A carbon fiber composite material for manufacturing special shoe tips and its preparation method

Abstract

This application relates to the technical field of safety toe cap preparation, in particular to a carbon fiber composite material for manufacturing special toe caps and a preparation method thereof. A carbon fiber composite material for manufacturing special toe caps is formed by hot pressing a number of carbon fiber prepregs; the carbon fiber prepregs are made from the following raw materials in parts by weight: 60 - 64 parts of carbon fiber, 25 - 28 parts of matrix resin, 3 - 4 parts of low shrinkage resin, 0.15 - 0.25 parts of initiator, 0.2 - 0.5 parts of crosslinking agent, 4 - 6 parts of styrene, 0.4 - 0.6 parts of magnesium oxide, 0.3 - 0.4 parts of defoaming agent, 1 - 1.5 parts of mold release agent, 0.6 - 0.8 parts of carbon nanotubes; the carbon fiber at least includes carbon fiber square cloth. The safety toe cap prepared by using the carbon fiber composite material in the present invention has good compressive strength, impact strength, and also has good antistatic performance, which can meet the electrostatic protection requirements of safety toe caps for the electronics industry.

Description

Technical Field

[0001] The present application relates to the technical field of safety toe cap preparation, and in particular to a carbon fiber composite material for manufacturing special toe caps and a preparation method thereof. Background Art

[0002] Safety shoes are foot protection tools with high mechanical strength, used to prevent operators from encountering sharp objects in the construction environment and heavy objects falling from high altitudes from hitting their toes, and are widely used in operating places such as metallurgy, mining, forestry, logistics transportation, quarrying, construction, petrochemical industry, electronics industry, food industry, textile industry, etc.

[0003] Safety toe caps are built into safety shoes to protect the wearer's toes from being hit by heavy objects. Existing traditional safety toe caps are steel safety toe caps, such as No. 25 steel safety toe caps, No. 40 steel safety toe caps, No. 45 steel safety toe caps, No. 50 steel safety toe caps, etc. Although the safety performance of steel safety toe caps is relatively high, their thickness ≥ 1.2 mm, and the mass of a single steel safety toe cap ≥ 90 g, resulting in relatively heavy safety shoes prepared with steel metal toe caps, which affects the mobility and flexibility of workers. In addition, the steel safety toe caps also have the problem of relatively poor anti-deformation performance. Once impacted by heavy objects falling from high altitudes, the steel safety toe caps cannot recover after being impacted. If new safety toe caps are not replaced in time, it will increase the risk of the toes being easily hit twice. The steel safety toe caps have the problem of relatively weak secondary protection performance after being hit.

[0004] To solve the problems of relatively heavy mass and relatively weak secondary protection performance of steel safety toe caps, non-metal toe caps made of fiberglass materials have been developed. The fiberglass mesh is impregnated with epoxy resin to form a fiberglass prepreg mesh sheet. The fiberglass prepreg mesh sheet is formed into a toe cap preform by the hand lay-up molding method, and the toe cap preform is hot-pressed and trimmed to obtain a fiberglass safety toe cap. The prepared fiberglass safety toe cap has the advantages of relatively light mass, good compressive strength, and relatively better anti-impact deformation performance compared with steel safety toe caps.

[0005] In the electronics industry, electrostatic protection requirements are extremely high in the production, maintenance and other links of electronic equipment. This requires that the safety toe cap also needs to have good antistatic performance. The existing fiberglass safety toe caps cannot meet the electrostatic protection requirements of the electronics industry. To solve the above problems, the inventor has developed a carbon fiber composite material with good conductivity for manufacturing special toe caps. Summary of the Invention

[0006] To solve the problem that the fiberglass safety toe cap cannot meet the electrostatic protection requirements of the electronics industry, the present invention provides a carbon fiber composite material for manufacturing special toe caps and a preparation method thereof. The toe cap prepared with the carbon fiber composite material can meet the electrostatic protection requirements of the electronics industry, and has excellent compressive strength and anti-impact strength.

[0007] A carbon fiber composite material for manufacturing special shoe tips provided by the present invention is achieved through the following technical solutions:

[0008] A carbon fiber composite material for manufacturing special shoe tips is formed by hot pressing several carbon fiber prepregs; the carbon fiber prepregs are made from the following raw materials in parts by weight: 60 - 64 parts of carbon fiber, 25 - 28 parts of matrix resin, 3 - 4 parts of low shrinkage resin, 0.15 - 0.25 parts of initiator, 0.2 - 0.5 parts of crosslinking agent, 4 - 6 parts of styrene, 0.4 - 0.6 parts of magnesium oxide, 0.3 - 0.4 parts of defoaming agent, 1 - 1.5 parts of mold release agent, 0.6 - 0.8 parts of carbon nanotubes; at least two double bonds are contained in the crosslinking agent; the matrix resin at least includes vinyl resin; the carbon fiber at least includes carbon fiber square cloth; the mold release agent is at least one of stearate, molybdenum disulfide, talcum powder, and fumed silica; the carbon nanotubes are at least one of hydroxyl - modified carbon nanotubes and amino - modified carbon nanotubes.

[0009] The present invention contains several carbon fiber square prepregs and hydroxyl - or amino - modified carbon nanotubes, effectively ensuring the compressive strength and impact strength of the prepared safety shoe tips, and forming a conductive network skeleton. Combining with the three - dimensional network conductive structure formed by short - cut carbon fibers + carbon nanotubes in the prepreg resin, it effectively improves the overall electrical conductivity and antistatic performance, and the safety shoe tips meet the electrostatic protection requirements of the electronics industry.

[0010] In the present invention, the carbon nanotubes are subjected to hydroxyl - or amino - modification treatment, which improves the compatibility between the carbon nanotubes and the matrix resin, enables the carbon nanotubes to be evenly dispersed inside the matrix resin, and forms a three - dimensional network conductive structure. This not only improves the overall compressive strength and impact strength, but also enhances the overall electrical conductivity and antistatic performance, effectively eliminating the harm of human static electricity and better meeting the electrostatic protection requirements of the electronics industry.

[0011] The special safety shoe tips made of carbon fiber composite materials are applicable to various places where static electricity accumulation needs to be prevented, especially suitable for industries such as the electronics industry, petrochemical industry, and medicine, eliminating potential safety hazards such as fires, explosions, or damage to electronic equipment that may be caused by static electricity.

[0012] The conductive shoes prepared from the special safety shoe tips made of carbon fiber composite materials can timely conduct the static electricity generated by the human body, avoiding problems such as breakdown and damage of electronic components caused by static electricity, and ensuring the quality of electronic products.

[0013] In flammable and explosive places such as chemical industry and petroleum, the conductive shoes prepared from the special safety shoe tips made of carbon fiber composite materials can effectively eliminate human static electricity, prevent the sparks generated by static electricity discharge from igniting the surrounding flammable and explosive substances, reduce the risk of safety accidents, and ensure the safety of staff and the place.

[0014] When working in dusty environments such as flour mills and coal mines, static electricity on the shoe body can easily absorb dust, which not only affects the production environment but may also cause dust explosions. Conductive shoes made of special safety toes made of carbon fiber composite materials can reduce static electricity on the human body, prevent dust from being absorbed by the toe surface, reduce work safety hazards, and ensure the safety of workers and venues.

[0015] In places with strict requirements on the electromagnetic environment, such as scientific research laboratories and data centers, static electricity on the shoe body will interfere with the normal operation of precision instruments. Conductive shoes made of special safety toes made of carbon fiber composite materials can help eliminate static electricity on the human body, reduce static electricity interference with the normal operation of precision instruments, and ensure the accuracy of experimental data and the stable operation of equipment.

[0016] Preferably, the carbon fiber is a carbon fiber woven cloth or the carbon fiber is a combination of a carbon fiber woven cloth and at least one of 0° carbon fiber and 90° carbon fiber.

[0017] When the carbon fiber is a carbon fiber lattice cloth, the carbon fiber prepreg is a carbon fiber lattice prepreg, and the carbon fiber composite material used to manufacture the special shoe head is formed by hot pressing a plurality of carbon fiber lattice prepregs;

[0018] When the carbon fiber is a carbon fiber lattice cloth and a 0° carbon fiber, the carbon fiber prepreg is a carbon fiber lattice prepreg and a 0° carbon fiber prepreg, and the carbon fiber composite material for manufacturing the special toe cap is formed by hot pressing a plurality of carbon fiber lattice prepregs and a plurality of 0° carbon fiber prepregs;

[0019] When the carbon fiber is carbon fiber lattice cloth and 90° carbon fiber, the carbon fiber prepreg is carbon fiber lattice prepreg and 90° carbon fiber prepreg, and the carbon fiber composite material for manufacturing the special toe cap is formed by hot pressing a plurality of carbon fiber lattice prepregs and a plurality of 90° carbon fiber prepregs;

[0020] When the carbon fiber is carbon fiber lattice cloth, 0° carbon fiber and 90° carbon fiber, the carbon fiber prepreg is carbon fiber lattice prepreg, 0° carbon fiber prepreg and 90° carbon fiber prepreg, and the carbon fiber composite material for manufacturing special shoe toes is formed by hot pressing a plurality of carbon fiber lattice prepregs, a plurality of 0° carbon fiber prepregs and a plurality of 90° carbon fiber prepregs;

[0021] The carbon fiber filaments in the 0° carbon fiber prepreg are evenly spaced along the 0° direction;

[0022] The carbon fiber filaments in the 90° carbon fiber prepreg are evenly spaced along the 90° direction.

[0023] Preferably, the carbon fiber lattice prepreg has a thickness of 0.2-0.8 mm.

