Patent AT229902B successfully refreshed from Google Patents.
Patent EP0149335A2 successfully refreshed from Google Patents.
EP0149335A2
Expired / Lapsed
EP
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Apparatus and method for extruding polymer melts
Assignee: BP Chemicals Ltd
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Filing: 1984-12-13
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Granted: —
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Expires: 2004-12-13
Abstract
Abstract This invention relates to an apparatus and a method for extruding polymer melts, especially to produce blown films of reduced surface damage caused by melt-fracture. The apparatus is an extrusion die which has a means for heating the die lips provided on or embedded into the face thereof. The extrusion die of this invention may be used for extrusion of melts of polyolefins, polyesters, polystyrene, polyamides, polyvinyl chloride and polyvinylidene chloride.
Inventors
- 👤 John Alexander Bp Chemicals Limited Torkington
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 13:51
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/78; B29C48/86; B29C48/03; B29C48/09; B29C48/10; B29C48/30; B29C48/32; B29C48/865; B29C48/06; B29C48/07; B29C48/08; B29K; B29K2995/00; B29K2995/0037; B29K2995/0072; B29K2995/0073
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
44 words
An extrusion die for producing extrudates from polymer melts, said extrusion die comprising a die body and die lips through which the extrudate exits, characterised in that means for heating the die lips is provided on or embedded into the fact of the die.
Claim 2
Dependent Claim
44 words
An extrusion die for producing extrudates from polymer melts, said extrusion die comprising a die body and die lips through which the extrudate exits, characterised in that means for heating the die lips is provided on or embedded into the fact of the die.
Claim 3
Dependent Claim
35 words
An extrusion die according to claim 1 wherein the means for heating the die lips is capable of heating a zone of the die lips, the heated lip zone being insulated from the die body.
Claim 4
Dependent Claim
31 words
An extrusion die according to claim 2 wherein the heated die lip zone extends from the die lip exit to a depth not greater than about 1 cm into the die.
Claim 5
Dependent Claim
32 words
An extrusion die according to claim 2 or 3 wherein the heated die lip zone extends from the die lip exit to a depth not greater than 0.5 cm into the die.
Claim 6
Dependent Claim
24 words
An extrusion die according to any one of the preceding claims wherein the means for heating the die lips is a peripheral ring heater.
Claim 7
Dependent Claim
59 words
An extrusion die according to any one of the preceding claims 1 to 4 wherein the die is an annular die for manufacturing pipe or blown film comprising a mandrel having a face and a core and the heating means is provided on or embedded into the face of the mandrel or provided in the core of the mandrel.
Claim 8
Dependent Claim
67 words
An extrusion die according to any one of the preceding claims wherein the die lips and die body are integrally formed, characterised in that the area of metal/metal contact between the heated die lips and die body is less than 50X of the cross sectional area of the die body at its maximum cross section in a plane perpendicular to the flow path of the polymer melt.
Claim 9
Dependent Claim
51 words
A process for extruding thermoplastic polymer using an extrusion die comprising die body and die lips spaced by a die land characterised in that the temperature of the die lips is maintained at least 10°C above the temperature of the die land at a depth of 1.5 cm into the die.
Claim 10
Dependent Claim
51 words
A process for extruding thermoplastic polymer using an extrusion die comprising die body and die lips spaced by a die land characterised in that the temperature of the die lips is maintained at least 10°C above the temperature of the die land at a depth of 1.5 cm into the die.
Claim 11
Dependent Claim
22 words
A process according to claim 8 wherein the thermoplastic polymer is selected from polyolefins, polyesters, polystyrene, polyamides, polyvinyl chloride and polyvinylidene chloride.
Claim 12
Dependent Claim
19 words
A process according to claim 8 or 9 whenever used to produce blown films from linear low density polyethylene.
References Cited (Backward Citations)
No citation records indexed.
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