JPS6237339B2 - - Google Patents
Info
- Publication number
- JPS6237339B2 JPS6237339B2 JP57054569A JP5456982A JPS6237339B2 JP S6237339 B2 JPS6237339 B2 JP S6237339B2 JP 57054569 A JP57054569 A JP 57054569A JP 5456982 A JP5456982 A JP 5456982A JP S6237339 B2 JPS6237339 B2 JP S6237339B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- moisture
- resin coating
- polymer resin
- humidity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000002952 polymeric resin Substances 0.000 claims description 38
- 239000011248 coating agent Substances 0.000 claims description 37
- 238000000576 coating method Methods 0.000 claims description 37
- 229920003002 synthetic resin Polymers 0.000 claims description 37
- 238000001514 detection method Methods 0.000 claims description 19
- 239000003792 electrolyte Substances 0.000 claims description 14
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 14
- 239000000758 substrate Substances 0.000 claims description 11
- 238000010521 absorption reaction Methods 0.000 claims description 6
- 239000010410 layer Substances 0.000 description 34
- 229920000642 polymer Polymers 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 239000004372 Polyvinyl alcohol Substances 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 239000012528 membrane Substances 0.000 description 5
- 230000008961 swelling Effects 0.000 description 5
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- -1 cyclic acid anhydrides Chemical class 0.000 description 3
- 230000009477 glass transition Effects 0.000 description 3
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 3
- 239000005518 polymer electrolyte Substances 0.000 description 3
- SZNYYWIUQFZLLT-UHFFFAOYSA-N 2-methyl-1-(2-methylpropoxy)propane Chemical compound CC(C)COCC(C)C SZNYYWIUQFZLLT-UHFFFAOYSA-N 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229920001477 hydrophilic polymer Polymers 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004043 responsiveness Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229920001567 vinyl ester resin Polymers 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- KXJGSNRAQWDDJT-UHFFFAOYSA-N 1-acetyl-5-bromo-2h-indol-3-one Chemical compound BrC1=CC=C2N(C(=O)C)CC(=O)C2=C1 KXJGSNRAQWDDJT-UHFFFAOYSA-N 0.000 description 1
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 239000001856 Ethyl cellulose Substances 0.000 description 1
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 244000126211 Hericium coralloides Species 0.000 description 1
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 description 1
- 239000004354 Hydroxyethyl cellulose Substances 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 108010020346 Polyglutamic Acid Proteins 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 239000001913 cellulose Chemical class 0.000 description 1
- 229920002678 cellulose Chemical class 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229920001249 ethyl cellulose Polymers 0.000 description 1
- 235000019325 ethyl cellulose Nutrition 0.000 description 1
- 229920000370 gamma-poly(glutamate) polymer Polymers 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 description 1
- 125000005395 methacrylic acid group Chemical group 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000005486 organic electrolyte Substances 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920005735 poly(methyl vinyl ketone) Polymers 0.000 description 1
- 229920001495 poly(sodium acrylate) polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 238000007127 saponification reaction Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Chemical compound [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000002277 temperature effect Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 229920006163 vinyl copolymer Polymers 0.000 description 1
