A polyurethane microcellular foamed ballast mat and a method of making the same

Abstract

The application belongs to the technical field of foamed ballast pad, and particularly relates to a polyurethane microporous foamed ballast pad and a preparation method thereof, which comprises the following components: an ISO component: aromatic diisocyanate, polytetrahydrofuran ether diol, polyether polyol and a retarder; a POLY component: polytetrahydrofuran ether diol, polymer polyol, 4,4'-methylenebis(2-chloroaniline), a heat-sensitive catalyst, dimethyl tin dimercaptoacetate, an alcohol amine catalyst, an amine catalyst, a foaming agent and a uniform foaming agent; the weight ratio of the ISO component and the POLY component is 100:90-205; the application can effectively improve the fatigue resistance and reduce the production cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of foamed ballast pad, and particularly relates to a polyurethane microcellular foamed ballast pad and a preparation method thereof. BACKGROUND

[0002] Heavy haul railway is widely valued by the world due to its large transport capacity, high efficiency, low energy consumption and low transportation cost, and has been internationally recognized as the direction of development of railway bulk cargo transportation. In particular, for a country like China with vast territory and uneven resource distribution, developing heavy haul railway transportation has broad market space and important strategic significance for rapidly improving transportation capacity, alleviating transport capacity bottleneck constraints, and improving comprehensive economic efficiency. However, heavy haul railway has large transport capacity, large axle load, large traction quality, and long load action time. The ballast bed of the ballasted track bridge and tunnel section is subjected to the double attack of the upper concrete track arrangement and the lower concrete rigid foundation, and the ballast is easy to break and dirty, the service life of the ballast bed is short, and the line ballast bed has many diseases, especially under the action of 30-ton axle load heavy haul train, the diseases will be more serious, the service life will be shorter, and more frequent maintenance and repair work needs to be invested.

[0003] Ballast pad is one of the effective technical measures to solve or alleviate the diseases of the ballast bed of the bridge and tunnel section, and especially the polyurethane microcellular foamed ballast pad has high bearing capacity and high fatigue performance. The laying of the polyurethane microcellular foamed ballast pad can improve the working state of the ballast bed of the bridge and tunnel section, especially in the structures or track structure forms that are completely different, such as the roadbed and tunnel, the roadbed and bridge, the roadbed and culvert, the cutting and embankment, and the ballasted track and non-ballasted track, thereby improving the service life of the line ballast bed. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a polyurethane microcellular foamed ballast pad and a preparation method thereof, which effectively improve the fatigue resistance and reduce the production cost.

[0005] The content of the present application includes a polyurethane microcellular foamed ballast pad, which comprises the following components,

[0006] The ISO component includes aromatic diisocyanate, polytetrahydrofuran ether diol, polyether polyol and retarder.

[0007] The POLY component includes polytetrahydrofuran ether diol, polymer polyol, 4,4'-methylenebis(2-chloroaniline), heat-sensitive catalyst, dimethyl tin dimercaptoacetate, alcohol amine catalyst, amine catalyst, foaming agent and foam stabilizer.

[0008] The weight ratio of the ISO component and the POLY component is 100:90-205, preferably 100:(140-170).

[0009] Optionally, in the ISO component, aromatic diisocyanate can be selected from TDI, MDI, NDI, preferably pure MDI, and can also be selected from pure MDI compounded with TDI or NDI.

[0010] The polytetramethylene ether glycol has a molecular weight of 2000 and a functionality of 2, and is preferably polytetramethylene ether glycol (PTMG2000). The polyether polyol is preferably polyether polyol (EP-330NG). The retarder is a protonic acid or a Lewis acid, and is preferably benzoyl chloride, n-alkylbenzenesulfonic acid, acetylacetone, ethyl acetoacetate, and inorganic acids such as phosphoric acid and hydrochloric acid, preferably phosphoric acid. The retarder is 0.01-0.5% by weight of the aromatic diisocyanate.

[0011] In the POLY component, the polytetramethylene ether glycol has a molecular weight of 1000 and a functionality of 2, the polyether polyol has a POP content of 36% and a functionality of 3, and the thermal sensitive catalyst is an acid-terminated amine salt or metal salt, preferably Yinkang SA20.

[0012] The alcohol amine catalyst is triethanolamine, diethanolamine, or methyldiethanolamine. The foaming agent is water. The foam stabilizer is selected from one or more of a siloxane-oxoalkylene copolymer and other organopolysiloxanes, and is preferably Yinkang 8123.

[0013] The amine catalyst is 1,3,5-triethyl-2,4-phenylenediamine, 1-methyl-3,5-di-ethyl-2,4-phenylenediamine, a mixture of 1-methyl-3,5-di-ethyl-2,4- and 2,6-phenylenediamine, and is preferably Yinkang 33LV.

[0014] In the embodiments of the present application, color paste can also be added, and the color paste is selected from a blend of black paste and blue paste.

