Printing process

Abstract

The invention provides a novel security feature and a method for making it.

Description

[0001] PRINTING PROCESS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the field of security printing processes, as well as security features produced using such security printing processes.

[0004] BACKGROUND OF THE INVENTION

[0005] With the constantly improving quality of color photocopies and printing, and in an attempt to protect security documents and articles such as banknotes, value documents or cards, transportation tickets or cards, tax banderols, and product labels that have no reproduceable effects against counterfeiting, falsifying or illegal reproduction, it has been the conventional practice to incorporate various security elements in these documents and articles.

[0006] Security features can generally be classified into “covert” security features on the one hand, and “overt” security features on the other hand. The protection provided by covert security features relies on the concept that such features are difficult to detect, typically requiring specialized equipment and knowledge for detection, whereas “overt” security features rely on the concept of being easily detectable with the unaided human senses, e.g. such features may be visible and / or detectable via the tactile senses while still being difficult to produce and / or to copy. However, the effectiveness of overt security features depends to a great extent on their eye-catching effect and their easy recognition as a security feature, because most users, and particularly those having no prior knowledge of the security features of a document or article secured therewith, will only then actually perform a security check based on said security feature if they have actual knowledge of their existence and nature.

[0007] Optically variable inks provide first-line recognizability not only by a person, but also facilitate machine- readability. One example of optically variable inks is the class of compounds called cholesteric liquid crystal polymers. When illuminated with light, the cholesteric liquid crystal structure reflects light of a certain color which depends on the material in question and varies upon changing the viewing angle, for example by tilting the security feature. The cholesteric liquid crystal material itself is colorless and the observed color is the result of a physical reflection effect of the cholesteric helical structure that is adopted by the liquid crystal precursor composition at a given temperature. See, e.g., J.L. Fergason, Molecular Crystals, Vol. 1, pp. 293-307 (1966).

[0008] Materials having a liquid crystal structure with a chiral phase, also known as cholesteric liquid crystal materials, are known and used as optically variable security features. Cholesteric liquid crystal polymers show a molecular order in the form of a helical superstructure perpendicular to the longitudinal axes of its molecules. The helical superstructure provides for a periodic refractive index modulation throughout the liquid crystal material, which in turn results in a selective transmission I reflection of determined wavelengths of light (interference filter effect). Cholesteric liquid crystal polymers can be obtained by subjecting one or more polymerizable nematic monomers and one or more chiral monomers to alignment and orientation. The particular situation of the helical molecular arrangement leads to cholesteric liquid crystal materials exhibiting the property of reflecting a circularly polarized light component within a determined wavelength range, wherein said circularly polarized light may be left- handed or right-handed, depending on the sense of rotation of the molecular helices. The range of wavelengths reflected by a cholesteric liquid crystal polymer is determined by the geometry of its periodic refractive index modulation, i.e. the pitch of the molecular helices, as known to the skilled man. The pitch (i.e. the distance over which a full rotation of 360° of the helical arrangement is completed) can be tuned in particular by varying selectable factors including the temperature and solvents concentration, by changing the nature of the chiral component(s) and the ratio of nematic and chiral compounds. The pitch of the material can finally be frozen by a cross-linking (polymerization) reaction, such that the color of the resulting cholesteric liquid crystal polymer is independent of external factors such as temperature.

[0009] United States patent no. 10,611 ,919 describes security features made from cholesteric liquid crystal compositions in which the liquid crystal monomers comprise polymerizable groups. A precursor solution comprising nematic monomers and chiral monomers in a solvent is deposited on a substrate, heated to remove the solvent, and then polymerized using UV-VIS-light. The resulting cholesteric liquid crystal polymer (CLCP) reflects light at a wavelength that varies depending on the angle of viewing. The authors disclose that the wavelength of reflected light can be shifted to longer wavelengths if the CLCP layer is deposited on a resin layer comprising polyether moieties.

[0010] To enhance the security of such CLCP features, there is an ongoing need to increase the palette of complexity that is available with CLCP printing, both in design and color.

[0011] SUMMARY OF THE INVENTION

[0012] In a first aspect, the invention provides a method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer B, the method comprising the steps:

[0013] (1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;

[0014] (2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1≥ 5 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B; followed by steps (3), (4), (5) and (6), or alternatively steps (3'), (4'), (5') and (6'): (3) applying the first UV-VIS-curable primer composition A to the substrate, optionally in the form of one or more indicia;

[0015] (4) curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0016] (5) applying the second UV-VIS-curable primer composition B to the substrate and / or to a portion of the primer layer A, optionally in the form of one or more indicia;

[0017] (6) curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0018] OR

[0019] (3') applying the second UV-VIS-curable primer composition B to the substrate, optionally in the form of one or more indicia;

[0020] (4') curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0021] (5') applying the first UV-VIS-curable primer composition A to the substrate and / or to a portion of the primer layer B, optionally in the form of one or more indicia;

[0022] (6') curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A; followed by:

[0023] (7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquid crystal monomer, at least one chiral liquid crystal monomer, at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;

[0024] (8) heating to remove the at least one solvent; and

[0025] (9) polymerizing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

[0026] In a second aspect, the invention provides a security feature comprising:

[0027] (1) the substrate described herein;

[0028] (2) the primer layer described herein on the surface of the substrate, optionally in the form of one or more indicia;

[0029] (3) the layer comprising the cholesteric liquid crystal polymer (“CLCP layer”) described herein on the surface of the primer layers, which CLCP layer may optionally be in the form of one or more indicia; wherein the primer layer comprises a first primer A, which, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ1, a second primer B, which, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ2, wherein Δλr= λ2- λ1≥ 5 nm, and wherein at least a portion of the CLCP layer overlaps at least partially primer A and at least a portion of the CLCP layer overlaps at least partially primer B; wherein the primer A results from curing of the first UV-VIS-curable primer composition A, and the first UV-VIS-curable primer composition A comprises less than at or about 20 wt%, based on the total weight of the primer composition, of aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, and the primer B results from curing of the second UV-VIS-curable primer composition B, and the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3.

[0030] DETAILED DESCRIPTION

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1a shows a cross-section view of a security feature of the invention.

[0033] Figure 1 b shows a cross-section view of a security feature of the invention.

[0034] Figure 1c shows a cross-section view of a security feature of the invention.

[0035] Figure 1d shows a cross-section view of a security feature of the invention.

[0036] Figure 2a depicts a preferred embodiment of a security feature of the invention in cross-section view.

[0037] Figure 2b depicts the security feature of Figure 2a in face-on view.

[0038] Figure 3a depicts a preferred embodiment of a security feature of the invention in cross-section view.

[0039] Figure 3b depicts the security feature of Figure 3a in face-on view.

[0040] Figure 4a depicts a preferred embodiment of a security feature of the invention in cross-section view.

[0041] Figure 4b depicts the security feature of Figure 4a in face-on view.

[0042] Figure 5a depicts a preferred embodiment of a security feature of the invention in cross-section view.

[0043] Figure 5b depicts the security feature of Figure 5a in face-on view.

[0044] Figure 6a depicts an example of a security feature according to the invention.

[0045] Figure 6b depicts an other example of a security feature according to the invention.

[0046] Definitions

[0047] As used herein, the article "a" indicates one as well as more than one and does not necessarily limit its referent noun to the singular.

[0048] As used herein, the term “about” means that the amount or value in question may be the value designated or some other value about the same. The phrases are intended to convey that similar values within a range of ± 5% of the indicated value promote equivalent results or effects according to the invention.

[0049] The term “UV” (ultraviolet) as used herein is intended to mean irradiation having a wavelength component in the UV part of the electromagnetic spectrum; typically from 200 nm to 420 nm.

[0050] As used herein, the term “at least one” is meant to define one or more than one, for example one or two or three.

[0051] As used herein, the term “and / or” means that either all or only one of the elements of said group may be present. For example, “A and / or B” shall mean “only A, or only B, or both A and B”. In the case of “only A”, the term also covers the possibility that B is absent, i.e. “only A, but not B”.

[0052] The term “comprising” as used herein is intended to be non-exclusive and open-ended. Thus, for instance a coating composition comprising a compound A may include other compounds besides A. However, the term “comprising” also covers, as a particular embodiment thereof, the more restrictive meanings of “consisting essentially of' and “consisting of', so that for instance “a fountain solution comprising A, B and optionally C” may also (essentially) consist of A and B, or (essentially) consist of A, B and C.

[0053] The term "security document" refers to a document which is usually protected against counterfeit or fraud by at least one security feature. Examples of security documents include without limitation value documents and value commercial goods.

[0054] The term “security feature” is used to denote an image, pattern or graphic element that can be used for authentication purposes.

[0055] Where the present description refers to “preferred” embodiments / features, combinations of these “preferred” embodiments / features shall also be deemed as disclosed as long as this combination of “preferred” embodiments / features is technically meaningful.

[0056] The term “acrylate” encompasses molecules bearing acrylate and / or (meth)acrylate moieties.

[0057] The term “aliphatic polyurethane” refers to polyurethanes based on compounds in which the isocyanate groups are directly attached to aliphatic carbons.

[0058] The term “aromatic polyurethane” refers to polyurethanes based on compounds in which the isocyanate groups are directly attached to aromatic carbons.

[0059] The term “primer A” means a primer resulting from curing of the first UV-VIS-curable primer composition A.

[0060] The term “primer B” means a primer resulting from curing of the second UV-VIS-curable primer composition B.

[0061] Abbreviations

[0062] PU polyurethane

[0063] CLCP cholesteric liquid crystal polymer

[0064] The inventors have created a novel security feature using cholesteric liquid crystal polymers, as defined by the claims. The various features will be described in more detail.

[0065] Substrate

[0066] The security feature described herein comprises a substrate made of a material selected from the group consisting of transparent materials, light-absorbing materials and combinations thereof.

[0067] Preferred substrates made of one or more transparent materials include without limitation transparent polyolefins such as polyethylene (PE) and polypropylene (PP) including biaxially oriented polypropylene (BOPP), transparent polyamides, transparent polyesters such as poly(ethylene terephthalate) (PET), poly(1 ,4-butylene terephthalate) (PBT), poly(ethylene 2,6-naphthoate) (PEN) and transparent polyvinylchlorides (PVC), more preferably transparent polyesters such as PET.

[0068] “Light absorbing substrates” refers to substrates that absorb at least 50%, preferably at least 60% of the intensity of one or more portions of the visible part of the electromagnetic spectrum (visible spectrum). Said light absorbing substrates may be a continuous layer or may be a discontinuous layer in the form of an indicium or a pattern. Preferably, the light absorbing substrate is a dark substrate, more preferably a black substrate. Should the substrate described herein be a light absorbing substrate, no further additional layer or coating is required to easily observe without any machine or device the color-shifting properties of the overt security feature. Should the substrate not be a light absorbing substrate, an additional light absorbing background, preferably a dark background and more preferably a black background may be present, wherein said dark background may be permanently present or non- permanently present.

[0069] Preferred substrates made of one or more light absorbing materials include without limitation those selected from the group consisting of papers or other fibrous materials (including woven and non-woven fibrous materials), such as cellulose, paper-containing materials, glasses, metals, ceramics, plastics and polymers, metallized plastics or polymers, composite materials and mixtures or combinations of two or more thereof. Typical paper, paper-like or other fibrous materials are made from a variety of fibers including without limitation abaca, cotton, linen, wood pulp, and blends thereof. As is well known to those skilled in the art, cotton and cotton / linen blends are preferred for banknotes, while wood pulp is commonly used in non-banknote security documents.

[0070] Light absorbing substrates may consist of transparent substrates comprising a layer (for example a printed layer) made of one or more light absorbing materials. Should the substrate be made of one or more transparent materials, the overt color-shifting properties of the overt security feature are observed by disposing it on a non-permanent light absorbing background as described herein. The substrate materials mentioned herein are given exclusively for exemplifying purposes, without restricting the scope of the invention. In general, any substrate (which may not necessarily be flat and may be uneven) whose surface is not soluble, or only slightly soluble, in solvent(s) used in the cholesteric liquid crystal polymer precursor composition, or the components of the primer compositions, is a suitable substrate for the purposes of the present invention. As mentioned above, the substrate may advantageously have a dark or black surface or background onto which the primer compositions are applied. Without wishing to be bound by any theory, it is speculated that in the case of a dark or black background the light transmitted by the cholesteric liquid crystal polymer is largely absorbed by the background, whereby any residual backscattering from the background does not disturb the perception of the cholesteric liquid crystal polymer's own reflection with the unaided eye. In contrast, on a substrate with a light or white surface or background the reflection color of the cholesteric liquid crystal polymer is less visible when compared with a black or dark background, due to the strong backscattering from the background. However, even in the case of a light or white background, a cholesteric liquid crystal polymer can be recognized with the help of a circular polarization filter because it selectively reflects only one of the two possible circular polarized light components, in accordance with its chiral helical structure. The background may be in the form of one of more indicia in dark color or black, in which case once the primer layers A and B and the CLCP layer are applied, the one or more indicia will appear as a more intense CLCP reflection and the non-dark or non-black portions will appear as a less intense CLCP reflection.

