JP2024055021A - Surface treatment agent for carbon steel material, carbon steel material having a surface treatment film and its manufacturing method - Google Patents

Abstract

[Problem] To provide a surface treatment agent capable of forming a surface treatment film having excellent resistance to electrolytic corrosion. [Solution] To solve the problem, a surface treatment agent for carbon steel materials is provided, which contains a silicone resin (A), a titanium compound (B), a barium compound (C), an aromatic hydrocarbon solvent (D), and an alkoxysilane (E) having an amino group, and in which (I) the ratio (BM/AM) of the mass (AM) of the silicone resin (A) to the mass (BM) of the compound (B) is in the range of 0.05 to 3.12, (II) the ratio (CM/AM) of the mass (AM) of the silicone resin (A) to the mass (CM) of the compound (C) is in the range of 0.02 to 0.55, and (III) the ratio (EM/AM) of the mass (AM) of the silicone resin (A) to the mass (EM) of the compound (E) is in the range of 0.01 to 0.43. [Selected Figure] None

Description

The present invention relates to a surface treatment agent that can be suitably used for carbon steel materials of machine components used in products such as automobiles, home appliances, office automation equipment, and medical equipment, a method for manufacturing carbon steel materials having a surface treatment coating using the surface treatment agent, and a carbon steel material having a surface treatment coating obtained by the manufacturing method.

In industrial products such as automobiles, home appliances, office automation equipment, and medical equipment, metal materials are used in the machine components that make up the products. Since these industrial products are used in various environments, various performances are required for the metal materials used in these industrial products. Therefore, in recent years, in order to impart various performances to metal materials, techniques have been developed for providing surface treatment coatings with various performances on or on the surface of metal materials. For example, Patent Document 1 discloses a technique in which a metal material surface treatment composition in which a predetermined amount of a predetermined phosphoric acid compound, a fluoro acid having a predetermined element such as titanium or zirconium, a silane coupling agent having at least one active hydrogen-containing amino group, and a silane coupling agent having at least one epoxy group are mixed and dissolved or dispersed is applied to a metal surface, and then dried to form a predetermined coating.

JP 2006-213958 A

In recent years, there has been a demand for the development of technology capable of forming a surface treatment coating with excellent resistance to electrolytic corrosion for carbon steel materials used in machine components. Therefore, the present invention aims to provide a surface treatment agent capable of forming a surface treatment coating with excellent resistance to electrolytic corrosion, a method for manufacturing a carbon steel material having a surface treatment coating using the surface treatment agent, and a carbon steel material having a surface treatment coating obtained by the manufacturing method.

As a result of intensive research into solving the above problems, the inventors discovered that a surface treatment coating with excellent resistance to electrolytic corrosion can be formed on or above the surface of a carbon steel material by using a surface treatment agent containing a silicone resin, a compound containing a specified metal element, and a specified amount of an aromatic hydrocarbon solvent, and thus completed the present invention.

