KR20010099852A - Coating Compositions Containing Cerium Dioxide - Google Patents

Abstract

The present invention relates to a coating composition comprising cerium dioxide. The coating composition is based on a hydrolyzable silane comprising an epoxy group. The present invention also relates to products coated with the composition and uses thereof.

Description

[0001] Coating Compositions Containing Cerium Dioxide [0002]

The present invention relates to a coating composition based on a hydrolyzable silane containing cerium dioxide and containing an epoxy group, a product coated therewith and a use thereof.

Suitable materials as coatings can be prepared from alkoxides, such as aluminum propanolate or aluminum butanolate, using a modified alkoxysilane by the sol-gel process. Such a sol-gel process is characterized in that a mixture of substantially the starting components is reacted to form a viscous liquid phase by a hydrolysis and condensation process. This synthetic method forms an organically modified inorganic basic structure with increased surface hardness compared to conventional organic polymers. A crucial disadvantage, however, is that a high level of storage stability (pot life) can not be achieved due to the high reactivity of the aluminum containing component. In addition, the resulting layer is still relatively soft compared to inorganic materials. The reason is that inorganic components in the system have a pronounced cross-linking action, but because of their small size, they do not have mechanical properties such as hardness and abrasion resistance, for example. Since the particle size present in this case is a few micrometers, the advantageous mechanical properties of the inorganic component can be fully utilized by so-called filled polymers. In this case, however, application in the optical field is no longer possible as the transparency of the material is lost. Small SiO ₂ (e.g. Aerosils (R) (Aerosils)) particles can be used in the manufacture of transparent layers with increased abrasion resistance. However, the level of abrasion resistance that can be achieved at low usable concentrations is similar to the system mentioned above. The upper limit of the amount of filler is determined by the high surface reactivity of the small particles causing agglomeration or excessive viscosity increase.

WO 95/13326 discloses a method of making an organically modified inorganic system that exhibits high optical transparency with greatly increased hardness compared to the systems described above. In addition, the publication describes a corresponding system suitable for hydrophilic coatings as well as organically modified inorganic systems suitable for protecting metal surfaces from corrosion. The composition comprises a particulate material selected from oxides, hydroxides, nitrides and carbides of Si, Al and B or transition metals and having a particle size in the range of 1 to 100 nm, preferably a boehmite and / or nonionic surfactant and Or aromatic polyol is added to at least one prehydrolyzed silicon compound containing an epoxy group and a radical directly bonded to Si. High scratch resistance is achieved by combining the prehydrolyzed silicon compound with the particulate material. On the other hand, the prehydrolyzed silicon compound is combined with a surfactant to produce a hydrophilic coating, while a prehydrolyzed silicon compound can be combined with an aromatic polyol to obtain a corrosion inhibiting coating. If desired, fluorinated silanes may be added to the manufacturing process to make hydrophobic or oil-based coatings, or Lewis bases or alcoholates may be added as crosslinking catalysts, or hydrolyzable compounds may be added have.

DE-OS 40 20 316 describes hydrolysable silane-based coatings which produce abrasion resistant and flexible coatings after curing. The coating can be obtained by reacting at least one silicon compound containing an epoxy group with water in a molar ratio of water to an existing hydrolyzable group of from 1: 1 to 0.4: 1. In addition to the silicon compounds, further hydrolysable compounds of aluminum, titanium, zirconium, vanadium, tin, lead and boron may be used. Particularly suitable catalysts for curing the compositions are tertiary amines which cause a crosslinking reaction of the epoxy groups at temperatures above 60 < 0 > C.

DE-OS 30 21 018 discloses a coating composition comprising a partially hydrolyzed condensate of an alkyl trialkoxysilane, an organic carboxylic acid and an anionic fluorocarbon surfactant. The silane used does not contain an epoxy group. This composition produces surface coatings having not only abrasion resistant surfaces but also excellent transparency, heat resistance, adhesion to substrate materials, and water resistance.

US-5 134 191 discloses a hard coating composition comprising an epoxy group-containing organosilicon compound and inorganic submicron particles, such as silica sol, which can be cured with a minimum amount of antimony compound as a curing catalyst. This composition can be used as a coating film for plastic optical products. In addition, the composition may optionally comprise an aluminum compound.

