CA1076743A - POLYMERIZATION OF .epsilon.-CAPROLACTAM - Google Patents
POLYMERIZATION OF .epsilon.-CAPROLACTAMInfo
- Publication number
- CA1076743A CA1076743A CA266,548A CA266548A CA1076743A CA 1076743 A CA1076743 A CA 1076743A CA 266548 A CA266548 A CA 266548A CA 1076743 A CA1076743 A CA 1076743A
- Authority
- CA
- Canada
- Prior art keywords
- caprolactam
- polymerization
- epsilon
- temperature
- pressure
- 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.)
- Expired
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Classifications
-
- 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
- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
- C08G69/08—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino-carboxylic acids
- C08G69/14—Lactams
- C08G69/16—Preparatory processes
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polyamides (AREA)
Abstract
O.Z. 31,765 ABSTRACT OF THE DISCLOSURE
An improved process for the continuous polymerization of .epsilon.-capro-lactam in the presence of water as initiator in a vertical down-ward-flow tubular reactor, in which the .epsilon.-caprolactam is partially polymerized at elevated temperature in a first, mechanically agi-tated reaction zone and is further polymerized in further reaction zones to the desired degree of polymerization. Poly-.epsilon.-caprolactam is discharged in the form of a melt. The polymerization is carried out at a gauge pressure of from 0.2 to 0.9 bar, constant in all reaction zones. The temperature in the first reaction zone is from 260 to 295°C whilst obeying the condition t ? 265 + 43 p °C, wherep is the numerical value of the gauge pressure in bars.
An improved process for the continuous polymerization of .epsilon.-capro-lactam in the presence of water as initiator in a vertical down-ward-flow tubular reactor, in which the .epsilon.-caprolactam is partially polymerized at elevated temperature in a first, mechanically agi-tated reaction zone and is further polymerized in further reaction zones to the desired degree of polymerization. Poly-.epsilon.-caprolactam is discharged in the form of a melt. The polymerization is carried out at a gauge pressure of from 0.2 to 0.9 bar, constant in all reaction zones. The temperature in the first reaction zone is from 260 to 295°C whilst obeying the condition t ? 265 + 43 p °C, wherep is the numerical value of the gauge pressure in bars.
Description
1076743 o.z. 31,765 POLYMERIZATION OF -CAPROLACTAM
It ls well known to manufacture poly-~-caprolaotam by continu-ous polymerlzatlon at elevated temperature and atmospherlc pressure ln vertlcal downward-flow polymerlzatlon tubes, so-called VK tubes, whlch may be subdlvlded lnto zones or sections. It ls also known to stlr the lactam melt ln the ~lrst polymerlzatlon zone by mechanl-cal means (c~. German Published Application DAS 1,495,198). In this ~lrst polymerization zone, it is virtually impossible to exceed temperatures o~ 260C, since otherwise the losses would be too great on account Or the volatillty of ~-caprolactam, particularly in the presence o~ water, and also the polymerization rate would ~all ; considerably since some of the water used as lnltiatar evaporates.
Thus statements to the e~ect that the caprolactam melt is heated to ~rom 240 to 280C may be understood only to mean that the melt is lnitlally heated to about 240 to 250C, the temperature being raised to more than 260C only as polymerization proceeds. The contlnuous polymerlzation Or -caprolactam ln VK tubes gives poly--caProlactam of good quality but the process requires long reac-tion times, e.g. ~rom 15 to 20 hours.
.... .. . .
1076743 o.z. 31,765 In addltlon to the contlnuous polymerlzatlon in VK tubes at atmospherlc pressure, continuous processes are known whioh make use of one or more pressure stages. German Patent 916,589 describes a process for the contlnuous manufacture Or polyamldes in whlch the polymerizlng melt passes a number o~ tlmes from a stage of higher pressure to a stage o~ lower pressure. In this multl-stage process, the individual reactlon stages are alternately lnterconnected by means ~or reducing and lncreaslng the pressure. Such a method is compllcated and is not readlly appllcable to VK tubes. U.S. Patent 763,746 descrlbes a process for the contlnuous polymerizatlon of ~-caprolactam in which polymerlzatlon ls carrled out ln a sealed, completely fllled vessel at elevated temperature and elevated pressure ln the presence o~ not more than 1% o~ water as the sole agent ~or acceleratlng the reactlon. Slnce thls process operates wlthout chaln stoppers and must be followed by direct splnnlng, lt ls not sultable for unlversal use. The process ls carrled out at pressures o~ from 5 to 35 atmospheres, l.e. pressures ~or whlch conventlonal VK tubes are not bullt.
