China uses more than fifteen or sixteen types of plastics for food packaging, such as PE, PP, PS, PET, PA, PVDC, EVA, PVA, EVOH, PVC, and ionic resin. High oxygen barrier plastics include PVA, EVOH, PVDC, PET, and PA; high moisture barrier plastics include PVDC, PP, and PE; radiation-resistant plastics include PS and aromatic nylon; low-temperature resistant plastics include PE, EVA, POET, and PA; those with good oil resistance and mechanical properties include ionic resins, PA, and PET; and those resistant to both high-temperature sterilization and low temperatures include PET and PA. Different plastics have different monomer molecular structures, degrees of polymerization, types and quantities of additives, and therefore different properties. Even the same type of plastic may have different properties depending on the brand.

　　Food packaging holds a very important position in China's packaging industry and is a pillar industry. According to information from the World Packaging Organization (WPO), the global packaging industry's turnover has exceeded US\$500 billion. The composition is as follows: paper and paperboard 32%, plastics 28%, metals 24%, glass 6%, and packaging machinery 5%. Others 5%. The top four packaging materials—paper, plastics, metals, and glass—account for approximately 90% of the food packaging industry's turnover. In Japan, the average annual growth rate of total consumption of various packaging materials is 2.8%, with paper and paperboard accounting for 4.7%, metals 4.9%, glass 3.3%, and plastics 7.1%. This shows that the development of packaging materials is still fastest for plastics, a situation worthy of attention from domestic packaging material manufacturers.

　　Characteristics of Traditional Packaging Materials

　　Paper

　　Paper is a traditional packaging material, and in the Sunny Packaging industrial system, paper and paper packaging containers occupy a very important position. In some developed countries, paper packaging materials account for 40%-50% of the total packaging materials, while in China, it accounts for around 40%. From the development trend, the share of paper packaging materials will become increasingly larger. This is because paper packaging materials have a series of advantages: good processing and printing properties, certain mechanical properties, ease of composite processing, good formability, good hygiene and safety, widely available raw materials, diverse varieties, low cost, easy mass production, relatively light weight, good cushioning, and are widely used. In addition, paper waste can be recycled and biodegraded under natural conditions, preventing white pollution.

　　Plastics

　　Plastics are high-molecular polymers—with resins as the basic component, and various additives added to improve their properties—resulting in high-molecular materials with molecular weights typically above 104-106. Their macromolecules have special structures, giving them a series of special properties, such as chemical inertness, insolubility, and high strength. The use of plastics as packaging materials is an important mark of the development of Sunny Packaging technology. Due to their abundant raw material sources, low cost, and excellent performance, they have become the fastest-growing and most widely used packaging materials in the world in the past 40 years. Plastic packaging materials are widely used in food packaging, gradually replacing traditional packaging materials such as glass, metal, and paper, greatly changing the face of food packaging. It reflects the rich variety and convenient circulation and use of Sunny Packaging food packaging forms, becoming the main packaging material in food packaging sales. However, its disadvantages include certain hygiene and safety issues for some food types, and environmental pollution from the recycling and disposal of packaging waste.

　　Metal

　　Metal materials are long-standing packaging materials, used in food packaging for nearly 200 years. Metal packaging materials and containers are made from metal sheets or foils, processed into various forms of containers for food packaging. Due to their high barrier properties, excellent mechanical properties, and formability, as well as good high and low temperature resistance, thermal conductivity, and surface decoration properties, they have excellent packaging characteristics, packaging effects, and production efficiency. Metal packaging waste is also relatively easy to recycle, resulting in less environmental pollution. It can also be recycled, saving resources and energy. This is especially important in today's promotion of \"green packaging\". Therefore, its application in food packaging is increasingly widespread, making it one of Sunny Packaging's four most important packaging materials. However, due to the poor chemical stability of metal packaging materials and their intolerance to acids and alkalis, especially when packaging highly acidic foods, they are easily corroded. Metal ions can also leach out, affecting food flavor. This limits their use to some extent.

　　Glass

　　Glass is an amorphous material made from quartz, soda ash, limestone, and stabilizers as main raw materials, with clarifying agents, coloring agents, and decolorizing agents added, melted at a controlled temperature, and then cooled and solidified. Glass is an ancient packaging material, used in food packaging for over 3000 years. Due to its inherent advantages, it exhibits significant characteristics as a packaging material: high barrier properties, bright transparency, good chemical stability, and ease of molding. However, glass containers are heavy and easily breakable, a disadvantage that affects its use and development in food packaging, especially given the impact of plastics and composite packaging materials. With the development of glass manufacturing technology, high-strength, lightweight glass materials and products have been developed. Currently, glass accounts for about 10% of the total packaging materials in China, and it remains an important material in food packaging.

