HK1172869A - Combination of two triazine uv absorbers for coating on polycarbonate - Google Patents

Description

Combination of two triazine UV absorbers for lacquers on polycarbonate

The invention relates to a multilayer product comprising at least a first, a second and a third layer, wherein the first layer contains polycarbonate, the second layer is a UV protective layer based on alkyl acrylates containing two triazine compounds as UV stabilizers, and the third layer is a scratch-resistant layer which also contains a UV absorber. The invention also relates to the production of such a multilayer product and to moulded bodies (Formk headphones), such as window panes (Verscheibung) containing the multilayer product.

Shaped bodies of polycarbonate have been known for a long time. However, polycarbonates have the disadvantage of being inherently UV-unstable. The sensitivity curve for bisphenol A polycarbonate has the highest sensitivity between 320 nm and 330 nm. Below 330 nm, no solar radiation reaches the earth, and above 350 nm, polycarbonate is so insensitive that yellowing no longer occurs.

In order to protect polycarbonates from the harmful effects of UV radiation in the air, UV stabilizers are generally used which absorb UV radiation and convert it into harmless thermal energy.

For long-lasting protection, it is advantageous if it is possible to filter harmful UV radiation effectively before it has reached the polycarbonate surface, by using a UV protective layer on the polycarbonate, for example a coextruded layer containing a UV absorber, a film containing a UV absorber or a lacquer containing a UV absorber.

Typical classes of UV absorbers known to be useful for this purpose are compounds of the 2-hydroxy-benzophenone type, compounds of the 2- (2-hydroxyphenyl) benzotriazole type, compounds of the 2- (2-hydroxyphenyl) -1,3, 5-triazine type, compounds of the 2-cyanoacrylate type and compounds of the oxanilide type (Oxalanilide).

For outdoor applications, improved scratch protection is also necessary in most cases. This can be achieved by applying a scratch resistant paint. The prior art today for this purpose is sol-gel silicate lacquers (see, for example, EP-A0339257, US-A5,041,313) and other inorganic hybrid lacquers (hybrid lack) (EP-A0570165). The combination of properties of the organosilane based lacquer further includes excellent weather and light stability, as well as heat, alkali, solvent and moisture resistance.

Triazine-based UV absorbers show the highest stability in PMMA and UV curable acrylate lacquers compared to other UV absorbers. The stability can be further improved by the addition of HALS systems (hindered amine light stabilizers) (J.Pospisil et al, prog.Polym.Sci.25 (2000) 1261-1335).

EP-A1308084 generally discloses triazine-based UV absorbers and benzotriazole-based UV absorbers, optionally in combination with HALS. A large number of possible applications for a large number of UV absorber variants are disclosed, in particular also the use in coatings. The use of the claimed UV absorber combination in polycarbonates or in coating compositions is not specifically described. Any combination of the lists described in EP-a 1308084, or even the combinations of UV absorbers mentioned as preferred or in the examples, does not indicate that the UV absorbers have to be selected in order to provide the best protection against weathering (betwitterung) for a multilayer structure of polycarbonate-UV protective layer-scratch resistant coating.

EP-A0502816 describes the use of phenyl-or p-tolyl-substituted triazines in combination with HALS in lacquer systems, for example as protective top coats for automobiles.

WO 00/66675 a discloses the use of biphenyl-substituted triazines in the form of mixtures also in combination with HALS in adhesives.

WO 2008/107095 a discloses polycarbonate compositions containing a mixture of biphenyl substituted triazine derivatives and another UV absorber in a specific quantitative ratio. It is therefore a UV-protected and unpainted polycarbonate.

WO 2006/108520 a describes the use of biphenyl substituted triazines of formula I in PMMA UV protective layers for polycarbonates. It is essential to mention in the application that the initial degree of extinction during weathering is high and that the decomposition of the UV absorber is low.

However, the above-mentioned applications do not contain any teaching as to the selection of particularly effective UV absorber combinations in a multilayer system consisting of polycarbonate layer, UV protective layer and scratch-resistant lacquer.

The UV-stabilized polycarbonate moldings known from the prior art still exhibit unsatisfactory long-term stability with respect to yellowing and clouding in many applications, in particular in outdoor applications, in which high requirements have to be met in respect of scratch resistance and a long-lasting, excellent visual perception, for example in window panes.

For most applications, polycarbonate moldings must be at 9 MJ/m²As low as possible, a radiation of 340 nm (corresponding to 3 years outdoor weathering in florida) showed yellowing and cloudiness.

In an Atlas Ci 5000 weatherometer, 0.75W/m at 340 nm is used²And over a total time of 3000 hours was 102: 18 minutes drying/rain cycle (equivalent to 8.1 MJ/m at 340 nm)²) Wind erosion was performed in this test. The blackboard temperature was 70 ℃, the sample chamber temperature was 55 ℃, and the atmospheric humidity was 40%.

The object of the present invention was to provide scratch-resistant polycarbonate moulded bodies which are 9 MJ/m at 340 nm under the stated conditions²As low as possible a rehmannia change and a cloudiness under irradiation.

It has now surprisingly been found that multilayer structures comprising specific combinations of UV absorbers are significantly superior to those according to the prior art in the form of so-called equivalent combinations with respect to these requirements. The invention therefore provides a multilayer product comprising at least one first layer (a), a second layer (B) and a third layer (C), wherein the first layer (a) comprises polycarbonate, the second layer (B) is a UV protective layer comprising a polyalkyl (meth) acrylate of a UV stabilizer combination of the formulae (I) and (II), and the third layer (C) is a UV-protected scratch-resistant layer.

The multilayer product of the invention may comprise further layers, in particular a further UV protective layer (D), which is likewise an alkyl acrylate layer and in each case comprises at least one UV stabilizer, for example selected from the abovementioned UV absorber classes, for example 2-hydroxy-benzophenones, 2- (2-hydroxyphenyl) benzotriazoles, 2- (2-hydroxyphenyl) -1,3, 5-triazines, 2-cyanoacrylates and oxalanilides, the preferred triazine derivatives being UV absorbers according to formulae (I) and (II), and a further scratch-resistant layer (E). In this case, the sequence of layers is (C) - (B) - (A) - (D) - (E), and layers (B) and (D) and (C) and (E) may have the same or different compositions. Another possible variant is to apply only a scratch-resistant layer containing a UV absorber on the inside, since there is little UV protection requirement. The sequence of layers is thus (C) - (B) - (A) - (E).

