JP3765814B2 - Ground treatment solution for metal coating and coating method - Google Patents

Description

  The present invention relates to a base coating solution for metal coating and a coating method.

  Conventionally, in a wide range of industrial products such as home appliances, acoustic products, electronic products, communication equipment, precision equipment, optical equipment, transportation equipment, leisure / sports equipment, ornaments, furniture, building materials, metal parts, metal Parts made by metal plating on base materials such as materials and synthetic resins are often used. Since metal is easily corroded by atmospheric oxygen, sulfur oxides, rainwater, seawater, etc., the metal surface is coated in order to improve its corrosion resistance and prevent corrosion.

  And in order to improve the adhesion between the metal surface and the coating film formed by coating, and also to improve the corrosion resistance of the metal surface, the metal surface is pretreated (chemical conversion treatment) to form a film. It is common to form a coating film on the top by electrodeposition coating.

  Examples of the metal pre-treatment method include chromate treatment. The chromate treatment is a method of treating a metal with a metal coating ground treatment solution containing a hexavalent chromium compound. By this method, a chromate film excellent in corrosion resistance and adhesion to the coating film is formed on the metal surface. However, the chromate film has a risk of leaching highly toxic hexavalent chromium to the outside. That is, hexavalent chromium is not only used as a causative agent for nasal septal pores, chromium allergy, ulcers, etc., but also has been suspected of having carcinogenicity, and there is a strong movement to restrict or prohibit its use. Metal ions. Furthermore, hexavalent chromium is leached out from the chromate film on the surface of parts such as automobiles and electrical equipment that are left outdoors, resulting in a problem of polluting the environment.

  Examples of the metal coating pretreatment method other than the chromate treatment include a method of treating a metal with a metal coating ground treatment solution containing a phosphate. Phosphate films such as zinc phosphate film and iron phosphate film formed on the metal surface by this method do not have corrosion resistance and adhesion to the film comparable to chromate films. For this reason, for example, by adding a heavy metal such as nickel or a fluoride to a ground treatment solution for metal coating containing phosphate, the corrosion resistance of the phosphate coating, the adhesion to the coating, and the like are improved. (For example, refer to Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4). However, although heavy metals such as nickel are certainly effective in improving the physical properties of phosphate films, similar to hexavalent chromium, restriction or prohibition of use in the future is beginning to be investigated for environmental reasons. . In the current situation where environmental protection is one of the important issues, it is inappropriate to use such a surface treatment solution.

  In addition, the main components of the film are phosphates, metal ion sources such as zinc, manganese and copper salts, and oxidizing agents such as nitrites, chlorates and bromates, which contain nickel. There has also been proposed a phosphate-based surface treatment solution characterized by the absence of the same (for example, see Patent Document 5). However, the film formed by this treatment liquid is effective to some metals, such as steel, zinc, zinc alloy, aluminum, and aluminum alloy, but it has sufficient corrosion resistance and coating for more metal species. It does not give adhesion to the film.

  Thus, for example, the phosphate coating is excellent in corrosion resistance and adhesion to the coating, so that the zinc phosphate coating is particularly effective for iron, zinc and aluminum-based metals. In order to form a thin film, the type of phosphate must be changed depending on the metal species. That is, since there is currently no phosphate-based surface treatment agent capable of forming a film effective for various metals, a surface treatment solution containing a phosphate dedicated to the metal is required for each metal. Therefore, although there is no particular problem in the treatment of parts made of a single type of metal material, a phosphate film having good corrosion resistance and adhesion to the coating film is formed on parts made of multiple types of metal materials. Will require very complicated work.

