JPH0518909B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a volatile rust preventive agent for protecting various metals such as iron, iron alloys, copper, and copper alloys. [Prior technology] Metal corrosion inhibitors that vaporize at room temperature are called volatile rust inhibitors (VCI), and vaporized gases chemically and physically adsorb and react with the metal surface to form a thin film. The film blocks water and oxygen and prevents rust. Traditionally, such VCI has been used as a powder, or as a vaporizable anticorrosion paper or film coated or impregnated on paper or plastic film.
It is also used as a volatile rust preventive oil added to oil, which is effective in preventing rust. Dicyclohexylammonium nitrite (DICHAN) and diisopropylammonium nitrite (DIPAN), which are commonly used as VCI, are effective against iron and iron alloys, but are less effective against non-ferrous metals, such as copper and copper. Benzotriazoles, which are very effective on alloys, are less effective on other metals. Additionally, there are reports that prazoles are effective against zinc, but none of them is effective against all metals individually, and their uses are differentiated depending on the type of metal. However, in reality, iron and iron alloys and nonferrous metals such as copper and copper alloys often coexist, and it is desired to develop a VCI that is effective for both iron and nonferrous metals. [Problem to be solved by the invention] It is possible to mix DICHAN or DIPAN, which is highly effective against ferrous metals, with benzotriazole, which is highly effective against copper-based metals, and make this a VCI that can be used for both ferrous and non-ferrous metals. Although this is considered common sense, in reality it is not done as mentioned above. In order to clarify this question
When one type of DICHAN or DIPAN and one type of benzotriazole or methylbenzotriazole were combined and mixed,
The melting points of DICHAN, DIPAN, benzotriazole and methylbenzotriazole are respectively
Although the temperatures were 176°C, 129-130°C, 98-99°C and 80-85°C, all mixtures partially melted and became sticky even at room temperature (20-25°C). . VCI is used as a powder, or if used as a powder, it may impair workability or aesthetics, or if there is a possibility that it may enter the human body, it may be used as a desiccant in cloth, non-woven fabric, or paper bags. Although it is often used as a vaporizable rust-preventing paper, it cannot be put to practical use in a sticky state, which is why it is presumed to have reached its current state. In view of the current situation, the present inventors conducted studies to develop a practical VCI for both ferrous and non-ferrous metals, and found that one or two of DICHAN or DIPAN and one of benzotriazole or methylbenzotriazole were used. When one or two types are attached to calcium silicate, there is no stickiness in appearance, and what is even more surprising is that the anti-corrosion effect is synergistically improved significantly compared to the anti-corrosion effect of each individual product on each target metal. The present invention was completed based on the discovery that the present invention can be achieved. [Means for Solving the Problems] According to the present invention, calcium silicate is impregnated with at least one of dicyclohexylammonium nitrite and diisopropylammonium nitrite and at least one of benzotriazole and methylbenzotriazole. A volatile rust preventive agent is provided. The volatile rust preventive agent of the present invention can be produced, for example, as follows. That is, one or two of DICHAN or DIPAN and one of benzotriazole or methylbenzotriazole
The seed or two are dissolved in a solvent such as water, methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, propylene glycol, etc., and powdered or granular calcium silicate is mixed into this solution and stirred. Next, the solvent is distilled off from the mixture to obtain the desired product. The solvent is
From the viewpoint of solubility, cost, and boiling point, methyl alcohol is preferred, but is not limited thereto, including those other than those mentioned above. Various forms of calcium silicate have been investigated, including powder, granules, and disk-like shapes (tablets), but disk-like forms are relatively disadvantageous in terms of adhesion due to surface area. When it is desired to obtain the VCI of the present invention in the form of a tablet, the powdered VCI obtained by the above method may be molded by a known method, or the combination of the above components and calcium silicate may be directly mixed with a known method. It can be molded using this method. Further, the VCI of the present invention may be used in combination with other known rust inhibitors, such as dicyclohexyl ammonium caprylate, cyclohexyl amine carbonate, cyclohexyl ammonium laurate, nitronaphthalammonium nitrite, and pyrazoles, as necessary. You can also. The volatile rust preventive agent of the present invention has a versatile and excellent rust preventive effect, as is clear from the following examples. [Example] Hereinafter, the present invention will be further explained with reference to Examples. Example 1 Using 150 ml of methyl alcohol as a solvent, 25 g of DICHAN or 25 g of DIPAN and 25 g of benzotriazole were dissolved therein. 50 g of powdered calcium silicate was mixed, stirred, and then heated and distilled under reduced pressure using an evaporator to remove methyl alcohol. VCI with no sticky appearance
was gotten. Example 2 Except for using a granular product as calcium silicate,
The treatment was carried out in the same manner as in Example 1. A VCI with no sticky appearance was obtained. A rust prevention test was conducted on the VCI obtained in these examples. The test method and results are shown below. 1 Properties of calcium silicate Powder Granular 2 Type of rust preventive agent BT-120 (1,2,3-Benzotriazole) DICHAN (Dicyclohexylammonium
nitrite) DIPAN (Diisopropylammonium nitrite) 3 Type of test piece 1. Copper...JIS test piece (C1100P) 2. Iron...JIS test piece (S, 15C) 4. Test method Wide mouth glass bottle (with cap) as shown in Figure 1 1. Water, Fe, Cu, and calcium silicate impregnated with a volatile rust preventive agent were placed in each small bottle 2 and allowed to stand. The bottles were placed in an incubator and kept at 50°C for 5 hours, then rapidly cooled to form water droplets. let Rapid cooling and heating are repeated, and the degree of rust on the test piece is observed over time. 5 Types of rust prevention test samples

【table】 6 Test results

【table】

[Table] ○‥No rust ◎‥No rust, surface gloss

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the apparatus used for the rust prevention test in Examples. 1...wide mouth glass bottle, 2...small bottle.

Claims (1)

[Claims] 1. A volatile rust preventive agent obtained by impregnating calcium silicate with at least one of dicyclohexylammonium nitrite and diisopropylammonium nitrite and at least one of benzotriazole and methylbenzotriazole.