Acrylic copolymer with little yellowing after photo-curing

Abstract

Overlapped high T g Monomer units and / or overlapped low T g There is provided an acrylic copolymer comprising monomer units; polymerized chromophore monomer units containing a chromophore moiety selected from thioxanthone, anthraquinone, or camphorquinone; and optionally polymerized additional monomer units. There is also provided a product obtained by photocuring a composition containing the acrylic copolymer, the cured composition having little yellowing. There is also provided a method for coating a substrate, which comprises applying a composition containing the acrylic copolymer to the substrate and exposing the coating to UV radiation to cure the composition.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to acrylic copolymers, and more specifically to acrylic copolymers containing pendant photoinitiators with low yellowing after photocuring.

Background Art

[0002] Radiation curable compositions are used in a variety of applications, from industrial coatings and graphic arts to ultraviolet curable nail gels and 3D printing. Small molecule photoinitiators are important components in such compositions because they can promote polymerization when exposed to an appropriate light source.

[0003] The choice of small molecule photoinitiator in a radiation curable composition affects the light source required to initiate polymerization and the properties of the photocured polymer. For example, small molecule photoinitiators that promote polymerization when exposed to short wavelength light tend not to yellow, have good surface curing but insufficient cure depth. In contrast, small molecule photoinitiators that promote polymerization when exposed to long wavelength light have strong yellowing, good cure depth but insufficient surface curing and the surface may become sticky.

[0004] Small molecule photoinitiators can be further classified as Norrish type I or Norrish type II. Norrish type I photoinitiators cleave when exposed to an appropriate light source to form two radical species that induce crosslinking. Norrish type II photoinitiators generate an excited state when exposed to an appropriate light source and abstract hydrogen from a co-initiator to generate a radical that induces crosslinking.

[0005] Commonly used Norrish type II photoinitiators include benzophenone, thioxanthone, camphorquinone, and anthraquinone. These photoinitiators typically form a pair with co-initiators such as amines, alcohols, and ethers. Tertiary amines are most commonly used as co-initiators because of their high reactivity towards the excited state Norrish type II photoinitiators.

[0006] Norrish type II photoinitiators (i.e., thioxanthones) having an absorption band at longer wavelengths can be particularly effective photoinitiators for certain applications. In particular, additives in some radiation curable compositions can absorb light at shorter wavelengths, thus inhibiting a photoinitiator that absorbs light at a similar wavelength from properly initiating polymerization, which can lead to improper curing. Since the additives may not absorb light at longer wavelengths, using a Norrish type II photoinitiator (i.e., thioxanthone) having an absorption band at a longer wavelength may reduce the inhibitory effect. SUMMARY OF THE INVENTION

[0007] Although thioxanthones and other Norrish type II photoinitiators having an absorption band at longer wavelengths are useful, they are not without drawbacks. In particular, they tend to cause yellowing in crosslinked polymers and do not photobleach over time. Furthermore, they can be difficult to remove from crosslinked polymers and instead may remain within the polymer matrix and slowly diffuse to the surface over time. Such migration of photoinitiators can be harmful depending on the application. Accordingly, there is a need for Norrish type II photoinitiators having an absorption band at longer wavelengths that result in crosslinked polymers with less initial yellowing and exhibit little or no migration after curing.

[0008] Embodiments of the acrylic copolymers disclosed herein meet this need by incorporating pendant type Norrish type II photoinitiators having an absorption band at longer wavelengths attached to the oligomeric backbone. When the acrylic copolymer is mixed with at least one (meth)acrylate monomer and the resulting composition is photocured, the resulting polymer may have less yellowing. Furthermore, since the acrylic copolymer is incorporated into the polymer framework during photocuring, the photoinitiator moiety may exhibit little or no migration.

[0009] In one or more embodiments, an acrylic copolymer is provided. The acrylic copolymer has a glass transition temperature (T g) having a high T g monomer, T below 25 °C g having a low T g monomer, or a high T having a glass transition temperature (T g ) g monomer and a low T g having g a combination of monomers, (2) a chromophore monomer containing a moiety selected from thioxanthone, anthraquinone, or camphorquinone, and (3) a reaction product of an optional at least one additional monomer.

[0010] In some embodiments, a curable composition is provided. The curable composition comprises the acrylic copolymer of the present invention and a reactive diluent.

[0011] In some embodiments, a method of preparing a curable composition is provided. The method comprises the following steps: - a step of preparing by dissolving the acrylic copolymer according to the present invention in a non-reactive solvent; - a step of adding a reactive diluent to obtain a diluted curable composition; - a step of removing at least a part of the non-reactive solvent from the diluted curable composition to obtain a curable composition is included.

[0012] In some embodiments, a method of curing a curable composition is provided. The method comprises curing the curable composition by irradiating the curable composition with a light source having a wavelength and / or intensity capable of activating the polymerized chromophore monomer units of the acrylic copolymer and causing crosslinking of the acrylic copolymer and / or the reactive diluent.

[0013] In some embodiments, a cured composition is provided. The cured composition is a product obtained by photocuring a composition comprising an acrylic copolymer and a reactive diluent, preferably at least one (meth)acrylate monomer. The cured composition has an initial color of 0.1 to 50 APHA-10 mm; an initial yellowness of 0.01 to 2 (b * ); and a T above 0 °Cg is shown.

[0014] In one or more embodiments, a method of coating a substrate is provided. The method includes applying a composition to the substrate to form an uncured coating of the composition on the substrate. The composition includes an acrylic copolymer and a reactive diluent, preferably at least one (meth)acrylate monomer. The method further includes exposing the uncured coating to ultraviolet light to cure the composition and obtain a cured coating on the substrate.

[0015] Additional features and advantages of the described embodiments are described in the following detailed description and will be readily apparent to those skilled in the art in part from that description, or may be recognized by practicing the described embodiments including the following detailed description, the claims, and the accompanying drawings. Modes for Carrying Out the Invention

[0016] [Definitions] As used herein, the term "comprises a" may mean "comprises one or more".

[0017] Unless otherwise specified, weight percentages in a compound or composition are expressed relative to the respective weights of the compound or composition.

[0018] As used herein, the term "substituted" means that at least one hydrogen atom (-H) bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group is replaced by a substituent (e.g., R S ). The term "over-substituted" means that every hydrogen atom (H) bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group is replaced by a substituent (e.g., R S ). The term "multi-substituted" means that at least two (but not all) hydrogen atoms bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group are replaced by substituents. Unless otherwise defined or limited in a particular context, substituents in general, or R SThe substituent referred to as may be any chemical moiety and can typically be a chemical moiety having from 1 to 50, or from 1 to 40, or from 1 to 30, or from 1 to 20, or from 1 to 10 total atoms, but is not necessarily limited thereto. Substituent R S Examples of include, but are not limited to, hydrocarbyl, heterohydrocarbyl, aryl, heteroaryl, alkyl, cycloalkyl, heteroatom, carbonyl, hydroxy, ester, ether, amine, amide, or halide according to each definition herein or its generally understood meaning, and any of these substituents may be either substituted or unsubstituted themselves. In some embodiments, substituent R S is selected from (C1-C 30 ) hydrocarbyl, (C1-C 30 ) heterohydrocarbyl, (C6-C 30 ) aryl, or (C6-C 30 ) heteroaryl.

[0019] The term "hydrocarbyl" means a monovalent hydrocarbon in which each hydrocarbon is aromatic or non-aromatic, saturated or unsaturated, straight-chain or branched-chain, cyclic (having three or more carbons, including monocyclic and polycyclic, fused and non-fused polycyclic, and bicyclic) or acyclic, and is either substituted by one or more R S or is unsubstituted. In this disclosure, hydrocarbyl can be unsubstituted or substituted alkyl, unsubstituted or substituted cycloalkyl, or unsubstituted or substituted aryl. Hydrocarbyl may not contain any heteroatoms selected from O, N or S. (C1-C 30 ) hydrocarbyl is a hydrocarbyl having from 1 to 30 carbon atoms.

[0020] The term "heterohydrocarbyl" means a hydrocarbyl having one or more heteroatoms independently selected from O, N, or S. (C1-C 30 ) heterohydrocarbyl is a heterohydrocarbyl having from 1 to 30 carbon atoms.

[0021] The term "aryl" means an optionally substituted polyunsaturated aromatic group. Aryl can be monocyclic (i.e., phenyl) or can contain more than one ring where at least one ring is aromatic. When aryl contains more than one ring, the rings can be fused together via covalent bonds (e.g., biphenyl). The aromatic ring can optionally contain one or two additional fused rings (i.e., cycloalkyl, heterocycloalkyl, or heteroaryl). Examples include phenyl, naphthyl, biphenyl, phenanthrenyl, and naphthacenyl.

[0022] The term "alkyl" means a monovalent saturated acyclic hydrocarbon group of the formula -C n H 2n+1 (where n is from 1 to 20). Alkyl can be straight-chain or branched. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, 2-methylbutyl, 2,2-dimethylpropyl, n-hexyl, 2-methylpentyl, 2,2-dimethylbutyl, n-heptyl, 2-ethylhexyl, and the like.

[0023] The term "cycloalkyl" means a monovalent saturated cycloaliphatic hydrocarbon group containing a ring. Examples of cycloalkyl groups include cyclopentyl, cyclohexyl, and isobornyl, any of which can be substituted or unsubstituted.

[0024] The term "heterocycloalkyl" means a cycloalkyl having at least one ring atom that is a heteroatom selected from O, N, or S.

[0025] The term "halogen" means an atom selected from Cl, Br, F, and I.

[0026] The term "alkoxy" means a group of the formula -O-alkyl, where alkyl is as defined above.

[0027] The term "aryloxy" means a group of the formula -O-aryl, where aryl is as defined above.

[0028] The term "thioalkyl" means a group of the formula -S-alkyl, where alkyl is as defined above.

[0029] The term "thioaryl" means a group of the formula -S-aryl, where aryl is as defined above.

[0030] The term "alkenyl" means a monovalent acyclic hydrocarbon group containing at least one C=C double bond. The alkenyl may be linear or branched.

[0031] The term "alkynyl" means a monovalent acyclic hydrocarbon group containing at least one C≡C triple bond. The alkynyl may be linear or branched.

[0032] The term "aralkyl" means an aryl substituted with an alkyl group. An example of an aralkyl group is tolyl.

[0033] The term "alkaryl" means an alkyl substituted with an aryl group. An example of an alkaryl group is benzyl (-CH2-phenyl).

[0034] The term "heteroaryl" means an aryl having at least one ring atom that is a heteroatom.

[0035] The term "alkylamino" means an alkyl substituted with at least one amino group.

[0036] The term "alkylthiol" means an alkyl substituted with at least one thiol group.

[0037] The term "hydroxyalkyl" means an alkyl substituted with at least one hydroxy group.

[0038] The term "haloalkyl" means an alkyl substituted with at least one halogen.

[0039] The term "alkylene" or "alkanediyl" means a linker derived by removing one hydrogen atom from each point of attachment of the linker from an alkane of the formula C m H 2m+2 An alkylene can be divalent, trivalent, tetravalent, or can have a higher valence.

[0040] The term "alkoxylation" means a compound, group or linker containing one or more oxyalkylene moieties, in particular oxyethylene (-O-CH2-CH2-), oxypropylene (-O-CH2-CH(CH3)- or -O-CH(CH3)-CH2-), oxybutylene (-O-CH2-CH2-CH2-CH2-), and mixtures thereof. For example, an alkoxylated compound, group or linker can contain from 1 to 30 oxyalkylene moieties.

[0041] The term "(meth)acrylate" means acrylate or methacrylate. The term "acrylate" means an acryloyloxy group (-O-C(=O)-CH=CH2). The term "methacrylate" means a methacryloyloxy group (-O-C(=O)-C(CH3)=CH2).

[0042] The term "(meth)acrylate monomer" means a monomer having a (meth)acrylate group.

[0043] As used herein, a "monomer" has a number average molecular weight of less than 1000 g / mol, preferably from 100 to 950 g / mol.

[0044] As used herein, an "oligomer" has a number average molecular weight of 1000 g / mol or more, preferably from 1050 to 60000 g / mol, more preferably from 10000 to 50000 g / mol.

[0045] The term "glass transition temperature" or "T g " refers to the temperature at which a material changes from a glassy state to a rubbery state. In this context, the term "glassy" means that the material is hard and brittle, and the term "rubbery" means that the material is elastic and flexible. In the case of a polymeric material, T g is the critical temperature that separates glassy behavior from rubbery behavior. When a polymeric material is at a temperature below its T g , the material is essentially frozen, and large-scale molecular motion is significantly restricted. On the other hand, when a polymeric material is at a temperature above its T g , molecular motion occurs on the scale of its repeating units, and it becomes flexible or rubbery.

[0046] All references herein to the T g of a monomer refer to the T g of the homopolymer formed from that monomer. The T g values of common monomers are well known from the literature. If not reported in the literature, the glass transition temperature value can be determined as the inflection temperature (T i ) in accordance with ASTM E1356-08, "Standard Test Method for Assignment of the Glass Transition Temperature by Differential Scanning Calorimetry". The glass transition temperature of the acrylic copolymers described herein and referred to in the following examples is calculated using the Fox equation based on the mass fraction and T g values of each individual monomer of the polymeric material containing oligomers or multiple different types of monomers.

[0047] The terms "mass fraction" and "weight fraction" are used interchangeably herein and are considered equivalent to each other with respect to the embodiments or examples herein.

[0048] The "Fox equation" refers to Equation (1): TIFF2025523936000001.tif10170Here, T g,mixis the glass transition temperature of a mixture of i chemically distinct components, such as two or more separate monomers of an oligomer or polymer, and T g,i is the glass transition temperature of the i-th component, and ω i is the mass fraction of the i-th component based on the total mass of the oligomer or polymer. Hereinafter, the value of T g,mix for a plurality of separate monomers in an oligomer or polymer is referred to as the "Fox equation average T g ".

[0049] In the case of two components A and B, the Fox equation is simplified to equation (2): TIFF2025523936000002.tif11170

[0050] The term "high T g monomer unit" refers to a monomer that, when homopolymerized, produces a homopolymer having a T g of 25 °C or higher. In an embodiment of an oligomer in which only one type of high T g monomer unit is present, the T g of the high T g monomer unit is the T g of the homopolymer of one type of high T g monomer unit. In an embodiment of an oligomer in which two or more distinct high T g monomer units are present, the T g of the high T g monomer units of the oligomer is such that, in equation (1), the individual mass fractions ω i are not based on the total mass of the entire oligomer, but rather on the total mass of all high T g monomer units (i.e., monomer units having a T g of 25 °C or higher) present in the oligomer, and is the mass fraction of each individual high T g monomer unit in the oligomer. The Fox equation average T g of the combination of high T g monomer units is collectively referred to.

[0051] The term "Fox average" may also be used herein with respect to a single monomer that is not part of a mixture of two or more monomers. The Fox average T for a single monomer g is equal to the T of the single monomer itself as defined herein, since the mass fraction term ω in such a situation is equal to 1. g It should be readily understood to be equal.

[0052] The term "low T g monomer unit" refers to a monomer that, when homopolymerized, produces a homopolymer having a T of less than 25 °C. g In an embodiment of an oligomer in which only one type of low T g monomer unit is present, the T of the low T g monomer unit g is the T of the homopolymer of one type of low T g monomer unit. g In an embodiment of an oligomer in which two or more distinct low T g monomer units are present, the T of the low T g monomer units of the oligomer g is the Fox average T of the combination of low T i monomer units, where in equation (1), the individual mass fractions ω g are not based on the total mass of the entire oligomer, but rather on the total mass of all low T g monomer units (i.e., monomer units having a T of less than 25 °C) present in the oligomer, and the Fox average T g of each individual low T g monomer unit in the oligomer. g is collectively referred to.

[0053] The term "photoinitiator" can be considered to be any type of substance that, when exposed to radiation (e.g., actinic radiation), forms species that initiate the reaction and curing of the polymerizable organic substances present in the curable composition.

[0054] The term "chromophore" as used herein refers to a Nolish II type light absorbing molecule that becomes excited upon absorbing light. From this excited state, the molecule can interact or react with other molecules to generate reactive radical species.

[0055] The term "independently selected" as used herein refers to substituents, such as Z 1 Z 2 Z 3 and Z 4 which may be the same or different (e.g., Z 1 Z 2 Z 3 and Z 4 may all be -CH3, or Z 1 and Z 2 may be -CH3 and Z 3 and Z 4 may be -H, etc.). The chemical names associated with the substituents are intended to convey the chemical structure recognized in the art as corresponding to the structure of that chemical name. Thus, the chemical names are not intended to exclude, but rather to supplement and exemplify, the structure definitions known to those skilled in the art.

[0056] When used to describe a given carbon atom-containing chemical group, the parenthetical expression of the form "(C x -C y )" means that the unsubstituted form of the chemical group contains x to y and has x to y carbon atoms. For example, (C1-C 20 ) hydrocarbyl is a hydrocarbyl group having from 1 to 20 carbon atoms in its unsubstituted form. In some embodiments and general structures, a given chemical group may be substituted by one or more substituents such as R S . The R S -substituted version of a chemical group defined using the parenthetical "(C x -C y )" may contain more than y carbon atoms depending on the identity of any group R S . For example, "(C1-C 20 substituted with exactly one group R S“alkyl (wherein R S is phenyl (-C6H5))” may contain from 7 to 27 carbon atoms. Thus, generally, when a chemical group defined using the bracketed “(C x -C y )” is substituted with one or more carbon atom-containing substituents R S , the minimum and maximum total numbers of carbon atoms of the chemical group are determined by adding the sum of the combinations of the numbers of carbon atoms from all the carbon atom-containing substituents R S to both x and y.

[0057] The term “-H” means a hydrogen atom that is covalently bonded to an atom other than hydrogen. “Hydrogen” and “-H” are interchangeable and have the same meaning unless specifically specified otherwise.

[0058] The term “(C1-C 30 ) hydrocarbyl” means a monovalent hydrocarbon of 1 to 30 carbon atoms, each monovalent hydrocarbon being aromatic or non-aromatic, saturated or unsaturated, straight-chain or branched-chain, cyclic (having 3 or more carbon atoms, including monocyclic and polycyclic, fused and non-fused polycyclic, and bicyclic) or acyclic, and being substituted with one or more R S or unsubstituted. In this disclosure, (C1-C 30 ) hydrocarbyl can be unsubstituted or substituted (C1-C 30 ) alkyl, (C3-C 30 ) cycloalkyl, or (C6-C 30 ) aryl.

