InnoCentive Challenge Name: Stretchable Eco-friendly Material
Doc. Number: (internal use only)
My Solution:
Introduction and Background
There are a number of polymer materials that claim to be "renewable, biodegradable, compostable". For example, Dupont Sorona (technically poly-trimethylene terepthlate or PTT) can be thermoplastic moulding resin or film, and Dupont Cerenol (technically poly-trimethylene ether diol or PED) can be used as a soft segment ingredient in thermoplastic elastomers or polyurethane coating dispersions.
However, Dupont Sorona (PTT) is not biodegradable but recyclable, and Dupont Cerenol (PED) is not readily biodegradable in 28 days.
Detailed Description of the Solution
The Solver's proposed rigid, stretchable, and eco-friendly material is the "Co-Poly-Lactic Acid (Co-PLA)".
Poly-Lactic Acid (PLA), also called Polylactide, is a form of polyester which is thermoplastic and aliphatic. Poly-Lactic Acid (PLA) is a biodegradable and bioresorbable polymer derived from renewable resources like corn starch feedstock, sugar beets, wheat and other starch-rich products. Poly-Lactic Acid (PLA) exhibits many properties that are equivalent to many petroleum-based plastics for a variety of applications, e.g., Cargo Cosmetics's lipstick tube. Poly-Lactic Acid (PLA) is a non-volatile, odourless polymer, and is classified as GRAS (generally recognised as safe) by the Food and Drug Administration (FDA).
Poly-Lactic Acid (PLA) is produced by bacterial fermentation to produce lactic acid, which is oligomerised and then catalytically dimerised to make the monomer for ring-opening polymerisation. Poly-Lactic Acid (PLA) is chiral in nature, i.e., several distinct forms exist as follows.
Poly-D-Lactic Acid (PDLA) is mostly crystalline
Poly-L-Lactic Acid (PLLA) is mostly crystalline
Poly-DL-Lactic Acid (PDLLA) is mostly amorphous
Poly-Lactic Acid (PLA) can be processed into fibre and film. Poly-Lactic Acid (PLA) is sufficiently rigid, reasonably stretchable, and stable under normal use conditions. Poly-Lactic Acid (PLA) is also processable by water casting method, i.e., dispersing the polymeric material in an aqueous solution to form a dispersion, forming the resulting polymeric dispersion into a coating on a suitable substrate, and drying the coating at room temperature.
The Solver's proposed Co-Poly-Lactic Acid (Co-PLA) is a co-polymer or diblock formation in reactive blending of starch and PLA, depending on the particular application of the Seeker. Co-Poly-Lactic Acid (Co-PLA) can have different mechanical properties suitable for specific manufacturing processes, e.g., injection moulding, sheet extrusion, blow moulding, thermoforming, film forming and fibre spinning using conventional techniques and equipment.
Each of the Seeker's Technical Requirements is addressed as follows.
Co-Poly-Lactic Acid (Co-PLA) can be made into a form that is dispersible in water at high concentration to form a highly concentrated dispersion suitable for water casting to form thin film or coating on the Latex sheet substrate.
After drying at room temperature, the thin film or coating of Co-Poly-Lactic Acid (Co-PLA) will exhibit:
Tensile properties in accordance with DIN EN ISO 527-1/3 or ASTM D 882 test for Tensile Modulus (E') and Tensile strain/elongation at break.
Minimum (< 10 %) loss in tensile strength after exposure to 70 % relative humidity at 40 C for 24 hours, water at 40 C for 12 hours, oleic acid, squalane at 40 C for 24 hours, etc.
Readily biodegradable in 28 days and meet the "ultimate biodegradability" following OECD 301 guidelines.
Co-Poly-Lactic Acid (Co-PLA) is made by a synthetic scheme that:
Follows the principles of green chemistry.
Is scalable to large (multi-tons) production scale.
Costs < $100 USD/kg for the proposed coating material.
Raw materials to make Co-Poly-Lactic Acid (Co-PLA):
Is plant-based.
Is non-animal origin.
Is not carcinogen, mutagen, repro-toxic or sensitiser.
Is safe and aesthetically acceptable for application to human skin.
Any offered ingredients or generated by-products are not, according to the Dangerous Preparation Directive (1999/45/EC), classified as R50/53, R51/53, R50, R52, R42 or R43.
References and Notes
There is no patent art preventing the use of specific material for their commercial application.
Examples of Poly-Lactic Acid (PLA) Resins include the following:
Jamplast's Jamplast
Mitsui Chemicals's LACEA
NatureWorks's NatureWorks
Conclusion
The Solver believes that Co-Poly-Lactic Acid (Co-PLA) will meet all of the Seeker's Technical Requirements and Desirable Properties.
