①、Introduction - A foam liner with multiple functions
Why is the small foam material only 0.5mm~3mm, which can be used for leak prevention of cosmetic bottle caps and can also be laid under the floor for sound insulation and shock absorption? The reason behind it turned out to be its unique closed cell structure.
②、Core decryption: What is a closed cell structure?
1.For example, it's easy to understand at a glance
◆ The closed cell structure is like countless tiny, independent, sealed small air pockets, each bubble tightly closed and not connected to each other.
◆ The perforated structure is like a sponge, with interconnected pores that allow air and water to freely enter and exit.
2.How did 'closed pores' come about?
Simply put, it is formed through chemical or supercritical foaming processes. Let each bubble form a tiny, independent 'little house'.
③、Waterproof and moisture-proof - why can water molecules be isolated
1. Principle: Two "lines of defense"
◆ The first line of defense (material itself): PE (polyethylene) is inherently hydrophobic and does not like water.
◆ The second line of defense (closed cell structure): In order for water molecules to penetrate, they must pass through layers of dense polymer cell walls. But since each bubble is independently sealed, water molecules have no channel to enter the interior of the material and are firmly blocked on the surface.
2.How strong is the effect?
◆ Extremely low water absorption rate: The water absorption rate of PE foam material can be as low as 0.01 g/cm ², almost zero, even with a thickness of only 1mm, it can meet the needs of waterproof and moisture-proof.
◆ Application scenarios: Therefore, it can be used in humid environments, such as bottle cap sealing liner, disposable water bottles, luggage liners, bathroom floor mats to prevent mold, and pipeline insulation to prevent condensation.
④、Sound insulation and noise reduction - why do sound waves get lost?
1. Principle: It's not about "absorbing" sound, but about "consuming" sound
◆ Porous materials (such as sponges) allow sound waves to enter the hole and absorb sound by dissipating energy through friction.
◆ The sound insulation principle of PE closed cell liner is different. When sound waves (noise) collide with the surface of the liner, energy is transferred to these countless independent bubbles.
2.How is energy consumed?
◆ Reflection and attenuation: During the propagation of sound waves, when encountering layers of bubble walls, some are reflected back, while others cause vibration of the bubble walls when penetrating, converting sound energy into mechanical energy (deformation) and consuming it.
◆ Isolation "sound bridge": The closed cell structure can also effectively block the path of sound propagation through solid structures, playing a role in sound insulation.
3. Actual effect
For example, a 5mm thick PE foam material can achieve significant air sound insulation effect. Therefore, it is often used as a shock absorber pad for floating floor slabs to solve the problem of collision sounds (footsteps, dragging sounds) from upstairs and downstairs.
⑤、Summary - The "Chain Reaction" Caused by Closed Cell Structure
In addition to waterproofing and sound insulation, this independent closed cell structure also brings a series of other advantages:
◆ Thermal insulation: The internal air is enclosed, and the thermal conductivity is low (≤ 0.038 W/(m·K)). At a certain temperature (<80℃), the PE foam liner can effectively isolate heat transfer.
◆Buffer and shock absorption: Each bubble is an independent "buffer airbag" that rebounds after bearing impact, absorbs impact force, and counteracts vibration.
Are you looking for waterproof and soundproof materials or liner with specific thickness or hardness? Welcome to contact us for samples and exclusive solutions. BAIJUR has been specializing in the production of PE foam materials for over ten years, using only environmentally friendly physical foaming methods without additives. The materials are waterproof and moisture-proof, and comply with the EU RoHS directive and FDA standards.
