WO2017039615A1 - Improving the purity of materials recycled from disposable absorbent articles - Google Patents
Improving the purity of materials recycled from disposable absorbent articles Download PDFInfo
- Publication number
- WO2017039615A1 WO2017039615A1 PCT/US2015/047736 US2015047736W WO2017039615A1 WO 2017039615 A1 WO2017039615 A1 WO 2017039615A1 US 2015047736 W US2015047736 W US 2015047736W WO 2017039615 A1 WO2017039615 A1 WO 2017039615A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- disposable absorbent
- absorbent article
- superabsorbent polymer
- stream
- cellulosic fiber
- Prior art date
Links
- 230000002745 absorbent Effects 0.000 title claims abstract description 99
- 239000002250 absorbent Substances 0.000 title claims abstract description 99
- 239000000463 material Substances 0.000 title claims abstract description 83
- 229920000247 superabsorbent polymer Polymers 0.000 claims abstract description 101
- 239000000835 fiber Substances 0.000 claims abstract description 87
- 238000000034 method Methods 0.000 claims abstract description 69
- 239000004583 superabsorbent polymers (SAPs) Substances 0.000 claims abstract description 56
- 239000013535 sea water Substances 0.000 claims abstract description 34
- 108090000790 Enzymes Proteins 0.000 claims abstract description 22
- 102000004190 Enzymes Human genes 0.000 claims abstract description 22
- 238000004064 recycling Methods 0.000 claims abstract description 20
- 238000012545 processing Methods 0.000 claims abstract description 16
- 239000000203 mixture Substances 0.000 claims abstract description 14
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims abstract description 13
- 239000001110 calcium chloride Substances 0.000 claims abstract description 13
- 229910001628 calcium chloride Inorganic materials 0.000 claims abstract description 13
- 239000012530 fluid Substances 0.000 claims abstract description 13
- 238000004537 pulping Methods 0.000 claims abstract description 13
- 238000011084 recovery Methods 0.000 claims abstract description 12
- 206010015137 Eructation Diseases 0.000 claims abstract description 10
- 208000027687 belching Diseases 0.000 claims abstract description 10
- 229940088598 enzyme Drugs 0.000 claims description 21
- 108010059892 Cellulase Proteins 0.000 claims description 10
- 229940106157 cellulase Drugs 0.000 claims description 10
- 239000002861 polymer material Substances 0.000 description 16
- 230000008569 process Effects 0.000 description 13
- 239000001913 cellulose Substances 0.000 description 11
- 229920002678 cellulose Polymers 0.000 description 11
- 229920000642 polymer Polymers 0.000 description 8
- 239000000470 constituent Substances 0.000 description 7
- 239000010800 human waste Substances 0.000 description 7
- 239000004033 plastic Substances 0.000 description 7
- 229920003023 plastic Polymers 0.000 description 7
- 239000007864 aqueous solution Substances 0.000 description 6
- 238000012216 screening Methods 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 210000002700 urine Anatomy 0.000 description 6
- 239000000243 solution Substances 0.000 description 5
- 239000004743 Polypropylene Substances 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 230000018044 dehydration Effects 0.000 description 4
- 238000006297 dehydration reaction Methods 0.000 description 4
- -1 polypropylene Polymers 0.000 description 4
- 229920001155 polypropylene Polymers 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 229910001415 sodium ion Inorganic materials 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- 239000004698 Polyethylene Substances 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 150000007513 acids Chemical class 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000003204 osmotic effect Effects 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- 229910001420 alkaline earth metal ion Inorganic materials 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 230000002255 enzymatic effect Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 235000019645 odor Nutrition 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 229920002994 synthetic fiber Polymers 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 206010021639 Incontinence Diseases 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000006911 enzymatic reaction Methods 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000002504 physiological saline solution Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 238000012549 training Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/80—Destroying solid waste or transforming solid waste into something useful or harmless involving an extraction step
-
- 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
- B29B17/04—Disintegrating plastics, e.g. by milling
-
- 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
-
- 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
- B29B2017/0217—Mechanical separating techniques; devices therefor
- B29B2017/0251—Hydropulping for converting the material under the influence of water into a slurry, e.g. for separating laminated plastic from paper
-
- 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
- B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
- B29K2001/08—Cellulose derivatives
-
- 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
- B29L2031/48—Wearing apparel
- B29L2031/4871—Underwear
- B29L2031/4878—Diapers, napkins
-
- 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
- C08J2300/00—Characterised by the use of unspecified polymers
- C08J2300/14—Water soluble or water swellable polymers, e.g. aqueous gels
-
- 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 disclosure relates to methods for improving the purity and quantity of materials, including synthetic materials, recovered from recycling disposable absorbent articles. More specifically, the present disclosure relates to methods for easily and economically separating the materials in a disposable absorbent article, removing fluid absorbed by superabsorbent polymers (SAP), and recovering the constituent materials such as polymer, cellulosic fibers, and superabsorbent polymer.
- SAP superabsorbent polymers
- disposable absorbent articles such as baby diapers, consist of polypropylene (PP), polyethylene (PE), superabsorbent polymer (SAP), cellulose pulp, and the like.
- the present disclosure presents a means to solve the problems of conventional techniques as described above, including methods for economically and easily removing moisture absorbed by a superabsorbent polymer, capable of absorbing an amount of moisture equivalent to a hundred times its own weight, once it has been used for its intended purpose.
- the present disclosure provides a method for improving the recovery from recycling a disposable absorbent article including superabsorbent polymer, the method including separating the article into a mixed polymeric material/cellulosic fiber stream and a superabsorbent polymer/fibers stream; and processing the mixed polymeric
- the present disclosure also provides a method for improving the recovery from recycling a disposable absorbent article including superabsorbent polymer, the method including shredding the disposable absorbent article; re-pulping the shredded disposable absorbent article; and dehydrating the superabsorbent polymer, wherein dehydrating includes belching fluid from swollen superabsorbent polymers (SAPs) by immersing swollen SAP in a gel state into a composition for removing moisture, wherein seawater and 0.5 to 3% by weight of calcium chloride based on the weight of seawater are mixed for 10 minutes to 4 hours.
- the method also includes separating the pulped and shredded disposable absorbent article into a mixed polymeric material/cellulosic fiber stream and a
- the present disclosure further provides a method for improving the recovery from recycling a disposable absorbent article including superabsorbent polymer, the method including shredding the disposable absorbent article; re-pulping the shredded disposable absorbent article; and dehydrating the superabsorbent polymer.
- the method also includes separating the pulped and shredded disposable absorbent article into a mixed polymeric material/cellulosic fiber stream and a superabsorbent polymer/fibers stream; processing the mixed polymeric material/cellulosic fiber stream using an enzyme to release the cellulosic fibers from the polymeric materials, wherein the enzyme is cellulase; and transferring cellulosic fiber separated from the mixed polymeric material/cellulosic fiber stream to the superabsorbent polymer/fibers stream.
- the methods of the present application can be advantageously used for recycling disposable absorbent articles including an absorbent consisting of superabsorbent polymer and cellulose pulp, which have been difficult to isolate into individual resources by means of conventional chemical processes after being used for human waste purposes.
- Fig. 1 is a flowchart illustrating the material recovery methods described herein.
- the present disclosure relates to methods for improving the purity and quantity of materials, including synthetic materials, recovered from recycling disposable absorbent articles.
- the present disclosure relates to methods for easily and economically separating the materials in a disposable absorbent article, removing fluid absorbed by superabsorbent polymers (SAP), and recovering the constituent materials such as polymer, cellulosic fibers, and superabsorbent polymer.
- SAP superabsorbent polymers
- the objective of the recycling process is to create clean streams of recovered fiber, plastics, and SAP.
- the residual fibers need to be removed from the plastics stream to be considered a "clean" stream of recovered plastic.
- superabsorbent polymers To isolate such superabsorbent polymers in a gel state and cellulose pulp into individual resources, superabsorbent polymers must be converted from a gel state to the original particle or other state by removing moisture absorbed by superabsorbent polymers.
- Disposable absorbent articles including baby diapers generally consist of lining, absorbent transport layer, absorbent material, waterproof film, leg and waist bands, and the like.
- diapers In addition to diapers, diaper pants, training pants, youth pants, incontinence articles, feminine care products, and other disposable absorbent articles can include similar structures.
- the absorbent material includes superabsorbent polymer material and cellulose pulp. The functions and actions of each constituent are briefly described below.
- the lining directly contacts a user's skin, and is designed to pass human waste toward the absorbent while keeping dry the surface contacting the user's skin.
- the absorbent transport layer if present, aids in both passing the waste to the absorbent material and preventing the waste from returning back to the lining.
- the absorbent material usually includes cellulose pulp and superabsorbent polymer, which is typically capable of absorbing an amount of moisture equivalent to a hundred times its own weight.
- the absorbent material can be covered by polypropylene nonwoven fabrics or other suitable material to help maintain its shape.
- a waterproof film backsheet or outer cover acts to protect clothing and surfaces by preventing waste from leaving the article.
- a waist band and leg bands if present, help to prevent waste from leaving the article by providing seals at the edges of the articles.
- Each structure can be affixed to other structures via physical or chemical bonding means.
- a disposable absorbent article is first shredded using conventional means.
- shredding a disposable absorbent article to a size less than approximately 21 cm by 21 cm, or preferably less than approximately 12 cm by 12 cm, or more preferably less than approximately 6 cm by 6 cm produced the best results, but this can vary by product and material type.
- the shredded disposable absorbent article is then re-pulped or re-slushed in an aqueous solution to assist in separating the materials.
- pulping to a consistency less than 5-6% with a retention time of 60 minutes at a temperature between 30 and 40 °C produced the best results, but this can vary by product and material type.
- Each material of the disposable absorbent article such as
- pulp/cellulose, mixed plastic, and SAP is efficiently separated under the proper separation condition such as shredding size, consistency, time, and temperature in pulping system.
- moisture absorbed by polymer materials can be expelled when a new outer environment is created by incorporating a solution for removing moisture that was absorbed in the superabsorbent polymer materials to create an outward osmotic flow from the inside of the polymer materials or to lower the repulsion between molecular chains in the polymer material.
- superabsorbent polymer materials are conventionally obtained by polymerization of acrylic acid and sodium hydroxide, a sodium ion is contained in superabsorbent polymer molecules. Further, when contacted with moisture including human waste such as urine, artificial urine, or water, sodium ions in the polymer molecules readily dissociate to form a concentration gradient between the inside and outside of the polymer materials, thereby causing an inflow of moisture from outside the polymer materials. On the other hand, if relatively higher concentrations of sodium ions are provided outside the polymer materials, counter-flow is created to belch moisture absorbed by the polymer materials.
- intermolecular repulsion between superabsorbent polymer materials is induced by negative charges generated by oxidation of sodium ions included within the polymer molecules, and if an oxidant (e.g., a divalent metal cation) that weakens the repulsion between negative charges is present, the repulsion is weakened to decrease the distance between the molecular chains of the polymers. As a result, the space for retaining moisture becomes narrower such that moisture absorbed in the polymer materials is discharged.
- an oxidant e.g., a divalent metal cation
- SAPs Superabsorbent polymers
- SAPs are not particularly limited, but any SAPs generally used in disposable absorbent articles can be used. Further, SAPs are commercially available.
- swollen superabsorbent polymers in a gel state refer to
- conditions similar to those found in the use of absorbent articles can be obtained by allowing SAPs to absorb moisture such as artificial urine, i.e. , 0.9% by weight aqueous NaCI solution (otherwise known as "physiological saline”) that is similar to human urine, or urine as real human waste, or distilled water.
- aqueous NaCI solution otherwise known as "physiological saline”
- seawater in the composition for removing moisture that is used for belching fluid from swollen superabsorbent polymers in a gel state natural seawater can be used directly without undergoing further processing or purification, or artificial seawater having a similar composition to that of seawater can be purchased or prepared for use.
- Seawater that can be used in the present disclosure can have a salinity (%) of 2.0 to 4.0%, and comprise 1 .5 to 3.1 % by weight of sodium chloride and 0.4 to 0.8% by weight of alkaline earth metal ions, such as Mg 2+ and Ca 2+ . Accordingly, based on seawater having a salinity of 3.5%, seawater comprises about 2.7% by weight of sodium chloride, which is about three times of the salinity of urine (0.9% by weight), and thus, if swollen SAPs in a gel state are immersed into an aqueous solution containing seawater, the solution serves to generate an osmotic flow from the inside to the outside of the SAP materials.
- alkaline earth metal ions such as Mg 2+ and Ca 2+ , contained in seawater interact with an anion within the swollen SAP materials in a gel state to lower the repulsion between SAP molecules.
- the effect of expelling moisture absorbed by the SAPs outside the molecules is further increased.
- Calcium chloride used in a composition for removing moisture according to the present disclosure is easy to handle, readily available at low cost, has little toxicity or odor, and primarily exist as ions in an aqueous solution due to its very high degree of ionization.
- Commercially available calcium chloride having a purity of 74 to 99% by weight can be used as is without purification.
- the aqueous solution containing seawater and calcium chloride can have a pH in a range of 7.0 to 8.0, which is desirable because the efficiency of belching fluid from swollen superabsorbent polymers in a gel state is high within this range.
- the mixture is separated into two streams using a screen system employing fingers, bars, or any other suitable screen system.
- the mixture is separated into a plastic- rich stock including primarily polymer materials with fibers adhesively attached, and fiber- and SAP-rich stock including primarily free fibers and dehydrated SAP. If used disposable absorbent articles are being processed, any human waste present in the original articles can also be removed from the streams at this or any suitable point and sent to wastewater treatment for further processing (not shown).
- the plastic rich stock or mixed polymeric material/cellulosic fiber stream is further refined using, for example, a drum screen. Free fibers are returned to the previous separation screen to be entrained in the superabsorbent polymer/fibers stream.
- the remainder of the mixed polymeric material/cellulosic fiber stream is treated with an enzyme to release the fibers from the polymeric material.
- an enzyme to release the fibers from the polymeric material.
- any suitable enzyme can be used, environmentally-friendly cellulase is preferred.
- An additional screening following the enzymatic treatment using a drum screen or any other suitable screen separates the remaining free fibers and returns them to the superabsorbent polymer/fibers stream.
- the remainder of what was initially the mixed polymeric material/cellulosic fiber stream is almost entirely polymeric material.
- This output material can also be sterilized by heating or any suitable method (not shown), particularly if the source articles are used disposable absorbent articles. Experimentation showed that such treatment with cellulase following the separation, dehydration, and screening processes improves the purity of the final polymer stream from 6.2% residual fibers to 0.1 % residual fiber, yielding essentially pure plastic for future use.
- the superabsorbent polymer/fibers stream is then screened using a slot screen or any other suitable screening method to remove dehydrated SAP.
- the superabsorbent polymer/fibers stream is then sent through a cleaner that removes virtually all of the remaining dehydrated SAP, which is added to the SAP removed in the previous screening step.
- the two SAP streams are combined to output a stream of dehydrated SAP for future use.
- This output material can also be sterilized by heating or any suitable method (not shown), particularly if the source articles are used disposable absorbent articles.
- the remainder of what was initially the superabsorbent polymer/fibers stream is almost entirely fiber material, with the result being a stream of essentially pure fiber for future use.
- the methods according to the present disclosure can be advantageously used as an environmentally-friendly and economical means to recycle disposable absorbent articles such as diapers that include an absorbent core having SAP and cellulose pulp, even after the article has been used for absorption.
- a primary improvement in the process described herein over previous attempts is the dehydration and removal of SAP prior to the enzymatic treatment. Otherwise, the pH control of the enzyme reaction is very difficult due to the buffering effect from calcium- substituted SAP.
- An additional improvement is the use of an environmentally-friendly enzyme such as cellulase to release residual cellulosic fibers that are attached to synthetic polymeric (PE/PP plastics) materials.
- an environmentally-friendly enzyme such as cellulase to release residual cellulosic fibers that are attached to synthetic polymeric (PE/PP plastics) materials.
- the use of such enzymes displaces the use strong acids or other harsh chemicals to release residual fibers.
- a method for improving the recovery from recycling a disposable absorbent article including superabsorbent polymer includes separating the article into a mixed polymeric material/cellulosic fiber stream and a superabsorbent polymer/fibers stream; and processing the mixed polymeric material/cellulosic fiber stream using an enzyme to release the cellulosic fibers from the polymeric materials.
- a second particular aspect includes the first particular aspect, wherein the disposable absorbent article is a post-use absorbent article.
- a third particular aspect includes the first and/or second aspect, further including shredding the disposable absorbent article prior to separating.
- a fourth particular aspect includes one or more of aspects 1 -3, further comprising re- pulping the shredded disposable absorbent article.
- a fifth particular aspect includes one or more of aspects 1 -4, further comprising dehydrating the superabsorbent polymer.
- a sixth particular aspect includes one or more of aspects 1 -5, wherein dehydrating uses seawater or an ionic equivalent of seawater.
- a seventh particular aspect includes one or more of aspects 1 -6, wherein dehydrating includes belching fluid from swollen superabsorbent polymers (SAPs) by immersing swollen SAP in a gel state into a composition for removing moisture, wherein seawater and 0.5 to 3% by weight of calcium chloride based on the weight of seawater are mixed for 10 minutes to 4 hours.
- SAPs superabsorbent polymers
- An eighth particular aspect includes one or more of aspects 1 -7, wherein the enzyme is cellulase.
- a ninth particular aspect includes one or more of aspects 1 -8, wherein the disposable absorbent article is a diaper.
- a tenth particular aspect includes one or more of aspects 1 -9, further comprising transferring cellulosic fiber separated from the mixed polymeric material/cellulosic fiber stream to the superabsorbent polymer/fibers stream.
- An eleventh particular aspect includes one or more of aspects 1 -10, wherein the separating is performed before the processing.
- a method for improving the recovery from recycling a disposable absorbent article including superabsorbent polymer includes shredding the disposable absorbent article; re-pulping the shredded disposable absorbent article; and dehydrating the superabsorbent polymer, wherein dehydrating includes belching fluid from swollen superabsorbent polymers (SAPs) by immersing swollen SAP in a gel state into a composition for removing moisture, wherein seawater and 0.5 to 3% by weight of calcium chloride based on the weight of seawater are mixed for 10 minutes to 4 hours.
- SAPs swollen superabsorbent polymers
- the method also includes separating the pulped and shredded disposable absorbent article into a mixed polymeric material/cellulosic fiber stream and a superabsorbent polymer/fibers stream; and processing the mixed polymeric material/cellulosic fiber stream using an enzyme to release the cellulosic fibers from the polymeric materials.
- a thirteenth particular aspect includes the twelfth particular aspect, wherein the enzyme is cellulase.
- a fourteenth particular aspect includes the twelfth and/or thirteenth particular aspects, wherein the disposable absorbent article is a diaper.
- a fifteenth particular aspect includes one or more of aspects 12-14, wherein the disposable absorbent article is a post-use absorbent article.
- a sixteenth particular aspect includes one or more of aspects 12-15, further comprising transferring cellulosic fiber separated from the mixed polymeric
- a method for improving the recovery from recycling a disposable absorbent article including superabsorbent polymer includes shredding the disposable absorbent article; re-pulping the shredded disposable absorbent article; and dehydrating the superabsorbent polymer.
- the method also includes separating the pulped and shredded disposable absorbent article into a mixed polymeric material/cellulosic fiber stream and a superabsorbent polymer/fibers stream; processing the mixed polymeric material/cellulosic fiber stream using an enzyme to release the cellulosic fibers from the polymeric materials, wherein the enzyme is cellulase; and transferring cellulosic fiber separated from the mixed polymeric material/cellulosic fiber stream to the superabsorbent polymer/fibers stream.
- An eighteenth particular aspect includes the seventeenth particular aspect, wherein the disposable absorbent article is a diaper.
- a nineteenth particular aspect includes the seventeenth and/or eighteenth particular aspects, wherein the disposable absorbent article is a post-use absorbent article.
- a twentieth particular aspect includes one or more of aspects 17-19, wherein dehydrating includes belching fluid from swollen superabsorbent polymers (SAPs) by immersing swollen SAP in a gel state into a composition for removing moisture, wherein seawater and 0.5 to 3% by weight of calcium chloride based on the weight of seawater are mixed for 10 minutes to 4 hours.
- SAPs superabsorbent polymers
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Medicinal Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Sustainable Development (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
- Processing Of Solid Wastes (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Absorbent Articles And Supports Therefor (AREA)
- Paper (AREA)
Abstract
Description
Claims
Priority Applications (9)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2015408175A AU2015408175B2 (en) | 2015-08-31 | 2015-08-31 | Improving the purity of materials recycled from disposable absorbent articles |
MX2018001716A MX2018001716A (en) | 2015-08-31 | 2015-08-31 | Improving the purity of materials recycled from disposable absorbent articles. |
PCT/US2015/047736 WO2017039615A1 (en) | 2015-08-31 | 2015-08-31 | Improving the purity of materials recycled from disposable absorbent articles |
RU2018107567A RU2694344C1 (en) | 2015-08-31 | 2015-08-31 | Improved purity of materials obtained during processing of disposable absorbent articles |
EP15903202.8A EP3344426B1 (en) | 2015-08-31 | 2015-08-31 | Improving the purity of materials recycled from disposable absorbent articles |
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US15/751,338 US10493661B2 (en) | 2015-08-31 | 2015-08-31 | Improving the purity of materials recycled from disposable absorbent articles |
KR1020187006599A KR102335500B1 (en) | 2015-08-31 | 2015-08-31 | Improving the purity of recycled materials from disposable absorbent articles |
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WO2022093672A1 (en) * | 2020-10-28 | 2022-05-05 | The Procter & Gamble Company | Cementitious compositions comprising recycled superabsorbent polymer |
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US11433158B2 (en) * | 2017-12-12 | 2022-09-06 | The Procter & Gamble Company | Recycle friendly and sustainable absorbent articles |
KR102503850B1 (en) * | 2018-12-14 | 2023-02-23 | 주식회사 엘지화학 | Method for seperating and treating superabsorbent polymer from absorbent sanitary products |
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AU2015408175B2 (en) | 2021-08-05 |
CN107921666A (en) | 2018-04-17 |
BR112018002362B1 (en) | 2022-04-26 |
EP3344426B1 (en) | 2020-04-29 |
US20180236692A1 (en) | 2018-08-23 |
US10493661B2 (en) | 2019-12-03 |
BR112018002362A2 (en) | 2018-09-25 |
MX2018001716A (en) | 2018-05-15 |
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EP3344426A1 (en) | 2018-07-11 |
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