Substrate comprising an abrasion-resistant diffusion barrier layer system

ES 2 276 702 T3

DESCRIPTION

Substrate equipped with an insulating barrier blocking system against diffusion, resistant to abrasive wear.

The present invention relates to a plastic material substrate provided with an insulating barrier blocking system, against diffusion resistant to abrasive wear, in which the coating system comprises a base layer, as well as a process for the manufacture of a substrate equipped with an insulating barrier blocking system, resistant to abrasion wear.

The coating of substrates with layers presenting special physical characteristics, such as high breaking values, superior resistance to abrasion wear, protection against the diffusion of substances, eg gases from the atmosphere or from water, is a great problem for substrates, which cannot be subjected to thermal stresses, since a hermetic seal without thermal compaction of purely organic layers is extremely difficult to achieve. Even with layers subjected to a sputtering treatment, the frequency of imperfections and the pin-buttonhole frequency is so great that it is not possible to speak of having a tight seal. In many cases such layers come to be considered sufficient, although they do not achieve a hermetic seal, they do nevertheless achieve a sufficiently firm surface.

On the other hand, coatings that receive wet chemical treatments, in which a solvent phase is applied, as a general rule to very open structures (polymers with a high free volume) where, in the case of systems containing particles, there must be clamping , which occur by the diffusion of gases and by the exchange of the transport of substances. For this reason it is also not possible to achieve a closure in the proper conditions with such systems, without having carried out a compression at high temperatures.

Even organic-inorganic composite systems are not in a position to sufficiently isolate without layering additional inorganic elements by the sparking process. The resistance to abrasive wear of such layers is certainly much higher in relation to typical plastics, such as polycarbonate (PC) and polymethyl methacrylate (PMMA, although for some applications they are not entirely suitable, eg for glazing). ).

Thin layers below 1 pm can generally be processed by gas phase separation processes, but also by the Sol-Gel process. In gas phase separation processes, there is also the possibility of producing purely inorganic layers. The purely inorganic layers, if they can be made free of pores, are also hermetically sealed even when they are presented in very thin layers, that is, substances such as gases or water cannot diffuse passing through them. This depends on the density of its lattice structure, which does not present any free volume, as in the case of organic polymers. On the other hand, they do not have sufficient flexibility to guarantee the passage of gaseous molecules through them at all.

Inorganic Sol-Gel materials have, after the separation process, a relatively low theoretical density, that is to say they do not provide a dense packing, since through the effect of change the sol particles as well as the sol molecules will prevent a high packing density. The switching effects take place due to dipole switching effects and / or hydrogen bonds or chemical bonds that prevent relaxation from taking place at low temperatures. The typical packing densities of such layers are between 5 and 25% of the theoretical density.

While by applying such layers of ceramic and glass-like materials by applying high temperatures, there is the possibility of conferring a subsequent compaction, this is not possible when the contribution is made on polymeric substrates. Typical temperatures for the consolidation of inorganic systems are between 450 and 1000 ° C, such processes not suitable for this reason for polymers. On the other hand, with the above-mentioned systems, relatively thin layers of polymeric substrates are certainly achieved, although extremely low mechanical strength and minimal scratch resistance result. This creates a problem especially for optics as regards the use of transparent layers, since very thin layer thicknesses are often required in this field.

WO 98/45502 relates to the process for providing a metallic surface with a glass-like layer. The formulation for the coating used in this case is obtained by hydrolysis and polycondensation of one or more silanes in the presence of SiO particles.₂ nanoscalars and / or at least a combination of the group of oxides and hydroxides or of alkali and alkaline earth metals. The coating composition is applied to the metal surface and the resulting coating is thermally solidified, giving rise to a glass-like layer. Everything seems to indicate that other glass-like layers can be applied to this layer, for which it is necessary to refer to the example relating to such layers of document WO 95/13249.

Document WO 95/13249 refers to the production on substrates of functional layers of the vitreous type, preferably colored or stained in the colloidal phase. The composition of the coating comprises a composition that is obtained by hydrolysis and polycondensation of one or more hydrolyzable silanes. To do this, a functional support is mixed and the composition mixed with the functional agent is applied to the substrate and solidifies.

ES 2 276 702 T3 thermally transforming into a glass-like layer. As for the functional agent, it can be a nanoscale functional support. As substrates especially indicated, metals, glass, ceramics and enamels should be mentioned.

The object of the invention is to produce an abrasion resistant diffusion barrier blocking system in which a thin layer coating with high mechanical strength and a high diffusion blocking effect is present. This is achieved especially, without any heat treatment, without the need for high temperatures such as (eg a consolidation of layers from 450 ° C to 1000 ° C), so that the coating systems are also indicated for substrates, which cannot be exposed to such high temperatures. On the other hand, transparent layers can also be accepted so as to obtain coated substrates with the aforementioned characteristics, which are suitable for optical applications.

Coated substrates must, on the other hand, be capable of being made by a wet chemical process.

The object of the present invention could surprisingly be achieved by means of a plastic substrate with an insulating barrier blocking system, against diffusion resistant to abrasive wear, comprising:

A hard undercoat containing a coating composition based on thermally or photochemically curable or polymerizable blends in a polymer.

A coating layer, which can be obtained by adding a mass containing sol and / or solid nanoscale particles on the base layer that still has reactive surface groups and then receives a heat treatment or curing.

