Adhesion Matters - Thermally Conductive Adhesives

Episode Date: August 3, 2025

As electronic systems become increasingly compact and component-dense, new designs demand dual function material capability. Traditional mechanical fasteners (screws, clips) are often impractical due to limited space, mechanical stress concerns, weight, or production inefficiencies. Thermally conductive adhesives (TCAs) offer a solution by providing both structural bonding and critical thermal conductivity in a single material. This dual functionality offers numerous benefits, including enhanced design flexibility, long-term reliability, weight reduction, increased production speed and automation, and simplified inventory management. In this episode, we take a deep dive into the various TCA formats (tapes, liquids) and chemistries (silicone, epoxy, acrylic) to suit diverse application needs. The future of TCAs points towards increased multifunctionality, seamless integration with automation, and sustainable formulations, expanding into new applications like 5G infrastructure, data centers, and wearable tech.

Welcome to the deep dive. We're here to unpack the tech that's really shaping things around us. And today we're diving into something fascinating, a challenge that's basically forcing engineers to rethink how we build, well, almost every electronic device you use. Your smartphone, maybe the smartwatch on your wrist, even your laptops power supply, they're shrinking, right? Getting incredibly packed with components. But they're doing more than ever. And this miniaturization, it creates some serious new demands, really tough ones. So our mission in this deep dive, explore how these dual-function materials are becoming absolutely essential. Can't do without them sometimes. And we'll focus specifically on thermally conductive adhesives.

Yeah, it's definitely a critical time for electronic system design. A real turning point. You see it everywhere. Industrial, automotive consumer gear. More functions, smaller spaces. That's the trend. And like you said, this creates a couple of really big hurdles for designers. First, there's always the challenge of heat, thermal control.

heat dissipation. We all know he can kill performance, right? Or shorten the lifespan or just make the device stop working altogether. And then just as important is keeping all those components secure. How do you reliably fix everything in place? Especially with different orientations, tiny spaces. You need that product to last. Right. And traditionally, you know, you've got a hot component needs to connect to a heat sink or the casing. Engineers would typically use screws, maybe clips to hold that thermal material, whatever it is, in between. But it sounds like those old ways screws and clips, they're just not cutting it anymore in these super compact designs. What's really changed? Why are mechanical fasteners suddenly so impractical?

That's a great question. Because it really gets to the heart of why things are changing so fast. A major factor is just space, mechanical clearance. In the latest phones, wearables, things like that, there's often literally no room left for a screwhead or a clip or the tool you'd need. Thermally conductive adhesives, though. They fit the form. They offer much more design flexibility there. Another big driver is reducing mechanical stress. Think about high vibration places, like in cars or aerospace stuff. It heases bond components firmly. Now, unlike, say, thermal pads or gap fillers, which are great for heat transfer, they don't usually provide that structural hold. It heases do both. This really cuts down the risk of things shifting around, which is huge for

long-term reliability. Ah, okay, so they're not just filling a gap for heat. They're actually holding things together. That's a different ballgame. Precisely. And think about weight reduction, too. Critical in aerospace, obviously, or wearables. Every gram counts. Getting rid of screws and clips for an adhesive, it makes the whole assembly lighter. Sometimes it's what makes the product even possible. Yeah, lighter and maybe enabling shapes you couldn't do before.

Exactly. Design freedom. And then there's speed and automation, especially for high-volume manufacturing. Screws need careful alignment, insertion, tightening. It takes time. Adhesives, much faster to apply. And they integrate really well into automated robotic systems. So you get rapid, consistent application, streamlines the whole production line.

Which means faster output, better consistency across millions of units. Huge win operationally. Huge. Oh, and one more thing. Simpler inventory. Instead of stocking tons of different screws, clips, sizes, manufacturers can often rely on just one adhesive solution. Works for various parts, different shapes.

