“Cloud Point” is the temperature at which a hot melt adhesive becomes cloudy on cooling and is a measure of compatibility of the formula components. Hot Melt Adhesives (HMA) with a lower cloud point normally impart longer open time and better hot tack. A hot melt adhesive possessing a very low cloud point may present a certain degree of undesired surface tack.

Following is the simplest method to determine the cloud point of HMA…(Read Article)

…Although this is a cost free, very simple and subjective test, the repeatability is good and relatively accurate with a careful observation.

If the VA (vinyl acetate) domain of EVA exhibits better compatibility with the incorporated tackifying resins, the blend remains clear for a longer time during cooling and results in a lower value of cloud point. A blend of EVA with high VA content and rosin esters may form transparent HMAs even though they are fully set at room temperature. Normally, a more polar tackifying resin blended with an EVA will present a lower cloud point… More >>

Cloud Point for an EVA-Based Hot Melt Adhesive
- by Pierce Covert, Glue Machinery Corporation