WO2024251758A1 - Procédé de dépolymérisation hydrolytique d'un polyamide - Google Patents

Procédé de dépolymérisation hydrolytique d'un polyamide Download PDF

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Publication number
WO2024251758A1
WO2024251758A1 PCT/EP2024/065380 EP2024065380W WO2024251758A1 WO 2024251758 A1 WO2024251758 A1 WO 2024251758A1 EP 2024065380 W EP2024065380 W EP 2024065380W WO 2024251758 A1 WO2024251758 A1 WO 2024251758A1
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WO
WIPO (PCT)
Prior art keywords
stream
unit
range
polyamide
aqueous
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.)
Ceased
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PCT/EP2024/065380
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English (en)
Inventor
Stefan Blei
Faissal-Ali El-Toufaili
Oliver Bey
Vikram Raghavendhar RAVIKUMAR
Bart Vander Straeten
Michael Schreiber
Bao Liu
Christian Dienes
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BASF SE
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BASF SE
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Publication date
Application filed by BASF SE filed Critical BASF SE
Priority to CN202480037510.8A priority Critical patent/CN121399096A/zh
Priority to AU2024286546A priority patent/AU2024286546A1/en
Priority to KR1020267000456A priority patent/KR20260019627A/ko
Priority to EP24731884.3A priority patent/EP4724421A1/fr
Publication of WO2024251758A1 publication Critical patent/WO2024251758A1/fr
Priority to MX2025014674A priority patent/MX2025014674A/es
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
    • C07D201/02—Preparation of lactams
    • C07D201/12—Preparation of lactams by depolymerising polyamides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • C08J11/14—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with steam or water
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • C08L77/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
    • C08J2377/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/141—Feedstock
    • Y02P20/143—Feedstock the feedstock being recycled material, e.g. plastics
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the present invention relates to a process for hydrolytically depolymerizing a polyamide prepared from c-caprolactam and an apparatus for carrying out a process for hydrolytically depolymerizing a polyamide prepared from c-caprolactam, preferably for carrying out the aforementioned process.
  • Polyamide and in particular polyamide 6 being characterized by the formula (-NH-(CH2)5-CO-) n , can be found in numerous materials, such as packaging, engineering plastics from automotive and textile filaments. The latter represents about 40 % of the polyamide 6 global market. At present, only a very small part of the textile filaments is recycled while it represents a significant percentage of the global CO2 emissions. There is thus a need to recycle polyamide 6 from such materials. Processes for alkaline depolymerizing a polyamide exists. Thus, there is a need to provide an improved process for depolymerizing a polyamide able to overcome these issues.
  • an efficient depolymerization reaction wherein polyamide 6 is hydrolytically hydrolyzed can be realized when upstream of the chemical reaction unit in which the depolymerization reaction actually takes place, a specific sequence of a melting unit and a pre-reaction unit is realized. Further, it was found that the process can be rendered even more efficient if a specific design of the chemical reaction unit is realized. Based thereon, and in combination with specific sequences of stages upstream and in particular downstream of said chemical reaction unit allowing for the recycling of water and a very effective use of process-internal heat, an advantageous overall process for recycling materials containing polyamide 6 can be provided by the present invention.
  • the present invention relates to a process for hydrolytically depolymerizing a polyamide 6 comprised in a solid material M, the process comprising
  • no polyamide 6 depolymerization catalyst such as a mineral acid, such as one or more of hydrochloric acid, nitric acid, sulphuric acid and phosphoric acid, and/or a zinc salt such as zinc chloride, zinc acetate or zinc triflate is added for preparing the stream SF to be subjected to hydrolytic polyamide 6 depolymerisation conditions according to (vi).
  • one or more of the following ranges may be preferred: 0.6 ⁇ TSM/TSF 0.7; 0.7 ⁇ TSM/TSF 0.8;
  • the pre-reaction unit UPR according to (iv) comprises, more preferably consists of a mixing unit, wherein more preferably, said mixing unit is a static mixing unit.
  • static mixing unit refers to an arrangement of mixing elements which are installed in a pipe or duct, and which operate essentially without moving parts, preferably entirely without moving parts. According to the present invention, it may be preferred that said mixing unit is configured as a suitable pipe junction of the pipe for the stream SM and the pipe for the stream Sw, wherein no specific mixing elements are present.
  • Sw and SM are admixed in UPR at a mixing ratio (mw/kg) I (mp/kg) in the range of from 1 :1 to 20:1 , more preferably in the range of from 2:1 to 15:1 , more preferably in the range of from 5:1 to 10:1 , wherein mw is the amount of water comprised in Sw and m? is the amount of polyamide 6 comprised in SM.
  • Preferred ranges are, for example, from 5:1 to 6:1 or from 6:1 to 7:1 or from 7:1 to 8:1 from 8:1 to 9:1 or from 9:1 to 10:1.
  • the melting unit UM according to (ii) comprises a kneader or an extruder, more preferably an extruder, wherein more preferably, the melting unit UM according to (ii) consists of an extruder, wherein more preferably, the extruder is a single-screw extruder or a twin-screw extruder, more preferably a twin-screw extruder.
  • the solid material M which is provided according to (i) and which has a temperature which is lower than TSM is fed into the extruder and melted therein while being conveyed through the extruder.
  • the temperature of solid material which is fed into the extruder has a temperature in the range of from 10 to 50 °C, more preferably in the range of from 15 to 40 °C, more preferably in the range of from 20 to 30 °C.
  • the solid material is fed into the extruder at a pressure in the range of from 0.75 to 5 bar, more preferably in the range of from 0.85 to 3 bar, more preferably in the range of from 0.95 to 1.5 bar.
  • the extruder is preferably equipped with suitable heating means so as to respectively heat up the material M, wherein when leaving the extruder, the liquid stream SM has the temperature TSM.
  • Said suitable heating means can be arranged in a manner so that the extruder exhibits one heating zone or more than one heating zones. It is conceivable that for feeding the solid material M, the extruder has more than one feeding zone. Further according to the present invention, the extruder can be operated either starve-fed or flood-fed.
  • the melting unit UM preferably the extruder
  • the extruder is equipped with a degassing system which serves for removing one or more gases during the melting process in the extruder. While it is generally conceivable that the extruder has more than one degassing zone, it is preferred that it has one degassing zone. Preferably, the degassing zone located directly before the pressure build-up in the extruder discharge zone. If the melting unit UM, preferably the extruder, is equipped with a degassing system, the process preferably comprises removing a gas stream SGM from UM during melting according to (ii).
  • said gas stream SGM has a temperature TGM at a pressure PGM, wherein 0.95 ⁇ TGM/TSM 1.05, preferably 0.95 ⁇ TGM/TSM 1.0.
  • the stream SGM obtained from the melting unit UM is subjected to scrubbing in a scrubbing unit Us, preferably to one or more of wet scrubbing and dry scrubbing, more preferably to wet scrubbing, wherein said wet scrubbing preferably comprises passing the gas stream SGM into a scrubbing column, preferably a packed scrubbing column.
  • the stream SGM obtained from the melting unit UM is preferably subjected to cooling, preferably in a vacuum system via which the stream SGM is preferably removed from the melting unit UM.
  • the stream SM has a pressure PSM wherein said pressure PSM is preferably in the range 0.9 ⁇ PSM/PSF 1 .05 and wherein PSF is in the range 0.9 ⁇ PSF/PD 1 .05.
