Issue 01/2021

Foam
PLA in cold chain
transportation
By:
Steven Wu & Henter Lee
Guangzhou Bio-plus Materials Technology Co., Ltd.
Guangzhou, China
Incubators are widely used in cold chain transportation,
especially in today’s life of highly developed e-commerce
and direct supply of fresh products. How to deliver fresh
foods to consumers has become a special concern of many
e-commerce platforms, fresh food producers, and logistic
companies.
In traditional cold chain transportation expanded
polystyrene (EPS) and expanded polypropylene (EPP)
incubators or cross-linked polyethylene (XPE) insulation
bags are generally used. However, these incubators are
very difficult to recycle after being delivered to consumers,
so they are discarded as garbage in most cases, which
makes it a plastic pollution risk. Some enterprises in
Europe and New Zealand make and sell EPLA (expanded
PLA) incubators. However, due to the high melting point
and low crystallinity of PLA, the fusion strength between
PLA foam beads is not high enough during steam forming.
The resulting EPLA incubators are, therefore, not firm
and good-shaped compared to those made of EPS or EPP.
Meanwhile, both material cost of PLA and manufacturing
cost of bead and steam forming are fairly high, which leads
to slow commercialization of EPLA products.
Guangzhou Bio-plus Materials Technology, has been
committed to the development of PLA foaming materials and
applications for many years. Their modified PLA material
for foaming has been industrialized and successfully used
in many applications such as food boxes, trays, coffee
cups, and other products. One of their recent application
innovations is to make biodegradable and biobased
foldable incubators: first continuously extruded PLA foam
sheet is laminated to corrugated cardboard or kraft paper,
to form an insulation board (as shown in Figure 1). Then
foldable incubators are produced using the traditional
manufacturing process for corrugated cartons.
This innovative PLA-foam incubator has many advantages
compared to other incubating materials. Similar to
traditional cartons, the composite insulation board can
be simply folded into an incubator, which is convenient for
operators to fold. It can also save the operating space for
on-site packing as well. This similarity to carton makes
storage and transportation also incredibly easy.
The 40 cm x 40 cm x 40 cm incubator can hold goods over
15 kg and bear weight of 200 kg on its top.
It is made from 4 mm thick PLA foam sheet with an
expansion rate of 15 times; Kraft paper of 300 g/m²; and is
laminated with water-based starch glue. The expansion rate
of PLA foam can be 5-30 times, with thicknesses of 1-6 mm,
and the scraps during PLA sheet production can be
recycled, so the cost of PLA foam sheet is well controllable.
For example, the cost of an above-mentioned PLA-foam
incubator is about three USD.
The material has better insulation properties than
traditional plastics. A comparison of cold insulation and
hot insulation between the foldable insulation incubators of
PLA foam and the traditional EPS over 12 hours is shown
in Figures 2 and 3. Both the outer materials, corrugated
paper and kraft paper, as well as the PLA foam are either
recyclable or compostable. If white cardboard is used as
the outer material of the incubator, exquisite printing can
be realized so that it can be applied to high-end thermal
insulation packaging, such as outer packaging boxes for ice
cream and fresh meat.
Fully automatic production equipment can be used from
foam sheet extrusion to board assembly. In terms of the
extrusion foaming machine of 130/150 screw, 250 kg of
foam sheet can be produced in one hour, which can be
converted into foam sheet that is one meter wide, 5 mm
thick at an expansion rate of 10 times, and 400 meters long.
This would be around 300 incubators in the size of 40 cm x
40 cm x 40 cm.
PLA-foam foldable incubators are currently being tested
by some e-commerce and cold chain transportation
companies in China. Bio-plus is further improving the
physical properties of the incubator by collecting more trial
data. They believe that in the near future, foldable PLA foam
incubators will receive more attention and applications from
enterprises of many industries. They are keen to provide
cold chain transportation companies and suppliers of fresh
products with this eco-friendly, low-carbon, economic
incubator solution, to make this industry more sustainable.
Http://www.bio-plus.cn
Figure 1: Manufacturing process of foldable incubators with PLA foam sheet
Extrusion of PLA foam sheet Lamination of multilayer Folding and printing of board Making an incubator
24 bioplastics MAGAZINE [01/21] Vol. 16