Photopolymerizable polymer composition, method for producing the same, and polymerization apparatus for carrying out the method.

Abstract

This invention provides a method for producing a photopolymerizable polymer composition with excellent storage stability using low power consumption. [Solution] A polymerizable polymer composition is synthesized by irradiating a monomer composition containing a specific photopolymerization initiator, such as an acetophenone-based polymerization initiator, with visible light having a peak wavelength of 385 nm ± 10 nm, and, in some cases, visible light with different wavelengths ranging from 355 nm to 450 nm, using an LED lamp as the light source.

Description

[Technical Field]

[0001] The present invention relates to a photopolymerizable polymer composition, a method for producing the same, and a polymerization apparatus for carrying out the method, and more particularly to a photopolymerizable polymer composition with little change in viscosity over time, a method for producing such a photopolymerizable polymer composition with low power consumption, and a polymerization apparatus for carrying out such a method. [Background technology]

[0002] Conventionally, adhesives, molding materials, and coatings have been manufactured by bulk polymerization, suspension polymerization, solution polymerization, or emulsion polymerization of monomers such as acrylic monomers. However, in recent years, considering the impact on the environment, polymerizable compositions containing prepolymers are synthesized by bulk polymerization without the use of solvents, and these are used as adhesives or coatings, or further polymerized to produce molded articles (for example, Patent Documents 1 to 3). This polymerizable polymer composition is a viscous liquid composition containing a prepolymer dissolved in monomers, and a cured product is obtained by further polymerization of this composition.

[0003] The primary method for producing polymerizable polymer compositions without using this solvent has conventionally been by thermal polymerization (for example, Patent Documents 1 and 2), but this polymerization method has the problem of a high risk of thermal runaway. Furthermore, since the monomer composition used in this polymerization usually contains a thermal polymerization initiator, the initiator remains in the resulting polymerizable composition, which causes the viscosity of the composition to change over time and eventually gel, resulting in a major problem in terms of storage stability.

[0004] In response to this, methods for producing polymerizable compositions by photopolymerization have been investigated. For example, a method has been proposed in which a polymerizable polymer composition containing prepolymers and oligomers is produced by intermittently irradiating a monomer composition with ultraviolet light using a photopolymerization apparatus equipped with optical fibers as a means of light propagation and a high-pressure mercury lamp as a light source (Patent Documents 3 and 4). However, this apparatus is prone to problems such as a decrease or loss of light transmission capability due to the extremely brittle and easily damaged nature of the optical fibers. In addition, the use of a high-pressure mercury lamp results in very high power consumption per batch. Furthermore, there is also the problem that the concentration of polymers such as prepolymers and oligomers in the polymerizable composition is extremely high, limiting the applications of the composition.

[0005] On the other hand, with the aim of providing an economical hydrocarbon polymerization method, a method has been proposed in which monomers such as acrylic acid and isoprene react with a photopolymerization initiator by passing visible light with a wavelength of 390 nm to 780 nm through a reaction vessel for a predetermined time using an LED light source to obtain polymers (e.g., polyacrylic acid, polyisoprene) (Patent Document 5). However, the wavelength actually selected in this document is only 405 nm, and the same polymerization reaction does not occur with visible light in the entire range of 390 nm to 780 nm. Furthermore, the method described in this document carries out the photopolymerization reaction while the monomer composition is heated using a peroxide-based initiator used as a thermal polymerization initiator, making it unsuitable for the production of polymerizable polymer compositions containing polymerizable components such as prepolymers. In fact, when this method is applied to the production of polymerizable compositions containing polymerizable components such as prepolymers, the viscosity of the composition increases over time, resulting in problems with storage stability. Moreover, since this method performs polymerization under heating conditions, it cannot be said to be a low-energy technology with low CO2 emissions, which is urgently needed in recent years. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Special Publication No. 1-11652 [Patent Document 2] Japanese Patent Application Publication No. 9-67495 [Patent Document 3] Japanese Patent Application Publication No. 07-330815 [Patent Document 4] Japanese Patent Application Publication No. 08-034806 [Patent Document 5] Patent No. 6598770 [Overview of the project] [Problems that the invention aims to solve]

[0007] The first object of the present invention is to provide a method for producing a photopolymerizable polymer composition that has excellent storage stability and can form a cured product with high strength, with low power consumption. The second object of the present invention is to provide a photopolymerizable polymer composition that has a relatively high molecular weight polymer, can form a cured product with high strength, has viscosity that ensures fluidity, and has excellent storage stability. The third object of the present invention is to provide a polymerization apparatus capable of carrying out a method having such excellent advantages. [Means for solving the problem]

[0008] The inventors of the present invention have conducted various studies to address the above-mentioned problems of the present invention and have found that by using an LED lamp as a light source and irradiating a monomer composition containing a specific photopolymerization initiator such as an acetophenone-based polymerization initiator with visible light having a peak wavelength of 385 nm ± 10 nm, and in some cases visible light with different wavelengths in the range of 355 nm to 450 nm, it is possible to produce a photopolymerizable polymer composition that significantly reduces the amount of power required for polymerization, while also being able to form a cured product with a relatively high polymer content and high strength, and exhibiting excellent storage stability with little change in viscosity over time.

[0009] In other words, the present invention provides a method for producing the following photopolymerizable polymer composition, the photopolymerizable polymer composition, a cured product thereof, an article containing the same, and a polymerization apparatus. [1] A step of preparing a monomer composition by mixing a monomer with one or more photopolymerization initiators selected from the group consisting of acetophenone-based polymerization initiators, benzophenone-based polymerization initiators, thioxanthone-based polymerization initiators, and acylphosphine-based polymerization initiators, a chain transfer agent if necessary, and a solvent if necessary. If necessary, the process involves filling the reaction atmosphere with an inert gas, The process involves irradiating the heavy monomer composition with visible light having a peak wavelength of 385 nm ± 10 nm and, optionally, visible light having at least one different peak wavelength in the range of 355 nm to 450 nm from an LED light source while stirring the monomer composition. A method for producing a photopolymerizable polymer composition containing [the specified ingredient]. [2] The manufacturing method according to [1], wherein the monomer composition is irradiated with visible light having a peak wavelength of 385 nm ± 10 nm, visible light having a peak wavelength of 405 ± 10 nm, or visible light having a peak wavelength of 435 nm ± 10 nm. [3] The manufacturing method according to [1], wherein the monomer composition is irradiated with visible light having a peak wavelength of 385 nm ± 10 nm and visible light having a peak wavelength of 435 nm ± 10 nm. [4] The cumulative light intensity is 15,000 mJ / cm². 2 ~300,000 mJ / cm 2 The manufacturing method described in any of [1] to [3]. [5] The method for producing (meth)acrylic acid based on any one of [1] to [4], wherein the monomer is at least one monofunctional or bifunctional or more (meth)acrylic acid based monomer selected from (meth)acrylic acid based monomers esterified with an alkyl alcohol having 1 to 12 carbon atoms, (meth)acrylic acid based esterified with a cycloalkyl alcohol having 6 to 8 carbon atoms, acrylamide monomers, isobornyl (meth)acrylate, and hydroxyalkyl (meth)acrylic acid based monomers having 1 to 5 carbon atoms. [6] The method of production according to any one of [1] to [5], wherein the photopolymerization initiator is one or more photopolymerization initiators selected from the group consisting of acetophenone-based polymerization initiators, benzophenone-based polymerization initiators, and acylphosphine-based polymerization initiators. [7] The chain transfer agent is at least one selected from an α-methylstyrene dimer, a mercaptan compound, and a terpene-based compound, and is the production method according to any one of [1] to [6]. [8] The polymer content contained in the photopolymerizable polymer composition is 20% by mass to 85% by mass, and is the production method according to any one of [1] to [7]. [9] The weight average molecular weight of the polymer in the photopolymerizable polymer composition is 120,000 to 480,000, and the viscosity measured at 25 °C of the photopolymerizable polymer composition is 8,000 mPa·S to 50,000 mPa·S, and is the production method according to any one of [1] to [8].