  • the polyamide 6 depolymerization pressure PD is preferably in the range of from 40 to 140 bar. Therefore, it is preferred according to the present invention that the pressure PSM is higher, more preferably significantly higher than the pressure at which the solid material M is fed into the melting unit UM, preferably into the extruder. According to the present invention, it may be conceivable that this increase in pressure is achieved in the extruder itself.
  • a suitable compression device which is comprised in the melting unit UM, for example a compression device which is arranged downstream of the extruder.
  • the liquid stream leaving the extruder is at essentially the same pressure as the solid material which is fed into the extruder, wherein said liquid stream is then suitably compressed in said compression device to result in the stream SM having the temperature TSM at the pressure PSM.
  • said compression device comprises, more preferably consists of, at least one suitably gear pump, wherein is more than one gear pump is installed, it is preferred that at least two gear pumps are serially arranged.
  • a filtration unit UF is arranged downstream of the melting unit UM and upstream of the reaction unit UR, preferably a filtration unit UF for separating particles having a particle size in the range of from 100 to 500 micrometer, preferably in the range of from 200 to 400 micrometer, from the liquid stream SM, wherein the process comprises passing the stream liquid stream SM through UF, prior to admixing according to (iv).
  • the melting unit UM comprises a compression device as described above, it may be preferred to pass the liquid stream, preferably obtained from the extruder, through said filter device UF before the stream is passed through the compression device.
  • the melting unit UM comprises more than one melting apparatus, preferably more than one extruder, wherein, for example, two or more extruders can be arranged in parallel.
  • TD is in the range of from 230 to 330 °C and PD is in the range of from 40 to 140 bar, more preferably TD is in the range of from 250 to 320 °C and PD is in the range of from 40 to 125 bar, more preferably TD is in the range of from 270 to 310 °C and PD is in the range of from 40 to 110 bar.
  • preferred ranges for TD are, for example, from 270 to 280 °C or 280 to 290 °C or 290 to 300 °C or 300 to 310 °C
  • preferred ranges for PD are, for example, from 40 to 55 bar or from 55 to 70 bar or from 70 to 85 bar or from 85 to 100 bar or from 100 to 110 bar.
  • the reaction unit UR according to (v) comprises at least one reactor in which the liquid stream SF is subjected to depolymerization conditions according to (vi).
  • the reaction unit UR according to (v) comprises 3 reactors Ri, R2 and R3.
  • the z reactors R are vertically arranged, with R1 being the top-most reactor and R z being the bottom-most reactor, wherein Sj obtained from R is transferred to R+i by gravity, preferably by gravity only.
  • the reactors R1, R2 and R3 are vertically arranged, with R1 being the top-most reactor and R3 being the bottom-most reactor, wherein Si obtained from Ri is transferred to R2 by gravity, preferably by gravity only, and wherein S2 obtained from R2 is transferred to R3 by gravity, preferably by gravity only.
  • At least one reactor R is an stirred tank reactor, and more preferably all z reactors are stirred tank reactors.
  • the reactors R1, R2 and R3 are stirred tank reactors.
  • At least one stirred tank reactor R preferably every stirred tank reactor R, has, independently from each other, preferably from 2 to 6 compartments, more preferably from 2 to 5 compartments, more preferably from 2 to 4 compartments, said compartments preferably being serially, more preferably being serially and vertically arranged, wherein 2 adjacent compartments are separated by a divider which comprises at least one flow-through opening.
  • At least one compartment comprised in a reactor R comprises at least one agitator, wherein more preferably, every compartment of every reactor R comprises at least one agitator, wherein more preferably, every compartment of every reactor R comprises one agitator, wherein the process comprises agitating the depolymerization mixture in a given compartment for at least part of the time during subjecting to depolymerization conditions in said compartment.
  • stirred tank reactor R1 has 3 vertically and serially arranged compartments wherein every compartment comprises an agitator
  • the stirred tank reactor R2 has 3 vertically and serially arranged compartments wherein every compartment comprises an agitator
  • the stirred tank reactor R3 has 3 vertically and serially arranged compartments wherein every compartment comprises an agitator.
  • At least one stirred tank reactor R preferably every stirred tank reactor R, has, independently from each other, preferably from 2 to 6 compartments, more preferably from 2 to 5 compartments, more preferably from 2 to 4 compartments, said compartments preferably being serially, more preferably being serially and vertically arranged, wherein said reactor R comprises at least one agitator and wherein 2 adjacent compartments are formed by, and separated by, one or more suitable components of said agitator such as blades comprised in the agitator, wherein the process comprises agitating the depolymerization mixture in a given compartment for at least part of the time during subjecting to depolymerization conditions in the reactor compartment.
  • stirred tank reactor R1 has 2 vertically and serially arranged compartments formed by, and separated by, said suitable components of the agitator comprised in R1
  • the stirred tank reactor R2 has 2 vertically and serially arranged compartments formed by, and separated by, said suitable components of the agitator comprised in R2
  • the stirred tank reactor R3 has 2 vertically and serially arranged compartments formed by, and separated by, said suitable components of the agitator comprised in R 3 .
  • the polyamide 6 depolymerization conditions according to (vi) further comprise a total residence time to of the aqueous depolymerization mixture in the unit UR, preferably in the z reactors R, more preferably in the z stirred tank reactors, wherein at least 85 weight-%, preferably at least 90 weight-%, more preferably at least 95 weight-% of the aqueous depolymerization mixture have a to in the range of from 30 to 90 min.
  • total residence time refers to the sum of the residence times in all chemical reactors R mentioned above.
  • the residence time of an aqueous depolymerization mixture in a reactor R is toi and wherein 0.90 ⁇ (toi I toi+i) 1.10, preferably 0.95 ⁇ (toi I toi+i) 1.05. Therefore, according to the present invention, it is preferred that a narrow residence time distribution is realized.
  • the residence time of the aqueous depolymerization mixture in the reactor R1 is toi
  • the residence time of the aqueous depolymerization mixture in the reactor R2 is tD2
  • the residence time of the aqueous depolymerization mixture in the reactor R3 is tD3
  • At least one of the reactors R preferably all reactors R have one or more outlet means for removing a gas stream from the respective reactor R, i.e. outlet means for degassing the respective reactor R. Therefore, the process of the present invention preferably comprises removing from at least one reactor R, preferably from all z reactors R, a respective gas stream SGI, a given gas stream SGI having a temperature TGI at a pressure PGI, wherein 0.95 ⁇ TGI/TDI 1.05.
  • the process more preferably comprises removing from R1 a gas stream SGI , SGI having a temperature TGI at a pressure PGI , wherein 0.95 ⁇ TGI/TDI 1 .05, removing from R2 a gas stream SG2, SG2 having a temperature TG2 at a pressure PG2, wherein 0.95 ⁇ TG2/TD2 1 .05, and removing from R3 a gas stream SGS, SGS having a temperature TGS at a pressure PGS, wherein 0.95 ⁇ TGS/TDS 1 .05.
  • the process further comprises combining at least one of the gas streams SGI, more preferably all streams SGI, more preferably the gas streams SGI , SG2 and SGS with the gas stream SGM as described hereinabove, preferably prior to subjecting the gas stream SGM to scrubbing as described hereinabove.