The hard base coat contains a coating composition from combinations thermally or photomechanically convertible by curing or polymerization into a polymer. The curable or polymerizable blends are blends or monomers, inorganic, inorganically modified organic or purely organic, for which mixtures can also be used. Preferably, organically modified organic compositions or mixtures of inorganically modified organic combinations and inorganic combinations will be used, wherein in the last case, they preferably contain at least 40 Mol .-%, being especially preferred those inorganically modified organic combinations preferably containing at least 60 Mol .-%. Overall, at least 20 Mol .-% are preferred, the content of at least 40 Mol .-% of all the organic-type polymerizable or curable blends used being especially preferred and / or inorganically modified organic blends.

In this case, polymerization is understood to mean all the usual reactions in polymerization, such as radical polymerization, polycondensation or polyaddition. The combinations hydrolyzable by polycondensation which take place in the last mentioned SolGel processes also apply in particular here. As for the condensates that originate here, they are also polymers. Concerning hardening (crosslinking), interlacing forming a three-dimensional network structure will be understood especially. Here also corresponds the condensation of hydrolyzable combinations giving rise to a three-dimensional lattice structure. The combinations can be contained in the coating compositions as monomers, and they can also be oligomers or (Pre) polymers that are at least partly polymerized or crosslinked. In coating compositions comprising inorganic or inorganically modified organic blends, this may be involved, eg, partially hydrolyzed and / or condensed.

In the case of coating compositions based on thermally or photochemically curable or polymerizable combinations in a polymer, it is preferably a coating composition based on combinations of elements that form glass and / or ceramics. As regards these combinations, they are in particular of the hydrolyzable and condensable type. The coating composition will preferably contain those combinations derived from Sol-Gel processes. For example, the glass and / or ceramic forming elements will be the elements of groups 3 to 6 and 12 to 15 of the periodic system or the elements called lanthanides. These elements are preferably those such as Si, Al, B, Pb, Sn, Ti, Zr, V and Zn, especially those between Si, Al, Ti and Zr, or their mixtures. However, combinations of other elements can also be used, especially those elements of group 1 and 2 of the periodic system (eg Na, K, Ca and Mg) or group 7 to 10 of the periodic system (eg Mn; Fe, Co and not). Preferably the combinations of the aforementioned elements are a total of less than 20 and especially not more than 10 Mol .-% of all the hydrolyzable monomeric combinations used.

For the coating composition, a coating composition operated by the Sol-Gel process based on inorganically modified organic blends, especially the silane blends, is especially preferred.

In particular, hydrolyzable silane combinations are used, preferably a part of the hydrolyzable silane compositions which contain at least one non-hydrolyzable substituent. Thus, for example, a composition for the coating of the preferred type comprises a polycondensate obtained by the Sol-Gel process, based on

ES 2 276 702 T3 (A) one or more silanes of general formula (I)

RaSiX₍4-_to) (I)

Where the R residues are the same or different and represent non-hydrolyzable groups, the X residues are the same or different and represent hydrolyzable groups or hydroxyl groups and for (a) the values ​​= 1, 2 or 3 correspond, where at least 40% of the silane substance (a) is greater than (o) or an oligomer resulting therefrom, and (B) optionally one or more combinations of elements with glass or ceramic formers.

In general formula (I) the hydrolyzable X groups, which can be the same or different from each other, such as hydrogen or halogens (F, Cl, Br, or I), alkoxy (preferably C_1-6-alkoxy such as eg methoxy, ethoxy, n-propoxy, i-propoxy and butoxy), aryloxy (preferably C₆-₁₀-aryloxy, such as eg phenoxy), acyloxy (preferably C_1-6-acyloxy, such as eg acetoxy or propionyloxy), alkylcarbonyl (preferably C_2-7-alkylcarbonyl, such as eg acetyl), amino, monoalkylamino or dialkylamino with preferably 1 to 12, or optimally 1 to 6 carbon atoms.

As for the non-hydrolyzable R radicals, which may be the same or different from each other, they may be non-hydrolyzable R radicals with a functional group or without a functional group.

The non-hydrolyzable radical R is, for example, alkyl (preferably C_1-8-alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl and t-butyl, pentyl, hexyl, octyl or cyclohexyl), alkenyl (preferably C_2-6-alkenyl, such as eg vinyl, 1-propenyl, 2-propenyl and butenyl), alkynyl (preferably C_2-6-alkynyl, such as eg acetylenyl and propargyl) and aryl (preferably C_6-10-aryl, such as eg phenyl and naphthyl). The radicals R and X can, if appropriate, have one or more customary substituents, such as halogens or alkoxy.

Among the special examples for the functional groups of the R moieties are the groups epoxy-hydroxy-, ether-, amino-, monoalkylamino-, dialkylamino-, amido-, carboxy-, vinyl-, acryloxy-, methacryloxy-, cyano-, halogen-, aldehyde-, alkylcarbonyl-, and phosphoric acid. These functional groups can be attached to the silicon atom through alkenylene groups-alkylene bridging groups, or arylene-, which can be cleaved by oxygen or -NH groups. The aforementioned bridge groups come from of the above-mentioned alkyl-, alkenyl-, or aryl moieties. The radicals R with a functional group preferably contain 1 to 18, or especially 1 to 8 carbon atoms. Of course, the radical R can also have more than one functional group.

