US5656719A
Expired / Lapsed
US
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Condensation injection molding process for producing bottle preforms of polyethylene terephthalate and/or its copolyesters and resultant preforms
Assignee: Uhde Inventa Fischer AG
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Filing: 1996-02-14
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Granted: 1997-08-12
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Expires: 2016-02-14
Abstract
Abstract A process for producing bottle preforms from the melt of polyethylene terephthalate and/or its copolyesters, includes selectively introducing an inert gas into the continuous flow or partial flow of the polyester melt from a poly-condensation having an intrinsic viscosity between 0.5 and 0.75 dl/g, subsequently bringing the melt to an acetaldehyde content below 10 ppm in a melt after-condensation reactor and to an intrinsic viscosity of 0.75 to 0.95 dl/g and thereafter guiding the melt into an injection molding tool and processing same.
Inventors
- 👤 Werner Stibal
- 👤 Werner Kaegi
- 👤 Joachim Ensinger
- 👤 Klaus Nothhelfer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:44
CPC Classifications
B; B29; B29B; B29B11/00; B29B11/06; B29B11/08; B29C; B29C45/00; B29C45/0001; C; C08; C08G; C08G63/00; C08G63/88; B29K; B29K2067/00; B29K2067/003; B29K2105/00; B29K2105/0002; B29K2105/25; B29K2105/253; B29K2667/00; B29K2667/003; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/54
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
106 words
A condensation injection molding process for producing bottle preforms from the melt of polyethylene terephthalate or a copolyester thereof, wherein an inert gas is optionally introduced into a flow of the polyester melt from a poly-condensation, having an intrinsic viscosity between 0.5 and 0.75 dl/g, subsequently the melt is brought to an acetaldehyde content below 10 ppm, under vacuum at a temperature range between 285° to 260° C. in a melt post-condensation reactor and to an intrinsic viscosity of 0.75 to 0.95 dl/g, during a residence time of less than 60 min., and is immediately thereafter guided into an injection molding tool and processed into preforms.
Claim 2
Dependent Claim
106 words
A condensation injection molding process for producing bottle preforms from the melt of polyethylene terephthalate or a copolyester thereof, wherein an inert gas is optionally introduced into a flow of the polyester melt from a poly-condensation, having an intrinsic viscosity between 0.5 and 0.75 dl/g, subsequently the melt is brought to an acetaldehyde content below 10 ppm, under vacuum at a temperature range between 285° to 260° C. in a melt post-condensation reactor and to an intrinsic viscosity of 0.75 to 0.95 dl/g, during a residence time of less than 60 min., and is immediately thereafter guided into an injection molding tool and processed into preforms.
Claim 3
Dependent Claim
16 words
A process in accordance with claim 1, wherein said copolyester contains maximally 10 mol-% of co-monomers.
Claim 4
Dependent Claim
30 words
A process in accordance with claim 2, wherein said co-monomers are selected from the group of consisting of lactones, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 1,4cyclohexane dimethanol, diethylene glycol and mixtures thereof.
Claim 5
Dependent Claim
14 words
A process in accordance with claim 1, wherein temperature decreases during said residence time.
Claim 6
Dependent Claim
19 words
A process in accordance with claim 1, wherein the residence time in the reactor is less than 40 minutes.
Claim 7
Dependent Claim
19 words
A process in accordance with claim 1, wherein the melt is brought to an acetaldehyde content below 5 ppm.
Claim 8
Dependent Claim
23 words
A process in accordance with claim 1, wherein a screw reactor with at least two screw-shafts is used as the melt post-condensation reactor.
Claim 9
Dependent Claim
23 words
A process according to claim 1, comprising conveying the melt from the post-condensation reactor to the injection molding tool with a conveying device.
Claim 10
Dependent Claim
20 words
A process in accordance with claim 8, wherein a device with a double-piston system is employed as the conveying device.
Claim 11
Dependent Claim
15 words
A process in accordance with claim 1, wherein the vacuum is maintained below 1 mbar.
Claim 12
Dependent Claim
22 words
A process in accordance with claim 1, wherein carbon dioxide in a supercritical state or nitrogen is introduced as the inert gas.
Claim 13
Dependent Claim
14 words
A process according to claim 1, wherein said copolyester contains 2-5 mol-% of co-monomers.
Claim 14
Dependent Claim
30 words
A process in accordance with claim 12, wherein said co-monomers are selected from the group of consisting of lactones, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 1,4-cyclohexane dimethanol, diethylene glycol and mixtures thereof.
Claim 15
Dependent Claim
14 words
A process in accordance with claim 13, wherein temperature decreases during said residence time.
Claim 16
Dependent Claim
19 words
A process in accordance with claim 14, wherein the residence time in the reactor is less than 40 minutes.
Claim 17
Dependent Claim
23 words
A process in accordance with claim 15, wherein a screw reactor with at least two screw-shafts is used as the melt post-condensation reactor.
Claim 18
Dependent Claim
23 words
A process according to claim 15, comprising conveying the melt from the post-condensation reactor to the injection molding tool with a conveying device.
Claim 19
Dependent Claim
20 words
A process in accordance with claim 17, wherein a device with a double-piston system is employed as the conveying device.
Claim 20
Dependent Claim
15 words
A process in accordance with claim 18, wherein the vacuum is maintained below 1 mbar.
Claim 21
Dependent Claim
22 words
A process in accordance with claim 19, wherein carbon dioxide in a supercritical state or nitrogen is introduced as the inert gas.
Claim 22
Dependent Claim
19 words
A preform produced in accordance with claim 1, wherein the acetaldehyde content of the preforms is maximally 10 ppm.
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