JP2019178329A - Coating material containing friction reducing agent, and friction reducing method using coating material - Google Patents

Abstract

Provided are a friction reducing agent, a paint containing the friction reducing agent, and a friction reducing method using the friction reducing agent, which can greatly reduce the frictional resistance of an aqueous liquid. A paint containing a friction reducing agent comprising a water-soluble polymer compound having an ammonium salt structure in a side chain. The water-soluble polymer compound preferably has a repeating unit represented by the following general formula (1). (R1 is H or methyl group; A is O or NH group; R2 is an alkylene group or an arylene group; R3 to R5 are each independently an alkyl group or an aryl group; X1- is a monovalent anion) Selection diagram] None

Description

  The present invention relates to a paint containing a friction reducing agent, and a friction reducing method using the paint.

Ships receive frictional resistance from seawater during navigation. Moreover, in piping of plants and the like, the liquid flowing through the piping receives frictional resistance from the inner wall of the piping. On the other hand, when a small amount of a polymer compound is added to a liquid, the Toms effect is known as a phenomenon in which the frictional resistance generated between the liquid and the solid is remarkably reduced.
Then, in order to reduce the frictional resistance which a ship receives from seawater, it is examined to paint the surface of a ship bottom using the Toms effect. For example, water-soluble polymer compounds such as polyethylene oxide are known as polymer compounds having the Toms effect, and Patent Documents 1 to 3 disclose a technique for blending a water-soluble polymer compound such as polyethylene oxide into a paint. It is disclosed. Patent Document 4 describes a paint using a specific alkali-soluble resin.

Japanese Patent Laid-Open No. 11-343427 JP 2001-342432 A JP 2012-7048 A JP 2014-162912 A

However, as a result of studies by the present inventors, it has been found that the polymer compound described in the above-mentioned patent document does not have a sufficient friction reducing effect.
An object of the present invention is to provide a friction reducing agent capable of greatly reducing the frictional resistance of an aqueous liquid such as water, seawater, and various aqueous solutions, a paint containing the friction reducing agent, and a friction reducing method using the friction reducing agent. Is to provide.

（式（１）中、Ｒ_１は水素原子またはメチル基を示し、Ａは酸素原子またはＮＨ基を示し、Ｒ_２はアルキレン基またはアリーレン基を示し、Ｒ_３〜Ｒ_５はそれぞれ独立してアルキル基またはアリール基を示し、Ｘ_１ ⁻は１価の陰イオンを示す。）

（式（２）中、Ｘ_２ ⁻は１価の陰イオンを示す。）
［３］［１］または［２］の摩擦低減剤を含有する塗料。
［４］船底塗料である、［３］の塗料。
［５］［１］または［２］の摩擦低減剤を用いた摩擦低減方法。 The present invention has the following aspects.
[1] A friction reducing agent comprising a water-soluble polymer compound having an ammonium salt structure in the side chain. [2] The friction reducing agent according to [1], wherein the water-soluble polymer compound has a repeating unit represented by the following general formula (1) or (2).

(In Formula (1), R ₁ represents a hydrogen atom or a methyl group, A represents an oxygen atom or an NH group, R ₂ represents an alkylene group or an arylene group, and R _{3 to} R ₅ are each independently alkyl. It represents a group or an aryl group, X ₁ ^- represents a monovalent anion).

(In formula (2), X ₂ ⁻ represents a monovalent anion.)
[3] A paint containing the friction reducing agent according to [1] or [2].
[4] The paint according to [3], which is a ship bottom paint.
[5] A friction reducing method using the friction reducing agent according to [1] or [2].

  According to the present invention, a friction reducing agent capable of greatly reducing the frictional resistance of an aqueous liquid such as water, seawater, various aqueous solutions, a paint containing the friction reducing agent, and a friction reducing method using the friction reducing agent. Can be provided.

It is the graph which plotted resistance reduction rate DR [%] (vertical axis) with respect to Reynolds number Re [-] (horizontal axis) about each of Example 1, Example 2, Comparative example 1, and Comparative example 2. FIG. It is the graph which plotted resistance reduction rate DR [%] (vertical axis) versus Reynolds number Re [-] (horizontal axis) about each of Example 1, Example 3, and Example 4.

