WO2022229129A1 - Recycling of polyester fibres from textiles - Google Patents
Recycling of polyester fibres from textiles Download PDFInfo
- Publication number
- WO2022229129A1 WO2022229129A1 PCT/EP2022/060962 EP2022060962W WO2022229129A1 WO 2022229129 A1 WO2022229129 A1 WO 2022229129A1 EP 2022060962 W EP2022060962 W EP 2022060962W WO 2022229129 A1 WO2022229129 A1 WO 2022229129A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- degrees celsius
- treatment
- fraction
- polyester
- textile product
- Prior art date
Links
- 239000004753 textile Substances 0.000 title claims abstract description 104
- 229920000728 polyester Polymers 0.000 title claims abstract description 74
- 238000004064 recycling Methods 0.000 title description 9
- 239000007787 solid Substances 0.000 claims abstract description 97
- 238000000034 method Methods 0.000 claims abstract description 53
- 239000007788 liquid Substances 0.000 claims abstract description 51
- 239000002904 solvent Substances 0.000 claims abstract description 51
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 37
- 239000000203 mixture Substances 0.000 claims abstract description 16
- 238000010438 heat treatment Methods 0.000 claims abstract description 11
- 238000002203 pretreatment Methods 0.000 claims description 96
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 58
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 47
- 239000000835 fiber Substances 0.000 claims description 40
- 230000002378 acidificating effect Effects 0.000 claims description 20
- SZXQTJUDPRGNJN-UHFFFAOYSA-N dipropylene glycol Chemical compound OCCCOCCCO SZXQTJUDPRGNJN-UHFFFAOYSA-N 0.000 claims description 14
- MTZQAGJQAFMTAQ-UHFFFAOYSA-N ethyl benzoate Chemical compound CCOC(=O)C1=CC=CC=C1 MTZQAGJQAFMTAQ-UHFFFAOYSA-N 0.000 claims description 14
- WEFZXWJJPHGTTN-UHFFFAOYSA-N methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate Chemical compound COC(=O)C(C)CCC(=O)N(C)C WEFZXWJJPHGTTN-UHFFFAOYSA-N 0.000 claims description 14
- HHVIBTZHLRERCL-UHFFFAOYSA-N sulfonyldimethane Chemical compound CS(C)(=O)=O HHVIBTZHLRERCL-UHFFFAOYSA-N 0.000 claims description 14
- 239000004744 fabric Substances 0.000 claims description 13
- 238000011282 treatment Methods 0.000 claims description 13
- SVTBMSDMJJWYQN-UHFFFAOYSA-N 2-methylpentane-2,4-diol Chemical compound CC(O)CC(C)(C)O SVTBMSDMJJWYQN-UHFFFAOYSA-N 0.000 claims description 12
- XSIFPSYPOVKYCO-UHFFFAOYSA-N butyl benzoate Chemical compound CCCCOC(=O)C1=CC=CC=C1 XSIFPSYPOVKYCO-UHFFFAOYSA-N 0.000 claims description 12
- DKMROQRQHGEIOW-UHFFFAOYSA-N Diethyl succinate Chemical compound CCOC(=O)CCC(=O)OCC DKMROQRQHGEIOW-UHFFFAOYSA-N 0.000 claims description 9
- 229940016409 methylsulfonylmethane Drugs 0.000 claims description 9
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 9
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 claims description 9
- WHIRALQRTSITMI-UJURSFKZSA-N (1s,5r)-6,8-dioxabicyclo[3.2.1]octan-4-one Chemical compound O1[C@@]2([H])OC[C@]1([H])CCC2=O WHIRALQRTSITMI-UJURSFKZSA-N 0.000 claims description 8
- FCGXLCNBWYIEAA-UHFFFAOYSA-N 1,3-benzothiazol-6-ylmethanamine Chemical compound NCC1=CC=C2N=CSC2=C1 FCGXLCNBWYIEAA-UHFFFAOYSA-N 0.000 claims description 7
- MUXOBHXGJLMRAB-UHFFFAOYSA-N Dimethyl succinate Chemical compound COC(=O)CCC(=O)OC MUXOBHXGJLMRAB-UHFFFAOYSA-N 0.000 claims description 7
- UXDDRFCJKNROTO-UHFFFAOYSA-N Glycerol 1,2-diacetate Chemical compound CC(=O)OCC(CO)OC(C)=O UXDDRFCJKNROTO-UHFFFAOYSA-N 0.000 claims description 7
- OUWSNHWQZPEFEX-UHFFFAOYSA-N diethyl glutarate Chemical compound CCOC(=O)CCCC(=O)OCC OUWSNHWQZPEFEX-UHFFFAOYSA-N 0.000 claims description 7
- GAEKPEKOJKCEMS-UHFFFAOYSA-N gamma-valerolactone Chemical compound CC1CCC(=O)O1 GAEKPEKOJKCEMS-UHFFFAOYSA-N 0.000 claims description 7
- PAPBSGBWRJIAAV-UHFFFAOYSA-N ε-Caprolactone Chemical compound O=C1CCCCCO1 PAPBSGBWRJIAAV-UHFFFAOYSA-N 0.000 claims description 7
- IBLKWZIFZMJLFL-UHFFFAOYSA-N 1-phenoxypropan-2-ol Chemical compound CC(O)COC1=CC=CC=C1 IBLKWZIFZMJLFL-UHFFFAOYSA-N 0.000 claims description 6
- QCDWFXQBSFUVSP-UHFFFAOYSA-N 2-phenoxyethanol Chemical compound OCCOC1=CC=CC=C1 QCDWFXQBSFUVSP-UHFFFAOYSA-N 0.000 claims description 6
- VIZORQUEIQEFRT-UHFFFAOYSA-N Diethyl adipate Chemical compound CCOC(=O)CCCCC(=O)OCC VIZORQUEIQEFRT-UHFFFAOYSA-N 0.000 claims description 6
- LHDWRKCOQQHAMP-UHFFFAOYSA-N butyl 3-hydroxybutanoate Chemical compound CCCCOC(=O)CC(C)O LHDWRKCOQQHAMP-UHFFFAOYSA-N 0.000 claims description 6
- 229940028356 diethylene glycol monobutyl ether Drugs 0.000 claims description 6
- 229940051250 hexylene glycol Drugs 0.000 claims description 6
- JCGNDDUYTRNOFT-UHFFFAOYSA-N oxolane-2,4-dione Chemical compound O=C1COC(=O)C1 JCGNDDUYTRNOFT-UHFFFAOYSA-N 0.000 claims description 6
- 229960005323 phenoxyethanol Drugs 0.000 claims description 6
- MOQVHOPVBREXLY-UHFFFAOYSA-N 3h-dioxol-4-ylmethanol Chemical compound OCC1=COOC1 MOQVHOPVBREXLY-UHFFFAOYSA-N 0.000 claims description 5
- 238000004042 decolorization Methods 0.000 claims description 5
- -1 polyethylene terephthalate Polymers 0.000 claims description 5
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 4
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 4
- WVDDGKGOMKODPV-ZQBYOMGUSA-N phenyl(114C)methanol Chemical compound O[14CH2]C1=CC=CC=C1 WVDDGKGOMKODPV-ZQBYOMGUSA-N 0.000 claims description 3
- BOHGAOWOIJMTPZ-UHFFFAOYSA-N 1,3-dioxolan-4-ylmethanol Chemical compound OCC1COCO1 BOHGAOWOIJMTPZ-UHFFFAOYSA-N 0.000 claims description 2
- VCKSNYNNVSOWEE-UHFFFAOYSA-N 1,3-dioxan-5-ol Chemical compound OC1COCOC1 VCKSNYNNVSOWEE-UHFFFAOYSA-N 0.000 claims 1
- 239000000047 product Substances 0.000 description 80
- 239000000975 dye Substances 0.000 description 27
- 239000000985 reactive dye Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 16
- 229920002994 synthetic fiber Polymers 0.000 description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 239000002585 base Substances 0.000 description 11
- WVDDGKGOMKODPV-UHFFFAOYSA-N Benzyl alcohol Chemical compound OCC1=CC=CC=C1 WVDDGKGOMKODPV-UHFFFAOYSA-N 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 229920000742 Cotton Polymers 0.000 description 7
- 150000001875 compounds Chemical class 0.000 description 7
- 238000006116 polymerization reaction Methods 0.000 description 7
- 239000010784 textile waste Substances 0.000 description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 238000009835 boiling Methods 0.000 description 6
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 description 6
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 230000006698 induction Effects 0.000 description 5
- 229910001220 stainless steel Inorganic materials 0.000 description 5
- 239000010935 stainless steel Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- RDOXTESZEPMUJZ-UHFFFAOYSA-N anisole Chemical compound COC1=CC=CC=C1 RDOXTESZEPMUJZ-UHFFFAOYSA-N 0.000 description 4
- 239000002738 chelating agent Substances 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 239000000049 pigment Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- CPRMKOQKXYSDML-UHFFFAOYSA-M rubidium hydroxide Chemical compound [OH-].[Rb+] CPRMKOQKXYSDML-UHFFFAOYSA-M 0.000 description 4
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- 239000000010 aprotic solvent Substances 0.000 description 3
- 235000019445 benzyl alcohol Nutrition 0.000 description 3
- HUCVOHYBFXVBRW-UHFFFAOYSA-M caesium hydroxide Chemical compound [OH-].[Cs+] HUCVOHYBFXVBRW-UHFFFAOYSA-M 0.000 description 3
- 229920002678 cellulose Polymers 0.000 description 3
- 239000001913 cellulose Substances 0.000 description 3
- XTDYIOOONNVFMA-UHFFFAOYSA-N dimethyl pentanedioate Chemical compound COC(=O)CCCC(=O)OC XTDYIOOONNVFMA-UHFFFAOYSA-N 0.000 description 3
- 239000012065 filter cake Substances 0.000 description 3
- 230000001976 improved effect Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- RQPZNWPYLFFXCP-UHFFFAOYSA-L barium dihydroxide Chemical compound [OH-].[OH-].[Ba+2] RQPZNWPYLFFXCP-UHFFFAOYSA-L 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000004043 dyeing Methods 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- UZKWTJUDCOPSNM-UHFFFAOYSA-N methoxybenzene Substances CCCCOC=C UZKWTJUDCOPSNM-UHFFFAOYSA-N 0.000 description 2
- VHRUBWHAOUIMDW-UHFFFAOYSA-N n,n-dimethyloctanamide Chemical compound CCCCCCCC(=O)N(C)C VHRUBWHAOUIMDW-UHFFFAOYSA-N 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 150000002898 organic sulfur compounds Chemical class 0.000 description 2
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- UUCCCPNEFXQJEL-UHFFFAOYSA-L strontium dihydroxide Chemical compound [OH-].[OH-].[Sr+2] UUCCCPNEFXQJEL-UHFFFAOYSA-L 0.000 description 2
- 229910001866 strontium hydroxide Inorganic materials 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- JSZOAYXJRCEYSX-UHFFFAOYSA-N 1-nitropropane Chemical compound CCC[N+]([O-])=O JSZOAYXJRCEYSX-UHFFFAOYSA-N 0.000 description 1
- MFGOFGRYDNHJTA-UHFFFAOYSA-N 2-amino-1-(2-fluorophenyl)ethanol Chemical compound NCC(O)C1=CC=CC=C1F MFGOFGRYDNHJTA-UHFFFAOYSA-N 0.000 description 1
- YEBLAXBYYVCOLT-UHFFFAOYSA-N 2-hydroxy-n,n-dimethylpropanamide Chemical compound CC(O)C(=O)N(C)C YEBLAXBYYVCOLT-UHFFFAOYSA-N 0.000 description 1
- BMYNFMYTOJXKLE-UHFFFAOYSA-N 3-azaniumyl-2-hydroxypropanoate Chemical compound NCC(O)C(O)=O BMYNFMYTOJXKLE-UHFFFAOYSA-N 0.000 description 1
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- 244000198134 Agave sisalana Species 0.000 description 1
- 235000017166 Bambusa arundinacea Nutrition 0.000 description 1
- 235000017491 Bambusa tulda Nutrition 0.000 description 1
- 244000025254 Cannabis sativa Species 0.000 description 1
- 235000012766 Cannabis sativa ssp. sativa var. sativa Nutrition 0.000 description 1
- 235000012765 Cannabis sativa ssp. sativa var. spontanea Nutrition 0.000 description 1
- 241000195493 Cryptophyta Species 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- 241000219146 Gossypium Species 0.000 description 1
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical compound Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 description 1
- 229920000433 Lyocell Polymers 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 244000082204 Phyllostachys viridis Species 0.000 description 1
- 235000015334 Phyllostachys viridis Nutrition 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000012296 anti-solvent Substances 0.000 description 1
- 239000011425 bamboo Substances 0.000 description 1
- 229910001863 barium hydroxide Inorganic materials 0.000 description 1
- 235000009120 camo Nutrition 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 235000005607 chanvre indien Nutrition 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000009295 crossflow filtration Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 239000011487 hemp Substances 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 1
- 229940071870 hydroiodic acid Drugs 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000010169 landfilling Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000001455 metallic ions Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 238000001728 nano-filtration Methods 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 239000012260 resinous material Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 238000000956 solid--liquid extraction Methods 0.000 description 1
- 230000007928 solubilization Effects 0.000 description 1
- 238000005063 solubilization Methods 0.000 description 1
- 230000003381 solubilizing effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
-
- 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
- C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
- C08J11/08—Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
- D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
- D06L4/10—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
- D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
- D06L4/30—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using reducing agents
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
- D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
- D06L4/70—Multi-step processes
- D06L4/75—Multi-step processes combined with cleaning or washing
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
- D06P5/00—Other features in dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form
- D06P5/13—Fugitive dyeing or stripping dyes
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
- D06P5/00—Other features in dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form
- D06P5/15—Locally discharging the dyes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0286—Cleaning means used for separation
- B29B2017/0289—Washing the materials in liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0293—Dissolving the materials in gases or liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
- B29K2067/003—PET, i.e. poylethylene terephthalate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/0005—Condition, form or state of moulded material or of the material to be shaped containing compounding ingredients
- B29K2105/0032—Pigments, colouring agents or opacifiyng agents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/08—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns
- B29K2105/0809—Fabrics
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0018—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
- B29K2995/002—Coloured
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/726—Fabrics
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- 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
- C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
- C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
-
- 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 recycling polyester from a textile product.
