Microporous polyurethane elastomer compositions, flame retardant materials, preparation methods and applications

Abstract

This invention relates to a microporous polyurethane elastomer composition, a flame-retardant material, its preparation method, and its applications. The microporous polyurethane elastomer composition comprises the following components in parts by weight: polyisocyanate: 10-35 parts; polyether polyol: 35-90 parts; expandable graphite: 1-40 parts; ammonium polyphosphate: 1-40 parts; flame-retardant microspheres: 1-25 parts; chain extender: 1-10 parts; catalyst: 0.5-2 parts; and foaming agent: 0.1-2 parts. Compared with existing technologies, this invention overcomes the shortcomings of directly adding phosphate esters to polyurethane systems. The flame-retardant microspheres used are micron-sized particles with a uniform particle size distribution. While not affecting the mechanical properties of the microporous polyurethane elastomer, it also solves the problems of phosphate ester volatility, poor compatibility, and reduced vibration damping performance, thus expanding its application scenarios.

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials technology, and in particular to a microporous polyurethane elastomer composition, flame retardant material, preparation method and application. Background Technology

[0002] Polyurethane elastomers, due to their structure containing both soft and hard chain segments, can be molecularly designed to impart excellent properties such as high strength, good toughness, wear resistance, and vibration damping. Microporous polyurethane elastomers, with pore sizes mostly between 0.1 and 10 μm, are materials whose performance falls between that of elastomers and foams. They combine the lightweight, impact resistance, energy absorption, and cushioning properties of foams with the high strength and wear resistance of elastomers, making them widely used in rail engineering, architectural decoration, and automotive parts as a high-performance vibration damping material. However, polyurethane itself has drawbacks such as poor flame retardancy, a low oxygen index, and the release of large amounts of toxic gases and fumes like HCN and CO during combustion, limiting its application in areas with specific flame retardancy requirements. In the rail transit sector, microporous polyurethane elastomers are required to have good elasticity, low permanent compression set, and a dynamic-to-static stiffness ratio ≤1.35. Furthermore, the EU standard EN45545-2 "Fire Testing for Railway Vehicles - Fire Requirements for Materials and Components" and my country's Ministry of Railways' TB / T3237-2010 "Technical Conditions for Flame Retardant Materials for Interior Materials of High-Speed ​​Trains," officially released in August 2010, also have strict requirements regarding flame retardancy and smoke density, such as D. s4 ≤200.

[0003] Currently, polyurethane flame retardants mainly include traditional inorganic flame retardants such as magnesium hydroxide, aluminum hydroxide, and expandable graphite. However, these generally suffer from problems such as requiring large amounts, low flame retardant efficacy, poor compatibility with polymers, easy precipitation, and significant reduction in material performance. Traditional flame retardant systems can no longer meet application requirements. Maintaining excellent vibration damping performance while achieving good flame retardant properties is a current technical challenge for the application of microporous polyurethane elastomers. Chinese Patent Publication No. CN 114230763 A discloses a method for preparing a microporous polyurethane elastomer for building vibration damping, the microporous polyurethane elastomer, and a vibration damping component. The microporous polyurethane elastomer prepared using trihydroxy polybutadiene, polyether polyol, diphenylmethane diisocyanate, polymeric polyisocyanate, and polytetrahydrofuran diol has a static stiffness of 0.03 N / mm. 3 The elongation at break is 160%, and the permanent compression set is 8%, indicating good performance. However, it has not been modified for flame retardancy. Chinese Patent Publication No. CN 113563563 A discloses a low-density fatigue-resistant microporous polyurethane elastic vibration damping pad and its preparation method. The pad directly uses untreated dimethyl methyl phosphate (DMMP), resulting in a fire rating of B2(E) for the product. The flame retardant effect is low, limiting its application scenarios. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art by providing a microporous polyurethane elastomer composition, flame retardant material, preparation method and application, which solves the defects of directly adding phosphate ester to the polyurethane system. The flame retardant microspheres used are micron-sized particles with uniform particle size distribution. While not affecting the mechanical properties of the microporous polyurethane elastomer, it also solves the problems of easy volatility, poor compatibility and reduced vibration damping performance of phosphate ester, thus expanding its application scenarios.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The first aspect of the present invention provides a microporous polyurethane elastomer composition comprising the following components in parts by weight:

[0007] Polyisocyanates: 10-35 parts;

[0008] Polyether polyols: 35-90 parts;

[0009] Expandable graphite: 1-40 parts;

[0010] Ammonium polyphosphate: 1-40 parts;

[0011] Flame-retardant microspheres: 1-25 parts;

[0012] Chain extender: 1-10 parts;

[0013] Catalyst: 0.5-2 parts;

[0014] Foaming agent: 0.1-2 parts.

