Composition for absorbing ultraviolet electromagnetic radiation, substrate comprising a coating and method for protecting a surface of a substrate

Abstract

The present invention relates to a composition for absorbing ultraviolet (UV) electromagnetic radiation, wherein the composition comprises a UV absorbing agent and a film forming agent, wherein the UV absorbing agent is a compound Ar-Xn-R with Ar, X, n and R as defined in the specification, particularly the UV absorbing agent is cinnamic acid, cinnamyl alcohol or gallic acid, or a derivative thereof. The invention further relates to a substrate comprising a coating and a method for protecting a surface of a substrate from UV electromagnetic radiation.

Description

[0001] Composition for absorbing ultraviolet electromagnetic radiation, substrate comprising a coating and method for protecting a surface of a substrate

[0002] Field

[0003] The present invention relates to a composition for absorbing ultraviolet electromagnetic radiation, a substrate comprising a coating and a method for protecting a surface of a substrate.

[0004] The ultraviolet (UV) fraction from solar electromagnetic radiation is well-known to cause damage to surfaces such as for example wood and plastics and can lead to chemical and mechanical breakdown. In case of wood, this is mainly due to the UV light-absorption properties of the biopolymer lignin, which leads to its degradation and consequently in conjunction with moisture-induced dimensional changes of the wood to the adhesion failure of most transparent wood coatings. For increased wood surface stability, UV-protective coatings are needed.

[0005] Benzophenone- and benzotriazole-based UV-absorbers dominate commercial organic UV- protecting varnishes. The UV absorbers are generally added to coating formulations based on petroleum-based polyurethane (PU), alkyds, acrylics, or vegetable oil. The main problems of the current commercial UV-protecting wood coatings are limited overall sustainability, use of UV stabilizers that are often toxic, especially to aquatic life and use of petroleum-based polymer systems.

[0006] The market for UV stabilizers is changing rapidly due to the ecological threats and toxicity posed by the UV-absorbers. For example, UV-328 (2-(2H-Benzotriazol-2-yl)-4,6-bis(2- methylbutan-2-yl)phenol) will be phased out by 2026. To solve this sustainability issue, alternatives have been proposed, but the main limitations for sustainable UV stabilizers are discoloration, the circumstance that UV-absorbers are often colored, decomposition over time, cost and upscaling.

[0007] There are also inorganic protection systems available on the market. These systems are for instance based on ZnO, TiC>2 or SiC>2. However, the inorganic particles are embedded in polymer matrices, which are not UV stable, resulting in short maintenance intervals. ZnO nanoparticles are the most common inorganic compounds used on wood, but dense coatings and additives are required for good UV protection, altering the wood’s aesthetics and sustainability. Based on this, it is subject of the present invention to provide a composition for absorbing ultraviolet electromagnetic radiation, a substrate comprising a coating and a method for protecting a surface of a substrate that each represent an improvement with respect to the aforementioned problems, in particular with respect to the UV absorption properties, sustainability and cost.

[0008] This objective is attained by the subject-matter of the independent claims of the present specification, with further advantageous embodiments described in the dependent claims, examples, figures and general description of this specification.

[0009] Summary of the Invention

[0010] A first aspect of the invention relates to a composition for absorbing ultraviolet (UV) electromagnetic radiation, wherein the composition comprises at least one UV absorbing agent and a film forming agent, characterized in that: the UV absorbing agent is a compound of formula I, or a salt thereof,

[0011] Ar-Xn-R (I), wherein

[0012] Ar is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R4, -N(R5)-R6and -CN, with R4, R5and R6being independently selected from H and Ci-6-alkyl,

[0013] X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2-alkenyl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R7, -N(R8)-R9and -CN, with R7, R8and R9being independently selected from H and Ci-6-alkyl,

[0014] R is selected from -C(=O)-R10, -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, -C(=O)-N(R14)- R15, -N(R16)-C(=O)-R17, with R10, R11, R12, R13, R14, R15, R16and R17being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl , Cs-e-cycloalkyl, wherein the C3- 6-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, n is 0 or 1 , particularly 1 , the film forming agent comprises, particularly consists of, a resin, the proportion of the UV absorbing agent is at least 10% in relation to the total weight of the composition, and wherein the UV absorbing agent is selected in such a way that it is compatible with the resin, particularly the UV absorbing agent is selected in such a way that the composition is homogenous, or the UV absorbing agent is selected in such a way that the composition forms a stable emulsion

[0015] A second aspect of the invention relates to a substrate, wherein at least one surface of the substrate comprises at least in a section a coating, wherein the coating is derived from the composition according to the first aspect of the invention.

[0016] A third aspect of the invention relates to a method for protecting a surface of a substrate from UV electromagnetic radiation, comprising the steps: providing the surface of the substrate, and coating the surface with a composition according to the first aspect of the invention.

[0017] Terms and definitions

[0018] General

[0019] For purposes of interpreting this specification, the following definitions will apply and whenever appropriate, terms used in the singular will also include the plural and vice versa. In the event that any definition set forth below conflicts with any document incorporated herein by reference, the definition set forth shall control.

[0020] The terms “comprising”, “having”, “containing”, and “including”, and other similar forms, and grammatical equivalents thereof, as used herein, are intended to be equivalent in meaning and to be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. For example, an article “comprising” components A, B, and C can consist of (i.e., contain only) components A, B, and C, or can contain not only components A, B, and C but also one or more other components. As such, it is intended and understood that “comprises” and similar forms thereof, and grammatical equivalents thereof, include disclosure of embodiments of “consisting essentially of’ or “consisting of.”

[0021] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure.

[0022] Reference to “about” a value or parameter herein includes (and describes) variations that are directed to that value or parameter per se. For example, description referring to “about X” includes description of “X.” As used herein, including in the appended claims, the singular forms “a”, “or” and “the” include plural referents unless the context clearly dictates otherwise.

[0023] "And / or" where used herein is to be taken as specific recitation of each of the two specified features or components with or without the other. Thus, the term "and / or" as used in a phrase such as "A and / or B" herein is intended to include "A and B," "A or B," "A" (alone), and "B" (alone). Likewise, the term "and / or" as used in a phrase such as "A, B, and / or C" is intended to encompass each of the following aspects: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0024] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art (e.g., in cell culture, molecular genetics, nucleic acid chemistry, hybridization techniques and biochemistry, organic synthesis). Standard techniques are used for molecular, genetic, and biochemical methods (see generally, Sambrook et al., Molecular Cloning: A Laboratory Manual, 4th ed. (2012) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. and Ausubel et al., Short Protocols in Molecular Biology (2002) 5th Ed, John Wiley & Sons, Inc.) and chemical methods.

[0025] Any patent document cited herein shall be deemed incorporated by reference herein in its entirety.

[0026] Specific definitions

[0027] In the context of the present invention, the term “resin” can particularly be understood as a natural or synthetic organic compound consisting of a noncrystalline or viscous liquid substance that can harden into a highly durable plastic-like material, either through intermolecular cohesive forces or by chemical-crosslinking to form a thermoplastic or thermoset. Physically, the resin preferably allows for a plasticization of the UV absorbing agent.

[0028] In the context of the present invention, the term “ultraviolet (UV) electromagnetic radiation” relates particularly to electromagnetic radiation with wavelengths in the range between 100 nm and 450 nm.

[0029] The term “composition” in the context of the present specification relates to a mixture comprising components as defined herein, e.g. a resin and a UV absorbing agent.

[0030] Particularly, the composition is a homogenous mixture without phase separation, or a stable emulsion.

[0031] If not specified otherwise, the term proportion or relates to the mass fraction or percentage by weight. The weight of a substance refers to the dry weight of said substance. A wording such as “a proportion between 20 and 30%” includes the lower and upper limit, i.e. 20% and 30%, respectively. Organic Chemistry

[0032] The formulae of the present specification follow the convention of organic chemistry to not show hydrogen atoms on carbon scaffolds. Carbon is tetravalent and bonds not shown are assumed to be hydrogen unless shown otherwise.

