HK1119444B - Method for the production of a thin glassy coating on substrates in order to reduce gas permeation - Google Patents

Description

Method for producing thin glassy coatings on substrates to reduce gas permeation

Technical Field

The invention relates to a method for converting thin (0.05-5 μm) coatings containing perhydropolysilazane (also referred to as PHPS) or organopolysilazane as the main component into impermeable glassy layers which are distinguished by transparency and high gas barrier action. This conversion is achieved by irradiating the substrate with VUV light having a wavelength of < 230 nm and UV light having a wavelength of less than 300 nm for as short a treatment time as possible (0.1 to 10 minutes) at as low a temperature as possible which is tolerable for the particular substrate.

Background

It is known that (k.kamiya, t.tang, t.hashimoto, h.nasu, y.shimizu, res.rep.fac.eng.mie.univ., 26, 2001, 23-31), during the heat treatment of the PHPS layer, the bonds of alternating silicon and nitrogen atoms in the polymer backbone are broken hydrolytically, nitrogen and a part of the hydrogen bonded to the silicon escape as gaseous compounds, for example as ammonia, and the silanols formed are crosslinked as a result of condensation, thereby forming a 3D lattice consisting of ≡ Si-O- ] units, which have glassy properties:

SiH₂NH+2H₂O→Si(OH)₂+H₂+NH₃

the process can be monitored by ATR-IR spectroscopy with reference to the evanescent Si-NH-Si band and the Si-H band and the emerging Si-OH and Si-O-Si bands.

According to the prior art, this conversion can be initiated thermally (EP 0899091B 1, WO2004/039904A 1). In order to accelerate the process or to lower the reaction temperature, catalysts based on amines or/and metal carboxylates (Pt, Pd) or/and N-heterocyclic compounds are added (for example WO2004/039904A 1). At exposure times of 30 minutes up to 24 hours, the conversion process requires temperatures from room temperature to 400 ℃, with lower temperatures requiring longer exposure times and higher temperatures requiring shorter exposure times.

EP 0899091B 1 also describes the possibility of curing the layer without a catalyst in a 3% triethylamine water bath (duration 3 minutes).

JP 11166157 AA describes the use of a ceramic precursorA method of adding a light absorber to a bulk polysilazane layer, the light absorber dissociating by UV irradiation to remove amines. The method proposes the use of a wavelength of 150-400 nm, 50-200mW cm^-2And a treatment time of 0.02 to 10 minutes.

According to JP 11092666 AA, with UV light having a wavelength of more than 300 nm at 50mW cm, due to the addition of 0.01 to 30% by weight of a photoinitiator^-2And a treatment time of about 30 seconds to convert the polysilazane layer. In addition, an oxidizing metal catalyst (Pt, Pd, Ni..) may be added to increase the cure rate.

According to JP 10279362 AA, a layer of polysilflurane (average molecular weight 100-50000) is applied to a polyester film (5 nm-5 μm). Here, too, Pt or Pd catalysts and/or amine compounds are used to accelerate the oxidation reaction at low temperatures. The latter may be introduced as a component of the polysilazane coating, as an aqueous solution in an immersion bath, or as a vapor component in ambient air during the heat treatment. Furthermore, it is proposed to simultaneously irradiate with 150-400 nm UV light to activate the amine catalyst acting as a light absorber. The UV sources mentioned are high-pressure and low-pressure mercury vapor lamps, carbon and xenon arc lamps, excimer lamps (wavelength range 172 nm, 222 nm and 308 nm) and UV lasers. At a treatment time of 0.05-3 minutes, 20-300mW cm is required^-2UV power of (1). The subsequent heat treatment at high water vapor contents (50-100% relative humidity) for 10 to 60 minutes up to 150 ℃ is intended to further improve the layer properties, specifically in terms of gas barrier effect. The mentioned support materials for the ceramicized polysilazane layer also include films of plastic materials, for example PET, PI, PC, PS, PMMA, etc. Methods of applying the polysilazane layer include dip coating of a fabric, roll coating, bar coating, web coating, brush coating, spray coating, flow coating, and the like. The layer thickness obtained after conversion was about 0.4 μm.

For coating heat-sensitive plastic films, JP 10212114 AA describes the conversion of a polysilazane layer by means of IR irradiation to activate an optionally present amine or metal carboxylate, which is intended to accelerate the conversion of the layer. JP 10279362 AA also mentions that the simultaneous use of UV and IR radiation is beneficial for layer conversion, with far infrared (4-1000 microns) being preferred because the carrier film is thereby heated less intensely.

The conversion of polysilazanes by electron irradiation is described in JP 08143689 AA.

For the preparation of thin protective layers for magnetic tapes, EP 0745974B 1 describes an oxidation process using ozone, atomic oxygen and/or VUV photon radiation in the presence of oxygen and water vapor. This enables the treatment time at room temperature to be reduced to a few minutes. The mechanism mentioned therein is the oxidation of ozone or oxygen atoms. The VUV radiation optionally used is only used for generating these reactive species. By simultaneously supplying heat up to the tolerance limit of the substrate (PET 180 ℃), conversion times of a few seconds to a few minutes for a polysilazane layer of approximately 20 nm are achieved. In the tape coating, heat is supplied by being in close contact with a heated roller.

The UV radiation source mentioned is a lamp containing a radiation part with a wavelength below 200 nm: for example, low-pressure mercury vapor lamps having an emission portion of about 185 nm, and excimer lamps having an emission portion of about 172 nm. Another possible way mentioned to improve the layer properties is to incorporate fine (5-40 nm) inorganic particles (silica, alumina, zirconia, titania).

The coatings produced in the above-described manner, although having a layer thickness of only 5 to 20 nm, require relatively long curing times. Due to the low layer thickness, the defect formation is very high and the barrier action of the coating is unsatisfactory.

Disclosure of Invention

It is therefore an object of the present invention to provide a process for preparing transparent coatings which allows coating even temperature-sensitive substrates in a simple and economical manner to be achieved and the coatings obtained therefrom are distinguished by a high gas barrier action.

The invention achieves this object and relates to a process for preparing a vitreous transparent coating on a substrate: it is carried out by the following way: coating a substrate with a solution comprising a) a polysilazane of formula (1)

-(SiR’R”-NR)_n- (1)

Wherein R ', R', RIdentical or different and each independently of the others is hydrogen or optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl) alkyl, preferably a radical selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, phenyl, vinyl or 3- (triethoxysilyl) propyl, 3- (trimethoxysilyl) propyl, where n is an integer and the size of n is such that the polysilazane has a number average molecular weight of from 150 to 150,000 g/mol, and b) a catalyst in an organic solvent, followed by removal of the solvent by evaporation to leave a polysilazane layer having a layer thickness of from 0.05 to 3.0 μm on the substrate and irradiation with VUV radiation having a wavelength component of < 230 nm and UV radiation having a wavelength component of from 230 to 300 nm, in an atmosphere containing water vapor, in the presence of oxygen, active oxygen and optionally nitrogen, the polysilazane layer is irradiated.

The catalyst used is preferably a basic catalyst, in particular N, N-diethylethanolamine, N-dimethylethanolamine, triethanolamine, triethylamine, 3-morpholinopropylamine or an N-heterocyclic compound. The catalyst concentration is generally from 0.1 to 10 mol%, preferably from 0.5 to 7 mol%, based on the polysilazane.

In a preferred embodiment, a solution comprising at least one perhydropolysilazane of formula 2 is used.

In a further preferred embodiment, the coating according to the invention comprises at least one polysilazane of the formula (3)

-(SiR’R”-NR’”)_n-(SiR^＊R^＊＊-N^＊＊＊)_p- (3)

Wherein R ', R', R^*、R^**And R^***Independently of one another, hydrogen or optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl) alkyl, where n and p are integers and the size of n is such that the polysilazane has a number average molecular weight of from 150 to 150000 g/mol.

Particularly preferred are the compounds wherein

-R ', R' "and R^***Is hydrogen, and R', R^*And R^**Is methyl;

-R ', R' "and R^***Is hydrogen, and R', R^*Is methyl and R^**Is a vinyl group;

-R’、R’”、R^*and R^***Is hydrogen, and R' and R^**Is methyl.

Preference is likewise given to solutions comprising at least one polysilazane of the formula (4)

-(SiR’R”-NR’”)_n-(SiR^＊R^＊＊-NR^＊＊＊)_p-(SiR¹，R²-NR³)_q- (4)

Wherein R ', R', R^*、R^**、R^***、R¹、R²And R³Independently of one another, hydrogen or optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl) alkyl, where n, p and q are integers and the size of n is such that the polysilazane has a number average molecular weight of from 150 to 150000 g/mol.

Particularly preferred compounds are R ', R' "and R^***Is hydrogen and R', R^*、R^**And R²Is methyl, R³Is (triethoxysilyl) propyl and R¹Those which are alkyl or hydrogen.

Generally, the polysilazane content in the solution is from 1 to 80% by weight of polysilazane, preferably from 5 to 50% by weight, more preferably from 10 to 40% by weight.

Suitable solvents are in particular organic, preferably aprotic solvents which are free of water and any reactive groups (for example hydroxyl or amine groups) and which are inert towards polysilazanes. They are, for example, aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, esters, such as ethyl acetate or butyl acetate, ketones, such as acetone or methyl ethyl ketone, ethers, such as tetrahydrofuran or dibutyl ether, and mono-and polyalkylene glycol dialkyl ethers (Glymes) or mixtures of these solvents. Preferably, the solvent used is an aprotic solvent which is inert with respect to the polysilazane.

Additional ingredients of the polysilazane solution may be other binders such as those commonly used to prepare coatings. They may be, for example, cellulose ethers and esters, such as ethylcellulose, nitrocellulose, cellulose acetate or cellulose acetobutyrate, natural resins, such as rubber or rosin resins, or synthetic resins, such as addition-polymerization resins or condensation resins, for example aminoplasts, in particular urea-and melamine-formaldehyde resins, alkyd resins, acrylic resins, polyesters or modified polyesters, epoxides, polyisocyanates or blocked polyisocyanates, or polysiloxanes.

Another component of the polysilazane formulation may be, for example, an additive which influences the viscosity, substrate wetting, film formation, lubrication or air drying properties of the formulation, or an inorganic nanoparticle, for example SiO₂、TiO₂、ZnO、ZrO₂Or Al₂O₃。

The method according to the invention makes it possible to produce impermeable vitreous layers which are distinguished by a high gas barrier owing to their freedom from cracks and pores.

The resulting coating has a layer thickness of 100 nm to 2 μm.

The substrate used according to the invention is a plastic film having a thickness of 10 to 100 micrometers, in particular a temperature-sensitive plastic film having a thickness of 10 to 100 micrometers or a plastic substrate (e.g. a three-dimensional substrate such as a PET bottle), in particular a film or substrate made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Polyimide (PI), polypropylene (PP), Polyethylene (PE), to name a few. In a further preferred embodiment, substrates such as metal foils, for example aluminum and titanium foils, can also be coated.

The excellent barrier action against gases, in particular against water vapour, oxygen and carbon dioxide, makes the coating according to the invention particularly useful as a barrier layer for packaging materials and as a protective layer against corrosive gases, for example for coating containers or films for the food industry. The method according to the invention is used to successfully convert the amorphous silazane layer applied in the first step into a vitreous silica network at a temperature of less than 100 ℃ in 0.1 to 10 minutes. This enables roll-to-roll coating on films at transport speeds of more than 1 m/min. For this reason, the processes known hitherto in the prior art require a plurality of process steps or the conversion has to be carried out at relatively high temperatures and with a relatively large expenditure of time.

Due to the oxidative conversion of the polysilazane skeleton directly into three-dimensional SiO by VUV photons_xThe network, using a single step in a minimum of time, successfully achieves this conversion. The mechanism of this transformation process can be explained as: strong excitation of-SiH by absorption in the region of the penetration depth of VUV photons₂-NH units, so that the Si-N bonds are broken and the conversion of the layer is completed in the presence of oxygen and water vapor.

Suitable radiation sources according to the invention are excimer radiators having an emission maximum of about 172 nm, low-pressure mercury vapor lamps having an emission line of about 185 nm, and medium-pressure and high-pressure mercury vapor lamps having a wavelength portion below 230 nm, and excimer lamps having an emission maximum of about 222 nm.

