DE102009003221A1 - Barrier film, useful e.g. in packaging industry and for organic light-emitting diodes, comprises a weather-resistant carrier layer, a lacquer layer and a barrier layer, where the lacquer layer improves adhesion of the carrier layer - 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 of the carrier layer and thus improving the barrier properties against water vapor and oxygen. An independent claim is also included for producing the barrier film, comprising: (i) equipping a transparent, weather-resistant poly(methyl methacryate) plastic film with a lacquer layer, which improves the adhesion to SiO x, and the lacquer layer is applied by roll coating; (ii) equipping the produced film with an inorganic barrier by physical vacuum evaporation; or (iii) evaporating the physically vacuum evaporated silicon monoxide in the step (ii) by an electron beam; or (iv) thermally evaporating the physically vacuum evaporated silicon monoxide in the step (ii); and (iv) applying an organic lacquer layer (4) on the barrier layer of the produced film.

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 application is the formation of thin surface layers from Z. B. 0.05 to 0.5 mm thickness on stiff, dimensionally stable Basic bodies, such as sheets, cardboard, chipboard, plastic sheets and the same. Stand for the preparation of such coatings different procedures available. So can the slide extruded into a molding compound, smoothed and applied to the substrate be laminated on. By the technique of extrusion coating For example, an extruded strand may be applied to the surface of the substrate and 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, is necessary.

How out K. Noller, 19th European PVSEC, Proceedings, 2004, p. 2156-2159 As is known, permeation processes in organic materials take place in a diffusion-controlled manner, whereas in inorganic layers they are influenced by the imperfections in the inorganic layer. Therefore, 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. In order to achieve a partial discharge voltage of 1000 V, laminates are also produced from several film layers.

How out Amberg-Schwab et al., Journal of Sol-Gel Sciene and Technology 1/2 (1998), p. 141-146 As is known, the imperfections which always occur in inorganic oxide layers can be closed by organic-inorganic sol-gel hybrid systems. Thus, they improve the barrier effect when applied to the inorganic SiOx layer, since they seal the imperfections. This effect is especially strong on polypropylene. The disadvantage of these sol-gel systems, however, is the limited weathering resistance and the long curing process by hydrolysis.

In the patent DE 10260067 A1 Applicant describes deformable scratch-resistant coatings. These have the advantage that they not only for solid moldings, but also for flexible, such. As films can be used. Furthermore, they are UV-stable and dirt-repellent. However, they do not adhere to inorganic layers, such as. For example, silica or alumina layers.

task

Of the Invention is based on the object, a barrier film available which is weather-stable and highly transparent (> 90% in the wavelength range> 380 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 coated with an inorganic oxide layer that improves the barrier function, although this is not possible according to the state of the 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. Fourth, the imperfections of the inorganic Oxide layer sealed with a quick and easy method become.

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. These Carrier layer is treated with a varnish, which is the adhesion an inorganic oxide layer on PMMA improved. The carrier layer also has a sufficient layer thickness to the Partial discharge voltage of 1000 V to ensure. The defects the inorganic layer are sealed with an organic lacquer, which surprisingly improves the barrier. The paint has also surprisingly a good adhesion to the inorganic SiOx layer, although the paint itself only organic components having.

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 barrier film according to the invention has an inorganic layer that is resistant to mechanical influences is protected.
• • The imperfections of the inorganic layer in the invention Foil are lockable by a simple method, which improved the barrier.

The carrier layer

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

The support layer has a thickness of 20 .mu.m to 500 .mu.m, preferably the thickness is 50 .mu.m to 400 .mu.m and most preferably 200 .mu.m to 300 .mu.m. The backing layer contains a UV absorber such as Tinuvin ^® 234, Tinuvin ® 360, Chimasorb ^® 119 or Irganox ^® 1076. The concentration of the UV absorber is from 0 to 20%, preferably 0 to 5%, most preferably 0 to 2% , The carrier layer is further treated with a lacquer which improves the adhesion of the inorganic oxide layer to PMMA. For example, Dynasylan MEMO can be used as the lacquer. The layer thickness of the lacquer is 0 to 50 μm, preferably 0 to 30 μm, very particularly preferably 0 to 10 μm. 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 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 1000V. These are, depending on the thickness, for example PMMA from 250 microns.

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 . 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.

The organic paint

The organic paint is applied to the barrier layer and seals off the imperfections that are present in the barrier layer. It also serves as protection of the inorganic oxide layer from mechanical influences. The organic lacquer has a layer thickness of 0.1 to 50 .mu.m, preferably 1 to 20 .mu.m, more preferably 2-5 microns. The varnish 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. For example, hexanediol dimethacrylate. 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 0.1 wt .-% - 10 wt .-%, preferably 0.5 wt .-% - 5 wt .-%, more preferably 1 wt .-% - 3% initiator, z. B. Irgacure ^® 184 or Irgacure ^® 651. The paint may contain as regulator also 0 wt .-% - 10% sulfur compounds. A variant is to replace part of the main component by 1 wt .-% - 30 wt .-% prepolymer. A prepolymer is understood as meaning a monomer-polymer mixture which results from the fact that the monomer only partially polymerizes (see, for example, US Pat DE 10349544 A1 .)

application

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

embodiment

Carrier layer - lacquer - barrier layer - organic lacquer

A transparent and weather-resistant carrier layer ( 1 ) (preferably PMMA or impact-modified PMMA) is coated with a varnish ( 2 ) coated. An inorganic 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. The barrier layer ( 3 ) is coated with an organic varnish which, surprisingly, further increases the barrier.

