Temperature-resistant microporous filling material and preparation method thereof

Abstract

The invention 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 A and a component B according to a mass ratio of 100: (93-95), the component A comprises the following raw materials: polyester polyol 1, polyester polyol 2, hydroxyl fluorosilicone oil, a hardener, a compound catalyst, water, a microsphere foaming agent and hollow glass beads; the component B comprises polyester polyol 2, pure MDI and liquefied MDI; the polyester polyol 1 is prepared by reacting maleic anhydride, polyester polyol with the hydroxyl value of 65-75 mgKOH / g and ethylene glycol. By introducing the hollow glass beads and utilizing maleic anhydride groups in the polyester polyol to enhance the dispersity, the processing fluidity, the dimensional stability, the mechanical property and the heat-resistant temperature of the material are synergistically improved, and the performance requirement of high-temperature forming of a carbon fiber product is met.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane, and particularly relates to a heat-resistant microporous filling material and a preparation method thereof. Background Art

[0002] Carbon fiber is known as the "black gold" in the materials field. It is lighter than metallic aluminum but stronger than steel. It has the characteristics of high modulus, low density, good fatigue resistance, and is as soft as textile fiber, making it easy to process. Therefore, it is widely used in military industry, sporting goods, automotive industry, energy, medical equipment and other fields.

[0003] In the sporting goods sector, high-end bicycle frames, forks, and other components are often manufactured using carbon fiber. Because carbon fiber is soft and difficult to shape before curing, it requires a suitable filler material to form a skeleton. The molding process typically involves two steps: first, curing the carbon fiber at 180°C to form it; second, extracting the skeleton from the formed frame or fork. This requires the inner lining skeleton material to possess both a certain degree of hardness and temperature resistance to prevent bulging and deformation at 180°C; and also to possess good toughness and mold release properties to facilitate smooth extraction from the carbon fiber product.

[0004] In existing technology, glass microspheres are often introduced to improve the performance of filler materials. Chinese patent CN119859239A discloses a method for preparing a polyurethane composite insulation board. This method uses hollow glass microspheres to improve the heat resistance of the polyurethane composite insulation board. To enhance the compatibility of the hollow glass microspheres with polyurethane, the method involves grafting styrene onto the surface of the hollow glass microspheres. However, this modification reduces the surface smoothness of the hollow glass microspheres, significantly affecting their flow properties.

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

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a heat-resistant microporous filling material. By introducing hollow glass microspheres and utilizing the maleic anhydride groups in polyester polyols to enhance their dispersibility, the processing fluidity, dimensional stability, mechanical properties and heat resistance of the material are synergistically improved; at the same time, the use of delayed and heat-sensitive composite catalysts effectively suppresses high-temperature bulging; the demolding effect is significantly improved by adding hydroxyl fluorosilicone oil, and finally a heat-resistant microporous filling material with excellent comprehensive performance is obtained to meet the performance requirements of high-temperature molding of carbon fiber products.

[0007] Another object of the present invention is to provide a method for preparing a heat-resistant microporous filling material, which has a simple process and is easy to mass-produce.

[0008] The technical solutions adopted by the present invention are as follows: The heat-resistant microporous filling material is made of component A and component B in a mass ratio of 100: (93-95), wherein component A includes 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 includes the following raw materials in parts by weight: Polyester polyol 2: 30-40 parts; Pure MDI: 50~60 parts; Liquefied MDI: 10-12 parts; Phosphoric acid: The dosage is 10-20 ppm based on 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 having a hydroxyl value of 65-75 mgKOH / g, and ethylene glycol; wherein the polyester polyol having a hydroxyl value of 65-75 mgKOH / g is prepared by esterifying one or more of ethylene glycol, diethylene glycol, or trimethylolpropane with adipic acid and terephthalic acid, and is preferably PE-2316 produced by Shandong Yinuowei Polyurethane Co., Ltd.; The polyester polyol 2 is prepared by esterification reaction of one or more of ethylene glycol, diethylene glycol or trimethylolpropane with adipic acid; The compound catalyst is a mixture of a delayed catalyst and a heat-sensitive catalyst.

