Preparation Method and Application of Short Inorganic Fiber Hybrid Mesh and Composite Carbon Fiber Tape

Abstract

The present invention relates to a preparation method and application of a short inorganic fiber hybrid mesh yarn and a composite carbon fiber tape, belonging to the technical field of polymer matrix composites. The preparation method includes the following steps: impregnating a short inorganic fiber mesh yarn in a suspension of a thermoplastic resin powder mixture, drying, heat setting and naturally cooling to obtain a short inorganic fiber hybrid mesh yarn covered with thermoplastic resin particles; after spraying a sizing agent with a certain areal density on both sides of a unidirectional carbon fiber tape, laying the hybrid mesh yarn on the surface of the unidirectional carbon fiber tape, and completing the composite after preheating, hot pressing and natural cooling. This process method is easy to realize the continuous production of the composite carbon fiber tape and has a low cost. The carbon fiber composite material prepared by the composite carbon fiber tape through liquid molding has significantly improved interlayer toughness.

Description

Technical Field

[0001] The present invention belongs to the field of polymer matrix composites, and particularly relates to a preparation method and application of a short inorganic fiber hybrid mesh yarn and a composite carbon fiber tape, which are used for preparing high-toughness carbon fiber composites through an automated fiber placement and liquid molding process. Background Art

[0002] Carbon fiber reinforced thermosetting resin matrix composites (hereinafter referred to as carbon fiber composites) have been widely used in the fields of aerospace, rail transit, ship shipping, and vehicle engineering due to their high specific strength, high specific modulus, good chemical stability, and strong designability. Compared with the traditional autoclave molding of prepregs, the carbon fiber composites prepared by the combination of automated fiber placement of composite carbon fiber tapes and liquid molding process have lower comprehensive production costs and higher production efficiency under the condition of comparable performance, so it has become an important development direction of the carbon fiber composite preparation process.

[0003] In practical applications, the composite carbon fiber tape material is usually a composite structure formed by combining unidirectional carbon fibers and a surface toughening layer. The main function of the surface toughening layer is to improve the delamination resistance of carbon fiber composites, because the highly cross-linked thermosetting resin in the interlayer region of carbon fiber composites has intrinsic brittleness and is prone to delamination damage under low-velocity impact and cyclic loading, leading to structural failure. However, the introduction of the surface toughening layer also needs to consider its influence on the liquid molding process performance of the composite material, other mechanical properties of the composite material, and the automated fiber placement process performance of the composite carbon fiber tape.

[0004] Chinese Patent CN 110757908A (publication date: February 7, 2020) discloses a method for preparing carbon fiber composites by synergistic toughening with a porous nanofiber membrane. In this method, a nylon 66 nanofiber membrane with carboxylated carbon nanotubes on the surface is placed between the plies of the carbon fiber composite. This method does not require modification of the thermosetting resin and improves the interlayer toughness of the carbon fiber composite by using a nanoscale toughening mechanism. However, the preparation cost of the nanofiber membrane is relatively high. Using only thermoplastic nanofibers for toughening may affect the in-plane mechanical properties of the carbon fiber composite, and the low mechanical strength of the nanofiber membrane may affect the placement performance of the composite carbon fiber tape.

[0005] Chinese Patent CN 112677602A (published on April 20, 2021) discloses a method for preparing an interlayer toughened carbon fiber composite using a carbon material aerogel and a thermoplastic resin. This method composes the carbon material aerogel and the thermoplastic resin to obtain a toughened layer and lays it between the plies of the carbon fiber composite. This method can significantly improve the interlayer toughness of the carbon fiber composite and maintain its in-plane mechanical properties. However, the preparation efficiency of this method is relatively low. The pore structure of the aerogel may affect the perfusion of the liquid molding resin, and a single inorganic toughened layer is difficult to provide the interlayer bonding force required for the automatic placement of composite carbon fiber tapes.

