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Whitepaper
Adhesives and Recycling:
Strategies for Improvement
baumerhhs.com
Content
Adhesives and Recycling: Strategies for Improvement .......................... 3
I. Efficient Paper Recycling: Technological Advancements and
'Less is More' Approach Can Overcome Challenges ........................ 4
II. Target and Non-Target Materials of Recycling .......................... 5
1. The role of adhesives in recycling ............................................... 6
2. “Less is more” in the recycling guidelines: .................................. 7
III. Hotmelt Applications (non-reactive) ....................................... 9
1. Criteria for the Recyclability of Hot Melts .................................... 9
2. Effective Strategies for Meeting Minimum Targets While
Maintaining Essential Requirements ................................................ 10
IV. Dispersion adhesives (cold glue) .......................................... 12
1. Criteria for the Recyclability of Dispersion adhesives ............... 12
2. Effective Strategies for Meeting Minimum Targets While
Maintaining Essential Requirements ................................................ 13
V. No Adhesives ............................................................................. 14
Bibliography ............................................................................................ 15
© Baumer hhs GmbH, Adolf-Dembach-Str. 19, 47829 Krefeld, Germany
Published: 24.05.2024
Autor: Thomas Walther (twalther@baumerhhs.com)
4
Adhesives and Recycling: Strategies for Improvement
Recycling is a process that converts unusable packaging at its end-of-life into val-
uable material to be reused in the economic cycle. This process is particularly ef-
fective for paper-based packaging, where the fibers can be recovered and used
to create new packaging material. Recycling not only helps us conserve natural
resources and reduce waste but also contributes to a more sustainable economy,
underlining the economic benefits of our collective recycling efforts.
Paper and cardboard packaging have been an essential part of our daily lives for
generations. Fortunately, many countries have recognized the importance of re-
cycling them and have established comprehensive systems for collecting them
separately from residual waste. This helps conserve valuable resources and
plays a vital role in protecting our environment from the negative impacts of ex-
cessive waste. Recycling helps minimize our consumption habits' ecological foot-
print by reducing the need for raw materials.
I. Efficient Paper Recycling: Technological Advancements and
'Less is More' Approach Can Overcome Challenges
Paper and cardboard recycling presents multiple advantages, but it also con-
fronts various obstacles. One of the most significant challenges is sustaining the
quality of fibers and efficiently separating non-paper elements. By using techno-
logical advancements, a proper packaging design and refining the recycling pro-
cesses, we can overcome these challenges and enhance the efficiency of the re-
cycling process even further.
Through continuous process improvements and greater consumer awareness,
optimal use of materials in the production cycle can be achieved. Packaging
manufacturers can also contribute to this effort by reducing the use of non-essen-
tial materials while still maintaining the necessary packaging functionality. The
"less is more" principle applies here, which means using only the minimal amount
of materials required to achieve the packaging function. By using fewer non-tar-
get materials, resources can be conserved and the amount of foreign materials
introduced into the recycling process can be minimized, which in turn reduces the
need for significant effort in removing these materials.
5
This makes recycling processes more efficient. For example, when the "less is
more" principle is applied, screening in paper processing is less burdened with
foreign materials.
II. Target and Non-Target Materials of Recycling
Figure 1 Target- and Non-Targetmaterials, eigene Darstellung nach 4evergreen, 2023
Recycling aims to recover as much paper fiber as possible in the highest quality
and with minimal contamination from foreign substances. The target material is
the fibers, while other packaging components (PC) such as printing inks, var-
nishes, coatings, adhesives, and components of the paper coating are non-target
materials (NC). These non-target materials need to be removed from the paper
pulp as much as possible, which is mostly done by screening.
The screening process in paper recycling involves two critical stages: coarse and
fine screening. Coarse screening is the initial phase, aiming to remove larger
contaminants that could damage downstream equipment or affect the quality of
the recycled pulp, such as large pieces of plastic, metal, staples, and other over-
sized debris.
