claim 1, wherein the total amount of alkoxysilanes of formulas A and B does not exceed 45 weight percent of the coating-forming composition. 2. The coating-forming composition of claim 1, wherein the total amount of alkoxysilanes of formulas A and B does not exceed 40 weight percent of the coating-forming composition. In the alkoxysilanes of formula A, a is 1 and the organic functional group X is mercapto, acyloxy, glycidoxy, epoxy, epoxycyclohexyl, epoxycyclohexylethyl, hydroxy, episulfide, acrylate, methacrylate, ureido, thioureido, vinyl, allyl. , —NHCOOR ⁴ or —NHCOSR ⁴ group, where R ⁴ is a monovalent hydrocarbyl group containing 1 to 12 carbon atoms, thiocarbamate, dithiocarbamate, ether, thioether, disulfide, trisulfide, tetrasulfide , a pentasulfide, hexasulfide, polysulfide, xanthate, trithiocarbonate, dithiocarbonate, or isocyanurate group, or another —Si(OR ³ ) group, where R ³ is as previously defined; 4. A coating-forming composition according to any one of claims 1-3. In the alkoxysilanes of formula B, R ¹ is a divalent hydrocarbon group containing at least one heteroatom selected from the group consisting of O, S and NR ⁴ , where R ⁴ is hydrogen or from one 5. A coating-forming composition according to any preceding claim, wherein the alkyl group is of 4 carbon atoms. The at least one alkoxysilane (i) is a trialkoxysilane of Formula A, a trialkoxysilane of Formula B, a subscript a being 0 or 1, a subscript b being 0 or 1, and a+b being 1. 6. A coating-forming composition according to any preceding claim, selected from at least one member of the group consisting of silanes and mixtures of trialkoxysilanes of formulas A and B. dialkoxysilanes of Formula A wherein the subscript a is 0 or 1, the subscript b is 0, 1 or 2, and a+b is 2, wherein each of the subscripts a and b is 0 7. Any of claims 1-6, comprising at least one alkoxysilane (i) selected from at least one member of the group consisting of tetraalkoxysilanes of A, and mixtures of dialkoxysilanes and tetraalkoxysilanes of formula A. The coating-forming composition according to . Trialkoxysilanes of formula A are methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyl tripropoxysilane, n-propyltributoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, isooctyltriethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, ethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane, trifluoropropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3 -glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane, and the trialkoxysilane of Formula B is 1,2-bis(trimethoxy silyl)ethane, 1,2-bis(triethoxysilyl)ethane, bis(trimethoxysilylpropyl)disulfide, bis(triethoxysilylpropyl)disulfide, bis(trimethoxysilylpropyl)tetrasulfide, bis(triethoxysilylpropyl) ) is at least one member selected from the group consisting of tetrasulfide, bis(3-triethoxysilylpropyl)amine and bis(3-trimethoxysilylpropyl)amine. Coating-forming composition. Metal oxide (ii) is selected from the group consisting of silica, alumina, titania, ceria, tin oxide, zirconia, antimony oxide, indium oxide, iron oxide, titania doped with iron oxide and/or zirconia, and rare earth oxides. 9. A coating-forming composition according to any preceding claim, which is a colloidal suspension of at least one metal oxide. The metal oxide (ii) is selected from a mixture of alumina and silica, wherein said mixture has a weight ratio of alumina to silica ( _Al2O3 / _SiO2 ) of 1:99 to ₉₉ :1. Item 10. The coating-forming composition according to any one of Items 1 to 9 . 11. The coating-forming composition of claim 10 , wherein the mixture of alumina and silica has an alumina to silica weight ratio ( _Al2O3 / _SiO2 ) of _5:95 to 90:10. 11. The coating-forming composition of claim 10 , wherein the mixture of alumina and silica has an alumina to silica weight ratio ( _Al2O3 / _SiO2 ) of _5:95 to 75:25. 