issue 05/2021

Processing
Early collaboration leads to
fast mass production
application success
Utilizing a proprietary Bio-Resin blend, the
company Refork (Prague, Czech Republic),
injection moulds sustainable single use utensils.
The bio-resin material consists of wood flour (primary
material sourced as waste from the wood industry),
PHA (binder) and various renewable minerals (to
enhance mechanical properties). This special blend is
fully biodegradable in home compost, soil, or marine
environments. Refork utensils include a selection of
forks, knives, and spoons.
Refork developed their proprietary blend that would
be suitable for injection moulding by involving Mold-
Masters (Georgetown, Canada) at an early stage. That
process involved testing various biopolymers (PLA,
PBAT, PHA’s) which would act as the binder. There were
several key variables that needed to be achieved for the
end product to be a success. This included:
• High biodegradability criteria
• have good mechanical properties,
• be acceptable for food contact,
• offer good processability,
• be visually appealing (colour/texture),
• be suitable for mass production,
• higher HDT (Heat Deflection Temperature) point.
There were 3 key challenges during the injection
moulding process that Refork needed Mold-Masters to
overcome:
1. Prevent material degradation (The bio-resin material
tended to degrade quickly during the injection process as a
result of the biopolymer binders and wood flour).
2. Achieve a consistent cycle time that could be scaled to
mass production.
3. Minimize the injection pressure to allow system
compatibility on a smaller machine.
Mold-Masters supplied several optimized Master-
Series hot runner systems (hot halves) depending on the
production capacity that was required for each product.
This included 48 and 24 drop production hot halves and a
4-drop hot half for R&D testing.
Mold-Masters TempMaster M2+ hot runner temperature
controllers were also utilized to maintain tight process
control.
Mold-Masters worked closely with Refork to supply hot
runner solutions that allowed them to successfully achieve
all of their goals. Not only was Refork able to process their
unique material, but Mold-Masters hot runners were
able to achieve a consistent cycle time, minimize
scrap and decrease the required injection pressure
by 500 bars to allow the moulds to be operated with
smaller machines. Mold-Masters hot runners are
currently used by Refork to produce over 12M Bio-
Resin utensils on a monthly basis (151M annually).
“For us, mold-masters is more than a supplier,
they are a development partner,” Josef Žádník,
CEO, Refork. AT
www.refork.com | www.moldmasters.com
48 bioplastics MAGAZINE [05/21] Vol. 16