The present invention relates to the field of radiation curable coating compositions useful for coating a substrate in order to provide it with anti-viral activity. The present invention also relates to an anti-viral coating layer formed from the radiation curable coating composition and further to a substrate coated with the anti-viral coating layer. The present invention further relates to a method for preparing the radiation curable coating composition and to a method for forming an anti-viral coating layer on a substrate.

While viruses have always been a concern to human and animal health and well-being, increased concern has arisen with respect to a growing number of new viruses such as those associated with SARS. While viruses have several methods of transmission from one host/victim to another, one mode of transmission involve surfaces that act as a stopover for the viruses. Thus, one key response to any viral threat is to render susceptible surfaces antiviral by applying a coating on the surface in order to provide it with anti-viral activity. Thus, there exists a need for coatings which can deactivate viruses, and particularly enveloped viruses, upon contact. As for example described in “Viral Capsids and Envelopes: Structure and Function”, William Lucas and David M Knipe, Encyclopedia of Life Sciences, 2002, virus particles contain the viral genome packaged in a protein coat, called a capsid, and sometimes contain a lipid coat, i.e. a lipid bilayer and associated proteins, called the envelope. An enveloped virus is a virus that has an envelope. Radiation curable coating compositions have long been used to produce coatings having desired coating characteristics. For example coating compositions are used to protect surfaces from the environment, to conceal surface irregularities, to provide a surface which is more receptive to further treatment, or to enhance the surface appearance. The anti-viral coating composition should be easy to apply and show good chemical resistances, and is preferably free of toxic or harmful metals and also halogen-free.

The object of the present invention is to provide a radiation curable coating composition that is able to provide a coating with anti-viral activity without using halogens and/or toxic or harmful metals like copper, zinc or silver, and in addition the water resistance can be retained at least at sufficient level. According to the invention there is provided a radiation curable coating composition comprising:

A) a film-forming component comprising one or more monomers, oligomers and/or polymers having one or more radiation crosslinkable ethylenically unsaturated bonds,

B) one or more salts with a structure according to the following formula

R2

R4 wherein

R1 is an alkyl group or an alkenyl group having from 7 to 22 carbon atoms, R2 is a group with one or more radiation crosslinkable ethylenically unsaturated bonds,

R3 is H, an optionally substituted alkyl group or an optionally substituted alkenyl group or a group with one or more radiation crosslinkable ethylenically unsaturated bonds, R4 is an optionally substituted alkyl group or an optionally substituted alkenyl group, or R3 and R4 together with the NH+ form a protonated morpholine ring, and wherein said salts B) are present in an amount such that the coating composition comprises from 0.1 to 0.65 millimoles of NIT'OOC per g coating composition.

It has surprisingly been found that the coating composition of the invention is able to provide a coating with anti-viral activity without having to use halogens and/or toxic or harmful metals like copper, zinc or silver, while despite the presence of the salt at least good water resistance can be obtained. An additional advantage of the coating composition of the invention is that it is able to provide a coating with at least good methyl ethyl ketone and/or ethanol resistance. Furthermore, it has surprisingly been found that the coffee, mustard, red wine and/or paraffin resistance, can also be retained at least at sufficient level or is not substantially affected or even not affected at all by the presence of the salt. Even the resistances to liquids widely used in hospitals, in particular crystal violet solution, KMnO4 solution, eosin solution, cooper and/or safranin, can be retained at least at sufficient level or are even not substantially affected. An additional advantage of the radiation curable coating compositions of the invention is that the coating can be cleaned with ammonia while the coating retains anti-viral activity.

A coating having anti-viral activity (further referred to as anti-viral coating) means that the coating is capable of inactivating preferably at least 99%, more preferably at least 99.2 %, more preferably at least 99.4%, more preferably at least 99.6%, most preferably at least 99.9% of the virus present on the surface coating within 6 hours. In the present application, anti-viral activity is determined according to IS021702:2019(E), whereby the infectivity of the virus is measured after contacting for 6 hours and using PHI6 bacteriophages as virus and Pseudomonas syringae as host cells.

A coating having good water resistance is understood here to mean a coating with a water resistance, measured as described herein, after 1 hour with a rating of 4 or higher; preferably a water resistance after 16 hours with a rating of 4 or higher; more preferably a water resistance after 24 hours with a rating of 4 or higher. A coating having good 48% ethanol in water resistance, measured as described herein, is understood here to mean a coating with a 48% ethanol in water resistance after 1 hour with a rating of 3 or higher; preferably a 48% ethanol in water resistance after 6 hours with a rating of 3 or higher; more preferably a 48% ethanol in water resistance after 16 hours with a rating of 3 or higher.

A coating having good methyl ethyl ketone (MEK) resistance, measured as described herein, is understood here to mean a coating with a rating of 3 or higher, preferably with a rating of 4 or higher, after having been rubbed 200 times.

The term "coating composition" encompasses, in the present description, paint, coating, varnish, including overprint varnish, and ink compositions, without this list being limiting. In this description, the expression "in the range of from ... to ... " and the expression “from ... to ... “ is understood as including the limits cited and also all the intermediate values.

