Resin composition

Abstract

A resin composition according to the present invention contains (A) a modified cellulose fiber, (B) a urethane-modified epoxy resin, and (C) an epoxy resin other than the urethane-modified epoxy resin. The resin composition according to the present invention can be used as an adhesive for a metal member or the like of a structure, and the resin composition according to the present invention can be provided as an adhesive that has excellent mechanical strength.

Description

resin composition

[0001] The present invention relates to a resin composition.

[0002] In recent years, environmentally friendly technologies have been attracting attention, and against this technological background, materials using cellulose fibers, which are naturally occurring biomass, have been attracting attention.

[0003] For example, Patent Document 1 discloses an adhesive composition containing a water-insoluble resin and fine cellulose fibers containing ionic groups and / or a fine cellulose fiber composite formed by bonding modifying groups to fine cellulose fibers containing ionic groups. Patent Document 2 also discloses an adhesive composition containing fine fibrous cellulose and a matrix resin that satisfies the following conditions (A) to (E): (A) a number-average fiber diameter of 2 nm to 500 nm, (B) an average aspect ratio of 10 to 1,000, (C) a cellulose I-type crystalline structure, (D) anionic functional groups, and (E) a specific polyetheramine is bonded to some or all of the anionic functional groups described in (D).

[0004] JP 2019-94388 A JP 2018-44097 A

[0005] The performance required of an adhesive varies depending on the physical properties of the objects to be bonded. The present invention relates to a resin composition that, when used to bond metal members of a structure, has excellent mechanical strength, for example, improved elongation in a shear adhesion test.

[0006] The present invention relates to the following items [1] to

[20] . [1] A resin composition comprising (A) modified cellulose fiber, (B) a urethane-modified epoxy resin, and (C) an epoxy resin other than the urethane-modified epoxy resin. [2] The composition according to item [1], wherein the (A) modified cellulose fiber has a cellulose type I crystal structure and has an average fiber diameter of 1 nm to 300 nm. [3] The composition according to item [1] or [2], wherein the (A) modified cellulose fiber is formed by bonding a modifying group to an anion-modified cellulose fiber, and the modifying group is a group containing one or more selected from the group consisting of (i) a hydrocarbon group having 3 or more carbon atoms, (ii) a silicone chain, and (iii) an alkylene oxide chain. [4] The composition according to item [3], wherein the modifying group is bonded to the anionic group of the anion-modified cellulose fiber via an ionic bond and / or a covalent bond. [5] The composition according to any one of [1] to [4] above, wherein the epoxy resin other than the urethane-modified epoxy resin (C) is at least one selected from the group consisting of bisphenol-type epoxy resins, rubber-modified epoxy resins, alicyclic epoxy resins, glycidylamine-type epoxy resins, polysulfide-modified epoxy resins, chelate-modified epoxy resins, trisphenolmethane-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-modified epoxy resins, epoxidized products of aliphatic polyols or derivatives thereof, polyether-modified epoxy resins, polyfunctional aromatic epoxy resins, and hydrogenated bisphenol-type epoxy resins. [6] The composition according to any one of [1] to [5] above, wherein the content of the urethane-modified epoxy resin (B) in the composition is 1% by mass or more and less than 80% by mass, and the content of the epoxy resin other than the urethane-modified epoxy resin (C) in the composition is 1% by mass or more and less than 80% by mass. [7] The composition according to any one of [1] to [6] above, which is obtained by mixing a mixture of (A) modified cellulose fiber and (B) urethane-modified epoxy resin with (C) an epoxy resin other than urethane-modified epoxy resin. [8] The composition according to any one of [1] to [6] above, which is obtained by mixing a mixture of (B) urethane-modified epoxy resin and (C) an epoxy resin other than urethane-modified epoxy resin with (A) modified cellulose fiber.[9] The composition according to any one of [1] to [6] above, obtained by mixing a mixture of (A) modified cellulose fiber and (C) an epoxy resin other than a urethane-modified epoxy resin with (B) a urethane-modified epoxy resin.

[10] An adhesive comprising the composition according to any one of [1] to [9] above.

[0007]

[11] The adhesive according to

[10] above, wherein the adhesive is a structural adhesive.

[12] The adhesive according to

[10] or

[11] above, further comprising a filler other than (A) modified cellulose fiber.

[13] The adhesive according to any one of

[10] to

[12] above, used to bond vehicle assemblies.

[14] A method for bonding vehicle assemblies, comprising a step of bonding vehicle assemblies using the adhesive according to any one of

[10] to

[13] above.

[15] A method for producing a resin composition containing (B) a urethane-modified epoxy resin, and (C) an epoxy resin other than a urethane-modified epoxy resin, comprising: Step 1: mixing (A) modified cellulose fiber and (B) urethane-modified epoxy resin, and Step 2: mixing the mixture obtained in Step 1 with (C) an epoxy resin other than a urethane-modified epoxy resin.

[16] A method for producing a resin composition containing (B) a urethane-modified epoxy resin, and (C) an epoxy resin other than a urethane-modified epoxy resin, comprising the following Step 3 or Step 4: Step 3: Mixing (A) modified cellulose fiber, (B) urethane-modified epoxy resin, and (C) an epoxy resin other than urethane-modified epoxy resin. Step 4: Mixing (B) urethane-modified epoxy resin and (C) an epoxy resin other than urethane-modified epoxy resin (Step 4-1), and mixing the resulting composition with (A) modified cellulose fiber (Step 4-2).

[17] A method for producing a resin composition containing (B) urethane-modified epoxy resin and (C) an epoxy resin other than urethane-modified epoxy resin, comprising: Step 5: Mixing (A) modified cellulose fiber and (C) an epoxy resin other than urethane-modified epoxy resin; and Step 6: Mixing the composition obtained in Step 5 with (B) urethane-modified epoxy resin.

[18] A method for improving the breaking elongation of a structural adhesive, comprising mixing (A) modified cellulose fiber and (B) urethane-modified epoxy resin.

[19] An adhesive kit comprising a container containing the adhesive according to any one of

[10] to

[13] above.

[20] An adhesive kit comprising: a first container containing the composition according to any one of [1] to [9]; and a second container containing a curing agent. Detailed Description of the Invention

[0008] According to the present invention, it is possible to provide a resin composition that has excellent mechanical strength when used to bond metal members of a structure or the like.

[0009] Although the detailed mechanism by which the resin composition of the present invention exerts such an effect is unknown, it is presumed that the presence of the modified cellulose fiber at the interface between the object to be bonded and the resin improves the adhesion of the resin to the bonding surface and improves elongation, even if the bonding surface of the object to be bonded (e.g., metal and / or plastic) is somewhat less smooth.

[0010] The resin composition of the present invention contains (A) modified cellulose fibers, (B) a urethane-modified epoxy resin, and (C) an epoxy resin other than the urethane-modified epoxy resin.

[0011] [(A) Modified cellulose fiber] The modified cellulose fiber in the present invention is a cellulose fiber to which a modifying group having a specific structure is bonded. The modifying group is a group (-CH) at the C6 position of a glucose unit constituting the cellulose fiber or a part or all of the hydroxy groups of the cellulose fiber. ２ Preferably, the hydroxyl group (OH) is attached to the carboxyl group that has been converted to a carboxyl group.

[0012] (Anion-modified cellulose fibers) As cellulose fibers to which a modifying group is bonded, anion-modified cellulose fibers are preferred from the viewpoint of ease of bonding of the modifying group. Anion-modified cellulose fibers are cellulose fibers having an anionic group, for example, 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 viewpoint of availability and effectiveness, anion-modified cellulose fibers having a carboxy group as the anionic group are preferred, and a group (-CH ２ Anion-modified cellulose fibers (referred to as "oxidized cellulose fibers") in which the anionic groups (OH) are selectively converted to carboxy groups are more preferred. The counter ions of the anionic groups are preferably protons.

[0013] The anionic group content in the anion-modified cellulose fiber 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 stable introduction of modifying groups and increasing adhesive strength through the introduction of modifying groups. Furthermore, from the viewpoint of improving handleability, the content is preferably 3 mmol / g or less, more preferably 2.5 mmol / g or less, more preferably 2 mmol / g or less, more preferably 1.9 mmol / g or less, even more preferably 1.8 mmol / g or less, more preferably 1.7 mmol / g or less, and even more preferably 1.5 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.

[0014] The bond of a modifying group to an anionic group of an anion-modified cellulose fiber means that the modifying group is bonded to an anionic group, preferably a carboxy group, possessed by the anion-modified cellulose fiber. Examples of the bond between the modifying group and the anionic group include an ionic bond and / or a covalent bond. Examples of the covalent bond include an amide bond, an ester bond, and a urethane bond, with an amide bond being preferred. Therefore, a preferred embodiment of the modified cellulose fiber of the present invention is one in which the modifying group is bonded to the anionic group of the anion-modified cellulose fiber via an ionic bond and / or a covalent bond.

[0015] (Modifying Group) Examples of the modifying group include those containing (i) a hydrocarbon group having 3 or more carbon atoms, (ii) a silicone chain, and (iii) an alkylene oxide chain. These modifying groups may be bonded (introduced) to the cellulose fiber either alone or in combination of two or more.

[0016] (i) Hydrocarbon Groups Having 3 or More Carbon Atoms Examples of hydrocarbon groups having 3 or more carbon atoms include monovalent hydrocarbon groups, such as chain saturated hydrocarbon groups, chain unsaturated hydrocarbon groups, cyclic saturated hydrocarbon groups, and (heterocyclic) aromatic hydrocarbon groups. From the viewpoint of increasing the adhesive strength when the composition is used as an adhesive, the number of carbon atoms in the hydrocarbon group is 3 or more, preferably 8 or more, and more preferably 10 or more, and from the same viewpoint, is preferably 30 or less, more preferably 22 or less, and even more preferably 18 or less. The hydrocarbon group may have a substituent as described below, and a portion of the hydrocarbon group may be substituted with a hydrogen nitride group.

[0017] The chain saturated hydrocarbon group is preferably one having 3 to 30 carbon atoms, and specific examples include a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, a tert-pentyl group, an isopentyl group, a hexyl group, an isohexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a dodecyl group, a tridecyl group, a tetradecyl group, an octadecyl group, a docosyl group, and an octacosanyl group.

[0018] The chain unsaturated hydrocarbon group is preferably one having 3 to 30 carbon atoms, and specific examples include a propenyl group, a butenyl group, an isobutenyl group, an isoprenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, and an octadecenyl group.

[0019] The cyclic saturated hydrocarbon group is preferably one having 3 to 20 carbon atoms, and specific examples include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cyclododecyl group, a cyclotridecyl group, a cyclotetradecyl group, and a cyclooctadecyl group.

[0020] Examples of the aromatic hydrocarbon group include an aryl group and an aralkyl group. The aryl group and the aralkyl group may be substituted with a substituent described below or may be unsubstituted. Examples of the heterocyclic aromatic hydrocarbon group include an imidazole group.

[0021] The total number of carbon atoms in the aryl group is preferably 6 or more and 24 or less, and specific examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a biphenyl group, a triphenyl group, a terphenyl group, and groups in which these groups are substituted with the substituents described below.

[0022] The total number of carbon atoms in the aralkyl group is preferably 7 or more and 24 or less, and specific examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylpentyl group, a phenylhexyl group, a phenylheptyl group, a phenyloctyl group, and groups in which these groups are substituted with the substituents described below. The total number of carbon atoms in the imidazole group is preferably 3 or more and 24 or less, and specific examples of the imidazole group include an imidazole group, a methylimidazole group, an ethylimidazole group, a propylimidazole group, a 2-phenylimidazole group, a benzimidazole group, and groups in which these groups are substituted with a substituent.

[0023] (ii) Silicone Chain The silicone chain is a monovalent group having a siloxane bond as the main chain, and may further include an alkylene group. The silicone chain may have a substituent, as described below.

[0024] (iii) Alkylene oxide chain The alkylene oxide chain is a structure containing a (co)polymer of ethylene oxide (EO) or propylene oxide (PO), and is preferably one or more structures selected from the group consisting of a structure containing a polymer of EO (EO chain), a structure containing a polymer of PO (PO chain), and a structure containing a copolymer in which EO and PO are polymerized randomly or in a block form ((EO / PO) chain). The alkylene oxide chain may further have a hydrocarbon group bonded thereto.

[0025] Examples of the alkylene oxide chain include those represented by the following formula:

[0026]

[0027] (In the formula, R １ is a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or —CH ２ CH (CH ３ ) NH ２ represents a group. EO and PO are present randomly or in a block form, a represents the average number of moles of EO added and is 0 or a positive number, and b represents the average number of moles of PO added and is 0 or a positive number, except when both a and b are 0.

[0028] In the above formula, a represents the average number of moles of EO added, and from the viewpoints of availability and affinity with the resin, it is preferably 0 or more, more preferably 1 or more, and even more preferably 2 or more; from the same viewpoints, it is preferably 100 or less, more preferably 70 or less.

[0029] In the above formula, b represents the average number of moles of PO added, and from the viewpoint of affinity with the resin, it is preferably 0 or more, more preferably 1 or more, and even more preferably 3 or more, and from the viewpoint of availability, it is preferably 50 or less, more preferably 40 or less.

[0030] R in the above formula １ Specific examples of the hydrocarbon group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, a tert-pentyl group, an isopentyl group, a hexyl group, and an isohexyl group.

[0031] The formula weight (molecular weight) of the alkylene oxide chain is preferably 500 or more, more preferably 1,000 or more, and is preferably 10,000 or less, more preferably 7,000 or less. The formula weight of the alkylene oxide chain can be determined by calculation from the average number of moles added when producing an amine compound having an alkylene oxide chain, which will be described later.

[0032] From the viewpoint of increasing adhesive strength, the PO content (mol %) in the (EO / PO) chain is preferably 1 mol % or more, more preferably 5 mol % or more, and from the same viewpoint, it is preferably 100 mol % or less, more preferably 95 mol % or less, and even more preferably 90 mol % or less. The PO content in the (EO / PO) chain can be determined by calculation from the average number of moles added when producing an amine compound having an alkylene oxide chain, which will be described later. The alkylene oxide chain may have the following substituents.