  On the other hand, when coating a copper alloy, it has been proposed to pretreat the copper alloy with a treatment solution containing an alkali metal phosphate such as trisodium phosphate and an inorganic oxidizing agent such as potassium permanganate (for example, And Patent Document 6). However, the technique of Patent Document 6 forms a coating made of a purple or black metal oxide on a copper alloy with the above treatment liquid, and spraying, dipping, roll coating, brush coating, etc. on the coating, It is intended to form a heat-resistant resin or a resin film containing a heat-resistant resin and a fluororesin, and is not intended to form a coating film by electrodeposition coating. Moreover, Patent Document 6 has no disclosure about the use of a nonionic surfactant together with an alkali metal phosphate and an oxidizing agent and the effects obtained thereby.

  Furthermore, an electroless nickel-phosphorous plating film is applied to the surface of the steel material, phosphates such as phosphoric acid, tripolyphosphoric acid, alkali metal salts of pyrophosphoric acid, hydrogen peroxide, alkali metal salts of persulfuric acid, alkali metal peroxides, peroxides. It has been proposed to improve the corrosion resistance of the electroless nickel-phosphorous plating film by treating with an alkaline aqueous solution containing an oxidizing agent such as an alkali metal salt of manganic acid and an alkali metal hydroxide (for example, see Patent Document 7). . However, Patent Document 7 has no disclosure about the use of a specific surfactant together with a phosphate and an oxidizing agent and the effects obtained thereby. In addition, there is no disclosure about the use of this alkaline aqueous solution for coating pretreatment.

JP 57-152472 A Japanese Patent Publication No.61-36588 Japanese Patent Publication No. 3-191017 Japanese Patent Laid-Open No. 11-264076 JP-A-4-228579 JP-A-10-52667 JP 11-323567 A

An object of the present invention, copper, copper alloy, tin, metal tin alloy, on the metal surface of a chromium or precious metals, it is possible to form a coating having adhesion to the equivalent corrosion resistance and coating and click chromate coating An object of the present invention is to provide a coating surface treatment solution and a coating method using the metal coating surface treatment solution.

The invention, and one or more phosphate selected from (a) phosphoric acid, ammonium salts of pyrophosphoric acid and polyphosphoric acid, sodium salt, potassium salt and calcium salt,
(B) One or more of hydrogen peroxide, persulfate, nitrate and permanganate, and one or two selected from oxyacids, oxides and sulfates of manganese, cerium, vanadium and tin an oxidizing agent selected from the above,
(C) and a non-ionic surfactant, remainder Ri Ah with water, copper, copper alloy, tin, tin alloy, metallic paint surface treatment, characterized in that used for the painting surface treatment of chromium or precious metal It is a liquid.

  Furthermore, the ground treatment liquid for metal coating of the present invention comprises 0.1 to 15% by weight (0.1 to 15% by weight) phosphate, 0.01 to 5% by weight (0.01% by weight). % And 5% by weight or less) and a nonionic surfactant 0.005 to 1% by weight (0.005% by weight or more and 1% by weight or less), with the balance being water.

  Furthermore, the metal-treatment ground treatment solution of the present invention is characterized in that the pH is 8 to 11 (8 or more and 11 or less).

  Furthermore, the ground treatment liquid for metal coating of the present invention is characterized in that the nonionic surfactant described above is an aliphatic alcohol nonionic surfactant.

In addition, the present invention is to coat the metal surface after treating the surface of the metal that is copper, copper alloy, tin, tin alloy, chromium or noble metal using any of the above-mentioned surface treatment solutions for metal coating. It is the painting method characterized by this.

  Furthermore, the coating method of the present invention is characterized in that the metal surface is coated by an electrodeposition coating method after treating the metal surface with any one of the above-described metal coating ground treatment solutions.

According to the present invention, certain phosphates, including specific oxidizing agent and a nonionic surface active agent as an active ingredient, with the balance being water metallic paint undercoating liquid, copper, copper alloy, tin By pre-treating the surface of a metal that is a tin alloy, chromium or a noble metal, the metal surface does not contain hexavalent chromium or other harmful metals, and has corrosion resistance and adhesion to coating films formed by various paints. An excellent film can be formed. Since a specific phosphate is highly reactive with a metal in the presence of a specific oxidant, a film with very good corrosion resistance and adhesion to the film can be formed on the surface of the metal to be treated. .

