Woven covering yarn and preparation method and application thereof

Abstract

The invention discloses a woven covering yarn and a preparation method and application thereof. The woven covering yarn is prepared by weaving and covering a plurality of yarns on the surface of a high-strength fiber core yarn; the high-strength fiber core yarn comprises a core yarn and a resin coating layer, and the resin coating layer is coated on the surface of the core yarn; a resin material selected from the resin coating layer is selected from at least one of polyether-ether-ketone, nylon and polypropylene. The preparation method of the woven core-spun yarn comprises the following steps: 1) impregnating the core yarn in a resin sizing agent and a resin sizing agent, and carrying out pre-impregnation treatment to obtain the high-strength fiber core yarn; 2, the surface of the high-strength fiber core yarn is covered with the yarn through a multi-spindle knitting machine, and then the knitted covering yarn is obtained.In-situ full covering of core yarn fibers is achieved through the knitting covering technology, and the core yarn is protected and enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of textile technology and composite materials, and relates to a braided core-spun yarn and a preparation method and application thereof. Background Art

[0002] Fiber-reinforced composites have been widely used in defense, aerospace, sports and leisure due to their high strength-to-weight ratio, high production efficiency, high damage tolerance, recyclability, weldability and long service life at high temperatures. Traditional fiber-reinforced composites are usually made by pre-impregnating unidirectional fibers with resin and then curing them at high temperatures. Although these materials have excellent performance, the preforms are bulky, have low flexibility and are easy to delaminate, making them inconvenient to store and transport. In addition, the manufacturing cost of pre-impregnated composite preforms is high and time-consuming, their in-plane shear strength and interlaminar shear strength are low, their impact toughness and thickness stiffness are low, and their design flexibility is limited.

[0003] With the development of composite material processing technology, weaving technology has gradually become an important candidate process for the manufacture of fiber-reinforced polymer composites. Weaving technology uses a weaving machine to interweave fibers along a serpentine or circular path, and the bobbin pulls the free end of the fiber at a controllable speed to form a structurally stable woven preform. Compared with traditional unidirectional fiber laminated composites, woven composites are superior in mechanical properties, impact resistance and flexibility. Due to the specific distribution of yarns in the microstructure, woven structural composites have excellent mechanical properties, and the integrated reinforcement structure of multi-directional fibers fundamentally overcomes the fatal weaknesses of layered composites, such as low interlaminar strength and easy delamination. Multi-directional fiber composites exhibit high specific strength, large specific modulus, high impact resistance and tolerance, and can form complex configurations. Due to these advantages, woven structural composites have been widely used in high-tech industries such as automobiles and aerospace. However, despite the significant advantages of woven composites, there is still a problem of difficulty in resin impregnation in their production, especially in multi-layer woven structures. Since the weaving, impregnation and curing processes need to be repeated, it is easy to cause low resin content inside the fiber bundle, uneven resin distribution, and weak interlaminar bonding, which affects the overall performance of the material. Summary of the invention

[0004] The purpose of the invention is to provide a braided core-spun yarn and a preparation method and application thereof.

[0005] The present invention provides a braided core-spun yarn, which is made by braiding and covering a plurality of yarns on the surface of a high-strength fiber core yarn; The high-strength fiber core yarn comprises a core yarn and a resin coating layer, wherein the resin coating layer is coated on the surface of the core yarn; the resin material selected for the resin coating layer is selected from at least one of polyetheretherketone (PEEK for short), nylon and polypropylene.

[0006] In the above-mentioned braided core-spun yarn, the material of the core yarn is selected from at least one of carbon fiber, glass fiber and basalt fiber.

[0007] In the present invention, the thickness of the resin coating layer is determined by the required resin content of the braided core-spun yarn, and the thickness and number of the required yarn are calculated based on the required resin content.

[0008] In the above-mentioned braided core-spun yarn, the material of the yarn is selected from at least one of polyetheretherketone (PEEK), nylon and polypropylene.

[0009] In the above-mentioned braided core-spun yarn, the number of the yarns can be 4 to 16, and the total number can be 8.

[0010] The present invention also provides a method for preparing the above-mentioned braided core-spun yarn, comprising the following steps: 1) impregnating the core yarn in a resin sizing agent and a resin slurry for pre-impregnation to obtain the high-strength fiber core yarn; 2) Using a multi-spindle braiding machine, the yarn is covered on the surface of the high-strength fiber core yarn to obtain the braided core-spun yarn.

