Siegwerk’s CIRKIT coatings: pioneering sustainable solutions with UPM and DG Press for a circular future Oliver Waddington, Global Business Development Lead, Circular Economy Coatings (CEC) Business Unit, Siegwerk

PAPERTECHNOLOGYINTERNATIONAL
Strengths:
• Greater Flexibility: Offline coating allows for
customization of coating formulations, layer thickness,
and application techniques, making it suitable for a wide
range of products and substrates.
•
Enhanced Coating Quality: Offline processes
often provide more precise control over coat weight,
coverage, and drying, resulting in a homogeneous,
defect-free surface.
•
Multiple Coating Layers: Offline systems can often
apply multiple layers of coatings, including primers,
functional layers, and topcoats, to achieve complex
performance requirements.
•
Post-Printing Coating: Offline coating can be applied
after printing, enabling additional functionalities or
protective layers without interfering with the print
process.
Weaknesses:
•
Additional Processing Step: Offline coating adds
an extra step to the production process, increasing
handling, logistics, and overall production time.
•
Higher Production Costs: Due to the additional
equipment, labor, and energy required, offline coating
can be more expensive than online processes.
•
Best Fit: Offline coating is ideal for specialty
applications that require high customization and/or
high barrier, such as more sensitive food packaging, or
products with specific orgaleptic requirements.
3. In-Line Varnishing
In-line varnishing refers to the application of a thin layer of
coating (or “varnish”) directly on the substrate during the printing
process, typically using 昀氀exographic, rotogravure, or offset printing
presses equipped with varnishing units.
Strengths:
•
Seamless Integration: In-line varnishing integrates
coating into the printing process, reducing production
time and eliminating the need for separate coating
equipment.
•
Cost Efficiency: By combining printing and coating
in a single pass, in-line varnishing reduces handling
and logistics costs, making it a cost-effective option for
many applications.
•
Customizable Performance: In-line varnishing
allows for selective coating application, enabling spot
varnishing, patterns, or areas with different finishes
(e.g., gloss vs. matte).
Weaknesses:
•
Lower Coatweight: In-line varnishing typically applies
a lower coatweight compared to dedicated coating
methods applied online or offline.
•
Limited Drying: Printing presses are often limited in
the amount of drying capacity they have, which may
restrict their use for some formulations and/or for
applications requiring higher coatweights.
•
Best Fit: In-line varnishing is ideal for some lower
barrier packaging applications where smaller, more
flexible batch sizes are needed. Additional, using in-line
varnishing to add top-up functionality to precoated
papers is a great way to tackle some of the most
demanding packaging applications; whether enhancing
barrier performance, adding heatseal, or even
managing physical properties, such as CoF or heat
resistance.
By understanding the strengths and limitations of each
coating application method, packaging manufacturers can make
informed decisions on how to best functionalize their paper-based
packaging for specific end-use applications, and brand owners can
understand the partners needed to enable a successful paperization
transition. Siegwerk’s CIRKIT range includes products compatible
with all these methods, providing flexibility and performance across
the entire value chain.
Summary of coating application methods
Method
Online
Coating
Offline
Coating
In-Line
Varnishing
Strengths
Weaknesses
Best Fit
High speed, cost-effective,
optimized barrier performance
Limited flexibility, high setup costs
High-volume packaging
with barrier needs
Customizable, precise control,
multiple layers
Additional processing, higher costs
Specialty and luxury
packaging
Seamless integration, costeffective, print protection
Limited barrier performance, lower
coat weight
Consumer goods and
promotional packaging
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