US4115369A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for continuous production of oxymethylene polymers
Assignee: Mitsubishi Gas Chemical Co Inc
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Filing: 1977-11-29
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Granted: 1978-09-19
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Expires: 1997-11-29
Abstract
Abstract A process for continuously producing an oxymethylene polymer by continuously polymerizing a starting monomer containing at least 50 mole% of trioxane in bulk in the presence of a catalyst, which comprises feeding the starting monomer into a first-stage polymerization reactor having a self-cleaning action to perform a first-stage polymerization reaction until the conversion reaches 40 to 70%, withdrawing the reaction mixture as a powder from the outlet of the first-stage polymerization reactor, feeding the reaction mixture into a second-stage polymerization reactor having a stirring action to perform a second-stage polymerization reaction until the conversion reaches 95 to 100%, and then withdrawing the polymerization product as a powder from the outlet of the second-stage polymerization reactor.
Inventors
- 👤 Akitoshi Sugio
- 👤 Tomotaka Furusawa
- 👤 Katsumasa Tanaka
- 👤 Toshikazu Umemura
- 👤 Hiroyuki Urabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:21
CPC Classifications
C; C08; C08G; C08G2/00; C08G2/18; B; B01; B01J; B01J19/00; B01J19/18; B01J19/20; C08G2/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
115 words
A process for continuously producing an oxymethylene polymer by continuously polymerizing a starting monomer containing at least 50 mole% of trioxane in bulk in the presence of a catalyst, which comprises feeding the starting monomer into a first-stage polymerization reactor having a self-cleaning action to perform a first-stage polymerization reaction until the conversion reaches 40 to 70%, withdrawing the reaction mixture as a powder from the outlet of the first-stage polymerization reactor, feeding the reaction mixture into a second-stage polymerization reactor having a stirring action to perform a second-stage polymerization reaction until the conversion reaches 95 to 100%, and then withdrawing the polymerization product as a powder from the outlet of the second-stage polymerization reactor.
Claim 2
Dependent Claim
115 words
A process for continuously producing an oxymethylene polymer by continuously polymerizing a starting monomer containing at least 50 mole% of trioxane in bulk in the presence of a catalyst, which comprises feeding the starting monomer into a first-stage polymerization reactor having a self-cleaning action to perform a first-stage polymerization reaction until the conversion reaches 40 to 70%, withdrawing the reaction mixture as a powder from the outlet of the first-stage polymerization reactor, feeding the reaction mixture into a second-stage polymerization reactor having a stirring action to perform a second-stage polymerization reaction until the conversion reaches 95 to 100%, and then withdrawing the polymerization product as a powder from the outlet of the second-stage polymerization reactor.
Claim 3
Dependent Claim
127 words
The process of claim 1 wherein the first-stage polymerization reactor is a reactor comprising a barrel having an external heating or cooling jacket and at least two horizontal stirring shafts inside, in which each of the horizontal stirring shafts has a plurality of paddles fixed thereto, the paddles have such a shape that when the horizontal stirring shafts are rotated simultaneously in the same direction, the pointed ends of the paddles fixed to one of the horizontal stirring shafts always keep a slight clearance from the inside surface of the barrel or the paddles fixed to the other horizontal stirring shaft, and in which the reaction mixture in the barrel is moved from the inlet to the outlet of the reactor by the rotation of the paddles.
Claim 4
Dependent Claim
67 words
The process of claim 1 wherein the second-stage polymerization reactor is a reactor having a high heat transmission surface comprising an external heating or cooling jacket and one or a plurality of horizontal stirring shafts inside in which a plurality of stirring vanes are fixed to each horizontal stirring shaft and the reaction mixture within the barrel is slowly stirred by the rotation of the stirring vanes.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein the reaction temperature in the first-stage reactor is 0° to 150° C.
Claim 6
Dependent Claim
22 words
The process of claim 1 wherein the residence time of the reaction mixture in the first-stage reactor is 0.5 to 30 minutes.
Claim 7
Dependent Claim
18 words
The process of claim 1 wherein the reaction temperature in the second-stage reactor is 0° to 130° C.
Claim 8
Dependent Claim
22 words
The process of claim 1 wherein the residence time of the reaction mixture in the second-stage reactor is 5 to 60 minutes.
References Cited (Backward Citations)
US3254053A
Cited
US3442866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-18 | 1982-03-20 | 1982-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-18 | 1986-03-20 | 1986-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-18 | 1990-03-20 | 1990-09-19 | $7700.00 | Window Closed / Lapsed |