JP2006192717A - Surface-treated metal, its manufacturing method and surface treatment liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-treated metal having a characteristic surface film and made excellent in contamination resistance by this surface film, a manufacturing method for suitably manufacturing the surface-treated metal and a surface treatment liquid for suitably manufacturing the characteristic surface film. <P>SOLUTION: The surface-treated metal comprises an inorganic-organic composite film, which is characterized in that the principal bond of a main skeleton is a siloxane bond and comprises at least one organic group selected from the group consisting of a 1-12C alkyl group, an aryl group, a carboxyl group, an amino group and a hydroxy group, as the uppermost surface layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface-treated metal having a coating made of an inorganic-organic composite on the surface and excellent in stain resistance, a method for producing the same, and a surface treatment liquid. More specifically, the present invention relates to a surface-treated metal having a surface modified by an inorganic-organic composite film and having excellent surface contamination resistance and weather resistance over a long period of time, and a method for producing the same. Moreover, it is related with the process liquid for manufacturing this surface treatment metal suitably.

  Metal materials typified by iron are generally used by painting for the purpose of improving durability such as corrosion resistance or for obtaining a beautiful appearance. Painted metal is widely used in the fields of home appliances, automobiles, building materials, outdoor structures, etc. Of these, especially those used outdoors are exposed to rain, wind, dust, etc. In addition to corrosion resistance, it is required to have excellent contamination resistance and weather resistance.

  One technique for improving the contamination resistance of surface-treated metals is to use a photocatalyst to decompose and remove surface contaminants. Such a method can be roughly divided into two methods depending on the difference in the structure of the surface film. Specifically, both a method of directly adding a substance exhibiting photocatalytic activity to the surface coating and a method of forming a coating having a photocatalytic effect on the coated surface have been studied.

  By the way, since organic substances are decomposed by the effect of the photocatalyst, there is a possibility that the coating film in which the above-mentioned photocatalyst is dispersed or the coating film in contact with the outermost film having the photocatalytic effect is gradually decomposed and deteriorated. . For this reason, attempts have been made to obtain a high anti-contamination effect by combining a photocatalyst with a coating film that is difficult to be decomposed by a photocatalyst using an inorganic resin or the like (see, for example, Patent Documents 1 to 6). .

JP-A-7-113272 JP-A-8-164334 JP-A-7-171408 JP-A-10-225658 JP 2000-317393 A JP 2000-63733 A

  The inventors of the present invention have also intensively studied a film that has little deterioration and excellent long-term weather resistance even when combined with particles having high photocatalytic activity. In this process, it has been found that an excellent anti-contamination effect can be obtained not only when combined with photocatalyst particles, but also only with a film containing no photocatalyst.

  That is, the present invention provides a surface-treated metal having excellent anti-contamination property, on which a film having an antifouling effect is formed, a production method for suitably producing the surface-treated metal, and a film for producing the above-mentioned film suitably. The object is to provide a surface treatment liquid.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a film made of an inorganic-organic composite having a specific bond as a main bond of the main skeleton and introducing a certain organic component. By using it as a matrix for the coating film, it was found that a surface-treated metal having a coating film having antifouling effect on the surface and excellent in stain resistance was obtained, and the present invention was completed. Specifically, it is as follows.

(1) As the outermost surface layer, at least one selected from the group consisting of an alkyl group, an aryl group, a carboxyl group, an amino group, and a hydroxyl group having a main bond of the main skeleton that is a siloxane bond and having 1 to 12 carbon atoms A surface-treated metal characterized by having an inorganic-organic composite film containing various organic groups.
(2) The surface-treated metal according to (1), wherein the organic group contained in the film is a phenyl group.
(3) The structure according to (1), wherein one or both of an ether bond and an amino bond are included in the bond of either or both of the main skeleton and the side chain of the inorganic-organic composite. Surface treatment metal.
(4) The surface-treated metal according to (1), (2) or (3), wherein the base metal used as the base is a metal plate.
(5) The metal plate is one type selected from the group consisting of a steel plate, a stainless steel plate, a titanium plate, an aluminum plate, an aluminum alloy plate, and a plated metal plate plated on each metal plate. The surface-treated metal according to (4).
(6) The surface-treated metal according to (4) or (5), wherein the metal plate is a coated metal plate having an organic coating film.
(7) at least one selected from the group consisting of tetraalkoxysilane, alkoxysilane having an alkyl group having 1 to 12 carbon atoms and a hydrolyzate thereof, and alkoxysilane having an aryl group and a hydrolyzate thereof; A surface treatment liquid comprising at least
(8) It further includes at least one selected from the group consisting of alkoxysilanes having an epoxy group and hydrolysates thereof, and alkoxysilanes having an amino group and hydrolysates thereof, (7) The surface treatment liquid as described.
(9) A method for producing a surface-treated metal, comprising applying the surface treatment liquid according to (7) or (8) to a metal surface and then curing it.

