There are many varieties of plastic films, which can be applied in many fields such as agriculture, daily necessities, medicines, construction and water treatment, solar power generation, battery separators, bulletproof glass, etc. according to their different characteristics.
* HDPE Film
HDPE membrane is called geomembrane or impermeable membrane. Its melting point is about 110℃-130℃, and the relative density is 0.918-0.965kg/cm3. It is a highly crystalline, non-polar thermoplastic resin. The original HDPE has a milky white appearance and a certain degree of translucency in the thin section. It has good high and low temperature resistance and impact resistance, even at -40F low temperature. Its chemical stability, rigidity, toughness, mechanical strength, and tear resistance are all excellent. With the increase in density, the mechanical properties, barrier properties, tensile strength and heat resistance will increase accordingly. It can resist acids, alkalis, Corrosion by organic solvents.
Identification method: mostly opaque, feel like wax, plastic bag rustling when rubbing or rubbing.
* LDPE Film
LDPE film has low density, softness, low temperature resistance, impact resistance and good chemical stability. In general, it is resistant to acid (except strong oxidizing acid), alkali, salt corrosion, and has good electrical insulation. LDPE is mostly used in plastic bags, and the marked material symbol is No. 4, and its products are mostly used in civil engineering and agricultural fields, such as geomembrane, agricultural film (shed film, mulching film, bitter cover film, green storage film, etc.). The recycled materials and leftover materials can be made into trash cans, tool boxes, bicycle mats, trash carts and other flexible plastic re-products.
Identification method: Plastic bags made of LDPE are softer and less rustling when rubbed. The outer packaging plastic film is soft and easy to tear is LDPE, and the brittle and harder is PVC or PP film.
* PP Film
Ordinary PP film is blow molded, with simple process and low cost, but its optical performance is slightly lower than CPP and BOPP. The biggest feature of PP is high temperature resistance (about -20℃~120℃), and its melting point is as high as 167℃. It is suitable for filling soy milk, rice milk and other products that require steam sterilization. Its hardness is higher than that of PE, and it is mostly used to make container caps. The marked material symbol is No. 5.
Identification method: Generally speaking, PP has a higher hardness and a more shiny surface, and does not produce pungent odor when burned, while PE has a heavier candle smell.
* PEVA Film
PVA Polyvinyl alcohol (PVA) high-barrier composite film is a film with extremely high barrier properties formed by coating a modified polyvinyl alcohol water-soluble liquid on the substrate with polyethylene plastic as the base material. Because the polyvinyl alcohol high-barrier composite film has good barrier properties 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.
* CPP Film
Cast polypropylene film (CPP) is a non-stretched, non-oriented flat extrusion film produced by melt casting quenching. It is characterized by fast production speed, high output, film transparency, gloss, barrier properties, flexibility, and thickness uniformity. It can withstand high temperature cooking (the cooking temperature is above 120 ℃) and low temperature heat sealing (the heat sealing temperature is less than 125℃), excellent balance of various properties. Follow-up work such as printing and compounding is convenient. It is widely used in the packaging of textiles, flowers, food, and daily necessities. As the inner substrate of compound packaging, it can extend the shelf life of food and increase the aesthetics.
*BOPP Film
Biaxially oriented polypropylene film (BOPP) is a transparent flexible packaging material developed in the 1960s. It uses a special production line to mix polypropylene raw materials and functional additives, melt and knead them into sheets, and then stretch them Stretched into a film. This film not only has the original advantages of low density, corrosion resistance, and good heat resistance of PP resin, but also has good optical properties, high mechanical strength, and rich source of raw materials. It has excellent printing performance and can be combined with paper, PET and Composite with other substrates, with high definition and gloss, excellent ink absorption and coating adhesion, high tensile strength, excellent grease barrier properties, low static characteristics, etc. It is widely used in the field of printing and compounding, and at the same time as a packaging material in tobacco and other aspects.
* PET Film
PPolyester film (PET) is a thermoplastic engineering plastic. It is a film material made of thick sheets by extrusion and then biaxially stretched. Polyester film is characterized by excellent mechanical properties, high rigidity, hardness and toughness, puncture resistance, abrasion resistance, high and low temperature resistance, chemical resistance, oil resistance, air tightness and good fragrance retention. It is a commonly used barrier property One of the composite film substrates, but the corona resistance is poor and the price is higher. The thickness of the film is generally 0.12mm. It is commonly used as the outer layer material of food packaging and has good printability. Mark the material symbol as No. 1 in the plastic products. The recycled materials can be re-made: monofilament → wig, zipper serration; sheet → packing box (egg box, stationery L clip); polyester cotton → filled cotton, non-woven fabric, polyester fabric.
* PA Film
Nylon plastic film (polyamide PA) is currently industrialized in many varieties, 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 with good transparency and good gloss. Tensile strength, tensile strength, high and low temperature resistance, oil resistance, organic solvent resistance, abrasion resistance and puncture resistance are all good, and the film is relatively soft, has excellent oxygen barrier properties, but has better barrier properties to water vapor Poor, high moisture absorption and moisture permeability, poor heat sealability. Suitable for packaging hard items, such as greasy foods, meat products, fried foods, vacuum packaged foods, steamed foods, etc.
* PVC Film
The advantages of PVC film and PET are similar. They are transparent, air-tight, and resistant to acids and alkalis. In the early days, many mineral waters were packaged in PVC bottles. However, PVC may release carcinogens due to incomplete polymerization of some monomers during the manufacturing process. Therefore, it is not suitable for filling food-grade substances. Now, most of the PVC bottles have been changed to PET bottles, and the material symbol is No. 3. Recycled materials can be made into: water pipe elbows, artificial leather, wire coverings, fireproof building materials, etc.
* PS Film
PS film has low water absorption, but its size stability is good, and it can be processed by injection molding, compression molding, extrusion, and thermoforming. Generally, it is divided into two types: foamed and unfoamed according to whether it has gone through the foaming process. Unfoamed PS is mainly used in building materials, toys, stationery, etc. It can also be commonly used to make container-filled fermented dairy products (such as dairy products or lactic acid products such as Yakult, Jianjian, Duoduo, etc.). In recent years, it has also been widely used to make disposable products. Tableware, marked with material symbol No. 6. Recycled materials can be remade: it can be used to reproduce hard, fragile, non-flexible plastics such as camera housings and clothes hangers.
* Aluminized film
Aluminized film combines the characteristics of plastic film and metal. The function of aluminum plating on the surface of the film is to shield light and prevent ultraviolet radiation, which not only extends the shelf life of the contents, but also improves the brightness of the film. To a certain extent, it replaces the aluminum foil. It also has low price, beautiful appearance and better barrier properties. Therefore, the application of aluminized film in composite packaging is very wide, mainly used in the packaging of dry and puffed food such as biscuits, and the outer packaging of some medicines and cosmetics.
