US4975329A
Expired / Lapsed
US
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Coextruded, biaxially oriented multilayer film
Assignee: Hoechst AG
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Filing: 1988-11-21
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Granted: 1990-12-04
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Expires: 2008-11-21
Abstract
Abstract A coextruded, biaxailly oriented multilayer film comprises a base layer comprising an extremely pure raw material and outer layer. It is suitable for use as an electrically insulating film, as a dielectric in an electrical capacitor, and has improved dielectrical properties for this purpose. The base layer and the outer layer or layers contain propylene polymer on one or both sides and stabilizers for propylene polymers. The raw material for the base layer has an idealized thermal oxidation temperature in the range of 260 DEG to 300 DEG C., preferably in the range 260 DEG to 280 DEG C., and the raw material for the outer layer or layers has an idealized thermal oxidation temperature in the region of 240 DEG to 300 DEG C., preferably in the range 240 DEG to 270 DEG C. The multilayer film as a whole has an idealized thermal oxidation temperature in the range 250 DEG to 290 DEG C., in paticular in the range 250 DEG to 275 DEG C. The content of organic neutralizing agents, in particular calcium stearate, in the raw materials is less than or equal to 100 ppm.
Inventors
- 👤 Lothar Bothe
- 👤 Guenther Crass
- 👤 Gunter Schloegl
- 👤 Thomas Wilheim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:48
CPC Classifications
B; B32; B32B; B32B7/00; B32B7/02; B32B7/027; B32B27/00; B32B27/06; B32B27/08; B32B15/00; B32B15/04; B32B15/08; B32B15/085; B32B27/18; B32B27/32; C; C08; C08L; C08L23/00; C08L23/02; C08L23/10; C08L23/12; H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/14; H01G4/18; B32B2307/00; B32B2307/20; B32B2307/206; B32B2307/50; B32B2307/514; B32B2307/518; B32B2307/538; C08L23/04; C08L23/06; C08L23/08; C08L23/0807; C08L23/0815; C08L23/18; C08L23/20; C08L53/00; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678; Y10T428/31692; Y10T428/31855; Y10T428/31909; Y10T428/31913
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
142 words
A coextruded, biaxially oriented multilayer film comprising: (a) a base layer comprising an extremely pure raw material which comprises at least one propylene polymer and at least one stabilizer for propylene polymers, and (b) an outer layer on at least one side of said base layer, comprising a raw material which comprises at least one propylene polymer and at least one stabilizer for propylene polymers, wherein said base layer raw material has an idealized thermal oxidation temperature of between about 260 and 300° C., said outer layer raw material has an idealized thermal oxidation temperature of between about 240 and 300° C., and said multilayer film as a whole has an idealized thermal oxidation temperature of between about 250 and 290° C., and wherein said raw materials further comprise from 0 to about 100 ppm of at least one organic neutralizing agent.
Claim 2
Dependent Claim
142 words
A coextruded, biaxially oriented multilayer film comprising: (a) a base layer comprising an extremely pure raw material which comprises at least one propylene polymer and at least one stabilizer for propylene polymers, and (b) an outer layer on at least one side of said base layer, comprising a raw material which comprises at least one propylene polymer and at least one stabilizer for propylene polymers, wherein said base layer raw material has an idealized thermal oxidation temperature of between about 260 and 300° C., said outer layer raw material has an idealized thermal oxidation temperature of between about 240 and 300° C., and said multilayer film as a whole has an idealized thermal oxidation temperature of between about 250 and 290° C., and wherein said raw materials further comprise from 0 to about 100 ppm of at least one organic neutralizing agent.
Claim 3
Dependent Claim
27 words
A multilayer film as claimed in claim 1, wherein said base layer raw material has an idealized thermal oxidation temperature of between about 260 and 280° C.
Claim 4
Dependent Claim
27 words
A multilayer film as claimed in claim 1, wherein said outer layer raw material has an idealized thermal oxidation temperature of between about 240 and 270° C.
Claim 5
Dependent Claim
27 words
A multilayer film as claimed in claim 1, wherein said film as a whole has an idealized thermal oxidation temperature of between about 250 and 275° C.
