JP2011157600A - Rust prevention coating agent, rust prevention treatment method of metal base, and metallic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rust prevention coating agent which has sufficient storage stability and can impart sufficient rust prevention to a zinc-based metal base only by a film formed from the coating agent. <P>SOLUTION: The rust prevention coating agent contains a film-forming component. The film-forming component consists of at least one selected from the group consisting of an epoxy group-containing silane coupling agent and a hydrolyzate and a hydrolysis condensate of the epoxy group-containing silane coupling agent in an amount of 10 g/L or more and 200 g/L or less, and a thiol compound having two or more thiol groups in a molecule in an amount of 10 g/L or more and 200 g/L or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rust preventive coating agent, a rust preventive treatment method for a metal substrate, and a metal material.

  A zinc-based metal substrate is generally a metal substrate excellent in corrosion resistance, and a galvanized steel sheet manufactured by an electroplating method, a hot dipping method, or the like is generally known. Here, zinc-based metal bases are used to produce metal materials for building materials and home appliances, but when the metal surface containing zinc comes into contact with water or oxygen, it is oxidized and white rust is formed. It is known to occur. Conventionally, in order to prevent the occurrence of such white rust, a surface treatment for imparting rust prevention to the metal surface of the zinc-based metal substrate has been performed.

  Conventionally used surface treatment agents such as chromate treatments and phosphoric acid chromate treatments are known as surface treatment agents. However, based on recent environmental trends, the use of chromium may be limited in the future due to the toxicity of chromium, particularly carcinogenicity. Therefore, it is desired to develop a chromium-free rust preventive agent that does not contain chromium and has a corrosion resistance equivalent to that of a chromate agent.

  As a surface treatment agent that replaces the chromate surface treatment agent, a surface treatment agent in which zirconium, water-dispersible silica, a silane coupling agent, a sulfur-containing compound, or the like is added to an organic resin is known. However, the metal material produced using such a surface treatment agent generally has insufficient weather resistance, and improvement in weather resistance has been desired. In addition, in order for the coating with the surface treatment agent to exhibit sufficient rust prevention properties, the surface treatment agent must contain the above-mentioned zirconium, water-dispersible silica, silane coupling agent, sulfur-containing compound, etc. in addition to the organic resin. However, when the above components are contained, the storage stability and bath stability of the surface treatment agent tend to be inferior, and it has been desired to improve such properties.

  For example, Patent Document 1 discloses a rust preventive coating agent containing an aqueous resin, a triazine thiol compound, and a phosphate ion used on the surface of zinc-coated steel or uncoated steel. By treating a metal substrate, it is said that rust prevention superior to conventional chromate-containing aqueous resin-based anticorrosion coating agents can be exhibited.

  Patent Document 2 discloses a rust preventive coating agent that is used for surface treatment of a galvanized steel sheet and includes a silane coupling agent, a phosphorus-containing ion, and a sulfur-containing compound. It is said that the corrosion resistance superior to the conventional chromate-containing rust preventive agent can be imparted to the galvanized steel sheet by treating the metal substrate.

  Furthermore, in Patent Document 3, a surface treatment composition containing an aqueous epoxy resin dispersion, a silane coupling agent, and phosphoric acid and / or hexafluorometal acid is applied to the surface of a galvanized steel sheet and dried. A surface treatment film was formed; then, an upper layer coating film was formed by applying and drying an upper layer coating composition containing an epoxy group-containing resin, a urethane resin, and an organometallic compound on the upper layer. A corrosion resistant surface treated steel sheet is disclosed.

  Furthermore, in Patent Document 4, a surface treatment composition containing a predetermined phenol resin, a cationic urethane resin, and a silane coupling agent having a predetermined reactive functional group is applied to the surface of a galvanized steel sheet. A surface treatment film is formed by drying; then, a resin containing a solvent-based thermosetting resin, a solid lubricant, and a non-chromium-based anticorrosive additive is applied to the upper layer and cured by heating. A surface-treated steel sheet having a film formed thereon is disclosed.

  In addition, Patent Document 5 discloses a metal surface treatment agent comprising a metal-coated steel sheet having a predetermined content of a silane coupling agent, a predetermined content of water-dispersible silica, and a predetermined content of a zirconium compound. Furthermore, a rust-preventing coating agent containing a resin, a predetermined content of a silane coupling agent, a predetermined content of water-dispersible silica, and a predetermined content of phosphate ions is applied. A metal surface treatment method is disclosed.

JP-A-10-195345 JP 2000-144020 A JP 2008-000910 A JP 2004-018887 A JP 2001-240977 A

  However, since the surface treatment compositions described in Patent Documents 1 and 2 contain phosphate ions, the storage stability of the surface treatment composition is not sufficient. Moreover, even if the surface treatment film is formed using the surface treatment composition described in Patent Documents 3 to 5, the surface treatment film alone is insufficient in the rust preventive property given to the zinc-based metal substrate, It was necessary to further form a coating film on the upper layer of the surface treatment film. In general, as a method of imparting corrosion resistance to a metal substrate, after performing a surface treatment, such as a method using only a rust preventive coating agent and an invention described in Patent Document 3, etc., coating is performed thereon. Two types of application methods are well known. The surface treatment agent used in the latter case is called a “coating primer”, but the coating primer generally has a low solid content and is applied under the same conditions as the anticorrosive coating agent used without coating the upper layer. However, when only the corrosion resistance is compared, the coating base material alone cannot exhibit sufficient rust prevention.