- the present invention relates to a process for providing a process for recycling polyester from a textile product comprising a blend of fibre materials.
- the textile waste is traditionally either dumped into landfill or burned.
- Reactive dye is a class of dye that is extensively used in the dying of textiles and makes a covalent bond with the polymer fibre, thereby becoming an integral part thereof.
- the term "reactive" is due to this type of dye being the only type of dye that has a reactive group, which reacts chemically with the polymer fibre molecules to form covalent bonds.
- the use of reactive dyes is increasing. However, one of the challenges with reactive dyes is the subsequent stripping from the fibres during recycling.
- an object of the present invention relates to a process for recycling polyester solid fraction from a textile product comprising a blend of fibre materials.
- the present invention to provide a process that solves the above-mentioned problems of the prior art with recovering polyester solid fractions in an easy, reliable, efficient, environmentally friendly, cheap, and fast manner.
- the solid fractions are stripped from dyes, including reactive dyes.
- one aspect of the invention relates to a process for providing a solid polyester fraction from a textile product comprising natural fibres, and polyester fibres, the process comprising the steps of:
- solid fraction is meant to include both a powder fraction and/or a fibrous fraction.
- polyester refers to homopolymers or copolymers having an ester bond between monomer units.
- a further aspect of the present invention relates to solid polyester fraction produced by the process according to the present invention.
- Another aspect relates to a process for providing at least one solid fraction from a textile product comprising a natural fibre and/or a synthetic fibre, the process comprises the steps of: (i) proving the textile product comprising a natural fibre and/or one or more synthetic fibres;
- the inventors of the present invention surprisingly found an efficient process of fractionating textile products with polyester fibre and natural fibre into individual solid fractions with a reduced amount of dye, thereby allowing for a better usage of the solid fractions.
- a first aspect of the present invention relates to a process for providing a solid polyester fraction from a textile product comprising natural fibres, and polyester fibres, the process comprising the steps of:
- Fibres are natural or synthetic substances that are significantly longer than they are wide. Fibres are used in the manufacture of other materials like textiles.
- Natural fibres may e.g., be produced by plants or algae and may include cellulose and may be provided e.g., as cotton, hemp, sisal, bamboo, viscose, lyocell, or TENCELTM.
- the textile product Before treating the textile product, the textile product may preferably be shredded to smaller pieces.
- the smaller pieces of textile product may be below approximately 10x10 cm, such as below 5x5 cm, e.g., below lxl cm.
- a decolorizing agent may be added to the textile product.
- the decolorizing agent dissolves or chemically cleaves, e.g., by hydrolysis or the like, the dye from the textile product and may thereby be separated from the first solid fraction as a first liquid fraction, e.g., by draining, centrifugation, or filtration.
- the first liquid fraction according to the present invention may comprise solubilised pigments.
- the solubilized pigments include reactive dyes.
- Reactive dyes may be a class of dyes, which makes covalent bonds with the fibres and becomes a part of the fibres. Reactive dyes are traditionally difficult to remove from textile products.
- the presence of reactive dyes in the first solid fraction is invisible to the human eye.
- the content of reactive dyes in the first solid fraction is reduced by at least 25%, such as by at least 50%, e.g., by at least 75%, such as by at least 85%, e.g., by at least 90%, such as by at least 95%, e.g., by at least 98%.
- the textile product comprising a natural fibre and polyester fibres may be subjected to a pre-treatment before adding a liquid decolorizing agent to the textile product in step (ii).
- the pre-treatment comprises one, two or three steps selected from: (a) an acidic treatment;
- the textile product is subjected to a pre-treatment before adding a liquid decolorizing agent to the textile product in step (ii); and wherein the pre treatment comprises one, two or three steps selected from:
- the pre-treatment comprises the combination of (b) an alkaline treatment and (c) a hydrogen peroxide treatment.
- the pre-treatment comprises: an acidic pre-treatment; or an acidic pre-treatment and an alkaline pre-treatment; or - an acidic pre-treatment and an alkaline pre-treatment and a hydrogen peroxide pre-treatment; or an alkaline pre-treatment; or an alkaline pre-treatment and a hydrogen peroxide pre-treatment; or a hydrogen peroxide pre-treatment.
- the pre-treatment may involve at least the acidic pre-treatment (pre-treatment (a)); or the acidic pre-treatment (pre-treatment (a)) in combination with the alkaline pre treatment (pre-treatment (b)); the acidic pre-treatment (pre-treatment (a)) in combination with the hydrogen peroxide pre-treatment (pre-treatment (c)).
- the pre-treatment may be performed simultaneously or sequentially.
- the pre-treatments are performed sequentially.
- the sequence of the combination of acidic pre-treatment (pre-treatment (a)); the alkaline pre-treatment (pre-treatment (b)); and/or the hydrogen peroxide pre-treatment (pre treatment (c)) may be optional.
- the acidic pre-treatment may be performed using a strong acid.
- the strong acid may be selected from the group consisting of HCI (hydrochloric acid); H 2 S0 (sulfuric acid); HNO3 (nitric acid); HBr (hydrobromic acid); HCI0 4 (perchloric acid); or HI (hydroiodic acid).
- HCI hydrochloric acid
- H 2 S0 sulfuric acid
- HNO3 nitric acid
- HBr hydrobromic acid
- HCI0 4 perchloric acid
- HI hydroiodic acid
- the strong acid is H 2 S0 4 (sulfuric acid).
- the concentration of the acid used in the acidic pre-treatment may have a concentration in the range of 0.1-3M (moles per litre), such as in the range of 0.3-2.5M, e.g., in the range of 0.5-2.0M, such as in the range of 0.6-1.5M, e.g., in the range of 0.75-1.0M.
- the acidic pre-treatment may preferably be performed at a temperature in the range of 20-95 degrees Celsius, such as within the range of 30-85°C, e.g., within the range of 40- 75°C, such as within the range of 50-65°C, e.g., about 60 degrees Celsius.
- the acidic pre-treatment may preferably be performed for a period in the range of 5-60 minutes, such as for a period of 15-45 minutes, e.g., for about 30 minutes. Obviously, the pre-treatment may be performed for even longer time, but without any significantly improved effect.
- the alkaline pre-treatment (pre-treatment (b)) may be performed using a strong base.
- Strong bases may be bases which completely dissociate in water into the cation and OH- (hydroxide ion).
- hydroxides of the Group I (alkali metals) and Group II (alkaline earth) metals are considered strong bases.
- the strong base may be selected from a hydroxide compound.
- the strong base may be selected from the group consisting of NaOH (sodium hydroxide); LiOH (lithium hydroxide); KOH (potassium hydroxide); RbOH (rubidium hydroxide); CsOH (cesium hydroxide); Ca(OH) 2 (calcium hydroxide); Sr(OH) 2 (strontium hydroxide); and/or Ba(OH) 2 (barium hydroxide).
- the concentration of the base used in the alkaline pre-treatment may have a concentration within the range of 5-25 wt% (weight percent), such as within the range of 8-20 wt%; e.g., within the range of 9-15 wt%, such as about 10 wt%.
- the alkaline pre-treatment may preferably be performed at a temperature within the range of 20-95 degrees Celsius, such as within the range of 30-90°C, e.g., within the range of 40-85°C, such as within the range of 60-75°C, e.g., about 70°C.
- the alkaline pre-treatment may preferably be performed for a period within the range of 5- 60 minutes, such as for a period of 15-45 minutes, e.g., for about 30 minutes.
- the hydrogen peroxide pre-treatment may be performed using a concentration of hydrogen peroxide within the range of 5-25 wt%, such as within the range of 8-20 wt%; e.g., within the range of 9-15 wt%, such as about 10 wt%.
- the hydrogen peroxide pre-treatment may include a base, preferably a strong base, e.g., a strong base as mentioned herein.
- the hydrogen peroxide solution may have a concentration of strong base in the range of 5-25 wt%, such as in the range of 8-20 wt%; e.g., in the range of 9-15 wt%, such as about 10 wt%.
- the hydrogen peroxide pre-treatment (pre-treatment (c)) may include a step of adjusting the pH-value of the hydrogen peroxide solution.
- the pH-value of the hydrogen peroxide solution may be adjusted to a pH-value in the range of pH 9-14, such as in the range of pH 10-13; e.g., pH 12.
- the hydrogen peroxide pre-treatment may preferably be performed at a temperature in the range of 20-95°Celsius (C), such as in the range of 30-90°C, e.g., in the range of 40- 85°C, such as in the range of 60-75°C, e.g., about 70°C.
- C 20-95°Celsius
- the hydrogen peroxide pre-treatment may preferably be performed for a period in the range of 5-60 minutes, such as for a period of 15-45 minutes, e.g., for about 30 minutes. Obviously, the pre-treatment may be performed for even longer time, but without any significantly improved effect.
- the acidic pre-treatment (pre-treatment (a)); the alkaline pre-treatment (pre-treatment (b)); and/or the hydrogen peroxide pre-treatment (pre-treatment (c)) may be supplemented with a chelating agent.
- the alkaline pre-treatment (pre-treatment (b)); and/or the hydrogen peroxide pre-treatment (pre-treatment (c)) may be supplemented with a chelating agent.
- a chelating agent may during the pre-treatment, and/or during the decolourization in steps (ii) or (iii), scavenges metallic ions from the pigments used and ensuring solubility of the pigments and removing silicates (e.g., Si0 2 ) and metal-ions from the textile product.
