High Resistance Diaphragm - Polyvinylidene Chloride

PVDC resin is often used as a composite material, monomer material, and co extruded film, and is the most commonly used high barrier packaging material, among which PVDC coated film is particularly used in large quantities. PVDC coated films use polypropylene (OPP), polyethylene terephthalate (PET), and other substrates. Due to the high softening temperature of pure PVDC, which is close to its decomposition temperature, and poor solubility with general plasticizers, heating molding is difficult and it is difficult to directly apply. The PVDC films used in practice are mostly copolymers of vinylidene chloride (VDC) and vinyl chloride (VC), as well as films with excellent barrier properties made by copolymerization with methyl acrylate (HA).
The characteristics of PVDC (polyvinylidene chloride) are low permeability, barrier properties, and chemical resistance. PVDC in our country has been developed with the introduction of ham sausage processing technology.
In 2002, the domestic production of PVDC was about 20000 tons, and it has been widely used for food, cigarette, beverage preservation and flavor isolation, as well as moisture-proof packaging in the chemical, pharmaceutical, electronic, and military industries.
Single layer PVDC film is produced by bi-directional stretch blow molding, which has shrinkage, barrier, and water resistance properties. It does not decompose under microwave heating conditions and is widely used as household cling film; Multi layer extrusion of PVDC and synthetic resins such as polyethylene (PE), polypropylene (PP), and polystyrene (HIPS) is used for packaging vacuum dairy products, jams, and other products. Its tensile properties are good and suitable for larger volume packaging; The composite sheet of PVDC, PE, and polyvinyl chloride (PVC) is suitable for packaging drugs that are easily hygroscopic and volatile. At present, many domestic research institutions and manufacturers are focusing on the research of PVDC and other resin composite laminated film technology, as well as the high-temperature resistance technology of composite films.
PVDC is used in various substrates such as PE, PP, PVC, polyamide (PA), polyethylene terephthalate (PET), etc. Taking biaxially oriented polypropylene film as an example, after coating, the oxygen permeability decreases by 1000 times and the water permeability decreases by 3 times; Coating can be single-layer or multi-layer, and generally a single-layer coating of 2.5 μ m can have good barrier effect.