The stainless steel vacuum insulated cup (also known as the "Meiyuan Cup") is a daily-use item manufactured primarily from stainless steel. It employs a double-walled, vacuum-sealed structure to block thermal conduction, thereby enabling both heat retention and cold insulation functions. The product line encompasses over 20 distinct models, including screw-top, wide-mouth, and child-specific designs. The inner liner and all components that come into contact with liquids must be constructed from 06Cr19Ni10 austenitic stainless steel or materials of equivalent corrosion resistance; the outer casing must comply with the GB/T 20878 standard. The cup rim utilizes welding or thermal fusion processes to create the vacuum layer. Applicable standards include GB/T 29606-2013 (*Stainless Steel Vacuum Cups*) and GB/T 40355-2021 (*Stainless Steel Vacuum Insulated Containers*), the latter of which came into effect on March 1, 2022. A group standard issued by Zhejiang Province in 2016 mandates that products undergo 26 specific inspections-including chemical analysis, thermal insulation performance testing (maintaining temperature difference over a 6-hour period), and salt spray testing-while also introducing new functional requirements such as splash prevention and electrical safety (IPX6 water resistance). In 2024, supervisory spot checks conducted in Suzhou on 25 product batches revealed that one batch failed to meet standards regarding thermal insulation performance and impact resistance. Conversely, quality comparison testing conducted in Hangzhou in 2025 demonstrated that products manufactured in Hangzhou performed exceptionally well in terms of migration limits, the application of 316L stainless steel, capacity accuracy, and thermal insulation efficiency.
When purchasing, consumers should verify the presence of 304 or 316 stainless steel markings, food-grade silicone sealing rings, and the citation of applicable standards. Leak-tightness can be tested by inverting the cup; additionally, one should inspect the permanent markings on the cup body to identify the manufacturer's name, product specifications, stainless steel grade, and applicable standards. Prior to use, the cup should be cleaned and sanitized using boiling water or a neutral detergent; preheating the cup can enhance its thermal insulation performance. Usage contraindications include avoiding the storage of carbonated beverages, acidic liquids, milk, traditional Chinese medicine, or hot beverages exceeding 50°C (particularly in children's straw cups), in order to prevent high temperatures and internal pressure from causing corrosion of the inner liner or structural failure.
Regulatory authorities, through random inspections, have identified issues in certain products-such as excessive manganese levels and missing labeling. It is recommended to prioritize the selection of compliant products that bear the GB 4806.9-2016 and GB/T 29606-2013 standard markings.