In a preferred embodiment, the hydrolyzable silanes are used with a functional group, especially with the aforementioned functional groups, with preference being given to epoxy groups, such as a glycidyl- or glycidyloxy group, or (Met) acryloxy groups. These are in particular silanes or the general formula (I), where X is preferably C_1-4-alkoxy and especially preferred methoxy or ethoxy, and R is a residue of (C_1-6) -alkyleneglycidyloxy or a residue of (C_1-6) -alkylene- (Met) acryloxy, where (C_1-6) -alkylene pe corresponds to methylene, ethylene, propylene or butylene. Specific examples for the hydrolyzable silanes which can be used according to the invention can, for example, be taken from EP-A-195493. Due to the easy accessibility according to the invention, the γ-glycidyloxypropyl trimethoxysilanes, γ-glycidyloxypropyl triethoxysilane, tri- (m) ethoxysilane 3- (Meth) acryloxypropyl- and (Met) -3-trimethoxysilane are used with particular preference. acryloxypropyl. (Met) acryl corresponds to methacrylic or acrylic.

Whenever the above-mentioned silanes with a substituent hydrolyzed with epoxy groups are used, the use of a hardening catalyst is preferred, which is chosen from Lewis bases and alcoholates of titanium, zirconium or aluminum.

This curing catalyst acts in particular as a catalyst for the crosslinking of epoxy-epoxy or polyol-epoxy. The hardening catalyst will be added to the corresponding formulation in general in an amount of 0.01 to 0.6 Mol per Mol of epoxide group of the hydrolyzable silane. Amounts of the order of 0.02 to 0.4 and especially 0.05 to 0.3 Mol of curing catalyst per Mol of epoxy group will be preferred.

As for the Lewis-base, it is preferably a nitrogen combination. This type of nitrogen combinations can, for example, be selected from N-heterocyclics, phenols containing polycyclic amino groups, amines and ammonia (preferably as aqueous solutions). Specific examples of this are 1-methylimidazole, phenol 2- (N, N-dimethylaminomethyl) phenol 2,4,6-tris (N, N-dimethylaminomethyl) and undecene 1,8-diazabicyclo [5.4. 0] -7. Especially preferred among these combinations is 1-methylimidazole. Another class of nitrogen-containing Lewis bases which can be used according to the invention are the hydrolyzable silanes, which have at least one non-hydrolyzable residue, which comprises at least one primary, secondary or tertiary amino group.

The Ti, Zr or Al alcoholates are preferably one of the general formula (II)

M (OR ')_m (II)

Where M corresponds to Ti, Zr or Al, R "'is an alkyl group preferably with 1 to 4 carbon atoms (methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert-butyl ) or it is an alkyleneoxyalkyl group preferably with 1 to 4 carbon atoms as well as the alkylene as well as the alkyl unit (eg methylene, ethylene, 1,2-propylene,

ES 2 276 702 T3

1,3-propylene and 1,4-butylene for the alkylene unit and the above for the mentioned alkyl groups for example for the alkyl unit) and m 4 represents (M = Ti, Zr) or 3 (M = Al). Preferred hardening catalysts are A (OCH₂CH₂OC₄Hg)₃ (aluminum tributoxyethanolate) wherein the butyl group is preferably a n-butyl group, the secondary aluminum butylate and mixtures of aluminum tributoxyethanolate and the secondary aluminum butylated. For other particularities, it is necessary to refer to document DE-A-4338361.

Provided that the above-mentioned silanes are used with non-hydrolyzable substituents with a functional group, other hydrolyzable formulations of glass or ceramic-forming elements can also be used, together with the hydrolyzable silanes with functional groups, for which the amount of other hydrolyzable formulations does not it should preferably exceed 80 Mol-% and especially 60 Mol-%, referred to the total of the hydrolyzable combination used. They are preferably at least 10 and even better if they reach 20 Mol% of all the hydrolyzable combinations used than other hydrolyzable combinations, which of them or of the hydrolyzable silanes, are distinguished by at least one functional group of a non-hydrolyzable substituent.

As other components, especially for coating compositions based on combinations of hydrolyzable silanes with an epoxy group, an organic monomer, polygomer or polymer with at least one epoxy group or mixtures thereof can be used. Regarding these organic monomers, oligomers or polymers with epoxy groups, it is pe of known combinations which, according to the level of the art, are used as epoxy resins, casting resins and as epoxy reactive diluents.

As for other hydrolyzable combinations of glass or ceramic-forming elements, those of all the above-mentioned glass or ceramic-forming elements can be used. As an example for hydrolyzable groups, of these combinations we can refer to the assumptions for X introduced in formula (I). Preferred examples are the combinations of formula (II) and the combinations H listed in DE-A-4338361. Together with the hydrolyzable groups, the combinations can also have non-hydrolyzable groups. This is, however, not preferred except in the case of Yes. As an example, you can also refer to the assumption introduced for R in formula (I). Preferred are not more than 70 Mol-%, and specifically not more than 50 Mol-% of all hydrolyzable combinations, that is, combinations of elements that form glass or ceramics, which are not Si.

On the other hand, as hydrolyzable combinations, additionally or alone, for example one or more hydrolyzable combinations of silicon with at least one non-hydrolyzable radical containing from 5 to 30 fluorine atoms bound to the carbon atom, which in If necessary, they are separated by at least two silicon atoms.

As hydrolyzable groups, it is also possible to use those which are eg indicated for X in formula (I). Silanes of this type are described in detail in DE 41 18 184. These fluorinated silanes can, if appropriate, be used in general in an amount of 0.1 to 15, preferably 0.2 to 10, or especially in the best of in cases from 0.5 to 5% by weight, based on the weight of the hydrolyzable combinations.

Besides inorganic or organically modified inorganic blends, coating blends can also be based on pure organic blends (monomers). If appropriate, the thermally or photochemically curable or polymerizable combination can be replaced by a polymer, partially or completely by a corresponding polymer. This polymer based on organic compounds preferably still has reactive groups by means of which a subsequent polymerization or hardening can take place.

