CH720102A2 - Method for producing an article comprising a colored abrasion-resistant coating, and article comprising such a coating - Google Patents

Abstract

The present invention relates to a method of producing an article comprising a substrate and a colored abrasion resistant coating present on at least a portion of a surface of the substrate, the method (10) comprising providing a substrate ( 1) comprising a metallic element and/or an alloy of a metallic element, and/or a polymer, providing a first compound (3) comprising a functional group R 1 selected from the group consisting of a C 1 alkyl to C 20 , a C 1 to C 20 cycloalkyl, a C 1 to C 10 aryl, an amide, an amine, a mercapto, a (meth)acrylate, and an epoxy, and optionally comprises at least one atom of halogen, and a second compound (4) comprising a crosslinkable functional group; hydrolyzing the first compound and the second compound; condensing the first and second hydrolyzed compounds, thereby obtaining a prepolymer; adding a colorant to the prepolymer; applying the prepolymer to at least a portion of a surface of the substrate; and inducing crosslinking of the crosslinkable functional group by exposing the prepolymer to one or more of a temperature of up to 250°C, UV radiation or IR radiation, thereby obtaining an article comprising a substrate and a colored abrasion-resistant coating covering at least a portion of a surface of the substrate; the colored abrasion-resistant coating being a crosslinked organic-inorganic hybrid coating comprising at least one R 1 functional group, and the crosslinked organic-inorganic hybrid coating being covalently bonded to the substrate.

Description

Technical field of the invention

The present invention relates to a method for producing an article comprising a substrate and a colored abrasion-resistant coating on at least part of the surface of the substrate. The present invention further relates to such articles.

Background of the invention

[0002] Protective coatings which improve the lifespan of the article or product are attracting more and more interest. For example, the lifespan of a product can be improved by placing a durable coating on surfaces likely to experience wear, such as abrasive wear, or be exposed to aggressive environments (humidity, temperature). .

[0003] Such protective coatings may be, depending on the application or use of the article they protect, abrasion resistant, corrosion inhibitors, water repellent, oil repellent, anti-fingerprint, UV resistant, or may have a certain hardness.

[0004] Furthermore, decorative coatings are today also used in a wide range of applications. In particular, protective coatings that are also decorative, or decorative coatings that also imply a certain degree of protection, are gaining interest, as they allow the manufacture of attractive products with improved performance and/or durability.

[0005] An example of a decorative coating is a colored coating. Colored coatings can be transparent, translucent or opaque. Colored coatings replace the use of colored parts, which can be expensive. For example, in the watch industry, black components can be used, such as carbon fiber, black ceramic, or laminated carbon components, but these components are usually expensive.

[0006] It is known to deposit a colored protective coating on the surface of a substrate, such as titanium or steel, by means of DLC and PVD processes. A disadvantage of these processes is the need to work in a controlled environment to avoid contamination, for example working in a glove box filled with an inert gas, or working at reduced pressure. Consequently, such processes are complex and expensive. Additionally, precursors used in such processes are often considered toxic and/or environmentally unfriendly.

[0007] In recent years, coatings obtained by means of a sol-gel process have become interesting. Sol-gel coatings are desirable for their environmental friendliness, high performance, compatibility with existing coating application technologies and for the simplicity of tailoring coating properties on demand.

[0008] In particular, organic-inorganic hybrid coatings, such as those known under the registered trademark Ormocer, obtained by means of a sol-gel process, have attracted interest. Such coatings have the potential to combine the intrinsic properties of inorganic materials with those of organic materials. Organic-inorganic hybrid materials provide characteristics that pure organic or inorganic material cannot provide. Generally, organic polymer materials possess good elasticity, toughness, formability, and have a rather low density, while inorganic materials are usually hard, rigid, and thermally stable. With organic-inorganic hybrid coatings, it is possible to modify and optimize the properties of the organic-inorganic hybrid coating by modifying the organic and inorganic structural patterns. Thanks to their inorganic network, organic-inorganic hybrid polymers are able to demonstrate high mechanical, chemical and thermal stability in aggressive environments.

[0009] The organic-inorganic hybrid coatings are characterized by a direct bond, that is to say a bond at the molecular scale, between the inorganic structural units and the organic structural units. Organic-inorganic hybrid coatings are thus a polymer with a three-dimensional inorganic network and a three-dimensional organic network interconnected with covalent bonds.

[0010] The sol-gel process is a process for producing solid materials from small molecules, and is considered a sustainable and non-toxic technique. The process involves the conversion of monomers into a colloidal solution (sol) which acts as a precursor for an integrated network (or gel) of either discrete particles or networked polymers (cross-linked polymers).

[0011] 'Characteristics of colored inorganic-organic hybrid materials', K. Wojtach, M. Laczka, et al., Journal of Non-Crystalline Solids 2007, volume 353, issues 18-21, pages 2099-2103, discloses coatings colored organic-inorganic hybrids applied to a glass substrate using a sol-gel process. The coatings are obtained from phenyltriethoxysilane (PhTES), 3-glycidoxypropyltrimethoxysilane (GPTMS), tri-sec-aluminum butoxide (TBA) and metal complex dyes, which are added to the polymer matrix. Colored organic-inorganic hybrid coatings exhibit good chemical resistance and color stability. The colored glass is still transparent.

[0012] Document EP 0 486 469 discloses an abrasion-resistant coating composition comprising an organoalkoxysilane and a hydrolyzable compound of a metal such as titanium or zirconium. The composition may further comprise a pigment or a mixture of pigments to form a durable, non-porous paint. The organic-inorganic hybrid polymers are obtained by means of a sol-gel process, and can be applied to the surface of a plastic substrate.

