JPH0144759B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to methylchloroform stabilizing compositions suitable for dry cleaning applications. Methyl chloroform has a high dissolving power for oils and greases, is flame retardant, and has less toxicity and air pollution than solvents such as trichlorethylene and verchlorethylene, so it is widely used as a metal degreasing and cleaning solvent. However, recently, it has been rapidly gaining attention as a dry cleaning solvent for clothing due to its particularly good finish such as texture. However, methylchloroform has a drawback in its chemical stability, and has a strong tendency to react with metals or their salts and decompose, so a stabilizer is essential when used industrially. For this reason, many stabilizers such as ethers, nitriles, nitroalkanes, and ketones have been studied, and as a result, for metal degreasing, JP-A-49-
As shown in 92004, sufficiently high stability has been achieved. However, there are still many obstacles to utilizing methyl chloroform stabilized by the stabilizer formulations proposed so far as a dry cleaning solvent. This is because dry cleaning requires harsher and more complex conditions than metal degreasing. That is, (1)
It is used for a long period of time with frequent distillation regeneration. (2) It is used in the presence of a considerable amount of water mixed in from the clothes being washed. (3) There is a constant loss of stabilizer, resulting in a low stabilizer concentration under actual cleaning work conditions. Nevertheless, it must be stable to the wide variety of metals that make up dry cleaning machines. In addition, it is also required that the cleaning properties are not adversely affected, such as weakening the cleaning power or back-contaminating the items to be washed. For example, if a large amount of stabilizer is added in an attempt to increase the stability against metals, dyes tend to elute and the items to be washed tend to yellow.
Therefore, for dry cleaning, the amount of stabilizer should generally be less than 8% by volume of the total composition, although it depends on the type of stabilizer. More preferably
Must be less than 5.5% by volume. The present inventor conducted research to obtain a methyl chloroform composition that is stable against various metals and has excellent cleaning properties under these constraints, and as a result, the inventors have developed a method for obtaining a methyl chloroform composition that is highly stable against various metals and has excellent cleaning properties. We have discovered what can be achieved and have arrived at the present invention. That is, the present invention provides 1,4-dioxane, 3
butyl alcohol, nitromethane and 1,2
-butylene oxide, and (1) the sum of 1,4-dioxane and nitromethane is 1.9 of the total composition;
(2) nitromethane is 1.4% by volume or more
- 0.5 times or more of dioxane, (3) 1,2-butylene oxide in a volume ratio of 0.2 to 1.5 times nitromethane, and (4) tertiary butyl alcohol in a volume ratio of 1,4-
(5) The total amount of 1,4-dioxane, tertiary butyl alcohol, nitromethane, and 1,2-butylene oxide is at least 0.6 times that of dioxane in the entire composition.
A methyl chloroform composition for dry cleaning characterized by having a content of 5.5% by volume or less. Methyl chloroform reacts violently with aluminum without an aluminum oxide film and is dangerous, so it must always be stable with aluminum. Dry cleaning solvents must also be stable to thin aluminum foils used as glitter on clothing. This can only be achieved satisfactorily if the total amount of nitromethane and 1,4-dioxane is 1.9% by volume or more, based on the total composition. From the standpoint of stability against aluminum, the ratio between nitromethane and 1,4-dioxane is not much of a problem, but it is stable against iron, which is the main component of dry cleaning machines, in the coexistence of water. requires 0.5 times or more of nitromethane by volume. When this amount is less than 0.5 times the amount, corrosion of iron increases significantly. Next, to provide excellent stability to the zinc used in the piping parts of dry cleaning machines,
1,2-butylene oxide should have a volume ratio of nitromethane of 0.2 to 1.5, preferably 0.3 to 1.0. Curiously, if this ratio is too large or too small, the stability toward zinc decreases.
Among the four stabilizer mixtures constituting the composition of the present invention, when nitromethane and 1,2-butylene oxide are in such a specific ratio, they exhibit particularly excellent stability against zinc. Although this is surprising, its mechanism of action has not yet been elucidated. On the other hand, in dry cleaning, among the cleaning properties, the relationship between detergency and anti-contamination properties is important. Generally, stains on clothing include both oil-soluble stains and water-soluble stains, but dry cleaning liquid made of methyl chloroform can remove oil-soluble stains with almost no problems due to its excellent solvent properties. However, coexisting water-soluble stains cannot always be completely removed. This problem can be considerably improved by the use and selection of surfactants, but even this is not sufficient. The compositions of the present invention can also be improved in this respect, providing excellent cleaning power and low back-fouling properties at the same time. It is unique in that it can only be achieved with a characteristic ratio of tertiary butyl alcohol to 1,4-dioxane in a volume ratio of 0.6 or more. When this ratio is less than 0.6, although excellent cleaning power can be provided, the reverse staining property also increases, and the object of the present invention cannot be achieved. As described above, the composition of the present invention exhibits improved properties not found in conventional compositions when used for dry cleaning, and is of extremely high value industrially. In addition, in order to facilitate comparison with the previously cited JP-A-49-92004, when the composition of the present invention is expressed in weight% and weight ratio, the total amount of stabilizer in the entire composition is approximately
The total amount of nitromethane and dioxane is 1.6% or less, and nitromethane is less than dioxane.
Butylene oxide is 0.55 times more than nitromethane.
0.15 times or more and 1.1 times or less, tertiary butyl alcohol is 0.47 times or more dioxane, nitromethane is 0.6%
It turns out that the above is true. The present invention will be explained in more detail below with reference to Examples, and the tests were carried out in accordance with the following method. Note that all percentages representing compositions indicate volume percentages based on the total composition. A. Preparation method of test solution The following operations were performed on sample solutions of methyl chloroform containing each stabilizer using an actual dry cleaning machine (Sanyo SCL-915). Charge 270 samples of sample solution into the machine's storage tank as an initial charge, then transfer 60 sample solutions from there to the washing drum for each wash, and add 2.5 kg each of cotton, wool, acrylic, and polyester white cloth to this. In addition, 300ml of soap commonly used for dry cleaning
was added and washing was performed for 5 minutes. A white cloth was used in this method to eliminate the rinsing step. After washing, the drained liquid was sent to a still and recycled by distillation. The regenerated liquid was returned to the liquid storage tank. After every 34 washing operations, the lost liquid volume is replenished with the sample solution and the washing operation is continued.
The distillation sludge was removed from the still every 10 times. When the washing operation was repeated 500 times in this way and an equilibrium state was reached, the sample solution was extracted from the storage tank and used as a test solution in various evaluation tests. B Evaluation Test Method B-1, Aluminum Squatch Test Pour 50ml of the test solution into a 100ml beaker and add an aluminum alloy specimen (JIS,
H4000, A2024P) and scratch the surface with a sharp awl three times in the length direction and twice in the perpendicular direction. The changes in the hit position are ranked as follows. Rank 1: No change occurs at all. Rank 2: A chemical change occurs, but it is temporary and the change stops immediately. Rank 3: Chemical changes continue, corrosion of the metal surface and coloring of the liquid progress. B-2. Iron corrosion test 200 ml of the test solution and 6 ml of water are placed in a 300 ml eggplant flask equipped with a reflux condenser. Mild steel piece (JIS G4051, S20C, dimensions 2 x 13 x 30 mm) that has been well polished and thoroughly washed and dried with acetone.
The specimen is immersed in the test solution and refluxed on a 90°C hot bath. After 30 hours, take out the mild steel piece, remove the rust with a 10% citric acid aqueous solution, and measure the weight change. The amount of corrosion of a mild steel piece is expressed as mdd using the following formula. mdd = 20.5 x (weight loss in mg) = mg/dm ² /day B-3, Zinc corrosion test 1 ml of the test solution saturated with water and a zinc piece (JIS H4321, Class 1, dimensions 2 x 2 x 12
mm) sealed in a small glass ampoule and heated to 175°C. Measure the time until corrosion of zinc starts. B-4. Cleaning power and reverse staining test A standard artificially contaminated cloth (Wool Surge) according to the Japan Oil Chemists' Association method was further treated with a 0.1% solution of methylene blue as an example of water-soluble stain, and the amount of adhesion to the cloth was 0.05. % was used as the contaminated cloth for this test. Four pieces of original cloth (each size, 5 x 10 cm) of the same quality as this contaminated cloth were placed in a cleaning bottle containing nine steel balls (diameter 6.5 mm) with the test solution.
Pour in with 400ml and use a laudaometer.
Treated for 10 minutes. The cleaning efficiency and reverse contamination rate were determined using the following equations. Cleaning efficiency (%) = reflectance of contaminated cloth after cleaning -
Reflectance of contaminated cloth before cleaning / Reflectance of original cloth − Reflectance of contaminated cloth before cleaning × 100 Reverse contamination rate (%) = Reflectance of original cloth before cleaning − Reflectance of original cloth after cleaning / Reflectance of original fabric before cleaning x 100 The reflectance is measured using Genbu Reflecto Meter.
Measured using GR-600. Example 1 Tests obtained according to the method described above from methyl chloroform sample solutions containing 1.5% tertiary butyl alcohol, 0.5% 1,2-butylene oxide, and various ratios of 1,4-dioxane and nitromethane. The liquid was subjected to an aluminum scratch test. The results are shown in Table 1. Ranks 2 and 1 in Table 1 pose no practical problem.

[Table] Example 2 From methyl chloroform sample solutions containing 2.05% tertiary butyl alcohol, 0.83% 1,2-butylene oxide, 1.31% 1,4-dioxane, and nitromethane in various ratios to 1,4-dioxane. An iron corrosion test was conducted on the sample solution obtained according to the method described above. The results are shown in Figure 1. As is clear from Figure 1, nitromethane/
When 1,4-dioxane (volume ratio) is greater than 0.5, the amount of corrosion of iron decreases rapidly. Example 3 2.0% 1,4-dioxysane, 1.0% tertiary butyl alcohol, and 1.2% or 1.5% total of nitromethane and 1,2-butylene oxide
Zinc corrosion tests were conducted on test solutions obtained according to the method described above from sample solutions of methyl chloroform containing various amounts of nitromethane and 1,2-butylene oxide. The results are shown in Figure 2. 1,2-butylene oxide/(1,2-butylene oxide + nitromethane) <volume ratio> is approximately 0.45
It can be seen that particularly excellent stability towards zinc is shown between 0.85 and 0.85. Converting this to the ratio of 1,2-butylene oxide/nitromethane is approximately
It will be 0.2 to 1.5. When in this range, the corrosion onset time is more than 50-60 minutes, and the zinc part of dry cleaning machine under actual usage conditions is 1
Almost no corrosion occurs for more than a year. Example 4 Contains 0.5% of 1,2-butylene oxide, 1.0% of nitromethane, and a total of 3.2% of both 1,4-dioxane and tertiary butyl alcohol,
Cleaning power and reverse staining tests were conducted on test solutions obtained according to the method described above from sample solutions with various ratios of dioxane and tertiary butyl alcohol. The results are shown in Figure 3. Tertiary butyl alcohol is 1,4-dioxane
Favorable cleaning properties are exhibited when the amount is 0.6 times or more, preferably 0.75 times or more.

[Brief explanation of drawings]

Figure 1 is a chart showing the test results of Example 2;
The figure is a chart showing the test results of Example 3, and FIG. 3 is a chart showing the test results of Example 4.

Claims (1)

[Scope of Claims] 1. Contains 1,4-dioxane, tertiary butyl alcohol, nitromethane and 1,2-butylene oxide, and (1) the total of 1,4-dioxane and nitromethane is 1.9 volume of the total composition. % or more (2) Nitromethane is 0.5 times or more by volume of 1,4-dioxane (3) 1,2-butylene oxide is 0.2 to 1.5 times by volume of nitromethane (4) Tertiary butyl alcohol is by volume (5) The total amount of 1,4-dioxane, tertiary butyl alcohol, nitromethane and 1,2-butylene oxide is 5.5% by volume or less of the total composition. A methyl chloroform composition for dry cleaning.