Development status of "high-performance polyester drinking bottle" in the world (2)

Plasma coating modification technology

Polyester (PLYESTER) - is the 20th century packaging industry's greatest invention. For polyesters, modification with surface nanocoating is the most important, one of the most effective methods. It uses a variety of high-barrier coatings and various coating technologies to form a very thin barrier coating on the inside and outside surfaces of PET bottles to block the ingress and egress of gases and improve the air permeability, so as to achieve long shelf life for food preservation. Applications have become more widespread.

Among the various surface technology coating methods, plasma nano-coating technology has the greatest market potential, and it is also a hot spot for modern development. The plasma nano-surface treatment research began in the late 20th century. It is a vacuum dry treatment process, which has the advantages of simple operation, cleanness, high efficiency, safety and no pollution, and can meet the requirements of environmental protection. The plasma surface treatment coating has a nanometer-scale thickness, and the physical properties of the material interface are significantly improved while ensuring that the material substrate is not adversely affected.

Silicon oxide coating modification technology

According to the latest information, COCA-COLA Co., Ltd. of the United States cooperated with Essen University, Germany, Krones GmbH and Leybold Systems of Germany to develop the silicon oxide nano-treated PET bottle technology to improve the barrier properties. The technique is to use SiOx for vacuum physical vapor deposition under high vacuum plasma conditions, with the treatment layer outside the PET bottle. It has been reported that PET bottles treated with this process can increase barrier properties by a factor of 4 and extend the shelf life of at least 6 months without affecting the odor of beer. According to Germany: Krones Company stated that the treatment cost of this method is more economical than using: PEN bottle or multilayer bottle. In cooperation with Leybold, the company has installed a production line at a filling factory in Germany for a Coca-Cola company.

In addition, according to foreign reports, Switzerland's Tetra Pak Packaging has developed a technique for plasma coating of nano-SiOx coatings on the inner wall of PET bottles. This process can form a glass-like barrier coating with a thickness of 50 to 100 nm on the inner wall of PET bottles. Floor. Filling beer or juice with this bottle, the shelf life can be extended to 12 months. The system can handle 18,000 PE3 and 2L bottles per hour and has been applied by Spendrups in Sweden. The market prospect is very good.

Diamond-shaped carbon coating modification technology

According to a recent report in the Journal, Japan's Nissei ASB Co., Ltd., in partnership with Japan Kirin Brewery, Mitsubishi Corporation and YOUTEC, have jointly collaborated to develop a diamond-based nanocarbon coating process (DLC). The DLC process uses high-frequency vacuum discharge, so that ionized carbon and hydrogen form a fine coating with a thickness of 20 to 40 nm and a diamond-like carbon structure on the inner surface of the PET bottle. The PEAT bottle is more oxygen barrier than ordinary PET. The bottle is raised by more than 20 times, the permeability to CO2 is increased by 7 times, the barrier to water vapor is increased by 8 times, and the UV resistance is also greatly improved. The nano-coating is not only highly transparent, the coating is not easy to crack, but also has good acid and alkali resistance. These companies are cooperating to develop industrial production equipment and plan to first promote it to the Southeast Asian market.

Other coating modification technologies

According to incomplete reports, Italy's Sipa Corporation has developed an epoxy polyurethane outer coating PET bottle. This process uses the epoxy polyurethane barrier coating of PPG Company of the United States to form a bright abrasion resistance and scratch resistance barrier coating. Swiss instant surface technology company developed a plasma coating technology at atmospheric pressure, so that the barrier layer deposited on the inner wall of the PET bottle. It is said that this technology does not require expensive equipment and simplifies the coating process, and the oxygen barrier of the coated PET bottle is 10 times higher than that of the conventional bottle. In addition, Switzerland's Tetrs Pak also introduced a new barrier coating technology, using a PET bottle, to achieve the desired barrier effect by adjusting the thickness of the barrier layer. The barrier layer is a Dow Chemical Company's thermoplastic epoxy resin, both high transparency and excellent gas barrier properties.

Recently, DuPont Polyester (DU PONT) Co., Ltd. has developed a new two-stage overcoating technology to increase the barrier properties of PET bottles to 02 and CO2 by 30 times, and the primer can be separated by water. Recycling is very convenient, it is a beautiful green packaging. Another external coating technology developed by DuPont, called “transparent aluminum”, can increase the barrier properties of PET bottles by 30 to 40 times. This technology is close to commercialization.

Even so, the improved barrier properties of the surface coating technology may be affected by the surface area of ​​the bottle. In addition, the inner coating has the problem of food safety and must be certified by a security agency. In addition, the toughness of some of the coatings is poor, and the SiOx coating is relatively brittle and easy to drop. However, other methods also have more or less problems, which must be further improved.

All in all, in the future we have a long way to go in the world of packaging. There is a lot of work to be done to develop a new process for coating nano-surfaces and improve the performance of drinking PET bottles.