Active energy ray-curable composition

Abstract

An active energy ray-curable composition comprising an inorganic acid, a radical polymerization initiator, a radically polymerizable monomer having a vinyl ether group, and a tertiary aliphatic amine, wherein, when the content of the inorganic acid based on the total amount of the active energy ray-curable composition is defined as X1 mass% and the content of the tertiary aliphatic amine based on the total amount of the active energy ray-curable composition is defined as X2 mass%, X2 / X1 equals 75 or more, and the tertiary aliphatic amine is not an amino alcohol.

Description

Active Energy Ray-Curable Composition

[0001] The present invention relates to an active energy ray-curable composition.

[0002] The active energy ray-curable composition is a composition containing a polymerizable compound, which is used as an ink in a printing apparatus such as an inkjet printer. This composition is used, for example, in a printing method in which it is ejected as an ink onto a recording medium and cured by irradiation with active energy rays.

[0003] In such an active energy ray-curable composition, a polymer having a cationically polymerizable group may be used, or a polymer having both a radically polymerizable group and a cationically polymerizable group may be used. For example, Patent Document 1 discloses a radiation-curable ink containing a monomer having at least one vinyl ether group and at least one (meth)acrylate group. Patent Document 2 discloses a composition containing an acid-polymerizable compound that polymerizes in the presence of an acid. Furthermore, Patent Document 3 discloses an ink composition containing N-vinyllactams and a radically polymerizable compound.

[0004] JP 2019-38256 A, JP 2007-217688 A, JP 2008-31269 A

[0005] In an active energy ray-curable composition containing a radically polymerizable monomer having a vinyl ether group, the stability of the composition is not sufficient, and unintended changes in physical properties may occur when such a composition is stored for a long period of time. In particular, the present inventors have found that inorganic acids may be contained in the composition, originating from raw materials such as polymerizable monomers and radical polymerization initiators used in producing the active energy ray-curable composition. And it has been found that such inorganic acids are related to the stability of the active energy ray-curable composition containing the radically polymerizable monomer having a vinyl ether group, and can affect the stability during long-term storage.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a composition having good stability during long-term storage even when an inorganic acid is contained in an active energy ray-curable composition containing a radical polymerizable monomer having a vinyl ether group as described above.

[0007] As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. The present invention includes the following preferred embodiments. [1] An active energy ray-curable composition comprising an inorganic acid, a radical polymerization initiator, a radical polymerizable monomer having a vinyl ether group, and a tertiary aliphatic amine, wherein the content of the inorganic acid based on the total amount of the active energy ray-curable composition is defined as X １ mass% and the content of the tertiary aliphatic amine is defined as X ２ mass%, X ２ / X １ is 75 or more, and the tertiary aliphatic amine is not an amino alcohol. [2] The active energy ray-curable composition according to [1], wherein the inorganic acid comprises at least one compound selected from the group consisting of sulfonic acid-based compounds and phosphorus-based compounds. [3] The active energy ray-curable composition according to [1] or [2], wherein the inorganic acid is an acid having a pKa of 3 or less. [4] The active energy ray-curable composition according to any one of [1] to [3], wherein the content of the inorganic acid is 0.001 mass% or more based on the total weight of the active energy ray-curable composition. [5] The active energy ray-curable composition according to any one of [1] to [4], wherein the content of the tertiary aliphatic amine is 0.5 to 5 mass% based on the total weight of the active energy ray-curable composition. [6] The active energy ray-curable composition according to any one of [1] to [5], wherein the radical polymerizable monomer having a vinyl ether group is a monomer having at least one vinyl ether group and at least one (meth)acrylate group. [7] The radical polymerizable monomer having a vinyl ether group is represented by formula (I): CH ２ =CR １ -COOR ２ -O-CH=CH-R ３ ... (I) [In formula (I), R １represents a hydrogen atom or a methyl group, R ２ represents a divalent organic group having 2 to 20 carbon atoms, R ３ represents a hydrogen atom or a monovalent organic group having 1 to 11 carbon atoms], the active energy ray-curable composition according to any one of [1] to [6]. [8] The active energy ray-curable composition according to any one of [1] to [7], wherein the radically polymerizable monomer having a vinyl ether group is 2-(2-vinyloxyethoxy)ethyl (meth)acrylate. [9] The active energy ray-curable composition according to any one of [1] to [8], wherein the amount of the radically polymerizable monomer having a vinyl ether group is 30 to 70% by mass based on the total amount of the active energy ray-curable composition.

[10] The active energy ray-curable composition according to any one of [1] to [9], further comprising a polyfunctional (meth)acrylate monomer having 3 or more functional groups.

[11] The active energy ray-curable composition according to

[10] , wherein the amount of the polyfunctional (meth)acrylate monomer having 3 or more functional groups is 15% by mass or less based on the total amount of the active energy ray-curable composition.

[12] The active energy ray-curable composition according to any one of [1] to

[11] , wherein the tertiary aliphatic amine is a tertiary alkyl amine which may have a vinyl group, an acryloyl group, an acryloyloxy group, and / or an alkyl ester group.

[13] The active energy ray-curable composition according to any one of [1] to

[12] , wherein the tertiary aliphatic amine is an alkyl amine, and the alkyl amine contains at least an alkyl group and / or an alkylene group having 4 or more carbon atoms.

[0008] According to the present invention, a composition having good stability during long-term storage can be provided.

[0009] Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications can be made within the range that does not impair the gist of the present invention.

[0010] The active energy ray curable composition of the present invention comprises an inorganic acid, a radical polymerization initiator, a radical polymerizable monomer having a vinyl ether group, and a tertiary aliphatic amine, wherein the content of the inorganic acid based on the total amount of the active energy ray curable composition is X １ The content of the tertiary aliphatic amine is expressed as X in mass percent. ２ When expressed as mass%, X ２ / X １ The value is 75 or higher, and the tertiary aliphatic amine is not an amino alcohol; it is an active energy ray curable composition.

[0011] (Radical polymerizable monomer having a vinyl ether group) The active energy ray curable composition of the present invention contains a radical polymerizable monomer having at least one vinyl ether group. The radical polymerizable monomer having a vinyl ether group contained in the composition may be one type of monomer or a combination of two or more monomers. The monomer is a radical polymerizable monomer that also has a vinyl ether group which is a cationic polymerizable group. When the active energy ray curable composition contains a monomer containing both a radical polymerizable group and a cationic polymerizable vinyl ether group, an ink composition with excellent reactivity and curability can be provided. The radical polymerizable monomer having a vinyl ether group is also referred to as polymerizable monomer (1) in this specification.

[0012] A radical polymerizable monomer having a vinyl ether group is not particularly limited as long as it is a monomer having a vinyl ether group and a radical polymerizable group. Examples of radical polymerizable groups include (meth)acrylate groups and vinyl groups. A radical polymerizable monomer having a vinyl ether group is preferably a monomer having at least one vinyl ether group and at least one (meth)acrylate group.