DE-OS 43 38 361 discloses coating compositions comprising oxides or hydroxides of Si, Al, B or transition metal nanoscale inclusive of epoxy group containing silicon compounds, particularly preferred boehmite, surfactants and aromatic polyols. In addition, the composition may comprise an alcoholate of a Lewis base, titanium, zirconium or aluminum.

It is an object of the present invention to provide compositions with improved hydrolytic stability, scratch resistance and UV stability.

The above-

(a) at least one silicon compound (A) containing at least one radical which is bonded directly to Si and which can not be cleaved by hydrolysis and contains an epoxy group,

(b) 0.5 to 15% by weight of particulate boehmite (B) in the particle size range of 1 to 100 nm,

(c) 5 to 30% by weight of granular cerium (C) particles having a particle size in the range of 1 to 100 nm,

(d) at least one hydrolysable silicon compound (D) and

(e) at least one hydrolyzable aluminum compound (E)

≪ / RTI >

In order to achieve hydrophilicity of the composition according to the present invention, Lewis base (F) may be further used as a catalyst.

In addition, a hydrolyzable silicon compound (G) having at least one non-hydrolyzable radical such as a dialkyldialkoxysilane, preferably dimethyldimethoxysilane, can be further used. Substituting a part of the silicon compound (D) with the silicon compound (G) can reduce the hardness of the resulting coating.

In order to achieve long-term hydrophilicity, the aromatic polyol (H) may be additionally used in order to add a non-ionic surfactant (G) and / or achieve corrosion inhibition (resistance to condensed water).

The compounds (A) to (H) are described in more detail below.

The silicon compound (A)

The silicon compound (A) is a silicon compound having 2 or 3, preferably 3 hydrolyzable radicals and 1 or 2, preferably 1 nonhydrolyzable radical. A single radical, or at least one of the two non-hydrolyzable radicals, has an epoxy group.

Examples of hydrolysable radicals are halogens (F, Cl, Br and I, especially Cl and Br), alkoxy (especially C _1-4 -alkoxy, such as methoxy, ethoxy, n-propoxy, isopropoxy and n- butoxy, tert-butoxy), aryloxy (especially C _{6-10 -aryloxy} , such as phenoxy), acyloxy (especially C _1-4 -acyloxy, For example acetoxy and propionyloxy) and alkylcarbonyl (for example acetyl). Particularly preferred hydrolysable radicals are alkoxy groups, especially methoxy and ethoxy.

Examples of non-hydrolyzable radicals having no epoxy group include hydrogen, alkyl, especially C _1-4 -alkyl (e.g. methyl, ethyl, propyl and butyl), alkenyl (C _2-4 -alkenyl, (Especially C _2-4 -alkynyl, such as acetylenyl and propargyl) and aryl (especially C _6-10 -aryl, such as, for example, 1-propenyl, 2- For example phenyl and naphthyl), and the abovementioned groups may optionally contain one or more substituents, for example halogen and alkoxy. Methacryl- and methacryloxy-propyl radicals may also be mentioned.

Examples of non-hydrolyzable radicals having epoxy groups are radicals, in particular those comprising glycidyl or glycidyloxy groups.

Specific examples of silicon compounds (A) which can be used in accordance with the invention can be found, for example, on pages 8 and 9 of EP-A-195 493, incorporated herein by reference.

A particularly preferred silicon compound (A) according to the present invention is a compound of the following formula:

R ₃ SiR '

(Preferably C _1-4 -alkoxy, in particular methoxy and ethoxy), and R 'represents a glycidyl or glycidyl group, Cydyloxy- (C _1-20 ) -alkylene radicals, in particular? -Glycidyloxyethyl-,? -Glycidyloxypropyl-,? -Glycidyloxybutyl-,? -Glycidyloxypentyl ω-glycidyloxydecyl-, ω-glycidyloxydodecyl-, ω-glycidyloxydecyl-, ω-glycidyloxydecyl-, ω-glycidyloxydecyl-, (3,4-epoxycyclohexyl) -ethyl.

In the present invention, it is particularly preferable to use γ-glycidyloxypropyltrimethoxysilane (hereinafter abbreviated as GPTS) which is easy to obtain.