Claim 6
Dependent Claim
22 words
A multilayer film as claimed in claim 1, wherein said film has an outer layer on each side of the base layer.
Claim 7
Dependent Claim
15 words
A multilayer film as claimed in claim 1, wherein said neutralizing agent comprises calcium stearate.
Claim 8
Dependent Claim
28 words
A multilayer film as claimed in claim 1, wherein the stabilizer content of said outer layer material is equal to the stabilizer content of said base layer material.
Claim 9
Dependent Claim
28 words
A multilayer film as claimed in claim 1, wherein the stabilizer content of said outer layer material is less than the stabilizer content of said base layer material.
Claim 10
Dependent Claim
33 words
A multilayer film as claimed in claim 8, wherein the stabilizer content of said outer layer material is less than about 50% by weight of the stabilizer content of said base layer material.
Claim 11
Dependent Claim
19 words
A multilayer film as claimed in claim 1, wherein said base and outer layer materials comprise extremely pure polypropylene.
Claim 12
Dependent Claim
26 words
A multilayer film as claimed in claim 1, wherein said base and outer layer materials comprise a polymer mixture of polypropylene with at least one polyolefin.
Claim 13
Dependent Claim
39 words
A multilayer film as claimed in claim 11, wherein said polyolefin comprises HDPE, LDPE, LLDPE or poly-4-methyl-1-pentene and the proportion of said polyolefin does not exceed about 15% by weight based on the total weight of the polymer mixture.
Claim 14
Dependent Claim
24 words
A multilayer film as claimed in claim 1, wherein said base and outer layer materials comprise a block copolymer comprising polypropylene and a comonomer.
Claim 15
Dependent Claim
34 words
A multilayer film as claimed in claim 13, wherein said comonomer comprises ethylene and the proportion of said comonomer does not exceed about 10% by weight based on the total weight of the copolymer.
Claim 16
Dependent Claim
24 words
A multilayer film as claimed in claim 1, wherein said base and outer layer materials comprise a random copolymer comprising polypropylene and a comonomer.
Claim 17
Dependent Claim
34 words
A multilayer film as claimed in claim 15, wherein said comonomer comprises ethylene and the proportion of said comonomer does not exceed about 10% by weight based on the total weight of the copolymer.
Claim 18
Dependent Claim
23 words
A multilayer film as claimed in claim 1, wherein said stabilizer comprises a thioether, a phosphonite, a phosphite, or a sterically hindered phenol.
Claim 19
Dependent Claim
22 words
A multilayer film as claimed in claim 17, wherein said sterically hindered phenol has a molecular weight greater than about 300 g/mol.
Claim 20
Dependent Claim
22 words
A multilayer film as claimed in claim 18, wherein said sterically hindered phenol has a molecular weight greater than about 700 g/mol.
Claim 21
Dependent Claim
29 words
A multilayer film as claimed in claim 1, wherein the residual ash content is less than about 50 ppm and the chlorine content is less than about 10 ppm.
Claim 22
Dependent Claim
23 words
A multilayer film as claimed in claim 1, wherein the total thickness of the multilayer film is between about 3 and 30 μm.
Claim 23
Dependent Claim
21 words
A multilayer film as claimed in claim 21, wherein each outer layer has a thickness of from 0.3 to 2.0 μm.
Claim 24
Dependent Claim
16 words
A multilayer film as claimed in claim 22, wherein each layer is of the same thickness.
Claim 25
Dependent Claim
26 words
A multilayer film as claimed in claim 22, wherein each outer layer surface has a roughness R z less than or equal to about 1.5 μm.
Claim 26
Dependent Claim
15 words
A multilayer film as claimed in claim 1, which further comprises an outer metal layer.
Claim 27
Dependent Claim
20 words
An electrical film capacitor, comprising two metallic electrode layers separated by an electrically insulating film as claimed in claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-03 | 1994-06-04 | 1994-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-03 | 1998-06-04 | 1998-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-03 | 2002-06-04 | 2002-12-04 | $7700.00 | Window Closed / Lapsed |