As long as the composition for the coating is only based on these polymers, from organic combinations, it is necessary that the reactive groups are present. As for the monomers and organic polymers that can be used, these are, for example, the usual monomers and systems for coating, known from the current state of the art, as described for example in Ullmanns, Technical Encyclopedia of Chemistry, volume 15, 4^to. 1978 edition, page 589.

Special examples of polymerizable monomers that provide a pure organic polymeric matrix include methacrylic acid, methacrylic acid ester, methacrylonitrile, styrene and styrene derivatives, alkenes (eg ethylene, propylene, butene , isobutene), halogenated alkenes (eg tetrafluoroethylene, chlorotrifluoroethylene, vinyl chloride, vinyl fluoride, vinylidene fluoride, vinylidene chloride, vinyl acetate, vinylpyrrolidone, vinyl carbazole and mixtures of monomers of this type. Also, unsaturated monomers of various types can be used, eg butadiene and ethylene dimethacrylate.

Possible corresponding polymers are known plastics, such as, for example, polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, polyolefins, polystyrene, polyamide, polyimide, polyvinyl compounds, such as polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetate and their corresponding copolymers, eg polyethylene-vinyl acetate, polyether, eg polyethylene terephthalate or polydiallyl phthalate, polyarylate, polycarbonate, polyether, eg polyoxymethylene, polyethylene oxide or polyphenylene oxide, polyether ketone, polysulfone, polyepoxides and fluoropolymers, such as polytetrafluoropolymers. Transparent polymers or their corresponding monomers are preferably used.

ES 2 276 702 T3

In a preferred embodiment, crosslinkable coating systems based on organic monomers or the corresponding polymers are used. These can be based on the above-mentioned polymers. In this case too, these are the usual systems known from the state of the art, which are, for example, cited in the above-mentioned Ullmann bibliography. As concrete examples of this are acrylic resins, alkyd resins, polyester resins (eg those that can be crosslinked by means of aminoplasts), polyurethane resins and epoxy resins with their corresponding monomeric systems.

Coating compositions based on thermally or photochemically curable or polymerizable compounds in a polymer can, moreover, be additive by means of additives known from the field of coating art. As an example, solvents, crosslinking agents, lubricating agents, solid nanoscale particles, polymerization initiators, photosensitizers or agents to facilitate distribution on surfaces can be mentioned. Examples as lubricants are surfactants, fluorsilanes or graphite. With regard to useful nanoscale solid particles, we have to refer you to the next clarification.

Since the delivery of the coating composition usually takes place on the substrate by a wet chemical process, the coating composition will preferably contain a dissolving agent. In this case, these are the dissolving agents usually used in the coatings sector. Examples of suitable solvents for especially with regard to combinations that form an organically modified inorganic matrix are alcohols, preferably lower aliphatic alcohols (Ci-C₈), such as methanol, ethanol, 1-propanol, i-propanol, and 1-butanol, ketones, preferably lower dialkyl ketones, such as acetone and methyl isobutyl ketone, ether, preferably lower dialkyl ethers, such as diethyl ether, or monoether diols, such as ethylene glycol or propylene glycol, with C-alcohols₁ -C₈, amides, such as dimethylformamide and mixtures thereof. Examples for high-boiling solvents are triethylene glycol, diethylene glycol diethyl ether, and tetraethylene glycol dimethyl ether. With respect to other solvents, especially with respect to combinations that form an organic matrix, it will be useful to refer again to the above-mentioned Ullmann bibliography.

The coating compositions can contain crosslinking agents. Crosslinking agents contain at least two reactive groups, which can react with the functional groups contained in coating formulations. The type of crosslinking agent will logically be oriented in the sense of the functional groups present in the coating composition. The selection of the suitable crosslinking agents is usual for the specialist. Thus, for example, they can be used with coating compositions containing epoxides, crosslinking agents with inorganic or organic groups with reactive hydrogen, eg isocyanate or hydroxyl groups.

The usable polymerization initiators are photoinitiators and thermal polymerization catalysts, which, depending on the composition used, will be selected from those known to the specialist. Examples include radical photoinitiators, radical thermoinitiators, cationic photoinitiators, cationic thermoinitiators, and any combinations thereof.

Concrete examples for usable radical photoinitiators are Irgacure® 184 (1-ketonehydroxycyclohexylphenyl), Irgacure^® 500 (1-ketonehydroxycyclohexylphenyl, benzophenone) and other photoinitiators supplied by CibaGeigy of the Irgacure® type; Darocur® 1173, 1116, 1398, 1174 and 1020 (available from Merck); Benzophenone, 2-chlorothioxanthone, 2-methyl thioxanthone, 2-isopropyl thioxanthone. Benzoin, 4,4'-benzoinadimethoxy, benzoin ethyl ether, benzoin isopropyl ether, dimethyl ketalbenzyl, acetophenone-1,1,1-trichlor, diethoxyacetophenone, and dibensuberone. Examples of radical thermoinitiators are, among others, organic peroxides, in the form of diacyl peroxides, peroxydicarbonates, alkyl esters, alkyl peroxides, parquet, acetone peroxides and alkyl hydroperoxides, as well as azo combinations. As concrete examples we would have here especially dibenzoyl peroxide, tert-butyl benzoate and azobisisobutyronitrile. An example of cationic photoinitiators would be Cyracure^® UVI-6974, while a preferred cationic heat initiator would be imidazole-1-methyl.

The photochemical curing or hardening can be carried out by the usual procedures, eg by means of ultraviolet radiation. On the other hand, other customary curing processes can also be applied, such as electron radiation curing and laser curing.

