Pattern-controlled surface relief structures comprising liquid crystals

Abstract

The present invention relates to a process for the production of a security element, which comprises an optical structure with relief effect, comprising a) providing a (flexible) substrate suitable for aligning liquid crystals; b) depositing a curable composition, or a solvent-based composition, comprising a polymer, which is insoluble in the liquid crystal composition from step e) after evaporation of solvent, in a pattern on the substrate; c) optionally evaporating the solvent of the curable composition by applying IR-radiation and / or thermal drying; or evaporating the solvent of the solvent-based composition by applying IR-radiation and / or thermal drying; d) curing the pattern of the curable composition deposited in step b) by means of UV / VIS radiation or electron beam, wherein the curable composition and the solvent-based composition comprise at least one silicone compound having at least one functional group; preferably having at least two functional groups; and / or at least one silicone compound having at least one polymerizable group, especially having at least one ethylenically unsaturated group; preferably having at least two polymerizable groups, especially having at least two ethylenically unsaturated groups; e) applying a liquid crystal composition on at least a part of the substrate and on at least part of the pattern; f) optionally evaporating the solvent of the liquid crystal composition by applying IR-radiation and / or thermal drying; g) curing the liquid crystal composition deposited in step e) by means of UV / VIS radiation or electron beam; and a security element, comprising a substrate suitable for aligning liquid crystals; a pattern deposited on the substrate; and a layer of liquid crystals (i) disposed on at least part of the substrate, a layer of liquid crystals (ii) disposed next to the pattern having a higher thickness than layer (i) (due to dewetting of liquid crystal material from the pattern) and the dewetted pattern (iii). The security element is obtainable by the above-described process and shows different color flop and color intensity in the layers (i) and (ii) of liquid crystals upon tilting of the substrate.

Description

[0001] 241049W001

[0002] 1

[0003] Pattern-controlled surface relief structures comprising liquid crystals

[0004] DESCRIPTION

[0005] The present invention relates to a process for the production of a security element, which comprises an optical structure with relief effect, comprising a) providing a (flexible) substrate suitable for aligning liquid crystals; b) depositing a curable composition, or a solvent-based composition, comprising a polymer, which is insoluble in the liquid crystal composition from step e) after evaporation of solvent, in a pattern on the substrate; c) optionally evaporating the solvent of the curable composition by applying IR- radiation and / or thermal drying; or evaporating the solvent of the solvent-based composition by applying IR-radiation and / or thermal drying; d) curing the pattern of the curable composition deposited in step b) by means of UV / VIS radiation or electron beam, wherein the curable composition and the solventbased composition comprise at least one silicone compound having at least one functional group; preferably having at least two functional groups; and / or at least one silicone compound having at least one polymerizable group, especially having at least one ethylenically unsaturated group; preferably having at least two polymerizable groups, especially having at least two ethylenically unsaturated groups; e) applying a liquid crystal composition on at least a part of the substrate and on at least part of the pattern; f) optionally evaporating the solvent of the liquid crystal composition by applying IR- radiation and / or thermal drying; g) curing the liquid crystal composition deposited in step e) by means of UV / VIS radiation or electron beam; and a security element, comprising a substrate suitable for aligning liquid crystals; a pattern deposited on the substrate; and a layer of liquid crystals (i) disposed on at least part of the substrate, a layer of liquid crystals (ii) disposed next to the pattern and having a higher thickness than layer (i) (due to dewetting of liquid crystal material from the pattern) and the dewetted pattern (iii).

[0006] The security element is obtainable by the above-described process and shows different color flop and color intensity in the layers (i) and (ii) of liquid crystals upon tilting of the substrate.

[0007] TECHNICAL BACKGROUND

[0008] US2023 / 0356541A1 relates to an optical structure with relief effect, comprising: a substrate suitable for aligning liquid crystals; a pattern comprising an ink or a varnish deposited on the substrate; and 241049W001

[0009] 2 a layer of liquid crystals disposed on the substrate and at least partially covering the pattern.

[0010] EP1737677B1 relates to a film (5), in particular an embossing film, laminating film or adhesive film, which comprises at least one anisotropic polymer layer (32) consisting of a liquid crystal material that is at least partially oriented. The anisotropic polymer layer (32) comprises one or more first regions (41 , 43, 45, 48, 50) that form a first security feature. In said regions, the anisotropic polymer layer (32) has linear polarising characteristics or characteristics that allow the polarisation direction to be rotated. The film also comprises one or more second regions (42, 44, 46, 47, 49, 51) that form a second security feature, the anisotropic polymer layer (32) in said regions having circular polarising characteristics. The first security feature can be viewed through a first polariser and the second security feature through a second polariser that responds to another polarisation state.

[0011] US20210086545A1 relates to a process for producing strongly adherent films on a flexible substrate, the process comprising:

[0012] (a) optionally exposing the flexible substrate to a corona discharge or a plasma discharge treatment;

[0013] (b) applying a primer composition on the substrate, the primer composition comprising (b1) a polyurethane (A) comprising as synthesis components (b1a) a polyisocyanate having a functionality of at least 2, (bi b) a compound comprising an isocyanatereactive group and a radically polymerizable unsaturated group, (b1c) a photoinitiator comprising an isocyanate-reactive group, (b2) a polyfunctional polymerizable compound (B), and (b3) a solvent;

[0014] (c) evaporating the solvent by applying IR-radiation and / or thermal drying, to obtain a primer layer on the substrate;

[0015] (d) curing the primer layer by UV / VIS radiation or electron beam, to obtain a primered substrate;

[0016] (e) optionally, exposing the primered substrate to a corona discharge or a plasma discharge treatment;

[0017] (f) applying a curable composition onto the primer coating;

[0018] (g) optionally, contacting at least a portion of the curable composition with surface relief micro-structure former, to obtain an optionally embossed film;

[0019] (h) curing the optionally embossed film by UV / VIS radiation or electron beam; and

[0020] (i) optionally, depositing a layer of a transparent high refractive index material and / or a metallic layer on at least a portion of the cured composition.

[0021] WO2021 / 032518A1 relates to a process for the production of fingerprint texture free liquid crystal films. The process involves the use of liquid crystal compositions comprising at least one photoinitiator, which is an alpha-hydroxy ketone compound of formula (XI), and is suitable for the production of optical films which exhibit excellent 241049W001

[0022] 3 thermal stability at high humidity without losing their other advantages like good resistance against chemicals and solvents. It can be advantageously employed for the production of security elements.

[0023] US10800202B2 relates to a transparent device for document security applications, the device presenting various latent images on each side when in transmission and in reflection mode, characterized in that it comprises: two confinement substrates forming a sandwich-like structure; at least one partially metallized or non-metallized holographic element, the partially metallized holographic element comprising one or more layers of partially metallized material, deposited on at least one of the surfaces of at least one of the confinement substrates, such that a fraction of the incident light is reflected, allowing the remaining fraction of the light to be transmitted, forming reflective holographic images when illuminated; a dichroic dye doped liquid crystal sheet covering the at least one holographic element, the doped liquid crystal sheet oriented according to alignment directions induced in different predefined regions of at least one of the confinement substrates, and wherein the orientation of the different regions of each side of the liquid crystal sheet is established according to at least one alignment pattern, wherein the alignment pattern is obtained through the grooves of the at least one partially metallized or non-metallized holographic element, the orientations differing from one another in a certain angle forming latent images which are different on each side of the sheet and individually visible when illuminated with polarized light, wherein a first alignment pattern induced on one of the faces of the substrate is independent of a second alignment pattern induced on a second of the faces of the substrate and is obtained by at least one technique selected from the group consisting of mechanical rubbing of the alignment layer, photoalignment of a photosensitive material, oblique deposition of an aligner material, alignment via a micrometric or a submicrometric pattern, generation of a pattern of interdigitated electrodes on a surface of the confinement substrate oriented in different directions and combinations thereof.

[0024] EP4279656b1 relates to a method for producing a web-like composite material (30, 30') having a structured surface, comprising the steps of providing a web-like carrier material (5) made of paper and / or plastic, applying a UV-curable lacquer layer (7) of acrylated oligomer onto the carrier material (5), producing a three-dimensional surface structure (13, 13') in the lacquer layer (7) applied to the carrier material (5) and at least partial curing of the lacquer layer (7) by irradiation with high-energy radiation, preferably UV light, characterized in that before the UV-curable lacquer layer (7) is applied, at least one adhesion promoter layer (8) containing acrylated oligomer, a reactive diluent and a photoinitiator reacting to high-energy radiation, preferably UV radiation, is applied onto the carrier material (5), and in that the lacquer layer (7) having the three-dimensional surface structure (13, 13') is cured to such an extent that the composite material (30, 30') in the finished state has an average Martens hardness 241049W001

[0025] 4 according to DIN EN ISO 14577-1 (2003-05) in the range from 10 to 80 N / mm2, preferably in the range from 30 to 80 N / mm2, the indenter used as a test body for measuring the Martens hardness being pressed into the structured surface of the lacquer layer (7).

[0026] EP4279655B1 relates to a method for producing a structuring means (17) for texturing an embossable material surface, in particular a resin-containing laminate surface, comprising the steps of: providing a web-like carrier material (5) made of paper and / or plastic, applying a UV-curable lacquer layer (7) of acrylated oligomer onto the carrier material, forming a three-dimensional embossed structure (13) into the lacquer layer (7) applied to the carrier material (5), and curing the lacquer layer (7) by irradiation with high-energy radiation, preferably UV light, during the forming of the embossed structure (13), characterized in that before the UV-curable lacquer layer (7) is applied, at least one adhesion promoter layer (8) comprising acrylated oligomer, a reactive diluent and a photoinitiator which reacts to high-energy radiation, preferably UV radiation, is applied onto the carrier material, and in that the lacquer layer (7) having the embossed structure (13) is cured by irradiation with high-energy radiation, preferably UV light, to such an extent that, in the finished state, the structuring means (17) has an average Martens hardness according to DIN EN ISO 14577 in the range from 10 to 80 N / mm2, preferably in the range from 30 to 80 N / mm2, the indenter used as a test body for measuring the Martens hardness being pressed into the surface of the lacquer layer (7) having the embossed structure (13).

[0027] EP2261053 relates to a aecurity element (20) for security papers, value documents and the like, having a motif layer, on the basis of a liquid crystal material, that exhibits at least two regions that form a motif, having different orientations of the liquid crystal material and having different polarization effects, characterized in that the liquid crystal material of the motif layer is oriented homogeneously in a first (30) of the motifforming regions, and is oriented homeotropically in a second (34) of the motif-forming regions, such that the motif formed by the two regions is perceptible especially when viewed through a polarizer, and the liquid crystal material of the motif layer in the second region (34) is arranged directly over an inorganic alignment layer (24) formed from aluminum oxide.

[0028] EP2099616 relates to a security element for security papers, value documents and the like, having a motif layer, on the basis of a liquid crystal material, that exhibits at least two regions that form a motif, having different orientations of the liquid crystal material and having different polarization effects, the liquid crystal material of the motif layer being oriented homogeneously in a first of the motif-forming regions, and being oriented isotropically in a second of the motif-forming regions, such that the motif formed by the two regions is perceptible especially when viewed through a polarizer, and the liquid crystal material of the motif layer being arranged, in the second region, 241049W001

[0029] 5 directly over a solubilization layer that is solubilized by the liquid crystal material and prevents the development of a liquid crystal phase in the liquid crystal material.

