JPS58193445A - Moisture sensor and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve environmental resistance and to stabilize a moisture sensitive characteristic for a long period by a method wherein a moisture sensitive material is formed of an aggregate of fine particles each comprising a hydrophobic nucleus and a cationic surface layer coating the nucleus, and a protective coating made of silicone resin is formed thereon. CONSTITUTION:Gold electrodes 5, a moisture sensitive material 3, lead wire connection terminals 7 and a protective film 6 are formed on an alumina substrate 4 in a fashion as illustrated. The moisture sensitive material, i.e., latex, is coated on the alumina substrate provided with the comb-type metal electrodes 5 and then dried to attain an electric resistance type moisture sensor. Methacrylic acid of 0.2mol and methylenebisacrylamide of 0.01 mole as a hydrophobic monomer, 2-methaacryloyloxyethyltrimethylammoniumiodide of 0.1 mole as a cationic monomer and azobisisobutylamidinhydrochloride of 0.001 mole as a polymerization starting agent are emulsified and copolymerized in a water medium of 300l under the atmosphere of nitrogen for 10hr at 60 deg.C while agitating at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a humidity sensor and a method of manufacturing the same, and more particularly to an electrical resistance type humidity sensor whose electrical resistance changes in accordance with the humidity around the chest to 1%, and a method of manufacturing the same.

#j standard method for relative humidity includes mechanical measurement method and electrical measurement method. The electrical measuring method is advantageous over the mechanical measuring method in that the structure of the measuring device can be made smaller, the sensing speed of the measuring device is faster, and it is easier to convert m degrees into an electrical signal. For electrical measurement methods.

Utilizes the moisture-sensitive properties of moisture-sensitive materials. Use an electrical resistance type moisture sensing element. This moisture sensing element has an insulating substrate.

It consists of a pair of electrodes arranged on this insulating substrate, and a moisture sensitive material layer covering the key and the electric wire.

Conventional moisture sensitive materials used in such electrical resistance type moisture sensitive elements are as follows.

(1) Selantux materials (2) Electrolyte salts such as lithium chloride (L i CJ ) (
3) Hygroscopic resin with conductive powder dispersed therein (4) Hydrophilic polymer compound or polymer electrolyte These moisture-sensitive materials each have the following drawbacks.

Concerning (1): The adhesion of moisture to ceramics is partially due to chemical adsorption, and therefore a moisture sensing element using this moisture sensing material has a large hysteresis.

Poor responsiveness. Moreover, if left in a high humidity atmosphere for a long time, the shape is likely to change.

Regarding (2): In a high humidity atmosphere, it deliquesces, dilutes, and flows out. Therefore, using this moisture-sensitive material, the lifespan of the nine-sensing moisture-sensitive material is extremely short. Furthermore, the humidity range that can be produced by -1 ml of humidity sensing elements is narrow.

Regarding (3): It does not exhibit moisture sensitivity in a low humidity atmosphere. Furthermore, it is difficult to make the degree of dispersion of the four-part powder uniform.For this reason, the manufacturing yield of the moisture-sensitive element is extremely low and the reliability is also poor.

Regarding (4), the above three types also have good moisture sensitivity characteristics, but the amount of moisture absorption is large, so depending on the amount of moisture in the atmosphere,
, shrinkage occurs, and the adsorbent layer is likely to peel off from the substrate or electrode.

Generally speaking, conventional electrical resistance type humidity sensors have the drawback of poor final stability and reliability of humidity sensing characteristics. Particular attention had to be paid to moisture condensation. The reason for this is that when water condenses (condenses) on the surface of the moisture-sensitive material, the moisture-sensitive material is locally dissolved and the moisture-sensitive characteristics change. Another type of organic gas that is generated in places where people live.

For example, if an armpit sensor was exposed to vapors from cigarettes or cooking oil, its moisture-sensing characteristics would change, making it unsuitable for practical use. In addition, temperature, low temperature, high humidity, low humidity, l, such as summer, winter, rainy season, and dry season.

