JPS6147910B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rust preventive agent, and more particularly to a rust preventive agent in which a rust preventive substance is added to a sublimable composition. Conventionally, volatile rust preventive agents are mainly crystalline powders such as benzoates and nitrites of various amines used as they are or as rust preventive paper impregnated with paper. Since these salts generally have low vapor pressure, they have the disadvantage that the metal rusts to some extent before a protective film is formed on the metal surface. As a result of repeated research to develop an excellent rust preventive agent that eliminates the above drawbacks, the present inventors were able to control the volatilization of a substance that has rust preventive ability.
The present inventors have discovered a sublimable carrier that is tasteless, odorless, nontoxic, and has low hygroscopicity, and have completed the present invention. That is, the present invention provides a sublimable rust preventive agent, which is obtained by adding a rust preventive substance to a sublimable composition comprising a sublimable hydrocarbon and a sublimable or volatile polar compound. The sublimable hydrocarbons used in the present invention include adamantane, endo-trimethylenenorbornane (hereinafter abbreviated as TMN), cyclododecane (hereinafter abbreviated as CD), trimethylnorbornane,
There are various compounds such as norbornane. Adamantane is a non-toxic, odorless, sublimable hydrocarbon that is insoluble in water, and has a high melting point (268°C), so even when two or more types of crystalline hydrocarbons are mixed together, the melting point does not drop sharply. Therefore, it can be easily mixed and molded with other sublimable hydrocarbons. In addition, it has good shape retention after molding, and when mixed with other sublimable hydrocarbons, the mechanical strength of the molded product can be increased.
However, adamantane has drawbacks such as a low ability to retain liquid substances and, when used alone, causes powder to form on the surface of the carrier, reducing commercial appeal. Sublimable hydrocarbons other than adamantane alone can usually contain less than 2% by weight of rust preventive substances, and their retention is insufficient. It is preferable to select the sublimable hydrocarbon based on the rust prevention period, that is, the required sublimation rate of the carrier, and determine the amount of the sublimable hydrocarbon to be blended in the composition. For example, when using adamantane and TMN together,
TMN from 99% to 1% to 25% by weight of adamantane
Blend at a ratio of 75% by weight. If TMN is less than 75% by weight, powder of adalanthan, which has a lower sublimation rate than TMN (1/8 of the sublimation rate of TMN), will be scattered on the surface of the composition, which is not preferable because the commercial value will decrease. When adamantane and CD are used together, adamantane and CD can be mixed in any ratio. The reason is that the sublimation speed of CD is slower than that of adamantane (1/2 of the sublimation speed of adamantane)
Therefore, CD remains on the surface of the composition, but CD is a three-dimensionally continuous homogeneous phase with a low melting point (60°C) and does not form powder. Usually 95% to 95% CD to 5% to 95% by weight of adamantane
It is preferable to mix it in a proportion of 5% by weight. As the polar compound having sublimability or volatility, a substance that is almost incompatible with sublimable hydrocarbons such as adamantane at room temperature is used. For example 2.2
-dimethyl-1,3-propanediol, 1,4
- Crystalline alcohols such as cyclohexanediol and 1,6-hexanediol, sublimable polar compounds such as dimethyl fumarate, ε-caprolactam, paradimethoxybenzene, benzoic acid, trioxymethylene, and coumarin, and diethyl fumarate;
These include volatile polar compounds such as ethylene glycol derivatives. These may be used alone or in combination. The polar compound is appropriately selected depending on the properties of the antirust substance used. For example, when using a rust preventive substance having an amino group, it is generally preferable to select a polar compound having a hydroxyl group or the like that has the ability to form a hydrogen bond with the rust preventive substance. It is appropriate that the amount of the polar compound to be blended is changed depending on the properties of the sublimable hydrocarbon, antirust substance, and polar compound used. When using ε-caprolactam, 0.1 to 5% by weight based on TMN;
For an adamantane-TMN composition consisting of 1-25% by weight of adamantane and 99-75% by weight of TMN, the amount is 0.1-10% by weight based on CD.
10% by weight, and 0.5 to 20% by weight for adamantane-CD compositions. Benzoic acid, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanediol and 1.
When using 6-hexanediol, CD
and 0.1 to 10% by weight to the adamantane-CD composition. When trioxymethylene is used, it is used in a proportion of 0.1 to 20% by weight relative to TMN and 0.5 to 90% by weight relative to the adamantane-TMN composition. Polar compounds retain and contain anti-rust substances,
It reduces the distribution ratio of the rust preventive substance to the sublimable hydrocarbons that form a three-dimensional continuous phase, and prevents a drop in the melting point of the sublimable hydrocarbons. Therefore, the mechanical strength of the composition does not decrease due to the addition of anti-rust substances and the like.
If the polar compound is a substance that can maintain crystallinity even after containing the rust preventive substance, the mechanical strength of the composition will further increase. The antirust substances used in the present invention include volatile amines such as morpholine, diisopropylamine, dicyclohexylamine, diisobutylamine, and piperidine, volatile acetylene compounds such as propargyl alcohol, and 2-butyn-1-ol;
There are other volatile compounds with relatively high vapor pressure that have antirust properties. The proportion of the rust preventive substance to be added is not particularly limited and varies depending on the type of the rust preventive substance added and cannot be determined unambiguously, but generally it is 0.1 to 20% by weight of the rust preventive substance to the sublimation rust preventive agent. It is. Further, fragrances and other substances can be added as appropriate. The sublimable rust preventive agent of the present invention has a sublimable composition in which a polar compound exists discontinuously and innumerably as fine crystal grains or liquid particles in a nonpolar sublimable hydrocarbon, and the rust preventive substance is Because it is adsorbed or dissolved in the crystal grains or liquid particles of the polar compound,
Although the rust inhibitor cannot freely move and diffuse within the composition and the volatilization rate of the rust inhibitor is different from the sublimation rate of the sublimable composition itself, the rust inhibitor will sublimate with the sublimation composition of the carrier. Vaporize. Therefore, the amount of volatilization of the rust preventive substance remains at a constant value during the sublimation process, and a constant rust preventive power is maintained for a long period of time. To produce the rust preventive agent of the present invention, a sublimable hydrocarbon such as adamantane and a sublimable or volatile polar compound are blended, heated and melted, then a rust preventive substance is added, and the mixture is cooled and solidified. Alternatively, the desired rust preventive can be obtained by further crushing and compression molding. The rust preventive agent thus obtained has excellent mechanical strength and commercial appearance, and has an extremely wide range of applications because the rust preventive substance is supported by a sublimable composition with low hygroscopicity. Next, the present invention will be explained in detail with reference to examples. Example 1 20 parts by weight of adamantane, 80 parts by weight of TMN and 1.
After heating and melting 1 part by weight of 4-cyclohexanediol and uniformly mixing, 2 parts by weight of morpholine was added, and the mixture was poured into a shear dish with a diameter of 90 mm and a height of 15 mm to solidify to obtain a rust preventive agent. This was sublimated in an air stream at room temperature, and its sublimation characteristics were determined. The results are shown in Figure 1. The morpholine concentration in the figure indicates a relative concentration with the initial concentration of morpholine in the composition after molding being 1. It can be seen from FIG. 1 that the morpholine concentration remains constant despite a decrease in the weight of the entire rust inhibitor. Example 2 100 parts by weight of TMN, 2,2-dimethyl-1,3-
The same operation as in Example 1 was carried out using 1 part by weight of propanediol and 2 parts by weight of diisopropylamine. The results are shown in Figure 2. Example 3 Adamantane, TMN, 2.
2-dimethyl-1,3-propanediol, ε-
A rust preventive agent (diameter 20 mm
φ, thickness 10 mm, weight 2.3 g) was obtained. Using this rust preventive agent, a rust prevention test was conducted in accordance with "JIS Z0236-1974 (General test methods for rust preventive oils) 6.7 Volatile rust prevention properties". Similar tests were also conducted using tablets that had been sublimated for 2 or 3 days at room temperature in an air stream. The results are shown in Table 2.

