Story
Covestro barrier coating resins help us to create a better environment
It is time to switch to more reusable packaging
The fast pace of modern life makes food and beverage packaging essential for all of us – from that takeout coffee in the morning to the sandwich we buy for lunch, and maybe our evening meal too.
We use so much food packaging material that it has become a considerable part of the overall packaging industry.
Sadly, most food packaging still uses unsustainable Polyethylene (PE) materials. The composites of extrusion polymers such as Low-density polyethylene (LDPE) are a common example.
Materials such as LDPE do a good job at protecting the food inside the package while providing essential functions like oil/ grease and moisture resistance.
But they are difficult to recycle economically. So, most PE-extruded packaging ends up going to landfill, where it can take 500 to 1,000 years to degrade. Just think how harmful that is to the long-term health of our planet.
The performance you need and it is kinder to the environment
At Covestro, our mission is to create products that enable safer and more sustainable food and beverage packaging for decades to come.
Our portfolio of barrier resins offers a recyclable alternative to LDPE coatings. Our multi-functional resins are easy to formulate and are resistant to water (WVTR & COBB*), grease, oil and moisture. Also, they are easy to re-pulp, with almost all the fiber being recovered.
Covestro offers a fast and easy transition from PE laminated stock, and with hardly any loss in performance, that can be used on existing machinery.
Water Barrier (MVTR / COBB)
Protection for beverages
Water absorption and humidity
The amount of water and moisture the surface of a material can take up in a certain time is measured by two different tests.
WVTR / MVTR
Water vapor transmission rate (WVTR) tells us how much moisture is able to pass from a material’s interior surface to the outside.
This is determined at specified conditions of temperature and relative humidity, and expressed as grams per square meter per day: g/m2 /24hr (ASTM F 1249 at 38°C and 90% RH, BS 3177 at 25°C and 75% RH, DIN 53122 at 23°C and 85% RH).
All our MVTR / WVTR tests are conducted using MOCON technology which delivers extremely accurate results by combining precision temperature and humidity control with highly-sensitive sensors.
Cobb testing: Measuring water absorption
Cobb Sizing Tester determines the amount of water absorbed by paper, cardboard, corrugated fiberboard, paperboard, in a specified time under standardized conditions. The levels of water absorption help evaluate various characteristics of paper (such as sizing, porosity, etc.).
A sample of water is placed on the top of a beaker containing water. Then the beaker is flipped so the water comes in contact with the material. At specific time intervals, the sample’s weight is determined.
Results from the Cobb test show that board (especially boxboard made from recycled fiber) is extremely sensitive to atmospheric humidity and must be stored at a maximum of 50% relative humidity, which often means using air-conditioned warehouses. This is because water-damaged board will bend and become unsuitable for printing or box manufacture.
Reworkability
Recycling and repulping combined
RecyclabilityReworkability is a combination of recyclability and repulpability. And recyclability refers to the capability of used paper and paperboard, including in-plant waste, and post-consumer waste, to be processed into new paper or paperboard.
Repulpability
This refers to the capability of material to be re-wetted and fiberized to form new sheets.
Heat seal
The parameters that determine an effective heat seal
Seal limitIs the minimum temperature needed for a proper seal at given times and pressures. This is normally expressed in °C and may refer to the machinery used to carry out this test e.g. Otto Brugger.
Seal window
These are the maximum and minimum temperatures between which proper seals can be formed on packaging. The window is expressed as a range of °C. Optimal seal windows often refer to the running speed of the film on the production line. This range normally becomes narrower – and seal temperatures higher – as line speed increases. You may see seal windows described in terms of branded machinery.
Seal strength
The seal strength is the maximum force needed to tear a specified width of a seal. It is expressed as force per width e.g. N/25mm.
Grease/oil retention & contamination prevention
Keep the good in and bad out
Grease leakage typically causes dark spots to form on the outer layer of the paper or board. Grease resistance can be improved by the degree of grinding of the fibers, and coatings used.
There are several tests that will determine the grease resistance of the board. One of these is the Kit test. In this test, a drop of fluid is put on one side of the board. The composition of the fluid corresponds to a certain Kit value. The time it takes for any spots to appear on the other side of the board can be measured, and subsequently correlated into a measurement of a material’s grease resistance.
Kit test data and results are available for all of our resins.
Low odor
Food odors: as intended
Foods that are sensitive to odor issues will require the correct packaging. If these foods are not suitably packaged, they can represent an economic and health challenge to the manufacturer.
Foods that are sensitive to odor issues will require the correct packaging. If these foods are not suitably packaged, they can represent an economic and health challenge to the manufacturer.
We have reduced the residual monomer levels used in our resins to some of the lowest levels, in order to make any odors present in packaging as neutral as possible.
This means the end consumer can enjoy the food or beverage experience as the manufacturer intended.
Our resins are more than a match for LDPE
In both factory and field tests, products created using our Covestro resins have shown to be as effective as those made with traditional, less eco-friendly materials. Our stringent quality control procedures ensure that all our products offer a high level of performance.
