초록 ▼

Among other things, a process for producing an agglomerated superabsorbent polymer particle and an agglomerated superabsorbent polymer particle are disclosed. The process comprises the steps of: (A) bringing superabsorbent polymer fine particles having at least about 40 wt. %, a particle size of les

Among other things, a process for producing an agglomerated superabsorbent polymer particle and an agglomerated superabsorbent polymer particle are disclosed. The process comprises the steps of: (A) bringing superabsorbent polymer fine particles having at least about 40 wt. %, a particle size of less than about 150 μm into contact with a fluid comprising to more than about 10 wt. % a cross-linkable, uncrosslinked polymer based on polymerized, ethylenically unsaturated, acid group-bearing monomers or salts thereof; and(B) cross-linking the uncrosslinked polymer by heating the superabsorbent polymer fine particles and the fluid to a temperature from about 20 to about 300° C., so that the cross-linkable, uncrosslinked polymer at least partially crosslinks.

대표청구항 ▼

1. A process for producing an agglomerated superabsorbent polymer particle comprising less than about 10 wt. %, based on the total weight of the agglomerated superabsorbent polymer particle, of superabsorbent polymer fine particles having a particle size of less than about 150 μm, said process steps

1. A process for producing an agglomerated superabsorbent polymer particle comprising less than about 10 wt. %, based on the total weight of the agglomerated superabsorbent polymer particle, of superabsorbent polymer fine particles having a particle size of less than about 150 μm, said process steps comprising: (A) supplying (i) post crosslinked superabsorbent polymer fine particles having at least about 40 wt. %, based on the total weight of the agglomerated superabsorbent polymer particle, a particle size of less than about 150 μm(B) spraying or mixing the post crosslinked superabsorbent polymer fine particles of (A) with a fluid comprising a) more than about 18 wt. % to about 55 wt %, based on the total weight of the fluid, of a cross-linkable, uncross-linked polyacrylate solution neutralized to from about 45 mol % to about 55 mole %, which polyacrylate solution is based on polymerized, polyacrylic acid or salts thereof to at least about 20 wt. %, based on the total weight of the cross-linkable, uncrosslinked polymer, and b) a crosslinker;(C) heating the post crosslinked superabsorbent polymer fine particles brought into contact with the fluid of step (B) to a temperature within a range from about 100 to about 200° C., so that the cross-linkable, uncross-linked polymer at least partially crosslinks to form agglomerated superabsorbent polymer particles having a particle size of more than about 850 μm; and(D) comminuting the agglomerated superabsorbent polymer particles of step (C) to produce at least about 80 wt. % of the agglomerated superabsorbent polymer particles of step (C) to have a particle size within the range of about 200 μm to about 900 μm;wherein (a) the cross-linkable, uncross-linked polyacrylate solution comprises, besides the polymerized, ethylenically unsaturated, acid groups-bearing monomers, further polymerized, ethylenically unsaturated monomers (M) capable of reacting with polymerized acid group-bearing monomers in a condensation reaction, in an addition reaction, or in a ring opening reaction, and(b) wherein the agglomerated superabsorbent polymer particle has less than about 10 wt. %, based on the total weight of the agglomerated superabsorbent polymer particle, of superabsorbent polymer fine particle size of less than about 150 μm. 2. The process according to claim 1, wherein the post crosslinked superabsorbent polymer fine particles comprise: (α1) from about 0.1 wt. % to about 99.999 wt. % of polymerized, ethylenically unsaturated, acidic group-containing monomers or salts thereof, or polymerized, ethylenically unsaturated monomers containing a protonated or a quaternary nitrogen, or mixtures thereof, wherein mixtures comprising at least ethylenically unsaturated, acidic groups-containing monomers, preferably acrylic acid, are one aspect;(α2) from 0 wt % to about 70 wt % of polymerized, ethylenically unsaturated monomers which can be co-polymerized with (α1);(α3) from about 0.001 wt. % to about 10 wt. % of one or more cross-linkers;(α4) from 0 wt % to about 30 wt % of water-soluble polymers;(α5) from 0.3 wt % to about 5 wt % of hased on the weight of the superabsorbent polymer fine particles of a post crosslinker;(α6) from 0 wt % to about 20 wt % of one or more auxiliaries, wherein the sum of the component weights (α1) to (α6) amounts to about 100 wt. %. 3. The process according to claim 1, wherein the cross-linkable, uncrosslinked polyacrylate solution comprises a weight average molecular weight of more than about 8000 g/mol. 4. The process according to claim 1, wherein the monomer (M) comprises a polymerized, ethylenically unsaturated conversion product of saturated aliphatic, cycloaliphatic, aromatic alcohols, amines or thiols with ethylenically unsaturated carboxylic acid, carboxylic acid derivatives or allyl halides. 5. The process according to claim 1, wherein the postcrosslinker is ethylene carbonate. 6. The process according to claim 1, wherein the bringing into contact of the superabsorbent polymer fine particles with the fluid occurs in the presence of an effect material comprising a polysaccharide or a polyalkylether polyol or a silicon-oxygen-comprising compound or a mixture of at least two thereof. 7. The process according to claim 6, wherein the effect material comprises a zeolite. 8. The process according to claim 1, wherein the bringing into contact occurs in a fluidized bed. 9. An agglomerated superabsorbent polymer particle obtained by a process according to claim 1. 10. The agglomerated superabsorbent polymer particles made according to the process of claim 1, wherein the agglomerated superabsorbent polymer particles have at least one of the following properties: a1) a particle size distribution, whereby at least about 90 wt. % of the agglomerated superabsorbent polymer particles of step (C) to have a particle size within the range of about 200 μm to about 900 μm;a2) a Centrifuge Retention Capacity (CRC) of at least about 5 g/g;a3) an Absorption Against Pressure (AAP) at about 0.7 psi of at least about 5 g/g;a4) a water-soluble polymer content of less than about 25 wt. % after about 16 hours extraction.