[China Glass Network] "The glassware bought at the night market burst when heated in a microwave oven." Mr. Zhu, a citizen of Tianjin, called the hotline, saying that the merchant clearly said that it is thicker than ordinary glass and can be heated. Zhang Jingbo, an associate professor at the Chemistry Department of Tianjin Normal University, said that Mr. Zhu is likely to purchase tempered glass, not a heat-resistant glass containing high-temperature borosilicate.
When the reporter recently visited, it was found that glass products such as bowls, plates, lunch boxes and cups on the market, except for a few brands marked "heat-resistant", most products are not limited by the instructions. Many salesmen have confused the concept of "tempered glass" and "heat-resistant glass", saying that tempered glass of more than ten yuan is thicker than ordinary glass and can be heated. "Glassware is divided into ordinary glass, tempered glass and heat-resistant glass according to different materials. Ordinary glass is fragile, and it may burst when poured into boiling water; tempered glass is easy to burst when the ambient temperature is abrupt; Containing high temperature resistant borosilicate, with excellent heat resistance at 550 °C, can be directly used in microwave ovens and ovens." Zhang Jingbo said that the purchase of heat-resistant glass should pay attention to the coefficient of thermal expansion, the smaller the coefficient of thermal expansion is relatively hot The better the stability and thermal shock resistance in the environment, the standard coefficient of China's heat-resistant glass industry is 4.0 or less.
"At present, there is no clear standard for heat-resistant glassware in China. The so-called 'heat-resistant tempered glass' and 'tempered heat-resistant glass' products appearing on the market do not exist from the material composition. Was misled." The responsible person of the China Daily Glass Association, Tianjin New World Glass Container Co., Ltd. disclosed that the China Daily Glass Association has now formulated the "Management Measures for the Use of Heat-Resistant Glass Products Certification", and the future heat-resistant glass The logo will be affixed for consumer identification.
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