Fluorine-containing active energy ray-curable composition

Abstract

Provided is a fluorine-containing active energy ray-curable composition that has a low refractive index and contains a fluoropolyether group-containing acrylic compound that is compatible with a photopolymerization initiator to form a transparent composition. The present invention provides a fluoropolyether group-containing acrylic compound of the following formula: V 2 -Rf 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a (Rf 2 is a divalent perfluoropolyether group having a number average molecular weight of 2,000 to 40,000, which is composed of a perfluoroalkylene group having 1 to 6 carbon atoms and an oxygen atom, and both ends of which are perfluoroalkylene groups having 2 to 6 carbon atoms. 2 is a (b'+1)valent hydrocarbon group. X 2 is an acrylic group-containing monovalent organic group. R 1 is H or a monovalent hydrocarbon group having 1 to 8 carbon atoms. 2 is H, F, or -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a a is 0 or 1, and b' is an integer from 1 to 10. and a photopolymerization initiator.

Description

[Technical Field]

[0001] The present invention relates to a fluorine-containing active energy ray-curable composition containing a fluoropolyether group-containing acrylic compound which has a low refractive index and is compatible with a photopolymerization initiator to form a transparent composition. [Background technology]

[0002] Conventionally, polymerizable monomers having a perfluoroalkyl group in the side chain, such as polymers containing a fluorine-containing alkyl ester of acrylic acid or a fluorine-containing alkyl ester of methacrylic acid, have been widely known as fluorine compounds that can be cured by irradiation with light such as ultraviolet light. These fluorine-containing acrylic compounds have been widely used in optical materials, taking advantage of their excellent curing properties upon irradiation with ultraviolet light, high transparency, and low refractive index. For example, Japanese Patent Laid-Open Publication No. 6-136062 (Patent Document 1) discloses the application of fluorine-containing acrylic compounds in the side chain to antireflection coatings, and Japanese Patent Laid-Open Publication No. 5-32749 (Patent Document 2) discloses their use as coating materials for optical fibers.

[0003] On the other hand, when the fluorine content of these fluorine-containing acrylic compounds is increased for the purpose of further lowering the refractive index, etc., the solubility in non-fluorinated organic compounds decreases, and the compounds become insoluble in general photopolymerization initiators, making it impossible to obtain a transparent cured product, or the crystallinity increases, resulting in a loss of transparency, and it has been difficult to obtain a transparent cured product having a refractive index of a certain value or less.

[0004] Under such circumstances, the present inventors have been developing fluorine-containing acrylic compounds, and have proposed, for example, a fluorine-containing curable composition that can be cured with ultraviolet light and can form a transparent cured product having a low refractive index, as shown in JP-A No. 2006-233172 (Patent Document 3).

[0005] Although these compositions can form transparent cured products with low refractive indexes, there is a problem in that a photopolymerization initiator modified with a perfluoropolyether group must be separately synthesized for these compositions. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-136062 [Patent Document 2] Japanese Patent Application Publication No. 5-32749 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-233172 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fluorine-containing active energy ray-curable composition containing a fluoropolyether group-containing acrylic compound which has a low refractive index and is compatible with a photopolymerization initiator to form a transparent composition. [Means for solving the problem]

[0008] As a result of further investigations to achieve the above object, the present inventors have found that a fluoropolyether group-containing acrylic compound represented by the following general formula (1) has a low refractive index and is compatible with general photopolymerization initiators to form a transparent composition, thereby completing the present invention. V 2 -Rf 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a (1) (In the formula, Rf 2Y is a divalent perfluoropolyether group having a number average molecular weight of 500 to 40,000 and composed of a perfluoroalkylene group having 1 to 6 carbon atoms and an oxygen atom. 2 are independently (b'+1)-valent organic groups having 1 to 20 carbon atoms. 2 R is independently a monovalent organic group containing an acrylic group or an α-substituted acrylic group, and contains an average of at least one such acrylic group or α-substituted acrylic group per molecule. 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms. 2 is a hydrogen atom, a fluorine atom, or -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a a is 0 or 1, and b' is an integer of 1 to 10.

[0009] Accordingly, the present invention provides the following fluorine-containing active energy ray-curable composition. [1] The following general formula (1) V 2 -Rf 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a (1) (In the formula, Rf 2 is a divalent perfluoropolyether group having a number average molecular weight of 2,000 to 40,000, which is composed of a perfluoroalkylene group having 1 to 6 carbon atoms and an oxygen atom, and both ends of which are perfluoroalkylene groups having 2 to 6 carbon atoms. 2 are independently hydrocarbon groups having 1 to 20 carbon atoms and a valence of (b'+1). 2 R is independently a monovalent organic group containing an acrylic group or an α-substituted acrylic group, and contains an average of at least one such acrylic group or α-substituted acrylic group per molecule. 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms. 2 is a hydrogen atom, a fluorine atom, or -C(=O)-NR1 a [Y 2 (X 2 ) b’ ] 2-a a is 0 or 1, and b' is an integer of 1 to 10. and a photopolymerization initiator. [2] In general formula (1), Rf 2 is expressed as follows: [ka] (In the formula, c is independently an integer of 2 to 6 for each unit. d, e, f, g, h, and i are each an integer of 0 to 200, and d+e+f+g+h+i=4 to 200. Each of these units may be linear or branched, and each repeating unit shown in parentheses with d, e, f, g, h, and i may be bonded randomly.) The fluorine-containing active energy ray-curable composition according to [1], wherein the divalent perfluoropolyether group is represented by the following formula: [3] In general formula (1), Rf 2 is the following structural formula -CF2CF2O-(CF2CF2CF2O) q -CF2CF2- (In the formula, q is an integer of 4 to 200.) [ka] (wherein r is an integer of 1 to 6, and C r F 2r O may be linear or branched, s is an integer of 0 to 6, t and u are each an integer of 1 to 200, t+u is an integer of 2 to 200, and s+t+u is an integer of 4 to 200. v is an integer of 5 to 200. The fluorine-containing active energy ray-curable composition according to [1] or [2], wherein the divalent perfluoropolyether group is selected from divalent perfluoropolyether groups represented by the following formula: [4] In general formula (1), R 1 The fluorine-containing active energy ray-curable composition according to any one of [1] to [3], wherein is a hydrogen atom and a is 1. [5] In general formula (1), Y 2 The fluorine-containing active energy ray-curable composition according to any one of [1] to [4], wherein: [ka] (In the formula, * represents a bond bonded to N, and ** represents X 2 ) [6] In general formula (1), X 2 is the following structural formula [ka] (In the formula, R 2 are independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; W is a single bond, or a divalent or trivalent hydrocarbon group which may contain one or more bonds selected from an ether bond, an ester bond, and a urethane bond; and n is 1 or 2. The fluorine-containing active energy ray-curable composition according to any one of [1] to [5], which is represented by the following formula: [7] The fluorine-containing active energy ray-curable composition according to any one of [1] to [6], which does not contain a solvent. [8] The fluorine-containing active energy ray-curable composition according to any one of [1] to [7], wherein 100 parts by mass of the fluoropolyether group-containing acrylic compound and 1 part by mass of 2-hydroxy-2-methylpropiophenone or 2-diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide are mixed to form a blended composition having a uniform appearance. [Effects of the Invention]

