Classifications

• • 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
• • 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
• • 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
  • C11D7/504—Azeotropic mixtures containing halogenated solvents all solvents being halogenated hydrocarbons
  • C11D7/5045—Mixtures of (hydro)chlorofluorocarbons

Definitions

• a stabilized azeotrope-like composition comprising an azeotrope-like composition consisting of effective amounts of 1,1-dichloro-2,2,2-trifluoroethane and 1,1-dichloro-1-fluoroethane, such azeotrope-like composition having a boiling point of about 31°C at substantially atmospheric pressure and a stabilizer package comprising one or more of effective stabilizing amounts of nitromethane, diisopropylamine, 1,2-butylene oxide and/or 4-methoxyphenol.
• the stabilizer package may also comprise effective stabilizing amounts of 1,2-propylene oxide and nitromethane with or without one or more of diisopropylamine, 1,2-butylene oxide and/or 4-methoxyphenol.
• HCFC-123 1,1-dichloro-2,2,2-trifluoroethane
• HCFC-141b 1,1-dichloro-1-fluoroethane
• effective stabilizing amounts at least some of one or more of nitromethane, diisopropylamine, 1,2-butylene oxide and/or 4-methoxyphenol. Also, by effective stabilizing amounts is meant at least some of 1,2-propylene oxide and nitromethane with or without one or more of diisopropylamine, 1,2-butylene oxide and/or 4-methoxyphenol.
• the effective stabilizing amounts of the disclosed compounds When the effective stabilizing amounts of the disclosed compounds are combined with the azeotrope-like composition of 1,1-dichloro-2,2,2-trifluoroethane (CHCl2CF3) and 1,1-dichloro-1-fluoroethane (CCl2FCH3), they allow such azeotrope-like composition to be used and stored commercially, i.e., provide commercially acceptable appearance, corrosivity and resistance to loss of integrity of the azeotrope-like composition.
• CHCl2CF3 1,1-dichloro-2,2,2-trifluoroethane
• CCl2FCH3 1,1-dichloro-1-fluoroethane
• HCFC-123 may contain minor amounts of 1,2-dichloro-1,1,2-trifluoroethane, e.g., as much as about 20.0 weight percent 1,2-dichloro-1,1,2-trifluoroethane (HCFC-123a) which mixture is intended to be covered by the language 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) as well as the inclusion of minor amounts of other materials which do not significantly alter the azeotrope-like character of the cleaning solvent compositions.
• HCFC-123a 20.0 weight percent 1,2-dichloro-1,1,2-trifluoroethane
• HCFC-123 1,1-dichloro-2,2,2-trifluoroethane
• the stabilized compositions of the present invention may comprise admixtures of effective amounts of 1,1-dichloro-2,2,2-trifluoroethane and 1,1-dichloro-1-fluoroethane, which compositions form azeotrope-like compositions which may contain one or more of about 0.1 to 0.8 weight percent of nitromethane, about 0.05 to 0.4 weight percent 1,2-propylene oxide, about 0.025 to 0.2 weight percent diisopropylamine and about 0.002 to 0.016 weight percent 4-methoxyphenol, said stabilizer weight percentages are based on the weight of the azeotrope-like compositions.
• the present azeotrope-like compositions comprise admixtures of 1,1-dichloro-2,2,2-trifluoroethane and 1,1-dichloro-1-fluoroethane, more specifically, the present compositions comprise mixtures of about 1-99 weight percent 1,1-dichloro-2,2,2-trifluoroethane and about 99-1 weight percent 1,1-dichloro-1-fluoroethane.
• the present azeotrope-like compositions may also comprise admixtures of about 20-80 weight percent 1,1-dichloro-2,2,2-trifluoroethane and about 80-20 weight percent 1,1-dichloro-1-fluoroethane which boil at about 31°C, at substantially atmospheric pressure.
• azeotrope-like compositions of the instant invention which contain a minimum of about weight percent 1,1-dichloro-2,2,2-trifluoroethane are nonflammable, as determined by a flammability test similar to ASTM E918.
• a preferred azeotrope-like composition of the instant invention has the following composition: about 65 weight percent 1,1-dichloro-2,2,2-trifluoroethane and about 35 weight percent 1,1-dichloro-1-fluoroethane.
• the azeotrope-like composition boils at about 31°C, at substantially atmospheric pressure.
• azeotrope-like compositions are effective solvents for cleaning electronic circuit boards.
