
Hot-melt
headlamp application.
With
so many products to choose from, selecting the proper sealant is crucial.
Choosing the wrong industrial sealant, or applying the correct sealant in the
wrong manner, can have serious consequences. With the eventual application of
your sealant in mind, users should make sure that it has the following
characteristics.

Hot-melt
automated assembly.
1. Stability Over a Wide Temperature Range
Once
fully cured, high-quality sealants perform across a range of temperatures. The
best sealants can withstand temperatures ranging -85° to 599°F (-65° to 315°C).
Select a sealant that functions reliably at temperatures outside its
performance range to accommodate unexpected temperature changes.
2. Weather Resistance and Chemical Stability
UV rays, radiation and
weather can cause low-quality sealants to crack, crumble and become brittle,
compromising the seal over time. Look for sealants with good resistance to
these and other erosive factors. Also, some organic sealants react to
atmospheric pollutants or chemicals much the same way iron reacts with water to
produce rust. Use a sealant that does not readily degrade after prolonged
contact with common elements and industrial chemicals.

Dow
Corning®
HM-2500 Hot-Melt Sealant
3. Good Bond Strength
Good industrial assembly
sealants provide durable adhesion to a variety of industrial materials,
including glass, ceramics, wood masonry and many metals and plastics. A variety
of factors contribute to the bond strength of individual sealants, including
chemical composition, cure type and substrate penetration.
4. Electrical Properties
If
electrical properties are a concern, be aware that some organic sealants are
less suited to applications where they may be exposed to electricity; in such
instances, a high-quality silicone sealant may be a better option.
5. Low Flammability
In fire conditions, some
sealants are more burn resistant than others. Silicone sealants, in particular,
are especially reluctant to burn, and many comply with UL flammability
standards.
Most importantly, make sure you select a sealant that can perform at the
highest temperature you require but also offers a secure and flexible hold at
lower temperatures. When in doubt, consult with a qualified expert.