WO2023198746A1

WO2023198746A1 - Flexible multi-layered polysiloxane hard coating

Info

Publication number: WO2023198746A1
Application number: PCT/EP2023/059508
Authority: WO
Inventors: Tiina ALAHAIVALA; Rakib KABIR; Ari KÄRKKÄINEN; Sacha Legrand; Tiina LEPPÄJÄRVI; Kaisa MALO; Matti Pesonen; Mia VIRKKUNEN
Original assignee: Optitune Oy
Priority date: 2022-04-14
Filing date: 2023-04-12
Publication date: 2023-10-19
Also published as: TW202402542A

Abstract

The present invention relates to a layered structure comprising a flexible or bendable substrate layer (A), a first polysiloxane based coating layer (B) and a second polysiloxane based coating layer (C), a method for preparing said layered structure and the use of said layered structure for flexible electronics applications.

Description

Flexible multi-layered polysiloxane hard coating

Technical background

Transparent plastics have been widely used as a core material in optical and transparent display industries. In particular, transparent plastics such as PET (polyethylene terephthalate), PI (polyimide), PC (polycarbonate) or PMMA (polymethyl methacrylate) have been applied in flexible electronics applications, including displays, optical lens, transparent boards, and automotive industries as a lightweight alternative to glass owing to the properties of high light transmittance and suitable refractive index. However, these plastics have the disadvantage of low abrasion resistance, because they have lower surface hardness than glass.

For increasing abrasion resistance and photopatternability hard coating films have been suggested, which are flexible and bendable. Suitable flexible hard coatings are for instance polysiloxane based flexible hard coatings as e.g. disclosed in WO 2019/193258.

Hard coatings have the drawback of reducing the visibility of e.g. the display due to an increased light reflection. In order to reduce light reflections antireflective coatings have been proposed as additional layer on hard coating layers in multilayer approaches.

For instance WO 2006/082701 Al discloses a two-layer coating on a transparent plastic film substrate with a first hard coating layer from a material which contains a (meth)acrylate group containing curable compound and a (meth)acrylate group- containing reactive silicone and a second antireflection (low refractive) coating layer from a material which contains a siloxane component containing compound.

Other two layer approaches of a hard coating layer and a low refractive layer are suggested e.g. in US 11,046,827 B2 and KR 2004-0076422A.

Even three-layer coatings of a hard coating layer, a high refractive layer and a low refractive layer have been suggested e.g. in JP 2001-293818A. Such multilayer approaches have the drawback of reduced scratch resistance and a mismatch of refractive indices, which results in a heavy rainbow pattern as discussed e.g. in as discussed in CN 206270519 U. On reason for the poor scratch resistance could be that the hard coating layer for improving scratch resistance is usually the inner layer in direct contact with the plastic substrate and the adhesion to the low refractive outer layer is rather weak.

When applying the low refractive layer as inner layer and the hard coating layer as outer layer as discussed in TW 2009-16818 A the coating shows good scratch resistance and lower rainbow pattern but does not address the problem of high reflectance.

Thus, there is a need in the art for flexible coatings on transparent plastic substrates, which are flexible and show an improved balance of properties in regard of mechanical properties such as scratch resistance and optical properties such as a low refractive index for reducing light reflection.

In the present invention a multilayer coating is suggested which shows such an improved balance of properties. Said multilayer coating comprises two polysiloxane based coating layers, whereas the inner layer is a polysiloxane based flexible hard coating layer and the second layer is an antireflective layer.

Summary of the invention

The present invention relates to a layered structure comprising

(A) a substrate layer; and

(B) a first coating layer coated on at least one surface of the substrate layer (A), and

(C) a second coating layer coated on at least one surface of the first coating layer (B) so that the second coating layer (C) is in adherent contact with at least one surface of the first coating layer (B) wherein the first coating layer (B) comprises a first siloxane polymer (B-l); the second coating layer (C) comprises one or more second siloxane polymer(s) (C- 1); and the substrate layer (A) is flexible, bendable or both.

Further, the present invention relates to a method for producing a layered structure as described above or below comprising the following steps:

• Providing a first composition comprising at least two different silane monomers, wherein at least one of the silane monomers includes an active group capable of achieving cross-linking to adjacent siloxane polymer;

• Subjecting the first composition to at least partial hydrolysis of the monomers to form a composition comprising a first siloxane polymer (B-l);

• Providing a second composition comprising at least one silane monomer;

• Subjecting the second composition to at least partial hydrolysis of the monomers to form a composition comprising one or more second siloxane polymer(s) (C- i);

• Providing a substrate which is flexible or bendable or both;

• Depositing the first composition onto at least one surface of the substrate to form a first coating layer (B);

• Cross-linking the siloxane polymer chains of the first coating layer (B) as to obtain a first coating layer (B) comprising a cross-linked siloxane polymer in adherent contact with the at least one surface of the substrate;

• Depositing the second composition onto the first coating layer (B) to form a second coating layer (C) in adherent contact with the first coating layer (B);

• Cross-linking the siloxane polymer chains of the second coating layer (C) as to obtain a second coating layer (C) comprising one or more cross-linked siloxane polymer(s) in adherent contact with the first coating layer (B). The inventive multi-layer coating shows good interlayer adhesion resulting in an improved balance of properties in regard of mechanical properties, especially scratch resistance, and optical properties, especially a low refractive index.

In one specific embodiment a further third coating layer is applied onto the second coating layer, which further improves the mechanical properties of the multi-layer coating.

In said specific embodiment the invention relates to a layered structure comprising

(A) a substrate layer; and

(B) a first coating layer coated on at least one surface of the substrate layer (A),

(C) a second coating layer coated on at least one surface of the first coating layer

(B) so that the second coating layer (C) is in adherent contact with at least one surface of the first coating layer (B), and

(D) a third coating layer (D) coated on at least one surface of the second coating layer (C) so that the third coating layer (D) is in adherent contact with at least one surface of the second coating layer (C), wherein the first coating layer (B) comprises a first siloxane polymer (B-l); the second coating layer (C) comprises one or more second siloxane polymer(s) (C- 1); and the substrate layer (A) is flexible, bendable or both.

Further, in said specific embodiment the invention relates to a method for producing a layered structure as described above or below comprising the following steps:

• Subjecting the first composition to at least partial hydrolysis of the monomers to form a composition comprising a first siloxane polymer (B-l); • Providing a second composition comprising at least one silane monomer;

• Providing a third composition comprising at least one silane monomer and at least one monomer comprising a fluorinated carbon group;

• Subjecting the third composition to at least partial hydrolysis of the monomers to form a composition comprising a siloxane polymer, which comprises side chains comprising one or more fluorinated carbon groups;

• Providing a substrate which is flexible or bendable or both;

• Cross-linking the siloxane polymer chains of the second coating layer (C) as to obtain a second coating layer (C) comprising one or more cross-linked siloxane polymer(s) in adherent contact with the first coating layer (B);

• Depositing the third composition onto the second coating layer (C) to form a third coating layer (D) in adherent contact with the second coating layer (C);

• Cross-linking the siloxane polymer chains of the third coating layer (D) as to obtain a third coating layer (D) comprising one or more cross-linked siloxane polymer(s) in adherent contact with the second coating layer (C).

Finally, the present invention relates to the use of the layered structure as described above or below for flexible electronics applications, including displays, optical lens, transparent boards, and automotive industries especially as a lightweight alternative to glass.

Various exemplifying and non-limiting embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in connection with the accompanying drawings.

The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually free combinable unless otherwise explicitly stated.

Description of the invention

The present technology provides for layered structures wherein a substrate layer (A) is provided with at least two layers comprising siloxane polymers. The layered structure is “bendable” in the sense that it is capable of being bent about a mandrel, having a radius of curvature, without breaking.

The properties of bendability can be tested using a test involving infolding or outfolding of the layered structure about a mandrel as described in WO 2019/193258.

Substrate layer (A)

The substrate layer (A) can be any kind of substrates such as glass, quartz, silicon, silicon nitride, polymers, metals and plastics or mixtures thereof. Furthermore, the substrate layer (A) can also include number of different surfaces such as different oxides, doped oxides, semimetals and the like or mixture thereof.

Suitable polymers are e.g. thermoplastic polymers, such as polyolefins, polyesters, polyamides, polyimides, polycarbonates, acrylic polymers, such as poly(methylmethacrylate), and Custom Design polymers. Especially preferred polymers are polymethylmethacrylate (PMMA), polyethyleneterephtalate (PET) and colorless polyimide (CPI).

The substrate layer (A) can be the outmost layer of a device or an internal layer of a single stack. The substrate layer (A) can be coated on one or both sides.

The substrate layer (A) preferably has a thickness of 10 to 500 pm, more preferably 20 to 400 pm.

The substrate layer (A) is flexible, bendable or both, such that it is capable of being bent about a mandrel having a first minimum radius of curvature without breaking. A layered structure of the present kind is in particular capable of being bent about a mandrel having a second minimum radius of curvature without breaking, said first minimum radius being smaller or equal to the second minimum radius of curvature.

The at least one surface of the substrate layer (A) can be modified before depositing the first composition onto at least one surface of the substrate to form a first coating layer (B).

The at least one surface of the substrate layer (A) can be modified physically or chemically.

Suitable physical modifications are plasma treatment or corona treatment or similar treatments.

Suitable chemical modifications could be a chemical cleaning process for cleaning the at least one surface of the substrate layer (A).

By means of physical or chemical modification the at least one surface is preferably activated to promote adhesion between the substrate layer (A) and the first coating layer (B).

In one embodiment an optional coating composition is deposited onto the at least one surface of the substrate layer (A) as such that an optional additional coating layer is formed onto the at least one surface of the substrate layer (A). Said optional additional coating layer is then on one side in adherent contact with the at least one surface of the substrate layer (A) and on the other side in adherent contact with the first coating layer (B).

“Adherent contact” in this regard means that there is no further coating layer or adhesive layer between the at least one surface of the substrate layer (A) and the optional additional coating layer and the optional additional coating layer and the first coating layer (B).

Said optional additional coating layer can have a thickness of 5 to 300 nm or a thickness of 300 nm to 5 pm.

Said optional additional coating layer is usually applied in specific cases such as promoting the adhesion between the substrate layer (A) and the first coating layer (B), wetting of the first coating layer (B), promoting the optical performance of the layered structure or promoting the mechanical performance of the layered structure. It is, however, preferred that no optional additional coating layer is applied between the substrate layer and the first coating layer (B).

First coating layer (B)

The first coating layer (B) coated on at least one surface of the substrate layer (A) so that the first coating layer (B).

It is preferred that the first coating layer (B) is in adherent contact with at least one surface of the substrate layer (A). Thus, the first coating layer (B) usually is the inner layer of the multi-layer coating with adherent contact with at least one surface of the substrate layer (A). “Adherent contact” in this regard means that there is no further coating layer or adhesive layer between the at least one surface of the substrate layer (A) and the first coating layer (B).

The first coating layer (B) preferably has a thickness of 1 to 50 pm, preferably of 2 to 20 pm, more preferably 3 to 10 pm.

The first coating layer (B) comprises a first siloxane polymer (B-l). The first siloxane polymer (B-l) comprises monomer units selected from at least two different silane monomers, wherein at least one of the silane monomers includes an active group capable of achieving cross-linking to adjacent siloxane polymer chains, and wherein the adjacent siloxane polymer chains are crosslinked by means of said an active groups.

The first siloxane polymer (B-l) can comprise monomer units selected from 2 to 10, such as from 2 to 6, preferably from 2 to 4 different silane monomers. “Different” in this connection means that the silane monomers differ in at least one chemical moiety.

Active groups are preferably epoxy, alicyclic epoxy groups (e.g. glycidyl), vinyl, allyl, acrylate, methacrylate and silane groups and combinations thereof.

Thereby, the epoxy, alicyclic epoxy groups (e.g. glycidyl), vinyl, allyl, acrylate, methacrylate groups are capable of achieving cross-linking to adjacent siloxane polymer chains upon a thermal or radiation initiation, preferably in the presence of a suitable initiator such as a thermal or radical initiator.

Suitable thermal or radical initiators are preferably selected from tert-amyl peroxybenzoate, 4,4-azobis(4-cyanovaleric acid), 1,1'- azobis(cyclohexanecarbonitrile), benzoyl peroxide, 2,2-bis(tert-butylperoxy)butane, l,l-bis(tert-butylperoxy)cyclohexane, 2,2'-azobisisobutyronitrile (AIBN), 2,5- bis(tert-butylperoxy)-Z,S-dimethylhexane, 2,5-bis(tert-Butylperoxy)- 2,5 -dimethyl-3 -hexyne, bis(l -(tert-butylperoxy)- 1 -methylethyl)benzene, 1 , 1 -bis(tert- butylperoxy)-3,3,5- trimethylcyclohexane, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy isopropyl carbonate, bumene hydroperoxide, byclohexanone peroxide, bicumyl peroxide, lauroyl peroxide, 2,4- pentanedione peroxide, peracetic acid or potassium persulfate. Especially preferred is 2,2'-azobisisobutyronitrile (AIBN). The silane group is capable of achieving cross-linking to a carbon-carbon double bond, such as a vinyl or allyl group) of an adjacent siloxane polymer chains upon hydrosilylation, preferably in the presence of a suitable catalyst, such as a platinum (Pt)-based catalyst such as the Speier catalyst (FhPtC FhO), Karstedt’s catalyst (Pt(0)-l,3-divinyl-l,l,3,3-tetramethyldisiloxane complex solution) or a rhodium (Rh)-based catalyst such as Tris(triphenylphosphine)rhodium (I) chloride.

In one embodiment, the molar ratio between monomers containing a first active group, e.g. selected from epoxy, alicyclic epoxy groups (e. g. glycidyl), and vinyl and allyl groups, to monomers containing a second active group, e.g. selected from acrylate and methacrylate groups, varies in the range of 1 : 100 to 100: 1, in particular 1 :10 to 10: 1, for example 5: 1 to 1 :2 or 3:1 to 1 : 1.

In some embodiments, the components containing the second active group also be selected from acrylate and metacrylate containing compounds other than silane monomers, such as tetraethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, ditrimethylo Ipropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate and combinations thereof.

In some embodiments, the active group or active groups will be present in a concentration of about 1 to 35 % based on the molar portion of monomers.

Suitable silane monomers are preferably represented by formula (I) RJaSiX^a (I) wherein

R¹ is selected from hydrogen and a group comprising linear and branched alkyl, cycloalkyl, alkenyl, alkynyl, (alk)acrylate, epoxy, allyl, vinyl and alkoxy and aryl having 1 to 6 rings, and wherein the group is substituted or unsubstituted;

X is a hydrolysable group or a hydrocarbon residue; and a is an integer 1 to 3. The hydrolysable group is in particular an alkoxy group (cf. formula II).

The alkoxy groups of R¹ and/or the hydrolysable group X can be identical or different and preferably selected from the group of radicals having the formula -O-R² (II) wherein

R² stands for a linear or branched alkyl group having 1 to 10, preferably 1 to 6 carbon atoms, and optionally exhibiting one or two substituents selected from the group of halogen, hydroxyl, vinyl, epoxy and allyl. Most preferred are methoxy and ethoxy groups.

