HK1166041A - Transparent, weather-resistant barrier foil, production thereof by means of lamination, extrusion lamination or extrusion coating - Google Patents

Description

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

Technical Field

The invention relates to the production of transparent, weather-resistant barrier films by lamination, extrusion lamination (adhesive lamination, melt lamination or hot melt lamination) or extrusion coating. For this purpose, a transparent film composite consisting of two outer polyolefin or polyester layers, each provided with an inorganic coating and bonded to one another internally with the inorganic layer, is laminated with a weather-resistant transparent film (for example PMMA or PMMA-polyolefin coextrusions or PMMA-polyester coextrusions). The inorganic oxide layer has high transparent barrier properties against water vapor and oxygen, while the PMMA layer is responsible for the weathering stability.

Background

Weather-resistant, transparent and impact-resistant polymethacrylate-based films are known by the applicant under the nameAnd (5) selling. DE 3842796A 1 describes the preparation of transparent impact-resistant acrylate-based molding materials, films and moldings produced therefrom and a process for the preparation of the molding materials. These films have the advantage that they do not discolor and/or become brittle under the action of heat and moisture. In addition, they avoid so-called white cracks under impact or bending stress. These films are transparent and remain so even under the action of heat and moisture, under the action of weather and under impact or bending stresses.

The processing of the moulding compound to give the transparent impact-resistant film is ideally carried out by extruding the melt through a wide slot die and smoothing it on a roll mill. Such films exhibit permanent transparency, insensitivity to heat and cold, weathering resistance, slight yellowing and embrittlement and exhibit slight white cracking on folding or creasing and are therefore suitable as windows in, for example, canvas sheds, car roofs or sailboats. Such films have a thickness of less than 1mm, for example 0.02mm to 0.5 mm. An important field of application is the formation of thin surface layers, for example of thickness from 0.02 to 0.5mm, on rigid, dimensionally stable base bodies, such as metal sheets, cardboard, particle board, plastic sheets and the like. Various methods can be used to prepare such coverings. For example, the film may be extruded to obtain a molding compound, flattened and laminated to a substrate. Using extrusion coating techniques, the extruded strands can be applied to the surface of a substrate and smoothed using a roller. If thermoplastics are used as the substrate itself, there is the possibility of coextrusion of the two materials in the case of a surface layer formed from the transparent molding compound of the invention.

However, PMMA films only provide an insufficient barrier against water vapour and oxygen, which is necessary for applications in medical applications, in the packaging industry, and in particular in electrical applications in outdoor use.

To improve the barrier properties, a transparent inorganic layer is applied to the polymer film. In particular, silicon oxide and aluminum oxide layers have become mature. Such an inorganic oxide layer (SiO)_xOr AlO_x) Is applied by ｃA vacuum coating method (chemically, JP- ｃA-10025357, JP- ｃA-07074378; thermal or electron beam evaporation, sputtering, EP 1018166B 1, JP2000-307136A, WO 2005-029601 a 2). SiO is described in EP 1018166B 1_xThe UV absorption of the layer may be by SiO_xThe silicon to oxygen ratio of the layer. This is important to protect the layers located therebelow from UV radiation. However, a disadvantage is that as the ratio of silicon to oxygen changes, so does the barrier properties. Thus, the transparency and barrier properties may not change independently of each other.

The inorganic oxide layer is sometimes applied mainly to polyesters and polyolefins because these materials withstand the thermal stress during the evaporation process. Furthermore, the inorganic oxide layer adheres well to polyesters and polyolefins, which undergo corona treatment prior to coating. However, because these materials are not stable to weathering, they are often laminated with halogenated films, such as described in WO 94/29106. However, halogenated films are problematic for environmental reasons.

As known from u.mooheimer, Galvanotechnik 90 No.9, 1999, pages 2526-2531, coating PMMA with an inorganic oxide layer does not improve the barrier properties against water vapor and oxygen, since PMMA is amorphous. In contrast to polyesters and polyolefins, however, PMMA is weather-stable.

In DE 102009000450.5, the applicant used a coating which resulted in 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 adhesion between two layers of the same type.

Disclosure of Invention

Disclosure of the invention

The invention is based on the object of providing a weather-resistant and highly transparent (80% in the wavelength range > 300 nm) barrier film, in which high barrier properties against water vapor and oxygen are ensured. PMMA meets the weathering stability performance, while the inorganic oxide layer meets the barrier performance.

