Appearance and Initial Sensory Judgment
- Surface Quality: High-quality rubber gaskets should have a smooth, flat surface, free of bubbles, cracks, impurities, and obvious unevenness. The presence of bubbles or pinholes may indicate insufficient vulcanization or uneven mixing of raw materials.
- Color and Gloss: High-quality products have a uniform, full color and a natural luster; inferior products often have a dull, grayish color or mixed colors, possibly due to the addition of recycled rubber or excessive impurities.
- Odor: High-quality rubber gaskets have only a slight rubber smell that dissipates quickly; a pungent, unpleasant odor that lingers for a long time may indicate the use of inferior raw materials or excessive additives.
Core Physical and Mechanical Performance Indicators
These indicators are key to measuring quality and can be verified through test reports:
- Shore A Hardness: Reflects the degree of vulcanization and strength in use. The common range is 60±5 Shore A. Too high a Shore A indicates brittleness, while too low a Shore A indicates poor resilience.
- Tensile strength and elongation: These reflect the material's toughness and should conform to GB/T 528-2009 standard. Higher values indicate stronger tensile strength.
- Compression set: This measures the durability of the seal. It should be ≤15%. Lower values indicate better elastic recovery and a longer seal life.
- Adhesion strength: For linings or composite structures, it must be ≥1.0 MPa; for neoprene rubber, it can reach over 1.5 MPa to prevent delamination failure.