JP6087649B2 - Paints and painted articles - Google Patents

Description

  The present invention relates to a coating material containing sodium silicate and lithium silicate, and a coated article obtained by coating the coating material with the coating material.

Since metal materials such as steel materials are oxidized and corroded by oxygen and moisture in the atmosphere, it is necessary to coat and protect the surfaces by applying various types of plating or coating materials.
Examples of the paint include paints containing zinc and aluminum as metal pigments. Since zinc and aluminum have a higher ionization tendency than iron, they elute prior to iron, and an effect of suppressing corrosion of iron (sacrificial anticorrosive action) is obtained.

Patent Document 1 discloses that after coating an object to be coated with an alkyl silicate-based high-concentration zinc powder coating containing zinc dust, an alkyl silicate, and a solvent such as ethylene glycol monoethyl ether having a boiling point of 156 ° C., the coating film is made into a base. An invention of a coating film curing method for treating with an aqueous substance-containing aqueous liquid is disclosed. According to the present invention, the hydrolysis and dehydration condensation reaction of the alkyl silicate is promoted by the basic substance-containing aqueous liquid, and the curing of the coating film is promoted.
In Patent Document 2, an alkyl silicate, an alcohol containing isobutyl alcohol having a boiling point of 108 ° C., water, and a solution containing hydrochloric acid are reacted to prepare an alkyl silicate hydrolysis initial condensate, and then zinc dust is added to the anticorrosion paint. And an anticorrosion coating method for applying the anticorrosion paint on the surface of a steel material as a primer is disclosed.
Patent Document 3 discloses an invention of a rust-preventing primer which contains a partially hydrolyzed and condensed alkyl silicate, zinc powder, and a thickener.
Patent Document 4 discloses an invention of a water-diluted coating composition containing a high-boiling organic liquid having a boiling point exceeding about 100 ° C. at atmospheric pressure, a particulate metal, a thickener, and a silane binder. That is, it is disclosed that water that hydrolyzes a silane binder is blended with an alkylsilicate-based zinc powder paint.

Patent Document 5 discloses an invention of a coating material made of zinc or a zinc-based alloy such as Zn-10% Al-0.1% Mg containing zinc as a main component and containing a flake-like metal powder and a liquid medium. Has been. According to the present invention, the metal powder is flaked to increase the specific surface area, so that the contact between the metal powders becomes close, and in addition to the active anticorrosive property of the metal itself, the protective barrier based on the flake shape An effect (passive anticorrosion) is also obtained, the content of the metal powder can be reduced, and the occurrence of cracks in the coating film can be suppressed.
Patent Document 6 discloses an invention of a metal powder made of an alloy of zinc and aluminum and used for mechanical plating. Rust prevention is improved by alloying aluminum with zinc, but the adhesion of the coating film is worse than with zinc alone. According to this invention, by setting the zinc content in the alloy to about 50% by mass or more, it is possible to have both good rust prevention and adhesion of the coating film.
In Patent Document 7, as in the inventions of Patent Documents 5 and 6, a metal powder made of an alloy of zinc and a non-zinc metal containing 50% by mass or more of zinc and having a flake shape as in the invention of Patent Document 5 The invention of the coating material which has favorable rust prevention property is disclosed by using this with a liquid medium.

  Patent Document 8 contains about 20 to 70% by mass of water, a low-boiling organic liquid, a particulate metal, an alkoxy group, and about 3 to 20% by mass of a silane binder (particularly an epoxy functional silane). ), And a wetting agent, and in addition to corrosion resistance, disclosed is an invention of a coating composition having a desired coating tackiness on a workpiece.

Patent Document 9 discloses an alkali metal silicate represented by M ₂ O · nSiO ₂ (wherein M represents sodium and / or potassium, and n represents a number of 2.0 to 4.1). And an aqueous solution of lithium silicate represented by Li ₂ O · mSiO ₂ (wherein m represents a number of 4 to 5). In this invention, when a paint containing sodium silicate was baked at a low temperature, sodium silicate was dissolved in water, and when baked at a high temperature, foam was lost and the coating film was lost. By doing so, the water resistance of the paint is improved.

JP-A-55-108473 JP-A-6-31245 JP-A-7-228801 Japanese Patent No. 3904669 Japanese Patent Laid-Open No. 61-123684 JP-A-55-119101 Japanese Patent No. 4198919 JP 2002-121485 A Japanese Patent Laid-Open No. 7-18202

In the inventions of Patent Documents 5 to 7 described above, good rust prevention is obtained by using a zinc-aluminum alloy instead of the zinc powder of Patent Documents 1 to 4 as the metal powder of the pigment, and the invention of Patent Document 8 In No. 1, good coating adhesiveness is obtained by containing approximately 3 to 20% by mass of a silane binder in the coating composition, but further improvement in rust prevention is required. For example, when 1000 hours have passed in the salt spray test, it is required that red rust is not generated in a coated article in which a coating film is formed on a base material made of steel.
In addition, it is necessary to form a coating film uniformly on the surface of products that are used in combination with parts of dissimilar metals and have complicated shapes, such as bolts, nuts, washers, etc. The metal must be uniformly dispersed.
Furthermore, in patent document 9, although the water resistance of the coating material containing sodium silicate has improved, there existed a problem that rust prevention property was inadequate.

  The present invention has been made in view of such circumstances, and has good water resistance, storage stability, and rust resistance, and a coating material coated with the paint to have good corrosion resistance. The object is to provide painted articles.

As a result of earnest research, the present inventors have developed a paint containing aluminum, sodium silicate, lithium silicate, a silane compound, a surfactant, and water on an object on which a coating film or plating film containing zinc is formed. It has been found that the corrosion resistance is remarkably improved when a coating is formed by coating, and the present invention has been completed.
That is, the paint according to the first invention is a paint applied to a coating film or a plating film containing zinc, and contains aluminum, sodium silicate, lithium silicate, a silane compound, a surfactant, and water. to Ri Na, mass proportion of the effective component of the lithium silicate of the active ingredient of the sodium silicate is characterized der Rukoto 50/50 or 88/12 or less.
Here, the active ingredient of sodium silicate and the active ingredient of lithium silicate refer to respective heating residues.