For all upper and/or lower boundaries of any range given herein, the boundary value is included in the range given, unless specifically indicated otherwise. Thus, when saying from x to y, means including x and y and also all intermediate values. The present invention provides a coating composition curable by radiation, such as UV radiation including IIV-A, IIV-B and IIV-C radiations; electron beam radiation; infrared radiations; or lights in visible or invisible wavelengths. The composition comprises components which carry ethylenically unsaturated bond functionality, preferably acrylic and/or methacrylic double bonds, capable of crosslinking which is susceptible to initiation by radiation optionally in combination with photoinitiator. In one example, the sun light can be suitable for curing the liquid coating layer. In another example, an electron-beam generator can be suitable for curing the liquid coating layer. In another and preferred example, UV lamps are used for curing the liquid coating layer. Thus, UV radiation is preferably applied. Optionally a photo-initiator is added to the radiation curable coating composition, especially if curing is by UV-radiation. Preferably, the radiation curable composition of the invention comprises a photo-initiator and UV-radiation is applied to obtain a cured coating. Thus the composition is preferably UV radiation curable. More preferably, the composition is 100% radiation curable (substantially free of water and volatile solvent)). Most preferably the composition is 100% UV radiation curable. A 100% radiation curable composition refers to a composition which is substantially free of water and volatile solvent which preferably have to be removed before complete curing is achieved. As used herein, substantially free of water and volatile solvent (also referred to as in the substantial absence of water and volatile solvent) means that the composition contains less than 20 wt.% of water and volatile solvent, preferably less than 10 wt.% of water and volatile solvent, more preferably less than 5 wt.% of water and volatile solvent, more preferably less than 3 wt.% of water and volatile solvent, more preferably less than 1 wt.% of water and volatile solvent by weight of the radiation curable coating composition of the present invention. Volatile solvents are solvents in particular having an initial boiling point less than or equal to 250° C measured at a standard atmospheric pressure of 101.3 kPa. The start temperature of the process to radically cure the liquid coating layer can be at ambient temperatures, such as in a range of from 15 °C to 35 °C, or at elevated temperatures such as in a range from 35 °C to 150 °C. Preferably, the start temperature is in a range of from 15 °C to 35 °C.

The radiation curable coating composition of the invention comprises one or more salts B) with a structure according to the following formula R2

R4 wherein

R1 is an alkyl group or an alkenyl group having from 7 to 22 carbon atoms,

R2 is a group with one or more radiation crosslinkable ethylenically unsaturated bonds, R3 is H, an optionally substituted alkyl group or an optionally substituted alkenyl group or a group with one or more radiation crosslinkable ethylenically unsaturated bonds, said group with one or more radiation crosslinkable ethylenically unsaturated bonds not being an optionally substituted alkenyl group, R4 is an optionally substituted alkyl group or an optionally substituted alkenyl group, or R3 and R4 together with the NH+ form a protonated morpholine ring.

The radiation crosslinkable ethylenically unsaturated bonds are preferably present in (meth)acryloyl groups. The term “(meth)acryloyl” means methacryloyl or acryloyl. A (meth)acryloyl group has a radiation crosslinkable ethylenically unsaturated bond. The (meth) acryloyl groups are preferably (meth)acryloyl ester groups, (meth)acrylamide groups and any combination thereof. More preferably, the (meth)acryloyl groups are (meth)acryloyl ester groups. Even more preferably, the (meth)acryloyl groups are acryloyl ester groups.

Said salt B) comprises at least one radiation crosslinkable ethylenically unsaturated bond. Said salt B) preferably comprises at least one (meth)acryloyl group. Preferably said salt B) comprises from 1 to 6 (meth)acryloyl groups, more preferably said salt B) comprises from 1 to 4 (meth)acryloyl groups.

R1 is a linear or branched alkyl or linear or branched alkenyl group having from 7 to 22 carbon atoms. Preferably, R1 is a linear or branched alkyl or linear or branched alkenyl group having from 9 to 22 carbon atoms. Preferably R1 is a linear alkyl or linear alkenyl group having from 9 to 22 carbon atoms. R1 preferably has from 10 to 18 carbon atoms, more preferably from 10 to 17 carbon atoms, even more preferably from 11 to 17 atoms. In case R1 is an alkenyl group, it preferably has one or two ethylenically unsaturated bonds.

Preferably, R3 is an optionally substituted alkyl group or an optionally substituted alkenyl group or another (not an optionally substituted alkenyl group) group with one or more radiation crosslinkable ethylenically unsaturated bonds. An optionally substituted alkenyl group has at least one radiation crosslinkable ethylenically unsaturated bond. R3 may be an optionally substituted alkyl group or an optionally substituted alkenyl group and R4 is an optionally substituted alkyl group or an optionally substituted alkenyl group. The alkyl or alkenyl group is optionally substituted with a functional group having a heteroatom such as N and/or O, preferably O. A preferred substituent is a hydroxyl group.

R3 (in case R3 is an optionally substituted alkyl group or an optionally substituted alkenyl group) and R4 independently have preferably from 1 to 18 carbon atoms, more preferably from 2 to 10 carbon atoms.

R3 may be a group with one or more radiation crosslinkable ethylenically unsaturated bonds and R2 is a group with one or more radiation crosslinkable ethylenically unsaturated bonds. R2 and R3 (in case R3 is a group with one or more radiation crosslinkable ethylenically unsaturated bonds) preferably comprises (meth)acryloyl groups, more preferably acryloyl groups. The (meth)acryloyl groups are preferably (meth)acryloyl ester groups, (meth)acrylamide groups and any combination thereof. More preferably, the (meth)acryloyl groups are (meth)acryloyl ester groups. Most preferably, R2 and R3 (in case R3 is a group with one or more radiation crosslinkable ethylenically unsaturated bonds) comprises acryloyl ester groups.

