Silicone Foam vs PU Foam vs PORON: How Core Materials Affect Conductive Foam Performance

2. Performance Comparison of Three Core Materials

The core material determines how a conductive foam performs under mechanical stress, temperature changes, and long-term compression.

While the conductive fabric provides the electrical pathway for EMI protection, the foam core maintains the contact pressure needed for stable grounding. In practical emi shielding foam applications, both electrical and mechanical performance must be considered together.

Silicone Foam vs PU Foam vs PORON Comparison

For compression recovery and permanent deformation testing methods, material selection should be evaluated based on actual working conditions rather than only initial softness.

3. How Core Materials Affect Conductive Foam Performance

The foam core is not an independent component. It works together with the conductive fabric, adhesive layer, and structural design to determine the final performance of conductive foam gaskets.

3.1 Effect on Compression Force

The density and elasticity of the foam core directly affect compression force.

Under the same 30% compression condition:

For applications requiring extremely low pressure, such as display module shielding, softer structures are preferred.

This is why solutions like AIR LOOP are often used instead of silicone foam in ultra-thin displays. Silicone foam provides excellent durability but may generate excessive pressure on sensitive components.

AIR LOOP adopts a hollow structure to reduce compression force while maintaining reliable grounding performance. Its compression force can be significantly lower than traditional FOF structures, making it suitable for pressure-sensitive applications.

You can learn more about low-pressure shielding design here:
Low Pressure Conductive Foam Design for Display Shielding

3.2 Effect on Temperature Resistance

Temperature resistance is one of the most important factors when selecting an emi shielding foam material.

A high-temperature conductive fabric cannot compensate for a low-temperature-resistant foam core.

For example:

• PU foam may lose elasticity after prolonged high-temperature exposure.
• PORON provides better stability but remains a polyurethane-based material.
• Silicone foam maintains mechanical properties under much higher temperatures.

This is why SMT conductive foam applications require silicone-based cores.

During SMT reflow soldering, peak temperatures can reach approximately 260°C. PU and PORON materials cannot withstand this thermal process, while silicone foam can maintain structural integrity.

For more details about SMT foam structures and material selection, see:

SMT Conductive Foam Gasket Structure Guide

3.3 Effect on Long-Term Reliability

The service life of conductive foam depends heavily on compression set performance.

Compression set refers to the permanent deformation that remains after the foam is compressed for a long period.

A lower compression set means:

• More stable contact pressure
• More reliable grounding
• Longer shielding life

Silicone foam generally provides the best long-term stability, especially in environments involving:

• High temperature
• Thermal cycling
• Outdoor exposure
• Automotive electronics

This is why silicone-based conductive foam gaskets are widely used in applications where reliability is more important than initial cost.

3.4 Effect on Cost

The foam core can represent a significant portion of the total conductive foam cost.

For standard FOF conductive foam:

• Foam core cost usually accounts for approximately 30–50% of total material cost.

For SMT conductive foam:

• Silicone core materials and conductive PI film structures contribute a larger percentage of the cost.

Material selection should always balance:

• Required reliability
• Operating environment
• Product lifetime
• Manufacturing process
• Cost target

Choosing the cheapest foam core may reduce initial BOM cost but increase failure risk during reliability testing.

4. How to Select the Right Foam Core by Application

Different applications require different material priorities.

Application 1: Standard Consumer Electronics

(Smartphones, tablets, standard laptops)

Recommended material:
PU foam or PORON

Why:

• Normal operating temperatures are usually within 0–50°C
• Cost efficiency is important
• Low compression force is preferred

Selection tip:

If the product must pass high-temperature aging tests such as 85°C aging, evaluate whether PU foam can maintain sufficient rebound performance.

Application 2: Premium Consumer Electronics

(Flagship smartphones, high-end laptops)

Recommended material:
PORON

Why:

• Higher dimensional accuracy
• Better batch consistency
• Lower compression set
• More stable EMI grounding performance

Although PORON costs more than PU foam, the material cost impact is usually small compared with the overall BOM of premium devices.

