CA2085494A1 - Process for producing substrates containing a coating layer - Google Patents

Abstract

Abstract Process for producing substrates containing thermoplastic plastics and a coating layer of inorganic compounds. The coating layer is produced by vaporising inorganic materials from vaporiser crucibles in vacuum at pressures of less than 10-1 mbar, and the vapour of the inorganic materials is produced in a chamber surrounding the vaporiser crucible and the substrate and precipitated on the substrate. The coating layer may thus contain at least two metal and/or semi-metal compounds deposited directly on the thermoplastic plastic at the same time.
The inorganic materials in the vaporiser crucible are present at an apparent density which is 25 to 75 % of the true density.

Description

Process for Producina substrates containinq a coatinq laYer The invention relates to a process for producing substrates containing thermoplastic plastics and a coating layer of inorganic compounds, wherein the coating layer is produced by vaporising inorganic materials from vaporiser crucibles in vacuum at pressures of less than 10~1 mbar, wherein the vapour of inorganic materials is produced in a chamber surrounding the vaporiser crucible and the substrate, and the vapour of inorganic materials is precipitated on the substrate.

The invention also relates to substrates produced by the process of the invention.

The invention furthermore relates to the use of the substrates produced by the present inventive process.

It is known to apply silicon oxide to transparent plastic material by means of vacuum vapour-deposition or by sputtering and to produce a transparent container from this plastic material, for example in the form of a laminated film (EP 0 187 512).

It is known from EP 0 062 334 to provide flexible polymer films with vapour-impermeable coatings. The coatings consist of two layer portions, a first adhesion-promoting layer and a second barrier layer. Two differ~nt layer portions mean, for example double the manufacturing effort for the layers.

The application of such thin oxide layers effects a strongly reduced gas penetration of coated plastic films of this type. For example when packaging perishable 2 ~

goods, such as foodstuffs and luxury goods, it is possible for air and hence oxygen or water vapour, or moisture to penetrate the packaging, or aromatic substances, moisture or gases under pressure, such as for example carbon dioxide, may emer~e from a package through the packaging material to the surroundings.

This undesirable mass transfer may be reduced by means of barrier layers or blocking layers, such as for example metal films or plastic films with barrier properties, such as polyvinylidene chloride, or by means of silicon oxide layers.

Also transparent packaging materials are required increasingly, a burden which cannot be discharged using metal films. Barrier layers of plastic and metal often disturb the purity of type of the packaging materials and plastics may also produce undesirable chlorine contents in the packaging material.

Silicon oxide layers for example are as yet incapable of being convincing with regard to the colour. The silicon oxide layers per se are more or less transparent, but often have a colouration, for example yellowish. If such layers are transparent, the barrier effect is inadequate.
When inspecting the packaging, undesirable false impression~ of colour are given to the contents of the package. The permeability of gases and water vapour in known packaging material with o~ide layers is also inadequate. Packaging, for example of foodstuffs, must also withstand the sterilisation conditions. An oxide layer should not chip off under such conditions or develop weakening properties on a film or in a film composite.

European patent application 0 460 796 describes improved silicon oxide coatings on polymer substrates by "dopingl' 2 ~

siO2 with one or more metals. However, this measure cannot remove one disadvantage, namely spraying the crucible contents as a result of the energy supplied and the heat of vaporisation thus produced. The substrate may be damaged by spraying the crucible contents.

The object of the present invention is to make available a novel process for producing substrates, which makes it possible to overcome the said disadvantages and to provide a packaging material which shows no absorptions of any kind in the visible light range and which is completely transparent, shows low gas and water vapour penetration and in particular oxygen penetration, has layers which adhere firmly to one another and can be produced inexpensively and without flaws.

This is achieved in accordance with the invention in that the inorganic materials are present in the vaporiser crucible at an apparent density which is 25 to 75 % of the true density of the inorganic materials.

The inorganic layers are advantageously present in the vaporiser crucible as filling, tapping, moulding, bulk, packing, sinter or foam compositions.

The inorganic materials are also advan*ageously present as sinter compositions at an apparent dPnsity which is 25 to 75 % o~ the true density of the inorganic materials.

The apparent density is preferably 40 to 6~ %, and in particular 50 %, of the true density of the inorganic materials.

One single inorganic material or two or more inorganic materials next to one another or as a mixture may be used.

2 ~ 4 In a further advantageous embodiment of the process, at least two inorganic ma~erials are Yaporised in vacuum at the same time with formation of a vapour mixture, and the vapour mixture of the inorganic materials is precipitated directly onto the thermoplastic plastic of the substrate.