[0013] A disadvantage of the aforementioned organic-inorganic hybrid coatings is that several dyes are considered toxic, in particular dyes based on metal complexes. This generally limits the amount of dye that can be used, which can impact the uniformity and saturation of the coating, resulting in colored items considered of lower quality. Toxic chemicals also limit the application or end use of the resulting colored articles, as contact, for example with the environment or skin, may need to be avoided.

Summary of the invention

The present invention aims to overcome one or more of the above drawbacks. An object of the invention is to provide a method of producing an article comprising a substrate and a colored abrasion resistant coating, the method being carried out at moderate temperatures and not requiring long processing times. In other words, an object is to provide processes whose energy consumption is reduced compared to prior art processes. A further object is to provide a process which does not require the use of harsh or toxic components, thereby providing processes with a lower environmental impact and providing articles which can be used in a wider range of applications.

[0015] An additional object of the invention is to provide an article comprising a substrate comprising a colored coating resistant to abrasion, in particular coatings having excellent adhesion to the substrate. An additional objective is to provide an article comprising a substrate and a coating, the coating improving the lifespan and/or durability of the substrate. An additional objective is to provide an article in which the coating gives the substrate, in addition to a color, at least excellent abrasion resistance, protection against corrosion or excellent hardness.

[0016] According to a first aspect of the invention, there is disclosed a method for producing an article comprising a substrate and a colored abrasion-resistant coating present on at least part of a surface of the substrate as mentioned in the appended claims.

[0017] The method comprises providing a substrate. The substrate comprises a metallic element and/or an alloy of a metallic element, and/or a polymer. For example, the substrate may be a metal substrate, such as copper, an alloy, such as a copper alloy (e.g. brass), a polymer, such as methacrylate-acrylonitrile-butadiene-styrene (MABS) , or a composite comprising both a polymer and a metallic element or alloy thereof. For example, a composite may comprise a polymer matrix reinforced by metallic elements, such as metal fibers or wires.

[0018] The method further comprises providing a first compound according to formula (I) in which M is silicon or titanium, R<1> is a group comprising one or more functional groups selected from the group consisting of C1-C20 alkyl, C1-C20 cycloalkyl, C1-C10 aryl, amide, amine, mercapto, (meth) acrylate, and an epoxy, and R<2>, R<3>, R<4>, R<6>, R<7>, and R<8> are each independently of each other H, a C1 to C20 alkyl, a C1 to C10 aryl , a C1 to C20 alkenyl, a C1 to C20 alkylaryl, or a C1 to C20 arylalkyl.

[0019] The method further comprises providing a second compound according to formula (II) in which M is silicon or titanium, R<5> is a functional group capable of being crosslinked, and R<2>, R<3>, R<4>, R<6>, R<7>, and R<8> are each independently of each other H, a C1 to C20 alkyl, a C1 to C10 aryl , a C1 to C20 alkenyl, a C1 to C20 alkylaryl, or a C1 to C20 arylalkyl.

[0020] Optionally, R<1> comprises at least one halogen atom. Advantageously, the halogen atom is fluorine, chlorine, bromine, or iodine.

[0021] According to one embodiment, R<1> is a group comprising an epoxy functional group.

According to another embodiment, R<1> is a C1 to C20 alkyl, that is to say an alkyl having between 1 and 20 carbon atoms in its chain. Advantageously, when R<1> comprises a halogen atom, R<1> is a C1 to C20 alkyl having the formula -(CH2)x(CF2)yCF3, x being between 0 and z-1, y being z-x-1 , and z being the total number of carbon atoms, i.e. z is between 1 and 20. For example, when R<1> is a C8 alkyl, i.e. z is 8, it can have the formula -(CH2)2(CF2)5CF3(x being 2 and y being 5).

[0023] “Functional group capable of being crosslinked” is understood, in the context of the present disclosure, to mean a functional group which is capable of reacting with other functional groups. During the reaction, covalent bonds are formed, resulting in a cross-linked polymer. A cross-linked polymer can be considered as a polymer having a three-dimensional structure.

Advantageously, R<5> is a group which can be thermo-crosslinked and/or a group which can be photo-crosslinked. In other words, R<5> can be thermo-crosslinked, photo-crosslinked, or both.

[0025] By “group capable of being thermo-crosslinked”, in the context of the present disclosure, we mean that the crosslinking of R<5> is induced and/or takes place by thermal crosslinking, also called thermal hardening. Thermal curing is carried out by exposing the (thermo-)crosslinkable group and therefore, in the present disclosure, the prepolymer comprising such a crosslinkable group, to an elevated temperature, i.e. by heating the prepolymer .

[0026] By “group capable of being photo-crosslinked”, in the context of the present disclosure, we mean that the crosslinking of R<5> is induced and/or takes place by photochemical crosslinking, also called photochemical hardening. Photochemical curing is carried out by exposing the (photo-)crosslinkable group and therefore, in the present disclosure, the prepolymer comprising such a crosslinkable group, to radiation. Advantageously, the radiation comprises one or more of infrared (IR) radiation, ultraviolet (UV) radiation, or radiation with light having a wavelength in the visible light (VIS) wavelength range. .

Advantageously, R<5> is a functional group selected from the group consisting of an epoxy, a (meth)acrylate, an ester, a mercapto, a vinyl, and a (meth)acrylated urethane. By “(meth)acrylate” is meant, in the present disclosure, that the functional group can be an acrylate or a methacrylate.

