JP2018044098A - Coating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating agent excellent in low linear thermal expansion coefficient and the like.SOLUTION: A coating agent contains a fine fibrous cellulose satisfying the following conditions (A)-(E) and a monomer: (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 a coating agent.

  As a transparent plastic substrate for replacing glass, there is a demand for a transparent heat-resistant resin having flexibility and transparency, and having both heat resistance, a high glass transition point, and a low linear thermal expansion coefficient. As such materials, for example, super engineering plastics such as transparent polyimide and polyethersulfone are known. However, these materials have a high coefficient of linear thermal expansion, and are not sufficient as substitute materials for glass. In addition, the price is high and it is not economically suitable as an industrial product.

  By the way, an attempt has been made to enhance the properties of the resin by dispersing cellulose nanofibers obtained by oxidizing natural cellulose fibers in the presence of an N-oxyl compound in the resin. For example, in Patent Document 1, cellulose nanofibers introduced with hydrocarbon groups by amide bonds or ionic bonds and acrylic acid monomers, or methacrylic acid monomers, and then polymerized cellulose nanofibers and acrylic resin, or methacrylic monomers are mixed. It is described that a resin composite has a low coefficient of linear thermal expansion.

JP-A-2015-000935

  Cellulose nanofibers introduced with hydrocarbon groups by amide bonds or ionic bonds described in Patent Document 1 are not sufficiently effective in steric stabilization of alkyl groups in the side chain when blended with monomers. Since it is difficult to disperse the cured product, the linear expansion coefficient was not sufficiently lowered.

  An object of the present invention is to form a coating layer having excellent transparency, heat resistance, low linear thermal expansion coefficient, dimensional stability and antistatic properties by uniformly dispersing fine fibrous cellulose in a monomer. It is to provide a coating agent that can be used.

The present inventors have solved the above problems with a coating agent characterized by containing fine fibrous cellulose and a monomer.
That is, an object of the present invention is to provide the following [1] to [6].
[1] A coating agent comprising fine fibrous cellulose and monomers satisfying 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]に記載のコーティング剤。
（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 coating agent 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]記載のコーティング剤。
［４］上記モノマーがアクリル酸系モノマーおよび／またはメタクリル酸系モノマーであることを特徴とする［１］ないし［３］のいずれか１項に記載のコーティング剤。
［５］上記アクリル酸系モノマーおよび／またはメタクリル酸系モノマーが３官能以上であることを特徴とする［１］ないし［４］のいずれか１項に記載のコーティング剤。
［６］上微細繊維状セルロースの固形分含有量が、コーティング剤の重量全体の０．１質量％以上３．０質量％以下であることを特徴とする［１］から［５］のいずれか一項に記載のコーティング剤。

[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 coating agent according to [1] or [2], wherein the anionic functional group of the fine fibrous cellulose is a carboxyl group.
[4] The coating agent according to any one of [1] to [3], wherein the monomer is an acrylic acid monomer and / or a methacrylic acid monomer.
[5] The coating agent according to any one of [1] to [4], wherein the acrylic acid monomer and / or methacrylic acid monomer is tri- or more functional.
[6] Any of [1] to [5], wherein the solid content of the upper fine fibrous cellulose is 0.1% by mass or more and 3.0% by mass or less of the total weight of the coating agent. The coating agent according to one item.

  The coating agent of the present invention can produce a coating layer having transparency, heat resistance, low linear thermal expansion coefficient, dimensional stability and antistatic properties.

  The coating agent of the present invention contains a predetermined fine fibrous cellulose and a monomer.

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

<Number 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. When the number average fiber diameter is less than 2 nm, the fine fibrous cellulose dissolves, so that the crystal structure of the fine fibrous cellulose is lost, and the heat resistance, dimensional stability, and low linear thermal expansion coefficient of the coating layer are poor. If the number average fiber diameter exceeds 500 nm, the transparency of the coating layer may be insufficient. The maximum fiber diameter is preferably 1000 nm or less, particularly preferably 500 nm or less, from the viewpoint of the transparency of the coating layer.

