Heat-resistant shock temperature is a basic indicator of heat-resistant glassware, as heat-resistant glass mostly belongs to the borosilicate glass series. Borosilicate glass has a small coefficient of thermal expansion and has good resistance to high temperature and sudden changes in temperature. The disqualification of this project is generally due to issues with the glass material, good thermal stability of heat-resistant glass products, high temperature of sudden changes in heat resistance, and high production difficulty. Its manufacturing cost is 2 to 3 times higher than that of ordinary glass materials. The unqualified project may cause harm to users.
The two important safety indicators for tempered glassware are temperature resistance and fragmentation state. Products with poor heat resistance and rapid change performance can cause tempered glassware to burst due to sudden temperature changes, which can easily cause human injury. These two indicators are not qualified mainly due to incomplete or almost no tempering. In this random inspection, these two unqualified products were basically not tempered, and ordinary glass products were sold as tempered glass products, suspected of deceiving consumers.
The water resistance of the inner surface is a safety indicator, which reflects the physical and chemical properties of glass. Products with poor water resistance on the inner surface are prone to precipitation of alkali metal ions during use, which affects the quality of food. The disqualification of this project is generally due to issues with the glass material, good chemical stability of heat-resistant glass products, and only the use of poor glass raw materials will result in such disqualification.
Different glassware has different characteristics. Tempered glass has good impact resistance, but it is not heat-resistant and generally cannot be used for open flames. In Japan and other countries, it has been clearly stipulated that tempered glass cannot be used in microwave ovens and ovens; Heat-resistant glass has excellent resistance to high temperatures and sudden changes in temperature, making it suitable for use as a food processing container in kitchens, and can be directly placed in microwaves and ovens for use. Consumers can choose glassware according to their own needs. The packaging of tempered glassware is marked with the standard logo, which includes the words "tempered glassware" and "TEMPERED". At present, the concept of "heat-resistant glass tableware and cooking utensils" is still unclear, and Chinese regulations do not require merchants to label their products. Therefore, when purchasing heat-resistant glass utensils, it is necessary to pay attention to the product material, usage environment, and safety precautions clearly stated in the product. The production and manufacturing cost of heat-resistant glass products is relatively high compared to other products. If consumers find that the nominal heat-resistant glass but the price is very low when choosing, they should consider its authenticity.