Rail tie plate and preparation method thereof

Abstract

The invention provides a polyurethane rail tie plate which is a microporous polyurethane elastomer made from raw materials of a polyalcohol composition, an NCO-blocking modified isocyanate curing agent and a foaming agent. The invention further provides a preparation method of the polyurethane tie plate, comprising the following steps: adding the foaming agent to the polyalcohol composition; adding the modified isocyanate curing agent to a mixture of the polyalcohol composition and the foaming agent according to a certain proportion at the temperature of 25-60 DEG C; and stirring and evenly mixing the obtained mixture, casting for molding, curing, taking out and then post-curing to obtain the polyurethane tie plate. The dynamic-static stiffness ratio of the tie plate is not more than 1.5;fatigue tests for 3 million times show no damage to appearance of the tie plate and low dimensional change rate of not more than 30%, thus achieving good damping and cushioning effects and enhancing comfortableness when a train runs; and meanwhile the rail tie plate has good durability.

Description

technical field [0001] The invention relates to a rail backing plate, in particular to a microporous polyurethane elastomer rail backing plate and a preparation method thereof. Background technique [0002] With the continuous improvement of people's requirements for train speed, how to solve the vibration and impact caused by the high-speed running of the vehicle has become a very critical issue. In order to reduce vibration and reduce noise, rail pads are designed. In practical engineering applications, this kind of rail backing plate is located between the cement sleeper and the steel rail, and uses its own elasticity to reduce the vibration and noise generated between rigid materials. Therefore, it is required that the spring constant of the railway backing plate has a very obvious impact on the shock absorption and noise reduction effects, and the spring constant is a parameter that characterizes the static stiffness of the product. If the spring constant is too high,...

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Problems solved by technology

[0006] Usually, a two-component foaming system is often used in the preparation of polyurethane foaming systems, that is, the preparation raw materials are divided into A and B components, of which A component is polyol, catalyst, foaming agent, additives, etc., and B component is composed of polyisocyanate Composition, in fact, the moisture content has the most serious impact on the performance of the final product. When the foaming agent is water, the A component already contains water, so during the storage of the A component, its moisture content is easily affected by the external environment. The influence of moisture content, especially when it is in the humid south or the lid of the barrel storing component A has been opened, this effect is particularly obvious, which in turn affects the quality stability of the final product

[0007] CN101125909A discloses a foaming solid polyurethane elastomer based on high-melting point polyisocyanate and its production method, which is used for vibration isolation components, but the isocyanate used is NDI, PPDI, TODI, and the melting point of the raw material is high, which is inconvenient to use and high in raw material cost

[0008] In practical application, as a kind of backing plate under the track, the spring constant of the rail backing plate only reflects its static performance, and the more important index reflecting the comfort should be related to the dynamic performance, but there is no such kind in the above patent documents. data reporting

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