JP6596802B2 - COATING COMPOSITION FOR COATING FORM WITH REDUCED FRICTION RESISTANCE, COATING AND SUBSTRATE WITH COATING - Google Patents

Description

  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 using the same, and a substrate with a coating film having the coating film on a substrate.

  When friction occurs between the surface of a structure and the liquid, such as when a structure such as a ship propels water underwater or when liquid is transported through a pipe structure such as a pipeline, a large amount of energy is generated due to frictional resistance. Is consumed. As a method for reducing this frictional resistance, for example, there is a method using the so-called Toms effect in which a polymer compound, fiber, or the like is added to a liquid to suppress generation of turbulent flow near the surface of the structure. And, as a method using this Toms effect, for example, a technique for improving the renewability of the coating film by adding a hydrolyzable polymer to the coating film and facilitating the sustained release of a polymer compound or the like from the coating film Is mentioned.

  More specifically, in Patent Document 1, a water-soluble polymer (a) such as polyethylene oxide and a resin having a coating film renewability such as a metal ester-containing acrylic resin or a triorganosilyl (meth) acrylate-containing resin ( A coating composition containing b) has been proposed. In Patent Document 2, a self-cleaning resin, a water-soluble polymer, a pigment, and a mixture of any one or more selected from the group consisting of a zinc acrylate polymer, a copper acrylate polymer, and a silyl acrylate polymer A frictional resistance reducing coating composition containing a solvent has been proposed.

JP 2001-342432 A International Publication No. 2011/34246

  Regarding coating films for reducing frictional resistance, including Patent Documents 1 and 2, coating films that exhibit practically sufficient performance are widely spread despite the fact that many studies have been made so far. It has not reached. The main factors are as follows. That is, when a coating film containing a hydrolyzable polymer as a binder and a hydrophilic polymer compound that exhibits the Toms effect is immersed in water, the coating film is brought into the coating film due to the hydrophilicity of the polymer compound. Absorption of water is promoted, resulting in a volume change due to swelling of the polymer compound and a problem that the coating film cannot maintain sufficient strength in water due to a rapid hydrolysis reaction inside the coating film. At the same time, there is also a problem that the frictional resistance cannot be reduced over a long period of time because the hydrolysis reaction proceeds promptly on the surface of the coating film.

The present invention has been made in view of the above circumstances, and is a paint for forming a frictional resistance-reducing coating film that can sufficiently maintain the physical properties of the coating film and the frictional resistance reduction effect over a long period of time in water. It is an object to provide a composition.
Moreover, this invention makes it a subject to provide the coating film for frictional resistance reduction which hardened the said coating composition, the base material with a coating film which has the said coating film on a base material, and this manufacturing method.

  As a result of extensive studies by the inventors, a paint composition in which a hydrolyzable polymer and a hydrophilic polymer having a specific weight average molecular weight are used in combination, and the pigment volume concentration (PVC) is adjusted to a specific range. It has been found that a coating film formed from a product maintains sufficient strength in water for a long period of time. Furthermore, the coating film unexpectedly found that the effect of reducing frictional resistance was dramatically improved 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] The hydrolyzable polymer (A) and the hydrophilic polymer (B) having a weight average molecular weight of 500,000 or more are contained, and the pigment volume concentration (PVC) in the solid content of the paint is less than 20% by volume. A certain coating composition for forming a frictional resistance-reducing coating film.
[2] The coating composition according to [1], wherein the content of the hydrolyzable polymer (A) in the solid content of the coating is 50 to 98% by mass.
[3] The coating composition according to [1] or [2], wherein the content of the hydrophilic polymer (B) in the coating solid content is 1 to 45% by 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).

(In the formula, M represents a metal, and * represents that it is linked to an arbitrary organic group.)
[6] A homopolymer in which the hydrophilic polymer (B) has a structural unit derived from one type of hydrophilic group-containing unsaturated monomer, or two or more types of hydrophilic group-containing unsaturated monomers The coating composition according to any one of the above [1] to [5], which is a copolymer having a structural unit derived from.
[7] The hydrophilic group-containing unsaturated monomer is selected from a nonionic group-containing unsaturated monomer, an anionic group-containing unsaturated monomer, and a cationic group-containing unsaturated monomer The coating composition according to [6], which is a seed or more.
[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 frictional resistance-reducing coating film obtained by curing the coating composition according to any one of [1] to [8].
[10] A base material with a coating film having the frictional resistance reducing coating film according to [9] above on the base material.
[11] The coated substrate according to [10], wherein the substrate is a ship.
[12] A step (1) of obtaining an applied body or an impregnated body by applying or impregnating a coating composition according to any one of [1] to [8] to a substrate, and the applied body or impregnated body The manufacturing method of the base material with a frictional resistance reduction coating film which has the process (2) which hardens the said coating composition by drying.

ADVANTAGE OF THE INVENTION According to this invention, the coating composition for frictional resistance reduction coating film formation which can fully maintain the physical property of a coating film and a frictional resistance reduction effect in water for a long period of time can be provided.
Moreover, this invention can provide the coating film for frictional resistance reduction which hardened the said coating composition, the base material with a coating film which has the said coating film on a base material, and this manufacturing method.

[Coating composition for forming a frictional resistance-reducing coating film]
The coating composition for forming a frictional resistance-reducing coating film according to the present invention contains a hydrolyzable polymer (A) and a hydrophilic polymer (B) having a weight average molecular weight of 500,000 or more. It is a coating composition for forming a reduced frictional resistance coating film having a pigment volume concentration (PVC) of less than 20% by volume.

<Hydrolyzable polymer (A)>
The coating composition for forming a reduced frictional resistance coating film of the present invention contains a hydrolyzable polymer (A). When the hydrolyzable polymer (A) is used in the present invention, the hydrolyzable polymer (A) present on the coating surface in water is gradually hydrolyzed and the coating surface is sequentially renewed. The molecule (B) is easily released, and the effect of reducing frictional resistance is exhibited.