[0071] The substrate according to the present invention may further comprise additional security elements, such as organic and / or inorganic pigments, dyes, flakes, optically variable elements, magnetic pigments, etc. With the aim of further increasing the security level and the resistance against counterfeiting and illegal reproduction of security documents, the substrate described herein may contain printed, coated, or laser-marked or laser-perforated indicia, watermarks, security threads, fibers, planchettes, luminescent compounds, windows, foils, decals, primers and combinations of two or more thereof, provided that these potential additional features or elements do not negatively interfere with the optical properties of the overt security feature described herein.

[0072] The security feature described herein comprises the primer layer A described herein, the primer layer B and the layer comprising a cholesteric liquid crystal, designated as CLCP layer, described herein, wherein the primer layer A, the primer layer B and the CLCP layer may independently be in the form of one or more indicia and wherein said one or more indicia may the same for the three layers or may be different. As used herein, the term “indicium7“indicia” shall mean continuous and discontinuous layers consisting of distinguishing markings or signs or patterns. Examples of indicia include codes, encoded marks (e.g. encoded alphanumeric data, a one-dimensional barcode, a two-dimensional barcode, a QR- code, datamatrix and IR-reading codes), symbols, alphanumeric symbols, motifs, geometric patterns (e.g. circles, triangles and regular or irregular polygons), letters, words, numbers, logos, drawings, portraits and combinations thereof.

[0073] Primer compositions

[0074] The invention makes use of two (or more) primer compositions:

[0075] 1 . a first UV-VIS-curable primer composition, designated primer composition A, which, when cured and in contact with a CLCP results in a face reflection wavelength of the CLCP of λ1, wherein primer composition A comprises less than at or about 20 wt%, based on the total weight of the primer composition A, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3; and

[0076] 2. a second UV-VIS-curable primer composition, designated primer composition B, which, when cured and in contact with a CLCP results in a face reflection wavelength of the CLCP of λ2, wherein primer composition B comprises greater than or equal to at or about 20 wt%, based on the total weight of the primer composition B, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3; wherein λ1< λ2, and Δλr= λ2- λ15 nm.

[0077] The general requirements for primer composition A and primer composition B are:

[0078] 1. UV-VIS-curable;

[0079] 3. Δλr≥ 5 nm

[0080] In a preferred embodiment, Δλr≥ 10 nm, more preferably Δλr≥ 15 nm, more particularly preferably Δλr≥ 25 nm. The bigger the value of Δλr, generally the more striking the resulting security feature, and the greater the difference in colors reflected from the CLCP layer.

[0081] The primer compositions A and B are UV-VIS-curable, independently including radically-curable components, cationically-curable components, or mixtures of both. Radically-curable components are preferred.

[0082] Preferably the primer compositions A and B independently comprise one or more monomeric UV-VIS- curable components and / or one or more oligomeric UV-VIS-curable components, preferably one or more oligomeric UV-VIS-curable components. Oligomeric, for the purposes of this description, is meant to include molecules having two or more repeating units.

[0083] In a preferred embodiment, the first UV-VIS-curable primer composition A and the second UV-VIS- curable primer composition B are independently acrylate-based, preferably they both independently comprise one or more acrylate oligomers, different from the aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3.

[0084] Preferred radically-curable components for use in the invention are acrylates. For the purposes of this description, the expression acrylates is intended to include (meth)acrylates, and formulae that include one or more acrylate moieties extend to the corresponding formulae in which the one or more acrylate moieties are replaced with one or more (meth)acrylate moieties.

[0085] Acrylates for use in the invention include those having acrylate functionalities of 1 , 2, 3 and greater.

[0086] It is preferred to use one or more oligomeric acrylates, having a functionality of 2, 3 or 4.

[0087] Oligomers for use in the invention include epoxy-based acrylates, such as bisphenol A epoxy resin end- capped with acrylate groups, acrylated oligoamine resins, polyether-based acrylate resins, polyester- based acrylate resins, polyurethane-based acrylate resins different from the aliphatic polyurethane acrylate oligomer having an acrylate functionality of less than 3, and mixtures of these.

[0088] The primer compositions A and B may additionally independently comprise one or more monomeric acrylates having acrylate functionalities of 1 , 2 or greater. Some examples include hexamethylene diacrylate (HDDA), 4-(1-oxo-2-propenyl)-morpholine, pentaerythritol reaction product with acrylic acid, di(trimethylolpropane) tetraacrylate, trimethylolpropane triacrylate, and mixtures of these.

[0089] The primer compositions A and B additionally independently comprise at least one photoinitiator. For radically-curable components, the photoinitiator must be suitable for initiating radical curing. For cationically-curable components (such as epoxy-terminated oligomers and / or monomers). The photoinitiator must be suitable for initiating cationic curing. If a hybrid system is used (radical / cationic), both types of photoinitiator must be used.

[0090] In a preferred embodiment, the primer compositions A and B are based on acrylates and / or (meth)acrylates, and a radical photoinitiator is used. Examples include a-hydroxyketones such as 1- hydroxy-cyclohexyl-phenyl-ketone and a mixture (e.g., about 1 :1) of 1 -hydroxy-cyclohexyl-phenyl- ketone and one or more of benzophenone, 2-hydroxy-2-methyl-1-phenyl-1 -propanone, and 2-hydroxy- 1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1 -propanone; phenylglyoxylates such as methylbenzoylformate and a mixture of oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic 2-[2-hydroxy-ethoxy]-ethyl ester; benzyldimethyl ketals such as alpha, alpha-dimethoxy-alpha-phenylacetophenone; a-aminoketones such as 2-benzyl-2-(dimethylamino)-1- [4-(4-morpholinyl)phenyl]-1 -butanone and 2-methyl-1 -[4-(methylthio)phenyl]-2-(4-morpholinyl)-1 - propanone; phosphine oxide and phosphine oxide derivatives such as diphenyl (2,4,6-trimethylbenzoyl)- phosphine oxide; phenyl bis(2,4,6-trimethylbenzoyl) supplied by GM resins; and also thioxanthone derivatives such as Speedcure ITX (CAS 142770-42-1), Speedcure DETX (CAS 82799-44-8), Speedcure CPTX (CAS 5495-84-1-2 or CAS 83846-86-0) supplied by Lambson. In a preferred embodiment, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methylpropionyl)phenoxy]phenyl]-2-methylpropanone is used as photoinitiator.

[0091] The primer compositions A and B may additionally independently comprise fillers, such as, for example, talcs, micas (e.g. muscovites), montmorillonites, bentonites, wollastonites, halloysites, calcined clays, china clays, carbonates (e.g. calcium carbonate, magnesium carbonate), silicates (e.g. magnesium silicate, aluminium silicate), vermiculites, amorphous silica (e.g. fumed silica, precipitated silica, silica flour), wood flours (sawdust), natural fibers, synthetic fibers (such as carbon fibers or carbon nanotubes) and mixtures thereof; preferably selected from the group consisting of talcs, micas, wollastonites, calcined clays, carbonates, amorphous silica and mixtures thereof.

[0092] The primer compositions A and B may additionally independently comprise other additives, such as, but not limited to, UV stabilizers.

[0093] In a preferred embodiment, the primer compositions A and B independently comprise at least one polyether acrylate oligomer.

[0094] In a preferred embodiment, the primer compositions A and B independently comprise an oligomer that is an amine-modified acrylate, more preferably an amine-modified acrylate together with glycerol propoxylate triacrylate and trimethylolpropane triacrylate.

[0095] In a particularly preferred embodiment, the primer compositions A and B independently comprise an oligomer mixture that is at or about 77 wt% amine-modified acrylate in admixture with at or about 15 wt% glycerol propoxylate triacrylate, and at or about 8 wt% trimethylolpropane triacrylate, based on the total weight of the oligomer mixture.

[0096] In another particularly preferred embodiment, the primer compositions A and B independently comprise at or about 25-80 wt%, preferably at or about 30-75 wt% of an oligomer that is an amine-modified acrylate, based on the total weight of the primer composition, more preferably an amine-modified acrylate together with glycerol propoxylate triacrylate and trimethylolpropane triacrylate.

[0097] In a preferred embodiment, the primer compositions A and B independently comprise a polyurethane acrylate oligomer, preferably at at or about 10-60 wt%, more preferably at at or about 15-55 wt%, based on the total weight of primer composition A and B, respectively.

[0098] The first UV-VIS-curable primer composition A comprises less than at or about 20 wt%, based on the total weight of the first UV-VIS-curable primer composition A, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3.

[0099] The second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt%, based on the total weight of the second UV-VIS-curable primer composition B, of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of less than 3. In a preferred embodiment, the aliphatic polyurethane acrylate oligomer has an acrylate functionality of less than 2.5, more preferably 2 or less, based on the total weight of the second UV-VIS-curable primer composition B.

[0100] In a preferred embodiment, the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of less than 3, up to 85 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of less than 3, based on the total weight of the primer composition B.

[0101] In another preferred embodiment, the second UV-VIS-curable primer composition B comprises greater than at or about 25 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of less than 3, based on the total weight of the primer composition B. In another preferred embodiment, the second UV-VIS-curable primer composition B comprises greater than at or about 35 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of less than 3, based on the total weight of the primer composition B.

[0102] In another preferred embodiment, the second UV-VIS-curable primer composition B comprises greater than at or about 45 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of less than 3, the weight percent being based on the total weight of the primer composition B.

[0103] In another preferred embodiment, the second UV-VIS-curable primer composition B comprises greater than at or about 25 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of 2 or less, based on the total weight of the primer composition B.

[0104] In another preferred embodiment, the second UV-VIS-curable primer composition B comprises greater than at or about 35 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of 2 or less, based on the total weight of the primer composition B.

[0105] In another preferred embodiment, the second UV-VIS-curable primer composition B comprises greater than at or about 45 wt% of an aliphatic polyurethane acrylate oligomer, having an acrylate functionality of 2 or less, based on the total weight of the primer composition B.

[0106] Cholesteric liquid crystal polymer (CLCP)

[0107] The cholesteric liquid crystal precursor composition comprises (I) one or more nematic compounds and (II) one or more chiral liquid crystal monomers which are capable of giving rise to a cholesteric liquid crystal state of the cholesteric liquid crystal precursor composition upon heating. The pitch of the obtainable cholesteric state depends on the relative ratio of the nematic and the chiral liquid crystal monomers. The (total) concentration of the one or more nematic compounds in the cholesteric liquid crystal precursor composition for use in the present invention is at or about 4 to at or about 30, preferably at or about 4 to at or about 25, times the (total) concentration of the one or more chiral liquid crystal monomers. The one or more chiral liquid crystal monomers are preferably present in an amount from at or about 0.1 wt% to at or about 30 wt%, more preferably from at or about 0.1 wt% to at or about 20 wt%, and still more preferably from at or about 3 wt% to at or about 10 wt%, based on the total weight of the cholesteric liquid crystal precursor composition. The one or more nematic compounds are preferably present in an amount from at or about 20 wt% to at or about 50 wt%, more preferably in an amount from at or about 30 wt% to at or about 45 wt%, based on the total weight of the cholesteric liquid crystal precursor composition.

[0108] Both the one or more nematic compounds and the one or more chiral liquid crystal monomers comprise at least one polymerizable group. For example, all of the one or more nematic compounds and all of the one or more chiral liquid crystal monomers may comprise at least one polymerizable group. The at least one polymerizable group may, for example, comprise a group which is able to take part in a free radical polymerization and in particular, an unsaturated carbon-carbon bond such as for example an acrylate group with formula H2C=CH-C(O)-O or H2C=C(CH3)-C(O)-O.