[0033] The term alkyl in the context of the present specification relates to a saturated linear or branched hydrocarbon. The term unsubstituted Cnalkyl when used herein in the narrowest sense relates to the moiety -CnH2n- if used as a bridge between moieties of the molecule, or - CnH2n+i if used in the context of a terminal moiety. In certain embodiments, alkyl is limited to linear alkyl.

[0034] The term C1-C4 alkyl in the context of the present specification relates to a saturated linear or branched hydrocarbon having 1 , 2, 3 or 4 carbon atoms. Non-limiting examples for a C1-C4 alkyl are methyl, ethyl, propyl, prop-2-enyl, n-butyl, 2-methylpropyl, tert-butyl, cyclo-butyl, cyclo-propyl, methyl-cyclo-propyl. In certain embodiments, a C1-C4 alkyl is a methyl, ethyl, propyl or butyl moiety.

[0035] A Cv-Ce alkyl in the context of the present specification relates to a saturated linear or branched hydrocarbon having 1 , 2, 3, 4, 5 or 6 carbon atoms. Non-limiting examples for a Ci-Ce alkyl include the examples given for C1-C4 alkyl above, and additionally n-pentyl, 2-methylbutyl, 3- methylbutyl, 1 ,1 -dimethylpropyl, 1 ,2-dimethylpropyl, 1 ,2-dimethylpropyl, cyclo-pentyl, cyclohexyl, methyl-cyclo-pentyl. In certain embodiments, a C5 alkyl is a pentyl or cyclopentyl moiety and a Ce alkyl is a hexyl or cyclohexyl moiety.

[0036] Where used in the context of chemical formulae, the following abbreviations may be used: Me is methyl CH3, Et is ethyl -CH2CH3, Prop is propyl -(C ^CHs (n-propyl, n-pr) or -CH(CH3)2 (iso-propyl, i-pr), but is butyl -C4H9, -(CH2)3CH3, -CHCH3CH2CH3, -CH2CH(CH3)2 or -C(CH3)3.

[0037] The term alkene in the context of the present specification relates to a hydrocarbon comprising a double bond. Unsubstituted alkene (alkenyl) is of formula -CH=CH- when being located intramolecularly, and of formula -CH=CH2 when being a terminal moiety. An unsubstituted alkene (alkenyl) consists of C and H only. A substituted alkene (alkenyl) may comprise substituents as defined herein. The term C2-4-alkenyl refers to a hydrocarbon comprising 2 to 4 carbon atoms and at least one double bond. Examples for Cs-alkenyl are -CH=CH-CH2-, - CH2-CH=CH-, -C(CH3)=CH-, -CH=C(CH3)-. Examples for C4-alkenyl are -CH=CH-CH=CH-, - CH=CH-CH2-CH2-, -CH2-CH=CH-CH2-, -CH2-CH2-CH=CH-, -C(CH3)=CH-CH2-, -CH2- CH=C(CH3)-, -C(CH2-CH3)=CH-, -CH=C(CH2-CH3)-, -C(CH3)=C(CH3)-. The term C2-4-alkenyl particularly relates to a linear hydrocarbon, particularly -CH=CH-, -CH=CH-CH2-, -CH2- CH=CH-, -CH=CH-CH=CH-, -CH=CH-CH2-CH2-, -CH2-CH=CH-CH2-, -CH2-CH2-CH=CH-, more particularly -CH=CH-, -CH=CH-CH2-, -CH2-CH=CH-, -CH=CH-CH2-CH2-, -CH2-CH=CH- CH2-, -CH2-CH2-CH=CH-. The term alkyne in the context of the present specification relates to a hydrocarbon comprising a triple bond. Unsubstituted alkyne is of formula -CEC- when being located intramolecularly, and of formula -CECH (-C2H) when being a terminal moiety. An unsubstituted alkyne (alkinyl) consists of C and H only. A substituted alkyne may comprise substituents as defined herein.

[0038] The term aryl in the context of the present specification relates to a cyclic aromatic C5-C10 hydrocarbon. Examples of aryl include, without being restricted to, phenyl and naphthyl. In certain embodiments, aryl is limited to phenyl.

[0039] The term heteroaryl in the context of the present specification relates to a cyclic aromatic C5- Ce hydrocarbon, wherein at least one carbon is replaced by a heteroatom (e.g. N, O, S). Examples for heteroaryl include, without being restricted to, pyrrole, thiophene, furan, imidazole, pyrazole, thiazole, oxazole, pyridine, pyrimidine, and thiazin.

[0040] The term pyrrolyl refers to being H or a C1-3 alkyl, particularly H or methyl, more particularly H.

[0041] The term pyrimidinyl refers to

[0042] Detailed of the Invention

[0043] The present invention aims to protect surfaces of materials such as wood and plastics from damages caused by electromagnetic radiation by using a sustainable and environmentally friendly coating. In case of wood, damages occur mainly due to the UV light-absorption properties of the biopolymer lignin, which leads to its degradation and consequently in conjunction with moisture-induced dimensional changes of the wood to the adhesion failure of most transparent wood coatings. For increased wood surface stability, UV-protective coatings are needed. The composition described below may be used as such coating. The composition comprises an UV absorbing agent that is naturally occurring and can be obtained at low costs. For instance, the UV absorber ethyl cinnamate is renewable and can be obtained from tree bark. Furthermore, the UV absorbing agents described herein are non-toxic, particularly with regard to aquatic life. When combined with a resin, care must be taken with regard to the compatibility between the UV absorbing agent and the film forming agent to achieve a composition that forms a homogenous film without negative effects such as phase separation, whereby a stable emulsion is equally suited for the purpose of the invention. Suitable resins such as shellac are made from renewable raw materials and are characterized by water- and moisture resistance properties. For instance, shellac is a resin deposited by the ladylac bug on the outer bark of wood and is a natural film former with good water- and moisture-resistance properties. When the composition described herein is applied on wood, a stable, highly transparent, colorless coat is obtained. The coatings described herein are neither persistent, bioaccumulative, nor toxic.

[0044] A first aspect of the invention relates to a composition for absorbing ultraviolet (UV) electromagnetic radiation, wherein the composition comprises at least one UV absorbing agent and a film forming agent, characterized in that: the UV absorbing agent is a compound of formula I, or a salt thereof, particularly a compound of formula I,

[0045] Ar-Xn-R (I), wherein

[0046] Ar is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R4, -N(R5)-R6and -CN, with R4, R5and R6being independently selected from H and Ci-6-alkyl,

[0047] X is a substituted or unsubstituted C2-4-alkenyl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R7, -N(R8)-R9and -CN, with R7, R8and R9being independently selected from H and Ci-6-alkyl,

[0048] R is selected from -C(=O)-R10, -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, -C(=O)-N(R14)-R15, - N(R16)-C(=O)-R17, with R10, R11, R12, R13, R14, R15, R16and R17being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl, Cs-e-cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, n is 0 or 1 , particularly 1 , the film forming agent comprises, particularly consists of, a resin, the proportion of the UV absorbing agent is at least 10% in relation to the total weight of the composition, and wherein the UV absorbing agent is selected in such a way that it is compatible with the resin, particularly the UV absorbing agent is selected in such a way that the composition is homogenous, or the UV absorbing agent is selected in such a way that the composition forms a stable emulsion.

[0049] In certain embodiments, the composition is homogenous.

[0050] In certain embodiments, Ar is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from Ci-6-alkyl and -O-R4, with R4being selected from H and Ci-6-alkyl.

[0051] In certain embodiments, Ar is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from Ci-3-alkyl, -O-R4, -N(R5)-R6and -CN, with R4, R5and R6being independently selected from H and Ci-3-alkyl.

[0052] In certain embodiments, Ar is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from Ci-3-alkyl and -O-R4, with R4, R5and R6being independently selected from H and Ci-3-alkyl.

[0053] In certain embodiments, Ar is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from -O-R4, with R4being selected from H and Ci-6-alkyl, particularly Ci-3-alkyl.

[0054] In certain embodiments, Ar is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from -OH and -O-CH3.

[0055] In certain embodiments, Ar is selected from a substituted or unsubstituted furyl, thienyl, pyrrolyl, phenyl, pyridyl and pyrimidinyl, wherein the one or more substituents are defined as described in the embodiments above.

