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(11) | EP 0 394 994 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Solvent composition |
| (57) The present application provides:
(1) a solvent comprising a fluorine-containing alcohol, (2) a solvent composition comprising a fluorine-containing alcohol and water. (3) a solvent composition comprising a fluorine-containing alcohol, an aliphatic alcohol and water, and (4) a solvent composition comprising a fluorine-containing alcohol and a surfactant. |
FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
[0002] Chlorofluoroethanes such as 1,1,2,2-tetrachloro-1,2-difluoroethane (R-112), 1,1,2-trichloro-1,2,2-trifluoroethane (R-113) and the like have heretofore been used as solvent or detergent. These solvents have various excellent properties: they are nonflammable and low in toxicity to organisms; they can selectively solve fat, grease, wax and the like but do not attack plastics, rubber and like high molecular weight materials. However, R-113 and some chlorofluorocarbons are recently pointed out to be responsible for the destruction of the ozone layer in the stratosphere. The destruction of ozone layer will exert an adverse influene on the whole ecosystem including mankind. Thus, the use and production of chlorofluorocarbons which may contribute to the destruction of the ozone layer are now restricted under international agreements and it is expected the use and production thereof would be totally banned.
[0003] Various compounds and materials have been proposed as solvents which may replace chlorofluoro carbons. However, they have some defects and cannot fully satisfy the requirements as practical solvent. For example, chlorine containing solvents such as 1,1,1-trichloroethane, trichloroethylene, methylene chloride and the like attack high molecular materials such as plastics and are likely to cause environmental pollution. Alcohols and hydrocarbons are low in detergency and highly inflammable.
SUMMARY OF THE INVENTION
[0004] It is the primary object of the present invention to provide new compositions which can replace the conventional chlorofluoroethanes and which have excellent properties as solvent.
[0005] Other objects and feature of the invention will become apparent from the following description.
[0006] The present invention provides a solvent composition comprising a fluorine-containing alcohol (hereinafter referred to as Composition I).
[0007] The present invention provides also a solvent composition comprising a fluorine-containing alcohol and water (hereinafer referred to as Composition II).
[0008] A detergent for water soluble flux is generally required to have following properties; it exhibits high cleansing power; it is nonflammable; it has no or little influence on the environment, etc. However, no detergent has been found or proposed which fulfills all these requirements. Thus, purified water is used for eliminating flux because it is harmless, low in cost and does not affect the ecosystem although it has some inherent defects: it cannot wash away the flux retained in narrow spaces or apertures because of its high surface tension; it cannot be dried quickly; treatment of waste water is costly, etc.
[0009] We conducted extensive research to find a novel solvent which can effectively remove water soluble flux from substrate such as electronic and electric parts, etc. and found that a fluorine-containing alcohol can be a solvent suitable to substitute water.
[0010] We continued our research further and found that compositions comprising a fluorine-containing alcohol and a suitable additive or additives exhibit excellent properties required of general solvent or detergent.
[0011] Thus, the present invention provides a solvent composition comprising a fluorine-containing alcohol, an aliphatic alcohol having 1 to 4 carbons and water (hereinafter referred to as Composition III).
[0012] The present invention further provides a solvent composition comprising a fluorine-containing alcohol and a surfactant (hereinafter referred to as Composition IV).
DETAILED DESCRIPTION OF THE INVENTION
I. Composition I
[0014] The fluorine-containing alcohols to be used in Composition I preferably have 2 or more carbon atoms in the molecule wherein at least 2 of hydrogen atoms are substituted by fluorine atoms.
[0016] In the above formulae of the fluorine-containing alcohols, a, c, e, g and i signify each an integer of 1 to 5 and b, d, f, h and j signify each an integer of 1 to 3.
[0017] Among these fluorine-containing alcohols, trifluoroethanol (hereinafter simply referred to as 3FE: boiling point = 77°C), tetrafluoropropanol (hereinafter simply referred to as 4FP: boiling point = 107°C) and pentafluoroethanol (hereinafter referred to as 5FP: boiling point = 81°C) are more preferable. 5FP is most preferable because it is nonflammable. These fluorine-containing alcohols can be used singly or in a mixture of at least two kinds.