[0059] The term “(C2-C 30 ) alkyl” means a saturated straight-chain or branched-chain monovalent hydrocarbon of 2 to 30 carbon atoms, unsubstituted or substituted with one or more R S . Examples of unsubstituted (C2-C 30 ) alkyl are unsubstituted (C2-C 20 ) alkyl; unsubstituted (C6-C 25) Alkyl; unsubstituted (C4-C8) alkyl; 1-butyl; 2-butyl; 2-methylpropyl; 1,1-dimethylethyl; 1-pentyl; 1-hexyl; 1-heptyl; 1-nonyl; and 1-decyl. Examples of substituted (C2-C 30 ) alkyl are substituted (C2-C 20 ) alkyl, substituted (C2-C 10 ) alkyl.

[0060] The term “(C6-C 40 ) aryl” means an unsubstituted or (substituted with one or more R S ) monocyclic, bicyclic, or tricyclic aromatic monovalent hydrocarbon having from 6 to 40 carbon atoms, at least from 6 to 14 of which are aromatic ring carbon atoms. Monocyclic aromatic monovalent hydrocarbons contain one aromatic ring; bicyclic aromatic monovalent hydrocarbons have two rings; and tricyclic aromatic monovalent hydrocarbons have three rings. When bicyclic or tricyclic aromatic monovalent hydrocarbons are present, at least one of the rings of the monovalent hydrocarbon is aromatic. The other rings of the aromatic monovalent hydrocarbon may be independently fused or unfused and may be aromatic or non-aromatic. Examples of unsubstituted (C6-C 40 ) aryl include unsubstituted (C6-C 20 ) aryl, unsubstituted (C6-C 18 ) aryl; 2-(C1-C5) alkyl-phenyl; phenyl; fluorenyl; tetrahydrofluorenyl; idacenyl; hexahydracenyl; hexahydroindacenyl; indenyl; dihydroindenyl; naphthyl; tetrahydronaphthyl; and phenanthrene. Examples of substituted (C6-C 40 ) aryl include substituted (C1-C 20 ) aryl; and substituted (C6-C 18 ) aryl.

[0061] The term “(C6-C 12 ) cycloalkyl” means a saturated cyclic monovalent hydrocarbon of 6 to 12 carbon atoms, which is unsubstituted or substituted. Other cycloalkyl groups (e.g., (C x -C yCycloalkyl) likewise has from x to y carbon atoms and is defined as unsubstituted or substituted with one or more R S as defined herein. Examples of unsubstituted (C6-C 12 ) cycloalkyl are unsubstituted (C6-C8) cycloalkyl, unsubstituted (C6-C 10 ) cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Examples of substituted (C6-C 12 ) cycloalkyl are substituted (C6-C8) cycloalkyl, substituted (C6-C 10 ) cycloalkyl, isobornyl, and 3,3,5-trimethylcyclohexyl.

[0062] The term "heteroatom" refers to an atom other than hydrogen or carbon. Examples of heteroatoms include O, S, N, and Si. The term "heterohydrocarbon" refers to a molecule or molecular framework in which one or more carbon atoms of a hydrocarbon have been replaced by heteroatoms. The term "(C1-C 30 ) heterohydrocarbyl" means a monovalent heterohydrocarbon having from 1 to 30 carbon atoms, and the term "(C1-C 30 ) heterohydrocarbylene" means a divalent heterohydrocarbon having from 1 to 30 carbon atoms. The heterohydrocarbons of (C1-C 30 ) heterohydrocarbyl or (C1-C 30 ) heterohydrocarbylene have one or more heteroatoms. The valence or point of attachment of a heterohydrocarbyl can be on a carbon atom or a heteroatom. The two valences of a heterohydrocarbylene can be on a single carbon atom or a single heteroatom. In addition, one of the two valences or points of attachment of a diradical can be on a carbon atom and the other on another carbon atom; one of the two valences or points of attachment can be on a carbon atom and the other on a heteroatom; or one of the two valences or points of attachment can be on a heteroatom and the other valence or point of attachment can be on another heteroatom. Each (C1-C 30 ) heterohydrocarbyl and (C1-C 30)A hetero hydrocarbylene can be unsubstituted or substituted, aromatic or non-aromatic, saturated or unsaturated, straight-chain or branched-chain, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic), or acyclic.

[0063] The term "saturated" means lacking carbon-carbon double bonds, carbon-carbon triple bonds, and (in the case of heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds. When a saturated chemical group is substituted with one or more substituents R S one or more double bonds and / or triple bonds may or may not optionally be present in the substituent R S . The term "unsaturated" means containing one or more carbon-carbon double bonds, carbon-carbon triple bonds, or (in the case of heteroatom-containing groups) one or more carbon-nitrogen, carbon-phosphorus, or carbon-silicon double bonds, and any double bonds that may be present in the substituent R S or, if any, double bonds that may be present in a (hetero)aromatic ring are not included.

[0064] The term "linker" means a polyvalent group. A linker can connect at least two parts of a compound, particularly from 2 to 16 parts of a compound together. For example, a linker that connects two parts of a compound is called a divalent linker, and a linker that connects three parts of a compound is called a trivalent linker.

[0065] As used herein, the "weight average molecular weight ("M w ")" is quantified by size exclusion chromatography (SEC) using poly(methyl methacrylate) reference standards and tetrahydrofuran as the solvent, unless otherwise explicitly specified.

[0066] Embodiments of the acrylic copolymers described herein that contain a pendant Norrish type II photoinitiator having an absorption band at a long wavelength (i.e., thioxanthone, anthraquinone, or camphorquinone) when mixed with at least one (meth)acrylate monomer and the resulting composition is photocured have been found to sometimes have less yellowing. Without being bound by theory, it is believed that the reason for the relatively high yellowing shown by compositions cured with small molecule Norrish type II photoinitiators having an absorption band at a long wavelength is that the small molecule photoinitiators react during curing to form dimers and other by-products, which cause yellowing in the cured composition. When a photoinitiator covalently bonds to an acrylic copolymer, such as an embodiment of the acrylic copolymers described herein, the opportunity for photoinitiator dimerization is believed to be significantly reduced. Further, since embodiments of the acrylic copolymers described herein are incorporated into the polymer framework during photocuring, the photoinitiator moiety may show little or no migration.

[0067] [Acrylic copolymer] The acrylic copolymers (also referred to as oligomers) herein contain at least one polymerized chromophore monomer unit as defined herein. The acrylic copolymers herein are polymerized high T g monomer units, polymerized low T g monomer units, or at least one polymerized high T g monomer units and at least one polymerized low T g monomer units, and further contain at least one polymerized monomer unit selected from combinations of monomer units. The acrylic copolymers herein optionally contain at least one polymerized additional monomer unit as defined herein. The acrylic copolymer may not contain polymerized monomer units other than polymerized high T g monomer units, polymerized low T g monomer units, polymerized chromophore monomer units, and optionally polymerized additional monomer units. Polymerized high T g monomer units, polymerized low T gThe total weight of the monomer units, polymerized chromophore monomer units, and polymerized additional monomer units can account for at least 97%, particularly at least 98%, more specifically at least 99%, and even more specifically 100% of the total weight of the acrylic copolymer.

[0068] In an embodiment, the acrylic copolymer comprises from 0 wt% to 99.9 wt% of polymerized high-T g monomer units, from 0 wt% to 99.9 wt% of polymerized low-T g monomer units, from 0.1 wt% to 40 wt% of polymerized chromophore monomer units, and from 0 to 20 wt% of polymerized additional monomer units, provided that the acrylic copolymer comprises a total of polymerized high-T g monomer units and polymerized low-T g monomer units of at least 40 wt%, or at least 50 wt%, or at least 60 wt%, or at least 70 wt%, or at least 80 wt%, or at least 90 wt%.

[0069] In one or more embodiments, the acrylic copolymer comprises a reaction product of a high-T g monomer having a glass transition temperature (T g ) of 25 °C or higher, a chromophore monomer comprising a moiety selected from thioxanthone, anthraquinone, or camphorquinone, and optionally at least one additional monomer. According to one or more embodiments, the chromophore monomer comprises a moiety comprising thioxanthone.

[0070] In one or more embodiments, the acrylic copolymer comprises a reaction product of a low-T g monomer having a T g of less than 25 °C, a chromophore monomer comprising a moiety selected from thioxanthone, anthraquinone, or camphorquinone, and optionally at least one additional monomer. According to one or more embodiments, the chromophore monomer comprises a moiety comprising thioxanthone.

[0071] In one or more embodiments, the acrylic copolymer has a glass transition temperature (Tg) of 25 °C or higher g ) and has a high Tg g monomer, a low Tg g having a Tg of less than 25 °C g monomer, a chromophore monomer containing a moiety selected from thioxanthone, anthraquinone, or camphorquinone, and an optional at least one additional monomer. According to one or more embodiments, the chromophore monomer contains a moiety containing thioxanthone.

[0072] In an embodiment, the acrylic copolymer has the formula (I): TIFF2025523936000003.tif53170(In the above formula, - Each A 1 is independently a (C1-C 30 ) hydrocarbyl or a (C1-C 30 ) heterohydrocarbyl, preferably a (C1-C 30 ) hydrocarbyl; - Each A 2 is independently a (C4-C 30 ) hydrocarbyl or a (C4-C 30 ) heterohydrocarbyl, preferably a (C4-C 30 ) hydrocarbyl; - Each A 3 is independently a residue containing a monovalent radical containing a moiety selected from thioxanthone, anthraquinone, or camphorquinone, preferably thioxanthone; - Each A 4 is independently a (C1-C 30 ) hydrocarbyl or a (C1-C 30 ) heterohydrocarbyl; - Z 1 , Z 2 , Z 3 , and Z 4 are independently -H or (C1-C4) alkyl, preferably -H or -CH3; - m is the weight fraction of the high Tg g monomer and is from 0 to 0.999; - n is the low Tgg is from 0 to 0.999 in terms of the weight fraction of the monomer; - p is from 0.001 to 0.4 in terms of the weight fraction of the chromophore monomer; - q is from 0 to 0.2 in terms of the weight fraction of the additional monomer; - m + n is 0.4 or more; and - m + n + p + q = 1) has.

[0073] In an embodiment, m is from 0.001 to 0.999, preferably from 0.01 to 0.50; n is from 0.001 to 0.999, preferably from 0.50 to 0.98; and m + n is 0.6 or more.

[0074] [High T g monomer unit] The acrylic copolymer disclosed herein may contain polymerized high T g monomer units. High T g monomer units are different from low T g monomer units, chromophore monomer units, and additional monomer units. Thus, high T g monomer units may not contain any of the following groups: - chromophore moiety - functional groups defined below for the additional monomer unit.

[0075] Polymerized high T g monomer units may be the same or a combination of multiple types of different monomer units, such as, for example, two different monomer units, three different monomer units, four different monomer units, or more than four different monomer units. In an embodiment, high T g monomer units have a glass transition temperature (T g ) of 25 °C or higher or a Fox equation average T g . As defined herein, the reference herein to T g for a monomer is to the T g of the homopolymer formed from that monomer.refers to. In embodiments where the acrylic copolymer comprises two or more distinct high T g monomer units, such as a combination of methyl (meth)acrylate and isobornyl (meth)acrylate, T g is, as previously described herein, the Fox equation average T g of the high T g monomer units. In embodiments, the Fox equation average T g of the high T g monomer units is 25 °C or higher, such as 30 °C or higher, 35 °C or higher, 40 °C or higher, 45 °C or higher, 50 °C or higher, 55 °C or higher, 60 °C or higher, 65 °C or higher, 70 °C or higher, 75 °C or higher, or 80 °C or higher. In embodiments, the high T g monomer units have a T g that can be from 25 °C to 200 °C, from 25 °C to 150 °C, from 25 °C to 130 °C, from 30 °C to 200 °C, from 30 °C to 150 °C, from 30 °C to 130 °C, from 35 °C to 200 °C, from 35 °C to 150 °C, from 35 °C to 130 °C, from 40 °C to 200 °C, from 40 °C to 150 °C, from 40 °C to 130 °C, from 45 °C to 200 °C, from 45 °C to 150 °C, from 45 °C to 130 °C, from 50 °C to 200 °C, from 50 °C to 150 °C, from 50 °C to 130 °C, from 55 °C to 200 °C, from 55 °C to 150 °C, from 55 °C to 130 °C, from 60 °C to 200 °C, from 60 °C to 150 °C, from 60 °C to 130 °C, from 65 °C to 200 °C, from 65 °C to 150 °C, from 65 °C to 130 °C, from 70 °C to 200 °C, from 70 °C to 150 °C, from 70 °C to 130 °C, from 75 °C to 200 °C, from 75 °C to 150 °C, or even from 75 °C to 130 °C, or any and all partial ranges formed from any of these endpoints.

[0076] When the acrylic copolymer comprises both high T g monomer units and low T g monomer units (i.e., m and n in formula (I) are not zero), the Fox equation average T g of the high T g monomer units is higher than the Fox equation average T g of the low T g monomer units. In embodiments, the Fox equation average T g of the high T g monomer units is higher than the low T gThe Fox equation average T of the monomer unit g is at least 20 °C higher. In an embodiment, the high T g The Fox equation average T of the monomer unit g and the low T g The Fox equation average T of the monomer unit g The difference between them is more than 20 °C, for example, more than 25 °C, more than 30 °C, more than 35 °C, more than 40 °C, more than 45 °C, more than 50 °C, more than 55 °C, more than 60 °C, more than 65 °C, more than 70 °C, more than 75 °C, more than 80 °C, more than 85 °C, more than 90 °C, more than 95 °C, more than 100 °C, more than 105 °C, more than 110 °C, more than 115 °C, or more than 120 °C. In an embodiment, the high T g The Fox equation average T of the monomer unit g and the low T g The Fox equation average T of the monomer unit g The difference between them is from 20 °C to 200 °C. As a non-limiting example, the high T g The Fox equation average T of the monomer unit g and the low T g The Fox equation average T of the monomer unit gThe difference from is any and all partial ranges that can be formed from 20°C to 200°C, 20°C to 150°C, 20°C to 120°C, 20°C to 100°C, 20°C to 90°C, 20°C to 80°C, 20°C to 70°C, 20°C to 60°C, 20°C to 50°C, 20°C to 40°C, 20°C to 30°C, 30°C to 200°C, 30°C to 150°C, 30°C to 120°C, 30°C to 100°C, 30°C to 90°C, 30°C to 80°C, 30°C to 70°C, 30°C to 60°C, 30°C to 50°C, 30°C to 40°C, 40°C to 200°C, 40°C to 150°C, 40°C to 120°C, 40°C to 100°C, 40°C to 90°C, 40°C to 80°C, 40°C to 70°C, 40°C to 60°C, 40°C to 50°C, 50°C to 200°C, 50°C to 150°C, 50°C to 120°C, 50°C to 100°C, 50°C to 90°C, 50°C to 80°C, 50°C to 70°C, 50°C to 60°C, 60°C to 200°C, 60°C to 150°C, 60°C to 120°C, 60°C to 100°C, 60°C to 90°C, 60°C to 80°C, 60°C to 70°C, 70°C to 200°C, 70°C to 150°C, 70°C to 120°C, 70°C to 100°C, 70°C to 90°C, 70°C to 80°C, 80°C to 200°C, 80°C to 150°C, 80°C to 120°C, 80°C to 100°C, or 80°C to 90°C, or any of these endpoints.

[0077] High T g The monomer unit consists of one or more (meth)acrylate monomers, preferably one or more monofunctional (meth)acrylate monomers.

[0078] In an embodiment, High T g The monomer unit is monovalent. In other embodiments, High T g The monomer unit may be polyvalent, in which case each individual monomer unit contains two or more active sites that participate in crosslinking during curing. Examples of monovalent monomer units may include ethyl methacrylate and tert-butyl acrylate. Examples of polyvalent monomer units may include divalent monomer units such as dicyclopentadienyl diacrylate.

[0079] In an embodiment, High Tg Each of the monomer units (before being polymerized to form the backbone of the acrylic copolymer) is independently of the formula (II): TIFF2025523936000004.tif44170(wherein, - A 1 is (C1-C 30 ) hydrocarbyl or (C1-C 30 ) heterohydrocarbyl, preferably (C1-C 30 ) hydrocarbyl; and - Z 1 is -H or -CH3) may follow.

[0080] For example, in an embodiment, A 1 is selected from methyl, ethyl, isopropyl, isobutyl, tert-butyl, substituted or unsubstituted (C6-C 12 ) cycloalkyl, substituted or unsubstituted (C6-C 12 ) aryl or combinations thereof. In an embodiment, A 1 is selected from methyl, tert-butyl, isobornyl, cyclohexyl, or 3,3,5-trimethylcyclohexyl, phenyl, benzyl or combinations thereof.

[0081] Said embodiment is similarly applicable to A 1 in the acrylic copolymer of formula (I).

[0082] In an embodiment, high T gThe monomer units can include, but are not limited to, (hydrocarbyl) acrylate ester monomers including (alkyl) acrylate ester monomers, (cycloalkyl) acrylate ester monomers, or (aryl) acrylate ester monomers. Examples of (alkyl) acrylate ester monomers include acrylate and (meth) acrylate ester monomers such as methyl (meth) acrylate. Examples of (cycloalkyl) acrylate ester monomers include acrylate ester monomers and IBOA, IBOMA. Examples of (aryl) acrylate ester monomers include acrylate ester monomers and phenyl (meth) acrylate and benzyl (meth) acrylate.

[0083] Suitable high T g Examples of monomer units can include, but are not limited to, 2-phenylethyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, tert-butyl acrylate, octadecyl methacrylate, octadecyl acrylate, propyl methacrylate, benzyl methacrylate, isobutyl methacrylate, ethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, isopropyl methacrylate, isobornyl acrylate, methyl methacrylate, isobornyl methacrylate, phenyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, 4-tert-butylcyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, substituted or unsubstituted (C6-C 12 ) cycloalkyl (meth) acrylate, adamantyl (meth) acrylate, tricyclodecanemethanol mono (meth) acrylate, or monomers selected from combinations thereof can be included.