[10] A photopolymerizable polymer composition produced by the method according to any one of [1] to [9], wherein the monomer is (meth)acrylate ester esterified with an alkyl alcohol having 1 to 12 carbon atoms, (meth)acrylate ester esterified with a cycloalkyl alcohol having 6 to 8 carbon atoms, an acrylamide-based monomer, isobornyl (meth)acrylate, a hydroxyalkyl (meth)acrylate ester having 1 to 5 carbon atoms, and at least one of bifunctional or higher (meth)acrylate esters, and the content of polymers dimer or higher contained in the photopolymerizable polymer composition is 20% by mass to 85% by mass, the weight average molecular weight of the polymer is 120,000 to 480,000, and the viscosity measured at 25 °C is 8,000 mPa·S to 50,000 mPa·S, and is a photopolymerizable polymer composition.

[11] The viscosity change rate before and after holding at 40 °C for 12 months in a dark room is less than 5%, and is the photopolymerizable polymer composition according to

[10] .

[12] A cured product obtained by curing the photopolymerizable polymer composition according to

[10] or

[11] by light irradiation.

[13] An article having the cured product according to

[12] on a substrate made of paper, wood, resin, metal, glass, or metal oxide.

[14] A batch-type photopolymerization apparatus including a reaction vessel having a stirrer, a temperature detector, and a cooler, a gas introduction pipe as needed, and an LED light source capable of controlling irradiation output and irradiation time, The batch photopolymerization apparatus has the LED light source attached outside the reaction vessel, and irradiates the reaction vessel with visible light having a peak wavelength of 385 nm ± 10 nm and, optionally, visible light having at least one different peak wavelength in the range of 355 nm to 450 nm.

[15] The batch photopolymerization apparatus according to

[14] , wherein a condensing lens with a diameter of 3 mm to 10 mm is attached to the light emitting front surface of the light source.

[16] The batch photopolymerization apparatus according to

[14] or

[15] , wherein a plurality of the LED light sources are attached per one reaction vessel, and irradiate the reaction vessel with visible light having a peak wavelength of 385 nm ± 10 nm, visible light having a peak wavelength of 405 nm ± 10 nm, or visible light having a peak wavelength of 435 nm ± 10 nm.

[17] The batch photopolymerization apparatus according to

[14] or

[15] , wherein the LED light source irradiates the reaction vessel with visible light having a peak wavelength of 385 nm ± 10 nm and visible light having a peak wavelength of 435 nm ± 10 nm.

[0010] According to the above manufacturing method, as demonstrated in the examples described later, when the obtained photopolymerizable polymer composition is held in a dark room at 40 °C for 12 months, the viscosity change rate over time before and after that is less than 5%. Further, the power consumption required to produce the photopolymerizable polymer composition is less than 150 kWh / kg, which is the power consumption of one light source per 1 kg of the monomer composition, and in a preferred embodiment, it is less than 105 kWh / kg.

[0011] Here, definitions of the main terms used in this specification are provided. Also, in this specification, the term “(meth)acryl” is used in the sense of including both acrylic and methacrylic. Thus, for example, the term “(meth)acrylic acid” means both or either one of acrylic acid and methacrylic acid. Similarly, the term “(meth)acrylate” means both or either one of acrylate and methacrylate. Furthermore, in this specification, "molecular weight" refers to the weight-average molecular weight, and in this specification, it refers to the value measured by gel permeation chromatography (GPC). Unless otherwise specified, in this specification, "molecular weight" refers to the weight-average molecular weight measured by the GPC method using a SHODEX KF-806M manufactured by Showa Denko Corporation. Furthermore, in this specification, "viscosity" refers to the value measured with a Type B viscometer in accordance with JIS Z 8803. Unless otherwise specified, "viscosity" in this specification means viscosity measured using a Type B viscometer (product name, BMII type viscometer) manufactured by Toki Sangyo Co., Ltd. Furthermore, in this specification, "polymer content" means the content (mass%) of dimers or more of polymers contained in the photopolymerizable polymer composition, and in this specification, it means the mass ratio of the residue obtained by heating the photopolymerizable polymer composition at 150°C for 2 hours to the photopolymerizable composition before heating. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an example of a polymerization apparatus according to one embodiment of the present invention. [Figure 2] This is a schematic diagram showing an example of a light source used in a polymerization apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described in detail. However, the present invention should not be understood as being limited to the following embodiments.

[0014] One embodiment of the present invention relates to a method for producing a photopolymerizable polymer composition by photopolymerization, which involves preparing a monomer composition of a predetermined composition and irradiating the monomer composition with visible light having a predetermined peak wavelength from an LED light source. Another embodiment of the present invention relates to a photopolymerizable polymer composition having predetermined properties obtained by this method, a cured product obtained by curing the same, and an article containing the same. Yet another embodiment of the present invention relates to a batch photopolymerization apparatus that carries out the above method by irradiating a monomer composition in a reaction vessel with visible light having a predetermined peak wavelength from an LED light source. A detailed description follows below.

[0015] 1. Method for producing a photopolymerizable polymer composition The manufacturing method of this embodiment includes the steps of: preparing a monomer composition by mixing a monomer, a predetermined polymerization initiator, a chain transfer agent if necessary, and a solvent if necessary; filling the reaction atmosphere with an inert gas if necessary; and irradiating the monomer composition with visible light of a predetermined peak wavelength from an LED light source while stirring the monomer composition.

[0016] There are no particular restrictions on the monomers, but typically, (meth)acrylic monomers that are often used in the preparation of photopolymerizable polymer compositions can be mentioned. Examples of such (meth)acrylic monomers include monofunctional or bifunctional (meth)acrylic monomers selected from (meth)acrylic acid esters esterified with C1-C12 alkyl alcohols, (meth)acrylic acid esters esterified with C6-C8 cycloalkyl alcohols, acrylamide monomers, isobornyl (meth)acrylates, and C1-C5 hydroxyalkyl (meth)acrylic acid esters. These monomers may be used individually or in combination of two or more.

[0017] Examples of monofunctional monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl acrylate, isononyl acrylate, isooctyl acrylate, lauryl acrylate, benzyl (meth)acrylate, decyl acrylate, cyclohexyl (meth)acrylate, dimethylacrylamide, diethylacrylamide, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, isobornyl (meth)acrylate, and the like.

[0018] Examples of bifunctional monomers include propylene glycol di(meth)acrylate and trimethylolpropane tri(meth)acrylate.

[0019] Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polytetraethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, nonanediol di(meth)acrylate, decanediol di(meth)acrylate, dodecanediol di(meth)acrylate, and the like. Polyfunctional monomers may be included in a range that does not gel during polymerization, and their content is preferably less than 5% by mass.

[0020] Alternatively, the monomer composition may contain only monofunctional monomers as monomer components, and a photopolymerizable polymer composition after photopolymerization may be mixed with bifunctional or more functional monomers.

[0021] In the manufacturing method of this embodiment, peroxide-based photopolymerization initiators such as hydrogen peroxide, benzoyl peroxide, t-butyl hydroperoxide, and perbenzoic acid are not used as photopolymerization initiators, from the viewpoint of improving the storage stability of the photopolymerizable polymer composition obtained after polymerization. Examples of photopolymerization initiators used include at least one selected from the group consisting of acetophenone-based polymerization initiators, benzophenone-based polymerization initiators, alkylphenone-based polymerization initiators, thioxanthone-based polymerization initiators, xanthone-based photopolymerization initiators, acylphosphine-based polymerization initiators, oxime-based polymerization initiators, benzoin compound-based polymerization initiators, anthracene compound-based polymerization initiators, and quinone compound-based polymerization initiators. In terms of solubility and polymerization initiation efficiency, at least one photopolymerization initiator selected from the group consisting of acetophenone-based polymerization initiators, benzophenone-based polymerization initiators, thioxanthone-based polymerization initiators, and acylphosphine-based polymerization initiators is preferred, and at least one photopolymerization initiator selected from the group consisting of acetophenone-based polymerization initiators, benzophenone-based polymerization initiators, and acylphosphine-based polymerization initiators is more preferred. Among these, the combination of an acetophenone-based polymerization initiator and an acylphosphine-based polymerization initiator is particularly preferred.