[0013] Examples of radical polymerizable monomers having a vinyl ether group include formula (I): CH ２ =CR １ - COOR ２ -O-CH=CH-R ３... (I) [In equation (I), R １ R represents a hydrogen atom or a methyl group. ２ R represents a divalent organic group with 2 to 20 carbon atoms. ３ Examples of monomers represented by [where represents a hydrogen atom or a monovalent organic group having 1 to 11 carbon atoms] include monomers represented by formula (I). In this specification, a radical polymerizable monomer having a vinyl ether group represented by formula (I) may be described as polymerizable monomer (I).

[0014] Examples of divalent organic groups having 2 to 20 carbon atoms include alkylene groups having 2 to 20 carbon atoms, cycloalkylene groups having 3 to 20 carbon atoms, and divalent aromatic groups having 6 to 10 carbon atoms.

[0015] The alkylene group having 2 to 20 carbon atoms may be linear or branched. Examples of alkylene groups having 2 to 20 carbon atoms include ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, and hexadecylene. The number of carbon atoms in the alkylene group having 2 to 20 carbon atoms is preferably 2 to 20, more preferably 2 to 15, and even more preferably 2 to 9. At least one -CH group in the alkylene group ２ The - group may be replaced by -O-, -COO-, aromatic groups, etc. In that case, the number of carbon atoms in the replaced group should be between 2 and 20.

[0016] A cycloalkylene group having 3 to 20 carbon atoms is a group containing at least one cyclic structure. Examples of cycloalkylene groups having 3 to 20 carbon atoms include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, cyclononylene, cyclodecylene, cycloundecylene, and cyclohexadecylene. The above cycloalkylene groups may be substituted with one or more alkyl groups having 1 to 3 carbon atoms. The number of carbon atoms in the cycloalkylene group having 3 to 20 carbon atoms is preferably 4 to 15, more preferably 5 to 12. At least one -CH group in the above cycloalkylene group ２The - group may also be replaced with -O-, -COO-, etc. In that case, the number of carbon atoms in the replaced group should be between 3 and 20.

[0017] A divalent aromatic group having 6 to 10 carbon atoms is a group containing at least one aromatic ring. Examples of divalent aromatic groups having 6 to 10 carbon atoms include phenylene groups and naphthylylene groups. The above aromatic groups may be substituted with one or more alkyl groups having 1 to 3 carbon atoms. The number of carbon atoms in the aromatic group having 6 to 10 carbon atoms is preferably 4 to 8, more preferably 5 to 7.

[0018] Examples of monovalent organic groups having 1 to 11 carbon atoms include alkyl groups having 1 to 11 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, and monovalent aromatic groups having 6 to 10 carbon atoms.

[0019] C1-C11 alkyl groups may be linear or branched. Examples of C1-C11 alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. C1-C11 alkyl groups are preferably C1-C3 alkyl groups which may be substituted with phenyl groups, and methyl, ethyl, and benzyl groups are more preferably.

[0020] Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopentane, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. These cycloalkyl groups may be substituted with alkyl groups having 1 to 3 carbon atoms, for example.

[0021] Examples of monovalent aromatic groups having 6 to 10 carbon atoms include phenyl groups and naphthyl groups. These aromatic groups may be substituted with alkyl groups having 1 to 3 carbon atoms, for example.

[0022] As polymerizable monomers represented by formula (I), R １ represents a hydrogen atom or a methyl group, R ２This is an alkylene group having 2 to 20 carbon atoms, or at least one -CH group in an alkylene group having 2 to 20 carbon atoms. ２ - A group in which the - group is replaced by -O- and / or -COO-, R ３ Compounds in which the atom is a hydrogen atom or an alkyl group having 1 to 11 carbon atoms are preferred.

[0023] Examples of polymerizable monomers represented by formula (I) include: • In formula (I), R １ is a hydrogen atom or a methyl group, R ２ R is an alkylene group having 2 to 20 carbon atoms. ３ A polymerizable monomer in which is a hydrogen atom (also called "(meth)acrylate vinyloxyalkyl"), in formula (I), R １ is a hydrogen atom or a methyl group, R ２ R is a cycloalkylene group having 2 to 20 carbon atoms, ３ A polymerizable monomer in which is a hydrogen atom (also called "(meth)acrylate vinyloxycycloalkyl"), in formula (I), R １ is a hydrogen atom or a methyl group, R ２ R is an alkylene group having 2 to 20 carbon atoms. ３ A polymerizable monomer in which is an alkyl group (also called "(meth)acrylate alkylvinyloxyalkyl"), in formula (I), R １ is a hydrogen atom or a methyl group, R ２ These are alkylene groups and cycloalkylene groups having 2 to 20 carbon atoms, R ３ A polymerizable monomer in which is a hydrogen atom (also called "(meth)acrylate vinyloxyalkylcycloalkylalkyl"), in formula (I), R １ is a hydrogen atom or a methyl group, R ２ These are aryl groups and alkylene groups having 2 to 20 carbon atoms, ３ A polymerizable monomer in which is a hydrogen atom (also called "(meth)acrylate vinyloxyalkylarylalkyl"), in formula (I), R １ is a hydrogen atom or a methyl group, R ２ R is an alkoxy group having 2 to 20 carbon atoms and an alkylene group, ３A polymerizable monomer in which is a hydrogen atom (also called "(meth)acrylate vinyloxyalkoxyalkyl"), in formula (I), R １ is a hydrogen atom or a methyl group, R ２ is an alkoxyalkoxy group, R ３ A polymerizable monomer in which is a hydrogen atom (also called "(meth)acrylate vinyloxyalkoxyalkoxyalkyl"), and in formula (I), R １ is a hydrogen atom or a methyl group, R ２ is an alkoxyalkoxyalkoxy group, R ３ Examples include polymerizable monomers in which the atom is a hydrogen atom (also referred to as "(meth)acrylate vinyloxyalkoxyalkoxyalkoxyalkyl"). These polymerizable monomers represented by formula (I) may be used individually or in combination of two or more.

[0024] Examples of vinyloxyalkyl (meth)acrylates include 2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, and 2-vinyloxybutyl (meth)acrylate.

[0025] Examples of vinyloxycycloalkyl (meth)acrylates include vinyloxycyclohexyl (meth)acrylate.

[0026] Examples of alkylvinyloxyalkyl (meth)acrylates include 2-methyl-3-vinyloxypropyl (meth)acrylate and 1-methyl-2-vinyloxypropyl (meth)acrylate.

[0027] Examples of vinyloxyalkylcycloalkylalkyl (meth)acrylates include 3-vinyloxymethylcyclohexylmethyl (meth)acrylate.