Following coarse screening, fine screening focuses on removing smaller contami-
nants that were not captured during the initial stage, including tiny plastic parti-
cles, ink particles, adhesive residues, and other fine debris.
6
1. The role of adhesives in recycling
Adhesives can affect the recycling process of paper and packaging, potentially
lowering the quality of the recycled paper. However, by selecting appropriate ad-
hesives and adhering to specific conditions, adhesives can contribute to sustain-
able paper-based packaging. They are crucial in reducing the use of substrates
and enabling lightweight packaging.
Adhesives are not considered recyclable materials; therefore, it is advisable to
use them in moderation, adhering to the "less is more" principle. The amount of
adhesive used in packaging is often more than what is needed. The dimensional
stability of the packaging and the strength of the adhesive bond in the glued
seams set the minimum requirement for production quality. It's important to al-
ways ensure the stability and quality of the adhesive bond from a sustainability
perspective to prevent damage to the packaged product. In general, the produc-
tion and distribution of the packaged product consume more resources and have
a larger ecological footprint than the packaging itself. If the packaging is open or
unstable, the products inside may be damaged or destroyed. As a result, the
packaged product's valuable resources would be lost.
7
2. “Less is more” in the recycling guidelines:
“As a general principle, as for
all non-target materials of a recy-
cling process, the amount of adhe-
sives used in a given paper or pa-
perboard item should be optimised
to the minimum amount required to
achieve its function. Doing so will
minimise the amount of adhesive
that the recycling process needs to
handle.” (4evergreen, 2023)
“Therefore, the Paper Industry
would
encourage designers to:
minimise the adhesive use where
possible; (CPI, 2024)
8
“Optimize the quantities of adhe-
sives to fulfil the expected sealing
of the packaging while considering
the influence on paper recycling.”
(CEPI & al., 2020)
FEICA, the Association of the European Adhesive & Sealant Industry, acknowl-
edges the importance of minimizing adhesive consumption but notes that this
principle applies to all non-target materials in the recycling process (FEICA,
2023).
The various Design for Recycling Guidelines acknowledge the importance of us-
ing adhesives. However, a clear principle in all of these guidelines is that adhe-
sive use should be minimized to only what is necessary for packaging to optimize
recycling. This white paper focuses on methods and strategies for achieving this
optimal use.
9
III. Hotmelt Applications (non-reactive)
Hotmelt adhesives provide the advantage of rapid bonding for paper-based pack-
aging. The bonded joint can bear loads almost immediately, and hot melts bridge
gaps better than dispersion glues, making them the preferred adhesive in final
packaging.
1. Criteria for the Recyclability of Hot Melts
Even though some recycling guidelines (APA, 2021) may consider hot melts
problematic, it is increasingly accepted that they can be easily screened during
recycling as long as they meet specific size dimensions and softening tempera-
ture limits. Hot melts are not considered problematic in a standard recycling pro-
cess if they meet these requirements.
The 4evergreen Guideline (4evergreen, 2023), the German minimum standard
(Verpackungsregister, 2022), refers to the European Paper Recycling Council's
publication "Scorecard for the Removability of Adhesive Applications" (EPRC,
2018), which exempts hot melts from the need for further recycling tests if they
meet the specified conditions.
Softening temperature of the adhesive (according to R&B):
68 °C minimum
Layer thickness of the adhesive (non‐reactive adhesive):
120 µm minimum
Horizontal dimension of the application (in either direction):
1,6 mm minimum
The Austrian ARA Design Guideline recommends a deviating minimum horizontal
dimension of 2.0x2.0mm (ARA, 2022).
It is imperative to understand that these minimum requirements do not equate to
the notion that a greater amount of adhesive is superior. Rather, the quantity of
adhesive utilized should be minimized to fulfill only the essential packaging func-
tion. An excessive input of adhesive results in the unnecessary inclusion of non-
target materials in the recycling process, a heightened CO2 footprint, and aug-
mented costs associated with adhesive usage.
