Detailed Description
The surface treatment agent of the present invention, the carbon steel material having the surface treatment coating film, and the method for producing the same will be described below.
(Surface treatment agent)
The surface treatment agent of the present embodiment 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). By using this surface treatment agent, a surface treatment coating film excellent in electrical corrosion resistance (particularly in high-temperature environments) can be formed on a carbon steel material. Further, the high temperature means at least 100 ℃ or more, preferably 150 ℃ or more, more preferably 200 ℃ or more. As described above, the surface treatment agent of the present embodiment is useful as an electrolytic corrosion resistant coating film forming agent because the surface treatment agent can form a surface treatment coating film excellent in electrolytic corrosion resistance. The surface-treated coating film having excellent electrical corrosion resistance is useful for carbon steel materials and the like used for mechanical element members constituting industrial products such as automobiles, home appliances, OA equipment, and medical equipment.
< Silicone resin (A) >
The silicone resin (a) is not particularly limited as long as it has an organopolysiloxane structure containing a plurality of siloxane bonds and having an organic group bonded to silicon (Si), and preferably has an organopolysiloxane structure having at least two or more organic groups bonded to Si in one molecule. In addition, the position where the organic group is bonded is not particularly limited, and may be bonded to the main chain, the side chain, or the terminal. The silicone resin (a) may be a homopolymer having the above-described organopolysiloxane structure, a mixture of a homopolymer having the above-described organopolysiloxane structure and a homopolymer having a polysiloxane structure, or a copolymer (block copolymer or graft polymer) having the above-described organopolysiloxane structure and a polysiloxane structure. The silicone resin (a) may be of an addition type or a condensation type. The silicone resin (a) may be any of a thermosetting type, a room temperature curing type (RVT), and a UV curing type.
Examples of the organic group bonded to Si in the organopolysiloxane structure include, but are not limited to, saturated hydrocarbon groups, unsaturated hydrocarbon groups, haloalkyl groups, and epoxycyclohexyl groups. Examples of the saturated hydrocarbon group include a linear or branched alkyl group, a cycloalkyl group, and the like, but are not limited thereto. Examples of the unsaturated hydrocarbon group include, but are not limited to, a linear or branched alkenyl group, a cycloalkenyl alkyl group, an aryl group, and the like. 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 the haloalkyl group include chloromethyl, 3-chloropropyl, 1-chloro-2-methylpropyl, and 3, 3-trifluoropropyl. Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl and the like. Examples of cycloalkyl groups include cyclopentyl and cyclohexyl. Examples of the straight-chain or branched alkenyl group include vinyl, 1-propenyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, pentenyl, hexenyl and the like. Examples of the cycloalkenyl group include cyclopentenyl group and cyclohexenyl group. Examples of the cycloalkenyl alkyl group include cyclopentylethyl, cyclohexenylethyl, and cyclohexenylpropyl. Examples of the aryl group include phenyl.
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 or more hydrogen atoms bonded to Si in one molecule, a polysiloxane structure having at least two or more alkoxy groups bonded to Si in one molecule, and the like. Examples of the alkoxy group include methoxy, ethoxy, propoxy, and butoxy. The alkoxy group may be linear or branched.
In the preparation of the surface treatment agent, one kind of the above-mentioned various silicone resins may be used, or two or more kinds may be used in combination. As a preferred embodiment of the silicone resin (a), a mixture of a homopolymer having an organopolysiloxane structure having at least two or more Si-bonded unsaturated hydrocarbon groups in one molecule and a homopolymer having a polysiloxane structure having at least two or more Si-bonded hydrogen atoms in one molecule can be given.
Examples of homopolymers having an organopolysiloxane structure having at least two or more unsaturated hydrocarbon groups bonded to Si in one molecule include dimethylpolysiloxane having dimethylvinylsiloxane groups at both ends of a molecular chain, dimethylsiloxane-methylphenylsiloxane copolymers having dimethylvinylsiloxane groups at both ends of a molecular chain, dimethylsiloxane-methylvinylsiloxane copolymers having trimethylsiloxane groups at both ends of a molecular chain, dimethylsiloxane-methylvinylsiloxane terpolymers having trimethylsiloxane groups at both ends of a molecular chain, dimethylsiloxane-methylvinylsiloxane copolymers having silanol groups at both ends of a molecular chain, methylvinylpolysiloxanes having silanol groups at both ends of a molecular chain, and the like. In addition, various polymers, copolymers and terpolymers may be mentioned, in which a part of methyl groups of the copolymers and terpolymers is substituted with alkyl groups other than methyl groups, such as ethyl groups and propyl groups, or halogenated alkyl groups, such as 3, 3-trifluoropropyl groups and 3, 3-trichloropropyl groups. Mixtures of two or more selected from these polymers, copolymers and terpolymers may also be used for the preparation of the surface treatment agent.