[0015] Furthermore, the polyisocyanate is an aromatic polyisocyanate.

[0016] Further, the polyisocyanate is selected from one or more of 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), carbodiimide-modified 4,4'-diphenylmethane diisocyanate (L-MDI), and toluene diisocyanate (TDI).

[0017] Furthermore, the polyether polyol with a molecular weight of 500-5000 includes one or more of the following: polypropylene glycol (PPG), polytetrahydrofuran glycol (PTHF), polyoxytetramethylene glycol (PTMEG), polypropylene oxide triol, propylene oxide-ethylene oxide coether triol, and tetrahydrofuran-propylene oxide coether diol.

[0018] Furthermore, the ammonium polyphosphate is type II ammonium polyphosphate (CAS No.: 68333-79-9);

[0019] The catalyst is selected from one or two of the following: triethylenediamine, pentamethyldiethylenetriamine, dibutyltin dilaurate, stannous octanoate, dibutyltin diacetate, and zinc isooctanoate;

[0020] The foaming agent is water.

[0021] Furthermore, the flame-retardant microspheres include a flame-retardant microsphere shell material and a flame-retardant microsphere core material;

[0022] The flame-retardant microspheres are prepared by suspension polymerization. Based on the interfacial characteristics of the oil phase and the water phase and the compatibility of phosphate ester with the oil phase, phosphate ester is used as the flame-retardant core material to make flame-retardant microspheres with a core-shell structure and then added to the microporous polyurethane elastomer. Through this structural design, the phosphate ester is wrapped in the shell to avoid direct contact between the phosphate ester and the polyurethane system. At the same time, the shell provides certain support for the polyurethane elastomer.

[0023] The comonomer of the flame-retardant microsphere shell material is selected from one or more of acrylonitrile (AN), vinylidene chloride (VDC), methyl methacrylate (MMA), methacrylic acid (MAA), methyl acrylate (MA), and N,N-dimethylacrylamide (DMAA).

[0024] The flame-retardant microsphere core material is selected from one or more of bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol bis(diphenyl phosphate) (RDP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloropropyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), triethyl phosphate (TEP), and triphenyl phosphate (TPP).

[0025] Further, the chain extender is selected from one or two of 1,4-butanediol, ethylene glycol, diethylene glycol, trimethylolpropane, trimethylolethane, triethanolamine, 3,3'-dichloro-4,4'-diphenylmethanediamine, 3,5-dimethylthiotoluenediamine, 3,5-diethyltoluenediamine, 4,4'-methylenebis(2,6-diethyl)aniline, 4,4'-methylenebis(2,6-diisopropyl)aniline, 4,4'-methylenebis(2-isopropyl-6-methyl)aniline, 2,4-diamino-3,5-dimethylthiochlorobenzene, 4,4'-bis-sec-butylaminodiphenylmethane, 1,4-bis-sec-butylaminobenzene, and 4,4'-diaminodiphenylmethane.

[0026] A second aspect of this invention provides a method for preparing a microporous polyurethane elastomer flame-retardant material, comprising the following steps:

[0027] S1: Weigh the above microporous polyurethane elastomer composition according to the proportion, add the mixed polyether polyol to the reactor, dehydrate it, add the polyisocyanate to the reactor, mix and stir, and keep the temperature at 85±5℃ for 0.5-2h to obtain the prepolymer, and store it in a sealed container.

[0028] S2: Mix the weighed chain extender, catalyst, and foaming agent evenly in proportion to obtain a mixed additive, and mix ammonium polyphosphate, expandable graphite, and flame retardant microspheres evenly in proportion to obtain a mixed flame retardant;

[0029] S3: The prepolymer, mixing additives and mixed flame retardant are fully mixed and reacted to obtain a polyurethane elastomer flame retardant material containing flame retardant microspheres.

