How to judge the quality of hydroxyethyl methylcellulose (HEMC)?

We need to conduct a comprehensive analysis from multiple dimensions including physical properties, chemical indicators, application performance, and production quality control. The following is the specific evaluation method: 1. Physical performance testing 2. Chemical index analysis 3. Application performance testing 4. Production and quality control

 

We need to conduct a comprehensive analysis from multiple dimensions including physical properties, chemical indicators, application performance, and production quality control. The following is the specific evaluation method:

1. Physical performance testing

 

1. Appearance and fineness
Color of high-quality HEMC: It should be white or off-white uniform powder, without caking and impurities. Yellow color, rough particles or foreign matter may be caused by impure production process or improper storage. The following picture shows the appearance of our KDOCEL HEMC100M. It can be seen intuitively that there is no-caking and uniform white.

2. Moisture content
The moisture content should be controlled at ≤6% (usual industry standard). Too high will cause the product to be easy to agglomerate and reduce stability. The moisture content of all our HEMC products is controlled below 6%, with a shelf life of 2 years.

2. Chemical index analysis

 

1. Viscosity
Viscosity is a key indicator of HEMC and needs to match the target application. According to customer needs, we can provide cellulose viscosity ranging from 320-80000mPas (Brookfield Viscosity).

2. Stability
The stability of HEMC is also one of the important indicators for identifying its quality. Under conditions of high temperature and high humidity, high-quality HEMC should be able to maintain its performance and quality stability. We take multiple samples for each batch of products to test the stability under various conditions.

3. Application performance testing

 

1. Solubility
High-quality HEMC: quickly disperses and dissolves in cold/hot water, without floccules or undissolved particles. Take a small amount of powder and add it to water and stir to observe whether a transparent and uniform colloid is formed.

 

2. Water retention
In building materials (such as mortar), water retention directly affects crack resistance and strength. The HEMC solution can be applied on filter paper to observe the evaporation rate of water; or the water retention rate of the mortar can be tested according to the standard (≥90% is preferred).

 

3. Anti-sedimentation
In coatings or slurries, high-quality HEMC can effectively suspend fillers and prevent stratification. Let the slurry containing HEMC stand for 24 hours and observe the bottom sedimentation.

 

4. Film-forming
The film should be uniform, transparent, flexible and crack-free. Apply the solution on a glass plate and dry it and observe the film state.

4. Production and quality control

 

1. Manufacturer qualifications and test reports
Suppliers are required to provide COA quality certificates, including data such as viscosity, ash content, pH value, etc.
Confirm whether the manufacturer has passed ISO or industry certification and whether the production process is stable. Our Kundu Chemical has passed ISO international quality standards and obtained the European Reach certificate, and has maintained a good reputation in the industry for many years.

2. Batch stability
The viscosity and solubility of different batches of products should be consistent, which can be tested by keeping samples for comparison. We Kundu Chemical keep samples for each batch. Ensure that the samples sent are the samples of the bulk goods, and ensure that the samples are consistent with the bulk goods.

3. Reasonable price
When the price is significantly lower than the market price, be vigilant, as cheap fillers (such as salt and starch) may be added. 

 

5. Common manifestations of inferior HEMC

1. The solution is turbid or has particles after dissolution.

2. The viscosity fluctuates greatly and is significantly affected by temperature or pH.

3. Poor water retention leads to rapid drying and cracking of mortar.

4. Too high ash content (>5%) indicates a lot of impurities.