[0018] Composition I can contain a conventional stabilizer to improve chemical stability for use under severe conditions. Examples of stabilizers are benzotriazol, 2-(2′-hydroxy-5′-methylphenyl)benzotriazol, chlorobenzotriazol and like triazols, etc. These stabilizers are usable singly or in a mixture of 2 or more kinds. Although variable with the kind of stabilizer, the amount thereof is usually about 0.1 to about 10% by weight, preferably about 0.2 to about 5% by weight based on the weight of Composition I.
II. Composition II
[0019] The fluorine-containing alcohols to be used in Composition II are the same as in Composition I. Fluorine-containing alcohols in Composition II can be used singly or at least 2 of them can be used. 3FE, 4FP and 5FP are more preferable and 5FP is most preferable also in Composition II.
[0020] Composition II comprises up to 80% by weight of water and not less than 20% by weight of at least one of fluorine-containing alcohols. Composition II preferably comprises up to 50% by weight of water and not less than 50% by weight of at least one of fluorine-containing alcohols. Composition II containing more than 50% by weight of fluorine-containing alcohol shows extremely high detergency. The cleansing power of Composition II gradually declines with the increase of water content. When the water content exceeds 80% by weight of Composition II, desired effect as detergent is greatly reduced, hence impractical.
[0021] A mixture of 4FP/water = 72.5/27.5 and a mixture of 5FP/water = 96/4 are particularly preferable because they form azeotropic compositions.
[0022] A mixture of 3FE and water does not form an azeotrope but behaves as an "azeotrope-like composition".
[0023] Stabilizers as indicated above can be incorporated into Composition II in a similar amount to improve stability thereof.
III. Composition III
[0024] The fluorine-containing alcohols to be used in Composition III are the same as those used in Composition I and can be used singly or in a mixture of at least two kinds. 3FE, 4FP and 5FP are more preferable and 5FP is most preferable.
[0025] Aliphatic alcohols to be used in Composition III are those having 1 to 4 carbon atoms such as methanol, ethanol, butanol, iso-propanol, etc.
[0026] Composition III usually comprises about 99 to about 60% by weight of the fluorine-containing alcohol, about 0.5 to about 20% by weight of the aliphatic alcohol and about 0.5 to about 20% by weight of water. Composition III preferably comprises about 91 to about 85% by weight of the fluorine-containing alcohol, about 1 to about 3% by weight of the aliphatic alcohol and about 8 to about 12% by weight of water. When the content of the aliphatic alcohol is more than 3% by weight, Composition III shows increasingly inflammability. In addition, when Composition III contains more than 3% of the aliphatic alcohol and more than 12% of water, it shows a slight tendency to separate into two liquid phases.
[0027] Stabilizers as given above can be used in Composition III in a similar amount as in Composition I.
IV. Composition IV
[0028] The fluorine-containing alcohols to be used in Composition IV are the same as those in Composition I. They may be used singly or 2 or more of them can be used in mixture.
(1) Nonionic surfactants:
[0030]
A ... Sorbitan aliphatic acid ester
wherein R represents alkyl group having 7 to 18 carbons.
B ... Clycerol aliphatic acid ester
wherein R represents alkyl group having 7 to 18 carbons.
C ... Poly(oxyethylene)glycerol aliphatic acid ester
wherein R represents alkyl group having 7 to 18 carbon atoms and m + n = 5-15.
D ... Poly(oxyethylene)alkyl ether
R-O-(CH₂CH₂O)nH
wherein R represents alkyl group having 7 to 18 carbon atoms and n = 2 to 40.
E ... Poly(oxyethylene)poly(oxypropylene)alkyl ether wherein R represents alkyl group having 7 to 18 carbon atoms and n = 1 to 20.
F ... Poly(oxyethylene)alkylphenyl ether
wheren R represents alkyl group having 8 to 9 carbon atoms and n = 2 to 30.
G ... Poly(oxyethylene)alkyl amine
wherein R represents alkyl group having 7 to 18 carbon atoms and m + n = 4-20.
H ... Poly(ethylene glycol)aliphatic acid ester
R-
-O-(CH₂CH₂O)nH
wherein R represents alkyl group having 7 to 18 carbon atoms and n = 1 to 55.
(2) Anionic surfactants:
[0031]
I ... Alkyl sulfate
wherein R represents alkyl group having 7 to 18 carbon atoms.
J ... Poly(oxyethylene)alkyl ether sulfate
wherein R represent alkyl group having 7 to 18 carbon atoms and n = 2 to 4.