[0084] Preferably, the high T of the acrylic copolymer gThe monomer unit is selected from methyl methacrylate, tert-butyl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, and benzyl (meth)acrylate or combinations thereof.

[0085] The polymerized high T in the acrylic copolymer g The weight fraction of the monomer varies according to the desired properties of the acrylic copolymer, such as T g , molecular weight, and gel content after curing.

[0086] As described herein, m in formula (I) is the polymerized high T gIt is the weight fraction of the monomer. In some embodiments, m is from 0 to 0.999, provided that the sum of m and n is at least 0.4. In further embodiments, m is 0.01 or more, such as 0.05 or more, 0.1 or more, 0.15 or more, 0.2 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, or 0.60 or more. In an embodiment, m is from 0.10 to 0.95, from 0.10 to 0.95, from 0.10 to 0.90, from 0.10 to 0.85, from 0.10 to 0.80, from 0.10 to 0.75, from 0.10 to 0.70, from 0.10 to 0.60, from 0.10 to 0.50, from 0.10 to 0.40, from 0.10 to 0.30, from 0.10 to 0.20, from 0.20 to 0.95, from 0.20 to 0.90, from 0.20 to 0.85, from 0.20 to 0.80, from 0.20 to 0.70, from 0.20 to 0.60, from 0.20 to 0.50, from 0.20 to 0.40, from 0.30 to 0.95, from 0.30 to 0.90, from 0.30 to 0.85, from 0.30 to 0.80, from 0.30 to 0.70, from 0.30 to 0.60, from 0.30 to 0.50, from 0.30 to 0.40, from 0.40 to 0.95, from 0.40 to 0.90, from 0.40 to 0.85, from 0.40 to 0.80, from 0.40 to 0.70, from 0.40 to 0.60, from 0.40 to 0.50, from 0.50 to 0.95, from 0.50 to 0.90, from 0.50 to 0.85, from 0.50 to 0.95, from 0.50 to 0.90, from 0.50 to 0.85, from 0.50 to 0.80, from 0.50 to 0.70, from 0.50 to 0.60, from 0.60 to 0.95, from 0.60 to 0.90, from 0.60 to 0.85, from 0.60 to 0.80, from 0.60 to 0.70, from 0.70 to 0.95, from 0.70 to 0.90, from 0.70 to 0.85, or from 0.70 to 0.80.

[0087] [Low T g monomer unit] The acrylic copolymers disclosed herein may include low T g monomer units. The low T g monomer units are distinguished from the high T g monomer units, the chromophore monomer units, and the additional monomer units. Thus, the low T gThe monomer unit may not contain any of the following groups: - A chromophore moiety - A functional group defined below for additional monomer units.

[0088] In an embodiment, the acrylic copolymer comprises polymerized high-T g monomer units optionally combined with polymerized low-T g monomer units. The polymerized low-T g monomer units can be the same or a combination of multiple types of different monomer units, such as two different monomer units, three different monomer units, four different monomer units, or more than four different monomer units. In an embodiment, the low-T g monomer units can have a glass transition temperature (T g ) below 25 °C or a Fox equation average T g below 25 °C. As defined herein, references to the T g of a monomer refer to the T g of the homopolymer formed from that monomer. In embodiments where the acrylic copolymer contains two or more different low-T g monomer units, T g refers to the Fox equation average T g of the low-T g monomer units as previously defined herein. In an embodiment, the low-T g monomer units have a Fox equation average T g below 25 °C, for example below 20 °C, below 15 °C, below 10 °C, below 5 °C, below 0 °C, below -5 °C, below -10 °C, below -15 °C, below -20 °C, or below -30 °C. In an embodiment, the low-T g monomer units have a Fox equation average T g from -150 °C to 24 °C, for example preferably from -80 °C to 0 °C, and most preferably from -60 °C to -10 °C.

[0089] The low-T g monomer units consist of one or more (meth)acrylate monomers, preferably one or more monofunctional (meth)acrylate monomers.

[0090] In an embodiment, the low-T g monomer unit can be monovalent. In an embodiment, the low-T g monomer unit may include (meth)acrylate monomers including acrylate monomers and methacrylate monomers. Examples of acrylate monomers include sec-butyl acrylate monomer and n-butyl acrylate monomer. Examples of methacrylate monomers include butyl methacrylate monomer and pentyl methacrylate monomer.

[0091] In an embodiment, the low-T g each of the monomer units (before being polymerized into the backbone of the acrylic copolymer) independently has the formula (II): TIFF2025523936000005.tif44170(In the above formula, - A 2 is a (C4-C 30 ) hydrocarbyl or a (C4-C 30 ) heterohydrocarbyl, preferably a (C4-C 30 ) hydrocarbyl; and - Z 2 is -H or -CH3) can follow.

[0092] In an embodiment, A 2 is a linear or branched (C4-C 30 ) alkyl. In an embodiment, A 2 is selected from n-butyl, isobutyl, hexyl, 2-ethylhexyl, isooctyl, isodecyl, tridecyl, lauryl, or a combination thereof.

[0093] The above embodiment is similarly applicable to A 2 of the acrylic copolymer of formula (I).

[0094] The low-T of the acrylic copolymer gFurther examples of monomer units include, but are not limited to, monomer units selected from n-butyl (meth)acrylate, isobutyl acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate, nonyl acrylate, decyl (meth)acrylate, octyl (meth)acrylate, propyl acrylate, isobutyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, ethyl acrylate, sec-butyl acrylate, dodecyl acrylate, tetradecyl (meth)acrylate, isopropyl acrylate, pentyl (meth)acrylate, benzyl acrylate, cyclohexyl acrylate, hexadecyl (meth)acrylate, 2-methylbutyl acrylate, 2-octyl acrylate, or combinations thereof.

[0095] Preferably, the low T of the acrylic copolymer g The monomer unit is n-butyl acrylate.

[0096] The polymerized low T in the acrylic copolymer g The weight fraction of the monomer unit varies depending on the desired properties of the acrylic copolymer, such as T g , molecular weight, and gel content after curing.

[0097] As described herein, n in formula (I) is the polymerized low T in the acrylic copolymer gIt is the weight fraction of the monomer unit. In some embodiments, n is from 0 to 0.999, provided that the sum of m and n is at least 0.4. In an embodiment, n is 0.001 or more, for example 0.02 or more, 0.05 or more, 0.10 or more, 0.15 or more, 0.20 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, 0.65 or more, 0.70 or more, 0.75 or more, or 0.80 or more.In an embodiment, n is from 0.001 to 0.989, from 0.001 to 0.90, from 0.001 to 0.80, from 0.001 to 0.70, from 0.001 to 0.60, from 0.001 to 0.50, from 0.001 to 0.40, from 0.001 to 0.30, from 0.001 to 0.20, from 0.001 to 0.10, from 0.001 to 0.05, from 0.01 to 0.989, from 0.01 to 0.90, from 0.01 to 0.80, from 0.01 to 0.70, from 0.01 to 0.60, from 0.01 to 0.50, from 0.01 to 0.40, from 0.01 to 0.30, from 0.01 to 0.20, from 0.01 to 0.10, from 0.01 to 0.05, from 0.05 to 0.989, from 0.05 to 0.90, from 0.05 to 0.80, from 0.05 to 0.70, from 0.05 to 0.60, from 0.05 to 0.50, from 0.05 to 0.40, from 0.05 to 0.30, from 0.05 to 0.20, from 0.05 to 0.10, from 0.10 to 0.989, from 0.10 to 0.90, from 0.10 to 0.80, from 0.10 to 0.70, from 0.10 to 0.60, from 0.10 to 0.50, from 0.10 to 0.40, from 0.10 to 0.30, from 0.10 to 0.20, from 0.20 to 0.989, from 0.20 to 0.90, from 0.20 to 0.80, from 0.20 to 0.70, from 0.20 to 0.60, from 0.20 to 0.50, from 0.20 to 0.40, from 0.20 to 0.30, from 0.30 to 0.989, from 0.30 to 0.90, from 0.30 to 0.80, from 0.30 to 0.70, from 0.30 to 0.60, from 0.30 to 0.50, from 0.30 to 0.40, from 0.40 to 0.989, from 0.40 to 0.90, from 0.40 to 0.80, from 0.40 to 0.70, from 0.40 to 0.60, from 0.40 to 0.50, from 0.50 to 0.989, from 0.50 to 0.90, from 0.50 to 0.80, from 0.50 to 0.70, from 0.50 to 0.60, from 0.60 to 0.989, from 0.60 to 0.90, from 0.60 to 0.80, from 0.60 to 0.70, from 0.70 to 0.989, from 0.70 to 0.90, from 0.70 to 0.80, from 0.80 to 0.989, from 0.80 to 0.90, or from 0.90 to 0.989.

[0098] The acrylic copolymer has a low T g monomer unit and a high T g monomer unit. When both are included, the low T gMonomer unit and high T g The weight ratio of the monomer units can be adjusted according to the desired properties of the acrylic copolymer, such as T g and the gel content after curing. In an embodiment, the low T g monomer unit and high T g The weight ratio of the monomer units can be from 10:1 to 1:9, 5:1 to 1:9, 2:1 to 1:9, 1:1 to 1:9, 10:1 to 1:5, 5:1 to 1:5, 2:1 to 1:5, 1:1 to 1:5, 10:1 to 1:5, or any and all partial ranges formed from any of these endpoints.

[0099] [Chromophore monomer unit] In addition to at least one polymerized high T g monomer unit, or at least one polymerized low T g monomer unit, or preferably at least one polymerized high T g monomer unit and at least one polymerized low T g monomer unit combination, the acrylic copolymer further comprises at least one polymerized chromophore monomer unit. The chromophore monomer unit is distinct from the high T g monomer unit, low T g monomer unit and additional monomer units.

[0100] The polymerized chromophore monomer unit acts as a photoinitiator and can induce the curing of the acrylic copolymer by radiation. A photoinitiator is generally a moiety that generates reactive species (ions or radicals) upon absorption of light and initiates one or several chemical reactions or transformations.

[0101] Overlapping chromophore monomer units contain a free radical photoinitiator moiety. The photoinitiator moiety can be selected to be susceptible to activation by photons of wavelengths associated with actinic radiation (e.g., ultraviolet light, visible light) intended to cure the curable composition. A Norrish type II (i.e., non-cleaving) photoinitiator moiety does not decompose upon excitation, so there is a lower likelihood of small molecules leaching from the matrix composition. For reference, see, for example, A. Gilbert, J. Baggott: “Essentials of Molecular Photochemistry”, Blackwell, London, 1991. The excited non-cleaving photoinitiator does not decompose into radicals upon excitation, but abstracts a hydrogen atom from an organic molecule or, more efficiently, an electron from an electron donor (such as an amine or thiol). By electron transfer, a radical anion is formed on the photoinitiator and a radical cation is formed on the electron donor. Subsequently, proton transfer from the radical cation to the radical anion generates two uncharged radicals; of these, the radical on the electron donor is sufficiently reactive to abstract a hydrogen atom from most substrates.

[0102] The photoinitiator moiety includes a thioxanthone moiety, an anthraquinone moiety, or a camphorquinone moiety. Thioxanthone, anthraquinone, and camphorquinone are examples of Norrish type II chromophores. Most amines having a C-H bond at the α-position of the nitrogen atom and many thiols are electron donors.

[0103] In an embodiment, the polymerized chromophore monomer unit is a (meth)acrylate monomer having a Norrish type II chromophore moiety selected from thioxanthone, anthraquinone, or camphorquinone.

[0104] In an embodiment, each of the chromophore monomer units (before polymerization into the backbone of the acrylic copolymer) is independently of formula (IV): TIFF2025523936000006.tif37170(wherein, A 3 is a monovalent residue containing a Norrish type II chromophore, in particular A3 is X or -L-X; L is a (C1-C 10 ) heterohydrocarbylene linker; X is a monovalent residue of a Type II Nolish chromophore moiety selected from thioxanthone, anthraquinone or camphorquinone, preferably thioxanthone; Z 3 is -H or -CH3) can follow.

[0105] In an embodiment, A of formula (IV) 3 is X or -L-X, where L is a (C1-C 10 ) heterohydrocarbylene linker and X is a monovalent residue of a Type II Nolish chromophore. As used in this disclosure, the term "residue" refers to an atom or group of atoms that forms part of a molecule such as part of a Type II Nolish chromophore. In other embodiments, A 3 is a monovalent residue of a Type II Nolish chromophore. In an embodiment, X can be a monovalent residue of any one of the above Type II Nolish chromophores. In an embodiment, A 3 is a monovalent residue containing thioxanthone, anthraquinone or camphorquinone. In an embodiment, A 3 is a monovalent residue containing thioxanthone.

[0106] In particular, A of formula (I) 3 is the following formula (IVa) or (IVb): TIFF2025523936000007.tif94170(wherein in formula (IVa) and formula (IVb), L 1 is alkylene; L 2 is a divalent linker containing at least 2 carbon atoms; Each R 1 and R 2 is -H, halogen, alkyl, cycloalkyl, heterocycloalkyl, alkoxy, aryloxy, thioalkyl, thioaryl, alkenyl, alkynyl, aryl, aralkyl, alkaryl, heteroaryl, -C(=O)Ra 、 -NR b R c 、 alkylamino, alkylthiol, haloalkyl, -NO2, -CN, -C(=O)OR d 、 -C(=O)NR b R c and is independently selected from; R a is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl and optionally substituted aryl; R b 、 R c and R d are independently selected from -H, alkyl and aryl) may have.

[0107] In particular, in formula (IVa) and formula (IVb), R 1 and R 2 are independently -H, halogen, alkyl or alkoxy. More specifically, R 1 and R 2 are independently H or alkyl. Even more specifically, R 1 and R 2 are independently H or methyl. Even more specifically, R 1 and R 2 are all -H.

[0108] In formula (IVa) and formula (IVb), L 1 is alkylene. In particular, each L 1 can independently be a straight-chain or branched alkylene having 1 to 6, 1 to 4, or 1 to 2 carbon atoms. More specifically, L 1 is -CH2- or -CH(CH3)-. Even more specifically, L 1 is -CH2-.

[0109] In formula (IVa) and formula (IVb), L 2 is a divalent linker containing at least 2 carbon atoms. L 2can be an aromatic, aliphatic or alicyclic hydrocarbon linker, a polyether linker, a polyester linker, a polycarbonate linker, a polycaprolactone linker, a polyurethane linker, a polyorganosiloxane linker, a polybutadiene linker, and combinations thereof. In particular, L 2 can be selected from an aromatic, aliphatic or alicyclic hydrocarbon linker, a polyether linker, a polyester linker, and combinations thereof.

[0110] In formulas (IVa) and (IVb), L 2can be a -CH2-CH(OH)-CH2- or a residue of a diol. As used herein, the term "residue of a diol" means a linker obtained by removing two OH groups from a diol. Examples of suitable diols include 1,3-propylene glycol, 1,3- or 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 3,3-dimethyl-1,5-pentanediol, neopentyl glycol, 2,4-diethyl-1,5-pentanediol, cyclohexanediol, cyclohexane-1,4-dimethanol, norbornenedimethanol, norbornanedimethanol, tricyclodecanediol, tricyclodecanedimethanol, bisphenol A, B, F or S, hydrogenated bisphenol A, B, F or S, di-, tri- or tetraethylene glycol, di-, tri- or tetrapropylene glycol, di-, tri- or tetrabutylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly(ethylene glycol-co-propylene glycol), dianhydrohexitol (i.e., isosorbide, isomannide, isoidide), polybutadiene polyol, polyester polyol, polyether polyol, polyorganosiloxane polyol, polycarbonate polyol, and their alkoxylated (e.g., ethoxylated and / or propoxylated) derivatives, and derivatives obtained by ring-opening polymerization of ε-caprolactone initiated with one of the aforementioned polyols are included.

[0111] In formulas (IVa) and (IVb), L 2 can be a -CH 2- CH(OH)-CH2- or a divalent linker selected from one of formulas (A) to (E): TIFF2025523936000008.tif63170 (In the above formula, R 22, R ’22 , R 25 , R ’25 , R 29 , R ’29 , R 30 and R ’30 are independently H or alkyl; R 23 , R ’23 , R 24 , R ’24 , R 26 , R ’26 , R 27 , R ’27 , R 28 and R ’28 are independently H or methyl; a is from 2 to 20; b, d, and d' are independently from 2 to 4; c is from 1 to 20; e and e' are independently from 0 to 20, provided that at least one of q and q' is not 0; f is from 2 to 20; g is from 3 to 12; h is from 1 to 20; i is from 2 to 8; j is from 2 to 20; k is from 2 to 30; l is from 1 to 20)

[0112] In particular, in formula (IVa) and formula (IVb), L 2 is -CH 2-It is CH(OH)-CH2-, or an alkylene such as 1,3-propanediyl, 1,3- or 1,4-butanediyl, 1,5-pentanediyl, 1,6-hexanediyl, 1,8-octanediyl, 1,9-nonanediyl, 1,10-decanediyl, 1,12-decanediyl, 2-methyl-1,3-propanediyl, 2,2-diethyl-1,3-propanediyl, 3-methyl-1,5-pentanediyl, 3,3-dimethyl-1,5-pentanediyl, 2,2-dimethyl-1,3-propanediyl, 2,4-diethyl-1,5-pentanediyl; an alkoxylation (especially ethoxylation and / or propoxylation) derivative of the aforementioned alkylene; an esterification derivative of the aforementioned alkylene (especially by ring-opening polymerization of lactones such as ε-caprolactone); a divalent linker selected from residues of di-, tri- or tetraethylene glycol, di-, tri- or tetrapropylene glycol, di-, tri- or tetrabutylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, poly(ethylene glycol-co-propylene glycol) and other OH group-free di-, tri-, tetra- or polyoxyalkenes.

[0113] In a preferred embodiment, A of formula (I) 3 is of the following formula (IVc) or (IVd): TIFF2025523936000009.tif76170 (where h is from 1 to 20) and follows one of them.

[0114] Other suitable linker groups can also be used, including those that do not contain a carbonyl group.

[0115] A of formula (IV) 3 All of the embodiments described above for A 3 also apply equally to A of the acrylic copolymer of formula (I).

