JP2022053484A - Transparent coating agent - Google Patents

Abstract

To provide a transparent coating agent having excellent coatability.SOLUTION: A transparent coating agent contains a resin precursor or a resin, and modified cellulose fibers. The modified cellulose fibers have an average fiber length of 500 nm or less and are one or more selected from modified cellulose fibers (A) and/or modified cellulose fibers (B). The modified cellulose fibers (A): cellulose fibers having ionic groups, or modified cellulose fibers with modifying groups bound to the ionic groups. Modified cellulose fibers (B): modified cellulose fibers with modifying groups bound to hydroxy groups of cellulose fibers.SELECTED DRAWING: None

Description

The present invention relates to a transparent coating agent.

A coating layer is provided on various base materials for the purpose of protecting the surface of the base material, improving the function, and improving the aesthetic appearance. For example, a hard coat layer is provided on an optical display, eyeglasses, a window glass, a vehicle body surface, or the like for the purpose of preventing scratches. Further, for example, from the viewpoint of cosmeticity and visibility, a smooth / transparent clear coat layer is provided on a pharmaceutical label, a packaging container, or the like.

For example, Patent Document 1 discloses a coating agent containing a specific fine fibrous cellulose and a monomer, with an object of providing a coating agent having an excellent low coefficient of linear thermal expansion and the like.

Further, Patent Document 2 has an object of providing a film made of an ionized radiation curable resin composition having high mechanical properties such as breaking strength and breaking strain, from an ionized radiation curable resin composition on a support. A hard coat film produced by applying, drying, photocuring, and peeling from a support, and the coating liquid containing cellulose nanofibers is applied onto the support, dried, and dried. Described are hard coat films characterized by containing cellulose nanofibers by being photocured and then peeled off from the support.

Japanese Unexamined Patent Publication No. 2018-044098 JP-A-2015-200815

However, with the coating agents described in these patent documents, the coatability, that is, the appearance of the coating film after coating is not sufficient.

The present invention relates to a transparent coating agent having excellent coatability.

The present invention relates to the following [1].
[1] A transparent coating agent containing a resin precursor or a resin and a modified cellulose fiber, wherein the modified cellulose fiber has an average fiber length of 500 nm or less and the following modified cellulose fiber (A). And a transparent coating agent which is one or more selected from the group consisting of the modified cellulose fiber (B).
Modified cellulose fiber (A): Cellulose fiber containing an ionic group, or a modified cellulose fiber formed by binding a modifying group to the ionic group. Modified cellulose fiber (B): A modifying group is added to the hydroxy group of the cellulose fiber. Modified cellulose fiber that is bonded

According to the present invention, it is possible to provide a transparent coating agent having excellent coatability.

As a result of diligent studies by the inventors of the present invention, the transparent coating agent containing the modified cellulose fiber having a specific fiber length satisfies the function as a transparent coating agent such as surface hardness and transparency. At the same time, it was found to be excellent in coatability. It is considered that this is because the modified cellulose fiber has excellent dispersibility in the transparent coating agent.

[Transparent coating agent]
The transparent coating agent of the present invention contains a resin precursor or a resin and a modified cellulose fiber. In the present specification, the transparent coating agent is a coating agent that makes the film obtained when applied to a base material transparent, and is applied for the purpose of protecting the base material, improving the function, and improving the aesthetic appearance. It is an agent and is sometimes called varnish. Examples of the base material include transparent members such as optical displays, eyeglasses, and windowpanes, automobile body surfaces, paper-based materials, wood-based materials, and packaging materials / labels such as plastic films.

[Resin precursor or resin]
Examples of the resin precursor contained in the transparent coating agent of the present invention include curable monomers, prepolymers, oligomers and the like.

Examples of the monomer suitably usable for the transparent coating agent of the present invention include acrylic acid-based monomers, methacrylic acid-based monomers, and epoxy-based monomers.

The acrylic acid-based monomer and the methacrylic acid-based monomer are not particularly limited, and examples thereof include acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, and methacrylicamide, and more specifically, methyl acrylate and acrylic acid. Ethyl, butyl acrylate, hexyl acrylate, lauryl acrylate, stearyl acrylate, 2-hedroxyethyl acrylate, isobutyl acrylate, 2-methoxyethyl acrylate, cyclohexyl acrylate, dimethylaminoethyl acrylate, phenoxyethyl acrylate, acryloylmorpholine, ethoxy -Diethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxypolyethylene glycol acrylate, phenylglycidyl ether acrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, trimethylpropantriacrylate, dipentaerythritol hexaacrylate, Examples thereof include ethyl methacrylate, butyl methacrylate, hexyl methacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate.

Of the acrylic acid-based monomers and methacrylic acid-based monomers, monofunctional or polyfunctional acrylic acid esters or methacrylic acid esters are preferable, and polyfunctional acrylic acid esters are preferable from the viewpoint of improving the coatability of the transparent coating agent of the present invention. Alternatively, a methacrylic acid ester is more preferable, and a trifunctional or higher functional acrylic acid ester or a methacrylic acid ester is further preferable. The trifunctional or higher functional acrylic acid ester or methacrylic acid ester is not particularly limited, and specific examples thereof include trimethylolpropane trimetaacrylate, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate.

Examples of the epoxy-based 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-epoxycyclohexanecarboxylate, 2,2-bis (hydroxymethyl) -1-butanol, 1,2-epoxy-4- (2-oxylanyl) cyclohexane adduct , Ε-caprolactone modified 3', 4'-epoxycyclohexylmethyl, 3,4-epoxycyclohexanecarboxylate, 1,2-epoxy-4-vinylcyclohexane, limonendioxide and the like.

Examples of the prepolymer and oligomer serving as a resin precursor include polymerizable compounds having a reactive group that can be cured by a cross-linking reaction. Preferred reactive groups include, for example, an epoxy group, a carboxy group, an amino group, an isocyanate group, an aldehyde group, a hydroxy group, a vinyl group, an acryloyl group, an allyl group, a silanol group and the like, and one of these is used alone. Alternatively, two or more types can be used in combination. The type of resin obtained by polymerizing the polymerizable compound can be selected according to the intended use, desired characteristics or physical characteristics, and may be any of a thermosetting resin, a photocurable resin and a thermoplastic resin.

Examples of the thermosetting resin obtained by polymerizing the polymerizable compound include epoxy resin, unsaturated polyester resin, vinyl ester resin, acrylic resin, phenoxy resin, phenol resin, urea resin, melamine resin, aniline resin, and polyimide resin. , Bismaleimide resin, silicone resin, urethane resin and the like. Among these, epoxy resin, acrylic resin, phenoxy resin, phenol resin, and urethane resin are preferable, and acrylic resin is more preferable, because a dispersion liquid having excellent dispersibility can be obtained. The acrylic resin may be obtained by copolymerizing acrylic acid or methacrylic acid with other monomers such as styrene and succinic anhydride.

In the transparent coating agent of the present invention, a curing agent or a curing accelerator may be further blended in addition to the resin precursor. That is, the composition containing the resin precursor may be composed of the resin precursor, the modified cellulose fiber described later, and a curing agent or a curing accelerator for the resin precursor.

The curing agent can be appropriately selected depending on the type of resin precursor. For example, the curing agent in the case of thermal curing includes, for example, an amine-based curing agent, a phenol resin-based curing agent, an acid anhydride-based curing agent, and poly. Examples thereof include mercaptan-based curing agents and latent curing agents (boron trifluoride-amine complex, dicyandiamide, carboxylic acid hydrazide, etc.). In the case of ultraviolet curing, the curing agent includes benzyl, benzophenone and its derivatives, thioxanthones, benzyl dimethyl ketals, α-hydroxyalkylphenones, α-hydroxyacetophenones, hydroxyketones, aminoalkylphenones, and acyls. Examples include phosphinoxides. Specifically, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane-1-one, benzylmethylketone, 1- (4-dodecylphenyl) -2- Examples thereof include hydroxy-2-methylpropane-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-one, benzophenone and the like. Commercially available products include "IRGACURE651", "IRGACURE184", "IRGACURE500", "IRGACURE1000", "IRGACURE2959", "DAROCUR1173", "IRGACURE127", "IRGACURE907", "IRGACURE369", "IRGACURE369", "IRGACURE369" "IRGACURE1800", "IRGACURE819", "IRGACURE784" [The above IRGACURE series and DAROCUR series are trade names manufactured by BASF Japan Ltd.], "KAYACUREITX", "KAYACUREDETX-S". KAYACUREBP-100 ”,“ KAYACUREBMS ”,“ KAYACURE2-EAQ ”[The above KAYACURE series is a trade name manufactured by Nippon Kayaku Co., Ltd.] and the like. And so on. The curing agent may be used alone or in combination of two or more. The curing agent may act as a curing accelerator.

The ratio of the curing agent can be appropriately selected depending on the type of the resin precursor and the curing agent, and is, for example, preferably 0.1 to 300 parts by mass with respect to 100 parts by mass of the resin precursor.

The curing accelerator can also be appropriately selected depending on the type of the resin precursor. For example, examples of the curing accelerator in the case of an epoxy resin include phosphines, amines, ureas and the like. Examples of the curing accelerator in the case of an acrylic resin include tertiary amines (dialkylaminobenzoic acid ester and the like), phosphine-based accelerators, tin compounds, metal salts, bases and the like. The curing accelerator may be used alone or in combination of two or more.

The ratio of the curing accelerator can be appropriately selected depending on the type of the curing agent and the like, but is preferably 0.01 to 100 parts by mass with respect to 100 parts by mass of the resin precursor, for example.

Examples of the resin contained in the transparent coating agent of the present invention include acrylic resins, urethane resins, water-soluble vinyl acetates, polyvinyl alcohols, cyanoacrylates, ethylene vinyl acetates, vinyl chlorides, and vinyl resins such as vinyl chloride-vinyl acetate copolymers. Cellulous resins such as ethyl cellulose, cellulose acetate, nitrocellulose, polyamide resins, polyvinyl acetal resins, diallyl phthalate resins, alkyd resins, rosin-modified alkyd resins, petroleum resins, urea resins, rubber resins such as butadiene-acrylic nitrile copolymers. From the viewpoint of dispersibility of the modified cellulose fiber described later, acrylic resin or urethane resin is preferable. The acrylic resin may be obtained by copolymerizing a monofunctional or polyfunctional acrylic acid ester or methacrylic acid ester. Further, it may be obtained by copolymerizing acrylic acid or methacrylic acid with other monomers such as styrene and succinic anhydride.

