Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/50—Solvents
  • C11D7/5036—Azeotropic mixtures containing halogenated solvents
  • C11D7/5068—Mixtures of halogenated and non-halogenated solvents
  • C11D7/5077—Mixtures of only oxygen-containing solvents
  • C11D7/5081—Mixtures of only oxygen-containing solvents the oxygen-containing solvents being alcohols only
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/50—Solvents
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
  • C23G5/02—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents
  • C23G5/028—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing halogenated hydrocarbons
  • C23G5/02809—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing halogenated hydrocarbons containing chlorine and fluorine
  • C23G5/02825—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing halogenated hydrocarbons containing chlorine and fluorine containing hydrogen
  • C23G5/02829—Ethanes
  • C23G5/02832—C2H3Cl2F

Definitions

• This invention relates to azeotrope-like mixtures of 1,1-dichloro-1-fluoroethane; ethanol; and nitromethane. These mixtures are useful in a variety of vapor degreasing, cold cleaning and solvent cleaning applications including defluxing.
• Vapor degreasing and solvent cleaning with fluorocarbon based solvents have found widespread use in industry for the degreasing and otherwise cleaning of solid surfaces, especially intricate parts and difficult to remove soils.
• vapor degreasing or solvent cleaning consists of exposing a room temperature object to be cleaned to the vapors of a boiling solvent. Vapors condensing on the object provide clean distilled solvent to wash away grease or other contamination. Final evaporation of solvent from the object leaves behind no residue as would be the case where the object is simply washed in liquid solvent.
• the conventional operation of a vapor degreaser consists of immersing the part to be cleaned in a sump of boiling solvent which removes the bulk of the soil, thereafter immersing the part in a sump containing freshly distilled solvent near room temperature, and finally exposing the part to solvent vapors over the boiling sump which condense on the cleaned part.
• the part can also be sprayed with distilled solvent before final rinsing.
• Vapor degreasers suitable in the above-described operations are well known in the art.
• Sherliker et al. in U.S. Patent 3,085,918 disclose such suitable vapor degreasers comprising a boiling sump, a clean sump, a water separator, and other ancillary equipment.
• Cold cleaning is another application where a number of solvents are used.
• the soiled part is either immersed in the fluid or wiped with rags or similar objects soaked in solvents and allowed to air dry.
• Fluorocarbon solvents such as trichlorotrifluoroethane
• Trichlorotrifluoroethane has been found to have satisfactory solvent power for greases, oils, waxes and the like. It has therefore found widespread use for cleaning electric motors, compressors, heavy metal parts, delicate precision metal parts, printed circuit boards, gyroscopes, guidance systems, aerospace and missile hardware, aluminum parts and the like.
• azeotrope or azeotrope-like compositions including the desired fluorocarbon components such as trichlorotrifluoroethane which include components which contribute additionally desired characteristics, such as polar functionality, increased solvency power, and stabilizers.
• Azeotropic or azeotrope-like compositions are desired because they do not fractionate upon boiling. This behavior is desirable because in the previously described vapor degreasing equipment with which these solvents are employed, redistilled material is generated for final rinse-cleaning. Thus, the vapor degreasing system acts as a still.
• solvent composition exhibits a constant boiling point, i.e., is azeotrope-like, fractionation will occur and undesirable solvent distribution may act to upset the cleaning and safety of processing.
• Preferential evaporation of the more volatile components of the solvent mixtures which would be the case if they were not azeotrope-like, would result in mixtures with changed compositions which may have less desirable properties, such as lower solvency towards soils, less inertness towards metal, plastic or elastomer components, and increased flammability and toxicity.
• hydrochlorofluorocarbons such as 1,1-dichloro-1-fluoroethane (HCFC-141b)
• HCFC-141b 1,1-dichloro-1-fluoroethane
• HCFC-141b is known to be useful as a solvent.
• HCFC-141b has a boiling point of about 32°C.
• Aerosol products utilize a propellant gas or mixture of propellant gases, preferably in a liquified gas rather than a compressed gas state, to generate sufficient pressure to expel the active ingredients, i.e. product concentrates such as solvents, from the container upon opening of the aerosol valve.
