The role, characteristics and types of foam materials?

 

The foam material is a high molecular polymer with many small cells, the solid phase is a polymer matrix, and the small cells are filled with other gases. Widely used in mobile phones, LCD backlights, display screens, notebook computers, automobiles and other fields. So, what are the functions and characteristics of foam materials? What are the categories?

The role of foam material

1. Panel interlayer: no pollution, prevent loosening, prevent impact noise, and prevent sticking.

2. Around the LED: prevent light leakage, absorb shock, and have high air tightness.

3. The lower periphery of the PCB: absorb shock, absorb vibration, fill gaps, and heat insulation.

4. Keyboard gasket: rebound, no pollution, good dimensional stability.

5. Around the battery: no pollution, absorb impact sound, improve air tightness.

6. Foot pads: good friction, no pollution, good dimensional stability.

7. The rear pad of the disk drive: absorbs vibration, prevents impact noise, and improves air tightness.

8. Friction pad: good friction, no pollution and good dimensional stability.

9. Disc cover cushion: absorb vibration, block motor noise, shockproof and improve air tightness.

10. Around the speaker: prevent noise and fill the gap.

11. Around the LCD: dustproof, absorbing shock, filling gaps, improving shading

 

Features of foam material

1. Very good shielding effect at low pressure, the shielding efficiency exceeds 90dB.

2. Elastic and light weight.

3. Anti-corrosion nickel coating can prevent electrochemical corrosion.

4. Low surface contact resistance.

5. Fast pressure-sensitive fixation.

6. Customers can specify the length.

7. Numerous cross-section options.

8. UL class fireproof.

9. The quality of the products that can be pasted with Mylar (valet double-sided tape) is stable.

10. It is resistant to heat and pressure, not easy to fall off, and has high tensile strength.

11. After the product is installed, the original quality is maintained for 72 hours after the low temperature -20 ℃ to the high temperature 80 ℃.

12. It has the characteristics of convenient use, free bending, ultra-thin volume and reliable performance.

Foam is divided into the following types according to the different materials:

1. PU foam (polyurethane foam) is made of polyurethane foam.

2. Aluminum foil foam

Aluminum foil foam is made of soft pure aluminum foil and glass fiber composite aluminum foil cloth instead of conductive cloth to wrap flame retardant foam. Surface impedance ≤ 0.016Ω, with excellent shielding performance of metal, its temperature resistance can reach 130 ℃, low cost, can meet the needs of product cost pressure. The conductive foam of aluminum foil cloth has excellent performance, and its shielding performance exceeds 100db. It has high elasticity, reduces the conductive resistance of the contact surface, resists corrosion, and improves the compatibility of the metal plating of the connector assembly.

3. Conductive foam

The conductive foam wraps the conductive cloth on the flame-retardant sponge. After a series of treatments, it has good surface conductivity and can be easily fixed on the device to be shielded with adhesive tape. Shielding materials with different cross-sectional shapes, installation methods, UL ratings and shielding effectiveness are available.

Conductive foam can be divided into: aluminum foil cloth foam, conductive fiber cloth foam, gold-plated cloth foam, carbon-plated cloth foam, etc.

4. Microporous polyurethane foam

Microcellular polyurethane foam has excellent compressibility and high resilience, high-tech foam with moisture and chemical resistance. This foam is divided into K series and E series. And can fully meet a variety of environmental requirements for sealing and energy absorption. The pressure-sensitive adhesive can be applied on one side according to the demand, which avoids the back-adhesive operation and has a high cost performance. The PET-FLLM or paper is used as the supporting surface to ensure the flatness of the foam, which is suitable for various die-cutting processes.