[0006] Although the above-mentioned technologies respectively use thermoplastic toughening materials and inorganic toughening materials to improve the interlayer toughness of carbon fiber composites, there are limitations to varying degrees in terms of preparation cost, preparation efficiency, the process performance of composite material liquid molding, and maintaining the in-plane mechanical properties of the composite material, and it is difficult to meet the regulation requirements of the process performance of composite carbon fiber tape automatic placement. Summary of the Invention

[0007] The present invention aims to solve the deficiencies of the prior art and provides a preparation method for a short inorganic fiber hybrid mesh and a composite carbon fiber tape. This composite carbon fiber tape can be used to prepare a high-toughness carbon fiber composite through automatic placement and liquid molding processes. It is necessary to have a toughening material that can be prepared on a large scale at low cost, has good liquid molding process performance, and does not affect the in-plane mechanical properties of the carbon fiber composite. At the same time, it also needs to meet the controllability requirements of the automatic placement of the composite carbon fiber tape.

[0008] A preparation method for a short inorganic fiber hybrid mesh and a composite carbon fiber tape includes the following steps:

[0009] (1) Configure a thermoplastic resin powder mixture by mixing a thermoplastic resin, a sizing agent, and a surfactant in a certain proportion;

[0010] (2) Configure the thermoplastic resin powder mixture in step (1) into a suspension with a mass fraction of 20 - 60%;

[0011] (3) Immerse the short inorganic fiber mesh in the suspension in step (2) for 1 - 10 minutes to obtain a short inorganic fiber mesh containing the thermoplastic resin powder mixture;

[0012] (4) Dry, heat-set, and naturally cool the short inorganic fiber mesh treated in step (3) to obtain a short inorganic fiber hybrid mesh;

[0013] (5) Introduce a sizing agent on both sides of the unidirectional carbon fiber tape, lay the short inorganic fiber hybrid mesh in step (4) on both sides of the unidirectional carbon fiber tape, and after preheating, pressurizing, and natural cooling, obtain a composite carbon fiber tape with a short inorganic fiber hybrid mesh.

[0014] Preferably, the thermoplastic resin in step (1) of the present invention is at least one of carboxyl-terminated sulfonated polyarylether sulfone, biphenyl-containing polyarylether sulfone, fluorosulfonated bis-triptycene-type polyarylether sulfone, and tert-butyl-containing polyarylether sulfone. The particle size distribution of the thermoplastic resin is 30 - 100 μm, and the mass fraction in the thermoplastic resin powder mixture is 40 - 60%.

[0015] Preferably, the sizing agent in steps (1) and (5) of the present invention is an uncured solid epoxy resin, including at least one of bisphenol A epoxy resins E44, E20, and E12. The particle size distribution of the sizing agent is 50 - 150 μm, and the mass fraction in the thermoplastic resin powder mixture is 30 - 50%.

[0016] Preferably, the surfactant in step (1) of the present invention is a non-ionic surfactant, and the mass fraction in the thermoplastic resin powder mixture is 5 - 10%.

[0017] Preferably, the areal density of the short inorganic fiber mesh in step (3) of the present invention is 4 - 6 g / m 2 , which is composed of basalt fiber or alumina fiber; the length range of the short inorganic fiber is 4 - 10 mm, and the diameter range of the short inorganic fiber is 3 - 15 μm.

[0018] Preferably, the drying and heat setting in step (4) of the present invention are achieved by an infrared heater. The drying temperature is 40 - 120 °C, and the heat setting temperature is 150 - 250 °C.

[0019] Preferably, in step (5) of the present invention, the method for introducing the sizing agent is electrostatic spraying. The high voltage range of the electrostatic spraying is 30 - 80 kV, the atomizing pressure range is 0.1 - 0.2 MPa, the flow rate pressure range is 0.1 - 0.8 MPa, the spraying distance range is 100 - 300 mm, and the spraying amount on the carbon fiber surface is 5 - 25 g / m 2 .

