EP2432638A1

EP2432638A1 - Transparent, weather-resistant barrier foil, production thereof by means of lamination, extrusion lamination or extrusion coating

Info

Publication number: EP2432638A1
Application number: EP10716337A
Authority: EP
Inventors: Claudius Neumann; Florian Schwager; Ghirmay Seyoum; Ekkehard Beer
Original assignee: Evonik Roehm GmbH
Current assignee: Evonik Roehm GmbH
Priority date: 2009-05-19
Filing date: 2010-04-28
Publication date: 2012-03-28
Also published as: BRPI1013032A2; CN102414023A; JP2012527361A; KR20120014161A; SG174882A1; WO2010133427A1; DE102009003225A1; TN2011000462A1; IL215070A0; AU2010251358A1; CA2762599A1; US20120021236A1; MA33483B1; TW201119853A; MX2011012180A

Abstract

The invention relates to a barrier foil, wherein a barrier composite (5) consisting of two carrier foils (3), each of which contains an inorganic barrier (4) (SiOx or AIOx), is combined by lamination or extrusion coating with a weather-resistant protective layer (1), wherein a bonding agent is used as an adhesive layer (2).

Description

Transparent, weather-resistant barrier film, production by lamination, extrusion lamination or

extrusion coating

Field of the invention

The invention relates to the production of a transparent, weather-resistant barrier film by lamination, extrusion lamination (adhesive, melt or Hotmeltkaschierung) or extrusion coating. For this purpose, a transparent film composite consisting of two outer polyolefin or polyester layers, each of which is coated inorganically and adhesively bonded together with the inorganic layer, is provided with a weather-resistant, transparent film (eg PMMA or PMMA polyolefin coextrudate or PMMA). Polyester coextrudate). The inorganic oxide layer has the property of a high, transparent barrier to water vapor and oxygen, while the PMMA layer brings the weathering stability.

State of the art

Weather-resistant, transparent and impact resistant films polymethacrylate base are sold by the applicant under the name PLEXIGLAS ^®. Patent DE 38 42 796 A1 describes the preparation of a clear, impact-resistant acrylate-based molding composition, films and moldings produced therefrom, and a process for the preparation of the molding composition. These films have the advantage that they do not discolor and / or embrittle under heat and moisture. Furthermore, they avoid the so-called white fracture when impact or bending stress. These slides are transparent and stay that way too Exposure to heat and moisture, weathering, impact or bending stress.

The processing of the molding material to said transparent, impact-resistant films is ideally carried out by extrusion of the melt through a slot die and smoothing on a roll mill. Such films are characterized by long-lasting clarity, insensitivity to heat and cold, weather resistance, low yellowing and embrittlement and low whiteness when kinking or folding and are therefore suitable for example as a window in tarpaulins, car covers or sails. Such films have a thickness of less than 1 mm, for example 0.02 mm to 0.5 mm. An important application is the formation of thin surface layers of z. B. 0.02 mm to 0.5 mm thickness on rigid, dimensionally stable bodies, such as sheets, cardboard, chipboard, plastic plates and the like. Various processes are available for the production of such coatings. Thus, the film can be extruded into a molding compound, smoothed and laminated onto the substrate. The technique of extrusion coating allows an extruded strand to be applied to the surface of the substrate and smoothed by a roller. If a thermoplastic material serves as the substrate itself, there is the possibility of coextrusion of both compositions to form a surface layer of the clear molding composition of the invention.

However, PMMA films offer only insufficient barrier properties to water vapor and oxygen, which is necessary for medical applications, applications in the packaging industry, but especially in electrical applications used outdoors.

To improve the barrier properties, transparent, inorganic layers are applied to polymer films. In particular, silicon oxide and aluminum oxide layers have prevailed. This inorganic oxide layer (SiO _x or AIO _x ) is used in the vacuum deposition method (chemically, JP-A-10025357, JP-A- 07074378; thermal or electron beam evaporation, sputtering, EP 1 018 166 B1, JP 2000-307136 A, WO 2005-029601 A2). EP 1018166 B1 shows that the UV absorption of the SiO x layer can be influenced via the ratio of silicon to oxygen of the SiO x layer. This is important to protect underlying layers from UV radiation. The disadvantage, however, is that as the ratio of silicon to oxygen changes, the barrier property also changes. Thus transparency and barrier can not be varied independently of each other.

The inorganic oxide layer is sometimes applied mainly to polyesters and polyolefins because these materials withstand the temperature stress during the evaporation process. In addition, the inorganic oxide layer adheres well to polyesters and polyolefins, the latter undergoing corona treatment prior to coating. However, since these materials are not weather-stable, they are often laminated with halogenated films, as described, for example, in WO 94/29106. However, halogenated films are problematic for environmental reasons.

