Food biodegradable packaging biodegradable materials are currently mainly divided into four categories, PLA (polylactic acid), PBS (polyester), PBAT (polyester), PHA (polyhydroxyalkanoate).
1. Eco-friendly food packaging biodegradable material: PLA
PLA: It is one of the most common degradable plastics. It is a polymer obtained by polymerizing lactic acid as the main raw material. The production process of PLA, a biodegradable material for eco-friendly food packaging, is pollution-free, and the product is biodegradable. After use, PLA can be degraded into carbon dioxide and water by composting at a temperature higher than 55°C or under the action of oxygen enrichment and microorganisms, so as to realize the biodegradation in nature. The material cycle will not have an impact on the environment. At present, the production of polylactic acid mainly adopts the lactide ring-opening polymerization process to dehydrate lactic acid to form oligomers, then depolymerize to form lactide, and then ring-opening polymerization to obtain polylactic acid. PLA also has reliable biosafety, biodegradability, good mechanical properties and ease of processing, and is widely used in packaging like pla tablewares, textile industry, agricultural mulch and biomedical polymers and other industries. One of the best degradable materials for market applications. PLA has a relatively low cost among biodegradable plastics, and the consumption of PLA ranks at the forefront.
2. Eco-friendly food packaging biodegradable materials: PBS
PBS: It is formed by the condensation polymerization of succinic acid and 1,4-butanediol, and the raw material source is the fermentation of petroleum or biological resources. Eco-friendly food packaging biodegradable material PBS is easily decomposed into carbon dioxide and water by various microorganisms or enzymes in nature, and has good biocompatibility and bioabsorbability, as well as good heat resistance. PBS can be used in packaging films, tableware, foam packaging materials, daily necessities bottles, medicine bottles, agricultural films, pesticides and chemical fertilizer slow-release materials and other fields. Due to the limited raw materials of succinic acid, the derivatives of PBS, PBAT and PBSA, were produced in compliance with them, and their performance was basically similar to that of PBS, but the processing performance was not as good as that of PBS.
3. Eco-friendly food packaging biodegradable materials: PBAT
PBAT: belongs to thermoplastic degradable plastics, generally using aliphatic acids and butanediol as raw materials, and produced by petrochemical or biological fermentation. It has good ductility and elongation at break, as well as good heat resistance and impact performance. Due to its good film-forming properties and easy film blowing, PBAT is widely used in the field of disposable packaging films and agricultural films. The disadvantage of PBAT is that the degradation conditions are relatively harsh.
4. Eco-friendly food packaging biodegradable materials: PHA
PHA: PHAs degradable plastics include polyhydroxyalkanoate (PHA), poly3-hydroxybutyrate (PHB) and other categories. PHA has a special degradation method. After use, PHA can be completely degraded into β- Hydroxybutyric acid, carbon dioxide and water. PHAs degradable plastics have high heat distortion temperature and good biocompatibility, but have narrow processing temperature range, poor thermal stability, high brittleness, and unstable production quality. They can be used in disposable products, medical equipment surgical gowns, packaging bags and biodegradable compostable shopping bags, medical sutures, repair devices, bandages, orthopedic needles, anti-adhesion films and stents, etc.
Degradable materials have their advantages in performance, practicability, degradability and safety. In terms of performance, degradable plastics can reach or exceed the performance of traditional plastics in certain specific fields; in terms of practicality, degradable plastics have similar application performance and hygienic performance to similar traditional plastics; in terms of degradability, degradable plastics can be degraded quickly in the natural environment after use, and become fragments or non-toxic gases that are easily used by the environment, reducing the impact on the environment; in terms of safety, the substances produced or left in the degradation process of environmentally friendly food packaging are harmless to the environment and will not affect the survival of humans and other organisms.