• the propellants may be in direct contact with the solvent, as in most conventional aerosol systems, or may be isolated from the solvent, as in barrier-type aerosol systems.
• Kokai Patent Publication 136,982 published May 30, 1989 discloses a buff-grinding cleaning agent of 25 weight percent ethanol and 75 weight percent of an azeotropic composition of 25 weight percent 1,1-dichloro-1-fluoroethane and 50 weight percent 1,1-dichloro-2,2,2-trifluoroethane.
• Kokai Patent Publication 137,253, published May 30, 1989 discloses a resist developing agent of 25 weight percent ethanol and 75 weight percent of an azeotropic composition of 25 weight percent 1,1-dichloro-1-fluoroethane and 50 weight percent 1,1-dichloro-2,2,2-trifluoroethane.
• Kokai Patent Publication 137,259 discloses a resist separating agent of 15 weight percent ethanol, 10 weight percent alkyl benzene sulfonic acid, and 75 weight percent of an azeotropic composition of 25 weight percent 1,1-dichloro-1-fluoroethane and 50 weight percent 1,1-dichloro-2,2,2-trifluoroethane.
• Kokai Patent Publication 138,300 discloses a flux cleaning agent of 25 weight percent methanol and 75 weight percent of an azeotropic composition of 25 weight percent 1,1-dichloro-1-fluoroethane and 50 weight percent 1,1-dichloro-2,2,2-trifluoroethane.
• Kokai Patent Publication 139,104 discloses a solvent of 5 weight percent trichloroethylene, 20 weight percent ethanol, and 75 weight percent of an azeotropic composition of 25 weight percent 1,1-dichloro-1-fluoroethane and 75 weight percent 1,1-dichloro-2,2,2-trifluoroethane.
• Kokai Patent Publication 139,861 published June 1, 1989, discloses a dry-cleaning agent of 25 weight percent ethanol and 75 weight percent of an azeotropic composition of 25 weight percent 1,1-dichloro-1-fluoroethane and 75 weight percent 1,1-dichloro-2,2,2-trifluoroethane.
• Another object of the invention is to provide novel environmentally acceptable solvents for use in the aforementioned applications.
• novel mixtures comprising from 95.5 to 99.49 weight percent of 1,1-dichloro-1-fluoroethane; from 0.5 to 3.5 weight percent of ethanol; and from 0.01 to 1.0 weight percent of nitromethane which boil at 32.8°C ⁇ 0.5°C at 760 mm Hg (101 kPa).
• the azeotrope-like compositions of the invention comprise from 96.1 to 99.05 weight percent of 1,1-dichloro-1-fluoroethane; from 0.9 to 3.0 weight percent of ethanol; and from 0.05 to 0.9 weight percent of nitromethane.
• the azeotrope-like compositions of the invention comprise from 97.1 to 98.75 weight percent of 1,1-dichloro-1-fluoroethane; from 1.2 to 2.0 weight percent of ethanol; and from 0.05 to 0.9 weight percent of nitromethane.
• azeotrope-like is used herein for the mixtures of the invention because in the claimed proportions, the compositions of 1,1-dichloro-1-fluoroethane, ethanol, and nitromethane are constant-boiling or essentially constant-boiling and for some reason, which is not fully understood, remain or hang together in a vapor degreaser.
• compositions within the indicated ranges, as well as certain compositions outside the indicated ranges, are azeotrope-like, as defined more particularly below.
• compositions with the indicated ranges, as well as certain compositions outside the indicated ranges are azeotrope-like, as defined more particularly below.
• thermodynamic state of a fluid is defined by four variables: pressure, temperature, liquid composition and vapor composition, or P-T-X-Y, respectively.
• An azeotrope is a unique characteristic of a system of two or more components where X and Y are equal at the stated P and T. In practice, this means that the components of a mixture cannot be separated during distillation, and therefore are useful in vapor phase solvent cleaning as described above.