As is known from U. Moosheimer, Galvanotechnik 90 No. 9, 1999, p. 2526-2531, the coating of PMMA with an inorganic oxide layer does not improve the barrier to water vapor and oxygen since PMMA is amorphous. However, unlike polyesters and polyolefins, PMMA is weather-stable.

The applicant uses in DE 102009000450.5 paints, which caused a good adhesion between the inorganic layer and the adhesion promoter. As is known to those skilled in the art, adhesion between organic and inorganic layers is more difficult to achieve than between like layers. task

The object of the invention is to provide a barrier film which is stable to weathering and highly transparent (> 80% in the wavelength range> 300 nm), whereby high barrier properties to water vapor and oxygen are ensured. PMMA fulfills the property of weathering stability, the inorganic oxide layer fulfills the properties of the barrier.

First, the present invention has the object to combine PMMA as a carrier layer with inorganic oxide layers.

Secondly, the function of protection against UV radiation should no longer be borne by the inorganic oxide layer, so that it can be optimized only by optical criteria, but by the PMMA layer. Thirdly, a partial discharge voltage of greater than 1,000 V is to be achieved by this combination of materials.

Fourth, the function of the PMMA layer is to protect the underlying polyolefin or polyester layers from weathering.

solution

The task is solved by a barrier film, which is weather-resistant. The properties are achieved by a multilayer film, wherein the individual layers are combined by vacuum deposition, lamination, extrusion lamination (adhesive, melt or Hotmeltkaschierung) or extrusion coating. These conventional methods, such. In SEM Selke, JD Culter, RJ Hernandez, "Plastics Packaging", 2nd Edition, Hanser Publishing, ISBN 1-56990-372-7 at pages 226 and 227.

Since the direct inorganic coating of PMMA according to the prior art is not possible, a polyester or polyolefin film is coated with the inorganic layer. The PMMA layer protects the polyester or polyolefin film from the effects of the weather.

The problem of adhesion between inorganic and organic layers is overcome by bonding two inorganically coated films with the inorganic side inwards, with the organic side of the film facing outwards. This can then be easily connected to other organic polymers.

The adhesion between the inorganic layers can be achieved, for example, with a polyurethane-based adhesive optimized for inorganic layers.

The film composite containing the two inorganic layers can be joined together by means of a hotmelt adhesive with PMMA, sz-PMMA, or a film composite of PMMA or sz-PMMA and polyolefin or polyester by extrusion lamination.

The PMMA layer also contains a UV absorber that protects the polyester or polyolefin film from UV radiation. However, the UV absorber may also be present in the polyolefin or polyester layer. Instead of the PMMA layer, a coextrudate of PMMA and polyolefin can be used, which brings cost advantages, since polyolefins are more favorable than PMMA. Advantages of the invention:

The barrier film according to the invention is weather-stable.

The barrier film according to the invention is halogen-free.

The barrier film according to the invention has a high barrier to water vapor and oxygen (<0.05 g / (m ² d)).

The barrier film according to the invention protects underlying layers from UV radiation, independently of the composition of the SiO _x layer.

The barrier film according to the invention can be produced cost-effectively, since a thin film can be used for the discontinuous process of inorganic vacuum deposition.

The barrier film according to the invention can be produced simply, since only inorganic with inorganic layers and organic with organic layers have to be connected to one another.

The protective layer

As a protective layer, films of preferably polymethylmethacrylate (PMMA) or impact-resistant PMMA (sz-PMMA) are used.

Impact-modified poly (meth) acrylate plastic

The impact-modified poly (meth) acrylate plastic consists of 20 wt .-% to 80 wt .-%, preferably 30 wt .-% to 70 wt .-% of a poly (meth) acrylate matrix and 80 wt .-% bis 20% by weight, preferably 70% by weight to 30% by weight, of elastomer particles having an average particle diameter of 10 nm to 150 nm (measurement by means of the ultracentrifuge method, for example).

Preferably, the elastomer particles distributed in the poly (meth) acrylate matrix have a core with a soft elastomer phase and a hard phase bonded thereto.

The impact-modified poly (meth) acrylate plastic (szPMMA) consists of a proportion of matrix polymer, polymehs from at least 80 wt .-% units of methyl methacrylate and optionally 0 wt .-% to 20 wt .-% units of copolymerizable with methyl methacrylate monomers and a in The matrix distributed proportion of impact modifiers based on crosslinked poly (meth) acrylates