Processes in which two inorganic materials are vaporised in vacuum at the same time with formation of a vapour mixture are preferred.

Processes of the present invention are also preferred, wherein two different metals, semi-metals, metal and/or semi-metal compounds, as inorganic materials, are vaporised in vacuum at the same time with formation of a vapour mixture.

Preferred inorganic materials are the metals and semi-metals silicon, aluminium, magnesium, lanthanum, titanium, boron and zirconium, and preferred metal and semi-metal compounds are the oxides, carbides and nitrides of silicon, aluminium, magnesium, lanthanum, titanium, boron and zirconium. The inorganic materials may be present as a mixture in one or more vaporiser crucibles or each material may be present on its own in one or more vaporiser crucibles.

Processes of the present invention are preferred, in which two meta} and/or se~i-metal compounds are used as inorganic materials, wherein one compound is an oxide of silicon and at least one further compound is an oxide of aluminium, magnesium, lanthanum, titanium, boron or zirconium.

SiO2 and Al203 or SiO2 and MgO or SiO2 and La203 or SiO2 and TiO2 or SiO2 and ZrO2 or SiO2 and B203 are particularly preferably vapour-deposited at the same time.

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In a further preferred embodiment of the present invention, the substrate is bombarded with N2, Ar or 2 ions during vaporisation of the inorganic materials.

A process is also preferred, wherein the vaporisation and precipitation takes place in a reactive atmosphere.

At least 30 wt.% of SiO2 is advantageously present in the vaporiser crucible or crucibles.

50 to 95 wt.~ of SiO2 and 50 to 5 wt.% of Al203 or 50 to 9g wt.~6 of SiO2 and 50 to 1 wt.% of MgO or 50 to 95 wt.%
of SiO2 and 50 to 5 wt.% of La20~ or 50 to ~9 wt.g~ of SiO2 and 50 to 1 wt.% of TiO2 or 50 to 90 wt.% of SiO2 and 50 to 10 wt.% of ZrO2 or 70 to 99.99 wt.% of SiO2 and 30 to 0.01 wt.% of B203 are particularly advantageously present in the vaporiser crucible or crucibles.

50 to 80 wt.% of SiO2 and 50 to ~0 wt.% of Al203 or 80 to 99 wt.% of SiO2 and 20 to 1 wt.% of MgO or 50 to 80 wt.%
of SiO2 and 50 to 20 wt.% of La2O3 or 80 to 90 wt.~ of SiO2 and 20 to 10 wt . % of TiO2 or 50 to 70 wt.% of SiO2 and 50 to 30 wt.% of ZrO2 or 80 to 99.99 wt.% o SiO2 and 20 to 0.01 wt.% of B2O3 are pre~erably present in the vaporiser crucible or crucibles.

It is also possible to in~roduce, for example at least 30 wt.%, preferably 50 and more wt.%, and in partlcular 90 and more wt.%, of SiO2, and at least one metal and/or semi-metal, for e~ample Al, Mg, La, Ti~ Zr or B, preferably aluminium.

The introduction of glasses, such as for example low-alkali borosilicate glasses, for example containing about 30 wt.% of boron oxide in addition to SiO2, is also preferred.

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The introduction of 99 to 99.99 wt.% of sio2 and 1 to 0.01 wt.% of aluminium is advantageous.

Compounds of the formula SiO~, wherein x is, for example a number from 1 to 2, preferably 1.1 to 1.9, and particularly preferably 1.3 to 1.7, may also be used instead of SiO2.

According to the embodiment of the invention, the metals, semi-metals, metals and/or semi-metal compounds are vapour-deposited on the substrate from the same atmosphere, wherein the metals, semi-metals, metal andJor semi-metal compounds are present alone or as a mixture in the vaporiser crucible in a first embodiment.

kccording to a second preferred embodiment, the metals, semi-metals, metal and/or semi-metal compounds may be vapour-deposited on the substrate from the same atmosphere, wherein at least two metals, semi-metals, metal and/or semi-metal compounds are each introduced , individually in each case in a separate crucible.
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According to the present invention, the metals, semi-metals, metal and/or semi-metal compounds have an apparent density which corresponds to 25 to 75 % of the true density.

Apparent densities of this type are, for example the bulk or filling densities from loosely filled powder or powder, grains or fibres poured in a certain manner to form heaps in the crucible. If this filling density is not reached by loosely filling, the powder, the grains or fibres may be stored more tightly by tapping, so that the required tapping density is achieved. The required moulding density may also be achieved by applying moulding pressure to the heap of powder, grains or fibres. For example moulding pressures of 1 to 100 kg/cm2 and advantageously of 40 to 60 kg/cm2 may be applied.

