Three-dimensional woven rectangular composite material continuous rod, preparation mold and preparation method

Abstract

The invention discloses a three-dimensional woven rectangular composite material continuous rod, a preparation mold and a preparation method.The composite material continuous rod is formed by compounding a resin matrix material and a fiber structure, and the fiber structure comprises an inner layer rod body and an outer layer wrapping the inner layer rod body; the inner-layer rod body is a three-dimensional fiber rectangular rod manufactured through a three-dimensional weaving technology, and the outer layer is a two-dimensional fiber weaving layer. The fiber structure of the three-dimensional woven rectangular composite material continuous rod comprises the three-dimensional inner-layer rod body and the two-dimensional woven layer on the outer side, the abrasion resistance of the rod body can be effectively enhanced, and the service life is prolonged; through the improvement of two sections of S-shaped cavity runners and double glue injection holes of the glue injection mold, dynamic glue dipping is realized, the porosity is reduced, the mechanical property of a product is ensured, the problems of layering and cracking are avoided, and the torsional strength and the shear strength are improved.

Description

Technical Field

[0001] The invention belongs to the field of oil production equipment in the petroleum industry, and in particular relates to a three-dimensional braided rectangular composite material continuous rod, a preparation mold and a preparation method. Background Art

[0002] In domestic and foreign sucker rod pumping systems, the sucker rod is one of the key components. Compared with ordinary steel sucker rods, traditional composite sucker rods have the characteristics of light weight (1 / 4 of steel rods), high strength (2-3 times that of steel rods), and corrosion resistance. However, during downhole service, due to the alternating effects of coupled factors such as acid and alkali corrosion, alternating loads, high temperature and high pressure, the aging of the resin and the splitting process of the fiber rod are greatly aggravated. Therefore, studying the long-term durability of fiber-reinforced composite rods under complex coupled factors has become one of the current research focuses in the fields of composite materials and petroleum engineering. For example:

[0003] Chinese patent application publication number CN1461870A discloses a fiber-reinforced composite continuous sucker rod and its preparation method. The rod utilizes a sheathed composite structure consisting of an inner layer of unidirectionally arranged carbon fiber bundles and an outer layer of high-performance fiber fabric, laminated with a vinyl ester matrix resin. The high-performance fiber fabric used for the outer sheath is a blend of aramid, glass, or ultra-high molecular weight polyethylene fibers. The weft of the blend consists of transversely arranged aramid or ultra-high molecular weight polyethylene fiber bundles to improve transverse splitting resistance and abrasion resistance, while the warp consists of longitudinally arranged, spaced-apart aramid or ultra-high molecular weight polyethylene and glass fiber tapes. The cross-sectional geometry of the sucker rod is rectangular or elliptical.

[0004] Chinese patent application with publication number CN1556303A discloses a high-temperature resistant carbon fiber composite continuous pumping rod, which has an oblate, flexible, continuous structure and is composed of carbon fiber reinforcement and glass fiber ribbons on a phenolic resin matrix.

[0005] A Chinese patent application with publication number CN105298403A discloses a continuous carbon fiber sucker rod with a wear-resistant protective layer, comprising a sucker rod body, a glass fiber layer coated on the surface of the sucker rod body, and a wear-resistant layer coated on the outside of the glass fiber layer. The wear-resistant layer comprises a fiber-reinforced fabric and a thermoplastic resin layer coated on the surface of the fiber-reinforced fabric. Hard wear-resistant particles are evenly mixed in the thermoplastic resin layer, so that the hard wear-resistant particles are evenly distributed on the surface of the wear-resistant layer.

[0006] Chinese patent application publication number CN106194046A discloses a multi-layer, wear-resistant carbon fiber continuous sucker rod, comprising a carbon fiber core, on the outside of which a wound glass fiber layer A and a wound glass fiber layer B are spirally wound, the wound glass fiber layer B is coated with a longitudinal glass fiber layer, the outer wall of the longitudinal glass fiber layer is coated with an epoxy resin layer, and the outer side of the epoxy resin layer is also coated with a polyethylene layer.

[0007] As can be seen from the above technical solutions, existing carbon fiber continuous sucker rod manufacturing technologies all utilize concentric, elliptical, or oblate structures of carbon fiber and glass fiber. These structures all exhibit weak interfacial layers, which can easily cause interlayer separation during use and result in poor torsional resistance. Although patent publication number CN1461870A discloses a rectangular cross-section sucker rod, it also consists of a multi-layered composite structure, similarly subject to the problem of easy interlayer delamination and poor torsional resistance.

