A continuous yarn for winding molding, its production process and application

Abstract

The present invention belongs to the technical field of processing and treatment of high-performance fiber materials and their composites, and relates to a continuous yarn for winding molding, its production process and application. The production process includes a mixing and opening process, a carding process, a sizing process, a gathering process, a drawing process, and a twisting process; there is one sizing process in total, and the spraying method is adopted; alternatively, there are two sizing processes in total, the first one adopts the spraying method, and the second one adopts the impregnation method; drying is carried out while gathering; the continuous yarn for winding molding is prepared by this production process; the application is to impregnate the continuous yarn for winding molding into a resin matrix, wind it onto a core mold, then carry out heating and curing molding, and then cool and demold to obtain a unidirectional fiber winding reinforced composite material. By innovating the sizing process, the present invention successfully manufactures a continuous yarn for winding molding from discontinuous high-performance fibers, solves its application limitations, and realizes the high-value recycling and reuse of high-performance fibers.

Description

Technical Field

[0001] The present invention belongs to the technical field of processing and treatment of high-performance fiber materials and their composites, and relates to a continuous yarn for winding molding, its production process and application. Background Art

[0002] High-performance fibers represented by carbon fibers have excellent properties such as high specific strength, high specific modulus, and corrosion resistance. Their physical properties are superior to traditional metal materials in many aspects and are widely used in fields such as aviation, energy, transportation, construction, and military industry, and are an important part of advanced composites. However, the production process of high-performance fibers consumes a large amount of energy. Recycling and reusing them can not only reduce energy consumption and manufacturing costs, but also give full play to the mechanical property advantages of recycled fibers. However, due to the limitation of the recycling process, the recycled high-performance fibers are usually in a non-continuous form. Since non-continuous high-performance fibers are not suitable for the molding process of continuous fiber reinforced resin matrix composites including winding molding, their application value is severely limited and they cannot give full play to the performance advantages of high-performance fibers. Therefore, it is urgent to explore a process method to make non-continuous high-performance fibers into continuous yarns, and then use the winding process for molding to realize the high-value application of non-continuous high-performance fibers and turn waste into treasure.

[0003] In order to make non-continuous high-performance fibers into continuous yarns, non-continuous high-performance fibers and thermoplastic resin fibers can be blended into yarns (this blended yarn is denoted as blended yarn X). During the preparation of the yarn sliver, the fibers will separate and rearrange, and the adhesion between the fibers will directly cause fiber breakage during the carding process, reducing the fiber length in the yarn sliver and increasing the content of impurities such as neps, resulting in poor quality of the yarn sliver. Therefore, during the preparation of the yarn sliver, before carding, the surface of the non-continuous high-performance fibers needs to be desized to keep it clean to ensure the smooth forming of the yarn sliver. However, the clean non-continuous high-performance fibers after removing the surface sizing agent are chemically inert on the surface. If such surface-treated high-performance fibers and the products prepared therefrom are directly used for the winding molding composite sample to reinforce the thermosetting resin matrix, due to the poor interfacial bonding performance with the thermosetting resin matrix, the performance of the sample will be insufficient and cannot meet the product requirements of the current winding molding composite sample. Therefore, a suitable surface modification process needs to be adopted to treat the fibers after carding, that is, the blended yarn X.

[0004] Sizing is a common surface modification process, which can form an organic substance on the fiber surface to improve the bonding effect between the fiber and the resin. Compared with other surface modification processes such as plasma treatment and chemical grafting, the sizing process has the advantages of simple process, low cost, fiber protection, improved processing performance, and easier industrial application.

[0005] There are existing technologies for sizing continuous high-performance fibers, but it is difficult to apply these technologies to sizing blended yarn X for the following reasons:

[0006] At present, the sizing technology of continuous high-performance fibers includes traditional impregnation, distributed sizing and spray sizing (CN213357961U) and other methods. These methods all use a certain tension to apply to the continuous high-performance fibers to flatten them and then perform continuous sizing. The specific process is: after applying tension to flatten the continuous high-performance fiber tow, it is immersed in the sizing liquid in the dipping tank, or the atomized sizing liquid is sprayed on the fiber surface to fully infiltrate the fiber tow with the sizing liquid. After the fiber tow leaves the dipping tank, the excess sizing liquid is removed by a scraper or a rubber roller to control the sizing rate, and finally dried.

[0007] However, in the sizing process of continuous high-performance fibers, the fibers need to be flattened by tension to achieve uniform sizing. However, when the product to be sized is a blended yarn X, its structure is formed by the entanglement and overlap of non-continuous high-performance fibers, which cannot be flattened by tension. If the blended yarn X is sized according to the sizing process of continuous high-performance fibers, the applied tension will destroy the overall structure of the yarn, resulting in the loosening and damage of the fiber yarn and the unwrapped fiber roving structure, which is very easy to break the yarn or break the strip.

