JP2011149452A - Corrosion resistant surface treated sprocket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a corrosion resistant surface treated sprocket manufactured without having adverse effect on an environment, given corrosion treatment without degrading strength even when using an inexpensive material, providing a coating film with excellent adhesiveness and restrained from the formation of coating film powder during manufacture, use, or the like so as to excel in work efficiency, appearance quality and corrosion resistance. <P>SOLUTION: The sprocket 10 includes tooth parts 11, 11 ... meshed with a roller of a roller chain, substantially at the center part in the thickness direction. A nickel-based coating is formed on an iron-based base material on the side faces of the tooth parts 11, and further a first coating film is formed using a water-based rust-proof coating material containing zinc, nitrate and an organic compound containing a mercapto group other than a silane coupling agent containing a mercapto group. A second coating film is formed on the first coating film, using a top coat containing a pigment, sodium silicate and acrylic emulsion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is used in a corrosive atmosphere such as salt water, acid, alkali, etc., a nickel-based film is formed on the surface, and a coating film is formed on the nickel-based film using a paint having good rust prevention properties. The present invention relates to a formed corrosion-resistant surface-treated sprocket.

Conventionally, as a sprocket used in a corrosive atmosphere such as salt water, acid, alkali or the like, there is one using stainless steel such as austenitic stainless steel (for example, Patent Document 1).
However, since stainless steel such as austenitic stainless steel is expensive, it is required to obtain a high-strength sprocket using an inexpensive material. Therefore, in order to prevent corrosion, the surface of the iron base material of the sprocket is coated with a metal that is lower than iron such as zinc, or is coated with a metal that is noble than iron such as nickel. Examples of the former galvanization include electrogalvanization and powder impact galvanization, and examples of the latter nickel plating include electronickel plating and electroless nickel plating. Furthermore, a chromate film is also formed on a zinc film formed by electrogalvanization.

  In Patent Document 2, a zinc film is formed on a surface of iron in a non-hydrogen atmosphere, and a water-based anticorrosive paint containing aluminum powder and silicone resin is baked on the zinc film to prevent white rust. Inventions for anticorrosive chain parts and sprockets having a coating film formed thereon are disclosed.

Japanese Patent Laid-Open No. 2003-112005 Japanese Patent No. 3122037

When a zinc film is formed on the iron base material of the sprocket described above by electroplating, and further a chromate film is formed for anticorrosion treatment, hydrogen embrittlement may occur due to acid cleaning or the like during the electroplating process.
In addition, when a coating film is formed on the surface of the sprocket using the above-mentioned water-based anticorrosive paint, coating powder is likely to be generated when it is rubbed during sprocket manufacturing and use, etc. There is a problem that the appearance quality of the sprocket is deteriorated, the coating film is partially thinned and the anticorrosion performance is lowered.

  The present invention has been made in view of such circumstances, has good corrosion resistance, and even when pinholes are formed in the coating or the coating is peeled off, rusting is suppressed, and an inexpensive base material is used. Corrosion resistance can be applied without lowering the strength of the coating film, and the coating film has good adhesion. An object of the present invention is to provide a corrosion-resistant surface-treated sprocket having good appearance quality, good corrosion resistance, and good corrosion resistance.

  A corrosion-resistant surface-treated sprocket according to a first aspect of the present invention is the corrosion-resistant surface-treated sprocket made of an iron-based material, having a tooth portion that engages with a chain on the outer periphery, and having a nickel-based film formed on the surface. On top of the first coating film formed using a water-based anticorrosive paint containing an organic compound containing a mercapto group other than zinc, nitrate, and a mercapto group-containing silane coupling agent, It has a 2nd coating film formed using the top coat paint containing a pigment, sodium silicate, and an acrylic emulsion or a polyurethane aqueous composition.

Here, the iron-based material means iron or an iron alloy containing iron as a main component, and the iron alloy contains carbon, silicon, magnesium, cerium, nickel, chromium, molybdenum, copper, and the like together with iron. Things. Specific examples of the iron alloy include steel and cast iron.
The acrylic emulsion refers to an emulsion obtained by emulsion polymerization of a monomer mainly composed of an acrylic acid monomer using an aqueous emulsifier.
In addition, the polyurethane aqueous composition is obtained by blending a urethane prepolymer compound obtained by reacting an isocyanate group-containing compound and an active hydrogen group-containing compound and dispersing it in water (urethane emulsion). Or obtained by dissolving. The active hydrogen group is a functional group containing hydrogen that reacts with an isocyanate group, and examples thereof include a hydroxyl group, a primary or secondary amino group, and a thiol group.

