Cold flow
Cold flow turns up in 2 fields: adhesives, metallurgy. Here is what it means to the people in each one.
Cold flow in adhesives
Slow flow of a soft adhesive at room temperature under its own weight or light pressure.
Soft PSAs and some hot melts keep moving over time even without heat. Cold flow shows as adhesive oozing from roll edges and die-cut parts, and as stacked rolls or label sheets sticking to each other. It is the flip side of good tack: a softer adhesive grabs faster but flows more. Crosslinking the adhesive or choosing a firmer grade limits it.
"Rolls sat stacked on their sides for a month and cold flow glued the whole pallet together at the edges."
Cold flow in metallurgy
The slow, permanent deformation of a solid material under continuous mechanical stress at ambient temperatures.
Also known as room-temperature creep, this phenomenon occurs when metals with low melting points, like lead or zinc, gradually yield under a constant load well below their yield strength. Unlike standard plastic deformation from a sudden impact, it happens over months or years. Engineers must account for it when designing bolted joints or structural supports using soft alloys, as the material will slowly squeeze out of place.
"You can't use pure lead for that structural bracket because the cold flow will eventually cause the bolts to lose their tension."