The matrix polymer consists in particular of 80% by weight to 100% by weight, preferably 90% by weight to 99.5% by weight, of free-radically polymerized methyl methacrylate units and, if appropriate, 0% by weight to 20% by weight .-%, preferably to 0.5 wt .-% - 10 wt .-% of further radically polymehsierbaren comonomers, eg. As C to C ₄ alkyl (meth) acrylates, in particular methyl acrylate, ethyl acrylate or butyl acrylate. Preferably, the average molecular weight M _w (Weight average) of the matrix in the range from 90,000 g / mol to 200,000 g / mol, in particular 100,000 g / mol to 150,000 g / mol (determination of M _w by gel permeation chromatography with reference to polymethyl methacrylate as calibration standard). The molecular weight M _w can be determined, for example, by gel permeation chromatography or by a scattered light method (see, for example, BHF Mark et al., Encyclopedia of Polymer Science and Engineering, 2nd Edition, Vol. 10, pages 1 et seq., J. Wiley, 1989). ,

Preference is given to a copolymer of 90% by weight to 99.5% by weight of methyl methacrylate and 0.5% by weight to 10% by weight of methyl acrylate. The Vicaterweichunqemperaturen VET (ISO 306-B50) may be in the range of at least 90, preferably from 95 to 112 ⁰ C.

The impact modifier

The polymethacrylate matrix contains an impact modifier, which z. B. may be a two- or three-shell constructed impact modifier.

Impact modifiers for polymethacrylate plastics are well known. Production and construction of impact-modified polymethacrylate molding compositions are, for. In EP-A 0 113 924, EP-A 0 522 351, EP-A 0 465 049 and EP-A 0 683 028.

impact modifiers

In the polymethacrylate matrix are 1 wt .-% to 30 wt .-%, preferably 2 wt .-% to 20 wt .-%, particularly preferably 3 wt .-% to 15 wt .-%, in particular 5 wt .-%. % to 12% by weight of an impact modifier which is an elastomeric phase of crosslinked polymer particles. The impact modifier is obtained in a conventional manner by Perlpolymehsation or by emulsion polymerization. In the simplest case, crosslinked particles obtainable by means of bead polymerisation and having an average particle size in the range from 10 nm to 150 nm, preferably 20 nm to 100, in particular 30 nm to 90 nm. These usually consist of at least 40% by weight. %, preferably 50% by weight to 70% by weight of methyl methacrylate, 20% by weight to 40% by weight, preferably 25% by weight to 35% by weight of butyl acrylate and also 0.1% by weight to 2 wt .-%, preferably 0.5 wt .-% to 1 wt .-% of a crosslinking monomer, for. B. a polyfunctional (meth) acrylate such. B. allyl methacrylate and optionally other monomers such. B. 0 wt .-% to 10 wt .-%, preferably 0.5 wt .-% to 5 wt .-% of Ci-C ₄ -alkyl methacrylates, such as ethyl acrylate or butyl methacrylate, preferably methyl acrylate, or other vinylic polymerizable monomers such as z. Styrene.

Preferred impact modifiers are polymer particles which may have a two- or three-layer core-shell structure and are obtained by emulsion polymerization (see, for example, EP-A 0 113 924, EP-A 0 522 351, EP-A 0 465 049 and EP -A 0 683 028). However, for the purposes of the invention, suitable particle sizes of these emulsion polymers must be in the range from 10 nm to 150 nm, preferably from 20 nm to 120 nm, particularly preferably 50 nm to 100 nm.

A three-layer or three-phase structure with a core and two shells can be designed as follows. An innermost (hard) shell may, for. B consists essentially of methyl methacrylate, small proportions of comonomers, such as. For example, ethyl acrylate and a crosslinker, z. As allyl methacrylate, exist. The middle (soft) shell can z. B. from butyl acrylate and optionally styrene, while the outermost (hard) shell substantially corresponds to the matrix polymer, whereby the compatibility and good binding to the matrix is effected. The polybutyl acrylate content of the impact modifier is crucial for the impact strength and is preferably in the range of 20 wt .-% to 40 wt .-%, particularly preferably in the range of 25 wt .-% to 35 wt .-%. Impact-modified polymethacrylate molding compounds

In the extruder, the toughening modifier and matrix polymer can be melt-blended into toughened polymethacrylate molding compositions. The discharged material is usually first cut into granules. This can be further processed by means of extrusion or injection molding into moldings, such as plates or injection-molded parts.

Two-phase impact modifier according to EP 0 528 196 A1

Preferred, in particular for film production, but not limited thereto, is a system known in principle from EP 0 528 196 A1 which is a two-phase, impact-modified polymer of:

a1) 10 wt .-% to 95 wt .-% of a continuous hard phase having a glass transition temperature 7 _mg above 70 ⁰ C, composed of

a11) 80 wt .-% to 100 wt .-% (based on a1) of methyl methacrylate and a12) 0 wt .-% to 20 wt .-% of one or more other ethylenically unsaturated, radically polymerizable monomers, and

a2) 90 wt .-% to 5 wt .-% of an advantageous in the hard phase toughening phase having a glass transition temperature 7 _mg below -10 ⁰ C, composed of

a21) from 50% to 99.5% by weight of a Ci-Cio-alkyl acrylate (based on a2) a22) 0.5 wt .-% to 5 wt .-% of a crosslinking monomer having two or more ethylenically unsaturated , radically polymerizable radicals, and a23) optionally further ethylenically unsaturated, radically polymerizable monomers, wherein at least 15% by weight of the hard phase a1) is covalently linked to the toughening phase a2).

