When selecting TPR or TR for shoe sole production, we usually talk about hardness, density, color, abrasion resistance and appearance.

But there is another factor that is sometimes overlooked: What type of injection molding machine are you using?

Same Material, Different Machine

In shoe sole production, different types of injection molding machines are used, including rotary machines and vertical injection molding systems.

From our experience, the same TPR/TR material does not always behave exactly the same on different machines.

Some machines provide a relatively forgiving processing window, while others can place higher demands on the material's thermal stability, flow behavior and processing consistency.

This becomes especially noticeable when producing soles with:

  • Fine surface textures
  • Glossy and matte areas
  • Complex mold details
  • Transparent or translucent effects
  • High appearance requirements

Why Does Material Quality Matter?

A good shoe sole compound is not only about hardness or mechanical properties.

During actual production, manufacturers also need:

Stable flow. Stable color. Easy molding. Good demolding. Consistent surface quality.

For some machine configurations, a material with a wider and more stable processing window can make a noticeable difference.

This is also why two TPR/TR materials with similar hardness and physical properties may behave quite differently during production.

The Finished Sole Tells the Story

For fashion footwear, the difference can often be seen directly on the finished sole.

A good TR shoe sole material can reproduce mold details clearly and create attractive surface effects, including a distinct contrast between glossy and matte areas.

But the final result does not depend on the material alone.

It is a combination of:

Material + Machine + Mold + Processing Conditions

A Question for Shoe Sole Manufacturers

This is something we would like to discuss with footwear manufacturers and injection molding specialists:

Have you noticed that the same TPR/TR material performs differently on rotary and vertical injection molding machines?

And when changing machines, which material property becomes more important in your production: thermal stability, flow, demolding or surface appearance?

We would be very interested to hear about your experience.

Contact Longyixing Chemicals to share your experience or discuss TPR/TR material selection for your shoe sole production.