The hottest plastic flexible packaging materials

2022-08-14
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Plastic flexible packaging materials (Part 2)

III. sterile and antibacterial plastic packaging materials

sterile packaging can retain the original nutritional components and flavor of food to the greatest extent under sterile conditions without adding preservatives at room temperature. It can prolong the shelf life and facilitate transportation and storage. Aseptic packaging is mainly used in food, high seasoning, medicine, cosmetics and other fields. The flexible packaging materials used are paper, plastic, aluminum-plastic composite films, multi-layer co extruded sterile packaging sheets containing high barrier plastics, etc

antibacterial plastic packaging materials give certain antibacterial properties to plastic packaging materials. Now a brand-new masterbatch with silver ion as inorganic antibacterial agent has been developed. Silver ion has significant antibacterial effect, which is characterized by long-lasting antibacterial effect, will not be high due to gasification and migration, and will not pollute the environment. The film made from the added masterbatch containing silver ion (content 1%-3%) or the container with a layer of this film on the surface has been tested. It has been shown that the film containing 1% silver ion masterbatch can completely kill the bacteria that will cause food poisoning within days without nutrient source, and is widely used in the packaging of cooked meat, aquatic products and liquid food

IV. high heat-resistant plastic packaging materials

heat resistant plastic flexible packaging materials used to be resistant to cooking and sterilization, which meet the packaging requirements of cooking and sterilization. Under the condition of 12O ℃, min cooking and sterilization or heating, there is no obvious change in appearance, shape and quality, and the packaged food will not produce container damage, content leakage, microbial secondary pollution, light and heat deterioration during storage. Cooking bags are mostly made of multilayer composite cooking films with shading aluminum foil as the middle layer, high barrier plastics PA and pet as the outer layer, and heat sealing PE and PP as the inner layer. Some new multilayer composites containing high barrier materials such as EVOH, PVDC, MXD6 and silicon oxide evaporation film are also increasingly used

with the increasing popularity of electromagnetic cookers and microwave ovens, there is an increasing demand for packaging containers suitable for electromagnetic cookers and microwave ovens. The requirements of electromagnetic cookers and microwave ovens for packaging materials are that they are not significantly deformed, damaged, and the contents (additives) are not volatile under high temperature. In particular, the heating characteristics of microwave ovens do not allow the packaging materials to contain metal materials, which limits the use of cooking bags with aluminum foil as the middle layer and PE and PP as the inner layer. Therefore, now multi-layer composite materials filled with PP and inorganic substances and packaging containers made of crystalline polyester (CPET) sheets are mostly used. New heat-resistant packaging materials with higher temperature resistance, such as polysulfone film, polyetherimide, poly (4-methylpentene) (TPX)/paperboard, have also been developed. They can withstand temperatures above 180 ℃, which is enough to meet the requirements of electromagnetic ovens and microwave ovens for packaging materials

v. special functional materials

functional packaging materials: other flexible packaging materials with special functions include materials with relatively perfect composition of moisture absorption, deodorization, deodorization and static resistance, such as electricity, rust prevention, UV barrier, release or adsorption of volatile gases, convenience (easy to open and seal) and edible. For example, the film prepared by adding iron to PE, PP and PVC or activated carbon and zeolite has the effect of removing ammonia, mercaptan, hydrogen sulfide, dimethylamine and other malodor. It is suitable for packaging agricultural and sideline products, aquatic products, fresh food and so on with special smell, and will not cross smell. It is also suitable for garbage bags and so on

VI. nanocomposite packaging materials

nanotechnology is a high-tech science and technology rising in recent years. Polymer based nanocomposites (pnmc) are the most studied nanocomposite packaging materials. Commonly used polymers include PA, PP, PVC, pet, etc. The plasticity, wear resistance, hardness and strength of nanocomposite plastic packaging materials have been significantly improved and enhanced. Compared with ordinary composite PA packaging materials, the PA6 nanocomposite packaging materials first developed by Japan have increased the tensile strength and tensile modulus by 110MPa and 2.1gpa respectively, increased the thermal deformation temperature to 150%, and greatly reduced the coefficient of thermal expansion and water absorption

at present, the development trend of the newly developed plastic packaging film at home and abroad is towards the direction of high performance, non-toxic and harmless, green environmental protection, high quality and low price, and convenient use. Among them, flexible packaging materials have been further developed from food packaging in the past to non food packaging fields such as industrial packaging, pharmaceutical packaging, building materials packaging, cosmetics packaging, etc. their scope of use and consumption will be more and more new. Materials will be based on enterprises, and scientific and technological innovation system will be established more and more.

source: Guangdong printing, 2005, issue 1, author: Duan Jun

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