DE102018108588A1 - Barrier layers and compositions for their preparation - Google Patents

Abstract

A composition is proposed which can be used to produce barrier layers or barrier coatings more cost-effectively than in the past, this composition comprising a polymer material, surface-modified platelet-shaped inorganic particles and a water fraction for the production of a barrier layer, the particles on their surface modified with one or more amino-functional components, wherein the particles have a nanoscale platelet thickness and wherein the polymer material comprises polyvinylidene chloride, cellulose derivatives, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polyurethanes, polyacrylates and / or mixtures thereof.

Description

The invention relates to a composition for the preparation of barrier layers, the use of the compositions according to the invention for the preparation of barrier layers, barrier layers made from the compositions according to the invention, substrates provided with a barrier layer and a method for applying a barrier layer to a substrate ,

Packaging and packaging made of various materials are of general importance, both for private and industrial use. In the simplest case, these packages and containers represent only containers.

In particular, when storing valuable, sensitive or dangerous goods they must be protected from environmental influences or generally against external influences. This can be realized in particular by additional protective layers or barrier layers, which are applied to the respective packaging and containers. An additional protection of valuable and sensitive goods, which often can not be done exclusively by a conventional packaging material, concerns above all a protection against environmental influences such as moisture, oxygen, light and temperature influences.

Especially for materials in the pharmaceutical, semi-luxury, chemical, computer and building materials industries, packaging and containers are used extensively with such additionally applied barrier layers.

As a result of the described aspects, there is thus an urgent and growing need for inexpensive and easy to apply barrier coatings for packaging and containers, which show good adhesion to the common packaging materials and in which the elastic properties and hardness are adjustable.

However, not only for use as a barrier coating on packaging and containers or foils, there is an increasing demand for improved barrier coatings, but also for the corrosion protection of metals, the barrier properties of the coating or applied conversion layers to oxygen, electrolytes and water are of elementary importance.

As barrier layers, by means of vacuum methods, for example by means of the so-called Physical Vapor Deposition (PVD), deposited metal layers, in particular PVD aluminum layers, have proven useful, which, however, often have to be protected against oxidation and corrosion themselves by applying organic coatings.

The use of PVD-coated films as packaging and for the protection of sensitive goods from oxygen and water vapor is widely known. The barrier effect of a vapor deposited thin metallic layer is very high.

Disadvantages, however, are the complex and expensive production processes in a high vacuum and the sometimes pronounced susceptibility of these layers to corrosion processes. Therefore, alternative barrier layers have already been recommended in the prior art for a number of applications.

In the CN 2015 76687 U are fluorine component-free films consisting of a base layer, an aluminum-metal interlayer and a protective layer with a high barrier to water vapor and other environmental factors, described for increasing the weather resistance of photovoltaic cells.

Coated aluminum foils are also used in the JP 2001 006631 A described as excellent gas and electrolyte barrier layers.

The US patent US 4,601,943 A also describes aluminum foils which have vapor barrier properties arranged between two plastic films and can thus be used as fire protection.

In the DE 101 52 266 C1 Coated water-soluble hollow bodies are described using water-soluble polymers with a coating of graphite, titanium and chromium nitride and carbonitride applied in the gas phase by means of chemical vapor deposition CVD.

The WO 2008/034733 A1 ( EP 2 069 210 B1 describes packaging containers with barrier layers of single or multi-layer arrangements including metal foils and metal layers, for example of aluminum, which are optionally combined with different layers of plastics, also in the form of composite films, the metal layers preferably using PVD methods on the Containers are applied. This multilayer arrangement may alternatively be obtained by a so-called multi-component injection molding.

Barrier layers consisting of organic film formers such as polyvinylidene chloride (PVDC) or ethylene-vinyl alcohol copolymers (EVOH) are also in use. However, the barrier effect of these polymer layers is not sufficiently high for most applications involving an oxygen barrier, and especially a water barrier. For the most part, these barrier layers are therefore combined with other metallic or oxidic barrier layers.

To improve the barrier effect, so-called hybrid materials have also been used. In the DE 196 50 286 A1 Inorganic-organic hybrid materials (ORMOCER layers) are described by way of example which show barrier properties, in particular on a support material already pre-coated with SiO _x . Experience has shown that these hybrid coatings for application are particularly well on polar, hydroxyl-containing and metallic surfaces, while on non-polar, eg polyolefinic surfaces, especially in flexible and / or elastic substrates (eg films, in particular packaging films), due to their hardness, brittleness or Lack of elasticity can not be used to produce a permanent barrier effect.

To achieve maximum effect in these hybrid material layers, therefore, a two-layer structure of a metallic or oxidic layer and a layer of the hybrid material is often necessary.

In the WO 01/66654 A1 and the WO 01/66655 A1 describes the use of condensation products of bis-aminomethoxysilane or other aminosilanes and phenolic compounds in methanol for the preparation of barrier layers.

In the WO 01/66656 A2 and the WO 01/66662 A2 For example, mixtures of bis-aminotrimethoxysilane and aminoethylaminopropyltrimethoxysilane with multifunctional acrylates and ethylenically unsaturated organic acids are described as UV-curable barrier layers.

