JP2003262600A - Humidity sensor element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a humidity sensor element which is superior in water resistance, solvent resistance and gas resistance so that moisture in an atmosphere can be detected and quantitatively determined, which eliminates a hysteresis in a wide humidity region and which has a stable output characteristic and to provide a method of manufacturing the humidity sensor element. <P>SOLUTION: A humidity sensor comprises a pair of electrodes so as to be faced via a gap on an insulating substrate, and it comprises a moisture sensitive membrane on the gap. A contamination and/or an oxide in the uppermost layer of the insulating substrate are removed by a physical means, the insulating substrate is coated with a monomer having an ethyle unsaturated reaction group, and the monomer is polymerized on the insulating substrate so as to form the moisture sensitive membrane. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humidity sensor element manufacturing method and a humidity sensor element for detecting and quantifying moisture in an atmosphere.

[0002]

2. Description of the Related Art Conventionally, as a humidity sensor material (humidity sensitive material) for detecting humidity by a change in electrical characteristics such as an electric resistance value, one using an electrolyte such as lithium chloride, one using a metal oxide, Those using organic polymer compounds are known.

However, electrolytes such as lithium chloride have a narrow range of measured humidity and their properties change due to dew condensation or water leakage, resulting in poor water resistance. Further, the one using a metal oxide has strong water resistance, but has low sensitivity and poor long-term stability as it is, so that a heating and cleaning circuit is required, resulting in high operating cost and complicated sensor structure. Have

On the other hand, among the materials for humidity sensors, organic polymer compounds, especially polymer electrolytes having quaternary ammonium salts, are widely used and highly evaluated for consumer and industrial purposes.

For example, Japanese Examined Patent Publication No. 61-54176 discloses an aggregate of latex particles which is a copolymer of a hydrophobic monomer and an ionic or nonionic hydrophilic monomer and has a hydrophilic surface layer. A moisture-sensitive material consisting of the above is disclosed, and among them, those having a primary to quaternary ammonium salt as a cationic compound are mentioned.

Further, Japanese Patent Publication No. 62-7976 discloses that
A polymer containing 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride was prepared with a polymerization degree of 1
It is disclosed that a polymer obtained by polymerization in the range of 000 to 10,000 is used as a moisture sensitive material.

In addition, Japanese Patent Publication No. 24465/1990.
Is -(N⁺(R₁) (R₂) X^--AN⁺(R₃) (R_Four) X^-
-B)_n− [Where R₁~ R_FourIs an alkyl group, X^-Is halogenio
N, A, B are-(CH₂) _m-(M ≧ 2)]
Ionene polymer thin film or substrate
For the purpose of improving adhesion and water resistance, this polymer and
Of mixtures with other polymers such as ribinylpyrrolidone
It is disclosed that the thin film is used as a thin film of a moisture-sensitive polymer.
There is.

However, in the case of a humidity sensor using a conventional polymer electrolyte as a material for a humidity sensor as exemplified above, water resistance such as partial elution of the polymer electrolyte in a high humidity region, especially in a dew condensation atmosphere. There was also a hysteresis phenomenon that showed different output values even when the humidity was increased and decreased when the humidity was increased. Also 10% RH
In the following low humidity region, it had a high resistance value and it was practically impossible to measure humidity.

Japanese Unexamined Patent Publication (Kokai) No. 7-318526 discloses an example in which an unsaturated bond is introduced into both ends of the above-mentioned ionene polymer to carry out UV crosslinking in order to improve water resistance. In this case, good characteristics and water resistance are obtained with an extremely small film thickness. However, when the film thickness is small, the absolute amount of the polymer is small, and a gas that dissolves in water to form ions (for example, Cl ₂ , N ₂
O _x, it becomes susceptible to the influence of SO _x). In particular,
Serious for civilian use.

If the film thickness is not less than a certain level, even if ions derived from gas are generated in the surface layer, the conductivity is not so affected. However, in the above-mentioned crosslinking method, the swelling of the polymer layer due to water supply is extremely large. However, in order to cause serious problems such as generation of cracks and peeling from the substrate, it is necessary to use a film having a small film thickness of 1 μm or less.

As a method of obtaining adhesion to a substrate with a thick moisture-sensitive film, Japanese Patent Application Laid-Open No. 7-318525 discloses an example of using a silane compound between the substrate and the substrate. In this case, at least two coating operations are required to obtain the moisture-sensitive film, and the silane compound layer is dried before the moisture-sensitive film is applied to form the silane compound layer and the moisture-sensitive film layer. There was a drawback that it took time because it was necessary.

[0012]

The main object of the present invention is to have excellent water resistance, operate stably for a long period of time even in a dew-condensing atmosphere, have good solvent resistance, and to prevent the influence of gases such as acid gas. An object of the present invention is to provide a simple method of manufacturing a humidity sensor element having a humidity sensitive thin film which is difficult to receive and has stable and excellent output characteristics in a wide humidity range, and a humidity sensor.

[0013]

These objects are achieved by the present invention described in (1) to (4) below. (1) In a method of manufacturing a humidity sensor having a pair of electrodes facing each other with a gap on an insulating substrate and having a moisture sensitive thin film on the gap, contaminants and / or oxidation of the outermost surface layer of the insulating substrate. To remove things by physical means,
Then, a method of manufacturing a humidity sensor element, comprising applying a monomer having an ethylenically unsaturated reactive group onto the insulating substrate and then polymerizing the monomer on the insulating substrate to form a moisture sensitive thin film. (2) The method for manufacturing a humidity sensor element according to (1), wherein the physical means is plasma surface treatment. (3) The method for producing a humidity sensor element according to (1) or (2) above, wherein the monomer having an ethylenically unsaturated reactive group contains a quaternary ammonium salt. (4) In a humidity sensor having a pair of electrodes facing each other through a gap on an insulating substrate and having a moisture sensitive thin film on the gap, the insulating substrate is a contaminant and / or an oxide of the outermost layer. A humidity sensor element in which the moisture-sensitive thin film contains a polymer of a monomer having an ethylenically unsaturated reactive group.

[0014]

In the present invention, the moisture sensitive thin film of the conductive polymer is formed so as to cover the pair of electrodes provided on the insulating substrate.

In forming the moisture-sensitive thin film, in the present invention, contaminants and / or oxides existing on the surface layer of the insulating substrate are removed by physical means before coating the moisture-sensitive thin film.

The insulating substrate for forming the moisture sensitive film is generally an alumina substrate, and the outermost layer thereof is covered with contaminants, adsorbed gas, organic substances, oxides of the substrate itself, etc. Although the adhesion is impaired, the adhesion between the insulating substrate and the moisture sensitive thin film can be improved by performing such an operation.

The method using physical means is capable of removing contaminants and organic substances by the method using chemical means, but it is difficult to remove the oxide layer, and there is also a problem of waste liquid after chemical treatment. This is because it is not the preferred method. On the other hand, the method by physical means can remove the above-mentioned contaminants and oxides relatively easily while minimizing the destruction of the base. In addition, there is a wide range of choices for the material to be processed.

Among the several physical means, plasma surface treatment is highly effective and preferred. Plasma surface treatment (hereinafter also referred to as “plasma treatment”) is a surface treatment by etching and implantation by causing active electrons, radicals, ions, and molecules existing in plasma to interact with the surface of an insulating substrate. Reform the state.

The generated plasma changes depending on the plasma generation atmosphere, and it is roughly classified into oxygen plasma and hydrogen plasma depending on the gas species used, but the use of these is preferred.
Oxygen plasma is effective for removal of surface organic contaminants and surface modification, and hydrogen plasma is capable of reducing metal oxides.

In the present invention, the contaminants and / or oxides on the outermost surface of the insulating substrate are removed by the physical means using the plasma, and the moisture-sensitive thin film and the insulating substrate are separated by the following two action mechanisms. It is thought that the adhesion of is improved.

First, the contaminants and oxides on the outermost layer cause a "weak bou layer" between both interfaces of the moisture sensitive thin film and the insulating substrate.
It acts as a "ndary layer)" and by removing this layer the adhesion becomes stronger.

