A forged pattern aramid sheet molding compound and its preparation method

Abstract

The present invention relates to the technical field of aramid fiber composite materials, and particularly relates to a forged pattern aramid sheet molding compound and a preparation method thereof. The forged pattern aramid sheet molding compound includes aramid colored fiber unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg, and a flame-retardant epoxy resin. After the aramid colored fiber, aramid fiber, and aramid woven fabric are respectively subjected to sizing treatment, they are then impregnated with the flame-retardant epoxy resin to obtain the aramid colored fiber unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg. The sizing agent used in the sizing treatment includes a water-soluble polyamide resin prepared by polymerizing α,ω-dicarboxy polyethylene glycol and polyetheramine. In view of the problems of insufficient aesthetics and poor impact resistance of the forged pattern carbon fiber sheet molding compound in the prior art, the present invention provides a forged pattern aramid sheet molding compound and a preparation method thereof. The forged pattern aramid sheet molding compound has the advantages of beauty, strong designability, impact resistance, and flame retardancy.

Description

Technical Field

[0001] The present invention relates to a forged pattern aramid sheet molding compound and a preparation method thereof, belonging to the technical field of aramid fiber composite materials. Background Art

[0002] Aramid fibers have high specific strength, high specific modulus, high temperature resistance, acid and alkali resistance, light weight, excellent wear resistance and impact resistance, and thus are widely used in fields such as aerospace, rail transit, and new energy vehicles. However, with the development of fields such as new energy vehicles and low-altitude flight, the demand for lightweight composite materials is increasing continuously, and more requirements are put forward for their appearance texture and decoration.

[0003] Sheet molding compound emerged in the late 1950s and has received wide attention since its appearance. So far, the automotive parts that can be replaced by sheet molding compound (SMC) mainly include: roof, bumper, side panel - inner lining assembly, radiator grille, engine hood, side panel, trunk lid, battery tray, interior panel, etc. Forged pattern sheet molding compound, as an advanced new composite material, has the advantages of light weight, high specific strength, strong design flexibility, high production efficiency, and easy preparation of complex configuration parts. Due to its unique marble texture and the characteristics of light weight and high strength, it has gradually replaced continuous fiber reinforced composite materials and become a commonly used material for new energy vehicles and low-altitude aircraft.

[0004] In recent years, with the development of the economy, people have put forward more and more requirements for forged pattern sheet molding compound. Not only do they require the forged pattern sheet molding compound to have the properties of light weight and high strength, but they also hope it to be more beautiful and decorative. Currently, carbon fiber sheet molding compound is a commonly used material, which has marble texture, high performance and light weight. Chinese Patent CN118144372A proposes a forged pattern carbon fiber sheet molding compound and a preparation method thereof. Through this method, the manufacture of complex shapes of forged texture carbon fiber composite materials can be realized, and there are no defects such as pinholes, bubbles, and lack of glue on the product surface. Chinese Patent Application CN118752802A proposes a gold foil modified carbon fiber sheet molding compound, and gold foil is sprinkled on the outer surface of the carbon fiber base sheet to improve its aesthetics. However, due to the intrinsic black color of carbon fiber and the inability to change its color, the design aesthetics is poor; in addition, due to the higher modulus of carbon fiber, its toughness and impact resistance are poor.

[0005] In addition, due to the inert and smooth characteristics of aramid fibers themselves, it is difficult to form a relatively good interfacial bond with the resin, and delamination and debonding are likely to occur between the aramid fibers and the resin during the preparation and use processes, resulting in a decrease in the mechanical properties of the prepared sheet molding compound. Therefore, it is of great significance to develop a forged pattern aramid sheet molding compound with flame retardancy, impact resistance, and multi-color design. Summary of the Invention

[0006] In view of the problems in the prior art such as insufficient aesthetics and poor impact resistance of forged pattern carbon fiber sheet molding compounds, the present invention provides a forged pattern aramid sheet molding compound and a preparation method thereof. The forged pattern aramid sheet molding compound has the advantages of beauty, strong designability, impact resistance and flame retardancy.

[0007] The technical solution for the present invention to solve the above technical problems is as follows: A forged pattern aramid sheet molding compound, which includes aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg and flame retardant epoxy resin;

[0008] After the aramid colored filaments, aramid fibers and aramid woven fabrics are respectively sized, they are impregnated with flame retardant epoxy resin to obtain the aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg;

[0009] The sizing agent used for sizing includes a water-soluble polyamide resin prepared by polymerizing α,ω-dicarboxyl polyethylene glycol and polyetheramine.

[0010] Further, the width of the aramid colored filament unidirectional prepreg is 15 - 20 mm;

[0011] The aramid colored filament unidirectional prepreg is composed of one or more of the three primary colors of red, yellow, blue and the colors formulated from these three primary colors.

[0012] Further, the aramid fiber unidirectional prepreg is obtained by impregnating a raw color aramid fiber unidirectional tape with flame retardant epoxy resin;

[0013] The aramid woven fabric prepreg is prepared by sizing and impregnating one or more of aramid plain weave fabrics and aramid twill weave fabrics with flame retardant epoxy resin.

[0014] Further, the preparation method of the water-soluble polyamide resin is as follows: Add pyridine, triphenyl phosphite, calcium chloride and lithium chloride to N-methylpyrrolidone, stir to completely dissolve calcium chloride and lithium chloride, then add polyetheramine and α,ω-dicarboxyl polyethylene glycol to the system, heat and stir until the system becomes completely clear, and then carry out a polymerization reaction under the protection of an inert gas. After the reaction is completed, a water-soluble polyamide resin is obtained through post-treatment operations.