Such a filling material ~or the vaporiser crucible may be produced, ~or example by bringing the appropriate inorganic materials to a grain size of 0.~5 to 1,000 ~m, for example by precipitation, crystallisation, milling, agglomeration or filtering. The inorganic materials may then be mixed cold and dry and mixed and moulded as a heap or, with or without binder, such as for example polyvinyl alcohol or polyvinylacetate, placed as a moulded body in a vaporiser crucible.

The compounds may also be produced by dissolving or gelling in strong mineral acids, mixing and precipitating, for example by the sol-gel process, drying and shaping in the vaporiser crucible.

Other processes for producing the filling material for the vaporiser crucible from the metals, semi-metals, metal and/or semi-metal compounds are, for example isostatic uniaxial moulding, extruding or slip casting of the appropriate powder mixture. The appropriate materials may also be molten together and then cast in appropriate moulds or atomised or sprayed.

In order to achieve the required apparent densities, particularly when they are sinter densities, the filling material may also be mixed with, for example organic components which volatilise duriny drying and/or sintering by vaporisation or combustion and leave cavities. Alternatively heaps or moulded bodies may be sintered to the required density.

Foam compos1tions can be obtained by impregnating an organic foam with the filling material, wherein the - B -filling material is introduced in slip form, drying the slip on the organic foam and baking the organic foam, wherein the filling material remains in the form of an image of the organic foam.

It i9 also possible to produce foam compositions by means of propellents which are added to the filling material.

If metals, semi-metals or compounds thereof are used individually as filling material, they may be processed in the same manner as filling material to form the required cruoible contents at the re~uired apparent densities.

To carry out the process of tha invention, the vaporiser cruciblec are introduced into a device for depositing layers from the gas phase onto a substrate. As a rule devices of this type have a vacuum chamber, a receiving device for at least one crucible and a receiving device for the substrate.

The contents are heated either directly by means of an electron beam or a plasma and/or the crucible is heated inductively by means of a resistance heater, by means of an electron beam and/or a plasma to vaporise the crucible contents. Depending on the mixture used, the crucible contents are vaporised at temperatures from 1,100 to 2,000C. The gas phase thus produced has in most cases a composition which is considerably different from the contents in the crucible itself. This also produces layers deposited from the gas phase with considerably altered compositions. The mixing ratios of the crucible contents given l~ad to the coating layer compositions of the invention.

Gas mixtures which lead to corresponding coating layer compositions may also be produced by sputtering in the gas phase of a target (target = crucible contents) with a composition corresponding approximately to the gas phase composition. Furthermore, corresponding mixed layers may be deposited by means of plasma-assisted CVD processes.

The deposition of the layers from the gas phase takes place on a substrate which is either at earth potential or has a negative or positive potential difference compared to the surroundings. The deposition takes place in vacuum, wherein as a rule the reduced pressure is less than 10-1 mbar and advantageously less than 10-3 mbar.

The vapours produced from the inorganic materials are precipitated, for example as such on the substrate. The vapours of the inorganic materials may be reacted by means of a reactive radical atmosphere to form novel or further compounds and the vapours of the materials or compounds, which are at least partly reacted, are also precipitated on the substrate.

The deposition may be carried out in a reactlve radical gas atmosphere, for example at reduced pressure of less than lo-3 mbar. The radical gas atmosphere may be formed by nitrogen, oxygen, water vapour, hydrocarbons, such as acetylene, and the like.

The vaporised inorganic materials may be reacted as a result of the reactive radical atmosphere, for example metals to their oxides (using oxygen) or to their carbides (for example using acetylene~, or oxides may be reacted, for example to give carbides.

The substrate may be bombarded with ions from an ion source before andtor during and/or after deposition. The substrate is preferably bombarded with N2, Ar or 02 ions during vaporisation.

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The preferred coating source is an electron beam vaporiser, in which a crucible is used, the length of which (for example about 1 m to 2.5 m) is greater than the width (for example about 0.8 m to 2.2.m) of the substrate passed over the crucible. One or more electron beam guns scan this crucible, wherein electrons in the electron beam guns pass through an acceleration voltage of, for example 30 to 40 kV. The power to be introduced per metre of crucible thus lies in the range from 35 to 100 kW. This power leads, for example to a layer thickness of about 60 nm, at a substrate conveying rate of about ~00 m/minute.

The process of the invention may be carried out, for example on fixed or continuously moving substrates.