- the concentration of the chelating agent supplemented may have a concentration in the range of 1-100 mg/I, such as in the range of 5-75 mg/I, e.g., in the range of 10-60 mg/I, such as in the range of 15-50 mg/I, e.g., in the range of 25-40 mg/I, such as about 35 mg/I.
- the pre-treatment of the textile product assists in removing dyes therefrom.
- the inventors of the present invention surprisingly found that the dye of the textile product is not removed during the pre-treatment, but the pre-treatment results in an improved release and removal of dye during the following addition of the liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction.
- the first liquid fraction may comprise dyes (including reactive dyes), Si0 2 , and metals-ions that were present in the textile product.
- the first solid fraction comprises polyester and natural fibres but may also comprise other synthetic fibres.
- the inventors of the present invention surprisingly found that not only water-soluble dyes, but also water-insoluble dyes may be effectively removed from the textile product.
- the process according to the present invention showed to be extremely effective in removing reactive dyes from the textile product.
- the content of reactive dyes in the textile product may be indicated by whiteness measurements, e.g., performed according to DIN53 145 (2012).
- whiteness measurements may be made using a PCE-WSB 1 device, purchased from PCE- instruments.com, which complies with ISO 2471: 1977 (Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method).
- the textile product which has been subjected to a pre-treatment before adding the decolorizing agent to the textile product in step (ii), may after the pre-treatment be subjected to a washing step.
- the washing step may be provided to avoid the compounds used during the pre-treatment(s) of the textile product to react with the decolorizing agent.
- the washed textile product may be subjected to a drying step before adding the liquid decolorizing agent to the textile product in step (ii).
- the effect of the drying step may be to avoid diluting the liquid decolorizing agent, and/or ensuring controlling the concentration of the decolorizing agent, when added to the textile product after the textile product has been subjected to the pre-treatment.
- Step (ii) comprises adding a liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction.
- liquid decolorizing agents may preferably be selected from an aprotic solvent, such as dihydrolevoglucosenone (Cyrene), dimethyl sulfoxide (DMSO), methyl- sulfonyl-methane (DMSO2), sulfolane, or a combination thereof.
- the aprotic solvent has a boiling point above 180 degrees Celsius, such as within the range of 185-300 degrees Celsius.
- the aprotic solvent comprises (consist essentially of) an organosulfur compound.
- the organosulfur compound may preferably be selected from dimethyl sulfoxide (DMSO), methyl-sulfonyl-methane (DMSO2), sulfolane, or a combination thereof.
- the solvent used and/or the decolorizing agent used may be isolated and recycled.
- the isolation may be possible e.g., by evaporation, distillation, Membrane Cross flow filtration, OSN (organic solvent Nanofiltration), antisolvent precipitation, crystallization, or the like. Such techniques are generally known within the art.
- the decolorization performed in step (ii) is preferably performed at a temperature within the range of 130-165°C, such as in the range of 140- 160°C, e.g., about 150°C, preferably with intermediate cooling, e.g., to around 50-100 degrees Celsius.
- the decolorization is performed for a period within the range of 5-60 minutes, such as in the range of 10-50 minutes, e.g., in the range of 20-40 minutes, such as about 30 minutes.
- the heating operation may preferably be performed with flash heating for the above-mentioned time periods.
- the number of cycles of heating and cooling may be 1-10 times.
- the heating operation may in general include solvent exchange for 2-10 times (solid liquid extraction).
- a solvent is then added to the first solid fraction and the mixture.
- the inventors of the present invention have surprisingly identified a group of solvents that at a relatively narrow temperature range can dissolve the polyester fibres in the fabric. Despite different chemical structures, these solvents only work at temperatures above 170 degrees Celsius.
- the melting point of polyester is about 260 degrees Celsius. Due to each solvent's thermal stability, the upper temperature should not exceed 190 degrees Celsius.
- the mixture of the first solid fraction and the solvent is heated at a temperature between 170- 190 degrees Celsius, preferably within the range of 175-185 degrees Celsius, even more preferably at about 180 degrees Celsius, thereby providing a second solid fraction comprising the natural fibres, and a second liquid fraction comprising polyester.
- the second liquid fraction is then separated from the second solid fraction, and finally the polyester fraction is separated from the second liquid fraction, thereby providing a solid polyester fraction.
- the identified solvents suitable for solubilizing the polyester fibres in the fabric are: dihydrolevoglucosenone (Cyrene, bp. 227 degrees Celsius), dimethyl sulfoxide (DMSO, bp. 189 degrees Celsius), methyl-sulfonyl-methane (DMS0 , bp. 238 degrees Celsius), sulfolane (bp. 285 degrees Celsius), 4-valerolactone (bp. 207 degrees Celsius), 6- hexanolactone (carprolactone, bp. 241 degrees Celsius), methyl 5-(dimethylamino)-2- methyl-5-oxopentanoate (pentanoic acid, bp.
- the polyester fibres are polyethylene terephthalate fibres.
- the solvent and the decolorizing agent are the same, e.g., DMSO.
- the liquid decolorizing agent is dimethyl sulfoxide (DMSO).
- the textile product comprises cellulosic fabrics, and polyester fibres.
- the textile product essentially (such as at least 90% of the fibres) consists of fibres selected from cellulosic fabrics, and polyester fibres.
- the liquid decolorizing agent is selected from the group consisting of dihydrolevoglucosenone, dimethyl sulfoxide, methyl-sulfonyl-methane, sulfolane, 4-valerolactone, 6-hexanolactone, methyl 5-(dimethylamino)-2-methyl-5- oxopentanoate, 2-Hydroxy-A/,A/-dimethylpropanamide, isosorbide dimethyl ether, 1,3- Dioxolane-4-methanol, l,3-dioxane-5-ol, succinic acid dimethyl ester, glycerol diacetate, A/,A/-dimethyloctanamide, diethylglutarate, ethyl benzoate, 1,2-propanediol carbonate, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, diethylene glycol monobutyl ether
- Another aspect relates to a process for providing at least one solid fraction from a textile product comprising a natural fibre and/or a synthetic fibre, the process comprises the steps of:
- the decolorizing agent is used to react with and/or on the textile product at a temperature between 130-165°C.
- Yet another aspect of the present invention relates to a solid fraction obtained from a textile product and comprising a natural fibre having a degree of polymerization (DP) above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500.
- DP degree of polymerization
- Still another aspect of the present invention relates to a solid fraction obtained from a textile product and comprising a natural fibre having a degree of polymerization (DP) above 300, such as above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500, and having a whiteness of at least 50% measured by DIN53 145, preferably at least 60%, e.g., at least 70%, such as at least 80%, and more preferably at least 90%, such as at least 95%, e.g., at least 99%.
- DP degree of polymerization
- Yet another aspect of the present invention relates to a process for providing at least one solid fraction, such as e.g., polyester, from a textile product comprising a natural fibre and/or a synthetic fibre, such as e.g., polyester, the process comprises the steps of:
- step (iii) separating the decolorized textile product from the colour-fraction, providing the at least one solid fraction; wherein the textile product comprising a natural fibre and/or one or more synthetic fibres is subjected to a pre-treatment before adding a decolorizing agent to the textile product in step (ii); and wherein said pre-treatment comprises one, two or three steps selected from:
- Still another aspect of the present invention relates to a process for providing two or more solid fractions from a textile product comprising a natural fibre and a synthetic fibre, the process comprises the steps of:
- Yet another aspect of the present invention relates to the use of the solid fractions, in particular the natural fibre, according to the present invention in the preparation of a textile product.
- a further aspect of the present invention relates to a textile product comprising the solid fractions, in particular the natural fibre, according to the present invention.
- a solvent may be added to the decolorized textile product to solubilize the decolorized textile product or parts hereof, providing a solubilised fraction and an un-solubilised fraction.
- the solubilised fraction preferably comprises a second solid fraction.
- the un-solubilised fraction comprises a third solid fraction.
- the solubilised fraction preferably consists essentially of a second solid fraction, except for a minor impurity of the first solid fraction and/or the third solid fraction.
- the un-solubilised fraction consists essentially of a third solid fraction, except for a minor impurity of the first solid fraction and/or the second solid fraction.
- a minor impurity relates to a content of the solid fraction in question of at most 5 wt%, such as at most 4wt%, e.g., at most 3wt%, such as at most 2wt%, e.g., at most lwt%, such as at most 0.75wt%, e.g., at most 0.5wt%, such as at most 0.1wt%, e.g., at most 0.05wt%.
- the second solid fraction comprises (or consist essentially of) a polyester compound and/or the third solid fraction comprises (or consist essentially of) a cellulose compound.
- the polyester compound may be Polyethylene terephthalate (PET).
- the decolorization performed in step (ii) may preferably be controlled (e.g., by adjusting time, temperature, and/or chemical(s)) to avoid or limit solubility of polyester (when present in the textile product).
- the solubilization (of the solubilised fraction) may be performed at a temperature in the range of 170-200°C, such as in the range of 180-190°C, e.g., about 185°C.
- the solubilised fraction may be separated from the un-solubilised fraction.
- the resulting solubilised fraction may be subjected to a crystallisation process, providing a crystallized synthetic solid fraction.
- the synthetic solid fraction may, after being separated from the un-solubilised fraction, be crystallized be collected in a tank and cooled, e.g., to about room temperature, whereby the synthetic solid fraction may crystalise. Following the crystallisation, the crystalised synthetic solid fraction may be separated by filtration or centrifugation. The resulting isolated crystalised synthetic solid fraction may optionally be dried, before being melted into a single piece of synthetic solid fraction.
- the crystallized synthetic solid fraction may be collected as a particulate fraction and optionally dried to a powder fraction.
- the crystallization process includes the presence of the solvent and a temperature below 170°C, such as below 160°C, e.g., below 140°C, such as below 120°C, e.g., below 100°C, such as below 75°C, e.g., below 50°C, such as below 35°C, e.g., below 25°C.
- the synthetic fibre provided in step (vii) comprises (or consist essentially of) a polyester compound.
- the natural fibre provided in step (vii) comprises (or consist essentially of) a cellulose compound.
- the un-solubilised fraction may be subjected to a washing process, preferably an aqueous washing process, preferably using water. Following the washing process the un-solubilised fraction may be dried and spun to a fibre product.
- the steps of (i) adding a decolorizing agent to the textile product, providing a decolorized textile product; and separating the decolorized textile product from the colour-fraction, providing the at least one solid fraction; and adding a solvent to the decolorized textile product to solubilize the decolorized textile product or parts hereof, providing a solubilised fraction and an un-solubilised fraction; and separating the solubilised fraction and the un-solubilised fraction, may be done in the same reactor.
- the inventors of the present invention surprisingly found that the process according to the present invention resulting in a high quality of the solid fraction comprising natural fibres, which has a high and reduced, or even no, degradation of the natural fibres and at the same time a low, or no, dye left in the fibre, including no reactive dyes.
- a preferred embodiment of the present invention relates to a solid fraction obtained from a textile product comprising a natural fibre having a degree of polymerization (DP) above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500 and/or having a whiteness of at least 50% measured by DIN53 145, preferably at least 60%, e.g., at least 70%, such as at least 80%, and more preferably at least 90%, such as at least 95%, e.g., at least 99%.
- DP degree of polymerization
- 25wt% or more of the natural fibre comprises a degree of polymerization (DP) above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500, such as 30wt% or more, e.g., 40wt% or more, such as 50wt% or more, e.g., 60wt% or more, such as 70wt% or more, e.g., 80wt% or more, such as 90wt% or more, e.g., 95wt% or more, such as 98wt% or more.
- DP degree of polymerization
- less than 25wt% of the natural fibre comprises a degree of polymerization (DP) less than 500, such as less than 20wt%, e.g., less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%.
- DP degree of polymerization
- the content of one or more synthetic fibres (or fractions hereof) in the solid fraction, the natural solid fraction is less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%, such as less than 0.5wt%, e.g., less than 0.1wt%, such as less than 0.05wt%.
- - 25wt% or more of the natural fibre comprises a degree of polymerization (DP) above 300, such as above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500, such as 30wt% or more, e.g., 40wt% or more, such as 50wt% or more, e.g.,
- DP degree of polymerization
- 60wt% or more such as 70wt% or more, e.g., 80wt% or more, such as 90wt% or more, e.g., 95wt% or more, such as 98wt% or more; and/or
- - less than 25wt% of the natural fibre comprises a degree of polymerization (DP) less than 300, such as less than 20wt%, e.g., less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%; and/or
- DP degree of polymerization
- the content of one or more synthetic fibres (or fractions hereof) in the solid fraction is less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%, such as less than 0.5wt%, e.g., less than 0.1wt%, such as less than 0.05wt%.
- the solid fraction (the first solid fraction; the second solid fraction; and/or the third solid fraction) is decolourized.
- the term "solid fraction is decolourized” relates to a solid fraction comprises less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%, such as less than 0.5wt%, e.g., less than 0.1wt%, such as less than 0.05wt%.
- the dye content of the solid fraction is invisible to the human eye.
- pure black polyester fabric was mechanically shredded into separate pieces of about 1 gram.
- the solvent was added to obtain a concentration of 2wt% fibre material.
- the bluecap flasks were heated in an oil bath using a CASO TC 2100 THERMO CONTROL INDUCTION HUB for temperature control and a stainless-steel stirrer, at 200 rpm, and their content was stirred for 30 minutes.
- the remaining solid fraction was separated from the soluble fraction by filtration, weighed, and compared with the initial weight of the decoloured fibre material.
- a group of solvents were tested at 30 degrees Celsius, and then the temperature was increased with 5-10 degrees Celsius increments until the individual solvent's boiling point, but not higher than 130 degrees Celsius.
- the group of solvents were methyl acetate (bp. 57 degrees Celsius), THF (bp. 66 degrees Celsius), cyclohexanone (bp. 156 degrees Celsius), acetone (bp. 56 degrees Celsius), methylene chloride (bp. 40 degrees Celsius), 1- nitropropane (bp. 120 degrees Celsius), acetonitrile (bp. 82 degrees Celsius), formic acid (bp. 101 degrees Celsius), anisole (bp. 154 degrees Celsius), DMF (bp.
- Methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (pentanoic acid, bp. 263 degrees Celsius), 2-Hydroxy-/V,/ ⁇ /-dimethylpropanamide (N,N- Dimethyllactamide, bp. 224 degrees Celsius), isosorbide dimethyl ether (bp. 236 degrees Celsius), l,3-Dioxolane-4-methanol (bp. 193 degrees Celsius), l,3-dioxane-5-ol (bp. 193 degrees Celsius), succinic acid dimethyl ester (bp.
- diethylene glycol monobutyl ether (bp. 228 degrees Celsius), diethyl adipate (bp. 251 degrees Celsius), benzyl alcohol (bp. 205 degrees Celsius), butyl benzoate (bp. 249 degrees Celsius), butyl 3-hydroxybutyrate (bp. 242 degrees Celsius), dipropylene glycol mono /V-butyl ether (bp. 237 degrees Celsius), propylene glycol phenyl ether (bp. 243 degrees Celsius), 2-phenoxy ethanol (bp. 246 degrees Celsius), hexylene glycol (bp.
- liquid decolorizing agent dihydrolevoglucosenone, dimethyl sulfoxide, methyl-sulfonyl-methane, sulfolane, 4- valerolactone, 6-hexanolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, 2- Hydroxy-/ ⁇ /,/ ⁇ /-dimethylpropanamide, isosorbide dimethyl ether, l,3-Dioxolane-4-methanol, l,3-dioxane-5-ol, succinic acid dimethyl ester, glycerol diacetate, N,N- dimethyloctanamide, diethylglutarate, ethyl benzoate, 1,2-propanediol carbonate, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, dipropylene glycol, and succinic acid dieth
- the sample was drained in a kitchen sieve and lightly washed in demineralized water, before transferring it to another bluecap flask with a 10% NaOH solution, containing 48 mg/kg anhydrous ethylenediaminetetraacetic acid (EDTA) from Sigma Aldrich.
- EDTA anhydrous ethylenediaminetetraacetic acid
- the sample was heated to 70 degrees Celsius in the oil bath and stirred for 30 minutes.
- the sample was washed in demineralized water and dried in a Coop mini oven at 150 °C for an hour.
- the solvent was added to obtain a concentration of 5wt% fibre material.
- the bluecap flasks were heated in an oil bath using a CASO TC 2100 THERMO CONTROL INDUCTION HUB for temperature control and a stainless-steel stirrer, at 200 rpm, and their content was stirred for 30 minutes.
- the remaining solid fraction (cellulosic filter cake) was separated from the soluble fraction (still relatively warm) by filtration (e.g., using a Buchner funnel and a vacuum pump), weighed, and compared with the initial weight of the decoloured fibre material.
- the cellulosic filter cake was washed and dried, and the polyester containing solvent filtrate was collected in a bluecap flask and cooled with gentle shaking the closed bottle under lukewarm tap water. This resulted in polyester being crystallized into small white particles, that was filtered in the Buchner funnel, washed in demineralized water, and dried in a stink cabinet for 24h. All experiments resulted in a white polyester powder, and a cellulosic material.
- the sample was drained in a kitchen sieve and lightly washed in demineralized water, before transferring it to another bluecap flask with a 10% NaOH solution, containing 48 mg/kg anhydrous ethylenediaminetetraacetic acid (EDTA) from Sigma Aldrich.
- EDTA anhydrous ethylenediaminetetraacetic acid
- the sample was heated to 70 °C in the oil bath and stirred for 30 minutes.
- the sample was washed in demineralized water and dried in a Coop mini oven at 150 °C for an hour.
- the result was 3.40 g of white polyester powder, and 1.88 g of cellulosic material, of which the latter was analysed to having an ion content (ISO/IEC 17025:2017) of; Mg: 31 mg/kg (ICP/MS), Mn: 0.61 mg/kg (ICP/MS), Co: Below detection limit of 0.1 mg/kg (ICP/MS) and Cu: 1.4 mg/kg.
- the sample was drained in a kitchen sieve and washed in demineralized water, dried in a Coop mini oven for 3 hours, before treating the sample for 30 minutes in a solution of 150 °C of DMSO2(20wt%)/DMSO.
- the DMS02 was purchased from www. contact- saddle. com. The solvent was changed once in this time, at the same concentration. Then, the samples were collected and transferred to a solution of DMSO2(20wt%)/DMSO, and treated at 175 °C for 25 minutes, before they were washed and dried.
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Abstract
Process for providing a solid polyester fraction from a textile product comprising natural fibres, and polyester fibres, the process comprising the steps of: a) providing the textile product comprising natural fibres, and polyester fibres; b) adding a liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction; c) separating the first solid fraction from the first liquid fraction; d) adding a solvent to the first solid fraction and heating the mixture at a temperature between (170-190) degrees Celsius, preferably within the range of (175-185) degrees Celsius, even more preferably at about 180 degrees Celsius, thereby providing a second solid fraction comprising the natural fibres, and a second liquid fraction comprising polyester; e) separating the second liquid fraction from the second solid fraction; and e) separating the polyester fraction from the second liquid fraction, thereby providing a solid polyester fraction.
Description
RECYCLING OF POLYESTER FIBRES FROM TEXTILES
Technical field of the invention The present invention relates to a process for recycling polyester from a textile product. In particular, the present invention relates to a process for providing a process for recycling polyester from a textile product comprising a blend of fibre materials. Background of the invention
Around 85% of all textiles thrown away amounts in 2017 to roughly 13 million tonnes in US alone.
The textile waste is traditionally either dumped into landfill or burned.
Globally, it is estimated that 92 million tonnes of textile waste are created each year and is equivalent to one rubbish truck filled with clothes ending up on landfill sites every second. By 2030, it is expected that more than 134 million tonnes of textiles are discarded every year.
Disposal of such large volumes of textile waste is an increasing problem for the apparel industry. The rising costs, reduction in available space, and concern for the environment makes the burning and landfilling of textile waste dwindling options. Reuse or recycling of the fibres from textiles has been investigated for decades and several methods exists. However, a large percentage of the textile waste comprises blends of fibres such as polyester/cellulosic fabrics, e.g., polyester/cotton and polyester/rayon blends but also other fibres may be included. The reuse or recycling of the individual blended materials is complicated by the fact that there are inherent differences in the physical properties and composition of the components. Additionally, the fabrics are treated with resinous materials and other finishing compounds, such as dyes. This makes it nearly impossible to find potential commercial end uses for this material other than rags or cloth scraps, which are of little monetary value.
Therefore, there is an interest in the industry for providing potential methods of recycling textile waste comprising polyester, such as polyester/cotton fabric blends, which may be reused e.g., in textiles. Another challenge of reusing textile waste comprising blends of fibres is the presence of dye in the textile.
There are primarily two types of dyes, namely water-soluble dyes and water-insoluble dyes.
When it comes to dyeing fibres, some fibres adhere to and accept dyes easily, while others do not. Depending on the purpose one is seeking to achieve by dyeing the fabric, and the type of dye one is planning to use, very different processes are needed. Reactive dye is a class of dye that is extensively used in the dying of textiles and makes a covalent bond with the polymer fibre, thereby becoming an integral part thereof. The term "reactive" is due to this type of dye being the only type of dye that has a reactive group, which reacts chemically with the polymer fibre molecules to form covalent bonds. The use of reactive dyes is increasing. However, one of the challenges with reactive dyes is the subsequent stripping from the fibres during recycling. Traditionally, it is believed that reactive dye cannot be satisfactorily stripped from the fibre due to the covalent bond between dye molecule and fibre. Since stripping of the dyes including the reactive dyes becomes necessary when textiles are to be reused - a satisfactorily stripping of reactive dyes from the textile fibres is therefore desirable.
Hence, it is desirable to provide a process for recovering the polyester solid fractions from a textile product, which are decoloured, which process is easy, reliable, efficient, environmentally friendly, cheap, and fast would be advantageous.
Summary of the invention
Thus, an object of the present invention relates to a process for recycling polyester solid fraction from a textile product comprising a blend of fibre materials.
In particular, it is an object of the present invention to provide a process that solves the above-mentioned problems of the prior art with recovering polyester solid fractions in an
easy, reliable, efficient, environmentally friendly, cheap, and fast manner. Preferably, the solid fractions are stripped from dyes, including reactive dyes.
Thus, one aspect of the invention relates to a process for providing a solid polyester fraction from a textile product comprising natural fibres, and polyester fibres, the process comprising the steps of:
(i) proving the textile product comprising natural fibres, and polyester fibres; (ii) adding a liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction;
(iii) separating the first solid fraction from the first liquid fraction; (iv) adding a solvent to the first solid fraction and heating the mixture at a temperature between 170-190 degrees Celsius, preferably within the range of 175-185 degrees Celsius, even more preferably at about 180 degrees Celsius, thereby providing a second solid fraction comprising the natural fibres, and a second liquid fraction comprising polyester;
(v) separating the second liquid fraction from the second solid fraction; and
(vi) separating the polyester fraction from the second liquid fraction, thereby providing a solid polyester fraction.
In the present context, the term "solid fraction" is meant to include both a powder fraction and/or a fibrous fraction.
In the present context, the term "polyester" refers to homopolymers or copolymers having an ester bond between monomer units.
A further aspect of the present invention relates to solid polyester fraction produced by the process according to the present invention. Another aspect relates to a process for providing at least one solid fraction from a textile product comprising a natural fibre and/or a synthetic fibre, the process comprises the steps of:
(i) proving the textile product comprising a natural fibre and/or one or more synthetic fibres;
(ii) adding a decolorizing agent to the textile product, providing a decolorized textile product;
(iii) separating the decolorized textile product from the colour-fraction, thereby providing the at least one solid fraction. The present invention will now be described in more detail in the following.