  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. If the average aspect ratio is less than 10, the coating layer may have insufficient heat resistance, dimensional stability, transparency and low linear thermal expansion coefficient.

  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 (1).

<Cellulose I-type crystal structure>
The cellulose nanofiber 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 cellulose nanofiber 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 by having typical peaks at two nearby positions.

<Anionic functional group>
The cellulose nanofiber 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 carboxyl 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 hydroxyl group of cellulose The method of converting into a carboxyl group by oxidizing is 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 methods are mentioned as a method of introduce | transducing a phosphate group into a cellulose. 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 content of the anionic functional group 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 from the viewpoint of dispersibility of the fine fibrous cellulose in the monomer. The range is from 5 mmol / 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).

上記微細繊維状セルロースのアニオン性官能基量は、たとえばアニオン性官能基がカルボキシルメチル基の場合は以下の方法で測定する。すなわち、上記微細繊維状セルロースを０．６質量％スラリーに調製し、０．１Ｍ塩酸水溶液を加えてｐＨ２．４とした後、０．０５Ｎの水酸化ナトリウム水溶液を滴下してｐＨが１１になるまで電気伝導度を測定し、電気伝導度の変化が緩やかな弱酸の中和段階において消費された水酸化ナトリウム量からカルボキシル基量を測定し、下式を用いて算出することが出来る。

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>
A polyetheramine is bonded to the anionic functional group of the fine fibrous cellulose.

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〕が挙げられる。

[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挙げられる。

[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 fine fibrous cellulosic fiber of the present invention may have only one kind of the above polyetheramine, or may have two or more kinds.

<Amine compound>
Moreover, when a part of anionic functional 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 functional group.

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。上記Ｒ^４、Ｒ^５、Ｒ^６は炭素数２以上１８以下のアルキル基が好ましく、炭素数２以上８以下のアルキル基がより好ましい。

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, di diethyl methylamine, dioctadecyl methylamine being more preferred.

  When the above polyether amine and amine compound are used in combination, the mixing ratio is a polyether ratio in terms of molar ratio from the viewpoint of dispersibility of the fine fibrous cellulose in the monomer and the low linear thermal expansion coefficient and high elastic modulus of the coating layer to be produced. Amine / amine compound = 99/1 to 25/75 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 a monomer: Step of adding polyetheramine or the like to the cellulose fiber after substitution of the dispersion medium (4): Cellulose fibers bonded with the polyetheramine in the monomer 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 by 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 the monomer to replace water with the monomer.

(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.

<Step (3)>
Step (3) is a step of adding the polyether amine represented by the above formula (1) and, if necessary, the amine compound represented by the above formula (2) to the oxidized cellulose after the dispersion medium substitution. Thereby, the polyetheramine etc. which are shown by the said Formula (1) couple | bond with the carboxyl group of the said cellulose, and the lipophilicity of a cellulose is performed. In addition, the said reaction is performed in the said monomer.

<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. In addition, in this process, you may mix | blend the organic solvent mentioned later as needed.

[monomer]
The monomer that can be suitably used in the present invention is not particularly limited, and examples thereof include acrylic acid-based monomers, methacrylic acid-based monomers, and epoxy-based monomers. Among these, fine fibrous cellulose and monomers are compatible. To acrylic acid monomers and methacrylic acid monomers are preferred.

  Examples of the acrylic acid monomer include acrylic acid and its derivatives. On the other hand, examples of the methacrylic acid monomer include methacrylic acid and derivatives. These acrylic acid monomers and methacrylic monomers are polymerizable. Examples of the derivatives of acrylic acid include alkali metal salts of acrylic acid represented by CH2- = CHCOOR and esters of acrylic acid. Examples of the methacrylic acid derivative include alkali metal salts of methacrylic acid and esters of methacrylic acid represented by CH2- = C (CH3) COOR. In these formulas, R represents an alkali metal or alcohol residue. As acrylic acid monomers and methacrylic acid monomers, monofunctional monomers having one C═C double bond in one molecule and two monomers having two C═C double bonds in one molecule are used. A functional monomer or a polyfunctional monomer having 3 or more C═C double bonds in one molecule is used.