However, it also had the disadvantage that it was not resistant to environmental changes over a period of nine cycles, and its moisture sensitivity characteristics changed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable humidity sensor which eliminates the above-mentioned drawbacks, has excellent environmental resistance, and whose humidity sensitive characteristics can operate stably for a long period of time.

The humidity sensor of the present invention is characterized by a moisture sensitive material and a coating material that protects the moisture sensitive material layer. A moisture-sensitive material is an aggregate of fine particles consisting of a hydrophobic core and a cationic surface layer surrounding the core.
The adhesive film is silicone resin. The method for producing this humidity sensor is characterized by the method of synthesizing the fine particles as latex particles in aqueous solution and the method of forming the film. The film is formed by applying a silicone resin face to the surface of the latex particle aggregate film and then drying or reacting the film.

An example of the humidity sensor of the present invention is shown in FIG. 1, which is a schematic cross-sectional view of the humidity sensor. A moisture film 3 covers a pair of electrodes 5 disposed on an insulating substrate 4, and a silicone resin protective film 6 covers the moisture sensitive film. The shape of the nucleus 1 is not limited to %, therefore, it is not limited to spherical shape, but may be rod-shaped or plate-shaped. However, since it is used as the film 3 of the insulating substrate 4, it is preferable that the particles densely fill the electrode 5. Therefore, the average particle diameter is actually about 100 μm.
The following are preferred.

The substance forming the core and the substance forming the surface layer may be one in which the core is hydrophobic and the surface layer is hydrophilic with a cationic group. Therefore, it does not need to be a polymer compound, but it is acceptable if the nucleus and the surface layer are made of the same compound.In the case of a polymer compound, even if it is a linear polymer compound, the It may be a polymer compound.

One form of particles, such as latex particles synthesized in an aqueous solution, is one in which hydrophobic compounds or groups constituting each particle gather in the center to form a core, and cationic compounds or groups are exposed on the outside. The surface layer can be mentioned as follows. It was. For moss of 3 or more woodcutters, the boundary between the &men layer and the core is not necessarily clear.

It is certain that the rubet and surface layers on the core exhibit ionic or hydrophilic properties. In most cases, ions are uniformly distributed in the surface layer. The particles may contain some amount of ionic or hydrophilic groups in the core.

The surface of latex particles synthesized in an aqueous solution naturally becomes hydrophilic, which has the advantage that the moisture-sensitive material used in the present invention can be easily obtained.

By forming a protective film of silicone resin on the surface of the pressure-moisture-sensitive material film described above, first, the first K moisture-sensitive material film will no longer come into direct contact with water droplets, dust, corrosive gases, or chemicals in the atmosphere due to dew condensation. Therefore, it is possible to prevent the deterioration of the moisture-sensitive material and a decrease in its moisture-sensitive properties.Secondly, by preventing abnormal swelling under high temperatures11, it improves the stability and reliability of the humidity sensor. can be improved.

The moisture-sensitive skin aFi used in the humidity sensor of this example is usually obtained by coating a latex obtained by copolymerizing a cationic vinyl monomer and a nonionic vinyl monomer in water or an aqueous medium to cover the electrodes and drying. It will be done. Depending on the necessity, cationic or nonionic divinyl monomer, trivinyl monomer or tetravinyl monomer may be used as a crosslinking agent, and as a catalyst for copolymerization reaction of two or more types of vinyl type monomers. teeth.

Generally, benzoyl peroxide is not particularly limited as long as it is 4 used for vinyl Togane.

A peroxide polymerization initiator such as potassium persulfate and an azo compound polymerization initiator such as azobisisobutylnitrile and azobisisobutylandine hydrochloride can be used, but the invention is not limited thereto.

