KR20210126949A - Composition for electrode of the leakage detection sensor and leakage detection sensor using the same - Google Patents

Abstract

The present invention relates to a leakage sensor. More specifically, the present invention aims to provide a composition for forming a detection electrode having corrosion resistance and chemical resistance on a base film and to provide a leakage sensor which is able to backstitch and fix the base film with corrosion resistance and chemical resistance and a cover film by a thread having corrosion resistance and chemical resistance, and prevent exfoliation from occurring. To this end, in accordance with the present invention, the leakage sensor comprises: a base film made of materials having corrosion resistance and chemical resistance; a pair of detection electrodes formed parallelly on an upper surface of the base film in a longitudinal direction by being made of the composition for electrode of the present invention; and a cover film made of materials having corrosion resistance and chemical resistance, and placed parallelly on an upper surface of the base film, and backstitched and fixed on an edge on the base film in a longitudinal direction by a thread having corrosion resistance and chemical resistance.

Description

Composition for electrode of the leakage detection sensor and leakage detection sensor using the same

The present invention relates to a leak detection sensor, and more particularly, to an electrode composition having acid resistance and chemical resistance to form a sensing electrode, and a leak detection sensor for detecting liquid leaking in a contact or non-contact manner using the electrode composition. .

The leak detection sensor of Registered Patent No. 10-1983660 (leak detection device) registered by the present applicant uses a capacitive method to detect various leaking chemical solutions, including conductive and non-conductive chemical solutions such as water, acid and alkali, oil and organic solvents. It has a structure that senses, and the structure is "a base film made of a material having excellent corrosion resistance and chemical resistance; it is formed in a pair at a distance from each other on the upper surface of the base film to form a capacitance by the area and spacing It consists of a conductive line, a cover film made of a material with excellent corrosion resistance and chemical resistance, attached to the upper surface of the base film, and having holes formed at regular intervals to expose the conductive line to the outside. It consists of two layers, the lowermost first layer is formed of copper by etching, the second layer formed above the first layer is formed of a nickel-copper layer by plating, and the second layer is formed of copper. On the upper side, it has a structure in which a third layer is formed by a gold plating method.

Therefore, when the leaked liquid flows in through the hole of the cover film, it is contacted over a pair of conductive lines, and water, conductive and non-conductive chemical solutions, and oil and organic solvents can be distinguished by the change in capacitance value. there will be

However, according to the prior art, when a solution such as acid or alkali comes into contact with the conductive line repeatedly and frequently several times, the conductive line is corroded and damaged, which prevents accurate capacitance from being generated, resulting in a sensing error. there was

In addition, since the conductive line made of metal is formed on the base film, when time passes while exposed to the harsh external environment, the conductive line is peeled off from the base film and damage occurs, and the cover film is also attached to the base film Since it is attached by an adhesive, there is a problem in that the adhesive is cured and the cover film is peeled off by an acid or alkali solution.

<Prior art literature>

1. Registered Patent No. 10-1983660

(Leak detection device)

In order to solve these conventional problems, the present invention provides a composition for an electrode for forming a sensing electrode having corrosion resistance and chemical resistance on a base film, and also provides a base film and a cover film having corrosion resistance and chemical resistance to corrosion resistance and An object of the present invention is to provide a leak detection sensor that prevents peeling by sewing and fixing with a chemical resistant thread.

In addition, the electrode composition is uniformly applied to the film having corrosion resistance and chemical resistance, and the sensing electrode is formed by slitting, and the sensing electrode is sewn to the base film with a thread having corrosion resistance and chemical resistance and fixed. By doing so, a leak detection sensor is provided that prevents peeling from occurring.

The composition for electrodes of the leak detection sensor of the present invention for achieving the above object,

As a binder, a fluororesin, graphene having conductivity, a solvent, and a dispersant are mixed,

The fluororesin is 25 to 35% by weight, the graphene is 1.5 to 2.5% by weight, the solvent is 65 to 75% by weight, and the dispersant is 3.5 to 4.5% by weight is mixed.

In addition, the leak detection sensor of the present invention,

a base film made of a material having corrosion resistance and chemical resistance;

A pair of sensing electrodes formed of the composition for electrodes of the present invention side by side in the longitudinal direction on the upper surface of the base film;

A cover film made of a material having corrosion resistance and chemical resistance, positioned side by side on the upper surface of the base film, and sewn and fixed to the base film by a thread having corrosion resistance and chemical resistance at the edge portion in the longitudinal direction; .