The hydrolyzable polymer (A) in the present invention has a hydrolyzable group, and is preferably derived from the hydrolyzable group-containing monomer (a0) in the hydrolyzable polymer (A). It has a structural unit. 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 bonding a metal and a carboxylic acid. Further, the “polyvalent metal ester group” or “divalent metal ester group” described later refers to a group formed by combining a polyvalent metal or divalent metal and a carboxylic acid.
The hydrolyzable group of the hydrolyzable polymer (A) in the present invention is preferably a metal ester group, more preferably a polyvalent metal ester group, from the viewpoint of expressing a frictional resistance reducing effect over a long period of time. The divalent metal ester group represented by (I) is more preferable.

(In the formula, M represents a metal, and * represents that it is linked to 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, nickel, copper, zinc, and the like. Metals belonging to Groups 10 to 12 of the periodic table are preferred, copper and zinc are more preferred, and zinc is still more preferred.

The hydrolyzable polymer (A) having a metal ester group can be produced, for example, by the following procedure.
First, a mixed liquid obtained by mixing a solvent and a metal component such as zinc oxide is stirred while being heated to about 50 to 80 ° C., and a mixed liquid of organic acid such as methacrylic acid or acrylic acid, and water is added thereto. The hydrolyzable group-containing monomer (a0) is prepared by dropping and further stirring.
Next, a solvent is placed in a newly prepared reaction vessel and heated to about 80 to 120 ° C., and the hydrolyzable group-containing monomer (a0) and a hydrolyzable group-containing monomer (a0) described later are added thereto. ), A hydrolyzable polymer (A) having a metal ester group can be obtained by dropping a mixed liquid of a monomer, a polymerization initiator, a chain transfer agent, a solvent, and the like and performing a polymerization reaction.
In addition, the ratio of each content (mass) of the structural unit derived from each monomer in the hydrolyzable polymer (A) is the ratio of the charged amount (mass) of each monomer used for the polymerization reaction. Can be regarded as the same.

Examples of monomers other than the hydrolyzable group-containing monomer (a0) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and butyl (meth). Acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl ( (Meth) acrylate, 3,5,5-trimethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) ) Alkyl (meth) acrylates such as acrylates, aryl (meth) acrylate or aralkyl (meth) acrylate;
2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, methoxypropyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) Alkoxyalkyl (meth) acrylates or aryloxyalkyl (meth) acrylates such as acrylate, isobutoxybutyl diglycol (meth) acrylate, 2-phenoxyethyl (meth) acrylate;
Hydroxy such as hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate Alkyl (meth) acrylates;
And organosiloxane group-containing (meth) acrylates. These monomers may be used alone or in combination of two or more.
Among the monomers other than the hydrolyzable group-containing monomer (a0) described above, alkyl (meth) acrylate and alkoxyalkyl (meth) acrylate are preferable, methyl methacrylate, ethyl acrylate, butyl acrylate, 2-methoxyethyl acrylate 2-methoxyethyl methacrylate is more preferable.
The hydrolyzable polymer (A) of the present invention may be a homopolymer having a structural unit derived from one type of hydrolyzable group-containing monomer (a0), or two or more types of hydrolyzable polymers. A copolymer having a structural unit derived from a group-containing monomer (a0), a structural unit derived from one or more hydrolyzable group-containing monomers (a0), and one or more hydrolyzable groups A copolymer having a structural unit derived from a monomer other than the monomer (a0) may be used.
In the present invention, “(meth) acrylate” means “acrylate or methacrylate”. Other similar notations have the same meaning.

There is no restriction | limiting in particular as a polymerization initiator which can be used for manufacture of a hydrolysable polymer (A), Various radical polymerization initiators can be used. Specifically, benzoyl peroxide, hydrogen peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, potassium persulfate, sodium persulfate, 2,2′-azobis (isobutyronitrile) [AIBN], 2,2 Examples include '-azobis (2-methylbutyronitrile) [AMBN], 2,2'-azobis (2,4-dimethylvaleronitrile) [ADVN], and tert-butyl peroctoate [TBPO]. These polymerization initiators may be used alone or in combination of two or more. These radical polymerization initiators may be added to the reaction system only at the start of the reaction, or may be added to the reaction system both at the start of the reaction and during the reaction.
As for the usage-amount of the polymerization initiator in manufacture of a hydrolyzable polymer (A), 5-20 mass parts is preferable with respect to a total of 100 mass parts of each said monomer.

There is no restriction | limiting in particular as a chain transfer agent which can be used for manufacture of a hydrolyzable polymer (A), For example, (alpha) -methylstyrene dimer, thioglycolic acid, a diterpene, a terpinolene, (gamma) -terpinene; tert-dodecyl mercaptan And mercaptans such as 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 using a chain transfer agent in manufacture of a hydrolyzable polymer (A), the usage-amount is 0.1-5 mass parts with respect to a total of 100 mass parts of each said monomer.

Examples of the solvent that can be used for producing the hydrolyzable polymer (A) include propylene glycol monomethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monobutyl ether. And polyhydric alcohol monoalkyl ethers; aromatic hydrocarbon solvents such as toluene, xylene and mesitylene; water and the like.
When using a solvent in manufacture of a hydrolysable polymer (A), there is no restriction | limiting in particular in the usage-amount, However, 5-150 mass parts is preferable with respect to 100 mass parts in total of each said monomer.

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, 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 also improved.
In addition, the weight average molecular weight (Mw) of a hydrolyzable polymer (A) points out the value of the gel permeation chromatography (GPC) measured by the method as described in an Example.

The content of the hydrolyzable 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, and still more preferably 65% by mass. % Or more, more preferably 70% by mass or more, and preferably 98% by mass or less, more preferably 95% by mass or less, still more preferably 90% by mass or less, still more preferably 85% by mass or less, and still more. Preferably it is 80 mass% or less. When the content of the hydrolyzable polymer (A) is within the above range, an excellent frictional resistance reduction effect can be obtained over a long period, and the strength of the coating film can be maintained over a long period. .
In the present invention, the “solid content of the coating composition” refers to a component excluding an organic solvent (D) described later and a volatile component contained as a solvent in each component, and the “content in the solid content of the coating composition” “Amount” is regarded as the content in the solid content obtained by drying the coating composition in a hot air dryer at 125 ° C. for 1 hour. In the present specification, “solid content of the coating composition” may be abbreviated as “paint solid content”.

