Flexible thermoplastic composite preimpregnated yarn and application

Abstract

The invention belongs to the field of composite materials, and particularly discloses a flexible thermoplastic composite material preimpregnated yarn and application. The spinnable flexible thermoplastic composite material pre-impregnated yarn provided by the invention comprises the following raw materials: reinforced fibers and a thermoplastic matrix, in the flexible thermoplastic composite material pre-impregnated yarn, the thermoplastic matrix is distributed on the reinforced fibers in a microbead form, and the mass content of the thermoplastic matrix in the pre-impregnated yarn is 20-70%. The flexible thermoplastic composite material preimpregnated yarn provided by the invention overcomes the problems that a thermoplastic matrix is high in viscosity and is difficult to infiltrate reinforced fibers, can be applied to weaving, weaving and other spinning procedures, realizes spatial arrangement of fibers in a thermoplastic composite material, and improves the mechanical contribution rate of the reinforced fibers in the thermoplastic composite material. Meanwhile, the structure of the thermoplastic composite material can be expanded to 2D and 3D, the capacity of the thermoplastic composite material for preparing components in complex shapes is improved, and application of the thermoplastic composite material to force bearing components is promoted.

Description

Technical Field

[0001] The invention belongs to the field of composite materials, and in particular relates to a flexible thermoplastic composite material preimpregnated yarn and an application thereof. Background Art

[0002] Compared with thermosetting composites, thermoplastic composites (FRTP) have the advantages of high toughness, impact resistance, short preparation cycle, convenient transportation and storage, weldability, melt reshaping, and environmental protection. They are increasingly widely used in aerospace, marine engineering, medical and other fields. However, the high viscosity of the thermoplastic matrix and the difficulty in uniformly coating and impregnating the reinforcing fibers have brought a series of scientific and practical difficulties to the design and manufacture of continuous fiber reinforced thermoplastic composites, which has limited the development of 2D and 3D reinforced structure thermoplastic composites, resulting in their application still mainly limited to non-load-bearing components.

[0003] At present, prepregs or composite materials obtained by methods such as hot melt, solution, suspension, surface polymerization, fiber blending and film stacking are usually very hard and brittle, and it is impossible to provide prepreg materials suitable for textile processes such as weaving, weaving and knitting. Therefore, it is difficult to manufacture complex shapes and complex structures, which limits the application of thermoplastic composite materials in load-bearing structures. Prepreg yarn is a combination of resin matrix and reinforcing material. According to different resin matrices, prepreg yarn can be divided into thermosetting and thermoplastic prepreg yarns. Under room temperature conditions, thermosetting resins are highly viscous, so the surface of thermosetting prepreg yarns is relatively sticky and not suitable for use in textile processes; while thermoplastic resins commonly used in thermoplastic prepreg yarns, such as polypropylene, polyetheretherketone and polyetherketoneketone, are solid at room temperature, resulting in hard and brittle prepreg materials that cannot be used in textile processes. In Chinese patent application number CN201811392801, a method of modifying a thermosetting resin matrix was used to successfully prepare a thermosetting prepreg yarn that can be three-dimensionally woven semi-mechanized and semi-manually. However, when the fiber yarn is used for machine weaving, the friction between the yarn and the machine generates heat, causing the resin to gradually melt, which in turn causes the resin to fall off and the yarn to break; Chinese patent application number CN202010688783 discloses that a continuous fiber bundle is impregnated with a thermosetting resin impregnation solution to obtain a pre-impregnated fiber bundle, and then an organic solvent is used to dissolve the thermoplastic resin to prepare a sizing agent to spray or brush on the surface of the pre-impregnated fiber bundle to obtain a thermoplastic resin sizing three-dimensional weaving pre-impregnated fiber bundle, so as to improve the problem of resin falling off and yarn breaking when only thermosetting resin is used to make pre-impregnated yarn. Compared with the prior art, the present invention provides a weavable flexible thermoplastic composite pre-impregnated yarn, the surface of which is bonded with discontinuous thermoplastic powder microbeads, and a composite material with complex shapes and structures can be manufactured.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The present invention aims to overcome the problems of high viscosity of thermoplastic matrix and difficulty in impregnating reinforcing fibers, and provides a flexible thermoplastic composite material preimpregnated yarn. The yarn has high flexibility and can be used in textile processes such as knitting and weaving. The preimpregnated yarn provided by the present invention can be used to manufacture composite materials with complex shapes and complex structures.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] The first object of the present invention is to provide a flexible thermoplastic composite material preimpregnated yarn, the raw materials of which include reinforcing fibers and a thermoplastic matrix. In the flexible thermoplastic composite material preimpregnated yarn, the thermoplastic matrix is ​​distributed on the reinforcing fibers in the form of microbeads.

