The theory of pigment coloring in powder coatings

polyester powder coatings are thermoset powder coatings consisting of polyester resins, curing agents, pigments, fillers and additivesIn thermoset powder coating, polyester powder coating is one of the main varieties of weather-resistant powder coating, in order to distinguish it from polyester epoxy powder coating, is commonly called pure polyester powder coatingpolyester powder coating strains are also more, the main varieties include the tantalum polyester resin with isocyanic acid triamcinolone triglyceride (TGIC) curing system; Hydroxy polyester resin with closed-type polyhenocyanate curing system, classified as polyurethane powder coating in Chinain polyester powder coating formulation, for polyester resin selection, according to the user's coating appearance and performance requirements, for high gloss, high-performance powder coating, the general choice of polyester resin acid value in 28 to 35 mg KOH/g, glass temperature in more than 60 degrees C of argon-based polyester resin; Resin selection acid value of about 20mgKOH/g, another acid value of about 50mgKOH/g of argon-based polyester resin;on the basis of the choice of polyester resin, the choice of the corresponding curing agent varieties and determine the dosageIn weather-resistant polyester powder coatings, the main curing agents currently used are TGIC and HAAGenerally speaking, TGIC cured polyester powder coating coating appearance, coating film performance is better, the disadvantage is a little higher baking temperature, a little more toxic than HAA, HAA cured polyester powder coating is the disadvantage of coating too thick when the pig pore phenomenon, in the baking curing film yellowing resistance is not as good as the TGIC systemchoose a more suitable curing system according to user requirements, the amount of curing agent can refer to the recommended dosage of the production plant, can also be calculated theoretically:100g polyester resin needt tGIC wtGIC /APE /ETGIC x 561)100g polyester resin required haHA (hydroxylhydrotyamide) WHAA - APE x HHAA/561in the HAA system, rest incense should be appropriately less, leveling agent should be selected to weather good polyester or compounds as a carrier, the brightener on the appearance of the coating film has little impact, but to improve the dispersal of facial fillers and reduce the abuse of film malpractice has certain benefitsThe difference between the results oftheory calculation and the actual test results is inevitable, and the final formula must be determined on the basis of theory and then combined with practicepolyester powder coatings are thermoset powder coatings consisting of polyester resins, curing agents, pigments, fillers and additivesIn thermoset powder coating, polyester powder coating is one of the main varieties of weather-resistant powder coating, in order to distinguish it from polyester epoxy powder coating, is commonly called pure polyester powder coatingpolyester powder coating strains are also more, the main varieties include the tantalum polyester resin with isocyanic acid triamcinolone triglyceride (TGIC) curing system; Hydroxy polyester resin with closed-type polyhenocyanate curing system, classified as polyurethane powder coating in Chinain polyester powder coating formulation, for polyester resin selection, according to the user's coating appearance and performance requirements, for high gloss, high-performance powder coating, the general choice of polyester resin acid value in 28 to 35 mg KOH/g, glass temperature in more than 60 degrees C of argon-based polyester resin; Resin selection acid value of about 20mgKOH/g, another acid value of about 50mgKOH/g of argon-based polyester resin; on the basis of the choice of polyester resin, the choice of the corresponding curing agent varieties and determine the dosage In weather-resistant polyester powder coatings, the main curing agents currently used are TGIC and HAA Generally speaking, TGIC cured polyester powder coating coating appearance, coating film performance is better, the disadvantage is a little higher baking temperature, a little more toxic than HAA, HAA cured polyester powder coating is the disadvantage of coating too thick when the pig pore phenomenon, in the baking curing film yellowing resistance is not as good as the TGIC system choose a more suitable curing system according to user requirements, the amount of curing agent can refer to the recommended dosage of the production plant, can also be calculated theoretically: 100g polyester resin needt tGIC wtGIC /APE /ETGIC x 561) 100g polyester resin required haHA (hydroxylhydrotyamide) WHAA - APE x HHAA/561 in the HAA system, rest incense should be appropriately less, leveling agent should be selected to weather good polyester or compounds as a carrier, the brightener on the appearance of the coating film has little impact, but to improve the dispersal of facial fillers and reduce the abuse of film malpractice has certain benefits The difference between the results of theory calculation and the actual test results is inevitable, and the final formula must be determined on the basis of theory and then combined with practice powder coating is not liquid, but a powder coating, powder coating manufacturing is completely different from traditional solvent-based coatings or water-based coatings, production processes and equipment to some extent similar to plastic processing, in the application does not require solvent participation Therefore, compared with traditional coatings, pigments also have different requirements easy dispersion is an important requirement for pigments in powder coatings, the dispersion of pigments in powder coatings, whether technically or in the state of dispersed materials and liquid coatings, there is no comparability at all Pre-dispersed materials in the melting mixing equipment for a short time, pigment wetting is very difficult, so the dispersal of pigments become particularly important pigments that generally show good dispersion ability in polyolefin plastic particles are more in line with the requirements of powder coatings The heat resistance of powder coatings to pigments is mainly based on the following two considerations, on the one hand, pigments must be able to withstand at least 210 degrees C, lasting about 12 to 15 minutes of coating heating melting leveling drying process, on the other hand, in some end-consumer product surfaces (barbecue racks, stoves, etc.) powder coatings also have to withstand very high temperatures The powder coating rhecity system requires that pigments do not impair the flow properties of the molten coating Only by ensuring good fluidity under low shear force can the dense, smooth and continuous coating formed by the process of heating the melting leveling after coating be heated powder coating sits in a range of 40 to 70 microns, only the paint has excellent covering properties to ensure that the powder coating is close to perfect appearance In the field of outdoor decorative coating, powder coating must go through at least one year of Florida exposure experiments, coating film to maintain good color stability and preservation This has put high demands on the pigment's light resistance and weather resistance The chemical resistance requirements of powder coatings are mainly based on its use, such as powder coatings coated in the washing machine housing must be alkaline-resistant pigments suitable for powder coatings are in the following categories: metallic oxide mixed-phase pigments (composite inorganic pigments) pigment yellow 53 brown 24 blue 28 blue 36 and jaundice (pigment yellow 184) Pigments yellow 34 and red 104 in lead pigments As well as organic synthetic pigment pigment yellow 110; pigment red 112202254255 and 264; pigment purple 19 and 23; pigment blue 60 and 15:1 Currently, surface-treated pigment preparations (e.g wrapped in pyridine resins) have also entered the field of powder coatings