<Hydrophilic polymer (B)>
The coating composition of the present invention comprises 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 from the coating composition. contains.
When the hydrophilic polymer (B) is used in the coating composition of the present invention, the development of the turbulent vortex in the vicinity of the coating film is suppressed by the transfer of the hydrophilic polymer (B) from the inside of the coating film to the coating film surface. Therefore, frictional resistance in water can be reduced.
The “hydrophilic polymer” in the present invention means a hydroxy group, an amino group, an amide group, an alkoxy group, an ether group (including an alkylene oxide unit), a carboxy group, an ester group, a sulfonic acid group, And a polymer compound having at least one hydrophilic group such as a quaternary ammonium base.

The hydrophilic polymer (B) in the present invention is preferably at least one selected from a hydrophilic synthetic polymer (B1) and a 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. Among these, hydrophilic group-containing vinyl polymers, and Polyalkylene oxide is preferred. These hydrophilic synthetic polymers (B1) may be used alone or in combination of two or more.

(Hydrophilic group-containing vinyl polymer)
Examples of the hydrophilic group-containing vinyl polymer include 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.

Nonionic group-containing unsaturated monomers include hydroxy groups such as (meth) acrylamide, hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and methoxypolyethylene glycol mono (meth) acrylate, amide groups or Ether group containing (meth) acrylate etc. are mentioned.
In the present invention, “(meth) acrylamide” means “acrylamide or methacrylamide”.

Examples of the anionic group-containing unsaturated monomer include carboxy group-containing unsaturated monomers such as (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, and crotonic acid, styrenesulfonic acid, and 3- (methacryloyl). And sulfonic acid group-containing unsaturated monomers such as oxy) propanesulfonic acid and acrylamidepropanesulfonic acid.
These anionic group-containing unsaturated monomers may be used partially or completely neutralized. The neutralization may be performed as a monomer, or may be neutralized after the polymer is formed.
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 cationic group-containing unsaturated monomer include one or more selected from an amino group-containing unsaturated monomer and a quaternary ammonium base-containing unsaturated monomer.
Examples of the amino group-containing unsaturated monomer include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N- Diethylaminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) ) Acrylamide, 2-vinylpyridine, 4-vinylpyridine, and structures obtained by neutralizing these with an acid represented by H ⁺ X ⁻ .
As the quaternary ammonium salt group-containing unsaturated monomer, X ^- a with counterions (meth) acryloyloxyethyl trimethyl ammonium (meth) acryloyloxy propyl trimethyl ammonium (meth) acryloyl-aminoethyl trimethylammonium, ( And (meth) acryloylaminopropyltrimethylammonium, diallyldimethylammonium, 1-ethyl-4-vinylpyridinium, 1,2-dimethyl-5-vinylpyridinium, and the like.
X ⁻ represents an anion, preferably a halide ion, and more preferably a chloride ion.

The hydrophilic synthetic polymer (B1) in the present invention may be a homopolymer having a structural unit derived from one type of hydrophilic group-containing unsaturated monomer, or two or more types of hydrophilic groups. A copolymer having a structural unit derived from the contained unsaturated monomer may be used.
The hydrophilic group-containing unsaturated monomer in the present invention is 1 selected from a nonionic group-containing unsaturated monomer, an anionic group-containing unsaturated monomer, and a cationic group-containing unsaturated monomer. One or more species are preferred, one or more species selected from nonionic group-containing unsaturated monomers and anionic group-containing unsaturated monomers are more preferred, and one or more species selected from acrylamide, acrylic acid and salts thereof are preferred. Further preferred.
In the present invention, “one or more selected from nonionic group-containing unsaturated monomers, anionic group-containing unsaturated monomers, and cationic group-containing unsaturated monomers” means, for example, “ 1 or more selected from nonionic group-containing unsaturated monomers, 1 or more selected from anionic group-containing unsaturated monomers, and 1 selected from cationic group-containing unsaturated monomers "One or more species" and "one or more selected from nonionic group-containing unsaturated monomers and one or more mixtures selected from anionic group-containing unsaturated monomers" or "nonionic It also means “one or more selected from group-containing unsaturated monomers and one or more mixtures selected from cationic group-containing unsaturated monomers”.

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

Furthermore, the hydrophilic synthetic polymer (B1) may be a copolymer of a hydrophilic group-containing unsaturated monomer and other monomers other than that.
Examples of other monomers include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 4-tert-butylstyrene, and 5-tert-butyl-2- And aromatic vinyl such as methylstyrene.
In addition, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid alkyl esters such as isooctyl acid and n-octyl (meth) acrylate may be mentioned.
When the hydrophilic synthetic polymer (B1) contains a structural unit derived from another monomer, the content is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass. It is as follows.

(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 copolymers and polyethylene oxide are preferred, and polyethylene oxide is more preferred.

  What is marketed can be used as a hydrophilic synthetic polymer (B1). Commercially available products include, for example, “polyacrylamide” manufactured by Polyscience, Inc., “poly (acrylamide-acrylic acid) copolymer”, “PEO18” (PEO) manufactured by Sumitomo Seika Co., Ltd., and Meisei Chemical Co., Ltd. ) “Alcox EP-10” (PEO-PPO), “Alcox EP-20” (PEO-PPO).

[Hydrophilic natural product-derived polymer (B2)]
The hydrophilic natural product-derived polymer (B2) in the present invention refers to polymers derived from animals and plants, or those obtained by chemically modifying these polymers.
Examples of the hydrophilic natural product-derived polymer (B2) include fenugreek gum, guar gum, tara gum, locust bean gum (carob bean gum), starch, pullulan, cellulose, xylose, chitin, chitosan, gum arabic, caraya gum, tragacanth gum, alginic acid or Salt, carrageenan (κ, ι, λ type), agar, xanthan gum, welan gum, diyutan gum, gellan gum, succinoglycan, curdlan, hyaluronic acid, dextran, γ-polyglutamic acid or its salt, keratin, silk, nucleic acid , Alkylcelluloses such as methylcellulose (MC), hydroxyalkylcelluloses such as hydroxyethylcellulose (HEC) and hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HP) C) and hydroxyalkyl (alkyl) cellulose such as hydroxyethyl cellulose (HEMC), carboxymethyl cellulose (CMC), cationic cellulose, hydrophobic cellulose, solubilized starch, carboxymethyl starch, and such as propylene glycol alginate. These hydrophilic natural product-derived polymers (B2) may be used alone or in combination of two or more.

  Among these, guar gum, tara gum, locust bean gum, starch, alginic acid or a salt thereof, xanthan gum, welan gum, diyutan gum, gellan gum, succinoglycan, γ-polyglutamic acid or a salt thereof, hydroxypropyl cellulose (HPC), hydroxyethyl Methyl cellulose (HEMC), hydroxypropyl methyl cellulose (HPMC), and carboxymethyl cellulose (CMC) are preferred, guar gum, tara gum, locust bean gum, xanthan gum, welan gum, dieutan gum, γ-polyglutamic acid or a salt thereof, hydroxypropyl cellulose (HPC) ), Hydroxyethylmethylcellulose (HEMC), hydroxypropylmethylcellulose (HPMC), and carboxymethyl Cellulose (CMC) is more preferable, and guar gum, xanthan gum, diutane gum, hydroxyethyl methylcellulose (HEMC), and hydroxypropyl methylcellulose (HPMC) are still more preferable.

The hydrophilic polymer (B) may be either solid or liquid at 23 ° C., but is preferably solid at 23 ° C.
In the case where the hydrophilic polymer (B) is solid at 23 ° C., the average particle diameter is improved from the viewpoint of improving the workability during the production of the coating composition, the coating workability, and the smoothness of the resulting coating film. Preferably it is 0.01 μm or more, more preferably 0.1 μm or more, still more preferably 1 μm or more, even more preferably 3 μm or more, still more preferably 5 μm or more, and preferably 200 μm or less, more preferably 100 μm or less, More preferably, it is 50 μm or less. In addition, the average particle diameter of hydrophilic polymer (B) points out a 50% diameter (median diameter), and can be measured by the method as described in an Example.
The average particle size of the hydrophilic polymer (B) used in the present invention preferably has the average particle size both before blending into the coating composition and in the coating composition. That is, it is preferable that the hydrophilic polymer (B) has low solubility or no solubility in the hydrolyzable polymer (A) from the viewpoint of suppressing an increase in the viscosity of the coating composition.

From the viewpoint of reducing frictional resistance, the weight average molecular weight (Mw) of the hydrophilic polymer (B) is 500,000 or more, preferably 1,000,000 or more, more preferably 1,500,000 or more, More preferably 1,800,000 or more, still more preferably 2,000,000 or more, still more preferably 2,500,000 or more, still more preferably 3,000,000 or more, and even more preferably 3,500. , 000,000 or more, more preferably 4,000,000 or more, still more preferably 4,500,000 or more, and from the viewpoint of reducing the burden on the environment, preferably 100,000,000 or less, more Preferably 20,000,000 or less, more preferably 15,000,000 or less, and even more preferably 12,000,000 or less. It is.
The “weight average molecular weight” of the hydrophilic polymer (B), and the “number average molecular weight” and “Z average molecular weight” described later refer to those 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 usually preferably 1 to 10, and the number average molecular weight of the hydrophilic polymer (B). From the viewpoint of reducing frictional resistance, (Mn) is preferably 100,000 or more, more preferably 300,000 or more, still more preferably 1,000,000 or more, still more preferably 2,000,000 or more, more More preferably, it is 3,000,000 or more, and preferably 100,000,000 or less, more preferably 50,000,000 or less, further preferably 20,000,000 or less, and still more preferably 10,000. 8,000 or less, more preferably 8,000,000 or less.

  The ratio [Mz / Mw] of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) of the hydrophilic polymer (B) is usually preferably 1 to 10, and the Z average molecular weight of the hydrophilic polymer (B) (Mz) is preferably 300,000 or more, more preferably 1,000,000 or more, still more preferably 2,000,000 or more, and preferably 1,000,000 from the viewpoint of reducing frictional resistance. 000,000 or less, more preferably 500,000,000 or less, more preferably 250,000,000 or less, even more preferably 100,000,000 or less, still more preferably 50,000,000 or less, and even more preferably Is 25,000,000 or less.

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 from the viewpoint of reducing frictional resistance. , 000 or less.
The “viscosity average molecular weight (Mv)” refers to a value measured according to JIS-K-7367 using the viscosity method defined in JIS-K-2283 and JIS-Z-8803.
The hydrophilic polymer (B) used in the present invention may form an aggregate in the coating composition, coating film, or water, and the frictional resistance is not required even if each average molecular weight is not in the above range. Although the reduction effect may be exhibited, in the present invention, the molecular weight of the aggregate is only required to be within the range of the aforementioned 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% by mass. % Or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, still more preferably 25% by mass or less, still more preferably 20% by mass or less, still more preferably 15% by mass or less, and still more preferably. It is 10 mass% or less.

  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, from the viewpoint of reducing frictional resistance and improving the coating film strength. Or more, more preferably 5% by mass or more, still more preferably 6.5% by mass or more, and preferably 45% by mass or less, more preferably 30% by mass or less, still more preferably 25% by mass or less, and still more. Preferably it is 20 mass% or less, More preferably, it is 15 mass% or less.

<Pigment (C)>
In the present invention, the pigment (C) may be used for the purpose of coloring the coating film or concealing the base, or for adjusting the coating film strength to an appropriate level and for imparting antifouling properties.
Examples of the pigment (C) include talc, mica, clay, potash feldspar, zinc oxide, calcium carbonate, kaolin, alumina white, white carbon, aluminum hydroxide, magnesium carbonate, barium carbonate, barium sulfate, calcium sulfate, and sulfide. Body pigments such as zinc, petals, colored pigments such as titanium white (titanium oxide), yellow iron oxide, carbon black, naphthol red, and phthalocyanine blue, cuprous oxide, rhodan copper, copper, copper pyrithione, and zinc Antifouling pigments such as pyrithione are listed. Especially, it is preferable that an extender and an antifouling pigment are included, and it is more preferable that talc, zinc oxide, copper pyrithione, and zinc pyrithione are included. These pigments can be used alone or in combination of two or more.