These polymerization initiators are generally used by a person skilled in the art in known amounts (eg 0.01-5% by weight or preferably 0.1-2% by weight, based on the total solids content of the coating composition. Of course, they can also be operated without polymerization initiator if this is not required.

In a preferred embodiment, the coating composition according to the Sol-Gel process will be obtained from hydrolyzable combinations. For this, the hydrolyzable combinations will be hydrolyzed and partially condensed by water, if necessary by heating or by acid or basic catalysis. Stoichiometric amounts of water can be used for this, as well as smaller and larger amounts. In the Sol preparation, appropriate parameters, eg the degree of condensation, the dissolving agent or the pH value, can be adjusted by the specialist without any problem to the desired viscosity of the coating composition. The coating composition will preferably be used in the form of the Sol for coating. Other peculiarities

ES 2 276 702 T3 with respect to the Sol-Gel process, can eg be taken from W. Noll, CEIME und Technologie der Silicone, 2^toedition, Editorial Chemie, 1968.

The coating compositions used preferably are found, for example, in EP-A-0 607 213 or in DE-A-4338361 from which full reference will be taken.

The nanostructured cover layer contains nanophases, eg in the form of solid particles and / or nanoscale Sol. Apart from this, it is in particular inorganic nanoscale solids and / or solids, which in some cases are superficially modified.

As for solid particles and / or nanoscale Sol, these are particles with a mean particle size (a mean particle diameter) of no more than 1000 nm, with no more than 200 nm being preferred, but even better if they do not measure more 100 nm, or especially preferable if they do not exceed 70 nm. An especially preferred particle size range is 1 to 100 nm, especially 5 to 50 nm.

The solid particles and / or nanoscale (inorganic) Sol can be made of materials according to convenience, preferably they consist however, of metals and especially of combinations of metals such as oxides (in some cases hydrated) such as ZnO, CdO, SiO₂, Uncle₂, ZrO₂, CeO₂, SnO₂, To the₂OR₃, In₂OR₃, The₂OR₃, Faith₂OR₃, Cu₂O, Ta₂OR₅, Nb₂OR₅, V₂OR₅, MoO₃ or WO₃; cetaceans such as sulfides (eg CdS, ZnS, PbS and Ag₂S), selenides (eg GaSe, CdSe and ZnSe) and tellurides (eg ZnTe or CdTe>), halides such as AgCl, AgBr, Agl, CuCl, CuBr, Cdl₂ and Pbl₂; carbides like CdC₂ or SiC; arsenides such as AlAs, GaAs and GeAs; antimonides such as InSb; nitrides like BN, AIN, Si₃N₄ and you₃N₄; phosphides like GaP, InP, Zn₃P₂ and Cd₃P₂; phosphates, silicates, zirconates, aluminates, stanates and the corresponding mixed oxides (eg indium oxide tin (ITO) and those with Perowskits structure such as BaTiO₃ and PbTiO3).

As for the solid particles and / or inorganic nanoscale sols used, these are preferably those oxides, sulfides, selenides and tellurides of metals and mixtures thereof. According to the present invention, nanoscale SiO particles will be especially preferred.₂, Uncle₂, ZrO₂, ZnO, Ta₂OR₅, SnO₂ and Al₂OR₃ (in any form of modification, especially as Bohmit, AlO (OH) as well as mixtures thereof.

The production of solid nanoscale particles used according to the invention can also be carried out in the usual way, for example by flame pyrolysis, plasma process, gas phase condensation process, colloidal techniques, precipitation processes, Gel-Sol process, controlled processes. nucleation and development, MOCVD procedures and (Micro) -emulsion procedures.

These procedures are described in the literature in a sufficiently comprehensive manner. In particular, metals (either by reduction or precipitation processes), ceramic oxidant systems (by precipitation of solutions), but also even salt-type or multi-component systems can be obtained. Salt-type or multi-component systems also include semiconductor systems.

The solid particles and / or the nanoscale Sol can be used as such or in a superficially modified way. In general, the use of solid particles and / or nanoscale Sol provided with polymerizable / polycondensable groups is preferred, especially with solid and / or Sol-nanoscale particles of SiO2, although very good results can also be obtained without surface modification. In this case, the commercially available silicic acid products can be used, for example siliceous saline, such as Levasile® from Bayer Ag, or pyrogenic silicic acid, eg the Aerosil range of products from Degussa. However, the non-surface modified particles can also be processed in situ.

The preparation of the nanoscale inorganic particles provided with polymerizable and / or polycondensible organic surface groups, which can be used according to the present invention, can be carried out mainly by two different processes, that is, either by surface modification of the already processed nanoscale inorganic particles or either by making these inorganic nanoscale particles, using one or more combinations, having the type of polymerizable and / or polycondensable groups. Both systems will be described more fully below.

The polymerizable and / or polycondensable organic surface groups may be groups at the discretion known to the specialist, which allow a radical, cationic or anionic thermal or photochemical polymerization or a thermal or photochemical polycondensation (if necessary, in the presence of of a suitable initiator, or of a catalyst). According to the present invention, surface groups having a (Met) acrylic, allyl, vinyl or epoxy group will be preferred, of which (Met) acrylic and epoxy groups will be especially preferred. As regards the groups which allow polycondensation, mention may be made first of all of the hydroxy-, carboxy and amino groups, with the help of which the ether-, ester- and amide combinations can be obtained.

According to the invention, it will also be preferred that the organic groups present on the surface of the nanoscale particles comprising polymerizable and / or polycondensable groups have a relatively low molecular weight. Especially the molecular weight should not exceed 500 for purely organic groups, 300 being preferable, or even better if it were 200. This logically does not exclude a clearly higher molecular weight for the combinations (molecules) comprising these groups (eg 1000 and above).

