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US4350602A
Expired / Lapsed
US
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Fusing fluid for solder-plated circuit boards
Assignee: Individual
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Filing: 1980-12-18
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Granted: 1982-09-21
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Expires: 2000-12-18
Abstract
Abstract An improved fusing fluid or protectively coating solder-plated printed circuit conductors while they are heated to fuse the solder. Certain prior fusing fluids tend to pull away from portions of the molten solder surface, leaving them unprotected from oxidation. The improved fluid contains a small percentage of phenothiazine or a homologue, which promote complete wetting of the solder surface without causing the foaming and cleaning difficulties associated with surfactants.
Inventors
- 👤 Harold Schiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:27
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/22; B23K35/36; B23K35/3612
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
127 words
A radiation fusing fluid for coating solder-plated electrical circuit boards prior to heating by radiation to fuse the solder plating, said fluid being essentially a mixture of the following: (a) viscous water-soluble organic compounds selected from the general group consisting of: polyoxyalkylene ether containing methyl side chains and terminal hydroxyl groups; polyalkylene glycol; polyoxyalkylene glycol; polyoxyalkylene adducts of butanol: these constituting about 40 to 60 percent of the total; (b) a volatile solvent drivable off at the solder fusing temperature of around 204° C., constituting about 60 to 40 percent of the total; (c) an activator constituting about 1 to 3 percent of the total; and (d) at least about 0.05 percent by weight of an additive selected from the group consisting of phenothiazine and dioctyl phenothiazine.
Claim 2
Dependent Claim
127 words
A radiation fusing fluid for coating solder-plated electrical circuit boards prior to heating by radiation to fuse the solder plating, said fluid being essentially a mixture of the following: (a) viscous water-soluble organic compounds selected from the general group consisting of: polyoxyalkylene ether containing methyl side chains and terminal hydroxyl groups; polyalkylene glycol; polyoxyalkylene glycol; polyoxyalkylene adducts of butanol: these constituting about 40 to 60 percent of the total; (b) a volatile solvent drivable off at the solder fusing temperature of around 204° C., constituting about 60 to 40 percent of the total; (c) an activator constituting about 1 to 3 percent of the total; and (d) at least about 0.05 percent by weight of an additive selected from the group consisting of phenothiazine and dioctyl phenothiazine.
Claim 3
Dependent Claim
12 words
A fluid as in claim 1 wherein said activator is hydrochloric acid.
Claim 4
Dependent Claim
13 words
A fluid as in claims 1 or 2 wherein said additive is phenothiazine.
Claim 5
Dependent Claim
14 words
A fluid as in claims 1 or 2 wherein said additive is dioctyl phenothiazine.
Claim 6
Dependent Claim
14 words
A fluid as in claims 1 or 2 wherein said solvent is isopropyl alcohol.
Claim 7
Dependent Claim
21 words
A fluid as in claim 5 wherein the proportion by weight of said additive is between about 0.1 and 0.2 percent.
Claim 8
Dependent Claim
38 words
A fluid as in claim 6 wherein said compounds are: polyethylene glycol, about 30 percent and polyalkylene glycol, about 15 percent; said solvent is isopropyl alcohol, about 54 percent; and said activator is hydrochloric acid, about 1 percent.
References Cited (Backward Citations)
US3779927A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-20 | 1990-03-22 | 1990-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-20 | 1994-03-22 | 1994-09-21 | $7700.00 | Window Closed / Lapsed |