Polyolefin Elastomer for Footwear Materials: Midsoles, Insoles, and Components

How POE enables lightweight, durable, and comfortable footwear — from running shoes to safety boots

Footwear manufacturers face a constant tension. Consumers want shoes that are lightweight and comfortable, but also durable enough to last. They want cushioning that doesn't pack out after a few months, and they increasingly want materials that are more sustainable than traditional EVA or rubber. Polyolefin elastomer is emerging as a compelling solution — especially for midsole foaming where performance really matters.

We supply POE grades specifically developed for footwear applications, with optimized foam characteristics and processing stability. Here's what POE brings to footwear manufacturing.

Why POE for Footwear: The Performance Case

EVA (ethylene-vinyl acetate) has dominated footwear midsoles for decades. But POE offers some genuine advantages that are driving adoption, especially in performance and outdoor segments:

• Lower density: POE foams can achieve densities of 0.15–0.20 g/cm³ vs. 0.20–0.25 g/cm³ for typical EVA. That translates to lighter shoes — a real selling point for running and hiking footwear.
• Better compression set resistance: POE foam recovers better from repeated compression. The midsole doesn't "pack out" as quickly, maintaining cushioning over the shoe's life.
• Cold temperature flexibility: POE's low glass transition temperature (around −55°C) means the foam stays flexible in cold weather. Important for winter boots and outdoor footwear sold in northern climates.
• No plasticizer migration: Unlike some PVC or TPU formulations, POE doesn't rely on plasticizers that can migrate and cause surface tack or degradation over time.

POE in Footwear: Where It Goes

Different parts of the shoe use POE in different ways:

Foaming POE: Process and Parameters

Most footwear applications use chemically foamed POE — typically using azodicarbonamide (ADCA) or other blowing agents. The process is similar to EVA foaming but with some important differences:

At Chambroad, our G6012 grade for footwear is optimized for consistent foam cell structure and crosslinking response. Batch-to-batch consistency means your foaming parameters stay stable — less scrap, more predictable output.

Formulating for Performance Footwear

Pure POE foam works well, but most footwear formulations include other ingredients to fine-tune properties:

• With EVA: Blending 20–40% POE into EVA improves compression set and cold flexibility while maintaining good processability. Common in mid-range performance shoes.
• With rubber: Adding 10–20% natural or synthetic rubber to POE foam improves abrasion resistance for outsole applications.
• Fillers: Calcium carbonate or talc at 5–15% reduces cost and can improve dimensional stability, though at some sacrifice in weight and flexibility.
• Colorants: POE accepts pigments well. Masterbatch addition at 2–4% achieves consistent color in foam.

Testing and Quality for Footwear Foams

Footwear brands and their manufacturing partners need to verify foam performance. Key tests include:

• Density: Measured per ASTM D3575 or ISO 845. Target depends on application — 0.15 g/cm³ for lightweight running shoes, up to 0.25 g/cm³ for work boots.
• Compression set: ASTM D395 or ISO 1856. Measures permanent deformation after compression. Good POE foams show <15% set after 22 hours at 50% compression.
• Rebound resilience: ASTM D2632 (Bashore). Higher values mean better energy return. POE typically achieves 60–70%.
• Tear strength: Important for durability. POE foams typically show good resistance to propagation of cuts or tears.