Spherical particles for automotive powder coatings

Satoh, H.; Yutaka, Harada; Libke, Shannon

doi:10.1016/s0300-9440(97)00116-1

Cited by 7 publications

(5 citation statements)

References 6 publications

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“…In the current state of art two types of powders (coarse and ultrafine, as defined by Zhu and Zhang [28], the former larger than 30 μm while the latter smaller than 25 μm in median particle size) are applicable for powder coating. In particular, ultrafine powder is being developed to replace coarse powder in finishing industry, profiting from its potentials to offer better surface appearance and cost saving [27][28][29][30]. Thus, investigations of the particle-size evolution in the deposited layer are essential for gaining a better understanding of powder coating and for elucidating the ultimate film appearance, which were conducted in this study by employing a typical coarse and ultrafine powder.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Characterization of particle size evolution of the deposited layer during electrostatic powder coating processes

2009

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Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Characterization of particle size evolution of the deposited layer during electrostatic powder coating processes

2009

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“…Recently, there has been a strong trend to reduce the particle size to improve the surface quality of the final coatings and lead to the considerable cost savings of material and energy [2][3][4][5][6][7]. Therefore, ultrafine powder coatings (D 50 < 25 µm) have attracted more and more attention from the finishing industries, such as oral drug delivery systems, dental and orthopedic implants and the pharmaceutical industry [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Performances of Al(OH)3 and BaSO4 in Ultrafine Powder Coatings

Franco

Yang

et al. 2019

Processes

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Ultrafine powder coatings are one of the development directions in the powder coating industry, as they can achieve thin coatings with good leveling and high surface smoothness comparable to liquid coatings. Compared to regular coatings, they experience a higher sensitivity to any incompatibilities, e.g., filler from coating components. The properties of fillers play a great role in the performance of coating films. Aluminum trihydrate (Al(OH)3) is a well-known filler in solvent-based coatings and other polymer industries. To study and evaluate the performances of Al(OH)3 in ultrafine powder coatings, a popular filler, barium sulfate (BaSO4) is used for comparison. Both fillers are added in ultrafine powder coatings based on two of the most commonly used resin systems (polyester-epoxy and polyester). The differences of physical and chemical properties between both fillers have significant influences on several properties of powder paints and coating films. The polar groups (hydrogen bond) in Al(OH)3 result in the strong interaction between inorganic filler and organic polymer matrix, thus decreasing the molecular network mobility and influencing the chain formation, which is verified by differential scanning calorimetric (DSC). The bed expansion ratio (BERs) of powder paints incorporated with Al(OH)3 are much higher than those with BaSO4, which indicate more uniform gas-solid contact during the spraying process. Samples with Al(OH)3 exhibit much lower specular gloss at 60°, which are expected to achieve remarkable matting effects. Superior corrosion resistances can be observed for almost all the coated panels incorporated with Al(OH)3 in contrast to those with BaSO4. Other aspects are slightly influenced by the difference between the two fillers, such as the angle of repose values (AORs) of powder paints, the impact resistance and flexibility of coating films.

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“…For instance, all the applications of powder coating in automotive industries are limited to underbody, trim components, steel and aluminium car wheels [39]. However, ultrafine powder was successfully demonstrated in the literature of being capable of improving the film appearance and decreasing the film thickness [36,[39][40][41]. Therefore, ultrafine powder is attracting more and more attention from the finishing industries due to its superior properties and is considered as the next generation of powder coating [8,36,39,42,43].…”

Section: Introductionmentioning

confidence: 99%

The characteristics of particle charging and deposition during powder coating processes with ultrafine powder

Meng¹,

Zhu²,

Zhang³

2009

J. Phys. D: Appl. Phys.

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In a preceding work, the mechanisms of particle charging and deposition during powder coating processes were explored with coarse polyurethane powder. In this paper, the developed mechanisms were further examined with ultrafine polyurethane powder in order to meet the growing needs for ultrafine powder in finishing industries. This study first verified the previous findings in particle deposition, which account for a cone-shaped pattern formed by deposited particles on the substrate and a rise in particle accumulation in the fringe region. It was further demonstrated with ultrafine powder that, as disclosed by using coarse powder, the primary charging of in-flight particles competes with back corona in particle deposition processes, and the highest deposition efficiency is a compromise by balancing their effects. In comparison with coarse powder, ultrafine powder presents a faster reduction in the deposition rate with extended spraying duration, but shows some superiority in the uniformity of the deposited layer. In the case of charging characteristics of the deposited particles, it was further substantiated with ultrafine powder that the secondary charging mechanism takes predominance in determining the distribution of local charge-to-mass ratios. It was also disclosed that ultrafine powder shows a decreasing charge-to-mass ratio with increased charging voltage in the deposited layer, opposite to the increasing tendency of coarse powder. However, it was commonly demonstrated by both coarse and ultrafine powders that the charge-to-mass ratio of the deposited particles decreases with the extended spraying durations. In comparison, ultrafine powder is more likely to produce uniform charge-to-mass ratio distributions in the deposited layer, which contrast sharply with the ones associated with the coarse powder. In conclusion, it is believed that this study supplements the preceding study and is of great help in providing a comprehensive understanding of the mechanisms of corona charging processes of different powders.

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Spherical particles for automotive powder coatings

Cited by 7 publications

References 6 publications

Characterization of particle size evolution of the deposited layer during electrostatic powder coating processes

Characterization of particle size evolution of the deposited layer during electrostatic powder coating processes

Comparative Study of the Performances of Al(OH)3 and BaSO4 in Ultrafine Powder Coatings

The characteristics of particle charging and deposition during powder coating processes with ultrafine powder

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