Near the end of the year, a new wave of cold waves struck, and temperatures in many places even exceeded historical extremes. People began to pay attention to thermal products, especially self-heating underwear, which has been in a state of continuous popularity since this year.

Judging from the receipts of major e-commerce, the price of self-heating underwear ranges from tens of yuan to hundreds of yuan, and the sales volume exceeds 10,000 yuan. The highest temperature rise can reach 8℃? The average fever rate in 30 minutes is 3. 1℃? Product performance promotion is even more eye-catching.

I bought two sets of hot-selling self-heating underwear from the Internet at a price of about 100 yuan. Then I took them to the National Textile Product Quality Inspection Center, and the staff tested them according to the relevant national standards.

Before the test, the staff dried and dehumidified the samples for more than four hours in advance to ensure that the water was completely removed, and then put them into the dryer.

According to relevant national standards, the test was carried out at 20℃ and 90% humidity.

The test results show that the highest temperature appreciation of the two kinds of self-heating underwear reaches 9.5℃ and 7.6℃ respectively, far exceeding the standard requirement of 4℃.

The average temperature rise within 30 minutes is required to be greater than or equal to 3℃. One of the two products is 3.8℃, which is just up to standard, and the other is 2.8℃, which is not up to standard.

The experimental results show that self-heating underwear can indeed heat up, but experts say that laboratory data and practical application can not be completely equated.

It can also be seen from the experimental data chart that the temperature of the two kinds of self-heating underwear reached its peak about 5 minutes after the test began, and then the temperature began to drop. Within 30 minutes, the temperature of both products changed from low to high, and then from low to high.

Experts pointed out that this is because the humidity of the test environment has been kept at 90%. When the fiber of self-heating underwear is saturated with water, it will stop absorbing water and heat, and instead absorb human heat and release moisture. In other words, the temperature of self-heating underwear rises quickly and falls quickly.