Coating material according to the second aspect, in the first shot bright, the silane compound, in the molecule, an alkyl group, a haloalkyl group substituted phenyl group, or a part or all of the hydrogen atoms with halogen atoms, hydrolyzable It has a silicon group.

Coating material according to the third invention, the first or second shot Oite bright, the surfactant, polyoxyethylene alkyl amines, polyoxyethylene alkyl ethers, polyoxyethylene distyrenated phenyl ether, polyoxyethylene sorbitan It is at least one selected from the group consisting of fatty acid esters, sorbitan fatty acid esters, and alkyl ether phosphate salts.

The paint according to the fourth invention is characterized in that in any one of the first to third inventions, the paint further contains a mica pigment.

A coated article according to a fifth aspect of the present invention is characterized in that an object to be coated including an iron-based base material has a first coating film formed using the coating material according to the first to fourth aspects of the invention.
Here, the to-be-coated object including the iron-based base material includes those in which the iron-based base material is plated or painted.

A coated article according to a sixth aspect of the present invention includes, in the fifth aspect , a zinc-iron alloy undercoating formed by impact galvanization between the surface of the iron-based base material and the first coating. Features.

A coated article according to a seventh invention is the powdered alloy comprising zinc powder or zinc and aluminum on the surface of the iron-based base material or the zinc-iron alloy undercoat in the fifth or sixth invention. It has the 2nd coating film formed using the undercoat paint which has this.

The coated article according to an eighth aspect of the present invention is the coated article according to the seventh aspect , wherein the undercoat paint comprises at least one functional group selected from the group consisting of an epoxy group, a methacryloxy group, an acryloxy group, an amino group, and a vinyl group in the molecule. A silane coupling agent having a hydrolyzable silicon group and / or a silane compound having a hydrolyzable silicon group and excluding the silane coupling agent in the molecule, and a surfactant. .

Since the paint of the present invention contains lithium silicate in addition to sodium silicate, the water resistance is improved, the film has good storage stability, and the coating film loss during baking is suppressed. And since it contains aluminum that has a higher ionization tendency than zinc, a sacrificial anticorrosive action that suppresses corrosion of zinc is obtained when it is coated on a coating film or plating film containing zinc that is formed on the object to be coated, Coupled with the reaction of sodium silicate with zinc, the anticorrosive property of the coating film or plating film containing zinc is maintained over a long period of time. That is, the sacrificial anticorrosive action of zinc is exhibited over a long period of time. For example, an object to be coated made of an iron-based material has good corrosion resistance over a long period of time.
In addition, since the coating material of the present invention contains a silane compound and a surfactant, the silane compound is easily mixed with water by the surfactant and easily hydrolyzed, and the aluminum is combined with the silanol groups generated by the hydrolysis to form the coating material. The coating is well dispersed and stabilized, and the coating is easily cured when baked, and a coating film can be uniformly formed on the object to be coated.

  According to the present invention, a paint to be coated on a coating film or plating film containing zinc of an object to be coated contains aluminum, sodium silicate, lithium silicate, a silane compound, a surfactant, and water. Therefore, it can have rust prevention and water resistance in good balance, and the rust prevention of the coating film or plating film containing zinc is maintained over a long period of time. Therefore, for example, when the object to be coated includes an iron-based base material, the object to be coated has good corrosion resistance over a long period of time.

1. Topcoat paint The paint according to the present invention (hereinafter referred to as the topcoat paint) is a paint to be applied to a coating film or plating film containing zinc to be coated, and includes aluminum, sodium silicate, lithium silicate, and a silane compound. , Containing a surfactant and water.

It is preferable to use aluminum that has a scaly shape and is prepared in a paste form with an organic solvent.
The top coating composition according to the present invention can contain metals such as zinc and magnesium in addition to aluminum.

  The mass ratio of the active ingredient of sodium silicate to the active ingredient of lithium silicate is preferably 50/50 or more and 88/12 or less. In this case, when baking the coating film coated on the object to be coated at low temperature, it is suppressed that sodium silicate is dissolved in water, foaming is suppressed when baking at high temperature, and loss of the coating film is suppressed, The rust prevention property of the coating film becomes better. The mass ratio is more preferably 60/40 to 86/14, further preferably 72/28 to 86/14, and particularly preferably 74/26 to 86/14.

The silane compound preferably has an alkyl group, a phenyl group, or a haloalkyl group in which some or all of the hydrogen atoms are substituted with a halogen atom and a hydrolyzable silicon group in the molecule.
The hydrolyzable silicon group is not particularly limited, but an alkoxysilyl group is preferable from the viewpoint of handleability, and a methoxysilyl group and an ethoxysilyl group are particularly preferable from the viewpoint of reactivity.
Examples of the silane compound include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane. And trifluoropropyltrimethoxysilane.

This silane compound is easily hydrolyzed to form a silanol group, and the silanol group is bonded to aluminum. Therefore, it is considered that aluminum is well dispersed and stabilized in the paint. At the time of coating film formation, the silanol group also binds to the lower layer coating film, so that the adhesion between the coating films is also improved.
From the viewpoint of expression of this effect and the storage stability of the paint, the mass ratio of the silane compound to aluminum (the active ingredient: the content of aluminum in the aluminum paste when aluminum is prepared in the aluminum paste) Is preferably 0.3 or more and 3 or less, more preferably 0.4 or more and 2 or less.
This silane compound has a silane coupling having in its molecule at least one functional group selected from the group consisting of an epoxy group, a methacryloxy group, an acryloxy group, an amino group, a mercapto group, and a vinyl group and a hydrolyzable silicon group. Unlike the agent, the above-described effects can be achieved even in a solution having a high pH.

