Have you ever chosen a gasket adhesive?
Finding gasket adhesives can be a crucial step in the gasket design process, but many people don’t know where to start.
At Strouse, we’re used to working with adhesive gasket material to help our customers build the most efficient sealing solutions. Designing an effective gasket relies on the compatibility of the materials and the design.
This gasket adhesive overview will help you achieve the best sealing design functionality,
GASKET ADHESIVES
Gaskets have the essential responsibility of creating a pressure-tight seal between two surfaces, preventing fluid escape and contamination. They also provide insulation, cushioning, and noise reduction.
Your choice of gasket material depends on factors such as temperature range, pressure range, exposure to corrosives or UV radiation, and industry-specific requirements. It’s also crucial to consider the same factors when choosing a gasket adhesive.
Gasket adhesives are used for designs needing tighter, even more reliable bonds between surfaces. Today, we will review adhesive gasket types to help you find an adhesive that suits your material and design.
What are the Best Adhesive Types for Gaskets?
When it comes to adhesives, there are hundreds of variations, which is why we’ve sorted the best gasket adhesives into different categories. As we go over the different types of gasket adhesives, remember that choosing the right gasket adhesive depends on your application and design.
1. PRESSURE SENSITIVE ADHESIVES (PSAs)
Pressure sensitive adhesive (PSA) tape is a category all engineers should explore because the tapes are easy to use, cost-effective, and can be converted into custom sizes and shapes. PSAs typically come in three formulations that match up with various gasket materials: acrylic, silicone, and rubber-based adhesives.
Most available acrylic, silicone, and rubber gaskets are sold and shipped with a pressure-sensitive adhesive backing. These “peel and stick” gaskets feature double sided backings, with the release liner remaining in place until the gasket is installed.
ACRYLIC BASED
Operating temperature range: -50°F (-46°C) to 350°F (177°C).
Acrylics naturally soften when exposed to heat and harden when cooled, offering a wide temperature range. This allows acrylics to flow under light pressure and adhere to most gasketing materials and surfaces, which is vital when bonding to irregular or rough surfaces.
SILICONE BASED
Silicone adhesives offer the broadest operating temperature range: -80°F (-62°C) to 450°F (232°C).
Silicone-based adhesives adhere well to most surfaces, best to silicone elastomers, yet are also the highest cost.
However, the holding power may not be high enough for non-silicone applications. Standard silicone sealants require a 2 to 24-hour curing time (anaerobic sealants cure in about an hour). Without curing, the seal’s integrity can be compromised.
RUBBER BASED
Operating temperature range: 50°F (10°C) to 150°F (10°C).
Usually available at a lower cost (with lower performance), a rubber-based adhesive is a general-use adhesive that works best on aluminum, bare metal, stainless steel, and non-polar substrates: polyolefins, EPDMs, and silicones.
TYPES OF PSAs
Within PSAs, the three main types are adhesive transfer, double sided, and foam tape, with the most common being VHB.
Each adhesive type offers advantages depending on the project’s purpose, but all three can be pre-applied to gasketing material before it’s cut into custom parts.
ADHESIVE TRANSFER TAPE
With high conformability, initial adhesion, and overall strength, adhesive transfer tape’s liner stays on the gasket until the second substrate is ready. Depending on the exact gasket performance demands, other advantages may be useful:
- Flexibility — Thin (sub one mil) and conformable; bonds to irregular shapes and sizes
- No Carrier — Not limited to the temperature resistance of a carrier
- Low Profile — Easily stacked atop one another if needed
If an optional priming solution is used to help the adhesive transfer tape stick to the gasketing material, these gaskets should be used within a year without a priming solution (note: transportation and storage conditions can affect shelf-life).
DOUBLE SIDED TAPE
A carrier within double sided tape enables the bonding of two similar or completely different substrates (perfect for gaskets). It also provides stability, making the tape more manageable to handle and convert. The carrier’s material may be paper, plastic, foam, or film — depending on what the gasket needs to do — thicknesses can range from a fraction of a millimeter to a thick foam.
VHB TAPES
3M VHB™ tapes are double-sided foam tapes made from high-performance acrylic adhesives.
VHB tape can contour to various shapes, including gaskets. In fact, some VHB tapes are strong enough to replace rubber or foam gaskets because their closed-cell construction creates a watertight barrier between two flat parts. Like transfer and double sided tape, VHB tapes can be cut into custom shapes by a flexible material converter.
2. SPRAY ADHESIVES
Both solvent- and water-based adhesives can be sprayed (or applied with a brush or roll).
Spray adhesives are fast to apply, economical, and can cover irregular shapes. Unfortunately, achieving an even application can be challenging even when using a specialized applicator, which might cause quality concerns.
3. LIQUID ADHESIVES
Because spray and liquid adhesives can be messy, they require specialized application processes.
Liquid adhesives are strong, but the application can be challenging, whether done using an automated machine or manually. Also, gasket processing could be slowed by the adhesive’s curing time (which can usually reach handling strength in 5-30 seconds).
Liquid adhesives, commonly used on rubbers and plastics, come in handy for tight spaces, although they’re more expensive, and dripping glue requires clean-up after application.
In some specialized applications, one-part anaerobic liquid adhesives can be applied between complex metal shapes and cured, completely replacing preformed gaskets.
Finding Gasket Adhesives
Although this article suggests three available adhesive types, choosing the right gasket adhesive isn’t as simple as picking one of three options.
Each type of gasket adhesive has hundreds of products on the market.
The most crucial thing to remember is that it’s not simply choosing an adhesive type, it’s how that adhesive is used. Before you get caught up in investing everything into one material or design, consider testing your gasket design to see how it functions.
Not quite ready to begin testing? In that case, consider diving further into gasketing solutions or reading about the cost of custom gasketing to learn more.
Originally published: May 27, 2021