[0008] The prior art has sizing for blended yarns other than blended yarn X (the blended yarn is denoted as blended yarn Y), but it is difficult to sizing for blended yarn X by referring to these technologies for the following reasons:

[0009] At present, the sizing technology of blended yarn Y includes solution impregnation method, foam sizing method and sizing extrusion method (CN117535897A), etc. These processes are mature and stable. These methods are all for sizing the yarn after twisting and forming. The specific process is: immersing the twisted yarn in sizing liquid or sizing foam, or using a roller to bring up the sizing liquid and then apply it to the twisted yarn, and then drying to complete the sizing. The purpose of sizing the blended yarn Y is to improve the wear resistance of the yarn, so that the sizing liquid penetrates into the yarn to increase the breaking strength, and prevent the yarn from breaking or pilling in the subsequent textile process. Therefore, the sizing rate is generally controlled at 6% to 12%. The primary purpose of sizing the blended yarn X is to improve the interface performance between the resin matrix and the non-continuous high-performance fiber, and it has a greater impact on the interface performance. The sizing rate is generally below 3%, and it needs to be accurately controlled to one decimal place of the percentage. Its sizing accuracy is much higher than the sizing accuracy of other blended yarns. Since there are large differences in sizing rate and sizing accuracy between blended yarn X and blended yarn Y, the sizing process of blended yarn Y cannot be directly applied to blended yarn X.

[0010] Therefore, it is necessary to study a sizing process for blended yarn X. Summary of the invention

[0011] The object of the present invention is to solve the problems existing in the prior art, provide a sizing process for blended yarn X, and further obtain a production process for continuous yarn for winding molding mainly made of discontinuous high-performance fibers and thermoplastic resin fibers. Further, the obtained continuous yarn for winding molding is applied to the winding field.

[0012] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0013] A production process for continuous yarn for winding molding, including a mixing and opening process, a carding process, a gathering process, a drawing process, and a twisting process;

[0014] Mixing and opening means mixing discontinuous high-performance fibers and thermoplastic resin fibers and then opening them. The surface of the discontinuous high-performance fibers has no sizing agent. The opening method is not limited, and the air flow assisted free opening method can be used. The air flow generated by the fan tumbles in the mixing bin, and the opening roller is combined to loosen the fibers and improve the fluffiness of the fiber mixture;

[0015] During carding, the discontinuous high-performance fibers and thermoplastic resin fibers form a net-like structure attached to the roller after being carded by the cylinder and the working roller in the carding machine, and are peeled off from the doffer by the stripping knife to obtain a continuous and uniform single-layer fiber yarn net;

[0016] Drawing can further improve the orientation degree and uniformity of the discontinuous high-performance fibers in the sliver, reduce the fineness of the sliver to approximately the linear density of the required sliver, as Figure 3 and Figure 4 shown. The arrangement direction of the black carbon fibers inside the sliver before and after drawing is improved from a messy state to an arrangement along the transverse fiber sliver direction. In addition, by adjusting the drawing process parameters, the thickness of the sliver after drawing can be controlled, so as to control the fineness of the final sliver. The number of drawing passes can be increased depending on the product state;

[0017] Twisting can tighten the loose fibers together to form a firm rope-like yarn structure;

[0018] It also includes a sizing process;

[0019] There is a total of one sizing process, which is located between the carding process and the gathering process, and the spraying method is adopted (that is, the sizing solution is sprayed on the yarn net formed by carding using a high-pressure atomizing nozzle); the sizing rate is equal to the set sizing rate, and the set sizing rate is not higher than 3%;

[0020] The timing and method of sizing are both important. If sizing is carried out before carding, regardless of the sizing method used, it will cause bonding between fibers, resulting in breakage and other damages during carding; if spray sizing is carried out after twisting, since the sizing solution stays on the surface of the yarn, it is necessary to rely on the extrusion of rubber pressure rollers to make the sizing solution further penetrate between the fibers, which will cause damage to the fiber and yarn structure; if dip sizing is carried out after twisting, since the yarn will inevitably be affected by factors such as tension and liquid resistance during the process of entering and leaving the sizing solution, the yarn structure is prone to damage. At the same time, sizing the twisted yarn will also lead to uneven sizing and difficulty in accurately controlling the sizing rate due to the complex internal structure of the yarn.

[0021] In the present invention, spray sizing is carried out between the carding process and the gathering process. At this time, the sizing solution can easily penetrate between the fibers, without relying on the extrusion of rubber pressure rollers, which can avoid damage to the fiber and yarn structure, and can make the sizing agent fully and evenly penetrate into the yarn interior on the premise of low loss or no loss.

[0022] Drying is also carried out while gathering.

[0023] The mechanical properties of the molded plate obtained by molding the gathered yarn and epoxy resin are significantly better than those of the molded plate obtained without the sizing process. Thus, it can be seen that spray sizing between the carding process and the gathering process can complete the uniform surface modification work inside and outside the yarn net.

[0024] As a preferred technical solution:

[0025] For the production process of continuous yarn for winding molding as described above, the concentration of the sizing solution used for sizing is 3.5 - 6.5 wt%, so as to ensure the uniformity of the overall sizing of the yarn net. The viscosity is 15 - 45 mPa·s, so as to fully penetrate into the fiber gaps inside the yarn net and form a sizing layer. The spraying rate is positively correlated with the carding speed.

[0026] For the production process of continuous yarn for winding molding as described above, the average length of the discontinuous high-performance fibers is 40 - 200 mm. The discontinuous high-performance fibers are common resin matrix composite reinforcements such as glass fibers, carbon fibers, basalt fibers or boron fibers; the average length of the thermoplastic resin fibers is the same as that of the discontinuous high-performance fibers to ensure uniform mixing of the fibers after opening. The thermoplastic resin fibers are PA fibers, PET fibers, PP fibers, PEEK fibers or PPS fibers; the mass ratio of the discontinuous high-performance fibers to the thermoplastic resin fibers is not limited.

