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foam, sponge, solid silicone

foam, sponge, solid silicone

At NEDC, we offer an incredibly wide range of materials. High performing materials such as silicone rubber is one of them. The reason for this is because silicone has countless incredible properties. These include great electrical properties, high & low temperature tolerance, great customizability, and they also have an incredible amount of specifications allowed to purchase the material to. Silicone is made in many forms through either solid silicone rubber compounds, or from liquid silicone(LSR). NEDC manufactures gaskets, insulators, cushioning pads vibration dampening and more out of silicone products.

Silicone Rubber Foam

As we discussed in other blogs, silicone foam is manufactured out of liquid silicone that is cast onto a liner, and heat cured. Silicone foam is used in demanding sealing applications that require low compression set along with tough environmental properties. The benefits of silicone foam include a large variety of densities that can be helpful when choosing a gasketing material that will work with the compression available in the application. These materials have a very light feel compared to silicone sponge products. These products come with either smooth skin on both sides, or at least one side. The smooth finish makes these materials great cushioning pads for many applications. Listed below are some of the well known silicone foam rubber products in the industry.

Commercial Silicone Rubber Foam Products

Product(click for datasheet download) Manufacturer Specifications it Meets Specialization CFR 177.2600 complaint
BISCO HT-800 Silicone Foam(Medium) – Smooth Both Sides Rogers Corporation Flame Retardant Yes
BISCO HT-840 Silicone Foam(Very Firm) – Smooth Both Sides Rogers Corporation Flame Retardant Yes
BISCO HT-870 SIlicone Foam(Very Soft) – Smooth Both Sides Rogers Corporation Flame Retardant Yes
BISCO HT-820 Silicone Foam(Firm) -Smooth Both Sides Rogers Corporation Flame Retardant Yes
Norseal F12 Silicone Foam(Very Soft) – Textured One Side Saint Gobain Performance Plastics Flame Retardant Yes
BISCO BF-1000(Extra-Soft) Rogers Corporation Flame Retardant Yes
BISCO-BF-2000(Ultra-Soft) Rogers Corporation Flame Retardant No

Silicone Rubber Sponge

Silicone Sponge is similar to silicone foam, except the silicone sponge is made out of a solid compound that cures differently. This compound is similar to a clay like consistency before curing. Similar to many materials, silicone sponge is made to specifications to ensure a consistent product. Specifications for silicone sponge include: AMS-3195, AMS-3196, ASTM D1056, MIL-R-46089, ASTM D6576, and MIL-R-6130. Silicone sponge materials are available in different softness ranges, allowing for different application fits. Depending on the specification silicone sponge can come anywhere from super-soft to firm. These firmnesses define how hard the material is to deflect during compression. Below are some well known silicone sponge rubber products available in the industry.

Commercial Silicone Sponge Products

Product(click for datasheet download) Manufacturer Specifications it Meets Specialization
R10480M Silicone Sponge Medium Saint Gobain Performance Plastics Capable of meeting MIL-R-6130 Type II, Grade B and Grade C/ASTM D6576 Type 2, Grade B and Grade C/ ASTM D1056 Type 2, Class A and D, AMS 3195 Low Compression Set
R10480S Silicone Sponge Soft Saint Gobain Performance Plastics MIL-R-6130 Type II, Grade B and Grade C/ASTM D6576 Type 2, Grade B and Grade C/ MIL-R-46089/ASTM D1056 Type 2, Class A and D Low Compression Set 
R10470M Silicone Sponge Medium Saint Gobain Performance Plastics Capable of meeting MIL-R-6130 Type II, Grade B and Grade C/ASTM D6576 Type 2, Grade B and Grade C/MIL-R-46089/ASTM D1056 Type 2, Class A and D, AMS-3195 General Purpose
R10470F Silicone Sponge Firm Saint Gobain Performance Plastics Capable of meeting MIL-R-6130 Type II, Grade B and C/ASTM D6576 Type 2, Grade B and C/MIL-R-46089/ ASTM D1056 Type 2, Class A and D, AMS-3196 General Purpose
R10460 Silicone Sponge Medium Saint Gobain Performance Plastics Capable of meeting MIL-R-6130 Type II Grade A, B and C/ASTM D6576 Type 2, Grade A, B and C, AMS-3195 Flame Retardant, UL HBF
R10400 Silicone Sponge Medium Saint Gobain Performance Plastics ASTM D6576 Type 2, Grade B and Grade C/ASTM D1056 Type 2, Class A and D, Grade ⅔, AMS-3195 Flame Retardant, UL 94V0
R10450 Silicone Sponge Medium Saint Gobain Performance Plastics Fiberglass Reinforced
R10404 Silicone Sponge Medium Saint Gobain Performance Plastics Thermally Conductive

Silicone Rubber Solid 

Silicone Solid usually refers to rubber that is not cellular in nature. These silicone gaskets range from incredibly very soft, such as 10A durometer to very hard, such as 90A durometer. Typically silicone rubber solid materials are used for conventional gasketing where enough pressure is available to create a conventional seal. Silicone Rubber Solid materials are the most commonly seen silicone gasket material for NEDC. The reason for this is the level of how much can be customized on one type of gasketing material is nothing but amazing. For example, there are several grades available, ultra-low temperature, high elongation, super-high temperature, high tear strength and more. The standard color of many silicone rubber solid products is rusty-red. The color comes from the iron oxide in the materials. Below are some common silicone rubber solid products that are well known in the industry. 

