JP7808480B2 - Hard surface treatment agent - Google Patents

Description

The present invention relates to a hard surface treatment agent.

Previously, attempts have been made to prevent dirt from adhering to objects by making them water-repellent. Recently, Slippery Liquid-Infused Porous Surface (SLIPS) has been reported, which impregnates a liquid lubricant into a network structure or a finely textured structure. This allows water and other liquids to slide off with a slighter inclination than with conventional water-repellent technologies. This property is called synovial property.
For example, Patent Document 1 describes a method for forming a water-sliding coating made of one or more types of silicone on the surface of a substrate by applying a dispersion of anionic silica fine particles to the surface of the substrate and then applying a silicone emulsion thereto.

Japanese Patent Application Laid-Open No. 2006-247544

The method described in Patent Document 1 involves complicated processing steps, so there is a need for an agent that can impart synovial properties with simple operations.

The subject of this invention is a hard surface modifier that can easily impart synovial properties.

The present invention relates to the following [1] and [2].
[1] A hard surface treatment agent containing an oil-in-water Pickering emulsion.
[2] The hard surface treatment agent according to [1], which is used as an anti-snow paint, an antifouling paint, an antibacterial paint, a flow resistance reducing agent, or a mold release agent.

By using the hard surface treatment agent provided by the present invention, it is possible to easily produce a film with excellent synovial properties on a hard surface.

FIG. 1 is a schematic diagram of a pressure loss measuring device.

As a result of intensive research conducted by the present inventors to solve the above problems, they discovered that an agent containing an oil-in-water Pickering emulsion can easily provide a film with synovial properties on a hard surface, and thus completed the present invention.
A Pickering emulsion is an emulsion stabilized by solid particles adsorbed at the liquid-liquid interface. Solid particles with suitable wettability to both the oil and water phases adsorb to the oil-water interface, stabilizing the emulsion.
The oil-in-water Pickering emulsion of the present invention can be applied to a hard surface and dried to form a coating with synovial properties. The mechanism by which this characteristic is exhibited is unclear, but it is presumed that the solid particles that make up the Pickering emulsion form a network structure as they dry, forming a coating that retains the oil.
By using a Pickering emulsion, a stable emulsion can be obtained without reducing the amount of surfactant or adding surfactant.

1. Hard Surface Treatment Agent The hard surface treatment agent of the present invention contains an oil-in-water Pickering emulsion.
An example of a Pickering emulsion is one containing solid particles and an organic compound that has a binding ability to the solid particles. From the viewpoint of imparting sufficient stability to the emulsion, it is preferable that the organic compound is bound to the solid particles.

<Solid particles>
The solid particles used in the Pickering emulsion may be inorganic or organic, but from the viewpoint of producing the Pickering emulsion, anionic solid particles are preferred. The anionic solid particles are more preferably inorganic particles or crystalline organic particles. More preferred solid particles are one or more selected from the group consisting of anion-modified cellulose fibers having a type I crystal structure, silica particles, and carbon-based compounds having anionic groups.

Inorganic materials include metal particles (metals such as gold, silver, copper, aluminum, silicon, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zinc, palladium, platinum, iridium, and rhodium, as well as their alloys), metal oxides (silica, alumina, titanium oxide, zinc oxide, iron oxide, etc.), natural minerals (mica, talc, kaolin, mica, bentonite, smectite, etc.), insoluble salts (metal carbonates, sulfates, phosphates, etc.), semiconductor particles (CdSe, ZnS, InP, CdS, PbS, etc.), and carbon-based materials (carbon black, graphene, graphene oxide, nanodiamonds, metal carbides, etc.).

Examples of organic substances include polysaccharides (cellulose nanofibers, cellulose particles, starch), oil and fat powders, metal soaps, organic pigments, and polymer powders (fluororesins, silicone resins, polystyrene, polyolefins, polyamides, polyesters, acrylic resins, and methacrylic resins). Of these, crystalline organic particles such as cellulose nanofibers, cellulose particles, and metal soaps are preferred from the standpoint of emulsion stability.

The inorganic solid particles and the organic solid particles may be modified with an anionic group such as a carboxy group, or a cationic group such as a hydroxyl group or an amino group.
The solid particles are preferably anionic solid particles, more preferably solid particles having a carboxy group.
Specific examples of compounds that can be used as solid particles having anionic groups include carbon black having anionic groups and polysaccharides having anionic groups. These compounds are commercially available and can be easily obtained.

The solid particles may have any shape, including spherical, amorphous, fibrous, and sheet-like shapes.
The maximum length of the solid particles is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less from the viewpoint of suppressing aggregation of emulsion particles, and is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more from the viewpoint of ensuring sufficient adsorptive power to the liquid-liquid interface. These maximum particle lengths refer to the number average values of the major axes (the length of a straight line connecting the furthest points on the surface of a particle) of 50 randomly sampled powder particles observed with an optical microscope or an electron microscope.

When the solid particles are fibrous, such as cellulose nanofibers, i.e., when the aspect ratio is 5 or greater, the average fiber diameter is preferably 1 nm or greater, more preferably 2 nm or greater, from the viewpoint of ensuring sufficient adsorption to the liquid-liquid interface; on the other hand, from the viewpoint of suppressing aggregation of emulsions, it is preferably 5 μm or less, more preferably 1 μm or less, and even more preferably 500 nm or less. Furthermore, when the solid particles are fibrous, such as cellulose nanofibers, the average fiber length is preferably 10 nm or greater, more preferably 50 nm or greater, and even more preferably 100 nm or greater, from the viewpoint of ensuring sufficient adsorption to the liquid-liquid interface; on the other hand, from the viewpoint of suppressing aggregation of emulsions, it is preferably 1 mm or less, more preferably 100 μm or less, and even more preferably 10 μm or less. The average fiber diameter and average fiber length can be determined by the methods described below.

Furthermore, when the solid particles are in the form of a sheet, their thickness is preferably 500 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less, in order to prevent the emulsions from agglomerating.

One example of a cellulose nanofiber is a polysaccharide having anionic groups. Examples of polysaccharides having anionic groups include cellulose fibers that have been anionically modified to include anionic groups within the cellulose fibers.

[Anion-modified cellulose fiber]
The anionically modified cellulose fibers used in the present invention are cellulose fibers that have been anionically modified so as to contain anionic groups.

Anion-modified cellulose fibers have a cellulose type I crystal structure. From the viewpoint of strength development during film formation, the crystallinity of the anion-modified cellulose fibers is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. From the viewpoint of raw material availability, the crystallinity is preferably 90% or less, more preferably 85% or less, even more preferably 80% or less, and even more preferably 75% or less. Note that, in this specification, the crystallinity of various cellulose fibers refers to the cellulose type I crystallinity calculated from the diffraction intensity value obtained by X-ray diffraction, and can be measured according to the method described in the Examples below. Note that cellulose type I refers to the crystalline form of native cellulose, and cellulose type I crystallinity refers to the proportion of crystalline regions in the entire cellulose fiber. The presence or absence of cellulose type I crystal structure can be determined by the presence of a peak at 2θ = 22.6° in X-ray diffraction measurement.

Examples of the anionic groups contained in anion-modified cellulose fibers include carboxy groups, sulfonic acid groups, and phosphate groups. From the viewpoint of the efficiency of introducing modifying groups into cellulose fibers, the anionic groups are preferably carboxy groups. Examples of counter ions to the anionic groups in anion-modified cellulose fibers include metal ions such as sodium ions, potassium ions, calcium ions, and aluminum ions that are generated in the presence of alkali during production, and protons that are generated by replacing these metal ions with acid.

Examples of methods for introducing carboxy groups into cellulose fibers include a method of converting hydroxy groups of cellulose into carboxy groups by oxidation, and a method of reacting the hydroxy groups of cellulose with at least one selected from the group consisting of compounds having carboxy groups, acid anhydrides of compounds having carboxy groups, and derivatives thereof.
The method for oxidizing the hydroxy groups of cellulose is not particularly limited, but for example, a method of oxidizing the cellulose by reacting an oxidizing agent such as sodium hypochlorite with a bromide such as sodium bromide using 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) as a catalyst can be applied. For more details, known methods, such as the method described in JP 2011-140632 A, can be referenced.

By subjecting cellulose fibers to an oxidation treatment using TEMPO as a catalyst, the hydroxymethyl group (—CH ₂ OH) at the C6 position of the cellulose structural unit is selectively converted to a carboxy group. This method is particularly advantageous in that it has excellent selectivity for the hydroxy group at the C6 position, which is the target of oxidation on the surface of the raw cellulose fiber, and the reaction conditions are mild. Therefore, a preferred embodiment of the anion-modified cellulose fiber in the present invention is a cellulose fiber in which the C6 position of the cellulose structural unit is a carboxy group. In this specification, such cellulose fibers may be referred to as "oxidized cellulose fibers." Oxidized cellulose fibers are preferred because they are easier to prepare than other anion-modified cellulose fibers.

From the viewpoint of introducing modifying groups, the anionic group content in anion-modified cellulose fibers is preferably 0.1 mmol/g or more, more preferably 0.4 mmol/g or more, even more preferably 0.6 mmol/g or more, and even more preferably 0.8 mmol/g or more. Furthermore, from the viewpoint of improving handleability, the anionic group content is preferably 3 mmol/g or less, more preferably 2 mmol/g or less, and even more preferably 1.8 mmol/g or less. The term "anionic group content" refers to the total amount of anionic groups in the cellulose that constitutes the cellulose fibers, and is specifically measured by the method described in the Examples below.

Carboxy group-containing cellulose fibers in which the anionic groups are carboxy groups are more preferred as anion-modified cellulose fibers, from the viewpoints of ease of preparation and mild reaction conditions.

<Organic compounds having bonding properties>
The organic compound having a binding property in the present invention is an organic compound having a binding property to solid particles, and when the solid particles are anionic solid particles, the organic compound is preferably an organic compound having a cationic functional group.

As an organic compound having a cationic functional group, an organic compound having an amino group is preferred. Examples of organic compounds having an amino group include polymeric compounds having an amino group and hydrocarbon compounds having an amino group.