That is, the present invention provides
[1] A silicone resin (A), a titanium compound (B), a barium compound (C), an aromatic hydrocarbon solvent (D), and an alkoxysilane having an amino group (E),
(I) the ratio (B _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (B _M ) of the compound (B) is within the range of 0.05 to 3.12,
(II) the ratio (C _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (C _M ) of the compound (C) is within the range of 0.02 or more and 0.55 or less;
(III) A surface treatment agent for carbon steel materials, in which the ratio (E _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (E _M ) of the compound (E) is within the range of 0.01 or more and 0.43 or less;
[2] A method for producing a carbon steel material having a surface treatment coating, comprising a first step of contacting the surface treatment agent described in [1] above with a surface or on a surface of a carbon steel material, and a second step of drying the surface treatment agent contacted with the carbon steel material to form a surface treatment coating;
[3] The manufacturing method according to the above [2], further comprising a base coating formation step of contacting a surface or a surface of the carbon steel material with a silane coupling agent having an amino group, a polymer of the silane coupling agent, a copolymer with the polymer, or a base treatment agent containing phosphoric acid to form a base coating before the first step;
[4] A carbon steel material having a surface treatment coating, obtained by the manufacturing method according to the above [2] or [3], wherein the film thickness of the surface treatment coating is within the range of 3 μm or more and 100 μm or less;
[5] A surface treatment coating is provided on or at the surface of a carbon steel material,
the surface treatment coating contains a silicone resin (A), a titanium compound (B), a barium compound (C), and a polymer derived from an alkoxysilane having an amino group (E);
(I) the ratio (B _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (B _M ) of the compound (B) is within the range of 0.05 to 3.12,
(II) A carbon steel material having a surface treatment coating, in which the ratio ( _CM / _AM ) of the mass ( _AM ) of the silicone resin (A) to the mass ( _CM ) of the compound (C) is within the range of 0.02 or more and 0.55 or less;
[6] A base coating is provided between the carbon steel material and the surface treatment coating,
A carbon steel material having a surface treatment coating according to the above-mentioned [5], wherein the undercoat coating contains at least one selected from the group consisting of a silane coupling agent having an amino group, a polymer of the silane coupling agent, a copolymer of the polymer and phosphoric acid;
[7] A carbon steel material having a surface treatment coating according to the above [5] or [6], wherein the thickness of the surface treatment coating is within the range of 3 μm or more and 100 μm or less;
[8] A high-carbon steel material having a surface treatment coating according to any one of [5] to [7] above, wherein the carbon steel material is a high-carbon steel containing 0.95 mass% or more of carbon;
And so on.

The present invention provides a surface treatment agent capable of forming a surface treatment coating with excellent resistance to electrolytic corrosion, a method for producing a carbon steel material having a surface treatment coating using the surface treatment agent, and a carbon steel material having a surface treatment coating obtained by the method.

The surface treatment agent, the carbon steel material having a surface treatment film, and the method for producing the same according to the present invention will be described below.
(Surface treatment agent)
The surface treatment agent according to the present embodiment contains a silicone resin (A), a titanium compound (B), a barium compound (C), an aromatic hydrocarbon solvent (D), and an alkoxysilane (E) having an amino group. By using this surface treatment agent, a surface treatment film having excellent resistance to electrolytic corrosion (particularly resistance to electrolytic corrosion under high temperature environment) can be formed on a carbon steel material. Here, high temperature means at least 100°C or higher, preferably 150°C or higher, and more preferably 200°C or higher. Thus, since the surface treatment agent according to the present embodiment can form a surface treatment film having excellent resistance to electrolytic corrosion, the surface treatment agent according to the present embodiment is useful as an agent for forming an electrolytic corrosion-resistant film. In addition, the surface treatment film having excellent resistance to electrolytic corrosion is useful for carbon steel materials and the like used in machine element members constituting industrial products such as automobiles, home appliances, office automation equipment, and medical equipment.

<Silicone resin (A)>
The silicone resin (A) is not particularly limited as long as it has a plurality of siloxane bonds and has an organopolysiloxane structure in which an organic group is bonded to silicon (Si), but is preferably an organopolysiloxane structure having at least two organic groups bonded to Si in one molecule. The position at which the organic group is bonded is not particularly limited, and it may be bonded to the main chain, side chain, or end. The silicone resin (A) may be a homopolymer having the above organopolysiloxane structure, a mixture of a homopolymer having the above organopolysiloxane structure and a homopolymer having a polysiloxane structure, or a copolymer (block copolymer or graft polymer) having the above organopolysiloxane structure and a polysiloxane structure. The silicone resin (A) may be an addition type or a condensation type. Furthermore, the silicone resin (A) may be any of a heat curing type, a room temperature curing type (RVT), and a UV curing type.

The organic group bonded to Si in the organopolysiloxane structure may be, for example, a saturated hydrocarbon group, an unsaturated hydrocarbon group, a halogenated alkyl group, an epoxycyclohexyl group, etc., but is not limited thereto. The saturated hydrocarbon group may be, for example, a linear or branched alkyl group, a cycloalkyl group, etc., but is not limited thereto. The unsaturated hydrocarbon group may be, for example, a linear or branched alkenyl group, a cycloalkenyl group, a cycloalkenylalkyl group, an aryl group, etc., but is not limited thereto. The organic group bonded to Si is preferably an unsaturated hydrocarbon group, more preferably an alkenyl group, and particularly preferably a vinyl group or a hexenyl group.