ES 2 276 702 T3

As already mentioned, polymerizable / polycondensable surface groups can be prepared basically following two procedures. If a surface modification is carried out on already processed nanoscale particles, in this case all combinations are indicated (preferably those with low molecular weight), which have one or more groups that react with the functional groups (existing on the surface). of solid nano-scale particles), (such as HO- groups in the case of oxides), or at least they could act alternately and on the other hand at least, those that have a polymerizable / polycondensable group. In this way, the corresponding combinations eg both the covalent as well as the ionic (salt type) or (Complex) -coordinative bonds formed on the surface of the solid nanoscale particles, while under the alternative simple effect, the alternative effects would have to be cited, for example. Dipol-Dipol, hydrogen bridging bonds and alternative Van der Waals effects. In any case, the development of covalent and / or coordinative combinations takes precedence. Specific examples relating to the surface modification of the nano-scale inorganic solid particles of the participating organic combinations are, for example, unsaturated carbonic acids such as acrylic acid and methacrylic acid (the ^ -dicarbonyl combinations (eg jd-diketone or carbonic acid ^ -carbonyl) with polymerizable double bonds, alcohols and unsaturated ethylenic amines, epoxides and the like. According to the invention, special preference for this type of combination is, for example, for the case of oxidizing particles, silanes that are hydrolytically condensable with at least (and preferably) one non-hydrolyzable moiety, which has a double-carbon bond. polymerizable carbon or epoxy ring. Preferably, silanes of this type correspond to the general formula (III):

Y - R¹ - SIR²3 (III) where Y equals CH₂= CR³-COO, CH₂= CH or glycidyloxy, R³ represents hydrogen or methyl, R¹ a divalent hydrocarbon residue with 1 to 10 carbon atoms, preferably 1 to 6, which optionally contains one or more groups of heterogeneous atoms (eg O, S, NH), separating neighboring carbon atoms from each other, and the remains R², identical or different from each other that form part of the general formula (I) for the aforementioned X groups and are specially selected from the alkylcarbonyl, alkoxy, aryloxy and acyloxy groups as well as allogenic atoms (especially F, Cl, and / or Br).

Preferably the R groups² they will be identical and selected from allogenic atoms, C1-4-alkoxy groups (eg methoxy, ethoxy, n-propoxy, i-propoxy and butoxy, C6-10-aryloxy (eg Phenoxy), C1-4-acyloxy (eg acetoxy) groups and propionyloxy) and C2-10-alkylcarbonyl groups (eg acetyl) Special preference for R moieties² they are the C 1-4 alkoxy groups and especially the methoxy and ethoxy groups.

Regarding the remains R¹ it is preferably an alkylene group, especially one with 1 to 6 carbon atoms, such as ethylene, propylene, butylene and hexylene. When Y equals CH₂= CH, R¹ it preferably means methylene and can in this case also mean a single bond.

Preferably Y represents CH2 = CR³-COO (where R³ preferably it is CH3) or glycidyloxy. Correspondingly, the silanes of the general formula (I) (meth) acryloyl oxyalkyltrialkoxysilane, such as 3-methacryloyl oxypropyltri (m) ethoxysilane and glycidyl oxyalkyltrialkoxysilane, such as 3-glycidyl oxypropyltri (m) ethoxysilane, are particularly preferred. .

If the production of the nanoscale inorganic particles is carried out using one or more combinations that have polymerizable / polycondensable groups already, a subsequent surface modification can be dispensed with (although this is logically possible as an additional measure).

The in situ preparation of nanoscale inorganic solid and / or Sol particles, with polymerizable / polycondensable surface groups, is explained in detail below, taking SiO2 particles as an example. For this reason, the SiO2 particles can, for example, be made by the Sol-Gel process, using at least one hydrolytically polycondensable silane together with at least one polymerizable / polycondensable group. Among silanes of this type, pe the above-described silanes of the general formula (I) without non-hydrolyzable substituents. In this case, it is also possible to use silanes which have a (non-hydrolyzable) hydrocarbon group without any functional group, such as phenyl or methyl trialkoxysilane.

Especially when an easy to clean coating surface is desired, it may be advisable to use a certain amount (eg up to 60 or especially up to 50 percent of the gram molecule, based on all the silanes used) of the above-mentioned silanes used with residues (not hydrolyzable) containing fluorine.

An (additional) component of the mass that contains solid particles and / or nanoscale Sol, can, for example, also be at least one monomer or one species of oligomer, which has at least one group that can react (polymerize or polycondense) with the nanoscale particles from the surface, present in the polymerizable / polycondensable groups. As species of this type, they are listed pe monomers with a polymerizable double bond such as acrylic acid ester, methacrylic acid ester, styrene, vinyl acetate, and vinyl chloride. As for other particularities regarding solid nanoscale particles, monomeric or oligomeric species and additionally applicable additives, it is necessary to refer to document DE-A-19746885, from which a complete reference will be extracted. Otherwise the additives listed above especially for the for8

ES 2 276 702 T3 mulation of the coating can also be used for the mass containing the solid nano-scale particles. Likewise, the specific examples listed there for additives can be used for the covering layer.