[0109] Nematic (precursor) compounds which are suitable for use in the cholesteric liquid crystal precursor composition are known in the art; when used alone (i.e., without chiral liquid crystal monomers) they arrange themselves in a state characterized by its birefringence. Non-limiting examples of nematic compounds that are suitable for use in the present invention are described in, e.g., WO 93 / 22397 A1, WO 95 / 22586 A1 , EP 0 847 432 B1, US 6,589,445, US 2007 / 0224341. The entire disclosures of these documents are incorporated herein by reference.

[0110] A preferred class of nematic compounds for use in the present invention comprises one or more polymerizable groups, identical or different from each other, per molecule. Examples of polymerizable groups include groups that are capable of taking part in a free radical polymerization, and in particular, groups comprising a carbon-carbon double or triple bond such as for example an acrylate moiety, a vinyl moiety or an acetylenic moiety. Particularly preferred as polymerizable groups are acrylate moieties. The nematic compounds for use in the present invention further may comprise one or more optionally substituted aromatic groups, preferably phenyl groups. Examples of the optional substituents of the aromatic groups include those which are set forth herein as examples of substituent groups on the phenyl rings of the chiral liquid crystal monomers of formula (I) such as for example alkyl and alkoxy groups.

[0111] Examples of groups which may optionally be present to link the polymerizable groups and the aryl (e.g., phenyl) groups in the nematic compounds include those which are exemplified herein for the chiral liquid crystal monomers of formula (I) (including those of formula (IA) and formula (IB) set forth below). For example, the nematic compounds may comprise one or more groups of formulae (i) to (vi) which are indicated below as examples for A1and A2in formula (I) (and formulae (IA) and (IB)), typically bonded to optionally substituted phenyl groups.

[0112] Non-limiting specific examples of nematic compounds which are suitable for use in the present invention include without limitation the following compounds: 2-methoxybenzene-1 ,4-diyl bis[4-({[4- (acryloyloxy)butoxy]carbonyl)oxy)benzoate]; 4-{[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)benzoyl]oxy}- 2-methoxyphenyl 4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)-2-methylbenzoate; 2-methoxybenzene-1 ,4- diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)-2-methyl-benzoate]; 2-methylbenzene-1 ,4-diyl bis[4- ({[4-(acryloyloxy)butoxy]carbonyl}oxy)-2-methyl-benzoate];4-{[4-({[4- (acryloyloxy)butoxy]carbonyl}oxy)benzoyl]oxy}-2-methylphenyl-4-({[4-(acryloyloxy)butoxy]carbonyl}- oxy)-3-methoxybenzoate;2-methylbenzene-1 ,4-diylbis[4-({[4-(acryloyloxy)butoxy]- carbonyl}oxy)benzoate]; 2-methylbenzene-1 ,4-diyl-bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)-3- methoxy-benzoate];4-{[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)-3-methoxybenzoyl]oxy}-2-methyl- phenyl 4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)-3,5-dimethoxybenzoate; 2-methylbenzene-1 ,4-diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)-3,5-dimethoxy-benzoate]; 2-methoxybenzene-1,4-diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)-3,5-di-methoxybenzoate];4-{[4-({[4- (acryloyloxy)butoxy]carbonyl}oxy)-3-methoxybenzoyl]oxy}-2-methoxyphenyl-4-({[4-(acryloyloxy)- butoxy]carbonyl)oxy)-3,5-dimethoxybenzoate; 4-({4-[4-(acryloyloxy)butoxy]benzoyl}oxy)-3- methylphenyl 4-[4-(acryloyloxy)butoxy]-2-methylbenzoate; 4-({4-[4-(acryloyloxy)butoxy]benzoyl)oxy)-3- methylphenyl 4-[4-(acryloyloxy)butoxy]-3-methylbenzoate; 2-methylbenzene-1 ,4-diyl bis{4-[4- (acryloyloxy)butoxy]-2-methylbenzoate}; 4-({4-[4-(acryloyloxy)butoxy]-2-methylbenzoyl}oxy)-3- methylphenyl 4-[4-(acryloyl-oxy)butoxy]-2,5-dimethylbenzoate; 2-methylbenzene-1 ,4-diyl bis{4-[4- (acryloyloxy)butoxy]-2,5-dimethylbenzoate}-2-methylbenzene-1 ,4-diyl-bis{4-[4-(acryloyl- oxy)butoxy]benzoate); 4-({4-[4-(acryloyloxy)butoxy]-3,5-dimethylbenzoyl}oxy)-3-methylphenyl 4-[4- (acryloyloxy)butoxy]-2,5-dimethylbenzoate; 2-methylbenzene-1,4-diyl bis{4-[4-(acryloyloxy)butoxy]-3,5- dimethylbenzoate}; 2-methoxybenzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-3,5-dimethylbenzoate}; 4- ({4-[4-(acryloyloxy)butoxy]-3-methylbenzoyl}oxy)-2-methoxyphenyl-4-[4-(acryloyl-oxy)butoxy]-3,5- dimethylbenzoate; 2-methoxybenzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-3-methylbenzoate}; 4-({4- [4-(acryloyloxy)butoxy]benzoyl}oxy)-3-methoxyphenyl 4-[4-(acryloyloxy)-butoxy]-3-methylbenzoate; 4- ({4-[4-(acryloyloxy)butoxy]benzoyl}oxy)-3-methoxyphenyl-4-[4-(acryloyloxy)-butoxy]-2,5- dimethylbenzoate; 2-methoxybenzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-2-methoxybenzoate}; 2- methoxybenzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-3,5-dimethoxybenzoate}; 2-methoxybenzene- 1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-3-methoxybenzoate}; 2-ethoxybenzene-1 ,4-diyl bis{4-[4- (acryloyloxy)butoxy]benzoate}; 2-ethoxybenzene-1 ,4-diyl-bis{4-[4-(acryloyloxy)butoxy]-2- methylbenzoate}; 2-(propan-2-yloxy)benzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]benzoate}; 4-({4-[4- (acryloyloxy)butoxy]benzoyl}oxy)-2-(propan-2-yloxy)phenyl-4-[4-(acryloyl-oxy)butoxy]-2- methylbenzoate; 2-(propan-2-yloxy)benzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-2-methylbenzoate}; 2-(propan-2-yloxy)benzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-2,5-dimethyl-benzoate}; 2-(propan-2- yloxy)benzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-3,5-dimethyl-benzoate}; and 2-(propan-2- yloxy)benzene-1 ,4-diyl bis{4-[4-(acryloyloxy)butoxy]-3,5-dimethoxy-benzoate}.

[0113] In a preferred embodiment, the nematic monomer is 2-methylbenzene-1 ,4-diyl bis[4-({[4- (acryloyloxy)butoxy]carbonyl}oxy)benzoate].

[0114] The one or more chiral liquid crystal monomers for use in the present invention preferably comprise at least one polymerizable group. Suitable examples of the one or more chiral liquid crystal monomers include those of formula (I): wherein:

[0115] R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl and C1-C6alkoxy;

[0116] A1and A2each independently denote a group of formula (i) to (vi):

[0117] (i) -[(CH2)y-O]z-C(O)-CH=CH2;

[0118] (ii) -C(O)-D1-O-[(CH2)y-O]z-C(O)-CH=CH2;

[0119] (iii) -C(O)-D2-O-[(CH2)y-O]z-C(O)-CH=CH2;

[0120] (iv) -[COO-(CH2)y-O]z-C(O)-CH=CH2;

[0121] (v) -C(O)- D1-O-[COO-(CH2)y-O]z-C(O)-CH=CH2;

[0122] (vi) -C(O)-D2-O-[ COO- (CH2)y-O]z-C(O)-CH=CH2;

[0123] D1denotes a group of formula

[0124] D2denotes a group of formula m, n, o, p, q, r, s, and t each independently denote 0, 1 , or 2; y denotes 0, 1 , 2, 3, 4, 5, or 6; z equals 0 if y equals 0 and z equals 1 if y equals 1 to 6.

[0125] In one embodiment, the one or more chiral liquid crystal monomers may comprise one or more isomannide derivatives of formula (IA): wherein:

[0126] R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl and C1-C6alkoxy;

[0127] A1and A2each independently denote a group of formula (i) to (vi):

[0128] (i) -[(CH2)y-O]z-C(O)-CH=CH2;

[0129] (ii) -C(O)-D1-O-[(CH2)y-O]z-C(O)-CH=CH2;

[0130] (iii) -C(O)- D2-O-[(CH2)y-O]z-C(O)-CH=CH2;

[0131] (iv) -[COO-(CH2)y-O]z-C(O)-CH=CH2;

[0132] (v) -C(O)-D1-O-[COO-(CH2)y-O]z-C(O)-CH=CH2;

[0133] (vi) -C(O)-D2-O-[ COO- (CH2)y-O]z-C(O)-CH=CH2;

[0134] D1denotes a group of formula: D2denotes a group of formula m, n, o, p, q, r, s, and t each independently denote 0, 1 , or 2; y denotes 0, 1 , 2, 3, 4, 5, or 6; z equals 0 if y equals 0 and z equals 1 if y equals 1 to 6.

[0135] In one exemplary embodiment of the compounds of formula (IA) (and of compounds of formula (I)), R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl. In an alternative embodiment, R1, R2, R3, R4, R5, R6, R7and R8in formula (IA) (and in formula (I)) each independently denote C1-C6alkoxy. In another exemplary embodiment of the compounds of formula (I) and of formula (IA), A1and A2each independently denote a group of formula -[(CH2)y-O]z-C(O)-CH=CH2; R1, R2, Rs and R4each independently denote C1-C6alkyl; and m, n, 0, and p each independently denote 0, 1 , or 2. In yet another embodiment, A1and A2in formula (I) and formula (IA) each independently denote a group of formula - [(CH2)y-O]z-C(O)-CH=CH2; R1, R2, R3and R4each independently denote C1-C6alkoxy; and m, n, o, and p each independently denote 0, 1 , or 2.

[0136] In another embodiment of the compounds of formula (IA) (and of formula (I)), A1and A2each independently denote a group of formula -C(O)-D1-O-[(CH2)y-O]z-C(O)-CH=CH2and / or of formula - C(O)-D2-O-[(CH2)y-O]z-C(O)-CH=CH2; and R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl. In an alternative embodiment, A1and A2in formula (IA) (and in formula (I)) each independently denote a group of formula -C(O)-D1-O-[(CH2)y-O]z-C(O)-CH=CH2and / or a group of formula -C(O)-D2-O-[(CH2)y-O]z-C(O)-CH=CH2; and R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkoxy.

[0137] In another embodiment of the compounds of formula (IA) (and of formula (I)), A1and A2each independently denote a group of formula -C(O)-D1-O-[COO-(CH2)y-O]z-C(O)-CH=CH2and / or of formula -C(O)-D2-O-[COO- (CH2)y-O]z-C(O)-CH=CH2; and R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl. In an alternative embodiment, A1and A2in formula (IA) (and in formula (I)) each independently denote a group of formula -C(O)-D1-O-[COO-(CH2)y-O]z-C(O)-CH=CH2and / or of formula -C(O)-D2-O-[COO- (CH2)y-O]z-C(O)-CH=CH2; and R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkoxy.

[0138] In another embodiment, the one or more chiral liquid crystal monomers may comprise one or more isosorbide derivatives represented by formula (IB):

[0139] (IB) wherein:

[0140] R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl and C1-C6alkoxy;

[0141] 5 A1and A2each independently denote a group of formula (i) to (vi):

[0142] (i) -[(CH2)y-O]z-C(O)-CH=CH2;

[0143] (ii) -C(O)-D1-O-[(CH2)y-O]z-C(O)-CH=CH2;

[0144] (iii) -C(O)-D2-O-[(CH2)y-O]z-C(O)-CH=CH2;

[0145] (iv) -[COO-(CH2)y-O]z-C(O)-CH=CH2;

[0146] 10 (v) -C(O)-D1-O-[COO-(CH2)y-O]z-C(O)-CH=CH2;

[0147] (vi) -C(O)-D2-O-[ COO- (CH2)y-O]z-C(O)-CH=CH2;

[0148] D1denotes a group of formula:

[0149] 15 D2denotes a group of formula: m, n, o, p, q, r, s, and t each independently denote 0, 1 , or 2; y denotes 0, 1 , 2, 3, 4, 5, or 6;

[0150] 20 z equals 0 if y equals 0 and z equals 1 if y equals 1 to 6.