The DE 103 50 125 A1 describes barrier layers for organosilane-based gases which comprise at least one organoalkoxysilane whose organo-functionality has at least one unsaturated hydrocarbon group, at least one aminoalkylalkoxysilane, at least one polyol and at least one co-condensate of said components. These barrier layers can be used to advantage in base-insensitive substrates such as polyolefins. Experience has shown, however, that certain substrate damage can occur, especially with thinner substrates made of polyesters or with a metal substrate due to the water content and, above all, due to the relatively high content of the coating composition of amino-functional silanes. Even with surface-modified thin platelet-shaped metal particles, due to the basic properties of these coating formulations, an increased susceptibility to corrosion and, as a result, damage to the metal platelets is to be expected when they are introduced into such basic barrier layer formulations.

However, the most important properties of barrier layers in addition to the barrier effect against the respective environmental influences are, above all, the robustness, flexibility and costs in the application process and the permanence of these coatings.

An essential role for the requirements of a barrier layer is played by the immense quantities of packaging and packaging produced in the industrialized nations as well as the worldwide pressure to reduce costs and increase productivity.

As already explained, according to the prior art, metal layers, mostly aluminum metal layers, are vacuum-deposited by means of PVD processes as barrier layers on a very wide variety of materials applied. These processes are on the one hand energy and cost intensive and on the other hand by the use of a vacuum process also not very flexible.

There is therefore a need for barrier layers which can be applied more simply and inexpensively, while still being able to provide a barrier effect, for example to oxygen and water vapor, of a similar order of magnitude as can be achieved with the barrier effect of a PVD layer of metal.

The object of the present invention is to propose a composition with which barrier layers or barrier coatings can be produced more cost-effectively, even for large quantities.

This object is achieved by a composition having the features of claim 1.

Production-related disadvantages of barrier coatings consisting of PVD metal layers are avoided by the present invention. The time-consuming, energy-consuming and ultimately expensive metal coating process in the established state of the art is replaced according to the present invention by an application of a liquid, water-based composition of coating components.

The compositions according to the invention can easily be applied to the substrates to be provided with a barrier coating, in particular also to films. It is particularly advantageous that the compositions according to the invention can also be formulated in such a way that they can be applied to the substrate as a layer by means of doctor blades or a printer.

In the context of the present invention, the term particles having "nanoscale platelet thickness" particularly includes platelet-shaped particles having an average thickness of about 200 nm or less, in particular about 100 nm or less, more preferably about 80 nm or less, and optionally about 60 nm or less.

The average thickness of the platelet-shaped particles can be determined manually by means of electron microscopy images.

According to the invention, the particles with nanoscale platelet thickness are modified on their surface with one or more amino-functional components.

In contrast to the described PVD methods in the prior art, the composition according to the invention can be applied on a substrate in a cost, time and energy efficient manner using conventional and generally accessible painting systems, by dipping or by printing.

Among the aspects mentioned is the universal applicability and adhesion of the composition of the invention and the coatings obtained therefrom on different substrates added. In addition, the hardness and the elastic properties of the barrier coating resulting according to the invention can be adjusted.

The polymeric material of the hydrous compositions of this invention include polyvinylidene chlorides, cellulose derivatives, polyvinyl alcohols, ethylene-vinyl alcohol copolymers, polyurethanes, polyacrylates, or mixtures thereof.

The cellulose derivatives are preferably partially esterified cellulosic materials, wherein the degree of substitution (DS), the average number of replaced hydroxy groups per glucose unit, preferably about 1 to about 3, in particular about 1 to about 2.

The polymer material preferably comprises a polymer and / or oligomer component which is free-radically and / or thermally curable. The aforementioned polymeric materials may already include this functionality if selected. For thermal curability, polymeric materials or components having isocyanate groups are preferred, for free-radical curability those having double bond-functional groups are preferred.

The nanoscale, platelet-shaped inorganic particles are preferably selected from metal, metal oxide, nitride and silicate-based platelet-shaped particles.

In particular, the platelet-shaped particles for the composition according to the invention are selected from aluminum and aluminum oxide particles, glass particles, aluminum silicate and silicate particles and also boron nitride particles.

Platelet-shaped metal particle-containing coatings of the invention not only produce a barrier effect against gases and moisture, but in particular also provide a protective effect against heat and UV radiation.

It has been found that even highly crosslinked two-component (2K) clearcoat materials alone can not provide sufficient barrier to gases. Therefore platelet-shaped fillers are used according to the invention to increase the barrier effect, for example talc or mica materials are added to the compositions according to the invention.

Due to the hydrophilicity of the inorganic platelets used, an increased water storage capacity of the coating is to be expected per se, so that the use of these materials would be subject to certain restrictions.

In view of this, the invention proposes that the platelet-shaped particles are modified on their surface with one or more amino-functional component (s) and optionally one or more double bond-functional reactive silane components, so that their hydrophilicity is optimized for the particular application.

In addition, these platelet-shaped materials have an optimum effect because they are compatible with the coating matrix due to surface modification and, more preferably, are chemically crosslinkable with the binder matrix.

More preferably, the platelet-shaped particles may optionally be additionally surface-modified with reactive epoxide-functional silane components, which applies in particular to metal and silicate particles.

The platelet-shaped particles are preferably selected from metal, metal oxide, nitride and silicate-based particles, and in particular selected from aluminum particles, aluminum oxide particles, glass particles, aluminum silicate particles, silicate particles and boron nitride particles ,

The amino-functional component for surface modification of the platelet-shaped particles is in particular selected from polyfunctional, low molecular weight aliphatic, aromatic and heterocyclic components, as well as amino-functional polyether components, 2-aminoethyl-3-aminopropyltrimethoxysilane and 3-aminopropyltrimethoxysilane or mixtures thereof.

