JP2018044097A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition using a cellulose nanofiber, and having high heat resistance and adhesive strength.SOLUTION: An adhesive composition contains a fine fibrous cellulose satisfying the following conditions (A)-(E) and a matrix resin: (A) the fine fibrous cellulose has a number average fiber diameter of 2-500 nm, (B) it has an average aspect ratio of 10-1000, (C) it has a cellulose I crystal structure, (D) it has an anionic functional group, (E) a polyether amine represented by formula (1) binds to part or all of the anionic functional group described in (D).SELECTED DRAWING: None

Description

  The present invention relates to an adhesive composition.

  In recent years, due to increasing social interest in the environment and safety, there is an increasing need for products that save energy and reduce carbon dioxide. Particularly in the field of transportation equipment such as automobiles and aircraft, attempts have been made to reduce the weight of the vehicle body in order to improve fuel efficiency. It is necessary to keep the rigidity high while reducing the weight of the vehicle body by using aluminum, carbon fiber composite material, or the like from a conventional steel plate. In order to reduce the weight, it is necessary to use various light-weighted substrates in combination, and it is necessary to increase the strength and rigidity of the joint, that is, to maintain the strength of the adhesive joint. In an automobile, in order to keep the rigidity and strength of the vehicle body high, the adhesive used is required to have high adhesion to a steel plate even at high temperatures. For example, Patent Document 1 proposes using a resin composition containing cellulose nanofibers as an adhesive.

JP 2016-138220 A

  Since the cellulose nanofiber described in Patent Document 1 is mechanically defibrated from hydrophilic cellulose and is not oleophilic, the cellulose nanofibers aggregate in the resin. Therefore, the heat resistance of the resin cannot be improved as expected. An object of the present invention is to provide an adhesive composition having heat resistance and high adhesiveness by making cellulose fibers oleophilic to uniformly disperse fine fibrous cellulose in a resin.

The present inventors have solved the above problems with an adhesive composition containing fine fibrous cellulose and a matrix resin.
That is, an object of the present invention is to provide the following [1] to [6].
[1] An adhesive composition comprising fine fibrous cellulose and a matrix resin that satisfy the following conditions (A) to (E).
(A) Number average fiber diameter of 2 nm to 500 nm (B) Average aspect ratio of 10 to 1000 (C) Cellulose type I crystal structure (D) Anionic functional group (E) (D) A polyetheramine represented by the following formula (1) is bonded to a part or all of the anionic functional group.

〔上記式（１）中、Ｒ^１、Ｒ^２、Ｒ^３は炭素数１以上２０以下の直鎖もしくは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ｎ1、ｎ2、ｎ3はそれぞれ０以上８０以下を示し、（ｎ1＋ｎ2＋ｎ3）は１０以上２４０以下を示し、ＡＯは炭素数２以上４以下のオキシアルキレン基を示し、xの平均値は０．５以上１以下、ｙ、ｚの平均値は０以上１以下を示す。〕
[２]上記微細繊維状セルロースがさらに下記条件を満たすことを特徴とする[１]に記載の接着剤組成物。
（F）（D）記載のアニオン性官能基の一部、または全てに上記一般式（１）で示すポリエーテルアミンと下記一般式（２）で示すアミン化合物が結合している。

[In the above formula (1), R ¹ , R ² and R ³ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and n1, n2 and n3 each represent 0 or more and 80 or less, (n1 + n2 + n3) represents 10 or more and 240 or less, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and the average value of x is 0.5 or more and 1 or less. The average value of y and z is 0 or more and 1 or less. ]
[2] The adhesive composition according to [1], wherein the fine fibrous cellulose further satisfies the following conditions.
(F) A polyether amine represented by the general formula (1) and an amine compound represented by the following general formula (2) are bonded to a part or all of the anionic functional groups described in (D).

〔上記式（２）中、Ｒ^４、Ｒ^５、Ｒ^６は炭素数１以上２０以下の直鎖あるいは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示す。〕
[３]上記微細繊維状セルロースのアニオン性官能基がカルボキシル基であることを特徴とする[１]または[２]記載の接着剤組成物。
[４]上記マトリクス樹脂が、重縮合系樹脂、重付加重合系樹脂、付加縮合系樹脂、および付加重合系樹脂から選択される、１種又は２種以上であることを特徴とする[１]ないし[３]のいずれか１に記載の接着剤組成物。
[５]上記マトリクス樹脂が、エポキシ樹脂、ウレタン樹脂、アクリル系樹脂、酸ビニル系樹脂、および炭化水素系樹脂を含有することを特徴とする請求項[１]ないし[４]のいずれか１項に記載の接着剤組成物。
[６]上記微細繊維状セルロースの固形分含有量が０．０５質量％以上３．０質量％以下の範囲であることを特徴とする［１］ないし［５］のいずれか一に記載の接着剤組成物。

[In the above formula (2), R ⁴ , R ⁵ and R ⁶ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom. ]
[3] The adhesive composition according to [1] or [2], wherein the anionic functional group of the fine fibrous cellulose is a carboxyl group.
[4] The matrix resin is one or more selected from polycondensation resins, polyaddition polymerization resins, addition condensation resins, and addition polymerization resins. [1] Or the adhesive composition according to any one of [3].
[5] The matrix resin according to any one of [1] to [4], wherein the matrix resin contains an epoxy resin, a urethane resin, an acrylic resin, an acid vinyl resin, and a hydrocarbon resin. The adhesive composition described in 1.
[6] The adhesion according to any one of [1] to [5], wherein the solid content of the fine fibrous cellulose is in the range of 0.05% by mass to 3.0% by mass. Agent composition.

  The adhesive composition of the present invention has heat resistance and high adhesive strength.

  The adhesive composition of the present invention contains a predetermined fine fibrous cellulose and a resin.

[Fine fibrous cellulose]
The fine fibrous cellulose satisfies the following conditions.

<Average fiber diameter>
The number average fiber diameter of the fine fibrous cellulose is 2 nm or more and 500 nm or less, preferably 2 nm or more and 150 nm or less, more preferably 2 nm or more and 100 nm or less, and particularly preferably 3 nm or more and 80 nm or less. If the number average fiber diameter is less than 2 nm, the crystalline structure of the fine fibrous cellulose may be lost, and the adhesive strength may not be improved. Even when the number average fiber diameter exceeds 500 nm, the fine fibrous cellulose is an adhesive. There is a risk of sedimentation in the composition. The maximum fiber diameter is preferably 1000 nm or less, particularly preferably 500 nm or less, from the viewpoint of dispersibility of the fine fibrous cellulose.

  The number average fiber diameter and the maximum fiber diameter of the fine fibrous cellulose can be measured, for example, as follows. That is, an aqueous dispersion of fine cellulose having a solid content of 0.05 to 0.1% by weight was prepared, and the dispersion was cast on a carbon film-coated grid that had been subjected to a hydrophilization treatment. (TEM) observation sample. In addition, when the fiber of a big fiber diameter is included, you may observe the scanning electron microscope (SEM) image of the surface cast on glass. Then, observation with an electron microscope image is performed at a magnification of 5000 times, 10000 times, or 50000 times depending on the size of the constituent fibers. At that time, an axis having an arbitrary vertical and horizontal image width is assumed in the obtained image, and the sample and observation conditions (magnification, etc.) are adjusted so that 20 or more fibers intersect the axis. Then, after obtaining an observation image that satisfies this condition, two random axes, vertical and horizontal, per image are drawn on this image, and the fiber diameter of the fiber that intersects the axis is visually read. In this way, images of at least three non-overlapping surface portions are taken with an electron microscope, and the fiber diameter values of the fibers intersecting with each of the two axes are read (thus, at least 20 × 2 × 3 = 120). Information on the fiber diameter of the book is obtained). The maximum fiber diameter and the number average fiber diameter are calculated from the fiber diameter data thus obtained.