The particulate boehmite (B)

The boehmite (B) in the granular phase is preferably used in a particle size in the range of 1 to 100 nm, preferably 2 to 50 nm, and particularly preferably 5 to 20 nm. This material can be used in powder form, but is preferably used in the form of a sol (especially an acid-stabilized sol). Particularly preferred is the use of nanoscale boehmite particles. The particulate boehmite can be purchased in powder form, and the process for preparing (acid-stabilized) sol from it is known in the prior art. In addition, the production examples described below can be referred to. Particular preference is given to using boehmite in the pH range of 2.5 to 3.5, preferably in the range of 2.8 to 3.2, for example by suspending the boehmite powder in dilute HCl.

The granular cerium oxide (C)

The granular cerium (C) is preferably used in a particle size in the range of 1 to 100 nm, preferably 2 to 50 nm, and particularly preferably 5 to 20 nm. This material can be used in powder form, but is preferably used in the form of a sol (especially an acid-stabilized sol). Granular cerium oxide can be purchased in the form of sol and powder, and the method of preparing the (acid-stabilized) sol from it is known in the prior art. In addition, the production examples described below can be referred to.

The hydrolyzable silicon compound (D)

In addition to the silicon compound (A), it is preferred that the hydrolyzable silicon compound is also used in the preparation of the composition according to the present invention and is hydrolyzed together with the silicon compound (A).

The hydrolyzable silicon compound (D) is a compound of the following formula:

R _x SiR ' _4-x

Wherein R represents a hydrolyzable radical, R 'represents a nonhydrolyzable radical, and x may be from 1 to 4. When more than one radical R and / or R 'is present in compound (D), these radicals may be the same or different. x is preferably greater than one. That is, the compound (D) has at least one, preferably at least two hydrolysable radicals.

Examples of hydrolysable radicals are halogens (F, Cl, Br and I, especially Cl and Br), alkoxy (especially C _1-4 -alkoxy, such as methoxy, ethoxy, n-propoxy, isopropoxy and n- butoxy, tert-butoxy), aryloxy (especially C _{6-10 -aryloxy} , such as phenoxy), acyloxy (especially C _1-4 -acyloxy, For example acetoxy and propionyloxy) and alkylcarbonyl (for example acetyl). Particularly preferred hydrolysable radicals are alkoxy groups, especially methoxy and ethoxy.

Examples of non-hydrolyzable radical is hydrogen, alkyl, especially C _1-4 - alkyl (e.g. methyl, ethyl, propyl, and n- butyl, isobutyl, sec- butyl and tert- butyl), alkenyl (especially C _{1 2} - alkenyl, such as vinyl, 1-propenyl, 2-propenyl and butenyl), alkynyl (especially C _2-4 - alkynyl, for example, acetyl alkylenyl and propargyl), and C _{6 -10} -aryl (e.g., phenyl and naphthyl), and the above-mentioned groups may optionally contain one or more substituents, such as halogen and alkoxy. Also, methacryl- and methacryloxy-propyl radicals can be mentioned.

Specific examples of the silicon compound (D) which can be used are as follows.

_{Si (OCH 3) 4, Si} (OC 2 H 5) 4, Si (On- or iso -C 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 , (iso-C 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 ) ₃ -COO-C ₃ H ₇ -Si (OCH ₃ ) ₃ ,

CH ₂ ═C (CH ₃ ) ₃ -COO-C ₃ H ₇ -Si (OC ₂ H ₅ ) ₃ .

The radicals R can be the same or different and are hydrolyzable groups, preferably alkoxy groups of 1 to 4 carbon atoms, in particular methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, is SiR ₄ compounds representing the sec- butoxy or tert- butoxycarbonyl is particularly preferred.

The hydrolyzable aluminum compound (E)

The compound (E) is preferably a compound of Al represented by the following formula.

Al (R '') ₃

In the above formula, the radicals R " " may be the same or different and represent a hydrolyzable group.

