Conductive adhesive and biomedical electrode

• US 4,524,087 A
• Filed: 07/18/1983
• Issued: 06/18/1985
• Est. Priority Date: 01/23/1980
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Engel, Michael R.
• Primary Examiner(s): Lusignan, Michael R.
• Application Number:
  US06/514,950
• Time in Patent Office: 701 Days
• Field of Search: 128/639-641, 128/798, 128/802, 427/2, 427/54.1, 427/388.2
• US Class Current: 427/2.12
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61N 1/0456 Specially adapted for transcutaneous electrical nerve stimulation [TENS]
• CPC Class Codes: A61N 1/0492 Patch electrodes A61N1/0412, A61N1/0428 take precedence

Abstract

A biomedical electrode having a conductive adhesive thereon which is derived from an essentially solventless process. The resulting adhesive is characterized in that it is a swellable, dermally-nonirritating conformable, coadhesive, ionic, hydrophilic polymer.

Claims

1. A process for making an essentially dry biomedical electrode comprising of an electrode plate having a first surface and a second surface, means for electrically connecting said electrode plate to a lead wire of an electro-medical device, and a swellable, dermally-nonirritating, conformable, cohesive, ionic, hydrophilic polymeric conductive material on said second surface of said electrode plate for enhancing electrical connection with the skin, said process comprising:

forming said conductive material on said electrode plate by the steps of;

(a) compounding a precursor of said conductive material comprising

(1) a water soluble polyhydric alcohol which is a liquid at about 20°

C.;

(2) an ionic, unsaturated, free radically polymerizable material soluble in said polyhydric alcohol;

(3) a photo initiator; and

(4) a crosslinking agent of a multi-functional unsaturated free radically-polymerizable material;

(b) coating said precursor on said second surface of said electrode plate or onto a releasable transfer sheet; and

(c) polymerizing said coated precursor by exposure to ultraviolet light whereby an electrically conductive pressure-sensitive adhesive layer is formed on said electrode plate or said transfer sheet; and

(d) if formed on said transfer sheet, adhering said adhesive layer to said second surface of said electrode plate.

2. A process for making an essentially dry biomedical electrode comprising of an electrode plate having a first surface and a second surface, means for electrically connecting said electrode plate to a lead wire of an electromedical device, and a swellable, dermally-nonirritating, conformable, cohesive, ionic, hydrophilic polymeric conductive material on said second surface of said electrode plate for enhancing electrical connection with the skin, said process comprising:

forming said conductive material on said electrode plate by the steps of;

(a) compounding a precursor of said conductive material comprising;

(1) a water-soluble polyhydric alcohol which is a liquid at about 20°

C.;

(2) acrylic acid, at least 10 percent of which has been neutralized to form a salt soluble in said polyhydric alcohol;

(3) a photo-initiator; and

(4) a crosslinking agent of a multifunctional unsaturated free radically polymerizable material which is soluble in said polyhydric alcohol;

(b) coating said precursor on said second surface of said electrode plate or onto a releasable transfer sheet; and

(c) polymerizing said coated precursor by exposure to ultraviolet light whereby an electrically conductive pressure-sensitive adhesive layer is formed on said electrode plate or said transfer sheet; and

(d) if formed on said transfer sheet, adhering said adhesive layer to said second surface of said electrode plate.

3. The process according to claim 2 wherein said salt of acrylic acid is potassium acrylate or sodium acrylate.

4. The process according to claim 3 wherein said photo-initiator is benzildimethylketal.

5. The process according to claim 4 wherein paid precursor further comprises at least one non-ionic unsaturated free radically polymerizable monomer or comonomer which is soluble in said polyhydric alcohol.

6. The process according to claim 2 wherein said precursor further provides a tackifier.

7. The process according to claim 2 wherein said tackifier is polyacrylic acid.

8. A process for making an essentially dry biomedical electrode comprising of an electrode plate having a first surface and a second surface, means for electrically connecting said electrode plate to a lead wire of an electro-medical device, and a swellable, dermally-nonirritating, conformable, cohesive, ionic, hydrophilic polymeric conductive material on said second surface of said electrode plate for enhancing electrical connection with the skin, said process comprising:

forming said conductive material on said electrode plate by the steps of;

(a) compounding a precursor of said conductive material comprising;

(2) a water-soluble polyhydric alcohol which is a liquid at about 20°

C.;

(2) an ionic unsaturated free radically polymerizable material which is soluble in said polyhydric alcohol;

(3) a free radical initiator; and

(4) a crosslinking agent of a multifunctional unsaturated free radically polymerizable material;

(b) coating said precursor on said second surface of said electrode plate; and

(c) polymerizing said coated precursor whereby an electrically conductive pressure-sensitive adhesive is formed on said electrode plate.

10. The process according to claim 8 wherein said precursor further comprises at least one non-ionic unsaturated free radically polymerizable monomer or comonomer which is soluble in said polyhydric alcohol.

11. The process according to claim 8 wherein said polyhydric alcohol is glycerol.

12. The process according to claim 11 wherein said ionic material is potassium acrylate.

13. The process according to claim 8 wherein said free radical initiator is a photoinitiator.

9. A process for making an essentially dry biomedical electrode comprising of an electrode plate having a first surface and a second surface, means for electrically connecting said electrode plate to a lead wire of an electromedical device, and a swellable, dermally-nonirritating, conformable, cohesive, ionic, hydrophilic polymeric conductive material on said second surface of said electrode plate for enhancing electrical connection with the skin, said process comprising:

forming said conductive material on said electrode plate by the steps of;

(a) compounding a precursor of said conductive material comprising;

(1) a water-soluble polyhydric alcohol which is a liquid at about 20°

C;

(2) an ionic unsaturate free radically polymerizable material which is soluble in said polyhydric alcohol;

(3) a free radical initiator; and

(4) a crosslinking agent of a multifunctional unsaturated free radically polymerizable material which is soluble in said polyhydric alcohol;

(b) coating said precursor onto a releasable transfer sheet;

(c) polymerizing said coated precursor whereby an electrically conductive pressure-sensitive adhesive is formed on said releasable transfer surface; and

(d) adhering said polymerized electrically-conductive material to said second surface of said electrode plate.

14. The process according to claim 9 wherein said precursor further comprises at least one non-ionic unsaturated free radially polymerizable monomer or comonomer which is soluble in said polyhydric alcohol.

15. The process according to claim 9 wherein said polyhydric alcohol is glycerol.

16. The process according to claim 15 wherein said ionic material is potassium acrylate.

17. The process according to claim 9 wherein said free radical initiator is a photoinitiator.