roll of 9731 tape
We are an authorized 3M Converter at NEDC. As a result, we work with many of their tape products. These include VHB Tapes, EMI Shielding Tapes, Transfer Tapes, and many others. One of the tapes we work with often is 3M 9731 Double Coated Tape. This tape has the great attribute of having silicone pressure sensitive adhesive on one side, while having acrylic adhesive on the other. The tape is designed for attaching two dissimilar surfaces. For example, a silicone-based elastomer to a steel plate. We will break down the components of the tape because it is important to realize which side is which when utilizing this tape. This tape is made up of 3 components/layers:
Construction of 3M 9731, or 9731RW:
-Acrylic Adhesive Side, Adhesive 350
-Clear PET Carrier
-Silicone Adhesive Side
The Acrylic Side:
This layer of the tape is made of the Adhesive Acrylic 350. This adhesive is a high-performing acrylic adhesive that is 1.6 mil (.0016’’) thick. As an acrylic adhesive, this portion of the tape has excellent temperature, and chemical resistance. This portion of the tape is the side that is meant to bond to other substrates such as steel, aluminum, and other high-surface energy substrates. This layer comes with a 4.2 (.0042’’) thick 58# polycoated kraft release liner.
The Carrier:
This carrier is a 1 mil (.001’’) thick clear PET carrier. This provides stability to the product. The silicone adhesive is bonded to one side, and the acrylic adhesive is bonded to the other.
The Silicone Side:
This silicone pressure sensitive adhesive is a 3 mil (.003’’) thick layer. This layer comes with a fluoropolymer non-silicone coated clear release liner that is 2.9 mil (.0029’’) thick. This is the side that is normally bonded to silicone products such as silicone foam, silicone sponge, and silicone rubber. For a silicone adhesive, this side bonds very well. For example, the peel adhesion on polycarbonate is 42 oz/in.
Do I still need to Prime the Silicone Rubber to Stick to It?
You shouldn’t need to, however I would recommend you do use a primer to ensure that the silicone portion of the tape sticks well to the silicone rubber/silicone foam. Different manufacturers sell numerous silicone rubber primers that work for silicone rubber/foam.
Worker hands holding tablet on blurred warehouse as background
Worker hands holding tablet on blurred warehouse as background
Why Use 3M 9731 Double Coated Tape?
If its still suggested to use a primer on the silicone substrate, why would I use 9731 instead of a standard acrylic? This is for several reasons,
A. The double sided nature of 3M 9731 is unique for a double coated tape. Normally silicone/acrylic double coated tapes are not normally found.
B. While we suggest a primer, first it makes it stick a lot better to the silicone substrate, and second, primers are secondary operations that can be hazardous.
Laminating/Cutting of 3M 9731 Double Coated Tape
NEDC laser-cuts, or die-cuts custom shapes of 3M 9731 Double Coated Tape. However, oftentimes NEDC will laminate this tape to different gasketing materials for ease of our customers assembly. As a result, oftentimes our way of supplying 9731 Double Sided Tape to our customers is through parts such as gaskets, and insulators. 3M 9731 can also be kiss-cut onto a liner
More Information on 3M 9731 or 9731RW
It is also good to note that 9731 comes reverse-wound meaning the way the roll is rolled together is reversed. This is designated by 9731RW, RW for “reverse-wound”. In other words, the silicone adhesive side is on the inside of the roll while the acrylic adhesive side is on the outside of the roll. For more information regarding 3M 9731 Double Sided Tape please contact sales@nedc.com.