[0033] (iv) Further Substituents The modifying group 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, and sec-butoxycarbonyl. alkoxycarbonyl groups having 1 to 6 carbon atoms in the alkoxy group, such as a tert-butoxycarbonyl group, a pentyloxycarbonyl group, or an isopentyloxycarbonyl group; halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; acyl groups having 1 to 6 carbon atoms, such as an acetyl group or a propionyl group; aralkyl groups; aralkyloxy groups; alkylamino groups having 1 to 6 carbon atoms; dialkylamino groups having an alkyl group with 1 to 6 carbon atoms; and a hydroxy group.

[0034] [Method for producing modified cellulose fibers] Modified cellulose fibers can be produced, for example, by introducing anionic groups into raw cellulose fibers to prepare anionically modified cellulose fibers (step a), and then bonding modifying groups to the anionic groups of the anionically modified cellulose fibers (step b).

[0035] (Step a) Raw Cellulose Fibers As the raw material cellulose fibers for the anion-modified cellulose fibers, 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; bacterial cellulose, etc., and these can be used alone or in combination of two or more.

[0036] 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.

[0037] 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 5,000 μm or less, more preferably 3,000 μm or less. The average fiber length of the raw cellulose fibers can be measured according to the method described in the Examples below.

[0038] Treatment Method (1) Introducing Carboxy Groups as Anionic Groups into Cellulose Fibers Examples of methods for introducing carboxy groups into cellulose fibers include a method of oxidizing hydroxy groups of cellulose fibers to convert them into carboxy groups, and a method of reacting hydroxy groups of cellulose fibers with at least one selected from the group consisting of compounds having carboxy groups, acid anhydrides of compounds having carboxy groups, and derivatives thereof.

[0039] Examples of methods for oxidizing the hydroxy groups of cellulose fibers include those described in JP 2015-143336 A and JP 2015-143337 A, 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 group at C6 of the glucose of the cellulose fiber structural unit is selectively converted to a carboxy group, thereby producing the oxidized cellulose fibers described above.

[0040] The compound having a carboxy group used to introduce a carboxy group into cellulose fibers is not particularly limited, but specific examples include halogenated acetic acids. Examples of halogenated acetic acids include chloroacetic acid. The acid anhydrides of compounds having a carboxy group and their derivatives used to introduce a carboxy group into cellulose fibers are not particularly limited, but examples include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, and adipic anhydride, imidized products of acid anhydrides of compounds having a carboxy group, and derivatives of acid anhydrides of compounds having a carboxyl group. These compounds may be substituted with a hydrophobic group.

[0041] (2) Introducing sulfonic acid groups or (phosphite) groups into cellulose fibers as anionic groups: Methods for introducing sulfonic acid groups into cellulose fibers include adding sulfuric acid to cellulose fibers and heating them. Methods for introducing (phosphite) groups into cellulose fibers include mixing a powder or aqueous solution of (phosphite) phosphorous or a (phosphite) derivative with dry or wet cellulose fibers, or adding an aqueous solution of (phosphite) phosphorous or a (phosphite) derivative to a dispersion of cellulose fibers. When these methods are employed, dehydration and heating treatments are generally performed after mixing or adding a powder or aqueous solution of (phosphite) phosphorous or a (phosphite) derivative.

[0042] (Step b) Introduction of modifying groups into the anionic groups of anion-modified cellulose fibers is achieved by reacting the anion-modified cellulose fibers with a compound for introducing modifying groups into anionic groups (referred to as a "modifying compound"). Regarding the method for introducing the modifying group, (1) JP 2015-143336 A can be referenced when introducing the modifying group via an ionic bond, and (2) JP 2015-143337 A can be referenced when introducing the modifying group via an amide bond. After completion of step b, post-treatment may be appropriately performed to remove unreacted compounds, etc. Examples of post-treatment methods that can be used include filtration, centrifugation, and dialysis.

[0043] (1) Aspect of introduction via ionic bond When introducing a modifying group via an ionic bond, anion-modified cellulose fiber and a modifying compound are mixed, and an ionic bond is formed between the anionic group contained in the anion-modified cellulose fiber and the amino group of the modifying compound. Specifically, when oxidized cellulose fiber is used as the anion-modified cellulose fiber and a primary amine having the above-mentioned modifying group is used as the modifying compound, the above-mentioned modifying group can be introduced via an ionic bond to the carboxy group at the C6 position of glucose constituting the cellulose fiber, as shown in the following formula (wherein, C ６ is the carbon atom at the 6th position of the glucose that constitutes the cellulose fiber, and R is a modifying group.

[0044]

[0045] Modifying Compound The modifying compound used in this embodiment may be any compound capable of introducing a desired modifying group, and preferred examples include the above-mentioned amine compounds having a hydrocarbon group, a silicone chain, or an alkylene oxide chain, phosphonium compounds, and guanidino group-containing compounds.

[0046] Amine Compound The amine compound is, for example, an amine compound having the aforementioned hydrocarbon group, the aforementioned silicone chain, or the aforementioned alkylene oxide chain as a modifying group, and such hydrocarbon group or the like is introduced into the anion-modified cellulose fiber via an ionic bond to become a modifying group in the modified cellulose fiber.

[0047] The amine compound may be any of a primary amine, a secondary amine, a tertiary amine, and a quaternary ammonium compound. From the viewpoint of reactivity, preferred anion components of the quaternary ammonium compound include halogen ions such as chloride ions and bromide ions, hydrogen sulfate ions, perchlorate ions, tetrafluoroborate ions, hexafluorophosphate ions, trifluoromethanesulfonate ions, and hydroxy ions.

[0048] Amine Compound Having a Hydrocarbon Group Specific examples of the amine compound having a hydrocarbon group include primary to tertiary amines, such as diethylamine, triethylamine, propylamine, dipropylamine, butylamine, dibutylamine, hexylamine, 2-ethylhexylamine, dihexylamine, trihexylamine, octylamine, dioctylamine, trioctylamine, dodecylamine, didodecylamine, stearylamine, distearylamine, monoethanolamine, diethanolamine, triethanolamine, oleylamine, aniline, octadecylamine, dimethylbehenylamine, benzylamine, naphthylamine, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, and 1-(3-aminopropyl)imidazole.

[0049] Examples of quaternary ammonium compounds include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetraethylammonium chloride, tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), tetrabutylammonium chloride, lauryltrimethylammonium chloride, dilauryldimethyl chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, cetyltrimethylammonium chloride, and alkylbenzyldimethylammonium chloride.

[0050] The amine compound having a hydrocarbon group may be a commercially available product or may be prepared according to a known method.

[0051] Amine Compound Having Silicone Chain Examples of such amine compounds include those having a structure in which an amino group is bonded to a silicone chain skeleton via an alkylene group or the like. In this specification, such amine compounds may be referred to as "amino-modified silicones." Commercially available amino-modified silicones can be used, or they can be prepared according to known methods. Only one type of amino-modified silicone may be used, or two or more types may be used.

[0052] As amino-modified silicones, from the viewpoint of performance, TSF4703 (kinematic viscosity: 1000, amino equivalent: 1600) and TSF4708 (kinematic viscosity: 1000, amino equivalent: 2800) manufactured by Momentive Performance Materials, Inc., SS-3551 (kinematic viscosity: 1000, amino equivalent: 1600), SF8457C (kinematic viscosity: 1200, amino equivalent: 1800), SF8417 (kinematic viscosity: 1200, amino equivalent: 1700), BY16-209 (kinematic viscosity: 500, amino equivalent: 1800) manufactured by Dow Corning Toray Silicone Co., Ltd., and B Preferred examples include Y16-892 (kinematic viscosity: 1500, amino equivalent: 2000), BY16-898 (kinematic viscosity: 2000, amino equivalent: 2900), FZ-3760 (kinematic viscosity: 220, amino equivalent: 1600), KF8002 (kinematic viscosity: 1100, amino equivalent: 1700), KF867 (kinematic viscosity: 1300, amino equivalent: 1700), KF-864 (kinematic viscosity: 1700, amino equivalent: 3800), BY16-213 (kinematic viscosity: 55, amino equivalent: 2700), and BY16-853U (kinematic viscosity: 14, amino equivalent: 450) manufactured by Shin-Etsu Chemical Co., Ltd. In parentheses, the kinematic viscosity is measured at 25°C (unit: mm ２ / s), and the unit of amino equivalent is g / mol.

[0053] Amine Compound Having Alkylene Oxide Chain In the amine compound, the alkylene oxide chain and the nitrogen atom of the amine compound are preferably bonded directly or via a linking group. The linking group is preferably a hydrocarbon group, and includes an alkylene group having preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms. Preferred examples of such alkylene groups include ethylene and propylene groups.

[0054] Examples of the amine having an alkylene oxide chain include amines represented by the following formula (i):

[0055]

[0056] In formula (i), R １ , a and b are R in the formula showing an example of the alkylene oxide chain. １ , a and b.

[0057] Amine compounds having alkylene oxide chains can be prepared according to known methods. For example, desired amounts of ethylene oxide and propylene oxide can be added to a propylene glycol alkyl ether, followed by aminating the hydroxyl group terminal. If necessary, the alkyl ether can be cleaved with an acid to convert the terminal to a hydrogen atom. For these production methods, see JP-A-3-181448, and details of such amine compounds are described, for example, in JP-A-6105139.

[0058] As the amine compound having an alkylene oxide chain, for example, commercially available products can be suitably used. Specific examples include Jeffamine M-2070, Jeffamine M-2005, Jeffamine M-2095, Jeffamine M-1000, Jeffamine M-600, Surfoamine B200, Surfoamine L100, Surfoamine L200, Surfoamine L207, Surfoamine L300, Surfoamine B-100, XTJ-501, XTJ-506, XTJ-507, XTJ-508, M3000, Jeffamine ED-900, Jeffamine ED-2003, Jeffamine D-2000, Jeffamine D-4000, XTJ-510, Jeffamine T-3000, and Jeffamine ED-2003, all manufactured by HUNTSMAN. T-5000, XTJ-502, XTJ-509, XTJ-510, etc., and SUNBRIGHT MEPA-10H, SUNBRIGHT MEPA-20H, SUNBRIGHT MEPA-50H, SUNBRIGHT MEPA-10T, SUNBRIGHT MEPA-12T, SUNBRIGHT MEPA-20T, SUNBRIGHT MEPA-30T, SUNBRIGHT MEPA-40T, etc. manufactured by NOF Corporation. These may be used alone or in combination of two or more.

[0059] Guanidino Group-Containing Compound The guanidino group-containing compound is, for example, a guanidine compound having the aforementioned hydrocarbon group, the aforementioned silicone chain, or the aforementioned alkylene oxide chain as a modifying group, and such hydrocarbon group or the like is introduced into the anion-modified cellulose fiber via an ionic bond to become the modifying group in the modified cellulose fiber. Examples of the guanidino group-containing compound include diphenylguanidine, ditolylguanidine, 1,2,3-triphenylguanidine, aminoguanidine, and arginine.

[0060] Reaction conditions, etc. From the viewpoint of reactivity, the amount of modifying compound used is preferably an amount such that the number of amino groups in the modifying compound is 0.01 mol or more, more preferably 0.1 mol or more, even more preferably 0.5 mol or more, even more preferably 0.7 mol or more, and even more preferably 1 mol or more, per mol of carboxy groups in the oxidized cellulose fiber, and from the viewpoint of product purity, the amount is preferably an amount such that the number of amino groups is 50 mol or less, more preferably 20 mol or less, and even more preferably 10 mol or less. When the modifying compound has multiple amino groups, it is used so that the total number of moles of amino groups is the above-mentioned number of moles.

[0061] It is preferable to use a solvent when mixing. As the solvent, it is preferable to select a solvent in which the compound to be used dissolves, and examples thereof include methanol, ethanol, isopropanol (IPA), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide, tetrahydrofuran (THF), acetone, methyl ethyl ketone (MEK), cyclohexanone, ethyl acetate, acetonitrile, dichloromethane, chloroform, toluene, acetic acid, 1-methoxy-2-propanol (PGME), water, etc., and these can be used alone or in combination of two or more.

[0062] The temperature during mixing is preferably 0°C or higher, more preferably 5°C or higher, and even more preferably 10°C or higher, from the viewpoint of the reactivity of the compound. Furthermore, from the viewpoint of suppressing discoloration of the modified cellulose fiber, it is preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower. The mixing time can be appropriately set depending on the type of compound and solvent used, but from the viewpoint of the reactivity of the compound, it is preferably 0.01 hour or higher, more preferably 0.1 hour or higher, and from the viewpoint of productivity, it is preferably 48 hours or lower, more preferably 24 hours or lower.

[0063] (2) Aspect of introduction via an amide bond When introducing a modifying group via an amide bond, anion-modified cellulose fiber and a modifying compound may be mixed in the presence of a known condensing agent, thereby forming an amide bond between the anionic group contained in the anion-modified cellulose fiber and the amino group of the modifying compound. Specifically, when oxidized cellulose fiber is used as the anion-modified cellulose fiber and a primary amine having the above-mentioned modifying group is used as the modifying compound, the above-mentioned modifying group can be introduced via an amide bond to the carboxy group at the C6 position of glucose constituting the cellulose fiber, as shown in the following formula (wherein ６ is the carbon atom at the 6th position of the glucose that constitutes the cellulose fiber, and R is a modifying group.

[0064]

[0065] Modifying Compound The modifying compound used in this embodiment may be any compound capable of introducing a desired modifying group, and preferred examples include the above-mentioned amine compounds having a hydrocarbon group, an alkylene oxide chain, or a silicone chain.

[0066] Amine Compound The amine compound is, for example, an amine compound having the aforementioned hydrocarbon group, the aforementioned alkylene oxide chain, or the aforementioned silicone chain as a modifying group, and such a hydrocarbon group or the like is introduced into the anion-modified cellulose fiber via an amide bond to become a modifying group in the modified cellulose fiber.

[0067] Examples of the amine compound include primary amines and secondary amines. Specific examples of the amine compound include primary amines and secondary amines among amine compounds having a hydrocarbon group, amine compounds having an alkylene oxide chain, and amine compounds having a silicone chain, which are exemplified in the above-mentioned "(1) Aspect of introduction via ionic bond."

