EP4263630A1 - Procédé de production de particules superabsorbantes - Google Patents

Procédé de production de particules superabsorbantes

Info

Publication number
EP4263630A1
EP4263630A1 EP21823321.1A EP21823321A EP4263630A1 EP 4263630 A1 EP4263630 A1 EP 4263630A1 EP 21823321 A EP21823321 A EP 21823321A EP 4263630 A1 EP4263630 A1 EP 4263630A1
Authority
EP
European Patent Office
Prior art keywords
polymer gel
undersize
weight
polymer
separated
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
EP21823321.1A
Other languages
German (de)
English (en)
Inventor
Ruediger Funk
Matthias Weismantel
Marcus MAEMECKE
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.)
BASF SE
Original Assignee
BASF SE
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 BASF SE filed Critical BASF SE
Publication of EP4263630A1 publication Critical patent/EP4263630A1/fr
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F6/00—Post-polymerisation treatments
    • C08F6/008—Treatment of solid polymer wetted by water or organic solvents, e.g. coagulum, filter cakes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • B01J20/265—Synthetic macromolecular compounds modified or post-treated polymers
    • B01J20/267—Cross-linked polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3085—Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
    • 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
    • C08J3/005—Processes for mixing polymers
    • 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
    • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
    • C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
    • C08J3/075—Macromolecular gels
    • 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
    • C08J3/12—Powdering or granulating
    • 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
    • C08J3/12—Powdering or granulating
    • C08J3/16—Powdering or granulating by coagulating dispersions
    • 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
    • C08J3/245—Differential crosslinking of one polymer with one crosslinking type, e.g. surface crosslinking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/50—Aspects relating to the use of sorbent or filter aid materials
    • B01J2220/68—Superabsorbents
    • 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
    • C08J2333/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C08J2333/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2433/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C08L101/12—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
    • C08L101/14—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity the macromolecular compounds being water soluble or water swellable, e.g. aqueous gels

