Pressure Sensitive Tape is a great way to make mounting of extruded parts and profiles simple, easy and fast. Weather stripping, decorative trim and seals are examples we can all relate to.
In the past extruded parts like these needed to be fastened with screws, nails or glue. Mounting required tools and took time. It wasn’t fast or easy so pressure sensitive tape was a natural fit. Manufacturers of extruded parts soon found that they could easily apply a double coated tape to their parts. This added value and saved time and money.
Tape manufacturers supply the extrusion market with double coated tapes in almost any width and length. Long length formats such as large pancake rolls and spools help reduce downtime and scrap associated with frequent roll changes.
What tape properties should you look for and why? First consider the extrusion material. Next consider what the extruded part will adhere to. What the end use conditions are and finally look at what’s needed to efficiently run the material through your process or subsequent processes.
Here are a few generalities that will help you figure out what tape you need.
Rubber Adhesives bond quickly and provide a strong initial bond. Rubber adhesives also bond well to other rubber materials along with most plastics and metals. They’re are often more cost effective than other adhesive systems too. Some of the drawbacks of rubber adhesive are they’re not well suited for out door applications where sunlight, temperature variations and moisture resistance are required. In addition rubber adhesive systems can get brittle over time and lose performance.
Acrylic adhesive systems can be formulated to provide a wider range of performance properties and therefore suitable to more applications. Acrylic adhesives have long term performance properties along with good UV resistance, moisture resistance and can withstand wide temperature fluctuations. These properties make acrylic adhesives good for out door applications, high or low temperature applications and chemical resistant applications. Acrylic formulations can be customized for specific requirements. Drawbacks are adhesive takes 24 hours to achieve full performance and are generally higher cost than rubber adhesive.
The greatest feature of silicone adhesives is its ultra high temperature performance. It’s also good for bonding to other silicone materials where other adhesives have difficulty. Drawbacks are high cost, doesn’t perform well in vertical holding applications and will release cleanly from most surfaces which could be an advantage in some applications.
With regard to the tape construction, double coated tapes are the most common for applying to extrusions. They can be easier to cut into small rolls and are better for making narrow width long length rolls or spools. The carrier in the double coated tape adds dimensional stability and often increases the overall strength of the part. The carrier also helps keep the adhesive from flowing and sticking to roll edges. Unsupported transfer tapes can be used in some applications but they don’t provide the dimensional stability and all the benefits that come with it.
All types of carrier materials can be used in double coated tapes which will provide different properties. For example a foam carrier will provide cushioning and gap filling. Polyester films have good heat resistance and provide tensile strength. Tissue carriers are low cost and easy to cut. Polyethylene and Polypropylene are extensible and will conform to bends and corners.
Release liners should be considered also. Paper release liners are the most popular and the most cost effective. However, paper liners are susceptible to moisture resulting in cockling/wrinkling or liner shrinkage/expansion. These defects can result in problems processing and more. Film release liners are great for extrusion applications. They don’t absorb moisture which prevents cockling and allows parts to be stored for long periods. Film liners provide greater strength, are less likely to tear during removal and usually cut cleaner also.
I’ve only hit on a few general tape features to consider so talk to your adhesive tape professional for help in selecting the right tape for your extrusion application.