  Furthermore, since the surface treatment compositions described in Patent Documents 1, 3, and 4 contain an organic resin, the weather resistance of the surface treatment film is not sufficient.

  In addition, in the metal surface treatment method described in Patent Document 5, a water-dispersible silica such as a silane coupling agent, a water-dispersible silica, and a metal surface treatment agent containing a zirconium compound, a silane coupling agent, and the like, and The antirust property is exhibited only by applying an anticorrosive coating agent containing phosphate ions and the like, and further forming an upper coating film (see Patent Document 5, Examples). The agent alone may not exhibit sufficient rust prevention properties.

  The present invention has been made in view of the above problems, and is a chromium-free rust-proof coating agent having sufficient storage stability, which is sufficient for a zinc-based metal substrate only by a film formed thereby. An object of the present invention is to provide a rust preventive coating agent capable of imparting rust properties, and further to provide a rust preventive treatment method for a metal substrate using the rust preventive coating agent and a metal material obtained thereby. To do.

  The inventors of the present invention provide a rust-preventing coating agent containing a film-forming component, wherein the film-forming component comprises an epoxy group-containing silane coupling agent having a predetermined content, and a hydrolyzate and hydrolysis condensate thereof; In addition, according to the anticorrosive coating agent having two or more thiol groups and only a thiol compound having a predetermined content, the inventors have found that the above problems can be solved, and have completed the present invention. Specifically, the present invention provides the following.

  (1) A rust-proof coating agent containing a film-forming component, wherein the film-forming component is an epoxy group-containing silane coupling agent and an epoxy group-containing silane coupling agent of 10 g / L or more and 200 g / L or less. A rust-preventive coating agent comprising only a thiol compound having two or more thiol groups in one molecule of at least one selected from the group consisting of a hydrolyzate and a hydrolyzed condensate; and 10 g / L or more and 200 g / L or less.

  Here, the “film-forming component” refers to a solid component that causes a polymerization reaction such as condensation or polymerization when applied to a metal substrate and dried, and is a compound formed by a polymerization reaction of the film-forming component. Coats the surface of the metal substrate by bonding to the surface of the metal substrate with a chemical bond. Such a film-forming component generally refers to an organic resin, silica, zirconium compound, phosphoric acid compound, etc., but whether or not a specific component is classified as a film-forming component is determined by a specific embodiment of the invention. It is what In the present invention, the epoxy group-containing silane coupling agent and the thiol compound having two or more thiol groups in one molecule are classified as film-forming components.

  (2) The rust preventive coating agent according to (1), wherein the thiol compound is triazine thiol or a triazine thiol derivative.

  Here, the “triazine thiol derivative” refers to a compound having a triazine ring composed of three nitrogen atoms and three carbon atoms and having two or more thiol groups or groups derived therefrom. Further, the “triazine thiol derivative” may be a salt formed with a metal ion if necessary, and includes a compound in which a salt of the triazine thiol itself and the metal ion forms a salt.

  (3) The molar equivalent ratio of the epoxy group-containing silane coupling agent, the epoxy group contained in the hydrolyzate and hydrolysis condensate of the epoxy group-containing silane coupling agent, and the thiol group contained in the thiol compound is The anticorrosive coating agent according to (1) or (2), which is within a range of 1: 0.5 or more and 1: 6 or less.

  Here, "molar equivalent ratio" means the total amount of epoxy groups contained in the epoxy group-containing silane coupling agent, its hydrolyzate and hydrolysis condensate contained in the antirust coating agent, and the antirust coating agent. It refers to the molar conversion ratio (epoxy group: thiol group) with the total amount of thiol groups contained in the thiol compound contained.

  (4) The anticorrosive coating agent according to any one of (1) to (3), which does not contain silica; an organic resin other than the hydrolysis condensate of an epoxy group-containing silane coupling agent; a zirconium compound; and a phosphate compound.

  (5) A rust preventive coating agent according to any one of (1) to (4) is brought into contact with a metal substrate to produce a metal material having a rust preventive film formed by the rust preventive coating agent as an uppermost layer. Antirust treatment method for metal substrate.

  (6) The antirust treatment method according to (5), wherein the metal substrate is a zinc-based metal substrate.

  Here, the “zinc-based metal substrate” refers to a metal substrate having a surface made of zinc or a zinc alloy.

  (7) A metal material having, as a top layer, a rust preventive film formed on the metal base material by the rust preventive coating agent according to any one of (1) to (4).

  According to the present invention, the film-forming component contained in the anticorrosive coating agent is an epoxy group-containing silane coupling agent having a predetermined content, and its hydrolyzate and hydrolysis condensate; and two or more thiol groups Since it is only a thiol compound with a predetermined content, the storage stability of the anticorrosive coating agent is good. Further, the anticorrosive coating agent has an epoxy group-containing silane coupling agent having a predetermined content, and a hydrolyzate and hydrolysis condensate thereof; and two or more thiol groups, and a thiol compound having a predetermined content. Therefore, a strong film can be formed on the metal substrate, and a metal material having excellent rust prevention can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail.

<Rust-proof coating agent>
The anticorrosive coating agent of the present invention contains a film-forming component, and the film-forming component is selected from the group consisting of an epoxy group-containing silane coupling agent having a predetermined content, and a hydrolyzate and hydrolysis condensate thereof. At least one kind (hereinafter sometimes referred to as “epoxy group-containing silane coupling agent”); and a predetermined content of thiol compound having two or more thiol groups in one molecule (hereinafter referred to as “thiol compound”) May be mentioned).

[Film forming component]
Here, as described above, the “film-forming component” refers to a solid component that causes a polymerization reaction such as condensation or polymerization at the time of application to a metal substrate and drying. The solid component which coat | covers the surface of a metal base material, when the formed compound couple | bonds with the surface of a metal base material with a chemical bond. In the anticorrosive coating agent of the present invention, the component contained as a film-forming component has an epoxy group-containing silane coupling agent, its hydrolyzate and hydrolysis condensate, and two or more thiol groups in one molecule. It is only a thiol compound, and this alone exhibits sufficient rust prevention properties. Here, in the present invention, in order to improve the anticorrosive property of the anticorrosive coating agent, organic resin other than the hydrolysis condensate of silica and silane coupling agent, zirconium compound, phosphoric acid compound and the like other than the above film forming components Therefore, the storage stability of the rust preventive coating agent can be remarkably improved.

(Epoxy group-containing silane coupling agent)
As the epoxy group-containing silane coupling agent used in the anticorrosive coating agent of the present invention, conventionally known epoxy group-containing silane coupling agents used in the paint field and the like can be widely used. Specific examples of the epoxy group-containing silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycid. Xylpropylmethyldiethoxysilane, 3-glycidoxypropyldiethylethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 5,6 -Epoxy hexyl triethoxysilane etc. can be mentioned.

  A commercial item can be used for these silane coupling agents. Examples of such commercially available products include “KBM-403” (trade name, 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), “KBE-403” (trade name, 3-glycidoxypropyltriethoxy). Silane, manufactured by Shin-Etsu Chemical Co., Ltd.), "KBE-402" (trade name, 3-glycidoxypropylmethyldiethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), "KBM-303" (trade name, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane) and the like. These compounds may be used alone or in combination of two or more.

(Hydrolysis condensate of epoxy group-containing silane coupling agent)
The epoxy group-containing silane coupling agent is hydrolyzed in an aqueous solution to reveal a silanol group. Depending on the content of the epoxy group-containing silane coupling agent, the hydrolyzed epoxy group-containing silane coupling agent is Start self-condensation. Therefore, the epoxy group-containing silane coupling agent is considered to be a mixture of the epoxy group-containing silane coupling agent and its hydrolyzate and hydrolysis condensate according to the concentration at the time when it is added to the aqueous solution. It is done.

(Contents such as epoxy group-containing silane coupling agents)
The antirust coating agent of the present invention contains 10 g / L or more and 200 g / L or less of an epoxy group-containing silane coupling agent and the like. When the epoxy group-containing silane coupling agent or the like is less than 10 g / L, the film treated with the antirust coating agent does not have sufficient antirust properties and is formed using the antirust coating agent. When an overcoat film is formed on the upper layer of the film, there is a risk that the adhesion to the overcoat film of the film will be reduced. Moreover, when content, such as an epoxy group containing silane coupling agent, exceeds 200 g / L, the storage stability of an antirust coating agent falls and it may not be used as an antirust coating agent. The content of the epoxy group-containing silane coupling agent or the like is preferably 90 g / L or more and 170 g / L or less. In the present specification, the content of the epoxy group-containing silane coupling agent, etc. is the same as that of the epoxy group-containing silane cup before hydrolysis and condensation of the hydrolyzate and hydrolysis condensate of the epoxy group-containing silane coupling agent. It means the concentration calculated as being a ring agent.

(Thiol compound having two or more thiol groups in one molecule)
The antirust coating agent of the present invention contains a thiol compound having two or more thiol groups in one molecule. The thiol compound containing two or more thiol groups in one molecule is not particularly limited, but 1,2-ethanedithiol, 1,4-butanedithiol, di (2-mercaptoethyl) sulfide, ethylene Glycol dithioglycolate, ethylene glycol dithiopropionate, 1,4-butanediol dithioglycolate, di (2-mercaptoethyl) ether, 2-hydroxypropane-1,3-dithiol, 1,6-dimercaptohexane, Trithioglycerin, trimethylolpropane tris (thioglycolate), trimethylolpropane tris (thiopropionate), 2- (2'-mercaptoethylthio) -1,3-dimercaptopropane, pentaerythritol tetrakis (thioglyco) Rate), pentaerythrito Aliphatic tetrakis (thiopropionate), pentaerythritol tetramercaptan, tetrakis (2-mercaptoethylthiomethyl) methane, 5,5-bis (mercaptomethyl) -3,7-dithia-1,9-nonanedithiol, etc. Thiol compounds; and 1,4-benzenedithiol, 1,3-xylylenedithiol, 1,4-bis (2-mercaptoethyl) benzene, 3,4-dimercaptotoluene, bis (4-mercaptophenyl) sulfide, 4 One of the thiol groups in -tert-butyl-1,2-benzenethiol, 1,5-dimercaptonaphthalene, 2,7-dimercaptonaphthalene, triazinethiol is substituted with a functional group such as an alkylamino group or an alkoxy group Triazine thiol derivatives such as 2-dibutylamino -4,6-dimercaptotriazine), triazine thiol derivatives in which triazine thiol is bonded to a polymer compound such as a silane oligomer (for example, a silane coupling agent having a triazine thiol structure as a functional group in the molecule is a silanol group Examples thereof include a compound oligomerized by dehydration condensation (molecular weight of about 20,000 to 30,000, hereinafter referred to as “triazine thiol-modified silane oligomer”), and aromatic thiol compounds such as triazine thiol. These thiol compounds may form a salt as necessary, and may be used alone or in combination of two or more.