[0010] The fluoropolyether group-containing acrylic compound of the present invention has a low refractive index and is compatible with a photopolymerization initiator to form a transparent composition, making it useful as a material for fluorine-containing active energy ray-curable compositions for optical components, etc. DETAILED DESCRIPTION OF THE INVENTION

[0011] The fluoropolyether group-containing acrylic compound of the present invention is characterized by being represented by the following general formula (1). V 2 -Rf 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a (1) (In the formula, Rf 2 Y is a divalent perfluoropolyether group having a number average molecular weight of 500 to 40,000 and composed of a perfluoroalkylene group having 1 to 6 carbon atoms and an oxygen atom. 2 are independently (b'+1)-valent organic groups having 1 to 20 carbon atoms. 2 R is independently a monovalent organic group containing an acrylic group or an α-substituted acrylic group, and contains an average of at least one such acrylic group or α-substituted acrylic group per molecule. 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms. 2 is a hydrogen atom, a fluorine atom, or -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a a is 0 or 1, and b' is an integer of 1 to 10.

[0012] In the present invention, "acrylic compound" is a general term for compounds having an acrylic group or an α-substituted acrylic group, and includes compounds in which two or more acrylic groups or α-substituted acrylic groups have been introduced into the side chains or ends of various polymers by any method. Furthermore, in the present invention, "(meth)acrylate" refers to either or both of acrylate and methacrylate, "(meth)acrylic group" refers to either or both of an acrylic group and a methacrylic group, and "(meth)acrylic acid" refers to either or both of acrylic acid and methacrylic acid.

[0013] The fluoropolyether group-containing acrylic compound of the present invention has a perfluoropolyether group as a group having a low refractive index, an amide bond as a group for improving compatibility with a photopolymerization initiator, and an acrylic group or an α-substituted acrylic group, and therefore has a low refractive index and is compatible with a photopolymerization initiator to form a transparent composition.Furthermore, it can be used as a material for a fluorine-containing active energy curable composition that can be cured by active energy rays such as ultraviolet rays and electron beams.

[0014] The fluoropolyether group-containing acrylic compound of the present invention must have an amide structure in its structure. The amide structure acts as a hydrogen bond acceptor, which interacts with hydrogen atoms in the photopolymerization initiator to improve compatibility with the photopolymerization initiator. As a result, the compound is compatible with the photopolymerization initiator and can form a transparent composition.

[0015] In the above formula (1), Rf 2 is a divalent perfluoropolyether group having a number average molecular weight of 500 to 40,000 and consisting of a perfluoroalkylene group having 1 to 6 carbon atoms and an oxygen atom, and Rf 2 The alkylene group preferably has a perfluorooxyalkylene structure having 1 to 6 carbon atoms, particularly the following perfluorooxyalkylene structure having 1 to 3 carbon atoms, as the main repeating unit. -CF2O- -CF2CF2O- -CF(CF3)CF2O- -CF2CF2CF2O- These structures may be any one homopolymer, or a random or block polymer consisting of a plurality of structures.

[0016] Rf having such a structure 2 Examples of the above include the following structures: [ka] (In the formula, c is independently an integer of 2 to 6 for each unit. d, e, f, g, h, and i are each an integer of 0 to 200, and d+e+f+g+h+i=4 to 200. Each of these units may be linear or branched, and each repeating unit shown in parentheses with d, e, f, g, h, and i may be bonded randomly.)

[0017] In the above formula, c is independently for each unit an integer of 2 to 6, preferably 2 to 4. When c is 1, the amide bond in the compound is susceptible to hydrolysis due to the electron-withdrawing properties of the fluorine atom and oxygen atom, and decomposition progresses during storage; therefore, c is preferably independently for each unit an integer of 2 to 6. Furthermore, d, e, f, g, h, and i are each an integer of 0 to 200, preferably d is an integer of 0 to 100, e is an integer of 5 to 100, f is an integer of 5 to 100, g is an integer of 0 to 100, h is an integer of 0 to 100, and i is an integer of 0 to 100, and d+e+f+g+h+i=4 to 200, preferably 10 to 150, and more preferably 30 to 150. In the above formula, each unit may be linear or branched, and each repeating unit shown in parentheses with d, e, f, g, h, and i may be randomly bonded.

