JP7773364B2 - Method for forming a laminate - Google Patents

Description

The present invention relates to a method for forming a laminate.

Anti-fouling paint compositions have been known for some time that form anti-fouling coating films that have a certain degree of wear and exhibit excellent anti-fouling properties over a long period of time in order to prevent aquatic organisms from attaching to the bottom of ships (Patent Document 1).

International Publication No. 2011-118526

A laminate coated with such an antifouling coating composition can maintain a clean surface free of deposits by dissolving the coating film itself, even if only a small amount of deposits are attached.
However, once organisms with strong adhesive power, such as barnacles, attach to the surface, they are difficult to remove and ultimately must be removed using tools. Removing barnacles using tools requires a great deal of effort, and there are also issues with exposing the base material of the laminate, resulting in a decrease in performance and a deterioration in appearance.

Therefore, the object of the present invention is to provide a method for forming a laminate that allows for easy removal of adhesions even when organisms with strong adhesive properties, such as barnacles, are attached.

The present invention relates to the following [1] and [2].
[1] A method for forming a laminate, comprising the following steps 1 and 2:
Step 1: A step of applying an emulsion composition containing the following components (A) to (C) onto a resin surface: (A) cellulose fibers having a modified group; (B) water; and (C) an organic compound that is non-volatile at 25°C and 1 atmosphere. Step 2: A step of drying the emulsion composition after Step 1. [2] The method for forming a laminate according to [1] above, wherein the resin is a soluble resin.

The present invention provides a method for forming a laminate that allows for easy removal of adhesions, even when organisms with strong adhesive properties, such as barnacles, are attached.

FIG. 1 is a schematic diagram showing the cross-sectional structure of a laminate according to the present invention.

1. Laminate The laminate in this specification is a structure in which a film formed by drying an emulsion composition is laminated on a resin surface. The laminate in this specification may further be formed on a substrate. For example, as shown in Figure 1, a structure in which "substrate 1 - resin layer 2 - film 3" are laminated can be mentioned.
Furthermore, in the laminate herein, any film may be formed on the surface of the film formed by drying the emulsion composition, or any film may be formed between the film and the resin layer, or between the substrate and the resin layer.

The laminate of the present invention has a film with synovial properties on its surface, and can therefore be used as components that come into contact with seawater or freshwater, such as ship hulls and propellers, bridge frameworks, piping, quays, cooling towers, tank interior surfaces, offshore facilities and observation equipment, and fishing nets.

<Resin layer>
The resin layer is a layer formed from a resin, and preferably contains a soluble resin.
The thickness of the resin layer is preferably 1 μm or more, more preferably 10 μm or more, and even more preferably 50 μm or more from the viewpoint of easily removing deposits from the film, and is preferably 1 mm or less, more preferably 500 μm or less, and even more preferably 200 μm or less from the viewpoint of improving productivity.

The resin layer may contain optional components that do not impair the effects of the present invention.

[Dissolved resin]
The soluble resin is a material for the resin layer, and is preferred because the use of the soluble resin allows for easy peeling and renewal of the resin layer or film from the substrate.

Resins that are soluble when in contact with flowing water are defined as "soluble resins" in this specification. In the emulsion composition of the present invention, soluble resins play a role in improving the durability of the synovial fluid properties of the membrane and renewing the membrane surface by dissolving.

In the present invention, the use of a soluble resin is preferred because it allows for stable coating wear resistance on ships, underwater structures, etc.

The soluble resin is a metal salt bond-containing copolymer (d1) (hereinafter also referred to as "copolymer (d1)") described below.
Metal salt bond-containing copolymer (d2) (hereinafter also referred to as "copolymer (d2)"), and Silyl ester copolymer (d3) (hereinafter also referred to as "copolymer (d3)")
Preferably, the resin contains one or more soluble resins selected from the group consisting of:
The soluble resin may be a copolymer that satisfies the requirements of both copolymers (d1) and (d2), containing both the side chain terminal type metal salt bond structure found in copolymer (d1) and the cross-linked type metal salt bond structure found in copolymer (d2).
The soluble resins may be used alone or in combination of two or more.

[Metal Salt Bond-Containing Copolymer (d1)]
The metal salt bond-containing copolymer (d1) is an acrylic resin or polyester resin, and is a metal salt bond-containing copolymer having a side chain terminal group represented by general formula (DI). In this specification, the structure may be referred to as a "side chain terminal type metal salt bond."
-COO-M-O-COR ¹ (DI)
(In formula (DI), M represents zinc or copper, and ^R1 represents an organic group. When copolymer (d1) has a plurality of side chain terminal groups represented by formula (DI), each ^R1 and M may be the same or different.)

The organic group R ¹ in the copolymer (d1) (and the organic group R ¹ in the formula (D-IV) described later) is an organic acid residue formed from a monobasic acid, and is preferably a saturated or unsaturated aliphatic hydrocarbon group having from 2 to 30 carbon atoms, a saturated or unsaturated alicyclic hydrocarbon group having from 3 to 20 carbon atoms, or an aromatic hydrocarbon group having from 6 to 18 carbon atoms, or a substituted product thereof. Examples of the substituted product include a hydroxyl group-substituted product.

Among the copolymers (d1), acrylic resin-type polymers are preferred. Such acrylic resin-type polymers can be prepared, for example, by polymerization using a monomer having a metal salt bond represented by general formula (D-IV), i.e., a monobasic acid metal (meth)acrylate (hereinafter also referred to as "monomer (d11)").
CH ₂ =C(R ² )-COO-MO-COR ¹ (D-IV)
(In formula (D-IV), M is zinc or copper, ^R1 is an organic group, and ^R2 is a hydrogen atom or a methyl group. ^R1 in formula (D-IV) and its preferred types are the same as the organic group ^R1 in formula (DI). However, in order to distinguish it from the monomer (d21) represented by formula (D-II) which can form a cross-linked metal salt bond described later, a vinyl group [—CH═CH ₂ ] and an isopropenyl group [—C(CH ₃ )═CH ₂ ] are excluded from ^R1 in formula (D-IV).)

Copolymer (d1) may be a polymer obtained by a copolymerization reaction of two or more types of monomer (d11). It may also be a polymer obtained by a copolymerization reaction of one or more types of monomer (d11) and one or more other unsaturated monomers copolymerizable with monomer (d11) (hereinafter also referred to as "monomer (d12)"), i.e., a copolymer having component units derived from monomer (d11) and component units derived from monomer (d12).

Monomer (d12) can be appropriately selected from various compounds used as polymerizable unsaturated monomers for acrylic resins. For example, monomers that do not contain a metal salt bond, such as alkyl (meth)acrylate, alkoxyalkyl (meth)acrylate, and hydroxyalkyl (meth)acrylate, are preferred. Among these, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate are more preferred.