Definitions

  • the present invention relates to a method for producing thermally surface-postcrosslinked superabsorbent particles, comprising polymerization of a monomer solution or suspension, static drying of the aqueous polymer gel obtained, comminution of the dried polymer gel, classification of the polymer particles obtained, with polymer particles that are too small being separated off as undersize, mixing the separated off Undersize with an aqueous solution, wherein the aqueous solution contains a crosslinker, and recycling of the polymer gel obtained from the undersize into the static drying.
  • Superabsorbents are used in the manufacture of diapers, tampons, sanitary napkins and other hygiene articles, but also as water-retaining agents in agricultural horticulture.
  • the superabsorbers are also referred to as water-absorbing polymers.
  • superabsorbent particles are generally surface postcrosslinked. This increases the degree of crosslinking of the particle surface, whereby the absorption under a pressure of 49.2 g/cm 2 (AUL0.7psi) and the centrifuge retention capacity (CRC) can be at least partially decoupled.
  • This surface post-crosslinking can be carried out in an aqueous gel phase.
  • dried, ground and sieved polymer particles base polymer
  • Crosslinkers suitable for this purpose are compounds which can form covalent bonds with at least two carboxylate groups of the polymer particles.
  • EP 0 789 047 A1 describes a process for producing superabsorbents, in which polymer particles are agglomerated with an aqueous solution and the aqueous solution contains a crosslinker.
  • WO 2019/221235 A1 and WO 2019/221236 A1 describe processes for producing superabsorbent particles, polymer particles being agglomerated with water and the polymer gel obtained being recycled.
  • the object of the present invention was to provide an improved process for producing superabsorbent particles, in particular for producing superabsorbent particles with a high absorption rate.
  • the object was achieved by a process for producing superabsorbent particles by polymerizing a monomer solution or suspension containing a) at least one ethylenically unsaturated, acid-group-carrying monomer which is at least partially neutralized, b) at least one crosslinker 1 and c) at least one initiator, comprising the steps i) polymerization of the monomer solution or suspension and optional extrusion of the resulting polymer gel 1, ii) drying of the polymer gel, iii) comminution of the dried polymer gel, iv) classification of the polymer particles obtained in step iii), with too small polymer particles separated as undersize 1 and optionally oversized polymer particles are recycled in step iii), and the remaining polymer particles are thermally surface post-crosslinked in a further step, v) mixing the separated undersize with an aqueous solution and optionally extrusion of the resulting polymer gel 2 and vi) recycling of the polymer rgels 2 in step ii),
  • the present invention is based on the finding that agglomerates produced from separated undersize increase the rate of absorption. It is important here that agglomeration takes place in the presence of a crosslinking agent and that the polymer gel 2 thus obtained is dried together with the rest of the polymer gel, with the two polymer gels not being mixed.
  • the crosslinking agent is distributed uniformly over the entire polymer gel and the concentration of crosslinking agent in polymer gel 2 is reduced. This leads to more unstable agglomerates. At the same time, the polymer gel 1 is additionally crosslinked. This leads to a lower absorption capacity.
  • the separated undersize in step v) is first mixed with water and optionally extruded and then mixed with the aqueous solution and optionally extruded.
  • the separated undersize is pre-swollen before the crosslinking agent 2 is actually added.
  • the separated undersize is pre-swollen with water before the addition of the aqueous solution, preferably at least 50% by weight, particularly preferably at least 70% by weight, very particularly preferably at least 90% by weight, of the total amount of in step v) added water used for pre-soaking.
  • the total amount of water added in step v) is the amount of water added and the water content of the aqueous solution added.
  • the separated undersize in step v) is first mixed with an aqueous base and optionally extruded and then mixed with the aqueous solution and optionally extruded.
  • the separated undersize is pretreated before the crosslinking agent 2 is actually added.
  • aqueous base preferably from 0.1 to 12% by weight of base, based on the undersize.
  • bases are sodium hydroxide, sodium carbonate and sodium hydroxide roe carbonate.
  • a 50% strength by weight sodium hydroxide solution can be used as the aqueous base.
  • the pretreatment of the undersize causes crosslinks in the undersize to be hydrolyzed and the centrifuge retention capacity (CRC) of the undersize to increase.
  • CRC centrifuge retention capacity
  • the temperature in step v) is preferably from 20 to 90°C, particularly preferably from 25 to 75°C, very particularly preferably from 30 to 60°C.
  • the aqueous solution in step v) preferably contains from 0.01 to 1.0% by weight, particularly preferably from 0.02 to 0.5% by weight, very particularly preferably from 0.05 to 0.2% by weight. -%, of the crosslinker 2, in each case based on the amount of separated undersize,
