Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
  • D06M13/184—Carboxylic acids; Anhydrides, halides or salts thereof
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
  • D01F2/06—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from viscose
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
  • D06M11/07—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with halogens; with halogen acids or salts thereof; with oxides or oxyacids of halogens or salts thereof
  • D06M11/11—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with halogens; with halogen acids or salts thereof; with oxides or oxyacids of halogens or salts thereof with halogen acids or salts thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
  • D06M11/32—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond
  • D06M11/34—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond with oxygen, ozone or ozonides
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
  • D06M11/32—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond
  • D06M11/50—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond with hydrogen peroxide or peroxides of metals; with persulfuric, permanganic, pernitric, percarbonic acids or their salts
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C3/00—Pulping cellulose-containing materials
  • D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/10—Bleaching ; Apparatus therefor
  • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
  • D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/10—Bleaching ; Apparatus therefor
  • D21C9/16—Bleaching ; Apparatus therefor with per compounds
  • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
  • D21H13/02—Synthetic cellulose fibres
  • D21H13/08—Synthetic cellulose fibres from regenerated cellulose
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D1/00—Treatment of filament-forming or like material
  • D01D1/02—Preparation of spinning solutions
• • 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
  • D06L4/50—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs by irradiation or ozonisation
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
  • D06M13/184—Carboxylic acids; Anhydrides, halides or salts thereof
  • D06M13/188—Monocarboxylic acids; Anhydrides, halides or salts thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
  • D06M13/184—Carboxylic acids; Anhydrides, halides or salts thereof
  • D06M13/207—Substituted carboxylic acids, e.g. by hydroxy or keto groups; Anhydrides, halides or salts thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
  • D06M2101/02—Natural fibres, other than mineral fibres
  • D06M2101/04—Vegetal fibres
  • D06M2101/06—Vegetal fibres cellulosic

Definitions

• the invention relates to a one-stage step in a process for regenerating reclaimed cellulose, where acid metal removal is combined together with acid oxidative bleach in one single stage.
• WO 2012/057684 discloses a process for the derivatization of cellulose comprising the sequential steps: a) mixing cellulose with a viscosity below 900 ml/g with an aqueous solution to obtain a liquid, wherein particles comprising cellulose in said liquid have a diameter of maximum 200 nm, wherein the temperature of the aqueous solution is below 20° C., and wherein the pH of the aqueous solution is above 12, b) subjecting the liquid to at least one of the steps: i) decreasing the pH of the liquid with at least 1 pH unit, ii) increasing the temperature by at least 20° C., and c) derivatization of the cellulose.
• WO 2010/124944 discloses a process for the hydrolysis of cellulose comprising the sequential steps (a) mixing cellulose with a viscosity below 900 ml/g with an aqueous solution to obtain a liquid, wherein particles comprising cellulose in said liquid have a diameter of maximum 200 nm, wherein the temperature of the aqueous solution is below 35° C., and wherein the pH of the aqueous solution is above 12, (b) subjecting the liquid to at least one of the steps: (i) decreasing the pH of the liquid with at least 1 pH unit and (ii) increasing the temperature by at least 20° C., and (c) hydrolysing the cellulose.
• glucose manufactured according to the method and ethanol manufactured from the glucose.
• WO 2013/124265 discloses a method for regeneration of a cellulose containing material, comprises the steps: a) exposing the cellulose containing material to oxygen with an alkali aqueous solution at a pH of at least 9, and a temperature of at least 20° C., b) dispersing the cellulose containing material in the alkali aqueous solution, wherein the temperature of the alkali aqueous solution is lowered below 15° C., and wherein the pH of the alkali aqueous solution is above 9, c) adding an organic solvent to the dispersion to precipitate cellulose, and d) separating the precipitated cellulose by at least one method selected from filtering and centrifugation.
• the method makes it possible to maintain a high alkali pH value in the process, which saves costs since the pH value does not have to be lowered by additions of various additives.
• WO 2018/104330 discloses a cellulose based fibre made of i) a cellulose dissolving pulp, and ii) a recycled cellulose textile, which is treated to swell the cellulose with a reducing additive and a) bleached with oxygen at alkaline conditions with a pH in the range 9-13.5 and/or b) bleached with ozone at acid conditions below pH 6, wherein the cellulose based fibre is manufactured with one selected from a Viscose process and a Lyocell process.
• WO 2018/073177 discloses method for recycling textiles comprising cellulose with the following steps of:
• WO 2015/077807 discloses a process for pretreating reclaimed cellulose fibres to be used in the production of moulded bodies from regenerated cellulose by the Viscose or Lyocell process, wherein the treatment of the reclaimed cellulose fibres includes a chemical metal removing stage and an oxidative bleaching stage.
• the process is described as a multistage process.
• the metal removing stage can be acidic washing or treatment with a complexing agent, or a combination of both.
• the oxidative bleaching stage can be treatment with peroxide, oxygen or ozone.
• WO 2016/123643 discloses a process for producing a man-made cellulosic moulded body using a reclaimed man-made cellulosic raw material, including the steps of forming a cellulose solution by dissolution of cellulosic raw material, the extrusion of the cellulose solution obtained to form a moulded body, and coagulation and regeneration of the cellulose to obtain the man-made cellulosic moulded body, wherein the reclaimed man-made cellulosic raw material is mixed with a virgin cellulosic raw material prior to forming the cellulose solution.
• WO 2016/123643 discloses that an acidic washing step and a treatment with an aqueous solution of a complexing agent may be combined in one process step, by adding the complexing agent to the acidic washing liquor.
• problems in the state of the art include how to improve the reduction of metal content of regenerated cellulose. Another problem is how to further reduce the clogging properties of regenerated cellulose. In general, it is also desirable to provide a simpler and more efficient method to regenerate cellulose.
• a one-stage method is more efficient, faster and less costly compared to a multi-stage method according to the prior art.
• the invention makes it possible to remove metals efficiently without using complex formers such as EDTA, which may be an environmental issue due to the longevity of EDTA and similar compounds.
• reclaimed cellulose can be regenerated and used for production of moulded bodies.
• processes include but are not limited to: the Lyocell process, in particular using aqueous amine oxide, such as 4-methylmopholine N-oxide (EP 0356419 and EP 0584318), the viscose process (Kurt Götze, Chemiefasern nach dem Viskoseclar, 1967) and the Modal process (AT 287905).
• the inventors believe that the combination of acid oxidative bleaching and acid metal removal in one step can oxidize at least some of the chemical structures which bind the metals and thus facilitates the removal of the metals. Further the inventors believe that an additional effect may be that the oxidative bleaching give some degradation products, which in some cases may form complexes with the metal ions and thus also facilitate the removal of metal.
• Metal ions are present in recycled cellulose and it is desired to reduce the content of such metal ions.
• the stage is one single stage and is intended to be used as a stage in the regeneration of reclaimed cellulose, including recycled clothing, for instance clothing comprising cotton.
• the present stage according to the invention is to be carried out together with additional steps and stages in the regeneration of reclaimed cellulose. Additional stages are known in the art and can easily be combined with the stage according to the invention by a skilled person. A number of additional stages are suitably performed in the regeneration of reclaimed cellulose as described in the prior art. Buttons, zips and other objects of solid metal are in one embodiment removed before the stage.
• a mechanical treatment is in one embodiment, carried out before the present stage, such as for instance shredding and milling.
• a chemical treatment step is in one embodiment carried out before the stage according to the invention. Such a chemical treatment step may include a partial or entire dissolution of the reclaimed cellulose.
• a step of removing non-cellulosic fibres is performed.
• non-cellulosic include but are not limited to fibres comprising polyester, elastan, acryl.
• the removal of non-cellulosic fibres is carried out by flotation.
• any suitable acid can be used in order to obtain an acidic pH during the stage, i.e. a pH value below 7.
• mixtures of acids can be used.
• a carboxylic acid is present during the stage.
• the wording that an acid is present during the stage means that it may be present during at least a part of the stage, for instance an acid may be present at the beginning of the stage in order to create the desired pH value and during the stage one or more additional acids can be added.
• at least one or more acids are present during a part of the stage.
• an acid is present during a part of the stage, it should be ensured that the pH value is acidic as desired during the entire stage, for instance by presence of acid(s) also in the beginning of the stage.
• acids which may be present as only acids or together with other acids include but are not limited to hydrochloric acid, formic acid, citric acid, acetic acid. Mixtures including one or more of these acids are also encompassed. Mixture including these acids together with additional acids are also encompassed.
• at least one acid selected from the group consisting of hydrochloric acid, formic acid, citric acid, acetic acid and any mixture thereof, is present during the stage. In one embodiment, a mixture of acids is used.
• hydrochloric acid can be mixed with a weaker acid such as acetic acid in order to achieve the desired pH.
• a weaker acid such as acetic acid
• the fact that at least one acid is present during the stage means that the acid can be added in the beginning of the stage, or before the stage or a combination thereof. In one embodiment, the acid is added in the beginning of the stage. Addition of an acid in the beginning of the stage or before the stage does not exclude the possibility of addition of further acid during the stage.
• the pH is in the interval 1-3 during the stage. In another embodiment the pH is in the interval 2-3 during the stage. In an alternative embodiment, the pH is in the interval 0-4 during the stage. In yet another embodiment the pH is in the interval 1-5 during the stage. In a further embodiment, the pH is in the interval 1.5-5 during the stage. In a still further embodiment, the pH is in the interval 0-5 during the stage. In one embodiment the pH is in the interval 1.5-4.5.
• the temperature during the stage is in the interval 40-60° C. In another embodiment, the temperature during the stage is in the interval 30-75° C.
• the temperature during the stage can vary. For instance, the temperature can be high and in the upper part of the interval in the beginning of the stage and lower towards the end. Also a lower initial temperature followed by a rise in the temperature is conceivable. It is not necessary that the temperature is within the ranges during the entire stage, temperatures below and above the ranges are also conceivable. In alternative embodiments, the temperature is outside the ranges during the entire stage.
• At least one weak acid with a pKa above 3 and below 7 is present during the stage. 3 ⁇ pKa ⁇ 7.
• a weak acid has the advantage that the cellulose is not hydrolysed by the acid, or at least not hydrolysed to any significant degree.
• acetic acid is present during the stage.
• acetic acid is beneficial for removing dye.
• addition of acetic acid gives an improvement in the removal of certain dyes.
• the stage according to the present invention can suitably be combined with additional bleaching stages in order to fully remove any remaining dyes. Such additional bleaching stages are known and described in the prior art.
• sulphuric acid is not present during the stage.
• a common impurity in reclaimed cellulose such as reclaimed cotton is calcium.
• Ca 2+ ions can react with the sulphuric acid and form CaSO 4 (gypsum), which makes the process less efficient. It is still possible to use sulphuric acid as evidenced by the examples, but longer treatment time and/or a higher concentration of sulphuric acid would be necessary. Further less efficient metal removal can be expected. Thus the use of sulphuric acid is often less preferred.
• sulphuric acid is present during the stage. If used, sulphuric acid should be used at higher concentration and/or with longer treatment time.
• an acidic oxidative bleach takes place simultaneously in the same stage in order to improve the efficiency.
• hydrogen peroxide is present during the stage.
• the dose of hydrogen peroxide is in one embodiment 2 to 40 kg hydrogen peroxide per odtp.
• ozone is present during the stage.
• the dose of ozone is 0.1 to 6 kg ozone per odtp. Since the acidic metal removal and the acidic oxidative bleach are carried out together in the same stage, the pH is acidic for all conceivable oxidative bleaching additives.
• the oxidative bleaching agent is added before the step starts or at the start of the stage.
• an oxidative bleaching agent is added in the beginning of the stage and at least one oxidative bleaching agent is added during the stage.
• at least one oxidative bleaching agent is added in the beginning of the stage and at least one additional different oxidative bleaching agent is added during the stage.
• ozone is added in the beginning of the stage and hydrogen peroxide is added during the stage at a later point in time.
• hydrogen peroxide is added in the beginning of the stage and ozone is added during the stage. Also other combinations of additions of oxidative bleaching agents are encompassed.
• the stage with both acid metal removal and acid oxidative bleaching is the only acidic chemical metal removal step in the process. Even if the detailed mechanisms are not fully investigated the inventors believe that the acidic metal removal and the acidic oxidative bleach should be carried out together in one stage. If acidic metal removal and the bleach are carried out separately the efficiency is lower as seen in the examples.
• the combined acid metal removal and acid oxidative bleaching is in one embodiment the only chemical metal removal stage in the process, i.e. no additional acid chemical metal removal stages are carried out before or after the stage according to the invention.
• the metal removal according to the invention is so efficient that it is more economical to use only one efficient stage and no additional acidic metal removal stages.
• the acidic metal removal in the stage is the only acidic metal removal.
• the stage is carried out during a time in the interval from 1 to 120 minutes. In another embodiment the stage is carried out during at time in the interval 1-60 minutes. In yet another embodiment the stage is carried out during 2-60 minutes. In yet another embodiment the stage is carried out during 5-60 minutes. In yet another embodiment the stage is carried out during 10-60 minutes. Longer treatment times can also be used, but can also be less economical. Thus in one embodiment, the stage is carried out during a time of at least 1 minute, at least 2 minutes, at least 5 minutes, or at least 10 minutes.
• the reclaimed cellulose fibres are in one embodiment, cotton fibres.
• the cellulose fibres originate from pre-consumer cellulose containing waste such as cotton.
• Pre-consumer cellulose containing waste includes but is not limited to combing waste and cuttings.
• the cellulose fibres originate from post-consumer cellulose containing waste such as cotton.
• Post-consumer cellulose containing waste includes but is not limited to laundry waste and used clothes.
• the cellulose fibres comprise pulp prepared from cotton rags.
• the reclaimed cellulose is mechanically shredded or milled prior to the use.
• the production of moulded bodies is made with the Viscose process. In one embodiment, the production of moulded bodies is made with the Lyocell process. In one embodiment, the production of moulded bodies is made with the Modal process. These processes for production of moulded bodies are known in the art and can be performed by a skilled person.
• the intrinsic viscosity of the regenerated cellulose is suitably adjusted as needed and as known depending on the intended production process for the moulded bodies. For instance, for a Viscose process the intrinsic viscosity can be adjusted to a value in the range 350-650 ml/g. For instance, for a Lyocell process the intrinsic viscosity can be adjusted to 350-500 ml/g.
• Reactivity test based on wash, white jersey fabric.
• the samples were treated mechanically by cutting in pieces 1 ⁇ 1 cm and thereafter treated in a mixer for 40 seconds. This shredding served to open the fiber structure.
• the material was treated in a chemical step where the material was bleached at high pH, i.e. a pH above 7.
• the second wash was a different metal removal step.
• the samples were diluted to a concentration of 9 wt % and the pH was adjusted to 6 for all samples with NaOH and if needed with H 2 SO 4 .
• Reactivity test based on wash, white jersey fabric. First, the material was subjected to a mechanical step and thereafter in a chemical step, both as in example 1. Thereafter the following three samples were prepared.
• the samples were wetted overnight and diluted to a concentration of 3.5 wt %. Thereafter the pH value of each pulp sample was adjusted and H 2 O 2 was added.
• the samples had a dwell time of about 20 minutes before wash with deionized water. This gave a stage with combined acidic metal removal and acidic oxidative bleach. All samples were washed with 1.5 liters deionized water after filtering.
• the samples were diluted to a concentration of 9 wt % and the pH was adjusted to 6 for all samples with NaOH. If needed the pH was also adjusted with H 2 SO 4 for the H 2 SO 4 -sample and with HCl for the HCl-sample and the acetic acid-sample.
• the material was subjected to a step with combined acid metal removal and acid oxidative bleach.
• acetic acid was charged with 12 kg/odt and hydrogen peroxide was charged with 5 kg/odt.
• the pH was 2 and the temperature was 55° C.
• the treatment time was 20 minutes.
• the content of various metals was measured in the denim before the treatment and after the treatment. The measurement results are shown in the below table. The results are calculated as mg of metal per kg of material in dry state.
• Example 3 was repeated, but with different conditions. Acetic acid was charged with 18 kg/odt and hydrogen peroxide was charged with 2 kg/odt. The temperature was 35° C. The treatment time was 60 minutes. The example was repeated twice. Once with pH 3.5 and once with pH 2.5.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Paper (AREA)

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• 2020
  • 2020-03-16 EP EP20163367.4A patent/EP3882380B1/en active Active
• 2021
  • 2021-03-12 EP EP21710332.4A patent/EP4121584A1/en active Pending
  • 2021-03-12 WO PCT/EP2021/056406 patent/WO2021185704A1/en unknown
  • 2021-03-12 CN CN202180018730.2A patent/CN115210417A/zh active Pending
  • 2021-03-21 US US17/909,165 patent/US20230146394A1/en active Pending

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