[0008] Therefore, in order to address the shortcomings of traditional composite material sucker rods, the present invention introduces the concept of three-dimensional structure, conducts research and development and optimization of the three-dimensional structure composite material sucker rod structure, and develops a new three-dimensional structure composite material sucker rod, which can effectively improve the overall performance of the composite material rod body.

[0009] In view of this, the present invention is proposed. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a three-dimensional braided rectangular composite material continuous rod, a manufacturing mold, and a manufacturing method. The fiber structure of the present invention's three-dimensional braided rectangular composite material continuous rod includes a three-dimensional inner rod body and an outer two-dimensional braided layer, which can effectively enhance the wear resistance of the rod body and increase its service life. At the same time, through the improvement of the two-section "S" cavity flow channel and dual injection holes of the injection mold, dynamic glue impregnation is achieved, the porosity is reduced, the mechanical properties of the product are guaranteed, the problem of delamination and cracking is avoided, and the torsional strength and shear strength are improved.

[0011] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0012] The first purpose of the present invention is to provide a three-dimensional woven rectangular composite material continuous rod, which is formed by a composite of a resin matrix material and a fiber structure, wherein the fiber structure includes an inner layer rod body and an outer layer covering the inner layer rod body, the inner layer rod body is a three-dimensional fiber rectangular rod made by a three-dimensional weaving process, and the outer layer is a two-dimensional fiber woven layer.

[0013] The composite material continuous rod of the present invention has a fiber structure including a three-dimensional inner rod body and an outer two-dimensional woven layer, which can effectively enhance the wear resistance of the rod body and improve its service life; at the same time, the cross-sectional shape is rectangular, which can reduce the coiling diameter and improve the transportation efficiency of the composite material continuous rod.

[0014] In a further embodiment, the three-dimensional braiding angle of the inner rod body is 10-45°, preferably 15-25°.

[0015] The inner rod body can be made using a matrix three-dimensional weaving process, for example, by weaving a three-dimensional fiber rectangular rod with a three-dimensional four-directional, three-dimensional five-directional, or three-dimensional six-directional structure through a two-step method or a four-step method or a rotary three-dimensional weaving process, and then rolling it up.

[0016] When the three-dimensional braiding angle of the inner rod body is controlled within the range of 10-45 degrees in this solution, the fabric tightness is appropriate, which is conducive to the infiltration of the resin glue and can reduce the porosity of the final composite material continuous rod product.

[0017] Preferably, the fiber material of the inner rod body is selected from at least one of carbon fiber, glass fiber, and basalt fiber.

[0018] In a further embodiment, the braiding angle of the two-dimensional fiber braided layer is 45°.

[0019] The two-dimensional fiber braided layer can be made using existing two-dimensional braiding technology, for example, using a 48-spindle two-dimensional braiding machine to coat the inner rod with the two-dimensional fiber braided layer, with the braiding angle of the braided layer controlled to be 45°. The two-dimensional aramid braided layer can improve the surface abrasion resistance.

[0020] Preferably, the fibers of the two-dimensional fiber braided layer are selected from aramid fibers;

[0021] Preferably, the aramid fiber is wear-resistant high modulus aramid 1414 fiber.

[0022] In a further solution, in the three-dimensional woven rectangular composite material continuous rod, the total volume of the inner layer rod body and the outer layer fibers accounts for 45%-80% of the volume of the entire finished product, preferably 65%.

[0023] Fiber volume content is a major factor in determining the performance of fiber-reinforced composites. Theoretically, when the fiber and matrix resin bond well and are similar, the mechanical properties of the composite material increase with increasing fiber volume content, and an optimal value will also exist. Controlling fiber volume content is primarily to adjust the performance parameters of the composite material. During use, composite products will be designed based on the intended use to achieve the desired performance. In this solution, the volume fraction of the inner rod refers to the ratio of the total volume of the fibers used to weave the inner rod to the volume of the entire finished product.

[0024] In a further embodiment, the three-dimensional woven rectangular composite material continuous rod has a tensile strength of 680 MPa-1500 MPa, a bending strength of 600 MPa-1225 MPa, an interlaminar shear strength of 70-135 MPa, and a porosity of 0.8%-5.0%.

