High-fatigue-resistance polyurethane composition, method for preparing polyurethane foam molding curing ballast bed and application

Abstract

The invention relates to a high-fatigue-resistance polyurethane composition as well as a preparation method and application thereof, and the polyurethane composition comprises an isocyanate component and an isocyanate reactive component, the isocyanate reactive component comprises polyether polyol 1, polyether polyol 2, polymer polyol, a foaming agent, a flame retardant, a chain extender, a cross-linking agent, a surfactant, a catalyst and a pigment; the polyether polyol 1, the polyether polyol 2 and the polymer polyol are used together, and the polyurethane raw material has low-temperature non-crystallinity and fatigue resistance. The polyurethane composition provided by the invention simultaneously meets the performance requirements of polyurethane foam for a prefabricated curing ballast bed and the requirements of a cured ballast bed prefabricated member on anti-fatigue performance.

Description

Technical Field

[0001] The invention relates to the field of polyurethane materials, and in particular to a highly fatigue-resistant polyurethane composition and a method for preparing a polyurethane foaming molding and curing roadbed and application thereof. Background Art

[0002] Track is one of the main technical equipment of railway and the basis of driving. Compared with ballastless track, ballasted track has the advantages of good elasticity and low engineering investment. However, according to the current application status at home and abroad and related research and experiments, ballasted track is faced with many challenges such as ballast splashing, weak roadbed stability, easy ballast powdering, and rapid changes in track geometry when it is designed and operated at a speed of 300km / h and above. In recent years, in response to the needs of my country's railway construction and operation, China has begun to study polyurethane cured roadbed technology. The industry has developed a complete set of technologies with independent intellectual property rights, including high-speed railway polyurethane cured roadbed structure design, material preparation, construction technology and equipment, maintenance and repair.

[0003] The polyurethane solidified ballast bed is made of polyurethane foam material with good elasticity and buffering energy absorption. This ballast bed has both the integrity and low maintenance of ballastless ballast bed, and the good elasticity and easy maintenance of ballasted ballast bed. It has certain vibration reduction and noise reduction performance. In addition to being used in high-speed and heavy-load railways, it can also be used in urban rail transit such as subways and urban railways.

[0004] With the rapid development of my country's transportation industry, railway construction in high-altitude and cold areas is being carried out on a large scale. High-altitude and cold areas have climate characteristics such as large temperature difference between day and night, low minimum temperature, and strong ultraviolet radiation, which bring severe challenges to the construction of polyurethane cured roadbed.

[0005] Taking into account the construction process and performance requirements of cured ballast in high-altitude and cold areas, traditional polyurethane cured ballast materials must meet the following characteristics at the same time: ① no crystallization at low temperature; ② high physical and mechanical properties; ③ low water absorption; ④ high flame retardancy; ⑤ high aging resistance.

[0006] Patent CN202111529122.6 reports a polyurethane composition, a preparation method and an application thereof, wherein a first polyether polyol, a second polyether polyol and a flame-retardant amine compound constitute the polyurethane reaction components, and the composition has the technical characteristics of being a low-temperature (-20°C) liquid. The comprehensive performance of the polyurethane foam meets the performance requirements of polyurethane foam for prefabricated cured roadbeds.

[0007] However, compared with the performance indicators of cured roadbed prefabricated parts, the performance indicators of polyurethane foam still lack key performance indicators such as the penetration and bonding of polyurethane components between ballasts and fatigue resistance of prefabricated parts. In particular, during the use of prefabricated parts, they need to withstand repeated mechanical loads from trains. Fatigue resistance is a key performance parameter that determines whether prefabricated parts can serve safely and stably. Therefore, the China Railway Corporation emphasized the index requirements for the fatigue resistance of prefabricated parts in its relevant technical requirements.

[0008] In this context, the shortcomings of the patent CN202111529122.6 that relies solely on the low-temperature liquid polyether polyol solution to achieve the low-temperature non-crystallization goal of the polyurethane system are particularly prominent. It is a generally accepted view in the field of polymer materials that crystalline polymers will limit the expansion of microcracks due to the presence of crystalline regions, and therefore have higher fatigue resistance than amorphous polymers with similar molecular structures. It is precisely because the polyurethane reaction components in this patent scheme are amorphous that its fatigue resistance is poor. Even if the polyurethane foam finally obtains meets the performance index requirements, it is difficult to meet the technical requirements for fatigue resistance in the new standard.

[0009] Patents CN201410816023.X and CN201510556783.6 respectively report methods for preparing polyurethane foam materials for railway ballast and cured roadbed. Aiming at the relevant technical requirements of railway engineering, the design of a polyurethane composition system is proposed. However, compared with the technical requirements of polyurethane cured roadbed prefabricated parts in high-altitude and cold areas, especially the important indicator of fatigue resistance, there is a lack of targeted and effective solutions, and there is also a lack of testing on the fatigue resistance of materials prepared by this solution.

[0010] Patent CN202110126614.4 is aimed at polyurethane foam for railway solidified ballast and its preparation method under the conditions of large temperature difference, rain and ultraviolet erosion. Although this scheme meets the technical specifications in terms of the comprehensive performance of the final embodiment product, its preparation process requires the polyether polyol to be heated at 50-60°C for 6-12 hours to melt the crystalline raw materials. In other words, this scheme still adopts the traditional solidified ballast polyurethane composition system, and the polyether polyol crystallizes seriously at low temperatures. However, in the actual production and construction process, not only the raw materials need to be heated and melted, but also in the intermittent production process of prefabricated parts, each batch of production needs to be completed. The intricate pipelines of the equipment need to be heated and cleaned, otherwise once the external temperature drops, the polyether polyols remaining in the equipment pipelines will crystallize and block the pipelines. Therefore, using traditional crystalline polyether polyols, even if the final product can meet the performance requirements, its processing and preparation costs and cycles are still very high. Summary of the invention

[0011] In view of the technical requirements for low-temperature non-crystallization, physical and mechanical properties, water absorption, flame retardancy, aging resistance, and especially fatigue resistance of polyurethane materials for polyurethane cured roadbed prefabricated parts in high-altitude and cold areas, and the serious defects of the prior art, the present invention provides a highly fatigue-resistant polyurethane composition.