[0056] In certain embodiments, Ar is selected from a substituted or unsubstituted furyl, pyrrolyl, phenyl, pyridyl and pyrimidinyl, wherein the one or more substituents are defined as described in the embodiments above. In certain embodiments, Ar is selected from a substituted or unsubstituted furyl, phenyl, pyridyl and pyrimidinyl, wherein the one or more substituents are defined as described in the embodiments above.

[0057] In certain embodiments, Ar is selected from a substituted or unsubstituted furyl, phenyl, pyridyl, wherein the one or more substituents are defined as described in the embodiments above.

[0058] In certain embodiments, Ar is selected from a substituted or unsubstituted furyl, phenyl, wherein the one or more substituents are defined as described in the embodiments above.

[0059] In certain embodiments, Ar is selected from a substituted or unsubstituted phenyl, pyridyl and pyrimidinyl, wherein the one or more substituents are defined as described in the embodiments above.

[0060] In certain embodiments, Ar is a substituted or unsubstituted phenyl or pyridyl, wherein the one or more substituents are defined as described in the embodiments above.

[0061] In certain embodiments, Ar is a substituted or unsubstituted phenyl, wherein the one or more substituents are defined as described in the embodiments above.

[0062] In certain embodiments, Ar is an unsubstituted phenyl.

[0063] In certain embodiments, Ar is a substituted or unsubstituted phenyl, or an unsubstituted 5- or 6-membered heteroaryl, wherein the one or more substituents are defined as described in the embodiments above, particularly the one or more substituents are selected from -OH and -OCH3.

[0064] In certain embodiments, Ar is a substituted or unsubstituted phenyl, or an unsubstituted 5- or 6-membered heteroaryl, wherein the heteroaryl is selected as described in one of the embodiments described above, and wherein the one or more substituents are defined as described in the embodiments above.

[0065] According to an embodiment of the invention, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2-alkenyl, wherein one or more substituents are selected from Ci-3-alkyl, -O- R7, -N(R8)-R9and -CN.

[0066] In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2- alkenyl, wherein one or more substituents are selected from Ci-6-alkyl, -N(R8)-R9and -CN.

[0067] In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2- alkenyl, wherein one or more substituents are selected from Ci-3-alkyl, -N(R8)-R9and -CN.

[0068] In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2- alkenyl, wherein one or more substituents are selected from Ci-2-alkyl, -N(R8)-R9and -CN. In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2- alkenyl, wherein one or more substituents are selected from methyl, -N(R8)-R9and -CN.

[0069] According to an embodiment of the invention, R7, R8and R9are independently selected from H and Ci-3-alkyl.

[0070] According to an embodiment of the invention, R7, R8and R9are independently selected from H and Ci-2-alkyl.

[0071] According to an embodiment of the invention, R7, R8and R9are independently selected from H and methyl.

[0072] In certain embodiments, R8and R9are H.

[0073] In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2- alkenyl, wherein one or more substituents are selected from methyl, -NH2 and -CN.

[0074] In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2- alkenyl, wherein X is substituted by one substituent.

[0075] In certain embodiments, X is a substituted or unsubstituted C2-3-alkenyl, wherein the one or more substituents are defined as described in the embodiments above.

[0076] In certain embodiments, X is unsubstituted.

[0077] In certain embodiments, X is selected from -CH=CH-, -CH=CH-CH2-, -CH2-CH=CH-, - CH=CH-CH=CH-, -CH=CH-CH2-CH2-, -CH2-CH=CH-CH2-, -CH2-CH2-CH=CH-.

[0078] In certain embodiments, X is selected from -CH=CH-, -CH=CH-CH2-, -CH2-CH=CH-, - CH=CH-CH2-CH2-, -CH2-CH=CH-CH2-, -CH2-CH2-CH=CH-.

[0079] In certain embodiments, X is selected from -CH=CH-, -CH=CH-CH2-, -CH=CH-CH=CH-, - CH=CH-CH2-CH2-.

[0080] In certain embodiments, X is selected from -CH=CH-, -CH=CH-CH2-, -CH=CH-CH2-CH2-.

[0081] In certain embodiments, X is selected from -CH=CH- and -CH=CH-CH2-.

[0082] In certain embodiments, X is -CH=CH-.

[0083] According to an embodiment of the invention, R is selected from -C(=O)-R10, -O-R11, -C(=O)- O-R12, -C(=O)-N(R14)-R15, with R10, R11, R12, R14and R15being defined as described above.

[0084] According to an embodiment of the invention, R is selected from -C(=O)-R10, -O-R11, -C(=O)- O-R12, with R10, R11, and R12being defined as described above.

[0085] According to an embodiment of the invention, R is selected from -O-R11, -C(=O)-O-R12, with R11and R12being defined as described above. According to an embodiment of the invention, R is -C(=O)-O-R12, with R12being defined as described above.

[0086] According to an embodiment of the invention, R10, R11, R12, R14and R15are independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl, Cs-e-cycloalkyl, wherein the C3-6- cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH.

[0087] In certain embodiments, R10, R11, R12, R14and R15are independently selected from H, C1-16- alkyl, C2-i6-alkenyl, C2-16 alkinyl, particularly from H, Ci-s-alkyl, C2-s-alkenyl, C2-s-alkinyl, more particularly from H, Ci-4-alkyl, C2-4-alkenyl, C2-4-alkinyl.

[0088] According to an embodiment of the invention, R10, R11, R12, R14and R15are independently selected from H and Ci-24-alkyl , particularly from H and Ci-16-alkyl, more particularly from H and Ci-s-alkyl, even more particularly from H, Ci-4-alkyl.

[0089] In certain embodiments, R is selected from -OH, -C(=O)-H, -C(=O)-OH, -C(=O)-O-C6 cycloalkyl, -C(=O)-O-Ci-i2-alkyl, -C(=O)-O-C2-i2-alkenyl, wherein the Ce cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH.

[0090] In certain embodiments, R is selected from -OH, -C(=O)-H, -C(=O)-OH, -C(=O)-O-Ci-i2-alkyl, -C(=O)-O-C2-i2-alkenyl.

[0091] In certain embodiments, R is selected from -C(=O)-H, -C(=O)-O-Ci-i2-alkyl, -C(=O)-O-C2-12- alkenyl.

[0092] In certain embodiments, R is selected from -C(=O)-H, -C(=O)-O-C2-i2-alkyl, -C(=O)-O-C2-12- alkenyl.

[0093] According to an embodiment of the invention, the UV absorbing agent is a compound of formula II, III or IV, particularly II or III, more particularly II, or a salt thereof, formula (II), (III), (IV), wherein R1is selected from H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkinyl, -O-R3, R2is selected from -O-R4, ON or Ci-Ce alkyl, -N(R5)-R6, R18is selected from-O-R3, -Ci-6-alkyl-O-R3, R19is selected from -O-R4, ON or Ci-Ce alkyl, -N(R5)-R6, R20is selected from H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkinyl, -O-R3, R21is selected from is selected from -O-R4, CN or Ci-Ce alkyl, -N(R5)-R6, with m, p or p being 0, 1 , 2, 3, 4 or 5. particularly 0, 1 , 2 or 3, wherein

[0094] R3is selected from H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkinyl, Cs-e-cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents - OH or -COOH,

[0095] R4is selected from H, C1-C3 alkyl,

[0096] R5and R6are independently selected from H and Ci-6-alkyl.

[0097] According to an embodiment of the invention, the UV absorbing agent is a compound of formula II, III or IV, particularly II or III, more particularly II.

[0098] In certain embodiments, R1is selected from H, C1-C16 alkyl, C2-C16 alkenyl, -O-R3, with R3being selected as described herein.

[0099] In certain embodiments, R1is selected from H and -O-R3, with R3being selected as described herein.

[0100] In certain embodiments, R1is defined as described above and R3is selected from H, C1-C16 alkyl, C2-C16 alkenyl, particularly C1-C16 alkyl, C2-C16 alkenyl, more particularly C2-C16 alkyl, C2-C16 alkenyl.

