Common Ingredients in Hot Melt Packaging Adhesives

We sometimes get asked what’s in our hot melts and what role these different raw materials play.
In simple terms, there are four main categories of ingredients in the vast majority of packaging hot melt adhesives:

1. Polymer

2. Wax content (or oil / diluent / plasticiser)

3. Tackifying resin

4. Antioxidant additives

Each of these ingredients serves a distinct purpose — and the way they’re balanced defines everything from setting speed to bond strength, temperature resistance, and clean running.

1. Polymers – The Backbone of the Adhesive

The polymer provides the structure and elasticity of the hot melt. It’s what gives the adhesive its cohesive strength — ensuring that when the glue sets, it doesn’t become brittle or crack under stress. Modern formulations use carefully selected base polymers to achieve the right balance of flexibility, heat resistance, and compatibility with different substrates.

2. Waxes, Oils, and Plasticisers – Controlling Flow and Set Speed

Waxes (or sometimes oils and plasticisers) help to modify the viscosity and open time of the adhesive. In simple terms, they control how quickly the adhesive flows when molten and how fast it sets when cooled. Getting this balance right is critical — too much wax can make a glue brittle, while too little can slow production speeds.

3. Tackifying Resins – Building the Bond

Tackifiers improve the wetting and initial grab of the adhesive. They’re the “stickiness” factor that helps hot melt adhesives form strong bonds with a wide range of packaging materials — from coated boards to films and plastics. The choice of resin type greatly influences adhesion performance, odour, and heat resistance.

4. Antioxidants – Protecting Performance Over Time

Even the best hot melts can degrade when exposed to high temperatures over time. Antioxidant additives help to stabilise the adhesive during processing and storage, preventing discolouration, loss of strength, or gel formation in the tank. They ensure a long shelf life and consistent performance.

Want to know more?

Our Whitepaper: Understanding Hot Melt Formulation – A Guide to Modern Packaging Adhesives takes a deeper look at how these components interact, typical formulation ratios, and how tweaks in chemistry translate into real-world packaging performance.

You’ll discover:

• How polymer type affects bond strength and heat resistance

• The impact of wax ratios on application speed and machine cleanliness

• The science behind low-odour, non-tainting hot melts

• Emerging bio-based and recyclable raw material trends

📩 Download the full whitepaper — simply fill in the form below and we’ll email it straight to your inbox.