CA2130029A1 - Device for the continuous preparation of polyacetals and its use - Google Patents
Device for the continuous preparation of polyacetals and its useInfo
- Publication number
- CA2130029A1 CA2130029A1 CA002130029A CA2130029A CA2130029A1 CA 2130029 A1 CA2130029 A1 CA 2130029A1 CA 002130029 A CA002130029 A CA 002130029A CA 2130029 A CA2130029 A CA 2130029A CA 2130029 A1 CA2130029 A1 CA 2130029A1
- Authority
- CA
- Canada
- Prior art keywords
- zone
- static mixing
- polymerization
- polyacetals
- elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/24—Stationary reactors without moving elements inside
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
- C08G2/10—Polymerisation of cyclic oligomers of formaldehyde
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
- C08G2/30—Chemical modification by after-treatment
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- General Chemical & Material Sciences (AREA)
- Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)
- Polymerisation Methods In General (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
Abstract Device for continuous preparation of polyacetals and its use The invention thus relates to a device for the continuous preparation of polyacetals in a homogeneous phase in the form of a flow tube equipped with static mixing elements, in which the static mixing elements as are arranged in series, b) vary in length and diameter according to the individual process step and c) are not separated by built-in backing-up elements or bottlenecks.
Description
`` 2~Q~ 3 HOECHST ARTIENGESELLSCXAFT HOE 93/F 238 Dr. R/bs Device for the continuous preparation of polyacetal~ and its u~e Description The invention relates to a device for the continuous preparation and substantial end group ~tabilization of polyacetals in a homogeneous phase and to its use.
Numerous processe~ for the preparation of oxymethylene-homo- and oxymethylcopolymers from formaldehyde or cyclic oligomers of formaldehyde, in particular trioxane, in the presence of initiator~ which have a cationic action are known. Continuous polymerization o the monomers on an industrial scale is de~cribed, for example, in the Patent~ US 3 027 352, US 3 803 094, DE 1 161 421, 15 DE 495 228, DE 1 720 358 and DE 30 18 898. Polymerization reactors which are described are, inter alia, kneaders, extruders, mills and belts. A common feature of the~e proces~es is a phase transition from gaseous or liguid monomers to the partly crystalline solid polymer which takes place during the polymerization. Thi~ leads to problem~ in removal of the heat of polymerization and crystallization liberated, and a~ a conseguence cause~
losses in conversion.
The Patent EP-B 0 080 656 descr~bes a process for the continuous bulk polymerization of trioxane in a homo-geneous liquid phase at temperature~ above 135C. This proces~ procedure avoids a phase transition during the polymerization. In addition to the abovementioned apparatus, flow tube~ with and without static mixers are mentioned as polymerization reactors. It iB furthermore ~tated of the deactivation reactor that it is separated ~patially from the polymerizat~on reactor in ~uch a way that penetration of the deactivator into the polymerization reactor is reliably excluded. This is ' . . .
Numerous processe~ for the preparation of oxymethylene-homo- and oxymethylcopolymers from formaldehyde or cyclic oligomers of formaldehyde, in particular trioxane, in the presence of initiator~ which have a cationic action are known. Continuous polymerization o the monomers on an industrial scale is de~cribed, for example, in the Patent~ US 3 027 352, US 3 803 094, DE 1 161 421, 15 DE 495 228, DE 1 720 358 and DE 30 18 898. Polymerization reactors which are described are, inter alia, kneaders, extruders, mills and belts. A common feature of the~e proces~es is a phase transition from gaseous or liguid monomers to the partly crystalline solid polymer which takes place during the polymerization. Thi~ leads to problem~ in removal of the heat of polymerization and crystallization liberated, and a~ a conseguence cause~
losses in conversion.
The Patent EP-B 0 080 656 descr~bes a process for the continuous bulk polymerization of trioxane in a homo-geneous liquid phase at temperature~ above 135C. This proces~ procedure avoids a phase transition during the polymerization. In addition to the abovementioned apparatus, flow tube~ with and without static mixers are mentioned as polymerization reactors. It iB furthermore ~tated of the deactivation reactor that it is separated ~patially from the polymerizat~on reactor in ~uch a way that penetration of the deactivator into the polymerization reactor is reliably excluded. This is ' . . .