[0018] Rf 2The number-average molecular weight of the corresponding structural portion is required to be within the range of 500 to 40,000, preferably 2,000 to 25,000, and the molecular weight distribution (or polymerization degree distribution) is not particularly limited. If the number-average molecular weight is less than 500, the refractive index will increase due to a decrease in the fluorine atom content, and if it exceeds 40,000, the handleability will decrease due to an increase in viscosity, and the compatibility with the polymerization initiator will decrease to a non-negligible extent due to an increase in the fluorine atom content. In the present invention, the molecular weight (or polymerization degree or number of repeating units) may be determined as the polystyrene-equivalent number-average molecular weight (or number-average polymerization degree) by gel permeation chromatography (GPC) analysis using a fluorine-based solvent as the developing solvent, 1 H-NMR analysis and 19 It may also be a number average molecular weight (or number average degree of polymerization) calculated from the characteristic peak intensity ratio between the terminal structure and main chain structure of the fluoropolyether group-containing acrylic compound based on F-NMR analysis (the same applies hereinafter).

[0019] Rf having such a structure 2 Suitable examples of the above include the following structures: -CF2CF2O-(CF2CF2CF2O) q -CF2CF2- (In the formula, q is an integer of 4 to 200, preferably 10 to 150.) [ka] (wherein r is an integer of 1 to 6, preferably an integer of 2 to 4, and C r F 2r O may be linear or branched, s is an integer of 0 to 6, preferably an integer of 1 to 4, t is an integer of 1 to 100, preferably an integer of 5 to 80, u is an integer of 1 to 100, preferably an integer of 5 to 80, t+u is an integer of 2 to 200, preferably an integer of 10 to 150, s+t+u is an integer of 4 to 200, preferably an integer of 10 to 150, and v is an integer of 5 to 200, preferably an integer of 10 to 150.

[0020] Rf 2The most preferred example of Rf is the following structure: 2 The terminal part of Rf is highly reactive due to the electron-withdrawing property of the fluorine atom and is prone to hydrolysis. 2 If Rf has the following structure: 2 is particularly preferred because the terminal portion is blocked with a C2F4 group, more preferably a CF(CF3) group, making it less susceptible to hydrolysis and preventing decomposition even during long-term storage. [ka] (wherein r, s, t, u, and v are the same as above.)

[0021] In the above formula (1), R 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms, preferably 1 to 6. Specific examples of the monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, and octyl, cycloalkyl groups such as cyclohexyl, alkenyl groups such as vinyl, allyl, and propenyl, aryl groups such as phenyl, tolyl, and xylyl, and aralkyl groups such as benzyl and phenylethyl. 1 is preferably a hydrogen atom, a methyl group, or an ethyl group, and particularly preferably a hydrogen atom.

[0022] In the above formula (1), Y 2 are independently a (b'+1)-valent organic group having 1 to 20 carbon atoms, preferably 1 to 8, and are preferably a (b'+1)-valent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 8, which may contain an ether bond. 2 Particularly preferred structures include the following: [ka] (In the formula, * represents a bond bonded to N, and ** represents X 2 )

[0023] In the above formula (1), X 2 are independently monovalent organic groups containing an acrylic group or an α-substituted acrylic group, and contain on average at least one such acrylic group or α-substituted acrylic group per molecule.

[0024] X 2 As the alkyl group, a structure represented by the following formula is preferred. [ka] (In the formula, R 2 are independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; W is a single bond, or a divalent or trivalent hydrocarbon group which may contain one or more bonds selected from an ether bond, an ester bond, and a urethane bond; and n is 1 or 2.

[0025] In the above formula, W is a single bond or a divalent or trivalent hydrocarbon group which may contain one or more bonds selected from an ether bond, an ester bond, and a urethane bond. Examples of the divalent or trivalent hydrocarbon group include groups represented by the following formula: [ka] (where * represents Y in general formula (1) 2 is the bond to the oxygen atom, and ** is the bond to the oxygen atom.)

[0026] X 2 As the alkyl group, a structure represented by the following formula is more preferred. [ka]

[0027] In the above formula (1), V 2 is a hydrogen atom, a fluorine atom, or -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a and preferably -C(=O)-NR1 a [Y 2 (X 2 ) b’ ] 2-a It is a monovalent group represented by the formula: V 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a When the compound is a monovalent group represented by the formula (V), it contains an average of at least two acrylic groups or α-substituted acrylic groups per molecule, so that a composition using the compound forms a mesh-like network, and a cured product having excellent mechanical properties can be obtained. 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a When the monovalent group is a monovalent group represented by 1 , Y 2 , X 2 , b', and a may be the same or different.

[0028] In the above formula (1), a is 0 or 1, and is preferably 1. In the above formula (1), b' is an integer of 1 to 10, and is preferably 1 or 2.

[0029] The fluoropolyether group-containing acrylic compound represented by the above formula (1) is preferably one represented by the following formula: [ka] (In the formula, X 2 , q, r, s, t, u are the same as above.)

[0030] As the fluoropolyether group-containing acrylic compound represented by the above formula (1), the compound represented by the following formula is particularly preferred. [ka] (In the formula, X 2 , r, s, t, u are the same as above.)

[0031] In the fluoropolyether group-containing acrylic compound represented by the general formula (1), for example, V 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a A monovalent group represented by the following general formula (2): Rf 2 [C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a ]2(2) (In the formula, Rf 2 , R 1 , Y 2 , X 2 , a, b' are the same as above.) A suitable method for synthesizing a fluoropolyether group-containing acrylic compound represented by the following general formula (3) is, for example, Rf 2 [C(=O)-X 3 ]2(3) (In the formula, Rf 2 is the same as above, and X 3 is a halogen atom or an unsubstituted or fluorine-substituted alkoxy group. The fluoropolyether group-containing compound having an acid halide or ester at the molecular chain terminal, represented by the following general formula (4), H-NR 1 a [Y 2 [OH] b’ ] 2-a (4) (In the formula, R 1 , Y 2 , a, b' are the same as above.) An intermediate fluoropolyether group-containing alcohol compound is obtained by amidating an amino alcohol compound represented by the following formula:

[0032] Here, X in the above formula (3) 3 is a halogen atom, or an unsubstituted or fluorine-substituted alkoxy group preferably having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms. Specific examples include halogen atoms such as fluorine, chlorine, and bromine; alkoxy groups such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, hexyloxy, and octyloxy; and fluorine-substituted alkoxy groups in which some or all of the hydrogen atoms in these groups have been substituted with fluorine atoms, such as a trifluoromethoxy group, a 2,2,2-trifluoroethoxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group.

