Anti-static cleanroom products and methods of making same

#1. Field of the Invention

#This invention relates generally to the prevention of particulate contamination and static-discharge in cleanrooms. More specifically, this invention relates to anti-static products used in “cleanrooms”, semiconductor fabrication plants, pharmaceutical manufacturing facilities, and other applications and environments where extreme cleanliness must be maintained, and to methods for making such products.

#2. Description of the Related Art

#FIG. 1 depicts a scanning electron micrograph (“SEM”) of untreated nylon fibers.

#FIG. 2 depicts a SEM of nylon fibers coated with pyrrole polymer particulates.

#FIG. 3 depicts a SEM of untreated polyester fibers.

#The presently disclosed anti-static cleanroom products provide for the dissipation of static electric charge without degrading their cleanroom qualities. This is achieved by applying conductive polymer particulates onto the insulative surface of the product. Surprisingly, the conductive particulate polymeric coatings, even though in particulate form, do not degrade the cleanroom properties. It has been discovered that such particulates can be formed on the cleanroom product and are not easily removed. Accordingly, such coatings do not provide a significant source of “loose particle” contamination.

#Additionally, it has been found that the particulate coating, even though not covering the entire product with either a uniform or coherent film, provides for increased dissipative qualities. A continuous and coherent coating of the particulates is not required and is, in fact, avoided using the present invention. Furthermore, it has been found that the coating results in relatively uniform surface resistivities in multiple directions.

#The anti-static properties for the wiper are achieved by depositing conductive polymer particles onto the non-conductive fibers that make up the wiper. The polymer particles decrease the resistivity of the wiper from approximately 1014Ω to approximately 108 Ω ohms per square cm. Preferably, the resistivity of the final product is from 105 to 1011Ω. If the resistivity is greater than 1012Ω there will be no charge dissipation. However, if the resistivity is too low (i.e., the wiper is too conductive) harmful sparks can result between a surface and the wiper. Therefore, it is important that the resistivity of the resultant wiper is between about 105 to 1011Ω.