In using radiation sources having a radiation portion with a wavelength below 180 nm, e.g. Xe with an emission maximum of about 172 nm₂ ^*In the case of excimer radiators, ozone and oxygen or hydroxyl radicals, which promote the oxidation of the polysilazane layer, are formed very efficiently by photolysis in the presence of oxygen and/or water vapor due to the high absorption coefficient of these gases in this wavelength range. However, both mechanisms, the cleavage of the Si — N bond and the action of ozone, oxygen radicals and hydroxyl radicals, can only act when VUV radiation also reaches the surface of the polysilazane layer.

Therefore, in order to reach the layer surface with as high a dose of VUV radiation as possible, for this wavelength range, the oxygen concentration and the water vapor concentration in the radiation path length must be correspondingly reduced in a controlled manner by optionally purging the VUV treatment channel with nitrogen gas, in which oxygen and water vapor can be added in a controlled manner.

The oxygen concentration is preferably 500-210000ppm here.

The concentration of water vapor during the conversion has proven advantageous and can promote the reaction, so that a concentration of 1000 to 4000ppm of water vapor is preferred.

In a preferred embodiment according to the invention, the irradiation of the layer is carried out in the presence of ozone. In this way, the active oxygen required for the implementation of the method can be formed in a simple manner by decomposition of ozone during irradiation.

From HgLP lamps (185 nm) or KrCl^*The effect of the excimer lamp (222 nm) without UV light in the wavelength region below 180 nm is limited to the direct photodecomposition of the Si-N bond, i.e. no formation of oxygen or hydroxyl radicals. In this case, there is no need to limit the oxygen and water vapor concentrations due to negligible absorption. Another advantage over shorter wavelength light is a higher penetration depth into the polysilazane layer.

According to the invention, the irradiation with VUV radiation and UV radiation can be carried out simultaneously, successively or alternately, both with VUV radiation below 200 nm, in particular below 180 nm, or with VUV radiation having a wavelength component of 180 to 200 nm and with UV radiation having a wavelength component of 230 to 300 nm, in particular with UV radiation of 240 to 280 nm. In this case, a synergistic effect can be produced by decomposing ozone formed by radiation of a wavelength portion lower than 200 nm by radiation of a wavelength portion from 230 to 300 nm to form oxygen radicals (reactive oxygen).

O₂+hv(＜180nm)→O(³P)+O(¹D)

O(³P)+O₂→O₃

O₃+hv(＜300nm)→O₂(¹Δg)+O(¹D)

When this process occurs on the layer surface or within the layer itself, the layer conversion process can be accelerated. For this combination, a suitable radiation source is Xe having a wavelength fraction of about 172 nm₂ ^*An excimer radiator and a low or medium pressure mercury lamp having a wavelength portion of about 254 nm or 230 and 280 nm.

According to the invention, SiO is accelerated by simultaneous heating of the layers_xThe formation of a glassy layer in the form of a lattice and the quality of the layer in terms of its barrier properties is improved.

The heat input can be effected by the UV lamps used, or by infrared radiators through the coating and the substrate, or by heating the recorder through the gas space. The upper temperature limit is determined by the thermal stability of the substrate used. For PET film, it is about 180 ℃.

In a preferred embodiment of the invention, the substrate is heated to a temperature of from 50 to 200 ℃ during the oxidative conversion by means of an infrared radiator (depending on the temperature sensitivity of the substrate to be coated) and is simultaneously exposed to radiation, i.e. the substrate is heated to a temperature of from 50 to 200 ℃ during the oxidative conversion, depending on the thermal stability of the substrate, on irradiation with the infrared radiator. In a further preferred embodiment, during the oxidative conversion, the gas temperature is heated to a temperature of from 50 to 200 ℃ upon irradiation in the irradiation chamber, depending on the thermal stability of the substrate, i.e. the gas temperature in the irradiation chamber during the conversion is increased to a temperature of from 50 to 200 ℃ and thereby a simultaneous heating of the coating on the substrate is achieved, which causes an accelerated conversion of the polysilazane layer.