• azeotrope-like composition is intended to mean that the composition behaves like an azeotrope, i.e. has constant-boiling characteristics or a tendency not to fractionate upon boiling or evaporation.
• the composition of the vapor formed during boiling or evaporation is identical or substantially identical to the original liquid composition.
• the liquid composition if it changes at all, changes only to a minimal or negligible extent. This is to be contrasted with non-azeotrope-like compositions in which during boiling or evaporation, the liquid composition changes to a substantial degree.
• one way to determine whether a candidate mixture is "azeotrope-like" within the meaning of this invention is to distill a sample thereof under conditions (i.e. resolution - number of plates) which would be expected to separate the mixture into its separate components. If the mixture is non-azeotrope-like, the mixture will fractionate, i.e. separate into its various components with the lowest boiling component distilling off first, and so on. If the mixture is azeotrope-like, some finite amount of a first distillation cut will be obtained which contains all of the mixture components and which is constant-boiling or behaves as a single substance. This phenomenon cannot occur if the mixture is not azeotrope-like, i.e. it does not behave like an azeotrope. Of course, upon distillation of an azeotrope-like composition such as in a vapor degreaser, the true azeotrope will form and tend to concentrate.
• azeotrope-like compositions there is a range of compositions containing the same components in varying proportions which are azeotrope-like or constant-boiling. All such compositions are intended to be covered by the term azeotrope-like or constant-boiling as used herein.
• azeotrope-like or constant-boiling As an example, it is well known that at differing pressures, the composition of a given azeotrope-like composition will vary at least slightly as does the boiling point of the composition.
• an azeotrope-like composition of A and B represents a unique type of relationship but with a variable composition depending on temperature and/or pressure.
• the mixtures boil within ⁇ 0.5°C (at 760 mm Hg (101 kPa)) of the 32.8°C boiling point.
• the boiling point of the azeotrope-like composition will vary with the pressure.
• azeotrope-like compositions of the invention are useful as solvents in a variety of vapor degreasing, cold cleaning and solvent cleaning applications including defluxing.
• the azeotrope-like compositions of the invention may be used to clean solid surfaces by treating said surfaces with said compositions in any manner well known to the art such as by dipping or spraying or use of conventional degreasing apparatus.
• the azeotrope-like compositions are used to clean solid surfaces by spraying the surfaces with the compositions
• the azeotrope-like compositions are sprayed onto the surfaces by using a propellant.
• the propellant is selected from the group consisting of hydrocarbons, chlorofluorocarbons, hydrochlorofluorocarbon, hydrofluorocarbon, dimethyl ether, carbon dioxide, nitrogen, nitrous oxide, methylene oxide, air, and mixtures thereof.
• Useful hydrocarbon propellants include isobutane, butane, propane, and mixtures thereof; commercially available isobutane, butane, and propane may be used in the present invention.
• Useful chlorofluorocarbon propellants include trichlorofluoromethane (known in the art as CFC-11), dichlorodifluoromethane (known in the art as CFC-12), 1,1,2-trichloro-1,2,2-trifluoroethane (known in the art as CFC-113), and 1,2-dichloro-1,1,2,2-tetrafluoroethane (known in the art as CFC-114); commercially available CFC-11, CFC-12, CFC-113, and CFC-114 may be used in the present invention.
• Useful hydrochlorofluorocarbon propellants include dichlorofluoromethane (known in the art as HCFC-21), chlorodifluoromethane (known in the art as HCFC-22), 1-chloro-1,2,2,2-tetrafluoroethane (known in the art as HCFC-124), 1,1-dichloro-2,2-difluoroethane (known in the art as HCFC-132a), 1-chloro-2,2,2-trifluoroethane (known in the art as HCFC-133), and l-chloro-1,1-difluoroethane (known in the art as HCFC-142b); commercially available HCFC-21, HCFC-22, and HCFC-142b may be used in the present invention.