<Average aspect ratio>
The average aspect ratio of the fine fibrous cellulose is 10 or more and 1000 or less, preferably 100 or more, more preferably 200 or more. When the average aspect ratio is less than 10, the surface charge is reduced, and the fine fibrous cellulose may aggregate in the adhesive composition.

  The average aspect ratio of the fine fibrous cellulose can be measured, for example, by the following method, that is, according to the method described above, the number average fiber diameter and the fiber length are calculated, and the average is calculated using these values. The aspect ratio was calculated according to the following formula.

<Cellulose I-type crystal structure>
The fine fibrous cellulose is a fiber obtained by refining a naturally-derived cellulose raw material having an I-type crystal structure. That is, in the process of biosynthesis of natural cellulose, nanofibers called microfibrils are first formed almost without exception, and these form a multi-bundle to form a higher order solid structure.
The cellulose constituting the fine fibrous cellulose has an I-type crystal structure, for example, in the diffraction profile obtained by wide-angle X-ray diffraction image measurement, in the vicinity of 2 theta = 14-17 ° and 2 theta = 22-23. It can be identified from the fact that there are typical peaks at two positions near °.

<Anionic functional group>
The fine fibrous cellulose has an anionic functional group.

  Although it does not restrict | limit especially as an anionic functional group of this invention, Specifically, a carboxyl group, a phosphoric acid group, and a sulfuric acid group are mentioned, Among these, the reason of the ease of introduction | transduction of an anionic functional group to a cellulose is mentioned. To carboxyl group.

  As a method of introducing a carboxyl group into cellulose, a method of reacting at least one selected from the group consisting of a compound having a carboxyl group at the hydroxyl group of cellulose, an acid anhydride of a compound having a carboxyl group, and derivatives thereof, A method of converting a hydroxyl group into a carboxy group by oxidizing the hydroxyl group can be mentioned.

  Although it does not specifically limit as a compound which has the said carboxyl group, Specifically, a halogenated acetic acid is mentioned, As a halogenated acetic acid, chloroacetic acid, bromoacetic acid, iodoacetic acid etc. are mentioned.

  The acid anhydride of the compound having a carboxyl group is not particularly limited, but acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, itaconic anhydride, and the like. Can be mentioned.

  Although it does not specifically limit as a derivative | guide_body of the compound which has the said carboxyl group, The derivative of the acid anhydride of the compound which has a carboxyl group and the acid anhydride imidation of a compound which has a carboxyl group is mentioned.

  Although it does not specifically limit as an acid anhydride imidation thing of a compound which has a carboxyl group, Imidation thing of dicarboxylic acid compounds, such as maleimide, succinic acid imide, and phthalic acid imide, is mentioned.

  The acid anhydride derivative of the compound having a carboxyl group is not particularly limited, but at least one of the acid anhydrides of the compound having a carboxyl group, such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride and the like. And those in which a part of the hydrogen atoms are substituted with a substituent (for example, an alkyl group, a phenyl group, etc.).

  The method for oxidizing the hydroxyl group of the cellulose is not particularly limited, and specifically, a method in which an N-oxyl compound is used as an oxidation catalyst and a cooxidant is allowed to act.

  In the present invention, as a method for introducing a carboxyl group into cellulose, a method of oxidizing the hydroxyl group of cellulose is preferable because of excellent hydroxyl group selectivity on the fiber surface and mild reaction conditions. Hereinafter, cellulose having a carboxyl group introduced by oxidation of a hydroxyl group is referred to as oxidized cellulose.

  Moreover, the following method is mentioned as a method of introduce | transducing a phosphate group into a cellulose as one Embodiment. That is, a method of mixing phosphoric acid or phosphoric acid derivative powder or aqueous solution into a dried or wet cellulose fiber raw material, a method of adding an aqueous solution of phosphoric acid or phosphoric acid derivative to a dispersion of cellulose fiber raw material, etc. It is done. In these methods, dehydration treatment, heat treatment, and the like are usually performed after mixing or adding a powder or aqueous solution of phosphoric acid or phosphoric acid derivative. Here, examples of phosphoric acid or phosphoric acid derivatives include at least one compound selected from oxo acids, polyoxo acids or derivatives thereof containing a phosphorus atom. Thereby, the compound or salt thereof containing a phosphate group at the hydroxyl group of the glucose unit constituting cellulose undergoes a dehydration reaction to form a phosphate ester, and the phosphate group or salt thereof is introduced.

  The anionic functional group content of the fine fibrous cellulose of the present invention is preferably in the range of 0.5 mmol / g to 2.5 mmol / g, more preferably 1.5 mmol / g from the viewpoint of dispersion stability of the fine fibrous cellulose. The range is from g to 2.0 mmol / g.

  The amount of the anionic functional group of the fine fibrous cellulose is measured by the following method, for example, when the anionic functional group is a carboxyl group. That is, 60 ml of a 0.5 to 1% by weight slurry was prepared from a cellulose sample precisely weighed in dry weight, adjusted to pH 2.5 with 0.1 M hydrochloric acid aqueous solution, and then 0.05 M sodium hydroxide aqueous solution was added. Drop and measure the electrical conductivity. The measurement is continued until the pH is about 11. The amount of carboxyl groups can be determined from the amount of sodium hydroxide consumed in the neutralization step of the weak acid with a gentle change in electrical conductivity (V) according to the following formula (2).

  The amount of the anionic functional group of the fine fibrous cellulose is measured by the following method, for example, when the anionic functional group is a carboxymethyl group. That is, the above-mentioned fine fibrous cellulose is prepared in a 0.6% by mass slurry, and 0.1M hydrochloric acid aqueous solution is added to adjust the pH to 2.4, and then 0.05N sodium hydroxide aqueous solution is dropped to adjust the pH to 11. The electrical conductivity is measured until the amount of carboxyl groups is measured from the amount of sodium hydroxide consumed in the neutralization step of the weak acid where the change in electrical conductivity is slow, and can be calculated using the following equation.

<Polyetheramine>
The fine fibrous cellulose is formed by bonding polyetheramine. Cellulose fibers are surface-modified with polyetheramine to stabilize the dispersion in a matrix resin and a solvent.

In the above formula (1), R ¹ , R ² and R ³ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and n1, n2 , N3 each represents 0 or more and 80 or less, (n1 + n2 + n3) represents 10 or more and 240 or less, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and the average value of x is 0.5 or more and 1 or less, y , Z represents 0 or more and 1 or less. R ¹ , R ² and R ³ are preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. AO is preferably an oxyalkylene group having 2 carbon atoms, n1, n2, and n3 are each preferably 20 or more and 80 or less, and (n1 + n2 + n3) is preferably 20 or more and 160 or less, more preferably 20 or more and 80 or less. preferable. The average value of x is preferably 0.8 to 1, and the average value of y and z is preferably 0 to 0.2.