In a preferred embodiment, R3 is, independently from R4, an optionally substituted alkyl group or an optionally substituted alkenyl group and R2 is

R5 I -CH2CH2-O(C=O)C=CH2 and R5 is H or methyl. R3 and R4 are preferably both methyl.

In another preferred embodiment, R2 and R3 are independently -CH2CH2-(C=O)-R6 and R6 is an optionally alkoxylated polyol residue with one or more (meth)acryloyl groups. In case R6 is an alkoxylated polyol residue with one or more (meth)acryloyl groups, R6 preferably has from 1 to 5 alkoxy groups. The alkoxy groups are preferably ethoxy or propoxy groups. Said salt is preferably the reaction product of a carboxylic acid R1-COOH in which R1 has a C7-C22 atom chain, preferably a C9-C22 atom chain, and a tertiary amine (R2R3R4N) having one or more radiation crosslinkable ethylenically unsaturated bonds, preferably having one or more (meth)acryloyl groups. Said carboxylic acid is preferably selected from the group consisting of caprylic acid, lauric acid, linoleic acid, stearic acid, palmitoleic acid, behenic acid and any mixture thereof. Said carboxylic acid is more preferably selected from the group consisting of lauric acid, linoleic acid, stearic acid, palmitoleic acid, behenic acid and any mixture thereof. More preferably, said carboxylic acid is selected from the group consisting of lauric acid, linoleic acid, palmitoleic acid and any mixture thereof. In a preferred embodiment, the carboxylic acid is liquid at room temperature, such as linoleic acid and palmitoleic acid. In a preferred embodiment, said tertiary amine is N,N-dimethylaminoethyl (meth)acrylate. In another preferred embodiment, said tertiary amine is the Michael addition reaction product of a primary or secondary amine with a multifunctional (meth)acrylate compound. Said multifunctional (meth) acrylate compound is preferably 1,6-hexanediol diacrylate HDDA, optionally alkoxylated trimethylolpropane tri(meth)acrylate TMPT(M)A, optionally alkoxylated pentaerythritol tri- and/or tetraacrylate (PETA), tripropylene glycol di(meth)acrylate (TPGD(M)A) and any mixture thereof.

Examples of preferred salts B) (n is preferably from 1 to 5) are

Said salts B) are present in the coating composition in such an amount that the coating composition comprises from 0.1 to 0.65 millimoles of NIT'OOC per g coating composition, preferably from 0.2 to 0.5 millimoles of NIT'OOC per g coating composition, more preferably from 0.25 to 0.4 millimoles of NIT'OOC per g coating composition. Preferably, said salts B) are present in the coating composition in such an amount that the coating composition comprises from 0.1 to 0.65 millimoles of 'OOC-R1 per g coating composition, more preferably from 0.2 to 0. 5 millimoles of 'OOC-R1 per g coating composition, even more preferably from 0.25 to 0.4 millimoles 'OOC-R1 per g coating composition.

The radiation curable coating composition of the invention can be obtained by adding said salts B) to a composition comprising a film-forming component A) comprising one or more monomers, one or more oligomers and/or one or more polymers having one or more radiation crosslinkable ethylenically unsaturated bonds. Preferably, said salts B) are in-situ formed in the radiation curable coating composition. This can for example be effected by adding one or more carboxylic acids R1-COOH and one or more tertiary amines R2R3R4N to a composition already comprising one or more of the film-forming components and stirring the so-obtained mixture to obtain a clear solution.

The radiation curable coating composition of the invention comprises a film-forming component A) comprising one or more monomers, one or more oligomers and/or one or more polymers having one or more radiation crosslinkable ethylenically unsaturated bonds. The summed amount of said film-forming component A) and said salt B) is preferably at least 50 wt.%, more preferably at least 55 wt.%, more preferably at least 60 wt.%, more preferably at least 65 wt.%, more preferably at least 70 wt.%, more preferably at least 75 wt.%, more preferably at least 80 wt.%, more preferably at least 85 wt.%, more preferably at least 90 wt.% by weight of the coating composition.

Said film-forming component A) preferably comprises

A.1) one or more oligomers having at least one, preferably at least two radiation crosslinkable ethylenically unsaturated bonds, and A.2) one or more reactive diluent component having at least one radiation crosslinkable ethylenically unsaturated bond.

“Reactive” means the ability to form a chemical reaction, preferably a polymerization reaction. As such, a reactive component will be said to possess at least one reactive, or functional, group. In the present invention the reactive diluent component is able to react in the radiation curing reaction with the oligomer. A “diluent” means a substance which reduces the viscosity of the greater composition into which it is added or with which it is associated. A variety of diluents are used to maximize the flowability, and in turn the processability, of the compositions with which they are associated.

Said oligomers A.1) comprises at least one radiation crosslinkable ethylenically unsaturated bond, preferably at least two radiation crosslinkable ethylenically unsaturated bonds. Said oligomers A.1) preferably comprises (meth)acryloyl groups. Preferably oligomers A.1) comprises from 2 to 6 (meth)acryloyl groups, more preferably said oligomers A.1) comprises from 2 to 3 (meth)acryloyl groups.

Said oligomers A.1) are preferably present in an amount of from 20 to 70 wt.%, more preferably from 30 to 60 wt.% by weight of A). Said oligomers A.1) are more preferably present in an amount of from 20 to 70 wt.%, more preferably from 30 to 60 wt.% by weight of A.1) + A.2).

Said oligomers A.1) preferably have a number average molecular weight Mn from 300 to 10,000 g/mol, more preferably 400 to 5,000 g/mol and most preferably 500 to 2,000 g/mol. Number average molecular weights may be determined by Gel Permeation Chromatography using polystyrene standards when tetra hydrofuran is used as eluent, or polymethyl methacrylate standards when hexafluoroisopropanol (HFIP) is used as eluent.

Said oligomers A.1) are preferably selected from the group consisting of urethane (meth)acrylates, polyester (meth)acrylates, epoxy (meth)acrylates, (meth)acrylated (meth)acrylic oligomers and any mixture thereof.

Polyester (meth)acrylate oligomers are well known. These (meth)acrylated polyesters can be obtained by reacting a hydroxyl group-containing polyester backbone with (meth)acrylic acid, or by reacting a carboxyl group-containing polyester backbone with a hydroxyalkyl (meth)acrylate such as for example 2-hydroxyethyl acrylate, 2- or 3-hydroxypropyl acrylate, etc. or with glycidyl (meth)acrylate. The polyester backbone can be obtained in a conventional manner by polycondensation of at least one polyhydroxy alcohol, such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol, trimethylolpropane, bisphenol A, pentaerythritol, etc, and/or the ethoxylates and/or propoxylates thereof, with at least one polycarboxylic acid or anhydride thereof such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, etc. By using unsaturated compounds for the polyester synthesis, such as for example fumaric acid, maleic acid, itaconic acid, etc., polyesters bearing both (meth)acrylic and ethylenic unsaturations in the polymer chain, can be obtained. In addition polylactones and/or polylactides can be used as polyester backbone. For example poly(e-caprolactone), polylactide and/or poly(lactide, caprolactone) can be obtained by ring-opening polymerization of e-caprolactone and/or lactide optionally in the presence of one or more polyhydroxy alcohols. Examples of suitable polyester (meth)acrylates include AgiSyn™ 705, AgiSyn™ 707 AgiSyn™716, AgiSyn™720, AgiSyn™730, AgiSyn™740,NeoRad™P-11, NeoRad™ P50, NeoRad™ P-56 available from DSM.

(Poly)urethane (meth)acrylate oligomers can be prepared by reacting a di- and/or polyisocyanate, such as hexamethylene-diisocyanate, isophorone-diisocyanate, toluenediisocyanate, with hydroxyl functional (meth)acrylate. Use can be made exclusively of hydroxyl functional (meth)acrylates such as those mentioned above, but in order to extend the chain, mono- or polyhydroxy alcohols can also be added. Examples of suitable urethane (meth)acrylates include AgiSyn™ 230T1, AgiSyn™ 230A2, AgiSyn™ 230S1-B85, NeoRad™ U-10-15T, NeoRad™ U-20-12H, NeoRad™ all available from DSM. Examples of suitable aromatic urethane (meth)acrylates: AgiSyn™ 670T1, NeoRad™ U60, NeoRad™ U-61 , all available from DSM.

By epoxy (meth)acrylate oligomers is meant to designate the (meth)acrylic esters of epoxides, preferably polyepoxides, i.e. compounds comprising at least one, preferably at least two epoxide functions. Epoxy (meth)acrylate oligomers are generally obtained from the esterification reaction of (meth)acrylic acid with epoxides. The epoxides are generally chosen from epoxidized olefins, glycidyl esters of saturated or unsaturated carboxylic acids, glycidyl ethers of aromatic or aliphatic alcohols or polyols and from cycloaliphatic polyepoxides. Preferred epoxides are diglycidylethers of aromatic and aliphatic diols and cycloaliphatic diepoxides such as diglycidyl ether of bisphenol-A, diglycidyl ether of bisphenol-F, diglycidylether of poly(ethylene oxide-co-propylene oxide), diglycidylether of polypropylene oxide, diglycidylether of hexanediol, diglycidylether of butanediol. Particularly preferred is diglycidyl ether of bisphenol-A. Also epoxidized natural oils or epoxidized phenol-formaldehyde copolymers can be used. Examples of natural oils include soybean oil, linseed oil, perilla oil, fish oil, dehydrated castor oil, tung oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, palm kernel oil, peanut oil, sunflower oil, safflower oil, castor oil. Examples of suitable epoxy (meth)acrylates include AgiSyn™ 1010, AgiSyn™1030, AgiSyn™1050 , AgiSyn™ 2020, AgiSyn™ 3050, AgiSyn™ 3051 all available from DSM. (Meth)acrylated (meth)acrylic oligomers can be obtained by first preparing a (meth)acrylic copolymer by copolymerization of (meth)acrylate monomers such as butyl acrylate with monomers containing pendant carboxylic acid, anhydride, hydroxy, glycidyl or isocyanate groups and by then reacting this copolymer with a monomer comprising at least one (meth)acrylate functional group and at least one carboxylic acid, anhydride, hydroxyl, glycidyl or isocyanate reactive groups. For example, a glycidyl group-containing copolymer can first be prepared by copolymerizing functionalized monomers such as glycidyl (meth)acrylate with other (meth)acrylate monomers, the said glycidyl group-containing polymer being usually reacted in a second step with (meth)acrylic acid. When the functionalized monomers are (meth)acrylic acid, the carboxyl group-containing polymer is generally reacted in the second step with glycidyl (meth)acrylate. Examples of suitable (meth)acrylated (meth)acrylic are AgiSyn™ 9790, NeoRad™ A-20 all available from DSM.

More preferably said oligomers A.1) are urethane (meth)acrylates. The urethane (meth)acrylate is preferably the reaction product of at least i) at least one organic polyisocyanate, ii) at least one organic isocyanate-reactive polyol, iii) a hydroxyl group containing (meth)acrylate compound

The polyisocyanate compound used to prepare the urethane (meth)acrylate A.1) is preferably a diisocyanate compound. Preferably, the diisocyanate compound comprises, consists essentially of, or consists of isophorone diisocyanate, 2,4-isomer toluene diisocyanate, 2,4- and/or 4, 4'-methylenedicyclohexyl diisocyanate, methylenediphenyl diisocyanate , tetramethylxylene diisocyanate, (hydrogenated) xylylene diisocyanate, 1,5- pentane diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, 2,4,4-trimethyl- hexamethylene diisocyanate, or hexamethylene diisocyanate, or mixtures thereof. Examples of suitable polyol compounds to prepare the urethane (meth)acrylate A.1) include polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, acrylic polyols, and other polyols. These polyols may be used either individually or in combinations of two or more.

The hydroxyl-group containing (meth)acrylate compound used to prepare the urethane (meth) acrylate A.1) are for example 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and hydroxyethylcaprolactone(meth)acrylate. The hydroxyl-group containing (meth)acrylate compound used to prepare the urethane (meth)acrylate A.1) is preferably 2- hydroxyethyl methacrylate and/or 2-hydroxyethyl acrylate. The most preferred hydroxylgroup containing (meth)acrylate compound comprises, consists essentially of, or consists of 2-hydroxyethyl acrylate.

Said reactive diluents A.2) comprises at least one radiation crosslinkable ethylenically unsaturated bond, preferably at least two radiation crosslinkable ethylenically unsaturated bonds. Said reactive diluents A.2) preferably comprises (meth)acryloyl groups. Preferably reactive diluents A.2) comprises at least 2 (meth)acryloyl groups, more preferably said reactive diluents A.2) comprises at least 3 (meth)acryloyl groups.

Said reactive diluents A.2) are preferably present in an amount of from 30 to 80 wt.%, more preferably from 40 to 70 wt.% by weight of A). Said reactive diluents A.2) are more preferably present in an amount of from 30 to 80 wt.%, more preferably from 40 to 70 wt.% by weight of A.1) + A.2).

Said reactive diluents A.2) preferably have a number average molecular weight Mn from 100 to 1 ,000 g/mol, more preferably from 200 to 800 g/mol and most preferably from 200 to 500 g/mol. Number average molecular weights may be determined by Gel Permeation Chromatography using polystyrene standards when tetra hydrofuran is used as eluent, or polymethyl methacrylate standards when hexafluoroisopropanol (HFIP) is used as eluent Said reactive diluents A.2) include for example multifunctional (meth)acrylate monomers such as (meth)acrylic acid esters of mono-, di- and tri- hydroxyl alcohols (e.g. polyethylene glycol, polypropylene glycol, aliphatic diols, ethylene glycol, neopentyl glycol, ethoxylated bisphenol A, trimethylolpropane, di-trimethylolpropane, pentaerythritol, dipentaerythritol, glycerol, propoxylated glycerol, and all other ethoxylated and propoxylated monomers; 2- phenoxy ethylacrylate (PEA), glycerol propoxylate triacrylate (GPTA), neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate (TMPTA), ethoxylated trimethylolpropane tri(meth)acrylate (TMPTA3EO, TMPTA6EO), pentaerythritol tri(meth)acrylate and tetra(meth)acrylate, caprolactone (meth)acrylates, alkoxylated (meth) acrylates, glycerol (meth)acrylates, 1,4-butanediol di(meth)acrylate, 1,6-hexane diol di(meth)acrylate (HDDA), ethoxylated 1,6-hexane diol di(meth)acrylate (HDDA2EO),

2.2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropio nate di(meth)acrylate, isobornyl (meth)acrylate, dipropylene glycol diacrylate (DPGDA), tripropylene glycol di(meth)acrylate (TPGDA) and the like.

Said reactive diluents A.2) are preferably selected from the group consisting of trimethylolpropane tri(meth)acrylate (TMPT(M)A), pentaerythritol tri- and/or tetraacrylate (PET A), 1,6-hexane diol diacrylate (HDDA), neopentyl glycol di(meth)acrylate (NPGD(M)A), glycerol propoxylate triacrylate (GPTA), ethoxylated trimethylolpropane tri(meth)acrylate (TMPT(M)A3EO, TMPT(M)A6EO), tripropylene glycol di(meth)acrylate (TPGD(M)A) and any mixture thereof.

The radiation curable coating composition of the invention can comprise one or more photoinitiators that can cause photopolymerization upon radiation. If the radiation curable coating composition of the invention comprise one or more photo-initiators, they are included in an amount sufficient to obtain the desired cure response. Typically, the one or more photoinitiators are included in amounts in a range of from 1 to 15% by weight of the coating composition. Preferably, the one or more photo-initiators are present in an amount, relative to the entire weight of the coating composition, of from 1 wt.% to 10 wt.%, more preferably from 2 wt.% to 8 wt.% and even more preferably from 2 wt.% to 7 wt.%. Suitable photoinitiators include, but are not limited to, bisacylphosphine oxides, such as for example bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (CAS# 162881-26-7) or is bis(2,4,6- trimethylbenzoyl)-(2,4-bis-pentyloxyphenyl)phosphine oxide; monoacylphosphine oxide, such as for example 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide (CAS# 84434-11- 7) or 2,4,6-trimethylbenzoyldiphenylphosphine oxide (CAS# 127090-72-6); ketals such as

2.2-dimethoxy-1,2-diphenylethan-1-one (CAS# 24650-42-8); benzophenones such as benzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 2- methylbenzophenone, 2-methoxycarbonylbenzophenone, 4-phenylbenzophenone, 4,4'- bis(dimethylamino)-benzophenone, 4,4'-bis(diethylamino)benzophenone, methyl2- benzoylbenzoate, 3,3'-dimethyl-4-methoxybenzophenone, 4-(4- methylphenylthio)benzophenone, 2,4,6-trimethyl-4'-phenyl-benzophenone or 3-methyl-4'- phenyl-benzophenone.

Additives are also typically added to coating compositions to achieve certain desirable characteristics such as improved shelf life, improved coating oxidative and hydrolytic stability, and the like. Examples of typical additives include antioxidants, activators (accelerants), thermal inhibitors, fillers, pigments, dyes, antistatics, flame retardants, light stabilizers, heat stabilizers, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, adhesion promotors, photosensitizer, carrier surfactant, tackifier, catalyst, surface agents, optical brighteners or plasticizers.

To accelerate photopolymerization it is possible to add other additives such as accelerators, coinitiators and autoxidizers.

Additives can be employed in compositions according to the present invention in any suitable amount. In a preferred embodiment, the additives are present in an amount, relative to the entire weight of the composition, of from about 0.01 wt.% to about 40 wt.%, more preferably from about 0.1 wt.% to about 20 wt.%. According to another embodiment, the additives are included in an amount from about 1 wt.% to about 5 wt.%.

The present invention is further directed to a substrate coated with the aforementioned antiviral coating layer. The coating composition according to the invention may be applied to a wide variety of substrates. Preferred substrates are wood, optionally containing a primer and a midcoat, engineered wood, metal, textile, yarn, thermoplastic polymer (for instance polypropylene, polyethylene, polycarbonate, polyamide, polystyrene), thermoset polymer , plastic foils (for instance polypropylene or polyvinyl chloride or polyethylene terephthalate), leather, glass, ceramic, natural stone, agglomerated stone, fiber cement board, hybrid polymer composite material, paper or a combination of at least two of these materials. A substrate having one or more coating layers can also be suitable. Preferably the substrate is or comprises a layer of wood, engineered wood, metal, thermoplastic polymer, thermoset polymer, glass, ceramic, natural stone, agglomerated stone, fiber cement board, hybrid polymer composite material, and combinations thereof.

The antiviral coating layer of the present invention is preferably the outer most coating layer on the substrate. In a preferred embodiment of the invention, the substrate is preferably a plastic, paper or metal substrate (or a substrate of a combination of any of plastic, paper and metal), and the coated substrate is used as a packaging material advantageously to be used for consumer products. The coating then preferably has a film thickness of 1.0 pm to 5 pm.

The present invention is further directed to a process for forming an anti-viral coating layer on a substrate. The process can comprise the steps of:

(i) providing a radiation curable coating composition as described above; (ii) applying said radiation curable coating composition over a substrate to form a liquid coating layer; and

(iii) radiation curing said liquid coating layer to form said anti-viral coating layer on said substrate.

The present invention is also directed to an anti-viral coating layer formed from the radiation curable coating composition as described above.

The coating can be applied in various ways, such as spraying, brushing, roll-to-roll, dipping, curtain coating, printing (flexo, gravure). The coating compositions according to the invention can advantageously be used in packaging, in printing applications such as overprint varnishes, for furniture, for parquet flooring, for flexible flooring (such as PVC, linoleum), for decorative paints, for wall coatings, for plastic shopping carts, for door-handles, for handrails and for counters.

The present invention further relates to the use of the radiation curable coating composition or of the coating described above or prepared with the method as described above for inactivating enveloped viruses.

The present invention further relates to a method for inactivating enveloped viruses present on a coating or that come into contact with a coating, comprising

(i) providing a coating composition as described above on a substrate,

(ii) curing the coating composition to obtain a coated substrate,

(iii) inactivating enveloped viruses present on the coating of the coated substrate and/or inactivating enveloped viruses, that come into contact with the coating of the coated substrate.

The present invention is now illustrated by reference to the following example. Unless otherwise specified, all parts, percentages and ratios are on a weight basis.

Examples

Abbreviations

AgiSyn 230A4 urethane hexa-acrylate in 5 % 1,6-hexane diol diacrylate NeoRad U-10-15H polyether based urethane tri-acrylate in 15 % 1,6-hexane diol diacrylate

AgiSyn 2816 (HDDA) 1 ,6-hexanediol diacrylate

AgiSyn 2815 (TPGDA) tripropyleneglycol diacrylate

Omnirad 1173 photo initiator, 2-hydroxy-2-methyl-1 -phenylpropanone

Omnirad 500 photo initiator; Blend of Benzophenone + 1-Hydroxycyclohexyl- phenyl ketone

Omnipol BP photo-initiator, di-ester of carboxymethoxy-benzophenone and polytetramethyleneglycol 250