10
2. Effective Strategies for Meeting Minimum Targets While Main-
taining Essential Requirements
Figure 2 Left: Line or bead application; Right: Dot application (dotting)
The strategy to diminish adhesive usage by 50% entails a shift from continuous
line application to dot application, also referred to as dotting. This transition in-
volves substituting the solid line of adhesive with a series of dots, resulting in
substantial cost savings and a 50% reduction in the introduction of non-target
materials in the recycling process. Additionally, this approach reduces the CO2
footprint associated with adhesive usage by 50%.
An additional advantage of using a lower input of non-target material is that it re-
duces screen contamination during the recycling process.
11
Figure 3 The applied dots exceed the minimum requirements in horizontal and vertical direction by
at least twice. In the unpressed state, the dots have a horizontal diameter of 3-4mm applied and
6mm when pressed, with a thickness of 0.24mm.
The specifications outlined in the ERPC Code and other relevant guidelines ne-
cessitate a minimum size, which is currently being exceeded in the dotting appli-
cation mode by at least a factor of two. The unpressed dots measure 3-4 mm
horizontally, while they measure 6 mm when pressed. In the pressed state, the
layer thickness is 0.24 mm, which significantly surpasses the limit value of 0.12
mm. These findings indicate that the hot melt dot application is fully recyclable.
The dot application must effectively serve the packaging function by securely
sealing the packaging and safeguarding the packaged goods. It has been ob-
served through customer experiences and studies that an excess of adhesive is
typically applied. Heavily surpassing the requirements of the packaging function.
The substrate often represents the weakest point in this regard. Furthermore, the
dot application can enhance the adhesive bond under specific circumstances by
subjecting the initial release force multiple times. The numerous advantages in
terms of cost-effectiveness and sustainability in packaging production through
dotting warrant an evaluation of the packaging function.
It is important to consider both the advantages and potential disadvantages of
dotting. Dotting should not cause the application equipment to wear out prema-
turely due to the increased number of switching cycles. To prevent this, it is
12
recommended to use electromagnetically driven adhesive application valves1,
which are seal-less and can handle at least one billion switching cycles. In prac-
tice, they often perform even better. In contrast, the best electro-pneumatic adhe-
sive application valves can usually only handle a maximum of 150 million switch-
ing cycles.
Dotting plays a pivotal role in diminishing the influx of non-target materials into
the recycling process. The adhesive dots employed comply with the minimum re-
cycling requirements, thereby establishing their full recyclability, obviating the
need for recycling tests. Furthermore, this approach yields a 50% reduction in the
costs and climate impact associated with adhesive application.
IV. Dispersion adhesives (cold glue)
1. Criteria for the Recyclability of Dispersion adhesives
Water-based dispersion adhesives are generally conducive to recycling, provided
they are water-washable or water-dispersible. The objective is to eliminate them
during the recycling process to ensure their presence in the process water It’s im-
portant to note that the presence of water in a dispersion adhesive does not nec-
essarily mean it is washable or dispersible in water. Dispersion adhesives form a
closed film within the packaging, which is the focal point of the recycling process.
Nonetheless, most dispersion adhesives are amenable to recycling. Consultation
with the adhesive supplier is advisable. Fundamentally, the "less is more" princi-
ple applies, aiming to minimize the introduction of non-target material into the re-
cycling process to the extent permitted by the packaging's functionality.
1 Baumer hhs tesla adhesive applicator valves are a proven example..
13
2. Effective Strategies for Meeting Minimum Targets While Main-
taining Essential Requirements
Figure 4 Efficient Longitudinal Seam Gluing with Side Seam Gluing Solution and Stitching Process
The assembly of folding cartons and corrugated board packaging at high speeds
necessitates an alternative approach to adhesive conservation. In place of a con-
tinuous line of adhesive, the stitching process is employed, utilizing a sequence
of short adhesive lines. This approach yields a 50% reduction in material usage,
thereby diminishing the influx of non-target materials into the recycling process
and halving the ecological and economic costs associated with adhesive applica-
tion.
