Production method for composition containing modified cellulose fibers and polymerizable compound

Abstract

The present invention provides a method for producing a composition containing modified cellulose fibers and a polymerizable compound, with which, even when said composition is stored, it is possible to suppress a change in viscosity of the composition after storage. This production method is characterized by including a step for mixing the following components (A) and (B), and in that modified cellulose fibers are obtained by ion-bonding the following components (A) and (B), and when the composition is stored, a change in viscosity of the composition after storage is suppressed. Component (A): anion-modified cellulose fibers. Component (B): one or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds.

Description

Method for producing a composition containing modified cellulose fibers and a polymerizable compound

[0001] The present invention relates to a method for producing a composition containing modified cellulose fibers and a polymerizable compound.

[0002] In recent years, attention has been drawn to the fact that adding microfibrillated cellulose fibers to materials such as resins significantly improves various mechanical properties of the materials. For example, Patent Document 1 discloses an example of a non-aqueous coating composition containing an epoxy resin and a microfibrillated cellulose fiber composite. By hydrophobizing the microfibrillated cellulose fibers, they can be nano-dispersed in the resin. Therefore, adding such hydrophobically modified microfibrillated cellulose fibers to transparent resin materials such as acrylic resins is expected to improve mechanical properties while maintaining transparency.

[0003] JP 2019-119881 A

[0004] When the present inventors mixed hydrophobically modified cellulose fibers with polymerizable compounds such as acrylic monomers and stored the resulting mixture, they found that the viscosity of the resulting mixture sometimes changed so significantly that it was not possible to proceed to the next step.

[0005] Therefore, the present invention relates to providing a method for producing a composition containing modified cellulose fibers and a polymerizable compound, which can suppress changes in viscosity of the composition after storage, even when the composition is stored.

[0006] That is, the present invention relates to the following items [1] to

[26] . [1] A method for producing a composition containing a modified cellulose fiber and a polymerizable compound, comprising a step of mixing the following component (A) and component (B), wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and component (B), and wherein when the composition is stored, a change in viscosity of the composition after storage is suppressed. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds.

[0007] [2] A method for producing the composition according to [1] above, further comprising, after the step of mixing component (A) and component (B), a step of mixing the obtained modified cellulose fiber with a polymerizable compound. [3] A method for producing the composition according to [2] above, further comprising, before the step of mixing the modified cellulose fiber with the polymerizable compound, a step of micronizing the modified cellulose fiber. [4] A method for producing the composition according to any one of [1] to [3] above, wherein the blending ratio of component (A) to component (B) is 1 part by mass or more and 5,000 parts by mass of component (B) per 100 parts by mass of component (A). [5] A method for producing the composition according to any one of [1] to [4] above, wherein the amount of polymerizable compound added is 10 parts by mass or more and 100,000 parts by mass or less per 100 parts by mass of component (A). [6] A method for producing the composition according to any one of [1] to [5], wherein the amount of the modified cellulose fiber added is 0.1 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the polymerizable compound. [7] A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B), and the composition has a relative viscosity of 50 or more and 200 or less after storage at 40°C for 72 hours. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds. [8] The composition according to [7], wherein the modified cellulose fiber is obtained by adding 1 part by mass or more and 5,000 parts by mass or less of component (B) per 100 parts by mass of component (A). [9] The composition according to [7] or [8] above, wherein the content of the polymerizable compound in the composition is 10 parts by mass or more and 100,000 parts by mass or less per 100 parts by mass of component (A).

[10] The composition according to any one of [7] to [9] above, wherein the content of the modified cellulose fiber in the composition is 0.1 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the polymerizable compound.

[11] The composition according to any one of [7] to

[10] above, wherein the content of the modified cellulose fiber in the composition is 0.1% by mass or more and 50% by mass or less.

[12] The composition according to any one of [7] to

[11] above, wherein the molecular weight of component (B) is 50 or more and 50,000 or less.

[13] A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B), and wherein the composition has a relative viscosity of 50 or more and 200 or less after storage at 40°C for 72 hours. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds

[14] A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds

[15] The composition according to

[14] above, wherein the modified cellulose fiber is obtained by adding 1 part by mass or more and 5,000 parts by mass or less of component (B) to 100 parts by mass of component (A).

[16] The composition according to

[14] or

[15] above, wherein the content of the polymerizable compound in the composition is 10 parts by mass or more and 100,000 parts by mass or less to 100 parts by mass of component (A).

[17] The composition according to any one of

[14] to

[16] above, wherein the content of the modified cellulose fiber in the composition is 0.1% by mass or more and 50% by mass or less.

[18] The composition according to any one of

[14] to

[17] above, wherein component (B) is a polyether-type tertiary amine represented by the following formula (A2):

[0008]

[0009] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each value being 1 to 100, and the sum of n and m (n + m) is 2 or more and 200 or less.)

[19] A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds

[20] A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B). Component (A): Anion-modified cellulose fiber Component (B): Polyether-type tertiary amine represented by the following formula (A2)

[0010]

[0011] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each value being 1 to 100, and the sum of n and m (n + m) is more than 20 and less than 80.)

[21] A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Polyether-type tertiary amine represented by the following formula (A2):

[0012]

[0013] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, and n and m are each the average number of moles of AO added, each value being 1 to 100, and the sum of n and m (n + m) is more than 20 and less than 80.)

[22] A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and component (B): Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine

[23] A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and component (B): Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine

[24] A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less: Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds

[25] A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Polyether-type tertiary amine represented by the following formula (A2):

[0014]

[0015] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each value being 1 to 100, and the sum of n and m (n + m) is more than 20 and less than 80.)

[26] A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 130 or more. Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine Detailed Description of the Invention

[0016] According to the present invention, it is possible to provide a method for producing a composition containing modified cellulose fiber and a polymerizable compound, which can suppress changes in viscosity of the composition after storage, even when the composition is stored.

[0017] [Method for producing a composition containing a modified cellulose fiber and a polymerizable compound] The method for producing a composition containing a modified cellulose fiber and a polymerizable compound of the present invention comprises a step of mixing the following component (A) and component (B), wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and component (B), and wherein when the composition is stored, a change in viscosity of the composition after storage is suppressed. Component (A): Anion-modified cellulose fiber. Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds.

[0018] The present inventors have investigated various amines as components for modifying anion-modified cellulose fibers in order to suppress changes in viscosity of the composition after storage. As a result, they have unexpectedly found that the viscosity change can be suppressed by using a compound having a specific structure, referred to herein as component (B), i.e., one or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds, and have completed the present invention.

[0019] Although the mechanism by which the viscosity change of the composition can be suppressed is not clear, it is presumed that the viscosity change of the composition occurs due to a Michael addition reaction occurring between one or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds and a polymerizable compound, particularly between a compound having an α,β-unsaturated carbonyl group such as an acrylic monomer, and that the viscosity change of the composition can be suppressed by suppressing such a Michael addition reaction.

[0020] Here, the Michael addition reaction is a reaction in which a nucleophile is added to a compound having an α,β-unsaturated carbonyl group, and the acrylic monomer corresponds to the compound having an α,β-unsaturated carbonyl group, and the primary amine or secondary amine corresponds to the nucleophile.

[0021] As shown in Scheme 1 below, primary amines readily undergo a Michael addition reaction with acrylic monomers, which are compounds having an α,β-unsaturated carbonyl group, to produce tertiary amines. Similarly, secondary amines produce tertiary amines.

[0022]

[0023] The tertiary amine thus produced is thought to have a lower ability to bond to anion-modified cellulose fibers than the original primary amine due to its steric hindrance.

[0024] Therefore, when an attempt is made to modify anion-modified cellulose fibers with a primary amine or a secondary amine in the presence of a compound having an α,β-unsaturated carbonyl group, a less reactive tertiary amine is produced, which inhibits the modification of the anion-modified cellulose fibers. As a result, the anion-modified cellulose fibers are not hydrophobized and aggregate over time, which is thought to cause a change in the viscosity of the composition.

[0025] In contrast, when a tertiary amine or quaternary ammonium compound was used as the modifying compound, the viscosity of the composition showed little change over time. This is thought to be because the Michael addition reaction was inhibited or prevented when a tertiary amine or quaternary ammonium compound was used, and these compounds were used to modify the anion-modified cellulose fiber without being used up.

[0026] In the present invention, the "change in viscosity of a composition after storage" refers to the change in viscosity of a composition after storage when the composition to be evaluated is stored, for example, for one day to six months, under conditions of 25 to 80°C. Specifically, if the relative viscosity (relative to the viscosity immediately after preparation of the composition, which is set to 100) after 72 hours of storage at 40°C, as determined by the "evaluation of viscosity change" described in the Examples, is 50 to 200, the composition is judged to have suppressed viscosity change. Furthermore, if the relative viscosity after 24 hours of storage at 80°C, as determined by the "evaluation of viscosity change" described in the Examples, is 50 to 200, the composition is judged to have suppressed viscosity change at high temperatures. Therefore, a composition that has a relative viscosity of 50 to 200 after 72 hours of storage at 40°C and a relative viscosity of 50 to 200 after 24 hours of storage at 80°C is judged to have further suppressed viscosity change. It can be said that the closer the relative viscosity is to 100, the more the viscosity change is suppressed, and when the relative viscosity is 100, it can be said that no viscosity change occurs.

[0027] According to the method for producing a composition of the present invention, by mixing a polymerizable compound with modified cellulose fiber obtained by mixing components (A) and (B), it is possible to suppress changes in the viscosity of the mixture containing the modified cellulose fiber and the polymerizable compound after storage. The relative viscosity of the mixture containing the modified cellulose fiber and the polymerizable compound after storage at 40°C for 72 hours is preferably 50 or more, more preferably 80 or more, and even more preferably 90 or more, from the viewpoint of achieving the intended function of the composition, such as applying the intended composition to form a coating film or dispersing insoluble matter such as pigments in the composition. On the other hand, the relative viscosity after storage at 40°C for 72 hours is preferably 200 or less, more preferably 130 or less, and even more preferably 110 or less, from the viewpoint of easy handling of the mixture.

[0028] The method for producing the composition of the present invention includes a step of mixing anion-modified cellulose fibers with one or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds having specific structures. By mixing these compounds, it is possible to suppress viscosity changes after storage of the resulting mixture containing modified cellulose fibers having specific structures and a polymerizable compound, and it is also possible to prepare the composition of the present invention. This mixing step forms ionic bonds between the anion-modified cellulose fibers and one or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds.

[0029] [Step of Mixing Component (A) and Component (B)] In the step of mixing component (A) and component (B), specifically, component (A) and component (B) are mixed in a solvent. As the solvent, a polymerizable compound may be used, an organic solvent other than the polymerizable compound may be used, or both may be used in combination. Furthermore, water may be present during mixing.

