How to Choose the Hardness of Footwear Material Granules? What Are the Effects of Materials That Are Too Soft or Too Hard?

In footwear material production, hardness is one of the key indicators that affects sole comfort, support, wear resistance, processing stability, and final product quality.

For slippers, sandals, sports shoes, rain boots, injection-molded soles, and foamed footwear materials, material hardness is not simply about being softer or harder. The right hardness should be selected based on product use, wearing environment, processing technology, and target market requirements.

If the hardness is not properly selected, it may lead to:

Soles that are too soft and lack support
Soles that are too hard and reduce wearing comfort
Finished products that deform or crack easily
Unstable foaming structure
Poor flowability and molding performance during production
Reduced customer experience and product quality

Therefore, choosing the right hardness of footwear material granules is a very important step in footwear product development.

What Does Hardness Mean in Footwear Materials?

The hardness of footwear material granules simply refers to the material’s ability to resist external pressure or deformation.

In the footwear industry, hardness usually affects the following aspects:

Comfort
Resilience
Support
Wear resistance
Anti-slip performance
Molding stability
Service life of the sole

Different types of footwear require different hardness levels. For example, indoor slippers focus more on softness and comfort, work shoes focus more on support and wear resistance, while sports shoes need a balance between cushioning, rebound, and stability.

Why Hardness Selection Matters

The hardness of footwear material granules directly affects the wearing experience and production performance of the final sole.

If the material is too soft, the sole may feel comfortable, but it may lack sufficient support. After long-term use, it may collapse, deform, or wear out more quickly.

If the material is too hard, the sole may provide stronger support, but the foot feel may become stiff, the bending performance may decrease, and the wearer may feel tired more easily.

The right hardness is not determined by a single indicator. It should be evaluated together with the material system, foaming ratio, density, formula stability, and sole structure.

What Happens If the Material Is Too Soft?

1. Insufficient Support

When footwear material granules are too soft, the sole is more likely to show obvious compression deformation under pressure.

For slippers, sandals, or sports shoe midsoles, moderate softness can improve comfort. However, if the material is too soft, the sole cannot provide enough support. After being worn for a long time, problems such as unstable foot feel, collapse, or deformation may occur.

2. The Sole Is Easy to Deform

Materials that are too soft may have poor dimensional stability under high temperature, heavy pressure, or long-term use.

Common problems include:

Deformation at the edge of the sole
Midsole collapse
Unstable bonding between the upper and the sole
Finished products lacking a firm and structured appearance

These issues directly affect the overall quality feel of the shoes.

3. Wear Resistance May Decrease

In some sole applications, materials that are too soft may cause increased friction loss.

Especially for outsoles, outdoor shoes, work shoes, or frequently worn footwear, if the material hardness is too low, the sole surface may wear more easily, affecting service life.

4. Molding Stability May Be Affected

During injection molding, foaming, or compression molding, materials that are too soft may bring certain processing challenges.

For example:

Poor shape retention after demolding
Increased difficulty in controlling product shrinkage
Unclear edges
Reduced surface flatness

Therefore, when choosing footwear material granules, manufacturers should not only pursue a soft foot feel, but also consider mass production stability.

What Happens If the Material Is Too Hard?

1. Reduced Comfort

When the hardness of footwear material granules is too high, the cushioning ability of the sole decreases.

During walking, the impact felt by the foot becomes more obvious. Especially in slippers, casual shoes, children’s shoes, and sports shoe midsoles, overly hard materials reduce wearing comfort.

2. Poorer Flexibility

The sole needs to bend repeatedly during walking. If the material is too hard, the sole will have greater resistance when bending, making the wearer feel stiff.

In some cases, excessive hardness may also increase the risk of cracking during bending, especially in low-temperature environments or under long-term repeated flexing.

3. Anti-slip Performance May Be Affected

The anti-slip performance of a sole is not only related to the tread pattern, but also to material hardness.

If the sole material is too hard, its contact fit with the ground may decrease, which can affect grip. For slippers, sandals, rain boots, and functional shoes, hardness selection needs to balance wear resistance and anti-slip performance.

4. Product Feel and Grade May Decline

A sole that is too hard may give users a stiff, cheap, and uncomfortable feeling.

For footwear products aimed at the daily consumer market, suitable softness and elasticity can often improve product experience and enhance consumers’ perception of product quality.