Especially preferred are di-, tri- or tetraalkoxysilanes comprising alkoxy groups according to formula (II).

Particularly suitable silane monomers are selected from the group of tetraethoxysilane (TEOS), tetramethoxysilane (TMS), methyltri ethoxy si lane (MTEOS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDEOS), dimethyldimethoxy silane (DMDMS), diphenyldimethoxy silane (DPDMS), 3- (Trimethoxysilyl)propylmethacrylate (MEMO), 3- (Triethoxysilyl)propylmethacrylate, 5-(Bicycloheptenyl)triethoxysilane (BCHTEOS), (3-Glycidoxypropyl)triethoxysilane, (3- Glycidoxypropyl)trimethoxy silane (GPTMS), (Heptadecafluoro- 1 , 1 ,2,2- tetrahydrodecyl)trimethoxy silane (F 17), (Heptadecafluoro- 1 , 1 ,2,2- tetrahydrodecyl)triethoxysilane, 1H,1H,2H,2H-Perfluorododecyltriethoxysilane, 1H, 1H,2H,2H-Perfluorododecyltrimethoxysilane, 1H, 1H,2H,2H- Perfluorooctyltriethoxysilane, 1H, 1H,2H,2H-Perfluorooctyltrimethoxysilane (F 13), 1H, 1H,2H,2H-Perfluoropentyltriethoxysilane, 1H, 1H,2H,2H-

Perfluoropentyltrimethoxysilane, 1H,1H,2H,2H-Perfluorotetradecyltriethoxysilane, 1H,1H,2H,2H-Perfluorotetradecyltrimethoxysilane, allyltrimethoxysilane (allylTMS), allyltriethoxysilane (allylTEOS), vinyltrimethoxysilane, vinyltriethoxysilane, (3-Glycidopropyl)dimethoxymethylsilane (Me-GPTMS), methacryloxypropylmethyldimethoxysilane (Me-MEMO), phenylmethyldimethoxysilane (PMDMS), Bis[(2,2,3,3,4,4- hexafluorobutyl)propanoic ester]-3-aminopropyltrimethoxysilane or mixtures thereof.

Preferred are silane monomers are selected from the group of phenylmethyl dimethoxysilane (PMDMS), 3-(Trimethoxysilyl)propylmethacrylate (MEMO) and (3-Glycidoxypropyl)trimethoxysilane (GPTMS).

Said silane monomers are preferably present in the in the siloxane polymer in a molar amount of 50 to 100 mol%, preferably of 50 to 99 mol%, still more preferably of 65 to 97 mol%.

In one embodiment the at least two different silane monomers of the first siloxane polymer (B-l) comprise at least one bi-silane.

Suitable bi-silanes are preferably represented by formula (III) (R³)₃Si-Y-Si(R⁴)₃, (III) wherein

R³ and R⁴ are independently selected from hydrogen and a group consisting of linear or branched alkyl, cycloalkyl, alkenyl, alkynyl, (alk)acrylate, epoxy, allyl, vinyl, alkoxy and aryl having 1 to 6 rings, and wherein the group is substituted or unsub stitued; and

Y is a linking group selected from bivalent unsubstituted or substituted aliphatic and aromatic groups, such as alkylene, arylene, -O-alkylene-O-; -O-arylene-O-; alkylene- O-alkylene, arylene-O-arylene; alkylene-Z¹C(=O)Z²-alkylene, arylene-Z¹C(=O)Z²- arylene and -O-alkylene-Z¹C(=O)Z²-alkylene-O-; -O-arylene-Z¹C(=O)Z²-arylene-O- , wherein Z¹ and Z² are each selected from a direct bond or -O-. In the bivalent “alkylene” groups and other similar aliphatic groups, the alkyl residue (or residue derived from an alkyl moiety) stands for 1 to 10, preferably 1 to 8, or 1 to 6 or even 1 to 4 carbon atoms, examples include ethylene and methylene and propylene.

“Arylene” stands for an aromatic bivalent group containing typically 1 to 3 aromatic rings, and 6 to 18 carbon atoms. Such groups are exemplified by phenylene (e.g. 1,4- phenylene and 1,3-phenylene groups) and biphenylene groups as well as naphthylene or anthracenylene groups.

The alkylene and arylene groups can optionally be substituted with 1 to 5 substituents selected from hydroxy, halo, vinyl, epoxy and allyl groups as well as alkyl, aryl and aralkyl groups.

Preferred alkoxy groups contain 1 to 4 carbon atoms. Examples are methoxy and ethoxy.

The term “phenyl” includes substituted phenyls such as phenyltrialkoxy, in particular phenyltrimethoxy or tri ethoxy, and perfluorophenyl. The phenyl as well as other aromatic or alicyclic groups can be coupled directly to a silicon atom, or they can be coupled to a silicon atom via a methylene or ethylene bridge.

Exemplary bi-silanes include 1,2-Bis(triethoxysilyl)ethane (BTESE), 1,2- Bis(trimethoxysilyl)ethane (MEOS) and mixtures thereof.

It is preferable to have the bi-silane present in the siloxane polymer in a molar amount of 0 to 50 mol%, preferably of 1 to 50 mol%, still more preferably of 3 to 35 mol%. It is especially preferred that the at least two silane monomers are selected from mixture of two or more of the group of 1,2-Bis(tri ethoxy silyljethane (BTESE), phenylmethyl dimethoxysilane (PMDMS), 3-(Trimethoxysilyl)propylmethacrylate (MEMO) and (3-Glycidoxypropyl)trimethoxysilane (GPTMS).

The first composition comprising a siloxane polymer (B-l) is preferably formed by a method comprising the steps of

• Admixing the at least two different silane monomers, preferably as described above or below, in a first solvent to form a mixture;

• Subjecting the mixture to an at least partial hydrolysis of the monomers in the presence of a catalyst, whereby the hydrolysed monomers are at least partially polymerized and cross-linked;

• Optionally changing the first solvent to a second solvent;

• Optionally subjecting the mixture to further crosslinking by hydrosilylation, thermal or radiation initiation.

The first solvent is preferably selected from the group of acetone, tetrahydrofuran (THF), toluene, 1 -propanol, 2-propanol, methanol, ethanol, water (H2O), cyclopentanone, acetonitrile, propylene glycol propyl ether, methyl -tert-butyl ether (MTBE), propylene glycol monomethylether acetate (PGMEA), methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethylether (PGME) and propylene glycol propyl ether (PnP).

The at least two different silane monomers can be admixed in the first solvent at any suitable temperature for solving the silane monomers. Usually, room temperature suffices.

In the next method step the mixture is subjected to an at least partial hydrolysis in the presence of a catalyst. Suitable catalysts are acidic catalysts, basic catalysts, or other catalysts.

Acidic catalysts are preferably selected from nitric acid (HNO3), sulfuric acid (H2SO4), formic acid (HCOOH), hydrochloric acid (HC1), sulfonic acid, hydrogen fluoride (HF), acetic acid (CH3COOH), trifluoromethanesulfonic acid or -toluene sulfonic acid. Especially preferred acidic catalysts are nitric acid (HNO3) hydrochloric acid (HC1) and formic acid (HCOOH).

Basic catalysts are preferably selected from triethylamine (TEA), ammonium hydroxide (NH4OH), tetraethylammonium hydroxide (TEAH), tetramethylammonium hydroxide (TMEA), l,4-diazabicyclo[2.2.2]octane, imidazole and diethylenetriamine.

Other catalysts are preferably selected from 2,2,3,3,4,4,5,5-octafluoropentylacrylate, poly(ethylene glycol) 200, poly(ethylene glycol) 300 and n-butylated melamine formaldehyde resin.

The hydrolysis step is preferably performed at a temperature of from 20 to 80°C for 1 to 24 hours, such as at room temperature overnight.

During the hydrolysis step the silane monomers are at least partially hydrolysed. Said at least partially hydrolysed silane monomers then are at least partially polymerized, preferably by condensation polymerization and crosslinked to form a siloxane polymer.

Said polysiloxane usually has a relatively low molecular weight in range of about 500 to 2000 g/mol.

According to a preferable embodiment the subjecting the mixture to an at least partial hydrolysis includes refluxing. A typical refluxing time is 2 h.

The first solvent can be changed to a second solvent in an optional further method step after the hydrolysis step. The optional solvent change is advantageous, since it assists the removal of water and alcohols formed during hydrolysis of the silane monomers. In addition, it improves the properties of the final siloxane polymer solution when used as coating layer(s) on the substrate.

The second solvent is preferably selected from the group of propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), 1 -ethanol, 2-ethanol (IP A), acrylonitrile diacetone alcohol (DAA) or propylene glycol n-propyl ether (PnP).

The mixture comprising the siloxane polymer can be further subjected to a crosslinking step after the hydrolysis step. Thereby, the siloxane polymer is preferably at least partially crosslinked by hydrosilylation, thermal or radiation initiation.

In the present context, the term “partially crosslinked” means that the polymer is capable of further crosslinking at conditions conducive to cross-linking. In practice, the polymer still contains at least some reactive, crosslinking groups after the first polymerisation step. The further crosslinking, which typically takes place after deposition of the partially crosslinked composition on a substrate, will be described below.

The siloxane polymer is preferably at least partially crosslinked by hydrosilylation, thermal or radiation initiation using catalysts as described above.

Thereby, thermal crosslinking is preferably conducted at temperatures in the range of about 30 to 200 °C.

Typically cross-linking is carried out at refluxing conditions of the solvent.

To improve resolution of the material when applied to photolithography, the siloxane polymer can be optionally partially cross-linked during polymerization, in particular during or immediately after condensation polymerization. Various methods can be used for achieving cross-linking. For example, cross-linking method where two chains are joined via reactive groups not affecting any of the active groups intended for the UV photolithography can be employed. To mention an example, hydrosilylation for example using a proton on one chain reacting with a double bond on another chain will achieve cross-linking of desired kind. Another example is cross-linking through double bonds or epoxy groups.

Different active groups are preferably used for cross-linking and for photolithography. Thus, the cross-linking of the siloxane polymer can be achieved with an active group having double bonds or epoxy groups or both, such as epoxy, vinyl or allyl or methacrylate group using radical initiators and photoacid generators.

Epoxy groups can be employed for UV-lithography and vice versa. The proportion of active groups required for cross-linking is generally smaller than for UV lithography, e.g. about 0.1 to 10 mol%, based on the monomers, for cross-linking and about 5 to 50 mol%, based on the monomers, for UV lithography.

The amount of the initiator added to the reaction mixture/ solution is generally about 0.1 to 10 wt%, preferably about 0.5 to 5 wt%, calculated from the total weight of the siloxane polymer.

As a result of the partial cross-linking, the molecular weight will typically be 2- to 10-folded. Thus from a molecular weight in the range of about 500 to 2000 g/mol, the crosslinking will increase it above 3000, preferably to 4000 to 20000 g/mol.

Optionally, resulting free Si-OH groups present in backbone of the siloxane polymer can be protected by an end-capping. For end capping, the free Si-OH groups are reacted with silanes such as methyldichlorofluorosilane (CEFSiCHs, methylfluorodimethoxysilane ((MeO^SiFCH?), 3 -chloropropyltrimethoxy silane (Cl(CH2)3Si(OMe)3), ethyltrimethoxysilane (ETMS), or trimethylchlorosilane (CISiMes) in presence of a catalyst such as tri ethylaluminium (TEA) or imidazole. The amount of catalyst varies from 1.5 to 2 wt% of total solid. The reaction time varies from 40 to 45 min. Other additives typically introduced into the first composition comprising a siloxane polymer (B-l) include chemicals that can further modify the final surface properties of coated and cured film or improve wettability/adhesion properties of the coating layer (B) to the substrate layer (A) or the other coating layer (C) or improve coating drying and packing behavior during deposition and drying to reach good visual quality.

These additives can be surfactants, defoamers, antifouling agents, wetting agents etc. Examples of such additives include: BYK-301, BYK-306, BYK-307, BYK-308, BYK-333, BYK-051, BYK-036, BYK-028, BYK-057A, BYK-011, BYK-055, BYK-036, BYK-067A, BYK-088, BYK-302, BYK-310, BYK-322, BYK-323, BYK-331, BYK-333, BYK-341, BYK-345, BYK-348, BYK-370, BYK-377, BYK- 378, BYK-381, BYK-390, BYK-3700, all commercially available from BYK.

The additives are preferably present in an amount of 0.01-5 wt% by weight, more preferably 0.1 to 1 wt% of the total weight of the solids.

Before further condensation the excess of water is preferably removed from the material and at this stage it is possible to make a solvent exchange to another synthesis solvent if desired. This other synthesis solvent may function as the final or one of the final processing solvents of the siloxane polymer. The residual water and alcohols and other by-products may be removed after the further condensation step is finalized. Additional processing solvent(s) may be added during the formulation step to form the final processing solvent combination. Additives such as thermal initiators, radiation sensitive initiators, sensitizers, surfactants, and other additives may be added prior to final filtration of the siloxane polymer. After the formulation of the composition, the polymer is ready for processing in, for example, roll-to-roll film deposition or in a lithographic process.

By adjusting the hydrolysis and condensation conditions it is possible to control the concentration/ content of the group capable of being deprotonated (e. g. an OH- group) and any residual leaving groups from the silane precursors (e. g. alkoxy groups) of the siloxane polymer composition and also to control the final molecular weight of the siloxane polymer. This greatly affects dissolution of the siloxane polymer material into the aqueous based developer solution. Furthermore, the molecular weight of the polymer also greatly effects on the dissolution properties of the siloxane polymer into developer solutions.

Thus, for example, it has been found that when the final siloxane polymer has a high content of hydroxyl groups remaining and a low content of alkoxy (e.g. ethoxy) groups, the final siloxane polymer can be dissolved into an alkaline-water developer solution (egg. tetra methyl ammonium hydroxide; TMAH, or potassium hydroxide; KOH).

On the other hand, if the remaining alkoxy-group content of the final siloxane polymer is high and it contains hardly any OH-groups, the final siloxane polymer has a very low solubility in an alkaline-water developer of the above kind. The OH- groups or other functional groups, such as amino (NH2), thiol (SH), carboxyl, phenol or similar that result in solubility to the alkaline developer systems, can be attached directly to the silicon atoms of the siloxane polymer backbone or optionally attached to organic functionalities attached into the siloxane polymer backbone to filrther facilitate and control the alkaline developer solubility.

After synthesis, the siloxane polymer composition can be diluted using a proper solvent or solvent combination to give a solid content which in film deposition will yield the pre-selected film thickness.

Usually, a further amount of an initiator molecule compound is added to the siloxane composition after synthesis. The initiator, which can be optionally similar to the one added during polymerization, is used for creating a species that can initiate the polymerization of the “active” filnctional group in the UV curing step. Thus, in case of an epoxy group, cationic or anionic initiators can be used. In case of a group with double bonds as “active” functional group in the synthesized material, radical initiators can be employed. Also thermal initiators (working according to the radical, cationic or anionic mechanism) can be used to facilitate the crosslinking of the “active” filnctional groups. The choice of a proper combination of the photoinitiators and sensitizers also depends on the used exposure source (wavelength). Furthermore, the selection of the used sensitizer depends on the selected initiator type.