[0028] Examples of vinyloxyalkylarylalkyl (meth)acrylates include p-vinyloxymethylphenylmethyl (meth)acrylate.

[0029] Examples of vinyloxyalkoxyalkyl (meth)acrylates include 2-(2-vinyloxyethoxy)ethyl acrylate (VEEA, 2-(2-vinyloxyethoxy)ethyl (meth)acrylate), 2-(2-vinyloxyethoxy)ethyl methacrylate (VEEM), 2-(vinyloxyisopropoxy)propyl (meth)acrylate, and 2-(vinyloxyisopropoxy)isopropyl (meth)acrylate.

[0030] Examples of vinyloxyalkoxyalkyl (meth)acrylates include vinyloxyethoxyethoxyethyl (meth)acrylate.

[0031] Examples of vinyloxyalkoxyalkoxyalkyl (meth)acrylates include vinyloxyethoxyethoxyethoxyethyl (meth)acrylate.

[0032] As the polymerizable monomer represented by formula (I), 2-(2-vinyloxyethoxy)ethyl (meth)acrylate is preferred because it has low viscosity, low odor, minimizes skin irritation, has a high flash point, excellent reactivity and curability, and the coating film formed by curing has excellent adhesion.

[0033] The content of the radical polymerizable monomer having a vinyl ether group is preferably 30 to 70% by mass, more preferably 30 to 50% by mass, and even more preferably 35 to 45% by mass, based on the total amount of the curable composition, from the viewpoint of adjusting the viscosity of the curable composition by acting as a diluent when using a high viscosity monomer as the other polymerizable monomer, as well as from the viewpoint of reactivity and adhesion.

[0034] (Radical polymerizable monomers without vinyl ether groups) The active energy ray curable composition of the present invention may further contain a radical polymerizable monomer without vinyl ether groups in addition to polymerizable monomer (1). The radical polymerizable monomer without vinyl ether groups is also referred to herein as polymerizable monomer (2). Examples of polymerizable monomer (2) include monofunctional polymerizable monomer (2-1) having one radical polymerizable group in one molecule, and polyfunctional polymerizable monomer (2-2) having two or more radical polymerizable groups in one molecule.

[0035] Monofunctional polymerizable monomers (2-1) Monofunctional polymerizable monomers are monomers that have one polymerizable group in one molecule, and examples include acrylamide monomers and monofunctional (meth)acrylic monomers.

[0036] Examples of acrylamide monomers include dimethylacrylamide, diethylacrylamide, 2-hydroxyethylacrylamide, dimethylaminopropylacrylamide, and acryloylmorpholine (ACMO). Among these acrylamide monomers, those having a cyclic structure (more specifically, an alicyclic or heterocyclic structure, etc.) are preferred, and acryloylmorpholine is more preferred.

[0037] Examples of monofunctional (meth)acrylic monomers include monofunctional (meth)acrylic monomers having a chain-like structure or a cyclic structure. Here, monofunctional (meth)acrylic monomers having a chain-like structure do not have a cyclic structure in their molecular structure, but have a linear or branched structure. Monofunctional (meth)acrylic monomers having a cyclic structure have a cyclic structure in their molecular structure and may further have a chain-like structure.

[0038] Monofunctional (meth)acrylic monomers may have a cyclic structure. Examples of monofunctional (meth)acrylic monomers having a cyclic structure include monocyclic alicyclic (meth)acrylates, polycyclic alicyclic (meth)acrylates, and heterocyclic (meth)acrylates. Examples of monocyclic alicyclic (meth)acrylates include cycloalkyl (meth)acrylates (more specifically, 3,3,5-trimethylcyclohexyl acrylate (TMCHA), etc.). Examples of polycyclic alicyclic (meth)acrylates include isobornyl acrylate (IBOA), isobornyl methacrylate, norbornyl (meth)acrylate, amadantyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. Examples of heterocyclic (meth)acrylates include cyclic trimethylolpropane formal acrylate (CTFA). These monofunctional (meth)acrylic monomers may be used individually or in combination of two or more.

[0039] Of these monofunctional (meth)acrylic monomers, at least one selected from the group consisting of isobornyl acrylate (IBOA), 3,3,5-trimethylcyclohexyl acrylate (TMCHA), cyclic trimethylolpropane formal acrylate (CTFA), and isobornyl methacrylate is preferred, and at least one selected from the group consisting of isobornyl acrylate (IBOA), 3,3,5-trimethylcyclohexyl acrylate (TMCHA), and cyclic trimethylolpropane formal acrylate (CTFA) is more preferred.

[0040] In the active energy ray-curable composition of the present invention, from the viewpoint of coating film strength, it is also preferable that the amount of monofunctional polymerizable monomer (2-1) is small or that the monofunctional polymerizable monomer (2-1) is not present. From this viewpoint, the content of monofunctional polymerizable monomer (2-1) may be preferably 10% by mass or less, based on the total amount of the active energy ray-curable composition. When the active energy ray-curable composition contains monofunctional polymerizable monomer (2-1), the content of monofunctional polymerizable monomer (2-1) is preferably 1 to 10% by mass from the viewpoint of coating film strength.

[0041] Polyfunctional polymerizable monomers are monomers having two or more polymerizable groups in one molecule, and examples include polyfunctional (meth)acrylic monomers.

[0042] Examples of polyfunctional (meth)acrylic monomers include difunctional (meth)acrylic monomers, trifunctional (meth)acrylic monomers, tetrafunctional (meth)acrylic monomers, and pentafunctional (meth)acrylic monomers. Polyfunctional (meth)acrylic monomers may have a chain-like structure or an alicyclic structure. Here, polyfunctional (meth)acrylic monomers having a chain-like structure do not have a cyclic structure in their molecular structure and have a linear or branched structure. Polyfunctional (meth)acrylic monomers having an alicyclic structure have an alicyclic structure in their molecular structure and may further have a chain-like structure.

[0043] Examples of difunctional (meth)acrylic monomers having a chain-like structure include alkanediol diacrylates (more specifically, methyl-1,5-pentanediol diacrylate (MPDDA), 1,9-nonanediol diacrylate (1,9ND-A), and 1,10-decanediol diacrylate (DDDA), etc.), polyalkylene glycol diacrylates (more specifically, dipropylene glycol diacrylate (DPGDA), and tripylene glycol diacrylate (TPGDA), etc.), and other diacrylates (more specifically, neopentyl glycol hydroxypivalate diacrylate (HPNDA), and neopentyl glycol propylene oxide diacrylate (NPGPODA), etc.). These polyfunctional (meth)acrylic monomers having a chain-like structure may be used individually or in combination of two or more.

[0044] Examples of bifunctional (meth)acrylic monomers having a cyclic structure include dicyclopentanyl diacrylate (DCPDA).