  According to the present invention, a surface-treated metal having excellent contamination resistance can be easily obtained. Moreover, said surface treatment metal can be suitably manufactured by using the surface treatment liquid and manufacturing method of this invention. In particular, the above film has workability and adhesion that can be applied even when a pre-coated steel sheet is used as a metal to be a surface-treated metal substrate.

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

  The surface-treated metal of the present invention is characterized by its surface coating. The surface-treated metal structure has an inorganic skeleton developed into a three-dimensional network structure as the main skeleton, and the main skeleton consists of an inorganic siloxane bond represented by ≡Si-O-Si≡ as the main bond. Yes. By including at least one selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, an aryl group, a carboxyl group, an amino group, and a hydroxyl group in the structure mainly composed of siloxane bonds, it has excellent stain resistance. In addition, a film with excellent workability is formed. Although the reason for this is not clear, the present inventors have found that the film mainly composed of inorganic components inherently has excellent weather resistance and stain resistance, and in addition, in the film, -OH group or Since the hydrolyzable —OR group (R: alkyl group) is contained, the surface is considered to be hydrophilic. In addition, the coating of the present invention includes an organic component including an alkyl group having 1 to 12 carbon atoms in the coating mainly composed of an inorganic component, so that the coating is given flexibility and excellent workability. I think that was able to be secured.

Here, as an alkyl group having 1 to 12 carbon atoms, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a 2-ethylhexyl group, a dodecyl group, etc., an aryl group includes a phenyl group, a tolyl group, A xylyl group, a naphthyl group, etc. are mentioned. Further, the carboxyl group -COOH, amino group -NH _2, hydroxyl points to each -OH.

  Two or more kinds of organic components used in the present invention can be used at the same time. Among them, the main organic group, that is, the organic group having the largest content is an alkyl group having 5 to 12 carbon atoms. It is preferable to use a group or an aryl group, more preferably an alkyl group or aryl group having 6 to 12 carbon atoms, and still more preferably an alkyl group or aryl group having 6 to 10 carbon atoms. . Of these, the organic group that is most preferably used as the organic group of the present invention is a phenyl group, and by combining with a siloxane bond that forms the main skeleton using only the phenyl group, a film having excellent stain resistance can be obtained. Can do. These organic components may be present in the main skeleton or in the side chain. The presence of these organic components in the film is considered to express the excellent characteristics of the film used in the present invention.

Examples of the bond other than the siloxane bond include an ether bond such as —CH ₂ —CH (CH ₂ ) —O—CH ₂ — or an amino bond that becomes a secondary or tertiary amine. Among these, when one or both of an ether bond and an amino bond are present in the main skeleton and / or side chain in the film structure, a film having particularly excellent stain resistance can be obtained. Furthermore, the present inventors believe that the inclusion of the above-described components increases the cross-linking density of the polymer and the dense film contributes to the improvement of stain resistance.

  The thickness of the film used in the present invention varies depending on the required properties or applications, but is preferably 0.05 μm or more and 25 μm or less, more preferably 0.1 μm or more and 20 μm or less, and still more preferably 0 .1 μm or more and 10 μm or less. If the film thickness is too thin beyond these ranges, it is difficult to form a uniform film and exhibit the specified characteristics. On the other hand, if the film is too thick beyond the above range, molding processing is difficult. In many cases, it becomes a film with insufficient adhesion or a film with insufficient adhesion during processing. In addition, it is not preferable to form a thick coating film by a single operation because of the nature of the coating film used as a matrix because it causes cracking and peeling. In the case of forming a film having a thickness greater than or equal to a predetermined thickness, it is preferable to repeat the application and drying (solidification) operations described later.

