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Dirk Eierhoff

BASF Coatings

Characterization of Paint Atomization and Inline Appearance Measurements – Tools for a Deeper Understanding of Application Processes and Resulting Film Properties

Abstract

Within the automotive coating industry, an entire understanding of the processes from atomization of sprayable paints via film formation, flash-off/drying and curing through to the final film properties in terms of levelling, pinhole/popping, mottling etc. as well as correlations with the coating formulation and process parameters still remains a major challenge. However, fundamental knowledge about how these processes can be purposefully influenced by an adaption of the formulation or change in process parameters and how thereby an optimized overall performance can be achieved might help to effectively accelerate the development of coatings as well as the introduction of new products at the OEM paintshop. At the department “Application & Process Technology” of BASF Coatings, this challenge has been addressed by establishing a broad project landscape covering topics such as characterization of the atomization (e.g., measuring the droplet size/velocity distribution) impact of wet film formation on appearance identification of key factors for improved transfer efficiency influence of the rheological properties of a coating on atomization identification of root causes for atomizer pollution and corresponding cleaning strategies mechanisms of the appearance and sagging progression in the course of the drying/baking process automatization (e.g., development of a sanding and polishing robot system for reproducible simulation of repair processes) development and implementation of novel and innovative methodologies to foster an enhanced elementary comprehension.

An overview of the activities at BASF Coatings’ department “Application & Process Technology” and recent achievements will be shared. Particularly, the presentation will focus on two topics: The impact of material characteristics such as rheological behavior or type of pigmentation on atomization and resulting film properties will be discussed; the underlying characterization of the spray was conducted via SpraySpy® (based on the time shift method) which enables a differentiation between optically different particles. Furthermore, a proprietary measurement procedure based on deflectometry for an automated levelling and sagging analysis during drying will be presented; examples for the impact of clear coat formulation modifications on the temporal progression of surface waviness (long and short wave) during heating up as well as during cooling down of the substrate will be shown.

Biography

Biography coming soon.