The invention has for its first time the object of combining PMMA as support layer with an inorganic oxide layer.

Secondly, the function of protection from UV radiation will no longer be undertaken by the inorganic oxide layer, whereby this can be optimized only according to the optical standard, and not for those of the PMMA layer. Third, partial discharge voltages greater than 1000V will be achieved with this material combination.

Fourth, the PMMA layer has the function of protecting the underlying polyolefin or polyester layer from weathering effects.

Solution scheme

The object of the invention is achieved by a barrier film which is stable to weathering. The properties are achieved by multilayer films in which the individual layers are bonded to one another by vacuum vapor deposition, lamination, extrusion lamination (adhesive lamination, melt lamination or hot melt lamination) or extrusion coating. Conventional methods can be used for this purpose, as described, for example, in S.E.M.Selke, J.D.Culter, R.J.Hernandez, "Plastics Packaging", second edition, Hanser-Verlag, ISBN 1-56990-.

Since direct inorganic coating of PMMA is not possible according to the prior art, polyester or polyolefin films are provided with an inorganic layer by vapor deposition. The PMMA layer protects the polyester or polyolefin film from weathering effects.

The problem of adhesion between inorganic and organic layers is circumvented by adhesively bonding two inorganic-coated films to each other, wherein the films have an inorganic side facing inwards and an organic side facing outwards. This can then be easily joined with other organic polymers.

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

The film composite containing the two inorganic layers may be joined to each other by extrusion lamination using a hot melt adhesive with PMMA, impact PMMA, or a film composite including PMMA or impact PMMA and polyolefin or polyester.

The PMMA layer also contains a UV absorber that protects the polyester or polyolefin film from UV radiation. However, UV absorbers may also be present in the polyolefin or polyester layer. Instead of a PMMA layer, it is also possible to use a co-extrusion of PMMA and polyolefin, which has a cost advantage, since polyolefin is more economical than PMMA.

The invention has the advantages that:

● the barrier film according to the invention is weather resistant.

● the barrier film according to the invention is halogen free.

● the barrier film according to the invention has a high barrier action against water vapour and oxygen (< 0.05 g/(m)²d))。

● Barrier films according to the invention are independent of SiO_xThe composition of the layer protects the underlying layer from UV radiation.

● barrier films according to the invention can be economically produced because thin films can be used in a discontinuous inorganic vacuum vapor deposition process.

● the barrier film according to the invention can be easily produced because it is only necessary that the inorganic layer and the inorganic layer are bonded to each other and that the organic layer and the organic layer are bonded to each other.

Protective layer

Preferably, a film comprising polymethyl methacrylate (PMMA) or impact-resistant PMMA (sz-PMMA) is used as protective layer.

Impact-modified poly (meth) acrylate plastics

Impact-modified poly (meth) acrylate plastics consist of 20% to 80% by weight, preferably 30% to 70% by weight, of a poly (meth) acrylate matrix and 80% to 20% by weight, preferably 70% to 30% by weight, of elastomer particles having an average particle diameter of 10 to 150nm (measured, for example, using the ultracentrifuge method).

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

Impact-modified poly (meth) acrylate plastics (szPMMA) consist of a proportion of a matrix polymer (obtained by polymerization of at least 80% by weight of methyl methacrylate units and optionally of 0% to 20% by weight of units of monomers copolymerizable with methyl methacrylate) and a proportion of impact modifiers distributed in the matrix, the impact modifiers being based on crosslinked poly (meth) acrylates.

The matrix polymer is composed in particular of from 80% to 100% by weight, preferably from 90% to 99.5% by weight, of free-radically polymerized methyl methacrylate units and optionally from 0% to 20% by weight, preferably from 0.5% to 10% by weight, of further comonomers capable of free-radical polymerization, for example C (meth) acrylate₁-C₄Alkyl esters, in particular methyl acrylate, ethyl acrylate or butyl acrylate. Preferably, the average molecular weight M of the matrix_w(weight average) in the range of 90000g/mol to 200000g/mol, in particular 100000g/mol to 150000g/mol (M is determined by means of gel permeation chromatography with reference to polymethyl methacrylate as calibration standard_w). For example, molecular weight M_wCan be determined by gel permeation chromatography or by light scattering methods (see, for example, H.F. Mark et al, Encyclopedia of Polymer science and Engineering, 2 nd edition, volume 10, page 1 and subsequent pages, J.Wiley, 1989).