  Since the inorganic-organic composite film used in the present invention has excellent contamination resistance, it is necessary to form it on the outermost surface of the metal. In this case, as a matter of course, the film is directly formed on the surface of the metal serving as the base material, but there is no problem even if the other film is formed under the present film and the film is formed in multiple layers. Typical examples include the case where an organic coating film, an inorganic-organic composite film, or an inorganic film used in a coated steel sheet is formed. There is no limitation on the composition and components of the lower layer film. As other examples, the film used in the present invention is formed on the surface of a metal subjected to a chromate treatment and a known surface treatment (for example, phosphate treatment) other than the chromate film or a metal other than the chromate. This is the case. The outermost film can be obtained by finally forming an inorganic-organic composite film used in the present invention on the surface of a metal that has been painted or surface-treated.

  The film of the present invention contains Si as a metal component, but as other elements, one or more metal elements selected from B, Al, Ge, Ti, Y, Zr, Nb, Ta, etc. Can be added. Of these, Al, Ti, Nb, and Ta show catalytic action to complete solidification of the film at low temperature or in a short time when these metal alkoxides are added to the system using acid as a catalyst. Is. When these metal alkoxides are added using an acid as a catalyst, the ring-opening speed of the epoxy is increased, so that the film can be cured at a low temperature or in a short time. A particularly frequently used metal is Ti, and Ti alkoxides such as Ti-ethoxide and Ti-isopropoxide are used as raw materials. In addition, since the alkali resistance of the film is remarkably improved in the system to which Zr is added, it is preferably used in applications that require alkali resistance. These metal elements may be substituted with Si to form —O—M—O— bonds, or may have a certain size, for example, in the form of particles, There is no particular problem with the presence form in the film.

  The metal used as the base material of the surface-treated metal of the present invention is not limited in any way, including the material, shape, presence / absence of processing, and final product (shape), and any material is preferably used. can do. For example, steel materials, stainless steel, titanium, aluminum, aluminum alloys, or those obtained by plating these materials can be suitably used regardless of the material. In addition, molded products such as thick plates, thin plates, pipes (pipes), shaped steel, rods, wire rods, etc. can be suitably used regardless of the shape and presence / absence of processing. Among them, particularly preferable metals include stainless steel plates, titanium plates, aluminum plates, aluminum alloy plates, plated metal plates obtained by plating them, or coated steel plates on which organic coatings are formed. Examples of the plated steel sheet include galvanized steel sheet, zinc-iron alloy plated steel sheet, zinc-nickel alloy plated steel sheet, zinc-chromium alloy plated steel sheet, zinc-aluminum alloy plated steel sheet, aluminum-plated steel sheet, zinc-aluminum-magnesium alloy plating. Examples include steel plates, zinc-aluminum-magnesium-silicon alloy plated steel plates, aluminum-silicon alloy plated steel plates, galvanized stainless steel plates, and aluminum plated stainless steel plates. Examples of the stainless steel plate include a ferritic stainless steel plate, a martensitic stainless steel plate, and an austenitic stainless steel plate. The thickness of the stainless steel plate ranges from a thickness of about several tens of mm to a so-called stainless steel foil that is thinned to about 10 μm by rolling. The surface of the stainless steel plate and the stainless steel foil may be subjected to a surface treatment such as bright annealing or buffing. As the aluminum alloy plate, JIS 1000 series (pure Al series), JIS 2000 series (Al-Cu series), JIS 3000 series (Al-Mn series), JIS 4000 series (Al-Si series), JIS 5000 series (Al- Mg series), JIS6000 series (Al-Mg-Si series), JIS7000 series (Al-Zn series), and the like.

  The surface-treated metal of the present invention can be used as a material, but can be suitably used even in a state of being processed into parts. There are no particular restrictions on the parts, and it is suitable for use in building materials such as the outer wall of a house and sizing, and for home appliances such as outdoor units for air conditioners and housings (outer plates) for water heaters. Can do.

