Although most consumers have never heard of MEK-based ink before, they have likely seen MEK-based product markings on countless items in the grocery store, pharmacy, and even in their own homes.
MEK is an abbreviation for methyl-ethyl-ketone, a colorless liquid solvent used to make a variety of industrial products, including cleaning agents, synthetic rubbers, resins, and paint. However, for those familiar with inkjet printing, MEK is likely best known for its presence in solvent-based ink formulas.
Commonly used in continuous inkjet and thermal inkjet printers, MEK-based inks are valued for their quick drying times and great surface adhesion. These qualities make them great choices for printing on substrates that don’t allow liquid ink to sink beneath the surface (i.e. non-porous substrates).
Here, we take a closer look at MEK as a compound as well as the most common applications of MEK-based ink formulas.
Also known as “butanone,” methyl-ethyl-ketone is a naturally occurring organic compound with corrosive and oxidizing properties. Commonly used throughout the world as an industrial solvent, MEK is a volatile compound, meaning it vaporizes at room temperatures. This quick vaporization is key to the value of MEK to ink manufacturers.
Inkjet printers are designed to mark substrates moving along high-speed production lines. The printer only has a brief moment in which to make its marking before the material is moved along to the next line position. During this time, it's essential that the applied markings do not become smudged or otherwise disfigured as they pass along the line.
For porous substrates (e.g. wood, cardboard, and paper), smudging is less of a concern because the ink can sink below the material’s surface. This sinking effect allows the marking to better retain its shape and legibility. Conversely, codes made on non-porous substrates (e.g. plastics, metals, glass, etc.) are more liable to lose legibility due to the material’s inability to absorb the ink. In addition, many traditional ink formulas (such as water-based inks) do not adhere well to non-porous materials in general, further compounding the risk of code smudging.
Because MEK is a quick-drying compound, markings made with MEK-based ink can better retain their shapes on non-porous materials as compared to water-based inks. Once the solvent evaporates, the pigment, dye, or resin within the formula remains on the material, leaving a sharp, highly readable marking.
MEK-based inks also feature better surface adhesion to non-porous materials than water-based inks, making them a great fit for a wide array of industrial marking applications.
Due to their quick-drying properties and compatibility with non-porous inks, MEK-based formulas are widely used in a variety of industrial marking contexts. Frequently used in conjunction with continuous inkjet printers (and to a lesser extent, thermal inkjet printers), MEK-based inks are used to mark:
The markings made on these materials most frequently take the shape of variable data markings and traceable codes, such as:
When these markings are properly applied, companies can ensure that their products are in line with federal labeling legislation, industry-specific coding standards, and distributor-specified label requirements. Given the importance of code compliance, businesses across the packaging industry frequently choose MEK-based inks for their marking applications. Some of the most high-profile industries that use MEK-based formulas include:
Although MEK-based inks are popular in many industries, certain companies are beginning to move away from MEK formulas for a few reasons.
For instance, although MEK isn’t officially classified as a hazardous air pollutant by the Environmental Protection Agency, many countries beyond the U.S. do regulate MEK to certain degrees. For example, many European and Asian countries only allow a very small percentage of MEK in their legally approved ink formulas. Similarly, an array of countries in South America, Europe, and Asia highly restrict MEK handling, as the compound can be used to manufacture illicit substances. In these countries, officials require licenses from those who handle and possess the chemical.
Finally, some companies simply find that MEK-based inks smell too strongly to use (if you’ve ever smelled a dry-erase marker, you’re familiar with the smell of MEK). These businesses prefer other solvent-based formulas that have fainter smells.
Despite these factors, however, MEK-based inks remain one of the best formula choices for a long list of industrial marking applications.
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