Method for producing a PET starting material that is suitable for use in an extrusion blow molding method, and hollow article produced in the extrusion blow molding method
AssigneeAlpla Werke Alwin Lehner GmbH & Co. KG
InventorsRobert Siegl, Andreas Weber
Life of this patent
Estimating the term…
Abstract
The invention relates to a method for producing an EBM bottle with 0.90 to 1.5 dL/g from a bottle-grade PET post-consumer recycling flake, i.e., a recycled, post-consumer PET with a viscosity of 0.65 to 0.84 dL/g, using extrusion processes, solid state polycondensation processes, and a blowing process.
Claims20
A method for producing a PET starting material suitable for use in an extrusion blow molding method, for producing a hollow article made of plastic, comprising:
- a) sorting by type, washing and comminuting post-consumer PET articles, wherein the post-consumer PET material has an intrinsic viscosity between 0.65 and 0.84 dL/g,
- b) removing contaminants before, simultaneously to, or after step a),
- c) drying the comminuted PET material,
- d) melting the comminuted PET material, admixing a pyromellitic dianhydride as a chain extender or chain brancher, and extruding reactively the melt of comminuted PET material and chain extender or chain brancher, wherein the admixing of the chain extender or the chain brancher can take place before or during melting, and wherein a temperature during extrusion and a quantity of chain extender or chain brancher are selected such that the reactive extrusion increases the intrinsic viscosity by 0.05 to 0.2 dL/g and the extruded material has an IV greater than 0.75 dL/g,
- e) producing granules from the extruded PET material, and
- f) increasing an intrinsic viscosity of the granules further by a subsequent heat treatment in solid state polycondensation, wherein the solid state polycondensation is carried out at temperatures of ≤225° C. increasing the intrinsic viscosity by a further 0.1 to 0.6 dL/g to above 0.9 dL/g.
A method for producing a PET starting material suitable for use in an extrusion blow molding method, for producing a hollow article made of plastic, comprising:
- a) sorting by type, washing and comminuting post-consumer PET articles, wherein the post-consumer PET material has an intrinsic viscosity between 0.65 and 0.84 dL/g,
- b) removing contaminants before, simultaneously to, or after step a),
- c) drying the comminuted PET material,
- d) melting the comminuted PET material, admixing 0.105 wt % of pyromellitic dianhydride as a chain extender or chain brancher, and extruding reactively the melt of comminuted PET material and chain extender or chain brancher, wherein the admixing of the chain extender or the chain brancher can take place before or during melting, and wherein a temperature during extrusion is selected such that the reactive extrusion increases the intrinsic viscosity by 0.05 to 0.2 dL/g and the extruded material has an intrinsic viscosity between 0.8 and 0.9 dL/g,
- e) producing granules from the extruded PET material, and
- f) increasing an intrinsic viscosity of the granules further by a subsequent heat treatment in solid state polycondensation, wherein the solid state polycondensation is carried out at a temperature of 200° C. increasing the intrinsic viscosity by a further 0.1 to 0.6 dL/g to an intrinsic viscosity above 0.9 dL/g.
Dependencies are inferred from the claim text.