JPH01250222A - Electrolyte paste for leading out bio-potential - Google Patents

Abstract

PURPOSE:To provide the title paste easy in after-treatment, having no possibility exuding to a sticking tape and imparting no unpleasant feeling to an examinee, by crosslinking polyvinyl alcohol by boric acid ions. CONSTITUTION:Ion exchanged water is added to polyvinyl alcohol, potassium borate and paraben to dissolve all of them under heating to prepare an electrolyte paste. Otherwise, in the above mentioned composition, polyhydric alcohol such as propylene glycol is added and, further, a salt such as sodium chloride is added to said composition and dissolved under heating to prepare the electrolyte paste. Since the obtained electrolyte paste is a solid gel and low in viscosity, said paste is prevented from flowing out and reduced in stickiness. Therefore, an electrode is not detached in long-time use and no unpleasant feeling is given to an examinee.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electrolyte paste used when attaching an electrode for deriving a biopotential to a living body.

(Prior Art) In order to derive the biopotential necessary for measuring electrocardiograms and electromyograms, electrode elements must be attached to the skin surface of the living body. Generally, this attachment is performed by fixing the electrode element to the skin surface with adhesive tape, a belt, or the like. The skin surface is normally covered with an insulating layer called the stratum corneum, which is also covered with dirt and lipids. For this reason, it is necessary to create an electrically stable state by reducing the contact resistance between the electrode element and the skin. Furthermore, since the body surface is soft and uneven and expands and contracts in response to body movements, it is necessary to maintain a mechanically stable contact surface between the electrode element and the skin surface.

To solve these problems, an electrolyte paste is used between the electrode element and the skin. Therefore, it is necessary for the electrolyte paste to have excellent electrical and mechanical properties as described above, and consideration must also be given to the living body, such as not giving stimulation to the living body.

There are so-called biological electrodes that are attached to a living body by applying electrolyte paste to the skin surface or electrode surface immediately before use, and types that have an appropriate amount of electrolyte paste applied to the electrode surface in advance and are ready for use. There are two types available: one that does not require the application of electrolyte paste, and one that does not require the application of electrolyte paste. The former includes electroencephalogram electrodes and electrocardiogram test electrodes (for example, suction electrodes, limb electrodes, etc.) that are used repeatedly. The latter includes
Disposable electrodes that are mainly used once and discarded after use (e.g. electrodes for electrocardiogram monitors for ICU/CCU, Holter electrodes)
electrodes, etc.).

The historical trend of such biological electrodes is that reusable electrodes first appeared, and then disposable electrodes appeared. Since electrolyte pastes are used in conjunction with biological electrodes, it is expected that electrolyte pastes will also advance accordingly. Therefore, first an electrolyte paste is created that is easy to use for repeatedly used electrodes, and then an electrolyte paste that is easy to use for disposable electrodes is created. However, since the history of disposable electrodes is short, the electrolyte paste for electrodes that can be used repeatedly as described above is currently used as the electrolyte paste. Since most of these electrolyte pastes must be stored in containers such as tubes, they have low viscosity and fluidity so that they can be easily extruded from tubes and applied to electrodes or the skin. In addition, it is necessary to remove the electrolyte paste from the electrode after use, and most of the pastes are water-soluble because they are wiped off or washed with water.Furthermore, they have a moderate stickiness to make them easier to blend into the skin. In consideration of this, conventionally, adhesives have been made based on a glue such as carboxymethylcellulose cellulose.

(Problems to be Solved by the Invention) When using such a conventional electrolyte paste,
It has disadvantages such as protruding around the electrode, decreasing viscosity as body temperature rises, and furthermore, when sweating, it mixes with the sweat and becomes easy to flow. For this reason, when an electrode is fixed using an adhesive tape, the adhesive strength of the adhesive tape decreases, resulting in the inconvenience that the electrode may fall off. - On the other hand, if the electrode is fixed using a suction cup or a belt, the reduced viscosity or easy flow of the electrolyte paste will not cause the electrode to fall off, but it will cause discomfort to the subject.

The present invention was made in view of these conventional drawbacks.
The purpose is to provide an electrolyte paste that is easy to post-process, has no risk of leaching into the adhesive tape, and does not cause discomfort to the subject.

[Structure of the Invention] (Means for Solving the Problems) The present invention is made by crosslinking polyvinyl alcohol with borate ions.

(Function) The electrolyte paste of the present invention is a solid gel. Moreover, since it has low stickiness, it does not run out and is less sticky.

(Example) Example 1 (Samples 1 to 3 in Table 1) Ion-exchanged water was added to polyvinyl alcohol (hereinafter referred to as PVA), potassium borate, and paraben, and the mixture was heated and dissolved. As shown in Samples 1 to 3 in Table 1, electrolyte pastes were prepared using samples containing different weight percentages of each component. In the table, the numbers of samples with good usage results are marked with a circle. Parabens and ion exchanged water are not shown in Table 1, but are added to both samples. The percentage of parabens is 0.1 for each, and the percentage of ion-exchanged water is the value obtained by subtracting the sum of the percentages of other components from 100 (the same applies to other examples).

As shown in this table, good results were obtained for Sample 2. No solid gel was formed in sample 1, and sample 3
That would make it too hard. Therefore, potassium borate is 0.1~
30% is appropriate.

Example 2 (Samples 4 to 6 in Table 1) PVA, potassium borate, sodium chloride (hereinafter referred to as Na
Cl) and paraben were added to ion-exchanged water and dissolved by heating. As shown in samples 4 to 6 in Table 1, NaCl
Electrolyte pastes were prepared using samples with different weight percentages. Good results were obtained for sample 5.