[0015] Further, dissolve the water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 5 - 10 wt%, and then add a wetting agent accounting for 0.1 - 0.2% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0016] The present invention also discloses a preparation method of a forged pattern aramid sheet molding compound, and the preparation method is as follows:

[0017] S1. Size the aramid colored filaments, aramid fibers, and aramid woven fabrics, and then impregnate them with flame-retardant epoxy resin respectively to obtain aramid colored filament unidirectional prepregs, aramid fiber unidirectional prepregs, and aramid woven fabric prepregs;

[0018] S2. Cut the aramid colored filament unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain forged texture aramid fiber prepreg through pressing;

[0019] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, and then lay the release film, breather felt, and vacuum bag in sequence, and press in the flame-retardant epoxy resin through vacuum pumping to obtain a composite material; the side of the forged texture aramid fiber prepreg with short fiber bundles is attached to the mold cavity surface;

[0020] S4. Heat and pressurize the mold with the composite material laid in step S3 as a whole to achieve curing and molding to obtain the forged texture aramid sheet molding compound.

[0021] Further, in step S2, the length of the short fiber bundles is 20 mm - 40 mm; the laying thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 0.5 mm - 1.5 mm.

[0022] Further, in step S2, the pressing conditions are: temperature 145 - 155 °C, pressure 1.0 - 2.0 MPa, and time 60 - 120 min.

[0023] Further, the dosage of the flame-retardant epoxy resin accounts for 30% - 40% of the total mass of the forged texture aramid sheet molding compound.

[0024] Further, in step S4, during the curing and molding process, the injection pressure is 0.1 - 1.0 MPa; the heating is gradient heating, and the gradient heating process is: from room temperature, at a heating rate of 4 - 5 °C / min, heat up to 100 ± 2 °C, and then keep warm for 20 - 30 min; then continue to heat up to 145 ± 5 °C at a heating rate of 4 - 5 °C / min, and keep warm for 100 - 120 min.

[0025] The beneficial effects of the present invention are:

[0026] (1) The present invention uses the aramid colored filament unidirectional prepreg as the forged texture, which can overcome the disadvantages of the original carbon fiber forged texture with a single color and poor designability, can provide a more beautiful texture design, and the inherent flexibility of the aramid fiber can also improve the impact resistance of the product.

[0027] (2) The present invention uses aramid woven fabric prepreg as the raw material. Compared with the high modulus of carbon fiber woven fabric, it can improve the damage tolerance and impact resistance of the product, and the inherent flame retardancy of aramid fiber can also improve the flame retardant performance of the product.

[0028] (3) The present invention uses a self-made water-soluble polyamide resin as the sizing agent. Compared with traditional sizing agents, the water-soluble polyamide resin sizing agent is more environmentally friendly, and this sizing agent has a structure similar to that of aramid fiber, which can improve the adhesion of the resin to aramid fiber.

[0029] (4) The present invention uses a transparent and flame-retardant epoxy resin as the matrix resin, which can improve the flame retardant performance of the product and can more fully display the design and multi-color display of the product. Detailed implementation manners

[0030] The following makes a detailed description of the specific implementation manners of the present invention. The present invention can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used are only for describing specific implementation manners and do not limit the present invention.

[0032] A forged pattern aramid sheet molding compound, wherein the forged pattern aramid sheet molding compound includes aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg and flame-retardant epoxy resin;

[0033] After the aramid colored filaments, aramid fibers and aramid woven fabrics are respectively sized, and then impregnated with the flame-retardant epoxy resin to obtain the aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg;

[0034] The sizing agent used for sizing includes a water-soluble polyamide resin prepared by polymerizing α,ω-dicarboxyl polyethylene glycol and polyetheramine.

[0035] Specifically, the width of the aramid colored filament unidirectional prepreg is 15 - 20 mm;

[0036] The aramid colored filament unidirectional prepreg is composed of one or more of the three primary colors of red, yellow, and blue and the colors formulated from these three primary colors.

[0037] Specifically, the aramid fiber unidirectional prepreg is obtained by impregnating a raw color aramid fiber unidirectional tape with a flame-retardant epoxy resin;

[0038] The aramid woven fabric prepreg described above is prepared by sizing and impregnating one or more of aramid plain fabrics and aramid twill fabrics with a flame-retardant epoxy resin.

[0039] More specifically, the flame-retardant epoxy resin is a transparent, flame-retardant epoxy resin, which can be obtained by self-making or purchasing from the market, such as Huibo New Material GT-910A / B or GT-920A / B, etc.

[0040] More specifically, the aramid fiber used in the embodiments of the present invention is TH529S; the aramid colored yarn has the same model as the aramid fiber, but is only colored; in the aramid woven fabric, the aramid plain fabric is TH51081, and the aramid twill fabric is TH5209.

[0041] Specifically, the preparation method of the water-soluble polyamide resin is as follows: add pyridine, triphenyl phosphite, calcium chloride and lithium chloride to N-methylpyrrolidone, stir to completely dissolve calcium chloride and lithium chloride, then add polyetheramine and α,ω-dicarboxy poly(ethylene glycol) to the system and heat and stir until the system becomes completely clear, and then carry out a polymerization reaction under the protection of an inert gas. After the reaction is completed, a water-soluble polyamide resin is obtained through post-treatment operations.

[0042] More specifically, the polyetheramine is polyetheramine D400 (Mw = 400); the Mn of α,ω-dicarboxy poly(ethylene glycol) is 600.

[0043] Specifically, dissolve the water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 5-10 wt%, and then add a wetting agent accounting for 0.1-0.2% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0044] More specifically, the wetting agent is ECOROFCRCORE®3747 or HS-465.

[0045] More specifically, the sizing operation is as follows: put aramid fiber, aramid colored yarn and aramid woven fabric into the sizing agent for impregnation coating, after staying for 25-35 seconds, then dry in hot air at 95-100 °C for 4-5 minutes to form a uniform sizing layer, and obtain sized aramid fiber, aramid colored yarn and aramid woven fabric.