In the water-based anticorrosive paint, since zinc is coated with the organic compound, the reaction between zinc and water is sufficiently suppressed, and the storage stability is good. In the present invention, since the first coating film is formed on the nickel-based film using the water-based anticorrosive paint, the zinc contained effectively in the first coating film effectively sacrifices zinc. The anticorrosive action is exhibited, the occurrence of red rust is suppressed, and the durability of the sprocket is improved. When only a nickel-based film is formed on an iron-based base material, rusting cannot be suppressed when pinholes occur. In the present invention, the first and second coating films are formed to form a three-layer structure. Therefore, rusting is suppressed. And even when a coating film peels partly by a hit, a hammer, etc., rusting is suppressed by a nickel-type coating film.
In addition, since the coating and the coating have good antirust properties, inexpensive carbon steel can be used as the sprocket material. And when nickel-based film is formed by electroless plating, there is no process such as acid cleaning, so hydrogen embrittlement does not occur, and it is possible to perform anticorrosion treatment without lowering the strength of the iron-based base material. Even when strength is not reduced.

  And in this invention, since the 2nd coating film is formed using the said top coat, the penetration | invasion of corrosion factors, such as salt water, can be prevented and the thin film of a coating film can be achieved. Moreover, since the 2nd coating film is formed, it is prevented that a lower layer coating film is wrinkled, and rusting is suppressed when the lower layer coating film is wrinkled. Furthermore, since the adhesiveness of the coating film is good, repair during production is suppressed. And since generation | occurrence | production of a coating-film powder is suppressed at the time of manufacture and use, workability | operativity and an external appearance quality are favorable, the film thickness of a coating film is hold | maintained uniformly and favorable corrosion resistance is hold | maintained. .

The corrosion-resistant surface-treated sprocket according to the second invention is the first invention, wherein the acrylic emulsion of the top coat is a polymerizable monomer containing an alkoxysilyl group and a monomer having an ethylenic double bond. It is formed by emulsion polymerization, and the mass ratio of the active ingredient of the sodium silicate and the active ingredient of the acrylic emulsion is 0.1 or more and 17 or less.
In the present invention, the rust prevention and adhesion of the second coating film are further improved.

The corrosion-resistant surface-treated sprocket according to a third aspect of the present invention is the first aspect of the invention, wherein the polyurethane aqueous composition of the top coating comprises a polyurethane resin containing at least one silanol group in the molecule, and a strongly basic tertiary amine And the mass ratio of the active ingredient of the sodium silicate and the active ingredient of the polyurethane aqueous composition is from 0.1 to 17 inclusive.
In the present invention, the rust prevention and adhesion of the second coating film are further improved.

The corrosion-resistant surface-treated sprocket according to a fourth aspect of the present invention is the first aspect of the third aspect, wherein the pigment of the top coat is a mica powder pigment or a mica titanium pigment, the pigment, the pigment, and the sodium silicate The mass ratio of the active ingredient and the total weight of the active ingredients of the acrylic emulsion or aqueous polyurethane composition is 0.08 or more and 0.5 or less.
In the present invention, the second coating film has a good balance between rust prevention and adhesion.

The corrosion-resistant surface-treated sprocket according to a fifth aspect of the present invention is any one of the first to fourth aspects, wherein the nickel-based film is formed by electroless plating, and a nickel film, a nickel-phosphorus alloy film, a nickel-boron alloy film, It is a nickel-phosphorus-boron alloy film, a nickel-iron-phosphorus alloy film, a nickel-cobalt-phosphorus alloy film, or a nickel-phosphorus-PTFE alloy film.
In the present invention, hydrogen embrittlement does not occur and wear resistance is good.

  According to the present invention, a water-based anticorrosive paint containing an organic compound containing a mercapto group other than zinc, nitrate, and a mercapto group-containing silane coupling agent on a nickel-based film formed on an iron-based base material of a sprocket. Since the 1st coating film is formed using, a pinhole arises in a film | membrane, or when a coating film peels, rusting is suppressed. Even when an inexpensive material is used as the sprocket material, the anticorrosion treatment is performed without lowering the strength, and good corrosion resistance is maintained.

  In addition, according to the present invention, the second coating film is formed on the first coating film using a top coating material containing a pigment, sodium silicate, and an acrylic emulsion or a polyurethane aqueous composition. The production of coating powder is suppressed during production and use, workability and appearance quality are improved, repair after assembly is unnecessary, and the film thickness of the coating is kept uniform. Good corrosion resistance is maintained. Therefore, the corrosion-resistant surface-treated sprocket has good durability.