Research conducted by the PTS (Papiertechnische Stiftung Heidenau)2 has
demonstrated that the utilization of the stitching process for gluing corrugated
board packaging does not compromise its packaging function; rather, it tends to
enhance it.
2 Papiertechnische Stiftung: Fibre-based research & development | PTS Website (ptspaper.de)
14
V. No Adhesives
The option of joining packaging layers by interlocking or inserting flaps com-
pletely avoids the use of adhesives, but it often leads to a higher use of sub-
strates. This contradicts the goal of reducing packaging weight, as stated in the
Packaging and Packaging Waste Regulation. Even paper-based substrates have
an ecological footprint (water consumption, CO2 footprint), despite efforts by the
paper industry to reduce this. While there are savings in adhesives, there is a
higher consumption of paper- or board substrates. Additionally, the production
output of interlocking joints often decreases, and these joints can lead to perfor-
mance losses and more frequent disruptions in the packaging process. On the
other hand, using a small amount of adhesive enables lightweight packaging
without sacrificing performance. Therefore, it's important to compare the adhe-
sive process with adhesive-free joining processes, considering performance, eco-
logical, and economic parameters.
Thomas Walther
twalther@baumerhhs.com
Please don't hesitate to contact me or your sales partner if you have any further
questions. We genuinely want to engage in a dialogue with you and are looking
forward to an open and constructive exchange. We believe that by considering all
aspects along the supply chain, we can successfully transition to an even more
sustainable paper-based packaging function.
15
Bibliography
4evergreen. (2023). Circularity by Design Guideline for Fibre-Based
Packaging Version 2. 4evergreen, Brüssel. Abgerufen am 16. 5
2024 von https://4evergreenforum.eu/wp-
content/uploads/4evergreen-Circularity-by-Design-Guideline-
version-2.pdf
APA, A. F. (2021). design guidance for recycability. Abgerufen am 2024. 5
19 von https://www.afandpa.org/sites/default/files/2021-
08/AFPADesignGuidanceforRecyclability_FINAL_031621.pdf
ARA, A. -F. (2022). Circular Packaging Design Guideline. Wien.
Abgerufen am 19. 05 2024 von
https://www.ara.at/uploads/Dokumente/Guidelines-Circular-
Packaging/Circular-Packaging-Design-Guideline-V05_EN.pdf
CEPI, & al., C. e. (2020). PAPER-BASED PACKAGING RECYCLABILITY
GUIDELINES. Abgerufen am 19. 5 2024 von
https://www.cepi.org/wp-
content/uploads/2020/10/Cepi_recyclability-guidelines.pdf
CPI, C.-C. o. (2024). Design for Recyclability Guidelines. Abgerufen am
16. 5 2024 von
https://thecpi.org.uk/library/PDF/Public/Publications/Guidance%20D
ocuments/Recyclability-Guidelines-2024.pdf
EPRC, E. P. (2018). Assessment of Printed Product Recyclability -
Scorecard for the Removability of Adhesive Applications. Abgerufen
am 19. 5 2024 von
https://www.paperforrecycling.eu/download/882/?tmstv=171610661
5
FEICA, t. A. (2023). Adhesives in the context of paper & board recycling –
state of play. FEICA, the Association of the European Adhesive &
Sealant Industry, Brüssel. Abgerufen am 16. 5 2024 von
https://www.feica.eu/information-center/all-information-
centre/preview/1214/adhesives-context-paper-and-board-recycling-
state-play?id=0dad6ba5-c080-44b8-bcf0-
fef18dd6b764&filename=RAM-IN-M06-
039++FEICA+paper+recyclability+dossier+final.pdf
16
Verpackungsregister, S. z. (2022). Minimum standard for determining the
recyclability of packaging subject to system participation pursuant
to section 21 (3) VerpackG. Abgerufen am 19. 5 2024 von
https://www.verpackungsregister.org/fileadmin/files/Mindeststandar
d/Minimum_standard_Packaging-Act_2022.pdf