Thermoplastic high-strength fiber covering yarn composite material and preparation method thereof
Through the thermoplastic high-strength fiber core-encapsulated yarn precast composite materials and their preparation methods, the problems of low flexibility, inconvenience in storage and transportation and insufficient mechanical properties of traditional composite precast parts are solved, and prefabricated sleeves with high flexibility, low space occupancy and excellent mechanical properties are achieved. They are suitable for the fields of national defense and military industry, aerospace, sports and leisure.
Patent Information
- Application Number
- CN202411848877.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-03-14
AI Technical Summary
Traditional prepreg composite prefabricated parts have low flexibility, easy to delaminate, and are inconvenient to store and transport, high manufacturing costs, low in-plane shear strength and inter-layer shear strength, and low stiffness in the thickness direction, resulting in low designability.
The thermoplastic high-strength fiber core-clad yarn is used to prepare a composite material and its preparation method. By immersing the core yarn in a resin sizing agent and resin slurry for pre-precipitation, the yarn is coated on the surface of the high-strength fiber core yarn by a multi-spin weaving machine, and a pre-set sleeve for core-clad yarn is formed by braiding, and finally curing in a high-temperature mold.
Prefabricated casing with high flexibility and low space occupancy is achieved, which is convenient for storage and transportation, reduces storage and transportation costs, and improves mechanical properties and surface uniformity, overcoming the fatal weakness of low interlayer strength and easy layering between traditional laminated composite materials.
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Abstract
Description
Technical Field
[0001] The invention belongs to the fields of textile technology and composite material technology, and relates to a thermoplastic high-strength fiber core-spun yarn prefabricated composite material and a preparation method thereof. Background Art
[0002] Fiber-reinforced composites are widely used in defense, aerospace, sports and leisure due to their advantages such as high strength-to-weight ratio, high productivity, recyclability, weldability, higher damage tolerance and longer high-temperature service life. However, traditional prepreg composite preforms have low flexibility, are easily delaminated and are inconvenient to store and transport. In addition, prepreg composite preforms are expensive and time-consuming to manufacture, have low in-plane shear strength and interlaminar shear strength, and have low thickness stiffness, resulting in low designability. In recent years, with the development of composite material processing technology, braiding technology has become a strong candidate technology in fiber-reinforced composite manufacturing technology, which produces hollow tubular preforms by interweaving the reinforcing fibers at a certain angle to the axis of the preform. This is achieved by using a braiding machine that moves the spool containing the fiber in a serpentine circular path while pulling the free end of the fiber at a controlled speed. During the braiding process, the shape and direction of the braiding mandrel can be controlled to produce a near-net-shape preform and minimize the waste generated by trimming operations. From a performance perspective, compared with laminated composites with unidirectional fibers in each layer, woven composite structures have better mechanical properties, higher impact resistance, and better flexibility. Due to the specific distribution of yarns in the microstructure, woven structural composites have excellent mechanical properties. Weaving technology has promoted the development of fiber-reinforced composites, but it can only achieve a multi-layer structure through repeated weaving-dipping, and still faces problems such as difficulty in dipping, low flexibility, easy delamination, and inconvenient storage and transportation. Summary of the invention
[0003] The purpose of the present invention is to provide a thermoplastic high-strength fiber core-spun yarn prefabricated composite material and a preparation method thereof. The thermoplastic high-strength fiber core-spun yarn prefabricated composite material of the present invention has the characteristics of high resin content, high structural stability and excellent interface performance, and also has high flexibility, and can be packaged by folding, winding, winding, etc., so as to achieve extremely low space occupancy, facilitate storage and transportation, and greatly reduce storage and transportation costs.
[0004] The present invention provides a method for preparing a thermoplastic high-strength fiber core-spun yarn composite material, comprising the following steps: 1) impregnating the core yarn in a resin sizing agent and a resin slurry for pre-impregnation to obtain a high-strength fiber core yarn; Wherein, the material of the resin slurry is selected from at least one of polyetheretherketone, nylon and polypropylene; 2) using a multi-spindle braiding machine to wrap the yarn on the surface of the high-strength fiber core yarn to obtain a braided core-spun yarn; 3) weaving the braided core-spun yarn through the multi-spindle braiding machine to obtain a core-spun yarn pre-set sleeve; 4) Curing the core-spun yarn pre-set sleeve to obtain a thermoplastic carbon fiber braided reinforced composite material.