[0025] The second object of the present invention is to provide a glue injection mold for preparing continuous rods of composite materials. The glue injection mold includes a main body, and the main body is provided with a cavity with two ends through which fibers pass; the cavity includes a first S-shaped cavity and a second S-shaped cavity arranged in sequence along the direction of fiber advancement.

[0026] Conventional injection molds have linear cavities, allowing fabric to pass through smoothly and quickly, but resulting in poor resin infiltration. The present invention employs an S-shaped cavity. By combining two sections of this cavity with the scalability of the 3D braided inner rod, this allows for dynamic resin infiltration within the mold. This effectively promotes full resin infiltration into the fibers of the 3D braided inner rod, reduces the porosity of the resulting composite continuous rod, and ensures the mechanical properties of the final product.

[0027] It should be noted that the dynamic dipping described in the present invention is relative to the static dipping, which means that the fiber fabric is dipping while moving forward.

[0028] Preferably, the cross-sectional length of the first S-shaped cavity is (1.01-1.20)*a and the width is (0.8-0.99)*b, and the cross-sectional length of the second S-shaped cavity is a and the width is b;

[0029] Wherein, a is the cross-sectional length of the final composite continuous rod product, and b is the cross-sectional width of the final composite three-dimensional braided rod product;

[0030] Preferably, the cross-sectional length of the first S-shaped cavity is (1.05-1.12)*a, (0.88-0.95)*a, and the width is (0.88-0.95)*a.

[0031] The length and width of the cross section of the first and second S-shaped cavities are designed according to the cross section length and width of the required composite material continuous rod, which is beneficial to the deformation and impregnation of the three-dimensional braided fabric and can ensure the enhanced impregnation of the fibers.

[0032] In a further embodiment, the chord length of the arc of the first S-shaped cavity and the second S-shaped cavity is 6-20 cm, and the corresponding chord height is 0.5-6 cm;

[0033] Preferably, the chord length is 8-16 cm, and the chord height is 1.5-4 cm.

[0034] In this solution, if the chord length of the "S" cavity is too long or too small, or the chord height is too large or too small, it is not conducive to the deformation and dipping of the three-dimensional braided fabric.

[0035] In a further solution, the main body is further provided with a first glue injection hole and a second glue injection hole connected to the cavity. Along the direction of fiber advancement, the first glue injection hole is arranged upstream of the first S-shaped cavity, and the second glue injection hole is arranged between the two S-shaped cavities.

[0036] The glue injection mold of the present invention is designed with two front and rear glue injection holes, which are respectively located upstream of the two S-shaped cavities. Injecting glue through the two glue injection holes can improve the fiber wetting effect and reduce glue overflow.

[0037] In a further embodiment, a straight segment cavity can be provided along the fiber fabric's forward direction at the front end of the first S-shaped cavity, / or between the first S-shaped cavity and the second S-shaped cavity, and / or at the rear end of the second S-shaped cavity. The first glue injection hole communicates with the straight segment cavity at the front end of the first S-shaped cavity, and the second glue injection hole communicates with the straight segment cavity between the two S-shaped cavities.

[0038] A third object of the present invention is to provide a method for preparing a continuous rod of a three-dimensional braided rectangular composite material, comprising:

[0039] Step (1), preparing an inner rod body by three-dimensional weaving;

[0040] Step (2), coating the surface of the three-dimensional fiber rectangular rod with a two-dimensional fiber braided layer by two-dimensional braiding;

[0041] Step (3), the product obtained in (2) is sequentially introduced into the injection mold, the cooling device, the pultrusion heating mold, the post-curing furnace, and the crawler traction device, and finally the cured molded product is collected by the winding device.

[0042] In step (1), a determinant three-dimensional braiding process is used to braid a rectangular cross-section inner rod having a three-dimensional four-directional, three-dimensional five-directional, or three-dimensional six-directional structure using a two-step or four-step process or a rotary three-dimensional braiding process, and then the rod is wound. The fiber material can be carbon fiber, and the three-dimensional braiding angle is 10-45°, preferably 15-25°.

[0043] In step (2), the inner rod of the three-dimensional braided rectangular cross-section is unwound and coated with a two-dimensional fiber braid layer on its surface by a 48-spindle two-dimensional braiding machine. The fiber can be aramid fiber, for example, the aramid fiber is wear-resistant high modulus aramid 1414 fiber, and the braiding angle of the two-dimensional braiding machine is 45°.

