Monomer mixtures comprising N-vinyl monomers and butenolide monomers and coating compositions derived therefrom

Abstract

A radiation curable coating composition comprising a monomer mixture comprising: a) at least one butenolide monomer A which is a substituted 5-hydroxy-2 (5H)-furanone of general formula (I) wherein n is 0 or an integer from 1 to 5; m is 0 or 1; r1 is alkyl or aryl; x is any one of-C (O)-,-C (O) O-,-C (O) NR2-,-S (O)-,-S (O2)-,-C (O) S-,-C (S) S-, and-C (S) NR2-; wherein R2 is hydrogen, alkyl or aryl; and b) at least one N-vinyl monomer B which is a compound of general formula (II) wherein R4 and R5 are each independently any of hydrogen, alkyl, aryl, heteroalkyl or heteroaryl and Y is selected from O, NR6 and S; and wherein i) a is 1 and b is 1; or ii) a is 0 and b is 2; and wherein at least one of the monomers of A and B comprises at least two vinyl groups. # imgabs0 #

Description

Field of the Invention

[0001] The present invention relates to a monomer mixture comprising an N-vinyl monomer and a butenolide monomer. It also relates to a radiation-curable coating composition comprising the monomer mixture, a base polymer obtainable by polymerizing the monomer mixture, a coating composition comprising the base polymer, and a substrate coated with a coating deposited from the coating composition. Background of the Invention

[0002] Polyacrylates or other addition polymers are widely used as film-forming polymers in paints and coatings. Film-forming polymers are also called binder polymers because they hold together any particulate materials such as color pigments and extenders.

[0003] Radiation-curable coating compositions containing double bonds that can be activated by actinic radiation, such as UV light or electron beam radiation, are well known in the art. Actinic radiation as mentioned herein is electromagnetic, ionizing radiation, especially electron beam radiation, UV light and visible light. Radiation-curable coating compositions are typically crosslinked by free radical polymerization of monomers having ethylenically unsaturated groups, such as acryloyl, methacryloyl or vinyl groups. Examples of such monomers include acrylic acid, methacrylic acid, alkyl (meth)acrylates, styrene, alkyl-substituted styrenes, vinyl esters and vinyl ethers. These monomers are typically prepared from petrochemical raw materials.

[0004] Polyacrylates or other addition polymers are typically prepared by free radical polymerization of monomers containing ethylenically unsaturated groups, such as acrylic acid, methacrylic acid, or vinyl groups. Examples of such monomers include acrylic acid, methacrylic acid, alkyl (meth)acrylates, styrene, alkyl-substituted styrenes, vinyl esters, and vinyl ethers. These monomers are typically prepared from petrochemical feedstocks.

[0005] The demand for chemical products produced from renewable raw materials is constantly increasing. Base polymers produced at least partially from renewable raw materials are known in the art. Alkyd resins, for example, contain relatively high contents of fatty acids derived from vegetable oils.

[0006] WO 2009 / 080599 discloses a process for preparing polymerizable ethylenically unsaturated macromonomers from vegetable oils that can be used to prepare addition polymers for use in coating compositions.

[0007] In US 4,954,593 a copolymer for use as a protective coating is disclosed which is prepared by combining a furanone monomer and a vinyl ether monomer in a molar ratio of about 1. The copolymer can be prepared by photopolymerization or by solution polymerization in the presence of a free radical initiator.

[0008] Butenolides are olefinically unsaturated furanic compounds that can be prepared from carbohydrates, i.e., renewable raw materials. Carbohydrate raw materials such as starch, cellulose, or carbohydrate-containing biowaste can be converted into furfural, hydroxymethylfurfural, or related furan derivatives by dehydration and subsequently oxidized to lactones or other butenolides. The preparation of butenolides is described, for example, in JC de Jong, Asymmetric Diels-Alder reactions with 5-menthyloxy-2(5H)-furanones, Chapter II, Thesis University of Groningen, 2006, which can be accessed at https: / / www.rug.nl / research / portal / en / publications / asymmetric-dielsalder-reactions- with-5menthyloxy25hfuranones(f0ab6c00-8c6c-4ccc-90aa-3ef05f759fa4).html .

[0009] Poskonin et al. have disclosed in Russian Journal of Organic Chemistry 35 (1999) 721-726 a copolymer prepared by free radical polymerization of 4-alkoxy-2-butenoic acid lactone (5-alkoxy-2 (5H)-furanone) and styrene, methyl methacrylate or vinyl acetate. The purposes of such copolymers in the synthesis of physiologically active substances have been proposed. Poskonin et al. have further disclosed in Russian Journal of Organic Chemistry 35 (1997) 520-523 an oligomer prepared by free radical polymerization of 4-acetoxy-2-butenoic acid lactone (5-acetoxy-2 (5H)-furanone) and styrene, methyl methacrylate or vinyl acetate. A number average molecular weight of 1860-6460 has been achieved.

[0010] WO 2021 / 084066 describes the copolymerization of 5-alkoxy-2(5H)-furanone with selected vinyl ethers or vinyl esters and the use of the resulting copolymers as binders in polymer coating compositions.

[0011] WO 2021 / 259819 describes a radiation-curable copolymer coating composition comprising a 5-hydroxy- or 5-alkoxy-2(5H)-furanone compound and a compound having two or more vinyl ether or vinyl ester groups.

[0012] Trost and Toste have disclosed in J. Am. Chem. Soc. 2003, 125, 3090-3100 two butenolide compounds for introducing chirality into the synthesis of aflatoxins: 2-tert-butoxycarbonyloxy-5-oxo-2,5-dihydrofuran and 2-benzoyloxy-5-oxo-2,5-dihydrofuran.