  Examples of the polyetheramine that can be suitably used in the present invention include the following formula (i):

〔式中、Ｒ^ａは炭素数１以上２０以下の直鎖もしくは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ＥＯ及びＰＯはランダム又はブロック状に存在し、ａはＥＯの平均付加モル数を示す正の数、ｂはＰＯの平均付加モル数を示す正の数であり、ａ、ｂはそれぞれ０以上８０以下が好ましく、ａ＋ｂは１０以上８０以下であり、好ましくは２０以上８０以下である〕があげられる。

[Wherein, R ^a represents a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and EO and PO are present in a random or block form, a is a positive number indicating the average added mole number of EO, b is a positive number indicating the average added mole number of PO, a and b are each preferably 0 or more and 80 or less, and a + b is 10 or more and 80 or less. , Preferably 20 or more and 80 or less].

  Examples of polyetheramines that can be suitably used in commercial products include, for example, Jeffamine M-2070, Jeffamine M-2005, Jeffamine M-1000, Jeffamine M-2095, Jeffamine M-3085, XTJ-436, manufactured by HUNTSMAN. Examples thereof include Polyetheramine D 2000 manufactured by the Company.

  Examples of the polyetheramine that can be suitably used in the present invention include the following formula (ii):

〔式中、Ｒ^ｂ、Ｒ^ｃは炭素数１以上２０以下の直鎖または分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ＥＯ及びＰＯはランダム又はブロック状に存在し、ｃおよびｅはＥＯの平均付加モル数を示し、ｄおよびｆはＰＯの平均付加モル数を示し、ｃ、ｄ、ｅ、ｆはそれぞれ０以上８０以下であり、ｃ＋ｄおよびｅ＋ｆは１０以上１６０以下であり、好ましくは２０以上８０以下である〕
下記式（iii）

[Wherein, R ^b and R ^c represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and EO and PO are randomly or block-like. Present, c and e represent the average number of moles added of EO, d and f represent the average number of moles added of PO, c, d, e and f are each from 0 to 80 and c + d and e + f are 10 Or more and 160 or less, preferably 20 or more and 80 or less]
Formula (iii) below

〔式中、Ｒ^ｄ、Ｒ^ｅ、Ｒ^ｆは炭素数１以上２０以下の直鎖あるいは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ＥＯ及びＰＯはランダム又はブロック状に存在し、ｇ、ｉおよびｋはＥＯの平均付加モル数を示し、ｈ、ｊおよびｌはＰＯの平均付加モル数を示し、ｇ、ｈ、ｉ、ｊ、ｋ、およびｌはそれぞれ０以上８０以下であり、ｇ＋ｈ、ｉ＋ｊ、およびｋ＋ｌはそれぞれ１０以上２４０以下であり、好ましくは２０以上１６０以下であり、より好ましくは２０以上８０以下である〕で表される化合物があげられる。

[Wherein R ^d , R ^e and R ^f represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and EO and PO are random or Present in block form, g, i and k represent the average added moles of EO, h, j and l represent the average added moles of PO, g, h, i, j, k and l are respectively 0 to 80, and g + h, i + j, and k + 1 are each from 10 to 240, preferably from 20 to 160, and more preferably from 20 to 80.

  The said fine fibrous cellulose of this invention may have only 1 type of the said polyether amine, and may have 2 or more types.

<Amine compound>
Moreover, when a part of anionic group of a fine fibrous cellulose couple | bonds with polyether amine, you may couple | bond the amine compound shown by following General formula (2) with the remaining anionic group.

In the above formula (2) ^shows the R ^4, R 5, ^{R 6} is linear or branched alkylene group having 1 to 20 carbon atoms, having 1 to 20 arylene group having a carbon or a hydrogen atom.

R ⁴ , R ⁵ and R ⁶ are preferably an alkyl group having 2 to 18 carbon atoms, and more preferably an alkyl group having 2 to 8 carbon atoms.

  The amine compound represented by the formula (2) is not particularly limited, and examples thereof include propylamine, butylamine, hexylamine, cyclohexylamine, octylamine, decylamine, hexadecylamine, octadecylamine, ethanolamine, and benzylamine. Secondary amines such as primary amine, dimethylamine, diethylamine, diisopropylamine, diallylamine, dioctadecylamine, methylethylamine, tertiary butylethylamine, diethanolamine, dibenzylamine, triethylamine, triisopropylamine, tributylamine, trioctyl Amine, dimethylbutylamine, dimethyloctylamine, dimethyldecylamine, dimethyloctadecylamine, dimethylbenzylamine, diethyl Methylamine, dioctadecyl methylamine, triethanolamine, triisopropanolamine, lauryl diethanolamine, tertiary amines such as tribenzylamine, and the like. Among these, propylamine, butylamine, hexylamine, octylamine, decylamine, hexadecylamine, octadecylamine, ethanolamine, dimethylamine, diethylamine, diisopropylamine, diallylamine, dioctadecylamine, methylethylamine, tertiary butylethylamine, diethanolamine , Triethylamine, triisopropylamine, tributylamine, trioctylamine, dimethylbutylamine, dimethyloctylamine, dimethyldecylamine, dimethyloctadecylamine, dimethylbenzylamine, diethylmethylamine, dioctadecylmethylamine, triethanolamine, triisopropanolamine, Lauryl diethanolamine is preferred, triethylamine, Li isopropylamine, tributylamine, trioctylamine, dimethyl butyl amine, dimethyl octylamine, dimethyl decylamine, dimethyl octadecylamine, dimethyl benzylamine, diethyl methyl amine, dioctadecyl methylamine being more preferred.

  When the polyether amine and the amine compound are used in combination, the blending ratio in terms of the dispersibility of the fine fibrous cellulose and the adhesive strength of the adhesive composition is a polyether amine / amine compound = 99/1 to 25/75 in terms of molar ratio. Is preferable, and 50/50 to 25/75 is more preferable.

[Production method of fine fibrous cellulose]
The fine fibrous cellulose of the present invention is preferable because it can be more efficiently produced by the production method having the following steps (1) to (4).
Step (1): Dispersing cellulose fibers having a cellulose I-type crystal structure in water, and then converting the hydroxyl groups of the cellulose fibers to substituents having a carboxyl group (2): Dispersion medium for the cellulose fibers Step (3) of substituting water with an organic solvent: Step of adding polyetheramine to the cellulose fiber after substitution of the dispersion medium (4): Cellulose fibers bonded with the polyetheramine in the organic solvent Nano-defibration process

<Step (1)>
Step (1) is a step of converting the hydroxyl group of cellulose having a cellulose I-type crystal structure into a substituent having a carboxyl group (carboxyl group, carboxyl base, carboxylalkyl group, etc.) by oxidation or the like.

  As the cellulose having a cellulose I-type crystal structure, natural cellulose is usually used. Here, natural cellulose means purified cellulose isolated from a biosynthetic system of cellulose such as plants, animals, and bacteria-producing gels. More specifically, softwood pulp, hardwood pulp, cotton pulp such as cotton linter and cotton lint, non-wood pulp such as straw pulp and bagasse pulp, bacterial cellulose (BC), cellulose isolated from sea squirt, seaweed Cellulose isolated from Among these, softwood pulp, hardwood pulp, cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as straw pulp and bagasse pulp are preferable. The natural cellulose is preferably subjected to a treatment for increasing the surface area such as beating, because the reaction efficiency can be increased and the productivity can be increased.