[0033] Specific examples of the fluoropolyether group-containing compound having an acid halide or ester at the molecular chain terminal, represented by the above formula (3), include the compounds shown below. Rf 2 [C(=O)-Cl]2 Rf 2 [C(=O)-F]2 Rf 2 [C(=O)-O-CH3]2 Rf 2 [C(=O)-O-C2H5]2 Rf 2 [C(=O)-O-C3H7]2 Rf 2 [C(=O)-O-C4H9]2 Rf 2 [C(=O)-O-CH 11 ]2 Rf 2 [C(=O)-O-CH 13 ]2 Rf 2 [C(=O)-O-CF3]2 Rf 2 [C(=O)-O-C2F5]2 Rf 2 [C(=O)-O-CH(CF3)2]2 (In the formula, Rf 2 is the same as above.)

[0034] Examples of the amino alcohol compound represented by the above formula (4) include the compounds shown below. [ka] [ka] [ka] [ka]

[0035] The reaction ratio of the fluoropolyether group-containing compound having an acid halide or ester at the molecular chain terminal represented by formula (3) with the amino alcohol compound represented by formula (4) is preferably 1 to 12 times, and more preferably 1.2 to 6 times, the molar amount of the amino alcohol compound represented by formula (4) relative to the total number of moles of the acid halide or ester groups in the fluoropolyether group-containing compound having an acid halide or ester at the molecular chain terminal represented by formula (3). If the amount of the amino alcohol compound represented by formula (4) is less than this, it may be difficult to obtain the desired fluoropolyether group-containing alcohol compound.

[0036] This amidation reaction is carried out by mixing a fluoropolyether group-containing compound having an acid halide or ester at the molecular chain terminal, represented by formula (3), with an amino alcohol compound represented by formula (4), and carrying out the reaction at a reaction temperature of 0 to 100°C, preferably 0 to 80°C, for 1 minute to 48 hours, and particularly 10 minutes to 12 hours. If the reaction temperature is too low, the reaction may stop before proceeding sufficiently, while if the reaction temperature is too high, undesired side reactions or decomposition of the raw materials may occur.

[0037] The amidation reaction can be carried out in the absence of a solvent, but may be diluted with a solvent if necessary. In this case, any commonly used organic solvent can be used as the dilution solvent, but it is preferable to use one whose boiling point is equal to or higher than the target reaction temperature and which does not inhibit the reaction. Examples of such solvents include partially fluorinated solvents, such as fluorinated aromatic hydrocarbon solvents (e.g., m-xylene hexafluoride, benzotrifluoride, etc.) and fluorinated ether solvents (e.g., methyl perfluorobutyl ether, etc.), with m-xylene hexafluoride being particularly preferred. When a solvent is used, the amount used is preferably 5 to 2,000 parts by mass, more preferably 50 to 500 parts by mass, relative to 100 parts by mass of the fluoropolyether group-containing compound having an acid halide or ester at the molecular chain terminal, as represented by formula (3). If the amount is less than this, the effect of dilution by the solvent becomes weak, and if the amount is more, the degree of dilution becomes too high, which may lead to a decrease in the reaction rate.

[0038] After the reaction is completed, it is preferable to remove the unreacted amino alcohol compound represented by formula (4) and the dilution solvent by a known method such as vacuum distillation, extraction, or adsorption.

[0039] In this way, by subjecting a fluoropolyether group-containing compound having an acid halide or ester at the molecular chain terminal represented by general formula (3) to an amidation reaction with an amino alcohol compound represented by general formula (4), a fluoropolyether group-containing alcohol compound represented by the following general formula (5) can be obtained. Rf 2 [C(=O)-NR 1 a [Y 2 [OH] b’ ] 2-a ]2(5) (In the formula, Rf 2 , R 1 , Y 2 , a, b' are the same as above.)

[0040] Examples of such fluoropolyether group-containing alcohol compounds represented by formula (5) include those shown below. [ka] [ka] [ka] [ka] (In the formula, Rf 2 is the same as above.)

[0041] Next, by introducing a (meth)acrylic group into the fluoropolyether group-containing alcohol compound represented by formula (5) obtained above, the desired fluoropolyether group-containing acrylic compound represented by formula (2) can be obtained.

[0042] A method for introducing a (meth)acrylic group into a fluoropolyether group-containing alcohol compound represented by formula (5) includes reacting the fluoropolyether group-containing alcohol compound represented by formula (5) with an isocyanate compound containing a (meth)acrylic group.

[0043] Examples of the isocyanate compound containing a (meth)acrylic group include the following. [ka]

[0044] The isocyanate compound containing (meth)acrylic groups may be charged in an amount equal to or greater than the total amount of hydroxyl groups in the fluoropolyether group-containing alcohol compound and reacted to react all of the hydroxyl groups. Alternatively, an average of 1 mole or more of (meth)acrylic groups may be introduced per mole of the fluoropolyether group-containing alcohol compound. By using an excess of hydroxyl groups, it is possible to prevent unreacted isocyanate compounds containing (meth)acrylic groups from remaining. Specifically, if the amount of fluoropolyether group-containing alcohol compounds in the reaction system is x moles and the total amount of hydroxyl groups in the fluoropolyether group-containing alcohol compounds is y moles, the amount of isocyanate compounds containing (meth)acrylic groups is preferably at least x moles but not more than 2y moles, and particularly preferably at least x moles but not more than 0.6y moles but not more than 1.4y moles. If the amount is too small, there is a high possibility that fluoropolyether group-containing alcohol compounds without any (meth)acrylic groups will remain. If the amount is too large, it becomes difficult to remove unreacted isocyanate compounds containing (meth)acrylic groups.