[0027] A production process for continuous yarn used in winding molding as described above. For mixing and opening, an opener is used, with a feeding speed of 0.5 - 2.0 m / min and a rotating speed of the opening beater of 800 - 1500 rpm; for carding, a carding machine is used, with a rotating speed of the cylinder of 100 - 400 rpm, a rotating speed of the doffer of 50 - 200 rpm, and a feeding speed of 0.3 - 1.5 m / min; for drawing, a drawing frame is used, with a draft ratio of 1.5 - 3.0 and a drawing speed of 50 - 150 m / min; when twisting, the set twist is 20 - 40 T / m and the winding tension is 5 - 15 cN; the fineness of the gathered yarn is 2383 - 4873 tex, and the fineness of the twisted yarn is 426.3 - 488.3 tex.

[0028] The present invention also provides another production process for continuous yarn used in winding molding, including a mixing and opening process, a carding process, a gathering process, a drawing process, and a twisting process;

[0029] Mixing and opening means mixing discontinuous high-performance fibers and thermoplastic resin fibers and then opening them. There is no sizing agent on the surface of the discontinuous high-performance fibers;

[0030] It also includes a sizing process;

[0031] There are two sizing processes in total. The first sizing process is located between the carding process and the gathering process, and the spraying method is adopted (that is, using a high-pressure atomizing nozzle to spray the sizing solution on the formed card web). The second sizing process is located after the twisting process, and the dipping method is adopted (that is, dipping the yarn in the sizing solution, taking it out, and drying it); the sizing agents used in the two sizing processes are the same. The sizing rate of the first sizing is 60 - 75% of the set sizing rate, and the total sizing rate of the two sizing processes is equal to the set sizing rate, and the set sizing rate is not higher than 3%;

[0032] Drying is carried out while gathering.

[0033] Regardless of whether there is one or two sizing processes, sizing can be carried out by the spraying method between the carding process and the gathering process to complete the uniform surface modification work inside and outside the card web. The advantage of two sizing processes compared to one is that it can improve the finishing quality of the continuous yarn used in winding molding, reduce the number of hairiness on the surface of the continuous yarn used in winding molding, enhance the wear resistance and cohesion of the continuous yarn used in winding molding, and maintain the flexibility of the yarn.

[0034] As a preferred technical solution:

[0035] A production process of continuous yarn for winding molding as described above. The concentration of the sizing solution used in the first sizing process is 3.5 - 6.5 wt%, which can ensure the uniformity of the overall sizing of the yarn mesh. The viscosity is 15 - 45 mPa·s, which can fully penetrate into the fiber gaps of the yarn mesh and form a sizing layer. The spraying rate is positively correlated with the carding speed. The concentration of the sizing solution used in the second sizing process is 1.0 - 2.5 wt%, which can reduce the yarn hairiness, form a wear-resistant layer, and maintain the flexibility of the yarn. The viscosity is 2 - 10 mPa·s. During the second sizing process, the impregnation temperature is 35 - 60 °C and the impregnation time is 5 - 20 s.

[0036] A production process of continuous yarn for winding molding as described above further includes a wrapping process located between the twisting process and the second sizing process. Wrapping means wrapping continuous fibers around the yarn formed by twisting. Wrapping can improve the strength, uniformity, and wear resistance of the yarn. If the second sizing is directly carried out after twisting and ends after the second sizing, the obtained continuous yarn for winding molding cannot ensure that it can always withstand a large tension.

[0037] A production process of continuous yarn for winding molding as described above. The continuous fiber is a small tow continuous fiber with a fineness of 20 - 150 D. Optional fibers include carbon fiber, glass fiber, and various organic fibers, which are selected according to the process requirements. During wrapping, the wrapping speed is 50 - 200 m / min, the wrapping angle is 15 - 35°, the wrapping tension is 5 - 20 cN, and the wrapping twist is 200 - 800 T / m.

[0038] The present invention also provides a continuous yarn for winding molding, which is prepared by using a production process of continuous yarn for winding molding as described in any one of the above.

[0039] The present invention also provides an application of the continuous yarn for winding molding as described above. After impregnating the continuous yarn for winding molding with a resin matrix, it is wound onto a mandrel, and then heated and cured to form a shape, and then cooled and demolded to obtain a unidirectional fiber winding reinforced composite material.

[0040] The continuous yarn for winding molding prepared by the present invention can be applied to the winding field. In winding process structures with lower load-bearing requirements and lower requirements, the continuous yarn for winding molding is used to replace continuous long fibers for winding molding, thereby solving the problem in the prior art that the utilization value of non-continuous high-performance fibers is relatively low and it is difficult to be applied to high-performance structural parts. At the same time, it provides higher designability for the winding process, reduces the preparation cost and carbon emissions of the winding process. The continuous yarn for winding molding contains thermoplastic resin fibers, which is beneficial to improving the interlayer toughness and impact resistance of the product. In addition, applying the continuous yarn for winding molding to winding has a high degree of process automation, saves labor, has a high raw material utilization rate, and can maximize the value of the continuous yarn for winding molding.

