Orange Peel & DOI
wave-scan
Product InfoOrange Peel Control of Powder Coated Parts
Optimization of Flow & Levelling Properties
Patchwork might be good for quilts but certainly not for coated industrial goods. As many finished products consist of multiple components which are manufactured by different suppliers and at different locations, uniformity of color and appearance is crucial. Not only the paint batches need to be delivered with consistent quality, but also the production process of the finished product needs to be controlled.
According to Wikipedia the oldest transmitted paint formulation dates back to the 12th century. Since then a lot has changed. Industrial coatings with lower solvent content were introduced resulting in water based systems with almost no solvent. Increasing environmental demands during the last years and requirements for low VOC (volatile organic compounds) systems open the doors for powder coatings with 100 % solids content. Independent of the material, the optical properties of industrial coatings need to fulfill certain quality aspects before they can be applied on the final product.
Optimierung von Verlaufseigenschaften
Nicht nur Farbe beeinflusst das Erscheinungsbild einer lackierten Oberfläche, sondern auch Glanz und der Verlauf. Vorallem „Hingucker-Farben“ sollten wie ein Spiegel glänzen – hochglänzend und absolut glatt. Pulverlacke sind Lacke mit einer hohen Lebensdauer und Beständigkeit. Wie sich aus dem Namen schon ableiten lässt, handelt es sich um pulverförmige Lacke ohne Lösungsmittel. Vor dem Aushärtungsprozess unter hohen Temperaturen werden sie typischerweise elektrostatisch aufgetragen.
Kennzeichnend für Pulverlacke ist eine wellige Appearance. Für ein ansprechend glattes Aussehen werden Verlaufsadditive eingesetzt, um Oberflächenspannungen auszugleichen, wodurch Krater vermieden und der Verlauf (Orange Peel) verbessert wird. Diese Additive bestehen häufig aus Polyacrylaten und sind nur in kleinen Mengen für Rezepturen notwendig.
The graphs show how the additive BYK-3902 P clearly decreases LW and SW values in a polyester/ epoxy powder coating system. BYK-3902 P is particularly suitable for thin-layer powder coatings that are used to reduce costs or for applications like racing bikes where the final product is weight sensitive. Therefore, compared to a standard flow & levelling additive the improvement is especially noticeable at lower film thickness of 30 – 45 μm.
Measurements were taken with the wave-scan instrument which is rolled across the surface to scan the wavy light /dark pattern. The data of the optical profile is divided into different wavelength ranges (0.1 mm to 30 mm) by using mathematical filter functions. Commonly used are SW-data (0.3 – 1.2 mm) and LW-data (1.2 – 12mm) to describe flow levelling behavior. For small and curved parts the micro-wave-scan is beneficial.
Other ALTANA divisions
A member of