  In the above formulas, when R is an alkali metal, examples of the alkali metal include sodium. When R is an alcohol residue, examples of the alcohol include aliphatic alcohols having 1 to 50 carbon atoms and aromatic alcohols having 6 to 50 carbon atoms. Moreover, the polyalkylene glycol represented by R1- (OR2) n-OH is mention | raise | lifted. Examples of the aliphatic alcohol include saturated aliphatic alcohols and unsaturated aliphatic alcohols. These saturated aliphatic alcohols and unsaturated aliphatic alcohols may be modified with a functional group such as a hydroxyl group, an ether group, an ester group, or a carboxyl group. Examples of R1 in the polyalkylene glycol include an alkyl group having 1 to 50 carbon atoms. Examples of R2 include an alkylene group having 1 to 18 carbon atoms. For example, n is preferably an integer of 1 to 30.

  The acrylic monomer and methacrylic monomer are not particularly limited, but specific examples include methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, phenoxyethyl acrylate, methoxytriethylene glycol acrylate, methoxy Polyethylene glycol acrylate, phenyl glycidyl ether acrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, ethyl methacrylate, methacrylic acid Butyl, hexyl methacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pen Taerythritol triacrylate, dipentaerythritol hexaacrylate, etc. are mentioned.

  Of the acrylic acid monomers and methacrylic acid monomers, a trifunctional or higher functional acrylic acid monomer or methacrylic acid monomer is preferred from the viewpoint of heat resistance. The trifunctional or higher functional acrylic acid monomer or methacrylic acid monomer is not particularly limited, and specific examples include trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and the like.

  Examples of the epoxy monomer include butyl glycidyl ether, hexyl glycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and polypropylene glycol. Diglycidyl ether, neopentyl glycol diglycidyl ether, 1.6-hexanediol diglycidyl ether, glycerin diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, trimethylolpropane triglycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3 ', 4'-epoxycyclohexylmethyl-3,4-epoxy Rhohexanecarboxylate, 2,2-bis (hydroxymethyl) -1-butanol, 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct, ε-caprolactone modified 3 ′, 4′-epoxycyclohexylmethyl 3 , 4-epoxycyclohexanecarboxylate, 1,2-epoxy-4-vinylcyclohexane, limonene dioxide and the like.

  The solid content concentration of the fine fibrous cellulose in the coating agent of the present invention is 0.05% by mass or more and 3.0% with respect to the total amount of the monomer and the fine fibrous cellulose of 100% by mass from the viewpoint of handling properties and thickening. The range of mass% is preferable, and the range of 1.0 mass% or more and 2.0 mass% or less is more preferable.

  The coating agent of the present invention preferably contains an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the monomer; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, isopropanol, butanol, and isobutanol; ethyl acetate, butyl acetate, Examples include esters such as isobutyl acetate; and mixtures thereof. The amount in which the solid content of the coating agent of the present invention is in the range of 5% by mass to 50% by mass is preferable. If the monomer is liquid at room temperature and is suitable for coating, no organic solvent is required.

  The coating agent of the present invention preferably contains an aminosilane coupling agent in order to improve the adhesion to the substrate. Examples of such aminosilane coupling agents include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, and 3- (2-aminoethyl) amino. Examples include propyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, and 3-anilinopropyltrimethoxysilane. The content is preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the solid content of the coating agent of the present invention.

  The coating agent of the present invention can contain additives such as a dehydrating agent, a leveling agent, a thickener, and an ultraviolet absorber as necessary. Examples of the dehydrating agent include methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate and the like. Examples of the leveling agent include various polyether-modified silicone oils. The composition of the present invention can also be used as a paint by adding colorants such as various pigments and dyes, carbon black, charge control agents, aluminum paste, talc, glass frit, metal powder and the like.

  The base material to which the coating agent of the present invention is applied includes, on the material, metals such as iron, stainless steel, aluminum, alumite, and duralumin; metal oxides such as iron oxide, ferrite, alumina, and zinc oxide; mortar and slate And inorganic base materials such as concrete, glass and ceramic; wood, plywood; and resins such as thermosetting resin, thermoplastic resin and FRP. Examples of the shape of the substrate include a plate shape, a block shape, a film shape, a particle shape, and a powder shape.