- 239000004711 α-olefin Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/121—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid for determining moisture content, e.g. humidity, of the fluid
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Non-Adjustable Resistors (AREA)
Description
この発明は湿度変化を抵抗変化として検出する
感湿抵抗体に関し、特に寿命特性にすぐれた感湿
抵抗体に関するものである。
感湿抵抗体には、塩化リチウム（Licl）などの
電解質を絶縁性基板の表面に塗布した、いわゆる
ダンモア型のものや、有機の高分子電解質膜から
なるものなどがある。
このうち前者のものは、塩化リチウムが吸湿し
て電離することにより、検出電極間のインピーダ
ンスが変化するタイプのものである。
また、後者のものは高分子電解質膜が有する吸
湿性とイオン導電性を利用したものであり、これ
も検出電極間のインピーダンスが変化する特性を
有するものである。
これらの感湿抵抗体はいずれも感湿材料が有す
る親水性のために、高湿度状態や結露状態になる
と水分を含んで溶解してしまい、耐水性に乏しい
ことから、動作安定性に欠けるというものであつ
た。
かかる欠点を改善する目的で、親水性高分子ま
たは高分子電解質膜を架橋するという試みが考え
られる。しかし架橋構造を構成することによつて
耐水性を持たせることができるとしても、応答性
が低下し、機能の低下を招くことになり、好まし
い解決策といえるものではない。
したがつて、この発明は湿度の検出特性を損う
ことなく、安定な機能を有する感湿抵抗体を提供
することを目的とする。
この発明を要約すれば、絶縁性基板の上に形成
された一対の検出電極と、この検出電極を覆つて
形成された感湿膜とからなり、該感湿膜はポリビ
ニルアルコール系重合体と電解質とを含む第１層
の高分子樹脂被膜とその表面を覆う吸湿性を有す
る第２層の高分子樹脂被膜との一体構造からな
り、第２層の高分子樹脂被膜が第１層の高分子樹
脂被膜より吸湿による膨潤度が小さいことを特徴
とする感湿抵抗体である。
この発明の詳細とその他の目的、特徴は以下に
行う説明において明らかとならう。
第１図はこの発明にかかる感湿抵抗体の一例を
示す概略平面図、第２図は第１図Ａ―Ａ線断面図
である。
図において明らかなように、１はアルミナ、ジ
ルコニアなどからなる絶縁性基板、２，３は絶縁
性基板１の上に形成された検出電極であり、図示
したものは電極指が交互に交叉しているくし歯状
になつている。４は感湿膜を示し、検出電極２，
３を含む領域にこの検出電極２，３を覆うように
形成されている。この感湿膜４は特に第２図にお
いて明らかにされているように、ポリビニルアル
コール系重合体と電解質とを含む第１層の高分子
樹脂被膜５と、この被膜５を覆う吸湿性を有する
第２層の高分子樹脂被膜６との一体構造からなる
ものであり、第２層の高分子樹脂被膜６は第１層
の高分子樹脂被膜５より吸湿による膨潤度が小さ
いという特徴を有する。このような特徴は後述す
るところから明らかなようにすぐれた効果をもた
らすものである。なお、７，８はリード線で検出
電極２，３から導出されている。
上記した構成において、ポリビニルアルコール
系重合体には次のようなものがある。
酢酸ビニル、その他の各種ビニルエステル類
の重合体、およびこれらの共重合体を完全ケン
化または部分ケン化して得られたもの。
酢酸ビニル、その他の各種ビニルエステル類
と各種不飽和単量体、たとえば、α―オレフイ
ン類、塩化ビニル、アクリロニトリル、アクリ
ルアミド、アクリル酸エステル類、メタクリル
酸エステル類を共重合させた共重合体のケン化
物。
こうしたポリビニルアルコール系重合体の環
状酸無水物でエステル化したポリビニルアルコ
ール共重合体やカルボキシル基変性されたポリ
ビニルアルコール系重合体。
また、電解質とは水分吸着によつてイオン解離
を生じ、イオン伝導性を与える物質であり、無
機、有機電解質のものを含む。これにはたとえ
ば、塩化ナトリウム、酢酸ナトリウム、ポリアク
リル酸ソーダ、ポリグルタミン酸ソーダなどがあ
る。
さらに、第２層を構成する吸湿性を有する高分
子樹脂被膜としては、次のようなものがある。
デアセテルセルロース、メチルセルロース、
エチルセルロース、ヒドロキシエチルセルロー
ス、カルボキシメチルロース、シアノエチルセ
ルロースなどのセルロース誘導体。
ポリ酢酸ビニル、ポリ塩化ビニル、ポリメチ
ルビニルケトン、ポリビニルイソブチルエーテ
ルなどの各種ポリビニルア重合体。
ポリブチルアルコール、ポリメチルアリルア
ルコールなどのポリアルキルアルコール系高分
子。
ヒドロキシアルキルアクリレート、ポリアル
キルアクリル酸の部分エステル化物、ポリメチ
ルメタクリレートなどのポリアクリル系重合
体。
アクリロニトリル。
エポキシ系高分子。
この発明にかかる感湿抵抗体を作成するには、
まずアルミナなどの絶縁性基板の上に、検出電極
を覆うように電解質を含むポリビニルアルコール
系重合体を膜状に塗布印刷などの手段で付与す
る。次いでこれを自然乾燥または熱処理すること
によつて乾燥する。さらにこの上に吸湿性を有す
る高分子樹脂のペーストを膜状に塗布、印刷など
の手段で付与し、こののち加熱することによつて
得られる。
上記した構成からなるこの発明の感湿抵抗体は
次のような効果をもたらすものである。
第１層の高分子樹脂被膜はポリビニルアルコー
ル系重合体と電解質とを含むものからなるが、構
造的に見れば均一ではなく、ポリビニルアルコー
ル系重合体のうち部分的に結晶化した微小の繊維
粒状部が非晶質部分を介して存在している構造を
とる。したがつて、第１層においては繊維粒状部
の粒界に形成される非晶質部のマイクロチヤンネ
ルが形成されている。一方、電解質の多くはこの
非晶質部に多く存在しており、吸湿に伴なうイオ
ン伝導はこのマイクロチヤンネルを通して行われ
ていると推定される。この第１層のみでも相対湿
度によつて電極間のインピーダンスは変化する
が、表面に水滴が付着すれば、ただちに電解質が
溶解し、電極間インピーダンスが増大することと
なり、感湿抵抗体として使用できなくなる。
ところが、この発明によれば、このような第１
層の高分子樹脂被膜の上に第２層の高分子樹脂被
膜を形成して一体構造とし、この第２層の高分子
樹脂被膜の吸湿による膨潤度を第１層の高分子樹
脂被膜より小さくして、上記した欠点を改善した
ものである。
つまり、第２層の高分子樹脂被膜は第１層の高
分子樹脂被膜の繊維粒状部による表面の凹凸にも
とづき、大きな接合面積が得られ、強固な接合状
態が実現されている。そしてかかる層状一体構造
において、第１層の高分子樹脂被膜よりも第２層
の高分子樹脂被膜の吸湿による膨潤度を小さくす
れば、第１層の高分子樹脂被膜に含まれている電
解質が水中へ溶出する量はほとんど無視できる程
度に押えることができ、電極間インピーダンスの
変動は全く生じないことが判明した。
当然のことながら、感湿膜を構成する第１層の
高分子樹脂被膜および第２層の高分子樹脂被膜の
それぞれの膜厚によつて応答性や感度が変わるた
め、所定の特性を得るためにその膜厚を制御する
必要があることはいうまでもない。
また、この発明にかかる感湿抵抗体は、電解質
濃度を変えることによつて、相対湿度―抵抗特性
を変えることができる。ちなみに、電解質濃度が
少ない領域では、高湿度で抵抗値が急激に変化す
る湿度スイツチング素子として有用な感湿抵抗体
が得られる。
さらに、ポリビニルアルコール系重合体のケン
化度を変えることによつて、膨潤度を変えること
ができるので、感湿特性の調整が可能である。ま
たポリビニルアルコール系重合体の重合度等によ