K ... N-acylamino acids and salts thereof
wherein R represents alkyl group having 7 to 18 carbon atoms.
[0032] Composition IV usually comprises about 85 to about 99.5% by weight of the fluorine-containing alcohol and about 15 to about 0.5% by weight of the surfactant. Composition IV preferably comprises about 90 to about 95% by weight of the fluorine-containing alcohol and about 10 to about 5% by weight of the surfactant. When the amount of the surfactant in Composition IV is less than 0.5% by weight, the detergency of the composition is not significantly improved. Use of the surfactant in an amount more than 15% by weight does not achieve more improved cleansing power and may require an additional step for removing the surfactant itself from the article washed.
[0034] Compositions I and II of the invention selectively dissolve away water base flux from the article made of metal, plastics, rubber, etc. to be washed while hardly attacking the article itself. Composition I and II are especially useful for eliminating the flux left on electronic and electric parts after soldering step.
[0035] Compositions I and II are more volatile than water and the drying time after cleansing of articles is greatly reduced.
[0037] Compositions III and IV of the invention dissolve away and remove fat, grease, wax, paint, printing ink, etc. from the substrate made of metal, high molecular compounds such as plastics, rubber, etc. without damaging the substrate. Compositions III and IV are therefore very useful as solvent for eliminating grease and dirt from parts of electronic and electric devices, metal products, detergent for removing releasing agent from mold, etc.
[0039] Composition IV of the invention containing a surfactant is very stable and easy to maintain the highly improved cleansing properties.
Examples
Examples 1 to 5
[0041] Solvents according to the invention (Composition I and II) were tested for cleansing power against a water soluble flux.
[0042] Solvents used were as follows:
(I) 5FP
(II) 5FP/water = 94/6 (azeotrope)
(III) 4FP
(IV) 4FP/water = 72.5/27.5 (azeotrope)
(V) 3FE
[0043] To a test piece of printed circuit boad made of phenolic resin (50 mm x 50 mm) was applied a water soluble flux (trademark "solder-right TF-33B˝, product of Tamura Seisakusho, Japan) and soldering was carried out at 250°C for 5 seconds.
[0044] After test piece was cooled to room temperature and immersed in a solvent (300 ml) for 2 minutes, the amount of the flux remaining on the test piece was measured.
Comparison Examples 1 to 4
[0046] The procedure of Example 1 were repeated except that the following solvents or detergents were used in place of 5FP.
[0047] Solvents or detergents used were as follows:
(VI) Water
(VII) Methanol
(VIII) Ethanol
(IX) 1,1,1-Trichloroethane
[0049] The results shown in Table 1 establish that the solvents of the invention exhibit high cleansing power.
Examples 6 to 13 and Comparison Examples 5 to 6
[0050] The combustibility of the solvents of the invention (Composition III) and the solvents of Comparison Examples was investigated.
[0052] Solvent mixtures used were as follows:
(1) Comparison Example 5;
5FP/isopropanol (IPA) = 98/2
(2) Comparison Example 6;
5FP/ethanol (Et) = 98/2
[0053] The results are given in Table 2 below.
Table 2
| Solvent | Combustibility | |
| Ex. 6 | 5FP/IPA/Water=88/2/10 | Nonflammable |
| 7 | 5FP/IPA/Water=85/3/12 | Nonflammable |
| 8 | 5FP/IPA/Water=70/20/10 | Inflammable |
| 9 | 5FP/Et/Water =88/2/10 | Nonflammable |
| 10 | 5FP/Et/Water =85/3/12 | Nonflammable |
| 11 | 5FP/Et/Water =70/20/10 | Inflammable |
| 12 | 3FE/IPA/Water=88/2/10 | Inflammable |
| 13 | 4FP/IPA/Water=88/2/10 | Inflammable |
| Comp.Ex.5 | 5FP/IPA=98/2 | Nonflammable |
| 6 | 5FP/Et =98/2 | Nonflammable |
[0054] Further, the solvents were tested for cleansing power against water soluble flux following the procedure of Example 1 except that the fluxes (products of Tamura Seisakusho, Japan) indicated below were used.
* Flux (I) ..... trademark "F-AL-1"
* Flux (II) .... trademark "F-AL-4"
* Flux (III) ... trademark "Y-20"
* Flux (IV) .... trademark "HI-15"
[0055] The results are given in Table 3 below.
