Method for Producing a Population of Particles of Polyethylene Terephthalate or Polybutylene Terephthalate or of a Copolymer Comprising Pet And/or Pbt

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

This invention is a method for producing uniform, spherical particles made from polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or their copolymers. The process involves dissolving the polymer in a specifically chosen organic solvent at elevated temperatures (above 100°C), then carefully cooling the solution to precipitate the polymer out as particles of well-controlled size (5 to 200 µm) and shape. The method provides a high yield of particles with narrow size distribution and high sphericity without the need for further sorting.

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

• Production of polymer powders for selective laser sintering (SLS) and selective laser melting (SLM) in additive manufacturing (3D printing).
• Manufacturing of finely controlled polymer powders for powder bed fusion processes.
• Upcycling of PET beverage bottles into high-quality powders for industrial applications.
• Preparation of specialty polymer powders for use in laser beam melting or other advanced powder processing techniques.
• Creation of pigment or additive-containing polymer powders for tailored properties such as improved flow, antistatic behavior, or flame retardancy.

BenefitsContent extracted from patent full text and abstract with AI.

• Produces highly spherical particles with a very narrow size distribution, improving flowability and packing density of powders.
• Reduces or eliminates the need for post-production sorting or sieving of particles, saving time and costs.
• Allows for inclusion of additives for flow, pigmentation, stabilization, or special functionality during particle formation.
• Suitable for direct use in powder-based additive manufacturing, leading to better quality finished parts with higher precision.
• Has superior control over residual solvent content—especially when using cyclopentanone—resulting in better quality and dimensional stability of parts produced by laser sintering/melting.
• Enables recycling and upcycling of waste materials, such as PET bottles, into valuable polymer powders.
• The process can be tuned to adjust particle sizes and distributions as required by specific applications.

Technical Classifications (CPCs)

Inventors & Applicants

Patent Abstract

The invention concerns a method for producing a population of particles of a polymer, which particles have particle sizes in the range of 5 µm to 200 µm, wherein the polymer is polyethylene terephthalate (= PET) or polybutylene terephthalate (= PBT) or a copolymer comprising PET and/or PBT, wherein the polymer is dissolved in an organic solvent which solvent is selected such that it completely solubilizes the polymer only at a temperature of the solvent above 100 °C, wherein the method comprises heating of the solvent and the solid polymer immersed in the solvent at least to a first temperature, at which first temperature the polymer is completely dissolved, cooling the solution, wherein the cooling is practiced until a second temperature is reached at which second temperature clouding of the solution starts, further cooling the solution at a rate in a range of 0.05 °C/min to 5 °C/min or keeping the solution at the second temperature or at a temperature up to 3 °C below the second temperature for at least 5 min and then cooling the solution at a rate in a range of 0.05 °C/min to 5 °C/min, wherein cooling occurs at least until a third temperature is reached at which turbidity does not further increase, and separating the particles formed during step b) or c) from the solution.