Advantageously, R<2>, R<3>, R<4>, R<6>, R<7>, and R<8> are each independently of each other H or a C1 to C20 alkyl, preferably C1-C8 alkyl, more preferably C1-C6 alkyl, most preferably C1-C4 alkyl. In particular, R<2>, R<3>, R<4>, R<6>, R<7>, and R<8> are each independently a methyl (-CH3, that is to say a C1 alkyl), or ethyl (-C2H5, i.e. C2 alkyl).

The process further comprises the hydrolysis of the first compound and the second compound in the presence of water. Upon hydrolysis, the C1-C8 alkyl chain of any of R<2>, R<3>, R<4>, R<6>, R<7>, and R<8> is converted to a, or reacts with the formation of a, hydrogen atom, thereby forming hydroxyl groups. The hydrolysis reaction also produces alcohol molecules with the formula CxH2x+1OH, where x is the number of carbon atoms in the C1-C8 alkyl chain of R<2>, R<3>, R<4> , R<6>, R<7>, and R<8> (i.e. x is between 1 and 8).

The process further comprises the condensation of the first hydrolyzed compound and the second hydrolyzed compound. During condensation, water molecules are formed and removed. A prepolymer is obtained from the first hydrolyzed compound and the second hydrolyzed compound. The prepolymer includes R<1> and R<5> as functional groups. The prepolymer can be considered as a so-called “sol”.

[0031] The process further comprises the addition of a dye to the prepolymer. Advantageously, the dye dissolves or disperses at least partially in the prepolymer.

Advantageously, the dye comprises or essentially consists of one or more of a carbon black, copper (II) phthalocyanine, or a triphenylmethane-based dye.

Advantageously, the dye comprises or consists essentially of (for example, is) a particulate compound. In other words, the dye advantageously comprises or consists essentially of particles. Advantageously, the particles have an average diameter of 500 nm or less, preferably 250 nm or less, more preferably 100 nm or less, such as 50 nm or less. Advantageously, the particles have an average diameter between 1 nm and 500 nm, such as between 2 nm and 250 nm, preferably between 5 nm and 100 nm, more preferably between 10 nm and 50 nm, for example 25 nm.

Advantageously, the dye is added so that the prepolymer comprising the dye comprises between 0.1% and 50% by weight of the dye, preferably between 0.5% and 30% by weight, more preferably between 1% and 25% by weight, based on the total weight of the prepolymer comprising the colorant.

The prepolymer is applied to at least part of a surface of the substrate. Application may be accomplished by methods known in the art, for example by casting or dipping the substrate into the prepolymer, spraying or electrospraying the prepolymer onto the substrate, bar coating, or roll-to-roll coating.

Advantageously, the substrate is pretreated before applying the prepolymer to at least part of it (called pretreatment). Advantageously, at least the part of the surface of the substrate on which the prepolymer is to be applied is pretreated. Advantageously, the substrate is pretreated by deposition of silicon oxide.

The method further comprises crosslinking the prepolymer applied to at least part of the surface of the substrate. Advantageously, the prepolymer is crosslinked by means of crosslinking the functional group R<5> which can be crosslinked.

[0038] When R<5> is a functional group capable of being thermo-crosslinked, the crosslinking is induced and/or carried out advantageously by exposing the prepolymer to a temperature of up to 250° C., advantageously a temperature between 25°C and 250°C, preferably between 30°C and 200°C, more preferably between 40°C and 150°C, such as between 50°C and 100°C.

When R<5> is a functional group capable of being photo-crosslinked, the crosslinking is induced and/or carried out advantageously by exposing the prepolymer to radiation. Advantageously, the radiation is IR radiation or UV radiation, or a combination thereof.

[0040] When R<5> is a functional group which can be thermo-crosslinked and which can be photo-crosslinked, the crosslinking is induced and/or carried out advantageously by exposing the prepolymer to a temperature of up to 250° C. and to radiation.

[0041] Upon crosslinking the prepolymer, an article comprising the substrate and a colored abrasion-resistant coating covering at least part of a surface of the substrate is obtained. The colored abrasion-resistant coating comprising at least one functional group R<1> (called “gel”). The colored abrasion resistant coating is a cross-linked organic-inorganic hybrid coating. The cross-linked organic-inorganic hybrid coating is covalently bonded to the metal element or alloy thereof of the substrate by means of oxygen-M bonds, M being as described above.

[0042] According to a second aspect of the invention, there is disclosed an article comprising a substrate and a colored abrasion-resistant coating present on at least part of a surface of the substrate as mentioned in the appended claims.

The substrate is as described above, that is to say that the substrate comprises a metallic element and/or an alloy of a metallic element, and/or a polymer.

The colored abrasion-resistant coating is a crosslinked organic-inorganic hybrid coating comprising at least one functional group R<1>. Advantageously, R <1> comprises one or more functional groups selected from the group consisting of a C1 to C20 alkyl, a C1 to C20 cycloalkyl, a C1 to C10 aryl, an amide, an amine, an ether, a mercapto (i.e. i.e. a thiol), a (meth)acrylate, and an epoxy.

[0045] Optionally, R<1> comprises at least one halogen atom. Advantageously, the halogen atom is fluorine, chlorine, bromine, or iodine. When R <1> comprises two or more halogen atoms, they can be the same or different, that is to say a combination of two or more of a fluorine, a chlorine, a bromine, and an iodine. The abrasion resistant coating further includes silicon and/or titanium. The cross-linked organic-inorganic hybrid coating is covalently bonded to the substrate using oxygen-silicon bonds or oxygen-titanium bonds, respectively.