  • providing the solid material M according to (i) comprises
  • UMD preferably comprises one or more of at least one big bag station and at least one a bulk container station;
  • the second connecting line preferably comprises one or more of at least one second material feeding unit USMF, at least one second particle separation unit USMPS, and at least one metal detector.
  • the first connecting line according to (i.2) comprises at least one unit UMRD, preferably at least one hopper, more preferably at least one one-zone hopper, and further comprises at least one unit UFMF, preferably at least one rotary feeder, and preferably further comprises at least particle separation unit UFMPS, more preferably at least one filter, more preferably at least one mesh filter.
  • At least one gas stream SG is passed through the first connecting line, said at least one gas stream preferably comprising, more preferably consisting of air or lean air, wherein prior to being passed through the first connecting line, the at least one gas stream is preferably pretreated by at least one of filtrating, compressing and cooling, more preferably by filtrating, compressing and cooling.
  • the second connecting line according to (i.3) comprises at least two units USMF, preferably comprising a rotary feeder and a loss-in-weight feeder, wherein more preferably, the rotary feeder is arranged upstream of the loss-in-weight feeder, and further comprises a unit USMPS, preferably a vibrating screen.
  • the solid material M is provided, preferably provided to UM, in the form of particles, wherein the particle size distribution of said particles is preferably characterized by one or more of the following pairs of values, preferably by two or more of the following pairs of values, more preferably by the following three pairs of values: a D10 value of the particle width in the range of from in the range of from 0.3 to 15 mm and a D10 value of the particle length in the range of from 0.3 to 15 mm; a D50 value of the particle width in the range of from in the range of from 0.5 to 20 mm and a D50 value of the particle length in the range of from 0.5 to 20 mm; a D90 value of the particle width in the range of from in the range of from 0.8 to 30 mm and a D90 value of the particle length in the range of from 0.8 to 30 mm.
  • More preferred pairs of values are, for example: a D10 value of the particle width in the range of from in the range of from 2 to 4 mm and a D10 value of the particle length in the range of from 3.5 to 5.5 mm; a D50 value of the particle width in the range of from in the range of from 2.5 to 4.5 mm and a D50 value of the particle length in the range of from 4 to 7 mm; a D90 value of the particle width in the range of from in the range of from 3 to 5 mm and a D90 value of the particle length in the range of from 4.5 to 8.5 mm.
  • particle as used in this context of the present invention comprises optionally preformed granules, and also comprises shredded pieces.
  • the solid material M provided according to (i) consist of the polyamide 6. If the polyamide 6 content of the solid material M is less than 100 weight-%, it may be preferred that the solid material M additionally comprises one or more elastanes.
  • the solid material M may comprise, in addition to polyamide 6, at least one further polymeric compound, wherein the at least one further polymeric compound preferably comprises one or more of at least one polyamide 6.6; at least one semiaromatic polyamide including one or more of polyamide 6T and polyamide 6I; at least one polyethylene terephthalate; at least one polyurethane; at least one polyester; at least one polyether; at least one polyvinyl chloride; at least one natural fiber material such as wool and cotton; at least one cellulose material; at least one natural elastomer; at least one synthetic elastomer; at least one copolymer of two or more of said polymeric compounds including statistical copolymers, gradient copolymers, alternating copolymers, block copolymers, and graft copolymers; and at least one rubber material comprising one or more of at least one natural rubber material and at least one synthetic rubber material.
  • the solid material M may further comprise one or more of at least one pigment material and at
  • the solid material M provided according to (i) comprises, more preferably consists of, a waste material, more preferably one or more of a textile waste material and an engineering plastics waste material, more preferably a textile waste material.
  • at least one of the chemical materials Mj more preferably every chemical material Mj comprises, preferably consists of a waste material, said waste material preferably comprising, more preferably consisting of at least one textile waste material. If w>1 , the respective two or more materials may have different chemical compositions which are not subject to any specific restrictions with the proviso that the solid material M exhibits the composition as discussed above.
  • the present invention it is preferred that from 90 to 100 weight-%, more preferably from 91 to 100 weight-%, more preferably from 92 to 100 weight-%, more preferably from 93 to 100 weight-%, more preferably from 94 to 100 weight-%, more preferably from 95 to 100 weight- % of the liquid aqueous stream Sw provided according to (iii) consist of water. More preferred ranges may be from 96 to 100 weight-% or from 97 to 100 weight-% or from 99 to 100 weight-% or from 99 to 100 weight-%.
  • providing the liquid aqueous stream Sw according to (iii) comprises generating an aqueous stream comprising at least part of the water comprised in the stream SR, and feeding at least part of said generated aqueous stream back to the chemical reaction unit UR as the aqueous stream Sw or as part thereof.
  • the process comprises subjecting the stream SR obtained from the chemical reaction unit UR, optionally after subjecting SR to filtration, to thermal water separation, obtaining an aqueous stream Sx; and feeding at least part of the aqueous stream Sx back to the chemical reaction unit UR as part of the aqueous stream Sw, wherein said thermal water separation preferably comprises one or more of distilling and falling film evaporating.
  • generating the aqueous stream Sx may comprise distilling the stream SR obtained from the reaction unit UR, optionally after subjecting SR to filtration, obtaining the stream Sx.
  • Said distilling preferably may be carried out in a distillation column at a bottoms temperature preferably in the range of from 70 to 140 °C, more preferably in the range of from 80 to 120 °C, more preferably in the range of from 90 to 110 °C, and a top pressure preferably in the range of from 0.5 to 1.5 bar, more preferably in the range of from 0.7 to 1.2 bar, more preferably in the range of from 0.8 to 1 .1 bar, wherein the stream Sx is obtained at the top of the distillation column.
  • said distilling preferably may comprise subjecting the vapor top stream to condensation, obtaining a liquid stream Sx, wherein at least a part of the liquid stream Sx is fed back to the chemical reaction unit UR as part of the aqueous stream Sw.
  • Said liquid stream Sx obtained from condensation may preferably be divided into 2 streams, wherein a first stream obtained from dividing is fed back to the chemical reaction unit UR as part of the aqueous stream Sw and a second stream is fed back to the top of the distillation column, wherein the volume ratio of the first stream relative to the second stream is preferably in the range of from 10:1 to 0.5:1 , more preferably in the range of from 7:1 to 1 :1 , more preferably in the range of from 5:1 to 2:1.
  • (x) recycling at least one stream Svw at least partially to the reaction unit UR and at least one stream SRW at least partially to the reaction unit UR.
  • the recycling according to (x) preferably comprises
  • the purification unit UP preferably comprises one or more of a heat-consuming water separation unit Uws, a heat-consuming distillation unit UD and a heat-consuming crystallization unit Uc, more preferably two or more of a heat-consuming water separation unit Uws, a heat-consuming distillation unit UD and a heat-consuming crystallization unit Uc, more preferably a heatconsuming water separation unit Uws, a heat-consuming distillation unit UD and a heat-consuming crystallization unit Uc, wherein at least part of the heat consumed in one or more of Uws, UD and Uc is provided by at least one of the one or more streams Sv.
  • the process preferably comprises one or more of (a-1 ), (a-2) and (a- 3); more preferably at least two or more of (a-1 ), (a-2) and (a-3); more preferably (a-1 ), (a-2) and (a-3):
  • (a-3) obtaining at least one at least partially condensed aqueous stream Svws from Uc; wherein the process further comprises feeding one or more Svwi, Svw2 and Svws; preferably two or more Svwi, Svw2 and Svws; more preferably Svwi, Svw2 and Svws into the water treatment unit Uw as defined in embodiment 29.
