Views: 2 Author: Site Editor Publish Time: 2022-01-22 Origin: Site
Cellulose ether HEMC is Hydroxyethyl Methyl cellulose which is used as a thickening agent water retention agent in the application of Skim Coat, due to the thixotropy of cellulose itself, the addition of HEMC cellulose ether in Skim Coat powder also led to the thixotropy of Skim Coat with water. This thixotropy is caused by the destruction of the loosely bound structure of the components in Skim Coat powder. This structure is formed at rest and disintegrates under stress. That is to say, the viscosity decreases at agitation and recovers at rest.
When we use cellulose ether HEMC in Skim Coat powder, there will often be some problems, let us do not know why happens in Skim Coat powder !
One: Dry fast. This is basically the amount of gray calcium and fiber water retention rate, but also related to the dryness of the wall.
Two: peel and roll. This is related to the water retention rate, the low viscosity of cellulose is prone to this situation or low dosage.
Three: powder. This is related to the amount of gray calcium, but also the amount of cellulose and quality of the relationship, reflected in the product water retention rate, water retention rate is low, gray calcium hydration time is not enough, caused.
Four: blistering. This is related to the dry humidity and flatness of the wall, but also related to the construction.
Five: needle point. This is related to cellulose, its film formation is poor, but also the impurities in cellulose and gray calcium has a slight reaction, if the reaction is violent, the Skim Coat powder will present the state of bean curd residue. Can not be on the wall, at the same time there is no bond, in addition to cellulose mixed with carboxylated products also appear in this situation.
Six: volcanic caves and small holes. This is obviously related to the surface tension of hydroxyehtyl methyl cellulose aqueous solution and the surface tension of hydroxyethyl aqueous solution is not obvious for receiving light treatment will be good
Seven: Skim Coat dry after easy cracking, yellowing. This is related to the amount of gray calcium, the amount of gray calcium, resulting in the increase of the hardness of Skim Coat powder after drying, only hardness without flexibility is easy to crack, especially by external force is easier to crack. Also with gray calcium in the calcium oxide content is high.
Skim Coat is heavy in the scraping process?
In this case, the viscosity of cellulose is too high. Some manufacturers use 200 thousand of cellulose to make putty. The Skim Coat made in this way is high in viscosity, so it feels heavy when scraping. Interior wall be bored with child proposal add quantity is 3, 5 kilograms, viscosity is 8, 100 thousand.
Why does the Skim Coat and mortar made with the same viscosity HEMC cellulose in winter and summer feel viscosity is different?
Due to the thermal gelation of the product, the viscosity of the product will gradually decrease with the increase of temperature. When the temperature exceeds the gel temperature of the product, the product will be precipitated out of the water, thus losing the viscosity. In summer, the room temperature is generally above 30 degrees, which is much different from the temperature in winter, so the viscosity feels low. In summer, it is suggested to choose products with a higher viscosity or increase the dosage of cellulose, and then choose products with a higher gel temperature.