It just simplifies the whole supply chain. Okay, those are really solid reasons for using. adhesives for bonding, especially if you just don't have the room for screws or if you need that production speed makes perfect sense. But you also mentioned it's not just the bonding, right? You still need the thermal side handle, that dual function idea. Yes, that's the key. That's why these materials are, well, such a big deal. They don't just stick things together. They also have that critical thermal conductivity. So they efficiently transfer heat away from sensitive parts to the heat sink or the casing. Think of it like removing a bottleneck. Heat flows more freely than if you

had separate layers for bonding and thermal transfer. You see this need in really demanding electronics, power supplies, LED modules, definitely EV batteries. These applications absolutely need something that can do both jobs, strong bonding and efficient heat removal at the same time. That integrated approach. Wow, sounds really powerful. And how does that affect reliability, especially in, say, tougher environments? That's where they really shine. They're resilience. These adheses are engineered to perform reliably, even with tough conditions. Repeated heating and cooling cycles, constant vibration, even moisture. Makes them perfect for harsh spots like under the hood in a car, aerospace systems, heavy industrial gear.

So choosing a thermally conductive adhesive, it's not just simpler assembly. You're seriously boosting thermal performance and making the whole thing last longer. More reliable. Yeah, I can see the appeal. Dual function simplifies things, better heat management, better reliability. Makes sense. But like any material, there must be different types, different options. Can you walk us through the main formats?

tapes, liquids, how do you choose? Sure. Broadly, yeah, you've got two main formats. Yeah. Tapes and liquids. Thermally conductive adhesive tapes, they come as pressure-sensitive or laminating types. A big plus is they offer both thermal conductivity and electrical isolation. Good insulators. They're also great for joining materials that expand and contract differently with heat. That can be a real headache otherwise. They bond instantly when you apply pressure. And interestingly,

the bond actually gets stronger over time at higher temperatures. Often means you can totally skip the screws or clips, typical uses, attacking heat sinks to GPUs, motor control boards, power converters, things like that. And they come in sheets, rolls. Lots of flexibility for design. Okay, so tapes have clear advantages for speed, maybe that electrical isolation. What about the liquids? Where do they excel? Liquid adhesives are different. They're what we call form-in-place elastomers. They start as a liquid or paste, so they flow into gaps and conform to shapes really well. Then they cure, usually with heat or moisture, into a flexible sort of rubbery solid. This makes them ideal for automated dispensing systems.

Robots can apply them precisely. Because they flow, they're great at filling irregular gaps, ensuring really good surface contact. They're also really good in environments with big temperature swings, hot or cold. Liquids let you vary the thickness easily, and they absorb stress well, which is good in things that vibrate or move. You see them in automotive electronics, telecom gear, computer parts. So the choice.

Tapes often win for quick assembly, electrical isolation. Liquids are usually better for automation, filling complex gaps in flexible bonding and high stress situations. That really helps clarify things. It's always a trade-off, isn't it? Performance, how easy it is to use, reliability, cost. It's always good to have real-world examples. Can you share maybe a couple of cases where these adhesives were clearly the best choice

for a customer? Yeah, absolutely. We've seen some great applications. two recent ones come to mind. One was in the LED lighting industry. They used a pressure sensitive adhesive tape, bond ply, I think it was called, used it to stick LED strips right onto the metal housing, which also acted as the heat sink. The customer needed good thermal transfer, obviously, but also electrical isolation. And importantly, it had to be easy to apply in really high volumes. Using the tape, a pressure sensitive one meant no curing time, no fasteners,

big improvement in assembly speed, efficiency, and result. Faster production, better production, better product, great heat management. So they just peeled and stuck, basically, ditched the screws entirely. Wow, that's a huge simplification. Exactly, huge. Another great example is in electric vehicles, EV batteries. There, a liquid adhesive, liquid bond, was used. Its job was bonding the battery modules to the cooling plates.

Now, the challenge there is massive heat from the batteries. Plus, the surfaces aren't perfectly flat. And you need a super strong, long-lasting bond. The liquid adhesive could flow and conform perfectly to those irregular shapes, and its high thermal performance was crucial. So it provided both the structural bond and the pathway for heat to get to the cooling plate, essential for reliability under really high stress. These materials definitely sound incredibly useful, practical, cost-effective potentially, doing multiple jobs at once.

So I have to ask the obvious question. I'm sure you, our listeners are thinking it too. If they're so great getting rid of fasteners, simplifying inventory, all that design freedom, why wouldn't you use one? What are the downsides? when are they maybe not the best fit? That's a really important question. Because, yeah, no solution is perfect for everything.

They have limitations. A big one is reworkability. Once that adhesive cures, especially the thermosetting ones, it's pretty much permanent. Great for reliability, like we said, but if you need to repair or replace a component later, much, much harder, sometimes impossible without damaging things. Another thing is cure time. Some liquid adhesives need time to set to fully cure. Could be minutes, could be hours.

