05 | 2008

Bottle Applications
PLA Bottles
the gas barrier performance of EcoSield and EcoSield-
WO compared to a PET bottle. The barrier performance is
only 1/8 (water vapor) and only 1/9 (oxygen) of that of PET.
The EcoSield-WO however, has a slightly improved water
vapor barrier performance over the PET bottle. Compared
to existing PLA bottles an excellent gas barrier advantage
for both water vapor and oxygen can be seen. With these
barrier enhancements EcoSield-WO is suitable for oxygen
and water vapor sensitive contents, just as a PET bottle.
Figure 3 shows the storage temperature dependency on
the water vapor barrier performance of EcoSield, EcoSield-
WO and the PET bottle. As can be seen, EcoSield-WO has
the same water vapor barrier performance as the PET
bottle at temperatures of up to 45°C. Thus, EcoSield-WO
will be suitable for water vapor sensitive contents similar
to a PET bottle.
With regard to biodegradability, Toyo Seikan is looking
at two points, namely reduction of plastic waste and
ease of disposal for each household to achieve a positive
contribution to society. EcoSield is biodegradable under
certain circumstances. Figure 4 shows the degradation
results in an electrically powered house-hold-composter 1 ,
as it is used in Japanese households. As the picture shows
EcoSield can be broken down within 32 hours in such a
‘home-composting unit’ 1 . In addition, the biodegradability
was determined by measuring the carbon dioxide generated
(ISO 14855 part 2) by the reaction with microorganisms
using standard compost and EcoSield at 58°C. EcoSield
can be biodegraded within 45 to 50 days, which means
that the biodegradability of EcoSield is rapid in controlled
compost conditions. With regards to these results, the
advantages in disposing of PLA bottles make it possible
to promote a change in the way societies approach waste
collection and processing. If this bottle becomes more
widely used throughout the world the environment would
naturally become cleaner.
Toyo Seikan seriously hopes that the EcoSield technology
will be able to contribute to reducing global warming as
much as possible.
www.toyo-seikan.co.jp/e
Fig. 2:
Thermal
stability
25
Fig. 3:
Gas barrier
property of
water vapor
Table 1:
Gas barrier
performance
Start
End
Over flow volume reduction (%)
Water vapor permeation (g/m 2 day)
20
15
10
5
PLA bottle
Purchased from Market
0
1.0 2.0 3.0 4.0 5.0
d-isomer content (%)
Sample condition: Mold temperature 30 ºC
Storage condition: 55 ºC
Storage period: 7 days
30
25
20
15
10
5
EcoSield TM
(Standard)
EcoSield-WO TM
(High Barrier)
PET
0
0 10 20 30 40 50
Storage temperature (ºC)
EcoSield-WO TM (Under development)
Bottles H 2
O O 2
PET 1.0 1.0
EcoSield TM
(Standard: PLA only)
EcoSield-WO TM
(High Barrier)
1 / 8 x 1 / 9 x
1.3 x 1.0 x
EcoSield-WO TM (Under development)
Barrier performance has been improved
by Toyo Seikan’s unique gas barrier technology.
After 20
treatments
(80Hr)
After 4
treatments
(16Hr)
After 16
treatments
(64Hr)
After 12
treatments
(48Hr)
After 8
treatments
(32Hr)
1: This has nothing in common with what is usually referred to
as “home composting”. In such an electric home-composter,
temperatures of approx. 80°C are applied to reduce the
volume of kitchen waste.
Fig. 4: Degradation by ‘home composting’ 1 process
bioplastics MAGAZINE [05/08] Vol. 3 25