[0116] The weight fraction of the polymerized chromophore monomer units in the acrylic copolymer can be varied based on factors known in the art, such as the desired curing time, among other factors. As described herein, p in formula (I) is the weight fraction of the polymerized chromophore monomer. In embodiments, p is 0.001 or more, for example 0.005 or more, or 0.01 or more. In embodiments, p is from 0.001 to 0.40, from 0.001 to 0.30, from 0.001 to 0.20, from 0.001 to 0.10, from 0.001 to 0.05, from 0.001 to 0.03, from 0.005 to 0.40, from 0.005 to 0.30, from 0.005 to 0.20, from 0.005 to 0.10, from 0.005 to 0.05, from 0.005 to 0.03, or from 0.005 to 0.02.

[0117] If the acrylic copolymer contains more than one separate type of polymerized chromophore monomer unit, it should be understood that the weight fraction p of the polymerized chromophore monomer units in the acrylic copolymer is equal to the sum of the individual weight fractions of all the separate types of polymerized chromophore monomer units. Further, any monomer containing a chromophore moiety, even if it can be characterized as a high-T g monomer or a low-T g monomer based only on T g should be understood to be considered neither a high-T g monomer nor a low-T g monomer for the calculation of the weight fractions m and n in formula (I).

[0118] [Additional monomer units] The acrylic copolymers disclosed herein optionally contain polymerized additional monomer units. The additional monomer units can include high-T g monomer units, low-T g monomer units, and monomer units copolymerized with the chromophore monomer units. The additional monomer units are different from the high-T g monomer units, low-T g monomer units, and the chromophore monomer units.

[0119] The additional monomer unit may contain a functional group selected from polymerizable groups other than (meth)acrylate groups (i.e., vinyl group, allyl group, conjugated diene group, alkenyl group), acidic groups (i.e., carboxylic acid group, phosphonic acid (-P(=O)(OH)2) group, phosphonate (-P(=O)(OR)2) group, sulfonic acid (-S(=O)2OH) group, sulfonate (-S(=O)2OR) group, phosphoric acid (-O-P(=O)(OR)2) group (wherein each R is independently a counter ion, a hydrogen atom, or an optionally substituted hydrocarbyl)), nitrogen-containing groups (i.e., amino group, cyano group, or a heterocyclic ring having one or more nitrogen ring atoms), hydroxyl group, epoxy group, carbonyl group, acetoacetoxy group, acetoacetamide group, 1,1-dimethyl-3-oxobutyl (diacetone) group, thiol group, silane group, ether bond, ester bond (not included in the (meth)acrylate group), and combinations thereof.

[0120] Preferably, the additional monomer unit contains a functional group selected from acidic groups and nitrogen-containing groups. More preferably, the additional monomer unit contains a functional group selected from a carboxylic acid group, a tertiary amine group, or a heterocyclic ring having one or more nitrogen ring atoms.

[0121] It should be emphasized that (meth)acrylic acid corresponds to the additional monomer. Therefore, the amount by weight of the polymerized (meth)acrylic acid unit, if present, should be considered in the total amount of the polymerized additional monomer units, and not in the total amount of the polymerized high-T g monomer units.

[0122] In an embodiment, the additional monomer unit may include other unsaturated monomer units (other than (meth)acrylic monomer units) such as vinylamide, vinyl ether, vinyl ester, vinyloxazolidinone, (meth)acrylamide, and combinations thereof. In an embodiment, the additional monomer unit may include other monomer units polymerized in an acrylic copolymer such as styrene derivatives and maleimide.

[0123] In an embodiment, the additional monomer unit may include an epoxy, ether, ester, acid, or ketone functional group that is not polymerized within the acrylic copolymer. For example, the additional monomer unit may be caprolactone-extended acrylate (SR495B, Sartomer), cyclic trimethylolpropane formal acrylate (SR531, Sartomer), propoxylated tetrahydrofurfuryl acrylate (SR611, Sartomer), beta-carboxyethyl acrylate, glycidyl methacrylate, or 2-(2-ethoxyethoxy)ethyl acrylate (SR256), neopentyl monomethacrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-cyanobutyl acrylate, 4-cyanobutyl acrylate, 2-cyanoethyl acrylate, cyanomethyl acrylate, and combinations thereof.

[0124] In an embodiment, the additional monomer unit may be a monomer that acts synergistically with the polymerized chromophore monomer unit and / or reduces oxygen inhibition. Oxygen inhibition may limit surface curing and thus may limit the performance of the resulting cured product.

[0125] Common synergistic functional groups that function as synergists for type II photoinitiators can include acidic groups, heterocycles containing one or more nitrogen ring atoms, tertiary amine functional groups, alkyleneoxy functional groups (i.e., one or more oxyalkylene units), mercaptan groups, or other sources of readily abstractable hydrogen. Typical additional monomer units containing synergistic functional groups include monomers such as (meth)acrylic acid, dimethylaminoethyl acrylate (DMAEA), dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl acrylate (DEAEA), diethylaminoethyl methacrylate (DEAEMA), N-vinylpyrrolidone (NVP), N-vinylcaprolactam (VCAP), acryloxymorpholine (ACMO), dimethylacrylamide (DMAC), poly(ethylene oxide) mono(meth)acrylate, hydroxyethyl ethyleneurea (meth)acrylate (HEEU(M)A), reaction products of cyclic anhydrides with hydroxy-functional (meth)acrylates, and combinations thereof.

[0126] In an embodiment, the additional monomer unit may include an amine synergist. Some examples of amine synergists include tertiary amines. When a monomer containing an amine synergist is included in an acrylic copolymer together with a Type II chromophore of the polymerized chromophore monomer unit, the tertiary amine provides an active hydrogen donating site to the excited triplet state of the chromophore, and as a result, a reactive alkylamino radical that can initiate polymerization later is generated. The tertiary amine can also convert non-reactive peroxy species formed by the reaction of oxygen and free radicals into reactive alkylamino radicals, thus reducing the influence of oxygen on curing. Examples of amine synergists that can be components of the polymerized additional monomer include low molecular weight tertiary amines such as triethanolamine and N-methyldiethanolamine (i.e., tertiary amines having a molecular weight of less than 200 g / mol). Other types of amine synergists are aminobenzoates, polymerizable aminobenzoates, polymeric aminobenzoates, and mixtures thereof. Examples of aminobenzoates include ethyl 4-(dimethylamino)benzoate (EDB), pentyl 4-(dimethylamino)benzoate, 2-ethylhexyl 4-(dimethylamino)benzoate, and 2-butoxyethyl 4-(dimethylamino)benzoate (BEDB).

[0127] In an embodiment, the additional monomer unit is a (meth)acrylate monomer having a pendant-type amine functional group.

[0128] Any of the above-mentioned synergists or amine-based synergists can be a pendant residue in the additional monomer unit of the acrylic copolymer herein.

[0129] In an embodiment, each of the additional monomer units (before being polymerized into the backbone of the acrylic copolymer) is independently of the formula (V): TIFF2025523936000010.tif43170(In the above formula, - A 4 is (C1-C 30 )hydrocarbyl or (C1-C 30heterohydrocarbyl, preferably having a functional group selected from an acidic group, a nitrogen-containing group, a hydroxyl group, an epoxy group, a carbonyl group, an acetoacetoxy group, an acetoacetamide group, a 1,1-dimethyl-3-oxobutyl (diacetone) group, a thiol group, a silane group, an ether bond, an ester bond, and combinations thereof (C1-C 30 is a heterohydrocarbyl - Z 4 is -H or -CH3) can follow

[0130] A 4 can contain a monovalent residue of any one of the synergists considered above. In an embodiment, Z 4 is -H or -CH3, and A 4 is -C(=O)-O-R 4 where R 4 is selected from H, dimethylaminomethyl, dimethylaminoethyl, morpholino, dimethylamino, -CH2-CH2-imidazolidinone, or combinations thereof. In an embodiment, Z 4 is -H, and A 4 contains a heterocyclic ring having one or more nitrogen ring atoms. For example, A 4 can correspond to one of the following formulas: TIFF2025523936000011.tif27170

[0131] The above embodiments are equally applicable to A 4 and Z 4 in the acrylic copolymer of formula (I).

[0132] The weight fraction of the polymerized additional monomer units in the acrylic copolymer can vary depending on factors well known in the art, such as the desired curing time and the desired degree of curing. As described herein, q in formula (I) is the weight fraction of the additional monomer. In an embodiment, q is 0. In other embodiments, q is 0.001 or more, for example 0.005 or more, or 0.01 or more. In an embodiment, q is from 0.001 to 0.20, from 0.001 to 0.10, from 0.001 to 0.05, from 0.001 to 0.03, from 0.005 to 0.20, from 0.005 to 0.10, from 0.005 to 0.05, from 0.005 to 0.03, or from 0.005 to 0.02.

[0133] Preferably, q is from 0 to 0.10.

[0134] The acrylic copolymers described herein can be formed by the controlled polymerization of high Tg monomer units, low Tg monomer units, chromophore monomer units, and optional additional monomers. For forming the acrylic copolymer, general methods known in the art can be used, such as, but not limited to, solution acrylic polymerization.

[0135] [Properties of the Acrylic Copolymer] The acrylic copolymers described herein have different monomer units (i.e., high T g monomer units, low T gIt can be formed by the polymerization of (monomer units, chromophore monomer units, and optionally at least one additional monomer unit). General methods known in the art include, but are not limited to, solution polymerization. Thus, an acrylic copolymer can be obtained by polymerizing different monomer units dissolved in a non-reactive solvent in the presence of an initiator. Solution polymerization can be carried out at a temperature of at least 50 °C, preferably at least 60 °C. Examples of suitable non-reactive solvents include toluene, heptane, ethyl acetate, methyl ethyl ketone (MEK), isopropanol, and combinations thereof. The initiator can be a thermal initiator. Thermal initiators are well-known in the art and include, for example, peroxides (i.e., compounds containing an oxygen-oxygen single bond), particularly inorganic persulfate compounds such as ammonium persulfate, potassium persulfate, and sodium persulfate; hydrogen peroxide; organic peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, acetyl peroxide, benzoyl peroxide, lauroyl peroxide; peracids such as peracetic acid and perbenzoic acid; redox initiators where a reducing agent such as a ferrous compound promotes the decomposition of the peroxide; and azo initiators (i.e., compounds containing a nitrogen-nitrogen double bond), such as other free radical generating substances like 2,2'-azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid) or 2,2'-azobis(2-methylbutyronitrile), and combinations thereof. The initiator can be added in an amount such that the total monomer:initiator weight ratio is from 100:1 to 1000:1. In solution polymerization, typically a mixture of acrylic copolymer dissolved in a non-reactive solvent is obtained. The non-reactive solvent can be removed by heating. A reactive diluent can be added before removing the non-reactive solvent to form a curable composition as detailed below. The mixture at the end of solution polymerization (i.e., before the introduction of the reactive diluent) can have a solids content by weight of 25% to 70%, preferably 30% to 50% based on the total weight of the mixture. The mixture can have a residual monomer amount of less than 2% by weight, particularly less than 1% by weight, more particularly less than 0.5% by weight based on the total weight of the mixture.Using experimental conditions well known to those skilled in the art, the experimental parameters of solution polymerization (i.e., solids content, reaction temperature, reaction time, and total monomer:initiator ratio) can be adjusted to produce a relatively low molecular weight acrylic copolymer.

[0136] Preferably, the acrylic copolymer is not obtained by telomerization, i.e., in the presence of a telogen compound such as carbon tetrabromide (CBr4), bromotrichloromethane (CBrCl3), dibromodichloromethane (CBr2Cl2), mercaptan, hydrogen sulfide, etc. (i.e., a compound having at least one cleavable bond selected from C-H, S-H, P-H, Si-H or C-X where X = Cl, Br or I).

[0137] In an embodiment, the acrylic copolymer may have a weight average molecular weight of at least 10,000 grams per mole (g / mol). In an embodiment, the acrylic copolymer may have a weight average molecular weight from 10,000 g / mol to 600,000 g / mol. In an embodiment, the acrylic copolymer may have a weight average molecular weight of 10,000 g / mol or more, 25,000 g / mol or more, or even 50,000 g / mol or more. In an embodiment, the acrylic copolymer may have a weight average molecular weight of 600,000 g / mol or less, 500,000 g / mol or less, 400,000 g / mol or less, 300,000 g / mol or less, 200,000 g / mol or less, or even 100,000 g / mol or less. In an embodiment, the acrylic copolymer may have a weight average molecular weight from 10,000 g / mol to 600,000 g / mol, from 10,000 g / mol to 500,000 g / mol, from 10,000 g / mol to 400,000 g / mol, from 10,000 g / mol to 300,000 g / mol, from 10,000 g / mol to 200,000 g / mol, from 10,000 g / mol to 100,000 g / mol, from 25,000 g / mol to 600,000 g / mol, from 25,000 g / mol to 500,000 g / mol, from 25,000 g / mol to 400,000 g / mol, from 25,000 g / mol to 300,000 g / mol, from 25,000 g / mol to 200,000 g / mol, from 25,000 g / mol to 100,000 g / mol, from 50,000 g / mol to 600,000 g / mol, from 50,000 g / mol to 500,000 g / mol, from 50,000 g / mol to 400,000 g / mol, from 50,000 g / mol to 300,000 g / mol, from 50,000 g / mol to 200,000 g / mol, or even from 50,000 g / mol to 100,000 g / mol, or may have a weight average molecular weight of all partial ranges formed from any of these endpoints.

[0138] In a preferred embodiment, the acrylic copolymer can have a weight average molecular weight of from 10,000 g / mol to 100,000 g / mol, particularly from 10,000 g / mol to 90,000 g / mol, particularly from 11,000 g / mol to 80,000 g / mol, more particularly from 12,000 g / mol to 75,000 g / mol, even more particularly from 15,000 g / mol to 70,000 g / mol, and still more particularly from 15,000 g / mol to 65,000 g / mol.

[0139] In an embodiment, the acrylic copolymer has a glass transition temperature T of -10 °C or lower in order to ensure that the curable composition is suitable for a predetermined use such as use as a pressure-sensitive adhesive. g In an embodiment, the acrylic copolymer can have a T of -10 °C or lower, for example, -15 °C or lower, -20 °C or lower, -25 °C or lower, or -30 °C or lower. g In an embodiment, the acrylic copolymer can have a T of -120 °C or higher, -100 °C or higher, -80 °C or higher, or even -60 °C or higher. g In an embodiment, the acrylic copolymer has a T formed from any and all partial ranges formed from -10 °C to -120 °C, -10 °C to -100 °C, -10 °C to -80 °C, -10 °C to -60 °C, -15 °C to -120 °C, -15 °C to -100 °C, -15 °C to -80 °C, -15 °C to -60 °C, -20 °C to -120 °C, -20 °C to -100 °C, -20 °C to -80 °C, -20 °C to -60 °C, -25 °C to -120 °C, -25 °C to -100 °C, -25 °C to -80 °C, -25 °C to -60 °C, -30 °C to -120 °C, -30 °C to -100 °C, -30 °C to -80 °C, or even -30 °C to -60 °C, or from any of these endpoints. g In an embodiment, the acrylic copolymer can have a T of -10 °C or lower, for example, -15 °C or lower, -20 °C or lower, -25 °C or lower, or -30 °C or lower.

[0140] In an embodiment, the acrylic copolymer has the formula (V): TIFF2025523936000012.tif182170(wherein m is from 0.2 to 0.8, n is from 0.1 to 0.8, p is from 0.001 to 0.2, and q is from 0 to 0.2).

[0141] In embodiments where q is greater than 0, Z 1 , Z 2 , Z 3 , and Z 4 are independently -H or -CH3. For example, in embodiments where q is greater than 0, Z 1 is -CH3, and Z 2 , Z 3 , and Z 4 are -H. In embodiments where q is equal to 0, Z 1 , Z 2 , and Z 3 are independently -H or -CH3. For example, in embodiments where q is greater than 0, Z 1 is -CH3, and Z 2 and Z 3 are -H. [Curable Composition] In embodiments, the curable composition may include at least one of the acrylic copolymers described herein. In embodiments, the curable composition may not include any additional photoinitiators other than the polymerized chromophore monomer units of the acrylic copolymer. That is, in embodiments, the acrylic copolymer can be cured upon irradiation without an additional photoinitiator. In other embodiments, the curable composition may include one or more photoinitiators in addition to the polymerized chromophore monomer units of the acrylic copolymer. In preferred embodiments, the curable composition may substantially not include photoinitiators other than the acrylic copolymers of the present invention. In particular, the curable composition may include less than 0.1% by weight, particularly less than 0.05% by weight, more particularly less than 0.001% by weight, and even more particularly 0% of photoinitiators other than the acrylic copolymers of the present invention.

[0142] Preferably, the curable composition does not include (meth)acrylic copolymers other than the acrylic copolymers of the present invention.

[0143] In an embodiment, the curable composition may include one or more (meth)acrylate monomers or oligomers, a diluent, a (meth)acrylate oligomer, an amine synergist, a filler, a photoinitiator, an anti-slip agent, a thickener, an anti-slip agent, a hindered amine light stabilizer, an ultraviolet absorbing monomer, or other auxiliary additives.

[0144] In some embodiments, at least one (meth)acrylate oligomer is included, selected from at least one of urethane acrylate and urethane methacrylate, and at least one (meth)acrylate monomer is included, selected from at least one of 2-hydroxyethyl methacrylate and isobornyl methacrylate.

[0145] In a preferred embodiment, the curable composition includes a reactive diluent and the acrylic copolymer according to the present invention. The reactive diluent can be used together with a non-reactive solvent used in the preparation of the acrylic copolymer or can be completely replaced.