Examples of hydrolysable groups are halogens (F, Cl, Br and I, in particular Cl and Br), alkoxy (especially C _1-6 -alkoxy, such as methoxy, ethoxy, n-propoxy, isopropoxy and n- butoxy, tert-butoxy, n-pentyloxy, n-hexyloxy), aryloxy (especially C _{6-10 -aryloxy} , such as phenoxy), acyl aryloxy (especially C _1-4 - acyloxy, such as acetoxy and propionyloxy) and alkylcarbonyl (for example acetyl), or C _1-6 - alkoxy -C _2-3 - alkyl group, that is the C _1-6 -alkyl-ethylene glycol or -propylene glycol having the stated meaning, or a group derived from an alkoxy. R "is particularly preferably ethanolate, sec-butanolate, n-propanolate or n-butoxyethanolate.

Examples of the hydrolyzable aluminum compound (E) which can be used according to the invention _{Al (OCH 3) 3, Al} (OC 2 H 5) 3, Al (OnC 3 H 7) 3, Al (O- iso -C _{3 H 7) 3, Al (OC} 4 H 9) 3, Al (O- iso _{-C 4 H 9) 3, Al} (O-sec-C 4 H 9) 3, AlCl 3, AlCl (OH) 2, Al a _{(OC 2 H 4 OC 4 H} 9) 3.

Lewis base (F)

The Lewis base (F) is preferably a nitrogen compound. Such nitrogen compounds may be selected, for example, from N-heterocycles, amino group-containing phenols, polycyclic amines and ammonia (preferably in the form of aqueous solutions). Specific examples thereof 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 preferable.

Another class of nitrogen containing Lewis bases that can be used in accordance with the present invention is hydrolyzable silanes having at least one non-hydrolyzable radical comprising at least one primary, secondary or tertiary amino group. This silane can be hydrolyzed with the silicon compound (A), and then represents a Lewis base incorporated in an organically modified inorganic network. The nitrogen-containing silicon compound is preferably a compound represented by the following formula.

R ₃ SiR "

(Preferably C _1-4 -alkoxy and especially methoxy and ethoxy), R "is bonded to Si and is substituted by one or more of 1 Aminopropyltrimethoxysilane, N- (2-aminoethyl) silane, 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, Aminopropyltrimethoxysilane and N- [3- (triethoxysilyl) -3-aminopropyltrimethoxysilane, N- [N '- Propyl] -4,5-dihydroimidazole.

The Lewis base is usually used in the corresponding compositions at 0.01 to 0.5 moles per mole of epoxy group of the silicon compound (A). An amount of Lewis base per mole of epoxy group of 0.02 to 0.3 and especially 0.05 to 0.1 mole is preferable.

Surfactant (G)

The surfactant (G) which can be used for the purpose of achieving a long-term antifogging effect and increasing the hydrophilicity of the coating agent is preferably a nonionic surfactant. Particularly preferred are nonionic surfactants in liquid form at room temperature. These surfactants can be used not only in the preparation of the composition according to the method according to the present invention but also continuously (preferably in aqueous solution) by thermal diffusion at about 50 to 60 占 폚. Preferred surfactants are polyoxyethylene oleyl ethers of various chain lengths (e.g., Brij (R) 92,96 or 98, ICI), polyoxyethyl retecyl ethers of various chain lengths (e.g., Malipal (R) (E.g., 24/30 to 24/100, Huls and Disponil (R) 05, Henkel), sodium lauryl sulfate (e.g. Sulfopon TM 101 Spezial, Henkel), lauryl- Dehydquad C Christ < (R) >, Henkel) and polyoxyethylene-sorbitan monooleate (e.g. Tween, Riedel de Haen).

Surfactants are typically used in amounts of from 0.1 to 35% by weight, based on the coating composition.

The aromatic polyol (H)

The aromatic polyol used according to the present invention has an average molecular weight of 1000 or less. Examples of such polyols include not only polyphenylene ethers having a hydroxy group on two or more phenyl rings but also aromatic polyphenylene ethers having aromatic rings bonded to each other by a single bond, -O-, -CO-, -SO ₂ - Preferably an oligomer having two or more hydroxy groups.

Particularly preferred aromatic polyols are aromatic diols. Particularly preferred among these are compounds of the formula:

X is a (C ₁ -C ₈ ) -alkylene or -alkylidene radical, a (C ₆ -C ₁₄ ) -arylene radical, -O-, -S-, -CO- or -SO ₂ - , And n is 0 or 1. X is preferably C ₁ -C ₄ -alkylene or -alkylidene, especially -C (CH ₃ ) ₂ - and -SO ₂ -. The aromatic ring of the compound may contain up to three or four additional substituents, such as halogen, alkyl and alkoxy, outside the OH moiety.