(i) Amino group-containing polymer compounds The amino group-containing polymer compounds that can be preferably used in the present invention are commercially available or can be prepared according to known methods. Only one type of amino group-containing polymer compound may be used, or two or more types may be used.
Examples of the polymer compound having an amino group in the present invention include resins such as amino-modified silicone, polyoxyalkyleneamine, amino-modified poly(meth)acrylate polymer, amino-modified vinyl polymer, amino-modified polyester, amino-modified polycarbonate, polyallylamine, polyethyleneimine, etc.; chain aliphatic polyamine, cyclic aliphatic polyamine, alicyclic aromatic polyamine, etc., and the position of the reactive group may be any of the main chain, side chain, or terminal of the polymer compound. Among these, amino-modified silicone is preferred from the viewpoint of obtaining a film having synovial properties.

The amino-modified silicone is a silicone-based compound having an amino group. The amino-modified silicone preferably has a kinematic viscosity of 10 mm ² /s or more and 20,000 mm ² /s or less at 25° C. Furthermore, the amino-modified silicone preferably has an amino equivalent of 400 g/mol or more and 16,000 g/mol or less.

The kinematic viscosity at 25°C can be determined using an Ostwald viscometer, and from the viewpoint of obtaining a film with excellent release properties, it is more preferably 20 mm ² /s or more, even more preferably 50 mm ² /s or more, and from the viewpoint of handleability, it is more preferably 10,000 mm ² /s or less, even more preferably 5,000 mm ² /s or less.

The amino equivalent is preferably 400 g/mol or more, more preferably 600 g/mol or more, and even more preferably 800 g/mol or more, from the viewpoint of obtaining a film with excellent release properties. From the viewpoint of ease of bonding to anion-modified cellulose fibers, the amino equivalent is preferably 16,000 g/mol or less, more preferably 14,000 g/mol or less, and even more preferably 12,000 g/mol or less. The amino equivalent is the molecular weight per nitrogen atom and is calculated by the formula: amino equivalent (g/mol) = weight-average molecular weight/number of nitrogen atoms per molecule. Here, the weight-average molecular weight is a value determined by gel permeation chromatography using polystyrene as a standard substance, and the number of nitrogen atoms can be determined by elemental analysis.

Specific examples of amino-modified silicones include compounds represented by general formula (a1):

[In the formula, R ^1a represents a group selected from an alkyl group having 1 to 3 carbon atoms, a hydroxy group, an alkoxy group having 1 to 3 carbon atoms, or a hydrogen atom, and is preferably a methyl group or a hydroxy group from the viewpoint of obtaining a film with excellent mold releasability. R ^2a represents a group selected from an alkyl group having 1 to 3 carbon atoms, a hydroxy group, or a hydrogen atom, and is preferably a methyl group or a hydroxy group from the same viewpoint. B represents a side chain having at least one amino group, and R ^3a represents an alkyl group having 1 to 3 carbon atoms or a hydrogen atom. x and y each represent the average degree of polymerization, and are selected so that the kinematic viscosity at 25°C and amino equivalent of the compound fall within the above-mentioned ranges. R ^1a , R ^2a , and R ^3a may be the same or different, and multiple R ^2a may be the same or different.]

In the compound of general formula (a1), from the viewpoint of obtaining a film with excellent release properties, x is preferably a number of 10 or more and 10,000 or less, more preferably a number of 20 or more and 5,000 or less, and even more preferably a number of 30 or more and 3,000 or less. y is preferably a number of 1 or more and 1,000 or less, more preferably a number of 1 or more and 500 or less, and even more preferably a number of 1 or more and 200 or less. The weight-average molecular weight of the compound of general formula (a1) is preferably a number of 2,000 or more and 1,000,000 or less, more preferably a number of 5,000 or more and 100,000 or less, and even more preferably a number of 8,000 or more and 50,000 or less.

In the general formula (a1), examples of the side chain B having an amino group include the following.
-C ₃ H ₆ -NH ₂
-C ₃ H ₆ -NH-C ₂ H ₄ -NH ₂
-C ₃ H ₆ -NH- [C ₂ H ₄ -NH] _e -C ₂ H ₄ -NH ₂
-C ₃ H ₆ -NH(CH ₃ )
-C ₃ H ₆ -NH-C ₂ H ₄ -NH(CH ₃ )
-C ₃ H ₆ -NH-[C ₂ H ₄ -NH] _f -C ₂ H ₄ -NH(CH ₃ )
-C ₃ H ₆ -N(CH ₃ ) ₂
-C ₃ H ₆ -N(CH ₃ )-C ₂ H ₄ -N(CH ₃ ) ₂
-C ₃ H ₆ -N(CH ₃ )-[C ₂ H ₄ -N(CH ₃ )] _g -C ₂ H ₄ -N(CH ₃ ) ₂
-C ₃ H ₆ -NH-cyclo-C ₅ H ₁₁
(where e, f, and g are numbers from 1 to 30.)

The amino-modified silicone used in the present invention can be produced, for example, by hydrolyzing an organoalkoxysilane represented by general formula (a2) with an excess of water to obtain a hydrolyzate, and then heating the resulting hydrolyzate with dimethylcyclopolysiloxane in the presence of a basic catalyst such as sodium hydroxide to 80 to 110°C to cause an equilibrium reaction, and then neutralizing the basic catalyst with an acid when the reaction mixture reaches the desired viscosity (see JP 53-98499 A).
_H2N ( _CH2 ) _2NH ( _CH2 ) _3Si ( _CH3 )( _OCH3 ) ₂ (a2)

Furthermore, from the viewpoint of obtaining a film with excellent release properties, the amino-modified silicone is preferably at least one selected from the group consisting of monoamino-modified silicones having one amino group in each side chain B and diamino-modified silicones having two amino groups in each side chain B, and more preferably at least one selected from the group consisting of compounds in which the side chain B having an amino group is represented by -C ₃ H ₆ -NH ₂ [hereinafter referred to as component (a1-1)] and compounds in which the side chain B having an amino group is represented by -C ₃ H ₆ -NH-C ₂ H ₄ -NH ₂ [hereinafter referred to as component (a1-2)].

In terms of performance, the amino-modified silicones used in the present invention include TSF4703 (kinematic viscosity: 1000, amino equivalent: 1600) and TSF4708 (kinematic viscosity: 1000, amino equivalent: 2800) manufactured by Momentive Performance Materials, Inc., and SS-3551 (kinematic viscosity: 1000, amino equivalent: 1700), SF8457C (kinematic viscosity: 1200, amino equivalent: 1800), SF8417 (kinematic viscosity: 1200, amino equivalent: 1700), SF8452C (kinematic viscosity: 600, amino equivalent: 6400), BY16-209 (kinematic viscosity: 500, amino equivalent: 1800), and BY16-892 (kinematic viscosity: 1500, amino equivalent: 1800) manufactured by Dow-Toray. amino equivalent: 2000), BY16-898 (kinematic viscosity: 2000, amino equivalent: 2900), FZ-3760 (kinematic viscosity: 220, amino equivalent: 1600), BY16-213 (kinematic viscosity: 55, amino equivalent: 2700), Shin-Etsu Chemical Co., Ltd.'s KF-8002 (kinematic viscosity: 1100, amino equivalent: 1700), KF-8004 (kinematic viscosity: 800, amino equivalent: 1500), KF-8005 (kinematic viscosity: 1200, amino equivalent: 11000), KF-867 (kinematic viscosity: 1300, amino equivalent: 1700), KF-864 (kinematic viscosity: 1700, amino equivalent: 3800), KF-859 (kinematic viscosity: 60, amino equivalent: 6000), are preferred. In parentheses, the kinematic viscosity is the value measured at 25° C. (unit: mm ² /s), and the unit of amino equivalent is g/mol.

More preferred examples of component (a1-1) are BY16-213 (kinematic viscosity: 55, amino equivalent: 2700) and BY16-853U (kinematic viscosity: 14, amino equivalent: 450).

More preferred examples of component (a1-2) include SF8417 (kinematic viscosity: 1200, amino equivalent: 1700), BY16-209 (kinematic viscosity: 500, amino equivalent: 1800), FZ-3760 (kinematic viscosity: 220, amino equivalent: 1600), SF8452C (kinematic viscosity: 600, amino equivalent: 6400), KF-8002 (kinematic viscosity: 1100, amino equivalent: 1700), and SS-3551 (kinematic viscosity: 1000, amino equivalent: 1700).

The amino-modified silicone may have a substituent. Examples of the substituent include alkoxy groups having 1 to 6 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, and hexyloxy; methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, and sec-butoxycarbonyl; Examples of such groups include alkoxycarbonyl groups having 1 to 6 carbon atoms in the alkoxy group, such as a carboxyl group, tert-butoxycarbonyl group, pentyloxycarbonyl group, and isopentyloxycarbonyl group; halogen atoms such as a fluorine atom, chlorine atom, bromine atom, and iodine atom; acyl groups having 1 to 6 carbon atoms, such as an acetyl group and a propionyl group; aralkyl groups; aralkyloxy groups; alkylamino groups having 1 to 6 carbon atoms; and dialkylamino groups having an alkyl group with 1 to 6 carbon atoms.

(ii) Hydrocarbon Compound Having Amino Group The hydrocarbon compound having an amino group is a compound in which one or more hydrocarbon groups are bonded to one amino group. From the viewpoint of obtaining a film having excellent releasability, the total carbon number of the hydrocarbon compound having an amino group is preferably 16 or more, more preferably 18 or more, and from the viewpoint of handling, it is preferably 40 or less, more preferably 30 or less, and even more preferably 26 or less.

In a hydrocarbon compound having an amino group, when the amino group is a primary amine, secondary amine, tertiary amine, quaternary ammonium, phosphonium, or the like, the hydrocarbon group is directly bonded to a nitrogen atom or a phosphorus atom via a covalent bond.
The hydrocarbon compound having an amino group is more preferably one that does not contain an oxyalkylene group.

(hydrocarbon group)
Examples of the hydrocarbon group in the hydrocarbon compound include a chain saturated hydrocarbon group, a chain unsaturated hydrocarbon group, a cyclic saturated hydrocarbon group, and an aromatic hydrocarbon group. From the viewpoint of availability, the number of carbon atoms in the hydrocarbon group is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, even more preferably 12 or more, and even more preferably 16 or more, and from the same viewpoint, it is preferably 40 or less, more preferably 30 or less, and even more preferably 24 or less. Note that the number of carbon atoms in the hydrocarbon group means the number of carbon atoms in one hydrocarbon group, unless otherwise specified.

