JP2000193625A - Humidity-sensitive element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a humidity-sensitive element capable of detecting the humidity below a specific percentage RH, particularly in a specific percentage RH range, with a DC current by forming the humidity-sensitive element with a hygroscopic polymer, which is polymerized with polyether amine having two or more amino groups and an epoxy compound having two or more epoxy groups and an ether linkage. SOLUTION: This humidity-sensitive element has a humidity-sensitive film dispersed with conductive grains in a hygroscopic polymer between a pair of electrodes, and the hygroscopic polymer is polymerized with a polyester amine having two or more amino groups and an epoxy compound having two or more epoxy groups and an ether linkage. The hygroscopic polymer starts humidity absorption from the humidity range less than 90% RH, particularly 60-90% RH, it can detect the humidity not only in a high-humidity range of 90% RH or above but also in a low-humidity range below 90% RH. In particular, this humidity-sensitive element can detect humidity in the range of 60-100% RH.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-sensitive element having a moisture-sensitive film in which conductive particles are dispersed in a hygroscopic polymer.

[0002]

2. Description of the Related Art As a humidity sensing element for sensing humidity and dew condensation,
Known are those provided with a moisture-sensitive film in which conductive particles are dispersed in a hygroscopic polymer (JP-A-58-99740, JP-A-59-170755, JP-A-60-250241).
JP-A-62-21052, JP-A-6-24981
No. 3). At low humidity, the conductive particles are in contact with each other at low humidity to form a conductive path and exhibit low resistance, but at high humidity the hygroscopic polymer absorbs moisture and swells to cut the conductive path, resulting in a high resistance state. It is to become.

Another example of a moisture-sensitive element using a hygroscopic polymer is a humidity sensor which uses a polymer electrolyte having a quaternary ammonium base and utilizes the change in ionic conductivity (Japanese Patent Application Laid-Open No. HEI 7-1995). -318526). This humidity sensor has a function of 4 depending on the amount of moisture in the measurement atmosphere.
The degree of dissociation of the counter ion of the quaternary ammonium base changes,
Humidity is detected by utilizing a phenomenon in which an ion current flowing when a voltage is applied changes. However, a humidity sensor using a change in ionic conductivity needs to be measured by an alternating current, so that the circuit becomes complicated. Further, under high humidity of 90% RH or more, particularly in a dew atmosphere, the polymer electrolyte has poor water resistance such as partial elution, and the output differs even when the humidity is increased and decreased even when the humidity is decreased. The characteristic becomes unstable, for example, due to a hysteresis phenomenon showing a value.

On the other hand, a moisture-sensitive element in which conductive particles are dispersed in a hygroscopic polymer has the advantage that a direct current can be measured and the measurement circuit can be simplified. However, the detection of a moisture-sensitive element in which conductive particles are dispersed in a hygroscopic polymer can be detected only in a high humidity region in a range of 90% RH to dew condensation. Conventionally, hydroxy methacrylate or polyvinyl alcohol has been used as a hygroscopic polymer,
Since the water absorption rapidly increases at 90% RH or higher, a sufficient resistance value is not obtained for detecting a humidity lower than 90% RH, and the sensitivity is low.

Japanese Patent Publication No. 61-33374 discloses a moisture-sensitive resistor in which conductive particles are dispersed in an alcohol-soluble copolymerized polyamide resin. Although the resistance value of this one increases from about 60% RH, once it is exposed to a high humidity atmosphere, the resistance value does not completely return and becomes about twice the initial resistance value. Polyamide resin begins to absorb moisture at a relatively low humidity, but the amount of moisture absorption itself is small. To increase the resistance change of the moisture-sensitive element with respect to humidity change, it is necessary to reduce the filling amount of the conductive particles. Therefore, there are drawbacks that the resistance value during drying is high and the resistance value becomes unstable. Tokiko Sho 61-3337
No. 4 discloses a resistance value of 5 when dried.
The change of the resistance value is about 3.5 k digits, which is not enough characteristics.

[0006] As described above, there has not been obtained a moisture-sensitive element having a moisture-sensitive film in which conductive particles are dispersed in a hygroscopic polymer and capable of stably detecting a humidity of less than 90% RH. When the humidity sensing element is used in an air conditioner or a humidifier, it is used not only in a high humidity area of 90% RH or more, but also in a low humidity area, especially 60 to 90
There is a need for a moisture-sensitive element that can detect the humidity in the% RH region.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measurable direct current, less than 90% RH, especially 60-100% RH.
An object of the present invention is to provide a moisture-sensitive element that can detect the humidity in the region H and has high characteristic stability against repeated operations.