  Among these, triazine thiol, triazine thiol derivative (triazine thiol salt, 2-butylamino-4,6-dimercaptotriazine, triazine thiol-modified silane oligomer (presumed thiol equivalent 3000; thiol equivalent is a thiol group in a molecule) It means the molecular weight per one) and the like. In addition, among thiol compounds having two or more thiol groups in one molecule, a stronger film is formed and rust prevention can be improved, so three or more thiol groups are contained in one molecule. Compounds are preferred, and triazine thiol, salts of triazine thiol, and triazine thiol-modified oligomers are particularly preferred.

(Content of thiol compound)
The antirust coating agent of the present invention contains 10 g / L or more and 200 g / L or less of a thiol compound having two or more thiol groups in one molecule. When the content of the thiol compound having two or more thiol groups in one molecule is less than 10 g / L, the film treated with the rust preventive coating agent does not have sufficient rust preventive properties, When the top coat film is formed on the upper layer of the film formed using the rust coating agent, the adhesion to the top coat film of the film may be lowered. In addition, when the content of the thiol compound having two or more thiol groups in one molecule exceeds 200 g / L, the storage stability of the rust-preventing coating agent is lowered and may not be used as a rust-preventing coating agent. . The content of the thiol compound having two or more thiol groups in one molecule is preferably 30 g / L or more and 90 g / L or less.

  In addition, although the antirust coating agent of this invention has an effect by containing the said content of the thiol compound which has 2 or more of thiol groups in 1 molecule, it is 3 or more of thiol groups in 1 molecule. By containing the thiol compound having the above content, a more preferable effect is obtained. That is, in the anticorrosive coating agent of the present invention, it is preferable to contain 10 g / L or more and 200 g / L or less of a thiol compound containing 3 or more thiol compounds in one molecule, and 20 g / L or more and 60 g / L or less. More preferably.

(Mole equivalent ratio of epoxy group possessed by epoxy group-containing silane coupling agent and the like and thiol group possessed by thiol compound)
The molar equivalent ratio of the epoxy group contained in the epoxy group-containing silane coupling agent contained in the anticorrosive coating agent of the present invention and the thiol group contained in a thiol compound having two or more thiol groups in one molecule (epoxy group: The thiol group is preferably from 1: 0.5 to 1: 6. By setting the molar equivalent ratio within the above range, both the content of the epoxy group-containing silane coupling agent and the thiol compound having two or more thiol groups in one molecule are maintained in a suitable range. Therefore, the rust prevention property which the film processed by the rust prevention coating agent has is improved. The molar equivalent ratio is more preferably 1: 0.6 or more and 1: 1.5 or less.

(Total content of epoxy group-containing silane coupling agent and thiol compound)
It is preferable that the antirust coating agent of this invention contains 130 g / L or more of solid content. When the solid content concentration in the antirust coating agent is within the above range, the antirust property of the film formed from the antirust coating agent can be further improved. Examples of the solid content include the above-described epoxy group-containing silane coupling agent and thiol compounds having two or more thiol groups in one molecule.

(Other film forming components)
The anticorrosive coating agent of the present invention contains a film forming component, and the film forming component is only an epoxy group-containing silane coupling agent or the like and a thiol compound. Thus, the storage stability of a rust preventive coating agent can be improved by the rust preventive coating agent of this invention containing only an epoxy group containing silane coupling agent etc. and a thiol compound as a film formation component. Examples of film forming components other than epoxy group-containing silane coupling agents and thiol compounds include silica; organic resins other than hydrolysis condensates of epoxy group-containing silane coupling agents; zirconium compounds; and phosphate compounds. can do. The phosphate compound here is a compound capable of generating at least one of phosphate ion, phosphite ion and hypophosphite ion in a state dissolved in water, and / or a phosphate group, It means a compound having a phosphoric acid group and a hypophosphorous acid group.

