Epoxy resin for carbon fiber bicycle prepreg and preparation method and application thereof

Abstract

The invention provides epoxy resin for a carbon fiber bicycle prepreg. The epoxy resin comprises resin, silicon powder, a curing agent, a flame retardant, a flexibilizer, imidazole and a coupling agent. According to the invention, glycidyl amine type epoxy resin meeting the quality standard is selected as basic resin, silicon powder is used as a filling material, modified anhydride is used as a curing agent, layered dihydroxy compounds (LDHs) are used as a flame retardant, and a proper flexibilizer and an imidazole compound catalyst are used as curing accelerators; and the silane coupling agent is used as a material for enhancing the binding force between the inorganic filler and the resin matrix. According to the carbon fiber bicycle component prepreg and the preparation method thereof, the single mechanical property is remarkably improved, more importantly, the comprehensive performance is comprehensively improved, the carbon fiber bicycle component prepreg can better adapt to various complex working conditions in practical application, and the strict requirements of high-end fields such as high-performance sports equipment and aerospace are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of epoxy resins and relates to an epoxy resin for carbon fiber bicycle prepregs, and in particular to an epoxy resin for comprehensively improving the mechanical properties of the carbon fiber prepregs. Silicon powder is added to the epoxy resin formula to significantly improve the mechanical properties of the composite material. The epoxy resin for carbon fiber bicycle prepregs, as well as a preparation method and application thereof. Background Art

[0002] Most carbon fiber prepregs currently used in the market use conventional epoxy resin as the matrix material. The basic components of the epoxy resin used in carbon fiber prepregs mainly include epoxy resin matrix (Epoxy Resin) and curing agent (Hardener), and sometimes accelerators, diluents, and other functional additives are added. Although it has certain mechanical properties, there is still much room for improvement in tensile strength, compressive strength, interlaminar shear strength, and in-plane shear strength.

[0003] Traditional epoxy resin formulas are difficult to meet the comprehensive material performance requirements of high-performance carbon fiber rims, especially when used in extreme environments.

[0004] To overcome the limitations of existing technologies, researchers have been exploring new epoxy resin formulations, hoping to achieve composite materials with even better performance by adjusting the ratios of the various components and adding specific functional additives. However, existing solutions often improve performance in one area at the expense of others, failing to achieve comprehensive optimization. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides an epoxy resin for carbon fiber bicycle prepreg, a preparation method, and an application thereof. The purpose is to comprehensively improve the mechanical properties of carbon fiber bicycle prepreg by optimizing the formula composition and introducing functional additives. The addition of silicon powder to the epoxy resin formula can significantly improve the mechanical properties of the composite material.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention provides an epoxy resin for carbon fiber bicycle prepreg. The epoxy resin comprises, by weight, 50-70 parts of resin, 20-30 parts of silicon powder, 10-30 parts of curing agent, 3-5 parts of flame retardant, 1-2 parts of toughening agent, 0.5-1.5 parts of imidazole and 0.5-0.8 parts of coupling agent.

[0008] As a preferred embodiment of the present invention, the resin is a glycidylamine epoxy resin with an epoxy value of 0.62.

[0009] As a preferred embodiment of the present invention, the curing agent is a modified acid anhydride with an acid value of 450-480; the flame retardant is an LDHs flame retardant; and the mesh size of the silicon powder is 800 mesh.

[0010] As a preferred embodiment of the present invention, the coupling agent is a silane coupling agent.

[0011] The present invention also provides a method for preparing the above-mentioned epoxy resin for carbon fiber bicycle prepreg, the preparation method comprising the following steps:

[0012] 1) Premixing: Mix the resin and silicon powder and mix them evenly using a gradient premixing process to obtain a premix;

[0013] 2) adding a curing agent to the premix obtained in step 1), mixing thoroughly, and then adding a flame retardant, a toughening agent, an imidazole, and a coupling agent in sequence, mixing uniformly, to obtain a mixture;

[0014] 3) mixing and degassing the mixture obtained in step 2);

[0015] 4) injecting the deaerated material from step 3) into a mold and performing a thermal curing treatment; gradually cooling the material to room temperature, crushing, screening, and drying the material to obtain an epoxy resin for carbon fiber bicycle prepreg.

