What is Foam Rubber and How is it Made? The Ultimate Guide to Modern Foam Technology

Feb 24, 2025

What is Foam Rubber? The Fundamental Science

Foam rubber is a versatile material prized for its lightweight structure, energy absorption, and thermal insulation properties. This guide explores its production process while highlighting two high-performance variants: NBR/PVC blends and EPDM-based foam rubber – materials engineered to meet modern industrial demands. Also called cellular rubber, this type of rubber is created by introducing gas bubbles into a polymer matrix, forming a porous structure. This process yields materials with:

Low density (0.02-0.3 g/cm³)
High compressibility, elasticity and flexibility
Energy dissipation capabilities
Thermal/acoustic insulation

Research shows these properties make it ideal for applications ranging from personal protective equipment to automotive seals.

Manufacturing Process

Core Components

Base Components:

Polymeric diol (molecular weight 3000)
Toluene diisocyanate
Specialized catalysts
Water (primary blowing agent)
Silicone oil for cell control

Production Steps

Component Preparation

Precise mixing under controlled conditions
Temperature monitoring (up to 130°C)
Catalyst addition for reaction control

Cell Structure Formation

Gas bubble introduction
Structure stabilization
Density control through processing parameters

Key Insight: The choice of base polymer and processing parameters (temperature, blowing agent type) directly determines the foam's cell structure and performance.

Advanced Foam Technologies

NBR/PVC Blend Foam

This innovative combination offers:

Superior oil and chemical resistance
Enhanced ozone/weather resistance
Temperature resistance up to 120°C
Excellent dimensional stability

Optimized Formula:

Hairui's R&D studies reveal a 60:40 ~ 70:30 NBR/PVC ratio achieves optimal balance between elasticity (NBR) and structural integrity (PVC).

Performance Highlights:

Property	Improvement vs Pure NBR
Tear Strength	+25-40%
Ozone Resistance	3X longer lifespan
Compression Set	15-20% reduction

Technical Breakthrough: Advanced dynamic vulcanization techniques create a "sea-island" microstructure where crosslinked NBR particles disperse in PVC, enhancing mechanical stability.

EPDM-Based Foam

Engineered for demanding applications with:

Temperature Range: -50°C to +150°C operational stability
Weathering Resistance: 10+ years UV exposure without cracking
Low Conductivity: 0.035 W/m·K (ideal for HVAC insulation)

Manufacturing Innovations:

1. Salt-Leaching: Creates uniform pores by dissolving NaCl particles post-curing.

2. Chemical Blowing: Azodicarbonamide decomposes to form nitrogen bubbles.

3. Phase-Change Integration: Paraffin wax additives enable thermal energy storage (TES) capacity.

Case Study: Automotive door seals using EPDM foam show 47% better noise reduction vs traditional rubber.

Manufacturing Advantages

Modern foam rubber production offers:

Processing Benefits:
- Reduced equipment requirements
- Lower energy consumption
- Increased production efficiency
Performance Advantages:
- Enhanced fabric adhesion
- Superior reinforcement capabilities
- Improved insulation characteristics

Quality Control Considerations

Key parameters monitored during production:

Physical Properties:

Density uniformity
Cell structure consistency
Dimensional stability
Surface quality

Performance Metrics:

Compression characteristics
Thermal conductivity
Weather resistance
Chemical stability

Industrial Applications

Primary use sectors include

HVACR Systems:

Thermal insulation
Condensation prevention
Vibration dampening
Sound attenuation

Construction Industry:

Building envelope insulation
Mechanical system protection
Acoustic barriers
Moisture control

Future Developments

The industry continues advancing through:

Manufacturing Innovation:

Enhanced automation systems
Improved quality control
Environmental sustainability
Advanced processing methods

Material Development:

Enhanced performance characteristics
Improved durability
Better environmental compliance
Specialized application formulations

Expert Insights

For optimal application selection:

Consider specific requirements:

Operating temperature range
Chemical exposure conditions
Mechanical stress factors
Environmental conditions

Match material properties:

NBR/PVC for oil/chemical exposure
EPDM for weather/temperature extremes
Custom blends for specialized needs

Conclusion

Foam rubber technology continues evolving, offering improved performance and efficiency for modern industrial applications. Understanding both manufacturing processes and material properties ensures optimal product selection and application success.

Hairui Rubber Commitment

As a leading Chinese rubber supplier, Hairui Rubber is dedicated to delivering foam rubber and elastomer solutions that meet the most demanding industrial requirements. Our expertise transforms technical challenges into innovative opportunities.