The substrate surface facing the vaporiser crucible may optionally be cleaned first of all and activated to aim for further improvement in layer adhesion and the resistance capability thereof.

Cleaning and activat.ion make take place, for example by means of a plasma pretreatment.

In a continuous process the substrate may be guided being supported or guided freely and may be guided through the vacuum chamber at a rate ~f, for example 1 to 10 m/second and in particular 3 to 6 m/second.

Materials containing thermoplastic plastics are particularly suitable as su~strates.

The substrates may be cast, extruded or film-like materials. The materials may be rigid, semi-rigid or flexible.

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Examples o~ film-like materials which may be mentioned are films, laminates, composites or layered materials.
The film-like materials are usually flexible.

The substrates or film-like materials may contain thermoplastic plastics, for example thermoplastics based on olefin, based on ester, based on polyamide or halogen-containing plastics, also polyacetals, polyacrylates, polyarylenesulphides, polyarylenesulphones, polyarylene carbonates, polycarbonates, polyimides, polystyrenes or mixtures thereof, or may consist thereof. In particular, the surfaces of the film-like materials to be coated may contain the said plastics or consist thereof.

Examples of thermoplastics based on olefin are polyolefins, such as polyethylene, for example high density polyethylene (HDPE, density greater than 0.944 g/cm3), moderate density polyethylene (MDPE, density 0.926-0.940 g/cm3), linear moderate density polyethylene (LMDPE, density 0.926-0.940 g/cm3), low density polyethylene LDPE, density 0.910-0.925 g/cm3) and linear low density polyethylene (LLDPE, density 0.916-0.925 g/cm3), polypropylene, cast polypropylene, atactic or isotactic polypropylene or mixtures thereo~, amorphous or ~rystalline polypropylene or mixtures thereof, poly-l-butene, poly-3-methylhutene, poly-4-methylpentene and copolymers or coextrudates thereof, and ionomer resins, such as for example of polyethylene with vinyl acetate, acrylic acid, methacrylic acid, acrylic esters, tetrafluoroethylene or polypropylene, and random copolymers, block copolymers or olefin polymer-elastomer mixtures.

Examples of thermoplastics based on ester are polyalkylene terephthalates or polyalkylene isophthalates having alkylene groups or radicals with 2 to 10 carbon atoms or alkylene groups having 2 to 10 C atoms which are 2 ~

interrupted by at lea~t one -O-, such as for example polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate (polytetramethylene terephthalate), polydecamethylene terephthalate, poly-1,4-cyclohexyldimethylol terephthalate or polyethylene-2,6-naphthalene dicarboxylate or polyalkylene terephthalate and polyalkylene isophthalate mixed polymers, wherein the portion of isophthalate i~, for example 1 to 10 mole %, mixed polymers and terpolymers, as well as block polymers and grafted modifications of the materials mentioned above.

Polyalkylene terephthalates having alkylene groups or radicals with 2 to 10 carbon atoms and polyalkylene terephthalate~ having alkylene groups or radicals with 2 to 10 carbon atoms which are interrupted by one or two -O-, are advantageous thermopla~tics based on ester.

Polyalkylene terephthalates having alkylene groups or radicals with 2 to 4 carbon atoms are preferred thermoplastics based on ester, and polyethylene terephthalates are most particularly preferred.

Examples of thermoplastics based on amide include polyamide 6, a homopolymer of ~-caprolactam (polycaprolactan); polyamide 11, a polymer of 11-aminoundecanic acid (poly-ll-aminoundecanamide);
polyamide 12, a homopolymer of ~-lauric lactam (polylauric lactam); polyamide 6,6, a homopolymer of hexamethylene diamine and adipic acid (polyhexamethylene adipamide); polyamide 6,10, a homopolymer of he~amethylene diamine and sebacic acid (polyhexamethylene sebacamide); polyamide 5,12 a homopolymer of hexamethylene diamine and dodecanic diacid (polyhexamethylene dodecanamide) or polyamide 6-3-T, a homopolymer of trimethylhexamethylene diamine and 2 ~ 9 ~

terephthalic acid (polytrimethylhexamethylene terephthalamide), and mixtures thereof.