[0016] As a preferred embodiment of the present invention, in step 1), the gradient premixing process is:

[0017] Speed: 500 rpm; Time: 10 min; Temperature: 23-27°C;

[0018] Speed: 1800 rpm; Time: 40 min; Temperature: 33-37°C;

[0019] Rotation speed: 200 rpm; time: 10 min; temperature 38-42°C.

[0020] As a preferred embodiment of the present invention, in step 3), the mixing temperature is 60-70° C., and the degassing time is 30 min.

[0021] As a preferred embodiment of the present invention, in step 4), the heat curing treatment is as follows: keeping at 80°C for 1 hour, keeping at 120°C for 2 hours, and keeping at 150°C for 1 hour, with a heating rate of 2°C / min.

[0022] As a preferred embodiment of the present invention, in step 4), the gradient cooling is as follows: cooling from 150°C to 120°C in 30 min; cooling from 120°C to 80°C in 20 min; and cooling from 80°C to room temperature.

[0023] Finally, the present invention provides an application of the above-mentioned epoxy resin in the field of preparing a carbon fiber bicycle; the carbon fiber bicycle includes a competition-level frame, an all-terrain handlebar set, a disc brake rim, and a children's frame; wherein, the competition-level frame is made by compounding epoxy resins with particle sizes of 200nm and 5μm, the all-terrain handlebar set is made by using epoxy resin with a particle size of 10-20μm, the disc brake rim is made by using epoxy resin with a particle size of 50μm, and the children's frame is made by using epoxy resin with a particle size of 100μm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The present invention achieves a comprehensive improvement in the mechanical properties of carbon fiber bicycle component prepregs through careful design and optimization of the epoxy resin formula.

[0026] 2) The addition of an appropriate amount of silicon powder not only improves the material's wear resistance and shock absorption properties, but also increases its compressive strength from 1231 MPa to 1500 MPa. This demonstrates that the improved material exhibits greater resistance to pressure, making it suitable for applications requiring high loads. The improved flexural strength also reduces deformation and damage when subjected to bending moments, maintaining structural integrity.

[0027] 3) The present invention not only achieves significant progress in single mechanical properties, but more importantly, achieves a comprehensive improvement in comprehensive performance, enabling carbon fiber bicycle component prepregs to better adapt to various complex working conditions in practical applications and meet the stringent requirements of high-end fields such as high-performance sports equipment and aerospace. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] The invention provides an epoxy resin for carbon fiber bicycle prepreg. The epoxy resin comprises, by weight, 50-70 parts of resin, 20-30 parts of silicon powder, 10-30 parts of curing agent, 3-5 parts of flame retardant, 1-2 parts of toughening agent, 0.5-1.5 parts of imidazole and 0.5-0.8 parts of coupling agent.

[0030] The present invention uses a glycidylamine-based epoxy resin that meets quality standards as the base resin, silica fume as the filler, a modified acid anhydride as the curing agent, layered dihydroxy compounds (LDHs) as the flame retardant, an appropriate toughening agent, an imidazole-based catalyst as the curing accelerator, and a silane coupling agent to enhance the bonding between the inorganic filler and the resin matrix. All raw materials undergo rigorous screening and pretreatment to remove impurities and ensure the purity of the final product.

[0031] In the present invention, the supplier of the glycidylamine epoxy resin is Huntsman, and the model / specification is MY721 (epoxy value 0.62).

[0032] The supplier of silicon powder is Lianrui New Materials, and the model / specification is 800 mesh spherical silicon micropowder.

[0033] The supplier of modified anhydride curing agent is Hunan Jiashengde, model / specification HN-5500 (acid value 480).

[0034] The supplier of flame retardant is Zhongke Runzi, model / specification: MgAl-LDHs (interlayer spacing 0.76nm).

[0035] The supplier of the toughening agent is Japan Soken Chemical, model / specification ST-2020 (core: nitrile rubber; shell: epoxy).

[0036] The supplier of imidazole is Evonik of Germany, model / specification EMI-24.

[0037] The supplier of the coupling agent is Dow Corning, model / specification KH-560 (γ-glycidyloxypropyltrimethoxysilane).

[0038] Example 1

[0039] This embodiment provides an epoxy resin for carbon fiber bicycle prepreg, which includes, by weight: 65 parts of glycidylamine epoxy resin, 25 parts of 800 mesh spherical silica powder, 10 parts of modified anhydride curing agent, 3 parts of MgAl-LDHs flame retardant, 1 part of toughening agent, 0.5 parts of imidazole and 0.5 parts of silane coupling agent.

[0040] Its preparation method is:

[0041] (1) Premixing: Glycidylamine epoxy resin and silica powder are mixed evenly in proportion, using high-speed stirring equipment to ensure full contact and uniform dispersion of the two materials. Micronized silica powder constructs a three-dimensional thermal conductivity network, ensuring uniform distribution of curing heat (temperature difference <5°C). Plasma treatment of the silica powder surface generates -Si-O- bonds, increasing the chemical bonding ratio with the epoxy.

[0042] A gradient premixing process was used: speed: 500 rpm, time: 10 minutes, temperature: 25 ± 2°C. Speed: 1800 rpm, time: 40 minutes, temperature: 35 ± 2°C. Speed: 200 rpm, time: 10 minutes, temperature: 40 ± 2°C. The gradient speed prevents particle agglomeration and achieves dispersion, homogenization, and stabilization in stages. The temperature was also matched to the resin viscosity curve.

[0043] (2) Curing agent addition: Add the modified anhydride curing agent to the premix and continue stirring until the curing agent is completely dissolved in the epoxy resin matrix. Nano-sized LDHs (50-100nm) delay the diffusion of pyrolysis gases through the intercalation effect; the core-shell toughening agent triggers silver streaks during crack propagation; EMI-24 and HN-5500 anhydride undergo a synergistic curing reaction; KH-560 silane coupling agent reduces the resin / carbon fiber contact angle from 75° to 60°. Rotation speed: 500 rpm; Time: 10 minutes; Temperature: 50±2°C

[0044] (3) Addition of functional additives: Flame retardant LDHs, toughening agent, catalyst, and coupling agent are then added. Each additive needs to be dried and crushed before addition to ensure uniform distribution in the system. Rotation speed: 1200 rpm; Time: 20 min; Temperature: 55 ± 2°C.

[0045] (4) Mixing and degassing: After all raw materials are fully mixed, vacuum degassing treatment is performed to eliminate bubbles that may be generated during the mixing process and ensure the density of the material.

[0046] Mixing temperature: 65±5℃ (precisely control the phase transition point), vacuum degree ≤1000pa, degassing time: 30min (ensure the bubble volume is <0.1%).

[0047] (5) Molding and curing: The degassed material is injected into the mold and placed in a curing oven for heat curing. After injection into the mold, a step-curing process is performed: 80°C / 1h → 120°C / 2h → 150°C / 1h, with a heating rate of 2°C / min. (Too fast a heating rate will cause the surface to harden and hinder the internal reaction).

[0048] (6) Cooling: Cool the cured resin to room temperature to prevent decomposition of the resin due to high temperature.

[0049] Gradient cooling: 150°C → 120°C (30 min) → 80°C (20 min) → room temperature (natural cooling), cooling rate control: <2°C / min.

[0050] (7) Crushing: Use crushing equipment to break the solidified resin into small particles for subsequent processing.

[0051] (8) Screening: Resin particles of different particle sizes are classified through screening equipment to meet different application requirements.

[0052] Competition-level frame: uses 200nm+5μm compound resin.

[0053] All-terrain handlebar set: using 10-20μm toughened resin.

[0054] Disc brake rim: Use 50μm high temperature resistant resin.

[0055] Children's bicycle frame: 100μm low-cost resin is selected

[0056] (9) Drying: Place the sieved resin pellets in a drying oven to remove moisture and other volatile substances, thereby improving the resin's stability and shelf life. Drying control: Temperature: 60 ± 5°C; Time: 5 hours; Moisture threshold: ≤ 0.5% (above this value will cause the prepreg's viscosity to decrease).

[0057] Comparative Example 1 is the same as Example 1, except that the flame retardant is changed from LDHs flame retardant to ATH flame retardant.

[0058] Comparative Example 2 is the same as Example 1, except that the toughening agent is changed to CTBN.

[0059] Comparative Example 3 is the same as Example 1, except that the mesh size of the silicon powder is changed to 400 mesh.

[0060] The epoxy resin prepared in Example 1 was mixed with the same batch of Fu Shenying SYT49S-12K carbon fiber prepreg to form a fiber with a surface density of 100g / m 2 , prepreg with a resin content of 37%. Corresponding specimens were prepared and tested according to the test standards. The test results are shown in Table 1.

[0061] Table 1. Test results

[0062]

[0063]

[0064] The epoxy resin prepared in Example 1 was compared with the resins obtained in Comparative Examples 1-3. The results are shown in Table 2.

[0065] Table 2. Resins of Example 1 and Comparative Examples 1-3

[0066]

[0067]

[0068] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention. Any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An epoxy resin for carbon fiber bicycle prepreg, characterized in that, The epoxy resin comprises, by weight, 50-70 parts of resin, 20-30 parts of silicon powder, 10-30 parts of curing agent, 3-5 parts of flame retardant, 1-2 parts of toughening agent, 0.5-1.5 parts of imidazole and 0.5-0.8 parts of coupling agent.

2. The epoxy resin for carbon fiber bicycle prepreg according to claim 1, characterized in that: The resin is a glycidylamine type epoxy resin with an epoxy value of 0.

62.

3. The epoxy resin for carbon fiber bicycle prepreg according to claim 1, characterized in that: The curing agent is a modified acid anhydride with an acid value of 450-480; the flame retardant is an LDHs flame retardant; and the mesh size of the silicon powder is 800 mesh.

4. The epoxy resin for carbon fiber bicycle prepreg according to claim 1, characterized in that: The coupling agent is a silane coupling agent.

5. A method for preparing an epoxy resin for carbon fiber bicycle prepreg according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: 1) Premixing: Mix the resin and silicon powder and mix them evenly using a gradient premixing process to obtain a premix; 2) adding a curing agent to the premix obtained in step 1), mixing thoroughly, and then adding a flame retardant, a toughening agent, an imidazole, and a coupling agent in sequence, mixing uniformly, to obtain a mixture; 3) mixing and degassing the mixture obtained in step 2); 4) injecting the deaerated material from step 3) into a mold and performing a thermal curing treatment; gradually cooling the material to room temperature, crushing, screening, and drying the material to obtain an epoxy resin for carbon fiber bicycle prepreg.

6. The method for preparing an epoxy resin for carbon fiber bicycle prepreg according to claim 5, characterized in that: In step 1), the gradient premixing process is: Speed: 500 rpm; Time: 10 min; Temperature: 23-27°C; Speed: 1800rpm; Time: 40 minutes; temperature 33-37°C; Rotation speed: 200 rpm; time: 10 min; temperature 38-42°C.

7. The method for preparing an epoxy resin for carbon fiber bicycle prepreg according to claim 5, characterized in that: In step 3), the mixing temperature is 60-70° C., and the degassing time is 30 min.

8. The method for preparing an epoxy resin for carbon fiber bicycle prepreg according to claim 5, characterized in that: In step 4), the heat curing treatment is as follows: keeping the temperature at 80° C. for 1 hour, keeping the temperature at 120° C. for 2 hours, and keeping the temperature at 150° C. for 1 hour, with a heating rate of 2° C. / min.

9. The method for preparing an epoxy resin for carbon fiber bicycle prepreg according to claim 5, characterized in that: In step 4), the gradient cooling is as follows: cooling from 150°C to 120°C in 30 min; cooling from 120°C to 80°C in 20 min; and cooling from 80°C to room temperature.

10. An application of epoxy resin for carbon fiber bicycle prepreg, characterized in that: The use of the epoxy resin described in any one of claims 1 to 4 or the epoxy resin prepared by the preparation method described in any one of claims 5 to 9 in the field of preparing carbon fiber bicycles; the carbon fiber bicycle includes a racing-grade frame, an all-terrain handlebar set, a disc brake rim, and a children's frame; wherein the racing-grade frame is made by compounding epoxy resins with particle sizes of 200nm and 5μm, the all-terrain handlebar set is made by using epoxy resin with a particle size of 10-20μm, the disc brake rim is made by using epoxy resin with a particle size of 50μm, and the children's frame is made by using epoxy resin with a particle size of 100μm.

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