Tech Briefs

Film-Forming, Self- Crosslinking, Aqueous Superabsorbent Coating

This air-curable material absorbs and holds liquids, vapors, and proteins for applications in healthcare, wound care, packaging, textiles, and engineering.

Aqueous Superabsorbent Coating (ASC) technology is a liquid polymer solution that dries to form an absorbent film. It can absorb up to 40 g/g by weight of water, depending on the chemistry used, and can absorb water vapor from the air up to 70% by weight. Tests have demonstrated a greater absorbency of fluids containing proteins than cross-linked sodium polyacrylates (ASC 8-10g/g versus SAP 6g/g). The material can be “dried” after hydrolysis with exposure to air at moderate temperature.

ASC technology has broad application in desiccants, where its unique features of transparency and permeability make it possible to place desiccants where they have not been able to be used before. The final coating may be transparent, gas permeable, and lubricious when wet. At higher coat weights, ASC forms hydrogels on surfaces that can be used as lubricious coatings, or as a release agent for other additives.

ASC can be applied using various techniques to a range of materials and substrates to absorb condensed or evaporated fluids. Application methods include spray, printing, roll-to-roll, screen, slot, or dip coating techniques. ASC is delivered as a liquid suspension that, when dried, self-crosslinks to form a superabsorbent film coating that can absorb many times its own weight of water. Water vapor, bodily fluids, and other aqueous solutions may also be absorbed by the coating. Tests show good adhesion to a wide range of substrates, such as glass, metals, and cellulosics.

A range of related coating chemistries has been reduced to practice, including cationic and anionic. ASC can be cured at ambient/room temperatures or accelerated with heat or microwave energy.

This technology was developed by Kimberly-Clark Corporation and is offered by yet2.com. For more information, view the yet2.com TechPak at http://info.hotims.com/45609-128.