KR20010008931A - Electrical resistance humidity sensor comprised of an organic polymer - Google Patents

Abstract

PURPOSE: An electric resistance type organic polymer humidity sensor is provided to improve an impedance characteristics within a commercial humidity range and a response speed to be applied to equipments requiring humidity measurement. CONSTITUTION: An electric resistance type organic polymer humidity sensor(10) includes a humidity reducing film(12), an electrode(14) for maintaining electric contact with the humidity reducing film, an electrode snap(16) for fixing the electrode, and a terminal(18) for connecting the electrode to an outside, wherein the humidity reducing film is formed of an alkali metal salt of a polymetacryl acid alkylester copolymer in which a hydroxide of an alkali metal is saponified into the copolymer and the alkali metal is replaced with a relative ion after introducing a hydroxyl group by reacting hydrogen halide under the existence of acidic solution with a synthesized polymetacryl acid alkylester copolymer in which a metacryl acid alkylester derivative is mixed with a comonomer having at least more than one vinyl group.

Description

Electrical resistance humidity sensor comprised of an organic polymer}

The present invention relates to a humidity sensor using an organic polymer film containing a metal salt as a moisture-sensitive film, and more particularly, a methacrylic acid alkyl ester monomer and a methacrylic acid alkyl ester polymer containing a metal salt as a polymer film for sensing humidity and at least one vinyl. The present invention relates to an electrically resistive organic polymer humidity sensor using a copolymer having a group with a comonomer having a group as a moisture-sensitive film and using a characteristic in which impedance changes according to changes in humidity in air.

The electrical resistance organic polymer film humidity sensor is a humidity sensor that senses humidity by using the phenomenon that the impedance of the polymer film changes as the humidity sensitive film is applied to the electrode formed on the alumina substrate. to be.

The electrical resistance humidity sensor using the electrolyte polymer membrane as a moisture absorber exhibits electrical conductivity after dissociation of the electrolyte polymer membrane after absorbing the surrounding moisture, so that the impedance is continuous between 0 to 100% RH (Relative Humidity). To change. Therefore, the relative humidity can be measured accurately.

Conventional organic polymer film humidity sensor can be largely divided into anionic polymer humidity sensor and cationic polymer film humidity sensor. Anionic polymers are polymers in which the main chain of the polymer acts as a cation and the relative ion (gegen ion) affects the electrical conductivity. Cationic polymers are polymers in which the main chain of the polymer acts as an anion and affects electrical conductivity. It refers to a polymer in which the counterion is a cation.

Anionic polymer membrane humidity sensors include 1- (2-hydroxy) -3-methacryloxypropyl trimethylammonium chloride, quaternized poly (4-vinyl pyridine), N, N, N-trimethyl ammonoethyl methacrylamide Halide, N, N-dimethyl aminoethyl methacrylamide, allyl dimethylaminopropyl diallyl ammonium chloride and sulfur dioxide copolymer, 2-methacryloxyethyl alkyldimethylammonium halide, acrylic, vinyl, styrene or methacrylicoxyalkyl dimethylamino Ethyl phosphate, N, N-dimethyl-3,5-dimethylene piperidinium chloride, quaternary alkylammonium sulfonate, chloromethyl styryl ammonium salt, polyionene and a trialkoxy quaternary ammonium salt of styrene or methacrylic acid Is used.

Recently, monomers including phosphonium salts and sulfonium salts have been used, and quaternary ammonium salts have been used for most humidity sensors, and some have been put to practical use.

However, in anionic moisture sensitive materials, since the counterion is an anion, the ion radius is larger than that of the cation. Therefore, since the ion mobility is smaller than the cation, the response speed of the humidity sensor is lowered, which makes it difficult to use the device in which the response speed is important.

Therefore, in order to improve the response speed, the use of a cationic moisture sensitive material is preferable. Monomers used as cationic moisture sensitive materials are mainly salts of sulfonic acid, carboxylic acid and phosphoric acid.

However, in the cationic moisture-sensitive material, the polymerization is difficult, and even if it is polymerized, there is a problem that the water resistance of the humidity sensor is greatly reduced due to the small molecular weight. In particular, when polymerizing polyalkylmethacrylic acid to polymerize from alkylmethacrylic acid as a monomer, it is impossible to obtain a polymer having a molecular weight of 100,000 or more because the carboxyl group forms a resonance structure and prevents polymerization from occurring. Moreover, even if it is a commercial polymethylmethacrylic acid, molecular weight becomes 10,000 or more.

The present invention has been made to solve the conventional problems and problems as described above, the object of the present invention has excellent impedance characteristics in the range of commercial humidity and in particular the response speed is important, the response speed is important devices and humidifiers, dehumidifiers, humidity An object of the present invention is to provide an electrical resistance type cationic organic polymer humidity sensor that can be used in a device requiring humidity measurement such as a controller or a dryer.