  Examples will be described together with comparative examples. However, the present invention is not limited to these examples. In the examples, “%” means a weight 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 5.

[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.

＜カルボキシメチル基量の測定＞
上記セルロース繊維を０．６質量％スラリーに調製し、０．１Ｍ塩酸水溶液を加えてｐＨ２．４とした後、０．０５Ｎの水酸化ナトリウム水溶液を滴下してｐＨが１１になるまで電気伝導度を測定し、電気伝導度の変化が緩やかな弱酸の中和段階において消費された水酸化ナトリウム量からカルボキシル基量を測定し、下式を用いて算出することが出来る。

<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] mmol added until the value of electric conductivity was minimized was divided by the solid content [g] in the titration target slurry 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).

〔実施例１〕
上記セルロース繊維Ａ１にメタノールを加えてろ過し、メタノール洗浄を繰り返して、上記セルロース繊維に含まれる水をメタノールに置換した。その次に、ジペンタエリスリトールヘキサアクリレート（日本化薬社製、以下ＤＰＨＡと略す）を加えてろ過し、ＤＰＨＡ洗浄を繰り返して、上記セルロース繊維に含まれるメタノールをＤＰＨＡに置換した。その後、ＤＰＨＡと、上記セルロース繊維Ａ１のカルボキシル基量と等量のポリエーテルアミン（ＪＥＦＦＡＭＩＮＥ Ｍ−２０７０、ＨＵＮＴＳＭＡＮ社製）とを加えて、セルロース繊維濃度を０．５％になるように希釈し、高圧ホモジナイザー（スギノマシン社製、スターバースト）を用いて圧力１００ＭＰａで１回処理し、コーティング剤を得た。上記コーティング剤に開始剤として１−ヒドロキシシクロヘキシルフェニルケトンを添加（モノマー重量に対して３％重量）し、上記開始剤が溶解したことを確認した後、バーコーターを用いてコロナ処理したＰＥＴフィルム上に塗布した。その後、放射照度を約２００ｍＷ／ｃｍ^２とし、１分間紫外線を照射することで複合フィルムを作製した。
上記コーティング剤と上記複合フィルムを用いて、下記評価方法に従い、各特性の評価を行った。

[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. Next, dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., hereinafter abbreviated as DPHA) was added and filtered, and DPHA washing was repeated to replace methanol contained in the cellulose fiber with DPHA. Thereafter, DPHA and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN) in an amount equal to the carboxyl group amount of the cellulose fiber A1 are added, and the cellulose fiber concentration is diluted to 0.5%, Using a high-pressure homogenizer (manufactured by Sugino Machine, Starburst), it was processed once at a pressure of 100 MPa to obtain a coating agent. After adding 1-hydroxycyclohexyl phenyl ketone as an initiator to the coating agent (3% by weight with respect to the monomer weight) and confirming that the initiator was dissolved, on the PET film treated with corona using a bar coater It was applied to. Then, the irradiance was about 200 mW / cm ² and a composite film was produced by irradiating with ultraviolet rays for 1 minute.
Each characteristic was evaluated according to the following evaluation method using the coating agent and the composite film.

<Measurement of number average fiber diameter and aspect ratio>
The number average fiber diameter and fiber length of the cellulose fibers of the coating agent 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 transparency>
Using the composite film, the haze value was measured with a haze meter (NDH 4000, manufactured by Nippon Denshoku Industries Co., Ltd.). Transparency was evaluated as follows according to the magnitude of the haze value.
◎: Haze value of 0 or more and less than 0.25 ○: 0.25 or more and less than 0.5 Δ: 0.5 or more and less than 1 x: 1 or more

<Measurement of linear thermal expansion coefficient>
The thermal expansion coefficient of the composite film was measured using a tensile mode of a thermomechanical analyzer (manufactured by Rigaku Corporation, TMA8311). The temperature was increased from 0 ° C. to 300 ° C. at a rate of temperature increase of 5 ° C./min, a load of 7 mN and a nitrogen atmosphere, and the linear thermal expansion coefficient [ppm / K] was calculated from the sample elongation from 20 ° C. to 200 ° C.