[0068] Reaction Conditions From the viewpoint of enhancing reactivity and adhesive strength, the amount of modifying compound used is preferably an amount such that the number of amino groups in the modifying compound is 0.05 mol or more, more preferably 0.1 mol or more, even more preferably 0.2 mol or more, even more preferably 0.3 mol or more, and even more preferably 0.5 mol or more per mol of carboxy groups in the oxidized cellulose fiber, and from the viewpoint of product purity and dischargeability, an amount such that the number of amino groups is 50 mol or less, more preferably 20 mol or less, and even more preferably 10 mol or less. When the modifying compound has multiple amino groups, it is used so that the total number of moles of amino groups is the above-mentioned number of moles.

[0069] The condensing agent is not particularly limited, but includes those described on page 116 of Synthetic Chemistry Series: Peptide Synthesis (Maruzensha) or those described in Tetrahedron, 57, 1551 (2001), such as 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (hereinafter sometimes referred to as "DMT-MM"). It is also possible to carry out the reaction by heat treatment alone without using a condensing agent.

[0070] The amidation reaction may or may not involve the use of a solvent. When a solvent is used, it is preferable to select a solvent that dissolves the compound to be used. Specific examples of the solvent include the solvents exemplified in the above-mentioned "(1) Mode of introduction via ionic bond."

[0071] The reaction time and reaction temperature in the amidation reaction can be appropriately selected depending on the type of compound and solvent used, etc., but are preferably 1 to 24 hours, more preferably 10 to 20 hours, from the viewpoint of reaction rate. Furthermore, the reaction temperature is preferably 0°C or higher, more preferably 5°C or higher, and even more preferably 10°C or higher, from the viewpoint of reactivity. Furthermore, from the viewpoint of product quality, such as coloration, the reaction temperature is preferably 200°C or lower, more preferably 80°C or lower, and even more preferably 30°C or lower.

[0072] (Micronization step) By micronizing the cellulose fibers at any stage of the production method of the modified cellulose fibers (for example, before step a, before step b, and after step b), the cellulose fibers of the micrometer scale can be micronized to the nanometer scale. Reducing the average fiber diameter to the nanometer size is preferable because it improves dispersibility in the resin.

[0073] The micronization treatment can be carried out by a known micronization treatment method. For example, to obtain 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.

[0074] Examples of the medium include water, 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; ketones having 2 to 4 carbon atoms, such as ethyl acetate and butyl acetate; 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 solvents can be used alone or in combination of two or more. The amount of medium used should be an effective amount capable of dispersing the modified cellulose fibers. The amount used is preferably at least 1 times, more preferably at least 2 times, and more preferably at most 500 times, more preferably at most 200 times the weight of the modified cellulose fibers.

[0075] 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.

[0076] [Properties of Modified Cellulose Fiber] The main properties of the modified cellulose fiber of the present invention are as follows.

[0077] (Crystalline Structure) The modified cellulose fiber has a cellulose type I crystal structure from the viewpoint of enhancing adhesive strength. Here, the cellulose type I crystal structure is derived from the raw cellulose fiber, preferably the raw natural cellulose fiber. 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 enhancing adhesive strength. 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 the cellulose fiber is 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. Note that cellulose type I refers to the crystalline form of natural cellulose, and cellulose type I crystallinity refers to the proportion of crystalline regions in the entire cellulose fiber. The presence or absence of the cellulose type I crystal structure can be determined by the presence of a peak at 2θ = 22.6° in X-ray diffraction measurement.

[0078] (Average fiber diameter) The modified cellulose fiber is preferably one that has been subjected to a micronization treatment to have a nanometer size. Therefore, from the viewpoints of handleability, availability, and cost, the average fiber diameter of the modified cellulose fiber is preferably 1 nm or more, more preferably 2 nm or more, and from the viewpoints of improving handleability, dispersibility, and adhesive strength, it is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, even more preferably 120 nm or less, and even more preferably 20 nm or less. Therefore, one embodiment of a preferred modified cellulose fiber in the present invention is one that has a cellulose type I crystal structure and has an average fiber diameter of 1 nm or more and 300 nm or less.

[0079] (Average fiber length) The average fiber length of the modified cellulose fiber is preferably 10 nm or more, more preferably 30 nm or more, and even more preferably 50 nm or more from the viewpoint of increasing adhesive strength, and is 1000 nm or less, preferably 800 nm or less, more preferably 500 nm or less, even more preferably 300 nm or less, and even more preferably less than 150 nm from the viewpoint of increasing dischargeability and elongation at break.

[0080] (Average aspect ratio) From the viewpoint of increasing adhesive strength, the average aspect ratio of the modified cellulose fiber is preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more. On the other hand, from the viewpoint of increasing dischargeability and adhesive strength, it is preferably 300 or less, more preferably 200 or less, even more preferably 150 or less, even more preferably 100 or less, and even more preferably 70 or less. By setting the average fiber length and average aspect ratio within the above ranges, excellent adhesion is achieved between materials with different physical properties (for example, materials with different linear expansion coefficients). The average fiber diameter, average fiber length, and average aspect ratio of the modified cellulose fiber can be determined by the method described in the examples below.

[0081] (Modifying group bond amount and introduction rate) The modifying group bond amount in the modified cellulose fiber is preferably 0.01 mmol / g or more from the viewpoint of increasing adhesive strength, and from the same viewpoint, is preferably 3.0 mmol / g or less. When any two or more modifying groups are simultaneously introduced into the modified cellulose fiber as modifying groups, the modifying group bond amount is preferably within the above range.

[0082] From the viewpoint of dispersibility, the introduction rate of the modifying group in the modified cellulose fiber is preferably 10 mol% or more, the higher the better, and preferably 100 mol%. When any two or more types of modifying groups are simultaneously introduced as the modifying groups, the total introduction rate is preferably within the above range as long as it does not exceed the upper limit of 100 mol%.

[0083] The bonded amount and introduction rate of the modifying group can be adjusted by the type and amount of the modifying compound, the reaction temperature, the reaction time, the type of solvent, etc. The bonded amount (mmol / g) and introduction rate (mol%) of the modifying group refer to the amount and rate of the modifying group introduced (bonded) to the anionic group in the modified cellulose fiber. For example, when the anionic group is a carboxy group, the bonded amount and introduction rate of the modifying group in the modified cellulose fiber are calculated by the method described in the Examples below.

[0084] [Resin] Examples of the resin in the resin composition of the present invention include epoxy resins other than the urethane-modified epoxy resin (B) and the urethane-modified epoxy resin (C), and the resin composition of the present invention may contain the resins of component (B) and component (C).

[0085] The urethane-modified epoxy resin of component (B) may be any resin having a urethane bond and two or more epoxy groups in the molecule. For example, a resin obtained by reacting a compound having a urethane bond obtained by addition reaction of a polyhydroxy compound having a hydroxy group (such as polyether polyol, polyester polyol, polybutadiene polyol, polyolefin polyol, or an adduct of a hydroxycarboxylic acid and an alkylene oxide) with a polyisocyanate compound having an isocyanate group (such as tolylene diisocyanate, diphenylmethane diisocyanate, or naphthalene diisocyanate) with a bisphenol-type epoxy resin (an epoxy compound having a hydroxy group). Commercially available urethane-modified epoxy resins may be used, including, for example, the ADEKA Resin EPU series from ADEKA Corporation and the EPOKY (registered trademark) series from Mitsui Chemicals, Inc.

[0086] The preferred viscosity range of the urethane-modified epoxy resin of component (B) is, from the viewpoint of suppressing dripping after application, preferably 1,000 mPa· / 25°C or higher, more preferably 3,000 mPa· / 25°C or higher, and even more preferably 5,000 mPa· / 25°C or higher. From the viewpoint of application and dischargeability, the preferred viscosity range is 1,000,000 mPa· / 25°C or lower, more preferably 750,000 mPa· / 25°C or lower, and even more preferably 500,000 mPa· / 25°C or lower. Furthermore, the preferred epoxy equivalent range of the urethane-modified epoxy resin of component (B) is, from the viewpoint of forming a cured product with excellent adhesive properties, preferably 100 g / equivalent or higher, more preferably 125 g / equivalent or higher, and even more preferably 150 g / equivalent or higher. From the viewpoint of the mechanical strength of the cured product, the preferred range is 500 g / equivalent or lower, more preferably 400 g / equivalent or lower, and even more preferably 350 g / equivalent or lower.

[0087] The "epoxy resin other than urethane-modified epoxy resin" of component (C) is an epoxy resin that does not fall under the category of component (B) above, among epoxy resins in the field of the present invention.

[0088] More specifically, the epoxy resin in component (C) includes at least one selected from the group consisting of bisphenol-type epoxy resins, rubber-modified epoxy resins, alicyclic epoxy resins, glycidylamine-type epoxy resins, polysulfide-modified epoxy resins, chelate-modified epoxy resins, trisphenolmethane-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-modified epoxy resins, aliphatic epoxy resins such as epoxidized aliphatic polyols or their derivatives, polyether-modified epoxy resins, polyfunctional aromatic epoxy resins, and hydrogenated bisphenol-type epoxy resins. Examples of alicyclic epoxy resins include glycidyl ester-type epoxy resins, glycidylamine-type epoxy resins, phenol novolac-type epoxy resins, and alicyclic epoxy resins having an ester skeleton. Furthermore, examples of epoxy resins in component (C) include cyclohexane-type epoxy resins, cyclohexanedimethanol-type epoxy resins, glycidylamine-type epoxy resins, and epoxy resins that are epoxidized polybutadiene polyols. These resins are referred to herein as "general-purpose epoxy resins." Of these, from the viewpoint of improving adhesive strength and tensile strength, aliphatic epoxy resins are preferred, bisphenol-type epoxy resins are more preferred, one or more selected from bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins are even more preferred, and bisphenol A-type epoxy resins are even more preferred.

[0089] Specific examples of general-purpose epoxy resins include jER807, jER828, jER828US, jER828EL, jER825, jER630, and jER630LSD manufactured by Mitsubishi Chemical Corporation; and ADEKA RESIN EP-4100, ADEKA RESIN EP-4300E, ADEKA RESIN EP-4400, ADEKA RESIN EP-4901E, ADEKA RESIN EP-4000, ADEKA RESIN EP-4000S, ADEKA RESIN EP-4005, ADEKA RESIN EPR-1415-1, ADEKA RESIN EPR-2000, ADEKA RESIN EPR-2007, ADEKA RESIN EP-49-10N, and ADEKA RESIN EPR-1415-2 manufactured by ADEKA Corporation. Resin EP-49-10P2, Adeka Resin EP-49-23, etc.; FLEP-50, FLEP-60, etc., manufactured by Toray Fine Chemical Co., Ltd.; Epolite 40E, Epolite 100E, Epolite 200E, Epolite 400E, Epolite 70P, Epolite 200P, Epolite 400P, Epolite 1500NP, Epolite 1600, Epolite 80MF, Epolite 4000, Epolite 3002(N), etc., manufactured by Kyoeisha Chemical Co., Ltd.; Denacol EX-201, Denacol EX-201-IM, Denacol EX-252, Denacol EX-991L, etc., manufactured by Nagase ChemteX Corporation. These may be used alone or in combination of two or more.

[0090] The preferred viscosity range of the general-purpose epoxy resin is, from the viewpoint of suppressing dripping after application, preferably 1,000 mPa / 25°C or more, more preferably 3,000 mPa / 25°C or more, and even more preferably 5,000 mPa / 25°C or more, while, from the viewpoint of application property and discharge property, it is preferably 1,000,000 mPa / 25°C or less, more preferably 750,000 mPa / 25°C or less, and even more preferably 500,000 mPa / 25°C or less.

[0091] Furthermore, epoxy-based diluents containing epoxy groups, known as reactive diluents, can also be used as the epoxy resin of component (C). Because these reactive diluents have lower viscosities than component (C), incorporating an appropriate amount of reactive diluent can lower the viscosity of the resin composition. Specific examples of such reactive diluents include monofunctional n-butanol glycidyl ether, butyl glycidyl ether, butylphenyl glycidyl ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, tetrahydrofurfuryl glycidyl ether, furfuryl glycidyl ether, trimethoxysilyl glycidyl ether, other higher alcohol glycidyl ethers, and methacrylic acid glycidyl esters; and multifunctional diluents such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol glycidyl ether, and dimer acid diglycidyl esters. The preferred viscosity range of these reactive diluents is, from the viewpoint of being able to form a cured product having excellent adhesive properties, preferably 15 mPa / 25°C or more, more preferably 20 mPa / 25°C or more, and even more preferably 30 mPa / 25°C or more, while, from the viewpoint of handleability, it is preferably 3,000 mPa / 25°C or less, more preferably 2,000 mPa / 25°C or less, and even more preferably 1,000 mPa / 25°C or less. Reactive diluents are commercially available, and examples thereof include ADEKA GLYCILOR ED-503, ADEKA GLYCILOR ED-503G, ADEKA GLYCILOR ED-506, ADEKA GLYCILOR ED-523T, and ADEKA GLYCILOR ED-505, manufactured by ADEKA Corporation.

[0092] As component (C), a general-purpose epoxy resin and a reactive diluent may be used in combination. When used in combination, the ratio of the two is, from the viewpoints of coatability and dischargeability, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more of the reactive diluent per 100 parts by mass of the general-purpose epoxy resin. On the other hand, from the viewpoints of suppressing dripping after application and being able to form a cured product having excellent adhesive properties, the ratio of the reactive diluent is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.

[0093] Fillers known in the field of the present invention can be blended in order to adjust the viscosity of the composition of the present invention, improve the mechanical properties after curing, etc. Examples of such fillers include fillers other than (A) modified cellulose fibers, such as calcium carbonate, talc, magnesia, calcium silicate, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, alumina, zircon, graphite, barium sulfate, mica, kaolin, wollastonite, clay, mica, feldspar, syenite, chlorite, bentonite, montmorillonite, barite, cristobalite, dolomite, quartz, diatomaceous earth, aluminum silicate, barium carbonate, magnesium carbonate, zinc carbonate, mineral fibers, Examples include textile fibers, glass fibers, aramid pulp, boron fibers, carbon fibers, phosphates, silica such as crystalline silica, amorphous silica, fused silica, fumed silica, calcined silica, precipitated silica, and pulverized silica powder, silica sand, rosestone, cement, resin powder such as polyethylene, calcium oxide, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, titanium dioxide, hollow inorganic beads such as hollow ceramic beads and hollow glass beads, hollow organic beads made of polyester resin, glass beads, metal powder, bitumen, etc. These may be used alone or in combination of two or more.

