General knowledge of paint: introduction to manufacturing process of paint (3)

Core tip: Section 3 composition of abrasive Due to the different grinding equipment, the type of grinding action is also different There are impact type, wipe type and impact wipe type The viscosity of impact Abrasives shall be small, while that of wipe Abrasives shall be large (a) Impact type; (b) troweling type The following table lists the classification of common grinding and dispersion equipment according to the way of cohesion Table 12.2 classification of depolymerization force types of grinding equipment Viscosity (high shear rate) equipment classification impact type mixed grinding type very high high medium low very low high speed impact grinding high speed disperser, vertical ball mill, horizontal ball mill sand Which is the price of Dajin diatom mud Recommended brief introduction: which is the price of Dajin diatom mud? How to buy genuine diatom mud? Guangdong diatom mud agent suggests placing a basin of cold water in the air conditioning room, so that the diatom mud wall can breathe effectively The feature of the breathing wall is obvious When the indoor air is dry, the diatom mud wall will release the absorbed water quickly Put it out to help regulate the indoor dry humidity It is suggested to place a basin of cold water in the air conditioning room, so that the wall of diatom mud can breathe effectively The feature of the wall that can breathe is obvious When the indoor air is relatively dry, the wall of diatom mud will absorb the water Coating home news: the third section abrasive composition due to the use of different grinding equipment, the type of grinding effect is also different There are impact type, wipe type and impact wipe type The viscosity of impact Abrasives shall be small, while that of wipe Abrasives shall be large (a) Impact type; (b) grinding type the following table lists the commonly used grinding dispersion equipment according to the different types of cohesion table 12.2 classification viscosity (high shear rate) equipment classification of the depolymerization type of grinding equipment impact type mixed grinding type very high middle and low very low high speed impact grinding high speed disperser, vertical ball mill, horizontal ball mill sand mill three roller grinder There are three obvious differences between the impact type of colloidal grinding and the wipe type of grinding equipment: (1) the best direction of the impact type force is perpendicular to the dispersed substance, while the best direction of the wipe type force is parallel to the dispersed substance (2) The viscosity of the abrasive slurry of the impact grinder must be small, while the viscosity of the abrasive slurry of the wipe grinder must be the largest (3) The impact type grinder requires the maximum speed, while the wipe type disperser has a small speed Fig 12.6 schematic diagram of ball mill, sand mill and three roller mill I composition of grinding materials of ball mill 1 Structural features and advantages of working principle: ① mixing and dispersing at the same time; ② simple and convenient operation Disadvantages: difficult to change colors Four working states: 2 Grinding medium steel ball, Al2O3, ZrO2 3 The amount of paint increased by 5-10% 4 The composition of the grinding material of the ball mill and the base material in the paint by the experimental method can actually be regarded as a dispersant to prevent the flocculation of the pigment The minimum amount of base material can reach the minimum viscosity and the maximum pigment volume content at the same time, so as to meet the requirements of the dispersion stage The best composition of the abrasive can be obtained by Daniel flow point method The method is as follows: (1) paint with 55% solid content is diluted to 10%, 15%, 20% by solvent Resin solution with 50% solid content (2) Accurately measure 20g of pigment in the beaker, add the resin solution to the pigment, stir with a glass rod while reaching Daniel's flow point, and record the volume of resin solution consumed (3) The volume of consumed resin solution is plotted by the concentration of each resin solution The lowest point of the U curve of the flow point is equivalent to the best composition of the abrasive when it is dispersed 5 The result of Daniel flow point method is reliable and the highest grinding efficiency can be obtained However, there are three problems in the industrial production: (1) due to the low viscosity of the paint in the paint slurry, the wear of the equipment is relatively obvious (2) The content of the base material in the abrasive is too low, which may lead to "solvent migration" and coarsening when further diluting (3) Because the slurry containing pigment is thick, it is difficult to transport by feeding pump In actual production, resin concentration slightly higher than the lowest flow point can be used Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,