Secondly, by removing the contaminants and / or oxides on the outermost layer, the wettability of the surface of the insulating substrate is improved, and when the moisture-sensitive thin film-forming monomer is applied, the monomer reaches the pores of the insulating substrate. After reaching and polymerizing, the moisture sensitive thin film roots on the insulating substrate, and the moisture sensitive thin film and the insulating substrate are brought into close contact with each other by the action of "anchor". In the present invention, it is considered that the latter action largely works.

The moisture-sensitive thin film used in the present invention is obtained by coating a monomer having an ethylenically unsaturated reactive group on an insulating substrate by coating, and then polymerizing it by an appropriate means such as ultraviolet irradiation or heating. . Also, this monomer is
It is preferable that the polymer contains a quaternary ammonium salt, and therefore the polymer obtained contains a quaternary ammonium salt in the molecule and is preferably called an ionene polymer. In addition, the quaternary ammonium salt in the present invention is a quaternary ammonium salt in a narrow sense, which is a salt of ammonium having four alkyl groups bonded to nitrogen atoms, and an ammonium type obtained from primary to tertiary amines. Refers to all salt.

When the monomer has one ethylenically unsaturated reactive group (for example, in the case of the formula (2)), the above-mentioned crosslinkable polymer is a side chain type polymer having a conductive point in the side chain, 2 When it has one (for example, in the case of the formula (1)), it becomes a main chain type polymer having a conductive point in the main chain. In particular, when the monomer is bifunctional having two acrylic unsaturated reactive groups, it can be three-dimensionally reacted to form a crosslinked structure and be insoluble in water.

In the moisture-sensitive thin film using the crosslinkable copolymer having such an ionene polymer structure, the quaternary ammonium salt portion contained in the polymer molecule becomes the portion expressing the conductivity, and the quaternary ammonium salt. Counterions of salt are dissociated by moisture in the atmosphere and exhibit ionic conductivity. Humidity is detected by utilizing the phenomenon that the degree of dissociation changes depending on the amount of water in the atmosphere.

The above-mentioned monomers may be selectively used depending on the purpose of use of the humidity sensor, and a copolymer of different types of monomers may be used.

In general, the shape close to the main chain type has an advantage that hysteresis does not occur in the humidity response characteristic, and the shape close to the side chain type has some hysteresis, but the quaternary ammonium which is a conductive expression portion. There is an advantage that it is easy to introduce a large number of salts. In any case, it suffices to properly use the basic characteristics of the humidity sensor such as durability, gas resistance, and hysteresis depending on where the emphasis is placed. Further, the counter ion of the ammonium ion in the ammonium salt can be selected according to the purpose.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The humidity sensor element of the present invention has a pair of electrodes on an insulating substrate so as to face each other with a gap therebetween, and has a moisture sensitive thin film on the gap.

An example of the structure of such a humidity sensor element is shown in FIG. However, the present invention is not limited to this. FIG. 1 is a plan view. As shown in FIG. 1, the humidity sensor element 1 has a pair of comb-shaped electrodes 4 on an insulating substrate 2, and the pair of comb-shaped electrodes 4 are meshed with each other via a gap 5 at a constant distance. It is placed on top. A moisture sensitive thin film 3 is provided on the insulating substrate 2 and the comb-shaped electrode 4 as shown in the figure. Further, an electrode terminal 6 is attached to one end of each of the comb-shaped electrodes 4, and a lead wire 7 is attached to each of the electrode terminals 6 by soldering 8.
Are connected using. Further, as shown in the drawing, a resist film 9 for preventing diffusion of the electrode material is provided.

The gap between the pair of electrodes in the present invention is usually about 100 to 500 μm.

With this structure, an alternating current is preferably applied between both electrodes. The output voltage changes due to a change in resistance or impedance of the humidity sensitive thin film depending on the humidity, and the humidity is detected. The applied voltage is about 12V or less.

Among these, the insulating substrate 2 will be described later, but when explained according to the illustrated example, the electrode 4 is not particularly limited as long as it is usually used, and for example, contains Au or RuO _{2, and the} like. It is possible to use, for example, a low-resistance paste containing glass frit which is screen-printed and sintered at high temperature, if necessary. In the case of an oxide electrode such as RuO ₂ , the functional groups such as hydroxyl groups on the surface are
It contributes to the improvement of the adhesiveness with the moisture sensitive thin film 3. In addition, the electrode terminal 6
Any material may be used as long as it is compatible with the solder 8. For example, Ag-Pd alloy or the like may be used, and these may be printed by a usual method and baked at a high temperature. further,
For example, when Au is used for the electrode 4, as shown in FIG. 1, it is preferable to provide a resist film 9 made of resist or glass for preventing Au diffusion during the soldering process. There is no limitation on the thickness and shape of the resist film 9 as long as it has an effect of preventing Au diffusion during the soldering process.

The insulating substrate having a pair of comb-shaped electrodes used in the present invention, in the state where the comb-shaped electrodes are arranged, is as described above.
The treatment is performed by physical means to remove contaminants and oxides on the outermost surface, and a moisture-sensitive thin film is formed thereon.

The insulating substrate having a pair of comb-shaped electrodes used in the present invention has no chemical reactivity with the moisture sensitive thin film and is not particularly limited as long as it has electrical insulation.
For example, glass, plastic, ceramic or a metal plate coated with insulation is used. Alumina is particularly preferable because it has high mechanical strength, insulation and stability.

The alumina substrate preferably used in the present invention will be described below as an example.

On the surface of the insulating substrate having such a pair of comb-shaped electrodes (hereinafter, comb-shaped electrode substrate), many contaminants, adsorbed gases, and organic substances are adsorbed during preparation and storage, and
The outermost layer of the alumina substrate is covered with the oxide of the substrate itself.

In the present invention, the above-mentioned contaminants, adsorbed gases, adsorbed organic substances, and the like other than oxides taken into the comb-shaped electrode substrate from the outside are collectively referred to as contaminants, and in addition to oxide contaminants. , Including the material of the insulating substrate itself is called an oxide.

More specifically, for example, organic substances drifting in the environment, residues of chemicals used during manufacturing, additives, etc. are attached. These, combined with the oxide of the substrate itself, reduce the wettability of the comb-shaped electrode substrate, so that not only does it not spread even when the monomer liquid for forming a moisture-sensitive thin film is applied, but it also forms a moisture-sensitive thin film after polymerization. Has poor adhesion.

Therefore, in the present invention, the contaminants on the outermost layer and / or the oxides on the outermost layer are removed by the treatment by physical means before the application of the monomer liquid for forming a moisture sensitive thin film.

Taking an alumina substrate as an example, when contaminants are present on the surface, ignoring the pores, the outermost layer is located in a region portion having a depth of about 1 nm from the surface, including the portion. The removal of the surface contaminants and oxides by physical means can be confirmed by the wettability of the surface. In most cases, the contact angle of water is close to 0 °. For removal, in addition to contaminants, the surface layer of the electrode and substrate itself (the area that is about 1 nm deep from the surface of itself)
Is preferably performed for Therefore, it is preferable to remove both contaminants and oxides. However, if the surface of the electrode or the substrate itself is removed too much, it is not preferable because the shape of the electrode and the surface of the substrate are changed.

As the treatment by physical means, flame plasma treatment, UV / ozone treatment, excimer UV treatment,
Although corona treatment, electron beam treatment, laser treatment, sputtering treatment, plasma treatment and the like can be used, plasma treatment is preferable because it does not damage the insulating substrate and is inexpensive. There is also a comb-shaped electrode substrate suitable for UV / ozone treatment because of its low cost, but when it is limited to an alumina substrate, coloring is often seen after the treatment. However, coloring can be prevented by selecting processing conditions.

