Europespecific content
Jenna Koenneke | April 2013
Food safety in tissue
converting adhesives
Why is food safety an important topic
for the tissue industry?
The tissue industry is usually not the first market which is
associated with food safety requirements for its products
and packaging.
However, this first impression is deceptive. Not only do tissue
products come into direct food contact everyday, as well the
increased used of recycled tissue paper draws the produc­ers
attention towards food safety questions.
Tissue products in our daily life
Tissue products are part of the daily life for billions of people
all over the world. In the bathroom, kitchen, hand bags or
pockets, tissue can be found in the form of toilet paper,
kitchen towels, handkerchiefs or facial tissues.
symptoms of a cold, for make-up removal or elsewhere in the
bathroom in households or away from home. As well in the
kitchen and at the dining table tissue products became an
essential part of everyday life.
In most cases, one to five different types of adhesives are
used to transform paper board and tissue paper into a functional end-product for consumers.
The use of kitchen towels and napkins illustrates why food
safety is as important in the tissue industry as it is in the food
industry. In fact, food comes into direct contact with
tissue and tissue converting adhesives in these cases.
People use tissue products in many different situations.
They become a real life-saver when people are fighting the
Tissue Converting Adhesive Applications
The four main tissue converting adhesive applications are
core winding, pick up, lamination and tail sealing. In the
majority of cases these are waterbased adhesives, which
means the carrier material or diluent of adhesive is water and
by allowing the water to evaporate the adhesive is setting.
Additionally, a tissue may contain additives such as cellulose
fiber treatment systems or fragrances. Finally, there are packaging adhesives, which are predominantly hotmelt adhesives.
Depending on the final product manufactured all or some of
the adhesive applications are part of the converting process.
Core winding
Core winding describes the process to produce paper cores
around which the tissue is wound. Tissue cores consists of
one or more strips of paper board that are bonded layer on
layer (or wound in itself) in a spiral fashion. This is a continuous
process and a blade cuts the core into logs of up to three meters
(approximately the length of the tissue mother roll).
Lamination
As the word itself suggests, in lamination different layers of
tissue are bonded together to increase bulk and softness of the
tissue product. In converting, this process step usually combines
laminating and embossing (functional as well as decorative).
Pick up
In the rewinding process, the laminated tissue is wound
around the core. Pick up describes the process steps where
with the help of an adhesive the first sheet of the tissue is
fixed to the core.
Tissue converting adhesive applications.
Tail sealing
At the beginning of a finished tissue roll the end sheet is glued to
the remaining tissue on the role. In the converting process this is
called tail sealing and takes place towards the end of the converting line before the logs are cut into the size of the final tissue roll.
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Schematic tissue converting process (adhesive-relevant extract).
Core accumulator
Transfer of wound
cores to the winding area of rewinding
station
Core winder
Winding ans gluing of
paper board strips including cutting into logs
Printing unit
Printing and eventually
application of additives
(e.g. softener, perfume)
Laminator-embosser
Gluing and embossing
of tissue layers
Unwinder
Unwinding tissue
from mother roll and
arranging of layers
Rewinder
Winding of laminated and printed
tissue around cores
Accumulator
Transfer of
rewound product
logs to loader and
saw
Log loader and saw
Positioning and cutting
of rewound logs into final
tissue rolls
Requirements in Tissue Converting
Tissue converting lines vary in size and speed. A bigger line
can be several meters high and even longer. Speeds can go
up to 700 meters per minute in the converting line.
Adhesives have to match the requirements of very high machine speeds, clean application without stringing or splashing,
excellent wet tack, short setting and be compatible different
tissue and paper board qualities, while at the same time being
fully water dispersible for the recycling process and easy
cleaning of machines.
paper board of cores nor the laminated layers are supposed
to separate easily before the recycling process, good dry release
is an important factor for pick up and tail sealing adhesive performance and end-user functionality.
Increasing speed of converting lines, use of recycled materials
and different tissue or paper board qualities confront adhesive
product developers with the challenge to constantly and proactively improve adhesive formulations. At the same time, the
food contact status and maximum concentration levels of raw
materials are changing.
The profile per adhesive application varies as well. Whereas
very high adhesion and bond strength are important for core
winding and lamination adhesives because neither the wound
Raw Material Evolution
The raw material basis of tissue converting adhesives has
been changing over time to improve machinability and to
increase safety of the products.
For example in the past, dextrin was the basis of many core
winding adhesives. The light-colored powder is commonly
produced from corn, potato or wheat starches.
