Processing and application of shrink PET filmPET thermal shrinkage film is a new type of thermal shrinkage packaging material. Polyester (PET) has become an ideal substitute for PVC (PVC) thermal shrinkage film in developed countries due to its characteristics such as easy recovery, non-toxic, tasteless, good mechanical properties, especially in line with environmental protection.In addition to shrinkable label, thermoplastic film has also been used in the outer packing of daily goods in recent years. Because it can not only make the packaging goods to avoid impact, rain, moistureproof, rustproof, but also make the products to print elegant packaging to win users, at the same time it can well show the good image of manufacturers. At present, more and more packaging manufacturers use printing shrinkage film instead of the traditional transparent film. Because the printing shrinkage film can improve the appearance of the product, is conducive to the advertising of the product, can make the brand in the hearts of consumers have a deep impression.Thermally shrinkable plastic film is required to be stable at room temperature, shrink when heated (above vitrification temperature), and it is ideal to have more than 50% thermal shrinkage in one direction. Thermal shrinkage plastic film packaging features are: fit transparent, reflect the image of the commodity; Tight packing, good dispersion resistance; Resistant to rain, moisture and mildew; No recovery, has a certain anti-counterfeiting function. Thermo-shrink plastic film is often used in convenient food, beverage, electronic appliances, metal products, etc., especially shrinkable label is its main application field.Copolymerization modification of thermotropic polyester (PET) filmsPolyester (PET) film is a kind of crystallized material. Ordinary PET film can only obtain thermal shrinkage rate of less than 30% after special treatment. In order to obtain polyester film with high thermal shrinkage, it must be modified. In other words, in order to prepare polyester films with high thermal shrinkage, it is necessary to copolymerize common polyester, i.e. polyethylene terephthalate. The maximum thermal shrinkage of copolymerized PET films can be as high as 70%.Ordinary polyester is generally made from terephthalic acid (PTA) and ethylene glycol (EG) through esterification and condensation reaction, which belongs to crystalline polymer (strictly speaking, it is a polymer co-existing in crystalline and amorphous regions). The so-called copolymerization modification is to introduce the third or even the fourth component in addition to the two main components of terephthalic acid (PTA) and ethylene glycol (EG) to participate in the copolymerization, with the purpose to make them form asymmetric molecular structure and form amorphous PET copolymer.The third monomer that’s introduced can also be a dihydric alcohol. The most common diol is 1.4 cyclohexane dimethyl alcohol (CHDM). In the process of polyester copolymerization, the addition of CHDM has a great influence on the tg, TM and crystallization rate of polyester. With the increase of CHDM content, the melting point of pet PETG decreases, the glass transition temperature increases, and the copolymer becomes amorphous structure. However, 1.4 The addition amount of cyclohexanedimethanol (CHDM) should be controlled within an appropriate range, and generally 30~40% of CHDM is recommended. This kind of PETG modified with diol can not only be used for the preparation of high-shrinkage films, but also for the production of heat sealing films and high-transparency films, etc., with a wide range of applications.Of the third monomer introduced above, the most commonly used binary carboxylic acid is m-phthalic acid (IPA). The addition of IPA can change the symmetric tight structure of polyester, destroy the regularity of macromolecular chain, reduce the interaction between macromolecules, and make the polyester molecular structure more pliable. At the same time, due to the introduction of IPA, polyester is difficult to nucleate and crystallize, and with the increase of the amount of IPA introduced, APET copolymers transition from partial crystallization to non-crystalline polymer. Due to the decline of the crystallization ability of this modified polyester APET, the amorphous region becomes larger, so it can be used to manufacture high-shrinkage films. It is recommended to add about 20% IPA.The third or even fourth monomer introduced may be a diacid or a diol. Among them, the binary carboxylic acids are m-phthalic acid, malonic acid, succinic acid, adipate, sebacic acid, etc. Diols include neopentyl glycol, propylene glycol, diethylene glycol, 1.4 cyclohexane dimethyl alcohol, etc. After being autoclaved, APET copolymer is produced by autochthonous acid (autochthonous acid). The PET copolymer obtained by copolymerization with Glycolic is called PETG.Thermal shrinkage plastic film is generally made of amorphous plastic processing, such as polystyrene, polyvinyl chloride, PVDC and so on. Polystyrene (PS) shrinkage film has low strength and is not impact resistant, so it is rarely used. And polyvinyl chloride (PVC) is not conducive to recycling treatment, do not meet the environmental requirements. Abroad, especially in Europe, polyvinyl chloride (PVC) plastic film has been banned in the packaging field, especially in food packaging.

COLD PEEL MATTE FINISH HEAT TRANSFER PET FILM FOR SCREEN PRINTING