  The surfactant is at least selected from the group consisting of polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, and alkyl ether phosphate salt. One type is preferred.

  Polyoxyethylene alkylamine is represented by the general formula of the following formula (1).

However, a = 1, 2, ...
b = 1, 2,
R = C _n H _{2n + 1}
n = 1, 2,

The polyoxyethylene alkyl ether is represented by the general formula of the following formula (2).
_{RO- (CH 2 CH 2 O)} n -H ··· (2)
n = 1, 2,
R = C _m H _{2m + 1}
m = 1, 2,

  Polyoxyethylene distyrenated phenyl ether is represented by the following general formula (3).

  However, n = 1, 2, ...

  The polyoxyethylene sorbitan fatty acid ester is represented by the following general formula (4).

However, a = 1, 2, ...
b = 1, 2,
c = 1, 2,
R = C _n H _{2n + 1}
n = 1, 2,

  Sorbitan fatty acid ester is represented by the following general formula (5).

However, R = C _n H _{2n + 1}
n = 1, 2,

By containing the surfactant, the silane compound is easily adapted to water, the hydrolysis of the silane compound is promoted, and the resulting silanol group is bonded to aluminum.
Although the HLB is considered when determining the type and combination of surfactants, the preferred HLB range varies depending on the type and combination of surfactants, as will be described later, so it corresponds to the type and combination of surfactants. A surfactant with HLB is selected.

  The top coating composition of the present invention preferably further contains a mica pigment. Thereby, the rust prevention property of top coat is further improved. The mass ratio of the mica pigment to the total of the active ingredient of sodium silicate and the active ingredient of lithium silicate is preferably 0.05 or more and 0.7 or less, more preferably 0.2 or more and 0.5 or less. .

The top coating composition of the present invention can be obtained by mixing and stirring each component according to a normal production method. At that time, in addition to the above-described components, paint additives such as a wetting and dispersing agent, a wetting agent, an antifoaming agent, a thickening agent, and a pH adjusting agent may be blended. For example, wetting agents such as polycarboxylic acid-based wet dispersing agents, organic phosphate esters, diester sulfosuccinates such as sodium bistridecyl sulfosuccinate, silicone-based or acrylic-based additives, which are general paint additives An antifoaming agent etc. can be mix | blended.
Examples of thickeners include hydroxyethyl cellulose, methyl cellulose, methyl hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, methyl ethyl cellulose ethers, and mixtures of these substances.

  The top coating composition of the present invention can contain an appropriate amount of water depending on the coating method, the film thickness of the coating film, the baking conditions, and the like. It is preferable to contain the following. In addition to the organic solvent contained in the aluminum paste, an organic liquid can be contained in the paint. For example, an acid such as acetic acid can be used as the organic liquid.

2. Painted article The coated article of the present invention has a first coating film formed on the article to be coated using the above-described topcoat paint. The article to be coated is not particularly limited, and may be a ceramic article or the like, but can be suitably applied to a article including an iron-based base material made of an iron-based material such as steel. The iron-based material may be in the form of an alloy or an intermetallic mixture.
Examples of articles to be coated that include an iron-based base material include all products using iron-based materials such as chains, gears, speed reducers, and linear cylinder bodies or cases. As a chain, a pair of outer plates connected by two pins and a pair of inner plates connected by two bushes are alternately connected with the pins loosely fitted to the bushes. Is mentioned. The paint of the present invention can also be suitably applied to automobile bolts, nuts, washers, pins, screws, and the like that may be exposed to water.

The surface of the object to be coated is preferably cleaned and / or degreased to remove foreign matter before coating. Degreasing can be performed, for example, with hexane or the like. Moreover, you may use the well-known chemical | medical agent containing a metasilicate, caustic soda, carbon tetrachloride, trichloroethylene, etc.
And as a process of the surface of a to-be-coated object, you may decide to perform the shot blast process which spouts a shot (small steel ball) toward this surface with high-pressure air, and touches this surface and finishes the surface.

  The coated article of the present invention is a zinc-iron alloy base formed by impact galvanization between the surface of an iron base material and the first coating film when the article to be coated contains an iron base material. Can have a coating.

  Moreover, the coated article of the present invention has a second coating film formed on the surface of the iron-based base material or the zinc-iron alloy undercoating using a primer coating described later, and the second coating. What formed the 1st coating film on the film | membrane may be used.

3. Undercoat paint The undercoat paint of the present invention comprises zinc powder or a powdered alloy containing zinc and aluminum. The undercoat paint of the present invention may further contain aluminum powder.
The metal powder is preferably flaky. By making it into flakes, the specific surface area increases, the contact between the powders becomes close, and in addition to the active corrosion resistance of the metal itself, a protective barrier effect (passive corrosion resistance) based on the flake shape is also obtained. The content of the alloy can be reduced, and the occurrence of cracks in the coating film can be suppressed.
When the undercoat paint includes an alloy, the alloy can include magnesium, tin, cobalt, manganese, and the like in addition to zinc and aluminum. For example, a zinc-aluminum-magnesium alloy or the like can be used as an alloy of three metals.
From the viewpoint of rust prevention, adhesion to an object to be coated, and cost, zinc is preferably contained in the alloy in an amount of 50% by mass or more, more preferably 80% by mass or more, and further preferably 85% by mass or more.

It is preferable to use an alloy in the form of a paste. Examples of the paste liquid include dipropylene glycol and mineral spirit.
The alloy is preferably contained in the alloy paste at approximately 90 to 95% by mass.
And when an alloy is a zinc-aluminum alloy, it is more preferable that about 85-90 mass% zinc and about 3-8 mass% aluminum are included in an alloy paste, and the remainder is a paste liquid.

