Floor coating dispersant: the "color magician" of the microscopic world
In the anti-slip floor of the underground garage, the artistic floor of the commercial space, and even the clean floor of
the electronic factory, we often see coatings with uniform colors and smooth surfaces. But what is less known is that
behind these perfect effects, there is a magical substance called "dispersant". It is like a magician in the microscopic
world. Through precise regulation of the molecular scale, it allows solid particles such as pigments and fillers to be
evenly distributed in the coating, and finally presents ideal decorative effects and physical properties.
1. The core role of dispersants: breaking the "agglomeration spell" of particles
Floor coatings are composed of resins, pigments, fillers, solvents and additives. The dispersion state of pigments and
fillers (such as titanium dioxide, calcium carbonate, talcum powder) directly affects the performance of the coating.
These solid particles carry electric charges on their surfaces and are easily attracted to each other through van der
Waals forces in liquids to form aggregates. If not fully dispersed, the coating will have problems such as floating color,
reduced hiding power, poor leveling, and even cracking or peeling of the coating film in severe cases.
Dispersants solve this problem through two mechanisms:
Chemical anchoring: One end of the dispersant molecule carries an anchoring group such as carboxylic acid or phosphate,
which can form a chemical bond or hydrogen bond with the pigment surface and firmly adsorb on the particle surface.
Steric hindrance:
The solvated chain segments such as polyether and polyester at the other end of the dispersant stretch in the medium to
form a protective layer several nanometers thick. When the particles approach, the chain segments compress to generate
entropy repulsion, preventing agglomeration. This mechanism is particularly critical in solvent-based floor coatings, which
can ensure that the pigment is suspended for a long time.
2. The "superpower" of dispersants: comprehensive empowerment from laboratory to construction site
1). "All-rounder" to improve coating performance
Color performance: Evenly dispersed pigments can give full play to hiding power and tinting power.
Leveling optimization: Dispersants reduce system viscosity and eliminate defects such as shrinkage cavities and pinholes.
Storage stability:
Through the steric stabilization mechanism, dispersants prevent pigment sedimentation and stratification. Experiments
show that the paint with 2% dispersant added can maintain no hard precipitation for 6 months in the 50℃ accelerated aging
test, significantly extending the shelf life.
2). "Accelerator" of construction efficiency
Shortened grinding time: dispersant wets the pigment surface in advance, reducing grinding energy consumption.
Improved spraying fluency:
the viscosity of evenly dispersed paint is stable, avoiding clogging of the spray gun. In the automated spraying production line,
dispersant can reduce the fluctuation of paint delivery pressure by 50%, improve the consistency of spraying quality, and reduce
the rework rate.
3). "Balancer" of environmental protection and cost
Reduced VOC emissions:
high-efficiency dispersants can reduce the amount of solvent used. For example, the super dispersant synthesized by controlled
free radical polymerization technology has a concentrated molecular weight distribution and can achieve excellent dispersion
effect at a low addition amount (1-2%), thereby reducing the solvent ratio and meeting environmental protection requirements.
Extended paint life:
evenly dispersed fillers can better resist wear and UV aging. In underground garage floors, the service life of coatings using
high-quality dispersants can be extended from 5 years to more than 8 years, and the comprehensive cost can be reduced by
40%, reducing long-term maintenance costs.
3. "Selection Guide" for Dispersants: Wisdom of Adapting to Local Conditions
1). Select by System Type
Solvent-based floors: Polyphosphate esters and high molecular weight polyurethane dispersants are preferred. They have
good compatibility with solvent-based resins such as epoxy resins and polyurethanes, excellent temperature resistance, and
can withstand high-temperature construction environments.
Water-based floors: Anionic (such as sodium carboxylate) or non-ionic dispersants (such as glycol ethers) are required to
avoid reactions with carboxyl groups in water-based resins.
2). Matching by pigment characteristics
Inorganic pigments (such as iron oxide, titanium dioxide): Select dispersants with acidic anchoring groups (such as phosphate esters and carboxylic acids) to firmly adsorb through ionic
bonds.
Organic pigments (such as phthalocyanine blue, carbon black): Basic anchoring groups (such as amines, quaternary ammonium salts) or hydrogen bond donors (such as polyhydroxy
compounds) are required to enhance the interaction force.
Compound pigment system: Use dispersants containing multiple anchoring groups (such as phosphate-polyether
copolymers) to disperse inorganic and organic pigments at the same time, simplifying the formula design.
3). Construction process considerations
High shear construction (such as spraying, roller coating): Select dispersants with lower molecular weight (5000-10000)
to avoid excessive chain length leading to decreased leveling.
Low shear construction (such as scraping, self-leveling): High molecular weight (20000-50000) dispersants are required
to provide stronger steric stabilization to prevent sedimentation.
4. Future trends: The rise of smart dispersants
As floor coatings develop towards high performance and multifunctionality, dispersant technology is also constantly innovating:
Responsive dispersants: Trigger chain conformation changes through pH or temperature to achieve "dispersion on demand".
For example, when stored at low temperatures, the chain segments shrink to reduce viscosity, and when heated up during
construction, they expand to enhance stabilization and adapt to different construction environments.
Nanocomposite dispersant: Inorganic nanoparticles (such as silica) are introduced into the dispersant structure, providing
a dual stabilization mechanism of chemical anchoring and physical isolation, which is suitable for high-solid content coatings
and improves the density of the coating.
Bio-based dispersant: Using renewable resources such as vegetable oils and sugars as raw materials, it reduces
dependence on petroleum-based products. At present, polyester-based bio-based dispersants have been industrialized
in water-based epoxy flooring, taking into account both environmental protection and performance.
Conclusion
From the anti-slip floor of the underground garage to the clean floor of the electronics factory, the dispersant has always
been silently guarding the quality of the coating behind the scenes. It uses precise control at the molecular scale to weave
countless microscopic particles into a uniform macroscopic network, so that every inch of the ground can show the best
performance and beauty. With the advancement of materials science, this "invisible magician" will continue to unlock more
possibilities and bring more environmentally friendly, efficient and intelligent solutions to the floor coating industry.
