WO2003025109A1

WO2003025109A1 - Cleaning or drying compositions based on n-perfluorobutyl-ethylene and hfc 365mfc

Info

Publication number: WO2003025109A1
Application number: PCT/FR2002/003149
Authority: WO
Inventors: Pascal Michaud; Jean-Jacques Martin
Original assignee: Atofina
Priority date: 2001-09-17
Filing date: 2002-09-16
Publication date: 2003-03-27
Also published as: FR2829773A1

Abstract

The invention proposes azeotropic or quasi-azeotropic compositions based on HFC 365mfc (1,1,1,3,3-pentafluorobutane) and n-perfluorobutyl-ethylene for replacing compositions based on CFC or HCFC for cleaning and drying of solid surfaces (in particular flux removal).

Description

CLEANING OR DRYING COMPOSITIONS BASED ON N-PERFLUOROBUTYL-ETHYLENE AND HFC 365mfc

DESCRIPTION

The present invention relates to the field of fluorinated hydrocarbons and more particularly relates to new compositions which can be used for cleaning or drying solid surfaces.

The l, l, 2-trichloro-l, 2,2-trifluoroethane (known in the art under the designation FI 13) has been widely used in the industry for cleaning and degreasing a wide variety of solid surfaces (metal parts, glasses, plastics, composites), for which an absence - or at least a residual content as low as possible - of impurities, especially of organic nature, is required. The F 113 was particularly suitable for this use because of its non-aggressive nature with regard to the materials used. This product has been used in particular in the manufacture of printed circuits, to remove residues of substances used to improve the quality of the solder (designated by the term of solder flux). This elimination operation is designated in the art by the term "defluxing".

Mention may also be made of the applications of the FI 13 to the degreasing of heavy metal parts and to the cleaning of high quality and high precision mechanical parts such as, for example, gyroscopes and military, aerospace or medical equipment. In its various applications, FI 13 is most often combined with other organic solvents (for example methanol), in order to improve its cleaning capacity. It is therefore preferable to use azeotropic or quasi-azeotropic mixtures. By quasi-azeotropic mixture is meant in the sense of the present invention a mixture of generally miscible chemical compounds which, under certain particular conditions of proportions, temperature and pressure, boils at substantially constant temperature while retaining substantially the same composition. When heated to reflux, such a quasi-azeotropic mixture is in equilibrium with a vapor phase whose composition is substantially the same as that of the liquid phase. Such an azeotropic or quasi-azeotropic behavior is desirable to ensure satisfactory operation of the machines in which the abovementioned cleaning operations are carried out, and in particular to ensure recycling by distillation of the cleaning fluid.

The FI 13 is also used in fields, in particular in optics, for which it is required to have surfaces free of water, that is to say surfaces where water is present only at the state of traces undetectable by the measurement method (Karl Fisher method). FI 13 is used for this purpose in drying (or dewetting) operations of said surfaces, in combination with hydrophobic surfactants. However, the use of compositions based on FI 13 is now prohibited, since FI 13 is one of the chlorofluorocarbons (CFCs) suspected of attacking or degrading stratospheric ozone.

In these various applications, the FI 13 can be replaced by 1,1-dichloro-1-fluoroethane (known under the designation F141b), but the use of this substitute is already regulated because, although weak, its destructive effect vis -with respect to ozone is not zero.

Application EP 894851 describes a quasi-azeotropic mixture consisting of 75 to 95% by weight of 1,1,1,3,3-pentafluorobutane, from 1 to 15% of dichloromethane, and from 1 to 10% of methanol, which can be used as a substitute of FI 13. 1,1,1,3,3-Pentafluorobutane, also known in the art under the name of F365mfc, is devoid of any destructive effect with respect to ozone.

Also known from patent application EP 974642, and for the same purpose, azeotropic or quasi-azeotropic compositions comprising from 75 to 99% by weight of 1,1,1,3,3-pentafluorobutane and from 1 to 25% of 1, 1,1,2,3,4,4,5,5,5-decafluoropentane.

Finally, application EP 1046703 discloses azeotropic or quasi-azeotropic compositions comprising from 45 to 65% of 1,1,1,3,3-pentafluorobutane, from 30 to 50% of dichloromethane and small amounts of methanol and of 1, 1,1,2,3,4,4,5,5,5- decafluoropentane.

The object of the invention is to propose other compositions which can be used as a substitute for FI 13 or F 141b, and which do not have a destructive effect with respect to ozone.

To contribute to solving this problem, the present invention therefore relates to azeotropic or quasi-azeotropic compositions comprising from 1 to 99% of n-perfluorobutyl-ethylene, preferably from 1 to 80%, and from 1 to 99% of 1, 1,1,3,3- pentafluorobutane, preferably from 20 to 99%. Unless otherwise indicated, the percentages used in the present text to indicate the content of the compositions according to the invention are percentages by weight. The n-perfluorobutyl-ethylene is a compound completely devoid of destructive effect with respect to ozone. When such compositions are heated to reflux, the liquid phase is in equilibrium with the vapor phase with a distribution of the components substantially identical between the 2 phases.