[0101] In certain embodiments, R1is defined as described above and R3is selected from H, C1-C12 alkyl, C2-C12 alkenyl, particularly C1-C12 alkyl, C2-C12 alkenyl, more particularly C2-C12 alkyl, C2-C12 alkenyl.

[0102] In certain embodiments, R1is defined as described above and R3is selected from H, Ci-Cs alkyl, C2-C10 alkenyl, particularly Ci-Cs alkyl, C2-C10 alkenyl, more particularly C2-C8 alkyl, C2- C10 alkenyl.

[0103] In certain embodiments, R1is defined as described above and R3is selected from H, Ci-Ce alkyl, C2-C6 alkenyl, particularly Ci-Ce alkyl, C2-C6 alkenyl, more particularly C2-C6 alkyl, C2- Ce alkenyl.

[0104] In certain embodiments, R2is -O-R4, with R4being defined as described herein.

[0105] In certain embodiments, R2is as defined above and R4is H or methyl.

[0106] In certain embodiments, m is 0.

[0107] In certain embodiments, R18is -O-R3or -Ci-3-alkyl-O-R3, particularly -O-R3or -CH2-O-R3with R3being selected as described herein. In certain embodiments, R18is as defined above and R3is selected from H, C1-C16 alkyl, C2- C16 alkenyl, particularly H, Ci-Ce alkyl, C2-C6 alkenyl, more particularly H, C1-C3 alkyl, C2-C4 alkenyl.

[0108] In certain embodiments, R18is as defined above and R3is H.

[0109] In certain embodiments, R19is -O-R4.

[0110] In certain embodiments, R19is as defined above and R4is H or methyl.

[0111] In certain embodiments, q is 0.

[0112] In certain embodiments, R20is selected from H, C1-C16 alkyl, C2-C16 alkenyl, -O-R3, with R3being selected as described herein.

[0113] In certain embodiments, R20is selected from H, -O-R3, with R3being selected as described herein.

[0114] In certain embodiments, R20is -O-R3, with R3being selected as described herein.

[0115] In certain embodiments, R2is as defined above and R4is H or methyl.

[0116] In certain embodiments, p is 1 , 2 or 3, particularly 2 or 3.

[0117] In certain embodiments, R5and R6are independently selected from H and Ci-3-alkyl, particularly H and methyl, more particularly H.

[0118] In certain embodiments, R3is selected from H, C1-C16 alkyl, C2-C16 alkenyl.

[0119] In certain embodiments, the UV absorbing agent is selected from a c / s and / or trans isomer, particularly trans isomer, of cinnamic acid, cinnamaldehyde, sinapinic acid (also named sinapic acid), coumaric acid, ferulic acid, caffeic acid, chlorogenic acid, methyl cinnamate, ethyl cinnamate, allyl cinnamate, isobutyl cinnamate, pentyl cinnamate, heptyl cinnamate, citronellyl cinnamate, ammonium cinnamate, ammonium sinapate, ethyl 3-phenylbut-2- enoate, 3-amino-3-phenyl-acrylic acid ethyl ester, ethyl 3-(pyridin-2-yl)acrylate, ethyl (2)-3- (furan-2-yl)prop-2-enoate, ethyl 2-cyano-3-(2-furanyl)acrylate, cinnamyl alcohol, gallic acid, gallic acid ethyl ester, syringic acid, vanillic acid, protocatechuic acid.

[0120] In certain embodiments, the UV absorbing agent is selected from a cis and / or trans isomer, particularly trans isomer, of cinnamic acid, cinnamaldehyde, sinapinic acid (also named sinapic acid), coumaric acid, ferulic acid, caffeic acid, chlorogenic acid, methyl cinnamate, ethyl cinnamate, allyl cinnamate, isobutyl cinnamate, pentyl cinnamate, heptyl cinnamate, citronellyl cinnamate, ethyl 3-phenylbut-2-enoate, 3-amino-3-phenyl-acrylic acid ethyl ester, ethyl 3-(pyridin-2-yl)acrylate, ethyl (2)-3-(furan-2-yl)prop-2-enoate, ethyl 2-cyano-3-(2- furanyl)acrylate, cinnamyl alcohol, gallic acid, gallic acid ethyl ester, syringic acid, vanillic acid, protocatechuic acid. In certain embodiments, the UV absorbing agent is a trans isomer of a compound as defined herein.

[0121] The trans isomers are shown in the following: Cinnamic acid

[0122] Cinnamaldehyde

[0123] Sinapinic acid (also named sinapic acid)

[0124] Coumaric acid , particularly p-coumaric acid

[0125] Ferulic acid Caffeic acid

[0126] Chlorogenic acid

[0127] Methyl cinnamate Ethyl cinnamate

[0128] Allyl cinnamate

[0129] Isobutyl cinnamate

[0130] Pentyl cinnamate

[0131] Heptyl cinnamate

[0132] Citronellyl cinnamate

[0133] Ethyl 3-phenylbut-2-enoate

[0134] 3-Amino-3-phenyl-acrylic acid ethyl ester

[0135] Ethyl 3-(pyridin-2-yl)acrylate ethyl (2)-3-(furan-2-yl)prop-2-enoate

[0136] Ethyl 2-Cyano-3-(2-furanyl)acrylate

[0137] Cinnamyl alcohol

[0138] Gallic acid Gallic acid ethyl ester (ethyl gallate)

[0139] Syringic acid

[0140] Vanillic acid

[0141] Protocatechuic acid The UV absorbing agents described herein are solid or liquid under atmospheric pressure (101 325 Pa) and room temperature (25°C). To obtain a homogenous composition or stable emulsion, at least one UV absorbing agent should be liquid.

[0142] In certain embodiments, the UV absorbing agent comprises at least one a liquid UV absorbing agent.

[0143] In certain embodiments, the UV absorbing agent comprises at least one a liquid UV absorbing agent, wherein the liquid UV absorbing agent is selected from a compound of formula I, or a salt thereof, particularly a compound of formula I,

[0144] Ar-Xn-R (I), wherein

[0145] Ar is an unsubstituted 5- or 6-membered aryl or heteroaryl,

[0146] X is a substituted or unsubstituted C2-4-alkenyl, particularly C2-3-alkenyl, more particularly C2- alkenyl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R7, and -N(R8)-R9, with R7, R8and R9being independently selected from H and Ci-6-alkyl, n is 1 ,

[0147] R is selected from -C(=O)-R10, -C(=O)-O-R12, -O-C(=O)-R13, -C(=O)-N(R14)-R15, -N(R16)- C(=O)-R17, particularly -C(=O)-R10, -C(=O)-O-R12, with R10being H,

[0148] R12, R13being selected from C2-s-alkyl, C2-s-alkenyl, C2-s-alkinyl,

[0149] R14, R15, R16and R17being independently selected from H, Ci-s-alkyl, C2-s-alkenyl, C2- 8-alkinyl, Cs-e-cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, particularly from H, Ci-8-alkyl, C2-s-alkenyl, C2-8-alkinyl, more particularly from H, Ci-4-alkyl, C2-4-alkenyl, C2-4-alkinyl.

[0150] In certain embodiments, Ar is selected from an unsubstituted furyl, thienyl, pyrrolyl, phenyl, pyridyl and pyrimidinyl, particularly furyl, pyrrolyl, phenyl, pyridyl and pyrimidinyl, more particularly furyl, phenyl, pyridyl and pyrimidinyl.

[0151] In certain embodiments, Ar is selected from an unsubstituted furyl, phenyl, pyridyl.

[0152] In certain embodiments, Ar is an unsubstituted phenyl.

[0153] In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly C2-3- alkenyl, more particularly C2-alkenyl, wherein one or more substituents are selected from Ci- 6-alkyl, and -N(R8)-R9, particularly Ci-3-alkyl and -N(R8)-R9, more particularly methyl, and - N(R8)-R9. In certain embodiments, X is defined as above and R7, R8and R9being independently selected from H and Ci-3-alkyl, particularly H and methyl.

[0154] In certain embodiments, R8and R9are H.

[0155] In certain embodiments, X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2- alkenyl, wherein one or more substituents are selected from methyl and -NH2.

[0156] In certain embodiments, X is unsubstituted.