• HCFC-124 may be prepared by a known process such as that taught by U.S. Patent 4,843,181
• HCFC-133 may be prepared by a known process such as that taught by U.S
• Useful hydrofluorocarbon propellants include trifluoromethane (known in the art as HFC-23), 1,1,1,2-tetrafluoroethane (known in the art as HFC-134a), and 1,1-difluoroethane (known in the art as HFC-152a); commercially available HFC-23 and HFC-152a may be used in the present invention. Until HFC-134a becomes available in commercial quantities, HFC-134a may be made by a known method such as that disclosed by U.S. Patent 4,851,595. More preferred propellants include hydrochlorofluorocarbons, hydrofluorocarbons, and mixtures thereof. The most preferred propellants include chlorodifluoromethane and 1,1,1,2-tetrafluoroethane.
• the 1,1-dichloro-1-fluoroethane; ethanol; and nitromethane components of the novel solvent azeotrope-like compositions of the invention are known materials.
• the materials should be used in sufficiently high purity so as to avoid the introduction of adverse influences upon the desired properties or constant-boiling properties of the system.
• a vapor phase degreasing machine was charged with a preferred mixture in accordance with the invention, comprising about 98.5 weight percent of HCFC-141b, about 1.2 weight percent of ethanol, and about 0.3 weight percent of nitromethane.
• the mixture was evaluated for its constant boiling or non-segregating characteristics.
• the vapor phase degreasing machine utilized was a small water-cooled, three-sump vapor phase degreaser which represents a type of system configuration comparable to machine types in the field today which would present the most rigorous test of solvent segregating behavior.
• the degreaser employed to demonstrate the invention contained two overflowing rinse-sumps and a boil-sump.
• the boil-sump and the still were electrically heated, and each contained a low-level shut-off switch.
• Solvent vapors in both the degreaser and the still were condensed on water-cooled stainless-steel coils.
• the still was fed by gravity from the boil-sump. Condensate from the still was returned to the first rinse-sump, also by gravity.
• the capacity of the unit was approximately 5.68 litre (1.5 gallons).
• This degreaser was very similar to degreasers which are commonly used in commercial establishments.
• the solvent charge was brought to reflux and the compositions in the condensate sump containing the clear condensate from the still, the work sump containing the overflow from the condensate sump, the boil sump where the overflow from the work sump is brought to the mixture boiling points, and the still were determined with a Perkin Elmer Sigma 3 gas chromatograph.
• the temperature of the liquid in all the sumps was monitored with thermocouple temperature sensing devices accurate to ⁇ 0.2°C. Refluxing was continued for about 30 hours and boil and condensate sump compositions were monitored throughout this time.
• a mixture was considered constant-boiling or non-segregating if the maximum concentration difference between sumps for any mixture component was ⁇ 2 sigma around the mean value.
• Sigma is a standard deviation unit and it is our experience from many observations of vapor degreaser performance that commercial "azeotrope-like" vapor phase degreasing solvents exhibit at least a ⁇ 2 sigma variation in composition with time and yet produce very satisfactory non-segregating cleaning behavior.
• Example 1 was repeated except that the vapor phase degreasing machine was charged with another preferred mixture in accordance with the invention, comprising about 97.7 weight percent of HCFC-141b, about 2.0 weight percent of ethanol, and about 0.3 weight percent of nitromethane.
• a 5-plate Oldershaw distillation column with a cold water condensed automatic liquid dividing head was used for this example.
• the distillation column was charged with HCFC-141b, ethanol, and nitromethane in the amounts indicated in Table III below for the starting material.
• Each composition was heated under total reflux for about an hour to ensure equilibration.
• a reflux ratio of 5:1 was employed for this particular distillation.
• Approximately 50 percent of the original charges were collected in four similar-sized overhead fractions.
• the compositions of these fractions were analyzed using gas chromatography. The averages of the distillate fractions and the overhead temperatures are quite constant within the uncertainty associated with determining the compositions, indicating that the mixtures are constant-boiling or azeotrope-like.
• Performance studies are conducted to evaluate the solvent properties of the azeotrope-like compositions of the invention. Specifically, metal coupons are cleaned using the present azeotrope-like composition of Example 1 as solvent. The metal coupons are soiled with various types of oils and heated to 93°C so as to partially simulate the temperature attained while machining and grinding in the presence of these oils.