A book having teeth on the outer periphery that engage with the roller chain, and coating the coatings according to Formulation Examples 1 and 2 on the side surfaces of the teeth to form the first coating film and the second coating film. It is a perspective view which shows the sprocket of Example 1 of the corrosion-resistant surface treatment sprocket of invention. It is an expanded sectional view which shows A part of FIG. (A) is Example 1-6, Example 12-20, 23, 24, 26-28, and the amount of coating-film powder | flour deposited when producing the sprocket of Comparative Example 1, (b) is Example 7, 21. (C) is the amount of coating powder deposited when the sprockets of Examples 8 to 11 and 22 were prepared, and (d) was the sprocket of Comparative Example 2. (E) is a diagram showing the amount of coating powder deposited when the sprocket of Comparative Example 3 was fabricated.

The corrosion-resistant surface-treated sprocket of the present invention is made of an iron-based material and has a tooth portion that engages with a chain on the outer periphery. The sprocket may be configured by combining a plurality of parts, or may be integrally formed.
The corrosion-resistant surface-treated sprocket of the present invention has a nickel-based film formed on at least the surface of the iron-based base material on the side surface of the tooth portion.
The nickel-based film can be formed by electroplating, but is preferably formed by electroless plating. Electroless plating provides a coating that is harder, more homogeneous and denser than electroplating and has high corrosion resistance. Further, since there is no acid cleaning step, hydrogen embrittlement does not occur. By selecting a reducing agent, pure Ni (reducing agent: hydrazine), Ni-P alloy (reducing agent: hypophosphite), Ni-B alloy (borohydride compound), Ni-P-B alloy (reduction) Agent: a combination of hypophosphite and borohydride compound). When an iron salt or a cobalt salt is used in combination, a ternary alloy film such as a Ni—Fe—P alloy or a Ni—Co—P alloy can be formed, and PTFE (polytetrafluoroethylene) is dispersed in the plating bath. In this case, a composite alloy film such as Ni-P-PTFE in which PTFE is dispersed in the above alloy is obtained.

In the present invention, any of the above-described films can be used, but an alloy film containing phosphorus or boron is preferable because the film crystal becomes fine and the surface is smoothed by containing phosphorus or boron. Since the Ni-P-B alloy film is hard and the Ni-P-PTFE alloy film has good slipping property, the wear resistance is further improved.
When carburized steel subjected to low temperature tempering at 150 to 250 ° C. after carburizing is used as the iron base material of the corrosion-resistant surface-treated sprocket of the present invention, a nickel-based coating is used so as not to impair this low-temperature tempering effect. It is preferable to lower the treatment temperature. Moreover, it is preferable that the thickness of a film | membrane is 10-15 micrometers from a viewpoint of corrosion resistance expression and clearance.

  In the corrosion-resistant surface-treated sprocket of the present invention, the first coating film is formed on the above-described nickel-based film using a water-based anticorrosive paint.

  The water-based anticorrosive paint of the present invention contains an organic compound containing a mercapto group other than zinc, nitrate, and a mercapto group-containing silane coupling agent. A water-based anticorrosive pigment is constituted by the zinc, nitrate, the organic compound and the like. The water-based anticorrosive paint may contain a base metal other than zinc, but from the viewpoint of poor storage stability, it is preferable not to contain aluminum as a pigment.

  The content of zinc with respect to the water-based anticorrosive paint is preferably 5% by mass or more and 90% by mass or less. When the content is 5% by mass or more and 90% by mass or less, the sacrificial anticorrosive action of zinc is well expressed.

There is no restriction | limiting in particular about the form of zinc, and it can take forms, such as spherical shape, flake shape, and rod shape. In particular, when a paint is formed using a flake-like material, the coating effect on the article to be coated is high and has excellent corrosion resistance.
When zinc is in the form of flakes, it is preferably obtained by spreading with a ball mill, an attritor or the like and having an average aspect ratio (average major axis / average thickness) of 10 or more.
The flaky zinc powder thus obtained is kneaded with an organic compound containing a mercapto group other than a mercapto group-containing silane coupling agent, and further nitrate is added and kneaded so that zinc is the organic compound. A coated water-based anticorrosive pigment can be obtained. The form may be a powder form or a slurry form.
The nitrate may be added together with the organic compound during the spreading treatment, or may be added during the kneading of the zinc powder and the organic compound as described above.

When performing the spreading treatment described above, the organic compound may be used as a grinding aid, and the metal surface may be directly coated. As a general grinding aid, saturated fatty acids such as stearic acid, oleic acid, etc. You may use unsaturated fatty acid, hydrofluoric acid salt, etc. together.
Furthermore, a surfactant and the above-mentioned grinding aid may be added as a dispersion aid during the spreading treatment and the kneading treatment.

  The kneading treatment can be performed in the presence of an organic solvent, but particularly when a water-soluble solvent is used, the slurry after the treatment can be added as an aqueous anticorrosive pigment as it is to the aqueous anticorrosive paint, which is preferable. .

  Examples of the water-soluble solvent include glycol solvents such as propylene glycol and ethylene glycol, alcohol solvents such as ethanol and isopropanol, glycol ether solvents such as dipropylene glycol monomethyl ether, and the like.