Specific examples of the aromatic polyol (H) which can be used in accordance with the present invention are bisphenol A, bisphenol S and 1,5-dihydroxynaphthalene, and bisphenol A is preferred.

The polyol (H) is usually used in an amount such that 0.2 to 1.5 mol, preferably 0.3 to 1.2 mol, especially 0.6 to 1.0 mol, of the hydroxyl group of the aromatic polyol (H) per 1 mol of the epoxy ring of the silicon compound (A) .

When the silicone compound (A) having two or more epoxy groups is used in the composition according to the present invention, the stability against the condensation water of the coating agent and the molded article is improved.

The composition according to the invention is preferably obtained by the process described in more detail below, in which a sol of the substance (B) having a pH range of from 2.5 to 3.5, preferably from 2.8 to 3.2, Respectively.

More preferably, the composition according to the invention is obtained by a process as defined below, wherein preferably at a specific temperature, the mixture of (A) and (D) And the addition of (E) is also carried out between two additions of (B) at a certain temperature.

The hydrolyzable silicon compound (A) can be prehydrolyzed with the compound (D) using an acid catalyst (preferably at room temperature) in an aqueous solution. At this time, it is preferable to use about 1/2 mol of water per mol of the hydrolyzable group. It is preferable that hydrochloric acid is used as the preliminary moisture-decomposing catalyst.

It is preferred that the particulate boehmite (B) is suspended in water and the pH is adjusted to 2.5 to 3, preferably 2.8 to 3.2. It is preferable to use hydrochloric acid for acidification. Under this condition, a transparent sol is formed.

Compound (D) is mixed with compound (A). A single portion of the suspended particulate boehmite (B) as described above is then added. This amount is preferably selected to a degree sufficient for the water contained in the mixture to be half-stoichiometric hydrolysis of compounds (A) and (D).

After several minutes after the addition, the sol is warmed to about 28-35 占 폚 and becomes clear after about 20 minutes. Then, the mixture is stirred for 0.5 to 3 hours, preferably 1 to 2 hours. The batch is cooled to about 0 < 0 > C. Then, the compound (E) is added, and the temperature of about 3 캜 is not exceeded. When the addition of the compound (E) is completed, the sol is stirred at 0 캜 for 0.5 to 3 hours, preferably for 1 to 2 hours. Subsequently, the residual amount of the granular substance (B) is added, and the temperature of 5 占 폚 is not exceeded in the meantime. The reactor temperature is then adjusted to 20 DEG C to bring the composition to room temperature. It is understood that the room temperature is a temperature of 20 to 23 캜. Compound (C) is added to stabilize the scratch resistant coating system against UV. The compound (C) is preferably in the form of a sol. The composition is stored in a refrigerator at 4 ° C.

Compound (E) and, optionally, Lewis base (F) are preferably added slowly at 0 캜 after the addition of a single portion of the substance (B).

To adjust the rheological properties of the composition, an inert solvent may optionally be added at any desired stage of preparation. Such solvents are preferably alcohols which are liquid at room temperature, and more preferred are alcohols formed during hydrolysis of the alkoxide. Particularly preferred alcohols are C _1-8 -alcohols, in particular methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n- pentanol, isopentanol, And n-butoxyethanol. In addition, C _1-6 -glycol ethers, especially n-butoxyethanol, are preferred.

The compositions according to the invention may also comprise customary additives such as colorants, flow agents, UV stabilizers, photoinitiators, photosensitizers (if photochemical curing of the composition is desired) and thermal polymerization catalysts.

The coating method of the substrate is carried out by standard coating methods such as immersion, painting, brushing, blade coating, roll coating, spraying, drop film coating, centrifugal coating and spin coating.

Curing of the coated substrate is optionally performed after partial drying first at room temperature. The curing is carried out in a thermal manner under reduced pressure, optionally at 50 to 300 ° C, in particular at 70 to 200 ° C and particularly preferably at 90 to 180 ° C. The time required to fully cure under these conditions should be less than 200 minutes, preferably less than 100 minutes and more preferably less than 60 minutes. The layer thickness of the cured layer should be from 0.5 to 100 mu m, preferably from 1 to 20 mu m and especially from 2 to 10 mu m.

