Preparation method and application of modified phenolic resin

Abstract

The invention discloses a preparation method and application of modified phenolic resin, and the preparation method comprises the following steps: carrying out hydroxymethylation on nylon 6 or nylon 66 and formaldehyde or paraformaldehyde to form hydroxymethylated nylon; the hydroxymethylated nylon formed in the step S1001 reacts with phenol, formaldehyde or paraformaldehyde for about 4-6 hours at the temperature of 60-90 DEG C in a preset proportion under the condition of a basic catalyst, then the temperature is reduced to 50-60 DEG C, after vacuum decompression is conducted for about preset duration, water molecules in the reaction are removed, and a hydroxymethylated nylon modified phenolic resin matrix is prepared; a hydroxymethylated nylon modified phenolic resin matrix is prepared from 0-8% by weight of a first curing agent, 0-8% by weight of a second curing agent, 0-5% by weight of a flexibilizer, 0-5% by weight of a friction-resistant modifier, 0-5% by weight of a curing agent, 0-5% by weight of a curing agent, 0-5% by weight of a flame retardant, 0-5% by weight of a flame retardant, 0-5% by weight of a flame retardant, 0-5% by weight of a flame retardant, 0-5% by weight of a flame retardant and 0-5% by weight of a flame retardant. And one or more of the following components in percentage by weight: 0-2% of a fiber impregnating agent, and blending into a final product.

Description

Technical Field

[0001] The present invention relates to the field of preparation and application of fiber-reinforced composite resins, and specifically to a preparation method and application of a modified phenolic resin. Background Art

[0002] Fiber reinforced composite materials are being used more and more widely in industry due to their excellent specific strength, specific stiffness, light weight, corrosion resistance, resistance to marine bioadhesion, and non-magnetic properties.

[0003] Traditional phenolic resins offer excellent adhesion, and cured phenolic resins exhibit high heat resistance, excellent dielectric properties, and high mechanical properties. However, due to their high degree of crosslinking and high segment rigidity, the major drawbacks of cured phenolic resins are brittleness, low toughness, and poor impact resistance. However, with increasing demands for material performance, conventional phenolic resins are no longer able to meet the requirements of many high-tech fields. Therefore, modified phenolic resins have become an important means of improving the adhesion, heat resistance, wear resistance, and toughness of phenolic resins.

[0004] Polyamide (PA), also known as nylon, was invented by DuPont over half a century ago. To this day, polyamide remains a widely used plastic, particularly in the field of engineering plastics, where it has experienced rapid development and holds a significant position among the five major engineering plastics. PA comes in a wide variety of varieties, with PA6 and PA66 dominating the market, accounting for over 80% of the total. Compared to other engineering plastics, PA boasts excellent overall properties, including high mechanical strength, toughness, wear resistance, and oil resistance, making it a strong and resilient plastic. However, compared to metals, nylon suffers from disadvantages such as lower strength, modulus, and heat distortion temperature, high water absorption, poor dimensional stability, a certain degree of brittleness, and difficulty withstanding heavy loads, which limits its application.

[0005] A search of the prior art revealed that Chinese patent publication number CN201110075217.5 discloses a long-chain nylon-modified phenolic resin and a preparation method thereof. The invention comprises mixing a long-chain nylon, phenol, and an acidic catalyst, heating to dissolve the long-chain nylon, adding a formaldehyde aqueous solution dropwise, controlling the reaction temperature at 94-102°C, purifying, and drying to obtain a thermoplastic nylon-modified phenolic resin.

[0006] Chinese patent CN103540128B discloses a wear-resistant carbon fiber-reinforced nylon 66 resin composition and its preparation method. These compositions primarily address the low impact strength of existing wear-resistant carbon fiber-reinforced nylon 66 resin compositions, while the addition of impact modifiers further reduces tensile strength. These compositions can be used in the industrial production of injection-molded parts such as gears, bearings, pulleys, and mechanical pump rotors.

[0007] Wu Suli et al. wrote an article in the journal "Polymer Materials Science and Engineering" on pages 86-89 of Volume 16, Issue 6, 2000, describing the N-hydroxymethylation modification method and properties of nylon 66. Nylon 66 dissolved in formic acid solution underwent hydroxymethylation reaction with trioxymethylene aqueous solution at a certain reaction temperature (60°C). The resulting hydroxymethyl nylon 66 had enhanced resilience and lowered melting point. The reaction product was easily cross-linked and difficult to control. Its application fields and practical value were not introduced. Summary of the Invention

[0008] The hydroxymethyl nylon modified phenolic resin fiber reinforced composite material of the present application is less brittle after being cured with the existing common phenolic resin, has high toughness and good impact resistance, and can be used for shaft sleeves and pressure-bearing wear-resistant parts.

[0009] In addition, the hydroxymethyl nylon modified phenolic resin fiber reinforced composite material prepared in this application not only maintains the excellent bonding performance, excellent heat resistance, and unique anti-ablation performance of phenolic resin, but also has the advantages of chemical resistance, corrosion resistance, good processability, etc. of nylon resin. At the same time, the mechanical properties, heat resistance and impact toughness have also been greatly improved, and dimensional stability has also been significantly improved. The obtained fiber-reinforced hydroxymethyl nylon modified phenolic resin composite material is mainly used to manufacture industrial bushings and pressure-bearing wear-resistant parts. Compared with the currently used steel metal bushings, gears and other functional components and equipment, similar equipment manufactured using fiber-reinforced hydroxymethyl nylon modified phenolic resin composite materials has a series of advantages such as light weight, heat resistance, corrosion resistance, self-lubrication, wear resistance and pressure resistance.

[0010] To achieve at least one of the above advantages, the present application provides a method for preparing a hydroxymethyl nylon-modified phenolic resin, comprising the following steps: S1001, hydroxymethylating nylon 6 or nylon 66 with formaldehyde or paraformaldehyde to form hydroxymethylated nylon; S1002, the hydroxymethylated nylon formed in step S1001 is reacted with phenol, formaldehyde or paraformaldehyde in a predetermined ratio under the condition of an alkaline catalyst at a temperature of 60° C. to 90° C. for about 4 to 6 hours, and then the temperature is lowered to 50 to 60° C. and the pressure is reduced under vacuum for about a predetermined time to remove water molecules in the reaction, thereby preparing a hydroxymethylated nylon modified phenolic resin matrix; S1003, a hydroxymethylated nylon modified phenolic resin matrix is ​​prepared into a liquid hydroxymethylated nylon modified phenolic resin according to a predetermined weight ratio of the first curing agent to the hydroxymethylated nylon modified phenolic resin matrix of 0-8%, a weight ratio of the second curing agent to the hydroxymethylated nylon modified phenolic resin matrix of 0-8%, and one or more of the following: a toughening agent of 0-5% by weight, a friction resistance modifier of 0-5% by weight, and a fiber sizing agent of 0-2% by weight.

[0011] Preferably, the step S1001 includes: S10011A: Dissolve 10-30g of nylon 6 or nylon 66 in 400g-450ml phenol solution at 50-70°C. Add 60-100g of 37% formaldehyde solution or paraformaldehyde solution dropwise while stirring. Control the temperature at 65°C ± 5°C. React for 2-4 hours to obtain a hydroxymethylated nylon phenol solution.

[0012] Preferably, in step S10011A, the concentration of the formaldehyde solution or paraformaldehyde solution is 37%.

[0013] Preferably, the step S1001 includes: S10011B, first dissolve 10-30g of nylon 6 or nylon 66 in 200g of formic acid solution at 50-70℃, then add 60-100g of formaldehyde solution or paraformaldehyde solution dropwise while stirring, control the temperature at 65℃±5℃, react for 2-4 hours, cool to room temperature, add ammonia water to adjust the pH to about 7, until a white precipitate is precipitated; then wash the white precipitate with acetone solution and dry to obtain hydroxymethylated nylon.

[0014] Preferably, it satisfies at least one of the following conditions: The weight of hydroxymethyl nylon is 1-10% of the weight of phenol; The alkaline catalyst is a NaOH or KOH solution, the weight of which is 0.5-3% of the weight of phenol; The molar ratio of formaldehyde to phenol in the formaldehyde or paraformaldehyde solution is 1.4 to 1.8; The nylon is one or both of nylon 6 and nylon 66, with a melt flow rate of about 10g / 10min and a moisture content of no more than 0.2%; The first curing agent is implemented as follows: the weight of urotropine is 0-8% of the hydroxymethyl nylon modified phenolic resin matrix; the second curing agent 2- is an oxazoline curing agent, preferably one of phenylenebisoxazoline and 1,3-phenylenebisoxazoline, and the weight is 0-8% of the hydroxymethyl nylon modified phenolic resin matrix.