  Examples of the organic compound having a mercapto group include 3-mercaptopropionic acid, ethylhexyl mercaptopropionate, methoxybutyl mercaptopropionate, tridecyl mercaptopropionate, pentaerythritol tetrakispropionate, 4-mercaptophenol, thioglycolic acid, thiol Examples thereof include monoethanolamine glycolate, ethylhexyl thioglycolate, methyl thioglycolate, and ethyl thioglycolate. These organic compounds may be used alone or in combination of two or more.

  The amount of the organic compound added to the zinc powder is preferably 1 to 13 parts by mass, more preferably 3 to 13 parts by mass, further preferably 3 to 10 parts by mass, and 5 to 8% by mass with respect to 100 parts by mass of the zinc powder. Particularly preferred. When the amount added is less than 1 part by mass, it is not sufficient to treat the surface of the zinc powder, the stability in water (storage stability) is insufficient, and the amount added exceeds 13 parts by mass The organic compound becomes excessive, and further improvement in stability in water cannot be expected.

  Examples of the nitrate contained in the water-based rust preventive pigment include potassium nitrate, calcium nitrate, magnesium nitrate, nickel nitrate, and cobalt nitrate. Of these, magnesium nitrate and nickel nitrate are preferable. These nitrates may be used alone or in combination of two or more.

  0.1-10 mass parts is preferable with respect to 100 mass parts of zinc powder, as for the addition amount of nitrate, 3-9 mass parts is more preferable, and 3-7 mass parts is further more preferable. When the addition amount is less than 0.1 parts by mass, it is not sufficient to increase the coating efficiency of the organic compound on the surface of the zinc powder, and the stability of the water-based anticorrosive pigment in water becomes insufficient, and the addition amount When the amount exceeds 10 parts by mass, further improvement in stability in water cannot be expected.

The water-based rust preventive pigment preferably contains a magnesium compound, and more preferably contains the above magnesium nitrate.
The mass ratio of magnesium contained in the water-based anticorrosive pigment to zinc is preferably 0.05% by mass to 10% by mass, more preferably 0.2% by mass to 2.0% by mass. More preferably, the content is 4% by mass to 1.0% by mass. When the proportion is 0.05% by mass to 10% by mass, the aqueous anticorrosive paint is constituted using the aqueous anticorrosive pigment, and when it is applied to the sprocket parts, magnesium elutes before zinc. The amount of zinc elution is suppressed, and the corrosion resistance lasts for a long time.

  The water-based rust preventive pigment may be added to each component separately, or a part or all of the components may be mixed in advance and added as a slurry by mixing with water and the above-mentioned solvent. May be.

  The water-based anticorrosive paint can be obtained by mixing and stirring each component according to a normal production method. In that case, water, alcohol solvents, glycol ether solvents, glycol solvents and other water-soluble solvents, surfactants, surface conditioners, dispersants, dispersion aids, antifoaming additives, etc. Can do. A general paint additive, such as a polycarboxylic acid-based dispersant, a nonionic or anionic surfactant, a urethane-based thickener, a silicon-based or acrylic-based antifoaming agent. In addition, a leveling agent may be added.

  In the corrosion-resistant surface-treated sprocket of the present invention, a second coating film is formed on the first coating film by using a top coating composition to be described later.

The top coating contains a pigment, sodium silicate, and an acrylic emulsion or an aqueous polyurethane composition.
As described above, the acrylic emulsion is obtained by emulsion polymerization of a monomer having an acrylic acid monomer as a main component in an aqueous system using an emulsifier. The monomer may be any compound that forms a cross-linked structure inside or between the polymers of the emulsion and can contribute to improvement of the corrosion resistance, adhesion, etc. of the coating film obtained from the top coat. The acrylic emulsion may contain an inorganic polymer.

Specifically, examples of the acrylic emulsion include those obtained by emulsion polymerization of a polymerizable monomer containing an alkoxysilyl group and a monomer having an ethylenic double bond.
Examples of the aqueous polyurethane composition include those obtained by containing a polyurethane resin containing at least one silanol group in the molecule and a strongly basic tertiary amine. Strongly basic tertiary amines function as curing catalysts. Examples of the strongly basic tertiary amine include 1,8-diazabicyclo [5.4.0] undecene-7 and 1,8-diazabicyclo [3.4.0] nonene-5.

  The polymer of the acrylic emulsion is either a homopolymer of a monomer containing an alkoxysilyl group and having an ethylenic double bond, or a copolymer of the monomer and another monomer having an ethylenic double bond. Also good. Examples of the monomer having an alkoxysilyl group and having an ethylenic double bond include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and vinyltriisopropoxysilane. Examples of other monomers having an ethylenic double bond include butyl methacrylate, 2-ethylhexyl acrylate, cyclohexyl methacrylate, methyl methacrylate, butyl acrylate, ethyl acrylate, methyl acrylate, acrylic acid, and methacrylic acid. As the emulsifier, a known surfactant can be used.