[0041] Beneficial effects:

[0042] (1) In the present invention, non - continuous high - performance fibers are spray - sized between the carding process and the gathering process, which can avoid damage to the fiber and yarn structure. On the premise of low - loss or no - loss, uniform surface modification work inside and outside the yarn net is realized, improving the interfacial properties between the high - performance fibers and the resin matrix in the yarn during the subsequent forming process, enhancing the overall mechanical properties of the continuous yarn for winding forming, and expanding the use value and application range of the continuous yarn product for winding forming;

[0043] (2) In the present invention, the continuous yarn for winding forming is impregnated and sized after the twisting process, which can improve the finishing quality of the continuous yarn for winding forming, reduce the number of hairiness on the surface of the continuous yarn for winding forming, enhance the abrasion resistance and cohesion of the continuous yarn for winding forming, and maintain the flexibility of the yarn;

[0044] (3) The fiber type, fiber content of the continuous yarn for winding forming in the present invention, and the fineness of the continuous yarn for winding forming are all controllable;

[0045] (4) By performing specific processes such as opening, carding, gathering, drawing, and twisting on non - continuous high - performance fibers, the present invention greatly improves the orientation degree and uniformity of non - continuous high - performance fibers in the continuous yarn for winding forming, making the yarn product have excellent modulus performance, thereby effectively enhancing the application value of non - continuous high - performance fibers;

[0046] (5) The continuous yarn for winding forming in the present invention has a low preparation cost and excellent modulus performance. It can be used in the winding field to replace components with lower load - bearing requirements in the winding process, thereby achieving cost reduction, improving toughness and having structural designability, and greatly enhancing the application value of non - continuous high - performance fibers;

[0047] (6) By using the continuous yarn for winding forming for winding forming and introducing thermoplastic resin fibers into the winding formed part, after the winding product is cured, the thermoplastic resin dissolves in the resin matrix in the inter - layer direction, achieving a toughening effect, fully improving the inter - layer fracture toughness of the winding product, and broadening the application of the continuous yarn for winding forming in the winding field. Description of the drawings

[0048] Figure 1 Is a physical picture of the continuous yarn for winding forming prepared in Example 4;

[0049] Figure 2 Is a physical picture of the continuous yarn for winding forming prepared in Example 3;

[0050] Figure 3 Is a super - depth - of - field image of the yarn strip gathered in Example 3, with a resolution of 1471×1099;

[0051] Figure 4 It is the super-depth-of-field image of the sliver obtained in drawing in Example 3, with a resolution of 1471×1099. Specific embodiments

[0052] 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.

[0053] The following are the test methods for relevant performance indicators in each example and comparative example:

[0054] Viscosity: Tested in accordance with the standard of GB / T 22235-2008.

[0055] Tensile strength at 0°, tensile modulus at 0°: Tested in accordance with the standard of ISO527-5:2021.

[0056] Compressive strength at 0°, compressive modulus at 0°: Tested in accordance with the standard of ISO14126:2023.

[0057] Flexural strength at 0°, flexural modulus at 0°: Tested in accordance with the standard of ISO14125:1998.

[0058] Fiber mass content, fiber volume content: The unidirectional fiber winding reinforced composites prepared in Examples 1-3 are tested in accordance with the standard of ISO 14127:2024, the unidirectional fiber winding reinforced composites prepared in Examples 4-5 are tested in accordance with the standard of ISO1172:2023, and the sliver obtained by gathering in Examples 5 and Comparative Example 1 and the molded plate obtained by compression molding with epoxy resin are tested in accordance with the standard of ISO 1172:2023.

[0059] Density: Tested according to ISO1183-1:2019.

[0060] Tensile strength, tensile modulus, fiber tensile strength, fiber tensile modulus: Tested in accordance with the standard of GB / T 1458-2023, where the loading speed is 2mm / min.

[0061] Example 1

[0062] A preparation method of a unidirectional fiber winding reinforced composite material, the specific steps are as follows:

[0063] (1) Preparation of raw materials;

[0064] Discontinuous high-performance fibers: carbon fibers, manufactured by Toray Industries, Inc., grade T700, average length 120 mm;

[0065] Thermoplastic resin fibers: PA56 fibers, manufactured by Shanghai Kaisai Biotechnology Co., Ltd., grade T-1105, average length 120 mm;

[0066] Sizing solution A: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., grade MH-681), the solvent is deionized water, the concentration is 3.5 wt%, and the viscosity is 15 mPa·s;

[0067] Sizing solution B: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., grade MH-681), the solvent is deionized water, the concentration is 2.5 wt%, and the viscosity is 10 mPa·s;

[0068] Continuous fibers: Small tow continuous fibers with a fineness of 150 D;

[0069] Resin matrix: Epoxy resin, manufactured by Swancor Advanced Materials Co., Ltd., grade EzCicloRB241;

[0070] (2) Prepare continuous yarns for filament winding molding;

[0071] The production process of continuous yarns for filament winding molding is: mixing and opening → carding → first sizing → gathering → drawing → twisting → wrapping → second sizing;

[0072] Mixing and opening means using an opener to mix and open the discontinuous high-performance fibers and thermoplastic resin fibers. The mass ratio of the discontinuous high-performance fibers to the thermoplastic resin fibers is 2:1, the feeding speed is 0.5 m / min, and the speed of the opening beater is 800 rpm;

[0073] Carding is carried out using a carding machine. The speed of the cylinder is 100 rpm, the speed of the doffer is 50 rpm, and the feeding speed is 0.3 m / min;

[0074] In the first sizing process, sizing solution A is used and the spraying method is adopted. The sizing rate of the first sizing is 60% of the set sizing rate; in the second sizing process, sizing solution B is used and the impregnation method is adopted. The impregnation temperature is 35 °C and the impregnation time is 20 s; the total sizing rate of the two sizings is equal to the set sizing rate, and the set sizing rate is 1.7%;

[0075] Drying is also carried out during gathering; the fineness of the yarn strip obtained by gathering is 2383 tex;

[0076] Drawing is carried out using a draw frame, the draft ratio is 1.5, and the drawing speed is 50 m / min;

[0077] During twisting, the set twist is 20 T / m, the winding tension is 5 cN, and the fineness of the yarn formed by twisting is 488.3 tex;

[0078] Wrapping means continuously wrapping fibers around the yarn formed by twisting. The wrapping speed is 50 m / min, the wrapping angle is 15°, the wrapping tension is 15 cN, and the wrapping twist is 200 T / m;

[0079] (3)Prepare unidirectional fiber-wound reinforced composite materials;

[0080] After impregnating the continuous yarn for winding molding with a resin matrix, wind it (the relevant process parameters are set according to the GB / T 1458-2023 standard) onto a mandrel, then carry out temperature rise and curing molding, and finally cool and demold to obtain unidirectional fiber-wound reinforced composite materials.

[0081] The final unidirectional fiber-wound reinforced composite material has a fiber mass content of 48.21%, a fiber volume content of 38.29%, a fiber tensile strength of 936.80 MPa, a fiber tensile modulus of 142.20 GPa, and a density of 1.38 g / cm 3 , with a tensile strength of 358.70 MPa and a tensile modulus of 54.45 GPa.

[0082] Example 2

[0083] A method for preparing unidirectional fiber-wound reinforced composite materials, the specific steps are as follows:

[0084] (1)Preparation of raw materials;

[0085] Discontinuous high-performance fibers: carbon fibers, manufactured by Toray Industries, Inc., with a grade of T700 and an average length of 120 mm;

[0086] Thermoplastic resin fibers: PA56 fibers, manufactured by Shanghai Kaisai Biotechnology Co., Ltd., with a grade of T-1105 and an average length of 120 mm;

[0087] Sizing solution A: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., with a grade of MH-681), the solvent is deionized water, the concentration is 6.5 wt%, and the viscosity is 45 mPa·s;

[0088] Sizing solution B: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., with a grade of MH-681), the solvent is deionized water, the concentration is 1.0 wt%, and the viscosity is 2 mPa·s;

[0089] Continuous fibers: small tow continuous fibers with a fineness of 60 D;

[0090] Resin matrix: Epoxy resin, manufactured by Swancor Advanced Materials Co., Ltd., with the grade of EzCicloRB241;

[0091] (2)Prepare continuous yarn for filament winding molding;

[0092] The production process of continuous yarn for filament winding molding is: mixing and opening → carding → first sizing → gathering → drawing → twisting → wrapping → second sizing;

[0093] Mixing and opening means using an opener to mix and open the discontinuous high-performance fibers and thermoplastic resin fibers. The mass ratio of discontinuous high-performance fibers to thermoplastic resin fibers is 3:1, the feeding speed is 1 m / min, and the speed of the opening beater is 1200 rpm;

[0094] Carding is carried out using a carding machine. The speed of the cylinder is 250 rpm, the speed of the doffer is 150 rpm, and the feeding speed is 0.7 m / min;

[0095] In the first sizing process, sizing solution A is used and the spraying method is adopted. The sizing rate of the first sizing is 70% of the set sizing rate; in the second sizing process, sizing solution B is used and the impregnation method is adopted. The impregnation temperature is 60 °C and the impregnation time is 5 s; the total sizing rate of the two sizings is equal to the set sizing rate, and the set sizing rate is 1.7%;

[0096] Drying is also carried out during gathering; the fineness of the yarn strip obtained by gathering is 4247 tex;

[0097] Drawing is carried out using a drawframe, with a draft ratio of 3 and a drawing speed of 120 m / min;

[0098] When twisting, the set twist is 30 T / m, the winding tension is 12 cN, and the fineness of the yarn formed by twisting is 476.2 tex;

[0099] Wrapping means wrapping continuous fibers around the yarn formed by twisting. The wrapping speed is 150 m / min, the wrapping angle is 25°, the wrapping tension is 20 cN, and the wrapping twist is 800 T / m;

[0100] (3)Prepare unidirectional fiber-wound reinforced composite materials;

[0101] After impregnating the continuous yarn for filament winding molding with the resin matrix, it is wound (the relevant process parameters are set according to the GB / T 1458-2023 standard) onto the core mold, and then after heating and curing molding, it is cooled and demolded to obtain unidirectional fiber-wound reinforced composite materials.

[0102] The fiber mass content of the finally obtained unidirectional fiber-wound reinforced composite material is 45.12%, the fiber volume content is 35.40%, the fiber tensile strength is 1025.26 MPa, the fiber tensile modulus is 151.98 GPa, and the density is 1.41 g / cm 3 , the tensile strength is 372.50 MPa, and the tensile modulus is 53.80 GPa.