The article may further comprise other coatings. In addition to the coatings (B), (C), (D), (E), the presence of further coatings (F) is contemplated, for example IR-absorbing layers, IR-reflecting layers, electrically conductive layers, electroluminescent layers, colouring and printing layers for decorative purposes, electrically conductive printing layers as for example for vehicle window heating, optionally also layers comprising electrically heated wires, anti-reflection layers, no-drip coatings, anti-fog coatings, anti-fingerprint coatings and/or combinations thereof. Such layers may be applied or present in the form of intermediate layers and/or internal cover layers.

The at least one UV absorber used in layer (B) and optionally (D) of the multilayer product according to the invention has the general formula (I)

(I)

Wherein X represents OR¹；OCH₂CH₂OR¹；OCH₂CH(OH)CH₂OR¹Or OCH (R)²)COOR³Wherein R is¹In each case representing a branched or unbranched C₁-C₁₃Alkyl radical, C₂-C₂₀-alkenyl, C₆-C₁₂Aryl or CO-C₁-C₁₈-an alkyl group; r²Is H or branched or unbranched C₁-C₈-an alkyl group; and R³Is represented by C₁-C₁₂-an alkyl group; c₂-C₁₂-alkenyl or C₅-C₆-a cycloalkyl group.

X is preferably OCH (R)²)COOR³(ii) a Particularly preferred is the compound wherein R² = CH₃And R³ = C₈H₁₇。

The at least one UV absorber used in layer (B) and optionally (D) of the multilayer product of the invention has the general formula (II)

(II)

Wherein T is¹Is C₁-C₁₈-alkyl or C₄-C₁₈-alkyl interrupted by COO or OCO or O, or interrupted by O and substituted by OH.

T¹Preferably C₁-C₁₈Alkyl and particularly preferably C₈H₁₇。

Such biphenyl-substituted and phenyl-substituted triazines of the general formulae I and II are in principle described in WO 96/28431A, DE-A1973997; WO 00/66675A; US-a 6225384; US-a 6255483; EP-A1308084 and FR-A2812299 are known.

The UV protective layers (B) and (D) of the present invention may comprise other UV absorbers, preferably selected from the group consisting of 2-hydroxy-benzophenone-based compounds, 2- (2-hydroxy-phenyl) benzotriazole-based compounds, 2- (2-hydroxyphenyl) -1,3, 5-triazine-based compounds, 2-cyanoacrylate-based compounds and oxalic anilide-based compounds.

The UV protective layers (B) and (D) according to the invention can be cured lacquer formulations, film layers or coextruded layers.

The UV protective layers (B) and (D) according to the invention of the cured lacquer formulations comprise, as binder material, a physically drying polyacrylate resin which comprises methyl methacrylate as main component and may have longer linear or branched alkyl chains (-C)_nH_2n+1Where n > 1), preferably 1. ltoreq. n.ltoreq.10, particularly preferably a linear alkyl chain in which n = 3 (butyl methacrylate)An outer alkyl methacrylate. The ratio of the two methacrylate units is 75 to 100% methyl methacrylate and 25 to 0% alkyl methacrylate, preferably 85 to 100% methyl methacrylate and 15% to 0% alkyl methacrylate, particularly preferably 90 to 100% methyl methacrylate and 10% to 0% alkyl methacrylate.

The UV protective layers (B) and (D) according to the invention in the form of films and coextruded layers comprise, as polymer matrix, polyacrylates composed of alkyl methacrylates, preferably having an alkyl chain length (-C) of less than 10 carbon atoms_nH_2n+1Where n < 10), alkyl chain lengths (methyl methacrylate) with n = 1 are particularly preferred.

Since a certain minimum degree of extinction of the UV protective layer is necessary for durable UV protection, the required UV absorber concentration depends on the layer thickness.

The UV absorbers of formulae (I) and (II) in layer (B) are present at 9.9: 0.1 to 6.1: 3.9, preferably 9: 1 to 7: 3, particularly preferably 8.5: 1.5 to 7.5: 2.5 UV absorbers of the formula (I): the ratio of the UV absorbers of the formula (II) is used.

The UV protective layers according to the invention obtained from cured lacquer formulations comprise, for a layer thickness of 1 to 100. mu.m, preferably 1 to 30 μm, particularly preferably 1 to 10 μm, from 0.5 to 20% by weight, preferably 1 to 15% by weight, particularly preferably 1.5 to 10% by weight, based on the solids content of the lacquer formulation, of a mixture of UV absorbers of the formulae (I) and (II) in the mixing ratios described above, wherein formulations having a layer thickness of 1 μm after application and curing comprise at least 10% by weight, preferably ≧ 15% by weight, those of 5 μm comprise at least 2% by weight, preferably ≧ 3% by weight, and those of 10 μm comprise at least 1% by weight, preferably ≧ 1.5% by weight.

The UV protective layer according to the invention derived from the coextruded layer comprises from 0.05 to 20% by weight, preferably from 0.1 to 15% by weight, particularly preferably from 0.5 to 10% by weight, of the UV absorber mixture of the formulae (I) and (II) in the abovementioned mixing ratio, for a layer thickness of from 1 to 500. mu.m, preferably from 1 to 100. mu.m, particularly preferably from 2 to 50 μm, where the coextruded layer having a layer thickness of 2 μm comprises at least 10% by weight, preferably ≧ 15% by weight, those of 10 μm comprise at least 2% by weight, preferably ≧ 3% by weight, and those of 30 μm comprise at least 0.7% by weight, preferably ≧ 1% by weight. The weight percentages are based on the total weight of layer (B).