[0046] A preparation method of a forged pattern aramid sheet molding compound, the preparation method is as follows:

[0047] S1. Perform sizing treatment on aramid fiber, aramid colored yarn and aramid woven fabric, and then impregnate them with a flame-retardant epoxy resin respectively to obtain aramid colored yarn unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg;

[0048] S2. Cut the aramid colored filament unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain the forged texture aramid fiber prepreg through pressing.

[0049] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the release film, breather felt, and vacuum bag in sequence, and press in the flame retardant epoxy resin through vacuum pumping to obtain the composite material; the side of the forged texture aramid fiber prepreg with the short fiber bundles is attached to the mold cavity surface.

[0050] S4. Heat and pressurize the mold with the composite material laid in step S3 as a whole to achieve curing and forming to obtain the forged texture aramid sheet molding compound.

[0051] Specifically, in step S2, the length of the short fiber bundles is 20 mm - 40 mm; the sprinkling thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 0.5 mm - 1.5 mm.

[0052] In step S2, the pressing conditions are: temperature 145 - 155 °C, pressure 1.0 - 2.0 MPa, and time 60 - 120 min.

[0053] Specifically, the dosage of the flame retardant epoxy resin accounts for 30% - 40% of the total mass of the forged texture aramid sheet molding compound.

[0054] Specifically, in step S4, during the curing and forming process, the injection pressure is 0.1 - 1 MPa; the heating is gradient heating, and the gradient heating process is: from room temperature, at a heating rate of 4 - 5 °C / min, heat up to 100 ± 2 °C, and then keep warm for 20 - 30 min; then continue to heat up at a heating rate of 4 - 5 °C / min to 145 ± 5 °C, and keep warm for 100 - 120 min.

[0055] More specifically, the thickness of the finally obtained forged texture aramid sheet molding compound is 2 - 5 mm.

[0056] More specifically, the release film (SAFECLEAR®), breather felt (AIRMAT), and vacuum bag (AIRSAFETY®) used in the embodiments of the present invention are all purchased from Hebei Feom Composite Materials Co., Ltd.

[0057] Example 1

[0058] A forged pattern aramid sheet molding compound, which comprises aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg and flame retardant epoxy resin; the width of the aramid colored filament unidirectional prepreg is 20 mm, and the aramid colored filament unidirectional prepreg is red; the aramid woven fabric used for the aramid woven fabric prepreg is aramid plain weave fabric, and the flame retardant epoxy resin is Huibaixin Material GT-910A / B.

[0059] The preparation method of a forged pattern aramid sheet molding compound is as follows:

[0060] S1. Size the aramid colored filaments, aramid fibers and aramid woven fabrics, and then impregnate them with flame retardant epoxy resin respectively to obtain aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg and aramid woven fabric prepreg;

[0061] The preparation method of the sizing agent is: dissolve water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 8wt%, and then add a wetting agent accounting for 0.1% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0062] The preparation method of the water-soluble polyamide resin is: add 12 mL of N-methylpyrrolidone, 2 mL of pyridine, 6.2 g of triphenyl phosphite, 0.6 g of calcium chloride and 0.2 g of lithium chloride into a reaction flask, stir to completely dissolve calcium chloride and lithium chloride; continue to add 4 g of polyetheramine D400 and 6 g of α,ω-dicarboxyl polyethylene glycol to the system, heat and stir until the system becomes completely clear, then evacuate the system 3 times, displace the air in the system with nitrogen, seal the system, and stir and react in an oil bath at 110 °C for 36 h. After precipitation, filtration, washing and drying, the water-soluble polyamide resin can be obtained.

[0063] The specific operation of the sizing treatment is: put the aramid fibers, aramid colored filaments and aramid woven fabrics into the sizing agent for impregnation coating, after staying for 30 seconds, then dry in hot air at 100 °C for 5 minutes to form a uniform sizing layer, and obtain the sized aramid fibers, aramid colored filaments and aramid woven fabrics.

[0064] S2. Cut the aramid colored filament unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain the forged texture aramid fiber prepreg through pressing;

[0065] The length of the short fiber bundles is 20 mm; the spreading thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 0.5 mm - 1.0 mm;

[0066] The pressing conditions are: temperature 150 °C, pressure 1 MPa, and time 120 min.

[0067] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the separator film, breather felt, and vacuum bag in sequence, and press in the flame-retardant epoxy resin by vacuum pumping to obtain the composite material; the side of the forged texture aramid fiber prepreg with the chopped fiber bundles is in contact with the mold cavity surface;

[0068] S4. Heat and press the mold with the composite material laid in step S3 as a whole to achieve curing and molding to obtain the forged texture aramid sheet molding compound;

[0069] The dosage of the flame-retardant epoxy resin accounts for 36% of the total mass of the forged texture aramid sheet molding compound;

[0070] During the curing and molding process, the injection pressure is 0.3 MPa; the heating is gradient heating, and the gradient heating process is as follows: from room temperature, heat up to 100°C at a heating rate of 5°C / min, then keep warm for 30 min; then continue to heat up to 145°C at a heating rate of 5°C / min and keep warm for 120 min.

[0071] Example 2

[0072] A forged texture aramid sheet molding compound, which includes aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg, and flame-retardant epoxy resin; the width of the aramid colored filament unidirectional prepreg is 15 mm, and the aramid colored filament unidirectional prepreg is yellow; the aramid woven fabric used for the aramid woven fabric prepreg is aramid twill woven fabric, and the flame-retardant epoxy resin is Huibaixin Material GT-920A / B.

