KR100852859B1 - Humidity sensor comprising polymeric membrane - Google Patents

Abstract

The present invention includes a vinyl monomer comprising a salt, a copolymer copolymerized with one or more vinyl comonomers and a monomer containing a carboxyl group, a vinyl monomer comprising a salt, one or two vinyl comonomers and a 2-oxazoline A polymer film humidity sensor comprising a moisture sensitive agent formed by crosslinking with an ester-amide bond using a copolymer crosslinking agent copolymerized with a vinyl monomer, comprising: a moisture sensitive film, an electrode maintaining electrical contact with the moisture sensitive film, and the electrode In the polymer membrane humidity sensor comprising an electrode snap to fix the electrode and a terminal connecting the electrode to the outside, the air is a copolymer of a monomer comprising a vinyl monomer, one or two or more vinyl comonomers and a carboxyl group containing the salt. Vinyl monomers containing salts, one or two or more vinyls It characterized by the cross-linked amide bond Chemistry by yirueojim-linking agent to the monomer and a copolymer obtained by copolymerizing a vinyl monomer containing a 2-oxazoline ester.

Humidity sensor, Carboxylic functional group, 2-oxazoline crosslinker, Crosslinked electrolyte polymer, Water resistance

Description

Humidity sensor comprising polymeric membrane

1 is a configuration diagram schematically showing an electrode of a polymer film humidity sensor according to the present invention.

Figure 2 shows the copolymer and copolymer cross-linking agent forming a moisture-sensitive film in the formula.

Figure 3 shows the chemical structural formula which is the crosslinking of the copolymer forming the moisture-sensitive film and the copolymer crosslinking agent.

Figure 4 is a MEPAB / AA / BMA = 10/2/8 copolymer used in the polymer film humidity sensor prepared according to the present invention MEPAB / IPO / BMA = 10/1/9, 10/2/8, 10/3 It is a graph showing the moisture sensitivity of the moisture-sensitive film crosslinked with / 7, 10/4/6 and 10/6/4.

Figure 5 is a moisture-sensitive cross-linked MEPAB / AA / BMA = 10/2/8 MEPAB / IPO / BMA = 10/2/8 and 10/6/4 copolymer used in the polymer film humidity sensor prepared according to the present invention It is a graph showing the hysteresis characteristics of the film.

Figure 6 shows the temperature dependence of the moisture-sensitive film cross-linked MEPAB / AA / BMA = 10 / 2/8 copolymer MEPAB / IPO / BMA = 10/2/8 used in the polymer film humidity sensor prepared according to the present invention It is a graph.

Figure 7 shows the frequency dependence of the moisture-sensitive film cross-linked MEPAB / AA / BMA = 10/2/8 copolymer MEPAB / IPO / BMA = 10/2/8 used in the polymer film humidity sensor prepared according to the present invention It is a graph.

Figure 8 shows the response characteristics of the moisture-sensitive film cross-linked MEPAB / AA / BMA = 10 / 2/8 copolymer MEPAB / IPO / BMA = 10/2/8 used in the polymer film humidity sensor prepared according to the present invention It is a graph.

Figure 9 is a graph showing the water resistance of the moisture-sensitive film cross-linked MEPAB / AA / BMA = 10 / 2/8 copolymer MEPAB / IPO / BMA = 10/2/8 used in the polymer film humidity sensor prepared according to the present invention to be.
Figure 10 is a schematic diagram showing the structure of a known humidity sensor having the same structure as the polymer film humidity sensor according to the present invention.
* Explanation of symbols for the main parts of the drawings
1: moisture-sensitive film 2: electrode
3: electrode snap 4: terminal

The present invention relates to a polymer film humidity sensor. More specifically, a vinyl monomer comprising a salt, a copolymer of one or more vinyl comonomers and a monomer comprising a carboxyl group is a vinyl monomer comprising a salt, one or two vinyl comonomers and a 2-oxazoline The present invention relates to a polymer film humidity sensor comprising a moisture-sensitive agent formed by crosslinking with an ester-amide bond using a copolymer crosslinking agent copolymerized with a vinyl monomer.