[0008]

The above object is achieved by the present invention described below. (1) A moisture-sensitive element having a moisture-sensitive film in which conductive particles are dispersed in a hygroscopic polymer between a pair of electrodes, wherein the hygroscopic polymer is a polyetheramine having two or more amino groups. 2. A moisture-sensitive element which is a polymer of an epoxy compound having two or more epoxy groups and further having an ether bond. (2) The moisture-sensitive element according to the above (1), wherein the polyether skeleton of the polyetheramine is propylene oxide and / or ethylene oxide. (3) The moisture-sensitive element according to the above (1) or (2), wherein the polyetheramine has two or three primary amino groups at a terminal. (4) The polyetheramine has a molecular weight of 100 to 5
The moisture-sensitive element according to any one of the above (1) to (3), which is 000. (5) The moisture-sensitive element according to any one of the above (1) to (4), wherein the epoxy compound is represented by the following formula (1).

[0009]

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[In the formula (1), A represents a divalent to tetravalent aliphatic saturated hydrocarbon group, an aliphatic ether group or a heterocyclic ring, and k is an integer of 2 to 4. (6) The moisture-sensitive element according to any one of (1) to (5), wherein the amine value and the epoxy value of the hygroscopic polymer are 1: 1 to 1: 4. (7) A moisture-sensitive element having a moisture-sensitive film in which conductive particles are dispersed in a moisture-absorbing polymer between a pair of electrodes, wherein the moisture-absorbing polymer is polyetheresteramide. (8) The moisture-sensitive element according to (7), wherein the polyetheresteramide is represented by the following formula (2).

[0011]

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[In the formula (2), R represents 2 to 12 carbon atoms.
M is an integer of 6 to 12, n is an integer of 1 to 4, p is an integer of 1 to 70, q is an integer of 5 to 200, and r is 3 or more. Is an integer. (9) The moisture-sensitive element according to the above (8), wherein m is 11 and n is 2 in the above formula (2). (10) The conductive particles have a specific surface area of 30 to 300 m ² / g.
Any of the above (1) to (9), which is a carbon black. (11) The moisture-sensitive element according to any one of (1) to (10) above, which is capable of detecting humidity in a range of 60 to 100% RH.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The moisture-sensitive element of the present invention has a moisture-sensitive film in which conductive particles are dispersed in a hygroscopic polymer between a pair of electrodes. Is a polymer of a polyetheramine having an amino group and an epoxy compound having two or more epoxy groups and further having an ether bond.

A polymer of a polyetheramine having two or more amino groups and an epoxy compound having two or more epoxy groups and further having an ether bond is 90%
Since moisture absorption starts from a humidity region lower than RH, particularly from 60% RH to 90% RH, it is possible to detect not only a high humidity region of 90% RH or more but also a low humidity region of less than 90% RH. In particular, the humidity-sensitive element of the present invention has a 60-100% R
The humidity in the region of H can be detected.

Further, since the amount of moisture absorption is as large as 10 to 20% by weight, a large amount of conductive particles can be taken, and stable resistance and humidity characteristics can be obtained. It is considered that the hygroscopicity of the hygroscopic polymer used in the present invention is mainly expressed by an ether bond (-O-), and an amino group and a hydroxyl group also contribute. The humidity-sensitive element of the present invention has a dry resistance of about 400 to 2 kΩ, and a change in resistance of about 4 to 6 digits.

Moreover, the humidity-sensitive element of the present invention has extremely stable resistance-humidity characteristics even when repeatedly exposed to a dry atmosphere and a high-humidity atmosphere, and its change is extremely small even after 400 cycles.

Further, since a moisture-sensitive film in which conductive particles are dispersed in a hygroscopic polymer is used, direct current measurement is possible.
The measurement circuit can be simplified and the cost is low.

First, the polyetheramine used for the hygroscopic polymer will be described. The polyetheramine refers to a polyoxyalkyleneamine and is a compound containing a primary amino group at a terminal of a polyether skeleton.

The polyether skeleton may be any of alkylene oxides, but is preferably propylene oxide (PO), ethylene oxide (EO) or mixed EO / PO. In the case of mixed EO / PO, EO / PO is arbitrary, but the larger the EO / PO, the lower the humidity can be detected. E
If it has an O skeleton, it is completely dissolved in water, and if it has only an EO skeleton, it is much more reactive than the others. When the EO skeleton is used, the resistance value increases due to low humidity.
Stability against repeated operations tends to decrease.

The number of terminal amino groups is 2 or more, preferably 2
It is preferable to have up to three. That is, diamines and triamines are preferred.

The molecular weight of the polyetheramine is 1
It is preferably from 00 to 5000, particularly preferably from 100 to 2000. If the molecular weight is too large, the resistance value tends to increase from higher humidity. When a mixture is used, the number average molecular weight (Mn) is preferably in the above range.

The polyetheramine of diamine is synthesized by reacting a dihydric alcohol with an alkylene oxide, preferably propylene oxide and / or ethylene oxide, and then converting the terminal hydroxy group to an amino group. Examples of the diol include ethylene glycol and propylene glycol.