In the sensing electrode, the composition for the electrode is applied to the upper surface of the film having corrosion resistance and chemical resistance, and the film coated with the composition for the electrode is formed by a thread having corrosion resistance and chemical resistance at the edge portion in the longitudinal direction. It is configured to be sewn and fixed to the film.

In another form, the sensing electrode is formed by printing, or

Alternatively, the composition for the electrode is applied to the upper surface of the film having corrosion resistance and chemical resistance, and the film coated with the composition for the electrode is configured to be fixed to the base film by an adhesive.

In addition, holes are formed in the cover film at regular intervals in the longitudinal direction to expose the pair of conductive lines.

The leak detection sensor using the composition for electrodes according to the present invention has corrosion resistance and chemical resistance, so it can detect not only water, but also acids, alkalis, various organic solvents, oils, etc. In the case where leakage is detected and the base film is sewn and fixed by a thread having corrosion resistance and chemical resistance, peeling does not occur even when exposed to a harsh external environment for a long time, thereby greatly improving durability.

In addition, the cover film having corrosion resistance and chemical resistance is also sewn and fixed by the base film and a thread having corrosion resistance and chemical resistance, so that the sensing electrode can be stably protected, as well as not peeling off from the base film, which also improves durability. formed large.

1 is a view showing the structure of a leak detection sensor according to the present invention.
2 is a view showing another form of the leak detection sensor.
3 is a cross-sectional view showing a structure in which a cover film is sewn and fixed to a base film;
4 is a cross-sectional view showing a structure in which a cover film and a conductive line are sewn to a base film and fixed;
5 is a view showing a reduced negatively charged graphene oxide.
6 is a diagram showing a positively charged reduced graphene oxide.
7 is a diagram illustrating an initial charge distribution of a general sensor.
8 is a view showing the initial charge distribution of the sensing line including the charged and reduced graphene oxide applied to the present invention.
9 is a view showing the charge distribution of a common sensor upon contact with a harmful substance.
FIG. 10 is a view showing charge distribution when a sensing line including a charged and reduced graphene oxide comes into contact with a harmful substance according to another embodiment of the present invention.

The above-described objects, features and advantages will be described below in detail with reference to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention.

In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

The terms used in the present invention have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like.

In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the corresponding invention.

Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the embodiments of the present invention illustrated below may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

The embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art.

1 is a diagram showing the structure of a leak detection sensor according to the present invention, FIG. 2 is a diagram showing another form of the leak detection sensor, and FIG. 3 is a diagram showing a structure in which a cover film is sewn to a base film and fixed. .

4 is a view showing a structure in which the cover film and the conductive line are sewn to the base film and fixed.

In the leak detection sensor of the present invention, as shown in FIGS. 1 and 2 , a pair of sensing electrodes 110 and 120 are spaced apart in the longitudinal direction on the upper surface of the base film 100 made of a film material having corrosion resistance and chemical resistance. They are positioned side by side, and a cover film 200 made of a film material having corrosion resistance and chemical resistance, preferably a film material made of a fluorine-based material, is covered and fixed to the upper side of the base film 100 .

Of course, the base film 100 is also formed of a film material having corrosion resistance and chemical resistance, preferably a film material made of a fluorine-based material.

Therefore, when the leaked liquid is located between the sensing electrodes 110 and 120, the leakage state is sensed in a contact or non-contact manner. Holes 210 are formed at regular intervals along the longitudinal direction so as to expose to the outside, and the liquid leaked through the holes 210 flows in to directly contact the sensing electrodes 110 and 120 between the sensing electrodes 110 and 120. Changes in resistance, conductivity, and capacitance are detected.

In the case of the non-contact type, as shown in FIG. 2 , the hole 210 is not formed in the cover film 200 , and when the leaked liquid is located on the upper surface of the cover film 200 , the gap between the sensing electrodes 110 and 120 is It detects the state of leakage by changing the capacitance value.

The pair of sensing electrodes 110 and 120 is formed of a composition that can be used repeatedly while sensing harmful chemical solutions such as acid and alkali by having corrosion resistance and chemical resistance while having conductivity, and the composition is a fluororesin as a binder. Teflon (PFA, PTEF), graphene having conductivity, a solvent, and a dispersant are mixed.