[0044] In step (3), the three-dimensional woven rectangular inner rod body with the surface covered with aramid two-dimensional braided fabric is sequentially introduced into the injection mold, cooling device, pultrusion heating mold, post-curing furnace, crawler traction device, and finally the cured molded product is collected by the winding device.

[0045] The injection mold is the one described above, having two S-shaped cavities and two injection holes, and the injection pressure is 0.1-1.5 MPa, preferably 0.4-0.75 MPa. Too low an injection pressure will result in insufficient infiltration, while too high an injection pressure will cause the glue to overflow, resulting in waste.

[0046] In a further embodiment, in step (3), the pulling speed is 1-15 cm / min, preferably 5-9 cm / min. A pulling speed that is too fast will affect the infiltration effect of the three-dimensional braided fabric, while a too slow pulling speed will cause the resin to solidify prematurely, making it difficult to pull and extrude.

[0047] In a further embodiment, in step (3), the holding temperature in the cooling device is 30°C;

[0048] The pultrusion heating die is divided into three heating zones, with heating temperatures of 80°C, 110°C, and 140°C respectively;

[0049] The post-curing furnace is divided into three heating zones, with heating temperatures of 150°C, 170°C, and 190°C respectively.

[0050] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0051] The three-dimensional braided rectangular composite continuous rod designed in this invention completely overcomes the shortcomings of conventional composite continuous rods, such as their tendency to delaminate and crack, and their poor torsional and shear strengths. Furthermore, by combining this with conventional pultrusion technology, the curing and molding efficiency of the three-dimensional braided reinforcement is improved.

[0052] 2. Through the design of two "S"-shaped cavity flow channels and double injection holes in the injection mold, combined with the scalability of the three-dimensional braided inner layer rod and the outer layer, dynamic impregnation of the three-dimensional braided inner layer rod in the injection mold is achieved, which effectively promotes the full infiltration of the resin into the fibers of the three-dimensional braided rod, reduces the void ratio of the final rectangular composite material continuous rod, and can ensure the mechanical properties of the final product.

[0053] 3. The continuous rod structure of the present invention, with an inner three-dimensional braided rod and an outer two-dimensional braided layer, effectively enhances the rod's wear resistance and extends its service life. The rectangular cross-section design also reduces the coil diameter, improving the transport efficiency of the rod.

[0054] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0056] Figure 1 It is a schematic diagram of the glue injection mold of the present invention;

[0057] Among them, 1 is the first glue injection hole, 2 is the second glue injection hole, 3 is the first S-shaped cavity, and 4 is the second S-shaped cavity.

[0058] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0060] The present invention provides a glue injection mold for preparing a continuous rod of composite material, comprising a main body, wherein a cavity with two ends through is provided in the main body for fibers to pass through; the cavity comprises a first S-shaped cavity and a second S-shaped cavity sequentially arranged along the advancing direction of the fibers.

[0061] Conventional injection molds have linear cavities, allowing fabric to pass through smoothly and quickly, but resulting in poor resin infiltration. The present invention employs an S-shaped cavity. By combining two sections of this cavity with the scalability of the 3D braided inner rod, this allows for dynamic resin infiltration within the mold. This effectively promotes full resin infiltration into the fibers of the 3D braided inner rod, reduces the porosity of the resulting composite continuous rod, and ensures the mechanical properties of the final product.

[0062] The cross-section of the first S-shaped cavity has a length of (1.01-1.20)*a and a width of (0.8-0.99)*b, and the cross-section of the second S-shaped cavity has a length of a and a width of b;

[0063] Wherein, a is the cross-sectional length of the final composite continuous rod product, and b is the cross-sectional width of the final composite three-dimensional braided rod product;

[0064] Preferably, the cross-sectional length of the first S-shaped cavity is (1.05-1.12)*a, (0.88-0.95)*a, and the width is (0.88-0.95)*a.

[0065] The length and width of the cross section of the first and second S-shaped cavities are designed according to the cross section length and width of the required composite material continuous rod, which is beneficial to the deformation and impregnation of the three-dimensional braided fabric and can ensure the enhanced impregnation of the fibers.

[0066] In a further embodiment, the chord length of the arc of the first S-shaped cavity and the second S-shaped cavity is 6-20 cm, and the corresponding chord height is 0.5-6 cm;

[0067] Preferably, the chord length is 8-16 cm, and the chord height is 1.5-4 cm.