[0012] Another object of the present invention is to provide a method for preparing a polyurethane foaming and curing ballast bed by using the highly fatigue-resistant polyurethane composition.

[0013] Another object of the present invention is to provide an application of the polyurethane foaming molding and curing roadbed.

[0014] To achieve the above invention object, the technical solution of the present invention is as follows:

[0015] A highly fatigue-resistant polyurethane composition is obtained by reacting an isocyanate component and an isocyanate-reactive component, wherein the isocyanate-reactive component comprises: polyether polyol 1, polyether polyol 2, polymer polyol, foaming agent, flame retardant, chain extender, crosslinking agent, surfactant, catalyst, and pigment; wherein

[0016] The polyether polyol 1 has an average functionality of 2 to 4.5, such as 2, 2.5, 3, 3.5, 4, 4.5, etc., preferably 2.5 to 3.5, and a hydroxyl value of 10 to 200 mgKOH / g, such as 10 mgKOH / g, 15

[0017] : 1.5-2.0 wt % propylene oxide, 2.5-3.0 wt % propylene oxide, 3.5-4.0 wt % propylene oxide, 4.5-5.0 wt % propylene oxide, 5.5-6.0 wt % propylene oxide, 6.5-7.0 wt % propylene oxide, 7.5-8.0 wt % propylene oxide, 8.5-9.0 wt % propylene oxide, etc., preferably 2.0-4.0 wt % propylene oxide, 2.5-3.0 wt % propylene oxide, etc., preferably 2.0-4.0 wt % propylene oxide, 3.5-5.0 wt % propylene oxide, etc.

[0018] The polyether polyol 2 has an average functionality of 1.5 to 3, such as 1.5, 2, 2.5, 3, etc., preferably 1.5 to 2.5, and a hydroxyl value of 10 to 200 mgKOH / g, such as 10 mgKOH / g, 15 mgKOH / g, 20 mgKOH / g, 25 mgKOH / g, 30 mgKOH / g, 35 mgKOH / g, 40 mgKOH / g, 50 mgKOH / g, 60 mgKOH / g, 70 mgKOH / g, 80 mgKOH OH / g, 90mgKOH / g, 100mgKOH / g, 130mgKOH / g, 150mgKOH / g, 180mgKOH / g, 200mgKOH / g, etc., preferably 20-40mgKOH / g, obtained by reacting ethylene oxide and propylene oxide, with an ethylene oxide content of 5-10wt%, such as 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc., based on the total mass of propylene oxide and ethylene oxide as 100%;

[0019] The polymer polyol, i.e., the graft copolymer polyether polyol, has an average functionality of 2 to 4.5, such as 2, 2.5, 3, 3.5, 4, 4.5, etc., preferably 3, a hydroxyl value of 15 to 50 mgKOH / g, such as 15 mgKOH / g, 20 mgKOH / g, 25 mgKOH / g, 30 mgKOH / g, 35 mgKOH / g, 40 mgKOH / g, 45 mgKOH / g, 50 mgKOH / g, etc., preferably 20 to 40 mgKOH / g, and a solid content of 20 to 50 wt%, such as 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, etc., preferably 25 to 45 wt%;

[0020] Based on the total mass of the isocyanate-reactive components, the amount of polyether polyol 1 (A) in the isocyanate-reactive components is 30% to 50%, for example, 30%, 31%, 33%, 35%, 38%, 40%, 41%, 43%, 45%, 48%, 50%, etc., the amount of polyether polyol 2 (B) is 20% to 45%, for example, 20%, 21%, 22%, 23%, 24%, 25%, 28%, 30%, 31%, 33%, 35%, 38%, 40%, 41%, 42%, 43%, 44%, 45%, etc., and the amount of polymer polyol (C) is 9% to 10%, for example, 9%, 9.1%, 9.3%, 9.5%, 9.6%, 9.8%, 9.9%, 10%, etc.

[0021] In a preferred embodiment, the amount of polyether polyol 1 A, the amount of polyether polyol 2 B, and the amount of polymer polyol C in the isocyanate reactive component, A, B, and C all satisfy the following relationship:

[0022]

[0023] In some specific embodiments, the isocyanate component refers to a class of compounds having an isocyanate group, examples of which include but are not limited to toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), naphthalene diisocyanate (DI), p-phenylene diisocyanate (PPDI), 1,4-cyclohexane diisocyanate (CHDI), xylene diisocyanate (XDI), cyclohexane dimethylene diisocyanate (XDI), trimethyl-1,6-hexamethylene diisocyanate (TMHDI), tetramethyl meta-xylene diisocyanate (TMXDI), norbornane diisocyanate (NBDI), dimethyl diphenyl diisocyanate (TODI), methylcyclohexyl diisocyanate (HTDI), etc., as well as prepolymers, modified products, polymers, etc. of such monomers. Such isocyanate compounds can be used alone or in combination. Preferably, the NCO content of the isocyanate component is 12 to 25wt%, for example 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt% and the like, preferably 17wt%.