[0157] In certain embodiments, R is selected from -C(=O)-R10, -C(=O)-O-R12, -O-C(=O)-R13, particularly -C(=O)-R10, -C(=O)-O-R12, with R10being H, and R12, R13being selected from C2- s-alkyl, C2-8-alkenyl.

[0158] In certain embodiments, R is selected from -C(=O)-R10, -C(=O)-O-R12, -O-C(=O)-R13, particularly -C(=O)-R10, -C(=O)-O-R12, with R10being H, and R12, R13being selected from C2- 6-alkyl, C2-6-alkenyl.

[0159] In certain embodiments, the UV absorbing agent comprises at least one liquid UV absorbing agent, wherein the UV absorbing agent is selected from cinnamaldehyde, ethyl cinnamate, allyl cinnamate, isobutyl cinnamate, pentyl cinnamate, heptyl cinnamate, ethyl 3-phenylbut-2- enoate, 3-amino-3-phenyl-acrylic acid ethyl ester, ethyl 3-(pyridin-2-yl)acrylate, ethyl (2)-3- (furan-2-yl)prop-2-enoate.

[0160] In certain embodiments, the UV absorbing agent comprises at least one liquid UV absorbing agent, wherein the UV absorbing agent is selected from ethyl cinnamate, allyl cinnamate, isobutyl cinnamate, pentyl cinnamate, heptyl cinnamateethyl 3-phenylbut-2-enoate, 3-amino- 3-phenyl-acrylic acid ethyl ester, ethyl 3-(pyridin-2-yl)acrylate, ethyl (2E)-3-(furan-2-yl)prop-2- enoate.

[0161] In certain embodiments, the UV absorbing agent comprises at least one liquid UV absorbing agent, wherein the UV absorbing agent is selected from cinnamaldehyde, ethyl cinnamate, allyl cinnamate, isobutyl cinnamate, pentyl cinnamate, heptyl cinnamate, ethyl 3-phenylbut-2- enoate, 3-amino-3-phenyl-acrylic acid ethyl ester.

[0162] In certain embodiments, the UV absorbing agent is selected from allyl cinnamate, ethyl cinnamate, cinnamaldehyde, isobutyl cinnamate, particularly ethyl cinnamate.

[0163] In certain embodiments, the UV absorbing agent is a liquid UV absorbing agent.

[0164] In addition to a liquid UV absorbing agent as described above, the composition may comprise further UV absorbing agents that are solid at atmospheric pressure and room temperature. The latter increase of the composition and are therefore referred to as UV- absorbing enhancing agents. In the context of the present invention, the term “UV-absorbing enhancing agent” shall refer to compounds exhibiting absorbance in the wavelength range between 230 - 400 nm.

[0165] According to an embodiment of the invention, the UV absorbing agent comprises at least one liquid UV absorbing agent and at least one solid UV absorbing agent.

[0166] In certain embodiments, the UV absorbing agent comprises at least one liquid UV absorbing agent and at least one UV absorbing enhancing agent.

[0167] According to an embodiment of the invention, the composition comprises at least one UV absorbing enhancing agent, which is a compound of formula I, characterized in that

[0168] - Ar is an unsubstituted phenyl,

[0169] X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2-alkenyl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R7, -N(R8)-R9and -CN, with R7, R8and R9being independently selected from H and Ci-6-alkyl,

[0170] R is selected from -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, -C(=O)-N(R14)-R15, -N(R16)- C(=O)-R17, particularly -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, with R11being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl, C3-6- cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, particularly R11is H or Ci-6-alkyl, more particularly R11is H,

[0171] R12, R13being selected from H and -CH3, a C9-24-alkyl, a C9-24-alkenyl, a Cg-24-alkinyl, particularly H and -CH3, a Cg-16-alkyl, a Cg-16-alkenyl,

[0172] R14, R15, R16and R17being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24- alkinyl, particularly H or Ci-6-alkyl, more particularly H, n is 1 , and / or

[0173] - Ar is an unsubstituted 5- or 6-membered aryl or heteroaryl,

[0174] X is a C2-4-alkenyl, particularly a C2-alkenyl, substituted by one or more substituents -CN,

[0175] R is selected from -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, -C(=O)-N(R14)-R15, -N(R16)- C(=O)-R17, particularly -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, with R11being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl, C3-6- cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, particularly R11is H or Ci-6-alkyl, more particularly R11is H,

[0176] R12, R13being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl, C3-6- cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, particularly R12and R13are independently selected from H and a Ci-16-alkyl, a C2-i6-alkenyl, more particularly H and a Ci-6-alkyl, more particularly H and Ci-3-alkyl,

[0177] R14, R15, R16and R17being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24- alkinyl, particularly H or Ci-6-alkyl, more particularly H, n is 1 , and / or

[0178] - Ar is a substituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R4, -N(R5)-R6and -CN, with R4, R5and R6being independently selected from H and Ci-6-alkyl,

[0179] X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2-alkenyl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R7, -N(R8)-R9and -CN, with R7, R8and R9being independently selected from H and Ci-6-alkyl,

[0180] R is selected from -C(=O)-R10, -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, -C(=O)-N(R14)-R15, - N(R16)-C(=O)-R17, with R10, R11, R12, R13, R14, R15, R16and R17being independently selected from H, C1-24- alkyl, C2-24-alkenyl, C2-24-alkinyl, C3-6-cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, n is 0 or 1 , particularly 1.

[0181] Particularly if Ar is a substituted aryl or heteroaryl, reference is made to the embodiments described above, particularly with regard to the definitions of Ar, X and R and their respective substituents.

[0182] According to an embodiment of the invention, the at least one UV absorbing enhancing agent is selected from the group consisting of gallic acid, sinapic acid, coumaric acid, gallic acid ethyl ester, ferulic acid, cinnamic acid, caffeic acid, syringic acid, vanillic acid, protocatechuic acid, chlorogenic acid, cinnamyl alcohol, methyl cinnamate, citronellyl cinnamate, ethyl 2- cyano-3-(2-furanyl)acrylate.

[0183] According to an embodiment of the invention, the at least one UV absorbing enhancing agent is selected from the group consisting of gallic acid, sinapic acid, coumaric acid, gallic acid ethyl ester, ferulic acid, cinnamic acid, caffeic acid, syringic acid, vanillic acid, protocatechuic acid, chlorogenic acid, cinnamyl alcohol, methyl cinnamate, ammonium sinapate.

[0184] According to an embodiment of the invention, the at least one UV absorbing enhancing agent is selected from the group consisting of gallic acid, sinapic acid, coumaric acid, gallic acid ethyl ester, ferulic acid, cinnamic acid, caffeic acid, syringic acid, vanillic acid, protocatechuic acid, chlorogenic acid, cinnamyl alcohol, methyl cinnamate. According to an embodiment of the invention, the resin comprises a biobased or a fossilbased resin, in particular a biobased resin.

[0185] According to an embodiment of the invention, the resin is a biobased or a fossil-based resin, in particular a biobased resin.

[0186] According to an embodiment of the invention, the biobased resin is selected from the group consisting of shellac, cellulose acetate, nitrocellulose, tara gum, pine rosin, particularly shellac.

[0187] According to an embodiment of the invention, the fossil-based resin is selected from the group consisting of polyurethane, epoxy resin, acrylate resin, alkyd resin.

[0188] In certain embodiments, the proportion of the resin in relation to the total weight of the composition is at least 10%, particularly at least 15%.

[0189] According to an embodiment of the invention, the composition comprises a solvent, wherein the solvent is alcohol-based or water-based.

[0190] In certain embodiments of the invention, the composition comprises a solvent, wherein the solvent is ethanol.

[0191] In certain embodiments of the invention, the composition comprises a solvent, wherein the solvent is water.

[0192] In certain embodiments of the invention, the composition comprises a solvent, wherein the solvent is water, and further comprises a carbonate salt, preferably NH4CO3.

[0193] In certain embodiments, the proportion of the solvent in relation to the total weight of the composition is at least 20%, particularly at least 25%, more particularly at least 30%, even more particularly at least 35%.

