EP0371745A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Preparation of positive temperature coefficient compositions and their use in protection devices
Assignee: Daito Communication Apparatus Co Ltd
•
Filing: 1989-11-28
•
Granted: —
•
Expires: 2009-11-28
Abstract
Abstract A positive temperature coefficient composition comprising a dispersion of (i) carbon black which has been rendered porous or more porous by gaseous and/or vapour etching resulting in porous black having increased specific surface area, within (ii) polymer. Such compositions are useful in the construction of overcurrent protection devices, such as fuses, by virtue of their attractive position temperature coefficient (PTC) characteristics.
Inventors
- 👤 Akira Daito Communication App. Co. Ltd. Ueno
- 👤 Mayumi Daito Communication App. Co. Ltd. Takada
- 👤 Naoki Daito Communication App. Co. Ltd. Yamazaki
- 👤 Shoichi Daito Communication App. Co. Ltd. Sugaya
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 04:32
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/027; C; C08; C08K; C08K3/00; C08K3/02; C08K3/04; C08K7/00; C08K7/22; C08K7/24; C09; C09C; C09C1/00; C09C1/44; C09C1/48; C09C1/56; H01C7/13; C01; C01P; C01P2004/00; C01P2004/01; C01P2004/04; C01P2006/00; C01P2006/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
37 words
A positive temperature coefficient composition comprising a dispersion of (i) carbon black which has been rendered porous or more porous by gaseous and/or vapour etching resulting in porous black having increased specific surface area, within (ii) polymer.
Claim 2
Dependent Claim
37 words
A positive temperature coefficient composition comprising a dispersion of (i) carbon black which has been rendered porous or more porous by gaseous and/or vapour etching resulting in porous black having increased specific surface area, within (ii) polymer.
Claim 3
Dependent Claim
12 words
A composition as claimed in claim 1 wherein (ii) comprises crystalline polymer.
Claim 4
Dependent Claim
32 words
A composition as claimed in claim 1 or 2 wherein (ii) comprises one or more of : high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, fluorocarbon polymer and poly(ethylene terephthalate).
Claim 5
Dependent Claim
16 words
A composition as claimed in any preceding claim wherein (ii) consists essentially of high density polyethylene.
Claim 6
Dependent Claim
22 words
A composition as claimed in any preceding claim further comprising carbon black which has not been subjected to vapour or gaseous etching.
Claim 7
Dependent Claim
29 words
A composition as claimed in any preceding claim, wherein the carbon black has an increased specific surface area of at least 1.5 times its value prior to said etching.
Claim 8
Dependent Claim
19 words
A composition as claimed in any preceding claim, wherein said carbon black comprises oil furnace black(s) and/or lamp black(s).
Claim 9
Dependent Claim
20 words
A composition as claimed in any preceding claim, wherein the volume resistivity at 20°C is 0.4 to 150 ohm cm.
Claim 10
Independent Claim
44 words
A method of making a composition as claimed in any preceding claim, comprising (a) increasing porosity of (i) carbon black by gaseous and/or vapour etching thereof to increase its specific surface area, and (b) dispersing the porous black formed in (a) with (ii) polymer.
Claim 11
Dependent Claim
17 words
A method as claimed in claim 9, wherein the etching is carried out by steam and/or CO₂.
Claim 12
Dependent Claim
28 words
A method as claimed in claim 9 or 10, wherein the etching is carried out at a temperature above 700°C, preferably at a temperature of 706°C to 950°C.
Claim 13
Dependent Claim
43 words
Use of a composition as claimed in any one of claims 1 to 8, or as produced by a method as claimed in any one of claims 9 to 11, in the construction of a self-resetting overcurrent protection device, such as a fuse.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.