Qualifying the correct adhesive tape for a particular application can be a confusing and time-consuming task. This article will provide some guidelines for going through this process and offer key points to focus on.
First, let’s start with some information about adhesive systems. There are three basic adhesive systems used in the pressure-sensitive tape business: rubber, acrylic and silicone. There are many variations of each kind, but for the purposes of this article, we will try to keep things as simple as possible.
- Rubber adhesives are generally fast-grabbing, permanent adhesives with a limited temperature range.
- Acrylic adhesives typically need to be applied for 24 hours to develop their full bond potential. However, acrylic adhesives have a wider temperature range than rubber adhesives. The holding power of acrylic adhesives can vary based on their particular formulation.
- Silicone adhesive systems have the highest temperature resistance and widest temperature range. Silicone also has some unique properties as it is removable from many surfaces; however, silicone adhesives are generally soft and have poor holding power.
Now that you know some of the basics, we can discuss how to select your adhesive system.
- The first thing you need to know is what surfaces will be bonded. As you can imagine, this is a crucial factor in the selection of the correct adhesive tape.
- The next point to consider is whether a permanent or temporary bond is required. Sometimes it can be both. As with double-coated tapes, there can be a permanent bond to one surface and a temporary bond to the second surface.
- Now ask yourself what final product is being produced. This will tell you a lot about the expected service life and service conditions required of the adhesive system. For example, if the finished product is an electrical connector in a car, that implies the item will most likely be shielded from rain and snow, but there will still be wide temperature fluctuations. It also tells us something about the expected longevity needed for the tape.
- Finally, spend some time going over how the tape will be applied and if there are any special requirements needed for the assembly process. Some applications require the tape to be supplied in small, die cut parts or long, spool-wound rolls to accommodate the assembly process, or perhaps the manufacturing process has elevated temperatures that could affect the tape.
Considering all of the above factors is a critical part of the selection process. Once you’ve gathered this information, you have a starting point from which to determine the required adhesive system. Nevertheless, you still need to do a bit more research since adhesive tapes come in all sorts of different constructions such as single side coated, double coated and transfer adhesive tapes (transfer tape is just adhesive cast directly onto a release liner without the carrier film).
So, now the question is which tape construction is best for your application? Here are a few benefits of each:
- Single Side Coated Tapes: These easy-to-handle tapes work best when only one layer of adhesive is required. Sealing a carton is a good general purpose example of this use. Heat shield tapes that are used to secure or tape up insulation are another good example.
- Double Coated Tapes: These tapes are excellent for laminating small parts, die cutting into shapes or slitting to narrow widths. The film or carrier adds dimensional stability. These are also an effective choice when different adhesives are required to bond dissimilar materials.
- Transfer Adhesive Tapes: These act like a double-coated tape, but without the carrier. Transfer tapes are primarily used for laminating to films, foams or other materials. The absence of a carrier aids in wet-out of the adhesive against rough or porous surfaces, thus improving contact to surface area and bond strength. The ability to bond to porous foam is a perfect example of how this works. This construction can also be applied where thickness is a concern.
That brings us to another crucial consideration: tape thickness. Why would it be necessary to have more or less adhesive thickness? In general, it all has to do with the surface to which you’re bonding. A rough or porous surface requires more adhesive to penetrate it and provide a strong bond. A thin adhesive layer may be needed in applications where thickness is a critical requirement or where a strong bond isn’t really necessary, such as with the assembly of cell phones or in a removable tape application.
Finally, keep in mind when selecting your tape backing or carriers that they come in every type imaginable. There are various films, papers, metal foils and fabrics. Listed below are some of the common benefits of each:
- Films: Flexible; available with a variety of properties and temperature ranges; aid in die cutting, abrasion resistance and sealing.
- Paper: Compressible; cost effective and good for die cutting.
- Foils: Generally used in electronic EMI/RFI shielding applications or in heat shielding applications.
- Fabrics: Flexible; provide cushioning; sound deadening; cost effective; and used in medical bandage applications as well as with wire harnesses.
Selecting an adhesive tape can be a daunting challenge if you’re unsure of the specifics of your project. This article’s aim is to offer a basic understanding of the properties to consider when selecting an adhesive tape. We recommend you work with your adhesive tape supplier to find the perfect product for your particular application.