JP6248270B1 - Process for producing anti-rust film forming agent for metal to be processed and metal to be processed with anti-rust film. - Google Patents

Abstract

An object of the present invention is to provide a rust preventive film forming agent for a metal to be processed and a method for producing a metal to be processed with a rust preventive film, which can stably form a film having high corrosion resistance and good adhesion to an overcoat film. To do. (A) One or more selected from the group consisting of trivalent chromium, Mo, W, V, Nb, Ta, Ti, Zr, Ce, Co, Ni, Fe, Al, Mn and alkaline earth metals , (B) an inorganic colloid whose surface is modified with one or more selected from the group consisting of metal alkoxides and silane coupling agents, (C) one or more selected from the group consisting of chloride ions, sulfate ions and nitrate ions A rust preventive film forming agent for a metal to be treated, which contains and has a pH of 1.5 to 4. [Selection figure] None

Description

  The present invention relates to a rust preventive film forming agent for various metals to be processed and a method for producing a metal to be processed with a rust preventive film. In particular, it relates to a method for producing zinc or a zinc alloy, a rust preventive film forming agent for a metal material such as iron plated with these, and a metal to be treated with a rust preventive film.

  In general, zinc or zinc-based alloy plating (hereinafter referred to as zinc plating) is most widely used as a rust prevention method for ferrous materials and parts. However, when a galvanized iron-based material / part is used as it is, white rust, which is rust of zinc, is immediately generated, and therefore a protective film is generally further formed. A chromate film treatment is generally used as a protective film usually applied to galvanizing, and the chromate film treatment is further classified into three types: electrolytic chromate treatment, coating chromate treatment, and reactive chromate treatment. The chromate treatment is applied not only to zinc but also to aluminum, cadmium, magnesium and the like.

  Chromate films are widely used because they are inexpensive and can easily provide practical corrosion resistance. However, all chromate treatment uses harmful hexavalent chromium, and hexavalent chromium eluted from treated products as well as treated products has an adverse effect on the human body and the environment. It has come to be regulated. As an alternative technique of hexavalent chromate, there is a corrosion-resistant film using trivalent chromium, and various inventions have been filed.

For example, Japanese Patent Application Laid-Open No. 61-587 (Patent Document 1) describes a treatment liquid containing trivalent chromium ions, silicates, fluorides, and acids. Corrosion resistance is not sufficient compared to conventional chromate. Moreover, since this composition uses fluoride, there is an environmental problem.
Japanese Patent No. 4493930 (Patent Document 2) describes a method of processing using a processing liquid containing a trivalent chromium salt and a metal salt such as an organic acid or cobalt, and it is said that good corrosion resistance can be obtained. However, since the trivalent chromium concentration is high and the processing temperature is also high, it is difficult to stably form a dense film, and stable corrosion resistance cannot be obtained. In addition, a composition using an organic acid has poor stability, and has a problem that the appearance of the treatment and the pH of the liquid change in several days to several weeks, and that wastewater treatment becomes difficult.
In Japanese Patent No. 4529208 (Patent Document 3), a chemical conversion treatment solution comprising a trivalent chromium compound and a titanium compound, a tungsten compound and a silicon compound, and in Japanese Patent No. 3332374 (Patent Document 4), trivalent chromium ions and oxalic acid are used. Although a treatment liquid containing cobalt and a silicon compound is described, there are large variations in practical use such as a case where the appearance of the treatment becomes cloudy or the corrosion resistance may be insufficient.
As described above, the prior art has problems of insufficient processing appearance and stability of corrosion resistance and low cost performance (performance obtained with respect to processing conditions).
Here, the present inventors disclosed in Japanese Patent No. 4090780 (Patent Document 5) a rust preventive film forming agent capable of solving the above-described problems of the prior art. However, when an overcoat film is applied to a film obtained from a treatment liquid containing a silicon compound, the corrosion resistance is improved, but depending on the type of overcoat, the adhesion is insufficient and the overcoat film peels off. Has been confirmed as a problem.