[0094] In addition, various additives such as curing agents and curing accelerators, reaction retarders, antioxidants, antioxidants, pigments, dyes, plasticizers, silane coupling agents, adhesion promoters, flame retardants, antistatic agents, ultraviolet absorbers, surfactants, dispersants, dehydrating agents, thermosetting resins other than epoxy resins, thermoplastic resins, etc. may be used in appropriate combinations as needed.

[0095] The curing agent or curing accelerator may be any of a wide variety of agents commonly used for curing epoxy resins. Examples of the curing agent include dicyandiamide, acid anhydrides, phenolic resin curing agents, polyamine compounds, polymercaptan compounds, isocyanate compounds, and organic acids. In the present invention, from the viewpoint of storage stability, one or more selected from dicyandiamide, acid anhydrides, polyamine compounds, and polymercaptan compounds are preferred.

[0096] Dicyandiamide is H ２ N-C (NH ２ )=N-CN, and its melting point is usually 205-215°C, and 207-212°C for highly pure ones.

[0097] The acid anhydride is preferably an acid anhydride of an unsaturated dicarboxylic acid having a radically polymerizable unsaturated bond, more preferably at least one selected from aromatic acid anhydrides, cyclic aliphatic acid anhydrides, and aliphatic acid anhydrides, and even more preferably an acid anhydride that is liquid at 25°C.

[0098] Specific examples of the acid anhydride include those of fumaric acid, maleic acid, succinic acid, dodecenylsuccinic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, itaconic acid, citraconic acid, etc., preferably those of maleic acid, tetrahydrophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, more preferably one or more selected from tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride. Examples of the organic phosphorus compound include triphenylphosphine, etc., and examples of the quaternary ammonium salt include tetraethylammonium bromide, tetrabutylammonium bromide, etc.

[0099] Examples of quaternary phosphonium salts include tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, tetrabutylphosphonium myristate, tetrabutylphosphonium palmitate, and salts of a tetrabutylphosphonium cation with an anion such as bicyclo[2.2.1]heptane-2,3-dicarboxylic acid, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, 4-chlorobenzenesulfonic acid, and dodecylbenzenesulfonic acid.

[0100] Examples of the organic metal salt include tin octoate, zinc octoate, dibutyltin dilaurate, aluminum acetylacetone complex, etc. Examples of the boron compound include boron trifluoride, triphenylborate, etc. These acid anhydrides can be used alone or in combination of two or more.

[0101] Examples of the polyamine compound include diamine compounds and triamine compounds, and one or more compounds selected from aliphatic diamines, aromatic diamines, and dialicyclic amines are preferred.

[0102] Examples of polymercaptan compounds include polyhydric alcohol esters of mercaptocarboxylic acids, esters of monomercaptan monohydric alcohols containing polycarboxylic acids, compounds having a mercaptan group at the end of a polypropylene glycol or polyethylene glycol chain, other ester-containing polymercaptans described in U.S. Patent No. 4,126,505, propoxylated ether polythiols described in U.S. Patent No. 4,092,293, polymercaptan-containing resins having a molecular weight of 750 to 7,000 described in U.S. Patent No. 3,258,495, dimercaptopolysulfide polymers described in U.S. Patent No. 2,919,255, and thiolated oligomeric triglycerides. Among these, polyhydric alcohol esters of mercaptocarboxylic acids are preferred.

[0103] Preferred examples of the polyhydric alcohol ester of mercaptocarboxylic acid include trimethylolpropane trimercaptopropionate, trimethylolpropane trithiogluconate, pentaerythritol tetramercaptopropionate, pentaerythritol tetrathiogluconate, and trimethylolethane trimercaptopropionate.

[0104] The curing accelerator can be appropriately selected depending on the type of curing agent, but examples of curing accelerators for dicyandiamide include ureas, imidazoles, Lewis acid catalysts, etc., and among these, it is preferable to use ureas. Examples of ureas include 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), toluene bis(dimethylurea), 4,4'-methylene bis(phenyldimethylurea), 3-phenyl-1,1-dimethylurea, dichlorodimethylurea, phenyldimethylurea, etc.

[0105] As the curing accelerator for the acid anhydride, tertiary amines, tertiary amine salts, imidazoles, organic phosphorus compounds, quaternary ammonium salts, quaternary phosphonium salts, organic metal salts, boron compounds, etc. can be used.

[0106] [Resin Composition of the Present Invention] The amount of resin in the composition of the present invention, calculated as the blending amount, is preferably 10% by mass or more and preferably 97% by mass or less from the viewpoint of increasing adhesive strength. When a filler is not contained, the amount of resin, calculated as the blending amount, is more preferably 50% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more from the viewpoint of increasing adhesive strength, while from the viewpoint of cost, it is more preferably 95% by mass or less, even more preferably 92% by mass or less. When a filler is contained, the amount of resin, calculated as the blending amount, is more preferably 10% by mass or more, even more preferably 20% by mass or more, and even more preferably 30% by mass or more from the viewpoint of increasing adhesive strength, while from the viewpoint of cost, it is more preferably 95% by mass or less, even more preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0107] Regarding the combination of the contents of component (B) and component (C) in the composition of the present invention, from the viewpoint of achieving both adhesive strength and tensile strength, the content of component (B) is preferably 1% by mass or more and less than 80% by mass, and the content of component (C) is 1% by mass or more and less than 90% by mass. When no filler is contained, from the above viewpoint, the content of component (B) is more preferably 5% by mass or more and less than 65% by mass, and the content of component (C) is 35% by mass or more and less than 85% by mass, and even more preferably the content of component (B) is 10% by mass or more and less than 60% by mass, and the content of component (C) is 40% by mass or more and less than 80% by mass.

[0108] When a filler is contained, from the above viewpoints, it is more preferable that the content of component (B) is 3% by mass or more and 55% by mass or less, and the content of component (C) is 15% by mass or more and less than 55% by mass, and even more preferable that the content of component (B) is 5% by mass or more and 45% by mass or less, and the content of component (C) is 20% by mass or more and 50% by mass or less.

[0109] The content ratio of the component (C) to the component (B) in the composition of the present invention [(C) / (B)] is preferably 0.4 or more and 15 or less, more preferably 0.5 or more and 12 or less, and even more preferably 0.6 or more and 10 or less, from the viewpoint of achieving both adhesive strength and tensile strength.

[0110] The mass ratio of cellulose fiber to component (B) in the composition of the present invention, converted into the blending amount, is preferably 0.001 or more, more preferably 0.005 or more, and even more preferably 0.01 or more, from the viewpoint of increasing the breaking elongation, while from the viewpoint of viscosity, it is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, and even more preferably 0.10 or less.

[0111] The mass ratio of cellulose fiber to resin in the composition of the present invention, converted into blend amounts, is preferably 0.01 / 100 or more, more preferably 0.05 / 100 or more, even more preferably 0.1 / 100 or more, even more preferably 0.3 / 100 or more, and even more preferably 0.5 / 100 or more from the viewpoint of increasing adhesive strength, while from the viewpoint of viscosity, it is preferably 30 / 100 or less, more preferably 20 / 100 or less, even more preferably 15 / 100 or less, even more preferably 10 / 100 or less, even more preferably 7 / 100 or less, and even more preferably 5 / 100 or less. Note that the mass of cellulose fiber here refers to the portion of the modified cellulose fiber excluding the modifying group, i.e., the mass of the cellulose fiber portion.

[0112] When the composition of the present invention contains a curing agent and / or a curing accelerator, the preferred amount of curing agent cannot be generalized because it is adjusted depending on the environment in which the adhesive is used (heating temperature, heating time) and the influence of other components, but the amount of these components, as the total amount of both, converted into the blending amount, is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, per 100 parts by mass of resin, and is preferably 80 parts by mass or less, more preferably 70 parts by mass or less.

[0113] When the composition of the present invention contains a filler, the amount of the filler added is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 30 parts by mass or more, per 100 parts by mass of the resin, from the viewpoint of cost; on the other hand, from the viewpoint of strength, the amount of the filler added is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less.

[0114] The viscosity of the composition of the present invention is preferably 1,000 mPa·s / 25°C or higher, more preferably 3,000 mPa·s / 25°C or higher, and even more preferably 5,000 mPa·s / 25°C or higher, from the viewpoint of suppressing dripping after application, while from the viewpoint of application property and discharge property, it is preferably 1,000,000 mPa·s / 25°C or lower, more preferably 750,000 mPa·s / 25°C or lower, and even more preferably 500,000 mPa·s / 25°C or lower. Here, the viscosity is measured at a shear rate of 1 s according to JIS-K2220. －１ The measurement was carried out under the following conditions.

[0115] The resin composition of the present invention may further contain a solvent, and the viscosity of the resin composition can be adjusted to the desired level using the solvent. Usable solvents include, for example, dimethylformamide, ethyl acetate, methyl methacrylate, ethanol, isopropanol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide, tetrahydrofuran (THF), a diester of succinic acid and triethylene glycol monomethyl ether, acetone, methyl ethyl ketone (MEK), acetonitrile, dichloromethane, chloroform, toluene, 1-methoxy-2-propanol (PGME), and acetic acid. These solvents can be used alone or in combination of two or more. When a solvent is used, the amount thereof is, for example, preferably 50 parts by mass or more, more preferably 100 parts by mass or more, relative to 100 parts by mass of the resin, and preferably 5,000 parts by mass or less, more preferably 2,000 parts by mass or less.

[0116] [Method for producing resin composition] The resin composition of the present invention can be produced, for example, by mixing the modified cellulose fiber with the resin, etc. Furthermore, a solvent, a curing agent, and other components can be mixed as needed. When a filler is optionally blended, a step α can be further included after the step of mixing the modified cellulose fiber with the resin, etc. Step α: Step of adding and mixing a filler

[0117] When a one-component adhesive is prepared, the following steps A and B can be further included after the step of mixing the modified cellulose fiber with the resin or the like, or after step α if a filler is optionally added: Step A: Adding and mixing a curing agent and / or a curing accelerator; and Step B: Adding and mixing a reactive diluent.

[0118] The method for mixing the components constituting the adhesive is not particularly limited, and includes a general method, for example, a method using a mixer such as a planetary mixer. In the final step of producing the resin composition, a degassing treatment can be optionally performed.

[0119] One preferred embodiment of the method for producing an adhesive of the present invention is a method for producing a resin composition containing (B) a urethane-modified epoxy resin and (C) an epoxy resin other than the urethane-modified epoxy resin, the method comprising: Step 1: mixing (A) modified cellulose fiber with (B) the urethane-modified epoxy resin; and Step 2: mixing the mixture obtained in Step 1 with (C) an epoxy resin other than the urethane-modified epoxy resin.

[0120] According to this production method, the resin composition of the present invention can be obtained by mixing a mixture of (A) modified cellulose fiber and (B) urethane-modified epoxy resin with (C) an epoxy resin other than the urethane-modified epoxy resin. When multiple types of resins are used as component (C), a first resin as component (C) may be mixed with a mixture of components (A) and (B), and then a second resin as component (C) may be mixed.

[0121] In this production method, it is preferable to perform a dispersion treatment during mixing in step 1 from the viewpoint of further improving dispersibility. Examples of dispersion treatment include dispersion treatment using a grinder such as a mass colloider, or dispersion treatment using a high-pressure homogenizer in a medium. From the viewpoint of dispersion uniformity, dispersion treatment using a high-pressure homogenizer is preferred. The medium is similar to the description of the medium above. When a medium is used, it is preferable to distill off the solvent using an evaporator to improve the mixing properties in step 2. In this production method, the mass ratio of modified cellulose fiber to component (B) in step 1, converted into the blending amount, is preferably 0.005 or more, more preferably 0.010 or more, and even more preferably 0.030 or more from the viewpoint of improving elongation at break. On the other hand, from the viewpoint of viscosity, it is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, even more preferably 0.10 or less, and even more preferably 0.07 or less.

[0122] Another preferred embodiment of the method for producing a resin composition of the present invention is a method for producing a resin composition containing (B) a urethane-modified epoxy resin and (C) an epoxy resin other than the urethane-modified epoxy resin, comprising the following step 3 or step 4: Step 3: A step of mixing (A) modified cellulose fiber, (B) urethane-modified epoxy resin, and (C) an epoxy resin other than the urethane-modified epoxy resin; and Step 4: A step of mixing (B) urethane-modified epoxy resin and (C) an epoxy resin other than the urethane-modified epoxy resin (step 4-1), and mixing the resulting composition with (A) modified cellulose fiber (step 4-2).

[0123] According to this manufacturing method, the resin composition of the present invention can be obtained by mixing a mixture of (B) urethane-modified epoxy resin and (C) an epoxy resin other than urethane-modified epoxy resin with (A) modified cellulose fiber.

[0124] In this production method, it is preferable to carry out a dispersion treatment during mixing in step 3 or step 4-2 from the viewpoint of further improving dispersibility. Examples of the dispersion treatment include a dispersion treatment using a grinder such as a mass colloider, or a dispersion treatment using a high-pressure homogenizer in a medium, but from the viewpoint of dispersion uniformity, a dispersion treatment using a high-pressure homogenizer is preferred. The medium is as described above for the medium. When a medium is used, it is preferable to distill off the solvent using an evaporator in order to improve the mixability in the next step.

[0125] In such a production method, the mass ratio of modified cellulose fiber / (total of component (B) and component (C)) in step 3 or step 4-2, converted into the blending amount, is preferably 0.005 or more, more preferably 0.010 or more, and even more preferably 0.030 or more, from the viewpoint of increasing the breaking elongation, while from the viewpoint of viscosity, it is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, even more preferably 0.10 or less, and even more preferably 0.07 or less.

[0126] Another preferred embodiment of the method for producing a resin composition of the present invention is a method for producing a resin composition containing (B) a urethane-modified epoxy resin and (C) an epoxy resin other than the urethane-modified epoxy resin, comprising: Step 5: mixing (A) modified cellulose fiber with (C) an epoxy resin other than the urethane-modified epoxy resin; and Step 6: mixing the composition obtained in Step 5 with (B) the urethane-modified epoxy resin.