Therefore, if the surface of a metal that is copper, copper alloy, tin, tin alloy, chromium or noble metal is treated using the ground coating solution for metal coating of the present invention and subsequently coated, adhesion to the metal surface is improved. A remarkably excellent coating film is formed.

  In the surface treatment solution for metal coating of the present invention, most of the phosphates that are the main components of the film formed on the metal surface are poorly water-soluble, and when phosphate is present using water as a medium, the vicinity of the metal surface Then, it is difficult to form a film alone. For this reason, in the prior art, film formation on the metal surface is promoted by using metal ions such as zinc ions, iron ions, chromium ions, and calcium ions in addition to phosphates. However, when a film is formed in this way, the phosphate groups are likely to bind to other metal ions, so they do not bind firmly to the metal surface, and there are not many active phosphate groups on the film surface. Corrosion resistance and adhesion with paint become insufficient. On the other hand, in the present invention, by causing an oxidizing agent to act on the phosphate, the reaction between the metal surface and the phosphate group is promoted, and the phosphate group is bonded to the metal group on the metal surface. It succeeded in making an acid group fully exist in the film | membrane surface.

  Therefore, the ground treatment liquid for metal coating according to the present invention contains other components such as an oxidizing agent and a nonionic surfactant even though it contains phosphate as a main component of the film. By the action, it is possible to form a film having high corrosion resistance and high adhesion to the coating film, which cannot be obtained with a conventional metal-coating base treatment liquid containing phosphate.

  A film with excellent corrosion resistance and adhesion to the coating film by allowing an oxidizing agent and a nonionic surfactant to act on the surface of the metal to be treated in the process of forming a coating film composed mainly of phosphate. Therefore, even if an oxidizing agent is allowed to act after forming a film composed mainly of phosphate, the desired corrosion resistance cannot be obtained.

In addition, by using the ground treatment solution for metal coating according to the present invention, a film having good corrosion resistance and good adhesion to the coating film can be formed on the surface of the article even if the article is composed of a plurality of metal species. This is very advantageous industrially. Further, the ground coating solution for metal coating of the present invention is effective for pre-coating of copper, copper alloy, tin, tin alloy and chromium. Further, unlike conventional metal-coating ground treatment solutions containing phosphate, it is extremely effective for precious metals such as gold, silver, and palladium.

  According to the present invention, each component acts efficiently by using specific amounts of phosphate, oxidizing agent and nonionic surfactant, which are active ingredients of the base coating solution for metal coating of the present invention, The corrosion resistance of the film formed on the surface of the metal to be treated and the adhesion with the coating film are further improved.

  According to the present invention, by adjusting the pH of the ground coating solution for metal coating of the present invention to a specific range of 8 to 11, the corrosion resistance of the film formed on the surface of the metal to be treated and the adhesion with the coating film are further improved. improves.

  According to the present invention, among the aforementioned nonionic surfactants, the use of an aliphatic alcohol-based nonionic surfactant further improves the uniformity of the film formed on the surface of the metal to be treated. The excellent corrosion resistance and adhesion to the coating film can be maintained for a longer period of time.

According to the present invention, after treating a metal surface which is copper, copper alloy, tin, tin alloy, chromium or noble metal with the above-described ground coating solution for metal coating of the present invention, the metal surface is coated, preferably electrodeposited. By performing the coating, it is possible to form a coating film on the metal surface that is excellent in corrosion resistance and adhesion to the metal surface, protects the metal from corrosion and the like over a long period of time, and can improve the appearance quality.

The base coating solution for metal coating of the present invention is an aqueous composition containing (a) a phosphate, (b) an oxidizing agent and (c) a nonionic surfactant as active ingredients, and the balance being water. .

  The ground coating solution for metal coating of the present invention preferably has a pH of 8 to 11, more preferably 9 to 10. If the pH is much lower than 8 or significantly higher than 11, the reaction between the phosphate and the metal to be treated may be inhibited, and a film having sufficient corrosion resistance may not be formed.