It is there~ore desirable to accelerate the reactlon ln the contlnuous polymerizatlon ln VK tubes, ln order to lmprove the space-tlme yleld, although, of course, the quallty of the polymer must remaln unchanged compared wlth conventlonal polymers.
- We have now found that ~-caprolactam ls polymerlzed ln a very much shorter tlme, ln the presence of water as lnltlator, ln a vertlcal, downward-~low tubular reactor ln whlch the caprolactam ls partlally polymerlzed at elevated tempèrature ln a flrst, mecha-nlcally agltated reactlon zone and ls further polymerized ln ~urther reactlon zones to the desired degree o~ polymerizatlon followed by dlscharge of molten poly-~-caprolactam, lf the polymerlzatlon is carried out at a gauge pressure of from 0.2 to 0.9 bar, constant in all reaction zones, and the temperature in the flrst reaction zone is malntalned wlthin the range o~ ~rom 260 to 295C subject to the condition t c 265 + 43 p C, where p is the numerlcal value ~ 67 43 O.Z. 31,765 o~ the pressure ln bars.
The polymerlzation takes place in a vertical, downward-~low tubular reactor such as is frequently descrlbed in the llterature as a VK tube. In the first polymerlzatlon zone, which takes up ~rom about 20 to 40% of the volume of the tubular reactor, partlal polymerization takes place to convert from about 20 to 70% o~ the caprolactam melt to polymer. In this flrst zone the melt ls stlrred mechanlcally. Polymerization is contlnued to the deslred degree ln a plurallty of subsequent reactlon zones ln whlch the tempera- -ture is controlled fairl~ accurately, usually by means Or heat exchangers, glvlng temperatures Or rrom 260 to 300C ln the second reactlon zone, the temperature then belng reduced in the subsequent zones until it is from about 240 to 280C at dlscharge. Sald dls-charge may be carrled out, for example, by means or worms or gear ; pumps~ The polymer ls then obtalned ln the form Or a tape or flla-ments and granulatedO Alternatlvely, a spinning unlt may follow directly on the polymerlzatlon reactor.
In accordance wlth the present lnventlon, a constant gauge pressure Or from 0.2 to 0.9 bar and preferably from 0.25 to 0.75 bar ls malntalned ln the reactor throughout, i.e. includlng the flrst polymerlzatlon zone. Strlctly speaking, Or course, different points of the reactor are at somewhat dlfferent pressures, since the statlc pressure of the llquld column ls not negliglble.
The values Or the gauge pressure stated relate to the gas space above the first reaction zone. The pressure ln the melt at each point ls hlgher by the value Or the hydrostatic pressure Or the llquld column above sald polnt. The melt is rlashed to atmospheric pressure when dlscharged from the VK tube.
The gas space above the flrst reactlon zone ls filtered wlth caprolactam vapor, steam and, posslbly, inert gases used for purglng, e.g. nitrogen. The deslred pressure may be obtained by increaslng the temperature of the flrst reactlon zone and seallng off the gas space from the atmosphere. Where purglng gas is used, it is also , . .. .
.
.
107~743 O.Z. 31,5765 possible to create the desired pressure by forcing in a suitable amount of purging gas and then raising the temperature to the desired value. The desired pressure may be malntalned, for example by seal-lng of~ the gas chamber above the melt in the first reaction zone ~rom the atmosphere by means of a dip tube provided at a sultable level. Alternatively, the pressure may be malntalned constant by means o~ a regulator valve. The inert gases used for purging the gas chamber may escape through the dlp tube or regulator valve.
