Polyurethane Adhesive Dry Composite Failure and Treatment

Fault phenomenon

Phenomenon

Solution

Bubbles appear on the composite membrane

The drying tunnel temperature is too low, leaving residual solvent

● Improve the drying tunnel, adjust air volume and wind speed

Solvent moisture content is too high

●Control solvent content is less than 0.2%

Environmental humidity is too high

● Keep the environment ventilated and dry

Composite film wrinkles

Uncoordinated winding or unwinding tension, too big or too small

● Adjust the closing and unwinding tension

Composite roll pressure imbalance or uneven pressure

● Adjust the composite roll to balance it

Composite roller filling or guide roller imbalance

● Adjust the compound roll or adjust the balance of seek roll

Composite film has white spots

Humidity in the environment or the solvent is too high

● Control environment humidity and solvent moisture content

Too much residual solvent

● Increase the temperature of the drying tunnel or slow down the speed

Stirring unevenly when using adhesive

● When mixing, stir well

Excessive amount of curing agent

● Reduce the amount of curing agent

There is still stickiness after the composite film matures

With wrong glue or uneven mixing with glue

● Correctly grasp the use conditions and process of adhesives

Humidity of the environment is too high, the solvent has too high water content

● Control environment humidity and solvent moisture content

Incomplete curing

● Increase the curing temperature or extend the curing time

The quality of the glue itself

● Replace glue

Composite film peel strength is low

Insufficient glue

● increase the concentration of work and replace the roller

Film is damp or corona treated

● Exchange film or corona treatment

Incomplete curing

● Prolong the curing time appropriately

Solvent water content is too high to misalign the base agent with the curing agent

● control solvent water content less than 0.2%

Bags produce odor

Drying temperature is too low, residual solvent is too much

● Improve drying tunnel temperature and increase air flow rate and wind speed

Dilution solvent contains aromatic impurities (toluene, xylene)

● Improve the purity of the solvent

Additive odor in the film

●Change film

The ink is not completely dry during printing.
Residual high-boiling solvents

● Rewind the printed film once through the tunnel

Adhesives contain aromatic solvents

● Replace glue

Low heat seal strength

The quality of the adhesive itself

●Change adhesive

Adhesive curing dose is too small

● increase the amount of curing agent

The humidity is too high or the solvent has too high water content

● Control environment humidity and solvent moisture content

Composite film is not matured

●Prolong the curing time

Source: Huashi Chemicals