[0013] US 3,929,735 describes a copolymer of an N-vinyl lactam, such as N-vinyl-2-pyrrolidone, and an unsaturated lactone, such as butenolide. It does not mention the use of the copolymer in a radiation-curable coating composition.

[0014] There is a need for coating compositions which can be obtained at least partly from renewable raw materials and which have a higher reactivity and additional functional groups compared to known binder polymers. SUMMARY OF THE INVENTION

[0015] It has now been discovered that hard and chemically resistant cured coatings can be obtained by radiation curing compositions comprising 5-substituted butenolide monomers and monomers containing one or more N-vinyl groups, the radiation curing being activated by actinic radiation, such as visible or UV light, or electron beam radiation. The resulting coatings have properties that make them suitable as protective or decorative coatings. In addition, hard coatings can be deposited from coating compositions comprising a binder obtainable by copolymerizing a mixture of a 5-substituted butenolide monomer and a monomer containing one or more N-vinyl groups.

[0016] Thus, the present invention provides, in a first aspect, a radiation curable coating composition comprising a monomer mixture comprising:

[0017] a) at least one butenolide monomer A, which is a substituted 5-hydroxy-2(5H)-furanone of the general formula (I):

[0018]

[0019] n is 0 or an integer from 1 to 5;

[0020] m is 0 or 1;

[0021] R 1 is an alkyl group or an aryl group;

[0022] X is -C(O)-, -C(O)O-, -C(O)NR 2 -, -S(O)-, -S(O2)-, -C(O)S-,

[0023] -C(S)S- and -C(S)NR 2 -Any one of; wherein R 2 is hydrogen, alkyl or aryl;

[0024] Or when n is 0, R 1 and R 2 Together with the nitrogen atom via which they are attached, they form a nitrogen-containing heterocyclic group or a nitrogen-containing heteroaryl group; and b) at least one N-vinyl monomer B which is a compound of the general formula (II):

[0025]

[0026] where R 4 and R 5 are each independently any one of hydrogen, alkyl, aryl, heteroalkyl or heteroaryl and Y is selected from O, NR 6 and S; where R 6 is hydrogen, alkyl, aryl, heteroalkyl or heteroaryl; wherein R 4 、R 5 and R 6 Any two of the group, taken together with the atoms through which they are attached, form a nitrogen-containing cyclic heteroalkyl group or a nitrogen-containing heteroaryl group; and wherein i) a is 1 and b is 1; or ii) a is 0 and b is 2;

[0027] wherein at least one monomer of A and B comprises at least two vinyl groups; and wherein the coating composition does not contain a compound having two or more acryloyl or methacryloyl groups.

[0028] In a second aspect, the present invention provides a monomer mixture comprising:

[0029] a) at least one butenolide monomer A, which is a substituted 5-hydroxy-2(5H)-furanone of the general formula (I):

[0030]

[0031] n is 0 or an integer from 1 to 5;

[0032] wherein when n is 0, m is 1 and when n is an integer from 1 to 5, m is 0 or 1;

[0033] R 1 is an alkyl group or an aryl group;

[0034] X is -C(O)-, -C(O)O-, -C(O)NR 2 -, -S(O)-, -S(O2)-, -C(O)S-, -C(S)S-, and -C(S)NR 2 -Any one of; wherein R 2 is hydrogen, alkyl or aryl;

[0035] Or when n is 0, R 1 and R 2 Together with the nitrogen atom via which they are attached, they form a nitrogen-containing heterocyclic group or a nitrogen-containing heteroaryl group; and b) at least one N-vinyl monomer B which is a compound of the general formula (II):

[0036]

[0037] where R 4 and R 5 are each independently any one of hydrogen, alkyl, aryl, heteroalkyl or heteroaryl and Y is selected from O, NR 6 and S; where R 6 is hydrogen, alkyl, aryl, heteroalkyl or heteroaryl; wherein R 4 、R 5 and R 6 Any two of together with the atoms through which they are attached form a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl; and wherein i) a is 1 and b is 1; or ii)

[0038] a is 0 and b is 2.

[0039] In a third aspect, the present invention provides a base polymer obtainable by copolymerizing a monomer mixture as defined herein.

[0040] In a fourth aspect, the present invention provides a coating composition comprising a binder polymer as defined herein.

[0041] In a fifth aspect, the present invention provides a substrate coated with a coating deposited from a radiation curable coating composition or a coating composition as defined herein.

[0042] It has been found that the binder polymer, when applied to a substrate and allowed to dry, provides a tack-free coating film having good hardness properties.

[0043] The base polymer has a polymer backbone with functional groups which advantageously offer the possibility of crosslinking, for example with hydroxyl- or thiol-functional crosslinking agents or with polymers having hydroxyl- or thiol-functional groups. Detailed description

[0044] The radiation-curable coating composition comprises a) one or more butenolide monomers A; and b) one or more vinyl monomers B, wherein at least one of A and B comprises at least two vinyl groups. The presence of the monomer having at least two vinyl groups is necessary for its use as a crosslinker in the coating composition.

[0045] The base polymer can be obtained by copolymerizing a monomer mixture comprising at least one butenolide monomer A and at least one N-vinyl compound B.

[0046] As used herein, the term "one or more" with respect to each of A and B means that multiple different monomers of A and B, respectively, may be present in the coating composition. For example, a composition may include one butenolide monomer A and one vinyl monomer B. Alternatively, it may include one butenolide monomer A and two vinyl monomers B, the vinyl monomers B being different from each other. Alternatively, it may include two butenolide monomers A and one butenolide monomer B, the butenolide monomers A being different from each other.