Specific examples of chain saturated hydrocarbon groups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, pentyl, tert-pentyl, isopentyl, hexyl, isohexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl, octadecyl, docosyl, and octacosanyl groups.

Specific examples of chain unsaturated hydrocarbon groups include ethenyl, propenyl, butenyl, isobutenyl, isoprenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, dodecenyl, tridecenyl, tetradecenyl, and octadecenyl groups.

Specific examples of cyclic saturated hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cyclododecyl, cyclotridecyl, cyclotetradecyl, and cyclooctadecyl groups.

The aromatic hydrocarbon group is, for example, selected from the group consisting of aryl groups and aralkyl groups. In the aryl group and aralkyl group, the aromatic ring itself may be substituted or unsubstituted.

Examples of aryl groups include phenyl groups, naphthyl groups, anthryl groups, phenanthryl groups, biphenyl groups, triphenyl groups, terphenyl groups, and groups in which these groups are substituted with the substituents described below.

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

The above hydrocarbon compounds may further have some hydrogen atoms substituted. Examples of the substituent include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, hydroxy groups, methoxy groups, ethoxy groups, carboxy groups, aldehyde groups, ketone groups, and thiol groups.

The above-mentioned hydrocarbon compound having an amino group is preferably a hydrocarbon compound having an amino group, such as a primary amine, secondary amine, tertiary amine, or quaternary ammonium (referred to herein as a "hydrocarbon amine"). Specific examples of such hydrocarbon amines include hexadecylamine, stearylamine, oleylamine, dioctylamine, didecylamine, didodecylamine, trihexylamine, trioctylamine, tetrabutylammonium salt, tetrahexylammonium salt, dimethyldioctylammonium salt, dimethyldidecylammonium salt, and trimethylhexadecylammonium salt.

[Hydrophobically modified cellulose fiber]
When the solid particles are anion-modified cellulose fibers having a type I crystal structure and the organic compound having binding properties is an amino-modified silicone or a hydrocarbon amine, the two are bonded together in the Pickering emulsion to form hydrophobically modified cellulose fibers. In the hydrophobically modified cellulose fibers, modifying groups derived from the amino-modified silicone or hydrocarbon amine are bonded to specific groups of the anion-modified cellulose fibers having a type I crystal structure. The bonding sites of the modifying groups are one or more groups selected from the group consisting of anionic groups and hydroxy groups.

When the bonding site is a hydroxy group of anion-modified cellulose fiber, the bonding type is a covalent bond, such as an ether bond, ester bond, or carbonate bond.

When the bonding site is an anionic group of anion-modified cellulose fibers, the bonding mode is an ionic bond or a covalent bond. When the bonding mode is an ionic bond, the modifying compound having a cationic group is bonded via electrostatic interaction. When the bonding mode is a covalent bond, the modifying compound is bonded via an ester bond, amide bond, etc. In particular, when the modifying compound is bonded to a carboxy group of carboxy-containing cellulose fibers, the modifying compound is bonded via an ester bond, amide bond, carbonate bond, urethane bond, etc.

For example, if the compound for introducing the modifying group (referred to herein as the "modifying compound") is an amino-modified silicone (referred to as "H ₂ N-[alkyl silicone skeleton]") and the anion-modified cellulose fiber is a carboxyl group-containing cellulose fiber (referred to as "[cellulose skeleton]-C ⁶ (═O)-OH"), and the bonding mode is an ionic bond, the hydrophobically modified cellulose fiber will have a structure such as "[cellulose skeleton]-C ⁶ (═O)-O-H ₃ N ⁺ -[alkyl silicone skeleton]", and the modifying group will be "-[alkyl silicone skeleton]". On the other hand, if the bonding mode is an amide bond, the hydrophobically modified cellulose fiber will have a structure such as "[cellulose skeleton]-C ⁶ (═O)-NH-[alkyl silicone skeleton]", and the modifying group will be "-[alkyl silicone skeleton]". Thus, the structure of the modifying group depends on the structure of the modifying compound used. Note that "C ⁶ " refers to the carbon atom at the 6th position of the cellulose structural unit.

One preferred embodiment of hydrophobically modified cellulose fibers formed by bonding amino-modified silicone to cellulose fibers has a structure represented by the following general formula (T-Ce):

(In the formula, X is ^one or more groups selected from the group consisting of —CH ₂ OH, —CH ₂ O—R ¹ , —C(═O)OH, —C(═O)O—R 1 , —C(═O)—O—H ₃ N ⁺ —R ¹ , and —C(═O)—NH—R ¹ ; R ¹ is a modifying group; each R is independently a hydrogen atom or a modifying group; R ¹ and R may be the same or different; and at least one of the multiple R ^1s and Rs is a modifying group; and m is an integer of 20 or more and 3,000 or less.)

The modifying group in the hydrophobically modified cellulose fibers obtained by bonding an amino-modified silicone to an anion-modified cellulose fiber having a type I crystal structure is a group derived from the amino-modified silicone, and the structure of the modifying group (i.e., ^R1 and R in the formula (T-Ce)) depends on the structure of the amino-modified silicone used. The bonding mode of the modifying group to the cellulose fiber is preferably a covalent bond or an ionic bond. From the viewpoint of ease of production, an ionic bond is preferred, and from the viewpoint of the stability of the film formed, a covalent bond is preferred.

<Water>
The hard surface treatment agent of the present invention contains water.
Water serves as a solvent in preparing the Pickering emulsion and as one of the components of the hard surface treatment agent of the present invention.

<Oil>
The hard surface treatment agent of the present invention contains an oil agent.
The oil agent is preferably an organic compound that is liquid at 25° C. and 1 atmosphere.
The solubility in water of an organic compound that is liquid at 25°C and 1 atmosphere is preferably 10 g or less, and more preferably 1 g or less, per 100 g of water at 25°C.
From the viewpoint of obtaining a film with improved synovial properties, the molecular weight of the oil is preferably 100,000 or less, more preferably 50,000 or less, and even more preferably 10,000 or less, and from the same viewpoint, it is preferably 100 or more, and more preferably 200 or more.

From the viewpoint of obtaining a film with improved synovial properties, examples of oil agents include one or more selected from the group consisting of alcohol, ester oil, hydrocarbon oil, silicone oil, ether oil, oils and fats, fluorine-based inert liquids, and fatty acids. One or more selected from the group consisting of ester oil, silicone oil, ether oil, oils and fats, and fluorine-based inert liquids are preferred. One or more selected from the group consisting of silicone oil, ester oil, and ether oil are more preferred, and silicone oil and/or ester oil are even more preferred.

Ester oils include monoester oils, diester oils, and triester oils. Specific examples include aliphatic or aromatic monocarboxylic or dicarboxylic acid esters having 2 to 18 carbon atoms, such as isopropyl myristate, octyldodecyl myristate, myristyl myristate, 2-hexyldecyl myristate, isopropyl palmitate, glyceryl tri-2-ethylhexanoate, and glyceryl triisostearate.

Examples of silicone oils include dimethylpolysiloxane, methylpolysiloxane, methylphenylpolysiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

Examples of fats and oils include vegetable oils such as soybean oil, palm oil, linseed oil, cottonseed oil, rapeseed oil, and castor oil, as well as animal oils.

From the viewpoint of producing a Pickering emulsion, the SP value of the oil compound is preferably 10 or less, more preferably 9.5 or less, even more preferably 9.0 or less, and even more preferably 8.5 or less; from the same viewpoint, it is preferably 6.0 or more, more preferably 6.5 or more.

The SP value in this specification refers to the solubility parameter (unit: (cal/ ^cm3 ) ^1/2 ) calculated by the Fedors method, and is described, for example, in references such as "SP Value Basics, Applications and Calculation Methods" (Johokkisha, 2005) and Polymer Handbook Third Edition (A Wiley-Interscience publication, 1989).

Examples of oils with an SP value of 10 or less that can be used in the present invention include oleic acid (SP value: 9.2), D-limonene (SP value: 9.4), PEG 400 (SP value: 9.4), dimethyl succinate (SP value: 9.9), neopentyl glycol dicaprate (SP value: 8.9), hexyl laurate (SP value: 8.6), isopropyl laurate (SP value: 8.5), isopropyl myristate (SP value: 8.5), isopropyl palmitate (SP value: 8.5), isopropyl oleate (SP value: 8.6), hexadecane (SP value: 8.0), olive oil (SP value: 9.3), jojoba oil (SP value: 8.6), squalane (SP value: 7.9), liquid paraffin (SP value: 7.9), fluorine Inert liquids (e.g., Fluorinert FC-40 (manufactured by 3M, SP value: 6.1), Fluorinert FC-43 (manufactured by 3M, SP value: 6.1), Fluorinert FC-72 (manufactured by 3M, SP value: 6.1), Fluorinert FC-770 (manufactured by 3M, SP value: 6.1)), silicone oils (e.g., KF96-1cs (manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7 .3), KF-96-10cs (Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96-50cs (Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96-100cs (Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96-1000cs (Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96H-10,000cs (Shin-Etsu Chemical Co., Ltd., SP value: 7.3), etc.

<Polyether-modified silicone compound>
The hard surface treatment agent of the present invention may further contain a polyether-modified silicone compound. By incorporating such a component into the hard surface treatment agent, a film with improved releasability can be obtained. An example of a polyether-modified silicone compound is a compound having a methylsilicone chain as the main chain and a polyoxyethylene group as the side chain, and specifically, a compound represented by the following general formula:

(In the formula, R ¹ is a methylene group, ethylene group, or trimethylene group, R ² is an alkyl group having 1 to 4 carbon atoms, m is an integer of 0 to 50, n is an integer of 1 to 10, p is an integer of 1 to 50, and q is an integer of 0 to 50. In the group represented by -R ¹ (C ₂ H ₄ O) _p (C ₃ H ₆ O) _q R ² , (C ₂ H ₄ O) _p and (C ₃ H ₆ O) _q may be random or block.)

From the viewpoint of obtaining a film with excellent release properties upon drying of the hard surface treatment agent, the HLB value of the polyether-modified silicone compound is preferably within a specific range; specifically, it is preferably 1 or greater, more preferably 5 or greater, and even more preferably 10 or greater, and is preferably 18 or less, more preferably 16 or less.