  In addition, although it describes below about the mechanism in which the antirust coating agent of this invention exhibits the outstanding rust prevention property, about the said mechanism, it is based on an inventor's estimation of this invention, and does not limit the scope of this invention at all. Absent. That is, when a film is formed on the metal substrate from the anticorrosive coating agent of the present invention, the thiol group of the thiol compound having two or more thiol groups in one molecule is an epoxy group-containing silane coupling agent or the like. Nucleophilic attack is carried out on the epoxy group possessed, and these compounds are bonded in such a way that the epoxy group is ring-opened. In addition, silanol groups derived from epoxy group-containing silane coupling agents undergo a self-condensation reaction, and some silanol groups and thiol groups are strongly bonded to the metal atoms constituting the metal substrate, resulting in a network structure. It is presumed that excellent rust preventive properties are exhibited according to the binding force of silanol groups and thiol groups contained in these films to the surface of the metal substrate.

  Here, in the present invention, since the content of the epoxy group-containing silane coupling agent and the like and the content of the thiol compound having two or more thiol groups in one molecule are limited to those within a predetermined range, It is presumed that the formation of a film having a structure becomes easier, and the rust prevention property of the film formed by the rust prevention coating agent becomes more suitable.

  In general, a compound having a plurality of reactive functional groups and a compound having a single reactive functional group tend to be more reactive with a compound having a plurality of reactive functional groups. When a thiol compound having two or more groups is used, it is presumed that the binding force to the metal atom constituting the metal substrate becomes stronger. In addition, when the thiol compound has a plurality of reactive functional groups, it is presumed that it is easier to form a film having a network structure and a dense film can be formed.

[Additives other than film-forming components]
The rust-proof coating agent of the present invention may further contain other additives. Examples of such additives include surfactants and solvents.

  Here, the solvent is used to improve the film-forming property due to the solid content in the anti-corrosion coating agent and form a more uniform and smooth film, and is particularly limited as long as it is generally used in the paint field. Is not to be done. Specific examples include water, alcohol solvents, ester solvents, and ether solvents.

<Rust prevention treatment method for metal substrate>
The rust preventive treatment method of the metal base material of the present invention is to bring a metal base material into contact with the rust preventive coating agent of the present invention and to have a rust preventive film formed by the rust preventive coating agent as the uppermost layer. Is the method. Since the rust preventive treatment method of the metal substrate of the present invention is performed using the rust preventive coating agent of the present invention, a rust preventive film excellent in rust resistance can be formed on the metal substrate. The rust preventive film formed by the conventional rust preventive coating agent is not necessarily sufficient in rust preventive property only by the rust preventive film. On the other hand, in the rust preventive treatment method of the metal substrate of the present invention, since the rust preventive film has excellent rust preventive properties, it is not necessary to form a coating film on the upper layer (that is, the rust preventive film). Even if it exists as the uppermost layer), a metal material having a sufficient antirust property can be formed alone. In addition, since it is not necessary to form a coating film on the upper layer, the rust prevention film formed by the rust prevention treatment method of the metal substrate of the present invention is a rust prevention film formed by a conventional rust prevention coating agent, Compared with a composite coating film with an upper coating film, a thin film can exhibit a sufficient rust prevention effect.

[Metal base material]
As a metal base material used as the application object of the rust prevention processing method of the metal base material of this invention, it is not specifically limited, An iron-type metal base material, an aluminum-type metal base material, a zinc-type metal base material, a tin type A metal base material etc. can be mentioned. Specifically, as an iron-based metal substrate, a cold-rolled steel plate, a hot-rolled steel plate, a mild steel plate, and a high-tensile steel plate are used, and as an aluminum-based metal substrate, A-1050 material, A-1100 material, A- 1N30 material, A-3004 material, A-3105 material, A-5021 material, A-5052 material, A-5182 material, and A-8079 material, zinc or zinc-aluminum alloy as the zinc-based metal substrate As a tin-based metal substrate, a galvanized steel sheet made of zinc alloy selected from zinc-nickel alloy, zinc-titanium alloy, zinc-magnesium alloy, and zinc-manganese alloy, and electrogalvanized steel sheet, tin, tin Mention may be made of tin-plated steel sheets made of alloys or tin alloys such as tin or tin-zinc alloys. Among these, it is preferable to use a zinc-based metal substrate.

  The reason why a zinc-based metal substrate is preferable as the metal substrate is not necessarily clear, but is presumed to be as follows. That is, it is considered that the thiol group of the thiol compound having two or more thiol groups in one molecule can react with the zinc surface to form zinc sulfide. Zinc sulfide is one of the most stable compounds among the zinc compounds, as is clear from the fact that zinc sulfide exists in nature as sphalerite. In other words, since the bond between zinc and sulfur is generally strong, a thiol compound having two or more thiol groups in one molecule acts on a metal surface made of zinc or a zinc alloy, thereby preventing rust. This is considered to improve the performance.

[Degreasing treatment]
In the rust preventive treatment method of the metal substrate of the present invention, it is preferable to degrease the metal substrate as necessary before applying the rust preventive coating agent of the present invention to the metal substrate. When performing a degreasing process, the conventionally well-known process by alkali degreasing and solvent degreasing can be employ | adopted, and it is preferable to wash and dry a metal base material after a degreasing process. In addition, after the degreasing treatment, prior to carrying out the rust preventive treatment method for a metal substrate of the present invention, alkali washing or acid washing may be performed.