The acrylic resin type copolymer (d1) can also be prepared by a method in which, for example, an acrylic resin is prepared using (meth)acrylic acid, an alkyl (meth)acrylate, an alkoxyalkyl (meth)acrylate, a hydroxyalkyl (meth)acrylate, or the like, and then a reaction is carried out to introduce a structure in which an organic group (R ¹ ) is bonded via zinc or copper (M) to a carboxy group in the side chain of the acrylic resin that has not yet formed a metal salt bond, thereby forming a side chain terminal group represented by the formula (DI).

Even when a predetermined side chain terminal group is introduced into the acrylic resin by the above-mentioned preparation method, the preferred types of R ¹ in the above-mentioned formula (DI) are the same as those described above. In the above-mentioned preparation method, the above-mentioned monobasic acid can be used in the reaction for introducing the organic group R ¹ .

In copolymer (d1), the content of zinc and/or copper resulting from the structure of formula (D-I) is preferably 0.5% by mass or more and 20% by mass or less of the copolymer. By using copolymer (d1) that satisfies these conditions, it becomes possible to form an antifouling coating film that is even better in both antifouling properties and wear resistance. Here, "content of zinc and/or copper" means the total content of zinc and copper when both zinc and copper are present.

The zinc and/or copper content can be adjusted to fall within the above range by adjusting the blending ratio of the monomer (d11) containing these metals and the other monomer (d12) used in preparing the copolymer (d1), or by adjusting the amount of the zinc and/or copper-containing compound (e.g., the monobasic acid) added to the acrylic resin afterwards to react with it.

[Metal Salt Bond-Containing Copolymer (d2)]
The metal salt bond-containing copolymer (d2) is a copolymer having a component unit derived from a monomer (d21) represented by general formula (D-II) and a component unit derived from another unsaturated monomer (d22) copolymerizable with the monomer (d21).

CH ₂ =C(R ² )-COO-M-O-CO-C(R ² )=CH ₂ (D-II)
(In formula (D-II), M represents zinc or copper, and ^R2 represents a hydrogen atom or a methyl group. When copolymer (d2) contains a plurality of component units derived from monomer (d21) represented by formula (D-II), each ^R2 and M may be the same or different.)

Examples of monomer (d21) include zinc diacrylate, zinc dimethacrylate, copper diacrylate, and copper dimethacrylate. Monomer (d21) may be used alone or in combination of two or more types.

Monomer (d21) can be prepared by a known method, for example, by heating and stirring an inorganic metal compound (e.g., zinc or copper oxide, hydroxide, or chloride) and (meth)acrylic acid or an ester compound thereof in the presence of an alcohol-based organic solvent and water at a temperature below the decomposition temperature of the metal salt.

The component unit derived from monomer (d21) has a structure represented by the following general formula, and in this specification, this structure is sometimes referred to as a "bridged metal salt bond."

As with monomer (d12) for copolymer (d1) described above, the other unsaturated monomer (d22) copolymerizable with monomer (d21) can be appropriately selected from the various compounds used as polymerizable unsaturated monomers for acrylic resins. That is, preferred unsaturated monomers (d22) include alkyl (meth)acrylates, alkoxyalkyl (meth)acrylates, and hydroxyalkyl (meth)acrylates. Among these, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate are more preferred.

The monomer (d11) for the copolymer (d1), i.e., the monobasic metal (meth)acrylate represented by the formula (D-IV), is also a monomer copolymerizable with the monomer (d21) and corresponds to the unsaturated monomer (d22) that can be used to prepare the metal salt bond-containing copolymer (d2). ^R1 and its preferred embodiments in the monobasic metal (meth)acrylate represented by the formula (D-IV) as the unsaturated monomer (d22) are the same as the organic group ^R1 in formula (DI).
The unsaturated monomer (d22) may be used alone or in combination of two or more kinds.

It is also preferable that the unsaturated monomer (d22) contains a monobasic metal (meth)acrylate represented by the formula (D-IV) and one or more unsaturated monomers selected from the group consisting of alkyl (meth)acrylates, alkoxyalkyl (meth)acrylates, and hydroxyalkyl (meth)acrylates.

Other examples of the unsaturated monomer (d22) include styrene and styrene derivatives; vinyl esters such as vinyl acetate and vinyl propionate; (meth)acrylamide and its derivatives; and (meth)acrylonitrile.

For copolymer (d2), from the same viewpoint as for copolymer (d1), the content of zinc and/or copper resulting from the structure of formula (D-II) is preferably 0.5% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 19% by mass or less, of the copolymer. Here, "content of zinc and/or copper" means the total content of zinc and copper when both zinc and copper are present.

The zinc and/or copper content can be adjusted by the blending ratio of the monomers used in preparing copolymer (d2). When copolymer (d2) has both a cross-linked metal salt bond structure and a side chain terminal metal salt bond structure, it is preferable that the total zinc and/or copper content attributable to each structure be within the above range.

The number-average molecular weight and weight-average molecular weight of copolymer (d1) and copolymer (d2) can be appropriately adjusted taking into consideration the viscosity and storage stability of the antifouling coating composition, the dissolution rate of the antifouling coating film, etc., but the number-average molecular weight is preferably from 1,000 to 100,000, more preferably from 1,000 to 50,000, and the weight-average molecular weight is preferably from 1,000 to 200,000, more preferably from 1,000 to 100,000.
The number average molecular weight and weight average molecular weight in this specification are values determined by gel permeation chromatography using polystyrene as a standard substance.

[Silyl ester copolymer (d3)]
The silyl ester copolymer (d3) is a copolymer having a component unit (hereinafter also referred to as a "silyl ester component unit") derived from a monomer (d31) represented by general formula (D-III) (hereinafter also referred to as a "silyl ester monomer"), and optionally having a component unit derived from another unsaturated monomer (d32) copolymerizable with the monomer (d31).

R ⁷ -CH=C(R ³ )-COO-SiR ⁴ R ⁵ R ⁶ (D-III)
(In formula (D-III), ^R3 is a hydrogen atom or a methyl group, ^R4 , ^R5 , and ^R6 are each independently a hydrocarbon group, ^R7 is a hydrogen atom or ^R8 -O-CO- (wherein ^R8 is an organic group or ^a silyl group represented by ^SiR9R10R11 , ^{and R9 , R10} , and ^R11 are each independently a hydrocarbon group).

When R ⁷ in the silyl ester monomer (d31) is a hydrogen atom, the monomer is represented by the general formula (D-IIIa).
CH ₂ =C(R ³ )-COO-SiR ⁴ R ⁵ R ⁶ (D-IIIa)
(In formula (D-IIIa), R ³ , R ⁴ , R ⁵ and R ⁶ are the same as R ³ , R ⁴ , R ⁵ and R ⁶ in formula (D-III), respectively.) The hydrocarbon groups in R ⁴ , R ⁵ and R ⁶ are preferably alkyl groups having 1 to 10 carbon atoms, and more preferably alkyl groups such as methyl, ethyl, propyl and isopropyl.