Examples of halogenated alkyl groups include chloromethyl, 3-chloropropyl, 1-chloro-2-methylpropyl, and 3,3,3-trifluoropropyl groups. Examples of alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. Examples of cycloalkyl groups include cyclopentyl and cyclohexyl groups. Examples of linear or branched alkenyl groups include vinyl, 1-propenyl, aryl, isopropenyl, 1-butenyl, 2-butenyl, pentenyl, and hexenyl groups. Examples of cycloalkenyl groups include cyclopentenyl and cyclohexenyl groups. Examples of cycloalkenylalkyl groups include cyclopentenylethyl, cyclohexenylethyl, and cyclohexenylpropyl groups. Examples of aryl groups include phenyl groups.

The polysiloxane structure is not particularly limited as long as it is different from the above-mentioned organopolysiloxane structure, and examples thereof include a polysiloxane structure having at least two hydrogen atoms bonded to Si in one molecule, and a polysiloxane structure having at least two alkoxy groups bonded to Si in one molecule. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The alkoxy group may be linear or branched.

The above-mentioned silicone resins may be used alone or in combination in the preparation of the surface treatment agent. One preferred embodiment of the silicone resin (A) is a mixture of a homopolymer having an organopolysiloxane structure having at least two unsaturated hydrocarbon groups bonded to Si in one molecule, and a homopolymer having a polysiloxane structure having at least two hydrogen atoms bonded to Si in one molecule.

Examples of homopolymers having an organopolysiloxane structure having at least two or more unsaturated hydrocarbon groups bonded to Si per molecule include dimethylpolysiloxane having dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylphenylsiloxane copolymer having dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylvinylsiloxane copolymer having dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylvinylsiloxane copolymer having trimethylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane terpolymer having trimethylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylvinylsiloxane copolymer having silanol groups at both molecular chain terminals, and methylvinylpolysiloxane having silanol groups at both molecular chain terminals. Other examples include polymers in which some of the methyl groups of various polymers, copolymers, and terpolymers have been substituted with alkyl groups other than methyl groups, such as ethyl groups, propyl groups, etc., or halogenated alkyl groups, such as 3,3,3-trifluoropropyl groups, 3,3,3-trichloropropyl groups, etc. A mixture of two or more selected from these polymers, copolymers, and terpolymers may be used to prepare the surface treatment agent.

Examples of monopolymers having a polysiloxane structure with at least two hydrogen atoms bonded to Si in each molecule include, but are not limited to, organohydrogenpolysiloxanes having at least two SiH groups in which a hydrogen atom is bonded to Si in each molecule, repeating diorganosiloxane structures as the main chain, and linear, cyclic, branched, or three-dimensional network structures in which both ends of the molecular chain are blocked with triorganosiloxy groups. More specifically, examples of the polymers include methylhydrogenpolysiloxane having trimethylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylhydrogensiloxane copolymer having trimethylsiloxy groups at both ends of the molecular chain, methylhydrogenpolysiloxane having silanol groups at both ends of the molecular chain, dimethylsiloxane-methylhydrogensiloxane copolymer having silanol groups at both ends of the molecular chain, dimethylpolysiloxane having dimethylhydrogensiloxy groups at both ends of the molecular chain, methylhydrogenpolysiloxane having dimethylhydrogensiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylhydrogensiloxane copolymer having dimethylhydrogensiloxy groups at both ends of the molecular chain, etc. A mixture of two or more selected from these polymers and copolymers may be used to prepare the surface treatment agent.

The weight average molecular weight of the silicone resin (A) is not particularly limited, but is usually in the range of 6,000 to 45,000, and preferably in the range of 6,500 to 40,000. The weight average molecular weight is measured by GPC (gel permeation column chromatography) and converted into polystyrene.