[0103] Example 3

[0104] A preparation method of a unidirectional fiber-wound reinforced composite material is as follows:

[0105] (1) Preparation of raw materials;

[0106] Discontinuous high-performance fibers: carbon fibers, manufactured by Toray Industries, Inc., with a grade of T700 and an average length of 80 mm;

[0107] Thermoplastic resin fibers: PA56 fibers, manufactured by Shanghai Kaisai Biotechnology Co., Ltd., with a grade of T-1105 and an average length of 80 mm;

[0108] Sizing solution A: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., with a grade of MH-681), the solvent is deionized water, the concentration is 6.0 wt%, and the viscosity is 37 mPa·s;

[0109] Sizing solution B: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., with a grade of MH-681), the solvent is deionized water, the concentration is 1.0 wt%, and the viscosity is 2 mPa·s;

[0110] Continuous fibers: small tow continuous fibers with a fineness of 20 D;

[0111] Resin matrix: epoxy resin, manufactured by Swancor Advanced Materials Co., Ltd., with a grade of EzCicloRB241;

[0112] (2) Preparation of continuous yarns for winding molding;

[0113] The production process of continuous yarns for winding molding is: mixing and opening → carding → first sizing → gathering → drawing → twisting → wrapping → second sizing;

[0114] Mixing and opening means using an opener to mix and open the discontinuous high-performance fibers and thermoplastic resin fibers. The mass ratio of the discontinuous high-performance fibers to the thermoplastic resin fibers is 3:1, the feeding speed is 1 m / min, and the speed of the opening beater is 1200 rpm;

[0115] Carding is carried out using a carding machine. The cylinder speed is 250 rpm, the doffer speed is 150 rpm, and the feeding speed is 0.7 m / min.

[0116] In the first sizing process, sizing solution A is used and the spraying method is adopted. The sizing rate of the first sizing is 70% of the set sizing rate. In the second sizing process, sizing solution B is used and the dipping method is adopted. The dipping temperature is 60 °C and the dipping time is 10 s. The total sizing rate of the two sizings is equal to the set sizing rate, and the set sizing rate is 1.7%.

[0117] During gathering, drying is also carried out. The fineness of the gathered sliver is 4620 tex, and the super-depth-of-field image of the gathered sliver is as Figure 3 shown;

[0118] Drawing is carried out using a drawing frame. The draft ratio is 3, the drawing speed is 120 m / min, and the super-depth-of-field image of the drawn sliver is as Figure 4 shown;

[0119] During twisting, the set twist is 30 T / m, the winding tension is 12 cN, and the fineness of the twisted yarn is 426.3 tex.

[0120] For covering, continuous fibers are covered on the twisted yarn. The covering speed is 150 m / min, the covering angle is 25°, the covering tension is 20 cN, and the covering twist is 800 T / m.

[0121] The physical object of the obtained continuous yarn for winding molding is as Figure 2 shown;

[0122] (3) Prepare unidirectional fiber-wound reinforced composite materials;

[0123] After impregnating the continuous yarn for winding molding with a resin matrix, it is wound (the relevant process parameters are set according to the GB / T 1458-2023 standard) onto a core mold, and then heated and cured to form, and finally cooled and demolded to obtain unidirectional fiber-wound reinforced composite materials.

[0124] The final obtained unidirectional fiber-wound reinforced composite material has a fiber mass content of 46.87%, a fiber volume content of 37.03%, a fiber tensile strength of 1056.85 MPa, a fiber tensile modulus of 137.27 GPa, a density of 1.35 g / cm 3 , a tensile strength of 391.35 MPa, and a tensile modulus of 50.83 GPa.

[0125] Example 4

[0126] A preparation method of unidirectional fiber-wound reinforced composite materials, the specific steps are as follows:

[0127] (1) Preparation of raw materials;

[0128] Discontinuous high-performance fibers: glass fibers, manufactured by Zhejiang Hengshi Industry Co., Ltd., grade E8-UD1250, average length 80 mm;

[0129] Thermoplastic resin fibers: PA56 fibers, manufactured by Shanghai Kaisai Biotechnology Co., Ltd., grade T-1105, average length 80 mm;

[0130] Sizing solution A: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., grade MH-681), the solvent is deionized water, the concentration is 6.0 wt%, and the viscosity is 37 mPa·s;

[0131] Sizing solution B: The solute is a sizing agent (manufactured by Changsha Xindehang Chemical Co., Ltd., grade MH-681), the solvent is deionized water, the concentration is 2.0 wt%, and the viscosity is 6 mPa·s;

[0132] Continuous fibers: small tow continuous fibers with a fineness of 20 D;

[0133] Resin matrix: epoxy resin, manufactured by Swancor Advanced Materials Co., Ltd., grade EzCicloRB241;

[0134] (2) Preparation of continuous yarns for filament winding molding;

[0135] The production process of continuous yarns for filament winding molding is: mixing and opening → carding → first sizing → gathering → drawing → twisting → wrapping → second sizing;

[0136] Mixing and opening means using an opener to mix and open the discontinuous high-performance fibers and thermoplastic resin fibers. The mass ratio of discontinuous high-performance fibers to thermoplastic resin fibers is 9:1, the feeding speed is 2 m / min, and the speed of the opening beater is 1500 rpm;

[0137] Carding is carried out using a carding machine. The speed of the cylinder is 400 rpm, the speed of the doffer is 200 rpm, and the feeding speed is 1.5 m / min;

[0138] In the first sizing process, sizing solution A is used and the spraying method is adopted. The sizing rate of the first sizing is 75% of the set sizing rate; in the second sizing process, sizing solution B is used and the dipping method is adopted. The dipping temperature is 50 °C and the dipping time is 20 s; the total sizing rate of the two sizings is equal to the set sizing rate, and the set sizing rate is 2.8%;

[0139] Drying is carried out while gathering; the fineness of the gathered sliver is 4829 tex;

[0140] Drawing frame uses a drawing frame machine, draft ratio is 2, and drawing frame speed is 150 m / min;

[0141] During twisting, the set twist is 40 T / m, winding tension is 15 cN, and the fineness of the yarn formed by twisting is 453.2 tex;

[0142] Wrapping means continuously wrapping fibers around the yarn formed by twisting. The wrapping speed is 200 m / min, wrapping angle is 35°, wrapping tension is 5 cN, and wrapping twist is 600 T / m;

[0143] The physical object of the continuous yarn for winding forming is as Figure 1 shown;

[0144] (3)Prepare unidirectional fiber winding reinforced composite material;

[0145] After impregnating the continuous yarn for winding forming with the resin matrix, wind it (the relevant process parameters are set according to the GB / T 1458 - 2023 standard) onto the core mold, then carry out heating and curing forming, and finally cool and demold to obtain the unidirectional fiber winding reinforced composite material.

