The future of monomaterial flexibles

Recyclable packaging that protects

As concern around natural resource depletion increases for businesses and consumers alike, so does the drive toward a circular economy, where recycling is a fact of life. For the packaging industry in particular, recyclability is no longer a ‘nice extra’, but an essential.

However, achieving this can be challenging for packaging manufacturers, especially when it comes to flexible barrier packaging, such as retort pouches and multilayer laminate. Often, recycling this packaging requires separating various polymers and metal foils – which can be expensive or impractical. Manufacturers face the challenge of simplifying their flexible barrier packaging. This often involves moving toward monomaterials constructed from similar or identical polymer grades that can be recycled as a single substance.

Nevertheless, many traditional monomaterial packaging solutions fail to deliver the levels of functional performance that consumers expect. Specifically, maintaining sufficient barrier performance – the ability to keep food or other perishable goods safe – is a key concern in reduced-material or monomaterial designs. In line with the growing need for monomaterial solutions that retain functional performance, Covestro offers a portfolio of coating resin solutions. These enable manufacturers to replace extra material layers with thin functional coatings – enabling high-performance monomaterial packaging.

An extensive range of monomaterial solutions

To ensure barrier performance, packaging manufacturers need solutions that provide features such as sealability, heat resistance, and protection from odor and mineral oils. 

Our monomaterial solutions portfolio addresses each of these needs, and includes primers and topcoats – so, whatever your requirements, we can provide a solution: primerslamination adhesivesheat-sealable solutions , heat-resistant topcoatsprotective topcoatsmineral oil barriers, organoleptic, aroma, and flavor barriers.

 

What is a monomaterial?

A monomaterial contains predominantly one material type, such as PE (LDPE, LLDPE, HDPE), PP, PET, or paper. (Ceflex) For plastics, this should mean over 90% of one polymer type, as this is the upper threshold when adhesives, additives, and inks are included.

On many materials, acrylic coatings are typically used to improve the surface for printing, to improve sealability and seal integrity, and to prevent scratching and improve the overall material’s toughness. To be classified as a monomaterial, the material can contain a maximum of 5% acrylic coatings. 

Film and flexible packaging substrates

Traditionally, monomaterials’ functional performance has been particularly limited in flexible packaging, which has often relied on the use of several layers. Whatever your packaging material, Covestro can provide a solution for you. Our coating resins can add protective features to a wide range of film and flexible packaging substrates.

BOPP (biaxially oriented polypropylene).
BOPE (biaxially oriented polyethylene)
BOPET (biaxially oriented polyethylene terephthalate)
PLA (polylactic acid)

Maximum functionality in key performance areas

Of course, packaging manufacturers also need to ensure high functionality in areas beside barrier performance and recyclability. Our monomaterial packaging solutions offer all the key properties our customers expect, including:

Blocking free | Heat-sealable | Good adhesion | Printable |
High transparency | Surface enhancement | Food contact compliance

Our portfolio

Whether it’s primer or topcoat, and whatever barrier function you need, our portfolio of monomaterial solutions has the answer for you.

Adhesives for lamination

Materials can be combined to customize packaging functionality to suit the product or environment where it will be used. This offers a lot of flexibility, and adhesives play an important role in this. It’s important to keep the total amount of adhesives used below certain thresholds, to prevent it hurting the recyclate quality. Adhesives can reportedly cause gel formations during the extrusion process, which can reduce the recyclatequality and block the screen filters on the extrusion line. Adhesives, such as polyurethane, acrylic, or natural rubber latex adhesives as well as non-PE- or non-PP-based tielayers, can comprise a maximum of 5% of the total structure’s weight. The limit is to optimize the quality of the recyclate and to avoid disruption of the recycling process.

Available grades for lamination adhesives: NeoRez® PL-806 (EMEA), NeoRez® P-925 (EMEA) and NeoRez® P-900 (EMEA).


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Primers (for topcoat adhesion or for metallization)

Primers are initial coatings applied to a substrate to improve the adhesion of the following layers or coatings, to increase their durability, and to provide additional protection for the substrate. In particular, primers are always required with heat-sealable coating layers, which can enable sealing on stretched and oriented BOPP and BOPET film, to achieve the required strength and consistent adhesion.

Available grades for primers: NeoCryl® A-1127 (EMEA & NMA) (metallization), NeoCryl® BT-36 (EMEA & NMA) (metallization), NeoRez® R-605 (EMEA & NMA) and NeoRez® R-670 XP (EMEA).


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Topcoats

Packaging has a long journey to make before it reaches the shelves. And, when being handled or transported, its protective features might be weakened through scratching, condensation, or extreme temperatures. In particular, the barrier properties of film packaging can severely deteriorate in these conditions. For this reason, the protective topcoat layers that protect the barrier are as important as the barrier itself.

Available grades for topcoats: NeoCryl® A-1127 (EMEA & NMA), NeoCryl® A-1129 (NMA), NeoCryl® A-2092 (NMA), NeoCryl® BT-67 (EMEA & NMA), NeoCryl® BT-36 (EMEA & NMA), NeoCryl® FL-715 (EMEA & NMA), NeoCryl® FL-721 (EMEA & NMA) and NeoCryl® FL-736 XP (EMEA) and NeoCryl® XK-14 (NMA).                                        

Topcoats for protection

Topcoats for heat-sealing

Topcoats with aroma and flavor barriers

Topcoats with mineral oil barrier


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Building on a tradition of innovation

To develop the solutions in this portfolio, we have built on our long history of creating high-performance resins that meet customer and market needs. In fact, we’ve long been at the forefront of innovating coating solutions for the packaging sector. High-performance monomaterial packaging is just one example of the trends we continue to set using the latest coating resin technology.

And we aren’t stopping there: we’re already developing the next generation of monomaterial solutions through our core research program. What’s more, because all our innovation is guided by our customers’ needs, we actively involve them in our R&D efforts by visiting them regularly, involving them in technical discussions, and developing new resins together. Indeed, we can also offer you solutions tailored to your precise needs – so, no matter your requirements, we’ve got you covered!

To learn more about developing these solutions together, get in touch with us.