The concentration of the thermal or radiation initiator and sensitizers in the composition is generally about 0.1 to 10 %, preferably about 0.5 to 5 %, calculated from the mass of the siloxane polymer.

The composition as described above may comprise solid nanoparticles or other compounds in an amount of between 1 and 50 wt-% of the composition. The nanoparticles (or similar nano-, or microscale rods, crystals, spheres, dots, buds etc.) are in particular selected from the group of light scattering, light absorbing, light emitting and/or conductive pigments, dyes, organic and inorganic phosphors, oxides, quantum dots, polymers or metals.

The first composition comprising the siloxane polymer (B-l) is then deposited onto the onto at least one surface of the substrate to form a first coating layer (B).

It is preferred that the first coating layer (B) is in adherent contact with the at least one surface of the substrate.

Suitable deposition methods include spin-on, clip, spray, ink-jet, roll-to-roll, gravure, reverse gravure, bar coating, slot, flexo-graphic, curtain, screen printing coating methods, extrusion coating, dip coating, flow coating or slit coating. The deposited first composition comprising the siloxane polymer (B-l) forms the coating layer (B) on the surface of the substrate (A). Typically, after deposition, or during the deposition step, the solvent is evaporated and the film coating layer (B) dried, preferably by thermal drying or optionally by vacuum and/or thermal drying combined. This step is also referred to as pre-curing.

In a second, subsequent step the coating layer (B) is cured to final hardness by using thermal curing at elevated temperature or UV exposure followed by thermal curing at elevated temperature.

In one embodiment, the pre-curing and the final curing steps are combined by carrying out heating by using an increasing heating gradient. In addition to the thermal cure only process, the curing can be performed in three steps, the process comprising thermal pre-cure and UV-cure followed by final thermal cure. It is also possible to apply a two steps curing process where thermal pre-cure is followed by UV-cure. In such a case no final thermal cure is preferably applied after UV-cure).

According to a particular embodiment the method further includes developing the deposited film. In one embodiment, developing comprises exposing (full area or selective exposure using photomask or reticle or laser direct imaging) the deposited first siloxane polymer composition to UV light. The step of developing is typically carried out after any pre-curing step and before a final curing step.

Thus, in one embodiment the method comprises the steps of

- pre-curing or drying the first coating layer (B) deposited on the substrate (A); optionally exposing the thus coating layer (B); optionally developing the thus obtained coating layer (B); and curing the coating layer (B). Exemplary epoxy -functional group containing monomers include (3- glycidoxypropyl)trimethoxy silane, l-(2-(Trimethoxysilyl)ethyl)cyclohexane-3,4- epoxide, (3-glycidoxypropyl)triethoxysilane, (3- glycidoxypropyl)tripropoxysilane, 3-glycidoxypropyltri(2-methoxyethoxy)silane, 2,3-epoxypropyltriethoxysilane, 3,4- epoxybutyltriethoxysilane, 4,5- epoxypentyltriethoxysilane, 5,6- epoxyhexyltriethoxysilane, 5,6- epoxyhexyltrimethoxysilane, 2-(3,4- epoxycy cl ohexyl)ethyltri ethoxy silane, 2-(3,4- epoxy cy cl ohexyl)ethyltrimethoxy silane, 4-(trimethoxy silyl)butane- 1 ,2-epoxide.

Further examples of functionalized compounds are acrylate and metacrylate compounds, such as tetraethylene glycol diacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, tricyclodecane dimethanol diacrylate, Tris(2- hydroxyethylisocyanurate) Di / Triacrylate and dipentaerythritol hexaacrylate and combinations thereof. Such acrylates as commercially available e.g. as Miramer acrylates from Miwon. Such compounds can be used as part of the silane compositions.

According to a particular embodiment the method further includes curing the first composition comprising the siloxane polymer (B-l).

The thickness of the first coating layer (B) on the substrate (A) (i.e. the film thickness) may range from 1 to 50 pm, preferably of 2 to 20 pm, more preferably 3 to 10 pm.

The coating layer (B) preferably is a flexible hard coat layer.

It is preferred that the hardness of the coating layer (B) is greater than 3H, over 4H, over 5H, over 6H or even over 7H as determined by ASTM D3363-00, Elcometer tester. Preferably the coating layer (B) has an adhesion of 4B-5B, as tested by ASTM D3359-09, Crosshatch tester.

Further, the coating layer (B) preferably has a scratch resistance as evidenced by no visual scratches on a Taber linear abrasion test (Using Linear Abraser from Taber Industries) carried out at up to 2000 linear cycles with BonStar steel wool #0000, at 500g weight, 2x2 cm head size, 2.0-inch stroke length, 60 cycles/min.

Second coating layer (C)

The second coating layer (C) coated on at least one surface of the first coating layer (B) so that the second coating layer (C) is in adherent contact with at least one surface of the first coating layer (B). Thus, the second coating layer (C) usually is an outer layer of the multi-layer coating with adherent contact with at least one surface of the first coating layer (B) as such that the first coating layer (B) is sandwiched between the substrate layer (A) and the second coating layer (C). “Adherent contact” in this regard means that there is no further coating layer or adhesive layer between the at least one surface of the fist coating layer (B) and the second coating layer (C).

The second coating layer (C) preferably has a thickness of 10 nm to 10 pm, preferably of 25 nm to 8 pm, more preferably 50 nm to 5 pm.

The second coating layer (C) comprises one or more, such as one, two, three or four, preferably one to three, more preferably one or two, most preferably two second siloxane polymer(s) (C-l). In the case that the second coating layer (C) comprises more than one second siloxane polymers (C-l) said siloxane polymers differ in at least one property. Said at least one property can be e.g. differences in the silane monomers and/or differences in the molecular weight.

The following discussion can be applied for each of the second siloxane polymers (C-l): The second siloxane polymers (C-l) preferably comprise monomer units selected from one or more silane monomers.

Thereby, at least one of the silane monomers can include an active group capable of achieving cross-linking to adjacent siloxane polymer chains.

Then, the adjacent siloxane polymer chains are usually crosslinked by means of said active groups.

The second siloxane polymers (C-l) can comprise monomer units selected from 1 to 10, such as from 1 to 6, preferably from 1 to 4, more preferably 1 or 2 different silane monomers. “Different” in this connection means that the silane monomers differ in at least one chemical moiety.

Active groups, if present, are preferably epoxy, alicyclic epoxy groups (e.g. glycidyl), vinyl, allyl, acrylate, methacrylate and silane groups and combinations thereof.

Particularly suitable silane monomers are selected from the group of tetraethoxysilane (TEOS), tetramethoxysilane (TMS), methyltri ethoxy si lane (MTEOS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDEOS), dimethyldimethoxy silane (DMDMS), diphenyldimethoxy silane (DPDMS), 3- (Trimethoxysilyl)propylmethacrylate (MEMO), 3- (Triethoxysilyl)propylmethacrylate, 5-(Bicycloheptenyl)triethoxysilane (BCHTEOS), (3-Glycidoxypropyl)triethoxysilane, (3- Glycidoxypropyl)trimethoxy silane (GPTMS), (Heptadecafluoro- 1 , 1 ,2,2- tetrahydrodecyl)trimethoxy silane, (Heptadecafluoro- 1 , 1 ,2,2- tetrahydrodecyl)triethoxysilane (Fl 7), 1H,1H,2H,2H- Perfluorododecyltriethoxysilane, 1H,1H,2H,2H-Perfluorododecyltrimethoxysilane, 1H, 1H,2H,2H-Perfluorooctyltriethoxysilane, 1H, 1H,2H,2H- Perfluorooctyltrimethoxysilane, 1H,1H,2H,2H-Perfluoropentyltriethoxysilane, 1H, 1H,2H,2H-Perfluoropentyltrimethoxysilane, 1H, 1H,2H,2H- Perfluorotetradecyltriethoxysilane, 1H, 1H,2H,2H- Perfluorotetradecyltrimethoxysilane, allyltrimethoxysilane (allylTMS), allyltriethoxysilane (allylTEOS), vinyltrimethoxysilane, vinyltriethoxysilane, (3- Glycidopropyl)dimethoxymethylsilane (Me-GPTMS), methacryloxypropylmethyldimethoxysilane (Me-MEMO), phenylmethyldimethoxysilane (PMDMS), Bis[(2,2,3,3,4,4- hexafluorobutyl)propanoic ester]-3-aminopropyltrimethoxysilane or mixtures thereof.

Preferred are silane monomers are selected from the group of tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMS).

Y is a linking group selected from bivalent unsubstituted or substituted aliphatic and aromatic groups, such as alkylene, arylene, -O-alkylene-O-; -O-arylene-O-; alkylene- O-alkylene, arylene-O-arylene; alkylene-Z¹C(=O)Z²-alkylene, arylene-Z¹C(=O)Z²- arylene and -O-alkylene-Z¹C(=O)Z²-alkylene-O-; -O-arylene-Z¹C(=O)Z²-arylene-O- , wherein Z¹ and Z² are each selected from a direct bond or -O-.

In the bivalent “alkylene” groups and other similar aliphatic groups, the alkyl residue (or residue derived from an alkyl moiety) stands for 1 to 10, preferably 1 to 8, or 1 to 6 or even 1 to 4 carbon atoms, examples include ethylene and methylene and propylene.

It is preferable to have the bi-silane present in the siloxane polymer in a molar amount of 0 to 50 mol%, preferably of 1 to 50 mol%, still more preferably of 3 to 35 mol%.

It is especially preferred that the at least one silane monomers is selected from tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMS). The second composition comprising at least one second siloxane polymer (C-l) is preferably formed by a method comprising the steps of

• Optionally changing the first solvent to a second solvent;

In the case that the second composition comprises more than one second siloxane polymer (C-l) the above steps are repeated for each one of the second siloxane polymer (C-l).

In the next method step the mixture is subjected to an at least partial hydrolysis in the presence of a catalyst.

Suitable catalysts are acidic catalysts, basic catalysts or other catalysts. Acidic catalysts are preferably selected from nitric acid (HNO3), sulfuric acid (H2SO4), formic acid (HCOOH), hydrochloric acid (HC1), sulfonic acid, hydrogen fluoride (HF), acetic acid (CH3COOH), trifluoromethanesulfonic acid or -toluene sulfonic acid. Especially preferred acidic catalysts are nitric acid (HNO3), formic acid (HCOOH) and hydrochloric acid (HC1).

The first solvent can be changed to a second solvent in an optional further method step after the hydrolysis step. The optional solvent change is advantageous, since it assists the removal of water and alcohols formed during hydrolysis of the silane monomers. In addition, it improves the properties of the final siloxane polymer solution when used as coating layer(s) on the substrate. The second solvent is preferably selected from the group of propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), 1 -ethanol, 2-ethanol (IP A), acrylonitrile diacetone alcohol (DAA) or propylene glycol n-propyl ether (PnP).

Typically cross-linking is carried out at refluxing conditions of the solvent.

Epoxy groups can be employed for UV-lithography and vice-versa. The proportion of active groups required for cross-linking is generally smaller than for UV lithography, e.g. about 0.1 to 10 mol%, based on the monomers, for cross-linking and about 5 to 50 mol%, based on the monomers, for UV lithography.

As a result of the partial cross-linking, the molecular weight will typically be 2- to 10-folded. Thus, from a molecular weight in the range of about 500 to 2000 g/mol, the crosslinking will increase it above 3000, preferably to 4000 to 20000 g/mol.

Optionally, resulting free Si-OH groups present in backbone of the siloxane polymer can be protected by an end-capping. For end capping, the free Si-OH groups are reacted with silanes such as methyldichlorofluorosilane (CEFSiCHs, methylfluorodimethoxysilane ((MeO^SiFCH?), 3 -chloropropyltrimethoxy silane (Cl(CH2)3Si(OMe)3), ethyltrimethoxysilane (ETMS), or trimethylchlorosilane (CISiMes) in presence of a catalyst such as tri ethylaluminium (TEA) or imidazole. The amount of catalyst varies from 1.5 to 2 wt% of total solid. The reaction time varies from 40 to 45 min. Other additives typically introduced into the second composition comprising the fluoropoly ether compound and the at least one second siloxane polymer (C-l) include chemicals that can further modify the final surface properties of coated and cured film or improve wettability/adhesion properties of the coating layer (B) to the substrate layer (A) or the other coating layer (C) or improve coating drying and packing behavior during deposition and drying to reach good visual quality.

These additives can be surfactants, defoamers, antifouling agents, wetting agents etc. Examples of such additives include: BYK-301, BYK-306, BYK-307, BYK-308, BYK-333, BYK-051, BYK-036, BYK-028, BYK-057A, BYK-011, BYK-055, BYK-036, BYK-067A, BYK-088, BYK-302, BYK-310, BYK-322, BYK-323, BYK-331, BYK-333, BYK-341, BYK-345, BYK-348, BYK-370, BYK-377, BYK- 378, BYK-381, BYK-390, BYK-3700.

Before further condensation the excess of water is preferably removed from the material and at this stage it is possible to make a solvent exchange to another synthesis solvent if desired. This other synthesis solvent may function as the final or one of the final processing solvents of the siloxane polymer. The residual water and alcohols and other by-products may be removed after the further condensation step is finalized. Additional processing solvent(s) may be added during the formulation step to form the final processing solvent combination. Additives such as thermal initiators, radiation sensitive initiators, sensitizers, surfactants and other additives may be added prior to final filtration of the siloxane polymer. After the formulation of the composition, the polymer is ready for processing in, for example, roll-to-roll film deposition or in a lithographic process.

By adjusting the hydrolysis and condensation conditions it is possible to control the concentration/ content of the group capable of being deprotonated (e.g. an OH- group) and any residual leaving groups from the silane precursors (e.g. alkoxy groups) of the siloxane polymer composition and also to control the final molecular weight of the siloxane polymer. This greatly affects dissolution of the siloxane polymer material into the aqueous based developer solution. Furthermore, the molecular weight of the polymer also greatly effects on the dissolution properties of the siloxane polymer into developer solutions.

As mentioned above the method for preparing the second siloxane polymer (C-l) is repeated for each one of the second siloxane polymer (C-l).

The second siloxane polymer (C-l) can be diluted using a proper solvent or solvent combination to give a solid content which in film deposition will yield the preselected film thickness.

The solvent or solvent combination can comprise a fluorinated solvent such as methoxy-nonafluorobutane or l,l,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether. Usually, a further amount of an initiator molecule compound is added to the siloxane composition after synthesis. The initiator, which can be optionally similar to the one added during polymerization, is used for creating a species that can initiate the polymerization of the “active” functional group in the UV curing step. Thus, in case of an epoxy group, cationic or anionic initiators can be used. In case of a group with double bonds as “active” functional group in the synthesized material, radical initiators can be employed. Also, thermal initiators (working according to the radical, cationic or anionic mechanism) can be used to facilitate the crosslinking of the “active” functional groups. The choice of a proper combination of the photoinitiators and sensitizers also depends on the used exposure source (wavelength). Furthermore the selection of the used sensitizer depends on the selected initiator type.