  • the purification unit UP comprises a heat-consuming water separation unit Uws, a heat-consuming distillation unit UD and a heat-consuming crystallization unit Uc, wherein the process comprises feeding the stream SL comprising e-caprolactam at a concentration CSL to Uws, obtaining from Uws a stream Uws comprising e-caprolactam at a concentration Cuws, feeding the stream Sows to the distillation unit UD, obtaining from UD a stream SUD comprising e-caprolactam at a concentration CUD, and feeding the stream SUD into the crystallization unit Uc, and obtaining from Uc a stream SCPL comprising e-caprolactam at a concentration CSCPL, wherein CSL ⁇ Cuws ⁇ CUD ⁇ CSCPL-
  • the water separation unit Uws comprises at least two heat-consuming water separation sub-units Uwsi and Uws2, more preferably two serially coupled heat-consuming water separation sub-unit
  • the process preferably comprises one or more of (b-1 ) and (b-2) preferably (b-1 ) and (b-2):
  • At least one aqueous stream SRWI is obtained from Uwsi and at least one aqueous stream SRW2 is obtained from Uws2, and wherein at least one of SRWI and SRW2, preferably SRWI and SRW2 are fed into Uw.
  • a separation unit Ui downstream of Uwsi and upstream of Uws2, a separation unit Ui is located, wherein the process preferably comprises obtaining from Uwsi an aqueous stream Suwsi, feeding the stream Suwsi into the separation unit Ui, obtaining from Ui an aqueous stream Sui, and feeding the stream Sui into the unit Uws2, wherein in Ui, one or more of impurities are separated from Suwsi, thereby obtaining from Ui an impurity stream Si, said impurities preferably comprising at least one impurity comprised in SR according to (vii).
  • the evaporation unit UE comprises two or more evaporation sub-units, wherein the process preferably comprises obtaining at least two vapor streams Svi and Sv2, passing the vapor stream Svi to at least one heat-consuming unit and passing the vapor stream Sv2 to at least one heat-consuming unit, wherein the vapor streams Svi and Sv2 differ from each other in either pressure and/or temperature.
  • At least one solid-liquid separation unit is arranged downstream of UR, wherein it is preferred that at least one of the streams SL and SR is passed through at least one solid-liquid separation unit prior to being passed to the next downstream unit.
  • the solid material M provided according to (i) comprises, preferably consists of, a waste material, preferably one or more of a textile waste material and an engineering plastics waste material, more preferably of a textile waste material.
  • the stream SCPL described above i.e. the purified s-caprolactam stream
  • said stream SCPL is passed to a polyamide 6 production unit UPP where it is employed as starting material.
  • one or more further streams SNCPL can be additionally passed to UPP, said streams comprising non-recycled s-caprolactam, i.e. s-caprolactam from a conventional source.
  • the respectively prepared polyamide 6 material preferably may then be passed to a unit UTP where it is used as a starting material for preparing a material comprising polyamide 6, preferably a textile material comprising polyamide 6.
  • one or more further streams SNPAS can be additionally passed to UTP, said streams comprising non-recycled polyamide 6, i.e. polyamide 6 from a conventional source.
  • further streams comprising one or more starting materials other than polyamide 6 can be passed to UTP.
  • the material, preferably the textile material MT obtained from UTP then preferably goes into the market and remains there for a given lifetime TMT.
  • the respective end-of-life material is suitably collected in a collecting unit UTC, preferably a textile material collecting unit, from which it is suitably passed as the solid material M or as part of the solid material M to the process as described above, optionally after sorting as described herein.
  • the process may preferably further comprise providing the stream SCPL to a polyamide 6 production unit UPP, wherein the polyamide 6 produced in UPP is preferably provided as a feedstock to a textile material producing unit UTP, from which unit UTP
  • a textile material MT is obtained which is brought onto the market, wherein, after the lifetime TMT of said textile material MT, it is at least partially collected as textile waste material in a textile material collecting unit UTC ;
  • (B) remaining material MR is obtained as textile waste material; wherein at least part of the textile waste material according to (A), or at least part of the textile waste material according to (B), or at least part of the textile waste material according to (A) and at least part of the textile waste material according to (B) is suitably provided to UR via UM.
  • the present invention also relates to the use of SCPL, obtainable or obtained by a process as described hereinabove, for preparing polyamide 6, said use preferably further comprising employing said polyamide 6 as a feedstock for preparing a textile material.
  • the present invention also relates to a method for preparing polyamide 6, said method comprising employing SCPL, obtainable or obtained by a process as described hereinabove, as a starting material, wherein said method preferably further comprises employing said polyamide 6 as a feedstock for preparing a textile material.
  • the process may preferably further comprise providing the stream SCPL to a polyamide 6 production unit UPP, wherein the polyamide 6 produced in UPP is preferably provided as a feedstock to an engineering plastics material producing unit UEP, from which unit UEP
  • an engineering plastics material ME is obtained which is brought onto the market, wherein, after the life-time TME of said engineering plastics material ME it is at least partially collected as engineering plastics waste material in an engineering plastics material collecting unit UEC;
  • (B) remaining material MR is obtained as engineering plastics waste material; wherein at least part of the engineering plastics waste material according to (A), or at least part of the engineering plastics waste material according to (B), or at least part of the engineering plastics waste material according to (A) and at least part of the engineering plastics waste material according to (B) is suitably provided to UR as SM, preferably via UM.
  • the present invention also relates to the use of SCPL, obtainable or obtained by a process as described hereinabove, for preparing polyamide 6, said use preferably further comprising employing said polyamide 6 as a feedstock for preparing an engineering plastics material.
  • the present invention also relates to a method for preparing polyamide 6, said method comprising employing SCPL, obtainable or obtained by a process as described hereinabove, as a starting material, wherein said method preferably further comprises employing said polyamide 6 as a feedstock for preparing an engineering plastics material.
  • the present invention relates to an integrated process for preparing polyamide 6, comprising
  • the optionally concentrated stream comprising water and one or more £-caprolactam oligomers according to (E) further comprises £-caprolactam, i.e. monomeric £-caprolactam.
  • said integrated process comprises
  • the stream SEW which is obtained from the polyamide 6 polymerization unit UPA comprises water, monomeric £-caprolactam and one or more £-caprolactam oligomers.
  • this aqueous stream SE furher comprises one or more further organic compounds other than monomeric £-caprolactam and one or more £-caprolactam oligomers. Therefore, it is preferred that the stream SEW further comprises one or more organic compounds X other than £-caprolactam and oligomers thereof at a total concentration CEW(X), the process according to (5) comprising
  • (y) comprises
  • the process may preferably further comprise passing at least some of said material MPR to the unit UM.
  • the process of the present invention as described above may preferably be a continuous process. However, one or more process steps may be carried out in a batch-type mode, and one or more steps may be carried out in a semicontinuous mode.
  • a process for hydrolytically depolymerizing a polyamide 6 comprised in a solid material M the process comprising
  • the melting unit UM comprises, preferably consists of an extruder, preferably a single-screw extruder or a twin-screw extruder.
  • a filtration unit UF is arranged, preferably a filtration unit UF for separating particles having a particle size in the range of from 100 to 500 micrometer, preferably in the range of from 200 to 400 micrometer, from the liquid stream SM, wherein the process comprises passing the stream liquid stream SM through UF, prior to admixing according to (iv).