[0194] In certain embodiments, the composition comprises at least one additive, wherein the additive is selected from the group consisting of a hydrophobic liquid, particularly linseed oil, tung oil, vegetable oil, epoxidized vegetable oil, and / or hydrophobic solid, particularly beeswax or carnauba wax and / or wood penetration facilitator, particularly dimethylsulfoxide, 1-ethyl-3- methylimidazolium acetate, dimethyl acetamide, a surfactant, particularly dimethylsulfoxide, 1-ethyl-3-methylimidazolium acetate, dimethyl acetamide.

[0195] In the context of the present invention, the term “wood penetration facilitator” shall refer to substances that are able to penetrate into wood fibers, thereby carrying further substances into wood fibers. In certain embodiments, the surfactant is selected from sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and alkylbenzene sulfonates.

[0196] In certain embodiments, the proportion of the additive in relation to the total weight of the composition is at least 0.1 %, particularly at least 0.5%, more particularly at least 1 %.

[0197] According to an embodiment of the invention, the proportion of the UV absorbing agent is at least 15% (w / w), particularly at least 25% (w / w), more particularly at least 35% (w / w) in relation to the total weight of the composition.

[0198] According to an embodiment of the invention, a weight ratio (w / w) between the UV absorbing agent and the resin in the composition is between 0.5 and 3, particularly between 1 and 2.

[0199] In certain embodiments, the weight ratio (w / w) between the UV absorbing agent and the resin in the composition is 2.

[0200] According to an embodiment of the invention, a weight ratio (w / w) between the UV absorbing agent and the solvent is between 0.5 and 1 .

[0201] In certain embodiments, the weight ratio (w / w) between the UV absorbing agent and the solvent is 1.

[0202] In certain embodiments, the composition comprises at least one UV absorbing enhancing agent, wherein the proportion of the UV absorbing enhancing agent in relation to the total weight of the composition is between 0 and 2%, particularly between 0% and 1.5%, more particularly said proportion is 1%.

[0203] In certain embodiments, the composition comprises at least one UV absorbing enhancing agent, wherein the proportion of the UV absorbing enhancing agent in relation to the total weight of the composition is between 0.1 and 2%, particularly between 0.1 and 1.5%, more particularly said proportion is 1%.

[0204] In certain embodiments, the proportion of the resin, particularly shellac, in relation to the total weight of the composition is between 10% and 40%, particularly between 15% and 40%, more particularly between 19% and 33% (w / w).

[0205] In certain embodiments, the proportion of the solvent, particularly ethanol and / or water, in relation to the total weight of the composition is between 20% and 80%, particularly between 25% and 70%, more particularly between 30% and 70%, even more particularly between 35% and 61 % (w / w).

[0206] In certain embodiments, the proportion of the solvent, particularly ethanol and / or water, in relation to the total weight of the composition is between 30% and 65%. In certain embodiments, the proportion of the solvent, particularly ethanol, in relation to the total weight of the composition is between 30% and 65%.

[0207] In certain embodiments, the proportion of the UV absorbing agent, particularly ethyl cinnamate, in relation to the total weight of the composition is between 10% and 50%, particularly between 10% and 40%, more particularly between 10% and 36%.

[0208] In certain embodiments, the proportion of the additive, particularly linseed oil, in relation to the total weight of the composition is between 0.1% and 15%, particularly 0.5% and 15%, more particularly between 1% and 10%, even more particularly between 1 % and 9 %.

[0209] In certain embodiments, the proportion of the UV absorbing enhancing agent, particularly sinapic acid, in relation to the total weight of the composition is between 0% and 2%, particularly between 0% and 1.5%, more particularly 1%.

[0210] In certain embodiments, the proportion of the UV absorbing enhancing agent, particularly sinapic acid, in relation to the total weight of the composition is between 0.1 % and 2%, particularly between 0.1% and 1.5%, particularly 1 %.

[0211] According to an embodiment of the invention, the composition comprises:

[0212] - between 19 % and 33 % (w / w) of resin, particularly shellac,

[0213] - between 35 % and 61 % (w / w) of solvent, particularly ethanol and / or water,

[0214] - between 15 % and 50 %, particularly between 10 % and 40 %, more particularly between 15 % and 36 %, (w / w) of UV absorbing agent, particularly ethyl cinnamate,

[0215] - between 1 % and 9 % (w / w) of additive, particularly by the linseed oil, and

[0216] - between 0 and 2 wt.% UV absorbing enhancing agent, wherein the sum of proportions does not exceed 100%.

[0217] According to an embodiment of the invention, the composition comprises:

[0218] - between 19 % and 33 % (w / w) of resin, particularly shellac,

[0219] - between 35 % and 61 % (w / w) of solvent, particularly ethanol,

[0220] - between 10 % and 50 %, particularly between 10 % and 40 %, more particularly between 10 % and 36 %, (w / w) of UV absorbing agent, particularly ethyl cinnamate,

[0221] - between 1 % and 9 % (w / w) of additive, particularly by the linseed oil, and

[0222] - between 0 and 2 wt.% UV absorbing enhancing agent, wherein the sum of proportions does not exceed 100%.

[0223] According to an embodiment of the invention, the composition comprises: - between 19 % and 33 % (w / w) of resin, particularly shellac,

[0224] - between 35 % and 61 % (w / w) of solvent, particularly ethanol and / or water,

[0225] - between 15 % and 50 %, particularly between 10 % and 40 %, more particularly between 15 % and 36 %, (w / w) of UV absorbing agent, particularly ethyl cinnamate,

[0226] - between 1 % and 9 % (w / w) of additive, particularly by the linseed oil, and

[0227] - between 0.1 and 2 wt.% UV absorbing enhancing agent, wherein the sum of proportions does not exceed 100%.

[0228] According to an embodiment of the invention, the composition comprises:

[0229] - between 19 % and 33 % (w / w) of resin, particularly shellac,

[0230] - between 35 % and 61 % (w / w) of solvent, particularly ethanol,

[0231] - between 10 % and 50 %, particularly between 10 % and 40 %, more particularly between 10 % and 36 %, (w / w) of UV absorbing agent, particularly ethyl cinnamate,

[0232] - between 1 % and 9 % (w / w) of additive, particularly by the linseed oil, and

[0233] - between 0.1 and 2 wt.% UV absorbing enhancing agent, wherein the sum of proportions does not exceed 100%.

[0234] According to an embodiment of the invention, the composition comprises:

[0235] - between 19 % and 33 % (w / w) of resin, particularly shellac,

[0236] - between 35 % and 61 % (w / w) of solvent, particularly ethanol and / or water,

[0237] - between 15 % and 50 %, particularly between 10 % and 40 %, more particularly between 15 % and 36 %, (w / w) of UV absorbing agent, particularly ethyl cinnamate, and

[0238] - between 1 % and 9 % (w / w) of additive, particularly by the linseed oil, wherein the sum of proportions does not exceed 100%.

[0239] According to an embodiment of the invention, the composition comprises:

[0240] - between 19 % and 33 % (w / w) of resin, particularly shellac,

[0241] - between 35 % and 61 % (w / w) of solvent, particularly ethanol, between 10 % and 50 %, particularly between 10 % and 40 %, more particularly between 10 % and 36 %, (w / w) of UV absorbing agent, particularly ethyl cinnamate, and between 1 % and 9 % (w / w) of additive, particularly by the linseed oil, wherein the sum of proportions does not exceed 100%.

[0242] A second aspect of the invention relates to a substrate, wherein at least one surface of the substrate comprises at least in a section a coating, wherein the coating is derived from the composition according to the first aspect of the invention.

[0243] In certain embodiments, the substrate comprises at least in a section a coating, wherein the coating is obtained by applying the composition according to the first aspect of the invention.

[0244] In certain embodiments, the composition according to the first aspect of the invention is hardened.

[0245] In certain embodiments, the coating comprises a resin, particularly shellac, and a UV absorbing agent, particularly ethyl cinnamate, according to the first aspect of the invention.

[0246] In certain embodiments, the resin according to the first aspect of the invention is hardened.

[0247] In certain embodiments, a weight ratio (w / w) between the UV absorbing agent and the resin in the coating is between 0.5 to 3, particularly 1 and 2, more particularly said weight ratio is 2.

