A new polyamide 4 spherical fine particle has been developed by Japan-based Toray Industries, that, says the company, has been demonstrated to biodegrade in the marine environment.
The company will provide samples and evaluate the fine particle as a raw material for cosmetics, to replace conventional, non-biodegradable particles long used in cosmetic products such as foundation and eye shadow. Toray plans to push ahead with technological development for mass production and sales, with commercialisation targeted for the end of March 2025.
Unlike the PA12 fine particles produced by Toray to date, the new PA4 products are subject to biodegradation processes, where bacteria, fungi, and other microorganisms break down organic compounds into simpler inorganic substances, including water and carbon dioxide. Biodegradation is generally slower in the sea, where microorganisms are less abundant than in the soil.
Microplastic particles in cosmetics and facial cleansers pass through domestic wastewater treatment and filtration systems and end up in the seas. This has undermined environmental biodiversity and marine pollution prevention efforts, prompting regulators around the world to begin restricting these materials. In September 2023, the European Chemicals Agency introduced a new restriction on microplastics under an annexe to the REACH regulation. Gradual limitations on the use of intentionally added synthetic polymer particulates smaller than 5 mm will be rolled out, with a total ban starting in 2035.
Biodegradable polyamide 4 offers a means to overcome these environmental and regulatory challenges.
Spherical polymer particles are produced in either of two ways. The first is by dissolving the polymer in a solvent to form spherical micelles, then removing the solvent. The second is by melting the polymer. The problem with the first method is that only few solvents can dissolve polyamide 4. The high melting point and thermal properties that cause thermal decomposition on melting make the second option problematic. Toray said it has overcome these challenges through the use of proprietary technology developed through years of R&D.