Copolymers formed from 90% to 99.5% by weight of methyl methacrylate and 0.5% to 10% by weight of methyl acrylate are preferred. The Vicat softening temperature VET (ISO 306-B50) may be in the range of at least 90 ℃, preferably 95-112 ℃.

Impact modifier

The polymethacrylate matrix contains an impact modifier, which may be, for example, an impact modifier consisting of two or three shells.

Impact modifiers for polymethacrylates are well known. The preparation and constitution of impact-modified polymethacrylate moulding compositions is described, for example, in EP-A0113924, EP-A0522351, EP-A0465049 and EP-A0683028.

Impact modifier

The polymethacrylate matrix contains 1% to 30% by weight, preferably 2% to 20% by weight, particularly preferably 3% to 15% by weight, in particular 5% to 12% by weight, of an impact modifier which is an elastomeric phase composed of crosslinked polymer particles. The impact modifiers are obtained in a manner known per se by bead polymerization or by emulsion polymerization.

In the simplest case, the particles are crosslinked particles obtainable by beading polymerization, their average particle size being from 10nm to 150nm, preferably from 20nm to 100nm, in particular from 30nm to 90 nm. They are generally composed of: at least 40% by weight, preferably from 50% by weight to 70% by weight, of methyl methacrylate, from 20% by weight to 40% by weight, preferably from 25% by weight to 35% by weight, of butyl acrylate, and from 0.1% by weight to 2% by weight, preferably from 0.5% by weight to 1% by weight, of a crosslinking monomer, for example a polyfunctional (meth) acrylate, for example allyl methacrylate, and optionally further monomers, for example from 0% by weight to 10% by weight, preferably from 0.5% by weight to 5% by weight, of methacrylic acid C₁-C₄Alkyl esters, such as ethyl acrylate or butyl methacrylate, preferably methyl acrylate or other vinyl-polymerizable monomers, such as styrene.

Preferred impact modifiers are polymer particles which can have a two-or three-layer core-shell structure and are obtained by emulsion polymerization (see, for example, EP-A0113924, EP-A0522351, EP-A0465049 and EP-A0683028). However, for the purposes of the present invention, suitable particle sizes of these emulsion polymers must be in the range from 10nm to 150nm, preferably from 20nm to 120nm, particularly preferably from 50nm to 100 nm.

A three-layer or three-phase structure having one core and two shells can be completed as follows. The innermost (hard) shell may, for example, consist essentially of methyl methacrylate, a small proportion of a comonomer, such as ethyl acrylate, and a proportion of a crosslinker, such as allyl methacrylate. The middle (soft) shell may for example consist of butyl acrylate and optionally styrene, while the outermost (hard) shell largely corresponds to the matrix polymer, resulting in compatibility and good bonding to the matrix. The proportion of polybutylacrylate in the impact modifier is decisive for the impact resistance and is preferably from 20% to 40% by weight, particularly preferably from 25% to 35% by weight.

Impact-modified polymethacrylate moulding materials

Impact modifiers and matrix polymers can be mixed in the melt in an extruder to give impact-modified polymethacrylate molding materials. The discharged material is generally first cut into pellets. This can be further processed into molded articles, such as sheets or injection molded parts, using extrusion or injection molding.

Two-phase impact modifier according to EP 0528196A 1

In particular for the preparation of films, although not restricted thereto, preference is given to using systems known in principle from EP 0528196 a1, which are two-phase impact-modified polymers comprising:

a1) 10-95% by weight cohesive, glass transition temperature T_mgA hard phase greater than 70 ℃, consisting of:

a11) from 80% by weight to 100% by weight, based on a1, of methyl methacrylate, and

a12) from 0% by weight to 20% by weight of one or more other ethylenically unsaturated monomers capable of free-radical polymerization, and

a2) 90-5% by weight of glass transition temperature T distributed in the hard phase_mgA ductile phase below-10 ℃, consisting of:

a21) 50-99.5% by weight of acrylic acid C₁-C₁₀An alkyl ester (based on a2),

a22) from 0.5% to 5% by weight of a crosslinking monomer containing two or more ethylenically unsaturated groups capable of free radical polymerization, and

a23) optionally other ethylenically unsaturated monomers capable of free-radical polymerization,

wherein at least 15% by weight of the hard phase a1) is covalently linked to the tough phase a 2).