The cationic monomers used in the present invention include 2-methacryloyloxyethyltrimethylammonium, 2-methacryloyloxyethyltrimethylammonium,
-methacryloyloxyethyldimethylethylammonium, 2-methacryloyloxyethyldimethylbutylammonium, 2-methacryloyloxyethyldimethyloctylammonium, 2-methacryloyloxyethyltriethylammonium, 2-methacryloyloxyethyldiethylbutylammonium, 2-methacryloyloxyethyldiethyloctyl ammonium, 2-
Acryloyloxyethyltrimethylammonium, 2
-acryloyloxyethyldimethyloctylammonium, 2-acryloyloxyethyltriethylammonium, 2-acryloyloxyethyldiethyloctylammonium, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium, 2-hydroxy-3-methacryloyloxypropyltriethylammonium, 2-Hydroxy-3-aryloyloxypropyltriethylammonium, 2-hydroxy-3-
Allyloxypropyltriethylammonium, 2
-Hydroxy-3-aryloyloxypropyltrimethylammonium.

Quaternary ammonium hydroxides or salts thereof such as 2-hydroxy-3-aryloyloxypropyltriethylammonium, vinylbenzyltrimethylammonium, vinylbenzyltriethylammonium, N-methyl-
4-vinylpyridinium, N-ethyl-4-vinylpyridinium, N-butyl-4-vinylpyridinium%
N-octyl-4-vinylpyridinium, N-methyl-
Hydroxides and salts of viridiniums such as 2-vinylpyridinium and N-ethyl-2-vinylpyridinium;
There are hydroxides of phosphoniums such as vinyltriphenylphosphonium or their salts.

Anions that form salts with these cations include chloride ions, bromide ions, fluoride ions, hydrogen ions, acetate ions, nitrate ions, and sulfate ions.

There are phosphate ions, etc. The cationic groups of these cationic monomers and the ammonium group in the divinyl warm monomer are pyridinium groups in the moisture-sensitive organic polymer, so that their cations respond to changes in humidity in the outside world. The counter-anion of the group dissociates, and the counter-anion becomes a charge carrier, thereby changing the electrical resistance of the moisture-sensitive material.

There are various nonionic monomers constituting the moisture-sensitive organic polymer suitable for the present invention. For example, methacrylic esters such as methyl methacrylate and droxyethyl methacrylate, acrylic esters such as ethyl acrylate and methyl acrylate, vinyl monomers such as styrene, vinyl acetate, vinyl chloride and acrylonitrile, ethylene, propylene, Although there are hydrocarbon monomers such as butadiene and isoprene, the monomers are not limited to these, and any monomer that does not have an ionic group in the molecule may be used. When these nonionic monomers constitute the organic polymer moisture-sensitive material of the present invention, they impart hydrophobicity to the moisture-sensitive material and contribute to improved moisture resistance. Furthermore, the electrical resistance value of the moisture-sensitive material can be controlled by changing the composition ratio of the nonionic monomer in the moisture-sensitive organic polymer chain.

When using the moisture sensitive skin MK crosslinking agent used in the present invention, the type is not limited to % as long as it is a monomer having 2 to 4 vinyl groups.

Typical examples include divinylbenzene, diallyl phthalate, ethylene glycol dimethacrylate, ethylene glycol cyacrylate, methylene bisacrylamide, and triallyl isocyanurate.

In addition, it is possible to use a divinyl type monomer containing 4M am7nium in one molecule as a crosslinking agent. This divinyl type monomer is produced by the reaction of a vinyl monomer having a glycidyl group such as glycidyl methacrylate with a vinyl monomer having a tertiary azuno group such as dimethylaminoethyl methacrylate in the presence of oxygen. 6864
7) or vinylbenzyl chloride
It is obtained by the reaction of a vinyl monomer having an alkyl group with a monomer having a tertiary amino group such as dimethylaminoethyl acrylate. It is also possible to use a divinyl-type monomer having an intramolecular pressure pyridinium group as a cross-linking agent, but this type of divinyl-type monomer is a combination of a vinyl monomer having a pyridine ring such as 4-vinylpyridine and a monomer such as metallyl chloride. It is synthesized by reaction with a vinyl monomer having a group. Specific examples of divinyl type monomers having this quaternary ammonium group include (2
-hydroxy-3-methacryloyloxypropyl) (
2-methacryloyloxyethyl)dimethylammonium hydroxide or its salt, (2-hydroxy-3-methacryloyloxypropyl)(2-methacryloyloxyethyl)diethylammonium hydroxide or its salt, (2-hydroxy -3-acryloyloxypropyl)(2-methacryloyloxyethyl)dimethylammonium hydroxide or its salt, (2-hydroxy-3-methacryloyloxypropyl)(2-acryloyloxyethyl)dimethylammonium hydroxide or its salt Salt, (2-hydroxy-3-aryloyloxypropyl) (2-methacryloyloxyethyl) dimethylammonium hydroxide or its salt, (2-hydroxy-3-aryloyloxyglobyl) (2-methacryloyloxyethyl) ) diethylammonium hydroxide or its salt, (2-hydroxy-3-aryloyloxypropyl (2-acryloyloxyethyl) dimethylammonium hydroxide or its salt, methallyl (
2-methacryloyloxyethyl)dimethylammonium hydroxide is its salt.