[0022] Examples of acetophenone-based photopolymerization initiators include α-aminoacetophenone-based photopolymerization initiators such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, as well as 1-hydroxy-cyclohexyl-phenyl- Examples of α-hydroxyacetophenone-based photopolymerization initiators include ketones, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl]-2-methyl-propan-1-one, which may be used alone or in combination of two or more. Among these, α-hydroxyacetophenone-based photopolymerization initiators are preferred.

[0023] Examples of benzophenone-based polymerization initiators include benzophenone, 4-methylbenzophenone, o-benzoyl methyl-4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylic benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, and 2,4-dihydrobenzophenone. Examples include xybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-propoxybenzophenone, benzophenone, o-methyl benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, and 4,4'-di(N,N'-dimethylamino)-benzophenone, which may be used alone or in combination of two or more. Among these, benzophenone is preferred.

[0024] Examples of alkylphenone compound polymerization initiators include benzyl methyl ketal compounds such as 2,2'-dimethoxy-1,2-diphenylethane-1-one, α-hydroxyalkylphenone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, as well as aminoalkylphenone compounds such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one and 2-benzylmethyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone. These may be used alone or in combination of two or more.

[0025] Examples of thioxanthone-based photopolymerization initiators include thioxanthone, dimethylthioxanthone (e.g., 2,4-dimethylthioxanthone), diethylthioxanthone (e.g., 2,4-diethylthioxanthone), isopropylthioxanthone (e.g., 2-isopropylthioxanthone), chlorothioxanthone (e.g., 2,4-dichlorothioxanthone, mercaptothioxanthone), and the like. Examples of xanthone-based photopolymerization initiators include xanthone, 2-isopropylxanthone, 2,4-dimethylxanthone, 2,4-diethylxanthone, and 2,4-dichloroxanthone, which may be used alone or in combination of two or more.

[0026] Examples of acylphosphine-based photopolymerization initiators include bisacylphosphine oxide-based photopolymerization initiators and monoacylphosphine oxide-based photopolymerization initiators. Specifically, examples include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide. Examples include fin oxides, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine methyl ester, 2-methylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphine ester, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl-2,4,6-trimethylbenzoylphenylphosphenate, (2,6-dimethoxybenzoyl)-2,4,4-pentylphosphine oxide, etc., which may be used alone or in combination of two or more. Monoacylphosphine oxide-based photopolymerization initiators such as ethyl-2,4,6-trimethylbenzoylphenylphosphenate are particularly preferred.

[0027] Examples of O-acyloxime compound-based photopolymerization initiators include N-benzoyloxy-1-(4-phenylsulfanylphenyl)butan-1-one-2-imine, N-benzoyloxy-1-(4-phenylsulfanylphenyl)octan-1-one-2-imine, N-benzoyloxy-1-(4-phenylsulfanylphenyl)-3-cyclopentylpropane-1-one-2-imine, N-acetoxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethane-1-imine, and N-acetoxy-1-[9-ethyl-6-{2-methyl-4-(3,3-dimethyl-2,4-dioxacyclopentanylmethyloxy)benzoyl}-9H-carbazole Examples include -3-yl]ethane-1-imine, N-acetoxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-3-cyclopentylpropane-1-imine, N-benzoyloxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-3-cyclopentylpropane-1-one-2-imine, N-acetyloxy-1-[4-(2-hydroxyethyloxy)phenylsulfanylphenyl]propane-1-one-2-imine, and N-acetyloxy-1-[4-(1-methyl-2-methoxyethoxy)-2-methylphenyl]-1-(9-ethyl-6-nitro-9H-carbazole-3-yl)methane-1-imine.

[0028] Examples of benzoin compound polymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0029] Examples of anthracene compound polymerization initiators include 9,10-dimethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 2-ethyl-9,10-diethoxyanthracene. Examples of quinone compound polymerization initiators include 9,10-phenanthrenequinone, 2-ethylanthraquinone, and camphorquinone.

[0030] The content of the polymerization initiator in the monomer composition (excluding the solvent if a solvent is included) is preferably 0.01% to 1% by mass, preferably 0.05% to 0.5% by mass, and more preferably 0.1% to 0.3% by mass. When combining multiple polymerization initiators, the total content should be in the above mass ratio. For example, in a combination of an acetophenone-based photopolymerization initiator and a benzophenone-based photopolymerization initiator, or a combination of an acetophenone-based photopolymerization initiator and an acylphosphine-based photopolymerization initiator, the mass ratio of the acetophenone-based photopolymerization initiator to the benzophenone-based photopolymerization initiator or thioxanthone-based photopolymerization initiator is preferably 3:1 to 1:2, and more preferably 2:1 to 1:1.

[0031] Monomer compositions do not necessarily have to contain chain transfer agents, but they may contain them if it is necessary to prevent the molecular weight of the polymer obtained in the polymerization reaction, as well as the polymer content and viscosity of the polymerizable polymer composition, from becoming too high. There are no particular restrictions on chain transfer agents, but examples include styrene dimers such as α-methylstyrene dimer; mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, and thiophenol; thioglycolic acid (also called mercaptoacetic acid) or its esters such as thioglycolic acid, ethyl thioglycolate, butyl thioglycolate, and bis(mercaptoacetic acid)ethylene glycol; β-mercaptopropionic acid and its esters such as β-mercaptopropionic acid, methyl β-mercaptopropionate, and octyl β-mercaptopropionate, and terpene compounds. These may be used individually or in combination of two or more types. In particular, one or a combination thereof of mercaptan compounds such as n-octyl mercaptan, n-dodecyl mercaptan, and thiophenol, and styrene dimers such as α-methylstyrene dimer is preferred, and one of these is more preferred.

[0032] The content of the chain transfer agent depends on the molecular weight of the resulting polymer, as well as how to control the polymer content and viscosity of the photopolymerizable polymer composition. Preferably, it is 0.001% to 0.1% by mass in the monomer composition, more preferably 0.005% to 0.06% by mass, and particularly preferably 0.01% to 0.5% by mass.

[0033] In the manufacturing method of this embodiment, the monomer composition is usually solvent-free and has little impact on the environment, but a solvent may be included depending on the solubility of each component. Examples of solvents that the monomer composition may contain include methanol, ethanol, isopropanol, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, ethyl acetate, ethyl lactate, methyl lactate, dimethyl sulfoxide, water, etc. These may be used alone or in combination of two or more. The solvent is usually contained in an amount of less than 10% by mass, preferably less than 5% by mass.

[0034] In the manufacturing method of this embodiment, a monomer composition containing the above-mentioned components is prepared, and then the monomer composition is irradiated with light of a specific wavelength to carry out a polymerization reaction. In this case, heating is not required in the manufacturing method of this embodiment using the above-mentioned initiator. However, from the viewpoint of efficiently carrying out photopolymerization, it is preferable to start the monomer composition at a temperature of 20°C to 25°C. In the manufacturing method of the present embodiment, the overall polymerization including the inside of the monomer composition can be efficiently advanced to form a cured product with high hardness, and at the same time, the power consumption per unit weight of the composition required for the production of the polymerizable polymer composition can be reduced, and further, from the viewpoint of enhancing the storage stability of the obtained photopolymerizable polymer composition, light having a peak wavelength of 385 nm ± 10 nm emitted from an LED light source is irradiated onto the monomer composition. Further, in terms of having less interference and absorption with each other, promoting polymerization more efficiently by combination, further reducing the power consumption per unit weight of the composition required for the production of the polymerizable polymer composition, and / or further enhancing the storage stability of the photopolymerizable polymer composition, preferably, light having a peak wavelength of 385 nm ± 10 nm and light having at least one different peak wavelength in the range of 355 to 450 nm are irradiated onto the monomer composition, more preferably, two kinds of light, namely, light having a peak wavelength of 385 nm ± 10 nm and visible light having a peak wavelength of 405 ± 10 nm or visible light having a peak wavelength of 435 nm ± 10 nm are irradiated onto the monomer composition, and particularly preferably, two kinds of light, namely, visible light having a peak wavelength of 385 nm ± 10 nm and visible light having a peak wavelength of 435 nm ± 10 nm are irradiated onto the monomer composition. For example, when light having a peak wavelength of 505 nm ± 10 nm and light having a peak wavelength of 385 nm ± 10 nm are combined, the light having a peak wavelength of 385 nm ± 10 nm is liable to be interfered with and absorbed by the light having a peak wavelength of 505 nm ± 10 nm, and thus the polymerization reaction is inhibited, so it is preferably not combined.

