DE102009000449A1 - Barrier film, useful e.g. in packaging industry, display technology and for organic light emitting diodes, comprises weather-resistant carrier layer, lacquer layer and barrier layer, where the lacquer layer improves adhesion on the carrier - Google Patents

Abstract

Barrier film comprises a weather-resistant carrier layer (1), a lacquer layer (2) and a barrier layer (3), where the lacquer layer improves adhesion on the carrier and barrier effect against water vapor and oxygen. An independent claim is included for a preparation of the barrier film, comprising providing a transparent, weather proof plastic poly(methyl methacrylate) with lacquer coating, which improves the adhesion of silicon oxide (SiO x, where x is not defined) and applying the coating by roll coating, (b) providing the obtained film with an inorganic barrier by physical vacuum evaporation, (c) evaporating the silicone monoxide (SiO) during the physical vacuum evaporation, by electron beam, and (d) thermal evaporation of the silicon monoxide during the physical vacuum evaporation.

Description

Field of the invention

The The invention relates to a barrier film made of plastics that is weather-resistant and is transparent and has a high barrier to water vapor and oxygen.

State of the art

Weather-resistant, transparent and impact-resistant films based on polymethacrylate are marketed by the applicant under the name PLEXIGLAS. The 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 under heat and moisture. Furthermore, they avoid the so-called white fracture when impact or bending stress. These films are transparent and remain so even when exposed to heat and moisture, weathering and impact or bending stress.

The Processing of the molding composition to said transparent, impact-resistant Foils are ideally made by extrusion of the melt through a Slot nozzle and smoothing on a roller mill. Such films are characterized by lasting clarity, insensitivity against heat and cold, weather resistance, low yellowing and embrittlement and low whiteness when kinking or folding out and are therefore suitable, for example as a window in tarpaulins, car covers or sails. Such slides have a thickness of less than 1 mm, for example 0.05 to 0.5 mm.

One important scope is the formation of thin Surface layers of z. B. 0.05 to 0.5 mm thickness stiff, dimensionally stable basic bodies, such as sheet metal, Cardboard, chipboard, plastic sheets and the like. For the production of such coatings are different Procedure available. This allows the film to form a molding compound extruded, smoothed and laminated to the substrate become. By the technique of extrusion coating can be an extruded Strand applied to the surface of the substrate and be smoothed by a roller. If as a substrate even a thermoplastic material is used, there is the possibility the coextrusion of both masses to form a surface layer from the clear molding compound of the invention.

PMMA films However, they offer only insufficient barrier properties Water vapor and oxygen, but for medical applications, Applications in the packaging industry, but especially in electrical Applications that are used outdoors, necessary is.

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 AlO _x ) is used in the vacuum coating process (chemical, JP-A-10025357 . JP-A-07074378 ; thermal or electron beam evaporation, sputtering, EP 1 018 166 B1 ) applied. In EP 1018166 B1 It is shown that the ratio of silicon to oxygen of the SiOx layer can influence the UV absorption of the SiOx 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, such as in WO 94/29106 is described. The problem with laminates is that the individual layers separate from one another when exposed to high levels of heat and moisture. Halogenated films are problematic for environmental reasons. Therefore, direct coating of PMMA with an inorganic oxide layer would solve this problem.

How out U. Moosheimer, Galvanotechnik 90 No. 9, 1999, p. 2526-2531 As is known, 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 partial discharge voltage depends on the film material and on the layer thickness. To a part To reach discharge voltage of 1000 V, laminates are also made of several film layers.

task

Of the Invention is based on the object, a barrier film available which is weather-stable and highly transparent (> 80% in the wavelength range> 300 nm), with high Barrier properties to water vapor and oxygen be guaranteed. PMMA fulfills the property the weathering stability, the inorganic oxide layer fulfills the properties of the barrier. The present The invention firstly has the task PMMA as a carrier layer to coat with an inorganic oxide layer that has the barrier function improved, although not possible in the prior art is. Second, the function of protection against UV radiation should not more of the inorganic oxide layer are taken over, so These are optimized exclusively according to optical criteria but from the PMMA layer. Third, already With this combination of materials, a partial discharge voltage of greater 1000 V can be achieved, and not only by the lamination two or more films, as in the prior art. Thereby the step of lamination is saved.