The content of the resin precursor or the resin in the transparent coating agent of the present invention is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass from the viewpoint of reducing the work load such as drying. % Or more, more preferably 10% by mass or more, still more preferably 30% by mass or more, and from the viewpoint of obtaining a cured film, preferably 99.5% by mass or less, more preferably 99% by mass or less, still more preferably. It is 98% by mass or less, more preferably 90% by mass or less, still more preferably 70% by mass or less.

[Modified cellulose fiber]
The modified cellulose fiber contained in the transparent coating agent of the present invention is one or more selected from the group consisting of the following modified cellulose fiber (A) and modified cellulose fiber (B), and is one or more of the modified cellulose fibers (A). In), from the viewpoint of coatability, those containing one or more modifying groups selected from the group consisting of (a) a hydrocarbon group, (b) a silicone chain, and (c) an alkylene oxide chain are preferable. .. From the viewpoint of specific puncture strength and water resistance, cellulose fibers containing unmodified ionic groups are preferable.
Modified cellulose fiber (A): Cellulose fiber containing an ionic group, or a modified cellulose fiber formed by binding a modifying group to the ionic group. Modified cellulose fiber (B): A modifying group is added to the hydroxy group of the cellulose fiber. Modified cellulose fiber that is bonded

As the cellulose fiber as a raw material of the modified cellulose fiber, it is preferable to use a natural cellulose fiber from the viewpoint of environmental load. Examples of the natural cellulose fiber include wood pulp such as coniferous tree pulp and broadleaf tree pulp; cotton pulp such as cotton linter and cotton lint; non-wood pulp such as straw pulp and bagas pulp; and bacterial cellulose and the like. One of these can be used alone or in combination of two or more.

The average fiber diameter and average fiber length of the raw material cellulose fiber are not particularly limited. The average fiber diameter is, for example, preferably 1 μm or more from the viewpoint of availability, and preferably 100 μm or less from the same viewpoint. The average fiber length is, for example, preferably 1000 μm or more from the viewpoint of availability, and preferably 10,000 μm or less from the same viewpoint. The average fiber diameter and the average fiber length of the raw material cellulose fiber can be measured by the method described in Examples described later.

<Modified Cellulose Fiber (A)>
The modified cellulose fiber (A) in the present invention is a cellulose fiber containing an ionic group or a modified cellulose fiber in which a modifying group is bonded to the ionic group.

(Ionic group)
The cellulose fiber containing an ionic group is a cellulose fiber modified so as to contain an ionic group in the cellulose fiber.

Examples of the ionic group include anionic group and cationic group. In the present specification, the cellulose fiber having an anionic group is also referred to as "anionic modified cellulose fiber". Examples of the anionic group include a carboxy group, a sulfonic acid group, a phosphoric acid group and the like, and examples of the cationic group include a group having onium such as ammonium, phosphonium and sulfonium in the group. From the viewpoint of introduction efficiency into the modified cellulose fiber (A), an anionic group is preferable as the ionic group, and a carboxy group is more preferable as the anionic group.

When the ionic group is an anionic group, the ion (counter ion) paired with the anionic group is one or more selected from the group consisting of metal ions and protons. The metal ion is preferably a monovalent cation, and examples thereof include alkali metal ions such as lithium ion, sodium ion, and potassium ion. From the viewpoint of reaction efficiency to the modified cellulose fiber, it is preferably a proton.

The content of the ionic group in the cellulose fiber containing an ionic group is preferably 0.1 mmol / g or more, more preferably 0.4 mmol / g or more, still more preferably, from the viewpoint of stable miniaturization and introduction of a modifying group. Is 0.6 mmol / g or more. From the same viewpoint, the upper limit is preferably 3.0 mmol / g or less, more preferably 2.0 mmol / g or less, still more preferably 1.8 mmol / g or less. When the ionic group is an anionic group, the content of the anionic group can be measured by the method described in Examples described later.

(Modifying group)
The modified cellulose fiber (A) includes an embodiment in which a modifying group is bonded to an ionic group of the cellulose fiber containing an ionic group. Examples of the bonding mode here include ionic bonds and covalent bonds (for example, amide bonds, ester bonds, urethane bonds, etc.).

As the modifying group in the modified cellulose fiber (A), one or more modifying groups selected from the group consisting of (a) a hydrocarbon group, (b) a silicone chain, and (c) an alkylene oxide chain can be used. Those containing are preferable. These groups may be introduced into the modified cellulose fiber (A) alone or in combination of two or more.

The number of carbon atoms of the hydrocarbon group as a modifying group is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more from the viewpoint of coatability, surface hardness and transparency, and is preferable from the same viewpoint. Is 30 or less, more preferably 24 or less, still more preferably 18 or less. The carbon number of the hydrocarbon group means the number of carbon atoms in one modifying group unless otherwise specified.

Specific examples of the chain saturated hydrocarbon group include, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, and a tert-pentyl group. Examples thereof include an isopentyl group, a hexyl group, an isohexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a dodecyl group, a tridecyl group, a tetradecyl group, an octadecyl group, a docosyl group and an octacosanyl group.

Specific examples of the chain unsaturated hydrocarbon group include an ethylene group, a propylene group, a butene group, an isobutene group, an isoprene group, a pentene group, a hexene group, a heptene group, an octene group, a nonene group, a decene group, and a dodecene group. , Tridecene group, tetradecene group, octadecene group and the like.

Specific examples of the cyclic saturated hydrocarbon group include, for example, a cyclopropane group, a cyclobutyl group, a cyclopentane group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cyclododecyl group, and a cyclotridecyl group. , Cyclotetradecyl group, cyclooctadecyl group and the like.

As the aromatic hydrocarbon group, for example, it is selected from the group consisting of an aryl group and an aralkyl group. As the aryl group and the aralkyl group, the aromatic ring itself may be substituted or unsubstituted.

Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a biphenyl group, a triphenyl group, a terphenyl group, and a group in which these groups are substituted with a substituent described later.

Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylpentyl group, a phenylhexyl group, a phenylheptyl group, a phenyloctyl group, and a group in which the aromatic group of these groups is further substituted with a substituent. And so on.

When the modifying group is a hydrocarbon group and the hydrocarbon group has a substituent, the substituent is, for example, a linear or branched alkoxy group having 1 to 6 carbon atoms; the alkoxy group has 1 to 6 carbon atoms. Linear or branched alkoxycarbonyl group; halogen atom such as bromine atom, iodine atom; acyl group having 1 to 6 carbon atoms; aralkyl group; aralkyloxy group; alkylamino group having 1 to 6 carbon atoms; carbon of alkyl group Dialkylamino groups having a number of 1 to 6, hydroxy groups, ethers, amides and the like may be used. The above-mentioned various hydrocarbon groups themselves may be bonded to another hydrocarbon group as a substituent.

The silicone chain is a monovalent group having a siloxane bond as a main chain, and may be further accompanied by an alkylene group. The silicone chain may further have a substituent.

Examples of the alkylene oxide chain include ethylene oxide / propylene oxide (EO / PO) copolymerization sites. The (EO / PO) copolymerization site means a structure in which ethylene oxide (EO) and propylene oxide (PO) are polymerized randomly or in a block shape. Examples of the group to which the (EO / PO) copolymerization moiety is bonded to the alkyl group include a group represented by the following formula (i'), which can be introduced using a compound of the following formula (i).

[In the formula, R ¹ represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or an aminoalkyl group thereof, EO and PO exist in a random or block form, and a is the average of EO. A positive number indicating the number of added moles, b is a positive number indicating the average number of added moles of PO. Here, the "amino alkyl group thereof" means a group in which one of the hydrogen atoms constituting the linear or branched alkyl group having 1 to 6 carbon atoms is substituted with an amino group. In formula (i), an alkylene group having 1 to 3 carbon atoms may be present between the amino group and EO or PO. ]

R ¹ is preferably a hydrogen atom from the viewpoint of coatability, surface hardness, and transparency. When R ¹ is a linear or branched alkyl group having 1 to 6 carbon atoms, the alkyl group is preferably a methyl group, an ethyl group, an n-propyl group and a sec-propyl group.

From the viewpoints of coatability, surface hardness, and transparency, a is preferably 1 or more, more preferably 3 or more, still more preferably 6 or more, still more preferably 11 or more, still more preferably 15 or more, still more preferably 20 or more. , More preferably 25 or more, still more preferably 30 or more. From the same viewpoint, it is preferably 100 or less, more preferably 70 or less, still more preferably 60 or less, still more preferably 50 or less, still more preferably 40 or less.

b is preferably 1 or more, more preferably 3 or more, and further preferably 5 or more from the viewpoint of coatability, surface hardness, and transparency. From the same viewpoint, it is preferably 50 or less, more preferably 40 or less, still more preferably 30 or less, still more preferably 25 or less, still more preferably 20 or less, still more preferably 15 or less, still more preferably 10 or less.

Examples of the alkylene group having 1 to 3 carbon atoms include a methylene group, an ethylene group and a propylene group.

The PO content (mol%) in the (EO / PO) copolymer site can be calculated based on the above a and b, and specifically can be obtained from b × 100 / (a + b). can. The PO content is preferably 1 mol% or more, more preferably 5 mol% or more, still more preferably 7 mol% or more, still more preferably 10 mol% or more from the viewpoint of coatability, surface hardness and transparency. .. From the same viewpoint, it is preferably 100 mol% or less, more preferably 90 mol% or less, still more preferably 85 mol% or less, still more preferably 75 mol% or less, still more preferably 60 mol% or less, still more preferably 50 mol%. Below, it is more preferably 40 mol% or less, still more preferably 30 mol% or less.

The molecular weight of the (EO / PO) copolymer site is preferably 100 or more, more preferably 200 or more, still more preferably 300 or more, still more preferably 500 or more, still more preferably 500 or more, from the viewpoint of coatability, surface hardness, and transparency. It is 1,000 or more, more preferably 1,500 or more. From the same viewpoint, it is preferably 10,000 or less, more preferably 7,000 or less, still more preferably 5,000 or less, still more preferably 4,000 or less, still more preferably 3,500 or less, still more preferably 2,500. It is as follows.

The amine having an EO / PO copolymerization site represented by the formula (i) is a modifying compound for introducing a modifying group represented by the formula (i'), and details of the amine can be described in, for example, Patent No. It is described in Japanese Patent Application Laid-Open No. 6105139.