Japanese Patent Laid-Open No. 61-587 Japanese Patent No. 4493930 Japanese Patent No. 4529208 Japanese Patent No. 3332374 Japanese Patent No. 4090780

  The object of the present invention is to stably produce a film having uniform and good appearance and corrosion resistance without using harmful hexavalent chromium in forming a protective film on the surface of metal, particularly zinc or zinc alloy. More specifically, it has a higher corrosion resistance than the rust-preventing film formed by the rust-preventing film forming agent disclosed in the above-mentioned Japanese Patent No. 4090780, and also stabilizes the film having good adhesion to the overcoat film. It is providing the manufacturing method of the rust preventive film formation agent of the to-be-processed metal formed, and a to-be-processed metal with a rust preventive film.

As a result of intensive studies by the present inventors, it has been found that the above-mentioned problems can be solved by blending an inorganic colloid mainly composed of various metals and modified with a metal alkoxide and a silane coupling agent.
That is, the present invention is (A) selected from the group consisting of trivalent chromium, Mo, W, V, Nb, Ta, Ti, Zr, Ce, Co, Ni, Fe, Al, Mn, and alkaline earth metal 1 One or more species selected from the group consisting of (C) chloride ion, sulfate ion and nitrate ion, (B) the inorganic colloid modified with one or more species selected from the group consisting of metal alkoxide and silane coupling agent A rust preventive film forming agent for a metal to be treated, which contains the above and has a pH of 1.5 to 4.
The inorganic colloid is preferably colloidal silica.
Further, (D) a stabilizer which is at least one selected from the group consisting of surfactants, organic acids, hydrogen peroxide, ureas, aliphatic amines, and ammonium salts can be included.
Moreover, this invention is a manufacturing method of the to-be-processed metal with an antirust film characterized by forming an antirust film by making the said antirust film forming agent contact a to-be-processed metal.
Moreover, after forming a rust preventive film by making the said rust preventive film forming agent contact with a to-be-processed metal, the liquid composition which further contains 1 or more types in the group which consists of Si, resin, wax, and solid lubricant And can be overcoated.
In the present invention, the metal to be treated can be zinc, aluminum, magnesium, copper, nickel, chromium, iron, tin, and alloys thereof.
Further, the present invention provides a metal to be treated comprising a combination of the above-mentioned metal rust preventive film forming agent and a liquid composition containing one or more members selected from the group consisting of Si, resin, wax, and solid lubricant. It is a combination of the liquid composition for forming a rust preventive film.

The rust preventive film obtained by using the rust preventive film forming agent of the present invention not only provides corrosion resistance equal to or higher than that of conventional colored chromate and trivalent chromium chemical conversion film, but also provides a very uniform appearance. . In addition, when an overcoat film was applied, the peeling that had been a problem in the past was also improved, enabling further improvement in corrosion resistance, designability, and control of the coefficient of friction.
Furthermore, the rust preventive film obtained by using the rust preventive film forming agent of the present invention can be a practical one to which the ability to suppress the corrosion resistance at the time of film damage is added. This ability to suppress the deterioration of corrosion resistance suppresses the generation of rust when the film is damaged by, for example, stepping stones in automobile parts and the like, and is a very important performance in industry. In an actual production line, bolts and other items of moderate weight may drop or collide with each other (coincidence during processing), resulting in many scratches. According to the present invention, it is possible to greatly improve the ability to suppress a decrease in corrosion resistance when the film is damaged as compared with the prior art.

  According to the present invention, an anticorrosive film forming agent for a metal to be processed and a metal to be processed with an anticorrosive film that stably forms a film having high corrosion resistance and good adhesion with an overcoat film. A method can be provided.

(Metal to be treated)
Examples of the metal to be treated of the present invention include zinc, aluminum, magnesium, copper, nickel, chromium, iron, tin, and alloys thereof. The rust preventive film forming agent of the present invention particularly effectively acts on zinc plating, zinc alloy plating, zinc die cast, aluminum, aluminum alloy including die cast, magnesium, and magnesium alloy including die cast.

(Rust preventive film forming agent)
The anticorrosive film-forming agent of the present invention comprises (A) a group consisting of trivalent chromium, Mo, W, V, Nb, Ta, Ti, Zr, Ce, Co, Ni, Fe, Al, Mn, and an alkaline earth metal. One or more selected from (B) an inorganic colloid modified with one or more selected from the group consisting of metal alkoxides and silane coupling agents, (C) from the group consisting of chloride ions, sulfate ions and nitrate ions Contains one or more selected, and has a pH of 1.5-4.