Hereinafter, the present invention will be described in detail.
The friction reducing agent of the present invention is used for reducing frictional resistance generated between an aqueous liquid such as water, seawater, various aqueous solutions and the solid surface, and has an ammonium salt structure in a side chain. It consists of a water-soluble polymer compound. By using the friction reducing agent, the liquid flow can be converted from a turbulent flow to a laminar flow, thereby greatly reducing the frictional resistance.
The friction reducing agent of the present invention is used in a mode where it is added to a paint for coating a solid surface in contact with an aqueous liquid, such as the surface of the bottom of a hull, the surface of an inner wall of a pipe of a plant, etc. .

  Examples of the water-soluble polymer compound having an ammonium salt structure in the side chain include compounds having a repeating unit represented by the following general formula (1) or (2).

（式（１）中、Ｒ_１は水素原子またはメチル基を示し、Ａは酸素原子またはＮＨ基を示し、Ｒ_２はアルキレン基またはアリーレン基を示し、Ｒ_３〜Ｒ_５はそれぞれ独立してアルキル基またはアリール基を示し、Ｘ_１ ⁻は１価の陰イオンを示す。）

(In Formula (1), R ₁ represents a hydrogen atom or a methyl group, A represents an oxygen atom or an NH group, R ₂ represents an alkylene group or an arylene group, and R _{3 to} R ₅ are each independently alkyl. It represents a group or an aryl group, X ₁ ^- represents a monovalent anion).

（式（２）中、Ｘ_２ ⁻は１価の陰イオンを示す。）

(In formula (2), X ₂ ⁻ represents a monovalent anion.)

R ₁ in the formula (1) is a hydrogen atom or a methyl group, and A represents an oxygen atom or an NH group (—NH—).
R ₂ is an alkylene group or an arylene group. The alkylene group preferably has 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, and a decylene group. However, it may be branched. Examples of the arylene group include a phenylene group, a naphthylene group, and a benzylene group, and these may have a substituent.
R _{3 to} R ₅ are each independently an alkyl group or an aryl group. The alkyl group preferably has 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, cyclopentyl, neopentyl. Group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1,2-dimethylpropyl group, n-hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group Group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group and the like. As an aryl group, a phenyl group, a naphthyl group, a benzyl group etc. are mentioned, for example, These may have a substituent. R _{3 to} R ₅ may be the same as or different from each other. Moreover, R < ₃ > -R < ₅ > may form one ring structure with two of R < ₃ > -R < ₅ >.
X ₁ ⁻ and X ₂ ⁻ in the formulas (1) and (2) each represent a monovalent anion. Examples of the monovalent anion include halide ions such as F ⁻ , Cl ⁻ , Br ⁻ and I ⁻ , C ₂ H ₅ OSO ₃ ⁻ , CH ₃ OSO ₃ ⁻ and ClO ⁻ . Of these, Cl ⁻ is preferable from the viewpoint of ease of synthesis.

The mass average molecular weight of the water-soluble polymer compound is preferably 1,000,000 to 20,000,000, more preferably 1,500,000 to 10,000,000, and 2,000,000 to 4,000,000. 000 is particularly preferred. If the mass average molecular weight is at least the lower limit of the above range, the effect of reducing the friction of the aqueous liquid can be sufficiently obtained. If the mass average molecular weight is not more than the upper limit of the above range, solubility in water can be ensured.
In the present specification, the mass average molecular weight is a value in terms of pullulan (polysaccharide) measured by gel permeation chromatography.

  Among the water-soluble polymer compounds represented by the formulas (1) and (2), they are particularly excellent in the effect of reducing the friction of aqueous liquids. A water-soluble polymer compound having a repeating unit is preferred.

A water-soluble polymer compound having a repeating unit represented by the general formula (1a) (hereinafter also referred to as compound (1a)) is N, N-dimethylaminoethyl methacrylate benzyl quaternary ammonium chloride (hereinafter referred to as monomer (1a). It is also obtained by polymerizing.
For the polymerization, one or more other monomers (for example, (meth) acrylamide, N-substituted derivatives of (meth) acrylamide, (meth) acrylonitrile, (meth) acrylic acid, etc.) that can be copolymerized with the monomer (1a). ) May be used as needed. Examples of the compound (1a) include a homopolymer of N, N-dimethylaminoethyl methacrylate benzyl quaternary ammonium chloride (hereinafter also referred to as compound (1a-1)).

