Polymeric Plugging Composition for Railroad Tie Spike Hole Repair

The patent modifies the chemical composition parameters of the polymeric material, specifically incorporating a blend of polyols with different molecular weights and structures (e.g., polyether polyol, polyester polyol, and glycerol) along with controlled amounts of catalyst and filler. This parameter optimization allows the material to achieve high spike withdrawal force (≥1,200 lbs) while maintaining manageable viscosity for easy application at various temperatures.

The patent carefully balances the catalyst concentration (0.5-5% by weight based on total composition) and polyol ratio to control the curing reaction rate. This parameter optimization enables the material to achieve adequate hardness within 30-60 minutes while simultaneously achieving high spike withdrawal force (≥1,200 lbs), resolving the contradiction between fast setting and strong bond strength.

The patent creates a composite polymeric formulation combining multiple polyol types (polyether, polyester, glycerol) with complementary properties. The polyether component provides low-temperature fluidity while the polyester and glycerol contribute to high-temperature strength and low-temperature viscosity reduction. This composite approach enables the material to maintain low viscosity at freezing temperatures for easy application while achieving ≥1,200 lbs spike withdrawal force when cured.

The patent optimizes the hydrophobicity parameter of the polymeric formulation by selecting polyols with appropriate chemical structures and adding moisture-curing agents in controlled amounts (1-10% by weight). This parameter adjustment enables the material to tolerate high moisture environments (achieving ≥1,200 lbs spike withdrawal force even in wet conditions) while keeping the formulation relatively simple and cost-effective to manufacture.