In addltion to the water required as lnitiator, use may be made of chaln stoppers, acceleratorsJ modlfying comonomers, stabillzers, delustrants and other addltives ln known manner.
Water is used, as initiator, in an amount of at least 0.2%
by weight and preferably of from 0.4 to 0.7% by welght, based on the caprolactam introduced. Excess water can evaporate from the first reaction zone. Larger amounts of water than those stated are general-ly undeslrable, slnce large additional amounts of heat must be applied to evaporate the excess water. However, larger amounts of water, for example up to 15~, may be used ln special cases, for example as carrlers for the introduction of one of the above addi-tives, e.g. an accelerator or delustrant.
Due to the use o~ the sald superatmospherlc pressure, it ispossible to malntain temperatures of more than 260C in the flrst polymerization zone without evaporatlng the water necessary for the progress of the polymerlzation. If the process is carried out at atmospheric pressure, these temperatures cannot be achieved in the first polymerization zone.
The process may be carried out using conventional VK tubes in which the first reaction zone is stirred mechanically and the tem-perature in the subsequent polymerization zones is controlled ~0 relatively accurately within the limits stated. Conventional baffles may be used to control the flow pattern. .
Our novel process makes it possible to operate VK tubes in an extremely flexible manner andin particular to increase the polymeri-_~ _ .. . . . . .
. . ' ' ~
1C~'76'7~3 O.Z. 31,576 zation capacity thereof, i.e. improve the space-tlme yield, at very low equlpment costs. The process ls further illustrated wlth refer-ence to the following Examples. To chara¢terize the pro~lucts, the solution viscosity was determined after extracting the low molecular welght portlons wlth hot water and drylng the product. The sald vls-coslty ls glven as the relative vlscosity of a 1% solutlon of the polyamide in 96% sulfuric acid at 25C.
Polycaprolactam obtained by the process of the lnvention ls sultable for the manufacture of filaments, fibersJ wire and in~ec-tion molded or extruded shaped articles.
Use was made of a heated VK tube in whlch the top (first) reaction zone was agitated by means of a stirrer and the tempera-ture in the reactlon zones below said first reaction zone may be controlled by means of heat exchangers. The superatmospheric pressure was adjusted by means of a dip tube between the gas chamber above the flrst reaction zone and the atmosphere. The capaclty of the VK
tube was 270 liters, the first, stirred, reaction zone o¢cupying 70 l.
Molten caprolactam having a content of 0.5% by weight of water was fed to the top of the VK tube at a gauge pressure of 0.26 bar àrid at a rate of 22 kg/hr. The temperature in the flrst, stirred, reaction zone was 270C. The heat of polymerization liberated in the subsequent reactlon zones was removed by approprlate cooling using heat exchangers so that the temperature of the melt enterin~s the discharge pump was again 270C. The product had a content of extractable low molecular weight portions of 12.7% and a relative vlscosity of 3.01 (after extraction and drying). The properties were approximately the same as those of the product obtained in the following comparative test.
The comparative test was carried out at atmospheric pressure, a feed rate of 18 kg/hr and a temperature of 257C in the first reaction zone, all other conditions being identical. The content of 1076743 o.z. 31J 765 extractables was 12.4% and the relatlve vlscoslty was ~.0~. Thus the condltions used ln Example 1 provlde an lncrease in polymerizatlon capacity from 18 to 22 kg/hr,~l.e. about 22%.
Molten caprolactam havlng a content of from 0.5% by weight Or water as lnitlator and 0.15% by welght o~ proplonlc aold as chaln stopper was red to the VK ~ube of Example 1 at a rate Or 20 kg/hr and a gauge pressure Or 0.26 bar. The temperature in the rlrst reactlon zone was 270C and the temperature Or the product enter-lng the dlscharge pump was 266C. The product had a content Or extractables Or 10.9% and a relatlve viscoslty Or 2.59.
The test Or Example 2 was repeated at a temperature Or 274C
ln the rlrst reactlon zone, all other conditlons belng ldentlcal. .