The biphasic impact modifier can be produced by a two-stage emulsion polymerization in water, such as. B. in DE-A 38 42 796 described. In the first stage, the tough phase a2) is produced, which is constructed to at least 50 wt .-%, preferably more than 80 wt .-%, of lower alkyl acrylates, resulting in a glass transition temperature of 7 _mg of this phase of below -10 ⁰ C results. As crosslinking monomers a22) are (meth) acrylic esters of diols, such as ethylene glycol dimethacrylate or 1, 4-butanediol dimethacrylate, aromatic compounds having two vinyl or allyl groups, such as divinylbenzene, or other crosslinkers having two ethylenically unsaturated, radically polymerizable radicals, such , As allyl methacrylate as a graft crosslinker used.

As crosslinkers with three or more unsaturated, radically polymerizable groups, such as allyl groups or (meth) acrylic groups, examples include thallyl cyanurate, trimethylolpropane thacrylate and trimethacrylate and pentaerythritol tetraacrylate and tetramethacrylate mentioned. Further examples are given in US Pat. No. 4,513,118.

The ethylenically unsaturated, free-radically polymerizable monomers mentioned under a23) can be, for example, acrylic or methacrylic acid and their alkyl esters having 1-20 carbon atoms, if not already mentioned, where the alkyl radical can be linear, branched or cyclic. Furthermore, a23) may comprise further free-radically polymerizable aliphatic comonomers which are copolymerizable with the alkyl acrylates a21). However, significant proportions of aromatic comonomers, such as styrene, alpha-methylstyrene or vinyltoluene should be excluded because they lead to undesirable properties of the molding compound A, especially when weathered. In the first stage toughening phase, attention must be paid to the particle size adjustment and nonuniformity. The particle size of the toughening phase depends essentially on the concentration of the emulsifier. Advantageously, the particle size can be controlled by the use of a seed latex. Particles having an average particle size (weight average) below 130 nm, preferably below 70 nm, and having a polydispersity Uso of the particle size below 0.5, (Uso is determined from an integral consideration of the particle size distribution, which is determined by ultracentrifuge. Uso = [(rgo - Ho) / r ₅ o] - 1, where r _w , r ₅₀ , r ₉₀ = mean integral particle radius for which 10,50,90% of the particle radii are below and 90,50,10% of the Particle radii are above this value), preferably below 0.2, are achieved with emulsifier concentrations of 0.15 to 1, 0 wt .-%, based on the water phase. This is especially true for anionic emulsifiers, such as the most preferred alkoxylated and sulfated paraffins. As polymerization initiators z. B. 0.01 to 0.5 wt .-% alkali metal or ammonium peroxodisulfate, based on the water phase used and the polymerization is initiated at temperatures of 20 to 100 ⁰ C. Preference is given to redox systems, for example a combination of 0.01 wt .-% to 0.05 wt .-% of organic hydroperoxide and 0.05 wt .-% to 0.15 wt .-% Nathumhydroxymethylsulfinat, at temperatures of 20 to 80 ⁰ C used.

The hard phase to the tough phase a2) at least 15 wt .-% covalently linked a1) has a glass transition temperature of at least 70 ⁰ C, and can be composed exclusively of methyl methacrylate. Comonomers a12) may contain up to 20% by weight of one or more further ethylenically unsaturated, radically polymerizable monomers in the hard phase, alkyl (meth) acrylates, preferably alkyl acrylates having 1 to 4 carbon atoms, being used in amounts such that the above-mentioned glass transition temperature is not exceeded. The polymerization of the hard phase a1) in a second stage also proceeds in emulsion using the usual auxiliaries, as used, for example, for the polymerization of the tough phase a2).

In a preferred embodiment, the hard phase contains low molecular weight and / or copolymerized UV absorbers in amounts of from 0.1% by weight to 10% by weight, preferably 0.5% by weight to 5% by weight, based on A as a component of the comonomer components a12) in the hard phase. Illustrative of the polymehsierbaren UV absorbers, as described inter alia in US 4,576,870, may be mentioned 2- (2'-hydroxyphenyl) -5-methacrylamidobenzotriazol or 2-hydroxy-4-methacryloxybenzophenone. Low molecular weight UV absorbers may be, for example, derivatives of 2-hydroxybenzophenone or 2-hydroxyphenylbenzotriazole or salicylic acid phenylester. In general, the low molecular weight UV absorbers have a molecular weight of less than 2 × 10 ³ (g / mol). Particularly preferred are UV absorbers with low volatility at the processing temperature and homogeneous miscibility with the hard phase a1) of the polymer A.