<Pigment volume concentration (PVC) in paint solids>
From the viewpoint of improving the physical properties of the coating film and the effect of reducing frictional resistance over a long period of time, the pigment volume concentration (PVC) in the coating composition solid content of the present invention is less than 20% by volume. 15 volume% or less is preferable, 12 volume% or less is more preferable, 10 volume% or less is further preferable, 8 volume% or less is further more preferable, 7 volume% or less is further more preferable, and 0 to 6 volume% is further more preferable. . If the PVC is within the above range, the ratio of the discontinuous phase of the pigment in the coating film increases, and the ratio of the resin or the like that forms the continuous phase increases. Volume change due to swelling of the hydrophilic polymer in the deep part of the film and hydrolysis of the hydrolyzable polymer (A) are suppressed, and as a result, the coating state is improved. Furthermore, since the rapid loss of the hydrophilic polymer (B) to the outside of the coating film is suppressed, the frictional resistance reduction 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 PVC in the solid content of the coating is 0% by volume.

In addition, PVC of a coating composition or a coating film says the value measured with the following method.
After thoroughly stirring 10 g of the coating composition measured in the settling tube together with about 50 mL of the organic solvent contained in the coating composition, the mixture is separated at 3500 rpm for 30 minutes using a centrifuge, and the supernatant is taken out. After repeating this operation three times, the residue in the precipitation tube was dried at 125 ° C. for 1 hour using a hot air dryer, and the mass was measured. Based on the mass value and the specific gravity measured using a true hydrometer. To calculate the residual volume V1. Subsequently, the volume V2 of the solid content of the paint in 10 g of the paint composition is measured, and calculated as PVC = V1 / V2 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 evaluated, the measurement is performed 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 further preferably 20% by mass or less in the solid content of the coating composition. It is. The lower limit of the content of the pigment (C) when the coating composition of the present invention contains the pigment (C) is not particularly limited, but is preferably 0.01% by mass or more in the solid content of the coating composition.

<Optional component>
In addition to the hydrolyzable polymer (A), the hydrophilic polymer (B), and the pigment (C), the coating composition for forming a frictional resistance-reducing coating film according to the present invention includes an organic solvent (if necessary). D), organic antifouling agent (E), monocarboxylic acid compound (F), anti-sagging-precipitating agent (G), plasticizer (H), dehydrating agent (I) and the like may be contained.

[Organic solvent (D)]
In the present invention, an 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), aromatic hydrocarbon type, aliphatic hydrocarbon type, alicyclic hydrocarbon type, ketone type, ester type, alcohol type organic solvent can be used, preferably aromatic type carbonization. It is a hydrogen-based organic solvent.
Examples of the aromatic hydrocarbon-based organic solvent include toluene, xylene, styrene, mesitylene and the like.
Examples of the aliphatic hydrocarbon organic solvent include pentane, hexane, heptane, and octane.
Examples of the alicyclic hydrocarbon-based organic solvent include cyclohexane, methylcyclohexane, and ethylcyclohexane.
Examples of the ketone organic solvent include acetylacetone, acetone, methyl ethyl ketone, methyl isobutyl ketone, and dimethyl carbonate.
Examples of the ester organic solvent include propylene glycol monomethyl ether acetate.
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 an organic solvent (D), the preferred amount of the organic solvent (D) in the coating composition is determined by the desired viscosity according to the coating form of the coating composition. However, usually 0.001 to 50 mass% is preferable. When there is too much content of an organic solvent (D), malfunctions, such as a fall of sagging stop property, may generate | occur | produce.

[Organic antifouling agent (E)]
In the present invention, an organic antifouling agent (E) may be used for the purpose of improving the biofouling resistance of the coating film.
Examples of the organic antifouling agent (E) include 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile (abbreviation: tralopyryl), 4,5- Dichloro-2-n-octyl-4-isothiazolin-3-one (abbreviation: DCOIT), borane-nitrogen base adduct (pyridine triphenylborane, 4-isopropylpyridinediphenylmethylborane, etc.), (+/-)- 4- [1- (2,3-dimethylphenyl) ethyl] -1H-imidazole (abbreviation: medetomidine), N, N-dimethyl-N ′-(3,4-dichlorophenyl) urea, N- (2,4, 6-trichlorophenyl) maleimide, 2-methylthio-4-tert-butylamino-6-cyclopropylamino-1,3,5-triazine, 2,4,5 , 6-tetrachloroisophthalonitrile, bisdimethyldithiocarbamoyl zinc ethylene bisdithiocarbamate, chloromethyl-n-octyl disulfide, N, N-dimethyl-N′-phenyl- (N′-fluorodichloromethylthio) sulfamide, tetraalkyl Thiuram disulfide, zinc dimethyldithiocarbamate, zinc ethylenebisdithiocarbamate, 2,3-dichloro-N- (2 ', 6'-diethylphenyl) maleimide, and 2,3-dichloro-N- (2'-ethyl-6) '-Methylphenyl) maleimide. Of these, DCOIT, tralopyril, 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 an organic antifouling agent (E), the content of the organic antifouling agent (E) in the coating composition is usually preferably 0.05 to 20% by mass, preferably 0.1 -5 mass% is more preferable. 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 coating film properties.