Polymeric moisture-sensitive membranes for humidity detection usually use electrolyte polymers obtained by polymerization of vinyl monomers containing salts. However, since most electrolyte polymers are highly soluble in water, they dissolve in condensation or humid conditions for a long time, and thus have a disadvantage of large change over time.

In order to prevent this, there is a method of copolymerizing with various hydrophobic monomers, but it cannot fundamentally impart water resistance [JS Cho, RY Lee, HM Lee, KH Kim, MS Gong, Polymer (Korea) , 16, 266 (1992). ). Y. Sakai, Y. Sadaoka, K. Ikeuchi, Sensors Actuat. 9, 125 (1986). CW Lee, HW Rhee, and MS Gong, Syn. Met. , 106, 177 (1999). JS Paek, MS Gong, Korean J. Mater. Res ., 5, 715 (1995). TM Kim, JK Park. RY Lee, MS Gong, Korean J. Mater Res . 3, 598 (1995). A method of introducing an electrolyte by graft copolymerization of a monomer containing a salt in a hydrophobic polymer is used, but there is a problem in mass production in the manufacturing process [Y. Sakai, Y. Sadaoka, M. Matsuguchi and VL Rao, Humidity sensor using microporous film of polyethylene-graft-poly- (2-hydroxy-3-methacryloxy propyl trimethyl-ammonium chloride), J. Mater. Sci. 24 (1989) 101-104. A method of directly bonding an electrolyte gel to an electrode substrate such as alumina or glass has also been attempted [Y. Sakai, Y. Sadaoka, M. Shimada, Humidity sensors based on organo-polysiloxanes having hydrophilic groups, Sens. Actuators B, 16 (1989) 359-367.]. In addition, a method of introducing a functional group such as amine or phosphine, which may undergo quaternary chloride, into a polymer, mixing with a dihalide curing agent, and applying it to an electrode, and then applying a high crosslinking by thermal crosslinking is also applied. Recently, various methods such as improving water resistance have been applied by forming an interpenetrating polymer network (IPN) of an electrolyte polymer and a hydrophobic polymer [Y. Sakai, M. Matsuguchi, Y. Sadaoka and K. Hirayama, "A Humidity sensor composed of interpenetrating polymer network of hydrophilic and hydrophobic methacrylate polymer", J. Electrochem. Soc ., 140, 432-436 (1993).]. However, in view of the manufacturing process, only a part of the above methods are used in a limited humidity sensor including a moisture sensitive film.

Copolymers containing phosphine, pyridine and tertiary amine groups may be mixed with α, ω-dihaloalkanes or copolymers containing alkyl halides or benzyl halides in the opposite way before being applied to the electrodes. The moisture-sensitive film formed by forming a quaternary salt with, N ', N'-tetramethylalkylenediamine and crosslinking shows very good water resistance and shows good applicability as a humidity sensor, but contains tertiary amine. It has the disadvantage of applying a polymer or a polymer containing a halide to the electrode and gas phase reaction [Sadaoka, M. Matsuguchi, H. Sakai, Humidity sensor durable at high humidity using simultaneously cross-linked and quaternized poly (chloromethyl styrene), Sens. Actuators B, 25 (1995) 689-691. Y. Sakai, M. Matsuguchi, T. Hurukawa, Humidity sensor using cross-linked poly (chloromethyl styrene), Sens. Actuators B, 66 (2000) 135-138.]. In particular, since the quaternary salt is formed when the crosslinking method is crosslinked, the salt density of the moisture-sensitive film is increased to form a film more sensitive to humidity, and thus has a low resistance in the entire humidity region.