[0030] A third aspect of the present invention provides a microporous polyurethane elastomer flame retardant material prepared by the method described above.

[0031] The fourth aspect of this invention provides the application of the above-mentioned microporous polyurethane elastomer flame-retardant material in the preparation of flame-retardant vibration damping materials.

[0032] The core concept of this invention contains the following mechanism:

[0033] The purpose of this invention is to provide a microporous polyurethane elastomer composition containing flame-retardant microspheres. The composition introduces flame-retardant microspheres as a flame-retardant component. These microspheres are micron-sized particles with a core material of phosphate ester, which is not easily soluble in the aqueous phase, and a polymer material as the shell material. Phosphate ester is a commonly used flame retardant for polyurethane, exhibiting excellent flame-retardant properties and minimal impact on the mechanical properties of the material. However, most phosphate ester products are liquid, have small molecular weights, high volatility, and less than ideal compatibility with polymers. Furthermore, the addition of liquid flame retardants significantly reduces the viscosity of the system, increases the porosity between the internal molecular chains of the microporous polyurethane elastomer, weakens intermolecular hydrogen bonding, and increases the open-cell ratio with higher dosages, thus reducing material performance and limiting its application. By utilizing the microscopic granulation mechanism of suspension polymerization, and based on the interfacial characteristics of the oil and aqueous phases and the compatibility of phosphate ester with the oil phase, flame-retardant microspheres with a core-shell structure are formed using phosphate ester as the flame-retardant core material and then added to the microporous polyurethane elastomer. This structural design encapsulates the phosphate ester within a shell, preventing direct contact between the phosphate ester and the polyurethane system. Simultaneously, the shell provides support to the polyurethane elastomer, thus overcoming the shortcomings of previous methods that directly added phosphate ester to the polyurethane system. These flame-retardant microspheres are micron-sized particles with a uniform particle size distribution. While maintaining the mechanical properties of the microporous polyurethane elastomer, they also address the issues of phosphate ester volatility, poor compatibility, and reduced vibration damping performance, expanding their application scenarios.

[0034] The microporous polyurethane elastomer composition containing flame-retardant microspheres prepared by this invention not only meets the requirements of permanent elastic deformation ≤8% and dynamic stiffness ratio ≤1.3, but also enables the material to meet the requirements of vertical flammability rating (UL94) V-0, LOI ≥29%, and smoke density D. s4 ≤200. It can effectively solve the problems of insufficient flame retardancy and excessive smoke density of microporous polyurethane elastomers, endowing polyurethane elastomer compositions with high flame retardancy properties without weakening their vibration damping performance, thus solving the problem in the prior art that it is difficult to combine high flame retardancy and excellent vibration damping performance.

[0035] Compared with the prior art, the present invention has the following technical advantages:

[0036] I. The microporous polyurethane elastomer composition containing flame-retardant microspheres prepared by this invention has good static stiffness and compression set performance, while meeting UL94 V-0 rating, LOI≥29%, and smoke density D. s4 ≤200, without changing the original vibration damping performance of polyurethane while maintaining excellent flame retardant properties.

[0037] Second, this invention uses flame-retardant microsphere technology, which overcomes the problems of easy volatility, poor compatibility and reduced vibration damping performance of phosphate ester flame retardants, and has little impact on the general performance of materials, thus expanding the application scenarios of microporous polyurethane elastomers. Attached Figure Description

[0038] Figure 1 The image shows a physical picture of the microporous polyurethane elastomer composition containing flame-retardant microspheres prepared in Example 1.

[0039] Figure 2 This is a SEM image of the microporous polyurethane elastomer composition containing flame-retardant microspheres prepared in Example 1. Detailed Implementation

[0040] The present invention comprises a microporous polyurethane elastomer composition containing flame-retardant microspheres, the composition comprising the following components and their weight percentages:

[0041] Polyisocyanates: 10-35 parts;

[0042] Polyether polyols: 35-90 parts;

[0043] Expandable graphite: 1-40 parts;

[0044] Ammonium polyphosphate: 1-40 parts;

[0045] Flame-retardant microspheres: 1-25 parts;

[0046] Chain extender: 1-10 parts;

[0047] Catalyst: 0.5-2 parts;

[0048] Foaming agent: 0.1-2 parts.