つてガラス転移点を変えることができる。このガ
ラス転移点を変えることによつて、感湿抵抗体の
温度特性を変えることができ、かかる特徴を利用
すれば、使用可能な温度範囲に調整することがで
きるようになり、従来より使用することがむつか
しいとされていたポリビニルアルコール系重合体
を感湿抵抗体に実用化することができる。
以上のように、感湿膜を層状構造にすることに
よつて、従来親水性高分子樹脂を用いた感湿抵抗
体では困難であつた耐水特性の大幅な改善を実現
することができる。
以下にこの発明を具体的な実施例にもとづいて
詳細に説明する。
実施例
絶縁性基板としてアルミナ基板を準備し、この
アルミナ基板の上に検出電極として、電極の間隔
が300μｍ、対向電極長が48mmの金からなるくし
歯状の検出電極を形成した。
次いで、第１表に示すように、第１層の高分子
樹脂被膜を構成する各ペーストを検出電極を覆う
ようにアルミナ基板の上にそれぞれ塗布し、この
塗布膜を乾燥した。
こののち、同じく第１表に示すように、第２層
の高分子樹脂被膜を構成する各ペーストを上記第
１層の高分子樹脂被膜を覆うように塗布し、150
℃で加熱処理した。さらに検出電極にリード線を
取り付けて各感湿抵抗体を得た。
The present invention relates to a humidity-sensitive resistor that detects changes in humidity as changes in resistance, and particularly to a humidity-sensitive resistor with excellent longevity characteristics. Moisture-sensitive resistors include the so-called Dunmore type, in which an electrolyte such as lithium chloride (LiCl) is coated on the surface of an insulating substrate, and those made of an organic polymer electrolyte membrane. Among these, the former type is a type in which the impedance between the detection electrodes changes as lithium chloride absorbs moisture and ionizes. The latter utilizes the hygroscopicity and ionic conductivity of the polymer electrolyte membrane, and also has the characteristic that the impedance between the detection electrodes changes. Due to the hydrophilic nature of the moisture-sensitive materials, all of these moisture-sensitive resistors absorb moisture and dissolve in high humidity or dew conditions, resulting in poor water resistance and poor operational stability. It was hot. In order to improve these drawbacks, an attempt may be made to crosslink hydrophilic polymers or polymer electrolyte membranes. However, even if water resistance can be imparted by constructing a crosslinked structure, the responsiveness will be lowered and the functionality will be lowered, so this cannot be said to be a preferable solution. Therefore, an object of the present invention is to provide a humidity-sensitive resistor that has stable functions without impairing its humidity detection characteristics. To summarize this invention, it consists of a pair of detection electrodes formed on an insulating substrate and a moisture-sensitive film formed to cover the detection electrodes, and the moisture-sensitive film is made of a polyvinyl alcohol-based polymer and an electrolyte. It has an integral structure of a first layer of polymer resin coating containing a first layer of polymer resin and a second layer of hygroscopic polymer resin coating that covers the surface thereof, and the second layer of polymer resin coating has a first layer of polymer resin. This is a moisture-sensitive resistor characterized by a lower degree of swelling due to moisture absorption than a resin coating. Details and other objects and features of the invention will become apparent from the description that follows. FIG. 1 is a schematic plan view showing an example of a moisture-sensitive resistor according to the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. As is clear from the figure, 1 is an insulating substrate made of alumina, zirconia, etc., and 2 and 3 are detection electrodes formed on the insulating substrate 1. In the illustrated one, the electrode fingers are alternately crossed. It has a comb-tooth shape. 4 indicates a moisture-sensitive membrane, and detection electrodes 2,