[0127] According to this manufacturing method, the resin composition of the present invention can be obtained by mixing a mixture of (A) modified cellulose fiber and (C) an epoxy resin other than a urethane-modified epoxy resin with (B) a urethane-modified epoxy resin.

[0128] In this production method, it is preferable to carry out a dispersion treatment during mixing in step 5 from the viewpoint of further improving dispersibility. Examples of the dispersion treatment include a dispersion treatment using a grinder such as a mass colloider, or a dispersion treatment using a high-pressure homogenizer in a medium, but from the viewpoint of dispersion uniformity, a dispersion treatment using a high-pressure homogenizer is preferred. The medium is as described above. When a medium is used, it is preferable to distill off the solvent using an evaporator in order to improve the mixing properties in step 6.

[0129] In this production method, the mass ratio of modified cellulose fiber to component (C) in step 5, converted into the blending amount, is preferably 0.005 or more, more preferably 0.010 or more, and even more preferably 0.030 or more, from the viewpoint of increasing the breaking elongation, while from the viewpoint of viscosity, it is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, even more preferably 0.10 or less, and even more preferably 0.07 or less.

[0130] Among these preferred embodiments of the manufacturing method, from the viewpoint of handling and improving elongation in tensile tests and shear adhesion tests, a manufacturing method having steps 1 and 2, or a manufacturing method having step 3 or step 4 is more preferred, and a manufacturing method having steps 1 and 2 is even more preferred.

[0131] Here, the preferred blending ratio of components (A), (B), and (C) in the above-mentioned production method can be determined from the above-mentioned "amount of resin in the composition of the present invention" and "mass ratio of modified cellulose fiber / resin in the composition of the present invention."

[0132] Examples of solvents that can be used during production include the solvents that can be used in the resin composition of the present invention. When a solvent is used, the amount thereof is, for example, preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and preferably 5,000 parts by mass or less, more preferably 2,000 parts by mass or less, relative to 100 parts by mass of the resin.

[0133] <Adhesive and Adhesion Method> The adhesive of the present invention contains the resin composition of the present invention or consists of the resin composition of the present invention.

[0134] An example of the bonding method of the present invention is a method in which the adhesive of the present invention is applied to a structure (or a component thereof) and then bonded to a mating structure (or a component thereof). Examples of such adhesives include structural adhesives.

[0135] A preferred embodiment of the adhesive of the present invention is a structural adhesive. A structural adhesive is an adhesive used in structures that require mechanical strength, such as vehicles and buildings, and is preferably used to bond vehicle assemblies, replacing or reinforcing conventional joining techniques such as welding, nuts and bolts, and rivets. Therefore, there is provided a method for bonding vehicle assemblies, which includes a step of bonding the vehicle assembly using the adhesive of the present invention. The adhesive of the present invention can be used as a structural adhesive by itself, or can be used as an adhesive material to obtain an adhesive by further blending another component.

[0136] Examples of vehicles include rockets, airplanes, drones, automobiles, ships, etc. Specifically, the adhesive is used to manufacture automobile structures by structurally bonding components such as automobile bodies and automobile parts, and is particularly suitable for bonding by a method that combines spot welding and adhesives (weld bond method).

[0137] The method for applying the adhesive to the structure is not particularly limited, and examples thereof include methods using a spray, a sealer gun, a dispenser, a nozzle, a brush, a spatula, etc. Among these, it is preferable to use a dispenser because the adhesive of the present invention has excellent discharge properties. When a dispenser is used, an embodiment in which the adhesive is discharged from the dispenser and applied to the structure can be mentioned.

[0138] After laminating the structure and the other structure, the structure can be maintained at, for example, -30 to 200°C for 1 minute to 3 days to complete the adhesion between them.

[0139] The adhesive of the present invention has excellent bonding strength with a variety of materials, for example, metals such as iron, aluminum, copper, etc., alloys such as steel and aluminum alloys, plastics such as polypropylene, polyamide, polyacetal, etc., fiber-reinforced plastics such as carbon fiber-reinforced plastic and glass fiber-reinforced plastic, rubber, carbon fiber, glass, ceramics, etc., and can contribute to reducing the weight of structures such as vehicles and reducing welding costs. The adhesive of the present invention is preferably used for bonding metal members, and is more preferably used when the bonding surface of the metal member contains aluminum.

[0140] In the bonding method of the present invention, the surface of a structure or its component to which the adhesive is applied, i.e., the bonding surface, is preferably made of a material containing one or more selected from the group consisting of metal, plastic, ceramic, and glass, more preferably a material containing metal and / or plastic, and even more preferably a material containing metal. That is, the bonding method of the present invention is preferably a method in which the adhesive of the present invention is applied to a metal component and then bonded to a counterpart metal component. Note that the metal component is a material formed of metal and is different from powder, etc.

[0141] The adhesive surface material used in the adhesive method of the present invention has a linear expansion coefficient of 20×10 －６ / °C or more. Examples of such metals include aluminum and zinc. Even if the adhesive of the present invention has a high linear expansion coefficient, it is presumed that the adhesive strength is high because thermal shrinkage is suppressed.

[0142] More specifically, examples of bonding surfaces of metal members include steel sheets, SPC steel sheets, plated steel sheets (e.g., electrogalvanized steel sheets, hot-dip galvanized steel sheets, organic surface-treated steel sheets, alloyed galvanized steel sheets, zinc-nickel alloy-plated steel sheets, tin-lead plated steel sheets, and cationic electrodeposition-coated steel sheets), aluminum sheets, aluminum alloy sheets (e.g., aluminum-manganese alloy sheets, aluminum-magnesium alloy sheets), and magnesium sheets. Examples of bonding surfaces of plastics include fiber-reinforced plastic fiber sheets such as carbon fiber-reinforced plastics and glass fiber-reinforced plastics. Examples of bonding surfaces of ceramics include barium titanate, boron nitride, silicon nitride, lead zirconate titanate, aluminum oxide, aluminum nitride, silicon carbide, zinc oxide, zirconia, ferrite, indium oxide, and silicon. Examples of bonding surfaces of glass include soda-lime glass, lead glass, borosilicate glass, and quartz glass. In particular, when the bonding surface of a metal member contains aluminum, the adhesive composition and bonding method of the present invention are preferably applied.

[0143] The adhesive of the present invention is particularly excellent in adhesiveness between materials with different physical properties (for example, metal materials with different linear expansion coefficients). －６ / ℃ or higher metal and 20 × 10 －６ / °C. Specifically, the adhesive strength is also excellent for combinations of dissimilar metals (for example, steel and aluminum alloy, i.e., metals containing iron and metals containing aluminum). Metals containing iron can be used as steel plates, and metals containing aluminum can be used as alloy plates. Therefore, the adhesive method of the present specification can also be suitably applied to methods for bonding dissimilar metals.

[0144] <Method for Improving Breaking Elongation of Structural Adhesives> The breaking elongation of the adhesive can be improved by mixing the above-mentioned (A) modified cellulose fibers with the above-mentioned (B) urethane-modified epoxy resin. Therefore, the method for improving the breaking elongation of a structural adhesive of the present invention comprises the step of mixing the (A) modified cellulose fibers with the (B) urethane-modified epoxy resin.

[0145] <Adhesive Kit> The adhesive kit of the present invention comprises a container containing the adhesive of the present invention described above. The adhesive kit of the present invention is provided as a one-component adhesive or a two-component adhesive. In the case of a one-component adhesive, the adhesive of the present invention is contained in one container, and a curing agent and a curing accelerator are also contained in the same container. In the case of a two-component adhesive, an example is an adhesive kit comprising a first container containing the resin composition of the present invention and a second container containing a curing agent. Such an adhesive kit may further contain a curing accelerator. In the case of a two-component adhesive, such a kit is highly convenient because the adhesive can be cured by mixing the adhesive and the curing agent at the time of use.

[0146] The container for containing the adhesive or composition, or each of the components that make them up, is not particularly limited, and conventionally known tubes, caulking guns, glue guns, dispenser cartridges, etc. can be used.

[0147] In relation to the above-described embodiments, the present invention further discloses the following resin composition, adhesive, method for bonding vehicle assemblies, method for producing a resin composition, method for improving the breaking elongation of a structural adhesive, and adhesive kit.

[0148] <1> A resin composition comprising (A) modified cellulose fibers, (B) a urethane-modified epoxy resin, and (C) an epoxy resin other than the urethane-modified epoxy resin.

[0149] <2> The resin composition according to <1>, wherein the modified cellulose fibers have a cellulose type I crystal structure and an average fiber diameter of preferably 1 nm or more and preferably 300 nm or less. <3> The resin composition according to <1> or <2>, wherein the average fiber length of the modified cellulose fibers is preferably 10 nm or more, more preferably 30 nm or more, even more preferably 50 nm or more, and preferably 1,000 nm or less, more preferably 800 nm or less, even more preferably 500 nm or less, even more preferably 300 nm or less, and even more preferably less than 150 nm. <4> The resin composition according to any one of <1> to <3>, wherein the average aspect ratio of the modified cellulose fibers is preferably 5 or more, more preferably 10 or more, even more preferably 20 or more, and preferably 300 or less, more preferably 200 or less, even more preferably 150 or less, even more preferably 100 or less, and even more preferably 70 or less. <5> The resin composition according to any one of <1> to <4>, wherein the modified cellulose fiber is formed by bonding a modifying group to an anion-modified cellulose fiber, and the modifying group is a group containing one or more selected from the group consisting of (i) a hydrocarbon group having 3 or more carbon atoms, (ii) a silicone chain, and (iii) an alkylene oxide chain. <6> The resin composition according to any one of <1> to <5>, wherein the modifying group is bonded to an anionic group of the anion-modified cellulose fiber via an ionic bond and / or a covalent bond. <7> The resin composition according to any one of <1> to <5>, wherein the modifying group is bonded to some or all of the hydroxy groups of the cellulose fiber, or to a group (—CH ２<8> The resin composition according to any one of <1> to <7>, wherein the hydrocarbon group has preferably 3 or more carbon atoms, more preferably 8 or more, even more preferably 10 or more, and preferably 30 or less, more preferably 22 or less, and even more preferably 18 or less. <9> The resin composition according to any one of <1> to <8>, wherein the alkylene oxide chain has a formula weight (molecular weight) of preferably 500 or more, more preferably 1,000 or more, and preferably 10,000 or less, more preferably 7,000 or less. <10> The resin composition according to any one of <1> to <9> above, wherein the epoxy resin other than the urethane-modified epoxy resin is at least one selected from the group consisting of bisphenol-type epoxy resins, rubber-modified epoxy resins, alicyclic epoxy resins, glycidylamine-type epoxy resins, polysulfide-modified epoxy resins, chelate-modified epoxy resins, trisphenolmethane-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-modified epoxy resins, aliphatic epoxy resins such as epoxidized products of aliphatic polyols or derivatives thereof, polyether-modified epoxy resins, polyfunctional aromatic epoxy resins, and hydrogenated bisphenol-type epoxy resins. <11> The resin composition according to any one of <1> to <10> above, wherein the content of component (B) in the composition is preferably 1% by mass or more and less than 80% by mass, and the content of component (C) in the composition is preferably 1% by mass or more and less than 80% by mass. <12> The resin composition according to any one of <1> to <11>, wherein the content of component (B) in the composition is more preferably 5% by mass or more and 65% by mass or less, the content of component (C) is more preferably 35% by mass or more and less than 85% by mass, and even more preferably the content of component (B) is 10% by mass or more and 60% by mass or less, and the content of component (C) is 40% by mass or more and 80% by mass or less. <13> The resin composition according to any one of <1> to <12>, wherein the composition is obtained by mixing a modified cellulose fiber, a mixture with a urethane-modified epoxy resin, and an epoxy resin other than the urethane-modified epoxy resin.<14> The resin composition according to any one of <1> to <12> above, wherein the composition is obtained by mixing a mixture of a urethane-modified epoxy resin and an epoxy resin other than the urethane-modified epoxy resin, with modified cellulose fibers. <15> The resin composition according to any one of <1> to <12> above, wherein the composition is obtained by mixing a mixture of a modified cellulose fiber and an epoxy resin other than the urethane-modified epoxy resin, with a urethane-modified epoxy resin. <16> The resin composition according to any one of <1> to <15> above, wherein the ratio of the content of component (C) to the content of component (B) in the composition [(C) / (B)] is preferably 0.4 to 15, more preferably 0.5 to 12, and even more preferably 0.6 to 10. <17> The resin composition according to any one of the above items <1> to <16>, wherein the mass ratio of cellulose fiber to component (B) in the composition is preferably 0.001 or more, more preferably 0.005 or more, even more preferably 0.01 or more, and is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, even more preferably 0.10 or less. <18> The resin composition according to any one of <1> to <17>, wherein the mass ratio of cellulose fiber to resin in the composition, calculated in terms of the blending amount, is preferably 0.01 / 100 or more, more preferably 0.05 / 100 or more, even more preferably 0.1 / 100 or more, even more preferably 0.3 / 100 or more, even more preferably 0.5 / 100 or more, and is preferably 30 / 100 or less, more preferably 20 / 100 or less, even more preferably 15 / 100 or less, even more preferably 10 / 100 or less, even more preferably 7 / 100 or less, and even more preferably 5 / 100 or less. <19> The resin composition according to any one of <1> to <18>, wherein the mass ratio of the cellulose fiber to resin in the composition, calculated in terms of the blending amount, is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 30 parts by mass or more, and is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less, per 100 parts by mass of the resin.<20> The resin composition according to any one of <1> to <19> above, wherein the viscosity of the composition is preferably 1,000 mPa·s / 25°C or more, more preferably 3,000 mPa·s / 25°C or more, even more preferably 5,000 mPa·s / 25°C or more, and preferably 1,000,000 mPa·s / 25°C or less, more preferably 750,000 mPa·s / 25°C or less, even more preferably 500,000 mPa·s / 25°C or less. <21> An adhesive comprising the composition according to any one of <1> to <20> above. <22> The adhesive according to <21> above, wherein the adhesive is a structural adhesive. <23> The adhesive according to <21> or <22> above, further comprising a filler other than the modified cellulose fiber. <24> The adhesive according to any one of <21> to <23> above, wherein the adhesive is used for bonding vehicle assemblies. <25> A method for bonding vehicle assemblies, comprising the step of bonding vehicle assemblies using the adhesive according to any one of <21> to <24>. <26> A method for producing a resin composition containing a urethane-modified epoxy resin and an epoxy resin other than the urethane-modified epoxy resin, comprising: Step 1: mixing modified cellulose fibers with the urethane-modified epoxy resin, and Step 2: mixing the mixture obtained in Step 1 with an epoxy resin other than the urethane-modified epoxy resin. <27> The production method according to <26>, wherein the mass ratio of modified cellulose fibers to component (B) in Step 1, calculated in terms of blending amount, is preferably 0.005 or more, more preferably 0.010 or more, even more preferably 0.030 or more, and preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, even more preferably 0.10 or less, even more preferably 0.07 or less. <28> A method for producing a resin composition containing a urethane-modified epoxy resin and an epoxy resin other than the urethane-modified epoxy resin, the method comprising the following step 3 or step 4:<29> The mass ratio of modified cellulose fiber / (total of component (B) and component (C)) in step 3 or step 4-2 is preferably 0.005 or more, more preferably 0.010 or more, even more preferably 0.030 or more, and preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, even more preferably 0.10 or less, even more preferably 0.07 or less, in terms of the blending amount. <30> The manufacturing method according to <28>, in a manufacturing method of a resin composition containing a urethane-modified epoxy resin and an epoxy resin other than a urethane-modified epoxy resin, comprising: Step 5: mixing modified cellulose fiber with an epoxy resin other than a urethane-modified epoxy resin. Step 6: mixing the composition obtained in Step 5 with a urethane-modified epoxy resin. <31> A method for producing a resin composition according to <30> above, wherein the mass ratio of modified cellulose fiber to component (C) in Step 5, calculated in terms of blending amount, is preferably 0.005 or more, more preferably 0.010 or more, even more preferably 0.030 or more, and preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1.0 or less, even more preferably 0.5 or less, even more preferably 0.10 or less, and even more preferably 0.07 or less. <32> A method for improving the breaking elongation of a structural adhesive, comprising a step of mixing modified cellulose fiber with a urethane-modified epoxy resin. <33> An adhesive kit comprising a container containing the adhesive according to any one of <21> to <24> above. <34> An adhesive kit comprising a first container containing the composition according to any one of <21> to <24> above, and a second container containing a curing agent.