The product had a content Or extractables Or 12.6% and a relatlve vlscoslty Or 2.67. Increase ln the temperature Or the flrst reac-tlon zone from 270 to 274C causedJ thererore, a certaln lncrease ln the content o~ extraotables. Further lncrease ln the temperature beyond that glven by the relatlonshlp t ~ 265 + 43 p (t = 276.1C
at 0.26 bar) leads to a rurther lncrease ln the content of extract-ables, whlch ls undeslrable.
EXAMPLE 4 ~ .
Caprolactam having a content Or 0.5% Or water and 0.15% Or -proplonlc acld was fed to the VK tube Or Example 1 at a rate of 30.5 kg/hr and a gauge pressure of 0.75 bar. The temperature ln the flrst reactlon zone was 288C and that Or the melt enterlng the discharge pump was 270C. The product had a content Or extractables of 12.3~ and a relatlve vlscoslty Or 2.50. No damage to the product was discernible and.the color Or the product was satisfactory.
_~_ ~., .
., - . - . ~ . . ..
; . - :
,
It ls well known to manufacture poly-~-caprolaotam by continu-ous polymerlzatlon at elevated temperature and atmospherlc pressure ln vertlcal downward-flow polymerlzatlon tubes, so-called VK tubes, whlch may be subdlvlded lnto zones or sections. It ls also known to stlr the lactam melt ln the ~lrst polymerlzatlon zone by mechanl-cal means (c~. German Published Application DAS 1,495,198). In this ~lrst polymerization zone, it is virtually impossible to exceed temperatures o~ 260C, since otherwise the losses would be too great on account Or the volatillty of ~-caprolactam, particularly in the presence o~ water, and also the polymerization rate would ~all ; considerably since some of the water used as lnltiatar evaporates.
Thus statements to the e~ect that the caprolactam melt is heated to ~rom 240 to 280C may be understood only to mean that the melt is lnitlally heated to about 240 to 250C, the temperature being raised to more than 260C only as polymerization proceeds. The contlnuous polymerlzation Or -caprolactam ln VK tubes gives poly--caProlactam of good quality but the process requires long reac-tion times, e.g. ~rom 15 to 20 hours.
.... .. . .
1076743 o.z. 31,765 In addltlon to the contlnuous polymerlzatlon in VK tubes at atmospherlc pressure, continuous processes are known whioh make use of one or more pressure stages. German Patent 916,589 describes a process for the contlnuous manufacture Or polyamldes in whlch the polymerizlng melt passes a number o~ tlmes from a stage of higher pressure to a stage o~ lower pressure. In this multl-stage process, the individual reactlon stages are alternately lnterconnected by means ~or reducing and lncreaslng the pressure. Such a method is compllcated and is not readlly appllcable to VK tubes. U.S. Patent 763,746 descrlbes a process for the contlnuous polymerizatlon of ~-caprolactam in which polymerlzatlon ls carrled out ln a sealed, completely fllled vessel at elevated temperature and elevated pressure ln the presence o~ not more than 1% o~ water as the sole agent ~or acceleratlng the reactlon. Slnce thls process operates wlthout chaln stoppers and must be followed by direct splnnlng, lt ls not sultable for unlversal use. The process ls carrled out at pressures o~ from 5 to 35 atmospheres, l.e. pressures ~or whlch conventlonal VK tubes are not bullt.
It is there~ore desirable to accelerate the reactlon ln the contlnuous polymerizatlon ln VK tubes, ln order to lmprove the space-tlme yleld, although, of course, the quallty of the polymer must remaln unchanged compared wlth conventlonal polymers.
- We have now found that ~-caprolactam ls polymerlzed ln a very much shorter tlme, ln the presence of water as lnltlator, ln a vertlcal, downward-~low tubular reactor ln whlch the caprolactam ls partlally polymerlzed at elevated tempèrature ln a flrst, mecha-nlcally agltated reactlon zone and ls further polymerized ln ~urther reactlon zones to the desired degree o~ polymerizatlon followed by dlscharge of molten poly-~-caprolactam, lf the polymerlzatlon is carried out at a gauge pressure of from 0.2 to 0.9 bar, constant in all reaction zones, and the temperature in the flrst reaction zone is malntalned wlthin the range o~ ~rom 260 to 295C subject to the condition t c 265 + 43 p C, where p is the numerlcal value ~ 67 43 O.Z. 31,765 o~ the pressure ln bars.