When R ⁷ of the silyl ester monomer (d31) is “R ⁸ —O—CO—”, the monomer is represented by the general formula (D-IIIb).
R ⁸ -O-CO-CH=C(R ³ )-COO-SiR ⁴ R ⁵ R ⁶ (D-IIIb)
(R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁸ in formula (D-IIIb) are the same as R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁸ in formula (D-III) or formula (D-IIIa), respectively. The organic group for R ⁸ is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group such as methyl, ethyl, propyl or isopropyl. The hydrocarbon group for R ⁹ , R ¹⁰ and R ¹¹ is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group such as methyl, ethyl, propyl or isopropyl.)

The silyl ester monomer (d34) represented by the formula (D-IIIb) includes, for example, maleic acid ester (in the formula (D-IIIb), R ³ =hydrogen atom).

Other unsaturated monomers (d32) that can be copolymerized with monomer (d31) (or monomers (d33) and/or (d34)) include the "other unsaturated monomers (d12) and (d22)" exemplified as raw material compounds for the copolymers (d1) and (d2).

The silyl ester monomer (d31) may be used alone or in combination of two or more types. Furthermore, the other unsaturated monomer (d32) may be used alone or in combination of two or more types.

In the silyl ester copolymer (d3), the component units derived from the silyl ester monomer (d31) are preferably contained in an amount of 10 mol % to 100 mol % in the copolymer (total constituent units 100 mol %), and the component units derived from other unsaturated monomers (d32) are contained in the remaining amount, i.e., preferably 0 mol % to 90 mol %. A component unit content within this range is preferable in terms of excellent resin viscosity in the coating film (e.g., crack resistance), storage stability of the paint, and resin elution in the coating film.

The number average molecular weight of the silyl ester copolymer (d3) is preferably 1,000 or more and 200,000 or less (two hundred thousand). A number average molecular weight within this range is preferable in that it provides excellent resin viscosity in the coating film (e.g., crack resistance), storage stability of the paint, and elution of the resin in the coating film.

<Film formed by drying emulsion composition>
The film formed by drying the emulsion composition containing components (A), (B), and (C) has synovial properties, and therefore can impart synovial properties to the laminate. Such a film is formed by drying the emulsion composition described below.

From the viewpoint of easy removal of deposits, the thickness of the film is preferably 0.1 μm or more, more preferably 1 μm or more, and even more preferably 10 μm or more. From the viewpoint of improving productivity, the thickness is preferably 10 mm or less, more preferably 1 mm or less, and even more preferably 100 μm or less. The desired film thickness can be achieved by adjusting the coating thickness during spraying and the proportion of the medium. The film thickness can be measured according to the method described in the Examples below.

[Component (A)]
Component (A) is a cellulose fiber having a modified group.
A preferred example of a cellulose fiber having a modifying group is a modified cellulose fiber in which a modifying group is bonded to one or more groups selected from the group consisting of anionic groups and hydroxy groups of an anion-modified cellulose fiber having a type I crystal structure.

[Anion-modified cellulose fiber]
Anion-modified cellulose fibers are cellulose fibers modified to contain anionic groups. Anion-modified cellulose fibers have a cellulose type I crystal structure derived from the raw cellulose fibers. 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. Furthermore, 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.

In this specification, the degree of crystallinity of various cellulose fibers refers to the degree of 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. Cellulose type I refers to the crystalline form of natural cellulose, and cellulose type I crystallinity refers to the proportion of crystalline regions in the entire cellulose fiber. The presence or absence of cellulose type I crystalline structure can be determined by the presence of a peak at 2θ = 22.6° in X-ray diffraction measurement.

Examples of the anionic group contained in the anion-modified cellulose fiber include a carboxy group, a sulfonic acid group, and a phosphate group. From the viewpoint of the efficiency of introducing the modifying group into the cellulose fiber, the anionic group is preferably a carboxy group. Examples of the ion (counter ion) that is paired with the anionic group in the anion-modified cellulose fiber 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 substituting these metal ions with an acid.
As the anion-modified cellulose fiber, a carboxy group-containing cellulose fiber in which the anionic group is a carboxy group is more preferred from the viewpoints of ease of preparation and mild reaction conditions.

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.

From the viewpoint of ease of handling, the average fiber diameter of the anion-modified cellulose fiber is preferably 0.1 nm or more, more preferably 1.0 nm or more, and even more preferably 2.0 nm or more. From the viewpoint of strength when formed into a film, the average fiber diameter is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. The average fiber diameter of the anion-modified cellulose fiber is measured by the method described in the Examples below.

[Modified cellulose fiber]
Cellulose fibers having a modifying group are also referred to herein as modified cellulose fibers. From the viewpoint of easily removing deposits from the membrane, the modified cellulose fibers are preferably anion-modified cellulose fibers in which the modifying group is bonded to an anionic group or a hydroxyl group. The modifying group is introduced by reacting the anion-modified cellulose fiber with a compound for introducing the modifying group (referred to herein as a "modifying compound"). That is, the structure of the modifying group depends on the structure of the modifying compound used.

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

When the bonding site is an anionic group, the bonding mode between the modifying group and the anion-modified cellulose fiber is an ionic bond or a covalent bond. Here, when the bonding mode is an ionic bond, the modifying compound having a cationic group bonds with the anionic group via electrostatic interaction. Here, when the bonding mode is a covalent bond, the two are bonded via an ester bond, amide bond, etc. In particular, when the anionic group is a carboxy group, bonding is via an ester bond, amide bond, carbonate bond, urethane bond, etc.

[Modifying group]
The modifying group may be (a) a polymer group or (b) a hydrocarbon group, from the viewpoint of facilitating removal of deposits from the membrane. One type of these modifying groups may be bonded to the anion-modified cellulose fiber alone, or two or more types may be bonded in combination.

(a) Polymer group The polymer group is a functional group containing a polymer structure. From the viewpoint of easily removing deposits from the film, the functional group equivalent of the polymer group is preferably 100 g/mol or more, more preferably 200 g/mol or more, more preferably 300 g/mol or more, more preferably 400 g/mol or more, even more preferably 600 g/mol or more, even more preferably 800 g/mol or more, and even more preferably 1,500 g/mol or more. From the same viewpoint, it is preferably 16,000 g/mol or less, more preferably 14,000 g/mol or less, even more preferably 12,000 g/mol or less, even more preferably 10,000 g/mol or less, even more preferably 7,000 g/mol or less, even more preferably 5,000 g/mol or less, even more preferably 4,000 g/mol or less, even more preferably 3,500 g/mol or less, and even more preferably 2,500 g/mol or less.
The functional group equivalent is the molecular weight per functional group, and is calculated by functional group equivalent (g/mol)=weight average molecular weight/number of functional groups per molecule.