The polyetheramine of triamine is synthesized by reacting an initiator, such as triol, with an alkylene oxide, preferably propylene oxide, and then converting the terminal hydroxy group to an amino group. Examples of the initiator triol include trimethylolpropane, glycerin and the like.

The total amine value of the polyetheramine used is preferably 0.3 to 15 meq / g, and particularly preferably 2 to 10 meq.
/ G is preferred. It is preferred that 95% or more thereof is a primary amine. If the amine value is larger than this, the crosslink density becomes excessively high, so that the water absorption decreases, and the sensitivity tends to decrease. If it is smaller than this, the degree of crosslinking tends to be low, and the water resistance tends to decrease.

The flash point of the polyetheramine used in the present invention is preferably 100 ° C. or higher, particularly preferably 120 to 300 ° C. If the flash point is lower than this, it becomes difficult to obtain sufficient safety.

Polyetheramine has a water content of 0.5 wt%
Or less, preferably 0.25 wt% or less.

Examples of such polyetheramines include polyoxymethyleneamine, polyoxyethyleneamine represented by the following formula (3), polyoxypropyleneamine represented by the following formulas (4) and (5), Examples include polyoxyethylene propylene amine represented by the following formula (6). Further, these derivatives may be used. One kind of polyetheramine may be used alone, or two or more kinds may be used in combination. When two or more kinds are used in combination, the quantitative ratio is arbitrary.

[0028]

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[0029]

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[0030]

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[0031]

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X in the formula (5) and a, b and c in the formula (6) are arbitrary integers.

The polyetheramine used in the present invention is commercially available. Examples of polyoxypropylenediamine include Jeffamine D-230, 40 manufactured by Texaco Chemical Company.
0, 2000, 4000 etc., as polyoxyethylene diamine, Texaco Chemical Jeffamine EDR-148 etc., and as polyoxyethylene propylene diamine Texaco Chemical Jeffamine ED-600, 900, 2003
Examples of polyoxypropylene triamines include Jeffamine T-403, 3000, and 5000 manufactured by Texaco Chemical Company.

Next, the epoxy compound used for the hygroscopic polymer will be described. The epoxy compound used in the present invention has two or more, preferably two to four epoxy groups, and further has an ether bond. By having an ether group, hydrophilicity is enhanced.

The epoxy group is preferably 1,2-epoxide, but may be 1,3-epoxide, 1,4-epoxide, 1,5-epoxide, or the like. Among them, a compound having 2 to 4 glycidyl groups is preferable, and an epoxy compound represented by the following formula (1) is particularly preferable.

[0036]

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In the formula (1), A represents a divalent to tetravalent saturated aliphatic hydrocarbon group, an aliphatic ether group or a heterocyclic ring. The carbon chain may have a branch, and may be substituted with a hydroxyl group or the like. Specifically, the following are mentioned.

[0038]

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K is an integer of 2 to 4.

Examples of such an epoxy compound having an ether structure include sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2 -Hydroxyethyl) isocyanurate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether,
Examples thereof include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. Further, these derivatives may be used. One epoxy compound may be used alone, or two or more epoxy compounds may be used in combination. When two or more kinds are used in combination, the quantitative ratio is arbitrary.

Epoxy compounds used in the present invention are commercially available. For example, sorbitol polyglycidyl ether is available from Nagase Kasei Denacol EX-611, 612, 614, 61.
4B etc., as sorbitan polyglycidyl ether, Nagase Kasei Denacol EX-651, 651A etc., as polyglycerol polyglycidyl ether, Nagase Kasei Denacol EX-512, 521 etc., as pentaerythritol polyglycidyl ether, Nagase Kasei. Denacol EX-4
11 etc., as the diglycerol polyglycidyl ether, Nagase Kasei Denacol EX-421 etc., as the triglycidyl tris (2-hydroxyethyl) isocyanurate, Nagase Kasei Denacol EX-301 etc., as the glycerol polyglycidyl ether, Nagase Kasei Denacol EX-313, 314, etc., as a trimethylolpropane polyglycidyl ether, Nagase Kasei Denacol EX-321
As for neopentyl glycol diglycidyl ether, Nagase Kasei Denacol EX-211 etc., as ethylene glycol diglycidyl ether, Nagase Kasei Denacol EX-810, 811 etc., and as polyethylene glycol diglycidyl ether, Nagase Kasei Denacol EX
-850, 851, 821, 830, 832, 841, 861 etc., as propylene glycol diglycidyl ether, Nagase Kasei Denacol EX-911 etc., and as polypropylene glycol diglycidyl ether, Nagase Kasei Denacol EX-9.
There are 41, 920, 921, 931 and so on.

The epoxy compound used in the present invention preferably has an epoxy equivalent of 50 to 700 WPE, particularly preferably 100 to 250 WPE. If the epoxy equivalent is larger than this, the crosslink density becomes excessively high, so that the water absorption decreases, and the sensitivity tends to decrease. If it is smaller than this, the degree of crosslinking tends to decrease, and the water resistance tends to decrease.

The water solubility of the epoxy compound used in the present invention is preferably from 15 to 100%, particularly preferably from 20 to 100%. If the water solubility is lower than this, the detectable humidity becomes high and may become 90% RH or more. Here, the water solubility refers to the dissolution rate when 10 parts by weight of the resin is dissolved in 90 parts by weight of water at 25 ° C.

The flash point of the epoxy compound used in the present invention is preferably 90 ° C. or higher, particularly preferably 120 to 300 ° C. If the flash point is lower than this, it becomes difficult to obtain sufficient safety.

The epoxy compound is preferably chlorine or the like.
It may contain 5 wt% or less, more preferably 15 wt% or less.

The hygroscopic polymer of the present invention uses the above-mentioned polymer of polyetheramine and epoxy compound. The polymerization is performed according to the following formula (7) using alcohol or water as a catalyst.

[0047]

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In the polymerization, a total of 10 to 80% by weight of a polyetheramine and an epoxy compound is added to alcohol or water,
Preferably added and dispersed so as to be 30 to 60 wt%,
Heating may be performed at 80 to 180 ° C, preferably 120 to 160 ° C, for 30 minutes to 3 hours, preferably 60 minutes to 2 hours.
As the dispersion medium, ethyl cellosolve, ethylene glycol and the like are preferable. The polymerization conditions are appropriately selected depending on the polyetheramine and the epoxy compound used, and are not limited to the above conditions. In addition, as will be described later, usually, conductive particles are also added to the dispersion medium, coated, and then heated to polymerize.

The composition of the polyetheramine and the epoxy compound having an ether structure preferably has an amine value and an epoxy value of from 1: 1 to 1: 4, particularly the same, from the viewpoint of characteristic stability. It is also possible to control the resistance / humidity characteristic by shifting the composition from the equivalent amount. In a composition in which the amount of the amine is excessive, the resistance value increases at lower humidity, but the characteristic stability tends to decrease.

The water absorption of the polymer of polyetheramine and epoxy compound at 25 ° C. and 80% RH is 4 to 2
It is preferably 0%, particularly preferably 6 to 15%. If the water absorption is higher than this, the change in resistance increases, but when exposed to a high-humidity region, the resistance may not return to the original value while increasing. If the water absorption is lower than this, the polymer will not swell sufficiently at the time of moisture absorption, and the sensitivity will decrease.

Further, in order to enhance the effects of the present invention, a hydrophobic or water-repellent substance may be added. For example,
A silicone oil, particularly a silicone oil modified with a functional group such as an amine or an epoxy group, or a long-chain alkyl having a functional group may be added. As described above, when the water absorption of the polymer of polyetheramine and epoxy compound is high, exposure to a high-humidity region may not be able to return to the original state with the resistance value increasing. Is done. The amount of the hydrophobic or water-repellent substance to be added is preferably 30% by weight or less, particularly preferably 3 to 20% by weight, based on the polymer of the polyetheramine and the epoxy compound. If the addition amount is more than this, the water absorption of the moisture-sensitive film decreases, and the sensitivity decreases. The silicone oil has a functional group equivalent of 100 to 2000 g / mol, particularly 200 to 1 g / mol.
000 g / mol is preferred.

In another embodiment of the present invention, a polyetheresteramide, preferably a polyetheresteramide represented by the following formula (2) may be used as the hygroscopic polymer. Also in this case, the same effect as a polymer of a polyetheramine having two or more amino groups and an epoxy compound having two or more epoxy groups and further having an ether bond can be obtained. It is possible to detect the humidity not only in the high humidity region described above but also in the low humidity region of less than 90% RH. This moisture sensitive element also has a
The humidity in the region of H can be detected. Further, since the moisture absorption is as large as 10 to 20% by weight, the filling amount of the conductive particles can be increased, and stable resistance / humidity characteristics can be obtained. Moreover, the resistance / humidity characteristics are extremely stable even when repeatedly exposed to a dry atmosphere and a high humidity atmosphere.

[0053]

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Such polyetheresteramides have a linear, regular chain structure of hard polyamide segments and flexible polyether segments. This material has excellent properties such as mechanical properties due to its dual properties. Polyetheresteramide is obtained by reacting a polyamide diacid oligomer with a polyetherdiol oligomer.

The polyetheresteramide used in the present invention is disclosed in French Patent Nos. 2,273,021, 2,401,947 and 2,384,810.
No. 7,007,559, U.S. Pat. Nos. 4,345,064, 4,349,661, 4,345,052, and French Patent Application 910.
No. 3,175, JP-A-7-102062 and the like are preferable. Also, European Patent 0,378,
No. 015, No. 0,476,963, JP-A-10-1
No. 58509.

As the polyetheresteramide used in the present invention, those represented by the above formula (2) are preferable.
In the formula (2), R has 2 to 12 carbon atoms, preferably 6 carbon atoms.
Represents an alkyl group of 1 to 12. The alkyl group represented by R may be linear or branched.
The alkyl group may further have a substituent, but is preferably an unsubstituted one. Specifically, a methyl group, an ethyl group, an (n-, i-) propyl group, a (n-, i-, s-,
t-) butyl group and the like.

In the formula (2), m is an integer of 6 to 12, preferably 6 to 11. n is 1 to 4, preferably 2
-3. p is 1 to 70, preferably 5 to 30
Is an integer. q is 5 to 200, preferably 10 to 10
It is an integer of 0. r is 3 or more, preferably 3 to 1000
Is an integer.

In particular, in the above formula (2), it is preferable that m is 11 and n is 2.

The degree of polymerization of the polyamide segment p
And the degree of polymerization q of the polyether segment, q is preferably larger or equivalent. If the polyamide segment is longer, the water absorption tends to decrease and the sensitivity tends to decrease.

The water absorption at 20 ° C. and 65% RH is preferably from 0.3 to 10%, particularly preferably from 3 to 8%.
If the water absorption is higher than this, the change in resistance increases, but when exposed to a high-humidity region, the resistance may not return to the original value while increasing. If the water absorption is lower than this, the polymer will not swell sufficiently at the time of moisture absorption, and the sensitivity will decrease.

The melting point of the polyetheresteramide represented by the formula (2) is about 120 to 210 ° C., preferably 1 to 210 ° C.
60-210 ° C. The glass transition temperatures are all about -60 ° C. The melting point depends on the polyamide phase.
The glass transition temperature is due to the polyether phase.

Such polyetheresteramides are commercially available as PEBAX33 series, 12 series, 62 series, 11 series, etc., manufactured by Atochem.

Further, also in this case, a hydrophobic or water-repellent substance may be added. For example, a silicone oil, particularly a silicone oil modified with a functional group such as an amine or an epoxy group, or a long-chain alkyl having a functional group may be added. As described above, when the water absorption of the polyetheresteramide is high, exposure to a high-humidity region may cause the resistance value to rise and not return to its original state. The amount of the hydrophobic or water-repellent substance to be added is preferably 30% by weight or less, particularly preferably 3 to 20% by weight, based on the polyetheresteramide. If the addition amount is more than this, the water absorption of the moisture-sensitive film decreases, and the sensitivity decreases. The silicone oil has a functional group equivalent of 100 to 2000 g / mol, particularly 200 to 1 g / mol.
000 g / mol is preferred.

The conductive particles used in the present invention include carbon-based particles such as carbon black and graphite, and metal powders such as nickel, gold, silver, and copper. Particularly, carbon black and the like are preferably used. Carbon black has a specific surface area of 30 to 300 m ² / g,
It is preferably from 150 to 150 m ² / g, particularly preferably from 30 to 75 m ² / g. The average particle size of the primary particles of carbon black is preferably 20 to 50 nm, and those having a well-developed structure are preferable, and the DBP oil absorption is 100 ml / 100 g or more (typically
0 ml / 100 g or less) is preferable. In general, it is preferable that the average particle size of the conductive particles (when the particles are not spherical particles, the diameter when the projected area is converted into a circle) is about 20 nm to 3 μm.

The filling amount of the conductive particles in the moisture-sensitive film of the present invention is 5 to 40% by weight in the case of carbon black.
And more preferably 10 to 30% by weight. When the filling amount of the conductive particles is small, the resistance value during drying becomes too high, and the resistance value changes when repeatedly exposed to a dry atmosphere and a high humidity atmosphere. If the amount is too large, the change in the resistance value with respect to the change in the humidity becomes small,
The sensitivity as a moisture-sensitive element decreases. The other conductive particles may have a filling amount according to this.

In the present invention, the method for forming the moisture-sensitive film is not limited, but may be formed by coating using a dispersion containing the constituent material of the moisture-sensitive film. As the dispersion medium, water, alcohols, ethers, and ketones are preferable, and a medium for mixing these may also be used. As a coating method, a screen printing method is usually used.

After forming the coating film, it is cured at a temperature of about 80 to 180 ° C. for about 30 minutes to 3 hours. Curing conditions are appropriately selected depending on the polyetheramine and the epoxy compound used, and are not limited to the above conditions. At this time, the polyetheramine and the epoxy compound are polymerized.

The dry thickness of the moisture-sensitive film thus obtained is preferably 5 μm or less, particularly preferably 1 to 3.5 μm. Thereby, permeation of moisture is sufficiently ensured.

The moisture-sensitive element of the present invention is not limited as long as it has a moisture-sensitive film between a pair of electrodes, and may have, for example, the structure shown in FIG.

As shown in FIG. 1, the moisture-sensitive element 1 has a pair of comb electrodes 4 on an insulating substrate 2, and a pair of comb electrodes 4.
Are arranged on the insulating substrate 2 via a gap 5 at a fixed distance and in mesh with each other. Then, a moisture-sensitive film 3 is provided on the insulating substrate 2 and the comb-shaped electrode 4 as shown in the figure. An electrode terminal 6 is attached to one end of each of the comb-shaped electrodes 4. Further, as shown, a resist film 9 may be provided.

With such a configuration, a voltage is applied between both electrodes. The output voltage changes due to a change in resistance according to the humidity of the moisture-sensitive film, and the humidity is detected.

Referring to FIG. 1, as the insulating substrate 2 used in the present invention, any material may be used as long as it has good adhesion to the moisture sensitive film 3 and has electrical insulation. For example, glass, plastic, ceramic or metal coated with insulation is used.

The electrode 4 is not particularly limited as long as it is a commonly used electrode. For example, the electrode 4 contains Au, RuO ₂ , carbon particles such as carbon black and graphite, and further contains glass frit as required. A low-resistance paste or the like which is screen-printed and sintered at a high temperature can be used. The electrode terminals 6 may be made of, for example, an Ag-Pd alloy, and may be printed by a normal method and baked at a high temperature. Further, as shown in FIG. 1, a resist film 9 made of glass or the like may be provided. The thickness and shape of the resist film 9 are not limited.

The humidity sensor element of the present invention is not limited to the illustrated example, but may be various types.

The gap between the pair of electrodes in the present invention is usually about 0.1 to 1.0 mm.

[0076]

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> To 3 g of ethyl cellosolve, polyoxypropylenediamine Jeffamine D400 (number average molecular weight 400, amine value 4.4 meq /
g, viscosity (20 ° C) 29cp) 0.342g, Jeffamine D2000 (number average molecular weight 2000, amine value 1.
0meq / g, viscosity (20 ° C) 342 cp) 0.228 g, carbon black (Tokai Carbon Toka Black # 45)
00F) 0.36 g was added, and this was dispersed with a Kurabo Industries planetary stirrer KK-100 for 9 minutes. And sorbitol polyglycidyl ether EX614 manufactured by Nagase Kasei
B (epoxy equivalent 180 WPE, water solubility 90%, viscosity (2
5 ° C) 4000 cps, specific gravity (25 ° C) 1.26) 1.0
87 g was added and the mixture was further dispersed for 1 minute to obtain a moisture-sensitive paste.

A moisture-sensitive material paste was printed by screen printing on a pair of comb-shaped electrodes made of ruthenium oxide on an alumina substrate, and then cured at 150 ° C. for 1 hour to obtain a moisture-sensitive element (see FIG. 1). . The dry thickness of the moisture-sensitive film was 3 μm.

Example 2 0.342 g of polyoxypropylenediamine Jeffamine D400 (number average molecular weight 400, amine value 4.4 meq / g, viscosity (20 ° C.) 29 cp) manufactured by Texaco Chemical Co., Ltd. was added to 3 g of ethyl cellosolve.
Jeffamine D2000 (number average molecular weight 2000, amine value 1.0 meq / g, viscosity (20 ° C.) 342 cp) 0.2
28 g, carbon black (Tokai Carbon # 4500F, 0.36 g), silicone oil modified with amino group (KF393, Shin-Etsu Chemical, molecular weight 700)
-1000), and dispersed with a Kurabo Industries planetary stirrer KK-100 for 9 minutes. And Nagase Kasei sorbitol polyglycidyl ether EX61
4B (epoxy equivalent 180WPE, water solubility 90%, viscosity (25 ° C) 4000 cps, specific gravity (25 ° C) 1.26)
1.087 g was added, and the mixture was further dispersed for 1 minute to obtain a moisture-sensitive paste.

A moisture sensitive material paste was printed by screen printing on a pair of comb-shaped electrodes made of ruthenium oxide on an alumina substrate, and then cured at 150 ° C. for 1 hour to obtain a moisture sensitive element. The dry thickness of the moisture-sensitive film was 3 μm.

Example 3 Polyoxypropylenediamine Jeffamine D400 manufactured by Texaco Chemical Co. (number average molecular weight 400, amine value 4.4 meq / g, viscosity (20
C) 29 cp) 0.623 g, sorbitol polyglycidyl ether EX614B manufactured by Nagase Kasei (epoxy equivalent 180 WPE, water solubility 90%, viscosity (25 ° C.) 4000 cp)
s, 1.377g of specific gravity (25 ° C) 1.26g,
A moisture-sensitive element was obtained in the same manner as in Example 2.

<Example 4> Polyoxypropylene diamine Jeffamine D230 (Texaco Chemical Co., Ltd.) (number average molecular weight 230, amine value 8.45 meq / g, viscosity (2
0 ° C) 14cp) 0.423g, sorbitol polyglycidyl ether EX614B manufactured by Nagase Kasei (epoxy equivalent 180WPE, water solubility 90%, viscosity (25 ° C) 4000c)
Using 1.76 g of ps, specific gravity (25 ° C. 1.26),
A moisture-sensitive element was obtained in the same manner as in Example 2.

<Example 5> Polyoxypropylene triamine Jeffamine T403 manufactured by Texaco Chemical Company
(Number average molecular weight 440, amine value 6.4 meq / g, viscosity (20 ° C.) 95 cp) 0.532 g, Nagase Kasei sorbitol polyglycidyl ether EX614B (epoxy equivalent 180 WPE, water solubility 90%, viscosity (25 ° C.) 40
A moisture-sensitive element was obtained in the same manner as in Example 2, except that 1.468 g of 00 cps and specific gravity (25 ° C. 1.26) were used.

Example 6 Polyoxyethylene propylene diamine Jeffamine ED manufactured by Texaco Chemical Company
600 (number average molecular weight 600, EO / PO = 3.4, amine value 3.19 meq / g, viscosity (20 ° C.) 75 cp) 0.8
32 g, sorbitol polyglycidyl ether EX614B manufactured by Nagase Kasei (epoxy equivalent 180 WPE, water solubility 90%, viscosity (25 ° C) 4000 cps, specific gravity (25 ° C)
1.26) Using 1.168 g, a moisture-sensitive element was obtained in the same manner as in Example 2.

<Comparative Example 1> 10 g of propylene glycol
To alcohol-soluble copolymerized nylon (CM40 manufactured by Toray)
00) 1 g was dissolved, and 0.2 g of carbon black (Tokai Carbon # 4500F, manufactured by Tokai Carbon Co., Ltd.) was added. This was dispersed with a Kurabo Industries planetary stirrer KK-100 to obtain a moisture-sensitive paste.

A moisture-sensitive material paste was printed by screen printing on a pair of comb-shaped electrodes made of ruthenium oxide on an alumina substrate, and then heated at 150 ° C. for 1 hour to obtain a moisture-sensitive element. The dry thickness of the moisture-sensitive film was 3 μm.

Comparative Example 2 Propylene glycol 10 g
To alcohol-soluble copolymerized nylon (CM40 manufactured by Toray)
00) 1 g was dissolved, and 0.3 g of carbon black (Tokai Black # 4500F, manufactured by Tokai Carbon Co., Ltd.) was added, and the resultant was dispersed with a Kurabo Industries planetary stirrer KK-100 to obtain a moisture-sensitive material paste.

A moisture-sensitive material paste was printed by screen printing on a pair of comb-shaped electrodes made of ruthenium oxide on an alumina substrate, and then heated at 150 ° C. for 1 hour to obtain a moisture-sensitive element. The dry thickness of the moisture-sensitive film was 3 μm.

FIGS. 2 and 3 show the resistance-humidity characteristics of the humidity-sensitive elements of Examples 1 to 6, and FIG. 4 shows the resistance-humidity characteristics of the humidity-sensitive elements of Comparative Examples 1 and 2. In Comparative Example 1, once exposed to the humidity of 100% RH, the resistance value does not return even when the atmosphere is returned to the low humidity atmosphere. In Comparative Example 2 in which the amount of carbon black was increased, the amount of increase in the resistance value was small. On the other hand, in Examples 1 to 6, a sufficient increase in the resistance value is obtained, and the resistance value returns to the original value by returning to the low humidity atmosphere after being exposed to the humidity of 100% RH.

FIG. 5 shows the moisture-sensitive element of Example 2 with 0%
The resistance-humidity characteristics of the characteristics when repeatedly exposed 400 times to the RH atmosphere and the 100% RH atmosphere are shown. Almost no change in resistance / humidity characteristics is observed. Other Examples 1 and 3
Similar results were obtained with the moisture-sensitive elements of Nos. 1 to 6.

Also, 0.34 g of polyoxyethylenediamine Jeffamine EDR148 (number average molecular weight: 148, amine value: 13.5 meq / g) manufactured by Texaco Chemical Co., Ltd.
Nagase Kasei sorbitol polyglycidyl ether Denacol EX-614B (epoxy equivalent 180 WPE, water solubility 90
%, Viscosity (25 ° C.) 4000 cps, specific gravity (25 ° C.)
26) Even when a moisture-sensitive element was obtained in the same manner as in Example 2 using 1.66 g, the same results as in Example 2 were obtained.

A polyglycerol polyglycidyl ether Denacol EX-512 (epoxy equivalent 173 WPE, water solubility 100%, viscosity (25 ° C.) 1500 c, manufactured by Nagase Kasei Co., Ltd.)
ps, specific gravity (25 ° C.) 1.24) 1.025 g, polyoxypropylenediamine Jeffamine D400 manufactured by Texaco Chemical Co. (number average molecular weight 400, amine value 4.4)
meq / g, viscosity (20 ° C) 29cp) 0.351g, Jeffamine D2000 (number average molecular weight 2000, amine value 1.0meq / g, viscosity (20 ° C) 342cp) 0.234g
When a moisture-sensitive element was obtained in the same manner as in Example 2 using the same method, the same results as in Example 2 were obtained.

