mortar additive hpmcMay 11th 2023
The lowest film-forming temperature is an important indicator of redispersible latex powder, the English abbreviation MFFT.
The lowest film-forming temperature refers to the lowest temperature at which the polymer particles in the emulsion have sufficient mobility to condense each other into a continuous film. In the process of forming a continuous coating film from a polymer emulsion, the polymer particles must form a tightly packed arrangement. Therefore, the conditions for forming a continuous film are not only the dispersion of the emulsion, but also the deformation of the polymer particles, that is, when water The capillary pressure generates considerable pressure between the spherical particles, and the closer the spherical particles are arranged, the greater the pressure increases. When the particles contact each other, the pressure generated by the volatilization of water forces the particles to be squeezed and deformed to bond to each other to form a coating film. Obviously, if the polymer particles of the emulsion of a harder agent are mostly thermoplastic resins, the lower the temperature, the greater the hardness and the more difficult it is to deform. Therefore, there is a problem of the minimum film-forming temperature. That is, under a certain temperature condition, after the water in the emulsion volatilizes, the polymer particles are still in a discrete state and cannot be integrated, so the emulsion cannot form a continuous uniform coating film due to the evaporation of water; and Above this specific temperature, when the water evaporates, the molecules in each polymer particle will penetrate, diffuse, deform, and gather to form a continuous transparent film. This lower limit of the film-forming temperature is called the minimum film-forming temperature.
The lowest film-forming temperature is an important indicator of Hebei Dezni Chemical’s redispersible latex powder. It is especially important to use the emulsion in the low temperature season. Take appropriate measures to make the polymer emulsion have a minimum film-forming temperature that meets the requirements of use. For example, adding a plasticizer to the emulsion can make the polymer softer, so that the minimum film-forming temperature of the emulsion is significantly reduced, or the minimum film-forming temperature Higher polymer emulsions use additives and so on.
Therefore, the minimum film forming temperature is an indicator of the construction temperature of the project. Generally speaking, the lower the minimum film forming temperature, the better the workability.
The minimum film forming temperature of the redispersible latex powder VAE produced by Hebei Dezni Chemical Technology Co., Ltd. is generally between 0℃～10℃, but the more common one is 5℃. At this temperature, the latex powder is continuous On the contrary, below this temperature, the film of latex powder will no longer be continuous and will break.