Preparation method of thermoplastic composite materials applicable to automated lay-up in-situ consolidation process

Abstract

This invention belongs to the field of composite material technology, specifically relating to a method for preparing thermoplastic composite materials suitable for automated layup and in-situ consolidation processes. The method includes the following steps: selecting a thermoplastic resin powder with the same structure as the matrix but a lower viscosity; preparing this powder into an aqueous suspension; and sizing the fibers; using the same type of thermoplastic resin powder as in the previous steps, preparing an aqueous suspension with a higher concentration; and using a hot-melt method to prepare a continuous fiber thermoplastic prepreg from the sizing fibers; and cutting the continuous fiber thermoplastic prepreg into narrow thermoplastic strips with widths adapted to the requirements of automated layup and in-situ consolidation processes. The resin in the prepared narrow thermoplastic prepreg strips exhibits good wettability to the fibers, effectively eliminating trapped air during the automated layup and in-situ consolidation process, thus effectively promoting the rapid and reliable application of automated layup and in-situ consolidation technology for aerospace thermoplastic composite materials.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a method for preparing thermoplastic composite materials using an automated layup and in-situ consolidation process. Background Technology

[0002] Thermoplastic composites possess advantages such as good impact resistance, high manufacturing efficiency, weldability, and ease of repair, making them an important development direction for aerospace materials. Thermoplastic composites also exhibit high toughness, fatigue resistance, and reprocessability, overcoming the shortcomings of traditional thermosetting composites, such as insufficient toughness, easy delamination under low-speed impact, and low fatigue limit. During the molding process, the resin undergoes no chemical reaction, resulting in a short molding cycle and high efficiency. Furthermore, their remodeling properties enable welding and in-situ repair of components, effectively reducing the number of fasteners and connectors in traditional parts. They are being used in the structures of military and civilian aircraft abroad, achieving structural weight reduction and performance improvement.

[0003] In-situ consolidation processes eliminate the need for autoclaves, significantly reducing manufacturing costs and shortening molding cycles, with clear demand from both domestic and international aerospace equipment manufacturers. The "melt-consolidation" molding process of thermoplastic composites is ideally suited for in-situ consolidation, achieving superior part performance while saving on the investment in autoclave equipment and auxiliary materials required in traditional manufacturing. This significantly improves manufacturing efficiency and part quality, effectively promoting its engineering and widespread application. In-situ consolidation thermoplastic composites have enormous application potential. Internationally, they have been successfully applied to structures such as the rudder and elevator of the Gulfstream 650, the fuselage panel structure developed in collaboration between Victrex and Coriolis, and the horizontal stabilizer torsion box and fuselage demonstrator components for Airbus. These applications have achieved cost reduction and weight reduction while improving structural damage tolerance and fatigue resistance.

[0004] The in-situ molding process for thermoplastic composites involves rapid heating and cooling, short processing time, and does not require autoclaves or presses. However, it faces challenges such as poor interlayer bonding and high porosity in the finished product. The quality of composites prepared by automated layup in-situ consolidation is closely related to the quality and performance of the prepreg tape used, and the prepreg tape must be compatible with the automated layup in-situ consolidation process. Currently, when using automated layup in-situ consolidation processes with existing thermoplastic prepreg tapes in China, the porosity of the resulting composites is generally greater than 5%, making them difficult to apply in aerospace structural composites. Currently, there are no high-performance thermoplastic prepreg tows suitable for automated layup in-situ consolidation in China. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] This invention addresses the above-mentioned problems by proposing a method for preparing thermoplastic composite materials using an automated layup and in-situ consolidation process. The aim is to solve the problem of high porosity in the preparation of thermoplastic composite materials and promote the rapid and reliable application of automated layup and in-situ consolidation technology for aerospace thermoplastic composite materials.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides a method for preparing thermoplastic composite materials suitable for automated layup and in-situ consolidation processes, the method comprising the following steps:

[0009] S100. Select a thermoplastic resin powder with the same structure as the matrix but with a lower viscosity than the matrix structure. Make this powder into an aqueous suspension and sizing the fiber, controlling the amount of sizing within a specific range.