[0049] In this invention, the polyisocyanate is an aromatic polyisocyanate; the preferred polyisocyanate is one or more of 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), carbodiimide-modified 4,4'-diphenylmethane diisocyanate (L-MDI), and toluene diisocyanate (TDI).

[0050] In this invention, the polyether polyol is one or more of the following: polypropylene glycol (PPG), polytetrahydrofuran glycol (PTHF), polyoxytetramethylene glycol (PTMEG), polypropylene oxide triol, propylene oxide-ethylene oxide coether triol, and tetrahydrofuran-propylene oxide coether diol, with a molecular weight of 500-5000.

[0051] In this invention, the ammonium polyphosphate is type II ammonium polyphosphate.

[0052] In this invention, the comonomer of the flame-retardant microsphere shell material is one or more of acrylonitrile (AN), vinylidene chloride (VDC), methyl methacrylate (MMA), methacrylic acid (MAA), methyl acrylate (MA), and N,N-dimethylacrylamide (DMAA).

[0053] In this invention, the flame-retardant microsphere core material is one or more of bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol bis(diphenyl phosphate) (RDP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloropropyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), triethyl phosphate (TEP), and triphenyl phosphate (TPP).

[0054] In this invention, the catalyst is one or two of the following: triethylenediamine, pentamethyldiethylenetriamine, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, and zinc isooctanoate.

[0055] In this invention, the chain extender is one or two of the following: 1,4-butanediol, ethylene glycol, diethylene glycol, trimethylolpropane, trimethylolethane, triethanolamine, 3,3'-dichloro-4,4'-diphenylmethanediamine, 3,5-dimethylthiotoluenediamine, 3,5-diethyltoluenediamine, 4,4'-methylenebis(2,6-diethyl)aniline, 4,4'-methylenebis(2,6-diisopropyl)aniline, 4,4'-methylenebis(2-isopropyl-6-methyl)aniline, 2,4-diamino-3,5-dimethylthiochlorobenzene, 4,4'-bis-sec-butylaminodiphenylmethane, 1,4-bis-sec-butylaminobenzene, and 4,4'-diaminodiphenylmethane.

[0056] In this invention, the foaming agent is water.

[0057] A microporous polyurethane elastomer composition containing flame-retardant microspheres is prepared by a prepolymer method. The prepolymer method process described in this invention is as follows:

[0058] (1) Weigh the mixed polyether polyols according to the proportion and add them into the reactor. After dehydration, add the measured polyisocyanate into the reactor, mix and stir, and keep the temperature at 85±5℃. React for 0.5-2 hours, take it out, and seal it for storage.

[0059] (2) Mix chain extenders, catalysts, foaming agents and other additives in proportion.

[0060] (3) Mix ammonium polyphosphate, expandable graphite, flame retardant microspheres and other flame retardants in proportion.

[0061] (4) The weighed prepolymer, mixing additives and mixed flame retardant are thoroughly mixed and reacted to prepare a polyurethane elastomer composition containing flame retardant microspheres.

[0062] The microporous polyurethane elastomer composition containing flame-retardant microspheres prepared by this invention can be applied to vibration damping materials with high flame-retardant requirements.

[0063] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Any preparation methods, materials, structures, or compositional ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0064] Example 1

[0065] Add 65 parts (all parts by weight in this embodiment, and the polyol parts here are the sum of the parts of the two polyisocyanates; their respective proportions are adjusted according to process requirements and will not be elaborated here; if other embodiments use two polyols, the same expression form as this embodiment is used) of a mixed polyol with a molecular weight of 1000, PTMGE, and PPG with a molecular weight of 2000 into the reactor. After dehydration, add 25 parts of L-MDI, mix and stir, and maintain the temperature at 85±5℃ for 1 hour. Remove and seal for storage as a prepolymer; add 2 parts of 3,3'-dichloro-4,4 '-Diphenylmethane diamine, 2 parts trimethylolpropane, 0.5 parts stannous octoate, 0.1 parts triethylenediamine, and 0.2 parts water were mixed evenly as mixing additives. 25 parts ammonium polyphosphate, 10 parts expandable graphite, and 10 parts flame-retardant microspheres with AN as the comonomer of the shell material and BDP as the core material were used as mixed flame retardants. After the prepolymer, mixing additives, and mixed flame retardants were thoroughly mixed, the mixture was injected into a prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mixture was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0066] Example 2