From the viewpoint of facilitating removal of deposits from the membrane, the weight-average molecular weight of the polymer group is preferably 2,000 or more, more preferably 5,000 or more, and even more preferably 8,000 or more. From the same viewpoint, it is preferably 1,000,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less.

From the viewpoint of easily removing deposits from the film, the polymer group is preferably a functional group having a repeating structure linked by a structure containing oxygen atoms, more preferably a functional group having a repeating structure linked by oxygen atoms, such as a polyoxyalkylene structure or a polysiloxane structure, and more preferably a functional group having a polysiloxane structure.

A polysiloxane structure is a structure with siloxane bonds as the main chain, which may further include alkylene groups. The polysiloxane structure may have a substituent, as described below.

(b) Hydrocarbon Group Examples of the hydrocarbon group include monovalent hydrocarbon groups, such as chain saturated hydrocarbon groups, chain unsaturated hydrocarbon groups, cyclic saturated hydrocarbon groups, and (heterocyclic) aromatic hydrocarbon groups.

From the viewpoint of improving the durability of the synovial fluid performance of the membrane, 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 4 or more, even more preferably 8 or more, even more preferably 12 or more, even more preferably 16 or more, even more preferably 18 or more, and from the same viewpoint, it is preferably 40 or less, more preferably 30 or less, even more preferably 24 or less, even more preferably 22 or less. The hydrocarbon group may have a substituent as described below, and a part of the hydrocarbon group may be substituted with a hydrogen nitride group.
The aromatic hydrocarbon group is, for example, selected from the group consisting of an aryl group and an aralkyl group.

(c) Further Substituents The modifying groups such as (a) polymer groups and (b) hydrocarbon groups may further have a substituent. Examples of the substituent include alkoxy groups having 1 to 6 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, and hexyloxy; methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, and sec-butoxycarbonyl. alkoxycarbonyl groups having 1 to 6 carbon atoms in the alkoxy group, such as a tert-butoxycarbonyl group, a pentyloxycarbonyl group, or an isopentyloxycarbonyl group; halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; acyl groups having 1 to 6 carbon atoms, such as an acetyl group or a propionyl group; aralkyl groups; aralkyloxy groups; alkylamino groups having 1 to 6 carbon atoms; dialkylamino groups having an alkyl group with 1 to 6 carbon atoms; and a hydroxy group.

The bond amount (mmol/g) and introduction rate (mol%) of modifying groups in modified cellulose fibers refer to the amount and proportion of modifying groups introduced into the modified cellulose fibers. The bond amount and introduction rate of modifying groups can be adjusted by the amount and type of modifying compound added, reaction temperature, reaction time, solvent, etc.

The amount of modifying groups bonded to the modified cellulose fiber is preferably 0.1 mmol/g or more, more preferably 0.2 mmol/g or more, and even more preferably 0.5 mmol/g or more, from the viewpoint of easy removal of deposits from the membrane. Furthermore, from the viewpoint of reactivity, it is preferably 3 mmol/g or less, more preferably 2.5 mmol/g or less, and even more preferably 2 mmol/g or less.

In addition, from the viewpoint of easily removing deposits from the membrane, the introduction rate of the modifying group in the modified cellulose fiber is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 40 mol% or more, and even more preferably 50 mol% or more. From the viewpoint of reactivity, it is preferably 99 mol% or less, more preferably 97 mol% or less, even more preferably 95 mol% or less, and even more preferably 90 mol% or less.

[Method for manufacturing modified cellulose fibers]
The modified cellulose fiber can be produced, for example, by a method comprising the steps of: (1) introducing anionic groups into raw cellulose fiber to obtain anionically modified cellulose fiber; and (2) binding a modifying compound to the anionically modified cellulose fiber obtained by the method comprising step (1) to obtain the modified cellulose fiber.

(1) Step of Obtaining Anion-Modified Cellulose Fiber The anion-modified cellulose fiber used in the present invention can be obtained by subjecting raw cellulose fiber to an oxidation treatment or an anionic group addition treatment to introduce one or more anionic groups to thereby anion-modify the fiber.

Cellulose fibers to be anionically modified, i.e., cellulose fibers used as raw materials for modified cellulose fibers and anionically modified cellulose fibers, are preferably natural cellulose fibers from an environmental perspective. Examples include wood pulp such as softwood pulp and hardwood pulp; cotton pulp such as cotton linter and cotton lint; non-wood pulp such as straw pulp and bagasse pulp; and bacterial cellulose. These can be used alone or in combination of two or more.

From the standpoint of ease of handling and cost, the average fiber diameter of the raw cellulose fibers is preferably 1 μm or more, and preferably 300 μm or less.

In addition, from the standpoint of availability and cost, the average fiber length of the raw cellulose fibers is preferably 100 μm or more and preferably 5,000 μm or less. The average fiber diameter and average fiber length of the raw cellulose fibers can be measured according to the method described in the Examples below. From the standpoint of dispersibility, it is preferable to use raw cellulose fibers that have been subjected to a fiber shortening treatment such as alkaline hydrolysis or acid hydrolysis, and have an average fiber length of 1 μm or more and 1,000 μm or less.

Examples of the anionic group that can be introduced include a carboxyl group, a sulfonic acid group, or a phosphate group.

(i) Introducing carboxy groups as anionic groups into cellulose fibers Examples of methods for introducing carboxy groups into cellulose fibers include a method of converting hydroxy groups of cellulose into carboxy groups by oxidizing them, and a method of reacting the hydroxy groups of cellulose with one or more compounds selected from the group consisting of compounds having carboxy groups, acid anhydrides of compounds having carboxy groups, and derivatives thereof.

As a method for oxidizing the hydroxyl groups of the cellulose, for example, a method can be applied in which 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) is used as a catalyst to react with an oxidizing agent such as sodium hypochlorite and a bromide such as sodium bromide. For more details, see known methods, such as the method described in JP 2011-140632 A.

By subjecting cellulose fibers to oxidation treatment using TEMPO as a catalyst, hydroxymethyl groups (—CH ₂ OH) at the C6 position of cellulose structural units are selectively converted to carboxy groups. This method is particularly advantageous in that it exhibits excellent selectivity for the hydroxy group at the C6 position, which is the target of oxidation on the surface of the raw cellulose fibers, and the reaction conditions are mild. Therefore, a preferred embodiment of the anion-modified cellulose fiber of the present invention is a cellulose fiber in which the C6 position of the cellulose structural unit is a carboxy group. In this specification, cellulose fibers obtained by oxidizing hydroxyl groups in cellulose structural units are sometimes referred to as “oxidized cellulose fibers,” and cellulose fibers in which the C6 position of the cellulose structural unit is a carboxy group are sometimes referred to as “TEMPO-oxidized cellulose fibers.” Oxidized cellulose fibers are preferred because they are easier to prepare than other anion-modified cellulose fibers. Therefore, one preferred embodiment of the modified cellulose fiber of the present invention is a modified cellulose fiber in which an amino-modified silicone is bonded to an oxidized cellulose fiber, and one more preferred embodiment is a modified cellulose fiber in which an amino-modified silicone is bonded to a TEMPO-oxidized cellulose fiber.