The UV protective layer according to the invention derived from the film comprises from 0.01 to 20% by weight, preferably from 0.02 to 5% by weight, particularly preferably from 0.04 to 2% by weight, of the UV absorber mixture of the formulae (I) and (II) in the abovementioned mixing ratios, for a layer thickness of from 2 μm to 2 mm, preferably from 50 μm to 1 mm, particularly preferably from 80 μm to 500 μm, wherein the film having a layer thickness of 80 μm comprises at least 0.25% by weight, preferably ≥ 0.4% by weight, those of 200 μm comprise at least 0.1% by weight, preferably ≥ 0.15% by weight, and those of 500 μm comprise at least 0.04% by weight, preferably ≥ 0.06% by weight. The weight percentages are based on the total weight of layer (B).

Further stabilization of the UV protective layer can be achieved by using a so-called HALS system (hindered amine light stabilizer) of the general formula (IIIa) in addition to the triazine, i.e. the actual UV absorber

(IIIa)

Wherein Y represents H, R¹OR OR¹And R¹C in each case branched or unbranched₁-C₁₃Alkyl radical, C₂-C₂₀-alkenyl, C₆-C₁₂-aryl or-CO-C₁-C₁₈-alkyl, R²Is H or branched or unbranched C₁-C₈-alkyl, and R³Is represented by C₁-C₁₂-an alkyl group; c₂-C₁₂-alkenyl or C₅-C₆-a cycloalkyl group.

R⁴ByZ-R⁵-Z-R⁶Composition is carried out; in particular

Or

So as to obtain the following formula

(IIIb)，

(IIIc)，

(IIId)，

Wherein

ZIs a divalent functional group, e.g.COO、NHOrCONH，

R⁵Is a divalent organic residue, e.g.CH₂Wherein n = 0 to 12, or: c = CH-Ph-OCH₃，

Or，

R⁶Is H or C₁-C₂₀-an alkyl group.

For a UV protective layer from a cured paint formulation, Y = R is preferred¹And are and

R⁴ = ，

y = R is particularly preferred¹Wherein R is¹ = C₁-C₁₃-alkyl, and

R⁴ = 。

this gives rise to the preferred compounds of the general formula (IIIe) of the following group.

(IIIe)。

The inventive UV protective layer from the cured lacquer formulation comprises from 0 to 5% by weight, preferably from 0 to 3% by weight, particularly preferably from 0.5 to 2% by weight, of the compound of the formula (III), based on the solids content of the lacquer formulation. When particularly preferred amounts of the particularly preferred HALS system (IIIe) are used, the necessary amount of UV absorber mixture of (I) and (II) is reduced to preferably ≥ 10% by weight for a layer thickness of 1 μm after application and curing, preferably ≥ 2% by weight for 5 μm and ≥ 1% by weight for 10 μm.

In the case of UV protective layers from coextruded layers and from films, it is also possible to use HALS systems in amounts of from 0 to 3% by weight. However, owing to the higher processing temperatures, higher molecular weight HALS systems are preferred here in which more than twice the functional group (IIIf) contained in formula IIIa is present per molecule

(IIIf)。

Particular preference is given to high molecular weight HALS systems having a weight loss at 300 ℃ of 3% by weight, determined by TGA at a heating rate of 20 ℃ per minute in air, such as the compounds of the formula (IIIg) available as Chimassorb 119 from Ciba,

(IIIg)。

suitable polycarbonates for the layer (A) of the multilayer product according to the invention are all known polycarbonates; they may be homopolycarbonates, copolycarbonates and thermoplastic polyester carbonates.

They have an average molecular weight of preferably from 18,000 to 40,000, preferably from 22,000 to 36,000, and in particular from 24,000 to 33,000_wDetermined by light scattering calibration by measuring the relative solution viscosity in dichloromethane or in an equal part by weight mixture of phenol/o-dichlorobenzene.

For the preparation of Polycarbonates, reference may be made, for example, to "Schnell, Chemistry and Physics of Polycarbonates, Polymer Reviews, volume 9, Interscience Publishers, New York, London, Sydney 1964", and "D.C.PREVORSEK, B.T.DEBONA and Y.KESTEN, Corporation Research Center, Allied Chemical Corporation, Moristown, New Jersey 07960, 'Synthesis of Poly (ester) carbonate Copolymers', Journal of Polymer Science, Polymer Chemistry Edition, volume 19, volume 75-90 (1980)", and "D.initag, U.G., G.P.M. also, N.Noutverne, BAR AG ', Encyclopedia of cellulose, cell Corporation, cell 1980", and "D.S. Pat. No. 2, U.G, P.M. N.N.Noutverne, cell AG', cell Corporation, cell III, cell 3/1, cell K, cell 1988, cell pages 11, cell handbook, cell 21, cell III, cell.

The preparation of the polycarbonates is preferably carried out by the phase interface process or the melt transesterification process, and is described below by way of example according to the phase interface process.

Preferred compounds for use as starting compounds are bisphenols of the general formula

HO-R⁷-OH，

Wherein R is⁷Is a divalent organic residue containing one or more aromatic groups having 6 to 30 carbon atoms.

Examples of such compounds are bisphenols belonging to the following group: dihydroxydiphenyl, bis (hydroxyphenyl) alkane, indane bisphenol, bis (hydroxyphenyl) ether, bis (hydroxyphenyl) sulfone, bis (hydroxyphenyl) ketone and α, α' -bis (hydroxyphenyl) -diisopropylbenzene.

Particularly preferred diphenols belonging to the above-mentioned group of compounds are bisphenol A, tetraalkylbisphenol A, 4- (M-phenylenediisopropyl) diphenol (bisphenol M), 4- (p-phenylenediisopropyl) diphenol, 1-bis- (4-hydroxyphenyl) -3,3, 5-trimethylcyclohexane (BP-TMC) and optionally mixtures thereof.

The bisphenol compounds used according to the invention are preferably reacted with carbonic acid compounds, in particular phosgene, or, in the melt transesterification process, diphenyl carbonate or dimethyl carbonate.

The polyester carbonates are preferably obtained by reacting the already mentioned bisphenols, at least one aromatic dicarboxylic acid and optionally carbonic acid equivalents. Suitable aromatic dicarboxylic acids are, for example, phthalic acid, terephthalic acid, isophthalic acid, 3 '-or 4,4' -biphenyldicarboxylic acid and benzophenonedicarboxylic acid. Some, up to 80 mol%, preferably from 20 to 50 mol%, of the carbonate groups in the polycarbonates may be substituted by aromatic dicarboxylic acid ester groups.