[0067] 55 parts of a mixed polyol of PTMGE with a molecular weight of 1000 and PPG with a molecular weight of 2000 were added to a reactor. After dehydration, 25 parts of TDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 2 hours. The mixture was then removed and sealed for storage as a prepolymer. 4 parts of 3,3'-dichloro-4,4'-diphenylmethanediamine, 0.5 parts of stannous octoate, and 0.1 parts of water were mixed evenly as additives. 25 parts of ammonium polyphosphate, 8 parts of expandable graphite, and 8 parts of flame-retardant microspheres with AN as the comonomer of the shell material and RDP as the core material were used as flame retardants. The prepolymer, additives, and flame retardant were thoroughly mixed and injected into a prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mixture was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0068] Example 3

[0069] 55 parts of a mixed polyol with a molecular weight of 2000, PTMGE and PTHF, were added to a reactor. After dehydration, 15 parts of 4,4'-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 0.5 h. The mixture was then removed and sealed for storage as a prepolymer. 1.5 parts of 3,5-dimethylthiotoluene diamine, 1.5 parts of 1,4-butanediol, 1 part of pentamethyldiethylenetriamine, 1 part of dibutyltin dilaurate, and 1... Water was used as a mixing additive and mixed evenly. 14 parts of ammonium polyphosphate, 14 parts of expandable graphite, and 8 parts of flame-retardant microspheres with VDC as the comonomer of the shell material and TCEP as the core material were used as a mixed flame retardant. After the prepolymer, mixing additive and mixed flame retardant were fully mixed, they were injected into the prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mold was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0070] Example 4

[0071] 70 parts of a mixture of PTMGE (molecular weight 1000) and propylene oxide-ethylene oxide co-ether triol (molecular weight 5000) were added to a reactor. After dehydration, 25 parts of 2,4'-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and sealed for storage as a prepolymer. 3 parts of triethanolamine, 2 parts of trimethylolpropane, 0.5 parts of dibutyltin diacetate, 0.5 parts of triethylenediamine, and 2 parts of water were used as a mixture... The additives were mixed evenly. 10 parts of ammonium polyphosphate, 20 parts of expandable graphite, and 15 parts of flame-retardant microspheres with MMA as the comonomer of the shell material and TCPP as the core material were used as the mixed flame retardant. The prepolymer, additives, and mixed flame retardant were thoroughly mixed and then injected into the prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mold was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0072] Example 5

[0073] 35 parts of tetrahydrofuran-propylene oxide copolyether diol with a molecular weight of 1000 and PPG mixed polyol with a molecular weight of 500 were added to a reactor. After dehydration, 35 parts of 2,2'-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1.5 h. The mixture was then removed and sealed for storage as a prepolymer. 1.5 parts of triethanolamine, 1.5 parts of trimethylolpropane, 0.5 parts of dibutyltin diacetate, and 0.1 parts of 4,4'-methylenebis(2,6-diethyl) Aniline and 0.2 parts water were mixed evenly as a mixing additive; 21 parts ammonium polyphosphate, 7 parts expandable graphite, and 8 parts flame-retardant microspheres with MAA as the comonomer of the shell material and TDCPP as the core material were used as a mixed flame retardant; the prepolymer, mixing additive and mixed flame retardant were thoroughly mixed and then injected into the prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mold was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0074] Example 6

[0075] Ninety parts of a mixed polyol with a molecular weight of 2500 (polypropylene glycol) and a molecular weight of 4000 (PPG) were added to a reactor. After dehydration, 10 parts of L-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 0.5 h. The mixture was then removed and sealed for storage as a prepolymer. Ethylene glycol, 2 parts of trimethylolpropane, 0.5 parts of zinc isooctanoate, 0.1 parts of triethylenediamine, and 0.2 parts of water were mixed evenly as a mixing agent. Thirty parts of ammonium polyphosphate, 10 parts of expandable graphite, and 10 parts of flame-retardant microspheres with MA as the comonomer of the shell material and TEP as the core material were used as a mixed flame retardant. The prepolymer, mixing agent, and mixed flame retardant were thoroughly mixed and injected into a prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1 MPa. After 3 h, the mixture was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0076] Example 7

[0077] A mixture of 65 parts of PTMGE (molecular weight 1000) and PPG (molecular weight 2000) polyols was added to a reactor. After dehydration, 25 parts of L-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and sealed for storage as a prepolymer. 2 parts of 4,4'-methylenebis(2-isopropyl-6-methyl)aniline, 2 parts of trimethylolpropane, 0.5 parts of stannous octoate, 0.1 parts of triethylenediamine, and 0.2 parts of... Water was used as a mixing additive and mixed evenly. 40 parts of ammonium polyphosphate, 1 part of expandable graphite, and 10 parts of flame-retardant microspheres with DMAA as the comonomer of the shell material and TPP as the core material were used as a mixed flame retardant. After the prepolymer, mixing additive and mixed flame retardant were fully mixed, they were injected into the prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mold was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0078] Example 8

[0079] A mixture of 65 parts of PTMGE (molecular weight 1000) and PPG (molecular weight 2000) polyols was added to a reactor. After dehydration, 25 parts of L-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and sealed for storage as a prepolymer. 2 parts of 2,4-diamino-3,5-dimethylthiochlorobenzene, 2 parts of trimethylolpropane, 0.5 parts of stannous octoate, 0.1 parts of triethylenediamine, and 0.2 parts of water were used as... The additives were mixed evenly. One part ammonium polyphosphate, 40 parts expandable graphite, and 10 parts flame-retardant microspheres with AN as the comonomer of the shell material and BDP / TCPP as the core material were used as the mixed flame retardant. The prepolymer, additives and mixed flame retardant were thoroughly mixed and then injected into the prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mold was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0080] Example 9

[0081] 65 parts of a mixed polyol of PTMGE with a molecular weight of 1000 and PPG with a molecular weight of 2000 were added to a reactor. After dehydration, 25 parts of L-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and sealed for storage as a prepolymer. 2 parts of 4,4'-bis-sec-butylaminodiphenylmethane, 2 parts of trimethylolpropane, 0.5 parts of stannous octoate, 0.1 parts of triethylenediamine, and 0.2 parts of water were mixed evenly as a mixing agent. 35 parts of ammonium polyphosphate, 15 parts of expandable graphite, and 1 part of flame-retardant microspheres with AN as the comonomer of the shell material and BDP / TCEP as the core material were used as a mixed flame retardant. The prepolymer, mixing agent, and mixed flame retardant were thoroughly mixed and injected into a prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mixture was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0082] Example 10

[0083] A mixture of 65 parts of PTMGE (molecular weight 1000) and PPG (molecular weight 2000) polyols was added to a reactor. After dehydration, 25 parts of L-MDI were added, and the mixture was stirred and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and stored as a prepolymer in a sealed container. A mixture of 2 parts of 1,4-bis(sec-butylaminobenzene), 2 parts of 4,4'-diaminodiphenylmethane, 0.5 parts of stannous octoate, 0.1 parts of triethylenediamine, and 0.2 parts of water was prepared as a prepolymer. The additives were mixed evenly. 18 parts of ammonium polyphosphate, 7 parts of expandable graphite, and 25 parts of flame-retardant microspheres with VDC / MMA / AN as the comonomer of the shell material and RDP as the core material were used as the mixed flame retardant. The prepolymer, mixed additives and mixed flame retardant were thoroughly mixed and then injected into the prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mold was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0084] Example 11

[0085] 65 parts of a mixed polyol of PTMGE with a molecular weight of 1000 and PPG with a molecular weight of 2000 were added to a reactor. After dehydration, 25 parts of L-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and sealed for storage as a prepolymer. 5 parts of diethylene glycol, 5 parts of trimethylolethane, 0.5 parts of dibutyltin diacetate, 0.1 parts of triethylenediamine, and 0.2 parts of water were mixed evenly as a mixing agent. 25 parts of ammonium polyphosphate, 10 parts of expandable graphite, and 10 parts of flame-retardant microspheres with AN / MMA as the comonomer of the shell material and RDP as the core material were used as a mixed flame retardant. The prepolymer, mixing agent, and mixed flame retardant were thoroughly mixed and injected into a prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mixture was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0086] Example 12