  In the polyurethane aqueous composition, first, a compound having at least two active hydrogen groups per molecule, a compound having at least two isocyanate groups per molecule, and a hydrophilic group in the molecule, at least 1 A compound having one active hydrogen group is reacted to produce a polyurethane prepolymer. Next, the hydrophilic group in the polyurethane prepolymer is neutralized with a neutralizing agent, a strong base tertiary amine is added, and the neutralizing agent and the strongly basic tertiary amine are added to the polyurethane prepolymer. By dispersing or dissolving a compound containing an active hydrogen group capable of reacting with at least one isocyanate group in one molecule and a hydrolyzable silicon group, and other chain extender in water. A polyurethane aqueous composition is obtained.

Since the top coating material contains sodium silicate in addition to the acrylic emulsion or the aqueous polyurethane composition, it has good adhesion and further improved rust prevention.
When an acrylic emulsion is used, the mass ratio between the active ingredient of sodium silicate and the active ingredient of the acrylic emulsion is preferably 0.1 or more and 17 or less. When the mass ratio is 0.1 or more and 17 or less, the coating film formed by the top coating has good rust prevention and adhesion. From the viewpoint of better adhesion, the mass ratio is more preferably 0.1 or more and 4.2 or less, and from the viewpoint of better adhesion, the mass ratio is 0.1 or more and 1.4 or less. Is more preferable, and the mass ratio is particularly preferably 0.2 or more and 1.4 or less from the viewpoint of more excellent rust prevention.

  When the polyurethane aqueous composition is used, the mass ratio of the active ingredient of sodium silicate and the active ingredient of the polyurethane aqueous composition is preferably 0.1 or more and 17 or less. When the mass ratio is 0.1 or more and 17 or less, the coating film formed by the top coating has good rust prevention and adhesion. The mass ratio is more preferably 0.5 or more and 17 or less from the viewpoint of better rust prevention, and the mass ratio is 0.6 or more and 17 or less from the viewpoint of better rust prevention. Preferably, the mass ratio is particularly preferably 0.6 or more and 5.2 or less from the viewpoint of better adhesion, and the mass ratio is 0.6 or more and 2.4 or less from the viewpoint of better rust prevention. Most preferably.

  The pigment is preferably a mica powder pigment containing mica powder or a mica titanium pigment containing mica titanium. Titanium mica is one in which the surface of flaky mica powder is coated with titanium dioxide, and pearly luster is expressed by a thin film interference effect, and mica titanium pigment is a kind of pearl pigment. The pigments may be used alone or in combination.

When a mica powder pigment or a mica titanium pigment is used as the pigment, the mass ratio of the pigment to the total mass of the pigment, the active ingredient of the sodium silicate, and the active ingredient of the acrylic emulsion or aqueous polyurethane composition is 0. It is preferably from 08 to 0.5.
When it has this mass ratio, the balance of the rust prevention property and adhesiveness of a coating film becomes favorable. When the mass ratio exceeds 0.5, it has been confirmed that the adhesion is deteriorated by an adhesion evaluation test described later. Moreover, when using an acrylic emulsion, it is more preferable that the said mass ratio is 0.08 or more and 0.4 or less.
The top coat paint can also contain a second pigment such as stainless flakes in order to impart gloss.

  The top coating material is obtained by mixing and stirring the above-described components according to a normal production method. At that time, water-soluble solvents such as water, alcohol solvents, glycol ether solvents and glycol solvents, and additives for coating materials such as surfactants, dispersants and antifoaming agents can be blended. A general paint additive, such as a polycarboxylic acid-based dispersant, a nonionic or anionic surfactant, a urethane-based thickener, a silicon-based or acrylic-based antifoaming agent. In addition, a leveling agent may be further blended.

The water-based anticorrosive paint and the top coat are applied to the surface of the anticorrosive surface-treated sprocket by a method such as dip spin, and then baked and dried to form the first paint film and the second paint film. . Since the water-based rust preventive paint and the top coat have the above-described composition, baking and drying can be performed at a temperature of 180 ° C. or less, respectively.
Therefore, the sprocket is not reduced in hardness, and the reduction in sprocket strength and sprocket life is suppressed.

