Adhesives can be strong, heat resistant, low odor, and more. What you need will all depend on your application, but flexibility is one important property you may want to explore more.
Flexibility in Adhesives
Flexibility in adhesives is a relative term depending on the type of adhesive. Some types of adhesives are extremely pliable and can change their form drastically without breaking. Laminating adhesives, for example, can be as flexible as fabric. There are also graphic arts adhesives that are very pliable.
On the other hand, some types of adhesives are designed not to bend or stretch as much. Acrylics tend to fall into this category and be more rigid, but when comparing just acrylics, there are ones that tend to be more flexible or have greater elongation than others.
To determine an adhesive’s elongation, or the ability to increase in length, the adhesive is placed in a machine that will slowly stretch it until it snaps. This machine will measure both the percentage of elongation as well as the amount of force it took to break the adhesive.
When to Use Flexible Adhesives
Adhesives that are flexible have specific uses when this property becomes necessary. Different types of adhesives also have different applications.
In terms of structural adhesives, you may want to choose a more flexible adhesive if the bond is for an application with:
- Big temperature fluctuations
- Substrates that expand and contract regularly
- Exposure to a lot of moisture
- Joint movement
- Exposure to frequent vibrations or knocks
- A unique design
Structural adhesives that are flexible may have better resistance to temperature fluctuations as well as thermal expansion in the substrates. These types of adhesives also tend to be necessary in applications with moving parts when mechanical bonding is not an option.
Altogether, these properties can translate to use in window bonding, automotive displays, sporting goods, trailers, gap filling, and more. If the adhesive chosen isn’t flexible but is used for an application where it should be, it could lead to bond failure.
Some Top Flexible Structural Adhesives
When it comes to structural applications especially, you want a good combination of flexibility and strength. There are a lot of adhesives on the market that claim to be both, but how do you find the right one for you to get the job done? Our adhesive experts want to help. Check out our selection of some of the top flexible structural adhesives available.
3M Scotch-Weld Flexible Acrylic Adhesive DP8625NS
3M DP8625NS has the flexibility of a sealant but the strength and cure speed of an acrylic. It has an incredibly high level of plasticity with an elongation greater than 200%. Along with being a flexible MMA, the adhesive is also low odor, non-sag, and non-flammable. It can be used to bond dissimilar substrates like metals, plastics, and composite materials with minimal surface preparation. It also has a slow set speed.
3M Scotch-Weld Flexible Acrylic Adhesive DP8610NS
This flexible acrylic adhesive has a 200% tensile elongation at break. Because it is such a flexible glue product, it also helps mitigate bond-line read-through so you can use thin, flat substrates in designs. 3M DP8610NS has an open time between 10 to 15 minutes and a time to structural strength between 25 to 35 minutes. It is also low odor and non-flammable.
3M Scotch-Weld Acrylic Adhesive DP8705NS
Another 3M adhesive with a high elongation is the 3M DP8705NS. Not only is it a highly flexible adhesive for its kind, but also it can maintain its structural strength in temperatures as low as -40°F for applications where cold temperature performance is necessary. It has a non-flammable classification and low odor formulation.
Choosing the right adhesive for you involves taking into account the specific application, environment, substrate materials, cost, and more. That is a lot to consider and there are so many adhesives on the market. To help you narrow down your choices, our adhesives experts are here to offer their assistance. Just contact us and one of them will reach out to help you find the best adhesive solution for you.