solution

Solved The task is accomplished by a barrier film that is a transparent Backing layer (preferably polymethyl methacrylate (PMMA), impact-resistant PMMA), which is weather-resistant. Of Furthermore, the carrier layer contains a UV absorber. This carrier layer is treated with a varnish, which improves the adhesion of an inorganic oxide layer to PMMA. The carrier layer also has a sufficient layer thickness, to ensure the partial discharge voltage of 1000V.

Advantages of the invention:

• • The invention Barrier film is weather-resistant without additional weather protection.
• 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 (<0.1 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 carrier layer

When Carrier layer are films of preferably polymethylmethacrylate (PMMA) or impact-resistant PMMA (sz-PMMA) used.

The Carrier layer has a thickness of 20 microns to 500 microns on, preferably, the thickness is 50 microns to 400 microns and most preferably at 200 microns to 300 microns. According to the invention, sunscreen agents of Carrier layer can be added. Under sunscreen should UV absorbers, UV stabilizers and radical scavengers be understood.

optional contained UV protectants are z. B. derivatives of benzophenone, its substituents such as hydroxyl and / or alkoxy 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 used as UV protection additive very suitable, 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-chlorobenzotriazole, 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)] counting.

Next The benzotriazoles can also be a UV absorber of the class of 2- (2'-hydroxyphenyl) -1,3,5-triazines, such as phenol, 2- (4,6-diphenyl-1,2,5-triazin-2-xy) -5- (hexyloxy), be used.

UV protectants which can also be used are 2-cyano-3,3-diphenylacrylic acid ethyl ester, 2-etho xy-2'-ethyl-oxalic bisanilide, 2-ethoxy-5-t-butyl-2'-ethyl-oxalic acid bisanilide and substituted phenyl benzoate.

The Light stabilizers or UV protectants can be used as low molecular weight Compounds, as indicated above, in the to be stabilized Polymethacrylatmassen be included. But it can also UV-absorbing groups in the matrix polymer molecules covalently after copolymerization with polymerizable UV absorption compounds, such as As acrylic, methacrylic or allyl derivatives of benzophenone or Benzotriazole derivatives, be bound.

Of the Proportion of UV protectants, which also mixtures chemically different UV protectant is usually 0.01 to 10 wt .-%, especially 0.01 to 5 wt .-%, in particular 0.02 to 2 wt .-% based on the (meth) acrylate copolymer.

Examples of radical scavengers / UV stabilizers are sterically hindered amines, which are known by the name HALS (Hindered Amine Light Stabilizer). They can be used for the inhibition of aging in paints and plastics, especially in polyolefin plastics ( Kunststoffe, 74 (1984) 10, pp. 620-623 ; Paint + lacquer, 96 vintage, 9/1990, pp. 689-693 ). The stabilizing effect of the HALS compounds is due to the tetramethylpiperidine group contained therein. This class of compounds may be both unsubstituted on the piperidine nitrogen and substituted with alkyl or acyl groups. 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

Applied are the radical scavenger / UV stabilizers in the inventive Polymer blends in amounts of 0.01 to 15 wt .-%, especially in Amounts of 0.02 to 10 wt .-%, in particular in amounts of 0.02 to 5 wt .-% based on the (meth) acrylate copolymer.

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, preferred 350 to 2000 nm, more preferably 380 to 800 nm.

The carrier layer also has a sufficient layer thickness to ensure the partial discharge voltage of 1000 V. These are, depending on the thickness, for example PMMA from 250 microns. Partial discharge voltage is understood to be the voltage at which an electrical discharge takes place, which partially bridges the insulation (see DIN EN 60664-1 ).