Unlike, say, a thermal pad you just placed down, that can impact your assembly line speed right at the start. Right. If you need that instant handling strength, that cure time is definitely something to factor in. Definitely. And there's raw thermal performance. While these adhesives are good, very good sometimes. For applications where getting heat out is the absolute number one priority thing, like really high power CPUs, top end GPUs, pushed hard specialized thermal greases, or maybe these change materials might still squeeze out slightly better thermal. connectivity numbers, just pure heat transfer. Cost can be a factor too. Some high-performance

thermal adhesives, they can be more expensive per application than, say, a simple pad or grease. If you're making millions of devices, those pennies add up fast. So budget constraints might point you elsewhere sometimes. And applying liquids especially can require specialized dispensing equipment. You need precision to get even layers. Avoid air bubbles. It adds a bit of complexity. For smaller operations, maybe tapes or pads are just easier to handle. So yeah, it's always a balance. Speed, performance, cost, reworkability. You have to weigh it all for your specific project. That really drives home the point.

Choosing the right material isn't just about picking the highest number on a data sheet. It's a whole evaluation. And speaking of options, let's talk chemistry. You mentioned different types earlier. What are the main chemistries for these adhesives and what are their strengths? Silicones, epoxy. Right. The chemistry is key to the final properties.

We mainly see silicones, epoxy, and acrylics, each has its own strengths. Silicones, for instance, they're known for excellent thermal stability and flexibility. They can handle a really wide temperature range, very hot, very cold. This makes them great for things that see a lot of temperature swings, thermal cycling, or need that flexibility. Okay, so silicone for flexibility and temperature range. What about epoxy's? The poxies generally offer higher bond strength. They create a really tough, rigid bond.

So a structural integrity is paramount. Poxy might be the way to go. You often find them in power electronics, heavy industrial gear. places where they need to withstand heat, chemicals, mechanical stress. But yeah, they are typically more rigid than silicones. So if you need flexibility, maybe not the first choice. Then there are acrylics. These are often used as silicon-free options.

Some applications are sensitive to silicones, maybe delicate electronics or optical components where outgassing tiny gas molecules releasing could be a problem. Acrolics avoid that. They still offer good thermal performance, and they're a great fit for clean rooms where minimizing any contamination is critical. So, yeah, the choice of chemistry, along with the format tape or liquid, it really depends heavily on the specifics.

High temps, vibration, need super strength. That dictates the best match for performance and durability. That's a fantastic breakdown. And it really highlights why getting expert advice for your specific application is so important. It's complex. So, looking ahead now, what's next? What's the future hold for thermally conductive adhesives? Any exciting developments on the horizon?

Well, the future is definitely exciting. things are moving fast. One clear trend is more multifunctionality. Packing even more features into one material. We talked about bonding and thermal, but now customers are asking for electrical insulation, flame retardancy, maybe even vibration damping. All in the same adhesive. EVs are a perfect example driving this. They're moving beyond just using gap fillers. Now, thermally conductive adheses are bonding battery modules, transferring heat, providing structure, making the whole pack lighter, simpler, more efficient thermally. It's a systems approach. That kind of integration, doing more with one material, that's a huge focus. Right. Making the adhesive work harder. Solve more problems at once. Holistic design. Exactly. And automation too. Developing adhesives that work flawlessly with robots for high speed, precise application and mass production. That's ongoing. Sustainability is another big push. Greener formulations, more recyclable options. The industry is definitely working on that. And we're seeing them expand into new areas. 5G infrastructure, huge data centers, advanced wearables, anywhere you need to manage. heat in tiny spaces. That demand is just growing. So, summing it up. The future is about more

functions, better performance, and wider use across more and more technologies. Well, thank you. That was a truly insightful look into these really versatile materials and where they're headed. It's clear just how vital these developments are for so many industries, enabling the kinds of compact, powerful devices we all rely on. And for you, our listener, think about this. As our world keeps demanding more power from smaller packages, how might these hidden materials, these multitaskers, fundamentally change the tech you use every day, and what other material innovations might be quietly working behind the scenes, just waiting to enable the next big leap.

Something to consider about the silent workhorses driving our technological progress. Thanks for joining us on the deep dive.