Application 3: Automotive Electronics

(EV systems, BMS, cockpit electronics)

Recommended material:
Silicone foam

Why:

Automotive electronics typically require:

• -40°C to 125°C operation
• Long service life
• Thermal shock resistance
• Stable mechanical performance

PU and PORON may not meet these requirements in harsh environments.

For automotive PCB shielding requirements, you can also refer to:

Automotive PCB EMI Shielding Foam Requirements

Application 4: SMT Reflow Process

Recommended material:
Silicone foam or silicone extrusion

Why:

SMT conductive foam must survive:

• Peak reflow temperatures around 260°C
• Automated assembly processes
• Long-term solder joint reliability

Only silicone-based cores can meet these thermal requirements.

Application 5: Display and Screen Shielding

Recommended material:

• PU foam with special structure
• AIR LOOP hollow conductive foam

Why:

Display modules are extremely sensitive to pressure.

Excessive compression force may cause:

• Display pressure marks
• Mura defects
• Mechanical stress

For ultra-thin displays, hollow low-pressure structures are often better than traditional foam cores.

Application 6: Outdoor Communication Equipment

Recommended material:
Silicone foam

Why:

Outdoor equipment requires resistance against:

• UV exposure
• Ozone
• Humidity
• Temperature cycling

Silicone foam provides much better environmental durability than polyurethane-based materials.

5. Conductive Foam Core Material Selection Decision Tree

Choosing the correct core material for conductive foam should be based on the actual application environment, manufacturing process, and reliability requirements.

There is no universal “best” foam core. The correct choice depends on operating temperature, compression requirements, precision requirements, and cost targets.

Step 1: Does the product go through SMT reflow soldering?

Yes → Choose silicone core

Reason:

• Reflow temperature can reach around 260°C
• PU foam and PORON cannot withstand this process
• Silicone foam maintains structural stability

Typical application:

• SMT conductive foam gaskets
• PCB grounding components
• Electronic modules requiring automated assembly

No → Continue to Step 2

Step 2: Is the working temperature above 85°C?

Yes → Choose silicone foam

Reason:

Silicone provides:

• High-temperature resistance
• Better aging performance
• Lower compression set

Typical applications:

• Automotive electronics
• Industrial equipment
• Outdoor communication systems

No → Continue to Step 3

Step 3: Does the application require extremely tight dimensional control?

Yes → Choose PORON

Recommended when:

• Thickness tolerance needs to approach ±0.1 mm
• Product consistency is critical
• Premium consumer electronics are involved

Typical applications:

• Smartphones
• High-end laptops
• Precision EMI shielding components

No → Continue to Step 4

Step 4: Is cost sensitivity the primary concern?

Yes → Choose PU foam

Advantages:

• Lowest material cost
• Easy processing
• Flexible customization

Typical applications:

• General consumer electronics
• Standard grounding applications

No → Choose PU foam or PORON based on precision requirements

6. Konlida’s Conductive Foam Core Material Selection Experience

Konlida provides complete material solutions from conductive fabrics and conductive PI films to foam core materials.

Instead of selecting materials only based on specifications, our engineering team evaluates:

• Compression requirements
• Temperature conditions
• Reliability targets
• Assembly process
• Product lifetime

to recommend the most suitable emi shielding foam solution.

Complete Core Material Capability

Case Study 1: Tablet Grounding Failure Caused by Incorrect Foam Core

A consumer electronics customer originally used PU-core FOF foam for motherboard grounding.

During the 85°C / 85%RH double-85 reliability test, the rebound rate dropped to around 70%, causing grounding resistance to exceed the specification.

Konlida recommended replacing the PU core with PORON.

Result:

• Rebound rate increased to approximately 93%
• Grounding performance passed testing
• Project delay risk was avoided

The lesson:

A higher-performance conductive fabric cannot compensate for an unsuitable foam core.

Case Study 2: Automotive BMS Shielding Requirement

A Tier 1 automotive customer required:

• Operating temperature: -40°C to 125°C
• 1,000 thermal shock cycles
• Rebound rate above 90%

Neither PU foam nor PORON could satisfy the reliability requirement.

Konlida recommended:

• Silicone foam core
• Gold-plated conductive PI film structure

After 1,000 thermal cycles:

• Rebound rate remained around 92%
• Reliability testing passed

This demonstrates why silicone-based conductive foam gaskets are preferred for automotive applications.

Case Study 3: Laptop Display EMI Shielding

A laptop manufacturer was concerned that traditional conductive foam would create excessive pressure on the display module and cause Mura defects.

Konlida recommended the AIR LOOP hollow structure.

Advantages:

• No traditional foam core required
• Ultra-low compression force
• Maintains reliable grounding
• Protects display quality

The result:

• Display performance maintained
• EMI shielding requirements achieved

This case highlights an important design principle:

Material selection must match the working condition. There is no universal foam core—only the right foam core for each application.

7. Frequently Asked Questions About Conductive Foam Core Materials

Q1: Are PU foam and PORON basically the same material?

Answer:

Both are polyurethane-based materials, but their manufacturing processes and internal structures are different.

PORON uses a more controlled microcellular structure, providing:

• Better consistency
• Higher dimensional accuracy
• Improved rebound performance

It can be considered a higher-performance version of polyurethane foam, with a higher cost.

Q2: Can silicone foam become as soft as PU foam?

Answer:

Generally, no.

Silicone naturally has higher hardness than polyurethane. Even after foaming and reducing density, silicone foam usually maintains higher compression force than PU foam with the same density.

For ultra-low-pressure applications, such as display shielding, AIR LOOP hollow structures may be a better solution.

Q3: Why do SMT conductive foam gaskets require silicone cores?

Answer:

Because SMT conductive foam must survive reflow soldering temperatures around 260°C.

PU foam and PORON will soften, melt, or permanently lose their properties at this temperature.

Silicone foam can withstand high-temperature processing and maintain mechanical reliability.

Q4: How can engineers evaluate foam core quality from suppliers?

Answer:

The most important parameters include:

1. Thickness tolerance
2. Rebound rate before and after aging tests
3. Compression permanent deformation
4. Batch-to-batch consistency

Reliable suppliers should provide actual test data rather than only theoretical specifications.

Q5: Can PU foam, PORON, and silicone foam replace each other?

Answer:

In standard FOF conductive foam structures, these materials may sometimes be interchangeable depending on size and requirements.

However, performance will change.

Examples:

• SMT conductive foam → silicone core only
• AIR LOOP → usually hollow structure without traditional foam core
• High-temperature applications → silicone preferred

Material replacement should always be evaluated according to the specific application environment.

About Konlida

Konlida Precision Technology is a high-tech manufacturer specializing in EMI shielding materials and thermal management solutions.

Established in 2006, Konlida focuses on the research, development, and manufacturing of advanced shielding materials for consumer electronics, automotive electronics, and industrial applications.

Konlida’s Core Advantages

Complete Material Development Capability

From conductive fabrics and conductive PI films to foam cores and finished products, Konlida provides integrated manufacturing capabilities.

Professional Foam Core Solutions

• PU foam:
  Custom density options from 18–50 kg/m³
• PORON:
  Stable supply capability for high-precision consumer electronics
• Silicone foam and silicone extrusion:
  Custom hardness, profiles, and temperature resistance up to 280°C
• AIR LOOP hollow structure:
  Ultra-low pressure design for display EMI shielding

Manufacturing Capability

• 45,000㎡ production facility
• 30 conductive foam production lines
• 12 rotary die-cutting machines
• Automated forming equipment
• Clean manufacturing environment
• ISO9001, IATF16949, and ISO13485 certifications

Engineering Support

Konlida provides:

• Material selection support
• Structural optimization
• Prototype development
• Reliability testing
• Mass production support

Our goal is not to let customers repeatedly test different materials by trial and error, but to provide selection recommendations based on real application data.

Final Takeaway

The core material is one of the most important factors determining conductive foam performance.

• Choose PU foam for cost-sensitive, standard applications.
• Choose PORON for precision and consistency requirements.
• Choose silicone foam for high-temperature and high-reliability environments.
• Choose AIR LOOP structures for ultra-low-pressure display shielding.

Selecting the right foam core ensures stable EMI shielding performance, reliable grounding, and longer product lifetime.

Need help selecting the right EMI shielding foam material for your project? Contact Konlida’s engineering team for a customized solution.