[Monocarboxylic acid compound (F)]
In the present invention, a monocarboxylic acid compound (F) may be used for the purpose of improving the surface renewability and water resistance of the coating film.
Examples of the monocarboxylic acid compound (F) include a compound in which a carboxy group is substituted for a saturated or unsaturated aliphatic hydrocarbon group having 10 to 40 carbon atoms, or a saturated or unsaturated group having 3 to 40 carbon atoms. A compound in which one carboxy group is substituted on a saturated alicyclic hydrocarbon group, or a compound in which one carboxy group is substituted on these substituents is preferable.
Among them, trimethylisobutenylcyclohexene carboxylic acid compound, versatic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, abietic acid, neoabietic acid, pimaric acid, dehydroabietic acid, 12-hydroxystearic acid, naphthene Acids and their metal salts are preferred. Also preferred are rosins based on rosin acids such as abietic acid, parastrinic acid and isopimaric acid.
Examples of trimethylisobutenylcyclohexenecarboxylic acid include a reaction product of 2,6-dimethylocta-2,4,6-triene and methacrylic acid, which is 1,2,3-trimethyl-5- (2-Methylprop-1-en-1-yl) cyclohex-3-en-1-carboxylic acid and 1,4,5-trimethyl-2- (2-methylprop-1-en-1-yl) cyclohexa- The main component (85% by mass or more) is 3-ene-1-carboxylic acid.
When the coating composition of the present invention contains a monocarboxylic acid compound (F), the content of the monocarboxylic acid compound (F) in the coating composition is preferably 0.1 to 50% by mass.

[Sagging Stopper-Antisettling Agent (G)]
In the present invention, a sagging-preventing agent (G) may be used for the purpose of adjusting the viscosity of the coating composition. Anti-sagging-anti-settling agent (G) includes organic clay waxes (such as Al, Ca, Zn stearate salts, lecithin salts, alkyl sulfonates), organic waxes (polyethylene wax, polyethylene oxide wax, amide wax). , Polyamide wax, hydrogenated castor oil wax, etc.), mixtures of organic clay wax and organic wax, synthetic fine powder silica, and the like.
Commercially available products may be used as the anti-sagging agent (G), such as “DISPARON 305”, “DISPARON 4200-20” and “DISPARON A630-20X” manufactured by Enomoto Kasei Co., Ltd. It is done.
When the coating composition of the present invention contains the anti-sagging agent (G), the content of the anti-sagging agent (G) in the coating composition is usually preferably 0.01 to 10% by mass. 0.1 to 3% by mass is more preferable.

[Plasticizer (H)]
The coating composition of the present invention may use a plasticizer (H) for the purpose of improving the 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), and polyvinyl ethyl ether. Among these, 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.
Commercially available products may be used as the plasticizer (H), for example, “n-paraffin” manufactured by Nippon Petrochemical Co., Ltd. as the n-paraffin, and manufactured by East Tohoku Chemical Co., Ltd. as the chlorinated paraffin. "Toyoparax A-40 / A-50 / A-70 / A-145 / A-150" etc. can be mentioned.
When the coating composition of this invention contains a plasticizer (H), as for content of the plasticizer (H) in a coating composition, 0.1-10 mass% is preferable.

[(I) Dehydrating agent]
In the present invention, the 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 alkoxysilanes, zeolites known by the general name of “molecular sieve”, orthoesters such as alumina and alkyl orthoformate, orthoboric acid, and isocyanates. These dehydrating agents may be used alone or in combination of two or more.
When the coating composition of the present invention contains a dehydrating agent (I), the content of the dehydrating agent (I) in the coating composition is preferably 0.1 to 10% by mass, and 0.2 to 2% by mass. More preferred. When the content of the dehydrating agent (I) is within the above range, the storage stability of the coating composition can be kept good, and the occurrence of coating abnormality such as secondary aggregation of the hydrophilic polymer (B) is suppressed. be able to.

<Method for producing a coating composition for forming a frictional resistance-reducing coating film>
The coating composition of the present invention can be prepared using the same apparatus, means, and the like as a known general antifouling coating. Specifically, the solution of the hydrolyzable polymer (A) prepared in advance and a solution or dispersion obtained by mixing other additives as necessary are stirred, while the hydrophilicity is increased. It can be prepared by adding the molecule (B) and further stirring and mixing.

[Friction resistance-reducing coating film and substrate with the coating film]
The coating composition of the present invention is used to form a frictional resistance reducing coating film. That is, the frictional resistance reducing coating film of the present invention is obtained by curing the coating composition of the present invention. Specifically, for example, after the coating composition of the present invention is applied to a substrate or the like, a frictional resistance-reduced coating film can be obtained by drying.
Examples of the method for 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-described method can be cured, for example, by leaving it at 25 ° C. for about 0.5 to 14 days to obtain a coating film. The coating composition may be cured while blowing air under heating.
The thickness after curing of the frictional resistance reduced coating film is preferably about 30 to 1,000 μm from the viewpoint of improving the coating film strength and reducing the frictional resistance, for example. As a method for producing a frictional resistance-reducing coating film having this thickness, there is a method in which the coating composition is applied at a thickness of usually 10 to 300 μm, preferably 30 to 200 μm per application, once to a plurality of times. It is done.

The base material with a coating film of the present invention has the frictional resistance-reducing coating film on the base material.
The substrate with a coating film of the present invention comprises, for example, a step of obtaining an applied body or an impregnated body by applying or impregnating the coating composition to the substrate, and a coating composition applied or impregnated on the substrate by the step. It can be produced by a method comprising a step of curing, or a method comprising a step of affixing a coating film obtained by curing a coating composition on 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 to the substrate by spraying or other means. It is done.
On the other hand, the method of curing the coating composition applied to or impregnated on the substrate is preferably a method of curing the coating composition by drying the coated body or the impregnated body. The method of drying an application body or an impregnated body by leaving for about 0.5-14 days or forcedly blowing while heating is mentioned. By such a method, the base material with a coating film of the present invention having the frictional resistance-reducing coating film on the base material can be easily produced.

  As a method for sticking a coating film obtained by curing a coating composition to a substrate, for example, a coating obtained by curing the coating composition using a known technique described in JP2013-129724A or the like. The method of sticking the film containing a film | membrane to a base material is mentioned. By this method, a substrate with a coating film in which the substrate is coated with a frictional resistance-reducing coating film can be produced.