As the amine having an EO / PO copolymerization site (also referred to as "EOPO amine"), for example, a commercially available product can be preferably used, and specific examples thereof include Jeffamine M-2070 and Jeffamine M- manufactured by HUNTSMAN. 2005, Jeffamine M-2095, Jeffamine M-1000, Jeffamine M-600, Surfoamine B200, Surfoamine L100, Surfoamine L200, Surfoamine L207, Surfoamine L207, Surfoamine L207, Surfoamine L207, Surfoamine L200, Surfoamine L207, Surfoamine L200, Surfoamine L207, Surfoamine L207, Surfoamine L. M3000, Jeffamine ED-900, Jeffamine ED-2003, Jeffamine D-2000, Jeffamine D-4000, XTJ-510, Jeffamine T-3000, Jeffamine T-5000, XTJ-502, XTJ-509, etc. Can be mentioned.

The average bond amount of the modifying group in the modified cellulose fiber (A) is preferably 0.01 mmol / g or more, more preferably 0.05 mmol / g or more, still more preferably, from the viewpoint of coatability, surface hardness, and transparency. Is 0.1 mmol / g or more, more preferably 0.3 mmol / g or more, still more preferably 0.5 mmol / g or more. From the same viewpoint, it is preferably 3.0 mmol / g or less, more preferably 2.5 mmol / g or less, still more preferably 2.0 mmol / g or less, still more preferably 1.8 mmol / g or less, still more preferably 1.5 mmol. It is less than / g. When any two or more kinds of modifying groups are simultaneously introduced into the modified cellulose fiber (A) as modifying groups, the average binding amount of the modifying groups is such that the total amount of the introduced modifying groups is within the above range. Is preferable.

The introduction rate of the modifying group in the modified cellulose fiber (A) is preferably 10 mol% or more, more preferably 30 mol% or more, still more preferably 50 mol% or more from the viewpoint of coatability, surface hardness, and transparency. More preferably 60 mol% or more, further preferably 70 mol% or more, and from the same viewpoint, preferably 99 mol% or less, more preferably 97 mol% or less, still more preferably 95 mol% or less, still more preferably. It is 90 mol% or less. When any two or more kinds of modifying groups are introduced at the same time as the modifying group, it is preferable that the total introduction rate is within the above range within the range not exceeding the upper limit of 100 mol%.

The average bond amount and introduction rate of the modifying group can be adjusted by adjusting the addition amount and type of the compound for introducing the modifying group, that is, the modifying compound, the reaction temperature, the reaction time, the type of the solvent and the like. The average binding amount (mmol / g) and introduction rate (mol%) of the modifying group are the amount and ratio of the modifying group introduced (bonded) to the ionic group in the modified cellulose fiber (A). be. The average bond amount and introduction rate of the modifying group are calculated by the method described in Examples described later, for example, when the ionic group is an anionic group.

(Manufacturing method of modified cellulose fiber (A))
The modified cellulose fiber (A) can be produced according to a known method without particular limitation as long as a cellulose fiber containing an ionic group can be prepared and a modifying group can be introduced into the ionic group. .. For example, when the ionic group is a carboxy group, the modified cellulose fiber (A) can be produced by referring to paragraphs 0017 to 0106 of JP-A-2018-024967. When the ionic group is a sulfonic acid group, examples of the method of introducing the sulfonic acid group into the cellulose fiber include a method of adding sulfuric acid to the cellulose fiber and heating the cellulose fiber. When the ionic group is a phosphoric acid group, as a method for introducing a phosphoric acid group into a cellulose fiber, a method of mixing a powder or an aqueous solution of phosphoric acid or a phosphoric acid derivative with a dry or wet state cellulose fiber, or a method of mixing cellulose. Examples thereof include a method of adding an aqueous solution of phosphoric acid or a phosphoric acid derivative to a dispersion liquid of fibers. Examples of the method for introducing a modifying group include a method of mixing a compound having a modifying group and a cellulose fiber having a phosphoric acid group. When the ionic group is a cationic group, examples of the method of introducing the cationic group into the cellulose fiber include a method of treating the cellulose fiber with a cationizing agent in the presence of an alkali. In the production of the modified cellulose fiber (A), the low aspect ratio treatment and the miniaturization step in JP-A-2018-024967 can be omitted.

<Modified Cellulose Fiber (B)>
The modified cellulose fiber (B) in the present invention is a modified cellulose fiber in which a modifying group is bonded to the hydroxy group of the cellulose fiber.

(Modifying group)
In the modified cellulose fiber (B), the cellulose fiber and the modifying group are bonded via an ether bond. In addition, in this specification, "bonding through an ether bond" means a state in which a modifying group reacts with a hydroxy group of a cellulose fiber, and an ether bond is formed.

The modifying group in the modified cellulose fiber (B) is preferably a hydrocarbon group which may have a substituent. Here, among the hydrocarbon groups which may have a substituent, the hydrocarbon group may be a saturated or unsaturated linear or branched aliphatic hydrocarbon group, an aromatic hydrocarbon group such as a phenyl group, or an aromatic hydrocarbon group. Examples thereof include an alicyclic hydrocarbon group such as a cyclohexyl group. Further, in the hydrocarbon group which may have a substituent in the present invention, examples of the substituent include an oxyalkylene group such as a halogen atom and an oxyethylene group, a hydroxy group and the like.

As a preferred embodiment of the modified cellulose fiber (B) (referred to as “aspect 1”), for example, a modifying group represented by the following general formula (1) and a modification represented by the following general formula (2). One or more modifying groups selected from the groups are bonded to the cellulose fibers via an ether bond, and examples thereof include those having a cellulose I-type crystal structure.
-CH ₂ -CH (R ⁰ ) -R ¹ (1)
-CH ₂ -CH (R ⁰ ) -CH _2- (OA) _n -O-R ¹ (2)
[In the formula, R ⁰ in the general formula (1) and the general formula (2) represents a hydrogen atom or a hydroxy group, and R ¹ is an independent hydrogen atom or carbon number 1 or more, preferably carbon number 3 or more and 30 or less. In the general formula (2), n is a number of 0 or more and 50 or less, and A is a linear or branched divalent saturated hydrocarbon group having 1 or more and 6 or less carbon atoms. ]

As a specific example of the first aspect, for example, the modified cellulose fiber represented by the following general formula (3) is exemplified.

[In the formula, R is the same or different, and indicates hydrogen, or a modifying group selected from the modifying group represented by the general formula (1) and the modifying group represented by the general formula (2). However, this does not apply when all Rs are hydrogen at the same time. m is preferably an integer of 20 or more and 3000 or less. ]

The modified cellulose fiber (B) represented by the general formula (3) has a repeating structure of the cellulose unit into which the modifying group has been introduced. As the number of repetitions of the repeating structure, m in the general formula (3) is preferably an integer of 20 or more and 3000 or less from the viewpoint of coatability, surface hardness, and transparency.

(Hydrocarbon group which may have a substituent)
The modified cellulose fiber (B) of the first aspect may contain one or more modifying groups selected from the modifying groups represented by the above general formula (1) and the following general formula (2) alone or arbitrarily. Introduced in combination. In addition, even if the modifying group to be introduced is any one of the above modifying group groups, the same modifying group may be introduced in each modifying group group, or two or more kinds may be introduced in combination.

From the viewpoint of coatability, surface hardness, and transparency, R ⁰ in the general formula (1) and the general formula (2) is preferably a hydroxy group.

The carbon number of R ¹ in the general formula (1) is preferably 25 or less from the viewpoint of coatability, surface hardness, and transparency. Specifically, a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, and a hexadecyl group. Examples thereof include a group, an octadecyl group, an isooctadecyl group, an icosyl group, a triacontyl group, a phenyl group, and a methylphenyl group.

The carbon number of R ¹ in the general formula (2) is preferably 4 or more from the viewpoint of coatability, surface hardness, and transparency, and preferably 27 or less from the viewpoint of improving availability and reactivity. Specifically, the same as R ¹ in the above-mentioned general formula (1) can be mentioned.

A in the general formula (2) forms an oxyalkylene group with an adjacent oxygen atom. The carbon number of A is preferably 2 or more from the viewpoint of availability and cost, and preferably 4 or less from the same viewpoint. Specifically, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group and the like are exemplified.

In the general formula (2), n indicates the number of moles of alkylene oxide added. n is preferably 3 or more from the viewpoint of dispersibility, availability and cost, and preferably 40 or less from the same viewpoint.

The combination of A and n in the general formula (2) is preferably a linear or branched divalent saturated hydrocarbon in which A has 2 or more and 3 or less carbon atoms from the viewpoint of coatability, surface hardness, and transparency. Based on this, it is a combination of numbers in which n is 0 or more and 20 or less.

Specific examples of the modifying group represented by the general formula (1) include ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group, decyl group, dodecyl group and tetradecyl group. , Hexadecyl group, octadecyl group, isooctadecyl group, icosyl group, hydroxyethyl group, methylhydroxyethyl group, ethylhydroxyethyl group, propylhydroxyethyl group, butylhydroxyethyl group, pentylhydroxyethyl group, hexylhydroxyethyl group, heptylhydroxy Ethyl group, octyl hydroxyethyl group, 2-ethylhexyl hydroxyethyl group, nonyl hydroxyethyl group, decyl hydroxyethyl group, undecyl hydroxyethyl group, dodecyl hydroxyethyl group, hexadecyl hydroxyethyl group, octadecyl hydroxyethyl group, isooctadecyl hydroxy Examples thereof include an ethyl group, an icosyl hydroxyethyl group, and a triactyl hydroxyethyl group.

