Sizing agent coated short carbon fiber composite material and preparation method thereof

Abstract

The invention discloses a sizing agent coated short carbon fiber composite material and a preparation method thereof, and the preparation method comprises the following steps: firstly, preparing a hydrophilic sizing agent, dipping carbon fibers in the sizing agent, drying, cutting into short carbon fibers, adding into a solvent containing a binder, stirring into uniform slurry, and drying to obtain the sizing agent coated short carbon fiber composite material. The slurry is evenly sprayed to a conveying belt with a filter screen, the conveying belt passes through two extrusion rollers, the interior of one roller is vacuumized, and then a wet felt with a certain thickness is formed through drying. The wet felt can be cut into any size and placed in a corresponding mold in a laminated mode, and pressure is applied while heating curing forming is conducted. The carbon fibers coated with the hydrophilic sizing agent can be uniformly dispersed in water, use of an organic suspending agent is avoided, the slurry consistency is good, fiber distribution anisotropy and mechanical properties in the product are excellent, the product stability is good, the cost is low, environmental friendliness is achieved, fiber and resin are uniformly distributed, interlayer combination is tight, and the fiber length is adjustable.

Description

Technical Field

[0001] The invention relates to the technical field of heat insulation material preparation, and in particular to a method for preparing a sizing agent coated short-cut carbon fiber composite material. Background Art

[0002] Carbon fiber has been attracting much attention since its birth. With the advancement of science and technology, the application of carbon fiber has become increasingly widespread. Carbon fiber is rarely used alone due to its own brittleness. It is generally used as a reinforcing material for composite materials. Depending on the application field, carbon fiber can be compounded with different matrix materials. Through different composite treatments and molding processing methods, carbon fiber composite materials with outstanding performance in a certain aspect can be designed and prepared. Carbon fiber reinforced resin-based composite materials are the most widely used. They not only have various excellent properties, but also have diversified advantages in the selection of molding processes. At present, the prior art such as publication number CN202111675754.3 discloses a carbon fiber dispersion and a preparation method thereof, a gas diffusion layer and a fuel cell: a preparation method of a carbon fiber dispersion, mixing a suspending agent and water and then irradiating to obtain a suspension solution treated with radiation; the suspending agent is selected from at least one of hydroxypropyl methylcellulose, cyanoethyl cellulose and carboxymethyl hydroxyethyl cellulose; the dispersant solution and carbon fiber are mixed to obtain a carbon fiber dispersion. Carbon fibers are mostly dispersed using organic suspending agents. The use of organic suspending agents may cause energy consumption and environmental pollution, and expand their dispersion technology to reduce the use of organic solvents. Summary of the invention

[0003] Technical problem to be solved: The purpose of the present invention is to provide a sizing agent coated chopped carbon fiber composite material and a preparation method thereof, so as to solve the problems of uneven distribution of chopped carbon fibers, large amount of organic suspending agents, energy consumption and environmental pollution in the current preparation technology of carbon fiber thermal insulation materials.