[0045] In addition, during the reaction, the reaction may be carried out by diluting with an appropriate solvent as needed. Such a solvent can be used without any particular limitation as long as it does not react with the hydroxyl group of the fluoropolyether group-containing alcohol compound or the isocyanate group of the isocyanate compound containing a (meth)acrylic group. Specific examples include hydrocarbon solvents such as toluene, xylene, and isooctane; ether solvents such as tetrahydrofuran (THF), diisopropyl ether, and dibutyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, and cyclohexanone; fluorine-modified aromatic hydrocarbon solvents such as m-xylene hexafluoride (also known as hexafluorometa-xylene) and benzotrifluoride; and fluorine-modified ether solvents such as methyl perfluorobutyl ether. After the reaction, the solvent may be removed by a known method such as vacuum distillation, or may be used as a diluted solution as is depending on the intended use. The amount of solvent used is not particularly limited, but is preferably 10 times or less the total mass of all the reaction components. If the amount of solvent used is too large, the reaction rate may decrease significantly.

[0046] Furthermore, during the reaction, a polymerization inhibitor may be added as necessary. There are no particular limitations on the polymerization inhibitor, but those typically used as polymerization inhibitors for acrylic compounds can be used. Specific examples include hydroquinone, hydroquinone monomethyl ether, 4-tert-butylcatechol, and dibutylhydroxytoluene. The amount of polymerization inhibitor used can be determined based on the reaction conditions, post-reaction purification conditions, and final use conditions, and is not particularly limited, but is usually 0.01 to 5,000 ppm, particularly preferably 0.1 to 500 ppm, based on the total mass of the reaction components.

[0047] During the reaction, a suitable catalyst may be added to increase the reaction rate. Examples of the catalyst include alkyltin ester compounds such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctoate, dioctyltin diacetate, dioctyltin dilaurate, dioctyltin dioctate, and stannous dioctanoate; titanate esters or titanium chelate compounds such as tetraisopropoxytitanium, tetra-n-butoxytitanium, tetrakis(2-ethylhexoxy)titanium [also known as tetrakis(2-ethylhexyl) orthotitanate], dipropoxybis(acetylacetonate)titanium, and titanium isopropoxyoctylene glycol; zirconium tetraacetylacetonate, zirconium tributoxymonoacetylacetonate, zirconium monobutoxyacetylacetonate bis(ethylacetoacetate), zirconium dibutoxybis(ethylacetoacetate), zirconium tetraacetylacetonate, zirconium chelate, and bismuth carboxylate compounds. These compounds are not limited to one type, and can be used as a mixture of two or more types. However, titanium compounds and bismuth compounds are particularly preferred in terms of toxicity and reactivity. The reaction rate can be increased by adding these catalysts in an amount of 0.01 to 2 mass %, preferably 0.05 to 1 mass %, based on the total mass of the reaction components.

[0048] The reaction is carried out at a temperature of 0 to 120°C, preferably 10 to 100°C, for 1 minute to 500 hours, preferably 10 minutes to 48 hours. If the reaction temperature is too low, the reaction rate may be too slow, whereas if the reaction temperature is too high, polymerization of the (meth)acrylic group may occur as a side reaction.

[0049] After the reaction is completed, the unreacted isocyanate compound and the solvent are removed by distillation, adsorption, filtration, washing or other methods, to obtain the fluoropolyether group-containing acrylic compound represented by the above formula (2).

[0050] Furthermore, when the reaction is stopped, an alcohol compound such as methanol or ethanol may be added to the system to form a urethane bond with the unreacted isocyanate compound. The urethane (meth)acrylates formed can be removed in the same manner as the unreacted isocyanate compound, but they can also be used as they remain.

[0051] Another method for introducing a (meth)acrylic group into a fluoropolyether group-containing alcohol compound represented by formula (5) is to react the fluoropolyether group-containing alcohol compound represented by formula (5) with a (meth)acrylic acid halide to form an ester.

[0052] Examples of the (meth)acrylic acid halide include the following. [ka] (wherein X is a halogen atom such as fluorine, chlorine, or bromine.) Acrylic acid chloride and methacrylic acid chloride are particularly preferred.

[0053] It is desirable to charge and react (meth)acrylic acid halide in an amount equal to or greater than the total amount of hydroxyl groups in the fluoropolyether group-containing alcohol compound, so that all of the hydroxyl groups are reacted. Specifically, it is desirable to use 1 to 6 times, and particularly 1.2 to 4 times, the amount of (meth)acrylic acid halide in the reaction system relative to the amount of hydroxyl groups in the fluoropolyether group-containing alcohol compound. If the amount is too small, there is a high possibility that some of the fluoropolyether group-containing alcohol compound will remain without (meth)acrylic groups introduced.

[0054] In the ester production reaction in which a fluoropolyether group-containing alcohol compound is reacted with a (meth)acrylic acid halide, it is preferable to use an acid acceptor, and the fluoropolyether group-containing alcohol compound represented by the above formula (5), the (meth)acrylic acid halide, and the acid acceptor are mixed and stirred. Examples of the acid acceptor that can be used include triethylamine, pyridine, and urea. The amount of acid acceptor used is preferably about 0.9 to 3 times the number of moles of (meth)acrylic acid halide. If the amount is too small, a large amount of untrapped acid remains, whereas if the amount is too large, it becomes difficult to remove the excess acid acceptor.

