JPS5836061B2 - Dou Oyobi Dokeigokinno Fushiyokuyokuyokuseihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for corrosion inhibiting treatment of copper and copper-based alloys.

Recently, penzotriazole (hereinafter abbreviated as BTA) has been used as a corrosion inhibitor for inhibiting corrosion of copper and copper-based alloys.
is often used, and this is a well-known fact, its anti-corrosion mechanism and effects have been introduced in numerous documents, and it is widely used for copper-based metal products.

BTA, chemical name 1,2,3-penzotriazole, is a white needle-like crystal substance with a molecular weight of 119.12, and a melting point of 95-95.
It exhibits a temperature of 99°C, has a weak vapor pressure as shown in Table 1, and is soluble in water, alcohol, and organic solvents.

Table 1 Temperature 'C 30 70 100 110 1
20 130 140 Vapor pressure mm/HP O. 04
0.07 0.1 0.16 0.32 0.58
0.97 The conventional method of applying BTA is 0.0 of BTA.
Using a solvent containing 5 to 0.5%, the BTA solution is applied by dipping, spraying, wiping, etc. depending on the object to form a corrosion-resistant film.

The solvent used for this is also selected depending on the target object, and other organic solvents such as water, alcohols, chlorinated hydrocarbons, glycols, ketones, and hydrocarbons are used.

In addition, when forming a film with particularly good corrosion resistance, 1 to 1
Heat treatment may be performed at 60 to 80°C in a 0% aqueous solution.

Or BTA0.0 1-5 V/rr? Copper-based metal products are also packaged in treated paper impregnated with BTA to suppress corrosion in the atmosphere created by BTA vapor inside the package.

However, in this case, it appears that it takes a considerable amount of time to form an inhibiting film on the metal surface, and during the normal packaging period, copper products are subject to corrosion when removed from the packaging and exposed to the atmosphere.

The method of the present invention relies on the vapor pressure of BTA;
A corrosion-inhibiting film is formed on the surface of copper and copper-based alloys in a gas phase in which TA and an alcohol represented by the general formula R-OHI: R represents a chain hydrocarbon moiety having 1 to 3 carbon atoms coexist. It is something.

The film formed by the method of the present invention has corrosion resistance that is no different from that of a film formed by applying a BTA solution.

The method of applying BTA requires labor and time to diffuse and dry the solvent, and depending on the solvent used, it can contaminate the air in the factory and its toxicity can pose health problems for workers. It may happen.

Furthermore, when carrying out corrosion suppression treatment on the inside of a long bent pipe, it is difficult to completely discharge the solvent to the outside after the treatment.
Therefore, undischarged solvent remains in the tube indefinitely, which is undesirable.

In the gas phase treatment method of the present invention, the treatment is carried out in a relatively dilute gas phase of BTA and alcohol in a single hour, so there is no need for subsequent drying, and there is no problem of the solvent remaining in the tube.

That is, alcohol (for example, methanol, ethanol, isopropanol) in a weight ratio of 5 to 15 is added to the BTA crystal and heated until it becomes liquid.

At this time, the appropriate amount of alcohol is such that the temperature is 70 to 80°C.

BTA having such a composition is placed in the lower part of a rectangular airtight container with a lid that can be opened and closed and can be heated, and a copper-based metal product is placed in the upper part so that the vaporized BTA gas can come into uniform contact with the container. When the temperature of the lower BTA is increased beyond the point at which the BTA exhibits a uniform liquid state, the vaporization of the BTA and alcohol is accelerated.

If air flows in from the outside in this state, the air flow first contacts the interface of the BTA melt, passes through the upper processing chamber, and is discharged to the outside from the exhaust port provided in the lid.
The vaporized gas of A and alcohol quickly forms a corrosion-inhibiting film on the surface of copper-based metal products.

The heating temperature at this time is 90℃±5℃, and the processing time is 3~
The flow rate of air for 15 minutes is controlled by the volume of the processing chamber and the shape of the object, but is suitably 0.5 to 101/min7't.

As the alcohol, methanol, ethanol, and isopropanol are used.

Note that water, chlorinated hydrocarbons, etc. can also be used as solvents other than alcohols, but the effect of BTA as a carrier is inferior to that of alcohol.

When BTA alone is treated in a similar manner, the amount of vaporization is small unless the temperature is raised above the melting point, and even if BTA is adsorbed by sublimation at a high temperature, it will not form a film, and of course it will not be corrosion resistant. There is no.

The test pieces treated by the above method were exposed to an atmosphere of SO2 gas and 50% exposure to evaluate the corrosion resistance of untreated and B
As a result of comparison with a test piece coated with a TA solution, the corrosion resistance was the same as that of a test piece coated with a BTA solution.

Examples will be described below. Note IPA (Inglovir Alcohol) L/) M e O H (Methanol) EtO
H (ethanol) chloro7ane (1,1,1-trichloroethane) corrosion test SO2 gas atmosphere, concentration 50PF time 4 hours Results display ◎ Complete, 01 part corrosion, △ Effective, × No effect.

Claims (1)

[Claims] 1 85-95% by weight of penzotriazole and 15-5%
A container containing a mixture with a carrier alcohol represented by the weight-related general formula R-OH [R represents a chain hydrocarbon moiety having 1 to 3 carbon atoms] is heated to 90 ± 5 ° C. to vaporize it, A corrosion-inhibiting film is formed on the surface of copper and copper-based alloys in a gas phase in which penzotriazole and carrier alcohol coexist, which are produced by introducing air into the container and accelerating its vaporization. Corrosion suppression method for atmospheric corrosion of copper and copper-based alloys.