Polyurethane microcellular foam material for railway under-rail backing plate and preparation method thereof

Abstract

The invention discloses a polyurethane microcellular foam material for a railway under-rail backing plate and a preparation method thereof, the polyurethane microcellular foam material is composed of 100 parts by mass of a material A and 93-105 parts by mass of a material B. The material A is composed of 100 parts by mass of polyester polyol, 6-9 parts by mass of a micromolecule chain extender, 0.06-0.10 part by mass of a foaming agent, 0.4-0.6 part by mass of a foam stabilizer and 1.3-1.5 parts by mass of a catalyst; the material B is prepared from the following components in parts by mass: 47 to 50 parts of isocyanate and 50 to 53 parts of polyester polyol; the polyurethane microcellular foaming material disclosed by the invention has the characteristics of light weight, easiness in deformation, good folding resistance, impact resistance, easiness in molding and good buffering performance, can bear higher load, and avoids the problem of stress concentration of the under-rail backing plate; and under the stress deformation condition, the deformation is uniform, and the stress at each part is uniform, so that the service life is longer under the severe track state and huge transportation volume condition of the heavy-load existing line.

Description

technical field [0001] The invention relates to the technical field of heavy-duty railway fasteners, in particular to a polyurethane microcellular foaming material for a railway track lower backing plate and a preparation method thereof. Background technique [0002] The axle loads of trains on existing heavy-haul lines and freight transformation lines in my country are generally 23-25 ​​tons. With the reconstruction of heavy-haul railways, my country's first railway built in accordance with the 30-ton axle load heavy-haul railway standard was completed in November 2014. It was completed in March, and the annual transportation volume is also increasing year by year. Taking the Daqin Railway as an example, the axle load of the train is 25 tons, and the annual transportation volume has reached 445 million tons. [0003] The under-rail pad is set between the steel rail and the concrete sleeper or the integral ballast bed, which plays a role of buffering and damping and reducing ...

AI Technical Summary

Problems solved by technology

[0005] Groove-type rubber backing plate: The groove-type rubber backing plate is a backing plate that has been studied and used in my country for a long time. It is relatively easy to manufacture and generally good in use. A relatively reasonable technical condition for the manufacture and acceptance of rubber backing plates has been formulated, and the product quality is basically obtained. However, its pressure bearing performance, heat aging resistance and oil resistance are not good, and it is prone to crushing during long-term use;

[0006] Thermoplastic Elastomer: Thermoplastic Elastomer TPEE is a block copolymer consisting of a longer soft segment and an appropriate hard segment. It has a two-phase association structure. The crystallization of the hard segment acts as a physical crosslink. Segment amorphous endows the polymer with high resilience, so it has high toughness and high resilience, excellent impact resistance, creep resistance, wear resistance and aging resistance, but its heat resistance is not as good as that of rubber. The decline in physical properties is relatively large, and the compression deformation and durability are worse than those of rubber;

[0007] Polyurethane elastomer: Polyurethane elastomer PU is an emerging organic polymer material with excellent comprehensive properties. The elastic modulus is generally between rubber and plastic. It has good elasticity, elongation and strength while having high hardness. High and excellent wear resistance, large bearing capacity, high impact resistance, fatigue resistance and vibration resistance, etc., but its processing technology is complicated, and it is easy to generate internal heat under heavy load, which affects the performance;

[0008] At present, the under-rail backing plate made of polyurethane elastomer PU material mainly adjusts the static stiffness and improves the heat dissipation problem through the groove design; the stress concentration problem in the local area caused by the groove design is significantly increased, that is, the stress concentration problem is considered Insufficient, affecting the fatigue resistance and service life of the backing plate under the rail

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