Wet versus dry adhesive: calculate consumption from solids content

The purchasing question

The adhesive quantity purchased and the adhesive mass retained in a dried laminate can differ. A dry coat-weight target describes the retained solids. A wet adhesive price must be applied to wet consumption, not directly to that target.

Calculation method

Dry kilograms = area × dry coat weight ÷ 1,000. Wet kilograms = dry kilograms ÷ solids fraction. Cost per m² = dry coat weight ÷ 1,000 ÷ solids fraction × wet adhesive price/kg. Use the solids content of the actual prepared mixture when that is the purchased or consumed basis.

Worked example

For 10,000 m² at 2.5 g/m² dry coat weight, retained adhesive is 25 kg. With an illustrative 40% solids mixture, theoretical wet consumption is 62.5 kg. At €4/kg wet, the cost is €250, or €0.025/m². Pricing only the 25 kg dry mass would understate purchase cost by €150.

This is theoretical consumption before transfer losses, startup and residual mixture. Include those separately on a consistent basis. The result does not establish a suitable coat weight, mixing ratio or processing condition; those inputs come from the approved process.

Checks before using the result

• Convert 40% to a solids fraction of 0.40 in manual arithmetic.
• Match price to wet mixture or component purchasing basis.
• Keep process losses separate from solvent removal.

Common questions