The paint layer

The carrier layer is further treated with a lacquer which improves the adhesion of the inorganic oxide layer to PMMA. The varnish contains 1-80% by weight of polyfunctional methacrylates or acrylates or mixtures thereof as main component. Preference is given to polyfunctional acrylates, for. For example, hexanediol dimethacrylate, pentaerythritol tetraacrylate or polyurethane acrylates. To increase flexibility, it is possible to add monofunctional acrylates or methacrylates, for example hydroxyethyl methacrylate or lauryl methacrylate. Furthermore, the varnish may contain a component which improves the adhesion to SiOx, for example methacryloxypropyltrimethoxysilane. The paint contains 0.01-10 wt .-%, preferably 0.5-5 wt .-%, particularly preferably 1-3% initiator, z. B. Irgacure ^® 184 or Irgacure ^® 651. The lacquer can contain as regulators also 0-10% sulfur compounds. The paint may also contain 0-10% further additives, such as flow and wetting aids, for. Byk UV 3510, TEGO Glide 440 or TEGO RAD 2200. Furthermore, the paint can also 0-10% UV absorber, such as Tinuvin ^® 234, Tinuvin ^® 360, Chimasorb ^® 119 or Irganox ^® 1076 included. A variant is to replace a part of the main component by 1-30 wt .-% prepolymer. The layer thickness of the lacquer is 0.001 to 50 μm, preferably 0.1 to 30 μm, very particularly preferably 1 to 10 μm. The lacquer layer is prepared by conventional methods, such as Roller application method (for example, roll coating or kiss coating), applied. This lacquer layer not only improves the adhesion between the inorganic oxide layer and the carrier foil ( 1 ), but surprisingly also improves the barrier effect to water vapor and oxygen.

The barrier layer

The barrier layer is applied to the carrier layer and preferably consists of inorganic oxides, for example SiO _x or AlO _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 5-300 nm, preferably 10-100 nm, particularly preferably 20-80 nm.

As AlO _x layers are preferably layers with the ratio of aluminum and oxygen of 2: 3 use. The layer thickness is 5-300 nm, preferably 10-100 nm, particularly preferably 20-80 nm.

The Inorganic oxides can be obtained by physical vacuum deposition (Electron beam or thermal process), magnetron sputtering or Chemsicher vacuum deposition can be applied. A flame, Plasma or corona pretreatment is also possible.

Application:

These Barrier film can be used in the packaging industry, display technology, of organic photovoltaics, in thin-film photovoltaics, in crystalline silicon modules as well as for organic LEDs be used.

embodiments

1. carrier layer paint barrier layer

A transparent and weather-resistant carrier layer ( 1 ) (preferably PMMA or impact-modified PMMA) is coated with a varnish ( 2 ) coated. An anoganic barrier layer ( 3 ) (preferably SiO _x or AlO _x ) applied. The carrier layer ( 1 ) is characterized by the fact that it contains a UV absorber and that it is coated with a varnish, which surprisingly not only improves the adhesion, but also the barrier effect against water vapor and oxygen.

Process:

• 1. application of the paint ( 2 ) on the carrier layer ( 1 ) by means of roll coating
• 2. Vacuum coating (PVD, CVD) of the paint ( 2 )

2. As 1., but with additional barrier in the carrier layer

As Embodiment 1, but in the carrier layer ( 1 ) an additional barrier ( 4 ), which increases the barrier effect by water vapor adsorption (eg ethylvinyl alcohol or inorganic nanoparticles).

Process:

• 1. introduction of the barrier-forming filler, for. B. Nanoparticles in the carrier layer ( 1 ), z. B. by Extrusion.

Otherwise as in embodiment 1.