Further, pentaerythritol polyglycidyl ether Denacol EX-411 (epoxy equivalent 231 WPE, water solubility 27%, viscosity (25 ° C.) 760 c, manufactured by Nagase Kasei Co., Ltd.)
ps, specific gravity (25 ° C. 1.24) 1.168 g, polyoxypropylenediamine Jeffamine D400 manufactured by Texaco Chemical Co. (number average molecular weight 400, amine value 4.4)
meq / g, viscosity (29 ° C) 29cp) 0.299g, Jeffamine D2000 (number average molecular weight 2000, amine value 1.0meq / g, viscosity (20 ° C) 342cp) 0.199g
When a moisture-sensitive element was obtained in the same manner as in Example 2 using the same method, the same results as in Example 2 were obtained.

<Example 7> A polyetheresteramide PEBAX40 manufactured by Atochem was added to 5 g of ethyl cellosolve.
11 (specific gravity 1.14, water absorption (20 ° C, 65% RH)
2 g of 4.5%) and 0.32 g of carbon black (Toka Black # 4500F, manufactured by Tokai Carbon Co., Ltd.) were added thereto, and dispersed with a Kurabo Industries planetary stirrer KK-100 for 10 minutes to obtain a moisture-sensitive paste.

A humidity sensitive material paste was printed by screen printing on a pair of comb-shaped electrodes formed of ruthenium oxide on an alumina substrate, and then cured at 150 ° C. for 1 hour to obtain a moisture sensitive element (see FIG. 1). . The dry thickness of the moisture-sensitive film was 3 μm. The same result as that of Example 1 was obtained in this moisture sensitive element.

[0095]

According to the present invention, DC measurement is possible and
Humidity in a region of less than 0% RH, particularly in the range of 60 to 100% RH can be detected, and a moisture-sensitive element having high characteristic stability against repeated operation can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing one configuration example of a moisture-sensitive element of the present invention.

FIG. 2 is a graph showing resistance-humidity characteristics of the moisture-sensitive elements of Examples 1 and 2.

FIG. 3 is a graph showing resistance-humidity characteristics of the moisture-sensitive elements of Examples 3 to 6.

FIG. 4 is a graph showing resistance-humidity characteristics of the moisture-sensitive elements of Comparative Examples 1 and 2.

FIG. 5 is a graph showing resistance-humidity characteristics of the humidity-sensitive element of Example 2 at an initial stage and after 400 cycles.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moisture sensitive element 2 Insulating substrate 3 Moisture sensitive film 4 Electrode 5 Gap 6 Electrode terminal 9 Resist film

Claims (11)

[Claims] 1. A moisture-sensitive device having a moisture-sensitive film in which conductive particles are dispersed in a moisture-absorbing polymer between a pair of electrodes, wherein the moisture-absorbing polymer has a polyether having two or more amino groups. A moisture-sensitive element which is a polymer of an amine and an epoxy compound having two or more epoxy groups and further having an ether bond. 2. The moisture-sensitive element according to claim 1, wherein the polyether skeleton of the polyetheramine is propylene oxide and / or ethylene oxide. 3. The moisture-sensitive element according to claim 1, wherein the polyetheramine has two or three primary amino groups at a terminal. 4. The polyetheramine having a molecular weight of 10
The moisture-sensitive element according to claim 1, wherein the number is from 0 to 5,000. 5. The moisture-sensitive element according to claim 1, wherein the epoxy compound is represented by the following formula (1). Embedded image [In the formula (1), A represents a divalent to tetravalent saturated aliphatic hydrocarbon group, an aliphatic ether group or a heterocyclic ring, and k is an integer of 2 to 4. ] 6. The moisture-sensitive element according to claim 1, wherein the hygroscopic polymer has an amine value and an epoxy value of 1: 1 to 1: 4. 7. A moisture-sensitive element having a moisture-sensitive film in which conductive particles are dispersed in a moisture-absorbing polymer between a pair of electrodes, wherein the moisture-absorbing polymer is polyetheresteramide. 8. The moisture-sensitive element according to claim 7, wherein the polyetheresteramide is represented by the following formula (2). Embedded image [In the formula (2), R represents an alkyl group having 2 to 12 carbon atoms, m is an integer of 6 to 12, n is an integer of 1 to 4, p is an integer of 1 to 70, q is an integer of 5 to 200, and r is an integer of 3 or more. ] 9. The moisture-sensitive element according to claim 8, wherein in the formula (2), m is 11 and n is 2. 10. The conductive particles have a specific surface area of 30 to 30.
Any moisture sensitive element according to claim 1 to 9 carbon black 0 m ² / g. 11. The moisture-sensitive element according to claim 1, wherein a humidity in a range of 60 to 100% RH can be detected.