KR20180084119A - A coating composition for forming a friction-reducing coating film, a coating film, and a coating film- - Google Patents

Abstract

The present invention relates to a paint for forming a frictional resistance reducing coating film, which comprises a hydrolyzable polymer (A) and a hydrophilic polymer (B) having a weight average molecular weight of 500,000 or more and has a pigment volume concentration (PVC) A coating composition for forming a frictional resistance reducing coating film capable of sufficiently maintaining the physical properties and the frictional resistance reducing effect of a coating film over a long period of time in water as a composition, a coating film for reducing frictional resistance obtained by curing the coating composition, And a method for producing the same.

Description

A coating composition for forming a friction-reducing coating film, a coating film, and a coating film-

The present invention relates to a coating composition for forming a coating film for reducing frictional resistance, a coating film for reducing frictional resistance formed by using the coating composition, and a coating film base material having the coating film on a substrate.

When friction occurs between the surface of the structure and the liquid, such as when a structure such as a ship propels water, or when a liquid is transported through a pipe structure such as a pipeline, a large energy is consumed by frictional resistance. As a method for reducing the frictional resistance, for example, there is a method using a so-called Tombs effect in which the generation of turbulence near the surface of the structure is suppressed by adding a polymer compound or fiber to the liquid. As a method using the Tombs effect, for example, a technique of improving the renewability of the coating film by including a hydrolyzable polymer in the coating film and making it easy to release the polymer compound or the like from the coating film .

More specifically, in Patent Document 1, a resin (b) having film-renewal property such as a water-soluble polymer (a) such as polyethylene oxide and a resin containing a metal ester-containing acrylic resin or a triorganosilyl (meth) Based on the total weight of the coating composition. Further, in Patent Document 2, a self-burning type resin, a water-soluble polymer, a pigment, and a mixture of one or a plurality of mixtures selected from the group consisting of a zinc acrylate polymer, a copper acrylate polymer and a silyl acrylate polymer, A friction-reducing coating composition containing a solvent has been proposed.

Japanese Patent Application Laid-Open No. 2001-342432 International Publication No. 2011/34246

The coating films for reducing frictional resistance, including Patent Documents 1 and 2, have been extensively studied up to now, but a coating film showing sufficient performance for practical use has not been widely spread. The following are considered to be main factors. That is, when a coating film containing a hydrolyzable polymer as a binder and a hydrophilic polymer compound exhibiting a Toms effect is immersed in water, the absorption of water into the coating film is accelerated due to the hydrophilic property of the polymer compound, There is a problem in that the coating film can not maintain a sufficient strength in water due to a rapid hydrolysis reaction in the coating film and also the hydrolysis reaction proceeds rapidly on the surface of the coating film, There is a problem that the frictional resistance can not be reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a coating composition for forming a frictional resistance reducing coating film which can sufficiently retain the physical properties and the frictional resistance reducing effect of a coating film over a long period of time in water.

The present invention also provides a coating film for reducing frictional resistance obtained by curing the coating composition, a coating film-attached substrate having the coating film on a substrate, and a process for producing the same.

The inventors of the present invention have conducted intensive studies and have found that a coating film formed by using a coating composition in which a hydrolyzable polymer and a hydrophilic polymer having a specific weight average molecular weight are used together and the pigment volume concentration (PVC) is adjusted to a specific range, It was found that sufficient strength was maintained throughout. Further, it has been found that the coating film unexpectedly remarkably improves the frictional resistance reducing effect as compared with the conventional coating film, and completed the present invention. The gist of the present invention is as follows.

The present invention relates to the following [1] to [12].

(1) A coating composition for forming a friction resistance reducing coating film, which comprises a hydrolyzable polymer (A) and a hydrophilic polymer (B) having a weight average molecular weight of 500,000 or more and has a pigment volume concentration (PVC) .

[2] The coating composition according to the above [1], wherein the content of the hydrolyzable polymer (A) in the coating material solids is 50 to 98% by mass.

[3] The coating composition according to the above [1] or [2], wherein the content of the hydrophilic polymer (B) in the solid content of the coating is 1 to 45 mass%.

[4] The coating composition according to any one of [1] to [3], wherein the hydrolyzable polymer (A) has a metal ester group.

[5] The coating composition according to [4], wherein the metal ester group is a divalent metal ester group represented by the following formula (I).

(Wherein M represents a metal and * represents an arbitrary organic group).

[6] The hydrophilic polymer (B) is a copolymer having a structural unit derived from one hydrophilic group-containing unsaturated monomer or a copolymer having a structural unit derived from at least two hydrophilic group-containing unsaturated monomers. The coating composition according to any one of [5] to [5].

[7] The coating composition according to [6], wherein the hydrophilic group-containing unsaturated monomer is at least one selected from a nonionic group-containing unsaturated monomer, an anionic group-containing unsaturated monomer and a cationic group-containing unsaturated monomer.

[8] The coating composition according to any one of [1] to [7], wherein the hydrophilic polymer (B) has a weight average molecular weight (Mw) of 3,000,000 or more.

[9] A friction resistance reducing coating film obtained by curing the coating composition according to any one of [1] to [8].

[10] A coated film-attached substrate having the friction-reducing coating film as described in [9] above on a substrate.

[11] The coated film-attached substrate according to [10], wherein the substrate is a ship.

[12] A process for producing a coating material or impregnated material by applying or impregnating a coating composition according to any one of [1] to [8] above to a substrate, (2) of curing the coating composition by a method comprising the steps of:

According to the present invention, it is possible to provide a coating composition for forming a frictional resistance reducing coating film capable of sufficiently maintaining the physical properties and the frictional resistance reducing effect of a coating film over a long period of time in water.

Further, the present invention can provide a coating film for reducing frictional resistance, a coating film-adhered base material having the coating film on the base material, and a method for producing the same, wherein the coating composition is cured.

[Coating Composition for Formation of Friction Resistant Reducing Film]

(A) and a hydrophilic polymer (B) having a weight average molecular weight of 500,000 or more, wherein the pigment volume concentration (PVC) in the solid content of the paint is less than 20% by volume Is a coating composition for forming a frictional resistance reducing coating film.

≪ Hydrolyzable polymer (A) >

The coating composition for forming a frictional resistance reducing coating film of the present invention comprises a hydrolyzable polymer (A). When the hydrolyzable polymer (A) is used in the present invention, since the hydrolyzable polymer (A) present on the surface of the coating film in water is gradually hydrolyzed and the surface of the film is sequentially updated, the hydrophilic polymer (B) Thereby exhibiting an effect of reducing the friction resistance.