[0030] EP2196322B1 relates to a security element (1) for securing the authenticity of a value object, such as a security paper, a value document or a branded article, having a layer structure with - at least one layer (5; 7) on the basis of a liquid crystalline material and - at least one lacquer layer (3) to which the liquid crystal layer (5; 7) is applied, characterized in that the lacquer layer (3) is unstructured and consists of a lacquer which is free of liquid crystals and is inert with respect to the liquid crystal layer.

[0031] W02009 / 062867A1 relates to a method for producing a duplicated shim and the duplicated shim obtainable by the method. The duplicated (UV-cured) shim, independent of any carrying device (like a cylinder or belt), can be applied directly to the surface of the transfer roller (and impart the surface OVD structure into a clear lacquer) in a similar way to conventional nickel shims.

[0032] In a preferred embodiment of W02009 / 062867A1 the acrylate formulation comprises Bisphenol A epoxyacrylate diluted with 25% of tripropyleneglycol diacrylate (TPGDA), a propoxylated / ethoxylated pentaerythritol tetraacrylate, propoxylated glycerol triacrylate, tripropyleneglycol diacrylate, silicone hexaacrylate, photoinitiators, such as 4- phenylbenzophenone and Esacure KIP 150, and a silicone additive, such as Dow Corning 57. Typically photoinitiators are present in an amount of 0.5-10 %. An amine modified acrylate and trimethylolpropane triacrylate may optionally be present.

[0033] In Example 1 of W02014041121A1 7g UV varnish containing 5% Photoinitiator (% by weight, based on the total weight) are added to 3g silver platelets dispersion (50% pigment in cyclohexanone) in a 20ml_ glass bottle and gently stirred at room temperature. The obtained ink is coated by the means of a wire bar (4 micron wet ink thickness) on a volume hologram manufactured according to W02005 / 124456 on PET film and air dried. The coated film is pressed against a shim containing the holographic structure and is cured under UV light (Aktiprint® 18 / 2, 80W / cm,10 m / min) through the film. The PET film is peeled off the shim.

[0034] The composition of the UV lacquer is shown below: 241049W001

[0035] 6

[0036] In Example 1 of WO2019 / 206845 The PET foil coated with the primer formulation is overprinted with UV curable composition using a 70l / cm gravure cylinder and UV casting is done on a nickel shim containing holographic structures using a UV lamp GEW, E2C-35-3 mercury lamp (140W / cm), 50% power intensity, 5 bar pressure on nip rollers at 30m / min. The UV curable composition is shown below:

[0037] US10809622B2 relates to an embossing lacquer based on a UV-polymerizable prepolymer composition containing at least one acrylate monomer, wherein the prepolymer composition contains a thiol, selected from the group consisting of 3- mercaptopropionates, mercaptoacetates, thioglycolates, and alkyl thiols, as well as a surface-active anti-adhesive additive selected from the group consisting of monofunctional polydimethylsiloxane (meth) acrylates, perfluoro-n-alkyl (meth) acrylates and perfluoropolyether (meth) acrylates, as well as a photoinitiator, wherein the surfaceactive anti-adhesive additive is contained in a quantity of 0.1 wt % to 3 wt % of the UV- polymerizable prepolymer composition, and wherein the embossing lacquer is water soluble after polymerization.

[0038] EP2886343A1 describes an optical structure comprising a substrate, a primer formed on the substrate and a UV-cross-linkable layer which is disposed on the primer. The UV-cross-linkable layer can comprise liquid crystals and is embossed, so as to obtain a three-dimensional visual effect.

[0039] There is consequently a need to benefit from new optical structures capable of obtaining a dynamic optical effect while being relatively simple and economical to produce.

[0040] The invention aims to address this need, and it achieves this by virtue by providing a surface relief structure of liquid crystals, which provides areas with a higher liquid crystal layer thickness, which appear more intensely coloured and show a different colour shift behaviour.

[0041] Accordingly, the present invention relates to a process for the production of a security element, which comprises an optical structure with relief effect, comprising 241049W001

[0042] 7 a) providing a (flexible) substrate suitable for aligning liquid crystals; b) depositing a curable composition, or a solvent-based composition, comprising a polymer, which is insoluble in the liquid crystal composition from step e) after evaporation of solvent, in a pattern on the substrate; c) optionally evaporating the solvent of the curable composition by applying IR- radiation and / or thermal drying; or evaporating the solvent of the solvent-based composition by applying IR-radiation and / or thermal drying; d) curing the pattern of the curable composition deposited in step b) by means of UV / VIS radiation or electron beam, wherein the curable composition and the solventbased composition comprise at least one silicone compound having at least one functional group; preferably having at least two functional groups; e) applying a liquid crystal composition on at least a part of the substrate and on at least part of the pattern; f) optionally evaporating the solvent of the liquid crystal composition by applying IR- radiation and / or thermal drying; g) curing the liquid crystal composition deposited in step e) by means of UV / VIS radiation or electron beam; and a security element, comprising a substrate suitable for aligning liquid crystals; a pattern deposited on the substrate; and a layer of liquid crystals (i) disposed on at least part of the substrate, a layer of liquid crystals (ii) disposed next to the pattern having a higher thickness than layer (i) (due to dewetting of liquid crystal material from the pattern) and the dewetted pattern (iii).

[0043] In a second embodiment, the present invention relates to a process for the production of a security element, which comprises an optical structure with relief effect, comprising a) providing a (flexible) substrate suitable for aligning liquid crystals; b) depositing a curable composition, or a solvent-based composition, comprising a polymer, which is insoluble in the liquid crystal composition from step e) after evaporation of solvent, in a pattern on the substrate; c) optionally evaporating the solvent of the curable composition by applying IR- radiation and / or thermal drying; or evaporating the solvent of the solvent-based composition by applying IR-radiation and / or thermal drying; d) curing the pattern of the curable composition deposited in step b) by means of UV / VIS radiation or electron beam, wherein the curable composition and the solventbased composition comprise at least one silicone compound having at least one polymerizable group, especially having at least one ethylenically unsaturated group; preferably having at least two polymerizable groups, especially having at least two ethylenically unsaturated groups; e) applying a liquid crystal composition on at least a part of the substrate and on at least part of the pattern; 241049W001

[0044] 8 f) optionally evaporating the solvent of the liquid crystal composition by applying IR- radiation and / or thermal drying; g) curing the liquid crystal composition deposited in step e) by means of UV / VIS radiation or electron beam; and a security element, comprising a substrate suitable for aligning liquid crystals; a pattern deposited on the substrate; and a layer of liquid crystals (i) disposed on at least part of the substrate, a layer of liquid crystals (ii) disposed next to the pattern and having a higher thickness than layer (i) (due to dewetting of liquid crystal material from the pattern) and the dewetted pattern (iii).

[0045] The liquid crystal composition is practically completely de-wetted from the de-wetting pattern obtained in step d).

[0046] The security elements are obtainable by the above-described process and shows different color flop and color intensity in the layers (i) and (ii) of liquid crystals upon tilting of the substrate.

[0047] “Dewetting” is defined according to the present invention as the disappearance of a thin liquid crystal film from the pattern and the formation of a layer of liquid crystals (ii) disposed next to the pattern and having a higher thickness than a layer of liquid crystals (i) disposed on the substrate at a distance from the pattern where no increase of the thickness due to the dewetting occurs. In other words, the security element has varying thicknesses of the liquid crystal layer when drying. The liquid crystal film recedes from the pattern and leads to a layer of liquid crystals (ii) disposed next to the pattern having increased thickness.

[0048] “Pattern” according to the present invention means a design, which may have a form of an image, regular or irregular combination of straight or curved lines, dots and other structural motifs, such as, for example, ovals, which may be applied by any printing technique known in the prior art. Preferably, the pattern comprises structural motifs with a width or diameter of 0.1 to 3 millimeters, more preferably 0.2 to 2 millimeters.

[0049] Functional groups are, for example, NHR’ groups, OH groups and SH groups. NHR’ groups and OH groups are preferred.

[0050] Polymerizable groups are, for example, epoxy groups, oxetane groups and especially ethylenically unsaturated groups, such as, for example, vinyl ether groups and (meth)acrylate groups. Vinyl ether groups and (meth)acrylate groups are preferred. (Meth)acrylate groups are more preferred. 241049W001

[0051] 9

[0052] Fig. 1 is a flowchart of the process of the present invention.

[0053] A pattern, i.e. the letters A, B and C, with a UV curable composition, comprising a silicone compound having at least one functional group and / or a silicone compound having at least one polymerizable group is printed on a substrate with good alignment properties for the liquid crystal and cured. A liquid crystal composition is applied to the pattern and part of the substrate, dried and cured, resulting in an aligned layer of liquid crystals with homogeneous thickness (light grey), complete dewetted pattern and areas of aligned of liquid crystals around the pattern with higher thickness (dark grey).

[0054] Fig. 2 shows an illustration of a security element, obtainable according to the present invention with Silmer NH Di-50 in the dewetting varnish, where the liquid crystal layer is almost completely dewetted from the rainbow pattern and the areas between the lines of the pattern showing a color different from that of liquid crystal layer (i) on surrounding substrate areas under the same observation angle.

[0055] Fig. 3 shows an illustration of a security element, obtainable according to the present invention with SilmerOACR Di-10, where the liquid crystal layer is almost completely dewetted from the rainbow pattern and the areas between the lines of the pattern showing a color different from that of liquid crystal layer (i) on surrounding substrate areas under the same observation angle.

[0056] Because the curable composition (or solvent-based composition) comprises a silicone compound having at least one functional group and / or a silicone compound having at least one polymerizable group, it has significantly lower surface tension, compared to blank substrate, and therefore, de-wetting properties. If a liquid crystal pattern is applied to the layer derived from the curable composition and obtained in step d) of the process of the present invention, the liquid crystal layer is practically completely dewetted from the de-wetting pattern, forming areas with higher liquid crystal layer thickness between the lines or other structural motifs of de-wetting pattern, thus creating a surface relief structure of liquid crystals. The thus created surface relief structure of liquid crystals appears more intensely coloured than the flat liquid crystal coating at the same observation angle. In addition, it shows a different colour shift behaviour as compared to flat liquid crystal layer.

[0057] In a particularly preferred embodiment, the functional group can either react chemically with uncured UV-curable varnish, for example, amino, or thiol group in a (meth)acrylate or epoxy compound comprising varnish, or react chemically during UV-curing of dewetting varnish, for example, hydroxy, or mercapto group in a cationically curable UV- varnish. 241049W001

[0058] 10

[0059] Areas of LC layers with varying thickness due to the pattern having de-wetting characteristics can create a kind of moving effect upon tilting of the substrate.

[0060] The curable composition, or solvent-based composition can be colored.

[0061] In process step b) the curable composition, or solvent-based composition is preferably printed, especially by ink-jet printing. This method notably allows: the deposition of small quantities of substance per unit of surface area, and / or customization of the patterns without requiring any printing form.

[0062] As a variant, it can also be deposited by a flexographic printing method, or other printing methods known in the art.

[0063] Preferably, in order for the relief visual effect to be relatively pronounced, the dry weight of substance, expressed on the basis of the area of the face of the substrate covered by the deposit, is less than or equal to 15 g / m2, preferably less than or equal to 12 g / m2, even better between 0.1 g / m2and 7 g / m2.

[0064] In process step c) and f) the evaporating of the solvent is done by applying infrared radiation (IR radiation), and / or thermal drying, for example, by means of hot air, a hot plate, or roller.