  • TD is in the range of from 230 to 330 °C and PD is in the range of from 40 to 140 bar, preferably wherein TD is in the range of from 250 to 320 °C and PD is in the range of from 40 to 125 bar, more preferably wherein TD is in the range of from 270 to 310 °C and PD is in the range of from 40 to 110 bar.
  • every stirred tank reactor R has, independently from each other, from 2 to 6 compartments, preferably from 2 to 5 compartments, more preferably from 2 to 4 compartments, said compartments preferably being serially, more preferably being serially and vertically arranged, wherein 2 adjacent compartments are separated by a divider which comprises at least one flow-through opening.
  • At least one compartment comprised in a reactor R comprises at least one agitator, wherein preferably every compartment of every reactor R comprises at least one agitator, wherein more preferably, every compartment of every reactor R comprises one agitator, wherein the process comprises agitating the depolymerization mixture in a given compartment for at least part of the time during subjecting to depolymerization conditions in said compartment.
  • invention 17 as far as embodiment 17 is dependent on any one of embodiments 11 to 16 with z > 1 , preferably on embodiment 15 or 16 with z > 1 , wherein the residence time of an aqueous depolymerization mixture in a reactor Rj is toi and wherein 0.90 ⁇ (toi I toi+i) 1.10, preferably 0.95 ⁇ (toi I toi+i) 1.05.
  • the process of any one of embodiments 11 to 18, comprising removing from at least one reactor R, preferably from all z reactors R, a respective gas stream SGI, a given gas stream SGI having a temperature TGI at a pressure PGI, wherein 0.95 ⁇ TGI/TDI 1.05.
  • UMD preferably comprises one or more of at least one big bag station and at least one a bulk container station;
  • the second connecting line preferably comprises one or more of at least one second material feeding unit USMF, at least one second particle separation unit USMPS, and at least one metal detector.
  • the first connecting line according to (i.2) comprises at least one unit UMRD, preferably at least one hopper, more preferably at least one one-zone hopper, and further comprises at least one unit UFMF, preferably at least one rotary feeder, and preferably further comprises at least particle separation unit UFMPS, more preferably at least one filter, more preferably at least one mesh filter.
  • the second connecting line according to (i.3) comprises at least two units USMF, preferably comprising a rotary feeder and a loss-in-weight feeder, wherein more preferably, the rotary feeder is arranged upstream of the loss-in-weight feeder, and further comprises a unit USMPS, preferably a vibrating screen.
  • the solid material M is provided, preferably provided to UM, in the form of granules, wherein the particle size distribution of said granules is preferably characterized by one or more of the following pairs of values, preferably by two or more of the following pairs of values, more preferably by the following three pairs of values: a D10 value of the particle width in the range of from in the range of from 0.3 to 15 mm and a D10 value of the particle length in the range of from 0.3 to 15 mm; a D50 value of the particle width in the range of from in the range of from 0.5 to 20 mm and a D50 value of the particle length in the range of from 0.5 to 20 mm; a D90 value of the particle width in the range of from in the range of from 0.8 to 30 mm and a D90 value of the particle length in the range of from 0.8 to 30 mm.
  • the purification unit UP comprises one or more of a heat-consuming water separation unit Uws, a heat-consuming distillation unit UD and a heat-consuming crystallization unit Uc, preferably two or more of a heat-consuming water separation unit Uws, a heat-consuming distillation unit UD and a heatconsuming crystallization unit Uc, more preferably a heat-consuming water separation unit Uws, a heat-consuming distillation unit UD and a heat-consuming crystallization unit Uc, wherein at least part of the heat consumed in one or more of Uws, UD and Uc is provided by at least one of the one or more streams Sv.
  • (i-3) obtaining at least one at least partially condensed aqueous stream Svws from Uc; the process further comprising feeding one or more Svwi, Svw2 and Svws; preferably two or more Svwi, Svw2 and Svws; more preferably Svwi, Svw2 and Svws into the water treatment unit Uw as defined in embodiment 29.
  • the purification unit UP comprises a heat-consuming water separation unit Uws, a heat-consuming distillation unit UD and a heat-consuming crystallization unit Uc, the process comprising feeding the stream SL comprising e-caprolactam at a concentration CSL to Uws, obtaining from Uws a stream Uws comprising e-caprolactam at a concentration Cuws, feeding the stream Sows to the distillation unit UD, obtaining from UD a stream SUD comprising e-caprolactam at a concentration CUD, and feeding the stream SUD into the crystallization unit Uc, and obtaining from Uc a stream SCPL comprising e-caprolactam at a concentration CSCPL, wherein
  • the water separation unit Uws comprises at least two heat-consuming water separation sub-units Uwsi and Uws2, preferably two serially coupled heat-consuming water separation sub-units Uwsi and Uws2, wherein the stream SL is fed into Uwsi and wherein at least part of the heat consumed in one or more of Uwsi and Uws2 is provided by at least one of the one or more streams Sv.
  • a textile material MT is obtained which is brought onto the market, wherein, after the life-time TMT of said textile material MT, it is at least partially collected as textile waste material in a textile material collecting unit UTC ;
  • (B) remaining material MR is obtained as textile waste material; wherein at least part of the textile waste material according to (A), or at least part of the textile waste material according to (B), or at least part of the textile waste material according to (A) and at least part of the textile waste material according to (B) is suitably provided to UR via UM.
  • the process of any one of embodiments 1 to 41 wherein from 90 to 100 weight-%, preferably from 91 to 100 weight-%, more preferably from 92 to 100 weight-%, more preferably from 93 to 100 weight-%, more preferably from 94 to 100 weight-%, more preferably from 95 to 100 weight-% of the liquid aqueous stream Sw provided according to (iii) consist of water.
  • any one of embodiments 1 to 42 being a continuous process, a semicontinuous process or a batch process.
  • the process of any one of embodiments 1 to 43, wherein the solid material M provided according to (i) comprises, preferably consists of, a waste material, preferably one or more of a textile waste material and an engineering plastics waste material, more preferably of a textile waste material.
  • SCPL obtainable or obtained by a process according to any one of embodiments 28 to 44, for preparing polyamide 6, said use preferably further comprising employing said polyamide 6 as a feedstock for preparing one or more of a textile material and an engineering plastics material, more preferably for preparing a textile material.
  • SCPL obtainable or obtained by a process according to any one of embodiments 28 to 44, for preparing one or more of a polymer and a polymer product; or a method for preparing one or more of a polymer and a polymer product, said method comprising employing SCPL, obtainable or obtained by a process according to any one of embodiments 28 to 44, as a starting material.
  • polymer, or the polymer product, or the polymer and the polymer product is or are in the form of at least one of a granulate, a strand, a rod, a plate, a pipe, a foil, a layer, a film, a sheet, a fiber, a filament, a coating, an extruded article, a molded article, a soft foam, a half-rigid foam and a rigid foam.
