EP1282673A2

EP1282673A2 - Scratch-resistant coating

Info

Publication number: EP1282673A2
Application number: EP01938083A
Authority: EP
Inventors: Peter Bier; Peter Capellen; Renate Weller
Original assignee: Bayer AG
Current assignee: Covestro Deutschland AG
Priority date: 2000-04-17
Filing date: 2001-04-04
Publication date: 2003-02-12
Also published as: MXPA02010226A; BR0110106A; CA2406175A1; US6824875B2; CN1196757C; JP2003534400A; US20030194561A1; AU2001263834A1; IL152276A0; KR20020093918A; WO2001079368A3; DE10018935A1; TW585891B; CN1423682A; WO2001079368A2

Abstract

The invention relates to scratch-resistant coatings comprising a primer layer (G) which adheres to a substrate that is to be coated and a scratch-resistant layer (K) which adheres to the primer layer (G). Said primer layer (G) contains a cured epoxy resin that can be obtained from curing agents and multi-functional epoxy compounds and the scratch-resistant layer (K) can be obtained from hydrolysable silanes containing epoxide groups. The inventive coatings are particularly stable vis-à-vis water corrosion. The invention also relates to products coated with said coatings.

Description

Scratch-resistant coating

The present invention relates to scratch-resistant coatings comprising a primer layer (G) adhering to a substrate to be coated and one on the

Primer layer (G) adhesive scratch-resistant layer (K), wherein the primer layer (G) contains a hardened epoxy resin which is obtainable from hardener and multiply epoxy-functional compounds, and wherein the scratch-resistant layer (K) is obtainable from hydrolyzable silanes containing epoxy groups Coatings are particularly stable against the attack of water.

The present invention further relates to products coated with these coatings.

To protect materials from harmful environmental influences, they are often provided with a coating. Coatings based on siloxane, also known as siloxane layers, have proven to be particularly suitable. give a scratch-resistant and chemical-resistant surface. The siloxane layers are therefore also called scratch-resistant layers (K).

In order to ensure good adhesion of the particularly hard scratch-resistant layer (K) to the mostly softer substrates, an intermediate layer, also called a primer layer (G) or primer layer, is often applied between the substrate and the scratch-resistant layer (K). The function of this primer layer (G) is to compensate for the different expansion coefficients of the substrate and the scratch-resistant layer (K) and to ensure good adhesion of the layers to the substrate.

The primer layer (G) is intended to prevent the protective scratch-resistant layer (K) from detaching from the substrate and preventing it from cracking under environmental influences such as heat, cold, dryness, moisture, chemicals, etc. Long-term attack by hot water is particularly critical for the scratch-resistant layer (K).

Primer layers (G) and their use in combination with scratch-resistant layers based on siloxane (K) as well as products equipped with them, in particular those made of polycarbonate, are described in the following documents: DE-A 2 917 837, DE-A 2 947 823, DE- A 2 950 295, DE-A 3 014 581, DE-A 3 014 772, US-A 4 243 720, DE-A 3 044 804. This describes primer layers (G) which are produced by thermal and / or radiation-induced polymerization of Acrylic monomers, preferably on polycarbonate, are produced.

The acrylic monomers, such as methyl methacrylate, hydroxyethyl acrylate, ethyl methacrylate, glycidyl methacrylate, methacryloxypropyltrimethoxysilane and others, which are mostly used as a mixture, are diluted with organic solvents or dispersed in water on the substrate by flooding, dipping, spraying or other customary painting techniques and then applied by thermal means or radiation-induced reaction cured. This creates the primer layer (G).

The scratch-resistant layers based on siloxane (K) are then applied to the primer layers (G) in analogous application processes.

DE-A 3 121 385, EP-A 0 340 565 and US-A 5 041 313 describe primer layers (G) in which the finished polyacrylic polymers are already dissolved in organic solvents or used as aqueous dispersions instead of the acrylate monomers still to be polymerized. The advantage of these systems is that only drying and no reaction step is required. These primer layers (G) are mainly described and used in combination with special siloxane systems.

The siloxane systems, which belong to the prior art, are essentially thermosetting systems, which are preferably caused by a condensation reaction Network formation of Si-O-Si links. Other networking mechanisms can also run in parallel.

Such systems are e.g. described in US-A 3 790 527, 3 865 755, 3 887 514, 4 243 720, 4 278 804, 4 680 232, 4 006 271, 4 476 281, DE-A 4 001 045, 4 122 743,

4 020 316, 3 917 535, 3 706 714, 3 407 087, 3 836 815, 2 914 427, 3 135 241, 3 134 777, 3 100 532, 3 151 350, 3 005 541, 3 014 411, 2 834 606, 2 947 879, 3 016 021, 2 914 427 and 4 338 361.

Particularly high, glass-like scratch resistance is achieved with coatings that are obtainable from hydrolyzable silanes containing epoxy groups, as described in US Pat

5 134 191, DE-A 4 020 316 and WO 98/05198 are described.

The primer layers (G) known from the prior art, if they are used as an intermediate layer between the particularly scratch-resistant siloxane layers which are obtainable from hydrolyzable silanes containing epoxy groups and a substrate, in particular polycarbonate, are not suitable for detaching the scratch-resistant coating to prevent long-term attack by hot water (more than 4 days).

The object of the present invention is therefore to provide scratch-resistant coatings comprising a primer layer (G) adhering to a substrate to be coated and a scratch-resistant layer (K) adhering to the primer layer (G), which do not have the disadvantages of the prior art. In particular, the coatings should adhere well, are crack-resistant, chemical-resistant and, in particular, extremely water-stable.

It is also an object of the present invention to provide products which are coated with these coatings. A particularly good adhesion of a scratch-resistant layer (K), which can be obtained from hydrolyzable silanes containing epoxy groups, to substrates is surprisingly achieved if a layer of a hardened epoxy resin is used as the primer layer (G) between the substrate and the scratch-resistant layer (K). Such scratch-resistant coatings are also particularly stable against the attack of hot water.

The present invention therefore relates to the use of compositions comprising hardeners and multiply epoxy-functional compounds for the production of primer layers (G) in coatings comprising these primer layers (G) and a scratch-resistant layer (K) adhering to the primer layer (G), the scratch-resistant layer (K ) is available from hydrolyzable silanes containing epoxy groups.

The present invention furthermore relates to a coating comprising a primer layer (G) adhering to a substrate to be coated and a scratch-resistant layer (K) adhering to the primer layer (G), characterized in that the primer layer (G) contains a hardened epoxy resin which consists of Harder and multiply epoxy-functional compounds are available, and that the scratch-resistant layer (K) is available from hydrolyzable silanes containing epoxy groups.

A preferred embodiment of the present invention is a coating according to the invention, the hardener being selected from the group consisting of amines, anhydrides and mixtures of both, and the multiply epoxy-functional compounds being selected from the group consisting of aromatic glycidyl compounds, cycloaliphatic glycidyl compounds, heterocyclic compounds Glycidyl compounds, cycloaliphatic and aliphatic epoxy compounds and mixtures of these compounds, which can serve as starting materials for epoxy resins, and the hydrolyzable silanes containing epoxide groups are selected from the group consisting of

Compounds of the general formulas (I) or (II):

H) - CH— CH ₂ -Si (OR ⁶ ) ₃ (II)

being in both

R ^{5 is} a divalent hydrocarbon radical with a maximum of 9 carbon atoms or a divalent radical with a maximum of 9 carbon atoms, consisting of C, H and O atoms, the O atom being present as an ether bond radical, and

R ^{6 is} an aliphatic hydrocarbon radical with a maximum of 4 carbon atoms, an acyl radical with a maximum of 4 carbon atoms or a radical of the formula (CH ₂ CH2θ) _n Z, in which n is at least 1 and Z is an aliphatic hydrocarbon radical with a maximum of 4 carbon atoms, and

m is 0 or 1,

Compounds of the general formula (III)

R ₃ SiR '(III) in which

R are the same or different and represent a hydrolyzable group and

R 'represents a glycidyl or glycidyloxy (C _j . ₂ o) alkylene radical and mixtures of these compounds.