When two or more polyether-modified silicones with different HLB values are used, the weighted average HLB value of these silicones should fall within the above range. The HLB value is an index that represents the balance between hydrophilicity and lipophilicity, and in the present invention refers to the value calculated using the following Griffin equation:
HLB value = 20 x sum of molecular weights of hydrophilic groups / molecular weight

From the viewpoint of obtaining a film with excellent release properties by drying the hard surface treatment agent, the kinematic viscosity of the polyether-modified silicone compound at 25°C is preferably within a specific range, specifically, preferably 1 mm ² /s or more, more preferably 5 mm ² /s or more, and preferably 1000 mm ² /s or less, more preferably 500 mm ² /s or less, and even more preferably 200 mm ² /s or less.

Polyether-modified silicone compounds are commercially available, and examples of commercially available products include KF-615A, KF-640, KF-642, KF-643, KF-644, KF-351A, KF-354L, KF-355A, KF-6011, KF-6012, KF-6015, KF-6016, KF-6017, KF-6020, and KF-6043 manufactured by Shin-Etsu Chemical Co., Ltd. From the viewpoint of obtaining a film with excellent release properties upon drying of the hard surface treatment agent, KF-640, KF-642, KF-643, KF-351A, KF-354L, and KF-355A are preferred. Commercially available products with structures that do not conform to the above general formula (e.g., KF-6028 and KF-6038 manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as polyether-modified silicone compounds.

<Volatile organic compounds>
The hard surface treatment agent of the present invention may further contain an organic compound other than those corresponding to the oil agent, which is volatile at 25°C and 1 atmosphere (such organic compound is referred to as a "volatile organic compound" in this specification). By incorporating such a component into the Pickering emulsion or the hard surface treatment agent, it is possible to more easily form a film on the substrate, which is preferable. In this specification, an organic compound that is volatile at 25°C and 1 atmosphere means an organic compound whose vapor pressure under such conditions is 10 Pa or more.

Such components include, for example, N-methylpyrrolidone, 2-propanol, 1-propanol, ethanol, methanol, t-butanol, 1-butanol, 2-butanol, toluene, xylene, methyl ethyl ketone, acetone, ethyl acetate, dimethylformamide, methyl isobutyl ketone, acetonitrile, dimethyl sulfoxide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, hexane, cyclohexane, cyclohexanone, 1,4-dioxane, chloroform, dichloromethane, diethyl ether, and mixtures thereof.

<High molecular compound>
The hard surface treatment agent of the present invention may further contain a polymer compound other than the above-mentioned polymer compound having an amino group, for example, one or more selected from the group consisting of the following polymer compound (X) and polymer compound (Y). By incorporating such a component into the emulsion composition, the durability of the film can be improved, which is preferable.
Polymer compound (X): Methacrylic or acrylic polymer having an ester group or an amide group in the side chain Polymer compound (Y): Polymer compound having an ester group, an amide group, a urethane group, an ether group, or a carbonate group in the main chain

The weight average molecular weight of the polymer compound (X) is preferably 1,000 or more from the viewpoint of improving the durability of the film, and from the same viewpoint, is preferably 500,000 or less.
Examples of the polymer compound (X) include polyalkyl(meth)acrylates such as polymethyl(meth)acrylate, polyethyl(meth)acrylate, and polybutyl(meth)acrylate; copolymers with acrylic such as styrene-acrylic and urethane-acrylic; and poly(meth)acrylamides such as poly(meth)acrylamide, poly-N-methyl(meth)acrylamide, poly-N,N-dimethyl(meth)acrylamide, and poly-N-phenyl(meth)acrylamide.

2. Method for Producing the Hard Surface Treatment Agent The hard surface treatment agent of the present invention can be produced, for example, by mixing the above-mentioned components (A), (B), (C), and the like.

Mixing the components causes emulsification, resulting in a Pickering emulsion. For this mixing process, a magnetic stirrer, mechanical stirrer, homomixer, vacuum emulsifier, low-pressure homogenizer, high-pressure homogenizer, grinder, cutter mill, ball mill, jet mill, single-screw extruder, twin-screw extruder, ultrasonic agitator, household juicer mixer, etc. can be used. The mixing process may also be performed by combining two or more operations.

The temperature and time for mixing the components are not particularly limited, but are preferably in the range of 5 to 50°C and 1 minute to 3 hours, for example.

The preferred range of content of each component when mixed is the same as the preferred range of content of each component in the Pickering emulsion of the present invention described above.

The blending ratio of the anionic solid particles to the organic compound having a cationic functional group is preferably 0.1 equivalents or more, more preferably 0.3 equivalents or more, and even more preferably 0.5 equivalents or more, of the organic compound having a cationic functional group relative to the anionic groups of the anionic solid particles, from the viewpoints of synovial properties and durability. On the other hand, from the viewpoint of the stability of the Pickering emulsion, the blending ratio is preferably 3 equivalents or less, more preferably 2 equivalents or less, and even more preferably 1.5 equivalents or less.

Alternatively, the ratio of the total number of moles of the amino groups of the amino-modified silicone and the amino groups of the hydrocarbon amine to the number of moles of anionic groups of the anionic solid particles is preferably 0.1 or more, more preferably 0.3 or more, and even more preferably 0.5 or more, from the viewpoint of obtaining a film with improved synovial properties and durability, and is preferably 3 or less, more preferably 2 or less, and even more preferably 1.5 or less, from the viewpoint of film-formability. The number of moles of anionic groups in the anion-modified cellulose fiber can be obtained by multiplying the amount (g) of anion-modified cellulose fiber used by the anionic group content (mmol/g), and the number of moles of amino groups in the amino-modified silicone can be obtained by dividing the amount (g) of amino-modified silicone used by the amino equivalent (g/mol).

Furthermore, from the viewpoint of obtaining a film with improved synovial properties and durability, the mass ratio of the organic compound having a cationic functional group to the oil ([organic compound having a cationic functional group]/[oil]) is preferably 0.0001 or more, more preferably 0.001 or more, even more preferably 0.004 or more, even more preferably 0.01 or more, and even more preferably 0.04 or more; from the viewpoint of film-forming properties, it is preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, even more preferably 3 or less, and even more preferably 2 or less. From these viewpoints, it is preferably 0.0001 or more and 20 or less, more preferably 0.001 or more and 10 or less, even more preferably 0.004 or more and 5 or less, even more preferably 0.01 or more and 3 or less, and even more preferably 0.04 or more and 2 or less.

3. Properties of the Hard Surface Treatment Agent The hard surface treatment agent of the present invention is an emulsified composition containing the above-mentioned components as essential components. The emulsification in the present invention is achieved by mixing water and an organic compound that is liquid at 25°C and 1 atmosphere, and then applying mechanical force to the mixture to create a state in which droplets of one liquid are finely dispersed in the other liquid. The emulsion type is an oil-in-water emulsion.

The content of [the total of solid particles and organic compounds capable of binding thereto] in the Pickering emulsion or during mixing is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of emulsifying power; on the other hand, from the viewpoint of handleability, it is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

The water content in the Pickering emulsion or during mixing is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of maintaining the emulsified state, and is preferably 98% by mass or less, from the viewpoint of the effective amount.

The content of oil in the Pickering emulsion or during mixing is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, from the viewpoint of maintaining the emulsified state. On the other hand, from the viewpoint of solution viscosity and handleability, it is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

The mass ratio of the components [total of solid particles and organic compounds capable of binding thereto] to the oil in the Pickering emulsion or when mixed ([total of solid particles and organic compounds capable of binding thereto]/[oil]) is preferably 0.0001 or more, more preferably 0.001 or more, even more preferably 0.004 or more, even more preferably 0.01 or more, and even more preferably 0.04 or more, from the viewpoint of obtaining a film with improved synovial properties; and is preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, even more preferably 3 or less, and even more preferably 2 or less, from the viewpoint of film-forming properties. From these viewpoints, it is preferably 0.0001 or more and 20 or less, more preferably 0.001 or more and 10 or less, even more preferably 0.004 or more and 5 or less, even more preferably 0.01 or more and 3 or less, and even more preferably 0.04 or more and 2 or less.

When the hard surface treatment agent of the present invention contains a polyether-modified silicone compound, the content of the polyether-modified silicone compound is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and is preferably 2% by mass or less, more preferably 1% by mass or less.

When the hard surface treatment agent of the present invention contains the volatile organic compound, the content of such organic compound is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 5% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

When the hard surface treatment agent of the present invention contains one or more compounds selected from the group consisting of polymer compounds (X) and (Y), the content of the one or more compounds selected from the group consisting of polymer compounds (X) and (Y) is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less.

The viscosity of the Pickering emulsion is not particularly limited, but from the perspective of ease of handling, the viscosity at 25°C is preferably 0.5 mPa·s or more, more preferably 0.8 mPa·s or more, and even more preferably 1 mPa·s or more. From the same perspective, the viscosity is preferably 30 Pa·s or less, more preferably 20 Pa·s or less, and even more preferably 10 Pa·s or less. Here, the viscosity is measured using a Brookfield viscometer with an appropriate rotor tailored to the viscosity range of each sample at 25°C and 60 rpm after stirring for 1 minute.

The average particle size of the emulsified droplets in the Pickering emulsion, as measured by SEM observation as described below, is preferably 10 nm or more, more preferably 50 nm or more, and even more preferably 100 nm or more, from the viewpoint of improving synovial properties and durability; from the same viewpoint, it is preferably 2000 nm or less, more preferably 1000 nm or less, even more preferably 700 nm or less, and even more preferably 500 nm or less, preferably 10 nm or more and 2000 nm or less, more preferably 50 nm or more and 1000 nm or less, and even more preferably 100 nm or more and 500 nm or less.

4. Application of the hard surface treatment agent to a hard surface The hard surface treatment agent of the present invention is applied to a hard surface and dried to form a film on the hard surface.

Specifically, the treatment agent is applied to a hard surface, such as a solid surface made of glass, resin, metal, ceramics, concrete, wood, stone, paper, etc. Application methods include, but are not limited to, methods using an applicator, bar coder, spin coater, roller, etc., brush coating, hand coating, air spray, airless spray, trigger spray, spray from an aerosol can, dip coating, etc.

The thickness of the Pickering emulsion coating on a hard surface is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more, from the viewpoint of film durability, and is preferably 2000 μm or less, more preferably 1500 μm or less, from the viewpoint of coatability.

