Perchloroethylene
Perchloroethylene (PERC) is a widely used solvent in the dry cleaning industry due to its powerful degreasing and stain-removing properties.
How PERC is Used in Dry Cleaning
1. Cleaning Process Overview:
-
Clothes are loaded into a dry cleaning machine, which looks like a large front-loading washer.
-
Instead of water and detergent, PERC is used as the cleaning solvent.
-
The solvent dissolves oil, grease, and organic stains without damaging delicate fabrics like wool, silk, or rayon.
2. Cycle Steps:
-
Wash: PERC is pumped into the drum and circulated through the clothes.
-
Extract: The solvent is drained and extracted via spinning.
-
Dry: Clothes are dried with warm air, and the solvent is collected, condensed, and recycled for reuse.
Why PERC is Preferred (Historically):
-
Powerful cleaning agent for oils and greases
-
Non-flammable, making it safer for industrial use
-
Gentle on fabrics, preventing shrinkage and color fading
-
Recyclable within the machine, reducing waste
What is Perchloroethylene (PERC)?
-
Chemical Name: Tetrachloroethylene
-
Formula: C₂Cl₄
-
Type: Non-flammable, chlorinated solvent
-
Appearance: Colorless liquid with a sweet, ether-like odor
Health & Environmental Concerns:
-
Toxic if inhaled in large amounts or over time (linked to liver, kidney, and nervous system effects)
-
Classified as a possible human carcinogen
-
Requires well-ventilated, sealed systems and PPE for operators
-
Strictly regulated in many countries (e.g., banned or phased out in California, EU restrictions)
Alternatives to PERC in Modern Dry Cleaning:
-
Hydrocarbon solvents (less aggressive, more eco-friendly)
-
Liquid CO₂ cleaning
-
Siloxane-based solvents (e.g., GreenEarth®)
-
Professional wet cleaning (water-based with special machines and detergents)
Conclusion:
Perchloroethylene remains effective but is increasingly being replaced due to safety and environmental concerns. Dry cleaners using PERC must comply with strict safety protocols and environmental regulations.