JPS6318925B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to stabilized methylchloroform compositions. Methyl chloroform has a high dissolving power for oils and greases, is nonflammable, and is less toxic than solvents such as trichlorethylene and perchlorethylene. It is particularly useful for degreasing metals and cleaning textiles. Widely used as a solvent for processing and paints and adhesives. However, methyl chloroform is relatively unstable and reacts with metals, especially aluminum, zinc, and iron, when they are present, and chlorine is directly extracted and separation progresses in a chain reaction.The liquid becomes colored and eventually tars. substance,
It turns into black carbide. Unlike perchlorethylene, trichlorethylene, and 1,1,2-trichloroethane, which preferentially cause oxidative decomposition and catalytic dehydrochlorination, methylchloroform is unique in that it preferentially causes this type of decomposition reaction. It is. 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 some cases, it reacts with these metals and often corrodes them. Therefore, we first developed a technique for stabilizing methylchloroform to improve the corrosion resistance of iron and zinc in the presence of moisture.
-48128), glycerin monofatty acid ester (Japanese Patent Publication No. 57-48129), sulfosuccinic acid dialkyl ester (Japanese Patent Publication No. 57-48130), fatty acids with 5 or more carbon atoms (Japanese Patent Publication No. 58-12261), and alkyltin carbon He proposed the use of acid salts (Special Publication No. 58-5170). Furthermore, as a result of various studies, the present inventors have found that a methyl chloroform composition containing a metal soap can improve the corrosion resistance of iron and zinc, especially in the liquid phase where it constantly comes into contact with a solvent in the presence of water. I found it to be effective. That is, the stabilized composition proposed in the present invention is a stabilized methylchloroform composition characterized by containing one or more metal soaps selected from calcium, barium, zinc, and lead salts of higher fatty acids. The higher fatty acids constituting the metal soap used in the present invention refer to saturated and unsaturated fatty acids having 6 or more carbon atoms, including caproic acid, caprylic acid, 2-ethylhexylic acid, lauric acid, palmitic acid, stearic acid, and oleic acid. , linoleic acid, etc. Preferably 2-ethylhexylic acid, lauric acid,
It is a saturated fatty acid such as stearic acid. These higher fatty acid salts of calcium, barium, zinc, and lead may be used alone or in combination of two or more, such as a combination of zinc stearate and barium stearate, or a combination of lead stearate and calcium 2-ethylhexylate. May be used together. The amount of these compounds used can vary widely depending on the use of the composition and the conditions of use, but it is usually 5 ppm by weight based on methyl chloroform.
That's all. 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 paint component, it can be dispersed in addition to the solubility to obtain a high degree of stability, and its content is 5% by weight.
will reach even. 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. Used with stabilizers selected from 1,4-dioxane, dioxolane, trioxane, methylbutynol, tert-butanol, iso-butanol, tert-amyl alcohol, nitromethane, nitroethane, nitropropane, 1,2-butylene oxide, glycidol, etc. It will be done. Further, the metal soap generally has a low solubility in methyl chloroform, but when it is necessary to dissolve it uniformly, a method of heating and stirring for several minutes is used. Hereinafter, the effects of the present invention will be specifically explained using Examples and Comparative Examples. The amounts of stabilizers added in the tables of Examples and Comparative Examples below are based on the weight of methyl chloroform, and the metal test pieces and stability test methods are as follows. Metal test piece Iron test piece: JIS G3141 (SPCC-B) Size 2 x 13 x 50 mm Zinc test piece: JIS H4321 (Aenban) Size 2 x 13 x 50 mm Stability test piece 1000 weight against 15 ml sample and methyl chloroform
After thoroughly polishing the surface and thoroughly washing, place one dry iron or zinc test piece in a 100ml pressure-resistant glass bottle containing ppm of water, with the upper half of the test piece exposed to the gas phase space and the lower half exposed to the liquid. Place it so that it is submerged inside and seal it 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 no change. Examples and Comparative Example 1 A stability test was conducted for 48 hours using methyl chloroform to which the stabilizers shown in Table 1 were added as samples. The results are shown in Table 1.

[Table] Example and Comparative Example 2 0.8% by volume of 1,4-dioxane, 0.6% by volume of tert-amyl alcohol, 0.3% by volume of methylbutynol, 0.4% by volume of 1,2-butylene oxide based on methylchloroform A stability test was conducted for 48 hours using a sample prepared by adding the stabilizer shown in Table 2 to methyl chloroform containing . The results are shown in Table 2.

[Table] As described above, the composition of the present invention has good corrosion resistance against iron, zinc, etc. even in the presence of moisture, so it can be used not only for degreasing and cleaning of metals, but also for dry cleaning, which often comes into contact with various metals for a long time. It is advantageous for use as a solvent component in cleaning liquid compositions, solvent-based coating compositions, adhesive compositions, aerosol compositions, etc., and its industrial significance is extremely high.

Claims (1)

[Claims] 1. A stabilized methyl chloroform composition comprising one or more metal soaps selected from calcium, barium, zinc and lead salts of higher fatty acids.