Then, the coating of Pickering emulsion can be dried to obtain a film. Drying conditions can be either under reduced pressure or normal pressure, and the temperature range is preferably 15°C or higher and 75°C or lower. Furthermore, the drying time is preferably 1 hour or higher and 24 hours or lower.

The dried film formed by the above method preferably exhibits the synovial surface properties shown in the literature (Technology for Super Water-Repellent, Super Oil-Repellent, and Synovial Surfaces / Publisher: Hiroshi Motoki / Publisher: Science & Technology Co., Ltd. / Published January 28, 2016).

Synovial surface properties can be measured, for example, by the method described in the "Sliding Angle Measurement Test" in the Examples below. The smaller the sliding angle value, the higher the synovial properties of the membrane.

The durability of the membrane is further improved by including the aforementioned polyether-modified silicone compound.

There are no particular restrictions on the thickness of the film, but from the viewpoint of film durability, it is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. From the viewpoint of economy, it is preferably 2000 μm or less, more preferably 1200 μm or less, even more preferably 500 μm or less, and even more preferably 200 μm or less. The desired film thickness can be achieved by setting the coating thickness using an application tool such as an applicator, or by adjusting the proportion of the medium. The film thickness can be measured according to the method described in the Examples below.

The smoother the membrane, the better its synovial properties, which is why it is preferable. Specifically, from the perspective of cost-effectiveness, the arithmetic mean roughness of the membrane surface immediately after production is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 0.8 μm or more. On the other hand, from the perspective of adhesion prevention, it is preferably 40 μm or less, more preferably 35 μm or less, and even more preferably 30 μm or less. The surface roughness of the membrane can be measured as the arithmetic mean roughness according to the method described in the Examples below.

High durability is preferred for films. Film durability can be evaluated, for example, by the degree of increase in the arithmetic mean roughness of the film after contact with water for a certain period of time, or by the presence or absence of synovial properties. Specifically, if a substrate on which such a film has been formed is held horizontally and water is continuously dripped onto the substrate from a height of 40 cm at a flow rate of 50 mL/sec for five minutes, and the arithmetic mean roughness of the film is no more than twice the roughness before dripping, and the film retains synovial properties after five minutes of dripping, then the film can be evaluated as having high durability.

From the viewpoint of film durability, the amount of solid particles in the film is preferably 1% by mass or more, more preferably 10% by mass or more, and from the viewpoint of film synovial properties, it is preferably 65% by mass or less, more preferably 36% by mass or less, and even more preferably 16% by mass or less. The amount of hydrophobically modified cellulose fiber in the film is calculated taking into account the amount of volatile components in the Pickering emulsion.

The film may contain optional components that do not impair the effects of the present invention. The content of these optional components in the film is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less.

By applying the hard surface treatment agent of the present invention to a hard surface, the hard surface can be modified into a synovial surface. The film formed not only has excellent synovial properties, but also has excellent durability, allowing its effectiveness to be maintained for a long period of time. Therefore, it is useful for a variety of applications, such as snow-proof paints, antifouling paints, antibacterial paints, flow resistance reducing agents, and mold release agents. Examples of applications include ships (ship bottoms, propellers, etc.), houses (e.g., roofs, walls, residential equipment, etc.), vehicles, building materials, piping, equipment, tools, panels, and containers. By applying the Pickering emulsion of the present invention to the above-mentioned hard surfaces, it can be used as a snow-proofing method, antifouling method, antibacterial method, flow resistance reducing method, and mold release method.

The present invention will be specifically explained below using examples. Please note that the following examples are merely illustrative of the present invention and are not intended to be limiting in any way.

[Average fiber diameter, average fiber length, and average aspect ratio of anionically modified cellulose fibers and hydrophobically modified cellulose fibers]
Water is added to the cellulose fibers to be measured to prepare a dispersion with a content of 0.0001% by mass. The dispersion is dropped onto mica and dried to serve as an observation sample. An atomic force microscope (AFM) (Digital Instruments, Nanoscope II Tapping mode AFM; Nanosensors, Point Probe (NCH) probe) is used to measure the fiber height (height difference between fiber-containing and fiber-free areas) of the cellulose fibers in the observation sample. At this time, 100 or more cellulose fibers are extracted from a microscopic image in which the cellulose fibers can be seen, and the average fiber diameter is calculated from their fiber height. The average fiber length is calculated from the distance in the fiber direction. The average aspect ratio is calculated by dividing the average fiber length by the average fiber diameter. The height analyzed in the AFM image can be considered the fiber diameter.

[Average fiber diameter and average fiber length of raw cellulose fibers]
Deionized water is added to the cellulose fibers to be measured to prepare a dispersion containing 0.01% by mass of cellulose. The dispersion is measured using a wet dispersion type image analysis particle size distribution analyzer (IF-3200, manufactured by Jusco International Co., Ltd.) under the following conditions: front lens: 2x, telecentric zoom lens: 1x, image resolution: 0.835 μm/pixel, syringe inner diameter: 6515 μm, spacer thickness: 500 μm, image recognition mode: ghost, threshold: 8, analysis sample volume: 1 mL, and sampling: 15%. At least 100 cellulose fibers are measured, and the average ISO fiber diameter and average ISO fiber length are calculated as the average fiber diameter and average fiber length, respectively.

[Anionic Group Content of Anionically Modified Cellulose Fibers and Hydrophobically Modified Cellulose Fibers]
A dry mass of 0.5 g of the cellulose fiber to be measured is placed in a 100 mL beaker, and deionized water or a 2:1 methanol/water mixed solvent is added to make a total volume of 55 mL. 5 mL of 0.01 M aqueous sodium chloride solution is then added to prepare a dispersion. The dispersion is stirred until the cellulose fiber to be measured is sufficiently dispersed. 0.1 M hydrochloric acid is added to the dispersion to adjust the pH to 2.5-3. Using an automatic titrator (DKK-TOA Corporation, AUT-701), 0.05 M aqueous sodium hydroxide solution is added dropwise to the dispersion with a waiting time of 60 seconds, and the conductivity and pH values are measured every minute. Measurements are continued until the pH reaches approximately 11, and a conductivity curve is obtained. The sodium hydroxide titration amount is determined from this conductivity curve, and the anionic group content of the cellulose fiber to be measured is calculated using the following formula:
Anionic group content (mmol/g) = [sodium hydroxide titration amount × sodium hydroxide aqueous solution concentration (0.05 M)] / [mass of cellulose fiber to be measured (0.5 g)]

[Aldehyde group content of oxidized cellulose fiber]
The carboxy group content of the oxidized cellulose fiber to be measured is measured by the above-mentioned method for measuring the anionic group content.
Separately, 100 g of the aqueous dispersion of oxidized cellulose fiber to be measured (solids content: 1.0% by mass), 100 g of acetate buffer (pH 4.8), 0.33 g of 2-methyl-2-butene, and 0.45 g of sodium chlorite were added to a beaker and stirred at 25°C for 16 hours to oxidize any remaining aldehyde groups in the oxidized cellulose fiber. After completion of the reaction, the fiber was washed with deionized water to obtain cellulose fiber with the aldehyde groups oxidized. The reaction solution was freeze-dried, and the carboxy group content of the resulting dried product was measured using the above-mentioned method for measuring anionic group content, and the "carboxy group content of the oxidized oxidized cellulose fiber" was calculated. Next, the aldehyde group content of the oxidized cellulose fiber to be measured was calculated using Equation 1.

Aldehyde group content (mmol/g) = (carboxyl group content of oxidized cellulose fiber after oxidation treatment) - (carboxyl group content of oxidized cellulose fiber to be measured) ... Equation 1

[Solid content in dispersion]
The measurement is carried out using a halogen moisture meter (MOC-120H, manufactured by Shimadzu Corporation). Measurements are carried out every 30 seconds for 1 g of sample at a constant temperature of 150°C, and the value when the mass loss is 0.1% or less of the initial amount of the sample is taken as the solid content.

[Confirmation of crystalline structure in hydrophobically modified cellulose fibers]
The crystalline structure of the hydrophobically modified cellulose fiber is confirmed by measurement under the following conditions using an X-ray diffractometer (MiniFlex II, manufactured by Rigaku Corporation).
The measurement conditions are as follows: X-ray source: Cu/Kα-radiation, tube voltage: 30 kV, tube current: 15 mA, measurement range: diffraction angle 2θ = 5 to 45°, X-ray scan speed: 10°/min. The measurement sample is compressed into a pellet with an area of 320 mm ² and a thickness of 1 mm. The crystallinity of the cellulose type I crystal structure is calculated from the obtained X-ray diffraction intensity according to the following formula A.

<Formula A>
Cellulose I-type crystallinity (%) = [(I _22.6 - I _18.5 )/I _22.6 ] × 100
(wherein I _22.6 represents the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ=22.6°) in X-ray diffraction, and I _18.5 represents the diffraction intensity of the amorphous portion (diffraction angle 2θ=18.5°).)

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

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

[Cellulose fiber (equivalent amount) in hydrophobically modified cellulose fiber]
The cellulose fiber (equivalent amount) in the hydrophobically modified cellulose fiber is measured by the following method.
(1) When one type of "modifying compound" is added, the amount of cellulose fiber (equivalent amount) is calculated by the following formula C.
<Formula C>
Amount of cellulose fiber (equivalent amount) (g) = Mass of hydrophobically modified cellulose fiber (g) / [1 + Molecular weight of modifying compound (g/mol) × Bond amount of modifying group (mmol/g) × 0.001]
(2) When two or more types of “modifying compounds” are added, the amount of cellulose fiber (equivalent amount) is calculated taking into account the molar ratio of each compound (i.e., the molar ratio when the total molar amount of the added compounds is 1).

[Measurement of viscosity of Pickering emulsion]
Using a Brookfield viscometer (Toki Sangyo TVB-10) with a No. 1 rotor, the viscosity is measured at 25°C, a rotation speed of 60 RPM, and after 1 minute.

[Observation of Pickering emulsions using a Cryo-SEM]
Observation of Pickering emulsions using a cryo-SEM is performed using a field emission scanning electron microscope, Scios DualBeam, manufactured by FEI. Observation is performed while gradually sublimating water from the frozen Pickering emulsion. Observation is performed at an accelerating voltage of 2 kV and a magnification of 25,000x.