Specific examples of the modifying group represented by the general formula (2) include, for example, 3-butoxy-2-hydroxy-propyl group, 3-hexitoxyethylene oxide-2-hydroxy-propyl group, and 3-hepoxy-2-hydroxy. -Propyl group, 3-octoxyethylene oxide-2-hydroxy-propyl group, 3-octoxy-2-hydroxy-propyl group, 6-ethyl-3-hexitoxy-2-hydroxy-propyl group, 6-ethyl-3-hexyl Toxyethylene Oxide-2-Hydroxy-Propyl Group, 3-Detoxyethylene Oxide-2-Hydroxy-Propyl Group, 3-Detoxy-2-Hydroxy-Propyl Group, 3-Undetoxieethylene Oxide-2-Hydroxy-Propyl Group, 3-Undetoxy -2-Hydroxy-propyl group, 3-dodetoxyethylene oxide-2-hydroxy-propyl group, 3-dodetoxi-2-hydroxy-propyl group, 3-hexadetoxyethylene oxide-2-hydroxy-propyl group, 3-hexadetoxy Examples thereof include -2-hydroxy-propyl group, 3-octadetoxyethylene oxide-2-hydroxy-propyl group, 3-octadetoxy-2-hydroxy-propyl group, 3-o-methylphenoxy-2-hydroxy-propyl group and the like. .. The number of moles of alkylene oxide added may be 0 or more and 50 or less. For example, among the above-mentioned substituents having an oxyalkylene group such as ethylene oxide, substituents having 10, 12, 13, and 20 moles of added moles are exemplified. Will be done.

(Molar degree of substitution (MS))
In the modified cellulose fiber (B) of Embodiment 1, the molar amount (molar substitution degree: MS) into which a modifying group is introduced for 1 mol of an anhydrous glucose unit of cellulose is not unconditionally limited depending on the type of modifying group, but is coated. From the viewpoint of workability, surface hardness, and transparency, it is preferably 0.0001 mol or more, more preferably 0.01 mol or more, still more preferably 0.1 mol or more, and has a cellulose type I crystal structure. However, from the viewpoint of coatability, surface hardness, and transparency, it is preferably 1.5 mol or less, more preferably 1.2 mol or less, and further preferably 1 mol or less. Here, when the bound modifying group is composed of a plurality of types of modifying groups, the MS of the bound modifying group is the sum of the MS of each modifying group. In the present specification, the MS of the modifying group in the modified cellulose fiber (B) can be measured according to the method described in Examples described later.

<Manufacturing method of modified cellulose fiber (B)>
In the modified cellulose fiber (B) in the present invention, as described above, a modifying group, preferably a hydrocarbon group which may have the above-mentioned modifying group, is bonded to the cellulose fiber via an ether bond. , The introduction of the modifying group can be carried out according to a known method without particular limitation. Hereinafter, a specific example of the method for producing the modified cellulose fiber (B) of the first aspect will be described.

(Method for Producing Modified Cellulose Fiber (B) of Aspect 1)
As a specific example of the method for producing the modified cellulose fiber (B) of the first aspect, there is an embodiment in which a specific compound is reacted with the raw material cellulose fiber in the presence of a base.

Further, from the viewpoint of reducing the number of manufacturing steps, the cellulose fiber finely divided in advance may be used as the raw material cellulose fiber, and the average fiber diameter in that case is preferably 1 nm or more from the viewpoint of availability and cost. Although the upper limit is not particularly set, it is preferably 500 nm or less from the viewpoint of handleability.

(base)
The base is not particularly limited, but from the viewpoint of advancing the etherification reaction, alkali metal hydroxides, alkaline earth metal hydroxides, primary to tertiary amines, quaternary ammonium salts, imidazole and its derivatives, and pyridines. And a derivative thereof, and one or more selected from the group consisting of alkoxides are preferable. Specifically, the bases described in paragraphs 0053 to 0058 of JP-A-2017-053077 can be mentioned.

The amount of the base is preferably 0.01 equivalent or more from the viewpoint of advancing the etherification reaction with respect to the anhydrous glucose unit of the raw material cellulose fiber, and is preferably 10 equivalent or less from the viewpoint of production cost.

The raw material cellulose fiber and the base may be mixed in the presence of a solvent. The solvent is not particularly limited, and is, for example, water, isopropanol, t-butanol, dimethylformamide, toluene, methyl isobutyl ketone, acetonitrile, dimethyl sulfoxide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, hexane, and the like. Included are 1,4-dioxane, and mixtures thereof.

The temperature and time of the mixing of the raw material cellulose fibers and the base are not particularly limited as long as they can be mixed uniformly.

Next, a modifying compound (also referred to as an "ethering agent" in the present specification), preferably a hydrocarbon group which may have a substituent, is added to the mixture of the raw material cellulose fiber and the base obtained above. A compound for introduction is added to react the raw material cellulose fiber with the compound. As such a compound, it is preferable to use a compound having a cyclic structural group having reactivity, and it is more preferable to use a compound having an epoxy group.

Examples of the compound to which the modifying group represented by the general formula (1) can be bonded via an ether bond include the oxide alkylene compounds described in paragraphs 0079 to 0084 of JP-A-2017-053077.

Examples of the compound to which the modifying group represented by the general formula (2) can be bonded via an ether bond include the glycidyl ether compounds described in paragraphs 805 to 0091 of JP-A-2017-053077.

The amount of the modifying compound can be determined by the desired introduction rate of the modifying group in the obtained modified cellulose fiber (B), but is preferable with respect to the anhydrous glucose unit of the raw material cellulose fiber from the viewpoint of reactivity. Is 0.01 equivalents or more, and is preferably 10 equivalents or less from the viewpoint of manufacturing cost.

(Aetherization reaction)
The etherification reaction between the compound and the raw material cellulose fiber can be carried out by mixing both in the presence of a solvent. The solvent is not particularly limited, and a solvent exemplified as being usable when the base is present can be used. For details of the etherification reaction, the description in paragraphs 0070 to 0075 of JP-A-2017-053077 can be referred to.

The modified cellulose fiber (B) of the first aspect thus obtained may be subjected to a known miniaturization treatment, for example, a treatment using a high-pressure homogenizer or the like in an organic solvent.

Regarding both of the above-mentioned modified cellulose fibers (A) and (B), the modified cellulose fiber can be used in the state of a dispersion liquid, or the solvent is removed from the dispersion liquid by a drying treatment or the like. , Dried powdered modified cellulose fibers can also be obtained and used. Here, the “powder” is a powder in which modified cellulose fibers are aggregated, and does not mean cellulose particles.

Examples of the powdered modified cellulose fiber include a dried product obtained by drying the dispersion liquid of the cellulose fiber as it is; a powder obtained by mechanically treating the dried product; a known spray-drying method for the dispersion liquid of the cellulose fiber. The dispersion liquid of the cellulose fiber is pulverized by a known freeze-drying method and the like. The spray-drying method is a method in which the dispersion liquid of the cellulose fibers is sprayed in the air and dried.

<Characteristics of modified cellulose fiber>
The modified cellulose fiber has a cellulose I-type crystal structure due to the fact that natural cellulose fiber is used as a raw material thereof. The cellulose type I is the crystal form of natural cellulose, and the cellulose type I crystallization degree means the ratio of the amount of the cellulose type I crystal region to the whole cellulose. The presence or absence of the cellulose I-type crystal structure can be determined by the peak at 2θ = 22.6 ° in the X-ray diffraction measurement.

From the viewpoint of surface hardness, the degree of cellulose I-type crystallinity of the modified cellulose fiber is preferably 30% or more, more preferably 35% or more, still more preferably 40% or more, still more preferably 45% or more. Further, from the viewpoint of the cost of the cellulose raw material used, it is preferably 95% or less, more preferably 90% or less, still more preferably 85% or less, still more preferably 80% or less. In this specification, the degree of cellulose I-type crystallinity in cellulose fibers, modified cellulose fibers, etc. is specifically measured by the method described in Examples described later.

The average fiber length of the modified cellulose fiber is preferably 10 nm or more, more preferably 20 nm or more, still more preferably 50 nm or more from the viewpoint of production efficiency, while 500 nm or less, preferably 400 nm from the viewpoint of coatability. Below, it is more preferably 300 nm or less, further preferably 250 nm or less, still more preferably 200 nm or less, still more preferably 150 nm or less. The average fiber length of the modified cellulose fiber can be measured by the method described in Examples described later.

The average fiber diameter of the modified cellulose fiber is preferably 1 nm or more, more preferably 2 nm or more, still more preferably 3 nm or more from the viewpoint of production efficiency, and preferably 30 nm or less, more preferably 30 nm or less from the viewpoint of coatability. It is 10 nm or less, more preferably 5 nm or less. The average fiber diameter of the modified cellulose fiber can be measured by the method described in Examples described later.

The average aspect ratio of the modified cellulose fiber is preferably 1 or more, more preferably 5 or more, still more preferably 8 or more from the viewpoint of production efficiency, and preferably 150 or less, more preferably more preferably from the viewpoint of coatability. It is 100 or less, more preferably 80 or less, still more preferably 60 or less, still more preferably 50 or less. The average aspect ratio of the modified cellulose fiber can be measured by the method described in Examples described later.

Examples of the method for setting the average aspect ratio of the modified cellulose fiber to 150 or less include a method of refining the modified cellulose fiber whose short fiber length is within the range of 1 μm or more and 1000 μm or less. .. The average fiber length of such short fiber cellulose fibers is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, still more preferably 25 μm or more, and preferably 1000 μm or less, more preferably 800 μm or less. It is more preferably 500 μm or less, still more preferably 400 μm or less. The average fiber diameter is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 15 μm or more, and preferably 300 μm or less, more preferably 100 μm or less, still more preferably 60 μm or less.

A known method can be used as the short fiber treatment, and the target cellulose fiber is subjected to alkaline hydrolysis treatment, acid hydrolysis treatment, hydrogen peroxide treatment, ultraviolet treatment, electron beam treatment, hot water decomposition treatment, mechanical treatment, etc. It can be shortened by enzymatic treatment. The modified cellulose fiber to be subjected to the miniaturization treatment may be shortened before the introduction of the above-mentioned modifying group or ionic group, or may be shortened after the introduction. For example, there is a production mode in which an ionic group is introduced into the raw material cellulose fiber, then a staple treatment is performed, and then a modifying group is introduced, and the obtained staple-modified cellulose fiber is miniaturized.

As a device that can be used in the miniaturization process, a known disperser can be mentioned as a suitable device. For example, a stirrer equipped with a stirrer, a breaker, a beater, a low pressure homogenizer, a high pressure homogenizer, a grinder, a cutter mill, a ball mill, a jet mill, a roll mill, a short shaft kneader, a twin shaft kneader, a short shaft extruder, etc. A twin-screw extruder, an ultrasonic stirrer, a household juicer mixer, or the like can be used. The operating conditions of the device may be appropriately set with reference to the attached instruction manual.

