Patent Grant
6855211
This invention relates to a cleaning composition that has an unusually fast evaporation rate. In particular, it relates to a composition of benzotrifluoride and 1,1,2-trichloroethylene.
In manufacturing electronics, textiles, and apparel, it is necessary to remove grease, oil, and other soils left by machinery. A solvent that was widely used in industry for cleaning is 1,1,1-trichloroethane because it is non-flammable, has a low odor, readily dissolves greases and oils, and has a rapid evaporation rate, which is important for high speed processing. However, 1,1,1-trichloroethane has now been banned because it has found to be an ozone depletor. As a result, there is a great need in the industry for a substitute solvent that has some or all of the desirable properties of 1,1,1-trichloroethane, but which is not an ozone depletor.
We have discovered that a blend of benzotrifluoride (BTF) and 1,1,2-trichioroethylene (TCE) is an excellent substitute solvent for 1,1,1-trichloroethane. This blend is economical, readily dissolves oils and greases, is non-flammable, and has only a slight ethereal odor, which is not regarded as objectionable.
Its most important and unusual property, however, is its high evaporation rate. Not only does this blend dry almost as rapidly as 1,1,1-trichloroethane, but, very unexpectedly, it dries faster than either of its components! That is, the evaporation rate of the blend is higher than the evaporation rate of either benzotrifluoride or 1,1,2-trichloroethylene. As of now we have no explanation for this unusual phenomenon.
The composition of this invention is a blend of about 20 to about 80 wt % benzotrifluoride and about 20 to about 80 wt % TCE. Preferably, the blend is about 60 to 80 wt % benzotrifluoride and about 20 to about 40 wt % TCE because TCE is the more regulated component.
The blend can also include various optional ingredients such as up to about 1 wt % of a stabilizer for the TCE. A stabilizer is preferably present at a concentration of about 0.01 to about 1 wt %. Examples of suitable stabilizers include butylene oxide, ethyl acetate, diisopropyl amine, and epichlorohydrin. The preferred stabilizer is butylene oxide because it stays with the solvent during distillation.
The composition of this invention is a single phase composition and remains a liquid from about −25° C. to about 86° C. It can be used to clean electronics, textiles, and for contact cleaning and general cleaning. In addition, it can also be used as a solvent carrier for powdered metals, as an ink carrier, or in gravure printing. It can be used as a liquid wash or as an aerosol. Other uses will no doubt be apparent to those skilled in the art.
The following examples further illustrate this invention.
Benzotrifluoride (BTF) was mixed with TCE at various concentrations. The mixtures were tested for relative evaporation time using ASTM test D 1901-85. All tests were run in triplicates in a draft-free area. The following table summarizes the average evaporation rate with reference to butyl acetate (BuAc):
The above table shows that TCE concentrations of 25 to 75 wt % in BTF evaporate faster than either 100 wt % TCE or 100 wt % BTF.
The ability of various solvents to clean mineral oil was determined by weight difference. Approximately the same amounts, 30 mg, of mineral oil were brushed onto 7.6 by 1.3 cm (3 by ½) steel coupons. The coated coupons were weighed and placed into 20 ml of a test solvent for 30 seconds, 2 minutes, and 4 minutes. No agitation was provided. The coupons were removed from the solvents, allowed to air dry for at least 30 minutes, and weighed again. The difference in weight measured the extent of cleaning. This test was repeated three times for each solvent and cleaning time combination. The traditional cleaning solvent, 1,1,1-trichloroethane (TCA), was also included for the comparison.
The above table shows that the 50/50 mixture of BTF/TCE was the superior cleaning solvent.
Pantone Reflex Blue ink paste was added at 2-gram increments to 20 grams of various solvents in a glass vial. After each addition, the mixtures were stirred, visually examined for miscibility, and the dissolving rates were recorded. The additions were continued until no more ink paste was soluble or until a total of 20 to 22 grams of the ink paste had been added to the solvent. The following table gives the solvents tested and the results.
1Sold by Occidental Chemical Corporation as “OXSOL ®10”
2Sold by Occidental Chemical Corporation as “OXS0L ®100”
3Sold by Exxon as “Aromatic 100”
4Sold by Exxon as “Aromatic 150”
5Sold by Exxon as “Exxsol D 110”
The above table shows that BTF/TCE had the best ink dissolving rate of the solvents tested.
The present application is a division of parent application Ser. No. 08/644,144, filed May 10, 1996 now abandoned.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3546304 | Patron | Dec 1970 | A |
| 4232072 | Pardee | Nov 1980 | A |
| 4274829 | Zurbucher | Jun 1981 | A |
| 4578209 | Hisamoto et al. | Mar 1986 | A |
| 5242502 | Rowe | Sep 1993 | A |
| 5244507 | Rowe | Sep 1993 | A |
| 5744437 | Rowe et al. | Apr 1998 | A |
| 5756002 | Chen et al. | May 1998 | A |
| 5851435 | Chen et al. | Dec 1998 | A |
| 6020299 | Chen et al. | Feb 2000 | A |
| Number | Date | Country |
|---|---|---|
| WO 94 28196 | Dec 1994 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20020129840 A1 | Sep 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 08644144 | May 1996 | US |
| Child | 10073321 | US |