Such a coating is particularly preferred, the multiply epoxy-functional compounds being cycloaliphatic epoxy compounds which can serve as starting materials for cycloaliphatic epoxy resins.

Furthermore, a preferred embodiment of the present invention is provided by a coating according to the invention, the hardener being selected from the group consisting of amines, anhydrides and mixtures of both, and the multiply epoxy-functional compound being selected from the group consisting of bisphenol A diglycidyl ether following formula

where n = 0 to 30,

3,4'-Epoxycyclohexane carboxylic acid 3,4'-epoxycyclohexylmethyl ester represented by the following formula

Bis (3,4-epoxy-cyclohexylmethyl adipate of the following formula

3- (3,4'-Epoxycyclohexyl-2,4-dioxa-spiro [5,5] -8,9-epoxyundecan of the following formula

and mixtures of these,

and wherein the hydrolyzable silanes containing epoxide groups are selected from the group consisting of 3-glycidyloxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and wherein the scratch-resistant layer (K) is additionally a particulate material selected from the group consisting of oxide or hydrated oxide of Si, Al, Ti, Zr, Zn, Sn or Ce with a particle size in the range of 2 to 50 nm and where for the preparation of the scratch-resistant layer (K) additionally compounds (C) selected from the group consisting of Si (OCH3) 4, Si (OC ₂ H ₅ ) ₄ , CH ₃ -Si (OC ₂ H ₅ ) 3, (CH ₃ ) ₂ Si (OCH ₃ ) 2 and (CH ₃ ) ₂ Si (OC ₂ H ₅ ) ₂ are used and wherein for the preparation of the scratch-resistant layer (K) additionally a compound (D) selected from the group consisting of aluminum trimethoxyethanolate, aluminum triisopropoxyethanolate, aluminum triethoxyethanolate and aluminum tris (n-butoxyethanolate) is used.

Furthermore, it is a preferred embodiment of the present invention a coating according to the invention, the scratch-resistant layer (K) additionally containing a particulate material with a particle size of 1 to 100 nm.

The present invention furthermore relates to coated products comprising a coating according to the invention and a substrate.

Coated products containing a coating according to the invention and a substrate containing wood, textiles, paper, stone goods are preferred. Metals, glass, ceramics or plastics. Polycarbonate is particularly preferred.

A preferred embodiment of the present invention are plates, glasses, optical lenses, automobile windows or plastic lenses containing a coated product according to the invention.

The coatings according to the invention have many advantages. They are very stable to hydrolysis and very scratch-resistant.

The primer layer (G) according to the invention contains a hardened epoxy resin and has a layer thickness of preferably less than 50 μm, particularly preferably less than 15 μm, very particularly preferably less than 1 μm.

The primer layer (G) is cross-linked by multi-epoxy functional

Compounds, hereinafter called epoxy compounds, are available with so-called hardeners, also called hardeners or crosslinking agents.

These multi-epoxy functional compounds and hardeners as well as their production and use are described for example in: Kunststoff Handbuch, Volume 10,

Thermosets, publisher: Prof. Dr. Wilbrand Woebcken, Carl Hanser Verlag, 1988 and in Kunststoff-Handbuch volume XI, polyacetals, epoxy resins, fluorinated polymers, silicones etc., publisher: Prof. Vieweg, Dr. Heron, Dr. Scheurlen, Carl Hanser Verlag, Munich, 1971 and in Epoxy-Resins, Chemistry and Technology, publisher: Clayton A. May, Yoshio Tanaka, Marcel Dekker Inc., New York,

1,973th

Epoxy compounds can be prepared by known processes, such as those described below. They are generally prepared by reacting substances with an active hydrogen and epichlorohydrin with subsequent dehydrohalogenation according to the following scheme: R - H CH ₂ CI

or by direct epoxidation of olefins by peracids:

R— CH = CHR '+ RXOOOH - * ~ R HR '+ R "COOH

Detailed manufacturing processes with reference to primary literature can be found in Encyclopedia of Polymer Science and Engineering, 2nd Edition, Volume 6, pages 322 to 382, published by John Wiley & Sons, or in Encyclopedia of Chemical Technology,

Fourth Edition, Volume 9, pages 730 to 755, or in Ullmann's Encyclopedia of Industrial Chemistry, Third Edition, 8th Volume, pages 431 to 437, Urban & Schwarzenberg, Munich-Berlin, or in Ullmann's Encyclopedia of Industrial Chemistry Fifth Edition, Volume A9, pages 531 to 563, VCH Verlagsgesellschaft mbH, D-6940 Weinheim.

Aromatic glycidyl compounds, for example, can be used as epoxy compounds. Examples for this are:

Bisphenol A diglycidyl ether of the following formula

in which n = 0 stands for pure product, n = 0 to 15 stands for technical product and n = about 2 or about 4 or about 12 stand for so-called technical advancement products;

Tetrabromo-bisphenol A diglycidyl ether (bromine content in the technical product about 47 to 50 wt .-%) of the following formula

Phenol novolak glycidyl ethers, which approximately have the following formula

where n is between 0.2 and 1.4 for technical products,

Kresolnovolak glycidyl ethers, which approximately have the following formula where n is between 1.0 and 4.0 for technical products,

Bisphenol-F-diglycidyl ether (offered as a mixture of isomers) with the following components

(10 to 15% by weight) (50 to 55% by weight)

the sum being 100% by weight;

Glyoxal tetraphenol tetraglycidyl ether of the following idealized formula (by-products are contained therein),

N, N-Diglycidyl-aniline of the following formula

p-aminophenol triglycid of the following formula

4,4'-diaminodiphenylmethane tetraglycide of the following formula

Cycloaliphatic glycidyl compounds, for example, can also be used as epoxy compounds. Examples for this are:

Tetrahydrophthalic acid diglycidyl ester of the following formula

Hexahydrophthalic acid diglycidyl ester of the following formula

Hydrogenated bisphenol A diglycidyl ether of the following formula

For example, heterocyclic glycidyl compounds can also be used as epoxy compounds. Examples for this are:

Triglycidyl isocyanurate of the following formula

Triglycidyl-bis-hydantoin of the following formula

Cycloaliphatic epoxy compounds which can serve as starting materials for cycloaliphatic epoxy resins can furthermore be used as epoxy compounds. Examples for this are:

3,4-Epoxycyclohexane carboxylic acid 3,4'-epoxycyclohexylmethyl ester of the following formula

Bis (3,4-epoxy-cyclohexylmethyl) adipate of the following formula

3- (3,4'-Epoxycyclohexyl) -2,4-dioxa-spiro [5,5] -8,9-epoxyundecane of the following formula

For example, aliphatic epoxy compounds which can serve as starting materials for aliphatic epoxy resins can also be used as epoxy compounds. Examples for this are:

Butane 1,4-diol diglycidyl ether of the following formula

O O / \ / \

CH.CHCH, - O- CH T ~ "H '2, C ^V H ^I " 2, CHrO-CH, CHCH

Polypropylene glycol 425 diglycidyl ether of the following formula

where n has a value such that an average molar mass of 425 g / mol (number average) results.

All epoxy compounds which can be used according to the invention have at least two

Epoxy groups.

Particularly preferred epoxy compounds are those which have no aromatic structures. Cycloaliphatic epoxy compounds which serve as starting materials for cycloaliphatic epoxy resins are very particularly preferred can. They provide coatings that are particularly stable against UV rays. Their production is described, for example, in Encyclopedia of Polymer Science and Engineering Volume 6, page 336, John Wiley & Sons Verlag and in US-A 2 716 123.