By further subjecting the oxidized cellulose fibers to a further oxidation treatment or reduction treatment, it is possible to prepare oxidized cellulose fibers from which any remaining aldehyde groups have been removed.

(ii) Introducing sulfonic acid groups or phosphate groups as anionic groups into cellulose fibers Examples of a method for introducing sulfonic acid groups as anionic groups into cellulose fibers include a method in which sulfuric acid is added to cellulose fibers and the fibers are heated.
Methods for introducing phosphate groups as anionic groups into cellulose fibers include mixing a powder or aqueous solution of phosphoric acid or a phosphoric acid derivative with dry or wet cellulose fibers, adding an aqueous solution of phosphoric acid or a phosphoric acid derivative to a dispersion of cellulose fibers, etc. When these methods are employed, dehydration treatment, heat treatment, etc. are generally carried out after mixing or adding a powder or aqueous solution of phosphoric acid or a phosphoric acid derivative.

(2) Step of Obtaining Modified Cellulose Fiber The modified cellulose fiber can be produced by bonding the anion-modified cellulose fiber with one or more compounds selected from the group consisting of a compound having a modifying group, and preferably an amino-modified silicone and a hydrocarbon compound having a cationic group, from the viewpoint of facilitating removal of deposits from the membrane. Such a production method can be a known method, such as the method described in JP 2015-143336 A.

(Modification compound)
From the viewpoint of improving the durability of the synovial fluid performance of the membrane, the modifying compound is a compound that has a modifying group and can bond with anion-modified cellulose fibers, preferably a compound that has a modifying group and can bond with anionic groups or hydroxy groups of anion-modified cellulose fibers, more preferably a compound that has a modifying group and a cationic group, even more preferably a compound that has a modifying group and an amino group or a quaternary ammonium group, and even more preferably a primary amine, secondary amine, tertiary amine or quaternary ammonium compound that has a modifying group.
Preferred examples of the modifying compound include polymer compounds having an amino group and hydrocarbon compounds having a cationic group, from the viewpoint of easily removing deposits from the membrane.

(i) Amino group-containing polymer compounds The amino group-containing polymer compounds preferred as modifying compounds for 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 polymeric compounds having amino groups in the present invention include resins such as amino-modified silicones, polyoxyalkyleneamines, amino-modified poly(meth)acrylate polymers, amino-modified vinyl polymers, amino-modified polyesters, amino-modified polycarbonates, polyallylamine, and polyethyleneimine; chain aliphatic polyamines, cyclic aliphatic polyamines, and alicyclic aromatic polyamines; and the reactive group may be located in the main chain, side chain, or terminal of the polymeric compound. Of these, amino-modified silicones are preferred from the viewpoint of improving the durability of the synovial fluid performance of the membrane.

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 easily removing deposits from the film, 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 easy removal of deposits from the membrane. From the viewpoint of ease of bonding to anion-modified cellulose fibers, it 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 as amino equivalent (g/mol) = weight-average molecular weight / number of nitrogen atoms per molecule. Here, the number of nitrogen atoms can be determined by elemental analysis.

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

[Wherein, 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 easily removing deposits from the film. 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 easily removing deposits from the membrane, 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. From the viewpoint of improving the durability of the synovial fluid performance of the membrane, the weight-average molecular weight of the compound of general formula (a1) is preferably 2,000 or more, more preferably 5,000 or more, and even more preferably 8,000 or more. From the same viewpoint, it is preferably 1,000,000 or less, more preferably 100,000 or less, and even more preferably 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 easily removing deposits from the film, the amino-modified silicone is preferably at least one selected from the group consisting of monoamino-modified silicones having one amino group in one side chain B and diamino-modified silicones having two amino groups in one 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 silicone-based compound may have a substituent. Specific examples of the substituent include those described above under "(c) Additional Substituents."

(ii) Hydrocarbon compound having cationic group In the present invention, the hydrocarbon compound having cationic group is a compound in which one or more hydrocarbon groups are bonded to one cationic group.The total carbon number of the hydrocarbon compound having cationic group is preferably 4 or more, more preferably 8 or more, even more preferably 12 or more, even more preferably 16 or more, and even more preferably 18 or more, from the viewpoint of easy removal of deposits from the membrane, and is preferably 40 or less, more preferably 30 or less, even more preferably 26 or less, and even more preferably 22 or less, from the viewpoint of handleability.

The hydrocarbon compound having a cationic group is a compound in which the hydrocarbon group is directly bonded to a nitrogen atom or a phosphorus atom via a covalent bond when the cationic group is a primary amine, secondary amine, tertiary amine, quaternary ammonium, phosphonium, etc.; when the cationic group is an amidine, guanidine, etc., the hydrocarbon compound is a compound in which the hydrocarbon group is bonded to at least one of the nitrogen atom or carbon atom of the functional group via a covalent bond; and when the cationic group is an imidazolium, pyridinium, imidazoline, etc., the hydrocarbon compound is a compound in which at least one hydrocarbon group is bonded to any position of the ring structure via a covalent bond.
The hydrocarbon compound having a cationic group is more preferably one that does not contain an oxyalkylene group.

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 hydrocarbon compound having a cationic 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.

The hydrocarbon compound having a cationic group may have a substituent. Specific examples of the substituent include those described above under "(c) Additional Substituents."

(Amount of modifying compound used)
In the step of obtaining modified cellulose fibers, the equivalent of the functional group capable of reacting with the anionic group of the modifying compound used relative to the anionic group in the anion-modified cellulose fibers is preferably 0.1 equivalents or more, more preferably 0.5 equivalents or more, even more preferably 1 equivalent or more, and even more preferably 1.5 equivalents or more, from the viewpoint of improving the durability of the synovial fluid performance of the film. Also, from the viewpoint of film formability, it is preferably 20 equivalents or less, more preferably 10 equivalents or less, and even more preferably 2 equivalents or less.

(3) Micronization process: Micronization of cellulose at any stage of the modified cellulose fiber production process can reduce the micrometer-scale cellulose to the nanometer-scale. Reducing the average fiber diameter to nanometer size improves the strength of the film when it is formed, so it is preferable to further carry out a micronization process.

A known disperser is preferably used for the micronization process. For example, a disintegrator, beater, 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. Furthermore, the solids content of the reaction product fiber in the micronization process is preferably 50% by mass or less.

[Component (B)]
Component (B) in the present invention is water. Component (B) serves as a solvent when preparing component (A) and as one of the constituent components of the emulsion composition in the present invention.