[0020] Preferably, in step (5) of the present invention, the preheating process is achieved by an infrared heater, and the heating temperature range is 90 - 180 °C; the pressing process is achieved by a hot pressing wheel set, the temperature range is 80 - 100 °C, and the pressure range is 0.4 - 1.1 MPa.

[0021] A short inorganic fiber hybrid mesh and a composite carbon fiber tape obtained by using the preparation method of the present invention.

[0022] An application of a composite carbon fiber tape obtained by using the preparation method of the present invention in a liquid molding carbon fiber composite material.

[0023] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0024] 1. The short inorganic fiber hybrid gauze involved in the present invention can achieve continuous preparation with low cost and high efficiency;

[0025] 2. The composite carbon fiber tape of the short inorganic fiber hybrid gauze involved in the present invention has good interlayer adhesion during the automatic placement process;

[0026] 3. The composite carbon fiber tape of the short inorganic fiber hybrid gauze involved in the present invention has higher forming efficiency during the liquid molding process;

[0027] 4. The composite carbon fiber tape of the short inorganic fiber hybrid gauze involved in the present invention can prepare a composite material with significantly improved interlayer toughness and basically maintained in-plane mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic structural diagram of the short alumina fiber hybrid gauze prepared in Example 1;

[0029] Figure 2 Microstructure of the composite material prepared from the composite carbon fiber tape in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0031] A preparation method of a short inorganic fiber hybrid gauze and its composite carbon fiber tape includes the following steps:

[0032] (1) A thermoplastic resin powder mixture is prepared by mixing a thermoplastic resin, a sizing agent, and a surfactant in a certain proportion.

[0033] The thermoplastic resin is at least one of carboxyl-terminated sulfonated polyarylether sulfone, biphenyl-containing polyarylether sulfone, fluorosulfonated bis-triptycene-based polyarylether sulfone, and tert-butyl-containing polyarylether sulfone. The particle size distribution of the thermoplastic resin is 30 - 100 μm, and the mass fraction in the thermoplastic resin powder mixture is 40 - 60%. The surfactant is a non-ionic surfactant, and its mass fraction in the thermoplastic resin powder mixture is 5 - 10%.

[0034] (2) The thermoplastic resin powder mixture in step (1) is prepared into a suspension with a mass fraction of 20 - 60%.

[0035] (3) Immerse the short inorganic fiber mesh in the suspension in step (2) for 1 - 10 minutes to obtain a short inorganic fiber mesh containing a thermoplastic resin powder mixture.

[0036] The areal density of the short inorganic fiber mesh is 4 - 6 g / m 2 , which is composed of basalt fibers or alumina fibers; the length range of the short inorganic fibers is 4 - 10 mm, and the diameter range of the short inorganic fibers is 3 - 15 μm.

[0037] (4) Dry, heat - set and naturally cool the short inorganic fiber mesh after being treated in step (3) to obtain a short inorganic fiber hybrid mesh.

[0038] The drying and heat - setting are achieved by an infrared heater. The drying temperature is 40 - 120 °C, and the heat - setting temperature is 150 - 250 °C.

[0039] (5) Apply a sizing agent on both sides of the unidirectional carbon fiber tape, lay the short inorganic fiber hybrid mesh in step (4) on both sides of the unidirectional carbon fiber tape, and after pre - heating, pressing and natural cooling, obtain a composite carbon fiber tape with a short inorganic fiber hybrid mesh.

[0040] The sizing agent is introduced by electrostatic spraying. The high - voltage range of electrostatic spraying is 30 - 80 kV, the atomizing pressure range is 0.1 - 0.2 MPa, the flow - rate pressure range is 0.1 - 0.8 MPa, the spraying distance range is 100 - 300 mm, and the spraying amount on the carbon fiber surface is 5 - 25 g / m 2 . The pre - heating process is achieved by an infrared heater, and the heating temperature range is 90 - 180 °C; the pressing process is achieved by a hot - pressing wheel group, the temperature range is 80 - 100 °C, and the pressure range is 0.4 - 1.1 MPa.