[0035] Photopolymerization is carried out while controlling the irradiation output according to the progress of the polymerization reaction. The illuminance of the LED light source is usually in the range of 5 mW / cm 2 ~600 mW / cm 2 and is preferably set in the range of 8 mW / cm 2 ~300 mW / cm 2 more preferably set in the range of 10 mW / cm 2 ~150 mW / cm 2 even more preferably set in the range of 12 mW / cm 2 ~70 mW / cm 2 and is set in the range of.

[0036] Furthermore, photopolymerization is carried out while controlling the irradiation time and timing according to the progress of the polymerization reaction, and irradiation may be carried out continuously or intermittently. Although it may vary depending on the type of raw material and the amount of photoinitiator, the irradiation time and timing can be carried out intermittently by repeating irradiation times of, for example, 5 to 20 seconds, in order to avoid runaway reactions. However, from the viewpoint of obtaining a composition with a relatively high polymer content while reducing power consumption and improving the storage stability of the photopolymerizable polymer composition, the cumulative light intensity is preferably 15,000 mJ / cm². 2 ~300,000 mJ / cm 2 It is set to be within the range of, more preferably, 18000 mJ / cm². 2 ~280,000 mJ / cm² 2 It is set to be within the range of 20,000 mJ / cm², and more preferably 20,000 mJ / cm². 2 ~250,000 mJ / cm² 2 It is set to fall within the specified range.

[0037] In the manufacturing method of this embodiment, the amount of electricity consumed to produce the photopolymerizable polymer composition is reduced, and the amount of electricity consumed by one light source per 1 kg of monomer composition is less than 105 kWh / kg, and in a preferred embodiment, it is less than 80 kWh / kg.

[0038] 2. Photopolymerizable polymer composition and its cured product Another embodiment of the present invention relates to a photopolymerizable polymer composition obtained by the above-described method. The photopolymerizable polymer composition is a liquid composition in which at least a portion of the monomers in the monomer composition polymerize to form a polymer containing a prepolymer, and which still possesses photopolymerizability. The photopolymerizable polymer composition of this embodiment, obtained by the above-described method, is a liquid composition that contains a polymer with a relatively high average molecular weight, has a relatively high polymer content, and can form a cured product with high hardness.

[0039] Specifically, in the photopolymerizable polymer composition of this embodiment, by controlling the illuminance and irradiation amount of the LED light source in the above-described manufacturing method, the polymer content of dimers or more in the composition is 20% to 85% by mass, preferably 30% to 80% by mass, and particularly preferably 35% to 60% by mass. A high polymer content offers advantages in that it increases the hardness of the cured product using the photopolymerizable polymer composition and improves its production efficiency.

[0040] Furthermore, the weight-average molecular weight of the polymer contained in the photopolymerizable polymer composition of this embodiment is typically 100,000 to 550,000, preferably 120,000 to 480,000, more preferably 180,000 to 450,000, and even more preferably 250,000 to 430,000. A photopolymerizable composition containing polymers with a weight-average molecular weight within this range provides sufficient strength and durability to the cured product obtained by further polymerization. Furthermore, the viscosity of the photopolymerizable polymer composition of this embodiment, as measured at 25°C, is typically 5,000 mPa·s to 55,000 mPa·s, preferably 8,000 mPa·s to 50,000 mPa·s, more preferably 12,000 mPa·s to 48,000 mPa·s, and even more preferably 14,000 mPa·s to 48,000 mPa·s. Such a viscosity range is considered to provide a photopolymerizable composition with suitable coating properties.

[0041] Furthermore, the photopolymerizable polymer composition of this embodiment exhibits excellent storage stability, with a viscosity change rate of less than 5% before and after 12 months of storage in a dark room at 40°C, and less than 3% in a preferred embodiment.

[0042] The photopolymerizable polymer composition of this embodiment can be applied to a substrate, for example, and then irradiated with active energy rays to form a cured product on the entire surface, one side, or part of the substrate.

[0043] The photopolymerizable polymer composition of this embodiment can be applied to a substrate by means of, for example, a bar coater, applicator, die coater, spin coater, spray coater, curtain coater, roll coater, screen printing, dipping, etc.

[0044] The amount of photopolymerizable polymer composition applied to the substrate is not particularly limited and can be adjusted according to the thickness of the cured layer to be formed. As a guideline, an amount that results in a cured layer thickness of 1 μm to 1,000 μm after irradiation with active energy rays is preferred, and an amount that results in a thickness of 10 μm to 800 μm is more preferred.

[0045] There are no particular restrictions on the active energy rays used for curing; in addition to the visible light mentioned above, ultraviolet light may also be used.

[0046] There are no particular restrictions on the substrate material; for example, organic substrates made of paper, wood, or resins such as polycarbonate, polymethyl methacrylate, polystyrene, polyester, polyolefin, polycycloolefin, polyimide, epoxy resin, melamine resin, cellulose resin, ABS resin, AS resin, norbornene-based resin, or inorganic substrates made of metal, glass, metal oxides, etc. can be used.

[0047] The resulting cured product can be used in a variety of applications depending on the composition of the photopolymerizable polymer composition. For example, it can be used as an outdoor display such as digital signage, a coating material for automotive resin substrates, an optical lens such as eyeglass lenses, a sheet material combining fiber materials, a hard coat agent, a resist agent, an adhesive, an electronic component, an electrical component, furniture, housing equipment components, building structures, toys, containers, and the like.