The hydrolyzable polymer (A) in the present invention has a hydrolyzable group, and preferably has a structural unit derived from the hydrolyzable group-containing monomer (a0) in the hydrolyzable polymer (A). The "hydrolyzable group" in the present invention refers to a metal ester group or a silyl ester group, and the "metal ester group" refers to a group formed by a bond between a metal and a carboxylic acid. The "polyvalent metal ester group" or the "divalent metal ester group" to be described later refers to a group formed by bonding of a polyvalent metal or a divalent metal and a carboxylic acid.

The hydrolyzable group of the hydrolysable polymer (A) in the present invention is preferably a metal ester group, more preferably a polyvalent metal ester group, from the viewpoint of exhibiting a frictional resistance reducing effect over a long period of time, The divalent metal ester group to be displayed is more preferable.

(Wherein M represents a metal and * represents an arbitrary organic group).

Examples of M in the formula (I) include magnesium, calcium, neodymium, titanium, zirconium, iron, ruthenium, cobalt, nickel, copper, zinc and aluminum. Among them, metals belonging to groups 10 to 12 of the periodic table such as nickel, copper and zinc are preferable, and copper and zinc are more preferable, and zinc is more preferable.

The hydrolyzable polymer (A) having a metal ester group can be produced, for example, in the following procedure.

First, a mixed solution obtained by mixing a solvent and a metal component such as zinc oxide is stirred while being heated to about 50 to 80 캜, and a mixed solution of organic acid such as methacrylic acid or acrylic acid and water is dropped thereon, To prepare a decomposable group-containing monomer (a0).

Next, a solvent is placed in a freshly prepared reaction vessel, and the mixture is heated to about 80 to 120 DEG C, to which a monomer other than the hydrolyzable group-containing monomer (a0), a monomer having a hydrolyzable group (a0) And a solvent are added dropwise, and a polymerization reaction is carried out to obtain a hydrolyzable polymer (A) having a metal ester group.

On the other hand, the ratio of the respective content (mass) of the structural units derived from each monomer in the hydrolyzable polymer (A) can be regarded as being the same as the ratio of the input amounts (mass) of the respective monomers used in the polymerization reaction.

Examples of the monomer other than the hydrolyzable group-containing monomer (a0) include monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl Acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (Meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isooctyl (meth) acrylate, Alkyl (meth) acrylates such as aryl (meth) acrylate, phenyl (meth) acrylate and benzyl (meth) acrylate; aryl (meth) acrylates or aralkyl (meth) acrylates;

(Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, methoxypropyl (Meth) acrylates such as acrylate, 2-butoxyethyl (meth) acrylate, isobutoxy butyraldehyde glycol (meth) acrylate and 2-phenoxyethyl (meth) acrylate, Alkyl (meth) acrylates;

(Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl Hydroxyalkyl (meth) acrylates such as cyipropyl (meth) acrylate;

And (meth) acrylates containing an organosiloxane group. These monomers may be used singly or in combination of two or more kinds.

Among the monomers other than the above-mentioned hydrolyzable group-containing monomer (a0), alkyl (meth) acrylate and alkoxyalkyl (meth) acrylate are preferable and methyl methacrylate, ethyl acrylate, butyl acrylate, 2- Ethyl acrylate, and 2-methoxyethyl methacrylate are more preferable.

The hydrolyzable polymer (A) of the present invention may be a homopolymer having a structural unit derived from one kind of hydrolyzable group-containing monomer (a0), or a structural unit derived from two or more kinds of the hydrolyzable group-containing monomer (a0) , A copolymer having a structural unit derived from at least one kind of the hydrolyzable group-containing monomer (a0) and a structural unit derived from a monomer other than the at least one kind of the hydrolyzable group-containing monomer (a0).

In the present invention, "(meth) acrylate" means "acrylate or methacrylate". Other similar notations mean the same.

The polymerization initiator that can be used in the production of the hydrolyzable polymer (A) is not particularly limited, and various radical polymerization initiators can be used. Specific examples include benzoyl peroxide, hydrogen peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, potassium persulfate, sodium persulfate, 2,2'-azobis (isobutyronitrile) [AIBN] Azobis (2-methylbutyronitrile) [AMBN], 2,2'-azobis (2,4-dimethylvaleronitrile) [ADVN] and tert-butyl peroctoate [TBPO] And the like. These polymerization initiators may be used alone or in combination of two or more. On the other hand, these radical polymerization initiators may be added to the reaction system only at the initiation of the reaction, or may be added both to the reaction system at the initiation of the reaction and during the reaction.

The amount of the polymerization initiator used in the production of the hydrolyzable polymer (A) is preferably 5 to 20 parts by mass per 100 parts by mass of the total amount of the respective monomers.

The chain transfer agent usable in the production of the hydrolyzable polymer (A) is not particularly limited, and examples thereof include? -Methylstyrene dimer, thioglycolic acid, dietherphen, terpinolene,? -Terpinene; mercaptans such as tert-dodecyl mercaptan and n-dodecyl mercaptan; Halides such as carbon tetrachloride, methylene chloride, bromoform and bromotrichloroethane; Secondary alcohols such as isopropanol and glycerin; And the like. These chain transfer agents may be used alone or in combination of two or more.

When a chain transfer agent is used in the production of the hydrolyzable polymer (A), the amount of the chain transfer agent to be used is preferably 0.1 to 5 parts by mass per 100 parts by mass of the total amount of the respective monomers.

Examples of the solvent which can be used for the production of the hydrolysable polymer (A) include propylene glycol monomethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol Polyhydric alcohol monoalkyl ethers such as monomethyl ether and tripropylene glycol monobutyl ether; Aromatic hydrocarbon solvents such as toluene, xylene and mesitylene; Water and the like.

In the case of using a solvent in the production of the hydrolyzable polymer (A), there is no particular limitation on the amount to be used, but it is preferably 5 to 150 parts by mass per 100 parts by mass of the total amount of the respective monomers.

The weight average molecular weight (Mw) of the hydrolyzable polymer (A) is preferably 1,000 to 200,000, more preferably 2,000 to 70,000, and still more preferably 3,000 to 40,000. When the weight average molecular weight (Mw) of the hydrolyzable polymer (A) is within the above range, the spray coating workability of the coating composition is improved and the physical properties of the coating film are further improved.

On the other hand, the weight average molecular weight (Mw) of the hydrolysable polymer (A) indicates the value of gel permeation chromatography (GPC) measured by the method described in the examples.

The content of the hydrolysable polymer (A) in the solid content of the coating composition is preferably 50% by mass or more, more preferably 55% by mass or more, still more preferably 60% by mass or more, still more preferably 65% , More preferably not less than 70 mass%, and preferably not more than 98 mass%, more preferably not more than 95 mass%, more preferably not more than 90 mass%, still more preferably not more than 85 mass% And even more preferably 80 mass% or less. When the content of the hydrolyzable polymer (A) is within the above range, excellent frictional resistance reduction effect can be obtained over a long period of time, and the strength of the coating film can be maintained over a long period of time.

