Method for producing superabsorbers based on renewable raw materials

Patent metadata

Field	Value
Publication number	US-9822197-B2
Application number	US-201314441203-A
Country	US
Kind code	B2
Filing date	Nov 18, 2013
Priority date	Nov 26, 2012
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A process for producing water-absorbing polymer particles, comprising the steps of thermal cracking of bionaphtha in the presence of steam, removing propene and at least some of the propane, gas phase oxidation to give acrylic acid and polymerization to give water-absorbing polymer particles.

First claim

The invention claimed is:

1. A process for producing water-absorbing polymer particles, comprising
i) thermally cracking a naphtha and a bionaphtha from a natural oil and/or fat in the presence of steam to give a mixture comprising propane and propane,
ii) removing propene and at least some of the propane from the mixture obtained in step i),
iii) gas phase oxidation of the propene/propane mixture obtained in step ii) to give acrylic add comprising from 0.02 to 2.0% by weight of propionic acid, and
iv) polymerizing the acrylic add obtained in step iii) and from 0.05 to 1.5% by weight of a crosslinker based on acrylic add to give water-absorbing polymer particles, wherein the acrylic add used in step iv) comprises from 0.02 to 2.0% by weight of propionic add.

2. The process according to claim 1 , wherein the natural oil is palm oil.

3. The process according to claim 1 , wherein the gas phase oxidation in step iii) is performed in two stages.

4. The process according to claim 1 , wherein the acrylic acid used in step iv) comprises 0.03 to 2.0% by weight of propionic acid.

5. The process according to claim 1 , wherein the amount of crosslinker in step iv) is from 0.2 to 0.6% by weight, based on acrylic acid.

6. The process according to claim 1 , wherein the water-absorbing polymer particles are surface postcrosslinked.

7. The process according to claim 1 wherein the water-absorbing polymer particles are coated with an inorganic inert substance.

Assignees

• Basf Se

Inventors

• Hörner Klaus Dieter
• Schröder Jürgen
• Funk Rüdiger
• Wüstefeld Renate

Classifications

• C08J2333/02

  Homopolymers or copolymers of acids; Metal or ammonium salts thereof · CPC title

• A61L15/60 Primary

  Liquid-swellable gel-forming materials, e.g. super-absorbents · CPC title

• C10G2300/1014

  of vegetal origin · CPC title

• C10G3/40

  Thermal non-catalytic treatment · CPC title

• C08F120/06 Primary

  Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof · CPC title