Many things we buy or use in life have flexible packaging materials. For example, a circle of publicity pictures on beverage bottles, plastic paper, plastic film on supermarket purchases, transparent bags coated with electronic products, etc. These things have a common name, called PVC heat shrinkable film.
Heat shrinkable film appeared earlier in Germany in World War II. PVDC was used to package weapons after biaxial stretching to prevent rust. Therefore, heat shrinkable film was used in industrial packaging from the beginning of industrial production, and then heat shrinkable film was used in food packaging.
The development of plastic packaging film industry in China has mainly experienced more than 20 years, during which a certain scale has been formed. The heat shrinkable film industry occupies an important position in the packaging market and plays a positive role in promoting the national economy.
1、 Introduction to heat shrinkable film
Heat shrinkable film, commonly known as shrinkable film, is a film that can shrink greatly after heating, so it can tightly wrap articles and maintain its shape for a long time. The heat shrinkable film is designed based on the principle of tensile orientation of polymer molecular chain and formed by rapid cooling. The physical principle is: after the plastic raw material is heated and plasticized and extruded into the parent film, the polymer is forcibly stretched along the vertical and horizontal directions between the glass transition temperature and the drilling flow temperature, so that the molecular chain of the polymer is oriented along the stretching direction, and then the polymer is suddenly cooled, and the molecular orientation is frozen. When the film is reheated to the "thawing" temperature, due to the stress relaxation caused by molecular motion, the molecules return to their original state and shrink.
Classification of heat shrinkable films
2、 Application of heat shrinkable film
Heat shrinkable film is used in the sales and transportation of various products. Its main function is to stabilize, cover and protect products. At present, the food industry is a large application market of heat shrinkable packaging materials. Heat shrinkable film is widely used in the packaging of all kinds of fast food, lactic acid food, beverage, beer can, all kinds of wine, agricultural and sideline products, local specialties and so on. In the non food field, the application of heat shrinkable film is also increasing, such as cosmetics, daily necessities, pharmaceutical products, electronic products, toys, building materials, handicrafts and so on.
3、 Development history of heat shrinkable film industry
Heat shrinkable film first appeared in Germany during World War II, and then popularized in Western Europe, Japan, the United States and other countries and regions. It has gone through a history of more than 60 years. According to product development and competition, the development process of heat shrinkable film industry can be roughly divided into five stages:
Started with weapons and used for food packaging! One minute to understand heat shrinkable film
4、 Market scale of heat shrinkable film
Heat shrinkable film is developed with the development of its application technology. The two main uses are packaging and labeling. Due to its good transparency, cleaning, anti-theft and convenient use, heat shrinkable film is one of the materials with rapid growth in film packaging; At the same time, due to its good printability, puncture resistance, wear resistance and being close to the uneven object surface during shrinkage, the heat shrinkable film has become the highlight of the label industry.
In 2009, the global heat shrinkable film market was about US $9 billion. Among them, the heat shrinkable film market in the United States is large, with us $1.8 billion in 2009. China has entered the field of heat shrinkable film since the early 1970s. At the beginning, PVC heat shrinkable sleeve film was developed. The production of POF heat shrinkable film began with the introduction of Italian equipment by Zhejiang Zhongda Plastic Co., Ltd. in 1997, and the production capacity was about 1500 tons in 1998. With the development of plastic packaging industry, China's heat shrinkable film products have developed rapidly from variety to quantity. In 2006, the plastic packaging Committee of China Packaging Federation had nearly 20 members of heat shrinkable film enterprises. By 2009, the market scale of heat shrinkable film in China had been close to 8 billion yuan. The market scale of main products of heat shrinkable film in China in 2009 is as follows:
