Stockwell Elastometrics
Blog icon  LinkedIn icon  Twitter icon  Facebook 

icon  YouTube icon  Google+ icon  

The Elastomerics Blog by Stockwell Elastomerics

Friday, May 28, 2010

Silicone Rubber and Pressure Sensitive Adhesives - Silicone Adhesive, Acrylic Adhesive or Combination Adhesive (3M 9731) - which is best???

With so many pressure sensitive adhesive (PSA) offerings on the market today, it can be tough to figure out which adhesive is best for a particular application. Since it is not feasible to stock every adhesive, Stockwell Elastomerics has hand picked 20+ adhesive offerings with a well represented cross section of products available from major tape manufacturers. Most pressure sensitive adhesives offered by Stockwell Elastomerics can be applied to any silicone sponge, solid silicone and silicone foam as well as other gasketing products such as Poron urethane foam, Neoprene, etc.

Silicone adhesives are most often specified when working with silicone rubber products or high temperature applications. Contrary to some ingrained industry thinking, acrylic adhesive can be applied to silicone products. Stockwell Elastomerics has several proprietary systems for preparing silicone sheet materials so they will readily accept acrylic adhesives. These systems have been used by Stockwell Elastomerics for over 20 years.

Silicone Adhesive on Silicone Rubber
An advantage of silicone pressure sensitive adhesive is they can be bonded directly onto smooth silicone rubber foam and solid without any surface preparation. Also, silicone PSA’s have a broad operating temperature -73°C to 260°F (-100°F to +500°F). The typical bond strength (to stainless steel) is 30 to 60 oz/in, which is relatively low when compared to acrylics with typical values of 70 – 150+ oz/in. The cost for silicone PSA’s can be 3 to 5 times the cost of acrylics.

Pros:
• Broad operating temperature range
• No material preparation (on smooth silicone rubber)

Cons:• Moderate to low ultimate strength
• Higher cost
• The shelf life is limited – some manufacturers have 90 to 180 days


Example Products:• 3M 9122 (transfer)
DP1001 (double coated)

Combination Adhesive on Silicone Rubber
Combination adhesives are always double coated (or film supported). This means there is a support layer, typically PET, that is adhesive coated on both sides. The support layer is nearly invisible but unlike transfer adhesives they have X Y dimensional stability. With the combination adhesives the support layer is coated on one side with silicone and the opposite side with acrylic. These adhesives were designed for laminating to silicone rubber. The silicone PSA side bonds to silicone rubber, the end user exposes the acrylic side when the release liner is removed. The combination adhesives do not have the same operating temperature as silicone PSA’s due to the PET layer and acrylic adhesive side which reduce the overall temperature range.

Pros:
• No material preparation (smooth silicone rubber)

Cons:
• Moderate to low ultimate bond strength
• Higher cost

Example Products:
3M 9731 (double coated)
• NT1060 (double coated)

Acrylic Adhesive on Silicone Rubber
Stockwell Elastomerics has proprietary technologies that open the door to the vast options of acrylic pressure sensitive adhesive. Acrylic adhesives are available in a wide range of thicknesses and adhesion properties (greater than 200oz/in on stainless steel). Also, a new family of acrylic adhesives have been designed to address adhesion challenges such as bonding to powder coats and low surface energy plastics (3M 300LSE family). Acrylic adhesives have a reduced operating temperature range than silicone PSA’s, with typical operating temperatures of -40°C (-40°F) to 149°C (300°F). There are some grades that can withstand short term exposure of 204°C (400°F).

Pros:
• Wide range of options (thickness, strength, etc…)
• Lower cost
• High ultimate bond strength
• Longer shelf life

Cons:
• Material preparation required (silicone rubber)
• Not recommended for less than -40°F or more than +300°F continuous

Example Products: 
3M 9485
Adchem 256M
3M 467

When working with silicone rubber and pressure sensitive adhesives it is important to understand the adhesive requirements. If the application requires very low or high temperature performance, silicone adhesive should be specified. If the temperature range of a silicone PSA is not required, significant cost savings as well as bonding performance can be gained by specifying an acrylic PSA.

For more information on silicone, combination, and acrylic adhesive offerings on silicone rubber material and sample swatches, please contact Stockwell Elastomerics at 215-335-3005 or visit our website at www.stockwell.com .

Labels: , , , , , , , , , , , ,


posted by Steve Hughes at 1:58 PM

4 Comments:

Blogger jakshadows said...

In researching the best way to bond neoprene to steel pipe, I found this blog and this post. I've been considering a couple of 3M's products, but I'm still unsure. Is there a "best way"? I'm making climbing poles so the bond must be permanent for safety reasons.

< $BlogCommentDateTime$>  
Blogger Steve Hughes said...

Hi,

You may want to look into liquid neoprene adhesives. We do not use them here but they seem to bond well to the neoprene. With any adhesive it is very important to clean the surfaces and remove oils and debris. Good luck with your project.

Steve

< $BlogCommentDateTime$>  
Blogger Tim said...

Hello,

I am looking to bond solid silicone sheet to steel that has a textured powdercoat finish. Do you have a PSA recommendation for this type of application?

Thanks
TimH

< $BlogCommentDateTime$>  
Blogger Steve Hughes said...

Tim,

If this is a production part a peel and stick pressure sensitive adhesive (PSA) backed silicone sheet may be the best way to go for throughput. 3M and Adhchem offer adhesives formulated for low surface energy materials such as powder coatings. Stockwell carries 3M 9490LE, 9472LE, 9485 and 6038 which work well. If this is a low volume, one off part, you may want to try a silicone based RTV adhesive.

In both cases, PSA and silicone RTV, the depth of the texture will be a factor. You most likely will need a thicker adhesive for better wet out.

I hope this helps,
Steve

< $BlogCommentDateTime$>  

Post a Comment

<< Home