The homopolymer having a polysiloxane structure having at least two or more hydrogen atoms bonded to Si in one molecule is not particularly limited, and examples thereof include an SiH group having at least two or more hydrogen atoms bonded to Si in one molecule, a linear, cyclic, branched, and three-dimensional network organopolysiloxane having a diorganosiloxane structure as a main chain and both ends of a molecular chain being blocked with triorganosiloxy groups repeatedly, and the like. More specifically, methylhydrogen polysiloxane having trimethylsiloxy groups at both ends of a molecular chain, dimethylsiloxane-methylhydrogen siloxane copolymer having trimethylsiloxy groups at both ends of a molecular chain, methylhydrogen polysiloxane having silanol groups at both ends of a molecular chain, dimethylsiloxane-methylhydrogen siloxane copolymer having silanol groups at both ends of a molecular chain, dimethylsiloxane having dimethylhydrogen siloxy groups at both ends of a molecular chain, methylhydrogen polysiloxane having dimethylhydrogen siloxy groups at both ends of a molecular chain, dimethylsiloxane-methylhydrogen siloxane copolymer having dimethylhydrogen siloxy groups at both ends of a molecular chain, and the like are exemplified. Mixtures of two or more selected from these polymers and copolymers may also be used for the preparation of the surface treatment agent.
The weight average molecular weight of the silicone resin (a) is not particularly limited, and is usually in the range of 6000 to 45000, preferably 6500 to 40000. The weight average molecular weight is a value in terms of polystyrene measured by GPC (gel permeation chromatography).
< Compound (B) >
The compound (B) is not particularly limited as long as it contains titanium as an element. Examples of the titanium-containing compound include titanyl sulfate, titanyl nitrate, titanium nitrate, titanyl chloride, titanium chloride, titania sol, titanium oxide, potassium oxalate titanate, titanium lactate, titanium tetraisopropoxide, titanium tetra-acetylacetonate, titanium diisopropyloxide, and diisopropyl di (acetylacetonate) titanate. Titanium oxide is particularly preferably used.
In addition, in the preparation of the surface treatment agent, one kind of these compounds may be used, or two or more kinds may be used.
< Compound (C) >
The compound (C) is not particularly limited as long as barium is contained as an element. Examples of the compound containing barium include barium hydroxide, barium oxide, barium fluoride, barium iodide, barium sulfate, barium bisulfate, barium sulfite, barium nitrate, barium phosphate, barium bicarbonate, barium acetate, and barium chromate. Barium sulfate is particularly preferably used.
In addition, in the preparation of the surface treatment agent, one kind of these compounds may be used, or two or more kinds may be used.
The content of the silicone resin (a) (when a plurality of silicone resins are used, the total content is referred to as the total content) is in the range of 20 mass% to 90 mass%, preferably 54 mass% to 80 mass%, relative to the total mass of the silicone resin (a), the compound (B), the compound (C) and the compound (E).
In the surface treatment agent, the ratio (BM/AM) of the mass (BM) [ total mass in the case of using plural kinds of compounds ] to the mass (aM) of the silicone resin (a) [ total mass in the case of using plural kinds of silicone resins ] is preferably in the range of 0.05 to 3.12 inclusive, more preferably in the range of 0.10 to 0.61 inclusive.
The ratio (CM/AM) of the mass (CM) [ in the case of using a plurality of compounds, means the total mass ] of the compound (C) to the mass (aM) of the silicone resin (a) 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) includes, but is not particularly limited to, hydrocarbons having, as a unit, a single ring or a plurality of planar rings of six carbon atoms in which single bonds and double bonds are alternately arranged and electron-delocalized.
The aromatic hydrocarbon solvent (D) is not particularly limited as long as it has the above units, and preferably has 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, benzene, toluene, o-xylene, p-xylene, m-xylene, ethylbenzene, cumene, and the like can be mentioned. In addition, in the preparation of the surface treatment agent, one kind of these organic solvents may be used, or two or more kinds may be used in combination.
The content of the aromatic hydrocarbon solvent (D) in the surface treatment agent is not particularly limited, but is preferably in the range of 40 mass% to 99 mass%, more preferably in the range of 45 mass% to 95 mass%, based on the mass ratio.