The amount of the modified cellulose fiber in the transparent coating agent of the present invention is preferably 0.01% by mass or more in terms of the blending amount and in terms of cellulose (excluding modifying groups) from the viewpoint of improving hardness. It is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and on the other hand, from the viewpoint of maintaining transparency. It is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, still more preferably 10% by mass or less, still more preferably 7% by mass or less, still more preferably 5% by mass or less, still more preferably. It is 3% by mass or less.

The mass ratio of the total amount of the modified cellulose fiber / resin precursor or resin in the transparent coating agent of the present invention is converted into a compounding amount and converted into cellulose (excluding modifying groups) from the viewpoint of improving hardness. , Preferably 0.01 / 100 or more, more preferably 0.05 / 100 or more, still more preferably 0.1 / 100 or more, still more preferably 0.3 / 100 or more, still more preferably 0.5 / 100 or more, It is more preferably 1/100 or more, while it is preferably 30/100 or less, more preferably 20/100 or less, still more preferably 15/100 or less, still more preferably 10/100 or less, from the viewpoint of maintaining transparency. It is more preferably 7/100 or less, still more preferably 5/100 or less, still more preferably 4/100 or less, still more preferably 3/100 or less.

(Solvent or dispersion medium)
In the transparent coating agent of the present invention, a solvent or a dispersion medium can be further blended. Examples of the solvent or dispersion medium that can be blended include water, ethyl acetate, methyl methacrylate, methanol, ethanol, isopropanol, N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N, N-dimethylacetamide, and the like. Examples thereof include tetrahydrofuran (THF), propylene glycol monomethyl ether, diester of succinic acid and triethylene glycol monomethyl ether, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dichloromethane, chloroform, toluene, acetic acid and the like. The seeds can be used alone or in combination of two or more. When a solvent or a dispersion medium is used, the amount thereof is, for example, preferably 30 parts by mass or more, more preferably 50 parts by mass or more, still more preferably 70 parts by mass or more with respect to 100 parts by mass of the resin precursor or the resin. On the other hand, it is preferably 5000 parts by mass or less, more preferably 1000 parts by mass or less, and further preferably 500 parts by mass or less.

(wax)
In the transparent coating agent of the present invention, wax can be further blended. Examples of the wax that can be blended include synthetic wax, plant-derived wax, animal-derived wax, and petroleum-derived wax such as paraffin wax.
Examples of the synthesized wax include polyolefin waxes such as polyethylene, which are liquid at 25 ° C.

The transparent coating agent of the present invention can optionally further contain additives such as stabilizers, dehydrating agents, leveling agents, thickeners and ultraviolet absorbers. 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. Further, it can also be used as a paint by adding various pigments, colorants such as dyes, carbon black, charge modifiers, aluminum paste, talc, glass frit, metal powder and the like to the transparent coating agent of the present invention.

Since the transparent coating agent of the present invention has excellent coatability of modified cellulose fibers, it is a transparent coating agent for transparent materials such as glass, optical displays, and eyeglass lenses, clear coating for the surface of automobile bodies, and paper-based materials. It can be suitably used for wood materials, packaging materials such as plastic films, overcoating agents (varnishes) such as labels, and the like. The transparent coating agent before coating is liquid, emulsion or solid (for example, pellet or powder) at room temperature (25 ° C.). In the case of a solid state, an appropriate medium can be added to make a paste, a solution, or a dispersion. In addition, it can be heated to form a fluid when used.

In addition, additives other than the above can be appropriately selected as the components of the transparent coating agent of the present invention according to the substrate to be coated and the intended use, as long as the effects of the present invention are not impaired.

The base material to which the transparent coating agent of the present invention is applied includes metals such as iron, stainless steel, aluminum, alumite, and duralmine; metal oxides such as iron oxide, ferrite, alumina, and zinc oxide; mortar, Inorganic base materials such as slate, concrete, glass, and ceramic; wood, plywood; paper-based materials such as thick paper, paperboard, wrapping paper, and coated paper; and resins such as thermosetting resin, thermoplastic resin, and FRP are exemplified. Examples of the shape of the base material are plate-like, sheet-like, block-like, film-like, particle-like, and powder-like.

[Manufacturing method of transparent coating agent]
The transparent coating agent of the present invention can be produced by mixing each of the above components. The method of mixing each component is not particularly limited, and examples thereof include a method using a stirrer, an ultrasonic homogenizer, a high-pressure homogenizer, and the like.

[How to apply a transparent coating agent]
The transparent coating agent of the present invention can be applied by a method of applying using a bar coater, an applicator, a spin coater or the like, or a known method using brush coating, hand coating, spraying, dip coating or the like. .. Further, after coating, it can be cured by using a UV irradiator or the like.

[Transparent coating film]
The film (transparent coating film) after coating is transparent so as not to impair the appearance of the base material, and the Haze value is preferably 50 or less, more preferably 10 or less, and further preferably 3 or less. The dry film thickness of the coating film is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, and preferably 2000 μm or less from the viewpoint of transparency. , More preferably 1000 μm or less, still more preferably 500 μm or less. The surface hardness of the coating film is preferably 6B or more, more preferably HB or more, still more preferably H or more, still more preferably 2H or more as the pencil hardness from the viewpoint of protecting the base material. The upper limit value can be, for example, 10H or less. The arithmetic mean roughness of the surface of the coating film is preferably 50 μm or less, more preferably 10 μm or less, still more preferably 6 μm or less, still more preferably 3 μm or less, from the viewpoint of good appearance. The lower limit value can be, for example, 0.3 μm or more. The specific puncture strength of the coating film cannot be unequivocally determined because it depends on the resin type used and the coating thickness, but from the viewpoint of protecting the base material, for example, it is preferably 20 N / mm or more, more preferably 25 N / mm or more. More preferably, it is 30 N / mm or more. The upper limit is not particularly limited, but may be, for example, 1000 N / mm or less. The Haze value, surface hardness, arithmetic mean roughness of the surface, and specific puncture strength of the coating film can be measured by the methods described in Examples described later.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The "normal pressure" indicates 101.3 kPa, and the "normal temperature" indicates 25 ° C.

[Average fiber diameter, average fiber length and average aspect ratio of anion-modified cellulose fibers and modified cellulose fibers]
Deionized water or DMF is added to the cellulose fiber to be measured to prepare a dispersion having a content of 0.0001% by mass. Atomic force microscope (AFM) (Nanoscope II Tappingmode AFM, manufactured by Digital instrument, Nanoscope II Tappingmode AFM; probe manufactured by Nanosensors, Point Probe (AFM) Using NCH)), the fiber height (difference in height between the presence and absence of fibers) of the cellulose fibers in the observation sample is measured. At that time, in a microscope image in which the cellulose fibers can be confirmed, 100 cellulose fibers are extracted, and the average fiber diameter is calculated from the fiber heights thereof. The average fiber length is calculated from the distance in the fiber direction. The average aspect ratio is calculated from the average fiber length / average fiber diameter. The height analyzed in the image by AFM can be regarded as the fiber diameter.

[Average fiber diameter and average fiber length of raw material cellulose fiber]
Deionized water is added to the cellulose fibers to be measured to prepare a dispersion having a content of 0.01% by mass. Using a wet dispersion type image analysis particle size distribution meter (manufactured by Jasco International, trade name: IF-3200), the dispersion is used for front lens: 2x, telecentric zoom lens: 1x, image resolution: 0.835 μm / pixel. , Syringe inner diameter: 6515 μm, spacer thickness: 500 μm, image recognition mode: ghost, threshold value: 8, analytical sample volume: 1 mL, sampling: 15%. 100 cellulose fibers are measured, and the average ISO fiber diameter thereof is used as the average fiber diameter, and the average ISO fiber length is calculated as the average fiber length.

[Solid content in dispersion]
Measure using a halogen moisture meter (manufactured by Shimadzu Corporation; trade name "MOC-120H"). Measurement is performed every 30 seconds at a constant temperature of 150 ° C. for 1 g of the sample, and the value at which the mass loss is 0.1% or less of the initial amount of the sample is defined as the solid content.

[Anionic group content of anionic-modified cellulose fibers and modified cellulose fibers]
Take the cellulose fiber to be measured with a dry mass of 0.5 g in a beaker, add deionized water or a mixed solvent of methanol / water = 2/1 (volume ratio) to make a total of 55 mL, and add 5 mL of 0.01 M sodium chloride aqueous solution to this. To prepare a dispersion. The dispersion is stirred until the cellulose fibers to be measured are sufficiently dispersed. Add 0.1 M hydrochloric acid to this dispersion to adjust the pH to 2.5 to 3, and use an automatic titrator (manufactured by Toa DKK, trade name "AUT-701") to add a 0.05 M aqueous sodium hydroxide solution. Then, the solution is added dropwise to the dispersion under the condition of a waiting time of 60 seconds, and the electric conductivity and pH values are measured every minute. Continue the measurement until the pH reaches about 11, and obtain an electric conductivity curve. From this conductivity curve, the quantification of sodium hydroxide titration is obtained, and the anionic group content of the cellulose fiber to be measured is calculated by the following formula.
Anionic group content (mmol / g) = [Titration of aqueous sodium hydroxide solution (mL) x concentration of aqueous sodium hydroxide solution (0.05 M)] / [Mass of cellulose fiber to be measured (0.5 g)]

[Average bond amount and introduction rate of modifying group of modified cellulose fiber (A)]
The average binding amount of the modifying group is obtained by the following IR measurement method, and the average binding amount and the introduction rate are calculated by the following formula. Specifically, the IR measurement is performed by measuring the infrared absorption spectrum of the dried modified cellulose fiber by the ATR method using an infrared absorption spectroscope (IR) (Nicolet 6700 manufactured by Thermo Fisher Scientific Co., Ltd.). , The average binding amount and introduction rate of the modifying group are calculated by the formulas A and B. The following shows the case where the anionic group is a carboxy group, that is, the case of an oxidized cellulose fiber. The following "peak intensity of 1720 cm ^-1 " is the peak intensity derived from the carbonyl group. In the case of an anionic group other than the carboxy group, the wave number value may be appropriately changed to calculate the average bond amount and introduction rate of the modifying group.
<Formula A-1 (in the case of ionic bond)>
Average bond amount of modifying group (mmol / g) = a × (bc) ÷ b
a: Carboxy group content of cellulose oxide fiber (mmol / g)
b: Peak intensity of 1720 cm ^{-1 of oxidized cellulose fiber c: Peak intensity of 1720 cm -1 of} modified cellulose fiber <Formula A-2 (in the case of amide bond)>
Average bond amount of modifying group (mmol / g) = de
d: Carboxy group content of cellulose oxide fiber (mmol / g)
e: Carboxy group content of modified cellulose fiber (mmol / g)
<Equation B>
Introductory rate of modifying group (mol%) = 100 × f / g
f: Average bond amount of modifying group (mmol / g)
g: Carboxy group content of cellulose oxide fiber (mmol / g)

[Cellulose fiber (converted amount) in modified cellulose fiber (A)]
The amount of cellulose (converted amount) in the modified cellulose fiber is the amount of cellulose in the modified cellulose fiber excluding the modifying group. In the modified cellulose fiber in the present invention, the formula amount of the modifying group may be considerably larger (for example, than the molecular weight of glucose). When is appropriate, the amount of cellulose constituting the modified cellulose fiber (converted amount) is displayed instead of the amount of the modified cellulose fiber.
The cellulose fiber (converted amount) in the modified cellulose fiber is measured by the following method.