If unsaturated compounds and photoinitiators are present, they can also be cured after irradiation and, optionally, postcured by a thermal method.

There is no restriction on the selection of the substrate material for coating. The coating compositions according to the present invention are preferably suitable for coating of wood, textile, paper, stone, metal, glass, ceramic and plastic and are particularly suitable for coating in the context of Becker / Braun, Kunststofftaschenbuch, Carl Hanser Verlag, Munich, Vienna 1992 And is suitable for coating thermoplastic materials as described. The composition is well suited for coating transparent thermoplastic materials and preferably polycarbonate, or for coating metal or metallized surfaces. The spectacle lens, the optical lens, the automobile window, and especially the thermal recording head obtained according to the present invention can be coated.

Example

Preparation of a boehmite dispersion

To prepare a boehmite dispersion, 0.1 N hydrochloric acid was placed in a vessel. The boehmite was then slowly added with stirring. The dispersion was then treated with ultrasonic waves for about 20 minutes.

Manufacture of scratch resistant coating systems

GPTS and TEOS were placed in a container and mixed. The amount of boehmite dispersion needed for half-stoichiometric prehydrolysis of silane was slowly added with stirring. The reaction mixture was then stirred at room temperature for 2 hours. The solution was then cooled to 0 < 0 > C using a thermostat. Subsequently, aluminum tributoxyethanolate was added dropwise using a dropping funnel. Aluminate was added, and the mixture was further stirred at 0 ° C for 1 hour. The remainder of the boehmite dispersion was then added while cooling by a thermostat. After stirring at room temperature for 15 minutes, a cerium dioxide dispersion and a flow agent were added.

Starting content

Example 21 Example 23 Example 25 TEOS - 62.50 g (0.3 mol) 62.50 g (0.3 mol) DMDMS 36.09 g (0.3 mol) - 36.09 g (0.3 mol) GPTS 236.34 g (1 mole) 236.34 g (1 mole) 236.34 g (1 mole) Bohemite 5.47 g (2% by weight based on total solids) 5.53 g (2% by weight based on total solids) 6.14 g (2% by weight based on total solids) 0.1 N hydrochloric acid 48.97 g 59.18 g 74.21 g A cerium dioxide dispersion (20% by weight in 2.5% acetic acid) 222.60 g (17.5% by weight based on total solids) 257.14 g (20% by weight based on total solids) 285.66 g (20% by weight based on total solids) Boehmite dispersion for half-stoichiometric preliminary hydrolysis 36.06 g 41.38 g 46.83 g Aluminum tributoxyethanolate 113.57 g (0.3 mol) 113.57 g (0.3 mol) 113.57 g (0.3 mol) Fluidizing agent 2.00 g (0.3% by weight based on the total coating amount) 2.21 g (0.3% by weight based on the total coating amount) 2.45 g (0.3% by weight based on the total coating amount)

Further examples and comparative examples were carried out according to the above method and the amounts of the components were varied according to the values given in Table 1.

Test specimens were obtained as follows using the resulting coatings.

A polycarbonate plate (Tg = 147 ° C, Mw = 27,500) of 105 × 150 × 4 mm in size was washed with isopropane and immersed in a mixture of 3% by weight of aminopropyltrimethoxysilane and 97% by weight of butanol And then heat-treated at 130 ° C for 0.5 hour. Each plate was then coated with a coating layer having a thickness of 10 to 20 mu m at a deposition rate (V) of 60 to 100 cm / min. After cooling at room temperature for 10 minutes, the coated plate was dried at 130 DEG C for 1 hour. The layer thickness of the coating layer after drying was about 2 to 4 mu m. Once the coated plates were fully cured, they were stored at room temperature for 2 days and then tested as defined below.

The properties of the coatings obtained using the coating compositions were determined as follows.

Cross-cut adhesion test: EN ISO 2409: 1994

Cross-cut adhesion test after storage in water: 65 ° C tt = 0/1. Coated plates were cut in accordance with EN ISO 2409: 1994 and stored in water at 65 ° C. The storage time (days) in which the adhesive was first lost in the tape test was recorded as 0 to 1.