DMAEMA dimethyl aminoethyl methacrylate

AgiSyn 2811 (TMPTA) trimethylolpropane triacrylate

AgiSyn 2896 (LA) lauryl acrylate

Phosphated HEMA phosphated hydroxyethyl methacrylate

NeoRad U-65 polyether based urethane hexa-acrylate in 20 % dipropylene glycol diacrylate

AgiSyn 2833 (DPGDA) dipropylene glycol diacrylate

Vikureen ABS acrylonitrile-butadiene-styrene

Vinplast PVC polyvinyl chloride

Example 1

An UV curable formulation was prepared by mixing 42 g NeoRad U-10-15H (polyether based urethane acrylate in 15 % 1,6-hexane diol diacrylate, obtained from DSM Coating Resins), 37 g tripropyleneglycol diacrylate (AgiSyn 2815, obtained from DSM Coating Resins), 7g trimethylolpropane triacrylate (AgiSyn 2811, obtained from DSM Coating Resins). The mixture was stirred with a mechanical overhead stirrer and 5 g of dimethyl aminoethyl methacrylate (DMAEMA, purchased at Evonik) was added followed by 6.3 g lauric acid (solid, purchased at Sigma Aldrich). The mixture was stirred at room temperature until the formed salt was dissolved in the UV formulation and a clear and transparent solution was obtained.

The solution was further mixed with 5 g Omnirad 500 Photo initiator (purchased at IGM Resins) and 4 g methyldiethanolamine co-initiator (MDEA, purchased at Sigma Aldrich). The calculated amount of NIT'OOC in the solution is 0.3 mmol NIT'OOC/g coating composition. The NIT'OOC concentration is calculated on the lowest concentration (in mmol) of carboxylic acid or of tertiary amine that is added to the coating composition and hence in this example the NI 'OOC concentration is calculated on the concentration of carboxylic acid.

The UV curable formulation was applied to a Leneta card 2C at 12 pm layer thickness with a wire rod and was cured with a UVio curing rig with a conveyor belt speed of 15 m/min by a Light Hamer 10 Mark II equipped with a H-bulb operating @ 100 % power (Heraeus Holding, Hg doped UV lamp generating UV light with wave lengths > 300 nm, 1 J/cm ² total dose as determined with a Power Puck II (EIT Inc)) in a nitrogen atmosphere (02 level < 50 ppm detected with IOT inline detector).

Chemical resistance tests and water spot test

The cured coating was subjected to the following chemical resistance tests and water spot test. The coating was evaluated for damage done to the coating. A rating of 5 was given to coatings without any visual damage, while a rating of 1 was given to coatings that were severely damaged.

5= excellent, no impairment, 4 = very good, hardly impaired, 3 = good, minor impairment, 2= moderate, impaired and 1 = poor, severely damaged

Chemical resistance was tested by applying MEK rubs on the cured coating based on ASTM D-4752. The coating was rubbed 200 times and showed no damage (score 5).

Additionally a 16 h ethanol spot test was done with 48 % ethanol in water based on DIN 68861-1 :2011-01 standard. A cotton cloth of 1*1 cm was soaked in the 48% ethanol until it was saturated and placed on the coating and covered with a glass cover to minimize evaporation of the ethanol. After 16 hours the glass cover and cotton cloth are removed from the coating, after which the stain was cleaned with water and a paper towel and damage to the coating was assessed. The coating scored a 4.

Additionally a 16 h water spot test was done based on DIN 68861-1:2011-01. A cotton cloth of 1*1 cm was soaked in water until it was saturated and placed on the coating and covered with a glass cover to minimize evaporation of the water. After 16 hours the glass cover and cotton cloth are removed from the coating, after which the stain was cleaned with water and a paper towel and damage to the coating was assessed. The coating scored a 5.

Preparation of the Michael adduct of HDDA and ethanolamine 84 grams of Agisyn 2816 (HDDA = hexanedioldiacrylate) was added into a reactor, under nitrogen. 400ppm of phenothiazine as stabilizer was added into the reactor. The reactor was heated to 50°C and 15 grams of ethanolamine was slowly added to the reactor and then maintained at 50°C for 1h. Then the reactor was heated to 70°C and maintained for 6 hours. The reactor was cooled down to room temperature.

Examples 2-3 and Comparative Experiment A

UV curable formulations were prepared and cured according to the procedures described under Example 1 , with the compositions as depicted in Table 1. The calculated amount of NIT'OOC in the solution is also reported in Table 1.

Table 1 Comparative Experiments B-C and Examples 4-5

UV curable formulations were prepared and cured according to the procedures described under Example I, with the compositions as depicted in Table 2. Table 2

The UV curable formulation was applied to a Leneta card 2C at 12 pm layer thickness with a wire rod.

Comparative Experiment B and Example 4 were cured with a UVio curing rig with a conveyor belt speed of 15 m/min by a Light Hamer 10 Mark II equipped with a H-bulb operating @ 100 % power (Heraeus Holding, Hg doped UV lamp generating UV light with wave lengths >300 nm, 1 J/cm ² total dose as determined with a Power Puck II (EIT Inc)) in a nitrogen atmosphere (O2 level < 50 ppm detected with IOT inline detector).

