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US 7,740,938 B2Granted
Production of spherical polyamide particles
AssigneeRhodia Polyamide Intermediates
InventorsMatthieu Helft, Eric Roche
Life of this patent
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Abstract
Spherical polyamide particles having a mean particle size of less than 1 mm, notably less than 100 μm, are produced by dispersing the polyamide monomers in an inert liquid and then polymerizing same.
Claims20
A process for preparing spherical polyamide particles having a mean diameter of less than 1mm, comprising the following steps:
- a) preparing a dispersion of a first liquid which comprises a solution of polyamide monomers in a solvent, in a second inert liquid thereby forming a reaction medium, the reaction medium comprising two phases, a continuous phase formed by the second liquid, and a dispersed phase formed by the first liquid, the first and second liquids are essentially immiscible, wherein the ratio between the volume of the first liquid and the volume of the second liquid is greater than or equal to 0.5;
- b) polymerizing the monomers by polycondensation and/or polyaddition by heating the reaction medium and maintaining the heating at a temperature below the melting point of the polyamide with the desired degree of polymerization;
- c) optionally, decompressing the reaction medium to atmospheric pressure;
- d) optionally, gradually cooling the reaction medium;
- and
- e) recovering the spherical polyamide particles therefrom.
3 more elements
Dependencies are inferred from the claim text.