[0005] In the above preparation method, in step 1), the material of the core yarn is selected from at least one of carbon fiber, glass fiber and basalt fiber; The material of the yarn is selected from at least one of polyetheretherketone, nylon and polypropylene; The resin sizing agent includes at least one of a dichloromethane solution of ethylene-methyl acrylate-glycidyl methacrylate, cyclohexanone, and polyetheretherketone.
[0006] In the above preparation method, based on the mass of the braided core-spun yarn, the amount of the resin sizing agent can be 1-2wt%, and the amount of the resin slurry can be generally 10-25wt% according to the required resin content ratio of the product. In the above preparation method, in step 2), the parameters of the multi-spindle braiding machine are set as follows: the braiding pitch can be 5~15mm, the braiding speed is 30~50m / h (the braiding angle is jointly regulated by the braiding pitch and the braiding speed), and the number of braiding spindles is 4~16 spindles.
[0007] In the present invention, when determining the parameters of the multi-spindle braiding machine, the braiding mesh count is calculated based on the braiding pitch.
[0008] In the above preparation method, in step 3), the parameters of the multi-spindle braiding machine are set as follows: the braiding pitch is 75-150 mm; the number of braiding spindles is greater than 14 spindles (specifically 14-56, determined by the required product diameter, the more spindles used, the larger the product diameter); the braiding speed is 400-600 m / s. When the multi-spindle braiding machine is braiding, a plurality of yarn tubes wrapped with CF / Peek braiding yarn (determined by the required product diameter and braiding density, generally 14-56 spindles) are installed on the spindles of the braiding machine; half or 1 / 4 of the number of spindles are placed on the 0° spindle of the braiding machine for tube braiding.
[0009] In the above-mentioned preparation method, in step 4), the core-spun yarn pre-set sleeve is cured through a core mold; The temperature of curing in the square core mold is 370° C., and the film is pulled out from the square core mold at a speed of 60 mm / min.
[0010] In the above-mentioned preparation method, the curing core mold includes a sheet, a prism, a cylinder or an elliptical cylinder.
[0011] The present invention also provides a thermoplastic carbon fiber braided reinforced composite material prepared by the above preparation method.
[0012] In the present invention, the thermoplastic carbon fiber braided reinforced composite material is applied to the fields of national defense, military industry, aerospace, sports and leisure, etc.
[0013] The present invention has the following beneficial effects: 1. The core-spun yarn developed by the present invention improves the internal resin content and interface performance of the high-strength fiber by sizing and impregnating the high-strength fiber before wrapping, so that the resin can be distributed in large quantities and evenly inside the high-strength fiber when the prefabricated sleeve is cured, thereby improving the mechanical properties and surface uniformity of the prefabricated sleeve after curing.
[0014] 2. The existing high-strength fiber core-spun yarn is a method of winding the coated wire on the surface of the carbon fiber in the form of Z twist or S twist. The core-spun yarn obtained in this way has a low coverage rate, which will cause local stress concentration on the surface of the carbon fiber, thereby damaging the carbon fiber and affecting its mechanical properties. The present invention uses a braiding technology to use multiple spindles (4 spindles, 8 spindles, 16 spindles, etc.) of resin wires to braid and entangle the high-strength fiber surface to achieve complete coverage of the high-strength carbon fiber, which will not only not damage the high-strength fiber but also provide protection for its core wire. The high-strength core-spun yarn obtained in this way will have more excellent mechanical properties and weavability.