[0151] In one embodiment of the compounds of formula (IB), R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl; and m, n, 0, and p each independently denote 0, 1 , or 2. In an alternative embodiment, R1, R2, R3, R4, R5, R6, R7and R8in formula (IB) each independently denote C1-

[0152] 15 C6alkoxy; and m, n, o, and p each independently denote 0, 1, or 2. In another embodiment of the compounds of formula (IB), A1and A2each independently denote a group of formula -[(CH2)y-O]z-C(O)-CH=CH2; R1, R2, R3and R4each independently denote C1-C6alkyl; and m, n, 0, and p each independently denote 0, 1 , or 2. In yet another embodiment, A1 and A2 in formula (IB) each independently denote a group of formula -[(CH2)y-O]z-C(O)-CH=CH2; R1, R2, R3and R4each independently denote C1-C6alkoxy; and m, n, o, and p each independently denote 0, 1 , or 2.

[0153] In another embodiment of the compounds of formula (IB), A1and A2each independently denote a group of formula -C(O)-D1-O-[(CH2)y-O]z-C(O)-CH=CH2and / or of formula -C(O)-D2-O-[(CH2)y-O]z-C(O)- CH=CH2; R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl; and m, n, 0, and p each independently denote 0, 1 , or 2. In an alternative embodiment, A1and A2in formula (IB) each independently denote a group of formula -C(O)-D1-O-[(CH2)y-O]z-C(O)-CH=CH2and / or a group of formula -C(O)-D2-O-[(CH2)y-O]z-C(O)-CH=CH2; R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkoxy ; and m, n, 0, and p each independently denote 0, 1, or 2.

[0154] In another embodiment of the compounds of formula (IB), A1and A2each independently denote a group of formula -C(O)-D1-O-[COO-(CH2)y-O]z-C(O)-CH=CH2and / or of formula — C(O)-D2-O-[COO- (CH2)y- O]Z-C(O)-CH=CH2; R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkyl; and m, n, o, and p each independently denote 0, 1 , or 2.

[0155] In an alternative embodiment, A1and A2in formula (IB) each independently denote a group of formula -C(O)-D1-O-[COO-(CH2)y-O]z-C(O)-CH=CH2and / or a group of formula -C(O)-D2-O-[COO- (CH2)y-O]z- C(O)-CH=CH2; R1, R2, R3, R4, R5, R6, R7and R8each independently denote C1-C6alkoxy ; and m, n, 0, and p each independently denote 0, 1 , or 2.

[0156] Non-limiting examples of chiral liquid crystal monomers of formula (I) for use in the present invention include without limitation the following compounds: 2,5-bis-O-(4-{[4-(acryloyloxy)-3- methoxybenzoyl]oxy}-3-methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy) -3- methoxybenzoyl]oxy}-3-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methoxybenzoyl]oxy}-benzoyl)- 1,4:3,6-dianhydro-D-mannitol; 2,5-bis-O-(4-{[4-(acryloyloxy)-benzoyl]oxy}-benzoyl)-1 ,4:3,6-dianhydro- D-mannitol; 2,5-bis-O-(4-{[4-(acryloyloxy)-butoxy]-benzoyl})-1,4:3,6-dianhydro-D-mannitol; 2,5-bis-O- [4-(acryloyloxy)-2-methylbenzoyl]-1 ,4:3,6-dianhydro-D-mannitol; 2,5-bis-O-(4-{[4-(acryloyloxy)-3- methoxybenzoyl]oxy}-benzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2,5-bis-O-(4-{[4-(acryloyloxy)- benzoyl]oxy}-3-methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2- methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-benzoyl]oxy}-3-methoxybenzoyl)-1 ,4:3,6-dianhydro-D- mannitol; 2,5-bis-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-2- methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-

[0157] (acryloyloxy)benzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methylbenzoyl]oxy}-2- methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2- methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro- D-mannitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-2,5- dimethylbenzoyl]oxy}-2-methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2,5- dimethylbenzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methylbenzoyl]oxy}-2- methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxy-5- methylbenzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methylbenzoyl]oxy}-2- methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxybenzoyl]oxy}-2- methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro- D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxybenzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-

[0158] (acryloyloxy)-3-methoxybenzoyl]oxy}-2-methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4- (acryloyloxy)-2-methoxybenzoyl]oxy}benzoyl)-5-O-(4-{[4-(acryloyloxy)-3- methoxybenzoyl]oxy}benzoyl)-1,4:3,6-dianhydro-D-mannitol; 2,5-bis-O-(4-{[4-

[0159] (acryloyloxy)benzoyl]oxy}-3-methoxybenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2- methoxybenzoyl]oxy}-2,5-dimethylbenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methoxybenzoyl]oxy}-3- methylbenzoyl)-1 ,4:3,6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxybenzoyl]oxy}-2- methylbenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methoxybenzoyl]oxy}-3-methylbenzoyl)-1 , 4:3, 6-dian hydro- D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxy-5-methylbenzoyl]oxy}-2-methylbenzoyl)-5-O-(4-{[4- (acryloyloxy )-5-methoxy-2-methylbenzoyl]oxy}-3-methylbenzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2-O-(4- {[4-(acryloyloxy)benzoyl]oxy}-2-ethoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-ethoxybenzoyl]oxy}benzoyl)- 1,4:3, 6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2-ethoxy-5-methylbenzoyl)-5-O-(4- {[4-(acryloyloxy)-3-ethoxybenzoyl]oxy}benzoyl)-1, 4:3, 6-dianhydro-D-mannitol; 2-O-(4-{[4-

[0160] (acryloyloxy)benzoyl]oxy}-2-ethoxy-5-methylbenzoyl)-5-O-(4-{[4-(acryloyloxy)-5-ethoxy-2- methylbenzoyl]oxy}benzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)-3- ethoxybenzoyl]oxy}benzoyl)-5-O-(4-{[4-(acryloyloxy)-2-methylbenzoyl]oxy}-2-ethoxybenzoyl)-1 ,4:3,6- dianhydro-D-mannitol; 2-O-(4-{[4-(acryloyloxy)-2,5-dimethylbenzoyl]oxy}-2-ethoxybenzoyl)-5-O-(4-{[4- (acryloyloxy)-2-methylbenzoyl]oxy}-2-ethoxybenzoyl)-1, 4:3, 6-dianhydro-D-mannitol; 2,5-bis-O-(4-{[4-

[0161] (acryloyloxy)-2,5-dimethylbenzoyl]oxy}-2-ethoxybenzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2,5-bis-O-(4- {[4-(acryloyloxy)-2-ethoxybenzoyl]oxy}-2-ethoxybenzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2,5-bis-O-(4- {[4-(acryloyloxy)-2-methoxybenzoyl]oxy}-2-ethoxybenzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2,5-bis-O-(4- {[4-(acryloyloxy)-2-ethoxybenzoyl]oxy}-2-methoxybenzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2,5-bis-O-(4- {[4-(acryloyloxy)-2-ethoxybenzoyl]oxy}-3-methylbenzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2,5-bis-O-(4- {[4-(acryloyloxy)-2-ethoxybenzoyl]oxy}-3-methoxybenzoyl)-1 , 4:3, 6-dianhydro-D-mannitol; 2,5-bis-O-(4- {[4-(acryloyloxy)-3-methoxybenzoyl]oxy}-3-methoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; D-glucitol 1,4:3,6-dianhydro-bis[4-[[4-[[[4-[(1-oxo-2-propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate]; 2,5- bis-O-(4-{[4-(acryloyloxy)-benzoyl]oxy}-3-methoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4- (acryloyloxy)benzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-benzoyl]oxy}-3- methoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2- methoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2- methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-2-methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro- D-glucitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3- methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2-0-(4-{[4-(acryl- oyloxy)benzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-2,5-dimethylbenzoyl]oxy}-2- methoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)-2,5-dimethylbenzoyl]oxy}-2- methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro- D-glucitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxy-5-methylbenzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4- (acryloyloxy)-3-methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4- (acryloyloxy)-2-methoxybenzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3- methylbenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4-

[0162] (acryloyloxy)benzoyl]oxy}-3-methoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)-2- methoxybenzoyl]oxy}-2-methoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methoxybenzoyl]oxy}-2- methoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxy- benzoyl]oxy}benzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methoxybenzoyl]oxy}benzoyl)-1 ,4:3,6-dianhydro-D- glucitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxybenzoyl]oxy}-2,5-dimethylbenzoyl)-5-O-(4-{[4-(acryloyloxy)- 3-methoxybenzoyl]oxy}-3-methylbenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)-2- methoxybenzoyl]oxy}-2-methylbenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-methoxybenzoyl]oxy}-3- methylbenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)-2-methoxy-5-methylbenzoyl]oxy}- 2-methylbenzoyl)-5-O-(4-{[4-(acryloyloxy)-5-methoxy-2-methylbenzoyl] oxy}-3-methylbenzoyl)-1, 4:3,6- dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2-ethoxybenzoyl)-5-O-(4-{[4-(acryloyloxy)-3- ethoxybenzoyl]oxy}benzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2- ethoxy-5-methylbenzoyl)-5-O-(4-{[4-(acryloyloxy)-3-ethoxybenzoyl]oxy}benzoyl)-1 ,4:3,6-dianhydro-D- glucitol; 2-O-(4-{[4-(acryloyloxy)benzoyl]oxy}-2-ethoxy-5-methylbenzoyl)-5-O-(4-{[4-(acryloyloxy)-5- ethoxy-2-methylbenzoyl]oxy}benzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)-3- ethoxybenzoyl]oxy}benzoyl)-5-O-(4-{[4-(acryloyloxy)-2-methylbenzoyl]oxy}-2-ethoxybenzoyl)-1 ,4:3,6- dianhydro-D-glucitol; 2-O-(4-{[4-(acryloyloxy)-2,5-dimethylbenzoyl]oxy}-2-ethoxybenzoyl)-5-O-(4-{[4- (acryloyloxy)-2-methylbenzoyl]oxy}-2-ethoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4- (acryloyloxy)-2,5-dimethylbenzoyl]oxy}-2-ethoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4- (acryloyloxy)-2-ethoxybenzoyl]oxy}-2-ethoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4-(ac- ryloyloxy)-2-methoxybenzoyl]oxy}-2-ethoxybenzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4- (acryloyloxy)-2-ethoxybenzoyl]oxy}-2-methoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4- (acryloyloxy)-2-ethoxybenzoyl]oxy}-3-methylbenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4- (acryloyloxy)-2-ethoxybenzoyl]oxy}-3-methoxybenzoyl)-1,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-[4- (acryloyloxy)benzoyl]-1 ,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-[4-(acryloyloxy)benzoyl]-1 ,4:3,6- dianhydro-D-mannitol; 2,5-bis-O-(4-{[4-({[4-(acryloyloxy)-butoxy]carbonyl}oxy)benzoyl]oxy}-benzoyl)- 1,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4-({[4-(acryloyloxy)-butoxy]carbonyl}oxy)-3- methoxybenzoyl]oxy}-benzoyl)-1 ,4:3,6-dianhydro-D-glucitol; 2,5-bis-O-(4-{[4-({[6-(acryloyloxy)- hexyloxy]carbonyl}-oxy)benzoyl]oxy}-benzoyl)-1,4:3,6-dianhydro-D-glucitol; and 2,5-bis-O-[4-({[4- (acryloyloxy)-butoxy]carbonyl}oxy)benzoyl]-1 ,4:3,6-dianhydro-D-glucitol.

[0163] In a preferred embodiment, the chiral liquid crystal monomer is D-Glucitol 1 ,4:3,6-dianhydro-bis[4-[[4- [[[4-[(1-oxo-2-propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate],

[0164] The cholesteric liquid crystal precursor composition comprises one or more solvents. Suitable solvents are known to those skilled in the art and include without limitation low-viscosity, slightly polar and aprotic organic solvents, such as for example methyl ethyl ketone (MEK), acetone, cyclopentanone, cyclohexanone, ethyl acetate, ethyl 3-ethoxypropionate, and mixtures of two or more thereof. Cyclohexanone is particularly preferred. The one or more solvents are preferably present in an amount from at or about 30 wt% to at or about 70 wt%, more preferably from at or about 40 to at or about 60 wt%, based on the total weight of the cholesteric liquid crystal precursor composition.

