Bio-Based and Fluorine-Free Water- and Oil-Resistant Coating for Paper via Thiol-Ene Click Reaction

Due to the increasingly stringent environmental regulations and the great demand for sustainable materials, fluorine-free water- and oil-resistant coatings for paper have attracted considerable attention in the field of packaging and decoration. In this study, acrylated epoxidized soybean oil (AESO) and pentaerythritol tetrakis(mercaptoacetate) (PETMA) were used as reactants to form a crosslinked film on kraft paper through a UV-initiated thiol-ene click reaction, followed by the spraying of a mixed dispersion of silica (SiO 2 ) and AESO/PETMA solution, and a fluorine-free water- and oil-resistant composite coating on kraft paper was obtained. When the molar ratio of CC bonds of AESO to  SH groups from PETMA was 1:1 and the content of SiO 2 was 20% of the mass of AESO, the water contact angle of the coated paper reached 141°, far higher than that of the uncoated paper at 56.5°. Meanwhile, compared with uncoated paper, the Cobb 60 value of the coated paper sharply decreased from 67.1 to 1.4 g m −2 , demonstrating excellent water resistance. In addition, the oil contact angle of the coated paper also attained 137°, and kit rating of 12/12. The coated paper also exhibited excellent barrier properties to hot castor oil.