The term " solid content of the coating composition " in the present invention means a component other than the organic solvent (D) to be described later and the volatile component contained as a solvent in each component, and the " content in the solid content of the coating composition & It is regarded as the content in the solid content obtained by drying in a hot-air dryer at 125 캜 for 1 hour. In the present specification, the term "solid content of the coating composition" is abbreviated as "solid content of the coating".

≪ Hydrophilic polymer (B) >

The coating composition of the present invention contains a hydrophilic polymer (B) having a weight average molecular weight (Mw) of 500,000 or more for the purpose of reducing the frictional resistance of a coating film formed by the coating composition.

When the hydrophilic polymer (B) is used in the coating composition of the present invention, the development of turbulent eddies near the coating film is inhibited by migration of the hydrophilic polymer (B) from the inside of the coating film to the surface of the coating film, Can be reduced.

On the other hand, the "hydrophilic polymer" in the present invention means a polymer having a hydrophilic group in its molecule such as a hydroxyl group, an amino group, an amide group, an alkoxy group, an ether group (including an alkylene oxide unit), a carboxyl group, An ammonium salt group and the like.

The hydrophilic polymer (B) in the present invention is preferably at least one selected from the hydrophilic synthetic polymer (B1) and the hydrophilic natural product-derived polymer (B2).

[Hydrophilic synthetic polymer (B1)]

Examples of the hydrophilic synthetic polymer (B1) include hydrophilic group-containing vinyl polymers, polyalkylene oxides and polyester polymers. Of these, hydrophilic group-containing vinyl polymers and polyalkylene oxides are preferred. These hydrophilic synthetic polymers (B1) may be used alone or in combination of two or more.

(Hydrophilic group-containing vinyl-based polymer)

The vinyl-based polymer containing a hydrophilic group includes, for example, a polymer having a structural unit derived from a hydrophilic group-containing unsaturated monomer containing at least one hydrophilic group.

Examples of the hydrophilic group-containing unsaturated monomer include a nonionic group-containing unsaturated monomer, an anionic group-containing unsaturated monomer, and a cationic group-containing unsaturated monomer.

Examples of the nonionic group-containing unsaturated monomer include hydroxides such as (meth) acrylamide, hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate and methoxypolyethylene glycol mono (meth) (Meth) acrylate containing an amide group or an ether group.

In the present invention, "(meth) acrylamide" means "acrylamide or methacrylamide".

Examples of the anionic group-containing unsaturated monomer include unsaturated monomer containing a carboxyl group such as (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid and crotonic acid, styrene sulfonic acid, 3- (methacryloyloxy) And unsaturated monomers containing sulfonic acid groups such as acrylamide propanesulfonic acid.

These anionic group-containing unsaturated monomers may be partially or completely neutralized. On the other hand, the neutralization may be carried out as it is as a monomer, or it may be neutralized after being made into a polymer.

Examples of the base used for neutralization include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, and amine compounds such as ammonia, triethanolamine and trimethylamine.

Examples of the unsaturated monomer containing a cationic group include at least one selected from an amino group-containing unsaturated monomer and a quaternary ammonium group-containing unsaturated monomer.

Examples of the amino group-containing unsaturated monomer include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N- (Meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminoethyl ) Acrylamide, N, N-diethylaminopropyl (meth) acrylamide, 2-vinylpyridine, 4-vinylpyridine and an acid represented by H ⁺ X ^- .

In addition, a quaternary ammonium salt group-containing as the unsaturated monomer, X ^- a counter ion (meth) oxyethyl-trimethyl-ammonium acrylate having a (meth) acryloyl oxy propyl trimethyl ammonium, a (meth) acryloyl-aminoethyl Trimethylammonium, (meth) acryloylaminopropyltrimethylammonium, diallyldimethylammonium, 1-ethyl-4-vinylpyridinium and 1,2-dimethyl-5-vinylpyridinium.

X ^- represents an anion, a halogenide ion is preferable, and a chloride ion is more preferable.

The hydrophilic synthetic polymer (B1) in the present invention may be a homopolymer having a structural unit derived from one kind of hydrophilic group-containing unsaturated monomer, or may be a copolymer having a structural unit derived from two or more kinds of hydrophilic group-containing unsaturated monomers .

As the hydrophilic group-containing unsaturated monomer in the present invention, at least one selected from a nonionic group-containing unsaturated monomer, an anionic group-containing unsaturated monomer and a cationic group-containing unsaturated monomer is preferable, and a nonionic group-containing unsaturated monomer and an anionic group- More preferably at least one selected from monomers, and more preferably at least one selected from acrylamide and acrylic acid and salts thereof.

In the present invention, the term " at least one selected from a nonionic group-containing unsaturated monomer, an anionic group-containing unsaturated monomer and a cationic group-containing unsaturated monomer " At least one selected from the group consisting of a nonionic group-containing unsaturated monomer "and" at least one kind selected from a cationic group-containing unsaturated monomer ", and" at least one kind selected from a nonionic group- Mixture of at least one selected from anionic group-containing unsaturated monomers "or" mixture of at least one selected from at least one unsaturated monomer selected from a nonionic group-containing unsaturated monomer and a cationic group-containing unsaturated monomer ".

When the hydrophilic polymer (B) is a copolymer of a nonionic group-containing unsaturated monomer and an anionic group-containing unsaturated monomer, the mass ratio (nonionic / anionic) of the nonionic group-containing unsaturated monomer to the anionic group-containing unsaturated monomer is preferably 40/60 to 90/10, more preferably 50/50 to 80/20, and still more preferably 55/45 to 75/25. On the other hand, the mass ratio [nonionic / anionic] can be calculated from the charging ratio of each monomer when the copolymer is produced.

The hydrophilic synthetic polymer (B1) may be a copolymer of a hydrophilic group-containing unsaturated monomer and other monomers.

Examples of other monomers include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 4-tert- -Butyl-2-methylstyrene, and the like.

Examples of the (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (Meth) acrylate and n-octyl (meth) acrylate.

When the hydrophilic synthetic polymer (B1) contains constituent units derived from other monomers, the content thereof is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less .

(Polyalkylene oxide)

Examples of the polyalkylene oxide used as the hydrophilic synthetic polymer (B1) include polyethylene oxide (PEO) and polyethylene oxide-polypropylene oxide copolymer (PEO-PPO), and among these, polyethylene oxide-polypropylene oxide Copolymer and polyethylene oxide are preferable, and polyethylene oxide is more preferable.