The two-phase impact modifiers can be produced by two-stage emulsion polymerization in water, as described, for example, in DE-A3842796. In the first stage, a tough phase a2) is produced, which comprises at least 50% by weight, preferably more than 80% by weight, of lower alkyl acrylates, so that a glass transition temperature T of this phase of less than-10 ℃ is obtained_mg. Crosslinking monomers a22) used are (meth) acrylates of diols, such as ethylene glycol dimethacrylate or 1, 4-butanediol dimethacrylate, aromatics with two vinyl or allyl groups, such as divinylbenzene, or other crosslinking agents with two ethylenically unsaturated, free-radically polymerizable groups, such as allyl methacrylate, as graft crosslinking agents.

Crosslinking agents with three or more unsaturated, free-radically polymerizable groups, such as allyl or (meth) acryloyl groups, which may be mentioned by way of example, are triallyl cyanurate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate, and pentaerythritol tetraacrylate and pentaerythritol tetramethacrylate. Other examples in this respect are given in US 4,513,118.

The ethylenically unsaturated monomers mentioned under a23) which are capable of free-radical polymerization may be, for example, acrylic or methacrylic acid or their alkyl esters having from 1 to 20 carbon atoms, where the alkyl groups may be linear, branched or cyclic, as long as they have not been mentioned. In addition, a23) may comprise further aliphatic comonomers which are capable of free-radical polymerization and are copolymerizable with the alkyl acrylates a 21). However, it is intended to exclude a considerable proportion of aromatic comonomers, such as styrene, α -methylstyrene or vinyltoluene, since these lead (in particular under climatic action) to undesirable properties of the molding compositions A.

When producing the ductile phase in the first stage, care must be taken to adjust the particle size and its polydispersity. The particle size of the tough phase here depends essentially on the concentration of emulsifier. Advantageously, the particle size can be controlled by using a seed latex. Based on the aqueous phase, an average (weight average) particle size of less than 130nm, preferably less than 70nm, and a polydispersity U of the particle size are obtained using an emulsifier concentration of 0.15 to 1.0% by weight₈₀Less than 0.5 (U)₈₀Is determined by taking into account the integral of the particle size distribution determined by ultracentrifugation. The following is applicable: u shape₈₀＝[(r₉₀-r₁₀)/r₅₀]-1, wherein r₁₀、r₅₀、r₉₀For this particle radius, it applies that 10, 50, 90% of the particles have a radius below this value and 90, 50, 10% have a radius above this value), preferably below 0.2. This applies in particular to anionic emulsifiers, such as, for example, the particularly preferred alkoxylated and sulfated alkanes. The polymerization initiators used are, for example, from 0.01% to 0.5% by weight, based on the aqueous phase, of alkali metal peroxodisulfates or ammonium peroxodisulfates and initiate the polymerization at temperatures of from 20 to 100 ℃. Preferably, redox systems are used at temperatures of 20-80 ℃, for example, a combination consisting of 0.01-0.05% by weight of organic hydroperoxide and 0.05-0.15% by weight of sodium hydroxymethylsulfinate.

The hard phase a1), which is covalently linked at least at 15% by weight to the ductile phase a2), has a glass transition temperature of at least 70 ℃ and may consist exclusively of methyl methacrylate. Up to 20% by weight of one or more other ethylenically unsaturated monomers capable of free-radical polymerization may be present in the hard phase as comonomer a12), where the alkyl (meth) acrylates, preferably those having from 1 to 4 carbon atoms, are used in amounts such that the above-mentioned glass transition temperatures are not undershot.

The polymerization of the hard phase a1) is carried out in the second stage, likewise in emulsion, with the use of customary auxiliaries, for example those which are also used for the polymerization of the tough phase a 2).

In a preferred embodiment, the hard phase contains low molecular weight and/or polymerized UV absorbers in an amount of from 0.1% by weight to 10% by weight, preferably from 0.5% by weight to 5% by weight, based on a as constituent of the comonomer component a12) in the hard phase. As polymerizable UV absorbers, mention may be made, in particular, as described in U.S. Pat. No. 4, 4576870, of 2- (2' -hydroxyphenyl) -5-methacrylaminobenzotriazole or 2-hydroxy-4-methacryloyloxybenzophenone. The low molecular weight UV absorber may be, for example, a derivative of 2-hydroxybenzophenone or 2-hydroxyphenylbenzotriazole or phenyl salicylate. In general, low molecular weight UV absorbers have a molecular weight of less than 2X 10³(g/mol) molecular weight. UV absorbers which have a low volatility at the processing temperature and are homogeneously miscible with the hard phase a1) of the polymer A are particularly preferred.

