Questions about You Should Know about HPMCMarch 23rd 2023
HPMC can be tailored to the viscosity and gel time required to improve the quality of your product. Increase the viscosity of the product system to achieve the desired physical properties, change the product flow to achieve the desired appearance, increase product solids content to reduce material cost, and prevent paint sagging and ensure mechanical properties and stability.
How many types of HPMC are there?
HPMC can be divided into quick-soluble type and hot-soluble type.
The instant soluble type disperses rapidly in cold water and disappears in water. At this time, the liquid has no viscosity, because HPMC is only dispersed in water, not really dissolved. After about 2 minutes, the viscosity of the liquid gradually increases and forms a transparent viscous gel. It can be used in a wide range of applications, including putty powders and mortars, as well as liquid glues and coatings.
Heat-soluble type, in the case of cold water, can be quickly dispersed in hot water and disappears in hot water. When the temperature drops to a certain temperature, it gradually appears viscous until it forms a transparent sticky colloid. Hot soluble type can only be used in putty powder and mortar. In liquid glues and paints it will appear caking and cannot be used.
What is the content of HPMC in putty powder?
The amount of HPMC used in practice varies depending on the climate, temperature, quality of the local calcium ash, formulation of the putty powder, “quality required by the customer”. Generally speaking, it is between 4 kg and 5 kg.
What is the viscosity of HPMC?
Generally 100,000 for wall putty powder and 150,000 for mortar with higher requirements. Moreover, the most important role of HPMC is to retain water, followed by thickening.
In putty powder, as long as the water retention is good and the viscosity is low (70,000-80,000), it is also possible. Of course, the higher the viscosity, the better the relative water retention. When viscosity exceeds 100,000, viscosity has an effect on water retention. It is not too great.
What are the causes of putty powder blistering?
In putty powder, HPMC plays the role of thickening and water retention in the construction. It should not be involved in any reaction.
The reason for foaming may be too much water. Or, if the base layer is not dry and people scrape a new layer of putty on top, it also tends to foam.
What is the relationship between the viscosity of HPMC and temperature?
The viscosity of HPMC is inversely proportional to the temperature, i.e. the viscosity increases as the temperature decreases. The viscosity of the product we usually refer to is the result of a 2% aqueous solution at a temperature of 20 degrees Celsius.
In practical application, in areas with large temperature difference between winter and summer, it should be noted that it is recommended to use lower viscosity in winter, which is more conducive to construction. Otherwise, when the temperature is low, the viscosity of cellulose will increase and the hand feeling will be heavy when scraping.
What is the function of HPMC in the construction industry？
It is the water retaining agent and retarder of cement mortar, which makes the mortar pumpable. the water retention of HPMC makes the slurry not to crack too quickly after construction and improves the strength after hardening.
Used as a binder in mortar, plaster, putty powder or other building materials to improve spreading and extend working time. Used as paste tile, marble, plastic decoration, paste enhancer, also can reduce the amount of cement.
Improves uniformity, facilitates plastering, improves anti-sagging, enhances fluidity, improves pumping capacity and increases work efficiency. Adjusts the consistency of mortar, forms a high-quality surface floating layer, promotes mortar strength, improves lubricity and plasticity, and thus improves overall construction progress.