[0165] The CLCP precursor composition described herein further comprises one or more photoinitiators. Non- limiting examples of the many suitable photoinitiators for the cholesteric liquid crystal precursor composition described herein include a-hydroxyketones such as 1-hydroxy-cyclohexyl-phenyl-ketone and a mixture (e.g., at or about 1 :1) of 1-hydroxy-cyclohexyl-phenyl-ketone and one or more of benzophenones, 2-hydroxy-2-methyl-1-phenyl-1 -propanone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]- 2-methyl-1 -propanone and 2-hydroxy-1-[4-[4-(1-hydroxy-2-methylpropanoyl)phenoxy]phenyl]-2- methylpropan-1-one (sold for example by IGM Resins under the name ESACURE® KIP 160); phenylglyoxylates such as methylbenzoylformate and a mixture of oxy-phenyl-acetic acid 2-[2-oxo-2- phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic 2-[2-hydroxy-ethoxy]-ethyl ester; benzyldimethyl ketals such as alpha, alpha-dimethoxy-alpha-phenylacetophenone; a-aminoketones such as 2-benzyl-2-(dimethylamino)-1 -[4-(4-morpholinyl)phenyl]-butan-1 -one, 2-dimethylamino-2-(4- methyl-benzyl)-1 -(4-morpholin-4-yl-phenyl)-butan-1 -one and 2-methyl-1 -[4-(methylthio)phenyl]-2-(4- morpholinyl)-1 -propanone; phosphine oxide and phosphine oxide derivatives such as diphenyl (2,4,6- trimethylbenzoyl)-phosphine oxide; phenyl-bis(2,4,6-trimethylbenzoyl)-phosphine oxide and also thioxanthone derivatives such as those described herein.

[0166] The one or more photoinitiators are preferably present in an amount from at or about 0.01 wt% to at or about 10 wt%, more preferably from at or about 0.05 wt% to at or about 7 wt%, based on the total weight of the cholesteric liquid crystal precursor composition.

[0167] In a preferred embodiment, the CLCP precursor composition comprises 2-hydroxy-1-[4-[4-(1-hydroxy- 2-methylpropanoyl)phenoxy]phenyl]-2-methylpropan-1-one as photoinitiator, preferably at 0.7-2.5 wt%, more preferably at 0.8-1 .5 wt%, the weight percentages being based on the total weight of the CLCP precursor composition.

[0168] The cholesteric liquid crystal precursor composition described herein may further comprise one or more optional additives, provided that said one or more additives do not negatively disturb or interfere with the formation of the helix and / or the formation of the polymer, said one or more additives including without limitation compounds and materials which are used for adjusting physical, rheological and chemical parameters of the composition such as the consistency (e.g. anti-settling agents and plasticizers), foaming properties (e.g. antifoaming agents and deaerators), lubricating properties (waxes), radiation sensitizers, UV stability (photostabilizers), adhesion properties, surface properties (wetting agents, hydrophilisizing and hydrophobisizing agents), etc. When present, the one or more additives comprised in the cholesteric liquid crystal precursor composition are preferably present in an amount from at or about 0.01 wt% to at or about 5 wt%, based on the total weight of the cholesteric liquid crystal precursor composition.

[0169] In a preferred embodiment, the cholesteric liquid crystal precursor composition comprises 2- methylbenzene-1,4-diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl)oxy)benzoate] as nematic monomer and D-glucitol 1 ,4:3,6-dianhydro-bis[4-[[4-[[[4-[(1 -oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate] as chiral monomer, preferably 30-45 wt% 2- methylbenzene-1,4-diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)benzoate] as nematic monomer, and 0.7-2.5 wt% D-Glucitol 1 ,4:3,6-dianhydro-bis[4-[[4-[[[4-[(1 -oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate] as chiral monomer, the weight percentages being based on the total weight of the cholesteric liquid crystal precursor composition.

[0170] In another preferred embodiment, the cholesteric liquid crystal precursor composition comprises 2- methylbenzene-1,4-diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)benzoate] as nematic monomer and D-glucitol 1 ,4:3,6-dianhydro-bis[4-[[4-[[[4-[(1 -oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate] as chiral monomer, and 2-hydroxy-1-[4-[4-(1- hydroxy-2-methylpropanoyl)phenoxy]phenyl]-2-methylpropan-1 -one as photoinitiator.

[0171] In another preferred embodiment, the cholesteric liquid crystal precursor composition comprises 30-45 wt% 2-methylbenzene-1,4-diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)benzoate] as nematic monomer, and 0.7-2.5 wt% D-Glucitol 1 ,4:3,6-dianhydro-bis[4-[[4-[[[4-[(1-oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate] as chiral monomer, and 2-hydroxy-1-[4-[4-(1- hydroxy-2-methylpropanoyl)phenoxy]phenyl]-2-methylpropan-1-one as photoinitiator at 0.7-2.5 wt%, more preferably at 0.8-1 .5 wt%, wherein the weight percentages are based on the total weight of the cholesteric liquid crystal precursor composition.

[0172] Examples of embodiments of the method of the invention

[0173] The method of the invention comprises a step of applying the first UV-VIS-curable primer composition A to the substrate and applying the second UV-VIS-curable primer composition B to the substrate and / or to the cured first UV-VIS-curable primer composition A.

[0174] In a preferred embodiment, steps (3) and (5) are independently carried out using a printing method, preferably selected from flexography printing processes, gravure printing processes, ink-jet printing processes, screen printing processes and offset printing processes.

[0175] In a preferred embodiment, step (7) is carried out by a printing method, preferably selected from flexography printing processes, gravure printing processes, ink-jet printing processes and screen- printing processes.

[0176] Steps (4), (6) and (9) are preferably carried out with the one or more light sources so as to cure the primer compositions A and B and polymerize the cholesteric liquid crystal precursor composition, wherein said one or more light sources are preferably selected from the group consisting of arc discharge lamp such as mercury lamps (preferably medium-pressure mercury lamps), UV-VIS-LED lamps and sequences thereof described herein.

[0177] Examples of embodiments of this process are described in more detail referring to Figures 1 to 5.

[0178] Figure 1a shows a cross-section view of a security feature of the invention. The substrate (1) is dark or black on its surface. Primer composition A (2a) is applied to the surface of the substrate, in this case it covers the entire surface of the substrate. It is then cured. Primer composition B (2b) is applied to the surface of primer A (2a) in the form of an indicium, and subjected to curing. The cholesteric liquid crystal precursor composition (3) is applied overtop of primer layers A (2a) and B (2b), and subjected to polymerization.

[0179] Figure 1 b shows a cross-section view of a security feature of the invention. The substrate (1 ) is dark or black on its surface. Primer composition B (2b) is applied to the surface of the substrate, in this case it covers the entire surface of the substrate. It is then cured. Primer composition A (2a) is applied to the surface of primer B (2b), and subjected to curing. The cholesteric liquid crystal precursor composition (3) is applied overtop of primer layers A (2a) and B (2b), and subjected to polymerization.

[0180] Figure 1c shows a cross-section view of a security feature of the invention. Primer composition A (2a) is applied to the surface of the substrate (1), and subjected to curing. Primer composition B (2b) is applied to the surface of the substrate (1), and subjected to curing. These steps may be carried out in the opposite order, i.e. primer composition B may be applied before primer composition A, or they may be carried out simultaneously with simultaneous curing. The cholesteric liquid crystal precursor composition (3) is applied overtop of primer layers A (2a) and B (2b), and subjected to polymerization.

[0181] Figure 1d shows a cross-section view of a security feature of the invention. Primer composition A (2a) is applied to the surface of the substrate (1), and subjected to curing. Primer composition B (2b) is applied to the surface of the substrate (1), and subjected to curing. These steps may be carried out in the opposite order, i.e. primer composition B may be applied before primer composition A, or they may be carried out simultaneously, with simultaneous curing In additional steps, primer composition A (2a) is applied on the surface of primer composition B (2b), in the form of an indicium and cured, and primer composition B (2b) is applied on the surface of primer composition A (2a), in the form of an indicium and cured. The cholesteric liquid crystal precursor composition (3) is applied overtop of primer layers A (2a) and B (2b), and subjected to polymerization.

[0182] Figure 2a shows a cross-section view of a security feature of the invention. The substrate (1 ) is dark or black on its surface. According to step (3) of the method of the invention, primer composition A (2a) is applied to the surface of the substrate and subjected to curing. Primer composition B (2b) is applied overtop of primer composition such that the disposition of primer composition A (2a) forms one or more indicia, in this case, in the form of a six-stripe indicium and primer composition B (2b) forms one or more indicia, in this case, in the form of a five-stripe indicium, when viewed face-on. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye. The one or more indicia are invisible at this point, and will only be revealed when a cholesteric liquid crystal precursor composition is applied overtop to form the layer comprising the CLCP (3). In step (7) of the invention, the cholesteric liquid crystal precursor composition (3) is applied overtop of the primer layers A (2a) and B (2b), then heated and polymerized.

[0183] Figure 2b shows a face-on view of the security feature of Figure 2a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B.

[0184] Figure 3a depicts a cross-section view of a security feature of the invention. The substrate (1) is dark or black on its surface. According to step (3) of the method of the invention, primer composition A (2a) is applied to the surface of the substrate and subjected to curing. Primer composition B (2b) is applied to the substrate, such that the disposition of primer composition A (2a) forms an indicium in the form of a rectangle and primer composition B (2b) forms an indicium in the form of a rectangle, when viewed face-on. The primer compositions are cured using UV-VIS-light. These steps may be carried out in the opposite order, i.e. primer composition B may be applied before primer composition A, or they may be carried out simultaneously, with simultaneous curing. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye. The rectangle indicia are invisible at this point, and will only be revealed when a cholesteric liquid crystal precursor composition is applied overtop.

[0185] The cholesteric liquid crystal precursor composition (3) is applied overtop of the primer layers A (2a) and B (2b), in this case in the form of a rectangle indicium (3), when viewed face-on. It is then heated and polymerized.

[0186] Figure 3b shows a face-on view of the security feature of Figure 3a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B. The background is black because the substrate is black, the primer layers A and B are transparent or translucent, and CLCP has been applied in the form of a rectangle indicium that does not fully cover the substrate. Color is the result of reflection of the CLCP layer on top of the primer layers A and B.

[0187] Figure 4a depicts a cross-section view of a security feature of the invention. The substrate (1) is dark or black on its surface. According to step (3) of the method of the invention, primer composition A (2a) is applied to a first zone of the surface of the substrate and subjected to curing. Primer composition B (2b) is applied to a second zone, such that the disposition of primer composition A (2a) forms an indicium in the form of a rectangle and primer composition B (2b) forms an indicium in the form of a rectangle, when viewed face-on. The primer compositions are cured using UV-VIS-light. These steps may be carried out in the opposite order, i.e. primer composition B may be applied before primer composition A, or they may be carried out simultaneously, with simultaneous curing. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye. The rectangle indicia are invisible at this point, and will only be revealed when a cholesteric liquid crystal precursor composition is applied overtop.

[0188] The cholesteric liquid crystal precursor composition (3) is applied overtop the primer layer A (2a) and / or overtop the primer layer B (2b), in this case in the form of a three-stripe indicium (3), when viewed face- on. It is then heated and polymerized.

[0189] Figure 4b shows a face-on view of the security feature of Figure 4a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B. The background is black because the substrate is black, the primer layer is transparent or translucent, and CLCP has been applied in the form of a three-stripe indicium that does not fully cover the substrate. Color is the result of reflection of the CLCP layer on top of the primer layers A and / or B.

[0190] Figure 5a depicts a cross-section view of a security feature of the invention. The substrate (1) is dark or black on its surface. According to step (3) of the method of the invention, primer composition A (2a) is applied to a first zone of the surface of the substrate and subjected to curing. In this case zone of primer composition A is a rectangle that covers the entire surface of the substrate (1). Primer composition B (2b) is applied to a second zone, which in this case overlaps with the first zone, such that the disposition of primer composition A (2a) forms an indicium in the form of a rectangle and primer composition B (2b) forms an indicium in the form of a rectangle, when viewed face-on. The primer compositions are cured using UV-VIS-light. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye. The rectangle indicia are invisible at this point, and will only be revealed when a cholesteric liquid crystal precursor composition is applied overtop.