[Measurement of emulsion droplet size by laser diffraction method]
The particle size of the emulsified droplets is measured by laser diffraction using an LA-960 manufactured by Horiba Ltd.
Measurement conditions: Water is added to a measurement cell, and the volume particle size distribution and volume median particle size (D ₅₀ ) are measured at a concentration that brings the absorbance into an appropriate range. The relative refractive index is 1.20, the temperature is 25°C, the circulation pump is ON, the circulation speed is 5, and the stirring speed is 5.

[Preparation of Anion-Modified Cellulose Fibers]
Preparation Example 1
Bleached coniferous kraft pulp (West Fraser, Hinton) was used as the raw material natural cellulose fiber. Commercially available TEMPO (Aldrich, Free Radical, 98% by mass) was used. Commercially available sodium hypochlorite, sodium bromide, and sodium hydroxide were used.

First, 10 g of the bleached kraft pulp fiber and 990 g of deionized water were weighed into a 2 L PP beaker equipped with a mechanical stirrer and impeller, and the mixture was stirred at 25°C and 100 rpm for 30 minutes. Then, 0.13 g of TEMPO, 1.3 g of sodium bromide, and 35.5 g of a 10.5% by mass aqueous solution of sodium hypochlorite were added to the 10 g of pulp fiber, in that order. Using a pH-stat titration system on an automatic titrator (DKK-TOA Corporation, AUT-701), 0.5 M aqueous sodium hydroxide was added dropwise to maintain the pH at 10.5. The reaction was continued for 120 minutes at 25°C with a stirring speed of 100 rpm, after which the addition of the aqueous sodium hydroxide solution was stopped, yielding a suspension of anion-modified cellulose fiber.

The resulting suspension of anion-modified cellulose fibers was adjusted to a pH of 2 by adding 0.01 M hydrochloric acid. The filtrate was then thoroughly washed with deionized water until the conductivity measured using a compact electrical conductivity meter (HORIBA, Ltd., LAQUAtwin EC-33B) was 200 μs/cm or less. The resulting filtrate was then dehydrated to yield anion-modified cellulose fibers. The carboxyl group content of the anion-modified cellulose fibers was 1.50 mmol/g, and the aldehyde group content was 0.23 mmol/g.

Preparation Example 2 (Production of finely divided anion-modified cellulose fibers)
Deionized water was added to the anion-modified cellulose fibers finally obtained in Preparation Example 1 to prepare 100 g of a suspension (solid content 2.0% by mass). A 0.5 M aqueous sodium hydroxide solution was added to the suspension to adjust the pH to 8, and deionized water was added to make a total of 200 g. This suspension was subjected to a micronization treatment three times at 150 MPa using a high-pressure homogenizer (NanoVita L-ES, manufactured by Yoshida Kikai Co., Ltd.) to obtain a micronized anion-modified cellulose fiber dispersion (solid content 1.0% by mass). The counter ions of the carboxy groups in this micronized anion-modified cellulose fiber were sodium ions. This micronized anion-modified cellulose fiber is abbreviated as "TCNF (Na type)."

Preparation Example 3 (Production of finely divided anion-modified cellulose fibers subjected to reduction treatment of aldehyde groups)
182 g of the finely divided anion-modified cellulose fiber dispersion (solid content 1.0% by mass) obtained in Preparation Example 2 was weighed out and deionized water was added to make a total of 400 g. 1.2 mL of 0.1 M aqueous sodium hydroxide and 120 mg of sodium borohydride were added and stirred at 25°C for 4 hours. Next, 9 mL of 1 M hydrochloric acid was added to carry out protonation. After the reaction was completed, the mixture was filtered, and the resulting cake was washed six times with deionized water to remove salts and hydrochloric acid, yielding a finely divided anion-modified cellulose fiber dispersion (solid content 0.9% by mass) in which the aldehyde groups had been reduced. The resulting cellulose fiber had a carboxyl group content of 1.50 mmol/g and an aldehyde group content of 0.02 mmol/g. The carboxyl groups in this finely divided anion-modified cellulose fiber were in the free acid form (COOH), and are abbreviated as "TCNF (H type)." The degree of crystallinity of the fine anion-modified cellulose fibers was 30%, the average fiber diameter was 3.3 nm, and the average fiber length was 600 nm.

Preparation Example 4 (Synthesis of silica fine particles with an average particle size of 400 nm)
500 g of ethanol, 45 g of ion-exchanged water, 20 g of ammonia water, and 30 g of tetraethoxysilane were mixed in a flask and stirred at room temperature for 12 hours. After that, the silica particles were separated from the solution by centrifugation (10,000 g, 10 minutes). The separated particles were then resuspended in water and freeze-dried to obtain a powder.
Five grams of this powder was suspended in ion-exchanged water to a concentration of 10% by mass, and dispersed for 5 minutes using an ultrasonic homogenizer (Nippon Seiki Seisakusho, US-300E, probe diameter 12 mm) to obtain silica microparticles dispersed in water. The number-average particle size measured by observation with a scanning electron microscope (JEOL Ltd., JSM-IT500HR, accelerating voltage 10 kV, magnification 50,000 times) was 400 nm.

[Preparation of Pickering emulsion]
Example 1
20 g of the micronized anion-modified cellulose fiber dispersion (solid content 0.9% by mass) obtained in Preparation Example 3, 1.8 g of 10cs silicone oil, and 0.6 g of amino-modified silicone were weighed into a beaker, and ion-exchanged water was added to make a total of 30 g. This solution was dispersed using an ultrasonic homogenizer (Nippon Seiki Seisakusho, US-300E, probe diameter 12 mm) for 5 minutes to obtain a Pickering emulsion stabilized by the micronized anion-modified cellulose fiber. This Pickering emulsion was used as a hard surface treatment agent.

Examples 2 to 6
A Pickering emulsion stabilized by fine particles was obtained in the same manner as in Example 1, except that the components were used in the proportions shown in Table 1. This Pickering emulsion was used as a hard surface treatment agent.

Comparative Example 1
1.8 g of 10cs silicone oil and 0.6 g of amino-modified silicone were weighed into a beaker, and ion-exchanged water was added to make a total of 30 g. This solution was dispersed for 5 minutes using an ultrasonic homogenizer (Nippon Seiki Seisakusho, US-300E, probe diameter 12 mm), but it immediately separated into two layers, and no emulsion was obtained.

Comparative Example 2
1.8 g of silicone oil 10cs, 0.6 g of amino-modified silicone, and 60 mg of Emulgen 109P were weighed into a beaker, and ion-exchanged water was added to make a total of 30 g. This solution was dispersed for 5 minutes using an ultrasonic homogenizer (Nippon Seiki Seisakusho, US-300E, probe diameter 12 mm) to obtain an emulsion stabilized by the surfactant.

[Emulsion Stability]
5 mL of each of the Pickering emulsions prepared in Examples 1 to 6 and the emulsion prepared in Comparative Example 2 was measured and placed in a vial and allowed to stand at room temperature. No separation was observed for more than one week, and the emulsion maintained a stable state.

[Creation of dry film]
400 μL of each of the Pickering emulsions prepared in Examples 1 to 6 and the emulsion prepared in Comparative Example 2 was applied to separate glass substrates (Micro Slide Glass S2112, manufactured by MATSUNAMI Co., Ltd.) and spread over the entire surface of the glass slide. The emulsions were then dried at 1 atmosphere, 25°C, and approximately 40% RH for 24 hours to prepare films. The thickness of the film of Example 1 was measured using the following measurement method and found to be 20 μm.

[Measurement of film thickness]
The thickness of the dried film was measured using a laser microscope (Keyence Corporation, VK-9710) under the following measurement conditions. The measurement conditions were: objective lens: 10x, light intensity: 3%, brightness: 1548, Z pitch: 0.5 μm. A part of the film was scraped off with a metal spatula, and the sample with the exposed glass substrate was measured. The height of the glass substrate and the height of the film were measured using the built-in image processing software, and the thickness of the film was calculated by taking the difference between them.

[Slide angle measurement test]
The dried films of Examples 1 to 6 and Comparative Example 2 prepared as described above were placed horizontally, and an 8 μL water droplet (23°C) was dropped onto each film at 23°C using a fully automatic contact angle meter (FAMAS, manufactured by Kyowa Interface Science Co., Ltd.) and allowed to stand for 1 second. The film surface was then tilted to 85° at a rate of 1°/s, and the angle at which the droplet began to slide was measured. The measurement results are shown in the table below. However, if the droplet did not slide even when tilted to 85°, the water droplet sliding angle was recorded as "85 or more." The smaller the water droplet sliding angle, the higher the synovial properties of the film.

Table 1 below summarizes the composition (mass%) and evaluation results for each composition.

The above experiments revealed the following:
It was found that a coating formed by applying a Pickering emulsion within the scope of the present invention to a substrate and drying it was able to slide off even minute water droplets at a slight incline, and had excellent lubrication properties.
In contrast, when no surfactant or solid particles were added (Comparative Example 1), a stable Pickering emulsion could not be prepared. Furthermore, the coating formed by applying an emulsion prepared using a surfactant (Comparative Example 2) to a substrate did not exhibit synovial properties.

Preparation Example 5
In a beaker, 66.7 g of the micronized anion-modified cellulose fiber dispersion obtained in Preparation Example 3 (solid content 0.9% by mass), 12 g of silicone oil 100cs, and 1.91 g of amino-modified silicone were weighed, and deionized water was added to make a total of 100 g. This solution was stirred with a mechanical stirrer for 5 minutes, and then processed 10 times at 150 MPa with a high-pressure homogenizer (Yoshida Kikai Co., Ltd., Nanovaita L-ES) to obtain a Pickering emulsion stabilized by the micronized anion-modified cellulose fiber. 0.2 g of polyether-modified silicone 1 was added thereto, and the mixture was stirred at 25 ° C. for 30 minutes to obtain a Pickering emulsion. The average emulsion particle size measured by laser diffraction was 300 nm, and the viscosity was 10 mPa s. The finally obtained Pickering emulsion was used as a hard surface treatment agent.