Inert organic solvents used in the interfacial polymerization are, for example, dichloromethane, various dichloroethane and chloropropane compounds, tetrachloromethane, trichloromethane, chlorobenzene and chlorotoluene; chlorobenzene or dichloromethane, or mixtures of dichloromethane and chlorobenzene are preferably used.

The phase interface reaction can be carried out, for example, with tertiary amines, in particular N-alkanesRadical piperidine orCatalyst promotion of salts. Tributylamine, triethylamine and N-ethylpiperidine are preferably used. In the case of the melt transesterification process, the catalysts mentioned in DE-A4238123 are preferably used.

The polycarbonates may be linear or branched. Mixtures of branched and unbranched polycarbonates may also be used.

The polycarbonates may be branched in a deliberate and controlled manner by using small amounts of branching agents. Some suitable branching agents are phloroglucinol, 4, 6-dimethyl-2, 4, 6-tris- (4-hydroxyphenyl) -hept-2-ene; 4, 6-dimethyl-2, 4, 6-tris- (4-hydroxyphenyl) -heptane; 1,3, 5-tris- (4-hydroxyphenyl) -benzene; 1,1, 1-tris- (4-hydroxyphenyl) -ethane; tris- (4-hydroxyphenyl) -phenylmethane; 2, 2-bis- [4, 4-bis- (4-hydroxyphenyl) -cyclohexyl ] -propane; 2, 4-bis- (4-hydroxyphenylisopropyl) -phenol; 2, 6-bis- (2-hydroxy-5' -methyl-benzyl) -4-methylphenol; 2- (4-hydroxyphenyl) -2- (2, 4-dihydroxyphenyl) -propane; hexa- (4- (4-hydroxyphenylisopropyl) -phenyl) -orthoterephthalate; tetrakis- (4-hydroxyphenyl) -methane; tetrakis- (4- (4-hydroxyphenylisopropyl) -phenoxy) -methane; α, α, 'α' -tris- (4-hydroxyphenyl) -1,3, 5-triisopropylbenzene; 2, 4-dihydroxybenzoic acid; trimesic acid; cyanuric chloride; 3, 3-bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2, 3-indoline; 1, 4-bis- (4',4 "-dihydroxytriphenyl) -methyl) -benzene and in particular: 1,1, 1-tris- (4-hydroxyphenyl) -ethane and bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2, 3-indoline.

Branching agents or branching agent mixtures, optionally used together in amounts of from 0.05 to 2 mol%, based on the diphenols used, may be used together with the diphenols or may additionally be added at a later stage of the synthesis.

Suitable branching agents for polycarbonates are known from the literature and are described, for example, in the patent documents U.S. Pat. No. 4, 4185009, DE-A2500092, DE-A4240313, DE-A19943642, U.S. Pat. No. 3, 5367044 and the documents cited therein. In addition, the polycarbonates used may also be intrinsically branched, in which case no branching agents are added in the context of the preparation of the polycarbonates. An example of intrinsic branching is the so-called Fries structure, as disclosed in EP-A1506249 for melt polycarbonates.

As chain terminators, preference is given to using from 1 to 20 mol%, preferably from 2 to 10 mol%, of phenols, such as phenol, alkylphenols, such as cresol and 4-tert-butylphenol, chlorophenol, bromophenol, cumylphenol or mixtures thereof, per mole of bisphenol. Phenol, 4-tert-butylphenol and cumylphenol are preferred.

Chain terminators and branching agents may be added to the synthesis either separately or together with the bisphenols.

According to the invention, the polycarbonates preferably used for layer A of the multilayer product according to the invention are homopolycarbonates based on bisphenol A, homopolycarbonates based on 1, 1-bis- (4-hydroxyphenyl) -3,3, 5-trimethylcyclohexane and copolycarbonates based on the two monomers bisphenol A and 1, 1-bis- (4-hydroxyphenyl) -3,3, 5-trimethylcyclohexane.

Homopolycarbonates based on bisphenol a are particularly preferred.

The polycarbonate may comprise a stabilizer. Suitable stabilizers are, for example, phosphines, phosphites or Si-containing stabilizers and also other compounds described in EP-A0500496. Examples which may be mentioned are triphenyl phosphite, diphenylalkyl phosphites, phenyldialkyl phosphites, tris- (nonylphenyl) phosphite, tetrakis (2, 4-di-tert-butylphenyl) -4,4' -biphenylene diphosphonite and triaryl phosphites. Triphenylphosphine and tris- (2, 4-di-tert-butylphenyl) phosphite are particularly preferred.

The polycarbonate-containing layer (A) of the multilayer product according to the invention may further comprise from 0.01 to 0.5% by weight of esters or partial esters of mono-to hexahydric alcohols, in particular of glycerol, pentaerythritol or Guerbet alcohols.

Monohydric alcohols are, for example, stearyl alcohol, palmityl alcohol and Guerbet alcohol.

The diol is, for example, ethylene glycol.

The trihydric alcohol is, for example, glycerol.

Tetrahydric alcohols are, for example, pentaerythritol and mesoerythritol.

Pentahydric alcohols are, for example, arabitol, ribitol and xylitol.

Hexahydric alcohols are, for example, mannitol, sorbitol (sorbitol) and dulcitol.

The ester is preferably a saturated aliphatic C₁₀-to C₃₆Monocarboxylic acids and optionally hydroxy-monocarboxylic acids, preferably with saturated aliphatic C₁₄-to C₃₂Mono-, di-, tri-, tetra-, penta-, and hexa-esters of monocarboxylic acids and optionally hydroxy-monocarboxylic acids or mixtures thereof, especially random mixtures.

Commercially available fatty acid esters, in particular of pentaerythritol and glycerol, may contain < 60% of the different partial esters resulting from the production.

Saturated aliphatic monocarboxylic acids having 10 to 36 carbon atoms are, for example, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, hydroxystearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid and montanic acid.

Preferred saturated aliphatic monocarboxylic acids having 14 to 22 carbon atoms are, for example, myristic acid, palmitic acid, stearic acid, hydroxystearic acid, arachidic acid and behenic acid.

