JPS61143331A - Stabilization of solvent - Google Patents

Abstract

PURPOSE:To obtain a solvent having improved chemical stability, free from corrosivity to metallic materials such as copper, zinc, iron, etc., and most suitable as a cleaning agent, by adding a stabilizer selected from N- methylmorpholine, benzotiazole, nitromethane and nitroethane to a solvent. CONSTITUTION:1,2-Dichloro-1,1-difluoroethane (abbreviated as flon 1326) useful as a cleaning agent for various articles because of its inccombustibility, low toxicity, excellent solubility and moderate boiling point, is stabilized by the addition of one or more components selected from N-methylmorpholine, benzotriazole, nitromethane and nitroethane. Preferably, the amount of N- methylmorpholine, nitromethane or nitroethane is <=5 vol%, and that of benzotriazole is <=3,000 ppm (wt) based on the solvent.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for stabilizing 1,2-dichloro-1,1-Schiff A/oloethane (hereinafter referred to as Freon 162b). It is highly resistant to water, has low toxicity, and has excellent solubility and a moderate boiling point, so it can be used as a cleaning agent for a variety of items. For example, semiconductor materials such as silicone wafers and silicon chips, semiconductors such as IO and L8, printed wiring boards, relay switches, micro motors, etc., mechanical equipment, watches, cameras, micro bearings, lenses, etc. Degreasing cleaner Kl for precision instruments
It is for f.

(Prior Art) Freon 132b has not yet been practically used in industry, and there are many unknowns about its characteristics.

Among them, it exhibits a decomposition behavior different from conventional chlorine-based solvents and fluorine-based solvents that do not contain fluorine or hydrogen atoms.
A sufficient method for its stabilization is not yet known.

(Problems to be Solved by the Invention) Freon 132t) is more stable than chlorinated solvents such as methyl chloroform, tetrachloroethylene, and trichloroethylene, and stabilization is not necessarily required under general usage conditions. However, in cases where moisture coexists,
Electronic equipment and precision I! When the required quality level is high and strict, such as when cleaning equipment, stability may become a problem. In particular, it is frequently used in electronic/electrical equipment and precision equipment (・When deterioration of the solvent occurs in the presence of metal materials such as copper, zinc, and iron, it also causes corrosion of these metals. This will adversely affect the quality of the items being washed.

(Problem! Means for Solving) The present inventors have conducted various studies in an attempt to improve the stability of Freon 132b, and as a result, have found a method and arrived at the present invention.

That is, the present invention provides one or more stabilizers selected from Freon 132bKN-methylmorpholine, Pentritriol, nitromethane, and nitroethane. This is a method for stabilizing Freon 132b, which is characterized by addition. The amount of stabilizer added in the present invention is not particularly limited, but usually, for N-methylmorpholine, nitromethane, and nitroethane, it is less than 5 volumes per solvent, and for pens, doors, and doors, it is 3 volumes per solvent.
000 ppm by weight or less. If the amount added is larger than this, it is not a good idea because the liquid may become colored, become precipitated as insoluble matter, or become flammable. Furthermore, the method of the present invention can also be applied to mixed solvents containing Freon 132tl' as the main component, i.e., methanol, ethanol, inzolopanol, imbutanol, tart-butanol, acetone, as long as the solvent properties of Freon 162b are not significantly changed. , methyl ethiketone, ethyl acetate, methylene chloride r, etc. Keflon 132t) can also be applied to a mixed solvent containing a small amount of K. (Effects of the invention) Flon 132b stabilized by the present invention and its mixed solvent It has extremely high chemical stability and rarely corrodes metal materials such as copper, zinc, and iron, so it can be widely used as a cleaning field in various fields.

(Example) The present invention will be explained below using examples.

Incidentally, the stability tests and tests in the Examples were conducted by the following method. Stabilizers are indicated by the following abbreviations.

N-methylmorpholine: NMM Nitromethane: NM Nitroethane 2NB Ben ψ tria 1 unit: BTA Stability test @i: Sample 5Qm was placed in a glass bottle with a capacity of 100 d, and thoroughly polished zinc, steel, Place a metal test piece such as iron so that its lower half touches the liquid phase [
Seal and process at 60°C for 96 hours. Example 1 Corrosion state of metal piece: Observed separately in the part exposed to the gas phase and the part immersed in the liquid phase.
The various stabilizers shown in Table 1 were added to prepare T samples, and the stability mV was conducted using zinc as a metal test piece. Also, for comparison, Freon 1321 (without adding stabilizer)
A stability test was also conducted with K, and the results are shown in Table 7-1.

Example 2 The same test as in Example 1 was conducted except that copper was used as a metal test piece. The results are shown in Table-2.

Example 6 The same test as in Example 1 was conducted except that iron was used as the metal test piece. The results are shown in Table-3.

Example 4 11001 ppm of water and 5 volumes of ethanol yr
Add NMM as a stabilizer to a mixed solvent containing Freon 132b, and add 2 parts by volume to the mixed solvent, and 100 parts by weight as well as BTAy.
A stability test was conducted using iron, zinc, and copper 7 as metal test pieces, and a mixed solvent with no stabilizer added was used for comparison. Table 4 shows the results.
Shown below.

(Below! p!, white) Table-1 Table-2 Table-6 Table-4

Claims (1)

[Claims] 1,2-dichloro-1, characterized in that one or more selected from N-methylmorpholine, benzotriazole, nitromethane and nitroethane is added.
Method for stabilizing 1-difluoroethane.