Superabsorbent polymer with high permeability
First Claim
Patent Images
1. A superabsorbent polymer comprising a) from about 55 to about 99.9 wt. % of polymerizable unsaturated acid group containing monomers;
- b) from about 0.001 to about 5.0 wt. % of internal crosslinking agent;
c) from about 0.001 to about 5.0 wt. % of surface crosslinking agent applied to the particle surface;
d) from 0 to about 5 wt. % of a penetration modifier immediately before, during or immediately after the surface crosslinking step;
e) from 0 to about. 5 wt. % of a multivalent metal salt on the surface;
f) from 0 to 2 wt % of a surfactant on the surface;
g) from about 0.01 to about 5 wt % of an insoluble, inorganic powder; and
h) from about 0.01 to 5 wt % of a thermoplastic polymer having a thermoplastic melt temperature wherein the thermoplastic polymer is applied on the particle surface coincident with or followed by a temperature at least about the thermoplastic melt temperature or greater, wherein the composition has a degree of neutralization of more than about 25%;
having the characteristics of centrifuge retention capacity of about 25 g/g or more;
a gel bed permeability I of about 500×
10−
9 cm2 or more;
or a gel bed permeability II of about 300×
10−
9 cm2 or more.
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0 Petitions
Accused Products
Abstract
The invention relates to absorptive, crosslinked polymers which are based on partly neutralized, monoethylenically unsaturated monomers carrying acid groups wherein the absorptive crosslinked polymer may be coated with a thermoplastic polymer, and have improved properties, in particular in respect of their capacity for transportation of liquids in the swollen state, and which has a high gel bed permeability and high centrifuge retention capacity.
104 Citations
19 Claims
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1. A superabsorbent polymer comprising
a) from about 55 to about 99.9 wt. % of polymerizable unsaturated acid group containing monomers; -
b) from about 0.001 to about 5.0 wt. % of internal crosslinking agent;
c) from about 0.001 to about 5.0 wt. % of surface crosslinking agent applied to the particle surface;
d) from 0 to about 5 wt. % of a penetration modifier immediately before, during or immediately after the surface crosslinking step;
e) from 0 to about. 5 wt. % of a multivalent metal salt on the surface;
f) from 0 to 2 wt % of a surfactant on the surface;
g) from about 0.01 to about 5 wt % of an insoluble, inorganic powder; and
h) from about 0.01 to 5 wt % of a thermoplastic polymer having a thermoplastic melt temperature wherein the thermoplastic polymer is applied on the particle surface coincident with or followed by a temperature at least about the thermoplastic melt temperature or greater, wherein the composition has a degree of neutralization of more than about 25%;
having the characteristics of centrifuge retention capacity of about 25 g/g or more;
a gel bed permeability I of about 500×
10−
9 cm2 or more;
or a gel bed permeability II of about 300×
10−
9 cm2 or more. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19)
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11. A superabsorbent polymer comprising
a) from about 55 to about 99.9 wt. % of polymerizable unsaturated acid group containing monomers; -
b) from about 0.001 to about 5.0 wt. % of internal crosslinking agent;
c) from about 0.001 to about 5.0 wt. % of surface crosslinking agent applied to the particle surface;
d) from 0 to about 5 wt. % of a penetration modifier immediately before, during or immediately after the surface crosslinking step;
e) from 0 to about 5 wt. % of a multivalent metal salt on the surface;
f) from 0 to 2 wt % of a surfactant on the surface;
g) from about 0.01 to 5 wt % of a thermoplastic polymer having a thermoplastic melt temperature wherein the thermoplastic polymer is applied on the particle surface coincident with or followed by a temperature at least about the thermoplastic melt temperature or greater, wherein the composition has a degree of neutralization of more than about 25%;
having the characteristics of centrifuge retention capacity of about 25 g/g or more;
a gel bed permeability I of about 200×
10−
9 cm2 or more;
or a gel bed permeability II of about 150×
10−
9 cm2 or more.
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Specification
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Current AssigneeEvonik Superabsorber LLC
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Original AssigneeStockhausen Incorporated
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InventorsLoeker, Frank, Bremus, Heinz, Mcintosh, Stan, Smith, Scott J.
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current525/244
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CPC Class CodesB01J 20/267 Cross-linked polymersC08F 220/06 Acrylic acid; Methacrylic a...C08J 2325/04 Homopolymers or copolymers ...C08J 3/075 Macromolecular gelsC08J 3/12 Powdering or granulatingC08J 3/126 Polymer particles coated by...C08L 25/04 Homopolymers or copolymers ...