[0009] The polyester polyol 1 has a functionality of 2.0-2.1, a hydroxyl value of 55-65 mgKOH / g, an acid value of less than 1 mgKOH / g, and a moisture content of less than 0.05 wt.%. The preparation method thereof comprises the following steps: 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) were added to the reactor. The temperature was raised to 135-140°C to start water release. The condensation reflux temperature was controlled at 100-105°C, and the temperature was raised to 220-240°C to continue the reaction. The reaction was terminated when the hydroxyl value reached the theoretical value to obtain polyester polyol 1.

[0010] The polyester polyol 2 has a functionality of 2.1-2.2, a hydroxyl value of 53-59 mgKOH / g, an acid value ≤0.5 mgKOH / g, and a number average molecular weight of 1900-2100, and is preferably PE-2325 produced by Shandong Yinuowei Polyurethane Co., Ltd.

[0011] The hardener is one or more of ethylene glycol, 1,4-butanediol or 1,3-propylene glycol.

[0012] In the composite catalyst, the mass ratio of the delayed catalyst to the heat-sensitive catalyst is 1:(0.5-0.8), preferably Dabco1027 and SA102 produced by Evonik Specialty Chemicals (Shanghai) Co., Ltd.

[0013] The decomposition temperature of the microsphere foaming agent is 144-152°C.

[0014] The hollow glass microspheres are micron-sized hollow glass microspheres with smooth surfaces and an apparent density of 0.12-0.2 g / cm 3 The particle size is 2~130μm, the wall thickness is 1~2μm, it has low density, high strength, high temperature resistance, good fluidity and chemical stability, and is preferably HM30 produced by Zhengzhou Shenglait Hollow Microsphere New Materials Co., Ltd.

[0015] The pure MDI is preferably MDI-100 produced by Wanhua Chemical Group Co., Ltd.

[0016] The liquefied MDI is preferably MM103C produced by BASF (China) Co., Ltd.

[0017] The method for preparing the heat-resistant microporous filling material comprises the following steps: (1) Polyester polyol 1, polyester polyol 2, hydroxy fluorosilicone oil, hardener, composite catalyst, water, microsphere foaming agent and hollow glass microspheres are put into a reactor for reaction to obtain component A; (2) Add polyester polyol 2 and phosphoric acid to the reactor, mix well, then 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) Component A and component B are mixed evenly according to the mass ratio, injected into the mold, and opened and matured after 7 to 10 minutes to obtain a heat-resistant microporous filling material.

[0018] In the step (1), the reaction temperature is 50-60°C and the reaction time is 1-2 hours; In the step (2), the reaction temperature after adding pure MDI is 73-77°C; after adding liquefied MDI, the reaction is continued for 15-20 minutes.

[0019] In the step (3), component A and component B are mixed and heated to 40-45°C, and the mold temperature is 40-50°C.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The heat-resistant microporous filling material of the present invention, by adding hollow glass microspheres, produces a microsphere effect with a tiny spherical structure, which effectively reduces the viscosity of the system, gives the system excellent fluidity, and facilitates processing; at the same time, its isotropic properties avoid uneven shrinkage caused by orientation, and ensure the dimensional stability of the product; (2) The present invention significantly enhances the adsorption on the surface of hollow glass microspheres by introducing a strong polar maleic anhydride group into the polyester polyol structure, ensuring that it is evenly dispersed in the system, thereby improving the temperature resistance of the product; (3) The present invention adopts a catalyst system composed of a delayed catalyst and a heat-sensitive catalyst, which can effectively delay the foaming speed, significantly reduce the cavitation on the surface and inside of the product, and avoid the bulging phenomenon during the subsequent high-temperature curing of the carbon fiber product; (4) The hydroxy fluorosilicone oil added to the formula components of the present invention 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; (5) The present invention uses a microsphere foaming agent to replace part of the water as the foaming agent, which can reduce the rigid polyurea structure produced when water is used as the foaming agent. The microsphere foaming agent forms a uniform closed-cell structure, which can effectively disperse stress concentration and inhibit the generation of internal defects in the material, thereby ensuring the physical properties of the product; (6) The preparation method of the present invention does not require a vulcanization step, which simplifies the process flow, reduces energy consumption, and improves economic benefits. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the following examples, but they do not limit the implementation of the present invention.

[0022] Unless otherwise specified, the raw materials used in the examples and comparative examples are conventional commercially available raw materials, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0023] Some of the raw materials used in the examples and comparative examples are described as follows: 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.%. The preparation method thereof comprises the following steps: 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, and the temperature was raised to 137.5±2.5°C to start water discharge. The condensation reflux temperature was controlled at 102.5±2.5°C, and the temperature was raised to 230±10°C to continue the reaction. The reaction was terminated when the hydroxyl value reached 60 mgKOH / g to obtain polyester polyol 1.

[0024] The decomposition temperature of the microsphere foaming agent is 148±4°C.

[0025] Example 1 The heat-resistant microporous filling material is made of component A and component B in a mass ratio of 100:93, wherein component A includes the following raw materials in parts by mass: Polyester polyol 1: 80 parts; PE-2325: 20 parts; Hydroxyfluorosilicone oil: 7 parts; Ethylene glycol: 8 parts; Compound catalyst: 0.9 parts; Water: 0.3 parts; Microsphere foaming agent: 9 parts; HM30: 9 parts; Component B includes the following raw materials in parts by weight: PE-2325: 35 parts; MDI-100: 55 parts; MM103C: 11 copies; Phosphoric acid: The dosage is 10ppm based on the total mass of PE-2325, MDI-100 and MM103C; The composite catalyst is a mixture of Dabco1027 and SA102, with a mass ratio of 1:0.7.

[0026] The method for preparing the heat-resistant microporous filling material comprises the following steps: (1) Polyester polyol 1, PE-2325, hydroxy fluorosilicone oil, ethylene glycol, composite catalyst, water, microsphere foaming agent and HM30 were added to the reactor and reacted at 55±5℃ for 1.5h to obtain component A; (2) Add PE-2325 and phosphoric acid to the reactor, stir for 10 minutes, mix well, add MDI-100, heat to 75±2℃ and react for 2.5 hours, then add MM103C at no more than 50℃ and continue to react for 15 minutes to obtain component B; (3) Component A and component B are mixed evenly according to the mass ratio, heated to 42.5±2.5℃, and injected into a mold with a mold temperature of 45±5℃. After 8 minutes, the mold is opened and matured to obtain a heat-resistant microporous filling material.

[0027] Example 2 The heat-resistant microporous filling material is made of component A and component B in a mass ratio of 100:95, wherein component A includes the following raw materials in parts by mass: Polyester polyol 1: 90 parts; PE-2325: 10 parts; Hydroxyfluorosilicone oil: 8 parts; 1,4-Butanediol: 10 parts; Compound catalyst: 1 part; Water: 0.3 parts; Microsphere foaming agent: 10 parts; HM30: 8 servings; Component B includes the following raw materials in parts by weight: PE-2325: 40 parts; MDI-100: 60 parts; MM103C: 10 copies; Phosphoric acid: The dosage is 10ppm based on the total mass of PE-2325, MDI-100 and MM103C; The composite catalyst is a mixture of Dabco1027 and SA102, with a mass ratio of 1:0.5.

[0028] The preparation method of the heat-resistant microporous filling material has the same steps as Example 1.

[0029] Example 3 The heat-resistant microporous filling material is made of component A and component B in a mass ratio of 100:93, wherein component A includes the following raw materials in parts by mass: Polyester polyol 1: 85 parts; PE-2325: 15 parts; Hydroxyfluorosilicone oil: 8 parts; Ethylene glycol: 10 parts; Compound catalyst: 0.9 parts; Water: 0.25 parts; Microsphere foaming agent: 9 parts; HM30: 9 parts; Component B includes the following raw materials in parts by weight: PE-2325: 35 parts; MDI-100: 55 parts; MM103C: 11 copies; Phosphoric acid: The dosage is 10ppm based on the total mass of PE-2325, MDI-100 and MM103C; The composite catalyst is a mixture of Dabco1027 and SA102, with a mass ratio of 1:0.7.

[0030] The preparation method of the heat-resistant microporous filling material has the same steps as Example 1.

[0031] Example 4 The heat-resistant microporous filling material is made of component A and component B in a mass ratio of 100:93, wherein component A includes the following raw materials in parts by mass: Polyester polyol 1: 80 parts; PE-2325: 20 parts; Hydroxyfluorosilicone oil: 5 parts; Ethylene glycol: 7 parts; Compound catalyst: 0.8 parts; Water: 0.2 parts; Microsphere foaming agent: 8 parts; HM30: 8 servings; Component B includes the following raw materials in parts by weight: PE-2325: 30 parts; MDI-100: 50 parts; MM103C: 10 copies; Phosphoric acid: The dosage is 10ppm based on the total mass of PE-2325, MDI-100 and MM103C; The composite catalyst is a mixture of Dabco1027 and SA102, with a mass ratio of 1:0.8.

[0032] The preparation method of the heat-resistant microporous filling material has the same steps as Example 1.

[0033] Example 5 The heat-resistant microporous filling material is made of component A and component B in a mass ratio of 100:95, wherein component A includes the following raw materials in parts by mass: Polyester polyol 1: 85 parts; PE-2325: 15 parts; Hydroxyfluorosilicone oil: 7 parts; 1,4-Butanediol: 8 parts; Compound catalyst: 0.9 parts; Water: 0.3 parts; Microsphere foaming agent: 10 parts; HM30: 8 servings; Component B includes the following raw materials in parts by weight: PE-2325: 40 parts; MDI-100: 55 parts; MM103C: 12 copies; Phosphoric acid: The dosage is 10ppm based on the total mass of PE-2325, MDI-100 and MM103C; The composite catalyst is a mixture of Dabco1027 and SA102, with a mass ratio of 1:0.6.

[0034] The preparation method of the heat-resistant microporous filling material has the same steps as Example 1.

[0035] Comparative Example 1 The difference from Example 1 is that the hydroxy fluorosilicone oil in component A is replaced by polyester polyol 1 in the same amount by weight, and the rest is the same as Example 1.

[0036] Comparative Example 2 The difference from Example 2 is that the microsphere foaming agent in component A is replaced with 0.3 parts by mass of water to ensure that the product density is close. Other details are the same as in Example 2.

[0037] Comparative Example 3 The difference from Example 2 is that HM30 is not added to component A, and the rest is the same as Example 2.

[0038] Comparative Example 4 The difference from Example 3 is that the composite catalyst in component A is replaced with 1.2 parts by mass of A33 to ensure a similar product maturation effect. The rest is the same as Example 3.

[0039] Comparative Example 5 The difference from Example 1 is that the polyester polyol 1 in component A is replaced by the same mass portion of PE-2316, and the rest is the same as Example 1.

[0040] The filling materials prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were subjected to performance tests, and the test methods were as follows: Density: Tested in accordance with GB / T 6343-2009; Hardness: Tested in accordance with GB / T 5574-2008; Tensile strength: Tested in accordance with GB / T 6344-2008; Elongation at break: Tested in accordance with GB / T 6344-2008; Tear strength: Tested in accordance with GB / T 10808-2006; Cut a sample of 200mm×200mm×5mm in size and ensure that the surface is flat, free of bubbles and damage. Turn on the oven and set the temperature to 180°C. After the temperature stabilizes, place the sample on the sample rack in the oven and heat at 180°C for 2 hours. After the heating treatment is completed, remove the sample and allow it to cool naturally to room temperature. Observe and record whether the sample has any deformation or bulging. Test method for appearance after skeleton extraction: Wrap carbon fiber cloth around a cylindrical filling material (skeleton) with a diameter of 40 mm and a length of 800 mm, heat it at a constant temperature of 180°C for 2 hours, then cool it to room temperature. After extracting the skeleton, observe whether the skeleton is damaged or cracked.

[0041] The test results are shown in Table 1.

[0042] Table 1 Performance test results

[0043] It can be seen from the data in Table 1 that the A and B components of the filling materials prepared in Examples 1 to 5 have good processing fluidity, and the skeleton products prepared therefrom maintain good dimensional stability and excellent mechanical properties. After being heated at a constant temperature of 180°C for 2h, the skeleton structure does not deform or bulge, which meets the performance requirements of high-temperature molding of carbon fiber products.

[0044] Comparing Comparative Example 1 with Example 1 reveals that replacing the hydroxyfluorosilicone oil in Component A with polyester polyol 1 in Comparative Example 1 results in surface damage to the skeleton after demolding from the carbon fiber product. This demonstrates that the siloxane barrier film formed by the hydroxyfluorosilicone oil on the skeleton surface effectively reduces interfacial friction during demolding, preventing damage to the skeleton due to mechanical stress and providing significant protection.

[0045] Comparing Comparative Example 2 with Example 2 shows that when the microsphere foaming agent is replaced with water, while the resulting filler density is similar, mechanical properties such as tensile strength and tear strength decrease. This demonstrates that the microsphere foaming agent, by forming a uniform closed-cell structure, effectively disperses stress concentration, suppresses the generation of internal defects in the material, and thus maintains excellent physical properties.

[0046] Comparison of Comparative Example 3 with Example 2 shows that when hollow glass beads are not added to the formulation, the resulting filling 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.

[0047] Comparing Comparative Example 4 with Example 3, it can be seen that although the same aging effect can be achieved by using A33 instead of the composite catalyst, the high catalytic activity of A33 and the relatively fast foaming speed lead to the formation of a large number of dark bubbles and voids in the prepared filling material. After heat treatment at 180°C for 2h, these defects further expand and cause surface bulging.

[0048] Comparing Comparative Example 5 with Example 1 reveals that after replacing maleic anhydride-modified polyester polyol 1 with PE-2316, the resulting filler exhibits localized deformation after heat treatment at 180°C for 2 hours. This is due to a lack of adsorption between the unmodified polyester polyol and the hollow glass microspheres, resulting in uneven dispersion of the hollow glass microspheres within the system and a local decrease in heat resistance. The highly polar groups introduced by maleic anhydride in Example 1 enhance the interfacial anchoring of the hollow glass microspheres, ensuring their uniform dispersion and thus improving the overall high-temperature resistance and structural stability of the filler.

Claims

1. A heat-resistant microporous filling material, characterized in that: It is made of component A and component B in a mass ratio of 100: (93~95), wherein component A includes 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 includes the following raw materials in parts by weight: Polyester polyol 2: 30-40 parts; Pure MDI: 50~60 parts; Liquefied MDI: 10-12 parts; Phosphoric acid: The dosage is 10-20 ppm based on 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 having a hydroxyl value of 65-75 mgKOH / g, and ethylene glycol; wherein the polyester polyol having a hydroxyl value of 65-75 mgKOH / g is prepared by esterifying one or more of ethylene glycol, diethylene glycol, or trimethylolpropane with adipic acid and terephthalic acid; The polyester polyol 2 is prepared by esterification reaction of one or more of ethylene glycol, diethylene glycol or trimethylolpropane with adipic acid; The compound catalyst is a mixture of a delayed catalyst and a heat-sensitive 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. The preparation method thereof comprises the following steps: Add polyester polyol with a hydroxyl value of 65-75 mgKOH / g, maleic anhydride and ethylene glycol to the reactor, raise the temperature to 135-140°C to start water release, control the condensation reflux temperature to 100-105°C, raise the temperature to 220-240°C and 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: The functionality of the polyester polyol 2 is 2.1-2.2, and the hydroxyl value is 53-59 mgKOH / g.

4. The heat-resistant microporous filling material according to claim 1, characterized in that: The hardener is one or more of ethylene glycol, 1,4-butanediol or 1,3-propylene glycol.

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

6. The heat-resistant microporous filling material according to claim 1, characterized in that: The decomposition temperature of the microsphere foaming agent is 144-152°C.

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

8. A method for preparing the heat-resistant microporous filling material according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Polyester polyol 1, polyester polyol 2, hydroxy fluorosilicone oil, hardener, composite catalyst, water, microsphere foaming agent and hollow glass microspheres are put into a reactor for reaction to obtain component A; (2) Add polyester polyol 2 and phosphoric acid to the reactor, mix well, then 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) Component A and component B are mixed evenly according to the mass ratio, injected into the mold, and opened and matured after 7 to 10 minutes to obtain a heat-resistant microporous filling material.

9. The method for preparing a heat-resistant microporous filling material according to claim 8, characterized in that: In the step (1), the reaction temperature is 50-60°C and the reaction time is 1-2 hours; In the step (2), the reaction temperature after adding pure MDI is 73-77°C; after adding liquefied MDI, the reaction is continued for 15-20 minutes.

10. The method for preparing a heat-resistant microporous filling material according to claim 8, characterized in that: In the step (3), component A and component B are mixed and heated to 40-45°C, and the mold temperature is 40-50°C.

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