[0146] In an embodiment, the reactive diluent may have a viscosity of 3000 cP or less, such as 2750 cP or less, 2500 cP or less, 2250 cP or less, 2000 cP or less, 1750 cP or less, 1500 cP or less, or 1250 or less when measured with a Brookfield DV-III viscometer using spindle SC-27 at 25°C. In an embodiment, the reactive diluent may have a viscosity of 5 cP or more, such as 25 cP or more, 50 cP or more, 100 cP or more, 250 cP or more, 500 cP or more, 750 cP or more, or even 1000 cP or more when measured with a Brookfield DV-III viscometer using spindle SC-27 at 25°C.In an embodiment, the reactive diluent may have a viscosity of from 25 cP to 3000 cP, from 25 cP to 2750 cP, from 25 cP to 2500 cP, from 25 cP to 2250 cP, from 25 cP to 2000 cP, from 25 cP to 1750 cP, from 25 cP to 1500 cP, from 25 cP to 1250 cP, from 25 cP to 3000 cP, from 25 cP to 2750 cP, from 25 cP to 2500 cP, from 25 cP to 2250 cP, from 25 cP to 2000 cP, from 25 cP to 1750 cP, from 25 cP to 1500 cP, from 25 cP to 1250 cP, from 50 cP to 3000 cP, from 50 cP to 2750 cP, from 50 cP to 2500 cP, from 50 cP to 2250 cP, from 50 cP to 2000 cP, from 50 cP to 1750 cP, from 50 cP to 1500 cP, from 50 cP to 1250 cP, from 100 cP to 3000 cP, from 100 cP to 2750 cP, from 100 cP to 2500 cP, from 100 cP to 2250 cP, from 100 cP to 2000 cP, from 100 cP to 1750 cP, from 100 cP to 1500 cP, from 100 cP to 1250 cP, from 250 cP to 3000 cP, from 250 cP to 2750 cP, from 250 cP to 2500 cP, from 250 cP to 2250 cP, from 250 cP to 2000 cP, from 250 cP to 1750 cP, from 250 cP to 1500 cP, from 250 cP to 1250 cP, from 500 cP to 3000 cP, from 500 cP to 2750 cP, from 500 cP to 2500 cP, from 500 cP to 2250 cP, from 500 cP to 2000 cP, from 500 cP to 1750 cP, from 500 cP to 1500 cP, from 500 cP to 1250 cP, from 750 cP to 3000 cP, from 750 cP to 2750 cP, from 750 cP to 2500 cP, from 750 cP to 2250 cP, from 750 cP to 2000 cP, from 750 cP to 1750 cP, from 750 cP to 1500 cP, from 750 cP to 1250 cP, from 1000 cP to 3000 cP, from 1000 cP to 2750 cP, from 1000 cP to 2500 cP, from 1000 cP to 2250 cP, from 1000 cP to 2000 cP, from 1000 cP to 1750 cP, from 1000 cP to 1500 cP, or even from 1000 cP to 1250 cP, or any and all partial ranges formed from any of these endpoints, when measured with a Brookfield DV-III viscometer using a spindle SC-27 at 25°C.

[0147] The reactive diluent may include at least one radically polymerizable diluent. The reactive diluent may include a mixture of radically polymerizable diluents. When the reactive diluent includes a mixture of radically polymerizable diluents, the viscosity-related embodiments apply to the mixture of radically polymerizable diluents.

[0148] As used herein, a radically polymerizable diluent is a compound having at least one polymerizable carbon-carbon double bond and preferably having an appropriate viscosity as defined above. The polymerizable carbon-carbon double bond can participate in free radical polymerization in which at least one of the carbon atoms of the double bond covalently bonds with another atom, particularly a carbon atom, within a second molecule. In particular, the reactive diluent may include at least one radically polymerizable diluent selected from (meth)acrylates, vinyl ethers, vinyl amides, vinyl oxazolidinones, and combinations thereof. These diluents can be monofunctional (i.e., having a single polymerizable carbon-carbon double bond) or polyfunctional (i.e., having at least two polymerizable carbon-carbon double bonds). These diluents can be selected to provide the targeted final properties of the cured formulation as long as they result in an appropriate viscosity reduction of the acrylic copolymer while creating appropriate properties when the curable composition cures.

[0149] The reactive diluent may include monofunctional (meth)acrylates (i.e., monomers having a single (meth)acrylate group). Examples of suitable monofunctional (meth)acrylates include mono(meth)acrylate esters of aliphatic alcohols (where the aliphatic alcohol can be linear, branched or cycloaliphatic and can be a monoalcohol, dialcohol or polyalcohol, provided that only one hydroxyl group is esterified with (meth)acrylic acid); mono(meth)acrylate esters of aromatic alcohols (such as phenols including alkylated phenols); mono(meth)acrylate esters of alkylaryl alcohols (such as benzyl alcohol); mono(meth)acrylate esters of oligomers and polymeric glycols (such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol); mono(meth)acrylate esters of monoalkyl ethers of glycols and oligoglycols; mono(meth)acrylate esters of alkoxylated (e.g., ethoxylated and / or propoxylated) aliphatic alcohols (where the aliphatic alcohol can be linear, branched or cycloaliphatic and can be a monoalcohol, dialcohol or polyalcohol, provided that only one hydroxyl group of the alkoxylated aliphatic alcohol is esterified with (meth)acrylic acid); mono(meth)acrylate esters of alkoxylated (e.g., ethoxylated and / or propoxylated) aromatic alcohols (such as alkoxylated phenols); caprolactone mono(meth)acrylate, etc. are included.The following compounds are specific examples of mono(meth)acrylate-functionalized monomers suitable for use: methyl (meth)acrylate; ethyl (meth)acrylate; n-propyl (meth)acrylate; n-butyl (meth)acrylate; isobutyl (meth)acrylate; n-hexyl (meth)acrylate; 2-ethylhexyl (meth)acrylate; n-octyl (meth)acrylate; isooctyl (meth)acrylate; n-decyl (meth)acrylate; n-dodecyl (meth)acrylate; tridecyl (meth)acrylate; tetradecyl (meth)acrylate; hexadecyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate; 2- and 3-hydroxypropyl (meth)acrylate; 2-methoxyethyl (meth)acrylate; 2-ethoxyethyl (meth)acrylate; 2- and 3-ethoxypropyl (meth)acrylate; tetrahydrofurfuryl (meth)acrylate; alkoxylated tetrahydrofurfuryl (meth)acrylate; 2-(2-ethoxyethoxy)ethyl (meth)acrylate; cyclohexyl (meth)acrylate; glycidyl (meth)acrylate; isodecyl (meth)acrylate; lauryl (meth)acrylate; 2-phenoxyethyl (meth)acrylate; alkoxylated phenol (meth)acrylate; alkoxylated nonylphenol (meth)acrylate; cyclic trimethylolpropane formal (meth)acrylate; isobornyl (meth)acrylate; tricyclodecanemethanol (meth)acrylate; tert-butylcyclohexanol (meth)acrylate; trimethylcyclohexanol (meth)acrylate; diethylene glycol monomethyl ether (meth)acrylate; diethylene glycol monoethyl ether (meth)acrylate; diethylene glycol monobutyl ether (meth)acrylate; triethylene glycol monoethyl ether (meth)acrylate; ethoxylated lauryl (meth)acrylate; methoxypolyethylene glycol (meth)acrylate; hydroxyl ethyl-butyl urethane (meth)acrylate; 3-(2-hydroxyalkyl)oxazolidinone (meth)acrylate; and combinations thereof.

[0150] The reactive diluent may include a monofunctional (meth)acrylate having one or more of the following groups: a ring or ring system (i.e., one or more rings selected from aromatic rings and / or (hetero)alicyclic rings, which may be condensed and / or crosslinked), a C7-C20 hydrocarbon chain (i.e., a straight or branched chain having only carbon and hydrogen atoms, and the number of carbon atoms in the chain is from 7 to 20), one or more oxyalkylene units (such as oxyethylene, oxypropylene, and / or oxybutylene units), one or more ester units derived from the ring-opening of a lactone (such as ε-caprolactone), and combinations thereof. Examples of such monofunctional (meth)acrylates are isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenol (meth)acrylate, nonylphenol (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate; lauryl (meth)acrylate; tridecyl (meth)acrylate, stearyl (meth)acrylate, (poly)caprolactone mono(meth)acrylate, di-, tri-, tetra- or polyethylene glycol mono(meth)acrylate, di-, tri-, tetra- or polyethylene glycol monomethyl ether (meth)acrylate, di-, tri-, tetra- or polyethylene glycol monoethyl ether (meth)acrylate, and their alkoxylated (i.e., ethoxylated and / or propoxylated) derivatives, and combinations thereof.

[0151] The reactive diluent has a T higher than 25 °C, preferably higher than 30 °C, more preferably higher than 35 °C, even more preferably higher than 40 °C, still more preferably higher than 45 °C, and yet more preferably higher than 50 °C gIt may contain a monofunctional (meth)acrylate monomer having. Examples of such monomers include 2-phenylethyl methacrylate, neopentyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, tert-butyl acrylate, octadecyl methacrylate, octadecyl acrylate, glycidyl methacrylate, propyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, ethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2-hydroxypropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2-hydroxyethyl methacrylate, isopropyl methacrylate, isobornyl acrylate, methyl methacrylate, butyl cyanoacrylate, isobornyl methacrylate, phenyl methacrylate, 2-cyanobutyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, 4-tert-butylcyclohexyl methacrylate, ethyl cyanoacrylate, methyl cyanoacrylate, 3,3,5-trimethylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, substituted or unsubstituted (C6-C 12 ) cycloalkyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tricyclodecanemethanol mono(meth)acrylate, 2-phenoxyethyl methacrylate, or combinations thereof.

[0152] Reactive diluents include polyfunctional (meth)acrylates (i.e., monomers having at least two (meth)acrylate groups), such as bisphenol A di(meth)acrylate; hydrogenated bisphenol A di(meth)acrylate; ethylene glycol di(meth)acrylate; diethylene glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol di(meth)acrylate; propylene glycol di(meth)acrylate; dipropylene glycol di(meth)acrylate; tripropylene glycol di(meth)acrylate; tetrapropylene glycol di(meth)acrylate; polypropylene glycol di(meth)acrylate; polytetramethylene glycol di(meth)acrylate; 1,2-butanediol di(meth)acrylate; 2,3-butanediol di(meth)acrylate; 1,3-butanediol di(meth)acrylate; 1,4-butanediol di(meth)acrylate; 1,5-pentanediol di(meth)acrylate; 1,6-hexanediol di(meth)acrylate; 1,8-octanediol di(meth)acrylate; 1,9-nonanediol di(meth)acrylate; 1,10-decanediol di(meth)acrylate; 1,12-dodecanediol di(meth)acrylate; neopentyl glycol di(meth)acrylate; 2-methyl-2,4-pentanediol di(meth)acrylate; polybutadiene di(meth)acrylate; cyclohexane-1,4-dimethanol di(meth)acrylate; tricyclodecane dimethanol di(meth)acrylate; metal di(meth)acrylate; modified metal di(meth)acrylate; glyceryl di(meth)acrylate; glyceryl tri(meth)acrylate; trimethylolethane tri(meth)acrylate; trimethylolethane di(meth)acrylate; trimethylolpropane tri(meth)acrylate; trimethylolpropane di(meth)acrylate; pentaerythritol di(meth)acrylate; pentaerythritol tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; di(trimethylolpropane) diacrylate; di(trimethylolpropane) triacrylate;Di(trimethylolpropane) tetraacrylate, sorbitol penta(meth)acrylate; di(pentaerythritol) tetraacrylate; di(pentaerythritol) pentaacrylate; di(pentaerythritol) hexa(meth)acrylate; tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate; and their alkoxylated (e.g., ethoxylated and / or propoxylated) derivatives; and combinations thereof may be included.;

[0153] The reactive diluent may include vinyl ethers such as dodecyl vinyl ether, hydroxybutyl vinyl ether, cyclohexanedimethanol divinyl ether, and DVE-3 (triethylene glycol divinyl ether) and combinations thereof.

[0154] The reactive diluent may include vinyl amides such as N-vinyl pyrrolidone (NVP), N-vinyl caprolactam (V-CAP) and combinations thereof.

[0155] The reactive diluent may include vinyl oxazolidinones such as vinyl methyl oxazolidinone (VMOX).

[0156] In a preferred embodiment, the reactive diluent preferably includes a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, or a mixture of a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate.

[0157] The amount of the reactive diluent in the curable composition varies according to the desired viscosity. In an embodiment, the curable composition may contain 20% to 80% by weight of the reactive diluent based on the weight of the curable composition. In an embodiment, the curable composition may contain 20% or more, 25% or more, 30% or more, 35% or more, or 40% or more by weight of the reactive diluent based on the weight of the curable composition. In an embodiment, the curable composition may contain 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less by weight of the reactive diluent based on the weight of the curable composition. In an embodiment, the amount by weight of the reactive diluent in the curable composition may be 20% to 80%, 20% to 75%, 20% to 70%, 20% to 75%, 20% to 60%, 25% to 80%, 20% to 75%, 25% to 70%, 25% to 75%, 25% to 60%, 30% to 80%, 30% to 75%, 30% to 70%, 30% to 75%, 30% to 60%, 35% to 80%, 35% to 75%, 35% to 70%, 35% to 75%, 35% to 60%, 40% to 80%, 40% to 75%, 40% to 70%, 40% to 75%, or even 40% to 60%, or any and all partial ranges formed from any of these endpoints based on the total weight of the curable composition.

[0158] In a preferred embodiment, the curable composition may contain at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 40% or at least 50% by weight of the monofunctional (meth)acrylate monomer as defined above based on the total weight of the curable composition. Alternatively, the curable composition may contain less than 5%, less than 4%, less than 3%, less than 2%, less than 1% or 0% by weight of the monofunctional (meth)acrylate monomer as defined above based on the total weight of the curable composition.

[0159] In a preferred embodiment, the curable composition may contain at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 40%, or at least 50% by weight of the polyfunctional (meth)acrylate monomer as defined above, based on the total weight of the curable composition. Alternatively, the curable composition may contain less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, or 0% by weight of the polyfunctional (meth)acrylate monomer as defined above, based on the total weight of the curable composition.

[0160] In an embodiment, the weight ratio of the acrylic copolymer to the reactive diluent in the curable composition may be from 4:1 to 1:4, such as from 3:1 to 1:4, from 2:1 to 1:4, from 1:1 to 1:4, from 3:1 to 1:3, from 2:1 to 1:3, from 1:1 to 1:3, from 3:1 to 1:2, from 2:1 to 1:2, from 1:1 to 1:2, from 3:1 to 1:1, or even from 2:1 to 1:1, or any and all partial ranges formed from any of these endpoints.

[0161] In a preferred embodiment, the curable composition contains the acrylic copolymer according to the present invention and a (meth)acrylate-functionalized oligomer.

[0162] In order to enhance the properties of the cured polymer prepared by curing the curable composition of the present invention, particularly flexibility, strength and / or modulus of elasticity, a (meth)acrylate-functionalized oligomer may be selected.

[0163] The (meth)acrylate-functionalized oligomer may have from 1 to 18 (meth)acrylate groups, particularly from 2 to 6 (meth)acrylate groups, more specifically from 2 to 6 acrylate groups.

[0164] The (meth)acrylate-functionalized oligomer may have a number average molecular weight of 600 g / mol or more, particularly from 800 to 15000 g / mol, more specifically from 1000 to 5000 g / mol.

[0165] In particular, the curable composition may contain a (meth)acrylate-functionalized oligomer selected from the group consisting of epoxy (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, urethane (meth)acrylate, (meth)acrylated poly(meth)acrylate, and mixtures thereof.

[0166] Non-limiting examples of epoxy (meth)acrylates are reaction products of epoxides (such as glycidyl ethers, glycidyl esters, alicyclic epoxides, or epoxides obtained by epoxidation of mono-unsaturated and / or poly-unsaturated compounds) and (meth)acrylating agents (such as (meth)acrylic acid, (meth)acrylic anhydride, (meth)acryloyl chloride, or combinations thereof). Epoxides include EPOX selected from 1,2,3,4-diepoxybutane; 1,2,4,5-diepoxypentane; 1,2,5,6-diepoxyhexane; 1,2,7,8-diepooxyoctane; 1,2,9,10-diepoxydodecane; bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, epoxy novolak resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexanecarboxylate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-1,4-dioxane, bis(3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene oxide, 4-vinyl epoxycyclohexane, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3’,4’-epoxy-6’-methylcyclohexanecarboxylate, methylene bis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di(3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylene bis(3,4-epoxycyclohexanecarboxylate), ethylene glycol diglycidyl ether, 1,2- or 1,3-propylene glycol diglycidyl ether, 1,2-, 1,3- or 1,4-butanediol diglycidyl ether, 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,7-hexanediol diglycidyl ether, 1,8-Octanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 2-methyl-1,3-propanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 2,2-diethyl-1,3-propanediol diglycidyl ether, 3-methyl-1,5-pentanediol diglycidyl ether, 3,3-dimethyl-1,5-pentanediol diglycidyl ether, 2,4-diethyl-1,5-pentanediol diglycidyl ether, 3,3-butylethyl-1,5-pentanediol diglycidyl ether, di-, tri- or tetra(ethylene glycol) diglycidyl ether, di-, tri- or tetra(1,2-propylene glycol) diglycidyl ether, di-, tri- or tetra(1,3-propylene glycol) diglycidyl ether, di-, tri- or tetra(1,4-butylene glycol) diglycidyl ether, poly(ethylene glycol) diglycidyl ether, poly(propylene glycol) diglycidyl ether, poly(trimethylene glycol) diglycidyl ether, poly(tetramethylene glycol) diglycidyl ether, poly(ethylene glycol-co-propylene glycol) diglycidyl ether, glycerol triglycidyl ether, polyglycerol polyglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, di(trimethylolpropane) tetraglycidyl ether, pentaerythritol tetraglycidyl ether, diglycidyl cyclohexanedicarboxylate, cyclohexane diglycidyl ether, cyclohexane-1,Polyethers polyols polyglycidyl ethers obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as 4-dimethylol diglycidyl ether, tricyclodecane dimethanol diglycidyl ether, isosorbide diglycidyl ether, pyrocatechol diglycidyl ether, resorcinol diglycidyl ether, cardol diglycidyl ether, phloroglucinol triglycidyl ether, pyrogallol triglycidyl ether, tris(hydroxyphenyl)methane triglycidyl ether, tris(hydroxyphenyl)ethane triglycidyl ether, diglycidyl phthalate, diglycidyl terephthalate, diglycidyl isophthalate, ethylene glycol, propylene glycol, glycerol, etc.; diglycidyl esters of aliphatic long-chain (C6-C22) dibasic acids; monoglycidyl ethers of aliphatic higher alcohols; monoglycidyl ethers of polyether alcohols obtained by adding alkylene oxides to phenol, cresol, butylphenol, or these compounds; glycidyl esters of higher fatty acids; epoxidized vegetable oils (such as epoxidized soybean oil, epoxidized linseed oil, etc.); epoxidized butyl stearate, epoxidized octyl stearate, epoxidized polybutadiene, triglycidyl isocyanurate, etc. may be used.,

[0167] Non-limiting examples of polyester (meth)acrylate are reaction products of hydroxyl-terminated polyester polyols and (meth)acrylation agents (such as (meth)acrylic acid, (meth)acrylic anhydride, (meth)acryloyl chloride, or combinations thereof). The reaction process may be carried out such that a significant concentration of residual hydroxyl groups remains in the polyester (meth)acrylate, or it may be carried out such that all or substantially all of the hydroxyl groups of the polyester polyol are (meth)acrylated. The polyester polyol can be prepared by polycondensation reaction of a polyhydroxyl-functional component (especially diols) and a polycarboxylic acid-functional compound (especially dicarboxylic acids or anhydrides). To prepare the polyester (meth)acrylate, the hydroxyl groups of the polyester polyol are then partially or completely esterified by reacting with a (meth)acrylation agent. The polyester (meth)acrylate can also be synthesized by reacting a hydroxyl-containing (meth)acrylate such as hydroxyalkyl (meth)acrylate (e.g., hydroxyethyl acrylate) with a polycarboxylic acid. The polyhydroxyl-functional component and the polycarboxylic acid-functional component can each have a linear, branched, alicyclic, or aromatic structure and can be used individually or as a mixture.

