Preface: With the diversified development of dispersants, various performance biased dispersants have been derived, including those that are biased towards stability, hue, viscosity reduction, and so on. In the pursuit of environmental protection, solvent based coatings are pursuing higher PVC and lower VOCs. At this time, the fluidity and uniformity of the slurry have become the primary issues that need to be addressed.

1. The problem of environmentally friendly high solid slurry

High solid slurry has a volume solid content of over 60% (reference: the typical range of PVC topcoat is 0.25-0.45), and the single coating film thickness is 1-4 times higher than traditional coatings, effectively reducing the number of coatings and VOCs, and many other advantages.

One of the challenges encountered in the production process of environmentally friendly high solid slurry is the decrease in fluidity and uniformity caused by exceeding the critical pigment volume concentration (CPVC). This is very common in carbon nanotube CNT slurry because the gaps between solid particles are precisely filled by the base material (such as polyacrylic acid resin), resulting in significant changes in rheological properties and performance

When too much powder is added beyond CPVC, it will lead to a decrease in the rheological properties and flowability of the slurry, resulting in inter particle gaps and residual bubbles, affecting the cross-linking density of the resin (adhesive), thereby reducing the corrosion resistance of the coating (water vapor and ions are more easily penetrated) and mechanical strength (such as adhesion and hardness). If necessary, the volume percentage of non-volatile matter (NVVp) in the base slurry can be measured using the international standard ISO 3233-1:2019

 

2. Improve and control PVC

The application mechanism of Tech-541 dispersant is to change the dispersion state of pigment/filler particles in high solid slurry, reduce particle gaps and improve particle arrangement, optimize the interaction between the base material and pigment, and achieve higher NVVp and lower VOCs in the slurry.

Rich application experiments have shown that Tech-541 can achieve a high pigment filling amount in the slurry, effectively reduce dispersion time, and has a wide compatibility, especially suitable for dispersing inorganic particles such as titanium dioxide and bentonite

2.1  Main Performance Measurement

We selected international products of the same type (competitors) for comparison, dispersing titanium dioxide and iron oxide yellow/red in a thermoplastic acrylic system, and horizontally comparing the performance differences between dispersants.

Liquidity : An Important Advantage

Liquidity : Tech-541-Thermoplastic Acrylic System Titanium Dioxide

Liquidity : Tech-541-Thermoplastic Acrylic System Iron Oxide Red

Tech-541 leads the way in performance, effectively reducing system viscosity and improving slurry flowability

Color display/anti floating color : Balanced performance

Color Display : Tech-541-Thermoplastic Acrylic System Titanium Dioxide

Color Display : Tech-541-Thermoplastic Acrylic System Iron Oxide Red

Color Display : Tech-541-Thermoplastic Acrylic System Iron Oxide Yellow

Comparing the color development tests, it was found that there was no significant difference in the color development of the four dispersants in the titanium dioxide system. In the iron red/iron yellow system, Tech-541、 Competitors A and B have similar color display, while competitor C has different performances

Coloring power : Tech-541-Thermoplastic acrylic system Iron oxide red

Floating color : Tech-541-Thermoplastic Acrylic System Iron Oxide Red

Coloring power : Tech-541-Thermoplastic acrylic system Iron oxide yellow

Floating color : Tech-541-Thermoplastic Acrylic System Iron Oxide Yellow

In the coloring power and float color tests, Tech-541 has a small color difference, achieving a good balance between the two properties. This means that the color remains consistent at different coating thicknesses and joints, and the low color difference allows construction personnel to use it with more confidence

Anti sinking property : long-lasting uniformity

Anti settling performance is one of the conditions for maintaining the continuous uniformity of the slurry. From the test (as shown in the above figure), it can be seen that Tech-541 has excellent anti settling performance. In all tests, Tech-541 only showed slight stratification, whereas competitor C exhibited severe stratification with increasing settling time

 

3. Summary

Tech-541 is a dispersant with excellent comprehensive performance, which is comparable to the international leading (competitor A) in overall performance. It has an advantage in flowability and exhibits excellent flowability for inorganic pigments such as titanium dioxide and iron oxide, with a good balance between float and color development.

Tech-541 is recommended for the preparation of slurries that require high fluidity, high powder filling, and long-lasting uniformity