  • polymer, or the polymer product, or the polymer and the polymer product comprises or comprise polyamide 6 and optionally at least one further polymeric compound, wherein the at least one further polymeric compound preferably comprises one or more of at least one polyamide 6.6; at least one semiaromatic polyamide including one or more of polyamide 6T and polyamide 61; at least one polyethylene terephthalate; at least one polyurethane; at least one polyester; at least one polyether; at least one polyvinyl chloride; at least one natural fiber material such as wool and cotton; at least one cellulose material; at least one natural elastomer; at least one synthetic elastomer; at least one copolymer of two or more of said polymeric compounds including statistical copolymers, gradient copolymers, alternating copolymers, block copolymers, and graft copolymers; and at least one rubber material comprising one or more of at least one natural rubber material and at least one synthetic rubber material
  • any one of embodiments 47 to 50 wherein the polymer, or the polymer product, or the polymer and the polymer product contains or contain polyamide 6 in an amount of 1 weight-% or more, preferably 2 weight-% or more, more preferably 5 weight-% or more, more preferably 15 weight-% or more, more preferably 30 weight-% or more, more preferably 40 weight-% or more, more preferably 60 weight-% or more, more preferably 80 weight-% or more, more preferably 90 weight-% or more, more preferably 95 weight-% or more; and/or in an amount of 100 weight-% or less, preferably 95 weight-% or less, more preferably 90 weight-% or less, more preferably 50 weight-% or less, more preferably 25 weight-% or less, more preferably 10 weight-% or less.
  • polyamide 6 in an amount of 1 weight-% or more, preferably 2 weight-% or more, more preferably 5 weight-% or more, more preferably 15 weight-% or more, more preferably 30 weight-% or more, more
  • the respective amounts are preferably determined based on identity preservation and/or segregation and/or mass balance and/or book and claim chain of custody models, more preferably based on mass balance, more preferably the International Sustainability and Carbon Certification (ISCC) standard.
  • ISCC International Sustainability and Carbon Certification
  • preparing the polymer, the polymer product, or the polymer and the polymer product may comprise one or more synthesis steps and can be performed by conventional synthesis and technics well known to the person skilled in the art. Examples of the synthesis steps are described in “Industrial Organic Chemistry”, 3 rd volume, Wiley-VCH, 1997; ISBN: 978-3-527-28838-0; complicatKunststoffhandbuch”, 11 volumes in 17 subvolumes, Carl HanserVerlag, especially volume 6, arrangement 6, arrangement 6, arrangement 6, arrangement 6, arrangement 6, arrangement”, 1 st edition, 1966; “Injection Molding Reference Guide, 4 th edition, CreateSpace Independent Publishing Platform, 2011 , ISBN: 978-1466407824; WO 2008/155271 A1 and WO 2013/139827 A1 , each of which is incorporated herein by reference.
  • the term crizbar“ as used herein refers to scatteredbar(abs)”, i.e. bar (absolute), sometimes also referred to “bara”.
  • textile material covers textile raw materials and non-textile raw materials that are processed by various methods into linear, planar and spatial structures. It concerns the linear textile structures produced from them, such as yarns, twisted yarns and ropes, the sheet-like textile structures, such as woven fabrics, knitted fabrics, braids, stitch- bonded fabrics, nonwovens and felts, and the three-dimensional textile structures, i.e. body structures, such as textile hoses, stockings or textile semi-finished products; and it further concerns those finished products which, using the aforementioned products, are brought into a saleable condition by making up, opening up and/or other operations for onward transmission to the processor, the trade or the end consumer.
  • textile waste material covers a textile material as defined above, the inherent value of which has been consumed from the perspective of its current holder and, thus, is an end-of-life material for said holder.
  • engineering plastics refers to high-performance plastics grades which possess physical properties enabling them to perform for prolonged use in structural applications, over a wide temperature range, under mechanical stress, and in difficult chemical and physical environments used for example to fabricate plastic parts replacing traditional engineering materials like metals and ceramics.
  • Engineering plastics specifically apply in the fabrication of mechanical parts across several industries such as automotive, medical, electrical and electronics, aerospace, construction and consumer products.
  • engineering plastics waste material covers an engineering plastics material as defined above, the inherent value of which has been consumed from the perspective of its current holder and, thus, is an end-of-life material for said holder.
  • spandex is also referred to as “spandex”, and common brand names for spandex include Lycra, Elaspan, Acepora, Creora, Inviya, Roica, Dorlastan, Linel or ESPA.
  • X is a chemical element and A, B and C are concrete elements such as Li, Na, and K, or X is a temperature and A, B and C are concrete temperatures such as 10 °C, 20 °C, and 30 °C.
  • X is one or more of A and B” disclosing that X is either A, or B, or A and B, or to more specific realizations of said feature, e.g. ‘ is one or more of A, B, C and D”, disclosing that X is either A, or B, or C, or D, or A and B, or A and C, or A and D, or B and C, or B and D, or C and D, or A and B and C, or A and B and D, or B and C and D, or A and B and C and D, or A and B and C and D, or A and B and C and D, or A and B and C and D, or A and B and C and D.
  • Preferred aspects of the present invention are further illustrated in the Figures 1 to 14 as described hereinunder.
  • Fig. 1 illustrates a process according to the present invention.
  • a suitably provided solid material M comprising polyamide 6 is fed into a melting unit UM from which a liquid stream SM is obtained and further passed to a pre-reaction unit UPR where it is admixed with a liquid aqueous stream Sw.
  • a liquid stream SF which is obtained from the unit UPR is then passed to a reaction unit UR where it is subjected to polyamide 6 depolymerization conditions to obtain an aqueous depolymerization mixture which comprises e-caprolactam dissolved in water.
  • an aqueous liquid reactor exit stream SR comprising e-caprolactam dissolved in water then removed.
  • Fig. 2 illustrates a process according to the present invention.
  • the melting unit UM according to Fig. 2 is equipped with a degassing system. Via this degassing system, a gas stream SGM is removed which is obtained when the solid material M is melted in UM. The stream SGM is then passed to a scrubbing unit Us.
  • Fig. 3 illustrates a process according to the present invention.
  • a filtration unit UF is arranged downstream of the melting unit UM and upstream of the reaction unit UR.
  • the stream SM which is obtained from the unit UM is passed through this filtration unit and, downstream of UF, is passed as suitably filtrated stream SM to the pre-reaction unit UPR.
  • Fig. 4 illustrates a process according to the present invention.
  • the unit UR consists of three reactors Ri, R2 and R3 which are arranged in series and which are preferably vertically arranged.
  • the stream SSF which is obtained from the pre-reaction unit UPR is fed into the reactor R1 where it is subjected to polyamide 6 depolymerization conditions, and from which a liquid aqueous stream Si is obtained which comprises e-caprolactam dissolved in water and further comprises non-depolymerized polyamide 6.
  • the stream Si is then passed, preferably by gravity only, to the reactor R2 where it is subjected to polyamide 6 depolymerization conditions, and from which a liquid aqueous stream S2 is obtained which comprises e-caprolactam dissolved in water und further comprises non-depolymerized polyamide 6.
  • the stream S2 is then passed, preferably by gravity only, to the reactor R3 where it is subjected to polyamide 6 depolymerization conditions, and from which a liquid aqueous stream S3 is obtained which comprises e-caprolactam dissolved in water.
  • This stream S3 is then removed as the stream SR from the reaction unit UR.
  • Fig. 6 illustrates a process according to the present invention. Compared to the process design shown in Fig. 4, a preferred design is shown how the solid material M is provided.
  • the solid material is provided in a delivering unit MMD which, for example, may comprise one or more big bag stations and/or one or more bulk container stations.
  • the material is then passed to a suitably material collecting unit MMC which preferably comprises, more preferably consists of a drum.