• Such solvent compositions are characterized by desirable properties of relatively low boiling points, non-flammability, relatively low toxicity and high solvency for flux and flux residues.
• the components also permit easy recovery and reuse without loss of their desirable characteristics because of their azeotrope-like natures and relatively low boiling points.
• the circuit board to be cleaned is first passed through a sump which contains boiling solvent, for removal of bulk rosin, including thermally degraded rosin.
• the organic solvent is in contact with a heat source for a prolonged time.
• the circuit board is passed through a sump which contains freshly distilled solvent and finally through solvent vapor over a boiling sump, which provides a final rinse with a clean solvent which condenses on the circuit board.
• the organic solvent is subjected to constant heating either in maintaining boiling sumps or in vaporizing the solvent to provide freshly distilled solvent or vapor to condense on the circuit board for the final rinse. It is, therefore, highly desirable to minimize any change in the solvent system which can adversely affect the cleaning process or degrade the integrity of the solvent. As mentioned earlier, such changes may be due to oxidation, polymerization or interaction between the solvent system components.
• one such interaction which should be minimized is the interaction between the hydrochlorofluorocarbons and metals, at elevated temperatures, which may generate acidic by-products and chloride ions.
• Reactive metals such as zinc and aluminum as well as certain aluminum alloys, which are often used as materials of circuit board construction, are particularly susceptible to such interaction. It has been found that nitromethane may be incorporated in the present solvent system in concentrations of about 0.1 to 0.8 weight percent and effectively retard this type of attack and, in addition, prevent the formation of gel.
• the stabilizer package comprising diisopropylamine, in a concentration of about 0.025 to 0.2 weight percent, 4-methoxyphenol, in a concentration of about 0.002 to 0.016 weight percent, 1,2-propylene oxide, in a concentration of about 0.05 to 0.4 weight percent, and nitromethane, in a concentration of about 0.05 to 0.8 weight percent, enhances the stability of the present solvent system. All weight percentages are based on the weight of the of the 1,1-dichloro-2,2,2-trifluoroethane and 1,1-dichloro-1-fluoroethane azeotrope-like composition.
• the stabilizers when used together in the present solvent system (4-methoxyphenol, 1,2-propylene oxide, diisopropylamine and nitromethane) appear to enhance the stability of the solvent system.
• the ranges of acceptable performance for stabilizer concentrations when used together is the same as disclosed herein for when they are used separately. It should be noted that stabilizer concentrations higher than those specified can be employed; under normal circumstances, however, higher stabilizer concentrations do not generally provide additional inhibition advantage.
• inhibitor-stabilizer systems which provide storage and use stability to the aforedescribed azeotrope-like compositions are: Inhibitor(s) Weight Percentage(s) Nitromethane 0.2 Diisopropylamine 0.05 1,2-Butylene oxide 0.05 4-Methoxyphenol 0.004 Nitromethane + 1,2-propylene oxide 0.2 + 0.05 Nitromethane + 1,2-butylene oxide 0.2 + 0.05 Nitromethane + 1,2-propylene oxide + diisopropylamine 0.2 + 0.05 + 0.05 Nitromethane + 1,2-butylene oxide + diisopropylamine 0.2 + 0.05 + 0.05 Nitromethane + 1,2-butylene oxide + diisopropylamine 0.2 + 0.05 + 0.05 Nitromethane + 1,2-propylene oxide + 1,2-butylene oxide 0.2 + 0.05 + 0.05 Nitromethane + 1,2-propylene oxide + 4-methoxyphenol 0.2 + 0.05 + 0.004
• the preferred stabilized, constant-boiling, azeotrope-like composition of the present invention contains about 65 weight percent of 1,1-dichloro-2,2,2-trifluoroethane, about 35 weight percent 1,1-dichloro-1-fluoroethane, about 0.1 to 0.8 weight percent of nitromethane, about 0.05 to 0.4 weight percent 1,2-propylene oxide, and about 0.025 to 0.2 weight percent percent diisopropylamine and about 0.002 to 0.016 weight percent 4-methoxyphenol.
• a more preferred, stabilized, azeotrope-like composition of the present invention contains about 65 weight percent 1,1-dichloro-2,2,2-trifluoroethane, and about 35 weight percent 1,1-dichloro-1-fluoroethane, about 0.2 weight percent nitromethane, about 0.05 weight percent 1,2-propylene oxide, about 0.05 weight percent diisopropylamine and about 0.004 weight percent 4-methoxyphenol.