[0030] When a polymerizable compound is used as the solvent, a composition containing the modified cellulose fiber and the polymerizable compound can be produced by the step of mixing component (A) and component (B).

[0031] Details of the "step of mixing component (A) and component (B)" are described in (Step 2) of [Method for producing modified cellulose fiber].

[0032] [Step of mixing modified cellulose fiber and polymerizable compound] When an organic solvent other than the polymerizable compound is used as the solvent, a dispersion containing the modified cellulose fiber and the organic solvent other than the polymerizable compound can be obtained by mixing component (A) and component (B). The organic solvent may or may not be separated from the resulting dispersion, but the modified cellulose fiber can be isolated by separation.

[0033] The production method of the present invention may further include a step of mixing the obtained modified cellulose fiber with a polymerizable compound after the above-mentioned "step of mixing component (A) and component (B)." This step allows for the production of a composition containing the modified cellulose fiber and the polymerizable compound. Note that the "obtained modified cellulose fiber" may be an "isolated modified cellulose fiber," or a "dispersion containing the modified cellulose fiber and an organic solvent other than the polymerizable compound."

[0034] The amount of modified cellulose fiber added in this process is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the polymerizable compound, from the viewpoint of various mechanical properties of the material; and from the viewpoint of ease of resin production, it is preferably 100 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the polymerizable compound.

[0035] The amount of polymerizable compound added in this step is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, and even more preferably 1,000 parts by mass or more, per 100 parts by mass of component (A) from the viewpoint of ease of resin production, and is preferably 100,000 parts by mass or less, more preferably 50,000 parts by mass or less, even more preferably 20,000 parts by mass or less, and even more preferably 10,000 parts by mass or less, per 100 parts by mass of component (A), from the viewpoint of various mechanical properties of the material.

[0036] [Modified Cellulose Fiber] The modified cellulose fiber of the present invention is a cellulose fiber having a structure formed by ionic bonding of component (A) and component (B). Component (A): Anion-modified cellulose fiber. Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds. By bonding component (B) or the like to the cellulose fiber, the cellulose fiber can be made hydrophobic, thereby weakening the hydrogen bonds between the cellulose fibers. Therefore, such modified cellulose fiber has higher dispersibility in various media such as resins and organic solvents than unmodified cellulose fiber.

[0037] [Component (A)] Component (A) in the present invention is an anion-modified cellulose fiber. Anion-modified cellulose fibers are cellulose fibers having an anionic group, such as one or more groups selected from the group consisting of a carboxy group, a (phosphorous) group, and a sulfonic acid group, in the molecule. From the standpoint of availability and effectiveness, anion-modified cellulose fibers having a carboxy group as the anionic group (referred to as "oxidized cellulose fibers") are preferred, and anion-modified cellulose fibers in which the hydroxymethyl group at the C6 position of the glucose unit constituting the cellulose fiber is selectively converted to a carboxy group (referred to as "TEMPO-oxidized cellulose fibers") are more preferred. The counter ion of the anionic group is preferably a proton, sodium ion, potassium ion, or the like, more preferably a proton. The introduction of anionic groups into cellulose fibers can be achieved, for example, by the methods described herein.

[0038] The anionic group content in component (A) is preferably 0.1 mmol / g or more, more preferably 0.4 mmol / g or more, even more preferably 0.6 mmol / g or more, even more preferably 0.7 mmol / g or more, and even more preferably 0.8 mmol / g or more, from the viewpoint of introducing a stable component (B) and improving the dispersibility of the microfibrillated modified cellulose fiber by introducing component (B). Furthermore, from the viewpoint of improving handleability, it is preferably 3 mmol / g or less, more preferably 2.5 mmol / g or less, even more preferably 2 mmol / g or less, and even more preferably 1.9 mmol / g or less. The term "anionic group content" refers to the total amount of anionic groups in the glucose constituting the cellulose fiber, and is specifically measured by the method described in the Examples below.

[0039] [Component (B)] Component (B) in the present invention is one or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds. Component (B) is bonded to the anionic group of component (A) via an ionic bond. In this specification, tertiary amines include not only compounds in which three hydrogen atoms of ammonia are substituted with hydrocarbon groups, but also compounds in which three hydrogen atoms of ammonia are substituted with functional groups other than hydrocarbon groups, and quaternary ammonium compounds include not only compounds in which four hydrogen atoms of an ammonium ion are substituted with hydrocarbon groups, but also compounds in which four hydrogen atoms of an ammonium ion are substituted with functional groups other than hydrocarbon groups.

[0040] The molecular weight of component (B) is preferably 50 or more, more preferably 100 or more, even more preferably 130 or more, even more preferably 200 or more, even more preferably 500 or more, even more preferably 1000 or more, even more preferably 1400 or more, and even more preferably 1500 or more, from the viewpoint of dispersibility in various media such as resins and organic solvents, and is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less, from the viewpoint of various mechanical properties of the material.

[0041] When component (B) is a component having a molecular weight distribution, the weight average molecular weight of component (B) is preferably 50 or more, more preferably 1,000 or more, from the viewpoint of dispersibility in various media such as resins and organic solvents, and is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less, from the viewpoint of various mechanical properties of the material.

[0042] When component (B) is a component having a molecular weight distribution, the number average molecular weight of component (B) is preferably 50 or more, more preferably 1,000 or more, from the viewpoint of dispersibility in various media such as resins and organic solvents, and is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less, from the viewpoint of various mechanical properties of the material.

[0043] Examples of component (B) include tertiary monoamines, tertiary polyamines, monoquaternary ammonium compounds, and polyquaternary ammonium compounds, and preferably tertiary monoamines or tertiary diamines. Examples of tertiary monoamines include tertiary amines represented by the following formula (A1): １ R ２ R ３ N (A1) [wherein, R １ , R ２ and R ３ are monovalent hydrocarbon groups or functional groups represented by the following formula (B1), and may be the same or different from each other: -(AO) ｐ —H(B1) (In the formula, AO represents a divalent alkyleneoxy group, and p represents the average number of moles of alkylene oxide added, which is a number from 1 to 100 (wherein the p AOs may be the same or different). Preferred AOs include an ethylene oxide group and a propylene oxide group.)

[0044] R in formula (A1) １ , R ２ and R ３ From the viewpoint of suppressing a change in viscosity of a composition containing a polymerizable compound, R is preferably a monovalent hydrocarbon group having 1 to 22 carbon atoms or a functional group represented by the formula (B1), and more preferably a monovalent linear or branched alkyl or alkenyl group having 1 to 22 carbon atoms or a functional group represented by the formula (B1). １ , R ２ and R ３ At least one of the groups is a monovalent hydrocarbon group.

[0045] Examples of the tertiary amine represented by formula (A1) include trihexylamine, trioctylamine, tridecylamine, tridodecylamine, dihexylmonomethylamine, dioctylmonomethylamine, didecylmonomethylamine, didodecylmonomethylamine, dimethyloctylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethyloctadecylamine, dimethyloleylamine, dimethylbehenylamine, dimethylcoconutamine, and polyether-type tertiary amines represented by the following formula (A2).

[0046]

[0047] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each number being 1 to 100, and the sum of n and m (n+m) is 2 or more and 200 or less. Preferred R includes an alkyl group having 10 to 20 carbon atoms. Preferred AO includes one or two types selected from an ethylene oxide group and a propylene oxide group. n+m is preferably 10 or more, more preferably 20 or more, even more preferably more than 20, and is preferably 100 or less, more preferably less than 80, and even more preferably 50 or less.)

[0048] Preferred polyether-type tertiary amines include polyoxyethylene octylamine, polyoxyethylene laurylamine, polyoxyethylene stearylamine, and polyoxyethylene oleylamine.

[0049] Examples of the tertiary diamine include tertiary diamines represented by the following formula (A3): ４ R ５ N-M-NR ６ R ７ (A3) [In the formula, R ４ , R ５ , R ６ and R ７are monovalent hydrocarbon groups or functional groups represented by the formula (B1) above, and may be the same or different from each other. M is an alkylene group having 1 to 10 carbon atoms.

[0050] R in formula (A3) ４ , R ５ , R ６ and R ７ From the viewpoint of suppressing a change in viscosity of a composition containing the polymerizable compound, the aryl group is preferably a monovalent hydrocarbon group having from 1 to 22 carbon atoms or a functional group represented by the formula (B1), and more preferably a monovalent linear or branched alkyl or alkenyl group having from 1 to 22 carbon atoms, or a functional group represented by the formula (B1).

[0051] Examples of the tertiary diamine represented by formula (A3) include one or more selected from the group consisting of polyoxyethylene stearyl propylene diamine, polyoxyethylene lauryl propylene diamine, polyoxyethylene coconut propylene diamine, polyoxyethylene beef tallow propylene diamine, and polyoxyethylene-polyoxypropylene block polymers of ethylene diamine.

[0052] Tertiary polyamines include polymeric compounds having dialkylamino groups in the side chains, such as polymers of 2-(dimethylamino)ethyl methacrylate.

[0053] Examples of monoquaternary ammonium compounds include quaternary ammonium compounds represented by the following formula (A4): ８ R ９ R １０ R １１ N ＋ X － (A4) [In the formula, R ８ , R ９ , R １０ and R １１ are monovalent hydrocarbon groups or functional groups represented by the formula (B1), and may be the same or different. － is one or more ions selected from hydroxide ions and halide ions.

[0054] R ８ , R９ , R １０ and R １１ From the viewpoint of suppressing a change in viscosity of a composition containing a polymerizable compound, R is preferably a monovalent hydrocarbon group having 1 to 22 carbon atoms or a functional group represented by the formula (B1), more preferably a monovalent linear or branched alkyl or alkenyl group having 1 to 22 carbon atoms or a functional group represented by the formula (B1), and even more preferably a monovalent linear or branched alkyl or alkenyl group having 1 to 5 carbon atoms or a functional group represented by the formula (B1). ８ , R ９ , R １０ and R １１ At least one of the groups is a monovalent hydrocarbon group.

[0055] Suitable monoquaternary ammonium chlorides for component (B) include tetrabutylammonium chloride, tetrahexylammonium chloride, tetraoctylammonium chloride, tetradecylammonium chloride, dioctyldimethylammonium chloride, dilauryldimethylammonium chloride, dicetyldimethylammonium chloride, dipalmityldimethylammonium chloride, distearyldimethylammonium chloride, dioleyldimethylammonium chloride, lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, palmityltrimethylammonium chloride, stearyltrimethylammonium chloride, oleyltrimethylammonium chloride, and behenyltrimethylammonium chloride. , tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, tetradecylammonium hydroxide, dioctyldimethylammonium hydroxide, dilauryldimethylammonium hydroxide, dicetyldimethylammonium hydroxide, dipalmityldimethylammonium hydroxide, distearyldimethylammonium hydroxide, dioleyldimethylammonium hydroxide, lauryltrimethylammonium hydroxide, cetyltrimethylammonium hydroxide, palmityltrimethylammonium hydroxide, stearyltrimethylammonium hydroxide, oleyltrimethylammonium hydroxide, behenyltrimethylammonium hydroxide, and the like.