[0168] Non-limiting examples of polyether (meth)acrylates are condensation reaction products of a polyetherol, which is a polyether polyol, with a (meth)acrylation agent (e.g., (meth)acrylic acid, (meth)acrylic anhydride, (meth)acryloyl chloride, or combinations thereof). Suitable polyetherols can be linear or branched substances containing ether bonds and terminal hydroxyl groups. Polyetherols can be prepared by ring-opening polymerization of epoxides and other oxygen-containing heterocyclic compounds (e.g., ethylene oxide, 1,2-propylene oxide, butene oxide, tetrahydrofuran, and combinations thereof) with a starter molecule. Suitable starter molecules include water, hydroxyl-functional substances, polyester polyols, and amines. Polyetherols can also be obtained by condensation of diols such as glycols.

[0169] Non-limiting examples of urethane (meth)acrylates are condensation reaction products of at least one polyisocyanate (e.g., diisocyanate, triisocyanate), at least one polyol (e.g., polyether polyol or polyester polyol), and a hydroxyl-functionalized (meth)acrylate (e.g., 2-hydroxyethyl (meth)acrylate or 3-hydroxypropyl (meth)acrylate), which result in terminal (meth)acrylate groups. For example, urethane (meth)acrylates can contain 2, 3, 4, or more (meth)acrylate groups per molecule. The order of addition of the components for preparing urethane (meth)acrylates is well-known in the art. For example, the hydroxyl-functionalized (meth)acrylate can be reacted with the polyisocyanate first to obtain an isocyanate-functionalized (meth)acrylate, which can then be reacted with the polyol. In yet another embodiment, the polyisocyanate can be reacted with the polyol first to obtain an isocyanate-functionalized polyol, which can then be reacted with the hydroxyl-functionalized (meth)acrylate. Alternatively, all the components can be combined and reacted simultaneously.

[0170] (Meta)acrylate-functionalized poly(meth)acrylate is a substance having an oligomeric (meth)acrylic backbone functionalized with one or more (meth)acrylate groups (which may be at the ends of the oligomer or pendant to the acrylic backbone). The (meth)acrylic backbone can be a homopolymer, random copolymer, or block copolymer consisting of repeating units of (meth)acrylic monomers. The (meth)acrylic monomers can be any monomer (meth)acrylate such as C1-C6 alkyl (meth)acrylate, as well as functionalized (meth)acrylates such as (meth)acrylates having hydroxyl, carboxylic acid, and / or epoxy groups. The (meth)acrylate-functionalized poly(meth)acrylate can be prepared using any procedure known in the art, for example, by oligomerizing a (meth)acrylic monomer (e.g., hydroxyalkyl (meth)acrylate, (meth)acrylic acid, glycidyl (meth)acrylate) at least partially functionalized with hydroxyl, carboxylic acid, and / or epoxy groups to obtain a functionalized poly(meth)acrylate, and then reacting this with one or more (meth)acrylate-containing reactants to introduce the desired (meth)acrylate functional groups.

[0171] The curable composition can contain from 0 to 80% by weight, particularly from 5 to 75% by weight, more particularly from 10 to 70% by weight, even more particularly from 15 to 60% by weight, still more particularly from 20 to 50% by weight of the (meth)acrylate-functionalized oligomer, based on the total weight of the curable composition. In particular, the curable composition can contain from 0 to 50% by weight, 1 to 45% by weight, 5 to 40% by weight, 10 to 35% by weight, or 15 to 30% by weight of the (meth)acrylate-functionalized oligomer, based on the total weight of the polymerizable components.

[0172] The curable composition may contain an amine synergist. Some examples of amine synergists include tertiary amines. When an amine synergist-containing monomer is included in an acrylic copolymer together with a Nolish type II chromophore of polymerized chromophore monomer units, the tertiary amine provides an active hydrogen donating site to the excited triplet state of the chromophore, resulting in the generation of a reactive alkylamino radical that can then initiate polymerization. The tertiary amine can also convert non-reactive peroxy species formed by the reaction of oxygen and free radicals into reactive alkylamino radicals, thus reducing the effect of oxygen on curing. Examples of amine synergists that can be components of the polymerized additional monomers include low molecular weight tertiary amines such as triethanolamine, N-methyldiethanolamine (i.e., tertiary amines having a molecular weight of less than 200 g / mol). Other types of amine synergists are aminobenzoates, polymerizable aminobenzoates, polymeric aminobenzoates, and mixtures thereof. Examples of aminobenzoates include ethyl 4-(dimethylamino)benzoate (EDB), pentyl 4-(dimethylamino)benzoate, 2-ethylhexyl 4-(dimethylamino)benzoate, and 2-butoxyethyl 4-(dimethylamino)benzoate (BEDB).

[0173] The curable composition may contain from 0.1 to 10%, particularly 1 to 5%, of an amine synergist based on the weight of the curable composition. Alternatively, the curable composition may substantially not contain an amine synergist (i.e., when the acrylic copolymer contains polymerized additional monomer units that exhibit the above-described synergistic function, such as polymerized additional monomer units containing a tertiary amine functional group). In particular, the curable composition may contain less than 0.1% by weight, particularly less than 0.05% by weight, more particularly less than 0.001% by weight, and even more particularly 0% of an amine synergist other than the acrylic copolymer of the present invention.

[0174] In an embodiment, the curable composition can be liquid at a temperature of 25°C ± 2°C. In an embodiment, when the curable composition is measured with a Brookfield DV-III viscometer using a spindle SC-27 at 60°C, it can have a viscosity of 50,000 cP or less, for example, 45,000 cP or less, 40,000 cP or less, 35,000 cP or less, 30,000 cP or less, 25,000 cP or less, 20,000 cP or less, 15,000 cP or less, 12,500 cP or less, or even 10,000 cP or less. Such viscosity characteristics facilitate spreading the composition on a substrate for film formation.

[0175] In a preferred embodiment, when the curable composition is measured with a Brookfield DV-III viscometer using a spindle SC-27 at 25°C, it can have a viscosity of 50,000 cP or less, for example, 45,000 cP or less, 40,000 cP or less, 35,000 cP or less, 30,000 cP or less, 25,000 cP or less, 20,000 cP or less, 15,000 cP or less, 12,500 cP or less, or 10,000 cP or less.

[0176] In an embodiment, the curable composition can contain less than 1 wt% of a solvent and less than 1 wt% of water, or can be solvent- and water-free. In an embodiment, a film or coating can be formed by curing the curable composition.

[0177] [Method for preparing and curing a curable composition] The present invention also relates to a method for preparing the curable composition according to the present invention. The method for preparing the curable composition includes the following steps: - Preparing an acrylic copolymer according to the present invention dissolved in a non-reactive solvent; - Adding a reactive diluent and diluting to obtain a diluted curable composition; - Removing at least a part of the non-reactive solvent from the diluted curable composition to obtain the curable composition according to the present invention and includes.

[0178] The acrylic copolymer dissolved in a non-reactive solvent can be prepared by solution polymerization as described above. The acrylic copolymer, non-reactive solvent, and reactive diluent can be as defined above. The non-reactive solvent can be at least partially removed by heating the diluted curable composition at a temperature of, for example, 40°C or higher, particularly 50°C or higher, more specifically 60°C or higher. The amount of the non-reactive solvent after the removal step can be less than 1%, less than 0.5%, or even 0% by weight of the non-reactive solvent based on the weight of the curable composition.

[0179] The present invention also relates to a method for curing the curable composition according to the present invention. The method for curing the curable composition includes curing the curable composition.

[0180] The curing step can be carried out at ambient temperature (i.e., 10 to 30°C).

[0181] The curing step can be carried out by irradiating the composition with a light source having a wavelength and / or intensity that can activate the polymerized chromophore monomer units of the acrylic copolymer of the present invention and cause crosslinking of the acrylic copolymer and / or the reactive diluent. The curing step can be carried out in the absence of a photoinitiator other than the acrylic copolymer of the present invention. In other words, the curable composition can contain less than 0.1% by weight, particularly less than 0.05% by weight, more specifically less than 0.001% by weight, and even more specifically 0% by weight of a photoinitiator other than the acrylic copolymer of the present invention based on the weight of the curable composition.

[0182] The method for curing the curable composition of the present invention may not include a pre-curing step, particularly a step of curing at least a part of the reactive diluent by irradiating the curable composition with a long-wavelength and / or low-intensity light source, for example, in the presence of a photoinitiator other than the acrylic copolymer of the present invention, before crosslinking the acrylic copolymer of the present invention. When used herein, the long-wavelength and / or low-intensity light source is a light source that cannot activate the polymerized chromophore monomer units of the acrylic copolymer of the present invention and cannot cause crosslinking of the acrylic copolymer. Examples of long-wavelength and / or low-intensity light sources are black lights (in contrast to LED-UV lamps that can activate chromophores containing thioxanthone moieties). Preferably, the method for curing the curable composition of the present invention includes a curing step of simultaneously curing at least a part of the reactive diluent and at least a part of the acrylic copolymer of the present invention. Without being bound by theory, such a curing method is considered to enable grafting at least a part of the reactive diluent onto at least a part of the oligomer of the present invention.

[0183] [Cured composition] The acrylic copolymer described herein can be cured in combination with a reactive diluent, preferably at least one (meth)acrylate monomer, or at least one (meth)acrylate oligomer, or both, to obtain a cured composition. In an embodiment, the cured composition, which is a product obtained by photocuring a composition comprising the acrylic copolymer according to the embodiment described herein and a reactive diluent, preferably at least one (meth)acrylate monomer, has an initial color of 0.1 to 50 APHA-10mm; an initial yellowness of 0.01 to 2 (b * ); and a T of 0 °C or higher g as shown.

[0184] In some embodiments, the cured composition exhibits an initial color of 0.1 to 50, 0.1 to 45, 0.1 to 40, 0.5 to 45, 1.0 to 45, 2.0 to 40, 3.0 to 40, 4.0 to 40, 5.0 to 40, 7.0 to 40, or 10.0 to 40 APHA-10mm. In other embodiments, the cured composition exhibits an initial color of 0.1 to 10, 0.3 to 9, 0.5 to 9, 1 to 9, 2 to 9, 2.5 to 9, 2.5 to 8, 2.5 to 7.5, or 3 to 7 APHA-10mm.

[0185] In some embodiments, the cured composition has an initial yellowness (b * ) of 0.01 to 2, 0.05 to 2, 0.1 to 2, 0.1 to 1.7, 0.1 to 1.5, 0.2 to 1.5, 0.3 to 1.5, 0.4 to 1.5, 0.4 to 1.4, 0.4 to 1.3, or 0.5 to 1.2. In other embodiments, the cured composition has an initial yellowness (b * ) of 0.01 to 1.0, 0.05 to 1.0, 0.1 to 1.0, 0.1 to 0.7, 0.1 to 0.6, 0.15 to 0.55, or 0.2 to 0.5.

[0186] In embodiments, the cured composition may have a T of 0°C or higher, for example, 5°C or higher, 10°C or higher, 15°C or higher, 20°C or higher, 25°C or higher, 30°C or higher, 35°C or higher, 40°C or higher, 45°C or higher, or 50°C or higher. In embodiments, the cured composition may have a T of from 0°C to 100°C. g g

[0187] In some embodiments, the cured composition does not contain a tertiary amine synergist.

[0188] In embodiments, the cured composition does not contain a small molecule photoinitiator (i.e., a non-polymer photoinitiator).

[0189] In embodiments, the composition is photocured by irradiating the composition with a Phoseon LED 395nm bulb. In other embodiments, the composition is photocured by irradiating the composition with an LC6 Fusion, H bulb.​​

[0190] In some embodiments, at least one (meth)acrylate oligomer is included, selected from at least one of urethane acrylate and urethane methacrylate, and at least one (meth)acrylate monomer is included, selected from at least one of 2-hydroxyethyl methacrylate and isobornyl methacrylate.

[0191] The acrylic copolymers described herein can be incorporated into methods for coating substrates. In an embodiment, the method of coating a substrate is a step of applying a composition to the substrate to form an uncured coating of the composition on the substrate, wherein the composition comprises an acrylic copolymer according to the embodiments described herein and a reactive diluent (preferably at least one (meth)acrylate monomer); and exposing the uncured coating to UV irradiation to cure the composition and obtain a cured coating on the substrate. Exemplary substrates that can be coated include, but are not limited to, glass, polycarbonate, PET, polyethylene, polypropylene, metal, human nails and artificial nails, products including paper, cardboard and paperboard, and ceramics.

[0192] The acrylic copolymers according to the embodiments described herein can be used in graphic arts, inks, and industrial coating applications where yellowing of the acrylic copolymer, the cured composition prepared from the acrylic copolymer, or the coating containing the acrylic copolymer and applied to a substrate is undesirable.

Examples

[0193] The following examples are illustrative in nature and should not be understood as limiting the subject matter of the present disclosure. Using the above embodiments, exemplary reactive acrylic copolymers were prepared and used according to the following examples.

[0194] [Materials] 2-Carboxymethylthioxanthone (CMTX), 4-acryloyloxybenzophenone, methyl ethyl ketone (MEK), butyl acrylate (BA), t-butyl acrylate, glycidyl methacrylate (GMA), methyl methacrylate (MMA), acetic acid, and hydroxyethyl ethylene urea methacrylate were all purchased from Sigma Aldrich Chemical Company. Urethane methacrylate (UMA, CN1968 (registered trademark)), urethane acrylate (UA, CN963 (registered trademark)), hydroxyethyl methacrylate (HEMA, SR170 (registered trademark)) and isobornyl methacrylate (IBOMA, SR423A (registered trademark)), ditrimethylolpropane tetraacrylate (DMPTA, SR355 (registered trademark)), 2-isothioxanthone (ITX, Speedcure ITX (registered trademark)), and 2-ethylhexyl 4-(dimethylamino)benzoate (EHDMA, Speedcure EHA (registered trademark)) are common UV curable monomers and photoinitiators developed by Sartomer.

[0195] [Preparation of Curable Compositions] All curable compositions were prepared by adding the components to a Flacktek® polypropylene cup and mixing them uniformly at 1500 - 2000 rpm for 2 minutes using a Flacktek® DAC400.2 VAC high speed mixer.

[0196] [Test Procedures] To quantify the gel content, the following procedure was used. The sample was pipetted onto a clean glass slide and a 3MIL coating was made using a ByK drawdown square. The drawdown thickness used varied depending on the final percentage of methyl ethyl ketone (MEK) in the reactive acrylic copolymer. For example, when reactive acrylic copolymer 1 (RAC1) was drawn down at a thickness of 4MIL, a 3MIL coating of RAC1 resulted after evaporation of the MEK. After drawdown, the glass slide was placed in an oven at 60 °C for 1 hour to remove the solvent. To cure, the glass slide was passed under an LC6 Fusion H valve curing unit three times at a rate of 15 feet per minute. For the gel content carried out in nitrogen, the glass slide was placed in a nitrogen chamber and filled with nitrogen for 10 minutes, after which the chamber was passed under the H valve for curing. After curing, the crosslinked reactive acrylic copolymer film was removed from the slide glass. Its initial weight was recorded and the removed sample was immersed in MEK for 24 hours. To quantify the final weight of the crosslinked reactive acrylic copolymer, the sample was vacuum filtered from the MEK and placed in an oven at 60 °C to evaporate the excess MEK.

[0197] In the photo differential scanning calorimetry experiment, the following procedure was used. To prepare the sample, the RAC1 and ditrimethylolpropane tetraacrylate (DMPTA, SR355 (registered trademark)) monomers with an initial weight ratio were added to a Flacktek mixing cup and mixed at 2000 RPM for 2 minutes using a Flacktek (registered trademark) DAC400.2 VAC high-speed mixer. A small amount of the sample (5 - 10 mg) was placed in an aluminum Tzero pan, which was then put into an oven at 60 °C for 1 - 2 hours to remove the residual solvent. The initial ratio of RAC1:ditrimethylolpropane tetraacrylate was selected so that the weight ratio of RAC1:ditrimethylolpropane tetraacrylate became 1:1 after the solvent was evaporated. The sample, together with the reference pan, was placed in a TA instruments Q2000 DSC equipped with an EFOS A4000 Acticure UV / visible light curing system containing a 100 W mercury lamp light source. Before the experiment, the UV light intensity was measured from the sample window using an EIT UV power pack II radiometer. During the experiment, the temperature was stable at 25 °C. After 1 minute of equilibration, the UV light (broadband spectrum) was turned on and the heat flow generated from the sample was recorded for 2 minutes. The lamp was turned off and the experiment was run for an additional 1 minute to lower the heat flow to the baseline. The total time of the experiment was 4 minutes.