[0068] In this solution, if the chord length of the "S" cavity is too long or too small, or the chord height is too large or too small, it is not conducive to the deformation and dipping of the three-dimensional braided fabric.

[0069] In a further solution, the main body is further provided with a first glue injection hole and a second glue injection hole connected to the cavity. Along the direction of fiber advancement, the first glue injection hole is arranged upstream of the first S-shaped cavity, and the second glue injection hole is arranged between the two S-shaped cavities.

[0070] The glue injection mold of the present invention is designed with two front and rear glue injection holes, which are respectively located upstream of the two S-shaped cavities. Injecting glue through the two glue injection holes can improve the fiber wetting effect and reduce glue overflow.

[0071] In a further embodiment, a straight segment cavity can be provided along the fiber fabric's forward direction at the front end of the first S-shaped cavity, / or between the first S-shaped cavity and the second S-shaped cavity, and / or at the rear end of the second S-shaped cavity. The first glue injection hole communicates with the straight segment cavity at the front end of the first S-shaped cavity, and the second glue injection hole communicates with the straight segment cavity between the two S-shaped cavities.

[0072] The following embodiments all use the above-mentioned "S" cavity injection mold.

[0073] Example 1:

[0074] A determinant three-dimensional braiding square machine is used to weave a continuous three-dimensional inner layer rod with a rectangular cross-section and a three-dimensional five-directional structure, and then reel it up. Specifically, it is woven from four layers of braided yarn and two layers of axial yarn through a four-step method, with a braiding angle of 17°. There are 44 bundles of yarn per layer of braided yarn and 22 bundles of axial yarn per layer, for a total of 220 bundles of yarn. The yarn is made of 12K, T700 carbon fiber. The three-dimensional braided rectangular cross-section inner layer rod is unwound, and a layer of two-dimensional aramid fiber braiding layer is coated on its surface by a 48-spindle two-dimensional braiding machine. The yarn is 1000tex wear-resistant high modulus aramid 1414 fiber, and the braiding angle of the two-dimensional braiding machine is 45°.

[0075] In the finished product of the three-dimensional woven rectangular composite continuous rod, the total fiber volume of the inner rod body and the woven layer accounts for 65%.

[0076] Subsequently, the three-dimensional woven rectangular cross-section inner rod with the surface covered with aramid two-dimensional braided fabric is introduced into the injection mold, mold cooling device, pultrusion heating mold, post-curing furnace, crawler traction device in sequence, and finally the cured molded product is collected by the winding device.

[0077] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection hole. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braided layer, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S"-shaped cavity has a cross-sectional length of 35.2mm and a width of 3.6mm; the rear "S"-shaped cavity has a cross-sectional length of 32mm and a width of 4. The chord length of the arc corresponding to the front and rear "S" cavities is 10cm, and the corresponding chord height is 3cm.

[0078] The two-component glue injection machine uses an injection pressure of 0.6 MPa; the pulling speed is 6 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0079] Example 2:

[0080] A continuous three-dimensional inner rod with a rectangular cross-section and a three-dimensional, four-directional structure is braided and wound using a matrix-type three-dimensional square braiding machine. Specifically, the rod is woven from four layers of braided yarn using a four-step method, with a braiding angle of 17°. A total of 220 bundles of yarn are made of 12K T700 carbon fiber.

[0081] The inner rod of the 3D braided rectangular cross-section is unwound and then coated with a 2D aramid fiber layer on its surface using a 48-spindle 2D braiding machine. The aramid fiber is wear-resistant, high-modulus aramid 1414 fiber, and the 2D braiding machine has a braiding angle of 45°.

[0082] In the finished product of the three-dimensional woven rectangular composite continuous rod, the total fiber volume of the inner rod body and the woven layer accounts for 65%.

[0083] Subsequently, the three-dimensional woven rectangular cross-section inner rod with the surface covered with aramid two-dimensional braided fabric is introduced into the injection mold, mold cooling device, pultrusion heating mold, post-curing furnace, crawler traction device in sequence, and finally the cured molded product is collected by the winding device.