Saturated aliphatic monocarboxylic acids such as palmitic acid, stearic acid and hydroxystearic acid are particularly preferred.

Saturated aliphatic C₁₀-to C₃₆Carboxylic acids and fatty acid esters are known per se in the literature or can be prepared by methods known in the literature. Examples of pentaerythritol fatty acid esters are those of the above-mentioned particularly preferred monocarboxylic acids.

Esters of pentaerythritol and glycerol with stearic acid and palmitic acid are particularly preferred.

Esters of Guerbet alcohols and glycerol with stearic acid and palmitic acid and optionally hydroxystearic acid are also particularly preferred.

In addition to the inventive UV absorbers and HALS systems, the inventive multilayer products may comprise organic dyes, inorganic colored pigments, fluorescent dyes, further UV absorbers in addition to the UV protective layers (B) and/or (D), IR absorbers and, particularly preferably, optical brighteners.

Layer (a) can be manufactured, for example, by extrusion or by a single-or multi-component injection molding process.

By reacting a compound derived from (a1) with an alkyl chain length (-C) preferably having less than 10 carbon atoms_nH_2n+1Wherein n < 10) alkyl methacrylate, particularly preferably a blend (a) of only n = 1 (methyl methacrylate) of a polyacrylate and a mixture (a2) of biphenyl-substituted triazines of the general formula (I) and phenyl-substituted triazines of the general formula (II) produces the UV protective layers (B) and (D) according to the invention. Compound (a) is then (i) coextruded with polycarbonate in the following manner: allowing a thin UV protective layer of compound (a) to sit with good adhesion on the polycarbonate surface, or (ii) further processing compound (a) into a film, followed by injection molding (hinderspiritzen) or lamination with the polycarbonate back side to form a strongly adherent composite. Coextrusion per se has been described many times in the literature. Here, it is possible to stack thermoplastic melts of different compositions on top of one another by using one or more side extruders and a multi-channel nozzle, or optionally a suitable melt joint upstream of a wide-slit nozzle, and thus to produce multilayer panels or films (for coextrusion see, for example, EP-A0110221, EP-A0110238 and EP-A0716919, for details of the joint and nozzle method see, for example, Johannaber/Ast: "Kunststoff-Maschinenfuhrer", Hanser Verlag, 2000 and Gesellschaft Kunststofftechnik: "Koext Folien Platten: Zukunshifsppektivten, Anforderung, Anladden und Herstellung, Qual ä tshicken", VDI-Verlag, 1990). For back-injection molding of films, see, inter alia, Plastverarbeiter 47 (1996) No. 8-18 ff.

Further, by substituting (b2) a biphenyl group of the formula (I)The mixture of triazine and phenyl-substituted triazine of formula (II) comprises (b1) a mixture containing methyl methacrylate as the main component and possibly further compounds having longer linear or branched alkyl chains (-C)_nH_2n+1Where n > 1), preferably 1. ltoreq. n.ltoreq.10, particularly preferably linear, n = 3 (butyl methacrylate) and one or more solvents, and possibly further lacquer additives, such as fillers, flow assistants, free-radical scavengers, etc. A lacquer formulation (b) containing a UV absorber is then applied to the surface of the polycarbonate shaped part by means of flow coating, dipping, spraying, roller coating or spin coating, followed by physical drying, so that a well-adhering coating is obtained on the PC (see also: Goldschmidt, Streitberger: Lackiertetechnik, BASF Coatings AG, Vincentz Verlag, Hanover, 2002, from page 496).

The UV-stable scratch-resistant layer(s) (C) and (E) of the multilayer product according to the invention are preferably produced by coating the UV-protective layer(s) or uncoated polycarbonate with a scratch-resistant or abrasion-resistant coating system. To this end, a scratch-or abrasion-resistant lacquer, for example a formulation of a polysiloxane lacquer (sol-gel lacquer) or a mixed lacquer, is applied to the UV protective layer(s) or the surface of the uncoated polycarbonate by flow coating, dipping, spray coating, roll coating or spin coating and then cured to form a well-adhering PC/UV protective layer/scratch-resistant layer composite or, in the case of the structures (E) - (a) - (B) - (C), a well-adhering scratch-resistant layer/PC composite.

Within the scope of the present invention, a sol-gel paint is a paint produced by a sol-gel process. The sol-gel process is a process for the synthesis of non-metallic inorganic or hybrid polymeric materials from colloidal dispersions, so-called sols.

For example, such sol-gel coating solutions can be prepared by reacting colloidal silica with organoalkoxysilanes and/OR alkoxysilanes OR compounds of the general formula RSi (OR')₃and/OR an organoalkoxysilane of the formula Si (OR')₄By hydrolysis of an aqueous dispersion of a mixture of alkoxysilanes of the formula RSi (OR')₃(ii) aOne or more) organoalkoxysilanes in which R represents a monovalent C₁-to C₆Alkyl residues or fully or partially fluorinated C₁-C₆-alkyl, vinyl or allyl units, aryl residues or C₁-C₆-alkoxy groups. R is particularly preferably C₁-to C₄-alkyl, methyl, ethyl, n-propyl, isopropyl, tert-butyl, sec-butyl or n-butyl, vinyl, allyl, phenyl or substituted phenyl units. -OR' is independently from each other selected from C₁-to C₆-alkoxy, hydroxy, formyl units and acetyl units. Sol-gel polysiloxane paints sometimes fall within the definition of mixed paints.

Colloidal silica is available, for example, AS Levasil 200A (HC Starck), Nalco 1034A (Nalco Chemical Co), Ludox AS-40, or Ludox LS (GRACE Davison). The following compounds may be mentioned as examples of organoalkoxysilanes: 3,3, 3-trifluoropropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, methyltriacetoxysilane, ethyltriethoxysilane, phenyltrialkoxysilanes (e.g., phenyltriethoxysilane and phenyltrimethoxysilane), and mixtures thereof. The following compounds may be mentioned as examples of alkoxysilanes: tetramethoxysilane and tetraethoxysilane and mixtures thereof.