In this case, the conductivity to the skin is better than that of Sample 2 of Example 1. Regarding Sample 4, the same effect as that of Sample 2 described above is obtained, but no conductive effect on the skin due to the addition of NaCI is observed.

Regarding sample 6, a syneresis phenomenon occurred. Therefore, the appropriate amount of sodium chloride is 0.1 to 10%.

Example 3 (Samples 7 to 9 in Table 1) Potassium chloride (
(hereinafter referred to as C1) was used. Regarding Sample 8, the same conductive effect on the skin as in Sample 5 was obtained. Regarding Sample 7, the same effect as Sample 2 of Example 1 is obtained, but no effect due to the addition of KCI is observed.

Regarding Sample 9, a syneresis phenomenon occurred. Therefore, KCI is 0
．． 1-10% is suitable.

Example 4 (Samples 10 to 12 in Table 1) PVA, potassium borate, propylene glycol (P
G) and paraben were added to ion-exchanged water and dissolved by heating.

As shown in Samples 10 to 12 in Table 1, electrolyte pastes were prepared with samples containing different weight percentages of propylene glycol. Good results were obtained for sample 11. Sample 11
has better plasticity than Sample 2 of Example 1 and blends well with the skin. Regarding sample 10, the same effect as the above-mentioned sample 2 is obtained, but no effect due to the addition of propylene glycol is observed. Sample 12 becomes liquid and cannot be used as an electrolyte paste. Therefore, the appropriate amount of propylene glycol is 0.1 to 30%.

Example 5 (Samples 13 to 15 in Table 1) Glycerin was used in place of propylene glycol in Example 4 above. Regarding Sample 14, the same effect as Sample 11 was obtained. Regarding Sample 13, the same effect as Sample 2 of Example 1 is obtained, but no effect due to the addition of glycerin is observed. Sample 15 becomes liquid and cannot be used as an electrolyte paste. Therefore, the appropriate amount of glycerin is 0.1 to 20%.

Example 6 (Samples 16 to 20 in Table 1) PVA, potassium borate, propylene glycol or glycerin, NaCl or KCI, and paraben were added to ion-exchanged water and dissolved by heating. Sample 16 in Table 1
As shown in Figures 1 to 20, electrolyte pastes were prepared using samples containing different weight percentages of each of the above components. Good results were obtained for samples 17.18.19. These have better conductivity and plasticity to the skin than Sample 2 of Example 1.

Sample 16 does not become a solid gel. Sample 20 is too hard to be suitable as an electrolyte paste.

Table 2 shows the component percentages of the samples that gave good results in each of the above examples and their effects. In Table 2, PVA
Since it varies depending on the degree of polymerization, degree of saponification, and amount of residual vinegar Wi groups, its component percentage is not listed. However, the degree of polymerization is 50
0~2400. Saponification degree 86.5″-99mol/
%, and PVA with a residual acetate group amount of 3% or less is suitable.

As shown in Table 2, a smaller amount of glycerin tends to increase plasticity than propylene glycol.

Further, in Examples 2 and 3, KCI and NaCl were used, but other salts such as CaCl2 may be used. Furthermore, Example 4
Although propylene glycol and glycerin were used in Example 5, other polyhydric alcohols may be used.

Figures 1 and 2 show impedance changes of electrolyte pastes with different salt concentrations. The electrolyte pastes shown in these figures all contain PVA in addition to the salts shown in the figures.
5% potassium borate 1%, glycerin 3%, parabens 0.1% and water (balance).

FIG. 1 shows the temporal change in impedance to the skin obtained when two electrode elements are attached to a living body with an electrolyte paste interposed between them and currents of different frequencies are passed through the electrode elements. The case of 10H2, 1ooHz is shown for the concentrations of C10.6% and 2.0%, respectively. In either case, the change in impedance decreases after approximately 30 minutes have elapsed.

Figure 2 shows how the impedance changes with frequency when two electrodes are bonded together with an electrolyte paste interposed in between and a current is passed through the electrodes, using electrolyte pastes with different salt concentrations. be. As shown in this figure, impedance can be lowered with a smaller amount of KCI than with NaCl.

Note that in both FIGS. 1 and 2, electrode elements with a diameter of 16 mm are used.

Table 1 Table 2 [Effects of the Invention] According to the present invention, the electrolyte paste is not extruded during use, does not become sticky, and does not run off with sweat. Therefore, when electrodes are fixed with adhesive tape, the adhesive strength of the adhesive tape is not reduced, so the electrodes do not fall off even during long-term use. Moreover, it does not cause discomfort to the test subject. Furthermore, after use, the electrolyte paste of the present invention can be easily removed.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the temporal change in the impedance to the skin of the electrolyte pastes of the present invention having different C1 concentrations;
The figure shows the impedance when the frequency of the current applied to the electrolyte pastes of the present invention having different salt concentrations is changed. Agent Patent Attorney Book 1) Takashi o o Oo O. −〇 −o ば） え え −− １、、＞b－１Δbeく巴

Claims (3)

[Claims] (1) An electrolyte paste for deriving biopotential made by crosslinking polyvinyl alcohol with borate ions. (2) Claim (1) containing polyhydric alcohols
The described electrolyte paste for deriving biopotential. (3) Claim (1) or (2) containing added salts.
) electrolyte paste for deriving biopotential.