Formulations of matting agent for polyurethane

a) The above formula design can also use 60/40 polyester or 50/50 polyester with a small amount of 70/30 polyester.

b) Recipe adjustment direction: when T-335 is added less in the formula (such as 2~3%), you can choose
Excess epoxy/T-335=2~2.5/1 curing ratio, then the leveling is better and the gloss is lower; when the amount added in the formula is larger (such as 4~4.5%), you can choose excess epoxy/T-335=2~1.5/1 curing ratio, then the surface is more delicate and the gloss is lower. According to the amount of T-335 in the formula, users can try to choose the excess epoxy/T-335** curing ratio to adjust the gloss and surface.

The sedimentation speed of titanium dioxide is about 20 times that of iron red. If it is not handled properly, it will float red and the surface color will become darker. Appropriate wetting and dispersing agents must be selected to keep them in a stable state. The Stokes formula only describes the settling speed, but the various pigment particles in the dispersion also undergo Brownian motion. Generally, the density is low and the particle size is small and the movement speed is fast. For example, honeywell specialty wax & additives inc ,  the movement speed of carbon black may be more than 1000 times that of titanium dioxide.

When making sky blue paint, people will use the combination of titanium white and phthalocyanine blue, but this combination often has the phenomenon of floating color and blooming. The reason is that titanium dioxide has high density, relatively large particle size, and slow movement speed; while phthalocyanine has low density, small particle size and fast movement speed. When TiO: settles and the phthalocyanine blue is in a dispersed and suspended state, a floating blue phenomenon will occur. However, due to the fast movement of phthalocyanine blue, the probability of collision is high. If there is no energy barrier protection, flocculation is easy to occur, the particles become larger, sedimentation occurs, and whitening will occur. Therefore, in this system, the floating blue, white floating or blooming is not fixed, and a more effective control method is to select the appropriate titanium dioxide, with a wetting and dispersing agent. For example, using R-830, Tego Glide 450 leveling agent as a wetting agent and Te goD is pers 610 as a dispersing agent can basically solve the above-mentioned disadvantages.

The settlement and Brownian motion in a dispersed system are not equal motions. Sedimentation will produce a concentration difference, and Brownian diffusion motion will make it uniform. If the sedimentation velocity is too large, the sedimentation volume will appear, the Brownian motion velocity is high, and the particles are uniform.