[0024] In some specific embodiments, the polyether polyol 1 is a class of compounds initiated by polyols and polymerized by alkylene oxide. Examples of initiators include but are not limited to ethylene glycol, propylene glycol, 1,4-butanediol, dipropylene glycol, diethylene glycol, triethylene glycol, bisphenol A, glycerol, trimethylolpropane, diethanolamine, triethanolamine, ethylenediamine, toluene diamine, pentaerythritol, sorbitol, xylitol, sucrose or mixtures thereof. The alkylene oxide monomer may be block addition or random addition, preferably block addition, and more preferably an average functionality of 3, propylene oxide polymerization, and ethylene oxide block addition at the end.

[0025] In some specific embodiments, the polyether polyol 2 is a class of compounds formed by starting with a polyol and polymerizing an alkylene oxide. Examples of the initiator include but are not limited to ethylene glycol, propylene glycol, 1,4-butanediol, dipropylene glycol, diethylene glycol, triethylene glycol, bisphenol A, glycerol, trimethylolpropane, diethanolamine, triethanolamine, ethylenediamine, toluenediamine, pentaerythritol or a mixture thereof. The alkylene oxide monomer may be block-added or randomly added, preferably with an average functionality of 2, and the alkylene oxide monomer may be randomly added.

[0026] In some specific embodiments, the polymer polyol refers to a type of graft copolymer polyol obtained by reacting a polyether polyol and a vinyl monomer, wherein the polyether polyol may be polyoxyethylene polyol, polyoxypropylene polyol, polyoxyethylene-oxypropylene copolymer polyol, etc. commonly used in the art, and the vinyl monomer may be acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl acrylate, alkyl acrylate, etc., preferably acrylonitrile and / or styrene.

[0027] In some specific embodiments, the foaming agent can be selected from physical foaming agents, chemical foaming agents, etc. commonly used in the art, including but not limited to water, monochlorodifluoromethane, monochloromonofluoromethane, dichlorodifluoromethane, trichlorofluoromethane, butane, pentane, cyclopentane, hexane, cyclohexane, heptane, air, CO2 and N2, preferably water.

[0028] In some specific embodiments, examples of the flame retardant include, but are not limited to, halogenated phosphate flame retardants, phosphate flame retardants, halogenated hydrocarbons and other halogen-containing flame retardants, melamine and its salts, reactive flame retardants, inorganic flame retardants, etc. Such flame retardants can be used alone or in combination. Preferably, the flame retardant is selected from a liquid flame retardant having a viscosity of 40 to 800 mpa.s at 25°C; further preferably, the flame retardant has a viscosity of 60 to 400 mpa.s at 25°C; further preferably, the flame retardant is composed of flame retardant 1 and flame retardant 2, wherein flame retardant 1 refers to a flame retardant itself that can participate in the reaction, so that the polyurethane molecules obtained by the reaction have a flame retardant function and have little effect on material properties, and examples of flame retardant 1 include but are not limited to tri(dipropylene glycol) phosphite, N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, N,N-bis(2-hydroxyethyl)aminomethylphosphonic acid dimethyl ester, FR212 (produced by Wanhua Chemical Company), etc. The flame retardant 2 refers to a type of flame retardant that can have a flame retardant effect but does not participate in the reaction. Examples of the flame retardant 2 include, but are not limited to, tris(2-chloroethyl)phosphate, (2-chloropropyl)phosphate, di(3-bromo-2,2-dimethylpropyl)phosphate, dimethyl methylphosphate, diethyl ethylphosphate, dimethyl propylphosphate, triethyl phosphate, triphenyl phosphate, tricresyl phosphate, etc. The flame retardant of the present invention enables the polyurethane composition to have a good flame retardant effect, and at the same time has a lower viscosity at room temperature, thereby improving the moldability of the polyurethane composition and the reinforcing material.

[0029] In some specific embodiments, the chain extender can be a chain extender commonly used in the art, such as diols, diamines, diphenols, etc. Examples include but are not limited to ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol, cyclohexanediol, methylamine, ethylamine, hydrogenated bisphenol A, hydroquinone, etc. Such chain extenders can be used alone or in combination.

[0030] In some specific embodiments, the cross-linking agent can be a cross-linking agent commonly used in the art, such as polyols, polyamines, etc. Examples include but are not limited to trimethylolpropane, propylene glycol, pentaerythritol, diethanolamine, triethanolamine, ethylenediamine, phenylenediamine, sorbitol, etc. Such cross-linking agents can be used alone or in combination.

[0031] In some specific embodiments, the surfactant, examples of which include but are not limited to, a main structure of a polysiloxane-oxyalkylene block copolymer, etc. Such surfactants can be used alone or in combination.

[0032] In some specific embodiments, the catalyst refers to a class of compounds having catalytic activity towards isocyanate and active hydrogen atoms, examples of which include but are not limited to amine catalysts, organometallic catalysts, etc. Such catalysts can be used alone or in combination.

[0033] In some specific embodiments, the isocyanate reactive component may also contain other commonly used additives in the art, including but not limited to coupling agents, color pastes, fillers, smoke suppressants, dyes, antistatic agents, antioxidants, light stabilizers, diluents, surface wetting agents, leveling agents, thixotropic agents, viscosity reducers, plasticizers, etc.

[0034] In a specific embodiment, the molar ratio of isocyanate groups in the isocyanate component to active hydrogen atoms in the isocyanate reactive component is 95-105:100, for example, 95:100, 100:100, 105:100, etc.

