Water absorbing material and manufacturing method thereof
US-2015360202-A1 · Dec 17, 2015 · US
Process for producing water-absorbing polymer particles in a polymerization reactor with at least two axially parallel rotating shafts
US9248429B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9248429-B2 |
| Application number | US-201313915927-A |
| Country | US |
| Kind code | B2 |
| Filing date | Jun 12, 2013 |
| Priority date | Jun 13, 2012 |
| Publication date | Feb 2, 2016 |
| Grant date | Feb 2, 2016 |
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Abstract
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A process for producing water-absorbing polymer particles by polymerizing an aqueous monomer solution in a polymerization reactor with at least two axially parallel rotating shafts, wherein the polymerization is performed in the presence of an inert gas and under positive pressure.
First claim
Opening claim text (preview).
The invention claimed is: 1. A process for producing water-absorbing polymer particles by polymerizing a monomer solution or suspension comprising a) an ethylenically unsaturated monomer which bears an acid group and may be at least partly neutralized, b) at least one crosslinker, c) at least one initiator, d) at least one ethylenically unsaturated monomer copolymerizable with the monomer mentioned under a), and e) optionally one or more water-soluble polymer, in a polymerization reactor with at least two axially parallel rotating shafts, which comprises performing the polymerization in the presence of an inert gas and under a positive pressure from 15 to 500 mbar higher than ambient pressure. 2. The process according to claim 1 , wherein the inert gas is nitrogen. 3. The process according to claim 1 , wherein the inert gas comprises less than 0.0005% by volume of oxygen. 4. The process according to claim 1 , wherein the positive pressure in the polymerization reactor is from 15 to 50 mbar. 5. The process according to claim 1 , wherein the inert gas flows continuously through the polymerization reactor. 6. The process according to claim 1 , wherein monomer a) is acrylic acid partly neutralized to an extent of at least 50 mol %. 7. The process according to claim 1 , wherein monomer a) has been neutralized to an extent of 25 to 85 mol %. 8. The process according to claim 1 , wherein the monomer solution comprises from 0.05 to 1.5% by weight of crosslinker b), based on the unneutralized monomer a). 9. The process according to claim 1 , wherein the water-absorbing polymer particles are additionally surface postcrosslinked.
Assignees
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Classifications
Cross-linked polymers · CPC title
characterised by special features of the polymerisation apparatus used · CPC title
- B01J20/30Primary
Processes for preparing, regenerating, or reactivating · CPC title
Superabsorbents · CPC title
Chemistry & Metallurgy · mapped topic
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Frequently asked questions
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- What does patent US9248429B2 cover?
- A process for producing water-absorbing polymer particles by polymerizing an aqueous monomer solution in a polymerization reactor with at least two axially parallel rotating shafts, wherein the polymerization is performed in the presence of an inert gas and under positive pressure.
- Who is the assignee on this patent?
- Basf Se
- What technology area does this patent fall under?
- Primary CPC classification B01J20/30. Mapped technology areas include Operations & Transport.
- When was this patent published?
- Publication date Tue Feb 02 2016 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 8 related publications on this page (citations in our corpus or others sharing the same primary CPC).