Method for the Depolymerization of a Poly(alpha-Hydroxy Acid)

Simple SummaryContent extracted from patent full text and abstract with AI.

This invention describes an efficient method for breaking down poly(alpha-hydroxy acid) polymers, such as poly(lactic acid), into their constituent monomers using only water and a zinc-based catalyst (preferably zinc acetate). The process operates at moderate temperatures (≥140 °C, typically 160-200 °C), can utilize end-of-life or waste plastics, and avoids the use of toxic or costly organic solvents. The monomers produced (e.g., lactic acid) can then be used to synthesize new polymers, enabling a true chemical recycling loop for bioplastics.

Use CasesContent extracted from patent full text and abstract with AI.

• Chemical recycling facilities for biodegradable plastics (e.g., PLA waste from packaging, cups, cutlery, 3D printing materials)
• Municipal or industrial waste management plants seeking to recycle bioplastics efficiently
• Manufacturers of poly(lactic acid) interested in closed-loop recycling systems to produce new PLA from recovered monomers
• Recycling mixed or contaminated plastic waste streams containing bioplastics
• Processing bioplastic composites or items with various contaminants (dyes, adhesives, other plastics) that are hard to recycle mechanically

BenefitsContent extracted from patent full text and abstract with AI.

• Enables highly efficient depolymerization of PLA and related bioplastics to monomers with high yield, even from low-quality or contaminated waste
• Uses only water as a reagent and solvent, avoiding hazardous organic solvents and minimizing environmental concerns
• Operates in relatively short reaction times (as little as 10–60 minutes) and moderate temperatures with zinc-catalysts, making the process industrially attractive
• Tolerant to contamination and other polymer types, making it suitable for real-world, unsorted plastic waste streams
• Facilitates closed-loop recycling, regenerating high-quality PLA regardless of the input waste quality
• Reduces reliance on land and agricultural resources for raw bioplastic production by allowing efficient recycling
• Contributes to sustainability and circular economy goals by reducing plastic waste and supporting CO2-neutral materials cycles

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Inventors & Applicants

Patent Abstract

The invention relates to a method for the depolymerization of a poly(α-hydroxy acid), for example a poly(lactic acid). The method comprises the steps of:a) contacting the poly(α-hydroxy acid) with water; andb) heating the mixture of the poly(α-hydroxy acid) and water in the presence of a catalyst suitable for catalyzing the depolymerization of the poly(α-hydroxy acid).