[0035] In a preferred embodiment, based on the total mass of the isocyanate reactive component, the isocyanate reactive component comprises:

[0036] The amount of polyether polyol 1 is 30-50%, for example, 30%, 33%, 35%, 37%, 40%, 41%, 43%, 45%, 46%, 48%, 50%, etc.;

[0037] The amount of polyether polyol 2 is 20-45%, for example, 20%, 21%, 22%, 23%, 24%, 25%, 28%, 30%, 33%, 35%, 37%, 40%, 41%, 43%, 45%, etc.;

[0038] The amount of polymer polyol is 9-10%, for example, 9%, 9.1%, 9.2%, 9.3%, 9.4%, 9.5%, 9.6%, 9.7%, 9.8%, 9.9%, 10%, etc.;

[0039] The amount of foaming agent is 0.8-1.3%, for example, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, etc.;

[0040] The amount of flame retardant is 8-25%, for example, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc.;

[0041] The amount of chain extender is 1-5%, for example, 1%, 2%, 3%, 4%, 5%, etc.;

[0042] The amount of the cross-linking agent is 1-3%, for example, 1%, 2%, 3%, etc.;

[0043] The amount of surfactant used is 0.3-0.8%, such as 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.;

[0044] The amount of catalyst is 0.5-1.2%, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, etc.;

[0045] The amount of pigment used is 0.05-0.2%, for example 0.05%, 0.1%, 0.15%, 0.2%, etc.

[0046] In a preferred embodiment, the molar ratio of isocyanate groups in the isocyanate component to active hydrogen atoms in the isocyanate reactive component in the polyurethane composition is 95-105:100, for example, 95:100, 98:100, 100:100, 101:100, 105:100, etc.

[0047] The polyurethane composition comprising the polyether polyol 1, polyether polyol 2, polymer polyol, foaming agent, flame retardant, chain extender, crosslinking agent, surfactant, catalyst, pigment and isocyanate component is easy to operate and store, highly flame retardant, has excellent mechanical properties and low water absorption, and has very excellent aging resistance and fatigue resistance when used to prepare polyurethane foam, and can be used for large-scale production of polyurethane cured roadbeds.

[0048] According to the technical requirements of polyurethane cured roadbed in high altitude and cold areas with reliable fatigue resistance, low temperature non-crystallization, flame retardancy, excellent physical properties, low water absorption and high aging resistance, polyether polyol 1 and polyether polyol 2 are used to ensure the low temperature non-crystallization of polyurethane foam, and the introduction of polymer polyols with special side chain structures and their strong non-covalent interactions can significantly improve the fatigue resistance of the cured roadbed. It can effectively improve the service life of polyurethane cured roadbed, reduce the cost in the preparation process, simplify the construction process, and realize economical and reliable large-scale mass production of polyurethane cured roadbed technology.

[0049] However, there are many contradictions in the performance requirements of polyurethane cured roadbed, such as low temperature non-crystallization and fatigue resistance, high elongation and low compression deformation, hard foam level water absorption and soft foam level compression. In order to effectively avoid a large number of trial and error tests, the present invention limits the amount of polyether polyol 1 (A) to

[0050] 30%~50%, polyether polyol 2 dosage (B) 20%~45%, polymer polyol dosage (C)

[0051] 9% to 10%, preferably satisfying the following relationship at the same time:

[0052]

[0053] The result is a polyurethane cured roadbed that can be used in high-altitude and cold areas and has reliable fatigue resistance, low-temperature non-crystallization, flame retardancy, excellent physical properties, low water absorption and high aging resistance.

[0054] In the above formula, A and B are calculated without %. For example, when A is 50%, 50 is directly substituted into the formula. When B is 25%, 25 is directly substituted into the formula. The final calculated content of C is 10.18, that is, the content of C is 10.18%.

[0055] In another aspect of the present invention, a method for preparing polyurethane foam using the polyurethane composition comprises the following steps:

[0056] Step 1, at 10-60° C., respectively, the isocyanate component is mixed and stirred evenly for later use, and the isocyanate reactive component is mixed and stirred evenly for later use;

[0057] Step 2: at 10-60° C., the isocyanate component and the isocyanate reactive component are mixed evenly by equipment and then injected into a mold for reaction. After the reaction is completed, the mold is opened to obtain a polyurethane foam.

[0058] The filling density of polyurethane foam is preferably 275 to 295 kg / m 3The pouring pressure is preferably 130 to 170 bar, the mold temperature is preferably 10 to 60°C, and the holding time is preferably 50 to 90 minutes.

[0059] On the other hand, a method for preparing a polyurethane foaming molding and curing ballast bed using the aforementioned polyurethane composition comprises the following steps:

[0060] Step 1, at 10-60° C., respectively, the isocyanate component is mixed and stirred evenly for later use, and the isocyanate reactive component is mixed and stirred evenly for later use;

[0061] Step 2: at 10-60° C., the isocyanate component and the isocyanate reactive component are mixed evenly by equipment and then directly injected into the railway ballast or into a mold containing the ballast. After the reaction is completed, the polyurethane foaming molded and cured ballast bed is obtained directly or by opening the mold.

[0062] The method of directly injecting railway ballast in step 2 is construction type, and the method of injecting the molding with ballast is prefabrication type. The temperature of ballast and mold is 10-60°C, the aging time of construction type is preferably 4-6 hours, and the holding time of prefabrication type is preferably 50-90 minutes. The ballast is in accordance with the railway crushed stone ballast standard TB / T 2140, and the ballast bulk density is preferably 2.5-3.1g / cm 3 The preferred filling porosity of prefabricated ballast is 39%.

[0063] The specific components involved in the polyurethane composition of the present invention, such as polyols, additives, etc., can be used alone or in combination unless otherwise specified. In addition, the raw materials, processes, methods, parameters, etc. required for the preparation of each component, the parts not described or recorded can refer to the commonly used technology in the field, and will not affect the implementation of the present invention, such as the preparation of polyether polyols, the preparation of catalysts, etc.

