Generally, it has high physical strength and certain water resistance. According to the characteristics of goods, packaging paper has corresponding special properties. In packaging paper, the bag paper used to package bulk powdery industrial and agricultural raw materials, such as cement and fertilizer, is usually made of 3 ~ 4 layers of paper, so it is also called multi-layer bag paper to distinguish it from other bag papers used to package light and fine commodities.
This kind of wrapping paper mainly requires high strength, heavy load resistance, impact resistance and proper air permeability. There are the most varieties and specifications of food packaging paper. It is divided into two categories: inner packaging and outer packaging. Direct contact with food is called inner wrapping paper, which is mainly required to be clean and germ-free, and has the characteristics of moisture-proof, oil-proof, anti-sticking and mildew-proof.
Outer wrapping paper is mainly used to beautify and protect goods. In addition to a certain physical strength, it also needs to be clean and beautiful, suitable for printing multi-color commodity patterns and words. The packaging paper of liquid drinks such as milk and vegetable juice must also have excellent impermeability. In order to meet the needs of long-term preservation and fresh-keeping, a special soft packaging paper for beverages was developed, which was composed of paper and metal film, paper and plastic and metal film.