For example, organic and/or inorganic acids or bases can be used as catalysts.

In one embodiment, The colloidal Silica particles can also be formed in situ by precondensation starting from alkoxysilanes (see "The Chemistry of Silica", Ralph K.Iller, John Wiley & Sons, (1979), p. 312-.

The hydrolysis of the sol-gel solution is stopped or significantly slowed by the addition of a solvent, preferably an alcoholic solvent, such as isopropanol, n-butanol, isobutanol or mixtures thereof. One or more UV absorbers, which have optionally been pre-dissolved in a solvent, are then added to the sol-gel coating solution, followed by an aging step of several hours or days/weeks. Further additives and/or stabilizers may be added, such as flow aids, surface additives, thickeners, pigments, dyes, curing catalysts, IR absorbers and/or adhesion promoters. Hexamethyl-disilazane or similar compounds which may lead to a reduced tendency of the coating to crack may also be used (see also WO 2008/109072 a).

Within the scope of the invention, the hybrid paints are based on the use of hybrid polymers as binders. Hybrid polymers (hybrid: latin-dual source) are polymeric materials in which the building blocks of different material classes are combined at the molecular level. Due to their structure, hybrid polymers can exhibit an entirely novel combination of properties. Unlike composites (well-defined phase boundaries, weak interactions between phases) and nanocomposites (using nanoscale fillers), the structural units of hybrid polymers are connected to each other at the molecular level. This is achieved by chemical methods such as sol-gel methods, which can form organic networks. By using organic reactive precursors, such as organically modified metal alkoxides, organic oligomer/polymer structures can additionally be fabricated. Acrylate paints containing surface-modified nanoparticles that form an organic/inorganic network after curing are also defined as hybrid paints. There are mixed lacquers that are thermally curable and UV-curable.

Thermally, UV-stable sol-gel paints are available, for example, under the product names AS4000 and AS4700 from Momentive Performance Materials. At a layer thickness of from 1 to 20 μm, preferably from 2 to 15 μm, particularly preferably from 4 to 12 μm, the sol-gel polysiloxane lacquer has a degree of matting of from 0.2 to 4, preferably from 0.2 to 2, particularly preferably 0.3. ltoreq. matting (sol-gel layer). ltoreq.1.5.

Possible heat-curable hybrid lacquers are commercially available from Momentive Performance Materials under the name PHC587B or PHC587C or are described in EP-A0570165. The layer thickness should be from 1 to 20 μm, preferably from 3 to 15 μm, particularly preferably from 6 to 8 μm.

UV-curable hybrid lacquers are, for example, UV-curable acrylate lacquers or UV-curable anhydrous hydrolysable silane systems, as described in WO 2008/071363A or DE-A2804283. A commercially available system is UVHC3000 (Momentive Performance Materials). The layer thickness should be from 1 to 25 μm, preferably from 4 to 20 μm, particularly preferably from 8 to 12 μm. The scratch-resistant layer based on the hybrid lacquer should have a gloss reduction at 340 nm of 0.1 to 3, preferably 0.2 to 2.5, particularly preferably 0.3. ltoreq. gloss reduction (hybrid layer). ltoreq.2.

As UV absorbers, use may be made of commercially available moderately polar, mostly hydroxyl-containing UV absorbers and/or inorganic UV absorbers, for example titanium dioxide, zinc oxide or cerium dioxide (EP-A0931820). UV absorbers based on resorcinol and modified by alkoxy-silyl (alkyl) groups of such paint systems have been disclosed in U.S. Pat. No. 5,391,795 and U.S. Pat. No. 5,679,820.

Other typical classes of UV absorbers that may be used in the scratch resistant layer are compounds of the 2-hydroxy-benzophenone class, compounds of the 2- (2-hydroxyphenyl) benzotriazole class, compounds of the 2- (2-hydroxyphenyl) -1,3, 5-triazine class, compounds of the 2-cyanoacrylate class and compounds of the oxalic anilide class. Optionally, modification with groups that lead to an increase in solubility, such as alkoxysilylalkyl groups, is advantageous. The maximum concentration of the UV absorber is determined by its solubility. The minimum concentration results from the desired degree of extinction of the scratch resistant layer, which should be at least 0.2 to 2.5, particularly preferably 0.3. ltoreq. extinction (scratch resistant layer). ltoreq.2. UV absorber contents of 0.5 to 20% by weight, based on the solids content of the scratch-resistant lacquer, are typical.

The scratch resistant layer is applied by methods known in the art, such as a drying hood drying (bake-on-bake), wet hood wetting (wet-on-wet) method, or as specified by the manufacturer.

The multilayer product is preferably selected from the group consisting of sheets, films and three-dimensional shaped bodies.

The invention also provides the use of the multilayer product, in particular for shaped bodies for outdoor applications, such as window panes, which have long-lasting high requirements with regard to visual impression. The fields of application also lie in the field of one-component and two-component injection-molded parts, for example for headlight covers, architectural and automotive glazings.

The invention is further illustrated by, but not limited to, the following examples. The examples of the invention are given only to illustrate preferred embodiments of the invention.

Examples

Examples 1-10

A) Comprises UV Of absorbents PMMA Preparation of the lacquer solution

7.2 g of Elvacite 2021 (Lucite International, UK) were dissolved in 36.4 g each of diacetone alcohol and methoxypropanol. 0.4 g of BYK 300 (BYK Additives and Instruments, Germany), 0.14 g of Tinuvin 144 (Ciba, Switzerland) and a total of 0.7 g of UV absorber (see examples 1 to 10 for details; the absorbers mentioned here are commercially available from Ciba, Switzerland) (corresponding to 10% by weight, based on the solids content of the lacquer) are then added. The lacquer was stirred until the components had completely dissolved and filtered through a pressure filter (Drucknutsche) (2-4 μm cellulose filter).

