Properties, use and type of polyester film PET

Polyester film is made of polyethylene terephthalate (English name: polyethylene terephthalate, referred to as PET) as raw material, the use of extrusion made of thick film, and then by the two-way stretch made of thin film material. It is a colorless, transparent, shiny plastic film (can add the additive particles to make it color), excellent mechanical properties, rigidity, hardness and toughness, puncture resistance, abrasion resistance, high temperature and low temperature, chemical resistance , Oil resistance, printability, air tightness and good fragrance, is commonly used barrier composite film substrate. Polyester film (also known as film polyester film photosensitive paper polyester film benzene tin film cellophane from the film) is a polymer plastic film, because of its comprehensive performance and more and more by the vast number of consumers of all ages. Commonly used to do fiber, packaging film, engineering plastics, polyester bottles, cooking packaging, such as the outer layer of materials.

First, according to the polyester film materials and process classification:

1, biaxially stretched polyester film (referred to as BOPET), is the use of light (also known as a large amount of light, that is, in the raw material polyester chips (titanium dioxide content of 0.1%) by drying, melting, extrusion, Vertical and horizontal stretch of high-grade film, widely used). BOPET film with high strength, good rigidity, transparency, high gloss characteristics; odorless, odorless, colorless, non-toxic, outstanding strength and toughness; its tensile strength is PC polycarbonate film, PA nylon film 3 times, Impact strength is 3-5 times the BOPP film, with excellent wear resistance, folding resistance, resistance to pinhole and tear resistance; heat shrinkage is very small, at 120 ℃, 15 minutes after only shrink 1.25%; has good antistatic properties, easy to vacuum aluminum, can be coated PVDC, thereby enhancing its heat sealing, blocking and printing adhesion; BOPET also has good heat resistance, excellent resistance to cooking , Low temperature resistance, good oil resistance and chemical resistance. BOPET film in addition to nitrobenzene, chloroform, benzyl alcohol, the majority of chemicals can not make it dissolved. However, BOPET will be subject to strong alkali erosion, in actual use should pay attention. BOPET film water absorption is low, good water resistance, suitable for packaging high water content of food.

2, one-way stretch polyester film (referred to as CPET), is the use of semi-extinction material (in the raw material polyester chips added titanium dioxide) after drying, melting, extrusion, casting and longitudinal stretching of the film, The lowest grade and lowest price in the film is mainly used for pharmaceutical tablet packaging. Due to the use of less manufacturers less large-scale production, accounting for about 5% of the field of polyester film, domestic enterprises are less imported. Standard thickness of 150μm and other specifications.

Second, according to the use of polyester film classification:

The characteristics of the polyester film determine its different uses. Different uses of polyester film on raw materials and additives requirements and processing technology have different requirements, the thickness and technical indicators are not the same. In addition, only BOPET has a variety of uses, so according to the use of the classification of the film are BOPET. Specific can be divided into the following:

1, PET electrical insulation film

Because of its good electrical, mechanical, thermal and chemical inertia, good insulation properties, high resistance to wear high, dedicated to electronic, electrical insulation materials. Common standard thicknesses are: 25 μm, 36 μm, 40 μm, 48 μm, 50 μm, 70 μm, 75 μm, 80 μm, 100 μm and 125 μm. Including wire and cable insulation film (thickness of 25-75μm) and touch switch insulation film (50-75μm).

2, PET film

It has the characteristics of high tensile strength, high dielectric constant, low loss factor, good uniformity of thickness, good electrical performance and large electric resistance. It has been widely used in capacitor medium and insulation compartment. The standard standard thickness is 3.5 m, 3.8 m, 4 m, 4.3 m, 4.8 m, 5 m, 6 m, 8 m, 9 m, 9.8 m, 10 m, 12 m.

3, PET card protection film

It has excellent transparency, high stiffness, good heat stability, excellent surface finish performance, uniform vertical and horizontal tensile properties, and has excellent performance such as waterproof, oil and chemical resistance. Dedicated to pictures, documents, documents and office supplies to protect the packaging, so as to protect the film after the hot and smooth, to maintain the original clear and no deformation. The standard standard thickness is 10.75μm, 12μm, 15μm, 25μm, 28μm, 30μm, 36μm, 45μm, 55μm, 65μm, 70μm, etc., which is mainly used as laser anti-counterfeiting base film or high-grade protective film.

4, PET universal film

With excellent strength and dimensional stability, cold resistance and chemical stability, widely used in composite packaging, photographic film, metal vapor deposition, audio and video recording and other substrates. Specifically have the following:

① semi-reinforced membrane. The most important feature is the long tensile strength, in the larger tension is not easy to break, mainly for boxed items such as packaging seals. Common standard thickness of 20μm, 28μm, 30μm, 36μm, 50μm and so on.

② bronzing film. The biggest feature is the tensile strength and transparency is good, thermal performance and stability, with some of the resin binding force is low. Mainly suitable for high temperature processing in the process of small changes in size or as a transfer carrier on the use. Conventional standard thicknesses are 9 μm, 12 μm, 15 μm, 19 μm, 25 μm, 36 μm, and the like.

③ printing composite packaging film. The main features are good transparency, good penetration resistance, excellent chemical resistance, temperature, moisture. It is suitable for the packaging of frozen food and food, medicine, industrial products and cosmetics. Common standard thickness of 12μm, 15μm, 23μm, 36μm and so on.

④ aluminum film. The main features are high strength, good temperature and chemical resistance, good processing and anti-aging properties, the appropriate corona treatment, making the adhesion of aluminum and thin film more firmly. It can be widely used in tea bags, milk powder, candy, biscuits and other food packaging bags, but also as decorative film such as string flower crafts, Christmas trees and other decorations; also applies to the printing compound bag or cardboard bag Such as packaging film. Conventional standard thicknesses are 12 μm, 16 μm, 25 μm, 36 μm, and the like.

⑤ magnetic recording film. With good dimensional stability, uniform thickness, high tensile strength. Suitable for base and special packaging of magnetic recording materials, including audio and video tape base (commonly used standard thickness of 9-12μm) and black film (commonly used standard thickness of 35-36μm).

5, nano-PET film

A. High transparency and gloss: nano-particle size between 1 ~ 100nm, less than the wavelength of visible light, less impact on the transparency of the film.

B. High barrier properties and heat resistance: the use of special properties of nano-materials and unique processing technology, nano-materials were nano-size uniform dispersion of PET matrix in the film production process by stretching the orientation, so that PET film Excellent barrier properties, O, CO2, H2O and other material transmission rate decreased, heat resistance is also greatly improved. Based on its characteristics, thus expanding the application of PET, greatly extending the shelf life of the packaging, can also be used for hot filling or disinfection sterilization industry.

Third, according to the quality of polyester film classification:

According to the quality of polyester film, different manufacturers have different classification names. Our manufacturers are generally divided into excellent products, first-class goods and qualified products, and foreign manufacturers are generally divided into A-class products, B-class products and C-class products. General manufacturers of products sold in the A-class products accounted for 97-98%, B-class products accounted for only 2-3%. C grade products, that is, nonconforming products, not in the field of circulation sales, the main reason is the high price of raw materials, the general manufacturers to return to the furnace as a raw material to use, or as a short fiber sold to textile raw materials for textile mills. Foreign manufacturers sometimes also quarterly or every six months of the stock film when the B-class goods sold, this approach is also some Southeast Asian countries, the practice of manufacturers, the purpose is to reduce inventory.