According to one embodiment, R<1> is a group comprising an epoxy functional group.

According to another embodiment, R<1> is a C1 to C20 alkyl, that is to say an alkyl having between 1 and 20 carbon atoms in its chain. Advantageously, when R<1> comprises a halogen atom, R<1> is a C1 to C20 alkyl having the formula -(CH2)x(CF2)yCF3, x being between 0 and z-1, y being z-x-1 , and z being the total number of carbon atoms, i.e. z is between 1 and 20. For example, when R<1> is a C8 alkyl, i.e. z is 8, it can have the formula -(CH2)2(CF2)5CF3(x being 2 and y being 5).

[0048] The crosslinked organic-inorganic hybrid coating comprises a dye. The dye is advantageously as described above.

The colored abrasion-resistant coating advantageously has an abrasion resistance of at most 15%, preferably at most 10%, for example at most 5%. Advantageously, abrasion resistance is measured in accordance with ASTM D1044 (also called Taber abrasion). Advantageously, the abrasion resistance is measured in accordance with ASTM D1044 by applying a load of 500 g. Advantageously, the abrasion resistance is expressed as (i.e. the percentage abrasion resistance value represents) the runout which is measured after 100 revolutions.

Advantageously, when the substrate comprises a metallic element and/or an alloy of a metallic element, the colored abrasion-resistant coating present on at least part of a surface of the substrate further inhibits corrosion.

[0051] In the context of the present disclosure, “a corrosion inhibitor coating” means that the presence of the coating on a substrate reduces, and advantageously prevents, the formation of corrosion on the areas of the surface of the substrate comprising such coating.

[0052] Advantageously, the article of the present disclosure comprises components of watches, clocks and jewelry. Advantageously, the article is a (colored) watch component.

[0053] According to a third aspect of the invention, a use of a method of the first aspect as mentioned in the appended claims is disclosed. Advantageously, the method is used to obtain a (colored) watch article.

[0054] The advantages of the methods of the present disclosure include, but are not limited to, the ability to apply a colored coating to a wide range of substrates, where the colored coating may have multiple property characteristics, such as, without s limited to this, resistance to abrasion, excellent adhesion to the substrate and resistance to corrosion. Another advantage is that the methods of the present disclosure make it possible to provide coatings of different colors, as well as opaque, transparent or translucent coatings. The processes allow you to vary the saturation of the color. Yet another advantage is that the methods are particularly suitable for homogeneously applying a colored coating to substrates with complex geometry. The thickness of the coating can be well controlled so that the thickness remains within tolerances.

Brief description of the figures

[0055] Aspects of the invention will now be described in more detail with reference to the accompanying drawings, in which identical reference numbers illustrate identical elements and in which: - Figure 1 schematically represents the steps of a process according to the present disclosure, – Figure 2 presents an article obtained by a method according to the present disclosure, – Figure 3 presents an article obtained by another method according to the present disclosure.

Detailed description of the invention

[0056] Figure 1 schematically represents the steps of a method according to the present disclosure. The method 10 comprises the step of providing a substrate 1.

Advantageously, the substrate comprises or consists essentially of a metallic element and/or an alloy of a metallic element. Non-limiting examples of the metallic element include iron, copper, aluminum, zinc, silver, gold, tin, manganese, and nickel. The substrate may include two or more metallic elements and/or alloys thereof.

Advantageously, the substrate comprises or consists essentially of copper or a copper alloy, such as brass or bronze. Alternatively and advantageously, the substrate comprises iron or an iron alloy, such as a steel, for example a stainless steel or a carbon steel.

[0059] “Consisting essentially of”, in the present invention, means that the quantity of impurities or other components present in the substrate is advantageously less than 1% by weight, preferably less than 0.5 % by weight, more preferably less than 0.1 % by weight, as less than the detection limit of analytical techniques used to determine composition, such as X-ray photoelectron spectroscopy (XPS).

[0060] Alternatively or in addition, and advantageously, the substrate comprises a polymer or a combination of polymers, including copolymers. Non-limiting examples of polymers and copolymers include polyethylene, polypropylene, polyester (e.g., PBT or PET), polyamide (e.g., PA6, PA6-6), polyimide, polyamideimide, polystyrene , a polytetrafluoroethylene (PTFE), a polyurethane, a polymethyl methacrylate, a polycarbonate, and a methacrylateacrylonitrile-butadiene-styrene (MABS).

[0061] Optionally, the substrate may include other additives. Such additives may be additives known in the art, such as fillers or flame retardants.

The method further comprises providing a first compound 3 according to formula (1), formula (I) being as described above.

[0063] Advantageously, R <1> comprises or consists of one or more functional groups selected from the group consisting of a C1 to C20 alkyl, a C1 to C20 cycloalkyl, a C1 to C10 aryl, an amide, an amine, an ether , a mercapto (i.e. a thiol), a (meth)acrylate, and an epoxy.

[0064] Optionally, R<1> comprises at least one halogen atom. Advantageously, the halogen atom is fluorine, chlorine, bromine, or iodine. When R <1> comprises two or more halogen atoms, they can be the same or different, that is to say a combination of two or more of a fluorine, a chlorine, a bromine, and an iodine.

