The Hot Melt Slot Die Coating Difference: Learn The Facts

Hold on. Maybe you’ve heard of hot melt (and maybe you haven’t—this isn’t a test). Maybe you’ve heard of slot die coating… and maybe you haven’t. But what about hot melt slot die coating? Where does that fall into the mix? Conversion Technologies International has the answers you’re looking for, and we’re ready to walk you through the capabilities of this technology. The more familiar you are with how slot die coating works, the easier it will be for you to make clear-eyed decisions about manufacturing. And as you move forward, you can’t over-emphasize the importance of knowledge and expertise.

What is the difference between slot die coating and blade coating?

We use slot die coating (not to be confused with HOT melt slot die coating) and blade coating for similar projects. They’re not too dissimilar, but each system has its specific pros and cons. The main difference is that the slot die coating process involves an ink reservoir within the die head. This allows us better control over ink flow when utilizing slot die coating. The slot die coating process continuously spills the “ink” (otherwise known as the solution) over the surface in a controlled manner. We’re better able to determine the thickness of the coating this way.

With blade coating, the blade itself essentially scrapes the solution over the surface. While this can yield solid results, there’s more of an opportunity for error and inconsistencies. This process is entirely dependent on the blade’s precision. If the blade isn’t perfectly precise, you’re likely to find unwanted variations. Additionally, the control provided by slot die coating ensures less waste. You’ll prevent waste, which ultimately saves you both time and money.

These methods also correspond with certain products. Due to the high degree of precision involved, we use slot die coating for products like printed electronics, OLED displays, and solar cells. Typically, blade coating is a better fit for packaging, paper, and textiles. While we always value details, some products simply require more attention than others. 

What is the process of hot melt slot die coating?

There’s the overall method of slot die coating, and the more specific process of hot melt slot die coating. We use slot die coating to apply thin layers of solution onto flat surfaces. As previously mentioned, the slot die head is what really sets the slot die coating technology apart. Because the slot die head allows us to control the amount of solution delivered, we’re able to deliver it continuously. This makes the process more efficient, and often faster than certain alternatives. We can also ensure the adhesive coating thickness is exactly where we want it to be. It’s a more consistent process, a more detail-oriented process, and a more perfect process—in most cases.

Where we can customize slot die coating further is in the solution used. What sets hot melt slot die coating apart is the quality of the solution. As the name suggests, we use hot melt coating—which is to say, a pre-melted material. The melting process lowers the viscosity of the material and makes it more flexible. While it’s not the ideal process for every project, it fits certain substrates better than standard slot die coating.

Usually, we apply hot melt coating to more sensitive materials requiring flexibility. Think packaging involving ceramics and plastics, as well as wood, fabric, and foam. As the hot melt coating cools, it solidifies—but until then, it’s easier to manipulate as needed. Therefore, you get the benefit of a harder coating along with the initial malleability of a softer coating.

What is slot die coating used for?

We’ve covered a few of the product types that typically rely on slot die coating, and more specifically hot melt slot die coating. On a broader level, the main industries currently utilizing this process include:

—Food and beverage. Remember, we want flexibility for food and beverage packaging. Therefore, we typically try to apply the coatings for that packaging in a liquid form. Hot melt slot die coating is perfect for such circumstances.

—Micro-electronics. The smaller the product, the more precise the coating. Enter: slot dies!

—Medical. Think about technology like X-rays (heavily dependent on film). We create many medical devices using extrusion die coating systems.

Conclusion:

Now that you know a little more about hot melt slot die coating, it’s time to take the next step! The best thing you can possibly do is consult with experts—people who’ve done all this before and can advise you. At CTI, we offer third party manufacturing services. However, you don’t have to sign a contract before getting great advice. We’ll walk you through an initial consultation and help you determine whether or not we’re a match for your needs. Plus, you can explore other services we offer, like lamination and roll to roll coating.

Contact us here or call 419-924-5566 for more info. Let’s start today!