[0024] Preferably, the weight per square meter of the carbon fiber square prepreg is 100 - 600 g / m 2 ; the specification of the carbon fiber in the carbon fiber square cloth is any one or a combination of 1K, 3K, 6K, 12K, and 24K.

[0025] Preferably, the specification of the carbon fiber filaments arranged at equal intervals along the 0° direction in the 0° carbon fiber prepreg is any one or a combination of 1K, 3K, 6K, 12K, and 24K.

[0026] More preferably, the specification of the carbon fiber filaments arranged at equal intervals along the 0° direction in the 0° carbon fiber prepreg is 12K.

[0027] Preferably, the specification of the carbon fiber filaments arranged at equal intervals along the 90° direction in the 90° carbon fiber prepreg is any one or a combination of 1K, 3K, 6K, 12K, and 24K.

[0028] More preferably, the specification of the carbon fiber filaments arranged at equal intervals along the 90° direction in the 90° carbon fiber prepreg is 12K.

[0029] By adopting the above technical solutions, the prepared carbon fiber safety toe caps all meet the protection standards of EN 22568, and the production process is relatively simple, which can reduce the production cost.

[0030] Preferably, the carbon fiber yarns in the 0° carbon fiber prepreg, 90° carbon fiber prepreg, and carbon fiber square prepreg are surface active functional group modified carbon fiber yarns. The preparation method of the surface active functional group modified carbon fiber yarns is as follows: first, untwist the carbon fiber yarns, then place the untwisted carbon fiber yarns in hydrogen peroxide for ultrasonic modification treatment for 10 - 20 minutes, and finally dry and twist them to obtain the surface active functional group modified carbon fiber yarns. The surface active functional group modified carbon fiber yarns contain active hydroxyl groups and active carboxyl groups.

[0031] By adopting the above technical solutions, the compatibility between the carbon fiber yarns and the matrix resin is improved, which can improve the overall compressive strength and impact strength of the safety toe caps. At the same time, it is also beneficial to improve the overall antistatic performance.

[0032] Preferably, the content of the carbon fiber square cloth in the carbon fiber square prepreg is 60 - 63 wt%, and the content of the carbon nanotubes is 0.70 - 0.75 wt%; the content of the carbon fiber filaments in the 0° carbon fiber prepreg and the 90° carbon fiber prepreg is 60 - 63 wt%, and the content of the carbon nanotubes is 0.70 - 0.75 wt%.

[0033] By adopting the above technical solution, 0° carbon fiber prepreg, 90° carbon fiber prepreg, and carbon fiber grid prepreg can be freely combined and stacked to form a prefabricated sheet with a thickness of 6 - 8.5 mm, and a carbon fiber safety toe cap meeting the protection standard of EN 22568 can be manufactured.

[0034] A preparation method of a carbon fiber composite material for manufacturing a special toe cap provided by the present invention is achieved through the following technical solutions:

[0035] A preparation method of a carbon fiber composite material for manufacturing a special toe cap includes the following steps:

[0036] Step 1, prepare carbon fiber prepreg;

[0037] Step 2, cure the carbon fiber prepreg in Step 1 at 40 - 50 °C for 36 - 48 h;

[0038] Step 3, cut the cured carbon fiber prepreg to obtain a finished carbon fiber prepreg that fits the shape of the molding die. The finished carbon fiber prepreg is stacked into a preformed toe cap by the manual lay-up method, and after hot pressing and molding, it is demolded and trimmed to obtain a finished carbon fiber safety toe cap.

[0039] The preparation method of the present invention is relatively simple, the production equipment used is relatively conventional, the production difficulty has relatively low professional requirements for operators, it is convenient to achieve batch manufacturing, and the production cost of the safety toe cap is reduced.

[0040] Preferably, the carbon fiber prepreg in Step 1 is a carbon fiber grid prepreg, and the preparation method of the carbon fiber grid prepreg is as follows: S1. Perform surface active functional group modification treatment on the carbon fiber grid cloth; at the same time, accurately measure and mix matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, release agent, and carbon nanotubes to obtain a mixture, and coat the mixture on the release paper for semi-curing treatment to obtain a plastic resin film; S2. Preheat and press two plastic resin films on the upper and lower surfaces of the carbon fiber grid cloth subjected to surface active functional group modification treatment respectively. The mass ratio of the total mass of the two plastic resin films to the mass of the carbon fiber grid cloth subjected to surface active functional group modification treatment is (60 - 64):(36 - 40), and the carbon fiber grid prepreg can be prepared.

[0041] Preferably, the carbon fiber prepreg in the first step is a carbon fiber square prepreg, and the preparation method of the carbon fiber square prepreg is as follows: S1. Perform surface active functional group modification on the carbon fiber square cloth; at the same time, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, release agent, and carbon nanotubes and mix them evenly to obtain a mixture; S2. Apply the mixture to the upper and lower surfaces of the carbon fiber square cloth with surface active functional group modification respectively, and dry and semi-cure it to obtain the carbon fiber square prepreg. The mass ratio of the carbon fiber square cloth with surface active functional group modification to the mixture in the carbon fiber square prepreg is (60-64):(36-40).

[0042] Preferably, the carbon fiber prepreg in the first step includes a 0° carbon fiber prepreg, and the preparation method of the 0° carbon fiber prepreg is as follows: S1. Perform surface active functional group modification on the carbon fiber filaments; at the same time, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, release agent, and carbon nanotubes and mix them evenly to obtain a mixture. Coating the mixture on the release paper and performing semi-curing treatment to obtain a plastic resin film; S2. Pass the carbon fiber filaments with surface active functional group modification through between two yarn guiding plates. The carbon fiber filaments between the yarn guiding plates are evenly spaced along the 0° direction. Preheat and press the plastic resin film on the upper and lower surfaces of the 0° carbon fiber filament layer with surface active functional group modification between the two yarn guiding plates respectively to obtain the 0° carbon fiber prepreg. The addition amount of the 0° carbon fiber filaments in the 0° carbon fiber prepreg is 60-64wt%.

[0043] Preferably, the carbon fiber prepreg in the first step includes a 90° carbon fiber prepreg, and the preparation method of the 90° carbon fiber prepreg is as follows:

[0044] S1. Perform surface active functional group modification on the carbon fiber filaments;

[0045] At the same time, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, release agent, and carbon nanotubes and mix them evenly to obtain a mixture. Coating the mixture on the release paper and performing semi-curing treatment to obtain a plastic resin film;

[0046] S2. Pass the carbon fiber filaments with surface active functional group modification through between two yarn guiding plates. The carbon fiber filaments between the yarn guiding plates are evenly spaced along the 90° direction. Preheat and press the plastic resin film on the upper and lower surfaces of the 9o° carbon fiber filament layer with surface active functional group modification between the two yarn guiding plates respectively to obtain the 90° carbon fiber prepreg. The addition amount of the 90° carbon fiber filaments in the 90° carbon fiber prepreg is 60-64wt%.

[0047] In summary, the present application has the following advantages:

[0048] 1. The safety toe cap made of the carbon fiber composite material in the present invention has good compressive strength and impact strength, and also has good electrical conductivity, which can meet the electrostatic protection requirements of the electronics industry.

[0049] 2. By controlling the total number of stacked carbon fiber prepregs, the wall thickness, compressive strength and impact strength of the carbon fiber safety toe cap can be adjusted, and the prepared carbon fiber safety toe caps all meet the protection standard of EN 22568.

[0050] 3. The thickness of the carbon fiber safety toe cap in the present invention can be customized according to customer needs. On the premise of meeting the protection standard of EN22568, a safety toe cap with a wall thickness of 6mm and a super-light series can be manufactured.

[0051] 4. The preparation method of the present invention is relatively simple, with low operation difficulty, and is convenient for industrial production and manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a physical display diagram of the glass fiber safety toe cap prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] In order to further understand the creativity and technological progress of the present invention, the preferred implementation schemes of the present invention will be described in detail below in combination with examples and comparative examples. It should be noted that: this specific embodiment is only an explanatory illustration of the technical solution of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law. EXAMPLE

[0054] A carbon fiber composite material for manufacturing special toe caps is formed by hot pressing a number of carbon fiber prepregs. By controlling the total number of hot pressing and compounding of carbon fiber prepregs, the wall thickness of the carbon fiber safety toe cap can be adjusted, and the compressive strength and impact strength of the carbon fiber safety toe cap can be adjusted. The carbon fiber safety toe caps all meet the protection standards of European standard EN22568, Canadian standard CSA and American standard ASTM.

[0055] The carbon fiber prepreg is made of the following raw materials in parts by weight: 60-64 parts of carbon fiber; 25-28 parts of matrix resin; 3-4 parts of low shrinkage resin; 0.15-0.25 parts of initiator; 0.2-0.5 parts of crosslinking agent; 4-6 parts of styrene; 0.4-0.6 parts of magnesium oxide; 0.3-0.4 parts of defoaming agent; 1-1.5 parts of release agent; 0.6-0.8 parts of carbon nanotubes.

[0056] The low shrinkage resin is specifically polycaprolactone NPG200.

[0057] The initiator is composed of a peroxide initiator and an organometallic catalyst. The peroxide initiator is at least one of benzoyl peroxide (BPO) and tert-butyl peroxy-2-ethylhexanoate (TBPO). The organometallic catalyst is at least one of tetraisopropyl titanate, dibutyltin dilaurate, and stannous octoate.

[0058] The mold release agent is at least one of stearate, molybdenum disulfide, talcum powder, and fumed silica.

[0059] The crosslinking agent in the carbon fiber prepreg formula contains at least two double bonds and can be at least one of dipropylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate.

[0060] The matrix resin in the carbon fiber prepreg formula includes at least vinyl resin, such as acrylate resin, modified acrylate, vinyl silicone resin, modified vinyl silicone resin, etc.

