Our responsibility to this planet is at the heart of every decision we make, and we’re responding to this pressure by dedicating ourselves to what we do best – creating paper solutions that perform like plastic but protect the environment. We believe in tomorrow, so we’re doing everything we can to ensure the next generation of paper arrives today.
In our paper laboratory, we use fit-for-purpose base paper substrates from the delfort portfolio and apply application specific coating formulations.
We follow clear design guidelines and try to maximize the renewable content as well as minimize the overall coating thickness in relation to the paper grammage.
We are seeking the best balance between the required shelf-life and food safety as defined by the target packaging application and good recyclability.
The coated sheet samples are then characterized on their barrier performance with state-of-the-art analytical methods.
It is essential to mention that we not only perform barrier measurements on flat sheets but also on folded sheets to draw conclusions on the crack resistance of the coating (often referred to as deadfold).
The better the plasticity of the coated paper, the better the runnability on packaging lines and thus the shelf-life performance of the packed good.
A good first indication of the quality of the applied coating is the water and oil absorbency of the material under standard conditions. This is measured via the Cobb Test which tests the amount of liquid that a defined area of the substrate absorbs after a certain time (typically 60sec, 5min, 30min). The less fluid the paper absorbs the better the performance of the packaging material against water and vapor loss as well as intake. Both gradients (inside-out and outside-in) are crucial to keeping the packed goods fresh or crispy over the required shelf life.
An excellent quick test to characterize the coverage and the defect density of a coating (“pinholes”) is the oil test. Pinholes can be quickly visualized through oil spots on the backside of the substrate.
To determine the oil and grease resistance (OGR) of the coating, KIT testing (according to the TAPPI standard) was traditionally used. The wetting behavior of different liquids and solvents results in a specific KIT value between 1 (weak) and 12 (excellent). Since KIT testing can falsify the OGR of PFAS-free coatings, we also verify OGR with the palm oil test. Here the time taken for a simulated fat drop (the palm kernel oil) to penetrate the sheet of paper gives an excellent indication of OGR.
Vapor, Oxygen & MOSH/MOAH
For high-barrier applications with long shelf life requirements, it is essential to determine the barrier against moisture/water vapor (MVTR) and oxygen (OTR). We use very sensible devices from Mocon to measure the MVTR and OTR of different coatings at different conditions (typically 23°C resp. 38°C and 50-90% humidity) to simulate the shelf life performance in different climates.
In short, we precisely measure the transmission rate of the vapor resp. gas through a defined area of the coated paper in gram resp. cubic centimeter per square meter per day.
Additionally, we use the HVTR value, the hexane transmission rate, to get an excellent indication of the barrier performance against oxygen, most aromas, and also mineral oil saturated and aromatic hydrocarbons (MOSH/MOAH).
Polar & Non-Polar
A good barrier against water and vapor (a polar substance) and a good barrier against oxygen and most solvents (nonpolar substances) can hardly be realized in a single coating layer.
Our reel-to-reel pilot coaters enable us to apply our own coating formulations with different coating & printing technologies up to a speed of 50m/min. We can also adjust the drying and cooling to optimize the runnability of the coatings.
Again, we verify the barrier performance on a reel level in our paper laboratory. The goal in stage 2 is fulfilled when we can successfully repeat, or even improve, the performance compared to the sheet level.
We run a coating kitchen with several small batch dispergers, mixers and cookers to prepare our proprietary coating formulations for the subsequent coating step. Additionally, we have the possibility to remove entrapped air in the formulations (degassing), to store the prepared batches in storage and working tanks and to directly feed the liquids to our pilot coaters.
Recyclability as a key condition for any barrier paper
The recyclability of our barrier products is one of the most important sustainability claims for paper as a replacement to plastic film in flexible packaging applications. It is essential to quickly verify the recycling performance of our prototypes before we proceed with our product development process of packaging and shelf-life tests.
We can do so in our RPC and our team has even been trained by the Papiertechnische Stiftung (PTS). We can determine recyclability according to PTS, Aticelca and the new CEPI method.
After we have verified the barrier performance targets on a reel level and we have proven recyclability, we pass the development gate and the prototype makes it to the next stage in the product development process.
For our customers, we need to ensure the runnability on conventional packaging lines, the transfer of the barrier performance without loss from reel to package level as well as a reliable sealing performance, either with adhesives or under elevated temperatures with a heat seal.
We understand our R&D mission not only in the development of barrier papers but also in enabling our customers to quickly transfer from conventional film materials to paper. This is why we have set up a packaging laboratory where we operate our own HFFS packaging machine. This enables us to not only create packaging mock-ups for our customers but also to define a realistic process window with our material on packaging lines. We look into maximizing cycle times, ensuring tight sealings, and minimizing the mechanical impact of machine components on our barriers.
Naturally, food safety is a top priority for our customers and is secured through the packaging.
Testing our barrier paper packaging with different food and non-food products in different conditions, we support our customers by verifying the quality of the products after the shelf life duration. We foster collaboration with international food research centers to provide nutritional services (like microbiology analyses, active water testing, and tasting panels) to our customers if necessary.
Our regulatory team leads the process of collecting all relevant data for claiming compliance certificates for our prototypes (for food applications e.g. BfR, FDA).
Upscaling & industrial production
Our partner delfort operates various paper machines with online coating capabilities as well as stand-alone industrial coating machines. Our work continues after the proof of concept on a prototype level. We have a collaborative upscaling team at delfort that is responsible for expanding the developed solutions to an industrial level.
Additionally, we collaborate with international upscaling facilities and contract coating service providers to evaluate new coating technologies on semi-industrial levels. This generates marketable solutions for almost any paper packaging application.
Paper Packaging Markets
Together with delfort’s Business Development Team, we continuously screen the flexible packaging market for applications with a high paper conversion probability. We focus on aqueous based dispersion coated papers to realize the required barriers and functions for flexible packaging applications with excellent recyclability and cost-performance-ratio.
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