Nanotechnology Revamps the Packaging World (4)

Two major application technologies of nano packaging materials

Nano coating technology

High barrier property is one of the basic functional elements of plastic packaging. PET is the preferred material for beverage packaging. It has many advantages such as good transparency, stable chemical properties, relatively good barrier properties, light weight, low cost, and recyclability. Therefore, PET is widely used. However, as a beer bottle, the gas barrier property of PET is still not high enough. Therefore, improving the gas barrier properties of polyester bottles is a primary solution to the problem of plasticization of beer packaging. Among the numerous process technologies, surface coating technology is the earliest, most widely used and most invested new process technology. Today, it has become the main means to improve the gas barrier properties of polyester bottles. In the surface coating technology, the nano-surface coating method is one of the effective methods.

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-type treatment process. It has the advantages of easy operation, cleanness, high efficiency, safety, and no pollution, and can meet environmental protection requirements. The thickness of the plasma surface treatment coating is nano-scale, and the physical properties of the material interface are significantly improved while ensuring that the material substrate is not adversely affected.

Amorphous nano-carbon coating technology (ACTIS) developed by France's Sidel company is to make plasma acetylene agglomerate on the inner wall of PET bottles to form a highly hydrogenated amorphous carbon nano solid film with a thickness of 20~150 nm. The PET bottles treated with the ACTIS process have 30 times more effective oxygen barrier than ordinary PET bottles, 7 times more resistance to CO2, and 6 times more resistance to acetaldehyde. The diamond-based nanocarbon coating process (DLC) uses high-frequency vacuum discharge to form a fine coating of 20 to 40 nm in thickness on the inner surface of the PET bottle, similar to the diamond carbon structure. The PET bottle is more than 20 times more resistant to oxygen than normal PET bottles, 7 times more resistant to CO2, 8 times more resistant to water vapor, and also significantly improved in UV resistance.

The silicon oxide nano-treated PET bottle technology adopts SiO2 for vacuum physical vapor deposition under high vacuum plasma conditions, and the treatment layer is outside the PET bottle. The processing cost of this method is more economical than using PET bottles or multilayer bottles.

DuPont Polyester (DU PONT) has developed a new two-stage overcoating technology to increase the barrier properties of PET bottles to O2 and CO2 by 30 times. The primer can be separated by water and the material recovery is very high. Convenient, is an excellent green packaging.

Nano Additive Technology

With the rapid development of packaging, the increase in demand for special functions of packaging, such as explosion-proof, anti-electromagnetic, camouflage, high barrier, and UV-resistant packaging, has prompted the development of nano-packaging technology. The nano-composite nano-packaging material is a high-tech material. If 10% nano TLMC (thermotropic liquid crystal polymer) is added to the high molecular polymer, the tensile strength of the material will be increased to 450 MPa, thereby greatly expanding its use and saving scarce resources.

In May 2004, the British company Foraday announced that in order to cooperate with the environment, they will use nanotechnology in the ultrathin layers of polymer molecules. In the future, this product will provide new functions for packaging materials. This study is closely related to physics and chemistry. Chemists have found a way to make polymer layers one molecule thick, while physicists study the properties of each layer at the level of a single molecule. These results will enable individual molecules to react according to the environment, protecting the product based on changes in temperature and humidity.

Nano-preservation packaging materials can improve the fresh-keeping effect of fresh fruits and vegetables and extend the shelf life. Adding nano-silver powder to the fresh-keeping packaging material can accelerate the release of ethylene from the oxidized fruits and vegetables and reduce the ethylene content in the package, thereby achieving a good preservation effect. The application of nanotechnology in UV protection materials, such as the addition of nano-UV protection powder in UV protection packaging materials, makes the manufactured UV protection packaging bags achieve better UV protection.

Metal nanoparticles have the special function of eliminating static electricity. As long as a small amount of metal nanoparticles is added during the production of packaging materials, static electricity can be eliminated, so that the surface of the package will no longer absorb dust and reduce friction-induced scratches, while printing, Due to the absence of electrostatic adsorption on the surface, it helps to increase the printing speed and improve the printing effect.