[Method of applying anti-corrosion coating agent]
In applying the rust preventive treatment method for a metal substrate of the present invention, the rust preventive coating agent of the present invention is brought into contact with the metal substrate. The method for bringing the rust preventive coating agent of the present invention into contact with a metal substrate is not particularly limited, and generally used roll coat, shower coat, spray coat, dipping, brush coating, etc. can be employed. . Moreover, when making the rust preventive coating agent of this invention contact a metal base material, it is preferable to perform heat drying next. What is necessary is just to dry so that the temperature of a metal base material may be 80 degreeC or more in the case of heat drying.

  In the rust preventive treatment method of the metal substrate of the present invention, in the metal material obtained by this, the film obtained by the rust preventive coating agent of the present invention is a major feature, After forming the rust preventive film using the rust preventive coating agent of the present invention, it does not prevent further formation of the upper coating film, and has an upper coating film on the upper layer of the rust preventive film as necessary. Also good.

<Metal material>
The metal material of the present invention has a rust preventive film formed on the metal substrate by the rust preventive coating agent of the present invention as the uppermost layer. That is, since the rust preventive film formed by the rust preventive coating agent of the present invention alone has sufficient rust preventive property, the rust preventive film as a top layer on the metal substrate (that is, as a film constituting the surface layer). Even when a film is formed, a metal material having sufficient antirust property can be provided.

The rust preventive film formed on the metal material of the present invention preferably has a film amount of 0.4 g / m ² or more and 0.7 g / m ² or less. When the amount of the film is within the above range, the rust preventive property of the rust preventive film formed on the metal material can be made suitable. When the amount of the film is not less than the above lower limit value, the rust preventive film can exhibit sufficient rust preventive properties. When the coating amount is less than the above upper limit value, it is possible to prevent economic waste due to saturation of the effect by adjusting the coating amount, and at the time of processing the steel sheet due to the decrease in conductivity of the rust prevention coating. The influence on work can be prevented.

  The metal material of the present invention is characterized in that the film obtained by the rust preventive coating agent of the present invention is present as the uppermost layer, but the rust preventive film using the rust preventive coating agent of the present invention. This is not to prevent the formation of an upper coating film after the formation of, but may be a metal material having an upper coating film formed on the rust preventive coating as necessary.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, this invention is not limited to the Example shown below at all.

<Example 1>
11.7 parts by mass of 3-glycidoxypropyltrimethoxysilane (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) which is an epoxy group-containing silane coupling agent in water, and a thiol group in one molecule 1.3 parts by mass of 2,4,6-trimercapto-s-triazine monosodium salt, which is a thiol compound having three, was added to prepare a rust-proof coating agent with a total amount of 100 parts by mass. The solid content concentration of the anticorrosive coating agent was 130 g / L, and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group) was 1: 0.4.

<Examples 2 and 3>
Instead of 3-glycidoxypropyltrimethoxysilane as an epoxy group-containing silane coupling agent, 3-glycidoxypropyltriethoxysilane (trade name “KBE-403”, manufactured by Shin-Etsu Chemical Co., Ltd .; Example 2) or Using 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (trade name “KBM-303”, manufactured by Shin-Etsu Chemical Co., Ltd .; Example 3), its content and three thiol groups in one molecule The rust preventive coating agent was applied in the same manner as in Example 1 except that the content of 2,4,6-trimercapto-s-triazine monosodium salt, which is a thiol compound, was changed as described in Table 1. Prepared. Table 1 also shows the solid content concentration of the anticorrosive coating agent and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group).

<Examples 4 to 10>
Content of 3-glycidoxypropyltrimethoxysilane, which is an epoxy group-containing silane coupling agent, and 2,4,6-trimercapto-s-triazine mono, which is a thiol compound having three thiol groups in one molecule A rust-proof coating agent was prepared in the same manner as in Example 1 except that the content of the sodium salt was changed as described in Table 1. Table 1 also shows the solid content concentration of the anticorrosive coating agent and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group).

<Examples 11 and 12>
Triazine thiol-modified silane oligomer (presumed thiol equivalent 3000; Example 11) as a thiol compound having three or more thiol groups in one molecule, or 2-dibutylamino as a thiol compound having two thiol groups in one molecule Using -4,6-dimercapto-s-triazine (Example 12), the content of 3-glycidoxypropyltrimethoxysilane, which is an epoxy group-containing silane coupling agent, and two thiol groups in one molecule A rust-proof coating agent was prepared in the same manner as in Example 1 except that the content of the thiol compound was changed as described in Table 1. Table 1 also shows the solid content concentration of the anticorrosive coating agent and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group). The thiol equivalent means the molecular weight per thiol group in the molecule.

<Examples 13 to 24>
Content of 3-glycidoxypropyltrimethoxysilane, which is an epoxy group-containing silane coupling agent, and 2,4,6-trimercapto-s-triazine mono, which is a thiol compound having three thiol groups in one molecule A rust-proof coating agent was prepared in the same manner as in Example 1 except that the content of the sodium salt was changed as described in Table 1. Table 1 also shows the solid content concentration of the anticorrosive coating agent and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group).

