Packaging Materials Study--Other Functional Packaging Materials (4)

Heat-resistant plastic flexible packaging materials used to be resistant to retort sterilization, to meet the retort sterilization requirements of packaging at 120 °C, 10 to 20 minutes retort sterilization or heating, the appearance of the shape, quality have no significant changes, packaging foods in No damage to the container, leakage of contents, secondary contamination of microorganisms, deterioration of the contents by light and heat, etc. occurred during storage. Basically, a light-blocking aluminum foil is used as an intermediate layer, a high-barrier plastic PA and PET are used as the outer layers, and a heat-sealing PE and PP inner layer multi-layered composite cooking film is used most often for cooking bags. Some new multi-layer composite materials such as EVOH, PVDC, MXD6, and silicon oxide evaporated films containing high barrier materials are also being used.

With the increasing popularity of microwave ovens and microwave ovens, there is an increasing demand for packaging containers suitable for use in induction cookers and microwave ovens. The requirement for packaging materials for induction cookers and microwave ovens is that they should not be deformed or damaged at high temperature, and the contents (additives) should not be volatilized. In particular, the heating characteristics of microwave ovens do not allow metal materials to be included in packaging materials. This limits the The use of aluminum foil as the middle layer, PE, PP as the inner cooking bag. Therefore, a packaging container made of PP, a multilayered composite material in which inorganic matter is filled with PP, and a crystalline polyester (CPET) sheet is often used. New heat-resistant packaging materials that are resistant to higher temperatures, such as polyester films, polyetherimides, and polytetramethylpentene (TPX)/paperboard, have also been developed. They are all capable of resisting temperatures above 180°C. Sufficient to meet the requirements of electromagnetic ovens, microwave ovens for packaging materials.

7. Sterile and Antibacterial Plastic Packaging Materials

Sterile packaging can be aseptic conditions, without adding preservatives, at room temperature to maximize the retention of the original nutrients and flavors of food. The shelf life can be extended for transportation and storage. Aseptic packaging is mainly used in food, condiments, medicine and cosmetics. The flexible packaging materials used are paper, plastic, aluminum-plastic composite films, multi-layer co-extruded aseptic packaging sheets containing high barrier plastics, and the like.

Antibacterial plastic packaging material is to give a certain degree of antibacterial properties of plastic packaging materials, and now has developed a new type of masterbatch containing silver ions as an inorganic antibacterial agent, silver ions have a significant antibacterial effect, characterized by long-lasting antibacterial effect It will not be high due to gasification and migration and will not pollute the environment. A thin film prepared by adding a silver ion-containing master batch (a content of 1% to 3%) or a container coated with a layer of this thin film on the surface shows that in the case of a non-nutrient source, a 1% silver ion mother was used. The film of the material can completely kill the bacteria that can cause food poisoning within 1 to 2 days, and is widely used for packaging of cooked meat, aquatic products and liquid foods. In addition, extracts from certain plants in foreign countries have also been produced as antibacterial films, and these antibacterial films are mainly used for the packaging of newly picked vegetables and fruits.

In short, packaging functional materials is a big scientific category, and it is also a big market. With the deepening of market economy in China, more and more functional materials will appear in the market. At the same time, China's packaging materials industry will also be greatly developed. It is believed that more and better functional materials will serve the society in the future.