Water-based coating defoamer composition ratio
The ratio of Si-H to C=C of polyether modified polysiloxane is 1:1.1, the polyether dosing time is 3 hours, the reaction time is 6 hours, the reaction temperature is 130℃, and the active hydrogen conversion rate is 82.8%. The study shows that the silicone defoamer formulated with polyether modified polysiloxane has excellent defoaming effect in water-based coatings, and the foam inhibition performance is durable and compatible with the system.
If the viscosity of the added defoamer is less than the viscosity of the thick paste coating, it will easily produce incompatibility and affect the color and gloss of the coating, such as micronized ptfe chemical compatibility. Therefore, when choosing defoamer for thick paste coating, it is necessary to choose defoamer with higher viscosity in order to be well compatible with it and remove the air bubbles in the system.
Due to the high viscosity of the thick paste coating itself, if a large number of bubbles are generated in the system, they basically will not appear on the surface. Therefore, when choosing defoamer, you need to pay attention to whether the defoamer can remove the air bubbles in the system, so as to achieve the defoaming effect and not affect the coating effect when using it.
Because of the high viscosity of thick paste coating. If the defoamer chosen in the system has poor dispersion performance, it will not work well and will even float, thus affecting the performance of the whole coating system.
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