As the phosphate of component (a), ammonium, sodium, potassium and calcium salts of orthophosphoric acid, pyrophosphoric acid and tripolyphosphoric acid are used. Specific examples include sodium phosphate, calcium phosphate, ammonium phosphate, potassium pyrophosphate, sodium pyrophosphate, sodium tripolyphosphate, and the like. Particularly preferred are normal phosphates having 2 to 3 sodium, potassium or calcium in one molecule, such as sodium phosphate, calcium phosphate, potassium pyrophosphate, sodium pyrophosphate and the like. A phosphate can be used individually by 1 type, or can use 2 or more types together.

  The content of the phosphate in the ground coating solution for metal coating of the present invention is not particularly limited, and is treated with the type of phosphate, the type and content of other components used in combination, and the ground coating solution for metal coating of the present invention. Although it can be appropriately selected from a wide range depending on the type of metal to be used, it is usually 0.1 to 15% by weight, preferably 3 to 10% by weight, based on the total amount of the base coating solution for metal coating of the present invention. If the phosphate content is less than 0.1% by weight, the film formed on the surface of the metal to be treated may be uneven or the film thickness may be too thin, resulting in insufficient corrosion resistance. On the other hand, if it greatly exceeds 15% by weight, the action of the oxidizing agent may be reduced.

The oxidizing agent of component (b), an inorganic oxidizing agent, oxygen acid salts, use one or more selected from the oxides and sulfates. As the inorganic oxidizing agent, using a peroxide Hydrogen, persulfates, nitrates and permanganates. Examples of the persulfate include persulfate alkali metal salts such as potassium persulfate and sodium persulfate, alkaline persulfate earth metal salts such as barium persulfate, and ammonium persulfate . Examples of the nitrate include potassium nitrate, copper nitrate, silver nitrate, and ammonium nitrate . The permanganate, such as permanganic acid alkali metal salts such as potassium permanganate and the like. Oxygen acid salts, the oxides and sulfate, tungsten, vanadium, oxygen acid salts of cerium and tin include oxides and sulfates. Of these, tungsten, oxyacid salts of vanadium and cerium, oxides and sulfates are good preferable. Specific examples include tungstate, vanadate, vanadium pentoxide, cerium sulfate, and the like. Moreover, formation of a film can be further promoted by using one or more inorganic oxidizing agents in combination with one or more selected from oxyacid salts, oxides and sulfates.

  The content of the oxidizing agent in the composition of the present invention is not particularly limited and can be appropriately selected from a wide range depending on the type of oxidizing agent, the type and content of other components used in combination, the type of metal to be treated, etc. Is 0.1 to 5% by weight, preferably 1 to 3% by weight, based on the total amount of the composition of the present invention. If it is less than 0.1% by weight, the reaction between the phosphate and the metal to be treated does not proceed smoothly, and the corrosion resistance of the film may be insufficient. If it greatly exceeds 5% by weight, the oxidant may be self-decomposed and the effect of adding the oxidant may be reduced.

  As the component nonionic surfactant, known ones can be used. For example, aliphatic alcohol nonionic surfactants such as polyethylene glycol and ethylene glycol, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl, etc. Ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester and the like can be mentioned. Among these, aliphatic alcohol-based nonionic surfactants are preferable. A nonionic surfactant can be used individually by 1 type, or can use 2 or more types together.

  The content of the nonionic surfactant in the composition of the present invention is not particularly limited, and is wide depending on the type of nonionic surfactant, the type and content of other components used in combination, the type of metal to be treated, and the like. Although it can be appropriately selected from the range, it is usually 0.005 to 1% by weight, preferably 0.01 to 1% by weight of the total amount of the composition of the present invention. If it is less than 0.005% by weight, the uniformity of the formed film will be insufficient, and in particular, the corrosion resistance of the film may be adversely affected. If it exceeds 1% by weight, salting out of the surfactant occurs, and the effect of adding the surfactant may be reduced.