[0064] The "hydroxyl value" in the present invention, unless otherwise specified, refers to the average hydroxyl value of the component.

[0065] The existing patented technology uses non-crystallizing polyether polyol components to achieve non-crystallization and non-precipitation of polyurethane foam raw materials in high-altitude and cold areas, so as to improve the processability of polyurethane cured roadbed in these areas. However, the existing technology ignores the obvious deterioration effect of non-crystallizing polyether polyol components on the fatigue resistance of cured roadbed, and it is difficult to meet the requirements of fatigue resistance of polyurethane cured roadbed in high-altitude and cold areas.

[0066] Traditional polyurethane foam preparation technology seeks the best process parameters through large-scale trial and error of formulas. Faced with the complex performance requirements of polyurethane cured roadbeds in high-altitude and cold regions described in the present invention, it is difficult to understand the rules of various process parameters based on the formula design from the perspective of theoretical analysis, and a large number of exploratory tests are required. For example, in the performance requirements of polyurethane cured roadbeds, low-temperature non-crystallization and fatigue resistance, high elongation and low compression deformation, hard foam level water absorption and soft foam level compression are all contradictions in performance and formula technology.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] 1) The present invention provides a polyurethane composition, which is applied to polyurethane cured roadbed in high-altitude and cold areas, and has reliable fatigue resistance, low-temperature non-crystallization, flame retardancy, excellent physical properties, low water absorption and high aging resistance. The low-temperature non-crystallization of polyurethane foam is guaranteed by the introduction of polymer polyols with special side chain structures, and the fatigue resistance of the cured roadbed can be significantly improved by utilizing its strong non-covalent interaction. It can effectively improve the service life of the polyurethane cured roadbed, reduce the cost in the preparation process, simplify the construction process, and enable the polyurethane cured roadbed technology to achieve economical and reliable large-scale mass production.

[0069] 2) The polyurethane foam of the present invention has elastomer-level stretching and tearing and soft foam-level compression, so that it has good extension and compression deformation performance. At the same time, its hard foam-level water absorption capacity solves the problem of high water absorption rate of open-cell polyurethane, and further increases the service life of the prepared polyurethane cured roadbed. DETAILED DESCRIPTION

[0070] Some embodiments are listed below to help the public better understand the technical solutions of the present invention.

[0071] The raw materials used in the embodiments and comparative examples are as follows:

[0072] Isocyanate component 1, WANNATE 8605, NCO content 17.1wt%, viscosity 800mPa·s at 25°C, Wanhua Chemical;

[0073] Isocyanate component 2, WANNATE 8609, NCO content 19.8wt%, viscosity 330mPa·s at 25°C, Wanhua Chemical;

[0074] Isocyanate component 3, WANNATE PM200, NCO content 31.2wt%, viscosity 250mPa·s at 25°C, Wanhua Chemical;

[0075] Polyether polyol 1-1, trimethylolpropane-initiated, propylene oxide polymerized, ethylene oxide terminal block added, ethylene oxide content 25wt%, hydroxyl value 20mgKOH / g;

[0076] Polyether polyol 1-2, glycerol initiator, propylene oxide polymerization, ethylene oxide terminal block addition, ethylene oxide content 15wt%, hydroxyl value 28mgKOH / g;

[0077] Polyether polyol 1-3, glycerol initiator, propylene oxide polymerization, ethylene oxide terminal block addition, ethylene oxide content 10wt%, hydroxyl value 40mgKOH / g;

[0078] Polyether polyol 2-1, diethylene glycol starting, propylene oxide and ethylene oxide random copolymerization, ethylene oxide content 10wt%, hydroxyl value 20mgKOH / g;

[0079] Polyether polyol 2-2, starting with ethylene glycol, random copolymerization of propylene oxide and ethylene oxide, ethylene oxide content 5wt%, hydroxyl value 40mgKOH / g;

[0080] Polyether polyol 2-3, starting with propylene glycol, random copolymerization of propylene oxide and ethylene oxide, ethylene oxide content 6wt%, hydroxyl value 35mgKOH / g;

[0081] Polymer polyol 1-1, glycerol-based, hydroxyl value 20 mgKOH / g, solid content 25 wt%;

[0082] Polymer polyol 1-2, trimethylolpropane starting material, hydroxyl value 40 mgKOH / g, solid content 30 wt%;

[0083] Polymer polyol 1-3, glycerol-based, hydroxyl value 28 mgKOH / g, solid content 45 wt%;

[0084] Polyether polyol 3, glycerol-based, hydroxyl value 35 mgKOH / g, polymerization of propylene oxide and ethylene oxide, ethylene oxide content 10%, based on the total mass of propylene oxide and ethylene oxide;

[0085] Polyether polyol 4, glycerol-based, hydroxyl value 28 mgKOH / g, polymerization of propylene oxide and ethylene oxide, ethylene oxide content 15%, based on the total mass of propylene oxide and ethylene oxide;

[0086] Polyether polyol 5, glycerol-based, hydroxyl value 45 mgKOH / g, polymerization of propylene oxide and ethylene oxide, ethylene oxide content 20%, based on the total mass of propylene oxide and ethylene oxide;

[0087] Polyether polyol 6, starting with propylene glycol, hydroxyl value of 28 mgKOH / g, polymerization of propylene oxide and ethylene oxide, ethylene oxide content of 15%, based on the total mass of propylene oxide and ethylene oxide;

[0088] Polyether polyol 7, starting with propylene glycol, hydroxyl value of 40 mgKOH / g, polymerization of propylene oxide and ethylene oxide, ethylene oxide content of 20%, based on the total mass of propylene oxide and ethylene oxide;

[0089] Polyether polyol 8, starting with propylene glycol, hydroxyl value of 20 mgKOH / g, polymerization of propylene oxide and ethylene oxide, ethylene oxide content of 10%, based on the total mass of propylene oxide and ethylene oxide;

[0090] Polymer polyol 2, glycerol starting, 21 mgKOH / g, polymerization of propylene oxide, ethylene oxide, acrylonitrile, and styrene; solid content 40%, based on the total mass of propylene oxide, ethylene oxide, acrylonitrile, and styrene;

[0091] Polymer polyol 3, glycerol starting, 24.5 mgKOH / g, polymerization of propylene oxide, ethylene oxide, acrylonitrile, and styrene; solid content 30%, based on the total mass of propylene oxide, ethylene oxide, acrylonitrile, and styrene;

[0092] Polymer polyol 4, glycerol starting, 28 mgKOH / g, polymerization of propylene oxide, ethylene oxide, acrylonitrile, and styrene; solid content 20%, based on the total mass of propylene oxide, ethylene oxide, acrylonitrile, and styrene;

[0093] Foaming agent, water;

[0094] Flame retardant 1, FR212, Wanhua Chemical;

[0095] Flame retardant 2, A710, Hemu New Materials;

[0096] The flame retardant amine compound, the preparation method is as follows:

[0097] Select FR212 and ethylenediamine (industrial grade), add solid ruthenium nickel bimetallic catalyst to the equipment, the molar ratio of FR212 and ethylenediamine is 1:2, and stir in the reaction equipment under nitrogen protection. After the obtained solution is reacted at 120°C for 24 hours, the solution is cooled to room temperature, and the ruthenium nickel bimetallic catalyst is separated by filtration. The filtrate is extracted with ethyl acetate three times, and the combined organic layer is washed with saturated sodium chloride solution and dried with anhydrous magnesium sulfate to obtain a flame retardant amine compound. According to the infrared spectrum test results, the total amine content is 2.79meq / g, the primary amine content is 1.44meq / g, the secondary amine content is 1.35meq / g, and the tertiary amine content is 0.00meq / g.

[0098] Chain extender 1, ethylene glycol;

[0099] Chain extender 2,1,4-butanediol;

[0100] Cross-linking agent, glycerol;

[0101] Surfactant 1, WANALYST BM029, Wanhua Chemical;

[0102] Surfactant 2, WANALYST BM031, Wanhua Chemical;

[0103] Surfactant 3, B8002, Evonik;

[0104] Surfactant 4, B8715, Evonik;

[0105] Catalyst 1, WANALYST KC121, Wanhua Chemical;

[0106] Catalyst 2, WANALYST KC152, Wanhua Chemical;

[0107] Catalyst 3, BICAT8106, Leading Chemical;

[0108] Pigments, Bomax Corporation;

[0109] Preparation method of polyurethane foam samples of embodiments and comparative examples:

[0110] Step 1, at 30° C., respectively, mixing and stirring the isocyanate component and the isocyanate reactive component for uniform use;

[0111] Step 2: at 30°C, the isocyanate component and the isocyanate reactive component are mixed evenly by equipment and then injected into the mold for reaction. After the reaction is completed, the mold is opened to obtain polyurethane foam. The filling density of the polyurethane foam is 285kg / m 3 , the pouring pressure is 150 bar, the mold temperature is 50°C, and the holding time is 60 minutes.

[0112] Preparation method of polyurethane foaming and curing roadbed:

[0113] Step 1, at 30° C., respectively, mixing and stirring the isocyanate component and the isocyanate reactive component for uniform use;

[0114] Step 2: at 30°C, the isocyanate component and the isocyanate reactive component are mixed evenly by equipment and then injected into a mold containing ballast. After the reaction is completed, the polyurethane foaming molding and curing ballast bed is obtained directly or by opening the mold. The ballast bulk density is 2.8g / cm 3, the ballast filling porosity is 39%, the pouring pressure is 150 bar, the mold temperature is 50 ° C, and the holding time is 80 minutes.

[0115] The raw materials used in the examples and comparative examples are listed in Table 1 and Table 2.

[0116] Table 1 (parts by mass)

[0117]

[0118] Table 2 (parts by mass)

[0119]

[0120]

[0121] Performance Testing

[0122] The standard for prefabricated solidified ballast is issued by China Railway Corporation, which includes the performance requirements of polyurethane foam for prefabricated solidified ballast, as shown in Table 3.

[0123] Table 3 Performance requirements of polyurethane foam for prefabricated cured ballast

[0124] Test items unit Technical requirements Foam density <![CDATA[Kg / m 3 ]]> 285±10 10% compression strength kPa ≥25 Tensile Strength MPa ≥0.4 Elongation at break ％ ≥200 Tear strength N / m ≥800 Compression set ％ ≤10 Oxygen Index ％ ≥26 Dry heat aging retention rate ％ ≥80 Humidity and heat aging retention rate ％ ≥80 UV aging retention rate ％ ≥80 Low temperature recovery ability ％ ≥80 Water absorption (4d) ％ ≤25 <![CDATA[0~3×10 6 Cumulative deformation times]]> mm ≤3 <![CDATA[1×10 6 ~3×10 6 Cumulative deformation times]]> mm ≤0.5 <![CDATA[0~3×10 6 Substatic modulus change rate]]> ％ ≤50 <![CDATA[1×10 6 ~3×10 6 Static modulus change rate]]> ％ ≤15

[0125] The polyurethane compositions described in Examples 1-7 and Comparative Examples 1-8 were tested as follows:

[0126] (1) Foam density test standard: GB / T 6343;

[0127] (2) Compression strength test standard: GB / T 10807;

[0128] (3) Oxygen index test standard: GB / T 2406.2;

[0129] (4) Compression set test standard: GB / T 6669;

[0130] (5) Water absorption test standard: GB / T 8810;

[0131] (6) Dry heat aging and wet heat aging test standards: GB / T 9640;

[0132] (7) UV aging test standard: GB / T 16422;

[0133] (8) Tear strength test standard: GB / T 10808;

[0134] (9) Tensile strength test standard: GB / T 6344;

[0135] (10) Elongation at break test standard: GB / T 6344;

[0136] (11) Low temperature performance recovery test: The low temperature performance recovery test specimen is placed at -20℃ for 168 hours and then at 20℃ for 4 hours. The tensile strength and elongation at break are tested according to GB / T 6344. The skin of the specimen should be removed.