Detailed description of the invention
Accordingly, the inventors of the present invention surprisingly found an efficient process of fractionating textile products with polyester fibre and natural fibre into individual solid fractions with a reduced amount of dye, thereby allowing for a better usage of the solid fractions.
Hence, a first aspect of the present invention relates to a process for providing a solid polyester fraction from a textile product comprising natural fibres, and polyester fibres, the process comprising the steps of:
(i) proving the textile product comprising natural fibres, and polyester fibres; (ii) adding a liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction;
(iii) separating the first solid fraction from the first liquid fraction;
(iv) adding a solvent to the first solid fraction and heating the mixture at a temperature between 170-190 degrees Celsius, preferably within the range of 175-185 degrees Celsius, even more preferably at about 180 degrees Celsius, thereby providing a second solid fraction comprising the natural fibres, and a second liquid fraction comprising polyester;
(v) separating the second liquid fraction from the second solid fraction; and
(vi) separating the polyester fraction from the second liquid fraction, thereby providing a solid polyester fraction.
Fibres are natural or synthetic substances that are significantly longer than they are wide. Fibres are used in the manufacture of other materials like textiles.
Natural fibres may e.g., be produced by plants or algae and may include cellulose and may be provided e.g., as cotton, hemp, sisal, bamboo, viscose, lyocell, or TENCEL™.
Before treating the textile product, the textile product may preferably be shredded to smaller pieces. Preferably the smaller pieces of textile product may be below approximately 10x10 cm, such as below 5x5 cm, e.g., below lxl cm.
As mentioned herein, the removal of dyes is of outmost importance for providing a high value polyester solid fraction. Hence, for removing the dye(s) from the polyester solid fraction, a decolorizing agent may be added to the textile product. Preferably, the decolorizing agent dissolves or chemically cleaves, e.g., by hydrolysis or the like, the dye from the textile product and may thereby be separated from the first solid fraction as a first liquid fraction, e.g., by draining, centrifugation, or filtration.
The first liquid fraction according to the present invention may comprise solubilised pigments. Preferably, the solubilized pigments include reactive dyes.
Reactive dyes may be a class of dyes, which makes covalent bonds with the fibres and becomes a part of the fibres. Reactive dyes are traditionally difficult to remove from textile products.
In an embodiment of the present invention, the presence of reactive dyes in the first solid fraction is invisible to the human eye.
In a further embodiment of the present invention the content of reactive dyes in the first solid fraction is reduced by at least 25%, such as by at least 50%, e.g., by at least 75%, such as by at least 85%, e.g., by at least 90%, such as by at least 95%, e.g., by at least 98%.
In order to further improve solubility and/or removal of dyes, in particular reactive dyes, when the decolorizing agent is added to the textile product, the textile product comprising a natural fibre and polyester fibres may be subjected to a pre-treatment before adding a liquid decolorizing agent to the textile product in step (ii).
In an embodiment of the present invention the pre-treatment comprises one, two or three steps selected from: (a) an acidic treatment;
(b) an alkaline treatment;
(c) a hydrogen peroxide;
(d) or a combination of (a), (b) and (c). In one or more embodiments, the textile product is subjected to a pre-treatment before adding a liquid decolorizing agent to the textile product in step (ii); and wherein the pre treatment comprises one, two or three steps selected from:
(a) an acidic treatment; (b) an alkaline treatment;
(c) a hydrogen peroxide;
(d) or a combination of (a), (b) and (c).
In one or more embodiments, the pre-treatment comprises the combination of (b) an alkaline treatment and (c) a hydrogen peroxide treatment.
In yet an embodiment of the present invention the pre-treatment comprises: an acidic pre-treatment; or an acidic pre-treatment and an alkaline pre-treatment; or - an acidic pre-treatment and an alkaline pre-treatment and a hydrogen peroxide pre-treatment; or an alkaline pre-treatment; or an alkaline pre-treatment and a hydrogen peroxide pre-treatment; or a hydrogen peroxide pre-treatment.
Preferably, the pre-treatment may involve at least the acidic pre-treatment (pre-treatment (a)); or the acidic pre-treatment (pre-treatment (a)) in combination with the alkaline pre treatment (pre-treatment (b)); the acidic pre-treatment (pre-treatment (a)) in combination with the hydrogen peroxide pre-treatment (pre-treatment (c)).
When the pre-treatment involves a combination of the acidic pre-treatment (pre-treatment (a)); the alkaline pre-treatment (pre-treatment (b)); and/or the hydrogen peroxide pre treatment (pre-treatment (c)), the pre-treatment may be performed simultaneously or sequentially. Preferably, the pre-treatments are performed sequentially.
The sequence of the combination of acidic pre-treatment (pre-treatment (a)); the alkaline pre-treatment (pre-treatment (b)); and/or the hydrogen peroxide pre-treatment (pre treatment (c)) may be optional.
The acidic pre-treatment (pre-treatment (a)) may be performed using a strong acid. The strong acid may be selected from the group consisting of HCI (hydrochloric acid); H2S0 (sulfuric acid); HNO3 (nitric acid); HBr (hydrobromic acid); HCI04 (perchloric acid); or HI (hydroiodic acid). Preferably, the strong acid is H2S04 (sulfuric acid).
In an embodiment of the present invention the concentration of the acid used in the acidic pre-treatment may have a concentration in the range of 0.1-3M (moles per litre), such as in the range of 0.3-2.5M, e.g., in the range of 0.5-2.0M, such as in the range of 0.6-1.5M, e.g., in the range of 0.75-1.0M.
The acidic pre-treatment may preferably be performed at a temperature in the range of 20-95 degrees Celsius, such as within the range of 30-85°C, e.g., within the range of 40- 75°C, such as within the range of 50-65°C, e.g., about 60 degrees Celsius. The acidic pre-treatment may preferably be performed for a period in the range of 5-60 minutes, such as for a period of 15-45 minutes, e.g., for about 30 minutes. Obviously, the pre-treatment may be performed for even longer time, but without any significantly improved effect. The alkaline pre-treatment (pre-treatment (b)) may be performed using a strong base. Strong bases may be bases which completely dissociate in water into the cation and OH- (hydroxide ion). In an embodiment of the present invention hydroxides of the Group I (alkali metals) and Group II (alkaline earth) metals are considered strong bases. In a further embodiment of the present invention the strong base may be selected from a hydroxide compound. Preferably, the strong base may be selected from the group consisting of NaOH (sodium hydroxide); LiOH (lithium hydroxide); KOH (potassium hydroxide); RbOH (rubidium hydroxide); CsOH (cesium hydroxide); Ca(OH)2 (calcium hydroxide); Sr(OH)2 (strontium hydroxide); and/or Ba(OH)2 (barium hydroxide).
In an embodiment of the present invention the concentration of the base used in the alkaline pre-treatment may have a concentration within the range of 5-25 wt% (weight percent), such as within the range of 8-20 wt%; e.g., within the range of 9-15 wt%, such as about 10 wt%.
The alkaline pre-treatment may preferably be performed at a temperature within the range of 20-95 degrees Celsius, such as within the range of 30-90°C, e.g., within the range of 40-85°C, such as within the range of 60-75°C, e.g., about 70°C.
The alkaline pre-treatment may preferably be performed for a period within the range of 5- 60 minutes, such as for a period of 15-45 minutes, e.g., for about 30 minutes.
The hydrogen peroxide pre-treatment (pre-treatment (c)) may be performed using a concentration of hydrogen peroxide within the range of 5-25 wt%, such as within the range of 8-20 wt%; e.g., within the range of 9-15 wt%, such as about 10 wt%.
The hydrogen peroxide pre-treatment (pre-treatment (c)) may include a base, preferably a strong base, e.g., a strong base as mentioned herein. Preferably, the hydrogen peroxide solution may have a concentration of strong base in the range of 5-25 wt%, such as in the range of 8-20 wt%; e.g., in the range of 9-15 wt%, such as about 10 wt%.
The hydrogen peroxide pre-treatment (pre-treatment (c)) may include a step of adjusting the pH-value of the hydrogen peroxide solution. Preferably, the pH-value of the hydrogen peroxide solution may be adjusted to a pH-value in the range of pH 9-14, such as in the range of pH 10-13; e.g., pH 12.
The hydrogen peroxide pre-treatment may preferably be performed at a temperature in the range of 20-95°Celsius (C), such as in the range of 30-90°C, e.g., in the range of 40- 85°C, such as in the range of 60-75°C, e.g., about 70°C.
The hydrogen peroxide pre-treatment may preferably be performed for a period in the range of 5-60 minutes, such as for a period of 15-45 minutes, e.g., for about 30 minutes. Obviously, the pre-treatment may be performed for even longer time, but without any significantly improved effect.
The acidic pre-treatment (pre-treatment (a)); the alkaline pre-treatment (pre-treatment (b)); and/or the hydrogen peroxide pre-treatment (pre-treatment (c)) may be supplemented with a chelating agent.
Preferably, the alkaline pre-treatment (pre-treatment (b)); and/or the hydrogen peroxide pre-treatment (pre-treatment (c)) may be supplemented with a chelating agent. Sodium carbonate has proven particularly efficient at dissolving silicate particles.
The chelating agent may during the pre-treatment, and/or during the decolourization in steps (ii) or (iii), scavenges metallic ions from the pigments used and ensuring solubility of the pigments and removing silicates (e.g., Si02) and metal-ions from the textile product.
In an embodiment of the present invention the concentration of the chelating agent supplemented may have a concentration in the range of 1-100 mg/I, such as in the range of 5-75 mg/I, e.g., in the range of 10-60 mg/I, such as in the range of 15-50 mg/I, e.g., in the range of 25-40 mg/I, such as about 35 mg/I.
The pre-treatment of the textile product assists in removing dyes therefrom. Without being bound by theory, the inventors of the present invention surprisingly found that the dye of the textile product is not removed during the pre-treatment, but the pre-treatment results in an improved release and removal of dye during the following addition of the liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction. The first liquid fraction may comprise dyes (including reactive dyes), Si02, and metals-ions that were present in the textile product. The first solid fraction comprises polyester and natural fibres but may also comprise other synthetic fibres.
The inventors of the present invention surprisingly found that not only water-soluble dyes, but also water-insoluble dyes may be effectively removed from the textile product. In particular, the process according to the present invention showed to be extremely effective in removing reactive dyes from the textile product.
The content of reactive dyes in the textile product may be indicated by whiteness measurements, e.g., performed according to DIN53 145 (2012). Alternatively, whiteness measurements may be made using a PCE-WSB 1 device, purchased from PCE- instruments.com, which complies with ISO 2471: 1977 (Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method).
In an embodiment of the present invention the textile product, which has been subjected to a pre-treatment before adding the decolorizing agent to the textile product in step (ii), may after the pre-treatment be subjected to a washing step. The washing step may be provided to avoid the compounds used during the pre-treatment(s) of the textile product to react with the decolorizing agent.
In an embodiment of the present invention the washed textile product may be subjected to a drying step before adding the liquid decolorizing agent to the textile product in step (ii).
The effect of the drying step may be to avoid diluting the liquid decolorizing agent, and/or ensuring controlling the concentration of the decolorizing agent, when added to the textile product after the textile product has been subjected to the pre-treatment.
Step (ii) comprises adding a liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction.
Suitable examples of liquid decolorizing agents may preferably be selected from an aprotic solvent, such as dihydrolevoglucosenone (Cyrene), dimethyl sulfoxide (DMSO), methyl- sulfonyl-methane (DMSO2), sulfolane, or a combination thereof. Preferably, the aprotic solvent has a boiling point above 180 degrees Celsius, such as within the range of 185-300 degrees Celsius. Preferably, the aprotic solvent comprises (consist essentially of) an organosulfur compound. The organosulfur compound may preferably be selected from dimethyl sulfoxide (DMSO), methyl-sulfonyl-methane (DMSO2), sulfolane, or a combination thereof.