It is also possible to use coextrudates of polymethacrylates and polyolefins or polyesters. A coextrusion of polypropylene and PMMA is preferred. In addition, fluorinated halogenated layers are also possible, for example, a coextrusion of PVDF with PMMA or a blend of PVDF and PMMA, but here the advantage of being halogen-free would not be present.

The protective layer has a thickness of 20 μm to 500 μm, preferably 50 μm to 400 μm, very particularly preferably 200 μm to 300 μm.

Light stabilizers

According to the invention, light stabilizers can be added to the carrier layer. Light stabilizers are understood to mean UV absorbers, UV stabilizers and radical scavengers.

The UV stabilizers which are optionally present are, for example, derivatives of benzophenone, the substituents, such as hydroxyl and/or alkoxy, being present in the 2-and/or 4-position in a majority. They 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 additional UV stabilizers, which include in particular 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- [ 2-hydroxy-3, 5-bis (. alpha.,. alpha. -dimethylbenzyl) phenyl ] benzotriazole, 2- (2-hydroxy-3, 5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3-5-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3, 5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3, 5-di-tert-amylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2-hydroxy, 2- (2-hydroxy-3-sec-butyl-5-tert-butylphenyl) benzotriazole and 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, phenol, 2' -methylenebis [6- (2H-benzotriazol-2-yl) -4- (1, 1, 3, 3-tetramethylbutyl) ].

In addition to benzotriazole, it is also possible to use 2- (2' -hydroxyphenyl) -1, 3, 5-triazines, for example UV absorbers of the phenol, 2- (4, 6-diphenyl-1, 2, 5-triazin-2-yl (xy)) -5- (hexyloxy) class.

Further UV stabilizers which may be used are ethyl 2-cyano-3, 3-diphenylacrylate, 2-ethoxy-2 '-ethyl-oxalanilide, 2-ethoxy-5-tert-butyl-2' -ethyl-oxalanilide and substituted phenyl benzoates.

Light stabilizers or UV stabilizers may be present as low molecular weight compounds, such as those given above, in the polymethacrylate material to be stabilized. However, the UV-absorbing group may also be covalently bonded within the matrix polymer molecule after copolymerization with a polymerizable UV-absorbing compound, such as an acryloyl derivative, a methacryloyl derivative, or an allyl derivative of a benzophenone derivative or a benzotriazole derivative. The proportion of UV stabilizers, which may also be a mixture of chemically different UV stabilizers, is generally from 0.01 to 10% by weight, in particular from 0.01 to 5% by weight, and in particular from 0.02 to 2% by weight, based on the (meth) acrylate copolymer.

As examples of free-radical scavengers/UV stabilizers, mention may be made here of sterically Hindered amines, which are known as HALS (Hindered Amine Light Stabilizer). They can be used for inhibiting the ageing process in coatings and plastics, in particular in polyolefin plastics (Kunststoffe, 74(1984)10, pp. 620-623; Farbe + Lock, 96 years 9/1990, pp. 689-693). The tetramethylpiperidine group present in the HALS compound is responsible for the stabilization of said compound. Such compounds may be unsubstituted at the piperidine nitrogen or substituted thereon by an alkyl or acyl group. The sterically hindered amines do not absorb in the UV range. They trap the free radicals formed, which the UV absorbers are not able to exert. Examples of HALS compounds which are stabilizing and which can also be used in 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-. beta. -hydroxyethyl-2, 2, 6, 6-tetramethyl-4-hydroxypiperidine succinate) or bis- (N-methyl-2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate.

Particularly preferred UV absorbers are, for example,234、360、119 or1076。

The amount of radical scavengers/UV stabilizers used in the polymer mixtures according to the invention is from 0.01 to 15% by weight, in particular from 0.02 to 10% by weight, especially from 0.02 to 5% by weight, based on the (meth) acrylate copolymer.

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

The protective layer also has a sufficient layer thickness to ensure a partial discharge voltage of 1000V. For example, in the case of PMMA, this is from 250 μm, depending on the thickness. Partial discharge voltage is understood to mean the voltage at which the discharge takes place, which partially bridges the insulating part (see DIN EN 60664-1).

Support layer

Films made of polyolefins (PE, PP) or polyesters (PET, PET-G, PEN) are preferably used as carrier layers. Films composed of other polymers, such as polyamide or polylactic acid, may also be used. The support layer has a thickness of 1 μm to 100 μm; the thickness is preferably from 5 μm to 50 μm, very particularly preferably from 10 μm to 30 μm.