  • the material is then suitably passed to the melting unit UM.
  • Fig. 7 illustrates a process according to the present invention. Compared to the process design shown in Fig. 6, a preferred process is shown how the solid material is passed from the delivering unit UMD to the collecting unit UMC via a first connecting line.
  • the unit UMD according to Fig. 7 comprises, for example, one bulk container station from which material M is passed to a particle separation unit UFMPS(1 ), and two big bag stations, wherein from the first big bag station, material M is passed to a particle separation unit UFMPS(2.1 ) and wherein from the second big bag station, material M is passed to a particle separation unit UFMPS(2.2).
  • material M is then passed through a feeding unit UFMF(1 ), such as a rotary feeder, and via UFMF(1 ), it is passed and optionally distributed to the receiving and discharge means UMRD(3), preferably a hopper, and UMRD(4), preferably a hopper.
  • material M is then passed to a receiving and discharge means UMRD(2.1 ), preferably a hopper, and from UMRD(2.1 ) through a feeding unit UFMF(2.1 ), such as a rotary feeder, and via UFMF(2.1 ), it is passed and optionally distributed to the receiving and discharge means UMRD(3) and UMRD(4).
  • material M is then passed to a receiving and discharge means UMRD(2.2), preferably a hopper, and from UMRD(2.2) through a feeding unit UFMF(2.2), such as a rotary feeder, and via UFMF(2.2), it is passed and optionally distributed to the receiving and discharge means UMRD(3) and UMRD(4).
  • a receiving and discharge means UMRD(2.2) preferably a hopper
  • UMRD(2.2) through a feeding unit UFMF(2.2), such as a rotary feeder, and via UFMF(2.2)
  • material M is then passed to the collecting unit UMC via either the unit UFMF(3), preferably a rotary feeder, and/or the unit UFMF(4), preferably a rotary feeder.
  • gas streams SG(1 ), SG(2) and SG(3) are shown which are passed into the respective sections of the first connecting line to (pneumatically) transport material M to the respective downstream units as shown. At least one of said gas streams, preferably all gas streams are preferably subject to gas filtration, followed by compression and subsequent cooling, prior to being passed into the respective sections of the first connecting line (not shown).
  • Fig. 8 illustrates a process according to the present invention.
  • the solid material M is passed from the collecting unit UMC, preferably comprising a collecting drum, to the melting unit UM via a second connecting line.
  • the solid material M is passed from the unit UMC through a first feeding unit USMF(1 ), such as a rotary feeder, to a particle separation unit USMPS such as a vibrating screen.
  • USMF(1 ) such as a rotary feeder
  • USMPS particle separation unit
  • material M is then passed to a second feeding unit USMF(2), preferably a loss-in weight feeding means such as a loss-in-weight screw from which the material M is then suitably passed to the melting unit UM.
  • the preferred process upstream of the unit UM as shown in Fig. 8 is to be seen in connection with the preferred process as shown in Fig. 6.
  • Fig. 9 illustrates a process according to the present invention.
  • a gas stream SGI is obtained in and removed from each reactor Rj comprised in the unit UR.
  • These gas streams, specifically SGI , SG2 and SGS are then suitably combined and passed to a scrubber unit Us.
  • the streams SGI may also be passed to the unit Us separately (alternative not shown). It is further conceivable that one or more of the streams SGI are combined, prior to being fed into Us, with the gas stream SGM obtained from the melting unit UM (alternative not shown).
  • Fig. 10 illustrates a process according to the present invention.
  • a liquid aqueous stream S3 is obtained and removed as the stream SR from the last reactor R3 of the unit UR which comprises c- caprolactam and one or more impurities.
  • This stream SR is then passed to an evaporation unit UE from which a liquid aqueous stream SL and one or more aqueous vapor streams Sv are obtained and removed; in Fig. 10, only one vapor stream Sv is shown.
  • the stream SL has a higher c- caprolactam concentration than the stream SR.
  • the stream SL is then passed to a heatconsuming purification unit UP where a further purification with regard to c-caprolactam occurs.
  • a product stream SCPL is finally obtained which comprises c-caprolactam at a concentration which is significantly higher than the c-caprolactam concentration of the stream SL.
  • at least a part of the heat consumed in the purification unit UP is at least partially provided by at least one of the one or more vapor streams Sv and based on Sv, one or more at last partially condensed aqueous streams Svw are obtained and removed from UP; only one stream Svw is shown in Fig. 10.
  • one or more aqueous streams SRW are obtained from SL. At least one stream Svw is then at least partially recycled to the reaction unit UR, and also at least one stream SRW is at least partially recycled to the reaction unit UR wherein, for said recycling purposes, the streams Svw and SRW are passed into a water treatment unit Uw from which a stream Sw is obtained which is then (at least partially) recycled as aqueous stream Sw (or part thereof) to the reaction unit UR. Further from Uw, one or more waste water streams Sww are obtained which are not recycled to the process.
  • the water treatment unit Uw comprises a water recovery unit UWR and optionally a waste water unit Uww.
  • the streams Svw and SRW are passed into the water treatment unit Uw where they are suitably purified and/or suitably collected in order to obtain the one or more aqueous recycle streams. Streams which are obtained from such purification may then be passed to the waste water treatment unit Uww from which a waste water stream Sww is obtained.
  • Fig. 11 illustrates a process according to the present invention.
  • the process according to Fig. 11 shows the further use of the stream SCPL, i.e. the purified s-caprolactam.
  • stream SCPL is preferably passed to a polyamide 6 production unit UPP where it is employed as starting material.
  • one or more further streams SNCPL can be additionally passed to UPP, said streams comprising non-recycled s-caprolactam, i.e. s-caprolactam from a conventional source.
  • the respectively prepared polyamide 6 material is then passed to a unit UTP where it is used as a starting material for preparing a material comprising polyamide 6, preferably a textile material comprising polyamide 6.
  • one or more further streams SNPAS can be additionally passed to UTP, said streams comprising non-recycled polyamide 6, i.e. polyamide 6 from a conventional source.
  • further streams comprising one or more starting materials other than polyamide 6 can be passed to UTP.
  • the material, preferably the textile material MT obtained from UTP then goes into the market and remains there for a given lifetime TMT.
  • the respective end-of-life material is suitably collected in a collecting unit UTC, preferably a textile material collecting unit, from which it is suitably passed as stream the SM or as part of the stream SM to the reaction unit UR preferably via a unit UM for providing the stream SM to UR.
  • Such unit UM usually comprises any apparatus by which the preferably solid material M can be suitably passed to the reaction unit UR.
  • UM comprises apparatuses such as one or more silos, one or more hoppers, one or more truck unloading stations, one or more big bag unloading station, and the like.
  • Fig. 11 it is shown that in the production unit UTP, remaining material MR is obtained from the production process, i.e. material which is not comprised in MT.
  • MR may be in the form of textile cuttings. This material can be fed, either via UTC and/or directly via UM, to UR as the stream SM or as part of stream SM, preferably according to processes illustrated in Figs. 6, 7 and 8 hereinabove.
  • Fig. 12 illustrates a process according to the present invention.
  • a preferred design of the unit UP is shown, i.e. the process as shown in Fig. 12 shows a preferred way of purifying the stream SL with respect to e-caprolactam.
