EP0532154A2
Expired / Lapsed
EP
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Process for devolatilization of polylactides
Assignee: Camelot Superabsorbents Ltd
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Filing: 1992-06-03
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Granted: —
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Expires: 2012-06-03
Abstract
Abstract Biodegradable aliphatic polyesters may be devolatilized by passing them through a shear zone and concurrently applying a vacuum to them.
Inventors
- 👤 James Lunt
- 👤 James M. Makuc
- 👤 Michael Castriotta
- 👤 Israel David Fridman
- 👤 James T. Mcqueen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 23:25
CPC Classifications
B; B29; B29C; B29C67/00; B29C67/24; C; C08; C08G; C08G63/00; C08G63/88; C08G63/90
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
113 words
A process to reduce the residual monomer content to less than 5 weight % in a polymer comprising one or more monomers of the Formula: -OCR₁R₂(CR₃R₄) n CO- I wherein in Formula I, R₁, R₂, R₃ and R₄ are independently selected from a hydrogen atom and a C₁₋₄ alkyl radical, and n is 0 or an integer from 1 to 5, characterised by passing the polymer through a shear zone, said shear zone having at least one vacuum port, said polymer being at a temperature from the melting temperature of the polymer up to 250°C, and applying a vacuum of not greater than 750 mm of Hg to at least one vacuum port.
Claim 2
Dependent Claim
19 words
A proccss according to claim 1, characterised by said shear zone comprises an injection molding machine or an extruder.
Claim 3
Dependent Claim
15 words
The process according to claim 2, characterised by said extruder is a twin screw extruder.
Claim 4
Dependent Claim
17 words
The process according to claim 3, characterised by said twin screw extruder is operated in counter-rotating mode.
Claim 5
Dependent Claim
16 words
The process according to claim 4, characterised by said extruder has at least two vacuum ports.
Claim 6
Dependent Claim
23 words
The process according to claim 5, characterised by said vacuum ports are operated at vacuums of not more than 735 mm of Hg.
Claim 7
Dependent Claim
40 words
The process according to claim 6, characterised by the lines from said vacuum port to the source of vacuum are heated at a temperature above the highest melting temperature of residual monomer and have traps prior to the vacuum source.
Claim 8
Dependent Claim
23 words
The process according to claim 6, characterised by the screws in said extruder are operated at a rate from 4 to 300 RPM's.
Claim 9
Dependent Claim
23 words
The process according to claim 6, characterised by the screws in said extruder are operated at a rate from 50 to 200 RPM's.
Claim 10
Dependent Claim
24 words
The process according to claim 9, characterised by the zones in the barrel of said extruder are heated to temperatures from 150 to 220°C.
Claim 11
Dependent Claim
22 words
The process according to claim 10, characterised by said extruder is a twin screw extruder and is operated in a counter-rotating mode.
Claim 12
Dependent Claim
22 words
The process according to claim 10, characterised by said extruder is a twin screw extruder and is operated in a co-rotating mode.
Claim 13
Dependent Claim
19 words
The process according to claim 11, characterised by the residual monomer is reduced to less than 2 weight %.
Claim 14
Dependent Claim
19 words
The process according to claim 12, characterised by the residual monomer is reduced to less than 2 weight %.
Claim 15
Dependent Claim
39 words
The process according to claim 13, characterised by further comprising adding to said monomer from 0.1 to 5 weight % of one or more of antioxidants and heat and light stabilizers prior to passing said polymer through said extruder.
Claim 16
Dependent Claim
39 words
The process according to claim 14, characterised by further comprising adding to said monomer from 0.1 to 5 weight % of one or more of antioxidants and heat and light stabilizers prior to passing said polymer through said extruder.
Claim 17
Dependent Claim
35 words
The process according to claim 15, characterised by said polymer is a homopolymer of Formula I, wherein n is 0 and one of R₁, and R₂ is a methyl radical and the other is hydrogen.
Claim 18
Dependent Claim
35 words
The process according to claim 16, characterised by said polymer is a homopolymer of Formula I, wherein n is 0 and one of R₁, and R₂ is a methyl radical and the other is hydrogen.
Claim 19
Dependent Claim
23 words
The process according to Claim 1, characterised by further comprising a injecting a monomer entraining gas into the polymer melt in the extruder.
Claim 20
Dependent Claim
23 words
The process according to Claim 7, characterised by further comprising a injecting a monomer entraining gas into the polymer melt in the extruder.
Claim 21
Dependent Claim
23 words
The process according to Claim 13, characterised by further comprising a injecting a monomer entraining gas into the polymer melt in the extruder.
Claim 22
Dependent Claim
23 words
The process according to Claim 14, characterised by further comprising a injecting a monomer entraining gas into the polymer melt in the extruder.
Claim 23
Dependent Claim
18 words
A polymer, characterised by being provided by a process according to any one of claims 1 to 22.
References Cited (Backward Citations)
No citation records indexed.
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