1. Common problems in putty powder
dry fast
This is mainly related to the amount of ash calcium powder added (too large, the amount of ash calcium powder used in the putty formula can be appropriately reduced) and the water retention rate of hydroxypropyl methylcellulose (HPMC), and it is also related to the dryness of the wall related.
Peeling and rolling
This is related to the water retention rate, which is easy to occur when the viscosity of hydroxypropyl methylcellulose (HPMC) is low or the amount added is small.
De-powdering of interior wall putty powder
This is related to the amount of ash calcium powder (the amount of ash calcium powder in the putty formula is too small or the purity of the ash calcium powder is too low, and the amount of ash calcium powder in the putty powder formula should be appropriately increased), and it is also related to the amount of hydroxypropyl methyl The amount of base cellulose (HPMC) is related to the quality, which is reflected in the water retention rate of the product. The water retention rate is low, and the time for ash calcium powder (calcium oxide in ash calcium powder is not fully converted to calcium hydroxide) is not enough. ,caused.
bubbling
This is related to the dry humidity and flatness of the wall, and it is also related to the construction.
pin point
This is related to cellulose, which has poor film-forming properties. At the same time, the impurities in hydroxypropyl methylcellulose (HPMC) react slightly with ash calcium. If the reaction is severe, the putty powder will be in the state of bean curd residue. It can’t be put on the wall, and it has no cohesive force at the same time. In addition, products such as hydroxypropyl methylcellulose (HPMC) mixed with carboxymethyl group also appear in this situation.
Volcanoes and pinholes appear
This is obviously related to the water surface tension of hydroxypropyl methylcellulose (HPMC) aqueous solution. The water table tension of hydroxyethyl aqueous solution is not obvious. It would be fine to do a finishing treatment.
After the putty dries, it is easy to crack and turn yellow
This is related to the addition of a large amount of ash-calcium powder. If the amount of ash-calcium powder is added too much, the hardness of the putty powder will increase after drying. If the putty powder has no flexibility, it will crack easily, especially when it is subjected to external force. It is also related to the high content of calcium oxide in ash calcium powder.
2. Why does the putty powder become thinner after adding water?
Hydroxypropyl methylcellulose (HPMC) is used as a thickener and water-retaining agent in greasy. Due to the thixotropy of hydroxypropyl methylcellulose (HPMC), the hydroxypropyl methylcellulose in putty powder The addition of HPMC also caused thixotropy after adding water to the putty. This thixotropy is caused by the destruction of the loosely combined structure of the components in the putty powder. This structure arises at rest and breaks down under stress. That is to say, the viscosity decreases under stirring, and the viscosity recovers when standing still.
3. What is the reason why the putty is relatively heavy in the scraping process?
In this case, the viscosity of hydroxypropyl methylcellulose (HPMC) generally used is too high, and some manufacturers use 200,000 yuan to make putty. The putty produced in this way has a high viscosity, so it will sink when batch scraping. a feeling of. The recommended amount of putty for interior walls is 3-5 kg, and the viscosity is 80,000-100,000.
4. Why do you feel that the viscosity of hydroxypropyl methylcellulose (HPMC) with the same viscosity is different in winter and summer?
Due to the thermal gelation of the product, the viscosity of the putty and mortar will gradually decrease with the increase of temperature. When the temperature exceeds the gel temperature of the product, the product will be precipitated from the water and lose its viscosity. The room temperature in summer is generally above 30 degrees, which is much different from the temperature in winter, so the viscosity is lower. It is recommended to choose a product with a higher viscosity when applying the product in summer, or to increase the amount of hydroxypropyl methylcellulose (HPMC), and to choose a product with a higher gel temperature.
Post time: Apr-12-2023