Preferably the solvent used and/or the decolorizing agent used may be isolated and recycled. The isolation may be possible e.g., by evaporation, distillation, Membrane Cross flow filtration, OSN (organic solvent Nanofiltration), antisolvent precipitation, crystallization, or the like. Such techniques are generally known within the art.
In one or more embodiments, the decolorization performed in step (ii) is preferably performed at a temperature within the range of 130-165°C, such as in the range of 140- 160°C, e.g., about 150°C, preferably with intermediate cooling, e.g., to around 50-100 degrees Celsius. Preferably, the decolorization is performed for a period within the range of 5-60 minutes, such as in the range of 10-50 minutes, e.g., in the range of 20-40 minutes, such as about 30 minutes. The heating operation may preferably be performed with flash heating for the above-mentioned time periods. The number of cycles of heating and cooling may be 1-10 times. The heating operation may in general include solvent exchange for 2-10 times (solid liquid extraction).
A solvent is then added to the first solid fraction and the mixture. The inventors of the present invention have surprisingly identified a group of solvents that at a relatively narrow temperature range can dissolve the polyester fibres in the fabric. Despite different chemical structures, these solvents only work at temperatures above 170 degrees Celsius. The melting point of polyester is about 260 degrees Celsius. Due to each solvent's thermal stability, the upper temperature should not exceed 190 degrees Celsius. Preferably, the mixture of the first solid fraction and the solvent is heated at a temperature between 170- 190 degrees Celsius, preferably within the range of 175-185 degrees Celsius, even more
preferably at about 180 degrees Celsius, thereby providing a second solid fraction comprising the natural fibres, and a second liquid fraction comprising polyester. The second liquid fraction is then separated from the second solid fraction, and finally the polyester fraction is separated from the second liquid fraction, thereby providing a solid polyester fraction.
The identified solvents suitable for solubilizing the polyester fibres in the fabric are: dihydrolevoglucosenone (Cyrene, bp. 227 degrees Celsius), dimethyl sulfoxide (DMSO, bp. 189 degrees Celsius), methyl-sulfonyl-methane (DMS0 , bp. 238 degrees Celsius), sulfolane (bp. 285 degrees Celsius), 4-valerolactone (bp. 207 degrees Celsius), 6- hexanolactone (carprolactone, bp. 241 degrees Celsius), methyl 5-(dimethylamino)-2- methyl-5-oxopentanoate (pentanoic acid, bp. 263 degrees Celsius), 2-Hydroxy-/V,/V- dimethylpropanamide (A^/V-Dimethyllactamide, bp. 224 degrees Celsius), isosorbide dimethyl ether (bp. 236 degrees Celsius), l,3-Dioxolane-4-methanol (bp. 193 degrees Celsius), l,3-dioxane-5-ol (bp. 193 degrees Celsius), succinic acid dimethyl ester (bp. 200 degrees Celsius), dimethyl glutarate (bp. 216 degrees Celsius), glycerol diacetate, N,N- dimethyloctanamide (bp. 234 degrees Celsius), diethylglutarate (bp. 237 degrees Celsius), ethyl benzoate (bp. 212 degrees Celsius), 1,2-propanediol carbonate (bp. 240 degrees Celsius), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Polarclean, bp. 237 degrees Celsius), diethyl succinate (bp. 218 degrees Celsius), diethylene glycol monobutyl ether (bp. 228 degrees Celsius), diethyl adipate (bp. 251 degrees Celsius), benzyl alcohol (bp. 205 degrees Celsius), butyl benzoate (bp. 249 degrees Celsius), butyl 3- hydroxybutyrate (bp. 242 degrees Celsius), dipropylene glycol mono /V-butyl ether (bp.
237 degrees Celsius), dipropylene glycol (bp. 227 degrees Celsius), propylene glycol phenyl ether (bp. 243 degrees Celsius), 2-phenoxy ethanol (bp. 246 degrees Celsius), hexylene glycol (bp. 197 degrees Celsius), cyclademol (bp. 215 degrees Celsius), CH302C(CH2)nC02CH3 (n = 2,3,4, bp. 196-225 degrees Celsius), or a combination thereof.
In one or more embodiments, the polyester fibres are polyethylene terephthalate fibres.
In one or more embodiments, the solvent and the decolorizing agent are the same, e.g., DMSO.
In one or more embodiments, the liquid decolorizing agent is dimethyl sulfoxide (DMSO).
In one or more embodiments, the textile product comprises cellulosic fabrics, and polyester fibres.
In one or more embodiments, the textile product essentially (such as at least 90% of the fibres) consists of fibres selected from cellulosic fabrics, and polyester fibres.
In one or more embodiments, the liquid decolorizing agent is selected from the group consisting of dihydrolevoglucosenone, dimethyl sulfoxide, methyl-sulfonyl-methane, sulfolane, 4-valerolactone, 6-hexanolactone, methyl 5-(dimethylamino)-2-methyl-5- oxopentanoate, 2-Hydroxy-A/,A/-dimethylpropanamide, isosorbide dimethyl ether, 1,3- Dioxolane-4-methanol, l,3-dioxane-5-ol, succinic acid dimethyl ester, glycerol diacetate, A/,A/-dimethyloctanamide, diethylglutarate, ethyl benzoate, 1,2-propanediol carbonate, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, diethylene glycol monobutyl ether, diethyl adipate, benzyl alcohol, butyl benzoate, butyl 3-hydroxybutyrate, dipropylene glycol mono /V-butyl ether, dipropylene glycol, propylene glycol phenyl ether, 2-phenoxy ethanol, hexylene glycol, cyclademol, CH302C(CH2)nC02CH3, where n=2, 3, or 4, succinic acid diethyl ester, or a combination thereof.
Another aspect relates to a process for providing at least one solid fraction from a textile product comprising a natural fibre and/or a synthetic fibre, the process comprises the steps of:
(i) proving the textile product comprising a natural fibre and/or one or more synthetic fibres;
(ii) adding a decolorizing agent to the textile product, providing a decolorized textile product;
(iii) separating the decolorized textile product from the colour-fraction, thereby providing the at least one solid fraction.
Preferably, the decolorizing agent is used to react with and/or on the textile product at a temperature between 130-165°C.
Yet another aspect of the present invention relates to a solid fraction obtained from a textile product and comprising a natural fibre having a degree of polymerization (DP) above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500.
Still another aspect of the present invention relates to a solid fraction obtained from a textile product and comprising a natural fibre having a degree of polymerization (DP) above 300, such as above 500, e.g., above 1000, such as above 1500, e.g., above 2000,
such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500, and having a whiteness of at least 50% measured by DIN53 145, preferably at least 60%, e.g., at least 70%, such as at least 80%, and more preferably at least 90%, such as at least 95%, e.g., at least 99%.
Yet another aspect of the present invention relates to a process for providing at least one solid fraction, such as e.g., polyester, from a textile product comprising a natural fibre and/or a synthetic fibre, such as e.g., polyester, the process comprises the steps of:
(i) proving the textile product comprising a natural fibre and/or one or more synthetic fibres;
(ii) adding a decolorizing agent to the textile product, providing a decolorized textile product;
(iii) separating the decolorized textile product from the colour-fraction, providing the at least one solid fraction; wherein the textile product comprising a natural fibre and/or one or more synthetic fibres is subjected to a pre-treatment before adding a decolorizing agent to the textile product in step (ii); and wherein said pre-treatment comprises one, two or three steps selected from:
(a) an acidic treatment;
(b) an alkaline treatment;
(c) a hydrogen peroxide;
(d) or a combination of (a), (b) and (c).
Still another aspect of the present invention relates to a process for providing two or more solid fractions from a textile product comprising a natural fibre and a synthetic fibre, the process comprises the steps of:
(i) proving the textile product comprising the natural fibre and the synthetic fibres;
(ii) adding a decolorizing agent to the textile product;
(iii) allowing the decolorizing agent to react with the textile product at a temperature between 130-165°C, providing a decolorized textile product;
(iv) separating the decolorized textile product (solid fraction) from the colour- fraction (liquid fraction),
(v) adding a solvent to the decolorized textile product,
(vi) allowing the solvent to react with and/or on the decolorized textile product at a temperature between 170-200°C, preferably, 170-190 degrees Celsius, thereby providing a solubilised fraction and an un-solubilised fraction; (vii) separating the solubilised fraction (liquid fraction) from the un-solubilised fraction (solid fraction), thereby providing a solubilised fraction comprising the synthetic fibre, and an un-solubilised fraction comprising the natural fibre.
Yet another aspect of the present invention relates to the use of the solid fractions, in particular the natural fibre, according to the present invention in the preparation of a textile product.
A further aspect of the present invention relates to a textile product comprising the solid fractions, in particular the natural fibre, according to the present invention.
In an embodiment of the present invention a solvent may be added to the decolorized textile product to solubilize the decolorized textile product or parts hereof, providing a solubilised fraction and an un-solubilised fraction. The solubilised fraction preferably comprises a second solid fraction. The un-solubilised fraction comprises a third solid fraction.
In a further embodiment of the present invention the solubilised fraction preferably consists essentially of a second solid fraction, except for a minor impurity of the first solid fraction and/or the third solid fraction.
In yet an embodiment of the present invention the un-solubilised fraction consists essentially of a third solid fraction, except for a minor impurity of the first solid fraction and/or the second solid fraction. In the context of the present invention the term "a minor impurity" relates to a content of the solid fraction in question of at most 5 wt%, such as at most 4wt%, e.g., at most 3wt%, such as at most 2wt%, e.g., at most lwt%, such as at most 0.75wt%, e.g., at most 0.5wt%, such as at most 0.1wt%, e.g., at most 0.05wt%.
In an embodiment of the present invention the second solid fraction comprises (or consist essentially of) a polyester compound and/or the third solid fraction comprises (or consist essentially of) a cellulose compound.
The polyester compound may be Polyethylene terephthalate (PET).
The decolorization performed in step (ii) may preferably be controlled (e.g., by adjusting time, temperature, and/or chemical(s)) to avoid or limit solubility of polyester (when present in the textile product).
In an embodiment of the present invention the solubilization (of the solubilised fraction) may be performed at a temperature in the range of 170-200°C, such as in the range of 180-190°C, e.g., about 185°C.
When solubilised, the solubilised fraction may be separated from the un-solubilised fraction.
The resulting solubilised fraction may be subjected to a crystallisation process, providing a crystallized synthetic solid fraction.
In an embodiment of the present invention the synthetic solid fraction may, after being separated from the un-solubilised fraction, be crystallized be collected in a tank and cooled, e.g., to about room temperature, whereby the synthetic solid fraction may crystalise. Following the crystallisation, the crystalised synthetic solid fraction may be separated by filtration or centrifugation. The resulting isolated crystalised synthetic solid fraction may optionally be dried, before being melted into a single piece of synthetic solid fraction.
The crystallized synthetic solid fraction may be collected as a particulate fraction and optionally dried to a powder fraction. Preferably, the crystallization process includes the presence of the solvent and a temperature below 170°C, such as below 160°C, e.g., below 140°C, such as below 120°C, e.g., below 100°C, such as below 75°C, e.g., below 50°C, such as below 35°C, e.g., below 25°C.
In an embodiment of the present invention the synthetic fibre provided in step (vii) comprises (or consist essentially of) a polyester compound.
In yet an embodiment of the present invention the natural fibre provided in step (vii) comprises (or consist essentially of) a cellulose compound.
In an embodiment of the present invention the un-solubilised fraction may be subjected to a washing process, preferably an aqueous washing process, preferably using water. Following the washing process the un-solubilised fraction may be dried and spun to a fibre product.
In an embodiment of the present invention the steps of (i) adding a decolorizing agent to the textile product, providing a decolorized textile product; and separating the decolorized textile product from the colour-fraction, providing the at least one solid fraction; and adding a solvent to the decolorized textile product to solubilize the decolorized textile product or parts hereof, providing a solubilised fraction and an un-solubilised fraction; and separating the solubilised fraction and the un-solubilised fraction, may be done in the same reactor.