Recently, a humidity sensor using copolymers in which two copolymers react with each other to form a quaternary salt has been published. This method forms a salt when crosslinking proceeds, and thus a high humidity hardening sensor can be manufactured without increasing resistance [MS Gong, SW Joo, BK Choi, Humidity-sensitive properties of cross-linked]. polyelectrolyte prepared from mutually reactive copolymers, J. Mater. Chem. 12, 902-906 (2002); JS Park, MH Lee, HW Rhee and MS Gong, Humidity sensor using cross-linked polyelectrolyte prepared from mutually reactive copolymers containing phosphonium salt, Sens. Actuators B: Chemical , 86, 160-167 (2002) .; MS Gong, CW Lee, SH Park, JS Park, Humidity sensor using gel polyelectrolyte prepared from mutually reactive copolymers, Sens. Actuators B: Chemical , 86, 160-167 (2002). CW Lee, MS GONG, Humidity-sensitive properties of new polyelectrolytes based on the copolymers containing phosphonium salt and phosphine function ", J. Appl. Polym. Sci. 89, 1062-1070 (2003) .; MS Gong and CW Lee, Resistive humidity sensor using polyelectrolytes based on new-type mutally cross-linkable copolymers, Sensors and Actuators B: Chemical , 88, 21-29 (2003) .CW Lee and MS Gong, Resistive humidity sensor using phosphonium salt-containing polyelectrolytes based on the mutually cross-linkable copolymers, Macromolecular Research , 11, 322-327 (2003).].

However, when a solution is prepared by mixing copolymers reactive with each other, the crosslinking reaction proceeds gradually even at room temperature, and thus a change in viscosity is accompanied. Viscosity changes eventually affect the thickness of the film when a moisture-sensitive film is applied by the deposition method. In this case, deviations between the obtained humidity sensors are severe. As a result, after mixing the two liquids, the liquid must be consumed within a predetermined time.

An object of the present invention is a copolymer of a copolymer comprising a monomer comprising a salt, a vinyl comonomer containing one or more monomers and a carboxyl group, a monomer containing a monomer, a vinyl comonomer containing one or more monomers, and a 2-oxazoline It is to provide a polymer film humidity sensor including a new moisture-sensitive film formed by crosslinking a moisture-sensitive agent formed by crosslinking with an ester-amide bond with a copolymer cross-linked copolymer copolymerized vinyl monomer. In this method, when a mixed solution of a crosslinking agent and two liquids does not cause crosslinking reaction at room temperature, it is excellent in stability, and thus long-term storage is possible at room temperature. It is easy to

In the polymer film humidity sensor according to the present invention, in the polymer film humidity sensor comprising a moisture sensitive film, an electrode for maintaining electrical contact with the moisture sensitive film, an electrode snap for fixing the electrode, and a terminal for connecting the electrode to the outside, The film is a copolymer of a copolymer of a monomer comprising a salt, a vinyl comonomer of one or more salts, and a monomer containing a carboxyl group, a vinyl monomer of a salt, a vinyl of one or two vinyl comonomers and a 2-oxazoline It is a thing formed by crosslinking by ester-amide bond with the copolymer crosslinking agent which copolymerized the monomer.

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

In the polymer film humidity sensor according to the present invention, as shown in FIGS. 1 and 10, the moisture sensitive membrane 1, the electrode 2 which maintains electrical contact with the moisture sensitive membrane 1, and the electrode 2 are fixed. In the polymer film humidity sensor comprising an electrode snap (3) and a terminal (4) connecting the electrode (2) to the outside, the moisture-sensitive film (1) is a vinyl monomer, salt containing one or more vinyl balls A copolymer obtained by copolymerizing a monomer copolymerized with a monomer including a carboxyl group with a copolymer of a monomer containing a salt, a vinyl monomer containing one or more vinyl comonomers, and a vinyl monomer containing 2-oxazoline and crosslinking with an ester-amide bond. It is characterized by being made. The polymer membrane humidity sensor shown in FIG. 10 is published as of April 6, 2000 (Korea Patent Publication No. 10-2000-0018982) before the present application date, and registered as August 11, 2000, It is already known before this filing date.

The polymer membrane humidity sensor is a moisture-sensitive agent whose impedance varies according to humidity. A vinyl monomer including salt, a vinyl monomer containing one or two or more vinyl comonomers, and a copolymer comprising a monomer containing a carboxyl group, a monomer containing vinyl salt, 1 or 2 A humidity sensor electrode made of a gold electrode and an electrode containing silver-palladium was deposited on a solution obtained by mixing two solutions of the above-described vinyl comonomer and a copolymer crosslinker copolymerized with a vinyl monomer including 2-oxazoline, and then heating. By crosslinking with an ester-amide bond to form a moisture-sensitive film. In Figure 2, the copolymer and copolymer crosslinking agent constituting the moisture-sensitive film is represented by the chemical formula, and the chemical structural formula of crosslinking the copolymer and copolymer cross-linking agent constituting the moisture-sensitive film is shown.