- 2 - 2~ 2~
achieved by built-in elements such as bottlenecks and/or backing-up elements. It must be concluded from this that the deactivator is metered in only after the separation devices.
The object of the present invention wa~ to design a reactor in which the preparation of polyacetal homo- and copolymers aan be carried out in a simplified manner. It has been achieved by a certain type of reactor in which the individual process zones, i.e. mixing of the monomers and the initiator, the polymerization reaction, the deactivation and the substantial hydrolytic degradation of the unstable chain ends or end group closure, are continuous.
The invention thu~ relates to a device for the continuous preparation o$ polyacetals in a homogeneous pha~e in the form of a flow tube equipped with static mixing elements, in which the static mixing elements a) are arranged in series, b) vary in length and diameter according to the individual process step and c) are not separated by built-in backing-up elements or bottlenecks.
The reactor according to the invention is preferably built up from individual section~, 80 that a high flexibility of the reactor assembly is achieved. Another advantage is that the reactor comprises no mechanically moved parts and is thus not particularly susceptible to malfunction. The reactor which has been assembled in courses is fitted with static mixing elements ovor its entire length. Static mixers which can be employed are, for example, SMX or SMR mixers from SULZER (Winterthur, Switzerland), Kenic~ mixers (Chemineer Clevepad Ltd., West Meadows, England) or other static mixing element~.
The internal diameter and the length of the individual reactor section depend on the deslred throughput, on tho process step to be carried out there and on the viscosi~y of the product produced in the section. By this arrangement of the reactor, a narro~ residence time ~ . . , , , - . ~ . , .
_ 3 _ 2~3~2~
spectrum of the reaction material iB rendered possible, which i8 necessary and es~ential for a high product quality.
The reactor according to the invention i~ built up from four zones: the mixing zone, in which two low-vi~cosity constituents, the monomer~ and the initiator, are mixed, the polymerization zone, in which the polymerizat~on takes place, the deactivator admixing zone, in which the low-viscosity deactivator is added to the high-vi~cosity polymer melt, and the deactivation and stabilization zone, in which the deactivation and stabilization are carried out and brought to completion. The stabilization is rendered possible by hydrolytic degradation of the unstable chain ends in the case of polyacetal copolymers or end group closure in the case of polyacetal homo-polymers. The individual process zones are continuous.
The end or the polymerization zone ie determined by the site of addition of the d-activator. Preferably, rapid admixing of the deactivator is rendered possible if the shear is increased briefly in this zone. This can be achieved by a reduction in the reactor diameter, tho metering-in taking place at the start of the narrowing, or by static mixing elements of another design.
In order to establish the residence times to be main-tained in the individual process zones, it is necessary for the length and diameter of the individual mixing elements to be ad~usted to suit the process ~teps ln que~tion.
In the initiation zone, the static mixing elements and the reactor diameter are to have dimensions such that a maximum residence time of 0.1 to 10 seconds, preferably 0.5 to 5, and in particular 0.5 to 2 seconds, i~ main-tained without polymerization taking place. The time should be sufficient by itself to ensure thorough mixing of the starting materials.
, . . . . . .. .. .... . .. . . .. . .
--~ 2!3~ 32~
In the polymerization zone, the static mixing elemente and the reactor diameter are to be designed 3uch that the polymerization re~idence time is 0.1 to 10 minutes, preferably 0.3 to 5 minutes and in particular 0.5 to 2 mlnutes. Under these conditionE, conversion~ of 60 to 80%
can be achieved.
The re~idence time in the sub~equent deactivation and ~tabilization zone i8 0.2 to 15 minutee, preferably 1 to 10 minutes and in particular 2 to 5 minutes.