[0084] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection hole. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braided layer, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S"-shaped cavity has a cross-sectional length of 35.2mm and a width of 3.6mm; the rear "S"-shaped cavity has a cross-sectional length of 32mm and a width of 4. The chord length of the arc corresponding to the front and rear "S" cavities is 10cm, and the corresponding chord height is 3cm.

[0085] The two-component glue injection machine uses an injection pressure of 0.6 MPa; the pulling speed is 6 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0086] Example 3:

[0087] A determinant three-dimensional braiding square machine is used to weave a continuous three-dimensional inner layer rod with a rectangular cross-section and a three-dimensional five-directional structure, and then reel it up. Specifically, it is woven from four layers of braided yarn and two layers of axial yarn using a four-step method, with a braiding angle of 35°. There are 44 bundles of yarn per layer of braided yarn and 22 bundles of axial yarn per layer, for a total of 220 bundles of yarn. The yarn is made of 12K, T700 carbon fiber. The three-dimensional braided rectangular cross-section inner layer rod is unwound and coated with a two-dimensional aramid fiber braid layer on its surface using a 48-spindle two-dimensional braiding machine. The aramid fiber is wear-resistant high-modulus aramid 1414 fiber, and the braiding angle of the two-dimensional braiding machine is 45°.

[0088] In the finished product of the three-dimensional woven rectangular composite continuous rod, the total fiber volume of the inner rod body and the woven layer accounts for 65%.

[0089] Subsequently, the three-dimensional woven rectangular cross-section inner rod with the surface covered with aramid two-dimensional braided fabric is introduced into the injection mold, mold cooling device, pultrusion heating mold, post-curing furnace, crawler traction device in sequence, and finally the cured molded product is collected by the winding device.

[0090] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection hole. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braided layer, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S"-shaped cavity has a cross-sectional length of 35.2mm and a width of 3.6mm; the rear "S"-shaped cavity has a cross-sectional length of 32mm and a width of 4. The chord length of the arc corresponding to the front and rear "S" cavities is 10cm, and the corresponding chord height is 3cm.

[0091] The two-component glue injection machine uses an injection pressure of 0.6 MPa; the pulling speed is 6 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0092] Example 4:

[0093] A determinant three-dimensional braiding square machine is used to weave a continuous three-dimensional inner layer rod with a rectangular cross-section and a three-dimensional five-directional structure, and then reel it up. Specifically, it is woven from four layers of braided yarn and two layers of axial yarn using a four-step method, with a braiding angle of 17°. There are 44 bundles of yarn per layer of braided yarn and 22 bundles of axial yarn per layer, for a total of 220 bundles of yarn. The yarn is made of 12K, T700 carbon fiber. The three-dimensional braided rectangular cross-section inner layer rod is unwound and coated with a two-dimensional aramid fiber braid layer on its surface through a 48-spindle two-dimensional braiding machine. The aramid fiber is wear-resistant high modulus aramid 1414 fiber, and the braiding angle of the two-dimensional braiding machine is 45°.

[0094] In the finished product of the three-dimensional woven rectangular composite continuous rod, the total fiber volume of the inner rod body and the woven layer accounts for 65%.

[0095] Subsequently, the three-dimensional woven rectangular cross-section inner rod with the surface covered with aramid two-dimensional braided fabric is introduced into the injection mold, mold cooling device, pultrusion heating mold, post-curing furnace, crawler traction device in sequence, and finally the cured molded product is collected by the winding device.

[0096] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection holes. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braid, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S" cavity has a cross-sectional length of 36.8mm and a width of 3.4mm; the rear "S" cavity has a cross-sectional length of 32mm and a width of 4. The chord length of the arc of the front and rear "S" cavities is 10cm, and the corresponding chord height is 3cm.

[0097] The two-component glue injection machine uses an injection pressure of 0.6 MPa; the pulling speed is 6 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0098] Example 5:

[0099] A determinant three-dimensional braiding square machine is used to weave a continuous three-dimensional inner layer rod with a rectangular cross-section and a three-dimensional five-directional structure, and then reel it up. Specifically, it is woven from four layers of braided yarn and two layers of axial yarn using a four-step method, with a braiding angle of 17°. There are 44 bundles of yarn per layer of braided yarn and 22 bundles of axial yarn per layer, for a total of 220 bundles of yarn. The yarn is made of 12K, T700 carbon fiber. The three-dimensional braided rectangular cross-section inner layer rod is unwound and coated with a two-dimensional aramid fiber braid layer on its surface through a 48-spindle two-dimensional braiding machine. The aramid fiber is wear-resistant high modulus aramid 1414 fiber, and the braiding angle of the two-dimensional braiding machine is 45°.

