Cleaning solvent compositions exhibiting azeotrope-like behavior and their use

Abstract

A cleaning solvent composition comprises from about 70 to about 95.7 weight percent trans-dichloroethylene, from about 15 to about 3.8 weight percent heptafluorocyclopentane, and from about 15 to about 0.5 weight percent of methylperfluoroheptene ethers. The composition may comprise from about 88 to about 94.2 weight percent trans-dichloroethylene, from about 6 to about 3.8 weight percent heptafluorocyclopentane, and from about 6 to about 2 weight percent of methylperfluoroheptene ethers. A method for cleaning articles of soiling substances comprises contacting the articles with the solvent composition by any suitable means such as a spray delivered by a propellant gas, or by contact with liquid and/or vapor solvent compositions, as in a conventional vapor degreaser apparatus.

Claims

1. A solvent composition exhibiting azeotrope-like properties and comprising: from about 70 to about 95.7 weight percent trans-dichloroethylene; from about 15 to about 3.8 weight percent heptafluorocyclopentane; and from about 15 to about 0.5 weight percent methylperfluoroheptene ethers.

2. The solvent composition of claim 1 comprising: from about 88 to about 94.2 weight percent trans-dichloroethylene; from about 6 to about 3.8 weight percent heptafluorocyclopentane; and from about 6 to about 2 weight percent methylperfluoroheptene ethers.

3. The composition of claim 1 comprising: from about 91 to about 92.7 weight percent trans-dichloroethylene; from about 4.5 to about 3.8 weight percent heptafluorocyclopentane; and from about 4.5 to about 3.5 weight percent methylperfluoroheptene ethers.

4. The composition of claim 1 comprising: from about 70 to about 95.5 weight percent trans-dichloroethylene; from about 15 to about 4 weight percent heptafluorocyclopentane; and from about 15 to about 0.5 weight percent methylperfluoroheptene ethers.

5. The composition of claim 1 comprising: about 92 weight percent trans-dichloroethylene; about 4 weight percent heptafluorocyclopentane; and about 4 weight percent methylperfluoroheptene ethers.

6. The composition of claim 1 comprising: from about 88 to about 92 weight percent trans-dichloroethylene; from about 6 to about 4 weight percent heptafluorocyclopentane; and from about 6 to about 4 weight percent methylperfluoroheptene ethers.

7. The composition of claim 1 comprising: about 90 weight percent trans-dichloroethylene; about 5 weight percent heptafluorocyclopentane; and about 5 weight percent methylperfluoroheptene ethers.

8. A method for cleaning soiling substances from metal, ceramic and synthetic polymer articles comprising: contacting one or more of the articles with a solvent composition having azeotrope-like properties, the composition comprising: from about 70 to about 95.7 weight percent trans-dichloroethylene; from about 15 to about 3.8 weight percent heptafluorocyclopentane; from about 15 to about 0.5 weight percent methylperfluoroheptene ethers; and removing the composition from the one or more articles.

9. The method of claim 8 wherein the composition comprises: from about 88 to about 94.2 weight percent trans-dichloroethylene; from about 6 to about 3.8 weight percent heptafluorocyclopentane; and from about 6 to about 2 weight percent methylperfluoroheptene ethers.

10. The method of claim 8 wherein the composition comprises: from about 91 to about 92.7 weight percent trans-dichloroethylene; from about 4.5 to about 3.8 weight percent heptafluorocyclopentane; and from about 4.5 to about 3.5 weight percent methylperfluoroheptene ethers.

11. The method of claim 8 wherein the composition comprises: from about 70 to about 95.5 weight percent trans-dichloroethylene; from about 15 to about 4 weight percent heptafluorocyclopentane; and from about 15 to about 0.5 weight percent methylperfluoroheptene ethers.

12. The method of claim 8 wherein the composition comprises: about 92 weight percent trans-dichloroethylene; about 4 weight percent heptafluorocyclopentane; and about 4 weight percent methylperfluoroheptene ethers.