The plasma treatment preferably used in the present invention will be described. As described in the section of the above-mentioned action, in the present invention, the action of removing the organic matter possessed by the oxygen plasma and the surface modification action, and the action of reducing the metal oxide possessed by the hydrogen plasma are effective, and the oxygen plasma alone, Alternatively, it is preferable to perform treatment of hydrogen plasma after oxygen plasma. Further, from the viewpoint of simplicity, plasma treatment in which an inert gas is introduced is also preferable.

The plasma treatment may be carried out under any of vacuum, inert gas, and atmospheric pressure as long as it is a relatively low-temperature plasma condition that does not damage the comb-shaped electrode substrate. Select according to the conditions.
Among them, the conditions of inert gas and atmospheric pressure are preferable because the apparatus becomes simple, but plasma treatment in which oxygen or hydrogen is introduced as described above in vacuum is general.

Whichever method is used, the power supply frequency is several kHz.
-The plasma generated at several hundred MHz is used, but the output is adjusted appropriately according to the plasma generation conditions. When the comb-shaped electrode substrate is made of alumina, the effect can be obtained by treating the high frequency output in the range of 50 to 1000 W for 2 seconds to 10 minutes.

The comb-shaped electrode substrate subjected to the plasma treatment is next coated with a monomer solution for forming a moisture sensitive thin film. The time until coating is preferably 24 to 96 hours when stored in a vacuum, and within 24 hours immediately after the processing under atmospheric pressure. If the storage condition is poor, the time for which the surface condition can be maintained satisfactorily becomes short, so it is desirable to apply continuously immediately after the plasma treatment.

As a coating method, any method can be used as long as a fixed amount can be coated on the comb-shaped electrode substrate. For example, various methods such as a dipping method, a dropping method, a brush coating method, a gravure printing method, a screen printing method, and a spinner coating method can be used, and it may be selected depending on the process and the use / type of the product. .

After forming the coating film in this manner, 15 to 1
It is dried at a temperature of about 00 ° C. for about 3 to 15 minutes. Here, some monomers are thermally polymerized to form a moisture-sensitive thin film.

As the polymerization method, there is radiation crosslinking in addition to the above thermal method. Cross-linking by irradiation, in particular,
It is preferable to irradiate with ultraviolet rays.

The crosslinking method by irradiation with ultraviolet rays may be carried out according to a known method. Normally, the intensity of UV light irradiated is 8
The irradiation amount may be about 0 mW / cm ² or more and the irradiation amount may be about 200 to 2500 mJ / cm ² . Further, as the ultraviolet ray source, a normal one such as a mercury lamp may be used.

The thickness of the moisture-sensitive thin film thus obtained after crosslinking is preferably about 0.5 to 10 μm, more preferably about 3 to 10 μm. If the film is too thick, the response speed of the electric resistance value of the film to humidity, that is, the response becomes slow, and if the film is too thin, the output particularly in the low humidity region decreases, and the gas resistance also decreases. Not preferable.

The coating liquid is a 1 to 10% (mass percentage) aqueous solution containing a moisture-sensitive thin film-forming monomer in a predetermined ratio, an organic solvent solution such as alcohol, or a mixed solvent solution. At this time, when the above-mentioned copolymer is later cross-linked by irradiation with radiation, preferably ultraviolet rays, a photopolymerization initiator (for example, a water-soluble benzophenone-based compound) is added in an amount of 0.
It is preferable to add about 03 to 0.7% (mass percentage).

In the present invention, the above moisture-sensitive thin film is obtained by polymerizing a monomer having an ethylenically unsaturated reactive group, and further, in addition to the ethylenically unsaturated reactive group, a quaternary ammonium salt. It is preferable that a monomer containing is polymerized.

As such a monomer, a monomer represented by the formula (1) and a monomer represented by the formula (2) are preferable.

The monomer represented by the formula (1) will be described.

[0056]

[Chemical 1]

In the formula (1), A represents a divalent group.
Y _l , Y ₂ , Y ₃ , Y ₄ , Y ₅ and Y ₆ each represent a monovalent group, and may be the same or different, and at least one of them has an ethylenic unsaturated reactivity. A group having a group at the terminal. Y _l , Y ₂ , Y ₃ , Y ₄ , Y ₅ , A
And any 2 of these nitrogen atom (N) side parts
Or more, or any two or more of Y ₄ , Y ₅ , Y ₆ , and B ₀ (provided that they are divalent groups as described later) and a part of these nitrogen atom (N) sides. May be bonded to each other to form a ring with the nitrogen atom (N). X
_l ⁻ and X ₂ ⁻ each represent an anion, and may be the same or different. n ₀ is 1 to 5000, and when n ₀ is 1, B ₀ represents a bond and n ₀ is 2 to
When it is 5000, B ₀ represents a divalent group.

To further explain, in equation (1), Y
_{l to} Y ₆ represent a monovalent group, and at least one of Y _{l to} Y ₆ is a group having an ethylenically unsaturated reactive group at the terminal. Such groups include acryloyloxy group, methacryloyloxy group, acryloylamino group, methacryloylamino group, vinyl group, allyl group, diallylmethyl group, allyloxy group, diacryloylamino group, dimethacryloylamino group and these groups. Examples include introduced groups.

Examples of the group other than the group having an ethylenically unsaturated reactive group represented by Y _{1 to} Y ₆ at the terminal include an alkyl group, an alkenyl group and a halogen atom.
Specific examples of the alkyl group and the alkenyl group include those similar to R ₁ and the like in the formula (1a) and the formula (1b), which are preferable in the formula (1), and are also described below. . Examples of the halogen atom include chlorine, bromine and iodine. Also, any combination of two or more of Y _{l to} Y ₅ , A and some of these, or Y ₄
To Y _6, any two or more thereof from among the B ₀ and some of these when a divalent radical, with the two or more bond to a nitrogen atom (N) to form a ring However, the ring formed is the same as the ring formed by R _{1 and the} like in formula (1a) and formula (1b), and will be described later.

As described above, the monomer represented by the formula (1) may be one having at least one ethylenically unsaturated reactive group, and usually about 2 is preferable.

Further, the monovalent group represented by Y _{2 to} Y ₅ may include a bonding chain of repeating units in the molecular structure represented by the formula (1), and in that case, in the formula (1) The repeating units of may be the same or different.

It should be noted, A in the formula _{(1), B 0, n} 0, X 1 -,
X ₂ ⁻ has the same meaning as formula (1a), formula (1b), A, B, n, X ₁ ⁻ , and X ₂ ⁻ , which are preferable embodiments when n ₀ is 2 to 5000, (1a) and equation (1b) will be described together.

Among the monomers represented by the formula (1),
When n ₀ = 2 to 5000, the formula (1a) and the formula (1b)
The monomer represented by the formula (1) is preferable, and when n ₀ = 1, the monomer represented by the formula (1c) is preferable. First, the formula (1
A) and formula (1b) will be described.

[0064]

[Chemical 2]

[0065]

[Chemical 3]

In the formulas (1a) and (1b), A and B each represent a divalent group.

The divalent group represented by A is preferably an alkylene group, an alkenylene group, an arylene group or a combination thereof, even if they are substituted with an alkyl group such as a hydroxy group or a methyl group, or a carbamoyl group. Good.

The total number of carbon atoms of the alkylene group is preferably 1 to 20, and the number of substituents when the hydroxy group is substituted is 1 to 5
Is preferred.

The total carbon number of the alkenylene group is preferably 2-10.

The total carbon number of the arylene group is preferably 6-20.

The total number of carbon atoms in these combinations is preferably 3-20.

Specifically,-(CH ₂ ) _m- (m = 1 to 2
0 _{integer), - CH 2 CH = CH} -CH 2 -, - CH 2 -
_{CH (OH) -CH 2 - -CH} (CH 3) -CH 2 -CH 2 -, - C 6 H 4 -C 6 H 4
_{-, - C 6 H 4 -CH} (OH) -C 6 H 4 - , and the like as preferred.

The divalent group represented by B includes an alkylene group, an oxy group (-O-) and a carponyl group (-CO).
An alkylene group, an alkenylene group, an arylene group or a combination thereof in which one or more of-) are present are preferable, and these may be substituted with an alkenyl group such as a hydroxy group or a vinyl group.