  The undercoat paint of the present invention may contain, in addition to the alloy, a single metal (flaked or non-flaked) such as powdered zinc or aluminum. It is preferable to use a single metal that is in the form of a paste.

  The undercoat paint of the present invention is at least one selected from the group consisting of the above-mentioned polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene sorbitan fatty acid ester, and sorbitan fatty acid ester. It is a seed and preferably contains a surfactant having an HLB of 6 or more and 17 or less.

By containing the surfactant, the dispersibility of the alloy in water is improved.
From the viewpoint that this effect is effectively achieved, the mass ratio of the surfactant to the alloy is preferably 0.01 or more and 0.05 or less, and more preferably 0.1 or more and 0.25 or less. Although the HLB is considered when determining the type and combination of surfactants, the preferred HLB range varies depending on the type and combination of surfactants, as will be described later, so it corresponds to the type and combination of surfactants. A surfactant with HLB is selected.

The undercoat paint of the present invention is a silane coupling agent having in the molecule at least one functional group selected from the group consisting of an epoxy group, a methacryloxy group, an acryloxy group, an amino group, and a vinyl group and a hydrolyzable silicon group It is preferable to contain.
The hydrolyzable silicon group is not particularly limited, but an alkoxysilyl group is preferable from the viewpoint of handleability, and a methoxysilyl group and an ethoxysilyl group are particularly preferable from the viewpoint of reactivity.

  As a silane coupling agent, when an epoxy group is included as a functional group, for example, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxy Examples include silane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

  From the viewpoint of improving the coating properties and stabilizing the coating composition, the silane coupling agent preferably has an alkyl group containing an epoxy group as a functional group, particularly an alkyl group containing a glycidoxy group.

The silanol group is generated by hydrolysis of the silane coupling agent, and the silanol group is bonded to the alloy. Therefore, it is considered that the alloy is stabilized in the paint. The silanol group is also bonded to the object to be coated, and the coating component is crosslinked or chemically bonded by the functional group, so that the adhesion of the coating film is improved.
From the viewpoints of good adhesion of the coating film and storage stability of the paint, the mass ratio of the silane coupling agent to the alloy is preferably 0.01 or more and 1.0 or less, more preferably 0.25 or more and 0.00. It is 8 or less, more preferably 0.3 or more and 0.7 or less.

The undercoat paint of the present invention may further contain a silane compound having a hydrolyzable silicon group in the molecule and excluding a silane coupling agent.
The hydrolyzable silicon group is not particularly limited, but an alkoxysilyl group is preferable from the viewpoint of handleability, and a methoxysilyl group and an ethoxysilyl group are particularly preferable from the viewpoint of reactivity.
And it has the haloalkyl group etc. which substituted the alkyl group which does not contain the functional group of a silane coupling agent, a phenyl group, or a part or all of the hydrogen atom with the halogen atom.
Examples of the silane compound include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane. And trifluoropropyltrimethoxysilane.
This silane compound is easily hydrolyzed to form silanol groups, and the silanol groups are bonded to the alloy, so that the alloy is considered to be stabilized in the paint. Since the silanol group is also bonded to the object to be coated at the time of forming the coating film, the adhesion of the coating film is also improved.
From the viewpoint of expression of this effect and storage stability of the paint, the mass ratio of the silane compound to the alloy is preferably 0.01 or more and 0.9 or less, more preferably 0.02 or more and 0.15 or less.

  The undercoat paint of the present invention can contain an appropriate amount of water depending on the method of coating, the film thickness of the coating film, the baking conditions, and the like. It is preferable to do this. In addition to the organic liquid contained as a paste liquid in the alloy paste, an organic liquid can be contained in the paint. For example, an acid such as acetic acid can be used as the organic liquid.

The undercoat paint of the present invention can be obtained by mixing and stirring each component according to a normal production method. At that time, in addition to the above-described components, paint additives such as a wetting and dispersing agent, a wetting agent, an antifoaming agent, a thickening agent, and a pH adjusting agent may be blended. For example, wetting agents such as polycarboxylic acid-based wet dispersing agents, organic phosphate esters, diester sulfosuccinates such as sodium bistridecyl sulfosuccinate, silicone-based or acrylic-based additives, which are general paint additives An antifoaming agent etc. can be mix | blended.
Examples of thickeners include hydroxyethyl cellulose, methyl cellulose, methyl hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, methyl ethyl cellulose ethers, and mixtures of these substances.

In the type containing the zinc powder, the undercoat paint of the present invention may contain a mercapto group, an organic compound covering the zinc powder, and a nitrate.
In addition, the undercoat paint of the present invention is an alloy-containing type, boron nitride, ion-exchanged silica obtained by binding at least one of calcium and magnesium to silica by ion exchange, scaly silica, aqueous zirconia sol, and conductive You may make it contain at least 1 sort (s) of a pigment. Examples of the conductive pigment include those obtained by using a rutile type or anatase type titanium oxide as a base material and forming a coating layer having tin oxide containing antimony on the surface of the base material.

  Since the undercoat paint according to the present invention contains the above-mentioned silane coupling agent or silane compound, when coated with the paint, the adhesion between aluminum and the object to be coated is good, and chromic anhydride, sodium chromate It is not necessary to contain a water-soluble chromium compound such as potassium chromate, sodium dichromate or potassium dichromate. Therefore, there is no environmental problem.

4). Coating The undercoat paint of the present invention can be applied to an object by immersion treatment such as immersion drain (dip drain) and immersion rotation (dip spin), brush coating, spraying, or the like.
Similarly, the top coating composition of the present invention can be applied on a coating film containing zinc or a plating film containing zinc, such as a coating film obtained by the undercoating paint.