Coextrudates of polymethacrylates and polyolefins or polyesters can also be used. Coextrudates of polypropylene and PMMA are preferred. Furthermore, a fluorinated, halogenated layer is possible, such. Example, a coextrudate of PVDF with PMMA or a blend of PVDF and PMMA, although the advantage of halogen freedom would be eliminated. The protective layer has a thickness of 20 microns to 500 microns, preferably, the thickness is 50 microns to 400 microns and most preferably from 200 microns to 300 microns. Light stabilizers

According to the invention, sunscreen agents can be added to the carrier layer. Sunscreens are to be understood as UV absorbers, UV stabilizers and free-radical scavengers.

Optional UV protectants are z. As derivatives of benzophenone, whose substituents such as hydroxyl and / or alkoxy groups are usually in the 2- and / or 4-position. These include 2-hydroxy-4-n-octoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4, 4'-dimethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone. Furthermore, substituted benzotriazoles are very suitable as UV protection additive, for which especially 2- (2-hydroxy-5-methylphenyl) -benzotriazole, 2- [2-hydroxy-3,5-di (alpha, alpha-dimethyl) benzyl) -phenyl] -benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) -benzotriazole, 2- (2-hydroxy-3, 5-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-Hydroxy-3,5-di-t-butylphenyl) -5-chlorobenzthazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) -benzotriazole, 2- (2-hydroxy-5 -t-butylphenyl) -benzotriazole, 2- (2-hydroxy-3-sec-butyl-5-t-butylphenyl) -benzotriazole, and 2- (2-hydroxy-5-t-octylphenyl) -benzotriazole, phenol, 2, 2'-methylenebis [6- (2H-benztriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl)].

In addition to the benzotriazoles, a UV absorber of the class of 2- (2'-hydroxyphenyl) -1, 3,5-thazines, such as, for example, phenol, 2- (4,6-diphenyl-1,2,5-triazine) can also be used. 2-xy) -5- (hexyloxy).

UV protectants which can also be used are 2-cyano-3,3-diphenylacrylic acid ethyl ester, 2-ethoxy-2'-ethyl-oxalic acid bisanilide, 2-ethoxy-5-t-butyl-2'-ethyl-oxalic acid bisanilide and substituted phenyl benzoate. The light stabilizers or UV protectants can be present as low molecular weight compounds, as indicated above, in the polymethacrylate compositions to be stabilized. But it can also UV-absorbing groups in the matrix polymer molecules covalently after Copolymehsation with polymerizable UV absorption compounds, such as. As acrylic, methacrylic or allyl derivatives of benzophenone or Benztriazolderivaten be bound. The proportion of UV protection agents, which may also be mixtures of chemically different UV protection agents, is generally 0.01% by weight to 10% by weight, especially 0.01% by weight to 5% by weight. -%, In particular 0.02 wt .-% to 2 wt .-% based on the (meth) acrylate copolymer.

As an example of radical scavenger / UV stabilizers here are hindered amines, which are known under the name HALS (Hindered Amine Light Stabilizer) are known. They can be used for the inhibition of aging processes in paints and plastics, in particular in polyolefin plastics (Kunststoffe, 74 (1984) 10, pp. 620 to 623; Paint + Varnish, 96 Volume, 9/1990, pp. 689 to 693 ). The stabilizing effect of the HALS compounds is due to the tetramethylpiperidine group contained therein. This class of compounds may be both unsubstituted and substituted with alkyl or acyl groups on the piperidine atom. The sterically hindered amines do not absorb in the UV range. They catch formed radicals, which the UV absorbers can not do. Examples of stabilizing HALS compounds which can also be used as mixtures are:

Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro (4,5) decane-2,5-dione, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, poly (N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-) hydroxy-piperidine-succinic acid ester) or bis (N-methyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate.

Particularly preferred UV-absorbers are, for example, Tinuvin ^® 234, Tinuvin ^® 360, Chimasorb ^® 119 or Irganox ^® 1076th The radical scavengers / UV stabilizers are used in the polymer blends according to the invention in amounts of from 0.01% by weight to 15% by weight, in particular in amounts of from 0.02% by weight to 10% by weight, in particular Amounts of 0.02% by weight to 5% by weight, based on the (meth) acrylate copolymer.

The UV absorber is preferably in the PMMA layer, but it may be included in the polyolefin or polyester layer.

The protective layer also has a sufficient layer thickness to ensure the partial discharge voltage of 1,000V. These are, depending on the thickness, for example PMMA from 250 microns. Partial discharge voltage is understood to mean the voltage at which an electrical discharge takes place, which partially bridges the insulation (see DIN EN 60664-1).

