Temperature resistant microcellular filler material and method of making same

Abstract

The present application belongs to the technical field of polyurethane, and particularly relates to a temperature-resistant microporous filling material and a preparation method thereof. The temperature-resistant microporous filling material is prepared from A component and B component at a mass ratio of 100: (93-95), wherein the A component comprises the following raw materials: polyester polyol 1, polyester polyol 2, hydroxyl fluorosilicone oil, hardening agent, compound catalyst, water, microsphere foaming agent and hollow glass microbead; the B component comprises polyester polyol 2, pure MDI and liquefied MDI; the polyester polyol 1 is prepared from maleic anhydride, polyester polyol with a hydroxyl value of 65-75 mgKOH / g and ethylene glycol. By introducing the hollow glass microbead and utilizing the maleic anhydride groups in the polyester polyol to enhance the dispersibility, the processing fluidity, the dimensional stability, the mechanical property and the heat resistance temperature of the material are synergistically improved, and the performance requirements of the high-temperature forming of the carbon fiber product are met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyurethane, and particularly relates to a temperature-resistant microporous filling material and a preparation method thereof. BACKGROUND

[0002] Carbon fiber is known as the "black gold" in the field of materials. It is lighter than aluminum and stronger than steel, has high modulus, low density, good fatigue resistance, and softness like textile fibers, and is easy to process, so it is widely used in military, sports goods, automobile industry, energy, medical devices and other fields.

[0003] In the field of sports goods, high-end bicycle frames, front forks and other parts are often made of carbon fiber. Since carbon fiber is soft before curing and cannot be shaped, a suitable filling material is needed as a skeleton. In the forming process, it is usually divided into two steps: first, the carbon fiber is cured at a high temperature of 180 DEG C; second, the skeleton is extracted from the formed frame and fork. This requires the skeleton material to have certain hardness and temperature resistance to prevent bulging and deformation at a high temperature of 180 DEG C, and to have good toughness and demolding effect to facilitate smooth extraction from the carbon fiber product.

[0004] In the prior art, glass microspheres are often introduced to improve the performance of the filling material. Chinese patent CN119859239A discloses a preparation method of a polyurethane composite insulation board, which improves the temperature resistance of the polyurethane composite insulation board by using hollow glass microspheres; to improve the compatibility of hollow glass microspheres and polyurethane, the method grafts styrene on the surface of the hollow glass microspheres for modification. However, the smoothness of the modified hollow glass microspheres will decrease, which will greatly affect their flow effect.

[0005] Therefore, there is an urgent need to develop a temperature-resistant microporous filling material with excellent high-temperature deformation resistance and good demolding property to meet the requirements of the lining filling material for the high-temperature curing forming process of carbon fiber products (such as frames and forks). SUMMARY

[0006] In view of the shortcomings of the prior art, the purpose of the present application is to provide a temperature-resistant microporous filling material, which introduces hollow glass microspheres and uses maleic anhydride groups in polyester polyols to enhance the dispersibility thereof, thereby synergistically improving the processing fluidity, dimensional stability, mechanical properties and heat resistance temperature of the material; at the same time, the use of a delayed and heat-sensitive compounded catalyst effectively inhibits high-temperature bulging; the addition of hydroxyl fluorosilicone oil significantly improves the demolding effect, and finally a temperature-resistant microporous filling material with excellent comprehensive performance is obtained, which meets the performance requirements of high-temperature forming of carbon fiber products.

[0007] Another object of the present application is to provide a preparation method of the temperature-resistant micro-porous filling material, which is simple in process and easy for large-scale production.

[0008] The technical scheme adopted in the present application is as follows:

[0009] The temperature-resistant micro-porous filling material is made of A component and B component in a mass ratio of 100: (93-95), wherein the A component comprises the following raw materials in mass fraction:

[0010] Polyester polyol 1: 80-90 parts;

[0011] Polyester polyol 2: 10-20 parts;

[0012] Hydroxyl fluorosilicone oil: 5-8 parts;

[0013] Hardening agent: 7-10 parts;

[0014] Compound catalyst: 0.8-1 part;

[0015] Water: 0.2-0.3 parts;

[0016] Microsphere foaming agent: 8-10 parts;

[0017] Hollow glass microbeads: 8-10 parts;

[0018] The B component comprises the following raw materials in mass fraction:

[0019] Polyester polyol 2: 30-40 parts;

[0020] Pure MDI: 50-60 parts;