<Compound (B)>
Compound (B) is not particularly limited as long as it contains titanium as an element.Examples of the compound containing titanium include titanyl sulfate, titanyl nitrate, titanium nitrate, titanyl chloride, titanium chloride, titaniasol, titanium oxide, potassium oxalate titanate, titanium lactate, titanium tetraisopropoxide, titanium acetylacetonate, diisopropyltitanium bis(acetylacetonate), and titanium diisopropoxybis(acetylacetonate).Among them, it is preferable to use titanium oxide.
In addition, in preparing the surface treatment agent, one type of these compounds may be used, or two or more types may be used.

<Compound (C)>
Compound (C) is not particularly limited as long as it contains barium as an element. Examples of compounds containing barium include barium hydroxide, barium oxide, barium fluoride, barium iodide, barium sulfate, barium hydrogen sulfate, barium sulfite, barium nitrate, barium phosphate, barium hydrogen carbonate, barium acetate, and barium chromate. Among them, it is preferable to use barium sulfate.
In addition, in preparing the surface treatment agent, one type of these compounds may be used, or two or more types may be used.

The content of silicone resin (A) (meaning the total content when multiple silicone resins are used) is within the range of 20% by mass to 90% by mass, and preferably within the range of 54% by mass to 80% by mass, based on the total mass of the silicone resin (A), compound (B), compound (C), and compound (E).

In the surface treatment agent, the ratio (B M /A M ) of the mass (A _M ) of the silicone resin (A) [when multiple silicone resins are used, this refers to the total mass] to the mass (B _{M )} of the compound ( _B ) [when multiple compounds are used, this refers to the total mass] is preferably in the range of 0.05 to 3.12, and more preferably in the range of 0.10 to 0.61.
The ratio ( _CM /AM) of the mass ( _AM ) of the silicone resin (A) to the mass ( _CM ) of the compound (C) [when multiple compounds are used, this refers to the total _mass ] is preferably in the range of 0.02 to 0.55, more preferably in the range of 0.04 to 0.22.

<Aromatic Hydrocarbon Solvent (D)>
The aromatic hydrocarbon solvent (D) may be a hydrocarbon having a unit of a single ring or multiple planar rings consisting of six carbon atoms in which single bonds and double bonds are arranged alternately and electrons are delocalized, and the type of the aromatic hydrocarbon solvent is not particularly limited.

The aromatic hydrocarbon solvent (D) is not particularly limited as long as it has the above-mentioned unit, but is preferably one having a solubility parameter (SP) value in the range of 8.5 to 9.5, more preferably in the range of 8.8 to 9.3. More specifically, examples of the solvent include benzene, toluene, o-xylene, p-xylene, m-xylene, ethylbenzene, and cumene. These organic solvents may be used alone or in combination of two or more in the preparation of the surface treatment agent.

The content of aromatic hydrocarbon solvent (D) in the surface treatment agent is not particularly limited, but is preferably in the range of 40% by mass or more and 99% by mass or less, and more preferably in the range of 45% by mass or more and 95% by mass or less.

<Alkoxysilane (E)>
The alkoxysilane having an amino group [hereinafter simply referred to as "alkoxysilane (E)"] is not particularly limited as long as it has an amino group, and examples thereof include N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, polymers of the silane coupling agents, and copolymers with the polymers.

In preparing the surface treatment agent, when an alkoxysilane (E) is used, the ratio (E M /A M ) of the mass (A _M ) of the silicone resin (A) [meaning the total mass when multiple silicone resins are used] to the mass (E _M ) of the _alkoxysilane ( _E ) [meaning the total mass when multiple alkoxysilanes are used] is preferably in the range of 0.01 to 0.43, more preferably in the range of 0.17 to 0.39, but is not limited to these ranges.

