Self Adhesive Rubber Pads
Self Adhesive Rubber Pads, are also known as adhesive backed button pad, sticky back rubber pads, or 3M adhesive keypad, which is a sticky keypad that is coated with double sided tape to be adhesive and can bond to different materials.
Double sided tapes can be applied to different rubber pads, like clear silicone, neoprene, EPDM, conductive silicone, nitrile, foam rubber etc.
Backing adhesive for rubber pads is made up of two layers of acrylic adhesive with a sandwiched carrier like tissue or PET film, and a removable paper or PET liner to cover the exposing adhesive.
Adhesive Backed Rubber Pads Advantages
Functions of backed adhesive rubber pads is to make button pad waterproof, dust-proof and non slip. For most waterproof silicone button pad, besides adding the waterproof o ring seal to keypad, backing adhesive can be added to enhance sealing function and prevent water or dust affecting internal electronics on PCB.
Sticky rubber pads can adhere to PCB firmly, so that it also acts as a anti-slip pad.
Common 3M Adhesive Types For Rubber Button Pad
General adhesives used in silicone pads are pressure adhesives (PSA). Options of adhesive should accord to silicone pads working environment and the adhesion to touching surface. Adhesive thickness can be 0.05mm - 2.5mm.
For silicone button pad adhesion, we can choose 3M 9448A, 3M 468MP, 3M 300, 3M 9080. These backing adhesives can resist to solvent, and can work in a wide range of temperature from -40˚C to 90˚C. In addition, they performs well in bonding to high surface energy plastic and metal.
If a membrane switch backside is also painted with light-blocking ink, 3M 9080 adhesive is recommended, because its adhesion is better with black ink.
Clear silicone button cover can be glued with clear PET carrier instead of tissue, just like the following translucent adhesive button cover.
Backing Adhesive Rubber Pad Process
1. Clean the area where silicone rubber pads need to be attached with double-sided tape with toluene or other cleaning surface treating agent.
2. Add diluent in proportion and stir evenly for later use.
3. Apply the treatment agent evenly to the area on the pad that needs to be back glued. After evenly spreading, place the rubber pads in a cool and ventilated place for the treatment agent to dry naturally.
4. After the treating agent is air-dried naturally, apply the double-sided tape to the area where silicone button pad that need to be pasted.
5. Then silicone keypads have been tightly bonded to the double-sided tape.
Will Adhesive Affect Rubber Pads & Keypad Backlight Effect?
Adhesive backed rubber pads backlight will not be affected. Thought the tissue or plastic carrier covered and adhesive will slightly increase the thickness, but the conduction part and led light location area will not be cut without adhesive. So in adhesive keypad production, an additional die-cutting tool is required to cut the adhesive tape into keypad shape.