Medical Design Briefs - January 2024 - 28

Design Briefs
Fig. 2 - Carbon footprint reduction potential with thermoplastic resin formulated using renewable feedstock.
sensitive electronics, laser welding reduces
stress on medical devices while
delivering high precision. New LNP ELCRES
CRX copolymer resins and ULTEM™
resins provide optical properties
(i.e., excellent near-infrared (IR) transmission)
required for laser welding.
Still another design strategy to enhance
sustainability is to choose mono-materials
that make recycling easier,
as compared to multi-material
constructs
that may prevent
device
recycling. Converting to mono-materials
offers the potential for easier waste
separation to yield more-consistent recycling
streams. Furthermore, a laser
welded mono-material may be recovered
more easily compared to adhesively
bonded materials, which use glues
that are hard to separate.
A mono-material approach can be
facilitated by selecting several products
from the same polymer family. A
broad portfolio with multiple grades
within a similar base resin allows designers
to find the right product for
each part's specific requirements while
remaining within the same resin chemistry.
One example is combining an
opaque grade of LNP CRX copolymer
with a transparent grade to produce
the housing and lens, respectively, for
a wireless connected device (see Figure
1). In addition, mono-materials
may allow supply chain simplification
by combining similar resins from one
supplier, compared to disparate resins
from multiple suppliers.
28
Replacing Fossil-Based with Certified
Renewable Materials
The growing array of bio-based thermoplastics
can enable device makers to
lower the carbon footprint of their products
significantly - without compromising
quality and performance. Bio-based
versions of thermoplastics that are formulated
with renewable feedstocks certified
under International Sustainability &
Carbon Certification (ISCC) PLUS can
lower carbon footprint while providing
properties identical to those of fossilbased
grades.
For instance, a certified renewable
grade of LNP ELCRIN CRX copolymer
resin can reduce carbon emissions by
more than 40 percent compared to its
fossil-based equivalent in accordance
with ISO 14040/14044 protocols (see
Figure 2). Another example is the certified
renewable ULTEM resin platform,
whose products are certified under ISCC
PLUS and are well suited to healthcare
applications such as surgical devices and
sterilization trays.
Replacing an existing material with a
bio-based equivalent should avoid triggering
full or partial requalification requirements
for regulatory compliance,
which can be costly and time-consuming.
Suppliers can assist by providing
third-party material certification. For
example, for flame retardant resins that
require Underwriters Laboratory (UL)
certification, the UL Solutions Yellow
Card for an existing virgin material can
be extended to its mass-balanced, renewwww.medicaldesignbriefs.com
able
feedstock version without
any additional evaluation. UL
recognizes a renewable grade
as chemically equivalent to the
same grade produced with fossil-fuel
based feedstock. Once
UL acknowledges the chemical
equivalency, the name of
the renewable grade can be
added to the Yellow Card of
the virgin grade as an alternate
designation, or the renewable
material can be recognized in
a separate Yellow Card with
the same UL ratings as the virgin
grade.
ULTEM HU1004 resin for
medical devices is inherently
flame retardant and meets the
UL94 V0 standard at 0.75 mm.
Because this product requires
no FR additives, such as those
based on fluorine technology, it can
help customers comply with pending
regulations on per- and polyfluoroalkyl
substances (PFAS).
Extending the Service Life of
Devices
While many sustainability
initiatives
involving plastics focus on recycling, lowering
energy usage, and avoiding problematic
chemicals, they may overlook
the importance of durability. Extending
the useful life of a plastic product like a
medical device has multiple sustainability
benefits. Longer service life means
less-frequent replacement, which in turn
reduces the consumption of raw materials,
energy for manufacturing, and fuel
for transport. Longer service life also
delays eventual disposal in a landfill or
other waste facility.
Thermoplastics can help extend a device's
service life by resisting degradation
from disinfecting chemicals, UV light and
sterilization, protecting against damage
from harsh working environments, and retaining
aesthetic properties such as color
and surface finish.
Aggressive healthcare disinfectants
present a huge challenge to parts such
as equipment housings that are made
with traditional thermoplastics. Frequent
cleaning can embrittle the material, leading
to environmental stress cracking and
eventual part failure. In comparison, advanced
thermoplastics such as SABIC's
LNP CRX copolymers deliver exceptional
resistance to alcohols, peroxides, and
Medical Design Briefs, January 2024

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Medical Design Briefs - January 2024

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