[0004] Technical solution: The present invention provides a sizing agent coated short-cut carbon fiber composite material and a preparation method thereof, the method comprising the following steps: Step 1, immersing the carbon fiber in the prepared hydrophilic sizing agent, coating the surface of the carbon fiber with the sizing agent, drying the carbon fiber, and then cutting the carbon fiber into chopped carbon fiber; Step 2: adding the chopped carbon fibers coated with a hydrophilic sizing agent to a solvent containing a binder and stirring the mixture into a uniform slurry; Step 3: Spray the slurry evenly onto a conveyor belt with a filter screen. The conveyor belt passes through two squeezing rollers, one of which is vacuumed, and then dried to form a wet felt of a certain thickness. Step 4, the wet felt is cut into any size, stacked and placed in a corresponding mold, and heated and cured while applying pressure. Further, the preparation method of the hydrophilic sizing agent in step 1 is as follows: first, the acrylic emulsion and water are mixed and stirred, and then polyethylene glycol, sodium dodecyl sulfate, polydimethylsiloxane, polyoxyethylene polyoxypropylene pentaerythritol ether, and polyvinyl alcohol are added and stirred for reaction, and then fillers melamine and graphene oxide are added to obtain a hydrophilic sizing agent. Furthermore, in the hydrophilic sizing agent, the mass ratio of acrylic emulsion, water, polyethylene glycol, sodium dodecyl sulfate, polydimethylsiloxane, polyoxyethylene polyoxypropylene pentaerythritol ether, polyvinyl alcohol, melamine and graphene oxide is: 80-90: 8-10: 3-4: 1-2: 0.01-0.03: 0.04-0.06: 0.1-0.3: 1-5: 1-2. Furthermore, in step 2, the chopped carbon fibers are immersed in the hydrophilic sizing agent for 0.5-40 min, and the thickness of the hydrophilic sizing agent coated on the surface of the chopped carbon fibers is 20 nm. Furthermore, the carbon fiber in step 2 includes one or more of polyacrylonitrile-based carbon fiber, viscose-based carbon fiber, and asphalt-based carbon fiber; the drying temperature is 60-80° C., and the drying time is 60-90 min; and the length of the chopped carbon fiber is 5-30 mm. Furthermore, in step 2, the binder is one or more of a water-based epoxy resin binder, a water-soluble phenolic resin binder, a water-soluble polyimide binder, a water-soluble urea-formaldehyde resin binder and a water-soluble acrylic resin binder; and the solvent is water or a mixture of water and ethanol. Furthermore, in step 2, the mass ratio of carbon fiber, hydrophilic sizing agent, binder and solvent is 50-100: 1-10: 100-200: 500-1000. Furthermore, in the process of stirring into a uniform slurry in step 3, the stirring speed is 1000-5000 rpm, and the stirring time is 10-120 min. Furthermore, in step 3, the vacuum degree of the vacuum extraction is -0.05 to -0.1 MPa, the drying temperature is 80 to 120° C., the drying time is 60 to 120 min, and the thickness of the wet felt is 1 to 5 mm. Furthermore, in step 4, the pressure applied is 0.5-5 MPa, the heating temperature is 80-150° C., and the heating time is 100-300 min; the size of the mold is adjustable; and the wet felt can be placed in the mold through Z-type stacking for compression molding. Beneficial effects: The sizing agent coated short-cut carbon fiber composite material and the preparation method thereof provided by the present invention have the following advantages: 1. The hydrophilic sizing agent provided by the present invention increases the surface active groups of carbon fibers, improves the bonding force between carbon fibers and resin, and plays a role in reinforcing the interface of carbon fibers, thereby improving the mechanical properties of composite materials; in addition, the hydrophilic sizing agent has good adhesion properties, can greatly shorten the impregnation time, and improve production efficiency. 2. The present invention introduces fillers with excellent water resistance, high temperature resistance and excellent flame retardancy, namely melamine and graphene oxide, into the sizing agent, thereby enhancing the thermal insulation and flame retardancy of the prepared short-cut carbon fiber composite material and meeting actual use requirements. 3. The carbon fiber coated with the hydrophilic sizing agent can be evenly dispersed in water, avoiding the use of organic suspending agents, with good slurry consistency, anisotropic fiber distribution in the product, excellent mechanical properties, good product stability, low cost, environmental friendliness, and even distribution of fibers and resins, tight interlayer bonding, and adjustable fiber length. The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a schematic diagram of the structure of chopped carbon fiber with a hydrophilic sizing agent coated on the surface. Figure 2 It is a process flow chart of wet felt preparation. DETAILED DESCRIPTION The following introduces several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text. Example 1 A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing polyacrylonitrile-based carbon fiber (50 parts) in the prepared hydrophilic sizing agent (1 part) for 0.5 min, coating the surface with a sizing agent with a thickness of 20 nm, drying at 60° C. for 60 min, and then cutting it into 5 mm short carbon fibers; Step 2: adding the chopped carbon fibers coated with a hydrophilic sizing agent to water (500 parts) containing a water-soluble phenolic resin binder (100 parts), and stirring at 1000 rpm for 10 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.05MPa, and then dried at 80°C for 60 minutes to form a wet felt with a thickness of 1mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 80°C for 100 minutes while applying a pressure of 0.5 MPa to solidify the mold. Wherein, the preparation of the hydrophilic sizing agent in step 1 comprises the following steps: Step 11, adding acrylic emulsion (80 parts) into water (8 parts) and stirring at 4000 rpm for 60 min, then adding polyethylene glycol (3 parts), sodium dodecyl sulfate (1 part), polydimethylsiloxane (0.01 