Methallyl (2-methacryloyloxyethyl) diethylammonium hydroxide or its salt, methallyl (2-methacryloyloxyethyl) diethylammonium hydroxide or its salt;
(acryloyloxyethyl)dimethylammonium hydroxide or in situ, (vinylbenzyl)(methacryloyloxyethyl)dimethylammonium hydroxide or its salts.

(vinylbenzyl)(methacryloyloxyethyl)diethylammonium hydroxide or its salt, (vinylbenzyl)(acryloyloxyethyl)dimethylammonium hydroxide or its salt, (2-hydroxy-
3-methacryloyloxypropyl)(vinylbenzyl)dimethylammonium hydroxide, 9 is its salt, (2
-hydroxy-3-methacryloyloxypropyl) (
(vinylbenzyl)diethylammonium hydroxide or its salt, (2-hydroxy-3-acryloyloxypropyl)(vinylbenzyl)dimethylammonium hydroxide or its [,(2-hydroxy-3-aryloyloxy) Propyl)(vinylbenzyl)dimethylammonium hydroxide or its salt, (2-hydroxy-
3-aryloyloxypropyl)(vinylbenzyl)diethylammonium hydroxide or its salt, (methallyl)(vinylbenzyl)dimethylammonium hydroxide or its salt, Cmethallyl)(vinylbenzyl)diethylammonium Hydroxide or its salt, divinyl type monomer) Dimethylammonium hydroxide or its salt, di(vinylbenzyl)diethylammonium hydroxide or its salt, etc. Furthermore, chlorine ions are anions that form salts with these ammoniums.

These include bromine ions, iodine ions, fluoride ions, acetate ions, nitrate ions, sulfate ions, phosphate ions, etc. An example of a divinyl monomer having a pyridinium group in the molecule is N-(methallyl)-4-vinylpyridinium hydroxide or a salt thereof.

N-(methallyl)-2-vinylpyridinium hydroxide or a salt thereof, N-(vinylbenzyl)-4-vinylpyridinium hydroxide or a salt thereof.

Examples include N-(vinylbenzyl)-1-vinylpyridinium hydroxide or a salt thereof. These anions form salts with pyridinium.

Chlorine ion, bromide ion, hydrogen ion, fluoride ion, acetate ion, nitrate ion, sulfate ion.

There are phosphate ions, etc. These divinyl type monomers having a quaternary ammonium group or pyridinium group in their molecules form a crosslinking bond by copolymerizing with a cationic monomer or a nonionic monomer.

It has excellent stain resistance, water resistance, and organic solvent resistance, as well as long-term stability and reliability.

In the present invention, as the silicone resin for forming the retaining skin, for example, a condensation polymerization type (hydroxyl group-containing) silicone resin and an addition polymerization type silicone resin, each alone or a mixture thereof, can be used. When forming these silicone resin protective films, it is desirable to keep the formation temperature at 150C or less.With this temperature condition, the structural properties of the latex film will not deteriorate, and (9) the film itself will not deteriorate due to heat. Does not occur.

As such a silicone resin, -5t-ORTh
Typical examples include those obtained by reacting siloxanes having reactive groups such as siloxanes in the presence of a catalyst to increase the molecular weight or crosslinking them to form a rubber.

