Physical parameters of closed type acid catalyst N-2500

Type: p-TSA isopropanol
PH value: 6.0-7.0
Appearance: dark brown solution
Active ingredient: 26%-35%
Pound/gallon: 8.15
Sealing temperature: 80℃

During construction, the first step is to dip the paint. Experience has shown that in the dipping process with a shear rate of about 15-30 s-l, when the viscosity is higher than 2.5 Pa·s, it has good brush transfer performance. When applied at high shear rate, the viscosity can reach 0.1~0.2Pas, even if the coating film has a certain degree of fullness and the viscosity is not too high, pull the brush during construction. This can be controlled by the ICI viscosity, which has a shear rate of about 10’s-1. In addition, high tensile viscosity can cause splashing problems. The tensile viscosity is related to the molecular weight of the water-soluble polymer thickener and the flexibility of the main chain. Polymer thickeners with high molecular weight and high flexibility in the main chain lead to high tensile viscosity, which leads to more splashes.

The low viscosity of leveling and sagging is conducive to leveling. Therefore, dyneon ptfe dispersion after the latex paint is applied, in order to level, its yield value should be slightly lower than 0.25Pa to maintain a low viscosity for a period of time. The driving force for leveling is the surface tension of the latex paint, not gravity, as evidenced by the fact that the paint on the ceiling can also level. After leveling, the yield value quickly returns to 0.5Pa. The viscosity increases to prevent sagging. The cause of sagging is gravity.

Under ideal conditions (ie, Newtonian fluid, no solvent volatilization, constant temperature), the sag speed of the wet coating on the vertical plane can be expressed by the following formula:
u=cpg r 2(19-2)
2m
Where v-sagging speed;
P—paint density:
Paint viscosity;
!——Coating thickness;
g~Acceleration of gravity.
It can be seen from formula (19-2) that the coating sag speed is inversely proportional to the viscosity of the coating, and proportional to the square of the coating film thickness. Increasing the viscosity of latex paint and reducing the thickness of the coating film can reduce sagging during application.