That is, a printable composition is formed using a fluorine-based material and a conductive graphene material as a main material.

The fluororesin has corrosion resistance and chemical resistance, has a liquid form that is cured at 150° C., and is mixed in an amount of 25 to 35% by weight.

The graphene has conductivity, is a component that allows power to flow to the sensing electrodes 110 and 120, is typically formed as a multi-layer to have a stable structure, and is mixed in an amount of 1.5 to 2.5% by weight.

As the solvent, NMP (N-Methyl-2-Pyrrolidone) is used. This NMP solvent is to exfoliate the multi-layer into a single-layer by exfoliating the graphene to a nano size, and 65 to 75 wt% is mixed

Therefore, the conductivity of graphene is very good.

In addition, if necessary, a quick-drying solvent, 2-ethoxyethanol (2-Ethoxyethanol) may be used.

And, the dispersant is mixed in 3.5 to 4.5% by weight.

The electrode composition mixed in this way is in the form of ink and is directly printed on the base film 100 to form the first sensing electrode 110 and the second sensing electrode 120 .

During printing, an additional 8 to 10 wt % of a curing agent (isocyanate) is added to the electrode composition.

Accordingly, the first sensing electrode 110 and the second sensing electrode 120 are printed with the electrode composition side by side on the upper surface of the base film 100 as shown in the cross-sectional view of FIG. 3A, and the base film 100 ), a cover film 200 having a hole 210 formed thereon is positioned, and a thread made of a fluorine-based material having corrosion resistance and chemical resistance along both longitudinal edges of the cover film 200 and the base film 100 , preferably the stitched parts 300 and 310 sewn by a thread made of a Teflon material are densely formed.

Therefore, the cover film 200 is not peeled off from the base film 100 , and only the first sensing electrode 110 and the second sensing electrode 120 are exposed through the hole 210 .

In addition, the first and second sensing electrodes 110 and 120 may be fixed to the base film 100 in other forms as well as printed forms. After printing the composition for an electrode widely to have a uniform thickness on the upper surface, it may be slitted for a long time and attached side by side to the base film 100 by an adhesive.

3( b ) is a cross-sectional structure of a leak detection sensor that detects a leak in a non-contact manner, in a form in which the hole 210 is not formed in the cover film 200 .

Figure 4 (a) shows the slitted first and second sensing electrodes 110 and 120 are located on the upper surface of the base film 100, and both edges thereof are sewn with a Teflon thread long in the longitudinal direction. 320 and 330 are respectively formed and fixed to the base film 100 to have a structure in which peeling does not occur from the base film 100 .

Of course, the cover film 200 in which the hole 210 is formed also has stitched portions 300 and 310 on both sides of which are sewn with Teflon threads, so that not only the cover film 200 but also the first and second sensing electrodes 110 and 120 are peeled off. As this does not occur, the durability is greatly improved and the reliability of detection is also increased.

4( b ) shows a cross-sectional structure in which the hole 210 is not formed in the cover film 200 .

In the above, the base film 100 and the cover film 200 may be fixed by being attached to each other by an adhesive as well as a structure in which they are fixed to each other by a Teflon thread.

On the other hand, graphene included in the composition for electrodes forming the first sensing electrode 110 and the second sensing electrode 120 is converted to graphene oxide in order to shape the sensing performance when detecting leakage by the capacitive method. By doing so, it is used as an electrode while having chemical resistance, chemical resistance, chemical resistance and chemical resistance, and the first sensing electrode 110 is formed by a composition for an electrode including positively charged reduced graphene oxide, and the second The sensing electrode 120 is formed of an electrode composition including negatively charged reduced graphene oxide.

Of course, the first sensing electrode 110 is formed on the electrode composition containing the negatively charged reduced graphene oxide, and the second sensing electrode 120 is an electrode containing the positively charged reduced graphene oxide. It may be formed by the composition for use, and the first sensing electrode 110 and the second sensing electrode 120 have opposite polarities to each other.

