US4177446A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heating elements comprising conductive polymers capable of dimensional change
Assignee: Raychem Corp
•
Filing: 1977-03-09
•
Granted: 1979-12-04
•
Expires: 1997-03-09
Abstract
Abstract The invention relates to heating elements comprising conductive polymers which are capable of undergoing a change in dimension. The heating elements comprise a laminar member composed of a conductive polymer and two laminar electrodes connected directly or indirectly to opposite faces of the laminar member, and there are apertures, for example slits, passing through the thickness of the element so that at least one planar dimension of the element can be changed by changing the shape of the apertures. The apertures through the element facilitate its dimensional change. Preferably the laminar member exhibits PTC characteristics. The heating elements are particularly useful in the form of articles in which the element is attached to a heat-responsive sheet, for example a heat-recoverable polymeric film.
Inventors
- 👤 Stephen H. Diaz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 02:44
CPC Classifications
B; B29; B29C; B29C61/00; B29C61/06; B29C61/0608; B29C61/0625; B29C61/0616; H; H01; H01C; H01C7/00; H01C7/02; H01C7/027; H05; H05B; H05B3/00; H05B3/02; H05B3/06; H05B3/10; H05B3/12; H05B3/14; H05B3/146; B29K; B29K2995/00; B29K2995/0003; B29K2995/0005
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
142 words
A heating element which comprises: (A) a laminar member composed of a material which comprises an organic polymer and electrically conductive particles dispersed in the polymer in amount sufficient to render the member electrically conductive; and (B) a pair of laminar flexible electrodes which (i) are connected to opposite faces of said laminar member; (ii) are substantially coplanar with said laminar member; and (iii) are adapted to be connected to an external source of power to cause current to pass through said laminar member; said laminar member and laminar electrodes having a plurality of apertures through the thickness thereof, the apertures being in parallel rows and being of elongated closed cross-section and overlapping one another to permit at least one of the dimensions of the element in the plane thereof to be changed by a change in the shape of the apertures.
Claim 2
Dependent Claim
142 words
A heating element which comprises: (A) a laminar member composed of a material which comprises an organic polymer and electrically conductive particles dispersed in the polymer in amount sufficient to render the member electrically conductive; and (B) a pair of laminar flexible electrodes which (i) are connected to opposite faces of said laminar member; (ii) are substantially coplanar with said laminar member; and (iii) are adapted to be connected to an external source of power to cause current to pass through said laminar member; said laminar member and laminar electrodes having a plurality of apertures through the thickness thereof, the apertures being in parallel rows and being of elongated closed cross-section and overlapping one another to permit at least one of the dimensions of the element in the plane thereof to be changed by a change in the shape of the apertures.
Claim 3
Dependent Claim
19 words
An element according to claim 1 wherein said laminar member is composed of a material which exhibits PTC behavior.
Claim 4
Dependent Claim
19 words
An element according to claim 2 wherein said laminar member has an R 30 value of at least 6.
Claim 5
Dependent Claim
31 words
An element according to claim 2 wherein the organic polymer in said laminar member is a cross-linked crystalline polymer and the conductive particles in said laminar member are carbon black particles.
Claim 6
Dependent Claim
32 words
An element according to claim 1 wherein the electrodes are composed of a material which comprises an organic polymer and electrically conductive particles dispersed therein, and are coextensive with said laminar member.
Claim 7
Dependent Claim
51 words
An element according to claim 2 wherein the electrodes are coextensive with said laminar member and are composed of a material which comprises an organic polymer and electrically conductive particles dispersed therein and which exhibits PTC behavior with a switching temperature which is above the switching temperature of said laminar member.
Claim 8
Dependent Claim
25 words
An element according to claim 1 wherein the electrodes are composed of a material having a resistivity of less than 1 ohm.cm at room temperature.
Claim 9
Dependent Claim
12 words
An element according to claim 7 wherein the electrodes are of metal.
Claim 10
Dependent Claim
22 words
An element according to claim 2 wherein the electrodes are composed of a metal selected from the group aluminum, copper, and lead.
Claim 11
Dependent Claim
26 words
An element according to claim 8 wherein the electrodes are composed of a metal having a ductility at least as high as aluminium and are corrugated.
Claim 12
Dependent Claim
23 words
An element according to claim 1 wherein the faces of the electrodes remote from the laminar member are coated with an insulating material.
Claim 13
Dependent Claim
80 words
An element according to claim 2 which also comprises at least one intermediate layer which (a) exhibits constant wattage behavior at temperatures below the switching temperature of said laminar member; (b) is composed of a material which comprises an organic polymer and electrically conductive particles dispersed in the polymer in amount sufficient to render the member electrically conductive; (c) has a resistivity greater than 10 ohm.cm at room temperature; and (d) is interposed between the laminar member and an electrode.
Claim 14
Dependent Claim
29 words
An element according to claim 12 wherein said intermediate constant wattage layer exhibits PTC behavior with a switching temperature which is above the switching temperature of said laminar member.
Claim 15
Dependent Claim
53 words
An element according to claim 1 in which the apertures are a plurality of identical straight slits in parallel equally-spaced rows with the slits in adjacent rows overlapping each other, the length of each slit being at least 1/2 inch and from 5 to 20 times the distance between adjacent rows of slits.
Claim 16
Dependent Claim
23 words
An element according to claim 14 wherein the distance between the edges of adjacent slits is 1/10 178 inch (0.25 to 1.25 cm).
Claim 17
Dependent Claim
59 words
An element according to claim 1 at least one of whose planar dimensions can be changed at the melting point of the polymer by a percentage which is at least 30%, based on the original dimension, without complete rupture of the electrode at any point, the dimensional change being accomodated by a change in the shape of the apertures.
Claim 18
Dependent Claim
25 words
An element according to claim 16 whose resistance at room temperature does not change by more than 20% as a result of said dimensional change.
Claim 19
Dependent Claim
20 words
An element according to claim 1 wherein the laminar member has a resistivity greater than 10 ohm.cm at room temperature.
References Cited (Backward Citations)
GB1050386A
Cited
US2559077A
Cited
US3020378A
Cited
US3221145A
Cited
US3311862A
Cited
US3351882A
Cited
GB1167551A
Cited
US3387065A
Cited
US3375774A
Cited
US3551644A
Cited
US3793716A
Cited
GB1516874A
Cited
US4017715A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-03 | 1983-06-04 | 1983-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-03 | 1987-06-04 | 1987-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-03 | 1991-06-04 | 1991-12-04 | $7700.00 | Window Closed / Lapsed |