<Measurement of dimensional stability>
Cut out the above composite film into a square (length 6cm x width 6cm) and stored at 20 ° C for 24 hours, then press the lowest point and calculate the average height ΔH (mm) of the other three points. did. The dimensional stability was evaluated as follows based on the average height ΔH.
◎: ΔH is 0 or more and less than 5 ○: 5 or more and less than 10 Δ: 10 or more and less than 15 x: 15 or more

<Measurement of indentation modulus>
The indentation elastic modulus of the composite film was measured using an ultra-fine indentation hardness tester (manufactured by Elionix, ENT-1100a). An ultrafine load (test load 0.3 mN, measurement temperature 26 ° C.) was applied to the composite film, and the indentation elastic modulus was calculated.

<Evaluation of antistatic properties>
Using the composite film, the surface resistivity [Ω] was measured with a digital ultrahigh resistance / microammeter (manufactured by ADVANTEST, R8340). The antistatic property was evaluated as follows according to the magnitude of the surface resistivity.
A: Surface resistivity value is less than 1.0 × 10 ¹¹ ○: 1.0 × 10 ¹¹ or more and less than 1.0 × 10 ¹³ Δ: 1.0 × 10 ¹³ or more and less than 1.0 × 10 ¹⁵ ×: 1. 0 × 10 ¹⁵ or more

<Evaluation of heat resistance>
Using a tensile mode of a viscoelasticity measuring apparatus (EXSTAR TMA6100, manufactured by SII Nano Technology Co., Ltd.), temperature range: −20 to 300 ° C., heating rate: 2 ° C./min, viscoelasticity of resin composition under nitrogen atmosphere Was measured. By this measurement, the value of the storage elastic modulus at each temperature is measured. When the storage elastic modulus at 20 ° C. is A and the storage elastic modulus at 200 ° C. is B, the heat resistance is defined by the following equation.

In general, since the storage elastic modulus decreases with temperature, A> B, and the heat resistance is 1 or less. The smaller the decrease from A to B, the closer the heat resistance is to 1. The closer this value is to 1, the higher the strength stability against heat. From the value calculated from the above formula, the heat resistance was evaluated as follows.
○: 0.5 or more Δ: 0.2 or more and less than 0.5 ×: less than 0.2

[Examples 2 to 15 and Comparative Example 1]
The cellulose fiber type, DPHA as a monomer, polyetheramine as a modifier (manufactured by HUNTSMAN, JEFFAMINE M-2070), and the cellulose fiber concentration in the coating agent were changed as shown in Table 2 below. Other than that, the coating agent and the composite film 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. Thereafter, filtration was performed, and the solution was sufficiently washed with water, and further repeatedly washed with methanol, whereby the solvent was replaced with methanol. Next, DPHA was added and filtered, and DPHA washing was repeated to prepare acid type cellulose fiber A3 in which methanol contained in the cellulose fiber was replaced with DPHA. DPHA and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN) in an amount equal to the carboxyl group amount of the acid type cellulose fiber A3 are added to the acid type cellulose fiber A3, and the cellulose fiber concentration is 0.5%. Then, it was treated once with a high pressure homogenizer (Sugino Machine, Starburst) at a pressure of 100 MPa to obtain a coating agent. After adding 1-hydroxycyclohexyl phenyl ketone as an initiator to the coating agent (3% by weight with respect to the monomer weight) and confirming that the initiator was dissolved, on the PET film treated with corona using a bar coater It was applied to. Then, the irradiance was about 200 mW / cm ² and a composite film was produced by irradiating with ultraviolet rays for 1 minute. Each characteristic was evaluated by the same evaluation method as in Example 1 using the coating agent and the composite film.