13. A coating-forming composition according to any preceding claim, wherein the water-miscible solvent (iii) is at least one member selected from the group consisting of alcohols, glycols, glycol ethers and ketones. The at least one acid hydrolysis catalyst (iv) is sulfuric acid, hydrochloric acid, acetic acid, propanoic acid, 2-methylpropanoic acid, butanoic acid, pentanoic acid (valeric acid), hexanoic acid (caproic acid), 2-ethylhexanoic acid, Heptanoic acid (enanthic acid), hexanoic acid, octanoic acid (caprylic acid), oleic acid, linoleic acid, cyclohexanecarboxylic acid, cyclohexylacetic acid, cyclohexenecarboxylic acid, benzoic acid, benzeneacetic acid, propanedioic acid (malonic acid), butanedioic acid selected from the group consisting of acid (succinic acid), hexanedioic acid (adipic acid), 2-butenedioic acid (maleic acid), lauric acid, stearic acid, myristic acid, palmitic acid, isoanoic acid, versatic acid, and amino acids and wherein ^R5 consists of hydrogen, an alkyl group containing from 1 to 8 carbon atoms, and an aromatic group containing from 6 to 20 carbon atoms. at least one condensation catalyst (vi) selected from the group consisting of tetrabutylammonium carboxylates of the formula [(C ₄ H ₉ ) ₄ N] ⁺ [OC(O)-R ⁵ ] ^- , selected from the group 14. The coating-forming composition of any of claims 1-13 , comprising: Condensation catalyst (vi) includes tetra-n-butylammonium acetate, tetra-n-butylammonium formate, tetra-n-butylammonium benzoate, tetra-n-butylammonium-2-ethylhexanoate, tetra-n- consisting of butylammonium-p-ethylbenzoate, tetra-n-butylammonium propionate, and TBD-acetate (1,5,7-triazabicyclo[4.4.0]des-5-ene (TBD)) 15. A coating-forming composition according to any preceding claim which is at least one member selected from the group. 16. A coating-forming composition according to any preceding claim, having a viscosity in the range of 4.0 to 5.5 cStks at 25 [deg.]C. a) cooling the mixture of alkoxysilane (i) and acid hydrolysis catalyst (iv);
b) adding metal oxide (ii) and water (vi) to the cooled mixture of step (a);
c) adding a water-miscible solvent (iii) and a further acid hydrolysis catalyst (iv) to the mixture resulting from step (b);
d) subjecting the mixture resulting from step (c) to elevated temperature for a period measured to provide a curable coating-forming composition having a viscosity in the range of 3.0 to 7.0 cStks at 25°C. and e) optionally adding a condensation catalyst (vi) in any preceding step, during that step, or after that step . and a method for producing a coating-forming composition according to any one of 13-16 . a) cooling the mixture of metal oxide (ii) and acid hydrolysis catalyst (iv) to a temperature of -20°C to 15°C,
b) adding alkoxysilane (i) to the cooled mixture of step (b);
c) allowing the mixture obtained in step c) to come to room temperature (25° C.);
d) adding to the mixture obtained in step d) at least one water-miscible organic solvent (iii) and optionally a condensation catalyst (vi) and optionally one or more other optional components (vii) , obtaining a composition having a viscosity in the range of 3.0 to 7.0 cStks at 25°C. 19. The method of making a coating-forming composition according to claim 18 , wherein step (a) cools to a temperature of -10°C to 10°C. 19. The method of making a coating-forming composition according to claim 18 , wherein step (a) cools to a temperature of 0<0>C to 10<0>C. 19. The method of making a coating-forming composition according to claim 18 , wherein the metal oxide (ii) is selected from alumina-modified silica. 