• the metal coupons thus treated were degreased in a simulated vapor phase degreaser machine. Condenser coils are kept around the lip of a cylindrical vessel to condense the solvent vapor which then drips down to the vessel. The metal coupons are held in the solvent vapor and rinsed for a period of 15 seconds to 2 minutes depending upon the oils selected.
• the cleaning performance of the azeotrope-like compositions is determined by visual observation of the coupons.
• the azeotrope-like composition of Example 1 is effective as a solvent.
• Example 4 is repeated using the azeotrope-like composition of Example 2.
• the azeotrope-like composition of Example 2 is effective as a solvent.
• Example 4 is repeated using the azeotrope-like composition of Example 3.
• the azeotrope-like composition of Example 3 is effective as a solvent.
• a 177.5 cm 3 (six-ounce) three-piece aerosol can is used.
• the azeotrope-like composition of Example 1 is weighed into a tared aerosol can. After purging the can with tetrafluoroethane in order to displace the air within the container, a valve is mechanically crimped onto the can. Liquid chlorodifluoromethane is then added through the valve utilizing pressure burettes.
• a printed circuit board having an area of 244.85 cm 2 (37.95 square inches)and densely populated with dip sockets, resistors, and capacitors is precleaned by rinsing with isopropanol before wave soldering.
• the board is then fluxed and wave soldered using a Hollis TDL wave solder machine.
• the printed circuit board is then spray cleaned using the aerosol can having the azeotrope-like composition therein.
• the cleanliness of the board is tested visually and also using an Omega-meter which measured the ionic contamination of the board.
• the azeotrope-like composition of Example 1 is particularly useful as a solvent for spray cleaning applications.
• Example 7 is repeated except that the azeotrope-like composition of Example 2 is used.
• the azeotrope-like composition of Example 2 is particularly useful as a solvent for spray cleaning applications.
• Example 7 is repeated except that the azeotrope-like composition of Example 3 is used.
• the azeotrope-like composition of Example 3 is particularly useful as a solvent for spray cleaning applications.
• Inhibitors may be added to the present azeotrope-like compositions to inhibit decomposition of the compositions; react with undesirable decomposition products of the compositions; and/or prevent corrosion of metal surfaces.
• Any or all of the following classes of inhibitors may be employed in the invention: epoxy compounds such as propylene oxide; ethers such as 1-4-dioxane; unsaturated compounds such as 1,4-butyne diol; acetals or ketals such as dipropoxy methane; ketones such as methyl ethyl ketone; alcohols such as tertiary amyl alcohol; esters such as triphenyl phosphite; and amines such as triethyl amine.
• Other suitable inhibitors will readily occur to those skilled in the art.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
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• Oil, Petroleum & Natural Gas (AREA)
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• Life Sciences & Earth Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Detergent Compositions (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Manufacturing Of Printed Wiring (AREA)

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Publications (2)

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• 1991
  • 1991-07-10 WO PCT/US1991/004842 patent/WO1992002666A1/en active IP Right Grant
  • 1991-07-10 DE DE69122396T patent/DE69122396D1/de not_active Expired - Lifetime
  • 1991-07-10 ES ES91913860T patent/ES2091936T3/es not_active Expired - Lifetime
  • 1991-07-10 KR KR1019930700340A patent/KR930701583A/ko not_active Application Discontinuation
  • 1991-07-10 EP EP91913860A patent/EP0542796B1/en not_active Expired - Lifetime
  • 1991-07-10 AU AU82888/91A patent/AU8288891A/en not_active Abandoned
  • 1991-07-10 CA CA002087847A patent/CA2087847A1/en not_active Abandoned
  • 1991-07-10 AT AT91913860T patent/ATE143419T1/de not_active IP Right Cessation
  • 1991-07-10 JP JP91512931A patent/JPH05508880A/ja active Pending
  • 1991-07-29 MX MX9100409A patent/MX9100409A/es unknown

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