3.1.1 Functional Unit
The functional unit of the LCA study is the production of 1 kg of bio-based plastic
blend, made primarily of biopolymer PLA, to be used to manufacture 25 pieces of
computer mouse bodies, which include right mouse button, left mouse button, palm
rest and the base [9].
3.1.2 System Boundaries
The system boundaries are set from cradle to gate, which includes raw material
acquisition phase, production of the bio-based plastics blends and finally the processing of the blends to manufacture the computer mouse pieces. The use and End
of Life (EoL) phases of the product system are not considered for this study due to
the limited availability of data on the consumer behaviour and the strategies to use
and dispose the products after its use phase. However, some factors influencing
these two phases are included as a part of the eco-design strategy definition, which
will be explained in Sect. 4. This LCA study is done in accordance to ISO 14040
[10] and ISO 14044 [11] and supported by the software GaBi 6 [12]. From Fig. 2, it
can be seen that the raw material acquisition phase includes the manufacture,
processing and the transport of the polymers, additives and other chemicals from
their original sites to Germany, where they will be extruded, granulated, crystallized
and packed as bio-based plastics blends. The main components of the blend are the
biopolymers Poly-L-Lactic Acid (PLLA) and Poly-D-Lactic Acid (PDLA), which
are produced from sugarcane and sugar beets respectively. Both PLLA and PDLA
come under the biopolymer type PLA and is one of the widely used biopolymers
with suitable mechanical properties. The processing phase involves in the
pre-processing of these bio-based plastic blends before bringing it to a specific form
(here, body of the computer mouse) by injection moulding. The finished product is
then sent to an assembly site (electronic parts of mouse are not included in the
system boundaries) and finally distributed to the consumers. The utilities such as
process steam, process water, compressed air and output flows such as emissions
and wastes are considered within each process even though they are not explicitly
shown in Fig. 2.
3.1.3 Life Cycle Inventory Data Sources and Data Quality
Requirements
The bio-based plastic blend, which is used in the manufacture of the body of a
computer mouse, is made of biopolymers and additives. The production of the
bio-based plastic blend takes place in Germany. Inventory data for the manufacture
of PLLA, PDLA and other additives in the raw material acquisition phase were
picked up from different literature sources [13, 14]. The background Life Cycle
Inventory (LCI) datasets were considered for different utilities like process steam,
490
V. Venkatachalam et al.
The functional unit of the LCA study is the production of 1 kg of bio-based plastic
blend, made primarily of biopolymer PLA, to be used to manufacture 25 pieces of
computer mouse bodies, which include right mouse button, left mouse button, palm
rest and the base [9].
3.1.2 System Boundaries
The system boundaries are set from cradle to gate, which includes raw material
acquisition phase, production of the bio-based plastics blends and finally the processing of the blends to manufacture the computer mouse pieces. The use and End
of Life (EoL) phases of the product system are not considered for this study due to
the limited availability of data on the consumer behaviour and the strategies to use
and dispose the products after its use phase. However, some factors influencing
these two phases are included as a part of the eco-design strategy definition, which
will be explained in Sect. 4. This LCA study is done in accordance to ISO 14040
[10] and ISO 14044 [11] and supported by the software GaBi 6 [12]. From Fig. 2, it
can be seen that the raw material acquisition phase includes the manufacture,
processing and the transport of the polymers, additives and other chemicals from
their original sites to Germany, where they will be extruded, granulated, crystallized
and packed as bio-based plastics blends. The main components of the blend are the
biopolymers Poly-L-Lactic Acid (PLLA) and Poly-D-Lactic Acid (PDLA), which
are produced from sugarcane and sugar beets respectively. Both PLLA and PDLA
come under the biopolymer type PLA and is one of the widely used biopolymers
with suitable mechanical properties. The processing phase involves in the
pre-processing of these bio-based plastic blends before bringing it to a specific form
(here, body of the computer mouse) by injection moulding. The finished product is
then sent to an assembly site (electronic parts of mouse are not included in the
system boundaries) and finally distributed to the consumers. The utilities such as
process steam, process water, compressed air and output flows such as emissions
and wastes are considered within each process even though they are not explicitly
shown in Fig. 2.
3.1.3 Life Cycle Inventory Data Sources and Data Quality
Requirements
The bio-based plastic blend, which is used in the manufacture of the body of a
computer mouse, is made of biopolymers and additives. The production of the
bio-based plastic blend takes place in Germany. Inventory data for the manufacture
of PLLA, PDLA and other additives in the raw material acquisition phase were
picked up from different literature sources [13, 14]. The background Life Cycle
Inventory (LCI) datasets were considered for different utilities like process steam,
490
V. Venkatachalam et al.