[0045] Examples of polyfunctional (meth)acrylic monomers with three or more functions include trifunctional (meth)acrylic monomers such as propoxylated trimethylolpropane tri(meth)acrylate, glycerin propoxy tri(meth)acrylate, or pentaerythritol tri(meth)acrylate; tetrafunctional (meth)acrylic monomers such as pentaerythritol tetra(meth)acrylate; pentafunctional (meth)acrylic monomers such as dipentaerythritol hydroxypenta(meth)acrylate; and hexafunctional (meth)acrylic monomers such as dipentaerythritol hexaacrylate (DPHA).

[0046] The content of the polyfunctional (meth)acrylic monomer is preferably 55 to 95% by mass, more preferably 60 to 90% by mass, and even more preferably 65 to 85% by mass, based on the total amount of the curable composition, from the viewpoint of improving the storage stability, discharge stability, and safety of the curable composition, and improving the strength of the coating film. In a preferred embodiment of the present invention, since the curable composition of the present invention has high storage stability, the content of the polyfunctional (meth)acrylic monomer can be relatively high. In that case, the viscosity of the curable composition can be increased and the strength of the coating film can be improved. From the viewpoint of coating film strength and coating film durability, it is preferable that the content of the polyfunctional (meth)acrylic monomer be within the above range.

[0047] The active energy ray curable composition of the present invention preferably contains a difunctional (meth)acrylate monomer from the viewpoint of discharge stability. In this case, the content of the difunctional (meth)acrylate monomer is preferably 30 to 95% by mass, more preferably 40 to 85% by mass, and even more preferably 50 to 80% by mass, based on the total amount of the curable composition.

[0048] From the viewpoint of improving coating strength, the active energy ray curable composition of the present invention preferably contains a trifunctional or polyfunctional (meth)acrylate monomer. In this case, the content of the trifunctional or polyfunctional (meth)acrylate monomer is preferably 1% by mass or more, more preferably 2% by mass or more, based on the total amount of the curable composition. Furthermore, from the viewpoint of discharge stability, the content of the trifunctional or polyfunctional (meth)acrylate monomer is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less. In a more preferred embodiment of the present invention, the content of the trifunctional or polyfunctional (meth)acrylate monomer is preferably 1 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 2 to 7% by mass.

[0049] When the active energy ray curable composition of the present invention contains a radical polymerizable monomer that does not have a vinyl ether group, from the viewpoint of curability, improved coating strength, and storage stability, the content of the radical polymerizable monomer (2) is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and even more preferably 30 to 55% by mass, based on the total amount of the active energy ray curable composition. In a preferred embodiment of the present invention, when the active energy ray curable composition of the present invention contains a polyfunctional monomer, the content of the polyfunctional monomer is preferably 70 to 100% by mass, based on the total amount of the radical polymerizable monomer that does not have a vinyl ether group contained in the active energy ray curable composition. Furthermore, when the active energy ray curable composition of the present invention contains a polyfunctional monomer with three or more functions, the content of the polyfunctional monomer with three or more functions is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, and even more preferably 4 to 15% by mass, based on the total amount of the radical polymerizable monomer that does not have a vinyl ether group contained in the active energy ray curable composition.

[0050] (Inorganic Acids) The active energy ray curable composition of the present invention contains inorganic acids. It has been found that when a curable composition containing a radical polymerizable monomer having a vinyl ether group contains inorganic acids, the reaction between the polymerizable monomer and the inorganic acid results in poor stability during long-term storage. However, the active energy ray curable composition of the present invention maintains good stability during long-term storage even when it contains inorganic acids. The inventors' studies have revealed that the presence of inorganic acids in an active energy ray curable composition, originating from polymerizable compounds or initiators, reduces the stability of the composition during long-term storage. Removing such inorganic acids from polymerizable compounds and initiators used as raw materials requires excessive processes and time. The curable composition of the present invention maintains good stability during long-term storage even when it contains such inorganic acids.

[0051] The inorganic acid is not particularly limited as long as it is an inorganic acid, but examples include sulfone compounds and phosphorus compounds. When the inorganic acid includes at least one compound selected from the group consisting of sulfonic acid compounds and phosphorus compounds, it is particularly preferable when it includes an inorganic acid selected from the group consisting of phenylphosphinic acid, phenylphosphonic acid, methanesulfonic acid, and p-toluenesulfonic acid, in order to maximize the effects of the present invention.

[0052] Examples of sulfone compounds include methanesulfonic acid, p-toluenesulfonic acid, and p-phenolsulfonic acid. Examples of phosphorus compounds include phenylphosphinic acid, phenylphosphonic acid, and diphenylphosphinic acid.

[0053] The inorganic acid content in the active energy ray curable composition of the present invention is preferably 0.001% by mass or more relative to the energy ray curable composition. Preferably, the inorganic acid content selected from the group consisting of phenylphosphinic acid, phenylphosphonic acid, methanesulfonic acid, and p-toluenesulfonic acid is preferably 0.001 to 0.05% by mass, more preferably 0.001 to 0.03% by mass, and even more preferably 0.001 to 0.015% by mass, from the viewpoint of stability during long-term storage and from the viewpoint of maximizing the effects of the present invention. The lower the inorganic acid content, the better.

[0054] Examples of the inorganic acid include acids with a pKa of 3 or less. When the pKa of an inorganic acid is 3 or less, it can be said that the inorganic acid is highly reactive and therefore readily reacts with radical polymerizable monomers having a vinyl ether group. According to the curable composition of the present invention, even when an inorganic acid with a pKa of 3 or less is included, it is possible to improve stability during long-term storage. Therefore, from the viewpoint of maximizing the effects of the present invention, the pKa of the inorganic acid may be 3 or less, for example, 2.5 or less, 2 or less, etc.

[0055] (Tertiary Aliphatic Amine) The active energy ray curable composition of the present invention further comprises a tertiary aliphatic amine. A tertiary aliphatic amine is an amine in which an aliphatic hydrocarbon group, which may have substituents, is bonded to a tertiary nitrogen atom. The number of tertiary nitrogen atoms in a molecule may be one or two or more. Substituents include vinyl groups (CH ２ =CR １ -*), acryloyl group (CH ２ =CR ２ -C(=O)-*), acryloyloxy group (CH ２ =CR ３ -C(=O)-O-*), and alkyl ester group (R ４ -C(=O)-O-*)[R １ ~R ４ Each of these is independently an alkyl group, preferably an alkyl group having 1 to 16 carbon atoms, more preferably an alkyl group having 4 to 16 carbon atoms. However, the tertiary aliphatic amine is not an amino alcohol. The active energy ray curable composition of the present invention may contain one type of tertiary aliphatic amine, or it may contain two or more types of tertiary aliphatic amines.

[0056] Examples of tertiary aliphatic amines include tertiary alkylamines which may have substituents. A tertiary alkylamine is, for example, a compound containing at least one alkyl chain and / or alkylene chain, preferably having 4 or more carbon atoms, more preferably 6 or more, even more preferably 8 or more, and even more preferably 12 or more carbon atoms.