The carrier layer

The carrier layer used are films of preferably polyolefins (PE, PP) or polyesters (PET, PET-G, PEN). Also, films of other polymers can be used (for example, polyamides or polylactic acid). The carrier layer has a thickness of 1 .mu.m to 100 .mu.m, preferably the thickness is 5 .mu.m to 50 .mu.m and most preferably 10 .mu.m to 30 .mu.m.

The carrier layer has a transparency of more than 80%, preferably more than 85%, particularly preferably more than 90% in the wavelength range of> 300 nm, preferably 350 to 2000 nm, particularly preferably 380 to 800 nm.

The barrier layer

The barrier layer is applied to the carrier layer and preferably consists of inorganic oxides, for example SiO _x or AIO _x . However, other inorganic materials (for example SiN, SiN _x O y, ZrO, TiO ₂ , ZnO, Fe _x O y, transparent organometallic compounds) can also be used. For the exact layer structure see exemplary embodiments. As SiO _x layers are preferably layers with the ratio of silicon and oxygen of 1: 1 to 1: 2, more preferably 1: 1, 3 to 1: 1, 7 use. The layer thickness is 5 nm - 300 nm, preferably 10 nm - 100 nm, particularly preferably 20 nm - 80 nm.

For x, in the case of AIOx, a range of 0.5 to 1.5 applies; preferably from 1 to 1.5, and most preferably from 1.2 to 1.5 (where x = 1.5 AI ₂ O ₃ ). The layer thickness is 5 nm - 300 nm, preferably 10 nm - 100 nm, particularly preferably 20 nm - 80 nm.

The inorganic oxides can be obtained by physical vacuum deposition (electron beam or thermal process), magnetron sputtering or chemical safety Vacuum deposition can be applied. This can be reactive (under oxygen supply) or non-reactive. Flame, plasma or corona pretreatment is also possible.

The barrier compound - consisting of 2 inorganic coated carrier layers

The composite of 2 inorganic coated (= provided with barrier layer carrier layers) has the advantage that the two inorganic layers are protected by the two outer support layers. Lamination with the protective film therefore does not damage the barrier layer. Furthermore, the adhesive used to make the composite can be optimized for the inorganic layer. As adhesives, the formulations described in the section "The Adhesive Layer" can be used, preference being given here to a polyurethane-based two-component adhesive.

The adhesive layer

The adhesive layer lies between the protective layer and the barrier layer. It allows the adhesion between the two layers. The adhesive layer has a thickness of 1 μm-100 μm, preferably 2 μm-50 μm, particularly preferably 2 μm-20 μm. The adhesive layer can be formed from a paint formulation which is subsequently cured. This is preferably done by UV radiation, but can also be done thermally. The adhesive layer contains 1% by weight to 80% by weight of polyfunctional methacrylates or acrylates or mixtures thereof as the main component. Preference is given to polyfunctional acrylates, for. B. Hexandioldimethycrylat used. To increase flexibility, monofunctional acrylates or methacrylates can be added, for example Hydroxyethyl methacrylate or lauryl methacrylate. Furthermore, the adhesive layer optionally contains a component which improves the adhesion to SiOx, for example siloxane-containing acrylates or methacrylates, e.g. B. Methacryloxypropylthmethoxysilane. The silane oxide-containing acrylates or methacrylates may be contained in the adhesive layer at 0% by weight to 48% by weight. The adhesive layer contains 0.1 wt .-% - 10 wt .-%, preferably 0.5 wt .-% - 5 wt .-%, particularly preferably 1 wt .-% - 3% initiator, z. B. Irgacure ^® 184 or lrgacure ^® 651. The adhesive layer can be used as a regulator also 0 wt .-% - 10 wt .-%, preferably 0.1 wt .-% - 10 wt .-%, particularly preferably 0.5 wt. -% - contain 5% sulfur compounds. A variant is to replace a part of the main component by 0 wt .-% - 30 wt .-% prepolymer. The adhesive component optionally contains 0 wt .-% - 40 wt .-% of the usual additives for adhesives. The adhesive layer can also be formed from a hot melt adhesive. This may consist of polyamides, polyolefins, thermoplastic elastomers (polyester, polyurethane or copolyamide elastomers) or copolymers. Preferred are ethylene-vinyl acetate copolymers or ethylene-acrylate copolymers or ethylene-methacrylate copolymers. The adhesive layer can be applied by roller coating in the lamination or by means of a die in the extrusion lamination or in the extrusion coating.

