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Solutions for super absorbent polymers (SAP)

SAP is a water-soluble polymer with a very high absorption capacity. Specialists refer to it as polyacrylate. Thanks to its enormous swelling capacity, a single gram of SAP can absorb up to 1000 grams of water. A baby diaper requires about 13 grams of SAP, while five grams of this polymer suffice for a woman’s sanitary napkin.

Polymerization of refined acrylic acid happen often in belt reactors. The gel contains up to 70% of water and is extruded before feeding on a belt or in a fluidized bed dryer. Bühler is able to supply belt dryers (Aeroglide), size reduction / sifting equipment and pneumatic transports to product silos.

The main area of application for SAP are various sanitary products: diapers for babies and sanitary napkins for incontinence and feminine hygiene. The properties of SAP are also used for the reverse function of that in diapers, namely to dispense water, such as in flower pots and agriculture.

Amid modified polyacrylates are applied for preparation of drinking, cooling, boiler or process water and as flocculent in waste water cleaning. Such additives can be modified cationic, anionic or neutral. The requested particle size distribution is prepared by dry grinding and sifting. Depending on the application it is coarser or finer

History

In the early 1960s, the United States Department of Agriculture (USDA) was conducting work on materials to improve water conservation in soils. They developed a resin based on acrylonitrile polymer with an absorption capacity greater than 400 times its weight. Until the 1980s, water absorbing materials were cellulose or fiber-based products with, at most, an absorption capacity of about 20 times their weight. Today's polyacrylate / polyacrylamide copolymers have an absorption capacity greater than 1,000 times their weight.

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