[0057] Examples of tertiary aliphatic amines include ammonia (NH₃). ３ Examples include amines in which three hydrogen atoms are substituted with an alkyl group having 1 to 15 carbon atoms, and groups in which at least one hydrogen atom of the alkyl group of the amine is substituted with a vinyl group, an acryloyl group, an acryloyloxy group, and an alkyl ester group. Specific examples of such tertiary aliphatic amines include tributylamine, trioctylamine, and N,N-dimethyldodecylamine.

[0058] Examples of tertiary aliphatic amines include alkyldiamines (NH3).２ -R ５ -NH ２ ) [R ５ Examples include amines in which four hydrogen atoms of a diamine are substituted with an alkyl group having 1 to 8 carbon atoms, and groups in which at least one hydrogen atom of the alkyl group of the diamine is substituted with a vinyl group, an acryloyl group, an acryloyloxy group, and an alkyl ester group. Specific examples of such tertiary aliphatic amines include tetramethylhexamethylenediamine and tetraethyltetramethylenediamine.

[0059] The tertiary aliphatic amine is preferably an alkylamine, more preferably an alkylamine containing at least an alkyl chain having 4 or more carbon atoms, even more preferably an alkylamine containing at least an alkyl chain having 8 or more carbon atoms, and even more preferably an alkylamine containing at least an alkyl chain having 12 or more carbon atoms.

[0060] From the viewpoint of storage stability of the curable composition, the content of the tertiary aliphatic amine is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, and even more preferably 1 to 5% by mass, based on the total amount of the active energy ray curable composition.

[0061] The content of the inorganic acid based on the total amount of the active energy ray curable composition of the present invention (preferably the content of an inorganic acid selected from the group consisting of phenylphosphinic acid, phenylphosphonic acid, methanesulfonic acid, and p-toluenesulfonic acid) is X １ The content of the tertiary aliphatic amine is expressed as X in mass percent. ２ When expressed as mass%, X ２ / X １ It is 75 or higher. X ２ / X １If the ratio is less than 75, the reaction between the inorganic acid and the radical polymerizable monomer having a vinyl ether group cannot be prevented, resulting in poor stability during long-term storage. Furthermore, it becomes difficult to increase the content of the radical polymerizable monomer having a vinyl ether group in order to ensure stability during long-term storage, and as a result, it becomes difficult to improve the reactivity, curability, and adhesion of the coating film formed by curing of the curable composition.

[0062] From the viewpoint of the stability of the active energy ray curable composition during long-term storage and the ability to flexibly adjust the content of the radical polymerizable monomer having a vinyl ether group according to the purpose, X ２ / X １ Preferably, it is 80 or more, more preferably 90 or more, even more preferably 100 or more, and even more preferably 150 or more.

[0063] (Radical polymerization initiators) In this specification, a radical polymerization initiator is a compound that absorbs active energy rays and initiates a radical polymerization reaction (chain polymerization reaction). Examples of radical polymerization initiators include acylphosphine oxide compounds, alkylphenone compounds, and thioxanthone compounds.

[0064] Examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and ethylphenyl(2,4,6-trimethylbenzoyl)phosphineate. Examples of commercially available acylphosphine oxide compounds include IGM's "Omnirad TPO" (trade name) and "Omnirad 819" (trade name), DKSH's "LUNACURE 900" (trade name), and Arkema's "SPEEDCURE TPO-L" (trade name).

[0065] Examples of alkylphenone compounds include 2,2-dimethoxy-1,2-diphenylethane-1-one and 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one. Commercial alkylphenone compounds include BASF's "Omnirad 651" (trade name) and "Omnirad 907" (trade name).

[0066] Examples of thioxanthone compounds include 2-isopropylthioxanthone, thioxanthone, 2,4-dimethylthioxanthone, 2-chlorothioxanthone, 2-ethylthioxanthone, and 1-chloro-4-propoxythioxanthone.

[0067] From the viewpoint of efficiently advancing the radical polymerization reaction, the content of the radical polymerization initiator is preferably 2 to 20% by mass, more preferably 5 to 15% by mass, and even more preferably 7 to 10% by mass, based on the total amount of the active energy ray curable composition.

[0068] The active energy ray curable composition may use one of the above-mentioned radical polymerization initiators, or two or more may be used in combination. It is preferable to include at least one acylphosphine oxide compound.

[0069] (Oligomer) The active energy ray curable composition of the present invention may further contain a polymerizable oligomer. The polymerizable oligomer may be, for example, one or more prepolymers and / or oligomers of the polymerizable monomers described above. In this specification, a polymerizable oligomer is a polymerizable compound having polymerizable groups and a weight-average molecular weight of 800 or more. In this specification, "oligomer" may be a prepolymer or an oligomer, and encompasses both. The weight-average molecular weight of the polymerizable oligomer is usually 800 or more, and from the viewpoint of curing shrinkage, it is preferably 1,000 or more, more preferably 1,500 or more, and even more preferably 2,000 or more. The upper limit is, for example, 10,000 or less, preferably 5,000 or less. The weight-average molecular weight refers to the weight-average molecular weight in polystyrene terms measured by GPC. The polymerizable oligomer is preferably a polymerizable oligomer that does not have a vinyl ether group, and more preferably an oligomer that does not have a vinyl ether group and has two or more ethylenically unsaturated groups as polymerizable groups.

[0070] Examples of polymerizable oligomers include urethane acrylate oligomers, polyester acrylate oligomers, and epoxy acrylate oligomers. The composition of the present invention may contain one type of polymerizable oligomer, or it may contain a combination of two or more types. The polymerizable oligomer is preferably an ethylenically unsaturated polymerizable oligomer, and more preferably an ethylenically unsaturated polymerizable oligomer having a cyclic structure.

[0071] Examples of urethane acrylate oligomers include reaction products of isocyanate compounds obtained by reacting a polyol with a polyvalent isocyanate and a (meth)acrylate having a hydroxyl group. Examples of isocyanate compounds include diphenylmethane diisocyanate, tolylene diisocyanate, and hydrogenated xylylene diisocyanate, and examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl acrylate. Examples of polyester acrylate oligomers include Arkema's CN2259 and CN293.

[0072] The polymerizable oligomer is preferably an ethylenically unsaturated polymerizable oligomer, and more preferably an ethylenically unsaturated polymerizable oligomer having a cyclic structure. Examples of cyclic structures include aromatic and aliphatic cyclic structures. Examples of such oligomers include oligomers having a bisphenol A skeleton. From the viewpoint of improving the solubility of the polymerization initiator, aromatic ethylenically unsaturated oligomers are preferred.