The gas barrier effect of the layer can be determined by means of permeation measurements with respect to the residual content of Si-H and Si-NH-Si bonds and the Si-OH and Si-O-Si bonds formed, by means of ATR-IR measurements. The morphology of the layer is typically determined by REM measurements. Measurement of nitrogen and SiO perpendicular to the layer surface by SIMS in the simplest manner_xThe concentration gradient of (1).

The method of the invention enables the coating, drying and oxidative conversion by irradiation of the polysilazane layer on the plastic film to be carried out in one process step, i.e. for example in the "roll-to-roll" coating of the film. The coatings obtained according to the invention are distinguished by a high barrier action against gases, such as oxygen, carbon dioxide, air or against water vapor.

The barrier effect can be further enhanced by multiple successive executions of the process of the invention when desired, but this is generally not necessary.

Detailed Description

Examples

Substrate:

polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Polyimide (PI), Polyethylene (PE), polypropylene (PP).

Polysilazane solution:

perhydropolysilazane solution in xylene (NP110, NN110 from Clariant GmbH) or in dibutyl ether (NL120, NN120 from Clariant GmbH).

A basic catalyst (e.g., N-diethylethanolamine, triethanolamine, triethylamine, 3-morpholinopropylamine, N-heterocyclic carbene) is added.

(1 to 5% catalyst based on polysilazane solids).

The coating method comprises the following steps:

dipping, reel-to-reel, spin coating. Then dried at 100 ℃ for 5 minutes.

Oxidative conversion:

by means of Xe₂ ^*Excimer radiator, emission of about 172 nm, VUV power 30mW cm^-2With the aid of a low-pressure mercury vapor lamp (HgLP lamp), a VUV power of 10mW cm at an emission line of 185 nm_-2Conversion of perhydropolysilazanes (PHPS) to SiO by VUV radiation_xA network. Formed SiO_xThe film has a layer thickness of 200 to 500 nm (REM, ellipsometry). Determination of the barrier value:

OTR (oxygen transmission rate) at 23 ℃ and 0% relative humidity or 85% relative humidity

WVTR (Water vapor Transmission Rate) at 23 ℃ or 40 ℃ and 90% relative humidity

For about 200 nm SiO_xLayer, OTR 0.5-0.8cm³ m^-2Sky^-1Bar^-1

For about 300 nm SiO_xLayer of 0.1-0.4cm OTR³ m^-2Sky^-1Bar^-1

And WVTR is 0.5-1.0g m^-2Sky^-1Bar^-1。

For two SiO_xLayer (total of about 400 nm))，

OTR＝0.05-0.15cm³ m^-2Sky^-1Bar^-1And WVTR is 0.2-0.4g m^-2Sky^-1Bar^-1。

For three SiO_xA layer (approximately 500 nanometers in total),

OTR＜0.03cm³ m^-2sky^-1Bar^-1And WVTR < 0.03g m^-2Sky^-1Bar^-1。

Example 1:

36 μm PET films were coated by dipping with 3% solutions of perhydropolysilazane in xylene (NP110) or dibutyl ether (NL120), dried at 100 ℃ for 5 minutes, treated with Xe₂ ^*Excimer radiation 30mW cm^-2(1 minute, 2500ppm O₂10% relative humidity) and a layer thickness of about 300 nm.

OTR (23 ℃, 0% relative humidity) ═ 0.2 or 0.3cm³ m^-2Sky^-1Bar^-1

Uncoated comparative film: OTR of 36 micron PET film is 45-50cm³ m^-2Sky^-1Bar^-1

Barrier Improvement Factor (BIF) ═ OTR (uncoated)/OTR (coated)

BIF (NP110) 225 and BIF (NL120) 150-

Example 2:

a36 μm PET film was coated with a 3% solution of perhydropolysilazane in xylene (NP110) or dibutyl ether (NL120) with the addition of an amino catalyst (5% triethanolamine based on PHPS), by dip coating, dried at 100 ℃ for 5 minutes, with Xe₂ ^*Excimer radiation 30mW cm^-2(1 minute, 2500ppm O₂10% relative humidity) and a layer thickness of about 300 nm.