As the hydrophilic synthetic polymer (B1), commercially available ones can be used. (PEO) (PEO) manufactured by Sumitomo Seika Co., Ltd., and Meihei Chemical Industry Co., Ltd. are commercially available as a commercially available product, for example, a polyacrylamide copolymer, a polyacrylamide copolymer, (PEO-PPO), and "Alcox EP-20" (PEO-PPO).

[Hydrophilic natural material-derived polymer (B2)]

The hydrophilic natural material-derived polymer (B2) in the present invention refers to a polymer derived from animal and plant matter, or a polymer obtained by chemically modifying these polymers.

Examples of the hydrophilic natural product-derived polymer (B2) include, for example, phenglyric acid, guar gum, tara gum, locust bean gum (carob idemg), starch, pullulan, cellulose, xylose, chitin, chitosan, (Κ, ι, λ type), agar, xanthan gum, welan gum, dianthan gum, gellan gum, succinoglucan, curdlan, hyaluronic acid, dextran, γ Hydroxyethyl cellulose such as hydroxyethyl cellulose (HEC) and hydroxypropyl cellulose (HPC), hydroxypropyl cellulose such as hydroxypropylmethylcellulose (HPMC), hydroxypropylmethylcellulose Hydroxyalkyl (alkyl) celluloses such as hydroxyethylcellulose (HPMC) and hydroxyethylmethylcellulose (HEMC), carboxymethylcellulose (CMC), cationized cellulose, hydrophobized cellulose, solubilized starch, carboxymethyl starch and alginic acid propylene glycol esters And the like. These hydrophilic natural-product-derived polymers (B2) may be used alone or in combination of two or more.

Among them, it is preferable to use at least one selected from the group consisting of guar gum, tara gum, locust bean gum, starch, alginic acid or its salt, xanthan gum, welan gum, dianthan gum, gellan gum, succinoglycan, (HPC), hydroxyethyl methyl cellulose (HEMC), hydroxypropylmethyl cellulose (HPMC) and carboxymethyl cellulose (CMC) are preferable, and examples thereof include guar gum, tara gum, locust bean gum, xanthan gum, welan gum, hydroxypropylcellulose (HPMC), hydroxyethylmethylcellulose (HEMC), hydroxypropylmethylcellulose (HPMC) and carboxymethylcellulose (CMC) are more preferable, and guar gum, xanthan gum , Diethanol gum, hydroxyethyl methyl cellulose (HEMC) and hydroxypropyl methyl cellulose (HPMC) are more preferred.

The hydrophilic polymer (B) may be either solid or liquid at 23 占 폚, but is preferably solid at 23 占 폚.

When the hydrophilic polymer (B) is solid at 23 占 폚, the average particle diameter thereof is preferably 0.01 占 퐉 or more, more preferably 0.01 占 퐉 or more, more preferably 0.01 占 퐉 or more, More preferably at least 1 μm, even more preferably at least 3 μm, even more preferably at least 5 μm, and preferably at most 200 μm, more preferably at most 100 μm, even more preferably at most 50 μm Or less. On the other hand, the average particle diameter of the hydrophilic polymer (B) refers to a 50% diameter (median diameter) and can be measured by the method described in the examples.

The average particle diameter of the hydrophilic polymer (B) used in the present invention preferably has an average particle diameter before addition to the coating composition and also in any of the coating compositions. That is, it is preferable that the hydrophilic polymer (B) has low solubility or does not have solubility in the hydrolyzable polymer (A) from the viewpoint of suppressing the improvement of the viscosity of the coating composition.

The weight average molecular weight (Mw) of the hydrophilic polymer (B) is preferably 500,000 or more, preferably 1,000,000 or more, more preferably 1,500,000 or more, more preferably 1,800,000 or more, More preferably at least 2,000,000, even more preferably at least 2,500,000, even more preferably at least 3,000,000, even more preferably at least 3,500,000, even more preferably at least 4,000,000, even more preferably at least 4,500,000, Preferably not more than 100,000,000, more preferably not more than 20,000,000, more preferably not more than 15,000,000, still more preferably not more than 12,000,000 from the viewpoint of reducing the load on the substrate.

On the other hand, the "weight average molecular weight", the "number average molecular weight" and the "Z average molecular weight" of the hydrophilic polymer (B) are measured by gel permeation chromatography (GPC).

The ratio [Mw / Mn] of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the hydrophilic polymer (B) is preferably 1 to 10, and the number average molecular weight (Mn) of the hydrophilic polymer More preferably at least 300,000, more preferably at least 1,000,000, even more preferably at least 2,000,000, even more preferably at least 3,000,000 from the viewpoint of reducing the frictional resistance, and preferably at least 100,000, Is not more than 100,000,000, more preferably not more than 50,000,000, more preferably not more than 20,000,000, even more preferably not more than 10,000,000, still more preferably not more than 8,000,000.

The ratio [Mz / Mw] of the hydrophilic polymer (B) to the weight average molecular weight (Mw) to the Z average molecular weight (Mz) is preferably from 1 to 10, and the Z average molecular weight (Mz) of the hydrophilic polymer More preferably 1,000,000 or more, more preferably 2,000,000 or more, and preferably 1,000,000,000 or less, more preferably 500,000,000 or less, still more preferably 250,000,000 or more, in view of reducing friction resistance, Still more preferably not more than 100,000,000, still more preferably not more than 50,000,000, still more preferably not more than 25,000,000.

The viscosity average molecular weight (Mv) of the hydrophilic polymer (B) is preferably 100,000 or more, more preferably 1,000,000 or more, and preferably 100,000,000 or less, from the viewpoint of reducing the frictional resistance.

On the other hand, "viscosity average molecular weight (Mv)" refers to a value measured in accordance with JIS-K-7367 using the viscosity method prescribed in JIS-K-2283 or JIS-Z-8803.

On the other hand, the hydrophilic polymer (B) used in the present invention may form a complex in a coating film in water or in water, and may exhibit an effect of reducing the frictional resistance even if the average molecular weight is not in the above range In the present invention, however, the molecular weight of the aggregate may be within the range of the above average molecular weights.

The content of the hydrophilic polymer (B) in the coating composition is preferably 0.3% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 70% Preferably not more than 40 mass%, more preferably not more than 30 mass%, still more preferably not more than 25 mass%, still more preferably not more than 20 mass%, still more preferably not more than 15 mass% Is not more than 10% by mass.

The content of the hydrophilic polymer (B) in the solid content of the coating composition is preferably 1% by mass or more, more preferably 2% by mass or more, and still more preferably 2% by mass or more, from the viewpoint of reducing the frictional resistance and improving the coating film strength. , More preferably not less than 5 mass%, even more preferably not less than 6.5 mass%, and preferably not more than 45 mass%, more preferably not more than 30 mass%, further preferably not more than 25 mass% By mass or less, and more preferably 15% by mass or less.

