Active energy ray-curable composition, and cured product and method for producing the same

Abstract

To provide an active energy ray-curable composition that enables formation of a cured product exhibiting superior strength (maximum stress) and / or superior elongation (elongation at break).SOLUTION: An active energy ray-curable composition includes a modified nanocellulose and an active energy ray-curable monomer, the modified nanocellulose comprising a nanocellulose and a modifying group introduced into the nanocellulose, wherein the modifying group is introduced into at least some carboxyl groups of the nanocellulose through ionic bonding and the modifying group includes an amino group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an active energy ray-curable composition, a cured product, and a method for producing the same. [Background technology]

[0002] Active energy ray-curable compositions that are cured by irradiation with active energy rays such as ultraviolet rays have a short curing time, are excellent in productivity, and are energy-saving, and therefore are used in a variety of applications such as printing inks, paints, electronic components, optical members, and building materials. However, cured products of active energy ray-curable compositions generally have the drawback of being brittle and lacking in toughness.

[0003] In recent years, nanocellulose has been proposed as an effective filler. Nanocellulose is a fine fiber made from cellulose, which is primarily derived from plants. Nanocellulose has attracted attention due to its extremely high crystalline modulus of elasticity, such as 100 GPa, and its low environmental impact. For example, Patent Document 1 discloses that a cured product of an active energy ray-curable composition containing nanocellulose and an active energy ray-curable monomer has excellent strength.

[0004] Furthermore, for example, Non-Patent Document 1 discloses that carboxy groups on the surface of cellulose nanofibers (CNF) oxidized with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) are modified with amines. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-11092 [Non-patent literature]

[0006] [Non-Patent Document 1] Cellulose. Vol. 29 (2022): 2839-2853 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide an active energy ray-curable composition capable of forming a cured product having excellent strength (maximum stress) and / or excellent elongation (elongation at break). [Means for solving the problem]

[0008] As a result of intensive research, the inventors have discovered that by combining modified nanocellulose with an active energy ray-curable monomer, a cured product with excellent strength and / or elongation can be formed.

[0009] The present invention includes the following embodiments. [1] Modified nanocellulose; an active energy ray-curable monomer; An active energy ray-curable composition comprising: The modified nanocellulose Nanocellulose and A modifying group introduced into the nanocellulose; Including, The modifying group is introduced into at least some of the carboxy groups of the nanocellulose via ionic bonds; the modifying group has an amino group; Active energy ray-curable composition. [2] The active energy ray-curable composition according to [1], wherein the nanocellulose contains an oxide of a cellulose-based raw material with hypochlorous acid or a salt thereof, and is substantially free of N-oxyl compounds. [3] The active energy ray-curable composition according to [1] or [2], wherein the ratio of the breaking elongation of a cured product obtained by curing the active energy ray-curable composition to the breaking elongation of a control cured product obtained by curing a control composition in which the modified nanocellulose is omitted from the active energy ray-curable composition is 0.6 or more. [4] The active energy ray-curable composition according to any one of [1] to [3], wherein the ratio of the maximum stress value of a cured product obtained by curing the active energy ray-curable composition to the maximum stress value of a control cured product obtained by curing a control composition in which the modified nanocellulose is omitted from the active energy ray-curable composition is 1.10 or more. [5] The active energy ray-curable composition according to any one of [1] to [4], wherein the ratio of the modulus of elasticity of a cured product obtained by curing the active energy ray-curable composition to the modulus of elasticity of a control cured product obtained by curing a control composition in which the modified nanocellulose is omitted from the active energy ray-curable composition is 1.00 or more. [6] The active energy ray-curable composition according to any one of [1] to [5], wherein the ratio of the work of fracture of a cured product obtained by curing the active energy ray-curable composition to the work of fracture of a control cured product obtained by curing a control composition in which the modified nanocellulose is omitted from the active energy ray-curable composition is 1.2 or more. [7] The active energy ray-curable composition according to any one of [1] to [6], wherein the modifying group is derived from a polyetheramine. [8] The active energy ray-curable composition according to any one of [1] to [7], wherein the average fiber width of the modified nanocellulose is 1 to 50 nm. [9] The active energy ray-curable composition according to any one of [1] to [8], wherein the average fiber length of the modified nanocellulose is 50 to 3000 nm.

[10] The active energy ray-curable composition according to any one of [1] to [9], further comprising a photopolymerization initiator.

[11] A cured product of the active energy ray-curable composition according to any one of [1] to

[10] .

[12] a step of irradiating the active energy ray-curable composition according to any one of [1] to

[10] with active energy rays to cure the composition; Including, Method for producing a cured product. [Effects of the Invention]

[0010] The present invention can provide an active energy ray-curable composition capable of forming a cured product having excellent strength and / or elongation. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows the relationship between the breaking elongation (%) and the maximum stress (kPa) of the sheet-like cured products obtained in the Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these and various modifications are possible without departing from the gist of the present invention.

[0013] As used herein, "(meth)acrylate" refers to acrylate and methacrylate. As used herein, "(meth)acryloyl" means acryloyl and methacryloyl. In this specification, "(meth)acrylic" means acrylic and methacrylic.

[0014] <Active energy ray-curable composition> One embodiment of the present invention is an active energy ray curable composition comprising modified nanocellulose and an active energy ray curable monomer, The modified nanocellulose comprises nanocellulose and a modifying group introduced into the nanocellulose; The modifying group is introduced into at least some of the carboxy groups of the nanocellulose via ionic bonds; The present invention relates to an active energy ray-curable composition, wherein the modifying group has an amino group.

[0015] The cured product formed from the active energy ray-curable composition according to this embodiment has excellent strength and / or elongation. The reason for this is presumed to be that the presence of the modifying group introduced into the nanocellulose prevents the modified nanocellulose from approaching each other, suppressing aggregation of the modified nanocellulose (i.e., improving the dispersibility of the modified nanocellulose), or that the modifying group ionizes in the organic solvent, causing a repulsive force between the modified nanocelluloses, suppressing aggregation of the modified nanocellulose. However, the present invention is not limited by these reasons.

[0016] [nature] A cured product of the active energy ray-curable composition preferably has the following properties when formed and measured under the following conditions.

[0017] (Formation of cured product) The active energy ray curable composition and the control composition were each poured into a 1 mm thick mold, and the integrated irradiance was 5000 mW / cm 2 The resin is irradiated with UV light so that a sheet-like cured product is formed. The control composition is a composition obtained by removing the modified nanocellulose from the active energy ray-curable composition. Therefore, the control composition can be prepared using the same types and amounts of components as the active energy ray-curable composition, except that the modified nanocellulose is not used. The target cured product is obtained by curing the target composition.

