Analysis of the characteristics and uses of seven plastic film products

1. Biaxially oriented polypropylene film (BOPP)

Biaxially oriented polypropylene film is a transparent flexible packaging material developed in the 20s of the 60th century. It is a special production line to mix polypropylene raw materials and functional additives, melt mix, make sheets, and then stretch to make films.

BOPP film not only has the advantages of low density, good corrosion resistance and good heat resistance of PP resin, but also has good optical properties, high mechanical strength and rich sources of raw materials.

In addition, it can also be applied to the preparation of high value-added functional products such as electrical membranes and microporous membranes, so the development prospects of BOPP films are very broad. By 2004, the production capacity of China's BOPP film production line was 190.176 million tons, and the actual output was about <>.<> million tons.

2. PVA coated with high barrier plastic film

Polyvinyl alcohol high barrier composite film is a film with extremely high barrier formed by coating a modified polyvinyl alcohol water-soluble liquid on the substrate based on polyethylene plastic.

Because polyvinyl alcohol high-barrier composite film has good barrier performance and meets environmental protection requirements, the market prospect of this kind of packaging material is very bright, and there is a broad market space in the food industry.

3. Low density polyethylene film (LDPE)

Low-density polyethylene is a synthetic resin obtained by the radical polymerization of ethylene under high pressure, so it is also known as "high-pressure polyethylene". LPDE is a branched chain molecule with different lengths and short branches on the main chain, and about 1000~15 ethyl, butyl or longer branched chains per 30 carbon atoms on the main chain.

Because the molecular chain contains more long and short branched chains, the product has low density, softness, low temperature resistance, good impact resistance, good chemical stability, acid resistance (except strong oxidizing acid), alkali resistance, salt corrosion resistance, and good electrical insulation performance.

Low-density polyethylene films are also widely used, such as packaging. There are many types of polyethylene packaging films, and their properties are also different, single-layer film performance is single, composite film performance is complementary, and has become the main material for food packaging.

Secondly, polyethylene membranes are also used in the field of civil engineering, such as geomembranes. It is waterproof in civil engineering and has very low permeability. Agricultural film is applied in agriculture, which can be divided into shed film, mulch film, bitter cover film, green storage film, etc.

4. Mylar film (PET)

Mylar film (PET) is a thermoplastic engineering plastic. A film material made of thick sheets by extrusion and then biaxially stretched.

Mylar film is characterized by excellent mechanical properties, high rigidity, hardness and toughness, puncture resistance, friction resistance, high and low temperature resistance, chemical resistance, oil resistance, air tightness and good fragrance retention, is one of the commonly used permeabilizing composite film substrates, but the corona resistance is not good.

The price of polyester film is higher, the thickness is generally 0.12mm, commonly used as the outer material of food packaging packaging, and the printability is better. Due to the complexity and difficulty of judgment of polyester film, it brings certain difficulties to the supervision of customs.

5. Nylon plastic film

The chemical name of nylon is polyamide (PA), and there are many varieties of nylon currently industrially produced, among which the main varieties used to produce films are nylon 6, nylon 12, nylon 66 and so on.

Nylon film is a very tough film, good transparency, and has good luster, tensile strength, high tensile strength, but also has good heat resistance, cold resistance, oil resistance and organic solvent resistance, wear resistance, puncture resistance is excellent, and relatively soft, excellent oxygen resistance, but poor barrier to water vapor, moisture absorption, moisture permeability, poor heat sealability, suitable for packaging hard items, such as greasy food, meat products, fried food, vacuum packaged food, steamed food, etc.

6. Cast polypropylene film (CPP)

Cast film is a non-stretching, non-directional flat extruded film produced by melt casting quenching. It is characterized by fast production speed, high output, film transparency, gloss, thickness uniformity, and excellent balance of properties.

Because it is a flat extruded film, the follow-up work such as printing, lamination, etc. is extremely convenient, and it is widely used in the packaging of textiles, flowers, food, and daily necessities.

7. Aluminized plastic film

Aluminized film has both the characteristics of plastic film and the characteristics of metal. The function of aluminum plating on the surface of the film is shading, anti-ultraviolet radiation, which not only extends the shelf life of the content, but also improves the brightness of the film, replacing aluminum foil to a certain extent, and also has low price, beautiful and good barrier performance.

Therefore, the application of aluminized film in composite packaging is very extensive, mainly used in dry and puffed food packaging such as biscuits, as well as some pharmaceutical and cosmetic packaging.