  • Suitable crosslinkers 2 which can be used in step v) are compounds which can form covalent bonds with at least two carboxylate groups of the polymer particles, for example ethylene carbonate and ethylene glycol diglycidyl ether. Such compounds are also known as surface post-crosslinkers and are described there in this document.
  • crosslinkers 2 are able to form ionic bonds with at least two carboxylate groups of the polymer particles. Such compounds are also used as salts of polyvalent cations in surface post-crosslinking and are described there in this document.
  • Particularly suitable crosslinkers 2 which can be used in step v) are compounds which contain at least two epoxide groups, for example ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether and polyglycerol polyglycidyl ether.
  • ethylene glycol diglycidyl ether diethylene glycol diglycidyl ether
  • polyethylene glycol diglycidyl ether polyethylene glycol diglycidyl ether
  • propylene glycol diglycidyl ether propylene glycol diglycidyl ether
  • polypropylene glycol diglycidyl ether polypropylene glycol diglycidyl ether
  • glycerol polyglycidyl ether dig
  • the moisture content of the polymer gel obtained in step v) is preferably from 30 to 70% by weight, particularly preferably from 35 to 65% by weight, very particularly preferably from 40 to 60% by weight, the moisture content being analogous to that of the EDANA recommended test method no. WSP 230.2-05 "Mass Loss Upon Heating".
  • 90% by weight of the undersize separated in step iv) has a particle size of preferably not more than 250 ⁇ m, particularly preferably not more than 200 ⁇ m, very particularly preferably 150 ⁇ m.
  • the amount of polymer gel 2 recycled in step vi) is preferably from 1 to 50% by weight, more preferably from 10 to 40% by weight, most preferably from 20 to 30% by weight, based in each case on the total amount of polymer gels to be dried in step ii).
  • the crosslinker 2 can hydrolyze, especially when it comes to compounds that contain at least two epoxide groups. Therefore the residence time of the polymer gel 2 between steps v) and ii) should not be too long.
  • the residence time of the polymer gel 2 between steps v) and ii) is therefore preferably at most 15 minutes, particularly preferably at most 10 minutes, very particularly preferably at most 5 minutes.
  • the crosslinking reaction of crosslinker 2 should take place during drying in step ii).
  • the residence time during drying in step ii) is preferably at least 120°C, particularly preferably at least 150°C, very particularly preferably at least 170°C.
  • the residence time during drying in step ii) is preferably at least 10 minutes, particularly preferably at least 20 minutes, very particularly preferably at least 30 minutes.
  • the mass of undersize 2 in relation to the total mass of undersize is preferably at most 10% by weight, particularly preferably at most 5% by weight, very particularly preferably at most 2% by weight.
  • the process according to the invention is preferably carried out continuously.
  • the superabsorbents are produced by polymerizing a monomer solution or suspension and are usually water-insoluble.
  • the monomers a) are preferably water-soluble, ie the solubility in water at 23° C. is typically at least 1 g/100 g water, preferably at least 5 g/100 g water, particularly preferably at least 25 g/100 g water, very particularly preferably at least 35g/100g water.
  • Suitable monomers a) are ethylenically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid and itaconic acid. Particularly preferred monomers are acrylic acid and methacrylic acid. Acrylic acid is very particularly preferred.
  • the monomers a) usually contain polymerization inhibitors, preferably hydroquinone monoethers, as storage stabilizers.
  • Suitable crosslinkers b) are compounds having at least two groups suitable for crosslinking. Such groups are, for example, ethylenically unsaturated groups which can be radically polymerized into the polymer chain, and functional groups which can form covalent bonds with the acid groups of the monomer a). Furthermore, polyvalent metal salts which can form coordinate bonds with at least two acid groups of the monomer a) are also suitable as crosslinkers b).
  • Suitable crosslinkers b) are, for example, ethylene glycol dimethacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, allyl methacrylate, trimethylolpropane triacrylate, triallylamine, tetraallylammonium chloride, tetraallyloxyethane, as described in EP 0 530438 A1, di- and triacrylates, as described in EP 0 547 847 A1, EP 0 559476 A1, EP 0632 068 A1, WO 93/21237 A1, WO 03/104299 A1, WO 03/104300 A1, WO 03/104301 A1 and DE 103 31 450 A1 describe mixed acrylates which contain further ethylenically unsaturated groups in addition to acrylate groups, as described in DE 103 31 456 A1 and DE 103 55401 A1, or crosslinker mixtures as described, for example, in DE 19543 368 A1, DE 196 46484 A1, WO 90/15830 A
  • the amount of crosslinker b) is preferably from 0.05 to 1.5% by weight, particularly preferably from 0.1 to 1% by weight, very particularly preferably from 0.3 to 0.6% by weight, calculated in each case the total amount of monomer a) used.
  • the centrifuge retention capacity (CRC) decreases and the absorption under a pressure of 21.0 g/cm 2 (AUL0.3psi) passes through a maximum.
  • All compounds which generate free radicals under the polymerization conditions can be used as initiators c), for example thermal initiators, redox initiators, photoinitiators.
