JPS5835263B2 - Rust inhibitors and rust prevention methods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rust preventive agent and a rust preventive method for metal products built into wooden frames.

2. Description of the Related Art As a means for preventing rust of metal parts housed in wooden cases such as watches, televisions, stereos, etc., it is known to contain amines and alcohols in a paint and apply this paint to the inside of the wooden case.

This is because the amine and alcohol undergo an addition reaction, producing an amine-alcohol adduct, which reduces the evaporation rate of the amine, causing the amine to be retained in the paint for a long time and causing the acid gas released from the wood to It is neutralized as

Since the reaction between amines and alcohols is an addition reaction, it produces products in a wide range of molar ratios.

The amine-alcohol adduct in this state is called the crude product.

This crude product is purified, and the product that has the most stable composition ratio of amine and alcohol is called a purified product.

In the above-mentioned prior art, the amine-alcohol addition product is used in the form of a crude product.

The present invention provides a rust preventive agent obtained by purifying a reaction product of organic amines and alcohol.

Crude products are not inferior to refined products in terms of rust prevention ability.

However, when actually used as a rust preventive agent, purified products have the following advantages.

(a) The odor of unreacted amine and alcohol is eliminated.

(b) Refined products have a higher melting point and can be used as a solid over a wider temperature range.

(／→ The crystal shape is constant and there is little variation in quality.

(Y) Impurities in raw materials are removed, and the negative effects of impurities on metals other than iron are eliminated.

Among the amines used to produce amine-alcohol adducts, typical ones are listed below.

laurylamine, stearylamine, cyclohexalamine, dicyclohexylamine, jetanolamine,
Monoethanolamine, triethanolamine, diisopropylamine, triethylenetetramine, morpholine, dicyancyamidine, ammonium nitronaphthalate.

Representative alcohols that can be used are as follows.

Glycerin, ethylene glycol, propyl alcohol, benzyl alcohol, fropagyl alcohol, cyclohexanol, butanol, tetramethylene glycol, pentaerythritol, trimethyl carbinol, propylene glycol, hexanol.

The reaction formula between an amine and an alcohol is shown below as an example of reacting a primary amine with a monohydric alcohol to generate an amine/alcohol addition product.

In addition, an example of the reaction between a secondary amine and a dihydric alcohol is shown below. becomes.

In the above reaction formulas (1) to (3), the bonds shown by broken lines are hydrogen bonds, but it is thought that they actually form a complex bond system under the influence of nearby free molecules. .

Therefore, the chemical equivalence reaction is no longer 1:1, and purification is required to obtain a pure product.

Further, during the synthesis reaction of the crude product, some unreacted substances are present and are in an amorphous solid state, and the unreacted substances are occluded therein.

Examples of purification methods for amine-alcohol addition products include the following.

(1) Recrystallization method Alcohol-based solvents are inappropriate for the recrystallization method.

Recrystallization melt protectants that have shown good results using the recrystallization method include ketone compounds such as acetone and methyl ethyl ketone, aromatic compounds such as benzene and toluene, and hydrocarbons such as n-hebutane and cyclohexane.

These include ethers such as ethyl ether and methyl ethyl ether, and ester compounds such as ethyl acetate and methyl propionate.

These solvents are heated to near their boiling point to dissolve the amine-alcohol adduct to a level higher than its solubility at room temperature, and then slowly cooled to obtain purified crystals.

Note that it is also possible to directly dissolve amines and alcohols in a recrystallization solvent and react and crystallize them.

(2) Distillation method In order to prevent air oxidation of the amine, the amine-alcohol adduct is distilled under reduced pressure while passing nitrogen gas through it to obtain a purified product.

Most combinations of amine-alcohol adducts do not dissociate.

(3) Put the crude amine-alcohol adduct into the sublimation flask,
Heat the bottom of the flask to dissolve.

An inert gas such as nitrogen gas or helium gas is passed through the flask, and the upper part of the flask is cooled with water or air to cause the vaporized amine-alcohol adduct to crystallize on the inner wall.

Although the purification yield is lower than that of the recrystallization method using a solvent and the distillation method, the highest purity can be obtained.

(4) Other amine-alcohol adducts can also be packed in a glass tube and purified by the zone methylting method.