[0008] In the technical solution of the present invention, the thermoplastic matrix is ​​distributed on the reinforcing fiber in the form of microbeads. This discontinuous microbead structure allows the fiber to retain a certain flexibility, so that the prepreg yarn has better flexibility and ductility, which is beneficial to subsequent weaving, weaving and knitting processes, and is suitable for the preparation of composite materials with complex shapes and structures.

[0009] In the above technical solution, the thermoplastic matrix is ​​bonded to the reinforcement fibers in the form of discontinuous microbeads.

[0010] In the above technical solution, the mass content of the thermoplastic matrix in the prepreg yarn is 20%-70%.

[0011] In the above technical solution, the thermoplastic matrix is ​​in powder form as a raw material, and the ratio of the particle size of the thermoplastic matrix powder to the diameter of the reinforcing fiber is n≤4.

[0012] Optionally, the ratio of the particle size of the thermoplastic matrix powder to the diameter of the reinforcing fibers is 1.

[0013] The closer the particle size of the thermoplastic matrix powder is to the diameter of the reinforcing fiber, the more uniform the microbeads formed. The resin powder with a smaller particle size can adhere to the fiber surface more evenly and form a uniform covering layer during the melting process. When the ratio of the particle size of the thermoplastic matrix powder to the diameter of the reinforcing fiber is greater than 4, the resin powder may be difficult to evenly coat on the fiber surface, resulting in uneven coating thickness, and even resin accumulation or blank areas, affecting the performance of the composite material.

[0014] In the above technical solution, the thermoplastic matrix is ​​selected from at least one of PEEK, PEAK, LCP, PI, PBI, PEI, PARA, PPS, PA, and PC.

[0015] In the above technical solution, the reinforcement fiber is selected from at least one of carbon fiber, glass fiber, basalt fiber, quartz fiber, silicon carbide fiber, silicon nitride fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, polyamide fiber, PEEK fiber, PEAK fiber, PI fiber, and LCP fiber.

[0016] In the above technical solution, the knotting strength of the weavable flexible thermoplastic composite material prepreg yarn is 178Mpa-259Mpa, and the hooking strength is 317MPa-456Mpa.

[0017] The second object of the present invention is to provide a flexible thermoplastic composite material prepreg yarn for use in textiles;

[0018] Preferably, the weaving includes weaving, knitting and braiding.

[0019] The third object of the present invention is to provide a preimpregnated fabric, which is woven using the preimpregnated yarn of the flexible thermoplastic composite material of the present invention.

[0020] The fourth object of the present invention is to provide a thermoplastic composite material, which is made by using the flexible thermoplastic composite material preimpregnated yarn or the above-mentioned preimpregnated fabric of the present invention;

[0021] Preferably, the thermoplastic composite material has a two-dimensional or three-dimensional structure;

[0022] Preferably, the thermoplastic composite material is used to prepare load-bearing components.

[0023] The flexible thermoplastic composite material preimpregnated yarn or preimpregnated fabric processed by a weaving process provided by the present invention can melt the resin by heating to quickly obtain thermoplastic composite materials of various shapes and structures. In addition, when the composite material is manufactured by injection molding, RTM molding and other methods, the thermoplastic powder microbeads on the surface of the preimpregnated yarn will increase the resin's infiltration of the reinforcing fiber and reduce the porosity in the composite material because similar things dissolve in each other.

[0024] The present invention can expand the structure of thermoplastic composite materials to 2D and 3D, and improve the ability of thermoplastic composite materials to prepare complex-shaped components. The prepreg yarn, combined with subsequent textile processes, can promote the application of thermoplastic composite materials in load-bearing components, and has a wide range of use needs in aerospace, rail transportation, sports and leisure, construction and other fields.

[0025] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art.

[0026] The present invention provides a weavable flexible thermoplastic composite prepreg yarn that can be used in weaving processes such as knitting and weaving, overcoming the problems of high viscosity of the thermoplastic matrix and difficulty in impregnating the reinforcing fibers, realizing the spatial arrangement of the fibers in the thermoplastic composite material, and improving the mechanical contribution rate of the reinforcing fibers in the thermoplastic composite material. At the same time, the structure of the thermoplastic composite material can be expanded to 2D and 3D, improving the ability of the thermoplastic composite material to prepare complex-shaped components, and promoting the application of thermoplastic composite materials in load-bearing components.