[0047] The vinyl group has an α-C and a β-C determined by the proximity to another functional group in the molecule. As used herein, the distance between the α-C and β-C of the vinyl group is 13 The C chemical shift difference can be determined from the chemical shift reported in the Organic Compound Spectral Database managed by the National Institute of Advanced Industrial Science and Technology (https: / / sdbs.db.aist.go.jp / sdbs / cgi-bin / direct_frame_top.cgi).

[0048] Alkyl groups used herein can be branched, unbranched, linear or cyclic. The alkyl group can be saturated or unsaturated. It can be substituted or unsubstituted. The alkyl group typically contains 1 to 20 carbon atoms, especially 1 to 12 carbon atoms, 1 to 6 carbon atoms or 1 to 4 carbon atoms. The alkyl group can contain 2 to 20 carbon atoms, especially 2 to 12 carbon atoms, 2 to 6 carbon atoms or 2 to 4 carbon atoms. The alkyl group can contain 1 to 3 carbon atoms, for example 1, 2 or 3 carbon atoms. Examples of alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, isobutyl, hexyl, lauryl, oleyl and cyclohexyl.

[0049] As used herein, cycloalkyl refers to a cyclic alkyl group. A cyclic heteroalkyl group refers to a cycloalkyl group in which at least one carbon in the ring is replaced by a heteroatom. The heteroatom can be nitrogen, oxygen, or another atom other than carbon. A cyclic heteroalkyl group can be a nitrogen-containing cyclic heteroalkyl group.

[0050] As used herein, aryl refers to an aromatic group. Aryl groups can be substituted or unsubstituted. Aryl groups typically contain 6 or 10 carbon atoms. Aryl groups can be phenyl or naphthyl, particularly phenyl. Heteroaryl refers to an aryl group that contains heteroatoms, i.e., atoms other than carbon, in the aromatic ring. Heteroaryl groups can be substituted or unsubstituted. Heteroaryl groups typically contain 5-12 carbon atoms. Typical heteroatoms are oxygen or nitrogen.

[0051] In one embodiment, a is 1 and b is 1. In an alternative embodiment, a is 0 and b is 2.

[0052] R4 is any of hydrogen, alkyl, aryl or heteroalkyl. In one embodiment, R 4 is hydrogen, alkyl or aryl. 4 In particular, it may be hydrogen or C1-C 12 alkyl.

[0053] R 5 Each is independently any of hydrogen, alkyl, aryl or heteroalkyl. In one embodiment, R 5 is hydrogen, alkyl or aryl. 5 In particular, each may be hydrogen or C1-C 12 alkyl.

[0054] Y is selected from O, NR 6 and S; where R 6 is hydrogen, alkyl, aryl, heteroalkyl or heteroaryl. In one embodiment, Y is NR 6 Y can in particular be NR 6 , where R 6 is hydrogen or C1-C 12 alkyl.

[0055] In one embodiment, R 4 、R 5 and R 6 Any two of the alkyl groups, taken together with the atoms through which they are attached, form a nitrogen-containing cyclic heteroalkyl group or a nitrogen-containing heteroaryl group.

[0056] In one embodiment, a is 1, b is 1 and R 4 and R 5 Together with the atoms through which they are attached, they form a nitrogen-containing cyclic heteroalkyl group or a nitrogen-containing heteroaryl group. 4 and R 5 In particular, together with the atoms through which they are attached, they form a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl group and Y is O. For example, R 4 and R 5 Together with the atoms to which they are attached, they form a 5-7 membered cyclic heteroalkyl group comprising one nitrogen atom and 4-6 carbon atoms. In this way, the N-vinyl monomer B is a vinyl lactam, for example, the N-vinyl monomer B can be N-vinylpyrrolidone or N-vinylcaprolactam.

[0057] In one embodiment, a is 1, b is 1, and Y is NR 6 And R 4 and R 6 Together with the atoms through which they are attached, they form a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl group. 4 and R 6Together with the atoms through which they are attached, they form a 5-7 membered heteroaryl group, for example a 5-7 membered heteroaryl group containing 1-2 nitrogen atoms and 3-6 carbon atoms. 5 Can be hydrogen or C1-C 12 Alkyl groups, such as hydrogen. The N-vinyl monomer B may be, for example, N-vinylimidazole.

[0058] In one embodiment, a is 0, b is 2, Y is O and R 5 Each together with the atom through which they are attached forms a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl. 5 Each of the monomers B may form, together with the atoms to which they are attached, a 5-7 membered cyclic heteroalkyl group. The cyclic heteroalkyl group may be annulated, for example, to a phenyl or cyclohexyl group. The fused cyclic heteroalkyl group may be an isoindoline group. The N-vinyl monomer B may be, for example, N-vinylphthalimide, N-vinylsuccinimide or N-vinylmaleimide; in particular, N-vinylphthalimide.

[0059] In one embodiment, the N-vinyl compound B is a monovinyl N-vinyl compound and / or a (meth)acryloyl monomer having a molecular weight in the range of 50-800 g / mol, more preferably 100-500 g / mol.

[0060] In one embodiment, the N-vinyl monomer B has at least two vinyl groups. In the vinyl monomer of formula (II), R 4 or R 5 Contains at least one vinyl group. For example, R 4 Contains at least one vinyl or R 5 Contains at least one vinyl or R 4 and R 5 Both contain at least one vinyl group.

[0061] The radiation curable coating composition may comprise at least two N-vinyl monomers B. At least one N-vinyl monomer B may comprise at least two N-vinyl groups. For example, the radiation curable coating composition may comprise one N-vinyl monomer B that is a monovinyl compound and one N-vinyl monomer B that is a divinyl compound.

[0062] In one embodiment, the N-vinyl monomer B has at least two vinyl groups and is a di-N-vinyl compound.

[0063] Examples of vinyl monomers B having at least two N-vinyl groups are N-vinyl-substituted polycarboxamides, such as adipamide, succinamide, terephthalamide, isophthalamide, trimellitamide.

[0064] The N-vinyl monomer B may have a molecular weight within the range of 100-3,000 g / mol. If the N-vinyl monomer B is a compound having a polymer backbone, the molecular weight is preferably within the range of 500-3,000 g / mol.

[0065] m can each independently be 0 or 1. In the case where m is 0, X is absent. In the case where m is 1, X is present. In one embodiment, especially in the monomer mixtures defined herein, when n is 0, m is 1 and when n is an integer from 1 to 5, m is 0 or 1.

[0066] X is -C(O)-, -C(O)O-, -C(O)NR 2 -, -S(O)-, -S(O2)-, -C(O)S-, -C(S)S-, and -C(S)NR 2 - any one of; wherein R 2 is hydrogen, alkyl or aryl, or when n is 0, R 1 and R 2 Together with the nitrogen atom through which they are attached, they can form a nitrogen-containing heterocyclic group or a nitrogen-containing heteroaryl group. In one embodiment, X is -C(O)-, -C(O)O-, or -C(O)NR 2 -, for example -C(O)-.

[0067] R 1 Can be C1-C 20 In one embodiment, R 1 Can be C2-C 12 Alkyl. R 1 It can be branched or unbranched, substituted or unsubstituted C1-C 12 In another embodiment, R 1 Can be C5-C7 cycloalkyl. In another embodiment, R 1 It may be phenyl.

[0068] In one embodiment, R 3 Can be hydrogen or C1-C 12 Alkyl. R 3 In particular it may be hydrogen.

[0069] n is 0 or an integer from 1 to 5, for example 1, 2, 3, 4 or 5. In particular, n is 0.

[0070] If n is an integer having a value in the range of 1 to 5, the butenolide monomer A is an oligomer obtainable by reacting a multifunctional scaffold having a reactive group in the range of 2 to 6 with 5-hydroxy-2(5H)-furanone. The multifunctional scaffold may, for example, have 1 to 40 carbon atoms.

[0071] Examples of suitable multifunctional scaffolds include diols such as ethylene glycol, propylene glycol, butylene glycol, isosorbide, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, polyethylene glycol, polypropylene glycol, cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, tricyclodecane dimethanol, dimerized fatty acid-based diols such as Pripol 2033 (C36 aliphatic diol); triols such as glycerol, trimethylolpropane, trimethylolethane and 1,3,5-tris(2-hydroxyethyl)isocyanurate; tetraols such as pentaerythritol and di-trimethylolpropane; and hexaols such as dipentaerythritol; polyacids such as oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, adipic acid, citric acid, propane-1,2,3-tricarboxylic acid, trimesic acid and the corresponding thioacids, isocyanates and thiocyanate counterparts. Other examples of suitable scaffolds include alkyl carbonate or chloroformate derivatives of polyols such as ethylene glycol, propylene glycol, glycerol, cyclohexanedimethanol or pentaerythritol.

[0072] In one embodiment, n is 0, m is 1, X is -C(O)- and R 1 It is C1-C 12 In another embodiment, n is 0, m is 0 and R 1 It is C1-C 12 Alkyl groups, such as methyl.

[0073] The monomer mixture can have any suitable furanone moiety / vinyl moiety molar ratio. In one embodiment, the molar ratio of furanone moiety / vinyl moiety can be in the range of 1:10-10:1, especially 1:5-5:1, such as 1:3-3:1, 1:2-2:1 or even 1:1.5-1.5:1.

[0074] In one embodiment, the weight fraction of the monomer comprising at least two vinyl groups in the composition is at most 5 weight percent.

[0075] In one embodiment, the radiation curable coating composition does not contain compounds having two or more acryloyl or methacryloyl groups. The presence of such compounds may have an adverse effect on film formation.

[0076] The total amount of butenolide monomer A and vinyl monomer B in the radiation curable coating composition may be in the range of 70-100 wt%, more preferably 80-100 wt%, even more preferably 90-100 wt%.

[0077] The coating composition is radiation curable. The coating composition can be cured by photoinitiation, i.e. by irradiation with visible light or UV light. In one embodiment, the composition further comprises c) a photoinitiator.

[0078] The photoinitiator can be a photoinitiator or a mixture of two or more thereof. The photoinitiator generates free radicals when exposed to radiant energy within the visible or UV wavelength range. Depending on the wavelength, any suitable photoinitiator known in the art can be used. Suitable photoinitiators include benzoin derivatives, benzil ketals, α-hydroxyalkyl phenones, monoacylphosphine oxides (MAPO) and bisacylphosphine oxides (BAPO), such as diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, 1-hydroxycyclohexyl phenyl ketone, di(2,4,6-trimethylbenzoyl)phenyl phosphine oxide, di(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinylpropan-1-one, methyl phenylglyoxylate. Mixtures of these compounds can also be used.

[0079] The photoinitiator can be present in an amount of 0.1 to 10 wt %, eg, 0.5 to 5.0 wt %, based on the total weight of the coating composition.

[0080] Alternatively, curing of the radiation curable coating composition may be initiated by electron beam or gamma radiation.For initiation by electron beam or gamma radiation, no photoinitiator is required.