Anhydrides such as e.g. Phthalic anhydride, tetrahydro-, hexahydro-, methyltetrahydro-, endomethylene tetrahydro-, methylenedomethylene-tetrahydro-phthalic anhydride, pyromellitic acid, trimellitic acid, benzophenonetetracarboxylic acid anhydride, maleic anhydride / styrene copolymers or dodecene anhydride are used or dodecene anhydride.

Amines such as e.g. aromatic amines, cycloaliphatic amines, aliphatic amines, e.g. 4,4'-diaminodiphenylmethane, its o, o'-alkyl-substituted derivatives, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 2,4-diamino-3,5-diethyl-toluene, hydrogenated 4 , 4'-diaminodiphenylmethane, isophorondiamine, diethylenetriamine, triethylenetetramine, polyaminoamides based on diethylenetriamine or similar amines and fatty acids.

In addition, chain extension components (preferably phenols), polymerization initiators, polyaddition catalysts,

Flexibilizers and impact modifiers are used as they are known from the literature cited.

The primer layer (G) may also contain conventional additives such as e.g. Dyes, leveling agents, reactive thinners, inorganic or organic fillers and stabilizers, especially UV stabilization systems and infrared absorbers.

Hardeners and epoxy compounds can be used, for example, as aqueous dispersions or in organic solvents. Preferred organic solvents are alcohols, in particular isopropanol, ethanol, isopropyl glycol, Butylglycol, 4-hydroxy-4-methyl-2-pentanone or mixtures thereof. 4-Hydroxy-4-methyl-2-pentanone is very particularly preferred.

For easy handling, it has proven particularly favorable to use products which have already been crosslinked. This means that the epoxy compounds have already been reacted with a proportion of hardener and the hardener with a proportion of the epoxy compound. The final curing then takes place by mixing the two components at a higher temperature.

Hardeners and cross-linked epoxy compounds are e.g. from the company Ciba

Specialty Chemicals GmbH, D-79664 Wehr, Germany, offered under the name Araldite® and hardener as two-component systems for coating a wide variety of substrates.

To apply the primer layer (G) to the respective substrate, the surface of the substrate is usually first cleaned. In the case of plastic parts, washing with ethanol or isopropanol or cleaning in warm, surfactant-containing water in ultrasonic baths has proven effective.

After blowing off with ionized air (against electrostatic dust attraction; see

Brock, Thomas: Textbook of paint technology, Vincentz Verlag, Hanover 1998) the diluted one-component composition containing epoxy compounds and hardener is applied to the substrate by dipping, flooding, spraying, spin coating or other painting techniques. This creates the primer layer (G).

The layer thickness is regulated via the dilution (preferably 2 to 35% by weight solids content) and the coating parameters. The primer coat (G) is preferably allowed to dry to room temperature (20 to 23 ° C) until it dries dry. The final crosslinking is then carried out at higher temperatures, preferably at 90 to 130 ° C. The scratch-resistant layer (K) is then applied to this primer layer (G).

The scratch-resistant layer (K) according to the invention is obtainable from hydrolyzable silanes containing epoxy groups, preferably in combination with particulate materials having a particle size of 1 to 100 nm, preferably 2 to 50 nm.

According to the invention, epoxy group-containing hydrolyzable silanes, also called epoxysilanes, are compounds which on the one hand have at least one epoxy ring and at the same time have groups which form silanol structures under hydrolysis conditions.

Epoxysilanes as preferably used according to the invention are e.g. in US-A 2,946,701. These are compounds of the general formulas (I) or (II):

being in both

R ^{5 is} a divalent hydrocarbon radical with a maximum of 9 carbon atoms or a divalent radical with a maximum of 9 carbon atoms, consisting of C, H and O atoms, the O atom being present as an ether bond radical, preferably -CH ₂ OCH ₂ CH ₂ CH ₂ - and R ^{6 is} an aliphatic hydrocarbon radical with a maximum of 4 carbon atoms, an acyl radical with a maximum of 4 carbon atoms or a radical of the formula (CH ₂ CH ₂ O) _n Z, in which n is at least 1 and Z is an aliphatic hydrocarbon radical with a maximum of 4 carbon atoms, and

m is 0 or 1.

The preparation of these epoxysilanes is also described in US Pat. No. 2,946,701. Particularly preferred epoxysilanes are those compounds in which R ⁶ is methyl or ethyl. They are commercially available, including from Union

Carbide Corp., 39 Old Ridgebury Rd., Danbury, CT 06817-0001, USA and Sivento Chemie GmbH, Parsevalstr. 9A, D-40468 Düsseldorf, Germany, as:

A-187 or Dynasilan Glymo, that is 3-glycidyloxypropyltrimethoxysilane, or

A-186, which is 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

Further scratch-resistant layers (K) which are preferred according to the invention are described below.

US-A 5 134 191 discloses a scratch-resistant layer (K) which consists of epoxy group-containing organic silicon compound and inorganic submicron particles, i.e. with a particle size of less than 1 µm, e.g. Silicasol, is available and is curable with a minimal amount of an antimony compound as a curing catalyst. It can be used as a coating film for plastic articles that are used, for example, in optics. If necessary, the composition can also contain an aluminum compound.

A composition with even better scratch resistance, adhesion, paint viscosity and elasticity, which compared to the other compositions of the Prior art has a low tendency to gel and cloud is described in WO 98/05197.

A further scratch-resistant layer (K) preferred according to the invention is obtainable from at least one silicon compound (A) which has at least one hydrolytically non-cleavable radical which is bonded directly to silicon and contains an epoxy group, a particulate material (B) which is selected from oxides, Oxide hydrates, nitrides and carbides of silicon, aluminum and boron and of transition metals and which has a particle size in the range from 1 to 100 nm, a compound (C) of silicon, titanium, zirconium, boron, tin or vanadium and at least one hydrolyzable compound (D) titanium, zirconium or aluminum, characterized in that they are present in the following ratio:

1 mol of silicon compound (A), 0.42 to 0.68 mol of particulate material (B),

0.28 to 1.0 mol of compound (C) and 0.23 to 0.68 mol of compound (D).

These compositions, characterized by specific proportions of the components used, result in highly scratch-resistant scratch-resistant layers (K).

They have a significantly longer pot life.

To achieve rapid crosslinking of the scratch-resistant layer (K), a Lewis base (E) can also be used as a catalyst.

In addition, a hydrolyzable silicon compound (F) can be used with at least one non-hydrolyzable residue, which is preferably 5 to 30 directly on

Has carbon atoms bound fluorine atoms, these carbon atoms being separated from silicon by at least 2 atoms. The use of one of these Like fluorinated silane, the corresponding scratch-resistant layer (K) is additionally given hydrophobic and dirt-repellent properties.

In addition, a, preferably nonionic, surfactant (T) can be used to achieve long-term hydrophilic properties and / or an aromatic polyol (H) can be used to achieve corrosion-inhibiting properties (increase in water resistance to condensate).

The components A, B, C, D, E, F, T and H are explained in more detail below. It is stated what is preferred in the sense of the present invention.

The silicon compound (A) is a silicon compound which has 2 or 3, preferably 3, hydrolyzable radicals and one or 2, preferably one, non-hydrolyzable radical. The only or at least one of the two non-hydrolyzable residues has an epoxy group.

Examples of the hydrolyzable radicals are halogen (F, Cl, Br and I), in particular Cl and Br, alkoxy (in particular Cι_4-alkoxy, such as methoxy, ethoxy, n-propoxy, i-propoxy and n-butoxy, i-butoxy , sec-butoxy and tert-butoxy), aryloxy (especially C6_ ₁₀ - aryloxy, such as phenoxy), acyloxy (especially C _j ^ acyloxy, such as acetoxy and Proionyloxy) and alkylcarbonyl (for example acetyl).

Particularly preferred hydrolyzable radicals are alkoxy groups, especially methoxy and ethoxy.

Examples of non-hydrolyzable radicals without an epoxy group are hydrogen, alkyl, in particular C 1-4 alkyl (such as methyl, ethyl, propyl and butyl), alkenyl (in particular C ₂ _ ₄ -alkynyl, such as vinyl, 1-propenyl, 2- Propenyl and butenyl), alkynyl (in particular C1-4-aryl, such as phenyl and naphthyl), the groups just mentioned optionally having one or more substituents, such as halo gene and alkoxy. Methacrylic and methacryloxypropyl residues are also examples of non-hydrolyzable residues.

Examples of non-hydrolyzable residues with an epoxy group are, in particular, those which have a glycidyl or glycidyloxy group.

Examples of these silicon compounds (A) which can be used according to the invention can be found on pages 8 and 9 of EP-A 0 195 493.

Silicon compounds (A) which are particularly preferred according to the invention are those of the general formula

R ₃ SiR '(III) in which

R are identical or different, preferably the same and stand for a hydrolysable group, preferably C _j .4- alkoxy, and especially methoxy or ethoxy, and

R 'represents a glycidyl or glycidyloxy (Cι_ ₂ o) alkylene radical, in particular ß-glycidyloxyethyl, γ-glycidyloxypropyl, δ-glycidyl-oxybutyl, ε-glycidyl-oxypentyl, ω-glycidyloxyhexyl, ω- Glycidyloxyoctyl, ω-glycidyloxy nonyl, ω-glycidyloxydecyl, ω-glycidyloxydodecyl and 2- (3,4-epoxycyclohexyl) ethyl.

Because of its easy accessibility, γ-glycidyloxypropyltrimethoxysilane (hereinafter abbreviated as GPTS) is particularly preferably used according to the invention.

According to the invention, the particulate material (B) is an oxide, oxide hydrate, nitride or carbide of Si, Al or B or of transition metals, preferably Ti, Zr and Ce, with a particle size in the range from 1 to 100 nm, preferably 2 to 50 nm and particularly preferably 5 to 20 nm.

This material can be used in the form of a powder, but is preferably used in the form of a (in particular acid-stabilized) sol. Preferred particulate materials are boehmite, CeO, ZrO ₂ and TiO ₂ and titanium nitride.

Nanoscale boehmite particles with a particle size in the range from 1 to 100, preferably 2 to 50 nm and particularly preferably 5 to are particularly preferred

20 nm.

The particulate materials are commercially available in the form of powders and the production of (acid stabilized) sols therefrom is also known in the prior art. In addition, reference can be made to the manufacturing examples given below.

Boehmite sol with a pH in the range from 2.5 to 3.5, preferably 2.8 to 3.2, which can be obtained, for example, by suspending boehmite powder in dilute HCl is particularly preferably used.

The variation of the nanoscale particles is usually accompanied by a variation in the refractive index of the corresponding materials. For example, replacing boehmite particles with ZrO ₂ or TiO ₂ particles leads to materials with higher refractive indices, the refractive index according to the Lorentz-Lorenz equation being additively derived from the volume of the high-index component and the matrix.

The hydrolyzable compounds (C) according to the invention are described below. In addition to the silicon compounds (A), other hydrolyzable compounds (C) of elements from the group Si, Ti, Zr, Al, B, Sn and V are also used to produce the scratch-resistant layers (K) and preferably together with the silicon compound (A) or hydrolyzed the silicon compounds (A).

The compounds (C) are compounds of Si, Ti, Zr, Al, B, Sn or V of the general formula (IV) or (V)

R _X M ⁺⁴ R ' ₄ . _X (IV)

R _x M + 3R ' _3.χ (V) where

M a) Si ⁺⁴ , Ti ⁺⁴ , Zr ⁺⁴ , Sn ⁺⁴ or b) Al ⁺ 3, B ⁺ 3 or (VO) ⁺ 3,

R represents a hydrolyzable radical,

R 'represents a non-hydrolyzable radical and

x in the case of tetravalent metal atoms M (case a) 1 to 4 and in the case of trivalent

Metal atoms M (case b) can be 1 to 3.

If several radicals R and / or R 'are present in a compound (C), these can in each case be the same or different. X is preferably greater than 1. That is, the compound (C) has at least one, preferably more, hydrolyzable radicals.

Examples of the hydrolyzable radicals are halogen (F, Cl, Br and I), in particular Cl and Br, alkoxy in particular C ₁ . ₄ -alkoxy, such as methoxy, ethoxy, n-propoxy, i-propoxy and n-butoxy, i-butoxy, i-butoxy, sec-butoxy or tert-butoxy, Aryloxy, especially C ^ _Ö -. Aryloxy, such as phenoxy, acyloxy, in particular Cι_ ₄ - acyloxy, such as acetoxy, and propionyloxy, and alkylcarbonyl, such as acetyl. Particularly preferred hydrolyzable radicals are alkoxy groups, especially methoxy and ethoxy.

Examples of non-hydrolyzable radicals are hydrogen, alkyl, in particular C _j _ ₄ - alkyl, such as methyl, ethyl, propyl and n-butyl, i-butyl, sec-butyl and tert-butyl, alkenyl, especially C2.4- alkenyl such as, 2-propenyl and butenyl, in particular C ₂ ryl .4- alkynyl such as acetylenyl and propargyl, and aryl, in particular C6_ιo-, such as phenyl and naphthyl, wherein the groups just as vinyl, 1-propenyl alkynyl are optionally substituted may have one or more substituents, such as halogen and alkoxy. Methacrylic and methacryloxypropyl residues are also non-hydrolyzable residues.

Examples of compounds (C) which can be used according to the invention are given below.

Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (On- or iC ₃ H ₇ ) ₄ ,

Si (OC ₄ H ₉ ) ₄ , SiCl ₄ , HSiCl ₃ , Si (OOCCH ₃ ) ₄ , CH ₃ -SiCl ₃ , CH ₃ -Si (OC ₂ H ₅ ) ₃ , C ₂ H ₅ -SiCl ₃ , C ₂ H ₅ -Si (OC ₂ H ₅ ) ₃ ,

C ₃ H ₇ -Si (OCH ₃ ) ₃ , C ₆ H ₅ -Si (OCH ₃ ) ₃ , C ₆ H ₅ -Si (OC ₂ H ₅ ) ₃ ,

(CH ₃ O) ₃ -Si-C ₃ H ₆ -Cl,

(CH ₃ ) ₂ SiCl ₂ , (CH ₃ ) ₂ Si (OCH ₃ ) ₂ , (CH ₃ ) ₂ Si (OC ₂ H ₅ ) ₂ ,

(CH ₃ ) ₂ Si (OH) ₂ , (C ₆ H ₅ ) ₂ SiCl ₂ , (C ₆ H ₅ ) ₂ Si (OCH ₃ ) ₂ , (C ₆ H ₅ ) ₂ Si (OC ₂ H ₅ ) ₂ , (iC ₃ H _{7) 3} SiOH,

CH ₂ = CH-Si (OOCCH ₃ ) ₃ ,

CH ₂ = CH-SiCl ₃ , CH ₂ = CH-Si (OCH ₃ ) ₃ , CH ₂ = CH-Si (OC ₂ H ₅ ) ₃ ,

CH ₂ = CH-Si (OC ₂ H ₄ OCH ₃ ) ₃ , CH ₂ = CH-CH ₂ -Si (OCH ₃ ) ₃ ,

CH ₂ = CH-CH ₂ -Si (OC ₂ H ₅ ) ₃ , CH ₂ = CH-CH ₂ -Si (OOCCH ₃ ) ₃ ,

CH ₂ = C (CH ₃ ) -COO-C ₃ H ₇ Si (OCH ₃ ) ₃ , CH ₂ = C (CH ₃ ) -COO-C ₃ H ₇ Si (OC ₂ H ₅ ) ₃ ,

Al (OCH ₃ ) ₃ , Al (OC ₂ H ₅ ) ₃ , Al (OnC ₃ H ₇ ) ₃ , Al (OiC ₃ H ₇ ) ₃ , Al (OC ₄ H ₉ ) ₃ , Al (OiC ₄ H ₉ ) ₃ , Al (O-sek-C ₄ H ₉ ) ₃ , A1C1 ₃ , AlCl (OH) ₂ , Al (OC ₂ H ₄ OC ₄ H ₉ ) ₃ ,

TiCl ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OiC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ , Ti (2-ethylhexoxy) ₄ ,

ZrCl ₄ , Zr (OC ₂ H ₅ ) ₄ , ZR (OC ₃ H ₇ ) ₄ , Zr (OiC ₃ H ₇ ) ₄ , Zr (OC ₄ H ₉ ) ₄

ZrOCl ₂ , Zr (2-ethylhexoxy) 4,

as well as Zr compounds which have complexing residues, e.g. ß-diketone and methacrylic residues,

BCl ₃ , B (OCH ₃ ) ₃ , B (OC ₂ H ₅ ) ₃ ,

SnCl ₄ , Sn (OCH ₃ ) ₄ , Sn (OC ₂ H ₅ ) ₄ ,

VOCl ₃ , VO (OCH ₃ ) ₃ .

Compounds SiR ₄ are particularly preferably used, where the radicals R can be the same or different and stand for a hydrolyzable group, preferably for an alkoxy group with 1 to 4 carbon atoms, in particular for

Methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, sec-butoxy or tert-butoxy.

As can be seen, these compounds (C) (in particular the silicon compounds) also have nonhydrolyzable radicals which are a C-C double or

Have triple bond. Are such connections together with the If silicon compounds (A) are used, the composition used to produce the scratch-resistant layer (K) can also, preferably, also be introduced with monomers such as meth (acrylates) containing epoxy groups or acrylate groups. Of course, these monomers can also have two or more functional groups of the same type, such as poly (meth) acrylates of organic polyols. The use of organic polyepoxides is also possible. When the corresponding composition is thermally or photochemically induced, the organic species is polymerized in addition to the structure of the organically modified inorganic matrix, thereby increasing the crosslinking density and thus also the hardness of the corresponding

Coatings and coated products are increasing.

The compound (D) is preferably a compound of Ti, Zr or Al v. following general formula (VI)

M (R '") _m (VI) woπn

M stands for Ti, Zr or AI and

R '"can be the same or different and stand for a hydrolyzable group and

m is 4 (M = Ti, Zr) or 3 (M = AI).

Examples of the hydrolyzable groups R "'are halogen (F, Cl, Br and I, in particular Cl and Br), alkoxy (in particular Cι_g- alkoxy, such as methoxy, ethoxy, n-propoxy, i-propoxy and n-butoxy, i-butoxy, sec-butoxy or ter-butoxy, n-pentyloxy, n-hexyloxy), aryloxy (in particular Cg. ^ - aryloxy, for example phenoxy), acyloxy (in particular C _j . ₄ -acyloxy, such as acetoxy and Propinoyloxy) and alkylcarb- onyl (eg acetyl), or a Cι_6-alkoxy-C _ ₃ alkyl group, ie one of Cj-g- Alkylethylene glycol or C _j .g-alkyl propylene glycol derived group, wherein alkoxy has the same meaning as mentioned above.

M is particularly preferably aluminum and R '"is alkoxyethanolate, in particular methoxyethanolate, isopropoxyethanolate, ethoxyethanolate or n-

Butoxyethanolat.

The Lewis base (E) is preferably a nitrogen compound. Such nitrogen compounds can e.g. selected from N-heterocycles, amino group-containing phenols, polycyclic amines and ammonia (preferably as an aqueous solution).

Examples include 1-methylimidazole, 2- (N, N-dimethylaminomethyl) phenol, 2,4,6-tris (N, N-dimethylaminomethyl) phenol and 1, 8-diazabicyclo [5.4.0] -7-undecene , Among these compounds, 1-methylimidazole is particularly preferred.

Another class of nitrogen-containing Lewis bases which can be used according to the invention are hydrolyzable silanes which have at least one non-hydrolyzable radical which comprises at least one primary, secondary or tertiary amino group. Such silanes can be hydrolyzed together with the silicon compound (A) and then constitute a Lewis base built into the organically modified inorganic network.

Preferred nitrogen-containing silicon compounds are those of the general formula (VII)

R ³ SiR "(VII) wherein the radicals R are the same or different, preferably the same, and represent a hydrolyzable group, preferably C ₄ - alkoxy and in particular methoxy and ethoxy, and

R "stands for a non-hydrolyzable radical bonded to Si which comprises at least one primary, secondary or tertiary amino group.

Examples of such silanes are 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- [N'-2'-aminoethyl) -2-aminoethyl] 3-aminopropyltrimethoxysilane and N - [3- (Triethoxysilyl) propyl] -4,5-dihydroimidazole.

The Lewis base (E) is generally used in the corresponding compositions in an amount of 0.01 to 0.5 mol per mole of epoxy group of the silicon compound (A). Amounts in the range from 0.02 to 0.3 mol and in particular 0.05 to 0.1 mol Lewis base (E) per mol epoxy group are preferred.

The additionally usable hydrolyzable fluorinated silanes (F) are those which have at least one non-hydrolyzable radical which has 5 to 30 fluorine atoms bonded to carbon atoms which are separated from Si by at least two atoms. Such silanes are described in detail in DE-A 41 18 184. Examples include the following:

C ₂ F ₅ CH ₂ -CH ₂ -SiY ₃ , nC ₆ F ₁₃ CH ₂ -CH ₂ -SiY ₃ , nC ₈ F ₁₇ CH ₂ -CH ₂ -SiY ₃ , nC ₁₀ F ₂₁ CH ₂ -CH ₂ -SiY ₃ ,

(Y = OCH ₃ , OC ₂ H ₅ or Cl) iC ₃ F ₇ O- (CH ₂ ) ₃ -SiCl ₂ (CH ₃ ) nC ₆ F ₁₃ CH ₂ -CH ₂ -SiCl ₂ (CH ₃ ), nC ₆ F ₁₃ CH ₂ -CH ₂ -SiCl ₂ (CH ₃ ) 2. These fluorinated silanes are preferably used in an amount of 0.1 to 15% by weight, preferably 0.2 to 10% by weight and particularly preferably 0.5 to 5% by weight, based on the composition used for the preparation the scratch-resistant layer (K) is used.

The surfactant (G), which can be used to achieve a long-term anti-fogging effect and to increase the hydrophilicity of the coatings, is preferably a nonionic surfactant. Nonionic surfactants which are in liquid form at room temperature are particularly preferred. It is not only possible to use these surfactants during the preparation of the compositions, but they can also be subsequently diffused in at about 50 to 60 ° C. thermally. This is preferably done from an aqueous solution. Preferred surfactants are polyoxyethylene olyl ethers of different chain lengths (e.g. Brij® 92, 96 or 98 from ICI Surfactants, site of Deutsche ICI GmbH, Goldschmidtstraße 100, D-

45127 Essen, Germany), polyoxyethylene ethyl ether of different chain lengths (e.g. Malipal® 24/30 to 24/100 from Sivento Chemie GmbH, Parsevalstrasse 9A, D-40468 Düsseldorf, Germany) and Disponil® 05 from Henkel), sodium lauryl sulfate (e.g. Sulfopon® 101 Spezial from Henkel KGaA, Henkelstrasse 67, D-40191 Düsseldorf, Germany), lauryl pyridinium chloride (e.g.

Dehydquad C Christ® from Riedel de Haen AG, Wunstorfer Strasse 40, D-30926 Seelze, Germany).