[0065] Advantageously, a “C1 to C20 alkyl” comprises alkyl functional groups comprising between 1 and 20 carbon atoms in the chain. Advantageously, the C1 to C20 alkyl is a C1 to C12 alkyl, preferably a C1 to C10 alkyl, such as a C1 to C8 alkyl, a C1 to C6 alkyl, or a C1 to C4 alkyl.

[0066] Advantageously, a “C1 to C20 cycloalkyl” comprises cycloalkyl functional groups comprising a total of between 1 and 20 carbon atoms in the chain.

[0067] Advantageously, a “C1 to C10 aryl” comprises aryl functional groups comprising between 1 and 10 carbon atoms in the chain. For example, R<1> may comprise a phenyl functional group, or may be (C1-C20 alkyl)phenyl.

Advantageously, when R<1> comprises an amide functional group, R<1>a for formula -(CH2)aC(O)NH2, in which a is between 0 and 20, preferably between 1 and 10, as between 2 and 8, between 2 and 6, or between 2 and 4, such as 2, 3 or 4. Optionally, one or more hydrogen atoms of one or more methyl groups (i.e. CH2 groups) are replaced by a halogen atom. Advantageously, the halogen atom is a fluorine.

Advantageously, when R<1>comprises an amino functional group, R<1>a for formula -(CH2)pNH2, in which p is between 1 and 20, preferably between 1 and 10, such as between 1 and 8 , between 1 and 6, or between 1 and 4, such as 1, 2, 3 or 4. Optionally, one or more hydrogen atoms of one or more methyl groups (i.e. CH2 groups ) are replaced by a halogen atom. Advantageously, the halogen atom is a fluorine.

Advantageously, when R <1> comprises a mercapto (thiol) functional group, R <1> has the formula -(CH2)uSH, in which u is between 1 and 20, preferably between 1 and 10, as between 1 and 8, between 1 and 6, or between 1 and 4, such as 1, 2, 3 or 4. Optionally, one or more hydrogen atoms of one or more methyl groups (i.e. the CH2) groups are replaced by a halogen atom. Advantageously, the halogen atom is a fluorine.

Advantageously, when R1 comprises a (meth)acrylate functional group, R<1>a has the formula -(CH2)bOC(O)CXCH2, in which X is H when R<1>is an acrylate functional group and CH3 when R<1> is a methacrylate functional group, and b is between 1 and 20, preferably between 2 and 12, for example between 3 and 10, or between 4 and 8. Optionally, one or more hydrogen atoms of one or more methyl groups (i.e. CH2 groups) are replaced by a halogen atom. Advantageously, the halogen atom is a fluorine.

Advantageously, R <1> comprises or consists essentially of an epoxy functional group (that is to say an oxirane functional group). For example, R<1> may be an alpha-epoxy or a 1,2-epoxy, which comprises a three-membered ring structure.

[0073] Alternatively, R<1> may comprise or consist essentially of a C1 to C20 alkyl according to formula (III) -(CH2)x(CF2)yCF3(III) in which x is between 0 and z-1, y is z-1-x, and z is the number of carbon atoms in the chain, and is between 0 and 20.

[0074] For example, R<1> can be -(CH2)2(CF2)5CF3, that is to say that z is 8, x is 2 and y is 5. For example, R<1> can be -(CH2)5CF3, that is, z is 6, x is 5 and y is 0.

[0075] R<1> may be a C1 to C20 perfluoroalkyl, that is to say an alkyl in which all the hydrogen atoms are replaced by fluorine atoms, in accordance with -(CF2)yCF3, i.e. that is to say in which in formula (III) x is 0, y is z-1, and z is between 1 and 20. For example, R<1> can be a C8 perfluoroalkyl, i.e. -say -(CF2)7CF3(z = 8, x = 0 and y = 7 in formula (III)), a C6 perfluoroalkyl, i.e. -(CF2)5CF3(z = 6, x = 0 and y = 5 in formula (III)), or a C4 perfluoroalkyl, i.e. - (CF2)3CF3(z = 4, x = 0 and y = 3 in formula (III) ).

[0076] R<1> may be a functional group conferring water-repellent and oil-repellent properties to the abrasion-resistant colored coating. Advantageously, when R<1> is a water- and oil-repellent functional group, R<1> also provides corrosion protection or corrosion inhibition to the substrate. However, the inventors unexpectedly discovered that R<1> does not need to be water and oil repellent to provide corrosion protection or corrosion inhibition to the substrate.

Advantageously, when R<1> is a water-repellent and oil-repellent functional group, R<1> comprises at least one halogen atom. Advantageously, the halogen atom is fluorine, chlorine, bromine, or iodine. When R <1> comprises two or more halogen atoms, they can be the same or different, that is to say a combination of two or more of a fluorine, a chlorine, a bromine, and an iodine.

The method further comprises providing a second compound 4 according to formula (II), formula (II) being as described above.

Advantageously, the first compound and the second compound are hydrolyzed as explained above. Advantageously, the first hydrolyzed compound and the second hydrolyzed compound are condensed 6 as explained above, to thus obtain a prepolymer.

[0080] The process further comprises the addition of a dye 7 to the prepolymer. Advantageously, the dye is a pigment or a dye. Advantageously, the dye is as described above. Advantageously, the dye is added to the prepolymer in an amount as described above.

Advantageously, the dye dissolves at least partially in the prepolymer. Alternatively, the dye is at least partially dispersed in the prepolymer, i.e. a dispersion comprising the prepolymer and the dye is obtained.

[0082] Optionally, other components or substances can be added to the prepolymer. For example, a surfactant can be added to the prepolymer. Advantageously, when a surfactant is added, it is added in an amount between 0.5% and 30% by weight, relative to the total weight of the prepolymer.