After applying the undercoat paint of the present invention to the article to be coated, it is preferable to heat cure the paint. It is preferable to evaporate the volatile component of the paint in advance by drying before curing. The drying temperature is preferably about 100 ° C to 180 ° C. The drying time is preferably about 2 to 25 minutes.
The heat curing of the paint can be performed by hot air oven curing, but infrared baking and induction curing can also be employed. The heat curing can be performed in a range of approximately 280 ° C to 370 ° C. The curing time is preferably about 10 minutes to 45 minutes.
The top coating material of the present invention is preferably baked at about 100 ° C. to 200 ° C. for 10 to 60 minutes.
The coating material of the present invention may be applied to an object to be coated a plurality of times.
In terms of expression and the cost of good corrosion resistance, the coating amount of ^{5mg / dm 2 ~400mg / dm 2} , preferably the total thickness of the coating film is coated to a 1 to 30 [mu] m. And when forming a 2nd coating film and a 1st coating film in a to-be-coated article, it is preferable that the total film thickness of both coating films is 5-30 micrometers, and the coating amount is 50-400 mg.

Since the top coating composition of the present invention configured as described above contains lithium silicate in addition to sodium silicate, it can have a good balance between rust prevention and water resistance. And when it coats on the 2nd coating film or zinc-iron alloy undercoat which contains zinc formed in a thing to be coated, since it contains aluminum which has a larger ionization tendency than zinc, the sacrifice which suppresses corrosion of zinc Since sodium silicate reacts with zinc in combination with the anticorrosive action, the antirust property of the second coating film containing zinc or the zinc-iron alloy base coating film is maintained over a long period of time. Therefore, for example, the corrosion resistance when the article to be coated includes an iron-based base material is maintained over a long period of time.
In addition, since the top coating composition of the present invention contains a silane compound and a surfactant, the silane compound becomes easily hydrolyzed by the surfactant, and the silanol group generated by the hydrolysis binds to the aluminum. Is stabilized in the paint.

  Hereinafter, although an example and a comparative example of the present invention are explained concretely, the present invention is not limited to this example.

1. Investigation of surfactants We investigated the surfactants added to disperse the alloy well in the paint.
The surfactants studied are as follows.
Polyoxyethylene alkylamine of the above formula (1) Trade name “Zontes AL-5” (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)
Product name "Amate 105" (manufactured by Kao Corporation)
Product name "AMIET 102" (manufactured by Kao Corporation)

Polyoxyethylene alkyl ether of the formula (2) Trade name “Marpon ACF-12” (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)
Product name “Marpon ACF-9” (Matsumoto Yushi Seiyaku Co., Ltd.)
Product name "Marpon B-9W" (Matsumoto Yushi Seiyaku Co., Ltd.)
Product name "Marpon ACF-7" (Matsumoto Yushi Seiyaku Co., Ltd.)
Product name "Marpon B-5" (Matsumoto Yushi Seiyaku Co., Ltd.)
Product name “Emulgen 106” (manufactured by Kao Corporation)
Product name “Emulgen 102KG” (manufactured by Kao Corporation)

Polyoxyethylene distyrenated phenyl ether of the formula (3) Trade name “Emulgen A-60” (manufactured by Kao Corporation)
Product name "Emulgen A-90" (manufactured by Kao Corporation)

Polyoxyethylene sorbitan fatty acid ester of the formula (4) Trade name “NIKKOL TS-106V” (manufactured by Nikko Chemicals Co., Ltd.)
Product name "New Coal 25" (Nippon Emulsifier Co., Ltd.)

Sorbitan fatty acid ester of the formula (5) Trade name “Marpon S-20A” (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)

  The HLB of each surfactant is shown in Tables 1 to 3 below.

[Formulation Example 1]
In accordance with the formulation (shown in parts by mass) in Table 1 above, water, a surfactant (the “Zontes AL-5”), and a Zn—Al alloy paste (“STAPA 4 ZnAl7” manufactured by Eckert) were added at room temperature. The composition of Formulation Example 1 was obtained by stirring and mixing for a period of time. The components of “STAPA 4 ZnAl7” are Zn: 85% by mass, Al: 7% by mass, and mineral spirit: 8% by mass.
[Composition Examples 2 to 10]
In accordance with the composition shown in Table 1, the compositions of Composition Examples 2 to 10 were obtained in the same manner as Formulation Example 1. [Formulation Example 11]
A composition of Formulation Example 11 was obtained in the same manner as Formulation Example 1 except that the surfactant was not added.

[Composition Examples 12-16]
In accordance with the formulation shown in Table 2, the formulations were obtained in the same manner as in Formulation Example 1 except for Formulation Examples 12-16.

[Formulation Examples 17 to 26]
According to the formulation shown in Table 3, two or three kinds of surfactants were used, and the compositions of Formulation Examples 17 to 26 were obtained in the same manner as Formulation Example 1. In addition, in the blending examples 17 to 26, water, a surfactant, an alloy, and water are blended in this order, and water is blended twice.

[Evaluation of dispersibility]
The dispersibility in the composition of the Zn-Al alloy after preparation of the composition was evaluated as follows.
A ... very good B ... good C ... bad D ... very bad (alloy plays water)
The evaluation results are shown in Tables 1 to 3 above.

From Table 1, in the case of the polyoxyethylene alkylamine of the formula (1), it can be seen that any surfactant exhibits good dispersibility (HLB 6.3 to 10.9).
In the case of the polyoxyethylene alkyl ether of the formula (2), “Marpon ACF-9” showing the same HLB13.3 has a dispersibility evaluation of C, and “Marpon B-9W” has an evaluation of B. “Marpon ACF-7” of HLB12.1 is also rated B, “Marpon B-5” and “Emulgen 106” of HLB10.9 and 10.5 are both rated A, and “ "Emulgen 102KG" is rated C. Therefore, in the case of polyoxyethylene alkyl ether, it is guessed that HLB10-13 is preferable and HLB10-11 is more preferable.
In the case of Formulation Example 11 where no surfactant is added, the dispersibility of the alloy is very poor.