The vinyl monomer including the salt constituting the copolymer is preferably introduced into the copolymer in an amount of 10 to 90% by weight, and may be introduced in an amount of 30 to 60% by weight. . When the vinyl monomer including the salt is included in less than 30% by weight, the resistance value is insufficient due to the lack of salt content, and when containing more than 60% by weight, the resistance is very low, it is difficult to control the humidity sensitivity.

In addition, the vinyl comonomer constituting the copolymer may include 10 to 70% by weight in the copolymer, preferably 30 to 60% by weight may be introduced. When the vinyl comonomer is included in less than 30% by weight, the salt content is increased to show a low resistance value, and when it contains 60% by weight, the resistance can be very large. The vinyl comonomer may be used in a mixture of two or more kinds, or as a general vinyl comonomer, it is possible to increase the moisture sensitivity and the flexibility of the membrane obtained by controlling the content. In particular, the use of the vinyl comonomer having a low glass transition temperature can improve the flexibility of the obtained moisture-sensitive film and the adhesion with the electrode.

The vinyl monomer comprising a carboxyl group constituting the copolymer is preferably introduced into the copolymer in an amount of 5 to 30% by weight, and preferably in an amount of 10 to 20% by weight. When the vinyl monomer including the carboxyl group is contained in less than 5% by weight, the degree of crosslinking may be insufficient, so that the moisture-sensitive film may be dissolved in water, and when it contains 20% by weight, the resistance may be increased or highly cross-linked to increase the flexibility of the moisture-sensitive film. There may be a change in physical properties such as deterioration.

The vinyl monomer containing the salt constituting the copolymer crosslinking agent is preferably introduced in an amount of 10 to 80% by weight in the crosslinking agent, and preferably may be introduced in an amount of 30 to 60% by weight. When the vinyl monomer containing the salt is included in less than 30% by weight, the salt content is insufficient to show a high resistance value, when containing 60% by weight, the resistance is very small or even after the cross-linking progress will show the phenomenon of dissolving in water Can be.

In addition, the vinyl comonomer constituting the copolymer crosslinking agent may include 10 to 70% by weight of the crosslinking agent, preferably 10 to 60% by weight. When the vinyl comonomer is included in less than 30% by weight, the salt content is increased to show a low resistance value, when containing 60% by weight, it can show a phenomenon that the resistance is very large. The vinyl comonomer may be used in a mixture of two or more kinds, or as a general vinyl comonomer, it is possible to increase the moisture sensitivity and the flexibility of the membrane obtained by controlling the content. In particular, the use of a vinyl comonomer having a low glass transition temperature improves the flexibility of the obtained moisture-sensitive film and the adhesion with the electrode.

The vinyl monomer comprising the oxazoline group constituting the crosslinking agent is preferably introduced in an amount of 5 to 30% by weight in the copolymer crosslinking agent, and preferably may be introduced in an amount of 10 to 20% by weight. When the vinyl monomer including the oxazoline group is included in less than 5% by weight, the degree of crosslinking may be insufficient, so that the moisture-sensitive film may be dissolved in water. When the vinyl monomer is 20% by weight, the resistance is very small or the flexibility of the moisture-sensitive film is reduced. There may be a change in physical properties.

The vinyl monomer including the copolymer and the salt constituting the copolymer constituting the copolymer crosslinker is 1- (2-hydroxy) -3-methacryloxypropyl trimethylammonium halide, quaternary chlorided vinylpyridine, N, N, N-trimethylammonoethyl acrylate halide, N, N, N-trimethylammonoethyl methacrylate halide, allyldialkyl sulfonium halide, 2- (N, N-dimethylaminoethyl) methacrylamide, dimethyl Diallyl ammonium chloride, 2-methacryloxyethylalkyl dimethylammonium halide, 2-methacryloxyethyl hydroxyalkyl dimethylammonium halide, vinylbenzyltrialkyl phosphonium halide having 2 to 18 carbon atoms of an alkyl group, and having 2 to 2 carbon atoms of an aryl group 18 vinylbenzyltriaryl phosphonium halides, sodium styrenesulfonate, sodium allylsulfonate, sodium trialkylphosphate, sodium vinylsulfonate or any of these It may be selected from the group consisting of two or more mixtures. The vinyl comonomer containing the salt is used as necessary, copolymerized in the moisture-sensitive film to increase the density of the salt to improve the humidity-sensitive properties at low humidity, and generally include methacryloxyethyl trimethyl ammonium chloride Oxyethyldimethyl alkyl ammonium halides can be used where the alkyl groups have 1 to 18 carbon atoms and the halides are chlorine and bromine ions. Among other monomers including commercialized quaternary ammonium salts which are polymerizable; Or a group selected from the group consisting of two or more of these.

