Why does PU color paste become thicker after being stored for one day?

PU color paste is a pigment solution of polyurethane material, mainly used in coatings, adhesives and other industries. If the PU color paste becomes thicker after being stored for a day, it may be due to the following reasons:

Evaporation: The solvent components in PU color paste may evaporate during storage, causing the color paste to become thick. This may be because the container is not tightly sealed or the storage temperature is high, which causes the solvent to evaporate more quickly.

Reaction solidification: The polymer in the PU color paste may react and solidify during storage, causing the liquid to become viscous. This may be caused by prolonged storage or inappropriate temperature conditions.

In order to prevent the PU color paste from becoming thicker after being stored for a day, you can consider the following methods:

Sealed storage: Store PU color paste in a well-sealed container to prevent solvent evaporation and air contact.

Temperature control: Try to store PU color paste within a suitable temperature range to avoid exposure to high or low temperatures.

Stirring and mixing: Before use, properly stir and mix the PU color paste that has been stored for a long time to restore its original liquid state.

If the PU color paste has become thick, you can try the following methods:

Add solvent: Add appropriate amount of corresponding solvent and stir evenly to restore the color paste to appropriate fluidity.

Heating treatment: Under appropriate conditions, PU color paste can be slightly heated to make it more fluid. But please be careful not to overheat, so as not to affect the performance of the color paste.

Please note that the above suggestions are for reference only. On a case-by-case basis, it is recommended to follow the storage and handling recommendations of the PU colorant supplier to ensure colorant quality and performance.