The surfactant is preferably used in amounts of 0.1 to 35% by weight, based on the coating composition.

The optionally used aromatic polyol (H) preferably has an average molecular weight of at most 1000. Examples of such polyols are, for example, polyphenylene ethers which carry hydroxyl groups on at least 2 of the phenyl rings, and oligomers in which aromatic rings have a single bond, --O--, -CO-, -SO ₂ - or the like are bonded to one another and preferably have at least 2 hydroxyl groups bonded to aromatic groups.

Aromatic diols are particularly preferred aromatic polyols. Among these, particular preference is given to compounds having the following general formulas (VIII) and (IX)

being in both

X represents a (C _\ to Cg) alkylene or (Cj to Cg) alkylidene residue, a (Cg to C ₁₄ ) arylene residue, -O-, -S-, -CO- or -SO ₂ - and

n is 0 or 1.

X is preferably (C _j to C) alkylene or (C _j to C ₄ ) alkylidene, in particular -C (CH ₃ ) ₂ - and -SO ₂ -.

In addition to the OH groups, the aromatic rings of the compounds can also contain up to 3 or 4 further substituents, e.g. Wear halogen, alkyl and alkoxy.

Examples of aromatic polyols (H) which can be used are bisphenol A, 4,4'-dihydroxydiphenyl sulfone and 1,5-dihydroxynaphthalene, bisphenol A is preferred. The polyol (H) is preferably used in such amounts that 0.2 to 1.5 mol, particularly preferably 0.3 to 1.2 and very particularly preferably 0.6 to 1, per mole of epoxy ring of the silicon compound (A) , 0 mol, hydroxy groups of the aromatic polyol (H) are present.

The use of silicon compounds (A) which have at least two epoxy groups leads to coatings and coated products with improved condensation stability.

Preferred are the compositions which are used to produce the scratch-resistant layer

(K) are obtained by a process described in more detail below, in which a sol of material (B) with a pH in the range from 2.5 to 3.5, preferably 2.8 to 3.2, with a mixture of the other Components is implemented.

It is crucial for the composition that the amounts of the components used are in the specified amount ranges. It has been shown that, under this condition, compositions can be obtained which have significantly improved scratch resistance, adhesion, paint viscosity, gelation times, cloudiness and elasticity.

The hydrolyzable silicon compound (A) can optionally be prehydrolyzed together with the compound (C) using an acidic catalyst (preferably at room temperature, ie 20 to 23 ° C.) in aqueous solution, preferably with about half a mole of water per mole of hydrolyzable group - is set. Hydrochloric acid is preferably used as the catalyst for the pre-hydrolysis.

The particulate material (B) is preferably suspended in water and the pH is adjusted to 2.5 to 3, preferably 2.8 to 3.2. Hydrochloric acid is preferably used for acidification. If boehmite is used as the particulate material (B), a clear sol forms under these conditions. The compound (C) is mixed with the compound (A). The first portion of the particulate material (B) suspended as described above is then added. The amount is preferably chosen so that the water contained therein is sufficient for the semi-stoichiometric hydrolysis of the compounds (A) and (C). It is 10 to 70% by weight of the total amount, preferably 20 to

50% by weight.

The reaction is slightly exothermic. After the first exothermic reaction has subsided, the temperature is adjusted to approximately 28 to 35 ° C., preferably approximately 30 to 32 ° C., until the reaction starts and an internal temperature is reached which is higher than

25 ° C, preferably higher than 30 ° C and particularly preferably higher than 35 ° C. After the end of the addition of the first portion of material (B), the temperature is maintained for 0.5 to 3 hours, preferably 1.5 to 2.5 hours, and then cooled to about 0 ° C. The remaining material (B) is preferably added slowly at a temperature of 0 ° C. Then the compound (D) and optionally the Lewis base (E) are also preferably added slowly after the addition of the first portion of the material (B) at about 0 ° C. The temperature is then kept at about 0 ° C. for 0.5 to 3 hours, preferably for 1.5 to 2.5 hours, before adding the second portion of the material (B). Then the remaining material (B) is slowly added at a temperature of approx. 0 ° C. The dropped one

Solution is preferably pre-cooled to approximately 10 ° C. immediately before addition to the reactor.

After slowly adding the second portion of the compound (B) at about 0 ° C., the cooling is preferably removed so that the reaction mixture is warmed up to a temperature of more than 15 ° C. (to room temperature) slowly without additional temperature control.

All temperature information includes a deviation of + 2 ° C. A room temperature is understood to be a temperature of 20 to 23 ° C. To adjust the theological properties of the compositions, inert solvents may optionally be added at any stage of manufacture. These solvents are preferably alcohols which are liquid at room temperature and which are also formed during the hydrolysis of the alkoxides which are preferably used. Particularly preferred alcohols are Cj.g alcohols, especially methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, tert-butanol, n-pentanol, i-pentanol, n-hexanol, n-octanol and n-butoxy ethanol. Also preferred are C ^ _j glycol ethers, in particular n-butoxyethanol.

The compositions used to produce the scratch-resistant layer (K) may furthermore preferably contain conventional additives, such as, for example, Dyes, leveling agents, UV stabilizers, photoinitiators, photosensitizers (if photochemical curing of the composition is intended) and thermal polymerization catalysts.

The scratch-resistant layer (K) is applied to the substrate primed with epoxy resin using standard coating methods such as Dipping, brushing, brushing, knife coating, rolling, spraying, falling film application, spin coating and spinning.

If necessary, after the scratch-resistant layer (K) has previously dried at room temperature, the coated, primed and power-coated part is hardened. The curing preferably takes place thermally at temperatures in the range from 50 to 300 ° C., in particular 70 to 200 ° C. and particularly preferably 90 to 180 ° C., if appropriate under reduced pressure.

Under these conditions, the curing time should preferably be less than 200 minutes.

The layer thickness of the hardened strengthened layer (K) should preferably be 0.5 to 100 μm, preferably 1 to 20 μm and in particular 2 to 10 μm. If unsaturated compounds and / or photoinitiators are present, curing can also be carried out by irradiation, which may be followed by thermal post-curing.

The choice of substrates for coating is not limited. The compositions according to the invention are preferably suitable for coating substrates containing wood, textiles, paper, stone products, metals, glass, ceramics and plastics, and in particular are particularly suitable for coating substrates containing thermoplastic plastics, such as those e.g. in Becker / Braun, plastic pocket book, Carl Hanser Verlag, Munich, Vienna, 1992.

Preferred substrates essentially contain wood, textiles, paper, stone goods, metals, glass, ceramics or plastics, thermoplastic plastics being preferred among the plastics.

The substrates particularly preferably consist of wood, textiles, paper, stone goods, metals, glass, ceramics or plastics, thermoplastic plastics being preferred among the plastics.

The compositions are very particularly suitable for coating transparent thermoplastic materials and among them preferably polycarbonates, very particularly preferably bisphenol A homopolycarbonate and copolycarbonates based on bisphenol A and 1,1-bis (4-hydroxyphenyl) 3,3,5-trimethylcyclohexane). They are also particularly suitable for coating metals or metallized surfaces.

In particular, plates, glasses, optical lenses, automobile windows and plastic lenses can be coated with the compositions obtained. For the purposes of the present invention, polycarbonates are both homopolycarbonates and copolycarbonates; the polycarbonates can be linear or branched in a known manner.

Some, up to 80 mol%, preferably from 20 mol% to 50 mol%, of the carbonate groups in the polycarbonates can be replaced by aromatic dicarboxylic acid ester groups. Polycarbonates of this type which contain both acid residues of carbonic acid and acid residues of aromatic dicarboxylic acids built into the molecular chain are polyester carbonates. They should be subsumed under the generic term polycarbonates.

