Green environmental protection is the inevitable trend of fo
Food packaging film is becoming more and more important in commodity packaging because it has excellent performance to protect food safety efficiently, and its high transparency can effectively beautify the packaging. In order to meet the changing external environment and the needs of different consumers, many enterprises at home and abroad have increased the research and development of food packaging film. First of all, let's take a look at the classification:
1. general packaging film
At present, the commonly used food packaging films include PVA coating barrier film, biaxial tensile polypropylene film, biaxially stretched polyester film, nylon film, cast film, aluminum plating film and so on. These films are widely used because of their excellent properties, good transparency, high tensile strength, resistance to gas and water resistance, low production cost and wide application.
2. antibacterial food packaging film
Antibacterial food packaging film is a kind of functional thin film which has the ability to inhibit or kill surface bacteria. According to the form of antibacterial, it can be divided into two kinds: direct antibacterial and indirect antibacterial. Direct antibacterial activities can be carried out through direct contact with food containing antibacterial ingredients, and indirect antibacterial, mainly by adding some substances that can regulate the microenvironment in the packaging, or control the growth of microorganism using the selective permeability of packaging materials, such as the atmosphere packaging film.
3. edible packaging film
Edible packaging film is a film made of edible materials, mainly natural macromolecules such as lipids, proteins and polysaccharides, adding edible plasticizers and crosslinker, and blending through physical effects through different processing techniques. According to the characteristics of the main raw materials used, edible film can be divided into four major categories: sugar edible film, protein edible film, lipid edible film, compound edible film. For edible functional film, it has been widely used in daily life, such as the familiar sticky rice paper used on candy packaging, and the packaging cup of corn ice-cream, which are typical edible packaging. Compared with synthetic packaging materials, edible films can be biodegraded without any pollution. With the enhancement of people's awareness of environmental protection, edible film has rapidly become a research hotspot in food packaging field, and has achieved certain results.
4. Degradable packaging film
This kind of film mainly solves the difficulty of recovery of some non degradable packaging materials, the buried underground will destroy the soil structure, and the incineration treatment will also cause the problem of air pollution caused by toxic gases. According to the degradation mechanism, they are mainly divided into photodegradable packaging film and biodegradable packaging film.
Degradable films are widely studied nowadays because of meeting the requirements of environmental protection. Many new types of degradable environmental protection materials have been developed, such as polylactic acid made from the raw material of renewable plant resources, a kind of environmentally friendly plastics synthesized with carbon dioxide and propylene oxide as raw materials. Propyl carbonate and chitosan obtained by deacetylation of chitin in nature. The properties of these materials are reduced, and the optical properties, transparency and surface gloss are also degraded completely. It not only satisfies the high transparency of the packaging film, but also plays an active role in improving the environment, and has a great application prospect.
5. nano composite packaging film
Nanocomposite film is a composite film material formed by the dimension size of the nano scale component inlaid in different matrix, which has the advantages of both traditional and modern nanomaterials. Due to the surface effect, volume effect and size effect caused by its special structure, the properties of the nanocomposite films have made their optical properties, mechanical properties, antibacterial properties and barrier properties not available in the conventional materials, so that they are widely used in food packaging, not only to meet the delay. The requirement of the shelf life of long food is also able to monitor the quality change of food in the package.
But at the same time, food packaging film has more stringent requirements on the safety of packaging materials. It needs corresponding related standards and testing procedures. Although some measures have been taken at home and abroad, there are still a lot of shortcomings. Abroad recently developed and developed the use of plasma surface treatment technology on PET, BOPP and other substrates, such as SiOx, AlOx and other inorganic oxide coatings, to get high barrier film. The silicon coating has relative stability to temperature and is suitable for high temperature cooking and sterilization food packaging. Degradable film, edible film and water-soluble membrane are all the green packaging products developed in the world in recent years. The research on natural macromolecular polymers such as lipids, proteins and carbohydrates has also developed rapidly.
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