[0021] Liquefied MDI: 10-12 parts;

[0022] Phosphoric acid: the amount is 10-20 ppm of the total mass of polyester polyol 2, pure MDI and liquefied MDI;

[0023] The polyester polyol 1 is prepared by reacting maleic anhydride, polyester polyol with a hydroxyl value of 65-75 mgKOH / g and ethylene glycol; wherein the polyester polyol with a hydroxyl value of 65-75 mgKOH / g is prepared by esterification reaction of one or more of ethylene glycol, diethylene glycol or trimethylolpropane with adipic acid and terephthalic acid, and is preferably PE-2316 produced by Shandong Yinaowei Polyurethane Co., Ltd.;

[0024] The polyester polyol 2 is prepared by esterification reaction of one or more of ethylene glycol, diethylene glycol or trimethylolpropane with adipic acid;

[0025] The compound catalyst is a mixture of a delayed catalyst and a heat-sensitive catalyst.

[0026] The polyester polyol 1 has a functionality of 2.0-2.1, a hydroxyl value of 55-65 mgKOH / g, an acid value of <1 mgKOH / g, and a moisture content of <0.05 wt.%; a preparation method thereof comprises the following steps:

[0027] The polyester polyol 1 is obtained by adding polyester polyol with a hydroxyl value of 65-75 mgKOH / g, maleic anhydride and ethylene glycol in a mass ratio of 48:(4-5):(3-4) into a reactor, heating to 135-140℃ to start water release, controlling the condensation reflux temperature to be 100-105℃, heating to 220-240℃ to continue the reaction, and terminating the reaction when the hydroxyl value reaches the theoretical value.

[0028] The polyester polyol 2 has a functionality of 2.1-2.2, a hydroxyl value of 53-59 mgKOH / g, an acid value of ≤0.5 mgKOH / g, and a number average molecular weight of 1900-2100, and is preferably PE-2325 produced by Shandong Yinaowei Polyurethane Co., Ltd.

[0029] The hardener is one or more of ethylene glycol, 1,4-butanediol or 1,3-propanediol.

[0030] In the complex catalyst, the mass ratio of the delay catalyst to the heat-sensitive catalyst is 1:(0.5-0.8), and preferably Dabco 1027 and SA102 produced by Wincat Special Chemical (Shanghai) Co., Ltd.

[0031] The decomposition temperature of the microsphere foaming agent is 144-152℃.

[0032] The hollow glass microbead is a micron-sized hollow glass microsphere with a smooth surface, an apparent density of 0.12-0.2 g / cm 3 , a particle size of 2-130 μm, and a wall thickness of 1-2 μm, and has the properties of low density, high strength, high temperature resistance, good fluidity and chemical stability, and is preferably HM30 produced by Zhengzhou Saintlight Hollow Microbead New Material Co., Ltd.

[0033] The pure MDI is preferably MDI-100 produced by Wanhua Chemical Group Co., Ltd.

[0034] The liquefied MDI is preferably MM103C produced by BASF (China) Co., Ltd.

[0035] The preparation method of the temperature-resistant microporous filling material comprises the following steps:

[0036] (1) The polyester polyol 1, the polyester polyol 2, the hydroxyl fluorosilicone oil, the hardener, the complex catalyst, the water, the microsphere foaming agent and the hollow glass microbead are put into a reactor to react to obtain the A component;

[0037] (2) adding polyester polyol 2 and phosphoric acid into the reactor, mixing uniformly, then adding pure MDI, after 2-3h reaction, adding liquefied MDI to continue the reaction until the reaction is completed, to obtain component B;

[0038] (3) mixing component A and component B uniformly according to the mass ratio, injecting into the mold, after 7-10min, opening the mold, curing, to obtain the temperature-resistant microcellular filling material.

[0039] In the step (1), the reaction temperature is 50-60℃, and the reaction time is 1-2h;

[0040] In the step (2), the reaction temperature after adding pure MDI is 73-77℃; after adding liquefied MDI, the reaction is continued for 15-20min.

[0041] In the step (3), after mixing component A and component B, heating to 40-45℃, the mold temperature is 40-50℃.

[0042] Compared with the prior art, the beneficial effects of the present application are as follows:

[0043] (1) The temperature-resistant microcellular filling material has the hollow glass microbeads added, the microspherical effect of the small spherical structure of the hollow glass microbeads effectively reduces the viscosity of the system, and the system has excellent fluidity, which is convenient for processing; meanwhile, the isotropic property avoids uneven shrinkage caused by orientation, and ensures the dimensional stability of the product;

[0044] (2) The strong polar maleic anhydride groups introduced in the polyester polyol structure significantly enhance the adsorption on the surface of the hollow glass microbeads, ensure the uniform dispersion of the hollow glass microbeads in the system, and thus improve the temperature resistance of the product;

[0045] (3) The catalyst system formed by the delayed catalyst and the heat-sensitive catalyst can effectively delay the foaming speed, significantly reduce the air voids on the surface and inside of the product, and avoid the occurrence of the drumming phenomenon during the subsequent high-temperature curing of the carbon fiber product;

[0046] (4) The hydroxyl fluorosilicone oil added in the formula component of the present application can form an extremely thin isolation film on the surface of the product, which can effectively reduce the friction coefficient between the filling material and the carbon fiber product, facilitate the smooth extraction of the filling material, and reduce the damage of the filling material;

[0047] (5) The use of microsphere foaming agent instead of part of water as foaming agent can reduce the rigid polyurea structure generated when water is used as foaming agent, and the uniform closed cell structure formed by the microsphere foaming agent can effectively disperse stress concentration and inhibit the generation of internal defects of the material, thereby ensuring the physical properties of the product;

[0048] (6) The preparation method of the present invention does not require a sulfidation step, which simplifies the process, reduces energy consumption, and improves economic benefits. Detailed Implementation

[0049] The present invention will be further described below with reference to the embodiments, but these embodiments do not limit the implementation of the present invention.

[0050] Unless otherwise specified, the raw materials used in the examples and comparative examples are all commercially available materials, and the process methods used in the examples and comparative examples are all conventional methods in the art.

[0051] The following is a description of some of the raw materials used in the examples and comparative examples:

[0052] The polyester polyol 1 has a functionality of 2, a hydroxyl value of 60 mgKOH / g, an acid value of 0.5 mgKOH / g, and a moisture content of 0.03 wt.%; its preparation method includes the following steps:

[0053] 100 parts by mass of maleic anhydride, 1200 parts by mass of PE-2316 and 75 parts by mass of ethylene glycol were added to the reactor. The temperature was raised to 137.5±2.5℃ to start effluent. The reflux temperature was controlled at 102.5±2.5℃. The temperature was raised to 230±10℃ to continue the reaction. The reaction was terminated when the hydroxyl value reached 60mgKOH / g to obtain polyester polyol 1.

[0054] The decomposition temperature of the microsphere foaming agent is 148±4℃.

[0055] Example 1

[0056] The aforementioned heat-resistant microporous filling material is made from component A and component B in a mass ratio of 100:93, wherein component A comprises the following raw materials in parts by mass:

[0057] Polyester polyol 1:80 parts;

[0058] PE-2325: 20 copies;

[0059] Hydroxyfluorosilicone oil: 7 parts;

[0060] Ethylene glycol: 8 parts;

[0061] Compound catalyst: 0.9 parts;

[0062] Water: 0.3 parts;

[0063] Microsphere foaming agent: 9 parts;

[0064] HM30: 9 servings;

[0065] Component B comprises the following parts by weight of raw materials:

[0066] PE-2325: 35 copies;

[0067] MDI-100: 55 servings;

[0068] MM103C: 11 servings;

[0069] Phosphoric acid: 10 ppm of the total mass of PE-2325, MDI-100 and MM103C;

[0070] The composite catalyst is a mixture of Dabco1027 and SA102 in a mass ratio of 1:0.7.

[0071] The preparation method of the heat-resistant microporous filling material includes the following steps:

[0072] (1) Polyester polyol 1, PE-2325, hydroxyl fluorosilicone oil, ethylene glycol, compound catalyst, water, microsphere foaming agent and HM30 were added to the reactor and reacted at 55±5℃ for 1.5h to obtain component A;

[0073] (2) Add PE-2325 and phosphoric acid to the reactor, stir for 10 min, mix evenly, add MDI-100, heat to 75±2 ℃ and react for 2.5 h, then add MM103C at no higher than 50 ℃ and continue to react for 15 min to obtain component B;

[0074] (3) Mix components A and B evenly according to the mass ratio, heat to 42.5±2.5℃, inject into a mold with a mold temperature of 45±5℃, open the mold and mature after 8 minutes to obtain a heat-resistant microporous filling material.