[0137] The test results are summarized in Tables 4 and 5.

[0138] Table 4 Performance of the embodiments

[0139]

[0140]

[0141] According to the data in Table 4, the polyurethane composition of the present invention meets the requirements of polyurethane for prefabricated cured roadbed, and the foam density of the polyurethane composition of the present invention is 285±10Kg / m 3 Within the range, 10% compression strength is above 47MPa, tensile strength is above 540kPa, elongation at break is above 206%, tear strength is above 842N / m, compression permanent deformation is below 10%, dry heat aging retention rate is above 90%, wet heat aging retention rate is above 92%, low temperature recovery capacity is above 92%, water absorption rate is within 15%, oxygen index is above 26%, 0~3×10 6 The cumulative deformation is less than 2.8 mm, 1×10 6 ~3×10 6 The cumulative deformation is less than 0.40 mm, 0~3×10 6 The static modulus change rate is below 45%, 1×10 6 ~3×10 6 The static modulus change rate is less than 14%.

[0142] In addition, the polyurethane composition of the present invention does not contain any room temperature solid polyols and solid flame retardants, does not precipitate or crystallize at room temperature, has good storage stability and process operability, and has excellent compatibility between the isocyanate component and the isocyanate reactive component. The foam prepared from the polyurethane composition has excellent mechanical strength, toughness, deformation resistance, aging resistance and flame retardancy, and can simultaneously meet the comprehensive requirements of mechanical properties, flame retardancy and water absorption of polyurethane foam for prefabricated cured ballast issued by China Railway Corporation.

[0143] Table 5 Comparative Examples Performance

[0144]

[0145]

[0146] Table 5 shows the performance test results of each comparative example. Analysis of comparative examples 1-8 shows that although the foam density, 10% compression strength, tensile strength, elongation at break, tear strength, compression permanent deformation, dry heat aging, wet heat aging, low temperature recovery resistance, water absorption rate (4d), and oxygen index meet the requirements of prefabricated cured ballast polyurethane, ... 6 times and 1×10 6 ~3×10 6 times cumulative deformation and 0~3×10 6 times and 1×10 6 ~3×10 6 The sub-static modulus change rate does not fully meet the requirements of polyurethane for prefabricated cured ballast.

[0147] When the existing patented technologies CN201410816023.X (Example 1), CN201510556783.6 (Example 1) and CN202110126614.4 (Example 1) do not have a raw material preheating step, the components are very easy to crystallize, and even the raw materials cannot be mixed, resulting in the inability to form the product.

[0148] The present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A highly fatigue-resistant polyurethane composition, characterized in that: The isocyanate-reactive component is obtained by reacting an isocyanate component and an isocyanate-reactive component, wherein the isocyanate-reactive component comprises: polyether polyol 1, polyether polyol 2, polymer polyol, foaming agent, flame retardant, chain extender, crosslinking agent, surfactant, catalyst, and pigment; wherein: The polyether polyol 1 has an average functionality of 2 to 4.5, preferably 2.5 to 3.5, a hydroxyl value of 10 to 200 mgKOH / g, preferably 20 to 40 mgKOH / g, and is obtained by reacting ethylene oxide and propylene oxide, and has an ethylene oxide content of 10 to 25 wt%, based on the total mass of propylene oxide and ethylene oxide being 100%; The polyether polyol 2 has an average functionality of 1.5 to 3, preferably 1.5 to 2.5, a hydroxyl value of 10 to 200 mgKOH / g, preferably 20 to 40 mgKOH / g, and is obtained by reacting ethylene oxide and propylene oxide, and has an ethylene oxide content of 5 to 10 wt%, based on the total mass of propylene oxide and ethylene oxide being 100%; The polymer polyol, i.e., graft copolymer polyether polyol, has an average functionality of 2 to 4.5, preferably 3, a hydroxyl value of 15 to 50 mgKOH / g, preferably 20 to 40 mgKOH / g, and a solid content of 20 to 50 wt%, preferably 25 to 45 wt%; Based on the total mass of the isocyanate reactive components, the amount of polyether polyol 1 (A) in the isocyanate reactive components accounts for 30% to 50%, the amount of polyether polyol 2 (B) accounts for 20% to 45%, and the amount of polymer polyol (C) accounts for 9% to 10%.

2. The highly fatigue-resistant polyurethane composition according to claim 1, characterized in that: The isocyanate reactive component includes an amount A of polyether polyol 1, an amount B of polyether polyol 2, and an amount C of polymer polyol, wherein A, B, and C satisfy the following relationship:

3. The highly fatigue-resistant polyurethane composition according to claim 1 or 2, characterized in that: The polyether polyol 1 is prepared by starting with a polyol and polymerizing an alkylene oxide, wherein the initiator used is selected from at least one of ethylene glycol, propylene glycol, 1,4-butanediol, dipropylene glycol, diethylene glycol, triethylene glycol, bisphenol A, glycerol, trimethylolpropane, diethanolamine, triethanolamine, ethylenediamine, toluenediamine, pentaerythritol, sorbitol, xylitol, and sucrose, and the alkylene oxide monomer is a block addition or random addition alkylene oxide monomer, preferably a block addition, and more preferably propylene oxide polymerization, and ethylene oxide block addition is performed at the end.

4. The highly fatigue-resistant polyurethane composition according to claim 1 or 2, characterized in that: The polyether polyol 2 is prepared by starting with a polyol and polymerizing an alkylene oxide, and the initiator used is at least one selected from ethylene glycol, propylene glycol, 1,4-butanediol, dipropylene glycol, diethylene glycol, triethylene glycol, bisphenol A, glycerol, trimethylolpropane, diethanolamine, triethanolamine, ethylenediamine, toluenediamine, and pentaerythritol, and the alkylene oxide monomer is a block addition or random addition alkylene oxide monomer, preferably a random addition.

5. The highly fatigue-resistant polyurethane composition according to claim 1 or 2, characterized in that: The polymer polyol is a graft copolymer polyol obtained by reacting a polyether polyol and a vinyl monomer; Preferably, the polyether polyol is selected from at least one of polyethylene oxide polyol, polypropylene oxide polyol and polyethylene oxide-propylene oxide copolymer polyol; and / or The vinyl monomer is selected from at least one of acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl acrylate and alkyl acrylate, preferably acrylonitrile and / or styrene.

6. The highly fatigue-resistant polyurethane composition according to claim 1 or 2, characterized in that: The foaming agent is a physical foaming agent or a chemical foaming agent; preferably, one or more selected from water, monochlorodifluoromethane, monochloromonofluoromethane, dichlorodifluoromethane, trichlorofluoromethane, butane, pentane, cyclopentane, hexane, cyclohexane, heptane, air, CO2 and N2, preferably water; and / or The flame retardant is selected from at least one of halogenated phosphate flame retardants, phosphate flame retardants, halogenated hydrocarbons and other halogen-containing flame retardants, melamine and its salts, reactive flame retardants, and inorganic flame retardants; preferably, the flame retardant is selected from a liquid flame retardant having a viscosity of 40 to 800 mPa.s at 25°C; more preferably, the flame retardant is a liquid flame retardant having a viscosity of 60 to 400 mPa.s at 25°C; More preferably, the flame retardant consists of flame retardant 1 and flame retardant 2; the flame retardant 1 is a reactive flame retardant, and the flame retardant 1 is preferably selected from at least one of tris(dipropylene glycol)phosphite, N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, N,N-bis(2-hydroxyethyl)aminomethylphosphonic acid dimethyl ester, and FR212 of Wanhua Chemical; the flame retardant 2 is one or two of a halogenated phosphate flame retardant and a phosphate flame retardant, and the flame retardant 2 is preferably selected from at least one of tris(2-chloroethyl)phosphate, (2-chloropropyl)phosphate, di(3-bromo-2,2-dimethylpropyl)phosphate, dimethyl methyl phosphate, diethyl ethyl phosphate, dimethyl propyl phosphate, triethyl phosphate, triphenyl phosphate, and tricresyl phosphate.

7. The highly fatigue-resistant polyurethane composition according to claim 1 or 2, characterized in that: The chain extender is selected from at least one of diols, diamines, and diphenols, preferably selected from at least one of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol, cyclohexanediol, methylamine, ethylamine, hydrogenated bisphenol A, and hydroquinone; and / or The cross-linking agent is selected from at least one of polyols and polyamines, preferably selected from at least one of trimethylolpropane, glycerol, pentaerythritol, diethanolamine, triethanolamine, ethylenediamine, phenylenediamine and sorbitol; and / or The surfactant is at least one of polysiloxane-olefin oxide block copolymers; and / or The catalyst is selected from at least one of an amine catalyst and an organic metal catalyst.

8. The highly fatigue-resistant polyurethane composition according to any one of claims 1 to 7, characterized in that: The isocyanate reactive component also includes an auxiliary agent, which is preferably selected from at least one of a coupling agent, a filler, a smoke suppressant, a dye, an antistatic agent, an antioxidant, a light stabilizer, a diluent, a surface wetting agent, a leveling agent, a thixotropic agent, a viscosity reducer, and a plasticizer.

9. The highly fatigue-resistant polyurethane composition according to any one of claims 1 to 8, characterized in that: Based on the total mass of the isocyanate-reactive component, the isocyanate-reactive component comprises: Polyether polyol 1, 30-50%; Polyether polyol 2, 20-45%; Polymer polyols, 9-10%; Foaming agent, 0.8-1.3%; Flame retardant, 8-25%; Chain extender, 1-5%; Cross-linking agent, 1-3%; Surfactant, 0.3-0.8%; Catalyst, 0.5-1.2%; Pigment, 0.05-0.2%; Preferably, the molar ratio of isocyanate groups in the isocyanate component to active hydrogen atoms in the isocyanate reactive component in the polyurethane composition is 95-105:

100.

10. A method for preparing a polyurethane foaming and curing ballast bed using the highly fatigue-resistant polyurethane composition according to any one of claims 1 to 9, It is characterized in that The following steps are included: Step 1, at 10-60° C., respectively, the isocyanate component and the isocyanate reactive component are mixed and stirred evenly for later use; Step 2: at 10-60° C., the isocyanate component and the isocyanate reactive component are mixed evenly by equipment and then directly injected into the railway ballast or into a mold containing the ballast. After the reaction is completed, the polyurethane foaming molded and cured ballast bed is obtained directly or by opening the mold.

11. Use of the polyurethane foaming molded solidified ballast prepared by the method of claim 10 in railway tracks, especially for solidifying ballast in high-altitude and cold regions.

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