US3975473A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for production of cellular thermoplastic bodies
Assignee: Union Carbide Corp
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Filing: 1975-06-04
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Granted: 1976-08-17
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Expires: 1995-06-04
Abstract
Abstract A process is provided for the production of a cellular thermoplastic body, wherein solid thermoplastic material is melted under pressure in an extruder, a gaseous blowing agent is injected into the molten thermoplastic material under pressure and said molten thermoplastic material and gaseous blowing agent is passed to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, and wherein said gaseous blowing agent is metered at sonic velocity at a point upstream of the injection of said gaseous blowing agent into said molten thermoplastic material.
Inventors
- 👤 William P. Mulvaney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:18
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/20; B29C44/32; B29C44/322; B29C44/34; B29C44/3442; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/13
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
101 words
In the process for the production of a cellular thermoplastic body, wherein solid thermoplastic material is melted under pressure in an extruder, a gaseous blowing agent is injected into the molten thermoplastic material under pressure and admixed and through the mixture of said molten thermoplastic material and said gaseous blowing agent is passed to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, the improvement which comprises metering said gaseous blowing agent at sonic velocity at a point upstream of the injection of said blowing agent into said molten thermoplastic material.
Claim 2
Dependent Claim
101 words
In the process for the production of a cellular thermoplastic body, wherein solid thermoplastic material is melted under pressure in an extruder, a gaseous blowing agent is injected into the molten thermoplastic material under pressure and admixed and through the mixture of said molten thermoplastic material and said gaseous blowing agent is passed to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, the improvement which comprises metering said gaseous blowing agent at sonic velocity at a point upstream of the injection of said blowing agent into said molten thermoplastic material.
Claim 3
Dependent Claim
34 words
The process in accordance with claim 1, wherein said mixture of molten thermoplastic material and injected blowing agent are passed through a wire coating die and onto a conductor to form a coated conductor.
Claim 4
Dependent Claim
30 words
The process in accordance with claim 1, wherein said thermoplastic material is selected from the group consisting of polyethylene, polypropylene, and polystyrene and said gaseous blowing agent is gaseous nitrogen.
Claim 5
Dependent Claim
63 words
The process in accordance with claim 1, wherein said gaseous blowing agent is metered through a device having a constricting orifice which causes the gas velocity of said gaseous belowing agent to be sonic through the throat of said orifice and thereby effecting injection of said gas into said molten thermoplastic material at a controllable uniform rate unaffected by the material back pressure.
Claim 6
Dependent Claim
106 words
In the process for the production of a cellular thermoplastic body, wherein solid thermoplastic material is melted under pressue in an extruder, a soluble gaseous blowing agent is injected into the molten thermoplastic material under pressure and admixed therewith the mixture of said molten thermoplastic material and the solubilized gaseous blowing agent is passed from said extruder to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, the improvement which comprises metering said gaseous blowing agent at sonic velocity at a point upstream of said extruder prior to injection of said blowing agent into said extruder.
Claim 7
Dependent Claim
106 words
In the process for the production of a cellular thermoplastic body, wherein solid thermoplastic material is melted under pressue in an extruder, a soluble gaseous blowing agent is injected into the molten thermoplastic material under pressure and admixed therewith the mixture of said molten thermoplastic material and the solubilized gaseous blowing agent is passed from said extruder to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, the improvement which comprises metering said gaseous blowing agent at sonic velocity at a point upstream of said extruder prior to injection of said blowing agent into said extruder.
Claim 8
Dependent Claim
34 words
The process in accordance with claim 5, wherein said mixture of molten thermoplastic material and injected blowing agent are passed through a wire coating die and onto a conductor to form a coated conductor.
Claim 9
Dependent Claim
30 words
The process in accordance with claim 5, wherein said thermoplastic material is selected from the group consisting of polyethylene, polypropylene, and polystyrene and said gaseous blowing agent is gaseous nitrogen.
Claim 10
Dependent Claim
61 words
The process in accordance with claim 5, wherein said gaseous blowing agent is metered through a device having a constricting orifice which causes the gas velocity of said gaseous blowing agent to be sonic through the throat of said orifice and thereby effecting injection of said gas into said extruder at a controllable uniform rate unaffecteed by the extruder back pressure.
