In metal fabrication, glass manufacturing, and component assembly, workers wear 13-gauge knit gloves coated with a liquid polyurethane (PU) layer on the palms and fingers. These gloves are favored because they offer the tactile sensitivity of a bare hand combined with a high coefficient of friction (COF) and excellent abrasion resistance. However, routine industrial laundering is silently destroying the mechanical bond of the PU, leading to catastrophic grip failures and crushed limbs via Hydrolytic Flaking and COF Degradation.
The PU coating is applied to the nylon or polyester knit liner as a liquid emulsion and then heat-cured into a solid elastomer. The grip relies on the high surface tack and microscopic texture of the cured PU.
The fatal error occurs when facilities send these gloves through industrial laundry services that use high-alkaline detergents (pH 10+) and extreme heat drying cycles (above 140°F / 60°C). Polyurethane elastomers, particularly the cost-effective ester-based PU used in most grip gloves, are highly susceptible to alkaline hydrolysis.
The hot, highly alkaline wash water aggressively attacks the ester linkages in the PU polymer backbone. The long, elastic polymer chains undergo rapid chain scission, breaking down into short, brittle segments. The PU coating loses its elastomeric properties and begins to undergo Hydrolytic Flaking.
It turns from a flexible, rubbery film into a brittle, chalky crust that physically delaminates from the nylon knit liner. The worker puts on the freshly laundered gloves, and they look clean and intact. But the microscopic surface texture that provided the grip has been chemically scoured away, replaced by a smooth, glazed, degraded polymer film.
The Coefficient of Friction drops from a safe 0.6 (dry) down to 0.2 or lower. When the worker attempts to lift a heavy, slick steel plate or a smooth glass pane, the degraded PU offers no mechanical interlocking or surface tack. The plate slides effortlessly out of the glove, dropping directly onto the worker's foot or crushing a coworker.
The Maintenance Protocol: PU-coated gloves should ideally be replaced rather than industrially laundered. If laundering is necessary, they must be washed in cold water using mild, pH-neutral detergents. They must never be subjected to industrial drying heat; they must be air-dried. Before each shift, workers should inspect the PU palm. If the coating feels smooth and glassy, if it has a shiny, glazed appearance, or if the PU is flaking off around the fingertips to reveal the white knit liner underneath, the hydrolytic breakdown is complete, the COF is gone, and the gloves must be destroyed.
