What is Cooling Material?
Cooling materials refers to those fabrics that regulate temperature by absorbing heat, providing a cool and comfortable sensation to the skin. Cool fabric itself cannot cool down; the reason it feels cool to the touch is due to the temperature difference created when the skin’s heat is transferred to the cooler fabric. It’s similar to holding an ice cube, where the immediate contact produces a cooling sensation. Touching the ice silk fabric is like holding an ice cube, providing an instant cool feeling upon contact.
Sometimes people may ask: what fabric keeps you cool? However, the cooling effect is not related to its composition and type of fabric. Whether it is polyester or nylon, both can achieve the cooling effect through post-processing techniques. Any synthetic fabric can be treated with a cooling wash during the final processing stage to achieve a better cooling effect.
How Does Cooling Materials Work?
Common cooling fabrics can be categorized into three types. Firstly, the smoother and more even the fabric, the cooler it feels to the touch because smooth surfaces have a larger contact area, increasing the rate of heat dissipation. Secondly, fabrics made from fibers with high thermal conductivity, such as nylon, polyester, and regenerated cellulose fibers, provide a more noticeable cooling sensation upon contact due to quicker heat transfer. Thirdly, and the best cooling solution, is treating fabrics with cooling agents that enhance thermal conductivity, such as xylitol microcapsules or ice-feeling silicone oil, which significantly improves the cooling sensation by speeding up the heat transfer process. This technology quickly draws sweat away from the skin to the fabric’s surface, where it spreads and evaporates promptly.
In the textile industry, the Q-max value, also known as the coolness coefficient of fabric, is used to indicate the degree of coolness of a fabric. A higher Q-max value signifies a cooler sensation upon immediate contact. In the coolness sensation test for textiles, a heated plate (with a temperature higher than the test sample) is placed on the test sample’s surface (simulating the fabric touching human skin). The peak value of heat transfer is recorded as the Q-max value. The Q-max value measures a fabric’s heat transfer rate, representing the maximum amount of heat that can be transferred through one square meter of fabric in one second. Fabrics with higher Q-max values have better cooling performance as they can transfer more heat away from the body.
One major drawback of cooling materials is that its cooling effect is not permanent. The additive incorporated into the fabric gradually loses its effectiveness with use.
Production and Cost of Cooling Fabrics
The production of cooling materials is achieved by adding a cooling additive during the manufacturing process. The additive can be added during the dyeing bath or during the final setting process. If the fabric needs to be printed, the additive is added after the printing and final setting process.
For example, using Rudolf’s Hydrocool, the additive is used at 2% of the fabric weight. With a standard liquor pickup rate of 60%, it is prepared at 40g/L in the water bath. If a better cooling effect is desired, more additives can be added. However, the amount of additive typically does not exceed 3% of the fabric composition.
In terms of cost, this type of additive is priced at approximately $5 USD per kilogram in China. If their hangtags are needed, an additional fee of approximately ￥0.2 RMB per tag will be charged.
For example, in our recent project, we needed to produce 40,000 swim shorts using 70 GSM pongee fabric. The total fabric weight was 3 tons, requiring 60 kg of cooling additive at a 2% ratio. Since these shorts had printed patterns, adding the additive during the dyeing bath stage could have caused it to evaporate. Therefore, we applied the cooling treatment during the final setting process.
Another cooling technique involves mixing the cooling additive directly into the yarns, allowing the fabric to achieve a cooling effect during the weaving process. However, this method usually requires a large order quantity.
Cooling Materials in Daily Life
Cooling materials is widely used in various fields and industries. Common applications include blankets, sportswear, sun-protective clothing, and workwear, such as cooling vests. Some individuals are highly sensitive to heat, making blankets made with cooling fabric particularly popular among them. Brands like CoolCore, Arctic Cool, and Columbia Sportswear all have specialized products developed based on cooling fabric.
In swim shorts, mainstream fabrics like pongee and 4-way stretch fabric are already made to be comfortable and cool. To achieve an even better cooling effect, we use a cooling additive in the final washing process. This additional step increases the cost by no more than 0.3 USD per piece. And it will significantly enhances the wearing experience for consumers.
For buyers, if you want to get real cooling fabric, please make sure that your suppliers use a cooling additive during the dyeing bath or the final setting process. If they are using branded additives, you can ask for certificates or attach the hangtags provided by the additive company to your garments.