In the present invention, graphene is used as a conductive material in the composition for electrodes. Graphene is a two-dimensional carbon sheet made of carbon atoms, and has a large specific surface area, excellent thermal conductivity, and fast electron transfer properties compared to conventional nanomaterials. indicates

Graphene can be obtained by physically separating graphite layer by layer, but this method is not suitable for mass production and it is impossible to manufacture large-area graphene. As another method, there is a chemical exfoliation method of graphite, that is, a manufacturing process through an oxidation process, which can be mass-produced with low manufacturing cost, and functionalization of the produced graphene is possible, so that various applications are possible. You can get a pin.

In the case of graphene oxide, it may have fewer layers than in the case of graphene by a physical method.

Various functional groups such as an epoxy group, a hydroxyl group, a carbonyl group, or a carboxy group exist on the surface of the graphene oxide obtained through the oxidation process.

In order to use such graphene oxide as a component of an electrode, in the present invention, graphene oxide is reduced and used as reduced graphene oxide (rGO).

In particular, in the present invention, when the reduced graphene oxide is prepared by giving the polarity, the reduced graphene oxide having polarity can be used to greatly improve the sensitivity of the sensor, particularly when used as a capacitive sensor.

5 is a view showing reduced graphene oxide that is positively charged, and FIG. 6 is a road showing reduced graphene oxide that is negatively charged, and the composition for an electrode according to the present invention is charged and reduced graphene oxide. A pin is used for the electrode.

Reduced graphene, which can be obtained by reducing graphene oxide, can be used as an electrode because it exhibits conductivity unlike graphene oxide with insulating properties.

In the present invention, in particular, among the reduced graphene oxide, positively charged reduced graphene oxide or negatively charged reduced graphene oxide is used.

The positively charged reduced graphene oxide may have, for example, a surface charge represented by a NH ₃ ⁺ functional group (FIG. 5), and a negatively charged reduced graphene oxide may have a surface charge represented by a COO ⁻ functional group. may appear (FIG. 6).

NH ₃ ⁺ group or ^{COO-oxidation} of the reduced graphene having a functional group is the functional group NH ₃ ⁺ or COO at reduced graphene oxide ^- while remaining the functional group can be obtained by reducing the graphene oxide.

When the reduced graphene oxide is charged, there is an effect on the value of the capacitance change related to the sensitivity of the sensor.

7 is a view showing the initial charge distribution of the sensing electrode of a general sensor, FIG. 8 is a view showing the initial charge distribution of the sensing line including the charged and reduced graphene oxide applied to the present invention, and FIG. It is a diagram showing the charge distribution when the sensor comes into contact with hazardous chemicals.

And, FIG. 10 is a view showing a charge distribution when a sensing line including a charged and reduced graphene oxide comes into contact with a hazardous chemical according to another embodiment of the present invention.

Referring to FIG. 7 , when the conventional electrode does not include a material having a polarity, charges are distributed to the + electrode and the - electrode to obtain an initial charge amount value.

In FIG. 8, in the case where the electrode is coated with charged and reduced graphene oxide, that is, any one electrode (the first sensing electrode 110 or the second sensing electrode 120) used as a + electrode is positively charged. When the graphene oxide is coated, and the negatively charged reduced graphene oxide is coated on another electrode (the second sensing electrode 120 or the first sensing electrode 110) used as an electrode, the voltage is Approval is shown.

When the positively charged reduced graphene oxide is coated on the + electrode, the -charges induced by voltage application are canceled by the positively charged reduced graphene oxide, so that the initial charge value is lowered.

9 and 10, when the electrode of the conventional sensor does not include a polarity and when the electrode is coated with charged and reduced graphene oxide, when exposed to harmful substances, the value of the electric charge depends on the harmful substances, so the same harmful Since the value of the amount of charge by the material is the same, the current value of the amount of charge is similar to both.

Since capacitance depends on the amount of charge, the amount of change in capacitance depends on the difference between the current amount of charge and the amount of initial charge. Therefore, if the initial charge amount becomes smaller, the range of change in the capacitance value becomes wider when the current charge amount is the same. The resolution and sensitivity of the sensor are improved.

That is, when charged and reduced graphene oxide is added to the composition for electrodes as in the present invention, the amount of charge is affected, and thus the sensitivity of the sensor acting as the capacitive type of the present invention can be improved.

The composition for an applied capacitive hazardous material electrode according to the present invention includes charged and reduced graphene oxide, a binder, a solvent, and a curing agent.

