US4473813A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Humidity sensor with improved protective layering
Assignee: Hitachi Ltd
•
Filing: 1982-09-28
•
Granted: 1984-09-25
•
Expires: 2002-09-28
Abstract
Abstract The invention relates to a humidity sensor of electric resistance type whose electric resistance changes in accordance with an ambient humidity, characterized by a protective film of silicone resin provided on the surface of a humidity-sensitive material, and to a method for preparing the same. The protective film of silicone resin is formed by applying a varnish of siloxanes to the humidity-sensitive material and subjecting the varnish to reaction. The varnish can be of one-part curing system or two-part curing system, and desirably the reaction of siloxanes is a cross-linking reaction. The formed protective film is not influenced by swelling or shrinking of the humidity-sensitive material, and is prevented from flowing off due to a temperature rise, or from deposition of dusts, etc.
Inventors
- 👤 Noriyuki Kinjo
- 👤 Shuichi Ohara
- 👤 Toru Sugawara
- 👤 Shigeki Tsuchitani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:56
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/121
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
59 words
A humidity sensor having a humidity-sensitive material, the electric resistance of the material being changeable in accordance with a change in an ambient humidity, which comprises a protective film of cross-linked silicone resin being provided on the surface of the humidity-sensitive material, the humidity-sensitive material being selected from the group consisting of a hydrophilic polymer compound and a polyelectrolyte.
Claim 2
Dependent Claim
59 words
A humidity sensor having a humidity-sensitive material, the electric resistance of the material being changeable in accordance with a change in an ambient humidity, which comprises a protective film of cross-linked silicone resin being provided on the surface of the humidity-sensitive material, the humidity-sensitive material being selected from the group consisting of a hydrophilic polymer compound and a polyelectrolyte.
Claim 3
Dependent Claim
31 words
The humidity sensor according to claim 1, wherein the humidity-sensitive material is an aggregate of fine particles, each consisting of a hydrophobic nucleus and a cationic surface layer covering the nucleus.
Claim 4
Dependent Claim
31 words
The humidity sensor according to claim 2, wherein the fine particles constituting the humidity-sensitive material are latex particles obtained by copolymerization of a cationic vinyl monomer and a non-ionic vinyl monomer.
Claim 5
Dependent Claim
37 words
The humidity sensor according to claim 2, wherein the fine particles constituting the humidity-sensitive material are latex particles obtained by copolymerization of a cationic vinyl monomer, a non-ionic vinyl monomer, and a cross-linking monomer containing vinyl groups.
Claim 6
Dependent Claim
42 words
The humidity sensor according to claim 1, 2, 3 or 4, wherein the cross-linked silicone resin is a reaction product of siloxanes themselves having at least one reactive group selected from ##STR4## where R represents a hydrogen atom or an alkyl group.
Claim 7
Dependent Claim
84 words
A humidity sensor which comprises an insulating substrate, a pair of electrodes provided on the insulating substrate, connection terminals for connecting the ends of the electrodes to lead wires, and a humidity-sensitive material film provided on the surface of the insulating substrate provided with the electrodes, the improvement in combination therewith comprising a protective film of silicone resin as a reaction product of siloxanes themselves having at least one reactive group selected from ##STR5## where R represents a hydrogen atom or an alkyl group.
Claim 8
Dependent Claim
84 words
A humidity sensor which comprises an insulating substrate, a pair of electrodes provided on the insulating substrate, connection terminals for connecting the ends of the electrodes to lead wires, and a humidity-sensitive material film provided on the surface of the insulating substrate provided with the electrodes, the improvement in combination therewith comprising a protective film of silicone resin as a reaction product of siloxanes themselves having at least one reactive group selected from ##STR5## where R represents a hydrogen atom or an alkyl group.
Claim 9
Dependent Claim
25 words
The humidity sensor according to claim 6, wherein the humidity-sensitive material is selected from the group consisting of a hydrophilic polymer compound and a polyelectrolyte.
Claim 10
Dependent Claim
17 words
The humidity sensor according to claim 6, wherein the protective film of the silicone resin is cross-linked.
Claim 11
Dependent Claim
34 words
The humidity sensor according to claim 6, 7 or 8, wherein the humidity-sensitive material is an aggregate of fine particles, each consisting of a hydrophobic nucleus and a cationic surface layer covering the nucleus.
Claim 12
Dependent Claim
31 words
The humidity sensor according to claim 9, wherein the fine particles constituting the humidity-sensitive material are latex particles obtained by copolymerization of a cationic vinyl monomer and a non-ionic vinyl monomer.
Claim 13
Dependent Claim
37 words
The humidity sensor according to claim 10, wherein the fine particles constituting the humidity-sensitive material are latex particles obtained by copolymerization of a cationic vinyl monomer, a non-ionic vinyl monomer, and a cross-linking monomer containing vinyl groups.
Claim 14
Dependent Claim
69 words
A humidity sensor having a humidity-sensitive material extending between a pair of electrodes, the electric resistance of the material being changeable in accordance with a change in an ambient humidity, which comprises a protective film of cross-linked silicone resin provided on the surface of the humidity-sensitive material, whereby a protective film that will not flow even if exposed to high humidity, for a long period of time, is provided.
Claim 15
Dependent Claim
69 words
A humidity sensor having a humidity-sensitive material extending between a pair of electrodes, the electric resistance of the material being changeable in accordance with a change in an ambient humidity, which comprises a protective film of cross-linked silicone resin provided on the surface of the humidity-sensitive material, whereby a protective film that will not flow even if exposed to high humidity, for a long period of time, is provided.
Claim 16
Dependent Claim
23 words
The humidity sensor according to claim 1, 6 or 12, wherein said protective film has a thickness of not more than 20 μm.
Claim 17
Dependent Claim
33 words
The humidity sensor according to claim 1, 8 or 12, wherein said protective film is formed by curing a varnish coating of silicone resin at a temperature of not more than 180° C.
Claim 18
Dependent Claim
20 words
The humidity sensor according to claim 14, having been subjected to an aging treatment at high humidity after the curing.
Claim 19
Dependent Claim
34 words
The humidity sensor according to claim 1 or 12, wherein said cross-linked silicone resin is formed from a polycondensation type silicone resin having hydroxyl groups, an addition polymerization type silicone resin, or mixtures thereof.
Claim 20
Dependent Claim
19 words
The humidity sensor according to claim 1, 6 or 12, wherein said protective film is in a rubbery state.
References Cited (Backward Citations)
US3073161A
Cited
US3167734A
Cited
US3559456A
Cited
US3864659A
Cited
US3848218A
Cited
US3891958A
Cited
JPS5020781A
Cited
US4167725A
Cited
JPS5480191A
Cited
US4386336A
Cited
US4245069A
Cited
GB2071323A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-25 | 1988-03-26 | 1988-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-25 | 1992-03-26 | 1992-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-25 | 1996-03-26 | 1996-09-25 | $7700.00 | Window Closed / Lapsed |