[0015] 3. The high-flexibility prefabricated sleeve developed by the present invention can be bent, folded and wound, and has a higher space utilization rate than traditional hard fiber reinforced composite materials, and is convenient for storage and transportation. The prefabricated sleeve is cured by a high-temperature mold, and the prefabricated sleeve after high-temperature curing changes from flexible to rigid. Compared with prepregs such as traditional sheets and laminates, the high-strength fiber core-spun yarn prefabricated sleeve developed by the present invention has similar mechanical properties and flexible curing shape. It can change its own molding shape according to different application scenarios by adding a curing core mold and changing the shape of the core mold, and can realize flexible transformation of various morphologies such as sheets, prisms, cylinders, and elliptical columns. The flexibility of the configuration can make its application scenarios more diverse. From the perspective of mechanical properties, each layer inside a sheet or laminated prefabricated composite material is unidirectional fiber, and the fibers are independent of each other. When load-bearing, only the fiber direction shows a reinforcing effect; while the high-strength fibers in the braided sleeve prefabricated composite material cross each other in a spiral path, and when load-bearing, the fibers are subjected to forces in multiple directions. This interconnected woven integrated reinforcement structure between fibers fundamentally overcomes the fatal weaknesses of layered composite materials, such as low interlayer strength and easy stratification, and exhibits higher specific strength, specific modulus, impact resistance and tolerance. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of the preparation process of the "high-strength fiber core-spun yarn" of the present invention.
[0017] Figure 2 It is a schematic diagram of the preparation process of the "thermoplastic high-strength fiber core-spun yarn prefabricated sleeve" of the present invention.
[0018] Figure 3 This is a physical picture of the CF / PEEK braided yarn braided sleeve prepared in Example 1 of the present invention.
[0019] Among them, 1-unwinder; 2-high-strength fiber; 3-heating cylinder; 4-yarn guide roller; 5-sizing tank; 6-impregnation tank; 7-braiding machine bobbin; 8-resin yarn; 9-high-strength fiber core-spun yarn; 10-braiding machine bobbin; 11-tube placement platform; 12-high-strength fiber core-spun yarn prefabricated sleeve DETAILED DESCRIPTION Unless otherwise specified, the experimental methods used in the following examples are conventional methods.
[0020] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.
[0021] In order to further illustrate the present invention, the technical solutions and applications provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0022] Example 1 Eight 238D / 30F polyetheretherketone (PEEK) yarns were used to wrap one 3k / T700 carbon fiber (CF) pre-impregnated with PEEK slurry to prepare CF / PEEK core-spun yarn, and then 56 CF / PEEK core-spun yarns were used to weave a flexible prefabricated sleeve, which was finally cured at high temperature and used as the supporting beam of the solar energy conversion film of the space station.
[0023] The preparation method of the CF / PEEK braided yarn prefabricated sleeve provided in this embodiment and the curing molding thereof to obtain a thermoplastic carbon fiber braided reinforced composite material specifically include the following steps: 1. Use the prepreg sizing system to de-size and sizing the purchased 3k carbon fiber. The specific process is as follows: Place the carbon fiber on a constant tension unwinding device, pass the constant tension yarn through a 400-degree Celsius heating cylinder to remove the surface resin, and then pass the yarn unwinding device to flatten the carbon fiber. Then, pass the carbon fiber through polyetheretherketone (PEEK) slurry, and then enter a 400-degree Celsius heating drum for drying. Finally, rewind at a constant tension to complete the preparation of PEEK prepreg carbon fiber.
[0024] 2. Use a wire splitter to wind 238D / 30F polyetheretherketone (PEEK) yarn on 8 standard bobbins at a constant tension.
[0025] 3. Using one 3k / T700 PEEK pre-impregnated carbon fiber (CF) as the core wire and eight PEEK yarns as the covering wires, CF / PEEK braided yarn was prepared. Figure 2 The weaving parameters are set as follows: weaving mesh: 7 mesh, weaving speed: 50m / h, weaving spindle number: 8 spindles.
[0026] 4. Use a wire splitter to pack the braided CF / Peek braided yarn and wind it on the standard yarn tube of the braiding machine. Install 56 yarn tubes wrapped with CF / Peek braided yarn on the spindle of the braiding machine; place 4 yarn tubes wrapped with CF / PEEK braided yarn on the 0° spindle of the braiding machine for tube sleeve braiding. The actual picture of the braided sleeve is as follows Figure 3 The weaving parameters are: weaving pitch: 60 mm; number of weaving spindles: 56; weaving speed: 60 m / h.
[0027] 5. The prepared CF / PEEK braided yarn braided sleeve is passed through a 0.7×0.7 mm square core mold and pulled out from a 370°C high-temperature mold cavity at a uniform speed of 60 mm / min to achieve solidification, thereby obtaining a thermoplastic carbon fiber braided reinforced composite material.
[0028] Embodiment 2, The method of Example 1 of the present invention is used for preparation, except that the carbon fiber is replaced by glass fiber.