[0015] In the POLY component, the water content is 0.1-3%, and is preferably 0.5%-0.9%.

[0016] The weight of 4,4'-methylenebis(2-chloroaniline) is not more than 35% of the total weight of the POLY component, and is preferably 8-12% of the total weight of the POLY component.

[0017] The weight ratio of the polytetramethylene ether glycol to the polyether polyol is 1:4-5.

[0018] The present application provides a preparation method of a polyurethane microcellular foamed ballast pad, wherein the temperature of the ISO component is controlled at 35-75°C, the temperature of the POLY component is controlled at 30-70°C, the ISO component and the POLY component are mixed and poured into a mold at 65-75°C, and after molding, the polyurethane microcellular foamed ballast pad is obtained after a period of time.

[0019] The period of time is not less than 24h.

[0020] ISO component temperature control at 70 DEG C, POLY component temperature control at 45 DEG C.

[0021] The present application has the advantages of simplifying the process, not needing to use a post-ripening process, directly placing for a period of time to achieve the effect that needs post-ripening in the conventional process, greatly reducing the production time and reducing the production cost.

[0022] The present application selects 4,4'-methylene di(2-chloroaniline) as a chain extender, and combines a heat-sensitive catalyst and dimethyl tin dimercaptoacetate, effectively reduces the static modulus change rate, and improves the fatigue resistance. Before the heat-sensitive catalyst is unblocked, the reaction of the catalytic raw material is slow, the flowability of the raw material after mixing is increased, the material reaction process is stable, the density uniformity of the foam body is good, and the fatigue performance of the product can be improved.

[0023] The present application provides a heavy haul railway polyurethane microcellular foamed ballast pad, which has the advantages of strong load bearing capacity and good fatigue performance. The polyurethane microcellular foamed ballast pad of the present application greatly buffers the rigid contact between the ballast and the foundation, greatly improves the anti-pulverization of the ballast, and prolongs the service life of the ballast pad; the polyurethane microcellular foamed ballast pad of the present application adopts a polyether system, has excellent stability, can withstand long-term weather resistance, provides long-term and stable static modulus, and maintains the stability of the stiffness of the heavy haul railway. The polyurethane microcellular foamed ballast pad of the present application can not only be suitable for heavy haul railways, but also can be suitable for high-speed railways by adjusting the foaming density and reducing the static modulus. DETAILED DESCRIPTION

[0024] Example 1

[0025] ISO component: xylene-based methane diisocyanate (MDI-100) 100 parts, polytetrahydrofuran ether diol (PTMG2000) 100 parts, polyether polyol (EP-330NG) 50 parts, phosphoric acid 0.03 parts.

[0026] POLY component: polytetrahydrofuran ether diol (PTMG1000) 100 parts, polymer POP36 / 28 polyol 450 parts, 4,4'-methylene di(2-chloroaniline) (MOCA) 50 parts, glycerol 0.5 parts, triethanolamine 0.2 parts, diethanolamine 0.2 parts, water 0.7 parts, catalyst 33LV (Yingchuang) 0.4g, catalyst SA20 (Yingchuang) 0.2g, catalyst dimethyl tin dimercaptoacetate 0.02 parts, foam stabilizer 8123 (Yingchuang) 2 parts, blue paste 1.5 parts.

[0027] Polyurethane ballast mat preparation: ISO component temperature was raised to 40°C, and POLY component temperature was raised to 38°C, according to ISO component and POLY component ratio 100:135 pouring into the mold temperature 70°C mold, one-time forming 20 min, polyurethane ballast mat after taking out the normal temperature for 72 h, detection of polyurethane ballast mat static modulus and fatigue performance.

[0028] Example 2

[0029] ISO: xylene-based methane diisocyanate (MDI-100) 60 parts, polytetrahydrofuran ether diol (PTMG2000) 100 parts, polyether polyol (EP-330NG) 50 parts, phosphoric acid 0.03 parts.

[0030] POLY: polytetrahydrofuran ether diol (PTMG1000) 50 parts, polymer POP36 / 28 polyol 200 parts, 4,4'-methylene di(2-chloroaniline) (MOCA) 30 parts, triethanolamine 0.2 parts, diethanolamine 0.2 parts, water 0.45 parts, catalyst 33LV (Yingchuang) 0.4g, catalyst SA20 (Yingchuang) 0.2g, catalyst dimethyl tin dithioglycolate 0.02 parts, foam stabilizer 8123 (Yingchuang) 2 parts, blue paste 0.7 parts.

[0031] Polyurethane ballast mat preparation: ISO component temperature was raised to 40°C, and POLY component temperature was raised to 38°C, according to ISO component and POLY component ratio 100:135 pouring into the mold temperature 70°C mold, one-time forming 20 min, polyurethane ballast mat after taking out the normal temperature for 72 h, detection of polyurethane ballast mat static modulus and fatigue performance.

[0032] Comparative example 1

[0033] ISO component: xylene-based methane diisocyanate (MDI-100) 100 parts, polytetrahydrofuran ether diol (PTMG2000) 100 parts, polyether polyol (EP-330NG) 50 parts, phosphoric acid 0.03 parts.

[0034] POLY component: polytetrahydrofuran ether diol (PTMG1000) 160 parts, polymer POP36 / 28 polyol 450 parts, 1,4-butanediol (BDO) 28 parts, glycerol 0.5 parts, triethanolamine 0.2 parts, diethanolamine 0.2 parts, water 0.7 parts, catalyst 33LV (Yingchuang) 0.4g, foam stabilizer 8123 (Yingchuang) 2 parts, blue paste 0.7 parts.

[0035] Other steps of polyurethane ballast mat preparation are the same as example 1.

[0036] Comparative example 2

[0037] ISO component: xylene-based methylene diisocyanate (MDI-100) 60 parts, polytetrahydrofuran ether diol (PTMG2000) 100 parts, polyether polyol (EP-330NG) 50 parts, phosphoric acid 0.03 parts.

[0038] POLY component: polytetrahydrofuran ether diol (PTMG1000) 100 parts, polymer POP36 / 28 polyol 200 parts, 4,4'-methylenebis(2-chloroaniline) (MOCA) 30 parts, triethanolamine 0.2 parts, diethanolamine 0.2 parts, water 0.45 parts, catalyst 33LV (Yingchuang) 0.4 g, foam stabilizer 8123 (Yingchuang) 2 parts, blue paste 0.7 parts.

[0039] Other steps of polyurethane ballast pad preparation are the same as example 2.

[0040] Comparative example 3

[0041] Compared with comparative example 2, the difference is that in the preparation of the polyurethane ballast pad, the one-time molding is 20 min, the normal temperature is placed for 72 h, and then it is placed in a 100℃ oven for post-curing for 10 h. After vulcanization is completed, it is placed at normal temperature for 7 days, and the static modulus and fatigue performance of the polyurethane microcellular foaming ballast pad are detected.

[0042] The densities of the above products are all 475±25kg / m 3 The performance of the products of the above examples and comparative examples is detected, and the data described in table 1 are obtained.

[0043] Table 1 performance detection table of different products

[0044]

[0045] The static modulus is the size of the sample 300mm*300mm*25mm, and the vertical loading is 22.5KN. After loading 1000 times, 10 cycles are selected from the last 100 cycles, and the difference ratio of the displacement value under the loading force value 1.8KN-9.0KN and the corresponding loading force is calculated. The detection method of static modulus and static modulus change rate is BS EN 17282:2020.

[0046] It should be understood by those skilled in the art that the above discussion of any of the embodiments is only exemplary and is not intended to imply that the scope of protection of the present application is limited to these examples; under the idea of the present application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of one or more embodiments of the present application as described above. In order to be brief, they are not provided in detail.

[0047] It is intended that the embodiments of the application herein disclosed meet all the written requirements of the patent statutes and come within the judicial doctrines of equivalents and will not be construed to be limited to the embodiments shown and described and by the keeping within the spirit and scope of the embodiments of the application.

Claims

1. A polyurethane microcellular foamed ballast mat, characterized by, Comprise the following components, ISO component: xylene-based methane diisocyanate MDI-100 100 parts, polytetrahydrofuran ether glycol PTMG2000 100 parts, polyether polyol EP-330NG 50 parts, phosphoric acid 0.03 parts; POLY component: polytetrahydrofuran ether glycol PTMG1000 100 parts, polymer POP36 / 28 polyol 450 parts, 4,4'-methylenebis(2-chloroaniline) MOCA 50 parts, glycerol 0.5 parts, triethanolamine 0.2 parts, diethanolamine 0.2 parts, water 0.7 parts, catalyst 33LV 0.4g, catalyst SA20 0.2g, catalyst dimethyltin dimercaptoacetate 0.02 parts, foam stabilizer 8123 2 parts, blue paste 1.5 parts; The weight ratio of the ISO component and the POLY component is 100:135; The ISO component is controlled at a temperature of 35-75℃, the POLY component is controlled at a temperature of 30-70℃, the ISO component and the POLY component are mixed and poured into a mold at 65-75℃, after molding, the placement time is not less than 24h, and a polyurethane microcellular foamed ballast pad is obtained.

2. A method of producing the polyurethane microcellular foamed ballast mat according to claim 1, characterized by, The ISO component is controlled at a temperature of 35-75℃, the POLY component is controlled at a temperature of 30-70℃, the ISO component and the POLY component are mixed and poured into a mold at 65-75℃, after molding, the placement time is not less than 24h, and a polyurethane microcellular foamed ballast pad is obtained.

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