The "invisible hero" of water-based printing: How does a wetting agent improve ink performance?
In the colorful world of printing, water-based printing occupies an important position with its advantages such as
environmental protection and low cost. From exquisite book covers to fashionable packaging boxes, from gorgeous
posters to practical leaflets, the achievements of water-based printing can be seen everywhere. In this process,
there is such an "invisible hero" - wetting agent, which plays a key role in improving ink performance although it is
not obvious. Today, let us unveil the mystery of wetting agent and explore how it helps water-based printing.
Improve ink fluidity and make printing smoother
Imagine how difficult the printing process would be if the ink was like a sticky syrup and it was difficult to flow
smoothly in the printing equipment. The wetting agent is like a magical "lubricator" that can significantly improve
the fluidity of the ink.
The wetting agent molecule has a unique structure, with one end being hydrophilic and the other end being oleophilic.
When it is added to water-based ink, the hydrophilic end interacts with water molecules, while the oleophilic end
combines with resins, pigments and other components in the ink. This interaction breaks the tight bond between the
components in the ink, reduces the cohesive force of the ink, and allows the ink to flow more easily between the ink
rollers, printing plates and other parts of the printing press.
In the process of high-speed printing, good fluidity is essential. It ensures that the ink is evenly distributed on the
printing plate to avoid ink accumulation or ink breakage. For example, when printing large-format posters, if the ink
has poor fluidity, some areas may be too dark and some areas too light, seriously affecting the printing quality. With
the help of wetting agents, the ink can be quickly and evenly filled into the graphic part of the printing plate, and
then smoothly transferred to the substrate, making the printing process smoother and more efficient.
Enhance ink wettability and improve printing adhesion
In water-based ink printing, the ink must be firmly attached to the surface of the substrate to present a clear and
lasting image. The wetting agent plays the role of a "bridge" in this process, which can enhance the wettability of the
ink to the substrate.
Different substrates have different surface properties, some are smooth, some are rough, some are hydrophilic, and
some are hydrophobic. Wetting agents can reduce the surface tension of ink, making it easier to spread on the surface
of the substrate. When the ink contacts the substrate, the wetting agent molecules will quickly form an interfacial film
between the ink and the substrate, reducing the interfacial tension between the two and promoting close contact
between the ink and the substrate.
Taking paper printing as an example, there are many tiny pores and fibers on the surface of paper. Wetting agents
can allow ink to better penetrate into these pores, form a mechanical fit with the paper fibers, and enhance the
adhesion between the ink and the paper through chemical bonding and other methods. In this way, the printed
text and images will not fade or fall off easily, and can maintain good printing effects even under long-term friction
and environment. For other substrates such as plastics and metals, wetting agents can also play a similar role to
improve the adhesion of ink on different materials.
Adjust the drying speed of ink and control the printing rhythm
The drying speed of ink has an important impact on printing quality and production efficiency. If the drying is too fast,
the ink may dry prematurely on the printing plate, causing plate blockage; if the drying is too slow, the printed product
is prone to sticking when winding or stacking. The wetting agent is like a precise "regulator" who can skillfully adjust the
drying speed of the ink.
The wetting agent can adjust the drying time by affecting the evaporation rate of water in the ink. It can form hydrogen
bonds and other interactions with water molecules to slow down the volatilization of water. In the early stage of printing,
an appropriate amount of wetting agent can ensure that the ink has enough time to spread and adhere on the printing
plate and substrate to avoid affecting the printing quality due to too fast drying. In the later stage of printing, as the
wetting agent gradually evaporates or reacts with other ingredients, the drying speed of the ink will gradually accelerate,
ensuring that the printed product can be dried in time, which is convenient for subsequent processing and handling.
For example, in some packaging printing that requires high-speed printing and strict drying time requirements,
by reasonably adding wetting agents, the drying speed of the ink can be accurately controlled, so that the printing
machine can run at a higher speed while ensuring quality, greatly improving production efficiency.
Stabilize the ink system to ensure printing consistency
During the water-based ink printing process, the performance of the ink needs to remain stable to ensure the consistent
quality of each batch of printed products. However, the various components in the ink may be affected by environmental
factors such as temperature, humidity, and light, resulting in changes in performance. The wetting agent is like a loyal
"guardian" that can stabilize the ink system.
It can prevent the pigment particles in the ink from agglomerating and precipitating. The uniform dispersion of pigment
particles in the ink is the key to ensuring bright and accurate printing colors. The wetting agent can form a protective
film on the surface of the pigment particles to prevent the mutual attraction and aggregation between the particles.
At the same time, it can also adjust the viscosity and pH value of the ink to keep it stable within a certain range.
In different seasons and climatic conditions, the ambient temperature and humidity can vary greatly. Without the
stabilizing effect of the wetting agent, the performance of the ink may fluctuate with changes in the environment,
resulting in problems such as different shades of color and gloss of the printed products. With the addition of the wetting
agent, the ink can maintain relatively stable performance in various environments, ensuring that each batch of printed
products has consistent quality and meeting customers' high requirements for printed products.
As the "invisible hero" of water-based ink printing, wetting agents significantly improve ink performance by improving
ink fluidity, enhancing wettability, adjusting drying speed and stabilizing ink systems, providing a strong guarantee for
high-quality water-based ink printing. In the future development of printing technology, wetting agents will continue
to be optimized and innovated, and continue to bring more surprises and breakthroughs to the printing industry.
