Pad printing ink for the perfect print! The Natron™ Series pad printing inks work with all pad printing machines. These printing inks achieve outstanding results on difficult to print substrates.
All of our inks get tested to provide the highest quality, opacity, and best adhesion. We manufacture these inks using the highest quality control standards. As a result our inks meet and exceed safety, environmental, and functionality standards. For more information about the Natron™ Ink series, visit pad printing inks.
High opacity silicone inks


The pad printing process transfers a two-dimensional (2-D) image onto a three-dimensional (3-D) object. This printing process uses a silicone pad to transfer an image from a printing plate (cliché) onto the object or substrate. This method of printing has gained popularity for printing onto odd-shaped objects. To print, you need an image. A printing plate (cliché) gets etched with an image. It is this image that the printing pad transfers to an object or the part by a silicone pad (tampon). Next, a cup filled with printing ink floods and removes the excess pad printing ink from the image. Then, a printing pad made of silicone picks up the image and transfers it onto the object. All these parts must be properly configured on the pad printing machine.

Pad printing cycle

Ink cup moves across the etched cliché and fills the etch with the printing ink. Carbide or ceramic ring then removes the excess ink from the etch. The silicone pad then presses down onto the ink, picks it up, and transfers the image onto the substrate. Now, the 2D image etched into the plate gets printed as artwork on a 3D product.
Note: For every new design and every additional color, you need a new printing plate. For example, a 2-color logo would use 2 plates; a 3-color logo requires 3 pad printing plates.

Additional Resources


Boston Industrial Solutions, Inc. manufactures and provides the best pad printing inks for any application. Our pad printing ink lines print with ease on a wide range of challenging surfaces with exceptional quality, performance, and ease.
Like any other pad printing ink, we make our inks with binders, resins, solvents, and pigments. But, unlike other inks, we use chemistry combined with AI to select the finest ingredients. As a result, our inks print on the widest range of applications. These include silicone, metal, nitrile rubber, and plastics, both treated and untreated. In addition, our inks have very high opacity, transfer onto the substrate with ease, and are very durable. These are some of the reasons why these are the best pad printing inks in the world.

Type of pad printing inks

Natron pad printing inks are either 1-or 2-component inks. The 1-component ink uses only a solvent. In general, the range of solvent usage ranges from 10 to 25% depending on the ink series. On the other hand, a 2-component ink requires a hardener and solvent.
There are different ratios of hardener needed depending on the type of ink. Typically, 10% of the ink weight of the ink should be added to the ink. A higher hardener ratio reduces the ink flexibility. Pad printing silicone inks uses a catalyst instead of a hardener. The catalyst vulcanizes the silicone ink. For silicone pad printing ink, the higher the catalyst, the faster the drying of the ink. Unlike hardener, the catalyst does not affect ink flexibility; it only affects the inks’ cross-linking speed. These ink additives are vital for getting the perfect print.

Additional Resources

pad printing ink for silicone
pad printing ink solvent


Boston Industrial Solutions, Inc. has solvent-based, UV and water-based pad printing inks.
The pad printing solvent alters the viscosity of the ink and the speed at which the ink dries and cures. There are several types of pad printing solvents rated by their evaporation rates. The evaporation rate is commonly known as the “speed” of the thinner.
To simplify the pad printing process, we formulate our inks to use similar solvents. This is cost effective way to speed-up pad printing professional’s job. Solvents evaporate out of the ink after pad printing, leaving solids behind. Immediately during printing, the solvent evaporates, making the ink tacky. After the solvent evaporates, the ink is easily released from the pad onto the substrate. To effectively print, please select the correct solvent for your ink series.


Pad printing hardener is an additive for pad printing ink. The hardener is also referred to as a catalyst or cross-linker. The function of the hardener is to improve the inks physical characteristics. These include resistance properties, such as ink adhesion and resistance to abrasion, chemicals, heat, water, and block.


