Some more notes on barriers in packaging solutions for PET today!
LOGOPLASTE and LOGOPLASTE Innovation Lab have always been involved in almost all of the technologies available on the market, either in terms of pure technical evaluation, industrial implementation, or as a co-partner for technology development.
In particular, LOGOPLASTE Innovation Lab is responsible for supporting the evaluation and progress of technology in this field for LOGOPLASTE. The goal of this involvement has always been to be a market leader and to be aware of the best solutions for different packaging requirements (light, O2, CO2, and water vapor). The information shared here reflects interactions with resin suppliers, master batch suppliers, additives, industrial equipment/technology suppliers, end users, universities, associations, and brand owners. This article has the objective of sharing some of the principles and ideas that drive LOGOPLASTE’s position in the market. It is the second paper produced by LOGOPLASTE Innovation Lab in this field and complements the last internal document produced 3 years ago.
Barrier needs? Not much has changed!The main needs for barriers are linked to the “Fabulous Four”: -Oxygen ingress -Water vapor (ingress/loss) -CO2 loss -Light protection
Oxygen ingressThis includes juices, dairy products with added juices or vitamins, water with added juices or vitamins, some energy drinks, etc.
Water vapor (ingress/loss)Here we can point to many products. With the exception of products like powders, this is a field that most people tend not to have direct experience with. Most products are overfilled to ensure that over the shelf life of the product, the consumer is buying the quantity indicated on the label. This is particularly true for PET as the permeability is substantially worse than HDPE or PP (Table 1).
In some products, overfilling can range from 5 to 10%, depending on the specific shelf life of the product. For products with a higher value than water, this can make a big difference.
CO2 lossIn this range of products, we normally talk about CSDs.
Light protectionThis includes products that are sensitive to light/UV radiation. Milk is probably the most interesting at the moment, and we will take a closer look at this subject later. While there may be some “specialties” or products where other factors must be considered, these four factors cover most of the critical aspects from a bottle perspective.
Barrier behavior – The basic principlesIn term of O2 and CO2 barriers, the principles are very simple. The following types of barriers are typical: Passive: mono material / combination of materials (blends, multi-layer or additives) / coatings Active: blends / multi-layer Passive + Active (possible combination of the above) The behavior of the above combinations can be illustrated in a schematic way highlighted in figure 1 and figure 2. The graphs show the behavior for O2 barrier application. For CO2, the principles shown in the Passive Graph are basically the same .
Active barriers (mono and multi-layer)Here the additives typically added to the structure of PET will “capture” the oxygen. The most interesting feature of these additives is that they typically capture oxygen that is trying to enter the bottle, but there are other factors that can influence: -the PET structure -the filled product -the head space This is obviously worth noting, as it enhances the performance of barriers to 02. It is also the reason why this technology is preferred for products that are sensitive to 02.
Active + passive barriers (mono and multi-layer)For some applications, combining both additives can produce interesting results. This is why we also find some products with barrier performances as described in Figure 3. These three combinations are basically the main solutions available on the market, delivered on different technological platforms. Let’s now take a look at what is new and what can make a difference.
What is new in barrier technologies?The most relevant and interesting developments are: -Light barrier applications for dairy products -New generation platforms for multi-layer -New materials
Light barrier applicationsThere have been very interesting developments in this field in recent years. The first real industrial volumes have started to appear, and many different solutions are emerging as alternatives to the traditional TETRA BRICKs used for milk. Particularly for the UHT market, we are reaching a point where some of the solutions are cost competitive against BRICK and EBM 3 layers (the traditional white/black/white). Today, three PET solutions are being used for UHT Milk. Each of the solutions has pros and cons, and there is no universal solution (Figure 4). Some notes on the three different processes (Table 2).
Each industrial case should be considered individually, and the specific details of each project will dictate the most appropriate solution (Figure 5).
There are some parallel points that will determine the future of this market for PET: -Concentration of volumes of production in the milk market -Sustainability and recycling streams -New generation platforms for multi-layer -New materials