parts), polyoxyethylene polyoxypropylene pentaerythritol ether (0.04 parts), polyvinyl alcohol (0.1 parts) and stirring at 5000 rpm for 60 min; Step 12: Add melamine (1 part) and graphene oxide (1 part) and stir at 5000 rpm for 60 min to prepare a hydrophilic sizing agent. Example 2 A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing the viscose-based carbon fiber (100 parts) in the prepared hydrophilic sizing agent (10 parts) for 40 minutes, coating the surface with a sizing agent with a thickness of 200 nm, drying at 80°C for 90 minutes, and then cutting it into 30 mm short carbon fibers; Step 2, adding the short carbon fibers coated with the hydrophilic sizing agent to water / ethanol (1000 parts) containing an aqueous epoxy resin binder (200 parts), stirring at 5000 rpm for 120 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.1 MPa, and then dried at 120°C for 120 minutes to form a wet felt with a thickness of 5 mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 150° C. for 300 min while applying a pressure of 5 MPa to solidify the mold. Wherein, the preparation of the hydrophilic sizing agent in step 1 comprises the following steps: Step 11, adding acrylic emulsion (90 parts) into water (10 parts) and stirring at 4000 rpm for 60 min, then adding polyethylene glycol (4 parts), sodium dodecyl sulfate (2 parts), polydimethylsiloxane (0.03 parts), polyoxyethylene polyoxypropylene pentaerythritol ether (0.06 parts), polyvinyl alcohol (0.3 parts) and stirring at 5000 rpm for 60 min; Step 12: Add melamine (5 parts) and graphene oxide (2 parts) and stir at 5000 rpm for 60 minutes to prepare a hydrophilic sizing agent. Example 3 A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing asphalt-based carbon fiber (60 parts) in the prepared hydrophilic sizing agent (2 parts) for 5 minutes, coating the surface with a sizing agent with a thickness of 25 nm, drying at 60° C. for 70 minutes, and then cutting it into 8 mm short carbon fibers; Step 2: Add the chopped carbon fibers coated with a hydrophilic sizing agent to ethanol (550 parts) containing a water-soluble polyimide binder (120 parts), and stir at 1200 rpm for 15 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.05MPa, and then dried at 80°C for 60 minutes to form a wet felt with a thickness of 2mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 80° C. for 120 min while applying a pressure of 0.5 MPa to solidify the mold. Wherein, the preparation of the hydrophilic sizing agent in step 1 comprises the following steps: Step 11, adding acrylic emulsion (85 parts) into water (8 parts) and stirring at 4000 rpm for 60 min, then adding polyethylene glycol (4 parts), sodium dodecyl sulfate (1 part), polydimethylsiloxane (0.01 parts), polyoxyethylene polyoxypropylene pentaerythritol ether (0.05 parts), and polyvinyl alcohol (0.2 parts) and stirring at 5000 rpm for 60 min; Step 12: Add melamine (3 parts) and graphene oxide (1 part) and stir at 6000 rpm for 65 minutes to prepare a hydrophilic sizing agent. Example 4 A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing polyacrylonitrile-based carbon fiber (75 parts) in the prepared hydrophilic sizing agent (1 part) for 0.5 min, coating the surface with a sizing agent with a thickness of 50 nm, drying at 65° C. for 70 min, and then cutting it into 5 mm short carbon fibers; Step 2: Add the chopped carbon fibers coated with a hydrophilic sizing agent to water (800 parts) containing a water-soluble urea-formaldehyde resin binder (100 parts), and stir at 1000 rpm for 10 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.05MPa, and then dried at 80°C for 60 minutes to form a wet felt with a thickness of 1mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 80°C for 100 minutes while applying a pressure of 0.4 MPa to solidify the mold. Wherein, the preparation of the hydrophilic sizing agent in step 1 comprises the following steps: Step 11, adding acrylic emulsion (85 parts) into water (9 parts) and stirring at 4000 rpm for 60 min, then adding polyethylene glycol (3 parts), sodium dodecyl sulfate (2 parts), polydimethylsiloxane (0.01 parts), polyoxyethylene polyoxypropylene pentaerythritol ether (0.05 parts), and polyvinyl alcohol (0.1 parts) and stirring at 5000 rpm for 60 min; Step 12: Add melamine (4 parts) and graphene oxide (1 part) and stir at 5000 rpm for 70 minutes to prepare a hydrophilic sizing agent. Example 5 A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing viscose-based carbon fiber (80 parts) in the prepared hydrophilic sizing agent (5 parts) for 10 minutes, coating the surface with a sizing agent with a thickness of 20 nm, drying at 60° C. for 60 minutes, and then cutting it into 5 mm short carbon fibers; Step 2: adding the chopped carbon fibers coated with a hydrophilic sizing agent to water (900 parts) containing a water-soluble acrylic resin binder (160 parts), and stirring at 1000 rpm for 90 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.05MPa, and then dried at 80°C for 60 minutes to form a wet felt with a thickness of 1mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 100° C. for 100 minutes while applying a pressure of 4 MPa to solidify the mold. Wherein, the preparation of the hydrophilic sizing agent in step 1 comprises the following steps: Step 11, adding acrylic emulsion (88 parts) into water (10 parts) and stirring at 3500 rpm for 60 min, then adding polyethylene glycol (4 parts), sodium dodecyl sulfate (1 part), polydimethylsiloxane (0.02 parts), polyoxyethylene polyoxypropylene pentaerythritol ether (0.05 parts), polyvinyl alcohol (0.2 parts) and stirring at 4500 rpm for 60 min; Step 12: Add melamine (3 parts) and graphene oxide (2 parts) and stir at 5500 rpm for 60 min to prepare a hydrophilic sizing agent. Comparative Example 1 The difference between this comparative example and Example 5 is that a sizing agent in the prior art is used, which is as follows: A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing viscose-based carbon fiber (80 parts) in a hydrophilic lignin-based sizing agent (5 parts) for 10 minutes, coating the surface with a sizing agent with