[0056] Examples of polyquaternary ammonium compounds suitable as component (B) include polymers of methyl chloride quaternary salt of dimethylaminoethyl acrylate, polymers of benzyl chloride quaternary salt of dimethylaminoethyl acrylate, polymers of dimethyldiallylammonium chloride, and polymers of cationized cellulose in which ammonium groups have been introduced into cellulose with glycidyltrimethylammonium chloride, (3-chloro-2-hydroxypropyl)trimethylammonium chloride, or the like, and polymers having trialkyl quaternary ammonium groups in the side chain.

[0057] As component (B), a tertiary amine and a quaternary ammonium compound may be used alone or in combination. When used in combination, the molar ratio of the quaternary ammonium compound to the tertiary amine ([quaternary ammonium compound] / [tertiary amine]) is preferably 1 / 100 or more, more preferably 1 / 50 or more, even more preferably 1 / 10 or more, and is preferably 100 / 1 or less, more preferably 50 / 1 or less, even more preferably 10 / 1 or less.

[0058] In the modified cellulose fiber of the present invention, amines other than component (B) (e.g., primary amines, secondary amines, etc.) may be present, but from the viewpoint of suppressing viscosity changes in the composition containing the polymerizable compound, it is preferable that the amount of such amines is small, and it is even more preferable that such amines are not present.

[0059] Component (B) may further have a substituent. Examples of the substituent include alkoxy groups having 1 to 6 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, and hexyloxy; methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, and tert-butoxycarbonyl; Examples thereof include alkoxycarbonyl groups having from 1 to 6 carbon atoms in the alkoxy group, such as a t-butoxycarbonyl group, a pentyloxycarbonyl group, and an isopentyloxycarbonyl group; halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; acyl groups having from 1 to 6 carbon atoms, such as an acetyl group and a propionyl group; aralkyl groups; aralkyloxy groups; alkylamino groups having from 1 to 6 carbon atoms; dialkylamino groups having from 1 to 6 carbon atoms in the alkyl group; and a hydroxy group.

[0060] [Modified Cellulose Fiber] The modified cellulose fiber preferably has a cellulose type I crystal structure from the viewpoint of improving dispersibility. The crystallinity of the modified cellulose fiber is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more from the viewpoint of improving dispersibility. Furthermore, from the viewpoint of raw material availability, it is preferably 90% or less, more preferably 85% or less, even more preferably 80% or less, and even more preferably 75% or less. In this specification, the crystallinity of various cellulose fibers refers to the cellulose type I crystallinity calculated from the diffraction intensity value by X-ray diffraction, and can be measured according to the method described in the Examples below. Cellulose type I refers to the crystalline form of native cellulose, and cellulose type I crystallinity refers to the proportion of crystalline regions in the entire cellulose fiber. The presence or absence of a cellulose type I crystal structure can be determined by the presence of a peak at 2θ = 22.6° in X-ray diffraction measurement.

[0061] From the viewpoint of improving dispersibility, the amount of component (B) bound in the modified cellulose fiber is preferably 0.01 mmol / g or more, more preferably 0.1 mmol / g or more, and even more preferably 0.5 mmol / g or more, and from the same viewpoint, it is preferably 3 mmol / g or less, more preferably 2 mmol / g or less, and even more preferably 1 mmol / g or less. When two or more compounds are simultaneously introduced as component (B) into the modified cellulose fiber, it is preferable that the total amount of component (B) bound is within the above range.

[0062] The introduction rate of component (B) in the modified cellulose fiber is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more from the viewpoint of improving dispersibility, and from the same viewpoint, it is preferably 100 mol% or less, more preferably 50 mol% or less, and even more preferably 40 mol% or less. When two or more compounds are simultaneously introduced as component (B), it is preferable that the total introduction rate be within the above range as long as it does not exceed the upper limit of 100 mol%.

[0063] The bonded amount and introduction rate of component (B) can be adjusted by the type and amount of component (B), reaction temperature, reaction time, type of solvent, etc. The bonded amount (mmol / g) and introduction rate (mol%) of component (B) refer to the amount and rate of component (B) introduced (bonded) to anionic groups in the refined modified cellulose fiber. For example, when the anionic group is a carboxy group, the bonded amount and introduction rate of component (B) in the modified cellulose fiber are calculated by the method described in the examples below.

[0064] From the viewpoint of improving the dispersibility of the modified cellulose fiber, the content of glucose moieties in the composition is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. On the other hand, from the viewpoint of handling during production, the content of glucose moieties in the composition is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably 2% by mass or less.

[0065] In this specification, the term "glucose portion" refers to the portion consisting of glucose units in various cellulose fibers, and in the case of unmodified cellulose fibers, it refers to the entire glucose unit, in the case of anion-modified cellulose fibers, it refers to the entire glucose unit including the anionic group bonded to the glucose unit, and in the case of modified cellulose fibers, it refers to the entire glucose unit excluding component (B) bonded to the glucose unit. That is, the glucose unit in this specification also includes glucose units in which the hydroxymethyl group has been converted to a carboxy group.

[0066] The average fiber diameter of the modified cellulose fiber is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 15 μm or more from the viewpoint of improving dispersibility when made into finely divided modified cellulose fiber. From the same viewpoint, it is preferably 300 μm or less, more preferably 100 μm or less, and even more preferably 60 μm or less. The average fiber length of the modified cellulose fiber is preferably 700 μm or more, more preferably 1000 μm or more, more preferably 1200 μm or more, and even more preferably 1500 μm or more from the viewpoint of improving dispersibility when made into finely divided modified cellulose fiber, availability, and economy. From the same viewpoint, it is preferably 10,000 μm or less, more preferably 5,000 μm or less, and even more preferably 3,000 μm or less. The average fiber diameter and average fiber length of the modified cellulose fiber can be measured according to the method described in the Examples below.

[0067] The modified cellulose fibers may be those that have been subjected to a micronization treatment to nanometer size. Such modified cellulose fibers are referred to as micronized modified cellulose fibers. The average fiber diameter of the micronized modified cellulose fibers is preferably 1 nm or more, more preferably 2 nm or more, and even more preferably 3 nm or more from the viewpoints of handleability, availability, and cost. From the viewpoints of improving handleability and dispersibility, it is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 100 nm or less, even more preferably 50 nm or less, and even more preferably 10 nm or less. The average fiber length of the micronized modified cellulose fibers is preferably 10 nm or more, more preferably 30 nm or more, even more preferably 50 nm or more, from the viewpoint of improving the dispersibility of the micronized modified cellulose fibers. On the other hand, from the viewpoint of improving the dischargeability and dispersibility of the micronized modified cellulose fibers, it is preferably 1000 nm or less, more preferably 500 nm or less, even more preferably 300 nm or less, and even more preferably 200 nm or less. The average fiber diameter and average fiber length of the micronized modified cellulose fibers are determined by the method described in the Examples below.

[0068] The average aspect ratio of the modified cellulose fiber and the pulverized modified cellulose fiber is preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more from the viewpoint of improving the dispersibility of the pulverized modified cellulose fiber, while from the viewpoint of improving the dischargeability and dispersibility of the pulverized modified cellulose fiber, it is preferably 300 or less, more preferably 200 or less, even more preferably 100 or less, and even more preferably 60 or less. By setting the average aspect ratio within the above range, both improved mechanical properties of resins and good dispersibility can be achieved, which is preferable. The average aspect ratio of the modified cellulose fiber and the pulverized modified cellulose fiber can be determined by the method described in the examples below.

[0069] [Method for producing modified cellulose fiber] The modified cellulose fiber can be produced, for example, by introducing anionic groups into raw cellulose fiber to produce component (A) (step 1), and then mixing component (A) with component (B) (step 2).

[0070] (Step 1) Raw Cellulose Fibers As the raw cellulose fibers for component (A), natural cellulose is preferred from an environmental perspective, and examples thereof include wood pulp such as softwood pulp and hardwood pulp; cotton pulp such as cotton linter and cotton lint; non-wood pulp such as straw pulp and bagasse pulp; and bacterial cellulose, and these may be used alone or in combination of two or more.

[0071] The average fiber diameter of the raw cellulose fibers is not particularly limited, but from the viewpoints of handleability and cost, it is preferably 5 μm or more, more preferably 7 μm or more, and from the same viewpoints, it is preferably 500 μm or less, more preferably 300 μm or less. The average fiber diameter of the raw cellulose fibers can be determined by the method described in the Examples below.

[0072] The average fiber length of the raw cellulose fibers is not particularly limited, but from the viewpoints of availability and cost, it is preferably 5 μm or more, more preferably 25 μm or more, and from the same viewpoints, it is preferably 5000 μm or less, more preferably 3000 μm or less. The average fiber length of the raw cellulose fibers can be determined by the method described in the Examples below.

[0073] Method for Introducing Anionic Groups Examples of anionic groups include a carboxy group, a (phosphorous) group, a sulfonic acid group, etc. Methods for introducing a carboxy group as an anionic group into cellulose fibers include, for example, a method of converting a hydroxy group of the cellulose fiber into a carboxy group by oxidation, and a method of reacting the hydroxy group of the cellulose fiber with at least one selected from the group consisting of a compound having a carboxy group, an acid anhydride of a compound having a carboxy group, and derivatives thereof.

[0074] Examples of methods for oxidizing the hydroxy groups of cellulose fibers include those described in Japanese Patent Laid-Open No. 2015-143336 and Japanese Patent Laid-Open No. 2015-143337, which involve reacting raw cellulose fibers with an oxidizing agent such as sodium hypochlorite and a bromide such as sodium bromide using 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) as a catalyst. By oxidizing cellulose fibers using TEMPO as a catalyst, the hydroxymethyl group at the C6 position of the glucose in the cellulose fiber structural unit is selectively converted to a carboxy group, thereby producing TEMPO-oxidized cellulose fibers, as described below.

[0075] Methods for introducing (phosphorous) groups as anionic groups into cellulose fibers include a method of mixing a powder or aqueous solution of (phosphorous) acid or a (phosphorous) derivative with dry or wet cellulose fibers, a method of adding an aqueous solution of (phosphorous) acid or a (phosphorous) derivative to a dispersion of cellulose fibers, etc. When these methods are employed, dehydration treatment, heat treatment, etc. are generally carried out after mixing or adding a powder or aqueous solution of (phosphorous) acid or a (phosphorous) derivative.