  The ground coating solution for metal coating of the present invention may contain various additives conventionally used in this field in addition to the above essential components as long as the preferable characteristics are not impaired. Examples of the additive include metal salts such as aluminum, molybdenum and manganese, silane compounds such as polyalkylsiloxane, phosphorus compounds such as alkyl phosphate esters and alkanolamine phosphate, nitrogen compounds such as imidazole, tannic acid, boron Examples thereof include organic acids such as acid, gluconic acid and citric acid. These additives can be used alone or in combination of two or more.

  The base coating solution for metal coating of the present invention is, for example, an appropriate amount of each of the essential components which are a phosphate, an oxidizing agent and a nonionic surfactant, and other additives as required, and the total amount becomes 100% by weight. It can be produced by dissolving or dispersing each component in water according to a known method using an amount of water.

  Common alkali and acid are used for pH adjustment of the ground coating solution for metal coating of the present invention. Examples of the alkali include alkali metal hydroxides such as ammonia water, sodium hydroxide, and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, and alkali metal hydrogen carbonates such as sodium bicarbonate and potassium bicarbonate. Etc. An alkali can be used individually by 1 type, or can use 2 or more types together as needed. Examples of the acid include phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, acetic acid and the like.

The ground treatment liquid for metal coating of the present invention can be suitably used for rust prevention treatment of a metal selected from copper, copper alloy, tin, tin alloy and chromium and a plating film formed containing the metal . Examples of the copper alloy include copper -silver, copper-cadmium, copper-chromium, copper-beryllium, copper-aluminum, and copper-nickel. Examples of tin alloys include tin-nickel, tin-cobalt, and tin-copper. Moreover, it can be particularly preferably used for rust prevention treatment of noble metals such as gold, silver and palladium.

  The coating surface pretreatment of the metal surface using the metal coating ground treatment solution of the present invention can be carried out in the same manner as in the conventional method except that the metal coating ground treatment solution of the present invention is used.

FIG. 1 is a flowchart for explaining a coating method using the composition of the present invention.
In the start step a0, an article to be processed is prepared in which at least a part or the whole of the surface is made of one or more metals selected from copper, copper alloy, tin, tin alloy, chromium and noble metals. The Specific examples of the processed products, for example, like one or more of the various components comprised of the metal, an article plated in the component, article plated in the molding of synthetic resin It is done.

A degreasing process, a pickling process, etc. are given to a to-be-processed product as needed.
Degreasing can be performed according to a known method. For example, it is performed by supplying an alkaline aqueous solution to the surface of the article to be processed. The supply of the alkaline aqueous solution is performed, for example, by spraying the alkaline aqueous solution onto the article to be treated or immersing the article to be treated in the alkaline aqueous solution. As the alkali, those commonly used for metal degreasing can be used, and examples include alkali metal phosphates such as sodium phosphate and potassium phosphate. The alkali concentration in the aqueous alkali solution is appropriately determined according to, for example, the type of metal to be treated and the degree of contamination of the metal to be treated. Furthermore, the alkaline aqueous solution may contain an appropriate amount of a surfactant such as an anionic surfactant and a nonionic surfactant. Degreasing is performed at a temperature of about 20 to 50 ° C. (liquid temperature of the alkaline aqueous solution) and is completed in about 1 to 5 minutes. After degreasing, the product to be treated is washed with water and subjected to the next pickling process. In addition, degreasing to be immersed in an acidic bath, bubbling immersion degreasing, electrolytic degreasing, and the like can be appropriately combined.

  Pickling can be performed according to a known method. For example, it is performed by supplying an acid aqueous solution to the surface of the article to be processed. The supply of the acid aqueous solution is performed by spraying the acid aqueous solution onto the article to be treated, immersing the article to be treated in the acid aqueous solution, and the like, similarly to the supply of the alkaline aqueous solution in the degreasing treatment. As the acid, those commonly used for metal pickling can be used, and examples thereof include sulfuric acid, nitric acid, and phosphoric acid. The acid concentration in the acid aqueous solution is appropriately determined according to, for example, the type of metal to be treated. The pickling is performed at a temperature of about 20 to 30 ° C. (liquid temperature of the acid aqueous solution) and is completed in about 15 to 60 seconds.