[0150] 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 scope of the present invention. Note that "normal pressure" refers to 101.3 kPa, and "normal temperature" refers to 25°C.

[0151] [Average Fiber Diameter and Average Fiber Length of Cellulose Fibers and Anion-Modified Cellulose Fibers] 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 values ​​were calculated.

[0152] [Average Fiber Diameter and Average Fiber Length of Cellulose Fibers After Micronization Treatment] 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 content of 0.0001% by mass. The dispersion was dropped onto mica and dried to prepare 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) (Digital Instruments, Nanoscope II Tapping mode AFM; Nanosensors, Point Probe (NCH) probe). 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 height. The average fiber length was calculated from the distance in the fiber direction.

[0153] [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)]

[0154] [Amount of bonded modifying groups and introduction rate of modified cellulose fibers] The amount of bonded modifying groups in modified cellulose fibers was determined by the following IR measurement method, and the amount of bonded modifying groups 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 bonded modifying groups and introduction rate 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 wave number value can be changed appropriately to calculate the bond amount and introduction rate of the modifying group. <Formula A> Bond amount of modifying group (mmol / g) = a × (b - c) ÷ b a: Carboxy group content of oxidized cellulose fiber (mmol / g) b: 1720 cm －１ c: Peak intensity of modified cellulose fiber at 1720 cm －１Equation B: Modification group introduction rate (mol%) = 100 x f / g, f: amount of modified group bonded (mmol / g), g: carboxyl group content of oxidized cellulose fiber (mmol / g).

[0155] [Content of Each Component] The content of each component other than water was calculated from the blend amount of each component. Regarding the content of glucose moieties, assuming that all of the anion-modified cellulose fiber and modifying compound blended during the preparation of the modified cellulose fiber were ionically bonded, the mass of the anion-modified cellulose fiber contained in the blended modified cellulose fiber was considered to be 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 each cellulose fiber was calculated from the difference from 100% by mass by measuring the moisture concentration in the sample using an infrared moisture meter (Shimadzu Corporation, MOC-120H). The moisture concentration was measured every 30 seconds at a constant temperature of 150°C for 1 g of sample, and the value displayed when the mass loss over 30 seconds reached 0.1% or less was used.

[0156] [Confirmation of Crystalline Structure in Modified Cellulose Fiber] The crystalline structure of the modified cellulose fiber was confirmed by measurement using an X-ray diffractometer (MiniFlex II, manufactured by Rigaku Corporation) under the following conditions. The measurement conditions were: X-ray source: Cu / Kα-radiation, tube voltage: 30 kV, tube current: 15 mA, measurement range: diffraction angle 2θ = 5 to 45°, X-ray scan speed: 10° / min. The measurement sample was a cellulose fiber to be measured, with an area of ​​320 mm. ２ The cellulose was compressed into a pellet having a thickness of 1 mm. The degree of crystallinity of the cellulose type I crystal structure was calculated from the obtained X-ray diffraction intensity according to the following formula C.

[0157] <Equation C> Cellulose I type crystallinity (%) = [(I ２２．６ -I １８．５ ) / I ２２．６ ]×100 [wherein, I ２２．６ is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6°) in X-ray diffraction, I １８．５indicates the diffraction intensity of the amorphous portion (diffraction angle 2θ=18.5°).

[0158] On the other hand, when the degree of crystallinity obtained by the above formula C is 35% or less, from the viewpoint of improving calculation accuracy, it is preferable to calculate based on the following formula D in accordance with the description on pages 199-200 of "Wood Science Experiment Manual" (edited by the Japan Wood Research Society; published in April 2000). Therefore, when the degree of crystallinity obtained by the above formula C is 35% or less, the value calculated based on the following formula D can be used as the degree of crystallinity.

[0159] <Equation D> Cellulose type I crystallinity (%) = [A ｃ / (A ｃ +A ａ )]×100 [In the formula, A ｃ is the sum of the peak areas of the lattice planes (002 plane) (diffraction angle 2θ=22.6°), (011 plane) (diffraction angle 2θ=15.1°) and (0-11 plane) (diffraction angle 2θ=16.2°) in X-ray diffraction, A ａ indicates the peak area of ​​the amorphous portion (diffraction angle 2θ=18.5°), and each peak area is determined by fitting the obtained X-ray diffraction chart with a Gaussian function.

[0160] [Cellulose fiber (equivalent amount) in modified cellulose fiber] The cellulose amount (equivalent amount) in modified cellulose fiber is the amount of cellulose in the modified cellulose fiber excluding the modifying group. In the modified cellulose fiber of the present invention, the formula weight of the modifying group may be considerably larger (for example, than the molecular weight of glucose). Therefore, in this specification, when it is appropriate to explain without considering the difference in the formula weight of the modifying group, the amount of cellulose constituting the modified cellulose fiber (equivalent amount) is expressed rather than the amount of modified cellulose fiber. The cellulose fiber (equivalent amount) in the modified cellulose fiber was measured by the following method.

[0161] (1) When one type of "modifying compound" was added, the amount of cellulose fiber (equivalent amount) was calculated using the following formula E. <Formula E> Amount of cellulose fiber (equivalent amount) (g) = Mass of modified cellulose fiber (g) / [1 + Molecular weight of modifying compound (g / mol) × Bond amount of modifying group (mmol / g) × 0.001] (2) When two or more types of "modifying compounds" were added, the amount of cellulose fiber (equivalent amount) was calculated taking into account the molar ratio of each compound (i.e., the molar ratio when the total molar amount of the added compounds is taken as 1).

[0162] Production Example 1 [Production of Anion-Modified Cellulose Fiber] Anion-modified cellulose fiber 1 having the physical properties shown in Table 1 was used as the raw material for component (A).

[0163]

[0164] Such anion-modified cellulose fiber 1 can be prepared, for example, by carrying out the following TEMPO oxidation treatment.

[0165] [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 for 30 minutes at 25°C and 100 rpm. Next, 0.26 g of 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (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 are then separated by suction filtration. The solids are dispersed in deionized water and the filtrate is separated by suction filtration. 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.

[0166] Production Example 2 [Production of Modified Cellulose Fibers 2A and 2B] 1-Methoxy-2-propanol (PGME) was added to 227 g (solid content 75 g) of the cake of anion-modified cellulose fiber 1 in Production Example 1 to obtain dispersions A (solid content concentration 2.0 mass%) and dispersion B (solid content concentration 5.0 mass%) of anion-modified cellulose fiber swollen in PGME at two different concentrations. An amine (EO / PO amine described below) was added to each of the obtained dispersions in the amounts shown in Table 2A, and the mixture was stirred at 25°C for 1 hour to obtain dispersions of modified cellulose fibers 2A and 2B having modifying groups via ionic bonds.

[0167] EO / PO amine: methoxypoly(oxyethylene / oxypropylene)-2-propylamine (JEFFAMINE M2070, manufactured by HUNTSMAN, Mw=2,000, EO:PO=31:10)

[0168]

[0169] Production Example 3 [Production of Short-Fiber Modified Cellulose Fibers 3A and 3B] Deionized water was added to 227 g (solid content 75 g) of the cake of anion-modified cellulose fiber 1 obtained in Production Example 1 until the solid content concentration changed from the value shown in Table 1 to 5% by mass. The resulting suspension was stirred at 95°C for 12 hours to obtain an aqueous suspension of short-fiber anion-modified cellulose fiber. The resulting suspension was centrifuged using a high-speed refrigerated centrifuge (Koki Holdings Co., Ltd., CR21G III) at 25°C, 10,000 G, and for 1 minute to obtain 85 g of a dispersion of short-fiber anion-modified cellulose fiber (solid content concentration 23.5% by mass) as a precipitate.

[0170] The solvent was then replaced with PGME to obtain dispersions A (solids concentration 2.0%) and B (solids concentration 5.0%) of shortened anion-modified cellulose fibers swollen in PGME. An amine (EO / PO amine as described above) was added to each of the resulting dispersions in the amounts shown in Table 2B, followed by stirring at 25°C for 1 hour to obtain dispersions of shortened modified cellulose fibers 3A and 3B having modifying groups via ionic bonds.

[0171]

[0172] Production Example 4 (Production of Short-Fiber Modified Cellulose Fiber 4) A dispersion of short-fiber, anion-modified cellulose fiber swollen in PGME (solid content concentration 5.0%) was obtained in the same manner as in Production Example 3. 0.07 g of octylamine (manufactured by Kao Corporation, Octylamine, Farmin 08D) was mixed with 21.4 g of the obtained dispersion, and the mixture was stirred at 25°C for 1 hour to obtain a dispersion of short-fiber modified cellulose fiber 4.

[0173] Production Example 5 [Production of unmodified cellulose fiber] A dispersion of shortened anion-modified cellulose fiber (solid content concentration 5.0%) swollen with PGME, the intermediate product of Production Example 3, was stirred at 25°C for 1 hour to obtain a dispersion of unmodified anion-modified cellulose fiber 5.

[0174] Production Examples 6 to 8 (Production of refined modified cellulose fibers) The dispersion of modified cellulose fiber 2A obtained in Production Example 2 was stirred at 25°C for 1 hour, and then dispersed five times at 150 MPa using a high-pressure homogenizer (Nanovaita L-ES, manufactured by Yoshida Kikai Kogyo Co., Ltd.) to obtain a dispersion of refined modified cellulose fiber 6. The modified cellulose fibers obtained in Production Examples 3 and 4 were subjected to the same dispersion treatment as above to obtain dispersions of refined modified cellulose fibers 7 and 8. The average fiber diameters and average fiber lengths of the refined modified cellulose fibers 6 to 8 and the unmodified cellulose fiber of Production Example 5 are shown in Table 2C.

[0175]

[0176] Example 1 (Production of Resin Composition) (a) Step 1: 100 g of the PGME dispersion (cellulose solids concentration 2.0%) of shortened modified cellulose fiber 3A obtained in Production Example 3 and 100 g of urethane-modified epoxy resin were stirred at 25°C for 1 hour. Next, using a high-pressure homogenizer (Yoshida Kikai Kogyo Co., Ltd., Nanovaita L-ES), this was subjected to a dispersion treatment five times at 150 MPa. The solvent was then removed using an evaporator to obtain a mixture containing modified cellulose fiber and urethane-modified epoxy resin.

[0177] Evaporator conditions: Water bath temperature: 75°C; Degree of reduced pressure (absolute pressure): 0 to 1 kPa; Judgment for completion of distillation: Judgment was made when there was a mass loss equivalent to the blended amounts of water and organic solvent.

[0178] (b) Step 2 Next, 150 g of bisphenol A type epoxy resin was added to 103 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1 model, manufactured by Primix Corporation) to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin.

[0179] (c) Step A Next, to 253 g of this mixture, 15 g of dicyandiamide (a polyaddition type curing agent, manufactured by Mitsubishi Chemical Corporation: DICY7) and 5 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (a curing accelerator, manufactured by Hodogaya Chemical Co., Ltd.: DCMU99) were added, and the mixture was stirred at 25°C for 1 hour using the same planetary mixer to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and curing agent.

[0180] (d) Step B Next, 25 g of polypropylene glycidyl ether (reactive diluent) was added to 273 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using the same planetary mixer, and then degassed under reduced pressure (1,840 Pa) for 1 hour to produce a resin composition.

[0181] Example 2 (Production of resin composition) (a) Step 1 Using the PGME dispersion of shortened modified cellulose fiber 3B (cellulose solids concentration 5.0%) obtained in Production Example 3, step 1 was carried out in the same manner as in Example 1 to obtain a mixture containing modified cellulose fiber and urethane-modified epoxy resin.

[0182] (b) Step 2 Next, 150 g of bisphenol A type epoxy resin was added to 108 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1 model, manufactured by Primix Corporation) to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin.