The detection electrodes 2 and 3 are formed in a region including the detection electrodes 2 and 3. As shown in FIG. 2, this moisture-sensitive membrane 4 includes a first layer of polymer resin coating 5 containing a polyvinyl alcohol polymer and an electrolyte, and a moisture-absorbing second layer covering this coating 5. It has an integral structure with two layers of polymeric resin coating 6, and the second layer of polymeric resin coating 6 has a characteristic that the degree of swelling due to moisture absorption is smaller than that of the first layer of polymeric resin coating 5. These features bring about excellent effects, as will be clear from what will be described later. Note that 7 and 8 are lead wires led out from the detection electrodes 2 and 3. In the above configuration, the polyvinyl alcohol polymers include the following. Products obtained by completely saponifying or partially saponifying polymers of vinyl acetate, other vinyl esters, and copolymers thereof. A copolymer made by copolymerizing vinyl acetate, other vinyl esters, and various unsaturated monomers, such as α-olefins, vinyl chloride, acrylonitrile, acrylamide, acrylic esters, and methacrylic esters. monster. Polyvinyl alcohol copolymers esterified with cyclic acid anhydrides of such polyvinyl alcohol polymers and carboxyl group-modified polyvinyl alcohol polymers. Further, an electrolyte is a substance that causes ionic dissociation by moisture adsorption and provides ionic conductivity, and includes inorganic and organic electrolytes. These include, for example, sodium chloride, sodium acetate, sodium polyacrylate, and sodium polyglutamate. Further, examples of the hygroscopic polymer resin film constituting the second layer include the following. deacetercellulose, methylcellulose,
Cellulose derivatives such as ethylcellulose, hydroxyethylcellulose, carboxymethylulose, and cyanoethylcellulose. Various polyvinyl urethane polymers such as polyvinyl acetate, polyvinyl chloride, polymethylvinyl ketone, polyvinyl isobutyl ether, etc. Polyalkyl alcohol polymers such as polybutyl alcohol and polymethylallyl alcohol. Polyacrylic polymers such as hydroxyalkyl acrylate, partially esterified polyalkyl acrylic acid, and polymethyl methacrylate. Acrylonitrile. Epoxy polymer. To create the moisture-sensitive resistor according to this invention,
First, a film of polyvinyl alcohol-based polymer containing an electrolyte is applied onto an insulating substrate such as alumina so as to cover the detection electrode by means such as coating printing. This is then dried by air drying or heat treatment. Furthermore, it is obtained by applying a paste of a hygroscopic polymer resin in the form of a film by means such as coating or printing, and then heating it. The moisture-sensitive resistor of the present invention having the above-described structure brings about the following effects. The first layer of polymer resin coating is made of a material containing a polyvinyl alcohol polymer and an electrolyte, but it is not uniform from a structural point of view. It has a structure in which the two parts exist through an amorphous part. Therefore, in the first layer, microchannels of amorphous portions are formed at the grain boundaries of the fiber granular portions. On the other hand, most of the electrolyte is present in this amorphous region, and it is presumed that ionic conduction accompanying moisture absorption takes place through these microchannels. Even with this first layer alone, the impedance between the electrodes changes depending on the relative humidity, but if water droplets adhere to the surface, the electrolyte will immediately dissolve and the impedance between the electrodes will increase, making it impossible to use it as a humidity-sensitive resistor. It disappears. However, according to this invention, such a first