B) UV Protective layer (B) Application of

On a klickner ferromagnetic FM160, Makrolon with dimensions of 10 × 15 × 0.32 cm was produced with a 45-shot injection apparatus at a material temperature of 300 ℃, a mold temperature of 90 ℃, an injection rate of about 30 mm/sec and a cycle time of about 50 s^®2808 (examples 1 to 5, Bayer Materialscience AG; medium viscosity bisphenol A polycarbonate, MVR 10g/10min, according to ISO1133, no UV stabilization at 300 ℃ and 1.2 kg) or Makrolon^®Optical quality Polycarbonate (PC) sheets of type AL2647 (examples 6-10, Bayer MaterialScience AG; medium viscosity bisphenol A polycarbonate with UV stabilizers and mould release agents; MFR 13g/10min, according to ISO1133, 300 ℃ and 1.2 kg). These injection-molded PC boards were annealed at 120 ℃ for one hour using a hot melt adhesiveCleaning with propanol and drying. The panels were then coated with PMMA lacquer solutions according to the following examples 1 to 10, each containing a UV absorber (dip angle approximately 25 to 45%, temperature of the UV protection solution 23 ℃, room temperature 23 ℃, relative atmospheric humidity 22%), dried for 10 minutes at room temperature and the coating was baked for 30 minutes at 120 ℃.

Examples 1 ： ( Comparison of )

Only 0.7 g of Tinuvin 479 (UV absorber of formula (I); CAS number 204848-45-3) was used as UV absorber in the UV protective layer. In Makrolon^®2808.

Examples 2 ： ( Comparison of )

0.56 g of Tinuvin 479 and 0.14 g of Tinuvin 405 (CAS number 137658-79-8; 2- [ 2-hydroxy-4- [3- (2-ethylhexyl-1-oxy) -2-hydroxypropoxy group)]Phenyl radical]-4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine) is used as UV absorber. In Makrolon^®2808.

Examples 3 ： ( Comparison of )

0.42 g of Tinuvin 479 and 0.28 g of Tinuvin 405 were used as UV absorbers. In Makrolon^®2808.

Examples 4 ： ( Comparison of )

0.42 g of Tinuvin479 and 0.28 g of Tinuvin 1577 (UV absorber of the general formula (II); CAS number 147315-50-2; 2- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) -5- (hexyloxy) -phenol) were used as UV absorbers. In Makrolon^®2808.

Examples 5 ： ( The invention )

0.56 g of Tinuvin 479 and 0.14 g of Tinuvin 1577 were used as UV absorbers. In Makrolon^®2808.

Examples 6 ： ( Comparison of )

Only 0.7 g of Tinuvin 479 was used as UV absorber. In Makrolon^®Coating was performed on AL 2647.

Examples 7 ： ( Comparison of )

0.56 g of Tinuvin 479 and 0.14 g of Tinuvin 405 were used as UV absorbers. In Makrolon^®Coating was performed on AL 2647.

Examples 8 ： ( Comparison of )

0.42 g of Tinuvin 479 and 0.28 g of Tinuvin 405 were used as UV absorbers. In Makrolon^®Coating was performed on AL 2647.

Examples 9 ： ( Comparison of )

0.42 g of Tinuvin 479 and 0.28 g of Tinuvin 1577 were used as UV absorbers. In Makrolon^®Coating was performed on AL 2647.

Examples 10 ： ( The invention )

0.56 g of Tinuvin 479 and 0.14 g of Tinuvin 1577 were used as UV absorbers. In Makrolon^®Coating was performed on AL 2647.

C) Scratch resistant layer (C) Application of

The coated side of the panels coated with the UV protective layer was flow coated with a commercially available UV absorber-containing sol-gel paint (AS4700, Momentive Performance Materials) (dip angle about 25-45%, scratch resistant solution temperature 23 ℃, room temperature 23 ℃, relative atmospheric humidity 22%). After air-drying at room temperature for 30 minutes, the panels were cured for one hour at 100 ℃.

D) And (3) testing:

the thickness of the clear coat was determined by Eta SD 30 from Eta Optik GmbH.

The following adhesion tests were performed:

a.) tearing the tape (using 3M Scotch 610-1PK tape) with and without cross-hatching (similar to ISO 2409 or ASTM D3359);

b.) tearing the tape after 4 hours of storage in boiling water;

c.) tearing the tape after 10 days storage in warm water at about 65 ℃ (similar to ISO 2812-2 and ASTM 870-02), all passed, i.e. the coating was hardly torn (grade 0, according to ISO 2409, or 5B, according to ASTM D3359).

In an Atlas Ci 5000 weatherometer, 0.75W/m at 340 nm²Radiation intensity/nm and 102: drying/rain cycle of 18 minutes, measurement of Makrolon manufactured^®2808 plus UV absorber decomposition (UVAD) of each UV absorber or mixtures thereof in the UV protection of the scratch resistant lacquer. The blackboard temperature was 70 ℃, the sample chamber temperature was 55 ℃, and the atmospheric humidity was 40%.

In an Atlas Ci 5000 weatherometer, 0.75W/m at 340 nm is used²Radiation intensity/nm and 102: examples 6-10 were also weathered with a drying/rain cycle of 18 minutes. The blackboard temperature was 70 ℃, the sample chamber temperature was 55 ℃, and the atmospheric humidity was 40%. UVAD is not possible due to UV protection in polycarbonate.

The yellowness index is calculated as follows. The wavelength-dependent yellowing of the materials was first determined by means of the spectral sensitivity method (Interpretation of the spectral sensitivity and of the action spectra of polymers, P.Trubiroha, Tagungsband der XXII. Donaul ä delgespr ä che, 17.8.2001, Berlin, p.4-1). The spectral distribution of the solar UV light after the UV protection layer was then calculated. The yellowing after weathering can be calculated from the two data sets in a known manner by convolution and integration over time (see also: A. Geburtig, V. Wachtendorf, Tagungsband 34. Jahrestgung der Gesellschaft fur Ulmwater, Ulmween fur afterfansen, 2.3.2005, Pfiniztal, page 159 in this connection).

Haze was determined according to ASTM D1003 using Haze Gard Plus from Byk-Gardner.