≪ Pigment (C) >

In the present invention, the pigment (C) may be used for the purpose of coloring the coating film and concealing the foundation (undercoat), adjusting the coating film strength to a suitable value, and imparting antifouling properties.

Examples of the pigment (C) include talc, mica, clay, feldspar, zinc oxide, calcium carbonate, kaolin, alumina white, white carbon, aluminum hydroxide, magnesium carbonate, barium carbonate, barium sulfate, calcium sulfate and zinc sulfide And pigments such as pigments such as red pigments such as red pigments, red pigments such as red iron oxide, red gold copper, copper pyrithione and zinc pigments such as red iron oxide, red iron oxide, iron oxide black, carbon black, naphthol red and phthalocyanine blue, And an antifouling pigment such as pyrithione. Among them, it is preferable to include an extender pigment and an antifouling pigment, and more preferably include talc, zinc oxide, copper pyrithione and zinc pyrithione. These pigments may be used singly or in combination of two or more kinds.

≪ Pigment Volume Concentration (PVC) in Pigment Solids >

The pigment volume concentration (PVC) in the paint solid content in the paint composition of the present invention is less than 20% by volume, and from the viewpoints of improving the physical properties of the coating film and the frictional resistance reducing effect over the long term, , More preferably not more than 12 vol%, even more preferably not more than 10 vol%, even more preferably not more than 8 vol%, even more preferably not more than 7 vol%, more preferably 0 to 6 vol% desirable. If the PVC is within the above range, the ratio of the discontinuous phase of the pigment in the coating film increases and the proportion of the resin or the like forming the continuous phase increases, so that the penetration of water into the coating film is suppressed, The volume change due to the swelling of the hydrophilic polymer or the hydrolysis of the hydrolyzable polymer (A) is suppressed, and as a result, the film state is improved. In addition, since the rapid loss of the hydrophilic polymer (B) outside the coating film is suppressed, the frictional resistance reducing effect can be maintained over a long period of time. When the coating composition of the present invention does not contain the pigment (C), the amount of PVC in the solid content of the paint becomes 0% by volume.

On the other hand, PVC of the coating composition or coating film refers to a value measured by the following method.

10 g of the coating composition measured in the precipitation tube is stirred well with about 50 ml of the organic solvent contained in the coating composition, and then separated by centrifugal separation at 3500 rpm for 30 minutes, and the symbol is taken out. After repeating this operation three times, the residue in the precipitation tube was dried at 125 DEG C for 1 hour by using a hot air drier, and then the mass was measured. Based on the mass value and the specific gravity measured using the true specific gravity meter, . Next, the volume V2 of the solid content of the paint in 10 g of the paint composition is measured, and PVC = V1 / V2 is calculated using the values of V1 and V2.

When the coating composition does not contain an organic solvent or when the coating film after drying is to be evaluated, the above measurement is carried out using a mixed solvent of xylene / n-butanol = 7: 3 (mass ratio).

When the coating composition of the present invention contains the pigment (C), the amount thereof is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less based on the solid content of the coating composition . The lower limit of the content of the pigment (C) in the case where the coating composition of the present invention contains the pigment (C) is not particularly limited, but it is preferably 0.01% by mass or more in the solid content of the coating composition.

<Optional ingredients>

The coating composition for forming a frictional resistance reducing coating film of the present invention may contain an organic solvent (D), an organic antifouling agent (E), an antifogging agent (B) (G), a plasticizer (H) and a dehydrating agent (I) may be contained in addition to the monocarboxylic acid compound (F).

[Organic solvent (D)]

In the present invention, the organic solvent (D) may be used for the purpose of keeping the viscosity of the coating composition low and improving spray atomization.

As the organic solvent (D), an aromatic hydrocarbon-based, aliphatic hydrocarbon-based, alicyclic hydrocarbon-based, ketone-based, ester-based or alcohol-based organic solvent can be used, preferably an aromatic hydrocarbon-based organic solvent.

Examples of the aromatic hydrocarbon-based organic solvent include toluene, xylene, styrene, and mesitylene.

Examples of the aliphatic hydrocarbon-based organic solvent include pentane, hexane, heptane and octane.

Examples of the alicyclic hydrocarbon-based organic solvent include cyclohexane, methylcyclohexane and ethylcyclohexane.

Examples of ketone-based organic solvents include acetylacetone, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethyl carbonate and the like.

Examples of the ester organic solvent include propylene glycol monomethyl ether acetate and the like.

Examples of the alcohol-based organic solvent include isopropanol, n-butanol and propylene glycol monomethyl ether.

These organic solvents (D) may be used alone or in combination of two or more.

When the coating composition of the present invention contains the organic solvent (D), the content of the organic solvent (D) in the coating composition is preferably determined depending on the desired viscosity depending on the application form of the coating composition, etc., but usually 0.001 to 50 mass % Is preferable. When the content of the organic solvent (D) is excessively large, problems such as deterioration of sag prevention may occur.

[Organic Antifouling Agent (E)]

In the present invention, an organic antifouling agent (E) may be used for the purpose of improving the resistance to endogenous bio-fouling of a coating film.

Examples of the organic antifouling agent (E) include 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H- pyrrole-3-carbonitrile (abbreviation: trallopyryl) Dichloro-2-n-octyl-4-isothiazolin-3-one (abbreviation: DCOIT), a borane-nitrogen based base adduct (pyridine triphenylborane, 4-isopropylpyridine Diphenylmethylborane and the like), (+/-) - 4- [1- (2,3-dimethylphenyl) ethyl] -1H- imidazole (abbreviation: medetomidine), N, (2,4,6-trichlorophenyl) maleimide, 2-methylthio-4-tert-butylamino-6-cyclopropylamino- 3,5-triazine, 2,4,5,6-tetrachloroisophthalonitrile, bisdimethyldithiocarbamoyl zinc ethylenebisdithiocyanate, chloromethyl-n-octyldisulfide, N , N-dimethyl-N'-phenyl- (N'-fluorodichloromethylthio) sulfamide, tetraalkylthiuramide (2 ', 6 ' -diethylphenyl) maleimide and 2,3-dichloro-benzene diisocyanate, And N- (2'-ethyl-6'-methylphenyl) maleimide. Among them, DCOIT, tralopyryl and medetomidine are preferable. These organic antifouling agents (E) may be used alone or in combination of two or more.

When the coating composition of the present invention contains the organic antifouling agent (E), the content of the organic antifouling agent (E) in the coating composition is usually preferably from 0.05 to 20% by mass, more preferably from 0.1 to 5% by mass. When the content of the organic antifouling agent (E) is within the above range, good stain resistance can be imparted to the coating film while maintaining good physical properties of the coating film.