  • the stream SL is first passed to a water separation unit Uws from which the one or more streams SRW are obtained which are then preferably passed to the water treatment unit Uw as already shown in Fig. 11 .
  • At least one of the streams Sv is passed to Uws for at least partially meeting the heat demand of Uws; based on this at least one stream Sv passed to Uws, one or more at least partially condensed streams Svwi are obtained and preferably further passed to the water treatment unit Uw, specifically UWR.
  • the stream Sows comprising e-caprolactam is then preferably passed to a distillation unit UD for further purification with respect to e-caprolactam.
  • At least one of the streams Sv is passed to UD for at least partially meeting the heat demand of UD; based on this at least one stream Sv passed to UD, one or more at least partially condensed streams Svw2 are obtained and preferably further passed to the water treatment unit Uw, specifically UWR.
  • the stream SUD comprising e-caprolactam is then preferably passed to a crystallization unit Uc for further purification with respect to e-caprolactam.
  • at least one of the streams Sv is passed to Uc for at least partially meeting the heat demand of Uc; based on this at least one stream Sv passed to Uc, one or more at least partially condensed streams Svws are obtained and preferably further passed to the water treatment unit Uw, specifically UWR.
  • Fig. 13 illustrates a process according to the present invention.
  • a preferred design of the unit Uws is shown, i.e. the process as shown in Fig. 13 shows a preferred way of separating water from the stream SL.
  • the stream SL is first passed to a first stage of water separation, carried out in the unit Uwsi.
  • a stream Suwsi comprising e-caprolactam is then passed to an intermediate treatment stage Ui where impurities may be removed.
  • the thus purified stream Sui obtained from Ui is then further passed to a second stage of water separation, carried out in the unit Uws2.
  • a stream Suws2 comprising e-caprolactam is obtained which corresponds to the stream Sows as shown in Fig. 12 and which is then preferably passed to the distillation unit UD.
  • a stream Si comprising the respectively separated impurities is removed which, depending on the amount and/or the chemical nature of the impurities, may be put to further use.
  • one or more aqueous streams SRWI are obtained which are then preferably passed to the water treatment unit Uw, specifically UWR.
  • one or more aqueous streams SRW2 are obtained which are then preferably passed to the water treatment unit Uw, specifically UWR.
  • Fig. 14 illustrates a process according to the present invention. Compared to Fig. 13, the preferred recycling loop as already shown in Fig. 11 hereinabove is additionally shown, as well as the treatment of the gas streams S Gi obtained in and removed from the reactors Ri, R2 and R3, as already shown in Fig. 9 hereinabove.

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  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
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  • Polyamides (AREA)

Abstract

L'invention concerne un procédé de dépolymérisation hydrolytique d'un polyamide 6 contenu dans un matériau solide M, le procédé comprenant la fourniture du matériau solide M ; la fusion dans une unité de fusion UM du matériau solide M, l'obtention d'un flux liquide SM ayant une température TSM à une pression pSM ; la fourniture d'un flux aqueux liquide SW ayant une température TSW à une pression pSW ; le mélange dans une unité de pré-réaction UPR du flux SM avec le flux SW, l'obtention d'un flux d'alimentation de réaction liquide SF ayant une température TSF à une pression pSF ; l'introduction du flux SF dans une unité de réaction chimique UR ; la soumission du flux SF dans l'unité de réaction UR à des conditions de dépolymérisation de polyamide 6 comprenant une température de dépolymérisation de polyamide 6 TD à une pression de dépolymérisation de polyamide 6 pD, l'obtention dans UR d'un mélange de dépolymérisation aqueux comprenant du ε-caprolactame dissous dans l'eau ; l'élimination d'un flux de sortie de réacteur liquide aqueux SR de UR, le flux SR comprenant ε-caprolactame dissous dans l'eau ; 0,8 ≤ TSF/TD ≤ 1,05 et 0,9 ≤ pSF/pD ≤ 1,05.
PCT/EP2024/065380 2023-06-06 2024-06-05 Procédé de dépolymérisation hydrolytique d'un polyamide Ceased WO2024251758A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CN202480037510.8A CN121399096A (zh) 2023-06-06 2024-06-05 用于水解解聚聚酰胺的方法
AU2024286546A AU2024286546A1 (en) 2023-06-06 2024-06-05 Process for hydrolytically depolymerizing a polyamide
KR1020267000456A KR20260019627A (ko) 2023-06-06 2024-06-05 폴리아미드를 가수분해적으로 해중합하는 방법
EP24731884.3A EP4724421A1 (fr) 2023-06-06 2024-06-05 Procédé de dépolymérisation hydrolytique d'un polyamide
MX2025014674A MX2025014674A (es) 2023-06-06 2025-12-05 Proceso para la despolimerizacion hidrolitica de una poliamida

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CN2023098586 2023-06-06
CNPCT/CN2023/098586 2023-06-06
CN2023133637 2023-11-23
CNPCT/CN2023/133637 2023-11-23

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AR (1) AR132876A1 (fr)
AU (1) AU2024286546A1 (fr)
MX (1) MX2025014674A (fr)
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Publication number Priority date Publication date Assignee Title
WO1996018613A1 (fr) * 1994-12-12 1996-06-20 Basf Aktiengesellschaft Procede d'obtention de caprolactame par division hydrolytique de polycaprolactame fondu
WO1997006137A1 (fr) * 1995-08-10 1997-02-20 Alliedsignal Inc. Recuperation de caprolactame a partir de materiaux de rebut contenant du nylon-6
WO1999011616A1 (fr) * 1997-09-03 1999-03-11 Alliedsignal Inc. Procede de purification de caprolactame obtenu a partir de la depolymerisation d'un tapis contenant une matiere polyamide
WO2008155271A1 (fr) 2007-06-20 2008-12-24 Basf Se Procédé de production de polyamides dans des extrudeuses
WO2013139827A1 (fr) 2012-03-21 2013-09-26 Basf Se Polyamides ignifuges de couleur claire
WO2023074437A1 (fr) * 2021-10-29 2023-05-04 東レ株式会社 PROCÉDÉ DE RÉCUPÉRATION DE ε-CAPROLACTAME ET D'UN OLIGOMÈRE DE POLYAMIDE 6, ET PROCÉDÉ DE PRODUCTION DE POLYAMIDE 6

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WO1996018613A1 (fr) * 1994-12-12 1996-06-20 Basf Aktiengesellschaft Procede d'obtention de caprolactame par division hydrolytique de polycaprolactame fondu
WO1997006137A1 (fr) * 1995-08-10 1997-02-20 Alliedsignal Inc. Recuperation de caprolactame a partir de materiaux de rebut contenant du nylon-6
WO1999011616A1 (fr) * 1997-09-03 1999-03-11 Alliedsignal Inc. Procede de purification de caprolactame obtenu a partir de la depolymerisation d'un tapis contenant une matiere polyamide
WO2008155271A1 (fr) 2007-06-20 2008-12-24 Basf Se Procédé de production de polyamides dans des extrudeuses
WO2013139827A1 (fr) 2012-03-21 2013-09-26 Basf Se Polyamides ignifuges de couleur claire
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AR132876A1 (es) 2025-08-06
KR20260019627A (ko) 2026-02-10
TW202506641A (zh) 2025-02-16
EP4724421A1 (fr) 2026-04-15
AU2024286546A1 (en) 2025-12-18
CN121399096A (zh) 2026-01-23

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