An incomplete list of halogen-containing plastics contains, for example the polymers of vinyl chloride and vinyl plastics containing vinyl chloride units in their structure, for example copolymers of vinyl chloride with vinyl esters of aliphatic acids, in particular of vinyl acetate; copolymers o~ vinyl chloride with esters of acr~lic acid and methacrylic acid and with acrylonitrile;
copolymers oi` vinyl chloride with diene compounds and unsaturated dicar~oxylic acids or anhydrides thereof, such as copolymers of vinyl chloride with diethylmaleate, diethylfumarate or maleic anhydride, rechlorinated polymers and copolymers of vinyl chloride; copolymers of vinyl chloride and vinylidene chloride with unsaturated aldehydes, ketones and others, such as acrolein, crotonaldehyde, vinylmethylketone, vinylmethylether, vinylisobuylether and the like; polymers of vinylidene chloride and copolymers o~ the same with vinyl chloride and other polymerisable compounds; polymers of vinylchloroacetate and dichlorovinylether, chlorinated polymers of vinyl acetate, chlorinated polymeric esters of acrylic acids and alpha-substituted acrylic acids;
polymers of chlorinated styrenes, for example dichlorostyrene, chlorinated rubber, chlorinated polymers of chlorobutadiene and copolymers thereof with vinyl chloride; rubber hydrochlorides and chlorinated rubber hydrochlorides; and mixtures of said polymers with one another or with other polymerisable compounds, and also the correspondin~ bromides and fluorides.

The film-like materials ma~ also be produced from or with cellulose-containing materials, such as paper, card, cardboard, paper-containing moulding compositions and the like, or may be strengthened with the aid of such materials.

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The thickness of the individual plastic film as a monofilm or of the individual plastic films in film composi-tes or laminates may be, for example 4 to 2,000 ~m, preferably 6 to 600 ~m, and in particular 6 to 150 ~m.

Film composites or laminates may have the layered structures known per se, such as for example containing at least two plastic layers, or containing at least one cellulose-containing layer and at least one plastic layer.

The film~like materials may also contain a sealing layer known per se, for example polyethylene, LLDPE, LDPE, MDPE, HDPE, polypropylenes, cast polypropylene, polyethylene terephthalate and heat-sealing lacquers, on at least one external side. Sealing layers of this type may also be provided with a coating layer of the invention.

All substrates may be used whether glass-clear, cloudy, ` evenly coloured, covered with colour or printed.

The composites and laminates, as mentioned in the present description, may be produced in a manner known per se, for example by coating, extrusion-coating, coe~trusion coating, laminating, counter-laminating or hot calendering.

The dif~erent layers and in particular the plastic films or layers with respect to one another, may be processed with one another to form laminates or composites using laminating a~hesives and/or adhesion promoters and optionally size.

The materials and processes for producing laminates and layered materials are known per se.

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The coating layer applied to the substrate by vaporising metal and/or semi-metal compounds, may have a thickness, for example of 5 to 500 nm, advantageously lO to 200 nm, and preferably 40 to 150 nm.

The coating layer may be applied to a substrate, such as for example to a film or a film composite, and occasionally a further film or a further film composite, for example of the same or similar construction to the substrate, may be applied to the coating layer. For example several coated substrates may be bonded to one another to produce substrates with several barrier layers. Other combinations are also possible, for example the mutual bonding of two coated substrates with the coating layers next to one another.

It is advantageous to apply at least one film or a film composite of thermQplastic plastics to the coating layer of a substrate. The substrate may also be coated with further films or film composites on the uncoated side.
Examples of films and film composites may be taken from the present description of the substrates and film-like materials.

The prese~t invention also includes the subs$rates produced by the process of the invention, containing thermoplastic plastics and a coating layer of inorganic compounds, wherein the coating layer has at least two metal andJor semi-metal compounds deposited directly on the thermoplastic plasti~ at the same time, ~ontaining a mixture of SiO~ and Alz03 or of SiO~ and MgO or of SiO~ and La203 or of SiO~ and TiO2 or of SiO~ and ZrO2 or of SiO~ and B203, wherein x means a numbPr from 1 to 2 and Si~ is present in the mixture at 50 to 99.99 atom ~.

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The substrates advantageously contain a coating layer of a mixture of at least two metal and/or semi-metal compcunds from the series of oxides, carbides and nitrides of silicon, aluminium, magnesium, lanthanum, titanium and zirconium, deposited at the same time.

The substrates preferably contain a coating layer of a mixture of two metal and semi-metal compounds deposited at the same time.

Advantageous substrates are those in which the coating layer contains two metal and/or semi-metal compounds of the general formula Si~ zMzO2 ~ 2N~C~

deposited at the same time, wherein a and ~ mean a number from O to 0.1, M has the meaning of Al, B, Mg, La, Ti or Zr and when M has the meaning Mg, z is a number from 0.001 to 0.5, or M has the meaning Ti, z is a number from 0.001 to 0.1, or M has the meaning B, z is a number from 0.001 to 0.4, or M has the meaning La, z is a number from 0.001 to 0.1, or M has the meaning Zr, z is a number from 0.001 to 0.1, or M has the meaning Al, z is a number from 0.001 to 0.1.

In the said general formula, M preferably has the meaning My, Ti, B, La, Zr or Al and z is a number from 0.001 to 0.1.
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- Substrates containing a coating layer of a mixture o~ SiO
and Alz03, or of SiOl and MgO or of SiOs and La203 or of SiO~ and TiO2 or of SiO~ and ZrO2 or of SiOs and B203, wherein x means a number from 1 to 2, are preferably present.

2 ~ 9 ~ -Substrates which contain a coating layer of a mixture of at least one metal and/or semi-metal compound and 50 to 99.99 atom ~ of SiO~, wherein x is a number from 1 to 2, are particularly preferred.

x in the formula SiOs preferably in each case means a number from 1.1 to 1.5, and in particular from 1.3 to 1.7.

Substrates which contain a coating layer of a mixture of two metal and/or semi-metal compounds and the coating layer contains a mixtura of 80 to 99.99 atom % of SiO~ and 20 to 0.01 atom % of Al203, or the layer conta1ns a mixture of 50 to 99.99 atom % of SiO. and of 50 to 0.01 atom % of MgO, or the layer contains a mixture of 80 to 99.99 atom % of SiO~ and of 20 to 0.01 atom % of La2O3, or the layer contains a mixture of 80 to 99.9g atom % of SiO~
and of 20 to 0.001 atom % of TiO2, or the layer contains a mi~ture of 80 to 99.99 atom % of SiO~ and of 20 to 0.01 atom ~ of ZrO2, or the layer contains 80 to 99.99 atom %
of SiO~ and of 30 to 0.01 atom % of B2O3, and x means a number from 1 to 2, are most particularly preferred.

Substrates in which the coating layer contains a mixture of 99 to 99.99 atom ~ of SiO~ and 1 to 0.01 atom % of Al2O3, or a mixture of 80 to 99.99 atom % of SiO~ and of 20 to 0.01 atom % of MgO, or a mixture of 95 to 99.99 atom % of SiO~ and of 5 to 0.01 atom % of La2O3, or a mixture of 95 to 99.99 atom % of SiO~ and of 5 to 0.01 atom % of TiO2, or a mixture of 9S to 99.99 atom % of SiO~
and of 5 to 0.01 atom % of ZrO2, or a mixture of 95 to 99.99 atom % of SiO~ and of 5 to 0.01 atom % of B2O3, and x means a number from 1 to 2, are particularly preferred.

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Furthermore, the present invention includes substrates containing thermoplastic polymers with a coating layer in the form of at least one surface layer and/or intermediate layer, for example in the form of a 5 to 500 nm, advantageously 10 to 200 nm, and preferably 40 to 150 nm thick layer of a mixture of at least two metal and/or semi-metal compounds applied by vaporising in vacuum.

Preferred substrates are those containing thermoplastic polymers with a coating layer in the form of at least one surface layer and/or intermediate layer as a layer of a mixture of two metal and/or semi-metal compounds from the series of oxides, carbides and nitrides of silicon, aluminium, magnasium, lanthanum, titanium, zirconium and boro~ applied by vaporising in vacuum.

The coated substrates of tha present invention and the materials produced therefrom have, for example a reduced or virtually complete gas permeability (for example air, oxygen, COz) and vapour permeability (for example water vapour).

The coated substrates of the present invention have a permeability or adsorption for electromagnetic waves of visible light which is unchanged compared to the uncoated layers, and reduce or prevent the passage of electromagnetic waves in the range of UV light.

Microwave radiation may also penetrate through a substrate coated according to the invention.

For example the oxygen permeation ~or a 0.1 ~m thick coating layer on a 12 ~m thick PET substrate is below 0.05 ccm/d.m2.bar at 23C.

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The layers of metal and/or semi-metal compounds adhere very strongly to the substrate and also withstand the conditions of sterilisation of, for example 30 minutes at 1~1C.