[0083] Advantageously, the prepolymer comprising the dye is applied 8 to at least part of a surface of the substrate as explained above. Various application methods known in the art may be used. A preferred method includes immersing the substrate in the prepolymer, thereby contacting (that part of) the surface of the substrate to which the prepolymer is to be applied with the prepolymer. The substrate may be immersed in the prepolymer by means of dipping the substrate into the prepolymer.

[0084] The method further comprises crosslinking 9 of the prepolymer, thus obtaining a colored coating resistant to abrasion on the substrate. Crosslinking 9 is advantageously carried out as described above.

[0085] Optionally, the substrate can be pretreated 2 before applying 8 the prepolymer to at least part of a surface of the substrate. Advantageously, at least (the part of) the surface of the substrate on which the prepolymer will be applied is pretreated.

[0086] Advantageously, the pretreatment comprises cleaning at least (part of) the surface of the substrate (so-called precleaning). Precleaning can be accomplished by methods known in the art. Non-limiting examples include grinding and polishing, chemical cleaning, ultrasonic cleaning, sandblasting, atmospheric pressure or reduced pressure plasma treatment, or corona (air plasma) treatment, or alkaline. Advantageously, an alkaline treatment, for example an alkaline pre-cleaning, comprises washing the surface with a solution having a pH between 7 and 14. For example, the alkaline treatment may comprise washing the surface with alkaline water, such as alkaline water having a pH between 8 and 9. The inventors have discovered that a pretreatment comprising an alkaline treatment makes it possible to improve the adhesion of the colored coating to the substrate.

[0087] Alternatively or in addition, and advantageously, the pretreatment comprises a deposition of silicon oxide on at least the part of the surface of the substrate on which the prepolymer will be applied. Silicon oxide may be deposited using methods known in the art, such as by combustion chemical vapor deposition.

[0088] The inventors have discovered that the deposition of silicon oxide on the surface of the substrate before the application of the prepolymer makes it possible to improve the adhesion of the colored coating on the substrate. Such pretreatment also makes it possible to obtain more uniform coverage of the surface of the substrate to which the prepolymer is applied. This is particularly an advantage when the substrate has a more complex geometric shape and/or a textured (e.g. patterned) surface, compared to traditional processes in which the deposition or formation of a coating is rather non-homogeneous for more complex substrates.

Advantageously, the colored abrasion-resistant coating is an organic-inorganic hybrid coating. Advantageously, the colored abrasion-resistant coating is a crosslinked organic-inorganic hybrid coating. Advantageously, the colored abrasion-resistant coating is at least partially covalently bonded to the surface of the substrate. Advantageously, the colored abrasion-resistant coating is covalently bonded to the substrate through bonds comprising oxygen.

Advantageously, the crosslinked organic-inorganic hybrid coating comprises one or more of silicon, titanium, zirconium, aluminum, iron, or boron, preferably silicon and/or titanium.

[0091] When the substrate comprises a metallic element, the colored abrasion-resistant coating is advantageously at least partially covalently bonded to the metallic element. When the substrate comprises an alloy of a metallic element, the colored abrasion-resistant coating is advantageously at least partially bonded to the metallic element included in the alloy. Advantageously, the colored abrasion resistant coating is covalently bonded to the metallic element through bonds including oxygen, such as oxygen atoms of the coating covalently bonded to the metallic element. Advantageously, when the crosslinked organic-inorganic hybrid coating comprises silicon and/or titanium, the coating is at least partially covalently linked to the metallic element of the substrate by silicon-oxygen-metallic element and/or titanium-oxygen bonds. -metal element, respectively.

[0092] When the substrate comprises a polymer, the colored abrasion-resistant coating is advantageously at least partially covalently bonded to the polymer. Advantageously, the colored abrasion resistant coating is covalently bonded to the polymer of the substrate through bonds including oxygen, such as oxygen atoms of the coating covalently bonded to the polymer.

Advantageously, the crosslinked organic-inorganic hybrid coating further comprises carbon-silicon bonds.

[0094] The colored abrasion-resistant coating can be transparent, translucent (that is to say semi-transparent) or opaque. Advantageously, the colored coating may have a color saturation, that is to say a color depth, which is variable depending on the final application of the article.

Advantageously, the saturation and the degree of transparency (varying between transparent and opaque) can be modified by varying the type and/or quantity of dye added to the prepolymer and/or the thickness of the coating.

Advantageously, the coating has a thickness between 1 µm and 20 µm, preferably between 1.2 µm and 10 µm, as well as between 1.5 µm and 5 µm. As will be understood, the optimum coating thickness depends, among other things, on the substrate, particularly its composition and shape, the required saturation and transparency of the coating, and the intended use of the article. .

[0097] Abrasion resistance can be measured by methods known in the art. Advantageously, and in particular, the abrasion resistance is measured in accordance with ASTM D1044 (called Taber abrasion). Abrasion resistance in accordance with ASTM D1044 is tested using abrasive wheels, such as rubber wheels with embedded alumina particles. A load weighing 250 g, 500 g or 1000 g is then placed on top of the abrasive wheel(s). Advantageously, in the context of the present disclosure, the abrasion resistance is measured in accordance with ASTM D1044 by applying a load of 500 g.

