PETG: High Technology Monopoly and Promising Application Prospects
Click:0    DateTime:Nov.24,2020

By Guo Hao, China National Chemical Information Center


Polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG), as a transparent non-crystalline copolyester, is more environmentally friendly compared with other polyester materials, has been certified by FDA as food and medicine, and has excellent light transmittance. It can replace traditional materials in many applications.

Domestic consumption mainly depends on imports

   Copolyester PETG was successfully developed in the United States in the 1980s. It is the product of the polycondensation of terephthalic acid (PTA), ethylene glycol (EG) and 1,4-cyclohexanedimethanol (CHDM) by transesterification. The mainstream synthesis route of PETG is divided into two steps: firstly, PTA and alcohols (ethylene glycol and CHDM) are esterified to form the polycondensation monomer bishydroxyethyl terephthalate (BHET) and bishydroxymethylcyclohexyl terephthalate methyl ester (BHCT); secondly, BHET and BHCT are polycondensed to get PETG.

   There are two major PETG manufacturers in the world, namely Eastman of the United States and SK of South Korea, with a global capacity of 300 kt/a. Due to the high technical requirement and the relatively limited market demand, few companies have the intention to start PETG production. At present, China’s Liaoyang Petrochemical has a PETG line with the capacity at 10 kt/a, and Zhuhai China Resources has a plan to build a PETG unit, which is expected to be put into production in the next 2 to 3 years.
   In 2019, the global consumption of PETG was approximately 270 kt, of which 140 kt were consumed in the Asia-Pacific region, accounting for 52% of the total. China consumed about 90 kt, with an import dependence of 90%, and the major consumers are in the southeast coastal areas.

Environmental protection and high light transmittance

   PETG has excellent optical properties with high gloss surface and low turbidity, and its light transmittance is as high as 90%, which is similar to PMMA and superior to PC. As an environmentally friendly material, PETG can be in contact with cosmetics and food. Since bisphenol A is not contained in its raw materials, it has become the main substitute for non-environmentally friendly and transparent materials such as PVC.
   The packaging materials for cosmetics are mostly high translucent materials such as PS and PMMA. With more and more attention paid to environmental protection and safety, the cosmetics markets, especially South Korea began to promote the new environmentally friendly material PETG, and such trend has gradually spread to China and the global market.
   In addition to environmental protection and high light transmittance, PETG also has good chemical resistance. Its oil resistance and weather resistance (yellowing) performance are better than PET, and it can hold common weak acids and weak bases, coffee, chocolate, daily chemical products, detergents and perfumes, etc.

Applications in light industry

   PETG has excellent molding and cold bending performance, without whitening and cracks, and is easy to print and decorate. Therefore, PETG is widely used as high-end card materials. As one of the most used credit cards in the world, visa has identified PETG as its card material. In addition, PETG, designated by the Ministry of Public Security of China, is the base material of the second-generation ID card. Meanwhile, it is also widely used in subway cards and social security cards. See Table 1 for the comparison of various types of materials as card base materials.

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Because PETG has a good final shrinkage rate, it is widely used in the production of high-performance shrink films. PETG film can be used for the packaging of complex-shaped containers. It has the advantages of high plasticity, high transparency, high gloss, low haze, etc., is easy to print, has low natural shrinkage during storage, and is not easy to fall off. It is mainly used in shrink packaging of beverage bottles, food and cosmetics, and shrink labels of electronic products. Compared with PVC shrink film, the biggest advantage of PETG shrink film is environmental protection and safety, as shown in Table 2.

QQ截图20201124102838

   In terms of high light transmission bottles, PETG has the same transparency and similar density to the glass and has good gloss too. PETG also has good toughness and high impact strength, which can ensure that the product is not easy to be broken or scratched. In addition, the feature of easy processing makes PETG suitable for injection, blow molding, extrusion and other processing methods. It can also produce unique shapes, appearances, and special effects, such as bright colors, frosted, marble texture, metallic luster, etc.
   The applications of PETG are basically concentrated in the field of light industry. In addition to the aforementioned card materials, packaging films, and high-transparent bottles, it is also widely used in decoration and medical products. In the future, PETG will be more involved in daily life. It is estimated that China’s PETG demand will continue to grow by 2025. At the same time, with the capacity expansion and price reduction, PETG applications in the end market will also be expanded.