The inventors of the present invention surprisingly found that the process according to the present invention resulting in a high quality of the solid fraction comprising natural fibres, which has a high and reduced, or even no, degradation of the natural fibres and at the same time a low, or no, dye left in the fibre, including no reactive dyes.
Thus, a preferred embodiment of the present invention relates to a solid fraction obtained from a textile product comprising a natural fibre having a degree of polymerization (DP) above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500 and/or having a whiteness of at least 50% measured by DIN53 145, preferably at least 60%, e.g., at least 70%, such as at least 80%, and more preferably at least 90%, such as at least 95%, e.g., at least 99%.
In an embodiment of the present invention 25wt% or more of the natural fibre comprises a degree of polymerization (DP) above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500, such as 30wt% or more, e.g., 40wt% or more, such as 50wt% or more, e.g., 60wt% or more, such as 70wt% or more, e.g., 80wt% or more, such as 90wt% or more, e.g., 95wt% or more, such as 98wt% or more.
In yet an embodiment of the present invention less than 25wt% of the natural fibre comprises a degree of polymerization (DP) less than 500, such as less than 20wt%, e.g., less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%.
Preferably, the content of one or more synthetic fibres (or fractions hereof) in the solid fraction, the natural solid fraction, is less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%, such as less than 0.5wt%, e.g., less than 0.1wt%, such as less than 0.05wt%.
In yet an embodiment of the present invention:
- 25wt% or more of the natural fibre comprises a degree of polymerization (DP) above 300, such as above 500, e.g., above 1000, such as above 1500, e.g., above 2000, such as above 2500, e.g., above 3000, such as above 3500, e.g., above 4000, such as above 4500, such as 30wt% or more, e.g., 40wt% or more, such as 50wt% or more, e.g.,
60wt% or more, such as 70wt% or more, e.g., 80wt% or more, such as 90wt% or more, e.g., 95wt% or more, such as 98wt% or more; and/or
- less than 25wt% of the natural fibre comprises a degree of polymerization (DP) less than 300, such as less than 20wt%, e.g., less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%; and/or
- the content of one or more synthetic fibres (or fractions hereof) in the solid fraction is less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%, such as less than 0.5wt%, e.g., less than 0.1wt%, such as less than 0.05wt%.
In an embodiment of the present invention, the solid fraction (the first solid fraction; the second solid fraction; and/or the third solid fraction) is decolourized. In the context of the present invention the term "solid fraction is decolourized" relates to a solid fraction comprises less than 15wt%, such as less than 10wt%, e.g., less than 5wt%, such as less than 2wt%, e.g., less than lwt%, such as less than 0.5wt%, e.g., less than 0.1wt%, such as less than 0.05wt%. Preferably, the dye content of the solid fraction is invisible to the human eye.
It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention. Examples
1) In one example, pure black polyester fabric was mechanically shredded into separate pieces of about 1 gram. First, each sample was transferred to a bluecap bottle with dimethyl sulfoxide >=99% (DMSO) from Sigma Aldrich, at a fibre concentration of 0.5wt%
and "flash" heated to 150 degrees Celsius three times within 30 minutes, with intermediate cooling to around 80-90 degrees Celsius. Two solvent exchanges were made, and the flash heating procedure was repeated both times, each time creating a decreasingly coloured fraction of used solvent.
2) Decoloured samples prepared from the method in Example 1) were transferred to bluecap flasks, and different solvents purchased from Sigma-Aldrich were tested for their properties to dissolve the polyester fraction of the samples.
The solvent was added to obtain a concentration of 2wt% fibre material. The bluecap flasks were heated in an oil bath using a CASO TC 2100 THERMO CONTROL INDUCTION HUB for temperature control and a stainless-steel stirrer, at 200 rpm, and their content was stirred for 30 minutes. The remaining solid fraction was separated from the soluble fraction by filtration, weighed, and compared with the initial weight of the decoloured fibre material.
Initially, a group of solvents were tested at 30 degrees Celsius, and then the temperature was increased with 5-10 degrees Celsius increments until the individual solvent's boiling point, but not higher than 130 degrees Celsius. The group of solvents were methyl acetate (bp. 57 degrees Celsius), THF (bp. 66 degrees Celsius), cyclohexanone (bp. 156 degrees Celsius), acetone (bp. 56 degrees Celsius), methylene chloride (bp. 40 degrees Celsius), 1- nitropropane (bp. 120 degrees Celsius), acetonitrile (bp. 82 degrees Celsius), formic acid (bp. 101 degrees Celsius), anisole (bp. 154 degrees Celsius), DMF (bp. 153 degrees Celsius), dihydrolevoglucosenone (Cyrene, bp. 227 degrees Celsius), dimethyl sulfoxide (DMSO, bp. 189 degrees Celsius), methyl-sulfonyl-methane (DMS0 , bp. 238 degrees Celsius), sulfolane (bp. 285 degrees Celsius), 4-valerolactone (bp. 207 degrees Celsius), 6-hexanolactone (carprolactone, bp. 241 degrees Celsius). None of the solvents worked.
The same group of solvents was reduced to the solvents with a boiling point above 140 degrees Celsius, and the experiment was repeated with higher temperatures, i.e., until the individual solvent's boiling point, but not higher than 190 degrees Celsius. Here, it was found that none of the solvents worked below 170 degrees Celsius, but surprisingly, some of them started to work at 180 degrees Celsius, and even more of them at 190 degrees Celsius. Cyclohexanone (bp. 156 degrees Celsius), DMF (bp. 153 degrees Celsius), and anisole (bp. 154 degrees Celsius) did not work, but dihydrolevoglucosenone (Cyrene, bp. 227 degrees Celsius), dimethyl sulfoxide (DMSO, bp. 189 degrees Celsius), methyl- sulfonyl-methane (DMSO2, bp. 238 degrees Celsius), sulfolane (bp. 285 degrees Celsius), 4-valerolactone (bp. 207 degrees Celsius), and 6-hexanolactone (carprolactone, bp. 241 degrees Celsius) worked at the elevated temperatures.
As there seemed to be a correlation between elevated temperatures of 180-190 degrees Celsius, a new group of solvents were selected based on their boiling points being above 190 degrees Celsius. The selected solvents were methyl 5-(dimethylamino)-2-methyl-5- oxopentanoate (pentanoic acid, bp. 263 degrees Celsius), 2-Hydroxy-/V,/V- dimethylpropanamide (A^/V-Dimethyllactamide, bp. 224 degrees Celsius), isosorbide dimethyl ether (bp. 236 degrees Celsius), l,3-Dioxolane-4-methanol (bp. 193 degrees Celsius), l,3-dioxane-5-ol (bp. 193 degrees Celsius), succinic acid dimethyl ester (bp. 196 degrees Celsius), succinic acid diethyl ester (bp. 217 degrees Celsius), dimethyl glutarate (bp. 216 degrees Celsius), glycerol diacetate, A/,A/-dimethyloctanamide (bp. 234 degrees Celsius), diethylglutarate (bp. 237 degrees Celsius), ethyl benzoate (bp. 212 degrees Celsius), 1,2-propanediol carbonate (propylene carbonate, bp. 240 degrees Celsius), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Polarclean, bp. 237 degrees Celsius), diethyl succinate (bp. 218 degrees Celsius), diethylene glycol monobutyl ether (bp. 228 degrees Celsius), diethyl adipate (bp. 251 degrees Celsius), benzyl alcohol (bp. 205 degrees Celsius), butyl benzoate (bp. 249 degrees Celsius), butyl 3- hydroxy butyrate (bp. 242 degrees Celsius), dipropylene glycol mono /V-butyl ether (bp. 237 degrees Celsius), dipropylene glycol (bp. 227 degrees Celsius), propylene glycol phenyl ether (bp. 243 degrees Celsius), 2-phenoxy ethanol (bp. 246 degrees Celsius), hexylene glycol (bp. 197 degrees Celsius), CH302C(CH2)nC02CH3 (n=2,3,4), and cyclademol (bp. 215 degrees Celsius). The solvents were to be tested at 150-190 degrees Celsius, and the temperature should be increased from 150 degrees Celsius to 190 degrees Celsius with 5-10 degrees Celsius increments. At the time of filing the present application, only the following of the further selected solvents had been tested: Methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (pentanoic acid, bp. 263 degrees Celsius), 2-Hydroxy-/V,/\/-dimethylpropanamide (N,N- Dimethyllactamide, bp. 224 degrees Celsius), isosorbide dimethyl ether (bp. 236 degrees Celsius), l,3-Dioxolane-4-methanol (bp. 193 degrees Celsius), l,3-dioxane-5-ol (bp. 193 degrees Celsius), succinic acid dimethyl ester (bp. 196 degrees Celsius), succinic acid diethyl ester (bp. 217 degrees Celsius), dimethyl glutarate (bp. 216 degrees Celsius), glycerol diacetate, A/,A/-dimethyloctanamide (bp. 234 degrees Celsius), diethylglutarate (bp. 237 degrees Celsius), ethyl benzoate (bp. 212 degrees Celsius), 1,2-propanediol carbonate (propylene carbonate, bp. 240 degrees Celsius), methyl 5-(dimethylamino)-2- methyl-5-oxopentanoate (Polarclean, bp. 237 degrees Celsius), diethyl succinate (bp. 218 degrees Celsius), and dipropylene glycol (bp. 227 degrees Celsius).
Most of the solvents showed to work, but surprisingly, succinic acid diethyl ester (bp. 217 degrees Celsius) and dipropylene glycol (bp. 227 degrees Celsius) did not work but showed
to work as the liquid decolorizing agent. Both solvents have similar chemical structure to some of the other solvents that did work. None of the solvents worked below 170 degrees Celsius, a few worked at 170 degrees Celsius, and the majority worked at 180-190 degrees Celsius.
Hence, diethylene glycol monobutyl ether (bp. 228 degrees Celsius), diethyl adipate (bp. 251 degrees Celsius), benzyl alcohol (bp. 205 degrees Celsius), butyl benzoate (bp. 249 degrees Celsius), butyl 3-hydroxybutyrate (bp. 242 degrees Celsius), dipropylene glycol mono /V-butyl ether (bp. 237 degrees Celsius), propylene glycol phenyl ether (bp. 243 degrees Celsius), 2-phenoxy ethanol (bp. 246 degrees Celsius), hexylene glycol (bp. 197 degrees Celsius), CH302C(CH2)nC02CH3 (n=2,3,4), and cyclademol (bp. 215 degrees Celsius) will be tested in the near future. These solvents are expected to work at 170-190 degrees Celsius, due to their chemical structures and boiling points, but some of them may surprisingly not work. These solvents are also thought to work as liquid decolorizing agents.
The experiments have been described with DMSO as the liquid decolorizing agent.
However, the following list of solvents also proved useful as the liquid decolorizing agent: dihydrolevoglucosenone, dimethyl sulfoxide, methyl-sulfonyl-methane, sulfolane, 4- valerolactone, 6-hexanolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, 2- Hydroxy-/\/,/\/-dimethylpropanamide, isosorbide dimethyl ether, l,3-Dioxolane-4-methanol, l,3-dioxane-5-ol, succinic acid dimethyl ester, glycerol diacetate, N,N- dimethyloctanamide, diethylglutarate, ethyl benzoate, 1,2-propanediol carbonate, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, dipropylene glycol, and succinic acid diethyl ester.