The main components are α,ω-dihydroxypolydimethylsiloxane and vinyltrimethoxysilane.

Further, as the addition polymerization type silicone resin, a commercially available product such as KE109 manufactured by Shin-Etsu Silicone Co., Ltd., or α.

A material whose main components are ω-divinyldimethylpolysiloxane and human misilyldimethylpolysiloxane can be used.

The thickness of such a protective film is not particularly limited, but from the viewpoint of the responsiveness of the humidity sensor, it is desirable to set it to %20 μm or less.

A humidity sensor according to an embodiment of the present invention is obtained as follows. First, the Km pole 5 is mounted on the insulating substrate 4, and a lead wire is connected to the connection terminal 7 at the end of the electric wire 5. After forming the substrate of the humidity-sensitive element in this manner, a moisture-sensitive material dispersion is applied onto the tX substrate. The moisture-sensitive material dispersion is a latex in which particles of a moisture-sensitive material copolymerized with the above-mentioned vinyl monomer are dispersed. Methods of applying this latex include spraying, brushing, and dipping.

Spinner coating 4. It is selected appropriately depending on the viscosity, substrate area, coating amount, production, etc. After applying the latex, the substrate is allowed to dry. Drying causes the latex particles to stick together, forming a #- film. Drying is performed by ventilation using dry air or nitrogen. According to this drying method, the latex particles themselves and the coating 4 formed from the particles are not destroyed.

A film of silicone resin is applied onto the moisture-sensitive film obtained as described above. The method of applying the silicone resin is appropriately selected depending on spraying, paulownia coating, dipping, spinner coating, viscosity, substrate rkJ product, coating amount, and production amount. Conditions for drying or curing the silicone resin face to be applied are appropriately selected depending on the properties of the resin. However, conditions that require long periods of time at high temperatures are unfavorable.
This is because it causes thermal deterioration of the moisture sensitive film. 180
Thermal history should be limited to less than 10 hours at temperatures below 0.

In addition to the above features, the humidity sensor of the present invention has the advantage that it is easy to convert detected humidity into an electrical signal and is reliable.

Since the resistance value of the latex film moisture-sensitive material used in the humidity sensor of the present invention is low, the humidity sensor using this material picks up noise, which, like dust, affects the conductivity of the moisture-sensitive material. Even if substances adhere to the film, humidity can be detected with high accuracy.

Since the core of each particle constituting the moisture-sensitive material has low hygroscopicity, the film does not swell or contract, and it is less likely to peel off from the substrate. Also, due to the protective film on the surface of the moisture-sensitive material, it becomes less susceptible to the effects of water droplets, cooking oil vapor, cigarette smoke, etc. In addition, long-term stability and high reliability of the moisture-sensitive element can be achieved.

(51) Methyl methacrylate (MMA) α2 mol,
methylenebisacrylamide (MBA) 0.01 mol,
0.1 mol of 2-meth-2lyloyloxyethyltrimethylammonium iodide (METMAI) as a cationic columnar additive (also serves as an emulsifier) and 0.1 mol of azobisisobutyramidine hydrochloride (AIBA) as a polymerization initiator.
．． 001 mol in aoomi aqueous medium under i1 elemental atmosphere.

Emulsion copolymerization was carried out at 60C for 10 hours with high speed stirring. As a result, a stable latex was obtained in which MMA units and NBA units were contained within one particle and trimethylammonium groups, which were cationic groups, were present on the surface. This latex was purified by dialysis for 2 months using a cellophane dialysis tube to remove low molecular weight impurities.

: 1 for nine latex electrode coatings obtained for $1 purpose
This will be explained with reference to Figure 'fjjI'r. That is, FIG. 2 is a plan view showing a specific example of a humidity sensor having a comb-shaped gold electrode, and FIG. 3 is an AA/cross-sectional view of the g1f sensor shown in FIG. 5 is a gold electrode, 3 is a moisture sensitive material, 7Fi! J-wire connection terminal.

Reference numeral 6 indicates a protective film, and the moisture-sensitive material, ie, latex, obtained by the above synthesis reaction is shown in FIGS. 2 and 3.
A Km cloth was placed on an aluminum substrate provided with comb-shaped gold electrodes 5, and dried to obtain an electrical resistance humidity sensor (control 1). The weight of the moisture-sensitive latex film formed at this time was 5 mg.

(b) Ho #! Reapply to On the surface of the moisture-sensitive latex film in the above humidity chamber.

α, <l1l-dihydroxypolydimethylsiloxane 9
A 5-layer lid part, a condensation type silicone resin containing 6 parts by weight of vinyl trimethoxy 7 run and 0.3 parts by weight of dibutyltin dioctoate was warmed with a spinner, and heated in a room! After reacting at 50% relative humidity for 100 hours, the mixture was cured at 100 tr for 2 hours to obtain a humidity sensor (Example 1) provided with a 5-am thick protective film.

The humidity sensitivity characteristics of the humidity sensors of Example 1 and Control 1 were investigated. In other words, Figure 4 shows the relative humidity (%) of the humidity sensor (horizontal axis).
This is a graph showing the relationship between electrical resistance (Ω) (vertical axis), A(-·-) indicates the case of Example 1, and B(-0-) indicates the case of Control 1.

As is clear from the graph in FIG. 4, there was almost no difference between the two, and it was confirmed that the formation of the wire retention film had no effect on the moisture sensitivity characteristics.

Next, in order to examine the long-term stability, reliability, and environmental resistance of the g1 degree sensor of the present invention, various harsh conditions were applied to the humidity sensor, and changes in the electrical resistance of the humidity sensor were read. The results were compared to the initial value, and the amount of change was calculated as relative humidity using the human curve in Figure 4. Conditions for accelerated testing considered.

Also, the results of Example 1 and Control 1 are summarized in a table.

Incidentally, when the relative humidity change amount is positive, it means that the electrical resistance value has changed due to the acceleration test. Also 1
All of the results in the table were obtained by measuring how the electrical resistance value of the humidity sensor at a relative humidity of 50% changes by conducting a severe test.

I have organized the calculations based on this IIt bill versus humidity. The measurement points are the average values of 10 samples.

It is said that humans are able to sensually sense and detect humidity changes when the amount of change in relative humidity exceeds (0% RH).There are 4 individual differences, but the amount of change in relative humidity is 7 to 8.
The amount of change in %RH is the boundary value of what humans can or cannot perceive. Therefore, the drift limit value of the humidity sensor (
Range in which the humidity sensitivity characteristics of the humidity sensor can be determined to be stable)
Therefore, it is considered appropriate to certify 7 to 8% RH.

Example 2 and Control 2 (Synthesis of ml moisture-sensitive polymer and application to electrode 500 ml of 2-methacryloyloxyethyldimethyloctylammonium chloride α1 mop as a cation columnar material)
Dissolved in distilled water of J and 0.2 m of methyl methacrylate as a non-ionic column and 0.2 m of methyl methacrylate as a non-ionic divinyl type).
0.02m0J was added, and then azobisisobutyladendine hydrochloride α003m0J was added as a polymerization initiator,
A copolymerization reaction was carried out in the same manner as in Example 1. As a result, particles of the copolymer crosslinked with ethylene glycol dimethacrylate were uniformly dispersed in water, and a latex-like liquid was obtained. After dialysis and purification of this solution.

It was coated on an insulating substrate with comb-shaped electrodes as shown in FIGS. 2 and 3 and dried to obtain a humidity sensor (control 2).

The weight of the moisture sensitive material film at this time was approximately 1 mg.

(Import & - film coating added to the surface of the moisture sensitive latex film of the g1 degree sensor mentioned above)
Composite silicone resin (manufactured by Shin-Etsu Silicone Co., Ltd.)

KE109) was applied using a spinner and cured for 2 hours at S 100r to obtain a humidity sensor (Example 2) provided with a 5 μm thick protective film.