  The fact that cellulose has the I-type crystal structure is typical in two positions of 2 theta = 14 to 17 ° and 2 theta = 22 to 23 ° in a diffraction profile obtained by wide-angle X-ray diffraction image measurement. It can be identified from having a typical peak.

  Examples of the cellulose in which the hydroxyl group on the surface of the cellulose fiber is converted to a substituent having a carboxyl group include oxidized cellulose, carboxymethyl cellulose, polyvalent carboxymethyl cellulose, or a salt thereof. Of these, oxidized cellulose using an N-oxyl compound as an oxidizing agent, which is excellent in the selectivity of hydroxyl groups on the fiber surface and has mild reaction conditions, is preferable.

  As described above, a method for obtaining oxidized cellulose using an N-oxyl compound that can be more suitably selected from among the fine fibrous cellulose having a carboxyl group of the present invention as an oxidizing agent will be described in detail below.

(Oxidation process)
The oxidized cellulose is oxidized in the presence of the natural cellulose, the N-oxyl compound, and a co-oxidant to obtain a cellulose fiber containing a carboxy group.

  The dispersion medium of cellulose in the oxidation reaction is water, and the concentration of cellulose in the reaction aqueous solution is arbitrary as long as the cellulose can be sufficiently diffused. Usually, it is about 5% or less based on the weight of the reaction aqueous solution, but the reaction concentration can be increased by using a device having a strong mechanical stirring force.

  As said N-oxyl compound, the compound which has a nitroxy radical generally used as an oxidation catalyst is mention | raise | lifted, for example. The N-oxyl compound is preferably a water-soluble compound, more preferably a piperidine nitroxyoxy radical, particularly a 2,2,6,6-tetramethylpiperidinooxy radical, or 4-acetamido-2,2, 6,6-tetramethylpiperidinooxy radical is preferred. The N-oxyl compound is added in a catalytic amount, preferably 0.1 to 4 mmol / l, more preferably 0.2 to 2 mmol / l.

  The co-oxidant is not a substance that directly oxidizes a hydroxyl group of cellulose, but a substance that oxidizes an N-oxyl compound used as an oxidation catalyst. Examples thereof include hypohalous acid or a salt thereof, halous acid or a salt thereof, perhalogenic acid or a salt thereof, hydrogen peroxide, a perorganic acid, and the like. These may be used alone or in combination of two or more. Of these, alkali metal hypohalites such as sodium hypochlorite and sodium hypobromite are preferable. And when using the said sodium hypochlorite, it is preferable in terms of reaction rate to advance reaction in presence of alkali bromide metals, such as sodium bromide. The addition amount of the alkali metal bromide is about 1 to 40 times mol, preferably about 10 to 20 times mol for the N-oxyl compound.

  The pH of the aqueous reaction solution is preferably maintained in the range of about 8-11. The temperature of the aqueous solution is arbitrary at about 4 to 40 ° C., but the reaction can be performed at room temperature (25 ° C.), and the temperature is not particularly required to be controlled.

  In order to obtain the target amount of carboxyl groups and the like, the degree of oxidation is controlled by the amount of co-oxidant added and the reaction time.

(Reduction treatment process)
The cellulose fiber after the oxidation treatment is preferably reduced with a reducing agent. As a result, part or all of the aldehyde group and the ketone group are reduced to return to the hydroxyl group. Note that the carboxyl group is not reduced. The total content of carbonyl groups (aldehyde group and ketone group) calculated by the semicarbazide method described later of the oxidized cellulose by the reduction is preferably 0.3 mmol / g or less, particularly preferably 0.8. 1 mmol / g or less. Thereby, the molecular weight fall of fine fibrous cellulose is suppressed and the thickening effect in a solvent can be maintained for a long time. In addition, when a carbonyl group exceeds 0.5 mmol / g, there exists a possibility that generation | occurrence | production of the aggregate by long-term storage and a viscosity may fall remarkably with time passage. As the reducing agent used in the reduction reaction, it is possible to use a common one, _{preferably, LiBH 4, NaBH 3 CN,} NaBH 4 and the like. Among these, NaBH ₄ is particularly preferable from the viewpoint of cost and availability.

  The amount of the reducing agent in the cellulose converted into a substituent having a carboxyl group is preferably in the range of 0.1 to 20% by weight, particularly preferably in the range of 3 to 10% by weight, based on the standard. The reaction is carried out at room temperature or slightly higher than room temperature for 10 minutes to 10 hours, preferably 30 minutes to 2 hours.

  The total content of carbonyl groups (aldehyde group and ketone group) by the semicarbazide method is measured as follows, for example. That is, first, 50 ml of a semicarbazide hydrochloride 3 g / l aqueous solution adjusted to pH = 5 with a phosphate buffer is added to a dried sample, sealed, and shaken for 2 days. Next, 10 ml of this solution is accurately collected in a 100 ml beaker, 25 ml of 5N sulfuric acid and 5 ml of 0.05N potassium iodate aqueous solution are added and stirred for 10 minutes. Thereafter, 10 ml of a 5% potassium iodide aqueous solution was added, and immediately titrated with a 0.1N sodium thiosulfate solution using an automatic titrator. From the titration amount and the like, the amount of carbonyl groups in the sample was determined according to the following formula. Can be requested. Semicarbazide reacts with an aldehyde group or a ketone group to form a Schiff base (imine), but does not react with a carboxyl group. Therefore, it is considered that only the carbonyl group amount can be quantified by the above measurement.

<Step (2)>
In the step (2), the cellulose fiber after the treatment is washed with an acid so that the carboxyl group introduced in the step (1) is converted into an acid form, and is appropriately purified by repeated filtration and washing with a centrifugal separator. In this step, after the solid-liquid separation is performed, etc., the cellulose is repeatedly washed with an organic solvent to replace the water with the organic solvent.

(acid)
The acid is not particularly limited as long as the aqueous cellulose fiber dispersion can be maintained acidic, and there are no particular limitations on the type of acid. Inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, acetic acid, and hydrogen peroxide, citric acid, malic acid Any of organic acids such as lactic acid, adipic acid, sebacic acid, sodium sebacate, stearic acid, maleic acid, succinic acid, tartaric acid, fumaric acid and gluconic acid can be used. Hydrochloric acid is preferably used from the standpoints of avoiding deterioration and damage of cellulose fibers due to acid and facilitating waste liquid treatment.

(Organic solvent)
The organic solvent is not particularly limited. For example, methanol, ethanol, isopropyl alcohol, 2-butanol, 1-pentanol, octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, stearyl alcohol, glycerin, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, Propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, alcohols such as 2-methyl-1-propanol glycerol, acetic acid, propionic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, stearin, olein Carboxylic acids such as acid, linolenic acid, lactic acid, benzoic acid, succinic acid, maleic acid, fumaric acid, hexane, Hydrocarbons such as heptane, octane, decane, liquid paraffin, aromatic hydrocarbons such as toluene, xylene, ethylbenzene, naphthalene, amides such as dimethyl sulfoxide, dimethylformamide, dimethylacetamide, acetanilide, acetone, methyl ethyl ketone, diethyl ketone , Ketones such as methyl isobutyl ketone, cyclohexanone, benzophenone, halogens such as methylene chloride, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl acetate, acetic acid Ethyl, propyl acetate, butyl acetate, methyl butyrate, di-2-ethylhexyl adipate, diisononyl adipate, adipic acid Diisodecyl, di-2-ethylhexyl sebacate, di-2-ethylhexyl azelate, 4-cyclohexene-1,2-dicarboxylate bis (2-ethylhexyl), tricresyl phosphate, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxy Esters such as ethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyethylene glycol, polytetramethylene oxide, polyethers such as polyoxyethylene alkyl ether, silicone oils such as polydimethylsiloxane, dimethyl sulfoxide, Acetonitrile, propionitrile, ester oil, light oil, kerosene, crude oil, salad oil, soybean oil, castor oil, triglyceride, polyisoprene, fluorine-modified oil, etc. That. These may be used alone or in combination of two or more. Moreover, the matrix resin mentioned later, the solution which diluted the matrix resin with the organic solvent, or the monomer of a matrix resin can also be used instead of an organic solvent.