  The coating composition of the present invention has a long-term function of reducing the frictional resistance of a substrate in a wide range of industrial fields such as ships, fisheries, pipelines, water facilities, diving equipment, underwater propulsion bodies, power generation, harbors and civil engineering construction. Can be used to maintain the Such base materials include, for example, ships (container ships, large steel ships such as tankers, fishing boats, FRP ships, wooden ships, yachts, etc. hull outer plates, new ships or repair ships), fishing materials (ropes, fishing nets) , Fishing gear, floats, buoys, etc.), oil pipelines, water conduits, circulating water pipes, diver suits, underwater glasses, oxygen cylinders, swimsuits, torpedoes, underwater structures such as water and water outlets of thermal and nuclear power plants, seawater Examples include equipment used (seawater pumps, etc.), mega floats, gulf roads, submarine tunnels, harbor facilities, sludge diffusion prevention membranes for various civil engineering works such as canals and waterways. Among these, as a base material, a ship is preferable.

You may apply | coat or impregnate the coating composition of this invention directly to a base material. The coating composition according to the present invention is also applied to a base material whose material is fiber reinforced plastic (FRP), steel, wood, aluminum alloy, etc. It can adjust so that the adhesiveness to the surface of these base materials (raw materials) may become favorable.
Moreover, the base material to which the coating composition of the present invention is applied may have a coating film already formed on the surface. That is, the coating composition of the present invention may be applied to the surface of a base material on which a base material (undercoat) such as a rust preventive agent or a primer has been previously applied. Furthermore, the coating composition of the present invention may be overcoated on the surface of a base material that has already been coated with a conventional coating or coated with the coating composition of the present invention. The kind of coating film with which the coating composition according to the present invention is in direct contact is not particularly limited.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
The “solid content” of each component used in the examples refers to a component excluding volatile components contained in each component as a solvent, and is obtained by drying each component in a hot air dryer at 125 ° C. for 1 hour. It is regarded as a thing.

<Production of hydrolyzable polymer (A)>
[Preparation Example 1: Preparation of hydrolyzable group-containing monomer (a0)]
In producing the hydrolyzable polymer (A), first, a hydrolyzable group-containing monomer (a0) was prepared as follows.
A four-necked flask equipped with a cooler, thermometer, dropping funnel and stirrer was charged with 85.4 parts by mass of propylene glycol monomethyl ether (PGM) and 40.7 parts by mass of zinc oxide, and the temperature was raised to 75 ° C. while stirring. did. Subsequently, a mixture consisting of 43.1 parts by weight of methacrylic acid (MAA), 36.1 parts by weight of acrylic acid (AA), and 5.0 parts by weight of water was dropped from the dropping funnel over a period of 3 hours. 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 hydrolyzable group-containing monomer (a0). The solid content of the reaction solution was 44.8% by mass.

[Production Example 1: Production of hydrolyzable polymer (copolymer containing metal ester group) solution (A1)]
A four-necked flask equipped with a cooler, thermometer, dropping funnel and stirrer was charged with 15.0 parts by mass of propylene glycol monomethyl ether (PGM) and 57.0 parts by mass of xylene and heated to 100 ° C. while stirring. . Subsequently, 52.0 parts by mass of the reaction solution 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). Parts, 2-methoxyethyl acrylate (2-MEA) 5.4 parts by mass, azobisisobutyronitrile (AIBN) (manufactured by Nippon Hydrazine Industry Co., Ltd.) 2.5 parts by mass, azobismethylbutyronitrile (AMBN) ) (Nippon Hydrazine Kogyo Co., Ltd.) 7.0 parts by mass, α-methylstyrene dimer (Nippon Oil & Fats Co., Ltd. “NOFMER MSD”) 1.0 part by mass and xylene 10.0 parts by mass The mixture was added dropwise from the dropping funnel over a period of 6 hours. After completion of dropping, 0.5 parts by mass of t-butyl peroctoate (TBPO) and 7.0 parts by mass of xylene were added dropwise over 30 minutes, and the mixture was further stirred for 1 hour 30 minutes, and then 4.4 parts by mass of xylene was added. Thus, a hydrolyzable polymer solution (A1) which was free of insoluble matter including a hydrolyzable polymer (metal ester group-containing copolymer) and was light yellow and transparent was obtained. The characteristic values of the resulting hydrolyzable polymer solution (A1) are shown in Table 1.

[Production Example 2: Production of hydrolyzable polymer (metal ester group-containing copolymer) solution (A2)]
The monomer charge of Production Example 1 is 48.3 parts by mass of the reaction solution of hydrolyzable group-containing monomer (a0), 12.2 parts by mass of methyl methacrylate (MMA), 62.0 parts by mass of ethyl acrylate (EA). The hydrolyzable polymer (metal ester) is produced in the same manner as in Production Example 1 except that the hydrolyzable polymer (metal ester group-containing copolymer) has no insoluble matter and is light yellow and transparent. Group-containing copolymer) solution (A2) was obtained. The characteristic values of the resulting hydrolyzable polymer solution (A2) are shown in Table 1.

In addition, the measuring method of the Gardner viscosity of the obtained hydrolysable polymer solutions (A1) and (A2) and a weight average molecular weight (Mw) is as follows.
<Gardner viscosity measurement conditions>
The Gardner viscosity was measured at a resin concentration of 35% by mass and 25 ° C. according to JIS K7233 4.3 as described in JP-A-2003-55890.

<Measurement of weight average molecular weight (Mw) of hydrolyzable polymer (A)>
The weight average molecular weight (Mw) of the hydrolyzable polymer (A) was measured using GPC (gel permeation chromatography) under the following conditions.
Apparatus: “HLC-8320GPC” (manufactured by Tosoh Corporation)
Column: Two “TSKgel SuperAWM-H” and one “TSKgel SuperAW2500” are connected (both 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 bath temperature: 40 ° C
Standard substance: Polystyrene Sample preparation method: After adding a small amount of calcium chloride to the polymer solutions (A1) and (A2) prepared in the respective production examples to dehydrate them, the filtrate obtained by filtering with a membrane filter is obtained. A GPC measurement sample was used.

<Manufacture of coating composition>
-Compounding component Each compounding component used for the coating composition is shown in Table 2 and Table 3, and the characteristic of a hydrophilic polymer (B), etc. are shown in Table 4.

