US3904430A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cleaning process using a non-azeotrope forming contaminated cleaning mixture
Assignee: Imperial Chemical Industries Ltd
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Filing: 1973-08-24
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Granted: 1975-09-09
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Expires: 1993-08-24
Abstract
Abstract Printed circuits are cleaned by passing them through a heated non-azeotropic solvent mixture comprising a halogenated hydrocarbon solvent preferably fluorochlorohydrocarbons containing two or three carbon atoms and an auxiliary solvent such as n-butanol, alkoxy alcohols, or cyclic ethers contained in a sump compartment and then rinsing them in a similar body of a solvent mixture but containing a lower proportion of the auxiliary solvent in a rinsing compartment.
Inventors
- 👤 James William Tipping
- 👤 Bernard Patrick Whim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:11
CPC Classifications
C; C11; C11D; C11D7/00; C11D7/22; C11D7/26; C11D7/261; C11D7/50; C11D7/5004; C11D7/5018; C23; C23G; C23G5/00; C23G5/02; C11D7/263; C11D7/267; C11D7/28
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
133 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 FORM A NON-AZEOTROPE-FORMING MIXTURE AND WHEREIN THE CONCENTRATION OF THE AUXILIARY SOLVET IN THE MIXTURE IS AT LEAST 2.5 PARTS BY WEIGHT PER HUNDRED PARTS OF THE FLUORINAED HYDROCARBON SOLVENT, AND SUBSEQUENTLY RINSING THE ARTICLE WITH A SECOND LIQUID NON-AZEOTROPEFORMING MIXTURE CONTAINING THE FLUORINATED HYDROCARBON SOLVENT AND A PROPORITION OF THE AUXILIARY SOLVENT WHICH IS LOWER THAN THAT CONTAINED IN THE FIRST LIQID MIXTURE, BUT AT LEAST EQUAL TO 0.5% BY WEIGHT OF SAID SECOND LIQUID MIXTURE.
Claim 2
Independent Claim
133 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 FORM A NON-AZEOTROPE-FORMING MIXTURE AND WHEREIN THE CONCENTRATION OF THE AUXILIARY SOLVET IN THE MIXTURE IS AT LEAST 2.5 PARTS BY WEIGHT PER HUNDRED PARTS OF THE FLUORINAED HYDROCARBON SOLVENT, AND SUBSEQUENTLY RINSING THE ARTICLE WITH A SECOND LIQUID NON-AZEOTROPEFORMING MIXTURE CONTAINING THE FLUORINATED HYDROCARBON SOLVENT AND A PROPORITION OF THE AUXILIARY SOLVENT WHICH IS LOWER THAN THAT CONTAINED IN THE FIRST LIQID MIXTURE, BUT AT LEAST EQUAL TO 0.5% BY WEIGHT OF SAID SECOND LIQUID MIXTURE.
Claim 3
Dependent Claim
47 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 or the auxiliary solvent in quantities required to maintain the composition of the said first and second liquid mixtures substantially constant.
Claim 4
Dependent Claim
27 words
A method as claimed in claim 2 in which the external source of the fluorinated hydrocarbon solvent and the auxiliary solvent are introduced into a sump compartment.
Claim 5
Dependent Claim
16 words
A method as claimed in claim 1 in which the second liquid mixture is also heated.
Claim 6
Dependent Claim
51 words
A method as claimed in claim 1 which comprises immersing the article in said first heated liquid mixture, said mixture being contained in a sump compartment and subsequently passing the article into said second liquid mixture in a rinsing compartment, the first and second liquid mixtures having a common vapour zone.
Claim 7
Dependent Claim
36 words
A method as claimed in claim 5 in which at least part of the condensate from the vapour of the first and second liquid mixtures is returned to the rinsing compartment containing the second liquid mixture.
Claim 8
Dependent Claim
20 words
A method as claimed in claim 5 in which liquid mixture overflows from said rinsing compartment to said sump compartment.
Claim 9
Dependent Claim
17 words
A method as claimed in claim 5 in which there is employed a plurality of rinsing compartments.
Claim 10
Dependent Claim
13 words
A method according to claim 5 in which the fluorinated hydrocarbon is 1,1,2-trichloro-1,2,2-trifluoroethane.
Claim 11
Dependent Claim
14 words
A method as claimed in claim 5 in which the auxiliary solvent is n-butanol.
Claim 12
Dependent Claim
16 words
A method as claimed in claim 5 in which the auxiliary solvent is an alkoxy alcohol.
Claim 13
Dependent Claim
15 words
A method as claimed in claim 11 in which the alkoxy alcohol is 2-ethoxy ethanol.
Claim 14
Dependent Claim
33 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.
Claim 15
Dependent Claim
16 words
A method as claimed in claim 13 in which the fluorinated hydrocarbon solvent is a fluorochlorohydrocarbon.