According to a first preferred embodiment of the invention, the azeotropic or quasi-azeotropic compositions according to the invention consist of 1 to 50% of n-perfluorobutyl-ethylene, and of 50 to 99% by weight of 1.1.1 , 3,3-pentafluorobutane.

According to a second preferred embodiment, the invention relates to azeotropic or quasi-azeotropic compositions comprising:

- from 20 to 80% of 1,1,1,3,3-ρentafluorobutane, preferably from 30 to 70%,

- from 1 to 10% of n-perfluorobutyl-ethylene, preferably from 5 to 10%,

- from 10 to 70% of dichloromethane, preferably from 20 to 60%. In this area, there is an azeotrope with a boiling point of 34 ° C at normal atmospheric pressure (101,300 Pa).

According to a third preferred embodiment, the subject of the invention is azeotropic or almost azeotropic compositions comprising:

- from 80 to 98% of 1,1,1,3,3-ρentafluorobutane, preferably from 85 to 97%,

- from 1 to 10% of n-perfluorobutyl-ethylene, preferably from 1 to 8%,

- from 1 to 10% of methanol, preferably from 2 to 7%.

In this area, there is an azeotrope with a boiling point of 36.8 ° C at normal atmospheric pressure (101,300 Pa).

The compositions according to the invention make it possible to obtain very good results for the cleaning and degreasing of solid surfaces, as well as in the operations of drying and dewetting of surfaces. In addition, these compositions do not exhibit a flash point under the standard determination conditions (ASTM D 3828 standard) and therefore make it possible to work in complete safety.

The compositions according to the invention can be easily prepared by simple mixing of the constituents. N-perfluorobutyl-ethylene is commercially available; 365mfc can be prepared by at least one of the following methods:

Zh. Org. Khim. 1988, 1558;

J.A.C.S. 67, 1195 (1945).

As in the known cleaning compositions based on FI 13 or F141b, the cleaning compositions based on 365 mfc and n-perflurobutyl-ethylene according to the invention can, if desired, be protected against chemical attack resulting from their contact with water (hydrolysis), with light metals (constituting the solid surfaces to be cleaned), and / or against free radical attacks likely to occur in the cleaning processes, by adding a usual stabilizer such as, for example for example, nitroalkanes (especially nitromethane, nitroethane, nitropropane), acetals (dimethoxymethane) and ethers (1,4-dioxane, 1,3-dioxolane). The proportion of stabilizer can range from 0.01 to 5% relative to the total weight of the composition.

As stabilizer, it is preferred to use dimethoxymethane, the boiling point (40 ° C) of which is close to that of the azeotropic compositions according to the invention; therefore, this stabilizer perfectly follows the evaporation and condensation cycle of the solvent, which is particularly advantageous in cleaning applications.

The compositions according to the invention can be used in the same applications and be used according to the same methods as the previous compositions based on FI 13 or F141b. They are therefore particularly suitable for use for cleaning and degreasing solid surfaces, preferably for defluxing printed circuits, as well as for drying operations on solid surfaces. As regards the latter use, it is preferable to add to the composition according to the invention a hydrophobic soluble surfactant, in order to further improve the elimination of water from the surfaces to be treated, until reaching an elimination of 100 %.

Among the hydrophobic soluble surfactants, the diamides of formula: R ¹ -CO-NR- (CH ₂ ) n-NH-CO-R ¹ (I) in which R ¹ is an alkyl radical comprising from 14 to 22 are preferred carbon atoms, preferably from 16 to 20 carbon atoms, and n is an integer inclusive between 1 and 5, preferably equal to 3.

The added amount of this surfactant is generally 0.05 to 8%.

According to another embodiment, when the use of the compositions according to the invention relates to the operations of drying surfaces, is added to these, in addition to the surfactant, from 0.5 to 10%, preferably from 1 to 5%, as co-solvent, of a polyfluorinated alcohol of formula:

Rf- (CH ₂ ) „- OH (II) in which n is equal to 1 or 2 and Rf represents a linear perfluoroalkyl radical containing from 2 to 8 carbon atoms.

