JPS60153839A - Electrode for living body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a biomedical electrode that is attached to the skin.

Conventionally, devices have been used for detection purposes such as electrocardiograms and electroencephalogram measurement screens, stimulation or current transmission purposes such as low frequency therapy and iontophoresis (iontophoresis), and grounding purposes such as return electrodes for electric scalpels. In order to establish an electrical connection between a conductive element electrically connected to the AIF and the skin of a living body, so-called electrode paste or cream has been applied to the conductive element or the skin. Recently, as an alternative to these electrode pastes and creams, various types of electrodes for biological use that have self-shape retention, skin adhesion, and conductivity have been proposed.

For example, Japanese Unexamined Patent Publication No. 52-95895, No. 55. -8
No. 1635, No. 56-36939, No. 58-
Publication No. 135506 and the like disclose various electrodes for application to the skin whose crystal phase is a crosslinked or non-crosslinked polymer.

However, products based on these non-crosslinked polymers are not suitable for long-term monitoring applications such as Holter electrocardiographs or long-term iontophoresis applications, which have recently become increasingly important. However, it is difficult to maintain stable electrical connection because of fluid deformation due to sweating, etc., and many of the materials based on crosslinked polymers are directly crosslinked from monomers. Since it is a polymer, it may be difficult to avoid biological stimulation or toxicity due to residual monomers.

In view of the above, the main object of the present invention is to provide a substrate that can maintain good dimensional stability and electrical connection without flow deformation even in long-term applications, and that is formed only from compositional elements that have no biologically harmful effects. Wood! ) The object of the present invention is to provide a novel biological electrode consisting of:

The above object is achieved by the electrode of the present invention, the main component of which is a partially acid amide crosslinked reaction product of a carboxyl group-containing hydrophilic polymer and a polyamine and/or polyammonium salt.

Hereinafter, the compositional elements, formulation and reaction conditions, mode of use, characteristics, etc. of the electrode of the present invention will be explained in more detail.

Carboxyl group-containing hydrophilic polymers Homopolymers or copolymers of monomers such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itafonic acid, aconitic acid, citraconic acid, himic acid, etc., or these monomers and ethylene, propylene, butadiene, Isoprene, isobutyne, alkyl vinyl ether (C, ~C
6) Suitable examples include copolymers with various monomers having no carboxyl group, such as vinyl acetate, vinyl chloride, acrylamide, styrene, and vinyl alcohol.

Here, the average molecular weight of the polymer is preferably 10,000 or more, more preferably 100,000 or more, and the preferred ratio of carboxyl group-containing monomers in the polymer is 5+no1.
% or more.

On the other hand, the carboxyl group in the polymer may be in any state of acid anhydride, monovalent metal salt, amine salt, or quaternary ammonium salt, but in the case of carboxylic acid, the pH of the polymer aqueous solution
is generally preferably prepared to a number of 7 or more before being subjected to the reaction.

Polyamine brush ethylenediamine, hexamine, triethylenetetramine, 1-(3-chloroallyl)-3,5+7-)riasa'-1-7zoniadamantane chloride (CTAC),
Various amines or derivatives thereof having a plurality of amide groups to quaternary ammonium groups in the molecule, such as polyethyleneimine, can be suitably used.

The electrode of the present invention contains 5 as the main component of the base material for the entire base material.
-70% by weight, more preferably 10-50% by weight of the aforementioned polymer and 0.1-95% by weight, more preferably 0.1-50% by weight
Although it contains 60% by weight of a partial acid amide crosslinking reaction product with the above-mentioned polyamine, etc., the following additional components may be further added thereto in order to further improve conductivity, adhesiveness, etc.

1. Electrolytes Various electrolytes such as NaCl, KCl, Na2C'O=, potassium citrate, etc. can be added to increase conductivity.

ii, plasticizers ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, triethylene glycol, butanediol, pentadiol, hexylene glycol, octylene Aliphatic glycols such as glycol, polyols such as glycerin, trinotyrolpropane, hexanetriol, polypropylene glycol, polyglycerin, polyvinyl alcohol or its derivatives, and oligosaccharides containing monosaccharides, trisaccharides, or polysaccharide hydrolysates. This can be exemplified as a suitable example.

iii. water It can be added to increase the conductivity and adhesiveness of the base material.

