5 Things to Consider Before Applying Hot Melt Adhesives

While hot melt adhesives come in a variety of types, there are five key factors that impact performance across all of them. Consider these items before applying hot melt adhesives to ensure ideal performance is met:

1. Temperature

When applying a hot melt adhesive, ensure it will sufficiently wet out the substrate. This will enable you to achieve a proper bond between two materials.

To do this, set the hot melt tank temperature so that it is hot enough to lower the adhesive viscosity during application. This will help the adhesive properly flow, so that the substrates can be bonded before the adhesive cools.

2. Add-On Level

The add-on level refers to the amount of adhesive applied to a product. While it can vary based on the application method, it always affects the adhesive cooling rate. Understand the desired add-on level to ensure your hot melt adhesive’s cooling rate is achieved.

3. Compression

When two substrates are bonded together, they undergo compression, or pressure. Be careful to apply the right amount of compression to your substrates to achieve an ideal bond without impacting substrate performance.  

4. Open Time

You’ll also want to consider an adhesive’s open time during application. An adhesive’s open time refers to the length of time needed to achieve a serviceable bond. Factors that affect open time include:

• Temperature
• Substrate
• Amount of adhesive applied

5. Substrates

Think about the substrates you’re bonding together. Their texture and chemistry directly impact adhesive bonding. For example, highly textured substrates allow for more mechanical adhesion, whereas high surface energy substrates aid in wet-out. Understanding the substrates prior to applying the adhesive will help determine:

• Which adhesive to use
• How much adhesive to apply

While these five tips can help you know what to consider when applying hot melt adhesives, choosing the right one can still be a challenge. Contact a Bostik expert to ensure you choose the right one for your application needs.

You can also view this relevant content to better understand hot melt adhesives:

• Hot Melt Adhesives: Application Methods and Variables to Consider
• Hot Melt Adhesives: What They're Made of, How They Work, Their Benefits