Cleanroom Flexible Packaging

Cleanroom Flexible Packaging

In the past, free floating particles were the principal concern of contamination control. While particles can (and do) come from everywhere; clothing, humans, moving machine parts, poor housekeeping; Most common in-use materials within clean rooms can and do present issues, the use of processing additives and their chemical compatibility can also be of concern when manufacturing bags with multiple layers such as metalized plastics. Ionic contamination, outgassing and non volatile residue (NVR) should also be of concern to those businesses involved in cleanroom manufacturing and cleanroom assembly. Unless the user is aware, the packaging could contribute one or all of these contaminants.

Let's define some terms for a better understanding of the contamination issues:

Particle Contamination: Any material or substance that is unwanted or adversely affects the product.
Sloughing: The process of material shedding particles when flexed. This occurs on all flexible packaging, to a greater or lesser degree, depending upon the softness of the film. Polyethylene sloughs more and larger particles than nylon.
Outgassing: The gaseous material given up by a material or substance.
Non Volatile Residue: Matter or substance that remains on a surface that did not readily vaporize at a relatively low temperature.
Ionic (contamination): Matter that is not electrically neutral but either negatively or positively charged. Typical ionic contaminants are the anions and cations that mainly cause corrosion.
Visibly Clean (VC): The absence of particulate and nonparticulate matter visible to the unaided eye.
Electrostatic Attraction (ESA): The ability of an electrostatically charged surface or object to attract particles (contaminants) of a neutral or opposite polarity to the surface or object.
  1.  Is electrostatic discharge (ESD) a concern when working in cleanrooms? Yes, certainly if the product in production is sensitive to ESD discharge or electrostatic fields.
  2. Have you thought about the potential damage that could be caused by electrostatic attraction (ESA)? All insulative and non-grounded conductive materials have the potential to become electrostatically charged, to either polarity. Will these "electrostatic charged objects" attract contaminants? Yes, they will. When they attract contaminants, the contaminant becomes electrostatically "bonded" to the object. As particle size decreases, electrostatic bond force increases.
  3. Will the cleanliness level of the packaging meet your "cleanliness" of product requirement?
  4. Will the packaging material contribute contaminants when in use to protect your product?
  5. Should you "doublebag?"
  6. What do you want to keep from penetrating the packaging (bag) when it leaves your clean production area: moisture, light, electrostatic discharge energy, air? What do you want to stay in the package: a vacuum, a gas (nitrogen), dry humidity condition? Don't forget the contents --- your product.

Determine what you require, partner with reputable and credible suppliers, work with the supplier to get the best certifiably clean packaging material(s) that will do the job for you, "check it out" personally, and understand and use the appropriate test methods and guidance documents from industry and professional organizations.