[0073] If the composition of the present invention contains polymerizable oligomers, the content is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total amount of the curable composition, from the viewpoint of curability and suppression of curing shrinkage. Furthermore, from the viewpoint of suppressing viscosity increase, the content is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on the total amount of the curable composition.

[0074] (Other Components) In addition to the components listed above, the active energy ray curable composition may further contain any other components as needed. Examples of optional components include surfactants (surface tension modifiers), colorants, polymerization inhibitors, dispersants, organic solvents, fixing resins, leveling agents, defoamers, antioxidants, pH adjusters, charge imparters, bactericides, preservatives, deodorants, charge modifiers, wetting agents, and ultraviolet absorbers. These optional components may be used individually or in combination of two or more.

[0075] The surfactant-activated energy ray curable composition may contain at least one surfactant. The surfactant has the effect of adjusting the fluidity of the composition depending on its application. When the activated energy ray curable composition is used, for example, as an ink composition, the wettability of the ink to the recording medium and / or the nozzle substrate of the inkjet head can be adjusted. Examples of surfactants include silicone compounds. As for silicone compounds, for example, silicone compounds having a dimethylsiloxane structure are preferred, and polyether-modified polydimethylsiloxane is more preferred. Examples of commercially available surfactants include BYK-350, 352, 354, 355, 358N, 361N, 381N, 381, 392, BYK-300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 340, 344, 348, 370, 375, 377, 378, 355, 356, 357, 390, UV3500, UV3510, and UV3570 from BYK Chemie, Tegorad-2100, 2200, 2250, 2500, and 2700 from Tego Chemie, and TEGO (registered trademark) from Evonik Degussa. Examples of surfactants include, but are not limited to, "Glide 100, 110, 130, 403, 406, 410, 411, 415, 432, 435, 440, 450, and 482." These surfactants may be used individually or in combination of two or more. From the viewpoint of maintaining good compatibility, it is preferable to use two or more surfactants. By using two or more surfactants in combination, each component maintains good compatibility even when the active energy ray curable composition is stored for a long period of time, so that the active energy ray curable composition can spread sufficiently on the recording medium and maintain the wide color reproducibility that is characteristic of pigments.

[0076] If the active energy ray curable composition contains a surfactant, its content is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, and even more preferably 0.5 to 2% by mass, based on the total amount of the active energy ray curable composition, from the viewpoint of improving the wettability of the composition to recording media and the like.

[0077] Polymerization Inhibitors For the purpose of controlling the progress of the photopolymerization reaction, the active energy ray curable composition may contain polymerization inhibitors. Examples of polymerization inhibitors include hydroquinone compounds, catechol compounds, and phenolic compounds. Examples of hydroquinone compounds include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, tert-butylhydroquinone, and ditert-butylhydroquinone. Examples of catechol compounds include catechol, methylcatechol, and tert-butylcatechol. Examples of phenolic compounds include phenol, 3,5-ditert-butyl-4-hydroxytoluene (butylhydroxytoluene (BHT)), cresol, and methoquinone.

[0078] If the active energy ray curable composition contains a polymerization inhibitor, the amount thereof is preferably 0.05 to 5% by mass, more preferably 0.20 to 2% by mass, and even more preferably 0.1 to 1% by mass, based on the total amount of the active energy ray curable composition, from the viewpoint of achieving both storage stability and curability of the curable composition of the present invention.

[0079] The colorant-curable active energy ray composition may contain a colorant. Examples of colorants include pigments and dyes. From the viewpoint of improving the weather resistance of the formed image, pigments (more specifically, organic pigments and inorganic pigments, etc.) are preferred. A pigment generally refers to a colorant that is poorly soluble in water.

[0080] Examples of black colorants include carbon black. Commercially available black colorants include Toka Black from Tokai Carbon Co., Ltd.; HCF, MCF, RCF, LFF, SCF from Mitsubishi Chemical Corporation; Color Black, Special Black, and Printex from Degussa-Hürss Corporation; Raven from Columbia Chemicals Corporation; and Monarch and Regal from Cabot Corporation.

[0081] Examples of cyan colorants include copper phthalocyanine compounds, anthraquinone compounds, and basic dye lake compounds. Examples of cyan colorants include C.I. Pigment Blue (1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, or 66).

[0082] Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, or arylamide compounds. Examples of yellow colorants include C.I. Pigment Yellow (1, 3, 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 138, 147, 150, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185, 191, 194, and 214). C.I. Pigment Yellow 150 is particularly preferred because it has relatively little absorption around 365-435 nm.

[0083] When the active energy ray curable composition contains a yellow coloring agent, the concentration of the coloring agent is preferably 4.6% by mass or less based on the total amount of the composition. In this case, the absorbance in the UV irradiation area can be reduced and the curability of the adhered coating film can be improved. The lower limit of the content of the yellow coloring agent is not particularly limited and can be adjusted as appropriate according to the desired coloring. The content of the yellow coloring agent is preferably 2.5 to 4.5% by mass, more preferably 3.4 to 4.3% by mass.

[0084] Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolon compounds, thioindigo compounds, or perylene compounds. Examples of magenta colorants include C.I. Pigment Red (2, 3, 5, 6, 7, 19, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 168, 177, 184, 185, 202, 206, 220, 221, or 254).

[0085] Examples of white colorants include white organic pigments (more specifically, pigment white 6, 18, 21, etc.) and white inorganic pigments (more specifically, basic lead carbonate, zinc oxide, titanium oxide, and strontium titanate, etc.).

[0086] From the viewpoint of improving the dispersibility of the pigment in the composition, the average dispersion particle size of the pigment is preferably 20 to 250 nm, and more preferably 50 to 230 nm.

[0087] The coloring agent content is preferably 0.5 to 25% by mass, more preferably 1.0 to 20% by mass, and even more preferably 2.0 to 15% by mass, based on the total amount of the active energy ray curable composition.

[0088] For the purpose of dispersing a colorant in an active energy ray curable composition, the composition of the present invention may contain a dispersant (more specifically, a pigment dispersant, etc.). Examples of dispersants include polyvinyl alcohol, acrylic acid resins, styrene-acrylic acid resins, and vinyl acetate resins. Examples of acrylic acid resins include polyacrylic acid, acrylic acid-acrylonitrile copolymers, and acrylic acid-alkyl acrylate copolymers. Examples of styrene-acrylic acid resins include styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and styrene-acrylic acid-alkyl acrylate copolymers. Examples of vinyl acetate resins include vinyl acetate-ethylene copolymers and vinyl acetate-maleic acid copolymers.

[0089] From the viewpoint of improving the dispersion stability of the active energy ray curable composition, the content of the dispersant is preferably 0.1 to 3% by mass, more preferably 0.5 to 1.5% by mass, relative to the total amount of the active energy ray curable composition.