In addition to degreasing and pickling, scale removal may be performed.
In step a1, the surface of the article to be treated is treated with the ground coating solution for metal coating of the present invention. The treatment is performed, for example, by supplying the surface treatment solution for metal coating of the present invention to the surface of the article to be treated. The supply of the ground coating solution for metal coating of the present invention can be performed, for example, by immersing the product to be treated in the ground processing solution for metal coating of the present invention, spraying the ground coating solution of the present invention for metal coating, The present invention is carried out by applying a ground treatment solution for metal coating. The treatment time and the temperature of the ground treatment liquid for metal coating of the present invention at the time of treatment are not particularly limited and can be appropriately selected from a wide range depending on the type of metal to be treated and the composition of the ground treatment liquid for metal coating of the present invention. In general, the rust prevention treatment is performed at a temperature of about 15 to 35 ° C., preferably about 20 to 30 ° C. (liquid temperature of the ground coating solution for metal coating of the present invention), about 5 seconds to 1 minute, preferably It ends in about 10 to 30 seconds. By this treatment, a film having excellent corrosion resistance is formed on the metal portion on the surface of the article to be treated. After the rust prevention treatment, the article to be treated is washed with water and subjected to the next drying step.

  In step a2, the article to be processed is dried. The article to be processed is dried at a temperature of about 70 to 120 ° C.

  In step a3, electrodeposition coating is performed on the workpiece. The electrodeposition coating is carried out according to a known method, for example, by completely immersing the article to be processed in a current-carrying tank filled with the electrodeposition coating paint and energizing it. Known cationic and anionic electrodeposition paints can be used for electrodeposition coating, such as epoxy resins, alkyd resins, fluororesins, silicone resins, acrylic resins, acrylic amino resins, polycarboxylic acid resins. , Synthetic resins such as polyamino resin, melamine resin, polyester resin, polybutadiene resin, vinyl copolymer, colored pigments such as titanium dioxide, carbon black, bengara, extender pigments such as kaolin, clay, talc, pigment dispersant, interface Examples thereof include electrodeposition paints containing an activator, an antioxidant, an ultraviolet absorber and the like. There are no particular restrictions on the electrodeposition coating conditions, and there is a wide range depending on various conditions such as the type of metal to be treated, the type of paint for electrodeposition coating, the size and shape of the current-carrying tank, and the use of the resulting coated article In general, the bath temperature (electrodeposition paint temperature) is about 10 to 50 ° C., the applied voltage is about 10 to 250 V, and the voltage application time is about 1 to 10 minutes. The article to be treated that has been painted is taken out of the energization tank, washed with water, and subjected to the next drying step.

  In step a4, the article to be treated that has been painted and washed with water is dried. The drying conditions are not particularly limited and can be appropriately selected from a wide range. Usually, the drying is performed at a temperature of about 50 to 130 ° C. and is completed in about 10 to 30 minutes.

  In step a5, the coating film formed on the surface of the product to be processed is baked and cured to be fixed on the surface of the product to be processed. Baking is performed while appropriately selecting the temperature and time according to the type of metal constituting the article to be treated, the composition of the coating film formed on the surface of the article to be treated, etc., but usually about 120 to 260 ° C., Preferably, the reaction is carried out at a temperature of about 150 to 250 ° C. and is completed in about 10 minutes to 1 hour.

Subsequently, it progresses to the end of step a6 and the article | item by which the coating film was formed on the metal surface is obtained .

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
Example 1
Each component was used in the ratio (% by weight) shown in Table 1, and the phosphate, oxidizing agent and nonionic surfactant were dissolved in water to prepare the composition of the present invention.
Aqueous ammonia (28% by weight) was used for pH adjustment.