The surfactant used in this case is advantageously a canonical surfactant which is obtained by reacting, in a ^1st step, a mono- or di-alkylphosphoric acid of general formula:

(R ² O) p (HO) ₂ -pPO ₂ H (III) in which p is a number ranging from 1 to 2 and R ² denotes an alkyl radical, linear or branched, containing from 1 to 18 carbon atoms; with a fluorinated amine of general formula:

R _F - X-NR3R4 (IV) in which:

- R _F represents a linear perfluoroalkyl radical containing from 2 to 20 carbon atoms,

- X represents a divalent bridge, and

- the symbols R ³ and R ⁴ , identical or different, each represent a hydrogen atom or an alkyl or hydroxyalkyl radical containing from 1 to 4 carbon atoms; then by reacting, in a 2 ^nd step, the product thus obtained with a quaternary ammonium chloride of formula:

R ' ₂ N + R " ₂ Cl- (V)

in which R and R ", which are identical or different, each represent a hydrogen atom or an alkyl or hydroxyalkyl radical containing from 1 to 4 carbon atoms. The surfactant described above is generally added to the compositions according to the invention at a content of between 0.01 and 0.5% by weight, preferably between 0.4 and 0.2%.

The preparation of the polyfluorinated alcohol of formula (II) and that of the cationic surfactant are also described in application EP 863194, the content of which is incorporated by reference, in the present application.

As regards the methods of implementation of the compositions according to the invention, mention may be made in particular of implementation in devices suitable for cleaning and / or drying surfaces, as well as by aerosol.

Concerning the use by aerosol, the compositions according to the invention can be packaged with, as propellant, 134a (or 227e of formula CF ₃ CHF-CF ₃ ), and their mixture with 152a and or DME ( Dimethylether) to offer additional cleaning possibilities, especially at room temperature. The compositions according to the invention thus conditioned do not have a flame length, according to standard 609F of the European Aerosol Federation (Brussels, Belgium) (Determination of the ignition distance of a spray or a jet emitted at from an aerosol container).

The compositions according to the invention can also be used as an agent for expanding polyurethane foams, as an agent for dry cleaning of textiles, and as a refrigerant.

The following examples illustrate the invention without limiting it.

EXAMPLE 1: quasi-azeotropic nature of the binary 365mfc / n-perfluorobutyl-ethylene: 98/2%

A small solid surface cleaning machine with a capacity of 5 liters is used. This machine comprises 2 tanks (a tank serving as a boiler and a rinsing tank, the overflow of which overflows into the boiler), and a coil ensuring the condensation of the vapors coming from the boiler, the condensates thus obtained supplying the rinsing tank.

2 1 of a composition consisting of 98% of 365mfc and 2% of n-perfluorobutylethylene are introduced into the boiler, and 3 1 of the same composition is introduced into the rinsing tank.

The composition in the boiler is brought to a boil.

After 7 hours of operation, the liquid phase is sampled in the boiler, and the condensed vapor phase is sampled in the condensation chute.

These fractions are analyzed by gas chromatography.

The results are collated in the table below.

These results show the near-azeotropy of the mixture and its ability to be used in a machine for cleaning solid surfaces.

EXAMPLE 2: quasi-azeotropic nature of the binary 365mfc / n-perfluorobutyl-ethylene: 2/98%

Example 1 is repeated with a composition consisting of 2% 365mfc and 98% n-perfluorobutyl-ethylene.

The results obtained are shown in the table below:

EXAMPLE 3: 365mfc azeotrope / n-perfluorobutyl-ethylene / dic oromethane a) Demonstration of the azeotrope:

100 g of 365mfc, 50 g of n-perfluorobutylethylene, and 100 g of dichloromethane are introduced into the distiller of a distillation column (30 trays). The mixture is then heated at reflux for one hour to bring the system to equilibrium.

When a temperature plateau is observed, a fraction of about 20 g is collected. This fraction is analyzed by gas chromatography.

Examination of the results recorded in the table below indicates the presence of an azeotropic composition.

b) Verification of the azeotropic composition:

200 g of a mixture comprising 92.9% of 365 mfc, 1.9% of n-perfluorobutyl-ethylene and 5.2% of methanol are introduced into the boiler of a distillation column (30 trays). The mixture is then heated at reflux for one hour to bring the system to equilibrium.

A fraction of about 20 g is withdrawn, which is analyzed by gas chromatography.

Examination of the results, recorded in the following table, indicates the presence of a ternary azeotrope, since the fraction collected has the same composition as the initial mixture. It is a positive azeotrope since its boiling point at atmospheric pressure is lower than that of each of the pure products, i.e. 40 ° C for 365mfc, 59 ° C for n-perfluorobutyl-ethylene and 65 ° C for methanol.

EXAMPLE 5: Cleaning of welding flux

The following test is carried out on five test circuits conforming to the IPC-B-25 standard described in the manual of test methods of the IPC (Instimte for Interconnecting and Packaging Electronic Circuits; Lincolnwood, IL, USA). These circuits are coated with rosin-based solder flux (product marketed by ALPHAMETAL under the name flux R8F) and annealed in an oven at 220 ° C for 30 seconds.

