US4333898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a foamed plastic
Assignee: KM Kabelmetal AG
•
Filing: 1978-10-26
•
Granted: 1982-06-08
•
Expires: 1998-10-26
Abstract
Abstract An elastomeric or thermoplastic polymer, such as polyethylene, is mixed with silane for grafting onto the polyethylene; after grafting the material is extruded around a cable, a conductor, tubing or the like, but just prior to extrusion moist nitrogen is forced into the extruder so that the material will expand to foam, the cells being filled with moist gas so that the cell walls crosslink to stabilize the resulting foam sheath.
Inventors
- 👤 Hans-Martin Schmidtchen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 01:52
CPC Classifications
C; C08; C08L; C08L43/00; C08L43/04; B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/50; B29C44/507; H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/441; H01B3/46; B29K; B29K2023/00; B29K2105/00; B29K2105/24; B29L; B29L2031/00; B29L2031/34; B29L2031/3462; Y; Y10; Y10S; Y10S264/00; Y10S264/18
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
106 words
In a method of making a cellular, polymeric product, wherein a silane compound is grafted upon a thermoplastic or elastomeric material to permit crosslinking in the presence of moisture, after the grafting-on of the silane, the grafted material being in a fluid state, the improvement of introducing into the grafted material from the outside pressurized, moist gas as a foaming agent, subsequent to grafting, while the grafted material is still in the fluid state, for obtaining and producing cells in the material, the cell walls being exposed to the moisture in the gas and begin crosslinking, and immediately thereafter shaping the material into the desired product.
Claim 2
Dependent Claim
106 words
In a method of making a cellular, polymeric product, wherein a silane compound is grafted upon a thermoplastic or elastomeric material to permit crosslinking in the presence of moisture, after the grafting-on of the silane, the grafted material being in a fluid state, the improvement of introducing into the grafted material from the outside pressurized, moist gas as a foaming agent, subsequent to grafting, while the grafted material is still in the fluid state, for obtaining and producing cells in the material, the cell walls being exposed to the moisture in the gas and begin crosslinking, and immediately thereafter shaping the material into the desired product.
Claim 3
Dependent Claim
23 words
Method in accordance with claim 1, wherein the polymeric material comprises an olefin polymer or copolymer, or an elastomer or a thermoplastic rubber.
Claim 4
Dependent Claim
44 words
Method in accordance with claim 1 or 2, wherein the shaping step comprises extruding a coating or sheath around elongated stock such as an electric cable, lead or conductor, or a tube, the moist gas being introduced into an extruder at an excess pressure.
Claim 5
Dependent Claim
25 words
Method in accordance with claim 1, or 2, wherein the moist gas is comprised of a mixture of water vapor and of an inert gas.
Claim 6
Dependent Claim
11 words
Method in accordance with claim 4, said inert gas being nitrogen.
Claim 7
Dependent Claim
22 words
Method in accordance with claim 1, and including heating the moist gas to a temperature above room temperature prior to said introducing.
Claim 8
Dependent Claim
81 words
In a method of coating elongated stock, by means of a cross-linked foam of thermoplastic or elastomeric material, wherein a silane compound has been grafted upon the material, and wherein subsequently the material is extruded onto and around the stock, the improvement of introducing a pressurized, moist gas into the material just prior to extrusion for expanding the material in order to obtain cells and for beginning cross-linking of the cell walls by exposure to the moisture of the blowing gas.
Claim 9
Dependent Claim
81 words
In a method of coating elongated stock, by means of a cross-linked foam of thermoplastic or elastomeric material, wherein a silane compound has been grafted upon the material, and wherein subsequently the material is extruded onto and around the stock, the improvement of introducing a pressurized, moist gas into the material just prior to extrusion for expanding the material in order to obtain cells and for beginning cross-linking of the cell walls by exposure to the moisture of the blowing gas.
Claim 10
Dependent Claim
25 words
Method in accordance with claim 6 or 7, wherein the moist gas is comprised of a mixture of water vapor and of an inert gas.
Claim 11
Dependent Claim
11 words
Method in accordance with claim 8, said inert gas being nitrogen.
References Cited (Backward Citations)
US2948665A
Cited
US2960482A
Cited
US3017371A
Cited
GB1234034A
Cited
GB1286460A
Cited
GB1408154A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-07 | 1985-12-07 | 1986-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-07 | 1989-12-07 | 1990-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-07 | 1993-12-07 | 1994-06-08 | $7700.00 | Window Closed / Lapsed |