From Table 2, when the surfactants of formulas (3) to (5) (polyoxyethylene distyrenated phenyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester) are used alone, “Emulgen A-60” It can be seen that only (HLB12.8) is evaluation B, and the other surfactant is evaluation C.
From Table 3, dispersibility does not improve even if two surfactants of formula (3) and two surfactants of formula (4) are mixed, and the surfactants of formulas (4) and (5) It is confirmed that the evaluation becomes B when HLB12 to 15 is mixed and the evaluation becomes A when the surfactant of formula (2) is further mixed to HLB9.9 and 13.3. It was. Even in the same HLB, the blending example 25 in which the amount of the Zn—Al alloy paste is double is slightly worse than the blending example 26.
When a paint is prepared using a surfactant having a dispersibility evaluation of B or higher, the alloy is considered to be well dispersed in any paint.
A similar tendency is considered to be exhibited in the surfactant of the top coat. It has been confirmed that dispersibility of “Zontes AL-5” and “Marpon ACF-7” is good in the top coat.

2. Preparation of undercoat paint [Formulation Example I]
According to the composition (shown in parts by mass) shown in Table 4 below, water, surfactant (1) (said “NIKKOL TS-106V”), surfactant (2) (said “Marpon S-20A”), surfactant Agent (3) (“New Coal 25”), wetting and dispersing agent (“Solsperse 20000”, manufactured by Nippon Lubrizol Corporation), Zn—Al alloy paste (1) (“STAPA 4 ZnAl7”), silane coupling Agent ("S510" manufactured by JNC Corporation, 3-glycidoxypropyltrimethoxysilane), acetic acid, water, thickener ("BYK-425" manufactured by Big Chemie Japan Co., Ltd.), urethane thickener (rheology control agent) )) Was mixed and stirred for 4 hours to obtain an undercoat paint of Formulation Example I.

[Composition Examples II to VI]
According to the formulation shown in Table 4, undercoats of Formulation Examples II to VI were obtained in the same manner as Formulation Example I. In Formulation Examples IV to VI, instead of the Zn—Al alloy paste (1), the Zn—Al alloy paste (2) (“STAPA 4 ZnAl3” manufactured by Ecart Co.) was used. The components of “STAPA 4 ZnAl 3” are Zn: 89% by mass, Al: 2.5% by mass, and mineral spirit: 8.5% by mass.

3. Preparation of Top Coating (1) Examination of Compounding Ratio of Sodium Silicate and Lithium Silicate According to the formulation shown in Table 5 below, a coating containing sodium silicate and lithium silicate was prepared and its moisture resistance was evaluated.

Each paint was applied to a glass plate using a “6 mil doctor blade”, held at 120 ° C. for 15 minutes, and then baked at 180 ° C. for 25 minutes. Each of the obtained coated glass plates was put into a test tank, and the residue was calculated from the mass ratio before and after the addition. The test conditions are as follows.
Test conditions Test chamber temperature: 50 ° C., relative humidity: 90% or more, test time: 15 hours

Table 5 shows the residue and the evaluation of moisture resistance based on this residue. The weight loss was dissolved in water and disappeared. Evaluation is performed as follows.
○: Residue 75% or more × ... Residue less than 75% From Table 5, when the mass ratio of sodium silicate to lithium silicate is 40/60 to 88/12, good moisture resistance is obtained. I understand.

(2) Preparation of top coat [Example 1]
In accordance with the formulation (shown in parts by mass) shown in Table 6 below, an aluminum paste ("FW610" manufactured by Asahi Kasei Chemicals Corporation, 60% active ingredient (aluminum content)), a surfactant ("Zontes AL-5"), Mica pigment ("Iriotec8800" manufactured by Merck & Co., Inc.), n-hexyltrimethoxysilane, water, sodium silicate ("Sodium silicate 2" manufactured by Fuji Chemical Co., Ltd., 51% active ingredient), and lithium silicate (Nippon Chemical Industry Co., Ltd.) The topcoat paint of Example 1 was obtained by mixing and stirring “lithium silicate 45” manufactured by company, active ingredient 23%).

In Table 6, stability in water, mass of active ingredient of sodium silicate and lithium silicate (%), PWC, mass ratio of active ingredient of aluminum paste to active ingredient of sodium silicate (%), active ingredient of aluminum paste Mass ratio of lithium silicate to active ingredient (%), mass ratio of mica pigment to active ingredient of sodium silicate (%), mass ratio of mica pigment to active ingredient of lithium silicate (%), effective aluminum paste as pigment The mass (%) of the component and mica pigment is shown. PWC is calculated | required by the following formula | equation.
PWC = (active ingredient of aluminum paste + mica pigment) / (active ingredient of aluminum paste + mica pigment + active ingredient of sodium silicate + active ingredient of lithium silicate) × 100

The manufacturer's standards for “Soda Silica No. 2” are as follows.
[1] SiO ₂ : 27.7 to 29.4 (%)
[2] Na ₂ O: 11.5 to 12.5 (%)
[3] Molar ratio ([1] / [2]): 2.4-2.5

The manufacturer's standard for “lithium silicate 45” is as follows.
[1] SiO ₂ : 20-22 (%)
[2] Li ₂ O: 2.2 to 2.5 (%)
[3] Molar ratio ([1] / [2]): 4.2 to 4.8

[Examples 2 to 13]
According to the composition in Table 6 above, topcoat paints of Examples 2 to 13 were obtained in the same manner as in Example 1.

[Comparative Example 1]
As shown in Table 7 below, the top coat of Comparative Example 1 was made in the same manner as in Example 1 except that aluminum paste, surfactant, n-hexyltrimethoxysilane, mica pigment, and lithium silicate were not blended. Got.