[Monocarboxylic acid compound (F)]

In the present invention, a monocarboxylic acid compound (F) may be used for the purpose of improving surface renewability and water resistance of a coating film.

As the monocarboxylic acid compound (F), for example, a compound in which a carboxy group is substituted with a saturated or an unsaturated aliphatic hydrocarbon group having 10 to 40 carbon atoms or a saturated or unsaturated alicyclic hydrocarbon group having 3 to 40 carbon atoms A compound in which one carboxyl group is substituted, or a compound in which one carboxyl group is substituted in these substituents is preferable.

Among them, trimethyl isobutenyl cyclohexenecarboxylic acid compound, versatile acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linoleic acid, abietic acid, neoabietic acid, pimaric acid, dehydroabietic acid, Ricostearic acid, naphthenic acid, and metal salts thereof are preferable. In addition, rosins mainly composed of rosin acid such as abietic acid, palastric acid, and isophthalic acid are also preferable.

Examples of the trimethylisobutylcyclohexenecarboxylic acid include the reaction product of 2,6-dimethylocta-2,4,6-triene and methacrylic acid, which is 1,2,3-tri Methyl-5- (2-methylprop-1-en-1-yl) cyclohexa- En-1-yl) cyclohex-3-ene-1-carboxylic acid as a main component (85 mass% or more).

When the coating composition of the present invention contains the monocarboxylic acid compound (F), the content of the monocarboxylic acid compound (F) in the coating composition is preferably from 0.1 to 50 mass%.

[Anti-sagging - Anti-settling agent (G)]

In the present invention, the anti-sag preventing agent (G) may be used for the purpose of adjusting the viscosity of the coating composition. Examples of the anti-settling agent (G) include organic clay waxes (stearate salts of Al, Ca and Zn, lecithin salts and alkyl sulfonates), organic waxes (polyethylene wax, oxidized polyethylene wax, amide wax, polyamide wax , Hydrogenated castor oil free wax), a mixture of an organic clay wax and an organic wax, and synthetic fine silica.

Anti-sagging-anti-settling agent (G) may be a commercially available product, for example, "Diparron 305", "Diparron 4200-20" and "Diparron A630-20X" manufactured by Gusumoto Chemical Co., &Quot; and the like.

When the coating composition of the present invention contains the anti-sag preventing agent (G), the content of the anti-sagging agent (G) in the coating composition is preferably from 0.01 to 10 mass%, more preferably from 0.1 to 3 mass% desirable.

[Plasticizer (H)]

A plasticizer (H) may be used in the coating composition of the present invention for the purpose of improving crack resistance and water resistance of the coating film and suppressing discoloration.

Examples of the plasticizer (H) include n-paraffin, chlorinated paraffin, terpene phenol, tricresyl phosphate (TCP), polyvinyl ethyl ether and the like. Among them, chlorinated paraffin and terpene phenol are preferable, and chlorinated paraffin is more preferable. These plasticizers may be used alone or in combination of two or more.

As the plasticizer (H), a commercially available product may be used. As the n-paraffin, for example, "n-paraffin" manufactured by Nippon Petrochemical Co., Ltd., and for the chlorinated paraffin, "Toyoparax A -40 / A-50 / A-70 / A-145 / A-150 &quot;

When the coating composition of the present invention contains the plasticizer (H), the content of the plasticizer (H) in the coating composition is preferably from 0.1 to 10% by mass.

[Dehydrating agent (I)]

In the present invention, a dehydrating agent (I) may be used for the purpose of improving the storage stability of the coating composition.

Examples of the dehydrating agent (I) include orthoesters such as zeolite, alumina and orthoformic acid alkyl ester, orthoboric acid, and isocyanates, which are known as alkoxysilane and the generic name of "Molecular Sieve" . These dehydrating agents may be used alone or in combination of two or more.

When the coating composition of the present invention contains the dehydrating agent (I), the content of the dehydrating agent (I) in the coating composition is preferably from 0.1 to 10 mass%, more preferably from 0.2 to 2 mass%. When the content of the dehydrating agent (I) is within the above range, the storage stability of the coating composition can be maintained favorably, and generation of a paint such as secondary agglomeration of the hydrophilic polymer (B) can be suppressed.

&Lt; Method for producing coating composition for forming frictional resistance reducing coating film >

The coating composition of the present invention can be prepared using the same apparatus, means, and the like as the known general antifouling paints. Concretely, the hydrophilic polymer (B) is added to the solution or dispersion obtained by mixing the previously prepared solution of the hydrolyzable polymer (A) and, if necessary, other additives, etc., And the like.

[Friction Resistance Reducing Coating Film and Corresponding Coating Film]

The coating composition of the present invention is used for forming a frictional resistance reducing coating film. That is, the friction-reducing coating film of the present invention is obtained by curing the coating composition of the present invention. Specifically, for example, by applying the coating composition of the present invention to a substrate or the like, followed by drying, a frictional resistance reducing coating film can be obtained.

Examples of the method of applying the coating composition of the present invention include known methods such as a method using a brush, a roller and a spray.

The coating composition applied by the above-mentioned method is allowed to stand for about 0.5 to 14 days under the condition of, for example, 25 캜, and hardened to obtain a coating film. On the other hand, the coating composition may be cured by blowing under heating.

The thickness after curing of the frictional resistance reducing coating film is preferably about 30 to 1,000 占 퐉, for example, from the viewpoint of improving the coating film strength and reducing the frictional resistance. As a method of producing the frictional resistance reducing coating of this thickness, there is a method of applying the coating composition at a thickness of usually 10 to 300 m, preferably 30 to 200 m per application, once to several times per application.

The coated film-attached substrate of the present invention has the above-mentioned frictional resistance reducing coating film on a substrate.

The coated film-adhering base material of the present invention can be obtained by, for example, a step of applying or impregnating a base material to a base material to obtain a coating material or impregnation material, and a step of curing the coating material applied or impregnated to the base material by the base material And a step of attaching a coating film obtained by curing the coating composition to a substrate.

Specific examples of the method of applying or impregnating the coating composition to the substrate include a method of sufficiently stirring the coating composition and then applying or impregnating the coating composition onto the substrate by spraying or other means.

On the other hand, as a method of curing the coating composition applied or impregnated onto the substrate, a method of curing the coating composition by drying the coating or impregnation is preferable. Specifically, the coating composition is preferably cured in air at room temperature for about 0.5 to 14 days, And drying the coated material or impregnated material by forcibly blowing under forced or heated conditions. By such a method, the coated film-attached substrate of the present invention having the above-described frictional resistance reducing coating film on a substrate can be easily produced.