The second composition is deposited onto the least one surface of the substrate to form the second coating layer (C) in adherent contact with the at least one surface of the first coating layer (B).

Suitable deposition methods include spin-on, clip, spray, ink-jet, roll-to-roll, gravure, reverse gravure, bar coating, slot, flexo-graphic, curtain, screen printing coating methods, extrusion coating, dip coating, flow coating or slit coating.

The deposited second composition forms the second coating layer (C) on the surface of the first coating layer (B). Typically, after deposition, or during the deposition step, the solvent is evaporated and the second coating layer (C) dried, preferably by thermal drying or optionally by vacuum and/or thermal drying combined. This step is also referred to as pre-curing. In a second, subsequent step the second coating layer (C) is cured to final hardness by thermal curing at elevated temperature or by using UV exposure followed by thermal curing at elevated temperature.

According to a particular embodiment the method further includes developing the deposited film. In one embodiment, developing comprises exposing (full area or selective exposure using photomask or reticule or laser direct imaging) the deposited first siloxane polymer composition to UV light. The step of developing is typically carried out after any pre-curing step and before a final curing step.

Thus, in one embodiment the method comprises the steps of

- pre-curing or drying the second coating layer (C) deposited on the first coating layer (A); optionally exposing the thus obtained second coating layer (C); optionally developing the thus obtained second coating layer (C); and curing the second coating layer (C).

Exemplary epoxy -functional group containing monomers include (3- glycidoxypropyl)trimethoxy silane, l-(2-(Trimethoxysilyl)ethyl)cyclohexane-3,4- epoxide, (3-glycidoxypropyl)triethoxysilane, (3- glycidoxypropyl)tripropoxysilane, 3-glycidoxypropyltri(2-methoxyethoxy)silane, 2,3-epoxypropyltriethoxysilane, 3,4- epoxybutyltriethoxysilane, 4,5- epoxypentyltriethoxysilane, 5,6- epoxyhexyltriethoxysilane, 5,6- epoxyhexyltrimethoxysilane, 2-(3,4- epoxy cy cl ohexyl)ethyltri ethoxy silane, 2-(3,4- epoxy cy cl ohexyl)ethyltrimethoxy silane, 4-(trimethoxy silyl)butane- 1 ,2-epoxide.

Further examples of functionalized compounds are acrylate and metacrylate compounds, such as tetraethylene glycol diacrylate, trimethylo Ipropane triacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate and combinations thereof. Such compounds can be used as part of the silane compositions.

According to a particular embodiment the method further includes curing the second composition comprising fluoropolyether compound.

The thickness of the second coating layer (C) on the first coating layer (B) (i.e. the film thickness) may range from 10 nm to 10 pm, preferably of 25 nm to 8 pm, more preferably 50 nm to 5 pm.

The second coating layer (C) preferably is an anti -reflective layer.

It is preferred that the second coating layer (C) a refractive index of not more than 1.30, such as in the range of 1.26 - 1.30.

layer (D)

In some embodiments the layered structure can comprise an additional third coating layer (D) coated on at least one surface of the second coating layer (C) so that the third coating layer (D) is in adherent contact with at least one surface of the second coating layer (C). “Adherent contact” in this regard means that there is no further coating layer or adhesive layer between the at least one surface of the third substrate layer (D) and the second coating layer (C).

The third coating layer (D) preferably has a thickness of 10 nm to 10 pm, preferably of 15 nm to 8 pm, more preferably 20 nm to 5 pm. Preferably the third coating layer (D) comprises a siloxane polymer and optionally a fluoropolyether compound.

In one embodiment the third coating layer (D) preferably is an easy-to-clean coating layer comprising a siloxane polymer as described in WO 2016/146895 or WO 2020/099290. The disclosure of both documents is enclosed herein by reference in their entirety.

In another embodiment the third coating layer (D) comprises a third siloxane polymer (D-l) which comprises side chains comprising one or more fluorinated carbon groups.

The third siloxane polymer (D-l) comprises monomer units selected from at least one silane monomers.

The third siloxane polymer (D-l) can comprise monomer units selected from 1 to 10, such as from 1 to 6, preferably from 1 to 4 different silane monomers. “Different” in this connection means that the silane monomers differ in at least one chemical moiety.

In one embodiment at least one of the silane monomers includes an active group capable of achieving cross-linking to adjacent siloxane polymer chains, and wherein the adjacent siloxane polymer chains are crosslinked by means of said an active groups.

Suitable thermal or radical initiators are preferably selected from tert-amyl peroxybenzoate, 4,4-azobis(4-cyanovaleric acid), 1,1'- azobis(cyclohexanecarbonitrile), benzoyl peroxide, 2,2-bis(tert-butylperoxy)butane, l,l-bis(tert-butylperoxy)cyclohexane, 2,2'-azobisisobutyronitrile (AIBN), 2,5- bis(tert-butylperoxy)-Z,S-dimethylhexane, 2,5-bis(tert-Butylperoxy)- 2,5 -dimethyl-3 -hexyne, bis(l -(tert-butylperoxy)- 1 -methylethyl)benzene, 1 , 1 -bis(tert- butylperoxy)-3,3,5- trimethylcyclohexane, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy isopropyl carbonate, bumene hydroperoxide, byclohexanone peroxide, bicumyl peroxide, lauroyl peroxide, 2,4- pentanedione peroxide, peracetic acid or potassium persulfate. Especially preferred is 2,2'-azobisisobutyronitrile (AIBN).

The silane group is capable of achieving cross-linking to a carbon-carbon double bond, such as a vinyl or allyl group) of an adjacent siloxane polymer chains upon hydrosilylation, preferably in the presence of a suitable catalyst, such as a platinum (Pt)-based catalyst such as the Speier catalyst (EEPtCle.EEO), Karstedt’s catalyst (Pt(0)-l,3-divinyl-l,l,3,3-tetramethyldisiloxane complex solution) or a rhodium (Rh)-based catalyst such as Tris(triphenylphosphine)rhodium (I) chloride.

X is a hydrolysable group or a hydrocarbon residue; and a is an integer 1 to 3.

The hydrolysable group is in particular an alkoxy group (cf. formula II).

Especially preferred are di-, tri- or tetraalkoxysilanes comprising alkoxy groups according to formula (II). Particularly suitable silane monomers are selected from the group of tetraethoxysilane (TEOS), tetramethoxysilane (TMS), methyltri ethoxy si lane (MTEOS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDEOS), dimethyldimethoxy silane (DMDMS), diphenyldimethoxy silane (DPDMS), 3- (Trimethoxysilyl)propylmethacrylate (MEMO), 3- (Triethoxysilyl)propylmethacrylate, 5-(Bicycloheptenyl)triethoxysilane (BCHTEOS), (3-Glycidoxypropyl)triethoxysilane, (3- Glycidoxypropyl)trimethoxysilane (GPTMS), allyltrimethoxysilane (allylTMS), allyltriethoxysilane (allylTEOS), vinyltrimethoxysilane (VTMS), vinyltriethoxysilane, (3-Glycidopropyl)dimethoxymethylsilane (Me-GPTMS), methacryloxypropylmethyldimethoxysilane (Me-MEMO), phenylmethyldimethoxysilane (PMDMS), Bis[(2,2,3,3,4,4- hexafluorobutyl)propanoic ester]-3-aminopropyltrimethoxysilane or mixtures thereof.

Preferred are silane monomers are selected from the group of tetraethoxysilane (TEOS), phenylmethyldimethoxysilane (PMDMS), 3- (Trimethoxysilyl)propylmethacrylate (MEMO), methyltrimethoxysilane (MTMS), vinyltrimethoxysilane (VTMS) and (3-Glycidoxypropyl)trimethoxysilane (GPTMS).

In one embodiment the at least one silane monomers of the third siloxane polymer (D-l) comprise at least one bi-silane.

The alkylene and arylene groups can optionally be substituted with 1 to 5 substituents selected from hydroxy, halo, vinyl, epoxy, and allyl groups as well as alkyl, aryl and aralkyl groups.

The term “phenyl” includes substituted phenyls such as phenyltrialkoxy, in particular phenyltrimethoxy or tri ethoxy, and perfluorophenyl. The phenyl as well as other aromatic or alicyclic groups can be coupled directly to a silicon atom or they can be coupled to a silicon atom via a methylene or ethylene bridge. Exemplary bi-silanes include 1,2-Bis(triethoxysilyl)ethane (BTESE), 1,2- Bis(trimethoxysilyl)ethane (MEOS) and mixtures thereof.

It is preferable to have the bi-silane present in the siloxane polymer in a molar amount of 0 to 45 mol%, preferably of 1 to 45 mol%, still more preferably of 3 to 30 mol%.

Additionally, the third siloxane polymer comprises (D-l) at least one, such as 1 to 10, preferably 1 to 6, more preferably 1 or 2, most preferably one fluorinated monomer, which is capable of forming side chains comprising one or more fluorinated carbon groups.

Such fluorinated monomer can be a fluorinated silane monomer which is preferably represented by formula (I)

RJaSiX^a (I) wherein

R¹ is selected from a group comprising linear and branched alkyl, cycloalkyl, alkenyl, alkynyl, (alk)acrylate, epoxy, allyl, vinyl and alkoxy and aryl having 1 to 6 rings, preferably a linear or branched alkyl, and wherein the group is substituted with one or more fluorine atoms;

X is a hydrolysable group or a hydrocarbon residue; and a is an integer 1 to 3.

The hydrolysable group is in particular an alkoxy group (cf. formula II).

Examples of such silane monomers are e.g. (Heptadecafluoro-1, 1,2,2- tetrahydrodecyl)trimethoxy silane, (Heptadecafluoro- 1 , 1 ,2,2- tetrahydrodecyl)triethoxysilane (Fl 7), 1H,1H,2H,2H- Perfluorododecyltriethoxysilane, 1H,1H,2H,2H-Perfluorododecyltrimethoxysilane, 1H, 1H,2H,2H-Perfluorooctyltriethoxysilane, 1H, 1H,2H,2H-

Perfluorooctyltrimethoxysilane, 1H,1H,2H,2H-Perfluoropentyltriethoxysilane, 1H, 1H,2H,2H-Perfluoropentyltrimethoxysilane, 1H, 1H,2H,2H-

Perfluorotetradecyltriethoxysilane, or 1H,1H,2H,2H- Perfluorotetradecyltrimethoxysilane.

The fluorinated monomer can also be a monomer comprising a fluorinated polymer group. Said monomer comprising a fluorinated polymer group is preferably selected from fluorinated polysiloxanes, modified perfluoropolyethers.

The modified perfluoropolyethers are preferably selected from silane modified perfluoropolyethers, carboxyester modified perfluoropolyethers, such as acrylate modified perfluoropolyethers and methacrylate modified perfluoropolyethers, epoxybased perfluoropolyethers and mixtures thereof.

Such fluorinated polysiloxanes and modified perfluoropolyethers can be commercially available from Shin-Etsu Subelyn® fluorinated anti-smudge coating components of the KY-100 Series, such as KY-1900 and KY-1901, Shin-Etsu Subelyn® fluorinated anti-smudge additives of the KY-1200 Series, such as KY- 1271, or Daikin fluorinated anti-smudge coating components of the OPTOOL Series such as OPTOOL UD-509, OPTOOL UD-120 and OPTOOL DSX.

Other suitable fluorinated polysiloxanes are for example poly(methyl-3,3,3- trifluoropropyl)siloxane having a molecular weight in the range of from 1500 to 20000 g/mol, preferably from 2000 to 15000 g/mol.

The at least one fluorinated monomer is preferably present in the siloxane polymer in a weight amount of 0.1 to 45 wt%, preferably of 0.5 to 45 wt%, still more preferably of 1 to 40 wt%.

It is especially preferred that the monomers are selected from mixture of two or more of the group of 1,2-Bis(triethoxysilyl)ethane (BTESE), tetraethoxysilane (TEOS), phenylmethyl dimethoxysilane (PMDMS), 3-(Trimethoxysilyl)propylmethacrylate (MEMO), methyltrimethoxysilane (MTMS), vinyltrimethoxysilane (VTMS) and (3- Glycidoxypropyl)trimethoxysilane (GPTMS) and additionally a fluorinated monomer selected from KY-1900, KY-1901 and KY-1271. The third composition comprising a third siloxane polymer (D-l) is preferably formed by a method comprising the steps of

• Admixing the at least one silane monomer and the at least one fluorinated monomer, preferably as described above or below, in a first solvent to form a mixture;

• Optionally changing the first solvent to a second solvent;

The monomers can be admixed in the first solvent at any suitable temperature for solving the monomers. Usually, room temperature suffices.

Suitable catalysts are acidic catalysts, basic catalysts or other catalysts.

Acidic catalysts are preferably selected from nitric acid (HNO3), sulfuric acid (H2SO4), formic acid (HCOOH), hydrochloric acid (HC1), sulfonic acid, hydrogen fluoride (HF), acetic acid (CH3COOH), trifluoromethanesulfonic acid or -toluene sulfonic acid. Especially preferred acidic catalysts are nitric acid (HNO3), formic acid (HCOOH) and hydrochloric acid (HC1).

During the hydrolysis step the monomers are at least partially hydrolysed. Said at least partially hydrolysed monomers then are at least partially polymerized, preferably by condensation polymerization and crosslinked to form a siloxane polymer, which comprises side chains comprising one or more fluorinated carbon groups.

Said siloxane polymer usually has a relatively low molecular weight in range of about 500 to 2000 g/mol.

The first solvent can be changed to a second solvent in an optional further method step after the hydrolysis step. The optional solvent change is advantageous, since it assists the removal of water and alcohols formed during hydrolysis of the monomers. In addition, it improves the properties of the final siloxane polymer solution when used as coating layer(s) on the substrate. The second solvent is preferably selected from the group of propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), 1 -ethanol, 2-ethanol (IP A), acrylonitrile diacetone alcohol (DAA) or propylene glycol n-propyl ether (PnP).

Typically cross-linking is carried out at refluxing conditions of the solvent.

Optionally, resulting free Si-OH groups present in backbone of the siloxane polymer can be protected by an end-capping. For end capping, the free Si-OH groups are reacted with silanes such as methyldichlorofluorosilane (CEFSiCHs, methylfluorodimethoxysilane ((MeO^SiFCH?), 3 -chloropropyltrimethoxy silane (Cl(CH2)3Si(OMe)3), ethyltrimethoxysilane (ETMS), or trimethylchlorosilane (CISiMes) in presence of a catalyst such as tri ethylaluminium (TEA) or imidazole. The amount of catalyst varies from 1.5 to 2 wt% of total solid. The reaction time varies from 40 to 45 min. Other additives typically introduced into the first composition comprising the third siloxane polymer (D-l) include chemicals that can further modify the final surface properties of coated and cured film or improve wettability/adhesion properties of the coating layer (B) to the substrate layer (A) or the other coating layer (C) or improve coating drying and packing behavior during deposition and drying to reach good visual quality.