The substrates coated by the present invention are therefore preferably suitable for use as packaging materials or packing materials, or for producing packaging materials or packing materials, such as packaging films or laminates. In the substrates of the present invention, the coating layer is advantageously covered, for example by a film-like material, such as by a film or a film composite of thermoplastic plastics. The coating layer is thus protected against mechanical influences and the properties of the substrate may be expanded. In particular various packaging materials and packing materials are produced in this manner. For example packaging containers, such as bags, sachets, wrappers, pouches, covers, deep-drawn packings, meal dishes and the like may be produced from these packaging materials, or lid materials for deep-drawn packings or dish-like containers may be made. Containers of this type are suitable, for example for receiving foodstuffs for humans and animals or for luxury goods, in each case in solid, powder, liquid, gel-like or paste form. Further areas of application ~or the packaging material are packages for pharmacy and medicine, such as tablet packages, push-through packings and the like for receiving tablets, dragees, hard and soft gelatine capsules, products from the field of diagnostics, therapeutic agents and medicinal resources.

The present invention therefore also relates to the use of the substrates produced according to the present invention as packaging materials and packing materials or as starting materials or blanks for packaging materials and packing materials.

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ExamPles 1. A powder mixture of 90 wt.% of SiO2 and 10 wt.% of La203 is mixed with polyvinyl alcohol and a petroleum emulsion, the mixture is filtered and then moulded between a ram and die at 50 kg/cm2. The moulded body is then fired, wherein the organic constituents volatilise and the inorganic constituents are sin~ered such that an apparent density o~ about 50 % is reached.

A PET film 12 ~m thick is attached to the substrate support in a device containing a vacuum chamber, a substrate support, a vaporiser crucible and an electron beam gun, and the vaporiser crucible is filled with the sintered body of 90 wt.% of sio2 and lO wt.% of La203. The vacuum chamber is evacuated to a pressure of about 10-6 mbar.

The vaporiser crucible is exposed to the energy from the electron beam gun. The voltage is 10 kV, the beam current 0.1 mA and the coating capacity produced 8 nm/second.
After a treatment time of 10 seconds, a coating layer 80 nm thick is deposited on the substrate surface.

The coating layer on the substrate has a composition of 99 atom % of SiO2 and of l atom % of La203. The substrate is completely transparent, is not clouded and the oxygen permeability is less than 0.05 cm3/d.m2.bar at 23C.

The oxides in the coating layer are present as a mixture and not as superposed layers.

2. A plate-like moulded body having an apparent density of 50 ~ of the true density is produced from a pulverulent mixture o$ 18 wt.% of B203 and 82 wt.% of SiO2 (quartz powder). The moulded body is placed in a crucible and the crucible is placed in a vacuum chamber. The crucible contents are vaporised in vacuum by means of an electron beam. The length of the crucible supplied with the plate~like moulded bodies is 1,2S0 mm, wherein the crucible is arranged transversely to the direction o travel of a substrate film. A substrate film of 1~ ~m thick polyester with a width of 1,100 mm is guided over the crucible in the vacuum chamber. The electron beam heats a linear zone in the crucible transversely to the direction of travel of the film. The power of the electron beam is 70 kW, the conveying speed of the substrate film 200 m/minute.

Only a narrow strip is heated and partially melted by the electron beam due to the poor heat conduction of the plate-like moulded body and as a result of the low apparent density of the moulded body, and this leads to very good utilisation of energy. There is also no splash due to the low amount o~ partially melted material, The substrate film is taken from the vacuum chamber when t~e test is completed and a composite is produced with the substrate film. For this purpose the substrate film is lacquer-laminated with a cPP film 75 ~m thick. The oxygen barrier effect measured on this composite is 0.5 cm3 (m2 24h bar) at 23C.

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Claims (18)

1. Process for producing substrates containing thermoplastic plastics and a coating layer of inorganic compounds, by vaporising inorganic materials from vaporiser crucibles in vacuum at pressures of less than 10-1 mbar, wherein the vapour of the inorganic materials is produced in a chamber surrounding the vaporiser crucible and the substrate, and the vapour of the inorganic materials is precipitated on the substrate, characterised in that the inorganic materials are present in the vaporiser crucible at an apparent density which is 25 to 75 % of the true density of the inorganic materials.

2. Process according to claim 1, characterised in that the inorganic materials are present in the vaporiser crucible as filling, tapping, moulding, bulk, sinter or foam compositions.

3. Process according to claim 2, characterised in that the inorganic materials are present at an apparent density which is 25 to 75 % of the true density of the inorganic materials.

4. Process according to claim 1, characterised in that at least two inorganic materials are vaporised in vacuum at the same time with formation of a vapour-mixture, and the vapour mixture of the inorganic materials is precipitated directly onto the thermoplastic plastic of the substrate.

5. Process according to claim 1, characterised in that two inorganic materials are vaporised in vacuum at the same time with formation of a vapour mixture.

6. Process according to claim 1, characterised in that two different metals, semi-metals, metal and/or semi-metal compounds, as inorganic materials, are vaporised in vacuum at the same time with formation of a vapour mixture.