[0048] 3.Polymerization equipment Yet another embodiment of the present invention relates to a polymerization apparatus capable of carrying out the above-described method for producing a photopolymerizable polymer composition. Figure 1 schematically shows an example of the polymerization apparatus of this embodiment, and Figure 2 schematically shows an example of an LED light source constituting the apparatus. As shown in Figure 1, the polymerization apparatus (10) comprises a sealed reaction vessel (4) having a stirrer (1), a temperature sensor (2), and a cooler (3), and an LED light source (5) whose irradiation output and irradiation time can be controlled. The reaction vessel (4) may optionally be equipped with a viscosity sensor (7), and the polymerization state can be observed using the temperature sensor (2) and the viscosity sensor (7). The polymerization apparatus (10) may optionally be equipped with a gas introduction pipe (8) connected to a gas supply source, and before the reaction starts, an inert gas such as argon gas or nitrogen gas is blown into the monomer composition and filled into the reaction vessel to reduce the oxygen concentration inside the vessel and enable the polymerization reaction to be carried out. The LED light source (5) is electrically connected by wires (6) or wirelessly (not shown) to a power supply (not shown) and a control unit (9) that controls the irradiation output, irradiation timing, and irradiation duration. The control unit (9) is also electrically connected to a temperature sensor (2) and a viscosity sensor (7) as needed, and can appropriately change the irradiation output, irradiation timing, and irradiation duration of the LED light source (5) based on information about the temperature and viscosity of the composition in the reaction vessel (4) obtained from these sensors (2, 7). Alternatively, based on information about the temperature and viscosity of the composition in the reaction vessel (4) obtained from these sensors (2, 7), an operator can operate the control unit (9) to appropriately change the irradiation output, irradiation timing, and irradiation duration of the LED light source. The polymerization apparatus (10) may also be equipped with an illuminometer (not shown) to measure the illuminance on the surface of the monomer composition as needed, and the integrated amount of light emitted from the LED light source (5) can be calculated from the obtained illuminance and irradiation duration, and the end time of irradiation can be determined by the integrated amount of light. The operator may use an illuminometer, which is located independently of the polymerization apparatus, to measure the illuminance on the surface of the monomer composition before polymerization begins. The LED light source (5) is installed outside the reaction vessel, for example, by fitting into a through-hole provided in the upper partition wall (11) of the reaction vessel, and emits light of a predetermined wavelength toward the monomer composition inside the reaction vessel (4). Compared to a configuration in which the light source is installed inside the reaction vessel, this configuration allows the polymerization reaction to proceed more efficiently throughout the entire monomer composition, making it easier to obtain a photopolymerizable polymer composition with higher retention stability. As shown in Figure 2, the LED light source (5) has one or more LEDs (12) fixed in a housing (13), and in this example, the LED light source (5) is designed to be detachable from the control unit (9). The LED light source (5) also has a translucent plate (14), such as tempered glass, covering the LEDs (12) in the direction of light emission, and a focusing lens, preferably with a diameter of 3 mm to 12 mm, more preferably with a diameter of 3 mm to 10 mm, may be attached to the front surface in the direction of light emission to adjust the light emission intensity. In the polymerization apparatus (10) of this embodiment, the LED light source (5) is designed to irradiate the reaction vessel with light of a specific peak wavelength, specifically visible light with a wavelength of 385 nm ± 10 nm and, optionally, visible light with at least one different peak wavelength in the range of 355 to 450 nm, directed towards the reaction vessel. The LED light source is preferably designed to irradiate the reaction vessel with two types of light: light having a peak wavelength of 385 nm ± 10 nm and light having different peak wavelengths in the range of 355 to 450 nm. More preferably, it is designed to irradiate the reaction vessel with two types of light: light having a peak wavelength of 385 nm ± 10 nm and visible light with a peak wavelength of 405 nm ± 10 nm, or visible light with a peak wavelength of 435 nm ± 10 nm. Particularly preferably, it is designed to irradiate the reaction vessel with two types of light: visible light with a peak wavelength of 385 nm ± 10 nm and visible light with a peak wavelength of 435 nm ± 10 nm. [Examples]

[0049] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0050] 1. Preparation of photopolymerizable polymer compositions (laboratory level) 1-1.Polymerization equipment As shown in Figure 1, the polymerization apparatus (10) used comprises a 2L light-shielding glass reaction vessel (4) having a stirrer (1), a temperature sensor (2), a viscosity sensor (7), and a cooler (3), a gas introduction pipe (8) connected to a nitrogen gas supply source, and an LED light source (5). The LED light source (5) is detachably connected to an external power supply (not shown) by an electric wire (6), and is further electrically connected to a control unit (9) that controls the irradiation output, irradiation timing, and irradiation duration. The control unit (9) is provided with a switch to turn the power of the LED light source ON / OFF, and the irradiation timing and irradiation duration of the LED light source can be changed as appropriate. The LED light source (5) is installed by fitting it into a through hole provided in the upper partition wall (11) of the reaction vessel, and irradiates the monomer composition inside the reaction vessel (4) with light of a predetermined wavelength. Compared to when it is installed inside the reaction vessel, the polymerization reaction proceeds more efficiently throughout the entire monomer composition, making it easier to obtain a photopolymerizable polymer composition with higher retention stability. As shown in Figure 2, the LED light source (5) has eight LEDs (12) installed in a housing (13), and depending on the test conditions, the LEDs emit light with peak wavelengths of 285 nm ± 10 nm, 365 nm ± 10 nm, 385 nm ± 10 nm, 405 nm ± 10 nm, 435 nm ± 10 nm, or 505 nm ± 10 nm. Depending on the test conditions, the LED light source (5) may also consist of one LED or multiple LEDs emitting light with the same or different peak wavelengths. The LED light source (5) is covered with tempered glass (14) in the direction of light emission, and depending on the test conditions, a focusing lens (not shown) with a diameter of 8 mm, 3 mm, or 10 mm is attached to the front of the LED light source. The LED light source is installed outside the reaction vessel at a distance of 15 cm from the liquid surface of the monomer composition in the reaction vessel, and emits light of a predetermined peak wavelength toward the reaction vessel. The illuminance at the surface of the monomer composition was measured using an illuminometer (UV Power PUCK® II, manufactured by Excelitas Noble Light Japan Co., Ltd.), and the control unit was set to measure the illuminance of the LED light source when the illuminance at the surface of the monomer composition was 15 mW / cm². 2 The settings were configured accordingly. Furthermore, the control unit was configured to perform intermittent irradiation by repeatedly switching the device on and off every 10 seconds, as per the irradiation time and timing.

[0051] 1-2. Examination of LED wavelengths A. Preparation of photopolymerizable polymer compositions [Example 1] In a reaction vessel, while stirring at 200 rpm, add 100 g of methyl methacrylate (product name: Acryester M, manufactured by Mitsubishi Chemical Corporation), 200 g of isobornyl acrylate (product name: IBXA, manufactured by Osaka Organic Chemical Industry Co., Ltd.), 50 g of diethylacrylamide (product name: N,N-diethylacrylamide (DEAA), manufactured by KJ Chemicals Co., Ltd.), 100 g of cyclohexyl acrylate (product name: Acrylics CHA, manufactured by Toagosei Co., Ltd.), and 2-hydroxyethyl methacrylate (product name 50g of Light Ester HOM (manufactured by Kyoeisha Chemical Industry Co., Ltd.) was added, and 0.2g of 1-hydroxycyclohexyl-phenyl ketone (product name: Omnirad184, manufactured by IGM) and 0.1g of ethyl (2,4,6-trimethylbenzoyl)-phenylphosphenate (product name: OmniradTPO-L, manufactured by IGM) were added as photopolymerization initiators. 0.01g of n-dodecyl mercaptan (manufactured by NOF Corporation) was added as a chain transfer agent, and the monomer composition was prepared by uniformly dissolving the mixture while stirring. Next, N2 gas was blown into the monomer composition liquid for 15 minutes. One LED light source emitting light with a peak wavelength of 385nm ± 10nm was connected to one control unit, and an 8mm diameter focusing lens was attached to the front. The LED light source was placed outside the reaction vessel, at a distance of 15cm from the surface of the monomer composition liquid, on top of the apparatus, and the irradiation output was set to an illuminance of 15mW / cm² at the surface of the monomer composition liquid. 2 This was done so that the irradiation would occur by repeatedly switching the control unit on and off at 10-second intervals according to the settings of the control unit, with an integrated light intensity of 150,000 mJ / cm². 2 The process was carried out until the desired result was reached. There was no adhesion to the walls of the reaction vessel, and a colorless, transparent, photopolymerizable polymer composition was collected in a light-shielding bottle.

[0052] [Comparative Example 1] Photopolymerization was carried out under the same conditions as in Example 1, except that the LED light source emitting light with a peak wavelength of 285 nm ± 10 nm was changed to one LED. No adhesion was observed on the walls of the reaction vessel, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0053] [Comparative Example 2] Photopolymerization was carried out under the same conditions as in Example 1, except that the LED light source emitting light with a peak wavelength of 365 nm ± 10 nm was changed to one LED. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0054] [Comparative Example 3] Photopolymerization was carried out under the same conditions as in Example 1, except that the LED light source emitting light with a peak wavelength of 505 nm ± 10 nm was changed to one. The integrated light intensity was 150,000 mJ / cm². 2 Polymerization was carried out until the desired consistency was reached, but no thickening was observed, and the reaction did not occur.

