Conductive Pad, ESD Pad, Conductive Adhesive – Cryogenic Exposure

SE65 is a carbon filled electrically conductive silicone rubber with a durometer of 65 on the Shore “A” scale. SE65 is typically used to dissipate or more specifically ground out static while providing some compliance and cushion. SE65 can be bonded to a conductive surface (aluminum or steel) using Stockwell’s RTV-60-CON which is also a carbon filled silicone based RTV (Room Temperature Vulcanizing). Bonding SE65 with RTV-CON makes a very intimate and strong bond when the surfaces are prepared properly.

Silicone has a general operating temperature ranging from -100 to 500°F (some grades vary). The SE65 has a conservative rating of -65 to 400°F. As a very crude test to see if there would be any deterioration of the SE65, RTV-60-CON or the bond between surfaces, a test piece bonded to aluminum was run thru Stockwell’s cryogenic deflasher, removed and hit with a hammer. The attached video clip shows the machine in idle mode set to -80°F (run mode). The sample was tumbled at -80°F for 60 seconds, removed and hit. There was no indication of bond or material degradation. This was a very crude test but does offer some insight to how well the bond holds up.

Stockwell Elastomerics carries a comprehensive line of ESD and EMI conductive silicone sheets, roll goods and molding compounds. For more information about these products, please call 215-335-3005 or email at service@stockwell.com.

Formex – Thin UL Rated Polypropylene Sheet

Formex GK polypropylene sheet has been engineered to meet electronic equipment requirements. Formex has a high dielectric strength making it a good electrical insulator, does not absorb moisture and is UL listed carrying a UL94 V0 or VTM-0 flame rating.

Over the last few years Stockwell has been laminating Formex to other UL94 rated materials such as HT-800 & BF-1000 silicone foams. Laminations are most often used as either a stiffening layer or as a protective top layer. An example of a stiffening layer would be a thin wall dust gaskets that is flimsy. Adding a thin layer of Fomex between the adhesive layer and rubber creates a stiffening effect which aids in assembly. An example of a protective layer would be a battery pads that will see wearing from installation and removal of the battery. In this case, a layer of Formex polypropylene is bonded to the top of the pad.

Stockwell carries thin grades of Formex, which are available for direct die cut parts, waterjet cutting (may have frayed edges) or as a lamination. Laminations to Poron foam or silicone foam are most common. Pressure Sensitive Adhesive (PSA) backing is also available. For more information regarding Formex polypropylene and other UL rated materials stocked and converted by Stockwell Elastomerics visit http://www.stockwell.com/ or call (215) 335-3005.

BF-2000 Ultra Soft Silicone Foam

Previously called EP-2022, BF-2000 Ultra Soft Silicone Foam (liquid silicone base) has been a nice addition to Stockwell’s line of silicone products. With a typical force deflection of 1.5psi required to deflect the material 25%, it is the softest silicone foam product currently offered by Stockwell. BF2000 has excellent rebound (compression set resistance), a wide operating temperature range, is UV resistant and is UL94 V0 flame rated. These properties lend themselves to cushioning and padding for electronics or dust gaskets. LCD gaskets or touch screen gasket are common applications due to the very low rebound force. Like the vast majority of materials carried by Stockwell, pressure sensitive adhesives (PSA, both acrylic and silicone adhesives) can be applied to one or both sides of the foam.

Also in our Liquid Silicone Foam product line are:

BF-1000 is an Extra Soft Silicone Foam with an open cell structure

HT-870 is a Soft Silicone Foam with an open cell structure

HT-800 is a Medium Silicone Foam with a modified closed cell structure

HT-820 is a Firm Silicone Foam with a modified closed cell structure

HT-840 is an Extra Firm Silicone Foam with a modified closed cell structure

F-12 is similar to BF-1000 except with a fabric finish on one side and slightly courser cell structure

All the above silicon foam products listed are UL94 V0 listed (see specific datasheet for details). For more information on BF-2000 Ultra Soft Silicone Foam or other products offered by Stockwell Elastomerics please contact us at (215) 335-3005 or service@stockwell.com.