[0191] The cholesteric liquid crystal precursor composition (3) is applied overtop the primer layer A (2a) and / or overtop the primer layer B (2b), in this case in the form of a three-stripe indicium (3). It is then heated and polymerized.

[0192] Figure 5b shows a face-on view of the security feature of Figure 5a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B. The background is black because the substrate is black, the primer layers A and B are transparent or translucent, and CLCP has been applied in the form of a three-stripe indicium that does not fully cover the substrate. Color is the result of reflection of the CLCP layer on top of the primer layers A and / or B.

[0193] Security feature

[0194] The invention provides a security feature obtainable by or made by the method of the invention.

[0195] In one aspect, the invention provides a security feature comprising:

[0196] (1) the substrate described herein;

[0197] (2) the primer layer described herein on the surface of the substrate, optionally in the form of one or more indicia;

[0198] (3) the layer comprising the cholesteric liquid crystal polymer ("CLCP layer”) described herein on the surface of the primer layers, which CLCP layer may optionally be in the form of one or more indicia; wherein the primer layer comprises a first primer A, which, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ1, a second primer B, which, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ2, wherein Δλr= λ2- λ1≥ 5 nm, and wherein at least a portion of the CLCP layer overlaps at least partially primer A and at least a portion of the CLCP layer overlaps at least partially primer B; wherein the primer A results from curing of the first UV-VIS-curable primer composition A, and the first UV-VIS-curable primer composition A comprises less than at or about 20 wt%, based on the total weight of the primer composition, of aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, and the primer B results from curing of the second UV-VIS-curable primer composition B, and the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3.

[0199] Preferred examples of the various components of the security feature are as stated for the method of the invention.

[0200] Examples of security features of the invention are illustrated schematically in Figures 1-5. One embodiment of the security feature of the invention is depicted schematically in cross-section view in Figure 2a, where (1) designates the substrate, (2a) designates a layer of cured primer composition A, (2b) designates a layer of cured primer composition B, wherein primer composition A forms a six- stripe indicium and primer composition B forms a five-stripe indicium, when viewed face-on. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye. (3) designates the CLCP layer, which is in the form of a rectangle that entirely covers the five-stripe indicium.

[0201] Figure 2b shows a face-on view of the security feature of Figure 2a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B.

[0202] Figure 3a depicts a cross-section view of a security feature of the invention. The substrate (1) is preferably dark or black on its surface. Cured primer composition A (2a) is in a first zone of the surface of the substrate, cured primer composition B (2b) is in a second zone, such that the disposition of cured primer composition A (2a) forms an indicium in the form of a rectangle and cured primer composition B (2b) forms an indicium in the form of a rectangle, when viewed face-on. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye.

[0203] The cholesteric liquid crystal polymer layer (3) is on top of the primer layer, in this case in the form of a rectangle indicium (3) that straddles the first zone (primer A) and the second zone (primer B).

[0204] Figure 3b shows a face-on view of the security feature of Figure 3a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B. The background is black because the substrate is black, the primer layer is transparent or translucent, and CLCP has been applied in the form of a rectangle indicium that does not fully cover the substrate. Color is the result of reflection of the CLCP layer on top of the primer layer.

[0205] Figure 4a depicts a cross-section view of a security feature of the invention. The substrate (1) is preferably dark or black on its surface. Cured primer composition A (2a) is in a first zone of the surface of the substrate. Cured primer composition B (2b) is in a second zone, such that the disposition of cured primer composition A (2a) forms an indicium in the form of a rectangle and cured primer composition B (2b) forms an indicium in the form of a rectangle, when viewed face-on. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye.

[0206] The cholesteric liquid crystal polymer (3) sits on top of the primer layers (2a) and (2b), in this case in the form of a three-stripe indicium (3).

[0207] Figure 4b shows a face-on view of the security feature of Figure 4a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B. The background is black because the substrate is black, the primer layer is transparent or translucent, and CLCP has been applied in the form of a three-stripe indicium that does not fully cover the substrate. Color is the result of reflection of the CLCP layer on top of the primer layer.

[0208] Figure 5a depicts a cross-section view of a security feature of the invention. The substrate (1) is preferably dark or black on its surface. Cured primer composition A (2a) is in a first zone of the surface of the substrate. In this case the zone of cured primer composition A (2a) is a rectangle that covers the entire surface of the substrate (1). Cured primer composition B (2b) is in a second zone, which in this case overlaps with the first zone, such that the disposition of cured primer composition A (2a) forms an indicium in the form of a rectangle and cured primer composition B (2b) forms an indicium in the form of a rectangle, when viewed face-on. For the purposes of this illustration, the primer compositions are depicted as if they have a color, whereas in practice they are usually transparent or translucent, and do not appear different from one another to the naked eye.

[0209] The cholesteric liquid crystal polymer (3) is on top of primer layers (2a) and (2b), in this case the CLCP layer is in the form of a three-stripe indicium (3), when viewed face-on.

[0210] Figure 5b shows a face-on view of the security feature of Figure 5a. Zones designated with λ1have the color of cholesteric liquid crystal polymer in contact with primer A. Zones designated with λ2have the color of cholesteric liquid crystal polymer in contact with primer B. The background is black because the substrate is black, the primer layer is transparent or translucent, and CLCP has been applied in the form of a three-stripe indicium that does not fully cover the substrate. Color is the result of reflection of the CLCP layer on top of the primer layer.

[0211] Preferred embodiments of the invention

[0212] 1 . A method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer B, the method comprising the steps:

[0213] (1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;

[0214] (2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1≥ 5 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B;

[0215] (3) applying the first UV-VIS-curable primer composition A to the substrate, optionally in the form of one or more indicia;

[0216] (4) curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0217] (5) applying the second UV-VIS-curable primer composition B to the substrate and / or to a portion of the primer layer A, optionally in the form of one or more indicia;

[0218] (6) curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0219] OR

[0220] (3') applying the second UV-VIS-curable primer composition B to the substrate, optionally in the form of one or more indicia;

[0221] (4') curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0222] (5') applying the first UV-VIS-curable primer composition A to the substrate and / or to a portion of the primer layer B, optionally in the form of one or more indicia;

[0223] (6') curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0224] (7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquid crystal monomer, at least one chiral liquid crystal monomer, at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;

[0225] (8) heating to remove the at least one solvent; and

[0226] (9) polymerizing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

[0227] 2. A method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the cholesteric liquid crystal precursor composition at least partially overlaps primer layer B, the method comprising the steps:

[0228] (1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;

[0229] (2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ15 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B;

[0230] (3) applying the first UV-VIS-curable primer composition A to the substrate, optionally in the form of one or more indicia;

[0231] (4) curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0232] (5) applying the second UV-VIS-curable primer composition B to the substrate and / or to a portion of the primer layer A, optionally in the form of one or more indicia;

[0233] (6) curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0234] (7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquid crystal monomer, at least one chiral liquid crystal monomer, at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;

[0235] (8) heating to remove the at least one solvent; and

[0236] (9) curing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

[0237] 3. A method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the cholesteric liquid crystal precursor composition at least partially overlaps primer layer B, the method comprising the steps:

[0238] (1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;

[0239] (2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1≥ 5 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B;

[0240] (3') applying the second UV-VIS-curable primer composition B to the substrate, optionally in the form of one or more indicia; (4') curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0241] (5') applying the first UV-VIS-curable primer composition A to the substrate and / or to a portion of the primer layer B, optionally in the form of one or more indicia;

[0242] (6') curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0243] (7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquid crystal monomer, at least one chiral liquid crystal monomer, at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;

[0244] (8) heating to remove the at least one solvent; and

[0245] (9) polymerizing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

[0246] 4. A method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the cholesteric liquid crystal precursor composition at least partially overlaps primer layer B, the method comprising the steps:

[0247] (1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;

[0248] (2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1≥ 5 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B;

[0249] (3) applying the first UV-VIS-curable primer composition A to the substrate, optionally in the form of one or more indicia;

[0250] (4) curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0251] (5) applying the second UV-VIS-curable primer composition B to the substrate and / or to a portion of the primer layer A, optionally in the form of one or more indicia;

[0252] (6) curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B; OR

[0253] (3') applying the second UV-VIS-curable primer composition B to the substrate, optionally in the form of one or more indicia;

[0254] (4') curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0255] (5') applying the first UV-VIS-curable primer composition A to the substrate and / or to a portion of the primer layer B, optionally in the form of one or more indicia;

[0256] (6') curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0257] (7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquid crystal monomer, which is 2-methylbenzene-1 ,4-diyl bis[4-({[4- (acryloyloxy)butoxy]carbonyl}oxy)benzoate], and at least one chiral liquid crystal monomer, which is D- glucitol-1 ,4:3, 6-dianhydro-bis[4-[[4-[[[4-[(1 -oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate], at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;

[0258] (8) heating to remove the at least one solvent; and

[0259] (9) polymerizing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

[0260] 5. A method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the cholesteric liquid crystal precursor composition at least partially overlaps primer layer B, the method comprising the steps:

[0261] (1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;

[0262] (2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1 ≥ 5 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B; (3) applying the first UV-VIS-curable primer composition A to the substrate, optionally in the form of one or more indicia;

[0263] (4) curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0264] (5) applying the second UV-VIS-curable primer composition B to the substrate and / or to a portion of the primer layer A, optionally in the form of one or more indicia;

[0265] (6) curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;

[0266] (7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquid crystal monomer, which is 2-methylbenzene-1 ,4-diyl bis[4-({[4- (acryloyloxy)butoxy]carbonyl}oxy)benzoate], and at least one chiral liquid crystal monomer, which is D- glucitol-1 ,4:3, 6-dianhydro-bis[4-[[4-[[[4-[(1 -oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate], at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;

[0267] (8) heating to remove the at least one solvent; and

[0268] (9) polymerizing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

[0269] 6. A method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the cholesteric liquid crystal precursor composition at least partially overlaps primer layer B, the method comprising the steps:

[0270] (1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;

[0271] (2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1≥ 5 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B;

[0272] (3') applying the second UV-VIS-curable primer composition B to the substrate, optionally in the form of one or more indicia;

[0273] (4') curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B; (5') applying the first UV-VIS-curable primer composition A to the substrate and / or to a portion of the primer layer B, optionally in the form of one or more indicia;

[0274] (6') curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;

[0275] (7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquid crystal monomer, which is 2-methylbenzene-1 ,4-diyl bis[4-({[4- (acryloyloxy)butoxy]carbonyl}oxy)benzoate], and at least one chiral liquid crystal monomer, which is D- glucitol-1 ,4:3, 6-dianhydro-bis[4-[[4-[[[4-[(1 -oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate], at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;

[0276] (8) heating to remove the at least one solvent; and

[0277] (9) polymerizing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

[0278] 7. A security feature comprising:

[0279] (1) a substrate;

[0280] (2) a first primer A and a second primer B, wherein:

[0281] (2a) the first primer A is in contact with the surface of the substrate, and the second primer B is in contact with a portion of the surface of primer A and / or the surface of the substrate;

[0282] AND / OR

[0283] (2b) the second primer B is in contact with the surface of the substrate and the first primer A is in contact with a portion of the surface of primer B and / or the surface of the substrate; wherein the first primer A and / or the second primer B are optionally in the form of one or more indicia;

[0284] (3) a layer comprising a cholesteric liquid crystal polymer, which layer may optionally be in the form of one or more indicia, in contact with at least a portion of the surface of the primer layer A and the primer layer B; wherein the first primer A, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer is λ1, the second primer B, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1≥ 5 nm; wherein the first primer A results from curing of a first a first UV-VIS-curable primer composition A, which comprises less than at or about 20 wt%, based on the total weight of the first primer composition A, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, and the second primer B results from curing of a second UV-VIS-curable primer composition B, which comprises greater than or equal to at or about 20 wt%, based on the total weight of the second primer composition B, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3.