Hardener is not only responsible for adhesion and physical resistance, but it is also responsible for enhancing the printed image. Like with our solvents, different hardeners work with different ink series. Also different applications require different ink-to-hardener ratio. This can vary from 0% (not adding hardener at all) to adding up to 25% of the inks weight. Note; that the hardener reduces the pot life of the ink. The higher the hardener ratio, the lower the inks pot-life.

pad printing ink hardener
silicone ink for printing silicone rubber - Natron SE Series - Boston Industrial Solutions


Pad printing silicone ink is a specialty ink for printing onto silicone rubber substrates. Silicone rubber is a difficult substrate for ink to adhere to. As a result, only a silicone based ink will adhere onto silicone. Like pad printing ink for glass, silicone ink requires heat to cure. We offer the Natron™ SE Series, DC Series, the SE-F silicone inks for medical applications. All these silicone inks are great options for decorating silicone rubber products.
The SE Series has the highest opacity and great printing pad release compared to any other inks in the world. It comes in over 40 standard colors, including the hyper colors. The SE Series is the world standard, the the yardstick for printing on silicone. All Natron™ silicone inks have excellent chemical resistance, scratching, bending, stretching. They also meet and exceed compliance, sustainability, regulations, and mil spec standards.
To pad print with silicone, you need our propriety pad printing solvents for silicone. These are TXM and SF Silicone solvents.

Additional Resources


To find the correct ink, you need to first understand the composition of your substrate. Some substrates are obvious as to their composition, e.g. glass, metal, and plastics. Other substrates such as silicone are not. As a result, it is important to test the part prior to selecting the ink to use. If you are not sure, call us to help you figure out your substrate composition.
Ink adhesion testing should be done before a production run. This will help determine the correct in and hence reduce wastage. Ink adhesion is affected by dirty / oily surfaces. Make sure the substrate is clean before adhesion testing and mass printing.
Lastly, we should take into consideration abrasion, chemical, and weather elements testing.
Natron™ ST tagless printing ink
Volta™ M150 1-Color pad printer


Printing ink could be dry but not cured. Dry ink means that the solvent has evaporated but the cross-linking has not taken place. Cured ink means that cross-linking has taken place. It is at this point that adhesion testing should be done.
Typically, perform adhesion testing 18 – 36 hours after printing. This wait time makes sure that the ink has achieved some cross-linking with the substrate. In some cases the printed product can take up to 6 days to achieve full cure.


Over a period of time, the hardener continues to harden. To reduce drying time and cure time, use heat. It should take 10 – 15 minutes to finish drying the ink. Heat does two things. It makes the solvent evaporate fast and speeds up the chemical reaction.
Note, when using the heat, you should let the part to cool down – wait for 30 minute before doing adhesion testing.


Color-matching is a process of mixing several colors to produce a new color. It involves copying a color from a known standard or target. In pad printing we use Pantone color system. We can however create colors from RAL and Hex systems. RAL is a type of color matching system. It is mainly used for the purpose of paintings and powder coatings. Pantone (PMS) is mainly used by graphic designers for color graphic printing.
At Boston Industrial Solutions we can use a wet sample or a customer’s specified PMS number. Alternatively, customers can send in specific substrate.
We use our in house developed AI to accurately determine the exact customer color. Using these ratios, then we formulate the exact color match for our customers. Out in house developed AI uses weight to mix the colors. All color formulation created are stored for future and repeat customer orders.
silicone ink color matching - silicone ink - boston industrial solutions
Natron SE Series Silicone Inks - USP MEM Elution Cytotoxicity Test - Certification - Boston Industrial Solutions


Different pad printing applications require different ink compliance, certifications, and specifications. Compliance basically ensures that a pad printing ink or a screen printing inks meet or exceed the final users specifications and certifications.
Ink certifications allows ink suppliers, such as pad printing, screen, ink jet, etc., to evaluate inks for use with specific label materials and conditions of acceptability.
An example of compliance it the CPSIA, which imposed testing requirements printing inks. This standard creates acceptable levels for several substances common in most consumer products, especially those designed for children, ages 0-12. It imposes restrictions on phthalates and lead. In addition, it imposes compulsory third-party testing by accredited laboratories specifically for lead. All Natron inks are heavy metals and phthalates free.

