hydroxypropyl methylcellulose HPMC in Plastering MortarFebruary 2nd 2023
Phenomenon: After the construction is completed and dried, the powder will fall off when touched by hand. In building materials, the addition amount of HPMC for wall putty is very low, only 0.1%-1%, but it plays an irreplaceable role and can significantly improve the water retention, fluidity and lubricity of building materials. Building materials added with HPMC are easier to mix and use, improve the work efficiency of construction workers, extend the open time, improve the bonding strength, and form a smooth and delicate surface coating.
The Cause of the Deflashing and Blistering
1. Interior wall putty powder with poorly timed polishing, the surface will fall off after drying and then polishing treatment.
2. Exterior wall putty powder with thin coating when finishing. In summer, when the temperature is high, the water evaporates quickly and the surface is not sufficiently cured, which makes it easy to remove the powder.
3. The product has exceeded its shelf life and the adhesive strength has significantly decreased.
4. The product has been stored improperly and the adhesive strength has decreased significantly after absorbing moisture.
5. High water absorption at the base level causes the putty to dry quickly and does not have enough moisture for curing.
The Solution of the Deflashing and Blistering
1. When polishing the interior putty surface, it is important to get the right polishing time. The best time to polish is immediately after the watermark on the putty surface disappears. Practice has shown that 1~2m2 of veneer should be levelled or polished.
2. After the exterior putty surface has dried, it should be properly polished and sprinkled with water. General maintenance is divided into two or more times. If necessary, use a clear closed primer mixed with water (1:5) as a second spraying for better results.
3. The product must be used within the warranty period. If the warranty period is exceeded, a test scraping must be carried out. construction only after passing inspection.
4. The product must pay attention to the waterproof treatment. It should be stored in a cool and dry place with the package intact.
5. In summer or under high temperature and windy conditions, it is best to wet the wall surface with water before applying the putty. Putty can be applied after the wall surface is clear of water.