< Alkoxysilane (E) >
The alkoxysilane having an amino group [ hereinafter, abbreviated as "alkoxysilane (E)" ] is not particularly limited as long as it has an amino group, and examples thereof include N- (2-aminoethyl) -3-aminopropyl methyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, a polymer of the silane coupling agent, and a copolymer with the polymer.
In the preparation of the surface treatment agent, in the case of using the alkoxysilane (E), the ratio (EM/AM) of the mass (EM) of the alkoxysilane (E) [ in the case of using a plurality of alkoxysilanes, means the total mass ] to the mass (aM) of the silicone resin (a) [ in the case of using a plurality of silicone resins, means the total mass ] 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 of the present embodiment may contain various additives as needed. Examples of the additive include, but are not limited to, surfactants, defoamers, leveling agents, thickeners, antibacterial and antifungal agents, colorants, and fluororesins. By adding these additives to the surface treatment agent, the storability and drying properties of the surface treatment agent can be improved, the workability in the production of the surface treatment film using the surface treatment agent can be improved, and the appearance (particularly, design) of the produced surface treatment film can be improved. These additives may be added in an amount of up to several percent by mass relative to the mass of the surface treatment agent within a range not to impair the effects of the present invention.
(Method for producing surface treatment agent)
The surface treatment agent of the present embodiment can be produced by mixing the silicone resin (a), the titanium compound (B), the barium compound (C), the aromatic hydrocarbon solvent (D), the alkoxysilane (E), and the like.
(Carbon Steel Material having surface-treated coating film and method for producing the same)
The method for producing a carbon steel material having a surface-treated coating film according to the present embodiment includes a first step of bringing the surface-treating agent into contact with the surface or on the surface of the carbon steel material, and a second step of drying the surface-treating agent that has been brought into contact with the carbon steel material to form the surface-treated coating film. By performing these steps, a carbon steel material having a surface-treated coating film can be produced.
Before the first step, the metal material may be subjected to pretreatment in order to remove oil and dirt adhering to the surface of the carbon steel material. The pretreatment method is not particularly limited, and examples thereof include hot water washing, solvent washing, alkali degreasing washing, and the like.
As the contact method in the first step, various contact methods can be used, and it is preferable to appropriately select the most suitable method according to the shape of the treated metal material or the like. Specifically, examples of the method include a coating method such as a dipping method, a spray treatment method, a flow coating method, a roll coating method, a bar coating method, and an electrolytic deposition method, a method of coating using one or more coating apparatuses such as a spin coater, a slit coater, a die coater, a blade coater, and a dispenser, and a method of coating using a dispenser capable of stably applying a predetermined amount of a surface treatment agent are preferable.
The temperature (ambient temperature) at the time of drying in the second step is not particularly limited, but is preferably in the range of 40 to 250 ℃, more preferably in the range of 60 to 180 ℃. The drying method is not particularly limited, and there is a method of drying the surface treatment agent by heating the surface treatment agent that has been brought into contact with the carbon steel material by hot air, an induction heater, infrared rays, near infrared rays, or the like. The heating time is not particularly limited, and the most suitable conditions may be appropriately set according to the type of material used, the surface of the carbon steel material, the amount of the surface treatment agent attached to the surface, and the like.
The method for producing a carbon steel material having a surface-treated coating according to the present embodiment may further include a third step of bringing one or more base treatment agents 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 silane coupling agent and the polymer, and phosphoric acid into contact with the surface or on the surface of a metal material before the first step (in the case of performing a pretreatment, after the pretreatment), and a fourth step of washing or not washing and drying the base treatment agent brought into contact with the carbon steel material to form a base coating. By performing the first step and the second step after performing the third step and the fourth step in this manner, a metal material having a surface treatment coating film and a base coating film can be manufactured.
The substrate treating agent 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 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-aminopropyl methyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyl trimethoxysilane, and 3-aminopropyl triethoxysilane.
The phosphoric acid is not particularly limited as long as it is contained, and examples thereof include manganese phosphate, iron phosphate, zinc calcium phosphate, and the like, and among these, manganese phosphate is preferably used.
The solvent contained in the substrate treating agent is not particularly limited, and examples thereof include organic solvents such as alcohols, acetone, acetonitrile, benzene, cyclohexane, methyl acetate, ethyl acetate, and methyl ethyl ketone, and mixtures of these organic solvents and water. The organic solvent is preferably an alcohol having 5 or less carbon atoms. In addition, the mass proportion of water contained in the mixture is preferably less than 5 mass%. The substrate treating agent may contain a leveling agent for improving wettability to a metal material, a film forming aid for improving film forming property, an organic crosslinking agent and an inorganic crosslinking agent for making a substrate film a stronger film, an antifoaming agent for suppressing foaming, a thickener for controlling tackiness, an additive such as an anticorrosive agent, and the like, which may be blended in a range not impairing the effect of the present invention.