(1) When one kind of "modifying compound" is added The amount of cellulose fibers (converted amount) is calculated by the following formula E.
<Equation E>
Cellulose fiber amount (converted amount) (g) = mass of modified cellulose fiber (g) / [1 + molecular weight of modifying compound (g / mol) × bonding amount of modifying group (mmol / g) × 0.001]
(2) When there are two or more types of "modifying compounds" to be added The amount of cellulose fibers in consideration of the molar ratio of each compound (that is, the molar ratio when the total molar amount of the added compounds is 1) Calculate (converted amount).

When the bonding mode between the cellulose fiber and the modifying compound is an ionic bond, in the above formula, the "molecular weight of the modifying compound" means that the modifying compound is a primary amine, a secondary amine or a tertiary amine. When it is an amine, it means "the molecular weight of the entire modifying compound including the copolymerization part", and when the compound having a modifying group is a quaternary ammonium compound or a phosphonium compound, "(for modification including the copolymerization part)". Molecular weight of the whole compound)-(Molecular weight of anionic component) ”.
On the other hand, when the bonding mode between the cellulose fiber and the modifying compound is an amide bond, the "molecular weight of the modifying compound" in the above formula means that the modifying compound is a primary amine or a secondary amine. "(Molecular weight of the entire compound having a modifying group including the copolymerization portion) -18".

[Introduction amount and introduction mass of modifying group of modified cellulose fiber (B)]
Analytical Chemistry, Vol.51, No.13,2172 (1979), "15th Amendment" It was calculated according to the Zeisel method, which is known as a method for analyzing the average number of moles of alkoxy groups of cellulose ether described in "Japanese Pharmacy (section of analysis method for hydroxypropyl cellulose)". The procedure is shown below.

(I) 0.1 g of n-octadecane was added to a 200 mL volumetric flask, and the volumetric flask was adjusted to the marked line with hexane to prepare an internal standard solution.
(Ii) 100 mg of purified and dried modified cellulose fiber and 100 mg of adipic acid were precisely weighed in a 10 mL vial, and 2 mL of hydrogen iodide was added and sealed.
(Iii) The mixture in the vial was heated with a block heater at 160 ° C. for 1 hour while stirring with a stirrer tip.
(Iv) After heating, 3 mL of the internal standard solution and 3 mL of diethyl ether were sequentially injected into the vial, and the mixture was stirred at room temperature for 1 minute.
(V) The upper layer (diethyl ether layer) of the mixture separated into two phases in the vial was analyzed by gas chromatography (manufactured by Shimadzu Corporation, GC2010Plus), and the etherifying agent was quantified.
(Vi) Separately, instead of the modified cellulose fiber, 5 mg, 10 mg, and 15 mg of the etherifying agent used for the modification were used, and the analysis was performed in the same manner as in (i) to (v) above. A calibration curve of the etherifying agent was prepared.

The analysis conditions are as follows.
Column: Agilent Technologies DB-5 (12m, 0.2mm x 0.33μm)
Column temperature: 100 ° C → 10 ° C / min → 280 ° C (10min Hold)
Injector temperature: 300 ° C, detector temperature: 300 ° C, driving amount: 1 μL
The introduced mass (mass%) of the modifying group in the modified cellulose fiber was calculated from the prepared calibration curve and the detected amount of the etherifying agent used.

Then, from the introduced mass of the obtained substituents, the degree of molar substitution (MS) was calculated using the following formulas (1) to (3).
(When only one type of substituent is introduced)
MS = (W / Mw) / ((100-W) /162.14) (1)
W: Introduced mass (% by mass) of substituent in modified cellulose
Mw: Molecular weight of the introduced etherifying agent (g / mol)
(When two types of substituents are introduced)
MS ₁ = (W ₁ / Mw ₁ ) / ((100-W ₁ -W ₂ ) /162.14) (2)
MS ₂ = (W ₂ / Mw ₂ ) / ((100-W ₁ -W ₂ ) /162.14) (3)
MS ₁ : Molar degree of substitution of the first type of substituent
MS ₂ : Molar degree of substitution of the second type of substituent
W ₁ : Introduction mass (mass%) of the first type of substituent in the modified cellulose
W ₂ : Introduced mass (% by mass) of the second type of substituent in the modified cellulose
Mw ₁ : Molecular weight (g / mol) of the first type of etherifying agent introduced
Mw ₂ : Molecular weight (g / mol) of the second type of etherifying agent introduced

[Cellulose fiber (converted amount) in modified cellulose fiber (B)]
(When only one type of substituent is introduced)
Cellulose fiber (converted amount) (g) = mass (g) of modified cellulose fiber (B) x 162.14 / (162.14 + Mw ₁ x MS ₁ )
(When two types of substituents are introduced)
Cellulose fiber (converted amount) (g) = mass (g) of modified cellulose fiber (B) x 162.14 / (162.14 + Mw ₁ x MS ₁ + Mw ₂ x MS ₂ )

[Confirmation of crystal structure in various cellulose fibers]
The crystal structure of various cellulose fibers such as modified cellulose fibers is confirmed by measuring under the following conditions using an X-ray diffractometer (MiniFlexII manufactured by Rigaku Corporation).
The measurement conditions are X-ray source: Cu / Kα-radiation, tube voltage: 30 kv, tube current: 15 mA, measurement range: diffraction angle 2θ = 5 to 45 °, and X-ray scan speed: 10 ° / min. As a sample for measurement, the cellulose fiber to be measured is compressed into pellets having an area of 320 mm ² × thickness of 1 mm. Further, the crystallinity of the cellulose type I crystal structure is calculated by calculating the obtained X-ray diffraction intensity based on the following formula C.

<Formula C>
Cellulose type I crystallinity (%) = [(I _22.6 -I _18.5 ) / I _22.6 ] x 100
[In the formula, I _22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I _18.5 is the amorphous portion (diffraction angle 2θ = 18.5). °) Diffraction intensity is shown. ]

On the other hand, when the crystallinity obtained by the above formula C is 35% or less, from the viewpoint of improving the calculation accuracy, P199-200 of "Wood Science Experiment Manual" (edited by Japan Wood Society; published in April 2000). It is preferable to calculate based on the following formula D according to the description of.
Therefore, when the crystallinity obtained by the above formula C is 35% or less, the value calculated based on the following formula D can be used as the crystallinity.

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

[Preparation of anion-modified cellulose fibers]
Preparation Example 1
Bleached kraft pulp of coniferous tree (manufactured by West Freather Co., Ltd., trade name: Hinton) was used as a natural cellulose fiber. As the TEMPO, a commercially available product (ALDRICH, Free radical, 98% by mass) was used. As the sodium hypochlorite, a commercially available product (10.5% by mass aqueous solution manufactured by Wako Pure Chemical Industries, Ltd.) was used. As sodium bromide, a commercially available product (manufactured by Wako Pure Chemical Industries, Ltd.) was used.

First, 10 g of the bleached kraft pulp fiber is sufficiently stirred with 990 g of deionized water, and then 0.13 g of TEMPO, 1.3 g of sodium bromide, and 10.5% by mass of sodium hypochlorite are mixed with the 10 g of the pulp fiber. 27 g of the aqueous solution was added in this order. Using a pH stat titration with an automatic titrator (manufactured by DKK-TOA CORPORATION, trade name: AUT-701), a 0.5 M sodium hydroxide aqueous solution was added dropwise to maintain the pH at 10.5. After the reaction was carried out at a stirring speed of 200 rpm for 120 minutes (20 ° C.), the dropping of sodium hydroxide was stopped to obtain anion-modified cellulose fibers.

After neutralizing the obtained anion-modified cellulose fiber with 0.01 M hydrochloric acid, the conductivity of the filtrate is measured by a compact electric conductivity meter (LAQUAtwin EC-33B, manufactured by Horiba, Ltd.) using deionized water. Was thoroughly washed until the temperature became 200 μs / cm or less, and then dehydration treatment was performed. The carboxy group content of the anion-modified cellulose fiber was 1.5 mmol / g, the average fiber diameter was 61 μm, and the average fiber length was 952 μm.

Preparation Example 2
In a vial equipped with a magnetic stirrer and a stirrer, 7.2 g of the anion-modified cellulose fiber obtained in Preparation Example 1 was charged in an absolute dry mass, and deionized water was added until the mass of the treatment liquid reached 360 g. The treatment liquid was stirred at 95 ° C. for 24 hours to obtain anion-modified cellulose fibers. The carboxy group content of the anion-modified cellulose fiber was 1.3 mmol / g, the average fiber diameter was 40 μm, and the average fiber length was 93 μm.