Comparative Experiment C and Example 5 were cured on a UVio curing rig with a conveyor belt speed of 15 m/min equipped with 2 lamps. The first Lamp was a Excirad 172 lamp (IOT GmbH, xenon based excimer lamp generating 172 nm light) under which the cure was performed with a radiation dose of 6.9 mJ/cm ² (determined with an ExciTrack172, IOT GmbH) in a nitrogen atmosphere (O2 level < 50 ppm detected with IOT inline detector). The next cure step was performed by the second lamp being a Light Hamer 10 Mark II equipped with a H-bulb operating @ 100 % power (Heraeus Holding, Hg doped UV lamp generating UV light with wave lengths > 300 nm, 1 J/cm ² total dose as determined with a Power Puck II (EIT Inc)) in air.

Antiviral testing

Antiviral properties of coatings were tested according to ISO21702:2019(E), using PHI6 bacteriophages as virus and Pseudomonas syringae as host cells. Coatings were applied with a 12 pm film thickness on Leneta charts 2C. Sample pieces of 3*3 cm ² were cut out to which 10 ⁷ viruses were applied. After a contact time of 6 hours, the remaining viruses were transferred to host cells. Deactivation rate of the viruses was reported as a ¹⁰ log-reduction or deactivation rate in percentages.

Table 3: Antiviral test results

Example 6

An UV curable formulation was prepared by mixing 42 g NeoRad U-10-15H (polyether based urethane acrylate in 15 % 1 ,6-hexane diol diacrylate, obtained from DSM Coating Resins) and 37 g tripropyleneglycol diacrylate (AgiSyn 2815, obtained from DSM Coating Resins). The mixture was stirred with a mechanical overhead stirrer and 5 g of dimethyl aminoethyl methacrylate (DMAEMA, purchased at Evonik) was added followed by 6.37 g lauric acid (solid, purchased at Sigma Aldrich). The mixture was stirred at room temperature until the formed salt was dissolved in the UV formulation and a clear and transparent solution was obtained.

The solution was further mixed with 5 g Omnirad 500 Photo initiator (purchased at IGM Resins) and 4 g methyldiethanolamine co-initiator (MDEA, purchased at Sigma Aldrich). The calculated amount of NIT 'OOC in the solution is 0.32 mmol NIT 'OOC/g coating composition.

The UV curable formulation was applied to a Leneta card 2C at 12 pm layer thickness with a wire rod and was cured with a UVio curing rig with a conveyor belt speed of 15 m/min by a Light Hamer 10 Mark II equipped with a H-bulb operating @ 100 % power (Heraeus Holding, Hg doped UV lamp generating UV light with wave lengths > 300 nm, 1 J/cm ² total dose as determined with a Power Puck II (EIT Inc)) in a nitrogen atmosphere (02 level < 50 ppm detected with IOT inline detector).

The antiviral test result of the coating was a ¹⁰ log reduction of 4.88, corresponding to 99.99% deactivation.

The coating was thoroughly cleaned using ammonia:

The cured coating was washed with a 12.5 v/v-% solution of ammonia in water.

The coating was rubbed 10 times horizontally with a wad of cotton drenched in the ammonia solution, followed by 10 vertical rubs. After drying of the coating, the coating was rubbed 10 times with a wad of cotton drenched in water after which the coating was dried with a piece of paper. The antiviral activity of the coating was tested again: The antiviral test result of the coating was a ¹⁰ log reduction of 4.78, corresponding to 99.99% deactivated.

Chemical resistance tests and water spot test

The cured coating was subjected to the following chemical resistance tests and water spot test. The coating was evaluated for damage done to the coating. A rating of 5 was given to coatings without any visual damage, while a rating of 1 was given to coatings that were severely damaged.

5= excellent, no impairment, 4 = very good, hardly impaired, 3 = good, minor impairment, 2= moderate, impaired and 1 = poor, severely damaged

Chemical resistance was tested by applying MEK rubs on the cured coating based on ASTM D-4752. The coating was rubbed 200 times.

The other stain tests are based on DIN 68861-1 :2011-01 standard. Liquids were applied to the cured coating by saturating a cotton cloth of 1*1 cm with the individual test fluids. For mustard no cloth was used because of viscosity, but an equal amount was applied directly to the coating instead. After applying each test chemical, a glass cover was placed over the test chemical in order to prevent evaporation of liquids. For the 6 h and 24 h stains: After the specified amount of time had passed, the chemical and disc were removed from the coating, after which the stain was cleaned with water and a paper towel. The stain was rated on a scale of 0 to 5, where 5 is no visual stain and 0 is a severe stain. For the 2 h stains: After the specified amount of time had passed, the chemical and disc were removed from the coating, after which the stain was cleaned with isopropyl alcohol and a paper towel. The stain was rated on a scale of 0 to 5, where 5 is no visual stain and 0 is a severe stain. Water and chemical resistances of the coatings are reported in Table 4 and 5.

Table 4

Table 5 Adhesion results

Coatings were applied with a 12 pm film thickness on plastic based panels which have been cleaned with I PA (iso-propyl alcohol) and a tissue to remove any dirt and grease. Adhesion on 3mm thick Vikureen PVC (Polyvinyl chloride obtained from Vink Kunstoffen) and 3mm thick Vinplast ABS (Acrylonitrile-butadiene-styrene obtained from Vink Kunstoffen) was tested immediately after curing by making a crosshatch with a Gitterschnitt (Byk 5126), after which a piece of 3M Scotch 600 tape was applied on the crosshatch. The tape was firmly pressed down with the back of a spatula to remove excess air bubbles and pulled off in one fluid motion. The area was then rated on a scale of 0 to 5, where 5 equals none of the coating was removed and 0 means that all the coating within the crosshatch was removed. Adhesion results are shown in Table 6

Table 6