Use of surfactants in drying hydrophilic, highly water-resistant hydrogels

摘要

Improving the drying properties of hydrophilic, highly swellable hydrogels when using contact driers by use of surfactant is new. Preferably heated rollers are used having a contact surface temperature at least 120 degrees C. Nonionic or anionic surfactants are used, having an HLB at least 3, in amounts of 0.01-5 wt. %, referred to solids content of the hydrogel. The hydrogels are based on (co)polymers of hydrophilic monomers, graft (co)polymers of hydrophilic monomers on a suitable graft base, crosslinked cellulose or starch ethers or natural products swellable in aqueous liquids, e.g. guar derivatives, optionally chemically modified.