A wide range of plastic film, according to their different characteristics used in agriculture, daily necessities, pharmaceuticals, construction and water treatment, solar power, battery separator, bullet-proof glass and many other areas.
Film forming
Plastic film molding methods are many, including casting, extrusion, blow molding of these three processes are more common:
Casting method : A non-oriented, non-oriented, cast-in film is produced by the melt-cooling process without the apparent orientation of the film.
Extrusion method : Common unidirectional stretching and biaxial stretching method. The basic principle of biaxial stretching: polymer raw materials are heated through the extruder melt extruded into thick pieces, and then above the glass transition temperature below the melting point of the appropriate In the temperature range, a certain multiple of stretching is performed in the longitudinal direction and the transverse direction by the stretcher to align the molecular chains in an orderly arrangement in a plane parallel to the film and then heat-set in a stretched state so that the orientation Macromolecular structure fixed, and finally cooled and subsequent processing of film.
Blow molding method : Usually extrusion blow molding, plastic material extrusion, forming a tube inflatable molding, and then cooling, traction, coiling. Blown film is oriented. Blow film forming process is simple, is the most commonly used Film-forming process. A variety of film characteristics
HDPE
HDPE film is called geomembrane or impermeable membrane.The melting point is about 110 ℃ -130 ℃, the relative density of 0.918-0.965kg / cm3 is a high crystallinity, non-polar thermoplastic resin, the appearance of the original HDPE Milky white and slightly translucent on a thin section with good resistance to high and low temperature and impact, even at low temperatures of -40 F. Its chemical stability, rigidity, toughness, mechanical strength, tear resistance Excellent mechanical properties, barrier properties, tensile strength and heat resistance will be increased accordingly, acid, alkali, organic solvents etc .. Identification method: mostly opaque, feel like the wax , Plastic bags rubbing or friction rustle.
LDPE
LDPE film density is low, soft, low temperature resistance, good chemical resistance of impact resistance, under normal circumstances, acid (except the strong oxidizing acid), alkali, salt corrosion, with good electrical insulation. LDPE most used In plastic bags, the symbol of the material is - 4, its products are mostly used in civil engineering and agricultural fields, such as geomembrane, agricultural film (film, film, bitter cover film, Scrap, etc. can be re-made trash, toolbox, bicycle mats, garbage trucks and other flexible plastic re-products. Identification method: LDPE made of plastic bags softer, less rustle when rubbing, packaging Plastic film is soft and easy to tear LDPE, more brittle and hard PVC or PP film.
PP
Ordinary PP film using blow molding, simple process, low cost, but slightly lower than the optical performance of CPP and BOPP. PP most prominent feature is high temperature (about -20 ℃ ~ 120 ℃), and melting point up to 167 ℃, suitable for filling milk , Rice milk and other products that require steam sterilization.The hardness is higher than PE to produce the majority of container caps, marking material symbol 5. Identification method: In general, PP hardness is higher, and the surface is more shiny, burning Does not produce irritating smell, while PE has a heavier candle flavor.
PVA
Polyvinyl alcohol (PVA) high barrier composite membrane is based on polyethylene plastic substrate, the modified polyvinyl alcohol water-soluble liquid coating on the substrate formed with a very high barrier film.As a result of polyvinyl alcohol High barrier composite membrane has good barrier properties, and meet the environmental requirements, therefore, the kind of packaging materials market prospects are bright, in the food industry has a vast market space.
CPP
Cast polypropylene film (CPP) is an unstretched, non-oriented, cast film produced by melt casting and quenching, featuring fast production speeds, high yields, film clarity, gloss, barrier Good flexibility, uniform thickness, high temperature cooking (cooking temperature above 120 ℃) and low temperature heat sealing (heat sealing temperature less than 125 ℃), the performance balance is excellent. Follow-up work such as printing, complex convenient, Widely used in the packaging of textiles, flowers, foodstuffs, and daily necessities, the inner layer of composite packaging substrate can extend the shelf life of food and increase the appearance.
BOPP
BOPP is a kind of transparent and flexible packaging material developed in the 1960s. It uses a special production line to mix polypropylene raw materials and functional additives, melt-knead them into sheets, and then pull Stretch into a film. This film not only has the original low density PP resin, corrosion resistance, heat resistance and good, and good optical properties of the film, high mechanical strength, rich source of raw materials, has excellent printing properties, can be Complex with paper, PET and other substrates with high definition and gloss, excellent ink absorption and coating adhesion, high tensile strength, excellent grease barrier properties, low electrostatic properties, etc. In the field of printing composites Wider, while in the tobacco and other aspects as a packaging material.
PET
Polyester film (PET) is a kind of thermoplastic engineering plastic.It is made by the extrusion method, the thick film, then the film material made by biaxial stretching.The polyester film is characterized by excellent mechanical properties, rigidity, high hardness and toughness, Puncture resistance, abrasion resistance, high temperature resistance, chemical resistance, oil resistance, air tightness and good aroma, is commonly used barrier composite film substrate, but less corona resistance, the price is more High.Film thickness is generally 0.12mm, commonly used as the outer packaging of food packaging materials, printing is better. Marked in the plastic material symbol is 1. The renewable material can be made into: monofilament → wig, zipper Serrated; sheet → box (egg box, stationery L clip); polyester cotton → filled cotton, non-woven, polyester cloth.
PA
Nylon plastic film (polyamide PA) Currently a lot of varieties of industrial production, which used to produce the main film varieties are nylon 6, nylon 12, nylon 66. Nylon film is a very tough film, good transparency, and has Good luster Tensile strength, tensile strength, high and low temperature resistance, oil resistance, organic solvent resistance, abrasion resistance and puncture resistance are good, and the film is relatively soft, excellent oxygen barrier, but the water vapor Poor barrier properties, moisture absorption, moisture permeability, heat sealing is poor.Applicable to the packaging of rigid items, such as greasy food, meat products, fried foods, vacuum-packed food, cooking food.
PVC
Similar advantages of PVC film and PET, belong to the same transparent, airtight, acid-base properties, many early spring mineral water packaging is the use of PVC bottles.But PVC due to the manufacturing process may be due to incomplete polymerization of some monomers to release carcinogens, therefore Not suitable for filling food-grade material, now have switched to PET bottles, marked material symbol 3. Recycled material can be made into: pipe elbow, artificial leather, wire coating, fire prevention building materials.
PS
PS film has low water absorption, but its dimensional stability is better, it can be shot, compression molding, extrusion, thermoforming processing.Generally according to its whether through the foaming process is divided into two types of foam and non-foaming. Bubble PS is mainly used in building materials, toys, stationery, etc., can also be made into container filled fermented milk products (such as Yakult, Kincaid, many and other dairy products or lactic acid products), etc. In recent years, it is also widely used in making disposable dishware, Marking material symbol 6. Recycled material can be made: you can shoot the camera shell, racks and other hard brittle, non-flexible plastic re-products.
Aluminum
Aluminum coated with both plastic film and metal characteristics of the aluminum film surface is the role of shading, UV radiation, both to extend the shelf life of the content, but also improve the brightness of the film, to a certain extent, instead of aluminum foil also has Cheap, beautiful and better barrier performance.Therefore, aluminized film in the composite packaging is widely used, mainly used in biscuits and other dry, puffed food packaging, as well as some pharmaceutical, cosmetic packaging.