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ESD Smock Washing Instructions

We regularly get asked about washing instructions for ESD smocks. Usually, the question is something like "how many times can I wash my smock" before I need to buy a new one? In this article, I briefly summarize the best practices for washing and re-using anything labeled an "anti static" or "ESD" smock.


How should I wash my ESD Smock?

A: Machine Wash Warm. Do Not Bleach. Do Not Add Detergent or Softener. Cool Tumble Dry or Hang. Remove Promptly.

► Surfactants such as laundry detergent and fabric softeners chemically break down the black carbon static shielding fabric woven into ESD smocks and lab coats. Do not add them to wash.

► Built in a grid pattern, the black carbon threading shields nearby electronics from static on your clothes and skin underneath the smock. This is what makes your ESD garment “static shielding”.

Whenever you clean an ESD smock in a washing machine you are degrading the quality of it. Most smocks can be washed about 100 times before you need to buy a new one.

Adding commercial detergents or fabric softeners to the wash will accelerate this degradation. Once areas of the black carbon threading are decomposed the garment is no longer “static shielding”.

ESD Resistance Chart for Smocks, Lab Coats

Is your smock still “static shielding”? Consult the manufacturer’s specifications to find out what your smock’s “ESD Resistance” or “Surface Resistivity” should be.

Then test the smocks by performing a panel-to-panel (also known as resistance top-to-top (RTT)) test using a Surface Resistance Meter Kit.

Why Not Use Detergents? The Chemistry

Chemicals in Laundry Detergent by Compound Interest

Click to Enlarge

Modern commercial detergents contain enzymes, bleaches, surfactants, and builders.

The surfactants in commercial detergents usually include anionic (negatively charged) chemicals: alkyl sulfates, alkyl ethoxylate sulfates and soaps in the ingredient list of your detergent. These can strip the conductive carbon threading of its positive ions leaving it predisposed to carrying negative charges.

These are used to remove oily dirt and stains. However, if you have hard water (water that is full of minerals like calcium and magnesium) non-ionic surfactants are more effective. Non-ionic surfactants have no electrical charge. You’ll find these surfactants listed as ethers of fatty alcohols on the label.

While non-ionic surfactants are generally acceptable, in reality, most commercial detergents include both anionic and nonionic surfactants.

Chlorine bleach should also never be used with these garments. It attacks carbon bonds (which is effective in removing dyes from white clothes or discoloring clothes) which destroy the carbon threading of the garments. Non-chlorine bleaches are those used in “color-safe” commercial bleaches that are activated by contact with oxygen in the water. These are known as oxidizing bleaches: hydrogen peroxide, sodium percarbonate, and sodium perborate. While not as destructive to the carbon threading as chlorine bleach they are alkalines that can remove carbon with repeated use.

Further Reading

“The Chemistry of Stain Removal”, Compound Interest, Accessed 01/16/2018

“Understanding Detergent, Soap, Fabric Softer & Bleach”, The Laundress, Accessed 01/16/2018




 
 

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