[Comparative Example 2]
As shown in Table 7 above, the top coat of Comparative Example 2 was made in the same manner as in Example 1 except that the aluminum paste, surfactant, n-hexyltrimethoxysilane, mica pigment, and sodium silicate were not blended. Got.
[Comparative Example 3]
As shown in Table 7 above, an overcoat paint of Comparative Example 3 was obtained in the same manner as in Example 1 except that the surfactant, n-hexyltrimethoxysilane, and mica pigment were not blended.

The evaluation of “stability in water” in Tables 6 and 7 is as follows.
○: No gas generation in the paint ×: Gas generation in the paint From Table 6 and Table 7, in the case of the paint of Comparative Example 3 containing no surfactant and n-hexyltrimethoxysilane, aluminum is contained in the paint. It turns out that it was not stable and reacted with water to produce gas. That is, it is understood that a surfactant and n-hexyltrimethoxysilane are necessary for stabilizing aluminum in a water-based paint.

4). Production of corrosion-resistant surface-treated bolts (when forming the second coating film)
[Example 21]
After the surface of the bolt (M10: steel) was degreased and shot blasted, the surface was coated by the dip spin method using the undercoat paint of Formulation Example I and dried before curing at 120 ° C. for 15 minutes. Then, it hardened | cured for 25 minutes at 330 degreeC, and formed the coating film. Again, coating was performed using the same undercoat. That is, coating was performed twice to form a second coating film.
Next, the surface of the second coating film was coated by the dip spin method using the top coat paint of Example 1 and cured at 180 ° C. for 40 minutes to form the first coating film. A treated bolt was produced. The total film thickness was 30 μm, and the coating amount was 400 mg / dm ² . The composition of the paint is shown in Table 8 below.

[Examples 22 to 30]
Corrosion-resistant surface-treated bolts of Examples 22 to 30 were produced in the same manner as in Example 21 except that the top coat was replaced with the top coat of Examples 2 to 10 according to the configuration in Table 8 above.

[Examples 31 to 40]
Corrosion-resistant surface-treated bolts of Examples 31 to 40 were produced in the same manner as in Example 21 except that the undercoat paint was changed to the undercoat paint of Formulation Example II in accordance with the configuration shown in Table 9 below.

[Examples 41 to 50]
Corrosion-resistant surface-treated bolts of Examples 41 to 50 were produced in the same manner as Example 41 except that the undercoat paint was changed to the undercoat paint of Formulation Example III according to the composition of the paint shown in Table 10 below.

[Examples 51 to 60]
Corrosion-resistant surface-treated bolts of Examples 51 to 60 were produced in the same manner as Example 21 except that the undercoat paint was changed to the undercoat paint of Formulation Example IV according to the composition of the paint shown in Table 11 below.

[Examples 61 to 70]
Corrosion-resistant surface-treated bolts of Examples 61 to 70 were produced in the same manner as Example 21 except that the undercoat paint was replaced with the undercoat paint of Formulation Example V according to the composition of the paint shown in Table 12 below.

[Examples 71 to 80]
Corrosion-resistant surface-treated bolts of Examples 71 to 80 were produced in the same manner as Example 21 except that the undercoat paint was changed to the undercoat paint of Formulation Example VI in accordance with the composition of the paint shown in Table 13 below.

[Examples 81 to 89]
Corrosion-resistant surface-treated bolts of Examples 81 to 89 were produced in the same manner as Example 21 according to the composition of the coating material shown in Table 14 below.

[Examples 90 to 98]
Corrosion-resistant surface-treated bolts of Examples 90 to 98 were produced in the same manner as Example 21 according to the composition of the coating material shown in Table 15 below.

[Comparative Examples 11 to 16]
According to the composition of the coating material shown in Table 16 below, the undercoating material was formed as Example 21 except that the second coating film was formed using the coating materials of Formulation Examples I to VI and the first coating film was not formed using the top coating material. Similarly, the surface-treated bolts of Comparative Examples 11 to 16 were produced.

[Comparative Examples 17-22]
According to the composition of the paint in Table 16 above, the undercoat paint was formed using the paints of Formulation Examples I to VI, and the first paint film was formed using the top coat paint of Comparative Example 1, In the same manner as in Example 21, surface treated bolts of Comparative Examples 17 to 22 were produced.

[Comparative Examples 23 to 28]
According to the composition of the coating material shown in Table 17 below, the undercoat paint was formed using the paints of Formulation Examples I to VI, and the first paint film was formed using the top coat paint of Comparative Example 2, In the same manner as in Example 21, surface treated bolts of Comparative Examples 23 to 28 were produced.

[Salt spray test (corrosion resistance evaluation test)]
About the corrosion-resistant surface treatment bolt of the above-mentioned Example and the surface treatment bolt of the comparative example, the salt spray test was done based on "JIS-K5600-7-1", and it evaluated as follows. The results are shown in Tables 8 to 15 above.
◎: No red rust after 1500 hours of salt spray test ○: No red rust after 1000 hours of salt water test ○ Slightly generated red rust after 1500 hours ○ ^- : Little red rust after 1000 hours of salt spray test ×: Red rust occurs after 1000 hours of salt spray test XX: The first coating film dissolves and disappears after 1000 hours of salt spray test
XXX: The first coating film cannot be formed

5. Production of corrosion-resistant surface-treated bolts (when the second coating film is not formed and the zinc-iron alloy base coating is formed by impact galvanization)
Example 99
As shown in Table 18 below, after a zinc-iron alloy undercoating was formed on the surface of the bolt by impact galvanization, the surface of the zinc-iron alloy undercoating was formed by the dip spin method using the top coat of Example 3. It was coated and cured at 180 ° C. for 40 minutes to form a coating film. Again, painting was performed using the same top coat. That is, coating was performed twice to form a first coating film, and a corrosion-resistant surface-treated bolt of Example 99 was produced.

