Detailed explanation guide for thermal stability indicators of hot melt adhesive particles: Understanding TGA and thermal aging data to select the right adhesive

Why is thermal stability importanthot melt adhesive pelletsThe core indicators?

Heating hot melt adhesive particles in a glue pot for a long time will accelerate the decomposition of products with poor thermal stability, resulting in decreased adhesion, darker color, and increased carbides. Understanding thermal stability indicators is a fundamental skill in selection.

Three core indicators

• 1. TGA (Thermogravimetric Analysis) Initial Decomposition TemperatureCharacterize the temperature at which the colloidal particles begin to thermally decompose. EVA based hot melt adhesive particles typically begin to decompose at 280-320 ° C. The higher the better, but it is not directly related to the operating temperature (170 ° C) – this is a safety margin.
• 2. Thermal aging adhesion retention rateThe ratio of the adhesive force of the glue solution after heating at 180 ° C for 72 hours to the initial value. >85% is excellent,<70%意味着胶液易老化。森莱热熔胶粒标准型号保持率>88%。
• 3. Yellowness IndexThe degree of yellowing of the adhesive after heating. YI value increase<5为良好，>10 indicates insufficient antioxidant capacity in the formula. Directly affecting the appearance of transparent/white adhesive particles.

Frequently Asked Questions (FAQ)

Q: Is there a relationship between thermal stability and opening time?

A: No direct relationship. The opening time is determined by the ratio of thickening agent and wax, and the thermal stability is determined by the base resin and antioxidant. It can achieve long opening time and good thermal stability.

Q: How to determine if the adhesive is aging during daily use?

A: Look at the color and texture. The new glue is light yellow and transparent, while the aged glue is dark yellow or even brown red, and the wire drawing becomes shorter and brittle. It’s time to change the glue when the color is noticeably darker.