[0041] The sizing agent in steps (1) and (5) of the present invention is an uncured solid epoxy resin, including at least one of bisphenol A epoxy resins E44, E20 and E12. The particle size distribution of the sizing agent is 50 - 150 μm, and the mass fraction in the thermoplastic resin powder mixture is 30 - 50%.

[0042] Example 1

[0043] This example provides a method for preparing a composite carbon fiber tape with a short alumina fiber hybrid mesh covered with terminal - carboxyl sulfonated polyarylether sulfone particles, and the steps are as follows:

[0044] (1) Prepare a thermoplastic resin powder mixture by mixing terminal - carboxyl sulfonated polyarylether sulfone, solid epoxy resin E44 and carboxymethyl cellulose in a mass ratio of 6:3:1;

[0045] (2) Add the thermoplastic resin powder mixture obtained in step (1) to water, and obtain a suspension with a mass fraction of 40% through mechanical stirring;

[0046] (3) Immerse a short alumina fiber mesh with an average fiber length of 4 mm and a surface density of 8 g / m 2 in the suspension obtained in step (2) for 2 minutes to obtain a short alumina fiber mesh containing the thermoplastic resin powder mixture;

[0047] (4) Use an infrared heater to dry and heat-set the mesh obtained in step (3) at 80 °C and 230 °C respectively, and then naturally cool to obtain a short alumina fiber hybrid mesh covered with terminal carboxyl sulfonated polyarylether sulfone particles, and the structure is as Figure 1 shown;

[0048] (5) Introduce 10 g / m 2 of solid epoxy resin E44 powder on both sides of a 24k T800 unidirectional carbon fiber tape by electrostatic spraying. The electrostatic high voltage is 65 kV, the atomization pressure is 0.5 MPa, the flow rate pressure is 0.4 MPa, and the spraying distance is 150 mm;

[0049] (6) Lay the hybrid mesh obtained in step (4) on both sides of the carbon fiber tape obtained in step (5), and use an infrared heater to preheat the hybrid mesh and the carbon fiber tape to 150 °C;

[0050] (7) Hot-press the preheated hybrid mesh and carbon fiber tape in step (6) through a hot-press roller set with a temperature and pressure of 80 °C and 0.4 MPa respectively, and obtain a composite carbon fiber tape with a short alumina fiber hybrid mesh covered with terminal carboxyl sulfonated polyarylether sulfone particles after natural cooling;

[0051] (8) Lay the composite carbon fiber tape with a short alumina fiber hybrid mesh covered with terminal carboxyl sulfonated polyarylether sulfone particles obtained in step (7) according to the ply design of [0] 16 , carry out vacuum infusion molding at 100 °C and record the complete infusion time. After the infusion is completed, raise the temperature to 180 °C at a rate of 5 °C / min and hold at 180 °C for 2 h to complete the curing and molding of the carbon fiber composite material.

[0052] (9) Cut the carbon fiber composite material obtained in step (8) into specimens with dimensions of 150 mm × 20 mm × 4 mm and 155 mm × 13 mm × 4 mm respectively for testing the mode II interlaminar fracture toughness and flexural properties.

[0053] According to the ASTM D7905 test standard, use end-notched flexure specimens to test the mode II interlaminar fracture toughness of the carbon fiber composite material, and the calculation formula is as follows:

[0054]

[0055] In the formula, G IIC represents the type II interlaminar fracture toughness (J / m 2 ), P Max is the maximum fracture force during the test, a is the crack length (mm) corresponding to the maximum force, B is the sample width (mm), L is half of the span length (50 mm), and the calculation results are shown in Table 1.

