5 Hot Melt Problems That Cause Packaging Pop Opens

If you’re involved with end-of-line packaging, chances are you’ve dealt with pop opens.

Pop opens are a fact of life for many manufacturers. They are a symptom of a problem – a problem usually related to the hot melt adhesive being applied. And until that symptom is painful, most manufacturers just learn to live with it.

When pop opens are happening intermittently, plant managers will usually have their team yank the popped-open packages off the line, set them aside, and later seal them up by hand with glue guns. A minor headache.

But when pop opens start happening regularly, causing increased downtime, or worse, they start happening to customers in the field, that’s usually when we get a call.

Our Experience with Pop Opens

We get a lot of calls from companies dealing with pop opens. Troubleshooting hot melt issues is a big part of what we do at

Some companies are looking for a bandaid – a better packaging glue stick and glue gun solution for sealing up popped-open packages. We’ve got some good options there.

Some companies are looking for a better hot melt – something more aggressive, faster setting. We’ve got options there as well.

However, in both cases, before suggesting any new products, we always take a step back to first identify the root of the problem. We love a good hot melt mystery.

What We've Discovered

After years of helping manufacturers troubleshoot pop open issues, we've found that 95% of case and carton pop opens are caused by only a handful of basic hot melt problems. These problems can be relatively simple and inexpensive to fix.

In some cases, fixing the problem only involves some operational changes. In other cases, minor equipment upgrades are all that’s involved. Usually you don’t need a new hot melt or any expensive new equipment.

Below is a list of the most common hot melt problems we’ve found to cause pop opens.

Problem 1: Clogged Equipment Causing Pop Opens

Clogged equipment is the most obvious problem that causes pop opens. If hot melt isn’t being dispensed, cases and cartons certainly aren’t being sealed.

The cause of clogged equipment is usually pretty obvious too: hot melt char

Char starts in the tanks and hoses and eventually works its way down to the filters and nozzles, causing frequent clogs. For some production lines, this means frequent downtime while filters and nozzles are replaced.

Once char has built up in a hot melt system, it’s very difficult to clean out. The best strategy to prevent clogging from char is to prevent char from happening in the first place.

Check out our guide for tips on pinpointing the real sources of char, along with solutions for keeping char out of your hot melt system.

Problem 2: Hot Melt Coverage Causing Pop Opens

The volume and pattern of the hot melt dispensed affects how well it bonds during compression. The wrong volume or wrong pattern can lead to pop opens.

The more common issue is not enough hot melt. Some manufacturers will try to save on adhesive costs by reducing hot melt volume.

However, too much hot melt can be equally problematic, reducing the speed at which the adhesive sets.

Check out our guide for details on how to tell the difference.

Problem 3: Hot Melt Temperature Causing Pop Opens

It’s critical that hot melt is dispensed at the correct temperature, and that the temperature remains consistent. Too high or too low, and you can end up with pop opens.

Running hot melt too hot can cause the adhesive to set too slowly, while running it too cold causes it to set too quickly. Sometimes external factors can cause hot melt temperature to fluctuate, leading to intermittent pop opens.

Our guide goes into more detail on temperature issues.

Problem 4: Substrate Changes Causing Pop Opens

Changes in packaging materials happen more often than you might think. You would hope that packaging manufacturers would notify production teams about these changes, but that’s not always the case.

We’ve witnessed these changes to packaging coatings and fiber content causing sudden, unexplained pop-opens on the line as the hot melt is no longer able to fully penetrate the material.

The guide touches on what to look for here.

Problem 5: Shipping & Storage Temperature Causing Pop Opens

If your company has never had to deal with pop opens in the field, consider yourself lucky. When cases and cartons pop open in the hands of your customers, you can expect some angry complaints and some expensive returns.

Most hot melts have relatively narrow service temperatures. When sealed cases and cartons are stored in hot or cold environments, the adhesive bond can be compromised and eventually fail, leading to a messy situation.

Check out our guide for what to look for here.

The Cost of Pop Opens

In production, the cost of pop opens varies greatly. For some production lines, any amount of downtime means big financial losses. For others, occasional pop opens are just a headache, requiring some extra resources dedicated to sealing up packages by hand.

In the field, the cost of pop opens can be massive. Packaging failures during shipment, or in the hands of a customer, can lead to expensive return shipments, soured relationships, and lasting damage to your company’s reputation.

Fix These Problems Before They Cost You

If you're currently experiencing pop opens in production, are you sure they aren't happening in the field?

We’ve heard enough disaster stories from manufacturers to know how costly these problems can be.

Although we’d be happy to help when things go wrong, we’d rather help you avoid those disasters in the first place. That's why we put together a guide to solving pop opens.

To help you avoid these unnecessary costs, we put together a printable guide that details what to look for along with recommended solutions.

Ready to save yourself and your company some money and headaches? Download the guide.

Guide to Solving Hot Melt Pop-Opens and Case Study

Eliminate Pop Opens For Good

Download our free printable guide to identify and fix the hot melt problems causing your pop-opens.

This guide will help you:

  • Minimize downtime
  • Save on equipment costs
  • Avoid headaches
  • Protect your company’s reputation
Guide to Solving Hot Melt Pop-Opens and Case Study

Eliminate Your Pop Opens For Good

Download our free printable guide to identify and fix the hot melt problems causing your pop-opens.