3. Same as 1. but with additional paint on the barrier layer

As 1., however, the barrier layer is additionally coated with a varnish ( 5 ) (eg sol-gel varnish, Dynasylan MEMO) to improve the barrier.

processes: As in embodiment 1, but in addition Applying the paint to the barrier layer, z. B. by roll coating.

Measurement of the barrier of the invention foil

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

The measurement of the oxygen permeability occurs after ISO 15105-2 ( DIN 53380 T3 ) at 23 ° C / 50% rel. Humidity.

The measurement of the partial discharge voltage occurs after DIN 61730-1 and IEC 60664-1 or DIN EN 60664-1 ,

Examples

Comparative Example:

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

• 1. Trägerschicht: PMMA, Schichtdicke 50 μm, enthält 1% UV-Absorber Tinuvin^® 234. Lack: 26% Hydroxyethylmethacrylat + 52% Polyurethanacrylat Laromer^® UA 9048 + 20% Dynasylan^® MEMO + 1% Irgacure^® 184 + 1% Irgacure^® 907, Schichtdicke: 5 μm. Barriereschicht: SiO_1,5 mittels Elektronenstrahl-Vakuumverdampfung aufgebracht, Schichtdicke: 40 nm.
• 2. Trägerschicht: schlagzähes PMMA, Schichtdicke: 250 μm, enthält 2% UV-Absorber Cesa Light^® GXUVA006. Lack: 80% Hexandioldiacrylat + 18% Dynasylan^® MEMO + 2% Irgacure^®184, Schichtdicke: 5 μm. Barriereschicht: Al₂O₃, Schichtdicke 40 nm, mittels Magnetron-Sputtern aufgebracht.
• 3. Trägerschicht: Coextrudat aus PMMA und schlagzähem PMMA, Schichtdicke 150 μm, enthält 1,5% UV-Absorber Tinuvin^® 360. Lack: Nanoresign^®, Schichtdicke 3 μm. Barriereschicht: SiO_1,7, Schichtdicke 80 nm, mittels Magnetron-Sputtern aufgebracht.
• 4. Trägerschicht schlagzähes PMMA, Schichtdicke 150 μm, enthält 1,5% UV-Absorber Tinuvin^® 360 und 1% Aerosil^® als zusätzliche Barriere. Lack: 78% Hexandioldiacrylat + 20% Dynasylan MEMO, 2% Irgacure^®651, Schichtdicke: 5 μm. Barriereschicht: SiO_1,7, Schichtdicke 60 nm, mittels Elektronenstrahl-Vakuumverdampfung aufgebracht.
• 5. Trägerschicht Coextrudat aus PMMA und schlagzähem PMMA, Schichtdicke 150 μm, enthält 1,5% UV-Absorber Irganox^® 1076. Lack: 26% Hydroxyethylmethacrylat + 52% Polyurethanacrylat Laromer^® UA 9048 + 20% Dynasylan^® MEMO + 1% Irgacure^® 184 + 1% Irgacure^® 907, Schichtdicke: 5 μm. Barriereschicht: Al₂O₃, Schichtdicke 20 nm, mittels Elektronenstrahl-Vakuumverdampfung aufgebracht. zusätzlicher Lack: Dynasylan^® MEMO

A film according to the invention with a 50 μm layer thickness of the carrier layer has a barrier between 0.01 and 0.1 g / (m ² d) (see Example 1).

