JPS6144953B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to rust prevention treatment of steel materials such as hot-rolled pickled steel plates, cold-rolled steel plates, and cast iron. Generally, the surface of cold-rolled steel sheets and the like is subjected to surface treatment to prevent corrosion and maintain aesthetic appearance. In other words, since these various steel plates and the like take a considerable period of time after being manufactured before being processed and used according to their respective uses, they are coated with anti-rust oil or chemically treated, or packed with volatile anti-rust paper. Rust prevention management is carried out. However, all of these conventional rust prevention methods have the following drawbacks. When anti-rust oil is applied, not only does the oil cause stickiness, but the biggest drawback is that a degreasing process is required when the steel material is used, and the degreasing liquid must be disposed of as waste. Furthermore, if welding is performed with the rust preventive oil applied, there are problems such as the electrode becoming dirty and smoke being produced which is not favorable for the working environment. Already known water-soluble rust preventives, such as sodium nitrite, sodium borate, aromatic carboxylic acids, imidazoles, amines, and surfactants, are used alone or in combination, but they are mainly used in water. Although it has a rust-preventing effect in the atmosphere, it is inferior in rust-preventing ability when steel plates come into contact with each other in a humid atmosphere or with water attached. There are also rust preventives that contain higher aliphatic amines, higher fatty acids, etc., but these have drawbacks such as poor drying properties and the need for a removal process similar to rust preventive oils. . The present inventors have already revealed in Japanese Patent Publication No. 55-27694 that 1-hydroxybenzitriazole has an excellent antirust effect on steel materials. However, in this case, although the steel plate to be treated has excellent rust prevention properties after being dried with hot air, water is dropped onto the steel plate to be treated, the steel plate to be treated is placed on top of it, and the steel plate is left in a high temperature and humid atmosphere. As a result, it was discovered that in some cases, there was a weakness that caused discoloration and stains. The present invention solves the problems of the conventional methods and makes it possible to exhibit extremely good rust prevention effects without requiring any treatment in the next step. On the other hand, regarding mononitrobenzoic acid and nitrophthalic acid, for example, JP-A No. 48-95324 and JP-A No. 49-Sho.
2737, etc., and JP-A No. 51-6144, JP-A No. 51-6829, JP-A-Sho 51- regarding mixed compositions containing nitrophthalic acid and sodium nitrite with other additives
6830, etc., but these applications are only expected to have a rust-preventing effect when the steel is immersed in water, or only in the atmosphere. The effect of the present invention is not the rust prevention effect under a specific environment, but also in water, in the atmosphere, in an acid atmosphere, in a hot and humid atmosphere where water droplets are present while the steel plates to be treated are in contact with each other, or Excellent anti-rust effect on metal under various environments, such as when temper rolling fluid splashes onto the steel plate after rolling during the high-speed temper rolling process, or where steam from the rolling fluid adheres as water droplets. It is. The present invention is based on the general formula () (In the formula (), X and Y represent a hydrogen atom, a hydroxyl group, an alkyl group, a carboxyl group, a nitro group, or a sulfone group).