The vinyl comonomer constituting the copolymer and the copolymer crosslinking agent is used for the purpose of modifying such as flexibility of the moisture-sensitive film, adhesiveness with the electrode, and moisture sensitivity, and the like, and hydroxyethyl acrylate and methacrylate hydroxy. Hydroxyl group-containing vinyl monomers such as ethyl, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxyhexyl acrylate, and hydroxyhexyl methacrylate; N-substituted amide vinyl monomers such as N, N-dimethyl acrylamide and N, N-dimethyl methacrylamide; Alkoxy acrylate vinyl monomers, such as methoxy ethyl acrylate, methoxy ethyl methacrylate, ethoxy ethyl acrylate, and ethoxy ethyl methacrylate; Vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinyl Vinyl monomers such as morpholyl, N-vinyl carboxylic acid amide, styrene, α-methylstyrene, and N-vinyl caprolactam; Cyanoacrylate vinyl monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl acrylate and glycidyl methacrylate; Polyethylene glycol acrylate, polyethylene glycol methacrylate, polypropylene glycol acrylate, polypropylene glycol methacrylate, methoxy ethylene glycol methacrylate, methoxy polyethylene glycol methacrylate, methoxy polypropylene glycol acrylate, methoxy polypropylene glycol methacrylate Glycol-based acrylic ester monomers such as these; Acrylic ester monomers such as tetrahydroperpril acrylate, tetrahydroperpril methacrylate and 2-methoxyethyl acrylate; Monomers such as isoprene, butadiene, isobutylene and vinyl ether; Or a group selected from the group consisting of two or more of these.

Examples of the vinyl monomer including the carboxy group constituting the copolymer include acrylic acid, methacrylic acid, itaconic acid, vinyl acetic acid, vinyl propionic acid, maleic acid, maleic anhydride, fumaric acid, or a mixture of two or more thereof as an acrylic acid derivative or a methacrylic acid derivative. One selected from the group consisting of can be used.

In addition, the vinyl monomer including the oxazoline group forming the copolymer forming the copolymer crosslinking agent is 2-vinyl-2-oxazoline, 2-vinyl-4-vinyl-2-oxazoline, 2-vinyl-5-vinyl- 2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2- (vinyl Benzyloxy-1-methylethyl) -2-oxazoline, 2- (2-hydroxy-1-methylethyl) acrylate, 2- (2-hydroxy-1-methylethyl) methacrylate or two of these One selected from the group consisting of the above mixtures can be used.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. The following examples are intended to illustrate the invention and should not be understood as limiting the scope of the invention.

Example 1

As shown in Table 1 below, a copolymer obtained by copolymerizing a vinyl monomer containing a salt, a vinyl comonomer having one or more monomers, and a vinyl monomer having a carboxyl group as a moisture absorbent was prepared. In the preparation of the copolymer, [2- (methacryloyloxy) ethyl] dimethyl propylammonium bromide (50 mmol), comonomer n-butyl methacrylate (40 mmol) and acrylic acid (10 mmol) are mixed as monomers, Here, the initiator α, α 'azobisisobutyronitrile (0.05 g) was dissolved in anhydrous 2-methoxyethanol (40 g), degassed, and then subjected to radical polymerization at 60 ° C. for 24 hours to produce one copolymer. Was synthesized. After the polymerization was completed, the polymerization solution was reprecipitated in anhydrous ethyl ether to obtain a copolymer. The reprecipitation process was repeated once more and then dried in vacuo to give a white powdery copolymer.

The copolymer used as the crosslinking agent is [2- (methacryloyloxy) ethyl] dimethyl propylammonium bromide (50 mmol) as a monomer, n-butyl methacrylate (45 mmol) as a comonomer and 2-isopropenyl-2- Oxazoline (5 mmol) was mixed, and the initiator α, α 'azobisisobutyronitrile (0.05 g) was dissolved in 40 g of 2-methoxyethanol, placed in a polymerization ampoule and subjected to radicals at 60 ° C. for 12 hours under a nitrogen atmosphere. The polymerization was carried out to synthesize a copolymer used as a crosslinking agent. After the polymerization was completed, methylene chloride was added and reprecipitated in petroleum ether to obtain a copolymer. After repeating the reprecipitation process, it was vacuum dried in a vacuum oven at 50 ℃ to obtain a white powder crosslinking copolymer.

A copolymer (20 g) and a crosslinking agent copolymer (20 g) containing the carboxyl group were uniformly dissolved in dimethyl sulfoxide (800 g) to prepare a solution. In a constant condition of 60% RH (relative humidity) at room temperature, 20 humidity sensor electrodes were vertically inserted into a jig and deposited on the jig to apply the electrode to a moisture-sensitive film according to the present invention. It was. The electrode to which the moisture-sensitive film was applied was left at room temperature immediately while maintaining a horizontal level, and then naturally dried for 10 minutes, and gradually heated to 100 ° C. for 1 hour to further perform a crosslinking reaction. After crosslinking progressed, it vacuum-dried to form the electrode by which the crosslinked copolymer damping film was apply | coated.

Example 2

The copolymer used as the crosslinking agent is [2- (methacryloyloxy) ethyl] dimethyl propylammonium bromide (50 mmol) as a monomer, n-butyl methacrylate (40 mmol) as a comonomer and 2-isopropenyl-2- The same procedure as in Example 1 was carried out except that oxazoline (10 mmol) was mixed and polymerized to use as a crosslinking agent.

Example 3

The copolymer used as the crosslinking agent is [2- (methacryloyloxy) ethyl] dimethyl propylammonium bromide (50 mmol) as a monomer, n-butyl methacrylate (35 mmol) as a comonomer and 2-isopropenyl-2- The same procedure as in Example 1 was carried out except that oxazoline (15 mmol) was mixed and polymerized to use as a crosslinking agent.

Example 4

The copolymer used as the crosslinking agent is [2- (methacryloyloxy) ethyl] dimethyl propylammonium bromide (50 mmol) as a monomer, n-butyl methacrylate (30 mmol) as a comonomer and 2-isopropenyl-2- The same procedure as in Example 1 was carried out except that oxazoline (20 mmol) was mixed and polymerized to use as a crosslinking agent.

Example 5

The copolymer used as the crosslinking agent is [2- (methacryloyloxy) ethyl] dimethyl propylammonium bromide (50 mmol) as a monomer, n-butyl methacrylate (20 mmol) as a comonomer and 2-isopropenyl-2- The same procedure as in Example 1 was carried out except that oxazoline (30 mmol) was mixed and polymerized to use as a crosslinking agent.

Example 6

2-acrylamido-2-methylpropanesulfonic acid sodium salt (50 mmol), n-butyl methacrylate (in place of [2- (methacryloyloxy) ethyl] dimethylpropylammonium bromide in a copolymer containing a carboxyl group) 40 mmol) and acrylic acid (10 mmol), and instead of [2- (methacryloyloxy) ethyl] dimethylpropylammonium bromide in the preparation of a copolymer comprising 2-isopropenyl-2-oxazoline used as a crosslinking agent. Same as Example 1 except using 2-acrylamido-2-methylpropanesulfonic acid sodium salt (50 mmol), n-butyl methacrylate (40 mmol) and 2-isopropenyl-2-oxazoline (10 mmol) It was carried out by the method.

Comparative Example 1

The copolymer was carried out in the same manner as in Example 2 except that glycidyl methacrylate was used instead of 2-isopropenyl oxazoline in the copolymer.

Comparative Example 2

The copolymer (20 g) containing the carboxyl group of Example 2 and the aziridine crosslinking agent (doubled in molar ratio of carboxyl functional groups) as a crosslinking agent were uniformly dissolved in dimethyl sulfoxide (600 g) to prepare a solution. In a constant condition of 60% RH (relative humidity) at room temperature, 20 humidity sensor electrodes were vertically inserted in a jig and deposited on the jig to apply the electrode to the electrode by applying a moisture-sensitive film according to the present invention. It was. The electrode to which the moisture-sensitive film was applied was left to stand at room temperature immediately while being immediately horizontal, naturally dried for 10 minutes, and then gradually heated up at 60 ° C. for 1 hour to further perform a crosslinking reaction. After crosslinking progressed, it vacuum-dried to form the electrode by which the crosslinked copolymer damping film was apply | coated.

Comparative Example 3

Except for using glycidyl methacrylate as a copolymer crosslinking agent was carried out in the same manner as in Example 6.

Comparative Example 4

Except for using an aziridine crosslinking agent (double the molar ratio of the carboxy functional group) as the crosslinking agent was carried out in the same manner as in Example 6.

TABLE 1

TABLE 2

TABLE 3

On the other hand, the resistance value at the relative humidity of the obtained humidity sensor is shown in Table 2. An environmental test was performed on the obtained humidity sensor under the conditions shown in Table 3 below, and the results are shown in Table 4 below.

TABLE 4

The epoxy crosslinking agent used 1, 6- hexanediol diglycidyl ether, and the aziridine crosslinking agent used 1, 1, 1-trimethylol propane triazidyl triester. The electrical properties of the obtained humidity sensor were investigated. Humidity characteristics of the obtained humidity sensor were 25 ° C and 30 RH of TH-NFM-L (-20 ° C 100 ° C, 5% RH 98% RH (20 ° C)). When equilibrated to% RH, the resistance value was measured by adjusting the humidity of the output of the LCR meter (ED LAB (Republic of Korea), model EDC-1630) at 1 kHz and 1 V. Humidification from 20% RH to 95% RH The hysteresis was measured in the order of the dehumidification process from 95% RH to 20% RH, and the temperature dependence coefficient was measured by changing the temperature of the constant temperature / humidity bath to 15 ° C, 25 ° C, and 35 ° C. The dependence of the resistance on the change was measured by varying the output to 100Hz, 1㎑ and 10㎑ The response rate between low humidity and high humidity was saturated solution of MgCl ₂ · 6H ₂ O and saturated solution of K ₂ SO ₄ at 20 ℃. It measured in 33% RH and 94% RH which are relative humidity of.

The manufactured humidity sensors show the measurement results at 20 to 95% RH in FIG. 4, and in addition, hysteresis test results in FIG. 5, temperature dependency test results in FIG. 6, frequency dependency test results in FIG. 7, and response to FIG. 8. The speed and the test results for water resistance are shown in FIG.

As a result of synthesizing the above embodiments, it was confirmed that the humidity sensor according to the present invention has excellent moisture absorption characteristics as shown in the tables and drawings. Copolymer comprising a salt having a carboxyl functional group was confirmed that it can be produced a humidity sensor excellent in water resistance through a high crosslinking by a crosslinking agent containing oxazoline. When the reactivity of the crosslinking agent is high, two-component preservation is inconvenient to mix and use immediately before use. The reaction with the crosslinking agent over time affects the viscosity and the thickness of the moisture-sensitive film applied when the overall deposition is changed. Therefore, the produced humidity sensor is severely different in the characteristics of the samples. As the polymer crosslinking agent was used, it showed excellent moisture absorption property that a stable value could be obtained due to a small variation in the moisture absorption property with time.

The moisture-sensitive film of the comparative example using a general crosslinking agent other than the polymer crosslinking agent showed many changes over time in water resistance, alcohol resistance, and various reliability test results. It was found that the phenomenon occurred due to poor contact with the electrode under various conditions. In the case of the comparative example used in this patent, in the case of the moisture sensitive membrane using a general crosslinking agent, the water resistance was somewhat exhibited by high crosslinking, but after 2 hours, the humidity sensor sample due to the deposition was found to deviate greatly, and the deviation was in a certain humidity range. Appears large. As a result, if a general crosslinking agent is used, in order to produce a product without variation, the moisture-containing liquid containing the crosslinking agent must be consumed in a short time or it must be continuously manufactured and used.