[0027] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the accompanying drawings:

[0029] Figure 1 It is a schematic diagram of the structure of the flexible thermoplastic composite material prepreg yarn of the present invention;

[0030] Reference numerals: 1 - reinforcing fibers; 2 - thermoplastic matrix microbeads.

[0031] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0033] In the description of the present invention, it should be noted that the term "prepreg yarn" refers to a yarn formed by pre-setting a matrix material into a reinforcement fiber. The embodiments use a single type of reinforcement fiber and matrix material, and are only used to exemplify the flexible thermoplastic composite prepreg yarn and its composite material, rather than indicating or implying that the prepreg yarn is only applicable to a single material, and therefore cannot be understood as a limitation of the present invention. The test methods for knotting strength and hooking strength in the embodiments refer to the national standards "Prepreg Performance Test Method Part 4: Determination of Tensile Strength" (GB / T 32788.4-2016) and "Strength Test of Packaged Yarn and Thread Part 2: Determination of Knotting Strength and Hooking Strength" (BS1932-2-1989).

[0034] like Figure 1 As shown, the thermoplastic matrix microbeads 2 are discontinuously distributed on the surface of the reinforcing fiber 1 .

[0035] Example 1

[0036] The reinforcing fiber of this embodiment is 12K carbon fiber, and the thermoplastic resin powder is 800 mesh PEEK powder. The specific operation steps are as follows:

[0037] (1) The 12K carbon fiber is drawn out from the creel and subjected to a high-temperature desizing process to remove the original sizing agent on the surface of the carbon fiber, wherein the high-temperature desizing temperature is 400°C;

[0038] (2) The desized carbon fiber is stretched into a thin layer of 25-35 mm wide and 0.01-0.05 mm thick through a yarn spreading process;

[0039] (3) impregnating the surface of the stretched carbon fiber with a layer of water-soluble polyetheretherketone sizing agent for sizing, wherein the mass of the sizing agent impregnated on the surface of the carbon fiber is 1% of the mass of the carbon fiber after desizing;

[0040] (4) drying / preheating the sized carbon fiber at 120° C. to form a sizing agent film on the surface of the carbon fiber;

[0041] (5) sending the dried / preheated carbon fiber into a powder coating chamber, and adhering PEEK powder to the carbon fiber by sprinkling, wherein the fiber passes through at a speed of 1.5 m / min;

[0042] (6) feeding the carbon fiber coated with PEEK powder into a heating furnace for heating at a temperature of 430° C., so that the PEEK powder attached to the carbon fiber is melted and bonded to the carbon fiber in the form of discontinuous micro beads;

[0043] (7) The carbon fiber bonded with the PEEK microbeads is cooled and solidified, and finally wound on a yarn reel to obtain a flexible thermoplastic composite prepreg yarn with a thermoplastic resin mass content of 40%.

[0044] (8) The obtained flexible thermoplastic composite prepreg yarn was subjected to multiple knotting strength and hook strength tests, and the average knotting strength of the flexible thermoplastic composite prepreg yarn of Example 1 was measured to be 222 MPa, and the average hook strength was 389 MPa. The knotting strength and hook strength can indicate its flexibility and weavability. The detailed data of the knotting strength test are shown in Table 1, and the detailed data of the hook strength test are shown in Table 2.

[0045] Table 1:

[0046] Number of experiments Maximum force applied (N) Tensile strength(MPa) 1 233.01 258.90 2 175.31 194.79 3 230.51 256.12 4 160.44 178.27 average value 199.82 222.02

[0047] Table 2:

[0048] Number of experiments Maximum force applied (N) Tensile strength(MPa) 1 285.57 317.31 2 349.81 388.67 3 358.01 397.79 4 346.60 385.11 5 410.25 455.83 average value 350.05 388.94

[0049] (9) The obtained flexible thermoplastic composite material prepreg yarn is arranged on a 9×22 three-dimensional braiding machine to weave a 4×19 three-dimensional braided part. The process operation file is shown in Table 3;

[0050] (10) The specific weaving process steps are as follows. The process operation file of this embodiment is provided as shown in Table 3:

[0051] S1: drives the yarns on columns A1-3, A2-4, A1-5, A2-6, A1-7, A2-8, A1-9, A2-10, A1-11, A2-12, A1-13, A2-14, A1-15, A2-16, A1-17, A2-18, A1-19 and A2-20 to move;

[0052] S2: drives the yarn movement on rows B1-4, B2-5 and B1-6;

[0053] S3: yarn movement on columns A2-3, A1-4, A2-5, A1-6, A2-7, A1-8, A2-9, A1-10, A2-11, A1-12, A2-13, A1-14, A2-15, A1-16, A2-17, A1-18, A2-19, and A1-20;

[0054] S4: drives the yarn movement on the rows of B2-4, B1-5 and B2-6;

[0055] S5: Repeat the cycle S1-S4 to obtain a 4×19 three-dimensional woven part

[0056] Table 3:

[0057]

[0058] (11) After preheating, the obtained three-dimensional woven part is placed in a mold. In order to ensure that the temperature inside and outside the preform is as consistent as possible, infrared heating is used to assist the preform. The preform is hot-pressed at a temperature of 480°C and a pressure of 1 MPa to obtain a carbon fiber reinforced polyetheretherketone composite material.