Claim 11
Dependent Claim
120 words
The process for the production of a cellular thermoplastic body comprising melting under pressure in an extruder a solid thermoplastic material, metering a stream of gaseous blowing agent at sonic velocity prior to injection under pressure into the molten thermoplastic material to provide a mixture of said gaseous blowing agent in said molten thermoplastic material, passing said mixture of molten thermoplastic material and said gaseous blowing agent to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, and varying the pressure of said stream of gaseous blowing agent at a point upstream of the point of metering to obtain the desired variation in density of the expanded cellular thermoplastic material.
Claim 12
Dependent Claim
120 words
The process for the production of a cellular thermoplastic body comprising melting under pressure in an extruder a solid thermoplastic material, metering a stream of gaseous blowing agent at sonic velocity prior to injection under pressure into the molten thermoplastic material to provide a mixture of said gaseous blowing agent in said molten thermoplastic material, passing said mixture of molten thermoplastic material and said gaseous blowing agent to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, and varying the pressure of said stream of gaseous blowing agent at a point upstream of the point of metering to obtain the desired variation in density of the expanded cellular thermoplastic material.
Claim 13
Dependent Claim
34 words
The process in accordance with claim 9, wherein said mixture of molten thermoplastic material and gaseous blowing agent is passed through a wire coating die and onto a conductor to form a coated conductor.
Claim 14
Dependent Claim
30 words
The process in accordance with claim 9, wherein said thermoplastic material is selected from the group consisting of polyethylene, polypropylene and polystyrene and said gaseous blowing agent is gaseous nitrogen.
Claim 15
Dependent Claim
63 words
The process in accordance with claim 9, wherein said gaseous blowing agent is metered through a device having a constricting orifice which causes the gas velocity of said gaseous blowing agent to be sonic through the throat of said orifice and thereby effecting injection of said gas into said molten thermoplastic material at a controllable uniform rate unaffected by the material back pressure.
Claim 16
Dependent Claim
124 words
The process for the production of a cellular thermoplastic body comprising melting under pressure in an extruder a solid thermoplastic material, metering a stream of gaseous blowing agent at sonic velocity prior to injection under pressure into the molten thermoplastic material to provide a mixture of said gaseous blowing agent in said molten thermoplastic material, passing said mixture of molten thermoplastic material and said gaseous blowing agent from said extruder to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, and varying the pressure of said stream of gaseous blowing agent at a point upstream of the point of metering to obtain the desired variation in density of the expanded cellular thermoplastic plastic material.
Claim 17
Dependent Claim
124 words
The process for the production of a cellular thermoplastic body comprising melting under pressure in an extruder a solid thermoplastic material, metering a stream of gaseous blowing agent at sonic velocity prior to injection under pressure into the molten thermoplastic material to provide a mixture of said gaseous blowing agent in said molten thermoplastic material, passing said mixture of molten thermoplastic material and said gaseous blowing agent from said extruder to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, and varying the pressure of said stream of gaseous blowing agent at a point upstream of the point of metering to obtain the desired variation in density of the expanded cellular thermoplastic plastic material.
Claim 18
Dependent Claim
35 words
The process in accordance with claim 13, wherein said mixture of molten thermoplastic material and said gaseous blowing agent is passed through a wire coating die and onto a conductor to form a coated conductor.
Claim 19
Dependent Claim
30 words
The process in accordance with claim 13, wherein said thermoplastic material is selected from the group consisting of polyethylene, polypropylene and polystyrene and said gaseous blowing agent is gaseous nitrogen.
Claim 20
Dependent Claim
61 words
The process in accordance with claim 13, wherein said gaseous blowing agent is metered through a device having a constriction orifice which causes the gas velocity of said gaseous blowing agent to be sonic through the throat of said orifice and thereby effecting injection of said gas into said extruder at a controllable uniform rate unaffected by the extruder back pressure.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-17 | 1980-02-16 | 1980-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-17 | 1984-02-16 | 1984-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-17 | 1988-02-16 | 1988-08-17 | $7700.00 | Window Closed / Lapsed |