High barrier packaging materials have been rapidly developed and widely used in packaging industry especially in food packaging industry. It plays a role in food quality preservation, freshness preservation, flavor preservation and shelf life extension. There are various technologies for preserving food, such as vacuum packaging, gas displacement packaging, sealing deoxidizer packaging, food drying packaging, aseptic filling packaging, cooking packaging, liquid thermal filling packaging and so on. In many of these packaging technologies, good barrier plastic packaging materials should be used.
The more common high barrier film materials are as follows:
1. PVDC Materials (Polyvinylidene Chloride)
Polyvinylidene chloride (PVDC) resin, often used as composite material or monomer material and co-extruded film, is the most used high barrier packaging materials. The use of PVDC coated film is particularly large. PVDC coated film is the use of polypropylene (OPP), polyethylene terephthalate (PET) as the base material. Due to the high softening temperature of pure PVDC, the solubility of PVDC is close to its decomposition temperature, and the miscibility with general plasticizer is poor, the heating molding is difficult and difficult to be applied directly. The actual use of PVDC film is mostly the copolymer of vinylidene chloride (VDC) and vinyl chloride (VC), as well as acrylic methylene (MA) copolymerization made of particularly good barrier film.
2. Nylon Packaging Materials
Nylon packaging materials before - straight use "nylon 6". But "nylon 6" air tightness is not ideal. A nylon (MXD6) made from the polycondensation of m-dimethylamine and adipic acid is 10 times more airtight than "nylon 6", while also having good transparency and puncture resistance. Mainly used for high barrier packaging film for high barrier requirements of food flexible packaging. It is also approved by the FDA for food hygiene. Its biggest feature as a film is that the barrier does not fall with the rise of humidity. In Europe, MXD6 nylon is widely used as an alternative to PVDC films due to prominent environmental protection issues.
3. EVOH Materials
EVOH is the most widely used high barrier material.
The film types of this material in addition to the non-tensile type, there are two-way tensile type, aluminum evaporation type, adhesive coating type and so on. Two - way stretching and heat - resistant products for aseptic packaging.
4. Inorganic Oxide Coated Film
PVDC, which is widely used as a high barrier packaging material, has a tendency to be replaced by other packaging materials because its waste will produce HCl when it is burned. For example, the so-called coated film made after the coating of SiOX (silicon oxide) on the film of other substrates has been paid attention to, in addition to the silicon oxide coating film, there are alumina evaporation film. The gas-tight performance of the coating is the same as that of the silicon oxide coating obtained by the same method.
In recent years, multilayer composite, blending, copolymerization and evaporation technologies have developed rapidly. High barrier packaging materials such as vinyl vinyl glycol copolymer (EVOH), polyvinylidene chloride (PVDC), polyamide (PA), polyethylene terephthalate (PET) multilayer composite materials and silicon oxide compound evaporation film have been further developed, especially the following products are more eye-catching: MXD6 polyamide packaging materials; Polyethylene glycol naphthalate (PEN); Silicon oxide evaporation film, etc.
Post time: Mar-09-2023