[0081] The radiation curable coating composition can be a powder coating composition or a liquid coating composition, preferably a liquid coating composition. The radiation curable coating composition is preferably a substantially solvent-free liquid coating composition. As referred to herein, a substantially solvent-free coating composition is a coating composition comprising at most 1 wt %, more preferably at most 0.5 wt %, and still more preferably 0 wt % of an organic solvent.

[0082] In the event that the viscosity of the butenolide monomer A and the vinyl monomer B is undesirably high, the coating composition may contain some organic solvent to control the viscosity. Preferably, the coating composition contains at most 30 wt %, more preferably at most 20 wt %, even more preferably at most 10 wt %, still more preferably at most 5 wt % or at most 2 wt % organic solvent.

[0083] Suitable organic solvents are solvents in which the butenolide monomer A and the vinyl monomer B and the cured polymer dissolve under polymerization conditions. The organic solvent may be an oxygen-containing organic solvent, such as an alcohol, ketone, ester or ether. The solvent is especially a glycol ether, glycol ester or alkyl acetate, such as 1-methoxy-2-propanol or butyl acetate.

[0084] The radiation-curable coating composition is not an aqueous coating composition, i.e., water is not the liquid medium in which the butenolide monomer A and the N-vinyl monomer B are dissolved or dispersed. The radiation-curable coating composition may contain a small amount of water, such as water contained in additives included in the coating composition. In one embodiment, the radiation-curable coating composition contains less than 5% by weight, more preferably less than 1% by weight, of water.

[0085] The radiation curable coating composition may contain other ingredients commonly used in coating compositions, such as color pigments, extender pigments and one or more additives, such as light stabilizers, other stabilizers, defoamers, matting agents, wetting agents or flow agents.

[0086] Radiation Curing The radiation-curable coating composition can be formed by exposing the coating composition to visible light or UV radiation, electron beam radiation, or gamma radiation to form a cured coating.

[0087] The radiation-curable coating composition can be applied to the substrate by conventional techniques including spraying, rolling, blade coating, pouring, brushing or dipping. After evaporation of any organic solvent and / or water (if present), the coating composition produces a non-sticky, dry to very sticky coating. Curing is then initiated by radiation. Any suitable radiation source can be used. Radiation curing can especially be by electron beam radiation, UV radiation or visible light radiation.

[0088] In one embodiment, the radiation-curable coating composition further comprises c) a photoinitiator and the radiation-curable coating composition is cured by exposing the coating composition to visible light or UV radiation, for example visible light having a wavelength in the range of 400-600 nm or UV radiation having a wavelength in the range of 200-400 nm, in particular UV radiation having a wavelength in the range of 280-400 nm or preferably 320-400 nm (UV-A radiation).

[0089] For UV radiation, for example, mercury lamps, metal halide lamps, xenon lamps or UV-LED lamps can be used. Preferably, UV-LED lamps are used.

[0090] The radiation curing of the radiation curable coating composition can be carried out under ambient conditions, such as room temperature and atmospheric pressure. Room temperature as referred to herein is a temperature in the range of 15-30° C. Curing can be accelerated by post-heating, for example, to a temperature in the range of 40-100° C., preferably 50-80° C.

[0091] In one aspect, the present invention relates to a substrate coated with a coating deposited from a radiation-curable coating composition. For example, the coated substrate can be obtained by a method comprising the following steps:

[0092] - providing a substrate,

[0093] - applying the radiation curable coating composition as defined herein to a substrate; and

[0094] - Radiation curing the coating composition to form a cured coating.

[0095] The substrate may be any suitable substrate, such as wood, polymer, composite, metal or mineral substrate.The substrate may be a primed or bare substrate.

[0096] In one embodiment, the monomer mixture may contain other ethylenically unsaturated monomers other than the butenolide monomer A and the N-vinyl monomer B that can be copolymerized by free radical polymerization. Examples of such other monomers are acrylic acid, methacrylic acid, alkyl (meth)acrylates, styrene, methylene malonate, itaconic acid, vinyl acetate, divinyl ethers such as ethylene glycol divinyl, diethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,4-butanediol divinyl ether, and trivinyl ethers such as trimethylolpropane trivinyl ether. The presence of divinyl ether in the monomer mixture provides a base polymer having crosslinking functional groups.

[0097] In one embodiment, the monomer mixture comprises less than 50 mol%, e.g., less than 30 mol%, less than 20 mol%, or less than 10 mol% of other ethylenically unsaturated monomers. In one embodiment, the monomer mixture comprises other ethylenically unsaturated monomers in the range of 1-50 mol%, e.g., 2-30 mol%, or 5-20 mol%. In another embodiment, the monomer mixture contains no other ethylenically unsaturated monomers.

[0098] Copolymerization is a free radical polymerization process. Conditions that allow monomers to copolymerize to form addition polymers via free radical polymerization are well known in the art. Suitable conditions generally include the presence of an initiator.

[0099] Copolymerization can be carried out in an organic solvent (solvent polymerization). In solvent polymerization, the monomer mixture is dissolved in a suitable organic solvent, heated to the desired reaction temperature and a suitable initiator is added in an appropriate amount. The temperature during solvent polymerization is generally in the range of 50-180°C, for example, 70-160°C. It should be understood that the optimal polymerization temperature depends on the decomposition temperature of the initiator used and the boiling point of the monomer under the pressure under which the polymerization is carried out. During the copolymerization, the monomer mixture can be dissolved in any suitable solvent. A suitable organic solvent is a solvent in which all monomers in the monomer mixture and the resulting copolymer are dissolved under polymerization conditions. In one embodiment, the organic solvent is an oxygen-containing organic solvent, such as an alcohol, glycol ether, glycol ester, alkyl acetate, ketone, ester or glycol ether / ester. For example, the solvent can be a glycol ether or alkyl acetate. In another embodiment, the solvent is N-methylpyrrolidone (NMP).