[0056] According to the ASTM D7264 test standard, a universal testing machine was used to test the flexural strength of the carbon fiber composite material. The diameters of the support rollers and the indenter were both 10 mm, and the loading rate was 1 mm / min. The calculation formula for the flexural strength is as follows:

[0057]

[0058] In the formula, σ is the flexural strength (MPa), P is the maximum flexural load (N), L is the sample span (mm), b is the sample width (mm), h is the sample thickness (mm), and the calculation results are shown in Table 1.

[0059] Example 2

[0060] This example provides a method for preparing a composite carbon fiber tape covered with a short basalt fiber hybrid mesh yarn containing biphenyl polyarylether sulfone particles, and the steps are as follows:

[0061] (1) Prepare a thermoplastic resin powder mixture by mixing biphenyl polyarylether sulfone, solid epoxy resin E20, and polyethylene oxide in a mass ratio of 5:4:1;

[0062] (2) Add the thermoplastic resin powder mixture obtained in step (1) to water and obtain a suspension with a mass fraction of 35% through mechanical stirring;

[0063] (3) Immerse carbon fiber mesh yarn with an average fiber length of 4 mm and a surface density of 6 g / m 2 in the suspension obtained in step (2) for 1 minute to obtain a short basalt fiber hybrid mesh yarn containing a thermoplastic resin powder mixture;

[0064] (4) Use an infrared heater to dry and heat-set the mesh yarn obtained in step (3) at 75 °C and 250 °C respectively, and then naturally cool to obtain a short basalt fiber hybrid mesh yarn covered with biphenyl polyarylether sulfone particles;

[0065] (5) Introduce 5 g / m on both sides of a 24k T800 unidirectional carbon fiber tape through electrostatic spraying 2Solid epoxy resin E20 powder, with an electrostatic high voltage of 70 kV, an atomizing pressure of 0.7 MPa, a flow rate pressure of 0.3 MPa, and a spraying distance of 150 mm;

[0066] (6) Lay the hybrid mesh obtained in step (4) on both sides of the carbon fiber tape obtained in step (5), and use an infrared heater to preheat the hybrid mesh and the carbon fiber tape to 120 °C;

[0067] (7) Hot press the preheated hybrid mesh and carbon fiber tape in step (6) through a hot press roller group with temperatures and pressures of 60 °C and 0.2 MPa respectively. After natural cooling, a composite carbon fiber tape containing a short basalt fiber hybrid mesh covered with biphenyl polyarylether sulfone particles is obtained;

[0068] (8) Lay the composite carbon fiber tape containing a short basalt fiber hybrid mesh covered with biphenyl polyarylether sulfone particles obtained in step (7) according to the 16 ply design of [0], perform vacuum infusion molding at 100 °C and record the complete infusion time. After the infusion is completed, raise the temperature to 180 °C at a rate of 5 °C / min and hold it at 180 °C for 2 h to complete the curing and molding of the carbon fiber composite material, as Figure 2 shown.

[0069] According to the same sample preparation method and test standard as in Example 1, the mode II interlaminar fracture toughness and flexural properties of the carbon fiber composite material obtained in step (8) were tested, and the calculation results are shown in Table 1.

[0070] Comparative Example 1

[0071] In this comparative example, a unidirectional carbon fiber tape was directly used to prepare a carbon fiber composite material. The difference between the steps and those in Example 1 is that the preparation process of the short alumina fiber hybrid mesh covered with terminal carboxyl sulfonated polyarylether sulfone particles and its composite carbon fiber tape in steps (1)-(7) was omitted. Based on the same process parameters as in Example 1, the vacuum infusion molding process of the unidirectional carbon fiber tape was carried out and the complete infusion time was recorded. Using the same sample preparation method and test standard as in Example 1, the mode II interlaminar fracture toughness and flexural properties of the carbon fiber composite material were obtained, and the results are shown in Table 1.