The multifunctional low molecular weight aliphatic, aromatic or heterocyclic components typically have a molecular weight of about 600 g / mol or less, in particular about 500 g / mol or less.

Typically, the molecular weight is about 40 g / mol or more, although components with lower molecular weights can also be used according to the invention.

The optional double-bond-functional reactive silane component for surface modification of the platelet-shaped particles is preferably selected from the components vinyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane or mixtures thereof.

For the further optional epoxide-functional component for surface modification of the platelet-shaped particles, preference is given to the use of 3-glycidyloxypropyltrimethoxysilane.

The concentration of the surface-modified platelet-shaped particles according to the invention in the composition is preferably about 0.1 to about 60% by weight, in particular about 1 to about 40% by weight and further preferably about 1 to about 30 Wt .-%, based on the dye content of the polymer material.

In this case, the surface-modified platelet-shaped particles according to the invention preferably have an average platelet thickness of about 10 to about 200 nm, in particular from about 20 to about 100 nm and particularly preferably from about 20 to about 80 nm.

Good incorporation of the surface-modified particles into the surrounding matrix of the polymer material in a finished barrier coating does not necessarily require a direct chemical bond between the platelets or their modified surface and the polymer matrix. A good integration is also possible by the formation of strong and sufficient hydrogen bonds to the polymer matrix, as shown in the examples.

An aminofunctional surface modification of the particles according to the invention, as shown in the following Examples 1 and 2, gives particularly good results with respect to the barrier action against gases, such as, for example, in the aqueous compositions according to the invention with binder components having hydroxyl, amino and acid functionalities. Oxygen.

These aspects can now be taken into account in the barrier coating according to the invention by using as platelet-shaped particles reactive inorganic, surface-modified nanoscale platelet-shaped particles, in particular nanoscale layered silicate and aluminum platelets, which integrate chemically or via hydrogen bonds into the respective polymer network to let. In the case of a polar polymer matrix, incorporation preferably takes place via amino-functional surface modifications by forming strong hydrogen bonds, in the case of less polar and rather hydrophobic polymer networks preferably via a double bond-functional, in particular by means of olefinic groups, surface modification of the particles.

It also emerges from Example 2 that the strong interaction between the boric acid and borate components with the amino-functional surface modification of the particles can play a key role in network formation.

When using other known from the prior art crosslinking components, such as reactive siloxanes and so-called blocked isocyanates for so-called hydro varnishes, the achievable oxygen transfer rates (OTR values) were on average about the factor 5 elevated.

It is therefore preferred that the surface modifications according to the invention are used in water-containing formulations in combination with boric acid and its derivatives.

The water-containing compositions according to the invention which, in addition to the surface-modified barrier particles, comprise a hydroxide-functional polymer component and in particular different derivatives of boric acid, e.g. Boric acid and amines neutralized with borates, are therefore still preferred as barrier coatings.

The boric acid derivatives are preferably present in amounts of about 1 to about 10 wt .-%, more preferably about 3 wt .-% to about 8 wt .-% and particularly preferably about 4 wt .-% to about 6 wt .-%, based on the proportion of the hydroxide-functional polymer component, used in the compositions of the invention.

For the compositions according to the invention which comprise a polar polymer component, it has surprisingly been found that surface-modified platelet-shaped particles are preferred which contain surface coatings with high proportions of amino-functional components, preferably selected from a reactive amino-silane component and / or an organic amine low molecular weight, oligomeric or polymeric polyfunctional amino component, and optionally have a reactive epoxy silane component.

The water-containing barrier coating composition according to the invention furthermore preferably also comprises a hydroxyl-functional polymer component and derivatives of boric acid, the latter component preferably being used in the form of amines neutralized with boron.

The compositions according to the invention for generating a barrier layer or barrier coating against the permeation of gases, in particular oxygen, preferably furthermore comprise from about 0.2% by weight to about 8% by weight, preferably about 0.8% by weight about 6% by weight and more preferably about 1.5% by weight % to about 5.5 wt .-% of surface-modified nanoscale aluminum and / or silicate particles, based on the proportion of the polymer material in the composition.

The barrier coating or barrier layer ultimately obtained from the compositions according to the invention preferably has a dry layer thickness of about 0.1 to about 20 μm, in particular of about 0.5 to about 10 μm and more preferably of about 0.5 to about 5 microns and comprises a layer with amino- and double bond-functionally surface-modified platelet-shaped particles embedded in a preferably thermoset polymer matrix.

In the context of the present invention, dry film thickness is understood as meaning the layer thickness of a coating according to the invention after it has cured, as measured DIN EN ISO 139 (at a temperature of 23 ° C and a relative humidity RH of 50%) by means of the eddy current method according to DIN EN ISO 2808: 2004 in that the substrate is fixed on a suitable metal support without and with the superficially applied barrier coating. The difference of the values obtained then represents the dry layer thickness of the barrier coating.

Often the barrier effect to gases, e.g. Oxygen also has a certain barrier effect with respect to water or water vapor. Owing to the different behavior of the amino-functional surface-modified nanoscale platelet-shaped aluminum and silicate (talc) particles, it is often expedient to provide both particle types in admixture with one another in a barrier coating in order to optimize the barrier properties, as will be demonstrated with reference to Example 3.

According to a further embodiment of the invention, the actual barrier coating or barrier layer can be overcoated with one or more, possibly thicker, particle-free, in particular likewise thermosetting, coatings.