Humidity sensitivity characteristics of the humidity sensors of Example 2 and Control 2 'frII. In other words, Figure 5 shows the relative humidity (%) of the humidity sensor (
This is a graph showing the relationship between electrical resistance (g) (horizontal axis) and electrical resistance (g) (vertical axis), where A (-・-) indicates the case of Example 2, and B (-〇-) indicates the case of Control 2. .

As is clear from the graph in FIG. 5, Ks and #1 did not change much, and it was confirmed that the formation of the retention film had no effect on the moisture sensitivity characteristics.

Next, in the same manner as in Example 1, the humidity sensors of Example 2 and Control 2 were left under harsh environmental conditions, the change in electrical resistance was measured, and the change in relative humidity was calculated using the results shown in Figure 5. Converted.

The results are summarized in the table above.

these. Let's die, let's die, let's die, 8ヮ. ,
・The temperature sensor has been placed under harsh environments such as factory air.

Characteristics are stable. That is, it can be seen that the humidity sensor has excellent environmental resistance and high axis reliability.

Example 3 (1) Production of moisture-sensitive polymer and application to electrodes Vinylbenzyltrimethylammonium chloride 0.2 m o , , e and divinyl-type upper nomatocyte having a quaternary ammonium group in one molecule were used as cationic polymers. Dissolve 0.01 m0J of sivinylbenzyldimethylammonium chloride in 500 m of distilled water, add 2 moJ of styrene Q as a non-ionic columnar to the water bath solution, then add 1 moJ of azobisisobutyramidine hydrochloride as an initiator. 0.004m0J t-addition, under nitrogen atmosphere, 60C
The copolymerization reaction was carried out by stirring at high speed for 10 hours. This one 1
In this case, vinylpencyltrimethylammonium chloride and divinylbenzyldimethylammonium chloride acted as emulsifiers in emulsion polymerization, and as a result, crosslinked copolymer particles were uniformly dispersed in water, resulting in a latex-like liquid.

After dialysis and purification of Jin's Enemy, it is applied onto an insulating substrate with a comb-shaped electrode as shown in Figures 2 and 3.

It was dried to obtain a humidity sensor (Example 3). The weight of the moisture-sensitive film at this time was about 1 mg.

(b) Preservative film coating Surface K of the moisture-sensitive latex film of the humidity sensor.

α,ω-divinyldimethylpolysiloxane (molecule 134
．． 000395 parts by weight, 3 parts by weight of hydrosilyldimethylpolysiloxane (molecular weight 1,354), and 0 platinum catalyst
．． Addition polymerization type silicone resin containing 08 parts by weight was applied using a spinner and heated at 1001:' for 2 hours.

A humidity sensor (Example 4) with a 5 μm thick koji protective film was obtained by reacting at 150C for 1 hour.

The table above shows the results of converting the change in electrical resistance into the amount of change in relative humidity when this humidity sensor was left in the same harsh environment as in Example 1.

Example 4 (Preparation of Xun Moisture Sensitive Polymer and Application thereof Soom4 water contains 0.2 mol of acrylonitrile as a hydrophobic monomer, 0.02 mol of allyl glycidyl ether and 0.02 mol of aminoethyl methacrylate as crosslinking agents)
0.01 mol of hydroxyethyl methacrylate as a monomer giving a graft point and 0.001 mol of azobisisobutylazidine tjA acid salt as a polymerization initiator, the liquid temperature was set to 70C, and the mixture was heated in an atmosphere of 1 for 10 hours. The copolymerization reaction and the crosslinking reaction were carried out simultaneously without high-speed stirring. Next, 0.01 mole of ceric ammonium nitrate as a graft polymerization initiator and 0.1 mole of 2-methacryloyloxyethyltrimethylammonium bromide as a cationic monomer to be grafted were added to the latex thus obtained, and the liquid temperature was raised to 50C. Grafting reaction 21 was carried out under a nitrogen atmosphere for 6 hours with high speed stirring. As a result, a latex in which fine particles having one surface layer coated with a cationic polymer were dispersed was obtained. This latex was applied to a comb-shaped electrode as shown in FIGS. 2 and 3 and dried in the same manner as in Example 1 to obtain an ffi degree sensor.