[0072] Comparative Example 2

[0073] This comparative example provides a method for preparing a composite carbon fiber tape with a short alumina fiber mesh yarn. The steps are basically the same as those in Example 1, except that: the mixed powder in step (1) does not contain thermoplastic resin and is only composed of solid epoxy resin E44 and carboxymethyl cellulose with a mass ratio of 3:1. Using the same process parameters as in Example 1, the vacuum infusion molding process of the composite carbon fiber tape was carried out and the complete infusion time was recorded. Using the same sample preparation method and test standard as in Example 1, the mode II interlaminar fracture toughness and flexural properties of the carbon fiber composite were obtained, and the results are shown in Table 1.

[0074] Table 1

[0075]

[0076] As can be seen from Table 1, the resin infusion times in Examples 1-2 are shorter than that in Comparative Example 1, indicating that the thermoplastic resin particles and carbon fiber hybrid mesh yarn in the composite carbon fiber tape play a role in promoting resin flow; the mode II interlaminar fracture toughness of the carbon fiber composite in Comparative Example 1 is significantly improved compared with that in Comparative Example 2, while the mode II interlaminar fracture toughness of the carbon fiber composite in Examples 1-2 is further improved compared with that in Comparative Example 1, reflecting the excellent toughening effect of the short inorganic fiber hybrid mesh yarn; the flexural strengths of the carbon fiber composites in Examples 1-2 and Comparative Examples 1-2 are relatively close, indicating that the short inorganic fiber hybrid mesh yarn basically does not affect the in-plane mechanical properties of the carbon fiber composite.

[0077] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

Claims

1. A preparation method of a carbon fiber composite material, characterized in that, It includes the following steps: Step (1): Prepare a thermoplastic resin powder mixture by mixing carboxyl-terminated sulfonated polyarylether sulfone, solid epoxy resin E44, and carboxymethyl cellulose in a mass ratio of 6:3:1; Step (2): Add the thermoplastic resin powder mixture obtained in step (1) into water and obtain a suspension with a mass fraction of 40% through mechanical stirring; Step (3) impregnates a short alumina fiber mesh with a surface density of 8 g / m 2 in the suspension obtained in step (2) for 2 minutes to obtain a short alumina fiber mesh containing a thermoplastic resin powder mixture; The length range of the short alumina fibers is 4 - 10 mm, and the diameter range of the short alumina fibers is 3 - 15 μm; Step (4): Use an infrared heater to dry and heat-set the mesh obtained in step (3) at 80°C and 230°C respectively, and then naturally cool to obtain a short alumina fiber hybrid mesh covered with carboxyl-terminated sulfonated polyarylether sulfone particles; Step (5) introduces 10 g / m of solid epoxy resin E44 powder on both sides of the 24kT800 unidirectional carbon fiber tape by electrostatic spraying. The electrostatic high voltage is 65 kV, the atomization pressure is 0.5 MPa, the flow rate pressure is 0.4 MPa, and the spraying distance is 150 mm; 2 ​ Step (5): Place the hybrid mesh obtained in step (4) on both sides of the carbon fiber tape obtained in step (5), and use an infrared heater to preheat the hybrid mesh and the carbon fiber tape to 150°C; Step (6): Hot-press the preheated hybrid mesh and carbon fiber tape in step (6) through a hot-pressing wheel group with a temperature and pressure of 80°C and 0.4 MPa respectively, and obtain a composite carbon fiber tape with a short alumina fiber hybrid mesh covered with carboxyl-terminated sulfonated polyarylether sulfone particles after natural cooling; Step (8) arranges the composite carbon fiber tape of the short alumina fiber hybrid mesh yarn covering the carboxyl-terminated sulfonated polyarylether sulfone particles obtained in step (7) according to the ply design of [[0]] 16 , conducts vacuum infusion molding at 100 °C and records the complete infusion time. After the infusion is completed, it is heated to 180 °C at a rate of 5 °C / min and held at 180 °C for 2 h to complete the curing and molding of the carbon fiber composite material.

2. A carbon fiber composite material obtained by using the preparation method described in claim 1.

3. An application of a carbon fiber composite material obtained by the preparation method according to claim 1 in a liquid-molded carbon fiber composite material.

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