TPE Granules Stick Together When Granulating? Three Solutions

1. Reasons for TPE granules to stick together during granulation

The phenomenon of TPE material particles sticking together during granulation may be caused by the following reasons:

01. Oil filling problem

• SEBS absorbs excessive oil. Oil itself is sticky. The larger the proportion of oil, the greater the possibility of precipitation (oil spitting), and it is easy to stick.

• SEBS is not fully absorbed before the oil is added to the filler, causing the filler to absorb oil and cause adhesion.

02. Insufficient particle cooling

• If the pellets are not cooled sufficiently, they are packaged as finished products at a higher temperature, and heat will accumulate in the packaging bag. When the ambient temperature is high, the material is more likely to precipitate oil and agglomerate.

03. Too high molding temperature

• When the molding temperature is too high, the polymer may form a substance with a lower relative molecular weight due to thermal decomposition, resulting in increased material viscosity.

04. Excessive addition of lubricant

• Adding excessive surface lubricant to the TPE mixing system, the excess lubricant will appear on the surface of the material, causing the material to feel sticky.

2. Three ways to solve the problem of TPE granules sticking during granulation

01. Processing technology

• Adjust the screw speed and barrel temperature to ensure that the materials are evenly mixed, the particles are fully melted, and the pellets are fully cooled.

• Use molding processes such as low shear and nitrogen purification to reduce the temperature during the molding process.

• Ensure that the particles are sufficiently cooled after granulation. It is recommended that the surface temperature of the particles be below 30°C before packaging. During the production process, if the cooling water is difficult to cool due to hot weather, ice cubes can be added to the water inlet pool to continuously lower the water temperature and reduce the agglomeration of particles when they exit the die head.

02. Formula

• Add an appropriate amount of external lubricant to avoid excessive addition.

03. Raw materials

• Use high molecular weight, star-shaped structure SEBS, and do not absorb more than 2.5 times the oil. Add fillers after absorbing the oil.

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