[0248] In certain embodiments, the coating comprises a resin, particularly shellac, and a UV absorbing agent, particularly ethyl cinnamate, and an additive, particularly a hydrophobic additive, according to the first aspect of the invention.

[0249] In certain embodiments, the substrate is selected from wood, plastic, fabric and wood-based material.

[0250] In certain embodiments, the substrate is selected from wood and wood-based material.

[0251] In certain embodiments, the substrate is selected from wood.

[0252] In certain embodiments, the wood-based material is selected from a wood-plastic composite, laminate, glulam and fiberboard.

[0253] Reference is made to the description and embodiments of the first aspect of the invention.

[0254] A third aspect of the invention relates to a method for protecting a surface of a substrate from UV electromagnetic radiation, comprising the steps: providing the surface of the substrate, and coating the surface with a composition according to the first aspect of the invention.

[0255] Reference is made to the description and embodiments of the first and second aspect of the invention. Wherever alternatives for single separable features are laid out herein as “embodiments”, it is to be understood that such alternatives may be combined freely to form discrete embodiments of the invention disclosed herein.

[0256] The invention is further illustrated by the following examples and figures, from which further embodiments and advantages can be drawn. These examples are meant to illustrate the invention but not to limit its scope.

[0257] Description of the Figures

[0258] Fig. 1 shows images of the shellac-ethyl cinnamate-linseed oil mixture. Left: mixture prepared with a clear shellac; right: mixture prepared with a ruby-colored shellac. Both mixtures are homogenous and do not show phase separation even after a long time of storage. The mixtures have the composition: Shellac: 19 wt.%, Ethanol: 36 wt.%, Ethyl cinnamate: 36 wt.%, Linseed oil: 9 wt.%..

[0259] Fig. 2 Demonstration from 2 weeks of accelerated weathered our coating compared to commercially available products (Products 1-3) that include UV-blockers. All wood samples had two layers of coat, each of 2mL applied with a brush. The wood substrate is spruce. Our coating was derived from a solution of composition: Shellac: 19 wt.%, Ethanol: 36 wt.%, Ethyl cinnamate: 36 wt.%, Linseed oil: 9 wt.%. Product 1 : alkyd base, UV-blocker: 2.5 wt.% Benzotriazole. Product 2: Oil-based, UV-blocker: 1-5 wt.% Benzotriazole. Product 3: alkyd-based, UV-blocker: TiO2. The coating according to the invention shows equal or better UV-protection compared to commercial products with UV-blocking technology.

[0260] Fig. 3 Total color change (AE) from accelerated weathering of wood treated with a coating according to the invention compared to wood treated with commercially available wood UV protective coatings. Our coating was derived from a solution of composition: Shellac: 19 wt.%, Ethanol: 36 wt.%, Ethyl cinnamate: 36 wt.%, Linseed oil: 9 wt.%. Product 1 : alkyd base, UV-blocker: 2.5 wt.% Benzotriazole. Product 2: Oil-based, UV-blocker: 1-5 wt.% Benzotriazole. Product 3: alkyd-based, UV-blocker: TiO2.

[0261] Fig. 4 Transmittance spectra of a shellac coating, commercially available coatings that include UV-blocking technologies (Product 1 , Product 2 and Product 3), and a coating according to the invention. Our coating was derived from a solution of composition: Shellac: 19 wt.%, Ethanol: 36 wt.%, Ethyl cinnamate: 36 wt.%, Linseed oil: 9 wt.%. Product 1 : alkyd base, UV-blocker: 2.5 wt.% Benzotriazole. Product 2: Oil-based, UV-blocker: 1-5 wt.% Benzotriazole. Product 3: alkyd-based, UV-blocker: TiO2.

[0262] Fig. 5 Total color change of wooden substrates coated with commercial coatings including UV-blocking technologies (Product 1, Product 2 and Product 3) and a coating according to the invention (before UV irradiation or weathering) compared to native wood (NW). Our coating was derived from a solution of composition: Shellac: 19 wt.%, Ethanol: 36 wt.%, Ethyl cinnamate: 36 wt.%, Linseed oil: 9 wt.%. Product 1: alkyd base, UV-blocker: 2.5 wt.% Benzotriazole. Product 2: Oil-based, UV-blocker: 1-5 wt.% Benzotriazole. Product 3: alkyd-based, UV-blocker: TiO2. L* indicates lightness, a* is the red / green coordinate, and b* is the yellow / blue coordinate.

[0263] Fig. 6 Transmission spectra of different compositions consisting of ethanol and ethylcinnamate, for different weight ratios (w / w) of ethyl cinnamate, which demonstrate the light absorption due to ethyl cinnamate in the UV range. Pure EC: 100 wt.% ethyl cinnamate, 40%: 40 wt.% ethyl cinnamate, 30%: 30 wt.% ethyl cinnamate, 20%: 20 wt.% ethyl cinnamate and 10%: 10 wt.% ethyl cinnamate.

[0264] Fig. 7 Transmission spectra of Fig. 6, compared to a coating derived from a composition according to the invention, wherein the composition comprises 19 % (w / w) shellac, 36 % (w / w) ethanol, 36 % (w / w) ethyl cinnamate and 9 % (w / w) linseed oil. EC-Lin-S: our coating, Pure EC: 100 wt.% ethyl cinnamate, 40%: 40 wt.% ethyl cinnamate, 30%: 30 wt.% ethyl cinnamate, 20%: 20 wt.% ethyl cinnamate and 10%: 10 wt.% ethyl cinnamate.

[0265] Fig. 8 shows images of different compositions according to the invention, for weight ratios of 20%, 40 % and 60 % (w / w) of ethyl cinnamate; wherein the composition comprising 20 % (w / w) of ethyl cinnamate further comprised 64 % (w / w) of shellac and 16 % (w / w) of linseed oil; wherein the composition comprising 40 % (w / w) of ethyl cinnamate further comprised 48 % (w / w) of shellac and 12 % (w / w) of linseed oil and wherein the composition comprising 60 % (w / w) of ethyl cinnamate further comprised 32 % (w / w) of shellac and 8 % (w / w) of linseed oil.

[0266] Fig. 9 shows the accelerated aging of spruce wood coated with a water-based composition according to the invention compared to uncoated spruce wood by means of the wood’s color difference (AE). Weathering was performed in accordance with standard EN 927-6. Fig. 10 shows the UV-Vis transmission of shellac (Sh), and wood coating compositions according to the invention using linseed oil (L), ethyl cinnamate (EC), and sinapic acid (S).

[0267] Fig. 11 shows the visual transmission of shellac and wood coating compositions according to the invention under natural lightning (daylight), a 255 nm UV light (UVB), and a 366 nm UV light (UVA). PS: shellac, ethyl cinnamate, and linseed oil, and PSE: shellac, ethyl cinnamate, linseed oil, and sinapic acid.

[0268] Fig. 12 shows the visual colour change of coated spruce wood with composition according to the innovations water-based wood coating from 2 weeks of accelerated weathering compared to native spruce wood, according to weathering standard EN 927-6.

[0269] Fig. 13 shows the change in Aa* during accelerated aging of spruce wood coated with a water-based composition according to the invention compared with uncoated spruce wood. Weathering was performed in accordance with standard EN 927-6.

[0270] Fig. 14 shows the change in Ab* during accelerated aging of spruce wood coated with a water-based composition according to the invention compared with uncoated spruce wood. Weathering was performed in accordance with standard EN 927-6.

[0271] Fig. 15 shows the change in AL* during accelerated aging of spruce wood coated with a water-based composition according to the invention compared with uncoated spruce wood. Weathering was performed in accordance with standard EN 927-6.

[0272] Spruce wood with a length of 15 cm and width of 7.5 cm was used as substrates for the inventive coating. The artificial weathering test was performed in a QUV Accelerated Weathering Tester (Q-LAB, Miami, USA) equipped with UVA-340 lamps. A measurement period of 2 weeks was used, wherein an exposure cycle of 1 week consists of condensation followed by a sub-cycle of water spraying and UV irradiation following the European standard EN 927-6.

