Can hot melt adhesive particles still be used after being dampened? Detailed explanation of judgment methods and remedial measures

hot melt adhesive pelletsWhat should I do if I get damp?

During the rainy season in the south or improper storage in the warehouse, the hot melt adhesive particles may absorb moisture. When damp rubber particles are heated, they will produce a large number of bubbles, overflow, and decrease in adhesion. But not all damp adhesives are scrapped – it depends on the degree of dampness.

Three-step judgment method

• Mild dampnessThe surface of the adhesive particles is slightly wet, with a small amount of bubbles when heated. It can be slowly melted and discharged at a low temperature (120 ° C) before continuing to be used, and the adhesion is basically not affected.
• Moderate moistureThe adhesive particles are visibly soft and adhered, and there are a large number of bubbles and severe overflow when heated. It is recommended to use it for non critical scenarios (such as cardboard box sealing) after drying, and it is not recommended to use it for book and magazine packaging.
• Severe moistureAgglomeration, discoloration, and moldy odor of rubber particles. Irreversible degradation, directly scrapped.

preventive measures

Sealed storage+desiccant is the best solution. Sunlife hot melt adhesive granules are packaged with an inner PE film to prevent moisture. After opening, please transfer them to a sealed bucket and place them in a silicone desiccant. The storage environment should be humid<65%RH。

Frequently Asked Questions (FAQ)

Q: Can the adhesive strength of damp rubber particles be restored after drying?

A: Mild moisture can restore over 90%. The recovery rate of moderate moisture is about 70-80%, and it is not recommended to use it in critical scenarios.

Q: How to determine if the rubber particles are damp?

A: Check the appearance (adhesion/clumping), pinch feel (soft and not brittle), and heat test melting (whether there are a large number of bubbles). The simplest method is to take a few grains and heat them to the working temperature to observe the foaming situation.