This embodiment of a multi-layer barrier coating or barrier layer according to the invention is particularly suitable for preventing the permeation of water, the barrier coating or barrier layer preferably having a superficial coating with a layer thickness of about 10 .mu.m to about 40 μm, in particular from about 15 μm to about 25 μm, a particularly particle-free clearcoat layer and an underlying about 0.5 μm to about 3 μm, in particular about 0.7 μm to about 1 μm thick, nanoscale thick platelets shaped particles, in particular aluminum particles containing layer is formed.

The underlying layer of the barrier coating or barrier layer for preventing the permeation of water preferably contains about 0.1 wt .-% to about 10 wt .-%, more preferably about 0.5 wt .-% to about 5 wt. -%, and most preferably about 0.5 wt .-% to about 3 wt .-% of the invention surface-modified nanoscale platelet-shaped particles, based on the proportion of the polymer material of the composition.

Further preferably, the barrier coating or barrier layer is colorless, dark or white formulated and has no metallic effects. This can be achieved by the additional use of white or black pigments, in which case the barrier coating can be formulated substantially neutral in color, dark or white, and further preferably has no visually striking metallic effects.

In principle, the barrier coating according to the invention can be used on different substrates, the application to plastics for packaging and containers being preferred.

The composition according to the invention can be used for the production of barrier coatings or barrier layers on substrates of all kinds.

In particular, it is used for the production of barrier coatings or barrier layers on metal, paper, cardboard and plastic substrates of all kinds and their combinations, in particular for the production of barrier coatings or barrier layers on plastic packaging and moldings of all kinds, further preferably on plastic cartridges and plastic Capsules, plastic films and plastic bottles, consisting of polyamide (PA), polyethylenes (HDPE, LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyacrylates (especially polymethyl methacrylate PMMA), polyesters (eg polyethylene terephthalate PET), Polylactides (PLA) and polycarbonate (PC) used.

However, it can also be used for corrosive protection of metal substrates such as aluminum alloys or steels and other ferrous materials.

Optionally, the barrier coating according to the invention is additionally overcoated with a thicker, relatively highly crosslinked thermosetting organic metal particle-free coating or is part of a multilayer coating, as is known per se in industrial and automotive coatings, for example.

It may be applied to metal and plastic surfaces as part of a multi-coat application and / or multiple coating, and more preferably it is applied on two opposite sides, for example on inner and outer sides of moldings or films.

The invention further relates to coated specimens, hollow bodies, flat substrates and films obtained by the use and application of the compositions according to the invention with a barrier coating or barrier layer according to the invention applied to the inner surface and / or outer surface.

• 1: Vergleich der erhaltenen Sauerstoffbarriere (OTR-Werte), bezogen auf eine Schichtdicke von 10 µm der mit den Wasser-haltigen Barriere-Referenz-Beschichtungen P21 (ohne Partikel), T-P22 (mit nicht modifizierten Talkum-Partikeln) und den erfindungsgemäßen Wasser-haltigen Barriere-Beschichtungen (T-P23 und T-P24) beschichteten LDPE-Folien;
• 2: Vergleich der erhaltenen Sauerstoffbarriere (OTR-Werte), bezogen auf eine Schichtdicke von 10 µm der mit den Wasser-haltigen Barriere-Referenz-Beschichtungen, P21 (ohne Partikel), A-P22 (mit nicht modifizierten Aluminium-Partikeln) und den erfindungsgemäßen Wasser-haltigen Barriere-Beschichtungen (A-P23 und A-P24) beschichteten LDPE-Folie; und
• 3 Vergleich der erhaltenen Sauerstoffbarriere (OTR-Werte) bezogen auf eine Schichtdicke von 10 µm der mit der Wasser-haltigen Barriere-Referenz-Beschichtung P21 mit den mit erfindungsgemäßen Barriere-Beschichtungen (T-P23, A-P23 und A-P23/T-P23) beschichteten LDPE-Folie.

The invention will be described in more detail with reference to the following examples and figures, without limiting these. Show it:

• 1 : Comparison of the obtained oxygen barrier (OTR values), based on a layer thickness of 10 μm, with the water-containing barrier reference coatings P21 (without particles), T-P22 (with unmodified talcum particles) and the water-containing barrier coatings according to the invention ( T-P23 and T-P24 ) coated LDPE films;
• 2 : Comparison of the obtained oxygen barrier (OTR values), based on a layer thickness of 10 μm, with the water-containing barrier reference coatings, P21 (without particles), A-P22 (with unmodified aluminum particles) and the water-containing barrier coatings according to the invention ( A-P23 and A-P24 ) coated LDPE film; and
• 3 Comparison of the obtained oxygen barrier (OTR values) based on a layer thickness of 10 μm with the water-containing barrier reference coating P21 with the barrier coatings according to the invention ( T-P23 . A-P23 and A-P23 / T-P23) coated LDPE film.

Example 1: Surface modification of platelet-shaped aluminum and talcum particles for use in aqueous compositions according to the invention

There are provided 100 g of distilled water and, provided in the respective recipe, polyetheramine (Jeffamine® D-400 Fa. Huntsman Corp.) solved.

