Significato e scopo

5.1 Man mano che aumenta la resistenza al pennello della vernice, any natural tendency of the painter to overapply the paint will decrease. When all other factors are held constant, increasing brush resistance will result in greater film thickness, resulting in improved durability and concealment. Anzi, it may sometimes be preferred to use a lesser degree of brush drag for easier application (cioè., using a lesser degree of brush drag reduces the time and effort required to apply paint to a particular area).

5.2 This test method provides a standardized spawning procedure for assessing brush resistance as an alternative to the customary informal temporary procedure. The goal is to increase the reliability and precision of determining this feature as much as possible.

Nota 1: Brush drag of paint is directly related to its high shear viscosity. There is generally good ranking order agreement between the results obtained by this method and the test method D4287. The sensitivity of this brushout method has been found to be sufficient to distinguish brush rates corresponding to high shear viscosity differences of not less than 0.3 poise (0.03 Pa.s). The cyclic data show that the ranking order agreement between the brush and viscosity methods is poor when latex and solve-based coatings belong to the same comparison group. This is due to the fact that the two paint types have significantly different rheological properties that can affect the relative perception of brush resistance. four

ASTM D4958-2016 “Confronto della pennellabilità della vernice al lattice”

Ambito di applicazione

1.1 This test method is a standardized brushing procedure for comparing brush resistance of architectural solvent-based coatings.

1.2 With slight modifications, this test method is also applicable to solvent-based coatings.

1.3 I valori espressi in unità SI sono considerati standard. I valori indicati tra parentesi sono solo di riferimento.

1.4 Questo standard non è destinato ad affrontare tutti i problemi di sicurezza, se presente, legati al suo utilizzo. È responsabilità degli utenti di questo standard stabilire adeguate pratiche di sicurezza e salute e determinare l'applicabilità delle restrizioni normative prima dell'uso.