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

Barrier layer

The barrier layer is applied to the support layer and is preferably made of an inorganic oxide, for example SiO_xOr AlO_xAnd (4) forming. However, other inorganic materials (e.g., SiN) may also be used_xO_y、ZrO、TiO₂、ZnO、Fe_xO_yTransparent organometallic compounds). For the precise layer structure, see the examples. SiO used_xThe layer is preferablyLayers having a silicon to oxygen ratio of from 1: 1 to 1: 2, particularly preferably from 1: 1.3 to 1: 1.7. The layer thickness is from 5nm to 300nm, preferably from 10nm to 100nm, particularly preferably from 20nm to 80 nm.

In AlO_xWhere applicable, 0.5 to 1.5 for x; preferably 1 to 1.5, very particularly preferably 1.2 to 1.5 (where x is 1.5 Al)₂O₃). The layer thickness is from 5nm to 300nm, preferably from 10nm to 100nm, particularly preferably from 20nm to 80 nm.

The inorganic oxide may be applied using physical vacuum deposition (electron beam or thermal processes), magnetron sputtering or chemical vacuum deposition. This can be done either reactively (supplying oxygen) or non-reactively. Flame pretreatment, plasma pretreatment or corona pretreatment are also possible.

Barrier composite Material-consisting of 2 support layers with inorganic coating

A composite material comprising 2 carrier layers with inorganic coatings (i.e. carrier layers provided with barrier layers) has the advantage that the two inorganic layers are protected by two outer carrier layers. Therefore, the barrier layer is not damaged when laminated with the protective film. In addition, the binder used to prepare the composite material may be optimized for the inorganic layer. The formulations described in the section "adhesive layer" may be used as adhesives. Polyurethane-based two-component adhesives are preferred here.

Adhesive layer

An adhesive layer is present between the protective layer and the barrier layer. It allows adhesion between the two layers. The adhesive layer has a thickness of 1 μm to 100 μm, preferably 2 μm to 50 μm, particularly preferably 2 μm to 20 μm. The adhesive layer may be formed from a coating formulation that is subsequently cured. This is preferably done by UV radiation, but can also be done thermally. The adhesive layer contains 1 wt% to 80 wt% of a multifunctional methacrylate or acrylate or a mixture thereof as a main component. Preferably, multifunctional acrylates are used, such as hexanediol dimethacrylate. To increase flexibility, monofunctional acrylates or methacrylates, for example hydroxyethyl methacrylate or methacrylic acid, may be addedAnd (4) lauryl ester. In addition, the adhesive layer optionally contains modified SiO_xAdhesive components, for example acrylates or methacrylates containing siloxane groups, for example methacryloxypropyltrimethoxysilane. The siloxane group-containing acrylate or methacrylate may be present in the adhesive layer in an amount of 0 wt% to 48 wt%. The adhesive layer contains from 0.1% to 10% by weight, preferably from 0.5% to 5% by weight, particularly preferably from 1% to 3% by weight, of an initiator, for example184 or651. The adhesive layer may also contain from 0% to 10% by weight, preferably from 0.1% to 10% by weight, particularly preferably from 0.5% to 5% by weight, of sulfur compounds as regulators. In one variant, a portion of the main component is replaced by from 0% to 30% by weight of the prepolymer. The adhesive component optionally contains from 0% to 40% by weight of additives customary for adhesives. However, the adhesive layer may also be formed of a hot melt adhesive. This may consist of polyamides, polyolefins, thermoplastic elastomers (polyester, polyurethane or copolyamide elastomers) or copolymers. Ethylene-vinyl acetate copolymers or ethylene-acrylate copolymers or ethylene-methacrylate copolymers are preferred. The adhesive layer may be coated in a lamination using a roll coating method or in an extrusion lamination using a nozzle or in an extrusion coating.

Prepolymers are understood to mean monomer-polymer mixtures which are formed by only partial polymerization of monomers (see, for example, DE10349544A 1).

Applications of

Such barrier films can be used in the packaging industry, display technology, organic photovoltaic technology, thin film photovoltaic technology, crystalline silicon modules and in organic LEDs.