[0011] In the above preparation method, the resin sizing agent includes at least one of ethylene-methyl acrylate-glycidyl methacrylate, cyclohexanone, and polyetheretherketone in dichloromethane solution, and different types of the resin sizing agent are selected according to the type of resin used; 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; The devices used for the prepreg treatment are fixed in the order of an unwinder, a tension controller, a drying drum, a sizing tank, an impregnation tank, a winder 8 and a plurality of yarn guide rollers; The sizing agent is added to the sizing tank, the resin slurry is added to the impregnation tank, the temperature of the drying cylinder can be set to 150-400° C., the output tension of the tension controller can be 1.5-3N, and the rotation speed of the winder can be set to 0.2-0.4 m / s.

[0012] In the above preparation method, the parameters of the multi-spindle braiding machine are set as follows: the weaving mesh number can be 5~7 meshes (weaving pitch is 5~15mm), the weaving speed can be 30~50m / h, the weaving angle is jointly regulated by the weaving mesh number and the weaving speed, and the number of weaving spindles can be 4~16 spindles, specifically 4 spindles, 8 spindles or 16 spindles.

[0013] The present invention has the following beneficial effects: 1. Core yarn fiber protection and enhancement The present invention realizes in-situ full coverage of the core yarn fiber through the braiding coating technology, which has a protective and reinforcing effect on the core yarn. For example, it avoids the phenomenon of carbon fiber breakage and carbon filament dispersion in the traditional wrapping process, effectively protects the integrity of the fiber, and avoids local stress concentration, which significantly improves the mechanical properties and safety of the material.

[0014] 2. Improve coverage and reduce stress concentration The present invention adopts a multi-spindle weaving method (such as 4 spindles, 8 spindles or 16 spindles) to evenly interweave multiple strands of coated wires on the surface of high-strength fibers to achieve complete coating of the core yarn. Compared with the traditional Z-twist or S-twist method, the coating rate is greatly improved, local stress concentration is avoided, and damage to the core yarn is reduced. Through this weaving technology, the core yarn is better protected during processing and use, and the mechanical properties, impact resistance and stability of the core-spun yarn are significantly improved. At the same time, the core-spun yarn has excellent weaving performance and is suitable for a wider range of weaving applications.

[0015] 3. Improve the balance between flexibility and strength The high-resin-content braided core-spun yarn developed by the present invention has high strength and stability while maintaining high flexibility. The yarn with this structure can be curled, wound and bent, and its operability is greatly enhanced, which solves the problem of insufficient flexibility of traditional high-strength fiber materials, expands its application range, and reduces storage and transportation costs.

[0016] 4. Break through the limitation of high-strength fiber being difficult to weave The invention effectively solves the technical bottleneck that high-strength fiber materials such as carbon fiber and glass fiber are difficult to weave, knit and braid in traditional processes. Through the improved braiding and coating process, the high-strength fiber / resin core-spun yarn of the invention can be directly used for braiding and weaving, which broadens the application prospects of these materials, especially in industries such as aerospace and automobiles that have high requirements for material performance.

[0017] 5. Performance improvement after high temperature curing The core-spun yarn of the present invention can be transformed from a flexible material to a rigid material through high-temperature curing, and the resin of the cured yarn is evenly distributed, further improving the durability, rigidity and strength of the material. Compared with the traditional process, the present invention ensures the uniform distribution and all-round enhancement of the resin, greatly improving the overall mechanical properties and service life of the material.

[0018] 6. Solve the problem of uneven prepreg material impregnation The core-spun yarn of the present invention can effectively replace the traditional prepreg material, and overcomes the common problem of uneven resin impregnation in the prepreg material. Based on the high-strength fiber / resin core-spun yarn of the present invention, it can be woven into a single-layer or multi-layer integrated fabric structure through a weaving molding process. From the overall point of view, the resin is evenly distributed in the fabric. Thereby improving the manufacturing quality and production efficiency of the composite material, reducing the defects generated in the production process, and improving the overall performance of the final product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of pre-impregnating resin into high-strength fibers in the thermoplastic high-strength fiber braided core-spun yarn with high resin content of the present invention.

[0020] Figure 2 The present invention is a schematic diagram of the high-resin-content thermoplastic high-strength fiber braided core-spun yarn and its preparation process.