Other certifications

Specifications are requirements by the end user that pad printing inks have specific characteristics and meet certain standards. For example, Military (MIL-Spec)/Aerospace Qualified Ink-Military spec to MIL-I-43553 and AA56032. When properly applied and cured, the ink has excellent adhesion to metal, glass, and hard plastics. The ink is resistant to acids, alkalies, solvents, salt spray, and thermal shock. The Natron MG Series ink for glass, metals, ceramics, and hard plastics meets military spec for MIL-I-43553 and AA56032. This printing ink is a permanent, two-component, epoxy-based printing ink. Use the i-240x hardener, which cures at elevated and/or at room temperatures. For room temperature curing, perform adhesion testing 18–36 hours after printing. This wait time enables the ink to cross-link to the substrate. In some cases, the printed product can take up to 6 days to achieve full cure.



Choosing the right pad printing ink is the key to successfully completing a pad printing job. To buy the right printing ink, you ought to consider several factors. But first, let us explore the components of pad printing ink.

Printing ink components:

Ink pigment: This is usually in the form of a powder. The pigment gives the ink color and controls the ink’s opacity.

Resin is essential to an ink’s functionality. It impacts the ink characteristics of a finished ink. This includes gloss, adhesion, ink flow, and can also help disperse pigment.

Solvent: A dissolving vehicle for resin and pigment. The solvent also controls the ink’s viscosity and aids in the transport and drying of the ink. The solvent eventually evaporates, leaving the ink solids as the print. The solvent is also added during printing to alter the ink’s viscosity. The speed of the added solvent additionally impacts the ink pot life.

How to choose the correct ink for a substrate.

Substrate. Prior to printing, understanding and knowing the substrate is the most important factor. This will determine which type of ink to use. Different inks adhere onto different substrates. Choosing the wrong ink will almost certainly guarantee a filed print.

Resistance (Chemical and abrasion) and specifications. Different products get used for different applications and environments. A printed product will need to withstand the products use specifications. For example, if a product must withstand abrasion resistance, the ink must meet this requirement. If an ink will be cleaned with alcohol, then ink used must withstand this. Pad ink for glass must withstand dishwasher, hot-water, and detergents. Mil-spec prints must use Mil-spec inks. Tagless pad printing inks must pass Oeko tex and RSL certifications. Therefore, it is important to determine the type of resistance and specifications for the printed product.


Some applications call for a matte finish, while others call for a glossy finish. The SE silicone inks have a high gloss finish. This is not the case with ST Series inks for tagless printing and other rubber applications. The ST pad printing inks have a matte finish. Natron inks for glass, on the other hand, can be changed from a gloss to a satin to a matte finish.

Establish the cure and drying times. This is important because it determines the throughput. Air-cured inks dry to touch fast. Heat-cured pad printing inks require heat to dry and cure. For example, glass pad printing ink and silicone pad printing ink lines require heat to cure.
Application type medical grade, food grade, mil-spec, industrial grade, child safe inks etc. Pad printing ink must pass the specified application. Medial and food grade inks must pass all restrictions. It is important to use compliant inks that are free from heavy metals and forbidden chemicals. Boston Industrial Solutions manufactures non-toxic pad printing inks for all applications.
(Optional). This step is for “specialized applications,” e.g., silicone, nitrile, neoprene. Only Boston Industrial Solutions pad printing inks for these specialized applications. Ink for printing on silicone must be flexible.
136mm 136mm ink cup ring for kent pad printer machine
Volta™ M150 1-Color pad printer


The Natron™ UP Series is a specialty 1 or 2-component pad printing ink formulated for printing onto untreated polypropylene (PP).  This fast drying inks, exhibits high gloss, and is able to print on untreated polypropylene (PP). The product does not have to be pre-treated prior to printing. However, it is important to make sure that the substrate is clean – free from hand oils, etc.
In additional this ink works very well on treated polypropylene, treated polyester, lacquered surfaces, and polyurethane.
For superior adhesion and out door applications, use the i-300x hardener. The use of the hardener increases gives this pad printing ink for untreated polypropylene exceptional abrasion resistance and extended pot life. Like all of our other Natron Pad printing inks, this series is classified as NT (non-toxic) and is formulated with pigments which are free from heavy metals.