The purified amine-alcohol adduct obtained by the above purification method is in the form of a fine powder and can be directly sprayed on metal parts as a rust preventive agent, but it can also be used in the following ways: can.

(1) Solidification A refined product of a powdered amine-alcohol adduct is melted or pressurized to solidify it into a certain shape such as a pellet or block, and is used as a rust preventive agent.

If the amine/alcohol adduct is used as a rust preventive agent in powder form, it will easily evaporate due to its large surface area and the rust prevention period will be short.
Spraying it as a powder onto parts to be rust-prevented, such as ferrous parts, may directly come into contact with non-ferrous parts and have an adverse effect.Also, it is inconvenient to handle as a powder, and it is difficult to check the quantity. There was a drawback.

By solidifying the powder, the surface area becomes smaller and long-term rust prevention is possible, direct contact with the parts to be rust-prevented is reduced, handling is easy, and the number of molded rust preventive agents can be controlled. There are advantages such as the ability to visually see the vaporization loss.

(2) Bagging.

The purified amine-alcohol adduct is placed in a breathable bag as a powder and used as a rust preventive agent.

As the material for the bag, appropriate materials such as paper, cloth, plastic laminated paper, and plastic film can be used.

Packing in bags prevents the rust preventive agent from coming into direct contact with the parts to be rust-prevented, allowing markings to be made on the bag, controlling vaporization power, and enabling long-term rust prevention.

Another advantage is that workers do not come into direct contact with the rust preventive agent, and rust prevention can be controlled by the number of bags.

Note that the purified product may be solidified and sealed in a bag.

(3) Dissolved in oil.

It is used by mixing purified amine/alcohol products with oil.

Amine-alcohol addition products have good solubility in oil and do not reduce the lubricity of oil.

As the oil used, appropriate oils such as kerosene, spindle oil, turbine oil, grease, silicone oil, synthetic oil, etc. are used.

The proportion mixed into the oil ranges from 0.01 weight percent to 70 weight percent depending on the purpose of use.

Oil mixed with rust preventive agents is used in machines, motor bearings, etc., depending on the purpose.

By mixing the amine-alcohol adduct refining valve with oil in this way, there are advantages such as no influence on non-ferrous metals and no oil stain.

Next, some embodiments of the present invention will be described.

The resulting amine/alcohol adduct was dissolved in heated acetone until saturated, and the solution was cooled with ice water to obtain cyclohexylamine/ethylene glycol crystals.

Those that are not recrystallized have a strong amine odor, but the amine odor disappears on the recrystallized surface, and the melting point is mixed, and Example 1 is mixed with rhohexane.
When recrystallized in the same manner as above, the raw material disappeared and a rust preventive with few impurities was obtained.

The mixture was mixed and reacted, transferred to a flask, heated to vaporize, and crystallized in a cooling section and collected. Colorless and odorless needle-shaped crystals were obtained.

The raw material had a strong amine odor and was unsuitable for rust prevention in areas where people would be close to it, but its purification made it easier to handle.

The reaction product was purified by vacuum distillation while passing nitrogen gas.

Although the rust prevention effect was comparable to that of the crude product, crystals containing no impurities were obtained.

The amine-alcohol adduct produced by mixing was recrystallized with ethyl ether solvent, and the resulting high-purity crystals were catalyzed and pelletized using a molding machine.

When these pellets were sealed in a breathable paper bag and used as a rust preventive agent in a parts box, the odor was extremely low compared to crude products, and at the same time, since low-molecular amines were removed, there was no effect on discoloration of brass etc. lost.

were mixed, zinc powder was added, nitrogen gas was passed through the mixture, and the mixture was purified by vacuum distillation of IQmm) (g).

When the crude product is added to lubricating oil, it accelerates the deterioration of the lubricating oil due to free amines, but the rust-preventing lubricating oil to which the purified product was added became extremely stable.

Claims (1)

[Claims] 1. A rust preventive agent obtained by purifying a reaction product of organic amines and alcohol. 2. A rust preventive agent made by refining the reaction product of organic amines and alcohol and solidifying it. 3. A rust preventive agent made by purifying the reaction product of organic amines and alcohol and placing it in a breathable bag. 4. A rust preventive agent characterized in that a rust preventive agent obtained by refining a reaction product of organic amines and alcohol is used by mixing it with oil.