[0021] Figure 3 This is a physical picture of the carbon fiber / polyetheretherketone braided core-spun yarn in Example 1 of the present invention.

[0022] Among them, 1 unwinder; 2 high-strength fiber; 3 tension controller; 4 yarn guide roller; 5 drying cylinder; 6 sizing tank; 7 impregnation tank; 8 winder; 9 core yarn tube; 10 polyetheretherketone yarn; 11 resin yarn tube; 12 tube placement table; 13 high-strength fiber preimpregnated yarn. DETAILED DESCRIPTION

[0023] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0024] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0025] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0026] Example 1 This embodiment provides a carbon fiber / polyetheretherketone braided core-spun yarn, such as Figure 3 As shown, the carbon fiber / polyetheretherketone core-spun yarn includes one 3k / T700 continuously pre-impregnated carbon fiber (as a high-strength fiber) located in the center of the yarn and eight 238 D / 30 F polyetheretherketone filaments woven and wrapped on the surface. The coverage of the core-spun yarn is as high as over 99%, and the tensile strength is as high as over 200 MPa.

[0027] The method for preparing the carbon fiber / polyetheretherketone braided core-spun yarn comprises the following steps: According to the requirements of carbon fiber prepreg method, such as Figure 1 As shown, a 3k / T700 carbon fiber (CF for short) yarn is fixed in the high-strength fiber prepreg system in the order of unwinder 1, tension controller 3, drying drum 5, sizing tank 6, impregnation tank 7, winder 8 and multiple yarn guide rollers 4. The modified PEEK sizing agent with carboxyl group is added to the sizing tank 6, and the evenly dispersed PEEK turbid liquid is added to the impregnation tank 7. The temperature of the drying drum 5 is set to 400°C, the output tension of the tension controller 3 is 1.5N, and the speed of the winder 8 is set to 0.2m / s. The carbon fiber prepreg process is carried out to obtain the high-strength fiber prepreg yarn.

[0028] like Figure 2 As shown, a 238D / 30F polyetheretherketone (PEEK) yarn 10 is wound on a resin yarn tube 11 of a braiding machine at a constant tension using a wire splitting machine, and the winding parameters are: a winding speed of 2000 rpm, a line arrangement speed of 100 rpm, and a yarn length of 1500 m.

[0029] The carbon fiber (i.e., high-strength fiber prepreg yarn 13) after the above prepreg process is used as the core wire, which is placed on the core yarn tube 9, and the PEEK yarn 10 is used as the covering wire. Eight resin yarn tubes 11 wrapped with PEEK yarn (i.e., polyetheretherketone yarn 10) are equipped on the tube placement table 12 of the braiding machine to prepare the braided core yarn. The parameters of the braiding machine are set as follows: braiding mesh: 7 mesh, braiding speed: 50m / h, and braiding spindle number: 8 spindles.

[0030] The braided core-spun yarn (referred to as carbon fiber-polyetheretherketone in Table 1) prepared by the above method is as follows: Figure 3 shown.

[0031] Embodiment 2-4, The yarns were prepared according to the method in Example 1 of the present invention, except that carbon fiber was used as the core yarn, and nylon 66, polypropylene, and polyetheretherketone were used respectively (wherein the number of spindles prepared is shown in Table 1), to obtain carbon fiber-nylon 66 braided core-spun yarn, carbon fiber-polypropylene braided core-spun yarn, and carbon fiber-polyetheretherketone braided core-spun yarn, respectively, as recorded in Table 1 as carbon fiber-nylon 66, carbon fiber-polypropylene, and carbon fiber-polyetheretherketone.

[0032] Embodiment 5-7, The carbon fiber-nylon yarn was prepared according to the method in Example 1 of the present invention, except that glass fiber core yarn was used, and the yarns were made of polypropylene and nylon (the number of spindles prepared was shown in Table 1). dragon 66 braided core-spun yarns, as recorded in Table 1 as glass fiber-polypropylene, glass fiber-nylon, and glass fiber-polyetheretherketone.

[0033] The performance data of the braided core-spun yarn, carbon fiber and glass fiber prepared in the above Examples 1-7 are shown in Table 1.