  Polymerization can be carried out with reference to, for example, JP-A-59-135212 and JP-A-61-221324.

A water-soluble polymer compound having a repeating unit represented by the general formula (2a) (hereinafter also referred to as compound (2a)) was obtained by, for example, copolymerizing N-vinylformamide and acrylonitrile. And a step of forming an amidine ring (5-membered ring) having an ammonium salt structure by adding hydrochloric acid to the copolymer and heating it. The molar ratio of N-vinylformamide and acrylonitrile during polymerization is preferably N-vinylformamide: acrylonitrile = 20: 80 to 80:20, particularly preferably 40:60 to 60:40.
For polymerization, other monomers that can be copolymerized with N-vinylformamide and acrylonitrile (for example, (meth) acrylamide, N-substituted derivatives of (meth) acrylamide, (meth) acrylonitrile, (meth) acrylic acid, etc.) The above may be used as necessary. Examples of the compound (2a) include a binary copolymer of N-vinylformamide and acrylonitrile (hereinafter also referred to as compound (2a-1)) or a derivative thereof.

  The polymerization can be carried out with reference to, for example, JP-A-6-287232, JP-A-09-087323, JP-A-5-192513.

A friction reducing agent comprising a water-soluble polymer compound having an ammonium salt structure in the side chain is added to a paint for coating a solid surface such as the surface of the bottom of a hull or the inner wall of a pipe of a plant, for example. Used in embodiments and the like. The friction reducing agent gradually dissolves into the aqueous liquid from the coating film formed of the paint. Thereby, there exists a friction reduction effect over a long period of time.
The friction reducing agent is preferably added in the range of 1.0 to 10% by mass when the solid content of the coating is 100% by mass.

The paint of the present invention contains an organic polymer compound that does not dissolve in water in addition to a water-soluble polymer compound having an ammonium salt structure in the side chain, and if necessary, a normal paint such as a colorant, filler, solvent, etc. A compounding component can be contained.
As the organic polymer compound, a compound having compatibility with a friction reducing agent and having a coating film-forming ability is preferable, and examples thereof include an acrylic resin, an epoxy resin, and a urethane resin. By using such an organic polymer compound, mechanical strength can be imparted to the coating film, and the elution rate of the friction reducing agent from the coating film can be adjusted.

  Examples of the solvent include water, ketone solvents such as acetone, ester solvents such as ethyl acetate, ether solvents such as tetrahydrofuran, and aromatic solvents such as toluene, which are used for the purpose of adjusting the viscosity of the paint. Most of the solvent is removed from the coating film in the course of drying the coating film.

  An undercoating film may be formed in advance on the solid surface to which the paint of the present invention is applied. Examples of the paint for forming the base coating film include acrylic paints, epoxy paints, urethane paints, and the like.

  As described above, the friction reducing agent of the present invention comprising a water-soluble polymer compound having an ammonium salt structure in the side chain is excellent in the friction reducing effect. Therefore, the friction reducing agent of the present invention is added to a paint for coating a solid surface that comes into contact with an aqueous liquid, such as the surface of the bottom of a hull or the surface of an inner wall of a pipe of a plant or the like. The friction reducing agent of the present invention is particularly suitable for addition to ship bottom paints.

Hereinafter, the present invention will be described specifically by way of examples. Example 2 is a reference example.
[Example 1]
An aqueous solution (1) containing the above compound (1a-1) having a mass average molecular weight of 3,000,000 at a concentration of 100 ppm was prepared. In addition, the viscosity (25 ° C.) of the aqueous solution (1) is measured with a B-type viscometer in advance, and the mass of the aqueous solution (1) weighed in a 50 mL volumetric flask is measured to calculate the density of the aqueous solution (1). I kept it.
On the other hand, the aqueous solution (1) was put into the inner cylinder of the coaxial double cylinder device, the inner cylinder was rotated with a motor, and the torque value applied to the inner cylinder was measured with a torque meter. The rotational speed of the inner cylinder was changed in increments of 100 rpm within a range of 300 to 1000 rpm, and the torque value at each rotational speed was measured.
Based on the following mathematical formula, the measured torque value T [Nm] was dimensionless, and the dimensionless torque G was calculated. Then, by comparing the dimensionless torque G _w of water, it was calculated drag reduction ratio (DR value,%). The Reynolds number was defined as follows.

