How to apply Expandable Microspheres in thermoplastic extrusion
To apply expandable microspheres in thermoplastic extrusion, follow these key steps:
1. Selection of expandable microspheres:
Choose the appropriate expandable microspheres grade based on the processing temperature range. For example, Waytop offers various grades like WP200L and WP200XL for different temperature ranges.
2. Preparation of Thermoplastic Granules:
If using Waytop DU expandable microspheres, wet the thermoplastic granules with mineral oil or plasticizer to achieve a tacky surface for the spheres to attach themselves.
3. Extrusion Process:
– Extruder Selection: Preferably use an extruder with an L/D ratio of ≤ 32. Single screw machines are usually recommended for expanding with expandable microspheres.
– Die and Screw Adjustments: No adjustments to dies or screws are necessary when processing with expandable microspheres.
– Venting Zone: Ensure that the vacuum or venting zone is plugged to prevent poor expansion of the final product.
– Melt Pumps: Avoid using melt pumps as they can destroy the expandable microspheres due to high pressure.
– Residence Time: Control residence time by varying the screw speed to optimize expansion.
– Temperature Control: Gradually increase the temperature from the hopper to the die, with the die temperature having a greater influence on expansion.
4. Effects on Extrusion:
– Melt Strength: The introduction of expandable microspheres can affect melt strength, potentially requiring adjustments in haul-off speed to maintain profile dimensions.
– Calibration/Cooling: Rapid cooling can inhibit some expansion, resulting in a smoother profile surface.
– Co-extrusion: Consider co-extruding with an unfoamed outer layer if a glossy surface is desired.
– Matrix Compatibility: Most thermoplastics with processing temperatures up to approximately 230°C are suitable as a matrix for expandable microspheres.
By following these steps and considering the key factors related to expandable microspheres, thermoplastics, and extrusion, you can effectively incorporate expandable microspheres into your thermoplastic extrusion process.
The key advantages applying expandable microspheres in thermoplastic extrusion
Applying expandable microspheres in thermoplastic extrusion offers several benefits, enhancing the properties and performance of the final product. Here are the key advantages:
1.Lightweighting:
Expandable microspheres can significantly reduce the density of the thermoplastic material, leading to lightweight end products. This is beneficial for applications where weight reduction is crucial, such as in automotive and aerospace industries.
2.Improved Insulation:
The incorporation of expandable microspheres can enhance the thermal and acoustic insulation properties of thermoplastic materials. This is advantageous in applications requiring temperature control or sound dampening.
3.Dimensional Stability:
By adjusting the extrusion process parameters, such as haul-off speed and output from the extruder, expandable microspheres help maintain the dimensional stability of the extruded profiles. This is essential for achieving consistent product dimensions.
4.Surface Quality:
Expandable microspheres can contribute to a smoother surface finish of the extruded profiles, especially when rapid cooling is employed to inhibit excessive expansion. This results in a more aesthetically pleasing final product.
5.Cost Efficiency:
Incorporating expandable microspheres in thermoplastic extrusion can lead to cost savings by reducing material usage due to the lightweighting effect. Additionally, the improved insulation properties may result in energy savings in certain applications.
6.Versatility:
Expandable microspheres are compatible with a wide range of thermoplastic matrices, allowing for versatility in product design and application. They can be used with various thermoplastics like SEBS, SBS, TPU, ABS, PS, PE, PP, TPO, and PVC-P.
Enhanced Performance:
The introduction of expandable microspheres can improve the overall performance of thermoplastic products by providing benefits such as impact resistance, thermal stability, and sound absorption.
For more applications, please check our application sections:
https://www.expandablemicrosphere.com/applications
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