[0285] 8. A security feature comprising: (1) a substrate;

[0286] (2) a first primer A and a second primer B, wherein:

[0287] (2a) the first primer A is in contact with the surface of the substrate, and the second primer B is in contact with a portion of the surface of primer A and / or the surface of the substrate; AND / OR

[0288] (2b) the second primer B is in contact with the surface of the substrate and the first primer A is in contact with a portion of the surface of primer B and / or the surface of the substrate; wherein the first primer A and / or the second primer B are optionally in the form of one or more indicia;

[0289] (3) a layer comprising a cholesteric liquid crystal polymer, which layer may optionally be in the form of one or more indicia, in contact with at least a portion of the surface of the primer layer A and the primer layer B; wherein the first primer A, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ1, the second primer B, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ2, wherein Δλr= λ2- λ1≥ 5 nm; wherein the first primer A results from curing of a first a first UV-VIS-curable primer composition A, which comprises less than at or about 20 wt%, based on the total weight of the first primer composition A, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, and the second primer B results from curing of a second UV-VIS-curable primer composition B, which comprises greater than or equal to at or about 20 wt%, based on the total weight of the second primer composition B, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, and wherein the cholesteric liquid crystal polymer layer is made by polymerizing a cholesteric liquid crystal precursor solution comprising 2- methylbenzene-1,4-diylbis[4-({[4-

[0290] (acryloyloxy)butoxy]carbonyl}oxy)benzoate], and D-g lucitol- 1 ,4:3,6-dianhydro-bis[4-[[4-[[[4-[(1 -oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate].

[0291] 9. Any one preceding embodiment, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B comprise radically-curable components, cationically- curable components, or mixtures of both, more preferably wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B comprise radically-curable components.

[0292] 10. Any one preceding embodiment, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B independently comprise one or more oligomeric UV-VIS- curable components, preferably one or more oligomeric acrylates, different from the aliphatic polyurethane acrylate oligomer having acrylate functionality of less than 3.

[0293] 11 . Any one preceding embodiment, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B independently comprise acrylates having acrylate functionalities of 1, 2, 3 and greater, different from the aliphatic polyurethane acrylate oligomer having acrylate functionality of less than 3.

[0294] 12. Any one preceding embodiment, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B independently comprise at least one oligomer selected from epoxy-based acrylates, such as bisphenol A epoxy resin end-capped with acrylate groups, acrylated oligoamine resins, polyether-based acrylate resins, polyester-based acrylate resins, polyurethane-based acrylate resins different from the aliphatic polyurethane acrylate oligomer having acrylate functionality of less than 3, and mixtures of these.

[0295] 13. Any one preceding embodiment, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B independently comprise 2-hydroxy-1-[4-[4-(2-hydroxy-2- methylpropionyl)phenoxy]phenyl]-2-methylpropanone, as photoinitiator.

[0296] 14. Any one preceding embodiment, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B independently comprise at least one polyether acrylate oligomer.

[0297] 15. Any one preceding embodiment, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B independently comprise an oligomer that is an amine- modified acrylate, more preferably an amine-modified acrylate together with glycerol propoxylate triacrylate and trimethylolpropane triacrylate.

[0298] 16. Any one preceding embodiment, wherein both the one or more nematic compounds and the one or more chiral liquid crystal monomers comprise at least one curable group, preferably a group that is able to take part in a free radical polymerization and in particular, an unsaturated carbon-carbon bond such as for example an acrylate group with formula H2C=CH-C(O)-O or H2C=C(CH3)-C(O)-O.

[0299] 17. Any one preceding embodiment, wherein the cholesteric liquid crystal precursor composition comprises 2-hydroxy-1-[4-[4-(1-hydroxy-2-methylpropanoyl)phenoxy]phenyl]-2- methylpropan-1-one as photoinitiator, preferably at at or about 0.7-2.5 wt%, more preferably at at or about 0.8-1 .5 wt%, based on the total weight of the cholesteric liquid crystal precursor composition.

[0300] EXAMPLES

[0301] Examples of primer compositions for use in the method of the invention

[0302] The following primer compositions exemplify those that can be used in the method of the invention. When in contact with a CLCP layer, each of the cured primers induces a particular reflection wavelength in the CLCP layer. Different primer composition pairs may be chosen as the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B to achieve the desired effect in the final security feature. In general, the bigger the difference in face reflection wavelength between two primers (Δλr), the more striking the effect when used in the method of the invention.

[0303] Ingredients used in the Examples are listed in Table 1 .

[0304] Primer compositions

[0305] Primer compositions A1-A11 and B1-B10 were prepared using the ingredients listed in Tables 2 and 3, as follows: The ingredients were mixed and dispersed at room temperature using a high-speed mixer (DISPERMAT LC-2), for 20 minutes at 1,500 rpm.

[0306] The viscosities of the primer compositions A11 and B10 were determined at 25°C using a Brookfield viscosimeter (model “RVDV-I Prime”), spindle 21 at 100 rpm for 20 and spindle 28 at 100 rpm for 21. The measured viscosities and the absence of fillers in primer compositions A11 and B10 make them particularly suited to printing with flexography or rotogravure processes.

[0307] The viscosities of primer compositions A1-A10 and B1-B9 were determined at 25°C and 500s-1using an Anton Paar MCR92 portable viscosimeter. The measured viscosity as well as the presence of fillers in in these primer compositions makes them suitable for offset printing.

[0308]

[0309]

[0310] Cholesteric liquid crystal polymer (CLCP) precursor composition

[0311] The cholesteric liquid crystal precursor composition was prepared using the ingredients listed in Table 4, as follows: the solvent was poured in a 200 ml bottle, the nematic monomer and the chiral monomer were added and the bottle was kept in an ultrasonic bath for about 30 minutes at 40°C in order to dissolve the ingredients in the solvent. The mixture was then poured in a high-speed mixer (Dispermat LC-2), the photoinitiator was added and dispersed for 20 minutes at 2000 rpm. Finally, the surfactant was added and mixing was continued for a further 5 minutes at 1500 rpm.

[0312] The viscosity of the cholesteric liquid crystal precursor composition was measured at 25°C using a DIN 4” cup, the values being converted to mPas using a viscosity conversion table provided by Saint Clair Systems (Washington, USA). The measured viscosity indicates that the exemplified cholesteric liquid crystal precursor composition is suitable for printing with flexography or gravure processes.

[0313] Optical samples

[0314] Optical samples were made to evaluate the face reflection wavelength of a CLCP layer deposited overtop of the cured primer compositions using primer compositions A1-A11 and B1-B10, and the cholesteric liquid crystal precursor composition, as follows: a) The primer compositions A1-A11 and B1-B10 were independently applied vertically on black / white Leneta cards (Leneta Inc., Form N2C-2, 194 x 260mm) using a semi-automatic laboratory coater (K101 Control Coater, RK Print) equipped with a coating bar HC0 (nominal thickness 4pm) to form a rectangle of approx. 18 cm x 4 cm. The so-obtained primer composition layers were independently cured using a mercury UV-VIS-curing device (Technigraf Aktiprint Mini 18-2, two medium- pressure mercury lamps, total power 80 W / cm, one pass at a constant speed of 90 mm / s corresponding to an exposure time of about 0.5 sec) to generate the cured primer layer.

[0315] The result was a series of cards with a cured primer compositions A1-A11 and B1-B10 applied thereto. b) the cholesteric liquid crystal precursor composition (Table 4) was then independently applied overtop of the primer layers obtained in step a) using the same semi-automatic coater equipped with a coating bar HC1 (theoretical thickness 6 pm), as a rectangle of approximately 18cm x 4cm centered on the black part of the Leneta card. The applied cholesteric liquid crystal precursor composition was then dried in a hot air oven at a temperature of 50°C for 30 seconds to evaporate the solvent and generate the cholesteric liquid crystal state. Finally, the still liquid cholesteric liquid crystal layer was polymerized using the mercury UV-VIS-curing device described at step a) with the same settings to generate a cholesteric liquid crystal polymer (CLCP) layer overtop of the primers A1-A11 and B1-B10.

[0316] Optical properties of samples

[0317] The following optical properties were independently recorded for each of the cards: a) Maximum wavelength [nm] of selective reflection at face angle: a UV-Vis- spectrum (360 - 700 nm) was recorded using a Datacolor 650 spectrophotometer (parameters: integration sphere, diffuse illumination (pulse xenon D65) and 10° viewing, analyzer SP2000 with dual 256 diode array for the wavelength range 360-700 nm, emission aperture 9 mm, detection aperture 5 mm) with a precision of ± 5 nm. The maximum wavelength of selective reflection (i.e. the wavelength at which the reflection reached its maximum value) was derived therefrom and is reported in Tables 2 and 3. b) Reflectance [%]: the amount of light reaching the detector at the maximum wavelength of selective reflection obtained under a) was compared to the amount of emitted light at the same wavelength, determined using a white reflecting calibration standard. Since the CLCP layer completely absorbs one of the two circularly polarized components, the maximal possible reflectance is 50%. Reflectance is an indication of the “brightness” of the obtained color shift, i.e. a high reflectance results in bright, saturated colors whereas a low reflectance results in a dull appearance. The reflectance values were measured with the same device and the same observation parameters as the maximum wavelength of selective reflection under item a) and reported in Table 5, below. c) Color shifting properties: the CLCP layers were independently assessed for their color shifting behavior by first holding them vertically in front of the observer's eye and then slowly changing the observation angle from face angle (about 90°) to grazing angle (20-30°), noting down only the colors observed at both extremes. The results are reported in Table 5, below.

[0318] Results

[0319] The data in Tables 2 and 3 demonstrate that, for the CLCP system chosen, face reflection wavelengths of 560-600 nm are obtainable, merely by changing the composition of the underlying primer layer.

[0320] The shortest face reflection wavelength for a CLCP layer deposited on the primers resulting from curing of the primer compositions listed in Tables 2 and 3 is 560 nm (e.g. primer compositions A1-A11 , all of which comprise less than 20 wt% of an aliphatic polyurethane acrylate oligomer having a functionality of less than 3). The data show that addition of greater than or equal to 20 wt% of aliphatic polyurethane acrylate oligomers with acrylate functionalities less than 3 results in a shifting of the face reflection wavelength to longer wavelengths than 560 nm (“red-shift”), which is reported as Δλrwith respect to 560 nm.

[0321] For example, primer composition A1 has no polyurethane acrylate oligomer, and yields a face reflection wavelength of 560 nm for a deposited CLCP layer. Primer composition A2, which is similar in composition to primer composition A1, but contains 16.52 wt% (i.e. less than 20 wt%) of an aliphatic polyurethane acrylate oligomer having an acrylate functionality of 2, also yields a face reflection wavelength of 560 nm for the deposited CLCP layer (i.e. no red-shift). In contrast, when the content of aliphatic polyurethane acrylate oligomer having a functionality of 2 is increased to 28.17 wt%, as in primer compositions B2 and B3, the face reflection wavelength of the deposited CLCP layer is red- shifted to 575 nm and 570 nm, respectively (Δλr= 15 nm and 10 nm, respectively, with respect to primer compositions A1and A2).

[0322] The red-shift becomes larger as the concentration of aliphatic polyurethane acrylate oligomer having an acrylate functionality of less than 3 is increased. Primer compositions B3, B4, B5, B6 and B7, have contents of aliphatic polyurethane acrylate oligomer having an acrylate functionality of 2, of 28.17, 36.81, 43.48, 48.78 and 53.10 wt%, respectively, and the face reflection wavelengths of CLCP layers deposited thereon are 570, 580, 590, 595 and 600 nm, respectively. These face reflection wavelengths represent Δλr's (red-shifts) of 10, 20, 30, 35 and 40 nm, respectively, with respect to primer compositions A1 and A2.

[0323] Primer composition A3 (Δλr= 0) is similar in composition to primer composition B6 (Δλr= 35 nm), except that primer composition A3 comprises an aliphatic polyurethane acrylate oligomer having an acrylate functionality of 3, rather than 2 as in B6. The same is true of primer compositions A4 and A5, both of which comprise 48.78 wt% of aliphatic polyurethane acrylate oligomers having functionalities of 3, and which show no red-shift VS 560 nm. Similarly, primer composition A6, which comprises 48.78 wt% of an aliphatic polyurethane acrylate oligomer having an acrylate functionality of 4, shows no red-shift VS 560 nm. The lack of red-shift VS 560 nm in primer composition A3, A4 and A5, where the aliphatic polyurethane acrylate oligomer has an acrylate functionality of 3, and primer composition A6, where the aliphatic polyurethane acrylate oligomer has an acrylate functionality of 4, demonstrates that the red- shifting effect is particular to aliphatic polyurethane acrylate oligomers having an acrylate functionality of less than 3.