OTR (23 ℃, 0% relative humidity) ═ 0.14 or 0.24cm³ m^-2Sky^-1Bar^-1

Uncoated comparative film: OTR is 45-50cm³ m^-2Sky^-1Bar^-1

BIF (NP110+ Kat) 321-

WVTR (23 ℃, 90% relative humidity) ═ 1.0g m^-2Sky^-1Bar^-1

Example 3:

a36 μm PET film was coated with a 3% solution of perhydropolysilazane in xylene (NN110) or dibutyl ether (NN120) with the addition of an amino catalyst (5% N, N-diethylethanolamine based on PHPS), by dip coating, dried at 100 ℃ for 5 minutes, with Xe₂ ^*Excimer radiation 30mW cm^-2(1 minute, 2500ppm O₂10% relative humidity) and a layer thickness of about 300 nm.

OTR (23 ℃, 0% relative humidity) ═ 0.4 or 0.2cm³ m^-2Sky^-1Bar^-1

Uncoated comparative film: OTR is 45-50cm³ m^-2Sky^-1Bar^-1

BIF (NN110+ Kat) 113-

Example 4:

a36 μm PET film was coated with a 3% solution of perhydropolysilazane in xylene (NP110) to which 5% of an amino catalyst (N, N-diethylethanolamine, triethylamine, triethanolamine) based on PHPS was added, by dip coating, dried at 100 ℃ for 5 minutes, and impregnated with Xe₂ ^*Excimer radiation 30mW cm^-2(1 minute, 2500ppm O₂10% relative humidity) oxidative conversion or heat transfer at 65 deg.CTaking 30 minutes, the layer thickness was about 300 nm.

Example 5:

a36 μm PET film was coated with a 3% solution of perhydropolysilazane in xylene (NP110) to which 5% of an amino catalyst (N, N-diethylethanolamine) based on PHPS was added, by dip coating, dried at 100 ℃ for 5 minutes, with Xe₂ ^*Excimer radiation 30mW cm^-2(1 minute, 2500ppm O₂10% relative humidity) and then coated again in the same manner, dried and oxidatively converted: a total of two SiO_xLayer thickness 400-500 nm.

OTR (23 ℃, 0% relative humidity) ═ 0.05-0.1cm³ m^-2Sky^-1Bar^-1

WVTR (23 ℃, 90% relative humidity) ═ 0.2g m^-2Sky^-1Bar^-1

Example 6:

a36 μm PET film was coated with a 3% solution of perhydropolysilazane in xylene (NP110) to which 5% of an amino catalyst (N, N-diethylethanolamine) based on PHPS was added, by dip coating, dried at 100 ℃ for 5 minutes under Xe₂ ^*Excimer radiation 30mW cm^-2(1 minute, 2500ppm O₂10% relative humidity) and then coated twice more in the same manner, dried and oxidatively transformed: a total of three SiO_xLayer thickness 500-.

OTR (23 ℃, 0% relative humidity) ═ 0.01-0.03cm³ m^-2Sky^-1Bar^-1

WVTR (23 ℃, 90% relative humidity) ═ 0.03g m^-2Sky^-1Bar^-1

Example 7:

a36 μm PET film was coated with a 3% solution of perhydropolysilazane in xylene (NP110) to which 5% of an amino catalyst (N, N-diethylethanolamine) based on PHPS was added, by dip coating, dried at 100 ℃ for 5 minutes, oxidatively converted with HgLP radiation, VUV power 10mW cm^-2(10 min, 2500ppm O₂10% relative humidity), the layer thickness is about 300 nm.

OTR (23 ℃, 0% relative humidity) ═ 0.2cm³ m^-2Sky^-1Bar^-1

Example 8:

a23 micron PET film was coated with a 3% solution of perhydropolysilazane in xylene (NP110) or dibutyl ether (NL120) with the addition of 5% of an amino catalyst (N, N-diethylethanolamine) based on PHPS, roll-to-roll coated with Xe₂ ^*Excimer radiation (double lamps, 120 cm tilt) 33mW cm^-2(3 m/min, 2500ppm O₂6% relative humidity) and a layer thickness of about 400 nm.