[0073] A preparation method of a forged texture aramid sheet molding compound is as follows:

[0074] S1. Size the aramid colored filaments, aramid fibers, and aramid woven fabrics, and then impregnate them with the flame-retardant epoxy resin respectively to obtain the aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg;

[0075] The preparation method of the sizing agent is: dissolve the water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 10 wt%, and then add a wetting agent accounting for 0.2% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0076] The preparation method of the water-soluble polyamide resin is as follows: Add 12 mL of N-methylpyrrolidone, 2 mL of pyridine, 6.2 g of triphenyl phosphite, 0.6 g of calcium chloride, and 0.2 g of lithium chloride into a reaction flask, and stir to completely dissolve calcium chloride and lithium chloride; continue to add 4 g of polyetheramine D400 and 6 g of α,ω-dicarboxyl polyethylene glycol to the system, heat and stir until the system becomes completely clear, then evacuate and exhaust the system 3 times, displace the air in the system with nitrogen, seal the system, and stir and react in an oil bath at 105 °C for 36 h. After precipitation, filtration, washing, and drying, the water-soluble polyamide resin can be obtained.

[0077] The specific operation of the sizing treatment is as follows: Put aramid fiber, aramid colored yarn, and aramid woven fabric into the sizing agent for impregnation coating. After a residence time of 20 seconds, dry with hot air at 95 °C for 5 minutes to form a uniform sizing layer, and obtain sized aramid fiber, aramid colored yarn, and aramid woven fabric.

[0078] S2. Cut the aramid colored yarn unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain the forged texture aramid fiber prepreg through pressing;

[0079] The length of the short fiber bundles is 30 mm; the spreading thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 1.0 mm - 1.5 mm;

[0080] The pressing conditions are: temperature 155 °C, pressure 2.0 MPa, and time 60 min.

[0081] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the release film, breather felt, and vacuum bag in sequence, and press in the flame-retardant epoxy resin through vacuum pumping to obtain the composite material; the side of the forged texture aramid fiber prepreg with short fiber bundles is attached to the mold cavity surface;

[0082] S4. Heat and pressurize the mold with the composite material laid in step S3 as a whole to achieve curing and forming to obtain the forged texture aramid sheet molding compound;

[0083] The dosage of the flame-retardant epoxy resin accounts for 30% of the total mass of the forged texture aramid sheet molding compound;

[0084] During the curing and forming process, the injection pressure is 0.5 MPa; the heating is gradient heating, and the gradient heating process is as follows: From room temperature, heat up at a heating rate of 4 °C / min to 102 °C, and then keep warm for 20 min; then continue to heat up at a heating rate of 4 °C / min to 150 °C, and keep warm for 100 min.

[0085] Example 3

[0086] A forged pattern aramid sheet molding compound, the forged pattern aramid sheet molding compound comprising aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg and a flame retardant epoxy resin; the width of the aramid colored filament unidirectional prepreg is 15 mm, and the aramid colored filament unidirectional prepreg is yellow; the aramid woven fabric used for the aramid woven fabric prepreg is an aramid plain weave fabric, and the flame retardant epoxy resin is Huibaixin Material GT-920A / B.

[0087] A preparation method of a forged pattern aramid sheet molding compound is as follows:

[0088] S1. Size the aramid colored filaments, aramid fibers and aramid woven fabric, and then impregnate them with the flame retardant epoxy resin respectively to obtain aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg;

[0089] The preparation method of the sizing agent is: dissolve water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 5 wt%, and then add a wetting agent accounting for 0.1% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0090] The preparation method of the water-soluble polyamide resin is: add 12 mL of N-methylpyrrolidone, 2 mL of pyridine, 6.2 g of triphenyl phosphite, 0.6 g of calcium chloride, and 0.2 g of lithium chloride into a reaction flask, stir to completely dissolve calcium chloride and lithium chloride; continue to add 4 g of polyetheramine D400 and 6 g of α,ω-dicarboxy poly(ethylene glycol) to the system, heat and stir until the system becomes completely clear, then evacuate the system 3 times, displace the air in the system with nitrogen, seal the system, and stir and react in an oil bath at 110 °C for 36 h. After precipitation, filtration, washing and drying, the water-soluble polyamide resin can be obtained.

[0091] The specific operation of the sizing treatment is: put the aramid fiber, aramid colored filament and aramid woven fabric into the sizing agent for impregnation coating, after staying for 30 seconds, then dry in hot air at 100 °C for 4 minutes to form a uniform sizing layer, and obtain the sized aramid fiber, aramid colored filament and aramid woven fabric.

[0092] S2. Cut the aramid colored filament unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain a forged texture aramid fiber prepreg through pressing;

[0093] The length of the short fiber bundles is 40 mm; the spreading thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 1.0 mm - 1.5 mm;

[0094] The pressing conditions are: temperature 145 °C, pressure 1.5 MPa, and time 100 min.

[0095] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the release film, breather felt, and vacuum bag in sequence, and press in the flame-retardant epoxy resin by vacuum pumping to obtain the composite material; the side of the forged texture aramid fiber prepreg with the chopped fiber bundles is in contact with the mold cavity surface;

[0096] S4. Heat and press the mold with the composite material laid in step S3 as a whole to achieve curing and molding to obtain the forged texture aramid sheet molding compound;

[0097] The dosage of the flame-retardant epoxy resin accounts for 40% of the total mass of the forged texture aramid sheet molding compound;

[0098] During the curing and molding process, the injection pressure is 1.0 MPa; the heating is gradient heating, and the gradient heating process is as follows: from room temperature, heat up at a heating rate of 5 °C / min to 98 °C, then keep warm for 30 min; then continue to heat up at a heating rate of 5 °C / min to 140 °C and keep warm for 120 min.

[0099] Comparative Example 1

[0100] The forged texture aramid sheet molding compound is prepared by the same method as in Example 1, except that: in this Comparative Example 1, the aramid woven fabric prepreg is not added. Specifically as follows:

[0101] A forged texture aramid sheet molding compound, the forged texture aramid sheet molding compound includes aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, and flame-retardant epoxy resin; the width of the aramid colored filament unidirectional prepreg is 8 - 10 mm, and the aramid colored filament unidirectional prepreg is red; the flame-retardant epoxy resin is Huibaixin Material GT-910A / B.