a thickness of 20 nm, drying at 60° C. for 60 minutes, and then cutting it into 5 mm short carbon fibers; Step 2: adding the chopped carbon fibers coated with a hydrophilic sizing agent to water (900 parts) containing a water-soluble acrylic resin binder (160 parts), and stirring at 1000 rpm for 90 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.05MPa, and then dried at 80°C for 60 minutes to form a wet felt with a thickness of 1mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 100° C. for 100 minutes while applying a pressure of 4 MPa to solidify the mold. Wherein, the preparation of the hydrophilic sizing agent in step 1 comprises the following steps: Step 11, adding acrylic emulsion (88 parts) into water (10 parts) and stirring at 3500 rpm for 60 min, then adding polyethylene glycol (4 parts), sodium dodecyl sulfate (1 part), polydimethylsiloxane (0.02 parts), polyoxyethylene polyoxypropylene pentaerythritol ether (0.05 parts), polyvinyl alcohol (0.2 parts) and stirring at 4500 rpm for 60 min; Step 12: Add melamine (3 parts) and graphene oxide (2 parts) and stir at 5500 rpm for 60 min to prepare a hydrophilic sizing agent. Comparative Example 2 The difference between this comparative example and Example 5 is that a sizing agent in the prior art is used, which is as follows: A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing viscose-based carbon fiber (80 parts) in the prepared sizing agent (5 parts) for 10 minutes, coating the surface with a sizing agent with a thickness of 20 nm, drying at 60° C. for 60 minutes, and then cutting it into 5 mm short carbon fibers; Step 2, adding the chopped carbon fibers coated with a sizing agent to a water-soluble acrylic resin binder (160 parts), and stirring at 1000 rpm for 90 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.05MPa, and then dried at 80°C for 60 minutes to form a wet felt with a thickness of 1mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 100° C. for 100 minutes while applying a pressure of 4 MPa to solidify the mold. Wherein, the preparation of the sizing agent in step 1 comprises the following steps: Step 1: prepare composite epoxy resin by mixing KD-213, YD-128 epoxy resin and acetone in a mass ratio of 0.8:1:1.5; Step 2: react oleic acid amide with YD-128 epoxy resin at 90°C for 60 minutes, then uniformly mix with the composite epoxy resin, slowly add water and stir to obtain a modified epoxy resin sizing agent. Comparative Example 3 The difference between this comparative example and Example 5 is that a sizing agent in the prior art is used, which is as follows: A method for preparing a sizing agent coated short-cut carbon fiber composite material comprises the following steps: Step 1, immersing viscose-based carbon fiber (80 parts) in vinyl ester resin sizing agent (5 parts) for 10 minutes, coating the surface with sizing agent with a thickness of 20 nm, drying at 60° C. for 60 minutes, and then cutting it into 5 mm short carbon fiber; Step 2, adding the chopped carbon fibers coated with a sizing agent to water (900 parts) containing a water-soluble acrylic resin binder (160 parts), and stirring at 1000 rpm for 90 minutes to obtain a uniform slurry; Step 3, spray the slurry evenly onto a conveyor belt with a filter screen, and the conveyor belt passes through two extrusion rollers, one of which is vacuumed to -0.05MPa, and then dried at 80°C for 60 minutes to form a wet felt with a thickness of 1mm; Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated at 100° C. for 100 minutes while applying a pressure of 4 MPa to solidify the mold. Performance Testing The bending strength and interlaminar shear strength of the samples prepared in Examples 1 to 5 of the present invention and Comparative Examples 1 to 3 were tested. The test results are shown in Table 1. Table 1 Flexural strength and interlaminar shear strength of composite materials prepared in various embodiments and comparative examples sample Bending strength(MPa) Interlaminar shear strength (MPa) Example 1 252.4 62.4 Example 2 242.5 58.6 Example 3 268.3 65.8 Example 4 256.6 55.2 Example 5 244.8 57.6 Comparative Example 1 182.5 43.9 Comparative Example 2 197.3 42.7 Comparative Example 3 189.1 41.2 As can be seen from Table 1, Example 1 uses the new sizing agent prepared by the present invention to arrange short-cut carbon fibers to form a sizing agent-coated short-cut carbon fiber composite material. Compared with the comparative example 1, the mechanical properties of the composite material prepared by arranging short-cut carbon fibers with the sizing agent in the prior art are greatly improved, and the bending strength is improved by 38.3%, and the interlaminar shear strength is improved by 42.1%. This shows that the new hydrophilic sizing agent prepared by the present invention is superior to the prior art in improving the mechanical properties of the composite material. The above describes in detail the preferred specific embodiments of the present invention. It should be understood that the common technology in this field can make many modifications and changes based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by technicians in this technical field through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a sizing agent coated short-cut carbon fiber composite material, characterized in that: The method comprises the following steps: Step 1, immersing the carbon fiber in the prepared hydrophilic sizing agent, coating the surface of the carbon fiber with the sizing agent, drying the carbon fiber, and then cutting the carbon fiber into chopped carbon fiber; Step 2: adding the chopped carbon fibers coated with a hydrophilic sizing agent to a solvent containing a binder and stirring the mixture into a uniform slurry; Step 3: Spray the slurry evenly onto a conveyor belt with a filter screen. The conveyor belt passes through two squeezing rollers, one of which is vacuumed, and then dried to form a wet felt of a certain thickness. Step 4: The wet felt is cut into any size, stacked and placed in a corresponding mold, and heated and cured while applying pressure.

2. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: The preparation method of the hydrophilic sizing agent in step 1 is as follows: first, the acrylic emulsion and water are mixed and stirred, and then polyethylene glycol, sodium dodecyl sulfate, polydimethylsiloxane, polyoxyethylene polyoxypropylene pentaerythritol ether, and polyvinyl alcohol are added and stirred for reaction, and then filler melamine and graphene oxide are added to obtain the hydrophilic sizing agent.

3. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 2, characterized in that: In the hydrophilic sizing agent, the mass ratio of acrylic emulsion, water, polyethylene glycol, sodium dodecyl sulfate, polydimethylsiloxane, polyoxyethylene polyoxypropylene pentaerythritol ether, polyvinyl alcohol, melamine and graphene oxide is: 80-90: 8-10: 3-4: 1-2: 0.01-0.03: 0.04-0.06: 0.1-0.3: 1-5: 1-2.

4. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: In the step 2, the chopped carbon fibers are immersed in the hydrophilic sizing agent for 0.5-40 minutes, and the thickness of the hydrophilic sizing agent coated on the surface of the chopped carbon fibers is 20-200 nm.

5. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: The carbon fiber in step 2 includes one or more of polyacrylonitrile-based carbon fiber, viscose-based carbon fiber, and asphalt-based carbon fiber; the drying temperature is 60-80° C., and the drying time is 60-90 min; and the length of the chopped carbon fiber is 5-30 mm.

6. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: In step 2, the binder is one or more of a water-based epoxy resin binder, a water-soluble phenolic resin binder, a water-soluble polyimide binder, a water-soluble urea-formaldehyde resin binder and a water-soluble acrylic resin binder; and the solvent is water or a mixture of water and ethanol.

7. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: In the step 2, the mass ratio of carbon fiber, hydrophilic sizing agent, binder and solvent is 50-100: 1-10: 100-200: 500-1000.

8. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: In step 3, the stirring speed during the stirring into a uniform slurry is 1000-5000 rpm, and the stirring time is 10-120 min.

9. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: The vacuum degree of the vacuum pumping in the step 3 is -0.05 to -0.1 MPa, the drying temperature is 80 to 120° C., the drying time is 60 to 120 min, and the wet felt thickness is 1 to 5 mm.

10. The method for preparing a sizing agent coated short-cut carbon fiber composite material according to claim 1, characterized in that: In step 5, the applied pressure is 0.5-5 MPa, the heating temperature is 80-150° C., and the heating time is 100-300 min.

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