[Component (C)]
Component (C) in the present invention is an organic compound that is non-volatile at 25°C and 1 atmosphere. Component (C) may be a solvent used in preparing component (A). In this specification, an organic compound that is non-volatile at 25°C and 1 atmosphere means an organic compound that has a vapor pressure of less than 10 Pa under such conditions.

The solubility of component (C) in water is preferably 10 g or less, more preferably 1 g or less, per 100 g of water at 25°C.
The molecular weight of component (C) is preferably 100,000 or less, more preferably 50,000 or less, and even more preferably 10,000 or less, from the viewpoint of facilitating removal of deposits from the membrane, and from the same viewpoint, it is preferably 100 or more, and more preferably 200 or more.

Specific examples of component (C) in the present invention include oils, organic solvents, polymerizable monomers, prepolymers, etc. Component (C) in the present invention is preferably an oil. From the viewpoint of easily removing deposits from the film, examples of the oil include one or more selected from the group consisting of alcohols, ester oils, hydrocarbon oils, silicone oils, ether oils, oils, fluorine-based inert liquids, and fatty acids. One or more selected from the group consisting of ester oils, silicone oils, ether oils, oils, and fluorine-based inert liquids are preferred, one or more selected from the group consisting of silicone oils, ester oils, and ether oils are more preferred, and silicone oils and/or ester oils 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 easily removing deposits from the film, component (C) preferably has an SP value of 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. For example, oils with an SP value of 10 or less, as described below, are preferred.

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 are suitable for use in the present invention include oleic acid (SP value: 9.2), 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), and fluorine-based inert liquids. (For example, 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 oil (for example, KF96-1cs (manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7.3) , KF-96-10cs (manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96-50cs (manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96-100cs (manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96-1000cs (manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7.3), KF-96H-10,000cs (manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7.3), etc.

[Component (D)]
The emulsion composition of the present invention may further contain an organic compound that is volatile at 25°C and 1 atmosphere. By incorporating such a component into the emulsion composition, it is possible to easily form a film on a 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.

[Component (E)]
The emulsion composition of the present invention may further contain a polyether-modified silicone compound as component (E). By incorporating such component (E) into the emulsion composition, the durability of the film can be improved, which is preferable.
An example of component (E) 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. -R ¹ (C ₂ H ₄ O) _p (C ₃ H ₆ O) _q In the group represented by R ² , (C ₂ H ₄ O) _p and (C ₃ H ₆ O) _q may be random or block.

From the viewpoint of the durability of the film obtained by drying the emulsion composition, the HLB value of component (E) is preferably within a specific range; specifically, it is preferably 1 or more, more preferably 5 or more, and even more preferably 10 or more, 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 of the HLB values of the components (E) 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 formula:
HLB value = 20 x sum of molecular weights of hydrophilic groups / molecular weight

The kinematic viscosity of component (E) at 25°C is preferably within a specific range from the viewpoint of the durability of the film obtained by drying the emulsion composition, 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 that can be preferably used as component (E) are commercially available. 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 the durability of the film obtained by drying the emulsion composition, KF-640, KF-642, KF-643, KF-351A, KF-354L, and KF-355A are preferably used. 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 component (E).

[Component (F)]
The emulsion composition of the present invention may further contain a polymer compound as component (F). Component (F) does not include components (A), (C), (D), or (E). Adding component (F) to the emulsion composition is preferred because it can improve the durability of the film.

The weight average molecular weight of component (F) 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.
As the component (F), one or more compounds selected from the group consisting of the following polymer compounds (X) and (Y) are preferred.
Polymer compound (X): A polymer compound having an ester group, an amide group, a urethane group, an amino group, an ether group, or a carbonate group in the main chain. Polymer compound (Y): A methacrylic or acrylic polymer having an ester group or an amide group in the side chain.

Specific preferred examples of component (F) include polyalkyl(meth)acrylates such as polymethyl(meth)acrylate, polyethyl(meth)acrylate, and polybutyl(meth)acrylate; copolymers with acrylics such as styrene-acrylics and urethane-acrylics; 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.

[Other ingredients]
In addition to the above components, the emulsion composition of the present invention may contain, within the scope of the present invention, plasticizers, crystal nucleating agents, fillers (inorganic fillers, organic fillers), hydrolysis inhibitors, flame retardants, antioxidants, lubricants such as hydrocarbon waxes and anionic surfactants, UV absorbers, antistatic agents, antifogging agents, light stabilizers, pigments, mildew inhibitors, antibacterial agents, foaming agents, surfactants; polysaccharides such as starches and alginic acid; natural proteins such as gelatin, glue, and casein; inorganic compounds such as tannin, zeolite, ceramics, and metal powder; fragrances; flow adjusters; leveling agents; conductive agents; UV dispersants; and deodorizers, within the scope of the present invention. Similarly, other polymeric materials and other compositions may also be added within the scope of the present invention.

2. Substrate The substrate is a material that ensures the mechanical strength of various members, and examples thereof include various metals such as steel, stainless steel, copper alloys, and aluminum, as well as plastics, glass, and concrete.

From the viewpoint of mechanical strength, the thickness of the substrate is preferably 0.01 mm or more, more preferably 0.1 mm or more, and even more preferably 1 mm or more; from the viewpoint of productivity, it is preferably 100 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less.

3. Method for Forming a Laminate The method for forming a laminate of the present invention includes the following steps 1 and 2.
Step 1: A step of applying an emulsion composition containing the following components (A) to (C) onto a resin surface: (A) cellulose fibers having a modified group; (B) water; and (C) an organic compound that is nonvolatile at 25°C and 1 atmosphere. Step 2: A step of drying the emulsion composition after Step 1.

<Step 1>
Step 1 is a step of applying an emulsion composition onto a resin surface.
Examples of application methods include spraying the emulsion composition using an air spray, airless spray, trigger spray, or the like, spraying using an aerosol can, application using a brush, roller, cloth, or the like, dip application, etc. These application methods can be said to be very simple and convenient.
The thickness of the coating film on the resin surface is preferably 0.001 mm or more, more preferably 0.01 mm or more, and even more preferably 0.1 mm or more, from the viewpoint of easy removal of deposits from the film, and is preferably 10 mm or less, more preferably 1 mm or less, and even more preferably 0.5 mm or less, from the viewpoint of productivity.

<Step 2>
Step 2 is a step of drying the emulsion composition after step 1. By drying the emulsion composition, a film is formed on the resin surface.

The emulsion composition may be dried by air drying at room temperature and normal pressure, or the drying may be accelerated by heating or reducing the pressure.

<Emulsifying composition>
The emulsion composition contains the above-mentioned components (A), (B), and (C). If necessary, it may also contain components (D), (E), and/or (F).

From the viewpoint of emulsifying power, the content of component (A) in the emulsion composition 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 handleability, on the other hand, it is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

From the viewpoint of maintaining the emulsified state, the content of component (B) in the emulsion composition is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and even more preferably 70% by mass or more. On the other hand, from the viewpoints of viscosity and handleability, it is preferably 98% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less.