• the present invention thus provides stabilized, azeotrope-like compositions of 1,1-dichloro-2,2,2-trifluoroethane and 1,1-dichlorolfluoroethane, which can be stored for long periods periods of time, which will undergo little or no change during either prolonged storage or commercial use and which minimize both aluminum corrosion and gel formation.
• the methods of combining the inhibitors with the azeotrope-like compositions of this invention are well-known in the art. They can be prepared by any convenient method including mixing or combining the desired component amounts in suitable containers. A preferred method is to weigh the desired component amounts and thereafter combine them in an appropriate container.
• the aforestated stabilized, azeotrope-like compositions have low ozone depletion potentials and are expected to decompose almost completely prior to reaching the stratosphere.
• the stabilized, azeotrope-like compositions of the present invention permit easy recovery and reuse of the solvent from vapor defluxing and degreasing operations because of their azeotrope-like natures.
• the azeotrope-like mixture of this invention can be used in cleaning processes such as described in U.S. Patent No. 3,881,949, which is incorporated herein by deference.
• Comparative seven day stability tests of solvent system combinations of about 65 weight percent 1,1-dichloro-2,2,2-trifluoroethane and about 35 weight percent 1,1-dichloro-1-fluoroethane with various inhibitor combinations were carried out by refluxing 150 ml of the solvent combination in a series of 500 ml Pyrex® flasks using 90 percent, at 25°C, water-saturated solvents. The flasks were connected to water-cooled condensers, on top of which were affixed Drierite® desiccant tubes to exclude atmospheric moisture from the test systems. Additionally, stainless steel (SS-304) specimens were located at the refluxing solvent vapor/air interfaces in the condensers and coupled stainless steel (SS-304)/aluminum alloy (AL-7075) specimens were located in the boiling liquids.
• SS-304 stainless steel
• the 1,1-dichloro-1-fluoroethane used in these tests contained about 500 parts per million by weight of vinylidene chloride, an impurity normally found in the crude product; however, no vinylidene chloride was used in test number 1 below.
• the solvent inhibitor systems tested are described in the Table.
• Chloride ion concentration was measured at the end of the test by extracting the solvent with an equal volume of deionized water and analyzing the water for chloride ion concentration.
• the original, uninhibited, solvent contained less than 0.2 ppm chloride ion.
• Chloride ion increase generally represents loss of solvent system component stability. Stability loss is generally accompanied by increased acidity.
• Corrosion rates were measured by rubbing the metal surfaces with ink and pencil erasers, brushing the surfaces, rinsing the specimens sequentially with 1,1,2-trichlorotrifluoroethane, deionized water and acetone, drying for 24 hours over Drierite® desiccant and weighing the sample to 0.0001 gram, Metal specimen weight loss is expressed in mils/year. An aluminum (Al-7075) corrosion rate of 4 mils/year is considered acceptable. 4.

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• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Metallurgy (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
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• Manufacturing Of Printed Wiring (AREA)

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Cited By (7)

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• 1990
  • 1990-10-03 CA CA002026865A patent/CA2026865A1/fr not_active Abandoned
  • 1990-10-04 EP EP90310884A patent/EP0421790A2/fr not_active Withdrawn
  • 1990-10-05 BR BR909005006A patent/BR9005006A/pt unknown
  • 1990-10-05 KR KR1019900015942A patent/KR910008169A/ko not_active Application Discontinuation
  • 1990-10-05 AU AU63871/90A patent/AU6387190A/en not_active Abandoned
  • 1990-10-05 JP JP2266543A patent/JPH03237199A/ja active Pending
  • 1990-10-05 CN CN90109210A patent/CN1051203A/zh active Pending

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