[0100] In the finished product of the three-dimensional woven rectangular composite continuous rod, the total fiber volume of the inner rod body and the woven layer accounts for 65%.

[0101] Subsequently, the three-dimensional woven rectangular cross-section inner rod with the surface covered with aramid two-dimensional braided fabric is introduced into the injection mold, mold cooling device, pultrusion heating mold, post-curing furnace, crawler traction device in sequence, and finally the cured molded product is collected by the winding device.

[0102] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection holes. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braided layer, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S"-shaped cavity has a cross-sectional length of 35.2mm and a width of 4.4mm; the rear "S"-shaped cavity has a cross-sectional length of 32mm and a width of 4. The chord length of the arc of the front and rear "S" cavities is 6cm, and the corresponding chord height is 5cm.

[0103] The two-component glue injection machine uses an injection pressure of 0.6 MPa; the pulling speed is 6 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0104] Example 6:

[0105] A determinant three-dimensional braiding square machine is used to weave a continuous three-dimensional inner layer rod with a rectangular cross-section and a three-dimensional five-directional structure, and then reel it up. Specifically, it is woven from four layers of braided yarn and two layers of axial yarn using a four-step method, with a braiding angle of 17°. There are 44 bundles of yarn per layer of braided yarn and 22 bundles of axial yarn per layer, for a total of 220 bundles of yarn. The yarn is made of 12K, T700 carbon fiber. The three-dimensional braided rectangular cross-section inner layer rod is unwound and coated with a two-dimensional aramid fiber braid layer on its surface through a 48-spindle two-dimensional braiding machine. The aramid fiber is wear-resistant high modulus aramid 1414 fiber, and the braiding angle of the two-dimensional braiding machine is 45°.

[0106] In the finished product of the three-dimensional woven rectangular composite continuous rod, the total fiber volume of the inner rod body and the woven layer accounts for 65%.

[0107] Subsequently, the three-dimensional woven rectangular cross-section inner rod with the surface covered with aramid two-dimensional braided fabric is introduced into the injection mold, mold cooling device, pultrusion heating mold, post-curing furnace, crawler traction device in sequence, and finally the cured molded product is collected by the winding device.

[0108] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection hole. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braided layer, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S"-shaped cavity has a cross-sectional length of 35.2mm and a width of 3.6mm; the rear "S"-shaped cavity has a cross-sectional length of 32mm and a width of 4. The corresponding chord length of the arc of the front and rear "S" cavities is 18cm, and the corresponding chord height is 1cm.

[0109] The two-component glue injection machine uses an injection pressure of 0.6 MPa; the pulling speed is 6 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0110] Example 7:

[0111] A continuous three-dimensional inner-layer rod with a rectangular cross-section and a five-directional structure is braided and wound using a determinant three-dimensional square braiding machine. Specifically, it is woven using a four-step process with four layers of braided yarn and two layers of axial yarn, with a braiding angle of 17°. Each braided yarn layer contains 44 strands, and each axial yarn layer contains 22 strands, for a total of 220 strands. The yarn is made of 12K T700 carbon fiber.

[0112] The inner rod of the 3D braided rectangular cross-section is unwound and then coated with a 2D aramid fiber layer on its surface using a 48-spindle 2D braiding machine. The aramid fiber is wear-resistant, high-modulus aramid 1414 fiber, and the 2D braiding machine has a braiding angle of 45°.

[0113] In the finished product of the three-dimensional woven rectangular composite continuous rod, the total fiber volume of the inner rod body and the woven layer accounts for 65%.

[0114] Subsequently, the three-dimensional woven rectangular cross-section inner rod with the surface covered with aramid two-dimensional braided fabric is introduced into the injection mold, mold cooling device, pultrusion heating mold, post-curing furnace, crawler traction device in sequence, and finally the cured molded product is collected by the winding device.

[0115] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection hole. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braided layer, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S"-shaped cavity has a cross-sectional length of 35.2mm and a width of 3.6mm; the rear "S"-shaped cavity has a cross-sectional length of 32mm and a width of 4. The chord length of the arc corresponding to the front and rear "S" cavities is 10cm, and the corresponding chord height is 3cm.