OTR (23 ℃, 0% relative humidity) ═ 0.65 or 0.35cm³ m^-2Sky^-1Bar^-1

Example 9:

the PET film is coated with a solution of polysilazane in xylene or dibutyl ether, with the addition of an amino catalyst, roll-to-roll coated with Xe₂ ^*Excimer radiation 30mW cm^-2(O₂，H₂O) oxidative + thermal conversion, with a layer thickness of about 300 nm.

Example 10:

PET bottles were coated with a solution of polysilazane in xylene or dibutyl ether to which was added an amino catalyst, by dip coating at 65 deg.CDrying for 5 min with Xe₂ ^*Excimer radiation 30mW cm^-2(5 min, 2500ppm O₂10% relative humidity) and a layer thickness of about 400 nm.

Barrier Improvement Factor (BIF) for O₂For CO 10 ═ 10₂＝3。

Example 11:

a23 micron PET film was coated with a 3% solution of perhydropolysilazane in dibutyl ether (NL120) with 5% addition of an amino catalyst (N, N-diethylethanolamine) based on PHPS, roll-to-roll, with Xe₂ ^*Excimer radiation 250mJ cm^-2And Hg-LP radiation 250mJ cm^-2(1 m/min, 2500ppm O²7% relative humidity) and a layer thickness of about 400 nm. Gas feed OTR (23 ℃, 0% relative humidity) 1.3cm opposite to the direction of travel from the excimer radiator to the Hg-LP radiator³ m^-2Sky^-1Bar^-1

Example 12:

a23 micron PET film was coated with a 3% solution of perhydropolysilazane in dibutyl ether (NL120) with 5% addition of an amino catalyst (N, N-diethylethanolamine) based on PHPS, roll-to-roll, with Xe₂ ^*Excimer radiation 250mJ cm^-2And Hg-LP irradiation 250mJcm^-2(1 m/min, 10000ppm O₂7% relative humidity) and a layer thickness of about 400 nm. Gas feed OTR (23 ℃, 0% relative humidity) 1.0cm opposite to the direction of travel from the excimer radiator to the Hg-LP radiator³ m^-2Sky^-1Bar^-1

Example 13:

a23 micron PET film was coated with a 3% solution of perhydropolysilazane in dibutyl ether (NL120) with 5% addition of an amino catalyst (N, N-diethylethanolamine) based on PHPS, roll-to-roll, with Xe₂ ^*Excimer radiation 100mJ cm^-2And Hg-LP irradiation 250mJcm^-2(1 m/min, 2500ppm O₂250ppm ozone, 7% relative humidity) and a layer thickness of about 400 nm. Gas feed OTR (23 ℃, 0% relative humidity) of 0.75cm opposite to the direction of travel from the excimer radiator to the Hg-LP radiator³ m^-2Sky^-1Bar^-1

Example 14:

a23 micron PET film was coated with a 3% solution of perhydropolysilazane in dibutyl ether (NL120) with 5% addition of an amino catalyst (N, N-diethylethanolamine) based on PHPS, roll-to-roll, with Xe₂ ^*Excimer radiation 500mJ cm^-2And Hg-LP irradiation 250mJcm^-2(1 m/min, 2500ppm O₂100ppm ozone, 7% relative humidity) and a layer thickness of about 400 nm. Gas feed OTR (23 ℃, 0% relative humidity) opposite to the direction of operation from the excimer radiator to the Hg-LP radiator

Table 1: range (I/I) of radiation at wavelengths 162, 172 and 182 nanometers in various concentrations of nitrogen-oxygen mixtures₀＝1/e＝36.8％)

Claims (22)

1. A method for producing a glassy transparent coating on a substrate, which is carried out by: coating a substrate with a solution comprising

a) Polysilazanes of formula (1)

-(SiR’R”-NR’”)_n- (1)

Wherein R ', R ", R'" are identical or different and are each independently of the other hydrogen or optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl) alkyl, wherein n is an integer and the size of n is such that the polysilazane has a number average molecular weight of from 150 to 150,000 g/mol, and

b) a catalyst in an organic solvent, wherein the catalyst is selected from the group consisting of,

the solvent is subsequently removed by evaporation, thereby leaving a polysilazane layer having a layer thickness of 0.05 to 3.0 μm on the substrate, and the polysilazane layer is irradiated with VUV radiation having a wavelength component of < 230 nm and UV radiation having a wavelength component of 230 to 300 nm in an atmosphere containing water vapor in the presence of oxygen, active oxygen and optionally nitrogen, wherein the irradiation with VUV and UV radiation is carried out simultaneously, successively or alternately.

2. The process of claim 1, wherein the catalyst used is a basic catalyst.

3. The process of claim 2, wherein the basic catalyst is N, N-diethylethanolamine, N-dimethylethanolamine, triethanolamine, triethylamine, 3-morpholinopropylamine, or an N-heterocyclic compound.

4. The process as claimed in any of claims 1 to 3, wherein the solvent used is an aprotic solvent which is inert with respect to the polysilazane.

5. The method of at least one of the preceding claims, wherein the solution contains 1 to 80 wt.% polysilazane.

6. The method of claim 5, wherein the solution contains 5 to 50 weight percent polysilazane.

7. The method of claim 5, wherein the solution contains 10 to 40 weight percent polysilazane.

8. Method according to at least one of the preceding claims, wherein VUV radiation with a wavelength component < 180 nm is used.

9. The process of at least one of claims 1 to 7, wherein VUV radiation having a wavelength component of from 180 to 230 nm is used.

10. The process of at least one of the preceding claims, wherein the oxygen concentration is 500-210000 ppm.

11. The process of at least one of the preceding claims wherein the water vapor concentration is from 1000 to 4000 ppm.

12. Method according to at least one of the preceding claims, wherein ozone is additionally supplied during the irradiation.

13. The process according to at least one of the preceding claims, wherein R ', R ", R'" in formula (1) are independently of each other a group selected from hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, phenyl, vinyl or 3- (triethoxysilyl) propyl, 3- (trimethoxysilyl) propyl.

14. The process of at least one of the preceding claims, wherein the solution comprises at least one perhydropolysilazane of the formula (2)

15. The process of at least one of the preceding claims, wherein the solution comprises at least one polysilazane of formula (3)

-(SiR’R”-NR’”)_n-(SiR^＊R^＊＊-NR^＊＊＊)_p- (3)

Wherein R ', R', R^*、^**And R^***Independently of one another, hydrogen or optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl) alkyl, where n and p are integers and the size of n is such that the polysilazane has a number average molecular weight of from 150 to 150,000 g/mol.

16. The process of at least one of the preceding claims, wherein in formula (3)

-R ', R' "and R^***Is hydrogen, and R', R^*And R^**Is methyl;

-R ', R' "and R^***Is hydrogen, and R', R^*Is methyl and R^**Is a vinyl group; or

-R’、R’”、R^*And R^***Is hydrogen, and R' and R^**Is methyl.

17. The process of at least one of the preceding claims, wherein the solution comprises at least one polysilazane of formula (4)

-(SiR’R”-NR’”)_n-(SiR^＊R^＊＊-NR^＊＊＊)_p-(SiR¹，R²-NR³)_q- (4)

Wherein R ', R', R^*、R^**、R^***、R¹、R²And R³Independently of one another, hydrogen or optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl) alkyl, where n, p and q are integers and the size of n is such that the polysilazane has a number average molecular weight of from 150 to 150,000 g/mol.

18. A method according to at least one of the preceding claims, wherein the substrate is heated to a temperature of from 50 to 200 ℃ during the oxidative conversion, upon irradiation with an infrared radiator, depending on the thermal stability of the substrate.

19. Method according to at least one of the preceding claims, wherein during the oxidative conversion, the gas temperature is heated to a temperature of 50 to 200 ℃ upon irradiation in the irradiation chamber, depending on the thermal stability of the substrate.

20. The process of at least one of the preceding claims wherein the substrate is a plastic film having a thickness of 10 to 100 microns.

21. The method of at least one of the preceding claims, wherein the substrate is a polyethylene terephthalate, polyethylene naphthalate, polyimide, polypropylene or polyethylene film.

22. Method according to at least one of the preceding claims, wherein the coating of the polysilazane layer on the plastic film, the drying and the oxidative conversion by irradiation are carried out in one process step in a roll-to-roll manner.