A prepolymer is understood as meaning a monomer-polymer mixture which is formed by the monomer only partially polymerizing (see, for example, DE10349544A1).

application

This barrier film can be used in the packaging industry, display technology, organic photovoltaics, thin-film photovoltaics, crystalline silicon modules and organic LEDs. embodiments

Figure 1 shows an embodiment with protective layer - adhesive layer - barrier composite, lamination

A carrier layer (3) (eg PET) is coated with a barrier layer (4) (eg SiO _x ). This is connected to a second SiOx-coated carrier layer by roller application method by means of an adhesive layer (2 '). By lamination, the protective layer (1) (eg PMMA) is applied to this barrier composite. As an adhesive layer (2) for the lamination, for example, an adhesion promoter based on acrylate or methacrylate can be used. This can be applied by roller application method (roll or kiss coating). The protective layer (1) is characterized in that it contains a UV absorber.

Process:

1. Vacuum coating (PVD, CVD) of the carrier layer (4)

2. Production of the barrier composite by bonding two coated carrier layers by means of roller application method, whereby an adhesive layer (2 ') is formed

3. Application of the protective layer (1) to the barrier composite (5) by means of lamination (roller application method) using an adhesion promoter which represents the adhesive layer (2)

4. Curing of the adhesive layer (2) by UV radiation FIG. 2 shows an exemplary embodiment with protective layer-barrier composite, extrusion coating

A carrier layer (3) (eg PET) is coated with a barrier layer (4) (eg SiO _x ). This is connected to a second SiOx-coated carrier layer by roller application method by means of an adhesive layer (2 '). The protective layer (1) in the state of the melt (for example PMMA-PP coextrudate) is applied to this barrier composite by extrusion coating. Optionally, the adhesion of the protective layer on the barrier layer by an adhesive layer (2), z. B. adhesion promoter on acrylate or methacrylate-based, or hot melt adhesive, z. B. on ethylene-acrylate copolymer-based improved.

The protective layer (1) is characterized in that it contains a UV absorber and that it consists of two or three layers (PMMA and PP or PMMA, adhesion promoter or hot melt adhesive and PP).

Process:

1. Vacuum coating (PVD, CVD) of the carrier layer (4)

3. applying the protective layer (1) on the barrier composite (5) by means of multi-layer extrusion coating possibly using a hot melt adhesive, which is the adhesive layer (2) FIG. 3 shows an exemplary embodiment with protective layer-barrier composite-carrier layer, extrusion lamination

A carrier layer (3) (eg PET) is coated with a barrier layer (4) (eg SiO _x ). This is connected to a second SiOx-coated carrier layer by roller application method by means of an adhesive layer (2 '). The protective layer (1) (eg PMMA film or coextrudates of PMMA and polyolefins) is applied to this barrier composite (5) by extrusion lamination. As adhesive layer (2) for the lamination, for example, a hot melt adhesive, for. As ethylene-acrylate copolymer-based, are used. This melt adhesive is extruded by means of a nozzle in the state of the melt between the barrier composite (5) and the protective layer (1). The protective layer (1) is characterized in that it contains a UV absorber.

Process:

1. Vacuum coating (PVD, CVD) of the carrier layer (4)

3. Extrusion lamination of the adhesive layer (2) in the state of the melt between the protective layer (1) and the barrier composite Measurement of the barrier of the film according to the invention

The measurement of the water vapor permeability of the film system is carried out according to ASTM F-1249 at 23 ° C / 85% rel. Humidity.

The partial discharge voltage is measured according to DIN 61730-1 and IEC 60664-1 or DIN EN 60664-1.

Examples

Comparative Example:

A film according to the prior art (EP 1 018 166 B1), z. B. SiOx-coated ETFE with 50 micron layer thickness has a water vapor permeability of 0.7 g / (m ² d).

A film according to the invention with a 50 μm layer thickness of the barrier composite (5) has a water vapor permeation rate between 0.01 and 0.05 g / (m ² d) (see Example 1).

example 1

Protective layer (1): PMMA, film thickness 50 .mu.m, contains 1% of UV absorber Tinuvin ^®

234th

Adhesive layer (2): 62% Laromer UA 9048 V, 31% hexanediol dimethacrylate, 2%

Hydroxyethyl methacrylate, 3% Irgacure 651, 2% 3

Methacryloxypropylthmethoxysilan Barrier compound (5) consisting of:

Carrier layer (3): PET Mitsubishi Hostaphan RN12, layer thickness: 12 μm. Barrier layer (4): SiO 2 _{, 5 applied} by electron beam vacuum evaporation, layer thickness: 40 nm.

Adhesive layer (2 '): Two-component system Liofol LA 2692-21 and hardener UR 7395- 22 from Henkel

Example 2:

Protective layer (1): impact-resistant PMMA, layer thickness: 250 μm, contains 2% UV absorber Cesa Light ^® GXUVA006.

Adhesive layer (2): 62% Laromer UA 9048 V, 31% hexanediol diacrylate, 2% hydroxyethyl methacrylate, 3% Irgacure 184, 2% butyl acrylate

Barrier compound (5) consisting of:

Carrier layer (3): PEN, layer thickness: 20 μm

Barrier layer (4): Al ₂ O ₃ , layer thickness 40 nm, applied by means of magnetron sputtering.