Examples of the present invention and comparative examples will be specifically described below, but the present invention is not limited to these examples.
1. Water-based anti-corrosion paint [Formulation Example 1]
According to the composition (shown in parts by mass) shown in Table 1 below, flaky zinc powder (average major axis 15 μm, average thickness 0.5 μm), surfactant, dispersion aid, and ethylhexyl thioglycolate were mixed with dipropylene glycol monomethyl ether. The mixture was stirred for 3 hours, and magnesium nitrate was further added, mixed and stirred to obtain a zinc paste. In this zinc paste, the surface of the zinc powder is coated with ethylhexyl thioglycolate.
To the zinc paste, a dispersant, 3-aminopropyltriethoxysilane (“KBP90” manufactured by Shin-Etsu Chemical Co., Ltd.), water, a fluidity improver (“BYK420” manufactured by Bykchemie Co., Ltd.), an antifoaming agent (San Nopco Co., Ltd.) “SN deformer 1070”) and a surface conditioner were blended to obtain a water-based anticorrosive paint of Formulation Example 1.

2. Top coating (1)
[Formulation Example 2]
In accordance with the composition of Table 2 below, pearl pigment (“Iriodin 103WNT” manufactured by Merck & Co., Inc.), second pigment (active ingredient (residue of heating) 50%), acrylic emulsion [“Yodosol AX-6 manufactured by Henkel Technologies Japan Co., Ltd.” ”, 42% active ingredient (residue on heating), hereinafter referred to as“ AX-6 ”], sodium silicate [JIS-regulated sodium silicate No. 2, 51% active ingredient (residue on heating)], antifoam (San Nopco Co., Ltd.) “SN Deformer 5016”), surfactant, thickener (“AW-15F” manufactured by Fuji Chemi HEC Co., Hydroxyethyl Cellulose), and water are mixed and stirred for 1 hour to top coat Formulation Example 2. A paint (1) was obtained.
In Table 2 and Table 3 below, “sodium silicate / acrylic emulsion” represents the mass ratio between the active ingredient of sodium silicate and the active ingredient of acrylic emulsion, and “PWC (Pigment Weight Concentration)” is the coating film formed. The mass ratio (expressed as a percentage here) of (Iriodin103WNT) and (Iriodin103WNT + AX-6 active ingredient + sodium silicate active ingredient).

[Composition Examples 3 to 12]
The blending was in accordance with the blending of Table 2 or Table 3 below, and in the same manner as Formulation Example 2, Topcoat Paints (1) of Formulation Examples 3 to 12 were obtained.

[Formulation Example 13]
A top coat paint of Formulation Example 13 was obtained in the same manner as Formulation Example 2 without containing sodium silicate and according to the formulation of Table 3 above.
[Formulation Example 14]
A top coat paint of Formulation Example 14 was obtained in the same manner as Formulation Example 2 without containing AX-6 according to the formulation of Table 3 above.

3. Top coating (2)
[Formulation Example 15]
In accordance with the composition of Table 4 below, the pearl pigment, stainless steel flake, polyurethane aqueous composition [“WS5100” manufactured by Mitsui Chemicals, Inc., 30% active ingredient (hereinafter referred to as “heating residue”), hereinafter referred to as “WS5100”], sodium silicate, By mixing and stirring the antifoaming agent, surfactant, thickener (“Kelzan S” manufactured by Sanki Co., Ltd., xanthan gum), and water for 1 hour, a top coating material (2) of Formulation Example 15 was obtained. .
In Table 4 and Table 5 below, “sodium silicate / polyurethane aqueous composition” represents the mass ratio between the active ingredient of sodium silicate and the active ingredient of the polyurethane aqueous composition, and “PWC” is in the formed coating film. (Iriodin103WNT) and (Iriodin103WNT + WS5100 active ingredient + sodium silicate active ingredient) mass ratio (expressed in percentage here).

[Formulation Examples 16 to 31]
The blending was in accordance with the blending of Table 4 or Table 5 below, and in the same manner as Formulation Example 15, top coat paints (2) of Formulation Examples 16 to 31 were obtained.

4). Corrosion-resistant surface treatment sprocket [Example 1]
FIG. 1 has a tooth portion that engages with a roller chain on the outer periphery, and a coating material according to Formulation Example 1 and Formulation Example 2 is applied to the side surface of the tooth portion as shown in Table 6 below. FIG. 2 is a perspective view showing a sprocket 10 of Example 1 of the corrosion-resistant surface-treated sprocket of the present invention formed with a coating film and a second coating film, and FIG. 2 is an enlarged sectional view showing a portion A of FIG.

The sprocket 10 has teeth 11, 11,... That mesh with the rollers of the roller chain at a substantially central portion in the thickness direction.
As the layer structure of the side surfaces of the tooth portions 11, 11,..., The Ni-P alloy film 24, the first coating film 26, and the second coating film 28 are sequentially formed on the iron base material 22 as shown in FIG. Is formed.