A second layer of polymer resin coating is formed on top of the first layer of polymer resin coating to form an integral structure, and the swelling degree of the second layer of polymer resin coating due to moisture absorption is smaller than that of the first layer of polymer resin coating. This improves the above-mentioned drawbacks. In other words, the second layer of polymer resin coating has a large bonding area based on the surface irregularities caused by the fiber granules of the first layer of polymer resin coating, and a strong bonding state is realized. In such a layered integral structure, if the degree of swelling due to moisture absorption of the second layer polymer resin coating is made smaller than that of the first layer polymer resin coating, the electrolyte contained in the first layer polymer resin coating can be reduced. It was found that the amount eluted into water could be suppressed to an almost negligible level, and no fluctuations in inter-electrode impedance occurred. Naturally, the responsiveness and sensitivity vary depending on the thickness of the first layer of polymer resin coating and the second layer of polymer resin coating that make up the moisture-sensitive film, so it is necessary to obtain the desired characteristics. Needless to say, it is necessary to control the film thickness. Moreover, the relative humidity-resistance characteristics of the humidity-sensitive resistor according to the present invention can be changed by changing the electrolyte concentration. Incidentally, in a region where the electrolyte concentration is low, a humidity-sensitive resistor that is useful as a humidity switching element whose resistance value changes rapidly at high humidity can be obtained. Furthermore, by changing the degree of saponification of the polyvinyl alcohol polymer, the degree of swelling can be changed, so the moisture sensitivity characteristics can be adjusted. Further, the glass transition point can be changed by changing the degree of polymerization of the polyvinyl alcohol polymer. By changing this glass transition point, the temperature characteristics of the moisture-sensitive resistor can be changed, and by utilizing this characteristic, it becomes possible to adjust the temperature within the usable temperature range, making it possible to change the temperature characteristics of the moisture-sensitive resistor. Polyvinyl alcohol-based polymers, which have been thought to be difficult to use, can now be put to practical use in moisture-sensitive resistors. As described above, by forming the moisture-sensitive film into a layered structure, it is possible to achieve a significant improvement in water resistance, which has been difficult with conventional moisture-sensitive resistors using hydrophilic polymer resins. The present invention will be explained in detail below based on specific examples. Example An alumina substrate was prepared as an insulating substrate, and a comb-shaped detection electrode made of gold was formed on the alumina substrate as a detection electrode with an electrode interval of 300 μm and a counter electrode length of 48 mm. Next, as shown in Table 1, each paste constituting the first layer of polymer resin coating was applied onto the alumina substrate so as to cover the detection electrode, and this coating film was dried. Thereafter, as shown in Table 1, each paste constituting the second layer of polymer resin coating was applied to cover the first layer of polymer resin coating.
Heat treated at ℃. Furthermore, lead wires were attached to the detection electrodes to obtain each moisture-sensitive resistor.
