Process for manufacture of powder coating compositions

• Main Authors: BEAL, LUDOVIC, GRAWE, THOMAS, VAN DEN BOSH, GUIDO, RODRIGUEZ-SANTAMARTA, CARLOS, JONES, PIP
• Format: Patent
• Language: English; French; German
• Published: 04.05.2011
• Subjects: ADHESIVES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; FILLING PASTES; INKS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; POLISHES; USE OF MATERIALS THEREFOR; WOODSTAINS

The present invention provides a process for manufacture of a powder coating composition, the process comprising the steps a) providing at ambient temperature or increased temperature and, optionally, under shear conditions at least one solid component selected from the group consisting of at least one binder resin and, optionally at least one curing agent, and optionally, at least one pigment and/or extender and/or coating additive, b) adding of at least one calibrated pigmented liquid, based on at least one pigment, to the mixture of step a) and dry-mixing, wherein the dry-mixing is provided under sub-atmospheric pressure in a range of 1 to 700 mbar, and under speed-controlled shearing with a mixer speed in a range of 100 to 5000 rpm, and at a temperature of the mixture between 15°C and Tg and/or Tm of the solid component(s) suitable not to soften or melt the solid components in the mixture and suitable to evaporate the liquid components of the calibrated pigmented liquid and to avoid building of a paste form of the mixture, and c) processing the resulted dry-mixture to a final powder coating composition. The process of the invention provides a powder coating composition providing precise colour of the coatings having a desired colour with high colour stability. The process of the invention provides a simple and efficient way to produce a pre-product based on the calibrated pigmented liquid wherein the calibrated pigmented liquid is homogeneously distributed over the solid raw material, for further processing to a powder coating composition.