[Example 100]
A corrosion-resistant surface-treated bolt of Example 100 was produced in the same manner as in Example 99 except that the top coat paint of Example 4 was used.

[Comparative Example 29]
A surface-treated bolt of Comparative Example 29 was produced in the same manner as in Example 99 except that the first coating film was not formed.

[Salt spray test (corrosion resistance evaluation test)]
About the corrosion-resistant surface treatment bolt of the above-mentioned Example and the surface treatment bolt of the comparative example, the salt spray test was done based on "JIS-K5600-7-1", and it evaluated as follows. The results are shown in Table 18 above.
○: No red rust after 1000 hours of salt spray test ×: Red rust generated after less than 100 hours of salt spray test

6). Discussion In Tables 8 to 17, in the case of the surface-treated bolts of Comparative Examples 11 to 16 that do not form the first coating film, the occurrence of red rust was confirmed after 1000 hours of the salt spray test, whereas in the case of the Examples, 1000 It can be seen that red rust does not occur over time and the corrosion resistance is improved.
Moreover, in the case of the surface treatment bolt of Comparative Examples 17-22 using the top coat of Comparative Example 1 containing only sodium silicate and not containing aluminum paste and mica pigment, the first coating film dissolves in 1000 hours of the salt spray test. Disappeared and red rust occurred. That is, when the top coating does not contain lithium silicate, the water resistance is poor and the first coating film cannot be maintained.
And in the case of the surface treatment volt | bolt of the comparative examples 23-28 using the top-coat paint of the comparative example 2 which does not contain an aluminum paste and a mica pigment but contains only lithium silicate, a 1st coating film cannot be formed, The corrosion resistance cannot be improved by one coating film.

  In the case of Examples 28, 38, 48, 58, 68, and 78 using the top coat of Example 8 containing mica pigment, the top coat of Example 7 having the same composition except that no mica pigment was used was used. Corrosion resistance is further improved compared to the cases of Examples 27, 37, 47, 57, 67 and 77, and by adding a mica pigment in addition to the aluminum pigment (increasing PWC), the corrosion resistance may be further improved. I understand.

As described above, it is preferable that the mass ratio of sodium silicate and lithium silicate is 40/60 to 88/12 from the viewpoint of developing good moisture resistance. In the corrosion-resistant surface-treated bolts of Examples 83, 86, 89, 92, 95, and 98, the top coat of Example 13 in which the mass ratio of sodium silicate to lithium silicate is 50.6 / 49.4 is used. . The evaluation of the corrosion resistance of these top coats is “◯ ⁻ ”, and it is understood that the mass ratio is preferably 50/50 to 88/12 in order to obtain good corrosion resistance in addition to good moisture resistance. .
By comparing the examples of the corrosion-resistant surface-treated bolts using the top coating of Examples 4, 6, 8, 10, and 13, the lower limit of the mass ratio of sodium silicate and lithium silicate is 60/40. It is more preferable that 72/28 is even more preferable. And it turns out that it is most preferable that it is 74/26-86/14.

  Moreover, from Table 18, in the case of Example 99 and Example 100 which do not form a 2nd coating film and form a 1st coating film after forming a zinc-iron alloy base film, a 1st coating film is not formed. It can be seen that the corrosion resistance is greatly improved as compared with Comparative Example 29.

  As described above, since the top coating composition of the present invention contains lithium silicate in addition to sodium silicate, it was confirmed that it can have a good balance between rust prevention and water resistance. And when it coated on the 2nd coating film or zinc-iron alloy base film containing zinc, it was confirmed that a coated article has favorable corrosion resistance over a long period of time. The second coating film is not limited to the second coating film formed using the above-described undercoating paint having an alloy containing zinc and aluminum, but using an undercoating paint containing a single zinc powder and aluminum powder. Even if it is formed, it is presumed that the same effect is produced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not intended to include the above-described meanings, but is intended to include meanings equivalent to the claims and all modifications within the scope of the claims. For example, lithium silicate is not limited to “lithium silicate 45” used in the embodiment, and lithium silicate 35 and lithium silicate 75 may be used. The mica pigment may also be coated with a metal oxide such as titanium oxide or iron oxide.

Claims (8)

A paint to be applied to a coating film or a plating film containing zinc,
With aluminum,
Sodium silicate,
Lithium silicate,
A silane compound;
A surfactant,
Ri greens contain the water,
Coating weight ratio of the active ingredient of the lithium silicate of the active ingredient of the sodium silicate is characterized by der Rukoto 50/50 or 88/12 or less. The silane compound, in the molecule, an alkyl group, a phenyl group, or a haloalkyl group part or the whole substituted with a halogen atom of the hydrogen atoms, in claim 1, characterized in that it comprises a hydrolyzable silicon group The paint described. The surfactant is selected from the group consisting of polyoxyethylene alkylamines, polyoxyethylene alkyl ethers, polyoxyethylene distyrenated phenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and alkyl ether phosphate salts. The paint according to claim 1 or 2 , wherein the paint is at least one. The paint according to any one of claims 1 to 3 , further comprising a mica pigment. A coated article comprising a first coating film formed using the paint according to any one of claims 1 to 4 on an article to be coated containing an iron-based base material. The coated article according to claim 5 , further comprising a zinc-iron alloy undercoating formed by impact galvanization between the surface of the iron-based base material and the first coating film. Having a second coating film formed on the surface of the iron-based base material or on the zinc-iron alloy undercoating using an undercoat paint having zinc powder or a powdered alloy containing zinc and aluminum; The coated article according to claim 5 or 6 . The undercoat paint is
Silane coupling agent having at least one functional group selected from the group consisting of epoxy group, methacryloxy group, acryloxy group, amino group, and vinyl group and hydrolyzable silicon group in the molecule, and / or in the molecule A silane compound having a hydrolyzable silicon group and excluding a silane coupling agent;
The coated article according to claim 7 , comprising a surfactant.