Polycarbonates can be produced by known processes. Suitable processes for the production of polycarbonates are e.g. the production from bisphenols with phosgene by the phase interface process or from bisphenols with phosgene by the process in the homogeneous phase, the so-called pyridine process, or from bisphenols with carbonic acid esters by the melt transesterification process. These production processes are e.g. described in H. Schnell, "Chemistry and Physics of Polycarbonates", Polymer Reviews, Volume 9, pp. 31 to 76, Interscience Publishers, New York, London, Sidney, 1964. The production processes mentioned are also described in D. Freitag, U Grigo, PR Müller, H. Nouvertne, "Polycarbonates" in Encyclopedia of Polymer Science and Engineering, Volume 11, Second Edition, 1988, pages 648 to 718 and in U. Grigo, K. Kircher and P.R. Müller "Polycarbonate" in Becker, Braun, Kunststoff-Handbuch, Volume 3/1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag Munich, Vienna 1992, pages 117 to 299.

The melt transesterification process is described in particular in H. Schnell, "Chemistry and Physis of Polycarbonates", Polymer Reviews, Volume 9, pp. 44 to 51, Interscience Publishers, New York, London, Sidney, 1964 and in DE-A 1 031 512, in US-A 3,022,272, in US-A 5,340,905 and in US-A 5,399,659. The polycarbonates have average molecular weights M _w (determined by measuring the relative viscosity at 25 ° C. in CH ₂ C1 ₂ and a concentration of 0.5 g per 100 ml CH ₂ C1 ₂ ) of preferably 12,000 to 400,000 g / mol, particularly preferably from 18,000 to 80,000 g / mol and very particularly preferably from 22,000 to 60,000 g / mol.

The present invention accordingly also relates to coated products, comprising substrates, preferably made of polycarbonate, and the coatings according to the invention.

The following examples illustrate the present invention.

Examples

Scratch-resistant coatings for the production of the scratch-resistant layer (K):

Scratch resistant lacquer Kl

Production according to DE-A 4 338 361

To produce a boehmite sol, 12.82 g of boehmite powder (AIO (OH); Disperal Sol P 3 from Condea Chemie GmbH, Überseering 40, D-22297 Hamburg, Germany) were mixed with 104.62 g of 0.1 N HC1. Subsequent ultrasound treatment (20 minutes) produced a transparent, colorless solution, to which 24.3 g was mixed with a mixture of 118.17 g GPTS (3-glycidyloxypropyltrimethoxysilane) and 62.50 g TEOS (tetraethylorthosilicate). The reaction mixture was stirred at room temperature for 2 hours and then 18.93 g of aluminum tributoxyethanolate were added while cooling with ice. The resulting clear sol became 2nd

Stirred at about 0 ° C for hours and then 93.14 g of the above boehmite sol and 79.30 g of butoxyethanol were added while cooling with ice.

Scratch-resistant paint K2 Manufactured according to WO 98/05198

Production of boehmite sol

129.04 g of boehmite powder (AIO (OH)) (Disperal Sol P3® from Condea) were added to 1290.40 g of 0.1N HCl with stirring and the pH was adjusted to conc. HC1 set to 3. The mixture was then stirred at room temperature for 14 h and the pH was then checked again.

Separately, 1181.7 g (5 mol) of GPTS and 625.0 g of TEOS (tetraethoxysilane)

(3 mol) mixed and stirred for 10 minutes. 267.3 g of the boehmite sol were added to this mixture using a metering pump at a flow rate of 20 g / min.

A few minutes after the addition, the sol warmed up to about 28 to 30 ° C. and was clear after about 20 minutes. The mixture was then stirred at room temperature for about 2 hours and then cooled to about 0 ° C. 378.54 g (1 mol) of Al (OEtOBu) ₃ were then added at 0 ° C. ± 2 ° C. at a metering rate of approx. 3 ml / min. After the addition had ended, the mixture was stirred at about 0 ° C. for a further 2 hours and then the remaining boehmite sol was likewise added at about 0 ° C. and a metering rate of about 13 ml / min. The reaction mixture obtained was then warmed to room temperature without temperature control. The coating agent obtained is then stored at + 4 ° C.

Scratch-resistant paint K3

Production according to DE-A 4 338 361

a) 19.8 g of glacial acetic acid, 210 g of distilled water and 227 g of isopropanol were added to 300 g of colloidal silica with 30% by weight SiO ₂ content. After thorough mixing, 900 g of methyltriethoxysilane were added and the mixture was heated to 60 ° C. with stirring. The mixture was left at this temperature for 4 hours and then another 1200 g of isopropanol was added to the mixture. After the product had cooled to room temperature, the slightly opaque solution was filtered.

b) 340 g of isopropanol, 190 g of tetraethoxysilane and 360 g of methyltriethoxysilane were placed in a vessel provided with a stirrer and reflux condenser. This mixture was mixed with 180 g of 0.05N hydrochloric acid and heated under reflux for 5 hours to carry out the cohydrolysis. After the reaction, the mixture was cooled to room temperature. The result is a solution which contains a partial hydrolyzate of tetraethoxysilane (5.1%, calculated as SiO ₂ ) and a partial hydrolyzate of methyltriethoxysilane (12.6%, calculated as CH ₃ SiO _lj5 ).

Before use as a coating material, the two components a) and b) were mixed together in a ratio of 1: 1 and in one Mixture of 60 parts by weight of n-butanol, 40 parts by weight of acetic acid and 20 parts by weight of toluene dissolved.

Scratch-resistant paint K4 Manufactured according to US-A 5 041 313

203 g of methyltrimethoxysilane were mixed with 1.25 g of glacial acetic acid. 125.5 g of ammonia-stabilized colloidal silica sol (Ludox AS® from Dupont, E.I. Dupont de Nemours and Company Inc., Wilsington, DE 19898, USA) and 41.5 g of distilled water were added to this mixture with stirring. The resulting solution was then stirred at room temperature for 16 to 18 hours and diluted with 370 g of a 1: 1 (parts by weight) mixture of isopropanol / n-butanol and provided with 19 g of 2,4-dihydroxybenzophenone as UV stabilizer. The mixture was then stirred for 2 weeks (ripening process).

Primers for the production of the primer coat (G):

Primer coat Gl

32 parts by weight

7 parts by weight HO CH ₂ CH ₂ -NH- (CH ₂ -CH ₂ -NH) ₃ -CH ₂ -CH ₂ -NH-CH ₂ CH ₂ -OH (ethoxylated tetraethylene pentamine)

3 parts by weight Pentamethylenimin

1258 parts by weight of 4-hydroxy-4-methyl-2-pentanone Primer G2

27 parts by weight Oligomeric bisphenol A diglycidyl ether of the following formula:

5 parts by weight Bisphenol F diglycidyl ether (as a mixture of isomers) from:

(10 to 15% by weight) (50 to 55% by weight)

(30 to 35% by weight)

7 parts by weight Ethoxylated tetraethylene pentamine

4 parts by weight Pentamethylenimin

1257 parts by weight of 4-hydroxy-4-methyl-2-pentanone

Primer G3

29 parts by weight Bisphenol A diglycidyl ether such as undercoat composition F

3 parts by weight Propylene glycol diglycidyl ether (M _n = 555) 8 parts by weight Ethoxy-hard tetraethylene pentamine

4 parts by weight Pentamethylenimin

1256 parts by weight of 4-hydroxy-4-methyl-2-pentanone

Primer G4

30 parts by weight Bis-3,4-epoxy-cyclohexylmethyladipat

7 parts by weight Ethoxy-hard tetraethylene pentamine

3 parts by weight Pentamethylenimin

1260 parts by weight of 4-hydroxy-4-methyl-2-pentanone

Primer G5

30 parts by weight triglycidyl

7 parts by weight Ethoxy-hard tetraethylene pentamine

3 parts by weight Pentamethylenimin

1260 parts by weight of 4-hydroxy-4-methyl-2-pentanone Primer G6

2 parts by weight Polymethyl methacrylate (Elvacite® 2041, Dupont de Nemours Corp.)