[0076] An example of a method for introducing phosphate groups as anionic groups into cellulose fibers is the method described in Japanese Patent No. 7196051, in which raw cellulose fibers are impregnated with a mixed aqueous solution of ammonium dihydrogen phosphate and urea to convert hydroxy groups of the cellulose fibers into phosphoric acid esters. An example of a method for introducing sulfonic acid groups as anionic groups into cellulose fibers is a method in which sulfuric acid is added to cellulose fibers and the fibers are heated.

[0077] (Step 2) Introduction of component (B) into the anionic groups of component (A) is achieved by mixing component (B) and component (A) in the presence of one or more solvents selected from the group consisting of water, organic solvents other than polymerizable compounds, and polymerizable compounds. By mixing, an ionic bond is formed between the anionic groups of component (A) and component (B), thereby introducing component (B) into the anionic groups of component (A). The modified cellulose fiber of the present invention is preferably one obtained by step 2. For a method of introducing component (B), reference can be made to JP 2015-143336 A.

[0078] The compounding ratio of component (A) to component (B) when preparing the modified cellulose fiber is, from the viewpoint of dispersibility in various media such as resins and solvents, preferably 1 part by mass or more, more preferably 10 parts by mass or more, and even more preferably 50 parts by mass or more, of component (B) per 100 parts by mass of component (A); and, from the viewpoint of various mechanical properties of the material, preferably 5,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 500 parts by mass or less, and even more preferably 300 parts by mass or less, of component (B) per 100 parts by mass of component (A).

[0079] After completion of step 2, post-treatment may be carried out as appropriate to remove unreacted compounds, etc. Examples of post-treatment methods that can be used include filtration, centrifugation, dialysis, etc.

[0080] Water may be present as a medium in step 2 above and the like.

[0081] The organic solvent other than the polymerizable compound and the polymerizable compound are used as a medium in the above step 2 and the step of micronizing the modified cellulose fiber.

[0082] The amount of the medium in step 2, i.e., one or more liquids selected from the group consisting of the polymerizable compound, an organic solvent other than the polymerizable compound, and water, may be any amount that can disperse component (A).

[0083] The melting points of the organic solvents other than the polymerizable compound and the polymerizable compound are preferably below 0°C, more preferably -50°C or lower, and even more preferably -60°C or lower, from the viewpoint of enhancing the dispersibility of the refined modified cellulose fiber. On the other hand, from the same viewpoint, those with a melting point of -100°C or higher are preferred. The boiling points of the organic solvents other than the polymerizable compound and the polymerizable compound are preferably 150°C or lower, more preferably 100°C or lower, and even more preferably 90°C or lower, from the viewpoint of enhancing the dispersibility of the refined modified cellulose fiber. On the other hand, those with a boiling point of 70°C or higher are preferred, from the viewpoint of reducing the amount of organic solvent used.

[0084] Specific examples of the organic solvent other than the polymerizable compound include alcohols having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, such as methanol, ethanol, propanol, and 1-methoxy-2-propanol (PGME); ketones having 3 to 6 carbon atoms, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; formic acid esters of alkyl groups having 1 to 4 carbon atoms, such as methyl formate and ethyl formate; acetate esters of alkyl groups having 1 to 4 carbon atoms, such as methyl acetate and ethyl acetate; and alkyl groups having 1 to 4 carbon atoms, such as methyl propionate and ethyl propionate. Examples of suitable solvents include propionic acid esters having 1 to 4 carbon atoms; butyric acid esters of alkyl groups having 1 to 4 carbon atoms, such as methyl butyrate and ethyl butyrate; P-based glycol ethers, such as 2-methoxy-1-methylethyl acetate (PGMEA); saturated or unsaturated hydrocarbons having 1 to 6 carbon atoms; aromatic hydrocarbons, such as benzene and toluene; halogenated hydrocarbons, such as methylene chloride and chloroform; lower alkyl ethers having 2 to 5 carbon atoms; and polar solvents, such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide and dimethyl sulfoxide. These may be used alone or in combination of two or more.

[0085] (Micronization Treatment) By micronizing raw cellulose fibers, anion-modified cellulose fibers, or modified cellulose fibers, it is possible to reduce the micrometer-scale cellulose fibers to nanometer-scale. Reducing the average fiber diameter to nanometer size is preferred because it improves dispersibility.

[0086] In the present invention, from the viewpoint of improving dispersibility, it is preferable to carry out a step of micronizing the modified cellulose fiber before the step of mixing the modified cellulose fiber with the polymerizable compound.

[0087] For the micronization treatment, a known micronization treatment method can be used. For example, to obtain micronized modified cellulose fibers having an average fiber diameter of nanometer size, a treatment method using a grinder such as a mass colloider or a treatment method using a high-pressure homogenizer in a medium may be carried out.

[0088] The medium may be one or more selected from the group consisting of organic solvents and polymerizable compounds other than the polymerizable compounds described above. The amount of the medium used may be any amount that can disperse the modified cellulose fiber, and is preferably at least 1 time, more preferably at least 2 times, and preferably at most 500 times, more preferably at most 200 times the mass of the modified cellulose fiber.

[0089] As the apparatus used in the micronization treatment, in addition to a high-pressure homogenizer, known dispersers are also suitably used. For example, a disintegrator, a beater, a low-pressure homogenizer, a grinder, a mass colloider, a cutter mill, a ball mill, a jet mill, a single-screw extruder, a twin-screw extruder, an ultrasonic agitator, a household juicer mixer, etc. can be used. In addition, the solids concentration of the modified cellulose fiber in the micronization treatment is preferably 50 mass% or less.

[0090] (Fiber Shortening Treatment) In the present invention, various cellulose fibers, i.e., raw cellulose fibers, anion-modified cellulose fibers, modified cellulose fibers, and finely divided modified cellulose fibers, may be subjected to a fiber shortening treatment. By performing such a fiber shortening treatment, the dispersibility of the finely divided modified cellulose fibers can be improved. The fiber shortening treatment can be performed by subjecting the target cellulose fibers to one or more treatment methods selected from the group consisting of (i) alkali treatment, (ii) acid treatment, and (iii) heat treatment, ultraviolet treatment, electron beam treatment, mechanical treatment, and enzyme treatment.

[0091] <Composition containing modified cellulose fiber and polymerizable compound> The composition containing modified cellulose fiber and polymerizable compound of the present invention is a composition containing modified cellulose fiber formed by ionically bonding the above-mentioned components (A) and (B), and the above-mentioned polymerizable compound. Furthermore, the composition of the present invention formed by blending modified cellulose fiber and polymerizable compound is a composition containing modified cellulose fiber formed by ionically bonding the above-mentioned components (A) and (B), and the above-mentioned polymerizable compound. Such a composition can be produced by mixing the modified cellulose fiber and the polymerizable compound.

[0092] The viscosity of such a composition is preferably 1 mPa·s or more, more preferably 5 mPa·s or more, and even more preferably 10 mPa·s or more at 25°C from the viewpoint of achieving the intended function of the composition, such as applying the intended composition to form a coating film or dispersing insoluble matter such as pigments in the composition. On the other hand, the viscosity of such a composition is preferably 10,000 mPa·s or less, more preferably 1,000 mPa·s or less, and even more preferably 300 mPa·s or less at 25°C from the viewpoint of facilitating handling of the composition. The viscosity of such a composition can be measured, for example, by the method described in the Examples.

[0093] The relative viscosity of the composition after storage at 40°C for 72 hours is preferably 50 or more, more preferably 80 or more, and even more preferably 90 or more, from the viewpoint of achieving the intended function of the composition, such as applying the composition to form a coating film and dispersing insoluble matters such as pigments in the composition. On the other hand, the relative viscosity of the composition after storage at 40°C for 72 hours is preferably 200 or less, more preferably 130 or less, and even more preferably 110 or less, from the viewpoint of facilitating handling of the composition.

[0094] The relative viscosity of the composition after storage at 80°C for 24 hours is preferably 10 or more, more preferably 50 or more, and even more preferably 70 or more, from the viewpoint of achieving the intended function of the composition, such as applying the composition to form a coating film and dispersing insoluble matters such as pigments in the composition. On the other hand, the relative viscosity of the composition after storage at 80°C for 24 hours is preferably 1000 or less, more preferably 500 or less, and even more preferably 300 or less, from the viewpoint of facilitating handling of the composition.

[0095] [Modified Cellulose Fiber] The modified cellulose fiber may be, for example, one obtained by the method described in the above-mentioned method for producing modified cellulose fiber.

[0096] The content of modified cellulose fiber in the composition of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 2% by mass or more, from the viewpoint of various mechanical properties of the material, and is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 9% by mass or less, from the viewpoint of handleability.

[0097] In addition, the preferred range of the content of modified cellulose fiber per 100 parts by mass of polymerizable compound in the composition of the present invention is the same range as the amount of modified cellulose fiber added in the process of mixing the polymerizable compound with the modified cellulose fiber or a dispersion containing the modified cellulose fiber and an organic solvent other than the polymerizable compound.

[0098] In the composition of the present invention, the modified cellulose fiber is formed by ionic bonding between the above-mentioned components (A) and (B). Here, the molecular weight of component (B) is preferably 500 or more, more preferably 1000 or more, even more preferably 1400 or more, and even more preferably 1500 or more, from the viewpoint of dispersibility in various media such as resins and organic solvents, and is preferably 50000 or less, more preferably 20000 or less, even more preferably 10000 or less, even more preferably 5000 or less, and even more preferably 2000 or less, from the viewpoint of various mechanical properties of the material.

[0099] In the composition of the present invention, the modified cellulose fiber is formed by ionic bonding between the above-mentioned components (A) and (B), where component (B) is preferably a polyether-type tertiary amine represented by the following formula (A2) or the above-mentioned tertiary diamine:

[0100]

[0101] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are the average number of moles of AO added, each number is 1 to 100, and the sum of n and m (n+m) is more than 20 and less than 80. Preferred R is an alkyl group having 10 to 20 carbon atoms. Preferred AO is one or both selected from an ethylene oxide group and a propylene oxide group. n+m is preferably more than 20 and 50 or less.)

[0102] [Polymerizable Compound] Examples of the polymerizable compound include compounds having an α,β-unsaturated carbonyl group, such as (meth)acrylic acid monomers; (meth)acrylamide monomers; (meth)acrylonitrile monomers; styrene monomers; and vinyl monomers such as vinyl acetate, N-vinylcarbazole, N-vinylcaprolactam, ethyl vinyl ether, and butyl vinyl ether. Among these, (meth)acrylic acid monomers are preferred from the viewpoint of dispersibility of modified cellulose fibers. Note that "(meth)acrylic" includes both acrylic and methacrylic. For example, "(meth)acrylic acid" includes both acrylic acid and methacrylic acid. "(meth)acrylonitrile" includes both acrylonitrile and methacrylonitrile.

