Patent EP0169059B1 successfully refreshed from Google Patents.
EP0169059B1
Expired / Lapsed
EP
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Flexible, directly solderable conductive compositions, compositions useful in forming them, and their use as coatings on substrates
Assignee: Electro Materials Corp of America
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Filing: 1985-07-17
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Granted: 1988-08-31
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Expires: 2005-07-17
Abstract
Abstract This invention provides solderable, flexible, conductive compositions which may be bonded directly to substrates. The conductive compositions comprise silver, substantially in the form of flake, and resin system, said resin system comprising vinyl chloride/vinyl acetate copolymer, epoxy resin and epoxy hardener. Also provided are methods of preparing compositions useful in forming conductive compositions. Once cured, the conductive compositions may demonstrate good adhesion directly to a substrate in addition to excellent conductivity, solderability and felxibility characteristics.
Inventors
- 👤 Frank Wayne Martin
- 👤 Samson Shahbazi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 09:41
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/02; H05K1/09; H05K1/092; H05K1/095; C; C08; C08K; C08K3/00; C08K3/02; C08K3/08; H01; H01B; H01B1/00; H01B1/20; H01B1/22; Y; Y10; Y10S; Y10S428/00; Y10S428/901
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
179 words
A flexible, directly solderable conductive composition comprising:- (i) silver, substantially in the form of silver flake, the silver flake being particles in which the average distance across each particle is at least 5 times greater than the average thickness of the particle; and (ii) resin system comprising: (a) vinyl chloride/vinyl acetate copolymer having a number average molecular weight of from 14,000 to 35,000, having a weight ratio of vinyl chloride to vinyl acetate of from 80:20 to 90:10, and being free of carboxyl modification; (b) non water-based epoxy resin that does not crosslink at room temperature; and (c) epoxy hardener; the weight ratio of silver to vinyl chloride/vinyl acetate copolymer plus epoxy resin plus epoxy hardener being from 88:12 to 95:5, and the epoxy resin/epoxy hardener being heat curable; with the proviso that the composition does not additionally comprise phenolic resin plus acrylic resin plus polyurethane resin such that the weight ratio of silver to vinyl chloride/vinyl acetate copolymer plus phenol resin plus acrylic resin plus polyurethane resin plus epoxy resin plus epoxy hardener is from 75:25 to 90:10.
Claim 2
Dependent Claim
179 words
A flexible, directly solderable conductive composition comprising:- (i) silver, substantially in the form of silver flake, the silver flake being particles in which the average distance across each particle is at least 5 times greater than the average thickness of the particle; and (ii) resin system comprising: (a) vinyl chloride/vinyl acetate copolymer having a number average molecular weight of from 14,000 to 35,000, having a weight ratio of vinyl chloride to vinyl acetate of from 80:20 to 90:10, and being free of carboxyl modification; (b) non water-based epoxy resin that does not crosslink at room temperature; and (c) epoxy hardener; the weight ratio of silver to vinyl chloride/vinyl acetate copolymer plus epoxy resin plus epoxy hardener being from 88:12 to 95:5, and the epoxy resin/epoxy hardener being heat curable; with the proviso that the composition does not additionally comprise phenolic resin plus acrylic resin plus polyurethane resin such that the weight ratio of silver to vinyl chloride/vinyl acetate copolymer plus phenol resin plus acrylic resin plus polyurethane resin plus epoxy resin plus epoxy hardener is from 75:25 to 90:10.
Claim 3
Dependent Claim
55 words
A composition as claimed in claim 1 wherein the silver is present in an amount of from 88% to 95% by weight and the resin system is present in an amount of from 5% to 12%, said percentages being based on the total weight of silver, vinyl chloride/vinyl acetate copolymer, epoxy resin and epoxy hardener.
Claim 4
Dependent Claim
38 words
A composition as claimed in claim 1 or claim 2, wherein the weight ratio of (b) to (c) is from 30:70 to 40:60, and/or the weight ratio of (a) to (b) plus (c) is from 100:1 to 2:1.
Claim 5
Dependent Claim
78 words
A composition as claimed in claim 1 or claim 2, wherein the vinyl chloride/vinyl acetate copolymer is present in an amount of from 4% to 7% by weight, the epoxy resin is present in an amount of from 0.25% to 2% by weight, and the epoxy hardener is present in an amount of from 0.5% to 3% by weight, the percentages being based on the total weight of silver, vinyl chloride/vinyl acetate copolymer, epoxy resin and epoxy hardener.
Claim 6
Dependent Claim
29 words
A composition as claimed in any of claims 1 to 4, wherein the overall average of the distance across the silver flakes is from 0.5 micrometres to 50 micrometres.
Claim 7
Dependent Claim
22 words
A composition as claimed in any of claims 1 to 5, wherein the silver is exclusively in the form of silver flake.
Claim 8
Dependent Claim
20 words
An article, which comprises a substrate coated with a conductive composition as claimed in any of claims 1 to 6.
Claim 9
Dependent Claim
15 words
An article as claimed in claim 7, wherein the substrate is a printed circuit board.
Claim 10
Independent Claim
32 words
A method of soldering a conductive composition as claimed in any of claims 1 to 6 which comprises applying solder, at a temperature of up to 205°C, directly to the conductive composition.
Claim 11
Dependent Claim
19 words
A method as claimed in claim 9, wherein the solder is applied by a dip or reflow soldering technique.
Claim 12
Independent Claim
86 words
A method of preparing a composition useful in forming a flexible, directly solderable, conductive composition as claimed in any of claims 1 to 6, the method comprising mixing together (a) a first solution comprising said vinyl chloride/vinyl acetate copolymer dissolved in ketone solvent; (b) a second solution comprising said r-on water-based epoxy resin and said epoxy hardener dissolved in ester solvent; (c) said silver; the weight ratio of the silver to vinyl chloride/vinyl acetate copolymer plus epoxy resin plus epoxy hardener being from 88:12 to 95:5.
Claim 13
Dependent Claim
101 words
A method as claimed in claim 11, wherein: (i) the weight ratio of silver to vinyl chloride/ vinyl acetate copolymer to epoxy resin is from 68:4:4 to 75:6:2; and/or (ii) the weight ratio of epoxy resin to epoxy hardener is from 40:60 to 36:63; and/or (iii) the weight ratio of vinyl chloride/vinyl acetate copolymer to ketone solvent is from 15:85 to 25:75; and/or (iv) the weight ratio of epoxy resin and epoxy hardener to ester solvent is from about 100:1 to about 75:25; and/or (v) the weight ratio of the first solution to the second solution is from 100:1 to 88:12.
Claim 14
Dependent Claim
92 words
A method as claimed in claim 11, wherein the vinyl chloride/vinyl acetate copolymer is present in an amount of from 15% to 25%, by weight based on the weight of the first solution, the epoxy resin and epoxy hardener are present in an amount of from 70% to 99% by weight based on the weight of the second solution, and the silver is present in an amount of from 68% to 75%, based on the total weight of silver, vinyl chloride/vinyl acetate copolymer, epoxy resin, epoxy hardener, ketone solvent and ester solvent.
Claim 15
Independent Claim
30 words
A method, which comprises applying, to a substrate, a composition prepared by a method as claimed in any of claims 11 to 13, and then drying and curing the composition.
Claim 16
Dependent Claim
12 words
A method as claimed in claim 14, wherein the substrate is flexible.
Claim 17
Dependent Claim
33 words
A method as claimed in claim 14 or claim 15, wherein the drying and curing of the composition is effected at a temperature of from 100°C to 170°C from 15 to 60 minutes.
References Cited (Backward Citations)
No citation records indexed.
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