[0183] (c) Step A Next, to 258 g of this mixture, 15 g of dicyandiamide (a polyaddition type curing agent, manufactured by Mitsubishi Chemical Corporation: DICY7) and 5 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (a curing accelerator, manufactured by Hodogaya Chemical Co., Ltd.: DCMU99) were added, and the mixture was stirred at 25°C for 1 hour using the same planetary mixer to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and curing agent.

[0184] (d) Step B Next, 25 g of polypropylene glycidyl ether (reactive diluent) was added to 278 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using the same planetary mixer, and then degassed under reduced pressure (1,840 Pa) for 1 hour to produce a resin composition.

[0185] Example 3 (Production of Resin Composition) (a) Step 5: 100 g of the PGME dispersion (cellulose solids concentration 2.0%) of shortened modified cellulose fiber 3A obtained in Production Example 3 and 100 g of bisphenol A-type epoxy resin were stirred at 25°C for 1 hour. Next, using a high-pressure homogenizer (Yoshida Kikai Kogyo Co., Ltd., Nanovaita L-ES), this was subjected to a dispersion treatment five times at 150 MPa. The solvent was then distilled off using an evaporator to obtain a mixture containing modified cellulose fiber and bisphenol A-type epoxy resin.

[0186] (b) Step 6 Next, 67 g of urethane-modified epoxy resin was added to 103 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1 model, manufactured by Primix Corporation) to obtain a mixture containing modified cellulose fiber, epoxy resin, and urethane-modified epoxy resin.

[0187] (c) Step A Next, to 170 g of this mixture, 10 g of dicyandiamide (a polyaddition type curing agent, manufactured by Mitsubishi Chemical Corporation: DICY7) and 3 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (a curing accelerator, manufactured by Hodogaya Chemical Co., Ltd.: DCMU99) were added, and the mixture was stirred at 25°C for 1 hour using the same planetary mixer to obtain a mixture containing modified cellulose fiber, epoxy resin, urethane-modified epoxy resin, and curing agent.

[0188] (d) Step B Next, 17 g of polypropylene glycidyl ether (reactive diluent) was added to 183 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using the same planetary mixer, and then degassed under reduced pressure (1,840 Pa) for 1 hour to produce a resin composition.

[0189] Example 4 (Production of Resin Composition) (a) Step 3 100 g of the PGME dispersion (cellulose solids concentration 5.0%) of shortened modified cellulose fiber 3B obtained in Production Example 3, 60 g of bisphenol A-type epoxy resin, and 40 g of urethane-modified epoxy resin were stirred at 25°C for 1 hour. Next, using a high-pressure homogenizer (Yoshida Kikai Kogyo Co., Ltd., Nanovaita L-ES), this was subjected to a dispersion treatment five times at 150 MPa. The solvent was then distilled off using an evaporator to obtain a mixture containing modified cellulose fiber, bisphenol A-type epoxy resin, and urethane-modified epoxy resin.

[0190] (b) Step A Next, to 108 g of this mixture, 6 g of dicyandiamide (a polyaddition type curing agent, manufactured by Mitsubishi Chemical Corporation: DICY7) and 2 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (a curing accelerator, manufactured by Hodogaya Chemical Co., Ltd.: DCMU99) were added, and the mixture was stirred at 25°C for 1 hour using the same planetary mixer to obtain a mixture containing modified cellulose fiber, epoxy resin, urethane-modified epoxy resin, and curing agent.

[0191] (c) Step B Next, 10 g of polypropylene glycidyl ether (reactive diluent) was added to 116 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using the same planetary mixer, and then degassed under reduced pressure (1,840 Pa) for 1 hour to produce a resin composition.

[0192] Comparative Example 1: A resin composition similar to that of Example 1, but without modified cellulose fibers, was prepared as Comparative Example 1. Specifically, 100 g of urethane-modified epoxy resin and 150 g of bisphenol A-type epoxy resin were added and stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1, manufactured by Primix Corporation), yielding a mixture containing urethane-modified epoxy resin and epoxy resin. Next, to 250 g of this mixture, 15 g of dicyandiamide (polyaddition curing agent) and 5 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (curing accelerator, DCMU99, manufactured by Hodogaya Chemical Co., Ltd.) were added and stirred at 25°C for 1 hour using the same planetary mixer. Next, 25 g of polypropylene glycidyl ether (reactive diluent) was added to 270 g of this mixture, stirred at 25°C for 10 minutes using the same planetary mixer, and then degassed under reduced pressure (1,840 Pa) for 1 hour to produce a resin composition.

[0193] Example 5 (Production of Resin Composition) (a) Step 1 In the same manner as in step 1 of Example 1, a mixture containing modified cellulose fibers and a urethane-modified epoxy resin was obtained.

[0194] (b) Step 2 Next, a mixture containing modified cellulose fibers, a urethane-modified epoxy resin, and an epoxy resin was obtained in the same manner as in step 2 of Example 1.

[0195] (c) Step α Next, 150 g of calcium carbonate (filler) was added to 253 g of this mixture, and the mixture was stirred for 10 minutes at 25° C. using the same planetary mixer. Subsequently, 17.5 g of hydrophobic silica (filler) was added, and the mixture was further stirred for 10 minutes at 25° C. Subsequently, 10 g of calcium oxide (filler) was added, and the mixture was further stirred for 10 minutes at 25° C. to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers.

[0196] (d) Step A Next, to 430.5 g of this mixture, 15 g of dicyandiamide (a polyaddition type curing agent, manufactured by Mitsubishi Chemical Corporation: DICY7) and 5 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (a curing accelerator, manufactured by Hodogaya Chemical Co., Ltd.: DCMU99) were added, and the mixture was stirred at 25°C for 1 hour using the same planetary mixer to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, various fillers, and a curing agent.

[0197] (e) Step B Next, 25 g of polypropylene glycidyl ether (reactive diluent) was added to 450.5 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using the same planetary mixer, and then degassed under reduced pressure (1,840 Pa) for 1 hour to produce a resin composition.

[0198] Example 6 (Production of Resin Composition) (a) Step 1 A mixture containing modified cellulose fibers and a urethane-modified epoxy resin was obtained in the same manner as in step 1 of Example 2.

[0199] (b) Step 2: A mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was obtained using the same method as in Step 2 of Example 2. (c) Step α: Next, the mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was similarly blended with the various fillers blended in Step α of Example 5 to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers. (d) Step A: A mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, various fillers, and a curing agent was obtained using the same method as in Step A of Example 2. (e) Step B: A resin composition was produced using the same method as in Step B of Example 2.

[0200] Example 7 (Production of Resin Composition) (a) Step 5 In the same manner as in Step 5 of Example 3, a mixture containing modified cellulose fibers and a bisphenol A-type epoxy resin was obtained.

[0201] (b) Step 6: A mixture containing modified cellulose fiber, epoxy resin, and urethane-modified epoxy resin was obtained in the same manner as in Step 6 of Example 3. (c) Step α: Next, the mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was blended with the various fillers blended in Step α of Example 5 in the same manner to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers. (d) Step A: A mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, various fillers, and a curing agent was obtained in the same manner as in Step A of Example 3. (e) Step B: A resin composition was produced in the same manner as in Step B of Example 3.

[0202] Example 8 (Production of Resin Composition) (a) Step 3 A mixture containing modified cellulose fiber and bisphenol A-type epoxy resin was obtained in the same manner as in Step 3 of Example 4.

[0203] (b) Step 6: A mixture containing modified cellulose fiber, bisphenol A-type epoxy resin, and urethane-modified epoxy resin was obtained using the same method as in Step 6 of Example 3. (c) Step α: Next, the mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was similarly blended with the various fillers blended in Step α of Example 5 to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers. (d) Step A: A mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, various fillers, and a curing agent was obtained using the same method as in Step A of Example 4. (e) Step B: A resin composition was produced using the same method as in Step B of Example 4.

[0204] Comparative Example 2: A resin composition similar to that of Example 5, but without modified cellulose fiber, was prepared as Comparative Example 2. 100 g of urethane-modified epoxy resin and 150 g of bisphenol A-type epoxy resin were mixed and stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1, manufactured by Primix Corporation), yielding a mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin. Next, 150 g of calcium carbonate (filler) was added to 250 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using the same planetary mixer. Next, 17.5 g of hydrophobic silica (filler) was added, and the mixture was stirred for an additional 10 minutes at 25°C. Next, 10 g of calcium oxide (filler) was added, and the mixture was stirred for an additional 10 minutes at 25°C, yielding a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers.

[0205] Next, to 427.5 g of this mixture, 15 g of dicyandiamide (polyaddition type curing agent, manufactured by Mitsubishi Chemical Corporation: DICY7) and 5 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (curing accelerator, manufactured by Hodogaya Chemical Co., Ltd.: DCMU99) were added, and the mixture was stirred at 25°C for 1 hour using the same planetary mixer to obtain a mixture containing a urethane-modified epoxy resin, an epoxy resin, various fillers, and a curing agent.

[0206] Next, 25 g of polypropylene glycidyl ether (reactive diluent) was added to 447.5 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using the same planetary mixer, and then degassed under reduced pressure (1,840 Pa) for 1 hour to produce a resin composition.

[0207] Example 9 (Production of resin composition) (a) Step 1 Using the PGME dispersion of shortened modified cellulose fiber 4 (cellulose solids concentration 5.0%) obtained in Production Example 4, step 1 was carried out in the same manner as in Example 1 to obtain a mixture containing modified cellulose fiber and urethane-modified epoxy resin.

[0208] (b) Step 2 Next, 105 g of this mixture was subjected to the same procedure as in step 2 of Example 2 to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin.

[0209] (c) Step A Next, 255 g of this mixture was subjected to the same procedure as in Step A of Example 2 to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and curing agent.

[0210] (d) Step B Next, 275 g of this mixture was subjected to the same procedure as in Step B of Example 2 to produce a resin composition.

[0211] Example 10 (Production of Resin Composition) (a) Step 1: 100 g of the PGME dispersion (cellulose solids concentration 5.0%) of shortened modified cellulose fiber 3B obtained in Production Example 3 and 150 g of urethane-modified epoxy resin were stirred at 25°C for 1 hour. Next, using a high-pressure homogenizer (Yoshida Kikai Kogyo Co., Ltd., Nanovaita L-ES), this was subjected to a dispersion treatment five times at 150 MPa. The solvent was then distilled off using an evaporator to obtain a mixture containing modified cellulose fiber and urethane-modified epoxy resin.

[0212] (b) Step 2 Next, 100 g of bisphenol A type epoxy resin was added to 158 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1 model, manufactured by Primix Corporation) to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin.

[0213] (c) Step A Next, 258 g of this mixture was subjected to the same procedure as in Step A of Example 2 to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and curing agent.

[0214] (d) Step B Next, 278 g of this mixture was subjected to the same procedure as in Step B of Example 2 to produce a resin composition.

[0215] Example 11 (Production of Resin Composition) (a) Step 1: 100 g of the PGME dispersion (cellulose solids concentration 5.0%) of shortened modified cellulose fiber 3B obtained in Production Example 3 and 25 g of urethane-modified epoxy resin were stirred at 25°C for 1 hour. Next, using a high-pressure homogenizer (Yoshida Kikai Kogyo Co., Ltd., Nanovaita L-ES), this was subjected to a dispersion treatment five times at 150 MPa. The solvent was then removed using an evaporator to obtain a mixture containing modified cellulose fiber and urethane-modified epoxy resin.

[0216] (b) Step 2 Next, 225 g of bisphenol A type epoxy resin was added to 33 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1 model, manufactured by Primix Corporation) to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin.

[0217] (c) Step A Next, 258 g of this mixture was subjected to the same procedure as in Step A of Example 2 to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and curing agent.

[0218] (d) Step B Next, 278 g of this mixture was subjected to the same procedure as in Step B of Example 2 to produce a resin composition.

[0219] Example 12 (Production of resin composition) A resin composition was produced by the same procedure as in Example 2, except that a PGME dispersion of modified cellulose fiber 2B (cellulose solids concentration 5.0%) obtained in Production Example 2 was used instead of the PGME dispersion of shortened modified cellulose fiber 3B (cellulose solids concentration 5.0%) obtained in Production Example 3.

[0220] Comparative Example 3 (Production of Resin Composition) A resin composition was produced by the same procedure as in Example 2, except that the PGME dispersion of unmodified cellulose fiber from Production Example 5 was used instead of the PGME dispersion of shortened modified cellulose fiber 3B (cellulose solids concentration 5.0%) obtained in Production Example 3.

[0221] Comparative Example 4 (Production of Resin Composition) (a) Step 1: 100 g of the PGME dispersion (cellulose solids concentration 5.0%) of shortened modified cellulose fiber 3B obtained in Production Example 3 and 100 g of bisphenol A-type epoxy resin were stirred at 25°C for 1 hour. Next, using a high-pressure homogenizer (Yoshida Kikai Kogyo Co., Ltd., Nanovaita L-ES), this was subjected to a dispersion treatment five times at 150 MPa. The solvent was then distilled off using an evaporator to obtain a mixture containing modified cellulose fiber and bisphenol A-type epoxy resin.

[0222] (b) Step 2 Next, 150 g of bisphenol A type epoxy resin was added to 108 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1 model, manufactured by Primix Corporation) to obtain a mixture containing modified cellulose fiber and epoxy resin.

[0223] (c) Step A Next, 258 g of this mixture was subjected to the same procedure as in Step A of Example 2 to obtain a mixture containing modified cellulose fiber, an epoxy resin, and a curing agent.

[0224] (d) Step B Next, 278 g of this mixture was subjected to the same procedure as in Step B of Example 2 to produce a resin composition.

[0225] The compositions of the resin compositions in Examples 1 to 4, 9 to 12 and Comparative Examples 1, 3 and 4 are summarized in Table 3.

[0226]

[0227] *: The average fiber length of the modified cellulose fibers in the table is the average fiber length of the corresponding finely divided modified cellulose fibers listed in Table 2C.

[0228] Example 13 (Production of Resin Composition) (a) Step 1 A mixture containing modified cellulose fibers and a urethane-modified epoxy resin was obtained in the same manner as in step 1 of Example 9.

[0229] (b) Step 2: A mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was obtained in the same manner as in Step 2 of Example 9. (c) Step α: Next, the mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was blended with the various fillers blended in Step α of Example 5 in the same manner to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers. (d) Step A: Next, a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, various fillers, and a curing agent was obtained in the same manner as in Step A of Example 9. (e) Step B: Next, a resin composition was produced in the same manner as in Step B of Example 9.