In the present patent, a copolymer containing a carboxyl functional group and a salt is a one-component solution mixed with a copolymer containing an oxazoline and thus has low reactivity at room temperature, thus allowing long-term storage and effectively crosslinking with a crosslinking agent at 100 ° C. It was confirmed that a moisture-sensitive film having a completely three-dimensional network structure and having excellent moisture-sensing properties could be manufactured.

Therefore, according to the present invention, there is an effect of providing a humidity sensor having excellent moisture sensitivity as well as providing a humidity sensor including the same. Recently, a humidifier for the purpose of automation and control system, control system, moisturizing, dehumidification, air conditioning, drying system It can be used as parts such as condensation prevention of cars, video tape recorder (VTR), camcorder, facsimile condensation sensor, high humidity sensor, low temperature and humidity sensor, etc. There is.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (5)

In the polymer film humidity sensor comprising a moisture sensitive film, an electrode for maintaining electrical contact with the moisture sensitive film, an electrode snap for fixing the electrode and a terminal for connecting the electrode to the outside, The moisture-sensitive film comprises a vinyl monomer comprising a salt, a copolymer of one or two or more vinyl comonomers and a monomer comprising a carboxyl group, a vinyl monomer comprising a salt, one or two or more vinyl comonomers, and 2-oxazoline A polymer film humidity sensor comprising a moisture-sensitive agent formed by crosslinking with an ester-amide bond with a copolymer crosslinking agent copolymerized with a vinyl monomer. delete The method of claim 1, The vinyl comonomer constituting the copolymer and the copolymer crosslinking agent includes carboxyl group-containing vinyl monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; Acid anhydride vinyl monomers such as maleic anhydride and itaconic anhydride; Hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxyhexyl acrylate, hydroxyhexyl methacrylate Siloxane group-containing vinyl monomers; N-substituted amide vinyl monomers such as N, N-dimethyl acrylamide and N, N-dimethyl methacrylamide; Alkoxy acrylate vinyl monomers, such as methoxy ethyl acrylate, methoxy ethyl methacrylate, ethoxy ethyl acrylate, and ethoxy ethyl methacrylate; Vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinyl Vinyl monomers such as morpholyl, N-vinyl carboxylic acid amide, styrene, α-methylstyrene, and N-vinyl caprolactam; Cyanoacrylate vinyl monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl acrylate and glycidyl methacrylate; Polyethylene glycol acrylate, polyethylene glycol methacrylate, polypropylene glycol acrylate, polypropylene glycol methacrylate, methoxy ethylene glycol methacrylate, methoxy polyethylene glycol methacrylate, methoxy polypropylene glycol methacrylate, methoxy polypropylene methacrylate Glycol-based acrylic ester monomers such as glycol; Acrylic ester monomers such as tetrahydroperpril acrylate, tetrahydroperpril methacrylate and 2-methoxyethyl acrylate; Monomers such as isoprene, butadiene, isobutylene and vinyl ether; Or a polymer membrane humidity sensor selected from the group consisting of two or more of these mixtures. The method of claim 1, Examples of the vinyl monomer including the carboxy group constituting the copolymer include acrylic acid, methacrylic acid, itaconic acid, vinyl acetic acid, vinyl propionic acid, maleic acid, maleic anhydride, fumaric acid, or a mixture of two or more thereof as an acrylic acid derivative or a methacrylic acid derivative. Polymer membrane humidity sensor, characterized in that selected from the group consisting of. The method of claim 1, Examples of the vinyl monomer including the oxazoline group forming the copolymer forming the crosslinking agent include 2-vinyl-2-oxazoline, 2-vinyl-4-vinyl-2-oxazoline, and 2-vinyl-5-vinyl-2-oxa Sleepy, 2-isopropenyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2- (vinylbenzyloxy- 1-methylethyl) -2-oxazoline, 2- (2-hydroxy-1-methylethyl) acrylate, 2- (2-hydroxy-1-methylethyl) methacrylate or mixtures of two or more thereof Polymer membrane humidity sensor, characterized in that selected from the group consisting of.

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