Detailed Description

Examples

Figure 1 shows an embodiment with a protective layer-adhesive layer-barrier composite (lamination)

With barrier layer 4 (e.g. SiO)_x) A carrier layer 3 (for example PET) is applied. It is mixed with a second SiO_xThe coated carrier layers are joined by means of an adhesive layer 2' by means of a roll coating method. A protective layer 1 (for example PMMA) is applied on this barrier composite by lamination. For example, acrylate or methacrylate based adhesion promoters may be used as the adhesive layer 2 for such lamination. This can be applied by a roll coating method (roll coating or kiss coating). The protective layer 1 is characterized in that it contains a UV absorber.

The method comprises the following steps:

1. vacuum-coated (PVD, CVD) carrier layer 4

2. The barrier composite was prepared by bonding two coated carrier layers using a roll coating process, thereby producing adhesive layer 2'

3. The protective layer 1 is applied to the barrier composite 5 by lamination (roll coating method) with the aid of an adhesion promoter as the adhesive layer 2

4. Curing of the adhesive layer 2 by UV radiation

Figure 2 shows an embodiment with a protective layer-barrier composite (extrusion coating)

With barrier layer 4 (e.g. SiO)_x) A carrier layer 3 (for example PET) is applied. It is mixed with a second SiO_xThe coated carrier layers are joined by means of an adhesive layer 2' by means of a roll coating method. A protective layer 1 (for example a PMMA-PP co-extrudate) in the melt state is applied on this barrier composite by extrusion coating. Optionally, the adhesion of the protective layer on the barrier layer can be improved by an adhesive layer 2, for example an acrylate or methacrylate based adhesion promoter, or a hot melt adhesive (for example based on ethylene-acrylate copolymers).

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).

The method comprises the following steps:

1. vacuum-coated (PVD, CVD) carrier layer 4

2. The barrier composite was prepared by bonding two coated carrier layers using a roll coating process, thereby producing adhesive layer 2'

3. The protective layer 1 is applied to the barrier composite 5 by means of multilayer extrusion coating, possibly with the aid of a hot melt adhesive, which is the adhesive layer 2.

Figure 3 shows an embodiment with a protective layer-barrier composite-carrier layer (extrusion lamination)

With barrier layer 4 (e.g. SiO)_x) A carrier layer 3 (for example PET) is applied. It is mixed with a second SiO_xThe coated carrier layers are joined by means of an adhesive layer 2' by means of a roll coating method. A protective layer 1 (e.g. a PMMA film or a co-extrusion of PMMA and polyolefin) is applied on this barrier composite 5 by extrusion lamination. For example, a hot melt adhesive (e.g. based on ethylene-acrylate copolymers) may be used as the adhesive layer 2 for such lamination. This hot melt adhesive is extruded in the melt state between the barrier composite 5 and the protective layer 1 using a die. The protective layer 1 is characterized in that it contains a UV absorber.

The method comprises the following steps:

1. vacuum-coated (PVD, CVD) carrier layer 4

2. The barrier composite was prepared by bonding two coated carrier layers using a roll coating process, thereby producing adhesive layer 2'

3. Extrusion lamination of an adhesive layer 2 in the melt state between a protective layer 1 and a barrier composite

Measurement of Barrier Properties of films according to the invention

The measurement of the water vapor transmission rate of the membrane system was performed according to ASTM F-1249 at 23 ℃/85% relative humidity.

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

Examples

Comparative example:

films according to the prior art (EP 1018166B 1), for example SiOx-coated ETFE with a layer thickness of 50 μm, have a density of 0.7 g/(m)²d) Water vapor transmission rate of (d).

The film according to the invention having a layer thickness of the barrier composite 5 of 50 μm has a value of 0.01 to 0.05 g/(m)²d) Water vapor transmission rate (see example 1).

Example 1

Protective layer 1: PMMA with a layer thickness of 50 μm and 1% UV absorber234。

Adhesive layer 2: 62% of Laromer UA 9048V, 31% of hexanediol dimethacrylate, 2% of hydroxyethyl methacrylate, 3% of Irgacure 651, 2% of 3-methacryloxypropyltrimethoxysilane

The barrier composite 5 is composed of the following layers:

carrier layer 3: PET Mitsubishi Hostaphan RN12, layer thickness: 12 μm.

Barrier layer 4: SiO applied by electron beam vacuum evaporation_1.5Layer thickness: 40 nm.