  • Suitable redox initiators are sodium peroxodisulfate/ascorbic acid, hydrogen peroxide/ascorbic acid, sodium peroxodisulfate/sodium bisulfite and hydrogen peroxide/sodium bisulfite.
  • Mixtures of thermal initiators and redox initiators are preferably used, such as sodium peroxodisulfate/hydrogen peroxide/ascorbic acid.
  • the disodium salt of 2-hydroxy-2-sulfonatoacetic acid or a mixture of the sodium salt of 2-hydroxy-2-sulfinatoacetic acid, the disodium salt of 2-hydroxy-2-sulfonatoacetic acid and sodium bisulfite is preferably used as the reducing component.
  • Such mixtures are available as Bruggolite® FF6 and Bruggolite® FF7 (Bruggemann Chemicals; Heilbronn; Germany).
  • aqueous monomer solution is usually used.
  • the water content of the monomer solution is preferably from 40 to 75% by weight, particularly preferably from 45 to 70% by weight, very particularly preferably from 50 to 65% by weight. It is also possible to use monomer suspensions, i.e. monomer solutions with monomer a) exceeding the solubility, for example sodium acrylate. As the water content increases, the energy required for the subsequent drying increases, and as the water content decreases, the heat of polymerization can only be dissipated insufficiently.
  • the preferred polymerization inhibitors require dissolved oxygen for optimal activity.
  • the monomer solution can therefore be freed from dissolved oxygen before the polymerization by rendering it inert, i.e. flowing through it with an inert gas, preferably nitrogen or carbon dioxide.
  • the oxygen content of the monomer solution is preferably reduced to less than 1 ppm by weight, more preferably to less than 0.5 ppm by weight, most preferably to less than 0.1 ppm by weight, before the polymerization.
  • Suitable reactors for the polymerization are, for example, kneading reactors or belt reactors.
  • the polymer gel formed during the polymerization of an aqueous monomer solution or suspension is continuously comminuted, for example by counter-rotating stirrer shafts, as described in WO 2001/038402 A1.
  • Polymerization on the belt is described, for example, in DE 3825 366 A1 and US Pat. No. 6,241,928.
  • Polymerization in a belt reactor produces a polymer gel that has to be comminuted, for example in an extruder or kneader.
  • the comminuted polymer gel obtained by means of a kneader can additionally be extruded.
  • the acid groups of the polymer gels obtained are usually partially neutralized.
  • the neutralization is preferably carried out at the monomer stage. This is usually done by mixing in the neutralizing agent as an aqueous solution or preferably also as a solid.
  • the degree of neutralization is preferably from 40 to 85 mol%, particularly preferably from 50 to 80 mol%, very particularly preferably from 60 to 75 mol%, it being possible to use the customary neutralizing agents, preferably alkali metal hydroxides, alkali metal oxides, alkali metal carbonates or alkali metal hydrogen carbonates as well their mixtures. Instead of alkali metal salts, ammonium salts can also be used.
  • Solid carbonates and hydrogen carbonates can also be used here in encapsulated form, preferably in the monomer solution directly before the polymerization, during or after the polymerization in the polymer gel and before it is dried.
  • the encapsulation is carried out by coating the surface with an insoluble or only slowly soluble material (e.g. using film-forming polymers, inert inorganic materials or fusible organic materials), which delays the solution and reaction of the solid carbonate or bicarbonate so that carbon dioxide is only released during drying is set and the resulting superabsorbent has a high internal porosity.
  • the polymer gel is then usually dried with a circulating air belt dryer until the residual moisture content is preferably 0.5 to 10% by weight, particularly preferably 1 to 7% by weight, very particularly preferably 2 to 5% by weight, with the residual moisture content according to the test method no. WSP 230.2-05 "Mass Loss Upon Heating" recommended by EDANA. If the residual moisture is too high, the dried polymer gel has a glass transition temperature T g that is too low and is difficult to process further. If the residual moisture content is too low, the dried polymer gel is too brittle and the subsequent comminution steps result in undesirably large amounts of polymer particles with too small a particle size (“fines”).
  • the solids content of the polymer gel is preferably from 25 to 90% by weight, particularly preferably from 35 to 70% by weight, very particularly preferably from 40 to 60% by weight.
  • the dried polymer gel is then broken up and optionally coarsely comminuted.
  • the dried polymer gel is then usually ground and classified, it being possible to use single-stage or multi-stage roller mills, preferably two-stage or three-stage roller mills, pinned mills, hammer mills or vibratory mills for the grinding.
  • the mean particle size of the polymer particles separated off as the product fraction is preferably from 150 to 850 ⁇ m, particularly preferably from 250 to 600 ⁇ m, very particularly from 300 to 500 ⁇ m.
  • the average particle size of the product fraction can be determined using the test method no. WSP 220.2 (05) "Particle Size Distribution” recommended by EDANA, whereby the mass fractions of the sieve fractions are applied cumulatively and the average particle size is determined graphically.
  • the mean particle size here is the value of the mesh size that results for a cumulative 50% by weight.
  • the polymer particles can be thermally surface post-crosslinked.
  • Suitable surface postcrosslinkers are compounds that contain groups that can form covalent bonds with at least two carboxylate groups of the polymer particles.
  • Suitable compounds are, for example, polyfunctional amines, polyfunctional amidoamines, polyfunctional epoxides, as described in EP 0 083 022 A2, EP 0 543 303 A1 and EP 0 937 736 A2, di- or polyfunctional alcohols, as described in DE 33 14 019 A1, DE 3523617 A1 and EP 0450 922 A2, or ⁇ -hydroxyalkylamides, as described in DE 102 04 938 A1 and US Pat. No. 6,239,230.
  • the amount of surface postcrosslinker is preferably from 0.001 to 2% by weight, particularly preferably from 0.02 to 1% by weight, very particularly preferably from 0.05 to 0.2% by weight, based in each case on the polymer particles.
  • polyvalent cations are applied to the particle surface in addition to the surface postcrosslinkers.
  • the polyvalent cations that can be used in the process according to the invention are, for example, divalent cations such as zinc, magnesium, calcium and strontium cations, trivalent cations such as aluminum, iron, chromium, rare earth and manganese cations, tetravalent cations such as titanium cations and Zirconium.
  • divalent cations such as zinc, magnesium, calcium and strontium cations
  • trivalent cations such as aluminum, iron, chromium, rare earth and manganese cations
  • tetravalent cations such as titanium cations and Zirconium.
  • chloride, bromide, hydroxide, sulfate, hydrogen sulfate, carbonate, hydrogen carbonate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate and carboxylate such as acetate and lactate are possible.
  • Aluminum hydroxide, aluminum sulfate and aluminum lactate are preferred.
  • the surface postcrosslinking is usually carried out by spraying a solution of the surface postcrosslinker onto the dried polymer particles. After spraying, the polymer particles coated with surface post-crosslinking agent are thermally treated.
  • a solution of the surface postcrosslinker is preferably sprayed on in mixers with moving mixing tools, such as screw mixers, disk mixers and paddle mixers.
  • moving mixing tools such as screw mixers, disk mixers and paddle mixers.
  • Horizontal mixers, such as paddle mixers, are particularly preferred, and vertical mixers are very particularly preferred.
  • the distinction between horizontal mixers and vertical mixers is based on the mounting of the mixing shaft, i.e. horizontal mixers have a horizontally mounted mixing shaft and vertical mixers have a vertically mounted mixing shaft.
  • Suitable mixers are, for example, Horizontal Ploughshare® Mixer (Gebr.
  • the surface post-crosslinkers are typically used as an aqueous solution.
  • the depth of penetration of the surface postcrosslinker into the polymer particles can be adjusted via the content of nonaqueous solvent or the total amount of solvent.
  • the thermal treatment is preferably carried out in contact dryers, particularly preferably paddle dryers, very particularly preferably disk dryers.
  • Suitable dryers are, for example, Hosokawa Bepex® Horizontal Paddle Dryer (Hosokawa Micron GmbH; Leingart; Germany), Hosokawa Bepex® Disc Dryer (Hosokawa Micron GmbH; Leingart; Germany), Holo-Flite® dryers (Metso Minerals Industries Inc.; Danville; USA ) and Nara Paddle Dryer (NARA Machinery Europe; Frechen; Germany).
  • fluidized bed dryers can also be used.
  • the surface post-crosslinking can take place in the mixer itself, by heating the jacket or blowing in warm air.
  • a downstream dryer such as a tray dryer, a rotary kiln or a heatable screw, is also suitable.
  • the mixture is mixed in a fluidized bed dryer and the surface post-crosslinked thermally.
  • Preferred reaction temperatures are in the range from 100 to 250°C, preferably from 110 to 220°C, particularly preferably from 120 to 210°C, very particularly preferably from 130 to 200°C.
  • the preferred residence time at this temperature is preferably at least 10 minutes, more preferably at least 20 minutes, most preferably at least 30 minutes, and usually at most 60 minutes.
  • the surface-postcrosslinked polymer particles can then be reclassified, with polymer particles that are too small and/or too large being separated off and returned to the process.
  • the surface post-crosslinked polymer particles can be coated or post-moistened to further improve their properties.
  • the subsequent moistening is preferably carried out at 30 to 80.degree. C., particularly preferably at 35 to 70.degree. C., very particularly preferably at 40 to 60.degree.
  • the amount of water used for post-wetting is preferably from 1 to 10% by weight, particularly preferably from 2 to 8% by weight, very particularly preferably from 3 to 5% by weight.
  • the remoistening increases the mechanical stability of the polymer particles and reduces their tendency to static charging.
  • the post-wetting is carried out in the cooler after the thermal surface post-crosslinking.
  • suitable coatings for improving the swelling rate and the gel bed permeability are inorganic inert substances such as water-insoluble metal salts, organic polymers, cationic polymers and divalent or polyvalent metal cations.
  • suitable coatings for dust binding are, for example, polyols.
  • Suitable coatings to counteract the undesirable tendency of the polymer particles to cake are, for example, pyrogenic silica such as Aerosil® 200, precipitated silica such as Sipernat® D17, and surfactants such as Span® 20.
  • WSP Standard Test Methods described below, labeled "WSP" are described in: “Standard Test Methods for the Nonwovens Industry", Edition 2005, published jointly by “Worldwide Strategie Partners” EDANA (Herrmann-Debrouxlaan 46, 1160 Oudergem, Belgium, www.edana.org) and INDA (1100 Crescent Green, Suite 115, Cary, North Carolina 27518, USA, www.inda.org). This release is available from both EDANA and INDA.
  • the measurements should be carried out at an ambient temperature of 23 ⁇ 2 °C and a relative humidity of 50 ⁇ 10 %.
  • the super absorber particles are thoroughly mixed before the measurement.
  • the centrifuge retention capacity (CRC) is determined according to the EDANA recommended test method No. WSP 241.2 (05) "Fluid Retention Capacity in Saline, After Centrifugation".
  • the absorption under a pressure of 49.2 g/cm 2 (AU HL) is determined analogously to the test method no. WSP 242.2 (05) "Absorption Under Pressure, Gravimetric Determination" recommended by EDANA, whereby instead of a pressure of 21.0 g/cm 2 (0.3psi) a pressure of 49.2 g/cm 2 (0.7psi) is set.
  • An acrylic acid/sodium acrylate solution was prepared by continuously mixing deionized water, 50% strength by weight sodium hydroxide solution and acrylic acid, so that the degree of neutralization corresponded to 72.0 mol %.
  • the solids content of the monomer solution was 42.5% by weight.
  • the crosslinker 1 used was 3-tuply ethoxylated glycerol triacrylate (about 85% strength by weight). The amount used was 1.2 kg per t of monomer solution.
  • the throughput of the monomer solution was 20 t/h.
  • the reaction solution had a temperature of 23.5° C. at the inlet.
  • Type List Contikneter with a volume of 6.3m 3 (LIST AG, Arisdorf, Switzerland) metered:
  • the monomer solution was rendered inert with nitrogen between the point at which the crosslinker was added and the points at which the initiators were added.
  • polymer particles with a particle size of less than 150 ⁇ m (1000 kg/h) obtained from the manufacturing process by comminution and classification were additionally metered into the reactor.
  • the residence time of the reaction mixture in the reactor was 15 minutes.
  • the polymer gel obtained (polymer gel A) was placed on the conveyor belt of a circulating air belt dryer by means of an oscillating conveyor belt.
  • the circulating air belt dryer was 48 m long.
  • the conveyor belt of the circulating air belt dryer had an effective width of 4.4 m.
  • air/gas mixture (approx. 175° C.) flowed continuously around the aqueous polymer gel and dried.
  • the residence time in the circulating air belt dryer was 37 minutes.
  • the dried polymer gel was comminuted using a three-stage roller mill and sieved off to a particle size of 150 to 850 ⁇ m. Polymer particles with a particle size of less than 150 ⁇ m were separated (polymer particles B). Polymer particles with a particle size greater than 850 ⁇ m were returned to the comminution. Polymer particles with a particle size in the range from 150 to 850 ⁇ m (polymer particles A) were thermally surface post-crosslinked.
  • the polymer particles were coated with a surface postcrosslinker solution in a Schugi Flexomix® (Hosokawa Micron B.V., Doetinchem, Netherlands) and then dried in a NARA Paddle Dryer (GMF Gouda, Waddinxveen, Netherlands) at 176° C. for 45 minutes.
  • Schugi Flexomix® Hosokawa Micron B.V., Doetinchem, Netherlands
  • NARA Paddle Dryer GMF Gouda, Waddinxveen, Netherlands
  • the surface postcrosslinker solution contained 2.2% by weight of 2-hydroxyethyl-2-oxazolidone, 2.2% by weight of 1,3-propanediol, 29.0% by weight of 1,2-propanediol, 3.2% by weight aluminum sulfate, 56.9% by weight water and 6.5% by weight isopropanol.
  • the surface post-crosslinked polymer particles were cooled to about 60° C. in a NARA paddle cooler (GMF Gouda, Waddinxveen, Netherlands).
  • the surface post-crosslinked polymer particles were coated with 124.5 kg of a 2.4% strength by weight aqueous polyethylene glycol solution (polyethylene glycol with an average molar mass of 400 g/mol).
  • polymer gel B The polymer gel obtained in this way (polymer gel B) was immediately dried together with the polymer gel A in a circulating air drying cabinet at 170° C. for 60 minutes. For this purpose, polymer gel A was distributed on a drying tray and then polymer gel B was added. A total of 700 g of polymer gel were dried.
  • the dried polymer gel was crushed using a roller mill and sieved to a particle size of 300 to 600 ⁇ m.
  • the polymer particles were then thermally surface post-crosslinked.
  • the polymer particles were oxazolidone in a food processor with a mixture of 0.088 g of 2-hydroxyethyl-2, 0.088 g of 1,3-propanediol, 1.8 g of 1,2-propanediol, 0.88 g of a 26.8 wt Sprayed aluminum sulfate solution and 3.5 g of water and stirred for one minute.
  • the examples show a significant improvement in absorption speed (vortex) with increasing proportion of polymer gel B.
  • the examples show an improvement in absorption speed (vortex) with increasing proportion of polymer gel B.
  • Examples 9 to 12 show an improvement in absorption speed (vortex) with increasing proportion of polymer gel B.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Dispersion Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