(Example 2)
A steel plate having dimensions of 100 × 70 × 0.3 mm was treated with a plating bath described in Table 2 below to prepare a sample plate.

  The obtained plated sample plate was immersed in 1 liter of the composition of the present invention obtained in Example 1 for 30 seconds at room temperature, and then the plated sample plate was taken out of the composition of the present invention, washed with water, and washed at 70 ° C. for 20 minutes. The plate was dried for a minute, and the plated sample plate was pretreated with the composition of the present invention.

  An acrylic anion electrodeposition paint (trade name: Elecoat AM-1, manufactured by Shimizu Corporation, hereinafter abbreviated as “AM”) or an acrylic cationic electrodeposition paint (trade name: Elecoat CM, ( SHIMIZU Co., Ltd., hereinafter abbreviated as “CM”), electrodeposition coating under the conditions of a liquid temperature of 30 ° C., a coating time of 2 minutes, energization method: full immersion current, voltage of 60 V, and paint stirring: 1 cycle / hour Then, the sample plate was taken out, washed with water, and baked at 180 ° C. for 30 minutes to prepare a coated sample plate.

(Comparative Examples 1-2)
For comparison, a plated sample plate not subjected to pretreatment with the composition of the present invention (Comparative Example 1) and a commercially available chromate pretreatment solution instead of the composition of the present invention (trade name: Elecoat Connector, manufactured by Shimizu Corporation) For the plated sample plate (Comparative Example 2) pretreated using, electrodeposition coating was performed in the same manner as in Example 2 to prepare a coated sample plate.

(Test Example 1)
For the coated sample plates obtained in Example 2 and Comparative Examples 1 and 2, immediately after coating, after immersion in boiling water for 1 hour, and an aqueous solution for CAS (CASS) test (50 g of sodium chloride and 0.26 g of cupric chloride in water) Dissolve in water to make a total of 1 liter, add glacial acetic acid to this aqueous solution to adjust the pH to 3.2 ± 0.1, soak for 24 hours in a liquid temperature of 50 ° C., and then paint adhesion test according to JIS K5400 ( A cross-cut test was carried out, and the case where the coating film was peeled off was evaluated as x, and the case where it was not peeled off was evaluated as ◯. The results are shown in Table 3.

  From Table 3, it is clear that the various metals pretreated with the composition of the present invention have the same coating adhesion as the various metals pretreated with the chromate solution.

It is a flowchart explaining the metal coating method using the ground-treatment liquid for metal coating of this invention.

Claims (6)

(A) and one or more phosphate phosphate, ammonium salts of pyrophosphoric acid and polyphosphoric acid, sodium salt is selected from potassium and calcium salts,
(B) From one or more of hydrogen peroxide, persulfate, nitrate and permanganate, and one or more of oxyacid salts, oxides and sulfates of manganese, cerium, vanadium and tin and the oxidizing agent is selected,
(C) and a non-ionic surfactant, remainder Ri Ah with water, copper, copper alloy, tin, tin alloy, metallic paint surface treatment, characterized in that used for the painting surface treatment of chromium or precious metal liquid.   2. A phosphate comprising 0.1 to 15% by weight, oxidizing agent 0.01 to 5% by weight and nonionic surfactant 0.005 to 1% by weight, the balance being water. The surface treatment liquid for metal coating as described.   The ground treatment liquid for metal coating according to claim 1 or 2, wherein the pH is 8-11. Nonionic surfactants, metal paint undercoating liquid according to any one of claims 1 to 3, characterized in that the fatty alcohol nonionic surfactant. After processing the surface of the metal which is copper, a copper alloy, tin, a tin alloy, chromium, or a noble metal using the ground-treatment liquid for metal coating in any one of Claims 1-4, the metal surface is painted. A painting method characterized by 6. The coating method according to claim 5, wherein the metal surface is coated by an electrodeposition coating method.

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