1 is a structural diagram of an electrical resistance organic polymer humidity sensor manufactured according to the present invention,

2 is a graph showing the resistance characteristics of the electrical resistance organic polymer humidity sensor manufactured according to the present invention, and

3 is a graph showing the response speed of the electrical resistance organic polymer humidity sensor manufactured according to the present invention.

<Explanation of symbols for main parts of drawing>

10: organic polymer humidity sensor 12: moisture sensitive film

14 electrode 16 electrode snap

18: terminal

In order to achieve the above object, the present invention,

An electric resistance organic polymer humidity sensor comprising a moisture sensitive film, an electrode maintaining electrical contact with the moisture sensitive film, an electrode snap fixing the electrode, and a terminal connecting the electrode to the outside,

The moisture-sensitive membrane is mixed with a methacrylic acid alkyl ester derivative and a comonomer having at least one vinyl group to synthesize a polymethacrylic acid alkyl ester copolymer by a general method, and then reacted with a hydrogen halide in the presence of an acidic solution to introduce a hydroxyl group. Alkali metal salts of polymethacrylic acid alkyl ester copolymers obtained by saponifying a polymethacrylic acid alkyl ester copolymer having the hydroxyl group introduced therein with hydroxides of alkali metals or alkaline earth metals and replacing the alkali metals or alkaline earth metals with counter ions, or It provides an electrical resistance organic polymer humidity sensor, characterized in that the alkali earth metal salt of the polymethacrylic acid alkyl ester copolymer.

Hereinafter, an electrical resistance type cationic organic polymer humidity sensor according to the present invention will be described with reference to the accompanying drawings.

In the present invention, first, a polymethacrylic acid alkyl ester copolymer is synthesized with vinyl comonomers in a general manner using methacrylic acid alkyl ester as a monomer, and then the polymethacrylic acid alkyl ester copolymer is hydrogen halide in the presence of an acidic solution. And a hydroxy group was introduced into the polymethacrylic acid alkyl ester copolymer to synthesize a polyalkylmethacrylic acid copolymer having a large molecular weight.

The hydroxy group-introduced polymethacrylic acid alkyl ester copolymer is hydrolyzed with a hydroxide of an alkali metal or alkaline earth metal to replace hydrogen of the carboxylic acid portion of the polymethacrylic acid alkyl ester with a counterion.

1 is a structural diagram of an electrical resistance organic polymer humidity sensor manufactured according to the present invention.

The organic polymer humidity sensor 10 according to the present invention includes a moisture sensitive film 12, an electrode 14 for maintaining electrical contact with the moisture sensitive film 12, an electrode snap 16 for fixing the electrode 14, and an electrode ( And a terminal 18 for connecting 14 to the outside.

At this time, the moisture-sensitive film 12 is made of copolymerized with comonomers having a methacrylic acid monomer and a at least one vinyl group containing a metal salt having the structure of the following general formula (1) or (2).

[Formula 1]

Here, M is an alkali metal, that is, Group 1 elements on the periodic table.

[Formula 2]

Where M is an alkaline earth metal, ie group 2 elements on the periodic table.

The organic polymer humidity sensor 10 is a moisture absorbent film 12, the impedance of which varies depending on humidity, as a moisture absorbent, as shown in the general formula (1) or (2) after introducing a hydroxy group to the polymethacrylic acid alkyl ester, alkali metal or alkaline earth Copolymerized with a polymer saponified with a hydroxide of a metal or comonomers having one or more vinyl groups to introduce a hydroxy group and to form a copolymer saponified with an alkali metal or alkaline earth metal hydroxide, followed by a pair of terminals (18) and the humidity electrode of the electrode snap 16 containing the silver electrode 14 and silver-palladium are deposited and dried to form a moisture-sensitive film (12).

The polyalkylmethacrylic acid prepared in the present invention can control the introduction of a hydroxy group to 0 to 100% by changing the reaction time and conditions, preferably introducing a hydroxy group to 60 to 100%. In addition, saponification with hydroxides of alkali metals or alkaline earth metals can also control saponification from 0 to 100% by changing the reaction time and conditions, preferably saponification to 50 to 100%.

In the present invention, in order to control the amount of ions affecting the impedance, the amount of polymethacrylic acid alkyl ester having hydroxy group introduced and the hydroxide of alkali metal or alkaline earth metal and the vinyl comonomer, for example, vinyl or By adjusting the length of vinylpyridine, styrene, alphamethylstyrene, alkyl acrylate, divinylbenzene, alkylenebisacrylic ester, alkylene bismethacrylic ester copolymer, the range of 10 ² ~ 10 ⁸ Ω according to the ambient humidity It may have an impedance of.

The saponification with hydroxides of alkali metals or alkaline earth metals for synthesizing the metal salts of the polyalkylmethacrylic acid copolymers can be easily understood by those skilled in the art, and the introduction of hydroxyl groups Solvents used for saponification may also be those used in conventional reactions.

In particular, a protective film may be further formed to protect the moisture-sensitive film coated in the present invention from various external environments such as an organic solvent.

<Example 1 to Example 5>

The methacrylic acid alkyl ester monomer and the styrene monomer were respectively 1: 1 (Example 1), 1: 2 (Example 2), 1: 3 (Example 3), 2: 1 (Example 4), 3: 1 ( The alkali metal salt of the polyalkylmethacrylate styrene copolymer was copolymerized at the ratio of Example 5) and reacted with a hydrogen halide in the presence of an acidic solution to saponify a polyalkylmethacrylate styrene copolymer having a hydroxyl group introduced therein with an alkali metal hydroxide. Was prepared as a 7% by weight solution in water. A humidity sensor consisting of a pair of terminals 4, a silver electrode 2, and an electrode snap 3 containing silver-palladium was deposited and dried to prepare a final humidity sensor.

Humidity sensors were manufactured to observe the characteristics by measuring the impedance at 20 ~ 95% RH, the results are shown in Figure 2, it can be seen that the response speed has an excellent response speed as shown in FIG.

<conclusion>

Since the starting material started from a high degree of polymerization, it was possible to manufacture an electrical resistance organic polymer humidity sensor with excellent water resistance and response speed.

As mentioned above, the electrical resistance organic polymer humidity sensor manufactured by the present invention has a good response speed, and can be suitably used in machines and devices requiring humidity measurement such as a humidifier or a dehumidifier.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (6)

A moisture sensitive film 12, an electrode 14 for maintaining electrical contact with the moisture sensitive film 12, an electrode snap 16 for fixing the electrode 14, and a terminal 18 for connecting the electrode 14 to the outside. In the electrical resistance organic polymer humidity sensor 10 comprising a), The moisture-sensitive film 12 is mixed with a methacrylic acid alkyl ester derivative and a comonomer having at least one vinyl group to synthesize a polymethacrylic acid alkyl ester copolymer by a general method, and then react with a hydrogen halide in the presence of an acidic solution. A hydroxy group is introduced, and the polymethacrylic acid alkyl ester copolymer into which the hydroxy group is introduced is made of an alkali metal salt of a polymethacrylic acid alkyl ester copolymer in which a alkali metal is substituted with a hydroxide of an alkali metal to replace the alkali metal with a counterion. Electrical resistance organic polymer humidity sensor. 2. An electrically resistive organic polymer humidity sensor according to claim 1, wherein an alkali metal salt of said polymethacrylic acid alkyl ester copolymer is represented by the following general formula (1). [Formula 1] Here, M is an alkali metal, that is, Group 1 elements on the periodic table. The method of claim 1, wherein the comonomer is a material selected from the group consisting of vinyl, vinylpyridine, styrene, alphamethylstyrene, alkyl acrylates, divinylbenzenes, alkali bisacryl esters and alkylene bismethacrylic esters. Resistive organic polymer humidity sensor. A moisture sensitive film 12, an electrode 14 for maintaining electrical contact with the moisture sensitive film 12, an electrode snap 16 for fixing the electrode 14, and a terminal 18 for connecting the electrode 14 to the outside. In the electrical resistance organic polymer humidity sensor 10 comprising a), The moisture-sensitive film 12 is mixed with a methacrylic acid alkyl ester derivative and a comonomer having at least one vinyl group to synthesize a polymethacrylic acid alkyl ester copolymer by a general method, and then react with a hydrogen halide in the presence of an acidic solution. What is made of the alkaline earth metal salt of the polymethacrylic-acid alkylester copolymer which introduce | transduced a hydroxyl group, saponified with the hydroxide of an alkaline-earth metal to the polymethacrylic-acid alkylester copolymer which the said hydroxyl group was introduce | transduced, and substituted the said alkaline-earth metal with a counter ion Electrical resistance organic polymer humidity sensor. 5. The organic resistance type organic polymer humidity sensor according to claim 4, wherein the alkaline earth metal salt of the polymethacrylic acid alkyl ester copolymer is represented by the following general formula (1). [Formula 2] Where M is an alkaline earth metal, ie group 2 elements on the periodic table. 5. The method of claim 4, wherein the comonomer is a material selected from the group consisting of vinyl, vinylpyridine, styrene, alphamethylstyrene, alkyl acrylates, divinylbenzenes, alkaline bisacrylic esters and alkylene bismethacrylic esters. Resistive organic polymer humidity sensor.