[0055] In addition, during the reaction, the reaction may be carried out by diluting with an appropriate solvent as needed. Such a solvent can be used without any particular limitation as long as it does not react with the hydroxyl group of the fluoropolyether group-containing alcohol compound or the halogen atom of the (meth)acrylic acid halide. Specific examples include hydrocarbon solvents such as toluene, xylene, and isooctane; ether solvents such as tetrahydrofuran (THF), diisopropyl ether, and dibutyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, and cyclohexanone; fluorine-modified aromatic hydrocarbon solvents such as m-xylene hexafluoride (also known as hexafluorometa-xylene) and benzotrifluoride; and fluorine-modified ether solvents such as methyl perfluorobutyl ether. The solvent may be removed by a known method such as vacuum distillation after the reaction, or may be used as a diluted solution as is depending on the intended use. The amount of solvent used is not particularly limited, but is preferably 10 times or less the total mass of all the reaction components. If the amount of solvent used is too large, the reaction rate may decrease significantly.

[0056] The reaction is carried out at a temperature of 0 to 120°C, preferably 10 to 100°C, for 1 minute to 500 hours, preferably 10 minutes to 48 hours. If the reaction temperature is too low, the reaction rate may be too slow, whereas if the reaction temperature is too high, polymerization of the (meth)acrylic group may occur as a side reaction.

[0057] After the reaction is completed, the unreacted (meth)acrylic acid halide and the solvent are removed by distillation, adsorption, filtration, washing, or other methods, to obtain the fluoropolyether group-containing acrylic compound represented by the above formula (2).

[0058] The refractive index of the fluoropolyether group-containing acrylic compound of the present invention at a temperature of 25°C and a wavelength of 589 nm is preferably 1.390 or less, more preferably 1.380 or less, and even more preferably 1.370 or less. When the compound has such a refractive index, it can form a cured product with a low refractive index that is useful for optical component applications. The refractive index can be measured using a refractometer such as an Abbe refractometer. In the present invention, in order to achieve a refractive index of 1.390 or less under the above conditions, the fluoropolyether group-containing acrylic compound needs to have a divalent perfluoropolyether group having a number average molecular weight of 500 to 40,000 and composed of a perfluoroalkylene group having 1 to 6 carbon atoms and an oxygen atom.

[0059] The fluoropolyether group-containing acrylic compound of the present invention obtained as described above has a perfluoropolyether group as a group having a low refractive index, an amide bond as a group improving compatibility with a photopolymerization initiator, and an acrylic group or an α-substituted acrylic group, so that it has a low refractive index and is compatible with a photopolymerization initiator to form a transparent composition.In addition, it can be used as a material for a fluorine-containing active energy curable composition that can be cured by active energy rays such as ultraviolet rays and electron beams. [Example]

[0060] The present invention will be specifically explained below by showing synthesis examples, synthesis comparison examples, examples, and comparative examples, but the present invention is not limited to the following examples. In the following examples, the number average molecular weight of the perfluoropolyether group is 19 The values ​​are calculated from the characteristic peak intensity ratio between the terminal structure and the main chain structure of the fluoropolyether group-containing acrylic compound based on F-NMR analysis.

[0061] [Synthesis Example 1] Synthesis of fluoropolyether group-containing acrylic compound (A-1) In a dry nitrogen atmosphere, a reaction vessel was charged with a compound having the following average structure: [ka] (Rf A1 Number average molecular weight: approx. 4,400 100 g (0.025 mol) of compound (I) represented by the following formula [ka] 12.2 g (0.20 mol) of compound (i) represented by the formula (I) and 100 g of m-xylene hexafluoride were charged and stirred at 60°C for 3 hours under a dry nitrogen atmosphere. IR analysis of the reaction solution confirmed the disappearance of the band derived from the -C(=O)F bond. The resulting reaction solution was washed with water and then distilled under reduced pressure to obtain 92.3 g of fluoropolyether group-containing alcohol compound (II) represented by the following structural formula. [ka] (Rf A1 Number average molecular weight: approx. 4,400

[0062] In a dry air atmosphere, 50.0 g (hydroxyl group amount 0.024 mol) of the fluoropolyether group-containing alcohol compound (II) obtained by the above method was mixed with 50.0 g of THF and 3.6 g (0.024 mol) of methacryloyloxyethyl isocyanate in a reaction vessel, and the mixture was heated to 50°C. 0.15 g of bismuth carboxylate catalyst (XK-640 manufactured by Kusumoto Chemicals) was added, and the mixture was stirred at 50°C for 24 hours. After heating, the mixture was evaporated under reduced pressure to obtain 46.3 g of a highly viscous liquid substance. 1 From the results of H-NMR and IR, it was confirmed that the compound was a fluoropolyether group-containing acrylic compound (A-1) represented by the following formula. [ka] (Rf A1 Number average molecular weight: approx. 4,400

[0063] [Synthesis Example 2] Synthesis of fluoropolyether group-containing acrylic compound (A-2) In a dry nitrogen atmosphere, a reaction vessel was charged with a compound having the following average structure: [ka] (Rf A2 Number average molecular weight: approx. 5,800 100 g (0.017 mol) of compound (III) represented by the following formula [ka] 8.5 g (0.14 mol) of compound (i) represented by the formula (I) and 100 g of m-xylene hexafluoride were charged and stirred at 65°C for 8 hours under a dry nitrogen atmosphere. IR analysis of the reaction solution confirmed the disappearance of the band derived from the -C(=O)F bond. The resulting reaction solution was washed with water and then distilled under reduced pressure to obtain 94.4 g of fluoropolyether group-containing alcohol compound (IV) represented by the following structural formula. [ka] (Rf A2 Number average molecular weight: approx. 5,800

[0064] In a dry air atmosphere, 50.0 g (hydroxyl group amount 0.017 mol) of the fluoropolyether group-containing alcohol compound (IV) obtained by the above method was mixed with 50.0 g of m-xylene hexafluoride, 3.6 g (0.034 mol) of methacrylic acid chloride, and 4.4 g (0.043 mol) of triethylamine in a reaction vessel, and the mixture was stirred for 24 hours at 50° C. After heating, the mixture was washed with water and then distilled under reduced pressure to obtain 39.9 g of a highly viscous liquid substance. 1 From the results of H-NMR and IR, it was confirmed that the compound was a fluoropolyether group-containing acrylic compound (A-2) represented by the following formula. [ka] (Rf A2 Number average molecular weight: approx. 5,800