<Step (3)>
Step (3) is a step of adding the polyetheramine represented by the above formula (1) to the oxidized cellulose after the dispersion medium substitution. Thereby, the polyether amine shown by the said Formula (1) couple | bonds with the carboxyl group of the said oxidized cellulose, and the lipophilicity of a cellulose is performed. In addition, the said reaction is performed in the said organic solvent.

<Process (4)>
Step (4) is a step of nano-defining the oleophilic cellulose fiber in an organic solvent. Examples of the disperser used for the nano-defibration include, for example, a homomixer under high-speed rotation, a high-pressure homogenizer, an ultra-high pressure homogenizer, an ultrasonic dispersion treatment, a beater, a disc type refiner, a conical type refiner, a double disc type refiner, and a grinder. By using a powerful and beating ability apparatus such as the above, it becomes possible to further miniaturize, and more efficient and advanced downsizing becomes possible. As the disperser, for example, a screw mixer, a paddle mixer, a disper mixer, a turbine mixer, or the like may be used.

[Matrix resin]
The matrix resin that can be suitably used in the present invention is not particularly limited as long as it can be used as an adhesive, and may be a monomer, an oligomer, or a polymer, and the polymer is a homopolymer. Or a copolymer. These may be used alone or in combination.

  The matrix resin is not particularly limited, and examples thereof include polycondensation resins, polyaddition polymerization resins, addition condensation resins, and addition polymerization resins. Of these, heavy resins are used from the viewpoint of compatibility with fine fibrous cellulose. Addition polymerization resins and addition polymerization resins are preferred.

  Examples of the polyaddition polymerization resin include urethane resin, epoxy resin, aldehyde resin, and ketone resin.

  Examples of the addition polymerization resins include acrylic resins, acid vinyl resins, vinyl chloride resins, vinylidene chloride resins and hydrocarbon resins, and copolymers thereof. Examples of the acrylic resin include acrylic resins such as polyacrylic acid esters and polymethacrylic acid esters, and copolymers thereof. Examples of the vinyl acid resin include acrylic-styrene copolymer, acrylic-vinyl acetate copolymer, acrylic-vinyl chloride copolymer, acrylic-ethylene copolymer, polyvinyl acetate, vinyl acetate-vinyl chloride copolymer. Vinyl acetate-ethylene copolymer, vinyl acetate-styrene copolymer, and the like. Examples of the vinyl chloride resin include polyvinyl chloride, a vinyl chloride-acrylic copolymer, a vinyl chloride-ethylene copolymer, a vinyl chloride-styrene copolymer, and the like. Examples of the hydrocarbon resin include polyethylene, polypropylene, polybutadiene, chloroprene, polystyrene, polyisobutylene, styrene-butadiene copolymer, polyacrylonitrile, acrylonitrile-butadiene copolymer, fluorine resin, and silicone resin. In addition to these, synthetic resins modified with inorganic components can be used, and examples thereof include ceramic-modified fluororesins, ceramic-modified urethane resins, and ceramic-modified acrylic resins. In addition, composite resins containing two or more different types of polymers in the particles can also be used. Urethane / acrylic, epoxy / acrylic, silicone / acrylic, polyester / acrylic, fluororesin / acrylic, colloidal silica / acrylic, nitrocellulose / Examples thereof include acrylic and melamine resin / acrylic.

  Examples of the polycondensation resin include amide resins, imide resins, alkyd resins, phthalic resins, fatty acid-modified phthalic resins, phenol-modified phthalic resins, unsaturated polyester resins, and polycarbonates.

  Examples of the addition condensation resin include phenol resin, urea resin, urea melamine resin, and the like.

  In the adhesive composition of the present invention, the solid content concentration of the fine fibrous cellulose is 0.05% by mass or more and 3.0% from the viewpoint of handling properties and thickening with respect to 100% by mass of the total amount of the matrix resin and the fine cellulose. The range of mass% is preferable, and the range of 1.0 mass% to 2.0 mass% is more preferable.

[Other additives]
The adhesive composition of the present invention may contain various conventionally known additives depending on its use. For example, hydrolysis inhibitor, colorant, flame retardant, antioxidant, polymerization initiator, polymerization initiator Inhibitors, UV absorbers, antistatic agents, lubricants, mold release agents, antifoaming agents, leveling agents, light stabilizers (eg hindered amines), antioxidants, conductivity-imparting agents, slidability-imparting agents, interfaces Activators, catalysts, curing accelerators, inorganic fillers, organic fillers and the like can be mentioned. These additives can also be added in the above steps (2) to (4). However, the addition after the adjustment of the adhesive composition described later can be adjusted according to the use required as an adhesive. Is preferable.

  Moreover, a non-reactive solvent can also be added to the adhesive composition of this invention as needed. Examples of the non-reactive solvent include aliphatic hydrocarbon solvents such as hexane and mineral spirits; aromatic hydrocarbon solvents such as benzene, toluene and xylene; ester solvents such as butyl acetate; alcohols such as methanol and butanol Solvent; aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone and the like. These solvents may be used alone or in combination.

[Adjustment method of adhesive composition]
The adhesive composition of the present invention can be prepared by homogeneously kneading the cellulose nanofiber, the resin, and if necessary, various additive components. Examples of the kneader used at this time include a disper, a planetary mixer, a kneader, a Henschel mixer, a roll, and an extruder. Moreover, the produced adhesive composition can be applied to an adherend substrate by a usual method such as spraying, sealer gun, or brushing.

  Examples will be described together with comparative examples. However, the present invention is not limited to these examples. In the examples, “%” means mass basis unless otherwise specified.

  First, prior to Examples and Comparative Examples, cellulose fibers A1 to A4 for Examples and cellulose fibers A′1 and A′2 for Comparative Examples were prepared according to the following Production Examples 1 to 6.

[Production Example 1: Preparation of cellulose fiber A1 (for Examples)]
After adding 150 ml of water, 0.25 g of sodium bromide, and 0.025 g of TEMPO to 2 g of softwood pulp, and thoroughly stirring and dispersing, 13% sodium hypochlorite aqueous solution (co-oxidant) was added to 1.0 g of the above pulp. Was added so that the amount of sodium hypochlorite was 5.2 mmol / g, and the reaction was started. Since the pH decreased with the progress of the reaction, the reaction was carried out until no change in pH was observed while adding a 0.5N aqueous sodium hydroxide solution so that the pH was maintained at 10 to 11 (reaction time: 120 minutes). . After completion of the reaction, 0.1N hydrochloric acid was added for neutralization, followed by solid-liquid separation with a centrifuge, and pure water was added to adjust the solid content concentration to 4%. Thereafter, the pH of the slurry was adjusted to 10 with a 24% NaOH aqueous solution. The slurry was reduced to 30 ° C. by adding 0.2 mmol / g of sodium borohydride to the cellulose fiber and reacting for 2 hours. After the reaction, the reaction mixture was neutralized by adding 0.1N hydrochloric acid, and then purified by repeating filtration and washing to obtain cellulose fiber A1.