[0324] Primer composition A7 comprises 48.78 wt% of an aromatic polyurethane acrylate oligomer, with an acrylate functionality of 2, and shows a face reflection wavelength for a deposited CLCP layer of 560 nm, i.e. no red-shift with respect to primer compositions A1 and A2. In contrast, primer composition B6, which comprises 48 wt% of an aliphatic polyurethane acrylate oligomer having an acrylate functionality of 2, shows a face reflection wavelength for the deposited CLCP layer of 595 nm, i.e. a red-shift of 35 nm VS 560 nm. Similarly, primer composition A8 comprises 48.78 wt% of an aromatic polyurethane acrylate oligomer having an acrylate functionality of 3, and primer composition A9 comprises 48.78 wt% of an aromatic polyurethane acrylate oligomer having an acrylate functionality of 6, and both these primer compositions do not result in a red-shift VS 560 nm for the deposited CLCP layer. This demonstrates that aromatic polyurethane acrylate oligomers do not lead to red-shifting VS 560 nm, independent of the degree of acrylate functionality, and that the red-shifting effect is particular to aliphatic polyurethane acrylate oligomers having an acrylate functionality of less than 3.

[0325] One can use, for example, any one of primer compositions A1-A11 as the first UV-VIS-curable primer composition A, together with any one of primer compositions B1-B10 as the second UV-VIS-curable primer composition B in the method of the invention to produce a security feature of the invention. Exemplary pairs of primer compositions are listed in Table 6.

[0326] Security feature

[0327] An apple indicium security feature was produced using the method of the invention using primer compositions A1 (which contains 0 wt% of an aliphatic polyurethane acrylate oligomer having a functionality of less than 3) and B5 (which contains 43.48 wt% of an aliphatic polyurethane acrylate oligomer having a functionality of 2), and the cholesteric liquid crystal precursor composition, as follows: In a first example (Fig. 6a) : a) Primer composition A1 was applied vertically on a black Leneta card (Leneta Inc., Form N2C- 2, 194 x 260mm) using a semi-automatic laboratory coater (K101 Control Coater, RK Print) equipped with a coating bar HC0 (nominal thickness 4pm) to form a rectangular background. The primer composition A1 was cured using a mercury UV-VIS-curing device (Technigraf Aktiprint Mini 18-2, two medium-pressure mercury lamps, total power 80 W / cm, one pass at a constant speed of 90 mm / s corresponding to an exposure time of about 0.5 sec) to generate the cured primer layer A1 . An apple indicium was then printed overtop of the cured primer layer, using primer composition B5, by flatbed screen-printing using a 90T / 48W silkscreen frame (90T means 90 mesh per centimeter; 48W means nominal thread diameter of 48 microns). Primer composition B5 was cured using a mercury UV-VIS- curing device (Technigraf Aktiprint Mini 18-2, two medium-pressure mercury lamps, total power 80 W / cm, one pass at a constant speed of 90 mm / s corresponding to an exposure time of about 0.5 sec) to generate the cured primer layer B5 in the form of an apple indicium. b) the cholesteric liquid crystal precursor composition (Table 4) was then applied overtop of the primer layers obtained in step a) using the same semi-automatic coater equipped with a coating bar HC1 (theoretical thickness 6 pm), as a rectangle covering over primer layers A1 and B5. The applied cholesteric liquid crystal precursor composition was then dried in a hot air oven at a temperature of 50°C for 30 seconds to evaporate the solvent and generate the cholesteric liquid crystal state. Finally, the still liquid cholesteric liquid crystal layer was polymerized using the mercury UV-VIS-curing device described at step a) with the same settings to generate a cholesteric liquid crystal polymer (CLCP) layer overtop of the primers A1 and B5.

[0328] The resulting security feature is shown in Figure 6a, where λ1indicates areas that appear green, and λ2indicates areas that appear gold (Δλr= 15 nm).

[0329] In a second example (Fig. 6b): a) Primer composition B5 was applied vertically on a black Leneta card (Leneta Inc., Form N2C- 2, 194 x 260mm) using a semi-automatic laboratory coater (K101 Control Coater, RK Print) equipped with a coating bar HC0 (nominal thickness 4pm) to form a rectangular background. The primer composition B5 was cured using a mercury UV-VIS-curing device (Technigraf Aktiprint Mini 18-2, two medium-pressure mercury lamps, total power 80 W / cm, one pass at a constant speed of 90 mm / s corresponding to an exposure time of about 0.5 sec) to generate the cured primer layer B5. An apple indicium was then printed overtop of the cured primer layer, using primer composition A1, by flatbed screen-printing using a 90T / 48W silkscreen frame (90T means 90 mesh per centimeter; 48W means nominal thread diameter of 48 microns). Primer composition A1 was cured using a mercury UV-VIS- curing device (Technigraf Aktiprint Mini 18-2, two medium-pressure mercury lamps, total power 80 W / cm, one pass at a constant speed of 90 mm / s corresponding to an exposure time of about 0.5 sec) to generate the cured primer layer A1 in the form of an apple indicium. b) the cholesteric liquid crystal precursor composition (Table 4) was then applied overtop of the primer layers obtained in step a) using the same semi-automatic coater equipped with a coating bar HC1 (theoretical thickness 6 pm), as a rectangle covering over both primer layers B5 and A1 . The applied cholesteric liquid crystal precursor composition was then dried in a hot air oven at a temperature of 50°C for 30 seconds to evaporate the solvent and generate the cholesteric liquid crystal state. Finally, the still liquid cholesteric liquid crystal layer was polymerized using the mercury UV-VIS-curing device described at step a) with the same settings to generate a cholesteric liquid crystal polymer (CLCP) layer overtop of the primers A1 and B5.

[0330] The resulting security feature is shown in Figure 6b, where λ1indicates areas that appear green, and λ2indicates areas that appear gold (Δλr≈ 15 nm).

Claims

CLAIMS1. A method for producing a security feature on a substrate, wherein the security feature comprises a primer layer A, optionally in the form of one or more indicia, a primer layer B, optionally in the form of one or more indicia, and a layer comprising a cholesteric liquid crystal polymer, optionally in the form of one or more indicia, wherein at least part of the layer comprising the cholesteric liquid crystal polymer at least partially overlaps primer layer A and at least part of the layer comprising cholesteric liquid crystal polymer at least partially overlaps primer layer B, the method comprising the steps:(1) providing a first UV-VIS-curable primer composition A, which, when cured yields the primer layer A, wherein when primer layer A is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ1, wherein the first UV-VIS-curable primer composition A comprises less than at or about 20 wt% of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition A;(2) providing a second UV-VIS-curable primer composition B, which, when cured yields the primer layer B, wherein when primer layer B is in contact with the cholesteric liquid crystal polymer the face reflection wavelength of the cholesteric liquid crystal polymer is λ2, wherein Δλr= λ2- λ1≥ 5 nm, wherein the second UV-VIS-curable primer composition B comprises greater than or equal to at or about 20 wt% aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, based on the total weight of the UV-VIS-curable primer composition B; followed by steps (3), (4), (5) and (6), or alternatively steps (3'), (4'), (5') and (6'):(3) applying the first UV-VIS-curable primer composition A to the substrate, optionally in the form of one or more indicia;(4) curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A;(5) applying the second UV-VIS-curable primer composition B to the substrate and / or to a portion of the primer layer A, optionally in the form of one or more indicia;(6) curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;OR(3') applying the second UV-VIS-curable primer composition B to the substrate, optionally in the form of one or more indicia;(4') curing the UV-VIS-curable primer composition B using UV light, to produce the primer layer B;(5') applying the first UV-VIS-curable primer composition A to the substrate and / or to a portion of the primer layer B, optionally in the form of one or more indicia;(6') curing the UV-VIS-curable primer composition A using UV light, to produce the primer layer A; followed by:(7) applying a cholesteric liquid crystal precursor composition comprising at least one nematic liquidcrystal monomer, at least one chiral liquid crystal monomer, at least one UV-VIS-photoinitiator and at least one solvent, the nematic liquid crystal monomers and chiral liquid crystal monomers being capable of copolymerizing to form the layer comprising a cholesteric liquid crystal polymer, wherein at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer A and at least a portion of the cholesteric liquid crystal precursor composition at least partially overlaps primer B, and wherein the liquid crystal precursor composition is optionally in the form of one or more indicia;(8) heating to remove the at least one solvent; and(9) polymerizing the cholesteric liquid crystal precursor composition using UV light to produce the layer comprising the cholesteric liquid crystal polymer, optionally in the form of one or more indicia.

2. The method of claim 1, wherein the first UV-VIS-curable primer composition A and the second UV-VIS-curable primer composition B independently further comprise one or more acrylate monomers and oligomers, other than the aliphatic polyurethane acrylate oligomer having an acrylate functionality of less than 3.

3. The method of claim 1 or 2, wherein the layer comprising the layer comprising the cholesteric liquid crystal polymer is in the form of one or more indicia.

4. The method of claim 1 , 2 or 3, wherein the primer layer A and / or the primer layer B are in the form of one or more indicia.

5. The method of any one of claims 1 to 4, wherein the application of the first UV-VIS-curable primer composition A and the application of the second UV-VIS-curable primer composition B is carried out by a printing process, preferably selected from flexography printing processes, gravure printing processes, ink-jet printing processes, screen printing processes and offset printing processes.

6. The method of any one of claims 1 to 5, wherein the application of the second UV-VIS-curable precursor composition B in step (5) is a printing process, selected from flexography printing processes, gravure printing processes, ink-jet printing processes and screen-printing processes.

7. The method of any one of claims 1 to 6, wherein in the second UV-VIS-curable primer composition B, the at least one aliphatic polyurethane acrylate oligomer has an acrylate functionality of less than 2.5.

8. The method of any one of claims 1 to 7, wherein in the second UV-VIS-curable primer composition B, the at least one aliphatic polyurethane acrylate oligomer has an acrylate functionality of 2 or less.

9. The method of any one of claims 1 to 8, wherein the at least one nematic liquid crystal monomer is 2-methylbenzene-1 ,4-diyl bis[4-({[4-(acryloyloxy)butoxy]carbonyl}oxy)benzoate].

10. The method of any one of claims 1 to 9, wherein the at least one chiral liquid crystal monomer is D-Glucitol 1 ,4:3,6-dianhydro-bis[4-[[4-[[[4-[(1-oxo-2- propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate],11. A security feature obtainable or obtained by the method of any one of claims 1 to 10.

12. A security feature comprising:(1) a substrate;(2) a first primer A and a second primer B, wherein:(2a) the first primer A is in contact with the surface of the substrate, and the second primer B is in contact with a portion of the surface of primer A and / or the surface of the substrate; AND / OR(2b) the second primer B is in contact with the surface of the substrate and the first primer A is in contact with a portion of the surface of primer B and / or the surface of the substrate; wherein the first primer A and / or the second primer B are optionally in the form of one or more indicia;(3) a layer comprising a cholesteric liquid crystal polymer, which layer may optionally be in the form of one or more indicia, in contact with at least a portion of the surface of the primer layer A and the primer layer B; wherein the first primer A, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ1, the second primer B, when in contact with the cholesteric liquid crystal polymer results in a face reflection wavelength of the cholesteric liquid crystal polymer of λ2, wherein Δλr= λ2- λ1≥ 5 nm; wherein the first primer A results from curing of a first UV-VIS-curable primer composition A, which comprises less than at or about 20 wt%, based on the total weight of the first primer composition A, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3, and the second primer B results from curing of a second UV-VIS-curable primer composition B, which comprises greater than or equal to at or about 20 wt%, based on the total weight of the second primer composition B, of an aliphatic polyurethane acrylate oligomer with an acrylate functionality of less than 3.

13. The security feature according to claim 12, wherein the surface of the substrate is dark or black.

14. The security feature of claim 12 or 13, wherein the cholesteric liquid crystal polymer comprises at least one nematic liquid crystal monomer, which is 2-methylbenzene-1 ,4-diyl bis[4-({[4- (acryloyloxy)butoxy]carbonyl}oxy)benzoate],15. The security feature of claim 12, 13 or 14, wherein the cholesteric liquid crystal polymer comprises at least one chiral liquid crystal monomer, which is D-Glucitol 1,4:3,6-dianhydro-bis[4-[[4-[[[4- [(1-oxo-2-propenyl)oxy]butoxy]carbonyl]oxy]benzoyl]oxy]benzoate],