The Main Materials of Vacuum Bottles
A vacuum bottle is a multi-component system, in which different materials are selected for each part based on its functional requirements.
| Component | Material | Characteristics | Function |
|---|---|---|---|
| Bottle Body | AS (Acrylonitrile-Styrene) | High transparency, good hardness, good chemical resistance | Helps prevent contents from permeating or deteriorating; common choice for serums |
| ABS (Acrylonitrile-Butadiene-Styrene) | Higher toughness, good impact resistance, but lower transparency than AS | Commonly used for packaging requiring corresponding strength | |
| PP (Polypropylene) | Semi-transparent to opaque, excellent chemical resistance and low cost | A cost-effective choice for mid-range products | |
| Glass (with coating) | Excellent texture and barrier properties; inner wall usually coated with SiO₂ (silicon dioxide) and other barrier layers | Further prevents oxygen ingress; high cost, often brand-exclusive | |
| Piston/Inner Container (Sealing Core) | HDPE (High-Density Polyethylene) | Good flexibility, crush-resistant | Fits tightly with the bottle body to form a reliable airtight sealing layer |
| PP (Polypropylene) | Higher rigidity | Used in piston designs requiring stronger supporting structures | |
| Pump System (Control Precision Mechanism) | PP (Polypropylene) | Fatigue-resistant, high chemical stability | Commonly used to make pump housings and springs |
| POM (Polyoxymethylene) | High hardness, low coefficient of friction | Commonly used to make valve stems, ensuring smooth and accurate valve opening/closing | |
| Silicone/EPDM (Ethylene Propylene Diene Monomer Rubber) | Long-lasting elasticity, aging-resistant | Used as sealing rings; key to ensuring long-term leak-proof sealing | |
| Straw | LDPE (Low-Density Polyethylene) | Flexible and easy to bend, ensuring the straw can move freely with the piston. The bottom is usually equipped with a PP or stainless steel gravity ball, which always contacts the liquid by gravity to ensure even the bottom dregs are completely sucked up. | Delivers liquid from the bottle to the pump head |
| Outer Cap | ABS/PP | Mainly decorative and protective; texture can be enhanced via electroplating, spraying and other processes, matching the bottle body design | Provides decoration and protection, and coordinates with the bottle design |
Classification of Vacuum Bottles
Classified by structural principle
| Type | Principle | Advantages | Limitations |
|---|---|---|---|
| Piston-type (Mainstream) | By pressing the pump head, the bottom piston is pushed upward, creating negative pressure inside the bottle to "push" the contents out. | Reliable structure, good sealing performance, residual rate can be as low as 5% | Strict requirements for the processing accuracy of the piston and bottle body |
| Bag-in-Bottle (Premium Preservation) | The contents are squeezed out by compressing a flexible inner bag (usually made of aluminum-plastic composite film), while the rigid outer bottle remains undeformed. | The contents are vacuum-isolated from air, achieving extremely high preservation performance; suitable for easily oxidized active ingredients | Very high cost and low production capacity |
By Bottle Material
All-Plastic Airless Bottles (AS/ABS Body + PP Inner Liner): Commanding over 80% of the market, offering exceptional value for money.
Glass Airless Bottles (Glass Body + Plastic Inner Liner): The standard choice for top-tier brands and luxury products, boasting a premium tactile quality.
Metal Airless Bottles (Stainless Steel Casing): A preferred choice for niche brands, offering superior durability and a distinctive tactile feel.
By Pump Head Type
| Type | Features | Applications |
|---|---|---|
| Round Head Pump | Basic press-type pump with precise dosage control (0.1ml–0.5ml per stroke) | Serums, eye care products |
| Flat Head Pump | Wide-orifice outlet with larger dosage range (0.3ml–1.5ml per stroke) | Face creams, sunscreens |
| Spray Pump | Built-in atomizing nozzle that breaks liquid into fine particles of 50–100 microns | Mists, setting sprays |
| Strawless Pump | Pump head directly contacts the formula; suitable for dispensing high-viscosity products | Foundations, concealers |
Manufacturing and Core Principles
The manufacturing of vacuum bottles is a process of precision engineering; the main steps include:
Detailed Explanation of Technical Principles: Where Did the Air Go?
Vacuum Formation Mechanism:
Initial Press: Depressing the pump head valve stem compresses the internal spring; the piston subsequently moves upward, forcibly expelling the air contained within the bottle through the exhaust valve.
Release: The negative pressure generated by the spring's recoil creates suction at the base of the dip tube, drawing the product into the pump chamber in preparation for the next press.
Subsequent Press: The product within the pump chamber is dispensed, while the piston simultaneously moves upward to fill the void left by the displaced product. Throughout this entire process, external air is prevented from entering the bottle.
The Secret to Zero Residue:
Precision Clearance: The gap between the piston and the inner wall of the bottle is controlled within an extremely narrow tolerance of ≤0.05mm, effectively preventing the product from flowing back beneath the piston.
Gravity Ball Design: The gravity ball located at the base of the straw naturally descends as the product level drops, ensuring that the straw tip remains in constant contact with the product until it is completely used up.