[0010] S200: Using the same type of thermoplastic resin powder as in step S100, prepare an aqueous suspension with a higher concentration than in step S100, and use a hot melt method to prepare a continuous fiber thermoplastic prepreg from the sizing fiber.

[0011] S300. The obtained continuous fiber thermoplastic prepreg is cut as needed to form a thermoplastic narrow strip with a width that matches the requirements of automatic laying and in-situ consolidation processes.

[0012] Furthermore, the thermoplastic resin powder used is selected from one or more mixtures of polyetheretherketone, polyetherketoneketone, polyetherketone, polyethersulfoneketoneketone, polyethersulfoneetherketoneketone, modified polyethersulfone, and modified polyetherketone, with a particle size D. 50 The range is 0.1 μm-10 μm; the optimal particle size D 50 The range is 1μm-5μm.

[0013] Furthermore, the concentration of the aqueous suspension in step S100 is 1%-10%, with an optimal concentration range of 2%-5%.

[0014] Furthermore, in step S100, after fiber sizing, a high-temperature continuous post-treatment is required, with the treatment temperature between 300℃ and 400℃, and the optimal treatment temperature being 320℃ to 380℃.

[0015] Furthermore, the processing time for continuous high-temperature post-treatment is 10s-60s, with the optimal processing time being 20s-40s.

[0016] Furthermore, the sizing amount should be controlled within the range of 0.5%-8%, with the optimal range being 2%-5%.

[0017] Furthermore, in step S200, the high-performance thermoplastic resin powder similar to the sizing agent includes, but is not limited to, similar thermoplastic resin powders with higher molecular weight and narrower molecular weight distribution, with a particle size D50 range of 1μm-30μm and an optimal particle size D50 range of 5μm-15μm.

[0018] Furthermore, the steps for preparing continuous fiber thermoplastic prepreg by the hot melt method include: yarn threading, yarn spreading, suspension impregnation, high-temperature impregnation, high-temperature roller pressing impregnation, and traction winding.

[0019] Furthermore, the concentration of the aqueous suspension in step S200 is 8%-30%, with an optimal concentration range of 10%-20%.

[0020] Furthermore, in step S200, the temperature range of the high-temperature drying tunnel is 250℃-400℃, with an optimal temperature range of 300℃-380℃. The high-temperature drying tunnel can also be divided into sections, with the temperature gradually increasing from the inlet to the outlet. The tunnel length is 2000mm-4000mm, and the linear speed is 1m / min-5m / min.

[0021] Furthermore, in step S200, the temperature of the high-temperature pressure roller is 50℃-350℃, with the optimal temperature range being 150℃-250℃.

[0022] (III) Beneficial Effects

[0023] Compared with the prior art, the present invention provides a method for preparing thermoplastic composite materials suitable for automated layup and in-situ consolidation processes, which has the following advantages:

[0024] (1) Suitable for preparing low-porosity unidirectional high-performance thermoplastic prepreg: Due to the use of the same low-viscosity resin for carbon fiber sizing and the control of the sizing amount, and the use of the same high-performance powder suspension hot melt method to prepare the prepreg, the resin impregnation effect of carbon fiber is good, and combined with high-temperature hot pressing, the porosity of the prepared thermoplastic prepreg reaches less than 1%.

[0025] (2) The prepared prepreg narrow strip is suitable for automatic laying and in-situ consolidation process: Since the sizing agent is a relatively low viscosity resin of the same type, it is beneficial to impregnate the fiber with resin and also to reduce the viscosity of the resin system, which further facilitates the removal of trapped air during the laying process and reduces the porosity of the composite material.

[0026] (3) Manufacturing environment is safe and friendly: Because water-based suspension is used, there is less pollution and less harm to operators, making the manufacturing environment safe and friendly. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a suspension hot-melt method for preparing thermoplastic prepregs disclosed in this application.