The total number of carbon atoms of the alkylene group is preferably 1 to 20, and the number of substituents when the hydroxy group is substituted is 1 to 5
Is preferred. The total number of intervening -O- and -CO- groups in the alkylene group is preferably 1-5.

The total carbon number of the alkenylene group is preferably 2-10. The total carbon number of the arylene group is preferably 6-20. In addition, the total number of carbon atoms in the combination of these is 3 to
20 is preferable.

Specifically,-(CH ₂ ) _m- (m = 1 to 2
0 _{integer), - (CH 2) 2} -CH (OH) -CH 2 -,
_{-CH 2 -CH (OH) -CH 2} -, - CH 2 -CH = C
_{H-CH 2 -, - CH} 2 -CH (CH = CH 2) -, -
_{(CH 2 -CH 2 -O) 2} - (CH 2) 2 -, - CH 2 - (C
_{O) -CH 2 -, - CH} 2 -C 6 H 4 -CH 2 - , and the like as preferred.

R ₁ , R ₂ , R ₃ and R ₄ each represent an alkyl group or an alkenyl group.

The alkyl group represented by R _{1 to} R ₄ preferably has 1 to 10 carbon atoms and may have a substituent, but it is preferably unsubstituted. Specifically, a methyl group, an ethyl group, a propyl group, a butyl group and the like are mentioned as preferable ones.

The alkenyl group represented by R _{1 to} R ₄ preferably has 2 to 10 carbon atoms and may have a substituent, but it is preferably unsubstituted. Specifically, a vinyl group, an allyl group, a propenyl group, a butenyl group and the like are preferred.

R ₁ and R ₂ , R ₁ and A or a part of A, R ₂
And A or part of A, R ₃ and R ₄ , R ₃ and A or A
, R ₄ and A or a part of A, R ₁ and R ₃ or R ₄ , or R ₂ and R ₃ or R ₄ may combine with each other to form a ring with the nitrogen atom (N). . As such a ring, a 5-membered or 6-membered, particularly 6-membered, nitrogen-containing heterocycle is preferably mentioned, and a bridged ring may be used.
Examples of such nitrogen-containing heterocycle include pyridine ring, 1,4
-Azabicyclo [2.2.2] octane ring, piperidine ring, piperazine ring, pyrazine ring and the like are preferable, and in some cases, carbamoyl group and the like may be substituted.

In the formula (1a), R ₅ and R ₆ each represent an alkyl group or an alkenyl group. Among them, an alkyl group is preferable, one having 1 to 10 carbon atoms is preferable, and it may have a substituent, but it is preferably unsubstituted, and a methyl group, an ethyl group and the like are preferable. Specific examples of the alkenyl group represented by R ₅ and R ₆ are the same as those in R _{1 to} R ₄ .

In the formulas (1a) and (1b), L represents a divalent group. Preferred as L in formula (1a) are —COO (CH ₂ ) ₂ — and —CONH (CH ₂ ) _{3
-, - (CH 2) m} - (m is an integer of 1 to 20), and the like. As the preferred of L in the formula _{(1b), -OCH 2 CH 2} -, - (CH 2) m - (m is 1
Integer of _{20), - COO (CH 2} ) 2 -, - COOCH 2
_{CH (OH) CH 2 -,} - CH 2 -C 6 H 4 - (p- or m-) and the like.

In the formula (1a), R ₅ , R ₆ and L are appropriately bonded by a combination of two or three of them to form a pyridine ring or the like together with the nitrogen atom (N). Good.

In the formulas (1a) and (1b), R represents a hydrogen atom or an alkyl group, and a hydrogen atom and a methyl group are particularly preferable.

[0085] Formula (1a), in the formula (1b), X ₁ ^-,
X ₂ ⁻ represents an anion, which is preferably a halide ion, and specifically may be a chloride ion, a bromide ion, an iodide ion or the like, but a chloride ion or a bromide ion is preferable, and a chloride ion is particularly preferable. preferable. These X
₁ ⁻ and X ₂ ⁻ are usually the same, but may be different from each other. In the formula (1b), X ₃ ⁻ represents an anion, and the two X ₃ ⁻ in the formula (1b) use the same symbols according to the synthetic scheme described later, and although they are usually the same, It may be different depending on the case. Specific examples and preferable ones are the same as those for X ₁ ⁻ and X ₂ ⁻ . Further, X ₁ ⁻ , X ₂ ⁻ , and X ₃ ⁻ are usually the same. n is 2 to 50
Represents the number 00.

The monomer represented by the formula (1), the formula (1a) or the formula (1b) should be called a polymer having a predetermined repeating unit, and its number average molecular weight M _n is 1000 to 1.
It is about, 000,000.

The monomer of formula (1a) is synthesized according to the scheme shown below. The case where X ₁ ⁻ and X ₂ ⁻ are halide ions is taken as an example, and the symbols in the scheme are as defined above.

[0088]

[Chemical 4]

First, an intermediate polymer I having a quaternary ammonium salt and having a halogen terminal group is obtained from the reaction of a diamine compound and a dihalogen compound. In this case, the dihalogen compound is 1.1 times the molar amount of the diamine compound.
The reaction may be performed under the condition that the molar amount is 2.0 times. Further, in order to ensure that the end group of the intermediate polymer I is halogen, the dihalogen compound may be added in two portions,
In this case, the first addition amount is 1 with respect to the diamine compound.
The molar amount may be about 1.3 to 1.3 times, and the balance may be added at the second time.

The reaction at this time is carried out at a reflux temperature or a temperature of about 100 ° C. for about 5 to 100 hours in a non-aqueous solvent such as methanol, isopropanol, methoxyethanol or 2-ethoxyethanol.

Next, the compound A having an ethylenically unsaturated reactive group is reacted with the intermediate polymer I to introduce an ethylenically unsaturated reactive group at both ends of the intermediate polymer I to obtain the compound represented by the formula (1a).
To obtain the monomer. The reaction in this case may be carried out after the above reaction, and the compound A having an ethylenically unsaturated reactive group in the solution in an approximately equimolar amount to the dihalogen compound.
Is added at a temperature of about 15 to 100 ° C. for 10 to 150
React for about an hour.

Then, the reaction solution is added dropwise to a solvent such as acetone or ethyl acetate to form a precipitate, which is collected by filtration for purification by precipitation to obtain the desired product.

On the other hand, the monomer of formula (1b) is synthesized according to the scheme shown below. The case where X ₁ ⁻ and X ₂ ⁻ are halide ions is taken as an example, and the symbols in the scheme have the same meanings as above. Note that X ₃ ^{− is} also preferably a halide ion.

[0094]

[Chemical 5]

First, an intermediate polymer II having a quaternary ammonium salt and having an amino terminal terminal group is obtained from the reaction of a diamine compound and a dihalogen compound. In this case, the diamine compound is 1.1 times the molar amount of the dihalogen compound to 2.
The reaction may be performed under the condition that the molar amount is 0 times. Other reaction conditions and the like are the same as in the case of obtaining the above-mentioned intermediate polymer I, and the method for surely making the terminal group an amino group may be carried out according to the above.

Then, the compound B having an ethylenically unsaturated reactive group is reacted with the intermediate polymer II to introduce the ethylenically unsaturated reactive groups at both terminals of the intermediate polymer II to prepare the monomer of the formula (1b). To get The reaction in this case may be carried out in the same manner as the monomer of the above formula (1a).

The monomers represented by the formulas (1a) and (1b) are obtained by reacting a diamine compound with a dihalogen compound, and if the reaction according to the above scheme is possible, the diamine compound used. The dihalogen compound and the dihalogen compound may be any compounds and are not particularly limited. In addition, these monomers and intermediate polymers are usually obtained as a mixture of an oligomer having a degree of polymerization n of about 2 to 20 and a polymer having a degree of polymerization n of more than 20.

Preferred examples of the diamine compound are shown below.