  After forming the Ni-P alloy film 24 on the iron base material 22 of the sprocket by electroless plating, the aqueous rust preventive paint of Formulation Example 1 in Table 1 is applied to the Ni-P alloy film 24 by spraying. The first coating film 26 was formed by baking at 180 ° C. Furthermore, the top coating material of Example 1 was applied to the first coating film 26 by spraying and baked at 180 ° C. to form the second coating film 28.

[Examples 2 to 28]
Similarly to the above, on the Ni-P alloy film covering the iron base material on the side surface of the tooth part, a first coating film is formed using the water-based anticorrosive paint of the above-mentioned Formulation Example 1, and on the first coating film. As shown in Table 6 and Table 7 below, a second coating film was formed using the topcoat paint of Formulation Examples 2-31, and sprockets of Examples 2-28 were produced.

[Comparative Examples 1-3]
And like the above, on the Ni-P alloy membrane | film | coat which covers the iron-type base material of a tooth | gear part side, a 1st coating film is formed using the water-system anticorrosion coating material of the said mixing example 1, and this 1st coating film On top of this, a second coating film was formed using the top coat of Formulation Examples 13 and 14, and the sprockets of Comparative Examples 1 and 2 were produced.
Further, a first coating film is formed on the Ni-P alloy film covering the iron base material on the side surface of the tooth portion by using the water-based anticorrosion paint of Formulation Example 1, and a conventional product is formed on the first coating film. A second coating film was formed using the top coating material of No. 1, and the sprocket of Comparative Example 3 was produced. The conventional topcoat paint does not contain sodium silicate and acrylic emulsion, but contains the pearl pigment and the KBP90 as a binder.

5. Performance evaluation [salt spray test (corrosion resistance evaluation test)]
The above-mentioned sprocket was subjected to a salt spray test. The test was performed in accordance with “JIS-K5600-7-1”, and the time until the red rust of the plate was found by visual observation was measured. The results of this test are shown in Tables 2-5.
Furthermore, this test result was evaluated as follows and shown in Table 6 and Table 7 above.
A1: Good A2: Better A3: Even better B: Somewhat impossible C: Impossible

[Adhesion evaluation test]
A filter paper is fixedly arranged on the sprocket assembly device, the components of the sprockets of Examples 1 to 28 and Comparative Examples 1 to 3 are assembled, and the coating powder generated when the sprocket is produced is applied to the filter paper. The amount of sediment was investigated.
FIG. 3 is a diagram schematically showing the amount of coating powder deposited on the filter paper produced when each sprocket is produced, in which (a) shows Examples 1-6, Examples 12-20, 23, 24, 26 to 28 and the amount of coating powder deposited when the sprockets of Comparative Example 1 were produced, (b) is the amount of coating powder deposited when the sprockets of Examples 7, 21, and 25 were produced, (c ) Is the amount of coating powder deposited when the sprockets of Examples 8 to 11 and 22 were produced, (d) was the amount of coating powder deposited when the sprocket of Comparative Example 2 was produced, and (e) was a comparative example. 3 shows the amount of coating powder deposited when the sprocket 3 was produced.
The adhesion was evaluated as follows and shown in Tables 6 and 7 above.
A1: Good (FIG. 3 (a))
A2: Better (Fig. 3 (b))
A3: Even better (FIG. 3 (c))
B: Somewhat impossible (Fig. 3 (d))
C: Impossible (Fig. 3 (e))

[Summary]
From the said Table 6, the sprocket of Examples 1-11 comprised using the top-coat paint of the blending examples 2-12 containing both an acrylic emulsion and sodium silicate is a formula which does not contain any one of an acrylic emulsion and sodium silicate. It can be seen that the corrosion resistance is greatly improved compared to the sprockets of Comparative Examples 1 and 2 configured using the top coating of Examples 13 and 14, and the durability is good.
In addition, as shown in FIG. 3, the sprockets of Examples 1 to 11 and Comparative Example 1 prepared using the topcoat paints of Formulation Examples 2 to 13 have suppressed coating powder generation and good coating film adhesion. I understand that there is. As the mass ratio between the active ingredient of sodium silicate and the active ingredient of the acrylic emulsion increases, the adhesion of the coating film decreases, and the sprocket of Comparative Example 2 decreases in adhesion to such an extent that the workability deteriorates (Evaluation B). ), The adhesion of the sprocket of Comparative Example 3 is further reduced (Evaluation C). Therefore, it was confirmed that the adhesiveness of the coating film is improved when the top coating contains an acrylic emulsion.

The sprockets of Examples 1 to 3 and 8 to 10 were prepared by using the top coat paints of Formulation Examples 2 to 4 and Formulation Examples 9 to 11 having the same blending amounts of sodium silicate and acrylic emulsion, and changing the PWC. By comparing the results of the corrosion resistance evaluation test, it can be seen that the larger the PWC, the better the corrosion resistance.
The content of the pearl pigment is 3.9% by mass, the mass ratio of the active ingredient of sodium silicate and the active ingredient of the acrylic emulsion is 0.28 to 1.32, and the PWC is 26.6%. The sprockets of Examples 4 to 6 produced using the top coat paints of Formulation Examples 5 to 7 have the highest corrosion resistance.