[0028] The reference numerals in the figure are as follows: 1. Yarn frame; 2. Grate; 3. Yarn spreading roller; 4. Fiber guide roller; 5. Suspension tank; 6. Impregnation guide roller; 7. Resin powder suspension; 8. Yarn spreading pressure roller; 9. High-temperature drying tunnel; 10. High-temperature hot press roller; 11. Traction roller; 12. Rewinding unit. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings, and the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0031] Example 1

[0032] On the T800 grade carbon fiber production line, 5% concentration of D 50 A 3μm polyetheretherketone (PEEK) sizing suspension was placed in a sizing agent tank. The PEEK had a melt index of 180 g / min (380℃, 5 kg). After sizing, the fibers underwent rapid high-temperature treatment at 360℃ in a high-temperature furnace before being wound up to obtain specially sized carbon fibers. The sizing agent content of the carbon fibers was tested to be 2.1%.

[0033] The above-mentioned special sizing agent is used to further prepare prepreg using the suspension hot melt method. The preparation process is as follows: Figure 1 As shown. The fiber passes through the yarn frame 1 and the grate 2, then through the spreading roller 3, and via the fiber guide roller 4 into the polyetheretherketone (PEEK) suspension tank 5 (which contains a resin powder suspension 7). After passing through the immersion guide roller 6 in an S-shape, it sequentially passes through the spreading pressure roller 8, the high-temperature drying tunnel 9, the high-temperature hot press roller 10, and the traction roller 11, finally being wound up by the winding unit 12 for later use. The PEEK suspension concentration is 16%, and the PEEK melt index is 90 g / min (380℃, 5 kg). 50 The thickness is 7μm. The temperature range of the high-temperature drying tunnel is 360℃, the tunnel length is 3000mm, and the linear speed is 1m / min; the temperature of the high-temperature pressure roller is 150℃.

[0034] The prepreg, after being wound up, is further continuously slit into narrow strips of 6.35 mm width using a dedicated slitting machine. These strips are then further processed into composite laminates using the same process parameters through an automated in-situ bonding and laying equipment. Tensile properties and short beam strength are then tested according to standard requirements. The basic properties of the prepreg and the composite material are shown in Table 1.

[0035] Example 2

[0036] On the T800 grade carbon fiber production line, 3% concentration of D 50 A 2μm polyetherketone ketone (PEKK) sizing suspension was placed in a sizing agent tank. The PEVKK melt index was 200 g / min (350℃, 5 kg). After sizing, the fibers underwent rapid high-temperature treatment at 330℃ in a high-temperature furnace before being wound up to obtain specially sized carbon fibers. The sizing agent content of the carbon fibers was tested to be 1.8%.

[0037] The above-mentioned special sizing agent is used to further prepare prepreg using the suspension hot melt method. The preparation process is as follows: Figure 1 As shown. The fibers pass through the yarn frame 1, the grate 2, and through the spreading roller 3, then through the fiber guide roller 4 into the polyether ketone ketone suspension tank 5. In an S-shape, they pass through the immersion guide roller 6, then sequentially through the spreading pressure roller 8, the high-temperature drying tunnel 9, the high-temperature hot press roller 10, and the traction roller 11, finally being wound up by the winding unit 12 for later use. The polyether ketone ketone suspension concentration is 13%, wherein the melt index of the polyether ketone ketone is 100 g / min (350℃, 5 kg), and D... 50 The thickness is 8μm. The temperature range of the high-temperature drying tunnel is 330℃, the tunnel length is 2000mm, and the linear speed is 1.5m / min; the temperature of the high-temperature pressure roller is 130℃.

[0038] The prepreg, after being wound up, is further continuously slit into narrow strips of 6.35 mm width using a dedicated slitting machine. These strips are then further processed into composite laminates using the same process parameters through an automated in-situ bonding and laying equipment. Tensile properties and short beam strength are then tested according to standard requirements. The basic properties of the prepreg and the composite material are shown in Table 1.

[0039] Example 3

[0040] On the T800 grade carbon fiber production line, 4% D... 50 A 3μm polyethersulfone ketone sizing suspension was placed in a sizing agent tank. The melt index of the polyethersulfone ketone was 160 g / min (350℃, 5 kg). After sizing, the fibers were subjected to rapid high-temperature treatment at 350℃ in a high-temperature furnace and then wound up to obtain specially sized carbon fibers. The sizing agent content of the carbon fibers was tested to be 2.5%.