The mass containing the nanoscale particles will preferably be applied by a wet chemical process on the base coat. The mass is preferably in the form of a Sun or in the form of a fluid mass (suspension). The liquid component of this mass corresponds, for example, to water and / or organic solvent combinations and / or products (preferably mixable in water), which were added or processed during the elaboration of the nanoscale particles or their surface modification, together (as eg alcohols in the case of alkoxysilanes). Possibly suitable organic solvent products additionally used are, for example, alcohols, ethers, ketones, esters, amides and the like. Regarding this, it is advisable to refer to the above-mentioned solvent products. Apart from the dissolving products, the mass containing the nanoscale particles does not, in an embodiment present, contain any other polymerization initiator additives already listed above, apart from the fact that they are used in certain cases.

As for the substrate to be coated, it is a synthetic material substrate. This substrate can have any shape to choose, such as plate, sheet, moon or any irregular shape. Since a special advantage of the present invention is that it can have anti-diffusion barrier layers resistant to abrasive wear, without having to be exposed to high temperatures, hence the invention is logically especially suitable for heat-sensitive substrates, such as substrates of synthetic material. Examples of these plastic substrates are polyethylene, polypropylene, polyacrylate, polymethyl methacrylate, polymethyl acrylate, polyvinylbutyral, polycarbonate, polyurethane, ABS copolymers or polyvinyl chloride. Taking into account that the coating systems referred to in the invention can also be made without any problem of transparent material, in any case plastic materials will be preferred for transparent substrates.

The substrate can be pre-treated in the usual way, such as by cleaning, degreasing, anti-corrosion treatment, polishing, in order to provide better adhesion to the coating. The substrate can, for example, be provided with an undercoat or with a common primer, such as silanes or aminosilanes, previously treating with appropriate procedures such as plasma-Ar / O₂ either with a corona discharge or even blasting.

Both the coating composition for the base coat, as well as the mass for the top coat, will preferably be applied by wet chemical processes, especially in the form of a Sol applied to the substrate. These can be applied in any usual way, such as by spraying, spraying, casting, by brushing, by electro-dipping, by dipping or overflow coating or spinning. The base layer preferably has a dry thickness of the order of 1-50 µm, a thickness of 3-30 µm being preferred, and in an optimal case of 5-10 µm. The covering layer or each of them preferably has a dry thickness of the order of 100-1000 nm, with 150-500 nm being preferred and 200-300 nm optimally.

The coating composition for the base coat will be chosen so as to form a hard base coat. The hardness of coatings can be determined in various ways, such as by means of a crack test. Some standardized methods are given eg in the above-mentioned Ullmann bibliography. By a hard base layer, it is preferably understood in this case a base layer, which has at least the same hardness, or preferably a higher hardness than the substrate to be coated.

The base coat coating composition must be exposed to such conditions after application that drying and / or complete or partial polymerization or hardening can take place, hence the operation in such a way that the base coat still contains reactive surface groups. .

In case of partial polymerization and / or hardening of the base coat, the coating composition, approximately after aeration, eg, can be thermally or photolytically treated to achieve initial drying and / or hardening. Marginal conditions, such as eg temperature, amount of radiation or duration of treatment, will be selected so that the base coat still contains reactive groups. This, pe It can be achieved by drying the applied base coat at a temperature of the order of room temperature without exceeding 100 ° C, preferably not exceeding 85 ° C, and in the best case, not even reaching 70 ° C .

In case of complete polymerization and / or hardening of the base coat, it will be necessary to apply a subsequent treatment to achieve reactive surface groups, for example by flame, plasma, corona, oxidative or reductive treatment or by coating with a primer.

As for the reactive groups, these are groups by means of which there is the possibility of providing a subsequent polymerization or curing. With regard to these reactive groups, it will be necessary to refer to the corresponding materials for the coating with the mentioned functional groups. These reactive groups in particular also include those hydrolyzable groups still present in coating compositions based on inorganically or organically modified blends (such as, for example, alkyl MO, glass or ceramic-forming elements M as Si) and those which were condensed after hydrolysis. providing hydroxyl groups (eg M-OH, glass or ceramic-forming elements M as Si) that were not yet condensed eg into siloxane groups. By means of these groups, further condensation can still take place. Preferred examples of available reactive groups are hydroxyl groups, elemental hydrolyzable groups.

ES 2 276 702 T3 to form ceramics or glass (eg alkyl MO, M-OH), epoxide groups and (meth) acryloxy groups. Thanks to the reactive groups, there is also sufficient reactivity to achieve sufficient adherence.

On the still reactive surface groups present in the base layer, the nanostructured cover layer is then applied and then cured or heat treated. Curing or hardening can eg be carried out thermally or photochemically. Regarding the possible curing processes, refer to the procedures described for the base coat. On the other hand, it is assumed that this happens also in the crosslinking reactions between the nanoscale particles by means of the polymerizable / polycondensible surface groups that may be present. Especially when using nanoscale particles, without polymerizable / polycondensable surface groups, a heat treatment is carried out. Without being bound to a theory, it is assumed that this takes place for bonding reactions (eg on the silanol groups, still present) or in the condensation reactions. Of course, it can also occur in heat treatment and also in hardening reactions.

The thermal hardening or the thermal treatment, is carried out in any case at temperatures not exceeding 200 ° C, being preferred from 60 to 160 ° C, and especially, in the best of cases from 120 to 130 ° C. There is also the possibility of applying temperature levels that are well below the temperatures that are usually necessary to achieve consolidation and sintering (usually below 450 ° C). However, diffusion blocking barrier layers are achieved which are extraordinarily resistant to abrasive wear. This is somewhat surprising, since by direct addition of masses containing nanoscale particles onto a substrate no suitable coating can be obtained. It is suspected that also the alternating effects between the reactive groups still present in the coating mass and the reactive groups in the mass used for the covering layer play a role, eg in the sense that they favor a bond between the layers. through adherence.