[0055] [Comparative Example 4] Photopolymerization was carried out under the same conditions as in Example 1, except that one LED light source emitting light with a peak wavelength of 285 nm ± 10 nm and one LED light source emitting light with a peak wavelength of 365 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0056] [Example 2] Photopolymerization was carried out under the same conditions as in Example 1, except that an LED light source emitting light with a peak wavelength of 365 nm ± 10 nm and one LED light source emitting light with a peak wavelength of 385 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0057] [Example 3] Photopolymerization was carried out under the same conditions as in Example 1, except that one LED light source emitting light with a peak wavelength of 385 nm ± 10 nm and one LED light source emitting light with a peak wavelength of 405 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0058] [Example 4] Photopolymerization was carried out under the same conditions as in Example 1, except that one LED light source emitting light with a peak wavelength of 385 nm ± 10 nm and one LED light source emitting light with a peak wavelength of 435 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0059] [Comparative Example 5] Photopolymerization was carried out under the same conditions as in Example 1, except that one LED light source emitting light with a peak wavelength of 385 nm ± 10 nm and one LED light source emitting light with a peak wavelength of 505 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0060] [Comparative Example 6] Photopolymerization was carried out under the same conditions as in Example 1, except that one LED light source emitting light with a peak wavelength of 285 nm ± 10 nm, one LED light source emitting light with a peak wavelength of 365 nm ± 10 nm, and one LED light source emitting light with a peak wavelength of 405 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0061] [Comparative Example 7] Photopolymerization was carried out under the same conditions as in Example 1, except that one LED light source emitting light with a peak wavelength of 285 nm ± 10 nm, one LED light source emitting light with a peak wavelength of 365 nm ± 10 nm, and one LED light source emitting light with a peak wavelength of 435 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0062] [Example 5] Photopolymerization was carried out under the same conditions as in Example 1, except that an LED light source emitting light with a peak wavelength of 365 nm ± 10 nm, one LED light source emitting light with a peak wavelength of 385 nm ± 10 nm, and one LED light source emitting light with a peak wavelength of 405 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0063] [Example 6] Photopolymerization was carried out under the same conditions as in Example 1, except that an LED light source emitting light with a peak wavelength of 365 nm ± 10 nm, one LED light source emitting light with a peak wavelength of 385 nm ± 10 nm, and one LED light source emitting light with a peak wavelength of 435 nm ± 10 nm were installed. No adhesion to the walls of the reaction vessel was observed, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0064] [Example 7] Photopolymerization was carried out under the same conditions as in Example 1, except that one LED light source emitting light with a peak wavelength of 385 nm ± 10 nm, one LED light source emitting light with a peak wavelength of 405 nm ± 10 nm, and one LED light source emitting light with a peak wavelength of 435 nm ± 10 nm were installed. No adhesion was found on the walls of the reaction vessel, and a colorless, transparent photopolymerizable composition was recovered in a light-shielding bottle.

[0065] The preparation conditions and raw material compositions of the photopolymerizable compositions in Examples 1-7 and Comparative Examples 1-7 are outlined below. [Table 1]

[0066] [Table 2]

[0067] [Table 3]

[0068] B. Characterization of the obtained photopolymerizable polymer composition The photopolymerizable polymer compositions obtained in Examples 1-7 and Comparative Examples 1-7 were evaluated for their properties by performing the following tests.

[0069] Power consumption per light source per 1 kg of monomer composition The power consumption of one LED light source used in each example and comparative example is as follows: • LED light source with peak wavelength of 285nm ± 10nm: 20.0W • LED light source with peak wavelength of 365nm ± 10nm: 19.3W • LED light source with peak wavelength of 385nm ± 10nm: 18.8W • LED light source with peak wavelength of 405nm ± 10nm: 12.5W • LED light source with peak wavelength of 435nm±10nm: 6.3W • LED light source with peak wavelength of 505nm ± 10nm: 5.0W The irradiation time was determined from the cumulative light intensity of each example and comparative example, and the power consumption per light source per 1 kg of monomer composition was calculated using the formula: power consumption (W) × irradiation time (h) / mass of monomer composition (kg). The following criteria were also used for evaluation. A: 30kWh / kg to less than 80kWh / kg B: 80kWh / kg to less than 105kWh / kg C: 105kWh / kg to less than 150kWh / kg

[0070] Content of polymers with dimers or more The photopolymerizable polymer compositions obtained in each example and comparative example were heated in a 150°C dryer for 2 hours. The mass of the residue after heating was measured, and the mass ratio to the mass of the photopolymerizable polymer obtained in each example and comparative example before heating was calculated. This was then defined as the content of dimers or more of polymer contained in the photopolymerizable polymer compositions obtained in each example and comparative example.

[0071] viscosity The viscosity of the compositions obtained in each example and comparative example at 25°C was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: BMII type viscometer).

[0072] Weight-average molecular weight of polymers The weight-average molecular weight of the polymers in the compositions obtained in each example and comparative example was measured by GPC using a SHODEX KF-806M manufactured by Showa Denko Corporation.

[0073] Viscosity change rate The viscosity of the compositions obtained in each example and comparative example was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: BMII viscometer) before and after storage at 40°C in a dark room for 12 months, and the percentage change in viscosity before and after storage was determined. The following evaluation criteria were used for evaluation. A: Less than 0-3% B: 3% to less than 5% C: 5% to less than 10% D: 10% or more

[0074] The properties of the photopolymerizable polymer compositions obtained in Examples 1-7 and Comparative Examples 1-7 are shown below. [Table 4] [Table 5] [Table 6]

[0075] C. Evaluation of the hardness of cured products of photopolymerizable polymer compositions Coating agents were prepared by adding 3 g of 1-hydroxycyclohexyl phenyl ketone (product name: Omnirad 184, manufactured by IGM) to 100 parts of the photopolymerization polymer compositions of Examples 1-5 and Comparative Examples 1, 2, 4, and 5. This coating agent was applied to a PET film (Toyobo Co., Ltd., A4300) using a BYK-Gaidner applicator (product name: 5558 bar applicator), and then exposed to ultraviolet light at 500 mJ / cm² using a Heraeus Inc. Light Hammer 10 under air conditions. 2 (Illuminance 1,500mW / cm 2Ultraviolet irradiation was performed to achieve the required irradiation dose, and a coating layer with a thickness of 5 μm was formed on the PET film. The hardness of each obtained coating layer was evaluated by performing the following pencil scratch test.

[0076] [Pencil hardness of hardened coating] In accordance with JIS K 5600-5-4 (1999), a pencil scratch test was conducted on the coated surface of the substrate on which the above coating layer was formed, under a load of 750g, and evaluated according to the following criteria. A: H or above B: HB ~ FC: Less than HB D: Uncured (tack remains)

[0077] The test results are shown below. [Table 7] The cured products of Examples 1 to 5 showed good curability and surface hardness at all levels, but the cured products of Comparative Examples 1 and 2 and Comparative Examples 4 and 5 exhibited reduced hardness and tackiness, resulting in insufficient curability and strength.

[0078] 1-3. Examination of initiator, chain transfer agent, and lens diameter A. Preparation of photopolymerizable polymer compositions [Example 8] Photopolymerization was carried out under the same conditions as in Example 2, except that the photopolymerization initiator was changed to 0.2 g of benzophenone (manufactured by Matsugaki Pharmaceutical Co., Ltd.). No adhesion to the reaction vessel walls was observed, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0079] [Example 9] Photopolymerization was carried out under the same conditions as in Example 2, except that the photopolymerization initiator was changed to 0.2 g of 1-hydroxycyclohexyl phenyl ketone (product name: Omnirad184, manufactured by IGM). No adhesion to the reaction vessel walls was observed, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0080] [Example 10] Photopolymerization was carried out under the same conditions as in Example 2, except that the photopolymerization initiator was changed to 0.2 g of ethyl(2,4,6-trimethylbenzoyl)-phenylphosphenate (product name: OmniradTPO-L, manufactured by IGM). No adhesion to the reaction vessel walls was observed, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0081] [Comparative Example 8] Photopolymerization was carried out under the same conditions as in Example 2, except that 0.1 g of t-butyl hydroperoxide (product name: Luperox TBH, manufactured by Arkema Yoshitomi Co., Ltd.), a thermal polymerization initiator, was added instead of a photopolymerization initiator, and 0.05 g of n-dodecyl mercaptan (manufactured by NOF Corporation) was added as a chain transfer agent. The integrated light intensity was 150,000 mJ / cm². 2 Polymerization was carried out until the desired consistency was reached, but no thickening was observed, and the reaction did not occur.

