Issue 04/2016

Blow Moulding
By:
Pilar Diego, Chelo Escrig
Extrusion Department
AIMPLAS (Plastics Technology Center)
Valencia, Spain
Partners
Seven companies and technological centers have
worked with AIMPLAS, who has coordinated this project;
VLB (Germany), OWS (Belgium), CNR (Italy), VIZELPAS,
ESPAÇOPLAS (Portugal) and ALMUPLAS, ALJUAN (Spain).
About AIMPLAS
AIMPLAS is a Plastics Technology Center located in
Valencia, Spain. It is a non-profit research association
which has the objective of acting as a technological
partner with companies in all sectors related to plastics,
customizing integral and personalized solutions through
the coordination of R&D&I projects and technological
services.
Mode of operation
The 2-year project was finished in May 2016. The first
period of the project was mainly focused on the studies at
lab and pilot plant scale while the second period mostly
concentrated on the industrial scale-up, product validation
and environmental and economic studies, i. e.:
• Definition of requirements, material selection based on
the biodegradable materials and additives and study of
chemical modifications
• Evaluation of bio-compounds’ processability at pilot
plant level considering the different manufacturing
processes: Blown film extrusion and form-sealing
packaging machine to obtain pouches, extrusion blow
moulding for bottles and injection moulding for caps.
• The scaling-up industrial processes according to
the optimized parameters at pilot plant level and the
optimization state to achieve the desired output (see
figures)
• Full characterization and validation of the final industrial
products to be used in the dairy applications defined
Table 1: Requirements of the packages for dairy products
Package Flexible pouches Small bottle Big bottles and caps
Type of contained
product
Fresh milk
Probiotic yogurt
products
Fresh milk and shakes
Shelf-life 4 – 7 days at < 8 °C 2 – 3 weeks at < 8 °C 2 – 3 weeks at < 8 °C
Thermal treatment
Technology
Pasteurization
72 – 75 °C, 15 – 40 s
Blown film coextrusion
Pasteurization
72 – 75 °C, 15 – 40 s
Extrusion blow
moulding
Sterilization (bottle)
90 – 95 °C, 4 – 20 s
Extrusion blow moulding
and injection moulding
Package structure Multilayer (3 layers) Monolayer Monolayer
Additional
requirements
Withstand horizontal
form sealing machine
Lid sealing
Lid sealing and caps
Barrier properties Not applicable Not applicable Not applicable
Table 2: Thermal and mechanical properties in pouches
(MD=Machine Direction, TD= Transverse Direction)
Standard Formulation Reference LDPE Bio 03-04
EN ISO
527-2:
2012
EN ISO
14477:
2004
Direction MD TD MD TD
Stress at yield (MPa) 1.7 ± 0.1 1.4 ± 0.2 1.8 ± 0.2 1.1 ± 0.1
Elongation at yield (%) 16 ± 1 9 ± 0.9 32 ± 9 12 ± 1
Stress at break (MPa) 2.3 ± 0.2 2.1 ± 0.4 3.8 ± 1 2.6 ± 0.1
Elongation at break (%) 710 ± 120 1200 ± 150 620 ± 89 660 ± 35
Maximum Stress (MPa) 2.79 ± 0.16 4.67 ± 0.14 2.79 ± 0.16 4.67 ± 0.14
Penetration (mm) 1.6 ± 0.1 1.80 ± 0.04 1.6 ± 0.1 1.80 ± 0.04
Energy (mJ) 2.54 ± 0.17 4.72 ± 0.25 2.54 ± 0.17 4.72 ± 0.25
Thickness
(microns)
120 100
EN ISO 306 Vicat Temperature (ºC) 100 – 115 92 – 95
bioplastics MAGAZINE [04/16] Vol. 11 13