Looking for source of silicone contamination in ISO Class 8 Cleanroom

[cjdoggy]

One of my clients does injection molding in a certified ISO class 8 cleanroom. The cleanroom is intended to be silicone-free, but we are finding traces of silicone on some of the parts we are checking for silicone. Does anyone know of places silicone could "hide" in a clean room (like, on disposable gloves, hand sanitizer, certain kinds of plastic bins, etc.)? Could also be silica or silicon--our test doesn't know the difference. We are currently testing clean room garments and gloves to see if they contain traces but so far no luck. Thanks!

 

[Ronen E]

If I'm not mistaken silica can come from beach sand.

 

[John Broomfield]

One of my clients does injection molding in a certified ISO class 8 cleanroom. The cleanroom is intended to be silicone-free, but we are finding traces of silicone on some of the parts we are checking for silicone. Does anyone know of places silicone could "hide" in a clean room (like, on disposable gloves, hand sanitizer, certain kinds of plastic bins, etc.)? Could also be silica or silicon--our test doesn't know the difference. We are currently testing clean room garments and gloves to see if they contain traces but so far no luck. Thanks!

CJ,

Here is a paper on common sources of silicone contamination:

“Common sources of silicone contamination are cosmetics such as hand lotion and mold releases or lubricants on manufacturing equipment. Silicone based adhesives, sealants, or films may be used in the manufactured product so that these uncured silicone materials also will be present in the manufacturing facility. In addition to these uncured silicone materials which can be transferred between manufacturing operations by poor housekeeping, the silicone curing process itself can fail if silicones which cure with the aid of a platinum catalyst are “poisoned” by contaminants such as sulfur or nitrogen containing compounds. Silicone oils also may be added to silicone materials to act as a plasticizing or softening agent, and this silicone oil later can escape the cured polymer matrix. The end result is a potential for non-curable silicone (such as oil) to contaminate hardware during the manufacturing process. The ability of silicone oil to migrate across a surface and spread into a thin, transparent and often invisible film can cause considerable consternation to manufacturing personnel who are working to control sensitive processes.”

- https://smtnet.com/library/files/upload/silicone-contamination.pdf

And another:

Silicone Contamination Part 1

Prevention and Detection of Silicone Contamination Part 2

Please let us know what you find.

John