[0065] [Synthesis Example 3] Synthesis of fluoropolyether group-containing acrylic compound (A-3) In a dry air atmosphere, 50.0 g (hydroxyl group amount 0.017 mol) of fluoropolyether group-containing alcohol compound (IV) obtained in the same manner as in Synthesis Example 2 was mixed with 50.0 g of THF and 2.6 g (0.017 mol) of methacryloyloxyethyl isocyanate in a reaction vessel, and the mixture was heated to 50°C. 0.15 g of bismuth carboxylate catalyst (XK-640 manufactured by Kusumoto Chemicals) was added thereto, and the mixture was stirred at 50°C for 24 hours. After heating, the mixture was distilled under reduced pressure to obtain 48.3 g of a liquid highly viscous substance. 1 From the results of H-NMR and IR, it was confirmed that the compound was a fluoropolyether group-containing acrylic compound (A-3) represented by the following formula. [ka] (Rf A2 Number average molecular weight: approx. 5,800

[0066] [Synthesis Example 4] Synthesis of fluoropolyether group-containing acrylic compound (A-4) In a dry air atmosphere, 50.0 g (hydroxyl group amount 0.017 mol) of fluoropolyether group-containing alcohol compound (IV) obtained in the same manner as in Synthesis Example 2 was mixed with 50.0 g of THF and 4.1 g (0.017 mol) of 1,1-(bisacryloyloxymethyl)ethyl isocyanate in a reaction vessel, and the mixture was heated to 50°C. 0.15 g of bismuth carboxylate catalyst (XK-640 manufactured by Kusumoto Chemicals) was added, and the mixture was stirred at 50°C for 24 hours. After heating, the mixture was evaporated under reduced pressure to obtain 37.3 g of a highly viscous liquid substance. 1 From the results of H-NMR and IR, it was confirmed that the compound was a fluoropolyether group-containing acrylic compound (A-4) represented by the following formula. [ka] (Rf A2 Number average molecular weight: approx. 5,800

[0067] [Synthesis Example 5] Synthesis of fluoropolyether group-containing acrylic compound (A-5) In a dry nitrogen atmosphere, a reaction vessel was charged with a compound having the following average structure: [ka] (Rf A3 Number average molecular weight: approx. 15,300 100 g (0.0063 mol) of compound (V) represented by the following formula [ka] 3.1 g (0.05 mol) of compound (i) represented by the formula (I) and 100 g of m-xylene hexafluoride were charged and stirred at 65°C for 8 hours under a dry nitrogen atmosphere. IR analysis of the reaction solution confirmed the disappearance of the band derived from the -C(=O)F bond. The resulting reaction solution was washed with water and then distilled under reduced pressure to obtain 73.2 g of fluoropolyether group-containing alcohol compound (VI) represented by the following structural formula. [ka] (Rf A3 Number average molecular weight: approx. 15,300

[0068] In a dry air atmosphere, 50.0 g of the fluoropolyether group-containing alcohol compound (VI) (hydroxyl group amount: 0.0063 mol) obtained by the above method was mixed with 50.0 g of THF and 0.98 g (0.0063 mol) of methacryloyloxyethyl isocyanate in a reaction vessel, and the mixture was heated to 50°C. 0.15 g of a bismuth carboxylate catalyst (XK-640 manufactured by Kusumoto Chemicals) was added, and the mixture was stirred at 50°C for 24 hours. After heating, the mixture was evaporated under reduced pressure to obtain 32.8 g of a highly viscous liquid substance. 1 From the results of H-NMR and IR, it was confirmed that the compound was a fluoropolyether group-containing acrylic compound (A-5) represented by the following formula. [ka] (Rf A3 Number average molecular weight: approx. 15,300

[0069] [Synthesis Example 6] Synthesis of fluoropolyether group-containing acrylic compound (A-6) In a dry nitrogen atmosphere, a reaction vessel was charged with a compound having the following average structure: [ka] (Rf A2 Number average molecular weight: approx. 5,800 100 g (0.017 mol) of compound (III) represented by the following formula [ka] 12.8 g (0.14 mol) of compound (ii) represented by the formula (II) and 100 g of m-xylene hexafluoride were charged and stirred at 65°C for 8 hours under a dry nitrogen atmosphere. IR analysis of the reaction solution confirmed the disappearance of the band derived from the -C(=O)F bond. The resulting reaction solution was washed with water and then distilled under reduced pressure to obtain 88.7 g of fluoropolyether group-containing alcohol compound (VII) represented by the following structural formula. [ka] (Rf A2Number average molecular weight: approx. 5,800

[0070] In a dry air atmosphere, 50.0 g (hydroxyl group amount 0.033 mol) of the fluoropolyether group-containing alcohol compound (VII) obtained by the above method was mixed with 50.0 g of THF and 5.1 g (0.033 mol) of methacryloyloxyethyl isocyanate in a reaction vessel, and the mixture was heated to 50° C. 0.15 g of bismuth carboxylate catalyst (XK-640 manufactured by Kusumoto Chemicals) was added thereto, and the mixture was stirred at 50° C. for 24 hours. After heating, the mixture was evaporated under reduced pressure to obtain 36.6 g of a liquid highly viscous substance. 1 From the results of H-NMR and IR, it was confirmed that the compound was a fluoropolyether group-containing acrylic compound (A-6) represented by the following formula. [ka] (Rf A2 Number average molecular weight: approx. 5,800

[0071] [Comparative Synthesis Example 1] Synthesis of fluoropolyether group-containing acrylic compound (A-7) In a dry nitrogen atmosphere, a reaction vessel was charged with a compound having the following average structure: [ka] (Rf A2 Number average molecular weight: approx. 5,800 100 g (0.017 mol) of compound (III) represented by the following formula [ka] 6.6 g (0.051 mol) of compound (iii) represented by the formula (2), 50.0 g of m-xylene hexafluoride, and 5.2 g (0.051 mol) of triethylamine were mixed and stirred for 24 hours at 50° C. After heating, the mixture was washed with water and then evaporated under reduced pressure to obtain 34.4 g of a highly viscous liquid substance. 1 From the results of H-NMR and IR, it was confirmed that the compound was a fluoropolyether group-containing acrylic compound (A-7) represented by the following formula. [ka] (Rf A2 Number average molecular weight: approx. 5,800

[0072] Evaluation of the refractive index of compounds The refractive index of the compound was measured using an Abbe refractometer (DR-A1 manufactured by Atago Co., Ltd.) at a temperature of 25° C. and a wavelength of 589 nm. The results are shown in Table 1.