[0273] Colour evaluation of the wood prior and after accelerated weathering were determined in the CIE L*a*b* system using a Chroma Meter CR-200 (Minolta, Miami, Japan). L* represents lightness ranging from black (0) to white (100). a* and b* are the chromaticity indices, in which +a* is the red, -a* is the green, +b* is the yellow and -b* is the blue direction. The total colour change is defined according to the following equation AE = AL2+ Aa2+ Ab2.

[0274] Transmission of the liquid mixtures and coatings were evaluated on a UV-vis spectrophotometer (LAMBDA 850, PerkinElmer, Waltham, USA).

[0275] Example 2:

[0276] Shellac flakes were gradually dissolved in an aqueous solution containing 0.2 M NH4HCO3 at 50 °C until a concentration of 20wt% shellac were achieved. The emulsion was formed by mixing the aqueous shellac solution with oil, preferably linseed oil or tung oil, and the addition of a plasticizing agent, preferably ethyl cinnamate, under stirring or sonication. An additional water-based UV blocker could be added for further protection, more specifically ammonium sinapate. The final formulation was a white aqueous-based emulsion that could be brushed or sprayed onto the substrate to form transparent UV-protecting coatings.

Claims

Claims1. A composition for absorbing ultraviolet (UV) electromagnetic radiation, wherein the composition comprises at least one UV absorbing agent and a film-forming agent, characterized in that: the UV absorbing agent is a compound of formula I, or a salt thereof,Ar-Xn-R (I), whereinAr is a substituted or unsubstituted 5- or 6-membered aryl or heteroaryl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R4, - N(R5)-R6and -CN, with R4, R5and R6being independently selected from H and Ci- 6-alkyl,X is a substituted or unsubstituted C2-4-alkenyl, particularly a C2-alkenyl, wherein one or more substituents are selected from Ci-6-alkyl, -O-R7, - N(R8)-R9and -CN, with R7, R8and R9being independently selected from H and Ci- 6-alkyl,R is selected from -C(=O)-R10, -O-R11, -C(=O)-O-R12, -O-C(=O)-R13, - C(=O)-N(R14)-R15, -N(R16)-C(=O)-R17, with R10, R11, R12, R13, R14, R15, R16and R17being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl, C3-6- cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, n is 0 or 1 , particularly 1 , the film forming agent comprises, particularly consists of, a resin, the proportion of the UV absorbing agent is at least 10% in relation to the total weight of the composition, and wherein the UV absorbing agent is selected in such a way that it is compatible with the resin, particularly the UV absorbing agent is selected in such a way that the composition is homogenous, or the UV absorbing agent is selected in such a way that the composition forms a stable emulsion.

2. The composition according to claim 1 , wherein Ar is selected from a substituted or unsubstituted furyl, thienyl, pyrrolyl, phenyl, pyridyl, and pyrimidinyl.

3. The composition according to any of the preceding claims, wherein R is selected from -C(=O)-R10, -O-R11, -C(=O)-O-R12, -C(=O)-N(R14)-R15, particularly -C(=O)-R10, -O-R11, -C(=O)-O-R12, more particularly -O-R11, -C(=O)-O-R12, even more particularly -C(=O)- O-R12, with R10, R11, R12, R14and R15being defined as described above.

4. The composition according to any of the preceding claims, wherein R10, R11, R12, R14and R15being independently selected from H, Ci-24-alkyl, C2-24-alkenyl, C2-24-alkinyl, Cs-e-cycloalkyl, wherein the C3-6-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH, particularly from H, Ci-16-alkyl, C2-i6-alkenyl, C2-16 alkinyl, more particularly from H, Ci-s-alkyl, C2-8-alkenyl, 02-s-alkinyl , even more particularly from H, Ci-4-alkyl, C2-4-alkenyl, C2-4-alkinyl.

5. The composition according to any of the preceding claims, wherein the UV absorbing agent is a compound of formula II, III or IV, particularly II or III, more particularly II, or a salt thereof,(IV), whereinR1is selected from H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkinyl, -O-R3,R2is selected from -O-R4, CN or Ci-Ce alkyl, -N(R5)-R6,R18is selected from -O-R3, -Ci-6-alkyl-O-R3,R19is selected from -O-R4, CN or Ci-Ce alkyl, -N(R5)-R6,R20is selected from H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkinyl, -O-R3,R21is selected from is selected from -O-R4, CN or Ci-Ce alkyl, -N(R5)- R6, with m, p or p being 0, 1 , 2, 3, 4 or 5. particularly 0, 1 , 2 or 3, whereinR3is selected from H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkinyl, Cs-e-cycloalkyl, wherein the Cs-e-cycloalkyl may optionally be substituted by one or more substituents -OH or -COOH,R4is selected from H, C1-C3 alkyl,R5and R6are independently selected from H and Ci-6-alkyl.

6. The composition according to any of the previous claims, wherein the UV absorbing agent comprises at least one a liquid UV absorbing agent, particularly a liquid UV absorbing agent selected from the group consisting of allyl cinnamate, ethyl cinnamate, cinnamaldehyde, isobutyl cinnamate, particularly ethyl cinnamate, pentyl cinnamate, heptyl cinnamate, ethyl 3-phenylbut-2-enoate, 3-amino-3-phenyl-acrylic acid ethyl ester, ethyl 3-(pyridin-2-yl)acrylate, ethyl (2E)-3-(furan-2-yl)prop-2-enoate, particularly allyl cinnamate, ethyl cinnamate, cinnamaldehyde, isobutyl cinnamate, more particularly ethyl cinnamate .

7. The composition according to any of the previous claims, wherein the composition comprises at least one liquid UV absorbing agent and at least one UV absorbing enhancing agent, particularly at least one UV absorbing enhancing agent selected from the group consisting of gallic acid, sinapic acid, coumaric acid, gallic acid ethyl ester, ferulic acid, cinnamic acid, caffeic acid, syringic acid, vanillic acid, protocatechuic acid, chlorogenic acid, cinnamyl alcohol, methyl cinnamate, citronellyl cinnamate and ethyl 2-cyano-3-(2-furanyl)acrylate.

8. The composition according to one of the preceding claims, wherein the resin comprises a biobased resin, particularly selected from the group consisting of shellac, cellulose acetate, nitrocellulose, tara gum, pine rosin, ora fossil-based resin, particularly selected from the group consisting of: polyurethane, epoxy resin, acrylate resin, alkyd resin.

9. The composition according to one of the preceding claims, wherein the composition comprises a solvent, wherein the solvent is alcohol-based or water-based.

10. The composition according to claims 1-8, wherein the composition comprises a solvent, wherein the solvent is ethanol.

11. The composition according to claim 1-8, wherein the composition comprises a solvent, wherein the solvent is water.

12. The composition according to claim 11, wherein the composition further comprises a carbonate salt, preferable NH4CO3.

13. The composition according to one of the preceding claims, comprising at least one additive, wherein the additive is selected from the group consisting of a hydrophobic liquid, particularly linseed oil, tung oil, vegetable oil, epoxidized vegetable oil, and / or hydrophobic solid, particularly beeswax or carnauba wax and / or wood penetration facilitator, particularly dimethylsulfoxide, 1-ethyl-3- methylimidazolium acetate, dimethyl acetamide, a surfactant.

14. The composition according to one of the preceding claims, wherein a weight ratio (w / w) between the UV absorbing agent and the resin in the composition is between 1 and 2, particularly said weight ratio is 2, and / or a weight ratio (w / w) between the UV absorbing agent and the solvent is between 0.5 and 1 , particularly said weight ratio is 1.

15. The composition according to any of the previous claims, wherein the composition comprises at least one UV absorbing enhancing agent, wherein the proportion of the UV absorbing enhancing agent in relation to the total weight of the composition is between 0 and 2%, particularly said proportion is 1%.

16. A substrate, wherein at least one surface of the substrate comprises at least in a section a coating, wherein the coating is derived from the composition according to any of claims 1 to 15.

17. The substrate according to claim 16, wherein the substrate is selected from wood, plastic, fabric and wood-based material.

18. Method for protecting a surface of a substrate from UV electromagnetic radiation, comprising the steps:providing the surface of the substrate, and coating the surface with a composition according to one of the claims 1 to 15.

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