Each symbol has the following meaning.
Re: Reynolds number [-]
r _i : inner cylinder radius [m]
r ₀ : outer cylinder radius [m]
ω: angular velocity [rad / s]
ν: Kinematic viscosity [m ² / s]
ρ: density of aqueous solution (1) [kg / m ³ ]
L: Height of inner cylinder [m]

[Example 2]
An aqueous solution (2) containing the above compound (2a-1) having a mass average molecular weight of 3,000,000 at a concentration of 100 ppm was prepared. The resistance reduction rate DR [%] was calculated in the same manner as in Example 1 except that the aqueous solution (2) was used.

[Comparative Example 1]
An aqueous solution (3) containing polyethylene oxide having a mass average molecular weight in the range of 3,500,000 to 4,000,000 at a concentration of 100 ppm was prepared. The resistance reduction rate DR [%] was calculated in the same manner as in Example 1 except that the aqueous solution (3) was used.

[Comparative Example 2]
An aqueous solution (4) containing polyacrylamide (mass average molecular weight: 15,000,000) consisting of repeating units represented by the following general formula (α) at a concentration of 100 ppm was prepared. The resistance reduction rate DR [%] was calculated in the same manner as in Example 1 except that the aqueous solution (4) was used.

(Results and Discussion)
FIG. 1 shows a graph in which DR [%] (vertical axis) is plotted against Reynolds number Re (horizontal axis) for each of Example 1, Example 2, Comparative Example 1 and Comparative Example 2.
As shown in FIG. 1, in Example 1 and Example 2, a large DR [%] was obtained in a turbulent flow region having a Reynolds number Re of several thousand or more.
On the other hand, in Comparative Example 1 and Comparative Example 2, a large DR [%] was not obtained.
When the Reynolds number Re exceeds 2300, the liquid is said to be turbulent. The fact that the friction reducing effect is recognized in the region where the Reynolds number Re is several thousand or more means that the turbulent flow can be laminarized, and has great technical significance.
From the above results, it was clarified that the water-soluble polymer compound having an ammonium salt structure in the side chain has a friction reducing effect and has excellent performance as a friction reducing agent.

[Examples 3 and 4]
An aqueous solution (5) (Example 3) containing the compound (1a-1) used in Example 1 at a concentration of 50 ppm and an aqueous solution (6) (Example 4) containing a concentration of 10 ppm were prepared. Using each of the aqueous solutions, the resistance reduction rate DR [%] was calculated in the same manner as in Example 1.

(Results and Discussion)
FIG. 2 shows a graph in which DR [%] (vertical axis) is plotted against Reynolds number Re (horizontal axis) for each of Example 1, Example 3 and Example 4.
As shown in FIG. 2, when the concentration of the compound (1a-1) is 50 ppm (Example 3) and 10 ppm (Example 4), the friction reducing effect is obtained although the concentration is smaller than that when the concentration is 100 ppm. I understood.

  The friction reducing agent of the present invention can greatly reduce the frictional resistance of aqueous liquids such as water, seawater and various aqueous solutions. Therefore, by adding the friction reducing agent of the present invention to a paint for coating a solid surface in contact with an aqueous liquid, such as the surface of the bottom of a hull or the inner wall of a pipe of a plant or the like, Energy loss when the liquid flows through the pipe can be greatly reduced.

Claims (3)

The coating material containing the friction reducing agent which consists of a water-soluble polymer compound which has a repeating unit represented by following General formula (1).

(In Formula (1), R ₁ represents a hydrogen atom or a methyl group, A represents an oxygen atom or an NH group, R ₂ represents an alkylene group or an arylene group, and R _{3 to} R ₅ are each independently alkyl. It represents a group or an aryl group, X ₁ ^- represents a monovalent anion).   The paint according to claim 1, which is a ship bottom paint.   A friction reducing method using the paint according to claim 1.

Images