[0015] Preferably, it satisfies at least one of the following conditions: The weight of the toughening agent - tung oil is 0-5% of the hydroxymethyl nylon modified phenolic resin matrix; The weight of the friction resistance modifier - linseed oil is 0-5% of the hydroxymethyl nylon modified phenolic resin matrix; The fiber sizing agent is one of KH550 and KH560, and its weight is 0-2% of the hydroxymethyl nylon modified phenolic resin matrix.

[0016] According to another aspect of the present application, the present application also provides a method for preparing a fiber-reinforced composite material, which includes the following: The liquid hydroxymethyl nylon modified phenolic resin prepared by any of the above-mentioned hydroxymethyl nylon modified phenolic resin preparation methods is subjected to vacuum infusion or RTM injection molding process and reinforced with glass fiber or carbon fiber to form a high-performance composite material product; Liquid hydroxymethyl nylon modified phenolic resin and reinforced glass fiber or carbon fiber are made into prepreg, which is then compression molded to produce high-performance composite products.

[0017] Preferably, the weight ratio of the liquid hydroxymethyl nylon modified phenolic resin to the reinforcing glass fiber or carbon fiber fabric is 35%-50%:65%-50%.

[0018] Preferably, the reinforcing fibers are glass fibers or carbon fiber fabrics, and the fabrics are in the form of chopped fibers, fiber mats or fiber cloths.

[0019] According to another aspect of the present application, the present application provides a use of a liquid hydroxymethyl nylon modified phenolic resin prepared based on the above-mentioned method for preparing a hydroxymethyl nylon modified phenolic resin, which is used for the production of shaft sleeves and pressure-bearing wear-resistant parts. DETAILED DESCRIPTION

[0020] The preferred embodiments described below are for illustrative purposes only, and those skilled in the art may readily conceive of other obvious variations. The basic principles of the present invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0021] Example 1

[0022] Step 1: Control the temperature of a constant-temperature water bath at approximately 65°C. Add 400g of phenol solution to a 2L reactor, then add 24g of nylon 66. Stir at approximately 150 rpm. After approximately 4 hours, the nylon 66 is completely dissolved in the phenol solution. Then, add 60g of 37% formaldehyde solution dropwise while stirring. Keep the temperature at 65°C and react for approximately 2 hours to obtain a hydroxymethylated nylon phenol solution.

[0023] Step 2: Slowly add 8g of 40% sodium hydroxide solution to the above 60°C solution, followed by 600g of formaldehyde solution, while stirring. Allow to react for 2 hours. Raise the temperature to 75°C and allow to react for another 2 hours. The solution will gradually thicken. Set the water bath temperature to 90°C and react for about half an hour. Then, cool the reactor to 60°C. Turn on the vacuum pump and evacuate the reaction flask for about 8 hours to remove most of the water until almost no bubbles form. This yields 500g of liquid hydroxymethyl nylon-modified phenolic resin. Slowly add 20g of tung oil and stir until the mixture is evenly mixed with the liquid resin. Slowly add 20g of linseed oil and stir until the liquid resin is evenly mixed. Slowly add 10g of KH550 silane coupling agent and stir until the liquid resin is evenly mixed. Drain the liquid hydroxymethyl nylon-modified phenolic resin and store it in a refrigerator at 4°C.

[0024] Step 3: Preheat the above solution resin to 50°C for about half an hour. Place 550g of liquid compounded hydroxymethyl nylon-modified phenolic resin into the resin mixing tank. Add 30g of hexamethylenetetramine and 30g of 1,3-phenylenedioxazoline to the mixing tank and stir evenly. Then, evenly apply the above resin to the reinforced fiber cloth 7781 and heat it in a 65°C oven for 15 minutes to form a prepreg. The prepreg is cut into a certain size as required, layered in a mold, and placed in a hot press for curing and molding. The curing pressure is 0.5MPa. The laminate is cured at 160°C for 120 minutes and then post-cured at 190°C for 180 minutes to produce the laminate.

[0025] Example 2

[0026] Step 1: First, add 24g of nylon 66 to a reactor, followed by 200g of 98% formic acid solution. Heat the water bath under the glass reactor to 60°C and stir at 150 rpm / min for approximately 3 hours until the nylon 66 is completely dissolved. Then, add 60g of 37% formaldehyde solution dropwise with stirring at 65°C. React for 2-4 hours. After cooling to room temperature, add ammonia water to adjust the pH to approximately 7 until a white precipitate forms. Wash the white precipitate with approximately 500g of acetone solution and dry for approximately 4 hours to obtain hydroxymethylated nylon.

[0027] Step 2: Heat a water bath to 60°C. Add 400g of phenol solution to the reactor and stir at 150 rpm / min for approximately 4 hours until the hydroxymethylated nylon is completely dissolved. Slowly add 8g of 40% sodium hydroxide solution to the 60°C solution, followed by 600g of formaldehyde solution, while stirring. Allow to react for 2 hours. Raise the temperature to 75°C and allow to react for another 2 hours. The solution will gradually thicken. Set the water bath temperature to 90°C and react for approximately half an hour. Cool the reactor to 60°C and start the vacuum pump. Evacuate the reaction flask for approximately 8 hours to remove most of the water until almost no bubbles form. Discharge the liquid hydroxymethylated nylon-modified phenolic resin matrix.

[0028] Step 3: Apply the above solution evenly to the reinforced fiber cloth 7781 and heat in a 65°C oven for 15 minutes to form a prepreg. Cut the prepreg into the required size, layer by layer in a mold, and place it in a hot press for curing at a pressure of 0.5 MPa. Curing at 160°C for 120 minutes and post-curing at 190°C for 180 minutes will produce a laminate.

[0029] Example 3

[0030] Step 1: Control the temperature of a constant-temperature water bath at approximately 65°C. Add 400g of phenol solution to a 2L reactor, then add 24g of nylon 66. Stir at approximately 150 rpm. After approximately 4 hours, the nylon 66 is completely dissolved in the phenol solution. Then, add 60g of 37% formaldehyde solution dropwise while stirring. Keep the temperature at 65°C and react for approximately 2 hours to obtain a hydroxymethylated nylon phenol solution.

[0031] Step 2: Slowly add 8g of 40% sodium hydroxide solution to the above 60°C solution, then dropwise add 600g of formaldehyde solution, stirring while adding dropwise, and react for 2 hours. Raise the temperature to 75°C and react for another 2 hours. The solution will gradually thicken. Set the water bath temperature to 90°C and react for about half an hour. Then cool the reactor to 60°C and start the vacuum pump. Vacuum the reaction flask for about 8 hours to remove most of the water until the reactor is almost free of bubbles. Discharge the liquid hydroxymethyl nylon-modified phenolic resin matrix and store it in a refrigerator at 4°C.

[0032] Step 3: Preheat the above solution resin to 50°C for approximately half an hour. Transfer 1000g of liquid hydroxymethyl nylon-modified phenolic resin matrix to the RTM injection molding machine and set the machine and molding mold temperature to 50°C. Cut the 7781 reinforced fiber cloth into a 300mm x 300mm mold size, lay eight layers of fiberglass cloth on the mold, and close the mold. Connect the RTM injection molding machine outlet to the mold inlet, inject the hydroxymethyl nylon-modified phenolic resin matrix into the mold, and maintain the mold temperature at 50°C for 1 hour. Adjust the mold temperature to 100°C. Once the temperature reaches 100°C, start the vacuum pump and continue to draw vacuum while pre-curing the composite panel. After 2 hours, adjust the mold temperature to 160°C and cure for 120 minutes. Then, post-cure at 190°C for 180 minutes to produce the laminate.

[0033] Example 4

[0034] Step 1: Control the temperature of a constant-temperature water bath at approximately 65°C. Add 400g of phenol solution to a 2L reactor, then add 24g of nylon 66. Stir at approximately 150 rpm. After approximately 4 hours, the nylon 66 is completely dissolved in the phenol solution. Then, add 60g of 37% formaldehyde solution dropwise while stirring. Keep the temperature at 65°C and react for approximately 2 hours to obtain a hydroxymethylated nylon phenol solution.

[0035] Step 2: Slowly add 8g of 40% sodium hydroxide solution to the above 60°C solution, followed by a dropwise addition of 600g of formaldehyde solution. Stir while adding dropwise and allow to react for 2 hours. Raise the temperature to 75°C and allow to react for another 2 hours. The solution will gradually thicken. Set the water bath temperature to 90°C and react for about half an hour. Then, cool the reactor to 60°C. Turn on the vacuum pump and evacuate the reaction flask for about 8 hours to remove most of the water until almost no bubbles form. This yields 500g of liquid hydroxymethyl nylon-modified phenolic resin. Slowly add 20g of tung oil and stir until the mixture is evenly mixed with the liquid resin. Slowly add 20g of linseed oil and stir until the liquid resin is evenly mixed. Slowly add 10g of KH550 silane coupling agent and stir until the liquid resin is evenly mixed. Drain the liquid hydroxymethyl nylon-modified phenolic resin and store in a refrigerator at 4°C.

[0036] Step 3: Preheat the above solution resin to 50°C for approximately half an hour. Transfer 550g of the liquid compounded hydroxymethyl nylon-modified phenolic resin to the RTM injection molding machine. Add 30g of hexamethylenetetramine and 30g of 1,3-phenylenedioxazoline to the injection molding machine's resin mixing tank and mix thoroughly with the 550g of liquid compounded resin. Prepare for injection molding. Set the injection molding machine and molding mold to 50°C. Cut reinforced fiber cloth 7781 into a mold size of 300mm x 300mm. Lay eight layers of fiberglass cloth on the mold and close the mold. Connect the RTM injection molding machine outlet to the mold inlet. Inject the hydroxymethyl nylon-modified phenolic resin matrix into the mold, maintaining the mold temperature at 50°C for 1 hour. Adjust the mold temperature to 100°C. Once the temperature is reached, start the vacuum pump and draw vacuum while the composite panel pre-cures. After 2 hours, the mold temperature was adjusted to 160°C, cured for 120 minutes, and then post-cured at 190°C for 180 minutes to produce a laminate.

[0037] Comparison example: Step 1: Control the temperature of a constant-temperature water bath at around 60°C. Add 400g of phenol solution to a 2L reactor and stir at approximately 150rpm / min. Then, dropwise add 660g of 37% formaldehyde solution while stirring. Keep the temperature at 60°C. Slowly add 8g of 40% sodium hydroxide solution, followed by 600g of formaldehyde solution while stirring. Let the reaction react for 2 hours. Raise the temperature to 75°C and let it react for another 2 hours. The solution will gradually thicken. Set the water bath temperature to 90°C. After reacting for about half an hour, cool the reactor to 60°C. Turn on the vacuum pump and evacuate the reactor for about 8 hours. Most of the water in the reaction flask is removed until there are almost no bubbles in the reactor. This results in liquid unmodified phenolic resin. Discard the solution and store it in a refrigerator at 4°C.

[0038] Step 2: Preheat the unmodified phenolic resin to 50°C for approximately half an hour. Apply the resin evenly to the reinforced fiber cloth 7781 and heat in a 65°C oven for 15 minutes to form a prepreg. Cut the prepreg to the required size, layer by layer in a mold, and place in a hot press for curing at a pressure of 0.5 MPa. Cure at 160°C for 120 minutes, followed by a post-cure at 190°C for 180 minutes to produce a laminate.

[0039] Performance testing methods The viscosity of all the above phenolic resins was tested using a Brookfield CAP2000 viscometer in accordance with the GB / T 2794-1995 method. The test results are shown in Appendix 1.

[0040] The flexural strength of the above laminates was tested using a Zwich 100KN testing machine in accordance with the GB / T 9341-2008 method. The test results are shown in Appendix 1.

[0041] The impact strength of the V-notch of the above-mentioned laminate was tested using an MTS 50KJ pendulum impact tester in accordance with the method of GB / T 1843.1-2008. The test results are shown in Appendix 1.

[0042]

[0043] It can be seen from the table that the flexural properties and impact strength of the phenolic resin fiber reinforced composites modified with hydroxymethyl nylon are improved.

[0044] Those skilled in the art will appreciate that the embodiments of the present invention described above are intended to be illustrative only and are not intended to limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and illustrated in the embodiments. Any variations or modifications may be made to the embodiments of the present invention without departing from the principles described.

Claims

1. A method for preparing a hydroxymethyl nylon modified phenolic resin, characterized in that: It includes the following steps: S1001, hydroxymethylating nylon 6 or nylon 66 with formaldehyde or paraformaldehyde to form hydroxymethylated nylon; S1002, the hydroxymethylated nylon formed in step S1001 is reacted with phenol, formaldehyde or paraformaldehyde in a predetermined ratio under the condition of an alkaline catalyst at a temperature of 60° C. to 90° C. for about 4 to 6 hours, and then the temperature is lowered to 50 to 60° C. and the pressure is reduced under vacuum for about a predetermined time to remove water molecules in the reaction, thereby preparing a hydroxymethylated nylon modified phenolic resin matrix; S1003, a hydroxymethylated nylon modified phenolic resin matrix is ​​prepared into a liquid hydroxymethylated nylon modified phenolic resin according to a predetermined weight ratio of the first curing agent to the hydroxymethylated nylon modified phenolic resin matrix of 0-8%, a weight ratio of the second curing agent to the hydroxymethylated nylon modified phenolic resin matrix of 0-8%, and one or more of the following: a toughening agent of 0-5% by weight, a friction resistance modifier of 0-5% by weight, and a fiber sizing agent of 0-2% by weight.

2. The method for preparing a hydroxymethyl nylon modified phenolic resin according to claim 1, wherein: The step S1001 includes: S10011A: Dissolve 10-30g of nylon 6 or nylon 66 in 400g-450ml phenol solution at 50-70°C. Add 60-100g of 37% formaldehyde solution or paraformaldehyde solution dropwise while stirring. Control the temperature at 65°C ± 5°C. React for 2-4 hours to obtain a hydroxymethylated nylon phenol solution.

3. The method for preparing a hydroxymethyl nylon modified phenolic resin according to claim 2, wherein: In step S10011A, the concentration of the formaldehyde solution or paraformaldehyde solution is 37%.

4. The method for preparing a hydroxymethyl nylon modified phenolic resin according to claim 1, wherein: The step S1001 includes: S10011B, first dissolve 10-30g of nylon 6 or nylon 66 in 200g of formic acid solution at 50-70℃, then add 60-100g of formaldehyde solution or paraformaldehyde solution dropwise while stirring, control the temperature at 65℃±5℃, react for 2-4 hours, cool to room temperature, add ammonia water to adjust the pH to about 7, until a white precipitate is precipitated; then wash the white precipitate with acetone solution and dry to obtain hydroxymethylated nylon.

5. The method for preparing a hydroxymethyl nylon modified phenolic resin according to claim 4, wherein: In step S10011B, the concentration of the formaldehyde solution or paraformaldehyde solution is 37%.

6. The method for preparing a hydroxymethyl nylon modified phenolic resin according to claim 1, wherein: It meets at least one of the following conditions: The weight of hydroxymethyl nylon is 1-10% of the weight of phenol; The alkaline catalyst is a NaOH or KOH solution, the weight of which is 0.5-3% of the weight of phenol; The molar ratio of formaldehyde to phenol in the formaldehyde or paraformaldehyde solution is 1.4 to 1.8; The nylon is one or both of nylon 6 and nylon 66, with a melt flow rate of about 10g / 10min and a moisture content of no more than 0.2%; The first curing agent is implemented as follows: the weight of urotropine is 0-8% of the hydroxymethyl nylon modified phenolic resin matrix; the second curing agent 2- is an oxazoline curing agent, preferably one of phenylenebisoxazoline and 1,3-phenylenebisoxazoline, and the weight is 0-8% of the hydroxymethyl nylon modified phenolic resin matrix.

7. The method for preparing a hydroxymethyl nylon modified phenolic resin according to claim 1, wherein: It meets at least one of the following conditions: The weight of the toughening agent - tung oil is 0-5% of the hydroxymethyl nylon modified phenolic resin matrix; The weight of the friction resistance modifier - linseed oil is 0-5% of the hydroxymethyl nylon modified phenolic resin matrix; The fiber sizing agent is one of KH550 and KH560, and its weight is 0-2% of the hydroxymethyl nylon modified phenolic resin matrix.

8. A method for preparing a fiber-reinforced composite material, characterized in that: These include the following: The liquid hydroxymethyl nylon modified phenolic resin prepared by the preparation method of any one of claims 1 to 7 is combined with reinforcing glass fiber or carbon fiber to form a high-performance composite material product through vacuum infusion or RTM injection molding process; Liquid hydroxymethyl nylon modified phenolic resin and reinforced glass fiber or carbon fiber are made into prepreg, which is then compression molded to produce high-performance composite products.

9. The preparation method according to claim 8, characterized in that It meets at least one of the following conditions: The weight ratio of the liquid hydroxymethyl nylon modified phenolic resin to the reinforced glass fiber or carbon fiber fabric is 35% to 50%: 65% to 50%; The reinforcing fibers are glass fibers or carbon fiber fabrics, and the fabrics are in the form of chopped fibers, fiber mats or fiber cloths.

10. Use of a liquid hydroxymethyl nylon modified phenolic resin prepared by the method for preparing a hydroxymethyl nylon modified phenolic resin according to any one of claims 1 to 8, characterized in that: It is used for the production of shaft sleeves and pressure-bearing wear-resistant parts.

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