【表】【table】
【表】
第３図〜第７図は上記した各実施例により得ら
れた感湿抵抗体の相対湿度―抵抗特性図を示した
ものである。
第３図は試料１―１、試料１―２の特性図であ
る。
第４図は試料２―１、試料２―２、試料２―３
の特性図である。
第５図は試料３―１、試料３―２の特性図であ
る。
第６図は試料４―１、試料４―２、試料４―３
の特性図である。
第７図は試料５―１、試料５―２、試料５―
３、試料５―４の特性図である。
図中の番号はいずれも試料番号と一致する。
第３図から明らかなように、この実施例によれ
ば高湿度で急激に抵抗値が低下する特性を有し、
特定の湿度でスイツチング特性を有する感湿抵抗
体として利用することができる。
また、第４図からポリビニルアルコール系重合
体の種類を変えることによつて、スイツチング特
性を変えることができることがわかる。
また、第５図からは電解質濃度を変えることに
よつて、特性を変化させることができると理解し
うる。
また、第６図は第１層の高分子樹脂被膜を覆う
第２層の高分子樹脂被膜の種類を変えた感湿抵抗
体の特性を示したものである。第１層の高分子樹
脂被膜が同じ種類のものであれば、異なる第２層
の高分子樹脂被膜を用いても特性に大幅な変化の
ないことがわかる。
また、第７図によれば、電解質の種類を変える
ことによつて特性を変えられることが伺える。
次に上記した各実施例で得られた各感湿抵抗体
について、水中30秒、乾燥10分を１サイクルとし
てこれを1000サイクル繰り返えし、その後相対湿
度90％における抵抗値を測定した。第２表はその
結果を示したもので、相対湿度90％における初期
抵抗値も併せて示した。[Table] FIGS. 3 to 7 show relative humidity-resistance characteristic diagrams of the humidity-sensitive resistors obtained in each of the above-mentioned Examples. FIG. 3 is a characteristic diagram of Sample 1-1 and Sample 1-2. Figure 4 shows sample 2-1, sample 2-2, and sample 2-3.
FIG. FIG. 5 is a characteristic diagram of Sample 3-1 and Sample 3-2. Figure 6 shows sample 4-1, sample 4-2, and sample 4-3.
FIG. Figure 7 shows sample 5-1, sample 5-2, sample 5-
3. Characteristic diagram of sample 5-4. All numbers in the figure correspond to sample numbers. As is clear from FIG. 3, this example has the characteristic that the resistance value decreases rapidly at high humidity.
It can be used as a humidity-sensitive resistor that has switching characteristics at a specific humidity. Furthermore, from FIG. 4, it can be seen that the switching characteristics can be changed by changing the type of polyvinyl alcohol polymer. Further, from FIG. 5, it can be understood that the characteristics can be changed by changing the electrolyte concentration. Moreover, FIG. 6 shows the characteristics of moisture-sensitive resistors in which the type of the second layer of polymer resin coating covering the first layer of polymer resin coating is changed. It can be seen that if the first layer polymer resin coating is of the same type, there is no significant change in the characteristics even if a different second layer polymer resin coating is used. Moreover, according to FIG. 7, it can be seen that the characteristics can be changed by changing the type of electrolyte. Next, each humidity-sensitive resistor obtained in each of the above-mentioned Examples was subjected to 1000 cycles of 30 seconds in water and 10 minutes in drying, and then the resistance value at 90% relative humidity was measured. Table 2 shows the results, and also shows the initial resistance value at 90% relative humidity.
【表】
第２表からこの発明にかかる感湿抵抗体は抵抗
値の変化が小さく、耐水性にすぐれたものである
ことがわかる。
比較例として、高分子樹脂被膜からなる表面層
を形成していない感湿抵抗体について同様に試験
を行つたところ、１サイクルの試験ですでに抵抗
値が１桁以上増大し、特性の劣化ははなはだしい
ものであつた。
また、試料番号２―２において、ガラス転移点
が２℃と５℃のアクリル変性ポリビニルアルコー
ルのものと用い、湿度―抵抗特性の温度効果につ
いてそれぞれ測定した結果、相対湿度―抵抗特性
の温度変化率はそれぞれ１％RH／℃、0.5％
RH／℃であつた。このことからこの発明にかか
る感湿抵抗体は温度変化に対して相対湿度―抵抗
特性の変化の小さいものと云える。
また、試料２―２の感湿抵抗体を用い、相対湿
度60％、70％、80％、90％の各条件に感湿抵抗体
を設置し、約３カ月経過したのちの抵抗値を測定
したところ、第８図のような結果であつた。
図から明らかなように、一定条件の湿度状態下
に設置しておいても、ほとんど抵抗値の変化が見
られず、安定した湿度検出特性を有しているもの
と云える。
以上この発明にかかる感湿抵抗体によれば、良
好な耐水性を有するとともに、経時変化も小さい
という特徴を有するものであり、実用上有用なも
のである。[Table] It can be seen from Table 2 that the moisture-sensitive resistor according to the present invention has a small change in resistance value and excellent water resistance. As a comparative example, when a similar test was conducted on a moisture-sensitive resistor without a surface layer made of a polymer resin film, the resistance value increased by more than an order of magnitude after one cycle of the test, and there was no deterioration of the characteristics. It was extremely difficult. In addition, in sample number 2-2, we used acrylic-modified polyvinyl alcohol with glass transition points of 2°C and 5°C to measure the temperature effect on humidity-resistance characteristics, and found that the temperature change rate of relative humidity-resistance characteristics are 1%RH/℃ and 0.5%, respectively.