[0061] The carbon fiber in the carbon fiber prepreg formula includes at least carbon fiber square cloth.

[0062] Preferably, the carbon fiber in the carbon fiber prepreg formula is carbon fiber square cloth or is composed of carbon fiber square cloth combined with at least one of 0° carbon fiber filaments and 90° carbon fiber filaments.

[0063] The compatibility between the carbon fiber and the prepreg resin matrix in the carbon fiber prepreg formula is poor, and the carbon fiber needs to be surface-modified. Specifically, the carbon fiber yarns in 0° carbon fiber prepreg, 90° carbon fiber prepreg, and carbon fiber square prepreg are surface-active functional group modified carbon fiber yarns or electro-polymerization composite modified carbon fiber yarns.

[0064] The preparation method of the surface-active functional group modified carbon fiber yarn is as follows: first, untwist the carbon fiber yarn, then place the untwisted carbon fiber yarn in hydrogen peroxide for ultrasonic modification for 10 - 20 minutes, and finally dry and twist it to obtain the surface-active functional group modified carbon fiber yarn, which contains active hydroxyl groups and active carboxyl groups.

[0065] Method 1. The preparation method of the surface-active functional group modified carbon fiber yarn is as follows: First, untwist the carbon fiber yarn, and then place the untwisted carbon fiber yarn in hydrogen peroxide for ultrasonic modification for 10 - 20 minutes. The ultrasonic modification time is related to the selected carbon fiber yarn specifications. Specifically, for 1K carbon fiber yarn, the ultrasonic modification time is 10 - 12 minutes; for 3K carbon fiber yarn or 3K carbon fiber yarn, the ultrasonic modification time is 14 - 16 minutes; for 6K carbon fiber yarn or 6K carbon fiber yarn, the ultrasonic modification time is 16 - 18 minutes; for 12K carbon fiber yarn or 12K carbon fiber yarn, the ultrasonic modification time is 18 - 20 minutes. Finally, dry and twist it to obtain the surface-active functional group modified carbon fiber yarn. The surface-active functional group modified carbon fiber yarn contains active hydroxyl groups and active carboxyl groups.

[0066] Method 2. The preparation method of the electro-polymerization composite modified carbon fiber yarn is as follows: First, clean the surface of the carbon fiber yarn; then perform electro-polymerization in a three-electrode system, and polyaniline nanosheets are formed on the surface of the carbon fiber yarn by electro-polymerization. Specifically, the cleaned carbon fiber yarn is used as the working electrode, the platinum sheet is used as the counter electrode, and Ag / AgCl is used as the reference electrode. The electro-polymerization solution contains 0.1 - 0.2 M / L of aniline monomer and 0.025 - 0.05 / L of aniline monomer, the cyclic voltage is 0.7 - 1.4 V, and the electro-polymerization time is 5 - 15 minutes. [[ID=�]]

[0067] Due to the different carbon fiber morphologies in the carbon fiber prepreg, the carbon fiber prepreg is divided into carbon fiber square prepreg, 0° carbon fiber prepreg, and 90° carbon fiber prepreg. The carbon fiber filaments in the 0° carbon fiber prepreg are evenly spaced along the 0° direction. The carbon fiber filaments in the 90° carbon fiber prepreg are evenly spaced along the 90° direction.

[0068] Specifically, when the carbon fiber is carbon fiber square cloth, the carbon fiber prepreg is carbon fiber square prepreg. The carbon fiber composite material for manufacturing special shoe tips is formed by hot pressing several carbon fiber square prepregs. The content of carbon fiber square cloth in the carbon fiber square prepreg is 60 - 63 wt%, and the content of carbon nanotubes is 0.70 - 0.75 wt%. The organizational structure of the carbon fiber square cloth can be selected from plain weave, satin weave, twill weave, and football weave. [[ID=^]]

[0069] The organizational structure of the carbon fiber square cloth is preferably plain weave, which can ensure the mechanical properties of the carbon fiber safety shoe tip.

[0070] The thickness of the carbon fiber square prepreg depends on the specifications of the carbon fiber yarn used as the warp and the carbon fiber yarn used as the weft. The thickness of the carbon fiber square prepreg is generally 0.2 - 0.8 mm, and the gram weight of the carbon fiber square cloth in the carbon fiber square prepreg is 100 - 600 g / m 2 . The specifications of the carbon fiber in the carbon fiber square cloth are any one or a combination of 1K, 3K, 6K, 12K, and 24K.

[0071] Specifically, when the carbon fiber is carbon fiber square cloth and 0° carbon fiber filaments, the carbon fiber prepreg is carbon fiber square prepreg and 0° carbon fiber prepreg. The carbon fiber composite material for manufacturing special shoe tips is formed by hot pressing a number of carbon fiber square prepregs and a number of 0° carbon fiber prepregs. The carbon fiber filaments uniformly arranged at equal intervals in the 0° direction in the 0° carbon fiber prepreg are of any one or more combinations of the specifications of 1K, 3K, 6K, 12K, and 24K. Preferably, the carbon fiber filaments uniformly arranged at equal intervals in the 0° direction in the 0° carbon fiber prepreg are of the specification of 12K. The content of the carbon fiber filaments in the 0° carbon fiber prepreg is 60 - 63 wt%, and the content of the carbon nanotubes is 0.70 - 0.75 wt%.

[0072] Specifically, when the carbon fiber is carbon fiber square cloth and 90° carbon fiber filaments, the carbon fiber prepreg is carbon fiber square prepreg and 90° carbon fiber prepreg. The carbon fiber composite material for manufacturing special shoe tips is formed by hot pressing a number of carbon fiber square prepregs and a number of 90° carbon fiber prepregs. The carbon fiber filaments uniformly arranged at equal intervals in the 90° direction in the 90° carbon fiber prepreg are of any one or more combinations of the specifications of 1K, 3K, 6K, 12K, and 24K. Preferably, the carbon fiber filaments uniformly arranged at equal intervals in the 90° direction in the 90° carbon fiber prepreg are of the specification of 12K. The content of the carbon fiber filaments in the 90° carbon fiber prepreg is 60 - 63 wt%, and the content of the carbon nanotubes is 0.70 - 0.75 wt%.

[0073] Specifically, when the carbon fiber is carbon fiber square cloth, 0° carbon fiber filaments and 90° carbon fiber filaments, the carbon fiber prepreg is carbon fiber square prepreg, 0° carbon fiber prepreg and 90° carbon fiber prepreg. The carbon fiber composite material for manufacturing special shoe tips is formed by hot pressing a number of carbon fiber square prepregs, a number of 0° carbon fiber prepregs and a number of 90° carbon fiber prepregs.

[0074] Due to the different specifications of the carbon fiber filaments, the thicknesses of the prepared carbon fiber square cloth, 0° carbon fiber filaments and 90° carbon fiber filaments are different, and the quantities of the carbon fiber square cloth, 0° carbon fiber filaments and 90° carbon fiber filaments used in the carbon fiber composite material for manufacturing special shoe tips are also different, which will affect the comprehensive performance of the final carbon fiber composite material.

[0075] According to the different limited carbon fiber specifications in the 0° carbon fiber prepreg, 90° carbon fiber prepreg and carbon fiber square prepreg, the thicknesses of the 0° carbon fiber prepreg, 90° carbon fiber prepreg and carbon fiber square prepreg are also different, which will affect the stacking quantities of the 0° carbon fiber prepreg, 90° carbon fiber prepreg and carbon fiber square prepreg, resulting in differences in the mechanical properties and electrical conductivity of the prepared carbon fiber safety shoe tips. Meeting the protection standard of EN 22568 can meet personalized customization.

[0076] The carbon nanotubes are at least one of hydroxyl-modified carbon nanotubes and amino-modified carbon nanotubes. The hydroxylation and / or amination modification on the surface of the carbon nanotubes improves the compatibility between the carbon nanotubes and the matrix resin, enabling the carbon nanotubes to be uniformly dispersed inside the matrix resin, forming a three-dimensional network conductive structure, which not only improves the overall compressive strength and impact strength, but also enhances the overall electrical conductivity and antistatic performance, can effectively eliminate the harm of human static electricity, and better meet the electrostatic protection requirements of the electronics industry.

[0077] The addition amount of the carbon nanotubes will affect the overall antistatic performance. When the carbon nanotubes are less than 0.6 wt%, the decline amplitude of the overall electrical conductivity and antistatic performance is large, making the overall antistatic performance fail to meet the standard. Although when the carbon nanotubes are less than 0.8 wt%, it can improve the overall antistatic performance and mechanical strength, but it will lead to an increase in the overall production cost, which is not conducive to mass production and manufacturing.

[0078] A preparation method of a carbon fiber composite material for manufacturing a special shoe toe includes the following steps:

[0079] Step 1, prepare a carbon fiber prepreg;

[0080] Step 2, cure the carbon fiber prepreg in Step 1 at 40 - 50 °C for 36 - 48 h;

[0081] Step 3, cut the cured carbon fiber prepreg to obtain a finished carbon fiber prepreg that fits the shape of the forming mold. The finished carbon fiber prepreg is stacked into a preformed shoe toe by the manual lay-up method, and after hot pressing and molding, demolding and trimming can obtain the finished carbon fiber safety shoe toe.

[0082] Preferably, the carbon fiber prepreg in Step 1 is a carbon fiber square prepreg, and the preparation method of the carbon fiber square prepreg is as follows:

[0083] S1. Perform surface active functional group modification treatment on the carbon fiber square cloth; at the same time, uniformly mix the accurately measured matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, demolding agent, and carbon nanotubes to obtain a mixture, and coat the mixture on the release paper for semi-curing treatment to obtain a plastic resin film;

[0084] S2. Preheat and press two plastic resin films on the upper and lower surfaces of the carbon fiber square cloth subjected to surface active functional group modification treatment respectively. The mass ratio of the total mass of the two plastic resin films to the mass of the carbon fiber square cloth subjected to surface active functional group modification treatment is (60 - 64):(36 - 40), and then the carbon fiber square prepreg is obtained.