These additives can be surfactants, defoamers, antifouling agents, wetting agents etc. Examples of such additives include: BYK-301, BYK-306, BYK-307, BYK-308, BYK-333, BYK-051, BYK-036, BYK-028, BYK-057A, BYK-011, BYK-055, BYK-036, BYK-067A, BYK-088, BYK-302, BYK-310, BYK-322, BYK-323, BYK-331, BYK-333, BYK-341, BYK-345, BYK-348, BYK-377, BYK-378, BYK- 381, BYK-390, BYK-3700.

By adjusting the hydrolysis and condensation conditions it is possible to control the concentration/ content of the group capable of being deprotonated (e. g. an OH- group) and any residual leaving groups from the silane precursors (e.g. alkoxy groups) of the siloxane polymer composition and also to control the final molecular weight of the siloxane polymer. This greatly affects dissolution of the siloxane polymer material into the aqueous based developer solution. Furthermore, the molecular weight of the polymer also greatly effects on the dissolution properties of the siloxane polymer into developer solutions.

The solvent or solvent combination preferably comprises a fluorinated solvent such as methoxy-nonafluorobutane or l,l,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

Usually, a further amount of an initiator molecule compound is added to the siloxane composition after synthesis. The initiator, which can be optionally similar to the one added during polymerization, is used for creating a species that can initiate the polymerization of the “active” filnctional group in the UV curing step. Thus, in case of an epoxy group, cationic or anionic initiators can be used. In case of a group with double bonds as “active” functional group in the synthesized material, radical initiators can be employed. Also, thermal initiators (working according to the radical, cationic or anionic mechanism) can be used to facilitate the crosslinking of the “active” filnctional groups. The choice of a proper combination of the photoinitiators and sensitizers also depends on the used exposure source (wavelength). Furthermore, the selection of the used sensitizer depends on the selected initiator type.

In a third embodiment the third composition comprises a fourth siloxane polymer (D- 2).

Said fourth siloxane polymer (D-2) preferably does not comprise side chains comprising one or more fluorinated carbon groups.

The fourth siloxane polymer (D-2) comprises monomer units selected from at least one silane monomers.

It is preferred that the silane monomer units of the fourth siloxane polymer (D-2) and the preparation process for preparing the fourth siloxane polymer (D-2) are as described above for the third siloxane polymer (D-l), preferably with the exception that no fluorinated monomers as described above for the third siloxane polymer (D- 1) are present in the fourth siloxane polymer (D-2).

The following procedure applies for all embodiments of the third coating layer (D):

The third composition preferably comprises a fluoropolyether compound.

The fluoropolyether compound can be a single fluoropolyether compound or a mixture of two or more, such as 2-10, preferably 2-4 different fluoropoly ether compounds.

The fluoropoly ether compound usually has a molecular weight of 150 to 100,000 g/mol, more preferably 250 to 50,000 g/mol and most preferably 350 to 25,000 g/mol.

In the fluoropolyether compound not all hydrogen atoms may be replaced by fluorine. In case hydrogen atoms are present in the fluoropoly ether compound the molecular ratio fluorine/hydrogen is preferably at least 5, more preferably at least 10. The fluoropolyether compound can also be a perfluoropolyether compound.

The fluoropolyether group of the fluoropolyether compound may be a linear or branched group, preferably is a linear group.

The repeating units of the fluoropolyether group are preferably Ci to Ce fluorinated dialcohols, more preferably Ci to C4 fluorinated dialcohols and most preferably Ci to C3 fluorinated dialcohols.

Preferable monomers of the fluoropolyether group are perfluoro- 1,2-propylene glycol, perfluoro-l,3-propylene glycol, perfluoro- 1,2-ethylene glycol and difluoro- 1,1 -dihydroxy-methane, preferably perfluoro- 1,3 -propylene glycol, perfluoro- 1,2- ethylene glycol and difluoro-methanediol.

The latter monomer, difluoro- 1,1 -dihydroxy-methane, may be obtained by oxidizing poly(tetrafluoroethylene).

Preferred structures for a divalent perfluoropolyether group include -CF2O(CF2O)m(C2F4O)pCF2- wherein an average value for m and p is 0 to 150, with the proviso that m and p are not simultaneously zero,

-CF(CF3)O(CF(CF3)CF₂O)_PCF(CF3)-,

-CF2O(C2F₄O)_PCF2-, and

-(CF2)3O(C4F₈O)p(CF2)3- wherein an average value for p is 3 to 150.

Of these, particularly preferred structures are

-CF2O(CF2O)m(C2F₄O)pCF2 ,

-CF2O(C2F₄O)_PCF2-, and

-CF(CF3)(OCF2(CF3)CF)pO(CF2)mO(CF(CF3)CF₂O)pCF(CF3)-.

Preferred structures for a monovalent perfluoropolyether group, include

CF3CF2O(CF2O)m(C2F₄O)pCF2-,

CF₃CF2O(C2F₄O)pCF2-,

CF3CF2CF2O(CF(CF3)CF₂O)_PCF(CF3)-, or combinations thereof, where an average value for m and p is 0 to 150 and m and p are not independently 0.

The fluoropolyether compound can comprise functional groups such as carboxy groups, alkyl ester groups, carboxyester groups, epoxy groups, amino groups, silane groups or mixtures thereof. In one embodiment the fluoropolyether compound is a fluoropolyether silane, more preferably a fluoropolyether silane comprising hydrolysable groups (PFS).

The fluoropoly ether silane comprising hydrolysable groups (PFS) is preferably selected from compounds according to the following formula (IV)

R⁵-R^F-Q-Si(OR³)oR⁴ _P (IV) wherein R^F is a fluoropolyether group;

Q is a divalent linking group;

R³ is each independently selected from a Ci to Cio organyl or organoheteryl group;

R⁴ is each independently selected from a Ci to C20 organyl or organoheteryl group o is 1, 2 or 3 p is 0, 1 or 2 o+p is 3

R⁵ is H, C_XF2X+I with x being 1 to 10 or -Q-Si(OR³)_oR⁴ _P, with Q, R³, R⁴, o and p as defined above, whereby in each occurrence Q, R³, R⁴, o and p being present may be the same or different.

R³ is each independently selected from a Ci to Cio organyl or organoheteryl group. In case heteroatoms are present in the organyl group of R³ they are preferably selected from N, O, P, S or Si, more preferably selected from N and O.

Preferred groups OR³ are alkoxy, acyloxy and aryloxy groups.

The heteroatom of the organoheteryl group of R³ bound to the oxygen atom bound to M¹ is usually different from O. The heteroatom(s) present in the organoheteryl group of R³ are preferably selected from N, O, P or S, more preferably selected from N and O.

The total number of heteroatoms, if present, in R³ is usually not more than five, preferably not more than three.

Preferably R³ is a Ci to Cio organyl group containing not more than three heteroatoms, more preferably R³ is a Ci to Cio hydrocarbyl group, even more preferably a Ci to Cio linear, branched or cyclic alkyl group.

Preferably the total number of carbon atoms present in R³ according to any one of the above variants is 1 to 6, more preferably 1 to 4.

R⁴ is each independently selected from a Ci to C20 organyl or organoheteryl group

In case heteroatoms are present in the organyl group of R⁴ they are preferably selected from N, O, P, S or Si, more preferably selected from N and O.

The heteroatom of the organoheteryl group of R⁴ bound to Si is usually different from O.

The heteroatom(s) present in the organoheteryl group of R⁴ are preferably selected from N, O, P or S, more preferably selected from N and O.

The total number of heteroatoms, if present, in R⁴ is usually not more than eight, preferably not more than five and most preferably not more than three.

Preferably R⁴ is a Ci to C20 organyl group containing not more than three heteroatoms, more preferably R⁴ is a Ci to C20 hydrocarbyl group, even more preferably a Ci to C20 linear, branched or cyclic alkyl group. Preferably the total number of carbon atoms present in R⁴ according to any one of the above variants is 1 to 15, more preferably 1 to 10 and most preferably 1 to 6. o is preferably 1 to 3, more preferably 2 or 3 and most preferably 3 p is preferably 0 to 2, more preferably 0 or 1 and most preferably 0. o + p is 3.

The fluoropoly ether group R^F usually has a molecular weight of 150 to 10,000 g/mol, more preferably 250 to 5,000 g/mol and most preferably 350 to 2,500 g/mol.

In the fluoropolyether group R^F not all hydrogen atoms may be replaced by fluorine. In case hydrogen atoms are present in the fluoropolyether group R^F the molecular ratio fluorine/hydrogen is preferably at least 5, more preferably at least 10. More preferably, the fluoropolyether group R^F is a perfluoropoly ether group.

The fluoropolyether group R^F may be a linear or branched group, preferably is a linear group.

The repeating units of the fluoropolyether group R^F are preferably Ci to Ce fluorinated dialcohols, more preferably Ci to C4 fluorinated dialcohols and most preferably Ci to C3 fluorinated dialcohols.

Preferable monomers of the fluoropolyether group R^F are perfluoro- 1,2-propylene glycol, perfluoro-l,3-propylene glycol, perfluoro- 1,2-ethylene glycol and difluoro- 1,1 -dihydroxy-methane, preferably perfluoro- 1,3 -propylene glycol, perfluoro- 1,2- ethylene glycol and difluoro-methanediol.

The latter monomer, difluoro- 1,1 -dihydroxy-methane, may be obtained by oxidizing poly(tetrafluoroethylene). Preferred structures for a divalent perfluoropolyether group include

-CF2O(CF2O)m(C2F₄O)pCF2- wherein an average value for m and p is 0 to 50, with the proviso that m and p are not simultaneously zero,

-CF(CF3)O(CF(CF3)CF₂O)_PCF(CF3)-,

-CF2O(C2F₄O)_PCF2-, and

-(CF2)3O(C₄F₈O)p(CF2)3- wherein an average value for p is 3 to 50.

Of these, particularly preferred structures are

-CF₂O(CF2O)m(C2F₄O)_PCF2 ,

-CF₂O(C2F₄O)_PCF2-, and

-CF(CF3)(OCF2(CF3)CF)pO(CF2)mO(CF(CF3)CF₂O)pCF(CF3)-.

Preferred structures for a monovalent perfluoropolyether group, include

CF3CF2O(CF₂O)m(C2F₄O)pCF2-,

CF₃CF₂O(C2F₄O)pCF2-,

CF3CF2CF2O(CF(CF3)CF₂O)_PCF(CF3)-, or combinations thereof, where an average value for m and p is 0 to 50 and m and p are not independently 0.

Especially preferable are fluoropolyether groups R^F are selected from

- CF2O- [C2F₄O]_m- [CF2O]_n- with 1 < n < 8 and 3 < m < 10

R-[C3FeO]n- with n = 2 to 10 and R being a linear or branched, preferably linear, perfluorinated C2 or C3-alcohol, preferably C3-alcohol;

The divalent linking group Q links the perfluorpolyether with the silicon-containing group. Q is usually having a molecular weight of not more than 500 g/mol, more preferably not more than 250 g/mol and most preferably not more than 150 g/mol. Examples for divalent linking groups are amide-containing groups and alkylene groups.

Fluoropolyether compounds can be commercially available without public knowledge of their exact chemical structure.

Suitable commercially available fluoropolyether compounds are, for example Fluorolink S10 (CAS no. 223557-70-8, Solvay), Optool™ DSX (Daikin Industries), Shin-Etsu Subelyn™ KY-1900 and KY-1901 (Shin-Etsu Chemical), Dow Corning® 2634 (CAS no. 870998-78-0) and SC-011 and SC-019 (Shin-Etsu Chemical).

The third composition is deposited onto the onto at least one surface of the second coating layer (C) to form a third coating layer (D) in adherent contact with the at least one surface of the second coating layer (C).

The deposited third composition forms the third coating layer (D) on the surface of the second coating layer (C). Typically, after deposition, or during the deposition step, the solvent is evaporated and the third coating layer (D) is dried, preferably by thermal drying or optionally by vacuum and/or thermal drying combined. This step is also referred to as pre-curing.

In a second, subsequent step the third coating layer (D) is cured to final hardness by using thermal curing at elevated temperature or UV exposure followed by thermal curing at elevated temperature. In one embodiment, the pre-curing and the final curing steps are combined by carrying out heating by using an increasing heating gradient. In addition to the thermal cure only process, the curing can be performed in three steps, the process comprising thermal pre-cure and UV-cure followed by final thermal cure. It is also possible to apply a two step curing process where thermal pre-cure is followed by UV-cure. In such a case no final thermal cure is preferably applied after UV-cure).

Thus, in one embodiment the method comprises the steps of

- pre-curing or drying the third coating layer (D) deposited on the second coating layer (C); optionally exposing the thus obtained third coating layer (D); optionally developing the thus obtained third coating layer (D); and curing the third coating layer (D).

Exemplary epoxy -functional group containing monomers include (3- glycidoxypropyl)trimethoxysilane, l-(2-(Trimethoxysilyl)ethyl)cyclohexane-3,4- epoxide, (3-glycidoxypropyl)triethoxysilane, (3- glycidoxypropyl)tripropoxysilane, 3-glycidoxypropyltri(2-methoxyethoxy)silane, 2,3-epoxypropyltriethoxysilane, 3,4- epoxybutyltriethoxysilane, 4,5- epoxypentyltriethoxysilane, 5,6- epoxyhexyltriethoxysilane, 5,6- epoxyhexyltrimethoxysilane, 2-(3,4- epoxycy cl ohexyl)ethyltri ethoxy silane, 2-(3,4- epoxy cy cl ohexyl)ethyltrimethoxy silane, 4-(trimethoxy silyl)butane- 1 ,2-epoxide. Further examples of functionalized compounds are acrylate and metacrylate compounds, such as tetraethylene glycol diacrylate, trimethylo Ipropane triacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate and combinations thereof. Such compounds can be used as part of the silane compositions.

According to a particular embodiment the method further includes curing the third composition.

The thickness of the third coating layer (D) on the second coating layer (C) (i.e. the film thickness) may range from 10 nm to 10 pm, preferably of 15 nm to 8 pm, more preferably 20 nm to 5 pm.

In one embodiment the third coating layer (D) preferably is an easy-to-clean coating layer comprising a siloxane polymer as described in WO 2016/146895 or WO 2020/099290

In another embodiment the third coating layer (D) preferably is a flexible hard coat layer comprising a third siloxane polymer (D-l) which comprises side chains comprising one or more fluorinated carbon groups.

In yet another embodiment the third coating layer (D) preferably is a flexible hard coat layer comprising a fourth siloxane polymer (D-2).

It is preferred that the hardness of the third coating layer (D) is greater than 3H, over 4H, over 5H, over 6H or even over 7H as determined by ASTM D3363-00, Elcometer tester.

Preferably the third coating layer (D) has an adhesion of 4B-5B, as tested by ASTM D3359-09, Cross-Hatch tester. Further, the third coating layer (D) preferably has a scratch resistance as evidenced by no visual scratches on a Taber linear abrasion test (Using Linear Abraser from Taber Industries) carried out at up to 2000 linear cycles with BonStar steel wool #0000, at 500g weight, 2x2 cm head size, 2.0-inch stroke length, 60 cycles/min.