[0065] The evaporating of the solvent is affected preferably at elevated temperature, i.e. by heating, optionally under reduced pressure. It is preferred to carry out process step (c) at a temperature of from 40 to 150°C, more preferably from 60 to 130°C. The thermal energy can originate both from an external heat source as well as from the UV light source, for example a UV lamp. Preferably the thermal energy originates at least partly from a heat source different from the UV light source, for example from an oven, air dryer, IR dryer, or a heating plate.

[0066] Radiation curing in process steps d) and g) takes place with high-energy light, such as, for example, UV / VIS radiation, or electron beam. Radiation curing may also take place at relatively high temperatures.

[0067] Examples of suitable radiation sources for the radiation cure are low-pressure mercury lamps, medium-pressure mercury lamps with high-pressure lamps, and fluorescent tubes, pulsed lamps, metal halide lamps, or excimer lamps and also UV LEDs. The radiation cure is accomplished by exposure to high-energy radiation, i.e., UV / VIS radiation, preferably light in the wavelength range of =200 to 700 nm, more preferably =200 to 500 nm, or by exposure to high-energy electrons (electron beams; 60 to 300 keV). Examples of radiation sources used include high-pressure mercury vapor lamps, lasers, pulsed lamps (flash light), halogen lamps, UV LEDs, or excimer lamps. The 241049W001

[0068] 11 radiation dose normally sufficient for crosslinking in the case of UV curing is in the range from 30 to 3000 mJ / cm2.

[0069] The liquid crystal composition can be applied in process step e) by means of customary processes, for example by means of processes selected from airblade coating, knife coating, airknife coating, squeegee coating, impregnation coating, reverse roll coating, transfer roll coating, gravure coating, kiss coating, flow coating, spray coating, spin coating, or printing processes such as relief printing, gravure printing, intaglio printing, flexographic printing, offset printing, inkjet printing, letterpress printing, pad printing, heatseal printing or screen printing processes.

[0070] The liquid crystal composition is preferably applied by slot die-, knive-, reverse roll-, metering rod coating, gravure-, flexo-, screen-, or inkjet printing.

[0071] If this has not already been accomplished by the process of application, the composition applied has to be aligned before the polymerization step. The alignment of the liquid-crystalline layer generally proceeds spontaneously during the applying operation; it can, however, also be affected in a downstream step. In this case, the alignment is affected by means of the known methods, for example the interaction of the liquid-crystal phase with alignment layers, the application of electrical or magnetic fields and the mechanical knife coating of the liquid-crystal layers. However, the alignment preferably proceeds spontaneously under the action of the shear forces which act in the course of application.

[0072] Substrate

[0073] The substrate is suited to the alignment of the liquid crystals. In particular, it can have a surface texture suited to the alignment of the liquid crystals. Preferably, the substrate comprises a film stretched axially or preferably biaxially.

[0074] The substrate (film) is produced in a plastic material, chosen from among a polyester, notably polyethylene terephthalate, also called PET, polypropylene, polyethylene and the mixtures thereof. The substrate is preferably made of PET, or polypropylene. The stretching promotes the alignment of the liquid crystals.

[0075] The film can have a thickness of between 6 pm and 500 pm. For example, it has a thickness of between 12 pm and 50 pm.

[0076] The substrate can also comprise a layer of a primer, notably an adhesion primer, which covers, preferably entirely, one face of the film and is in contact with the film and with the layer of liquid crystals. The adhesion primer increases the adhesion of the liquid crystals to the substrate without preventing the film from contributing through its intrinsic structure to the alignment of the liquid crystals. 241049W001

[0077] 12

[0078] The thickness of the adhesion primer is preferably less than 1000 nm, preferably less than 100 nm. The adhesion primer can comprise a polyolefin, preferably chosen from among polyethylene, polyurethane, polyester, polycarbonate and polyacrylic, one of the copolymers thereof. Preferably, it comprises a polyacrylic.

[0079] Solvent-based Composition

[0080] The solvent-based composition usually comprises at least one polymer, at least one solvent, the silicone compound having at least one functional group and / or the silicone compound having at least one polymerizable group and optionally further additives.

[0081] The polymer is insoluble in the liquid crystal composition from step e) after evaporation of solvent of the solvent-based composition. That is, there is no dissolution of the polymer when the liquid crystal composition is applied in step e) resulting in mixing of the layers, at least not to an extent that produces an optical effect on the liquid crystal layer.

[0082] The solvent-based composition and the liquid crystal composition must therefore be matched to each other. A liquid crystal composition, which dissolves a certain polymer is unsuitable for it, but may be inert to another polymer. Appropriate coordination of material properties is within the general knowledge of a skilled person.

[0083] Examples of solvents are in principal the same as mentioned with respect to the liquid crystal composition. Solvents which can be used in combination with the liquid crystal compositions exemplified in the present application and comprising cyclopentanone as solvent, are ethanol, methanol and water.

[0084] Examples of polymers are polyamide resins from Huntsman, such as, for example, Eurelon® 930 and 945.

[0085] Eurelon® 930 can be used as a solution consisting of 20% by weight Eurelon® 930, 40% by weight toluene and 40% by weight ethanol. Eurelon® 945 can be used as a solution consisting of 20% by weight Eurelon 945, 39% by weight toluene, 40% by weight ethanol and 1% by weight Laropal® A81 (urea aldehyde resin).

[0086] The Eurelon® 930 and 945 compositions (including the silicone compound having at least one functional group and / or the silicone compound having at least one polymerizable group) can be used in combination with the liquid crystal compositions exemplified in the present application and comprising cyclopentanone as solvent.

[0087] Further examples of polymers, which can be used in combination with the liquid crystal compositions exemplified in the present application and comprising cyclopentanone as 241049W001

[0088] 13 solvent, are polar polymers, which are soluble in ethanol, methanol and water, such as, for example, hydroxyethyl cellulose based polymers and polyvinylalcohol.

[0089] Curable Composition

[0090] The curable composition is more preferred than the solvent-based composition.

[0091] The curable composition is preferably a UV curable composition, which comprises preferably a) 1 .0 to 20.0, especially 1 .0 to 15.0, very especially 2.0 to 10.0 % by weight of photoinitiator,

[0092] (b) 99.0 to 80.0, especially 99.0 to 85.0, very especially 98.0 to 90.0 % by weight of a binder (compound(s) including one or more polymerizable groups; especially unsaturated compound(s) including one or more olefinic double bonds),

[0093] (c) 0.01 to 5.0, especially 0.02 to 3.0, very especially 0.05 to 2.0 % by weight of at least one silicone compound, having at least one functional group and / or at least one silicone compound having at least one polymerizable group, and

[0094] (d) 0 to 5.0 %, especially 0 to 3.0, very especially 0 to 2.0 % by weight of auxiliary formulation additives, such as, for example, adhesion promoters, levelling agents, rheology modifiers and the like, wherein the sum of components a), b), c) and d) adds up to 100%.

[0095] In a preferred embodiment the UV curable composition comprises an epoxy-acrylate (10 to 60%) and one or several (monofunctional and multifunctional) acrylates (20 to 90%) and one, or several photoinitiators (1 to 15%).

[0096] The epoxy-acrylate is selected from aromatic glycidyl ethers aliphatic glycidyl ethers. Aromatic glycidyl ethers are, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether, bisphenol S diglycidyl ether, hydroquinone diglycidyl ether, alkylation products of phenol / dicyclopentadiene, e.g., 2,5-bis[(2,3- epoxypropoxy)phenyl]octahydro-4,7-methano-5H-indene (CAS No. [13446-85-0]), tris[4-(2,3-epoxypropoxy)phenyl]methane isomers (CAS No. [66072-39-7]), phenol- based epoxy novolaks (CAS No. [9003-35-4]), and cresol-based epoxy novolaks (CAS No. [37382-79-9]). Examples of aliphatic glycidyl ethers include 1 ,4-butanediol diglycidyl ether, 1 ,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1 ,1 ,2,2-tetrakis[4-(2,3-epoxypropoxy)phenyl]ethane (CAS No. [27043-37-4]), diglycidyl ether of polypropylene glycol (a,w-bis(2,3- epoxypropoxy)poly(oxypropylene), CAS No. [16096-30-3]) and of hydrogenated bisphenol A (2, 2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane, CAS No. [13410-58-7]).

[0097] The one or several acrylates are preferably multifunctional monomers which are selected from trimethylolpropane triacrylate, trimethylolethane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylene 241049W001

[0098] 14 glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), dipropylene glycol diacrylate (DPGDA), pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexa-,acrylate, tripentaerythritol octaacrylate, pentaerythritol dimethacrylate, pentaerythritol trimeth-'acrylate, dipentaerythritol dimethacrylate, dipentaerythritol tetramethacrylate, tripenta-'erythritol octamethacrylate, pentaerythritol diitaconate, dipentaerythritol tris- itaconate, dipen-'taerythritol pentaitaconate, dipentaerythritol hexaitaconate, ethylene glycol diacrylate, 1 ,3-bu-,tanediol diacrylate, 1 ,3-butanediol dimethacrylate, 1 ,4- butanediol diitaconate, sorbitol triacryhate, sorbitol tetraacrylate, pentaerythritol- modified triacrylate, sorbitol tetra methacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, oligoester acrylates and methacrylates, glycerol diacrylate and triacrylate, 1 ,4-cyclohexane diacrylate, bisacrylates and bismethacrylates of polyethylene glycol with a molecular weight of from 200 to 1500, triacrylate of singly to vigintuply alkoxylated, more preferably singly to vigintuply ethoxylated trimethylolpropane, singly to vigintuply propoxylated glycerol or singly to vigintuply ethoxylated and / or propoxylated pentaerythritol, such as, for example, ethoxylated trimethylol propane triacrylate (TMEOPTA) and or mixtures thereof.

[0099] The photoinitiator is preferably a blend of an alpha-hydroxy ketone, alpha-alkoxyketone or alpha-aminoketone compound of the formula (XI) and a benzophenone compound of the formula (X); or a blend of an alpha-hydroxy ketone, alpha-alkoxyketone or alpha- aminoketone compound of the formula (XI), a benzophenone compound of the formula (X) and an acylphosphine oxide compound of the formula (XII).

[0100] In another preferred embodiment the UV curable composition comprises:

[0101] Bisphenol A epoxyacrylate with 25% TPGDA 1 - 35 % by weight

[0102] Dipropylene glycol diacrylate (DPGDA) 30 - 45 % by weight

[0103] Ethoxylated trimethylol propane triacrylate (TMEOPTA) 10 - 50% by weight

[0104] Reactive tertiary amine 0 - 15% by weight

[0105] Photoinitiator: 5 - 10 % by weight

[0106] Silicone cpd(s), having at least one functional group 0.05 to 2.0 % by weight

[0107] In another preferred embodiment the UV curable composition comprises:

[0108] Tripropylene glycol diacrylate (TPGDA) 1 - 25 % by weight

[0109] Dipropylene glycol diacrylate (DPGDA) 30 - 45 % by weight

[0110] Ethoxylated trimethylol propane triacrylate (TMEOPTA) 10 - 50% by weight

[0111] Reactive tertiary amine 0 - 15% by weight

[0112] Photoinitiator: 5 - 9 % by weight

[0113] Silicone cpd(s), having at least one functional group 0.05 to 2.0 % by weight 241049W001

[0114] 15

[0115] In another preferred embodiment the UV curable composition comprises: Bisphenol A epoxyacrylate with 25% TPGDA 1 - 35 % by weight

[0116] Dipropylene glycol diacrylate (DPGDA) 30 - 45 % by weight

[0117] Ethoxylated trimethylol propane triacrylate (TMEOPTA) 10 - 50% by weight Reactive tertiary amine 0 - 15% by weight

[0118] Photoinitiator: 5 - 10 % by weight

[0119] Silicone compound, having at least one pol. group 0.05 to 2.0 % by weight

[0120] In another preferred embodiment the UV curable composition comprises:

[0121] Tripropylene glycol diacrylate (TPGDA) 1 - 25 % by weight

[0122] Dipropylene glycol diacrylate (DPGDA) 30 - 45 % by weight

[0123] Ethoxylated trimethylol propane triacrylate (TMEOPTA) 10 - 50% by weight Reactive tertiary amine 0 - 15% by weight

[0124] Photoinitiator: 5 - 9 % by weight

[0125] Silicone compound, having at least one pol. group 0.05 to 2.0 % by weight

[0126] The photoinitiator is preferably a blend of an alpha-hydroxy ketone, alpha-alkoxyketone or alpha-aminoketone compound of the formula (XI) and a benzophenone compound of the formula (X); or a blend of an alpha-hydroxy ketone, alpha-alkoxyketone or alpha- aminoketone compound of the formula (XI), a benzophenone compound of the formula (X) and an acylphosphine oxide compound of the formula (XII).