How to Choose the Right Hardness?

Different footwear products should choose different hardness directions according to their actual use requirements.

1. Slippers and Sandals

These products usually focus more on softness, light weight, and comfort.

Key points to consider include:

Soft foot feel
Lightweight material
Moderate rebound
Stable molded appearance
Good color and surface effect

EVA, PVC, TPR, and other materials can all be used in the production of slippers and sandals. The specific hardness should be adjusted according to product positioning.

2. Sports Shoe Midsoles

Sports shoe midsoles usually need to balance cushioning, rebound, and support.

If the material is too soft, stability during exercise may be insufficient. If it is too hard, the cushioning effect may be affected.

Therefore, sports shoe midsole materials should use footwear material granules with good resilience, low compression deformation, and moderate hardness to improve wearing comfort and sports performance.

3. Rain Boots, Water Shoes, and Injection-Molded Soles

These products require good molding stability, flexibility, water resistance, and durability.

PVC footwear material granules are widely used in rain boots, water shoes, and injection-molded soles. Their hardness, color, softness, and processing flowability can be adjusted according to customer needs, helping factories achieve stable production.

4. Work Shoes and Functional Shoes

Work shoes, safety shoes, outdoor shoes, and similar products usually require better support, wear resistance, anti-slip performance, and durability.

The sole materials for these products should not be too soft. A material system with higher hardness, stable structure, and good wear resistance should be selected.

Our Material Solution: Customized Hardness for Different Footwear Applications

Different customers, different equipment, and different markets have different requirements for the hardness of footwear material granules.

Our company can provide customized material solutions for footwear production according to the customer’s product type and production process, including:

EVA footwear material granules
PVC footwear material granules
Rubber foaming granules
Foamed sole materials
Injection-molded sole materials
Material solutions for slippers, sandals, rain boots, and functional shoes

Our materials can be adjusted according to customer requirements, including:

✔ Hardness adjustment
✔ Color customization
✔ Softness optimization
✔ Improved resilience
✔ Foaming ratio control
✔ Processing flowability optimization
✔ Improved molding stability
✔ Low-odor and environmentally friendly options

We do not only provide a single raw material. Instead, we provide more suitable footwear material granule solutions based on the customer’s product positioning, machine conditions, processing methods, and target market.

Designed for Real Production Conditions

In actual production, material hardness cannot be evaluated separately from factory conditions.

The same footwear material granule may perform differently under different equipment, molds, temperatures, pressures, and foaming processes.

Therefore, in material development and customer service, our company pays more attention to actual mass production performance:

Stable foaming
Easy processing
Reduced trial-and-error cost
Improved finished product consistency
Helping customers control production costs
Improving the overall performance of soles

From sampling to mass production, we can adjust materials according to customer feedback to help customers achieve more stable product performance and better meet market demand.

Applications

Our footwear material granules can be widely used in:

PVC slippers
EVA slippers
Sandal soles
Rain boots and water shoes
Injection-molded soles
Foamed soles
Sports shoe midsoles
Casual shoe soles
Work shoes and functional footwear materials

Whether customers need soft and comfortable materials, lightweight foaming materials, wear-resistant support materials, or injection molding materials, our company can provide corresponding footwear material granule solutions.

Conclusion

The hardness selection of footwear material granules directly affects sole comfort, durability, support, and production stability.

If the material is too soft, it may cause deformation, collapse, and insufficient wear resistance.
If the material is too hard, it may affect comfort, flexibility, and anti-slip performance.

The truly suitable material is not simply softer or harder. It is about finding the right performance balance according to the actual application of the footwear product.

Right hardness. Better comfort. More stable production.

Work with RELYONTECH

Looking for a better alternative to traditional Expanded PVC?

We support footwear manufacturers with customized material solutions and practical formulation guidance.

📩 Contact us for samples & technical support:
salerelyon@gmail.com

🌐 www.relyon-tech.com

About RELYONTECH

RELYONTECH provides one-stop solutions for PVC & EVA compounding and footwear production, helping manufacturers improve product performance, reduce cost, and achieve more stable production.

E-mail: salerelyon@gmail.com

Phone/WhatsApp: +86 15759875789

Address: No;40 7th Qianshan District, Neikeng Town, Jinjiang City, Quanzhou,Fujian, China