[0082] [Comparative Example 9] Photopolymerization was carried out under the same conditions as in Example 2, except that 0.1 g of t-butyl hydroperoxide (product name: Luperox TBH, manufactured by Arkema Yoshitomi Co., Ltd.), a thermal polymerization initiator, was added in addition to the photopolymerization initiator. No adhesion was observed on the walls of the reaction vessel, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0083] [Example 11] Photopolymerization was carried out under the same conditions as in Example 2, except that the photopolymerization initiator and transfer chain agent were omitted. No adhesion to the reaction vessel walls was observed, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0084] [Example 12] Photopolymerization was carried out under the same conditions as in Example 2, except that 0.02 g of α-methylstyrene dimer (product name: Nofmer MSD, manufactured by NOF Corporation) was added as a chain transfer agent. No adhesion to the reaction vessel walls was observed, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0085] [Example 13] Photopolymerization was carried out under the same conditions as in Example 2, except that the chain transfer agent was changed to 0.05 g of α-methylstyrene dimer (product name: Nofmer MSD, manufactured by NOF Corporation). No adhesion to the reaction vessel walls was observed, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0086] [Example 14] Photopolymerization was carried out under the same conditions as in Example 2, except that the focusing lens was changed to a 3 mm diameter focusing lens. No adhesion to the reaction vessel walls was observed, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0087] [Example 15] Photopolymerization was carried out under the same conditions as in Example 2, except that the focusing lens was changed to a 10 mm diameter focusing lens. No adhesion to the reaction vessel walls was observed, and a colorless, transparent, photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0088] The preparation conditions and raw material compositions of the photopolymerizable compositions of Examples 8-15 and Comparative Examples 8 and 9 are outlined below. [Table 8]

[0089] B. Characterization of the obtained photopolymerizable polymer composition The photopolymerizable polymer compositions obtained in Examples 8-15 and Comparative Examples 8 and 9 were evaluated for their properties by performing the following tests.

[0090] Power consumption per light source per 1 kg of monomer composition The power consumption of one LED light source used in each example and comparative example is as follows: • LED light source with peak wavelength of 285nm ± 10nm: 20.0W • LED light source with peak wavelength of 365nm ± 10nm: 19.3W • LED light source with peak wavelength of 385nm ± 10nm: 18.8W • LED light source with peak wavelength of 405nm ± 10nm: 12.5W • LED light source with peak wavelength of 435nm±10nm: 6.3W • LED light source with peak wavelength of 505nm ± 10nm: 5.0W The irradiation time was determined from the cumulative light intensity of each example and comparative example, and the power consumption per light source per 1 kg of monomer composition was calculated using the formula: power consumption (W) × irradiation time (h) / mass of monomer composition (kg). The following criteria were also used for evaluation. A: 30kWh / kg to less than 80kWh / kg B: 80kWh / kg to less than 105kWh / kg C: 105kWh / kg to less than 150kWh / kg

[0091] Content of polymers with dimers or more The photopolymerizable polymer compositions obtained in each example and comparative example were heated in a 150°C dryer for 2 hours. The mass of the residue after heating was measured, and the mass ratio to the mass of the photopolymerizable polymer obtained in each example and comparative example before heating was calculated. This was then defined as the content of dimers or more of polymer contained in the photopolymerizable polymer compositions obtained in each example and comparative example.

[0092] viscosity The viscosity of the compositions obtained in each example and comparative example at 25°C was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: BMII type viscometer).

[0093] Weight-average molecular weight of polymers The weight-average molecular weight of polymers with dimers or more was measured by GPC using a SHODEX KF-806M manufactured by Showa Denko Corporation. The result was approximately 60,000.

[0094] Viscosity change rate The viscosity of the compositions obtained in each example and comparative example was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: BMII viscometer) before and after storage at 40°C in a dark room for 12 months, and the percentage change in viscosity before and after storage was determined. The following evaluation criteria were used for evaluation. A: Less than 0-3% B: 3% to less than 5% C: 5% to less than 10% D: 10% or more

[0095] The properties of the photopolymerizable polymer compositions obtained in Examples 8-15 and Comparative Examples 8-9 are shown below. [Table 9]

[0096] 2. Investigation using a pilot device 2-1. Polymerization equipment Polymerization conditions were investigated using a scaled-up pilot apparatus. The pilot apparatus used had the same basic configuration as the polymerization apparatus shown in Figure 1, but differed in the following points. Reaction vessel: A 200L stainless steel reaction vessel. Control Unit and Light Source: Equipped with three control units, each connected to four LED light sources. The LED light sources are installed at a distance of 30 cm from the liquid surface of the monomer composition.

[0097] 2-2. Preparation of photopolymerizable polymer compositions [Example 16] In a reaction vessel, while stirring at 100 rpm, add 30 kg of methyl methacrylate (product name: Acryester M, manufactured by Mitsubishi Chemical Corporation), 60 kg of isobornyl acrylate (product name: IBXA, manufactured by Osaka Organic Chemical Industry Co., Ltd.), 15 kg of diethylacrylamide (product name: N,N-diethylacrylamide (DEAA), manufactured by KJ Chemicals Co., Ltd.), 40 kg of cyclohexyl acrylate (product name: Acrylics CHA, manufactured by Toagosei Co., Ltd.), and 2-hydroxyethyl methacrylate (product name: Ly 15 kg of toester HOM (manufactured by Kyoeisha Chemical Industry Co., Ltd.) was added, and 0.06 kg of 1-hydroxycyclohexyl-phenyl ketone (product name: Omnirad184, manufactured by IGM) and 0.03 kg of ethyl (2,4,6-trimethylbenzoyl)-phenylphosphenate (product name: OmniradTPO-L, manufactured by IGM) were added as photopolymerization initiators, and 0.003 kg of n-dodecyl mercaptan (manufactured by NOF Corporation) was added as a chain transfer agent. The monomer composition was prepared by dissolving the mixture uniformly while stirring. Next, N2 gas was blown into the monomer composition for 15 minutes. Subsequently, twelve LED light sources, each emitting light with a peak wavelength of 385 nm ± 10 nm, were connected to three control units. A focusing lens with a diameter of 8 mm was attached to the front of each unit. The LED light sources were installed outside the reaction vessel, at a distance of 30 cm from the surface of the monomer composition, on top of the apparatus. The irradiation output was set to an illuminance of 15 mW / cm² at the surface of the monomer composition. 2 This was done so that the irradiation would occur by repeatedly switching the control unit on and off at 10-second intervals according to the settings of the control unit, with an integrated light intensity of 200,000 mJ / cm². 2 Polymerization was carried out until the desired result was reached. There was no adhesion to the reaction vessel walls, and a colorless, transparent, photopolymerizable polymer composition was collected in a light-shielding bottle.

