Sensitive beverage coating scheme

The barrier properties of plastic bottles have always been the biggest challenge for beverage manufacturers, and many barrier materials and technologies have emerged in the market. The most recent method is a plasma coating system in which the material of the barrier layer is uniformly and thinly applied to the inner wall surface of the bottle.

Reactors in the Schott HiCotec Laboratory

Germany's SIG Corpoplast Corp. and Schott HiCotec of Germany jointly developed a new type of plasma coating equipment with unique features. This device was launched in mid-2003 and was named PLASMAX to improve the barrier properties of PET bottles.

Schott HiCotec of Germany developed Plasma Pulse Chemical Vapor Deposition (PICVD) and has been used in glass and plastic coatings for 15 years. The new PLASMAX will be the first device used for the PET bottle coating process. A pulse called "COLD" plasma is deposited on an ultra-thin glass barrier layer SiOx and evenly coated on the inner wall of the bottle, effectively improving the barrier effect. In addition, the build-up is carried out on continuous production high-performance turntables to ensure an efficient and reliable bottle transfer. The flexible design and compact size make SIG Corpoplast's Cobolas equipment suitable for different filling lines.

In terms of process engineering, the requirements for the equipment are high. With its unique PET bottle coating technology, reliable process control and monitoring of a three-stage protection method, high stability handling and safe operation are ensured. The highly flexible system allows for an adjustable blocker for individual application software.

In the current phase, SIG Corpoplast Corp. will establish new industry standards for new plasma coating equipment for use in PET bottles for the treatment of sensitive beverages and beer. It can also be used to produce high quality and small capacity. Carbonated beverage bottle.

In the development of new barrier processes, equipment and product manufacturing have increasingly focused on plasma coatings because it allows the application of 0.01-01 μm ultra-thin barrier layers on top of bottles. However, there are still some deficiencies in use so far, so the beverage industry is still waiting for a major new breakthrough.

Sticking firmly together

The quality of the barrier is very good. Since the special adhesive layer is applied at the beginning of the coating cycle, there is a good bond between the barrier layer and the inner wall of the bottle. Even if the bottle geometry is very complicated, pulsed plasma can effectively and uniformly coat the SiOx barrier layer on the bottle wall. Therefore, this process achieves a very good Barrier Layer Improvement Factor (BIF) compared to uncoated bottles. Due to the firm adhesion, the advantages of the bottle wall can be better reflected when the load is applied to the bottle wall and the expansion (creep) occurs.

BIF O2 (Oxygen) = 10 - 30
BIF CO2 (carbon dioxide) = 4 - 7

The SiOx barrier layer is glassy, ​​colorless and absolutely transparent. The current forecast is that it will be successfully approved by the FDA (United States Food and Drug Administration). SiOx-coated bottles can be recycled through a variety of recognized recycling techniques. Most of the processes do not require additional processes. Recycling can be performed locally during the post-consumer pulverization (PCR) process, or it can be performed collectively in PIR.

Internal coating enhances protection

Schott's PICVD process is generally used for internal and external coatings. However, the application currently plans only internal accumulation. Internal stacking provides a number of major advantages:

* The barrier layer will not be damaged;
* Barrier layer can strengthen the protection of the beverage in the bottle, so that it will not be affected by the gas contained in the bottle such as oxygen and acetaldehyde;
* As the filled beverage does not directly contact the bottle wall base material, it can support PCR applications;
* The machine does not need to be cleaned.

Accumulation process is performed when the bottle mouth is down

In the BLOMAX stretch blow molding process, the plasma build-up process is carried out with the bottle mouth down and the bottom of the bottle upside down (bottle inversion) so as to avoid contamination of the bottles or contamination of the filled products due to loose particles .

According to the design, the first series of equipment yields 10,000 bottles per hour. Therefore, in terms of output, it can be used in conjunction with most aseptic filling machines in direct online operations.

The extremely strict tolerance requirements are complied with in the deviation of process parameters, so that reliable process control and extremely high operational safety are achieved. In this way, a good uniform coating is obtained without any additional process steps after the coating.

Enhancing Purity Through Pulsed Processes

PICVD also offers further advantages in process flow. The pulsed chemical vapor deposition process, which is unique in the PET bottle plasma deposition process, can increase process flexibility, allowing the barrier layer to be more tailored to the customer's specific needs.

Since the gas by-products in the reaction can be pumped off during the process, and new desulfurization gas can be added during the pulse pause, the plasma pulse can optimize the use of post-reaction gas delivery. The coating formed by this method is characterized by excellent uniformity and high purity.

Moreover, the overall heat load of PET bottles can be significantly reduced due to plasma non-continuous combustion.

Online quality monitoring

On-line installation of process monitoring devices can control and guarantee product quality. The three-stage protection principle of the high-precision accumulating process has been practically tested in the pharmaceutical bottle production, and has been further applied and reformed in this new type of accumulating machinery. This unique process control system is used in PET plasma deposition to monitor both plasma ignition and compliance with process parameters, as well as to directly and reliably detect the presence of leaks and whether the deviations in the process are excessive. For example, if the plasma does not burn or does not meet the process parameters and other phenomena, the machine can remove the bottle. This ensures a uniform and high-quality bottle coating.