Stabilization is to be understood as meaning hydrolytic degradation of the un~table chain end~ in the case of ~he polyacetal copolymers and end group closure in the case of polyacetal homopolymer~. -The pres~ure in the reactor, in general 2 15 bar, is establi~hed by a throttle valve on the reactor outlet, via which the product ic 2180 let down to atmo~pheric pressure, whereupon it solidifies ~pontaneously.
The polymer leaving the reactor must be freed from residual monomers, degradation products, ~uch as formal-dehyde, and amine and water. As is known, th~s iBeffected, for example, in a flash cha~ber and with subsequent degassing extru~ion. If appropriate, a further stabilizing step can be carried out in the degascing extruder in the case of polyacetal copolymers.
Fl~ure 1 ~hows a diagram of the reactor according to the invention.
-; :
. . ~ . ~ .
achieved by built-in elements such as bottlenecks and/or backing-up elements. It must be concluded from this that the deactivator is metered in only after the separation devices.
The object of the present invention wa~ to design a reactor in which the preparation of polyacetal homo- and copolymers aan be carried out in a simplified manner. It has been achieved by a certain type of reactor in which the individual process zones, i.e. mixing of the monomers and the initiator, the polymerization reaction, the deactivation and the substantial hydrolytic degradation of the unstable chain ends or end group closure, are continuous.
The invention thu~ relates to a device for the continuous preparation o$ polyacetals in a homogeneous pha~e in the form of a flow tube equipped with static mixing elements, in which the static mixing elements a) are arranged in series, b) vary in length and diameter according to the individual process step and c) are not separated by built-in backing-up elements or bottlenecks.
The reactor according to the invention is preferably built up from individual section~, 80 that a high flexibility of the reactor assembly is achieved. Another advantage is that the reactor comprises no mechanically moved parts and is thus not particularly susceptible to malfunction. The reactor which has been assembled in courses is fitted with static mixing elements ovor its entire length. Static mixers which can be employed are, for example, SMX or SMR mixers from SULZER (Winterthur, Switzerland), Kenic~ mixers (Chemineer Clevepad Ltd., West Meadows, England) or other static mixing element~.
The internal diameter and the length of the individual reactor section depend on the deslred throughput, on tho process step to be carried out there and on the viscosi~y of the product produced in the section. By this arrangement of the reactor, a narro~ residence time ~ . . , , , - . ~ . , .
_ 3 _ 2~3~2~
spectrum of the reaction material iB rendered possible, which i8 necessary and es~ential for a high product quality.
The reactor according to the invention i~ built up from four zones: the mixing zone, in which two low-vi~cosity constituents, the monomer~ and the initiator, are mixed, the polymerization zone, in which the polymerizat~on takes place, the deactivator admixing zone, in which the low-viscosity deactivator is added to the high-vi~cosity polymer melt, and the deactivation and stabilization zone, in which the deactivation and stabilization are carried out and brought to completion. The stabilization is rendered possible by hydrolytic degradation of the unstable chain ends in the case of polyacetal copolymers or end group closure in the case of polyacetal homo-polymers. The individual process zones are continuous.
The end or the polymerization zone ie determined by the site of addition of the d-activator. Preferably, rapid admixing of the deactivator is rendered possible if the shear is increased briefly in this zone. This can be achieved by a reduction in the reactor diameter, tho metering-in taking place at the start of the narrowing, or by static mixing elements of another design.
In order to establish the residence times to be main-tained in the individual process zones, it is necessary for the length and diameter of the individual mixing elements to be ad~usted to suit the process ~teps ln que~tion.
In the initiation zone, the static mixing elements and the reactor diameter are to have dimensions such that a maximum residence time of 0.1 to 10 seconds, preferably 0.5 to 5, and in particular 0.5 to 2 seconds, i~ main-tained without polymerization taking place. The time should be sufficient by itself to ensure thorough mixing of the starting materials.
, . . . . . .. .. .... . .. . . .. . .
--~ 2!3~ 32~
In the polymerization zone, the static mixing elemente and the reactor diameter are to be designed 3uch that the polymerization re~idence time is 0.1 to 10 minutes, preferably 0.3 to 5 minutes and in particular 0.5 to 2 mlnutes. Under these conditionE, conversion~ of 60 to 80%
can be achieved.