Table 3
| Residual Flux | ||||
| (I) | (II) | (III) | (IV) | |
| Ex. 6 | B | A | B | B |
| 7 | B | A | B | B |
| 8 | A | A | B | A |
| 9 | B | A | C | B |
| 10 | B | A | B | B |
| 11 | A | A | B | A |
| 12 | B | B | B | B |
| 13 | B | B | B | B |
| Comp. Ex. 5 | C | B | C | C |
| 6 | C | B | C | C |
[0056] Next, the influence of solvents of Example 6 to 13 on plastics (weight increase by swelling of the material) was inspected.
[0057] Immediately after a test piece of plastics (5 mm x 50 mm x 2 mm) was immersed and kept in a solvent at 50°C for 1 hour, the test piece was weighed to find the weight increase. The results are given in Table 4 below.
[0058] The plastics used were as follows.
(a) ..... polystyrene
(b) ..... epoxy resin
(c) ..... polypropylene
(d) ..... phenolic resin
Table 4
| Weight increase | ||||
| Example | (a) | (b) | (c) | (d) |
| 6 | A | A | A | A |
| 7 | A | A | A | A |
| 8 | A | A | A | A |
| 9 | A | A | A | A |
| 10 | A | A | A | A |
| 11 | A | A | A | A |
| 12 | A | A | A | A |
| 13 | A | A | A | A |
| * A : Increase of less than 5% | ||||
| B : Increase of 5% to 50% | ||||
| C : Increase more than 50% | ||||
Examples 14 to 25
[0059] Solvents according to the invention (Composition IV) were tested for cleansing power against a water soluble flux.
[0060] The solvents used comprise 93% by weight of 3FE, 4FP or 5FP and 7% by weight of surfactant or surfactants shown below. When the solvent contains two kinds of surfactants, they are in an equal amount.
(1) Sorbitan monolaurate
(2) Glyceryl monostearate
(3) Poly(oxyethylene)glyceryl monostearate
(4) Poly(oxyethylene)lauryl ether
(5) Poly(oxyethylene)poly(oxypropylene) cetyl ether
(6) Poly(oxyethylene)nonylphenyl ether
(7) Poly(oxyethylene)stearyl amine
(8) Poly(ethylene glycol)monostearate
(9) Sodium dodecyl sulfate
(10) Poly(oxyethylene)lauryl ether sodium sulfate
(11) Sodium N-lauroylsarcosinate
1 A solvent comprising a fluorine-containing alcohol.
2. A solvent according to claim 1 wherein the fluorine-containing alcohol has at least
2 carbon atoms in the molecule wherein at least 2 of hydrogen atoms are substituted
by fluorine atoms.
3. A solvent composition comprising a fluorine-containing alcohol and water.
4. A solvent composition according to claim 3 wherein a solvent according to claim
1 wherein the fluorine-containing alcohol has at least 2 carbon atoms in the molecule
wherein at least 2 of hydrogen atoms are substituted by fluorine atoms.
5. A solvent composition according to claim 3 which comprises up to 80% by weight
of water and not less than 20% by weight of a fluorine-containing alcohol.
6. A solvent composition according to claim 5 which comprises up to 50% by weight
of water and not less than 50% by weight of a fluorine-containing alcohol.
7. A solvent composition according to claim 6 which comprises 72.5% by weight of tetrafluoropropanol
and 27.5% by weight of water.
8. A solvent composition according to claim 6 which comprises 96% by wight of pentafluoropropanol
and 4% by weight of water.
9. A solvent composition comprising a fluorine-containing alcohol, an aliphatic alcohol
and water.
10. A solvent composition according to claim 9 which comprises about 99 to about 60%
by weight of fluorine-containing alcohol, about 0.5 to about 20% by weight of aliphatic
alcohol and about 0.5 to about 20% by weight of water.
11. A solvent composition according to claim 10 which comprises about 91 to about
85% by weight of fluorine-containing alcohol, about 1 to about 3% by weight of aliphatic
alcohol and about 8 to about 12% by weight of water.
12. A solvent composition comprising a fluorine-containing alcohol and a surfactant.
13. A solvent composition according to claim 12 which comprises about 85 to about
99.5% by weight of fluorine-containing alcohol and about 15 to about 0.5% by weight
of surfactant.
14. A solvent composition according to claim 13 which comprises about 90 to about
95% by weight of fluorine-containing alcohol and about 10 to about 5% by weight of
surfactant.