3) In another example, a textile blend of 65% polyester and 35% cotton was cut into lxl cm scrap pieces. 6.79g of the scraps was treated in 1M H2S0 from Supelco®, purchased from Sigma Aldrich, at 60 degrees Celsius for 30 minutes at a concentration of 2 wt% textile material. The treatment was done in a 1 L bluecap flask in an oil bath, using a CASO TC 2100 THERMO CONTROL INDUCTION HUB for temperature control and a stainless-steel stirrer, at 200 rpm. The sample was drained in a kitchen sieve and lightly washed in demineralized water, before transferring it to another bluecap flask with a 10% NaOH solution, containing 48 mg/kg anhydrous ethylenediaminetetraacetic acid (EDTA) from Sigma Aldrich. The sample was heated to 70 degrees Celsius in the oil bath and stirred for 30 minutes. The sample was washed in demineralized water and dried in a Coop mini oven at 150 °C for an hour. Then, it was transferred to a bluecap bottle with dimethyl sulfoxide >=99% (DMSO) from Sigma Aldrich, at a fibre concentration of 5wt% and "flash" heated to 150 °C three times within 30 minutes, with intermediate cooling to around 80-90
degrees Celsius. Two solvent exchanges were made, and the flash heating procedure was repeated both times, each time creating a decreasingly coloured fraction of used solvent.
Decoloured samples prepared from the method above were transferred to bluecap flasks, and the solvents that showed to work in the above examples were tested for their properties to dissolve the polyester fraction of the samples.
The solvent was added to obtain a concentration of 5wt% fibre material. The bluecap flasks were heated in an oil bath using a CASO TC 2100 THERMO CONTROL INDUCTION HUB for temperature control and a stainless-steel stirrer, at 200 rpm, and their content was stirred for 30 minutes. The remaining solid fraction (cellulosic filter cake) was separated from the soluble fraction (still relatively warm) by filtration (e.g., using a Buchner funnel and a vacuum pump), weighed, and compared with the initial weight of the decoloured fibre material.
The cellulosic filter cake was washed and dried, and the polyester containing solvent filtrate was collected in a bluecap flask and cooled with gentle shaking the closed bottle under lukewarm tap water. This resulted in polyester being crystallized into small white particles, that was filtered in the Buchner funnel, washed in demineralized water, and dried in a stink cabinet for 24h. All experiments resulted in a white polyester powder, and a cellulosic material.
Hence, the experiments showed that polyester can be separated from cotton fibres in mixed fabrics by the method of the present invention.
4) In another example, a textile blend of 65% polyester and 35% cotton was cut into lxl cm scrap pieces. 6.79 gram of the scraps were treated in 1M H2S0 from Supelco®, purchased from Sigma Aldrich, at 60 degrees Celsius for 30 minutes at a concentration of 2 wt% textile material. The treatment was done in a 1 L bluecap flask in an oil bath, using a CASO TC 2100 THERMO CONTROL INDUCTION HUB for temperature control and a stainless-steel stirrer, at 200 rpm. The sample was drained in a kitchen sieve and lightly washed in demineralized water, before transferring it to another bluecap flask with a 10% NaOH solution, containing 48 mg/kg anhydrous ethylenediaminetetraacetic acid (EDTA) from Sigma Aldrich. The sample was heated to 70 °C in the oil bath and stirred for 30 minutes. The sample was washed in demineralized water and dried in a Coop mini oven at 150 °C for an hour. Then, it was transferred to a bluecap bottle with dimethyl sulfoxide >=99% (DMSO) from Sigma Aldrich, at a fibre concentration of 5wt% and "flash" heated to 150 °C three times within 30 minutes, with intermediate cooling to around 80-90 °C.
Two solvent exchanges were made, and the flash heating procedure was repeated both times, each time creating a decreasingly coloured fraction of used solvent. Then the
sample was transferred to another bluecap flask, and DMSO was added for a concentration of 5wt% fibre material and heated to 180 °C for 30 minutes. The warm sample was filtered using a Buchner funnel and vacuum pump, and the solid, cellulosic filter cake was washed and dried, and the polyester containing DMSO filtrate was collected in a bluecap flask and cooled with gentle shaking the closed bottle under lukewarm tap water. This resulted in polyester being crystallized into small white particles, that was filtered in the Buchner funnel, washed in demineralized water, and dried in a stink cabinet for 24h. The result was 3.40 g of white polyester powder, and 1.88 g of cellulosic material, of which the latter was analysed to having an ion content (ISO/IEC 17025:2017) of; Mg: 31 mg/kg (ICP/MS), Mn: 0.61 mg/kg (ICP/MS), Co: Below detection limit of 0.1 mg/kg (ICP/MS) and Cu: 1.4 mg/kg.
5) In yet another example a sample of 6.18 gram pure cotton denim fabric was cut into lxl cm scrap pieces and treated in 1M H2S0 from Supelco®, purchased from Sigma Aldrich, at 60 °C for 30 minutes at a concentration of 5 wt% textile material. The treatment was done in a 1 L bluecap flask in an oil bath, using a CASO TC 2100 THERMO CONTROL INDUCTION HUB for temperature control and a stainless-steel stirrer, at 200 rpm. The sample was drained in a kitchen sieve and washed in demineralized water, dried in a Coop mini oven for 3 hours, before treating the sample for 30 minutes in a solution of 150 °C of DMSO2(20wt%)/DMSO. The DMS02 was purchased from www. contact- saddle. com. The solvent was changed once in this time, at the same concentration. Then, the samples were collected and transferred to a solution of DMSO2(20wt%)/DMSO, and treated at 175 °C for 25 minutes, before they were washed and dried. The result was intact pieces, with a total mass of 5.51 g of cellulosic material, with an ion content (ISO/IEC 17025:2017) of; Mg: 23 mg/kg (ICP/MS), Mn: 0.39 mg/kg (ICP/MS), Co: Below detection limit of 0.1 mg/kg (ICP/MS) and Cu: 1.7 mg/kg.
Claims
1. A process for providing a solid polyester fraction from a textile product comprising natural fibres, and polyester fibres, the process comprising the steps of:
(i) proving the textile product comprising natural fibres, and polyester fibres;
(ii) adding a liquid decolorizing agent to the textile product, thereby providing a decolorized first solid fraction and a first liquid fraction;
(ill) separating the first solid fraction from the first liquid fraction;
(iv) adding a solvent to the first solid fraction and heating the mixture at a temperature between 170-190 degrees Celsius, preferably within the range of 175-185 degrees Celsius, even more preferably at about 180 degrees Celsius, thereby providing a second solid fraction comprising the natural fibres, and a second liquid fraction comprising polyester;
(v) separating the second liquid fraction from the second solid fraction; and (vi) separating the polyester fraction from the second liquid fraction, thereby providing a solid polyester fraction.
2. The process according to claim 1, wherein the solvent is selected from the group consisting of dihydrolevoglucosenone, dimethyl sulfoxide, methyl-sulfonyl-methane, sulfolane, 4-valerolactone, 6-hexanolactone, methyl 5-(dimethylamino)-2-methyl-5- oxopentanoate, 2-Hydroxy-/V,/\/-dimethylpropanamide, isosorbide dimethyl ether, 1,3- Dioxolane-4-methanol, l,3-dioxane-5-ol, succinic acid dimethyl ester, glycerol diacetate, A/,A/-dimethyloctanamide, diethylglutarate, ethyl benzoate, 1,2-propanediol carbonate, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, diethylene glycol monobutyl ether, diethyl adipate, benzyl alcohol, butyl benzoate, butyl 3-hydroxybutyrate, dipropylene glycol mono /V-butyl ether, dipropylene glycol, propylene glycol phenyl ether, 2-phenoxy ethanol, hexylene glycol, cyclademol, CH302C(CH2)nC02CH3, where n=2, 3, or 4, or a combination thereof.
3. The process according to anyone of the claims 1-2, wherein the polyester fibres are polyethylene terephthalate fibres.
4. The process according to anyone of the claims 1-3, wherein the decolorization performed in step (ii) is performed at a temperature within the range of 130-165 degrees Celsius, such as in the range of 140-160 degrees Celsius, e.g., about 150 degrees Celsius.
5. The process according to anyone of the claims 1-4, wherein the solvent and the liquid decolorizing agent are the same.
6. The process according to anyone of the claims 1-5, wherein the mixture in step (iv) is heated at a temperature between 175-185 degrees Celsius.
7. The process according to anyone of the claims 1-6, wherein the liquid decolorizing agent is dimethyl sulfoxide (DMSO).
8. The process according to anyone of the claims 1-7, wherein the textile product comprises cellulosic fabrics, and polyester fibres.
9. The process according to anyone of the claims 1-8, wherein the wherein the liquid decolorizing agent is selected from the group consisting of dihydrolevoglucosenone, dimethyl sulfoxide, methyl-sulfonyl-methane, sulfolane, 4-valerolactone, 6-hexanolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, 2-Hydroxy-A/,/V- dimethylpropanamide, isosorbide dimethyl ether, l,3-Dioxolane-4-methanol, 1,3-dioxane- 5-ol, succinic acid dimethyl ester, glycerol diacetate, A/,A/-dimethyloctanamide, diethylglutarate, ethyl benzoate, 1,2-propanediol carbonate, methyl 5-(dimethylamino)-2- methyl-5-oxopentanoate, diethylene glycol monobutyl ether, diethyl adipate, benzyl alcohol, butyl benzoate, butyl 3-hydroxybutyrate, dipropylene glycol mono /V-butyl ether, dipropylene glycol, propylene glycol phenyl ether, 2-phenoxy ethanol, hexylene glycol, cyclademol, CH302C(CH2)nC02CH3, where n=2, 3, or 4, succinic acid diethyl ester, or a combination thereof.
10. The process according to anyone of the claims 1-9, wherein the textile product comprising a natural fibre and polyester fibres is subjected to a pre-treatment before adding a liquid decolorizing agent to the textile product in step (ii).
11. The process according to claim 10, wherein the pre-treatment comprises one, two or three steps selected from:
(a) an acidic treatment;
(b) an alkaline treatment;
(c) a hydrogen peroxide;
(d) or a combination of (a), (b) and (c).
12. The process according to claim 10, wherein the pre-treatment comprises: an acidic pre-treatment; or - an acidic pre-treatment and an alkaline pre-treatment; or an acidic pre-treatment and an alkaline pre-treatment and a hydrogen peroxide pre-treatment; or an alkaline pre-treatment; or an alkaline pre-treatment and a hydrogen peroxide pre-treatment; or a hydrogen peroxide pre-treatment.
13. The process according to anyone of the claims 10-12, wherein pre-treatment is performed at a temperature within the range of 20-95 degrees Celsius, such as within the range of 30-85°C, e.g., within the range of 40-75°C, such as within the range of 50-65°C, e.g., about 60 degrees Celsius.
14. A solid polyester fraction produced by the process according to any one of the claims 1-13.
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| WO2023072936A1 (en) * | 2021-10-29 | 2023-05-04 | Textile Change Aps | A process for decolouring textiles |
| CN116102782A (en) * | 2023-02-24 | 2023-05-12 | 西湖大学 | Recovery processing method of PET plastic waste, regenerated PET plastic and application |
| WO2023143943A1 (en) * | 2022-01-28 | 2023-08-03 | Textile Change Aps | A process for decolouring textiles |
| WO2023187053A1 (en) * | 2022-03-31 | 2023-10-05 | Basf Se | Separation of a polymer blend comprising a polyester by a solvent-based method |
| WO2024191649A1 (en) * | 2023-03-10 | 2024-09-19 | Solutia Inc. | A method of recycling poly(vinyl butyral) from multilayer poly(vinyl butyral) sheets as well as poly(vinyl butyral) sheets and laminated glass |
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| WO2023072936A1 (en) * | 2021-10-29 | 2023-05-04 | Textile Change Aps | A process for decolouring textiles |
| WO2023143943A1 (en) * | 2022-01-28 | 2023-08-03 | Textile Change Aps | A process for decolouring textiles |
| WO2023187053A1 (en) * | 2022-03-31 | 2023-10-05 | Basf Se | Separation of a polymer blend comprising a polyester by a solvent-based method |
| CN116102782A (en) * | 2023-02-24 | 2023-05-12 | 西湖大学 | Recovery processing method of PET plastic waste, regenerated PET plastic and application |
| WO2024191649A1 (en) * | 2023-03-10 | 2024-09-19 | Solutia Inc. | A method of recycling poly(vinyl butyral) from multilayer poly(vinyl butyral) sheets as well as poly(vinyl butyral) sheets and laminated glass |
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