[0098] According to ASTM D1044, the abrasion resistance is expressed by (i.e. the percentage abrasion resistance value represents) the runout which is measured after a predetermined number of revolutions , for example, but not limited to, 20, 25, 50, 75, 100, 150, 200 or 250 revolutions. As will be understood, the load applied and the number of revolutions depend on the substrate that is to be tested and, in particular, the intended use of the substrate. Low haze values, i.e. less than 10%, are, for the purposes of the present disclosure, considered to be an indication of high abrasion resistance.

[0099] Advantageously, the haze is measured by transmission or reflection of light. As will be understood, whether the light is transmitted or reflected depends on the substrate to be analyzed. For example, haze on an abraded transparent substrate will be measured by the transmission of light (transmission mode), while an opaque substrate will be measured by the reflection of light (reflection mode).

[0100] Advantageously, the article of the present disclosure has an abrasion resistance of at most 10%, such as at most 7.5%, or at most 5%, measured in accordance with ASTM D1044 after 100 revolutions and with an applied load of 500 g.

[0101] Depending on the functional group R<1>, the coating can give the substrate additional characteristics. For example, when R<1> is a water and oil repellent functional group, the coating may make the substrate easy to clean and/or may provide corrosion inhibition or corrosion protection to the substrate, i.e. mean providing an item that is easy to clean and/or resistant to corrosion.

Examples

Example 1

[0102] Brass (copper alloy) substrates were pretreated by grinding, polishing and alkaline treatment. A first substrate was a disk having a flat, smooth surface without texture to which the coating was to be applied. A second substrate was one having multiple sides and edges, as well as textured areas at the edges. In other words, the first substrate can be considered as a substrate having a simple geometry, while the second substrate has a more complex geometry.

[0103] A prepolymer was prepared according to Table 1. 15% by weight of carbon black, as a dye, was dispersed in the prepolymer. The carbon black was added in the form of particles having an average size of 25 nm. Dispersion of carbon black particles was carried out using a high speed dissolver, operated at 5000 rpm for 15 minutes, followed by ultrasonic treatment for 15 minutes. A surfactant comprising a copolymer containing groups having affinity for pigments was also added to the prepolymer. A soluble black dye was also added. Soluble black dye was added to obtain an opaque colored coating.

[0104] The prepolymer comprising carbon black was applied to the pretreated brass substrates (that is to say the first and second substrates) by immersing the brass substrates in the prepolymer. Different amounts of prepolymer were applied to both the first substrate and the second substrate to obtain coatings having different thicknesses. After removing the brass substrates from the prepolymer, the prepolymer on the brass was cross-linked by subjecting the substrate to thermal curing at 160 °C for 2 hours.

[0105] A first coating had a thickness of 3.0 to 4.0 μm and was opaque and slightly shiny. A second coating was 5.0 to 6.0 µm thick and was also slightly glossy and opaque. Visual inspection showed a black color having homogeneous saturation. Very uniform coverage of the surfaces of the first substrate (disc) was obtained for both coating thicknesses. However, a less uniform result was obtained on the second substrate, where at the textured edges the coating was less uniform than on the larger flat surfaces of the substrate (Figure 2). This effect was observed for both coating thicknesses.

Table 1: composition of the coating

[0106] 25% 15% 6% 3%

[0107] Abrasion was tested in accordance with ASTM D1044. A load of 500 g was applied to the abrasive wheel and 100 revolutions were made. The runout was measured after 100 revolutions. Haze was measured in reflection mode, as brass is not transparent. Both coated substrates exhibited excellent abrasion resistance (haze value) of only 1.5% to 2%, regardless of coating thickness.

[0108] The anti-corrosion properties of the articles were also tested. The coated substrates were exposed to a relative humidity of 92°C to 50°C for 7 days. Subsequent visual inspection showed no change in the black brass items in terms of color changes, and no stains were observed on the surface.

[0109] The adhesion of the coatings was tested on the black articles which had been exposed to a relative humidity of 92° C. to 50° C. for 7 days. Adhesion has been tested in accordance with ASTM 3359-95A. Adhesion was very good and no delamination at the edges was noted.

Example 2

The second brass substrate of Example 1 (complex geometry) was pretreated according to Example 1, followed by a deposition of SiO2. The SiO2-brass samples were then coated with the coatings and by means of the method as in Example 1. The coatings were again very homogeneous in terms of saturation and were opaque. As shown in Figure 3, the surface coverage of the second substrate was now seamless and uniform across the entire substrate, including at the textured edges. This demonstrates the interest of depositing SiO2 as a pretreatment on substrates having a more complex geometry and/or a textured surface.

[0111] The adhesion of the coatings was tested again after exposing the articles to a relative humidity of 92° C. to 50° C. for 7 days. Adhesion has been tested in accordance with ASTM 3359-95A. Adhesion was very good and no delamination at the edges was noted.

Example 3

[0112] Plates of transparent polymer made of methyl methacrylate-acrylonitrile-butadiene-styrene (MABS polymer) were coated by immersing the plates in 5 different prepolymers at a speed of 100 mm/min. 1.5 wt% Orasol Blue for 30% coating solids content was added as a blue colorant to the prepolymer. One sample was cured at 95°C for 1 hour (sample 1), 4 samples (samples 2 to 5) were cured using UV radiation for 10 seconds.

[0113] The adhesion of the samples was tested in accordance with ASTM 3359-95A, and 100% adhesion was observed (no delamination observed).

[0114] The colored coatings on the samples were clear, transparent and shiny for samples 1 and 2, partially matt and cloudy on sample 3, and slightly matt for samples 4 and 5.