L'invention concerne un procédé de production de particules superabsorbantes post-réticulées thermiquement en surface, le procédé comprenant la polymérisation d'une solution ou suspension monomère, le séchage statique du gel polymère aqueux obtenu, la fragmentation du gel polymère séché, la classification de particules polymères obtenues, des particules polymères trop petites étant séparées en tant que tamisat, le mélange du tamisat séparé avec une solution aqueuse, la solution aqueuse contenant un agent de réticulation, et la réintroduction du gel polymère obtenu à partir du tamisat dans l'étape de séchage statique.
EP21823321.1A 2020-12-16 2021-12-07 Procédé de production de particules superabsorbantes Pending EP4263630A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP20214556 2020-12-16
PCT/EP2021/084567 WO2022128619A1 (fr) 2020-12-16 2021-12-07 Procédé de production de particules superabsorbantes

Publications (1)

Publication Number Publication Date
EP4263630A1 true EP4263630A1 (fr) 2023-10-25

Family

ID=73855069

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21823321.1A Pending EP4263630A1 (fr) 2020-12-16 2021-12-07 Procédé de production de particules superabsorbantes

Country Status (5)

Country Link
US (1) US20240100506A1 (fr)
EP (1) EP4263630A1 (fr)
JP (1) JP2024503203A (fr)
CN (1) CN116568732A (fr)
WO (1) WO2022128619A1 (fr)

Family Cites Families (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6018690B2 (ja) 1981-12-30 1985-05-11 住友精化株式会社 吸水性樹脂の吸水性改良方法
JPS58180233A (ja) 1982-04-19 1983-10-21 Nippon Shokubai Kagaku Kogyo Co Ltd 吸収剤
US4734478A (en) 1984-07-02 1988-03-29 Nippon Shokubai Kagaku Kogyo Co., Ltd. Water absorbing agent
FI90554C (fi) 1987-07-28 1994-02-25 Dai Ichi Kogyo Seiyaku Co Ltd Menetelmä akryylipolymeerigeelin jatkuvaksi valmistamiseksi
WO1990015830A1 (fr) 1989-06-12 1990-12-27 Weyerhaeuser Company Polymere hydrocolloidal
CA2038779A1 (fr) 1990-04-02 1991-10-03 Takumi Hatsuda Methode de production d'un granulat fluide stable
ES2097235T3 (es) 1991-09-03 1997-04-01 Hoechst Celanese Corp Polimero superabsorbente que tiene propiedades de absorcion mejoradas.
DE4138408A1 (de) 1991-11-22 1993-05-27 Cassella Ag Hydrophile, hochquellfaehige hydrogele
JP3045422B2 (ja) 1991-12-18 2000-05-29 株式会社日本触媒 吸水性樹脂の製造方法
DE69312126T2 (de) 1992-03-05 1997-11-06 Nippon Catalytic Chem Ind Verfahren zu Herstellung eines absorbierenden Harzes
GB9208449D0 (en) 1992-04-16 1992-06-03 Dow Deutschland Inc Crosslinked hydrophilic resins and method of preparation
DE69412547T2 (de) 1993-06-18 1999-04-22 Nippon Shokubai Co. Ltd., Osaka Verfahren zur Herstellung eines absorbierenden Harzes
GB9413619D0 (en) * 1994-07-06 1994-08-24 American Colloid Co Method of increasing the size and/or absorption under load of super-absorbent polymers by surface cross-linking
US6133193A (en) 1994-10-26 2000-10-17 Nippon Shokubai Co., Ltd. Absorbent resin composition and method for production thereof
DE19543368C2 (de) 1995-11-21 1998-11-26 Stockhausen Chem Fab Gmbh Wasserabsorbierende Polymere mit verbesserten Eigenschaften, Verfahren zu deren Herstellung und deren Verwendung
DE19646484C2 (de) 1995-11-21 2000-10-19 Stockhausen Chem Fab Gmbh Flüssigkeitsabsorbierende Polymere, Verfahren zu deren Herstellung und deren Verwendung
US6265488B1 (en) 1998-02-24 2001-07-24 Nippon Shokubai Co., Ltd. Production process for water-absorbing agent
US6241928B1 (en) 1998-04-28 2001-06-05 Nippon Shokubai Co., Ltd. Method for production of shaped hydrogel of absorbent resin
US6239230B1 (en) 1999-09-07 2001-05-29 Bask Aktiengesellschaft Surface-treated superabsorbent polymer particles
DE19955861A1 (de) 1999-11-20 2001-05-23 Basf Ag Verfahren zur kontinuierlichen Herstellung von vernetzten feinteiligen gelförmigen Polymerisaten
US6979564B2 (en) 2000-10-20 2005-12-27 Millennium Pharmaceuticals, Inc. 80090, human fucosyltransferase nucleic acid molecules and uses thereof
DE10204938A1 (de) 2002-02-07 2003-08-21 Stockhausen Chem Fab Gmbh Verfahren zur Nachvernetzung im Bereich der Oberfläche von wasserabsorbierenden Polymeren mit beta-Hydroxyalkylamiden
DE10225943A1 (de) 2002-06-11 2004-01-08 Basf Ag Verfahren zur Herstellung von Estern von Polyalkoholen
CA2487030A1 (fr) 2002-06-11 2003-12-18 Basf Aktiengesellschaft (meth)acrylesters de glycerine polyalcoxy
CA2488226A1 (fr) 2002-06-11 2003-12-18 Basf Aktiengesellschaft Esters (meth)acryliques de trimethylolpropane polyalcoxyle
DE10331450A1 (de) 2003-07-10 2005-01-27 Basf Ag (Meth)acrylsäureester monoalkoxilierter Polyole und deren Herstellung
DE10331456A1 (de) 2003-07-10 2005-02-24 Basf Ag (Meth)acrylsäureester alkoxilierter ungesättigter Polyolether und deren Herstellung
DE10355401A1 (de) 2003-11-25 2005-06-30 Basf Ag (Meth)acrylsäureester ungesättigter Aminoalkohole und deren Herstellung
JP5047616B2 (ja) * 2005-03-14 2012-10-10 株式会社日本触媒 吸水剤およびその製造方法
JP5551836B2 (ja) * 2011-11-16 2014-07-16 株式会社日本触媒 ポリアクリル酸（塩）系吸水性樹脂の製造方法
US11465126B2 (en) * 2016-11-16 2022-10-11 Nippon Shokubai Co., Ltd. Method for producing water-absorbent resin powder and production apparatus therefor
WO2019221236A1 (fr) 2018-05-16 2019-11-21 株式会社日本触媒 Poudre de résine absorbant l'eau et son procédé de production
CN112638337B (zh) * 2018-08-01 2023-01-20 巴斯夫欧洲公司 女性卫生吸收制品
WO2020122471A1 (fr) * 2018-12-11 2020-06-18 주식회사 엘지화학 Procédé de production d'un polymère superabsorbant et polymère superabsorbant