[0073] [Table 1]

[0074] [Examples 1 to 6, Comparative Example 1] Evaluation of the compatibility of compounds with photoinitiators The fluoropolyether group-containing acrylic compounds (A-1) to (A-6) obtained in Synthesis Examples 1 to 6 above or the fluoropolyether group-containing acrylic compound (A-7) obtained in Synthesis Comparative Example 1 were mixed with a photopolymerization initiator (2-hydroxy-2-methylpropiophenone or 2-diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide) in the amounts shown below to obtain blended compositions. The appearance of the resulting blended compositions was visually observed and evaluated according to the following criteria. The results are shown in Table 2. Compound A: 100 parts by weight of a fluoropolyether group-containing acrylic compound and 1 part by weight of 2-hydroxy-2-methylpropiophenone ◯ (Good): The appearance of the blended composition of Blend A is uniform. × (bad): The appearance of the blended composition of Blend A is non-uniform. Compound B: 100 parts by weight of fluoropolyether group-containing acrylic compound and 1 part by weight of 2-diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide ◯ (Good): The appearance of the blended composition of Blend B is uniform. × (bad): The appearance of the blended composition of Blend B is non-uniform.

[0075] [Table 2]

[0076] The fluoropolyether group-containing acrylic compounds (A-1) to (A-6) of the present invention exhibit a low refractive index, and Examples 1 to 6, which used the fluoropolyether group-containing acrylic compounds (A-1) to (A-6) of the present invention, exhibited excellent compatibility with photopolymerization initiators. On the other hand, the fluoropolyether group-containing acrylic compound (A-7), which does not contain an amide bond in its structure, exhibited a low refractive index, but Comparative Example 1, which used the fluoropolyether group-containing acrylic compound (A-7), exhibited poor compatibility with photopolymerization initiators.

Claims

1. The following general formula (1) V 2 -Rf 2 -C(=O)-NR 1 a [Y 2 (X 2 ) b’ ] 2-a (1) (wherein, Rf 2 is a divalent perfluoropolyether group having a number average molecular weight of 2,000 to 40,000, which is composed of a perfluoroalkylene group having 1 to 6 carbon atoms and an oxygen atom, and both ends of which are perfluoroalkylene groups having 2 to 6 carbon atoms. 2 are independently hydrocarbon groups having 1 to 20 carbon atoms and a valence of (b'+1). 2 R is independently a monovalent organic group containing an acrylic group or an α-substituted acrylic group, and contains at least one acrylic group or α-substituted acrylic group on average per molecule. 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms. 2 is a hydrogen atom, a fluorine atom, or —C(═O)—NR 1 a [Y 2 (X 2 ) b’ ] 2-a a is 0 or 1, and b' is an integer from 1 to 10. and a photopolymerization initiator.

2. In general formula (1), Rf 2 is expressed as follows: 【Chemistry 1】 (In the formula, c is independently an integer of 2 to 6 for each unit; d, e, f, g, h, and i are each integers of 0 to 200, and d+e+f+g+h+i=4 to 200. Each of these units may be linear or branched, and each repeating unit shown in parentheses with d, e, f, g, h, and i may be bonded randomly.) 2. The fluorine-containing active energy ray-curable composition according to claim 1, wherein the divalent perfluoropolyether group is represented by the formula:

3. In general formula (1), Rf 2 is the following structural formula -CF 2 CF 2 O-(CF 2 CF 2 CF 2 O) q -CF 2 CF 2 - (In the formula, q is an integer of 4 to 200.) 【Chemistry 2】 (wherein r is an integer from 1 to 6, C r F 2r O may be linear or branched, s is an integer of 0 to 6, t and u are each an integer of 1 to 200, t+u is an integer of 2 to 200, and s+t+u is an integer of 4 to 200. v is an integer of 5 to 200.

2. The fluorine-containing active energy ray-curable composition according to claim 1, wherein the divalent perfluoropolyether group is selected from the group consisting of:

4. In general formula (1), R 1 2. The fluorine-containing active energy ray-curable composition according to claim 1, wherein is a hydrogen atom and a is 1.

5. In the general formula (1), Y 2 2. The fluorine-containing active energy ray-curable composition according to claim 1, wherein: 【Transformation 3】 (In the formula, * is a bond bonded to N, ** is X 2 is the bond that bonds with

6. In general formula (1), X 2 is the following structural formula 【Chemistry 4】 (In the formula, R 2 are independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; W is a single bond, or a divalent or trivalent hydrocarbon group which may contain one or more bonds selected from an ether bond, an ester bond, and a urethane bond; and n is 1 or 2.

2. The fluorine-containing active energy ray-curable composition according to claim 1, wherein the fluorine-containing active energy ray-curable composition is represented by the formula:

7. 2. The fluorine-containing active energy ray-curable composition according to claim 1, which does not contain a solvent.

8. The fluorine-containing active energy ray-curable composition according to any one of claims 1 to 7, wherein 100 parts by mass of the fluoropolyether group-containing acrylic compound and 1 part by mass of 2-hydroxy-2-methylpropiophenone or 2-diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide are mixed to form a blended composition having a uniform appearance.

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