Layered structure

The layered structure according to the present invention in one embodiment comprises the substrate layer (A), the first coating layer (B) and the second coating layer (C). In said embodiment the second coating layer (C) is the outermost layer of the layered structure and sandwiches together with the substrate layer (A) the first coating layer (B). This means that preferably no further coatings or coating layers are applied on the at least one surface of the substrate layer (A).

In another embodiment the layered structure additionally comprises the third coating layer (D). In said embodiment the layered structure according to the present invention comprises the substrate layer (A), the first coating layer (B), the second coating layer (C) and the third coating layer (D). In said embodiment the third coating layer (D) is the outermost layer of the layered structure and sandwiches together with the substrate layer (A) the second coating layer (C) and the first coating layer (B), with the first coating layer (B) preferably being the innermost layer in adherent contact with the surface of the substrate layer. This means that preferably no further coatings or coating layers are applied on the at least one surface of the substrate layer (A).

The layered structure shows a good balance of properties of adhesion of the different layers to each other, high scratch resistance and low reflectance.

The layered structure preferably shows an adhesion of the first coating layer (B) to the substrate layer (A) of 4-5B. Further the layered structure preferably shows an adhesion of the second coating layer (C) to the first coating layer (B) of 3-5B.

Further, the layered structure preferably shows an initial water contact angle of at least 75°, preferably at least 90°.

Still further the layered structure preferably shows a scratch resistance corresponding to a visual quality of 0 to 2 on a Taber linear abrasion test (Using Linear Abraser from Taber Industries) carried out at up to 500 linear cycles with BonStar steel wool #0000, at 500g weight, 2x2 cm head size, 2.0-inch stroke length, 60 cycles/min.

Further, the layered structure preferably shows a contact angle of at least 70° on a Taber linear abrasion test (Using Linear Abraser from Taber Industries) carried out at up to 500 linear cycles with BonStar steel wool #0000, at 500g weight, 2x2 cm head size, 2.0-inch stroke length, 60 cycles/min.

Still further the layered structure preferably shows a reflectance at 550 nm of not more than 4.0%, preferably not more than 3.5%, when measured on a coated PMMA substrate.

Further, the layered structure preferably shows a transmittance at 550 nm of at least 93.0%, preferably at least 93.5%, when measured on a coated PMMA substrate.

The layered structure according to the present invention is suitable for flexible electronics applications, including displays, optical lens, transparent boards, and automotive industries especially as a lightweight alternative to glass.

The present invention is further characterized by the following non-limiting examples: Examples

1. Determination methods

Molecular weight: the polymers were characterized by gel permeation chromatography. The chromatographic system consisted of a GPC apparatus equipped with an isocratic HPLC pump and a refractive index detector. The polysiloxanes (0,20 g; 50% solid content) were dissolved in THF (HPLC-grade; 2,30 g). The analyte injection volume was 100 pL, the flow was 0,70 mL / min, and the column temperature was set to 40 °C. Four polysterene exclusion-based columns were used. The mobile phase was THF (HPLC grade). Number-average molecular weight (Mn) and the weight-average molecular weight (Mw) of the polymers were determined using internal standards, e.g. two series of polystyrenes (Serie A: 5 polystyrenes with r = 120.000 g/mol, 42.400 g/mol, 10.700 g/mol, 2.640 g/mol, 474 g/mol and Serie B: 4 polymers with Mr = 193.000 g/mol, 16.700 g/mol, 6.540 g/mol, 890 g/mol).

Solid contents: The solid content of the polymers was determined using a Mettler Toledo HB43 instrument. The sample was weighted on aluminum dish / cup and the measurement was performed using about 1 g of material.

Viscosity: the used tool was a Grabner Instruments Viscometer MINIVIS-II. The used method was “falling ball viscosity measurement”. Samples were measured at T = 20 C by using a stell ball with3.175 mm diameter.

Film thickness and refractive index (RI): the film thickness and refractive index were measured using Ellipsometer UVISEL-VASE Horiba Jobin-Yvon. Measurements are performed using Gorilla Glass 4 or silicon wafer (diameter: 150 mm, Type/Dopant: P/Bor, Orientation: <l-0-0>, Resistivity: 1-30 Q.cm, thickness: 675 +/- 25 pm, TTV: < 5 pm, particle: < 20 @ 0,2 pm, Front surface: polished; back surface: etched; Flat 1 SEMI standard) or other suitable substrates. The material fil could be prepared on pre-treated (plasma) glass substrate ny using a spray tool (typical sprat process: scan speed: 300 mm/s; pitch: 50 mm; gap: 100 mm; flow rate: 5-6 ml/min; atomization air pressure: 5 kg I cm²), followed by thermal cure example at T = 150 °C for 60 min.

Transmission (T%) and reflection (R%): A Konica Minolta spectrophotometer CM-3700A (Specta Magic NX software) was used to measure transmittance and reflectance.

Color and Haze measurement: L*(D 65), a*(D 65) and b*(D 65) and Haze were determined by using A Konica Minolta spectrophotometer CM-3700A (Specta Magic NX software)

Pencil hardness (PEHA): the pencil hardness was determined according to ASTM standard D3363-00 using a Elcometer pencil hardness tester.

Water contact angle (WCA): the static contact angle measurement was performed by optical tensiometer using distilled water, 4 pL droplet size, three measurement points average was recorded as the measurement result value and Young-Laplace equation was used as the numerical method to describe the contour of the drop (tool: attention theta optical tensiometer).

Abrasion:

For the 2^nd layer and 3^rd layer structures, the abrasion testing was carried out using Bon star steel wool #0000, 500 g load, 2 x 2 cm head, 2-inch stroke, 60 cycles / minute, 500 cycles using taber linear abraser 5750.

Visual quality (VQ): the visual inspection can be observed with bear eyes, under microscope using a green or red-light quality lamp inspection. The visual quality can be scored between 0 (best) to 3 (worse).

Adhesion: the adhesion was determined according to ASTM standard D3359-D9 using a Elcometer cross-hatch tester and Elcometer tape test. 2. List of components used in the examples: a) Silane Monomers:

GPTMS = (3 -Glycidoxypropyl)trimethoxy silane, Sigma-Aldrich

PMDMS = phenyl methyl dimethoxy silane, Sigma-Aldrich

MEMO = 3 -(Trimethoxy silyl)propylmethacrylate, ABCR

BTESE = 1,2-Bis(triethoxysilyl)ethane, Momentive Performance Materials

MTMS = methyl trimethoxysilane, ABCR

TEOS = tetraethoxysilane, Ultra Pure Solutions Inc.

DPDMS = diphenyl dimethoxysilane, Sigma-Aldrich

PTMS = phenyl trimethoxysilane, Sigma-Aldrich

Me-GPTMS = (3-Glycidoxypropyl)methyldimethoxysilane, ABCR trimethoxy (octyl) silane, Sigma-Aldrich

4-trifluoromethy 1 -tetrafluorophenyltri ethoxy sil ane, AB CR

F13 = lH,lH,2H,2H-perfluorooctyltrimethoxysilane, Sigma-Aldrich 1H, lH,2H,2H-perfluorooctyltriethoxysilane, Sigma-Aldrich

F17 = lH,lH,2H,2H-perfluorodecyltrimethoxysilane, VWR labscan 1H, lH,2H,2H-perfluorododecyltriethoxysilane, Sigma-Aldrich (heptadecafluoro- 1 , 1 , 2, 2-tetrahydrodecyl)tri ethoxy silane, Sigma-Aldrich N onafluorohexy Itri ethoxy sil ane, Sigma- Al dri ch Bis[(2,2,3,3,4,4-hexafluorobutyl)propanoic ester]-3-aminopropyltrimethoxysilane It was prepared by reaction between amino propyl trimethoxysilane (APTMES, Sigma- Aldrich) and 2,2,3,3,4,4-hexafluorobutyl acrylate (OFPA, Sigma-Aldrich). The preparation is described below:

In a 100 mL 3 necks round bottom flask, APTMES (10 g) was cooled to T = 0 °C. OFPA (33.51 g) is added dropwise at T = 0 °C. The reaction mixture was allowed to reach room temperature and then was stirred at T = 60 °C for 18 h. The reaction was monitored by TLC (eluent: cyclohexane / EtOAc = 3 / 1). Excess of OFPA was removed under low pressure. b) Polysiloxanes poly(methyl-3,3,3-trifluoropropylsiloxane), Mw = 2500 D, ABCR poly(methyl-3,3,3-trifluoropropylsiloxane), Mw 14000 D, ABCR TEOS-based polymer /100%-TEOS polymer:

In a 500 mL round bottom flask, TEOS (43.46 g) was mixed with acetone (136.08 g). HNO3 (0.1M; 29.98 g) was added dropwise over 10-15 min. The reaction mixture was refluxed for 2h. After cooling to room temperature, PGME (115 g) was added. Solvent exchange procedure from EtOH / H2O / acetone to PGME was performed under vacuum. The final solid content of the mixture was adjusted to 10% by addition of more PGME. c) Solvents:

DAA = diacetone alcohol, Merck

EtOH = ethanol, Altia VWR

PGME = l-methoxy-2-propanol, Ultra Pure Solutions Inc.

MeOH = methanol, Merck

IPA = 2-propanol, Merck

PGMEA = propylene glycol monoethyl ether acetate, Ultra Pure Solutions Inc.

MTBE = methyl tert-butyl ether, Sigma-Aldrich

EG = ethylene glycol, Sigma-Aldrich

DiPG = dipropylene glycol, Sigma- Aldrich

Acetone, Brenntag d) Catalysts:

HNO3 = nitric acid, Merck

HC1 = hydrochloric acid, Merck

Formic acid, Sigma-Aldrich

TEA = triethylamine, Sigma-Aldrich e) Fluorinated additives KY 1900 = perfluoropoly ether with reactive silyl group, Shin-Etsu

KY 1901 = perfluoropoly ether with reactive silyl group, Shin-Etsu

KY 1271 = fluorinated anti-smudge additive, Shin-Etsu

DSX = OPTOOL DSX E (fluoropoly ether silane), Daikin

SC 019 = fluoropoly ether compound, Shin-Etsu

SC 011 = fluoropoly ether compound, Shin-Etsu

Novec 7100 = mixture of isomers of methoxy -nonafluorobutane, 3M

AE 3000 = l,l,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, Daikin f) Other chemicals:

AIBN = azobisisobutyronitrile, Sigma Aldrich

UVI Speed Cure 976 = (sulfanediyldibenzene-4,l-diyl)bis(diphenylsulfonium), Lamb son

BYK 333 = polyether-modified polydimethyl siloxane, BYK

BYK 345 = polyether-modified siloxane, BYK

BYK 370 = polyester-modified, hydroxy-functional polydimethylsiloxane, BYK

BYK 067A = anti-foaming agents, BYK

M262 = tri cyclodecane dimethanol diacrylate, Miwon

M2372 = Tris(2-hydroxyethylisocyanurate) Di / Triacrylate, Miwon

M270 = tetraethylene glycol diacrylate, Miwon

CISiMes = chlorotrimethylsilane, Sigma Aldrich

3. Preparation examples a) Preparation Examples for first coating layer (B)

The compositions for the first coating layer are adapted to the substrate especially in regard of the curing and baking conditions. Thereby, composition 30 is especially adapted as first coating layer for PMMA substrates and composition 31 is especially adapted as first coating layer for PET or CPI.

Composition B-l In a 2L round bottom flask, GPTMS (900 g; 3,804 mol), PMDMS (99,06 g; 0,27 mol) and MEMO (301,32 g; 0,54 mol) are mixed. HNO3 (0,lM; 212,4 g) is added dropwise over 15 min. The reaction mixture is then stirred at room temperature overnight. Diacetone alcohol (DAA; 600 g) is then added and solvent exchange from MeOH / EtOH / H2O to DAA is performed under low pressure. The final solid content is adjusted to 50 % by addition of extra DAA. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material), M270 (15% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-2

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and Bis[(2,2,3,3,4,4-hexafluorobutyl)propanoic ester]-3-aminopropyltrimethoxysilane (2,76 g; 0,00043 mol) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added.

Composition B-3

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and 4-trifluorom ethyltetrafluorophenyltriethoxysilane (0,05 g; 0,00131 mol) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added. Composition B-4

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and lH,lH,2H,2H-perfluorooctyltriethoxysilane (2,05 g; 0,0040 mol) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-5

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and poly(methyl-3,3,3-trifluoropropylsiloxane) (2 g; Mw = 2500 D) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-6

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and poly(methyl-3,3,3-trifluoropropylsiloxane) (2,3 g; Mw = 14000 D) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-7

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and lH,lH,2H,2H-perfluorododecyltriethoxysilane (0,73 g) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-8

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and (heptadecafluoro- 1,1, 2,2- tetrahydrodecyl)triethoxysilane (0,5 g) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-9

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) and nonafluorohexyltriethoxysilane (2 g) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added.

Composition B-10

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. Additional PGME is added to have a polymer with solid content of 41.85%. The product is then formulated before performance evaluation as follow: the material was further diluted to 30% solid content with IPA and the additives Speed Cure 976 (1.2 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-ll

In a IL round bottom flask, MTMS (78,46 g; 0,576 mol), TEOS (20 g; 0,096 mol), GPTMS (22,69 g; 0,096 mol) were mixed in EtOH (121,15 g). Formic acid (0.1M; 86,40 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was refluxed for 2h. Then the reaction mixture was cooled to room temperature and PGME (100 g) was added. Solvent exchange procedure from EtOH to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-12

In a IL round bottom flask, BTESE (63,83 g; 0,18 mol), MEMO (14,90 g; 0,06 mol), GPTMS (226,9 g; 0,96 mol) were mixed in acetone (229,21 g). HNO3 (0.1M; 74,59 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a 2L round bottom flask and PGME (150 g) was added. Solvent exchange procedure from acetone to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added.

Composition B-13

In a IL round bottom flask, BTESE (63,83 g; 0,18 mol), MEMO (14,90 g; 0,06 mol), GPTMS (218,38 g; 0,924 mol), F17 (20,46 g; 0,036 mol) were mixed in acetone (238,18 g). HNO3 (0.1M; 74,59 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a 2L round bottom flask and PGME (150 g) was added. Solvent exchange procedure from acetone to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-14

In a IL round bottom flask, BTESE (63,83 g; 0,18 mol), MEMO (14,90 g; 0,06 mol), GPTMS (218,38 g; 0,924 mol), F13 (18,36 g; 0,036 mol) were mixed in acetone (238,60 g). HNO3 (0.1M; 74,59 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a 2L round bottom flask and PGME (150 g) was added. Solvent exchange procedure from acetone to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-15

In a IL round bottom flask, BTESE (14,51 g; 0,0409 mol), MEMO (20,33 g; 0,0818 mol), GPTMS (62,87 g; 0,266 mol), DPDMS (5,06 g; 0,020 mol) were mixed in acetone (77,03 g). HNO3 (0.1M; 23,96 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new IL round bottom flask and PGME (60 g) was added. Solvent exchange procedure from acetone to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-16

In a IL round bottom flask, PTMS (10,00 g; 0,050 mol), MEMO (18,79 g; 0,076 mol), GPTMS (77,47 g; 0,327 mol), BTESE (17,88 g; 0,050 mol) were mixed in acetone (93,11 g). HNO3 (0.1M; 29,98 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new IL round bottom flask and PGME (75 g) was added. Solvent exchange procedure from acetone to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-17

In a IL round bottom flask, BTESE (31,91 g; 0,18 mol), MEMO (22,35 g; 0,18 mol), GPTMS (99,26 g; 0,84 mol) were mixed in acetone (15 g). HNO3 (0.1M; 37,26 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new IL round bottom flask and PGME (92 g) was added. Solvent exchange procedure from acetone to PGME was performed under low pressure. A part of the previous solution (50 g, 50% solid content in PGME) was mixed with AIBN (0.1 g) and the reaction mixture was stirred at T = 105 C for 5 min. After cooling to room temperature, the final product was ready for processing. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added.