To remove the rosin thus annealed, these circuits are cleaned using the azeotropic composition of Example 4, in a small ultrasonic machine for 3 minutes by immersion in the liquid phase and 3 minutes in the vapor phase.

The cleaning is evaluated according to the standardized procedure IPC 2.3.26 (also described in the manual cited above) using a precision conductivity meter. The value obtained, 2.1 μg / cm ² eq.NaCl, is lower than the ionic impurity threshold tolerated by the profession (2.5 μg / cm ² eq.NaCl).

EXAMPLE 6 Surface drying

250 ml of a drying composition comprising 99.8% of the composition described in Example 3 are prepared, to which 0.2% of oleylamido propylene amide dioleyl (compound of formula (I), in which R is an alkyl radical comprising on average 18 carbon atoms, and n is 3).

A 5x3 cm stainless steel grid is soaked in water for a few seconds.

The water retention capacity of this grid is measured by soaking the grid in absolute ethyl alcohol, then assaying by the Karl Fisher method implemented with this alcoholic solution.

This grid is then immersed for 30 seconds in the drying composition thus prepared, with manual stirring. The grid is removed from this composition, and the residual water is assayed using the Karl Fischer method, as described above.

The elimination rate (expressed as a percentage) is the amount of residual water after drying divided by the water retention capacity of the grid (corrected for the water content of the absolute ethyl alcohol used).

A water removal rate of 100% is measured.

Claims

1. Azeotropic or quasi-azeotropic compositions comprising from 1 to 99% of n-perfluorobutyl-ethylene, preferably from 1 to 80%, and from 1 to 99% of 1,1,1,3,3-pentafluorobutane, preferably from 20 to 99%.

2. Azeotropic or quasi-azeotropic compositions according to claim 1, characterized in that they consist of 1 to 50% of n-perfluorobutyl-ethylene, and of 50 to 99% by weight of 1,1,1,3,3 -pentafluorobutane.

3. Azeotropic or quasi-azeotropic compositions according to claim 1, characterized in that they comprise:

- from 20 to 80% of 1,1,1,3,3-pentafluorobutane, preferably from 30 to 70%,

- from 1 to 10% of n-perfluorobutyl-ethylene, preferably from 5 to 10%,

- from 10 to 70% of dichloromethane, preferably from 20 to 60%.

4. Composition according to claim 3 in the form of an azeotrope whose boiling point is 34 ° C at normal atmospheric pressure.

5. Azeotropic or quasi-azeotropic compositions according to claim 1, characterized in that they comprise:

- from 80 to 98% of 1,1,1,3,3-pentafluorobutane, preferably from 85 to 97%,

- from 1 to 10% of n-perfluorobutyl-ethylene, preferably from 1 to 8%,

- from 1 to 10% of methanol, preferably from 2 to 7%.

6. Composition according to claim 5 in the form of an azeotrope whose boiling point is 36.8 ° C at normal atmospheric pressure.

7. Composition according to one of claims 1 to 6 further comprising a stabilizer, preferably dimethoxymethane.

8. Use of the compositions according to one of claims 1 to 7 for cleaning and degreasing solid surfaces, preferably for defluxing printed circuits.

9. Use of the compositions according to one of claims 1 to 7 for drying operations on solid surfaces.

10. Use according to claim 9, characterized in that a soluble hydrophobic surfactant is added to the composition.

11. Use according to claim 10, characterized in that 0.05 to 8% is added as surfactant of a diamide of formula:

R'-CO-NR ^ CH ^ n-NH-CO-R ¹ (I) in which R ¹ is an alkyl radical comprising from 14 to 22 carbon atoms, preferably from 16 to 20 carbon atoms, and n is an integer inclusive between 1 and 5, preferably equal to 3.

12. Use according to claim 10, characterized in that a polyfluorinated alcohol of formula:

Rf- (CH ₂ ) „- OH (H) in which n is equal to 1 or 2 and Rf represents a linear perfluoroalkyl radical containing from 2 to 8 carbon atoms.

13. Use according to claim 12, characterized in that one adds, as surfactant, from 0.01 to 0.5%, preferably from 0.4 to 0.2%, of a cationic compound which is obtained by reacting, in a ^first step, a mono- or di-alkylphosphoric acid of general formula:

(R ² O) p (HO) 2- _p PO ₂ H (III) in which p is a number ranging from 1 to 2 and R ² denotes; an alkyl radical, linear or branched, containing from 1 to 18 carbon atoms; with a fluorinated amine of general formula:

R _F - X-NR3R4 (IN) in which:

- X represents a divalent bridge, and

R ' ₂ N ⁺ R " ₂ Cl- (V)

in which R 'and R ", which are identical or different, each represent a hydrogen atom or an alkyl or hydroxyalkyl radical containing from 1 to 4 carbon atoms.