Building special hydroxypropyl methyl cellulose to avoid moisture infiltration to the wall, will be just the right amount of moisture can stay in the mortar cement produce good performance in water and the role of the hydroxypropyl methyl cellulose in the mortar can be proportional to the viscosity, the higher the viscosity of hydroxypropyl methyl cellulose water retention will be better.
Once the moisture of hydroxypropyl methyl cellulose is too high, the water retention of hydroxypropyl methyl cellulose will decline, and it will directly lead to the construction efficiency of hydroxypropyl methyl cellulose. We are also familiar with the things will be more easy to make mistakes, we should always keep fresh, we will receive unexpected results.
The apparent viscosity is an important index of hydroxypropyl methyl cellulose. The common measurement methods are rotational viscosity measurement, capillary viscosity measurement and fall viscosity measurement.
Previously, hydroxypropyl methyl cellulose was determined by capillary viscosity measurement, using a Uhnscher viscometer. The measurement solution is usually an aqueous solution of 2, and the formula is: V=Kdt. V is the viscosity in seconds, K is the constant of the viscometer, D is the density at constant temperature, and T is the time it takes to go from top to bottom of the viscometer in seconds. This way of operation is more complicated, if there is insoluble material, it is easy to cause errors, it is difficult to identify the quality of hydroxypropyl methylcellulose.
The problem of building glue stratification is a big problem encountered by customers. First of all, the problem of raw materials should be considered for building glue stratification. The main reason for building glue stratification is the incompatibility between polyvinyl alcohol (PVA) and hydroxypropyl methylcellulose (HPMC). The second reason is that the mixing time is not enough; There is also the building glue thickening performance is not good.
In building glues, instant hydroxypropyl methylcellulose (HPMC) must be used because HPMC is only dispersed in water and does not really dissolve. About 2 minutes, the viscosity of the liquid slowly increases, forming a transparent viscous colloid.
Hot soluble products, in cold water, can be quickly dispersed in hot water, disappear in hot water, when the temperature drops to a certain temperature, viscosity slowly appears, until the formation of transparent viscous colloid. Hydroxypropyl methylcellulose (HPMC) in the building glue added amount is recommended for 2-4kg.
Hydroxypropyl methyl cellulose (HPMC) in the building glue chemical stability, mildew, water retention effect is good, and is not affected by the PH change, viscosity from 100 000 S – 200 000 S can be used. But in the production is not the higher the viscosity is better, the viscosity and bond strength is inversely proportional, the higher the viscosity, the strength is smaller, generally 100,000S viscosity is appropriate.
Post time: Sep-16-2022