Patent US3957531A successfully refreshed from Google Patents.
US3957531A
Expired / Lapsed
US
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Two tank cleaning process using a contaminated cleaning mixture capable of forming an azeotrope
Assignee: Imperial Chemical Industries Ltd
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Filing: 1975-03-14
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Granted: 1976-05-18
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Expires: 1995-03-14
Abstract
Abstract Contaminated articles, especially printed circuit boards, are cleaned by immersing them in the sump compartment of a cleaning tank containing a boiling mixture of a halogenated hydrocarbon solvent, especially fluorochlorohydrocarbons containing two or three carbon atoms, having a high concentration of an organic solvent, especially isopropyl alcohol, followed by rinsing them in another boiling mixture containing a lower concentration of the organic solvent but at least equal to the organic solvent concentration of the azeotrope.
Inventors
- 👤 James William Tipping
- 👤 Bernard Patrick Whim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:31
CPC Classifications
C; C11; C11D; C11D7/00; C11D7/50; C11D7/5036; C11D7/5068; C11D7/5077; C11D7/5081; B; B01; B01D; B01D3/00; B01D3/34; B01D3/36; B08; B08B; B08B3/00; B08B3/04; B08B3/08; B08B3/10; C23; C23G; C23G5/00; C23G5/02; C23G5/028; C23G5/02809; C23G5/02812; C23G5/02816; C23G5/02819; H; H05; H05K; H05K3/00; H05K3/22; H05K3/26; H05K2203/00; H05K2203/07; H05K2203/0779; H05K2203/0783; H05K2203/08; H05K2203/088; H05K2203/15; H05K2203/1518
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
125 words
A method of cleaning a contaminated article which comprises contacting the article with a first contaminated liquid mixture which is heated to at least 30° C., removing contamination from the article and accumulating the removed contamination in the first liquid mixture, said first liquid mixture containing a fluorinated hydrocarbon solvent and an organic auxiliary solvent which together can form an azeotrope and wherein the concentration of the auxiliary solvent in the mixture is greater than that of the azeotrope itself, and subsequently rinsing the article with a second liquid mixture containing the fluorinated hydrocarbon solvent and a proportion of the auxiliary solvent which is lower than that contained in the first liquid mixture but at least equal to the auxiliary solvent concentration of the azeotrope.
Claim 2
Independent Claim
125 words
A method of cleaning a contaminated article which comprises contacting the article with a first contaminated liquid mixture which is heated to at least 30° C., removing contamination from the article and accumulating the removed contamination in the first liquid mixture, said first liquid mixture containing a fluorinated hydrocarbon solvent and an organic auxiliary solvent which together can form an azeotrope and wherein the concentration of the auxiliary solvent in the mixture is greater than that of the azeotrope itself, and subsequently rinsing the article with a second liquid mixture containing the fluorinated hydrocarbon solvent and a proportion of the auxiliary solvent which is lower than that contained in the first liquid mixture but at least equal to the auxiliary solvent concentration of the azeotrope.
Claim 3
Dependent Claim
30 words
A method as claimed in claim 1 in which there is introduced, continuously or intermittently from an external source, a supply of the fluorinated hydrocarbon solvent and the auxiliary solvent.
Claim 4
Dependent Claim
35 words
A method as claimed in claim 2 in which the supply of solvents introduced has a proportion of the auxiliary solvent from that of the azeotrope itself up to that in the second liquid mixture.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 3 in which the supply of solvents introduced has a proportion corresponding substantially to the azeotrope itself.
Claim 6
Dependent Claim
28 words
A method as claimed in claim 2 in which the supply of solvents introduced consists essentially of 97.1% by weight of 1,1,2-trichloro-1,2,2-trifluoroethane and 2.9% by weight of isopropanol.
Claim 7
Dependent Claim
52 words
A method as claimed in claim 1 which comprises immersing a contaminated article in said first heated liquid mixture, said mixture being contained in a sump compartment, and subsequently passing the article into the second liquid mixture in a rinsing compartment, the first and second liquid mixtures having a common vapour zone.
Claim 8
Dependent Claim
16 words
A method as claimed in claim 6 in which the second liquid mixture is also heated.
Claim 9
Dependent Claim
30 words
A method as claimed in claim 6 in which there is introduced a supply of the fluorinated hydrocarbon solvent and the auxiliary solvent, continuously or intermittently, into the sump compartment.
Claim 10
Dependent Claim
31 words
A method as claimed in claim 6 in which at least part of the liquid obtained by condensation of vapours from the common vapour zone is returned to the rinsing compartment.
Claim 11
Dependent Claim
20 words
A method as claimed in claim 6 in which liquid mixture overflows from said rinsing compartment to said sump compartment.
Claim 12
Dependent Claim
17 words
A method as claimed in claim 6 in which there is employed a plurality of rinsing compartments.
Claim 13
Dependent Claim
14 words
A method as claimed in claim 6 in which the fluorinated hydrocarbon is 1,1,2-trichloro-1,2,2-trifluoroethane.
Claim 14
Dependent Claim
15 words
A method as claimed in claim 6 in which the auxiliary solvent is ethyl alcohol.
Claim 15
Dependent Claim
15 words
A method as claimed in claim 6 in which the auxiliary solvent is isopropyl alcohol.