Over time, the adhesive basis moved more and more towards
synthetic polymers like polyvinylacetat (PVAc), among others
to meet increasing performance requirements from the industry.
It is however not only the chemical basis that developed over
time. Adhesive formulations consist of many different ingredients
and often the ones that constitute only a small part of the formulation are the ones monitored most closely.
They give the adhesive very specific features (e.g. very high
wet tack) or might as well influence the shelf life, overall film
properties (e.g. flexibility) or machinability (e.g. anti-foaming
additives). As in the water-based adhesive business for the food
industry, plasticizers and preservatives are examples of raw
material groups that are investigated closely with regard to
their suitability for food contact approved adhesives.
The overall perception that natural raw materials are safer or
better than synthetic raw materials is not necessarily correct.
Using synthetic raw materials can even increase the control an
adhesive producer has over its origin, composition and purity.
At Henkel in the development of tissue converting adhesives,
the formulating chemist always selects from a list of raw mate­
rials that is in line with FDA and BfR XXXVI (Paper and board
for food contact) requirements to make sure all newly developed products can be used for all final tissue products. Additionally, formulations may be changed or adjusted if changes
in the relevant regulations and guidelines occur.
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New standards in terms of safety
Although the importance of food safety in tissue converting is not as straightforward as it
appears in the food packaging industry, the use of tissue products especially of kitchen towels
and napkins illustrates why it needs to be on list of base requirements in the tissue industry
as well. The overall raw material landscape, industry performance requirements as well as the
list of approved raw materials is constantly changing. Henkel targets to set new standards in
terms of safety as well as performance and to anticipate future developments.
Impact of new regulations on
the selection of raw material
Developing new adhesives for the tissue industry means
satisfying technical requirements to match expected performance as well as to assure a safe use in the converting
process, for the end user and the environment. Henkel is
fully committed to this mission for both; the next generation
products and all currently active products.
A relevant factor impacting raw material selection to be noted
is related to the recent developments regarding some boron
compounds like boric acid and borax (disodium tetra­borates).
Since 2010 and due of the implementation of REACH Regulation (CE) n. 1907/2006 and CLP Regulation (CE) n. 1272/2008,
boric acid and borax have been classified as potentially
damaging fertility if exposed to in large quantities and they
have been added to the Candidate List of SVHC (Substances
of Very High Concern). The two compounds are
commonly used in the tissue converting industry for core
winding adhesives. Boric acid is used in waterbased synthetic
adhesives and borax is used in borated dextrin adhesives.
The function of these substances is related to significantly
increasing the wet tack and setting speed of the adhesive,
which is for example especially important for high machine
speeds. Although generally the content of these substances
in all involved formulations is far below the limits of concern
or hazardousness, a fast process of replacement has already
been successfully implemented in order to generate a
specific range of products free from these chemicals.
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Jenna Koenneke’s professional background is international business with a focus on
marketing. In her professional career, she focused on industrial marketing. In 5 years
with Henkel, she has worked in various market segments including Graphic Arts and
Tissue and Towel. Today, she is responsible for marketing of Consumer Packaging
Adhesives with the majority going into the food and beverage industries.
Key take away
• The increased use of recycled tissue paper
draws the producers’ attention towards
food safety questions.
• Adhesives have to match several requirements, i.e. very high machine speeds,
clean application or excellent wet tack.
• In most cases, one to five different types
of adhesives are used to transform paper
board and tissue paper into a functional
end-product for consumers.
• Henkel is fully committed to developing
new adhesives for the tissue industry that
assure a safe use in the converting process, for the end user and the environment.
• The four main tissue converting adhesive
applications are core winding, pick up,
lamination and tail sealing.
Henkel AG & Co. KGaA
D-40191 Düsseldorf
www.henkel.com/foodsafety
The information provided herein, especially recommendations for the usage and the application of our products, is based upon our knowledge and experience. Due to different materials
used as well as to varying working conditions beyond our control we strictly recommend to carry out intensive trials to test the suitability of our products with regard to the required
processes and applications. We do not accept any liability with regard to the above information or with regard to any verbal recommendation, except for cases where we are liable of gross
negligence or false intention. The information is protected by copyright. In particular, any reproductions, adaptations, translations, storage and processing in other media, including storage
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otherwise noted, all marks used in this sell sheet are trademarks and/or registered trademarks of Henkel and/or its affiliates in the US, Germany, and elsewhere. © Henkel AG & Co. KGaA,
04/2013