Extreme Temperature Concerns With Synthetic Wax

As thermoplastic polymers, hot melt adhesives remain solid at room temperature. Heating a hot melt adhesive that contains a synthetic wax polymer transforms it into a liquid that more effectively bonds to surfaces.  This suggests that high heat isn’t an issue for hot melts.  But in reality, temperature extremes in both directions can be problematic.

Hot melt adhesives are suitable under a variety of temperature conditions.  However, their performance can be impacted by temperature extremes.  Manufacturers can adjust their formulas to account for high temperatures to some degree, but users need to be particular about their applications.

High Temperature Concerns

Even though heat is used to transform a solid adhesive into a liquid for application purposes, the strength of a hot melt adhesive tends to decline as temperature increases.  This is due to chemical changes that impact strength, stiffness, and elasticity.  The higher the temperature, the weaker an adhesive’s bond becomes.

High temperatures can soften adhesive, thus reducing its bonding strength.  Excessive exposure to high heat could even lead to bond failure.  However, manufacturers can produce high-temperature hot melts that are applied at temperatures of up to 450°F.  They are more suitable for applications requiring exceptional heat resistance.

Cold Temperature Concerns

The cold temperature concerns associated with hot melt adhesives have less to do with bonding strength and more to do with stiffness.  Exposure to low temperatures tends to cause a hot melt adhesive to stiffen up.  Though bonding strength isn’t compromised, stiffness reduces flexibility. It also increases brittleness.

Once again, manufacturers can adjust their formulas to accommodate colder temperatures to some degree.  But where prolonged exposure to cold is expected, there may be a better option than a hot melt adhesive.

Choosing the Right Adhesive

It goes without saying that choosing the right hot melt adhesive is crucial.  Temperature considerations are just one of the many things that engineers need to consider.  Humidity is another.  High humidity can inhibit adhesive bonding, making hot melt adhesives more suspect at high temperatures.

A manufacturer’s best bet is to ask for data and specifications on any hot melt product before purchase.  Technical information should include data on temperature resistance in both directions.

Advantages and Disadvantages

Hot melt adhesives are fairly common in modern manufacturing because of their many advantages. Manufacturers can do things with them that are not possible with other types of adhesives.

Here are some of the advantages they offer:

  • Hot melt adhesives improve production speed and efficiency by bonding quickly.
  • They are versatile enough to be deployed with a variety of substrates.
  • Hot melts contain no solvents or VOCs, making them environmentally friendly.
  • They do not require curing, so they are often a more cost-effective option.
Of course, hot melt adhesives also have their disadvantages.  At the top of the list is thermal sensitivity.  As previously discussed, hot melt bond strength can be compromised at higher temperatures.  When working with temperature sensitive substrates, a hot melt adhesive is probably not the best bet.

Hot melt adhesives and synthetic waxes may or may not be resistant to chemical exposure or weathering.  It depends on the specific formulation. When chemical exposure is a risk, only certain hot melts are appropriate.

Synthetic Wax From Trecora

Trecora is extremely proud of the synthetic waxes and polymers we produce and their application to enhance hot melt adhesives.  Our synthetic polymers are ideal for a variety of production needs requiring quick application and cure-free bonding.  We invite you to learn more about them by contacting us at your earliest convenience.

In the meantime, always be aware of hot melt temperature sensitivity.  For applications involving temperature extremes in either direction, there may be a better option then a hot melt adhesive.