[0127] The curable composition may comprise various additives. Examples thereof include thermal inhibitors, coinitiators and / or sensitizers, light stabilisers, optical brighteners, fillers and pigments, as well as white and coloured pigments, dyes, antistatics, wetting agents, flow auxiliaries, lubricants, waxes, anti-adhesive agents, dispersants, emulsifiers, anti-oxidants; fillers, e.g. talcum, gypsum, silicic acid, rutile, carbon black, zinc oxide, iron oxides; reaction accelerators, thickeners, matting agents, antifoams, leveling agents and other adjuvants customary, for example, in lacquer, ink and coating technology.

[0128] Examples of coinitiators / sensitisers are especially aromatic carbonyl compounds, for example benzophenone, thioxanthone, especially isopropyl thioxanthone, anthraquinone and 3-acylcoumarin derivatives, terphenyls, styryl ketones, and also 3-(aroylmethylene)- thiazolines, camphor quinone, and also eosine, rhodamine and erythrosine dyes. Amines, for example, can also be regarded as photosensitisers when the photoinitiator consists of a benzophenone or benzophenone derivative.

[0129] In a further embodiment of the present invention the ultraviolet coating can be coloured. That is the curable composition may comprise pigments and / or dyes. The pigments can be transparent organic color pigments or inorganic pigments. 241049W001

[0130] 16

[0131] Suitable colored pigments especially include organic pigments selected from the group consisting of azo, azomethine, methine, anthraquinone, phthalocyanine, perinone, perylene, diketopyrrolopyrrole, thioindigo, dioxazine iminoisoindoline, dioxazine, iminoisoindolinone, quinacridone, flavanthrone, indanthrone, anthrapyrimidine and quinophthalone pigments, or a mixture or solid solution thereof; especially a dioxazine, diketopyrrolopyrrole, quinacridone, phthalocyanine, indanthrone or iminoisoindolinone pigment, or a mixture or solid solution thereof.

[0132] Examples of dyes, which can be used to color the curable composition, are selected from the group consisting of azo, azomethine, methine, anthraquinone, phthalocyanine, dioxazine, flavanthrone, indanthrone, anthrapyrimidine and metal complex dyes. Monoazo dyes, cobalt complex dyes, chrome complex dyes, anthraquinone dyes and copper phthalocyanine dyes are preferred.

[0133] Silicone compound having at least one functional group

[0134] The silicone compound has at least one functional group; preferably at least two functional groups. Mixtures of different silicone compounds, silicone compounds having different functional groups and silicone compounds having at least one functional group as well as at least one (meth)acrylate group and may be used.

[0135] Preferred functional groups are NHR’ groups, OH groups and SH groups. NHR’ groups and OH groups are more preferred.

[0136] The silicone compound that can have one, two, three, four, or even more functional groups.

[0137] As example of a polysiloxane having amino or thiol groups that may be used in the context of the invention, one may cite Silmer® NH Di 50 and Silmer® SH JO sold by Siltech Corporation. As example of a polysiloxane having both, functional (hydroxy) and polymerizable groups one may cite Silmer® OH ACR series or products.

[0138] The silicone compound is preferably a hydroxyl or amino difunctionalised polysiloxane of formula A: (A), wherein

[0139] -Q- represents a Ci-C2oalkylene group, eventually in which one or more -CH2- are replaced by -O-, or represents a C6-C22arylene group,

[0140] W represents -OH or -NHR', with R' representing -H, a Ci-CiOalkyl group, or a C6- C22aryl group, 241049W001

[0141] 17

[0142] -R111represents - independently in each occurrence - a Ci-C2oalkyl group, which may be interrupted by one or more oxygen atoms and / or eventually substituted by one or more -SH, -NH2, -F, -OH, -CH3and / or -Cl, especially a Ci-C20alkyl group, eventually substituted by one or more -SH, -NH2, -F and / or -Cl, and a is an integer ranging from 30 to 1000.

[0143] R111can have different meanings within one compound. In one embodiment R111represents a methyl group and a 3-aminopropyl group with molar ratio of methyl groups to 3-aminopropyl groups being higher than 5. In another embodiment R111represents a methyl group and a 3-mercaptopropyl group with molar ratio of methyl groups to 3- mercaptopropyl groups being higher than 5. In another embodiment R111represents a methyl group and a polyethylene glycol group with a terminal OH, or OCH3group, with molar ratio of methyl groups to a polyethylene glycol group having terminal OH or OCH3groups being higher than 5.

[0144] By "alkylene", it is meant a divalent alkyl group. Unless otherwise specified, the alkyl group may be branched or linear.

[0145] By "arylene", it is meant a divalent aryl group.

[0146] By "aryl", it is meant, unless otherwise specified, a mono-, bi- or polycyclic unsaturated hydrocarbonated 5-24 membered ring comprising at least one aromatic ring. Phenyl, naphtyl, anthrancenyl, phenanthrenyl and cinnamyl are example of aryl groups. Advantageously, -W represents -NHR'. According to this embodiment, -R' is preferably chosen among -H, a Ci-CiOalkyl group, and a C6-Ci8aryl group, more preferably among -H, a Ci-C6alkyl group, and a C6-Ci0aryl group, and even more preferably among -H, a Ci-C6alkyl group, and a C6-aryl group. In a particularly preferred embodiment, -R' is chosen among -H, and a Ci-C6alkyl group such as methyl, ethyl, propyl, butyl, pentyl and hexyl. In a particular embodiment, -W represents -NH2. While not preferred, -W may represent -OH.

[0147] Advantantageously, -Q- represents a Ci-CiOalkylene group, eventually in which one or more -CH2- are replaced by -O-, or represents a C6-Ci8arylene group, more preferably Ci-CiOalkylene group, eventually in which one or more -CH2- are replaced by -O-, or a C6-Cioarylene group, and even more preferably Ci-CiOalkylene group, eventually in which one or more -CH2- are replaced by -O-, or represents a C6-arylene group. Particularly preferred -Q- groups are Ci-CiOalkylene group, preferably C2-Ci0alkylene group, even more preferably C2-C6alkylene group, eventually in which one or more - CH2- are replaced by -O-. In a preferred embodiment no -CH2- of -Q- is replaced by -O- . As examples of preferred -Q groups, ethylene, propylene, butylene, pentylene and hexylene may be cited, and in particular propylene. 241049W001

[0148] 18

[0149] Advantageously, -R111represents a Ci-CiOalkyl group, eventually substituted by one or more -F and / or -Cl, preferably a Ci-C6alkyl group eventually substituted by one or more -F and / or -Cl. Preferably, -R111is not substituted by any -F and / or -Cl. Examples of particularly preferred -R111groups are methyl, ethyl, propyl, butyl, pentyl and hexyl groups, and in particular methyl.

[0150] Advantageously, a is an integer ranging from 30 to 1000, preferably from 30 to 700, even more preferably from 30 to 400, and even more preferably 30 to 150.

[0151] In a particular embodiment, -W represents -NHR' with -R' as defined above, and -Q- represents a Ci-CiOalkylene group, eventually in which one or more -CH2- are replaced by -O-, or represents a C6-Ci8arylene group.

[0152] In a particular embodiment, -W represents -NHR' with -R' representing -H, a Ci-CiOalkyl group, or a C6-Ci8aryl group , and -Q- represents a Ci-CiOalkylene group, eventually in which one or more -CH2-are replaced by -O-.

[0153] In a particular embodiment, -W represents -NHR' with -R' representing -H, a Ci-C6alkyl group, or a C6-aryl group, and -Q- represents a C2-Ci0alkylene group.

[0154] In a particular embodiment, -W represents -NH2and -Q- represents a C2-C6alkylene group.

[0155] In a particular embodiment, -R111represents Ci-CiOalkyl group eventually substituted by one or more -F and / or -Cl, -W represents -NHR' with -R' as defined above, and -Q- represents a Ci-CiOalkylene group, eventually in which one or more -CH2- are replaced by -O-, or represents a C6-Ci8arylene group.

[0156] In a particular embodiment, -R111represents a Ci-C6alkyl group eventually substituted by one or more -F and / or -Cl, -W represents -NHR' with -R' representing -H, a Ci- Cioalkyl group, or a C6-Ci8aryl group, and -Q- represents a C2-Ci0alkylene group, eventually in which one or more -CH2- are replaced by -O-.

[0157] In a particular embodiment, -R111represents a Ci-C6alkyl group, -W represents -NHR' with -R' representing -H, a Ci-C6alkyl group, or a C6-aryl group, and -Q- represents a C2-Ci0alkylene group.

[0158] In a particular embodiment, -R111represents a methyl group, -W represents -NH2and - Q- represents a C2-C6alkylene group.

[0159] In a preferred embodiment, -R111represents Ci-CiOalkyl group eventually substituted by one or more -F and / or -Cl, -W represents -NHR' with -R' as defined above, and -Q- represents a Ci-CiOalkylene group, eventually in which one or more -CH2- are replaced by -O-, or represents a C6-Ci8arylene group and a is an integer ranging from 30 to 1000, preferably 30 to 700.

[0160] In a particularly preferred embodiment, -R111represents a methyl group, -W represents -NH2, -Q- represents a C2-C6alkylene group, and a is an integer ranging from 30 to 150. As example of long chain hydroxyl or amino difunctionalised polysiloxane of formula A that may be used in the context of the invention, one may cite bisaminopropyl- terminated polydimethylsiloxane, such as Silmer® NH Di-50 sold by Siltech.

[0161] Silicone compound having at least one polymerizable group 241049W001

[0162] 19

[0163] In another embodiment of the present application the silicone compound has at least one polymerizable group; preferably at least two polymerizable groups,

[0164] Examples of polymerizable groups are epoxy groups and oxetane groups, especially ethylenically unsaturated groups, such as, for example, vinyl ether groups and (meth)acrylate groups. Vinyl ether groups and (meth)acrylate groups are preferred. (Meth)acrylate groups are more preferred.

[0165] The silicone compound has preferably at least one ethylenically unsaturated group; more preferably at least two ethylenically unsaturated groups.

[0166] The silicone compound that can have one, two, three, four, or even more ethylenically unsaturated groups. In many embodiments, the ethylenically unsaturated group is a (meth)acryloyl group or a vinyl group, which include vinyl ether groups. The ethylenically unsaturated group is preferably a (meth)acryloyl group or a vinyl group, which include vinyl ether groups.

[0167] The silicone compound is preferably a compound of formula H2C=CR2-R3-Q2-Y1-Q1-Y1- Q2-R3-CR2=CH2(I), wherein

[0168] Q1is a polydiorganosiloxane group,

[0169] Q2is S, NR4, or O, especially NR4, or O, very especially O, and each Y1is an alkylene, arylene, aralkylene, or a combination thereof; each R2is a hydrogen or methyl; each R3is a single bond or is a divalent group selected from a carbonyl, carbonylimino, carbonyloxy, imino, oxy, alkylene, alkylene substituted with a hydroxyl group, aralkylene, and a combination thereof, and each R4is hydrogen or an alkyl, and each Y1is independently an alkylene, aralkylene, or a combination thereof.

[0170] Suitable alkyl groups for R1in the polydiorganosiloxane group Q1typically have 1 to 10, 1 to 6, or 1 to 4 carbon atoms. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, isopropyl, n-propyl, n-butyl, and iso-butyl. Suitable haloalkyl groups for R1often have only a portion of the hydrogen atoms of the corresponding alkyl group replaced with a halogen. Exemplary haloalkyl groups include chloroalkyl and fluoroalkyl groups with 1 to 3 halo atoms and 3 to 10 carbon atoms. Suitable alkenyl groups for R1often have 2 to 10 carbon atoms. Exemplary alkenyl groups often have 2 to 8, 2 to 6, or 2 to 4 carbon atoms such as ethenyl, n-propenyl, and n-butenyl. Suitable aryl groups for R1often have 6 to 12 carbon atoms. Phenyl is an exemplary aryl group. The aryl group can be unsubstituted or substituted with an alkyl (e.g., an alkyl having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), an alkoxy (e.g., an alkoxy having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), or halo (e.g., chloro, bromo, or fluoro). Suitable aralkyl groups for R1usually have an 241049W001

[0171] 20 alkylene group with 1 to 10 carbon atoms and an aryl group with 6 to 12 carbon atoms. In some exemplary aralkyl groups, the aryl group is phenyl and the alkylene group has 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms (i.e., the structure of the aralkyl is alkylene-phenyl where an alkylene is bonded to a phenyl group).

[0172] In some polydiorganosiloxane groups, at least 50 percent of the R1groups are methyl. For example, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 95 percent, at least 98 percent, at least 99 percent, or all the R1groups can be methyl. The remaining R1groups can be selected from an alkyl having at least two carbon atoms, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo.

[0173] Each subscript n in the polydiorganosiloxane Q1group is independently an integer of 1 to 1500. For example, subscript n can be an integer up to 1000, up to 500, up to 400, up to 300, up to 200, up to 100, up to 80, up to 60, up to 40, up to 20, or up to 10. The value of n is often at least 1 , at least 2, at least 3, at least 5, at least 10, at least 20, or at least 40. For example, subscript n can be in the range of 40 to 1500, 0 to 1000, 40 to 1000, 0 to 500, 1 to 500, 40 to 500, 1 to 400, 1 to 300, 1 to 200, 1 to 100, 1 to 80, 1 to 40, or 1 to 20.

[0174] Each Y1in formula (I) is independently an alkylene, aralkylene, or a combination thereof. Suitable alkylene groups typically have up to 10 carbon atoms, up to 8 carbon atoms, up to 6 carbon atoms, or up to 4 carbon atoms. Exemplary alkylene groups include methylene, ethylene, propylene and butylene. Suitable aralkylene groups usually have an arylene group with 6 to 12 carbon atoms bonded to an alkylene group with 1 to 10 carbon atoms. In some exemplary aralkylene groups, the arylene portion is phenylene. That is, the divalent aralkylene group is phenylene-alkylene where the phenylene is bonded to an alkylene having 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. As used herein for group Y1, "a combination thereof' refers to a combination of two or more groups selected from an alkylene and aralkylene group. A combination can be, for example, a single aralkylene bonded to a single alkylene (e.g., alkylene-arylene- alkylene). In one exemplary alkylene-arylene-alkylene combination, the arylene is phenylene and each alkylene has 1 to 10, 1 to 6, or 1 to 4 carbon atoms. In some specific compounds of formula (I), the group Y1is an alkylene such as, for example, propylene.

[0175] Each R3is a single bond or is a divalent group that is a carbonyl, carbonylimino, carbonyloxy, imino, oxy, alkylene, alkylene substituted with a hydroxyl group, aralkylene, or a combination thereof. Suitable alkylene, aralkylene, and combinations thereof are the same as defined in group Y1. 241049W001

[0176] 21

[0177] Each R4is hydrogen or an alkyl such as an alkyl having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms.

[0178] Q2is S, NR4, or O, especially NR4, or O, very especially O.

[0179] The silicone compound having at least two ethylenically unsaturated groups often has a weight average molecular weight in a range of 500 Daltons (Da) to 200,000 Da. The weight average molecular weight can be at least 750 Da, at least 1 ,000 Da, at least 2,000 Da, at least 5,000 Da, at least 10,000 Da, or at least 20,000 Da. The weight average molecular weight can be up to 175,000 Da, up to 150,000 Da, up to 125,000 Da, up to 100,000 Da, up to 75,000 Da, up to 70,000 Da, up to 60,000 Da, or up to 50,000 Da. In some embodiments, the molecular weight is in a range of 1 ,000 to 150,000 Da, in a range of 2,000 to 125,000 Da, in a range of 3,000 to 100,000 Da, in a range of 4,000 to 75,000 Da, or in a range of 5,000 to 70,000 Da.

[0180] The group Q1in formula (I) is preferably a polydiorganosiloxane group of formula

[0181] , wherein each R1is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxyl, or halo; the variable n is an integer in a range of 1 to 1500.

[0182] In a particularly preferred embodiment Q1is a polydimethylsiloxane group.

[0183] In a preferred embodiment the silicone compound is a compound of formula erein n is an integer ranging from 1 to 350.

[0184] Polydiorganosiloxanes with two terminal (meth)acryloyl groups are commercially available from Gelest, Inc. under the trade designations DMS-U21 ((3-acryloxy-2- hydroxypropoxypropyl) terminated polydimethylsiloxane with molecular weight in the 241049W001

[0185] 22 range of 600 to 900 Da), DMS-R11 (methacryloxypropyl terminated dimethylsiloxane with molecular weight of 900 to 1200 Da), DMS-R18 (methacryloxypropyl terminated dimethylsiloxane with molecular weight of 4,500 to 5,500 Da), DMS-R22 (methacryloxypropyl terminated dimethylsiloxane with molecular weight of about 10,000 Da), and DMS-R31 (methacryloxypropyl terminated dimethylsiloxane with molecular weight of about 25,000 Da).

[0186] In addition, polydiorganosiloxanes with at least two (meth)acryloyl groups are available from Evonik Corp. (Richmond, VA, USA) under the trade designations TEGO (e.g., TEGO RC 711 , RC 902, and RC 715, which are acrylated terminated silicones that have various molecular weights) and from Siltech Corporation, Toronto, Ontario (Canada) under the trade designation SILMER (e.g., SILMER® ACR D208, ACR Di-50, ACR Di-1508, ACR Di-2510, ACR Di-4515-O, ACR Di-10, OH ACR Di-10, OH ACR Di- 50, OH ACR Di-100, OH ACR Di-400, and OH ACR C50.

[0187] Silicone compounds having at least one functional group and at least one polymerizable group may also be used according to the invention. Examples are SILMER® OH ACR Di-10, OH ACR Di-50, OH ACR Di-100, OH ACR Di 400 and OH ACR C50.

[0188] Liquid crystal composition

[0189] The term “liquid-crystalline” is used in the context of the present invention for cholesteric, unless otherwise evident from the particular context.

[0190] The cholesteric liquid crystal composition preferably comprises

[0191] A.1 at least one achiral nematic polymerizable monomer;

[0192] B.1 at least one chiral polymerizable monomer;

[0193] C.1 at least one photoinitiator;

[0194] C.3 at least one solvent;

[0195] C.5 optionally at least one leveling agent; and

[0196] C.10 optionally at least one in-can stabilizer.

[0197] The nematic liquid crystal composition preferably comprises

[0198] - 10-50% by weight, preferably 20-40% by weight of component(s) A.1 and B.1 based on total weight of component(s) A.1 , B.1 and C.1 ;

[0199] - 50-90% by weight, preferably 60-80% of solvent(s) C.3 based on total weight of component(s) A.1 and C.3;

[0200] - 0.5-10% by weight, preferably 1-5% by weight of photoinitiator(s) C.1 based on total weight of component(s) A.1 ;

[0201] - 0.01-1% by weight, preferably 0.01 - 0.2% by weight of levelling agent(s) C.5 based on total weight of component(s) A.1 ; 241049W001

[0202] 23

[0203] - 0.01-1.0 % by weight, preferably 0.04-0.7 % by weight of in-can stabilizer(s) C.10 based on total weight of component(s) A.1.

[0204] In addition, the liquid crystalline composition may comprise one or more substances selected from the group consisting of:

[0205] C.2 reactive diluents which comprise photopolymerizable groups;

[0206] C.4 defoamers and deaerators;

[0207] C.6 thermally curing and / or radiatively curing auxiliaries;

[0208] C.7 substrate wetting aids;

[0209] C.8 wetting and dispersing aids;

[0210] C.9 hydrophobizing agents;

[0211] C.11 auxiliaries for improving scratch resistance; and optionally as component D: one or more substances selected from the group consisting of:

[0212] D.1 dyes; and

[0213] D.2 pigments;

[0214] - at least one component E which is in turn selected from light, heat and oxidation stabilizers; and

[0215] - at least one component F which is in turn selected from IR-absorbing compounds.

[0216] The additives of group (C.4) to (C.11) are described in more detail on pages 25 to 35 of WO2021 / 032518.

[0217] The light, heat and oxidation stabilizers are described in more detail on pages 35 to 39 of WO2021 / 032518.

[0218] In a preferred embodiment the liquid crystal composition comprises

[0219] A.1 at least one achiral nematic polymerizable monomer and

[0220] B.1 at least one chiral polymerizable monomer;

[0221] C.1 at least one photoinitiator, which is preferably an alpha-hydroxy ketone compound of formula (XI), wherein

[0222] R29 is hydrogen; 241049W001

[0223] 24 c is 2-10;

[0224] G1 and G2independently of one another are hydrogen or methyl;

[0225] R31 is hydroxy;

[0226] R32and R33 independently of each other are Ci-C6alkyl;

[0227] R34 is hydrogen;

[0228] R35 is hydrogen, or OR88;

[0229] R36 is hydrogen, Ci-Ci2alkyl which optionally is interrupted by one or more non- consecutive O-atoms and which uninterrupted or interrupted Ci-Ci2alkyl optionally is

[0230] R39 is Ci-Ci2alkylene which optionally is interrupted by one or more non-consecutive O;

[0231] C.3 at least one solvent;

[0232] C.5 optionally at least one leveling agent, and

[0233] C.10 optionally at least one in-can stabilizer.

[0234] Preferably, the photoinitiator (C.1) is an alpha-hydroxy ketone compound of formula (Xia), wherein 241049W001

[0235] 25

[0236] R3I is hydroxy;

[0237] R32 and R33 independently of each other

[0238] R34 is hydrogen;

[0239] R35 is hydrogen.

[0240] Achiral nematic polymerizable monomer (A.1)

[0241] Preferably, at least one achiral nematic polymerizable monomer of the composition (a.1) is polyfunctionally and especially difunctionally polymerizable. Such monomers are, for example, described in W005049703, WO, 97 / 00600, WO 2006 / 120220, W000551 10 and G. Challa et al., Makromol. Chem. 190 (1989) 3201-3215).

[0242] Preferred achiral nematic difunctionally polymerizable monomers correspond to the general formula I:

[0243] Z1-(Y1-A1)v-Y2-M-Y3-(A2-Y4)w-Z2(I), in which

[0244] Z1, Z2are identical or different reactive groups through which polymerization can be effected, or radicals which comprise such reactive groups, the reactive groups preferably being selected from C=C double bonds, C=C triple bonds, oxirane, thiirane, azirane, cyanate, thiocyanate, isocyanate, carboxylic acid, hydroxyl or amino groups, and preferably from C=C double bonds (these may, for example, 241049W001

[0245] 26 be -CH=CH2or -C(CH3)=CH2or else -CH=CH(CH3), preference being given to the first two mentioned);

[0246] Y1, Y2, Y3, Y4are each independently a chemical bond, -O-, -S-, -CO-O-, -O-CO-, -O- CO-O-, -CO-S-, -S-CO-, -CO-N(Ra)-, -N(R3)-CO-, -N(Ra)-CO-O-, -O-CO-N(Ra)-, - N(Ra)-CO-N(Ra)-, -CH2-O-, -O-CH2-, preferably -CO-O-, -O-CO- or -O-CO-O-, where Rais hydrogen or Ci-C4-alkyl;

[0247] A1, A2are identical or different spacers which are selected from linear C2-C30.alkylene groups, preferably C2-Ci2-alkylene groups, which may be interrupted by -CO-O-, oxygen, sulfur and / or optionally monosubstituted nitrogen, where these interrupting groups must not be adjacent; where suitable amine substituents comprise Ci-C4-alkyl groups, where the alkylene chains may be substituted by fluorine, chlorine, bromine, cyano, methyl or ethyl; and where A1and A2are more preferably -(CH2)n- where n = from 2 to 6; v and w are each independently 0, 1 or 2;

[0248] M is a mesogenic group, preferably a mesogenic group of the general formula II:

[0249] (T1-Y5)y-T2(II), in which each T1is independently a divalent alicyclic, saturated or partially unsaturated heterocyclic, aromatic or heteroaromatic radical;

[0250] T2is independently as defined for T1;

[0251] Y5represents identical or different bridging members -CO-O-, -O-CO-, -CH2-O-, -O- CH2-, -CO-S-, -S-CO-, -CH2-S-, -S-CH2, -CH=N-, -N=CH-, -CH=N-N=CH-, -C=C-, -CH=CH-, -C(CH3)=CH2, -CH=CH(CH3)- or a direct bond and is preferably -CO- O- or -O-CO-, and y is an integer from 0 to 3, preferably 0, 1 or 2, in particular 1 or 2 and especially 2.

[0252] T2is preferably an aromatic radical and more preferably a phenyl radical. T2is especially a radical of the formula , in which

[0253] Rbis fluorine, chlorine, bromine, Ci-C20-alkyl, C-i-C-io-alkoxy, C-i-C-io-alkylcarbonyl, C-i-C-io-alkylcarbonyloxy, C-i-C-io-alkoxycarbonyl, hydroxyl, nitro, CHO or CN, preferably chlorine, bromine, Ci-C4-alkyl or Ci-C4-alkoxycarbonyl, and especially methyl or methoxycarbonyl; and x is 0, 1 , 2, 3 or 4, preferably 0, 1 or 2, more preferably 0 or 1 and especially 1 .

[0254] Each T1is independently preferably an aromatic radical, more preferably phenyl or naphthyl and especially 1 ,4-bonded phenyl or 2,6-bonded naphthyl. Y5is preferably - CO-O- or -O-CO-. y is preferably 2.

[0255] Particularly preferred mesogenic groups M have the following structures: 241049W001 in which Rband x each have one of the general or preferred definitions specified above, where Rbis especially methyl and x is 1 , or in which Rband x have one of the general or preferred definitions specified above, where Rbis especially methoxycarbonyl and x is 1 .

[0256] In a particularly preferred embodiment the liquid crystal composition comprises as component A.1 : one or more compounds of the general formula lb

[0257] (lb), especially one or more compounds (1 .a), (1 .b), (1 .c), (1 .d), (1 .e), or (1 .f); in which the variables are defined as follows:

[0258] Z1, Z2are each independently

[0259] A1, A2are each independently spacers having 4 to 8 carbon atoms,

[0260] Y1, Y4are each independently a single chemical bond, oxygen, -CO-, -O-CO- or

[0261] -CO-O-,

[0262] Rbis hydrogen, Ci-C6-alkyl or CO-O-Ci-C6-alkyl, as component A.1 : one or more compounds of the general formula la

[0263] (la), one or more compounds of the general formula Ic 241049W001

[0264] 28

[0265] (lc), in which the variables are defined as follows: Z1, Z2are each independently

[0266] A1’, A2‘are each independently spacers having 4 to 8 carbon atoms, which is optionally interrupted by -CO-O-;

[0267] Y1, Y4are each independently a single chemical bond, oxygen, -CO-, -O-CO- or - CO-O-,

[0268] Rbis hydrogen, Ci-C6-alkyl or CO-O-Ci-C6-alkyl.

[0269] In a particularly preferred embodiment, the achiral nematic difunctionally polymerizable monomers are selected from compounds of the following formulae I. a, l.b and l.c: 241049W001

[0270] 29 and mixtures thereof.

[0271] However, the composition (a.1) may also comprise a monofunctionally polymerizable achiral nematic monomer. This preferably has the general formula (Illa) and / or (lllb):

[0272] A3-Y2-M-Y3-(A2-Y4)W-Z2(Illa) Z1-(Y1-A1)v-Y2-M-Y3-A3(lllb), in which

[0273] Z1, A1, Y1, Y2, Y3, Y4, v, w and M are each independently as defined generally or preferably for formula (I); and

[0274] A3is a linear C-i-C3o.alkyl group, preferably a linear Ci-Ci2-alkyl group, which may be interrupted by oxygen, sulfur and / or optionally monosubstituted nitrogen, where these interrupting groups must not be adjacent; where suitable amine substituents comprise Ci-C4-alkyl groups, where the alkyl group may be substituted by fluorine, chlorine, bromine, cyano, methyl or ethyl, or is CN or -N=C=S-.

[0275] A3is preferably linear C2-C8-alkyl or CN and especially linear C4-C8-alkyl or CN. Y1, Y2, Y3, Y4and Y5are each independently preferably -O-CO-, -CO-O-, -O-CO-O- or a C-C- triple bond. Z1is preferably a C-C-double bond (preferably -CH=CH2or -C(CH3)=CH2). M is preferably a mesogenic group of the general formula II. T1and T2are preferably each independently an aromatic group, more preferably phenyl or naphthyl which may bear 0, 1 , 2, 3 or 4 Rbradicals, where Rbhas one of the general or preferred definitions specified above, especially 1 ,4-bonded phenyl or 2,6-bonded naphthyl which may bear 0, 1 , 2, 3 or 4 Rbradicals, where Rbhas one of the general or preferred definitions specified above, and especially unsubstituted 1 ,4-bonded phenyl or unsubstituted 2,6- bonded naphthyl, y is preferably 0 or 1 .

[0276] Particularly preferred monofunctionally polymerizable achiral nematic monomers are selected from the following structures: 241049W001 241049W001

[0277] 31

[0278] The at least one achiral nematic polymerizable monomer of the composition (a.1) comprises preferably

[0279] (i) at least one difunctionally polymerizable achiral nematic monomer of the formula (I), preferably one or two difunctionally polymerizable achiral nematic monomers of the formula (I); and

[0280] (ii) optionally at least one monofunctionally polymerizable achiral nematic monomer of the formula (Illa) and / or (lllb).

[0281] When the composition (a.1) comprises one or more monofunctionally polymerizable monomers, they are preferably present in the composition in a total amount of not more than 50% by weight, more preferably of not more than 25% by weight, even more preferably of not more than 15% by weight based on the total weight of the poly- and monofunctionally polymerizable achiral nematic monomers.

[0282] In a specific embodiment, the composition (a.1) does not comprise any monofunctionally polymerizable achiral nematic monomers, but rather only at least one, preferably one or two, polyfunctionally, especially difunctionally, polymerizable achiral nematic monomer(s).

[0283] Chiral Polymerizable Monomer (B.1)

[0284] The chiral polymerizable monomer of the composition (B.1) is, for example, described in EP1273585, W00294805 and EP0750029. Reference is made to page 14 to 19 of WO2021 / 032518.

[0285] Preferably, the liquid crystal composition comprises as component B.1 one or more substances selected from the group consisting of:

[0286] (I .a), 241049W001

[0287] 32

[0288] Photoinitiator (C.1) A photoinitiator for the purposes of this specification is a compound which can be cleaved into at least one radical by electromagnetic radiation, preferably by UV radiation, visible light or IR radiation, more preferably by UV radiation or visible light, and very preferably by UV radiation. Component (C.1) may comprise one or more than one - for example, 1 to 3, preferably 1 to 2, and more preferably precisely one - group which is active as a photoinitiator,

[0289] The photoinitiator (C.1) is preferably an alpha-hydroxy ketone compound of formula 241049W001

[0290] 33

[0291] R3I is hydroxy; R32and R33 independently of each other are Ci-Cealkyl, especially methyl;

[0292] R34 is hydrogen;

[0293] R35 is hydrogen.

[0294] The at present most preferred photinitiators are selected from

[0295] In principle, the alpha-hydroxy ketone compounds of formula (XI) can be used in admixture with other photoinitiators, which do not represent CMR compounds and do not negatively affect the thermal stability and resistance against chemicals and solvents of the liquid crystal films obtainable from the liquid crystal compositions of the present application. Examples of such photo initiators are oxime ester compounds of the formula wherein z is O or l ; 241049W001

[0296] 34

[0297] R70 is hydrogen, C3-C8cycloalkyl; Ci-Ci2alkyl which is unsubstituted or substituted by one or more halogen, phenyl or by CN; or R70 is C2-C5alkenyl; phenyl which is unsubstituted or substituted by one or more Ci-C6alkyl, halogen, CN, OR73, SR74 or by NR75R76; or R70 is Ci-C8alkoxy, benzyloxy; or phenoxy which is unsubstituted or substituted by one or more Ci-C6alkyl or by halogen;

[0298] R71 is phenyl, naphthyl, benzoyl or naphthoyl, each of which is substituted by one or more halogen, Ci-Ci2alkyl, C3-C8cycloalkyl, benzyl, phenoxycarbonyl, C2-Ci2alkoxycar- bonyl, OR73, SR74, SOR74, SO2R74 or by NR75R76, wherein the substituents OR73, SR74 and NR75R76 optionally form 5- or 6-membered rings via the radicals R73, R74, R75 and / or R76 with further substituents on the phenyl or naphthyl ring; or each of which is substituted by phenyl or by phenyl which is substituted by one or more OR73, SR74 or by NR75R66; or R71 is thioxanthyl,

[0299] R72is hydrogen; unsubstituted C-i-C2oalkyl or C-i-C2oalkyl which is substituted by one or more halogen, OR73, SR74, C3-C8cycloalkyl or by phenyl; or is C3-C8cycloalkyl; or is phenyl which is unsubstituted or substituted by one or more Ci-C6alkyl, phenyl, halogen, OR73, SR74 or by NR75R76; or is C2-C20alkanoyl or benzoyl which is unsubstituted or substituted by one or more Ci-C6alkyl, phenyl, OR73, SR74 or by NR75R76; or is C2- Ci2alkoxycarbonyl, phenoxycarbonyl, CN, CONR75R76, NO2, Ci-C4haloalkyl, S(O)y-Ci- C6alkyl, or S(O)y-phenyl, y is 1 or 2;