[0034] Table 1

[0035] According to Table 1, by comparing the performance data of Examples 1-4 with that of carbon fiber, it can be seen that the density of the carbon fiber-resin core-spun yarn is between the density of carbon fiber and resin yarn. It has better mechanical properties than carbon fiber and also has better elongation at break. Even though the drape of the core-spun yarn is slightly reduced, it is still above 81%, proving that the carbon fiber-resin core-spun yarn of the present invention has good flexibility. As the selected resin yarn changes, its mechanical properties also change accordingly. The tensile strength is specifically presented as carbon fiber-polyetheretherketone>carbon fiber-nylon 66>carbon fiber-polypropylene, and the elongation at break is specifically presented as carbon fiber-nylon 66>carbon fiber-polypropylene>carbon fiber-polyetheretherketone. The drape is reflected as carbon fiber-polypropylene>carbon fiber-nylon 66>carbon fiber-polyetheretherketone. As the number of weaving spindles used in the core-spun yarn increases, the tensile strength and elongation at break of the core-spun yarn gradually increase, and the drape gradually decreases; By comparing the performance data of Examples 5-7 with glass fiber, it can be seen that when using the same resin yarn and the same number of braided spindles, the glass fiber-resin core-spun yarn has a higher density, lower tensile strength, higher elongation at break and higher drape than the carbon fiber resin core-spun yarn. The density of the glass fiber-resin core-spun yarn is between the density of the glass fiber and the resin yarn. While having better mechanical properties than the glass fiber, it also has a better elongation at break. Even if the drape of the core-spun yarn is slightly reduced, it is still above 82%, proving that the glass fiber-resin core-spun yarn has good flexibility. With the change of the selected resin yarn, its mechanical properties also change accordingly, and the tensile strength is specifically presented as glass fiber-polyetheretherketone>glass fiber-nylon 66>glass fiber-polypropylene, and the elongation at break is specifically presented as glass fiber-nylon 66>glass fiber-polypropylene>glass fiber-polyetheretherketone, and the drape is embodied as glass fiber-polypropylene>glass fiber-nylon 66>glass fiber-polyetheretherketone. With the increase of the number of weaving spindles used in the core-spun yarn, the tensile strength and elongation at break of the core-spun yarn gradually increase, and the drape gradually decreases.

[0036] The applicant declares that the above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A braided core-spun yarn, characterized in that: The braided core-spun yarn comprises a plurality of yarns which are braided and coated on the surface of a high-strength fiber core yarn; The high-strength fiber core yarn comprises a core yarn and a resin coating layer, wherein the resin coating layer is coated on the surface of the core yarn; the resin material selected for the resin coating layer is selected from at least one of polyetheretherketone, nylon and polypropylene.

2. The braided core-spun yarn according to claim 1, characterized in that: The material of the core yarn is selected from at least one of carbon fiber, glass fiber and basalt fiber.

3. The braided core-spun yarn according to claim 1 or 2, characterized in that: The material of the yarn is selected from at least one of polyetheretherketone, nylon and polypropylene.

4. The braided core-spun yarn according to any one of claims 1 to 3, characterized in that: The number of the yarns is 4 to 16.

5. The method for preparing the braided core-spun yarn according to any one of claims 1 to 4, comprising the following steps: 1) impregnating the core yarn in a resin sizing agent and a resin slurry for pre-preg treatment to obtain the high-strength fiber core yarn; 2) Using a multi-spindle braiding machine, the yarn is covered on the surface of the high-strength fiber core yarn to obtain the braided core-spun yarn.

6. The preparation method according to claim 5, characterized in that: The resin sizing agent includes at least one of ethylene-methyl acrylate-glycidyl methacrylate, cyclohexanone, and polyetheretherketone in dichloromethane solution; The devices used for the prepreg treatment are fixed in the order of an unwinder, a tension controller, a drying drum, a sizing tank, an impregnation tank, a winder 8 and a plurality of yarn guide rollers; The sizing agent is added to the sizing tank, the resin slurry is added to the impregnation tank, the temperature of the drying cylinder is set to 150-400° C., the output tension of the tension controller is 1.5-3N, and the rotation speed of the winder is set to 0.2-0.4 m / s.

7. The preparation method according to claim 5 or 6, characterized in that: The parameters of the multi-spindle braiding machine are set as follows: the braiding mesh number is 5 to 9 meshes, the braiding speed is 30 to 50 m / h, and the number of braiding spindles is 4 to 16 spindles.

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