1. a) eine wässrige Paste mit einem Gehalt von ca. 10 Gew.-% nanoskalig (im Mittel ca. 50 nm) dicken Aluminium-Partikeln (Decomet 1050/10, Fa. Schlenk Metallic Pigments GmbH) oder
2. b) nanoskalig (im Mittel ca. 80 nm) dicke Silikat(Talkum)-Partikel (Talc LP30 der LITHOS Industrial Minerals GmbH),

in einer solchen Menge dazugeben, so dass eine Partikeldispersion mit einem Anteil an Partikeln von ca. 5,0 Gew.-% entsteht.With stirring at 800 U / min (dissolver Fa. Getzmann) is / are provided to the water provided or the resulting aqueous polyetheramine within 5 min

1. a) an aqueous paste with a content of about 10 wt .-% nanoscale (average about 50 nm) thick aluminum particles (Decomet 1050/10, Fa. Schlenk Metallic Pigments GmbH) or
2. b) nanoscale (average about 80 nm) thick silicate (talc) particles (Talc LP30 from LITHOS Industrial Minerals GmbH),

in such an amount, so that a particle dispersion with a proportion of particles of about 5.0 wt .-% is formed.

Thereafter, the particle dispersion is homogenized for 30 min at room temperature while maintaining the stirring speed mentioned.

The proportions given below for X, Y and Z% by weight of the respective components for the surface modification of the particles are listed in Table 1 for the various formulations of Examples M1 and M2.

In the case that polyetheramine is used, its amount is such that a content of X wt .-% polyetheramine, based on the particle content is achieved in the particle dispersion (see Table 1).

Y% by weight of a reactive amino-functional silane component A and optionally Z% by weight of a reactive epoxide-functional silane component B are added to the homogenized particle dispersions, in each case based on the particle content of the particle dispersion. The silane component A and optionally the silane component B are dissolved, each time dissolved in 2 ml of distilled water, slowly added dropwise, the resulting mixture was stirred for 15 minutes and finally heated to 80 ° C.

After reaching the temperature of 80 ° C, the mixture for crosslinking the reactive silane component A and optionally the silane component B is kept at the temperature of 80 ° C for 30 min with stirring.

The particle dispersion is then cooled to room temperature while stirring, centrifuged and the particle content of the dispersion is adjusted again to 10% by weight with the addition of distilled water.

The particle dispersions thus obtained are in paste form and are subsequently used in the aqueous compositions according to the invention for the preparation of barrier layers according to the invention (Examples 2 and 3). Table 1 Components of the components for the surface modification of the nanoscale particles according to Examples M1 and M2 modifying components M1 M2 Jeffamine D400 [X% by weight / particle] 0.0 1.0 Silane Component A: DAMO (2-aminoethyl-3-aminopropyltrimethoxysilane) [Y% by weight / particle] 3.5 1.7 epoxide-functional silane component B: GLYMO (3-glycidyloxypropyltrimethoxysilane) [Z% by weight / particle] 0.0 0.8

Example 2: Barrier effect of a barrier layer against oxygen, obtained from a composition according to the invention

As reference systems for evaluating the compositions of the invention and barrier layers prepared therefrom, compositions containing unmodified aluminum and talc particles (Reference Examples A-P22 respectively. T-P22 ) as well as a particle-free composition ( P21 ) used.

For the preparation of the compositions of the present invention, an ethylene-vinyl alcohol copolymer (EVOH) (EXCEVAL AQ-4104, available from Kuraray Europe GmbH) in distilled water was first heated to 90 ° C. for 4 hours to provide a polymeric material. The amount of EVOH is calculated to give a 15% by weight EVOH solution into which the indicated amounts of the respective particulate dispersions in paste form are blended.

Shortly before application to the substrate (commercially available LDPE film, see below), to these mixtures, as indicated in Tables 2 and 3 below, based on 5.0 g of the aqueous 15% strength by weight EVOH solution 1, 40 g of a 2% strength by weight triethanolamine borate solution (97%, Aldrich) in distilled water and 0.5 g of a 2% strength by weight boric acid solution (99.97%, Aldrich), likewise in distilled water, added.

The resulting aqueous compositions according to the invention were then applied homogeneously to a 34 μm thick low density polyethylene LDPE film by means of a doctor blade application, dried for 10 minutes at room temperature and then cured for 20 min in a circulating air oven at 80 ° C. The barrier layers thus obtained on the LDPE film had a dry film thickness of about 10 μm.

The OTR values measured on these coated LDPE films are in each case as OTR / 23 ° C / 10 μm in the unit ml / m ² / day in the 1 and 2 shown. The OTR values were determined according to ISO 15105-1: 2007-10.

In the following Tables 2 and 3, the respective composition of the water-containing compositions according to the invention with the talcum particles modified according to the invention (M1, M2) ( T-P23 and T-P24 ) or aluminum particles ( A-P23 and A-P24 ) from Example 1, the non-pigmented aqueous Barrier-reference coating P21 (Barrier clearcoat), as well as the barrier reference coatings A-P22 and T-P22 containing the non-surface-modified talcum particles ( T-P22 ) or aluminum particles ( A-P22 ) are reproduced. TABLE 2 Aqueous compositions according to the invention with modified talcum particles and corresponding reference formulations Components of the composition P21 Reference sample without particles T-P22 reference sample with uncoated particles T-P23 sample with particles M1 T-P24 sample with particles M2 15% by weight aqueous EVOH solution [g] 5.0 5.0 5.0 5.0 2% by weight aqueous triethanolamine borate solution [g] 1.4 1.4 1.4 1.4 2% by weight aqueous boric acid solution [g] 0.5 0.5 0.5 0.5 Talc particles (untreated) Talc LP 30 [g] - 0.0375 - - Talcum particle M1 Talc LP 30 [g] * ⁾ - - 0.0375 - Talc particles M2 Talc LP 30 [g] * ⁾ - - - 0.0375 barrier coating OTR value at 23 ° C and 10 μm layer thickness [l / m ² / day] 288.6 34.5 26.5 57.5 *) The aqueous compositions of the invention containing talcum particles each contained 5% by weight of the talcum particles, based on the solids content of the EVOH used (EXCEVAL AQ-4104), corresponding to 0.0375 g of the pulverulent particles in the formulation. TABLE 3 Inventive aqueous compositions with modified aluminum particles and corresponding reference formulations and barrier coatings obtained therefrom Components of the composition P21 reference sample without particles A-P22 reference sample with uncoated particles A-P23 sample with particles M1 A-P24 sample with M2 particles 15% by weight aqueous EVOH solution [g] 5.0 5.0 5.0 5.0 2% by weight aqueous triethanolamine borate solution [g] 1.4 1.4 1.4 1.4 2% by weight aqueous boric acid solution [g] 0.5 0.5 0.5 0.5 Aluminum particle paste (10% by weight particle content) (untreated) Decomet 1050/10 [g] - 0.15 - - Aluminum particles M1 paste (10% by weight particle content) Decomet 1050/10 [g] * ⁾ - - 0.15 - Aluminum particles M2 paste (10% by weight particle content) Decomet 1050/10 [g] * ⁾ - - - 0.15 barrier coating OTR value at 23 ° C and 10 μm layer thickness [l / m ² / day] 288.6 0.7 2.8 0.4 *) The aqueous compositions according to the invention with aluminum particles contained in each case 2% by weight of the aluminum particles, based on the solids content of the EVOH used (EXCEVAL AQ-4104), corresponding in each case to 0.15 g of the 10% by weight particle preparations of Example 1.

The lower content of aluminum particles compared to the formulations with talcum particles was chosen because of the lower gassing stability of the aluminum particles used here in the aqueous composition according to the invention.

A corresponding occurring gassing of the aluminum particles with evolution of hydrogen would affect the compactness of the polymer layer and thus the barrier effect. Specially corrosion-stabilized aluminum barrier particles are therefore preferred for water-containing compositions according to the invention and can be used at higher levels in the composition.

In 1 are the for the individual water and talcum particle-containing barrier coatings and in 2 the measured for the individual water and aluminum particle-containing barrier coatings and related to a layer thickness of 10 microns oxygen permeability OTR (Oxygen Transmission Rate) shown. The measurement of the OTR values was carried out in accordance with Standard ISO 15105-1: 2007-10 , Compared to the obtained OTR values for the coated film, an OTR value of 3091 ml / m ² / day was determined for the uncoated LDPE film.

The results in the 1 and 2 show that, provided an optimized surface coverage of the barrier particles, in particular using according to the invention water-containing compositions with the highly polar binder compositions of ethylene-vinyl alcohol copolymer (EVOH), boric acid and borates in combination with amino-functional surface-modified talc particles ( 1 ) and / or aluminum particles ( 2 ) can achieve excellent barrier effects against oxygen permeation.

It has also been found that the strong interaction between the boric acid and borate components with the amino-functional surface modification of the particles is of particular importance.

Using other crosslinking components, such as reactive siloxanes and blocked isocyanates for water-based paints, the achievable OTRs were on average about a factor 5 elevated.

It is therefore preferred that the surface modifications according to the invention are used in water-containing formulations in combination with boric acid and its derivatives.

It has been found that even at relatively low levels of the surface-modified talcum particles ( 1 ) and in particular the aluminum barrier particles ( 2 ) have excellent barrier coatings to gases such as oxygen.

For the oxygen barrier effect in 1 Consequently, the following ranking of the water-containing barrier coatings according to the invention can be stated (ordered from higher to lower barrier effect) using silicate talcum particles: $$\begin{array}{lllllll}\mathbf{T}\text{-}\mathbf{<figure-callout\; id="2"\; label="P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">P</figure-callout>}23\hfill & >\hfill & \mathbf{T}\text{-}\mathbf{<figure-callout\; id="2"\; label="P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">P</figure-callout>}22\hfill & >\hfill & \mathbf{T}\text{-}\mathbf{<figure-callout\; id="2"\; label="P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">P</figure-callout>}24\hfill & >>\hfill & Referen\mathrm{<figure-callout\; id="2"\; label="z\; P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">z\; </figure-callout>}\mathbf{P}\mathbf{}21\hfill \end{array}$$

For the oxygen barrier effect in 2 as a result, the following ranking of the water-containing barrier coatings according to the invention can be stated (ordered from higher to lower barrier effect) using metallic aluminum particles: $$\begin{array}{lllllll}\mathbf{A}\text{-}\mathbf{<figure-callout\; id="2"\; label="P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">P</figure-callout>}24\hfill & >\hfill & \mathbf{A}\text{-}\mathbf{<figure-callout\; id="2"\; label="P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">P</figure-callout>}22\hfill & >\hfill & \mathbf{A}\text{-}\mathbf{<figure-callout\; id="2"\; label="P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">P</figure-callout>}23\hfill & >>\hfill & Referen\mathrm{<figure-callout\; id="2"\; label="z\; P"\; filenames="DE102018108588A1\_0004.png"\; state="\{\{state\}\}">z\; </figure-callout>}\mathbf{P}\mathbf{}21\hfill \end{array}$$

From the 1 and 2 It can thus be deduced that the lowest OTR values were achieved in each case with barrier coatings according to the invention ( T-P23 and A-P24 ).