[0198] For the UV curable coating composition, the following procedure was used. To prepare the UV / LED curable coating composition, the sample was pipetted onto a clean glass slide (4 inches × 4 inches). Using a ByK 3 Mil drawdown bar, the sample was drawn down onto the glass. The coating was placed in an oven at 60 °C for 1 hour to remove MEK. When the MEK had evaporated, all the coatings had a wet thickness of approximately 3 MIL. After drying, the coating was passed through (1) an LC6 Fusion H bulb curing unit three times at 15 feet per minute or (2) a Phoseon LED 395 nm bulb three times at 30 fpm to crosslink the coating composition. Once cured, the initial color, haze, and yellowness were measured using a Hunter Lab ColorQuest XE spectrophotometer. Specifically, color, haze, and yellowness are typically measured on liquid resins using a Hunter Lab colorimeter and on the ASTM D1209 APHA / Pt-Co color scale according to the ASTM D5386 method for the instrument. This method was modified and the modified method was used to measure the color, haze, and yellowness of the coating through the glass. Hunter Lab ColorQuest XE spectrophotometer. Other performance characteristics such as surface tack, König hardness, and adhesion were also measured. The König hardness of the coating formulation was measured using ASTM D4366. Surface tack was determined qualitatively by assigning a numerical value from an arbitrary scale of 0 to 5 (0 is no tack / 5 is very tacky). The adhesion test was measured using ASTM 3359 Method B.

[0199] Example 1 Preparation of PA1 The preparation of photoinitiator adduct 1 (PA1) was accomplished substantially as shown in Scheme I: TIFF2025523936000013.tif36170Briefly speaking, glycidyl methacrylate (GMA), an inhibitor, and a solvent were placed in a round-bottom flask equipped with a stirrer, a thermocouple, a heating mantle, a side arm, and a condenser. The apparatus was heated to 110 °C. While the reaction was being heated, 2-carboxymethoxythioxanthone (CMTX) was slowly added. After the addition of CMTX was complete, air was blown into the mixture and it was heated at 110 °C for 30 minutes to completely dissolve the CMTX. The reaction mixture was cooled to below 50 °C, a catalyst was added, and then it was heated to 85 °C. The reaction mixture was maintained at 85 °C until the reaction was complete as determined by acid value and residual GMA by GC external standard.

[0200] Example 2 Preparation of RAC1 PA1 was further reacted with butyl acrylate (BA) and methyl methacrylate (MMA) in methyl ethyl ketone (MEK) to form reactive acrylic copolymer 1 (RAC1). Table 1 lists the ratios of the components in RAC1, as well as the percentage of the solvent remaining in the final product, predicted T g , and molecular weight.

[0201] The acrylic copolymer was obtained by solution polymerization of the monomers shown in Table 1 using the amount of MEK shown in Table 1 as the solvent. The solvent and monomers were added to a 60 mL vial. A Vazo52 initiator solution in the solvent was prepared in a separate vial and then added to the monomer solution (total monomer:initiator weight ratio was 400:1). Next, the vial was placed in a 65 °C water bath and gently shaken for 11 hours. The type of solvent, solid content, reaction temperature, reaction time, initiator:monomer ratio can be adjusted to produce acrylic copolymers of various molecular weights using experimental conditions well known to those skilled in the art. A monomer:Vazo52 ratio between 100:1 and 1000:1 was typically used to prepare relatively low molecular weight acrylic copolymers as described and used in the following examples. TIFF2025523936000014.tif36170

[0202] Example 3 Curing characteristics of RAC1 Further experiments revealed that RAC1 has low self-reactivity. Specifically, when MEK was evaporated and RAC1 was passed through the Fusion H valve three times at 15 feet per minute in air and nitrogen for curing, RAC1 remained liquid, indicating that three passes were insufficient to photocrosslink the system to form a gel. To obtain a gel-like viscosity, a second attempt was made to cure RAC1 by passing it through the Fusion H valve a total of 10 times at 15 feet per minute. It was found that the gel content of RAC1 was less than 10% (see Tables 2 and 3, entry 1). To increase the curing rate and promote crosslinking, 2-ethylhexyl 4-(dimethylamino)benzoate (EHDMA, Speedcure EHA (registered trademark)) was added to RAC1 at 3%. The gel content of RAC1 + 3% EHDMA remained less than 10%, and the formulation needed to be passed under the lamp 10 times to fully cure (see Tables 2 and 3, entry 2). Finally, ditrimethylolpropane tetraacrylate (DMPTA, SR355 (registered trademark)), a multifunctional monomer, was added to the formulation. With DMPTA, the formulation cured with only 3 passes under Fusion, and the gel content increased regardless of the addition of EHDMA (see Tables 2 and 3, entries 3 and 4). TIFF2025523936000015.tif50170TIFF2025523936000016.tif49170

[0203] The curing rates and reaction enthalpies of RAC1 + 3% EHDMA, 1:1 DMPTA:RAC1, and 1:1 DMPTA:RAC1 + 3% EHDMA were measured (see Table 4). The curing of RAC1 + 3% EHDMA was the slowest. This result is consistent with the low gel content of RAC1. Since the 1:1 DMPTA:RAC1 contains monomers, the curing time was very fast (0.16 minutes). When 3% EHDMA was added to the 1:1 DMPTA:RAC1 formulation, the curing rate was further improved (0.04 minutes). The RAC1-based systems containing DMPTA showed similar exotherms during curing, while RAC1 + 3% EHDMA showed a lower exotherm. TIFF2025523936000017.tif50170From the above results, it is clear that RAC1 can act as a polymer photoinitiator in the presence of other acrylate-functionalized monomers but shows little self-reactivity.

[0204] Example 4 A cured composition containing RAC1 and a (meth)acrylate monomer RAC1 was tested with different curable compositions. Each composition included either urethane methacrylate (UMA, CN1968 (registered trademark)) or urethane acrylate (UA, CN963 (registered trademark)) along with both hydroxyethyl methacrylate (HEMA, SR170 (registered trademark)) and isobornyl methacrylate (IBOMA, SR423A (registered trademark)) at two different weight percentages (11.2% RAC1 or 28% RAC1). The two different weight percentages allowed for chromophore activity amounts of 0.14% or 0.37% considering 30% of MEK in RAC1 that was ultimately removed upon drying, based on RAC1 loaded with 1.7% chromophore in the backbone. The compositions are shown in Table 5 and labeled as Invention Example 1 (I1), Invention Example 2 (I2), Invention Example 3 (I3), and Invention Example 4 (I4). For comparison, a small molecule photoinitiator based on 2 - isothioxanthone (ITX, Speedcure ITX (registered trademark)) with a similar amount of MEK was used with the same monomer mixture. The comparative compositions are shown in Table 5 and labeled as Comparative Example 1 (C1), Comparative Example 2 (C2), Comparative Example 3 (C3), and Comparative Example 4 (C4). TIFF2025523936000018.tif81170

[0205] For each of the curable compositions, two samples were taken. One sample was cured with a Fusion H bulb and the other sample was cured with a Phoseon LED 395 nm. The performance characteristics of the cured compositions are shown in Table 6 (cured with a Fusion H bulb) and Table 7 (cured with a Phoseon LED 395 nm).

[0206] Referring to the compositions cured with the LC6 Fusion H bulb (Table 6), it was shown that the initial color of the photo - cured films of the comparative compositions C1, C2, C3, and C4 exceeded 100 (APHA, 10 mm), while for each of the inventive compositions I1, I2, I3, and I4 it was less than 50. The initial yellowness (b * ) value exceeded 4 for all the comparative compositions, but was less than 1.2 for all the inventive compositions.

[0207] In the compositions cured with Phoseon LED 395 nm (Table 7), it was shown that the initial color of the films after photocuring of Comparative Compositions C1, C2, C3, and C4 exceeded 55 (APHA, 10 mm) as compared with less than 7 for each of Compositions I1, I2, I3, and I4 of the present invention. The initial yellowness (b * ) value exceeded 4 for all Comparative Compositions, but was less than 0.5 for all Compositions of the present invention.

[0208] In both the compositions cured with LC6 Fusion H-valve and the compositions cured with Phoseon LED 395 nm, the haze value after curing was higher for the compositions of the present invention at low concentrations, which is considered to be due to the interaction between the acrylic skeleton and the urethane (meth)acrylate oligomer and may indicate some incompatibility. The haze value was significantly lower for the compositions containing a high concentration of RAC1, which is considered to be because the compatibility with the matrix improves as the concentration increases. At a high concentration of RAC1, the T of the skeleton g was low, so the adhesiveness was improved. In the compositions cured with LC6 Fusion H-valve, the surface tack of the UA formulation was low and the surface hardness was high, indicating a fully crosslinked system. TIFF2025523936000019.tif99170TIFF2025523936000020.tif105170

[0209] To further clarify the reason why the cured compositions containing RAC1 showed significantly less yellowing than the cured compositions containing ITX, further Comparative Compositions were prepared. In particular, curable compositions containing CMTX and PA1 as small molecule photoinitiators were prepared using the same monomer mixture as the above compositions. Chromophore activity amounts of 0.2% or 0.5% were obtained with two different weight percentages. MEK remained in the system until evaporation, as in the compositions of the present invention examined above. The Comparative Compositions are shown in Table 8 and are designated as Comparative Example 5 (C5), Comparative Example 6 (C6), Comparative Example 7 (C7), Comparative Example 8 (C8), Comparative Example 9 (C9), Comparative Example 10 (C10), Comparative Example 11 (C11), and Comparative Example 12 (C12). TIFF2025523936000021.tif82170

[0210] The composition was cured with a Fusion H-valve, and the performance characteristics of the resulting cured composition are shown in Table 9. The initial color of the film after photo-curing all of C5-C12 was again shown to be significantly above 100 (APHA, 10 mm) compared to less than 50 of each composition of the present invention. The initial yellowness (b * ) value exceeded 6 in all comparative compositions compared to less than 1.2 in the compositions of the present invention. Similar to the previous compositions, the surface tack of the UA formulation was low and the surface hardness was high, indicating a fully cross-linked system. TIFF2025523936000022.tif106170

[0211] A further comparative curable composition was prepared containing both small molecule PA1 with a non-reactive acrylic copolymer having the same skeletal components as RAC1 but with no PA1 moiety attached to the skeleton. By testing this control, it can be understood whether the acrylic copolymer skeleton plays a role in low initial yellowing. Comparative compositions prepared with the same monomer mixture as the above compositions are shown in Table 10 and designated as Comparative Example 13 (C13), Comparative Example 14 (C14), Comparative Example 15 (C15), and Comparative Example 16 (C16). TIFF2025523936000023.tif74170

[0212] The curable composition was cured with a Fusion H-valve, and the performance characteristics of the resulting cured composition are shown in Table 11. The performance characteristics of the coating composition containing PA1 with the non-reactive acrylic copolymer are shown in Table 11. The initial color of the film after photo-curing all of C13-C16 was again shown to be significantly above 100 (APHA, 10 mm) compared to less than 50 of each composition of the present invention. The initial yellowness (b * ) value again exceeded 6 in all comparative compositions compared to less than 1.2 in the compositions of the present invention. TIFF2025523936000024.tif80170

[0213] The UMA composition appears to have less initial yellowing compared to the UA composition. This is presumably due to the difference in the polyol skeletons of each urethane (meth)acrylate oligomer. The UMA skeleton has a polyol that is more readily subjected to hydrogen abstraction than the polyol of the UA skeleton. Nevertheless, the initial yellowing is higher at C13 and C15 compared to the composition of the present invention, which indicates that when using RAC1 as a photoinitiator, the yellowing is less than that of the combination of PA1 and the non-reactive acrylic copolymer. Without being bound by theory, it is considered that when the PA1 moiety binds to the skeleton of RAC1, the probability of dimerization of the PA1 moiety, which is the cause of yellowing, decreases.

[0214] [Aspect] A further aspect of the present invention is provided by the subject matter of the following clauses: Clause 1 A high-T monomer having a glass transition temperature (T g ) of 25 °C or higher, a low-T monomer having a T g of less than 25 °C, or a combination of a high-T monomer having a glass transition temperature (T g ) of 25 °C or higher and a low-T monomer having a T g of less than 25 °C; a chromophore monomer containing a moiety selected from thioxanthone, anthraquinone, or camphorquinone; and an acrylic copolymer comprising a reaction product of an optional additional monomer. g ) of 25 °C or higher, a low-T monomer having a T g of less than 25 °C, or a combination of a high-T monomer having a glass transition temperature (T g ) of 25 °C or higher and a low-T monomer having a T g of less than 25 °C; a chromophore monomer containing a moiety selected from thioxanthone, anthraquinone, or camphorquinone; and an acrylic copolymer comprising a reaction product of an optional additional monomer.

[0215] Clause 2 The oligomer has the formula (I): TIFF2025523936000025.tif53170 (wherein, - each A 1 is independently a (C1-C 30 ) hydrocarbyl or a (C1-C 30 ) heterohydrocarbyl, preferably a (C1-C 30 ) hydrocarbyl; - each A 2 is independently a (C4-C 30 ) hydrocarbyl or a (C4-C 30)Heterohydrocarbyl, preferably (C4-C 30 )hydrocarbyl; - Each A 3 is a residue containing a monovalent radical independently selected from thioxanthone, anthraquinone, or camphorquinone, preferably thioxanthone; - Each A 4 is independently (C1-C 30 )hydrocarbyl or (C1-C 30 )heterohydrocarbyl; - Z 1 , Z 2 , Z 3 , and Z 4 are independently -H or (C1-C4)alkyl, preferably -H or -CH3; - m is the weight fraction of high T g monomer units and is from 0 to 0.999; - n is the weight fraction of low T g monomer units and is from 0 to 0.999; - p is the weight fraction of chromophore monomer units and is from 0.001 to 0.4; - q is the weight fraction of additional monomer units and is from 0 to 0.2; - m + n is 0.4 or more; and - m + n + p + q = 1) The acrylic copolymer according to claim 1, having

[0216] Claim 3 m is from 0.001 to 0.999, preferably from 0.01 to 0.50; and n is from 0.001 to 0.999, preferably from 0.50 to 0.98; and m + n is 0.6 or more, The acrylic copolymer according to claim 2.

[0217] Claim 4 Z 1 is methyl, A 1 is methyl, A 2 is n-butyl, The acrylic copolymer according to claim 2 or 3.

[0218] Claim 5 A 3The acrylic copolymer according to any one of claims 2 to 4, which is a monovalent radical containing a thioxanthone moiety.

[0219] Claim 6 A 3 is of formula (IVa) or (IVb): TIFF2025523936000026.tif94170(wherein in formula (IVa) and formula (IVb), L 1 is alkylene; L 2 is a divalent linker containing at least 2 carbon atoms; Each R 1 and R 2 is independently selected from -H, halogen, alkyl, cycloalkyl, heterocycloalkyl, alkoxy, aryloxy, thioalkyl, thioaryl, alkenyl, alkynyl, aryl, aralkyl, alkaryl, heteroaryl, -C(=O)R a -NR b R c alkylamino, alkylthiol, haloalkyl, -NO2, -CN, -C(=O)OR d -C(=O)NR b R c ; R a is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl and optionally substituted aryl; R b R c and R d is independently selected from -H, alkyl and aryl) The acrylic copolymer according to any one of claims 2 to 5, having

[0220] The acrylic copolymer according to any one of claims 2 to 6, wherein q is 0.

[0221] Claim 8 A 1 is methyl, A 2 is n-butyl, A 3is the following formula (IVc) or (IVd): TIFF2025523936000027.tif76170 (where h is from 1 to 20) The acrylic copolymer according to any one of the preceding paragraphs, having

[0222] Item 9 Z 1 is methyl, and Z 2 is -H, and Z 3 is -H, the acrylic copolymer according to any one of the preceding paragraphs.

[0223] Item 10 The acrylic copolymer according to any one of the preceding paragraphs, wherein q is not equal to zero and at least one additional monomer contains at least one amine synergist monomer.

[0224] Item 11 High T g monomer and low T g monomer, and the Fox formula average T of the high T g monomer g is at least 20 °C higher than the Fox formula average T of the low T g monomer g The acrylic copolymer according to any one of the preceding paragraphs.

[0225] Item 12 High T g monomer and low T g monomer, and the difference between the Fox formula average T of the high T g monomer g and the Fox formula average T of the low T g monomer g is from at least 20 °C to 200 °C, the acrylic copolymer according to any one of the preceding paragraphs.

[0226] Item 13 The acrylic copolymer according to any one of the preceding paragraphs, containing at least two different types of high T g monomers.

[0227] Item 14 The acrylic copolymer according to any one of the preceding paragraphs, containing at least two different types of low T g monomers.

[0228] Item 15, high T g monomer and low T g containing monomer, low T in the acrylic copolymer g monomer unit and high T g The acrylic copolymer according to any one of the preceding items, wherein the weight ratio of the monomer unit of low T to the monomer unit of high T is from 10:1 to 1:9.

[0229] Item 16, 2-phenylethyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, tert-butyl acrylate, octadecyl methacrylate, octadecyl acrylate, propyl methacrylate, benzyl methacrylate, isobutyl methacrylate, ethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, isopropyl methacrylate, isobornyl acrylate, methyl methacrylate, isobornyl methacrylate, phenyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, 4-tert-butylcyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, substituted or unsubstituted (C6-C 12 ) cycloalkyl (meth)acrylate, adamantyl (meth)acrylate, tricyclodecanemethanol mono(meth)acrylate, or at least one high T monomer selected from combinations thereof g The acrylic copolymer according to any one of the preceding items, containing the monomer.

[0230] Item 17: At least one low-T monomer selected from n-butyl (meth)acrylate, isobutyl acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate, nonyl acrylate, decyl (meth)acrylate, octyl (meth)acrylate, propyl acrylate, isobutyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, ethyl acrylate, sec-butyl acrylate, dodecyl acrylate, tetradecyl (meth)acrylate, isopropyl acrylate, pentyl (meth)acrylate, benzyl acrylate, cyclohexyl acrylate, hexadecyl (meth)acrylate, 2-methylbutyl acrylate, 2-octyl acrylate, or a combination thereof g The acrylic copolymer according to any one of the preceding items, comprising a monomer.

[0231] Item 18: At least one chromophore monomer represented by formula (IVe) or (IVf) TIFF2025523936000028.tif61170 (where h is from 1 to 10) The acrylic copolymer according to any one of the preceding items, comprising at least one chromophore monomer represented by the above formula.