<Other additives>
The surface treatment agent according to the present embodiment may contain various additives as necessary. Examples of the additives include surfactants, antifoaming agents, leveling agents, thickening agents, antibacterial and antifungal agents,
Examples of additives include, but are not limited to, colorants, fluororesins, etc. By adding these additives to the surface treatment agent, it is possible to improve the storage property and drying property of the surface treatment agent, improve the workability in the production of a surface treatment film using the surface treatment agent, and improve the appearance (particularly the design) of the produced surface treatment film. These additives may be added within a range that does not impair the effects of the present invention, and the content of the additives is at most several mass % relative to the mass of the surface treatment agent.

(Method of manufacturing surface treatment agent)
The surface treatment agent according to the present embodiment can be produced by mixing a silicone resin (A), a titanium compound (B), a barium compound (C), an aromatic hydrocarbon solvent (D), an alkoxysilane (E), and the like.

(Carbon steel material having a surface treatment coating and its manufacturing method)
The method for producing a carbon steel material having a surface treatment film according to this embodiment includes a first step of contacting the surface treatment agent with the surface or on the surface of a carbon steel material, and a second step of drying the surface treatment agent that has been in contact with the carbon steel material to form a surface treatment film. By carrying out these steps, a carbon steel material having a surface treatment film can be produced.

Before carrying out the first step, the metal material may be pretreated in order to remove any oil or dirt adhering to the surface of the carbon steel material. The pretreatment method is not particularly limited, and examples include washing with hot water, cleaning with a solvent, and alkaline degreasing.

As the contact method in the first step, various contact methods can be used, but it is preferable to appropriately select the most suitable method depending on the shape of the metal material to be treated, etc. Specific examples include coating methods such as immersion treatment, spray treatment, pouring treatment, roll coater method, bar coating method, and electrolytic deposition; coating methods using one or more coating devices such as spin coaters, slit coaters, die coaters, blade coaters, and dispensers; and the like; but a coating method using a dispenser that can stably coat a predetermined amount of surface treatment agent is preferred.

The temperature (ambient temperature) during drying in the second step is not particularly limited, but is preferably in the range of 40 to 250°C, and more preferably in the range of 60 to 180°C. The drying method is not particularly limited, and examples include a method in which the surface treatment agent in contact with the carbon steel material is heated by hot air, an induction heater, infrared rays, near infrared rays, etc. to dry the surface treatment agent. In addition, there is no particular limit to the heating time, and the optimal conditions may be set appropriately depending on the type of material used, the surface of the carbon steel material, or the amount of surface treatment agent attached to the surface.

The method for producing a carbon steel material having a surface treatment coating according to this embodiment may further include a third step of contacting the surface or surface of the metal material with a primer containing one or more selected from the group consisting of a silane coupling agent having an amino group, a polymer of the silane coupling agent, a copolymer with the polymer, and phosphoric acid before carrying out the first step (or after the pretreatment, if a pretreatment is carried out), and a fourth step of drying the primer that has been contacted with the carbon steel material with or without rinsing to form a primer coating. In this way, a metal material having a surface treatment coating and a primer coating can be produced by carrying out the first and second steps after carrying out the third and fourth steps.

The surface treatment agent includes at least one selected from the group consisting of a silane coupling agent having an amino group, a polymer of the silane coupling agent, a copolymer with the polymer, and phosphoric acid. The silane coupling agent having an amino group is not particularly limited as long as it has one amino group, and examples thereof include N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.
There are no particular limitations on the phosphate phosphate as long as it contains phosphoric acid, and examples thereof include manganese phosphate, iron phosphate, zinc phosphate, and calcium zinc phosphate, with manganese phosphate being preferred among these.

The solvent contained in the base treatment agent is not particularly limited, but examples of the solvent include organic solvents such as alcohol, acetone, acetonitrile, benzene, cyclohexane, methyl acetate, ethyl acetate, and methyl ethyl ketone; mixtures of these organic solvents and water; and the like. As the organic solvent, an alcohol having 5 or less carbon atoms is preferable. The mass ratio of water contained in the mixture is preferably less than 5 mass%. In addition, the base treatment agent may contain additives such as a leveling agent for improving wettability to metal materials, a film-forming assistant for improving film-forming properties, an organic crosslinking agent or an inorganic crosslinking agent for making the base coating stronger, a defoaming agent for suppressing foaming, a thickener for controlling viscosity, and a rust inhibitor, and these additives may be blended within a range that does not impair the effects of the present invention.