[0090] The organic solvent-curable active energy ray-curable composition may contain an organic solvent for the purpose of adjusting the viscosity of the composition. From the viewpoint of improving the drying properties of the active energy ray-curable composition, it is preferable that the composition is substantially free of organic solvents. The content of the organic solvent is preferably 0 to 3% by mass or less, more preferably 0 to 1% by mass or less, and even more preferably 0 to 0.5% by mass, based on the total amount of the active energy ray-curable composition. Examples of organic solvents include aromatic hydrocarbons, aliphatic hydrocarbons, ethers, and ketones.

[0091] (Applications) The active energy ray curable composition of the present invention can be used, for example, as an ink composition.

[0092] [Method for preparing an active energy ray-curable composition] An active energy ray-curable composition can be prepared using a conventionally known preparation method. The following describes a preferred preparation method for an active energy ray-curable composition containing a pigment, although the composition may or may not contain a pigment. First, a primary dispersion is prepared by pre-mixing a colorant, a portion of a polymerizable monomer, and any optional components (more specifically, pigment dispersants, etc.) using a disperser, and then dissolving or dispersing each component. Examples of dispersers include a dispa, a container-driven media mill (more specifically, a ball mill, centrifugal mill, and planetary ball mill, etc.), a high-speed rotary mill (more specifically, a sand mill, etc.), and a media stirring mill (more specifically, a stirring tank type mill, etc.).

[0093] Next, the remaining polymerizable monomer, photopolymerization initiator, and, if necessary, surfactants (surface tension modifiers), additives (more specifically, gelation inhibitors, etc.) are added to the obtained primary dispersion and mixed uniformly using a stirrer. Examples of stirrers include dispersers, three-way motors, homogenizers, and magnetic stirrers. In this way, an ink composition can be obtained. Alternatively, the ink composition may be mixed using a mixer such as a line mixer. Furthermore, to further refine the particles in the composition, the active energy ray curable composition may be mixed using a disperser such as a bead mill or a high-pressure jet mill.

[0094] From the viewpoint of discharge stability, the active energy ray curable composition of the present invention preferably has a viscosity of 5 to 30 mPa·s, more preferably 10 to 25 mPa·s, at 25°C. If the viscosity of the active energy ray curable composition exceeds the lower limit mentioned above, when the active energy ray curable composition is used as an ink composition, the ink droplets discharged from the nozzle may become larger, which may reduce the aesthetic appearance of the printed material.

[0095] The active energy ray curable composition of the present invention preferably has an absorbance of 0.6 or less when the composition is diluted 1000 times and placed in a cell with an optical path length of 10 mm, and exposed to light at a wavelength of 365 nm. If the absorbance of the composition exceeds 0.6, the curability of the deposited coating film may decrease. The absorbance of the composition is more preferably 0.55 or less, and even more preferably 0.3 to 0.53.

[0096] The active energy ray curable composition of the present invention preferably has a total absorbance of 105 or less of light at wavelengths of 365 to 435 nm when the composition is diluted 1000 times and placed in a cell with an optical path length of 10 mm. If the total absorbance of the active energy ray curable composition exceeds 100, the curability of the deposited coating film may decrease. The total absorbance of the ink composition is more preferably 90 or less, and even more preferably 40 to 80.

[0097] While there are no particular limitations on the solvent used for dilution when measuring absorbance, polymerizable compounds used in active energy ray curable compositions are preferred, and polymerizable compounds used during pigment dispersion are particularly preferred from the viewpoint of stability during dilution.

[0098] The active energy ray curable composition of the present invention preferably maintains a viscosity of no more than 20% when stored at 60°C for 28 days. If the viscosity change rate of the curable composition exceeds 20%, the dischargeability of the curable composition may deteriorate over time. The viscosity change of the curable composition is preferably 20% or less, more preferably 15% or less, and even more preferably 5 to 11%.

[0099] The above characteristic values ​​of the active energy ray curable composition of the present invention can be adjusted by appropriately changing the type and content of the coloring agent. The coloring agent referred to here is preferably a yellow pigment.

[0100] <Ink Set> An ink set refers to a set of photocurable inkjet recording ink compositions of multiple colors (for example, cyan, magenta, yellow, black, and white) used simultaneously when performing an inkjet recording method. When the active energy ray curable composition of the present invention is used as an ink composition, the inkjet recording ink compositions of each color composed of the composition are combined in an unmixed state. An ink set using the active energy ray curable composition of the present invention as an ink composition is, for example, a combination of cyan, magenta, yellow, and black. In the above case, at least one of each color may be the active energy ray curable composition of the present invention.

[0101] The present invention will be described below based on examples, but the present invention is not limited to these examples.

[0102] First, Tables 1 and 2 show the components used to prepare the active energy ray curable compositions in the following examples and comparative examples.

[0103]

[0104]

[0105] [Example 1] A curable composition 1 was prepared using the components shown in Table 4. Specifically, the components shown in Table 4 were weighed into a 20cc glass bottle and stirred in an ultrasonic cleaner at 45°C for 30 minutes to obtain a curable composition.

[0106] [Examples 2-15 and Comparative Examples 1-6] Curable compositions were prepared in the same manner as in Example 1, except that the components shown in Table 4 or Table 5 were used.

[0107] [Inorganic Acid Content] The inorganic acid content of each material was measured by ion chromatography. For methanesulfonic acid and p-toluenesulfonic acid, each raw material used in the production of the curable compositions in the examples and comparative examples was dissolved in 10 times the amount of ultrapure water, and then heated and extracted at 100°C for 2 hours. The resulting solution was used as the measurement sample. For phenylphosphinic acid and phenylphosphonic acid, 0.1 g of each raw material used in the production of the curable compositions in the examples and comparative examples was weighed in a Teflon® container, 20 mL of ultrapure water was added, the container was sealed tightly, and heated and extracted at 80°C for 2 hours. The extract was processed through a membrane filter (pore size 0.2 μm: PTFE Merck Millipore). The resulting solution was used as the measurement sample. For each measurement sample, the type and amount of inorganic acid contained in each raw material were analyzed using ion chromatography under the following conditions. The inorganic acid content in each composition was calculated from the obtained results and the amount of each raw material blended in each composition. The results are shown in Tables 4 and 5. In this example, the amount of inorganic acid was measured as described above, but the amount of inorganic acid may also be measured by ion chromatography analysis of the obtained curable composition. Alternatively, the amount of inorganic acid may be measured by liquid chromatography instead of ion chromatography, but measurement by ion chromatography is preferred. In this example, inorganic acid was not contained in the raw materials other than those shown in Table 3. (Ion chromatography measurement conditions) The methanesulfonic acid content was measured by anion chromatography. An ICS-1600 (Dionex) instrument was used, and detection was performed using an electrical conductivity detector. The measurement was performed at a temperature of 35°C using an AS12A column (4 mmφ × 200 mm) with a flow rate of 1.5 mL / min, an injection volume of 25 μL, and a 3 mM sodium bicarbonate eluent. The p-toluenesulfonic acid content was measured by anion chromatography. An Integrion RFIC (Thermo Fisher Scientific) instrument was used, and detection was performed using an electrical conductivity detector.At a temperature of 30°C, a column AS20A (4 mmφ × 200 mm) was used with a flow rate of 1.0 mL / min, an injection volume of 25 μL, and a gradient setting (min / potassium hydroxide solution, 0 min / 5 mM → 5 min / 5 mM → 15 min / 30 mL → 20 min / 55 mL), and measurements were performed by continuously changing the mobile phase composition to induce elution. The content of phenylphosphinic acid and phenylphosphonic acid was measured under the same conditions as for p-toluenesulfonic acid. Phenylphosphinic acid and phenylphosphonic acid were detected by an electrical conductivity meter using an ICS-6000 (Thermo Fisher Scientific) instrument. Separation was performed using an IonPac AS11-HC-4 μm (2 mmφ × 250 mm) column with an injection volume of 100 μL and a gradient setting, using potassium hydroxide as the eluent.

