JPS585170B2 - Stabilized methyl chloroform composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to stabilized methylchloroform compositions.

Methyl chloroform has a high ability to dissolve oil and grease, is nonflammable, and is trichloroform.

It has characteristics such as being less toxic than solvents such as ethylene and perchlorethylene, and is widely used as a solvent for degreasing and cleaning metals, treating fibers, and paints and adhesives.

However, methyl chloroform is relatively unstable and highly sensitive to metals, especially aluminium.

When nickel, zinc, and iron are present, they react with each other, directly extracting chlorine, and the decomposition progresses in a chain reaction, causing the liquid to become colored and eventually turn into a tar-like substance and black carbide.

Perchlorethylene, trichlorethylene, 1,1.2
-Different from trichloroethane, which preferentially causes oxidative decomposition and catalytic dehydrochlorination, methylchloroform is unique in that it preferentially causes this type of decomposition reaction.

Therefore, many unique stabilizing formulations have been proposed to suppress this decomposition reaction and stabilize methyl chloroform.

For example, cyclic ethers, alcohols, nitro compounds, nitriles, epoxides, etc. may be added singly or in combination.

However, the stabilizers proposed so far are still insufficient to stabilize methyl chloroform.

For example, even if it is stable against aluminum, it is not necessarily stable against zinc and iron, which are generally widely used as industrial materials. In such cases,
It reacts with these metals and often corrodes them.

The inventors of the present invention have improved these drawbacks and have conducted various studies on a methyl chloroform composition that is particularly stable against iron and zinc, and as a result, they have finally arrived at the present invention.

That is, the stabilized composition proposed in the present invention is a stabilized methyl chloroform composition characterized by containing an alkyl tin carboxylate.

The alkyl tin carboxylic acid salts used in the present invention include:
dialkyltin maleate, dialkyltin diacetate,
Dialkyltin dilaurate, dialkyltin distearate, trialkyltin acetate, trialkyltin laurate, trialkyl; tin stearate, monoalkyltin triacetate, monoalkyltin trilaurate, monoalkyltin tristearate, and the like.

Suitable alkyl groups are butyl, pentyl, and octyl groups.

Among these compounds, dialkyltin maleate, dialkyltin dilaurate, and dialkyltin distearate are preferred, and dibutyltin maleate is more preferred.

These compounds can be used alone or in combination of two or more.

The amount of these compounds to be used can vary widely depending on the intended use of the composition and conditions of use, but is usually at least 5 PPn by weight relative to methyl chloroform.

When the amount is less than this, the effect is generally not obvious, but when the composition of the present invention is used for degreasing and cleaning metals or dry cleaning, an amount of 1% by weight or less is usually sufficient.

However, when the composition is used as an adhesive or coating component, it can be dispersed in addition to solubility to obtain a high degree of stability, and its content may reach as much as 5% by weight.

It is also possible to prepare a composition containing these stabilizers at a high concentration and dilute it appropriately before use.

Furthermore, if necessary, it is possible to use a known stabilizer in addition to the stabilizer proposed in the present invention. For example, when trying to have all the comprehensive practical performance of methyl chloroform in metal degreasing and cleaning, etc. 1,4-dioxane, dioxolane, trioxane, methylbutynol, tert
-butanol, iε0-butanol, tert-amyl alcohol, nitromethane, nitroethane, nitropropane, 1,2-butylene oxide, glycidol, and the like.

The composition according to the invention is extremely stable, especially in the presence of moisture, and is highly stable against iron and zinc, and does not corrode these metals, making it suitable for all applications in which methylchloroform is normally used. It can also be used.

Examples include degreasing detergents for metals, dry cleaning agents or stain removers for clothing, solvents for aerosols, solvents for paints and adhesives, and solvents for extraction.

Hereinafter, the effects of the present invention will be specifically explained using Examples and Comparative Examples.

The amount of stabilizer added in the tables of Examples and Comparative Examples below is based on the weight of methyl chloroform.
The metal specimen and stability test method are as follows.

Metal test piece All test pieces: JIS G3141 (SP CC-B) Size 2 x 13 x 50 mm Zinc test piece: JIS H4321 (Animpan) Size 2 x 13 x 50 im Stability test method Sample 15 ml and 100 ml of water containing 1000 weight PPm of methyl chloroform. After thoroughly polishing the surface and thoroughly cleaning, place one dry iron, copper, or zinc test piece in a pressure-resistant glass bottle so that the top half of the test piece is exposed to the gas phase space and the bottom half is soaked overnight. , Seal tightly.

After processing at 60° C. for a predetermined time, the sample is cooled to room temperature.

The test piece was taken out, and its surface condition was divided into the part immersed in the liquid (hereinafter referred to as the liquid phase part) and the part exposed to the gas phase space (hereinafter referred to as the liquid phase part), and the surface conditions were observed. Corrosion resistance is ranked according to the following criteria.

Rank 1: Strong corrosion over the entire surface.

Rank 2: Partially strongly corroded or entirely thinly corroded.

Rank 3: Partially slightly corroded.

Rank 4: almost never changes.

Examples and Comparative Examples 1 A stability test was conducted for 48 hours using methyl chloroform to which the stabilizers shown in Table 1 were added as samples.

Examples and Comparative Example 2 Methyl chloroform, 1,4-dioxane 0.8% by volume, isobutyl alcohol O, 6% by volume, 1.2-
A stability test was conducted for 48 hours using a sample prepared by adding the stabilizer shown in Table 2 to methyl chloroform containing 0.4% by volume of butylene oxide.

The results are shown in Table 2.

As described above, among organotin compounds, compositions containing alkyltin carboxylic acids had good corrosion resistance against iron and zinc and exhibited excellent stability.

Claims (1)

[Claims] 1. A stabilized methylchloroform composition comprising an alkyltin carboxylate.