[0146] The final obtained unidirectional fiber winding reinforced composite material has a fiber mass content of 50.78%, a fiber volume content of 32.09%, a fiber tensile strength of 832.69 MPa, a fiber tensile modulus of 53.29 GPa, and a density of 1.52 g / cm 3 , with a tensile strength of 267.21 MPa and a tensile modulus of 17.10 GPa.

[0147] Example 5

[0148] A preparation method of unidirectional fiber winding reinforced composite material, the specific steps are as follows:

[0149] (1)Preparation of raw materials;

[0150] Discontinuous high-performance fibers: glass fibers, manufacturer is Zhejiang Hengshi Industry Co., Ltd., grade is E8 - UD1250, average length is 80 mm;

[0151] Thermoplastic resin fibers: PA56 fibers, manufacturer is Shanghai Kaisai Biotechnology Co., Ltd., grade is T - 1105, average length is 80 mm;

[0152] Sizing agent A: The solute is a sizing agent (manufacturer is Changsha Xindehang Chemical Co., Ltd., grade is MH - 681), the solvent is deionized water, the concentration is 6.0 wt%, and the viscosity is 37 mPa·s;

[0153] Continuous fibers: small tow continuous fibers with a fineness of 20 D;

[0154] Epoxy resin A: The manufacturer is Swancor New Materials Technology Co., Ltd., and the grade is SWANCOR 2554-K;

[0155] Resin matrix: Epoxy resin B, the manufacturer is Swancor New Materials Technology Co., Ltd., and the grade is EzCicloRB241;

[0156] (2) Prepare continuous yarns for filament winding molding;

[0157] The production process of continuous yarns for filament winding molding is: mixing and opening → carding → sizing → gathering → drawing → twisting → wrapping;

[0158] Mixing and opening means using an opener to mix and open non - continuous high - performance fibers and thermoplastic resin fibers. The mass ratio of non - continuous high - performance fibers to thermoplastic resin fibers is 9:1, the feeding speed is 2 m / min, and the speed of the opening beater is 1500 rpm;

[0159] Carding is carried out using a carding machine. The speed of the cylinder is 400 rpm, the speed of the doffer is 200 rpm, and the feeding speed is 1.5 m / min;

[0160] For the sizing process, sizing solution A is used, and the spraying method is adopted. The sizing rate of the sizing process is the set sizing rate, and the set sizing rate is 2.8%;

[0161] Drying is carried out while gathering; the fineness of the yarn strip obtained by gathering is 4873 tex; the thickness of the molded plate obtained by molding the yarn strip obtained by gathering and epoxy resin A by compression molding is 2.6 mm, the fiber mass content is 69.55%, the fiber volume content is 51.13%, and the density is 1.916 g / cm 3 , the 0° tensile strength is 236 MPa, the 0° tensile modulus is 30.8 GPa, the 0° compressive strength is 451 MPa, the 0° compressive modulus is 31.4 GPa, the 0° flexural strength is 415 MPa, and the 0° flexural modulus is 35.6 GPa; The specific process of compression molding is: lay the yarn strips obtained by gathering side by side in the same direction in layers, place epoxy resin A between the layers, then put them into a mold, and then put the mold into a flat vulcanizing machine. After preheating at 80 °C for 30 min under a pressure of 40 T, pressurize to 150 T and carry out heating and curing molding, and then cool and demold to obtain the molded plate;

[0162] Drawing is carried out using a drawing frame, the draft ratio is 2, and the drawing speed is 150 m / min;

[0163] When twisting, the set twist is 40 T / m, the winding tension is 15 cN, and the fineness of the yarn formed by twisting is 453.2 tex;

[0164] Wrap the continuous fibers around the yarn formed by twisting. The wrapping speed is 200 m / min, the wrapping angle is 35°, the wrapping tension is 5 cN, and the wrapping twist is 600 T / m;

[0165] (3)Prepare unidirectional fiber wound reinforced composites;

[0166] After impregnating the continuous yarn for winding molding with the resin matrix, wind it (the relevant process parameters are set according to the GB / T 1458-2023 standard) onto the core mold, then carry out temperature rise and curing molding, and finally cool and demold to obtain unidirectional fiber wound reinforced composites.

[0167] The fiber mass content of the finally obtained unidirectional fiber wound reinforced composite is 41.12%, the fiber volume content is 24.23%, the fiber tensile strength is 1123.40 MPa, the fiber tensile modulus is 61.08 GPa, and the density is 1.462 g / cm 3 , the tensile strength is 272.20 MPa, and the tensile modulus is 14.80 GPa.

