How a Perceived -10°C Drop Was Achieved! The Structure of the Cocagel Heat-Shielding Hat

With scorching summers becoming the new normal, the role of a hat is changing. It's no longer enough to just block sunlight and shield from UV rays; the key question is how to suppress the rise in head temperature under direct sunlight. This pressing challenge gave birth to the 'Cocagel' hat from Shigematsu Co., Ltd.

Touted with the catchphrase 'a perceived -10°C,' the series has sold a total of 400,000 units since its launch in 2021. It's an item that's found its place in a wide range of settings, from daily outings to outdoor work and adventures. So what ideas and technology brought about this incredible coolness? We spoke with Yoshikatsu Shigematsu, President and CEO of Shigematsu Co., Ltd., to find out.

In an Era When "Just Blocking the Sun" Isn't Enough

Cocagel was developed by Shigematsu Co., Ltd., a comprehensive hat manufacturer founded in 1973. The company, which has long been involved in the planning and manufacturing of hats, ventured into heat-shielding headwear in response to the growing risk of heatstroke amid recent heat waves.

"With heatstroke during intense summers becoming a prominent social issue, we launched a project in 2020 to create a product to combat the extreme heat," Shigematsu explains. "Initially, under the theme of 'supporting hard-working moms,' we targeted mothers who couldn't use a parasol because they were pushing a stroller."

Hats have traditionally been used to protect our heads and bodies from the sun and UV rays. But in today's extreme heat, that's simply not enough. A major challenge has been figuring out how to prevent the head's temperature from rising under direct sunlight. This is where the company focused on the concept of "heat shielding."

The key phrase that showcases this heat-shielding performance is "a perceived -10°C."

"In tests at a public institution, we received a top-tier rating with a 75% heat-shielding rate. But we knew that number alone wouldn't be easy for consumers to grasp, so we developed our own testing device to communicate the benefit more clearly."

In a test using this device, two dummy heads with temperature sensors on top are placed inside a special box. One wears a Cocagel hat, and the other wears a regular hat with no heat-shielding features. Under identical conditions, an incandescent lamp is shone on both. After 15 minutes, the temperatures are compared. The phrase "a perceived -10°C" signifies that a temperature difference of up to about 10°C was observed on the crown of the head.

The Secret to Its Coolness: A Material That Reflects Light and Heat

Let's dive into the technology behind Cocagel. The lineup features a variety of designs, from caps to bucket hats, but here we'll focus on a popular model from the standard series: the 'Cocagel MW Bucket Hat.'

At the heart of its heat-shielding performance is a special material sandwiched between the outer fabric and the inner lining. This sheet-like material creates a thermal barrier that reflects both light and heat.

A typical hat can block sunlight, of course. But under continuous direct sun, the hat itself absorbs heat, which then transfers to your head. The Cocagel's heat-shielding material creates a structure that makes it difficult for this heat to penetrate the inside of the hat.

The brim offers a 100% UV protection rate, while the crown provides 99.9% UV protection. On top of that, its 75% heat-shielding rate not only blocks the sun's rays but also prevents the heat itself from reaching your head. This is the fundamental structure that makes Cocagel so refreshingly cool.

The Reason It's Both Heat-Blocking and Breathable

But for a summer hat, just blocking heat isn't enough. If residual heat and sweat-induced moisture get trapped inside, it can quickly become uncomfortable. That's why a crucial feature for any heat-blocking hat is how it deals with stuffiness.

So, we focused on both the heat-shielding material itself and the hat's construction to boost breathability.

'We use a standard heat-shielding material for the brim, and a material with punched holes for the crown. Plus, we've added slits on the sides to create a structure that lets air flow through easily.'

Beyond its technical features, Cocagel is designed to be a hat you can easily wear every day.

'Since we use a heat-shielding material, we opted for the lightest possible outer fabric and kept other materials to a minimum. For the sweatband, we used a fabric with excellent moisture-wicking and quick-drying properties to boost comfort.'

The 'Cocagel MW Bucket Hat' features an outer fabric made of 80% cotton and 20% rayon. This blend of natural and synthetic fibers creates a texture that's easy for a wide range of users to incorporate into their daily lives.

'Our designs and color palettes are timeless and easy to coordinate with any outfit.'

Machine Washable: A Crucial Summer Feature

For a hat you wear in the sweaty summer, being washable is a must-have feature.

'When selling summer hats, a question we often get from customers is, “Can I wash this?”'

The 'Cocagel MW Bucket Hat' answers that call—it's fully machine washable.

'Cocagel's heat-shielding material doesn't lose its effectiveness with washing, so we've always sold it as a hand-washable hat. However, to make it machine washable, we needed to address potential shrinkage and loss of shape in the outer fabric. For this model, we applied a one-wash treatment to the outer fabric to make it machine-wash-friendly.'

Over 400,000 Units Sold in the Series

Now in its sixth year, the Cocagel series has sold over 400,000 units in total.

'We've heard from our fans, who say things like, "I can really feel how cool it is," "It doesn't get stuffy, even after wearing it for hours," and "I love that it's washable." Looking ahead, we're exploring its use beyond daily wear, considering its integration into uniforms for factory workers and other outdoor professionals.'

From a simple sun hat to a piece of gear that regulates the thermal environment around your head. With its fresh approach of heat-shielding, Cocagel is redefining the role of hats in an age of intense heat.