[Production Example 2: Preparation of cellulose fiber A2 (for Examples)]
Cellulose fiber A2 was obtained according to the preparation method of cellulose fiber A1, except that the amount of sodium hypochlorite aqueous solution added was 12.0 mmol / g with respect to 1.0 g of the pulp.

[Production Example 3: Preparation of cellulose fiber A3 (for Examples)]
100 g of softwood pulp was placed in a mixed solution of 435 g of isopropanol (IPA), 65 g of water and 9.9 g of NaOH, and stirred at 30 ° C. for 1 hour. To this slurry system was added 23.0 g of an IPA solution of 50% monochloroacetic acid, and the temperature was raised to 70 ° C. and reacted for 1.5 hours. The obtained reaction product was washed with 80% methanol, then substituted with methanol and dried to obtain cellulose fiber A3.

[Production Example 4: Preparation of cellulose fiber A4 (for Examples)]
20 g of urea, 12 g of sodium dihydrogen phosphate dihydrate, 8 g of disodium hydrogen phosphate were dissolved in 20 g of water to adjust the phosphorylating agent, and 20 g of softwood pulp (LBKP) pulverized with a home mixer was kneaded. Spraying with stirring, a phosphoric acid impregnated pulp was obtained. Next, phosphoric acid-impregnated pulp was heat-treated for 60 minutes in a blow dryer with a damper heated to 140 ° C. to obtain phosphorylated pulp. Water was added to the resulting phosphorylated pulp to a solid content concentration of 2%, and the mixture was stirred, mixed and uniformly dispersed, and then filtration and dehydration were repeated twice. Next, water was added to the obtained recovered pulp to obtain a solid content concentration of 2%, and a 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 to 13. Subsequently, this pulp slurry was filtered and dehydrated, and further, filtration and dehydration operations were repeated twice by adding water, followed by replacement with methanol and drying to obtain cellulose fibers A4.

[Production Example 5: Preparation of cellulose fiber A′1 (for comparative example)]
50 g of softwood bleached kraft pulp (NBKP) was dispersed in 4950 g of water to prepare a dispersion having a pulp concentration of 2%. This dispersion was treated 30 times with serendipeater MKCA6-3 (manufactured by Masuko Sangyo Co., Ltd.) to obtain cellulose fiber A′1.

[Production Example 6: Preparation of cellulose fiber A′2 (for comparative example)]
In addition to using regenerated cellulose in place of the raw conifer pulp and adding 27.0 mmol / g of sodium hypochlorite aqueous solution to 1.0 g of regenerated cellulose, the preparation method of cellulose fiber A1 Accordingly, cellulose fiber A′2 was prepared.

Each characteristic was evaluated according to the following evaluation method using the said cellulose fiber.

<Crystal structure>
Using an X-ray diffractometer (Rigaku Corporation, RINT-Utima3), the diffraction profile of cellulose fiber was measured, and typical at two positions, 2 theta = 14-17 ° and 2 theta = 22-23 °. When a typical peak was observed, the crystal structure (type I crystal structure) was evaluated as “present”, and when no peak was observed, it was evaluated as “none”.

<Measurement of carboxyl group content>
After preparing 60 ml of a cellulose aqueous dispersion in which 0.25 g of the above cellulose fiber is dispersed in water, the pH is adjusted to about 2.5 with a 0.1 M hydrochloric acid aqueous solution, and then a 0.05 M sodium hydroxide aqueous solution is added dropwise. The electrical conductivity was measured. The measurement was continued until the pH was 11. The amount of carboxyl groups was determined from the amount of sodium hydroxide consumed (V) in accordance with the following formula in the neutralization step of a weak acid with a gradual change in electrical conductivity.

<Measurement of the amount of carboxymethyl group>
The cellulose fiber is prepared in a slurry of 0.6% by mass and 0.1M hydrochloric acid aqueous solution is added to adjust the pH to 2.4, and then 0.05N sodium hydroxide aqueous solution is added dropwise until the pH reaches 11. , And the amount of carboxyl groups is measured from the amount of sodium hydroxide consumed in the neutralization step of the weak acid, where the change in electrical conductivity is gradual, and can be calculated using the following equation.

<Measurement of phosphate group amount>
The cellulose fiber was diluted with ion-exchanged water to a solid content concentration of 0.2% by mass, and then measured by treatment with an ion-exchange resin and titration with an alkali. In the treatment with an ion exchange resin, 1/10 by volume of a strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, conditioned) is added to a slurry containing 0.2% by mass of fine cellulose fibers and shaken for 1 hour. Went. Thereafter, the mixture was poured onto a mesh having an opening of 90 μm to separate the resin and the slurry. In titration using an alkali, a change in the value of electrical conductivity exhibited by the aqueous dispersion was measured while adding a 0.1N aqueous sodium hydroxide solution to the fine cellulose fiber aqueous dispersion after ion exchange. That is, the alkali amount [mmol] added until the value of electric conductivity was minimized was divided by the solid content [g] in the slurry to be titrated to obtain the phosphate group amount [mmol / g].

<Measurement of amount of carbonyl group>
About 0.2 g of the above cellulose fiber was precisely weighed, and precisely 50 ml of a 3 g / l aqueous solution of semicarbazide hydrochloride adjusted to pH = 5 with a phosphate buffer was added thereto, sealed, and shaken for 2 days. Next, 10 ml of this solution was accurately collected in a 100 ml beaker, 25 ml of 5N sulfuric acid and 5 ml of 0.05N potassium iodate aqueous solution were added and stirred for 10 minutes. Thereafter, 10 ml of a 5% potassium iodide aqueous solution was added, and immediately titrated with a 0.1N sodium thiosulfate solution using an automatic titrator. From the titration, etc., the amount of carbonyl group (aldehyde) in the sample was determined according to the following formula. Group and ketone group total content).

[Example 1]
Methanol was added to the cellulose fiber A1, filtered, and methanol washing was repeated to replace water contained in the cellulose fiber with methanol. Thereafter, methanol and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN Co., Ltd.) in an amount equal to the carboxyl group amount of the cellulose fiber A1 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer. (Sugino Machine Co., Ltd., Starburst) was used to perform the treatment once at a pressure of 100 MPa to obtain a gel composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the gel composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with bisphenol A. Thereafter, bisphenol A and dicyandiamide (Ajinomoto Co., Amicure AH-154) were added as a curing agent. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 150 ° C. for 1 hour to obtain a test piece.

  Each characteristic was evaluated according to the following evaluation method using the said gel-like composition, adhesive composition, and a test piece.

<Measurement of number average fiber diameter and aspect ratio>
The number average fiber diameter and fiber length of the cellulose fiber of the gel composition were observed using a transmission electron microscope (TEM, JEM-1400 manufactured by JEOL Ltd.). That is, after each cellulose fiber was cast on a hydrophilized carbon film-coated grid and negatively stained with 2% uranyl acetate, the number average fiber diameter was determined according to the method described above. And fiber length were calculated. Furthermore, the aspect ratio was calculated according to the following formula using these values.