Also Published As

Publication number Publication date
US20240100506A1 (en) 2024-03-28
CN116568732A (zh) 2023-08-08
JP2024503203A (ja) 2024-01-25
WO2022128619A1 (fr) 2022-06-23

Similar Documents

Publication Publication Date Title
EP2411422B2 (fr) Procédé de production de particules polymères hydrophiles à post-réticulation superficielle
EP2307062B2 (fr) Procédé pour produire des particules polymères hydrophiles
EP3497141B1 (fr) Procédé de production de superabsorbant
EP2922580A2 (fr) Procédé de préparation de super-absorbants à base de matières premières renouvelables
EP2291416A1 (fr) Procédé de préparation en continu de particules polymères absorbant l'eau
EP2870183B2 (fr) Procédé de production de particules polymères absorbant l'eau, à propriétés améliorées
EP2814854B1 (fr) Particules polymères hydrophiles présentant une vitesse de gonflement et une perméabilité élevées
EP4626962A1 (fr) Procédé de production de particules superabsorbantes de couleur stable
EP3914400B1 (fr) Procédé de production de particules superabsorbantes
EP4263630A1 (fr) Procédé de production de particules superabsorbantes
EP3914628B1 (fr) Procédé de production de particules superabsorbantes
WO2020151972A1 (fr) Procédé de production de particules superabsorbantes
EP2714104B1 (fr) Procédé de production de particules polymères absorbant l'eau
WO2024126174A1 (fr) Procédé de production de superabsorbants
WO2025040440A1 (fr) Procédé de post-réticulation de surface thermique de superabsorbants
WO2025040441A1 (fr) Procédé de post-réticulation de surface thermique de superabsorbeurs
EP2861631B1 (fr) Procédé de fabrication de particules de polymère absorbant l'eau dans un réacteur de polymérisation comprenant au moins deux arbres rotatifs parallèles
WO2025061557A1 (fr) Procédé de post-réticulation de surface thermique de superabsorbants
WO2024146792A1 (fr) Procede de production de superabsorbants
WO2024132670A1 (fr) Procédé de production de superabsorbants
WO2024132671A1 (fr) Procédé de production de superabsorbants
WO2025040439A1 (fr) Procédé de postréticulation de surface thermique de superabsorbants
EP3755730B1 (fr) Procédé de production de particules superabsorbantes
WO2025040438A1 (fr) Procédé de post-réticulation de surface thermique de polymères superabsorbants
EP2714103B1 (fr) Procédé de production continue de particules polymères hydroabsorbantes

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20230717

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)