13. The method of claim 8 wherein the composition comprises: from about 88 to about 92 weight percent trans-dichloroethylene; from about 6 to about 4 weight percent heptafluorocyclopentane; and from about 6 to about 4 weight percent methylperfluoroheptene ethers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph plotting the change in composition of a cleaning solvent embodiment of the present invention measured in the rinse sump of a vapor degreaser against the time period of repeated distillation and condensation; and

(2) FIG. 2 is a graph identical to that of FIG. 1 except that the change in composition is measured in the boil sump of the vapor degreaser.

DETAILED DESCRIPTION OF THE INVENTION AND SPECIFIC EMBODIMENTS THEREOF

(3) The following abbreviations, trademarks and trade names have the following meanings, whether used in the singular or plural form. TDCE. Trans-Dichloroethylene. Chemical Abstracts Number (CAS #) 156-60-5. XF. The hydrofluorocarbon, 2,3-dihydrodecafluoropentane (HFC 43-10me) [Tradename Vertrel XF]. CAS #1384-95-42. HFX-110. Methylperfluoroheptene ethers; Tradename HFX-110. CAS #Proprietary. HFCP. 1,1,2,2,3,3,4-Heptafluorocyclopentane. Tradename Zeorora. CAS #15290-77-4. HFEs. Hydrofluoroethers such as HFE 7100, CAS #163702-08-7 and 163702-07-6. Vertrel SFR. A blend of 67% trans-dichloroethylene, 18% 2,3-dihydrodecafluoropentane (HFC 43-10me); 12% heptafluorocyclopentane; 3% methanol. This material has a boiling point of 106 F. (41.1 C.) and is available from Chemours Corporation of Wilmington, Del. SION. A blend of 95.2% trans-dichloroethylene, 4.0% methylperfluoroheptene ethers (HFX-110) and 0.8% 2,3-dihydrodecafluoropentane (HFC 43-10me). This material has a boiling point of 121 F. (49.4 C.) and is available from Chemours Corporation of Wilmington, Del. CMS. A blend of 41.5% trans-dichloroethylene, 18% HFC 365mfc, 37% 2,3-dihydrodecafluoropentane (HFC 43-10me), 3.5% methanol. This material has a boiling point of 97 F. (36.1 C.) and is available from MicroCare Corporation of New Britain, Conn., the applicant herein. MCA. A blend of 62% trans-dichloroethylene, 38% 2,3-dihydrodecafluoropentane (HFC 43-10me). This material has a boiling point of 102 F. (38.9 C.) and is available from Chemours Corporation of Wilmington, Del. MEOH. Methyl alcohol. SDG. A blend of 83% trans-dichloroethylene, 7% 2,3-dihydrodecafluoropentane (HFC 43-10me); 10% hexafluorocyclopentane. Bp 109F. This material has a boiling point of 109 F. (42.8 C.) and is available from Chemours Corporation of Wilmington, Del. 10-122-2 and 10-93-2. These are the designations applied respectively to two particularly effective embodiments of the present invention. It is a blend of 92% trans-dichloroethylene, 4% heptafluorocyclopentane and 4% methylperfluoroheptene ethers.

(4) Standard Test Procedure. Trials were conducted in standard 2-sump vapor degreasers or in bench top simulation using a dual bulb apparatus made using a standard solvent still head with collection flask and sampling port on the boil flask. Samples from various locations and times are analyzed by gas chromatography using an Agilent Corporation DB-200 capillary column (trifluoropropyl methyl dimethyl siloxane stationary phase) and an FID detector. The following examples report the results of trials conducted pursuant to this Standard Procedure. The Vertrel Sion material, referred to below, is currently marketed under the tradename Opteon SF79.