98 parts by weight Methylisopropylglykol

Base coat G7

2 parts by weight Polymethyl methacrylate (Elvacite® 2042, Dupont de Nemours

Corp.)

98 parts by weight Methylisopropylglykol

To prepare the primers G1 to G7, the appropriate solvent, such as 4-hydroxy-4-methyl-2-pentanone, methylisopropylglycol or n-butanol, was initially introduced at room temperature and the other additives were added in any order with stirring. The mixture was stirred until a clear, homogeneous solution was obtained. The solutions were kept at room temperature.

The following test pieces were produced and tested to test the hydrolysis stability of differently primed and then scratch-resistant coated polycarbonate parts:

First, plates made of bisphenol A homopolycarbonate (Tg = 147 ° C, M _w =

27500 g / mol) with the dimensions 105 x 150 x 4 mm cleaned with isopropanol by washing and blown dry with ionized air. The plates were then coated with the respective primer at an immersion speed of 70 cm min at room temperature and a rel. 40% humidity coated. After 30 minutes of evaporation to dryness, the plates were subjected to a 30-minute heat treatment in a convection oven at 130 ° C subjected. After cooling to room temperature, the plates primed in this way were each at an immersion speed of 70 cm / min, 40% rel. Air humidity and 18 ° C coated with one of the above scratch-resistant lacquers Kl to K4. After 20 minutes of evaporation, the coated plates were dried at 130 ° C. for 1 hour. The coated panels were made after curing

2 days at room temperature and 50% rel. Stored in humidity and then subjected to the following tests.

Hydrolysis stability: To check the hydrolysis stability, a

Cross-cut test according to standard EN ISO 2409: 1994 carried out after storage in water at 65 ° C and after storage in boiling water.

Water aging at 65 ° C: A closable glass vessel filled with deionized water was placed in one

Drying cabinet placed, the temperature was 65 + 2 ° C. After the tempering, the coated polycarbonate samples, on which a cross-cut / tape tear-off test had previously been carried out, were placed in the glass vessel. The samples were checked daily for their adhesion by the tape test on the original cross-cut. The storage period from which the first loss of liability in the tape test from 0 to 1 (EN ISO 2409: 1994) occurred was recorded and entered in the results table with water storage.

Cooking test: Here an open beaker was used, which was filled with deionized water. The vessel was insulated with a jacket made of expanded polystyrene (Styropor®). The water was stirred with a magnetic stirrer and brought to a boil. The samples were also cross-cut here and placed in the boiling water. The test procedure was the same as described above, except that the samples were checked every half hour. The storage time from which the first liability loss in the tape test of 0 was recorded was again recorded after 1 (EN ISI 2409: 1994) occurred. The times are entered as hours (h) in the cooking test in the results table.

Results

As the test results show, the polycarbonate sheets provided with the epoxysilane-based coatings (K1 and K2) according to the invention have excellent water stability if an epoxy resin primer layer (G) as shown in Eq. Between the polycarbonate and the scratch-resistant layer (K) , G2, G3, G4 and

G5 described exists. See experiments 1 through 5 and 7 through 12.

In comparison, the plates, which have a combination of a non-epoxysilane-based scratch-resistant lacquer (K3 and K4) and epoxy resin primer layers (Gl, G2, G3, G4 and G5) - comparative tests 15 to 24 - or a combination of epoxysilane based scratch-resistant lacquer (Kl or K2) with the polyacrylate primer layers (G6 or G7) described and used commercially in the literature, significantly lower water stabilities.

The test values of these comparative samples are a maximum of 5 days in the water aging test (65 ° C) and a maximum of one hour in the boiling test. The coatings according to the invention achieve corresponding values above 16 days and 4 hours.

Claims

Patentansprflche

1. Use of compositions containing hardener and multiply epoxy-functional compounds for the production of primer layers (G) in coatings comprising these primer layers (G) and one on the

Primer layer (G) adherent scratch-resistant layer (K), the scratch-resistant layer (K) being obtainable from hydrolyzable silanes containing epoxy groups.

2. Coating comprising a primer layer (G) adhering to a substrate to be coated and a scratch-resistant layer (K) adhering to the primer layer (G), characterized in that the primer layer (G) contains a hardened epoxy resin which consists of hardener and multiply epoxy-functional compounds is available, and that the scratch-resistant layer (K) is available from epoxy-containing hydrolyzable silanes.

3. Coating according to claim 2, wherein the hardener is selected from the group consisting of amines, anhydrides and mixtures of both and wherein the multiply epoxy-functional compounds are selected from the group consisting of aromatic glycidyl compounds, cycloaliphatic glycidyl compounds, heterocyclic glycidyl compounds, cycloaliphatic and aliphatic epoxy compounds and mixtures of these compounds, which can serve as starting materials for epoxy resins, and the epoxy group-containing hydrolyzable silanes are selected from the group consisting of compounds of the general formulas (I) or (II):

being in both

R ^{5 is} a divalent hydrocarbon radical with a maximum of 9

Carbon atoms or a divalent radical with a maximum of 9 carbon atoms, consisting of C, H and O atoms, where the O atom is present as an ether bond, and

R ^{6 is} an aliphatic hydrocarbon radical with a maximum of 4

Carbon atoms, an acyl radical with a maximum of 4 carbon atoms or a radical of the formula (CH ₂ CH ₂ O) _n Z, in which n is at least 1 and Z is an aliphatic hydrocarbon radical with a maximum of 4 carbon atoms, and

m is 0 or 1,

Compounds of the general formula (III)

R ₃ SiR '(III) in which

R are the same or different and represent a hydrolyzable group and

R 'represents a glycidyl or glycidyloxy (Cι_2o) alkylene radical

and mixtures of these compounds. Coating according to claim 3, wherein the multi-epoxy functional compounds are cycloaliphatic epoxy compounds, which can serve as starting materials for cycloaliphatic epoxy resins.

The coating of claim 2, wherein the hardener is selected from the group consisting of amines, anhydrides and mixtures of both, and wherein the multi-epoxy functional compound is selected from the group consisting of bisphenol A diglycidyl ether of the following formula

where n = 0 to 30,

Bis (3,4-epoxy-cyclohexylmethyl adipate of the following formula

and mixtures of these,

and wherein the hydrolyzable silanes containing epoxide groups are selected from the group consisting of 3-glycidyloxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and wherein the scratch-resistant layer (K) is additionally a particulate material selected from the group consisting of oxide or hydrated oxide of Si, Contains AI, Ti, Zr, Zn, Sn or Ce with a particle size in the range from 2 to 50 nm and, for the preparation of the scratch-resistant layer (K), additional compounds (C) selected from the group consisting of Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , CH ₃ -Si (OC ₂ H ₅ ) ₃ , (CH ₃ ) ₂ Si (OCH ₃ ) ₂ and (CH ₃ ) ₂ Si (OC ₂ H ₅ ) ₂ are used and wherein a compound (D) selected from the group consisting of aluminum trimethoxyethanolate, aluminum triisopropoxyethanolate, aluminum triethoxyethanolate and aluminum tris (n-butoxyethanolate) is additionally used for the production of the scratch-resistant layer (K).

Coating according to one of claims 2 to 4, wherein the scratch-resistant layer (K) additionally contains a particulate material with a particle size of 1 to 100 nm.

Coated products containing a coating according to one of claims 2 to 6 and a substrate.

8. Coated products containing a coating according to one of claims 2 to 6 and a substrate containing wood, textiles, paper, stone goods, metals, glass, ceramics or plastics.

9. Coated products according to claim 8, wherein the substrate contains polycarbonate.

10. plates, glasses, optical lenses, automobile windows or plastic lenses containing a coated product according to one of claims 7 to 9.