From the viewpoint of maintaining the emulsified state, the content of component (C) in the emulsion composition is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more; from the same viewpoint, it is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 7% by mass or less.

From the viewpoint of facilitating film formation on a substrate, the content of component (D) in the emulsion composition is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more; from the same viewpoint, it is preferably 50% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

From the viewpoint of improving the durability of the film, the content of component (E) in the emulsion composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more; from the same viewpoint, it is preferably 10% by mass or less, more preferably 1% by mass or less, and even more preferably 0.3% by mass or less.

From the viewpoint of improving the durability of the film, the content of component (F) in the emulsion composition is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more; from the same viewpoint, it is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 7% by mass or less.

The mass ratio of component (C) to component (A) in the emulsion composition ((C)/(A)) is preferably 0.1 or more, more preferably 1 or more, and even more preferably 1.5 or more, from the viewpoint of easily removing deposits from the film; and from the same viewpoint, it is preferably 10 or less, more preferably 5 or less, and even more preferably 2 or less.

From the viewpoint of ease of handling, the viscosity of the emulsion composition at 25°C is preferably 0.5 mPa·s or more, more preferably 0.8 mPa·s or more, even more preferably 1 mPa·s or more, and even more preferably 5 mPa·s or more; from the same viewpoint, it is preferably 30 Pa·s or less, more preferably 10 Pa·s or less, even more preferably 1 Pa·s or less, even more preferably 100 mPa·s or less, and even more preferably 20 mPa·s or less. Viscosity can be measured according to the method described in the Examples below.

The median particle size of the emulsified droplets in the emulsion composition, as measured by the laser diffraction method 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 water resistance, synovial fluid resistance, and durability thereof; and 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.

<Method for preparing emulsion composition>
The method for preparing the emulsion composition of the present invention includes a step of mixing the aforementioned components (A), (B), and (C), or a step of mixing anion-modified cellulose fiber, a modifying compound, components (B), and (C), etc.

By mixing the components, emulsification occurs, resulting in an emulsion composition. 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 be performed by combining two or more operations.

The temperature and time for mixing the components are preferably in the range of 5 to 50°C, and preferably in the range of 1 minute to 3 hours.

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

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 anion-modified cellulose fibers and 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 Anion-Modified Cellulose Fibers and 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) = (carboxy group content of oxidized cellulose fiber after oxidation treatment) - (carboxy 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 modified cellulose fibers]
The crystalline structure of the 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 type I 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.)

[Measurement of Viscosity of Emulsion Composition]
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.

[Measurement of particle size of emulsion droplets by laser diffraction method]
The particle size of the emulsified droplets is measured by laser diffraction using LA-960 manufactured by Horiba Ltd.
Measurement conditions: Water is added to a measurement cell, and the volume particle size distribution and median (volume cumulative median particle size (D50)) 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.

[Measurement of film thickness]
The thickness of the dried film is 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 portion of the film was scraped off with a metal spatula, and the sample with the exposed lower layer was measured. The height of the lower layer and the height of the film were measured using the built-in image processing software, and the thickness of the film was determined by taking the difference between them.

[Anion-modified cellulose fiber]
Anion-modified cellulose fibers having the physical properties shown in Table 1 were used as raw materials.

Such anionically modified cellulose fibers can be prepared, for example, by the TEMPO oxidation treatment described below.

[TEMPO oxidation treatment]
10 g of bleached coniferous kraft pulp fiber (as the raw natural cellulose fiber) and 990 g of deionized water were weighed into a 2 L PP beaker equipped with a mechanical stirrer and stirring blades and stirred at 25°C and 100 rpm for 30 minutes. Next, 0.13 g of TEMPO, 1.3 g of sodium bromide, and 35.5 g of a 10.5 wt% aqueous solution of sodium hypochlorite were added to the 10 g of pulp fiber in this order. Next, pH stat titration was performed using an automatic titrator, and 0.5 M aqueous sodium hydroxide solution was added dropwise to maintain the pH at 10.5. The reaction was carried out at 25°C for 120 minutes with a stirring speed of 100 rpm.

Next, 0.01 M hydrochloric acid is added to the suspension while stirring to adjust the pH of the suspension to 2. The solids are then filtered off by suction filtration. The process of dispersing the solids in deionized water and filtering off the solids by suction filtration is repeated until the conductivity of the filtrate reaches 200 μs/cm or less. The resulting solids are then dehydrated to obtain anion-modified cellulose fibers.

[Preparation of reduction-treated, finely divided anion-modified cellulose fibers]
The anion-modified cellulose fibers were subjected to a micronization treatment and then a reduction treatment to prepare micronized anion-modified cellulose fibers having the physical properties shown in Table 2.

Such finely divided anionically modified cellulose fibers can be prepared, for example, by the following fine division and reduction treatments.

[Fine processing]
Deionized water was added to the anion-modified cellulose fibers to prepare 100 g of a suspension (solid content 2.0% by mass), to which 0.5 M aqueous sodium hydroxide solution was added to adjust the pH to 8. Deionized water was then 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 to obtain a micronized anion-modified cellulose fiber dispersion (solid content 1.0% by mass).

[Reduction process]
182 g of a finely divided anion-modified cellulose fiber dispersion (solid content 1.0% by mass) was weighed out and added with deionized water to a total of 400 g. 1.2 mL of 0.1 M aqueous sodium hydroxide and 120 mg of sodium borohydride were added thereto and stirred at 25°C for 4 hours. 9 mL of 1 M hydrochloric acid was then added and stirring was continued. After stirring was completed, the solids obtained by suction filtration were dispersed in deionized water and the solids were separated by suction filtration. This operation was repeated six times. In this way, a finely divided anion-modified cellulose fiber dispersion (solid content 0.9% by mass) in which the aldehyde groups present in the finely divided anion-modified cellulose fibers had been reduced was obtained.

[Preparation of emulsified mixture]
In a beaker, 66.7 g of the dispersion of the micronized anion-modified cellulose fiber (solids content 0.9% by mass) having the physical properties listed in Table 2, 6.0 g of silicone oil, and 2.67 g of amino-modified silicone as a modifying compound (corresponding to 1.75 equivalents relative to the carboxy groups of the anion-modified cellulose fiber) were mixed, and deionized water was added to make a total of 100 g. This dispersion was stirred with a mechanical stirrer at room temperature 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 an emulsified mixture containing modified cellulose fiber in which the amino-modified silicone was bonded to the anion-modified cellulose fiber via ionic bonds. The resulting mixture was a cloudy white liquid, and oil droplets dispersed in water were observed under an optical microscope, indicating that it was an emulsion. The median particle size of the emulsified droplets was 300 nm.