COMPARATIVE EXAMPLE 1

Fractionation of Vertrel SFR in a Vapor Degreaser

(5) TABLE-US-00001 Composition of Vertrel SFR Over Time in Branson B-452R Degreaser % TDCE % HFCP % XF % MeOH Virgin (Drum) 67.7 12.2 17.3 2.8 Time Boil Rinse Boil Rinse Boil Rinse Boil Rinse Distilled Sump Sump Sump Sump Sump Sump Sump Sump 1 hour 75.8 68 16.5 12.2 6.6 16.7 0.9 2.9 2 hours 76.4 67.6 16.8 12.1 5.9 17.2 0.8 3 5 hours 77.3 68.3 16.4 11.7 5.4 16.9 0.7 3 7 hours 77.3 68.3 16.5 11.7 5.3 16.9 0.7 3 9 hours 76.9 67.9 16.9 12.1 5.4 16.9 0.7 2.9 12 hours 77.9 68.3 15.9 11.5 5.3 17.1 0.7 3 17 hours 78.2 68.7 15.6 11.1 5.3 17.1 0.7 3.1

(6) It can be seen that this blend of solvents, although remaining substantially azeotrope-like in behavior, changes its vapor composition quickly and dramatically. The ratios partition between the boil and rinse sump with the TDCE levels changing by more than 10% from the original values (67.7 weight % to 78.2 weight %).

COMPARATIVE EXAMPLE 2

Fractionation of Vertrel Sion

(7) TABLE-US-00002 Composition of Vertrel Sion over time in a vapor degreaser % TDCE % HFX-110 % XF Virgin (Drum) 95.1 4.1 0.8 Time Boil Rinse Boil Rinse Boil Rinse Distilled Sump Sump Sump Sump Sump Sump 4.5 hours 95.64 95.05 4.23 4.03 0.13 0.92 13 hours 95.63 95.29 4.27 4.08 0.1 0.63 21.5 hours 95.61 95.28 4.24 4.1 0.15 0.62 29.5 hours 95.6 95.35 4.27 4.1 0.13 0.55

(8) It can be seen that this product blend also changes ratio between the boil and rinse flasks. Most dramatically, the Vertrel XF which is present to improve the non-flammable characteristic of the blend, has been substantially depleted in the boil sump.

COMPARATIVE EXAMPLE 2A

Distillation in Laboratory Glassware of a Solvent Composition Containing an Initial Low Percentage (2.29 Weight Percent) of Heptafluorocyclopentane (HFCP)

(9) TABLE-US-00003 12-302-1 Time % % % Boil Temp (hours) Trans HFCP MPHE ( C.) Total Initial 0 93.74 2.29 3.97 100 Fraction 1 1 92.8 3.94 3.26 50 100 Fraction 2 2 92.62 4.15 3.23 49 100 Fraction 3 2.5 92.77 3.98 3.25 50.5 100 Fraction 4 3.5 92.94 3.73 3.33 50.5 100 Fraction 5 4.5 93.42 2.96 3.62 51 100 Fraction 6 5.5 93.62 2.67 3.71 50 100 Fraction 7 6.5 93.57 2.76 3.67 50 100 Fraction 8 8 93.79 2.42 3.79 51.5 100 Fraction 9 9 93.9 2.38 3.72 51 100 Fraction 10 10 94.33 1.61 4.06 50 100 Fraction 11 11.5 94.6 1.02 4.38 50 100 Fraction 12 12.5 94.78 0.59 4.63 50 100

(10) 12-302-1. Distillation over a period of 11.5 hours shows that that HFCP composition was reduced from an initial amount of 2.29 weight percent to 1.02 weight percent. This is a reduction in HFCP content of the original composition of 1.02/2.29=44.5%. At 12.5 hours of distillation the reduction in HFCP content is 25.8%. At various times of distillation both the HFCP and the methylperfluoroheptane ethers (MPHE) contents fluctuated significantly showing that the low HFCP composition does not possess azeotrope-like characteristics over only 12.5 hours of distillation, even though the trans-dichloroethylene content remained fairly stable.