Preparation Example 6
In a beaker, 66.7 g of the micronized anion-modified cellulose fiber dispersion obtained in Preparation Example 3 (solid content 0.9% by mass), 6 g of silicone oil 10cs, and 1.91 g of amino-modified silicone were mixed, and deionized water was added to make a total of 100 g. This solution was stirred with a mechanical stirrer for 5 minutes, and then processed 10 times at 150 MPa with a high-pressure homogenizer (Yoshida Kikai Co., Ltd., Nanovaita L-ES) to obtain a Pickering emulsion stabilized by the micronized anion-modified cellulose fiber. 0.2 g of polyether-modified silicone 1 was added thereto, and the mixture was stirred at 25 ° C. for 30 minutes to obtain a Pickering emulsion. The finally obtained Pickering emulsion was used as a hard surface treatment agent.

Preparation Example 7
In a beaker, 66.7 g of the micronized anion-modified cellulose fiber dispersion obtained in Preparation Example 3 (solid content 0.9% by mass), 6 g of 100cs silicone oil, and 2.68 g of amino-modified silicone were mixed, and deionized water was added to make a total of 100 g. This solution was stirred with a mechanical stirrer for 5 minutes and then subjected to 10 passes at 150 MPa in a high-pressure homogenizer (NanoVita L-ES, manufactured by Yoshida Kikai Co., Ltd.) to obtain a Pickering emulsion stabilized by the micronized anion-modified cellulose fiber. The final Pickering emulsion obtained was used as a hard surface treatment agent.

Preparation Example 8
In a beaker, 66.7 g of the micronized anion-modified cellulose fiber dispersion obtained in Preparation Example 3 (solid content 0.9% by mass), 12 g of silicone oil 10cs, and 1.91 g of amino-modified silicone were mixed, and deionized water was added to make a total of 100 g. This solution was stirred with a mechanical stirrer for 5 minutes, and then processed 10 times at 150 MPa with a high-pressure homogenizer (Yoshida Kikai Co., Ltd., Nanovaita L-ES) to obtain a Pickering emulsion stabilized by the micronized anion-modified cellulose fiber. 0.2 g of polyether-modified silicone 1 was added thereto, and the mixture was stirred at 25 ° C. for 30 minutes to obtain a Pickering emulsion. The finally obtained Pickering emulsion was used as a hard surface treatment agent.

Preparation Example 9
In a beaker, 66.7 g of the finely divided anion-modified cellulose fiber dispersion obtained in Preparation Example 3 (solid content 0.9% by mass), 6 g of 100cs silicone oil, and 2.68 g of amino-modified silicone were mixed, and deionized water was added to make a total of 100 g. This solution was stirred with a mechanical stirrer for 5 minutes and then processed 10 times at 150 MPa with a high-pressure homogenizer (Yoshida Kikai Co., Ltd., Nanovaita L-ES) to obtain a Pickering emulsion stabilized by the finely divided anion-modified cellulose fiber. 0.2 g of polyether-modified silicone 2, 13.5 g of styrene acrylic (solid content 44.5% by mass), and 10 g of N-methylpyrrolidone were added, and the mixture was stirred at 25 ° C. for 30 minutes to obtain a Pickering emulsion. The finally obtained Pickering emulsion was used as a hard surface treatment agent.

The composition (mass%) of each emulsion is summarized in Table 2 below.

[Main ingredients used]
Details of the representative components used in the examples are summarized below.
[Solid particles]
Finely divided anion-modified cellulose fibers (prepared in Preparation Example 3)
Graphene oxide (10 mg/mL aqueous dispersion): manufactured by Tokyo Chemical Industry Co., Ltd. Nanodiamond (particle diameter: <10 nm) (carboxylic acid group modified): manufactured by Tokyo Chemical Industry Co., Ltd. Silica microparticles 1, Aerosil 300: manufactured by Nippon Aerosil Co., Ltd. Silica microparticles 2 (average particle diameter 400 nm): synthesized in Preparation Example 4 [Reagents used in Preparation Example 4]
Ethanol (99.5%): Fujifilm Wako Pure Chemical Industries, Ltd. Tetraethoxysilane: Fujifilm Wako Pure Chemical Industries, Ltd.
28% ammonia water: Fujifilm Wako Pure Chemical Industries, Ltd. [oil solution]
Silicone oil 10cs: Shin-Etsu Chemical Co., Ltd., KF-96-10cs
Silicone oil 100cs: Shin-Etsu Chemical Co., Ltd., KF-96-100cs
Liquid paraffin: Fujifilm Wako Pure Chemical Industries, Ltd. [organic compound with bonding properties]
Amino-modified silicone: Dow Toray SS-3551
Oleylamine: Fujifilm Wako Pure Chemical Industries, Ltd. [surfactant]
Emulgen 109P (polyoxyethylene lauryl ether): manufactured by Kao Corporation [polyether-modified silicone]
Polyether-modified silicone 1: KF-640 manufactured by Shin-Etsu Chemical Co., Ltd.
Polyether-modified silicone 2: KF-642 manufactured by Shin-Etsu Chemical Co., Ltd.
[Polymer compound]
Styrene acrylic: NeoCryl XK-188 (solid content 44.5% by mass) manufactured by DSM
[Volatile organic compounds]
N-methylpyrrolidone: Fujifilm Wako Pure Chemical Industries, Ltd.

[Snow adhesion test]
<Preparation of dry film>
Example 7
2.4 mL of the hard surface treatment agent prepared in Preparation Example 5 was applied to a glass substrate (10 cm × 10 cm × 5 mm thick) and dried at 1 atmosphere, 25°C, and approximately 40% RH for 24 hours to prepare a film, which was used as the substrate of Example 7. The water droplet sliding angle of this film was 7°.

Comparative Example 3
In Comparative Example 3, a glass substrate (10 cm x 10 cm x 5 mm thick) that was not coated with a hard surface treatment agent was used.

Comparative Example 4
In Comparative Example 4, a commercially available anti-snow paint, "Kansai Paint's Easy Snow Paint," was spread with a brush on the same glass substrate as used in Comparative Example 3, and dried for 24 hours at 1 atmosphere, 25°C, and a humidity of approximately 40% RH. The thickness of the paint after drying was 20 μm.

<Snow sliding evaluation>
The snow sliding performance was evaluated in the low temperature test chamber (1°C) of MTS Snow and Ice Research Institute.
A 1 cm x 2 cm x 2 mm thick stainless steel piece was attached to the back of each of the substrates of Example 7 and Comparative Examples 3 and 4 with double-sided tape (Scotch Super Strong Double-Sided Tape, Super Multipurpose, 12 mm wide, manufactured by 3M), and the substrate was placed at a 90° angle on a fixed stand equipped with a magnet. Artificial snow was then blown onto the front of the substrate at a wind speed of 5 m/s for 30 minutes to evaluate snow sliding properties. On the substrate of Example 7, snow slid off within 10 minutes of the start of spraying, whereas on the substrates of Comparative Examples 3 and 4, snow did not slide off within 30 minutes. In other words, it was found that the substrates coated with the hard surface treatment agent of Example 7 had excellent snow sliding properties.

[Flow Resistance Test]
<Preparation of dry film>
Example 8
The hard surface treatment agent prepared in Preparation Example 5 was applied to a SUS304 substrate (L 200 mm × W 50 mm × T 3 mm) and dried at 1 atmosphere, 25°C, and approximately 40% RH for 24 hours to prepare a film, which was used as the substrate of Example 8. The thickness of the dried film was 20 μm.

Example 9
An acrylic resin paint (SEAFLO NEO CF Z, manufactured by Chugoku Paint Co., Ltd.) was spread on a SUS304 substrate (L 200 mm × W 50 mm × T 3 mm) with a brush and dried for 24 hours at 1 atmosphere, 25°C, and approximately 40% RH. The paint thickness after drying was 20 μm. Next, the hard surface treatment agent prepared in Preparation Example 9 was applied thereon and dried in the same manner to form a film, which was used as the substrate of Example 9. The film thickness of the dried film was 20 μm.

Example 10
A substrate was prepared in the same manner as in Example 9, except that an epoxy resin paint (Banno 500, manufactured by Chugoku Paint Co., Ltd.) was used instead of the acrylic resin paint, and the hard surface treatment agent prepared in Preparation Example 9 was applied onto the epoxy resin paint to prepare the substrate of Example 10. The thickness of the dried film was 20 μm.

Comparative Example 5
In Comparative Example 5, a SUS304 substrate (200 mm long x 50 mm wide x 3 mm thick) was used, to which no paint or treatment agent was applied.

Comparative Example 6
In Comparative Example 6, a SUS304 substrate (L 200 mm × W 50 mm × T 3 mm) that had not been coated with any paint or treatment agent was used, which had been coated with an acrylic resin paint (SEAFLO NEO CF Z, manufactured by Chugoku Paint Co., Ltd.) and dried.

Comparative Example 7
In Comparative Example 7, a SUS304 substrate (L 200 mm x W 50 mm x T 3 mm) that had not been coated with any paint or treatment agent was used, which had been coated with an epoxy resin paint (Banno 500, manufactured by Chugoku Paint Co., Ltd.) and dried.

Comparative Example 8
In Comparative Example 8, a PVC (polyvinyl chloride) substrate (L 200 mm x W 50 mm x T 3 mm) without any coating or treatment agent was used.

<Flow resistance measurement>
As shown in Figure 1, pressure loss was measured when tap water (viscosity at 30°C: 0.8 mPa·s) was flowed through a slit flow channel device made of SUS304. A 4 mm thick PTFE (polytetrafluoroethylene) spacer was sandwiched between substrates (Examples 8-10, Comparative Examples 5-8). The distance between pressure ports was 230 mm, the slit width was 30 mm, the slit height was 4 mm, and the flow rate was 13.3 L/min. Transparent tubes were connected to the inlet and outlet pressure ports. A tap was connected to the liquid supply port with a hose at room temperature of 20°C and water temperature of 32°C. Pressure loss was measured by measuring the difference in water surface height in the silicone tubes connected to the inlet and outlet, and the pressure loss was evaluated. The results are shown in Table 3.

[Measurement of film surface roughness]
The surface roughness (Rz) of the film was measured using a laser microscope (Keyence Corporation, VK-9710) under the following measurement conditions: objective lens: 10x, light intensity: 3%, brightness: 1548, Z pitch: 0.5 μm. Rz was measured at five points using the built-in image processing software, and the average value was used.