[0102] A preparation method of a forged texture aramid sheet molding compound is as follows:

[0103] S1. Size the aramid colored filaments and aramid fibers, and then impregnate them with the flame-retardant epoxy resin respectively to obtain the aramid colored filament unidirectional prepreg and the aramid fiber unidirectional prepreg;

[0104] The preparation method of the sizing agent is: dissolve the water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 8 wt%, and then add a wetting agent accounting for 0.1% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0105] The preparation method of the water-soluble polyamide resin is as follows: Add 12 mL of N-methylpyrrolidone, 2 mL of pyridine, 6.2 g of triphenyl phosphite, 0.6 g of calcium chloride, and 0.2 g of lithium chloride into a reaction flask, and stir to completely dissolve calcium chloride and lithium chloride; continue to add 4 g of polyetheramine D400 and 6 g of α,ω-dicarboxyl polyethylene glycol to the system, heat and stir until the system becomes completely clear, then evacuate the system 3 times, displace the air in the system with nitrogen, seal the system, and stir and react in an oil bath at 110 °C for 36 h. After precipitation, filtration, washing, and drying, the water-soluble polyamide resin can be obtained.

[0106] The specific operation of the sizing treatment is as follows: Put the aramid fiber and aramid colored yarn into the sizing agent for impregnation coating. After a residence time of 30 seconds, then dry in hot air at 100 °C for 5 minutes to form a uniform sizing layer, and obtain the sized aramid fiber and aramid colored yarn.

[0107] S2. Cut the aramid colored yarn unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain the forged texture aramid fiber prepreg through pressing;

[0108] The length of the short fiber bundles is 20 mm; the spreading thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 0.5 mm - 1.0 mm;

[0109] The pressing conditions are: temperature 150 °C, pressure 1.0 MPa, and time 120 min.

[0110] S3. Lay the forged texture aramid fiber prepreg on the mold cavity surface, then sequentially lay the release film, breather felt, and vacuum bag, and press in the flame-retardant epoxy resin through vacuum pumping to obtain the composite material; the side of the forged texture aramid fiber prepreg with short fiber bundles is attached to the mold cavity surface;

[0111] S4. Heat and press the mold with the composite material laid in step S3 as a whole to achieve curing and forming to obtain the forged texture aramid sheet molding compound;

[0112] The dosage of the flame-retardant epoxy resin accounts for 36% of the total mass of the forged texture aramid sheet molding compound;

[0113] During the curing and forming process, the injection pressure is 0.3 MPa; the heating is gradient heating, and the gradient heating process is: from room temperature, increase the temperature at a heating rate of 5 °C / min to 100 °C, then keep it warm for 30 min; then continue to increase the temperature at a heating rate of 5 °C / min to 145 °C, and keep it warm for 120 min.

[0114] Comparative Example 2

[0115] The forged pattern aramid sheet molding compound was prepared by the same method as in Example 1, except that: in this Comparative Example 2, the aramid colored fiber unidirectional prepreg and the aramid fiber unidirectional prepreg were replaced with a forged pattern carbon fiber prepreg. Specifically as follows:

[0116] A forged pattern aramid sheet molding compound, the forged pattern aramid sheet molding compound includes a forged pattern carbon fiber prepreg, an aramid woven fabric prepreg, and a flame retardant epoxy resin; the forged pattern carbon fiber prepreg is prepared from Zhongfu Shenying T700 / 12k carbon fiber bundles; the aramid woven fabric used in the aramid woven fabric prepreg is an aramid plain weave fabric (TH51081), and the flame retardant epoxy resin is Huibaixin Material GT-910A / B.

[0117] A method for preparing a forged pattern aramid sheet molding compound is as follows:

[0118] S1. The carbon fiber bundles and the aramid woven fabric are sized, and then impregnated with the flame retardant epoxy resin respectively to obtain a carbon fiber unidirectional prepreg and an aramid woven fabric prepreg;

[0119] The sizing agent is prepared as follows: water-soluble polyamide resin is dissolved in water to prepare an aqueous solution with a concentration of 8wt%, and then a wetting agent accounting for 0.1% of the mass of the aqueous solution is added to the aqueous solution, which is the sizing agent.

[0120] The preparation method of the water-soluble polyamide resin is as follows: add 12 mL of N-methylpyrrolidone, 2 mL of pyridine, 6.2 g of triphenyl phosphite, 0.6 g of calcium chloride, and 0.2 g of lithium chloride into a reaction flask, stir to completely dissolve calcium chloride and lithium chloride; continue to add 4 g of polyetheramine D400 and 6 g of α,ω-dicarboxyl polyethylene glycol to the system, heat and stir until the system becomes completely clear, then evacuate the system 3 times, displace the air in the system with nitrogen, seal the system, and stir and react in an oil bath at 110°C for 36 h. After precipitation, filtration, washing and drying, the water-soluble polyamide resin can be obtained.

[0121] The specific operation of the sizing treatment is as follows: put the forged pattern carbon fiber and the aramid woven fabric into the sizing agent for impregnation coating, after staying for 30 seconds, then dry in hot air at 100°C for 5 minutes to form a uniform sizing layer, and obtain the sized aramid fiber, forged pattern carbon fiber and aramid woven fabric.

[0122] S2. Cut the carbon fiber unidirectional prepreg into the same size as the aramid colored fiber unidirectional prepreg, then evenly sprinkle it on the carbon fiber unidirectional prepreg, and then obtain a forged texture carbon fiber prepreg through pressing;

[0123] The spreading thickness of the forged pattern carbon fiber prepreg is 0.5 mm - 1.0 mm;

[0124] The pressing conditions are as follows: temperature 150°C, pressure 1.0 MPa, and time 120 min.