As a method for attaching a coating film obtained by curing a coating composition to a substrate, there is a method in which a film including a coating film obtained by curing a coating composition is stuck to a substrate using a known technique described in, for example, Japanese Patent Application Laid- Method. With this method, it is possible to manufacture a coated film-attached substrate in which the substrate is coated with the frictional resistance reducing coating film.

INDUSTRIAL APPLICABILITY The coating composition of the present invention is capable of maintaining the function of reducing the frictional resistance of the substrate for a long period of time in a wide range of industrial fields such as ships, fisheries, pipelines, water systems, diving equipment, underwater propellants, power generation, . Examples of such a base material include ships (such as large steel wires such as container ships and tankers, fishing boats, FRP ships, ship hulls such as yachts, newbuildings or watercraft), fishery materials (ropes, fishing nets, Underwater structures such as oil and gas pipelines, water piping, circulating water pipes, diver suits, underwater glasses, oxygen bombs, swimwear, torpedoes, thermal power plants and nuclear power plant water supply and drainage systems, Etc.), Mega float, Manan road, submarine tunnel, harbor facility, sludge diffusion preventing film of various marine civil engineering works such as canal and waterway. Of these, ships are preferred as the substrate.

The coating composition of the present invention may be directly applied to the substrate or impregnated. Even when a material such as a water discharge hole of a nuclear power plant, a mega float, or a vessel is directly applied to a substrate such as fiber reinforced plastic (FRP), steel, wood, aluminum alloy, etc., the coating composition according to the present invention, Can be adjusted so as to improve the adhesion to the substrate.

The substrate to which the coating composition of the present invention is to be applied may have a coating film already formed on its surface. That is, the coating composition of the present invention may be applied to the surface of a base material previously coated with a base material (undercoat) such as a rust preventive agent or a primer. The coating composition of the present invention may be applied on the surface of a base material already coated with a conventional coating material or coated with the coating material composition of the present invention. The kind of the coating film to which the coating composition according to the present invention is directly touched is not particularly limited.

Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

On the other hand, the "solid content" of each component used in the examples refers to a component excluding the volatile component contained as a solvent in each component and is considered to be obtained by drying each component in a hot air drier at 125 ° C for 1 hour.

&Lt; Production of hydrolysable polymer (A) >

Preparation Example 1: Preparation of hydrolyzable group-containing monomer (a0)

In the production of the hydrolyzable polymer (A), first, the hydrolyzable group-containing monomer (a0) was prepared as follows.

85.4 parts by mass of propylene glycol monomethyl ether (PGM) and 40.7 parts by mass of zinc oxide were put into a four-necked flask equipped with a condenser, a thermometer, a dropping funnel and a stirrer, and the mixture was heated to 75 ° C while stirring. Subsequently, a mixture consisting of 43.1 parts by mass of methacrylic acid (MAA), 36.1 parts by mass of acrylic acid (AA) and 5.0 parts by mass of water was added dropwise from the dropping funnel over a period of 3 hours at a constant rate. After completion of the dropwise addition, the reaction solution became transparent from the milky white state. After further stirring for 2 hours, 36.0 parts by mass of propylene glycol monomethyl ether was added to obtain a reaction solution containing the monomer (a0) containing a hydrolysable group. The solid content of the reaction solution was 44.8 mass%.

[Preparation Example 1: preparation of solution (A1) of hydrolysable polymer (metal ester group-containing copolymer)]

15.0 parts by mass of propylene glycol monomethyl ether (PGM) and 57.0 parts by mass of xylene were fed into a four-necked flask equipped with a stirrer, a thermometer, a thermometer, a dropping funnel, and the mixture was heated to 100 ° C while stirring. Subsequently, 52.0 parts by mass of the reaction liquid of the hydrolyzable group-containing monomer (a0) obtained in Preparation Example 1, 1.0 part by mass of methyl methacrylate (MMA), 66.2 parts by mass of ethyl acrylate (EA) , 2.5 parts by mass of azobisisobutyronitrile (AIBN) (manufactured by Nihon Hydrazine Kogyo K.K.) and 5 parts by mass of azobisisobutyronitrile (AMBN) (manufactured by Nihon Hydrazine Industry Co., Ltd. ), 1.0 part by mass of? -Methylstyrene dimer ("Nopmer MSD" manufactured by Nippon Oil and Fats Co., Ltd.) and 10.0 parts by mass of xylene was added dropwise at a constant rate over a period of 6 hours from a dropping funnel. After completion of the dropwise addition, 0.5 part by mass of t-butylperoctoate (TBPO) and 7.0 parts by mass of xylene were added dropwise over 30 minutes and further stirred for 1 hour and 30 minutes. Then, 4.4 parts by mass of xylene was added to obtain a hydrolyzable polymer (A1) having no insoluble matter and having a pale yellow color and a clear, water-insoluble and water-insoluble polymer. Table 1 shows the properties of the obtained hydrolyzable polymer solution (A1).

[Production Example 2: preparation of solution (A2) of hydrolyzable polymer (metal ester group-containing copolymer)] [

The monomer charge amount in Preparation Example 1 was changed to 48.3 parts by mass of the reaction liquid of the hydrolyzable group-containing monomer (a0), 12.2 parts by mass of methyl methacrylate (MMA), and 62.0 parts by mass of ethyl acrylate (EA) To obtain a solution (A2) of a light yellow transparent, hydrolyzable polymer (metal ester group-containing copolymer) free of insoluble matter containing a hydrolyzable polymer (a metal ester group-containing copolymer). The properties of the obtained hydrolyzable polymer solution (A2) are shown in Table 1.

The Gardner viscosity and the weight average molecular weight (Mw) of the obtained hydrolyzable polymer solutions (A1) and (A2) were measured as follows.

&Lt; Measurement conditions of Gardner viscosity >

The Gardner viscosity was measured at a resin content concentration of 35 mass% and 25 deg. C according to 4.3 of JIS K7233 as described in Japanese Patent Laid-Open No. 2003-55890.

&Lt; Measurement of weight average molecular weight (Mw) of hydrolysable polymer (A) >

The weight average molecular weight (Mw) of the hydrolysable polymer (A) was measured by GPC (gel permeation chromatography) under the following conditions.

Apparatus: &quot; HLC-8320GPC &quot; (manufactured by Tosoh Corporation)

Column: Two "TSKgel SuperAWM-H" and one "TSKgel SuperAW2500" were connected (all manufactured by TOSOH CORPORATION, inner diameter 6 mm / length 15 cm

Eluent: N, N-dimethylformamide (DMF) (20 mM lithium bromide added)

Flow rate: 0.600 ml / min

Detector: RI

Column thermostat temperature: 40 ° C

Standard material: polystyrene

Preparation of a sample: A small amount of calcium chloride was added to the polymer solutions (A1) and (A2) prepared in each Production Example and dehydrated, and then filtered with a membrane filter to obtain a GPC measurement sample.

