Office Chair Parts & Structure Explained

Office chair parts and structure are complex, involving multiple components with distinct functions and material requirements.

I. Main Structural Components

1. Five-Star Base: It needs to bear both static and dynamic loads of the chair. The industry requires it to pass a 150kg static load test. The material must have high impact resistance, rigidity, and fatigue resistance.
2. Backrest Frame: It requires good toughness to prevent brittle fracture while maintaining dimensional stability to avoid softening in summer or becoming brittle in winter.
3. Seat Pan Chassis: It needs to have creep resistance to prevent seat collapse due to material deformation after half a year of use.
4. Armrests: They need to support repeated adjustments. The surface must be resistant to sweat corrosion and scratches, and the material should balance strength and surface durability.
5. Backrest Connectors, Gas Lift Sleeves, and Lumbar Support Brackets: These components need to meet specific mechanical properties. For example, the gas lift sleeves need to be compatible with the stability requirements of the lifting mechanism.

II. Material Selection and Modification

Virgin materials cannot meet performance requirements: Pure PP (polypropylene) has high brittleness, pure PA (nylon) is expensive, and pure PC (polycarbonate) has poor drop resistance and average dimensional stability. The industry solves this problem through material modification:

1. Add glass fibers to enhance material strength and rigidity;
2. Add toughening agents to improve impact resistance;
3. Add weathering agents to improve environmental adaptability;
4. Add sweat-resistant agents to prevent corrosion on the surface of armrests. Over 70% of structural components use modified materials rather than virgin materials.

III. Supplier Classification

1. International Chemical Giants: Such as BASF, Covestro, and SABIC, they provide globally standardized products with complete certifications but have high costs and slow customization responses.
2. Local Modification Factories: They customize formulas according to the specific working conditions of chair factories, offering high flexibility but requiring strict quality control.

IV. Quality and Safety Issues

1. International Recall Cases: In 2023, office chairs made in China were recalled in the United States and Canada due to the risk of backrest breakage, resulting in 12 reports (including 10 injuries). In 2025, the WorkPro Momentum series was recalled in the United States due to the risk of bolt failure, resulting in 7 reports (including 2 minor injuries).
2. Domestic Sampling Inspection Problems: In 2024, the State Administration for Market Regulation found 15 batches of non-compliant products during sampling inspections. Stability issues were particularly prominent, and it is necessary to focus on structural strength and material durability.