[0125] S3. Lay the forged-texture carbon fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the release film, breather felt, and vacuum bag in sequence, and press in the flame-retardant epoxy resin by vacuum pumping to obtain the composite material; the side of the forged-texture aramid fiber prepreg with the forged texture carbon fiber prepreg is attached to the mold cavity surface.

[0126] S4. Heat and pressurize the mold with the composite material laid in step S3 as a whole to achieve curing and molding to obtain the forged-texture aramid sheet molding compound.

[0127] The dosage of the flame-retardant epoxy resin accounts for 36% of the total mass of the forged-texture aramid sheet molding compound.

[0128] During the curing and molding process, the injection pressure is 0.3 MPa; the heating is gradient heating, and the gradient heating process is as follows: from room temperature, heat up to 100°C at a heating rate of 5°C / min, then keep warm for 30 min; then continue to heat up to 145°C at a heating rate of 5°C / min and keep warm for 120 min.

[0129] Comparative Example 3

[0130] The forged-texture aramid sheet molding compound is prepared by the same method as in Example 1, except that: in this Comparative Example 3, the flame-retardant epoxy resin is replaced with a conventional resin. Specifically as follows:

[0131] A forged-texture aramid sheet molding compound, which includes aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg, and resin; the width of the aramid colored filament unidirectional prepreg is 8 - 10 mm, and the aramid colored filament unidirectional prepreg is red; the aramid woven fabric used for the aramid woven fabric prepreg is aramid plain weave fabric, and the resin is Huibaixin AM-8931A / B.

[0132] A preparation method of a forged-texture aramid sheet molding compound is as follows:

[0133] S1. Size the aramid colored filaments, aramid fibers, and aramid woven fabric, and then impregnate them with resin respectively to obtain aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg.

[0134] The preparation method of the sizing agent is as follows: Dissolve the water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 8 wt%, and then add a wetting agent accounting for 0.1% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0135] The preparation method of the water-soluble polyamide resin is as follows: Add 12 mL of N-methylpyrrolidone, 2 mL of pyridine, 6.2 g of triphenyl phosphite, 0.6 g of calcium chloride, and 0.2 g of lithium chloride into a reaction flask, and stir to completely dissolve calcium chloride and lithium chloride; continue to add 4 g of polyetheramine D400 and 6 g of α,ω-dicarboxyl polyethylene glycol into the system, heat and stir until the system becomes completely clear, then evacuate the system 3 times, displace the air in the system with nitrogen, seal the system, and stir and react in an oil bath at 110 °C for 36 h. After precipitation, filtration, washing, and drying, the water-soluble polyamide resin can be obtained.

[0136] The specific operation of the sizing treatment is as follows: Put aramid fiber, aramid colored fiber, and aramid woven fabric fiber into the sizing agent for impregnation coating. After a residence time of 30 seconds, dry in hot air at 100 °C for 5 minutes to form a uniform sizing layer, and obtain sized aramid fiber, aramid colored fiber, and aramid woven fabric.

[0137] S2. Cut the aramid colored fiber unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain a forged texture aramid fiber prepreg through pressing;

[0138] The length of the short fiber bundles is 20 mm; the spreading thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 0.5 mm - 1.0 mm;

[0139] The pressing conditions are: temperature 120 °C, pressure 1 MPa, and time 30 min.

[0140] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the release film, breather felt, and vacuum bag in sequence, and press the resin into the composite material through vacuum pumping; the side of the forged texture aramid fiber prepreg with short fiber bundles is attached to the mold cavity surface;

[0141] S4. Heat and pressurize the mold with the composite material laid in step S3 as a whole to achieve curing and forming to obtain the forged texture aramid sheet molding compound;

[0142] The dosage of the resin accounts for 36% of the total mass of the forged texture aramid sheet molding compound;

[0143] During the curing and forming process, the injection pressure is 0.3 MPa; the heating is gradient heating, and the gradient heating process is: from room temperature, heat up to 100 °C at a heating rate of 5 °C / min, and then keep warm for 30 min; then continue to heat up to 145 °C at a heating rate of 5 °C / min and keep warm for 120 min.

[0144] Comparative Example 4

[0145] The forged texture aramid sheet molding compound was prepared by the same method as in Example 1, except that: in Comparative Example 4, the surfaces of the aramid fiber, aramid colored filament and aramid woven fabric were not sized. Specifically as follows:

[0146] A forged texture aramid sheet molding compound, the forged texture aramid sheet molding compound includes aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg and flame retardant epoxy resin; the width of the aramid colored filament unidirectional prepreg is 8-10 mm, and the aramid colored filament unidirectional prepreg is red; the aramid woven fabric used for the aramid woven fabric prepreg is aramid plain fabric, and the flame retardant epoxy resin is Huibaixin Material GT-910A / B.

[0147] A method for preparing a forged texture aramid sheet molding compound is as follows:

[0148] S1. Immerse aramid colored filaments, aramid fibers and aramid woven fabrics in flame retardant epoxy resin respectively to obtain aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg and aramid woven fabric prepreg;

[0149] S2. Cut the aramid colored filament unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain the forged texture aramid fiber prepreg through pressing;

[0150] The length of the short fiber bundles is 20 mm; the laying thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 0.5 mm - 1.0 mm;

[0151] The pressing conditions are: temperature 150 °C, pressure 1.0 MPa, and time 120 min.

[0152] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the release film, breather felt and vacuum bag in sequence, and press in the flame retardant epoxy resin through vacuum pumping to obtain a composite material; the side of the forged texture aramid fiber prepreg with short fiber bundles is attached to the mold cavity surface;

[0153] S4. Heat and press the mold with the composite material laid in step S3 as a whole to achieve curing and molding to obtain the forged texture aramid sheet molding compound;

[0154] The dosage of the flame retardant epoxy resin accounts for 36% of the total mass of the forged texture aramid sheet molding compound;

[0155] During the curing and forming process, the injection pressure of the glue is 0.3 MPa; the heating is gradient heating, and the gradient heating process is as follows: starting from room temperature, heating up to 100 °C at a heating rate of 5 °C / min, then holding for 30 min; then continuing to heat up to 145 °C at a heating rate of 5 °C / min and holding for 120 min.