[0075] Example 2

[0076] The aforementioned heat-resistant microporous filling material is made from component A and component B in a mass ratio of 100:95, wherein component A comprises the following raw materials in parts by mass:

[0077] Polyester polyol 1:90 parts;

[0078] PE-2325: 10 copies;

[0079] Hydroxyfluorosilicone oil: 8 parts;

[0080] 1,4-Butanediol: 10 parts;

[0081] Compound catalyst: 1 part;

[0082] Water: 0.3 parts;

[0083] Microsphere foaming agent: 10 parts;

[0084] HM30: 8 servings;

[0085] Component B comprises the following parts by weight of raw materials:

[0086] PE-2325: 40 copies;

[0087] MDI-100: 60 servings;

[0088] MM103C: 10 servings;

[0089] Phosphoric acid: 10 ppm of the total mass of PE-2325, MDI-100 and MM103C;

[0090] The composite catalyst is a mixture of Dabco1027 and SA102 in a mass ratio of 1:0.5.

[0091] The preparation method of the heat-resistant microporous filling material is the same as that in Example 1.

[0092] Example 3

[0093] The aforementioned heat-resistant microporous filling material is made from component A and component B in a mass ratio of 100:93, wherein component A comprises the following raw materials in parts by mass:

[0094] Polyester polyol 1:85 parts;

[0095] PE-2325: 15 copies;

[0096] Hydroxyfluorosilicone oil: 8 parts;

[0097] Ethylene glycol: 10 parts;

[0098] Compound catalyst: 0.9 parts;

[0099] Water: 0.25 parts;

[0100] Microsphere foaming agent: 9 parts;

[0101] HM30: 9 servings;

[0102] Component B comprises the following parts by weight of raw materials:

[0103] PE-2325: 35 copies;

[0104] MDI-100: 55 servings;

[0105] MM103C: 11 servings;

[0106] Phosphoric acid: 10 ppm of the total mass of PE-2325, MDI-100 and MM103C;

[0107] The composite catalyst is a mixture of Dabco1027 and SA102 in a mass ratio of 1:0.7.

[0108] The preparation method of the heat-resistant microporous filling material is the same as that in Example 1.

[0109] Example 4

[0110] The aforementioned heat-resistant microporous filling material is made from component A and component B in a mass ratio of 100:93, wherein component A comprises the following raw materials in parts by mass:

[0111] Polyester polyol 1:80 parts;

[0112] PE-2325: 20 copies;

[0113] Hydroxyfluorosilicone oil: 5 parts;

[0114] Ethylene glycol: 7 parts;

[0115] Compound catalyst: 0.8 parts;

[0116] Water: 0.2 parts;

[0117] Microsphere foaming agent: 8 parts;

[0118] HM30: 8 servings;

[0119] Component B comprises the following parts by weight of raw materials:

[0120] PE-2325: 30 copies;

[0121] MDI-100: 50 servings;

[0122] MM103C: 10 servings;

[0123] Phosphoric acid: 10 ppm of the total mass of PE-2325, MDI-100 and MM103C;

[0124] The composite catalyst is a mixture of Dabco1027 and SA102 in a mass ratio of 1:0.8.

[0125] The preparation method of the heat-resistant microporous filling material is the same as that in Example 1.

[0126] Example 5

[0127] The aforementioned heat-resistant microporous filling material is made from component A and component B in a mass ratio of 100:95, wherein component A comprises the following raw materials in parts by mass:

[0128] Polyester polyol 1:85 parts;

[0129] PE-2325: 15 copies;

[0130] Hydroxyfluorosilicone oil: 7 parts;

[0131] 1,4-Butanediol: 8 parts;

[0132] Compound catalyst: 0.9 parts;

[0133] Water: 0.3 parts;

[0134] Microsphere foaming agent: 10 parts;

[0135] HM30: 8 servings;

[0136] Component B comprises the following parts by weight of raw materials:

[0137] PE-2325: 40 copies;

[0138] MDI-100: 55 servings;

[0139] MM103C: 12 servings;

[0140] Phosphoric acid: 10 ppm of the total mass of PE-2325, MDI-100 and MM103C;

[0141] The composite catalyst is a mixture of Dabco1027 and SA102 in a mass ratio of 1:0.6.

[0142] The preparation method of the heat-resistant microporous filling material is the same as that in Example 1.