[0108] [Viscosity] (Initial Viscosity) The viscosity of the curable compositions obtained in the examples and comparative examples was measured using a Toki Sangyo R100 viscometer (TVE-22L) at a temperature of 25°C and a rotation speed of 20 rpm. (Viscosity after Storage Test) Next, the curable compositions obtained in the examples and comparative examples were stored at 85°C for 3 days. After that, the viscosity of the curable compositions after the storage test was measured in the same manner as the initial viscosity measurement. (Viscosity Change Rate) The initial viscosity was V ０ Pa·s, viscosity after storage test V １ The viscosity change rate was calculated using the following formula, with Pa·s as the viscosity. The results are shown in Tables 3 and 4. Furthermore, the evaluation index was defined as follows: Viscosity change rate [%] = V １ / V ０ ×100 ◎Viscosity change rate of 10% or less 〇Viscosity change rate of more than 10% but 20% or less ×Viscosity change rate of more than 20%

[0109] [Coating Preparation and Evaluation] For coating preparation, ink was applied to a PET film using a bar coater, and the printed film was cured with an LED lamp. The printed film was applied to a thickness of 8 μm using a #3 bar. After application, the irradiation energy was 450 mJ / cm². ２The coating hardened under the specified conditions. The ethanol resistance of the prepared coating was evaluated. The coating was rubbed back and forth 10 times with a cotton swab soaked in an ethanol aqueous solution without any load. The upper limit of the ethanol aqueous solution concentration at which no abrasions occurred on the coating was evaluated. Evaluation ◎ No abrasions occurred with an 80% ethanol aqueous solution. 〇 Abrasions occurred with an 80% ethanol aqueous solution, but not with a 50% ethanol aqueous solution. △ Abrasions occurred with a 50% ethanol aqueous solution, but not with a 10% ethanol aqueous solution. × Abrasions occurred with a 10% ethanol aqueous solution.

[0110]

[0111]

[0112] [Comparison of Thickening Properties by Amine Species] Various amine compounds shown in Table 7 were added to a system containing a radical polymerizable monomer having a vinyl ether group, a radical polymerization initiator, and a polymerization inhibitor, and the storage stability was evaluated. The results obtained are shown in Table 6. In all compositions, the inorganic acid content was 345 μg / g. Furthermore, compositions 6 and 8-12 containing amines e and g-k were found to be compositions of the present invention and were confirmed to be storage stable.

[0113]

[0114]

[0115] [Comparison of Thickening Properties by Acid Type] The acids shown in Table 8 were added to compositions containing radical polymerizable monomers having vinyl ether groups, and storage stability was evaluated in the same manner as above. The results obtained are shown in Table 8.

[0116]

[0117] The results in Table 8 show that when an inorganic acid is present in a radical polymerizable monomer having a vinyl ether group, its stability during long-term storage tends to decrease more easily than when an organic acid is present. However, the active energy ray curable composition of the present invention provides a composition with good stability during long-term storage, as shown in the above examples.

Claims

1. An active energy ray curable composition comprising an inorganic acid, a radical polymerization initiator, a radical polymerizable monomer having a vinyl ether group, and a tertiary aliphatic amine, wherein the content of the inorganic acid based on the total amount of the active energy ray curable composition is X １ The content of the tertiary aliphatic amine is expressed as X in mass percent. ２ When expressed as mass%, X ２ / X １ An active energy ray curable composition in which the tertiary aliphatic amine is 75 or higher, and the tertiary aliphatic amine is not an amino alcohol.

2. The active energy ray curable composition according to claim 1, wherein the inorganic acid comprises at least one compound selected from the group consisting of sulfonic acid compounds and phosphorus compounds.

3. The activated energy ray curable composition according to claim 1 or 2, wherein the inorganic acid is an acid with a pKa of 3 or less.

4. The active energy ray curable composition according to any one of claims 1 to 3, wherein the content of the inorganic acid is 0.001% by mass or more based on the total weight of the active energy ray curable composition.

5. The active energy ray curable composition according to any one of claims 1 to 4, wherein the content of the tertiary aliphatic amine is 0.5 to 5% by mass based on the total weight of the active energy ray curable composition.

6. The active energy ray curable composition according to any one of claims 1 to 5, wherein the radical polymerizable monomer having a vinyl ether group is a monomer having at least one vinyl ether group and at least one (meth)acrylate group.

7. The radical polymerizable monomer having a vinyl ether group is represented by formula (I): CH ２ =CR １ -COOR ２ -O-CH=CH-R ３ ... (I) [In formula (I), R １ represents a hydrogen atom or a methyl group, R ２ represents a divalent organic group having 2 to 20 carbon atoms, R ３ represents a hydrogen atom or a monovalent organic group having 1 to 11 carbon atoms], The active energy ray-curable composition according to any one of claims 1 to 6.

8. The active energy ray curable composition according to any one of claims 1 to 7, wherein the radical polymerizable monomer having a vinyl ether group is 2-(2-vinyloxyethoxy)ethyl (meth)acrylate.

9. The active energy ray curable composition according to any one of claims 1 to 8, wherein the amount of the radical polymerizable monomer having a vinyl ether group is 30 to 70% by mass, based on the total amount of the active energy ray curable composition.

10. The active energy ray curable composition according to any one of claims 1 to 9, further comprising a polyfunctional (meth)acrylate monomer with three or more functions.

11. The active energy ray curable composition according to claim 10, wherein the amount of the three or more polyfunctional (meth)acrylate monomer is 15% by mass or less based on the total amount of the active energy ray curable composition.

12. The active energy ray curable composition according to any one of claims 1 to 11, wherein the tertiary aliphatic amine is a tertiary alkylamine which may have a vinyl group, an acryloyl group, an acryloyloxy group, and / or an alkyl ester group.

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