Patent EP0112003A1 successfully refreshed from Google Patents.
Patent EP0033587A1 successfully refreshed from Google Patents.
EP0033587A1
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EP
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Preparation of shaped crosslinked materials
Assignee: Uponor Wirsbo AB
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Filing: 1981-01-13
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Granted: —
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Expires: 2001-01-13
Abstract
Abstract A method and apparatus for the formation of shaped crosslinked polyolefinic materials by subjecting a crosslinkable polyolefinic material to a high pressure in a high pressure treatment zone (34), passing the material from said high pressure treatment zone to a relaxation and expansion zone at a temperature below that at which crosslinking takes place, and thereafter shaping and heating the material to a temperature above that at which crosslinking occurs and allowing the crosslinking reaction to proceed substantially to completion.
Inventors
- 👤 Friedrich Imgram
- 👤 Gerhard Suppanz
- 👤 Richard Massoth
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 17:20
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/78; B29C48/86; B29C48/865; B29C48/022; B29C48/03; B29C48/09; B29C48/30; B29C48/32; B29C48/36; B29C48/475; B29K; B29K2101/00; B29K2101/10; B29K2301/00; B29K2301/10
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
77 words
A process for the formation of shaped cross-linked polyolefinic materials which process comprises subjecting a crosslinkable polyolefinic material to high pressure in a high pressure treatment zone, passing said material from said high pressure treatment zone to a relaxation and expansion zone at a temperature below that at which crosslinking takes place, thereafter shaping and heating the material to a temperature above that at which crosslinking occurs and allowing the crosslinking reaction to proceed substantially to completion.
Claim 2
Dependent Claim
77 words
A process for the formation of shaped cross-linked polyolefinic materials which process comprises subjecting a crosslinkable polyolefinic material to high pressure in a high pressure treatment zone, passing said material from said high pressure treatment zone to a relaxation and expansion zone at a temperature below that at which crosslinking takes place, thereafter shaping and heating the material to a temperature above that at which crosslinking occurs and allowing the crosslinking reaction to proceed substantially to completion.
Claim 3
Dependent Claim
22 words
A process as claimed in claim 1 wherein the crosslinkable material is a mixture of a polyolefin and a crosslinking agent therefor.
Claim 4
Dependent Claim
19 words
A process as claimed in claim 2 wherein the polyolefin is polyethylene and the crosslinking agent is dicumyl peroxide.
Claim 5
Dependent Claim
21 words
A process as claimed in anyone of the preceding claims wherein the high pressure is in excess of a 1000 atmospheres.
Claim 6
Dependent Claim
22 words
A process as claimed in anyone of the preceding claims wherein the high pressure is generated by means of an excentre press.
Claim 7
Dependent Claim
71 words
A process as claimed in any preceding claim wherein the material is passed from the high pressure treatment zone to a relaxation and expansion zone through a breaker plate assembly which provides a back pressure for maintaining high pressure within said high pressure zone and at the same time causes or allows working of the material to further increase the temperature of the material passing into said relaxation and expansion zone.
Claim 8
Dependent Claim
68 words
A process as claimed in any preceding claim wherein the shaping and heating is effected in a heated die having at least two constrictions ! towards the feed end thereof under conditions such that the temperature is not increased above the crosslinking threshold temperature until the material is in the vicinity of the second constriction in the die whereby substantial cross- linking occurs downstream of said second constriction.
Claim 9
Dependent Claim
22 words
A process as claimed in any preceding claim wherein the die passage may be of generally annular cross-section to produce a tube.
Claim 10
Dependent Claim
32 words
A process as claimed in any preceding claim wherein the die passage may be provided with means at or towards the outlet thereof for maintaining a back pressure within said die passage.
Claim 11
Dependent Claim
20 words
A process as claimed in any preceding claim wherein the crosslinkable polyolefinic material includes a portion of lubricant and/or stabiliser.
Claim 12
Dependent Claim
82 words
An extruder for the continuous shaping of a crosslinkable material which extruder comprises means for subjecting a crosslinkable polyolefinic material to high pressure, a relaxation zone to which material passing from said high pressure zone is stressed relieved at a temperature below that at which substantial crosslinking of the material takes place and die means defining a shape to be imparted to the material in which the temperature of the material is increased to at least that at which cross- linking occurs.
Claim 13
Dependent Claim
82 words
An extruder for the continuous shaping of a crosslinkable material which extruder comprises means for subjecting a crosslinkable polyolefinic material to high pressure, a relaxation zone to which material passing from said high pressure zone is stressed relieved at a temperature below that at which substantial crosslinking of the material takes place and die means defining a shape to be imparted to the material in which the temperature of the material is increased to at least that at which cross- linking occurs.
Claim 14
Dependent Claim
19 words
An extruder as claimed in claim 11 wherein the die passage has an annular cross-section to produce a tube.
Claim 15
Dependent Claim
27 words
An extruder as claimed in claim 11 or claim 12 including means provided towards the outlet of the die for maintaining back pressure within the die passage.
Claim 16
Dependent Claim
35 words
An extruder as claimed in anyone of claims 11 to 13 wherein the relaxation zone is defined by a breaker plate assembly debouching into an upper end of the die passage constituting a relaxation zone.
Claim 17
Dependent Claim
63 words
An extruder as claimed in anyone of claims 11 to 14 wherein the heating in the die means is effected by the application of external heat and by the working of the material passing one or more constrictions to provide substantially uniform heating of the material to a temperature at or greater than that at which crosslinking occurs thereby initiating the crosslinking reaction.
Claim 18
Dependent Claim
72 words
An extruder as claimed in anyone of claims 1 to 15 wherein the relaxation zone comprises a conduit means for the admission of a crosslinkable material thereto from said high pressure means, said conduit having a constriction within a passage to cause or allow working of the material as it passes therethrough and heating means for heating the contents of said passage towards the threshold temperature at which cross- linking takes place.
Claim 19
Dependent Claim
83 words
17 An extruder as claimed in anyone of claims 1 to 16 wherein the die means comprises a longitudinal passage defining the shape to be imparted to the material, heating means to heat said passage and said material and constriction means to effect working of the material towards an inlet end thereof to raise the temperature of the material above the threshold temperature at which crosslinking takes place thereby allowing crosslinking to proceed to completion as the material passes along said die passage.
Claim 20
Dependent Claim
41 words
An extruder as claimed in claim 13 wherein the means for maintaining back pressure within the die passage is a constrictor member arranged at the exit end of said die passage to restrict the exit therefrom of the substantially crosslinked material.
Claim 21
Dependent Claim
30 words
An extruder as claimed in claim 14 when the breaker plate assembly defining a plurality of feed orifices upstream of the relaxation zone and communicating with the high pressure means.
Claim 22
Dependent Claim
36 words
An extruder as claimed in claim 19 wherein the breaker plate assembly comprises a plate having a plurality of circumferentially spaced orifices through which the material passes from the high pressure means to the relaxation zone.
Claim 23
Dependent Claim
45 words
21 An extruder as claimed in anyone of claims 11 to 20 wherein the high pressure means comprises a zone in which instantaneous compressions are applied to a mixture of material for generating pressure within the material thereby producing a substantially uniform temperature rise therewithin.
Claim 24
Dependent Claim
16 words
An extruder as claimed in claim 21 wherein the pressure generated is at least 1000 atmospheres.
References Cited (Backward Citations)
US3876736A
Cited
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