Example 1
In a beaker equipped with a magnetic stirrer and a stirrer, 1.40 g (solid content concentration 29.3% by mass, cellulose fiber amount 0.41 g) and DMF 10 mass times (solid content concentration 29.3 mass%, cellulose fiber amount 0.41 g) finally obtained in Preparation Example 2 (solid content concentration 29.3 mass%, cellulose fiber amount 0.41 g). 14.0 g) was added and the mixture was stirred for 30 minutes. Then, it was centrifuged at 5 ° C. under the condition of 10000 × g for 1 minute. The same operation was repeated on the insoluble residue to obtain DMF-substituted anion-modified cellulose fibers. Subsequently, DMF was added so that the total amount with the insoluble residue was 40 g. The mixture was reacted at room temperature (25 ° C.) for 30 minutes, and then subjected to 5-pass dispersion treatment at 150 MPa using a high-pressure homogenizer (manufactured by Yoshida Machinery Co., Ltd., trade name: Nanovaita L-ES) to refine anion modification. A DMF dispersion of cellulose fibers (cellulose fiber concentration 1%, total solid content concentration 1.%) was obtained. 2 g of the obtained finely divided dispersion of anion-modified cellulose fibers (that is, the amount of cellulose fibers 0.02 g) and 2 g of dipentaerythritol hexamethacrylate (light acrylate DPE-6A manufactured by Kyoeisha Chemical Co., Ltd.) were added. The mixture was stirred and mixed at 2000 rpm for 2 minutes using an automatic revolution type stirrer (manufactured by Shinky Co., Ltd., Awatori Rentaro). Subsequently, 0.06 g of 1-hydroxycyclohexylphenyl ketone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added as a curing agent, stirred at 2000 rpm for 1 minute using an automatic revolution type stirrer, defoamed at 2200 rpm for 1 minute, and solidified. A coating liquid of about 50% was obtained. The coating liquid was obtained as a highly transparent liquid composition. A nylon film (thickness of about 20 μm) is coated with a bar coater to a thickness of about 20 μm, dried at 80 ° C. and normal pressure for 1 minute, and then UV irradiator (EYE INVERTOR, manufactured by EYE GRAPHICS). A coating film was obtained by passing 2 passes at a speed of 4 kW, a height of 150 mm, and a speed of 246 cm / min with GRANDAGE (4 kW). The irradiance was about 24 mW / cm ² , and the irradiation amount was about 580 mJ / cm ² .

Example 2
In a beaker equipped with a magnetic stirrer and a stirrer, 1.40 g (solid content concentration 29.3% by mass, cellulose fiber amount 0.41 g) and methanol 10 times by mass (14) of the anion-modified cellulose fiber obtained in Preparation Example 2 were added. .0 g) was added and the mixture was stirred for 30 minutes. Then, it was centrifuged at 5 ° C. under the condition of 10000 × g for 1 minute. The same operation was repeated for the insoluble residue to obtain 0.96 g of anion-modified cellulose fibers (solid content concentration 41.8% by mass, cellulose fiber amount 0.40 g) substituted with methanol. EOPO monoamine (Jeffamine M2070, EO / PO (molar ratio) = 31/10, manufactured by Huntsman, USA, EO / PO (molar ratio) = 31/10) was added to the obtained anion-modified cellulose fiber with respect to 100 parts by mass of the anion-modified cellulose fiber. After adding 38.9 g of methanol in an amount corresponding to 26 parts by mass and reacting the mixture at room temperature (25 ° C.) for 30 minutes, a high-pressure homogenizer (manufactured by Yoshida Kikai Co., Ltd., trade name: NanoVita L-ES) was used. , A methanol dispersion of modified cellulose fibers (cellulose fiber concentration 1%, total solid content concentration 1) in which EOPO monoamine is linked to anion-modified cellulose fibers that have been subjected to 3-pass dispersion treatment at 150 MPa via ionic bonds. .26%) was obtained. 2 g of the obtained modified cellulose fiber dispersion (that is, the amount of cellulose fiber 0.02 g) and 2 g of dipentaerythritol hexamethacrylate (light acrylate DPE-6A manufactured by Kyoeisha Chemical Co., Ltd.) are automatically revolved and stirred. Using a machine (manufactured by Shinky Co., Ltd., Awatori Rentaro), the mixture was stirred at 2000 rpm for 2 minutes and mixed. Subsequently, 0.06 g of 1-hydroxycyclohexylphenyl ketone (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a curing agent, stirred at 2000 rpm for 1 minute using an automatic revolution type stirrer, defoamed at 2200 rpm for 1 minute, and solidified. A coating liquid of about 50% was obtained. The coating liquid was obtained as a highly transparent liquid composition. A nylon film is coated with a bar coater to a thickness of about 20 μm, dried at 80 ° C. and normal pressure for 1 minute, and then subjected to a UV irradiator at a speed of 4 kW, a height of 150 mm, and a speed of 246 cm / min. A coating film was obtained by passing 2 passes. The irradiance was about 24 mW / cm ² , and the irradiation amount was about 580 mJ / cm ² .

Example 3
A coating film was obtained in the same manner as in Example 2 except that the amount of EOPO monoamine added was changed to an amount corresponding to 78 parts by mass with respect to 100 parts by mass of the anion-modified cellulose fiber.

Example 4
6 g of a dispersion of modified cellulose fibers (that is, a cellulose fiber amount of 0.06 g) obtained by the same method as in Example 3 and dipentaerythritol hexametherlate (Light Acrylate DPE-6A manufactured by Kyoeisha Chemical Co., Ltd.). 2 g and 2 g were stirred and mixed at 2000 rpm for 2 minutes using an automatic revolution type stirrer (manufactured by Shinky Co., Ltd., Awatori Rentaro). Then, about 4 g of methanol was removed using an evaporator. Subsequently, 0.06 g of 1-hydroxycyclohexylphenyl ketone (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a curing agent, stirred at 2000 rpm for 2 minutes using an automatic revolution type stirrer, defoamed at 2200 rpm for 1 minute, and solidified. A coating liquid of about 50% was obtained. The coating liquid was obtained as a highly transparent liquid composition. A nylon film is coated with a bar coater to a thickness of about 20 μm, dried at 80 ° C. and normal pressure for 1 minute, and then subjected to a UV irradiator at a speed of 4 kW, a height of 150 mm, and a speed of 246 cm / min. A coating film was obtained by passing 2 passes. The irradiance was about 24 mW / cm ² , and the irradiation amount was about 580 mJ / cm ² .

Example 5
A coating film was obtained in the same manner as in Example 2 except that the amount of EOPO monoamine added was changed to an amount corresponding to 260 parts by mass with respect to 100 parts by mass of the anion-modified cellulose fiber.

Preparation Example 3
To 1.50 g of the absolutely dried NBKP, 1.60 g (0.28 eq / AGU) of a 6.4 mass% sodium hydroxide aqueous solution was added, and the mixture was uniformly mixed. Next, 2.00 g of butylene oxide (manufactured by Wako Pure Chemical Industries, Ltd., 3 equivalents / AGU) was added as the first etherifying agent, and after sealing, a standing reaction was carried out at 50 ° C. for 7 hours. After the reaction, the mixture was neutralized with acetic acid, thoroughly washed with water and acetone to remove impurities, and vacuum dried at 70 ° C. overnight to obtain a cellulose raw material (MS 0.23 of butylene oxide). ..

Next, 1.60 g (NOOH 0.31 equivalent / AGU) of a 6.4 mass% sodium hydroxide aqueous solution was added to 1.50 g of the obtained cellulose raw material, and the mixture was uniformly mixed. Next, 0.95 g of o-methylphenylglycidyl ether (o-cresylglycidyl ether, o-CRGE) (manufactured by Sigma-Aldrich, 0.7 eq / AGU) was added as a second etherifying agent, and the mixture was sealed. Later, a standing reaction was carried out at 70 ° C. for 24 hours. After the reaction, the mixture was neutralized with acetic acid, thoroughly washed with water and acetone to remove impurities, and vacuum dried at 70 ° C. overnight to obtain modified cellulose fibers (o-methylphenylglycidyl ether). MS 0.32). The average fiber diameter of the obtained modified cellulose was 20 μm, and the average fiber length was 323 μm.

To 1.50 g of the obtained modified cellulose fiber, 0.98 g of hydrogen peroxide (45% aqueous solution), 1.24 g of sodium hydroxide and 13.6 g of water were added, mixed uniformly, and then stirred at 98 ° C. for 12 hours. bottom. Then, impurities were removed by washing thoroughly with water and acetone, respectively, and vacuum drying was performed at 70 ° C. overnight to obtain modified cellulose having a low aspect ratio. The average fiber diameter of the obtained modified cellulose having a low aspect ratio was 18 μm, and the average fiber length was 107 μm.

0.71 g of the obtained modified cellulose having a low aspect ratio (0.5 g as the amount of cellulose without substituents only) was put into 49.5 g of DMF, and in a beaker equipped with a magnetic stirrer and a stirrer. After stirring for 30 minutes, the finely modified cellulose was dispersed in DMF by treating with a high-pressure homogenizer (manufactured by Yoshida Machinery Co., Ltd., trade name: NanoVeta L-ES) 5 times at 150 MPa at room temperature. A body (cellulose fiber concentration 1%, total solid content concentration 1.42%) was obtained.

Example 6
2 g of a dispersion of finely modified cellulose fibers (that is, 0.02 g of cellulose fibers) and 2 g of dipentaerythritol hexamethritol (light acrylate DPE-6A manufactured by Kyoeisha Chemical Co., Ltd.) obtained in Preparation Example 3. And were mixed by stirring at 2000 rpm for 2 minutes using an automatic revolution type stirrer (manufactured by Shinky Co., Ltd., Awatori Rentaro). Subsequently, 0.06 g of 1-hydroxycyclohexylphenyl ketone (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a curing agent, stirred at 2000 rpm for 2 minutes using an automatic revolution type stirrer, defoamed at 2200 rpm for 1 minute, and solidified. A coating liquid of about 50% was obtained. The coating liquid was obtained as a highly transparent liquid composition. A nylon film is coated with a bar coater to a thickness of about 20 μm, dried at 80 ° C. and normal pressure for 2 minutes, and then subjected to a UV irradiator at a speed of 4 kW, a height of 150 mm, and a speed of 246 cm / min. A coating film was obtained by passing 2 passes. The irradiance was about 24 mW / cm ² , and the irradiation amount was about 580 mJ / cm ² .

Comparative Example 1
The same as in Example 2 except that the amount of EOPO monoamine added using the anion-modified cellulose fiber obtained in Preparation Example 1 is changed to an amount corresponding to 78 parts by mass with respect to 100 parts by mass of the anion-modified cellulose fiber. A coating film was obtained by the method.

Comparative Example 2
The same as in Example 2 except that the amount of EOPO monoamine added using the anion-modified cellulose fiber obtained in Preparation Example 1 is changed to an amount corresponding to 300 parts by mass with respect to 100 parts by mass of the anion-modified cellulose fiber. A coating film was obtained by the method.

Comparative Example 3
Using the anion-modified cellulose fiber obtained in Preparation Example 1, the same as in Example 4 except that the amount of EOPO monoamine added is changed to an amount corresponding to 300 parts by mass with respect to 100 parts by mass of the anion-modified cellulose fiber. A coating film was obtained by the method.