[0018] (Measurement of cured product) A rectangular test piece (thickness: approximately 1 mm) with a total length of 50 mm and a gauge width of 5 mm is cut from the sheet-like cured product. A tensile test is performed on this test piece using a tensile tester based on JIS K6251 at 23±2°C, a gauge length of 10 mm, and a tensile speed of 100 mm / min, to measure the breaking elongation, maximum stress, elastic modulus, and breaking work.

[0019] (Elongation at break) The ratio of the elongation at break of a cured product obtained by curing an active energy ray-curable composition to the elongation at break of a control cured product obtained by curing a control composition (hereinafter referred to as the "elongation at break ratio") is preferably 0.6 or more, more preferably 0.8 or more, even more preferably 1.0 or more, even more preferably 1.3 or more, and particularly preferably 1.6 or more. The upper limit of the elongation at break ratio is not particularly limited, and may be, for example, 4.0 or less, 3.5 or less, 3.2 or less, 3.0 or less, or 2.5 or less. The range of the elongation at break ratio can be determined by appropriately combining the above-mentioned upper and lower limits. The range of the elongation at break ratio may be, for example, 0.6 to 4.0, 0.8 to 3.5, 1.0 to 3.2, 1.3 to 3.0, or 1.5 to 2.5.

[0020] The elongation at break can be adjusted, for example, by changing the amount of modified nanocellulose. For example, increasing the amount of modified nanocellulose tends to increase the elongation at break.

[0021] (Maximum stress) The ratio of the maximum stress value of the cured product obtained by curing the active energy ray-curable composition to the maximum stress value of the control cured product obtained by curing the control composition (hereinafter referred to as the "maximum stress ratio") is preferably 1.10 or more, more preferably 1.15 or more, even more preferably 1.25 or more, even more preferably 1.50 or more, and particularly preferably 1.70 or more. The upper limit of the maximum stress ratio is not particularly limited, and may be, for example, 4.0 or less, 3.5 or less, 3.0 or less, 2.7 or less, or 2.5 or less. The range of the maximum stress ratio can be determined by appropriately combining the above-mentioned upper and lower limits. The range of the maximum stress ratio may be, for example, 1.10 to 4.0, 1.15 to 3.5, 1.25 to 3.0, 1.50 to 2.7, or 1.70 to 2.5.

[0022] The maximum stress can be adjusted, for example, by changing the amount of modified nanocellulose. For example, increasing the amount of modified nanocellulose tends to increase the maximum stress.

[0023] (elastic modulus) The ratio of the elastic modulus of a cured product obtained by curing an active energy ray-curable composition to the elastic modulus of a control cured product obtained by curing a control composition (hereinafter referred to as the "elastic modulus ratio") is preferably 1.00 or more, more preferably 1.05 or more, even more preferably 1.10 or more, even more preferably 1.40 or more, and particularly preferably 1.60 or more. The upper limit of the elastic modulus ratio is not particularly limited, and may be, for example, 4.0 or less, 3.5 or less, 3.0 or less, 2.5 or less, or 2.3 or less. The range of the elastic modulus ratio can be determined by appropriately combining the above-mentioned upper and lower limits. The range of the elastic modulus ratio may be, for example, 1.00 to 4.0, 1.05 to 3.5, 1.10 to 3.0, 1.40 to 2.5, or 1.60 to 2.3.

[0024] The modulus of elasticity tends to increase by decreasing the elongation at break and increasing the maximum stress.

[0025] (Work of Breaking) The ratio of the work of fracture of a cured product obtained by curing an active energy ray-curable composition to the work of fracture of a control cured product obtained by curing a control composition (hereinafter referred to as the "work of fracture ratio") is preferably 1.2 or more, more preferably 1.3 or more, even more preferably 1.5 or more, even more preferably 2.0 or more, and particularly preferably 2.5 or more. The upper limit of the work of fracture ratio is not particularly limited, and may be, for example, 5.0 or less, 4.5 or less, 4.0 or less, 3.5 or less, or 3.0 or less. The range of the work of fracture ratio can be determined by appropriately combining the above upper and lower limits. The range of the work of fracture ratio may be, for example, 1.2 to 5.0, 1.3 to 4.5, 1.5 to 4.0, 2.0 to 3.5, or 2.5 to 3.0.

[0026] The work of rupture tends to increase with increasing elongation at break and increasing maximum stress.

[0027] [Modified nanocellulose] The active energy ray-curable composition according to this embodiment contains modified nanocellulose. Modified nanocellulose is nanocellulose to which a modification group has been introduced. By using the modified nanocellulose, it is possible to form a cured product having excellent strength and / or elongation.

[0028] The amount of modified nanocellulose is preferably 0.1 to 20.0 mass%, more preferably 0.3 to 15.0 mass%, even more preferably 0.5 to 10.0 mass%, and still more preferably 0.5 to 7.0 mass%, based on the mass of the active energy ray-curable monomer.

[0029] Modified nanocellulose can be obtained, for example, by reacting nanocellulose with a modifying group-introducing compound described later. Nanocellulose is cellulose that has been nanosized. Nanocellulose can be obtained, for example, by oxidizing and nanoizing a cellulosic raw material. The order of oxidation and nanoization is not particularly limited, but it is preferable to oxidize the cellulosic raw material and then nanoize it. Nanoization tends to be easier by oxidizing the cellulosic raw material first.

[0030] Examples of oxidizing agents for oxidizing cellulosic raw materials include hypochlorous acid or its salts and N-oxyl compounds, such as 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).

[0031] From the viewpoint of forming a cured product with superior strength and / or elongation, it is preferable to use hypochlorous acid or a salt thereof as the oxidizing agent. That is, it is preferable that nanocellulose is obtained by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof (without using an N-oxyl compound) and nano-sizing the resulting oxidized cellulose.

[0032] The inventors have surprisingly found that when nanocellulose obtained using hypochlorous acid or its salts (without using an N-oxyl compound) is mixed with an active energy ray-curable monomer, a cured product with significantly superior strength and / or elongation can be formed, compared to when nanocellulose obtained by other methods (e.g., TEMPO oxidation) is mixed.

[0033] The following description focuses on the oxidation of cellulosic raw materials with hypochlorous acid or its salts, but nanocellulose is not limited to nanocellulose with hypochlorous acid or its salts.

[0034] [Oxidized cellulose] Unless otherwise specified, "oxidized cellulose" in this section hereinafter refers to an oxidation product of a cellulose-based raw material with hypochlorous acid or a salt thereof before defibration.

[0035] Examples of hypochlorous acid or salts thereof include hypochlorous acid water, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, and ammonium hypochlorite.

