The core technology of waterproof membranes lies in achieving a balance between "waterproofing" and "breathability" through physical barriers or special structures. They are mainly divided into three categories: microporous, non-porous, and composite.
Technical Principles and Classification
Microporous Waterproof and Breathable Membranes
Principle: The membrane surface is covered with micron-sized pores, allowing only water vapor molecules to pass through while blocking liquid water droplets.
Representative Materials: Polytetrafluoroethylene (PTFE), Polyurethane (PU) microporous membranes.
Characteristics: Good breathability, but micropores are easily clogged, affecting performance.
Non-porous Waterproof and Breathable Membranes
Principle: Relying on the hydrophilic and hydrophobic properties of polymer chains, water vapor is transferred through "adsorption-diffusion-desorption," completely blocking liquid water without pores.
Representative Materials: Thermoplastic Polyurethane (TPU), Thermoplastic Elastomer (TPE).
Characteristics: Good stain resistance, but breathability is greatly affected by membrane thickness and temperature.
Composite Waterproof and Breathable Membrane
Principle: Combining different materials to leverage their respective advantages, such as microporous membranes enhancing breathability and non-porous membranes improving durability.
Representative Materials: Polyurethane/polyethylene composite layer, polypropylene composite membrane.
Features: Excellent overall performance, making it a mainstream technology in the field of building waterproofing.