  A surface treatment solution for suitably producing the surface-treated metal of the present invention includes a tetraalkoxysilane, an alkoxysilane having an alkyl group having 1 to 12 carbon atoms and a hydrolyzate thereof, an alkoxysilane having an aryl group, and its It is the liquid which has as a main component 1 or more types selected from the group which consists of a hydrolyzate.

  Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Examples of the alkoxysilane having an alkyl group having 1 to 12 carbon atoms include methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane. , Decyltriethoxysilane and the like. Examples of the alkoxysilane having an aryl group include phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane. The surface treatment liquid contains, as a main component, the above-described silane compound, a hydrolyzate thereof, or a polymer obtained by polymerization or condensation reaction thereof.

  By using these components, the main bond of the main skeleton used in the present invention is a siloxane bond, and at least selected from an alkyl group having 1 to 12 carbon atoms, an aryl group, a carboxyl group, an amino group, or a hydroxyl group. An inorganic-organic composite film containing one organic group can be easily obtained. In addition, by using the above components, the ratio of the inorganic component and the organic component in the composite film can be easily changed, and the kind and amount of the organic component introduced into the film can be easily controlled. it can. That is, the inorganic component can be increased according to the properties required for the coating, or conversely, the organic component can be increased, and the kind of the organic component to be added is also appropriately selected according to the required properties. can do.

  The surface treatment liquid used in the present invention can further contain an alkoxysilane having an epoxy group or an alkoxysilane having an amino group. Examples of the alkoxysilane having an epoxy group include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, and γ-glycidoxypropyltributoxysilane. , 3,4-epoxycyclohexylmethyltrimethoxysilane, 3,4-epoxycyclohexylmethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltri Ethoxysilane or the like is preferably used, and γ-glycidoxypropyltriethoxysilane is particularly preferably used from the viewpoint of easy handling and reactivity. Examples of the alkoxysilane having an amino group include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, (β-aminoethyl) -β-aminopropyltrimethoxysilane, and (β-aminoethyl) -β-amino. Propylmethyldimethoxysilane, (β-aminoethyl) -γ-aminopropyltrimethoxysilane and the like are preferably used, and aminopropyltriethoxysilane is particularly preferably used from the viewpoint of ease of handling. These alkoxysilanes, like the above-mentioned alkoxysilanes, may be polymerized in the surface treatment solution in which all or part of the alkoxy groups are hydrolyzed, or they undergo polymerization or condensation reactions. .

  An advantage of blending these alkoxysilanes having an epoxy group and alkoxysilanes having an amino group is that adhesion with a metal as a base material and contamination resistance are improved. Although the details have not been clarified for this reason, the present inventors can form a strong bond that contributes to adhesion with the base metal by adding an epoxy group or an amino group. It is presumed that the crosslink density of polymers and polymers increases. Another advantage of using the above compound for the purpose of blending an alkoxysilane having an epoxy group or an alkoxysilane having an amino group is that the hydrolyzable functional group in the molecule is the same as the essential component described above. This is because the above-described components can be easily incorporated into the structure of the main skeleton by hydrolysis and condensation polymerization together with the essential components because they have groups. The above components are desirably incorporated into the structure of the main skeleton, but are not necessarily incorporated into the structure, and may be present alone. For example, the above component may form a polymer material different from the main skeleton.

  Further, in the surface treatment liquid of the present invention, an alkoxide of a metal component other than tetraalkoxysilane can be used as an additive as necessary. In particular, when at least one metal alkoxide selected from Ti, Al, Ta, or Nb is added and acetic acid is used as an acid catalyst, the ring opening rate of the epoxy group is increased, so that the temperature is reduced for a short time. The effect of curing is particularly great. In the metal alkoxide other than alkoxysilane, all or part of the alkoxy group may be hydrolyzed. Further, the surface treatment liquid of the present invention may contain at least one of a zirconium compound, for example, a zirconium alkoxide, a hydrolyzate thereof, or a zirconium oxide (zirconia) sol, if necessary. This component is a component having an action of improving the alkali chemical resistance of the surface treatment liquid mainly composed of silica used as the coating liquid of the present invention. The mechanism by which the alkali chemical resistance is improved by the addition of this component has not necessarily been clarified. However, the present inventors have replaced the silica constituting the siloxane bond with Zr to produce silica. It is thought that it is because it is stabilized against alkali by forming a network centering on zirconium.

