Engineered plastics such as ABS, acrylic, polycarbonate, nylon, composites and polyester are very common in manufacturing because they open whole new avenues for designers. Engineered plastics are used for durable assemblies that may need to withstand demanding environments such as industrial usage or weather cycles. They’re low-cost, strong and sturdy, yet they’re also lightweight and can easily be molded into complicated shapes and forms to fit specific design needs. And because these types of plastic have relatively high surface energies, they’re fairly easy for adhesives and tapes to wet out and bond.
Engineered plastics offer more design flexibility than metals for creating complex shapes. They offer unique performance and work well across a wide temperature range. Engineered plastics are very durable, allowing them to be used in applications with exposure to weather and UV and additionally offer good fatigue resistance.
The main benefit of engineered plastics over metals is reduced weight while retaining certain performance properties. Engineered plastics also reduce cost, but it isn’t just the lower cost of the raw materials. Plastics can be molded into complicated shapes without the stamping, drilling, bending or other process costs required for metals. Finally, since those shapes nearly always weigh less than metal, they also cost less to ship.
These are some of the best adhesives and tapes to use for bonding engineered plastics. Learn more about each featured technology using the links below.
With 3M™ VHB™ Tapes you can maintain consistency from sketch to construction, eliminating visible fasteners while quickly and easily creating a long-lasting bond that actually builds strength over time. With the ability to join a variety of materials they provide resilient bonding solutions in just about any design you can dream up.
3M™ Scotch-Weld™ Structural Acrylic Adhesives can improve productivity and performance by providing strong, secure bonds with fast cure times and enhanced aesthetics. 3M™ Structural Acrylic adhesives can provide high impact resistance, low odor and up to an 18-month shelf life with no need for refrigeration.
3M Hot Melt Adhesives are cost-effective and very easy to use, and the adhesive flows well to fill any gaps in rough surfaces. Hot melts are very good for bonding engineered plastics to other substrates and are often used for signs, containers, edge moldings and trim.
Surface energy is a physical property of the material surface that determines whether an adhesive will make intimate contact. On a material with high surface energy, a liquid will spread out or wet the surface; on a material with low surface energy, the liquid will resist flowing and bead up. An adhesive must wet out the substrate to provide a bond. Engineered plastics have relatively high surface energies compared to other plastics and are therefore fairly easy to bond. Some surface preparation may improve the surface energy even further, but for many applications this isn’t necessary.
Each type of plastic has its own specific properties. Here is a brief discussion of the major types and their bonding properties.
Composites are plastic materials comprised of a reinforcing fiber or fabric and a resin. The fiber is typically glass or carbon and the resin is usually polyester or epoxy. Composites provide excellent strength-to-weight ratios, making them ideal for aircraft, electronic circuit boards and high-performance sporting equipment applications. They are typically easy to bond, but it’s important to match the adhesive to both the resin and the specific application requirements.
Strong, tough and transparent, with fairly high temperature resistance, polycarbonate is used in many applications as it is readily extruded, molded or thermoformed. Polycarbonate has a fairly high surface energy but often has a scratch-resistant coating that may complicate adhesive selection.
Common as a fiber and in fabric, nylon is actually a family of strong, tough and temperature resistant materials often used in automotive and electrical components. Nylon has comparatively high surface energy for a plastic, but different types have different bonding requirements and mold-release agents can be a particular concern.
A terpolymer made from acrylonitrile, butadiene and styrene, ABS exhibits good toughness and impact resistance. It’s easily molded and used in a wide variety of consumer goods. ABS is usually easy to bond, but the surface energy varies by grade (different percentages of the three monomers).
Transparent, shatter-resistant and easy to form or cut, PMMA acrylic is widely used as a replacement for glass and is also often used in signs. Acrylic is easy to bond, but a scratch-resistant coating can present challenges.
Most polyurethanes are thermosetting polymers that do not melt when heated, though thermoplastic polyurethanes are available. Urethane is widely used to make foam and rubber products for things like cushions and gasket seals; it is also used to make urethane adhesives, so it is comparatively easy to bond.
Easily formed and widely used as fiber, fabric, film and bottles, polyester is widely used for electrical and electronic components and in the manufacture of composites. Polyester has a comparatively high surface energy, but certain applications have special considerations for bonding, such as gel coat on polyester / fiberglass boat hulls.
Also called vinyl and used in drain pipes, gutters, doors, window frames, siding and credit cards, rigid PVC is relatively easy to bond. Flexible PVC is more difficult to bond and the two are sometimes confused with each other, so it’s important to precisely describe your substrate.
In determining which adhesive will perform best, it is very often helpful to consider the assembly type. The six assembly types shown below have different design characteristics that often determine the best adhesive or tape.
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