Issue 04/2016

Toys
bioplastics for the toy market
Adding to the challenges are the perceptions that bioplastics
by their very nature are designed to be disposable. As a
research model, Solegear focuses on developing bioplastic
formulations using existing, readily available biopolymer
building blocks and combining them with appropriate additives
and fillers to meet certain performance characteristics, all
the while maintaining the highest possible biobased content,
no chemicals of concern and low CO 2
footprints. In 2014
when Solegear turned its attention to developing a material
replacement for a typical ABS used in toys like building bricks
or figurines, the Company used the Lanxess Novadur 650
as the baseline reference material for targeted properties
(see Table 1). A rigorous screening process was started that
would deliver strong sustainability benefits, but also prioritize
the long-time durability of the bioplastic material. An extradurable
formulation was the main objective.
An ambitious Design of Experiments (DOE) plan was
developed for a wide discovery phase that would combine
a variety of biopolymers and polymers with some additives.
As expected, combinations of several different types of (bio)
polymers delivered both miscible and non-miscible options.
Over 100 different formulations were individually compounded,
molded and tested in laboratories using an iterative process.
With each iteration, biopolymers could be accepted or rejected
to narrow the search based on targeted specifications. The
formulations in development were all compounded using
twin-screw extruders; however, processing pellets into
testing specimens, including tensile bars and molded parts,
presented a somewhat different challenge.
Where needed, twin–screw reactive extrusion was the
preferred method for compounding pellets of each formulation.
From these pellets, different testing bars were injected.
Tensile, flexural and IZOD impact were the principal properties
evaluated according to ASTM standards. Regardless of
academic or small-scale lab research throughout the process,
scaling-up using industrial equipment is always extremely
challenging. After successful lab-scale results, selected
formulations were run and tested on a small industrial line,
with only minor processing adjustments being made along
the way. The final successful formulations have now been
commercialized under the name of Traverse ® XD1000 series.
The principal mechanical and thermal properties have been
compared with those of Novadur ® 650 as shown in Figure 1.
Traverse XD formulations deliver similar impact values,
higher stiffness (rigidity) and an important increase in ductility
(typically over 250% elongation at break vs approximately
20%). One particular formulation exceeded the expectations
of the R&D team to deliver what has been affectionately
nicknamed super tough, with high strength, high impact
resistance and high ductility all combined. Some differences
have been noted regarding shrinkage rate, which is slightly
By:
Michel Labonté
Solegear Bioplastic Technologies Inc.
Vancouver, BC, Canada
Both photos provided for illustrative purposes only,
not actual Solegear products
bioplastics MAGAZINE [04/16] Vol. 11 33