  The surface treatment liquid used in the present invention further includes coloring pigments, moisture-resistant pigments, catalysts (for example, acidic catalyst, basicity) for the purpose of improving the design properties, corrosion resistance, abrasion resistance, catalytic function, etc. of the coating film. Catalyst), rust preventive pigment, metal powder, high-frequency loss agent, aggregate and the like can be added. Examples of the pigment include oxides such as Ti and Al, composite oxides, metal powders such as Zn powder, and Al powder in addition to the compounds described above. As the rust preventive pigment, it is preferable to use non-chromic pigments such as calcium molybdate, calcium phosphomolybdate, and aluminum phosphomolybdate that do not contain environmental pollutants. Moreover, Zn-Ni ferrite is mentioned as a high frequency loss agent, A potassium titanate fiber etc. are mentioned as an aggregate.

  Moreover, an acid catalyst can be added to the surface treatment liquid used in the present invention as necessary. Examples of the acid catalyst include organic acids such as acetic acid, formic acid, maleic acid, and benzoic acid, and inorganic acids such as hydrochloric acid and nitric acid. Acetic acid is particularly preferably used. By using an acid as a catalyst, the alkoxysilane used as a raw material takes a polymerization state suitable for film formation. In addition, when acetic acid is used as a catalyst, ring opening of the epoxy group is promoted, and the temperature is low. This is because the effect of short-time curing is increased.

  Further, as an additive, a leveling effect agent, an antioxidant, an ultraviolet absorber, a stabilizer, a plasticizer, a wax, an additive type ultraviolet stabilizer and the like can be mixed and used. Further, if necessary, a resin-based paint such as a fluororesin, a polyester resin, and a urethane resin may be included as long as the heat resistance of the film is not impaired. These additives may be used alone or in combination of two or more. If necessary, inorganic or metal particles other than zirconia sol, color pigments and dyes can be added.

  The surface treatment liquid of the present invention is a group consisting of tetraalkoxysilane, alkoxysilane having an alkyl group having 1 to 12 carbon atoms, and alkoxysilane having an aryl group in an organic solvent capable of uniformly dispersing and dissolving the solute. Hydrolysis is performed after at least one selected alkoxysilane is mixed with an alkoxysilane having an epoxy group and an acid catalyst, if necessary, to open the epoxy group, and finally, an amino group is added. It can be prepared by adding an alkoxysilane containing. As the organic solvent to be used, for example, various alcohols such as methanol, ethanol, propanol and butanol, and aromatic organic solvents such as acetone, benzene, toluene, xylene and ethylbenzene are used alone or in combination. Is preferred.

  The prepared surface treatment liquid can be used after diluting with an organic solvent or water so as to match the required film thickness. The dilution is usually performed so that the film thickness obtained by one coating is in the range of 0.2 to 5 μm. Moreover, you may form the coating film of the thickness more by multiple times of coating. This film thickness range (0.2 to 5 μm) is an approximate measure for obtaining a healthy film. On the other hand, the alcohol used as a solvent or the alcohol produced by hydrolysis can be applied after being distilled off under normal pressure or reduced pressure.

  The base metal is coated by dip coating, spray coating, bar coating, roll coating, spin coating, or the like. The surface coating used in the present invention exhibits good adhesion even if the above-mentioned various base materials are not pretreated, but can be pretreated before application as required. Typical pretreatments include pickling, alkali degreasing, chromate treatment, non-chromate treatment, chemical conversion treatment, grinding, polishing, blasting, etc., which can be performed alone or in combination as necessary. .

  The film used in the present invention can be cured by allowing it to stand at room temperature. However, when allowed to stand at room temperature, it takes a long time for the film to have a practical hardness, so it is desirable to heat cure. When the film is cured by heating, it is preferable to perform a heat treatment for about 1 hour to several seconds in a temperature range of 150 ° C. to 400 ° C. In general, when the heat treatment temperature is high, the film can be cured in a short heat treatment time, and when the heat treatment temperature is low, a long treatment time is required. When sufficient temperature or time cannot be applied for drying or heat treatment, it is preferable to perform aging at room temperature for 1 to 5 days as necessary after drying, solidification or baking solidification. By this operation, the hardness of the coating film can be increased immediately after the formation of the coating film.

