How to Prepare Hydrophilic Polyurethane Foam? — Preparation by Impregnation Method

By immersing conventional open-cell polyurethane soft foam into a solution of hydrophilic polymers dissolved in water or organic solvents, hydrophilic polyurethane foam with water-absorbing properties can be obtained after drying. Common hydrophilic polymers include hydroxypropyl cellulose, methylcellulose, acrylic copolymer resins, and polyvinyl alcohol (PVA). To further enhance the water absorption performance of the foam, compression methods can also be used.

Preparation

Water-absorbing polyurethane foam can be produced by foaming with standard raw materials such as polyether polyols, polyisocyanates, blowing agents, catalysts, and foam stabilizers. The resulting foam is then impregnated with a hydrophilic polymer solution and formed under compression to obtain the final hydrophilic foam. This type of foam is suitable for use in toys, cosmetics, cleaning products, sanitary towels, medical and hygiene products, wild vegetable preservatives, agricultural and forestry water-retaining agents, moisturizers, and absorbents for food packaging.

Raw Materials

Common polyether, isocyanates, cross-linking agents, foam stabilizers, catalysts, and hydrophilic resins (e.g., polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), methylcellulose (MC))

Formulation I

Impregnation Process

Immerse the polyurethane foam in a 2% aqueous PVA solution, then compress the foam in the Y-axis direction at 5 kg/cm² pressure. Dry overnight in a hot air oven at 80 °C to obtain hydrophilic polyurethane foam.

Performance

Formulation II

Performance

For the preparation method by adding water-absorbent resin, click here to read.

For the preparation method by introducing hydrophilic segments, click here to read.