　　The continuous research and development of new food packaging materials has given traditional packaging materials more functions, and many new technologies have been widely applied in the food packaging industry. At the same time, various environmentally friendly food packaging materials are being developed, and developed countries are increasing their efforts to develop biodegradable plastic packaging materials to replace traditional plastic products and solve the increasingly serious pollution problem. Moreover, recyclable and comprehensively utilized environmentally friendly packaging boasts high environmental benefits, significant social benefits, and considerable economic benefits. It is a sustainable green packaging and has become an important marketing strategy for businesses.

　　Improvements Needed in Food Packaging Material Development

　　The stability of food bottle materials. The plasticizer incident has caused people to have doubts about whether plastic food bottle packaging will release harmful substances, affecting food safety. In fact, so far there is no conclusion on the harm of plasticizers in food bottles. Therefore, for food bottle manufacturers, proactively improving the stability of food bottle packaging materials is extremely important.

　　The biodegradability of food bottle materials. Because food bottles are widely used, their recycling rate is generally low. A large number of food bottles are difficult to decompose, causing great harm to the soil environment. Plastic bags were banned years ago for this reason. Food bottles need to improve their biodegradability to avoid such policy risks.

　　The heat resistance of food bottles. People's dietary habits often require heating food. If food bottles have good heat resistance, consumers can directly put food in microwaves, which is obviously very convenient for consumers.

　　New Developments in Food Packaging Materials

　　New Food Packaging Paper

　　Insulating paper: It can convert solar energy into thermal energy. Food packaged with this material, when placed in sunlight, can be heated. The heat will only dissipate when the packaging is opened.

　　Anti-corrosion paper: Food packaged with this paper can be stored at a high temperature of 38℃ for 3 weeks without deterioration.

　　Okara paper: It is water-soluble and can be widely used in various food packaging. The main component of this paper is okara (soybean pulp).

　　Fruit residue paper: The main component is apple residue discarded from the food industry. It is mainly used for food packaging. This type of paper is easily degradable after use and can also be recycled to make new paper.

　　Development Trends of Plastic Packaging Materials

　　Plastic packaging mainly improves design, providing more convenience; improves the structure of composite materials to meet more stringent requirements. Future development trends include multilayer composite airtight plastics, functional plastics, and biodegradable plastics are developing rapidly. For example, the United States further polymerizes lactic acid to produce biodegradable plastics; Italy uses corn starch to produce biodegradable plastics. Currently, the United States, France, and Italy have monopolized the multi-billion dollar biodegradable market.

　　China's biodegradable plastic development is also rapid, such as food containers made from starch from potatoes and corn, and "light-bio double-degradable" plastics, but the market share is still not high.

　　Degradable Packaging Materials

　　Due to the increasingly serious "white pollution" caused by the development of plastic packaging materials, people have realized its harm to the human living environment. Therefore, a global wave of "green packaging" has emerged. Germany, the earliest country to advocate for the recycling of packaging materials, formulated a "circular economy" and first implemented a "green tax system"; other countries have also required manufacturers, importers, and retailers to take responsibility for the recycling and remanufacturing of packaging materials.

　　Currently, popular and highly regarded "green packaging" materials in both domestic and international markets include: paper packaging, biodegradable plastic packaging, and bio-based packaging materials, such as "artificial fruit peel", which is a new type of paper whose waste can be recycled. China has already used edible fruit and vegetable liquid preservation films for the preservation of fruit and vegetable packaging. With the rapid development of science and technology and people's increasing attention to environmental protection, packaging is developing towards functionality.

　　Edible Packaging Materials

　　Edible packaging film: Currently, the main research focuses on collagen films made from animal proteins; casings made from animal skins; milk-based preservative films made from whey protein; plant-based preservative films made from soybeans and corn; and moisture-resistant packaging films made from polysaccharides and fats, etc.

　　Edible packaging boxes: The main products are edible products developed using 60% corn, 30% dietary fiber, and 10% other grains as the main raw materials. The dietary fiber in the formula is a functional food base material, beneficial to human health, can remove toxins from the body, and enhance microcirculation function. This product is produced according to food-grade hygiene standards, ensuring that it can be eaten after use and can also be recycled as high-grade feed.