Composition B-18

In a IL round bottom flask, BTESE (25,00 g; 0,070 mol), Me-GPTMS (36,25 g; 0,164 mol), GPTMS (38,88; 0,164 mol), MEMO (17,51; 0,070 mol) are mixed in acetone (88,23 g). HNO3 (0.1M; 26,25 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new IL round bottom flask and PGME (70,58 g) was added. Solvent exchange procedure from acetone to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-19

In a IL round bottom flask, MEMO (35,02 g; 0,141 mol), GPTMS (86,85 g; 0,366 mol), BTESE (20,00 g; 0,056 mol) were mixed in IPA (106,25 g). HNO3 (0.1M; 33,53 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new IL round bottom flask and IPA (75 g) was added. Solvent exchange procedure from IPA to IPA was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-20

In a 500 mL round bottom flask, MTMS (90,00 g; 0,660 mol), GPTMS (22,31 g; 0,094 mol) were mixed in EtOH (112,31 g). Formic acid (0.1M; 122,32 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new 500 mL round bottom flask and PGMEA (100 g) was added. Solvent exchange procedure from EtOH to PGMEA was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added.

Composition B-21

In a 250 mL round bottom flask, TEOS (14,00 g; 0,048 mol), MTMS (1,00 g; 0,0074 mol), F17 (7,34 g; 0,0129 mol), GPTMS (1,31 g; 0,006 mol) were mixed. HC1 (0.1M; 4,88 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new 250 mL round bottom flask and IPA (14,3 g) was added. Solvent exchange procedure from EtOH/MeOH/FLO to IPA was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-22

In a 250 mL round bottom flask, TEOS (14,00 g; 0,067 mol), MTMS (1,91 g; 0,014 mol), F17 (11,4 g; 0,0196 mol), GPTMS (2,65 g; 0,0112 mol) were mixed. Formic acid (0.1M; 7,26 g) was added dropwise over 15 min. After completion of the addition, the reaction mixture was stirred at room temperature overnight. Then the reaction mixture was transferred to a new 250 mL round bottom flask and IPA (18,48 g) was added. Solvent exchange procedure from EtOH/MeOH/ELO to IPA was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-23

In a IL round bottom flask, BTESE (31,91 g; 0,18 mol), GPTMS (99,26 g; 0,84 mol), MEMO (22,25 g; 0,18 mol) were mixed in acetone (115 g). HNO3 (0.1M; 36,26 g) was added dropwise over 15 min and the reaction mixture was stirred at room temperature overnight. PGME (92 g) was added, and solvent exchange procedure from acetone to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added.

Composition B-24

In a IL round bottom flask, MTMS (58,02 g; 0,42 mol), TEOS (19,57 g; 0,090 mol), MEMO (7,00 g; 0,028 mol), GPTMS (18,50 g; 0,078 mol) were mixed in EtOH (103,09 g). Formic acid (0.1M; 71,04 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (90 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-25

In a IL round bottom flask, MTMS (98,73 g; 0.724 mol), MEMO (15,00 g; 0,060 mol), TEOS (12,58 g; 0,060 mol), GPTMS (28,55 g; 0,12 mol) were mixed in EtOH (154,86 g). Formic acid (0.1M; 106,54 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. AIBN (1.11 g) was then added at room temperature and the reaction mixture was stirred at T = 95 C for 5 min. After cooling to room temperature, the final product was ready for processing. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added. -n -

Composition B-27

In a IL round bottom flask, GPTMS (450 g; 1,902 mol), MEMO (150,00 g; 0,54 mol), PMDMS (49,53 g; 0,27 mol) were mixed. HNO3 (0.1M; 106,2 g) was added dropwise and the reaction mixture was stirred at room temperature overnight. DAA (300 g) was added and solvent exchange procedure from MeOH/ELO to DAA was performed under low pressure. The solid content of the was remains 50% for final formulation. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-28

In a 500ml round bottom flask, MTMS (40 g; 0,2936 mol), TEOS (61,17 g; 0,29364 mol), EtOH (101.17 g; 2,2075 mol) were mixed. Formic acid (0.1M; 74 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The solid content was adjusted to 41.85% with addition of PGME. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067 A (1% of solid material) were added.

Composition B-29

In a 500 ml round bottom flask, MTMS (40 g; 0,2936 mol), TEOS (61,17 g; 0,29364 mol), EtOH (101.17 g; 2,2075 mol) were mixed. Formic acid (0.1M; 33 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (33 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. Now trimethoxy (octyl) silane (5g, 0,0213 mol) was added in the solution. Formic acid (0. IM; 3,46 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material) and BYK 067A (1% of solid material) were added.

Composition B-30

In a IL round bottom flask, GPTMS (900 g), MEMO (301,32 g), PMDMS (99,09 g) were mixed. HNO3 (0.1M; 212.4 g) was added slowly over 10-15 min. Then, the reaction mixture was stirred at RT overnight. DAA (600 g) was added and solvent exchange from MeOH/ELO to DAA was performed under vacuum. The final solid content of the reaction mixture was adjusted to 50% by addition of DAA. The product is then formulated before performance evaluation as follow: the material was further diluted to 33% solid content with IPA and the additives Speed Cure 976 (1.5 % of solid material), BYK 333 (1% of solid material), M270 (15% of solid content) and BYK 067A (1% of solid material) were added.

Composition B-31

In a 500 mL round bottom flask, BTESE (21,15 g; 0,06 mol), GPTMS (91 g; 0,3875 mol), MEMO (37 g; 0,149 mol) are mixed in acetone (112,4 g). HNO3 (0,lM; 35,47 g) is added dropwise over 15 min and the reaction mixture is stirred at room temperature overnight. PGME (90 g) is added and solvent exchange procedure from acetone to PGME was performed. Additional PGME is added to have a polymer with solid content of 41.85%. The product is then formulated before performance evaluation as follow: the material was further diluted to 30% solid content with IPA and the additives Speed Cure 976 (1.2 % of solid material), BYK 370 (1% of solid material) and BYK 067A (1% of solid material) were added. b) Preparation Examples for the second coating layer (C) Composition C-l

In a 500ml round bottom flask, MTMS (10,5 g; 0,0771 mol), TEOS (30,0 g; 0,1440 mol), EtOH (163 g; 3,52 mol) were mixed. HC1 (1,0 M; 33,9 g) was added dropwise and the reaction mixture was stirred at room temperature for 3,5 h. The organic phase was washed 5 times with a mixture H2O/MTBE (0,9: 1,05). EtOH (183.43 g) was added and the solvent exchange procedure to EtOH was performed under vacuum. The solid content of the reaction mixture was adjusted to 4% by addition of EtOH (25.44 g). TEA (0,130 g) was then added at RT and the reaction mixture was stirred T = 70 C for 45 min. After cooling to RT, the organic phase was washed 5 times with a mixture H2O/MTBE (0,9: 1,05). The organic phase was collected, EtOH (89.04 g) and PGME (190 g) was added and solvent exchange to PGME was performed under vacuum. CISiMei (0,041 g) was added at RT and the reaction mixture was stirred at T = 105 C for 30 min. Part of the polymer (11.47 g as 5.23% solid content in PGME) was mixed with KY 1901 (0.4 % in Novec 7100; 6,25 g), Novec 7100 (17.85 g), IPA (12.83 g), EG (1.24 g) and TEOS-based polymer (0.36 g as 10% solid content in PGME).

Composition C-2

In a 10L round bottom flask, HNO3 (3M, 804 g) and IPA (3771 g) are mixed, followed by TEOS (570 g, 2,736 mol) and MTMS (373 g, 2,7382 mol) over 20 min using a separation funnel. After addition, the reaction mixture was stirred at RT for 3,5h.

Washing step was done with a mixture of H2O/MTBE (0,9: 1,05) several times for 4 days. Part of the polymer (11.47 g as 5.23% solid content in PGMEA) was mixed with KY 1901 (0.4 % in Novec 7100; 6,25 g), Novec 7100 (17.85 g), IPA (12.83 g), EG (1.24 g) and TEOS-based polymer (0.36 g as 10% solid content in PGME). Composition C-3

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (11.47 g as 5.23% solid content in PGMEA) was mixed with KY 1901 (0.4 % in Novec 7100; 6,25 g), Novec 7100 (17.85 g), IPA (12.83 g), EG (1.24 g) and TEOS-based polymer (0.36 g as 10% solid content in PGME).

Composition C-4

In a 250 L reactor, TEOS (43,436 kg) was mixed with acetone (136 kg). HNO3 (0.01 M; 2,978 kg) was slowly added to the reaction mixture at RT over 10-20 min. Then, the reaction mixture was refluxed for Ih. After cooling to RT, PGME (115 kg) was added and solvent exchange from acetone / H2O / EtOH to PGME was performed under vacuum. The solid content of the mixture was adjusted to 10% by addition of PGME. Part of the polymer (6 g as 10% solid content in PGME) was mixed with DSX (0.4 % in AE 3000; 18,75 g), AE 3000 (56,125 g), PGME (65,68 g) and DiPG (3,72 g).

Composition C-5

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (30.59 g as 5.23% solid content in PGMEA) was mixed with IPA (69.40 g), and BYK 333 (0.064 g).

Composition C-6

In a 250 L reactor, HN0₃ (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (5.73 g as 5.23% solid content in PGMEA) was mixed with Novec 7100 (7.19 g), IPA (18.29 g), EG (1.24 g), TEOS-based polymer (as 10% solid content in PGME; 0.09 g) and BYK 333 (0.018 g).

Composition C-7

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (9.56 g as 5.23% solid content in PGMEA) was mixed with Novec 7100 (6.93 g), IPA (14.65 g), EG (1.24 g), TEOS-based polymer (as 10% solid content in PGME; 9.56 g) and BYK 333 (0.014 g).

Composition C-8

In a 250 L reactor, HN0₃ (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (4.78 g as 5.23% solid content in PGMEA) was mixed with Novec 7100 (3.35 g), IPA (3.09 g), PGME (6.11 g), TEOS-based polymer (as 10% solid content in PGME; 1.00 g) and BYK 333 (0.010 g).

Composition C-9

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IP A (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (11.47 g as 5.23% solid content in PGMEA) was mixed with IPA (69.40 g), and BYK 333 (0.064 g).

Composition C-10

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (22.94 g as 5.23% solid content in PGMEA) was mixed with IPA (69.40 g), and BYK 333 (0.064 g).

Composition C-ll

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IP A (70 kg) was added and solvent exchange from H2O / IP A / EtOH / MeOH to IP A was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IP A (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (19.12 g as 5.23% solid content in PGMEA) was mixed with IPA (69.40 g), and BYK 333 (0.064 g).

Composition C-12

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (17.20 g as 5.23% solid content in PGMEA) was mixed with IPA (69.40 g), and BYK 333 (0.064 g).

Composition C-13 In a 250 L reactor, HN0₃ (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (5.73 g as 5.23% solid content in PGMEA) was mixed with EG (0.62 g), IPA (3,41 g), Novec 7100 (8.78 g), KY 1901 (0.4% in Novec 7100; 3.12 g) and 100%-TEOS polymer (as 10% solid content in PGME, 3g).

Composition C-14

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (428.3 g as 5.23% solid content in PGMEA) was mixed with PGME (732.98 g), EtOH (345.8 g), M262 (4.29 g), M2372 (4.29 g) and BYK 345 (0.896 g).

Composition C-15

In a 250 L reactor, HN0₃ (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (7.17 g as 5.23% solid content in PGMEA) was mixed with KY1901 (0.4% in Novec 7100; 3.12 g), Novec 7100 (7.62 g), IPA (4.67 g), EG (0.62 g) and TEOS-based polymer (as 10% solid content in PGME; 1.12 g).

Composition C-16

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (7.17 g as 5.23% solid content in PGMEA) was mixed with SC 011 (0.4% in Novec 7100; 3.12 g), Novec 7100 (7.62 g), IPA (4.67 g), EG (0.62 g) and TEOS-based polymer (as 10% solid content in PGME; 1.12 g).

Composition C-17

In a 250 L reactor, HN0₃ (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (7.17 g as 5.23% solid content in PGMEA) was mixed with SC 019 (0.4% in Novec 7100; 3.12 g), Novec 7100 (7.62 g), IPA (4.67 g), EG (0.62 g) and TEOS-based polymer (as 10% solid content in PGME; 1.12 g).

Composition C-18

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IP A (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (7.17 g as 5.23% solid content in PGMEA) was mixed with KY1901 (0.4% in Novec 7100; 6.24 g), Novec 7100 (7.62 g), IPA (4.67 g), EG (0.62 g) and TEOS-based polymer (as 10% solid content in PGME; 1.12 g).

Composition C-19

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (7.17 g as 5.23% solid content in PGMEA) was mixed with SC 011 (0.4% in Novec 7100; 3.12 g), Novec 7100 (5.26 g), IPA (4.67 g), EG (0.62 g) and TEOS-based polymer (as 10% solid content in PGME; 3.75 g).

Composition C-20 In a 250 L reactor, HN0₃ (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (7.17 g as 5.23% solid content in PGMEA) was mixed with SC 019 (0.4% in Novec 7100; 3.12 g), Novec 7100 (5.26 g), IPA (4.67 g), EG (0.62 g) and TEOS-based polymer (as 10% solid content in PGME; 3.75 g).

Composition C-21

In a 250 L reactor, HNO3 (3M; 14,445 kg) and IPA (54,72 kg) are mixed. MTMS (5,368 kg) and TEOS (8,196 kg) are added. The reaction mixture is stirred at RT for 3,5h. The organic phase was washed five times with a mixture H2O / MTBE (1 :1). IPA (70 kg) was added and solvent exchange from H2O / IPA / EtOH / MeOH to IPA was performed under low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of IPA (31 kg). TEA (0,3417 kg) was added at RT and the reaction mixture was further stirred at T = 60 C for 36 min. After cooling to RT, the organic layer was washed 6 times with a mixture H2O / MTBE. PGMEA (87 kg) was added and solvent exchange from IPA / MTBE to PGMEA was performed at low pressure. The solid content of the reaction mixture was adjusted to 4% by addition of PGMEA (20 kg). CISiMes (0,041 kg) was added to the reaction mixture, which was further stirred at T = 105 C for 1 , 5h. After cooling to room temperature, about 21 kg of solvents was removed by distillation to get a final solid content of 5.23%. Part of the polymer (7.17 g as 5.23% solid content in PGMEA) was mixed with KY 1901 (0.4% in Novec 7100; 3.12 g), Novec 7100 (5.26 g), IPA (4.67 g), EG (0.62 g) and TEOS-based polymer (as 10% solid content in PGME; 3.75 g).