[0098] [Comparative Example 10] Except for changing to 12 LED light sources emitting light with a peak wavelength of 285 nm ± 10 nm, photopolymerization was carried out under the same conditions as in Example 16, and no adhesion to the reaction vessel walls was observed, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0099] [Comparative Example 11] Except for changing to 12 LED light sources emitting light with a peak wavelength of 365 nm ± 10 nm, photopolymerization was carried out under the same conditions as in Example 16, and no adhesion to the reaction vessel walls was observed, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0100] [Comparative Example 12] The photopolymerization procedure was carried out under the same conditions as in Example 16, except that six LED light sources emitting light with a peak wavelength of 285 nm ± 10 nm were used, and six LED light sources emitting light with a peak wavelength of 365 nm ± 10 nm were used. No adhesion was observed on the walls of the reaction vessel, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0101] [Example 17] Except for changing the LED light source to six LED light sources emitting light with a peak wavelength of 365 nm ± 10 nm and six LED light sources emitting light with a peak wavelength of 385 nm ± 10 nm, photopolymerization was carried out in the same manner as in Example 16, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle without any adhesion to the walls of the reaction vessel.

[0102] [Example 18] Except for changing the LED light source to six LED light sources emitting light with a peak wavelength of 385 nm ± 10 nm and six LED light sources emitting light with a peak wavelength of 405 nm ± 10 nm, photopolymerization was carried out in the same manner as in Example 16, and no adhesion to the walls of the reaction vessel was observed, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0103] [Example 19] Except for changing the LED light source to six LED light sources emitting light with a peak wavelength of 385 nm ± 10 nm and six LED light sources emitting light with a peak wavelength of 435 nm ± 10 nm, photopolymerization was carried out in the same manner as in Example 16, and no adhesion to the walls of the reaction vessel was observed, and a colorless, transparent photopolymerizable polymer composition was recovered in a light-shielding bottle.

[0104] The preparation conditions and raw material compositions of the photopolymerizable compositions in Examples 16-19 and Comparative Examples 10-12 are outlined below. [Table 10]

[0105] [Table 11]

[0106] B. Characterization of the obtained photopolymerizable polymer composition The photopolymerizable polymer compositions obtained in Examples 16-19 and Comparative Examples 10-12 were evaluated for their properties by performing the following tests.

[0107] Power consumption per light source per 1 kg of monomer composition The power consumption of one LED light source used in each example and comparative example is as follows: • LED light source with peak wavelength of 285nm ± 10nm: 20.0W • LED light source with peak wavelength of 365nm ± 10nm: 19.3W • LED light source with peak wavelength of 385nm ± 10nm: 18.8W • LED light source with peak wavelength of 405nm ± 10nm: 12.5W • LED light source with peak wavelength of 435nm±10nm: 6.3W • LED light source with peak wavelength of 505nm ± 10nm: 5.0W The irradiation time was determined from the cumulative light intensity of each example and comparative example, and the power consumption per light source per 1 kg of monomer composition was calculated using the formula: power consumption (W) × irradiation time (h) / mass of monomer composition (kg). The following criteria were also used for evaluation. A: 40kWh / kg to less than 105kWh / kg B: 105kWh / kg to less than 140kWh / kg C: 140kWh / kg to less than 200kWh / kg

[0108] Content of polymers with dimers or more The photopolymerizable polymer compositions obtained in each example and comparative example were heated in a 150°C dryer for 2 hours. The mass of the residue after heating was measured, and the mass ratio to the mass of the photopolymerizable polymer obtained in each example and comparative example before heating was calculated. This was then defined as the content of dimers or more of polymer contained in the photopolymerizable polymer compositions obtained in each example and comparative example.

[0109] viscosity The viscosity of the compositions obtained in each example and comparative example at 25°C was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: BMII type viscometer).

[0110] Weight-average molecular weight of polymers The weight-average molecular weight of polymers with dimers or more was measured by GPC using a SHODEX KF-806M manufactured by Showa Denko Corporation.

[0111] Viscosity change rate The viscosity of the compositions obtained in each example and comparative example was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: BMII viscometer) before and after storage at 40°C in a dark room for 12 months, and the percentage change in viscosity before and after storage was determined. The following evaluation criteria were used for evaluation. A: Less than 0-3% B: 3% to less than 5% C: 5% to less than 10% D: 10% or more

[0112] The properties of the photopolymerizable polymer compositions obtained in Examples 16-19 and Comparative Examples 10-12 are summarized below. [Table 12] [Table 13] [Explanation of Symbols]

[0113] 1: Agitator 2: Temperature detector 3:Cooler 4: Reaction vessel 5:LED light source 6:Electric wire 7: Viscosity detector 8: Gas inlet pipe 9: Control Unit 10: Polymerization equipment 11: Upper partition of the reaction vessel 12: LED 13: Cabinet 14: Translucent plate

Claims

1. A step of preparing a monomer composition by mixing at least one monofunctional or bifunctional or more (meth)acrylic acid monomer selected from a group consisting of an alkyl alcohol having 1 to 12 carbon atoms, a cycloalkyl alcohol having 6 to 8 carbon atoms, an acrylamide monomer, isobornyl (meth)acrylate, and a hydroxyalkyl (meth)acrylic acid ester having 1 to 5 carbon atoms, a polymerization initiator, a chain transfer agent if necessary, and a solvent if necessary, wherein the polymerization initiator is one or more photopolymerization initiators selected from the group consisting of acetophenone polymerization initiators, benzophenone polymerization initiators, thioxanthone polymerization initiators, and acylphosphine polymerization initiators. If necessary, the process involves filling the reaction atmosphere with an inert gas, A step of obtaining a photopolymerizable composition containing a prepolymer by irradiating the monomer composition with visible light having a peak wavelength of 385 nm ± 10 nm alone, or in combination with visible light having a peak wavelength of 385 nm ± 10 nm and visible light having at least one different peak wavelength in the range of 355 to 450 nm, while stirring the monomer composition. A method for producing a photopolymerizable composition containing [the specified substance].

2. The manufacturing method according to Claim 1, wherein the monomer composition is irradiated with visible light having a peak wavelength of 385 nm ± 10 nm, visible light having a peak wavelength of 405 nm ± 10 nm, or visible light having a peak wavelength of 435 nm ± 10 nm.

3. The manufacturing method according to claim 1, wherein the monomer composition is irradiated with visible light having a peak wavelength of 385 nm ± 10 nm and visible light having a peak wavelength of 435 nm ± 10 nm.

4. The cumulative light intensity is 15,000 mJ / cm². ２ ~300000mJ / cm ２ The manufacturing method according to claim 1.

5. The manufacturing method according to claim 1, wherein the polymerization initiator is one or more photopolymerization initiators selected from the group consisting of acetophenone-based polymerization initiators, benzophenone-based polymerization initiators, and acylphosphine-based polymerization initiators.

6. The manufacturing method according to claim 1, wherein the chain transfer agent is at least one of α-methylstyrene dimer, a mercaptan compound, and a terpene compound.

7. The manufacturing method according to claim 1, wherein the polymer content in the photopolymerizable composition is 20% by mass to 85% by mass.

8. The manufacturing method according to claim 1, wherein the weight-average molecular weight of the polymer in the photopolymerizable composition is 120,000 to 480,000, and the viscosity of the photopolymerizable composition measured at 25°C is 8,000 mPa·s to 50,000 mPa·s.

9. A photopolymerizable composition produced by the method of any one of claims 1 to 8, wherein the monomer is at least one of (meth)acrylic acid esters esterified with an alkyl alcohol having 1 to 12 carbon atoms, (meth)acrylic acid esters esterified with a cycloalkyl alcohol having 6 to 8 carbon atoms, acrylamide monomer, isobornyl (meth)acrylate, hydroxyalkyl (meth)acrylic acid esters having 1 to 5 carbon atoms, and bifunctional or more (meth)acrylic acid esters, the content of dimers or more polymers contained in the photopolymerizable composition is 20% to 85% by mass, the weight-average molecular weight of the polymer is 120,000 to 480,000, and the viscosity measured at 25°C is 8,000 mPa·s to 50,000 mPa·s.

10. The photopolymerizable composition according to claim 9, wherein the viscosity change rate before and after holding at 40°C in a dark room for 12 months is less than 5%.

11. A cured product obtained by curing the photopolymerizable composition according to claim 10 by light irradiation.

12. An article having the cured product described in claim 11 on a substrate made of paper, wood, resin, metal, glass, or metal oxide.

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