I. What are UV viscosity-reducing dispersants?
UV viscosity-reducing dispersants are a class of polymer additives suitable for ultraviolet (UV) curing systems. They
combine the dual core functions of wetting and dispersing and reducing viscosity. In UV coatings and inks, they act like
a "molecular bridge"—one end adsorbs onto the surface of solid particles such as pigments and matting agents, while
the other end integrates into the matrix of resins and monomers. This bridge breaks up particle aggregation and reduces
friction within the system.
Unlike traditional solvent-based systems, the resins and monomers in UV curing systems have low molecular weights and
are rarely able to maintain stable pigment dispersions on their own. Therefore, these dispersants are more reliant on colloidal
stability. UV dispersants are VOC-free, perfectly aligning with the core advantages of UV technology: environmental friendliness
and fast drying.
II. Working Principles Hidden in the Microscopic World
UV viscosity-reducing dispersants work based on three key mechanisms:
Targeted adsorption:
Pigment-affinity groups in the molecule actively adhere to the surface of solid particles, forming a tight adsorption layer that
displaces air and moisture between the particles, achieving a "wetting" effect.
Charge repulsion: Some dispersants form a charge layer on the particle surface through ion exchange, creating an
"electrostatic shield" between particles and preventing aggregation and sedimentation.
Steric hindrance: Polymer chain segments form an elastic barrier around the particles, preventing adhesion even in the
event of particle collisions and reducing interparticle friction, significantly reducing system viscosity.
These three combined effects ensure uniform pigment dispersion and make viscous UV systems easier to apply.
III. Core Application Scenarios for Daily Life
(I) UV Coatings: From Matte Wood to Industrial Protective Finishes
In the UV coatings industry, dispersants are key to achieving a balance between texture and performance:
Optimizing Matte Effects: Matte coatings require the addition of a large amount of matting agent. Without dispersants,
the system viscosity increases dramatically, resulting in poor leveling and uneven coatings. Dispersants effectively disperse
matting agents, reducing viscosity while evenly orienting them, achieving a long-lasting, stable matte effect that can even
meet ultra-low gloss requirements (one spectra and below).
Upgrading High-Solid Coatings: They can increase the amount of pigment and filler added, allowing high-solid coatings
to be prepared without increasing viscosity, reducing solvent use and further reducing VOC emissions.
Adapting to Special Applications: From matte topcoats for wood furniture to protective coatings for industrial equipment,
dispersants can improve the coating's workability without affecting its post-curing properties, such as water and salt spray
resistance.
(II) UV Ink: An Invisible Aid for Precision Printing
The fast-drying properties of UV inks rely on UV curing technology, and dispersants play a role as "quality stabilizers":
Ensuring Color Uniformity: Dispersants ensure uniform dispersion of both organic pigments and high-surface-energy
carbon black, preventing color spots and color variations in printed products while also improving tinting strength and
gloss.
Improving Application Adaptability:
In fine-grained processes like inkjet printing, dispersants reduce ink viscosity, ensuring smooth, unclogging printheads. They
also maintain ink stability during storage, preventing pigment sedimentation and coarsening.
Multi-Substrate Compatibility: From paper and plastic sheets to metal cardboard, UV inks with dispersants adhere better to
substrates, making them suitable for a variety of printing methods, including lithographic, flexographic, and screen printing.
(III) Pigment Concentrates: A High-Concentration, Environmentally Friendly Solution
Pigment concentrates are the masterbatches for coatings and inks. The addition of dispersants allows them to achieve a
breakthrough in "high concentration, low viscosity":
They can increase pigment content to a higher level, allowing the production of resin-free or resin-containing concentrates.
This not only reduces transportation costs but also allows downstream companies to dilute as needed, reducing waste.
Dispersants can achieve stable dispersion for both inorganic pigments (such as red iron oxide and silica) and organic
pigments, preventing hard settling during storage.
IV. Key Considerations for Use
Timing of Addition:
The dispersant should be pre-mixed with the monomers and oligomers before adding the pigment or matting agent to
fully maximize its adsorption and dispersing properties.
Dosage Control: Adjust the dosage based on the pigment type. Generally, lower dosages are used for inorganic pigments,
while higher dosages are used for difficult-to-disperse pigments such as carbon black. However, optimal values should be
determined through experimentation to avoid overdosing that could affect curing.
Storage Conditions: Most dispersants should be stored in a cool, dark place at 15-35°C. Low temperatures may cause
turbidity, but heating will restore their properties without affecting their use.
V. The Value of Technology in the Environmentally Friendly Era
With stricter environmental regulations and the growing popularity of "low-carbon production," UV technology, with its
low energy consumption and zero VOC emissions, is becoming an industry trend. UV viscosity-reducing dispersants are
a key supporter of this trend. By optimizing formulations and increasing solids content, they help UV products achieve
the dual goals of "performance upgrades and environmental compliance," playing an irreplaceable role in the green
transformation of industries such as coatings and printing.