[0036] The amount of hypochlorous acid or its salt used is not particularly limited, but it is preferable to use it so that the available chlorine concentration in the reaction system is 6 to 43 mass %. The available chlorine concentration may be a low concentration of 6 to 14 mass %, or a high concentration of 14 to 43 mass %.

[0037] The definition of the effective chlorine concentration of hypochlorous acid or a salt thereof is as described in WO 2022 / 009979.

[0038] The cellulosic raw material is not particularly limited as long as it is a material primarily composed of cellulose, and examples thereof include pulp, natural cellulose, and fine cellulose obtained by depolymerizing cellulose through mechanical processing. The cellulosic raw material preferably has a type I crystal structure. As the cellulosic raw material, commercially available products such as crystalline cellulose made from pulp can be used as is. Alternatively, unused biomass containing a large amount of cellulose components, such as soybean pulp refuse or soybean hulls, may also be used as the raw material. Furthermore, the cellulosic raw material may be pre-treated with an alkali of an appropriate concentration in order to facilitate the penetration of the oxidizing agent used into the raw pulp. The main component of plants is cellulose, and bundles of cellulose molecules are called cellulose microfibrils. The cellulose in cellulosic raw materials is also contained in the form of cellulose microfibrils.

[0039] (N-oxyl compounds) Preferably, oxidized cellulose is substantially free of N-oxyl compounds. By being substantially free of N-oxyl compounds, the impact on the environment and human body is sufficiently reduced, resulting in a high level of safety. Examples of N-oxyl compounds include 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).

[0040] As used herein, "substantially free of N-oxyl compounds" means that no N-oxyl compounds are used in the production of oxidized cellulose, that the oxidized cellulose contains no N-oxyl compounds at all, or that the content of N-oxyl compounds is 2.0 ppm by mass or less, and preferably 1.0 ppm by mass or less, relative to the total amount of oxidized cellulose. In addition, when the content of N-oxyl compounds is, as an increase from the cellulosic raw material, preferably 2.0 mass ppm or less, more preferably 1.0 mass ppm or less, it is also considered to be "substantially free of N-oxyl compounds."

[0041] The content of N-oxyl compounds can be measured by known means, such as a method using a trace total nitrogen analyzer (for example, TN-2100H manufactured by Nitto Seiko Analytech Co., Ltd.).

[0042] (carboxyl group amount) The amount of carboxy groups in the oxidized cellulose is preferably 0.1 to 3.0 mmol / g, more preferably 0.2 to 2.0 mmol / g, even more preferably 0.3 to 1.5 mmol / g, particularly preferably 0.4 to 1.2 mmol / g, and most preferably 0.5 to 0.9 mmol / g.

[0043] The amount of carboxy groups in oxidized cellulose can be measured by the method described in WO 2022 / 009979.

[0044] Oxidized cellulose preferably has a structure in which at least two of the hydroxyl groups on the glucopyranose ring that constitutes cellulose are oxidized, and more specifically, it preferably has a structure in which the hydroxyl groups at the second and third positions on the glucopyranose ring are oxidized and dicarboxyl groups are introduced. It is also preferable that the hydroxyl group at the sixth position on the glucopyranose ring is not oxidized and remains as a hydroxyl group. The position of the carboxyl group on the glucopyranose ring is determined by the solid 13 It can be analyzed by C-NMR spectroscopy.

[0045] Rayon has the same chemical structure as cellulose, and its oxide (rayon oxide) is water-soluble. 13 By C-NMR measurement, a carbon peak attributable to the carboxy group is observed at 165 to 185 ppm. In one embodiment of the oxidation of a cellulosic raw material with hypochlorous acid or its salt, two signals appear in this chemical shift range. Furthermore, by solution two-dimensional NMR measurement, it can be determined that the carboxy groups are introduced at the 2- and 3-positions.

[0046] Solid oxide of cellulosic raw materials with hypochlorous acid or its salts 13 In C-NMR, when the amount of carboxyl groups introduced is large, two signals appear at 165 to 185 ppm, and when the amount of carboxyl groups introduced is small, a very broad signal may appear. As can be seen from the results for oxidized rayon, the signals of the carboxyl group carbons introduced at the 2nd and 3rd positions are close to each other, and this is difficult to achieve with low-resolution solid state spectroscopy. 13 In C-NMR, the separation of the two signals is insufficient. Therefore, when the amount of carboxyl group introduced is small, a broad signal is observed. 13 In the C-NMR spectrum, the introduction of carboxy groups at the 2nd and 3rd positions can be confirmed by evaluating the broadening of the peaks appearing at 165 to 185 ppm.

[0047] That is, solid 13A baseline is drawn around the peak in the range of 165 ppm to 185 ppm in the C-NMR spectrum to determine the overall area value, and then the area value is vertically divided at the peak top to determine the ratio of the two peak area values ​​(large area value / small area value). If the ratio of the peak area values ​​is 1.2 or more, the peak can be said to be broad. The presence or absence of the broad peak can be determined by the ratio of the length L of the baseline in the range of 165 ppm to 185 ppm to the length L' of the perpendicular line from the peak top to the baseline. That is, if the ratio L' / L is 0.1 or more, it can be determined that a broad peak is present. The ratio L' / L may be 0.2 or more, 0.3 or more, 0.4 or more, or even 0.5 or more. There is no particular upper limit to the ratio L' / L, but it is usually 3.0 or less, and may be 2.0 or less, or 1.0 or less.

[0048] The structure of the glucopyranose ring can also be determined by analysis according to the method described in Sustainable Chem. Eng. 2020, 8, 48, 17800-17806.

[0049] (Viscosity average degree of polymerization) The viscosity average degree of polymerization of the oxidized cellulose is preferably 30-500, more preferably 60-300, even more preferably 70-150, and particularly preferably 80-130.

[0050] The viscosity average degree of polymerization is the average degree of polymerization measured by a viscosity method. The viscosity average degree of polymerization can be measured by the method described in WO 2022 / 009979.

[0051] [Method of producing oxidized cellulose] Oxidized cellulose can be produced by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof. Specific production methods include those described in WO 2022 / 009979 and WO 2022 / 009980. Oxidized cellulose is also available commercially, such as Aronfibro (registered trademark) manufactured by Toagosei Co., Ltd.

[0052] [Nanocellulose] Unless otherwise specified, "nanocellulose" in this section hereinafter refers to an oxide of a cellulose-based raw material with hypochlorous acid or its salt, after defibration.

[0053] Nanocellulose is a general term for micronized cellulose, and includes micronized cellulose fibers and cellulose nanocrystals. Micronized cellulose fibers are also called cellulose nanofibers (also referred to as CNF).

[0054] Nanocellulose preferably has a carboxyl group. The carboxyl group may be in the H type (-COOH) or in the salt type. The type of salt is not particularly limited, but examples include alkali metal salts such as lithium salt, sodium salt, and potassium salt; alkaline earth metal salts such as calcium salt and barium salt; other metal salts such as magnesium salt and aluminum salt; ammonium salt; and organic amine salts. From the viewpoint of improving dispersibility in active energy ray-curable monomers, the carboxyl group is preferably of H type.

[0055] Nanocellulose is a collection of individual fibers. When nanocellulose contains carboxylated nanocellulose, it is sufficient that it contains at least one carboxylated nanocellulose, and it is preferable that carboxylated nanocellulose is the main component. Here, carboxylated nanocellulose being the main component means that the proportion of carboxylated nanocellulose in the total amount of nanocellulose exceeds 50% by mass, preferably exceeds 70% by mass, and more preferably exceeds 80% by mass. The upper limit of the above proportion is 100% by mass, but it may also be 98% by mass or 95% by mass.

[0056] (N-oxyl compounds) It is preferable that nanocellulose is substantially free of N-oxyl compounds. The meaning of "substantially free of N-oxyl compounds" and the method for measuring the content of N-oxyl compounds are as described in the above [Oxidized Cellulose] (N-oxyl Compounds) section.

[0057] (carboxyl group amount) The amount of carboxyl groups in nanocellulose and the method for measuring it shall follow the description in the (Carboxy group amount) section of [Oxidized cellulose] above.

[0058] (average fiber length) The average fiber length of nanocellulose is preferably 50 to 3000 nm, more preferably 50 to 700 nm, even more preferably 50 to 500 nm, still more preferably 60 to 300 nm, and particularly preferably 70 to 200 nm.

[0059] (average fiber width) The average fiber width of nanocellulose is preferably 1 to 20 nm, more preferably 1 to 15 nm, even more preferably 1 to 10 nm, and particularly preferably 1 to 5 nm.

[0060] The average fiber length and average fiber width of nanocellulose can be measured by the method described in WO 2022 / 009980.

[0061] (aspect ratio) The aspect ratio of nanocellulose (average fiber length / average fiber width) is preferably 20-1000, more preferably 20-200, even more preferably 30-190, and particularly preferably 40-180.

[0062] The average fiber length, average fiber width, and aspect ratio of the modified nanocellulose are preferably in the same range as those of the nanocellulose. The average fiber length, average fiber width, and aspect ratio of the modified nanocellulose can also be measured in accordance with the description of WO 2022 / 009980, as in the measurement of nanocellulose.

[0063] (zeta potential) The zeta potential of nanocellulose is preferably -30 mV or less, more preferably -90 mV or more and -30 mV or less, even more preferably -80 mV or more and -30 mV or less, even more preferably -70 mV or more and -30 mV or less, and particularly preferably -65 mV or more and -35 mV or less.

[0064] The zeta potential can be measured by the method described in WO 2022 / 009980.

[0065] (crystallinity) The crystallinity of the nanocellulose is preferably 10 to 70%, more preferably 20 to 70%, even more preferably 30 to 65%, particularly preferably 40 to 60%, and most preferably 50 to 55%.

[0066] Crystallinity was measured using solid nanocellulose for freeze-dried nanocellulose. 13C-NMR measurement can be performed and calculated from the peak of the fourth carbon (C4) of nanocellulose. Specifically, the C4 peak appears in the range of about 80 to 95 ppm, with the peaks of the crystalline portion (high ppm side, about 85 to 95 ppm) and the amorphous portion (low ppm side) overlapping, so the area of ​​each peak can be divided by the vertical division method and determined from the following formula. A more specific measurement method is as described in WO 2022 / 138759. Crystallinity=SC / (SC+SA)×100 [In the formula, SC is the crystalline portion, and SA is the amorphous portion.]

[0067] [Method of manufacturing nanocellulose] Nanocellulose can be produced by defibrating the above-mentioned oxidized cellulose. Specific production methods include those described in International Publication Nos. 2022 / 009979 and 2022 / 009980. Nanocellulose can also be obtained by defibrating commercially available oxidized cellulose (e.g., Aronfibro (registered trademark) manufactured by Toagosei Co., Ltd.).

[0068] [Modifying group] The modified nanocellulose has a modifying group introduced into at least some of the carboxyl groups of the nanocellulose. The bond between the modifying group and the nanocellulose is an ionic bond.

[0069] The modifying group has an amino group. Preferably, an ionic bond is formed between the amino group of the modifying group and a carboxy group of the nanocellulose. The amino group of the modifying group may be in the form of an ammonium ion.

[0070] The modifying group may be of one type or of multiple types.

[0071] The modifying group can be introduced by reacting nanocellulose having a carboxy group with a modifying group-introducing compound having an amino group. The modifying group can also be expressed as a modifying group-introducing compound that is ionically bonded to the carboxy group of nanocellulose. The modifying group-introducing compound will be described below, but the modifying group may have the same structure as the modifying group-introducing compound, except for the ionic bond with nanocellulose.

[0072] (Modifying group-introduced compound) The modifying group-introducing compound is a compound that reacts with nanocellulose to introduce a modifying group into the carboxyl group of the nanocellulose. The modifying group-introducing compound has an amino group.

[0073] The number of amino groups per molecule is, for example, 1 to 4, 1 to 3, 1 or 2, or 1.

[0074] The modifying group-introducing compound preferably has a long-chain linear or long-chain branched structure. The amino group is preferably located at a terminal of the molecule. The amino group may be located at only one terminal of the molecule, at multiple terminals of the molecule, or at all terminals of the molecule.

[0075] The modifying group-introducing compound preferably has an oxyalkylene group, more preferably has a plurality of oxyalkylene groups (polyoxyalkylene groups). In this specification, a compound having an amino group and a polyoxyalkylene group is referred to as a polyetheramine.

[0076] The oxyalkylene group is preferably an oxyalkylene group having 1 to 6 carbon atoms, more preferably an oxyalkylene group having 2 to 4 carbon atoms, and even more preferably an oxyalkylene group having 2 or 3 carbon atoms.

[0077] The oxyalkylene group preferably contains at least one selected from the group consisting of an oxyethylene group, an oxypropylene group, and an oxybutylene group, and more preferably contains an oxyethylene group and / or an oxypropylene group.

[0078] The number of repeating units of the oxyalkylene group is preferably 5-70, more preferably 10-50, and even more preferably 20-45.

[0079] From the viewpoint of further improving the strength and / or elongation of the cured product, the weight-average molecular weight of the modifying group-introduced compound is preferably 200 to 5000, more preferably 300 to 4000, and even more preferably 400 to 2500. The weight-average molecular weight can be measured by gel permeation chromatography (GPC).

[0080] The amount of the modifying group-introducing compound used is preferably 0.5 to 2.0 equivalents, more preferably 0.7 to 1.5 equivalents, and even more preferably 0.9 to 1.1 equivalents relative to the amount (mol) of carboxy groups in nanocellulose.

[0081] [Active energy ray curable monomer] The active energy ray-curable composition according to this embodiment contains an active energy ray-curable monomer. The active energy ray-curable monomer may be any monomer that can be cured by irradiation with active energy rays.

[0082] The active energy ray-curable monomer is preferably a compound having an ethylenically unsaturated group, such as a (meth)acryloyl group, a vinyl group, or a vinyl ether group.

[0083] The compound having an ethylenically unsaturated group may further have a hydrogen-bonding group in addition to the ethylenically unsaturated group. Examples of the hydrogen-bonding group include a hydroxyl group, a carboxyl group, an amide group, a carbamate group, an imide group, and a urea group.

[0084] (Compounds having a hydroxyl group and an ethylenically unsaturated group) Examples of compounds having a hydroxyl group and an ethylenically unsaturated group include hydroxyl group-containing (meth)acrylates.

[0085] Examples of hydroxyl group-containing (meth)acrylates include the following compounds (note that in compounds where the position of the hydroxy group is not specified, the substitution position of the hydroxy group is arbitrary).

[0086] Hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, hydroxyhexyl (meth)acrylate, and hydroxyoctyl (meth)acrylate.

[0087] Glycol mono(meth)acrylates such as ethylene glycol mono(meth)acrylate, propylene glycol mono(meth)acrylate, butanediol mono(meth)acrylate, pentanediol mono(meth)acrylate, and hexanediol mono(meth)acrylate.

[0088] Polyalkylene glycol mono(meth)acrylates such as diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, tripropylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate.

[0089] Polyol mono(meth)acrylates such as trimethylolpropane mono(meth)acrylate, glycerin mono(meth)acrylate, pentaerythritol mono(meth)acrylate, ditrimethylolpropane mono(meth)acrylate, and dipentaerythritol mono(meth)acrylate.

[0090] (Compounds having a carboxy group and an ethylenically unsaturated group) Examples of compounds having a carboxy group and an ethylenically unsaturated group include carboxy group-containing (meth)acrylates.

[0091] Examples of carboxy group-containing (meth)acrylates include (meth)acrylic acid, polycaprolactone-modified (meth)acrylic acid, Michael addition type polymers of (meth)acrylic acid, adducts of 2-hydroxyethyl (meth)acrylate and phthalic anhydride, and adducts of 2-hydroxyethyl (meth)acrylate and succinic anhydride.

[0092] (Compounds having an amide group and an ethylenically unsaturated group) Examples of compounds having an amide group and an ethylenically unsaturated group include N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, and (meth)acrylamide compounds.

[0093] Examples of the (meth)acrylamide-based compound include the following compounds:

[0094] N-alkylacrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nt-butyl(meth)acrylamide.

[0095] N,N-dialkylacrylamides such as N,N-dimethyl(meth)acrylamide and N,N-diethyl(meth)acrylamide.

[0096] N-hydroxyalkyl(meth)acrylamides such as N-hydroxyethyl(meth)acrylamide and N-methylol(meth)acrylamide.

[0097] N-alkoxyalkyl (meth)acrylamides such as N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, and N-methoxyethyl (meth)acrylamide.

[0098] (Meth)acryloylmorpholine.

[0099] (Compounds having a carbamate group and an ethylenically unsaturated group) Examples of compounds having a carbamate group and an ethylenically unsaturated group include (meth)acrylates having an oxazolidone group.

[0100] An example of a (meth)acrylate having an oxazolidone group is 2-(2-oxo-3-oxazolidinyl)ethyl (meth)acrylate.

[0101] (Compounds having an imide group and an ethylenically unsaturated group) An example of the compound having an imide group and an ethylenically unsaturated group is a compound having a maleimide group.

[0102] Examples of compounds having a maleimide group include (meth)acrylates having a hexahydrophthalimide group and (meth)acrylates having a tetrahydrophthalimide group.

[0103] An example of a (meth)acrylate having a hexahydrophthalimide group is N-(meth)acryloyloxyethylhexahydrophthalimide.

[0104] An example of a (meth)acrylate having a tetrahydrophthalimide group is N-(meth)acryloyloxyethyltetrahydrophthalimide.

[0105] (urethane (meth)acrylate) The active energy ray-curable monomer may be a compound having two or more ethylenically unsaturated groups. Examples of such compounds include a compound having a urethane bond and two or more (meth)acryloyl groups (hereinafter also referred to as "urethane (meth)acrylate").

[0106] Examples of urethane (meth)acrylates include reaction products of polyol, organic polyisocyanate, and hydroxyl group-containing (meth)acrylate; and reaction products of organic polyisocyanate and hydroxyl group-containing (meth)acrylate.

[0107] {Polyol} Examples of polyols include low molecular weight diols, diols having a polyester skeleton, diols having a polyether skeleton, and diols having a polycarbonate skeleton.

[0108] Low molecular weight diols include, for example, ethylene glycol, propylene glycol, cyclohexanedimethanol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol.

[0109] Examples of diols having a polyester skeleton include esterification reaction products of a diol component (such as the low-molecular-weight diols described above or polycaprolactone diol) and an acid component (such as a dicarboxylic acid or an anhydride thereof). Dicarboxylic acids or anhydrides thereof include, for example, adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and terephthalic acid, and anhydrides thereof.

[0110] Examples of diols having a polyether skeleton include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0111] Examples of diols having a polycarbonate skeleton include reaction products of diol components (such as the low-molecular-weight diols or bisphenols) with dialkyl carbonates (such as ethylene carbonate and dibutyl carbonate).

[0112] {Organic polyisocyanate} Examples of organic polyisocyanates include aliphatic polyisocyanates that do not have an alicyclic group (hereinafter also referred to as "aliphatic polyisocyanates"), aliphatic polyisocyanates that have an alicyclic group (hereinafter also referred to as "alicyclic polyisocyanates"), polyisocyanates that have a heterocycle, and aromatic polyisocyanates.

[0113] Aliphatic polyisocyanates include, for example, hexamethylene diisocyanate, tetramethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate.

[0114] Examples of alicyclic polyisocyanates include hydrogenated tolylene diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and isophorone diisocyanate trimer.

[0115] An example of the polyisocyanate having a heterocycle is hexamethylene diisocyanate trimer.

[0116] Examples of aromatic polyisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, paraphenylene diisocyanate, and 1,5-naphthalene diisocyanate.

[0117] {Hydroxyl group-containing (meth)acrylate} Examples of the hydroxyl group-containing (meth)acrylate include the compounds exemplified above in the section "(Compound having a hydroxyl group and an ethylenically unsaturated group)."

[0118] Furthermore, as the hydroxyl group-containing (meth)acrylate, a compound having a hydroxyl group and two or more (meth)acryloyl groups (hereinafter also referred to as "hydroxyl group-containing polyfunctional (meth)acrylate") may be used.

[0119] Examples of hydroxyl group-containing polyfunctional (meth)acrylates include glycerin di(meth)acrylate, isocyanuric acid alkylene oxide-modified di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di- or tri(meth)acrylate, ditrimethylolpropane di- or tri(meth)acrylate, and dipentaerythritol di-, tri-, tetra-, or penta(meth)acrylate. As used herein, alkylene oxide-modified includes, for example, ethylene oxide-modified, propylene oxide-modified, and ethylene oxide and propylene oxide-modified.

[0120] (Polyester (meth)acrylate) Examples of polyester (meth)acrylates include dehydration condensates of polyester diols and (meth)acrylic acid. Examples of polyester diols include reaction products of polyhydric alcohols (e.g., diols) and polycarboxylic acids (e.g., dicarboxylic acids) or their anhydrides.

[0121] {Diol} Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, butylene glycol, polybutylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol, as well as alkylene oxide adducts thereof.

[0122] {dicarboxylic acid} Examples of dicarboxylic acids or anhydrides thereof include orthophthalic acid, isophthalic acid, terephthalic acid, adipic acid, succinic acid, fumaric acid, maleic acid, hexahydrophthalic acid, tetrahydrophthalic acid, and trimellitic acid, and anhydrides thereof.

[0123] (Epoxy (meth)acrylate) Examples of epoxy (meth)acrylates include compounds obtained by addition reaction of epoxy resins with (meth)acrylic acid. Examples of epoxy resins include aromatic epoxy resins and aliphatic epoxy resins.

[0124] {Aromatic epoxy resin} Examples of aromatic epoxy resins include resorcinol diglycidyl ether, hydroquinone diglycidyl ether; diglycidyl ethers of bisphenol A, bisphenol F, bisphenol S, bisphenol fluorene, or alkylene oxide adducts thereof; novolac epoxy resins such as phenol novolac epoxy resins and cresol novolac epoxy resins; glycidyl phthalimide; and o-phthalic acid diglycidyl ester.

[0125] {Aliphatic epoxy resin} Examples of aliphatic epoxy resins include diglycidyl ethers of alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol; diglycidyl ethers of polyalkylene glycols such as diglycidyl ethers of polyethylene glycol and polypropylene glycol; diglycidyl ethers of neopentyl glycol, dibromoneopentyl glycol, and alkylene oxide adducts thereof; diglycidyl ethers of hydrogenated bisphenol A and alkylene oxide adducts thereof; and tetrahydrophthalic acid diglycidyl ester.

[0126] (Other compounds) Examples of other compounds having an ethylenically unsaturated group include the following compounds:

[0127] Alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate.

[0128] (meth)acrylates having an alicyclic group, such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, and 1-adamantyl (meth)acrylate.

[0129] Alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate and 2-ethoxyethoxyethyl (meth)acrylate.

[0130] (Meth)acrylates having a heterocycle, such as tetrahydrofurfuryl (meth)acrylate and glycerin carbonate (meth)acrylate.

[0131] (Meth)acrylates having an aromatic ring, such as phenyl (meth)acrylate, o-phenylphenyl (meth)acrylate, p-cumylphenyl (meth)acrylate, benzyl (meth)acrylate, (meth)acrylates of phenol alkylene oxide adducts, (meth)acrylates of p-cumylphenol alkylene oxide adducts, (meth)acrylates of o-phenylphenol alkylene oxide adducts, and (meth)acrylates of nonylphenol alkylene oxide adducts.

[0132] (Meth)acrylates such as glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and allyl (meth)acrylate.

[0133] Bifunctional (meth)acrylates having an aromatic skeleton, such as di(meth)acrylate of bisphenol A alkylene oxide adduct, bisphenol A di(meth)acrylate, and di(meth)acrylate of bisphenol F alkylene oxide adduct.

[0134] Bifunctional (meth)acrylates having an aliphatic skeleton, such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, polybutylene glycol di(meth)acrylate, poly(1-methylbutylene glycol) di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate.

[0135] Hydroxypivalic acid neopentyl glycol di(meth)acrylate, and hydroxypivalic acid neopentyl glycol ε-caprolactone-modified di(meth)acrylate.

[0136] Bifunctional (meth)acrylates having an alicyclic skeleton, such as dimethyloltricyclodecane di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and spiroglycol di(meth)acrylate.

[0137] 2-Ethylhexyl alkylene oxide-modified (meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane alkylene oxide-modified tri(meth)acrylate, isocyanuric acid alkylene oxide-modified tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, diglycerin alkylene oxide-modified (meth)acrylate, ω-carboxy-polycaprolactone mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate.

[0138] The active energy ray-curable monomer may be one type or multiple types.

[0139] The active energy ray-curable monomer is preferably hydrophobic, and more preferably water-insoluble or water-immiscible. The term "water-insoluble" means that when the active energy ray-curable monomer is solid, the amount that dissolves in 100 g of water at 25°C is 5 g or less. The term "water-immiscible" means that when the active energy ray-curable monomer is liquid, it does not mix with water at 25°C.

[0140] The amount of the water-insoluble active energy ray-curable monomer that dissolves in 100 g of water at 25° C. may be 4 g or less, 3 g or less, 2 g or less, 1 g or less, or 0.5 g or less.

[0141] [Photopolymerization initiator] The active energy ray-curable composition according to this embodiment may further contain a photopolymerization initiator. Note that, when the active energy ray-curable composition is cured with an electron beam, for example, the composition does not need to contain a photopolymerization initiator.

[0142] Examples of the photopolymerization initiator include the following compounds:

[0143] Benzyl dimethyl ketal, benzil, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone (IGM Resins BV, Omnirad184D), 2-hydroxy-2-methyl-1-phenylpropan-1-one (IGM Resins BV, Omnirad1173), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (IGM Resins BV, Omnirad2959), oligo[2-hydroxy-2-methyl-1-[4-1-(methylvinyl)phenyl]propanone, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl]-2-methylpropan-1-one (IGM Resins BV, Omnirad aromatic ketone compounds such as 2-methyl-1-[4-(methylthio)]phenyl]-2-morpholinopropan-1-one (IGM Resins BV, Omnirad127), 2-methyl-1-[4-(methylthio)]phenyl]-2-morpholinopropan-1-one (IGM Resins BV, Omnirad907), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one (IGM Resins BV, Omnirad369), and 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (IGM Resins BV, Omnirad379).

[0144] Benzophenone-based compounds such as benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, 4-(methylphenylthio)phenylphenylmethane, methyl-2-benzophenone, 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, and 4-methoxy-4'-dimethylaminobenzophenone.

[0145] Acylphosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-(2,4,6-trimethylbenzoyl)phenylphosphineate, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0146] Thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propylthioxanthone, 3-[3,4-dimethyl-9-oxo-9H-thioxanthone-2-yl]oxy]-2-hydroxypropyl-N,N,N-trimethylammonium chloride, and fluorothioxanthone.

[0147] Acridone and acridone compounds such as 10-butyl-2-chloroacridone.

[0148] Oxime esters such as 1,2-octanedione 1-[4-(phenylthio)-2-(O-benzoyloxime)], and ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime).

[0149] 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-phenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer.

[0150] acridine derivatives such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane;

[0151] Adeka Optoma-N-1414 (manufactured by ADEKA Corporation), phenylglyoxylic acid methyl ester, ethyl anthraquinone, and phenanthrenequinone.

[0152] The amount of the photopolymerization initiator is preferably 0.05 to 20.0 mass %, more preferably 0.3 to 15.0 mass %, and even more preferably 0.5 to 10.0 mass %, based on the mass of the active energy ray-curable monomer.

[0153] [Other ingredients] The active energy ray-curable composition according to this embodiment may contain, for example, a solvent, a dispersion medium, an antifoaming agent, a thickener, a pigment, a pH adjuster, a crosslinking agent, a plasticizer, a stabilizer, a preservative, an antioxidant, a light stabilizer, or an ultraviolet absorber.

[0154] <Method of manufacturing the cured product> One embodiment of the present invention relates to a method for producing a cured product, comprising the step of irradiating the above-described active energy ray-curable composition with active energy rays to cure the composition.

[0155] Examples of active energy rays include ultraviolet rays, visible light, and electron beams.

[0156] When ultraviolet light is selected as the active energy ray, an ultraviolet light irradiation device can be used. Examples of light sources in the ultraviolet light irradiation device include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a black light lamp, a UV electrodeless lamp, and an LED.

[0157] The conditions for irradiation with active energy rays may be adjusted as appropriate depending on, for example, the components of the active energy ray-curable composition or the application of the cured product.

[0158] <Cured product> One embodiment of the present invention relates to a cured product obtained by curing the above-described active energy ray-curable composition.

[0159] Examples of uses of the active energy ray-curable composition or a cured product thereof include molding resins that utilize polymerization or crosslinking reactions, casting resins, resins for stereolithography, sealants, dental polymerized resins, printing inks, printing varnishes, paints, photosensitive resins for printing plates, color proofs for printing, color filter resists, black matrix resists, photospacers for liquid crystal displays, rear projection screen materials, optical fibers, rib materials for plasma displays, dry film resists, resists for printed circuit boards, solder resists, photoresists for semiconductors, resists for microelectronics, resists for manufacturing micromachine parts, etching resists, microlens arrays, insulating materials, hologram materials, optical switches, waveguide materials, overcoating agents, powder coatings, adhesives, pressure-sensitive adhesives, release agents, optical recording media, pressure-sensitive adhesives, release coating agents, compositions for image recording materials using microcapsules, and various devices. [Example]

[0160] The present invention will be described in more detail below using examples and comparative examples, but the technical scope of the present invention is not limited to these.

[0161] Various values ​​in the examples may be used as preferred lower or upper limits in the embodiments of the present invention. Two values ​​of the same type in the examples may be appropriately combined to form a preferred numerical range.

[0162] <Measurement of various properties> [Carboxylic acid content of oxidized cellulose] To 100 mL of an aqueous cellulose dispersion, prepared in the following Production Example with an oxidized cellulose concentration adjusted to 0.1% by mass, was added 0.1 M aqueous hydrochloric acid to adjust the pH to 2.5, and then 0.05 N aqueous sodium hydroxide solution was added dropwise and the electrical conductivity was measured until the pH reached 11.0. The amount of carboxyl groups (mmol / g) was calculated using the following formula from the amount of sodium hydroxide (a) consumed in the neutralization stage of the weak acid, where the change in electrical conductivity was gradual. Amount of carboxyl group = a (mL) × 0.05 / mass of cellulose (g)

[0163] <Production of modified nanocellulose> [Production Example 1: Amine-modified nanocellulose] (oxidation process) A jacketed glass vessel was charged with 500 g of sodium hypochlorite solution with a pH of 12.7 and an available chlorine concentration of 12.5% ​​by mass, and the mixture was heated to 35°C while stirring at 200 rpm using a Shinto Scientific mixer (Three-One Motor, BL600) with three swept-back blades. Then, 47 g of powdered pulp (KC Flock W-100GK) from Nippon Paper Industries Co., Ltd. was added as a cellulosic raw material. After the cellulosic raw material was added, the mixture was stirred at 35°C until the pH dropped to 10.5. Then, a 25% by mass aqueous sodium hydroxide solution was added to maintain the pH at 10.5 during the reaction. The mixture was stirred under the same conditions for a total of 520 minutes after the cellulosic raw material was added.

[0164] After the reaction was completed, the remaining sodium hypochlorite was inactivated by adding aqueous hydrogen peroxide, and then hydrochloric acid was added to convert the carboxyl groups of the oxidized cellulose from the salt form (-COO-Na) to the proton form (-COO-H), yielding an aqueous dispersion with a pH of 2.5. The solid-liquid separation was carried out by pressure filtration at 0.2 MPa, and then the dispersion was washed with an aqueous hydrochloric acid solution at pH 2.5.

[0165] Sodium hydroxide was added to the resulting proton-type oxidized cellulose to convert the carboxylic acid groups from the proton type (-COO-H) back to the salt type (-COO-Na), yielding an aqueous dispersion of Na-type oxidized cellulose at pH 7.4.

[0166] The amount of carboxyl groups in the oxidized cellulose was measured and found to be 0.78 mmol / g. The nitrogen content derived from N-oxyl compounds in the oxidized cellulose was measured using a trace total nitrogen analyzer (TN-2100H, manufactured by Nitto Seiko Analytech Co., Ltd.), and the increase from the raw pulp was calculated, resulting in a value of less than 1 ppm.