Claim 16
Dependent Claim
17 words
A method as claimed in claim 14 in which the fluorochlorohydrocarbon contains two or three carbon atoms.
Claim 17
Dependent Claim
13 words
A method as claimed in claim 15 in which the fluorochlorohydrocarbon is 1,1,2-trichloro-1,2,2-trifluoroethane.
Claim 18
Dependent Claim
14 words
A method as claimed in claim 1 is which the auxiliary solvent is n-butanol.
Claim 19
Dependent Claim
16 words
A method as claimed in claim 1 in which the auxiliary solvent is an alkoxy alcohol.
Claim 20
Dependent Claim
15 words
A method as claimed in claim 18 in which the alkoxy alcohol is 2-methoxy ethanol.
Claim 21
Dependent Claim
15 words
A method as claimed in claim 18 in which the alkoxy alcohol is 2-ethoxy ethanol.
Claim 22
Dependent Claim
15 words
A method as claimed in claim 18 in which the alkoxy alcohol is 2-butoxy ethanol.
Claim 23
Dependent Claim
16 words
A method as claimed in claim 1 in which the auxiliary solvent is a cyclic ether.
Claim 24
Dependent Claim
14 words
A method as claimed in claim 22 in which the cyclic ether is 1,4-dioxane.
Claim 25
Dependent Claim
31 words
A method as claimed in claim 3 in which the concentration of the auxiliary solvent in the sump compartment is not greater than 90% by weight of the liquid mixture therein.
Claim 26
Dependent Claim
28 words
A method as claimed in claim 24 in which the concentration of auxiliary solvent in the sump comparTment is not greater than 70% of the liquid mixture therein.
Claim 27
Dependent Claim
30 words
A method as claimed in claim 25 in which the concentration of auxiliary solvent in the sump compartment is not greater than 40% by weight of the liquid mixture therein.
Claim 28
Dependent Claim
34 words
A method as claimed in claim 1 in which the concentration of auxiliary solvent in the second liquid mixture is in the range of 0.5 to 10% by weight of the second liquid mixture.
Claim 29
Dependent Claim
50 words
A method as claimed in claim 1 in which the auxiliary solvent is n-butanol and the fluorinated hydrocarbon solvent is 1,1,2-trichloro-1,2,2-trifluoroethane and the concentration of n-butanol in 1,1,2-trichloro-1,2,2-trifluoroethane employed in the first liquid mixture in the sump compartment is 15to 25% by weight with reference to the total liquid mixture.
Claim 30
Dependent Claim
39 words
A method as claimed in claim 28 in which the concentration of n-butanol in said trichlorotrifluoroethane employed in the second liquid mixture in the rinsing compartment is 1 to 1.5% by weight with reference to the total liquid mixture.
Claim 31
Dependent Claim
53 words
A method as claimed in claim 1 in which the auxiliary solvent is 1,4-dioxane and the fluorinated hydrocarbon solvent is 1,1,2-trichloro-1,2,2-trifluoroethane and the concentration of 1, 4-dioxane in said trichlorotrifluoroethane employed in the first liquid mixture in the sump compartment is 8 to 12% by weight with reference to the total liquid mixture.
Claim 32
Dependent Claim
39 words
A method as claimed in claim 30 in which the concentration of 1,4-dioxane in said trichlorotrifluoroethane employed in the second liquid mixture in the rinsing compartment is 2 to 4% by weight with reference to the total liquid mixture.
Claim 33
Dependent Claim
30 words
A method as claimed in claim 1 wherein the temperature of the first and second liquid mixtures is at least 30*C and up to the boiling point of the mixtures.
Claim 34
Dependent Claim
26 words
A method as claimed in claim 32 wherein the temperature of said mixtures is at least 40*C and up to the boiling point of the mixtures.
Claim 35
Dependent Claim
31 words
A method as claimed in claim 33 wherein the liquid mixtures have 1,1,2-trichloro-1,2,2-trifluoroethane as the fluorinated hydrocarbon solvent and the temperature of such mixtures is in the range 45*C to 50*C.
Claim 36
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 vapors from the vapor zone.
Claim 37
Dependent Claim
72 words
A method as claimed in claim 35 in which the article is immersed in said first liquid mixture, withdrawn through and out of said vapor zone, allowed to cool above the vapour zone but within a cleaning vessel containing the liquid mixtures and then returned to said vapour zone where it is rinsed by said second liquid mixture derived by condensation of vapours from said vapour zone on to said cooled article.
Claim 38
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 vapor zone, and vapours from above said first liquid mixture are condensed and returned to the second liquid mixture.
References Cited (Backward Citations)
US2153577A
Cited
US2104992A
Cited
US2162656A
Cited
US2220124A
Cited
US3085918A
Cited
US3340199A
Cited
US3553142A
Cited
US3723332A
Cited
US3733218A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |