EP4638558A1 - Superabsorbant biodégradable - Google Patents

Superabsorbant biodégradable

Info

Publication number
EP4638558A1
EP4638558A1 EP23821697.2A EP23821697A EP4638558A1 EP 4638558 A1 EP4638558 A1 EP 4638558A1 EP 23821697 A EP23821697 A EP 23821697A EP 4638558 A1 EP4638558 A1 EP 4638558A1
Authority
EP
European Patent Office
Prior art keywords
salt
polyglutamic acid
water
absorbing
diglycidyl ether
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23821697.2A
Other languages
German (de)
English (en)
Inventor
Markus Henn
Christoph Loick
Rainer Teni
Marc Hager
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stockhausen Superabsorber GmbH
Original Assignee
Stockhausen Superabsorber GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stockhausen Superabsorber GmbH filed Critical Stockhausen Superabsorber GmbH
Publication of EP4638558A1 publication Critical patent/EP4638558A1/fr
Pending legal-status Critical Current

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Classifications

    • 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
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
    • C08J3/246—Intercrosslinking of at least two polymers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/53—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/42—Use of materials characterised by their function or physical properties
    • A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/08—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino-carboxylic acids
    • C08G69/10—Alpha-amino-carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/48—Polymers modified by chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C08K5/0025—Crosslinking or vulcanising agents; including accelerators
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/15—Heterocyclic compounds having oxygen in the ring
    • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
    • C08K5/1515—Three-membered rings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • C08L77/04—Polyamides derived from alpha-amino carboxylic acids
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/53—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium
    • A61F2013/530481—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having superabsorbent materials, i.e. highly absorbent polymer gel 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
    • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
    • C08J2377/04—Polyamides derived from alpha-amino carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2201/00—Properties
    • C08L2201/06—Biodegradable
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2201/00—Properties
    • C08L2201/08—Stabilised against heat, light or radiation or oxydation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/02—Applications for biomedical use

Definitions

  • the present invention relates to a biologically degradable superabsorber based on polyglutamic acid (salt) and the preparation thereof.
  • Superabsorbent or “superabsorber” is a common commercial term referring to polymeric particles capable of absorbing huge amounts of water without releasing it under pressure. Other common terms are “super-absorbent material” (SAM), “super-absorbent polymers” (SAP) or “absorbent gelling material” (AGM).
  • SAM super-absorbent material
  • SAP super-absorbent polymers
  • AGM absorbent gelling material
  • the superabsorbent When absorbing water, the superabsorbent swells impetuously; the water is caged within its polymeric network so that the water-laden superabsorbent forms a hydrogel. Likewise water, superabsorbents absorb saline and different kinds of body fluids. Due to this capacity, superabsorbents serve as a key ingredient for personal hygiene products like baby diapers, feminine care products and incontinence articles.
  • EP 0 538 904 A1 and U.S. Pat. No. 5,247,072 describe superabsorbers based upon carboxyalkyl polysaccharides.
  • the process involves a thermal crosslinking step which is very sensitive to small changes of the pH value, the temperature of the reaction duration, absorbers with widely varying absorption properties are obtained with a tendency of shortened storage time duration.
  • polyglutamic acid Due to its bio-based and biodegradable properties, polyglutamic acid (PGA) and its use as superabsorbent material was also investigated.
  • the International Application WO 2021/242936 A1 reports the manufacture of a superabsorbent based upon polyglutamic acid which may be additionally modified.
  • the superabsorbent shows mediocre performance with respect to common parameters used to assess a superabsorber, such as centrifugal retention capacity (CRC), absorption against pressure (AAP), saline flow conductivity (SFC) and absorption speed (Vortex and FSR), especially after the surface-crosslinking step.
  • CRC centrifugal retention capacity
  • AAP absorption against pressure
  • SFC saline flow conductivity
  • Vortex and FSR absorption speed
  • CRC centrifugal retention capacity
  • AAP absorption against pressure
  • SFC saline flow conductivity
  • Vortex and FSR absorption speed
  • a method for producing a water-absorbing polyglutamic acid (salt) comprising the method steps of: i) providing an aqueous mixture of a non-crosslinked polyglutamic acid (salt) and at least one crosslinker, ii) crosslinking the non-crosslinked polyglutamic acid (salt) to obtain a crosslinked polyglutamic acid (salt)-gel, iii) drying the crosslinked polyglutamic acid (salt)-gel to obtain a dried crosslinked waterabsorbing polyglutamic acid (salt), iv) heat treating the dried crosslinked water-absorbing polyglutamic acid (salt) in the presence of at least one facilitator to obtain the water-absorbing polyglutamic acid (salt).
  • a contribution to achieving the object is made by a method for producing a water-absorbing polyglutamic acid (salt), comprising the method steps of i) providing an aqueous mixture of a noncrosslinked polyglutamic acid (salt) and at least one crosslinker, ii) crosslinking the non-crosslinked polyglutamic acid (salt) to obtain a crosslinked polyglutamic acid (salt)-gel, iii) drying the crosslinked polyglutamic acid (salt)-gel to obtain a dried crosslinked water-absorbing polyglutamic acid (salt), and iv) heat treating the dried crosslinked water-absorbing polyglutamic acid (salt) in presence of at least one facilitator to obtain the water-absorbing polyglutamic acid (salt) provides for a sustainable and biologically degradable water-absorbing polyglutamic acid (salt).
  • the employed non-crosslinked polyglutamic acid (salt) of the present invention can be partially neutralized. Preferably, at least 50 mol-%, more preferably at least 70 mol-% and even more preferably at least 80 mol-% of the non-crosslinked polyglutamic acid is neutralized and present as salt.
  • the neutralization can be accomplished by using standard techniques and methods known by the skilled person. For example, an aqueous solution of sodium hydroxide can be used. Suitable cations are lithium, sodium, and potassium and preferably sodium, potassium, and a mixture thereof are selected.
  • the non-crosslinked polyglutamic acid is selected from a-polyglutamic acid and y-polyglutamic acid, preferably y-polyglutamic acid is selected.
  • the non-crosslinked polyglutamic acid (salt) has a molecular weight of 200,000 Dalton to 3,000,000 Dalton, preferably 500,000 Dalton to 2,000,000 Dalton, more preferably 700,000 Dalton to 1 ,100,000 Dalton .
  • Aqueous mixture refers to a mixture comprising at least 40 wt.%, preferably at least 50 wt.%, more preferably at least 60 wt.%, and even more preferably 70 wt.% water based on total weight of the aqueous mixture.
  • the at least one crosslinker used in step i) is selected from the group consisting of glycidyl ether such as diglycidyl ether, triglycidyl ether, polyglycidyl ether containing 3 or more epoxy groups, diglycerol tetraglycidyl ether, dipentaerythritol tetraglycidyl ether, pentaerythritol polyglycidyl ether, sorbitol polyglycidyl ether, isosorbide glycidyl ethers, polyglycerol-3-glydidyl ether, or other aliphatic polyfunctional epoxides, 1 ,4-butanediol diglycidyl ether, 1 ,6-hexanediol diglycidyl ether, propylene glycol diglycidyl ether, di propylene glycol diglycidyl ether, trimethylolpropane trig
  • ERISYS® GE-61 from CVC Thermoset Specialties, any type of cyclic and aromatic poly glycidyl ethers, or a combination of more than one crosslinker of the class of glycidyl ether.
  • the employed at least one crosslinker can be based on the carbodiimide chemistry and can be selected from 1-ethyl-3-(3-dimethylamino propyl)carbodiimide hydrochloride, dicyclohexyl carbodiimide or other carbodiimides containing compounds or a combination of carbodiimide functionality containing crosslinker with other crosslinkers e.g.
  • crosslinker of the group of glycidyl ethers saccharides such as glucose, maltotriose or cyclodextrin in the presence of water-soluble carbodiimide containing compound can be used such as water-soluble chitosan, polyethylene glycol or other organic poly alcohols, aryl azide or diazirine or other photoreactive chemical hetero bi-functional crosslinking agents acting as receptor-ligand-interaction complexes by a 2-step activation, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether and 1 ,4-butanediol diglycidyl ether.
  • a crosslinker selected from the group consisting of ethylene glycol diglycidyl ether, Poly(ethylenglycol)diglycidylether and 1 ,4-butanediol diglycidyl ether is used.
  • the average molecular weight of such crosslinker may be below 2000 g/mol, for instance 500 g/mol.
  • the aqueous mixture contains a water-soluble polymer which can be selected from the group consisting of a water-soluble polymer derived from the ethylenically unsaturated monomers containing acid groups defined in the International Application WO 2004/037903 A2, which is introduced herewith by reference and thus forms part of the disclosure.
  • the polymers can be based on the acrylic acid and methacrylic acid, acrylamides, and methacrylamides.
  • Preferred (meth)acrylamides are, in addition to acrylamide and methacrylamide, alkyl-substituted (meth)acrylamides or amino alkyl-substituted derivatives of (meth)acrylamide, such as N-methylol(meth)acrylamide, N,N-dimethylamino(meth)acrylamide, dimethyl- (meth)acrylamide or diethyl(meth)acrylamide.
  • Possible vinylamides are, for example, N- vinylamides, N-vinylformamides, N-vinylacetamides, N-vinyl-N-methylacetamides, N-vinyl-N-methyl formamides and vinylpyrrolidone.
  • the water-soluble polymer can be based on alkoxypolyalkylene oxide(meth)acrylates, such as methoxy polyethylene glycol(meth)acrylates, acrylic acid esters and methacrylic acid esters, such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate or butyl(meth)acrylate.
  • alkoxypolyalkylene oxide(meth)acrylates such as methoxy polyethylene glycol(meth)acrylates, acrylic acid esters and methacrylic acid esters, such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate or butyl(meth)acrylate.
  • These monomers can also include methyl polyethylene glycol allyl ether, vinyl acetate, styrene and isobutylene.
  • the aqueous mixture provided in step i) comprises: a) 10.0 wt.% to 50.0 wt.%, preferably 20.0 wt.% to 40.0 wt.%, and more preferably 30.0 wt.% polyglutamic acid (salt) based on the total weight of the aqueous mixture, b) 0.1 wt.% to 4.0 wt.%, preferably 0.3 wt.% to 3.0 wt.%, and more preferably 0.5 wt.% to 2.0 wt.% of the at least one crosslinker based on the total weight of the polyglutamic acid (salt), c) 0.0 wt.% to 10.0 wt.%, preferably 0.0 wt.% to 5.0 wt.%, and more preferably 0.1 to 2.5 wt.% of a water-soluble polymer, and d) 30.0 wt.% to 90.0 wt.%, preferably 50.0 wt
  • step ii) of the method according to the present invention is preferably conducted within 10 min to 50 min, preferably within 20 min to 40 min, and more preferably within 30 min.
  • step ii) is conducted under atmospheric pressure.
  • step ii) is conducted under agitation. More preferably, step ii) is conducted under agitation and under atmospheric pressure.
  • the crosslinking is conducted in a kneader reactor.
  • the kneader reactor can be a single shaft kneader reactor. In another embodiment, the kneader reactor has at least two kneading shafts.
  • Kneader type reactors are equipped with agitating means for disintegrating the polymerizing material right in the reaction vessel.
  • Using a kneader reactor provides advantages over other common apparatuses such as a belt, as it ensured effective mixing and provides a homogeneous mixture.
  • step ii) of the inventive method comprises a first stage and a second stage.
  • the first stage is conducted under maximum agitation and the second stage at 20 % to 60 %, preferably 30 % to 50 % and more preferably 40 % of the maximum agitation.
  • the time duration of the first stage is between 50 % to 82 %, preferably 58 % to 76 %, and more preferably 66 % of the total time duration of step ii).
  • This method step is preferably conducted at a temperature of at least 80 °C, more preferably at least 90 °C, and even more preferably of at least 100 °C.
  • the afore-mentioned temperature refers to the temperature of the chemical compounds present in step ii) comprising crosslinked polyglutamic acid (salt)-gel and non-crosslinked polyglutamic acid (salt).
  • the reaction vessel is ideally pre-heated to a specific temperature before the aqueous mixture is filled into the reaction vessel. A temperature of 120 °C is preferred.
  • a concentration of 33.0 wt.% polyglutamic acid referred to the total weight of the aqueous solution applying a reaction vessel temperature of -120 °C in step ii) as well as using the first and second stage as described above and a fill grade of at least 50 vol.% is advantageous for the thus obtained crosslinked polyglutamic acid (salt)-gel and also the final product performance.
  • a reactor without agitating means may be used, for example a belt reactor.
  • crosslinked polyglutamic acid (salt)-gel shall be disintegrated before drying. This enhances the drying efficiency.
  • gel obtained from a kneader reactor may be disintegrated before drying as well. The disintegrating of the gel can, for example, be performed by means of an extruder or a chopper or a mincer or other common apparatuses.
  • the drying step iii) of the method according to the invention can be accomplished by common apparatuses and techniques.
  • the gel can be dried by using a bed drier, a plate belt drier, or a fluidized bed drier or by using a microwave or convection drier.
  • the drying in step iii) is preferably conducted for 5 min to 15 min, more preferably for 10 min at a temperature of between 100 °C to 160 °C, preferably between 115 °C to 145 °C, and more preferably at a temperature of 130 °C. Shorter drying time and/or lower drying temperature leads to wet material, whereas longer drying time and/or higher drying temperature results in undesired CRC loss and AAP loss of the water-absorbing polyglutamic acid (salt).
  • the crosslinked polyglutamic acid-gel is preferably turned by 180 ° after 40 % to 60 %, preferably after 50 % of the drying step is conducted. This ensures even gel drying.
  • the hot air stream used in the dryer may have a velocity of 4 m/s to 7 m/s, preferably of 5.5 m/s.
  • the dried polyglutamic acid-gel is subject to a grinding step and a sieving step prior to step iv).
  • the sieving apparatus used in the sieving step shall have at least two sieves, the first sieve has a mesh size of 850 pm and the second mesh size of 150 pm.
  • the dried crosslinked water-absorbing polyglutamic acid (salt) is heat treated in the presence of at least one facilitator to obtain the water-absorbing polyglutamic acid (salt).
  • “In presence of at least one facilitator” in this context means that the facilitator is brought into contact with the dried crosslinked water-absorbing polyglutamic acid (salt) prior to the heat treatment or over the course of heat treatment, preferably prior to the heat treatment.
  • means known in the art can be used, for example, spraying the facilitator onto the dried crosslinked waterabsorbing polyglutamic acid (salt) and, if needed, by simultaneous or subsequent mixing of the obtained mixture. Ideally, it should be ensured that the facilitator is evenly spread over the dried crosslinked water-absorbing polyglutamic acid (salt).
  • the heat treating of the dried crosslinked water-absorbing polyglutamic acid (salt) in step iv) is conducted at a temperature ranging from 130 °C to 170 °C, preferably at 150 °C for 10 minutes to 90 minutes, preferably for 20 minutes to 60 minutes.
  • the at least one facilitator according to the invention can be selected from the group consisting of surface-crosslinker, water, and additives.
  • the surface-crosslinker which can be applied in step iv) is selected from the group consisting of polyols, for example ethylene glycol, polyethylene glycols such as diethylene glycol, triethylene glycol and tetraethylene glycol, propylene glycol, polypropylene glycols such as dipropylene glycol, tripropylene glycol or tetrapropylene glycol, ethylene glycol diglycidyl ether (EGDGE) 1 ,3- butanediol, 1 ,4-butanediol, 1 ,5-pentanediol, 2,4-pentanediol, 1 ,6-hexanediol, 2,5-hexanediol, 1 ,4- butandiol diglycidyl ether (BDDGE), glycerine,
  • surface crosslinkers are in addition polyoxazolines such as 1 ,2-ethylenebisoxazoline, crosslinkers with silane groups such as y-glycidooxypropyl trimethoxysilane and y-aminopropyl trimethoxy silane, oxazolidinones such as 2-oxazolidinone, bis- and poly-2-oxazolidinone and diglycolsilicates.
  • the surfacecrosslinker is selected from ethylene glycol diglycidyl ether (EGDGE) and 1 ,4-butandiol diglycidyl ether (BDDGE).
  • 0.10 wt.% to 2.00 wt.% of the surface-crosslinker is regularly used, preferably 0.25 wt.% to 1 .40 wt.%, and more preferably 0.50 wt.% to 0.80 wt.% based on the total amount of the dried crosslinked water-absorbing polyglutamic acid (salt).
  • water can also be used in step iv).
  • 1 .0 wt.% to 5.0 wt.%, preferably 2.0 wt.% to 4.0 wt.%, and more preferably 3.0 wt.% water is used based on the total amount of the dried crosslinked water-absorbing polyglutamic acid (salt).
  • salt polyglutamic acid
  • the water assists the heat treating which is beneficial to the performance of the final product, especially to the centrifuge retention capacity and absorption against pressure.
  • water is used as facilitator in the absence of any other chemical compounds such as organic compounds including, but not limited to, organic solvents, organic surface crosslinkers, organic additives, or organic metal salts, and also in the absence of inorganic compounds such as, but not limited to, metal salts, water-soluble and waterinsoluble inorganic compounds. “In the absence” means that the water employed comprises less than 1 .0 wt.%, preferably less than 0.5 wt.%, more preferably less than 0.1 wt.% of any other chemical compound with respect to the total amount of the water employed.
  • an additive can be used for the purpose of improving properties such as gel strength, permeability, processability, odor control, color, etc.
  • these additives may be applied before, during or after the surface crosslinking step. They can also be applied without surface-crosslinking.
  • the water-absorbing polyglutamic acid (salt) according to the invention may include 0.01 wt.% to 5.00 wt.%, or 0.01 wt.% to 1 .00 wt.%, or 0.01 wt.% to 0.05 wt.% of a penetration modifier based on the total weight of the dried crosslinked water-absorbing polyglutamic acid (salt).
  • penetration modifiers include compounds which alter the penetration depth of the surfacemodifying agents into the water-absorbing polyglutamic acid (salt), fiber, film, foam or bead by changing the viscosity, surface tension, ionic character or adhesion of said agents or medium in which these agents are applied.
  • Penetration modifiers may include polyethylene glycols, tetraethylene glycol dimethyl ether, monovalent metal salts, surfactants and water-soluble polymers.
  • the water-absorbing polyglutamic acid (salt) according to the invention may include 0.01 wt.% to 5.00 wt.%, or 0.01 wt.% to 1 .00 wt.%, or 0.01 wt.% to 0.05 wt.% of a multivalent metal salt based on the total weight of the dried crosslinked water-absorbing polyglutamic acid (salt).
  • the multivalent metal salt is preferably water soluble.
  • metal cations include, but are not limited to, the cations of Al, Fe, Zr, Mg, Ce, and Zn.
  • the multivalent metal salt has a valence of +3, with AI(+3) being most preferred.
  • Examples of anions in the multivalent metal salt include halides, sulfates, nitrates, lactates, and acetates, with chlorides, sulfates, acetates, and lactates being preferred, sulfates and lactates being more preferred.
  • Aluminum sulfate and aluminum lactate are examples of multivalent metal salt and are readily commercially available and show great performance.
  • the preferred form of aluminum sulfate is hydrated aluminum sulfate, preferably aluminum sulfate with 12 to 14 water molecules.
  • Mixtures of multivalent metal salts may be employed.
  • the dried crosslinked water-absorbing polyglutamic acid (salt) and multivalent metal salt suitably are mixed by dry blending, or in solution, using means well known to those skilled in the art.
  • a binder may be employed in an amount which is sufficient to ensure that a substantially uniform mixture of the salt and the superabsorbent polymer is maintained.
  • the binder may be water or a low volatile organic compound having a boiling point of at least 150 °C.
  • binders include water, polyols such as propylene glycol, glycerin and polyethylene glycol).
  • the water-absorbing polyglutamic acid (salt) according to the invention can comprise 0.01 wt.% to 5.00 wt.%, or 0.01 wt.% to 1 .00 wt.%, or 0.01 wt.% to 0.05 wt.% of a water-insoluble, inorganic powder based on the total weight of dried crosslinked the water-absorbing polyglutamic acid (salt).
  • insoluble, inorganic powders include silicon dioxide, silicic acid, silicates, titanium dioxide, aluminum oxide, magnesium oxide, zinc oxide, talc, calcium phosphate, clays, diatomaceous earth, zeolites, bentonite, kaolin, hydrotalcite, activated clays and apatites.
  • the insoluble inorganic powder additive may be a single compound, or a mixture of compounds selected from the above list.
  • silica is SIPERNAT® 22S fumed silica commercially available from Evonik Industries.
  • Prefered particle diameters of the inorganic particles are in the range from 10*10 -9 m to 10*10 -6 m.
  • the water-absorbing polyglutamic acid (salt) of the present invention comprises 0.01 wt.% to 5.00 wt.%, or 0.01 wt.% to 1 .00 wt.%, or 0.01 wt.% to 0.05 wt.% of a polymeric coating, such as a thermoplastic coating, or a cationic coating, or a combination of a thermoplastic coating and a cationic coating based on the total weight of the dried crosslinked water-absorbing polyglutamic acid (salt).
  • the polymeric coating is a polymer that may be in a solid, emulsion, suspension, colloidal, or solubilized form, or combinations thereof.
  • Polymeric coatings suitable for this invention may include, but are not limited to, a thermoplastic coating having a thermoplastic melt temperature wherein the polymeric coating is applied to the particle surface coincident with or followed by a temperature of the treated superabsorbent polymer particle at the thermoplastic melt temperature.
  • thermoplastic polymers include polyolefin, polyethylene, polyester, polyamide, polyurethane, styrene polybutadiene, linear low density polyethylene (LLDPE), ethylene acrylic acid copolymer (EAA), ethylene alkyl methacrylate copolymer (EMA), polypropylene (PP), maleated polypropylene, ethylene vinyl acetate copolymer (EVA), polyester, polyamide, and blends of all families of polyolefins, such as blends of PP, EVA, EMA, EEA, EBA, HDPE, MDPE, LDPE, LLDPE, and/or VLDPE, may also be advantageously employed.
  • maleated polypropylene is a preferred thermoplastic polymer for use in the present invention.
  • a thermoplastic polymer may be functionalized to have additional benefits such as water solubility or dispersibility.
  • a cationic polymer as used herein refers to a polymer or mixture of polymers comprising a functional group or groups having a potential of becoming positively charged ions upon ionization in an aqueous solution. Suitable functional groups for a cationic polymer include, but are not limited to, primary, secondary, or tertiary amino groups, imino groups, imido groups, amido groups, and quaternary ammonium groups.
  • Examples of synthetic cationic polymers include the salts or partial salts of poly(vinyl amines), poly(allylamines), polyethylene imine), poly(amino propanol vinyl ethers), poly(acrylamidopropyl trimethyl ammonium chloride), poly(diallyldimethyl ammonium chloride).
  • Examples of natural-based cationic polymers include partially deacetylated chitin, chitosan, and chitosan salts.
  • Synthetic polypeptides such as polyasparagins, polylysines, and polyarginines are also suitable cationic polymers.
  • additives that enhance whiteness of the polymer or the long-term color stability such as against darkening, yellowing or browning may also be employed.
  • Such additives are well known in the art and include anti-oxidants, sulfur- and phosphorous-containing compounds, chelating agents, optical brighteners and the like.
  • Preferred additives for color stability are 2-hydroxy- 2- sulfonato acetic acid, bisulfites, phosphonates, ethylene diamine tetraaceticacid, ethylene diamine- N,N’-disuccinic acid, diethylene diamine pentaacetic acid, their salts and derivatives, and mixtures thereof.
  • additional surface additives may optionally be employed with the particulate superabsorbent polymer compositions, including odor-binding or odor controlling substances, such as cyclodextrins, zeolites, inorganic or organic salts, similar materials and the tannins described in the European Patent EP 2 176 325 B1 which are included herein by reference and thus forms part of the disclosure; anti-caking additives, flow modification agents, surfactants, viscosity modifiers, and the like.
  • surface additives may be employed that perform several roles during surface modifications.
  • a single additive may be a surfactant, viscosity modifier, and may react to crosslink polymer chains.
  • the additional surface additives may comprise a chelating agent.
  • the chelating agent preferably may be selected from organic polyacids, phosphoric polyacids and salts thereof.
  • the chelating agent may be selected from nitrilotriacetic acid, ethylene diamine tetraacetic acid, cyclohexane diamine tetraacetic acid, diethylene triamine pentaacetic acid, diethylenetriamine penta(methylene phosphonic acid), ethyleneglycol-bis-(aminoethylether)-N,N,N’-triacetic acid, N-(2-hydroxyethyl)-ethylene diamine- N,N,N’-triacetic acid, triethylene tetraamine hexaacetic acid, tartaric acid, citric acid, imino disuccinic acid, gluconic acid, phosphonates and salts thereof.
  • step i) The steps of the method according to the invention are conducted in the sequence step i), step ii), step iii), and then step iv).
  • the present invention also relates to a water-absorbing polyglutamic acid (salt) obtainable by a method described herein.
  • the water-absorbing polyglutamic acid (salt) possess a particulate form and/or the water-absorbing polyglutamic acid (salt) possess a particle size distribution of between 150 pm to 850 pm.
  • at least 80 wt.%, more preferably at least 90 wt.% of the water-absorbing polyglutamic acid (salt) has a particle size distribution of between 150 pm to 850 pm.
  • the water-absorbing polyglutamic acid (salt) obtainable according to present process achieves at least one of the following performance parameters: • an absorption against pressure of 4.83 kPa (0.7 psi) of more than 9 g/g and less than 30 g/g or less than 26 g/g, preferably less than 25 g/g, as measured as defined in the description;
  • centrifugal retention capacity of more than 20 and less than 46 g/g, preferably more than 25 and less than 42 g/g as measured as defined in the description;
  • the water-absorbing polyglutamic acid (salt) exhibits the AAP and CRC values mentioned above.
  • Cited values are resulting from inventive preparation method.
  • Yet another object of the present invention is an article comprising the water-absorbing polyglutamic acid (salt) with at least one of the performance parameters or which is obtainable by the method according to the present invention.
  • Said article is preferably a personal hygiene article such as a diaper, a sanitary towel, or a napkin. Besides that, the article may be a wound covering.
  • inventive waterabsorbing polyglutamic acid (salt) include medicine/pharmaceutical applications where it can be used as or in biological glue, dental carriers, bone regeneration, cartilage regeneration, vaccine development scaffolds in tissue engineering, drug delivery system, and biological control agent. Further applications are agricultural, e.g.
  • biofertilizer for improving the soil water availability, the use as biofertilizer, in wastewater treatment, as bio flocculant, in the food industry as thickener, oil reducing agent, flavoring agent, cryoprotectant, and in cosmetics, such as sunscreens, hair growth serums, anti-aging serums, mouth wash, and contact lens care solutions.
  • Superabsorbents are usually purchased by manufacturers of personal hygiene products. For purchase decision, the overall performance profile of a superabsorbent is crucial. The required performance profile strongly depends on the type and purpose of the hygiene article. During the last decades, a bunch of performance parameters has been established by the market participants for comparing the suitability of different SAP qualities for an intended purpose. Some of those performance parameters are standardized by independent authorities, others are defined by certain manufacturers of hygiene products for their individual needs only. Actually, both types of performance parameters are of importance within the real-life SAP market. Besides that, the patent literature is jam-packed with parameters which do not have any impact outside a certain patent right at all.
  • the centrifuge retention capacity refers to the fluid retention capacity without pressure.
  • AAP Absorption against pressure
  • the absorption against pressure refers to the capacity of absorbing urine when subjected to an external pressure.
  • the AAP was measured at a pressure of 4.83 kPa (which is egual to 0.7 psi).
  • the saline flow conductivity refers to the ability of a gel to transfer fluids once a first contact with body fluid has occurred.
  • the test method is disclosed in the International Publication WO-A- 95/26209, pages 69 to 75, although 1 .5 g of the to-be-investigated superabsorbent was used instead of 0.9 g.
  • This parameter relates to the swelling speed of a water-absorbent polymer.
  • the time needed for the absorption, which was measured with the stopwatch, is denoted t.
  • the disappearance of the last drop of liguid on the surface is defined as time t.
  • the free swell rate (FSR) is calculated as follows:
  • the unit of the FSR is g g -1 s -1 .
  • the vortex time refers to the time in seconds until the vortex disappeared after adding 2 g of a water-absorbent polymer to 50 mL of physiological saline solution and then stirring the mixture at 600 rpm.
  • a 100 mL glass beaker (Pyrex #1060-100 or Fisher Brand #FB-102-100) was used together with a magnetic stirring rod (size 38.4 mm x 8 mm).
  • the saline temperature was set to be between 24 °C and 25 °C and the temperature of the room was above 21 °C.
  • the humidity was set to be within the limitations of EDANA Standard Test WSP 241 .2 (05).
  • the crosslinking reactions were conducted in a single shaft kneader reactor of the type Discotherm Batch, DTB1 .5, obtained from List AG, Switzerland, with a total volume of 3.1 liters.
  • the reactor is equipped with a jacket for heating and cooling, a vacuum system, a nitrogen supply system, and a reactor control unit.
  • the reactor was previously heated up to more than 110 °C (set temperature of the heating device: 120 °C).
  • the temperature was measured in the jacket of the kneader reactor.
  • the pressure of the vessel is the atmospheric pressure.
  • the reactor is kept open and at the previous mentioned temperature over the entire reaction.
  • the agitation is set to the maximum (100 % of the potentiometer, 65 rpm) for 20 minutes to allow the PGA to dissolve completely and the mixture to reach the wished temperature. After this, the agitator is set to 40 % which is 24 rpm, for additional 10 minutes. Thereafter, the endplate of the reactor is removed to discharge the free flowing and granulated gel from the reactor. The obtained polymer is further processed.
  • the granulated gel obtained from the crosslinking in the DTB 1.5 I reactor is extruded in a kitchen type meat mincer (Mado Kitchen Fleischwolf MEW 710-R70) equipped with a die plate of 8mm thickness having 45 holes each with a diameter of 6 mm.
  • a portion of 600 to 900 grams of the extruded gel is then placed in the fluidization chamber of the dryer.
  • the gel to be dried is placed on the plate, the gel bed having a thickness of about 5 cm to 8 cm and is dried in the hot air stream at 5.5 m/s air inlet velocity at 130 °C or 140 °C for 15 minutes or 20 minutes, respectively.
  • the pre-dried material is turned by 180° to allow a homogeneous drying on both sides for further 5 or 10 minutes.
  • the dry polymer obtained is ground in a Bauerffle lab roll mill and sieved in a Retsch sieve tower equipped with the sieves having mesh sizes of 850 and 150 microns, obtaining the particle size fraction for analysis of the precursor superabsorber.
  • crosslinker ethylene glycol diglycidyl ether (EGDGE) or 1 ,4-butandiol diglycidyl ether (BDDGE) were employed. Additives such as isopropanol, aluminum lactate were used. Also, water was employed as facilitator.
  • the coated precursor was divided into 3 portions and heated in a circulating air-drying oven Heraeus UT6120 for 20 to 60 minutes at 150 °C.
  • the surface crosslinked polymers thus obtained were sieved with a Retsch sieve having a mesh size of 850 microns to remove agglomerates formed by the coating.
  • the water-absorbing polyglutamic acid (salt) shows good simultaneous performance regarding AAP and CRC.
  • the overall performance is comparable to the performance of acrylic acid based superabsorbent polymers but the polyglutamic acid (salt) based polymers are environmentally friendly.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Organic Chemistry (AREA)
  • Polymers & Plastics (AREA)
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  • Veterinary Medicine (AREA)
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  • Vascular Medicine (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biomedical Technology (AREA)
  • Materials Engineering (AREA)
  • Hematology (AREA)
  • Dispersion Chemistry (AREA)
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  • Polyamides (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • Absorbent Articles And Supports Therefor (AREA)

Abstract

La présente invention concerne un superabsorbant biodégradable à base de (sel de) poly(acide glutamique) et sa préparation. L'objectif de l'invention est de fournir un superabsorbant biodégradable présentant des performances améliorées. Ce problème a été résolu par un procédé de préparation d'un (sel de) poly(acide glutamique) absorbant l'eau, consistant à : i) fournir un mélange aqueux d'un (sel de) poly(acide glutamique) non réticulé et d'au moins un agent de réticulation, ii) réticuler le (sel de) poly(acide glutamique) non réticulé pour obtenir un gel de (sel de) poly(acide glutamique) réticulé, iii) sécher le gel de (sel de) poly(acide glutamique) réticulé pour obtenir un (sel de) poly(acide glutamique) réticulé séché absorbant l'eau, iv) traiter thermiquement (sel de) poly(acide glutamique) réticulé séché absorbant l'eau en présence d'au moins un facilitateur pour obtenir le (sel de) poly(acide glutamique) absorbant l'eau.
EP23821697.2A 2022-12-20 2023-12-15 Superabsorbant biodégradable Pending EP4638558A1 (fr)

Applications Claiming Priority (2)

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EP22214780.3A EP4389797A1 (fr) 2022-12-20 2022-12-20 Superabsorbant biodégradable
PCT/EP2023/086141 WO2024132959A1 (fr) 2022-12-20 2023-12-15 Superabsorbant biodégradable

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EP4638558A1 true EP4638558A1 (fr) 2025-10-29

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EP23821697.2A Pending EP4638558A1 (fr) 2022-12-20 2023-12-15 Superabsorbant biodégradable

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EP (2) EP4389797A1 (fr)
JP (1) JP2025541787A (fr)
KR (1) KR20250127110A (fr)
CN (1) CN120476169A (fr)
TW (1) TW202432663A (fr)
WO (1) WO2024132959A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5247072A (en) 1991-10-25 1993-09-21 Kimberly-Clark Corporation Carboxyalkyl polysaccharides having improved absorbent properties and process for the preparation thereof
CA2073292C (fr) 1991-10-25 2004-06-29 Xin Ning Carboxyalkylpolysaccharides a proprietes absorbantes ameliorees et procede d'obtention
US5599335A (en) 1994-03-29 1997-02-04 The Procter & Gamble Company Absorbent members for body fluids having good wet integrity and relatively high concentrations of hydrogel-forming absorbent polymer
TWI378955B (en) 2002-10-25 2012-12-11 Evonik Stockhausen Gmbh Absorbent polymer structure with improved retention capacity and permeabilty
DE102007045724B4 (de) 2007-09-24 2012-01-26 Evonik Stockhausen Gmbh Superabsorbierende Zusammensetzung mit Tanninen zur Geruchskontrolle, Verfahren zu deren Herstellung und Verwendung
JP6474251B2 (ja) * 2014-12-25 2019-02-27 株式会社リブドゥコーポレーション 吸水性樹脂およびその製造方法
KR20230035254A (ko) 2020-05-26 2023-03-13 자이모켐 인코포레이티드 생분해성 고성능 흡수성 중합체 및 이의 방법

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EP4389797A1 (fr) 2024-06-26
WO2024132959A1 (fr) 2024-06-27
CN120476169A (zh) 2025-08-12
KR20250127110A (ko) 2025-08-26
TW202432663A (zh) 2024-08-16

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