Carbon fiber composite material for manufacturing special toe cap and preparation method thereof

Abstract

The invention relates to the technical field of safe toe cap preparation, in particular to a carbon fiber composite material for manufacturing a special toe cap and a preparation method of the carbon fiber composite material. The invention relates to a carbon fiber composite material for manufacturing a special toe cap. The carbon fiber composite material is formed by hot pressing a plurality of carbon fiber prepreg cloths; the carbon fiber prepreg is prepared from the following raw materials in parts by weight: 60 to 64 parts of carbon fibers, 25 to 28 parts of matrix resin, 3 to 4 parts of low-shrinkage resin, 0.15 to 0.25 part of an initiator, 0.2 to 0.5 part of a cross-linking agent, 4 to 6 parts of styrene, 0.4 to 0.6 part of magnesium oxide, 0.3 to 0.4 part of a defoaming agent, 1 to 1.5 parts of a release agent and 0.6 to 0.8 part of carbon nanotubes. The carbon fibers at least comprise carbon fiber woven roving. The safety toe cap prepared from the carbon fiber composite material disclosed by the invention has good compressive strength, impact strength and antistatic property, and can meet the electrostatic protection requirement of the safety toe cap for the electronic 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 touching sharp objects in the construction environment and being hit by heavy objects falling from high altitudes on their toes. They are widely used in operation sites 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 made of steel, such as size 25 steel safety toe caps, size 40 steel safety toe caps, size 45 steel safety toe caps, size 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 the relatively heavy mass of safety shoes prepared with steel metal toe caps, which affects the mobility and flexibility of workers. In addition, 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 again, and 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, and the fiberglass prepreg mesh sheet is formed into a toe cap preform by the hand lay-up molding method, and then 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, which requires that the safety toe cap also needs to have good antistatic performance. 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 fiberglass safety toe caps 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 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: 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 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.

[0008] The present invention contains several carbon fiber square prepregs and carbon nanotubes with hydroxylation or amination modification treatment, effectively ensuring the compressive strength and impact strength of the prepared safety shoe tips, and can form a conductive network skeleton. Cooperating 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.

[0009] In the present invention, the carbon nanotubes are subjected to hydroxylation or amination modification treatment, which improves the compatibility between the carbon nanotubes and the matrix resin, enables the carbon nanotubes to be uniformly 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, can effectively eliminate the harm of human static electricity, and better meets the electrostatic protection requirements of the electronics industry.

[0010] 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 applicable to 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.

[0011] 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, avoid problems such as breakdown and damage of electronic components caused by static electricity, and ensure the quality of electronic products.

[0012] 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.

[0013] 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, avoid dust absorption on the toe surface, reduce safety hazards at work, and ensure the safety of workers and sites.

[0014] 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.

[0015] Preferably, the carbon fiber is a carbon fiber woven fabric or the carbon fiber is a carbon fiber woven fabric combined with at least one of 0° carbon fiber and 90° carbon fiber; 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 toe cap is formed by hot pressing a plurality of carbon fiber lattice prepregs; When the carbon fiber is carbon fiber lattice cloth and 0° carbon fiber, the carbon fiber prepreg is carbon fiber lattice prepreg and 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 prepreg and a plurality of 0° carbon fiber prepreg; 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 prepreg and a plurality of 90° carbon fiber prepreg; 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 toe cap is formed by hot pressing a plurality of carbon fiber lattice prepreg, a plurality of 0° carbon fiber prepreg and a plurality of 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.

[0016] Preferably, the carbon fiber lattice prepreg has a thickness of 0.2-0.8 mm.

[0017] Preferably, the weight of the carbon fiber lattice prepreg is 100-600 g / m 2 ; The specification of the carbon fiber in the carbon fiber woven cloth is any one of 1K, 3K, 6K, 12K, 24K or a combination of multiple ones.

[0018] Preferably, the carbon fiber filaments arranged at uniform intervals in the 0° carbon fiber prepreg have a specification of any one or more combinations of 1K, 3K, 6K, 12K, and 24K.

[0019] More preferably, the carbon fiber filaments arranged at uniform intervals in the 0° carbon fiber prepreg have a specification of 12K.

[0020] Preferably, the carbon fiber filaments arranged at uniform intervals in the 90° carbon fiber prepreg have a specification of any one or more combinations of 1K, 3K, 6K, 12K, and 24K.

[0021] More preferably, the carbon fiber filaments arranged at uniform intervals in the 90° carbon fiber prepreg have a specification of 12K.

[0022] By adopting the above technical solution, the prepared carbon fiber safety toe caps all meet the protection standard of EN 22568, and the production process is relatively simple, which can reduce the production cost.

[0023] 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.

[0024] By adopting the above technical solution, the compatibility between the carbon fiber yarns and the matrix resin is improved, the overall compressive strength and impact strength of the safety toe caps can be improved, and at the same time, it is also beneficial to improve the overall antistatic performance.

[0025] Preferably, the content of the 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 content of carbon fiber filaments in the 0° carbon fiber prepreg and the 90° carbon fiber prepreg is 60 - 63 wt%, and the content of carbon nanotubes is 0.70 - 0.75 wt%.

[0026] By adopting the above technical solution, the 0° carbon fiber prepreg, 90° carbon fiber prepreg, and carbon fiber square 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 that meets the protection standard of EN 22568 can be prepared.

[0027] The preparation method of a carbon fiber composite material for manufacturing special shoe tips provided by the present invention is realized through the following technical solutions: A preparation method of a carbon fiber composite material for manufacturing special shoe tips includes the following steps: Step 1, prepare carbon fiber prepreg; Step 2, cure the carbon fiber prepreg in Step 1 at 40 - 50 °C for 36 - 48 h; Step 3, cut the cured carbon fiber prepreg 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 layering method, demold and trim after hot pressing to obtain a finished carbon fiber safety shoe tip.

[0028] 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 realize batch manufacturing, and the production cost of safety shoe tips is reduced.

[0029] 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: S1. Modify the surface active functional groups of the carbon fiber square cloth; at the same time, mix accurately metered matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, 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. Preheat and 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, and 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 (60 - 64):(36 - 40), then the carbon fiber square prepreg can be prepared.

[0030] 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: S1. Modify the surface active functional groups of the carbon fiber square cloth; at the same time, mix accurately metered matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, carbon nanotubes evenly to obtain a mixture; S2. Scrapingly coat 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 to obtain the carbon fiber square prepreg, and 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).

[0031] 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 carbon fiber filaments; at the same time, accurately measure matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes, mix them evenly to obtain a mixture, and coat the mixture on a release paper for semi-curing treatment to obtain a plastic resin film; S2. Thread the surface active functional group-modified carbon fiber filaments between two yarn guiding plates, and 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, 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 60-64wt%.

[0032] 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: S1. Perform surface active functional group modification on carbon fiber filaments; At the same time, accurately measure matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes, mix them evenly to obtain a mixture, and coat the mixture on a release paper for semi-curing treatment to obtain a plastic resin film; S2. Thread the surface active functional group-modified carbon fiber filaments between two yarn guiding plates, and 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 90° carbon fiber filament layer with surface active functional group modification 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%.

[0033] In summary, the present application has the following advantages: 1. The safety toe cap prepared from 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.

[0034] 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.

[0035] 3. The thickness of the carbon fiber safety toe cap in the present invention can be customized according to customer requirements. On the premise of meeting the protection standard of EN22568, a safety toe cap with a wall thickness of 6mm and an ultra-light series can be prepared.

[0036] 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

[0037] Figure 1 It is a physical display diagram of the fiberglass safety toe cap prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0038] 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 conjunction 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 to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law. EXAMPLE

[0039] A carbon fiber composite material for manufacturing special toe caps is formed by hot pressing several 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 resistance of the carbon fiber safety toe cap can be adjusted. The carbon fiber safety toe cap meets the protection standards of European standard EN 22568, Canadian standard CSA, and American standard ASTM.

[0040] The carbon fiber prepreg is 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.

[0041] The low shrinkage resin is specifically polycaprolactone NPG200.

[0042] 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 composed of at least one of titanium tetraisopropoxide, dibutyltin dilaurate, and stannous octoate.

[0043] The mold release agent is at least one of metal stearates, molybdenum disulfide, talc powder, and fumed silica.

[0044] The crosslinking agent in the formula of the carbon fiber prepreg contains at least two double bonds, and can be selected from at least one of dipropylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate.

[0045] 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, and so on.

[0046] The carbon fiber in the carbon fiber prepreg formula includes at least carbon fiber square cloth.

[0047] Preferably, the carbon fiber in the carbon fiber prepreg formula is carbon fiber square cloth or composed of carbon fiber square cloth combined with at least one of 0° carbon fiber filaments and 90° carbon fiber filaments.

[0048] The compatibility between the carbon fiber and the prepreg resin matrix in the carbon fiber prepreg formula is poor, so 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.

[0049] 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.

[0050] Method 1: 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. The ultrasonic modification time is related to the selected carbon fiber yarn specification. 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, which contains active hydroxyl groups and active carboxyl groups.

[0051] 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 carry out 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.

[0052] Due to the different forms of carbon fibers 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.

[0053] Specifically, when the carbon fiber is a carbon fiber square cloth, the carbon fiber prepreg is a carbon fiber square prepreg. The carbon fiber composite material used to manufacture special shoe tips is formed by hot pressing several carbon fiber square prepregs. The content of the 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.

[0054] 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.

[0055] 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 grammage of the carbon fiber square cloth in 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.

[0056] Specifically, when the carbon fiber is a carbon fiber square cloth and 0° carbon fiber filaments, the carbon fiber prepreg is a carbon fiber square prepreg and 0° carbon fiber prepreg. The carbon fiber composite material used to manufacture special shoe tips is formed by hot pressing several carbon fiber square prepregs and several 0° carbon fiber prepregs. The specification of the carbon fiber filaments evenly spaced along the 0° direction in the 0° carbon fiber prepreg is any one or a combination of 1K, 3K, 6K, 12K, and 24K. Preferably, the specification of the carbon fiber filaments evenly spaced along the 0° direction in the 0° carbon fiber prepreg is 12K. The content of the carbon fiber filaments in the 0° carbon fiber prepreg is 60 - 63 wt%, and the content of carbon nanotubes is 0.70 - 0.75 wt%.

[0057] 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 used to manufacture the special shoe tip is formed by hot pressing a number of carbon fiber square prepregs and a number of 90° carbon fiber prepregs. The specifications of the carbon fiber filaments arranged at uniform intervals in the 90° direction in the 90° carbon fiber prepreg are any one or more combinations of 1K, 3K, 6K, 12K, and 24K. Preferably, the specifications of the carbon fiber filaments arranged at uniform intervals in the 90° direction in the 90° carbon fiber prepreg are 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%.

[0058] 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 used to manufacture the special shoe tip 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.

[0059] 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 the special shoe tip are also different, which will affect the comprehensive performance of the final carbon fiber composite material.

[0060] According to the different carbon fiber specifications limited 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 tip. Meeting the protection standard of EN 22568 can meet the personalized customization requirements.

[0061] The carbon nanotubes are at least one of hydroxyl-modified carbon nanotubes and amino-modified carbon nanotubes. The surface hydroxylation and / or amino-modification 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 to form 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, effectively eliminating the harm of human static electricity and better meeting the electrostatic protection requirements of the electronics industry.

[0062] The addition amount of carbon nanotubes will affect the overall antistatic performance. When the carbon nanotubes are less than 0.6 wt%, the decline in the overall electrical conductivity and antistatic performance is significant, making the overall antistatic performance fail to meet the standard. Although when the carbon nanotubes are less than 0.8 wt%, the overall antistatic performance and mechanical strength can be improved, it will lead to an increase in the overall production cost, which is not conducive to mass production and manufacturing.

[0063] A preparation method of a carbon fiber composite material for manufacturing a special shoe tip includes the following steps: Step 1, prepare a carbon fiber prepreg; Step 2, cure the carbon fiber prepreg in Step 1 at 40 - 50 °C for 36 - 48 h; 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 tip by the manual lay-up method, and after hot pressing and molding, demolding and trimming are performed to obtain the finished carbon fiber safety shoe tip.

[0064] 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: 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. The mixture is coated on the release paper and semi-cured to obtain a plastic resin film; S2. Preheat and 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 (60 - 64):(36 - 40), and then the carbon fiber square prepreg is obtained.

[0065] 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: 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; S2. Scrapingly coat 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 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).

[0066] Preferably, the carbon fiber prepreg in Step 1 includes a 0° carbon fiber prepreg, and the preparation method of the 0° carbon fiber prepreg is as follows: S1. Modify the surface active functional groups of carbon fiber filaments; Meanwhile, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes, mix them evenly to obtain a mixture, coat the mixture on a release paper and perform semi-curing treatment to obtain a plastic resin film; S2. Thread the carbon fiber filaments with surface active functional group modification between two yarn guide plates. The carbon fiber filaments between the yarn guide 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 guide plates respectively, and then a 0° carbon fiber prepreg can be obtained. The addition amount of 0° carbon fiber filaments in the 0° carbon fiber prepreg is 60 - 64 wt%.

[0067] Preferably, 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. Modify the surface active functional groups of carbon fiber filaments; Meanwhile, accurately measure the matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoaming agent, mold release agent, and carbon nanotubes, mix them evenly to obtain a mixture, coat the mixture on a release paper and perform semi-curing treatment to obtain a plastic resin film; S2. Thread the carbon fiber filaments with surface active functional group modification between two yarn guide plates. The carbon fiber filaments between the yarn guide plates are evenly spaced along the 90° direction. Preheat and press the plastic resin film on the upper and lower surfaces of the 90° carbon fiber filament layer with surface active functional group modification between the two yarn guide plates respectively, and then a 90° carbon fiber prepreg can be obtained. The addition amount of 90° carbon fiber filaments in the 90° carbon fiber prepreg is 60 - 64 wt%.

[0068] Example 1: The carbon fiber composite material used to manufacture 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, 0.42 mm in thickness), 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), 0.714 parts of carbon nanotube TNGMC2.

[0069] 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 and a gram weight of 400 g / m 2 , 0.42 mm in thickness.

[0070] Epoxy-modified acrylic resin WDS-6225, brand LQ, viscosity (at 60 °C) 600 - 1200.

[0071] Carbon nanotube TNGMC2, Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, OD: 8 - 15 nm, length 10 - 50 μm, -COOH content 1.28 wt%.

[0072] A preparation method of a carbon fiber composite material for manufacturing special shoe tips, comprising the following steps: Step 1, preparing a carbon fiber square prepreg: Preparing a finished carbon fiber square cloth: Cut the carbon fiber square cloth (12k carbon fiber reinforced plain cloth, gram weight 400 g / m 2 , 0.42 mm in thickness) into 300 m * 300 mm, place it in a low-temperature plasma surface treatment instrument NE PE-10, adjust the temperature to 4 ± 0.5 °C, the frequency of the plasma emitter is 40 KHz, the power is 600 W, use air as the low-temperature plasma gas source, perform 60 s of 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 40 KHz, the power is 600 W, use air as the low-temperature plasma gas source, perform 60 s of low-temperature plasma treatment on the 12k carbon fiber reinforced plain cloth, and then the finished carbon fiber square cloth can be obtained; 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 defoam for 45 min. After defoaming 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; Evenly scrape 10.8 g of the impregnating resin onto one surface of the finished carbon fiber square cloth, then evenly scrape 10.8 g of the impregnating resin onto the other surface of the finished carbon fiber square cloth, and then laminate release paper on both sides to obtain a carbon fiber square prepreg; Step 2, cure the carbon fiber square prepreg in Step 1 at 40 °C for 36 h; Step 3, cut the carbon fiber square prepreg cured 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 shoe tip by the manual layering method, and perform hot pressing and forming 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 a finished carbon fiber safety shoe tip.

[0073] The difference between Example 2 and Example 1 is that the preparation method of the carbon fiber composite material used to manufacture the special shoe tip is as follows. Step 1, prepare the carbon fiber square prepreg: Prepare the finished carbon fiber square cloth: Cut the carbon fiber square cloth (12k carbon fiber reinforced plain cloth, gram weight 400 g / m 2 , thickness 0.42 mm) into 300 m * 300 mm, place it in a low-temperature plasma surface treatment instrument NE PE-10, adjust the temperature to 4 ± 0.5 °C, the frequency of the plasma emitter is 40 KHz, and the power is 600 W. Use air as the low-temperature plasma gas source to perform 60 s of 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 again. Adjust the temperature to 4 ± 0.5 °C, the frequency of the plasma emitter is 40 KHz, and the power is 600 W. Use air as the low-temperature plasma gas source to perform 60 s of low-temperature plasma treatment on the 12k carbon fiber reinforced plain cloth to obtain the finished carbon fiber square cloth; 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; Evenly scrape 10.8 g of the impregnating resin onto the surface of a 300 m * 300 mm release paper, and pre-cure it at 80 °C for 90 s to obtain an impregnating resin film sheet for standby; Preheat and press two impregnating resin film sheets onto the upper and lower surfaces of a finished carbon fiber square cloth respectively, and pre-cure it at 80 °C for 30 s to obtain a carbon fiber square prepreg for standby; Step 2, place the carbon fiber square prepreg in Step 1 at 40 °C for curing for 36 h; Step 3, cut the carbon fiber square prepreg cured 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 shoe tip by the manual layering method, and perform hot pressing forming 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 a finished carbon fiber safety shoe tip.

[0074] The difference between Example 3 and Example 2 is that in the preparation of the carbon fiber square prepreg in Step 1, evenly scrape 12 g of the impregnating resin onto the surface of a 300 m * 300 mm release paper, and pre-cure it at 80 °C for 90 s to obtain an impregnating resin film sheet for standby; Preheat and press two plastic resin films onto the upper and lower surfaces of a finished carbon fiber square cloth respectively, and pre-cure it at 80 °C for 30 s to obtain a carbon fiber square prepreg for standby.

[0075] The difference between Example 4 and Example 2 is that in the preparation of the carbon fiber square prepreg in Step 1, evenly scrape 10.1 g of the impregnating resin onto the surface of a 300 m * 300 mm release paper, and pre-cure it at 80 °C for 90 s to obtain an impregnating resin film sheet for standby; Preheat and press two plastic resin films onto the upper and lower surfaces of a finished carbon fiber square cloth respectively, and pre-cure it at 80 °C for 30 s to obtain a carbon fiber square prepreg for standby.

[0076] Example 5 is different from Example 2 in that: in Step 3, the carbon fiber square pre-impregnated fabric after the aging treatment in Step 2 is cut into a finished carbon fiber pre-impregnated fabric that fits the shape of the forming mold. The finished carbon fiber pre-impregnated fabric is stacked into a preformed toe cap by the manual lay-up method, with a thickness of 6.0 mm. The hot pressing forming treatment is carried out 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, demolding, cutting and trimming, and polishing the edges, the finished carbon fiber safety toe cap is obtained. The thickness of the preformed toe cap in Example 2 is 8.0 mm.

[0077] The difference between Comparative Example 1 and Example 1 lies in: in the preparation of the carbon fiber square pre-impregnated fabric in Step 1, 9.4 g of impregnating resin was evenly scraped onto the surface of a 300 m * 300 mm release paper, and pre-cured at 80 °C for 90 s to obtain an impregnated resin film sheet for standby; two pieces of plastic resin films were respectively pre-heat pressed onto the upper and lower surfaces of the finished carbon fiber square fabric, and pre-cured at 80 °C for 30 s to obtain the carbon fiber square pre-impregnated fabric for standby.

[0078] The difference between Comparative Example 2 and Example 1 lies in: in the preparation of the carbon fiber square pre-impregnated fabric in Step 1, 12.5 g of impregnating resin was evenly scraped onto the surface of a 300 m * 300 mm release paper, and pre-cured at 80 °C for 90 s to obtain an impregnated resin film sheet for standby; two pieces of plastic resin films were respectively pre-heat pressed onto the upper and lower surfaces of the finished carbon fiber square fabric, and pre-cured at 80 °C for 30 s to obtain the carbon fiber square pre-impregnated fabric for standby.

[0079] 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 obtained by hot pressing and forming several glass fiber square pre-impregnated fabrics. The glass fiber square pre-impregnated fabric 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 titanium tetraisopropoxide, 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.

[0080] A glass fiber composite material for manufacturing a special toe cap, comprising the following steps: Step 1, preparing a glass fiber square pre-impregnated fabric: Preparation of impregnating resin: 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 were placed in a reaction kettle, and stirred and degassed under nitrogen protection for 45 min. After degassing, 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement were added, and the mixture was evenly mixed to obtain the impregnating resin; 10.8 g of the impregnating resin was evenly scraped onto one surface of an EWR400 fiberglass grid cloth with a specification of 300*300 mm, and then 10.8 g of the impregnating resin was evenly scraped onto the other surface of the EWR400 fiberglass grid cloth. It was pre-cured at 80°C for 120 s, and release paper was laminated on both sides to obtain a pre-impregnated fiberglass square cloth; Step 2: The pre-impregnated fiberglass square cloth in Step 1 was placed at 40°C for 36 h of curing; 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 fit the shape of the forming mold. The finished carbon fiber pre-impregnated cloth was stacked into a pre-shaped toe cap by the manual lamination method, and hot pressing forming treatment was carried out 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 were carried out to obtain the finished carbon fiber safety toe cap.

[0081] The difference between Comparative Example 4 and Example 1 is that: carbon nanotubes are not added to the carbon fiber square pre-impregnated cloth. Specifically, the carbon fiber square pre-impregnated cloth 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 400 g / m 2 , thickness 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 defoamer - BYK051N defoamer, 1.116 parts of zinc stearate, and 0.714 parts of carbon black (Mitsubishi carbon black #3400B).

[0082] Performance detection test: The sizes of the carbon fiber safety toe cap and the fiberglass safety shoe were tested as size 8#.

[0083] 1. Residual height (mm) after 200J impact: Measured in accordance with the requirements of European standard EN 22568-2019.

[0084] 2. Residual height after 15 kN impact (mm): Measured in accordance with the requirements of European Standard EN 22568-2019.

[0085] 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, 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, the carbon fiber safety toe cap does not have antistatic performance, recorded as unqualified NG.

[0086] 4. Puncture resistance: 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.

[0087] 5. Abrasion resistance: Use a Martindale abrasion tester, with 180# sandpaper as the abrasive, 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.

[0088] Table 1: Tolerance performance parameter table of carbon fiber toe caps in Examples 1-5 and Comparative Examples 1-4

[0089] Table 2: Mechanical parameter table of carbon fiber toe caps in Examples 1-5 and Comparative Examples 1-4

[0090] Combining Examples 2-4 and Comparative Examples 1-2 and Tables 1-2, it can be seen that when the content of carbon fiber square cloth in the carbon fiber square pre-preg is controlled at 60-64 wt%, it can ensure that the carbon fiber safety toe cap has good compressive strength and impact strength. When the content of carbon fiber square cloth in the carbon fiber square pre-preg is less than 60 wt%, the internal clearance height of the carbon fiber safety toe cap after 15 kN compression is lower 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.

[0091] Combining Example 2 and Comparative Example 3 and Tables 1-2, it can be seen that the addition of carbon nanotubes can improve the antistatic performance, abrasion resistance and impact strength of the carbon fiber safety toe cap.

[0092] Combined with Example 2 and Comparative Examples 3-4 and in conjunction with 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 toe than carbon black. The reason is that the carbon nanotubes with a high aspect ratio can effectively conduct the carbon fiber square cloth in the carbon fiber toe matrix to form a three-dimensional network-shaped conductive skeleton. That is, by adding carbon nanotubes to the carbon fiber square prepreg formula, the antistatic performance, wear resistance and impact strength of the carbon fiber safety toe can be better improved.

[0093] Combined with Examples 1-4 and Comparative Examples 1-2 and in conjunction with Tables 1-2, it can be seen that the carbon fiber safety toe prepared by using the prepreg 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.

[0094] The difference between Example 6 and Example 2 is that the carbon fiber composite material used to manufacture the special toe is obtained by hot pressing a plurality of carbon fiber square prepregs and 0° carbon fiber prepregs. The carbon fiber square prepreg used in Example 6 is the same as the carbon fiber square prepreg used in Example 2.

[0095] The 0° carbon fiber prepreg is made of 62.5 parts of Toho HTS40 F13 12K carbon fiber yarn, 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 titanium tetraisopropoxide (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.

[0096] A carbon fiber composite material for manufacturing a special toe includes the following steps: 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; At the same time, prepare the 0° carbon fiber prepreg: 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.

[0097] 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 degas 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. 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. Step 2: 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 the 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 guiding plates, and pre-cure at 80°C for 30 s to obtain the 0° carbon fiber prepreg with a thickness of 0.30 ± 0.02 mm. Step 2: Cure the carbon fiber prepreg in Step 1 at 40°C for 36 h. Step 3: Cut the carbon fiber square pre-impregnated fabric after the aging treatment in Step 2 to obtain a finished carbon fiber pre-impregnated fabric that fits the shape of the forming mold. Stack the finished carbon fiber pre-impregnated fabric into a preformed shoe toe by the manual lamination method. The stacking method is as follows: The carbon fiber square pre-impregnated fabric is marked as A, and the 0° carbon fiber pre-impregnated fabric is marked 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 forming treatment using a mold. Hot pressing parameters: Hot press for 10 minutes at 145 °C and a pressure of 50 kg. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety shoe toe.

[0098] The difference between Example 7 and Example 2 is that the carbon fiber composite material used to manufacture the special shoe toe is obtained by hot pressing and forming several carbon fiber square pre-impregnated fabrics and 90° carbon fiber pre-impregnated fabrics. The carbon fiber square pre-impregnated fabric used in Example 7 is the same as the carbon fiber square pre-impregnated fabric used in Example 2. The 90° carbon fiber pre-impregnated fabric 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 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.

[0099] A carbon fiber composite material for manufacturing a special shoe toe includes the following steps: Step 1: The preparation method of the carbon fiber square pre-impregnated fabric is the same as that of the carbon fiber square pre-impregnated fabric in Example 2, that is, the carbon fiber square pre-impregnated fabric used in Example 6 is the same as the carbon fiber square pre-impregnated fabric used in Example 2; At the same time, prepare 90° carbon fiber pre-impregnated fabric: 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, put it into an 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 groups -OH and active carboxyl groups -COOH on its surface.

[0100] 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, 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 a release paper of 900 mm * 900 mm, and pre-cure it at 80°C for 90 s to obtain a prepreg resin film for standby. 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 arranged at intervals along the 90° direction. The amount of the 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 treatment between the two yarn guides, and pre-cure it at 80°C for 30 s to obtain a 90° carbon fiber prepreg with a thickness of 0.30 ± 0.02 mm. Step 2: Cure the carbon fiber prepreg in Step 1 at 40°C for 36 h. Step 3: Cut the carbon fiber square pre-impregnated fabric after the aging treatment in Step 2 into a finished carbon fiber pre-impregnated fabric that fits the shape of the forming mold. Stack the finished carbon fiber pre-impregnated fabric into a preformed shoe tip by the manual lay-up method. The stacking method is as follows: the carbon fiber square pre-impregnated fabric is marked as A, and the 90° carbon fiber pre-impregnated fabric is marked as C. The specific structure of the prefabricated sheet is as follows: AAA / C / AAA / C / AAAA / C / AAA / C / AAA. Then, perform hot pressing forming treatment using a mold. The hot pressing parameters are: hot press for 10 minutes at 145°C and a pressure of 50 kg. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety shoe tip.

[0101] The difference between Example 9 and Example 2 is that the carbon fiber composite material used to manufacture the special shoe tip is obtained by hot pressing and forming several carbon fiber square pre-impregnated fabrics, 0° carbon fiber pre-impregnated fabric heat, and 90° carbon fiber pre-impregnated fabric. The carbon fiber square pre-impregnated fabric used in Example 9 is the same as the carbon fiber square pre-impregnated fabric used in Example 2.

[0102] The 0° carbon fiber pre-impregnated fabric is made of 62.5 parts of Toho HTS40 F13 12K carbon fiber yarn, 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 cross-linking 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.

[0103] 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.

[0104] A carbon fiber composite material for manufacturing special shoe tips includes the following steps: 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; At the same time, prepare 0° carbon fiber prepreg: 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, and 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.

[0105] 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 defoam for 45 minutes. 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 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; In the second step, thread the Toray HTS40 F13 12K carbon fiber yarn modified with surface active functional groups through between two yarn guides. The length of the yarn guides is 900 mm, the distance between the two yarn guides is 900 mm, and the carbon fiber filaments between the yarn guides are evenly spaced along the 0° direction. The amount of Toray 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 modified with surface active functional groups between the two yarn guides, 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; Meanwhile, prepare a 90° carbon fiber prepreg. The difference in the preparation method between the 90° carbon fiber prepreg and the 0° carbon fiber prepreg is that in the second step, thread the Toray HTS40 F13 12K carbon fiber yarn modified with surface active functional groups through between two yarn guides. The length of the yarn guides is 900 mm, the distance between the two yarn guides is 900 mm, and the carbon fiber filaments between the yarn guides are evenly spaced along the 90° direction. The amount of Toray 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 90° carbon fiber filament layer modified with surface active functional groups between the two yarn guides, 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; In the second step, cure the carbon fiber prepreg in step one at 40 °C for 36 h; Step 3: Cut the carbon fiber square prepreg after the aging 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 lamination method. The stacking method is as follows: Mark the carbon fiber square prepreg as A, the 0° carbon fiber prepreg as B, and the 90° carbon fiber prepreg as C. The specific structure of the prefabricated sheet is as follows: AAA / C / AAA / B / AAAA / B / AAA / C / AAA. Then, perform hot pressing and forming treatment using a mold. The hot pressing parameters are: hot press for 10 minutes at 145°C and a pressure of 50 kg. After cooling to room temperature, demold, cut and trim the edges, and polish the edges to obtain the finished carbon fiber safety toe cap.

[0106] The difference between Example 9 and Example 2 lies in that the preparation method of the carbon fiber square prepreg in Step 1 is as follows: First step: Preparation of surface active functional group modified carbon fiber yarn: 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 minutes. The frequency of the ultrasonic emitter is 40 kHz and the power is 600 W. Then, put it into an 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.

[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, and 0.714 parts of carbon nanotube TNGMC2 into a reaction kettle, stir and defoam under nitrogen protection for 45 minutes. After defoaming 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 60 g of the impregnating resin evenly on a release paper of 1000 mm * 500 mm, and pre-cure it at 80°C for 90 s to obtain a prepreg resin film for standby; Second step: Use the surface active functional group modified T400HB-6000 carbon fiber yarn as the warp and weft, with a warp and weft density of 5 * 5 roots each, and weave it flat to obtain a surface active functional group modified carbon fiber square cloth with a gram weight of 400 g / m 2 , a thickness of 0.42 mm, a width of 500 mm, and a cut length of 1000 mm; Step 3: Press two pieces of impregnated resin film with the specification of 1000mm * 500mm onto 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 30s to obtain the carbon fiber square pre-impregnated cloth. The remaining steps are the same.

[0108] The difference between Example 10 and Example 9 lies in: Step 1, the preparation method of the carbon fiber square pre-impregnated cloth is as follows: First step, the specific preparation of the electro-polymerization composite modified carbon fiber yarn is as follows. First, clean the Toray T400HB-6000 carbon fiber yarn successively with acetone and deionized water; then, the cleaned T400HB-6000 carbon fiber yarn is electro-polymerized 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 liquid level contains 0.2M / L of aniline monomer and 0.05 / L of aniline monomer, the cyclic voltage is 1.4V, the electro-polymerization time is 10min, take it out, rinse it three times with deionized water, and dry it to obtain the electro-polymerization composite modified carbon fiber yarn T400HB-6000.

[0109] Meanwhile, prepare the impregnated 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 degas under nitrogen protection for 45min. 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 impregnated resin. Spread 120g of the impregnated resin evenly on the release paper with the size of 1000mm * 1000mm, and pre-cure at 80°C for 90s to obtain the pre-impregnated cloth resin film for standby; Second step, use the electro-polymerization composite modified carbon fiber yarn T400HB-6000 as the warp and weft, the warp and weft density is 5 * 5, and weave it flatly to obtain the electro-polymerization composite modified carbon fiber square cloth with a gram weight of 400g / m 2 , a thickness of 0.42mm, a width of 1000mm, and a cut length of 1000mm; Step 3: Press two pieces of impregnated resin film with the specification of 1000mm * 1000mm onto 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 30s to obtain the carbon fiber square pre-impregnated cloth. The remaining steps are the same.

[0110] Example 11 is different from Example 9 in that: in Step 3, the carbon fiber square prepreg after the ripening treatment in Step 2 is cut into a finished carbon fiber prepreg that fits the shape of the forming mold, and the finished carbon fiber prepreg is stacked into a preformed toe cap by the manual lamination 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: AA / C / AA / B / AAA / B / AA / C / AA. It is subjected to hot pressing and forming 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, it is demolded, cut and trimmed, and the edges are polished to obtain a finished carbon fiber safety toe cap with a thickness of 6.0 mm.

[0111] Comparative Example 4 is different from Example 2 in that: in Step 1, a carbon fiber square prepreg is prepared: The first step is to prepare an impregnating resin: 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 are placed in a reaction kettle, and stirred and degassed under nitrogen protection for 45 min. After degassing is completed, 0.112 parts of initiator BPO and 0.089 parts of tetraisopropyl titanate with accurate measurement are added and mixed evenly to obtain the impregnating resin; The second step is to evenly scrape 10.8 g of the impregnating resin on the surface of a 300 m * 300 mm release paper, and pre-cure it at 80 °C for 90 s to obtain an impregnating resin film sheet for standby; The third step is to pre-heat 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 m * 300 mm), and pre-cure it at 80 °C for 30 s to obtain a carbon fiber square prepreg.

[0112] Table 3: Tolerance performance parameter table of carbon fiber toe caps in Example 2 and Examples 5-11 and Comparative Example 4

[0113] Table 4: Mechanical parameter table of carbon fiber toe caps in Example 2 and Examples 5-11 and Comparative Example 4

[0114] Combined with Example 2, Examples 5 - 11 and Comparative Example 4 and in conjunction with Table 3 - 4, it can be seen that the carbon fiber composite materials used to manufacture special shoe tips, whether formed by hot - pressing several carbon fiber square pre - impregnated fabrics or the carbon fiber shoe tips (with a thickness of 6.0 - 8.0 mm) prepared by combining several carbon fiber square pre - impregnated fabrics with at least one of 0° carbon fiber pre - impregnated fabric and 90° carbon fiber pre - impregnated fabric, all meet the protection standards of European standard EN22568, Canadian standard CSA, and American standard ASTM.

[0115] Combined with Example 2 and Comparative Example 4 and in conjunction with Table 3 - 4, it can be seen that without surface modification treatment of the carbon fiber square fabric in the carbon fiber square pre - impregnated fabric, the compatibility between the carbon fiber square fabric and the impregnating resin is affected, resulting in a significant decrease in both the compressive strength and impact resistance of the prepared carbon fiber shoe tip.

[0116] Combined with Example 2, Examples 9 - 10 and in conjunction with Table 3 - 4, it can be seen that the carbon fiber shoe tips prepared using the carbon fiber square pre - impregnated fabrics in Example 2 and 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 shoe tip prepared with the carbon fiber square pre - impregnated fabric in Example 9 is better than that of the carbon fiber shoe tip prepared with the carbon fiber square pre - impregnated fabric in Example 2.

[0117] Combined with Example 5 and Example 11 and in conjunction with Table 3 - 4, it can be seen that the carbon fiber shoe tips prepared using the carbon fiber square pre - impregnated fabrics in Example 5 and 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 shoe tip prepared with the carbon fiber square pre - impregnated fabric in Example 11 is better than that of the carbon fiber shoe tip prepared with the carbon fiber square pre - impregnated fabric in Example 5.

[0118] Combined with Example 5 and Examples 9 - 10 and in conjunction with Table 3 - 4, it can be seen that the impact resistance of the carbon fiber shoe tips prepared with the carbon fiber square pre - impregnated fabrics in Examples 10 and 11 is better than that of the carbon fiber shoe tip prepared with the carbon fiber square pre - impregnated fabric in Example 5. That is, the surface modification treatment method for the carbon fiber square fabric in Examples 9 - 10 is relatively better than the surface modification treatment method for the carbon fiber square fabric in Example 2. However, the cost of the surface modification treatment method for the carbon fiber square fabric in Example 9 is relatively higher.

[0119] In summary, the safety shoe tips prepared using the carbon fiber composite materials in the present invention have good compressive strength, impact resistance and also have good electrical conductivity, which can meet the electrostatic protection requirements of the electronics industry.

Claims

1. A carbon fiber composite material for manufacturing special toe caps, characterized in that: The carbon fiber composite material used for manufacturing special shoe heads is formed by hot pressing of a plurality of carbon fiber prepregs; the carbon fiber prepregs are made of the following raw materials in parts by weight: 60-64 parts of carbon fibers, 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 cross-linking 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, and 0.6-0.8 parts of carbon nanotubes; the cross-linking agent contains at least two double bonds; the matrix resin includes at least vinyl resin; the carbon fibers include at least carbon fiber lattice 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.

2. The carbon fiber composite material for manufacturing special toe cap according to claim 1, characterized in that: The carbon fiber is a carbon fiber woven fabric or the carbon fiber is a carbon fiber woven fabric combined with at least one of 0° carbon fiber filaments and 90° carbon fiber filaments; 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 toe cap is formed by hot pressing a plurality of carbon fiber lattice prepregs; When the carbon fiber is a carbon fiber lattice cloth and a 0° carbon fiber filament, the carbon fiber prepreg is a carbon fiber lattice prepreg and a 0° carbon fiber prepreg, and the carbon fiber composite material for manufacturing a special toe cap is formed by hot pressing a plurality of carbon fiber lattice prepregs and a plurality of 0° carbon fiber prepregs; When the carbon fiber is a carbon fiber lattice cloth and a 90° carbon fiber filament, the carbon fiber prepreg is a carbon fiber lattice prepreg and a 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; When the carbon fiber is carbon fiber lattice cloth, 0° carbon fiber filament and 90° carbon fiber filament, 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 toe cap is formed by hot pressing a plurality of carbon fiber lattice prepreg, a plurality of 0° carbon fiber prepreg and a plurality of 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.

3. The carbon fiber composite material for manufacturing special toe cap according to claim 2, characterized in that: The thickness of the carbon fiber lattice prepreg is 0.2-0.8 mm; the gram weight of the carbon fiber lattice prepreg is 100-600 g / m 2 ; The specification of the carbon fiber in the carbon fiber lattice cloth is any one or a combination of 1K, 3K, 6K, 12K, and 24K; the specification of the carbon fiber filaments evenly spaced along the 0° direction in the 0° carbon fiber prepreg cloth is any one or a combination of 1K, 3K, 6K, 12K, and 24K; the specification of the carbon fiber filaments evenly spaced along the 90° direction in the 90° carbon fiber prepreg cloth is any one or a combination of 1K, 3K, 6K, 12K, and 24K.

4. The carbon fiber composite material for manufacturing special toe cap according to claim 3, characterized in that: The carbon fiber yarn in the 0° carbon fiber prepreg, 90° carbon fiber prepreg, and carbon fiber lattice prepreg is a surface active functional group modified carbon fiber yarn. The preparation method of the surface active functional group modified carbon fiber yarn is as follows: firstly, the carbon fiber yarn is untwisted, and then the untwisted carbon fiber yarn is placed in hydrogen peroxide for ultrasonic modification for 10-20 minutes, and finally, the surface active functional group modified carbon fiber yarn is dried and twisted to obtain the surface active functional group modified carbon fiber yarn, and the surface active functional group modified carbon fiber yarn contains active hydroxyl groups and active carboxyl groups.

5. The carbon fiber composite material for manufacturing special toe cap according to claim 3, characterized in that: The carbon fiber lattice prepreg has a carbon fiber lattice cloth content of 60-63wt%, and a carbon nanotube content of 0.70-0.75wt%; the carbon fiber filament content of the 0° carbon fiber prepreg and the 90° carbon fiber prepreg is 60-63wt%, and the carbon nanotube content is 0.70-0.75wt%.

6. A method for preparing a carbon fiber composite material for manufacturing a special shoe head according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1, preparing carbon fiber prepreg; Step 2: The carbon fiber prepreg in step 1 is cured at 40-50° C. for 36-48 hours; Step three, cutting the aging treated carbon fiber prepreg into finished carbon fiber prepreg in the shape of the molding mold, stacking the finished carbon fiber prepreg into a preformed toe cap by manual lamination, and demolding and trimming after hot pressing to obtain a finished carbon fiber safety toe cap.

7. The method for preparing a carbon fiber composite material for manufacturing a special shoe head according to claim 6, characterized in that: The carbon fiber prepreg in step 1 is a carbon fiber lattice prepreg, and the preparation method of the carbon fiber lattice prepreg is as follows: S1. Modifying the surface active functional groups of the carbon fiber woven fabric; at the same time, uniformly mixing the accurately measured matrix resin, low shrinkage resin, initiator, crosslinking agent, styrene, magnesium oxide, defoamer, release agent, and carbon nanotubes to obtain a mixture, and coating the mixture on a release paper for semi-curing to obtain a plastic resin film; S2. Preheat and press two plastic resin films onto the upper and lower surfaces of the carbon fiber lattice cloth modified with surface active functional groups, respectively. The mass ratio of the two plastic resin films to the carbon fiber lattice cloth modified with surface active functional groups is (60-64): (36-40), thereby obtaining a carbon fiber lattice prepreg cloth.

8. The method for preparing a carbon fiber composite material for manufacturing a special shoe head according to claim 6, characterized in that: The carbon fiber prepreg in step 1 is a carbon fiber lattice prepreg, and the preparation method of the carbon fiber lattice prepreg is as follows: S1. The carbon fiber lattice is modified with surface active functional groups; at the same time, accurately measured matrix resin, low shrinkage resin, initiator, cross-linking agent, styrene, magnesium oxide, defoaming agent, release agent, and carbon nanotubes are mixed uniformly to obtain a mixture; S2. The mixture is respectively applied to the upper and lower surfaces of the carbon fiber lattice modified with surface active functional groups, and dried and semi-cured to obtain the carbon fiber lattice prepreg. The mass ratio of the carbon fiber lattice modified with surface active functional groups to the mixture in the carbon fiber lattice prepreg is (60-64): (36-40).

9. The method for preparing a carbon fiber composite material for manufacturing a special shoe head according to claim 6, characterized in that: The carbon fiber prepreg in step 1 includes a 0° carbon fiber prepreg, and the preparation method of the 0° carbon fiber prepreg is as follows: S1. Modifying the carbon fiber filaments with surface active functional groups; At the same time, accurately measured base resin, low shrinkage resin, initiator, cross-linking agent, styrene, magnesium oxide, defoamer, release agent, and carbon nanotubes are uniformly mixed to obtain a mixture, and the mixture is coated on release paper for semi-curing treatment to obtain a plastic resin film; S2. The carbon fiber filaments modified with surface active functional groups are passed between two yarn guide plates, and the carbon fiber filaments between the yarn guide plates are evenly spaced along the 0° direction. The plastic resin film is preheated and pressed on the upper and lower surfaces of the 0° carbon fiber filament layer modified with surface active functional groups between the two yarn guide plates to obtain a 0° carbon fiber prepreg. The addition amount of 0° carbon fiber filaments in the 0° carbon fiber prepreg is 60-64wt%.

10. The method for preparing a carbon fiber composite material for manufacturing a special toe cap according to claim 6, characterized in that: The carbon fiber prepreg in step 1 includes a 90° carbon fiber prepreg, and the preparation method of the 90° carbon fiber prepreg is as follows: S1. Modifying the carbon fiber filaments with surface active functional groups; At the same time, accurately measured base resin, low shrinkage resin, initiator, cross-linking agent, styrene, magnesium oxide, defoamer, release agent, and carbon nanotubes are uniformly mixed to obtain a mixture, and the mixture is coated on release paper for semi-curing treatment to obtain a plastic resin film; S2. The carbon fiber filaments modified with surface active functional groups are passed between two yarn guide plates, and the carbon fiber filaments between the yarn guide plates are evenly arranged along the 90° direction. The plastic resin film is 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 guide plates to obtain a 90° carbon fiber prepreg. The addition amount of 90° carbon fiber filaments in the 90° carbon fiber prepreg is 60-64wt%.

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