[0085] Preferably, the carbon fiber prepreg in step one is a carbon fiber grid prepreg, and the preparation method of the carbon fiber grid prepreg is as follows: S1. Perform surface active functional group modification treatment on the carbon fiber grid cloth; at the same time, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes and mix them evenly to obtain a mixture; S2. Scrapingly coat the mixture on the upper and lower surfaces of the carbon fiber grid cloth subjected to surface active functional group modification treatment, and dry and semi-cure it to obtain the carbon fiber grid prepreg. The mass ratio of the carbon fiber grid cloth subjected to surface active functional group modification treatment to the mixture in the carbon fiber grid prepreg is (60-64):(36-40).

[0086] Preferably, the carbon fiber prepreg in step one includes a 0° carbon fiber prepreg, and the preparation method of the 0° carbon fiber prepreg is as follows:

[0087] S1. Perform surface active functional group modification treatment on the carbon fiber filaments;

[0088] At the same time, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes and mix them evenly to obtain a mixture. Coating the mixture on the release paper and performing semi-curing treatment to obtain a plastic resin film;

[0089] S2. Thread the carbon fiber filaments modified with surface active functional groups between two yarn guiding plates. The carbon fiber filaments between the yarn guiding plates are evenly spaced along the 0° direction. Preheat and press the plastic resin film on the upper and lower surfaces of the 0° carbon fiber filament layer modified with surface active functional groups between the two yarn guiding plates respectively to obtain the 0° carbon fiber prepreg. The addition amount of the 0° carbon fiber filaments in the 0° carbon fiber prepreg is 60-64wt%.

[0090] Preferably, the carbon fiber prepreg in step one includes a 90° carbon fiber prepreg, and the preparation method of the 90° carbon fiber prepreg is as follows:

[0091] S1. Perform surface active functional group modification treatment on the carbon fiber filaments;

[0092] At the same time, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes and mix them evenly to obtain a mixture. Coating the mixture on the release paper and performing semi-curing treatment to obtain a plastic resin film;

[0093] S2. Thread the carbon fiber filaments modified with surface active functional groups between two yarn guiding plates. The carbon fiber filaments between the yarn guiding plates are evenly spaced and arranged in the 90° direction. Preheat and press the plastic resin film onto the upper and lower surfaces of the 90° carbon fiber filament layer treated with surface active functional groups between the two yarn guiding plates respectively, and then the 90° carbon fiber prepreg can be obtained. The addition amount of the 90° carbon fiber filaments in the 90° carbon fiber prepreg is 60-64wt%.

[0094] Example 1: The carbon fiber composite material for manufacturing special shoe tips is obtained by hot pressing several carbon fiber square prepregs. The carbon fiber square prepreg is made from the following raw materials in parts by weight: 62.5 parts of carbon fiber square cloth (12k carbon fiber reinforced plain cloth, gram weight 400g / m 2 , thickness 0.42mm), 22.321 parts of methyl methacrylate (CAS No.: 2210-28-8), 4.464 parts of epoxy modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.112 parts of initiator BPO (CAS No.: 94-36-0), 0.089 parts of tetraisopropyl titanate (CAS No.: 546-68-9), 0.246 parts of crosslinking agent - dipropylene glycol diacrylate, 4.241 parts of styrene (CAS No.: 100-42-5), 0.536 parts of magnesium oxide (325 mesh, CAS No.: 1309-48-4), 0.313 parts of defoaming agent - BYK 051N defoaming agent, 1.116 parts of zinc stearate (325 mesh, CAS No.: 557-05-1‌‌), 0.714 parts of carbon nanotube TNGMC2.

[0095] The 12k carbon fiber reinforced plain cloth is a carbon fiber square cloth with a plain weave structure woven from Toho HTS40 F13 12K carbon fiber yarns, with warp and weft density of 3.7*3.7, gram weight 400g / m 2 , thickness 0.42mm.

[0096] The epoxy modified acrylic resin WDS-6225, brand LQ, viscosity (at 60℃) 600-1200.

[0097] The carbon nanotube TNGMC2, from Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, OD: 8-15 nanometers, length 10-50 microns, -COOH content 1.28wt%.

[0098] A preparation method of a carbon fiber composite material for manufacturing special shoe tips, comprising the following steps:

[0099] Step 1, prepare the carbon fiber square prepreg:

[0100] Preparation of finished carbon fiber square cloth: Cut the carbon fiber square cloth (12k carbon fiber reinforced plain cloth, with a gram weight of 400 g / m 2 , and a thickness of 0.42 mm) into pieces of 300 mm * 300 mm. Place it in the low-temperature plasma surface treatment instrument NE PE-10, adjust the temperature to 4 ± 0.5 °C, the frequency of the plasma emitter to 40 KHz, and the power to 600 W. Use air as the low-temperature plasma gas source to perform low-temperature plasma treatment on the 12k carbon fiber reinforced plain cloth for 60 s. Take out the 12k carbon fiber reinforced plain cloth, turn it over and then place it back in the low-temperature plasma surface treatment instrument NEPE-10. Adjust the temperature to 4 ± 0.5 °C, the frequency of the plasma emitter to 40 KHz, and the power to 600 W. Use air as the low-temperature plasma gas source to perform low-temperature plasma treatment on the 12k carbon fiber reinforced plain cloth for 60 s, and then the finished carbon fiber square cloth can be obtained;

[0101] Meanwhile, prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoaming agent, 1.116 parts of zinc stearate, and 0.714 parts of carbon nanotube TNGMC2 into the reaction kettle. Stir and defoam under nitrogen protection for 45 min. After defoaming, add 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin;

[0102] Uniformly scrape 10.8 g of the impregnating resin on one surface of the finished carbon fiber square cloth, and then uniformly scrape 10.8 g of the impregnating resin on the other surface of the finished carbon fiber square cloth. Then, attach release paper to both sides to obtain the carbon fiber square prepreg;

[0103] Step two, cure the carbon fiber square prepreg obtained in step one at 40 °C for 36 h;

[0104] Step three, cut the carbon fiber square prepreg cured in step two to obtain the finished carbon fiber prepreg that fits the shape of the forming mold. Stack the finished carbon fiber prepreg into a preformed toe cap by the manual lay-up method, and perform hot pressing forming treatment using a mold. The hot pressing parameters are: hot press at 145 °C and a pressure of 50 kg for 10 min. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety toe cap.

[0105] The difference between Example 2 and Example 1 is that the preparation method of the carbon fiber composite material used to manufacture the special toe cap is as follows. Step one, prepare the carbon fiber square prepreg:

[0106] Preparation of finished carbon fiber square cloth: Cut the carbon fiber square cloth (12k carbon fiber reinforced plain cloth, gram weight 400g / m 2 , thickness 0.42mm) into 300mm * 300mm, place it in the low-temperature plasma surface treatment instrument NE PE-10, adjust the temperature to 4 ± 0.5°C, the frequency of the plasma emitter is 40KHz, the power is 600W, use air as the low-temperature plasma gas source, perform 60s low-temperature plasma treatment on the 12k carbon fiber reinforced plain cloth, take out the 12k carbon fiber reinforced plain cloth, turn it over and then place it in the low-temperature plasma surface treatment instrument NE PE-10, adjust the temperature to 4 ± 0.5°C, the frequency of the plasma emitter is 40KHz, the power is 600W, use air as the low-temperature plasma gas source, perform 60s low-temperature plasma treatment on the 12k carbon fiber reinforced plain cloth, and the finished carbon fiber square cloth can be obtained;

[0107] Meanwhile, prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoaming agent, 1.116 parts of zinc stearate, 0.714 parts of carbon nanotube TNGMC2 into the reaction kettle, stir and defoam for 45min under nitrogen protection, after defoaming is completed, add 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin;

[0108] Evenly scrape 10.8g of the impregnating resin on the surface of 300mm * 300mm release paper, pre-cure at 80°C for 90s to obtain an impregnating resin film sheet for standby; Preheat and press two impregnating resin film sheets on the upper and lower surfaces of the finished carbon fiber square cloth respectively, pre-cure at 80°C for 30s to obtain a carbon fiber square pre-impregnated cloth for standby;

[0109] Step two, cure the carbon fiber square pre-impregnated cloth in step one at 40°C for 36h;

[0110] Step three, cut the carbon fiber square pre-impregnated cloth cured in step two to obtain a finished carbon fiber pre-impregnated cloth that fits the shape of the forming mold, stack the finished carbon fiber pre-impregnated cloth into a preformed toe cap by the manual layering method, and perform hot pressing forming treatment with a mold. Hot pressing parameters: hot press at 145°C and a pressure of 50kg for 10min, demold after cooling to room temperature, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety toe cap.

[0111] The difference between Example 3 and Example 2 is as follows: In the preparation of the carbon fiber square pre-impregnated cloth in Step 1, 12 g of impregnating resin was evenly scrape-coated on the surface of a 300 mm * 300 mm release paper, and pre-cured at 80 °C for 90 s to obtain an impregnating resin film for standby; two pieces of plastic resin film were respectively pre-heated and pressed on the upper and lower surfaces of the finished carbon fiber square cloth, and pre-cured at 80 °C for 30 s to obtain the carbon fiber square pre-impregnated cloth for standby.

[0112] The difference between Example 4 and Example 2 is as follows: In the preparation of the carbon fiber square pre-impregnated cloth in Step 1, 10.1 g of impregnating resin was evenly scrape-coated on the surface of a 300 mm * 300 mm release paper, and pre-cured at 80 °C for 90 s to obtain an impregnating resin film for standby; two pieces of plastic resin film were respectively pre-heated and pressed on the upper and lower surfaces of the finished carbon fiber square cloth, and pre-cured at 80 °C for 30 s to obtain the carbon fiber square pre-impregnated cloth for standby.

[0113] The difference between Example 5 and Example 2 is as follows: In Step 3, the carbon fiber square pre-impregnated cloth after the curing treatment in Step 2 was cut into a finished carbon fiber pre-impregnated cloth that fits the shape of the forming mold. The finished carbon fiber pre-impregnated cloth was stacked into a preformed toe cap with a thickness of 6.0 mm by the manual layering method, and hot-pressed and formed using a mold. The hot-pressing parameters were: hot-pressing at 145 °C and a pressure of 50 kg for 10 min. After cooling to room temperature, demolding, cutting and trimming, and polishing the edges, the finished carbon fiber safety toe cap was obtained. The thickness of the preformed toe cap in Example 2 was 8.0 mm.

[0114] The difference between Comparative Example 1 and Example 1 is as follows: In the preparation of the carbon fiber square pre-impregnated cloth in Step 1, 9.4 g of impregnating resin was evenly scrape-coated on the surface of a 300 mm * 300 mm release paper, and pre-cured at 80 °C for 90 s to obtain an impregnating resin film for standby; two pieces of plastic resin film were respectively pre-heated and pressed on the upper and lower surfaces of the finished carbon fiber square cloth, and pre-cured at 80 °C for 30 s to obtain the carbon fiber square pre-impregnated cloth for standby.

[0115] The difference between Comparative Example 2 and Example 1 is as follows: In the preparation of the carbon fiber square pre-impregnated cloth in Step 1, 12.5 g of impregnating resin was evenly scrape-coated on the surface of a 300 mm * 300 mm release paper, and pre-cured at 80 °C for 90 s to obtain an impregnating resin film for standby; two pieces of plastic resin film were respectively pre-heated and pressed on the upper and lower surfaces of the finished carbon fiber square cloth, and pre-cured at 80 °C for 30 s to obtain the carbon fiber square pre-impregnated cloth for standby.

[0116] The difference between Comparative Example 3 and Example 1 lies in that the glass fiber composite material used to manufacture the special toe cap is prepared by hot pressing a number of glass fiber square cloth prepregs. The glass fiber square cloth prepreg is made from the following raw materials in parts by weight: 62.5 parts of EWR400 glass fiber mesh cloth, 22.321 parts of methyl methacrylate, 4.464 parts of epoxy modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.112 parts of initiator BPO, 0.089 parts of tetraisopropyl titanate, 0.246 parts of crosslinking agent - dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of defoaming agent - BYK 051N defoaming agent, 1.116 parts of zinc stearate, 0.714 parts of carbon nanotube TNGMC2.

[0117] A glass fiber composite material for manufacturing a special toe cap, comprising the following steps:

[0118] Step 1, preparing a glass fiber square cloth prepreg:

[0119] Preparing an impregnating resin: Placing 22.321 parts of methyl methacrylate, 4.464 parts of epoxy modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoaming agent, 1.116 parts of zinc stearate, 0.714 parts of carbon nanotube TNGMC2 into a reaction kettle, stirring and degassing for 45 min under nitrogen protection. After degassing is completed, add 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin;

[0120] Evenly scrape 10.8 g of the impregnating resin onto one surface of an EWR400 glass fiber mesh cloth with a specification of 300*300 mm, and then evenly scrape 10.8 g of the impregnating resin onto the other surface of the EWR400 glass fiber mesh cloth. Pre-cure at 80°C for 120 s, and laminate release paper on both sides to obtain the glass fiber square cloth prepreg;

[0121] Step 2, curing the glass fiber square cloth prepreg in Step 1 at 40°C for 36 h;

[0122] Step 3, cutting the carbon fiber square prepreg after the curing treatment in Step 2 to obtain a finished carbon fiber prepreg that fits the shape of the forming mold. Stack the finished carbon fiber prepreg into a preformed toe cap by the manual layering method, and perform hot pressing molding treatment using a mold. Hot pressing parameters: hot press at 145°C and a pressure of 50 kg for 10 min. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety toe cap.

[0123] The difference between Comparative Example 4 and Example 1 lies in that carbon nanotubes are not added to the carbon fiber square prepreg. Specifically, the carbon fiber square prepreg is made from the following raw materials in parts by weight: 62.5 parts of carbon fiber square cloth (12k carbon fiber reinforced plain cloth, with a grammage of 400 g / m 2 , with a thickness of 0.42 mm), 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.112 parts of initiator BPO, 0.089 parts of tetraisopropyl titanate, 0.246 parts of crosslinking agent - dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of defoaming agent - BYK051N defoaming agent, 1.116 parts of zinc stearate, 0.714 parts of carbon black (Mitsubishi carbon black #3400B).

[0124] Performance detection test: The sizes of the carbon fiber safety toe caps and fiberglass safety shoes tested are size 8#.

[0125] 1. Residual height (mm) after 200J impact: Measured in accordance with the requirements of European standard EN 22568-2019.

[0126] 2. Residual height (mm) after 15kN impact: Measured in accordance with the requirements of European standard EN 22568-2019.

[0127] 3. Antistatic test method: Use a surface resistance tester Metriso 3000 to measure the surface resistance of the carbon fiber safety toe cap. If the surface resistance of the carbon fiber safety toe cap ≤ 10 9 Ω / m², then the antistatic performance of the carbon fiber safety toe cap is good, recorded as qualified PASS. If the surface resistance of the carbon fiber safety toe cap is greater than 10 9 Ω / m², then the carbon fiber safety toe cap does not have antistatic performance, recorded as unqualified NG.

[0128] 4. Anti-puncture performance: Use a PL test needle for puncture test. The diameter of the PL test needle is 4.5 mm, the needle tip is a cone with an angle of (30 ± 2)°, the truncated tip has a diameter of (1 ± 0.02) mm, and the total length ≥ 80 mm. Randomly select 4 puncture points for testing. When the puncture force value reaches 1100 N, there should be no penetration and material delamination. If all 4 test points pass, it is recorded as qualified PASS, otherwise it is unqualified NG.

[0129] 5. Abrasion resistance: Use a Martindale abrasion tester, with 180# sandpaper as the abrasive, and under the condition of a pressure of 9 kPa, test whether the carbon fiber composite material is worn through after 8000 revolutions. If it is not worn through, it is recorded as qualified PASS, otherwise it is unqualified NG.

[0130] Table 1: Tolerance performance parameter table of carbon fiber shoe tips in Examples 1-5 and Comparative Examples 1-4

[0131]

[0132] Table 2: Mechanical parameter table of carbon fiber shoe tips in Examples 1-5 and Comparative Examples 1-4

[0133]

[0134] Combining Examples 2-4 and Comparative Examples 1-2 and referring to Tables 1-2, it can be seen that when the content of carbon fiber square cloth in the carbon fiber square pre-impregnated cloth is controlled at 60-64 wt%, it can ensure that the carbon fiber safety shoe tip has good compressive strength and impact strength. When the content of carbon fiber square cloth in the carbon fiber square pre-impregnated cloth is less than 60 wt%, the internal clearance height after 15 kN compression of the carbon fiber safety shoe tip is less than 30 mm, which has an adverse effect on the overall compressive strength, and the internal clearance height after 200 J impact also drops from 29.0 mm to 27.8 - 27.8 mm, which has an adverse effect on the overall impact strength.

[0135] Combining Example 2 and Comparative Example 3 and referring to Tables 1-2, it can be seen that the addition of carbon nanotubes can improve the antistatic performance, wear resistance and impact strength of the carbon fiber safety shoe tip.

[0136] Combining Example 2 and Comparative Examples 3-4 and referring to Tables 1-2, it can be seen that the addition of carbon nanotubes has a better effect on improving the wear resistance and impact strength of the carbon fiber safety shoe tip than carbon black. The reason is that the carbon nanotubes with high aspect ratio can effectively conduct the carbon fiber square cloth in the matrix of the carbon fiber shoe tip to form a three-dimensional network-shaped conductive skeleton. That is, by adding carbon nanotubes to the carbon fiber square pre-impregnated cloth formula, the antistatic performance, wear resistance and impact strength of the carbon fiber safety shoe tip can be better improved.

[0137] Combining Examples 1-4 and Comparative Examples 1-2 and referring to Tables 1-2, it can be seen that the carbon fiber safety shoe tip prepared with the pre-impregnated resin formula provided in the present invention has good compressive strength and impact strength, and also has good antistatic performance, with a surface resistance ≤ 10 7 Ω / m², which can meet the electrostatic protection requirements of the electronics industry.

[0138] The difference between Example 6 and Example 2 is that the carbon fiber composite material used to manufacture the special shoe tip is obtained by hot pressing several carbon fiber square pre-impregnated cloths and 0° carbon fiber pre-impregnated cloths. The carbon fiber square pre-impregnated cloth used in Example 6 is the same as that used in Example 2.

[0139] The 0° carbon fiber prepreg is made of 62.5 parts of Toho HTS40 F13 12K carbon fiber yarn, 22.321 parts of propyl methacrylate (CAS No.: 2210-28-8), 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.112 parts of initiator BPO (CAS No.: 94-36-0), 0.089 parts of titanium tetraisopropoxide (CAS No.: 546-68-9), 0.246 parts of crosslinker - dipropylene glycol diacrylate, 4.241 parts of styrene (CAS No.: 100-42-5), 0.536 parts of magnesium oxide (325 mesh, CAS No.: 1309-48-4), 0.313 parts of defoamer - BYK 051N defoamer, 1.116 parts of zinc stearate (325 mesh, CAS No.: 557-05-1‌‌), and 0.714 parts of carbon nanotube TNGMC2.

[0140] A carbon fiber composite material for manufacturing special shoe tips, comprising the following steps:

[0141] Step 1, the preparation method of the carbon fiber grid prepreg is the same as that of the carbon fiber grid prepreg in Example 2, that is, the carbon fiber grid prepreg used in Example 6 is the same as the carbon fiber grid prepreg used in Example 2;

[0142] At the same time, prepare the 0° carbon fiber prepreg:

[0143] The first step, preparation of surface active functional group modified carbon fiber yarn: Select Toho HTS40 F13 12K carbon fiber yarn, untwist the Toho HTS40 F13 12K carbon fiber yarn for 10 turns, then place the untwisted Toho HTS40 F13 12K carbon fiber yarn in hydrogen peroxide for ultrasonic modification treatment for 10 min, the frequency of the ultrasonic emitter is 40 kHz, the power is 600 W, then input it into the oven and dry it at 80°C for 1 hour, twist the dried surface active functional group modified carbon fiber yarn for 10 turns and wind it up to obtain the surface active functional group modified carbon fiber yarn, and the surface active functional group modified carbon fiber yarn contains active hydroxyl -OH and active carboxyl -COOH.

[0144] Meanwhile, prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoamer, 1.116 parts of zinc stearate, and 0.714 parts of carbon nanotube TNGMC2 into a reaction kettle. Under nitrogen protection, stir and degas for 45 minutes. After degassing is completed, add 0.112 parts of initiator BPO and 0.089 parts of tetra-isopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin. Spread 58.8 g of the impregnating resin evenly on a release paper of 900 mm * 900 mm, and pre-cure at 80 °C for 90 s to obtain a prepreg resin film for standby;

[0145] In the second step, thread the surface-active functional group-modified Toho HTS40 F13 12K carbon fiber yarn between two yarn guiding plates. The length of the yarn guiding plates is 900 mm, and the distance between the two yarn guiding plates is 900 mm. The carbon fiber filaments between the yarn guiding plates are evenly spaced along the 0° direction. The amount of Toho HTS40 F13 12K carbon fiber yarn used is 196 g. Respectively preheat and press the prepreg resin film with a specification of 900 mm * 900 mm on the upper and lower surfaces of the 0° carbon fiber filament layer with surface-active functional group modification between the two yarn guiding plates, and pre-cure at 80 °C for 30 s to obtain a 0° carbon fiber prepreg with a thickness of 0.30 ± 0.02 mm;

[0146] Step 2: Cure the carbon fiber prepreg in Step 1 at 40 °C for 36 h;

[0147] Step 3: Cut the carbon fiber square prepreg after the curing treatment in Step 2 to obtain a finished carbon fiber prepreg that fits the shape of the molding die. Stack the finished carbon fiber prepreg into a preformed shoe tip by the manual lay-up method. The stacking method is as follows: Mark the carbon fiber square prepreg as A and the 0° carbon fiber prepreg as B. The specific structure of the prefabricated sheet is as follows: AAA / B / AAA / B / AAAA / B / AAA / B / AAA. Perform hot pressing and molding treatment using a mold. Hot pressing parameters: Hot press at 145 °C and a pressure of 50 kg for 10 minutes. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety shoe tip.

[0148] The difference between Example 7 and Example 2 is that the carbon fiber composite material used to manufacture the special shoe tip is obtained by hot pressing and molding several carbon fiber square prepregs and 90° carbon fiber prepregs. The carbon fiber square prepreg used in Example 7 is the same as the carbon fiber square prepreg used in Example 2

[0149] The 90° carbon fiber prepreg is made of 62.5 parts of Toho HTS40 F13 12K carbon fiber yarn, 22.321 parts of propyl methacrylate (CAS No.: 2210-28-8), 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.112 parts of initiator BPO (CAS No.: 94-36-0), 0.089 parts of tetraisopropyl titanate (CAS No.: 546-68-9), 0.246 parts of crosslinking agent - dipropylene glycol diacrylate, 4.241 parts of styrene (CAS No.: 100-42-5), 0.536 parts of magnesium oxide (325 mesh, CAS No.: 1309-48-4), 0.313 parts of defoaming agent - BYK 051N defoaming agent, 1.116 parts of zinc stearate (325 mesh, CAS No.: 557-05-1‌‌), and 0.714 parts of carbon nanotube TNGMC2.

[0150] A carbon fiber composite material for manufacturing special shoe tips, comprising the following steps:

[0151] Step 1, the preparation method of the carbon fiber square prepreg is the same as that of the carbon fiber square prepreg in Example 2, that is, the carbon fiber square prepreg used in Example 6 is the same as the carbon fiber square prepreg used in Example 2;

[0152] At the same time, prepare 90° carbon fiber prepreg:

[0153] The first step, the preparation of surface active functional group modified carbon fiber yarn: Select Toho HTS40 F13 12K carbon fiber yarn, untwist the Toho HTS40 F13 12K carbon fiber yarn for 10 turns, then place the untwisted Toho HTS40 F13 12K carbon fiber yarn in hydrogen peroxide for ultrasonic modification treatment for 10 min, the frequency of the ultrasonic emitter is 40 kHz, the power is 600 W, then input it into the oven and dry it at 80 °C for 1 hour, twist the dried surface active functional group modified carbon fiber yarn for 10 turns and wind it up to obtain the surface active functional group modified carbon fiber yarn, which contains active hydroxyl -OH and active carboxyl -COOH on its surface.

[0154] Meanwhile, prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoamer, 1.116 parts of zinc stearate, and 0.714 parts of carbon nanotube TNGMC2 into the reaction kettle. Under nitrogen protection, stir and degas for 45 minutes. After degassing is completed, add 0.112 parts of initiator BPO and 0.089 parts of tetra-isopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin. Spread 58.8 g of the impregnating resin evenly on the release paper of 900 mm * 900 mm, and pre-cure at 80 °C for 90 s to obtain the prepreg resin film for standby;

[0155] In the second step, thread the surface-active functional group-modified Toho HTS40 F13 12K carbon fiber yarn between two yarn guiding plates. The length of the yarn guiding plate is 900 mm, and the spacing between the two yarn guiding plates is 900 mm. The carbon fiber filaments between the yarn guiding plates are evenly arranged at intervals along the 90° direction. The amount of Toho HTS40 F13 12K carbon fiber yarn used is 196 g. Respectively preheat and press the prepreg resin film with the specification of 900 mm * 900 mm on the upper and lower surfaces of the 90° carbon fiber filament layer with surface-active functional group modification between the two yarn guiding plates, and pre-cure at 80 °C for 30 s to obtain a 90° carbon fiber prepreg with a thickness of 0.30 ± 0.02 mm;

[0156] Step 2: Cure the carbon fiber prepreg in Step 1 at 40 °C for 36 h;

[0157] Step 3: Cut the carbon fiber square prepreg after the curing treatment in Step 2 to obtain a finished carbon fiber prepreg that fits the shape of the forming mold. Stack the finished carbon fiber prepreg into a preformed toe cap by the manual layering method. The stacking method is as follows: Mark the carbon fiber square prepreg as A and the 90° carbon fiber prepreg as C. The specific structure of the prefabricated sheet is as follows: AAA / C / AAA / C / AAAA / C / AAA / C / AAA. Perform hot pressing and forming treatment with a mold. The hot pressing parameters are: hot pressing at 145 °C and a pressure of 50 kg for 10 minutes. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety toe cap.

[0158] The difference between Example 9 and Example 2 is that the carbon fiber composite material used to manufacture the special toe cap is obtained by hot pressing and forming several carbon fiber square prepregs, 0° carbon fiber prepregs, and 90° carbon fiber prepregs. The carbon fiber square prepreg used in Example 9 is the same as the carbon fiber square prepreg used in Example 2.

[0159] The 0° carbon fiber prepreg is made of 62.5 parts of Toho HTS40 F13 12K carbon fiber yarn, 22.321 parts of propyl methacrylate (CAS No.: 2210-28-8), 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.112 parts of initiator BPO (CAS No.: 94-36-0), 0.089 parts of tetraisopropyl titanate (CAS No.: 546-68-9), 0.246 parts of crosslinker - dipropylene glycol diacrylate, 4.241 parts of styrene (CAS No.: 100-42-5), 0.536 parts of magnesium oxide (325 mesh, CAS No.: 1309-48-4), 0.313 parts of defoamer - BYK 051N defoamer, 1.116 parts of zinc stearate (325 mesh, CAS No.: 557-05-1‌‌), and 0.714 parts of carbon nanotube TNGMC2.

[0160] The 90° carbon fiber prepreg is made of 62.5 parts of Toho HTS40 F13 12K carbon fiber yarn, 22.321 parts of propyl methacrylate (CAS No.: 2210-28-8), 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.112 parts of initiator BPO (CAS No.: 94-36-0), 0.089 parts of tetraisopropyl titanate (CAS No.: 546-68-9), 0.246 parts of crosslinker - dipropylene glycol diacrylate, 4.241 parts of styrene (CAS No.: 100-42-5), 0.536 parts of magnesium oxide (325 mesh, CAS No.: 1309-48-4), 0.313 parts of defoamer - BYK 051N defoamer, 1.116 parts of zinc stearate (325 mesh, CAS No.: 557-05-1‌‌), and 0.714 parts of carbon nanotube TNGMC2.

[0161] A carbon fiber composite material for manufacturing special shoe tips includes the following steps:

[0162] Step 1, the preparation method of the carbon fiber square prepreg is the same as that of the carbon fiber square prepreg in Example 2, that is, the carbon fiber square prepreg used in Example 9 is the same as the carbon fiber square prepreg used in Example 2;

[0163] At the same time, prepare the 0° carbon fiber prepreg:

[0164] Step 1: Preparation of surface-active functional group modified carbon fiber yarn: Select Toho HTS40 F13 12K carbon fiber yarn, untwist the Toho HTS40 F13 12K carbon fiber yarn for 10 turns, then place the untwisted Toho HTS40 F13 12K carbon fiber yarn in hydrogen peroxide for ultrasonic modification treatment for 10 min. The frequency of the ultrasonic emitter is 40 kHz and the power is 600 W. Then input it into the oven and dry it at 80°C for 1 hour. Twist the dried surface-active functional group modified carbon fiber yarn for 10 turns and wind it up to obtain the surface-active functional group modified carbon fiber yarn. The surface-active functional group modified carbon fiber yarn contains active hydroxyl groups -OH and active carboxyl groups -COOH.

[0165] Meanwhile, prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoamer, 1.116 parts of zinc stearate, and 0.714 parts of carbon nanotube TNGMC2 into the reaction kettle, stir and degas under nitrogen protection for 45 min. After degassing, add 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin. Spread 58.8 g of the impregnating resin evenly on the release paper of 900 mm * 900 mm and pre-cure it at 80°C for 90 s to obtain the prepreg resin film for standby.

[0166] Step 2: Thread the surface-active functional group modified Toho HTS40 F13 12K carbon fiber yarn between two yarn guides. The length of the yarn guide is 900 mm and the distance between the two yarn guides is 900 mm. The carbon fiber filaments between the yarn guides are evenly spaced along the 0° direction. The amount of Toho HTS40 F13 12K carbon fiber yarn used is 196 g. Respectively preheat and press the prepreg resin film with the specification of 900 mm * 900 mm on the upper and lower surfaces of the 0° carbon fiber filament layer with surface-active functional group modification treatment between the two yarn guides, and pre-cure it at 80°C for 30 s to obtain a 0° carbon fiber prepreg with a thickness of 0.30 ± 0.02 mm.

[0167] Meanwhile, prepare 90° carbon fiber prepreg. The difference in the preparation method between the 90° carbon fiber prepreg and the 0° carbon fiber prepreg lies in the second step. In the second step, the Toray HTS40 F13 12K carbon fiber yarn modified with surface active functional groups is threaded between two yarn guiding plates. The length of the yarn guiding plates is 900 mm, the distance between the two yarn guiding plates is 900 mm, and the carbon fiber filaments between the yarn guiding plates are evenly spaced along the 90° direction. The amount of Toray HTS40 F13 12K carbon fiber yarn used is 196 g. The prepreg resin films with the specification of 900 mm * 900 mm are respectively preheated and pressed on the upper and lower surfaces of the 90° carbon fiber filament layer modified with surface active functional groups between the two yarn guiding plates, and pre-cured at 80°C for 30 s to obtain the 90° carbon fiber prepreg with a thickness of 0.30 ± 0.02 mm;

[0168] Step 2, the carbon fiber prepreg in Step 1 is cured at 40°C for 36 h;

[0169] Step 3, cut the carbon fiber square prepreg cured in Step 2 into a finished carbon fiber prepreg that fits the shape of the molding die. Stack the finished carbon fiber prepreg into a preformed toe cap by the manual layering method. The stacking method is as follows: the carbon fiber square prepreg is marked as A, the 0° carbon fiber prepreg is marked as B, and the 90° carbon fiber prepreg is marked as C. The specific structure of the prefabricated sheet is as follows: AAA / C / AAA / B / AAAA / B / AAA / C / AAA. Perform hot pressing and molding treatment using a mold. The hot pressing parameters are: hot pressing at 145°C and a pressure of 50 kg for 10 min. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety toe cap.

[0170] The difference between Example 9 and Example 2 is that the preparation method of the carbon fiber square prepreg in Step 1 is as follows: First step, preparation of the carbon fiber yarn modified with surface active functional groups: Select Toray T400HB-6000 carbon fiber yarn, untwist the Toray T400HB-6000 carbon fiber yarn for 10 turns, then place the untwisted Toray T400HB-6000 carbon fiber yarn in hydrogen peroxide for ultrasonic modification treatment for 10 min. The frequency of the ultrasonic emitter is 40 kHz and the power is 600 W. Then input it into an oven and dry it at 80°C for 1 hour. Twist the dried carbon fiber yarn modified with surface active functional groups for 10 turns and wind it up to obtain the carbon fiber yarn modified with surface active functional groups. The carbon fiber yarn modified with surface active functional groups contains active hydroxyl groups -OH and active carboxyl groups -COOH.

[0171] Meanwhile, prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoamer, 1.116 parts of zinc stearate, and 0.714 parts of carbon nanotube TNGMC2 into a reaction kettle. Under nitrogen protection, stir and degas for 45 minutes. After degassing is completed, add 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin. Spread 60 g of the impregnating resin evenly on a release paper of 1000 mm * 500 mm, and pre-cure at 80 °C for 90 s to obtain a prepreg resin film, and set aside;

[0172] In the second step, the T400HB-6000 carbon fiber yarn modified with surface active functional groups is used as the warp and weft. The warp and weft densities are both 5 roots * 5 roots, and a plain weave is used to weave a carbon fiber square cloth with a gram weight of 400 g / m 2 , with a thickness of 0.42 mm, a width of 500 mm, and a cut length of 1000 mm;

[0173] In the third step, two pieces of impregnating resin film pieces with specifications of 1000 mm * 500 mm are respectively preheated and pressed on the upper and lower surfaces of the carbon fiber square cloth modified with surface active functional groups, and pre-cured at 80 °C for 30 s to obtain a carbon fiber square prepreg. The remaining steps are the same.

[0174] The difference between Example 10 and Example 9 is as follows: In step one, the preparation method of the carbon fiber square prepreg is as follows: In the first step, the specific preparation of the electro-polymerization composite modified carbon fiber yarn is as follows. First, the Toray T400HB-6000 carbon fiber yarn is washed successively with acetone and deionized water; then the washed T400HB-6000 carbon fiber yarn is subjected to electro-polymerization in a three-electrode system, and polyaniline nanosheets are formed on the surface of the carbon fiber yarn by electro-polymerization. Specifically, the washed carbon fiber yarn is used as the working electrode, the platinum sheet is used as the counter electrode, and Ag / AgCl is used as the reference electrode. The electro-polymerization liquid level contains 0.2 M / L of aniline monomer and 0.05 / L of aniline monomer, the cyclic voltage is 1.4 V, the electro-polymerization time is 10 minutes, take it out, rinse three times with deionized water, and dry to obtain the electro-polymerization composite modified carbon fiber yarn T400HB-6000.

[0175] Meanwhile, prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoamer, 1.116 parts of zinc stearate, and 0.714 parts of carbon nanotube TNGMC2 into the reaction kettle. Under nitrogen protection, stir and defoam for 45 min. After defoaming, add 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin. Spread 120 g of the impregnating resin evenly on the release paper of 1000 mm * 1000 mm, and pre-cure at 80 °C for 90 s to obtain the prepreg resin film for standby;

[0176] In the second step, electro-polymerization composite modified carbon fiber yarn T400HB-6000 is used as warp and weft yarns, and the warp and weft densities are both 5 roots * 5 roots. Weave it flatly to obtain a carbon fiber square cloth with a weight of 400 g / m 2 , a thickness of 0.42 mm, a width of 1000 mm, and a cut length of 1000 mm;

[0177] In the third step, preheat and press two pieces of impregnating resin film with specifications of 1000 mm * 1000 mm on the upper and lower surfaces of the carbon fiber square cloth modified with surface active functional groups respectively, and pre-cure at 80 °C for 30 s to obtain the carbon fiber square prepreg. The remaining steps are the same.

[0178] The difference between Example 11 and Example 9 is that in Step 3, the carbon fiber square prepreg obtained by curing treatment in Step 2 is cut into a finished carbon fiber prepreg that fits the shape of the forming mold. The finished carbon fiber prepreg is stacked into a preformed shoe tip by the manual layering method. The stacking method is that the carbon fiber square prepreg is marked as A, the 0° carbon fiber prepreg is marked as B, and the 90° carbon fiber prepreg is marked as C. The specific structure of the prefabricated sheet is as follows: AA / C / AA / B / AAA / B / AA / C / AA. It is processed by hot pressing using a mold. The hot pressing parameters are: hot pressing at 145 °C and a pressure of 50 kg for 10 min. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety shoe tip with a thickness of 6.0 mm.

[0179] The difference between Comparative Example 4 and Example 2 is that in Step 1, prepare the carbon fiber square prepreg:

[0180] Step 1: Prepare the impregnating resin: Put 22.321 parts of propyl methacrylate, 4.464 parts of epoxy-modified acrylic resin WDS-6225, 3.348 parts of polycaprolactone NPG200, 0.246 parts of dipropylene glycol diacrylate, 4.241 parts of styrene, 0.536 parts of magnesium oxide, 0.313 parts of BYK 051N defoamer, 1.116 parts of zinc stearate, and 0.714 parts of carbon nanotube TNGMC2 into a reaction kettle, stir and degas for 45 min under nitrogen protection. After degassing, add 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement, and mix evenly to obtain the impregnating resin;

[0181] Step 2: Uniformly scrape 10.8 g of the impregnating resin on the surface of a 300 mm * 300 mm release paper, and pre-cure it at 80 °C for 90 s to obtain an impregnating resin film sheet for standby;

[0182] Step 3: Preheat and press two impregnating resin film sheets on the upper and lower surfaces of an untreated carbon fiber square cloth (the cut size is 300 mm * 300 mm) respectively, and pre-cure it at 80 °C for 30 s to obtain a carbon fiber square prepreg.

[0183] Table 3: Tolerance performance parameter table of carbon fiber shoe tips in Example 2, Examples 5-7, Examples 9-11, and Comparative Example 4

[0184]

[0185] Table 4: Mechanical parameter table of carbon fiber shoe tips in Example 2, Examples 5-7, Examples 9-11, and Comparative Example 4

[0186]

[0187] Combined with Example 2, Examples 5-11, and Comparative Example 4 and Tables 3-4, it can be seen that the carbon fiber composite material used to manufacture special shoe tips, whether it is hot-pressed and formed by several carbon fiber square prepregs or the carbon fiber shoe tips (with a thickness of 6.0-8.0 mm) prepared by combining several carbon fiber square prepregs with at least one of 0° carbon fiber prepreg and 90° carbon fiber prepreg, all meet the protection standards of European standard EN22568, Canadian standard CSA, and American standard ASTM.

[0188] Combined with Example 2 and Comparative Example 4 and Tables 3-4, it can be seen that without surface modification treatment of the carbon fiber square cloth in the carbon fiber square prepreg, the compatibility between the carbon fiber square cloth and the impregnating resin is affected, resulting in a significant decrease in both the compressive strength and impact strength of the prepared carbon fiber shoe tips.

[0189] Combined with Example 2, Examples 9 - 10 and Table 3 - 4, it can be seen that the carbon fiber toe caps prepared from the carbon fiber square pre - impregnated fabrics in Example 2, Examples 9 - 10 all meet the protection standards of European standard EN 22568, Canadian standard CSA, and American standard ASTM. Moreover, the impact resistance of the carbon fiber toe cap prepared from the carbon fiber square pre - impregnated fabric in Example 9 is better than that of the carbon fiber toe cap prepared from the carbon fiber square pre - impregnated fabric in Example 2.

[0190] Combined with Example 5 and Example 11 and Table 3 - 4, it can be seen that the carbon fiber toe caps prepared from the carbon fiber square pre - impregnated fabrics in Example 5, Example 11 all meet the protection standards of European standard EN 22568, Canadian standard CSA, and American standard ASTM. Moreover, the impact resistance of the carbon fiber toe cap prepared from the carbon fiber square pre - impregnated fabric in Example 11 is better than that of the carbon fiber toe cap prepared from the carbon fiber square pre - impregnated fabric in Example 5.

[0191] Combined with Example 5 and Examples 9 - 10 and Table 3 - 4, it can be seen that the impact resistance of the carbon fiber toe caps prepared from the carbon fiber square pre - impregnated fabrics in Example 10 and Example 11 is better than that of the carbon fiber toe cap prepared from the carbon fiber square pre - impregnated fabric in Example 5. That is, the surface modification treatment method of the carbon fiber square fabric in Examples 9 - 10 is better than that of the carbon fiber square fabric in Example 2; however, the cost of the surface modification treatment method of the carbon fiber square fabric in Example 9 is a bit higher.

[0192] In summary, the safety toe cap prepared from the carbon fiber composite material of the present invention has good compressive strength, impact strength and good electrical conductivity, and can meet the electrostatic protection requirements of the electronics industry.

Claims

1. A carbon fiber composite material for manufacturing special shoe tips, characterized in that: The carbon fiber composite material used for manufacturing special shoe tips is formed by hot pressing several carbon fiber prepregs; the carbon fiber prepregs are made from the following raw materials in parts by weight: 60 - 64 parts of carbon fiber, 25 - 28 parts of matrix resin, 3 - 4 parts of low shrinkage resin, 0.15 - 0.25 parts of initiator, 0.2 - 0.5 parts of crosslinking agent, 4 - 6 parts of styrene, 0.4 - 0.6 parts of magnesium oxide, 0.3 - 0.4 parts of defoaming agent, 1 - 1.5 parts of release agent, 0.6 - 0.8 parts of carbon nanotubes; At least two double bonds are contained in the crosslinking agent; the matrix resin includes at least vinyl resin; the carbon fiber includes at least carbon fiber square cloth; the release agent is at least one of stearate, molybdenum disulfide, talcum powder, and fumed silica; the carbon nanotubes are at least one of hydroxyl - modified carbon nanotubes and amino - modified carbon nanotubes; The preparation method of the carbon fiber prepreg is as follows: Step 1, prepare the carbon fiber prepreg; S1. Perform surface active functional group modification treatment on the carbon fiber square cloth; at the same time, mix the accurately metered matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, release agent, and carbon nanotubes evenly to obtain a mixture, and coat the mixture on the release paper for semi - curing treatment to obtain a plastic resin film; S2. Pre - heat - press two plastic resin films on the upper and lower surfaces of the carbon fiber square cloth with surface active functional group modification treatment respectively. The mass ratio of the total mass of the two plastic resin films to the mass of the carbon fiber square cloth with surface active functional group modification treatment is (36 - 40):(60 - 64), and then the carbon fiber square prepreg can be prepared; Step 2, cure the carbon fiber prepreg obtained in Step 1 at 40 - 50 °C for 36 - 48 h; Or the preparation method of the carbon fiber prepreg is as follows: Step 1, prepare the carbon fiber prepreg; S1. Perform surface active functional group modification treatment on the carbon fiber square cloth; at the same time, mix the accurately metered matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, release agent, and carbon nanotubes evenly to obtain a mixture; S2. Spread the mixture on the upper and lower surfaces of the carbon fiber square cloth with surface active functional group modification treatment respectively, and dry and semi - cure it to obtain the carbon fiber square prepreg. The mass ratio of the carbon fiber square cloth with surface active functional group modification treatment to the mixture in the carbon fiber square prepreg is (60 - 64):(36 - 40); Step 2, cure the carbon fiber prepreg obtained in Step 1 at 40 - 50 °C for 36 - 48 h.

2. The carbon fiber composite material for manufacturing a special shoe tip according to claim 1, characterized in that: The carbon fiber prepreg in Step 1 contains 0° carbon fiber prepreg, and the preparation method of the 0° carbon fiber prepreg is as follows: S1. Perform surface active functional group modification treatment on the carbon fiber filaments; [[ID= S2. Thread the carbon fiber filaments modified with surface active functional groups between two yarn guiding plates. The carbon fiber filaments between the yarn guiding plates are evenly spaced along the 0° direction. Preheat and press the plasticizable resin film onto the upper and lower surfaces of the 0° carbon fiber filament layer treated with surface active functional groups between the two yarn guiding plates respectively, and then the 0° carbon fiber prepreg can be obtained. The addition amount of the 0° carbon fiber filaments in the 0° carbon fiber prepreg is 60-64 wt%. Or the carbon fiber prepreg in step one includes a 90° carbon fiber prepreg. The preparation method of the 90° carbon fiber prepreg is as follows: S1. Conduct surface active functional group modification treatment on the carbon fiber filaments. Meanwhile, accurately measure and mix the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes to obtain a mixture. Coat the mixture on the release paper and conduct semi-curing treatment to obtain a plasticizable resin film. S2. Thread the carbon fiber filaments modified with surface active functional groups between two yarn guiding plates. The carbon fiber filaments between the yarn guiding plates are evenly spaced along the 90° direction. Preheat and press the plasticizable resin film onto the upper and lower surfaces of the 90° carbon fiber filament layer treated with surface active functional groups between the two yarn guiding plates respectively, and then the 90° carbon fiber prepreg can be obtained. The addition amount of the 90° carbon fiber filaments in the 90° carbon fiber prepreg is 60-64 wt%.

3. A carbon fiber composite material for manufacturing special shoe tips according to claim 2, characterized in that: The thickness of the carbon fiber square pre-impregnated fabric is 0.2 - 0.8 mm; the gram weight of the carbon fiber square fabric in the carbon fiber square pre-impregnated fabric is 100 - 600 g / m 2 ; the specification of the carbon fiber in the carbon fiber square fabric is any one or a combination of 1K, 3K, 6K, 12K, and 24K; the specification of the carbon fiber filaments arranged at equal intervals along the 0° direction in the 0° carbon fiber pre-impregnated fabric is any one or a combination of 1K, 3K, 6K, 12K, and 24K; the specification of the carbon fiber filaments arranged at equal intervals along the 90° direction in the 90° carbon fiber pre-impregnated fabric is any one or a combination of 1K, 3K, 6K, 12K, and 24K.

4. A carbon fiber composite material for manufacturing special shoe tips according to claim 3, characterized in that: The carbon fiber yarns in the 0° carbon fiber prepreg, 90° carbon fiber prepreg, and carbon fiber square prepreg are surface active functional group modified carbon fiber yarns. The preparation method of the surface active functional group modified carbon fiber yarns is as follows: First, untwist the carbon fiber yarns, then place the untwisted carbon fiber yarns in hydrogen peroxide for ultrasonic modification treatment for 10-20 min, and finally dry and twist them to obtain the surface active functional group modified carbon fiber yarns. The surface active functional group modified carbon fiber yarns contain active hydroxyl groups and active carboxyl groups.

5. A carbon fiber composite material for manufacturing special shoe tips according to claim 3, characterized in that: The content of the carbon fiber square cloth in the carbon fiber square prepreg is 60-63 wt%, and the content of the carbon nanotubes is 0.70-0.75 wt%. The content of the carbon fiber filaments in the 0° carbon fiber prepreg and the 90° carbon fiber prepreg is 60-63 wt%, and the content of the carbon nanotubes is 0.70-0.75 wt%.

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