[0059] Example 2

[0060] The reinforcing fiber of this embodiment is quartz fiber, and the thermoplastic resin powder is 800 mesh LCP powder. The temperature of the heating furnace in step (6) of Example 1 is changed, that is, the quartz fiber coated with LCP powder enters the heating furnace for heating, and the heating furnace temperature is 320°C. The other specific process steps are the same as those in Example 1, and a flexible thermoplastic composite material prepreg yarn with a thermoplastic resin mass content of 40% is obtained, and the flexible thermoplastic composite material is woven through the same steps as steps (9)-(11) in Example 1 to obtain a flexible thermoplastic composite material.

[0061] Example 3

[0062] The reinforcing fiber of this embodiment is glass fiber, and the thermoplastic resin powder is 800 mesh PA powder. The temperature of the heating furnace in step (6) of Example 1 is changed, that is, the glass fiber coated with PA powder enters the heating furnace for heating, and the heating furnace temperature is 260°C. The other specific process steps are the same as those in Example 1, and a flexible thermoplastic composite material prepreg yarn with a thermoplastic resin mass content of 40% is obtained, and the flexible thermoplastic composite material is woven through the same steps as steps (9)-(11) in Example 1 to obtain a flexible thermoplastic composite material.

[0063] Example 4

[0064] The reinforcing fiber of this embodiment is 12K carbon fiber, the thermoplastic resin powder is 800 mesh PPS powder, the carbon fiber is drawn out from the creel, and after being unrolled and preheated, it directly enters the coating chamber for PPS powder coating. The specific operation steps are as follows:

[0065] (1) The 12K carbon fiber is drawn out from the creel and stretched into a thin layer of 25-35 mm wide and 0.01-0.05 mm thick through a yarn spreading process;

[0066] (2) preheating the stretched carbon fiber at 120° C.;

[0067] (5) The preheated carbon fiber is sent into a powder coating chamber, and the PPS powder is attached to the carbon fiber by a powdering method, wherein the fiber passes through at a speed of 1.5 m / min;

[0068] (6) The carbon fiber coated with PPS powder is sent to a heating furnace for heating at a temperature of 320° C., so that the PPS powder attached to the carbon fiber is melted and bonded to the carbon fiber in the form of discontinuous micro beads;

[0069] (7) The carbon fiber bonded with the PPS microbeads is cooled and solidified, and finally wound on a yarn reel to obtain a flexible thermoplastic composite prepreg yarn with a thermoplastic resin mass content of 40%.

[0070] (8) The obtained flexible thermoplastic composite material preimpregnated yarn is woven through the same steps as steps (9) to (11) in Example 1 to obtain a flexible thermoplastic composite material.

[0071] Comparative Example 1

[0072] The reinforcing fiber of this comparative example is 12K carbon fiber, and the thermoplastic resin is PEEK. The specific operation steps are as follows:

[0073] (1) The 12K carbon fiber is drawn out from the creel and subjected to a high-temperature desizing process to remove the original sizing agent on the surface of the carbon fiber, wherein the high-temperature desizing temperature is 400°C;

[0074] (2) The desized carbon fiber is stretched into a thin layer of 25-35 mm wide and 0.01-0.05 mm thick through a yarn spreading process;

[0075] (3) impregnating a layer of water-soluble polyetheretherketone sizing agent on the surface of the stretched carbon fiber for sizing;

[0076] (4) drying / preheating the sized carbon fiber at 120° C. to form a sizing agent film on the surface of the carbon fiber;

[0077] (5) feeding the dried / preheated carbon fiber into a sizing tank containing PEEK melt at a temperature of 343°C-600°C to completely impregnate the carbon fiber with PEEK resin;

[0078] (6) feeding the carbon fiber impregnated with PEEK resin into the bell mouth to remove excess resin, and then cooling and forming;

[0079] (7) Finally, the yarn is wound on a yarn shaft to obtain a carbon fiber reinforced PEEK prepreg yarn with a thermoplastic resin mass content of 50%.

