The Amazing Comfort of Mizuno's "BERGTECH EX" Rainwear with a 3-Layer Structure

Have you ever had the uncomfortable experience of rainwear keeping you dry from the outside but getting soaked inside from sweat, causing your shirt and skin to become sticky? The "BERGTECH EX" from Mizuno Corporation uses a 3-layer structure that is strong against both water and sweat. It's water-repellent, waterproof, and breathable, making it ideal for both outdoor and everyday use. We spoke with Shinji Yamamoto, who is in charge of planning rainwear at Mizuno Corporation, about the features of this product.

Japan's Sudden Changes in Weather Demand the Comfort in Rainwear

People often say that mountain weather changes quickly, but recently, even city weather can change abruptly, with heavy winds and rainmaking it hard to rely on just an umbrella. Rainwear that blocks rain but doesn't get soaked inside from sweat is a strong ally. But what are the benefits of a 3-layer structure?
 
"With 3 layers forming one fabric, you might not feel the layers are overlapping when looking at it. In one piece of rainwear, the outer layer, middle layer, and lining each have specific functions. The outer layer is treated with a water-repellent finish. An excellent feature of 'BERGTECH EX' is its high wash durability. Typically, what is called durable water repellency can withstand 20 washes, called '20-wash repellency.' However, 'BERGTECH EX' boasts '100-wash repellency,' the highest rank in water repellency durability."
 
The durability in washing tests and actual wear aren't directly equal. In real use, there's also dirt and friction. That being said, the water repellency of sports equipment generally lasts for about 5 washes, while outdoor gear is around 20 washes. Given this, the fact that 'BERGTECH EX' can withstand about 100 washes is remarkable.
 
"Think of a lotus leaf. Water rolls off the leaf because tiny hairs are standing on it, and the water rolls off the hairs. If these hairs are crushed or dust collects between them, they won't repel water. The water-repellent finish works similarly by having particles stand on the fabric surface to repel water. Invisible water-repellent particles topple under heavy rain, causing water to reach the fabric over time."
 
Yamamoto explains that outdoor equipment's mid-layer, known as the 'membrane,' is what stops water that penetrates the outer layer.