Adhesive emulsions containing vinyl acetate, acrylic, polybutene, etc. as agents for adhesion can be said to be particularly useful in terms of compatibility with the substrate.

■ Hydrophilic polymer karaya gum, guar gum, chitosan, hydrophilic polysaccharide gum such as gelatin, carboxymethyl cellulose, polyvinyl alfur, polyalkylaminoalkyl (meth)
Acrylate, polyvinylpyrinium halide salt,
For improving the rheological properties of any hydrophilic or water-soluble polymers such as polydiallylammonium halide salts, polyaminomethylacrylamide, polyvinylimidacillin, ionene polymers, cationic flocculants such as polyvinyltetraammonium halide salts, etc. can be added to. That is, these water-soluble polymers, in the form of being entrapped in the acid amide link, impart useful viscoelastic properties to the base material.

vi, ethanolamine, methyljetanolamine, jetanol 7mine,
Monovalent amines such as triethanolamine or their quaternary ammonium salts may be added.

On the other hand, in the electrode base material of the present invention, a mixture of an appropriate amount of a plasticizer and the above-mentioned main components or a system in which the above-mentioned various additives are mixed is usually heated under alkaline conditions at 50-100°C and 50-1
It is easily prepared by subjecting it to a time acid amide crosslinking reaction.

Characteristics and usage mode The electrode base material of the present invention prepared in the manner described above is substantially water-insoluble but has appropriate water absorption and swelling properties, so it is suitable for long-term adhesive use. It exhibits dimensional stability and can provide reliable electrical connection between the conductive element and the skin, can also achieve extremely strong skin adhesion without an adhesive, and can trap a relatively large amount of moisture throughout the ester crosslinked network. It must have low impedance characteristics because it can contain the ionic agent without deteriorating its viscoelastic properties, or it must be able to contain the ionic drug at the desired concentration without containing impurity ions, which are particularly undesirable as electrodes for iontophoresis. It has advantages such as being able to be held in

In addition, as mentioned in item 11, the electrode base material of the present invention, which is substantially free of residual monomers that are generally irritating to the skin, can have good biocompatibility.

On the other hand, the electrode crystal phase of the present invention is used in the structure shown in Figure 1 for sensing applications, and on the other hand, it is used in the structure shown in Figure 2 for stimulation or energization applications. That is, in each figure, the electrode crystal phase 1 of the present invention can be electrically connected to the main body of the device as a biological electrode by connecting a conductive element 2.4 made of metal or the like placed thereon to a lead wire. connected and used.

Incidentally, although "2" shows the simplest form, the present invention is not limited to this in any way, and may be used as a composite structure as shown in the attached FIG. 3, for example.

That is, in FIG. 3, the composite electrode is connected to the connection terminal 5.
, a reinforcing insulating tape 6, a crystalline phase 7 of the present invention, a nonwoven fabric or sponge 8, and an adhesive tape 9.

Furthermore, the base material of the present invention may be used by integrally impregnating reinforcing materials such as nonwoven fabrics, sponges, and paper stocks.

[An electrode base material was prepared by subjecting the mixtures of Formulation Examples 1 to 6 below to a partial ester crosslinking reaction at 60° C. for 115 hours. All of the obtained base materials are water-insoluble and have finite water absorption and swelling properties, and also have suitable skin adhesion and low impedance properties (specific resistance: 1 to 1).
]OkΩ·cm).

Formulation example *1) (hehe〇1/88): Poly(acrylamide/acrylic acid)** P(Ill/MAA): Poly(in7)
tyrene/maleic anhydride)

[Brief explanation of the drawing]

FIGS. 1 to 3 are cross-sectional views showing how the biological electrode of the present invention is used. 1.7 ... Electrode base material 2.4.5 ... Conductive element j) ... Insulation protection cover Special applicant: Advance Electrode Co., Ltd. Figure 1

Claims (1)

[Claims] (1) A biological electrode characterized in that the main component is a partial acid amide crosslinking reaction product of a carboxyl group-containing hydrophilic polymer and a polyamine and/or polyammonium salt.