<Comparative Examples 1 to 5>
Content of 3-glycidoxypropyltrimethoxysilane, which is an epoxy group-containing silane coupling agent, and 2,4,6-trimercapto-s-triazine mono, which is a thiol compound having three thiol groups in one molecule Table 1 shows the contents of sodium salt (Comparative Examples 1, 2 and 5), or triazine thiol-modified silane oligomer having 3 or more thiol groups in one molecule (estimated thiol equivalent 3000; Comparative Examples 3 and 4). A rust-proof coating agent was prepared in the same manner as in Example 1 except that the changes were made as described. Table 1 also shows the solid content concentration of the anticorrosive coating agent and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group). In Comparative Examples 1 to 5, the content of the epoxy group-containing silane coupling agent and / or the content of the thiol compound having two or more thiol groups in one molecule is outside the predetermined range of the present application. It has become.

<Comparative Example 6>
1,2.9 parts by mass of 3-glycidoxypropyltrimethoxysilane which is an epoxy group-containing silane coupling agent in water, 2,4,6-trimercapto which is a thiol compound having three thiol groups in one molecule -S-triazine monosodium salt (2.1 parts by mass) and silica particles “Snowtex N” (manufactured by Nissan Chemical Industries, Ltd.) (4.6 parts by mass) were added to prepare a rust preventive coating agent with a total amount of 100 parts by mass. did. The solid content concentration of this anticorrosive coating agent was 196 g / L, and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group) was 1: 0.6.

<Comparative Example 7>
7.4 parts by mass of epoxy group-containing silane coupling agent 3-glycidoxypropyltrimethoxysilane in water, 2,4,6-trimercapto which is a thiol compound having three thiol groups in one molecule 1.6 parts by mass of -s-triazine monosodium salt, 5.0 parts by mass of zirconium compound "Zircozol AC-7" (zirconium carbonate, manufactured by Daiichi Rare Element Co., Ltd.), and the total amount as 100 parts by mass A rust-proof coating agent was prepared. The solid content concentration of this anticorrosive coating agent was 140 g / L, and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group) was 1: 0.75.

<Comparative Example 8>
12.4 parts by mass of 3-glycidoxypropyltrimethoxysilane which is an epoxy group-containing silane coupling agent and 2,4,6-trimercapto which is a thiol compound having three thiol groups in one molecule in water 2.6 parts by mass of -s-triazine monosodium salt, 5.0 parts by mass of “Jurimer AC-10L” (polyacrylic acid resin, manufactured by Toagosei Co., Ltd.) which is a water-soluble resin, and the total amount as 100 parts by mass A rust-proof coating agent was prepared. The solid content concentration of the anticorrosive coating agent was 200 g / L, and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group) was 1: 0.75.

<Comparative Example 9>
11.9 parts by mass of 3-glycidoxypropyltrimethoxysilane which is an epoxy group-containing silane coupling agent in water, 2,4,6-trimercapto which is a thiol compound having three thiol groups in one molecule A rust-preventing coating agent was prepared by adding 3.1 parts by mass of -s-triazine monosodium salt and 5.0 parts by mass of monoammonium dihydrogen phosphate as a phosphoric acid compound to make the total amount 100 parts by mass. The solid content concentration of this rust preventive coating agent was 200 g / L, and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group) was 1: 0.94.

<Comparative Example 10>
A thiol compound having 12.0 parts by mass of vinyltrimethoxysilane (trade name “KBM-1003”, manufactured by Shin-Etsu Chemical Co., Ltd.) as a vinyl group-containing silane coupling agent in water and three thiol groups in one molecule. 2,4,6-trimercapto-s-triazine monosodium salt was added in an amount of 3.0 parts by mass to prepare a rust-proof coating agent with a total amount of 100 parts by mass. The solid content concentration of this rust-proof coating agent was 150 g / L.

<Comparative Example 11>
13.2 parts by mass of 3-glycidoxypropyltrimethoxysilane which is an epoxy group-containing silane coupling agent in water and 6.8 L-cysteine which is a thiol compound having only one thiol group in one molecule A rust preventive coating agent was prepared by adding 100 parts by mass of the total amount. The solid content concentration of this rust preventive coating agent was 200 g / L, and the molar equivalent ratio of epoxy group to thiol group (epoxy group: thiol group) was 1: 1.

<Evaluation>
[Storage stability]
After storing the anticorrosive coating agents of Examples 1 to 24 and Comparative Examples 1 to 11 in a thermostatic device at 40 ° C. for 3 months, the presence or absence of gelation and / or precipitation in the anticorrosive coating agent was visually observed. Evaluation was made based on the following criteria. The test was accepted with an evaluation ○.
○: Neither gelation nor solid sedimentation is observed.
X: Gelation or sedimentation of solid content is observed.

[Primary rust prevention]
(Preparation of test plate for rust prevention test)
A commercially available galvanized steel sheet was spray degreased at 60 ° C. for 2 minutes using “Surf Cleaner 155” (alkaline cleaner, manufactured by Nippon Paint Co., Ltd.), washed with water, and dried at 80 ° C. The rust preventive coating agents of Examples 1 to 24 and Comparative Examples 1 to 11 were applied with a bar coater so that the coating amount after drying was 0.2 g / m ² to 0.7 g / m ² . A test plate was produced by drying at a material arrival temperature of 80 ° C.

  As for the galvanized steel sheet, in Examples 1 to 22 and Comparative Examples 1 to 11, a galvalume steel sheet (Zn45% -Al55% hot dip galvanized steel sheet), in Example 23, an electrogalvanized steel sheet, Example 24 Then, hot dip galvanized steel sheet was used.

(Salt spray test (SST))
After sealing the end face part and back face part of the test plate prepared in the above section (Preparation of test plate for rust prevention test), a salt spray test in which 5% saline is sprayed on the coated surface at 35 ° C. for up to 240 hours The degree of occurrence of white rust was visually observed and evaluated based on the following criteria. Evaluation was performed for both the flat portion and the Erichsen 7 mm processed portion (extruded portion), and the evaluation was evaluated as “good” or higher.
◎: White rust generation area less than 5% of the whole ○: White rust generation area of 5% or more and less than 25% △: White rust generation area of 25% or more and less than 50% of the whole ×: White rust generation area 50% or more of-: Not implemented (due to poor storage stability)

[Top coat adhesion]
(Preparation of test plate for topcoat adhesion test)
For each test plate produced in (Preparation of test plate for rust prevention test) in [Primary rust prevention] above, use “super rack 100” (acrylic melamine paint, manufactured by Nippon Paint Co., Ltd.) using a bar coater. After coating so that the dry film thickness was 20 mm, it was dried at 150 ° C. for 20 minutes to prepare a test plate for a top coat adhesion test.

(Primary adhesion test)
A 1 mm-wide grid is cut into the test plate prepared in the above section (Preparation of topcoat adhesion test test plate), the cut portion is extruded to 7 mm with Erichsen, and adhesive tape is applied to the processed portion. It peeled after attaching. The peeling state of the top coat film was evaluated based on the following criteria. Evaluation was passed with more than ○.
◎: No peeling ○: Coating film remaining rate is 90% or more and less than 100% Δ: Coating film remaining rate is 50% or more and less than 90% ×: Coating film remaining rate is less than 50%

  The above evaluation results are shown in Table 2.

  From Table 2, the rust preventive coating agent of the present invention is a rust preventive coating agent using a silane coupling agent having no epoxy group or a rust preventive agent using a thiol compound having only one thiol group in one molecule. It can be seen that both storage stability and rust resistance are superior compared to the coating agent. In addition, the epoxy group-containing silane coupling agent and the content of the thiol compound are both storage stability and rust preventive compared to the anticorrosive coating agent described in the comparative example, which is not within the scope of the present invention. It turns out that it is excellent. In addition, the anticorrosive coating agent of the present invention containing only an epoxy group-containing silane coupling agent or the like and a thiol compound as a film forming component is used for other film forming components (silica particles, zirconium compounds, water-soluble resins, phosphate compounds). It can be seen that the storage stability is excellent as compared with the anticorrosive coating agent described in the comparative example containing. As mentioned above, according to this invention, the antirust coating agent excellent in both the storage stability and the antirust property can be obtained.

  According to the present invention, the film-forming component contained in the anticorrosive coating agent is an epoxy group-containing silane coupling agent having a predetermined content, and its hydrolyzate and hydrolysis condensate; and two or more thiol groups Since it is only a thiol compound with a predetermined content, the storage stability of the anticorrosive coating agent is good. Further, the anticorrosive coating agent has an epoxy group-containing silane coupling agent having a predetermined content, and a hydrolyzate and hydrolysis condensate thereof; and two or more thiol groups, and a thiol compound having a predetermined content. Therefore, a strong film can be formed on the metal substrate, and a metal material having excellent rust prevention can be obtained.

Claims (7)

A rust-proof coating agent containing a film-forming component,
The film-forming component is at least one selected from the group consisting of 10 g / L or more and 200 g / L or less of an epoxy group-containing silane coupling agent, and a hydrolyzate and hydrolysis condensate of an epoxy group-containing silane coupling agent; Moreover, the antirust coating agent which is only a thiol compound which has 2 or more of thiol groups in 1 molecule of 10 g / L or more and 200 g / L or less.   The rust preventive coating agent according to claim 1, wherein the thiol compound is triazine thiol or a triazine thiol derivative.   The molar equivalent ratio of the epoxy group-containing silane coupling agent and the epoxy group of the hydrolyzate and hydrolysis condensate of the epoxy group-containing silane coupling agent to the thiol group of the thiol compound is 1: 0. The anticorrosive coating agent according to claim 1 or 2, wherein the antirust coating agent is within a range of from 5 to 1: 6.   The rust preventive coating agent according to any one of claims 1 to 3, which does not contain silica; an organic resin other than a hydrolysis condensate of an epoxy group-containing silane coupling agent; a zirconium compound; and a phosphate compound.   An antirust coating agent according to any one of claims 1 to 4 is brought into contact with a metal substrate to produce a metal material having an antirust film formed by the antirust coating agent as an uppermost layer. Rust treatment method.   The rust prevention method according to claim 5, wherein the metal substrate is a zinc-based metal substrate.   A metal material having, as an uppermost layer, a rust preventive film formed on the metal substrate by the rust preventive coating agent according to any one of claims 1 to 4.