[0230] Example 14 (Production of Resin Composition) (a) Step 1 A mixture containing modified cellulose fiber and a urethane-modified epoxy resin was obtained in the same manner as in step 1 of Example 10.

[0231] (b) Step 2: A mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was obtained in the same manner as in Step 2 of Example 10. (c) Step α: Next, the mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was blended with the various fillers blended in Step α of Example 5 in the same manner to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers. (d) Step A: Next, a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, various fillers, and a curing agent was obtained in the same manner as in Step A of Example 10. (e) Step B: Next, a resin composition was produced in the same manner as in Step B of Example 10.

[0232] Example 15 (Production of Resin Composition) (a) Step 1 In the same manner as in step 1 of Example 11, a mixture containing modified cellulose fiber and a urethane-modified epoxy resin was obtained.

[0233] (b) Step 2: A mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was obtained in the same manner as in Step 2 of Example 11. (c) Step α: Next, the mixture containing modified cellulose fiber, urethane-modified epoxy resin, and epoxy resin was blended with the various fillers blended in Step α of Example 5 in the same manner to obtain a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, and various fillers. (d) Step A: Next, a mixture containing modified cellulose fiber, urethane-modified epoxy resin, epoxy resin, various fillers, and a curing agent was obtained in the same manner as in Step A of Example 11. (e) Step B: Next, a resin composition was produced in the same manner as in Step B of Example 11.

[0234] Example 16 (Production of resin composition) A resin composition was produced by the same procedure as in Example 6, except that a PGME dispersion of modified cellulose fiber 2B (cellulose solids concentration 5.0%) obtained in Production Example 2 was used instead of the PGME dispersion of shortened modified cellulose fiber 3B (cellulose solids concentration 5.0%) obtained in Production Example 3.

[0235] Comparative Example 5 (Production of Resin Composition) A resin composition was produced by the same procedure as in Example 6, except that the PGME dispersion of unmodified cellulose fiber from Production Example 5 was used instead of the PGME dispersion of shortened modified cellulose fiber 3B (cellulose solids concentration 5.0%) obtained in Production Example 3.

[0236] Comparative Example 6 (Production of Resin Composition) (a) Step 1: 100 g of the PGME dispersion (cellulose solids concentration 5.0%) of shortened modified cellulose fiber 3B obtained in Production Example 3 and 100 g of bisphenol A epoxy resin were stirred at 25°C for 1 hour. Next, using a high-pressure homogenizer (Yoshida Kikai Kogyo Co., Ltd., Nanovaita L-ES), this was subjected to a dispersion treatment five times at 150 MPa. The solvent was then distilled off using an evaporator to obtain a mixture containing modified cellulose fiber and bisphenol A epoxy resin.

[0237] (b) Step 2 Next, 150 g of bisphenol A type epoxy resin was added to 108 g of this mixture, and the mixture was stirred at 25°C for 10 minutes using a planetary mixer (Hibismix 2P-1 model, manufactured by Primix Corporation) to obtain a mixture containing modified cellulose fiber and epoxy resin.

[0238] (c) Step α Next, the mixture containing the modified cellulose fiber and the epoxy resin was blended with the various fillers blended in step α of Example 5 in the same manner to obtain a mixture containing the modified cellulose fiber, the epoxy resin, and various fillers. (d) Step A Next, 435.5 g of this mixture was subjected to the same procedure as in step A of Example 6 to obtain a mixture containing the modified cellulose fiber, the epoxy resin, and the curing agent. (e) Step B Next, 455.5 g of this mixture was subjected to the same procedure as in step B of Example 6 to produce a resin composition.

[0239] The formulations of the resin compositions in Examples 5 to 8, 13 to 16 and Comparative Examples 2, 5 and 6 are summarized in Table 4.

[0240]

[0241] *: The average fiber length of the modified cellulose fibers in the table is the average fiber length of the corresponding finely divided modified cellulose fibers listed in Table 2C.

[0242] Details of the main components used in the above Production Examples and Examples are as follows: Urethane-modified epoxy resin (manufactured by ADEKA Corporation, urethane-modified epoxy resin, ADEKA Resin, EPU-1001, viscosity 30,000 mP·s / 25°C, epoxy equivalent 220) Bisphenol A-type epoxy resin (manufactured by Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin, jER828, viscosity 120-150 P / 25°C, epoxy equivalent 184-194; this resin is an epoxy resin other than the urethane-modified epoxy resin in the Examples, etc.) Polypropylene glycol glycidyl ether (manufactured by ADEKA Corporation, ADEKA Glycirol ED-506)

[0243] Details of the fillers used in the above examples are as follows: Calcium carbonate (heavy calcium carbonate BF200, manufactured by Bihoku Funka Kogyo Co., Ltd.) Hydrophobic silica (TS720, manufactured by Cabot Specialty Chemicals Inc.) Calcium oxide (QC-X, manufactured by Inoue Sekki Kogyo Co., Ltd.)

[0244] The compositions obtained in Examples 1 to 16 and Comparative Examples 1 to 6 were subjected to the test described in the following Test Example 1. Furthermore, the compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 4 were also subjected to the test described in the following Test Example 2.

[0245] Test Example 1 (Shear Adhesion Strength Test: Homogeneous Adhesion) In accordance with the shear strength test method described in JASO M353, the obtained resin composition was applied to a steel plate with a coating thickness of 0.15 mm, with two cold-rolled steel plates (SPCC-SD) (100 mm x 25 mm x 1.6 mm) as the adherend, i.e., the adhesive surface, overlapping each other by 12.5 mm. After removing any excess composition from the steel plate, the plate was heated and cured at 130°C for 2 hours to prepare a shear test specimen. The obtained test specimen was tested using a bench-top precision universal testing machine (Shimadzu Corporation, AGS-X) with a chuck distance of 111.5 cm, at room temperature (25°C), and at a tensile speed of 5 mm / min.

[0246] The surface treatment method of the cold-rolled steel plate SPCC-SD used here before use was in accordance with the surface treatment method for test piece materials described in JASO M353, in which the steel plate was degreased with acetone, dried, immersed in rust-preventive oil (WD-40), and then left to stand for 24 hours until the oil had been removed.

[0247] Test Example 2 (Tensile Test) The obtained resin composition was applied using an applicator to a thickness of 0.15 mm and heat-cured at 130°C for 2 hours to prepare a resin film. The obtained resin film was punched out with a dumbbell to obtain a test piece having a length of 40 mm and a width of 5 mm. The obtained test piece was subjected to a test in accordance with JIS K 7127 using a tension and compression testing machine (Shimadzu Corporation, AGS-X) with a chuck distance of 20 mm, at room temperature (25°C), and at a tensile speed of 1 mm / min, and the breaking elongation (%), maximum stress (MPa), and fracture energy (kJ / m ２The thickness of the sample was measured at three points on the test piece.

[0248] The results are shown in Tables 5 and 6.

[0249]

[0250] A comparison of compositions containing modified cellulose fibers (Examples 1 to 4) with a composition not containing modified cellulose fibers (Comparative Example 1) showed that the inclusion of modified cellulose fibers in the resin composition improved the physical properties of the cured resin, particularly the elongation. Furthermore, it was found that this effect could also be achieved by changing the type of modifying group (modifying group compound) in the modified cellulose fiber, changing the average fiber length, or changing the ratio of resin (B) to resin (C). Because the resin composition of the present invention has these effects, it was demonstrated that the resin composition of the present invention can be used as a structural adhesive.

[0251]

[0252] From the above table, it was confirmed that the compositions containing fillers (Examples 5 to 8 and Examples 13 to 16) also had the same effects as those shown in Examples 1 to 4 and Examples 9 to 12 above.

[0253] Production Example 11 (Production of Anion-Modified Cellulose Fiber 11) A resin composition similar to that of Examples 1 to 16 can be obtained by using anion-modified cellulose fiber 11 into which phosphoric acid has been introduced instead of anion-modified cellulose fiber 1 into which a carboxyl group has been introduced. Such anion-modified cellulose fiber 11 can be prepared by the following phosphorylation treatment.

[0254] [Phosphorylation Treatment] 100 parts by mass of solids of bleached coniferous kraft pulp fiber as the raw natural cellulose fiber is impregnated with a mixed aqueous solution of ammonium dihydrogen phosphate and urea, and then compressed to a concentration of 56 parts by mass of ammonium dihydrogen phosphate and 150 parts by mass of urea to obtain a chemical-impregnated fiber.

[0255] The chemical solution-impregnated fibers are dried in a dryer at 105°C to evaporate the water. The fibers from which the water has been evaporated are heated for 4 minutes in a fan dryer set at 140°C. 10,000 parts by mass of deionized water are added to 100 parts by mass of the obtained fibers, and the fibers are dispersed by stirring. The solids are then filtered off by suction filtration. 10,000 parts by mass of deionized water are added to 100 parts by mass of the solids in the filtered cake, and the fibers are dispersed by stirring. The solids are then filtered off by suction filtration.

[0256] To the resulting cake, 10,000 parts by mass of deionized water is added, and while stirring, a 1 N aqueous sodium hydroxide solution is added dropwise to obtain a slurry with a pH of 12 to 13. Next, while stirring, 0.01 M hydrochloric acid is added to the suspension to adjust the pH to 2. The solid content is then separated by suction filtration. The resulting cake is dispersed in deionized water, and the cake is separated by suction filtration. This operation is repeated until the conductivity of the filtrate reaches 200 μS / cm or less. The resulting solid content is subjected to a dehydration treatment to obtain anion-modified cellulose fibers 11.

[0257] The resin composition of the present invention can be used as a structural adhesive for vehicle assemblies and the like.

Claims

1. A resin composition comprising (A) modified cellulose fibers, (B) a urethane-modified epoxy resin, and (C) an epoxy resin other than the urethane-modified epoxy resin.

2. The composition according to claim 1, wherein (A) the modified cellulose fibers have a cellulose I crystal structure and an average fiber diameter of 1 nm or more and 300 nm or less.

3. The composition according to claim 1 or 2, wherein (A) the modified cellulose fibers are those in which a modifying group is bonded to an anion-modified cellulose fiber, and the modifying group contains at least one selected from the group consisting of (i) a hydrocarbon group having 3 or more carbon atoms, (ii) a silicone chain, and (iii) an alkylene oxide chain.

4. The composition according to claim 3, wherein the modifying group and the anionic group of the anion-modified cellulose fiber are bonded via an ionic bond and / or a covalent bond.

5. The composition according to any one of claims 1 to 4, wherein (C) the epoxy resin other than the urethane-modified epoxy resin is at least one selected from the group consisting of bisphenol type epoxy resins, rubber-modified epoxy resins, alicyclic epoxy resins, glycidylamine type epoxy resins, polysulfide-modified epoxy resins, chelate-modified epoxy resins, trisphenol methane type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene-modified epoxy resins, epoxidized products of aliphatic polyols or their derivatives, polyether-modified epoxy resins, polyfunctional aromatic epoxy resins, and hydrogenated bisphenol type epoxy resins.

6. The composition according to any one of claims 1 to 5, wherein the content of (B) the urethane-modified epoxy resin in the composition is 1% by mass or more and less than 80% by mass, and the content of (C) the epoxy resin other than the urethane-modified epoxy resin is 1% by mass or more and less than 80% by mass.

7. The composition according to any one of claims 1 to 6, obtained by mixing a mixture of (A) modified cellulose fibers and (B) a urethane-modified epoxy resin with (C) an epoxy resin other than the urethane-modified epoxy resin.

8. The composition according to any one of claims 1 to 6, obtained by mixing a mixture of (B) a urethane-modified epoxy resin and (C) an epoxy resin other than the urethane-modified epoxy resin with (A) modified cellulose fibers.

9. A composition according to any one of claims 1 to 6, obtained by mixing a mixture of (A) modified cellulose fibers and an epoxy resin other than (C) urethane-modified epoxy resin with (B) urethane-modified epoxy resin.

10. An adhesive comprising the composition according to any one of claims 1 to 9.

11. The adhesive according to claim 10, wherein the adhesive is a structural adhesive.

12. The adhesive according to claim 10 or 11, further comprising a filler other than (A) modified cellulose fibers.

13. The adhesive according to any one of claims 10 to 12, which is used for bonding vehicle assembly parts.

14. A method for bonding vehicle assembly parts, comprising a step of bonding vehicle assembly parts using the adhesive according to any one of claims 10 to 13.

15. In a method for producing a resin composition comprising (B) urethane-modified epoxy resin and an epoxy resin other than (C) urethane-modified epoxy resin, Step 1: a step of mixing (A) modified cellulose fibers and (B) urethane-modified epoxy resin, and Step 2: a step of mixing the mixture obtained in Step 1 with an epoxy resin other than (C) urethane-modified epoxy resin. A method for producing a resin composition.

16. In a method for producing a resin composition comprising (B) urethane-modified epoxy resin and an epoxy resin other than (C) urethane-modified epoxy resin, a production method having the following Step 3 or Step 4. Step 3: a step of mixing (A) modified cellulose fibers, (B) urethane-modified epoxy resin, and an epoxy resin other than (C) urethane-modified epoxy resin. Step 4: a step of mixing (B) urethane-modified epoxy resin and an epoxy resin other than (C) urethane-modified epoxy resin (Step 4-1), and mixing the resulting composition with (A) modified cellulose fibers (Step 4-2).

17. In a method for producing a resin composition comprising (B) urethane-modified epoxy resin and an epoxy resin other than (C) urethane-modified epoxy resin, Step 5: a step of mixing (A) modified cellulose fibers and an epoxy resin other than (C) urethane-modified epoxy resin. Step 6: a step of mixing the composition obtained in Step 5 with (B) urethane-modified epoxy resin. A method for producing a resin composition.

18. A method for improving the elongation at break of a structural adhesive, comprising a step of mixing (A) modified cellulose fibers and (B) urethane-modified epoxy resin.

19. An adhesive kit comprising a container containing the adhesive according to any one of claims 10 to 13.

20. An adhesive kit comprising a first container containing the composition according to any one of claims 1 to 9 and a second container containing a curing agent.

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