Fluorine-free Water- and oil-resistant Coating Composition and Coating Solution, Coating Layer, and Product Comprising the Same

1 . A fluorine-free water- and oil-resistant coating composition comprising:

30 wt % to 97 wt % biodegradable polymer in dry weight;

0.1 wt % to 25 wt % crosslinking agent in dry weight;

25 wt % or less of nanoparticles;

15 wt % or less of plasticizer; and

15 wt % or less of surfactant;

1 wt % or less of antifoaming agent in dry weight,

wherein a coating layer comprising the fluorine-free coating composition has a water resistant property of a Cobb60 value of less than 10 g/m according to the ISO 535 method and a grease resistant property of a kit rating at least 7 according to the TAPPI T-559 method.

2 . The fluorine-free water- and oil-resistant coating composition of claim 1 , wherein the biodegradable polymer is selected from:

chitosan with molecular weight from 20,000 to 2,000,000;

polyvinyl alcohol with molecular weight from 50,000 to 186,000 and a degree of hydrolysis from 90% to 99%;

ethylene-vinyl alcohol copolymer (EVOH) with an ethylene content of less than 10 mol %, a viscosity of 3-35 m·Pas (4 wt % aqueous solution at 20° C.) and a degree of hydrolysis of 90.0-99.5%;

polyhydroxyalkanoates (PHA) with molecular weight from 500 to 1,000,000; or

combination thereof.

3 . The fluorine-free water- and oil-resistant coating composition of claim 1 , wherein the crosslinking agent is selected from citric acid, malic acid, succinic acid, tannic acid, tartaric acid, sodium trimetaphosphate, sodium hexametaphosphate, sodium sulfate or a combination thereof.

4 . The fluorine-free water- and oil-resistant coating composition of claim 1 , wherein the nanoparticle is selected from silicon dioxide, zinc oxide, nano clay or a combination thereof.

5 . The fluorine-free water- and oil-resistant coating composition of claim 4 , wherein the nanoparticle has a particle diameter of 5 nm to 100 nm.

6 . The fluorine-free water- and oil-resistant coating composition of claim 1 , wherein the plasticizer is selected from glycerol, sorbitol, mannitol, xylitol, polyethylene glycol, tributyl citrate or combinations thereof.

7 . The fluorine-free water- and oil-resistant coating composition of claim 1 , wherein the surfactant is selected from a polyoxyethylene sorbitan monolaurate-based surfactant, a polyoxyethylene sorbitan monopalmitate-based surfactant, a polyoxyethylene sorbitan monooleate-based surfactant or combinations thereof.

8 . The fluorine-free water- and oil-resistant coating composition of claim 1 , wherein the antifoaming agent is selected from silicone-based, water-based and oil-based antifoam or combinations thereof.

9 . A fluorine-free coating solution comprising the fluorine-free water- and oil-resistant coating composition of claim 1 and a solvent, wherein the weight ratio of the fluorine-free water- and oil-resistant coating composition to the solvent is 1:1 to 1:20.

10 . The fluorine-free coating solution of claim 8 , wherein the solvent is selected from distilled water, deionized water, methanol, ethanol, propanol, acetic acid, acetone, chloroform, dichloromethane, butyl acetate, ethyl acetate, methyl ethyl ketone, dimethyl carbonate, dimethyl formamide, dimethyl sulfoxide or combinations thereof.

11 . A fluorine-free coating layer comprising the fluorine-free coating solution of claim 8 .

12 . The fluorine-free coating layer of claim 10 , wherein the fluorine-free coating layer is cured by heat treatment of 80° C. to 180° C.

13 . A fluorine-free product comprising the fluorine-free coating layer of claim 10 on a substrate.

14 . The fluorine-free product of claim 13 , wherein the fluorine-free coating layer is applied on the substrate by brush coating, dip coating, bar coating or blade coating.

15 . The fluorine-free product of claim 13 , wherein the substrate is paper, paper pulp container, cardboard or cellulose film.