【table】

【table】 [Brief explanation of the drawing]

FIGS. 1 and 2 are graphs showing the sublimation properties of the rust preventive of the present invention.

Claims (1)

[Claims] 1. A sublimable rust preventive agent obtained by adding a rust preventive substance to a sublimable composition comprising a sublimable hydrocarbon and a sublimable or volatile polar compound. 2. The sublimable rust inhibitor according to claim 1, wherein the sublimable hydrocarbon is one or more substances selected from adamantane, endo-trimethylenenorbornane, and cyclododecane. 3. The sublimable rust inhibitor according to claim 1, wherein the sublimable hydrocarbon is a combination of adamantane and endo-trimethylenenorbornane. 4 The polar compound having sublimation or volatility is 2,2-dimethyl-1,3-propanediol,
1,4-cyclohexanediol, 1,6-hexanediol, ε-caprolactam, paradimethoxybenzene, benzoic acid, trioxymethylene,
The sublimable rust preventive agent according to claim 1, which is one or more substances selected from coumarin, diethyl fumarate, and ethylene glycol derivatives. 5. Claim 1, wherein the rust preventive substance is one or more substances selected from morpholine, diisopropylamine, dicyclohexylamine, diisobutylamine, piperidine, propargyl alcohol, and 2-butyn-1-ol. Sublimation rust inhibitor as described.