22. A method of making a coating-forming composition according to any of claims 17-21 , having a viscosity of 4.0 to 5.5 cStks at 25 [deg.]C. Alkoxysilanes (i) are trialkoxysilanes of Formula A wherein the subscript a is 0 or 1, the subscript b is 0 or 1, and a+b is 1, the trialkoxysilanes of Formula B, and 23. A method of making a coating-forming composition according to any of claims 17-22 , wherein the at least one member is selected from the group consisting of mixtures of trialkoxysilanes of formulas A and B. Alkoxysilane (i) is a dialkoxysilane of formula A with subscript a being 0 or 1, subscript b being 0, 1 or 2, and a+b being 2, subscripts a and b is at least one member selected from the group consisting of tetraalkoxysilanes of formula A wherein each of is 0, and mixtures thereof. Trialkoxysilanes of formula A are methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyl tripropoxysilane, n-propyltributoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, isooctyltriethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, ethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane, trifluoropropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3 -glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane, and the trialkoxysilane of Formula B is 1,2-bis(trimethoxy silyl)ethane, 1,2-bis(triethoxysilyl)ethane, bis(trimethoxysilylpropyl)disulfide, bis(triethoxysilylpropyl)disulfide, bis(trimethoxysilylpropyl)tetrasulfide, bis(triethoxysilylpropyl) ) is at least one member selected from the group consisting of tetrasulfide, bis(3-triethoxysilylpropyl)amine and bis(3-trimethoxysilylpropyl) amine . A method of making a coating-forming composition. Metal oxide (ii) is selected from the group consisting of silica, alumina, titania, ceria, tin oxide, zirconia, antimony oxide, indium oxide, iron oxide, titania doped with iron oxide and/or zirconia and rare earth oxides wherein the water-miscible solvent (iii) is selected from the group consisting of alcohols, glycols, glycol ethers and ketones. wherein the acid hydrolysis catalyst (iv) is sulfuric acid, hydrochloric acid, acetic acid, propanoic acid, 2-methylpropanoic acid, butanoic acid, pentanoic acid (valeric acid), hexanoic acid (caproic acid) , 2-ethylhexanoic acid, heptanoic acid (enanthic acid), hexanoic acid, octanoic acid (caprylic acid), oleic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, cyclohexylacetic acid, cyclohexenecarboxylic acid, benzoic acid, benzeneacetic acid, Propanedioic acid (malonic acid), butanedioic acid (succinic acid), hexanedioic acid (adipic acid), 2-butenedioic acid (maleic acid), lauric acid, stearic acid, myristic acid, palmitic acid, isoanoic acid, versa at least one or more members selected from the group consisting of tic acid, lauric acid, stearic acid, myristic acid, palmitic acid, isoanoic acid and amino acids, and wherein R ⁵ is hydrogen, 1 alkyl groups containing 8 carbon atoms from and aromatic groups containing 6 to 20 carbon atoms of the formula [(C ₄ H ₉ ) ₄ N] ⁺ [OC(O)- 18. The method of making a coating-forming composition according to claim 17 , also comprising at least one condensation catalyst (vi) selected from the group consisting of R ^{5 ]-} tetrabutylammonium carboxylates. The metal oxide (ii) is selected from alumina modified silica, wherein the water-miscible solvent (iii) is at least one member selected from the group consisting of alcohols, glycols, glycol ethers and ketones. , wherein the acid hydrolysis catalyst (iv) is sulfuric acid, hydrochloric acid, acetic acid, propanoic acid, 2-methylpropanoic acid, butanoic acid, pentanoic acid (valeric acid), hexanoic acid (caproic acid), 2-ethylhexanoic acid, Heptanoic acid (enanthic acid), hexanoic acid, octanoic acid (caprylic acid), oleic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, cyclohexylacetic acid, cyclohexenecarboxylic acid, benzoic acid, benzeneacetic acid, propanedioic acid (malonic acid) , butanedioic acid (succinic acid), hexanedioic acid (adipic acid), 2-butenedioic acid (maleic acid), lauric acid, stearic acid, myristic acid, palmitic acid, isoanoic acid, versatic acid, lauric acid, stearin at least one member selected from the group consisting of acids, myristic acid, palmitic acid, isoanoic acid and amino acids, and wherein ^R5 is hydrogen, alkyl containing 1 to 8 carbon atoms and aromatic groups ^containing from ₆ ^to ₂₀ ^carbon atoms _; 22. A process for the preparation of a coating-forming composition according to any of claims 18-21 , also comprising at least one condensation catalyst (vi) selected from the group consisting of rates. 