As the contact method in the third step, various contact methods can be used, and it is preferable to appropriately select the most suitable method according to the shape of the treated metal material or the like. Specifically, examples of the method of coating using the coating apparatus include, but are not limited to, dipping, spraying, flow coating, roll coating, bar coating, and electrolytic deposition. The drying method in the fourth step includes, but is not limited to, a method of drying by heating using hot air, an induction heater, infrared rays, near infrared rays, or the like, a method of drying by distillation under reduced pressure, and the like. The temperature at the time of heat drying is not particularly limited, but is preferably in the range of 40 to 250 ℃ (ambient temperature), more preferably in the range of 60 to 180 ℃ (ambient temperature). The heating time is not particularly limited, and the most suitable conditions may be appropriately set according to the type of material used, the amount of the substrate treating agent attached to the surface or the surface of the metal material, and the like.
< Carbon Steel Material >
The carbon steel material is not particularly limited, and examples thereof include steel materials containing 0.02 to 2.14 mass% of carbon, preferably high carbon steel containing 0.95 mass% or more of carbon, and more preferably high carbon chromium bearing steel used for machine element members and the like. The high-carbon chromium bearing steel is a carbon steel material with various special properties, in which chromium, nickel, molybdenum and the like are added to carbon contained in a large amount in the steel. The upper limit of the carbon content of the high-carbon steel is not limited, and may be 3 mass% or less or 2.14 mass% or less.
In the present specification, a carbon steel material is described as an example of a target material to which the surface treatment agent of the present embodiment is applied, but the target material to which the surface treatment agent of the present embodiment is not limited to a metal material, and any material may be used as long as it is a material that requires an electrolytic corrosion resistant coating.
(Carbon steel Material with surface-treated coating)
The carbon steel material having the surface-treated coating film according to the present embodiment has the surface-treated coating film on the surface or on the surface of the carbon steel material. The surface treatment coating film 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-treated coating film stably retains the functions (binder effects) of the silicone resin (a), the compound (B) and the compound (C).
Further, the ratio (BM/AM) of the mass (BM) of the compound (B) to the mass (aM) of the silicone resin (a) is in the range of 0.05 to 3.12.
The ratio (CM/AM) of the mass (CM) of the compound (C) to the mass (aM) of the silicone resin (a) is in the 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 also remain unchanged in the surface treatment coating film formed of the surface treatment agent.
In addition, the carbon steel material having the surface-treated coating film of the present embodiment may have a base coating film between the carbon steel material and the surface-treated coating film. The base film 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 with the polymer, and phosphoric acid. In the case where the above-mentioned additive is blended into the substrate treating agent for forming the substrate film, the substrate film may further contain the additive.
The carbon steel material having the surface-treated coating film can be produced by the production method described above. The film thickness of the surface-treated coating film is not particularly limited, but is preferably in the range of 3 μm to 100 μm, more preferably in the range of 20 μm to 80 μm. The film thickness of the surface-treated coating can be measured by observing the cross section of the coating with an electron microscope.
The carbon steel material having the surface-treated coating film is excellent in electrical corrosion resistance and therefore is suitable for use in industrial products such as bearings, automobile parts such as motors, home electric appliances such as home electric motors and reactors, OA equipment parts such as printed circuit boards and inductors, and medical equipment.
Examples
Hereinafter, the operational effects of the present invention are specifically shown by examples. However, the present invention is not limited to the following examples.
(1) Test material (raw material)
The following commercial materials were used as test materials.
(M1) high carbon chromium bearing Steel SUJ2: 1.0mm in plate thickness, 1.0% in carbon content by mass
(2) Pretreatment (alkali degreasing cleaning)
The surfaces of the respective test materials were immersed in a 2% aqueous solution of an alkali degreasing agent (FINE CLEANER E6406, manufactured by japan pakak) at 60 ℃ for 30 seconds to perform degreasing treatment, and oil and dirt on the surfaces were removed. Then, the sample was washed with tap water, further washed with pure water, and the surface of the sample was dried at 100 ℃.
(3) Preparation of surface treatment agent
The surface treatments 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. In addition, the mixing amount of the silicone resin (a) and the alkoxysilane (E) shown in table 1 is a mass as a compound other than a solvent or the like.
TABLE 1
TABLE 1 composition of surface treatment agent
TABLE 2
TABLE 2
TABLE 3
TABLE 3 Table 3
TABLE 4
TABLE 4 Table 4
TABLE 5
TABLE 5
TABLE 6
TABLE 6
(4) Metal material with surface treatment coating
As shown in table 7, various surface treatments were brought into contact with the surfaces of the various test materials subjected to the pretreatment. Thereafter, the treatment agent having been brought into contact with the surface of the test material was dried at the drying temperature (ambient temperature) shown in table 7 without washing with water, and the test material (test board) having the surface-treated coating film with the film thickness shown in table 7 was produced. The surface treatment agent is applied by contact. Before the surface treatment agent was brought into contact as needed, each of the pretreated materials was immersed in the substrate treatment agent shown in table 7 and dried, whereby a substrate film was formed on the surface of the material. The types of the substrate treating agents shown in table 7 are shown in table 8.
TABLE 7
TABLE 7 preparation of test plates
TABLE 8
TABLE 8
The substrate treatment in table 8 was specifically performed as follows.
S1, a treatment chemical obtained by diluting 3-aminopropyl triethoxysilane (KBE-903 manufactured by Xinyue chemical Co., ltd.) to 10 mass% with ethanol is directly applied to a test material at normal temperature, and then dried until the temperature reaches 100 ℃.
S2, immersing various test materials in a surface conditioner obtained by diluting a surface treatment conditioner for manganese phosphate treatment ("PREPALENE" manufactured by Nippon Kagaku Co., ltd.) to 0.3 mass% with tap water for 30 seconds. Next, a manganese phosphate surface treatment chemical ("PF-M1A" manufactured by japan pakakoku corporation) was diluted to 14 mass% with tap water, the total acidity was adjusted to 50 points, the free acidity was adjusted to 8.6 points, the acid ratio (total acidity/free acidity) was adjusted to 5.8, and the iron component concentration was adjusted to 1.5g/L, and the surface-adjusted iron-based metal material was immersed in a chemical conversion treatment liquid heated to 97 ℃ for 900 seconds. Then, the sample was washed with tap water, further rinsed with pure water, and the surface of the sample was dried at 100 ℃.
(5) Evaluation test
The following evaluation tests were performed on various test panels. The results of each evaluation test are shown in Table 9. From the practical point of view, test boards having no "x" in each evaluation item shown in table 9 were accepted. The level that could not be evaluated because of poor liquid stability and coatability was "-".
< Resistance to electric erosion after heating >
After cutting each test plate (No. 1 to No. 34) into a size of 70X 150mm, it was heated in an oven at 200℃for 10 hours, followed by standing at room temperature (25 ℃) for 24 hours. Then, according to JIS C2110-1:2016, a voltage was applied to each test plate at a step-up rate of 10V/s, and the maximum voltage at the time of energizing each test plate was measured, and the electrical erosion resistance after heating was evaluated based on the following evaluation criteria.
(Evaluation criterion)
S is more than 1000V
A is 500V to less than 1000V
B is 300V to less than 500V
C is 200V to 300V
D is less than 200V
< Test of adhesion after heating >
After cutting the various test panels to a size of 70X 150mm, they were heated in an oven at 200℃for 10 hours and then left at room temperature (25 ℃) for 24 hours. Then, 11 slits were cut in each of the test boards at 1mm intervals in the horizontal and vertical directions, and a checkerboard (10×10=100 squares) grid-like cut was applied. Next, a cellophane tape was attached to the checkered cuts, and then the cellophane tape was peeled off, and the number of remaining squares in the 100 squares was measured. The residual ratio was calculated from the measurement results, and the adhesion after heating was evaluated based on the following evaluation criteria.
(Evaluation criterion)
S, the residual rate is more than 95 percent to 100 percent
A, the residual rate is more than 90% and less than 95%
The residual rate is more than 70% and less than 90%
C, the residual rate is more than 50% and less than 70%
D, the residual rate is more than 0% and less than 50%
< Resistance to electric erosion after sliding >
After each test plate was cut into a size of 30X 100mm, the treated surfaces of the two test plates were overlapped with each other (contact area: 30 mm. Times.30 mm) by using a bead tester, and were slid once under a pressure load of 200kg and a surface pressure of 22.2kg/cm2. Then, according to JIS C2110-1:2016, a voltage was applied to the sliding surfaces of the respective test plates at a step-up rate of 10V/s, and the maximum voltage at the time of energizing each test plate was measured, and the electrical erosion resistance after heating was evaluated based on the following evaluation criteria.
(Evaluation criterion)
S is more than 1000V
A is 500V to less than 1000V
B is 300V to less than 500V
C is 200V to 300V
D, less than 200V [ Table 9]
TABLE 9 evaluation results
Although the present invention has been described in detail with reference to specific examples, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.