Pad printing ink additives are specialized materials which are added to pad printing formulations to enhance performance, stability, and print quality. Among other things, these additives increase adhesion, change viscosity, enhance flow characteristics, and strengthen resistance of material towards environmental stresses. Typical additive categories include thickeners, dispersants, adhesion promoters, and anti-foaming agents. By carefully selecting and combining these elements, the ideal ink composition for certain surfaces and applications may be obtained, ensuring exceptional print clarity, color vibrancy, and longevity. Moreover, additives can prevent issues like bleeding and smearing and hasten the drying process. Understanding role of additives is essential to achieving consistent, excellent results in pad printing, which makes them a vital component in the development of complex ink systems.
Both pigment and binder materials are present in pad printing ink. While the binder makes sure the ink can stick to the substrate, the pigment adds visual impact. Performance of basic pad printing inks can be improved by adding a variety of additives.
Pad Print Ink Additives
Hardeners
- The purpose of adding hardener in pad printing ink is to improve adhesion, durability, and resistance.
- It helps the ink to bond with tough surfaces, enhances scratch and chemical resistance, and speeds up curing.
- The choice of the right hardener depends on various factors, such as the type of resin, the desired curing speed and the application temperature.
- Using the right ratio is crucial for achieving optimal results without making the ink too brittle.
Thinners
- Thinner is used to reduce the viscosity of pad printing ink, making it easier to transfer and flow smoothly during printing.
- Basically, a solvent, diluent, oil, or other substance added to a printing ink to reduce its tack, body, and viscosity.
- It helps achieve the right ink consistency, improving coverage and drying time.
- However, using too much can weaken the ink’s adhesion and durability.
Retarders
- A low-volatility solvent added to a printing ink to slow down the rate at which the ink dries by impeding solvent evaporation, commonly used in flexographic, gravure, screen printing, and heat set inks.
- Retarders that slow an ink’s drying time by preventing oxidation from taking place are called antioxidants.
Adhesion Modifiers
- The adhesion modifiers incorporate various functional groups that are available on the surface, with the intention of interacting with the surrounding environment.
- In pad printing it enhances the ink’s bonding capability to difficult substrates like metals, plastics, or glass.
- It optimizes surface interaction, ensuring strong, long-lasting prints even on low-energy surfaces, essential for high-performance, industrial-grade applications.
Matting Agent
- The addition of matting agent in pad printing ink reduces gloss to create a matte finish.
- It modifies the surface texture by scattering light, providing a non-reflective, softer appearance.
- Ideal for achieving a premium, matted look on various substrates, especially in applications where a matte aesthetic or reduced glare is desired.
Levelling Agent
- A levelling agent in pad printing ink ensures smooth, uniform ink flow by reducing surface tension.
- Helps prevent defects like streaks, pinholes, or uneven coverage, resulting in a flawless, high-quality print.
- Crucial for maintaining consistent surface appearance, especially in demanding industrial printing applications.
- Typically, silicone or acrylic-based, it reduces surface tension, allowing ink to spread evenly for a smooth finish.
Primer
- The application of primer in pad printing enhances ink adhesion on challenging substrates like glass, metals, and plastics.
- It acts by pre-treating the surface which improves its receptiveness to ink, ensuring better durability and resistance.
- Essential for high-quality, long-lasting prints, especially in industrial applications where adhesion is critical.
- Composed of adhesion-promoting resins.
Selection of the perfect pad printing ink for your projects
The experts at SPINKS WORLD can identify the best formulation for your projects after considering a wide range of factors, including:
Substrate
Industry
Color
Opacity
Ink type
Adhesion requirements
Abrasion requirements
Need for pretreatments
All inks do not require additives
To identify if your ink is single or double component, check the manufacturer’s instructions or technical data sheet (TDS).
Single Component
It comes ready to use and does not require any additives or hardeners. You only need to adjust with thinner if necessary.
Two-Component
Requires the addition of a hardener (typically at a specified ratio, like 10:1 ink to hardener) before use. The TDS will indicate the need for a second component (hardener).
Tools needed for Pad printing ink mixing
Gloves
Cup
Long mixing Stick
Digital Weighing balance
The ink preparation
Step 1 : Mix Pad Print Ink
The ink can must be rotated with hand, while using a long mixing stick in other hand to evenly distribute the binder throughout your ink. Make sure to push the mixing stick all the way down to the bottom of the ink can to ensure the pigment and binder are completely mixed throughout. The mixing stick must be pushed all the way down to the bottom of the ink can and back up again as the can is rotated all the way around. Very quickly the binder will have been forced back into the pad print ink pigment so that the final ink will have the appropriate ratio of pigment to binder.
Step 2 : Pour Desired Amount of Ink into a Cup for Mixing
Spinks Intelligent labels provide high-quality badges, including embroidered badges, PU badges, Silicone Badges, Woven Embroidered Badges, and many more.Place the cup on a digital scale and zero it out. Then carefully pour the desired amount (g) of ink into the cup. It must be made sure that the pouring is not happening from a point on the can where the label displays key information. Instead, the ink should be poured from the back side of the can where no key information is included on the label. This way, if any pad print ink were to spill while getting poured any covering key information on can label will not be covered.
Step 3 : Add Pad Print Ink Hardener
The pad print ink additives must be added one at a time. Place the cup (now containing desired amount (g) pad print ink) back on your digital scale and zero it out again. The ratio of pad print ink to hardener will depend on your unique application or based on the information provided in the technical data sheet. Once the pad print ink hardener is added, mix it thoroughly throughout the ink using the method described in Step 1 above. Let the hardener set in the ink for about 15-30 seconds.
Step 4 : Add Pad Print Ink Thinner
Place the cup {now containing desired amount (g) of pad print ink and proportionate amount of pad print ink hardener} back on the scale and zero it out one more time. Now this mixture can be added with thinner. The pad printing ink supplier can be trusted for the proper ratio of ink + hardener: thinner to be used. Then all these three components must be mixed in the cup thoroughly using a wooden stirring stick.
Conclusion
To achieve the best results when adding additives to pad printing ink, it’s important to incorporate them one at a time. After each additive is added, mix thoroughly using a stirring stick that reaches all the way to the bottom of the ink container. Repeat this process for every additive. Properly preparing your pad printing ink ensures consistent, high-quality prints with reliable repeatability.