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. Thereafter, filtration was performed, and the solution was sufficiently washed with water, and further repeatedly washed with methanol, whereby the solvent was replaced with methanol. Next, DPHA was added and filtered, and DPHA washing was repeated to produce acid type cellulose fiber A4 in which methanol contained in the cellulose fiber was replaced with DPHA. DPHA and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN) having the same amount as the phosphate group of the cellulose fiber A4 are added to the acid type cellulose fiber A4, diluted to 2%, and a high pressure homogenizer ( A coating agent was obtained by performing treatment once at a pressure of 100 MPa using Starburst, manufactured by Sugino Machine. After adding 1-hydroxycyclohexyl phenyl ketone as an initiator to the coating agent (3% by weight with respect to the monomer weight) and confirming that the initiator was dissolved, on the PET film treated with corona using a bar coater It was applied to. Then, the irradiance was about 200 mW / cm ² and a composite film was produced by irradiating with ultraviolet rays for 1 minute. Each characteristic was evaluated by the same evaluation method as in Example 1 using the coating agent and the composite film.

[Examples 16 and 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. A coating agent and a composite film were prepared in the same manner as in Example 1 except that the mixed solution was changed to a mixed solution (50/50 in molar ratio), and each characteristic was evaluated.

Example 18
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 coating agent and a composite film were prepared in the same manner as in Example 1 except that the mixed solution (molar ratio 75/25) was changed, and each characteristic was evaluated.

Example 19
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 coating agent and a composite film were prepared in the same manner as in Example 1, and each characteristic was evaluated.

[Comparative Example 2]
Water and sodium hydroxide are added to the cellulose fiber A2 to dilute the cellulose fiber concentration to 0.5%, and the cellulose fiber A2 is treated once at a pressure of 100 MPa using a high-pressure homogenizer (manufactured by Sugino Machine, Starburst). did. Thereafter, T.W. K. While stirring with 8000 rpm × 10 minutes using a homomixer (manufactured by PRIMIX), 1N hydrochloric acid was added until the pH of the aqueous solution reached 2. Thereafter, filtration was performed, and the solution was sufficiently washed with water, and further repeatedly washed with methanol, whereby the solvent was replaced with methanol. Next, DPHA was added and filtered, and DPHA washing was repeated to produce acid-type cellulose fiber A2 in which methanol contained in the cellulose fiber was replaced with DPHA. DPHA and decylamine in an amount equal to the amount of carboxyl groups of the acid type cellulose fiber A2 are added to the acid type cellulose fiber A2 to dilute the cellulose fiber news soil to 0.5%, and a high pressure homogenizer (Sugino Using a machine company, Starburst), it was processed once at a pressure of 100 MPa to obtain a coating agent. After adding 1-hydroxycyclohexyl phenyl ketone as an initiator to the coating agent (3% by weight with respect to the monomer weight) and confirming that the initiator was dissolved in the monomer, PET subjected to corona treatment using a bar coater It was applied on a film. Then, the composite film was produced by carrying out UV hardening. Each characteristic was evaluated by the same evaluation method as in Example 1 using the coating agent and the composite film.

[Comparative Example 3]
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. Next, DPHA was added and filtered, and DPHA washing was repeated to replace the methanol contained in the cellulose fiber with DPHA. Thereafter, DPHA was further added to dilute to 0.5%, and the coating agent was obtained by treating once at a pressure of 100 MPa using a high-pressure homogenizer (manufactured by Sugino Machine, Starburst).

[Comparative Example 4]
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. Next, DPHA was added and filtered, and DPHA washing was repeated to replace the methanol contained in the cellulose fiber with DPHA. Thereafter, DPHA was further added to dilute the cellulose fiber concentration to 0.5% to obtain a coating agent.

[Comparative Example 5]
The cellulose fiber A′2 was diluted by adding water, and freeze-dried using a freeze dryer (FDU-2100, manufactured by Tokyo Rika Kikai Co., Ltd.) to obtain a dried product. DPHA and polyetheramine (JEFFAMINE M-2070, manufactured by HUNTSMAN Co., Ltd.) in an amount equal to the carboxyl group amount of the cellulose fiber A′2 are added to the dried product and diluted to 0.5%, and a high-pressure homogenizer (Sugino Using a machine company, Starburst), it was processed once at a pressure of 100 MPa to obtain a coating agent.

[Comparative Examples 6-12]
After adding 1-hydroxycyclohexyl phenyl ketone as an initiator to the monomers shown in Table 2 (3% by weight with respect to the monomer weight) and confirming that the initiator was dissolved in the monomer, corona treatment using a bar coater It was applied on the PET film. Then, the film was produced by carrying out UV hardening. Each characteristic was evaluated by the same evaluation method as Example 1 using the said film.

※1 ＨＵＮＴＳＭＡＮ社製、ＪＥＦＦＡＭＩＮＥ Ｍ−２００５
※2 ＨＵＮＴＳＭＡＮ社製、ＪＥＦＦＡＭＩＮＥ Ｍ−２０９５
※3 第一工業製薬社製、ニューフロンティア ＰＥＴ−０３
※4 第一工業製薬社製、ニューフロンティア ＴＭＰＴ
※5 第一工業製薬社製、ニューフロンティア Ｌ−Ｃ９Ａ
※6 第一工業製薬社製、ニューフロンティア ＴＭＰＴＭ
※7 ダイセル社製、セロキサイド２０２１Ｐ
※8 共栄社化学社製、エポライト１６００
※9 数平均繊維径が１ｎｍ以下であるため測定不可。
※10 モノマー中で微細繊維状セルロースが凝集し、複合フィルムを作製できなかったため測定不可。

* 1 JEFFAMINE M-2005, manufactured by HUNTSMAN
* 2 JEFFAMINE M-2095 manufactured by HUNTSMAN
* 3 Daiichi Kogyo Seiyaku Co., Ltd., New Frontier PET-03
* 4 New Frontier TMPT manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
* 5 New Frontier L-C9A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
* 6 New Frontier TMPTM, Daiichi Kogyo Seiyaku Co., Ltd.
* 7 Made by Daicel, Celoxide 2021P
* 8 Epolite 1600, manufactured by Kyoeisha Chemical Co., Ltd.
* 9 Cannot be measured because the number average fiber diameter is 1 nm or less.
* 10 Cannot be measured because fine fibrous cellulose aggregated in the monomer and composite film could not be produced.

  From the results of Table 2 above, the composite films obtained from the coating agents of the examples are more transparent, linear thermal expansion coefficient, dimensional stability, indentation elastic modulus, electrification than the films obtained from the monomers of Comparative Examples 6-12. Good results were obtained in terms of prevention and heat resistance. On the other hand, since the coating agent of Comparative Example 1 does not contain polyetheramine in the modifier and the fiber diameter is large, good results are obtained in terms of transparency, linear thermal expansion coefficient, and dimensional stability. I couldn't. Since the coating agent of Comparative Example 2 did not contain polyetheramine in the modifier, it was not uniformly dispersed in the monomer, and good results were not obtained in terms of linear thermal expansion coefficient. In addition, since the coating agent of Comparative Example 3 lacks the hydrophobic property of the modifying agent, and the coating agent of Comparative Example 4 does not have the modifying agent, fine fibrous cellulose aggregates in the monomer to produce a composite film. I couldn't even do it. Although the coating agent of Comparative Example 5 was good in terms of transparency and antistatic properties, since the cellulose fiber does not have a crystal structure, it has linear thermal expansion coefficient, dimensional stability, indentation elastic modulus, and heat resistance. Did not give good results

The coating agent of the present invention is excellent in transparency, heat resistance, low linear thermal expansion coefficient, dimensional stability and antistatic property, and therefore suitable as a coating agent for transparent thermoplastic resin plates instead of glass, touch panel surfaces of electronic devices, etc. Can be used.

Claims (6)

The coating agent characterized by containing the fine fibrous cellulose and monomer which satisfy | fill the following conditions (A)-(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.

[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 coating agent 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 coating agent according to claim 1 or 2, wherein the anionic functional group of the fine fibrous cellulose is a carboxyl group.   The coating agent according to any one of claims 1 to 3, wherein the monomer is an acrylic acid monomer and / or a methacrylic acid monomer.   The coating agent according to any one of claims 1 to 4, wherein the acrylic acid monomer and / or methacrylic acid monomer is trifunctional or more. 6. The coating agent according to claim 1, wherein a solid content of the upper fine fibrous cellulose is 0.1% by mass or more and 3% by mass or less of the total weight of the coating agent. .