Adhesive layer 2': two-component system Liofol LA 2692-21 and curing agent UR 7395-22 from Henkel

Example 2

Protective layer 1: impact-resistant PMMA, layer thickness: 250 μm, 2% UV absorber CesaGXUVA006。

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

The barrier composite 5 is composed of the following layers:

carrier layer 3: PEN, layer thickness: 20 μm

Barrier layer 4: al (Al)₂O₃Layer thickness 40nm, applied using magnetron sputtering.

Adhesive layer 2': 60% Laromer UA 9048V, 30% hexanediol diacrylate, 2% hydroxyethyl methacrylate, 3% Irgacure 184, 2% butyl acrylate, 4% methacryloxypropyltrimethoxysilane

Example 3

Protective layer 1: co-extrusion of PMMA and impact-resistant PMMA with a layer thickness of 150 μm, containing 1.5% UV absorber360。

Adhesive layer 2: 62% Ebecryl 244, 31% hexanediol diacrylate, 2% hydroxyethyl methacrylate, 3% Irgacure 651, 2% Glymo

The barrier composite 5 is composed of the following layers:

carrier layer 3: PET, layer thickness 23 μm.

Barrier layer 4: SiO 2_1.7Layer thickness 80nm, applied using magnetron sputtering.

Adhesive layer 2': 70% hexanediol diacrylate, 17% pentaerythritol tetraacrylate, 5% methyl methacrylate, 2% Irgacure 184, 2% hydroxyethyl methacrylate, 2% methacryloxypropyltrimethoxysilane

Example 4

Protective layer 1: co-extrusion of impact-resistant PMMA (e.g. Plex 8943F) with a layer thickness of 40 μm, containing 1.5% UV absorber360 and polyethylene (e.g., Dowlex SC 2108G), layer thickness 200 μm. Adhesion promoter: dupont Bynel 22E 780 (ethylene acrylate copolymer).

Adhesive layer 2: dupont Bynel 22E 780

The barrier composite 5 is composed of the following layers:

carrier layer 3: PET Mitsubishi Hostaphan RN75, layer thickness 75 μm

Barrier layer 4: SiO 2_1.7Layer thickness 80nm, applied using electron beam vacuum evaporation.

Adhesive layer 2': two-component system Liofol LA 2692-21 and curing agent UR 7395-22 from Henkel

The% data in the examples are always weight%.

List of reference marks

1 protective layer

2 adhesive layer

Adhesive layer of 2' barrier composite 5

3 support layer

4 Barrier layer

5 Barrier composite

Claims (9)

1. Barrier film consisting of a weather-aging-stable protective layer and a barrier composite, wherein the protective layer is stable to weathering 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 in that it has a partial discharge voltage of at least 1000V.

4. Barrier film according to claim 1, characterised 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, characterised in that between the barrier composite and the protective layer there is an adhesive layer formed by an adhesion promoter having the following composition:

a) 1% to 80% by weight of mono-or polyfunctional acrylates or methacrylates

b) 0% to 30% by weight of a prepolymer

c) 0% to 48% by weight of acrylate or methacrylate containing siloxane groups

d)0.1 to 10 wt.% of at least one initiator

e) 0% to 10% by weight of at least one regulator

f) 0% to 40% by weight of customary additives.

6. The barrier film according to claim 1, characterized in that an adhesive layer formed of a hot melt adhesive is present between the inorganic barrier layer and the protective layer.

7. A method of making a barrier film characterized by

a) Providing a carrier film (polyolefin, polyester) with an inorganic coating by means of vacuum evaporation or sputtering and joining this film with another film having an inorganic coating by means of an adhesive layer and combining the film composite thus produced with a weathering-stable plastic film (PMMA, coextrudate of PMMA and polyolefin) by means of lamination, or

b) Providing a carrier film (polyolefin, polyester) with an inorganic coating by means of vacuum evaporation or sputtering and joining this film with another film having an inorganic coating by means of an adhesive layer and combining the film composite thus produced with a weathering-stable plastic film (PMMA, coextrudate of PMMA and polyolefin) by means of extrusion lamination, or

c) Providing a carrier film (polyolefin, polyester) with an inorganic coating by means of vacuum evaporation or sputtering and joining this film with another film having an inorganic coating by means of an adhesive layer and combining the film composite thus produced with a weathering-stable plastic film (PMMA, coextrudate of PMMA and polyolefin) by means of extrusion coating, and

d) SiO is evaporated by means of electron beams in the physical vacuum evaporation mentioned under 7a) to c), or

e) The SiO is thermally evaporated in the physical vacuum evaporation mentioned under 7a) to c).

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

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