18. The method of making a coating-forming composition according to claim 17 , wherein in step (a) the mixture is cooled to a temperature of -20°C to 15°C. 18. The method of claim 17 , wherein in step (a) the mixture comprises 10 to 50 weight percent of the total amount of acid hydrolysis catalyst (iv) and the balance of acid hydrolysis catalyst (iv) is added in step (c). A method of making the described coating-forming composition. 18. The method of making a coating-forming composition according to claim 17 , wherein in step (e) the mixture obtained from step (d) is aged at a temperature of 20[deg.]C to 100[deg.]C for 1 to 60 days. The coating-forming composition comprises at least one alkoxysilane selected from formula (A) and at least one alkoxysilane selected from formula (B), or hydrolysis and condensation products thereof, wherein R ¹ and ^R3 are as defined above. 32. A method of coating a metal surface to impart corrosion and/or wear resistance thereto, comprising applying a coating-forming composition according to any of claims 1 to 16 and 31 to applying to an uncoated or pre-coated surface of a metal where wear resistance is desired and curing the applied coating-forming composition to provide a corrosion and/or wear resistant coating thereon; How to include. 33. The coating-forming composition of claim 32 , wherein the coating-forming composition is applied to surfaces of anodized aluminum, bulk aluminum, magnesium, steel, copper, bronze or alloys thereof, metallized surfaces or metals having at least one protective layer. Method. 28. A method of coating a metal surface to impart corrosion and/or wear resistance thereto , comprising applying a coating-forming composition obtained by the process of any of claims 17-27 to the corrosion resistant to an uncoated or pre-coated surface of a metal where durability and/or wear resistance is desired, and curing the applied coating-forming composition to form a corrosion and/or wear resistant coating thereon. a method comprising bringing about 35. The coating-forming composition of claim 34 , wherein the coating-forming composition is applied to a surface of anodized aluminum, bulk aluminum, magnesium, steel, copper, bronze or alloys thereof, a metallized surface or a metal part having at least one protective layer. the method of. 32. A method of coating a metal surface to impart corrosion and/or wear resistance thereto, comprising applying a coating-forming composition according to any of claims 1 to 16 and 31 to applying to an uncoated or pre-coated surface of a metal where wear resistance is desired and curing the applied coating-forming composition to provide a corrosion and/or wear resistant coating thereon; A method of manufacturing a coated surface of a metal comprising: A metal substrate coated with a coating-forming composition according to any of claims 1-16 . 38. The coated metal of claim 37 , wherein the metal has a surface of anodized aluminum, bulk aluminum, magnesium, steel, copper, bronze, or alloys thereof, a metallized surface or a metal having at least one protective layer. Base material. The coating-forming composition comprises at least one alkoxysilane selected from formula (A) and at least one alkoxysilane selected from formula (B), or hydrolysis and condensation products thereof, wherein R ¹ and ^R3 are as defined above . applying a coating-forming composition to an uncoated or pre-coated surface of a metal for which corrosion and/or wear resistance is desired, and curing the applied coating-forming composition to provide corrosion resistance thereon; 40. A method of manufacturing a coated metal substrate according to any of claims 37-39 , comprising providing a toughness and/or wear resistant coating. 41. The coating-forming composition of claim 40 , wherein the coating-forming composition is applied to surfaces of anodized aluminum, bulk aluminum, magnesium, steel, copper, bronze or alloys thereof, metallized surfaces or metals having at least one protective layer. Method.