[0232] Item 19: An acrylic copolymer according to any one of the preceding items, comprising at least one additional monomer unit selected from caprolactone-extended acrylate (SR495B, Sartomer), cyclic trimethylolpropane formal acrylate (SR531, Sartomer), propoxylated tetrahydrofurfuryl acrylate (SR611, Sartomer), beta-carboxyethyl acrylate, glycidyl methacrylate, or 2-(2-ethoxyethoxy)ethyl acrylate (SR256), neopentyl monomethacrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-cyanobutyl acrylate, 4-cyanobutyl acrylate, 2-cyanoethyl acrylate, cyanomethyl acrylate, and combinations thereof.

[0233] Item 20: An acrylic copolymer according to any one of the preceding items, comprising at least one additional monomer selected from (meth)acrylic acid, dimethylaminoethyl acrylate (DMAEA), dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl acrylate (DEAEA), diethylaminoethyl methacrylate (DEAEMA), N-vinylpyrrolidone (NVP), N-vinylcaprolactam (VCAP), acryloxymorpholine (ACMO), dimethylacrylamide (DMAC), poly(ethylene oxide) mono(meth)acrylate, hydroxyethyl ethyleneurea (meth)acrylate (HEEU(M)A), reaction products of cyclic anhydrides with hydroxy-functional (meth)acrylates, and combinations thereof.

[0234] Item 21: An acrylic copolymer according to any one of the preceding items, comprising at least one additional monomer selected from aminobenzoate, polymerizable aminobenzoate, polymeric aminobenzoate, and mixtures thereof.

[0235] Item 22: A glass transition temperature T of -10 °C or lower gThe acrylic copolymer according to any one of the preceding paragraphs, having

[0236] Item 23. A curable composition comprising the acrylic copolymer according to any one of the preceding paragraphs and one or more of the following compounds: (meth)acrylate monomer, diluent, (meth)acrylate oligomer, amine synergist, filler, photoinitiator, slip agent, thickener, slip agent, hindered amine light stabilizer, ultraviolet absorbing monomer, or other auxiliary additives.

[0237] Item 24. The curable composition according to Item 23, comprising a reactive diluent.

[0238] Item 25. The reactive diluent is a monofunctional (meth)acrylate monomer having a Tg higher than 25°C, particularly 2-phenylethyl methacrylate, neopentyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, tert-butyl acrylate, octadecyl methacrylate, octadecyl acrylate, glycidyl methacrylate, propyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, ethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2-hydroxypropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2-hydroxyethyl methacrylate, isopropyl methacrylate, isobornyl acrylate, methyl methacrylate, butyl cyanoacrylate, isobornyl methacrylate, phenyl methacrylate, 2-cyanobutyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, 4-tert-butylcyclohexyl methacrylate, ethyl cyanoacrylate, methyl cyanoacrylate, 3,3,5-trimethylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, substituted or unsubstituted (C6-C 12The curable composition according to item 24, comprising a monofunctional (meth)acrylate monomer selected from cycloalkyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tricyclodecanemethanol mono(meth)acrylate, 2-phenoxyethyl methacrylate, or a combination thereof.

[0239] Item 26. The reactive diluent is a polyfunctional (meth)acrylate, particularly bisphenol A di(meth)acrylate; hydrogenated bisphenol A di(meth)acrylate; ethylene glycol di(meth)acrylate; diethylene glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol di(meth)acrylate; propylene glycol di(meth)acrylate; dipropylene glycol di(meth)acrylate; tripropylene glycol di(meth)acrylate; tetrapropylene glycol di(meth)acrylate; polypropylene glycol di(meth)acrylate; polytetramethylene glycol di(meth)acrylate; 1,2-butanediol di(meth)acrylate; 2,3-butanediol di(meth)acrylate; 1,3-butanediol di(meth)acrylate; 1,4-butanediol di(meth)acrylate; 1,5-pentanediol di(meth)acrylate; 1,6-hexanediol di(meth)acrylate; 1,8-octanediol di(meth)acrylate; 1,9-nonanediol di(meth)acrylate; 1,10-decanediol di(meth)acrylate; 1,12-dodecanediol di(meth)acrylate; neopentyl glycol di(meth)acrylate; 2-methyl-2,4-pentanediol di(meth)acrylate; polybutadiene di(meth)acrylate; cyclohexane-1,4-dimethanol di(meth)acrylate; tricyclodecane dimethanol di(meth)acrylate; metal di(meth)acrylate; modified metal di(meth)acrylate; glyceryl di(meth)acrylate; glyceryl tri(meth)acrylate; trimethylolethane tri(meth)acrylate; trimethylolethane di(meth)acrylate; trimethylolpropane tri(meth)acrylate; trimethylolpropane di(meth)acrylate; pentaerythritol di(meth)acrylate; pentaerythritol tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; di(trimethylolpropane) diacrylate; di(trimethylolpropane) triacrylate;A curable composition according to claim 24 or 25, comprising a polyfunctional (meth)acrylate selected from di(trimethylolpropane) tetraacrylate, sorbitol penta(meth)acrylate; di(pentaerythritol) tetraacrylate; di(pentaerythritol) pentaacrylate; di(pentaerythritol) hexa(meth)acrylate; tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate; and alkoxylated (e.g., ethoxylated and / or propoxylated) derivatives thereof; and combinations thereof.

[0240] Claim 27 A curable composition according to any one of claims 24 to 26, substantially free of a photoinitiator other than the acrylic copolymer according to any one of claims 1 to 22, in particular containing less than 0.1% by weight, in particular less than 0.05% by weight, more particularly less than 0.001% by weight, and even more particularly 0% of a photoinitiator other than the acrylic copolymer according to any one of claims 1 to 22.

[0241] Claim 28 A curable composition according to any one of claims 24 to 27, comprising an amine synergist.

[0242] Claim 28 A curable composition according to any one of claims 24 to 27, substantially free of an amine synergist.

[0243] Claim 29 A cured composition which is a product obtained by photocuring a composition comprising the acrylic copolymer according to any one of claims 1 to 22 and a reactive diluent, preferably at least one (meth)acrylate monomer or at least one (meth)acrylate oligomer, or both, having an initial color of 0.1 to 50 APHA-10mm; an initial yellowness (b * ); and a T of 0 °C or higher g The cured composition shown.

[0244] Claim 30 The cured composition according to claim 29, having an initial color of 0.1 to 40 APHA-10mm.

[0245] Item 31. The cured composition according to item 29 or 30, having an initial yellowness (b * ) of 0.01 to 1.2.

[0246] Item 32. The cured composition according to any one of items 29 to 31, which does not contain a tertiary amine synergist.

[0247] Item 33. The cured composition according to any one of items 29 to 32, which does not contain a small molecule photoinitiator.

[0248] Item 34. The cured composition according to any one of items 29 to 33, which contains at least one (meth)acrylate oligomer selected from at least one of urethane acrylate and urethane methacrylate, and contains at least one (meth)acrylate monomer selected from at least one of 2-hydroxyethyl methacrylate and isobornyl methacrylate.

[0249] Item 35. The cured composition according to any one of items 29 to 34, wherein the acrylic copolymer has a weight average molecular weight of at least 10000 g / mol.

[0250] Item 36. A method for coating a substrate, comprising the step of applying a composition onto the substrate to form an uncured coating of the composition on the substrate, wherein the composition comprises the acrylic copolymer according to any one of items 1 to 22; and a reactive diluent, preferably at least one (meth)acrylate monomer; and the step of exposing the uncured coating to UV radiation to cure the composition to obtain a cured coating on the substrate.

[0251] Item 37. The method according to item 36, wherein the substrate is selected from glass, polycarbonate, PET, polyethylene, polypropylene, metal, human nails and artificial nails, products containing paper, cardboard and thick paper, and ceramics.

[0252] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope disclosed herein. The scope disclosed herein should be construed to include all within the scope of the appended claims and their equivalents, as modifications, combinations, sub - combinations, and variations of the embodiments of the present disclosure that incorporate the spirit and content disclosed herein may occur to those skilled in the art.

[0253] For the purpose of defining the technology, a transitional phrase "consisting of" can be introduced into the claims to make them a closed - ended term that limits the scope of the claims to the recited components or steps and naturally occurring impurities. For the purpose of defining the technology, a transitional phrase "consisting essentially of" can be introduced into the claims to limit the scope of one or more claims to the recited elements, components, materials, or method steps, and unrecited elements, components, materials, or method steps that do not substantially affect the novel characteristics of the claimed subject matter.

[0254] As used in the specification and the appended claims, the singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. The verb "comprises" and its cognate forms should be construed to refer to elements, components, or steps in a non - exclusive manner. The recited elements, components, or steps may be present, utilized, or combined with other elements, components, or steps not explicitly recited.

[0255] Any two quantitative values assigned to a property may constitute the range of that property, and it is necessary to understand that all combinations of ranges formed from all the recited quantitative values of a given property are contemplated in this disclosure. The subject matter disclosed herein has been described in detail with reference to specific embodiments. It is necessary to understand that any detailed description of a component or feature of an embodiment does not necessarily mean that the component or feature is essential to that particular embodiment or other embodiments.

Claims

1. A high-T monomer having a glass transition temperature (T) of 25°C or higher, a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ ), a high-T monomer having a T of less than 25°C, a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ ), a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ ), a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ ), a high-T monomer having a glass transition temperature (T) of 25°C or higher, a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ ), a high-T monomer having a T of less than 25°C, a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ ), a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ ), a low-T monomer having a T of less than 25°C, or a combination of a high-T monomer having a glass transition temperature (T) of 25°C or higher and a low-T monomer having a T of less than 25°C; ｇ a combination of monomers; An acrylic copolymer comprising a reaction product of a chromophore monomer comprising a moiety selected from thioxanthone, anthraquinone, or camphorquinone; and Optionally at least one additional monomer .

2. Formula (I): (In the above formula, - each A １ is independently (C １ - C ３０ ) hydrocarbyl or (C １ - C ３０ ) heterohydrocarbyl, preferably (C １ - C ３０ ) hydrocarbyl; - Each A ２ is independently (C ４ - C ３０ ) hydrocarbyl or (C ４ - C ３０ ) heterohydrocarbyl, preferably (C ４ - C ３０ ) hydrocarbyl; - Each A ３ is a residue containing a monovalent radical independently selected from thioxanthone, anthraquinone, or camphorquinone, preferably thioxanthone; - each A ４ is independently (C １ -C ３０ ) hydrocarbyl or (C １ -C ３０ ) heterohydrocarbyl; -Z １ 、Z ２ 、Z ３ 、and Z ４ is independently -H or (C １ -C ４ ), alkyl, preferably -H or -CH ３ ; - m is the weight fraction of the monomer unit and is from 0 to 0.999; ｇ and is from 0 to 0.999; - n is the weight fraction of monomer units and is from 0 to 0.999; ｇ and is from 0 to 0.999; - p is the weight fraction of the chromophore monomer unit and is from 0.001 to 0.4; - q is the weight fraction of the additional monomer unit and is from 0 to 0.2; - m + n is 0.4 or more; and - m + n + p + q = 1) The acrylic copolymer according to Claim 1, having the same.

3. m is from 0.001 to 0.999, preferably from 0.01 to 0.50; and n is from 0.001 to 0.999, preferably from 0.50 to 0.98; The acrylic copolymer according to Claim 2, wherein m + n is 0.6 or more.

4. Z １ is methyl, and A １ is methyl, and A ２ is n-butyl, the acrylic copolymer according to claim 2 or 3.

5. A ３ The acrylic copolymer according to any one of claims 2 to 4, which is a monovalent radical containing thioxanthone.

6. A ３ is represented by formula (IVa) or (IVb): (Here, in Formula (IVa) and Formula (IVb), L １ is an alkylene; L ２ is a divalent linker containing at least two carbon atoms; Each R １ and R ２ is independently selected from -H, halogen, alkyl, cycloalkyl, heterocycloalkyl, alkoxy, aryloxy, thioalkyl, thioaryl, alkenyl, alkynyl, aryl, aralkyl, alkaryl, heteroaryl, -C(=O)R ａ , -NR ｂ R ｃ , alkylamino, alkylthiol, haloalkyl, -NO ２ , -CN, -C(=O)OR ｄ , -C(=O)NR ｂ R ｃ ; and is independently selected from R ａ is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, and optionally substituted aryl; R ｂ , R ｃ and R ｄ are independently selected from -H, alkyl, and aryl) The acrylic copolymer according to any one of Claims 2 to 5, having the same.

7. The acrylic copolymer according to any one of Claims 2 to 6, wherein q is 0.

8. A curable composition comprising the acrylic copolymer according to any one of Claims 1 to 7 and a reactive diluent.

9. The reactive diluent comprises a monofunctional (meth)acrylate monomer having a Tg higher than 25 °C, in particular, 2-phenylethyl methacrylate, neopentyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, tert-butyl acrylate, octadecyl methacrylate, octadecyl acrylate, glycidyl methacrylate, propyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, ethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2-hydroxypropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2-hydroxyethyl methacrylate, isopropyl methacrylate, isobornyl acrylate, methyl methacrylate, butyl cyanoacrylate, isobornyl methacrylate, phenyl methacrylate, 2-cyanobutyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, 4-tert-butylcyclohexyl methacrylate, ethyl cyanoacrylate, methyl cyanoacrylate, 3,3,5-trimethylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, a substituted or unsubstituted (C ６ -C １２ ) cycloalkyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tricyclodecanemethanol mono(meth)acrylate, 2-phenoxyethyl methacrylate, or a combination thereof, and the curable composition according to claim 8.

10. The reactive diluent is a polyfunctional (meth)acrylate, especially bisphenol A di(meth)acrylate; hydrogenated bisphenol A di(meth)acrylate; ethylene glycol di(meth)acrylate; diethylene glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol di(meth)acrylate; propylene glycol di(meth)acrylate; dipropylene glycol di(meth)acrylate; tripropylene glycol di(meth)acrylate; tetrapropylene glycol di(meth)acrylate; polypropylene glycol di(meth)acrylate; polytetramethylene glycol di(meth)acrylate; 1,2-butanediol di(meth)acrylate; 2,3-butanediol di(meth)acrylate; 1,3-butanediol di(meth)acrylate; 1,4-butanediol di(meth)acrylate; 1,5-pentanediol di(meth)acrylate; 1,6-hexanediol di(meth)acrylate; 1,8-octanediol di(meth)acrylate; 1,9-nonanediol di(meth)acrylate; 1,10-decanediol di(meth)acrylate; 1,12-dodecanediol di(meth)acrylate; neopentyl glycol di(meth)acrylate; 2-methyl-2,4-pentanediol di(meth)acrylate; polybutadiene di(meth)acrylate; cyclohexane-1,4-dimethanol di(meth)acrylate; tricyclodecane dimethanol di(meth)acrylate; metal di(meth)acrylate; modified metal di(meth)acrylate; glyceryl di(meth)acrylate; glyceryl tri(meth)acrylate; trimethylolethane tri(meth)acrylate; trimethylolethane di(meth)acrylate; trimethylolpropane tri(meth)acrylate; trimethylolpropane di(meth)acrylate; pentaerythritol di(meth)acrylate; pentaerythritol tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; di(trimethylolpropane) diacrylate; di(trimethylolpropane) triacrylate;The curable composition according to claim 8 or 9, comprising a polyfunctional (meth)acrylate selected from di(trimethylolpropane) tetraacrylate, sorbitol penta(meth)acrylate; di(pentaerythritol) tetraacrylate; di(pentaerythritol) pentaacrylate; di(pentaerythritol) hexa(meth)acrylate; tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate; and alkoxylated (e.g., ethoxylated and / or propoxylated) derivatives thereof; and combinations thereof.

11. Substantially free of photoinitiators other than the acrylic copolymer according to any one of Claims 1 to 7, in particular, containing less than 0.1% by weight, in particular less than 0.05% by weight, more particularly less than 0.001% by weight, and even more particularly 0% by weight of photoinitiators other than the acrylic copolymer according to any one of Claims 1 to 7, the curable composition according to any one of Claims 8 to 10.

12. A method for preparing the curable composition according to any one of Claims 8 to 11, comprising - A step of preparing by dissolving the acrylic copolymer according to any one of Claims 1 to 7 in a non-reactive solvent; - A step of adding a reactive diluent to obtain a diluted curable composition; - A step of removing at least a part of the non-reactive solvent from the diluted curable composition to obtain a curable composition .

13. A method for curing a curable composition according to any one of claims 8 to 11 or a curable composition prepared by the method according to claim 12, the method comprising irradiating the curable composition with a light source having a wavelength and / or intensity capable of activating the polymerized chromophore monomer units of the acrylic copolymer and causing crosslinking of the acrylic copolymer and / or the reactive diluent to cure the curable composition.

14. An acrylic copolymer according to any one of claims 1 to 7, and a reactive diluent, preferably at least one (meth)acrylate monomer or at least one (meth)acrylate oligomer, or both A cured composition which is a product obtained by photocuring a composition containing an initial color of 0.1 to 50 APHA-10 mm; An initial yellowness (b) of from 0.01 to 2 ＊ ; and T of 0 °C or higher ｇ A cured composition showing

15. The cured composition according to claim 14, showing an initial color of 0.1 to 40 APHA-10 mm.

16. An initial yellowness (b) of from 0.01 to 1.2 ＊ The cured composition according to claim 14 or 15, which exhibits such an initial yellowness (b).

17. The cured composition according to any one of claims 14 to 16, which does not contain a tertiary amine synergist.

18. The cured composition according to any one of claims 14 to 17, which does not contain a small molecule photoinitiator.

19. The cured composition according to any one of claims 14 to 18, wherein at least one (meth)acrylate oligomer is included and is selected from at least one of urethane acrylate and urethane methacrylate, and at least one (meth)acrylate monomer is included and is selected from at least one of 2-hydroxyethyl methacrylate and isobornyl methacrylate.

20. The cured composition according to any one of claims 14 to 19, wherein the acrylic copolymer has a weight average molecular weight of at least 10,000 g / mol.

21. A step of applying a composition to a substrate to form an uncured coating of the composition on the substrate, the composition comprising an acrylic copolymer according to any one of claims 1 to 7; and a reactive diluent, preferably at least one (meth)acrylate monomer A step comprising; A step of exposing the uncured coating to UV radiation to cure the composition and obtain a cured coating on the substrate A method for coating a substrate, comprising

Images