Method for recycling a used polyamide composition

EP4598990A1Pending Publication Date: 2025-08-13ARKEMA FRANCE SA
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Patent Information

Application Number
EP2023793924
Authority / Receiving Office
EP · EP
Patent Type
Applications
Current Assignee / Owner
Priority Date
2022-10-05
Filing Date
2023-10-05
Publication Date
2025-08-13

AI Technical Summary

Technical Problem

Current recycling processes for polyamide compositions from 3D printing waste are inefficient, often requiring aggressive acidic conditions and failing to control the thermal characteristics and purity of the recycled polyamide powder, leading to reduced quality in 3D printing applications due to close melting and crystallization temperatures.

Method used

A dissolution/precipitation process that involves heating a used polyamide composition in a solvent, cooling it to a precipitation temperature, and maintaining the temperature to convert a polyamide powder with multiple melting temperatures into one with a monomodal melting endotherm, thereby increasing the gap between melting and crystallization temperatures, allowing for improved thermal characteristics and separation of polyamide from other compounds.

Benefits of technology

This process results in a polyamide powder with a wider working window, improved geometric precision, and increased purity, enhancing the quality and definition of 3D printed objects while being easier to implement and not requiring acidic conditions.

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Abstract

The invention relates to a method for recycling a used polyamide composition to form a recycled polyamide powder that has a unimodal melting endotherm and a single melting point (Tf1max), the method comprising the steps of: i.e. bringing a used polyamide composition into contact with a solvent in order to obtain a mixture; ii. heating the mixture to solubilise the polyamide in the solvent; iii. cooling the mixture to the precipitation temperature (Tp) of the polyamide in the solvent, whereby a precipitated polyamide powder characterised by a non-unimodal melting endotherm and more than one melting point is obtained, (Tf1max) being the highest melting point; and maintaining the temperature of the mixture at a temperature at most equal to Tp, in particular within the range from Tp -0.1°C to Tp -15°C, until the precipitated polyamide powder is characterised by a unimodal melting endotherm and one melting point (Tf1max); and recovering the obtained recycled polyamide powder.
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