[0143] Comparative Example 1

[0144] The difference from Example 1 is that the hydroxyl fluorosilicone oil in component A is replaced with the same mass of polyester polyol 1, otherwise it is the same as Example 1.

[0145] Comparative Example 2

[0146] The difference from Example 2 is that the microsphere foaming agent in component A is replaced with 0.3 parts by weight of water to ensure that the product density is similar. Otherwise, it is the same as Example 2.

[0147] Comparative Example 3

[0148] The difference from Example 2 is that HM30 is not added to component A, otherwise it is the same as Example 2.

[0149] Comparative Example 4

[0150] The difference from Example 3 is that the compound catalyst in component A is replaced with 1.2 parts by weight of A33 to ensure that the product maturation effect is similar. Otherwise, it is the same as Example 3.

[0151] Comparative Example 5

[0152] The difference from Example 1 is that polyester polyol 1 in component A is replaced with the same mass of PE-2316, otherwise it is the same as Example 1.

[0153] The filler materials prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests, and the test methods are as follows:

[0154] Density: Tested according to GB / T 6343-2009;

[0155] Hardness: Tested according to GB / T 5574-2008;

[0156] Tensile strength: Tested in accordance with GB / T 6344-2008;

[0157] Elongation at break: Tested according to GB / T 6344-2008;

[0158] Tear strength: Tested according to GB / T 10808-2006;

[0159] Cut a sample block with dimensions of 200mm×200mm×5mm, ensuring that the surface of the sample block is flat, free of bubbles, and undamaged. Turn on the oven and set the temperature to 180℃. After the temperature stabilizes, place the sample block on the sample rack inside the oven and heat at a constant temperature of 180℃ for 2 hours. After the heat treatment is completed, remove the sample block and allow it to cool naturally to room temperature. Observe and record whether the appearance of the sample shows any deformation or bulging.

[0160] Test method for appearance after skeleton removal: A cylindrical filling material (skeleton) with a diameter of 40mm and a length of 800mm is wrapped with carbon fiber cloth, heated at a constant temperature of 180℃ for 2 hours, and then cooled to room temperature. After the skeleton is removed, observe whether there is any damage or cracking.

[0161] The test results are shown in Table 1.

[0162] Table 1 Performance Test Results

[0163]

[0164] As can be seen from the data in Table 1, the A and B components of the filler materials prepared in Examples 1 to 5 have good processing fluidity. The skeleton products made from them maintain good dimensional stability and excellent mechanical properties. After being heated at 180°C for 2 hours, the skeleton structure does not deform or bulge, thus meeting the performance requirements of high-temperature molding of carbon fiber products.

[0165] A comparison of Comparative Example 1 and Example 1 shows that replacing the hydroxyl fluorosilicone oil in component A of Comparative Example 1 with polyester polyol 1 resulted in damage to the skeleton surface after demolding from the carbon fiber product. This indicates that the siloxane isolation film formed by the hydroxyl fluorosilicone oil on the skeleton surface can effectively reduce interfacial friction during demolding, prevent damage to the skeleton due to mechanical stress, and play a significant protective role.

[0166] A comparison of Comparative Example 2 and Example 2 shows that when the microsphere foaming agent is replaced with water, the tensile strength, tear strength, and other mechanical properties of the resulting filler materials decrease even when the density is similar. This indicates that the microsphere foaming agent, by forming a uniform closed-cell structure, can effectively disperse stress concentration and suppress the generation of internal defects in the material, thereby maintaining excellent physical properties.

[0167] Comparing Comparative Example 3 with Example 2, it can be seen that when hollow glass beads are not added to the formulation components, the resulting filler material exhibits significant deformation and dimensional shrinkage after heat treatment at 180°C for 2 hours, indicating that hollow glass microspheres play a key role in maintaining the high-temperature morphological stability of the product.

[0168] As can be seen from the comparison between Comparative Example 4 and Example 3, although the same aging effect can be achieved by using A33 to replace the compound catalyst, the high catalytic activity of A33 and the fast foaming speed result in a large number of dark bubbles and void defects inside the prepared filler material. After heat treatment at 180°C for 2 hours, the defects further expand and cause surface blistering.

[0169] Comparing Comparative Example 5 with Example 1, it can be seen that after replacing the maleic anhydride-modified polyester polyol 1 with PE-2316, the resulting filler material exhibited localized deformation after heat treatment at 180°C for 2 hours. This is because the unmodified polyester polyol lacks adsorption between itself and the hollow glass microspheres, resulting in uneven dispersion of the hollow glass microspheres in the system and a decrease in localized temperature resistance. In contrast, the strongly polar groups introduced by maleic anhydride in Example 1 enhanced the interfacial anchoring ability of the hollow glass microspheres, ensuring their uniform dispersion and thus improving the overall high-temperature resistance and structural stability of the filler material.

Claims

1. A heat-resistant microporous filling material, characterized in that, It is made from component A and component B in a mass ratio of 100:(93~95), wherein component A comprises the following raw materials in parts by mass: Polyester polyol 1: 80-90 parts; Polyester polyol 2: 10~20 parts; Hydroxyfluorosilicone oil: 5-8 parts; Hardener: 7-10 parts; Compound catalyst: 0.8~1 part; Water: 0.2~0.3 parts; Microsphere foaming agent: 8-10 parts; Hollow glass microspheres: 8-10 parts; Component B comprises the following parts by weight of raw materials: Polyester polyol 2: 30~40 parts; Pure MDI: 50-60 parts; Liquefied MDI: 10-12 parts; Phosphoric acid: The dosage is 10~20 ppm of the total mass of polyester polyol 2, pure MDI and liquefied MDI; The polyester polyol 1 is prepared by reacting maleic anhydride, a polyester polyol with a hydroxyl value of 65-75 mgKOH / g, and ethylene glycol; wherein the polyester polyol with a hydroxyl value of 65-75 mgKOH / g is prepared by esterification reaction of one or more of ethylene glycol, diethylene glycol, or trimethylolpropane with adipic acid and terephthalic acid. The polyester polyol 2 has a functionality of 2.1~2.2 and a hydroxyl value of 53~59 mgKOH / g, and is prepared by esterification reaction of one or more of ethylene glycol, diethylene glycol or trimethylolpropane with adipic acid. The hardener is one or more of ethylene glycol, 1,4-butanediol, or 1,3-propanediol; The composite catalyst is a mixture of a delayed catalyst and a thermosensitive catalyst.

2. The heat-resistant microporous filling material according to claim 1, characterized in that, The polyester polyol 1 has a functionality of 2.0~2.1 and a hydroxyl value of 55~65 mgKOH / g; its preparation method includes the following steps: Polyester polyol with a hydroxyl value of 65-75 mg KOH / g, maleic anhydride, and ethylene glycol are added to the reactor. The temperature is raised to 135-140℃ to start effluent. The reflux temperature is controlled at 100-105℃. The temperature is raised to 220-240℃ to continue the reaction. The reaction is terminated when the hydroxyl value reaches the theoretical value to obtain polyester polyol 1.

3. The heat-resistant microporous filling material according to claim 1, characterized in that, In the aforementioned composite catalyst, the mass ratio of the delayed catalyst to the thermosensitive catalyst is 1:(0.5~0.8).

4. The heat-resistant microporous filling material according to claim 1, characterized in that, The decomposition temperature of the microsphere foaming agent is 144~152℃.

5. The heat-resistant microporous filling material according to claim 1, characterized in that, The apparent density of the hollow glass microspheres is 0.12~0.2 g / cm³. 3 The particle size is 2~130μm and the wall thickness is 1~2μm.

6. A method for preparing a heat-resistant microporous filling material according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Polyester polyol 1, polyester polyol 2, hydroxyl fluorosilicone oil, curing agent, compound catalyst, water, microsphere foaming agent and hollow glass microspheres are added into the reactor to react and obtain component A; (2) Add polyester polyol 2 and phosphoric acid to the reactor, mix them evenly, add pure MDI, react for 2-3 hours, add liquefied MDI and continue the reaction until the reaction is complete to obtain component B; (3) Mix component A and component B evenly according to the mass ratio, inject into the mold, open the mold and mature after 7~10 minutes to obtain a heat-resistant microporous filling material.

7. The method for preparing the heat-resistant microporous filling material according to claim 6, characterized in that, In step (1), the reaction temperature is 50~60℃ and the time is 1~2h; In step (2), the reaction temperature after adding pure MDI is 73~77℃; after adding liquefied MDI, the reaction continues for 15~20min.

8. The method for preparing the heat-resistant microporous filling material according to claim 6, characterized in that, In step (3), after mixing components A and B, the mixture is heated to 40-45°C, and the mold temperature is 40-50°C.

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