[0100] Alternatively, the copolymerization can be carried out as an emulsion polymerization process, wherein the monomers are emulsified in an aqueous phase and subsequently copolymerized.The emulsion polymerization can be carried out at a temperature in the range of 15-90°C.

[0101] Any suitable initiator may be used. Suitable initiators are known in the art and include organic peroxides and azo initiators. Examples of azo initiators include azobisisobutyronitrile (AIBN) and 2,2'-azobis(2-methylbutyronitrile) (AMBN).

[0102] Examples of suitable organic peroxides include tert-butyl peroxy-3,5,5-trimethylhexanoate, benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, acetyl peroxide, tert-butyl peroxy-2-ethylhexyl carbonate, tert-butyl peroxyoctanoate, tert-amyl peroxyoctanoate, and tert-butyl peroxybenzoate. The initiator may be added in any suitable amount, typically up to 6 mol%, for example, in the range of 1-4 mol%, based on the total moles of the ethylenically unsaturated monomers. The entire amount of initiator may be added in two or three steps, i.e., a first amount is added at the beginning of the polymerization and additional amounts are added during the polymerization reaction.

[0103] Optionally, a chain transfer agent is used during the polymerization process. Any suitable chain transfer agent can be used in a suitable amount. Suitable chain transfer agents are known in the art and include methyl mercaptopropionate, 1-dodecanethiol, 1-octanethiol, thioglycolic acid, 2-hydroxy-1-ethanethiol and butenediol.

[0104] The copolymerization can be carried out batchwise, ie by charging all monomers and initiator at the beginning of the polymerization, or by gradually charging parts of the monomers and / or initiator during the copolymerization, ie under so-called starvation feeding conditions.

[0105] The copolymers thus obtained have been found to have properties that make them suitable for use as binder polymers in coating compositions. The binder polymers have a relatively high content of butenolide, a component obtainable from renewable raw materials. In particular, binder polymers having glass transition temperatures in the range of +67°C to +88°C, as measured by differential scanning calorimetry (DSC) according to ISO 11357-2 using a heating rate of 20 K / min, can be obtained. Another advantageous property of the binder polymer is that it has a polymer backbone with functional groups (at the butenolide monomers) that can be used for crosslinking.

[0106] The coating composition may be a solventborne or waterborne liquid coating composition, or a powder coating composition, such as a liquid coating composition, more particularly a waterborne liquid coating composition in which the binder polymer is emulsified in an aqueous liquid water phase.

[0107] The coating composition may contain other ingredients commonly used in coating compositions, such as color pigments, extender pigments, coalescing solvents, and one or more additives, such as surfactants, defoamers, thickeners, leveling agents, and biocides.

[0108] One aspect of the present invention relates to a substrate coated with a coating deposited from a coating composition. The substrate can be any suitable substrate, such as wood, a polymer, a composite material, a metal, or a mineral substrate. The substrate can be primed or bare.

[0109] The coating composition or radiation curable coating composition can be used as a single layer applied directly to a substrate or in a multilayer system, for example, as a primer layer, basecoat, clearcoat or topcoat layer. The coating composition can be used in a variety of applications, such as coating wood, electronic equipment, plastic automotive components, food cans, or as an architectural coating.

[0110] The present invention is further illustrated by means of the following non-limiting examples. Example

[0111] Measurement technology

[0112] Monomer conversion and initial reaction rate

[0113] Method 1 (monomer conversion, initial reaction rate by NMR):

[0114] 40 μL of sample was diluted with CDCl3 (550-600 μL) in NMR tube for reference. 20-40 μL of sample was taken from the reaction mixture with a microsyringe at different time points and diluted with CDCl3 (550-600 μL) in NMR tube. All samples were washed with water. 1H NMR was analyzed on a 400 MHz spectrometer (typically D1 = 5, ns = 8). After processing the spectra for phase and baseline correction, integration of the relevant peaks (one for each monomer) allowed monitoring of conversion. Initial reaction rates were calculated from sampling over time according to the method described in Hermens et al., Sci. Adv. 2020; 6:eabe0026.

[0115] Method 2 (monomer conversion by solids content measurement):

[0116] The solids content of the polymer solution was determined in accordance with ISO 3251 with an initial sample mass of 1.0 g, a test duration of 60 minutes, and a temperature of 125° C. The monomer conversion was calculated based on the measured solids content. Residual monomer evaporated under the test conditions, while any polymer formed did not.

[0117] The number average molecular weight (Mn) and weight average molecular weight (Mw) were determined by GPC.

[0118] Number and weight average molecular weights were determined using gel permeation chromatography (GPC) with tetrahydrofuran (THF) (+1% acetic acid) as eluent (1 ml / min) on a styrene-divinylbenzene column calibrated with polystyrene standards.

[0119] The polydispersity index (PDI) was calculated by dividing the measured Mw by the measured Mn.

[0120] Glass transition temperature (Tg)

[0121] Tg was measured by differential scanning calorimetry (DSC) using a TA Instruments DSC Q2000 equipment in the modulated mode according to ASTM D3418.

[0122] A DSC cup filled with 6+ / -1 mg of sample and an empty DSC reference cup were heated in a differential scanning calorimeter (DSC) in a modulated manner (+ / -1°C every 40 seconds) at 5°C / min from -80°C to 110°C in two consecutive operations using helium (50 ml / min) as a purge gas. Fourier transformation enables the separation of the modulated heat flow into a heat capacity component (reversing heat flow) and a kinetic component (irreversing heat flow), which allows the separation of different thermal events occurring simultaneously.