As a result:

table 1: examples 1 to 5

Examples	Total layer thickness [ mu m]	Initial haze [% ]]	Initial extinction at 340 nm	Haze after 3000 h wind erosion [% ]]	YI after 3000 h wind erosion	UVAD [MJ-1] 340 nm
							1	11.0	0.17	3.05	2.4	4.46	0.013
2	10.6	0.34	2.85	2.1	4.51	0.016
							3	10.0	0.19	2.45	1.6	4.74	0.017
4	10.0	3.51	*	*	*	*
							5	9.9	0.19	2.75	1.4	4.40	0.010

Table 2: examples 6 to 10

Examples	Total layer thickness [ mu m]	Initial haze [% ]]	Haze after 3000 h wind erosion [% ]]	YI after 3000 h wind erosion
					6	10.4	0.32	0.9	1.71
7	10.6	0.23	0.95	1.61
					8	10.3	0.13	0.8	1.70
9	10.0	5.13	*	*
					10	10.0	0.21	0.7	1.61

No assay was performed because of the high initial haze caused by incompletely dissolved UV absorbers.

The results show that for non-UV stabilized polycarbonate (examples 1 to 5), example 5 of the present invention shows the lowest haze and the lowest yellowing after 3000 hours of weathering. Furthermore, the UV absorber combination of example 5 experienced minimal decomposition, i.e. extinction at 340 nm only decreased UVAD = 0.01, per megajoule radiation dose. In addition, for UV-stable polycarbonates (examples 6 to 10), the structures according to the invention (example 10) result in a minimum haze after 3000 hours of weathering. However, wind damage was not as pronounced as in examples 1 to 5 because of the additional UV protection in the polycarbonate, but a similar trend was still seen in the examples.

It has also been shown that too high a concentration of Tinuvin 1577 as in examples 4 and 9 cannot be used, since the solubility of such UV absorbers in the UV protective layer is significantly limited.

Claims (13)

1. A multilayer product comprising at least one first layer (A), a second layer (B) and a third layer (C), wherein the first layer (A) comprises polycarbonate and the second layer (B) is a UV protective layer for polyalkyl (meth) acrylates and comprises a combination of UV stabilizers of the formulae (I) and (II),

(I)，

wherein X represents OR¹；OCH₂CH₂OR¹；OCH₂CH(OH)CH₂OR¹Or OCH (R)²)COOR³Wherein R is¹In each case representing a branched or unbranched C₁-C₁₃Alkyl radical, C₂-C₂₀-alkenyl, C₆-C₁₂Aryl or CO-C₁-C₁₈-an alkyl group; r²Represents H or C, branched or unbranched₁-C₈-an alkyl group; and R³Is represented by C₁-C₁₂-an alkyl group; c₂-C₁₂-alkenyl or C₅-C₆-a cycloalkyl group,

(II)，

wherein T is¹Is represented by C₁-C₁₈-alkyl or C₄-C₁₈Alkyl interrupted by COO or OCO or O, or interrupted by O and substituted by OH,

and the third layer (C) is a UV-protected scratch-resistant paint.

2. A multi-layer product according to claim 1, characterized in that layer (B) comprises up to 5% by weight, based on layer (B), of a stabilizer of formula (IIIa),

(IIIa)，

wherein Y represents H, R¹OR OR¹And R¹C in each case branched or unbranched₁-C₁₃Alkyl radical, C₂-C₂₀-alkenyl, C₆-C₁₂-aryl or-CO-C₁-C₁₈-alkyl, R²Is H or branched or unbranched C₁-C₈-alkyl, and R³Is C₁-C₁₂-an alkyl group; c₂-C₁₂-alkenyl or C₅-C₆-a cycloalkyl group, and

R⁴byZ-R⁵-Z-R⁶Is composed of (a) wherein

ZIs a divalent functional group, and is a divalent functional group,R⁵is a divalent organic residue, R⁶Is H or C₁-C₂₀-an alkyl group.

3. The multilayer product according to claim 2, wherein the stabilizer of formula (IIIa) is a compound of the formula

(IIIb)，

(IIIc), or

(IIId)，

Wherein

ZIs a divalent functional group, andR⁵is a divalent organic residue, R⁶Is H or C₁-C₂₀-an alkyl group.

4. A multilayer product according to any one of claims 1 to 3, characterized in that the UV absorbers of the formulae (I) and (II) are present in a molar ratio of 9.9: 0.1 to 6.1: 3.9 UV absorbers of the formula (I): the ratio of UV absorbers of formula (II) is used in layer (B).

5. The multilayer product according to any one of claims 1 to 4, further comprising one or more further layers selected from the group consisting of

a. The other UV protective layers (D), preferably likewise made of polyalkylmethacrylate and each comprising at least one UV stabilizer,

b. other scratch resistant layers (E).

6. Multilayer product according to any one of claims 1 to 4, characterized in that it has a sequence of (C) - (B) - (A), (C) - (B) - (A) - (D) - (E) or (C) - (B) - (A) - (E).

7. Multilayer product according to any one of claims 1 to 5, characterized in that it comprises further functional layers (F).

8. A multilayer product according to any one of claims 1 to 7, wherein layer (B) is a cured lacquer formulation having a layer thickness of from 1 to 100 μm, the total proportion of UV absorbers of the formulae (I) and (II) in layer B being from 0.5 to 20% by weight, based on the solids content of the lacquer formulation (B).

9. The multilayer product according to any of claims 1 to 7, wherein layer (B) is a coextruded layer having a layer thickness of from 1 to 500 μm, the total proportion of UV absorbers of the formulae (I) and (II) in layer B being from 0.05 to 20% by weight, based on the total weight of layer (B).

10. The multilayer product according to claim 1, wherein layer (B) is a film having a layer thickness of from 2 μm to 2 mm and the total proportion of UV absorbers of the formulae (I) and (II) in layer (B) is from 0.01 to 20% by weight, based on the total weight of layer (B).

11. Multilayer product according to any one of claims 1 to 10, characterized in that layer (C) and optionally (E) are UV absorber-containing lacquer layers based on sol-gel silicone lacquers, heat-curable hybrid lacquers and/or UV-curable hybrid lacquers.

12. A multilayer product according to any of claims 1 to 11, wherein layer (a) is manufactured by extrusion or mono-or multicomponent injection moulding.

13. Use of a multilayer product according to any of claims 1 to 12 for outdoor applications with long-lasting high requirements with regard to visual impression, in particular for window panes for automobiles and buildings.