IP Library Granted Patent US 7,427,650
Granted Patent B2
US 7,427,650 · App. 11/766,399 · Granted Sep 23, 2008

Absorbing structure having improved blocking properties

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Quick Facts
Patent No.
US 7,427,650
App. No.
11/766,399
Granted
Sep 23, 2008
Kind
B2
Abstract

A process for producing an absorbing polymer structure (Pa) including the steps of obtaining a treated absorbing polymer structure (Pb) by increasing the absorption under load at a load of 0.3 or 0.9 psi (AUL) compared to an untreated absorbing polymer structure (Pu) by a first treatment of an outer region of the untreated absorbing polymer structure (Pu) and reducing the AUL compared to the treated polymer structure (Pb) by a second treatment of an outer region of the treated absorbing polymer structure (Pb). Such absorbing polymer structure (Pa) may be used in a composite and may be used in foams, moulded articles, fibers, sheets, films, cables, sealing materials, liquid-absorbing hygiene articles, carriers for plant growth-regulating and fungal growth-regulating agents, packaging materials and soil additives or building materials.

Claims (23)

1. An absorbing polymer composition (Pa) obtained by a process comprising the following steps:

preparing an absorbing polymer comprising the step of polymerizing

(α1) 0.1 to 99.999 wt. % of polymerized, ethylenically unsaturated, acid group-containing monomers or their salts, or polymerized, ethylenically unsaturated monomers containing a protonated or quaternated nitrogen atom, or their mixtures; and

(α2) 0.001 to 10 wt% of a crosslinking agent,

resulting in an untreated dried absorbing polymer structure (Pu) having an outer region and an absorption under load (AUL) at a load of 0.3 psi (AUL 0.3 ), and an absorption under load at a load of 0.9 psi (AUL 0.9 ), and having a centrifuge retention capacity (CRC) of from 10 to 100 g/g;

preparing a treated absorbing polymer structure (Pb) comprising the steps of treating the outer region of the untreated absorbing polymer structure (Pu) wherein the (AUL 0.3 ) is increased to at least 25 g/g, and the (AUL 0.9 ) is increased to at least 18 g/g; and further treating the outer surface of the treated absorbing polymer structure (Pb) to make the absorbing polymer composition (Pa) with a coating agent to reduce the (AUL 0.3 ) and the (AUL 0.9 ) values of the treated polymer structure (Pb).

2. An absorbing polymer structure (Pa) comprising:

an untreated dried absorbing polymer structure (Pu) comprising the step of polymerizing

(α1) 0.1 to 99.999 wt. % of polymerized, ethylenically unsaturated, acid group-containing monomers or their salts, or polymerized, ethylenically unsaturated monomers containing a protonated or quatemated nitrogen atom, or their mixtures; and

(α2) 0.001 to 10 wt. % of a crosslinking agent,

wherein said untreated dried absorbing polymer structure (Pu) has an outer region and an absorption under load (AUL) at a load of 0.3 psi (AUL 0.3 ), and an absorption under load at a load of 0.9 psi (AUL 0.9 ), and having a centrifuge retention capacity (CRC) of from 10 to 100 g/g; preparing a treated absorbing polymer structure (Pb) comprising the steps of treating the outer region of the untreated absorbing polymer structure (Pu) wherein the (AUL 0.3 ) is increased to at least 25 g/g, and the (AUL 0.9 ) is increased to at least 18 g/g; and further treating the outer surface of the treated absorbing polymer structure (Pb) with a coating agent to reduce the (AUL 0.3 ), and the (AUL 0.9 ) values of the treated polymer structure (Pb), wherein the treated polymer structure (Pb) has at least one of the following properties:

(β1) a CRC of at least 10 g/g,

(β2) an AUL at a load of 0.3 psi of at least 15 g/g,

(β3) an AUL at a load of 0.9 psi of at least 8 g/g,

(β4) a gel stability in the region of at least 100 sec. at a first measurement before a warming-up and at least 15 sec. at a second measurement after the warming-up, or

(β5) a penetration of at most 15 cm after 2 hours or at most 20 cm after 24 hours, or

(β6) a swelling pressure of at least 400 g,

3. The absorbing polymer structure (Pa) according to claim 2 wherein the absorbing polymer structure (Pa) has an AUL at a load of 0.3 psi of less than 27 g/g and a swelling pressure of at least 400 g.

4. composite comprising:

a substrate; and

an absorbing polymer structure (Pa) according to claim 3 .

5. A process for the production of a composite comprising the steps of bringing in contact with one another an absorbing polymer structure (Pa) of claim 3 , and a substrate, and optionally an auxiliary substance.

6. Foams, moulded articles, fibers, sheets, films, cables, sealing materials, liquid-absorbing hygiene articles, carriers for plant growth-regulating and fungal growth-regulating agents, packaging materials, soil additives or building materials comprising an absorbing polymer structure (Pa) according to claim 3 .

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 20, 2021
From: EVONIK OPERATIONS GMBH
To: EVONIK SUPERABSORBER GMBH
Reel/Frame 057880/0773 →
CHANGE OF NAME Recorded Dec 9, 2019
From: EVONIK DEGUSSA GMBH
To: EVONIK OPERATIONS GMBH
Reel/Frame 051225/0770 →
CHANGE OF NAME Recorded May 15, 2013
From: STOCKHAUSEN GMBH
To: EVONIK STOCKHAUSEN GMBH
Reel/Frame 030416/0806 →
MERGER Recorded May 15, 2013
From: EVONIK STOCKHAUSEN GMBH
To: EVONIK DEGUSSA GMBH
Reel/Frame 030417/0037 →