Table 3 shows that the substrates of Examples 8 to 10 had lower pressure loss values than the substrates of Comparative Examples 5 to 8. This indicates that the substrates coated with the hard surface treatment agents of Examples 8 to 10 have the effect of reducing flow resistance. Furthermore, since the hard surface treatment agent was applied to the substrate of Comparative Example 5 in Example 8, the substrate of Comparative Example 6 in Example 9, and the substrate of Comparative Example 7 in Example 10, it was found that the present invention can impart the effect of reducing flow resistance to various types of substrates. Furthermore, although the surface roughness of Example 9 and Comparative Example 8 was similarly low, it was found that Example 9 was able to reduce pressure loss even more.

[Flow resistance durability test]
Seawater from the vicinity of Shimotsu Port in Wakayama Prefecture was pumped into a circulating water tank, and half of the seawater was replaced once every two weeks in an environment exposed to sunlight. The substrates of Example 9 and Comparative Example 6 were immersed in this condition for seven months, and the state of contamination and the rate of reduction in pressure loss were evaluated three and seven months later.
The evaluation criteria for the fouling state were as follows, and the pressure loss reduction rate was based on the initial value of Comparative Example 6. The results are shown in Table 4.
The lower the score, the better the fouling condition, and the higher the pressure loss reduction rate, the greater the effect of reducing pressure loss, i.e., the greater the effect of reducing flow resistance.

<Stain evaluation>
1: Adherence is less than 10% of the entire surface 2: Adherence is between 10% and 30% of the entire surface 3: Adherence is between 30% and 50% of the entire surface 4: Adherence is between 50% and 70% of the entire surface 5: Adherence is between 70% and 90% of the entire surface 6: Adherence is more than 90% of the entire surface

The following was found from Table 4: Compared to Comparative Example 6, Example 9 was more effective at inhibiting fouling when immersed in circulated seawater, and was even more effective at reducing pressure loss after three and seven months of immersion. Furthermore, while Comparative Example 6 experienced a 44% deterioration in pressure loss over seven months, Example 9 only experienced a 6.2% deterioration from the initial period, demonstrating that the substrate coated with the hard surface treatment agent of Example 9 has a highly durable pressure loss reduction effect, i.e., a highly durable flow resistance reduction effect.

[Aquatic organism adhesion test]
Example 11
1.5 mL of the hard surface treatment agent prepared in Preparation Example 6 was applied to an SUS304 substrate (L 50 mm × W 50 mm × T 3 mm) and dried at 1 atmosphere, 25°C, and approximately 40% RH for 24 hours to prepare a film, which was used as the substrate of Example 11. The water droplet sliding angle of this film was 6°.

Comparative Example 9
An untreated SUS304 substrate having dimensions of L 50 mm x W 50 mm x T 3 mm was used as Comparative Example 9.

Each of the above substrates was connected with a chain and placed in seawater near Shimotsu Port in Wakayama Prefecture at a depth of 2m below the water surface at low tide, and an immersion test in seawater was conducted for three months.

Three months after immersion, the degree of adhesion of crustaceans and algae to the substrate was visually evaluated. No adhesion of crustaceans was observed on the substrate of Example 11, the area of adhesion of algae was less than 30% of the substrate, and the attached aquatic organisms could be easily removed by rinsing with water. On the other hand, on the substrate of Comparative Example 9, crustaceans were attached to more than 30% of the substrate area, and algae were attached to more than 80%. These organisms could not be removed without repeated rubbing with a tool. In other words, it was found that the substrate coated with the hard surface treatment agent of Example 11 was excellent in inhibiting the adhesion of aquatic organisms and in removing attached aquatic organisms.

[Antibacterial test]
<Preparation of dry film>
Example 12
0.4 mL of the hard surface treatment agent prepared in Preparation Example 7 was applied to a glass substrate (Micro Slide Glass S2112, manufactured by MATSUNAMI Co., Ltd.) and dried at 1 atmosphere, 25°C, and approximately 40% RH for 24 hours to prepare a film, which was used as the substrate of Example 12. The water droplet sliding angle of this film was 5°.

Comparative Example 10
In Comparative Example 10, a glass substrate (Micro Slide Glass S2112 manufactured by MATSUNAMI Co., Ltd.) to which no treatment agent was applied was used.

<Preparation of bacterial solution>
A glycerol stock solution of Staphylococcus aureus (NBRC13276) was pre-cultured at 37°C for 24 hours using Luria-Bertani Agar (manufactured by Nippon Pharmaceutical Co., Ltd., LB agar medium "Daigo").
10 mL of Luria-Bertani (manufactured by Nippon Pharmaceutical Co., Ltd., LB medium "Daigo") was placed in a 50 mL centrifuge tube, and one loopful of the colony produced in the pre-culture was inoculated into the tube and cultured with shaking at 37°C, 200 rpm, for 24 hours.
After cultivation, the absorbance at a wavelength of 600 nm (OD600nm) was measured using a spectrophotometer (Funakoshi Co., Ltd., WPA biowave CO8000), and the bacterial solution diluted to an absorbance of 0.4 was diluted 100-fold with LB medium to prepare the bacterial solution for evaluation.

<Evaluation of biofilm formation inhibitory effect ~ Colony count method ~>
The substrates of Example 12 and Comparative Example 10 were irradiated with UV light for 10 minutes to sterilize the substrate surface. The sterilized substrates were placed in a square 4-well dish (AS ONE Corporation, Multi-Dish for Suspension Cells 267061), and 6 mL of the previously prepared bacterial solution was added to each well. The substrates were then cultured at 37°C for 24 hours to form a biofilm on the substrate.
The bacterial suspension in the wells was aspirated using a pipette gun, and 6 mL of saline was added to the well and shaken. The saline was then aspirated using a pipette gun, and 6 mL of saline was added to the well and shaken. The saline was then aspirated using a pipette gun, and the surface of the substrate (15 ^cm² ) was wiped with a swab test kit (Elmex, ST-25). The bacteria were extracted in 10 mL of phosphate-buffered saline and diluted 10-fold with diluent (LP diluent "Daigo", Nippon Pharmaceutical Co., Ltd.). A serial dilution method was used to prepare bacterial suspensions, and 100 μL was spread on LB agar medium using plating beads (Fujifilm Wako Pure Chemical Industries, Bac 'n' Roll Beads) and cultured at 30°C for 48 hours.
Colonies confirmed to have grown on the agar medium after the culture were counted to determine the number of bacteria attached to the test plate. It was found that the substrate of Example 12 inhibited bacterial attachment by 98% compared to the glass substrate of Comparative Example 10. In other words, it was found that the substrate coated with the hard surface treatment agent of Example 12 had excellent antibacterial properties.

[Mold Releasability Test]
<Preparation of dry film>
Example 13
3 g of the hard surface treatment agent prepared in Preparation Example 8 was uniformly applied to a deep stainless steel tray (manufactured by Sanbo Co., Ltd., external dimensions: 135 × 106 × H 59 mm, volume 650 mL) using an air spray (manufactured by Anest Iwata, WIDER1-10E1G, nozzle diameter Φ1.0 mm), and dried for 1 hour at 1 atmosphere, 25°C, and a humidity of approximately 40% RH to prepare a film, which was used as the tray of Example 13. The film thickness was 7 μm, and the water droplet sliding angle of this film was 10°.

Comparative Example 11
In Comparative Example 11, a stainless steel deep tray (manufactured by Sanpo Co., Ltd., external dimensions: 135 x 106 x H59 mm, volume: 650 mL) to which no treatment agent was applied was used.

Comparative Example 12
In Comparative Example 12, 3 g of a commercially available silicone-based release agent (KM-9782, manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient 10%) was uniformly applied using an air spray (WIDER1-10E1G, manufactured by Anest Iwata, nozzle diameter Φ1.0 mm) to a deep stainless steel tray (manufactured by Sanpo Co., Ltd., external dimensions: 135 × 106 × H59 mm, volume 650 mL) that had not been coated with a treatment agent, and the coating was dried for 1 hour at 1 atmosphere, 25°C, and a humidity of approximately 40% RH to produce a film.

<Evaluation of resin release properties>
An amorphous polyester resin (Vylon 600™, manufactured by Toyobo Co., Ltd.) placed in a stainless steel container was softened on a hot plate heated to 300°C, and 500 g of the resin was poured into a deep stainless steel tray treated with the coating agent of Example 13 or Comparative Example 12, or into an untreated deep stainless steel tray (Comparative Example 11). The resin was cooled at room temperature for 12 hours to harden, and then the releasability of the resin was evaluated according to the following criteria.
With the bat of Example 13, the resin fell off simply by turning the bat upside down, and the same release properties were maintained even after the same experiment was repeated 10 times. On the other hand, with the bat of Comparative Example 12, it was necessary to hit the bottom of the bat with a hammer to release the resin. With the bat of Comparative Example 11, the resin did not release even after being hit with a hammer five times. In other words, it was found that the bat coated with the hard surface treatment agent of Example 13 had excellent release properties.

In summary, it has been found that the coating formed by applying the hard surface treatment agent of the present invention to a substrate and drying it has excellent antifouling properties due to its synovial properties, and also has excellent effects in inhibiting the adhesion of aquatic organisms in the sea, inhibiting the adhesion of snow (snow prevention effect), antibacterial properties, and resin release properties.

The hard surface treatment agent of the present invention has snow-proofing, antifouling, antibacterial, flow resistance-reducing, and release-improving effects, and can therefore be used as snow-proof paint, antifouling paint, antibacterial paint, flow resistance-reducing agent, release agent, etc.

PG pressure gauge

Claims (5)

A hard surface treatment agent containing an oil-in-water Pickering emulsion ,
The hard surface treatment agent, wherein the emulsion contains solid particles to which an organic compound having a binding ability to the solid particles is bound, wherein the solid particles are anionic solid particles, and the organic compound having a binding ability is an organic compound having a cationic functional group . 2. The hard surface treatment agent according to claim 1 , wherein the organic compound having a cationic functional group is an organic compound having an amino group. 3. The hard surface treatment agent according to claim 1, wherein the anionic solid particles are inorganic particles or crystalline organic particles. The hard surface treatment agent according to any one of claims 1 to 3 , wherein the anionic solid particles are at least one selected from the group consisting of anion-modified cellulose fibers having an I-type crystal structure, silica particles, and carbon-based compounds having an anionic group. The hard surface treatment agent according to any one of claims 1 to 4 , which is used as an anti-snow paint, an antifouling paint, an antibacterial paint, a flow resistance reducing agent, or a mold release agent.