  (A) One or more selected from the group consisting of trivalent chromium, Mo, W, V, Nb, Ta, Ti, Zr, Ce, Co, Ni, Fe, Al, Mn and alkaline earth metals are supplied. The method is not particularly specified, and in addition to inorganic salts such as chlorides, sulfates and nitrates, other necessary components such as acid ions can be supplied by supplying organic acid salts, oxoacids, oxoacid salts, etc. This is convenient because it can be used, and particularly sulfate compounds and nitrate compounds have good corrosion resistance. (A) One or more concentrations selected from the group consisting of trivalent chromium, Mo, W, V, Nb, Ta, Ti, Zr, Ce, Co, Ni, Fe, Al, Mn, and alkaline earth metal are: 0.01-100 g / L, preferably 0.01-50 g / L, more preferably 0.01-10 g / L.

(B) As the inorganic colloid whose surface is modified with one or more selected from the group consisting of metal alkoxides and silane coupling agents, various metal oxides can be used. In particular, the primary particle diameter is preferably 1 to 200 nm, preferably Is preferably an aqueous dispersion colloidal solution in the range of 1 to 100 nm, more preferably 1 to 50 nm. One or more selected from the group consisting of metal alkoxides and silane coupling agents are 0.001 to 10 g / L, preferably 0.01 to 5 g / L, but if further added, metal alkoxides and silane couplings If the surface modification with the agent is 1 to 50%, preferably 1 to 30%, the surface of the inorganic colloid, a more excellent corrosion-resistant film can be obtained stably. If the amount is less than this range, the effect cannot be obtained. On the other hand, if the amount is excessive, the electric repulsion of the inorganic colloid is impaired, or the excess silane coupling agent reacts to cause aggregation or gelation. (B) The concentration of the inorganic colloid whose surface is modified with one or more selected from the group consisting of metal alkoxides and silane coupling agents is 0.01-100 g / L, preferably 0.1-50 g / L, more preferably Can be 0.1-30 g / L.
An inorganic colloid whose surface is modified with at least one selected from the group consisting of metal alkoxides and silane coupling agents can be obtained by mixing and condensing an aqueous solution obtained by hydrolyzing metal alkoxides and silane coupling agents with an inorganic colloid solution. However, in order to obtain a more stable condensate, it is desirable to stir for 1 hour or more.

  Here, various metal alkoxides and silane coupling agents can be used. For example, when an overcoat film containing a resin is applied, if it is classified according to functional groups reactively bonded to an organic material, vinyl silane, epoxy silane, amino silane, methacryloxy silane, and the like can be given as representative examples of these silane coupling agents. 1 type (s) or 2 or more types can be used. Silane coupling agents other than the above silane coupling agents can also be used within the scope of achieving the object of the present invention.

  (C) As a supply source of chloride ions, sulfate ions and nitrate ions, inorganic acid salts such as hydrochloric acid, sulfuric acid, nitric acid, sodium chloride, sodium sulfate, sodium nitrate and the like can be used. Various anions contained in chromium compounds and zirconium compounds such as chromium sulfate, chromium chloride, chromium nitrate, zirconium sulfate, zirconium chloride, and zirconium nitrate can also be used as a supply source. If it is a compound of a chloride ion, a sulfate ion, and a nitrate ion, substances other than the above can also be used as a supply source of a chloride ion, a sulfate ion, and a nitrate ion. One kind or two or more kinds of chloride ions, sulfate ions and nitrate ions can be used. The concentration of chloride ions, sulfate ions and nitrate ions is preferably 0.001 to 200 g / L, more preferably 0.01 to 100 g / L, and even more preferably 0.1 to 100 g / L. If the concentration of chloride ion, sulfate ion and nitrate ion is within the above range, a good chemical conversion film can be formed, and uniform treatment appearance, corrosion resistance, and adhesion to the overcoat film can be obtained stably. When the concentration of chloride ion, sulfate ion and nitrate ion is lower than 0.001 g / L, the corrosion resistance and the adhesion between the overcoat film are reduced, and when it exceeds 200 g / L, the cost merit is reduced and the processing appearance is uneven. Is likely to occur.