[0300] Y2is a direct bondor no bond;

[0301] R73and R74 independently of one another are hydrogen, Ci-C20alkyl, C2-Ci2alkenyl, C3- C8cycloalkyl, C3-C8cycloalkyl which is interrupted by one or more, preferably 2, O, phenyl-Ci-C3alkyl; or are Ci-C8alkyl which is substituted by OH, SH, CN, Ci-C8alkoxy, Ci-C8alkanoyl, C3-C8cycloalkyl, by C3-C8cycloalkyl which is interrupted by one or more O, or which Ci-C8alkyl is substituted by benzoyl which is unsubstituted or substituted by one or more Ci-C6alkyl, halogen, OH, Ci-C4alkoxy or by Ci-C4alkylsulfanyl; or are phenyl or naphthyl, each of which is unsubstituted or substituted by halogen, Ci-Ci2alkyl, C1- Ci2alkoxy, phenyl-Ci-C3alkyloxy, phenoxy, Ci-Ci2alkylsulfanyl, phenylsulfanyl, N(Ci-

[0302] Ci2alkyl)2, diphenylamino

[0303] R75 and R76 independently of each other are hydrogen, Ci-C20alkyl, C2-C4hydroxyalkyl, C2-C-ioalkoxyalkyl, C2-C5alkenyl, C3-C8cycloalkyl, phenyl-Ci-C3alkyl, Ci-C8alkanoyl, C3- Ci2alkenoyl, benzoyl; or are phenyl or naphthyl, each of which is unsubstituted or substituted by Ci-Ci2alkyl, benzoyl or by Ci-Ci2alkoxy; or R75 and R78together are C2- 241049W001

[0304] 35

[0305] C6alkylene optionally interrupted by O or NR73 and optionally are substituted by hydroxyl, Ci-C4alkoxy, C2-C4alkanoyloxy or by benzoyloxy;

[0306] R77 is Ci-Ci2alkyl, thienyl or phenyl which is unsubstituted or substituted by C1- Ci2alkyl, OR73, morpholino or by N-carbazolyl.

[0307] Specific examples are 1 ,2-octanedione 1-[4-(phenylthio)phenyl]-2-(0-benzoyloxime)

[0308] (Irgacure® OXE01), ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(0- acetyloxime) (Irgacure® OXE02), 9H-thioxanthene-2-carboxaldehyde 9-oxo-2-(0- acetyloxime), ethanone 1-[9-ethyl-6-(4morpholinobenzoyl)-9H-carbazol-3-yl]-1-(0- acetyloxime), ethanone 1 -[9-ethyl-6-(2-methyl-4-(2-(1 ,3-dioxo-2-dimethyl-cyclopent-5- yl)ethoxy)-benzoyl)-9H-carbazol-3-yl]-1-(0-acetyloxime) (Adeka N-1919), ethanone 1- [9-ethyl-6-nitro-9H-carbazol-3-yl]-1-[2-methyl-4-(1-methyl-2-methoxy)ethoxy)phenyl]-1- (O-acetyloxime) (Adeka NCI831), etc.

[0309] The photoinitiators are used typically in a proportion of from about 0.1 to 7.0% by weight based on the total weight of the liquid-crystalline mixture. Especially when the hardening is performed under inert gas atmosphere, it is possible to use significantly smaller amounts of photoinitiators. In this case, the photoinitiators are used in a proportion of from about 0.1 to 1 .0% by weight, preferably from 0.2 to 0.6% by weight, based on the total weight of the liquid-crystalline mixture.

[0310] Solvent (C.3)

[0311] Group (C.3) of the solvents includes, for example, Ci-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol, butanol, isobutanol, sec-butanol, tertbutanol, and the C5-Ci2-alcohols n-pentanol, n-hexanol, n-heptanol, n-octanol, n- nonanol, n-decanol, n-undecanol and n-dodecanol and isomers thereof, glycols, for example 1 ,2-ethylene glycol, 1 ,2 or 1 ,3-propylene glycol, 1 ,2 , 2,3 or 1 ,4-butylene glycol, di or triethylene glycol or di or tripropylene glycol, ethers, for example openchain ethers such as methyl tert-butyl ether, 1 ,2-ethylene glycol monomethyl or dimethyl ether, 1 ,2-ethylene glycol monoethyl or diethyl ether, 3-methoxypropanol or 3- isopropoxypropanol, or cyclic ethers such as tetrahydrofuran or dioxane, open-chain ketones, for example acetone, methyl ethyl ketone, methyl isobutyl ketone or diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), cyclic ketones such as cyclopentanone, or cyclohexanone, Ci-C5-alkyl esters, for example methyl acetate, ethyl acetate, propyl acetate, butyl acetate or amyl acetate, Ci-C4-alkoxy-Ci-C4-alkyl esters such as 1- methoxyprop-2-yl acetate, carboxamides such as dimethylformamide and dimethylacetamide, N-heterocycles such as N-methylpyrrolidone, aliphatic or aromatic hydrocarbons, for example pentane, hexane, heptane, octane, isooctane, petroleum ether, toluene, xylene, ethylbenzene, tetralin, decalin, dimethylnaphthalene, white spirit, Shellsol® or Solvesso®, mineral oils, for example gasoline, kerosene, diesel oil or heating oil, but also natural oils, for example olive oil, soybean oil, rapeseed oil, 241049W001

[0312] 36 linseed oil or sunflower oil. As a matter of course, mixtures of these solvents are also useful for use in the inventive mixtures.

[0313] Preferably, the liquid crystal composition comprises as component C.3 one, or more solvents which are selected from the group consisting of Ci-C4-alkoxy-Ci-C4-alkyl esters, carboxamides, open-chain ethers, open-chain and cyclic ketones, alcohols, lactones and aromatics and mixtures thereof.

[0314] Lubricants and leveling agents (C.5)

[0315] The group (C.5) of the lubricants and leveling agents includes, for example, silicon-free but also silicon-containing polymers, for example polyacrylates or modified low molecular weight polydialkylsiloxanes. The modification consists in replacing some of the alkyl groups with a wide variety of organic radicals. These organic radicals are, for example, polyethers, polyesters or else long-chain alkyl radicals, the former finding most frequent use.

[0316] The polyether radicals of the correspondingly modified polysiloxanes are typically formed by means of ethylene oxide and / or propylene oxide units. The higher the proportion of these alkylene oxide units is in the modified polysiloxane, the more hydrophilic is generally the resulting product.

[0317] Such auxiliaries are obtainable commercially, for example, from Tego as TEGO® Glide 100, TEGO® Glide ZG 400, TEGO® Glide 406, TEGO® Glide 410, TEGO® Glide 411 , TEGO® Glide 415, TEGO® Glide 420, TEGO® Glide 435, TEGO® Glide 440, TEGO® Glide 450, TEGO® Glide A 115, TEGO® Glide B 1484 (also usable as a defoamer and deaerating agent), TEGO® Flow ATF, TEGO® Flow ATF2, TEGO® Flow 300, TEGO® Flow 460, TEGO® Flow 425 and TEGO® Flow ZFS 460. The radiation-curable lubricants and leveling agents used, which additionally also serve to improve scratch resistance, can be the products TEGO® Rad 2100, TEGO® Rad 2200, TEGO® Rad 2300, TEGO® Rad 2500, TEGO® Rad 2600, TEGO® Rad 2700 and TEGO® Twin 4000, likewise obtainable from Tego. Such auxiliaries are obtainable from BYK, for example as BYK®-300, BYK®-306, BYK®-307, BYK®-310, BYK®-320, BYK®-322, BYK®-331 , BYK®-333, BYK®-337, BYK®-341 , Byk® 354, Byk® 361 N, BYK®-378 and BYK®-388.

[0318] The auxiliaries of group (C.5) are typically used in a proportion of from about 0.005 to 1 .0% by weight, preferably from about 0.01 to 0.2% by weight, based on the total weight of the liquid-crystalline mixture.

[0319] Component (C.10) 241049W001

[0320] 37

[0321] Preferably, the liquid crystal composition comprises as component C.10 one, or more compounds selected from compounds of formula , wherein

[0322] R21and R22independently of each other are Ci-Ci8alkyl, C5-Ci2cycloalkyl, C7-C15- phenylalkyl, optionally substituted C6-Ci0aryl;

[0323] R23and R24independently of each other are H, optionally substituted C6-Cio-aryl, 2-,3- ,4-pyridyl, 2-,3-furyl or thienyl, COOH, COOR25, CONH2, CONHR25, CONR25R26, — CN, — COR25, — OCOR25, — OPO(OR25)2, wherein R25and R26are independently of each other Ci-C8alkyl, or phenyl; tris(2,4-di-tert-butylphenyl) phosphite, tris(nonylphenyl) phosphite,

[0324] 241049W001

[0325] 38

[0326] In addition, the present invention is directed to a security element, comprising a substrate suitable for aligning liquid crystals; a pattern deposited on the substrate; and a layer of liquid crystals disposed on at least part of the substrate and at least partially covering the pattern, obtainable by the process defined above.

[0327] The security element can comprise one, or more further layers, which are selected from release layers, primer layers, glue layers, substrate layers, black layers, white layers, metallic layers, plasmonic layers, embossed layers with diffractive gratings, micromirrors, lenses, magnetic layers, fluorescent layers, interference layers, colored layers, IR-absorbing layers, IR-transparent layers and conductive layers.

[0328] The layers might be fully, or partially printed on the security element.

[0329] The security element can comprise at least one additional security structure, notably chosen from among the first, second or third level security structure. It can involve: patterns appearing in transmitted light and formed by metallization and / or demetallization, colorants, luminescent pigments, interferential pigments, in printed form or mixed with at least one constituent layer of the security element, compounds, colorants and / or photochromic or thermochromic pigments, notably in printed form or mixed with at least one constituent layer of the security element, ultraviolet (UV) absorber, notably in coated form or mixed with at least one constituent layer of the security element, interferential multilayer structure, a refractive, birefringent or polarizing layer, a diffraction structure, 241049W001

[0330] 39 means producing a "moire effect" or a parallax effect, such an effect being for example able to reveal a pattern produced by the superposition of two security means, for example by the convergence of lines of two security means, notably by folding, a color filter, an automatically-readable security measure, having specific and measurable characteristics, notably of luminescence (for example fluorescence, phosphorescence), of light absorption (for example ultraviolet, visible or infrared), of Raman activity, of magnetism, of microwave interaction, of interaction with X-rays or of electrical conductivity.

[0331] In addition, the present invention is directed to a security document, comprising the security element according to the present invention as a laminate onto the document or embedded as a (windowed) thread into the document or as a window embedded on the document.

[0332] The security document may be a banknote, tax stamp, ID-card, voucher, entrance ticket, or label.

[0333] Various features and aspects of the present invention are illustrated further in the examples that follow. While these examples are presented to show one skilled in the art how to operate within the scope of this invention, they are not to serve as a limitation on the scope of the invention where such scope is only defined in the claims. Unless otherwise indicated in the following examples and elsewhere in the specification and claims, all parts and percentages are by weight, temperatures are in degrees centigrade and pressures are at or near atmospheric.