[0080] Comparative Example 2

[0081] The reinforcing fiber of this comparative example is 12K carbon fiber (the sizing agent is polyurethane), and the thermoplastic resin is PA6. The specific operation steps are as follows:

[0082] (1) The 12K carbon fiber is drawn out from the creel and stretched into a thin layer of 25-35 mm wide and 0.01-0.05 mm thick through a yarn spreading process;

[0083] (2) feeding the stretched carbon fiber into a sizing tank containing PA6 melt at a temperature of 260°C to completely impregnate the carbon fiber with PA6 resin;

[0084] (3) The carbon fiber impregnated with PA6 resin is fed into the bell mouth to remove excess resin, and then cooled to form;

[0085] (4) Finally, the yarn is wound on a yarn shaft to obtain carbon fiber reinforced PA6 prepreg yarn with a thermoplastic resin mass content of 50%.

[0086] experiment:

[0087] The knotting strength and hook strength of the prepreg yarns obtained in Examples 1-4 and Comparative Examples 1-2 were measured, and the results are summarized in Table 4:

[0088] Table 4:

[0089] Serial number Knot strength / MPa Hook strength / MPa Example 1 222 389 Example 2 203 350 Example 3 212 358 Example 4 225 337 Comparative Example 1 0 0 Comparative Example 2 0 0

[0090] It can be seen from the experimental results that the knotting strength and hook strength of Examples 1-4 are higher than those of Comparative Examples 1-2. Moreover, the thermoplastic prepreg yarns of Comparative Examples 1-2 are hard and brittle at room temperature, and their knotting strength and hook strength are both 0 MPa, which cannot be used for textile applications. Therefore, compared with existing thermoplastic prepreg yarns, the flexible thermoplastic composite prepreg yarn of the present invention can be used in textile processes such as weaving, knitting, and knitting. When used in thermoplastic composite materials, the structure of the thermoplastic composite material can be expanded to 2D and 3D, thereby improving the ability of thermoplastic composite materials to prepare complex shapes and complex structural components.

[0091] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the present invention can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A flexible thermoplastic composite prepreg yarn, characterized in that: The raw materials include reinforcing fibers and a thermoplastic matrix. In the flexible thermoplastic composite material preimpregnated yarn, the thermoplastic matrix is ​​distributed on the reinforcing fibers in the form of micro beads.

2. A flexible thermoplastic composite prepreg yarn according to claim 1, characterized in that: The thermoplastic matrix is ​​bonded to the reinforcement fibers in the form of discontinuous micro beads.

3. The flexible thermoplastic composite prepreg yarn according to claim 1, characterized in that: The mass content of the thermoplastic matrix in the prepreg yarn is 20%-70%.

4. A flexible thermoplastic composite prepreg yarn according to any one of claims 1 to 3, characterized in that: The thermoplastic matrix is ​​in powder form as a raw material, and the ratio of the particle size of the thermoplastic matrix powder to the diameter of the reinforcing fiber is n≤4; Preferably, the ratio of the particle size of the thermoplastic matrix powder to the diameter of the reinforcing fiber is 1.

5. A flexible thermoplastic composite prepreg yarn according to any one of claims 1 to 4, characterized in that: The thermoplastic matrix is ​​selected from at least one of PEEK, PEAK, LCP, PI, PBI, PEI, PARA, PPS, PA, and PC.

6. A flexible thermoplastic composite prepreg yarn according to any one of claims 1 to 4, characterized in that: The reinforcement fiber is selected from at least one of carbon fiber, glass fiber, basalt fiber, quartz fiber, silicon carbide fiber, silicon nitride fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, polyamide fiber, PEEK fiber, PEAK fiber, PI fiber, and LCP fiber.

7. The flexible thermoplastic composite prepreg yarn according to claim 1, characterized in that: The knotting strength of the textile flexible thermoplastic composite prepreg yarn is 178Mpa-259Mpa, and the hooking strength is 317MPa-456Mpa.

8. Use of the flexible thermoplastic composite prepreg yarn according to claims 1 to 7 in textiles; Preferably, the weaving includes weaving, knitting and braiding.

9. A preimpregnated fabric, woven from the flexible thermoplastic composite material preimpregnated yarn according to any one of claims 1 to 7.

10. A thermoplastic composite material, made by using the flexible thermoplastic composite preimpregnated yarn according to any one of claims 1 to 7 or the preimpregnated fabric according to claim 9; Preferably, the thermoplastic composite material has a two-dimensional or three-dimensional structure; Preferably, the thermoplastic composite material is used to prepare load-bearing components.

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