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About the structure process analysis of twin screw extruder

About the structure process analysis of twin screw extruder

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  • Time of issue:2020-07-30 17:49
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(Summary description)Next,theeditorofJuliwillgiveyouabriefintroductionaboutthestructureandprocessanalysisofthetwin-screwextruder:  1.Plasticizingarea  Theplasticizingzoneistoheattheinjectedresintoformamoltenstate.Theconditionssuchastheheatingtemperatureandtimeinthisregionarenotparticularlylimitedaslongasthefluoropolymerhavingaspecificunstableterminalgroupisinamoltenstate.Inthelatterhalfoftheplasticizationzone,itispreferabletoprovidedevolatilizationholestoremoveatleastapartofvolatilecomponentsundernormalpressureorreducedpressure.Then,thepartialpressureofvolatilecomponentsinthestabilizationregiondescribedlatercanbereduced,andthestabilizationtreatmentcanbeeffectivelypromoted.  2.Stabilizationtreatmentarea  ThestabilizationzoneistomeltandkneadandconvertspecificunstableendgroupsintoaCF2H.Thestabilizationtreatmentareaispreferablyformedbyusingakneadingdiscwithoutpropulsion.Here,melt-kneadingiscarriedoutinthepresenceofwaterandoxygen.Itcandirectlyintroducepurewater,ionexchangewater,etc.orwatervapor;itcanalsobeaccompaniedbythefluoropolymertobetreated.Theamountofwateraddedisthesameasthenumberofunstableterminalgroups,butitisactuallypreferabletosupplyanexcessamount,forexample,atleast10timestheamount.Thepressureinthestabilizationzoneisgenerallycontrolledat0.2~10MPa,andthesettemperatureiscontrolledat280~430℃.Thetimetomaintainpressurizationisusuallylessthan10minutes.  Accordingtotheprincipleoftheextrudertoremoveunstableendgroups,themelt-kneadinginthestabilizationzoneispreferablycarriedoutinthepresenceofoxygeninadditiontothepresenceofwater.Airisusuallyusedintermsofeconomy.Inthepresenceofoxygen,thecarbongeneratedbythemoltenkneadedproductisalsoburned,whichcaninhibitthecoloringofthefluoropolymer.Oxygenisaninertgastotheunstableterminalgroupscarboxylandfluorinatedacylgroups.Duringtheprocessofmeltingandkneading,itcanimprovethedevolatilizationefficiencyofvolatilecomponents.  Three,devolatilizationarea  Thedevolatilizationzoneremoveshigh-temperaturevolatilecomponentsgeneratedbythedecompositionofspecificunstableterminalgroups.Theabsolutepressurevariesaccordingtothemoltenstateofthemoltenkneadedproductandtheoperatingconditionsofthescrewofthekneader.Generally,thepressureisreducedtothepointwherethemoltenkneadedproductdoesnotintrudeintotheexhaustnozzle.Itcanbe0.01to0.1MPa,andthetemperatureiscontrolledat25O~Claughataround.  Inthepresenceofacertainamountofwaterandoxygen,FEPextrudingthroughatwin-screwextrudercaneffectivelyremovetheunstableterminalgroupsofFEP.SimplifiestheprocessingprocessofFEPunstableendgroupsandsavesproductioncosts.Whentheobtainedstabilizedpolymerismelt-formed,nobubblesorvoidsaregeneratedinthefinishedproduct,anditisnotcolored. Formoreinformationabouttwinscrewextruders,pleasevisithttp://www.njjl.com/

About the structure process analysis of twin screw extruder

(Summary description)Next,theeditorofJuliwillgiveyouabriefintroductionaboutthestructureandprocessanalysisofthetwin-screwextruder:  1.Plasticizingarea  Theplasticizingzoneistoheattheinjectedresintoformamoltenstate.Theconditionssuchastheheatingtemperatureandtimeinthisregionarenotparticularlylimitedaslongasthefluoropolymerhavingaspecificunstableterminalgroupisinamoltenstate.Inthelatterhalfoftheplasticizationzone,itispreferabletoprovidedevolatilizationholestoremoveatleastapartofvolatilecomponentsundernormalpressureorreducedpressure.Then,thepartialpressureofvolatilecomponentsinthestabilizationregiondescribedlatercanbereduced,andthestabilizationtreatmentcanbeeffectivelypromoted.  2.Stabilizationtreatmentarea  ThestabilizationzoneistomeltandkneadandconvertspecificunstableendgroupsintoaCF2H.Thestabilizationtreatmentareaispreferablyformedbyusingakneadingdiscwithoutpropulsion.Here,melt-kneadingiscarriedoutinthepresenceofwaterandoxygen.Itcandirectlyintroducepurewater,ionexchangewater,etc.orwatervapor;itcanalsobeaccompaniedbythefluoropolymertobetreated.Theamountofwateraddedisthesameasthenumberofunstableterminalgroups,butitisactuallypreferabletosupplyanexcessamount,forexample,atleast10timestheamount.Thepressureinthestabilizationzoneisgenerallycontrolledat0.2~10MPa,andthesettemperatureiscontrolledat280~430℃.Thetimetomaintainpressurizationisusuallylessthan10minutes.  Accordingtotheprincipleoftheextrudertoremoveunstableendgroups,themelt-kneadinginthestabilizationzoneispreferablycarriedoutinthepresenceofoxygeninadditiontothepresenceofwater.Airisusuallyusedintermsofeconomy.Inthepresenceofoxygen,thecarbongeneratedbythemoltenkneadedproductisalsoburned,whichcaninhibitthecoloringofthefluoropolymer.Oxygenisaninertgastotheunstableterminalgroupscarboxylandfluorinatedacylgroups.Duringtheprocessofmeltingandkneading,itcanimprovethedevolatilizationefficiencyofvolatilecomponents.  Three,devolatilizationarea  Thedevolatilizationzoneremoveshigh-temperaturevolatilecomponentsgeneratedbythedecompositionofspecificunstableterminalgroups.Theabsolutepressurevariesaccordingtothemoltenstateofthemoltenkneadedproductandtheoperatingconditionsofthescrewofthekneader.Generally,thepressureisreducedtothepointwherethemoltenkneadedproductdoesnotintrudeintotheexhaustnozzle.Itcanbe0.01to0.1MPa,andthetemperatureiscontrolledat25O~Claughataround.  Inthepresenceofacertainamountofwaterandoxygen,FEPextrudingthroughatwin-screwextrudercaneffectivelyremovetheunstableterminalgroupsofFEP.SimplifiestheprocessingprocessofFEPunstableendgroupsandsavesproductioncosts.Whentheobtainedstabilizedpolymerismelt-formed,nobubblesorvoidsaregeneratedinthefinishedproduct,anditisnotcolored. Formoreinformationabouttwinscrewextruders,pleasevisithttp://www.njjl.com/

  • Categories:company news
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  • Time of issue:2020-07-30 17:49
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Next, the editor of Juli will give you a brief introduction about the structure and process analysis of the twin-screw extruder:
    1. Plasticizing area
    The plasticizing zone is to heat the injected resin to form a molten state. The conditions such as the heating temperature and time in this region are not particularly limited as long as the fluoropolymer having a specific unstable terminal group is in a molten state. In the latter half of the plasticization zone, it is preferable to provide devolatilization holes to remove at least a part of volatile components under normal pressure or reduced pressure. Then, the partial pressure of volatile components in the stabilization region described later can be reduced, and the stabilization treatment can be effectively promoted.
    2. Stabilization treatment area
    The stabilization zone is to melt and knead and convert specific unstable end groups into a CF2 H. The stabilization treatment area is preferably formed by using a kneading disc without propulsion. Here, melt-kneading is carried out in the presence of water and oxygen. It can directly introduce pure water, ion exchange water, etc. or water vapor; it can also be accompanied by the fluoropolymer to be treated.
The amount of water added is the same as the number of unstable terminal groups, but it is actually preferable to supply an excess amount, for example, at least 10 times the amount. The pressure in the stabilization zone is generally controlled at 0.2~10MPa, and the set temperature is controlled at 280~430℃. The time to maintain pressurization is usually less than 10 minutes.
   According to the principle of the extruder to remove unstable end groups, the melt-kneading in the stabilization zone is preferably carried out in the presence of oxygen in addition to the presence of water. Air is usually used in terms of economy. In the presence of oxygen, the carbon generated by the molten kneaded product is also burned, which can inhibit the coloring of the fluoropolymer. Oxygen is an inert gas to the unstable terminal groups carboxyl and fluorinated acyl groups. During the process of melting and kneading, it can improve the devolatilization efficiency of volatile components.
   Three, devolatilization area
   The devolatilization zone removes high-temperature volatile components generated by the decomposition of specific unstable terminal groups. The absolute pressure varies according to the molten state of the molten kneaded product and the operating conditions of the screw of the kneader. Generally, the pressure is reduced to the point where the molten kneaded product does not intrude into the exhaust nozzle. It can be 0.01 to 0.1 MPa, and the temperature is controlled at 25O~C laugh at around.
   In the presence of a certain amount of water and oxygen, FEP extruding through a twin-screw extruder can effectively remove the unstable terminal groups of FEP. Simplifies the processing process of FEP unstable end groups and saves production costs. When the obtained stabilized polymer is melt-formed, no bubbles or voids are generated in the finished product, and it is not colored.
 
