The physical properties of glass products are poor, and they are more fragile than porcelain products when they encounter shocks, bumps and sudden changes in heat and cold. Therefore, even if there are glass tableware, most of them are tempered glass, and the cost is higher. Therefore, among non-porcelain tableware, plastic tableware has a price advantage and metal tableware has a physical advantage.
Glass processing belongs to thermoforming processing, and the processing technology is complex, which requires high machine cost, while porcelain can be produced in large or small workshops, which greatly reduces the entry of porcelain tableware and makes it more popular.
The first choice for drinking water should be a glass. Don't think that glass is just transparent and beautiful. Among all the cups made of materials, the glass is the healthiest. This kind of glass contains no organic chemicals in the firing process. When people drink water or other drinks from glasses, they don't have to worry about chemicals being drunk into their stomachs. Moreover, the glass surface is smooth and easy to clean, and bacteria and dirt are not easy to breed on the glass wall. Therefore, it is the healthiest and safest for people to drink the water in the glass.
Extended data
Coiling method
1, whiteness: the exposed glass should have no obvious color.
2. Bubbles: bubbles with a certain number, width and length are allowed, but bubbles that can be punctured by steel needles are not allowed.
3. Transparent pimple: refers to the vitreous body with uneven melting. Glass with capacity less than 142mL, and no more than one glass with length less than 1.0mm; Glass with a capacity of 142~284mL, and no more than one glass with a length of 1.5mm, and no transparent protrusions are allowed on the glass body of 1/3.
4. Impurity: refers to opaque granular sundries, the length of which shall not exceed 0.5mm and 1.
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