The re~idence time in the sub~equent deactivation and ~tabilization zone i8 0.2 to 15 minutee, preferably 1 to 10 minutes and in particular 2 to 5 minutes.
Stabilization is to be understood as meaning hydrolytic degradation of the un~table chain end~ in the case of ~he polyacetal copolymers and end group closure in the case of polyacetal homopolymer~. -The pres~ure in the reactor, in general 2 15 bar, is establi~hed by a throttle valve on the reactor outlet, via which the product ic 2180 let down to atmo~pheric pressure, whereupon it solidifies ~pontaneously.
The polymer leaving the reactor must be freed from residual monomers, degradation products, ~uch as formal-dehyde, and amine and water. As is known, th~s iBeffected, for example, in a flash cha~ber and with subsequent degassing extru~ion. If appropriate, a further stabilizing step can be carried out in the degascing extruder in the case of polyacetal copolymers.
Fl~ure 1 ~hows a diagram of the reactor according to the invention.
-; :
. . ~ . ~ .
Claims (7)
1. A device in the form of a flow tube equipped with static mixing elements for the preparation of poly-acetal, wherein the static mixing elements a) are arranged in series, b) vary in length and diameter according to the individual process step and c) are not separated by built-in backing-up elements or bottlenecks.
2. A device as claimed in claim 1, wherein the device has a mixing zone, a polymerization zone, a de-activator admixing zone and a deactivation or stabi-lization zone.
3. A device as claimed in claim 1 or 2, wherein the static mixing element and the diameter in the initiation zone have dimensions such that a resi-dence time of 0.1 to 10 seconds is maintained.
4. A device as claimed in claim 1 or 2, wherein the static mixing element and the diameter in the polymerization zone have dimensions such that the polymerization time is 0.1 to 10 minutes.
5. A device as claimed in claim 1 or 2, wherein the residence time in the deactivation and stabilization zone is 0.2 to 15 minutes.
6. A device as claimed in one or more of claims 1 to 5, wherein a degassing unit is connected to the device.
7. The use of a device as claimed in one or more of claims 1 to 6 for the continuous preparation of polyacetals in a homogeneous phase.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4327246.0 | 1993-08-13 | ||
| DE4327246A DE4327246A1 (en) | 1993-08-13 | 1993-08-13 | Device for the continuous production of polyacetals and their use |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2130029A1 true CA2130029A1 (en) | 1995-02-14 |
Family
ID=6495133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002130029A Abandoned CA2130029A1 (en) | 1993-08-13 | 1994-08-12 | Device for the continuous preparation of polyacetals and its use |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0638357B1 (en) |
| JP (1) | JP3285278B2 (en) |
| KR (1) | KR100332842B1 (en) |
| CN (1) | CN1042341C (en) |
| BR (1) | BR9403238A (en) |
| CA (1) | CA2130029A1 (en) |
| DE (2) | DE4327246A1 (en) |
| RU (1) | RU2130949C1 (en) |
| TW (1) | TW362990B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7863393B2 (en) | 2004-11-30 | 2011-01-04 | Basf Ag | Method for producing polyoxymethylenes |
| WO2014102695A2 (en) | 2012-12-31 | 2014-07-03 | Ticona Gmbh | Process for producing polyoxymethylene polymers with long-chain alkyl end groups, and polymers made therefrom |
| WO2014102696A2 (en) | 2012-12-31 | 2014-07-03 | Ticona Gmbh | Polyoxymethylene polymer with long chain alkylene glycol end groups |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4431575A1 (en) | 1994-09-05 | 1996-03-07 | Hoechst Ag | Process for the preparation of polyacetal copolymers |