Composition C-22

AE 3000 (80 g) and KY 1900 (0.1 g) are mixed in IPA (20 g).

Composition C-23

AE 3000 (80 g) and KY 1901 (0.1 g) are mixed in IPA (20 g). c) Preparation Examples for the third coating layer (D) Composition D-l

In a 250 L reactor, TEOS (43,436 kg) was mixed with acetone (136 kg). HNO3 (0.01 M; 2,978 kg) was slowly added to the reaction mixture at RT over 10-20 min. Then, the reaction mixture was refluxed for Ih. After cooling to RT, PGME (115 kg) was added and solvent exchange from acetone / H2O / EtOH to PGME was performed under vacuum. The solid content of the mixture was adjusted to 10% by addition of PGME. Part of the polymer (40 g as 10% solid content in PGME) was mixed with DSX (0.4 % in Novec 7100; 125 g), Novec 7100 (375.3 g), IPA (439 g) and EG (24.8 g).

Composition D-2

In a 250 L reactor, TEOS (43,436 kg) was mixed with acetone (136 kg). HNO3 (0.01 M; 2,978 kg) was slowly added to the reaction mixture at RT over 10-20 min. Then, the reaction mixture was refluxed for Ih. After cooling to RT, PGME (115 kg) was added and solvent exchange from acetone / H2O / EtOH to PGME was performed under vacuum. The solid content of the mixture was adjusted to 10% by addition of PGME. Part of the polymer (10,874 g as 10% solid content in PGME) was mixed with DSX (0.4 % in Novec 7100; 18,125 g), Novec 7100 (54,07 g), PGME (58,74 g) and EG (3,59 g).

Composition D-3

In a IL round bottom flask, TEOS (86 g; 0,412 mol) was dissolved in acetone (272 g). KY 1271 (0,4 g) was added. HNO3 (0.1 M; 59.36 g) was added dropwise and the resulting reaction mixture was refluxed for 2 h. Then, the reaction mixture was cooled to RT. PGME (125.12 g) was added and the solvent exchange procedure from acetone / EtOH / H2O to PGME was performed under vacuum. The solid content of the mixture was adjusted to 10% by addition of PGME. Part of the polymer (8 g as 10% solid content in PGME) was mixed with KY1901 (0.4% in Novec 7100, 35 g), SC019 (0.4% in Novec 7100, 15 g), Novec 7100 (119,2 g), PGME (67,04 g) and EG (4,96 g).

Composition D-4

In a 250 L reactor, TEOS (43,436 kg) was mixed with acetone (136 kg). HNO3 (0.01 M; 2,978 kg) was slowly added to the reaction mixture at RT over 10-20 min. Then, the reaction mixture was refluxed for Ih. After cooling to RT, PGME (115 kg) was added and solvent exchange from acetone / H2O / EtOH to PGME was performed under vacuum. The solid content of the mixture was adjusted to 10% by addition of PGME. Part of the polymer (6 g as 10% solid content in PGME) was mixed with a mixture of KY 1901 (0,675 g) and SC 019 (0,525 g) dissolved in Novec 7100 (32,55 g), PGME (65,68 g), EG (3,72 g) and additional Novec 7100 (41,01 g).

Composition D-5

In a 500ml round bottom flask, MTMS (40 g; 0,2936 mol), TEOS (61,17 g; 0,29364 mol), EtOH (101.17 g; 2,2075 mol) were mixed. Formic acid (0.1M; 74 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The solid content was adjusted to 41.85% with addition of PGME. A part of the previous material was then formulated before performance evaluation as follow: the material (0.47 g) was further diluted with IPA (34.52 g), KY 1901 (0.4% in Novec 7100, 2.5 g) and Novec 7100 (14.96 g).

Composition D-6

In a 500ml round bottom flask, MTMS (40 g; 0,2936 mol), TEOS (61,17 g; 0,29364 mol), EtOH (101.17 g; 2,2075 mol) were mixed. Formic acid (0.1M; 74 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The solid content was adjusted to 41.85% with addition of PGME. A part of the previous material was then formulated before performance evaluation as follow: the material (0.955 g) was further diluted with IPA (46.76 g), EG (2.48 g), KY 1901 (0.4% in Novec 7100, 22.5 g) and Novec 7100 (27.39 g).

Composition D-7

In a 500ml round bottom flask, MTMS (40 g; 0,2936 mol), TEOS (61,17 g; 0,29364 mol), EtOH (101.17 g; 2,2075 mol) were mixed. Formic acid (0.1M; 74 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The solid content was adjusted to 41.85% with addition of PGME. A part of the previous material was then formulated before performance evaluation as follow: the material (1.79 g) was further diluted with IPA (46.10 g), EG (2.48 g), KY 1901 (0.4% in Novec 7100, 22.5 g) and Novec 7100 (27.21 g).

Composition D-8

In a 500ml round bottom flask, MTMS (60 g; 0.44 mol), TEOS (91,76 g; 0,44 mol), EtOH (151.76 g) were mixed. Formic acid (0.1M; 110.99 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The solid content was adjusted to 41.85% with addition of PGME. A part of the previous material was then formulated before performance evaluation as follow: the material (0.89 g) was further diluted with IPA (22.86 g), EG (1.24 g), KY 1901 (0.4% in Novec 7100, 11.25 g), SC 019 (0.4% in Novec 7100, 6.25 g) and Novec 7100 (7.14 g)-

Composition D-9

In a 500ml round bottom flask, MTMS (60 g; 0.44 mol), TEOS (91,76 g; 0,44 mol), EtOH (151.76 g) were mixed. Formic acid (0.1M; 110.99 g) was added dropwise and the reaction mixture was refluxed at T = 105 C for 2 h. The reaction mixture was cooled to room temperature. PGME (100 g) was added and solvent exchange procedure from EtOH to PGME was performed under low pressure. The solid content was adjusted to 41.85% with addition of PGME. A part of the previous material was then formulated before performance evaluation as follow: the material (2.69 g) was further diluted with EG (3.72 g), KY 1901 (0.4% in Novec 7100, 18.75 g), PGME (69.34 g) and Novec 7100 (55.95 g).

4. Preparation and properties of the coatings a) Two-layer coating or three-layer coating on PMMA substrate First Layer (B)

The first layer coating was performed on PMMA (375 pm) using a roll-to-roll pilot apparatus with composition 30. The web speed was 5 m / min and the slot die speed was 650 rpm. The coating was cured with a pre-bake at T = 75 °C for 3 min, followed by UV exposure for 30 s at 1000 W, and then final bake at T = 75 C overwise stated.

The thicknesses of 3 different coated rolls to rolls on 10 various spots in described in Table 1. The average thickness of the coatings is around 5 pm.

Table 1: thicknesses of 3 different coated rolls to rolls in pm

Second Layer (C)

The purpose of the double layer was to reduce reflectance. Depending on the solid content of the material and the amount and nature of additives, the reflection properties varied. The 2^nd layer was added to the PMMA substrate coated with the 1^st layer using the bar coating method. The bar coater can be of different nature for example #1, #2, #3, #4 depending on the targeted thickness. When using bar coater #1, the coating thickness is around 1-2 pm, when using bar coater #2, the coating thickness is around 2-3 pm, when using bar coater #3 the coating thickness is around 5 pm, when using bar coater #4 the coating thickness is around 7-8 pm. A plasma treatment might be needed after coating. The coating was cured in oven at T = 80 °C for Ih.

Third Layer (D)

The purpose of the third layer was to improve the mechanical properties. The bar coating method was also used. The coating was cured in oven at T = 80 °C for Ih.

The following coatings as listed in Table 2 for two-layer coatings and in Table 3 for three layer coatings each on PMMA substrate were applied.

Table 2: two-layer coatings on PMMA substrate

Table 3: three-layer coatings on PMMA substrate

5. Properties of the examples a) Optical properties of two-layer coatings on PMMA substrate Reflectance and transmittance of examples 1, 2, 3, 4, 5, 7 and 8 have been measured. The reflectance of these two-layer coatings over a range of wavelength from 360 nm to 740 nm is illustrated in Figure 1.

The transmittance of these two-layer coatings over a range of wavelength from 360 nm to 740 nm is illustrated in Figure 2.

Table 4 shows the reflectance (R%) and transmittance (T%) of the examples at a wavelength of 550 nm.

Table 4: Reflectance (R%) and transmittance (T%) of the two-layer coatings on PMMA at a wavelength of 550 nm

Table 4 shows that the optical properties vary depending on the composition of the second layer (C) and the thickness of the second layer (C) - indicated in the used bar coater (see Table 2).

Bare PMMA shows a transmittance of 92.98%.

Thus, all examples show improved optical properties. Best optical properties are obtained for example 5. From examples 1 and 2 it can be seen that an increase in the thickness of the second layer (C) improves the optical properties. b) Mechanical properties of two-layer coatings on PMMA substrate

The mechanical properties of examples 5, 6, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18 were measured and are listed in Table 5.

Table 5: mechanical properties of the two-layer coatings on PMMA

Examples 13, 14, 15, 16, 17 and 18 show better mechanical properties compared to examples 5, 6, 9, 10, 11 and 12, especially in regard of abrasion resistance. c) Optical properties of three-layer coatings on PMMA substrate

Reflectance and transmittance of examples 19, 20, 21, 22, 23 and 24 have been measured.

The reflectance of the three-layer coatings of examples 20, 21, 22, 23 and 24 over a range of wavelength from 360 nm to 740 nm is illustrated in Figure 3. The transmittance of the three-layer coatings of examples 20, 21, 22, 23 and 24 over a range of wavelength from 360 nm to 740 nm is illustrated in Figure 4.

In Figures 5 and 6 the reflectance (figure 5) and transmittance (figure 6) over a range of wavelength from 360 nm to 740 nm of the three-layer coating of example 19 is compared with that of the two-layer coating of example 5. It can be seen that the optical properties of the three-layer coating is only slightly impaired compared to the two layer coating.

Table 6 shows the reflectance (R%) and transmittance (T%) of the examples at a wavelength of 550 nm.

Table 6: Reflectance (R%) and transmittance (T%) of the three-layer coatings on PMMA at a wavelength of 550 nm

Bare PMMA shows a transmittance of 92.98%.

Thus, all examples show improved optical properties. d) Mechanical properties of three-layer coatings on PMMA substrate

The mechanical properties of examples 20, 26, 27, 28, 29, 30, 31, 32, 33 and 34 were measured and are listed in Table 7.

Table 7: mechanical properties of the two-layer coatings on PMMA

The three-layer coatings of examples 20 and 26-34 show improved mechanical properties compared to the two layer coating 5 having the same second coating layer. Thus, the mechanical properties of a two coating with good optical but poor mechanical properties can be improved by applying a third coating layer which does not significantly impairs the optical properties but clearly improves the mechanical properties, if needed for the accordant application.

Claims

Claims A layered structure comprising

(A) a substrate layer;

(B) a first coating layer coated on at least one surface of the substrate layer (A) , and

(C) a second coating layer coated on at least one surface of the first coating layer (B) so that the second coating layer (C) is in adherent contact with at least one surface of the first coating layer (B) wherein the first coating layer (B) comprises a first siloxane polymer (B-l); the second coating layer (C) comprises one or more second siloxane polymer(s) (C-l); and the substrate layer (A) is flexible, bendable or both. The layered structure according to claim 1, wherein the first siloxane polymer (B-l) comprises monomer units selected from at least two different silane monomers, wherein at least one of the silane monomers includes an active group capable of achieving cross-linking to adjacent siloxane polymer chains, and wherein the adjacent siloxane polymer chains are crosslinked by means of said an active groups. The layered structure according to claims 1 or 2, wherein the one or more second siloxane polymer(s) (C-l) independently comprise(s) monomer units selected from at least one silane monomer. The layered structure according to any one of claims 1 to 3, wherein the first coating layer (B) has a thickness of 1 to 50 pm, preferably of 2 to 20 pm, more preferably 3 to 10 pm and/or the second coating layer (C) has a thickness of 10 nm to 10 pm, preferably of 25 nm to 8 pm, more preferably 50 nm to 5 pm. 5. The layered structure according to any one of claims 1 to 4, wherein the material of the substrate layer (A) is selected from the group of glass, quartz, silicon, silicon nitride, polymers, metals and plastics and combinations thereof.

6. The layered structure according to claim 5, wherein the plastics are selected from thermoplastic polymers, such as polyolefins, polyesters, polyamides, polyimides, acrylic polymers, such as poly(methylmethacrylate), and Custom Design polymers.

7. The layered structure according to any one of claims 1 to 6, wherein substrate layer (A) has a thickness of 10 to 500 pm, preferably 20 to 400 pm.

8. The layered structure according to any one of claims 1 to 7 further comprising a third coating layer (D) coated on at least one surface of the second coating layer (C) so that the third coating layer (D) is in adherent contact with at least one surface of the second coating layer (C).

9. The layered structure according to claim 8, wherein the third coating layer (D) comprises a siloxane polymer and optionally a fluoropolyether compound.

10. The layered structure according to any one of claims 8 or 9, wherein the third coating layer (D) has a thickness of 10 nm to 10 pm, preferably of 15 nm to 8 pm, more preferably 20 nm to 5 pm.

11. A method for producing a layered structure according to any one of claims 1 to 10 comprising the following steps:

• Providing a first composition comprising at least two different silane monomers, wherein at least one of the silane monomers includes an active group capable of achieving cross-linking to adjacent siloxane polymer; • Subjecting the first composition to at least partial hydrolysis of the monomers to form a composition comprising a first siloxane polymer (B-l);

• Providing a second composition comprising at least one silane monomer;

• Subjecting the second composition to at least partial hydrolysis of the monomers to form a composition comprising one or more second siloxane polymer(s) (C-l);

• Providing a substrate which is flexible or bendable or both;

• Cross-linking the siloxane polymer chains of the second coating layer (C) as to obtain a second coating layer (C) comprising one or more cross-linked siloxane polymer(s) in adherent contact with the first coating layer (B). The method according to claim 11, wherein the first composition comprising a siloxane polymer (B-l) is formed by a method comprising the steps of

• Admixing the at least two different silane monomers in a first solvent to form a mixture;

• Optionally changing the first solvent to a second solvent;

• Optionally subjecting the mixture to further crosslinking by hydrosilylation, thermal or radiation initiation and/or the second composition comprising one or more siloxane polymer(s) is formed by

• Admixing the at least one silane monomer in a first solvent to form a mixture;

• Optionally changing the first solvent to a second solvent.

13. The method according to any one of claims 11 or 12, wherein the first and/or second composition is deposited by spin-on, clip, spray, ink-jet, roll-to-roll, gravure, reverse gravure, bar coating, slot, flexo-graphic, curtain, screen printing coating methods, extrusion coating, dip coating, flow coating or slit coating.

14. The method according to any of claims 11 to 13 further comprising the steps of

15. Use of the layered structure according to any one of claims 1 to 14 for flexible electronics applications, including displays, optical lens, transparent boards, and automotive industries especially as a lightweight alternative to glass.