Cleanroom gloves are worn throughout the electronic, aerospace, solar, medical device and pharmaceutical industries to protect products from contamination during manufacturing. Nitrile cleanroom gloves are a popular choice. Compared with latex gloves, nitrile gloves offer better abrasion resistance and therefore less particulate shedding. They provide excellent biohazard protection, and can be laundered to deliver the lowest particle and extractable levels.
Particle Levels
Cleanroom gloves, along with other cleanroom garments, are worn to protect the product or process from particle contamination caused by the shedding of human skin. So the gloves themselves should have low airborne and liquid-borne particle contamination. Particulates can arise during the manufacturing process, and glove manufacturers routinely test in order to trace and reduce sources of contamination.
The lowest contamination levels are obtained through multiple rinses in deionized water, followed by drying cycles in HEPA filtered driers. To ensure the gloves stay very clean, they are then sorted and packed in double polyethylene bags in an ISO 5 or 4 cleanroom environment.
Ion Extractables
Ionic extractables are traces of elements that can leach out of a glove and harm the product being manufactured. They include elements such as calcium, chloride, sodium, silicon, sulfites and zinc. The type, mobility and amount of ion extractables can seriously affect the manufacturing process. In the semiconductor industry, ions like sodium can induce conduction and low field breakdown in devices. In disk drive manufacturing, chlorides can cause corrosion.
Testing for inorganic ions present on a glove’s surface include using an ion chromatograph and Couple Plasma, Flame-AA or GF-AA in accordance with ASTM guidelines. It’s important to note that in this stringent test the extractable levels are much higher than ion transfer under normal, dry glove use.
Cleanroom Gloves – Selection Criteria
Cleanroom requirements vary from one manufacturer to another, even within the same industry. When selecting cleanroom gloves, the particle levels should match the cleanroom environment. The extractables should be as low as possible, but taken in consideration with the glove’s overall barrier properties, such as AQL, or pinhole rate. A glove with impressively low extractables, but with a high pinhole rate will not keep the manufacturing environment as clean as a glove with a lower AQL.
What is most important for your cleanroom application (particles, extractables, grip, ergonomics) and why? Share your comments below.