[0115] Abrasion resistance was tested in accordance with ASTM D1044. A load of 500 g was applied to the abrasive wheel and 100 revolutions were made. The runout was measured after 100 revolutions in transmission mode. All samples had an abrasion resistance between 1.5% and 5%.

Nomenclature

[0116] 1 supply of a substrate 2 optional pretreatment of the substrate 3 supply of a first compound 4 supply of a second compound 5 hydrolysis 6 condensation 7 add a dye 8 apply to the substrate 9 crosslink 10 process

Claims (15)

1. Method (10) for producing an article comprising a substrate and a colored abrasion-resistant coating present on at least part of a surface of the substrate, the method comprising: – the provision of a substrate (1), in which the substrate comprises a metallic element and/or an alloy of a metallic element, and/or a polymer, – the supply of a first compound according to formula (I) (3) and a second compound according to formula (II) (4) in which M is silicon or titanium, R<1> is a group comprising one or more functional groups selected from the group consisting of C1-C20 alkyl, C1-C20 cycloalkyl, C1-C10 aryl, amide, amine, mercapto, (meth) acrylate, and an epoxy, and optionally comprises at least one halogen atom, R<5> is a functional group that can be crosslinked, R<2>, R<3>, R<4>, R<6>, R<7>, and R<8> are each independently of each other H, a C1 to C20 alkyl, a C1 to C10 aryl , a C1 to C20 alkenyl, a C1 to C20 alkylaryl, or a C1 to C20 arylalkyl, – the hydrolysis (5) of the first compound and the second compound in the presence of water, – the condensation (6) of the first hydrolyzed compound and the second hydrolyzed compound, thus obtaining a prepolymer comprising R<1> and R<5> as functional groups, – the addition (7) of a dye to the prepolymer, – the application (8) of the prepolymer comprising the dye on at least part of a surface of the substrate, and – induction of crosslinking (9) of the functional group R<5> capable of being crosslinked by exposing the prepolymer comprising the dye to one or more of a temperature of up to 250 °C, UV radiation or radiation IR, to thus obtain an article comprising a substrate and a colored abrasion-resistant coating covering at least part of a surface of the substrate, characterized in that the colored abrasion-resistant coating is a crosslinked organic-inorganic hybrid coating comprising at least one functional group R<1>, and in that the crosslinked organic-inorganic hybrid coating is covalently bonded to the substrate. 2. A method (10) for producing an article according to claim 1, wherein the dye is at least partially dissolved or dispersed in the prepolymer. 3. A method (10) of producing an article according to any one of the preceding claims, wherein the dye comprises one or more of carbon black, copper(II) phthalocyanine, or a triphenylmethane dye . 4. Method (10) for producing an article according to any one of the preceding claims, in which the dye is a particulate compound, in which the particles have an average diameter of 250 nm or less, preferably 100 nm or less. 5. A method (10) of producing an article according to any one of the preceding claims, wherein the prepolymer comprising the colorant comprises between 0.5% and 30% by weight of the colorant, based on the total weight of the prepolymer including the dye. 6. A method (10) for producing an article according to any one of the preceding claims, wherein R<1> is a group comprising an epoxy functional group. 7. Method (10) for producing an article according to any one of claims 1 to 5, in which R<1> is -(CH2)x(CF2)yCF3, in which x is between 0 and z-1 , y is z-x-1, and z is the number of carbon atoms and is between 1 and 20. 8. Method (10) for producing an article according to any one of the preceding claims, in which R<5> is a functional group selected from the group consisting of an epoxy, a (meth)acrylate, an ester, a mercapto, a vinyl, and a (meth)acrylated urethane. 9. Method (10) for producing an article according to any one of the preceding claims, in which R<2>, R<3>, R<4>, R<6>, R<7>, and R <8> are each independently of one another a C1 to C8 alkyl, preferably a C1 to C4 alkyl. 10. Method (10) for producing an article according to any one of the preceding claims, in which the substrate is pretreated (2) by means of a deposition of silicon oxide before applying (8) the prepolymer comprising the dye on at least part of a surface of the substrate. 11. Article comprising a substrate and a colored abrasion-resistant coating present on at least part of a surface of the substrate, in which the substrate comprises a metallic element and/or an alloy of a metallic element, and/or a polymer, wherein the colored abrasion-resistant coating is a crosslinked organic-inorganic hybrid coating comprising at least one functional group R<1>, wherein R<1> comprises one or more functional groups selected from the group consisting of a C1 to C20 alkyl, a C1 to C20 cycloalkyl, a C1 to C10 aryl, an amide, an amine, a mercapto, a (meth)acrylate and an epoxy, optionally comprising at least one halogen atom, characterized in that the crosslinked organic-inorganic hybrid coating comprises a colorant, in that the crosslinked organic-inorganic hybrid coating comprises silicon and/or titanium, in that the crosslinked organic-inorganic hybrid coating is covalently bonded to the substrate by means of oxygen-silicon or oxygen-titanium bonds, respectively, and in that the article has an abrasion resistance of not more than 10%, wherein the abrasion resistance is measured in accordance with ASTM D1044 and expressed by the veil after 100 revolutions at a load of 500 grams. 12. Article according to claim 11, wherein R<1> is a group comprising an epoxy functional group. 13. Article according to any one of claims 11 to 12, in which the substrate comprises a metallic element and/or an alloy of a metallic element, and in which the colored abrasion-resistant coating present on at least one part of a surface of the substrate inhibits corrosion. 14. Article according to any one of claims 11 to 13, wherein the article is a colored watch component. 15. Use of a process (10) according to any one of claims 1 to 10, to obtain a colored watch component.