[0167] (defibration process) An aqueous dispersion of Na-type oxidized cellulose (7.5% solids by mass) was processed in a homomixer (Primix, Robomix) at 10,000 rpm with 440 g of liquid for 33 minutes to defibrate the oxidized cellulose into nanocellulose, yielding an aqueous nanocellulose dispersion. The resulting aqueous dispersion was adjusted to a pH of 2.0-2.1 by adding 1N hydrochloric acid solution, and then washed twice with pure water using a tabletop multi-rack centrifuge (KOKUSAN, H-40α). The mixture was then washed (substituted) four times with acetone, followed by concentration by suction filtration using a vacuum pump to obtain acetone-substituted H-type nanocellulose.

[0168] (Denaturation process) To the H-type nanocellulose, an amount of JEFFAMINE M-2005 (weight average molecular weight: 2,000, manufactured by Tomoe Engineering Co., Ltd.) equivalent to the acid value was added and stirred. Toluene was added to this, and the solids concentration was adjusted to 5% by mass. The residue was removed by filtration using a filter cloth, and the acetone was distilled off using an evaporator to obtain amine-modified nanocellulose.

[0169] <Production of active energy ray-curable composition and cured product thereof> [Example 1] The acetone dispersion of the amine-modified nanocellulose produced in Production Example 1 (solid content 1.0% by mass) and Aronix M-113 (manufactured by Toagosei Co., Ltd.) were mixed and stirred for 10 minutes or more. The solvent was removed using an evaporator, and the amount of solvent was reduced to 8% by mass or less. 3 parts by mass of a photopolymerization initiator (Omnirad 184, manufactured by IBM Resins BV) was added to 100 parts by mass of this mixture to produce an active energy ray-curable composition. The resulting composition was poured into a 1 mm thick mold sandwiched between PET films. Using a conveyor-type ultraviolet irradiation device (US5-X0602 manufactured by Eye Graphics Co., Ltd.), the composition was irradiated at an integrated irradiance of 5000 mW / cm. 2 The composition was cured by UV irradiation so that the temperature became 100°C, and a sheet-like cured product was obtained. The amount of modified nanocellulose in this example (not the dispersion, but the modified nanocellulose itself) was 2% by mass based on the mass of M-113.

[0170] [Example 2] A cured product was obtained in the same manner as in Example 1, except that the amount of amine-modified nanocellulose in Example 1 was changed from 2% by mass to 1% by mass.

[0171] [Comparative Example 1] A cured product was obtained in the same manner as in Example 1, except that the amine-modified nanocellulose in Example 1 was not used. The composition of Comparative Example 1 corresponds to the target composition for Examples 1 and 2, and the cured product of Comparative Example 1 corresponds to the target cured product. The breaking elongation ratio, maximum stress ratio, elastic modulus ratio, and breaking work ratio in Table 1 were calculated from the ratios of the breaking elongation, maximum stress, elastic modulus, and breaking work of the Examples to the breaking elongation, maximum stress, elastic modulus, and breaking work of the Examples, respectively, relative to the breaking elongation, maximum stress, elastic modulus, and breaking work of the Examples in Comparative Example 1.

[0172] Comparative Example 2 An active energy ray-curable composition was produced in the same manner as in Example 1, except that the amine-modified nanocellulose in Example 1 was replaced with the unmodified nanocellulose produced in Production Example 1 (obtained in the [defibration step]). Unmodified nanocellulose did not disperse in Aronix M-113, so the cured product was not evaluated as described below.

[0173] <Evaluation of the cured product> From the sheet-like cured products obtained in the above Examples and Comparative Examples, rectangular test pieces (thickness: approximately 1 mm) with a total length of 50 mm and a gauge width of 5 mm were cut out. These test pieces were subjected to a tensile test in accordance with JIS K6251 using a tensile tester (INSTRON, INSTRON 5566A) at 23±2°C, a gauge length of 10 mm, and a tensile speed of 100 mm / min. The breaking elongation (%), maximum stress (kPa), modulus of elasticity (kPa), and work at fracture (mJ) were measured by tensile testing. The results are shown in Table 1 and Figure 1.

[0174] [Table 1]

Claims

1. Modified nanocellulose; an active energy ray-curable monomer; An active energy ray-curable composition comprising: The modified nanocellulose Nanocellulose and A modifying group introduced into the nanocellulose; Including, The modifying group is introduced into at least some of the carboxy groups of the nanocellulose via ionic bonds; the modifying group has an amino group; Active energy ray-curable composition.

2. The nanocellulose comprises an oxide of a cellulosic raw material with hypochlorous acid or a salt thereof, and is substantially free of N-oxyl compounds; The active energy ray-curable composition according to claim 1 .

3. The ratio of the breaking elongation of the cured product obtained by curing the active energy ray-curable composition to the breaking elongation of a control cured product obtained by curing a control composition in which the modified nanocellulose is removed from the active energy ray-curable composition is 0.6 or more. The active energy ray-curable composition according to claim 1 .

4. The ratio of the maximum stress value of the cured product obtained by curing the active energy ray-curable composition to the maximum stress value of a control cured product obtained by curing a control composition in which the modified nanocellulose is omitted from the active energy ray-curable composition is 1.10 or more. The active energy ray-curable composition according to claim 1 .

5. The ratio of the elastic modulus value of the cured product obtained by curing the active energy ray-curable composition to the elastic modulus value of a control cured product obtained by curing a control composition in which the modified nanocellulose is removed from the active energy ray-curable composition is 1.00 or more. The active energy ray-curable composition according to claim 1 .

6. The ratio of the work of fracture of a cured product obtained by curing the active energy ray-curable composition to the work of fracture of a control cured product obtained by curing a control composition in which the modified nanocellulose is removed from the active energy ray-curable composition is 1.2 or more. The active energy ray-curable composition according to claim 1 .

7. The modifying group is derived from a polyetheramine. The active energy ray-curable composition according to claim 1 .

8. The average fiber width of the modified nanocellulose is 1 to 50 nm; The active energy ray-curable composition according to claim 1 .

9. The average fiber length of the modified nanocellulose is 50 to 3000 nm. The active energy ray-curable composition according to claim 1 .

10. Further comprising a photopolymerization initiator, The active energy ray-curable composition according to claim 1 .

11. A cured product of the active energy ray-curable composition according to any one of claims 1 to 10.

12. A step of irradiating the active energy ray-curable composition according to any one of claims 1 to 10 with active energy rays to cure the composition; Including, Method for producing a cured product.

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