Adhesive layer (2 '): 60% Laromer UA 9048 V, 30% hexanediol diacrylate, 2%

Hydroxyethyl methacrylate, 3% Irgacure 184, 2% butyl acrylate, 4%

Methacryloxypropylthmethoxysilan Example 3

Protective layer (1): Coextrudate of PMMA and impact-resistant PMMA, layer thickness

150 microns, containing 1, 5% UV absorber Tinuvin ^® 360th

Adhesive layer (2): 62% Ebecryl 244, 31% hexanediol diacrylate, 2%

Hydroxyethyl methacrylate, 3% Irgacure 651, 2% Glymo

Barrier compound (5) consisting of:

Carrier layer (3): PET, layer thickness 23 μm.

Barrier layer (4): SiOi _{, 7} , layer thickness 80 nm, applied by means of magnetron sputtering.

Adhesive layer (2 '): 70% hexanediol diacrylate, 17% pentaerythritol tetraacrylate, 5%

Methyl methacrylate, 2% Irgacure 184, 2% hydroxyethyl methacrylate, 2%

Methacryloxypropylthmethoxysilan

Example 4:

Protective layer (1): (. Eg Plex 8943F) coextrudate of impact-resistant PMMA, film thickness 40 microns containing 1, 5% UV absorber, Tinuvin ^® 360 and polyethylene (. Eg Dowlex SC 2108 G), layer thickness 200 microns. Adhesive: Dupont Bynel 22 E 780 (ethylene-acrylate copolymer). Adhesive layer (2): Dupont Bynel 22 E 780 Barrier compound (5) consisting of:

Carrier layer (3): PET Mitsubishi Hostaphan RN75, layer thickness 75 μm Barrier layer (4): SiO 2 _{, 7} , layer thickness 80 nm, applied by electron beam vacuum evaporation.

The% data in the examples always mean wt%. LIST OF REFERENCE NUMBERS

1 protective layer

2 adhesive layer

2 'adhesive layer of the barrier composite (5)

3 carrier layer

4 barrier layer

5 barrier compound

Claims

claims

1. barrier film, consisting of a weather-resistant protective layer and a barrier composite, wherein the protective layer is weather-resistant and the barrier composite contains two inorganic oxide layers, which improve the barrier effect against water vapor and oxygen.

2. barrier film according to claim 1,

characterized in that

it is halogen-free.

3. barrier film according to claim 1, characterized

that

it has a partial discharge voltage of at least 1000V.

4. barrier film according to claim 1,

characterized in that

it has a transparency of more than 80% in the range of more than 300 nm.

5. barrier film according to claim 1,

characterized in that

between the barrier compound and the protective layer is an adhesive layer which is formed from a bonding agent of the following composition: a) 1 wt .-% - 80 wt .-% of mono- or polyfunctional acrylates or methacrylates b) 0 wt .-% - 30 wt % of a prepolymer c) 0% by weight to 48% by weight of a siloxane-containing acrylate or methacrylate d) 0.1% by weight to 10% by weight of at least one initiator e) 0% by weight 10 wt .-% of at least one regulator f) 0 wt .-% - 40 wt .-% of conventional additives

6. barrier film according to claim 1,

characterized in that

between the inorganic barrier layer and the protective layer is an adhesive layer which is formed from a hot melt adhesive.

7. Process for the production of the barrier film,

characterized in that

a) a carrier film (polyolefin, polyester) is coated by means of vacuum evaporation or sputtering inorganic and this film is bonded by means of an adhesive layer with another inorganic coated film and the resulting film composite with a weather-resistant plastic film (PMMA, coextrudate of PMMA and polyolefin) by means of lamination is combined, or

b) a carrier film (polyolefin, polyester) is coated inorganically by means of vacuum evaporation or sputtering and this film is bonded by means of an adhesive layer with another inorganic coated film and the resulting film composite with a weather-resistant plastic film (PMMA, coextrudate of PMMA and polyolefin) by Extrusionslamination is combined, or

c) a support film (polyolefin, polyester) is coated by means of vacuum evaporation or sputtering inorganic and this film is bonded by means of an adhesive layer with another inorganic coated film and the resulting film composite with a weather-resistant plastic film (PMMA, coextrudate of PMMA and polyolefin) by extrusion coating combined, and

d) in the physical vacuum evaporation SiO mentioned in 7 a) to c) is evaporated by means of electron beam, or e) is thermally evaporated in the physical vacuum evaporation SiO mentioned in 7 a) to c).

8. Use of barrier films according to claim 1 in the packaging industry, the display technology and for organic LEDs.

9. Use of barrier films according to claim 1 in organic photovoltaics, in the thin-film photovoltaic and in crystalline silicon modules.