How much do you know about waterproof breathable membrane? How to identify true and false waterproof breathable membrane

In the field of construction, waterproof and breathable membranes are mainly used in steel structures and wooden structures. The domestic market is more confusing. Most of the brands promoted through the Internet do not have the ability to produce waterproof vapor-permeable membranes, but use simple non-woven fabrics and glue compound fake Fake products. The following editor will introduce you to the relevant knowledge about waterproof and breathable membranes.

Working principle of waterproof breathable membrane

In the state of water vapor, the water particles are very fine. According to the principle of capillary motion, the water can penetrate into the capillary to the other side smoothly, so that the phenomenon of steam permeation occurs. When the water vapor condenses into water droplets, the particles become larger. Due to the surface tension of the water droplets (the water molecules "pull against each other"), the water molecules cannot smoothly leave the water droplets and penetrate to the other side, which is to prevent Water penetration occurs, making the vapor-permeable membrane waterproof.

Waterproof breathable membrane material

The technology of waterproof breathable membrane was first introduced from European and American countries. However, the production process of domestic products is varied, and the quality of products of various manufacturers is uneven, and a unified quality standard has not been formed. In fact, the waterproof breathable membrane mainly consists of three layers: PP spunbond nonwoven fabric, PE polymer breathable membrane, and PP spunbond nonwoven fabric. The role of spunbond non-woven fabric is mainly to enhance tensile force and hydrostatic pressure and protect the intermediate layer (breathable film). The real ventilation is mainly relying on the middle layer PE polymer breathable film.

Waterproof breathable membrane price introduction

The price of waterproof and breathable membrane mainly consists of raw materials, production process and equipment investment cost. At present, some domestic manufacturers spread that waterproof and breathable membranes are auxiliary materials, and the cost is very low and the price is not lower than the main materials such as thermal insulation cotton. This is nonsense. Such remarks are purely harming and misleading consumers. Because these manufacturers simply do not master the production process of waterproof and breathable membranes, they use very simple laminating nonwoven fabric or hot melt adhesive spraying composite nonwoven fabric equipment to produce fake and inferior waterproof and breathable membranes, misleading consumers with fallacies. To achieve the ulterior motive.

How to identify true and false waterproof breathable membrane

1. Laboratory testing

Test items: a. Temperature resistance b. Water vapor throughput (ie air permeability) c. Hydrostatic pressure d. Anti-aging ability

The real waterproof breathable membrane is not compounded with glue, so the temperature resistance is -40,100 degrees (EU CE standard, American ASTM standard). It is not produced with polyethylene or TPO film, so the air permeability should exceed 1500g / square / 24 hours. The production of polyethylene or TPO film is basically not breathable. In hydrostatic pressure test, the hydrostatic pressure of the thin waterproof breathable membrane is at least 1.5 meters, and the thick waterproof breathable membrane is at least 2 meters. Anti-aging is necessary, because PP materials are easily aging under ultraviolet light, and some fake waterproof breathable membranes are produced with poor recycled materials. This waterproof breathable membrane is easily aging and degrading during the construction process.

2. Simple hands-on detection

On the surface, there are obvious pressure points on both sides of the waterproof and breathable membrane. That is because the production process is compounded by hot pressing. Please note that it is not the dots of the non-woven fabric itself, but the obvious overlapping dots. To tear off the waterproof and breathable membrane, first of all, the middle polymer layer should be a milky white very soft waterproof and breathable layer, because it is compounded by hot pressing, there should be pressure points on this layer of film. In addition, gently press the non-woven fabric and the film with your hand. If you feel sticky to your hand, you can conclude that it is hot-melt adhesive, then this is a fake waterproof breathable film. Because the hot-melt adhesive is stuck even at room temperature, these three layers of material will soon blister and delaminate, automatically peeling off.

The above is the introduction brought to you by the editor. If you want to know more related knowledge, please continue to pay attention to Qijia consultation, please stay tuned for more exciting consultations.

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