Polyurethane Grouting Material for Coal-Rock Reinforcement
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Solution Overview
Problem
Existing polyurethane grouting materials for coal-rock mass reinforcement in coal mines face challenges in meeting the new safety standards due to high reaction temperatures and insufficient compressive strength, posing safety hazards and non-compliance with industry standards.
Innovation Solution
A grouting material is developed by designing a prepolymer component to release reaction heat in advance, using specific polyether polyols, catalysts, and flame retardants, which reduces the maximum reaction temperature below 100°C and maintains sufficient mechanical strength, meeting the requirements of coal-rock mass reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane grouting material is used for reinforcement, then adhesion and flexibility are improved, but reaction temperature increases causing safety hazards
Solution Approach 1:
The patent introduces a prepolymer component that undergoes preliminary reaction before the final grouting process. This preliminary action releases part of the reaction heat in advance, controlling the maximum reaction temperature to not greater than 100°C during the actual grouting operation, thereby resolving the contradiction between maintaining good adhesion and controlling reaction temperature.
2Reliability
If polyurethane grouting material is used for reinforcement, then flexibility and deformation resistance are improved, but inflammability increases causing safety hazards
Solution Approach 1:
The patent converts the harmful inflammability of polyurethane grouting material into a beneficial property by adding flame retardant components. The flame retardants inhibit combustion and improve fire resistance while maintaining the flexibility and deformation resistance of the polyurethane material, thus resolving the contradiction between flexibility and inflammability.
3Object-generated harmful factors
If flame retardants are added to reduce inflammability, then fire resistance is improved, but compressive strength may be affected
Solution Approach 1:
The patent optimizes the parameters of the flame retardant components and their proportions in the formulation. By carefully selecting flame retardant types and adjusting their content within specific ranges, the patent achieves both fire resistance requirements and maintains compressive strength of not less than 40 MPa after curing, resolving the contradiction between fire resistance and compressive strength.
4Temperature
If reaction heat is released in advance through prepolymer, then maximum reaction temperature is reduced, but preparation complexity increases
Solution Approach 1:
The patent segments the grouting material into multiple components including a prepolymer component and other grouting components. The prepolymer component undergoes preliminary reaction to release part of the reaction heat in advance, controlling the maximum reaction temperature to not greater than 100°C. This segmentation approach, while adding preparation steps, ensures safe underground construction by controlling reaction temperature.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures safe construction by lowering reaction temperatures, achieving compressive strengths of not less than 40 MPa, and meeting safety standards for coal-rock mass reinforcement, reducing the risk of accidents and ensuring compliance with industry standards.
Implementation Method 1
the polyurethane grouting material has reaction exotherm, high reaction temperature of the system
Implementation Method 2
0.05 parts to 0.1 parts of a catalyst; 0.05 parts of the catalyst
Implementation Method 3
21 parts to 26 parts of a flame retardant; the latest safety production industry standard requires that polymer materials for strengthening coal-rock mass in the coal mines have a maximum reaction temperature of not greater than 100° C.
Data Source
AI summary
The present disclosure relates to a grouting material for reinforcement of coal-rock mass in low-temperature mining. The material includes a component A and a component B, where the component A includes 100 parts of a polyether polyol A and 0.05 parts to 0.1 parts of a catalyst; the component B includes 18 parts to 24 parts of a polyether polyol B, 21 parts to 26 parts of a flame retardant, 50 parts to 61 parts of polyisocyanate, and 0.05 parts of the catalyst. A preparation method of the grouting material includes the following steps: stirring the polyether polyol A and the catalyst to obtain the component A; drying the polyether polyol B and mixing with the polyisocyanate and the catalyst, and conducting a reaction to obtain an isocyanate prepolymer; adding the flame retardant to the isocyanate prepolymer, and adjusting a viscosity to obtain the component B.