[0123] The heat capacity of the material changes rapidly below its Tg (observed in the reversing heat flow curve), resulting in a significant drop in the reversing heat flow curve within a certain transport region. Tg is calculated at the inflection point (Tg(I)) for both operations.

[0124] The following vinyl monomers were used:

[0125] - Vinyl neodecanoate (available from Hexion) VeoVa 10

[0126] - Vinyl neononanoate (available from Hexion) VeoVa 9

[0127] -N-vinylpyrrolidone

[0128] -N-vinylcaprolactam

[0129] -N-vinylimidazole

[0130] Use the following R 1 Butenoic acid lactone monomer of group:

[0131] -C(O)CH3(5-acetoxy-2(5H)furanone or "acetoxybutenolide")

[0132] -CH3(5-methoxy-2(5H)-furanone or "methoxybutenolide")

[0133] The following solvents and reagents were used:

[0134]

[0135] The following initiators were used:

[0136] -tert-Butyl peroxy-3,5,5-trimethylhexanoate T42S

[0137] Preparation Examples 1 and 2

[0138] Preparation Example 1

[0139] Acetoxybutenoic acid lactone 5-oxo-2,5-dihydrofuran-2-yl acetate

[0140] Chemical formula: C6H5O4

[0141] Molecular weight: 142.1100

[0142] This product and its synthesis have been previously described in GC Resende, ES Alvarenga, JCG Galindo, FA Macias, J. Braz. Chem. Soc. 2012, 23 (12), 2266-2270. Hydroxybutenoic acid lactone (1 equivalent, 500 mg, 5.00 mmol, gray solid) was dissolved in anhydrous DCM (25 mL) in a flask under N2 atmosphere and cooled to 0°C with an ice bath. Acetic anhydride (1.6 equivalents, 754 μL, 7.99 mmol) was added, followed by a solution of DMAP (0.3 equivalents, 183 mg, 1.50 mmol) in anhydrous DCM (1.5 mL). The mixture was stirred at 0°C for 1 hour and then allowed to warm to room temperature. TLC (25% AcOEt / hexane, KMnO4 color development) showed the formation of a new product at Rf=0.37. The clear solution was washed with water (25 mL). In 40mL 4-nitro-2-oxo-4-oxo ...

[0143] Preparation Example 2

[0144] butenolide

[0145] 5-Methoxy-2(5H)-furanone

[0146] Chemical formula: C5H5O3

[0147] Molecular weight: 114.1000

[0148] This product and its synthesis were previously described in Hermens et al., Sci. Adv. 2020; 6:eabe0026. 5-Hydroxy-2(5H)-furanone (100.0 g, 1 mol) was dissolved in 500 mL of anhydrous methanol and heated under reflux for 20 hours. 1 The conversion was followed by H NMR until all 5-hydroxy-2(5H)-furanone was consumed. The solvent was evaporated under reduced pressure and the crude product was heated under reduced pressure (70°C, 1.0×10 -2 The mixture was distilled at 400 mbar to give 5-methoxy-2(5H)-furanone (86.5 g, 0.76 mol, 76%) as a light yellow oil.

[0149] Examples 1-9

[0150] To a screw-cap 4-vial equipped with a 10 mm stir bar and septum was added one of Preparation Example 1 or 2 and N-vinyl monomer (2 mmol total), internal standard (typically 1,3,5-trimethoxybenzene, 1 mmol) and solvent (N-methylpyrrolidone, 500 μL, [monomer] = 4 M).

[0151] The mixture is homogenized, briefly heated if necessary (e.g. in the case of insoluble monomers), and then a 40 μL sample is diluted with CDCl 3 (550-600 μL) in an NMR tube for reference. The vial is then sealed and preheated at 120° C. for 1-2 minutes. Trigonox 42S (60 μmol, 3 mol % relative to the monomer) is added to the hot mixture via a microsyringe through a septum, corresponding to t=0. At different time points, 20-40 μL samples are taken from the reaction mixture using a microsyringe and diluted with CDCl 3 (550-600 μL) in an NMR tube.

[0152] Monomer conversion and initial reaction rate were calculated according to Method 1 as described above.

[0153] Table 1

[0154]

[0155] The results show that high initial reaction rates and high conversions can be achieved when N-vinylamide is used as a comonomer. In addition, the identity and molar ratio of the comonomers affect the initial reaction rate and conversion.

[0156] Examples 10 and 11 and Comparative Examples 1 and 2

[0157] The base polymer is prepared by adding butenolide monomer and Dowanol PM into a three-necked round-bottom flask equipped with a reflux condenser. The mixture is heated to a temperature of 125°C and under reflux conditions, under nitrogen protection, while maintaining the temperature at 125°C, the vinyl monomer and tert-butyl peroxide-3,5,5-trimethylhexanoate (Trigonox42S, purchased from Nouryon) in another Dowanol PM are added within 2 hours. Then some initiator is added and the reaction is continued for 1 hour; then another initiator is added and the reaction is continued for another 1 hour. The reaction mixture is cooled to room temperature. The calculated solid content (based on the total weight of monomer, initiator and solvent, the weight of monomer and initiator) is 43% by weight. The molar ratio of butenolide monomer to vinyl monomer is 1:1 in each case.

[0158] A 200 μm wet film of each of Comparative Examples 1 and 2 and Examples 10 and 11 was drawn down on a glass plate using a drawdown bar. After drying for 7 days at 23° C. and 50% relative humidity, the pendulum hardness (Persoz hardness) was determined according to ISO 1522A. The time required for the pendulum's amplitude to decrease from 12 degrees to 4 degrees was measured.