The polymerlzation takes place in a vertical, downward-~low tubular reactor such as is frequently descrlbed in the llterature as a VK tube. In the first polymerlzatlon zone, which takes up ~rom about 20 to 40% of the volume of the tubular reactor, partlal polymerization takes place to convert from about 20 to 70% o~ the caprolactam melt to polymer. In this flrst zone the melt ls stlrred mechanlcally. Polymerization is contlnued to the deslred degree ln a plurallty of subsequent reactlon zones ln whlch the tempera- -ture is controlled fairl~ accurately, usually by means Or heat exchangers, glvlng temperatures Or rrom 260 to 300C ln the second reactlon zone, the temperature then belng reduced in the subsequent zones until it is from about 240 to 280C at dlscharge. Sald dls-charge may be carrled out, for example, by means or worms or gear ; pumps~ The polymer ls then obtalned ln the form Or a tape or flla-ments and granulatedO Alternatlvely, a spinning unlt may follow directly on the polymerlzatlon reactor.
In accordance wlth the present lnventlon, a constant gauge pressure Or from 0.2 to 0.9 bar and preferably from 0.25 to 0.75 bar ls malntalned ln the reactor throughout, i.e. includlng the flrst polymerlzatlon zone. Strlctly speaking, Or course, different points of the reactor are at somewhat dlfferent pressures, since the statlc pressure of the llquld column ls not negliglble.
The values Or the gauge pressure stated relate to the gas space above the first reaction zone. The pressure ln the melt at each point ls hlgher by the value Or the hydrostatic pressure Or the llquld column above sald polnt. The melt is rlashed to atmospheric pressure when dlscharged from the VK tube.
The gas space above the flrst reactlon zone ls filtered wlth caprolactam vapor, steam and, posslbly, inert gases used for purglng, e.g. nitrogen. The deslred pressure may be obtained by increaslng the temperature of the flrst reactlon zone and seallng off the gas space from the atmosphere. Where purglng gas is used, it is also , . .. .
.
.
107~743 O.Z. 31,5765 possible to create the desired pressure by forcing in a suitable amount of purging gas and then raising the temperature to the desired value. The desired pressure may be malntalned, for example by seal-lng of~ the gas chamber above the melt in the first reaction zone ~rom the atmosphere by means of a dip tube provided at a sultable level. Alternatively, the pressure may be malntalned constant by means o~ a regulator valve. The inert gases used for purging the gas chamber may escape through the dlp tube or regulator valve.
In addltion to the water required as lnitiator, use may be made of chaln stoppers, acceleratorsJ modlfying comonomers, stabillzers, delustrants and other addltives ln known manner.
Water is used, as initiator, in an amount of at least 0.2%
by weight and preferably of from 0.4 to 0.7% by welght, based on the caprolactam introduced. Excess water can evaporate from the first reaction zone. Larger amounts of water than those stated are general-ly undeslrable, slnce large additional amounts of heat must be applied to evaporate the excess water. However, larger amounts of water, for example up to 15~, may be used ln special cases, for example as carrlers for the introduction of one of the above addi-tives, e.g. an accelerator or delustrant.
Due to the use o~ the sald superatmospherlc pressure, it ispossible to malntain temperatures of more than 260C in the flrst polymerization zone without evaporatlng the water necessary for the progress of the polymerlzation. If the process is carried out at atmospheric pressure, these temperatures cannot be achieved in the first polymerization zone.
The process may be carried out using conventional VK tubes in which the first reaction zone is stirred mechanically and the tem-perature in the subsequent polymerization zones is controlled ~0 relatively accurately within the limits stated. Conventional baffles may be used to control the flow pattern. .
Our novel process makes it possible to operate VK tubes in an extremely flexible manner andin particular to increase the polymeri-_~ _ .. . . . . .
. . ' ' ~
1C~'76'7~3 O.Z. 31,576 zation capacity thereof, i.e. improve the space-tlme yield, at very low equlpment costs. The process ls further illustrated wlth refer-ence to the following Examples. To chara¢terize the pro~lucts, the solution viscosity was determined after extracting the low molecular welght portlons wlth hot water and drylng the product. The sald vls-coslty ls glven as the relative vlscosity of a 1% solutlon of the polyamide in 96% sulfuric acid at 25C.
Polycaprolactam obtained by the process of the lnvention ls sultable for the manufacture of filaments, fibersJ wire and in~ec-tion molded or extruded shaped articles.
Use was made of a heated VK tube in whlch the top (first) reaction zone was agitated by means of a stirrer and the tempera-ture in the reactlon zones below said first reaction zone may be controlled by means of heat exchangers. The superatmospheric pressure was adjusted by means of a dip tube between the gas chamber above the flrst reaction zone and the atmosphere. The capaclty of the VK
tube was 270 liters, the first, stirred, reaction zone o¢cupying 70 l.
Molten caprolactam having a content of 0.5% by weight of water was fed to the top of the VK tube at a gauge pressure of 0.26 bar àrid at a rate of 22 kg/hr. The temperature in the flrst, stirred, reaction zone was 270C. The heat of polymerization liberated in the subsequent reactlon zones was removed by approprlate cooling using heat exchangers so that the temperature of the melt enterin~s the discharge pump was again 270C. The product had a content of extractable low molecular weight portions of 12.7% and a relative vlscosity of 3.01 (after extraction and drying). The properties were approximately the same as those of the product obtained in the following comparative test.
The comparative test was carried out at atmospheric pressure, a feed rate of 18 kg/hr and a temperature of 257C in the first reaction zone, all other conditions being identical. The content of 1076743 o.z. 31J 765 extractables was 12.4% and the relatlve vlscoslty was ~.0~. Thus the condltions used ln Example 1 provlde an lncrease in polymerizatlon capacity from 18 to 22 kg/hr,~l.e. about 22%.
Molten caprolactam havlng a content of from 0.5% by weight Or water as lnitlator and 0.15% by welght o~ proplonlc aold as chaln stopper was red to the VK ~ube of Example 1 at a rate Or 20 kg/hr and a gauge pressure Or 0.26 bar. The temperature in the rlrst reactlon zone was 270C and the temperature Or the product enter-lng the dlscharge pump was 266C. The product had a content Or extractables Or 10.9% and a relatlve viscoslty Or 2.59.
The test Or Example 2 was repeated at a temperature Or 274C
ln the rlrst reactlon zone, all other conditlons belng ldentlcal. .
The product had a content Or extractables Or 12.6% and a relatlve vlscoslty Or 2.67. Increase ln the temperature Or the flrst reac-tlon zone from 270 to 274C causedJ thererore, a certaln lncrease ln the content o~ extraotables. Further lncrease ln the temperature beyond that glven by the relatlonshlp t ~ 265 + 43 p (t = 276.1C
at 0.26 bar) leads to a rurther lncrease ln the content of extract-ables, whlch ls undeslrable.
EXAMPLE 4 ~ .
Caprolactam having a content Or 0.5% Or water and 0.15% Or -proplonlc acld was fed to the VK tube Or Example 1 at a rate of 30.5 kg/hr and a gauge pressure of 0.75 bar. The temperature ln the flrst reactlon zone was 288C and that Or the melt enterlng the discharge pump was 270C. The product had a content Or extractables of 12.3~ and a relatlve vlscoslty Or 2.50. No damage to the product was discernible and.the color Or the product was satisfactory.
_~_ ~., .
., - . - . ~ . . ..
; . - :
,
Claims (5)
1. An improved process for the continuous polymerization of .epsilon.-caprolactam in the presence of water as initiator in a vertical downward-flow tubular reactor in which the .epsilon.-caprolactam is partially polymerized at elevated temperature in a first reaction zone, mechanically agitated, and is further polymerized in further reac-tion zones until the desired degree of polymerization has been achieved, molten poly-.epsilon.-caprolactam then being discharged, wherein the improvement consists in that polymerization is carried out at a gauge pressure of from 0.2 to 0.9 bar, constant in all reaction zones, and the temperature in the first reaction zone is maintained within the range of from 260 to 295°C subject to the condition t ? 265 + 43 p °C, where p is the numerical value of the pressure in bars.