Example 7
By performing the same operation as in Example 2 except that the amount of EOPO monoamine used was changed to an amount corresponding to 78 parts by mass with respect to 100 parts by mass of the anion-modified cellulose fiber, EOPO monoamine was mediated by ionic bonding. A methanol dispersion of the linked modified cellulose fibers (cellulose fiber concentration 0.94% by mass, total solid content concentration 1.67% by mass) was obtained. 3.0 g of the obtained modified cellulose fiber dispersion (that is, the amount of cellulose fiber 0.03 g) and 5.0 g of water-based acrylic varnish (Rock water-based varnish H75-0150, manufactured by Rock Paint Co., Ltd.) are mixed and magnetic stirrer. By stirring the varnish overnight, a coating liquid having a solid content of about 30% containing 3 parts by mass of cellulose fibers with respect to 100 parts by mass of the resin component in the varnish was obtained. The coating liquid was obtained as a highly transparent liquid composition. A cellulose-dispersed varnish solution was applied onto the PET film using a bar coater so as to have a thickness of 150 μm, and dried in a vacuum at 80 ° C. for 2 hours to obtain a coating film.

Example 8
By performing the same operation as in Example 7 except that the varnish used was changed to a water-based urethane varnish (water-based urethane varnish transparent (clear), manufactured by Asahipen Corporation), the cellulose fiber was subjected to 100 parts by mass of the resin component in the varnish. A coating liquid having a solid content of about 30% and containing 3 parts by mass was obtained. The coating liquid was obtained as a highly transparent liquid composition. A cellulose-dispersed varnish solution was applied onto the PET film using a bar coater so as to have a thickness of 150 μm, and dried in a vacuum at 80 ° C. for 2 hours to obtain a coating film.

Preparation Example 4
Anionic-modified cellulose fibers were obtained by carrying out the same reaction and purification operation as in Preparation Example 1 except that the amount of 10.5% by mass sodium hypochlorite aqueous solution was changed to 24 g. The carboxy group content of the anion-modified cellulose fiber was 1.3 mmol / g, the average fiber diameter was 55 μm, and the average fiber length was 961 μm.

Comparative Example 4
A coating film was obtained in the same manner as in Example 7 except that the anion-modified cellulose fiber obtained in Preparation Example 4 was used.

Comparative Example 5
A coating film was obtained in the same manner as in Example 8 except that the anion-modified cellulose fiber obtained in Preparation Example 4 was used.

Example 9
A coated paper was obtained by performing the same operation as in Example 7 except that the coating target was changed to a photo paper for an inkjet printer (glossy paper) (KJ-G14B4-10N, manufactured by KOKUYO S & T Co., Ltd.).

Example 10
A coated paper was obtained by performing the same operation as in Example 8 except that the object to be coated was changed to the same photo paper for an inkjet printer as in Example 9.

Comparative Example 6
A coated paper was obtained by performing the same operation as in Comparative Example 4 except that the coating target was changed to the same photo paper for an inkjet printer as in Example 9.

Comparative Example 7
A coated paper was obtained by performing the same operation as in Comparative Example 5 except that the coating target was changed to the same photo paper for an inkjet printer as in Example 9.

Example 11
A coated paper was obtained by performing the same operation as in Example 9 except that the EOPO monoamine was not used.

Example 12
A coated paper was obtained by performing the same operation as in Example 10 except that the EOPO monoamine was not used.

Comparative Example 8
The same operation as in Comparative Example 6 was carried out except that EOPO monoamine was not used, but a methanol dispersion of the modified cellulose fiber could not be obtained due to poor dispersion and could not be blended with the water-based acrylic varnish, so that a coated paper was obtained. I couldn't.

Comparative Example 9
The same operation as in Comparative Example 7 was carried out except that EOPO monoamine was not used, but a methanol dispersion of the modified cellulose fiber could not be obtained due to poor dispersion and could not be blended with the aqueous urethane varnish, so that a coated paper was obtained. I couldn't.

[Evaluation of coatability]
The appearance of the surface of the coating film after curing was visually confirmed, and the following evaluations were given. The results are shown in Tables 1, 3-5.
A: The surface of the coating film is smooth with almost no visible roughness.
B: There is a rough feeling on the surface of the coating film that can be visually confirmed.
C: There are cracks and wrinkles on the surface of the coating film that can be visually confirmed.

[Evaluation of transparency]
The Haze value of the cured coating film was measured with a haze meter (HM-150 type manufactured by Murakami Color Technology Research Institute). The lower the Haze value, the more transparent it is. The results are shown in Tables 1 and 3.
In addition, the transparency of the coating film on the coated paper was visually confirmed and evaluated as follows. The results are shown in Tables 4 and 5.
A: The surface of the paper covered with the coating film looks clear through the coating film.
B: The surface of the paper covered with the coating film looks blurry through the coating film.
C: The surface of the paper covered with the coating film is completely invisible through the coating film.

[Evaluation of surface hardness]
The substrate used in Examples 1 to 6 and Comparative Examples 1 to 3 was changed from a nylon film to a PET film (Cosmo Shine 100A4300 manufactured by Panac) to prepare a coating film, respectively.
Evaluation was performed according to JIS K5600-5-4 using a pencil hardness tester (BEVS 1301 Pencil Hardness Tester / 750M). The results are shown in Table 1.
The surface hardness of the films obtained in Examples 7 to 8 and Comparative Examples 4 to 5 was evaluated by the same method. The results are shown in Table 3.

[Measurement of Arithmetic Mean Roughness of Membrane]
The arithmetic mean roughness of the film is measured using a laser microscope (manufactured by KEYENCE, VK-9710) under the following measurement conditions. The measurement conditions are objective lens: 10 times, light intensity: 3%, brightness: 1548, Z pitch: 0.5 μm. The arithmetic mean roughness was measured at 5 points using the built-in image processing software, and the average value was used. The results are shown in Tables 2 to 5.

[Evaluation of water absorption rate]
The coated papers obtained in Examples 9 to 12 and Comparative Examples 6 and 7 were cut into 3 cm × 3 cm, and 5 drops of deionized water was dropped on the surface. After allowing to stand for 5 minutes, the water on the surface was wiped off and the mass of the coated paper piece was measured. The lower the water absorption rate, the higher the water resistance, and it is shown that the suitability as a coating film is excellent. The results are shown in Tables 4 and 5.
The water absorption rate was calculated by the following formula. The water absorption rate of the uncoated glossy paper was 12.4%.
Water absorption rate (%) = (mass of paper piece after wiping off-mass of paper piece before dripping water) / mass of dripping water x 100

[Evaluation of specific puncture strength of coating layer]
The specific puncture strength of the coating layer was evaluated by performing tests on the coated papers obtained in Examples 9 to 12 and Comparative Examples 6 and 7 by the following method. It is shown that the higher the piercing strength, the better the suitability as a coating film. The results are shown in Tables 4 and 5.
In a constant temperature room at 25 ° C, use a SHIMADZU autograph precision universal testing machine (AGS-10kNX) to perform a 5-point puncture test per sample in accordance with JIS Z1717: 2019 General Rules for Food Packaging Plastic Films (below). Therefore, the piercing strength of the coated paper was measured. From the obtained piercing strength, the specific piercing strength of the coating layer was determined using the following formula (I).
Formula (I) Specific piercing strength (N / mm) = piercing strength (N) / (thickness of coated paper (mm) -thickness of coated base paper (mm))
* The thickness of the coated paper and the thickness of the coated base paper are analyzed at 5 points with a thickness gauge, and the average value is used. JIS Z 1717: 2019 General rules for plastic films for food packaging
a) Fix the test piece with a jig, pierce a semi-circular needle with a diameter of 1.0 mm and a tip shape radius of 0.5 mm at a test speed of 50 mm / min, and measure the maximum force (N) until the needle penetrates.
b) The number of test pieces shall be 5 or more, and shall be collected on average over the entire width of the product.
c) If the test result depends on which side of the film penetrates, perform on each side. Reported figures shall be one digit after the decimal point.

As can be seen from Tables 1, 3 to 5, all of the transparent coating agents of Examples were excellent in coatability, and could be used as a coating film in terms of transparency and surface hardness without any problem. Further, in Tables 2, 3 and 4, Example 3 and Comparative Example 1, Example 5 and Comparative Example 2, Example 7 and Comparative Example 4, Example 8 and Comparative Example 5, and Example 9 and Comparative Example. 6. From the comparison between Example 10 and Comparative Example 7, it can be seen that the surface roughness of the substrate coated with the transparent coating agent of Example was low, and a smooth coating film could be formed. The coating films of Examples 11 and 12 in Table 5 were also smooth and could be suitably used as a coating film.
As can be seen from Tables 4 and 5, it can be seen that the transparent coating agent of the example has no problem in water resistance as a varnish applied to paper. Of these, in Examples 11 and 12 using unmodified anion-modified cellulose fibers, the specific puncture strength and water resistance were particularly excellent.

The transparent coating agent of the present invention includes transparent coating agents for transparent materials such as glass, optical displays, and spectacle lenses, clear coatings for the surface of automobile bodies, paper-based materials, wood materials, packaging materials such as plastic films, labels, and the like. It can be suitably used as an overcoat agent (glasses) and the like.

Claims (6)

A transparent coating agent containing a resin precursor or a resin and a modified cellulose fiber, wherein the modified cellulose fiber has an average fiber length of 500 nm or less, and is the following modified cellulose fiber (A) and modified. A transparent coating agent that is one or more selected from the group consisting of cellulose fibers (B).
Modified cellulose fiber (A): Cellulose fiber containing an ionic group, or a modified cellulose fiber formed by binding a modifying group to the ionic group. Modified cellulose fiber (B): A modifying group is added to the hydroxy group of the cellulose fiber. Modified cellulose fiber that is bonded The transparent coating agent according to claim 1, wherein the modified cellulose has an average aspect ratio of 150 or less. The transparent coating agent according to claim 1 or 2, wherein the ionic group of the modified cellulose is a carboxy group. The invention according to any one of claims 1 to 3, wherein the modifying group contains at least one selected from the group consisting of (a) a hydrocarbon group, (b) a silicone chain, and (c) an alkylene oxide chain. Transparent coating agent. The transparent coating agent according to any one of claims 1 to 4, wherein the resin is an acrylic resin. The transparent coating agent according to any one of claims 1 to 5, wherein the haze value of the film coated with the transparent coating agent is 50 or less.