JEC COMPOSITES MAGAZINE - Issue #86 - January/February 2014 - 29

paper

Efficient prepreg processing

Hockey sticks and skis are not the products that leading global papermaker Sappi is usually associated with. However, the
company's speciality paper Algro® Sol was also developed to
support the manufacture of such sporting goods along with other
products in the expanding prepreg market. In addition, the company has increased its production capacity in order to meet the
growing market demand for this grade.

Gunnar Sieber
Product Group manager, Release liner
Sappi Fine Paper Europe

The role of paper in
prepreg production
Prepregs are pre-impregnated fibre materials. The fibres can be glass or carbon and
are generally formed into mats. The fibre
mats are then impregnated with a resin
sizing, resulting in an integrated substrate.
The mats can be heated to make them
flexible for further processing. Special process paper is applied to both sides to safely
transport and store the pre-impregnated
fibre mats. This process paper has to be
anti-adhesive on both sides, and this is
generally achieved with a silicone coating.
The siliconised process paper ensures that
the resin-sized fibre mats can be easily
removed from the process paper. Prepreg
mats are rolled up with the siliconised
process paper and can later be unrolled
without being damaged since the silicone
on the respective paper sides has differential release characteristics, meaning the
process paper will not stick to itself and is
easily removed.

Prepreg processing
- easy and fast
Algro Sol is a base paper ideal for siliconising or for use as a protective carrier for
a fibre mat made of glass or carbon and
resin. Once the mats are safely transported
to the manufacturing location, the resin is
shaped/laid-up into the final product.
To ensure delivery without damage and
easy release of the mat resin from the siliconised process paper, coated Kraft paper
with reverse side functional coating is an
effective and protective substrate. A typical CCK (clay-coated Kraft) base paper is
constructed as shown in the figure below.
The coated mat finish of Algro Sol papers
offers a controlled surface to anchor the
silicone. It is compatible with solvent-free
(thermal, EBC, UV), solvent-based and
water-based silicone systems and ensures
high ply bond strength and uniform calliper.

Typical construction of Algro Sol Paper

No86 January - February 2014 /

Feature Prepreg

he timing of Sappi's focus on this
market segment couldn't be better,
according to management consulting and market research firm Lucintel.
The firm's competitive analysis of the
global prepreg market and its usage, as
reported in Global Prepreg Market 20132018: Trend, Forecast and Opportunity
Analysis, projected robust market growth
between 2013 and 2018. This market segment is predicted to reach US$6.1 billion
worldwide by 2018.
The segment's growth was largely attributed to the rising costs of raw materials,
but the study also pointed to high growth
opportunities for prepreg applications
in aerospace, automotive, and civil
engineering. Growth opportunities are
also aligned with population expansion,
resulting in an increasing number of users
for prepreg-based items. In addition, there
are new materials coming onto the market
that are created using pre-impregnated
fibres, and this will result in a wider range
of end-user products. Sappi is just at the
beginning of a large market opportunity
and does not know how big exactly the
market will be, but is positioning itself
to address what will probably be a fairly

significant opportunity. This is why the
company has developed the Algro Sol
paper and is committed to offering a productive and efficient solution. This paper
was specially formulated to deliver quick
release properties for the careful handling
and transportation of prepreg materials.

jec composites magazine 29

JEC COMPOSITES MAGAZINE - Issue #86 - January/February 2014

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