When it comes to hotmelt adhesive, the first thing that comes to our mind is hot stick glue. They are very popular with DIY applications thanks to its easy-to-use properties. However, they are not widely used in industrial manufacturing due to insufficient adhesion strength in load bearing applications.
So, what is the type of hotmelt adhesive used in industrial manufacturing?
Polyurethane hot melts are being used more and more in industries from high volume manufacturing to DIY and home repair. This is because PUR hot melts have some amazing characteristics that appeal to a huge set of users. They are non-toxic, quick setting, offer great temperature and weather resistance along with high bonding strength, and are affordable at any volume requirement.
Polyurethane hot melt, commonly called PUR hot melt, is an thermoplastic-based adhesive that exists in solid form under room temperature, is heated and dispensed at a molten state. They offer a quick adhesion because of the cooling down from high application temperature or approx. 140 ° C to room temperature.PUR is also unique because it solidifies through moisture in the air to form a super-strong bond that will not re-melt.
Key properties of PUR hotmelt:
- Good bonding strength with different types of material, including nonporous materials. It works with materials that are different from each other.
- Fast curing, easy to use: no mixing or measuring required
- Tolarate the wide temperature range: effective for indoor and outdoor applications
- Flexible and adapts to different uses: can be set hard or remain rubbery
- Once set, it can be sanded and/or painted, and it will not shrink or curl.
Read more: Considerations to make when choosing a hot melt polyurethane adhesive
Why PUR hotmelt is stronger than traditional hotmelt?
To perform the function of bonding between surfaces, adhesive must undergo the process of state changing, usually form liquid to solid through physical or chemical process.
How does hot stick glue create a bond?
Hot stick glue is melted and dispensed on the desired surface, it then cools down and changes from liquid state to solid state and bond the two surfaces. However, the bond is capable of re-melting around the melting point of the original hot stick glue.
What the differences with PUR hotmelt?
As a hot melt adhesive, PURHM glue is also used in the molten state as hot stick glue, and also forms the bond through the cooling process. However, after sufficient time to fully cure, the glue will no longer melt at its original melting temperature. Practice shows that to re-melt a joint with such PURHM glue will require to use a temperature about twice as high as the original melting temperature. So what is the reason?
In addition to the process of changing the physical state from liquid to solid to form a bond, PURHM glue continues to react with moisture to cure. The result is, a very stable connection thanks to both physical transitions and chemical reactions. This is the answer to the question why PURHM adhesive has greater adhesion strength and durability than traditional hot melt.
Common applications of PUR hotmelt?
Thanks to the above advantages, PURHM are being used more and more in industries.
Versatility is the name of the game when it comes to Product Assembly adhesives. PUR hot melt does the job regardless of how tough your bond substrates are. It adheres to plastics, glass, PVFs, aluminum, stainless steel and other metals.
Most electronic and automated assembly lines benefit from a fast-curing adhesive that doesn’t need drying time or measuring, and bonds regardless of temperature swings or contact with water.
Rapid curing makes this adhesive your go-to in the woodworking shop. Besides, Hot melt technology excels when it comes to window sealants, gaskets, foams, corrugated fabrics, plastics, particle board, and light metal applications.
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