COMPARATIVE EXAMPLE 2B

Distillation in Laboratory Glassware of a Solvent Composition Containing an Initial Low Percentage (3.03 Weight Percent) of Heptafluorocyclopentane (HFCP)

(11) TABLE-US-00004 12-307-1 Time % % % Boil Temp (hours) Trans HFCP MPHE ( C.) Total Initial 0 93.01 3.03 3.96 100 Fraction 1 1 91.03 6.22 2.75 50.5 100 Fraction 2 2 91.12 6.08 2.8 50.5 100 Fraction 3 3 91.83 5 3.17 50.5 100 Fraction 4 4 92.04 4.69 3.27 50.5 100 Fraction 5 5 92.7 3.76 3.54 51.5 100 Fraction 6 6 92.99 3.33 3.68 51 100 Fraction 7 7 93.31 2.83 3.86 50.5 100 Fraction 8 8 93.65 2.28 4.07 52 100 Fraction 9 10 94.01 1.08 4.91 52 100

(12) 12-307-1. Example 2B shows that after two hours of distillation an initial content of 3.03 weight percent HFCP increased to 6.08 weight percent, an increase of 6.08/3.03 or 100 percent. The HFCP content diminished with additional distillation. After 10 hours of distillation the HFCP content was 1.08 weight percent, a reduction of 1.08/3.03=36 percent. This low initial HFCP content blend did not demonstrate azeotrope-like characteristics.

COMPARATIVE EXAMPLE 2C

Distillation in Laboratory Glassware of a Solvent Composition Containing an Initial Low Percentage (3.51 Weight Percent) of Heptafluorocyclopentane (HFCP)

(13) TABLE-US-00005 12-307-2 Time % % % Boil Temp (hours) Trans HFCP MPHE ( C.) Total Initial 0 92.49 3.51 4 100 Fraction 1 1 91.41 5.48 3.11 49.5 100 Fraction 2 2.5 90.63 6.71 2.66 49.5 100 Fraction 3 3.5 91.43 5.46 3.11 50 100 Fraction 4 5 91.68 5.16 3.16 50 100 Fraction 5 6 91.36 5.6 3.04 50 100 Fraction 6 7.25 92.04 4.55 3.41 50 100 Fraction 7 8.25 92.88 3.19 3.93 53 100 Fraction 8 9.25 93.43 2.39 4.18 53 100 Fraction 9 11.25 93.56 2.19 4.25 52.5 100 Fraction 10 12.75 93.94 1.46 4.6 50 100

(14) 12-307-2. A solvent composition with an initial HFCP content of 3.51 weight percent showed a significant increase in HCFP after only one hour of distillation, to 5.48 weight percent, an increase of 5.48/3.51 or 59 percent. At 2.5 hours of distillation the HFCP content had increased to 6.71 weight percent, an increase of 6.71/3.51 or 91 percent. The MPHE content was reduced at these times of distillation. By 7.25 hours of distillation the HFCP content had reduced to 4.55 weight percent and the MPHE content had recovered to 3.41 weight percent. At 12.75 hours of distillation, the HFCP content was reduced to 1.46 weight percent. Like comparative examples 2A and 2B, comparative example 2C shows that a low initial HFCP content does not provide azeotrope-like characteristics even after only 12.75 hours of distillation.

EXAMPLE 3

Formulation of an Embodiment (Designated 10-122-2) of the Present Invention

(15) Part ADistillation in a Vapor Degreaser

(16) TABLE-US-00006 Composition of Prototype 10-122-2 Over Time in Branson B-452R Degreaser % TDCE % HFCP % HFX-110 Virgin (Drum) 92.0 4.0 4.0 Time Boil Rinse Boil Rinse Boil Rinse Distilled Sump Sump Sump Sump Sump Sump 1 hour 92.1 91.7 3.5 4.7 4.3 3.6 2 hours 92.2 91.7 3.5 4.7 4.3 3.6 5 hours 92 91.6 3.5 4.7 4.5 3.7 6 hours 92 91.6 3.5 4.7 4.5 3.7 24 hours 92 91.6 3.3 4.6 4.7 3.8 36 hours 92.1 91.7 3.3 4.6 4.6 3.7 4 days 92.1 91.8 3.2 4.5 4.7 3.7 5 days 92 91.7 3.2 4.5 4.7 3.8 6 days 91.9 91.7 3.3 4.5 4.8 3.8 7 days 91.9 91.6 3.3 4.5 4.8 3.9 Averages 92.0 91.7 3.4 4.6 4.6 3.7

(17) As shown by Part A of Example 3, the present invention quickly redistributes ratios to a small degree, changing the composition only slightly over a week of distillation. The cleaning power and non-flammable behavior is maintained in all locations of the vapor degreaser.