[0029] The mechanical properties of the carbon fiber / polyetheretherketone core-spun yarn braided sleeve (denoted as CF / PEEK-PL) and the glass fiber / polyetheretherketone core-spun yarn braided sleeve (denoted as GF / PEEK-PL) prepared by the above Examples 1-2 are shown in Table 1.
[0030] Table 1
[0031] According to Table 1, the uniformity of CF / PEEK-PL and GF / PEEK-PL is above 96%, which proves that the braiding effect of the present invention is good; the tensile strength of CF / PEEK-PL braided with the same number of spindles is better than that of GF / PEEK-PL, and the elongation at break of GF / PEEK-PL is better than that of CF / PEEK-PL; with the increase of the number of braiding spindles, the tensile strength of GF / PEEK-PL and CF / PEEK-PL increases sharply, and the elongation at break decreases slightly.
[0032] The mechanical properties of the carbon fiber / polyetheretherketone core-spun yarn braided sleeve (CF / PEEK-PL) and the glass fiber / polyetheretherketone core-spun yarn braided sleeve (GF / PEEK-PL) prepared in the above Examples 1-2 after high temperature curing are shown in Table 2.
[0033] Table 2
[0034] According to Table 2, the high-strength fiber / resin core-spun yarn braided sleeve changes from flexibility to rigidity after high-temperature curing, and the bending strength of CF / PEEK-PL is better than that of GF / PEEK-PL. The tensile strength of CF / PEEK-PL increases by more than 3 times after high-temperature curing, and the elongation at break also increases slightly; the tensile strength of GF / PEEK-PL increases by more than 2 times after high-temperature curing, and the elongation at break also increases slightly. The tensile strength of CF / PEEK-PL braided with the same number of spindles is better than that of GF / PEEK-PL, and the elongation at break of GF / PEEK-PL is better than that of CF / PEEK-PL; with the increase of the number of braided spindles, the tensile strength of GF / PEEK-PL and CF / PEEK-PL increases sharply, and the elongation at break decreases slightly.
Claims
1. A method for preparing a thermoplastic high-strength fiber core-spun yarn composite material, comprising the following steps: 1) impregnating the core yarn in a resin sizing agent and a resin slurry for pre-preg treatment to obtain a high-strength fiber core yarn; in, The material of the resin slurry is selected from at least one of polyetheretherketone, nylon and polypropylene; 2) using a multi-spindle braiding machine to wrap the yarn on the surface of the high-strength fiber core yarn to obtain a braided core-spun yarn; 3) weaving the braided core-spun yarn through the multi-spindle braiding machine to obtain a core-spun yarn pre-set sleeve; 4) Curing the core-spun yarn pre-set sleeve to obtain a thermoplastic carbon fiber braided reinforced composite material.
2. The preparation method according to claim 1, characterized in that: In step 1), the material of the core yarn is selected from at least one of carbon fiber, glass fiber and basalt fiber; The material of the yarn is selected from at least one of polyetheretherketone, nylon and polypropylene; The resin sizing agent includes at least one of a dichloromethane solution of ethylene-methyl acrylate-glycidyl methacrylate, cyclohexanone, and polyetheretherketone.
3. The preparation method according to claim 1 or 2, characterized in that: In step 2), the parameters of the multi-spindle braiding machine are set as follows: the braiding pitch is 5-15 mm, the braiding speed is 30-50 m / h, and the number of braiding spindles is 4-16 spindles.
4. The preparation method according to any one of claims 1 to 3, characterized in that In step 3), the parameters of the multi-spindle braiding machine are set as follows: the braiding pitch is 75-1500 mm; the number of braiding spindles is greater than 14 spindles; and the braiding speed is 600-1000 m / s.
5. The preparation method according to any one of claims 1 to 4, characterized in that: In step 4), the core-spun yarn pre-set sleeve is cured through a curing mandrel; The temperature of curing in the curing core mold is 360-380° C., and the material is pulled out from the curing core mold at a speed of 40-60 mm / min.
6. The preparation method according to claim 5, characterized in that: The curing core mold includes a sheet, a prism, a cylinder or an elliptical cylinder.
7. Thermoplastic carbon fiber woven reinforced composite material prepared by the preparation method according to any one of claims 1 to 6.