• 1. Backing layer: PMMA, film thickness 50 microns, 1% UV absorber Tinuvin ^® contains 234. paint: 26% hydroxyethyl methacrylate + 52% polyurethane acrylate Laromer ^® UA 9048 + 20% Dynasylan ^® MEMO + 1% Irgacure ^® 184 + 1% Irgacure ^® 907, layer thickness: 5 μm. Barrier layer: SiO _{1.5 applied} by electron beam vacuum evaporation, layer thickness: 40 nm.
• 2. Support layer: high-impact PMMA, film thickness: 250 microns, contains 2% UV Absorber Light ^® Cesa GXUVA006. Paint: 80% hexane diol diacrylate 18% Dynasylan ^® MEMO + 2% Irgacure ^® 184, thickness: 5 microns. Barrier layer: Al ₂ O ₃ , layer thickness 40 nm, applied by means of magnetron sputtering.
• 3. Backing layer: coextrudate of PMMA and impact-modified PMMA, layer thickness 150 microns, 1.5% UV absorber Tinuvin ^® 360. varnish contains: Nanoresign ^® layer thickness of 3 microns. Barrier layer: SiO _1.7 , layer thickness 80 nm, applied by means of magnetron sputtering.
• 4. Base layer impact-resistant PMMA, layer thickness 150 μm, contains 1.5% UV absorber Tinuvin ^® 360 and 1% Aerosil ^® as additional barrier. Paint: 78% hexane diol diacrylate 20% + Dynasylan MEMO, 2% of Irgacure ^® 651, thickness: 5 microns. Barrier layer: SiO _1.7 , layer thickness 60 nm, applied by electron beam vacuum evaporation.
• 5. carrier layer coextrudate of PMMA and impact-modified PMMA, layer thickness 150 microns, containing 1.5% of UV absorber Irganox ^® 1076. paint: 26% hydroxyethyl methacrylate + 52% polyurethane acrylate Laromer ^® UA 9048 + 20% Dynasylan ^® MEMO + 1% Irgacure ^® 184 + 1% Irgacure ^® 907, layer thickness: 5 μm. Barrier layer: Al ₂ O ₃ , layer thickness 20 nm, applied by electron beam vacuum evaporation. additional paint: Dynasylan ^® MEMO

1

backing

2

paint

3

barrier layer

4

additional barrier

5

additional paint

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 3842796 A1 [0002]
• - JP 10025357A [0006]
• - JP 07074378 A [0006]
• - EP 1018166 B1 [0006, 0006, 0036]
• WO 94/29106 [0007]

Cited non-patent literature

• U. Moosheimer, Galvanotechnik 90 No. 9, 1999, p. 2526-2531 [0008]
• - Kunststoffe, 74 (1984) 10, pp. 620 to 623 [0018]
• - Paint + lacquer, 96 vintage, 9/1990, pp. 689 to 693 [0018]
• - DIN EN 60664-1 [0023]
• ASTM F-1249 [0033]
• - ISO 15105-2 [0034]
• - DIN 53380 T3 [0034]
• - DIN 61730-1 [0035]
• - IEC 60664-1 [0035]
• - DIN EN 60664-1 [0035]

Claims (9)

Barrier film, consisting of a weather-resistant Carrier layer, a lacquer layer and a barrier layer, wherein the lacquer layer the adhesion to the carrier layer and thus the barrier effect against water vapor and Oxygen improves. Barrier film according to claim 1, characterized in that that it is halogen-free. Barrier film according to claim 1, characterized in that that it has a partial discharge voltage of at least 1000V. Barrier film according to claim 1, characterized in that that it has a transparency of more than 80% in the range> 300 nm. Barrier film according to claim 1, characterized in that that the carrier layer additionally with a barrier function Is provided. Barrier film according to claim 1, characterized in that that they have an additional paint on the barrier layer contains, which improves the barrier function. Process for the preparation of the barrier film, characterized marked that a) a transparent, weatherproof PMMA plastic film is equipped with a lacquer coating that the Adhesion to SiOx improved and the paint layer by roll coating is applied, b) produced in according to claim 7a) Film by means of physical vacuum evaporation with an inorganic Barrier is equipped, c) at the physical mentioned in 7b) Vacuum evaporation SiO is evaporated by electron beam, or d) in the physical vacuum evaporation SiO mentioned in 7b) is evaporated. Use of barrier films according to claim 1 in the packaging industry, the display technology and for organic LEDs. Use of barrier films according to claim 1 in the organic photovoltaic, in the thin-film photovoltaic and in crystalline silicon modules.