As the contact method in the third step, various contact methods can be used, but it is preferable to select the most suitable method depending on the shape of the metal material to be treated. Specifically, in addition to the method of applying using the above-mentioned application device, methods such as immersion treatment, spray treatment, pouring treatment, roll coater method, bar coating method, and electrolytic deposition can be mentioned, but are not limited to these methods. In addition, as the drying method in the fourth step, methods of heating and drying using hot air, induction heater, infrared rays, near infrared rays, etc., and methods of drying by distillation under reduced pressure can be mentioned, but are not limited to these. The temperature during heating and drying is not particularly limited, but is preferably within the range of 40 to 250°C (ambient temperature), and more preferably within the range of 60 to 180°C (ambient temperature). In addition, there is no particular limit to the heating time, and the optimal conditions can be set appropriately depending on the type of material used, the surface of the metal material, or the amount of the primer attached to the surface.

<Carbon steel material>
The carbon steel material is not particularly limited, and examples thereof include steel materials that are alloys of iron and carbon and have a carbon content of 0.02% to 2.14% by mass, but high carbon steel containing 0.95% or more by mass is preferable, and high carbon chromium bearing steel used for machine element members and the like is more preferable. High carbon chromium bearing steel is a carbon steel material in which chromium, nickel, molybdenum, etc. are added to the carbon contained in steel in large amounts, each of which has special properties. The upper limit of the carbon content of high carbon steel is not limited, and may be 3% or less by mass, or 2.14% or less by mass.
In this specification, a carbon steel material will be described as an example of a material to which the surface treatment agent is applied. However, the material to which the surface treatment agent according to this embodiment is applied is not limited to metal materials, and may be any material that requires an electrolytic corrosion resistant coating.

(Carbon steel material with surface treatment coating)
The carbon steel material having a surface treatment coating according to this embodiment has the above-mentioned surface treatment coating on or at the surface of the carbon steel material. This surface treatment coating contains a silicone resin (A), a compound (B), a compound (C), and a polymer derived from an alkoxysilane (E) having an amino group. It is considered that the polymer derived from the alkoxysilane (E) having an amino group in the surface treatment coating plays a role of stably holding the silicone resin (A), the compound (B), and the compound (C) together (binder effect).
In addition, the ratio (B _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (B _M ) of the compound (B) is within the range of 0.05 or more and 3.12 or less.
The ratio ( _CM / _AM ) of the mass ( _AM ) of the silicone resin (A) to the mass ( _CM ) of the compound (C) is within a range of 0.02 to 0.55. The mass ( _AM ) of the silicone resin (A), the mass ( _BM ) of the compound (B), and the mass ( _CM ) of the compound (C) contained in the surface treatment agent are maintained in the surface treatment coating formed by the surface treatment agent.

The carbon steel material having the surface treatment coating according to this embodiment may have a base coating between the carbon steel material and the surface treatment coating. This base coating contains one or more selected from the group consisting of a silane coupling agent having an amino group, a polymer of the silane coupling agent, a copolymer with the polymer, and phosphoric acid. When the above-mentioned additive is blended in the base treatment agent that forms the base coating, the base coating may further contain the additive.

The carbon steel material having the surface treatment coating can be produced by the above-mentioned production method. The thickness of the surface treatment coating is not particularly limited, but is preferably in the range of 3 μm to 100 μm, and more preferably in the range of 20 μm to 80 μm, per side. The thickness of the surface treatment coating can be measured by observing a cross section of the coating with an electron microscope.
The carbon steel material having the above-mentioned surface treatment coating has excellent resistance to electric corrosion and is therefore suitable for industrial products such as automobile parts such as bearings and motors, home appliance parts such as home appliance motors and reactors, office automation equipment parts such as printed wiring boards and inductors, and medical equipment.

The following examples concretely demonstrate the effects of the present invention. However, the following examples do not limit the present invention.