[0334] Examples

[0335] Application example 1

[0336] Dewetting varnish preparation: 1 g of Silmer® NH Di-50 or Silmer SH JO, commercially available from Siltech Corporation, was added to 99 g of UV-curable varnish, composition of which is shown in Table 1 , and thoroughly mixed.

[0337] Table 1 . Exemplary composition of UV-curable varnish. 241049W001

[0338] 40

[0339] The obtained dewetting varnish was applied with a wired handcoater #2 onto Melinex® 506 substrate. A stamp with an engraved pattern of rainbow shape was pressed against this wet layer and then pressed against a piece of Lumirror® 4001 substrate (biaxially oriented polyester film, 50pm thickness). After removing the stamp from the substrate, leaving a pattern of dewetting varnish on it, the pattern was UV-cured with Technigraf UV belt dryer (undoped mercury lamp, 9m / min, two passes) to solidify the pattern. A liquid crystal formulation was prepared according to the following recipe:

[0340] LC 1 : compound I. a

[0341] Dopant: compound IV.a 241049W001

[0342] 41

[0343] This formulation was applied to the Lumirror® substrate with the solidified de-wetting pattern on it using film applicator ZAA2300 at 20mm / s rate, with a profile rod handcoater 16pm No.7 ACC378.016. After application, the layer of liquid crystals was dried in an oven at 100°C for 60s and then UV-cured two times with the belt dryer with the same settings as de-wetting varnish (theoretical dry liquid crystal layer thickness 6.7pm).

[0344] Observations: the liquid crystal layer was practically completely de-wetted from the dewetting pattern, forming areas with a higher liquid crystal layer thickness between the lines of de-wetting pattern, thus creating a surface relief structure of liquid crystals (Fig. 2).

[0345] The rainbow pattern of liquid crystals appears more intensely coloured than the flat liquid crystal coating at the same observation angle. In addition, it shows a different colour shift behaviour, as compared to flat liquid crystal layer.

[0346] Application Example 2

[0347] Dewetting varnish preparation: 1 g of Silmer®ACR Di-10, commercially available from Siltech Corporation, was added to 99 g of an UV-curable varnish, the composition of which is shown in table 1 , and thoroughly mixed.

[0348] The obtained dewetting varnish was applied with a wired handcoater #2 onto Melinex® 506 substrate. A stamp with an engraved pattern of rainbow shape was pressed against this wet layer and then pressed against a piece of Lumirror® 4001 substrate (biaxially oriented polyester film, 50pm thickness). After removing the stamp from the substrate, leaving a pattern of dewetting varnish on it, the pattern was UV-cured with Technigraf UV belt dryer (undoped mercury lamp, 9m / min, two passes) to solidify the pattern.

[0349] The liquid crystal formulation used in application example 1 was applied to the Lumirror substrate with the solidified de-wetting pattern on it using film applicator ZAA2300 at 20mm / s rate, with a profile rod handcoater 16pm No.7 ACC378.016. After application, the layer of liquid crystals was dried in an oven at 100°C for 60s and then UV-cured two times with the belt dryer with the same settings as de-wetting varnish (theoretical dry liquid crystal layer thickness 6.7pm). 241049W001

[0350] 42

[0351] Observations: the liquid crystal layer was practically completely de-wetted from the dewetting pattern, forming areas with a higher liquid crystal layer thickness between the lines of de-wetting pattern, thus creating a surface relief structure of liquid crystals. Reference is made to Fig. 3.

[0352] The rainbow pattern of liquid crystals appears more intensely coloured than the flat liquid crystal coating at the same observation angle. In addition, it shows a different colour shift behaviour, as compared to flat liquid crystal layer.

Claims

1. 241049W00143Claims1 . A process for the production of a security element, which comprises an optical structure with relief effect, comprising a) providing a substrate, especially a flexible suitable for aligning liquid crystals; b) depositing a curable composition, or a solvent-based composition, comprising a polymer, which is insoluble in the liquid crystal composition from step e) after evaporation of solvent, in a pattern on the substrate; c) optionally evaporating the solvent of the curable composition by applying IR- radiation and / or thermal drying; or evaporating the solvent of the solvent-based composition by applying IR-radiation and / or thermal drying; d) curing the pattern of the curable composition deposited in step b) by means of UV / VIS radiation or electron beam, wherein the curable composition and the solvent-based composition comprise at least one silicone compound having at least one functional group; preferably having at least two functional groups; and / or at least one silicone compound having at least one polymerizable group, especially having at least one ethylenically unsaturated group; preferably having at least two polymerizable groups, especially having at least two ethylenically unsaturated groups; e) applying a liquid crystal composition on at least a part of the substrate and on at least part of the pattern; f) optionally evaporating the solvent of the liquid crystal composition by applying IR-radiation and / or thermal drying; g) curing the liquid crystal composition deposited in step e) by means of UV / VIS radiation or electron beam; wherein the liquid crystal composition is practically completely de-wetted from the de-wetting pattern obtained in step d).

2. The process according to claim 1 , wherein the silicone compound having at least one functional group is a compound of formula(A), wherein-Q- represents a C-i-C2oalkylene group, eventually in which one or more -CH2- are replaced by -O-, or represents a C6-C22arylene group,W represents -OH or -NHR', with R' representing -H, a Ci-CiOalkyl group, or a C6- C22aryl group,-R111represents - independently in each occurrence - a Ci-C20alkyl group, which may be interrupted by one or more oxygen atoms and / or eventually substituted by one or more -SH, -NH2, -F, -OH, -CH3and / or -Cl, and a is an integer ranging from 30 to 1000.241049W001443. The process according to claim 1 , or 2, wherein -R111represents a Ci-C6alkyl group eventually substituted by one or more -F and / or -Cl, -W represents -NHR' with -R' representing -H, a Ci-CiOalkyl group, or a C6-Ci8aryl group, and -Q- represents a C2-Ci0alkylene group, eventually in which one or more -CH2- are replaced by -O-.

4. The process according to any of claims 1 to 3, wherein R111represents a methyl group, -W represents -NH2, -Q- represents a C2-C6alkylene group, and a is an integer ranging from 30 to 150.

5. The process according to claim 1 , wherein the silicone compound having at least one polymerizable group is a compound of formula H2=CR2-R3-Q2-Y1-Q1-Y1-Q2- R3-CR2=CH2(I), whereinQ1is a polydiorganosiloxane group;Q2is S, NR4, or O, especially NR4, or O, very especially O, each R2is a hydrogen or methyl; each R3is a single bond or is a divalent group selected from a carbonyl, carbonylimino, carbonyloxy, imino, oxy, alkylene, alkylene substituted with a hydroxyl group, aralkylene, and a combination thereof, and each R4is hydrogen or an alkyl, and each Y1is independently an alkylene, aralkylene, or a combination thereof.

6. The process according to claim 1 , or 5, wherein the group Q1in formula (I) is a polydiorganosiloxane group of formula , whereineach R1is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxyl, or halo; the variable n is an integer in a range of 0 to 1500.

7. The process according to any of claims 1 , 5 or 6, wherein the silicone compound is a compound of formula241049W00145(lb), or a mixture thereof, wherein n is an integer ranging from 1 to 350.

8. The process according to any of claims 1 to 7, wherein the liquid crystal composition comprisesA.1 at least one achiral nematic polymerizable monomer andB.1 at least one chiral polymerizable monomer;C.1 at least one photoinitiator, which is preferably an alpha-hydroxy ketoneR29 is hydrogen;c is 2-10;Gi and G2independently of one another are hydrogen or methyl;R3I is hydroxy;R32and R33independently of each other are Ci-C6alkyl;R34is hydrogen;241049W00146R35is hydrogen, or OR36;R36is hydrogen, Ci-Ci2alkyl which optionally is interrupted by one or more non- consecutive O-atoms and which uninterrupted or interrupted Ci-Ci2alkyl optionallyR39is Ci-Ci2alkylene which optionally is interrupted by one or more non- consecutive O;C.3 at least one solvent;C.5 optionally at least one leveling agent, andC.10 optionally at least one in-can stabilizer.

9. The process according to claim 8, wherein the photoinitiator (C.1) is an alphahydroxy ketone compound of formulaR3I is hydroxy;R32and R33independently of each other are Ci-C6alkyl, especially methyl;R34is hydrogen;R35is hydrogen, preferably the photoinitiator (C.1) is selected from241049W00147and mixtures thereof.

10. The process according to claims 8, or 9, wherein the liquid crystal composition comprises as component A.1 one or more compounds selected from compounds of the general formula lbin which the variables are defined as follows:A1, A2are each independently spacers having 4 to 8 carbon atoms,Y1, Y4are each independently a single chemical bond, oxygen, -CO-, -O-CO- or -CO-O-,Rbis hydrogen, Ci-C6-alkyl or CO-O-Ci-C6-alkyl,Rcis hydrogen, or Ci-C6-alkyl; and compounds of the general formula la(la), in which the variables are defined as follows:Z1, Z2are each independentlyA1’, A2‘are each independently spacers having 4 to 8 carbon atoms,241049W00148Y1, Y4are each independently a single chemical bond, oxygen, -CO-, -O-CO- or -CO-O-,Rbis hydrogen, Ci-C6-alkyl or CO-O-Ci-C6-alkyl.

11. The process according to any of claims 8 to 10, wherein the liquid crystal composition comprises as component B.1 one or more substances selected from the group consisting of:241049W0014912. The process according to any of claims 8 to 1 1 , wherein the liquid crystal composition comprises as component C.3 one, or more solvents which are selected from the group consisting of Ci-C4-alkoxy-Ci-C4-alkyl esters, carboxamides, open-chain ethers, open-chain and cyclic ketones, alcohols, lactones and aromatics and mixtures thereof.

13. The process according to any of claims 8 to 12, wherein the liquid crystal composition comprises as component C.10 one, or more compounds selected from compounds of formula, whereinR21and R22independently of each other are Ci-Ci8alkyl, C5-Ci2cycloalkyl, C7-C15- phenylalkyl, optionally substituted C6-Ci0aryl;R23and R24independently of each other are H, optionally substituted C6-Cio-aryl, 2-,3-,4-pyridyl, 2-,3-furyl or thienyl, COOH, COOR25, CONH2, CONHR25, CONR25R26, — CN, —COR25, — OCOR25, — OPO(OR25)2, wherein R25and R26are independently of each other Ci-C8alkyl, or phenyl; tris(2,4-di-tert-butylphenyl) phosphite, tris(nonylphenyl) phosphite,241049W00150butyl hydroxytoluene (BHT;14. A security element obtained by the process according to any of claims 1 to 13, comprising a substrate suitable for aligning liquid crystals; a pattern deposited on the substrate; and a layer of liquid crystals (i) disposed on at least part of the substrate, a layer of liquid crystals (ii) disposed next to the pattern having a higher thickness than layer (i), and the layer of liquid crystals is practically completely de-wetted from the pattern.

15. The security element according to claim 14, comprising one, or more further layers, which are selected from release layers, primer layers, glue layers, substrate layers, black layers, white layers, metallic layers, plasmonic layers, embossed layers with diffractive gratings, micromirrors, lenses, magnetic layers, fluorescent layers, interference layers, colored layers, IR-absorbing layers, IR- transparent layers and conductive layers.

16. The security element according to claim 14, or 15, wherein the layers might be fully, or partially printed on the security element.

17. A security document, comprising the security element according to any of claims14 to 16 as a laminate onto the document or embedded as a (windowed) thread into the document or as a window embedded on the document.

18. The security document according to claim 17, which is a banknote, tax stamp, ID- card, voucher, entrance ticket, or label.

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