For more information about twin screw extruders, please visit http://www.njjl.com/

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About the structure process analysis of twin screw extruder

About the structure process analysis of twin screw extruder

Next,theeditorofJuliwillgiveyouabriefintroductionaboutthestructureandprocessanalysisofthetwin-screwextruder:  1.Plasticizingarea  Theplasticizingzoneistoheattheinjectedresintoformamoltenstate.Theconditionssuchastheheatingtemperatureandtimeinthisregionarenotparticularlylimitedaslongasthefluoropolymerhavingaspecificunstableterminalgroupisinamoltenstate.Inthelatterhalfoftheplasticizationzone,itispreferabletoprovidedevolatilizationholestoremoveatleastapartofvolatilecomponentsundernormalpressureorreducedpressure.Then,thepartialpressureofvolatilecomponentsinthestabilizationregiondescribedlatercanbereduced,andthestabilizationtreatmentcanbeeffectivelypromoted.  2.Stabilizationtreatmentarea  ThestabilizationzoneistomeltandkneadandconvertspecificunstableendgroupsintoaCF2H.Thestabilizationtreatmentareaispreferablyformedbyusingakneadingdiscwithoutpropulsion.Here,melt-kneadingiscarriedoutinthepresenceofwaterandoxygen.Itcandirectlyintroducepurewater,ionexchangewater,etc.orwatervapor;itcanalsobeaccompaniedbythefluoropolymertobetreated.Theamountofwateraddedisthesameasthenumberofunstableterminalgroups,butitisactuallypreferabletosupplyanexcessamount,forexample,atleast10timestheamount.Thepressureinthestabilizationzoneisgenerallycontrolledat0.2~10MPa,andthesettemperatureiscontrolledat280~430℃.Thetimetomaintainpressurizationisusuallylessthan10minutes.  Accordingtotheprincipleoftheextrudertoremoveunstableendgroups,themelt-kneadinginthestabilizationzoneispreferablycarriedoutinthepresenceofoxygeninadditiontothepresenceofwater.Airisusuallyusedintermsofeconomy.Inthepresenceofoxygen,thecarbongeneratedbythemoltenkneadedproductisalsoburned,whichcaninhibitthecoloringofthefluoropolymer.Oxygenisaninertgastotheunstableterminalgroupscarboxylandfluorinatedacylgroups.Duringtheprocessofmeltingandkneading,itcanimprovethedevolatilizationefficiencyofvolatilecomponents.  Three,devolatilizationarea  Thedevolatilizationzoneremoveshigh-temperaturevolatilecomponentsgeneratedbythedecompositionofspecificunstableterminalgroups.Theabsolutepressurevariesaccordingtothemoltenstateofthemoltenkneadedproductandtheoperatingconditionsofthescrewofthekneader.Generally,thepressureisreducedtothepointwherethemoltenkneadedproductdoesnotintrudeintotheexhaustnozzle.Itcanbe0.01to0.1MPa,andthetemperatureiscontrolledat25O~Claughataround.  Inthepresenceofacertainamountofwaterandoxygen,FEPextrudingthroughatwin-screwextrudercaneffectivelyremovetheunstableterminalgroupsofFEP.SimplifiestheprocessingprocessofFEPunstableendgroupsandsavesproductioncosts.Whentheobtainedstabilizedpolymerismelt-formed,nobubblesorvoidsaregeneratedinthefinishedproduct,anditisnotcolored. Formoreinformationabouttwinscrewextruders,pleasevisithttp://www.njjl.com/
发布时间 : 2020-07-30 点击 : 0

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