[0103] Examples of monofunctional (meth)acrylic acid monomers include 4-hydroxybutyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tetradecyl (meth)acrylate, octadecyl (meth)acrylate, behenyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, cyclodecyl (meth)acrylate, Examples of the acrylate include tetrafluorooctyl (meth)acrylate, cyclodecylmethyl (meth)acrylate, tricyclodecyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyl (meth)acrylate, naphthyl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (poly)ethylene glycol monomethyl ether (meth)acrylate, (poly)ethylene glycol monolauryl ether (meth)acrylate, (poly)propylene glycol monomethyl ether (meth)acrylate, octafluorooctyl (meth)acrylate, tetrafluoroethyl (meth)acrylate, (meth)acrylate of an ethylene oxide adduct of nonylphenol, (meth)acryloyloxyethyl phosphate, and (meth)acryloyloxyphthalic acid.

[0104] Examples of polyfunctional (meth)acrylic acid monomers include butanediol di(meth)acrylate, hexanediol di(meth)acrylate, tripropylene di(meth)acrylate, tripropylene glycol di(meth)acrylate, poly(ethylene glycol) di(meth)acrylate, poly(propylene glycol) di(meth)acrylate, tri(propylene glycol) di(meth)acrylate, propoxylated neopentyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, bisphenol A di(meth)acrylate, and bisphenol Examples of the ethylene oxide adduct A include di(meth)acrylate, trimethylolpropane propoxylate tri(meth)acrylate, trimethylolpropane ethoxylate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerol propoxylate tri(meth)acrylate, pentaerythritol propoxylate tri(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0105] From the viewpoint of ease of resin production, the content of the polymerizable compound in the composition of the present invention is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, and even more preferably 1000 parts by mass or more, per 100 parts by mass of component (A) in the modified cellulose fiber. From the viewpoint of various mechanical properties of the material, it is preferably 100,000 parts by mass or less, more preferably 50,000 parts by mass or less, even more preferably 20,000 parts by mass or less, and even more preferably 10,000 parts by mass or less, per 100 parts by mass of component (A) in the modified cellulose fiber. The content of each component in the composition of the present invention can be regarded as the blending amount of each component in the composition of the present invention.

[0106] The composition of the present invention may contain other components in addition to those mentioned above, such as plasticizers, crystal nucleating agents, fillers (inorganic fillers, organic fillers), hydrolysis inhibitors, flame retardants, antioxidants, lubricants such as hydrocarbon waxes and anionic surfactants, UV absorbers, antistatic agents, antifogging agents, light stabilizers, pigments, mildew inhibitors, antibacterial agents, foaming agents, surfactants; polysaccharides such as starches and alginic acid; natural proteins such as gelatin, glue, and casein; inorganic compounds such as tannins, zeolites, ceramics, and metal powders; fragrances; flow adjusters; leveling agents; conductive agents; UV dispersants; and deodorizers, within the range that does not impair the effects of the present invention. Similarly, polymeric materials and resin compositions other than the above-mentioned polymerizable compounds may also be added within the range that does not impair the effects of the present invention.

[0107] The composition of the present invention is one in which the change in viscosity over time is suppressed, and therefore suitable applications include various coating agents, adhesives, and paints.

[0108] [Modified cellulose fibers of the present invention] The present invention includes modified cellulose fibers. Preferred embodiments of such modified cellulose fibers include the following.

[0109] Aspect 1: A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less: Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds Here, the anion-modified cellulose fiber of component (A) and the one or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds of component (B) are as described above.

[0110] Aspect 2: Modified cellulose fibers formed by ionic bonding of the following components (A) and (B): Component (A): Anion-modified cellulose fibers; Component (B): Polyether-type tertiary amine represented by the following formula (A2):

[0111]

[0112] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, and AO may be the same or different from each other, and n and m are the average number of moles of AO added, each of which is 1 to 100, and the sum of n and m (n + m) is more than 20 and less than 80.) Here, the anion-modified cellulose fiber of component (A) and the polyether-type tertiary amine represented by formula (A2) of component (B) are as described above.

[0113] Aspect 3: A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 130 or more: Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine Here, the anion-modified cellulose fiber of component (A) and the tertiary diamine of component (B) are as described above.

[0114] In addition, in all of the embodiments 1 to 3, the ratio of component (A) to component (B) and the method for producing the modified cellulose fiber are also as described above.

[0115] In relation to the above-mentioned embodiments, the present invention further discloses the following method for producing the composition, the composition, and the modified cellulose fiber.

[0116] <1> A method for producing a composition containing a modified cellulose fiber and a polymerizable compound, comprising the step of mixing the following components (A) and (B), wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following components (A) and (B), and wherein when the composition is stored, a change in viscosity of the composition after storage is suppressed. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds

[0117] <2> A method for producing the composition according to <1>, further comprising, after the step of mixing component (A) and component (B), a step of mixing the resulting modified cellulose fiber with a polymerizable compound. <3> A method for producing the composition according to <2>, further comprising a step of micronizing the modified cellulose fiber before the step of mixing the modified cellulose fiber with the polymerizable compound. <4> A method for producing the composition according to any one of <1> to <3>, wherein the blending ratio of component (A) to component (B) is preferably 1 part by mass or more, more preferably 10 parts by mass or more, and even more preferably 50 parts by mass or more, per 100 parts by mass of component (A). <5> A method for producing the composition according to any one of <1> to <4>, wherein the blending ratio of component (A) to component (B) is preferably 5,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 500 parts by mass or less, and even more preferably 300 parts by mass or less, per 100 parts by mass of component (A). <6> A method for producing the composition according to any one of <1> to <5>, wherein the amount of the polymerizable compound added is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, and even more preferably 1,000 parts by mass or more, per 100 parts by mass of component (A). <7> A method for producing the composition according to any one of <1> to <6>, wherein the amount of the polymerizable compound added is preferably 100,000 parts by mass or less, more preferably 50,000 parts by mass or less, even more preferably 20,000 parts by mass or less, and even more preferably 10,000 parts by mass or less, per 100 parts by mass of component (A). <8> A method for producing the composition according to any one of <1> to <7>, wherein the amount of the modified cellulose fiber added is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the polymerizable compound. <9> The method for producing a composition according to any one of <1> to <8>, wherein the amount of the modified cellulose fiber added is preferably 100 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the polymerizable compound.<10> A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and component (B), and the viscosity at 25°C is preferably 1 mPa·s or more, more preferably 5 mPa·s or more, and even more preferably 10 mPa·s or more. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds <11> A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and component (B), and the viscosity at 25°C is preferably 10,000 mPa·s or less, more preferably 1,000 mPa·s or less, and even more preferably 300 mPa·s or less. The composition according to <10> <12> A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and component (B), and the composition has a relative viscosity of 50 or more and 200 or less after storage at 40°C for 72 hours. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds <13> The composition according to <12>, wherein the relative viscosity after storage at 40°C for 72 hours is preferably 80 or more, more preferably 90 or more. <14> The composition according to <12> or <13>, wherein the relative viscosity after storage at 40°C for 72 hours is preferably 200 or less, more preferably 130 or less, and even more preferably 110 or less. <15> The composition according to any one of <12> to <14>, wherein the modified cellulose fiber is obtained by adding, per 100 parts by mass of component (A), preferably 1 part by mass or more, more preferably 10 parts by mass or more, and even more preferably 50 parts by mass or more of component (B). <16> The composition according to any one of <12> to <15>, wherein the modified cellulose fiber is obtained by adding, per 100 parts by mass of component (A), preferably 5,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 500 parts by mass or less, and even more preferably 300 parts by mass or less of component (B).<17> The composition according to any one of <12> to <16>, wherein the content of the polymerizable compound in the composition is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, and even more preferably 1,000 parts by mass or more, per 100 parts by mass of component (A). <18> The composition according to any one of <12> to <17>, wherein the content of the polymerizable compound in the composition is preferably 100,000 parts by mass or less, more preferably 50,000 parts by mass or less, even more preferably 20,000 parts by mass or less, and even more preferably 10,000 parts by mass or less, per 100 parts by mass of component (A). <19> The composition according to any one of <12> to <18>, wherein the content of the modified cellulose fiber in the composition is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the polymerizable compound. <20> The composition according to any one of <12> to <19>, wherein the content of the modified cellulose fiber in the composition is preferably 100 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the polymerizable compound. <21> The composition according to any one of <12> to <20>, wherein the content of the modified cellulose fiber in the composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 2% by mass or more. <22> The composition according to any one of <12> to <21>, wherein the content of the modified cellulose fiber in the composition is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 9% by mass or less. <23> The composition according to any one of <12> to <22>, wherein the molecular weight of component (B) is preferably 50 or more, more preferably 100 or more, even more preferably 130 or more, even more preferably 200 or more, even more preferably 500 or more, even more preferably 1000 or more, even more preferably 1400 or more, and even more preferably 1500 or more. <24> The composition according to any one of <12> to <23>, wherein the molecular weight of component (B) is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less.<25> A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and component (B), and wherein the composition has a relative viscosity of 50 or more and 200 or less after storage at 40°C for 72 hours. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds <26> The composition according to <25>, wherein the relative viscosity after storage at 40°C for 72 hours is preferably 80 or more, more preferably 90 or more. <27> The composition according to <25> or <26>, wherein the relative viscosity after storage at 40°C for 72 hours is preferably 200 or less, more preferably 130 or less, and even more preferably 110 or less. <28> A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 to 50,000: Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds <29> The composition according to <28>, wherein the molecular weight of component (B) is preferably 1,400 or more, more preferably 1,500 or more. <30> The composition according to <28> or <29>, wherein the molecular weight of component (B) is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less. <31> The composition according to any one of <28> to <30>, wherein the modified cellulose fiber is obtained by adding, per 100 parts by mass of component (A), preferably 1 part by mass or more, more preferably 10 parts by mass or more, and even more preferably 50 parts by mass or more of component (B). <32> The composition according to any one of <28> to <31>, wherein the modified cellulose fiber in the composition is obtained by adding, per 100 parts by mass of component (A), preferably 5,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 500 parts by mass or less, and even more preferably 300 parts by mass or less of component (B).<33> The composition according to any one of <28> to <32>, wherein the content of the polymerizable compound in the composition is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, and even more preferably 1,000 parts by mass or more, per 100 parts by mass of component (A). <34> The composition according to any one of <28> to <33>, wherein the content of the polymerizable compound in the composition is preferably 100,000 parts by mass or less, more preferably 50,000 parts by mass or less, even more preferably 20,000 parts by mass or less, and even more preferably 10,000 parts by mass or less, per 100 parts by mass of component (A). <35> The composition according to any one of <28> to <34>, wherein the content of the modified cellulose fiber is 0.1% by mass or more and 50% by mass or less. <36> The composition according to any one of <28> to <35>, wherein component (B) is a polyether-type tertiary amine represented by the following formula (A2):