(1) Test material (material)
The following commercially available materials were used as test materials:
(M1) High carbon chromium bearing steel SUJ2: plate thickness 1.0 mm, carbon content 1.0 mass%

(2) Pretreatment (alkaline degreasing)
The surfaces of the various test materials were degreased by immersing them in a 2% aqueous solution of an alkaline degreaser (Fine Cleaner E6406 manufactured by Nippon Parkerizing Co., Ltd.) at 60°C for 30 seconds to remove oil and dirt from the surfaces. Next, the test materials were rinsed with tap water, and then poured with pure water, and the surfaces of the test materials were dried at 100°C.

(3) Preparation of Surface Treatment Agent Surface treatment agents of Examples 1 to 19 and Comparative Examples 1 to 5 were prepared by mixing the components as shown in Table 1. The types of the components shown in Table 1 are shown in Tables 2 to 6. The mixed amounts of silicone resin (A) and alkoxysilane (E) shown in Table 1 are the masses of the compounds excluding the solvent and the like.

(4) Metallic material having a surface treatment film As shown in Table 7, various surface treatment agents were contacted with the surfaces of various pretreated test materials. Thereafter, without washing with water, the surface treatment agents contacted with the test materials were dried at the drying temperature (ambient temperature) shown in Table 7 to prepare test materials (test plates) having surface treatment films with the thicknesses shown in Table 7. The contact with the surface treatment agent was performed by coating. If necessary, before contacting with the surface treatment agent, the various pretreated test materials were immersed in the primer treatment agent shown in Table 7 and dried to form a primer film on the surface of the test materials. The types of primer treatment agents shown in Table 7 are shown in Table 8.

The surface preparation in Table 8 was carried out specifically as follows.
S1: A treatment agent prepared by diluting 3-aminopropyltriethoxylane ("KBE-903" manufactured by Shin-Etsu Chemical Co., Ltd.) with ethanol to 10% by mass was applied to the test material at room temperature, and then the test material was dried until it reached 100°C (test material temperature) to form a base coating.
S2: Various test materials were immersed for 30 seconds in a surface conditioner obtained by diluting a manganese phosphate treatment surface treatment adjuster ("Preparen 55" manufactured by Nippon Parkerizing Co., Ltd.) to 0.3% by mass with tap water. Next, a manganese phosphate-based surface treatment agent ("Palphos M1A" manufactured by Nippon Parkerizing Co., Ltd.) was diluted to 14% by mass with tap water, and the total acidity was adjusted to 50 points, the free acidity to 8.6 points, the acid ratio (total acidity/free acidity) to 5.8, and the iron concentration to 1.5 g/L. The iron-based metal material that had undergone surface adjustment was immersed for 900 seconds in a chemical conversion treatment solution that was further heated to 97 ° C. Next, the material was washed with tap water, further poured with pure water, and the surface of the test material was dried at 100 ° C. (ambient temperature) for 10 minutes to form a base film mainly composed of manganese phosphate and manganese iron phosphate.

(5) Evaluation Tests The following evaluation tests were carried out on the various test plates. The results of each evaluation test are shown in Table 9. From a practical standpoint, those without an "x" in each evaluation item shown in Table 9 were deemed to have passed. In addition, those whose liquid stability or coatability was poor and could not be evaluated were marked with a "-".

<Electric corrosion resistance after heating>
Each test plate (No. 1 to No. 34) was cut into a size of 70 × 150 mm, heated in an oven at 200 ° C. for 10 hours, and then left at room temperature (25 ° C.) for 24 hours. Next, in accordance with JIS C2110-1:2016, a voltage was applied to each test plate at a voltage increase rate of 10 V / s, the maximum voltage when electricity was passed through each test plate was measured, and the electrolytic corrosion resistance after heating was evaluated based on the following evaluation criteria.
(Evaluation criteria)
◎: 1000V or more 〇: 500V or more to less than 1000V ○△: 300V or more to less than 500V △: 200V or more to less than 300V ×: Less than 200V