In addition, the composition for a capacitive-type hazardous material electrode according to the present invention may further include a dispersing agent and a volatilization retardant for increasing the dispersibility of the charged and reduced graphene oxide.

The composition for an electrode applied in the present invention comprises the steps of mixing a charged and reduced graphene oxide, a binder, a solvent, and a dispersant; A dispersion step of first dispersing the mixture by stirring with a homomixer, and secondarily dispersing the firstly dispersed mixture with a high-pressure disperser; It can be prepared by performing; adding a curing agent to the dispersed mixture.

It is preferable that the curing temperature be completed at 180°C after pre-curing at 100°C.

The first dispersing step is a step of mixing the charged and reduced graphene oxide and fluororesin in a solvent to maximize the capacitance reaction width, and is preferably performed at 5,000 to 7,000 rpm for 1 hour to 2 hours.

The second dispersing of the primary mixture using a high-pressure disperser increases the printability and dispersibility of the electrode composition by crushing and dispersing the mixture under high pressure.

The secondary dispersion may be preferably performed 5 to 10 times under a pressure of 300 to 350 bar.

A curing agent is added to the dispersed mixture and stirring is performed for 10 to 30 minutes at 3,000 to 5,000 rpm using a homomixer.

As described above in detail a specific part of the content of the present invention, for those of ordinary skill in the art, it is clear that this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereby. something to do.

Accordingly, it is intended that the substantial scope of the present invention be defined by the appended claims and their equivalents.

100: base film 110, 120: sensing electrode
200: cover film 210: hole
300,310,320,330: Stitching part

Claims (10)

A composition for an electrode of a leak detection sensor in which a fluororesin as a binder, graphene having conductivity, a solvent, and a dispersant are mixed.
According to claim 1, wherein the fluororesin is 25 to 35% by weight, the graphene is 1.5 to 2.5% by weight, the solvent is 65 to 75% by weight, the dispersant is characterized in that 3.5 to 4.5% by weight are mixed. A composition for an electrode of a leak detection sensor.
According to claim 1, wherein the graphene is a composition for an electrode of a leak detection sensor, characterized in that the reduced graphene oxide.
a base film made of a material having corrosion resistance and chemical resistance;
a pair of first and second sensing electrodes formed of the composition for electrodes of claim 1 in parallel on the upper surface of the base film in the longitudinal direction;
A cover film made of a material having corrosion resistance and chemical resistance and stacked side by side on the upper surface of the base film;
a base film made of a material having corrosion resistance and chemical resistance;
a pair of first and second sensing electrodes formed of the composition for electrodes of claim 1 in parallel on the upper surface of the base film in the longitudinal direction;
A cover film made of a material having corrosion resistance and chemical resistance, located side by side on the upper surface of the base film, and sewn and fixed to the base film by a thread having corrosion resistance and chemical resistance at the edge portion in the longitudinal direction; A leak detection sensor.
The method of claim 5, wherein the sensing electrode is coated with the composition for the electrode on the upper surface of the film having corrosion resistance and chemical resistance, and the film coated with the composition for the electrode has corrosion resistance and chemical resistance at the edge portion in the longitudinal direction. A leak detection sensor, characterized in that it is sewn and fixed to the base film by a thread.
[Claim 6] The leak detection sensor according to any one of claims 4 to 5, wherein the sensing electrode is formed by printing.
The method according to any one of claims 4 to 5, wherein the sensing electrode is coated with the composition for the electrode on the upper surface of the film having corrosion resistance and chemical resistance, and the film coated with the composition for the electrode is applied to the base film. A leak detection sensor, characterized in that it is configured to be fixed by an adhesive.
[Claim 6] The leak detection sensor according to any one of claims 4 to 5, wherein holes are formed in the cover film at regular intervals in the longitudinal direction to expose the pair of sensing electrodes.
6. The method according to any one of claims 4 or 5,
The first sensing electrode is composed of a composition for an electrode comprising positively charged single-unit graphene oxide,
The second sensing electrode is composed of a composition for an electrode comprising negatively charged graphene oxide,
The positively charged reduced graphene oxide has a surface charge represented by an NH ₃ ⁺ functional group, and the negatively charged reduced graphene oxide has a surface charge represented by a COO ^- functional group.

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