[0156] Comparative Example 5

[0157] The forged pattern aramid sheet molding compound was prepared by the same method as in Example 1, except that: in this Comparative Example 5, the sizing agent was replaced with a conventional aqueous polyurethane resin (R025 sizing agent). Specifically as follows:

[0158] A forged pattern aramid sheet molding compound, which includes aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven fabric prepreg and flame retardant epoxy resin; the width of the aramid colored filament unidirectional prepreg is 8-10 mm, and the aramid colored filament unidirectional prepreg is red; the aramid woven fabric used for the aramid woven fabric prepreg is aramid plain weave fabric, and the flame retardant epoxy resin is Huibaixin Material GT-910A / B.

[0159] The preparation method of a forged pattern aramid sheet molding compound is as follows:

[0160] S1. Size the aramid colored filaments, aramid fibers and aramid woven fabrics, and then impregnate them with flame retardant epoxy resin respectively to obtain aramid colored filament unidirectional prepreg, aramid fiber unidirectional prepreg, and aramid woven fabric prepreg;

[0161] The preparation method of the sizing agent is: dissolve the aqueous polyurethane resin in water to prepare an aqueous solution with a concentration of 8 wt%, and then add a wetting agent accounting for 0.1% of the mass of the aqueous solution to the aqueous solution, which is the sizing agent.

[0162] The specific operation of the sizing treatment is: put the aramid fibers, aramid colored filaments and aramid woven fabric fibers into the sizing agent for impregnation coating, after staying for 30 seconds, then dry at 120 °C hot air for 5 minutes to form a uniform sizing layer, and obtain the sized aramid fibers, aramid colored filaments and aramid woven fabrics.

[0163] S2. Cut the aramid colored filament unidirectional prepreg into short fiber bundles, evenly sprinkle the short fiber bundles on the aramid fiber unidirectional prepreg, and then obtain the forged texture aramid fiber prepreg through pressing;

[0164] The length of the short fiber bundles is 20 mm; the spreading thickness of the short fiber bundles on the aramid fiber unidirectional prepreg is 0.5 mm - 1.0 mm;

[0165] The pressing conditions are: temperature 150 °C, pressure 1.0 MPa, and time 120 min.

[0166] S3. Lay the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, then lay the release film, the breather felt, and the vacuum bag in sequence, and press in the flame-retardant epoxy resin by vacuum pumping to obtain a composite material; the side of the forged texture aramid fiber prepreg with short-cut fiber bundles is in contact with the mold cavity surface;

[0167] S4. Heat and press the mold with the composite material laid in step S3 as a whole to achieve curing and forming to obtain the forged texture aramid sheet molding compound;

[0168] The dosage of the flame-retardant epoxy resin accounts for 36% of the total mass of the forged texture aramid sheet molding compound;

[0169] During the curing and forming process, the injection pressure is 0.3 MPa; the heating is gradient heating, and the gradient heating process is: from room temperature, at a heating rate of 5°C / min, heat up to 100°C, and then keep warm for 30 min; then continue to heat up to 145°C at a heating rate of 5°C / min and keep warm for 120 min.

[0170] Perform performance tests on the forged texture aramid sheet molding compounds prepared in the above examples and comparative examples, and the specific results are shown in Table 1 below.

[0171] Table 1 Performance test results of the forged texture aramid sheet molding compound

[0172]

[0173] It can be seen from the above table data that: the forged texture aramid sheet molding compounds prepared by the preparation method described in the present invention in Examples 1 - 3 have more excellent impact resistance, and the surface color is diversified, with rich colors and better aesthetics; at the same time, they have good flame-retardant performance, strong interlayer bonding force, and excellent mechanical properties.

[0174] It can be seen from the comparison of the results of Comparative Example 1 and Example 1 that: if the aramid woven fabric prepreg is not added when preparing the forged texture aramid sheet molding compound, during the impact process, the aramid unidirectional prepreg cannot evenly disperse the impact stress in all directions, and the higher modulus of the aramid unidirectional prepreg makes it more likely to undergo impact damage.

[0175] It can be seen from the comparison of the results between Comparative Example 2 and Example 1 that: when preparing the forged-pattern aramid sheet molding compound, if the aramid colored fiber unidirectional prepreg is replaced with the forged-pattern carbon fiber prepreg, the surface color of the forged-pattern aramid sheet molding compound product is single, with only black forged patterns, while the surface color of the forged-pattern aramid fiber sheet molding compound prepared with aramid colored fibers is diversified, with rich colors and better aesthetics. In addition, since a large amount of carbon fiber is used in this sheet molding compound, the impact resistance of the molding compound is reduced, but due to the addition of carbon fiber, the mechanical properties of the aramid sheet molding compound are greatly improved.

[0176] It can be seen from the comparison of the results between Comparative Example 3 and Example 1 that: when preparing the forged-pattern aramid sheet molding compound, if the flame-retardant epoxy resin is replaced with a conventional resin, the flame-retardant performance of the forged-pattern aramid sheet molding compound decreases significantly. The conventional resin is more likely to catch fire when encountering fire, while the flame-retardant epoxy resin is not easy to burn when encountering fire and self-extinguishes when removed from the fire.

