Petroleum based packaging materials, such as shopping bags, plastic book covers, document bags, etc., have good durability and low cost, and are widely used in various fields. However, the problem of white pollution caused by plastic products has become increasingly prominent, so the search for biomass based packaging materials has become a hot spot. Paper is widely recognized for its advantages of degradability, regeneration and easy surface modification. However, the inherent hydrophilicity of paper is strong, so how to improve the hydrophobic and waterproof properties of paper and expand its application has become a research hotspot.

The commonly used technologies to improve the hydrophobic and waterproof properties of paper are surface coating, slurry sizing and surface sizing. Polyethylene and polypropylene are often used in commerce to improve the water resistance of paper through film coating technology, such as disposable paper cups, food packaging boxes and bags. In paper making industry, AKD emulsion is often used to improve the water resistance of paper by sizing process, but there are problems such as difficulty in recovering paper and difficult degradation. Surface sizing can give the paper excellent hydrophobic and waterproof properties. Compared with the above paper modification technology, it improves the rolling ability of water droplets on the paper surface, improves the waterproof and durability of the paper, solves the problem of recycling, and can achieve an effect comparable to that of plastics.

Based on the above principles, the functional polymer materials research center of the Institute of physics and chemistry of the Chinese Academy of Sciences proposed a strategy to endow the paper surface with high hydrophobic properties, which is realized by regulating the morphology and properties of cellulose materials. The researchers first prepared hydrophobic flake cellulose with different scales by using the existing technology in the group, and then prepared environmental friendly water-based paper waterproof agent by adjusting the content of different flake cellulose. With the increase of hydrophobic flake cellulose content in waterproof agent, the water contact angle increased first and then decreased. The paper has excellent water resistance and can maintain its original state even after soaking in water for 8 hours.

However, the advantages of the hydrophobic paper can not be fully reflected by the above methods. Therefore, researchers prepared lightweight kraft paper with a weight of 80 g / m2 through the existing technology in the laboratory, and hydrophobically modified it with sheet cellulose based coating. Compared with the existing packaging bags of brand a and brand B on the market, it is found that the packaging paper has excellent mechanical properties and hydrophobic properties at relatively low gram weight. Among them, the transverse and longitudinal wet tensile strength of the paper can reach 1.12 kn / M and 1.81 kn / m, which are increased by 387%, 364% and 918% and 1545% respectively compared with brand a and brand B. The Cobb value of the paper is about 16 g / m2, the water contact angle is up to 140 °, and has excellent hydrophobic and water resistance. In addition, the paper has no obvious change in color before and after modification, and has good printability. This hydrophobic modification of paper provides a simple and efficient way to "replace plastic with paper".