Fluorine-Free Compound Water- and Oil-Repellent: Preparation and Its Application in Molded Pulp

Molded pulp is considered an alternative to plastic packaging for its low cost, recyclability and non-pollution characteristics. However, the range of its applications has been limited by hydrophilicity and lipophilicity. Presented herein is a facile and straightforward method for the preparation biodegradable water- and oil-repellant for molded pulp. Sodium alginate-based oil repellent and PDMS-based water repellent were prepared by cross-linking and modification. The two were then mixed in various ratios to obtain compound water- and oil-repellent, which was applied to the molded pulp by dip-coating. The coated paper demonstrated excellent oil resistance (with a kit rating of 11/12) and outstanding water resistance (with a water contact angle of 121.9° and water absorption of 25.8%). This novel, eco-friendly, water- and oil-resistant molded pulp coating prepared from biodegradable and food-contactable materials is a potential candidate to replace petroleum-based coatings and has excellent possibilities to be manufactured on a large-scale intended for food and non-food contact applications.