* 1: The average molecular weight was measured by GPC-MALS. For separation, “OHpak SB-806HQ” manufactured by Showa Denko KK was used.
“RID20A” manufactured by Shimadzu Corporation was used as the suggested refractive index detector, and “DAWN HELEOS II” manufactured by Wyatt Technology was used as the light scattering detector.
As an eluent, a 50 mM sodium nitrate aqueous solution was used, the flow rate was 0.8 mL / min, and the column temperature was 40 ° C.
* 2: The pretreatment was performed by jet mill pulverization and classification with an aperture of 38 microns.
* 3: The average particle diameter is a 50% diameter (median diameter) measured by a dry method using “SALD-2200” manufactured by Shimadzu Corporation.

[Examples 1-14 and Comparative Examples 1-2]
-Manufacture of coating composition By the mixing | blending (mass part) described in Table 5 and Table 6, each mixing | blending component was mixed and stirred and the coating composition was obtained. In addition, the compounding quantity of each component described in Table 5 and Table 6 has shown the compounding quantity in solid.
Content (mass%) of hydrolyzable polymer (A), hydrophilic polymer (B) in paint solids (coating film) of each paint composition obtained, and pigment volume concentration in paint solids (PVC) is shown together in Tables 5 and 6.

[Evaluation of film durability]
Using a film applicator having a gap of 0.7 mm so that the dry film thickness is 100 μm, the coating compositions of Examples and Comparative Examples described in Table 5 and Table 6 are used on a PVC plate (length 50 mm × width 50 mm). And painted at room temperature. After 1 day at room temperature, the test plate with the coating film was subjected to rotational immersion for 7 days in seawater whose temperature was adjusted to 23 ° C. under a speed condition corresponding to a calculation of approximately 10 knots. After drying for one day, the cut reaching the substrate was made to cross vertically using a cutter knife, and the coating film around the cut part was observed to give the following scores.
〔Evaluation criteria〕
Two points Neither coating collapse nor peeling occurred at any point.
1 point The coating film collapsed or peeled off around the cloth part.
0 point The coating film disintegrated from around the cut part.

[Friction resistance evaluation]
An epoxy anticorrosive paint (trade name: Vanno 500N, manufactured by China Paint Co., Ltd.) is applied as an undercoat on the outer surface of a 310 mm diameter PVC cylinder and dried to obtain a film thickness of 100 μm. The coating compositions of Examples and Comparative Examples described in Table 5 and Table 6 were applied at room temperature using a spray coater so that the dry film thickness was 100 μm. After 1 day at room temperature, the test cylinder with the coating film was immersed in a seawater adjusted to a temperature of 23 ° C. for 7 days under a speed condition in which the water flow velocity on the test coating film was approximately equivalent to 10 knots. Friction resistance evaluation was performed.
The frictional resistance of the coating film was evaluated using a double cylindrical resistance measuring device. The double-cylinder resistance measuring device consists of two cylinders, an inner cylinder and an outer cylinder filled with artificial seawater. An inner cylinder with the coating film of the sample to be measured formed on the outer surface is installed, and the outer cylinder is rotated. Thus, the torque stress applied to the inner cylinder when the rotating water flow is generated is measured.
Using the test cylinder with a coating film of Examples and Comparative Examples prepared above as this inner cylinder, the measured torque stress was compared with the reference torque stress obtained using the uncoated inner cylinder, and the reduction ratio was determined as the friction resistance. It is shown in Table 5 and Table 6 in the reduction rate%. The larger the frictional resistance reduction rate%, the higher the frictional resistance reducing effect by the coating film.
The measurement was carried out at a temperature of 23 ° C. under a speed condition in which the rotational speed of the outer cylinder was set to 400 rpm and the water flow speed on the test coating film was approximately equivalent to 10 knots.

  As is clear from the results of Examples and Comparative Examples, according to the present invention, the frictional resistance-reducing coating film formation that can sufficiently maintain the physical properties of the coating film and the frictional resistance reduction effect over a long period of time in water. It is possible to provide a coating composition for coating, a coating film for reducing frictional resistance obtained by curing the coating composition, and a substrate with a coating film having the coating composition on the substrate.

  The coating composition of the present invention can form a frictional resistance-reducing coating film on the surface of a structure that propels water in a ship or the like, the surface of a structure or the like disposed in the water, and the inner surface of a pipe structure such as a pipeline. In addition, the physical properties of the coating film and the effect of reducing the frictional resistance can be sufficiently maintained over a long period of time in water.

Claims (10)

Containing hydrolyzable polymer (A) and the weight average molecular weight of 500,000 or more hydrophilic polymer (B), the pigment volume concentration to total solid content (PVC) is Ri der less than 20% by volume, Content of the said hydrolyzable polymer (A) in paint solid content is 50-98 mass%, and this hydrophilic polymer (B) originates in 1 type of hydrophilic group containing unsaturated monomer A coating composition for forming a frictional resistance-reducing coating film, which is a homopolymer having a structural unit or a copolymer having a structural unit derived from two or more hydrophilic group-containing unsaturated monomers . The content of the hydrophilic polymer in the paint solids (B) is 1 to 45 wt%, the coating composition of claim 1. The coating composition according to claim 1 or 2 , wherein the hydrolyzable polymer (A) has a metal ester group. The coating composition according to claim 3 , wherein the metal ester group is a divalent metal ester group represented by the following formula (I).

(In the formula, M represents a metal, and * represents that it is linked to an arbitrary organic group.) 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 The coating composition according to any one of claims 1 to 4 . The coating composition according to any one of claims 1 to 5 , wherein the hydrophilic polymer (B) has a weight average molecular weight (Mw) of 3,000,000 or more. A frictional resistance-reducing coating film obtained by curing the coating composition according to any one of claims 1 to 6 . The base material with a coating film which has a frictional resistance reduction coating film of Claim 7 on a base material. The base material with a coating film of Claim 8 whose said base material is a ship. By applying or impregnating the coating composition according to any one of claims 1 to 6 to a substrate, a step (1) of obtaining an applied body or an impregnated body, and drying the applied body or the impregnated body, The manufacturing method of the base material with a frictional resistance reduction coating film which has the process (2) which hardens the said coating composition.