Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
352 words
A medical electrode (10) adapted for providing electrical contact with a patient's skin comprising: a) a conductive member (18) including means for connecting the medical electrode to an external electrical apparatus; and b) interfacing means comprising a solid sheet of a conductive viscoelastic hydrophilic gel (12), connected electrically with the conductive member, having a face adapted for interfacing electrically with and adhesively to the patient's skin, which sheet (12) is more cohesive than it is adhesive to the patient's skin and is mechanically connected more firmly to the conductive member than it can be adhesively affixed to the patient's skin, thereby enabling concurrent removal of the conductive member and the sheet from the skin after use without leaving a noticeable residue on the skin, characterised in that the hydrophilic gel (12) is a homogenous aqueous mixture, substantially free of unbound water, monomers and cross-linking agents, comprising (i) water; (ii) an amount dissolved in the water of a water soluble electrolyte effective to reduce the transverse electrical resistance of the sheet to an impedance at 60 Hz of less than 1,000 ohms, and iii) an amount dispersed uniformly throughout the water from about 2 to 35 wt% of a cross-linked polymer, effective to form with the water a tacky surfaced viscoelastic solid, which hydrophilic gel is produced by subjecting a liquid film of an aqueous solution, having a viscosity of 2 x 10³ to 2,000 x 10³ cP, of the electrolyte and a water soluble polymer which is radiation cross-linkable having a weight average molecular weight from 0.05-10 x 10⁶ Daltons to an amount of high energy radiation effective to convert the liquid film to a sheet of the viscoelastic solid having an adhesive face which in the rolling ball tack test gives a rolling ball distance of less that about 10mm and an adhesion energy force in the Adhesion Energy Density Determination Test of about 1.96 to 78.4 Nm/m² (2 to 80 g-cm/cm²) which adhesive sheets have greater cohesive strength than adhesive strength, whereby the sheet can be removed from a surface to which it is affixed without leaving a visible residue.
Claim 2
Dependent Claim
27 words
A medical electrode according to claim 1 characterised in that the water, the cross-linked polymer and the electrolyte are substantially the sole constituents of the hydrophilic gel.
Claim 3
Dependent Claim
19 words
A medical electrode according to any preceding claim characterised in that the water soluble polymer comprises linear polyethylene oxide.
Claim 4
Dependent Claim
30 words
A medical electrode according to any preceding claim characterised in that the water soluble polymer has a weight average molecular weight of 0.5 x 10⁶ to 5 x 10⁶ Daltons.
Claim 5
Dependent Claim
21 words
A medical electrode according to any preceding claim characterised in that the hydrophilic gel contains immersed therein a low area-weight scrim.
Claim 6
Dependent Claim
27 words
A medical electrode according to any preceding claim characterised in that the electrolyte is a water soluble salt present in a concentration of 0.1 to 15 wt%.
Claim 7
Dependent Claim
17 words
A medical electrode according to claim 6 characterized in that the water soluble salt is magnesium acetate.
Claim 8
Independent Claim
118 words
A method for the production of a skin interfacing member of a medical electrode as claimed in any one of claims 1 to 7 characterised in that it comprises the steps of subjecting a liquid film of an aqueous solution, having a viscosity of 2 x 10³ to 2,000 x 10³ cP, of an electrolyte and 2 to 35 wt% linear water soluble polymer which preferably has a weight average molecular weight of 0.05 x 10⁶ to 10 x 10⁶ Daltons to an amount of high energy radiation effective to convert the liquid film to a sheet of the viscoelastic adhesive solid and thereafter forming the thus produced film into a skin interfacing member of a medical electrode.