The reference barrier coatings on the LDPE films formulated without particles give little effect as an oxygen barrier.

The LDPE slides in the 1 and 2 On the other hand, which have been coated with the barrier coatings according to the invention which contain the modified talcum and in particular the aluminum particles modified according to the invention, on the other hand show excellent oxygen barrier properties. The highest oxygen barrier settled with the barrier coating in 2 reach, which, according to the surface modification according to the invention M2 , amino- and epoxide-functional surface-functionalized aluminum particles.

Although the reference examples T-P22 and A-P22 in which the coatings contain uncoated particles, give similar OTR values as the inventive examples T-P23 and T-P24 on the one hand and A-P23 and A-P24 On the other hand, the examples according to the invention have considerable economic and technical advantages, since in particular a uniform distribution of the particles in the composition and the coatings produced therefrom can be achieved more simply and in particular more reliably and thus a reproducible product quality can be ensured with little effort.

The possibly slightly higher OTR values of some examples according to the invention are already more than compensated by the advantages in the processing of the formulations according to the invention. This is particularly important in the important application areas of packaging and containers of great importance.

In addition, the modification of the particles according to the invention achieves a reduction in their water storage capacity, which in a large number of applications is of considerable importance for the resulting gas barrier effect, if these very strongly humid conditions, e.g. an environment with a relative humidity (RH) of approx. 60% RH to 100% RH.

Example 3: Barrier effect of a barrier layer against oxygen, obtained from a further composition according to the invention

Often, a barrier effect to gases, e.g. Oxygen, not complete with a barrier to water or water vapor, especially at very high humidity. Due to the different behavior of amino-functional surface-modified nanoscale platelet-shaped aluminum and silicate (talc) particles, it is advantageous for some applications to use both types of particles in the form of a mixture in the barrier coating according to the invention. This also has the advantage that even at low levels of platelet-shaped aluminum particles, the barrier effect can be significantly improved without a - often desirable - transparency and color neutrality of the barrier layer is significantly impaired.

This will be clarified in the context of Example 3. In this case, platelet-shaped aluminum particles coated in accordance with the invention and also talcum particles are used at the same time as an otherwise unchanged coating composition compared with Example 2, as can be seen from Table 4. The test result regarding the OTR value is in 3 compared to a reference sample ( P21 ) as well as two samples according to the invention ( T-P23 and A-P23 ). TABLE 4 Inventive aqueous composition with modified aluminum particles and talcum particles and barrier coating obtained therefrom Components of the composition P21 Reference sample without particles T-P23 sample with particles M1 A-P23 sample with particles M1 A-P23 / T-P23 sample with particles M1 15% by weight aqueous EVOH solution [g] 5.0 5.0 5.0 5.0 2% by weight aqueous triethanolamine borate solution [g] 1.4 1.4 1.4 1.4 2% by weight aqueous boric acid solution [g] 0.5 0.5 0.5 0.5 Talcum particle M1 Talc LP 30 [g] * ⁾ - 0.0375 - 0.0225 Aluminum Particle M1 paste (10% by weight particle content) Decomet 1050/10 [g] * ⁾ - - 0.15 0.15 barrier coating OTR value at 23 ° C and 10 μm layer thickness [l / m ² / day] 288.6 26.5 2.8 1.0 *) The composition of the invention T-P23 contained 5 wt.% Talcum particles; the inventive composition A-P23 2-% by weight of aluminum particles and the inventive composition A-P23 / T-P23 a mixture of 3 wt.% talcum particles with 2 wt.% Aluminum particles, each based on the Solids content of the EVOH used (EXCEVAL AQ-4104). In each case, 0.15 g of the 10% by weight particle preparations were used in the formulation for the aluminum particles.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• CN 201576687 [0010]
• JP 2001006631 A [0011]
• US 4601943 A [0012]
• DE 10152266 C1 [0013]
• WO 2008/034733 A1 [0014]
• EP 2069210 B1 [0014]
• DE 19650286 A1 [0016]
• WO 0166654 A1 [0018]
• WO 0166655 A1 [0018]
• WO 0166656 A2 [0019]
• WO 0166662 A2 [0019]
• DE 10350125 A1 [0020]

Cited non-patent literature

• DIN EN ISO 139 [0065]
• DIN EN ISO 2808: 2004 [0065]
• Standard ISO 15105-1: 2007-10 [0096]

Claims (24)

A composition for the preparation of a barrier layer comprising a polymer material, surface modified platelet-shaped inorganic particles and a water content, wherein the particles are modified on their surface with one or more amino-functional components, wherein the particles have a nanoscale platelet thickness, and wherein the polymer material comprises polyvinylidene chloride, cellulose derivatives, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polyurethanes, polyacrylates and / or mixtures thereof. Composition after Claim 1 wherein the polymer material comprises a polymer and / or an oligomer component which is thermally and / or free-radically curable. Composition after Claim 1 or 2 wherein the platelet-shaped particles are additionally modified with one or more double bond-functionally reactive silane components and / or with one or more reactive epoxide-functional silane components. Composition according to one of Claims 1 to 3 , wherein the platelet-shaped particles are selected from metal, metal oxide, nitride and silicate-based particles and mixtures of these particles, and are preferably selected from aluminum particles, alumina particles, glass particles, aluminum silicate particles, silicate Particles and boron nitride particles, with mixtures of aluminum and silicate particles being particularly preferred. Composition according to one of Claims 1 to 4 in which the amino-functional component for the surface modification of the particles is selected from polyfunctional low molecular weight aliphatic, aromatic and / or heterocyclic components, amino-functional polyether components, 2-aminoethyl-3-aminopropyltrimethoxysilane and 3-aminopropyltrimethoxysilane and mixtures thereof. Composition according to one of Claims 3 to 5 in which at least one double-bond-functional reactive silane component is an olefinically reactive silane component, which is preferably selected from vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane and mixtures thereof. Composition according to one of Claims 3 to 6 wherein the epoxide functional component is a 3-glycidyloxypropyltrimethoxysilane. Composition according to one of Claims 1 to 7 wherein the proportion of the platelet-shaped particles in the composition about 0.1 wt .-% to about 10 wt .-%, in particular about 0.5 wt .-% to about 5 wt .-% and more preferably about 0.5 wt .-% to about 3 wt .-%, based on the proportion of the polymer material. Composition after Claim 1 to 7 wherein the platelet-shaped particles comprise a mixture of aluminum and silicate particles, wherein the proportion of platelet-shaped aluminum particles based on the proportion of the polymer portion of the composition about 0.1 wt .-% to about 6 wt %, in particular 0.1 wt .-% to about 2 wt .-% is and wherein the proportion of silicate particles based on the proportion of the polymer content of the composition about 0.1 wt .-% to about 8 Wt .-%, in particular 0.1 wt .-% to about 5 wt .-% is. Composition according to one of Claims 1 to 7 wherein the composition for generating a barrier effect against the permeation of gases, in particular oxygen, about 0.2 wt .-% to about 8 wt .-%, preferably about 0.8 wt .-% to about 6 wt % and more preferably about 1.5 wt .-% to about 5.5 wt .-% surface-modified aluminum and / or silicate particles comprises, based on the proportion of the polymer material. Composition according to one of Claims 1 to 10 wherein the platelet-shaped particles have an average thickness of about 10 nm to about 200 nm, preferably from about 20 nm to about 100 nm, and more preferably from about 20 nm to about 80 nm. Composition according to one of Claims 1 to 11 wherein the platelet-shaped particles comprise metal particles which are preferably corrosion-modified platelet-shaped aluminum particles. Composition according to one of Claims 1 to 12 in which the polymer material comprises a hydroxide-functional polymer component, boric acid and / or a derivative of boric acid, the boric acid derivative preferably being present as boric acid neutralized with amines, the boric acid and the boric acid derivative preferably being used in amounts of approximately 1% by weight. to about 10 wt .-%, more preferably about 3 wt .-% to about 8 wt .-% and most preferably about 4 wt .-% to about 6 wt .-%, based on the proportion the hydroxide-functional polymer component contained in the composition. Barrier coating obtained from a composition according to one of Claims 1 to 12 , with a layer having a dry film thickness of about 0.1 μm to about 10 μm, in particular from about 0.5 μm to about 5 μm and more preferably from about 0.5 μm to about 3 μm, wherein the surface-modified platelet-shaped particles are embedded in the barrier layer in a polymer matrix formed by the polymeric material. Barrier coating after Claim 14 , wherein the layer is thermally and / or UV-crosslinked. Barrier coating after Claim 14 or 15 wherein the barrier coating comprises one or more particle-free, preferably thermoset layers having a layer thickness of about 0.5 μm to about 25 μm, preferably of about 0.5 μm to about 5 μm. Barrier coating according to one of Claims 14 to 16 in which the barrier coating additionally has on one surface of the layer an about 0.5 μm to about 25 μm thick, preferably particle-free lacquer layer, the underlying barrier layer having a thickness of about 0.5 μm to about 3 μm, in particular of about 0.7 microns to about 1 micron, and in particular comprises aluminum particles or mixtures of aluminum and silicate particles. Barrier coating after Claim 17 wherein the barrier layer contains about 0.1 wt.% to about 10 wt.% of surface-modified platelet-shaped particles, based on the proportion of polymer material. Barrier coating according to one of Claims 14 to 17 wherein the barrier layer comprises about 0.1 wt.% to about 3 wt.% of surface-modified aluminum particles and about 0.1 wt.% to about 6 wt.% of surface-modified silicate particles. Barrier coating according to one of Claims 14 to 19 wherein the layer comprises additional white or black pigments and in particular is colorless white or dark formulated and more preferably is substantially free from metallic effects. Use of a composition according to one of Claims 1 to 13 for producing a barrier coating on a substrate, in particular for producing a barrier coating on metal, paper, cardboard and plastic substrates and combinations thereof, in particular for producing a barrier coating on plastic packaging and moldings, more preferably on plastic cartridges and plastic capsules , Plastic films and plastic bottles, based on polyamide (PA), polyethylene (HDPE, LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyacrylate, polyesters, polylactide (PLA) and polycarbonate (PC). Use after Claim 21 in that at least one of a plurality of mutually different layers and / or a plurality of identical layers are produced from the composition, preferably on a metal or plastic surface and more preferably on two opposite sides of a substrate, for example on inner and outer sides of a shaped article or a film. With a barrier coating coated substrate in the form of a shaped body, in particular a hollow body, a surface substrate, in particular a film, with an internally and / or externally applied barrier coating according to one of Claims 14 to 20 , A method of coating a substrate with a barrier coating comprising the steps of: providing a composition according to any one of Claims 1 to 13 ; and - applying the composition to the substrate surface by means of doctoring or a printing process; wherein the substrate is preferably a film, in particular a packaging film.

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