[0041] The above-mentioned special sizing agent is used to further prepare prepreg using the suspension hot melt method. The preparation process is as follows: Figure 1 As shown. The fibers pass through the yarn frame 1, the grate 2, and through the spreading roller 3, then through the fiber guide roller 4 into the polyaryletherketone suspension tank 5. In an S-shape, they pass through the immersion guide roller 6, then sequentially through the spreading pressure roller 8, the high-temperature drying tunnel 9, the high-temperature hot press roller 10, and the traction roller 11, finally being wound up by the winding unit 12 for later use. The polyaryletherketone suspension concentration is 13%, and the melt index of the polyaryletherketone is 80 g / min (350℃, 5 kg). 50 The thickness is 10μm. The temperature range of the high-temperature drying tunnel is 350℃, the tunnel length is 3500mm, and the linear speed is 2m / min; the temperature of the high-temperature pressure roller is 200℃.

[0042] The prepreg, after being wound up, is further continuously slit into narrow strips of 6.35 mm width using a dedicated slitting machine. These strips are then further processed into composite laminates using the same process parameters through an automated in-situ bonding and laying equipment. Tensile properties and short beam strength are then tested according to standard requirements. The basic properties of the prepreg and the composite material are shown in Table 1.

[0043] Table 1. Basic properties of the prepared thermoplastic prepregs and composites.

[0044]

[0045] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A method for the production of thermoplastic composites suitable for automated tape- laying in-situ consolidation processes, characterized in that, Includes the following steps: S100. Select a thermoplastic resin powder with the same structure as the matrix but with a lower viscosity than the matrix structure. Make this powder into an aqueous suspension and sizing the fiber, controlling the amount of sizing within a specific range. S200: Using the same type of thermoplastic resin powder as in step S100, prepare an aqueous suspension with a higher concentration than in step S100, and use a hot melt method to prepare a continuous fiber thermoplastic prepreg from the sizing fiber. S300. Cut the obtained continuous fiber thermoplastic prepreg as needed to form a thermoplastic narrow strip with a width that matches the requirements of automatic laying and in-situ consolidation processes. In step S100, after fiber sizing, a high-temperature continuous post-treatment is performed, with the treatment temperature between 300℃ and 400℃; the sizing amount is controlled within the range of 0.5% to 8%.

2. The method for preparing a thermoplastic composite material suitable for automated layup and in-situ consolidation process according to claim 1, characterized in that, The thermoplastic resin powder used is selected from one or more of polyetheretherketone, polyetherketoneketone, polyetherketone, polyethersulfoneketone, polyethersulfoneketone, polyethersulfoneetherketoneketone, modified polyethersulfone, and modified polyetherketone, with a particle size D50 range of 0.1μm-10μm.

3. The method for preparing a thermoplastic composite material suitable for automated layup and in-situ consolidation process according to claim 1, characterized in that, The concentration of the aqueous suspension in step S100 is 1%-10%.

4. The method for preparing a thermoplastic composite material suitable for automated layup and in-situ consolidation process according to claim 1, characterized in that, The processing time for continuous high-temperature post-treatment is 10s-60s.

5. The method for preparing a thermoplastic composite material suitable for automated layup and in-situ consolidation process according to claim 1, characterized in that, The steps for preparing continuous fiber thermoplastic prepreg by the hot melt method include: yarn threading, yarn spreading, suspension impregnation, high-temperature impregnation, high-temperature roller pressing impregnation, and traction winding.

6. The method for preparing a thermoplastic composite material suitable for automated layup and in-situ consolidation process according to claim 1, characterized in that, The concentration of the aqueous suspension in step S200 is 8%-30%.

7. A method for preparing a thermoplastic composite material suitable for automated layup and in-situ consolidation process according to claim 5, characterized in that, In step S200, the temperature range of the high-temperature drying tunnel is 250℃-400℃, with the temperature gradually increasing in segments. The length of the drying tunnel is 2000mm-4000mm, and the linear speed is 1m / min-5m / min.

8. A method for preparing a thermoplastic composite material suitable for automated layup and in-situ consolidation process according to claim 5, characterized in that, In step S200, the temperature of the high-temperature pressure roller is 50℃-350℃.

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