(b) Application of a protective film The humidity sensor obtained as described above was heated to 50C using a silicone resin (I! KE102RTV manufactured by Etsu Silicone Co., Ltd.).
(added with CatalYIt RH),
Pull it up and cure it at 90C for 4 hours.

An ff1f sensor (Example 4) provided with a protective film having a thickness of 7 μm was obtained. Changes in electrical resistance when this humidity sensor is left in the same harsh environment as in Example 1.

The results are shown in the table above when converted to the amount of change in relative humidity.

Example 5 (Synthesis of sensitive layer polymer and coating on electrode 0.1 m of 2-methacryloyloxytinyldimethylbutylammonium bromide and 500 m of OA as cationic monomers)
To J dissolved in distilled water, 0.2 m OJ of methyl methacrylate as a nonionic monomer and 0.01 mol of divinylbenzene as a crosslinking agent were added, and then azobisisobutyramidine hydrochloride was added as a polymerization initiator. α00
3 m0J was added and a co-1 reaction was carried out in the same manner as in Example 1. As a result, a latex-like liquid in which co-mono-coalized particles were uniformly dispersed in water was obtained. After dialysis and purification of this solution, OH-type strongly alkaline anion crosslinking resin ([)
Using 8BR-P (manufactured by ow Chemicl 1),
The counter ion was converted from bromide ion to OH'''.

The latex-like liquid treated in this way is shown in Figure 2.
A humidity sensor was obtained by coating and drying a comb-shaped electrode as shown in FIG. The humidity of the moisture-sensitive film at this time was 2 mg.

(b) Application of a protective film Addition polymerization type silicone resin (manufactured by Shin-Etsu Silicone Co., Ltd.) is applied to the surface of the moisture-sensitive latex film of the above-mentioned humidity sensor.

Apply KE106LTV) with a spinner, 100C, 2
After curing for a period of time, a protective film with a thickness of 4 μm was formed. The humidity sensor finally obtained in this way was
Electrical resistance change t when left in the same harsh environment as l
``aThe results converted to the amount of change in relative humidity are shown in the table marked @.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of a humidity sensor according to an embodiment of the present invention, Fig. 2 is a plan view of a humidity sensor according to an embodiment of the present invention, and Fig. 3 is a cross-sectional view taken along line AA' in Fig. 2. , FIG. 4, and FIG. 5 are relative humidity electrical resistance characteristic diagrams of a humidity sensor according to an embodiment of the present invention. 1... Core, 2... Surface layer, 3... Moisture sensitive film, 4...
...Insulating base 7 Figure 53 Figure 4 Relative humidity Osu Figure 55 Relative humidity (γ・)

Claims (1)

[Claims] 1. A humidity sensor equipped with a moisture-sensitive material whose electrical resistance value changes in response to changes in external humidity, wherein the moisture-sensitive material comprises a hydrophobic core and a cationic surface covering the core. 1. A humidity sensor comprising an aggregate of fine particles comprising a layer, and a moisture-retaining film of silicone resin is formed on the upper surface of the moisture-sensitive material. 2. The humidity sensor according to claim 1, wherein the fine particles constituting the moisture sensitive material are latex particles obtained by a copolymerization reaction of a cationic vinyl monomer and a nonionic vinyl monomer. 1. The fine particles constituting the moisture sensitive material are latex particles obtained by a copolymerization reaction of a cationic vinyl monomer, a nonionic vinyl monomer, and a crosslinking material monomer containing a vinyl group. Humidity senna listed. 4. After synthesizing latex particles consisting of a core of a compound exhibiting hydrophobicity and a surface layer of a compound covering the core and having a cationic group in an aqueous solution, the latex was provided with a pair of electrodes. It is coated on an insulating substrate to form an aggregate film of latex particles that connects the electrode, and then dried. After that, a silicone resin varnish is applied to the surface of the latex particle aggregate film, and then dried or reacted and preserved.
A method for manufacturing a humidity sensor characterized by forming a film.