The Importance of Water Retention of HPMC
April 24th 2024
Let’s first analyze the common quality problems of redispersible latex powder, as well as the common methods and harms of poor manufacturers to reduce costs:
How to distinguish or distinguish the quality of redispersible latex powder? To find a way, start with analysis:
1. Production index analysis
Indicators are the basis for measuring the quality of redispersible latex powder. The standard index is the numerical expression of the basic performance of redispersible latex powder. Exceeding or not meeting the target range of redispersible latex powder has a direct impact on its performance. The main reasons for the abnormal indicators are production problems, such as backward production technology, backward or aging equipment, the use of cheap and inferior raw materials, and the lack of strict inspection of finished products. What’s more, some manufacturers are opportunistic in order to reduce costs, disregarding the quality, and charging shoddy goods. Therefore, it is necessary to choose a professional and reliable regular manufacturer.
2. Basic performance analysis
1. Redispersibility: The latex powder with good redispersibility can be redispersed to form a stable emulsion when it is dissolved in water. The particle size distribution is similar to the original emulsion. Rubber powders with poor redispersibility cannot be uniformly modified and may contain non-redispersible polymers.
2. Film formation of rubber powder: Film formation is the basis of mortar modification properties such as bonding. Poor film formation is generally caused by excessive addition of inorganic components or improper organic components. Redispersible latex powders of good quality have good film-forming properties at room temperature. Those with poor film-forming properties at room temperature mostly have polymer or ash quality problems.
3. Water resistance of the film: Redispersible latex powder has good film forming properties and also has good water resistance. Latex powders with poor water resistance generally contain more water-soluble polymers.
Three, application effect analysis
Determined according to application standards:
1. Dry bonding strength and water resistance bonding strength: poor bonding, polymer or ash quality problems. (JG149-2003)
2. Flexibility and impact resistance: The flexibility is not good, there are polymer quality problems, the flexibility decreases during use, and it may contain plasticizers.
3. Hydrophobic and non-hydrophobic: The surface is very hydrophobic, which can reduce the workability and bonding strength of the mortar.
4. Flow and rheology: The rheology is not good, and there are quality problems with polymers or additives.
5. Foaming and defoaming: abnormal foam performance, quality problems with polymers, ash or additives.
Several simple methods to identify redispersible latex powder:
1. Appearance method: Use a glass rod to thinly and evenly cover a small amount of redispersible latex powder on the surface of a clean glass plate, place the glass plate on white paper, and visually inspect the appearance of particles, foreign objects and coagulum .
2. Dissolution method: Take a small amount of redispersible latex powder and put it in 5 times the water, stir first, and then wait for 5 minutes before taking a look. In principle, the less insoluble matter precipitated to the bottom layer, the better the quality of the redispersible latex powder.
3. Ash method: Take a certain amount of redispersible latex powder, weigh it, place it in a metal container, heat it to about 600 degrees, burn it at high temperature for about 30 minutes, cool it to room temperature, and weigh it again. Good quality with light weight.
4. Film-forming method: Take a certain amount of redispersible latex powder and put it in a 1:1 aqueous solution, first pour the solution on a piece of flat glass, and then place the glass in a ventilated shade. After drying, observe that the transparency is high and the quality is good.
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