  Moreover, adding a stabilizer to the rust-preventing film-forming agent of the present invention is effective for stabilizing the corrosion resistance and design properties. As the stabilizer, 0.01 to 100 g / L, preferably 0.01 to 50 g / L of a surfactant, an organic acid, hydrogen peroxide, urea, an aliphatic amine, and an ammonium salt are selected. Liquid composition stabilizers are preferred.

  A rust-proof film is formed by contacting the liquid composition with zinc or zinc-based alloy plating. The preferable conditions for forming the film include a processing time of 15 to 120 seconds, a processing temperature of 15 to 40 ° C., and a pH of 1.5 to 4.

  An overcoat film may be formed from a liquid composition containing at least one selected from the group consisting of Si, resin, wax, and solid lubricant on the rust-proof film obtained from the liquid composition. The Si content for forming the overcoat film is 0.01 to 500 g / L, preferably 1 to 300 g / L. If the amount is insufficient, the effect cannot be obtained. May occur. As the silicon compound, sodium silicate, potassium silicate, lithium silicate, and colloidal silica are preferable.

  There is no limitation in particular as resin, Acrylic resin, olefin resin, alkyd resin, urea resin, epoxy resin, melamine resin, fluororesin, polyethylene, polypropylene, polyvinyl chloride, polystyrene, methacrylic resin, phenol resin, polyester resin, silicon resin Resins such as polyurethane, polyamide, and polycarbonate can be used. It is necessary to select an appropriate concentration depending on the corrosion resistance and appearance (gloss, liquid pool, unevenness), etc., and a high corrosion resistance of 1 to 800 g / L, preferably 10 to 500 g / L tends to be obtained.

  The wax is not particularly limited, and natural waxes typified by carnauba wax and petroleum wax, synthetic waxes typified by polyethylene wax and polypropylene wax, and semi-synthetic waxes typified by amide wax and montan wax are preferable. Also, solid lubricants such as PTFE fine particles, molybdenum disulfide, organic molybdenum, and graphite can be used. Although it cannot be specified unconditionally depending on the required properties (friction coefficient, etc.), it can generally be used within a range of 0.01 to 200 g / L with little influence on other properties.

  Conditions for forming an overcoat film with a liquid composition containing at least one of the group consisting of Si, resin, wax, and solid lubricant are, for example, a processing time of 1 to 60 seconds, preferably 10 to 40 seconds, The treatment temperature is 5 to 80 ° C., preferably 15 to 60 ° C. If it is further added, it is desirable that the temperature is higher than the glass transition point of the resin used. The treatment pH can be used as long as the stability of the resin used can be maintained, but is generally 7.5 to 14.

Hereinafter, the present invention will be described with reference to examples and comparative examples.
The test piece (M8 flange bolt) is degreased and subjected to appropriate pretreatments such as acid activity, and then galvanized (Zn) and zinc-iron alloy plated (by using Nippon Kasei Chemical Co., Ltd.) After applying either Zn / Fe) or zinc-nickel alloy plating (Zn / Ni) to a plating film thickness of 8 to 9 μm, it is immersed in the rust preventive film forming agent shown in Tables 1 to 3, and then washed with water. Drying was performed to form a rust preventive film. In the case of performing an overcoat treatment, after forming a rust preventive film, it was immersed in the liquid compositions shown in Tables 2 and 3 and then dried at 80 ° C. for 10 minutes in a centrifugal dryer. In the table, Nissan Chemical Snow Co., Ltd. Snowtex 20 as colloidal silica, Nissan Chemical Co., Ltd. alumina sol 520 as titanic sol, Fuji-Titanium Industry Co., Ltd. DC-Ti, Zirconia sol as first rare element chemical industry ( ZSL-10L made by Co., Ltd. was used. Modification of the inorganic colloid with the metal alkoxide or silane coupling agent was performed by mixing an aqueous solution obtained by hydrolyzing the metal alkoxide or silane coupling agent shown in Tables 1 to 3 and stirring the mixture for 1 hour. As a comparative example, a rust preventive film was formed using a conventional composition and a composition containing no metal alkoxide or silane coupling agent. And in the comparative example 2 and the comparative example 8, without passing through the process which modifies the inorganic colloid surface using a metal alkoxide or a silane coupling agent, 3-glycidoxypropylmethyltrimethoxylane is simply used as a rust preventive film forming agent. A rust preventive film was formed using a composition only with the addition of.