[0168] Comparative Example 1

[0169] Basically the same as Example 5, the difference is only that: the sizing process is not carried out; the thickness of the molded plate obtained by molding the gathered yarn and epoxy resin A is 2.9 mm, the fiber mass content is 70.62%, the fiber volume content is 52.40%, and the density is 1.828 g / cm 3 , the 0° tensile strength is 205 MPa, the 0° tensile modulus is 28.1 GPa, the 0° compressive strength is 395 MPa, the 0° compressive modulus is 28.2 GPa, the 0° bending strength is 313 MPa, and the 0° bending modulus is 24.7 GPa.

[0170] Compared with Comparative Example 1, when the fiber volume content in the composite material is close, the mechanical properties of the molded plate obtained by molding the gathered yarn and epoxy resin A are significantly better than those of Comparative Example 1. Among them, the 0° tensile strength is increased by 15.12%, the 0° tensile modulus is increased by 9.61%, the 0° compressive strength is increased by 14.18%, the 0° compressive modulus is increased by 11.35%, the 0° bending strength is increased by 32.59%, and the 0° bending modulus is increased by 44.13%. It can be seen that the uniform surface modification of the inside and outside of the yarn net can be completed by using the spray method for sizing between the carding process and the gathering process.

Claims

1. A production process for continuous yarn used in winding molding, including a mixing and opening process, a carding process, a gathering process, a drawing process, and a twisting process; Mixing and opening means mixing discontinuous high-performance fibers and thermoplastic resin fibers and then opening them. There is no sizing agent on the surface of the discontinuous high-performance fibers; It is characterized in that It also includes a sizing process; There is a total of one sizing process, which is located between the carding process and the gathering process and uses the spraying method; the sizing rate is equal to the set sizing rate, and the set sizing rate is not higher than 3%; Drying is carried out while gathering.

2. The production process of a continuous yarn for winding molding according to claim 1, characterized in that, The concentration of the sizing solution used for sizing is 3.5 - 6.5 wt%, and the viscosity is 15 - 45 mPa·s.

3. The production process of a continuous yarn for winding molding according to claim 1, characterized in that, The average length of the discontinuous high-performance fibers is 40 - 200 mm. The discontinuous high-performance fibers are glass fibers, carbon fibers, basalt fibers, or boron fibers; the average length of the thermoplastic resin fibers is the same as that of the discontinuous high-performance fibers. The thermoplastic resin fibers are PA fibers, PET fibers, PP fibers, PEEK fibers, or PPS fibers.

4. The production process of a continuous yarn for winding molding according to claim 1, characterized in that, For mixing and opening, an opener is used, the feeding speed is 0.5 - 2.0 m / min, and the speed of the opening beater is 800 - 1500 rpm; for carding, a carding machine is used, the speed of the cylinder is 100 - 400 rpm, the speed of the doffer is 50 - 200 rpm, and the feeding speed is 0.3 - 1.5 m / min; for drawing, a drawing frame is used, the draft ratio is 1.5 - 3.0, and the drawing speed is 50 - 150 m / min; when twisting, the set twist is 20 - 40 T / m, and the winding tension is 5 - 15 cN; the fineness of the yarn strip obtained by gathering is 2383 - 4873 tex, and the fineness of the yarn formed by twisting is 426.3 - 488.3 tex.

5. A production process for continuous yarn used in winding molding, including a mixing and opening process, a carding process, a gathering process, a drawing process, and a twisting process; Mixing and opening means mixing discontinuous high-performance fibers and thermoplastic resin fibers and then opening them. There is no sizing agent on the surface of the discontinuous high-performance fibers; It is characterized in that, It also includes a sizing process; There are two sizing processes in total. The first sizing process is located between the carding process and the gathering process and uses the spraying method. The second sizing process is located after the twisting process and uses the dipping method; the sizing agents used in the two sizing processes are the same. The sizing rate of the first sizing is 60 - 75% of the set sizing rate, and the total sizing rate of the two sizing processes is equal to the set sizing rate. The set sizing rate is not higher than 3%; Drying is carried out while gathering.

6. The production process of a continuous yarn for winding molding according to claim 5, characterized in that, The concentration of the sizing solution used for the first sizing is 3.5 - 6.5 wt%, and the viscosity is 15 - 45 mPa·s; the concentration of the sizing solution used for the second sizing is 1.0 - 2.5 wt%, and the viscosity is 2 - 10 mPa·s; when carrying out the second sizing, the dipping temperature is 35 - 60 °C, and the dipping time is 5 - 20 s.

7. The production process of a continuous yarn for winding molding according to claim 5, characterized in that, It also includes a wrapping process located between the twisting process and the second sizing process. Wrapping means wrapping continuous fibers around the yarn formed by twisting.

8. The production process of a continuous yarn for winding molding according to claim 7, characterized in that, The continuous fiber is a small tow continuous fiber with a fineness of 20 - 150 D; during wrapping, the wrapping speed is 50 - 200 m / min, the wrapping angle is 15 - 35°, the wrapping tension is 5 - 20 cN, and the wrapping twist is 200 - 800 T / m.

9. A continuous yarn for winding molding, characterized in that, It is prepared by using the production process of a continuous yarn for winding molding according to any one of claims 7 - 8.

10. The application of a continuous yarn for winding molding according to claim 9, wherein, After impregnating the continuous yarn for winding molding with a resin matrix, it is wound onto a core mold, and then after heating and curing to form, it is cooled and demolded to obtain a unidirectional fiber-wound reinforced composite material.

Images