[0099]

[Chemical 6]

[0100]

[Chemical 7]

[0101]

[Chemical 8]

Preferred examples of the dihalogen compound are shown below.

[0103]

[Chemical 9]

[0104]

[Chemical 10]

In the above, X is a halogen atom, but chlorine atom and bromine atom are preferable.

Examples of intermediate polymers of the monomers of the formulas (1a) and (1b) are shown below as the polymers obtained from the combination of the diamine compound and the dihalogen compound. The numerical value in parentheses indicates the molar ratio.

(1) A-16 / B-10 (50/50)
Polymer (2) A-8 / B-12 / B-10 (50/48/2) obtained from the combination of
Polymer (3) A-8 / B-13 / B-10 (50/48/2) obtained from the combination of
Polymer (4) A-8 / B-15 / B-10 (50/48/2) obtained from the combination of
Polymer obtained from the combination of (5) A-16 / B-2 (50/50) Polymer obtained from the combination of (6) A-7 / B-10 (50/50) obtained from the combination of Polymer (8) A-9 / B-10 (50/50) obtained from combination (7) A-2 / B-10 (50/50) of polymer (9) A- obtained from combination of (9) Polymer (10) A-3 / A-8 / B-10 (2/48/50) obtained from a combination of 16 / B-9 (50/50)
Polymers obtained from combinations of

(11) A-14 / A-16 / B-17
Polymer (12) A-11 / B-16 obtained from the combination (49/1/50) Polymer (13) A-6 / B-4 / B-15 obtained from the combination (50/50) (50/47/3)
Polymer obtained from the combination of (14) A-11 / B-6 (50/50) Polymer obtained from the combination of (15) A-13 / B-3 (50/50) obtained from the combination of Polymer (17) obtained from the combination of A-10 / B-15 (50/50) (17) Polymer obtained from the combination of A-15 / B-16 (50/50) (18) A- Polymer (19) A-10 / B-12 / B-10 (50/48 /) obtained from the combination of 4 / B-10 (50/50).
Polymer obtained from the combination of 2) (20) Polymer obtained from the combination of A-8 / B-2 (50/50)

(21) A-7 / A-16 / B-10 (1
5/35/50) polymer (22) A-8 / A-16 / B-10 (15/35/5)
Polymer (23) A-9 / A-16 / B-10 (15/35/5) obtained from the combination of
0) the polymer (24) A-10 / A-16 / B-10 (15/35 /
Polymer (25) A-8 / B-13 obtained from the combination of (50) Polymer (26) A-8 / A-10 / B-13 obtained from the combination of (50/50)
Polymer (27) A-8 / B-13 / B-10 (50/40/1) obtained from the combination of (15/35/50)
Polymer (28) A-8 / B-13 / B-2 (50/40/1) obtained from the combination of
0) polymer (29) A-9 / B-13 (50/50) polymer (30) A-8 / A-9 / B-13 (2)
5/25/50)

(31) A-9 / A-10 / B-13 (2
5/25/50) Polymer (32) A-19 / B-15 (50/50) Polymer (33) A-15 / B-9 (50/50) (34) Polymer obtained from the combination of A-15 / B-15 (50/50)

The compounds A and B used when introducing the ethylenically unsaturated reactive group into both ends of the intermediate polymers I and II include acryloyloxy group, methacryloyloxy group, acryloylamino group, methacryloylamino group,
There is no particular limitation as long as it is a compound having an ethylenically unsaturated reactive group such as a vinyl group, an allyl group, a diallylmethyl group, an allyloxy group, a diacryloylamino group and a dimethacryloylamino group. In the case of a polymer having an ethylenically unsaturated reactive group at the terminal at the stage of producing the intermediate polymers I and II [eg (10), (11), (13)], it is used as a monomer of the present invention as it is. Can be used.

Examples of the compound A preferably used in combination with the intermediate polymer I include the following.

[0113]

[Chemical 11]

On the other hand, the compound B preferably used in combination with the intermediate polymer II includes the following.

[0115]

[Chemical 12]

In the above, X is a halogen atom,
Chlorine atom and bromine atom are preferred.

Next, when n ₀ = 1, the equation (1)
The monomer of the formula (1c) which is a preferable embodiment of the monomer of

The formula (1c) will be described.

[0119]

[Chemical 13]

In the formula (1c), A ₁₁ represents a divalent group. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent a hydrogen atom or an alkyl group, and may be the same or different. Y ₁₁ and Y ₁₂ each represent a monovalent group having an ethylenically unsaturated reactive group at the terminal and may be the same or different. R _{11 to} R ₁₄ , Y ₁₁ , Y ₁₂ , A
Any two or more of ₁₁ and a part of these on the nitrogen atom (N) side may be bonded to each other to form a ring together with the nitrogen atom (N). X ₁₁ ⁻ and X ₁₂ ⁻ each represent an anion, and may be the same or different.

The divalent group represented by A ₁₁ is preferably an alkylene group, an alkenylene group, an arylene group or a combination thereof, and these are alkyl groups such as methyl group,
Alternatively, a carbamoyl group or the like may be substituted.

The total number of carbon atoms in the alkylene group is preferably 1-20.

The total carbon number of the alkenylene group is preferably 2-10.

The total carbon number of the arylene group is preferably 6-20.

The total carbon number in the case of these combinations is preferably 3 to 20.

Specifically,-(CH ₂ ) _m- (m = 1 to 2
0 _{integer), - CH 2 CH = CH} -CH 2 -, - CH (C
_{H 3) -CH 2 -CH 2 -} , - C 6 H 4 -C 6 H 4 - or the like have, in particular _{- (CH 2) m - (} m = 1~20 integer) are preferred.

Y₁₁, Y₁₂Ethylenic unsaturation represented by
As the monovalent group having a reactive group at the terminal, an acrylic type
Preferred are those having an acryloyloxyalkyl group or meta.
Acryloyloxyalkyl group, acryloylaminoal
A group having a kill group or a methacryloylaminoalkyl group
Yes, preferably acrylic acid or methacrylic acid
Ruylene ester group, or acrylic acid or methacryl
Examples include alkylene amide amide groups. Y₁₁, Y₁₂
It is preferable that the total number of carbon atoms is 4 to 8. Y ₁₁And Y₁₂
Are usually the same, but may be different from each other.

The alkyl group represented by R _{11 to} R ₁₄ is generally unsubstituted, but may have a substituent and has a total carbon number of 1 to 5. preferable. Specific examples thereof include a methyl group, an ethyl group and a propyl group, and a methyl group is particularly preferable. As R _{11 to} R ₁₄ , at least one of R ₁₁ and R ₁₂ is an alkyl group,
And it is preferable that at least one of R ₁₃ and R ₁₄ is an alkyl group, and it is also preferable that all of R _{11 to} R ₁₄ are alkyl groups. When a plurality of alkyl groups are present, they are usually the same. , Each may be different.

Any combination of two or more of R _{11 to} R ₁₄ , Y ₁₁ , Y ₁₂ , A ₁₁ and a part (N side) thereof may be combined with two or more thereof to form a nitrogen atom. A ring may be formed with the atom (N), but it is preferable not to form a ring.

The anion represented by X ₁₁ ⁻ and X ₁₂ ⁻ is particularly preferably a halide ion, and specifically, it may be a chloride ion, a bromide ion, an iodide ion or the like. Bromide ions are preferred, and chloride ions are particularly preferred. X ₁₁ ⁻ and X ₁₂ ⁻ are usually the same, but may be different from each other.

The monomer represented by the formula (1c) is, as described above, a monomer having an acrylic unsaturated reactive group at both ends.
It is preferably a functional monomer.

The monomer represented by the formula (1c) used in the present invention is obtained as follows. Specifically, the monomer of formula (1c) is synthesized according to the scheme shown below.

[0133]

[Chemical 14]

The above Y ₁₁ , Y ₁₂ , R _{11 to} R ₁₄ , A
₁₁ has the same meaning as in formula (1c). Also, X ₁₁ , X
_For example, ₁₂ is a halogen atom.