[Formula] or

[Formula] (In the formula (), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a carboxyl group, a nitro group, or a sulfone group) of nitrobenzoic acid, dinitrobenzoic acid, nitrophthalic acid, or aminobenzoic acid A mixed aqueous solution containing one or more of these at the same time is neutralized with aqueous ammonia, hydrazine, and amines (monoethanolamine, triethanolamine, aminoethylethanolamine, diethylethanolamine, etc.) to a pH range of 7 to 10. It is used for steel materials as an aqueous solution. A water-soluble polymer compound or a surfactant can also be added thereto. Furthermore, the objective can also be achieved by applying an emulsion of these mixed aqueous solutions, that is, a solution prepared by adding a water mixture of cutting oil, grinding oil, and rolling oil to the surface of the steel material to form a rust-preventing film. The above general formula () contained in the solution in this case
The concentration of 1-hydroxybenzotriazole and its derivatives is in the range of 0.01 to 10% (the same below weight%), and the nitrobenzoic acid of the general formula (), dinitrobenzoic acid, nitrophthalic acid, or aminobenzoic acid added thereto is One type or a mixture of two or more types of additives such as acids are all 0.01 to 5%.
However, in terms of rust prevention and economic efficiency, it is particularly preferable that the main components and additives are both in the range of 0.1 to 2%. When adding further surfactant, 0.001~
A range of 0.5% is preferable from the viewpoint of corrosion resistance or uniformity of the treated film, and contributes to improved rust prevention. Another feature of the present invention is that it is possible to directly paint or plate the surface of the treated steel material, and to obtain the same performance as when painting or plating an untreated metal surface. Example 1 1-Hydroxybenzotriazole 0.4%
- Add monoethanolamine as a neutralizing agent to an aqueous solution of nitrobenzoic acid 0.3% to adjust the pH to 8 as the treatment liquid, perform normal temper rolling,
Water was intentionally applied to a portion of the steel plate on the exit side of the roll, and the steel plate was shaped into a coil. Example 2 Monoethanolamine was added as a neutralizing agent to an aqueous solution of 0.4% 1-hydroxybenzotriazole, 0.2% 2,4-dinitrobenzoic acid, and 0.03% nonionic surfactant (polyoxyethylene alkyl ether), and the pH was adjusted to 9. The treated liquid is continuously sprayed onto a surface-cleaned cold-rolled steel plate and immediately dried using a rubber roll and a squeezing dryer. Example 3 3 to 1-hydroxybenzotriazole 0.4%
- The treatment solution is a 0.3% nitrophthalic acid aqueous solution adjusted to pH 8 by adding triethanolamine as a neutralizing agent, and the solution is continuously sprayed onto a surface-cleaned cold-rolled steel plate and immediately squeezed with a rubber roll and dried with a dryer. . Example 4 1-Hydroxybenzotriazole 0.5%
-Aminobenzoic acid 0.2%, 0-nitrobenzoic acid 0.2
% and a nonionic surfactant (polyoxyethylene alkyl ether) 0.03%, monoethanolamine was added as a neutralizing agent to adjust the pH to 8, and this was used as the treatment solution, and was continuously applied to a surface-cleaned cold-rolled steel sheet. Spray on the target and immediately squeeze with a rubber roll and dry with a hair dryer. Example 5 An aqueous solution containing 0.5% of 1-hydrobenzotriazole, 0.2% of 0-aminobenzoic acid, and 0.2% of 4-nitrophthalic acid was adjusted to pH 8 by adding aminoethylethanolamine as a neutralizing agent and used as a treatment liquid. Continuously spray on a surface-cleaned cold-rolled steel plate and immediately squeeze with a rubber roll and dry in a dryer. Example 6 1-Hydroxybenzotriazole 0.4%, 4-nitrophthalic acid in mineral oil emulsion water mixture
A treatment solution containing 0.2% and adjusted to pH 8 with triethanolamine was continuously sprayed onto a surface-cleaned cold-rolled steel plate, immediately squeezed with a rubber roll, and the water was removed with a dryer. Table 1 shows the rust resistance test results of the steel sheets treated by the method of the present invention and the comparative example, and Table 2 shows the results of direct paintability.

【table】

[Table] In the table, *: Humid box (50℃, 0.8%Rh) storage test 7 days, 10 days
Ten x 10 cm test pieces were tightened in a small vise and used for the test. **: The treatment solution concentration in each comparative example was 1%, and the treatment was performed in the same manner as in the case of the present invention. Commercial product A: Sodium nitrite system (1): The treated aqueous solution was dropped onto a treated steel plate, and the treated steel plates were stacked on top of each other, and a test was conducted to evaluate discoloration or rusting at the dripping area. (2): Tap water was dripped onto the treated steel plate, and the treated steel plates were stacked on top of each other, and a test was conducted to evaluate the rusting state under the water drop. (3): Put 0.6NHCl aqueous solution in the bottom of the desiccator,
A treated steel plate was placed on the perforated plate, the lid was closed, and the rusting status was evaluated after 24 hours. Evaluation: ◎...No change, 〇...Slight discoloration, △...Rust observed, ×...Approx. 10% rust, ××...Approx. 30% rust, ×××...60 Rust of more than %,

[Table] In the table, *1: Paint...acrylic and epoxy urea *2: Sodium nitrite (1): Crosscut Erichsen 7mm, Goban 2mm
Square evaluation method: The coating film was peeled off with a cellophane tape, and the degree of peeling was evaluated. (2): Place the primary adhesion test sample in deionized water at 40°C.
Immediately after immersion for 24 hours, the adhesion of the coating was tested. The test items are the same as the primary adhesion test. Evaluation: 10 (excellent) to 0 (unsatisfactory) As described above, according to the method of the present invention, not only is the rust prevention effect sufficiently exhibited in various environmental atmospheres, but also the removal of the rust preventive agent is completely eliminated prior to the next process. Since painting and other necessary treatments can be carried out immediately without the need for such treatment, work efficiency can be improved. In addition, in the case of conventional treatments containing sodium nitrite, the toxicity of the treatment has recently become a problem, but in the case of the present invention, such toxicity is extremely low, and it can also be used during processing such as welding. This method is far more effective than conventional surface treatment methods, as it does not pollute the environment due to smoke or impair work efficiency due to electrode contamination.

Claims (1)

[Claims] 1 General formula () (In the formula (), X and Y represent a hydrogen atom, a hydroxyl group, an alkyl group, a carboxyl group, a nitro group, or a sulfone group). Nitrobenzoic acid, dinitrobenzoic acid, nitrophthalic acid, or aminobenzoic acid represented by the following formula: acid 1
1. A method for rust-preventing steel materials, which comprises treating steel materials with an aqueous solution or emulsion solution having a pH of 7 to 10 by adding one or more seeds.