The rubber layer thickness is typically restricted to no more than 10 mm, primarily due to three interrelated factors: heat vulcanization process heat transfer efficiency, risk of reduced interlayer bonding strength, and marginal returns on cushioning performance. This limit is not an absolute physical constraint but rather a practical threshold beyond which internal vulcanization becomes uneven, delamination between layers may occur, or performance gains become negligible.
Key Limiting Factors:
**Heat Transfer Bottleneck in Vulcanization**: The three-in-one panel requires one-time high-temperature (140°C–160°C) vulcanization. Rubber has poor thermal conductivity; when the thickness exceeds 10 mm, the interior cannot reach sufficient cross-linking temperature, leading to issues such as "over-baked exterior and under-cured interior" or foaming defects, which degrade mechanical properties.
**Decline in Interlayer Bond Strength**: Excessively thick rubber layers generate significant shear stress during thermal expansion/contraction or impact loading, increasing the risk of debonding at the ceramic-rubber interface. Engineering validation shows that 5–8 mm provides optimal impact absorption; further increases do not enhance bonding strength and instead raise failure risks.
**Marginal Performance and Structural Balance**: The primary function of rubber is energy absorption, not load-bearing. A thickness of 5–10 mm effectively dissipates most impact energy from falling materials. Exceeding this range reduces overall structural rigidity, potentially causing installation surface irregularities or loose bolt fastening, while also significantly increasing cost and weight.