I. Material Selection
- Glass Bottles
Glass bottles have excellent chemical stability and do not react with cosmetic ingredients, helping maintain product purity and quality. They feature high transparency and an attractive appearance, but are relatively fragile.
- Plastic Bottles
Common materials include PET, PP, ABS, etc. Plastic bottles are lightweight, shatterproof, and low-cost; however, attention must be paid to potential reactions between certain plastics and cosmetic ingredients.
II. Appearance Quality Requirements
- Foreign Contaminants
No difficult-to-remove contaminants such as rust, oil stains, or water marks are allowed inside the bottle.
- Threads
Thread surfaces must be smooth and even, free of deformation, damage, or roughness.
- Mold Lines
No obvious protrusions, misaligned double mold lines, or sharp burrs are permitted at mold parting lines.
- Stability
The bottom of the bottle must be flat, free of dents, bulges, or deformation.
- Wall Thickness
The bottle wall must be uniformly thick within specified limits, with a minimum thickness of no less than 1.5 mm.
- Discoloration Spots & Bubbles
On the main viewing surface, only 1 or 2 scattered non-concentrated spots or bubbles smaller than 0.5 mm are allowed.
On non-main surfaces, fewer than 3 bubbles smaller than 1 mm are acceptable.
- Pinholes / Porosity
Pinholes smaller than 0.5 mm are permitted on the main viewing surface.
III. Sealing & Capacity Requirements
- Sealing Performance
Good sealing prevents oxidation, deterioration, and contamination of cosmetics, extending their shelf life.
- Capacity
Capacity should be determined based on usage frequency and shelf life to avoid waste and expiration.
IV. Functional Testing
- Dimensional & Position Tolerances
External dimensions and aperture sizes must fall within specified ranges.
- Cap Clearance
Gap tolerance should be between 0.2 cm and 1 cm.
- Air Tightness
Tested via vacuum leak detectors, or by inverting filled bottles for several days to check for leakage.
- Actual Capacity
Actual volume must match the labeled capacity, with deviations within acceptable ranges.
