We all know that putty powder is made by mixing Calcium hydroxide powder,Calcium hydroxide powder, hydroxypropyl methylcellulose and water.
Does putty powder fall off have anything to do with hydroxypropyl methylcellulose?
The main functions of hydroxypropyl methyl cellulose in putty powder are: thickening, water retention and convenient construction. Cellulose can thicken and suspend, make the solution uniform and consistent, and resist sag. Water retention properties make the putty powder dry slowly after painting, and assist the gray calcium to react under the action of water. Hydroxypropyl methyl cellulose is used to thicken and retain water. If the quality is too poor, the water retention effect will cause powder loss. It is recommended to use Obon Cellulose’s hydroxypropyl methylcellulose, which has a good water retention rate.
In order to accelerate the decomposition of ash calcium powder factory, the calcination temperature is generally increased to 1000～1100℃. Due to the large size of the limestone raw material or the uneven temperature distribution in the kiln during calcination, the lime often contains underfire lime and overfire lime. The calcium carbonate in the underfire lime is not completely decomposed, and lacks cohesive force during use, and cannot provide enough bonding strength for the putty, resulting in powder removal caused by insufficient hardness and strength of the putty.