[0087] Add 65 parts of a mixed polyol of PTMGE (molecular weight 1000) and PPG (molecular weight 2000) to a reactor. After dehydration, add 25 parts of L-MDI, mix and stir, and maintain the temperature at 85±5℃ for 1 hour. Remove and store as a prepolymer in a sealed container. Add 0.5 parts of 3,5-diethyltoluenediamine, 0.5 parts of 4,4'-methylenebis(2,6-diisopropyl)aniline, 0.5 parts of stannous octoate, and 0.1 parts of pentamethyldiethylenetriamine. 0.2 parts of water were mixed evenly as a mixing additive; 25 parts of ammonium polyphosphate, 10 parts of expandable graphite, and 10 parts of flame-retardant microspheres with VDC / MMA as the comonomer of the shell material and RDP as the core material were used as a mixed flame retardant; the prepolymer, mixing additive and mixed flame retardant were thoroughly mixed and then injected into the prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mold was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0088] Comparative Example 1

[0089] 65 parts of a mixed polyol of PTMGE with a molecular weight of 1000 and PPG with a molecular weight of 2000 were added to a reactor. After dehydration, 25 parts of L-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and sealed for storage as a prepolymer. 2 parts of 3,3'-dichloro-4,4'-diphenylmethanediamine, 2 parts of trimethylolpropane, 0.5 parts of stannous octoate, and 0.2 parts of water were mixed evenly as a mixing agent. After the prepolymer and mixing agent were thoroughly mixed, the mixture was injected into a prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mixture was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0090] Comparative Example 2

[0091] 65 parts of a mixed polyol of PTMGE with a molecular weight of 1000 and PPG with a molecular weight of 2000 were added to a reactor. After dehydration, 25 parts of L-MDI were added, mixed and stirred, and the temperature was maintained at 85±5℃ for 1 hour. The mixture was then removed and sealed for storage as a prepolymer. 2 parts of 3,3'-dichloro-4,4'-diphenylmethanediamine, 2 parts of trimethylolpropane, 0.5 parts of stannous octoate, and 0.2 parts of water were mixed evenly as a mixing agent. 25 parts of ammonium polyphosphate and 10 parts of expandable graphite were used as a mixed flame retardant. After the prepolymer, mixing agent, and mixed flame retardant were thoroughly mixed, the mixture was injected into a prepared mold. The mold was maintained at a temperature of 85±5℃ and a pressure of 20±1MPa. After 3 hours, the mixture was demolded to obtain a microporous polyurethane elastomer composition containing flame-retardant microspheres. The performance test results are shown in Table 1.

[0092] Table 1 Performance testing of microporous polyurethane elastomer compositions

[0093]

[0094] Note: Limiting oxygen index was tested according to GB / T 2406.2-2009 standard, permanent elastic deformation was tested according to ISO 1856 standard, dynamic stiffness ratio was tested according to TB / T3395.1 standard, vertical flammability rating was tested according to UL94-2018 standard, and smoke density was tested according to GB / T8323.2-2008 standard.

[0095] Figure 1 The image shows the microporous polyurethane elastomer composition containing flame-retardant microspheres prepared in Example 1. Figure 2 The image shown is an SEM image of the microporous polyurethane elastomer composition containing flame-retardant microspheres prepared in Example 1. It can be seen that the prepared composition has a uniform pore size distribution.

[0096] In summary, the microporous polyurethane elastomer composition containing flame-retardant microspheres prepared by the present invention has high flame-retardant properties without weakening its vibration damping performance (see Examples 1-12). It overcomes the problems of easy volatility, poor compatibility, and reduced vibration damping performance of phosphate ester flame retardants, and solves the problem in the prior art that it is difficult to achieve a combination of high flame retardant rating and excellent vibration damping performance.