It was RH/℃. From this, it can be said that the humidity-sensitive resistor according to the present invention exhibits small changes in relative humidity-resistance characteristics with respect to temperature changes. In addition, using the humidity-sensitive resistor of sample 2-2, the humidity-sensitive resistor was installed under conditions of relative humidity of 60%, 70%, 80%, and 90%, and the resistance value was measured after about 3 months. The results were as shown in Figure 8. As is clear from the figure, even when installed under constant humidity conditions, there is almost no change in resistance value, and it can be said that the device has stable humidity detection characteristics. As described above, the moisture-sensitive resistor according to the present invention has the characteristics of good water resistance and little change over time, and is useful in practice.
第１図はこの発明にかかる感湿抵抗体の一例を
示す概略平面図、第２図は第１図のＡ―Ａ線断面
図、第３〜第７図は相対湿度―低抗特性図、第８
図は抵抗値の経時変化特性を示す図である。
１……絶縁性基板、２，３……検出電極、４…
…感湿膜、５……第１層の高分子樹脂被膜、６…
…第２層の高分子樹脂被膜。
FIG. 1 is a schematic plan view showing an example of a humidity-sensitive resistor according to the present invention, FIG. 2 is a sectional view taken along line A--A in FIG. 1, and FIGS. 3 to 7 are relative humidity-low resistance characteristic diagrams. 8th
The figure is a diagram showing the temporal change characteristics of resistance value. 1... Insulating substrate, 2, 3... Detection electrode, 4...
...Moisture sensitive film, 5...First layer polymer resin coating, 6...
...Second layer polymer resin coating.
Claims (1)
と、この検出電極を覆つて形成された感湿膜とか
らなり、該感湿膜はポリビニルアルコール系重合
体と電解質とを含む第１層の高分子樹脂被膜とそ
の表面を覆う吸湿性を有する第２層の高分子樹脂
被膜との一体構造からなり、第２層の高分子樹脂
被膜が第１層の高分子樹脂被膜より吸湿による膨
潤度が小さいことを特徴とする感湿抵抗体。1 Consisting of a pair of detection electrodes formed on an insulating substrate and a moisture-sensitive film formed to cover the detection electrodes, the humidity-sensitive film has a first layer containing a polyvinyl alcohol polymer and an electrolyte. It has an integral structure of a polymer resin coating and a second layer of hygroscopic polymer resin coating that covers the surface, and the second layer of polymer resin coating swells more than the first layer of polymer resin coating due to moisture absorption. Moisture-sensitive resistor characterized by low humidity.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57054569A JPS58171657A (en) | 1982-03-31 | 1982-03-31 | Moisture sensitive resistor |
| US06/477,408 US4442422A (en) | 1982-03-31 | 1983-03-21 | Humidity sensitive resistor |
| GB08307942A GB2119099B (en) | 1982-03-31 | 1983-03-23 | Humidity sensitive resistor |
| DE19833311047 DE3311047A1 (en) | 1982-03-31 | 1983-03-25 | MOISTURE SENSITIVE RESISTANCE |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57054569A JPS58171657A (en) | 1982-03-31 | 1982-03-31 | Moisture sensitive resistor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58171657A JPS58171657A (en) | 1983-10-08 |
| JPS6237339B2 true JPS6237339B2 (en) | 1987-08-12 |
Family
ID=12974319
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57054569A Granted JPS58171657A (en) | 1982-03-31 | 1982-03-31 | Moisture sensitive resistor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58171657A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9459233B2 (en) * | 2012-06-25 | 2016-10-04 | Steris Corporation | Amperometric gas sensor |
| US10782261B2 (en) * | 2014-03-25 | 2020-09-22 | The Procter & Gamble Company | Apparatus for sensing environmental humidity changes |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5528505A (en) * | 1978-08-16 | 1980-02-29 | Tdk Corp | Magnetic recording medium |
| JPS561579A (en) * | 1979-06-18 | 1981-01-09 | Shunpei Yamazaki | Semiconductor device |
-
1982
- 1982-03-31 JP JP57054569A patent/JPS58171657A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58171657A (en) | 1983-10-08 |
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