Examples 1 and 2
The emulsified mixture and the raw materials shown in the table were weighed into a beaker so as to achieve the active ingredient concentrations shown in the table, and the mixture was stirred at 25° C. for 30 minutes to obtain an emulsified composition for forming a laminate.

Details of representative components used in the examples are summarized below.
[Modification compound]
Amino-modified silicone: DOWSIL ^™ SS-3551, manufactured by Dow Toray Industries, Inc., kinematic viscosity: 1,000, amino equivalent: 1,700
[Component (C)]
Silicone oil: KF-96-100cs, manufactured by Shin-Etsu Chemical Co., Ltd., SP value: 7.3
[Component (D)]
N-methylpyrrolidone: Fujifilm Wako Pure Chemical Industries, Ltd. 2-propanol: Fujifilm Wako Pure Chemical Industries, Ltd.
[Component (E)]
Polyether-modified silicone: Shin-Etsu Chemical Co., Ltd., KF-642, HLB: 14
[Component (F)]
Styrene acrylic: NeoCryl XK-188 (solid content 44.5% by mass), manufactured by DSM

[Coating of lower layer body]
An acrylic resin-based paint (SEAFLO NEO CF Z, manufactured by Chugoku Paint Co., Ltd.) was applied to a SUS329J4L substrate (100 mm x 300 mm x 3 mm thick) to form a lower layer using an applicator (manufactured by Tester Sangyo Co., Ltd.) to a thickness of 200 μm. The solvent was evaporated by drying at room temperature for 12 hours, resulting in a laminated structure of the substrate and lower layer with a film thickness of approximately 100 μm. Note that the acrylic resin contained in the acrylic resin-based paint used here corresponds to a soluble resin.

[Creating an upper layer on a lower layer]
Each of the emulsion compositions prepared in Examples 1 and 2 was spread over the entire surface of the lower layer of the laminated structure to a coating thickness shown in the table. The solvent was then evaporated by drying at room temperature for 24 hours, yielding a structure comprising a laminate of the lower layer and the upper layer.

Comparative Example 1
A structure having only the lower layer body without the upper layer body was used as Comparative Example 1.

[Evaluation of synovial fluid]
Test Example 1
The structures of Examples 1 and 2 and Comparative Example 1 prepared as described above were placed horizontally with the upper layer facing upward. 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 water droplet began to slide was measured. The smaller the water droplet sliding angle, the higher the synovial properties of the film. The composition of each component (mass parts in the dry film) and the evaluation results are shown in the table below. However, if the water droplet did not slide even when tilted to 85°, the water droplet sliding angle was recorded as "greater than 85".

[Field aquatic organism adhesion test]
Test Example 2
The substrates having the laminate of the upper and lower layers of Examples 1 and 2 and the substrate of Comparative Example 1 were connected with chains and placed in seawater near Shimotsu Port in Wakayama Prefecture so that they were 2 m deep from the water surface at low tide, and an immersion test in seawater was conducted for 7 months. After 1 month, 3 months, and 7 months of immersion, the degree of adhesion of crustaceans and algae to the substrates was visually evaluated. The evaluation criteria were as follows: The smaller the value, the greater the effect of inhibiting adhesion of aquatic organisms.

1: The adhesion of aquatic organisms is 2% or less of the area of the substrate surface.
2: Aquatic organisms are attached to more than 2% by area and less than 10% by area of the substrate surface.
3: Aquatic organisms are attached to more than 10% by area and up to 20% by area of the substrate surface.
4: Aquatic organisms are attached to more than 20% by area but not more than 30% by area of the substrate surface.
5: Aquatic organisms are attached to more than 30% by area and up to 50% by area of the substrate surface.
6: Aquatic organisms are attached to more than 50% but not more than 80% of the area of the substrate surface.
7: A state in which aquatic organisms are attached to more than 80% of the area of the substrate surface.

[Deposit removal test]
Test Example 3
In the above Test Example 1, the removability of aquatic organisms attached to the substrate was evaluated after 1 month, 3 months, and 7 months according to the following criteria. The water flow here was evaluated by flowing water at a speed of 13.3 L/min in a direction horizontal to the substrate. The smaller the value, the easier it was to remove the attached organisms.
In Example 2, the upper layer peeled off from the lower layer after three months, and the evaluation was terminated at that point.

1: Only the deposits can be removed with a water stream.
2: The upper layer can be removed by using a water flow to peel off the attached material.
3: Only the adhesions can be removed by using a water jet and scrubbing.
4: Tools are required to remove the deposits.

Furthermore, the surface condition after removal of the deposits was visually inspected and evaluated for the presence or absence of surface damage due to the removal process. In cases where the removability score was 2 or 3 (the upper layer was also peeled off), the surface condition of the lower layer after the upper layer was peeled off was evaluated.

From Table 1, it can be seen that the structure of the example in which the upper layer body is laminated on the lower layer body has the effect of suppressing the adhesion of aquatic organisms itself compared to the lower layer body alone, and is also excellent in removing attached aquatic organisms. It was confirmed that it was particularly excellent in suppressing the adhesion of crustaceans.
Furthermore, it was found that the structure of the example in which the upper layer body was laminated on the lower layer body could be easily peeled off together with the attached matter using only a water flow after immersion for a certain period of time, and a clean lower layer body without any defects could be exposed. Therefore, it is possible to form an upper layer body again on the lower layer body with a simple operation using the emulsion composition of the present invention.

A comparison of Examples 1 and 2 revealed that the durability period until the upper layer peeled off from the lower layer was longer when N-methylpyrrolidone was used as component (D) than when 2-propanol was used. The reason for this is unclear, but it is thought that although they are organic media with similar SP values, N-methylpyrrolidone has a higher boiling point than 2-propanol and takes longer to volatilize, allowing it to slowly interdiffuse with the lower layer. On the other hand, when crustaceans adhered to Comparative Example 1, tools were required to remove the adhesions, and defects were found on the surface after removal.

1 Base material 2 Resin layer 3 Film

Claims (3)

A method for forming a laminate, comprising the following steps 1 and 2:
Step 1: A step of applying an emulsion composition containing the following components (A) to (D) onto the surface of a dissolvable resin: (A) cellulose fibers having a modifying group; (B) water; and (C) an organic compound that is nonvolatile at 25°C and 1 atmosphere , wherein the organic compound is one or more organic compounds selected from the group consisting of alcohols, ester oils, hydrocarbon oils, silicone oils, ether oils, oils and fats, fluorine-based inert liquids, and fatty acids.
(D) Organic compounds that are volatile at 25°C and 1 atmosphere
Step 2: After Step 1, drying the emulsion composition The method for forming a laminate according to claim 1 , wherein the emulsion composition further contains the following component (E):
(E) Polyether-modified silicone The method for forming a laminate according to claim 1 or 2 , wherein the emulsion composition further contains the following component (F):
(F) Polymer compounds (excluding those falling under component (A), component (C), component (D), or component (E))