[0097] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A microcellular polyurethane elastomer composition characterized in that, The following components by weight parts are included: Polyisocyanate: 10-35 parts; Polyether polyol: 35-90 parts; Expandable graphite: 1-40 parts; Ammonium polyphosphate: 1-40 parts; Flame-retardant microspheres: 1-25 parts; Chain extender: 1-10 parts; Catalyst: 0.5-2 parts; Foaming agent: 0.1-2 parts; The flame-retardant microspheres include a flame-retardant microsphere shell material and a flame-retardant microsphere core material; The flame-retardant microspheres are prepared by suspension polymerization, wherein the phosphoric acid ester is added to the microcellular polyurethane elastomer after being made into a flame-retardant microsphere with a core-shell structure as a flame-retardant core material according to the interface characteristics of the oil phase and the water phase and the compatibility of the phosphoric acid ester and the oil phase, the phosphoric acid ester is wrapped in the shell layer to avoid direct contact between the phosphoric acid ester and the polyurethane system, and the shell layer provides certain support for the polyurethane elastomer; The flame-retardant microsphere shell material is selected from one or more of acrylonitrile, vinylidene chloride, methyl methacrylate, methacrylic acid, methyl acrylate, and N, N-dimethyl acrylamide; The flame-retardant microsphere core material is selected from one or more of bisphenol A-bis (diphenyl phosphate), m-phenylenediamine bis (diphenyl phosphate), tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate, tris (1, 3-dichloro-2-propyl) phosphate, triethyl phosphate, and triphenyl phosphate.

2. A microcellular polyurethane elastomeric composition as claimed in claim 1, wherein, The polyisocyanate is an aromatic polyisocyanate.

3. A microcellular polyurethane elastomeric composition as claimed in claim 2, wherein, The polyisocyanate is selected from one or more of 4, 4 '-diphenylmethane diisocyanate, 2, 4 '-diphenylmethane diisocyanate, 2, 2'-diphenylmethane diisocyanate, carbodiimide-modified 4, 4 '-diphenylmethane diisocyanate, and toluene diisocyanate.

4. A microcellular polyurethane elastomeric composition as claimed in claim 2, wherein, The polyether polyol is one or more of polypropylene glycol, polytetrahydrofuran diol, polypropylene oxide triol, propylene oxide-ethylene oxide copolyether triol, and tetrahydrofuran-oxidized propylene copolyether diol with a molecular weight of 500-5000.

5. A microcellular polyurethane elastomeric composition as claimed in claim 2, wherein, The ammonium polyphosphate is type II ammonium polyphosphate. The catalyst is selected from one or both of triethylenediamine, pentamethyldiethylenetriamine, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, and zinc isooctoate. The foaming agent is water.

6. A microcellular polyurethane elastomeric composition as claimed in claim 2, wherein, The chain extender is selected from one or both of 1, 4-butanediol, ethylene glycol, diethylene glycol, trimethylolpropane, trimethyloloethane, triethanolamine, 3, 3'-dichloro-4, 4'-diphenylmethane diamine, 3, 5-dimethylthio toluene diamine, 3, 5-diethyl toluene diamine, 4, 4'-methylene bis (2, 6-diethyl) aniline, 4, 4'-methylene bis (2, 6-diisopropyl) aniline, 4, 4'-methylene bis (2-isopropyl-6-methyl) aniline, 2, 4-diamino-3, 5-dimethylthio chlorobenzene, 4, 4'-bis-sec-butylaminodiphenylmethane, 1, 4-bis-sec-butylaminobenzene, and 4, 4'-diaminodiphenylmethane.

7. A process for the preparation of a microcellular polyurethane elastomer flame retardant material characterized in that, The following steps are included: S1: The microcellular polyurethane elastomer composition according to any one of claims 1 to 6 is weighed in proportion, the mixed polyether polyol therein is added to a reactor, after dehydration treatment, the polyisocyanate is added to the reactor, mixed and stirred, and kept at a temperature of 85±5 ℃, reacted for 0.5-2 h to obtain a prepolymer, which is stored in a sealed state; S2: The chain extender, catalyst and foaming agent weighed in proportion are mixed uniformly to obtain a mixed additive, and the ammonium polyphosphate, expandable graphite and flame-retardant microspheres are mixed uniformly in proportion to obtain a mixed flame retardant; S3: The prepolymer, mixed additive and mixed flame retardant are mixed and reacted to obtain a polyurethane elastomer flame-retardant material containing flame-retardant microspheres.

8. A microcellular polyurethane elastomer flame-retardant material prepared by the method according to claim 7.

9. Use of the microcellular polyurethane elastomer flame-retardant material according to claim 8 in the preparation of a flame-retardant vibration-damping material.

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