| DE4443150C2 (en) * | 1994-12-05 | 2000-02-24 | Hoechst Ag | Acetal copolymers with improved mechanical properties |
| US7109378B2 (en) | 2001-08-30 | 2006-09-19 | Air Products And Chemicals, Inc. | Monolith catalytic reactor coupled to static mixer |
| DE102005022641A1 (en) * | 2005-05-11 | 2006-11-16 | Basf Ag | Improved process for residual monomer removal from polyoxyethylene |
| EP2267075B1 (en) | 2008-10-28 | 2014-01-22 | Asahi Kasei Chemicals Corporation | Polyacetal resin composition and method for producing the same |
| CN102844374B (en) | 2010-04-16 | 2014-04-02 | 旭化成化学株式会社 | Polyacetal resin composition, process for production of the composition, and molded article |
| BR112015029564A2 (en) * | 2013-05-29 | 2017-07-25 | Basf Se | continuous process for the preparation of polyoxazolines, polyoxazoline, and tubular reactor segment |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3803094A (en) * | 1972-07-12 | 1974-04-09 | Ube Industries | Process for producing formaldehyde copolymer |
| JPS55164212A (en) * | 1979-05-18 | 1980-12-20 | Mitsubishi Gas Chem Co Inc | Continuous polymerization of oxymethylene (co) polymer |
| DE3066423D1 (en) * | 1979-11-06 | 1984-03-08 | Ube Industries | Process for polymerizing formaldehyde |
| DE3147309A1 (en) * | 1981-11-28 | 1983-06-01 | Basf Ag, 6700 Ludwigshafen | CONTINUOUS PROCESS FOR PRODUCING OXYMETHYLENE POLYMERS |
| US4975520A (en) * | 1989-03-20 | 1990-12-04 | Hoechst Celanese Corp. | Production of acetal copolymers from gaseous formaldehyde and cyclic ethers |
-
1993
- 1993-08-13 DE DE4327246A patent/DE4327246A1/en not_active Withdrawn
-
1994
- 1994-07-28 EP EP94111763A patent/EP0638357B1/en not_active Expired - Lifetime
- 1994-07-28 DE DE59408857T patent/DE59408857D1/en not_active Expired - Fee Related
- 1994-08-12 RU RU94029665A patent/RU2130949C1/en active
- 1994-08-12 KR KR1019940019870A patent/KR100332842B1/en not_active IP Right Cessation
- 1994-08-12 BR BR9403238A patent/BR9403238A/en not_active IP Right Cessation
- 1994-08-12 CN CN94109420A patent/CN1042341C/en not_active Expired - Fee Related
- 1994-08-12 CA CA002130029A patent/CA2130029A1/en not_active Abandoned
- 1994-08-15 JP JP19152794A patent/JP3285278B2/en not_active Expired - Fee Related
- 1994-08-31 TW TW83108020A patent/TW362990B/zh not_active IP Right Cessation
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7863393B2 (en) | 2004-11-30 | 2011-01-04 | Basf Ag | Method for producing polyoxymethylenes |
| WO2014102695A2 (en) | 2012-12-31 | 2014-07-03 | Ticona Gmbh | Process for producing polyoxymethylene polymers with long-chain alkyl end groups, and polymers made therefrom |
| WO2014102696A2 (en) | 2012-12-31 | 2014-07-03 | Ticona Gmbh | Polyoxymethylene polymer with long chain alkylene glycol end groups |
Also Published As
| Publication number | Publication date |
|---|---|
| DE59408857D1 (en) | 1999-12-02 |
| EP0638357A3 (en) | 1995-10-18 |
| BR9403238A (en) | 1995-04-11 |
| JPH0770267A (en) | 1995-03-14 |
| DE4327246A1 (en) | 1995-02-16 |
| RU2130949C1 (en) | 1999-05-27 |
| TW362990B (en) | 1999-07-01 |
| EP0638357B1 (en) | 1999-10-27 |
| RU94029665A (en) | 1996-06-10 |
| CN1042341C (en) | 1999-03-03 |
| KR950005867A (en) | 1995-03-20 |
| KR100332842B1 (en) | 2002-10-25 |
| CN1109069A (en) | 1995-09-27 |
| JP3285278B2 (en) | 2002-05-27 |
| EP0638357A2 (en) | 1995-02-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |