Thermos Flask Manufacturer

1. Stainless Steel (18/8 or 304-Grade Stainless Steel)
This type of steel contains 18% chromium and 8% nickel, giving it superior corrosion resistance, durability, and safety for food and beverage storage.
• Corrosion Resistance: Stainless steel is highly resistant to rust and corrosion, even when exposed to moisture for extended periods, ensuring long-term use without degradation.
• Non-Reactive Surface: 18/8 stainless steel is a non-reactive metal, meaning it doesn’t impart flavors or leach harmful chemicals into the liquid, ensuring that beverages maintain their original taste.
• Durability and Impact Resistance: Stainless steel is known for its strength and durability, which makes it ideal for insulated bottles that are often used in outdoor and travel settings. The material can withstand drops, bumps, and everyday wear without denting easily.
2. Lid Materials: Food-Grade Plastics and Silicone
• Food-Safe Plastics (BPA-Free Polypropylene): It’s a highly durable and food-safe plastic that’s commonly used in the construction of bottle lids. It’s free from harmful chemicals like Bisphenol A (BPA), ensuring that no toxic substances leach into your drink. This material is chosen for its lightweight nature, impact resistance, and ease of molding into various lid designs, including flip lids, screw caps, and straw lids.
• Silicone Seals and Gaskets: Silicone is highly flexible, heat-resistant, and non-reactive, which makes it ideal for creating an airtight and watertight closure. These seals help prevent leaks and maintain temperature retention by minimizing heat exchange through the lid.

Absolutely. Every WEVI thermos flask is manufactured using certified food-grade 304 (18/8) or 316 stainless steel that is completely BPA-free and non-toxic. We implement a seamless inner wall construction that prevents bacteria buildup and eliminates any plastic aftertaste. Our products undergo rigorous third-party testing and hold international certifications including FDA, LFGB, and SGS for material safety. The food-safe flask materials ensure pure taste preservation while meeting strict international food contact standards.

Our vacuum insulated flasks deliver exceptional thermal performance. Under standard testing conditions (filling with 95°C hot water or 4°C cold water at ambient temperature of 20°C), our premium stainless steel thermos flask maintains temperatures above 60°C for over 24 hours and keeps beverages chilled below 10°C for up to 12 hours. This industry-leading temperature retention is achieved through advanced double-wall vacuum technology and precision-engineered lid seals that minimize heat transfer. For optimal results, we recommend preheating or pre-chilling your flask before use.

The thermal retention capability of vacuum insulated water bottles stems from their vacuum-sealed layer, which significantly reduces heat transfer. While heat can still move via convection, conduction, and radiation even in a vacuum environment, the process occurs at a dramatically slower rate. This vacuum barrier primarily inhibits conductive heat flow but doesn’t eliminate it entirely. When the liquid inside is hotter than the ambient temperature, the system slows cooling; conversely, when the contents are colder, it delays warming. This dual-action mechanism enables vacuum insulated bottles to effectively maintain both hot and cold temperatures.

Understanding stainless steel differences is crucial for selecting quality insulated bottles. With over 150 stainless steel variants exhibiting distinct properties, NSF international standards mandate that food equipment must use either 200 or 300 series alloys.

① 200 Series
While NSF-certified as food-grade (e.g., 201/202 SS), 200-series steel contains high manganese and minimal nickel, increasing corrosion/rust susceptibility. Typically reserved for industrial applications rather than drinkware, this series offers lower corrosion resistance than premium alternatives. Its role in insulated bottles stems primarily from budget-friendly pricing.

② 300 Series
304 and 316 SS represent austenitic stainless steel - characterized by minimal food-contaminant migration, exceptional media corrosion resistance, and superior hygienic properties. Food-contact products require these alloys. While 304 SS (18/8) dominates daily-use items with proven acid/alkali resistance, 316 SS serves high-end applications like aerospace and food machinery due to enhanced purity and performance, commanding premium pricing.

Ultimately, 304 and 316 SS deliver optimal quality for food-grade water bottles. As professional manufacturers, WEVI's wholesale insulated bottles utilize 304/316/201 stainless steel - ensuring balanced material selection for diverse needs.

A well-known stainless steel water bottle supplier in China, Wevi have rich experience in manufacturing drinkware and containers with custom shapes, caps, logo print, surface finish, packages, etc. We also design for our clients, many designs have registered patents by our clients.

# Size/Capacity: 14oz, 18oz, 24oz, 32oz, 40oz, 64oz,128 oz or other customized capacity.

# Multiple Replacement Caps/Lids: Straw Lid, Sports Lid, Handle Lid, Stainless Steel Cap, Spout Lid, Wooden Lid, Flip Lid, etc.

# Surface Finish: Spraying, Powder Coating, Gradient Ramp, 3D/4D/5D Sculpture, Water Transfer, Air Transfer, Heat Transfer, etc.

# Logo Printing: Silkscreen Print, Laser Engraved, Embossed Logo, Heat Transfer Print, 4D Print, Sublimation Transfer, etc.

# Packaging Box: Egg Crate, White Box, Custom Color Box, Cylinder Box, Display Box, etc.

Enjoy flexible MOQ options tailored to your needs—quantities are fully negotiable to support your market testing phase. We adjust pricing proportionally based on order volume, enabling you to verify our product quality and service standards before confidently scaling orders. Reach out anytime; our team guarantees prompt responses to jumpstart your wholesale partnership.

Of course. We usually provide existing samples free of charge, but a small sample fee is charged for custom designs. The sample fee is refundable when the order reaches a certain quantity.

We usually ship samples via FedEx, UPS, etc. If you have a carrier account, you can use your account to ship; if not, you can pay the shipping fee via PayPal, and we will ship using our account.

It takes about 5-7 days to reach. If you want your own designs, it takes 8-10 days.

Of course, we are professional in OEM/ODM projects and we protect all the designs of every client, we will sign NDA if needed to ensure that we won’t send your artwork to any other clients and won’t sell your OEM items to anyone else. Any questions please send us your inquiry.