Commercial Silicone Rubber Solid Products

Product(click for datasheet download) Manufacturer Specifications it Meets Specialization
Norseal CHR 9030-9070(30A-70A durometer) Saint Gobain Performance Plastics A-A-59588 2A/2B Grade 30-70 respectively, AMS-3300 series as applicable General Purpose
HT-6210(10A Durometer) Rogers Corporation Super-Soft
HT-6135(35A) Durometer Rogers Corporation Tight Tolerance
BISCO 1240-1270(40A-70A durometer) Saint Gobain Performance Plastics A-A-59588 2A/2B Grade 40-70 respectively, AMS-3300 series, as applicable General Purpose
BISCO HT-6360(60A durometer) Saint Gobain Performance Plastics UL 94V0, HF-1 Flame Retardant

Medical Grade Silicone Rubber & FDA 21 CFR 177.2600 Silicone Rubber

There are two types of silicone rubber when it comes to purity. There is medical grade silicone rubber, and then there is 21 CFR 177.2600. NEDC can provide both types. 

However, for 21 CFR 177.2600 Silicone Rubber there is extruded silicone sponge, silicone sponge, silicone foam, and silicone rubber materials available for indirect food contact. Typically, the colors for these materials are white, or off-white. For more information on FDA gaskets, please check this blog out.

Electrically Conductive Silicone Rubber Gaskets

As discussed in other posts on EMI Gasketing, silicone rubber is a common binder used in electrically conductive gasketing. It is used often because of its versatility and inert properties.

Common fillers for EMI Gaskets: Ni/C, Carbon, Silver/Nickel, and Silver/Aluminum. 

MIL-DTL-83528 is a military EMI shielding specification that discusses these materials in great detail. These fillers impart electrically conductivity to the silicone gaskets to make them effective for EMI gaskets, grounding pads.

Commercial Electrically Conductive Gasketing materials are available through manufacturers such as Saint Gobain. EC-102 is a carbon loaded silicone rubber that has a mid-range electrical conductivity of 5 ohms-cm. This makes it great for electrostatic discharge. 

Product Manufacturer Specifications it Meets Specialization
MIL-DTL-83528 Type A, B, M, H, K, L, E Designated by DLA(Defense Logistics Agency) MIL-DTL-83528 EMI Shielding for Electronics, Military Grade
Norseal EC-102 Silicone Saint Gobain Performance Plastics High Reliability, Grounding Pads
EC-2130 Silicone Rogers Corporation 110 dBs @ 100MHz Great EMI Shielding

Adhesive Backing

Adhesive Backing on Silicone Rubber materials is available with a number of tapes. Some customers believe that only silicone tape can be applied to silicone products. In some cases, silicone adhesive backing is required due to temperature range – so we apply that upon request, or if the print/drawing requires it. However, converters like NEDC have identified ways to apply acrylic tape backings to silicone rubber products. Common tapes we apply include 3M 9485PC, 3M 9472, 3M 9472LE, 3M 467MP and others. 

Shelf Life of Silicone Gaskets/Pads

One of the common questions we get from customers is “What is the Shelf Life of Silicone?” The short answer is 20 years. However, some of the products above would only be certified to 5 years or less. With that said, many of the silicone rubber products we listed above will be in service beyond many of our lifetimes. Silicone Rubber is a reliable polymer that is used across the industry across many applications for years and years.

Outgassing of SIlicone Rubber Products

Outgassing of Silicone Rubber Products is always a concern for customers when choosing a silicone-based product. The reason for this is because silicone rubber outgassing in the industry is a well-known phenomenon that can be detrimental to applications. However, when buying/choosing products for bigger manufacturers, outgassing data is available in many cases. Upon request, NEDC has much of the above on file for customers to evaluate if need be. 

Forms of Silicone Rubber Products

Sponge, Foam, and Solid Silicone Rubber can be provided in many forms. There are silicone sheeting that can be molded, there is silicone calendered goods that are manufactured on a calendar into rolled goods. In addition, there are silicone rubber extrusions. These are manufactured out of a giant play-a-doo machine into a cured finished elastomeric piece. Typically silicone foam is only provided in a finished roll format however. 

More info..

In addition, NEDC die-cuts, waterjet-cuts, and laser-cuts into custom shapes. Oftentimes these custom shapes are silicone gaskets. For more information on silicone products, or you believe you have an application that could utilize a silicone product, please contact sales@nedc.com

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