Akzo Nobel Coatings International B.v.

International Coatings Limited

Michele Falcone

Kevin Jeffrey Kittle

Virginie Marcelle Andrée Hancill

Ergin Basar

Robert Edward Barker

Andrew George Cordiner

John Ring

The invention comprises a thermosetting powder coating composition comprising first and second resin, the first resin being an acid functional polyester resin with an acid value below 50 mg KOH/g, the second resin being obtainable by reacting hydroxyl functional components and acid functional components, the hydroxyl functional components containing 2 hydroxyl functional groups per molecule and/or at least 3 hydroxyl functional groups per molecule, the acid functional components containing 2 acid functional groups per molecule and/or at least 3 acid functional groups per molecule, wherein more than 90 mol. % of the total of hydroxyl functional components in the second resin originate from neopentyl glycol (NPG), and from 6 to 11 mol % of the total of hydroxyl functional components and acid functional components in the second resin originating from hydroxyl functional components and/or acid functional components having at least 3 functional groups per molecule.

Thermosetting durable powder coating composition

The invention relates to a thermosetting powder coating composition comprising a first resin and a second resin, the first resin being an acid functional polyester resin with an acid value below 50 mg KOH/g, the second resin being obtainable by reacting hydroxyl functional components and acid functional components, the hydroxyl functional components comprising components containing 2 hydroxyl functional groups per molecule and/or components containing at least 3 hydroxyl functional groups per molecule, the acid functional components comprising components containing 2 acid functional groups per molecule and/or components containing at least 3 acid functional groups per molecule, wherein&#x2014;more than 90 mol. % of the total of hydroxyl functional components in the second resin originate from neopentyl glycol (NPG), and&#x2014;from 6 to 11 mol % of the total of hydroxyl functional components and acid functional components in the second resin originating from hydroxyl functional components and/or acid functional components having at least 3 functional groups per molecule.

The present invention pertains to a process for forming a coating on a substrate using a tribo-charging electrostatic fluidized bed process; characterized in that a powder coating is used which has a particle size distribution such that a) d(v,90)&#x2266;42.5 &#x3bc;m, and b) i) the percentage of particles &#x3c;10 &#x3bc;m in size is &#x2266;12% by volume, and/or ii) [d(s,90)&#xf7;d(s,10)]&#x2266;3.5, [d(s,90)&#x2212;7]d(s,90) being greater than 7 &#x3bc;m and d(s,90) and d(s,10) being measured in microns.

Electrostatic fluidised powder bed coating process

An apparatus and process for forming a coating on a substrate, including establishing a fluidised-bed having a fluidising gas and a powder coating composition, immersing the substrate wholly or partly in the fluidised bed, the substrate being either electrically isolated or earthed, providing an electrically conductive electrode, to which a voltage is applied, positioned to influence the extent to which charged particles adhere to a region of the substrate, withdrawing the substrate from the fluidised-bed and forming the adherent particles into a continuous coating over at least part of the substrates. The apparatus is arranged and the process is conducted such that the maximum potential gradient existing in the fluidised bed is below the ionisation potential of the fluidising gas.

Apparatus and process for forming a powder coating on a substrate using a fluidised bed and tribostatic charging of the powder coating composition

A process for forming a coating on a substrate, including the steps of effecting tribostatic charging of a body of powder by establishing a fluidised-bed of the body of powder in a fluidising chamber at least a part of which is conductive, applying a voltage to the conductive part of the fluidising chamber, immersing a substrate which is electrically non-conductive or poorly conductive, either electrically isolated or earthed, wholly or partly in the fluidised bed, withdrawing the substrate from the fluidised-bed and forming adherent particles of the powder into a continuous coating over at least part of the substrate.

Tribostatic fluidised bed powder coating process

A process for forming a coating on a conductive substrate, including the steps of: establishing a fluidised-bed of a powder coating composition, thereby effecting tribostatic charging of the powder coating composition, the fluidised-bed including a fluidising chamber at least a part of which is conductive, applying a voltage to the conductive part of the fluidising chamber, immersing the substrate wholly or partly in the fluidised bed, whereby charged particles of the powder coating composition adhere to the substrate, the substrate being either electrically isolated or earthed, withdrawing the substrate from the fluidised-bed and forming the adherent particles into a continuous coating over at least part of the substrate. The process offers advantages in terms of coating substrate areas which, because of the Faraday cage effect, are inaccessible in conventional electrostatic powder coating processes, and also enables the formation of thinner coatings than are obtainable by conventional fluidised-bed processes.

Growing community of inventors

Como, Italy

Michele Falcone