[0118]

[0119] (wherein R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each value being 1 to 100, and the sum of n and m (n + m) is 2 or more and 200 or less.) <37> A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less: Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds <38> The composition according to <37>, wherein the molecular weight of component (B) is preferably 1,400 or more, more preferably 1,500 or more. <39> The composition according to <37> or <38>, wherein the molecular weight of component (B) is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less. <40> A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Polyether-type tertiary amine represented by the following formula (A2):

[0120]

[0121] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each value being 1 to 100, and the sum of n and m (n + m) is more than 20 and less than 80.) <41> The organism according to <40>, wherein the sum of n and m (n + m) is more than 20 and 50 or less. <42> A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Polyether-type tertiary amine represented by the following formula (A2):

[0122]

[0123] (wherein R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each value being 1 to 100, and the sum of n and m (n + m) is more than 20 and less than 80.) <43> The composition according to <42>, wherein the sum of n and m (n + m) is more than 20 and 50 or less. <44> A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding of the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine <45> The composition according to <44>, wherein the tertiary diamine is a tertiary diamine represented by the following formula (A3): R ４ R ５ N-M-NR ６ R ７ (A3) [In the formula, R ４ , R ５ , R ６ and R ７ are monovalent hydrocarbon groups or functional groups represented by the formula (B1), and may be the same or different from each other. M is an alkylene group having 1 to 10 carbon atoms.) <46> R in formula (A3) ４ , R ５ , R ６and R ７is preferably a monovalent hydrocarbon group having from 1 to 22 carbon atoms or a functional group represented by the formula (B1), more preferably a monovalent linear or branched alkyl or alkenyl group having from 1 to 22 carbon atoms, or a functional group represented by the formula (B1). <47> The composition according to <45>, in which the tertiary diamine is one or more selected from the group consisting of polyoxyethylene stearyl propylene diamine, polyoxyethylene lauryl propylene diamine, polyoxyethylene coconut propylene diamine, polyoxyethylene beef tallow propylene diamine, and polyoxyethylene-polyoxypropylene block polymers of ethylene diamine. <48> A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 1,500 or more and 2,000 or less: the modified cellulose fiber is obtained by adding 50 parts by mass or more and 300 parts by mass or less of component (B) to 100 parts by mass of component (A); the content of the modified cellulose fiber in the composition is 2% by mass or more and 9% by mass or less; and the content of the modified cellulose fiber in the composition is 2 parts by mass or more and 10 parts by mass or less to 10 parts by mass or less to 100 parts by mass of the polymerizable compound. Component (A): Anion-modified cellulose fiber Component (B): One or more selected from the group consisting of polyoxyethylene stearyl propylene diamine, and polyoxyethylene-polyoxypropylene block polymers of ethylene diamine <49> A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine <50> A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less.Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds <51> The modified cellulose fiber according to <50>, wherein the molecular weight of component (B) is preferably 1,000 or more, more preferably 1,400 or more, and even more preferably 1,500 or more. <52> The modified cellulose fiber according to <50> or <51>, wherein the molecular weight of component (B) is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less. <53> A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): A polyether-type tertiary amine represented by the following formula (A2):

[0124]

[0125] (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are each the average number of moles of AO added, each value is 1 to 100, and the sum of n and m (n + m) is more than 20 and less than 80.) <54> The modified cellulose fiber according to <53>, wherein the sum of n and m (n + m) is more than 20 and 50 or less. <55> A modified cellulose fiber formed by ionic bonding of the following component (A) and the following component (B) having a molecular weight of 130 or more. Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine <56> The modified cellulose fiber according to <55>, wherein the molecular weight of component (B) is preferably 200 or more, more preferably 500 or more, even more preferably 1000 or more, even more preferably 1400 or more, and even more preferably 1500 or more. <57> The modified cellulose fiber according to <55> or <56>, wherein the molecular weight of component (B) is preferably 50,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less, even more preferably 5,000 or less, and even more preferably 2,000 or less. <58> The composition according to any of <55> to <57>, wherein the tertiary diamine is one or more selected from the group consisting of polyoxyethylene stearyl propylene diamine, polyoxyethylene lauryl propylene diamine, polyoxyethylene coconut propylene diamine, polyoxyethylene beef tallow propylene diamine, and polyoxyethylene-polyoxypropylene block polymers of ethylene diamine. <59> A modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B), wherein the modified cellulose fiber is obtained by adding 50 parts by mass or more and 300 parts by mass or less of component (B) to 100 parts by mass of component (A), and the molecular weight of component (B) is 1500 or more and 2000 or less. Component (A): Anion-modified cellulose fiber Component (B): One or more selected from the group consisting of polyoxyethylene stearyl propylene diamine and polyoxyethylene-polyoxypropylene block polymers of ethylene diamine

[0126] The present invention will be specifically described below with reference to examples. Note that the following examples are merely illustrative of the present invention and are not intended to limit the present invention in any way. Note that "normal pressure" refers to a state in which no pressure or pressure is applied, and "normal temperature" refers to 25°C.

[0127] [Average Fiber Diameter and Average Fiber Length of Cellulose Fibers, (Shortened) Anion-Modified Cellulose Fibers, Modified Cellulose Fibers, and Micronized Modified Cellulose Fibers] Depending on the size of the cellulose fibers to be measured, one of the following two measurement methods was selected. (1) Deionized water or N,N-dimethylformamide (DMF) was added to the cellulose fibers to be measured or a dispersion containing the cellulose fibers to be measured to prepare a dispersion with a DMF content of 0.0001% by mass. The dispersion was dropped onto mica and dried to serve as an observation sample. The fiber height (height difference between the presence and absence of fibers) of the cellulose fibers in the observation sample was measured using an atomic force microscope (AFM) (Nanoscope II Tapping mode AFM manufactured by Digital Instruments; the probe used was a Point Probe (NCH) manufactured by Nanosensors). In this case, 100 cellulose fibers were extracted from a microscopic image in which the cellulose fibers could be observed, and the average fiber diameter was calculated from their fiber heights. The average fiber length was calculated from the distance in the fiber direction.

[0128] (2) Deionized water was added to the cellulose fibers to be measured or a suspension containing the cellulose fibers to be measured to prepare a dispersion with a cellulose fiber content of 0.01% by mass. This dispersion was measured using a wet dispersion type image analysis particle size distribution analyzer (manufactured by Jusco International, product name: IF-3200) under the following conditions: front lens: 2x, telecentric zoom lens: 1x, image resolution: 0.835 μm / pixel, syringe inner diameter: 6515 μm, spacer thickness: 500 μm, image recognition mode: ghost, threshold: 8, analysis sample volume: 1 mL, and sampling: 15%. The cellulose fibers were then approximated as a rectangle, and the length of the minor axis was defined as the fiber diameter and the length of the major axis was defined as the fiber length. Each value was measured for 100 cellulose fibers, and the average was calculated.

[0129] [Anionic Group Content of Anion-Modified Cellulose Fiber] 0.5 g of the cellulose fiber to be measured, with a dry mass of 0.5 g, was placed in a beaker and mixed with deionized water or a 2 / 1 (volume ratio) methanol / deionized water solvent to a total volume of 55 mL. 5 mL of 0.01 M aqueous sodium chloride solution was added to the mixture to prepare a dispersion. The dispersion was stirred until the cellulose fiber to be measured was sufficiently dispersed. 0.1 M hydrochloric acid was added to the dispersion to adjust the pH to 2.5-3. Using an automatic titrator (DKK-TOA Corporation, AUT-701), 0.05 M aqueous sodium hydroxide solution was added dropwise to the dispersion with a waiting time of 60 seconds, and the conductivity and pH were measured every minute. Measurements were continued until the pH reached approximately 11, and a conductivity curve was obtained. The sodium hydroxide titration amount was determined from this conductivity curve, and the anionic group content of the cellulose fiber to be measured was calculated using the following formula: Anionic group content (mmol / g) = [titration amount of aqueous sodium hydroxide solution (mL) × concentration of aqueous sodium hydroxide solution (0.05 M)] / [mass of cellulose fiber to be measured (0.5 g)]

[0130] [Amount of bond and introduction rate of component (B) in modified cellulose fibers and finely divided modified cellulose fibers] The amount of bond of component (B) in modified cellulose fibers and finely divided modified cellulose fibers was determined by the following IR measurement method, and the amount of bond and introduction rate were calculated using the following formula. Specifically, the IR measurement involved measuring the infrared absorption spectrum of the dried cellulose fiber to be measured by the ATR method using an infrared absorption spectrometer (IR) (Nicolet 6700, manufactured by Thermo Fisher Scientific), and the amount of bond and introduction rate of component (B) were calculated using formula A. The following describes the case where the anionic group is a carboxy group, i.e., the case of oxidized cellulose fibers. The following "1720 cm" －１ The "peak intensity of" is the peak intensity derived from carbonyl groups. In the case of anionic groups other than carboxy groups, the value of the wave number can be changed appropriately to calculate the bond amount and introduction rate of component (B). <Formula A> Bond amount of component (B) (mmol / g) = a × (b - c) ÷ b a: Carboxy group content of oxidized cellulose fiber (mmol / g) b: 1720 cm －１c: Peak intensity of 1720 cm of modified cellulose fiber and finely divided modified cellulose fiber －１ <Equation B> Introduction rate of component (B) (mol %) = 100 × f / g, where f is the amount of component (B) bonded (mmol / g), and g is the carboxyl group content of the oxidized cellulose fiber (mmol / g).

[0131] [Content of Each Component] The content of each component other than water was calculated from the blend amount of each component. The content of component (A) contained in the shortened anion-modified cellulose fiber was determined by the solids concentration of the shortened anion-modified cellulose fiber. The glucose moiety content was calculated by assuming that all of the components (A) and (B) blended during the preparation of the modified cellulose fiber were ionically bonded, and the mass of component (A) contained in the blended modified cellulose fiber was regarded as the mass of the glucose moiety. The water content in the dispersion or suspension was measured by Karl Fischer titration using a Mitsubishi Analytech CA-200. The solids concentration of various cellulose fibers was calculated by measuring the moisture concentration in the sample using an infrared moisture meter (Shimadzu Corporation, MOC-120H) and calculating the difference from 100% by mass. The moisture concentration was measured every 30 seconds for 1 g of sample at a constant temperature of 150°C, and the value displayed when the mass loss over 30 seconds reached 0.1% or less was used.

[0132] [Measurement of Electrical Conductivity of Filtrate] The electrical conductivity of the filtrate was measured using a compact electrical conductivity meter (LAQUAtwin EC-33B, manufactured by Horiba, Ltd.).

[0133] [Measurement of the Average Degree of Polymerization of Anion-Modified Cellulose Fiber] The average degree of polymerization of anion-modified cellulose fiber was measured as follows. (1) Preparation of Measurement Solution: 0.06 g (dry mass) of anion-modified cellulose fiber to be measured was precisely weighed and placed in a 50 mL beaker. Water was added to the solution to a solids concentration of 1% by mass. 0.006 g of sodium borohydride was added and stirred at room temperature for 2 hours. 18 g of acetone was then added. The solution was then centrifuged at 10°C, 10,000 G, and 1 minute using a high-speed refrigerated centrifuge (Koki Holdings Co., Ltd., CR21G III) to remove the supernatant. 18 g of ethanol was added to the residue, and the same process of centrifuging and removing the supernatant was repeated three times to obtain a precipitate washed with ethanol. The resulting precipitate was vacuum-dried at 40°C for 12 hours to obtain reduced pulp in which the aldehyde groups in the anion-modified cellulose fiber were reduced.

[0134] (2) Measurement of average degree of polymerization The measurement solution obtained in (1) above was placed in an Ubbelohde viscometer, and allowed to stand in a thermostatic bath (20±0.1)°C for 1 hour. The flow time of the solution (t (seconds)) and the flow time of the copper ethylenediamine solution without cellulose (t ０ (seconds)) was measured, and the intrinsic viscosity [η] (dL / g) was calculated using the following formula:

[0135] [η] = [(t / t ０ -1) / c] / [1+0.28×(t / t ０ −1)] (c: cellulose concentration (g / dL)

[0136] From the obtained intrinsic viscosity [η], the average degree of polymerization (DP) of the anion-modified cellulose fiber was calculated using the following formula: ｖ ) was calculated.

[0137] [η] = 0.094 × 162 × DP ｖ ０．６７

[0138] [Component (A)] Anion-modified cellulose fiber 1 having the physical properties shown in Table 1 was used as a raw material.

[0139]

[0140] Such anion-modified cellulose fiber 1 can be prepared, for example, by carrying out the following TEMPO oxidation treatment and alkaline hydrolysis treatment.

[0141] [TEMPO oxidation treatment] 20 g of bleached coniferous kraft pulp fiber as the raw natural cellulose fiber and 1,980 g of deionized water were weighed into a 2-L PP beaker equipped with a mechanical stirrer and stirring blades and stirred at 25°C and 100 rpm for 30 minutes. Next, 0.26 g of TEMPO, 2.6 g of sodium bromide, and 70.0 g of a 10.5% by mass aqueous solution of sodium hypochlorite were added to the 20 g of pulp fiber in this order. Next, pH stat titration was performed using an automatic titrator, and 0.5 M aqueous sodium hydroxide solution was added dropwise to maintain the pH at 10.5. The reaction was carried out at 25°C for 120 minutes at a stirring speed of 100 rpm. Next, 0.01 M hydrochloric acid was added to the suspension while stirring to adjust the pH to 2. The solids were then filtered off by suction filtration. The solids are dispersed in deionized water and filtered off by suction, and this procedure is repeated until the conductivity of the filtrate reaches 200 μS / cm or less. The resulting solids are then dehydrated to obtain anion-modified cellulose fibers.

[0142] [Alkaline Hydrolysis Treatment] The suspension of anion-modified cellulose fibers (solid content: 14.5 g) obtained by the TEMPO oxidation treatment was diluted with 100 g of deionized water, and 0.14 g of 35% hydrogen peroxide solution (1 part by mass of hydrogen peroxide per 100 parts by mass of the solid content of the raw cellulose fibers) was added thereto. The pH was adjusted to 12 with 1 M aqueous sodium hydroxide solution. Subsequently, alkaline hydrolysis treatment was performed at 80°C for 2 hours (solid content concentration of the anion-modified cellulose fiber suspension: 4.3% by mass). After cooling the suspension to room temperature, 0.01 M hydrochloric acid was added to adjust the pH of the suspension to 2. The solid content of the suspension was filtered off by suction filtration. The solid content was dispersed in deionized water and the suction filtration was repeated until the conductivity of the filtrate reached 200 μS / cm or less. The resulting solid content was dehydrated to obtain anion-modified cellulose fibers 1.

[0143] [Preparation of Shortened Anion-Modified Cellulose Fiber] Anion-modified cellulose fiber 1 having the physical properties listed in Table 1 was subjected to a fiber shortening treatment to obtain short anion-modified cellulose fiber 1 having the physical properties listed in Table 2. Specifically, 227 g (solid content 75 g) of the cake of anion-modified cellulose fiber 1 was taken, and deionized water was added until the solid content concentration changed from the value shown in Table 2 to 5% by mass. The resulting suspension was stirred at 95°C for the time listed in Table 2 to obtain an aqueous suspension of short anion-modified cellulose fiber. The resulting suspension was centrifuged using a high-speed refrigerated centrifuge (CR21G III, manufactured by Koki Holdings Co., Ltd.) at 25°C, 10,000 G, and for 1 minute to obtain short anion-modified cellulose fiber 1 listed in Table 2 as a precipitate.

[0144]

[0145] Examples 1 to 7 and Comparative Examples 1 to 2 [Preparation of modified cellulose fiber dispersion] Shortened anion-modified cellulose fiber 1 was placed in a beaker, and component (B) or an amine not corresponding to component (B) (collectively referred to as "modifying compound") and an organic solvent were added so that the content calculated from the blending amounts of each component other than water was the content shown in Table 3. The mixture was then stirred at room temperature for 2 hours to obtain modified cellulose fiber suspensions 1 to 8 shown in Table 3. In each modified cellulose fiber, the bond between component (A) and component (B) was an ionic bond. Note that the water in Table 3 is the water associated with shortened anion-modified cellulose fiber 1.

[0146]

[0147] The resulting suspension was subjected to a micronization treatment 10 times at 150 MPa using a high-pressure homogenizer (Nanovaita L-ES, manufactured by Yoshida Kikai Kogyo Co., Ltd.) to obtain dispersions 1 to 8 of micronized modified cellulose fibers listed in Table 4.

[0148]

[0149] *: The content (mass%) of glucose moieties in the finely divided modified cellulose fibers in the dispersion.

[0150] [Preparation of compositions containing modified cellulose fiber and polymerizable compound] To the resulting dispersion, an acrylic monomer (4-hydroxybutyl acrylate, 4HBA) as a polymerizable compound was added to obtain the compositions shown in Tables 5 and 6, and the mixture was stirred at room temperature for 1 hour. Then, the volatile components, ethanol and water, were distilled off using a rotary evaporator (manufactured by BUCHI), to obtain the compositions shown in Tables 5 and 6 (Examples 1 to 7 and Comparative Examples 1 and 2).

[0151] Reference Example As a reference example, a composition containing only a polymerizable compound was prepared.

[0152]

[0153]

[0154] *: The content (mass%) of glucose moieties in the finely divided modified cellulose fiber in the composition. The molecular weights of polyoxyethylene stearylamine, M2005, polyoxyethylene stearyl propylene diamine, and EOPO-added ethylene diamine are number average molecular weights.

[0155] The following reagents and compounds were used without any special purification. [Reagents] Ethanol: Ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) [Polymerizable compound] 4-Hydroxybutyl Acrylate: 4-Hydroxybutyl Acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) [Modifying compounds] Primary amines Octadecylamine: Octadecylamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Mw=270) M2005: Methoxypoly(oxyethylene / oxypropylene)-2-propylamine (manufactured by HUNTSMAN, Jeffamine M2005, Mn=2000, EO:PO=6:29) Tertiary amines Dimethyloctadecylamine: N,N-dimethyl-n-octadecylamine (manufactured by Tokyo Chemical Industry Co., Ltd., Mw=298) Polyoxyethylenestearylamine (manufactured by Aoki Oil & Fat Co., Ltd.: Brownon) S-230, Mn = 1590. This compound is a polyether-type tertiary amine corresponding to the structure shown in the above formula (A2).) Polyoxyethylene stearyl propylene diamine: (Aoki Oil & Fat Co., Ltd.: Brownon DR-86-56, Mn = 2526. This compound is a tertiary diamine corresponding to the structure shown in the above formula (A3).) EOPO-added ethylene diamine: (Adeka Corporation: Pluronic (registered trademark) TR-913R, Mn = 5900. This compound is a tertiary diamine corresponding to the structure shown in the above formula (A3).) Quaternary ammonium compounds TBAH: tetrabutylammonium hydroxide (10% methanol solution) (Tokyo Chemical Industry Co., Ltd., 10% by mass methanol solution, Mw = 259)

[0156] The compositions (Examples 1 to 7, Comparative Examples 1 and 2, and Reference Example) shown in Tables 5 and 6 were evaluated as follows. [Viscosity Measurement] Using a rheometer (MCR300, manufactured by Anton Paar) and a measuring jig: CP50-1, the viscosity of the composition to be evaluated was measured at a measurement temperature of 25°C as follows: shear rate 0.1 s －１ From the 1000s －１ The shear rate was increased stepwise over 3 minutes to 1000 s. －１ From 0.1 seconds －１ The shear rate was then reduced stepwise over 3 minutes to 0.1 s. －１From the 1000s －１ The shear rate was increased stepwise over 3 minutes until the shear rate reached 10 s －１ The viscosity at the time when the viscosity reached this value was taken as the viscosity of the composition.

[0157] [Evaluation of Viscosity Change] The viscosity of the composition immediately after preparation was measured by the method described above. Furthermore, as an accelerated storage test, the prepared composition was stored in a thermostatic chamber at 40°C for 72 hours or at 80°C for 24 hours, and then cooled to 25°C. The viscosity of the composition was measured by the method described above. The relative viscosity after storage (relative value, with the viscosity immediately after preparation set to 100) was calculated using the following formula: Relative viscosity after storage (relative value, with the viscosity immediately after preparation set to 100) = 100 × (viscosity after storage / viscosity of composition immediately after preparation). The viscosity immediately after preparation and after heated storage were compared to confirm the effect of inhibiting viscosity change. The closer the relative viscosity value after storage is to 100, the smaller the viscosity change of the composition after storage can be evaluated to be.

[0158] [Transmittance Immediately After Preparation of Composition] The light transmittance (%, hereinafter referred to as transmittance) immediately after preparation of the composition in each example and comparative example was measured as follows. The higher the transmittance, the better the dispersibility of the modified cellulose fiber in the composition. The transmittance measurement was carried out at room temperature and atmospheric pressure. Specifically, 3 mL of the composition to be measured was placed in a quartz cell with an optical path length of 10 mm, and the transmittance at a wavelength of 660 nm was immediately measured using a double-beam spectrophotometer (Hitachi High-Tech Science Corporation, "U-2910"). The transmittance of each composition was determined using 4HBA as a blank (i.e., transmittance 100%). The higher the transmittance of a composition, the better the coatability of the composition, the transparency of the composition and the cured film after coating and curing, the smoothness and uniformity of the cured film, and the mechanical properties of the cured film can be expected to be.

[0159] [Discussion] Tables 5 and 6 show that the compositions obtained by the manufacturing method of the present invention, which contain the specified modified cellulose fibers, show little change in viscosity after storage. In particular, when stored at 40°C for 72 hours, the compositions obtained in all Examples exhibited excellent effects, with relative viscosities within the range of 100±24. Furthermore, when stored at 80°C for 24 hours, the relative viscosities of the compositions obtained in the Comparative Examples were 8 and 3138, respectively, while the relative viscosities of the compositions obtained in the Examples were within the range of 80 to 1105, demonstrating that viscosity change was suppressed even when stored at a high temperature of 80°C.

[0160] More specifically, Table 5 shows that in the examples (Example 1 and Comparative Example 1) using a tertiary amine and a primary amine having the same alkyl chain, the viscosity was lower after heated storage than immediately after preparation. However, the viscosity decrease rate was smaller in Example 1, suggesting that the use of the tertiary amine dimethyloctadecylamine prevented the viscosity decrease of the composition. Comparing Comparative Example 1 and the Reference Example, it was found that the viscosity immediately after preparation of the composition increased significantly in Comparative Example 1 compared to the Reference Example, which was a composition containing only acrylic monomer. This is thought to be because the molecular weight of the modifying compound used in Comparative Example 1 was relatively small, causing the modified cellulose fibers to disperse while tightly entangled with each other in the acrylic monomer, resulting in an increased viscosity of the composition. Subsequently, the Michael addition reaction between the octadecylamine modifying compound and the acrylic monomer caused the octadecylamine to detach from the composition over time, which led to the strong aggregation of the modified cellulose fibers, weakening the thickening effect and decreasing the viscosity.

[0161] On the other hand, in examples using amines with relatively large molecular weights (Example 2 and Comparative Example 2), it was found that the viscosity of the composition was higher after heated storage than immediately after preparation. However, the viscosity increase rate was smaller in Example 2, suggesting that the use of the tertiary amine polyoxyethylenestearylamine was able to suppress the increase in viscosity of the composition. Comparing Comparative Example 2 with the Reference Example, it was found that the viscosity of Comparative Example 2 was not significantly different from that of the Reference Example with respect to the viscosity immediately after preparation of the composition. This is thought to be because the molecular weight of the modifying compound used in Comparative Example 2 was relatively large, so the interaction of the modified cellulose fibers in the acrylic monomer was weak, and they were dispersed in a state close to isolation from each other. Subsequently, due to the Michael addition reaction between the modifying compound M2005 and the acrylic monomer, M2005 was released from the composition over time, causing aggregation of the modified cellulose fibers, and the thickening effect was thought to be exhibited over time.

[0162] Furthermore, the transmittance immediately after preparation of the compositions obtained by the production method of the present invention was 90% or higher for all of the compositions obtained in Examples 2 to 7. These results demonstrate that the use of a polyether-type tertiary amine, a tertiary diamine, or a quaternary ammonium compound as component (B) enables the production of compositions with higher transmittance.

[0163] The same effect is expected even if the modified cellulose fiber is made by ionic bonding of component (A) with component (B), which is cellulose fiber to which phosphate groups have been introduced by the method described in Japanese Patent No. 7196051.

[0164] The present invention also encompasses the following methods for suppressing viscosity changes in a composition, and compositions containing modified cellulose fibers and a polymerizable compound. [1] A method for suppressing viscosity changes in a composition containing modified cellulose fibers and a polymerizable compound, comprising the step of mixing the modified cellulose fibers with the polymerizable compound, wherein the modified cellulose fibers are formed by ionic bonding of the following components (A) and (B): Component (A): Anion-modified cellulose fibers; Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds. [2] A method for suppressing viscosity changes in a composition according to [1] above, further comprising the step of micronizing the modified cellulose fibers before the step of mixing the modified cellulose fibers with the polymerizable compound. [3] A method for suppressing viscosity changes in a composition according to [1] or [2] above, wherein the modified cellulose fibers are obtained by adding 1 to 5,000 parts by mass of component (B) to 100 parts by mass of component (A). [4] A method for suppressing a change in viscosity of the composition according to any one of [1] to [3] above, wherein the content of the polymerizable compound in the composition is 10 parts by mass or more and 100,000 parts by mass or less per 100 parts by mass of component (A). [5] A method for suppressing a change in viscosity of the composition according to any one of [1] to [4] above, wherein the content of the modified cellulose fiber in the composition is 0.1% by mass or more and 50% by mass or less. [6] A method for suppressing a change in viscosity of the composition according to any one of [1] to [5] above, wherein the molecular weight of component (B) is 50 or more and 50,000 or less. [7] A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is a modified cellulose fiber formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 1,000 or more and 50,000 or less. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds [8] The composition according to [7] above, wherein the content of the polymerizable compound is 10 parts by mass or more and 100,000 parts by mass or less per 100 parts by mass of component (A). [9] The composition according to [7] above or [8] above, wherein the content of the modified cellulose fiber is 0.1% by mass or more and 50% by mass or less.

[0165] The composition of the present invention is one in which the change in viscosity over time is suppressed, and therefore it can be suitably used as a variety of coating agents, adhesives, and paints.

Claims

1. A method for producing a composition containing a modified cellulose fiber and a polymerizable compound, comprising the step of mixing the following components (A) and (B): the modified cellulose fiber is formed by ionic bonding between the following components (A) and (B), and the method is characterized in that, when the composition is stored, a change in viscosity of the composition after storage is suppressed. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds 2. A method for producing the composition according to claim 1, further comprising the step of mixing the resulting modified cellulose fiber with a polymerizable compound after the step of mixing component (A) and component (B).

3. A method for producing the composition according to claim 2, further comprising the step of micronizing the modified cellulose fiber before the step of mixing the modified cellulose fiber with the polymerizable compound.

4. A method for producing a composition according to any one of claims 1 to 3, wherein the compounding ratio of component (A) to component (B) is 1 part by mass or more and 5,000 parts by mass of component (B) per 100 parts by mass of component (A).

5. A method for producing a composition according to any one of claims 1 to 4, wherein the amount of polymerizable compound added is 10 parts by mass or more and 100,000 parts by mass or less per 100 parts by mass of component (A).

6. A method for producing a composition according to any one of claims 1 to 5, wherein the amount of modified cellulose fiber added is 0.1 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the polymerizable compound.

7. A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B), and the composition has a relative viscosity of 50 or more and 200 or less after storage at 40°C for 72 hours. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds 8. The composition according to claim 7, wherein the modified cellulose fiber is obtained by adding 1 part by mass or more and 5,000 parts by mass or less of component (B) to 100 parts by mass of component (A).

9. The composition according to claim 7 or 8, wherein the content of the polymerizable compound in the composition is 10 parts by mass or more and 100,000 parts by mass or less per 100 parts by mass of component (A).

10. The composition according to any one of claims 7 to 9, wherein the content of the modified cellulose fiber in the composition is 0.1 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the polymerizable compound.

11. The composition according to any one of claims 7 to 10, wherein the content of the modified cellulose fiber in the composition is 0.1% by mass or more and 50% by mass or less.

12. The composition according to any one of claims 7 to 11, wherein the molecular weight of component (B) is 50 or more and 50,000 or less.

13. A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B), and the composition has a relative viscosity of 50 or more and 200 or less after storage at 40°C for 72 hours. Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds 14. A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less: Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds.

15. The composition according to claim 14, wherein the modified cellulose fiber is obtained by adding 1 part by mass or more and 5,000 parts by mass or less of component (B) to 100 parts by mass of component (A).

16. The composition according to claim 14 or 15, wherein the content of the polymerizable compound in the composition is 10 parts by mass or more and 100,000 parts by mass or less per 100 parts by mass of component (A).

17. The composition according to any one of claims 14 to 16, wherein the content of the modified cellulose fiber in the composition is 0.1% by mass or more and 50% by mass or less.

18. The composition according to any one of claims 14 to 17, wherein component (B) is a polyether-type tertiary amine represented by the following formula (A2): (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are the average number of moles of AO added, each value is 1 to 100, and the sum of n and m (n+m) is 2 or more and 200 or less.) 19. A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B) having a molecular weight of 500 or more and 50,000 or less: Component (A): Anion-modified cellulose fiber Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds.

20. A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding of the following components (A) and (B): Component (A): Anion-modified cellulose fiber; Component (B): Polyether-type tertiary amine represented by the following formula (A2): (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are the average number of moles of AO added, each value is 1 to 100, and the sum of n and m (n+m) is more than 20 and less than 80.) 21. A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Polyether-type tertiary amine represented by the following formula (A2): (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are the average number of moles of AO added, each value is 1 to 100, and the sum of n and m (n+m) is more than 20 and less than 80.) 22. A composition containing a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber Component (B): Tertiary diamine 23. A composition comprising a modified cellulose fiber and a polymerizable compound, wherein the modified cellulose fiber is formed by ionic bonding between the following components (A) and (B): Component (A): Anion-modified cellulose fiber; Component (B): Tertiary diamine.

24. Modified cellulose fibers formed by ionic bonding of the following component (A) with the following component (B) having a molecular weight of 500 or more and 50,000 or less: Component (A): Anion-modified cellulose fibers; Component (B): One or more compounds selected from the group consisting of tertiary amines and quaternary ammonium compounds.

25. Modified cellulose fiber formed by ionic bonding of the following component (A) and the following component (B): Component (A): Anion-modified cellulose fiber; Component (B): Polyether-type tertiary amine represented by the following formula (A2): (In the formula, R is a monovalent hydrocarbon group, AO is a divalent alkylene oxide group, AO may be the same or different, n and m are the average number of moles of AO added, each value is 1 to 100, and the sum of n and m (n+m) is more than 20 and less than 80.) 26. Modified cellulose fiber formed by ionic bonding of the following component (A) and the following component (B) having a molecular weight of 130 or more: Component (A): Anion-modified cellulose fiber; Component (B): Tertiary diamine.