[0177] It can be seen from the comparison of the results between Comparative Example 4 and Example 1 that: when preparing the forged-pattern aramid sheet molding compound, when the surfaces of aramid fibers, aramid colored fibers, and aramid woven fabrics are not treated with sizing and activation, the obtained forged-pattern sheet molding compound is prone to delamination when bent. This is because the surface of the aramid fibers without activation treatment is smooth and inert, and the interfacial bonding ability with the matrix resin is poor. It is difficult for the matrix resin to effectively bond to the fiber surface. Under external force, interface failure is more likely to occur between the aramid fibers and the matrix resin and between the aramid prepreg layers, making the prepared sheet molding compound more prone to delamination under external force and reducing its mechanical properties.

[0178] It can be seen from the comparison of the results between Comparative Example 5 and Example 1 that: when preparing the forged-pattern aramid sheet molding compound, if the sizing agent is replaced with a conventional waterborne polyurethane resin, the mechanical properties of the forged-pattern aramid sheet molding compound decrease significantly and delamination is likely to occur. However, the sizing agent used in the present invention contains water-soluble polyamide resin, which is more conducive to improving the interlayer bonding strength and the mechanical properties of the final product. Because the polyethylene glycol segment and polyetheramine D400 in the molecule of the water-soluble polyamide resin enhance the polarity matching and wettability with the epoxy resin, and the molecular structure of the water-soluble polyamide resin is similar to that of the aramid fiber, which also enhances the polarity matching and wettability with the aramid fiber. In addition, during high-temperature curing, the Tg of the polyamide > 180 °C (significantly higher than the Tg of the polyurethane), avoiding interface slippage and increasing the interlaminar shear strength.

[0179] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0180] For those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. A forged aramid sheet molding compound, characterized in that: The forged texture aramid sheet molding compound comprises aramid colored silk unidirectional prepreg, aramid fiber unidirectional prepreg, aramid woven cloth prepreg and flame retardant epoxy resin; Aramid colored yarn, aramid fiber and aramid woven fabric are sizing treated respectively, and then impregnated with flame retardant epoxy resin to obtain the aramid colored yarn unidirectional prepreg, aramid fiber unidirectional prepreg and aramid woven fabric prepreg; The sizing agent used in the sizing treatment includes a water-soluble polyamide resin prepared by polymerizing α,ω-dicarboxyl polyethylene glycol and polyether amine.

2. The forged aramid sheet molding compound according to claim 1, characterized in that: The width of the aramid colored yarn unidirectional prepreg is 15-20 mm; The aramid colored yarn unidirectional prepreg is composed of one or more colors of three primary colors, namely red, yellow and blue, and colors mixed by the three primary colors.

3. The forged aramid sheet molding compound according to claim 1, characterized in that: The aramid fiber unidirectional prepreg is made of primary color aramid fiber unidirectional tape impregnated with flame retardant epoxy resin; The aramid woven fabric prepreg is prepared by sizing and impregnating one or more of aramid plain fabric and aramid twill fabric with flame retardant epoxy resin.

4. The forged aramid sheet molding compound according to claim 1, characterized in that: The preparation method of the water-soluble polyamide resin comprises the following steps: adding pyridine, triphenyl phosphite, calcium chloride and lithium chloride into N-methylpyrrolidone, stirring to completely dissolve the calcium chloride and lithium chloride, then adding polyetheramine and α,ω-dicarboxyl polyethylene glycol into the system, heating and stirring until the system becomes completely clear, heating under the protection of inert gas to carry out polymerization reaction, and obtaining the water-soluble polyamide resin through post-treatment after the reaction is completed.

5. The forged aramid sheet molding compound according to claim 1, characterized in that: The sizing agent is prepared by dissolving a water-soluble polyamide resin in water to prepare an aqueous solution with a concentration of 5-10wt%, and then adding a wetting agent in an amount of 0.1-0.2% by weight of the aqueous solution to the aqueous solution.

6. A method for preparing a forged aramid sheet molding compound according to any one of claims 1 to 5, characterized in that: The preparation method is: S1, sizing aramid fiber, aramid colored yarn and aramid woven fabric, and then respectively impregnating them with flame retardant epoxy resin to obtain aramid colored yarn unidirectional prepreg, aramid fiber unidirectional prepreg and aramid woven fabric prepreg; S2, cutting the aramid colored yarn unidirectional prepreg into chopped fiber bundles, evenly spreading the chopped fiber bundles on the aramid fiber unidirectional prepreg, and then pressing to obtain a forged textured aramid fiber prepreg; S3, laying the forged texture aramid fiber prepreg and the aramid woven fabric prepreg on the mold cavity surface in sequence, and then laying the isolation film, breathable felt, and vacuum bag in sequence, and pressing in the flame-retardant epoxy resin by vacuuming to obtain a composite material; S4, heating and pressurizing the entire mold after the composite material is laid in step S3 to achieve curing and molding to obtain the forged aramid sheet molding compound.

7. The method for preparing a forged aramid sheet molding compound according to claim 6, characterized in that: In step S2, the length of the chopped fiber bundle is 20 mm-40 mm; the thickness of the chopped fiber bundle spread on the aramid fiber unidirectional prepreg is 0.5 mm-1.5 mm.

8. The method for preparing a forged aramid sheet molding compound according to claim 6, characterized in that: In step S2, the pressing conditions are: temperature 145-155°C, pressure 1.0-2.0 MPa, and time 60-120 min.

9. The method for preparing a forged aramid sheet molding compound according to claim 6, characterized in that: The amount of the flame retardant epoxy resin used accounts for 30%-40% of the total mass of the forged aramid sheet molding compound.

10. The method for preparing a forged aramid sheet molding compound according to claim 6, characterized in that: In step S4, during the curing process, the injection pressure is 0.1-1.0 MPa; the heating is gradient heating, and the gradient heating process is: from room temperature, at a heating rate of 4-5°C / min, the temperature is increased to 100±2°C, and then kept warm for 20-30min; then at a heating rate of 4-5°C / min, the temperature is continued to be increased to 145±5°C, and kept warm for 100-120min.

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