Are the melting point and softening point of hot melt adhesive particles the same thing? Compare and explain two parameters clearly

Direct answer: It’s not the same thing

Hot melt adhesive granulesThe testing report often mentions “softening point”, but rarely includes “melting point”. The reason is simple: this type of adhesive is mostly an amorphous polymer blend system, without a clear melting point like crystals, only a gradually softening temperature range. The softening point is an engineering index measured by the global method, while the melting point is the physical phase transition temperature. The definitions, measurement methods, and applications of the two are different.

A table to see the differences clearly

Which should be considered when purchasing

Look at the softening point, but don’t mistake it for machine temperature. The softening point of 85 ℃ does not mean that the glue can be applied at 85 ℃ – it just starts to soften, and the actual flow construction often requires 160-180 ℃. The correct approach is to use the softening point to determine the upper limit of the heat resistance of the finished product (such as whether there will be re sticking in the warehouse in summer), and set the melt adhesive tank with the “recommended glue temperature” given by the supplier. Sunlife hot melt adhesive comes with three data points: softening point, melt viscosity, and recommended adhesive range. Guangzhou Sunlife Trading will recommend the brand according to your workshop temperature and equipment type, so you don’t need to repeatedly test the temperature yourself.

Two easily misread places

Firstly, do not directly compare different types of adhesives based on their softening point. The softening point values of EVA and PO systems are similar, but their actual temperature resistance performance may be slightly inferior due to differences in adhesion and crystallization behavior. Secondly, the softening point is not equal to the “upper limit of temperature resistance”. When the finished product is under long-term pressure, it often starts to slowly creep at a temperature lower than the softening point by more than ten degrees. Therefore, in scenarios such as stacking and high-temperature storage, additional data on adhesion or constant temperature maintenance should be requested. Only looking at the softening point can easily lead to optimistic conclusions.

Frequently Asked Questions

Q1: Is the higher the softening point, the more heat-resistant it is?
In terms of direction, but if it is too high, it will become harder and brittle, requiring a higher adhesive temperature. The adhesive packaging for books and magazines is more prone to cracking, so it needs to be balanced according to the scene.

Q2: What does “melting range” refer to in some reports?
That is a description of liquidity, approaching softening behavior, but still not a strict melting point.

Q3: Can the softening point be used to set the machine temperature?
No, it is necessary to combine the melt viscosity and equipment instructions. It is recommended to directly request the brand process card.