  Hereinafter, the present invention will be specifically described by way of examples.

  Γ-glycidoxypropyltriethoxysilane (GPTES), titanium tetraethoxide (TE), phenyltriethoxysilane (PhTES), and tetraethoxysilane (TEOS) blended in the proportions shown in Table 1-1 are sufficiently stirred. Then, hydrolysis was performed under acidic conditions using distilled water diluted with ethanol. Next, aminopropyltriethoxysilane (APTES) was added thereto, followed by hydrolysis using a distilled water / ethanol mixed solution to prepare a surface treatment liquid mainly composed of an inorganic-organic composite. A sufficient amount of water was used for the hydrolysis, and the surface treatment solution was prepared so that the solid concentration when dried at 150 ° C. was 10% by mass.

  As the steel sheet to be coated, a pre-coated steel sheet in which a non-chromated galvanized steel sheet was coated with a melamine-crosslinked polyester film with a thickness of about 15 μm as an undercoat or topcoat was used. After the surface treatment solution prepared above is applied to a steel plate with a bar coater, heat treatment is performed at a maximum temperature of 230 ° C. using a temperature rise condition such that the plate temperature becomes 230 ° C. after 50 seconds, and the surface treatment has a stain resistant coating. A steel plate was obtained. The thickness of the formed film was about 5 μm. As a comparative example, the above-mentioned precoated steel sheet (the outermost surface was a melamine-crosslinked polyester film) was used.

  The contamination resistance test was conducted by the following method. First, (1) an outdoor steel plate exposure test was conducted to evaluate rain pollution and dust contamination. (2) In the exposure test of (1), it may take a long time for the effect to appear, so as a simple evaluation method, contaminants (black magic, red magic, curry paste) on the surface of the coated steel sheet After 24 hours, the contaminants were wiped off, and the amount of contaminants that could not be removed (the traces) was evaluated. The obtained contamination resistance test results are shown in Table 1-2. The test results were evaluated in four stages: ◎ → ○ → △ → ×. The criteria for each evaluation are shown in Table 2. From this result, it was found that the surface-treated metal of this example had excellent contamination resistance. Although not shown in the table, when the 2T bending test was performed to test the bending workability, no cracking or peeling was observed on all surface-treated steel sheets including the comparative example, and excellent bending It had processability. Judging comprehensively from these results, it was found that the surface-treated steel sheet of the present invention was excellent in stain resistance, and also excellent in bending workability and adhesion during processing.

As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

Claims (9)

  As the outermost surface layer, at least one organic compound selected from the group consisting of alkyl groups, aryl groups, carboxyl groups, amino groups, and hydroxyl groups having a main bond of the main skeleton of siloxane bonds and having 1 to 12 carbon atoms A surface-treated metal comprising an inorganic-organic composite film containing a group.   The surface-treated metal according to claim 1, wherein the organic group contained in the film is a phenyl group.   3. The method according to claim 1, wherein either one or both of an ether bond and an amino bond are included in one or both of the main skeleton and the side chain of the inorganic-organic composite. Surface treatment metal.   The surface-treated metal according to claim 1, wherein the base metal used as a base is a metal plate.   The metal plate is one type selected from the group consisting of a steel plate, a stainless steel plate, a titanium plate, an aluminum plate, an aluminum alloy plate, and a plated metal plate plated on each metal plate. 5. The surface-treated metal according to 4.   The surface-treated metal according to claim 4 or 5, wherein the metal plate is a painted metal plate having an organic coating film. With tetraalkoxysilane;
One or more selected from the group consisting of an alkoxysilane having a C 1-12 alkyl group and a hydrolyzate thereof, and an alkoxysilane having an aryl group and a hydrolyzate thereof;
A surface treatment liquid comprising at least   [8] The method according to claim 7, further comprising at least one selected from the group consisting of an alkoxysilane having an epoxy group and a hydrolyzate thereof, and an alkoxysilane having an amino group and a hydrolyzate thereof. Surface treatment liquid. A method for producing a surface-treated metal, comprising applying the surface treatment liquid according to claim 7 or 8 to a metal surface, followed by curing.