First, the acrylic amine compound (a-1,
From the reaction of a-2) with the dihalogen compound (b), a monomer of the formula (1c) having a quaternary ammonium salt and having both terminal groups an acrylic unsaturated reactive group is obtained. At this time, the amount of the acrylic amine compound added may be at least twice the molar amount of the dihalogen compound, particularly 2.0 to 3.0 times.

The reaction at this time is carried out by stirring in an aprotic polar solvent such as acetonitrile or dioxane at about 50 ° C. for several days. When refluxed in an alcohol such as methanol, isopropanol, methoxyethanol, or 2-ethoxyethanol as a solvent, transesterification occurs, and the desired diacrylic quaternary ammonium salt cannot be obtained. Therefore, an alcohol-based solvent that may cause a transesterification reaction is not suitable.

After completion of the reaction, acetone or the like is added to precipitate the desired quaternary ammonium salt, and the obtained white precipitate is filtered. After washing with acetone, it is dried to obtain the desired product.

The compound used for introducing an ethylenically unsaturated reactive group, preferably an acrylic unsaturated reactive group, into both terminals of the monomer of the formula (1c) is an acryloyloxy group, a methacryloyloxy group or an acryloyl group. There is no particular limitation as long as it is a compound having an ethylenically unsaturated reactive group such as an amino group, a methacryloylamino group, a diacryloylamino group, and a dimethacryloylamino group, preferably an acrylic unsaturated reactive group, acrylic acid or methacrylic acid. Acid alkylaminoethyl ester, acrylic acid or methacrylic acid alkylaminoethylamide, acrylic acid or methacrylic acid dialkylaminoethyl ester or acrylic acid or methacrylic acid dialkylaminoethylamide are preferred, and these are also included in the following specific examples. Show.

Acrylic acid methyl aminoethyl ester Acrylic acid methylaminopropylamide Methacrylic acid methyl aminoethyl ester Methacrylic acid methylaminoethylamide Methacrylic acid methyl aminopropyl ester Methacrylic acid methylaminopropylamide Methacrylic acid methyl aminobutyl ester Methacrylic acid methyl aminopentyl ester Methacrylic acid methylaminohexane ester Methyl methacrylate amino octyl ester Methyl methacrylate amino octyl amide Acrylic acid dimethylaminoethyl ester Acrylic acid dimethylaminopropylamide Methacrylic acid dimelaminoethyl ester Methacrylic acid dimethylaminoethylamide Methacrylic acid dimethylaminopropyl ester Methacrylic acid dimethylaminopropylamide Methacrylic acid dimethylaminobutyl ester Methacrylic acid dimethylaminopentyl ester Methacrylic acid dimethylaminohexane ester Methacrylic acid dimethylaminooctyl ester Methacrylic acid dimethylaminooctylamide Such

Specific examples of the dihalogen compound to be reacted therewith are shown below.

1,3-dichloropropane, 1,4-dichlorobutane, 1,5-dichloropentane, 1,6-dichlorohexane, 1,8-dichlorooctane, 1,10-
Dichlorodecane, 1,12-dichlorododecane, 1,3
-Dibromopropane, 1,4-dibromobutane, 1,5
-Dibromopentane, 1,6-dibromohexane, 1,
8-dibromooctane, 1,10-dibromodecane,
1,12-dibromododecane etc.

There are no particular restrictions on the molecular weight of the monomer of formula (1c), but when the preferable A _{11 and the} like are taken into consideration, it is usually 6
It is 50 or less. The lower limit is not particularly limited, but is usually 3
It is about 70.

Next, the monomer represented by the formula (2) will be described.

[0144]

[Chemical 15]

In the formula (2), A ₂₁ represents a divalent group. R ₂₁ , R ₂₂ and R ₂₃ each represent an alkyl group and may be the same or different. Y ₂₁ represents a monovalent group having an ethylenically unsaturated reactive group at the terminal. X ^- ₂₁ represents an anion.

The divalent group represented by A ₂₁ is preferably an alkylene group, an alkenylene group, an arylene group (for example, a phenylene group), a carbonyl group, a carbonyloxy group or a combination thereof, and these are alkyl groups such as a methyl group. Or a carbamoyl group or the like may be substituted.

The total number of carbon atoms in the alkylene group is preferably 1-20. The alkenylene group preferably has 2 to 10 total carbon atoms. The total carbon number of the arylene group is preferably 6-20.

The total number of carbon atoms in the combination of these is preferably 3 to 20. Specifically, - (CH ₂₎ m-
(M = 1 to 20 _{integer), - CH 2 CH = CH} -CH
_{2 -, - CH (CH 3} ) -CH 2 -CH 2 -, - C 6 H 4 -C
₆ H ₄ — and the like, and — (CH ₂ ) m — (m = 1 to 20 is an integer) is particularly preferable.

The monovalent group having an ethylenically unsaturated reactive group represented by Y ₂₁ at its terminal is preferably a vinyl type or acrylic type, and particularly an acrylic type acryloyloxy group, methacryloyloxy group or acryloylamino group. Group, a group having a methacryloylamino group, preferably an acrylic acid or methacrylic acid alkylene ester group, or an acrylic acid or methacrylic acid alkyleneamide group.

The alkyl group represented by R _{21 to} R ₂₃ is generally unsubstituted, but may have a substituent and the total number of carbon atoms is 1 to 5. preferable. Specific examples thereof include a methyl group, an ethyl group and a propyl group, and a methyl group is particularly preferable. R _{21 to} R ₂₃ are usually the same, but may be different from each other.

Further, any two or more of R _{21 to} R ₂₃ , Y ₂₁ , A ₂₁ and a part (N side) thereof may be combined to form a nitrogen atom (N ) May form a ring, but it is preferable not to form a ring.

The anion represented by X ^- ₂₁ is particularly preferably a halide ion, and specifically, it may be a chloride ion, a bromide ion, an iodide ion or the like.
Chloride ion and bromide ion are preferable, and chloride ion is particularly preferable.

The monomer represented by the formula (2) is preferably a monofunctional monomer having an acrylic unsaturated reactive group as described above.

The monomer represented by the formula (2) used in the present invention is obtained as follows. Specifically, the monomer of formula (2) is synthesized according to a monomer as shown below.

[0155]

[Chemical 16]

The above Y ₂₁ , A ₂₁ , R _{21 to} R ₂₃ are
It has the same meaning as the formula (2). Also, the case where X ₂₁ is a halogen atom is taken as an example.

First, from the reaction of the acrylic amine compound (a) with the monohalogen compound (b-1), a monomer of the formula (2) having a quaternary ammonium salt and an end group of which is an acrylic unsaturated group. To get At this time, the addition amount of the acrylic amine compound may be approximately equimolar with respect to the dihalogen compound, particularly 0.95 to 1 times.

The reaction at this time is carried out by stirring in an aprotic polar solvent such as acetonitrile or dioxane at about 50 to 70 ° C. for 96 hours. When refluxed in an alcohol such as methanol, isopropanol, methoxyethanol, 2-ethoxyethanol, etc. as a solvent, transesterification occurs and the desired acrylic quaternary ammonium salt cannot be obtained. Therefore, an alcohol-based solvent that may cause a transesterification reaction is not suitable.

After completion of the reaction, acetone or the like is added to precipitate the desired quaternary ammonium salt, and the obtained white precipitate is filtered. After washing with acetone, it is dried to obtain the desired product.

The compound used for introducing an ethylenically unsaturated reactive group, preferably an acrylic unsaturated reactive group, into the terminal of the monomer of formula (2) is an acryloyloxy group, a methacryloyloxy group or an acryloylamino group. Group, a methacryloylamino group, a diacryloylamino group, a dimethacryloylamino group, and the like are not particularly limited as long as they are compounds having an ethylenically unsaturated reactive group, preferably an acrylic unsaturated reactive group, acrylic acid or methacrylic acid. Dialkylaminoethyl ester or acrylic acid or methacrylic acid dialkylaminoethylamide is suitable, and specific examples thereof are also shown below.