<Evaluation of dispersion stability>
The adhesive composition was transferred to a test tube and allowed to stand overnight. The dispersibility was evaluated as follows according to the dispersion state of the cellulose fibers in the test tube.
○: Cellulose fibers were uniformly dispersed in the adhesive composition.
X: Cellulose fibers were precipitated in the adhesive composition.

<Evaluation of adhesive strength>
Using a universal testing machine (Instron Japan, Model 5581), the test piece was 2.5 mm / min. The tensile shear bond strength was measured in an atmosphere of 23 ° C. and 80 ° C. When <Evaluation of Dispersion Stability> is “x”, the adhesive strength was not evaluated.

<Evaluation of heat resistance>
From the tensile shear bond strength (S23) obtained by measurement at 23 ° C. and the tensile shear bond strength (S80) obtained by measurement at 80 ° C., the rate of decrease in tensile shear bond strength [% ] Was calculated. Evaluation was made based on the following criteria from the calculated rate of decrease in shear bond strength. In the above <Evaluation of dispersion stability>, when the cellulose fibers are settled, the heat resistance is not evaluated.

◎：９５％以上
○：９５％未満９０％以上
△：９０％未満８０％以上
×：８０未満

◎: 95% or more ○: Less than 95% 90% or more Δ: Less than 90% 80% or more ×: Less than 80

[Examples 2, 5-9, Comparative Example 1]
Polyetheramine as a modifier (manufactured by HUNTSMAN, JEFFAMINE M-2070) and cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration in the adhesive composition were changed as shown in Table 2 below. . Otherwise, a gel composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1, and each characteristic was evaluated.

Example 3
Add water to cellulose fiber A3, dilute to 1% solids, K. While stirring with 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX), 1N hydrochloric acid was added until the pH of the solution reached 2. Then, it filtered, wash | cleaned sufficiently with water, and also by repeating washing | cleaning with methanol, the acid type cellulose fiber A3 which carried out solvent substitution to methanol was produced. Methanol was added to the acid type cellulose fiber A3 and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN) in an amount equal to the amount of carboxyl groups of the cellulose fiber A3, diluted to 2%, and then a high-pressure homogenizer (Sugino) A gel-like composition was obtained by processing once at a pressure of 100 MPa using a machine manufacturer, Starburst. Modified bisphenol A (EPICLON 850S, manufactured by DIC) was added to the gel composition, and methanol was distilled off using a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with modified bisphenol A. Thereafter, bisphenol A and dicyandiamide (Ajinomoto Co., Amicure AH-154) were added as a curing agent. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 150 ° C. for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition, adhesive composition, and a test piece.

Example 4
Add water to cellulose fiber A4, dilute to 1% solids, K. While stirring with 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX), 1N hydrochloric acid was added until the pH of the solution reached 2. Then, it filtered, wash | cleaned sufficiently with water, and also by repeating washing | cleaning with methanol, the acid type cellulose fiber A4 which carried out solvent substitution to methanol was produced. Methanol is added to the acid type cellulose fiber A4 and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN) in an amount equal to the amount of phosphoric acid group of the cellulose fiber A4, diluted to 2%, and a high pressure homogenizer ( A gel-like composition was obtained by processing once at a pressure of 100 MPa using Starburst, manufactured by Sugino Machine. Bisphenol A (EPICLON 850S, manufactured by DIC) was added to the gel composition, and methanol was distilled off using a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with modified bisphenol A. Thereafter, bisphenol A and dicyandiamide (Ajinomoto Co., Amicure AH-154) were added as a curing agent. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 150 ° C. for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition, adhesive composition, and a test piece.

Example 10
Methanol was added to the cellulose fiber A2 and filtered, and methanol washing was repeated to replace the water contained in the cellulose fiber with methanol. Thereafter, methanol and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN Co., Ltd.) in an amount equal to the carboxyl group amount of the cellulose fiber A1 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer. (Sugino Machine Co., Ltd., Starburst) was used to perform the treatment once at a pressure of 100 MPa to obtain a gel composition. Toluene was added to the gel composition and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with toluene. Thereafter, toluene and polyvinyl acetate described in Table 2 below (Denkasacnol SN-10, manufactured by Denki Kagaku Kogyo Co., Ltd.) were further added. K. By stirring using a homomixer (manufactured by PRIMIX) at 8000 rpm × 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, and the matrix resin concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 150 ° C. for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition, adhesive composition, and a test piece.

Example 11
Methanol was added to the cellulose fiber A2 and filtered, and methanol washing was repeated to replace the water contained in the cellulose fiber with methanol. Thereafter, methanol and a polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN Co., Ltd.) in an amount equal to the carboxyl group amount of the cellulose fiber A2 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer. (Sugino Machine Co., Ltd., Starburst) was used to perform the treatment once at a pressure of 100 MPa to obtain a gel composition. An acrylic monomer (manufactured by Cemedine, Metallok Y610A) was added to the gel composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with an acrylic monomer. Thereafter, an acrylic monomer and a curing agent (manufactured by Cemedine, metal lock Y610B) are added as a matrix resin. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by leaving it at room temperature for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition, adhesive composition, and a test piece.

Example 12
Methanol was added to the cellulose fiber A2 and filtered, and methanol washing was repeated to replace the water contained in the cellulose fiber with methanol. Thereafter, methanol and a polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN Co., Ltd.) in an amount equal to the carboxyl group amount of the cellulose fiber A2 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer. (Sugino Machine Co., Ltd., Starburst) was used to perform the treatment once at a pressure of 100 MPa to obtain a gel composition. A nitrile rubber-based adhesive (manufactured by 3M, solvent-type adhesive EC776) was added to the gel composition, and methanol was removed by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.). Thereafter, MEK was added and T.M. K. By stirring using a homomixer (manufactured by PRIMIX) at 8000 rpm × 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, and the matrix resin concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by leaving it at room temperature for 1 hour to obtain a test piece.

Example 13
Methanol was added to the cellulose fiber A1, filtered, and methanol washing was repeated to replace water contained in the cellulose fiber with methanol. Thereafter, methanol and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN Co., Ltd.) in an amount equal to the carboxyl group amount of the cellulose fiber A1 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer. (Sugino Machine Co., Ltd., Starburst) was used to perform the treatment once at a pressure of 100 MPa to obtain a gel composition. A polyol (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Aimflex 318A) was added to the gel composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with the polyol. Thereafter, a polyol as a main agent and polyisocyanate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Aimflex 318B) as a curing agent are added. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. A cold-rolled steel plate having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 80 ° C. for 2 hours to obtain a test piece. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition, adhesive composition, and a test piece.

[Examples 14 and 15]
Cellulose fiber A1 is changed to cellulose fiber A2, and polyetheramine (manufactured by HUNTSMAN, JEFFAMINE M-2070) as a modifier is a polyetheramine (manufactured by HUNTSMAN, JEFFAMINE M-2070) / aliphatic amine. A gel composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1 except that the mixture was changed to a mixed solution (50/50 in molar ratio), and each characteristic was evaluated.

Example 16
Cellulose fiber A1 is changed to cellulose fiber A2, and polyetheramine (manufactured by HUNTSMAN, JEFFAMINE M-2070) as a modifier is a polyetheramine (manufactured by HUNTSMAN, JEFFAMINE M-2070) / aliphatic amine. Except for changing to a mixed solution (molar ratio 75/25), a gel composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1, and each characteristic was evaluated.

Example 17
Cellulose fiber A1 is changed to cellulose fiber A2, and polyetheramine (manufactured by HUNTSMAN, JEFFAMINE M-2070) as a modifier is a polyetheramine (manufactured by HUNTSMAN, JEFFAMINE M-2070) / aliphatic amine. Except for changing to a mixed solution (molar ratio 25/75), a gel composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1, and each characteristic was evaluated.

[Comparative Example 2]
Methanol was added to the cellulose fiber A3, filtered, and repeatedly washed with methanol to replace the water contained in the cellulose fiber with methanol. Thereafter, methanol was further added to dilute to 2%, and the mixture was treated once at a pressure of 100 MPa using a high-pressure homogenizer (manufactured by Sugino Machine, Starburst) to obtain a gel composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the gel composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with bisphenol A. Thereafter, bisphenol A as a main agent and dicyandiamide (Ajinomoto Co., Amicure AH-154) as a curing agent were added. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition and adhesive composition.

[Comparative Example 3]
Methanol was added to the cellulose fiber A′1, filtered, and washed repeatedly with methanol to replace the water contained in the cellulose fiber with methanol to obtain a gel composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the gel composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with bisphenol A. Thereafter, bisphenol A as a main agent and dicyandiamide (Ajinomoto Co., Amicure AH-154) as a curing agent were added. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition and adhesive composition.

[Comparative Example 4]
Cellulose fiber A′2 was diluted by adding water and freeze-dried. Methanol and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN) equivalent to the amount of carboxyl group of cellulose fiber A′2 were added to the lyophilized product and diluted to 2%, and then the high-pressure homogenizer (Sugino Machine) The product was processed once at a pressure of 100 MPa using a starburst, to obtain a gel composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the gel composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with bisphenol A. Thereafter, bisphenol A as a main agent and dicyandiamide (Ajinomoto Co., Amicure AH-154) as a curing agent were added. K. The mixture was stirred at 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX) to obtain an adhesive composition in which the cellulose fiber concentration, modifier concentration, matrix resin concentration, and curing agent concentration were adjusted as shown in Table 2. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 150 ° C. for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as Example 1 using the said gel-like composition, adhesive composition, and a test piece.

[Comparative Example 5].
An adhesive composition having a bisphenol A concentration of 94.6% (DIC Corporation, EPICLON 850S) and a dicyandiamide (Ajinomoto Co., Amicure AH-154) concentration adjusted to 5.4% was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 150 ° C. for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as in Example 1 using the test piece.

[Comparative Example 6]
The resin shown in Table 2 below was added to toluene to obtain an adhesive composition having a resin concentration adjusted to 20%. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 150 ° C. for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as in Example 1 using the test piece.

[Comparative Example 7].
An adhesive composition in which the acrylic monomer concentration was adjusted to 50% (Cemedine, Metal Lock Y610A) and the curing agent (Cemedine, Metal Lock Y610B) was adjusted to 50% was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by leaving it at room temperature for 1 hour to obtain a test piece. Each characteristic was evaluated by the same evaluation method as in Example 1 using the test piece.

[Comparative Example 8]
A cold rolled steel sheet with a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm is used as the adherend, and the nitrile rubber adhesive (solvent adhesive EC776, manufactured by 3M) is cured by leaving it at room temperature for 1 hour. A test piece was obtained. Each characteristic was evaluated by the same evaluation method as in Example 1 using the test piece.

[Comparative Example 9]
An adhesive composition in which the polyol concentration was adjusted to 59% and the polyisocyanate concentration was adjusted to 41% was obtained. A cold-rolled steel plate having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as the adherend, and the adhesive composition was cured by heating at 80 ° C. for 2 hours to obtain a test piece. Each characteristic was evaluated by the same evaluation method as in Example 1 using the test piece.

※1 ＨＵＮＴＳＭＡＮ社製、ＪＥＦＦＡＭＩＮＥ Ｍ−２０９５
※2 ＨＵＮＴＳＭＡＮ社製、ＪＥＦＦＡＭＩＮＥ Ｍ−２００５
※3 セメダイン社製、メタルロックＹ６１０Ａ
※4 セメダイン社製、メタルロックＹ６１０Ｂ
※5 溶剤であるトルエンを除いたときの濃度
※6 数平均繊維径が１ｎｍ以下であるため測定不可。

* 1 JEFFAMINE M-2095 manufactured by HUNTSMAN
* 2 JEFFAMINE M-2005, manufactured by HUNTSMAN
* 3 Metal Lock Y610A manufactured by Cemedine.
* 4 Metal Lock Y610B manufactured by Cemedine.
* 5 Concentration when toluene, the solvent, is removed * 6 Cannot be measured because the number average fiber diameter is 1 nm or less.

  From the results of Table 2 above, the adhesive compositions of the examples showed better results in terms of adhesive strength and heat resistance than the adhesive compositions of the resin alone of Comparative Examples 5-9. On the other hand, the adhesive composition of Comparative Examples 1 and 2 has insufficient hydrophobicity of the modifier, and the adhesive composition of Comparative Example 3 has no modifier. Aggregated and a good result was not obtained in terms of dispersion stability. In the adhesive composition of Comparative Example 4, the cellulose fibers were dispersed in the solvent without agglomeration. However, since the cellulose fibers did not have a crystal structure, the adhesive strength and heat resistance were not improved.

  Since the adhesive composition of the present invention has excellent heat resistance and adhesive strength, it is widely used in aerospace fields, electronics, civil engineering, architectural and other technical fields, automobiles, and automotive applications. be able to.

Claims (6)

An adhesive composition comprising fine fibrous cellulose satisfying the following conditions (A) to (E) and a matrix resin.
(A) Number average fiber diameter of 2 nm to 500 nm (B) Average aspect ratio of 10 to 1000 (C) Cellulose type I crystal structure (D) Anionic functional group (E) (D) A polyetheramine represented by the following formula (1) is bonded to a part or all of the anionic functional group.

[In the above formula (1), R ¹ , R ² and R ³ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and n1, n2 and n3 each represent 0 or more and 80 or less, (n1 + n2 + n3) represents 10 or more and 240 or less, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and the average value of x is 0.5 or more and 1 or less. The average value of y and z is 0 or more and 1 or less. ] The adhesive composition according to claim 1, wherein the fine fibrous cellulose further satisfies the following conditions.
(F) A polyether amine represented by the general formula (1) and an amine compound represented by the following general formula (2) are bonded to a part or all of the anionic functional groups described in (D).

[In the above formula (1), R ⁴ , R ⁵ and R ⁶ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom. ]   The adhesive composition according to claim 1 or 2, wherein the anionic functional group of the fine fibrous cellulose is a carboxyl group.   The matrix resin contains one or more selected from polycondensation resins, polyaddition polymerization resins, addition condensation resins, and addition polymerization resins. The adhesive composition according to any one of the above.   The adhesive composition according to any one of claims 1 to 4, wherein the matrix resin contains an epoxy resin, a urethane resin, an acrylic resin, an acid vinyl resin, and a hydrocarbon resin. . The adhesive composition according to any one of claims 1 to 5, wherein a solid content of the fine fibrous cellulose is in a range of 0.05% by mass to 3.0% by mass.