How does glue polyurethane (PU) board maintain its resilience and prevent permanent deformation under long-term high-load compression?
Publish Time: 2026-02-18
Glue polyurethane (PU) board is widely used in industrial applications such as mechanical limiting, equipment vibration damping, and collision buffering due to its excellent compression resistance, abrasion resistance, high elasticity, and energy absorption capacity. However, under long-term high-load compression, many elastic materials will undergo permanent deformation and functional failure due to molecular chain slippage, cross-linking structure destruction, or plastic flow. The reason glue polyurethane (PU) board can maintain good resilience under harsh conditions is due to its unique molecular structure design, cross-linking network control, and precise synergy between formulation and process.1. High Cross-linking Density Network: The Molecular Basis for Resisting Plastic FlowPolyurethane is a block copolymer formed by the stepwise polymerization reaction of isocyanate and polyol. Its microstructure contains hard and soft segments. Hard segments aggregate through hydrogen bonding and microphase separation to form physical cross-linking points, while some formulations also introduce chemical cross-linking agents to construct a covalent cross-linking network. This "physical + chemical" dual cross-linking structure significantly improves the material's elastic recovery ability. Under high-load compression, even if the soft segments deform, the hard segment micro-regions can still act as stabilizing anchors, preventing irreversible slippage of molecular chains and effectively suppressing permanent deformation.2. Optimized Hardness and Formulation Balancing Resilience and Load BearingThe hardness of polyurethane gaskets is typically adjustable between Shore A 70 and 95. Higher hardness results in stronger load bearing capacity, but may decrease resilience; conversely, excessive softness leads to easy crushing. To balance these two aspects, engineers achieve optimal performance ratios by adjusting the isocyanate index, the ratio of soft to hard segments, and the type of filler. For example, using high-functionality polyols can increase crosslinking density; adding reinforcing fillers such as nano-silica can enhance compressive strength without significantly sacrificing elasticity. High-quality polyurethane gaskets, after a 30% compression rate and a 70℃×22-hour test, can maintain a compression set of less than 10%, ensuring that they can still recover their original thickness and function after long-term use.3. Thermal Stability and Anti-Aging Design Extend Service LifeHigh temperatures accelerate the thermal oxidative degradation of polyurethane molecular chains, weakening the crosslinked structure and exacerbating permanent deformation. Therefore, antioxidants and heat stabilizers are commonly added to high-performance gasket formulations to effectively delay material aging. Simultaneously, replacing traditional polyester gaskets with polyether or polycarbonate polyols, which offer superior heat resistance, further enhances dimensional stability at 80–100°C. These measures allow polyurethane gaskets to remain undeformed for years, even in high-temperature areas such as engine compartments and near industrial ovens.4. Structural Design Aids Uniform Stress DistributionBesides the material itself, the gasket's geometry also affects compression behavior. For example, using rounded edges, tapered cross-sections, or internal openings can guide uniform stress distribution, preventing microcracks or collapse caused by localized stress concentration. In restraint and cushioning applications, stepped or multi-cavity designs can achieve "staged compression"—soft energy absorption in the initial stage, followed by increased stiffness to prevent over-compression, thus protecting the material from overload and extending rebound life.In summary, glue polyurethane (PU) board, with its controllable cross-linking network, scientifically designed formulation, thermal stabilization treatment, and optimized structure, exhibits superior resistance to permanent deformation under long-term high-load compression. It is not merely a simple cushioning component, but a precision functional element integrating polymer chemistry, materials engineering, and mechanical design. For these reasons, polyurethane gaskets have become the preferred choice for reliable, durable, and high-performance vibration damping and limiting solutions in modern industry.