It was found that the gas penetration rate (permeation) was considerably reduced. The abrasive wear values ​​determined by a Taber abrasimeter after 1000 cycles, measured as a percentage loss of scattered light, partly reached no more than 1%. On the contrary, through the loss of scattered light in glass, they gave a value of 1.5%, with transparent plastics 30-60% and through the usual resin layers of 3-20%.

The abrasive wear resistant diffusion barrier system, to which the invention relates, applied on the substrate, serves as a protective layer. Its fields of application are coatings for machines, floors, building elements, instruments, rotors, consumer objects, service elements, transparent plastic materials, glazing, displays, beverage containers, furniture, jewelery as well as for the aeronautical industry. and for interior design.

Examples

Example 1

Fabrication of a Sol-SiO₂ for the cover layer

98.87 g of tetraethoxysilane (TEOS) are mixed with 63.83 g of ethanol to prepare a solution A. Along with this, 63.83 g of ethanol, 72.50 g of deionized water and 1.38 g of HCl (37%) giving rise to a solution B. By mixing solutions A and B, a Sol is obtained when heating to a temperature of 30-40 ° C, to later stir at room temperature for 1.5 h and then store at -20 ° C.

Immediately before application, the Sol is diluted with ethanol, resulting in a solids content of 3% by weight.

Example 2

Elaboration of a Sol-SiO₂ superficially modified for the cover layer

For the elaboration of a Sol-SiO₂ alcoholic acid at 5.1% by weight, 247 g of tetrahetoxysilane (TEOS) were hydrolyzed and condensed with 76 g of ethanol in an acid solution of HCl (76 g ethanol + 76 g of H₂Or double distilled + 5.8 g of HCl, 37% in water). Glycidyloxypropyl trimethoxysilane (GPTS) was added in a weight ratio of SiO₂ : GPTS of 4: 1 and the Sol thus obtained, was stirred for 5 h at a temperature of 50 ° C. Alternatively, instead of glycidyloxypropyl trimethoxysilane, methacryloxypropyl trimethoxysilane (MPTS) can be used in a corresponding proportion by weight.

Example 3

Elaboration of a Sol-SiO₂ for the cover layer

For the elaboration of a Sol-SiO₂At 3% by weight, 1.95 g of silica sol ("Levasil 200S / 30" from Bayer), 43.35 g of ethanol and 3.00 g of tetraethoxysilane (TEOS) are mixed and stirred for 18 h at temperature ambient.

ES 2 276 702 T3

Example 4

Elaboration of a Sol-CeO₂/ SiO₂ for the cover layer

For the preparation of a Sol-CeO₂/ SiO₂ At 10% by weight, 25 g of ethanol, 10.0 g of a 20% by weight Zeroxid suspension and 5.0 g of tetraethoxysilane (TEOS) are mixed, stirring for 24 h at room temperature.

Example 5

Preparation of a Sol-TiO₂ for the cover layer

For the preparation of a nanoparticle Sol-TiO2, 2.1 g of tetraisopropyl orthotitanate were added in a mixture of isopropanol, 0.981 g concentrated with HCl (37% by weight in water) and 0.105 g of H₂O and stirring was carried out for 24 h at a temperature of 25 ° C. Then 2 g of MPTS were added to 200 g of Sol-TiO2 and it was stirred countercurrently for 5 h at a temperature of 50 ° C. A part of the isopropanol (10 g) was distilled off in vacuo and 14 g of 2-isopropoxyethanol and the photoinitiator UVI® 6974 (Union Carbide) were added. Alternatively, the same amount of GPTS can be used instead of MPTS.

Example 6

Development of a cladding system

Application of primer solution

PC plates (Makrolon 3103) of a size of 10 x 10 cm were used² as a substrate. The primer solution (2% by weight of γ-aminopropyl triethoxysilane in isopropanol) was applied by the spin coating procedure (conditions: application volume: 3 ml; spin speed: 1500 rpm; acceleration: 0.5 ; duration: 10 s). Curing was carried out at 130 ° C (30 min) in an oven with circulating dry air.

Hard base coat application

After applying the primer, a hydrolyzable epoxysilane-based hard coating system was applied. Also, using a spin coating system (conditions: application volume: 4 ml; spin speed: 600 rpm; acceleration: 05; duration 10 s). This base coat was then cured at 80 ° C (5 min) in an oven with circulating dry air.

Cover coat application

After the base coat was applied, a coating Sol was applied for the top coat also by the spin coating system (conditions: application volume: 3 ml; spin speed: 1500 rpm; acceleration: 05; duration 10 s). The curing process was then carried out. This was carried out at 130 ° C (for 2 h) in an oven with circulating dry air.

Characterization of the layers

A layer system was achieved whose adhesion according to the grid / tape cutting test (DIN 53151 and respectively DIN 58196-K2) gave very good results (GT / TT = O / O). The loss of scattered light according to 1000 cycles in a test with a Taber abrasimeter (DIN 52347 / abrasive wheel CS.10F / load 2 x 500 g / height of the suction nozzle nose: 3 mm) gave as a result between 1 and 3%. (These values ​​refer to different samples, which were tested by different people on different days, to obtain statistical confidence). The layer thickness (dry) of the hard layer applied was about 5 pm. The layer thickness (dry) of the cover layers, measured on a profilometer, gave approximately 200 to 300 nm.

The determination of the diffusion rates was carried out using a Permatran-W 3/31 from Mocon at 25 ° C and at 100% relative humidity of the air. The diffusion rates of the water vapor are currently up to 20% below the diffusion rates of the uncoated sheets.