7. Process according to claim 1, characterised in that the metals and semi-metals silicon, aluminium, magnesium, lanthanum, titanium, boron and zirconium are used as inorganic materials and the oxides, carbides and nitrides of silicon, aluminium, magnesium, lanthanum, titanium, boron and zirconium are used as metal and semi-metal compounds.

8. Process according to claim 1, characterised in that two metal and/or semi-metal compounds are used as inorganic materials, wherein one compound is an oxide of silicon and at least one further compound is an oxide of aluminium, magnesium, lanthanum, titanium, boron or zirconium.

9. Process according to claim 8, characterised in that SiO2 and Al2O3 or SiO2 and MgO or SiO2 and La2O3 or SiO2 and TiO2 or SiO2 and ZrO2 or SiO2 and B2O3 are vapour-deposited at the same time.

10. Process according to claim 1, characterised in that the substrate is bombarded with N2, Ar or O2 ions during vaporisation of the inorganic materials.

11. Process according to claim 1, characterised in that the vaporisation and precipitation takes place in a reactive atmosphere.

12. Substrates produced by the process according to claim 1, containing thermoplastic plastics and a coating layer of inorganic compounds, characterised in that the coating layer has at least two metal and/or semi-metal compounds deposited directly on the thermoplastic plastic at the same time, containing a mixture of SiOx and Al2O3 or of SiOx and MgO or of SiOx and La2O3 or of SiOx and TiO2 or of SiOx and ZrOz or of SiOx and B2O3, wherein x means a number from 1 to 2 and SiOx is present in the mixture at 60 to 99.99 atom %.

13. Substrates according to claim 12, characterised in that the substrates contain a coating layer of a mixture of at least two metal and/or semi-metal compounds from the series of oxides, carbides and nitrides of silicon, aluminium, magnesium, lanthanum, titanium and zirconium.

14. Substrates according to claim 12, characterised in that the coating layer contains two metal and/or semi-metal compounds of the general formula Si1-zMzO2-.alpha.-.beta.N.alpha.C.beta.

wherein .alpha. and .beta. mean a number from O to 0.1, M has the meaning of Al, B, Mg, La, Ti or Zr and when M has the meaning Mg, z is a number from 0.001 to 0.5, or M has the meaning Ti, z is a number from 0.001 to 0.1, or M has the meaning B, z is a number from 0.001 to 0.4, or M has the meaning La, z is a number from 0.001 to 0.1, or M has the meaning Zr, z is a number from 0.001 to 0.1, or M has the meaning Al, z is a number from 0.001 to 0.1.

15. Substrates according to claim 12, characterised in that when M has the meaning of Mg, Ti, B, La, Zr or Al, z is a number from 0.001 to 0.1.

16. Substrates according to claim 12, characterised in that the substrates contain a coating layer of a mixture of two metal and/or semi-metal compounds and the coating layer preferably contains a mixture of 80 to 99.99 atom %
of SiOx and 20 to 0.01 atom % of Al2O3, or the layer contains a mixture of 50 to 99.99 atom % of SiOx and of 0.01 to 50 atom % of MgO, or the layer contains a mixture of 80 to 99.99 atom % of SiOx and of 20 to 0.01 atom % of La2O3, or the layer contains a mixture of 80 to 99.99 atom % of SiOx and of 20 to 0.001 atom % of TiO2, or the layer contains a mixture of 80 to 99.99 atom % of SiOx and of 20 to 0.01 atom % of ZrO2, or the layer contains 80 to 99.99 atom % of SiOx and of 30 to 0.01 atom % of B2O3, and x means a number from 1 to 2.

17. Substrates according to claim 12, characterised in that the coating layer contains a mixture of 99 to 99.99 atom % of SiOx and l to 0.01 atom % of Al2O3, or a mixture of 80 to 99.99 atom % of SiOx and of 20 to 0.01 atom % of MgO, or a mixture of 95 to 99.99 atom % of SiOx and of 5 to 0.01 atom % of La2O3, or a mixture of 95 to 99.99 atom % of SiOx and of 5 to 0.01 atom % of TiO2, or a mixture of 95 to 99.99 atom % of SiOx and of 5 to 0.01 atom % of ZrO2, or a mixture of 95 to 99.99 atom % of SiOx and of 5 to 0.01 atom % of B2O3, and x means a number from 1 to 2.

18. Use of the substrates produced according to claim 1 as packaging materials and packing materials or as starting materials or blanks for packaging materials and packing materials.