[0159] The measured properties (monomer conversion, Tg, molecular weight distribution, Persoz hardness) of the different base polymers prepared are shown in Table 2. The monomer conversion was measured according to Method 2 as described above.

[0160] Table 2

[0161]

[0162] *No film formation occurred - Persoz hardness not tested

[0163] These examples show that using NVP as a comonomer provides an increased Tg in the case of acetoxybutenolide monomer without affecting the molecular weight distribution when the same synthesis procedure is used. In the case of methoxybutenolide, polymer conversion and coating hardness are shown to increase when NVP is used as a comonomer.

Claims

1. A radiation-curable coating composition comprising a monomer mixture comprising: a) at least one butenolide monomer A, which is a substituted 5-hydroxy-2(5H)-furanone of the general formula (I): in: n is 0 or an integer from 1 to 5; m is 0 or 1; R 1 is an alkyl group or an aryl group; X is -C(O)-, -C(O)O-, -C(O)NR 2 -, -S(O)-, -S(O2)-, -C(O)S-, -C(S)S- and -C(S)NR 2 - any one of; wherein R 2 is hydrogen, alkyl or aryl; Or when n is 0, R 1 and R 2 together with the nitrogen atom through which they are attached, form a nitrogen-containing heterocyclic group or a nitrogen-containing heteroaryl group; and b) at least one N-vinyl monomer B, which is a compound of the general formula (II): where R 4 and R 5 are each independently any one of hydrogen, alkyl, aryl, heteroalkyl or heteroaryl and Y is selected from O, NR 6 and S; where R 6 is hydrogen, alkyl, aryl, heteroalkyl or heteroaryl; wherein R 4 、R 5 and R 6 Any two of the group consisting of the group consisting of: a) a and b) b are taken together with the atom through which they are attached to form a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl group; and wherein i) a is 1 and b is 1; or ii) a is 0 and b is 2; and wherein at least one monomer of A and B comprises at least two vinyl groups; and wherein the coating composition does not contain a compound having two or more acryloyl or methacryloyl groups.

2. The radiation-curable coating composition according to claim 1, wherein the weight fraction of the monomer comprising at least two vinyl groups in the composition is at most 5% by weight.

3. The radiation curable coating composition according to claim 1 or 2, wherein the composition further comprises c) a photoinitiator.

4. The radiation curable coating composition according to any one of claims 1 to 3, wherein in the general formula (II) a is 1, b is 1, R 4 and R 5 Together with the atoms through which they are attached, they form a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl group and Y is O.

5. The radiation curable coating composition according to any one of claims 1 to 4, wherein the N-vinyl monomer B is N-vinylpyrrolidone or N-vinylcaprolactam.

6. The radiation curable coating composition according to any one of claims 1 to 3, wherein a is 1, b is 1, Y is NR 6 And R 4 and R 6 Together with the atoms through which they are attached, they form a nitrogen-containing cyclic heteroalkyl group or a nitrogen-containing heteroaryl group.

7. The radiation-curable coating composition according to claim 6, wherein the N-vinyl monomer B is N-vinylimidazole.

8. The radiation curable coating composition according to any one of claims 1 to 3, wherein a is 0, b is 2, Y is O and R 5 Each, together with the atom through which they are attached, forms a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl group.

9. The radiation-curable coating composition according to claim 8, wherein the N-vinyl monomer B is N-vinylphthalimide.

10. The radiation curable coating composition according to any one of claims 1 to 9, wherein n is 0.

11. The radiation curable coating composition according to any one of claims 1 to 10, wherein X is -C(O)-, -C(O)O- or -C(O)NR 2 -.

12. The radiation curable coating composition according to any one of claims 1 to 11, wherein R 1 It is phenyl, C1-C 20 Alkyl or C5-C7 cycloalkyl.

13. The radiation curable coating composition according to any one of claims 1 to 12, wherein the molar ratio of furanone moieties to vinyl moieties is in the range of 1.5:1.0 to 1.0:1.

5.

14. A monomer mixture comprising: a) at least one butenolide monomer A, which is a substituted 5-hydroxy-2(5H)-furanone of the general formula (I): in n is 0 or an integer from 1 to 5; When n is 0, m is 1 and when n is an integer from 1 to 5, m is 0 or 1; R 1 is an alkyl group or an aryl group; X is -C(O)-, -C(O)O-, -C(O)NR 2 -, -S(O)-, -S(O2)-, -C(O)S-, -C(S)S- and -C(S)NR 2 -Any one of; wherein R 2 is hydrogen, alkyl or aryl; Or when n is 0, R 1 and R 2 together with the nitrogen atom through which they are attached, form a nitrogen-containing heterocyclic group or a nitrogen-containing heteroaryl group; and b) at least one N-vinyl monomer B, which is a compound of the general formula (II): where R 4 and R 5 are each independently any one of hydrogen, alkyl, aryl, heteroalkyl or heteroaryl and Y is selected from O, NR 6 and S; where R 6 is hydrogen, alkyl, aryl, heteroalkyl or heteroaryl; wherein R 4 、R 5 and R 6 Any two of the following, taken together with the atom through which they are attached, form a nitrogen-containing cyclic heteroalkyl or nitrogen-containing heteroaryl; and wherein i) a is 1 and b is 1; or ii) a is 0 and b is 2.

15. A base polymer obtainable by copolymerizing a monomer mixture as defined in claim 14.

16. A coating composition comprising a binder polymer as defined in claim 15.

17. A substrate coated with a coating deposited from a radiation curable coating composition as defined in any one of claims 1 to 13 or from a coating composition as defined in claim 16.

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