  When the mass ratio of the active ingredient of sodium silicate and the active ingredient of the acrylic emulsion is 0.1 or more and 17 or less, and when the PWC is 0.08 or more and 0.5 or less, the sprocket has the corrosion resistance and the coating film. It can be seen that the adhesiveness is well balanced.

  From Table 7 above, the sprockets of Examples 12 to 28 constituted by using the topcoat paints of Formulation Examples 15 to 31 containing an aqueous polyurethane composition and sodium silicate contained sodium silicate but not an aqueous polyurethane composition. It can be seen that the corrosion resistance is greatly improved as compared with the sprocket of Comparative Example 2 configured by using the top coat paint of Formulation Example 14, and has good durability.

  And, when the mass ratio of the active ingredient of sodium silicate and the active ingredient of the polyurethane aqueous composition is 0.1 or more and 17 or less and the PWC is 0.08 or more and 0.5 or less, the adhesion is good, It has been confirmed that the generation of coating powder is suppressed during the production and use of the sprocket, and it has been confirmed that the sprocket has a good balance between corrosion resistance and adhesion of the coating.

  From the above, it is configured to have a first coating film formed using a nickel-based coating, a water-based anticorrosion coating, and a second coating formed using a top coating on the iron base material of the component. It was confirmed that the corrosion-resistant surface-treated sprocket of the present invention was extremely excellent in corrosion resistance and improved the durability of the sprocket.

  In addition, the second coating prevents the first coating from being peeled off and the generation of coating powder is suppressed, so the workability and appearance quality are good, the coating thickness is kept uniform, and after production It was confirmed that the repair of the coating film can be omitted.

And since the antirust property of a membrane | film | coat and a coating film is favorable, cheap carbon steel etc. can be used as a material of a sprocket. Furthermore, when the nickel-based film is formed by electroless plating, there is no step such as acid cleaning, so hydrogen embrittlement does not occur, and the anticorrosion treatment can be performed without lowering the strength of the iron-based base material. Since the corrosion resistance is good, the strength does not decrease even during use.
Further, the corrosion-resistant surface-treated sprocket of the present invention does not cause the problem of environmental contamination of hexavalent chromium as in the case of forming a chromate film.

10 Sprocket 11 Tooth part 22 Iron base material 24 Ni-P alloy coating 26 First coating 28 Second coating

Claims (5)

Corrosion-resistant surface treatment sprocket made of iron-based material, having teeth on the outer periphery that engage with the chain, and having a nickel-based film formed on the surface.
A first coating film formed on the nickel-based film using a water-based anticorrosive paint containing an organic compound containing a mercapto group other than zinc, nitrate, and a mercapto group-containing silane coupling agent;
A corrosion-resistant surface-treated sprocket comprising: a second coating film formed on the first coating film using a top coating material containing a pigment, sodium silicate, and an acrylic emulsion or a polyurethane aqueous composition. The acrylic emulsion of the top coat paint is obtained by emulsion polymerization of a polymerizable monomer containing an alkoxysilyl group and a monomer having an ethylenic double bond,
The corrosion-resistant surface-treated sprocket according to claim 1, wherein a mass ratio of the active ingredient of the sodium silicate and the active ingredient of the acrylic emulsion is 0.1 or more and 17 or less. The polyurethane aqueous composition of the top coating composition comprises a polyurethane resin containing at least one silanol group in the molecule and a strongly basic tertiary amine,
The corrosion-resistant surface-treated sprocket according to claim 1, wherein a mass ratio of the active ingredient of the sodium silicate and the active ingredient of the aqueous polyurethane composition is 0.1 or more and 17 or less. The pigment of the top coat is a mica powder pigment or a mica titanium pigment,
The mass ratio of the pigment to the total mass of the pigment, the active ingredient of the sodium silicate, and the active ingredient of the acrylic emulsion or polyurethane aqueous composition is 0.08 or more and 0.5 or less. The corrosion-resistant surface-treated sprocket according to any one of claims 1 to 3.   The nickel-based coating is formed by electroless plating, and includes a nickel coating, a nickel-phosphorus alloy coating, a nickel-boron alloy coating, a nickel-phosphorus-boron alloy coating, a nickel-iron-phosphorus alloy coating, and a nickel-cobalt-phosphorus alloy. The corrosion-resistant surface-treated sprocket according to any one of claims 1 to 4, which is a coating or a nickel-phosphorus-PTFE alloy coating.

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