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 )
• 3. Application of the organic varnish ( 4 ) on the barrier layer ( 3 ) by means of 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 ,

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).

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).

example 1

• Backing layer: PMMA, film thickness 50 .mu.m, contains 1% of UV absorber Tinuvin ^® 234th
• Paint: 80% hydroxyethyl methacrylate + 20% Dynasylan ^® MEMO, film thickness: 5 microns.
• Barrier layer: SiO _{1.5 applied} by electron beam vacuum evaporation, layer thickness: 40 nm.
• organic paint: 62% Laromer UA 9048 V, 31% hexanediol diacrylate, 2% hydroxyethyl methacrylate, 3% Irgacure 184, 2% butyl acrylate, 1% methacryloxypropyltrimethoxysilane

Example 2

• Carrier layer: impact-resistant PMMA, layer thickness: 250 μm, contains 2% UV absorber Cesa Light ^® GXUVA006.
• Paint: 80% hexanediol diacrylate + 20% Dynasylan ^® MEMO, film thickness: 5 microns. Barrier layer: Al ₂ O ₃ , layer thickness 40 nm, applied by means of magnetron sputtering.
• organic lacquer: 70% hexanediol diacrylate, 17% pentaerythritol tetraacrylate, 5% methyl methacrylate, 2% Irgacure 184, 2% hydroxyethyl methacrylate, 2% methacryloxypropyltrimethoxysilane

Example 3

• Backing layer: coextrudate of PMMA and impact-modified PMMA, layer thickness 150 microns, containing 1.5% of UV absorber Tinuvin ^® 360th
• Lacquer: Nanoresign ^® , layer thickness 3 μm.
• Barrier layer: SiO _1.7 , layer thickness 80 nm, applied by means of magnetron sputtering.
• organic paint: 62% Laromer UA 9048 V, 31% hexanediol diacrylate, 2% hydroxyethyl methacrylate, 3% Irgacure 651, 2% methacryloxypropyltrimethoxysilane

Example 4

• Carrier layer impact-resistant PMMA, layer thickness 150 μm, contains 1.5% UV absorber Tinuvin ^® 360 and 1% Aerosil ^® as additional barrier.
• Lacquer: 80% hexanediol diacrylate + 20% Dynasylan MEMO, coating thickness: 5 μm.
• Barrier layer: SiO _1.7 , layer thickness 60 nm, applied by electron beam vacuum evaporation.
• organic paint: 62% Laromer UA 9048 V, 31% hexanediol diacrylate, 2% hydroxyethyl methacrylate, 3% Irgacure 651, 2% butyl acrylate

Example 5.

• Carrier layer coextrudate of PMMA and impact-modified PMMA, layer thickness 150 microns, containing 1.5% of UV absorber Irganox ^® 1076th
• Paint: 80% hydroxyethyl methacrylate + 20% Dynasylan ^® MEMO, film thickness: 5 microns.
• Barrier layer: Al ₂ O ₃ , layer thickness 20 nm, applied by electron beam vacuum evaporation.
• organic paint: 46% Laromer UA 9048 V, 44% hexanediol diacrylate, 5% hydroxyethyl methacrylate, 3% Irgacure 184, 2% methacryloxypropyltrimethoxysilane

1

backing

2

paint

3

barrier layer

4

organic 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 10025357 A [0005]
• - JP 07074378 A [0005]
• - EP 1018166 B1 [0005, 0005, 0025]
• WO 94/29106 [0006]
• - DE 10260067 A1 [0009]
• - DE 10349544 A1 [0019]

Cited non-patent literature

• K. Noller, 19th European PVSEC, Proceedings, 2004, p. 2156-2159 [0005]
• U. Moosheimer, Galvanotechnik 90 No. 9, 1999, p. 2526-2531 [0007]
• Amberg-Schwab et al., Journal of Sol-Gel Sciene and Technology 1/2 (1998), p. 141-146 [0008]
• ASTM F-1249 [0022]
• - ISO 15105-2 [0023]
• - DIN 53380 T3 [0023]
• - DIN 61730-1 [0024]
• - IEC 60664-1 [0024]

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 they have a transparency of more than 80% in the range of more than 300 nm. Barrier film according to claim 1, characterized in that that applied to the barrier layer, an organic lacquer layer is that improves the barrier function. Barrier film according to claim 1, characterized in that in that the organic lacquer layer consists of a lacquer formulation of the following Composition is formed: a) 1% by weight - 80% by weight mono- or polyfunctional acrylates or methacrylates b) 1 Wt .-% - 50 wt .-% of a prepolymer c) 0 wt .-% - 48 wt .-% of a Siloxangruppen containing acrylate or methacrylate d) 1 wt .-% - 10 wt .-% at least an initiator e) 0.1 wt .-% - 10 wt .-% at least a regulator e) 0.5 wt .-% - 40% of conventional additives Process for the preparation of the barrier film, characterized marked that a) a transparent, weatherproof PMMA plastic film is equipped with a paint coating, the the adhesion to SiOx improved and the lacquer layer by means of rolling Coating is applied. b) in in accordance with claim 7 a) produced Film by means of physical vacuum evaporation with an inorganic Barrier is equipped, or c) at the in 7 b) mentioned physical vacuum evaporation SiO is vaporized by electron beam, or d) in the physical vacuum evaporation mentioned in 7 b) SiO is thermally evaporated, and e) on the barrier layer the film produced in claim 7 a) an organic lacquer layer is applied, which consists of the paint formulation mentioned in claim 6 is formed. 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.