Taber Magma test: Abrasion test DIN 52 347 (10,000 times, CS10F, 500 g)

Weather test (Sun test):

The coated sample (using Makrolon 2808 as substrate) was placed in a weather test accelerator (sun test, Heraeus CPS type) equipped with a quartz glass filter for 3 weeks at full power. After 1, 2 and 3 weeks, the ecliptic was measured by a UV-VIS analyzer (parameter: standard light C, 2 ° standard observer). In addition, samples were visually measured (crack formation, etc.).

Underwater storage test:

A glass desiccator filled with deionized water was placed in a drying cabinet at about 65 ° C. The coated polycarbonate sample, which had been pre-cross-cut / tape tested after curing, was placed in a dryer. After 2, 4, 6, 8, 10, 12 and 14 days, the samples were tested for adhesion by crosscut / tape test. Finally, in each case a first crosscut test was performed and a completely new crosscut / tape test was performed. In addition, samples were visually evaluated (crack formation, separation, etc.).

Boiling test:

In this test, a Schott flask filled with deionized water was used. The vessel was insulated with a polystyrene jacket and boiled using a magnetic heating stirrer (temperature of about 97 ° C). A sample (coated polycarbonate) previously subjected to a cross-cut / tape test was placed. After 1, 2, 3, 4, 5, 6, 7 and 8 hours, the plates were removed and evaluated for appearance (cracking, separation, etc.). In addition, the adhesiveness was tested for both the first cross-cut and the newly prepared cross-cut.

Layer thickness measurement:

The layer thickness was measured by a profiled method using fine diamond needles directed onto the surface. For the measurement, a portion of the plate must be removed during coating to determine the difference in height between the uncoated and coated areas.

Claims (8)

(a) at least one silicon compound (A) containing at least one radical which is bonded directly to Si and which can not be cleaved by hydrolysis and contains an epoxy group, (b) 0.5 to 15% by weight of particulate boehmite (B) in the particle size range of 1 to 100 nm, (c) 5 to 30% by weight of granular cerium (C) particles having a particle size in the range of 1 to 100 nm, (d) at least one hydrolysable silicon compound (D) and (e) at least one hydrolyzable aluminum compound (E) ≪ / RTI > The positive resist composition according to claim 1, wherein (A) R ₃ SiR ' Wherein the radicals R are the same or different and represent hydrolysable groups, preferably C _1-4 -alkoxy and R 'is a glycidyl- or glycidyloxy- (C _1-20 ) -alkylene radical ), ≪ / RTI > (D) is represented by the following formula SiR ₄ (Wherein the radicals R are the same or different and represent a hydrolyzable group, preferably C _1-4 -alkoxy) (E) is represented by the following formula AlR ₃ (Wherein the radicals R are the same or different and represent a hydrolyzable group, preferably a C _1-6 -alkoxy, a C _1-6 -alkoxypropanolate group or a C _1-6 -alkoxyethanolate group) . According to claim 1 or 2, wherein, (A) the γ- glycidyloxy propyl silane, and, (D) is tetraethoxysilane, and (E) an Al (butoxyethanol rate) to ₃ or compositions. The silicon compound (A) and the compound (D) are first mixed a) a batch of 10 to 70% by weight of the total amount of the sol of the substance (B) having a pH of 2.5 to 3.5 is added, b) Compound (E) is added followed by c) two doses of the sol of the substance (B), and finally d) cerium oxide (C) and e) any flow agent and inert solvent ≪ / RTI > is added to the composition. The process according to any one of claims 1 to 3, wherein the addition in step a) is carried out at a temperature above 25 ° C and the addition in step b) and step c) is carried out at 0 ± 2 ° C. Use of a composition according to any one of claims 1 to 5 in the coating of a substrate material of any kind, preferably a thermoplastic, particularly preferably a polycarbonate. The composition of claim 6, wherein the composition optionally comprises an inert solvent, preferably a C _1-8 -alcohol and / or a monoalkyl glycol ether, especially n-butoxyethanol, to adjust the rheological properties, (A) thermally curing at a temperature of preferably 90 to 180 ° C, or (b) pre-curing the photoinitiator after the photoinitiator has been added in advance and optionally postcuring it in a thermal manner. A product coated with the composition obtained according to any one of claims 1 to 5.