<Adhesion test after heating>
After cutting each test plate into a size of 70×150 mm, it was heated in an oven at 200° C. for 10 hours, and then left at room temperature (25° C.) for 24 hours. Next, each test plate was cut with 11 cuts vertically and horizontally at 1 mm intervals to create a checkerboard (10×10=100 squares)-like cut. Next, cellophane tape was applied to the checkerboard-like cut, and the cellophane tape was peeled off to count the number of remaining squares out of 100 squares. The remaining rate was calculated from the measurement results, and the adhesion after heating was evaluated based on the following evaluation criteria.
(Evaluation criteria)
◎: Residual rate 95% to 100%
○: Residual rate 90% or more but less than 95% ○△: Residual rate 70% or more but less than 90% △: Residual rate 50% or more but less than 70% ×: Residual rate 0% or more but less than 50%

<Electric corrosion resistance after sliding>
After cutting each test plate into a size of 30×100 mm, two test plates were stacked on each other with their treated surfaces (contact area 30 mm×30 mm) using a drawbead tester, and slid once with a pressure load of 200 kg and a surface pressure of 22.2 kg/ ^cm2 . Next, according to JIS C2110-1:
In accordance with IEC 61015-2016, a voltage was applied to the sliding surfaces of various test plates at a voltage rise rate of 10 V/s, the maximum voltage when electricity was passed through each test plate was measured, and the resistance to electrolytic corrosion after heating was evaluated based on the following evaluation criteria.
(Evaluation criteria)
◎: 1000V or more 〇: 500V or more to less than 1000V ○△: 300V or more to less than 500V △: 200V or more to less than 300V ×: Less than 200V

Claims (8)

The composition contains a silicone resin (A), a titanium compound (B), a barium compound (C), an aromatic hydrocarbon solvent (D), and an alkoxysilane having an amino group (E),
(I) the ratio (B _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (B _M ) of the compound (B) is within the range of 0.05 to 3.12,
(II) the ratio (C _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (C _M ) of the compound (C) is within the range of 0.02 or more and 0.55 or less;
(III) A surface treatment agent for carbon steel materials, wherein the ratio (E _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (E _M ) of the compound (E) is within the range of 0.01 or more and 0.43 or less. A method for producing a carbon steel material having a surface treatment coating, comprising a first step of contacting the surface treatment agent according to claim 1 with the surface or on the surface of the carbon steel material, and a second step of drying the surface treatment agent that has been brought into contact with the carbon steel material to form a surface treatment coating. The method for producing a carbon steel material according to claim 2, further comprising a base coating formation step, prior to the first step, of contacting the surface or the surface of the carbon steel material with a silane coupling agent having an amino group, a polymer of the silane coupling agent, a copolymer with the polymer, or a base treatment agent containing phosphoric acid to form a base coating. A carbon steel material having a surface treatment coating obtained by the manufacturing method described in claim 2 or 3, wherein the thickness of the surface treatment coating is within the range of 3 μm to 100 μm. A surface treatment coating is provided on or at the surface of a carbon steel material.
the surface treatment coating contains a silicone resin (A), a titanium compound (B), a barium compound (C), and a polymer derived from an alkoxysilane having an amino group (E);
(I) the ratio (B _M /A _M ) of the mass (A _M ) of the silicone resin (A) to the mass (B _M ) of the compound (B) is within the range of 0.05 to 3.12,
(II) A carbon steel material having a surface treatment coating, wherein the ratio ( _CM / _AM ) of the mass ( _AM ) of the silicone resin (A) to the mass ( _CM ) of the compound (C) is within the range of 0.02 or more and 0.55 or less. a base coating between the carbon steel material and the surface treatment coating;
6. The carbon steel material having a surface treatment coating according to claim 5, wherein the undercoat coating comprises at least one selected from the group consisting of a silane coupling agent having an amino group, a polymer of the silane coupling agent, a copolymer of the polymer, and phosphoric acid. A carbon steel material having a surface treatment coating according to claim 5, wherein the thickness of the surface treatment coating is in the range of 3 μm to 100 μm. The high carbon steel material having the surface treatment coating according to any one of claims 5 to 7, wherein the carbon steel material is a high carbon steel containing 0.95 mass% or more of carbon.