Guidelines for Evaluating the Attenuation of Adhesive Strength after Aging of Hot Melt Adhesive Particles: How to Determine the Need for Adhesive Replacement

Hot melt adhesive granulesThe manifestation of aging

After long-term storage, hot melt adhesive particles may become yellow and brittle, and the bonding strength may decrease, but the degree of attenuation is closely related to the storage conditions. Only by scientifically evaluating the degree of aging can we decide whether to continue using or replace the adhesive, in order to avoid blind scrapping and waste.

Reference data for aging strength attenuation

3 steps to determine whether to replace the adhesive

• 1. Visual inspectionThe rubber particles have obvious yellowing, white powdering on the surface, and particle adhesion and agglomeration – indicating severe oxidation or moisture absorption. It is recommended to scrap them
• 2. Wire drawing testAfter melting a small amount of adhesive particles and drawing them, the wire is short, easy to break, and feels brittle – the bonding strength has significantly decreased
• 3. Actual bonding comparisonParallel bonding test was conducted with new adhesive of the same size, and the peel strength decreased by more than 20%. It is recommended to replace it

Suggestions for extending shelf life

Unopened original bags can be stored in a cool and dry place for 18-24 months; After opening, be sure to seal and store it, and try to use it up within 3 months. Sunlife hot melt adhesive is sealed with double layers of aluminum foil inner liner and woven bag when leaving the factory. Guangzhou Sunlife Trading recommends customers to purchase in batches according to monthly usage, with small batches and multiple frequencies to reduce the risk of aging after opening the bag.

Frequently Asked Questions

• Q: Can the adhesive particles still be used even though the color has darkened but the drawing is normal?
  A: The darkening of color is usually caused by mild thermal oxidation. If the adhesive strength decreases by less than 15%, it can still be used, but it is recommended to consume it first and not store it for a long time.