Claim 16
Dependent Claim
41 words
A method as claimed in claim 1 in which the first liquid mixture contains at least five parts by weight of the auxiliary solvent per hundred parts by weight of the total mixture above the proportion corresponding to the azeotrope itself.
Claim 17
Dependent Claim
41 words
A method as claimed in claim 15 in which the first liquid mixture contains at least ten parts by weight of the auxiliary solvent per hundred parts by weight of the total mixture above the proportion corresponding to the azeotrope itself.
Claim 18
Dependent Claim
16 words
A method as claimed in claim 1 in which the fluorinated hydrocarbon solvent is a fluorochlorohydrocarbon.
Claim 19
Dependent Claim
17 words
A method as claimed in claim 17 in which the fluorochlorohydrocarbon contains 2 or 3 carbon atoms.
Claim 20
Dependent Claim
13 words
A method as claimed in claim 18 in which the fluorochlorohydrocarbon is 1,1,2-trichloro-1,2,2-trifluoroethane.
Claim 21
Dependent Claim
21 words
A method as claimed in claim 1 in which the auxiliary solvent is an alcohol containing one to four carbon atoms.
Claim 22
Dependent Claim
14 words
A method as claimed in claim 20 in which the alcohol is ethyl alcohol.
Claim 23
Dependent Claim
25 words
A method as claimed in claim 21 in which the concentration of ethyl alcohol in the first liquid mixture is 25% to 30% by weight.
Claim 24
Dependent Claim
25 words
A method as claimed in claim 22 in which the concentration of ethyl alcohol in the second liquid mixture is 5% to 8% by weight.
Claim 25
Dependent Claim
14 words
A method as claimed in claim 20 in which the alcohol is methyl alcohol.
Claim 26
Dependent Claim
25 words
A method as claimed in claim 24 in which the concentration of methyl alcohol in the first liquid mixture is 17% to 22% by weight.
Claim 27
Dependent Claim
25 words
A method as claimed in claim 25 in which the concentration of methyl alcohol in the second liquid mixture is 8% to 10% by weight.
Claim 28
Dependent Claim
13 words
A method as claimed in claim 20 in which the alcohol is tert-butanol.
Claim 29
Dependent Claim
14 words
A method as claimed in claim 20 in which the alcohol is isopropyl alcohol.
Claim 30
Dependent Claim
28 words
A method as claimed in claim 28 in which the concentration of isopropyl alcohol in the first liquid mixture is less than 70% by weight of the mixture.
Claim 31
Dependent Claim
28 words
A method as claimed in claim 29 in which the concentration of isopropyl alcohol in the first liquid mixture is 10% to 40% by weight of the mixture.
Claim 32
Dependent Claim
28 words
A method as claimed in claim 30 in which the concentration of isopropyl alcohol in the first liquid mixture is 22% to 27% by weight of the mixture.
Claim 33
Dependent Claim
48 words
A method as claimed in claim 28 in which the concentration of isopropanol in the first liquid mixture is between 10% and 70% by weight and in which the concentration of isopropanol in the second liquid mixture is from that of the azeotrope up to 14% by weight.
Claim 34
Dependent Claim
51 words
A method as claimed in claim 32 in which the concentration of isopropanol in the first liquid mixture is from 22% to 27% by weight of the mixture and in which the concentration of isopropanol in the second liquid mixture is from that of the azeotrope up to 7% by weight.
Claim 35
Dependent Claim
38 words
A method as claimed in claim 1 in which the second liquid mixture has a concentration of the auxiliary solvent ranging from that of the azeotrope to not more than 11% by weight above that of the azeotrope.
Claim 36
Dependent Claim
38 words
A method as claimed in claim 34 in which the second liquid mixture has a concentration of the auxiliary solvent ranging from that of the azeotrope to not more than 5% by weight above that of the azeotrope.
Claim 37
Dependent Claim
20 words
A method as claimed in claim 1 wherein the temperature of the second liquid mixture is at least 30° C.
Claim 38
Dependent Claim
23 words
A method as claimed in claim 36 wherein the temperature of both the first and second liquid mixtures is at least 40° C.
Claim 39
Dependent Claim
27 words
A method as claimed in claim 37 wherein the liquid mixtures comprise 1,1,2-trichloro-1,2,2-trifluoroethane and isopropanol and the temperature thereof is in the range 45° to 50° C.
Claim 40
Dependent Claim
47 words
A method as claimed in claim 1 in which the contaminated article is contacted with said first liquid mixture, withdrawn to a vapour zone above said first liquid mixture and rinsed with said second liquid mixture which is obtained by condensation of vapours from said vapour zone.
Claim 41
Dependent Claim
61 words
A method as claimed in claim 39 in which the article is immersed in said first liquid mixture, withdrawn through and out of said vapour zone, allowed to cool and then returned to said vapour zone where it is then rinsed by said second liquid mixture derived by direct condensation of vapours from said vapour zone on to said cooled article.
Claim 42
Dependent Claim
45 words
A method as claimed in claim 1 wherein said first and second liquid mixtures are in compartments separate from each other and not possessing a common vapour zone, and vapours from above said first heated mixture are condensed and returned to the second liquid mixture.
Claim 43
Dependent Claim
23 words
A method as claimed in claim 1 in which the article is a printed circuit or a component thereof contaminated with flux residues.
References Cited (Backward Citations)
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US2310569A
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US3085918A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |