High elastic modulus carbon fiber plate and its preparation process and application

Abstract

The present invention relates to the technical field of shoe materials, and in particular to a high elastic modulus carbon fiber plate and a preparation process and application thereof, which specifically comprises the following steps: S1, preparing prepreg: a first protective film, a first carbon fiber fabric coated with epoxy resin on the surface, an intermediate sheet, a second carbon fiber fabric and a second protective film coated with epoxy resin on the surface are sequentially laminated, firstly laminated by a cold press roller and then laminated by a hot press roller, and the sides of the first carbon fiber fabric and the second carbon fiber fabric are coated with a treatment liquid by a fixed point roller before lamination; S2, lamination, hot pressing and curing; S3, high temperature carbonization; S4, densification, and the finished product density is 1.55g / cm 3 The present invention innovatively proposes to use a first protective film, a first carbon fiber fabric, an intermediate sheet, a second carbon fiber fabric and a second protective film for film pressing to achieve the penetration of epoxy resin inside the fabric, and strictly control the temperature and pressure parameters of the pressing process to improve the resin impregnation performance in the carbon fiber prepreg.

Description

Technical Field

[0001] The invention relates to the technical field of shoe materials, and in particular to a high elastic modulus carbon fiber plate and a preparation process and application thereof. Background Art

[0002] As a composite material of resin and carbon fiber, carbon fiber plate can ensure the flexibility of the sole while enhancing its support and stability, especially when the wearer makes large turns, jumps, and runs, so that the sole will not be over-twisted, and the protection of the foot will be improved. Carbon fiber plate has been widely used in the sports shoe industry to improve sports performance. The application value of carbon fiber plate in the field of sports shoes is to strengthen the bottom of the midsole of sports shoes, improve structural rigidity, ensure the stability of the arch, and provide anti-torsion protection. Most carbon plate structures are in "X" or "Y" shapes.

[0003] The prepreg process is one of the main processes for producing carbon fiber boards. Prepreg is mainly prepared by membrane pressure impregnation or solution impregnation. (1) The solution impregnation method is to prepare the resin into a resin solution of a certain concentration through a solvent, and then pull the fiber reinforcement through a groove and heat it to evaporate the solvent and solidify the resin to adhere to the fiber reinforcement. The main disadvantage of this method is that the solvent does not evaporate sufficiently, which easily forms voids inside the material. (2) The membrane pressure impregnation method is to press a layer of film with resin on both sides of the fiber reinforcement, and use the pressure of the roller to squeeze the resin into the voids of the fiber reinforcement. Although there is no solvent volatilization in this method, the resin has poor wettability on carbon fiber, and it is difficult to ensure that the resin will fully infiltrate the fiber reinforcement. Summary of the invention

[0004] The invention aims to provide a high elastic modulus carbon fiber plate and a preparation process and application thereof, which can improve the impregnation performance of resin in carbon fiber prepreg.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0006] The high elastic modulus carbon fiber plate preparation process specifically includes the following steps:

[0007] S1, preparing a prepreg roll: a first protective film, a first carbon fiber fabric coated with epoxy resin on the surface, an intermediate sheet, a second carbon fiber fabric and a second protective film coated with epoxy resin on the surface are sequentially laminated, first laminated by a cold press roller for the first time and then laminated by a hot press roller for the second time, cooled and rolled up to obtain a prepreg roll; wherein, a side of the first carbon fiber fabric close to the intermediate sheet and a side of the second carbon fiber fabric close to the intermediate sheet are coated with a treatment liquid by a fixed-point roller before lamination, wherein the treatment liquid is a mixed liquid of an aqueous epoxy resin curing agent and a diluent containing an epoxy resin-philic molecular structure, and is coated by a fixed-point roller on the transverse yarns of the first carbon fiber fabric and the second carbon fiber fabric parallel to the width extension direction thereof;

[0008] S2, laying and hot pressing curing: unwinding the prepreg roll of step S1, separating to obtain an intermediate sheet and two prepreg sheets, cutting the prepregs and stacking them in a mold, and curing them by heating and pressing to obtain a cured material;

[0009] S3, high temperature carbonization: carbonizing the solidified material in step S2 by stepwise temperature increase to obtain a carbonized material;

[0010] S4, densification: the carbonized material of step S3 is densified by impregnation-carbonization process, and the finished product density is 1.55g / cm 3 above.

[0011] Preferably, the intermediate sheet in step S1 is glass paper, and the pressure of the first pressing is 0.6MPa-0.8MPa, and the temperature is 10°C-15°C; the pressure of the second pressing is 0.25MPa-0.35MPa, and the temperature is 40°C-50°C.

[0012] Preferably, the first protective film and the second protective film in step S1 are polyethylene films.

[0013] Preferably, the number of layers in step S2 is 8-10 layers.

[0014] Preferably, the heating and pressurizing of step S2 are specifically as follows: treating at a temperature of 90°C to 95°C and a pressure of 0.6MPa-0.8MPa for 40min-60min; heating and pressurizing, treating at a temperature of 135°C to 145°C and a pressure of 1.5MPa-2.0MPa for 30min-40min; heating and pressurizing again, treating at a temperature of 190°C to 200°C and a pressure of 4.5MPa-5.5MPa for 120min-130min.

[0015] Preferably, the step-by-step temperature carbonization in step S3 is as follows: under nitrogen protection, heating to 500°C-550°C at a heating rate of 6.0°C / min-6.5°C / min, and keeping warm for 1-1.5 hours; then heating to 800°C-850°C at a heating rate of 3.0°C / min-4.0°C / min, and keeping warm for 1-1.5 hours; then heating to 1150°C-1250°C at a heating rate of 2.0°C / min-2.5°C / min, and keeping warm for 2-3 hours; then step-by-step cooling to below 100°C.

[0016] Preferably, the densification treatment of step S4 is specifically as follows: placing the carbonized material in a high-pressure impregnation furnace, pressurizing it to 5MPa-8MPa, filling asphalt or resin in the gaps of the carbonized material, and then carbonizing it at a high temperature of 800℃-1200℃; the mass ratio of the carbonized material to the asphalt or resin is 1:1.8-2.0; and repeating the impregnation-carbonization 1-3 times.

[0017] The present invention further provides a carbon fiber plate with high elastic modulus produced by the above-mentioned preparation process.

[0018] The present invention further provides an application of a high elastic modulus carbon fiber plate in a shoe sole.

[0019] Preferably, the carbon fiber plate is X-shaped or Y-shaped.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention focuses on improving the preparation of prepreg. Different from the traditional membrane pressure impregnation method, it innovatively proposes to use a first protective film, a first carbon fiber fabric, an intermediate sheet, a second carbon fiber fabric and a second protective film for membrane pressure to achieve the penetration of epoxy resin into the fabric, and strictly controls the temperature and pressure parameters of the pressing process to improve the resin's impregnation performance in the carbon fiber prepreg.

[0022] The first pressing is high pressure and low temperature while the second pressing is low pressure and high temperature. High pressure and low temperature mainly rely on the mechanical force of pressing to force the epoxy resin to penetrate in three directions of the fabric. Low temperature is beneficial to avoid the epoxy resin from flowing too fast in the thickness direction of the single-layer carbon fiber fabric and can well control the penetration front to reach the interface between the carbon fiber fabric and the intermediate sheet. When the epoxy resin contacts the diluent and the water-based epoxy resin curing agent, the dilution effect of the diluent and the emulsification effect of the water-based epoxy resin curing agent are used to reduce the viscosity of the epoxy resin. The fixed-point coating on the transverse yarns of the carbon fiber fabric is beneficial to the diffusion of the carbon fiber fabric in the transverse direction and reduces the difference with the axial penetration, thereby achieving uniform penetration in the surface. In addition, the existence of the intermediate sheet enables two prepregs to be prepared at the same time, thereby improving production efficiency and improving impregnation quality.

[0023] Furthermore, the present invention applies a water-based epoxy resin curing agent on the side of the carbon fiber fabric at a fixed point by a roller. The neutralization degree of 50% is beneficial to the emulsification of the curing agent on the epoxy resin, and the complexing with boron trifluoride is beneficial to inhibiting the curing effect of the curing agent on the epoxy resin. The water-based epoxy resin curing agent and the diluent are combined to allow the epoxy resin to undergo viscosity thixotropy after the first pressing at low temperature and high pressure.

[0024] Moreover, the resin in the prepreg of the present invention is fully impregnated with no pores. Compared with the traditional membrane pressure impregnation method, the prepreg obtained by the present invention has a larger volume fraction of carbon fiber, which helps to improve the overall impact resistance and elastic modulus of the carbon fiber board. At the same time, the obtained finished product has a high density and can reduce the densification cycle. DETAILED DESCRIPTION Example 1

[0025] This embodiment provides a high elastic modulus carbon fiber plate, which is X-shaped and is used as a midfoot reinforcement sheet for a shoe sole. The preparation process of the carbon fiber plate specifically includes the following steps: S1, preparing a prepreg roll; S2, laying, hot pressing and curing; S3, high temperature carbonization; S4, densification.

[0026] In step S1, a first protective film, a first carbon fiber fabric coated with epoxy resin on the surface, an intermediate sheet, a second carbon fiber fabric and a second protective film coated with epoxy resin on the surface are laminated in sequence through a prepreg composite production line at a speed of 1.5 m / min, wherein the first protective film and the second protective film are polyethylene films, the intermediate sheet is cellophane, the grade of epoxy resin is SCR3251, and the viscosity at room temperature is 176 mPa·s; the first carbon fiber fabric and the second carbon fiber fabric use 12K carbon fiber tows, the same organization is 2×2 twill, and the surface density is 380 g / m 2 .

[0027] During lamination, the first carbon fiber fabric, the middle sheet and the second carbon fiber fabric are firstly combined together to complete the front lamination, and then transferred to the back to be laminated with the first protective film and the second protective film to complete the back lamination. Before the back lamination, the side of the first carbon fiber fabric away from the middle sheet and the side of the second protective film close to the second carbon fiber fabric are respectively coated with epoxy resin, and the coating amount of epoxy resin is 200g / m 2 Before the front-end bonding, the side of the first carbon fiber fabric close to the middle piece and the side of the second carbon fiber fabric close to the middle piece are respectively coated with treatment liquid by a fixed roller, and the fixed roller is coated on the transverse yarns of the first carbon fiber fabric and the second carbon fiber fabric parallel to their width extension direction.

[0028] The treatment liquid in this embodiment is a mixture of a water-based epoxy resin curing agent and a diluent containing an epoxy resin-philic molecular structure, the mass ratio of the water-based epoxy resin curing agent to the diluent is 2.5:1, and the roller coating amount is 90g / m2 Among them: the diluent is active diluent 2010P, the water-based epoxy resin curing agent adopts ethylenediamine and epoxy resin E-51 in a molar ratio of 2:1, and then neutralized with glacial acetic acid, the neutralization degree is 50%, and finally boron trifluoride ether complex is added to complex boron trifluoride in the remaining amino group.

[0029] After lamination, the composite material is first pressed on a cold press roller at a temperature of 10°C and a pressure of 0.7 MPa, and then pressed on a hot press roller for a second time at a temperature of 45°C and a pressure of 0.3 MPa. Finally, it is cooled and rolled up to obtain a prepreg roll.

[0030] In step S2, the prepreg roll of step S1 is unwound and separated to obtain the middle sheet and two prepreg sheets, the prepreg is cut and stacked in a mold, the number of layers is 10, the plying order is 0° and 90° alternately, and the curing treatment is carried out by heating and pressurizing to obtain a cured material. The heating and pressurizing are specifically as follows: treating at a temperature of 90°C and a pressure of 0.8MPa for 60min; heating to 140°C at a heating rate of 2.0°C / min and pressurizing to a pressure of 2.0MPa, and treating under this condition for 30min; heating to 190°C at a heating rate of 1.0°C / min and pressurizing to a pressure of 5.5MPa, and treating under this condition for 120min.

[0031] In step S3, the solidified material of step S2 is subjected to step-by-step temperature carbonization to obtain a carbonized material. The step-by-step temperature carbonization is specifically as follows: under nitrogen protection, the temperature is raised to 550°C at a heating rate of 6.0°C / min, and kept at this temperature for 1.5 hours; then the temperature is raised to 850°C at a heating rate of 3.5°C / min, and kept at this temperature for 1 hour; then the temperature is raised to 1250°C at a heating rate of 2.5°C / min, and kept at this temperature for 2.5 hours; then the temperature is lowered to 750°C at a cooling rate of 4.0°C / min; the temperature is lowered to 350°C at a cooling rate of 2.0°C / min, and finally the temperature is naturally lowered to below 100°C.

[0032] In step S4, the carbonized material of step S3 is densified by an impregnation-carbonization process, specifically: the carbonized material is placed in a high-pressure impregnation furnace, pressurized to 6MPa, the gaps in the carbonized material are filled with asphalt, and then carbonized at 1100°C; the mass ratio of the carbonized material to the asphalt is 1:2.0; the impregnation-carbonization is repeated twice, and the finished product density is 1.62g / cm 3 Above, elastic modulus 208GPa. Example 2

[0033] This embodiment provides a high elastic modulus carbon fiber plate, which is Y-shaped and is used as a midfoot reinforcement sheet for a shoe sole. The preparation process of the carbon fiber plate specifically includes the following steps: S1, preparing a prepreg roll; S2, laying, hot pressing and curing; S3, high temperature carbonization; S4, densification.

[0034] In step S1, the first protective film, the first carbon fiber fabric coated with epoxy resin on the surface, the intermediate sheet, the second carbon fiber fabric and the second protective film coated with epoxy resin on the surface are laminated in sequence through a prepreg composite production line at a speed of 1.5 m / min, wherein the first protective film and the second protective film are polyethylene films, the intermediate sheet is cellophane, the grade of epoxy resin is SCR3251, and the viscosity at room temperature is 176 mPa·s; the first carbon fiber fabric and the second carbon fiber fabric are 12K carbon fiber tows, the organization is the same, both are plain weave, and the surface density is 200 g / m 2 .

[0035] During lamination, the first carbon fiber fabric, the middle sheet and the second carbon fiber fabric are firstly combined together to complete the front lamination, and then transferred to the back to be laminated with the first protective film and the second protective film to complete the back lamination. Before the back lamination, the side of the first carbon fiber fabric away from the middle sheet and the side of the second protective film close to the second carbon fiber fabric are respectively coated with epoxy resin, and the coating amount of epoxy resin is 200g / m 2 Before the front-end bonding, the side of the first carbon fiber fabric close to the middle piece and the side of the second carbon fiber fabric close to the middle piece are respectively coated with treatment liquid by a fixed roller, and the fixed roller is coated on the transverse yarns of the first carbon fiber fabric and the second carbon fiber fabric parallel to their width extension direction.

[0036] The treatment liquid in this embodiment is a mixture of a water-based epoxy resin curing agent and a diluent containing an epoxy resin-philic molecular structure, the mass ratio of the water-based epoxy resin curing agent to the diluent is 2.5:1, and the roller coating amount is 85g / m 2 Among them: the diluent is active diluent 2010P, the water-based epoxy resin curing agent adopts ethylenediamine and epoxy resin E-51 in a molar ratio of 2:1, and then neutralized with glacial acetic acid, the neutralization degree is 50%, and finally boron trifluoride ether complex is added to complex boron trifluoride in the remaining amino group.

[0037] After lamination, the composite material is first pressed on a cold press roller at a temperature of 12°C and a pressure of 0.7 MPa, and then pressed on a hot press roller for a second time at a temperature of 40°C and a pressure of 0.3 MPa. Finally, it is cooled and rolled up to obtain a prepreg roll.

[0038] In step S2, the prepreg roll of step S1 is unwound and separated to obtain the middle sheet and two prepreg sheets, the prepreg is cut and stacked in a mold, the number of layers is 10, the plying order is 0° and 90° alternately, and the curing treatment is carried out by heating and pressurizing to obtain a cured material. The specific heating and pressurizing are: treating at a temperature of 95°C and a pressure of 0.6MPa for 50min; heating to 145°C at a heating rate of 1.8°C / min and pressurizing to a pressure of 2.0MPa, and treating under this condition for 30min; heating to 200°C at a heating rate of 1.0°C / min and pressurizing to a pressure of 5MPa, and treating under this condition for 120min.

[0039] In step S3, the solidified material of step S2 is subjected to step-by-step temperature carbonization to obtain a carbonized material. The step-by-step temperature carbonization is specifically as follows: under nitrogen protection, the temperature is raised to 550°C at a heating rate of 6°C / min, and kept at this temperature for 1.5 hours; then the temperature is raised to 800°C at a heating rate of 4.0°C / min, and kept at this temperature for 1.5 hours; then the temperature is raised to 1200°C at a heating rate of 2°C / min, and kept at this temperature for 2.5 hours; then the temperature is lowered to 700°C at a cooling rate of 4.0°C / min; the temperature is lowered to 300°C at a cooling rate of 2.0°C / min, and finally the temperature is naturally lowered to below 100°C.

[0040] In step S4, the carbonized material of step S3 is densified by an impregnation-carbonization process, specifically: the carbonized material is placed in a high-pressure impregnation furnace, pressurized to 6 MPa, phenolic resin is filled in the gaps of the carbonized material, and then carbonized at 900°C; the mass ratio of the carbonized material to the phenolic resin is 1:2.0; the impregnation-carbonization is repeated twice, and the finished product density is 1.65 g / cm 3 , elastic modulus 215GPa.

[0041] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention shall be defined by the attached claims and their equivalents.

Claims

1. A process for preparing a high elastic modulus carbon fiber plate, characterized in that: The specific steps include: S1, preparing a prepreg roll: a first protective film, a first carbon fiber fabric coated with epoxy resin on the surface, an intermediate sheet, a second carbon fiber fabric and a second protective film coated with epoxy resin on the surface are sequentially laminated, first laminated by a cold press roller for the first time and then laminated by a hot press roller for the second time, cooled and rolled up to obtain a prepreg roll; wherein, a side of the first carbon fiber fabric close to the intermediate sheet and a side of the second carbon fiber fabric close to the intermediate sheet are coated with a treatment liquid by a fixed-point roller before lamination, wherein the treatment liquid is a mixed liquid of an aqueous epoxy resin curing agent and a diluent containing an epoxy resin-philic molecular structure, and is coated by a fixed-point roller on the transverse yarns of the first carbon fiber fabric and the second carbon fiber fabric parallel to the width extension direction thereof; S2, laying and hot pressing curing: unwinding the prepreg roll of step S1, separating to obtain an intermediate sheet and two prepreg sheets, cutting the prepregs and stacking them in a mold, and curing them by heating and pressing to obtain a cured material; S3, carbonizing the solidified material in step S2 by step-by-step temperature increase to obtain a carbonized material; S4, densification: the carbonized material of step S3 is densified by impregnation-carbonization process, and the finished product density is 1.55g / cm 3 above; The pressure of the first pressing in step S1 is 0.6MPa-0.8MPa and the temperature is 10℃-15℃; the pressure of the second pressing is 0.25MPa-0.35MPa and the temperature is 40℃-50℃; The mass ratio of the waterborne epoxy resin curing agent to the diluent is 2.5:

1. The waterborne epoxy resin curing agent is prepared by reacting ethylenediamine with epoxy resin E-51 in a molar ratio of 2:1, and then neutralized with glacial acetic acid with a neutralization degree of 50%. Finally, boron trifluoride ether complex is added to complex boron trifluoride in the remaining amino groups.

2. The process for preparing a high elastic modulus carbon fiber board according to claim 1, characterized in that: The first protective film and the second protective film in step S1 are polyethylene films.

3. The process for preparing a high elastic modulus carbon fiber board according to claim 1, characterized in that: The number of layers in step S2 is 8-10 layers.

4. The process for preparing a high elastic modulus carbon fiber board according to claim 1, characterized in that: The heating and pressurizing of step S2 are specifically as follows: treating at a temperature of 90°C to 95°C and a pressure of 0.6MPa-0.8MPa for 40min-60min; heating and pressurizing at a temperature of 135°C to 145°C and a pressure of 1.5MPa-2.0MPa for 30min-40min; heating and pressurizing again at a temperature of 190°C to 200°C and a pressure of 4.5MPa-5.5MPa for 120min-130min.

5. The process for preparing a high elastic modulus carbon fiber board according to claim 1, characterized in that: The step-by-step temperature carbonization in step S3 is specifically as follows: under nitrogen protection, the temperature is increased to 500°C-550°C at a heating rate of 6.0°C / min-6.5°C / min, and kept warm for 1-1.5 hours; then the temperature is increased to 800°C-850°C at a heating rate of 3.0°C / min-4.0°C / min, and kept warm for 1-1.5 hours; then the temperature is increased to 1150°C-1250°C at a heating rate of 2.0°C / min-2.5°C / min, and kept warm for 2-3 hours; then the temperature is step-down to below 100°C.

6. The process for preparing a high elastic modulus carbon fiber board according to claim 1, characterized in that: The densification treatment of step S4 is specifically as follows: placing the carbonized material in a high-pressure impregnation furnace, pressurizing it to 5MPa-8MPa, filling the gaps in the carbonized material with asphalt or resin, and then carbonizing it at a high temperature of 800℃-1200℃; the mass ratio of the carbonized material to the asphalt or resin is 1:1.8-2.0; and repeating the impregnation-carbonization 1-3 times.