&Lt; Preparation of coating composition >

· Ingredients

The blending components used in the coating composition are shown in Tables 2 and 3, and the properties and the like of the hydrophilic polymer (B) are shown in Table 4.

* 1: The average molecular weight was measured by GPC-MALS. OHpak SB-806HQ "manufactured by Showa Denko Co., Ltd. was used for separation.

As a differential refractive index detector, "RID20A" manufactured by Shimadzu Corporation was used, and "DAWN HELEOS II" manufactured by Wyatt Technology was used as a light scattering detector.

A 50 mM aqueous solution of sodium nitrate was used as the eluent, and the measurement was carried out at a flow rate of 0.8 mL / min and a column temperature of 40 캜.

* 2: Pretreatment was carried out by jet mill pulverization and classification with a mesh of 38 micron mesh.

* 3: The average particle diameter is 50% diameter (median diameter) measured by a dry method using "SALD-2200" manufactured by Shimadzu Corporation.

[Examples 1 to 14 and Comparative Examples 1 to 2]

· Preparation of Coating Composition

Each of the ingredients was mixed and stirred with the ingredients (parts by mass) shown in Tables 5 and 6 to obtain a paint composition. On the other hand, the blending amounts of the components shown in Table 5 and Table 6 represent the blending amount as it is.

The contents (mass%) of the hydrolyzable polymer (A), the hydrophilic polymer (B) and the pigment volume concentration (PVC) in the solid content of the paints of the obtained coating compositions are shown in Tables 5 and 6, respectively.

[Evaluation of coating film durability]

The coating compositions of Examples and Comparative Examples shown in Tables 5 and 6 were applied to a vinyl chloride plate (length 50 mm x width 50 mm) at room temperature using a film applicator with a gap of 0.7 mm so that the dry film thickness would be 100 m. After one day at room temperature, the test plate with the coating film was subjected to rotary dipping for 7 days at a speed condition in which the water flow rate on the test coat film corresponded to about 10 knots in seawater whose temperature was adjusted to 23 ° C, Using a cutter knife, the cuts leading to the substrate were vertically crossed, and the collapse of the coating film around the cut portion was observed, and the following scores were given.

〔Evaluation standard〕

No coat collapse or peeling occurred at any two points.

The collapse or peeling of the coating film occurred in the vicinity of the one-point cross portion.

The coating film collapsed from the periphery of the zero point cut portion.

[Evaluation of Friction Resistance]

An epoxy-based paint (brand name: Banno 500N, manufactured by Chugoku Kogyo Co., Ltd.) was applied as an undercoat on the outer surface of a cylinder made of vinyl chloride having a diameter of 310 mm so as to have a film thickness of 100 m when dried, The coating compositions of the examples and comparative examples shown in Tables 5 and 6 were coated at room temperature using a sprayer to a dry film thickness of 100 mu m. After one day at room temperature, the test cylinder was immersed in seawater whose temperature was adjusted to 23 DEG C for 7 days under the condition that the water flow rate on the test coat film corresponded to about 10 knots in calculation, and then the frictional resistance was evaluated I did.

The frictional resistance of the coated film was evaluated using a double cylindrical resistance measuring device. The double cylindrical resistance measuring device comprises two inner and outer cylinders, and an inner cylinder formed on the outer surface of the outer cylinder filled with artificial seawater and provided with a coating film of the sample to be measured is provided. When the outer cylinder is rotated to generate rotating water The torque applied to the cylinder is measured.

The film adhesion test cylinders of the Examples and Comparative Examples prepared above were used as the inner cylinder and the measured torque stress was compared with the reference torque stress obtained by using the inner cylinder of unpatterned area and the reduction ratio was calculated as the frictional resistance reduction rate% Are shown in Tables 5 and 6. &lt; tb &gt; &lt; TABLE &gt; Friction resistance The larger the reduction rate% is, the higher the effect of reducing the frictional resistance by the coating film is.

The measurement was carried out at a temperature of 23 DEG C under a speed condition in which the rotational speed of the outer cylinder was set to 400 rpm and the water flow rate on the test coat film corresponded to about 10 knots in calculation.

As is apparent from the results of Examples and Comparative Examples, the present invention can provide a coating composition for forming a friction-reducing coating film capable of sufficiently maintaining the physical properties and the frictional resistance reducing effect of a coating film over a long period of time in water, A coating film for reducing frictional resistance, and a coating film-attached substrate having the coating film on a substrate.

The coating composition of the present invention can form a frictional resistance reducing coating film on a surface of a structure such as a vessel propelling it in water, a surface of a structure placed in water or the like, and an inner surface of a pipe structure such as a pipeline, It is possible to sufficiently maintain the physical properties and the frictional resistance reducing effect of the coating film.

Claims (12)

(A) and a hydrophilic polymer (B) having a weight average molecular weight of 500,000 or more, wherein the pigment volume concentration (PVC) in the solid content of the paint is less than 20% by volume. The method according to claim 1,
Wherein the content of the hydrolyzable polymer (A) in the solid content of the paint is 50 to 98 mass%. 3. The method according to claim 1 or 2,
Wherein the content of the hydrophilic polymer (B) in the solid content of the coating material is 1 to 45 mass%. 4. The method according to any one of claims 1 to 3,
Wherein the hydrolyzable polymer (A) has a metal ester group. 5. The method of claim 4,
Wherein the metal ester group is a divalent metal ester group represented by the following formula (I).

(Wherein M represents a metal and * represents an arbitrary organic group). 6. The method according to any one of claims 1 to 5,
Wherein the hydrophilic polymer (B) has a structural unit derived from one hydrophilic group-containing unsaturated monomer or a structural unit derived from at least two hydrophilic group-containing unsaturated monomers. The method according to claim 6,
Wherein the hydrophilic group-containing unsaturated monomer is at least one selected from a nonionic group-containing unsaturated monomer, an anionic group-containing unsaturated monomer and a cationic group-containing unsaturated monomer. 8. The method according to any one of claims 1 to 7,
Wherein the hydrophilic polymer (B) has a weight average molecular weight (Mw) of 3,000,000 or more. A friction resistance reducing coating film obtained by curing the coating composition according to any one of claims 1 to 8. A coating film-attached substrate having the friction-resistance-lowering coating film according to claim 9 on a substrate. 11. The method of claim 10,
Wherein the substrate is a ship. (1) a step of applying or impregnating the coating composition according to any one of claims 1 to 8 to a substrate to obtain a coated or impregnated substrate, and drying the coated or impregnated substrate, (2) for curing the composition, a method for producing a friction-reducing coating film-attached base material