Acrylic acid dimethylaminoethyl ester Acrylic acid dimethylaminopropylamide Methacrylic acid dimethylaminoethyl ester Methacrylic acid dimethylaminoethylamide Methacrylic acid dimethylaminopropyl ester Methacrylic acid dimethylaminopropylamide Methacrylic acid dimethylaminobutyl ester Methacrylic acid dimethylaminopentyl ester Methacrylic acid dimethylaminohexane ester Methacrylic acid dimethylaminooctyl ester Methacrylic acid dimethylaminooctylamide Such

Specific examples of the monohalogen compound to be reacted therewith are shown below.

Chloropropane, chlorobutane, chloropentane, chlorohexane, chlorooctane, chlorodecane, chlorododecane, bromopropane, dibromobutane, dibromopentane, bromohexane, bromooctane, bromodecane, bromododecane, etc.

The moisture-sensitive thin film of the present invention has the formula (1),
It is formed as described above by using one kind or two kinds or more of the monomers (2). In case of 2 or more types,
A combination of monomers of formula (1) or formula (2) or a combination of monomers of formula (1) and formula (2) may be used.

Specifically, depending on the intended device characteristics, the main chain type or a type close thereto, or, conversely, the side chain type or a type close to this, or the main chain or side The number of carbon atoms in the chain, the type of counterion, etc. may be selected.

In the present invention, it is possible to obtain sufficient adhesion to the moisture-sensitive thin film by treatment with a physical means, and it is not always necessary, but an acrylic monomer having an alkoxysilyl group (for example, acrylic monomer). It can also be used in combination with a system silane coupling agent). in this case,
The moisture-sensitive thin film may be formed by applying an acrylic monomer having an alkoxysilyl group to the comb-shaped electrode substrate after the treatment, and the acrylic-type monomer having an alkoxysilyl group may be contained in the moisture-sensitive thin film-forming monomer coating solution. May be.

Further, in the present invention, a water-repellent film may be provided on the moisture-sensitive thin film in order to prevent the influence of water droplets adhering to it and to perform a quick and accurate humidity measurement.

[0168]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention together with comparative examples.

<Example 1> N, N, N ', N'-tetramethyldiamino-1,12-dodecane 6.30 g (3
6.6 mmol) and 9.12 g of 1,12-dichlorododecane
(40.2 mmol) at 110 ° C. in 23 g of methanol
React for 48 hours and reprecipitate with acetone to 6.04 g
A white precipitate of was obtained. Subsequently, 5.07 g of a white precipitate and 2.98 g of dimethylaminopropyl methacrylamide were reacted in methanol at 90 ° C. for 24 hours, and 2.47 g of a pale yellow precipitate was obtained by reverse reprecipitation operation in acetone. The number average molecular weight was 2734. This substance corresponds to the monomer of formula (1a).

10 ml of a 5 (mass percentage) ethyl cellosolve solution of the monomer of the formula (1a) was prepared, and 0.2% (mass percentage) KAYACURE ABQ (manufactured by Nippon Kayaku Co., Ltd.) was added as a polymerization initiator. It was used as a monomer liquid for forming a moisture-sensitive thin film. The liquid was stored at 4 ° C.

Next, the humidity sensor element 1 as shown in FIG.
Assembled. A porous ceramic substrate made of alumina was used as the insulating substrate 2, and the electrode 4 was a comb-shaped electrode obtained by screen-printing a paste containing RuO ₂ and glass frit and firing it at a high temperature. The gap between the electrodes 4 was about 225 μm.

The comb-shaped electrode substrate was placed in 100 ml of isopropyl alcohol, immersed for 10 minutes for cleaning, and then left to dry.

The plasma treatment was performed using a plasma dry cleaner PDC200 type manufactured by Yamato Scientific. 100 processing samples were put into the apparatus, and a vacuum state was obtained by using a vacuum pump EC-403 (manufactured by ULVAC) for 10 minutes. The flow rate of oxygen gas is 300 sccm (0.51Pa ・
m ³ · s ^-1 ), keep the vacuum to 55Pa,
Plasma was generated at an RF output of 700 W and processed for 1 minute. The distance between the electrodes at this time is 10 cm.

Immediately after the treatment, 2.75 μl of the moisture-sensitive thin film-forming monomer liquid was applied to each device using a dispenser. A coating film was prepared by leaving it to stand at 25 ° C. for 15 minutes and drying it. Next, this coating film was irradiated with ultraviolet rays for 1 minute in a nitrogen atmosphere to be polymerized to obtain a moisture-sensitive thin film. At this time, the irradiation amount of ultraviolet rays was 1000 mJ / cm ² , and the film thickness of the moisture-sensitive thin film was 5 μm.

The humidity sensor element thus obtained was evaluated for output characteristics and tested for water resistance.

The output characteristic was evaluated by using a shunt type humidity generator (model SRH-1, manufactured by Shinei Co., Ltd.) by incorporating a humidity sensor in the circuit described in JP-A-2-123843. The humidity sensor element incorporated in the circuit is installed in the shunt type humidity generator, and the relative humidity is changed from the low humidity side to the high humidity side at 25 ° C. and then from the high humidity side to the low humidity side. 5% RH, 10% RH in each process,
20% RH, 30% RH, 40% RH, 50% RH, 6
0% RH, 70% RH, 80% RH, 90% RH, 95
The output voltage was measured when the humidity sensor element was left for 30 minutes under each humidity condition of% RH. The obtained results are shown in FIG.

In the water resistance test, after measuring the output voltage as described above, the humidity sensor element was immersed in distilled water for 1 minute and dried in the atmosphere, and the output voltage was measured again. Then, the same sensor element was immersed in distilled water for 10 minutes,
30 minutes, 60 minutes and 10% RH,
The output voltage at 30% RH, 50% RH, 80% RH, 90% RH was measured and compared. The obtained results are shown in FIG.

As can be seen from FIG. 2, no hysteresis was observed and a good response curve was shown. Further, it was found from FIG. 3 that the water resistance was excellent.

Further, a gas resistance test was conducted. Gas resistance measures the output value for each relative humidity of the humidity sensor,
Confirm the linearity, then while flowing nitrogen dioxide gas, hydrogen chloride gas, ammonia gas, sulfur dioxide gas, chlorine gas, and hydrogen sulfide gas at a concentration of 5 ppm,
After leaving for 100 hours under the conditions of a temperature of 40 ° C. and a humidity of 70 ° C. to 80% RH, the humidity sensor output value (% RH) for each set humidity (% RH) is measured, and the rate of change (% R
The maximum value of H) was determined. As a result, there is some variation depending on the type of gas, but in all cases, the rate of change is -5 to +.
It was within the range of 5% and the gas resistance was good.

Example 2 9.63 g (67.2 mmol) of acrylic acid methylaminoethyl ester and 3.79 g (33.6 mmol) of 1,3-dichloropropane were reacted with 20 ml of acetonitrile at 60 ° C. for 128 hours. Re-precipitation with acetone gave 5.131 g of a white precipitate.
This substance corresponds to the monomer of formula (1c).

10 ml of a monomer liquid for forming a moisture-sensitive thin film having the same composition ratio as in Example 1 was prepared.

The plasma treatment was performed using an atmospheric pressure plasma cleaning device manufactured by Matsushita Electric Works Machine and Vision. After irradiation with oxygen plasma at an output of 700 W, irradiation distance of 5 mm, and head moving speed of 10 mm / sec, hydrogen plasma was subsequently irradiated under the same conditions for processing.

Thereafter, a moisture sensitive thin film was formed in the same manner as in Example 1 to obtain a humidity sensor element.

The evaluation of the output characteristics and the water resistance test of the thus obtained humidity sensor element were performed in the same manner as in Example 1. The measurement results of the obtained output characteristics are shown in FIG. 4, and the measurement results of the water resistance test are shown in FIG.

It is understood from FIGS. 4 and 5 that excellent humidity response characteristics and water resistance can be obtained.

A gas resistance test was conducted in the same manner as in Example 1, but the rate of change was in the range of -5 to + 5%, and there was no problem in gas resistance.

<Example 3> 8.52 g of dimethylaminopropyl methacrylamide and n-propyl chloride 7.5
8 g was reacted in methanol at 70 ° C. for 24 hours, and 13.28 g of a white precipitate was obtained by reprecipitating with acetone. This substance corresponds to the monomer of formula (2).

A moisture-sensitive thin film-forming monomer solution was prepared from this substance in the same manner as in Example 1, and the moisture-sensitive thin film was formed after treatment under the plasma treatment conditions of Example 1 to obtain a humidity sensor element. It was

The evaluation of the output characteristics and the water resistance test of the thus obtained humidity sensor element were carried out in the same manner as in Example 1. The measurement results of the obtained output characteristics are shown in FIG. 6, and the measurement results of the water resistance test are shown in FIG.

Although there is some hysteresis in FIG. 6,
As is clear from FIG. 7, the water resistance is good.

A gas resistance test was conducted in the same manner as in Example 1, but the rate of change was in the range of -5 to + 5%, and there was no problem in gas resistance.

<Embodiment 4> The plasma treatment time is set to 10
A humidity sensor element was prepared in the same manner as in Example 1 except that the comb-shaped electrode substrate after the plasma treatment was vacuum-stored in a desiccator for 24 hours.

The evaluation of the output characteristics and the water resistance test of the thus obtained humidity sensor element were performed in the same manner as in Example 1. The measurement results of the obtained output characteristics are shown in FIG. 8, and the measurement results of the water resistance test are shown in FIG.

In FIG. 8, some hysteresis is observed, but as is clear from FIG. 9, the water resistance is good.

A gas resistance test was conducted in the same manner as in Example 1, but the rate of change was in the range of -5 to + 5%, and there was no problem in gas resistance.

<Embodiment 5> A humidity sensor was prepared in the same manner as in Embodiment 1 except that the condition of plasma treatment was Ar gas flow rate of 15 sccm (0.0255 Pa · m ³ · s ⁻¹ ) and the treatment time was 2 minutes. A device was created.

The evaluation of the output characteristics and the water resistance test of the humidity sensor element thus obtained were performed in the same manner as in Example 1. FIG. 10 shows the measurement results of the obtained output characteristics, and FIG. 11 shows the measurement results of the water resistance test.

As shown in FIG. 10, the output characteristics are those of the first embodiment.
Although a property almost equivalent to that obtained was obtained, a water resistance test showed that the water resistance was slightly lowered as shown in FIG.

A gas resistance test was conducted in the same manner as in Example 1, but the rate of change was in the range of -5 to + 5%, and there was no problem in gas resistance.

<Example 6> Instead of plasma treatment, U was used.
A humidity sensor element was prepared in the same manner as in Example 1 except that V / ozone treatment was performed.

UV ozone treatment is performed by Nippon Laser Denshi U
V ozone cleaner NL-UV252 was used for 10 minutes under the condition of 4.5W × 2.

The evaluation of the output characteristics and the water resistance test of the thus obtained humidity sensor element were performed in the same manner as in Example 1. The measurement results of the obtained output characteristics are shown in FIG. 12, and the measurement results of the water resistance test are shown in FIG.

Although the output characteristics and the water resistance were almost the same as those in Example 1, the alumina substrate was colored in pale yellow.

A gas resistance test was conducted in the same manner as in Example 1, but the rate of change was in the range of -5 to + 5%, and there was no problem in gas resistance.

Comparative Example 1 A comb-shaped electrode substrate was replaced with 100 ml of isopropyl alcohol in preparation of a humidity sensor element.
After immersing in ultrasonic waves for 10 minutes while immersing it in ultrasonic waves to wash, it was left to dry. This operation was repeated 3 times.

This comb-shaped electrode substrate was coated with the same moisture-sensitive thin film forming monomer solution as in Example 1 without plasma treatment, and then a humidity sensor element was prepared in the same manner as in Example 1.

The evaluation of the output characteristics and the water resistance test of the humidity sensor element thus obtained were performed in the same manner as in Example 1. The measurement results of the obtained output characteristics are shown in FIG. 14, and the measurement results of the water resistance test are shown in FIG.

As shown in FIG. 14, the output characteristics are those of the first embodiment.
Although a property almost equivalent to that obtained was obtained, a water resistance test showed that the water resistance was lost as shown in FIG. There was no problem with gas resistance.

[0209]

According to the present invention, it is possible to easily manufacture a humidity sensor element having excellent water resistance, little influence of gas, excellent solvent resistance, and stable output characteristics in a wide humidity range. That is, since the substrate is subjected to the treatment by physical means, there is almost no dependence on the substrate material and the treatment operation is simple.

[Brief description of drawings]

FIG. 1 is a plan view showing one configuration example of a humidity sensor element of the present invention.

2 is a graph showing measurement results of output characteristics of the humidity sensor element obtained in Example 1. FIG.

FIG. 3 is a graph showing measurement results of a water resistance test of the humidity sensor element obtained in Example 1.

FIG. 4 is a graph showing measurement results of output characteristics of the humidity sensor element obtained in Example 2.

FIG. 5 is a graph showing measurement results of a water resistance test of the humidity sensor element obtained in Example 2.

FIG. 6 is a graph showing measurement results of output characteristics of the humidity sensor element of Example 3.

FIG. 7 is a graph showing measurement results of a water resistance test of the humidity sensor element obtained in Example 3.

FIG. 8 is a graph showing measurement results of output characteristics of the humidity sensor element of Example 4.

FIG. 9 is a graph showing measurement results of a water resistance test of the humidity sensor element obtained in Example 4.

FIG. 10 is a graph showing the measurement results of the output characteristics of the humidity sensor element obtained in Example 5.

FIG. 11 is a graph showing measurement results of a water resistance test of the humidity sensor element obtained in Example 5.

FIG. 12 is a graph showing measurement results of output characteristics of the humidity sensor element of Example 6.

FIG. 13 is a graph showing measurement results of a water resistance test of the humidity sensor element obtained in Example 6.

FIG. 14 is a graph showing measurement results of output characteristics of the humidity sensor element obtained in Comparative Example 1.

FIG. 15 is a graph showing measurement results of a water resistance test of the humidity sensor element obtained in Comparative Example 1.

[Explanation of symbols]

1 Humidity sensor element 2 insulating substrate 3 moisture sensitive thin film 4 electrodes 5 gap 6 electrode terminals 7 lead wire 8 solder 9 Resist film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08F 20/34 C08F 20/34 20/60 20/60 F term (reference) 2G046 AA09 BA01 BA09 BB02 BC04 EA02 EA04 FA01 FA02 4J011 AA05 CA02 CA06 CC09 CC10 4J100 AB15P AL08P AL66P AM21P AM23P BA03P BA31P BA32P CA03 CA04 CA05 JA24 JA43

Claims (4)

[Claims] 1. A method of manufacturing a humidity sensor, comprising a pair of electrodes on an insulating substrate so as to face each other via a gap, and a moisture sensitive thin film on the gap. Alternatively, the oxide is removed by physical means, and then a monomer having an ethylenically unsaturated reactive group is applied on the insulating substrate, and then the monomer is polymerized on the insulating substrate to form a moisture-sensitive thin film. Method for manufacturing humidity sensor element. 2. The method for manufacturing a humidity sensor element according to claim 1, wherein the physical means is plasma surface treatment. 3. The monomer having an ethylenically unsaturated reactive group contains a quaternary ammonium salt.
Of manufacturing humidity sensor element of. 4. A humidity sensor having a pair of electrodes facing each other with a gap on an insulating substrate and having a moisture sensitive thin film on the gap, wherein the insulating substrate is a contaminant and / or an outermost layer. A humidity sensor element, which is an insulating substrate from which oxides have been removed by physical means, wherein the moisture-sensitive thin film contains a polymer of a monomer having an ethylenically unsaturated reactive group.