Evaluation of corrosion resistance shows the time when white rust was generated 5% in the salt spray test according to JIS Z 2301. The corrosion resistance at the time of film damage was evaluated in a salt spray test according to JIS Z 2301, after placing a test piece in a plastic bottle and dropping it 10 times from a height of 1 m.
The coefficient of friction was measured in a tightening test according to JIS B 1084. The number of samples was 10, the average value and standard deviation were calculated, and the variation was evaluated.
The adhesion of the overcoat film was evaluated by the following procedure. Using a cutter knife on the test surface, make 11 cuts at 1 mm intervals that reach the substrate, and then draw another 11 by changing the 90 ° direction. The cellophane tape is strongly pressed against the cut film surface, keeping the end of the tape perpendicular to the film surface and peeling off instantaneously. The evaluation is A when no lattice is peeled off, B when the film is partially or completely peeled along the cut line (less than 15%), and C when the film is peeled off 15% or more. It was.

(Evaluation)
From the results of the examples, (A) 1 selected from the group consisting of trivalent chromium, Mo, W, V, Nb, Ta, Ti, Zr, Ce, Co, Ni, Fe, Al, Mn, and alkaline earth metal One or more species selected from the group consisting of (C) chloride ion, sulfate ion and nitrate ion, (B) the inorganic colloid modified with one or more species selected from the group consisting of metal alkoxide and silane coupling agent By forming a rust preventive film forming agent containing the above and having a pH of 1.5 to 4, excellent corrosion resistance, corrosion resistance at the time of film damage, coefficient of friction with little variation, and good adhesion to the overcoat film It was confirmed that On the other hand, from the result of the comparative example, it was confirmed that even if any one of the components (A) to (C) is insufficient, the above effect cannot be obtained. In particular, in Comparative Examples 2 and 8, since the silane coupling agent is simply added and the step of modifying the surface of the inorganic colloid is not performed, the effect on the corrosion resistance is not obtained in Comparative Example 2, and Comparative Example 8 is obtained. No effect on corrosion resistance and adhesion to the overcoat film was obtained.

Claims (7)

(A) one or more selected from the group consisting of trivalent chromium, Mo, W, V, Nb, Ta, Ti, Zr, Ce, Co, Ni, Fe, Al, Mn and alkaline earth metal,
(B) an inorganic colloid whose surface is modified with one or more selected from the group consisting of metal alkoxides and silane coupling agents,
(C) containing one or more selected from the group consisting of chloride ions, sulfate ions and nitrate ions,
A rust preventive film forming agent for a metal to be treated, having a pH of 1.5 to 4.   The said metal colloid is colloidal silica, The rust preventive film formation agent of the to-be-processed metal of Claim 1 characterized by the above-mentioned.   Further comprising (D) a stabilizer which is at least one selected from the group consisting of surfactants, organic acids, hydrogen peroxide, ureas, aliphatic amines, and ammonium salts. A rust preventive film forming agent for a metal to be treated.   A method for producing a metal to be treated with a rust preventive film, wherein the rust preventive film is formed by bringing the rust preventive film forming agent according to any one of claims 1 to 3 into contact with the metal to be treated.   After forming a rust preventive film by making the rust preventive film forming agent according to any one of claims 1 to 3 contact a metal to be processed, one of the group consisting of Si, resin, wax, and solid lubricant The manufacturing method of the to-be-processed metal with a rust preventive film characterized by making it contact with the liquid composition containing a seed | species or more, and overcoating.   The method for producing a metal to be treated with a rust preventive film according to claim 4 or 5, wherein the metal to be treated is zinc, aluminum, magnesium, copper, nickel, chromium, iron, tin, or an alloy thereof.   It consists of a combination of a rust preventive film-forming agent for a metal to be treated according to any one of claims 1 to 3 and a liquid composition containing one or more members selected from the group consisting of Si, resin, wax and solid lubricant. A combination of liquid compositions for forming a rust-preventing film on a metal to be treated.