2. A process as claimed in claim 1, wherein from 20 to 70% of the molten caprolactam is converted to polymer in the first reac-tion zone.
3. A process as claimed in claim 1, wherein the temperature in the second reaction zone is from 260 to 300°C and the temperature in subsequent zones is reduced progressively until it has a value of from 240 to 280°C at discharge.
4. A process as claimed in claim 1, wherein the pressure used is from 0.25 to 0.75 bar.
5. A process as claimed in claim 1 wherein water is used as initiator in an amount of from 0.4 to 0.7% by weight, based on capro-lactam used.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19752558480 DE2558480C2 (en) | 1975-12-24 | 1975-12-24 | Process for the polymerization of epsilon-caprolactam |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1076743A true CA1076743A (en) | 1980-04-29 |
Family
ID=5965511
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA266,548A Expired CA1076743A (en) | 1975-12-24 | 1976-11-25 | POLYMERIZATION OF .epsilon.-CAPROLACTAM |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS6026139B2 (en) |
| BE (1) | BE849851A (en) |
| CA (1) | CA1076743A (en) |
| CH (1) | CH602825A5 (en) |
| DE (1) | DE2558480C2 (en) |
| FR (1) | FR2336432A1 (en) |
| GB (1) | GB1563933A (en) |
| IT (1) | IT1067286B (en) |
| NL (1) | NL180431C (en) |
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| EP3390622B1 (en) | 2015-12-17 | 2020-05-13 | Evonik Operations GmbH | A genetically modified acetogenic cell |
| JP2019523271A (en) | 2016-07-27 | 2019-08-22 | エボニック デグサ ゲーエムベーハーＥｖｏｎｉｋ Ｄｅｇｕｓｓａ ＧｍｂＨ | N-acetylhomoserine |
| CN116261581A (en) | 2020-12-17 | 2023-06-13 | 巴斯夫欧洲公司 | Selective depolymerization of polyamide 6 from a mixture of a caprolactam-containing polymer and a polyurethane-containing polymer, in particular a polyurethane block copolymer, to obtain caprolactam |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL134637C (en) * | 1961-06-21 | |||
| DE1495198B2 (en) * | 1964-09-17 | 1974-04-11 | Basf Ag, 6700 Ludwigshafen | Process for the continuous production of polylactams |
-
1975
- 1975-12-24 DE DE19752558480 patent/DE2558480C2/en not_active Expired
-
1976
- 1976-11-25 CA CA266,548A patent/CA1076743A/en not_active Expired
- 1976-11-26 IT IT2986776A patent/IT1067286B/en active
- 1976-12-20 NL NL7614154A patent/NL180431C/en not_active IP Right Cessation
- 1976-12-21 CH CH1609676A patent/CH602825A5/xx not_active IP Right Cessation
- 1976-12-22 FR FR7638648A patent/FR2336432A1/en active Granted
- 1976-12-22 GB GB5349076A patent/GB1563933A/en not_active Expired
- 1976-12-24 BE BE173627A patent/BE849851A/en not_active IP Right Cessation
- 1976-12-24 JP JP15515876A patent/JPS6026139B2/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9080259B2 (en) | 2009-06-30 | 2015-07-14 | Basf Se | Polyamide fibers with dyeable particles and production thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2336432B1 (en) | 1980-03-28 |
| NL7614154A (en) | 1977-06-28 |
| NL180431B (en) | 1986-09-16 |
| JPS5280397A (en) | 1977-07-06 |
| DE2558480A1 (en) | 1977-07-07 |
| DE2558480C2 (en) | 1985-03-07 |
| CH602825A5 (en) | 1978-08-15 |
| FR2336432A1 (en) | 1977-07-22 |
| NL180431C (en) | 1987-02-16 |
| IT1067286B (en) | 1985-03-16 |
| BE849851A (en) | 1977-06-24 |
| GB1563933A (en) | 1980-04-02 |
| JPS6026139B2 (en) | 1985-06-21 |
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