(18) Part BDistillation in Laboratory Glassware Simulating a Vapor Degreaser

(19) TABLE-US-00007 Prototype 10-122-2 Vapor Degreaser Simulation Total Time Distilled (hours) % TDCE % HFCP % HFX-110 0 92.0 4.0 4.0 1 91.9 4.9 3.2 2 92.2 4.4 3.3 3 92.3 4.3 3.4 4 92.3 4.2 3.5 5 92.3 4.1 3.6

(20) The results of Part B of Example 3, in which distillation was carried out in laboratory glassware simulating operation in a vapor degreaser, shows excellent results. Over 5 hours of distillation resulted in only a very small change.

(21) FIGS. 1 and 2 are graphs plotting on the vertical axis the weight percent of each component in the cleaning solvent embodiment of the present invention designated 10-122-2, and on the horizontal axis the duration in hours of distillation and condensation in a Branson VDG. As noted above, the composition of 10-122-2 is 92 wt percent trans-dichloroethylene, 4 wt % heptafluorocyclopentane, and 4 wt % methylperfluoroheptene ethers. FIG. 1 shows the measured quantities in the rinse sump of the Branson B-452R vapor degreaser and FIG. 2 shows the measured composition in the boil sump of the Branson B-452 vapor degreaser. As shown in the Figures, the change in composition after about 36 hours of distillation and condensation is minimal.

(22) As the above examples show, azeotrope-like characteristics of solvent compositions comprising trans-1,2-dichloroethylene (TDCE), heptafluorocyclopentane (HFCP) and methylperfluoroheptene ethers (MEPH or HFX-110) require more than about 3.5 weight percent HFCP, preferably at least about 3.8 weight percent HFCP, more preferably at least about 4 weight percent, in the initial composition in order to maintain azeotrope-like characteristics for a significant time of use.

EXAMPLE 4

Range of Ratios Showing Azeotrope-Like Behavior

(23) TABLE-US-00008 Embodiment of Comparative Comparative the Invention Vertrel Sion 10-93-2 10-122-2 (95% TDCE/ (95% TDCE/ (92% TDCE/ 4.2% HFX-110/ 2% HFCP/ 4% HFCP/ 0.8% XF) 3% HFX-110) 4% HFX-110) Boiling Point of 118 F. 118 F. 118 F. Lowest-Boiling Component (TDCE) Theoretical Boil- 122.7 F. 122.5 F. 125 F. ing Point (Based on Calculation) Boiling Point 117.8 F. 117-117.5 F. 117 F. Measured with 9F-86 Hg thermometer

(24) Comparative example 10-93-2, with an initial content of 2 weight percent heptafluorocyclopentane shows an actual boiling point lower than that of the lowest boiling component, and therefore lower than that of any pure component of the blend. However, as shown by the above comparative examples, the low initial content (2 percent by weight) of heptafluorocyclopentane causes a loss of azeotrope-like behavior after a period of distillation.

(25) The boiling points across the tabulated ranges of composition remain below any of the individual solvents demonstrating azeotrope-like behavior.

EXAMPLE 5

(26) The present invention stays non-flammable in all compartments of a vapor degreater versus the fractionated boil sump of Vertrel Sion that becomes flammable.

EXAMPLE 6

(27) The non-flammable aerosol version of the present invention was tested for flammability versus a Vertrel Sion aerosol. The latter failed the flame extension test at 36 inches whereas the composition in accordance with an embodiment of the present invention passed.

(28) TABLE-US-00009 GHS Flame Extension Test 6 inches 36 inches 80% 10-122-2/20% PASS PASS HFC134a propellant 80% Vertrel Sion/20% PASS FAIL HFC134a propellant

(29) The improved non-flammability of the invention over the commercial product is demonstrated.

(30) While the invention has been described in detail with reference to specific embodiments, it will be appreciated that numerous variations may be made to the described embodiment, which variations nonetheless lie within the scope of the present invention.