[0116] The two-component glue injection machine uses an injection pressure of 0.2 MPa; the pulling speed is 6 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0117] Example 8:

[0118] A determinant three-dimensional braiding square machine is used to weave a continuous three-dimensional inner layer rod with a rectangular cross-section and a three-dimensional five-directional structure, and then reel it up. Specifically, it is woven from four layers of braided yarn and two layers of axial yarn using a four-step method, with a braiding angle of 17°. There are 44 bundles of yarn per layer of braided yarn and 22 bundles of axial yarn per layer, for a total of 220 bundles of yarn. The yarn is made of 12K, T700 carbon fiber. The three-dimensional braided rectangular cross-section inner layer rod is unwound and coated with a two-dimensional aramid fiber braid layer on its surface through a 48-spindle two-dimensional braiding machine. The aramid fiber is wear-resistant high modulus aramid 1414 fiber, and the braiding angle of the two-dimensional braiding machine is 45°.

[0119] In the finished 3D braided rectangular composite continuous rod, the combined fiber volume of the inner rod and braided layer accounts for 65%. The 3D braided rectangular cross-section inner rod, coated with aramid 2D braid, is then sequentially introduced into a glue injection mold, mold cooling unit, pultrusion heating mold, post-curing oven, and crawler traction unit. Finally, the cured product is collected by a winding unit.

[0120] A two-component injection molding machine is used to thoroughly mix epoxy resin, curing agent, and release agent in a mass ratio of 100:100:1 and simultaneously inject them into the injection mold through the injection hole. A three-dimensional braided rectangular inner rod, coated with a two-dimensional braided layer, passes through two "S"-shaped cavities within the injection mold for fiber reinforcement and impregnation. The front "S"-shaped cavity has a cross-sectional length of 35.2mm and a width of 3.6mm; the rear "S"-shaped cavity has a cross-sectional length of 32mm and a width of 4. The chord length of the arc corresponding to the front and rear "S" cavities is 10cm, and the corresponding chord height is 3cm.

[0121] The two-component glue injection machine uses an injection pressure of 0.6 MPa; the pulling speed is 12 cm / min; the cold mold is kept at 30°C; the mold is heated in three zones: 80°C, 110°C, and 140°C; and the post-curing oven has three zones: 150°C, 170°C, and 190°C. Finally, the composite rod is rolled onto a 2m diameter disc.

[0122] Comparative Example 1:

[0123] The other implementation schemes of this comparative example are the same as those of Example 1, except that the inner cavity of the injection mold is linear, 32 mm in length and 4 mm in width.

[0124] Comparative Example 2:

[0125] The other implementation schemes of this comparative example are the same as those of Example 1, except that the glue is only injected from the front glue injection hole (the first glue injection hole).

[0126] The three-dimensional braided rectangular composite material continuous rod products prepared in Examples 1-8 and Comparative Examples 1-2 were subjected to performance testing, and the test results are shown in Table 1 below.

[0127] The detection methods used are as follows:

[0128] Tensile strength / MPa: refer to GB / T 3354;

[0129] Bending strength / MPa: refer to GB / T 3356;

[0130] Interlaminar shear strength / MPa: refer to JC / T 773-2010;

[0131] Void rate %: JC / T 287-2010.

[0132] Table 1 Performance parameters of three-dimensional braided rectangular composite continuous rod

[0133]

[0134] Result analysis:

[0135] As can be seen from Table 1, compared with Comparative Example 1, the composite continuous rods prepared in Examples 1-8 have significantly reduced porosity and significantly improved tensile strength, flexural strength, and shear strength. Among them, the composite continuous rod of Example 1 has the best performance.

[0136] In Comparative Example 2, when glue is injected only through the first glue injection hole, the fibers in this section after being impregnated with glue will be more likely to produce bubbles after being squeezed and deformed by the S-shaped cavity. At the same time, single-hole glue injection is not conducive to the establishment and stabilization of the glue injection pressure, resulting in a high void ratio in the composite material, which ultimately leads to a decrease in the mechanical properties of the composite material. In addition, research has found that when the three-dimensional braiding angle increases, the fabric is woven more tightly, which leads to unfavorable glue infiltration and a high void ratio. When the braiding angle decreases, the fabric tightness decreases, which is more conducive to glue infiltration. The appropriate "S"-shaped cavity cross-sectional size is conducive to the infiltration of three-dimensional braided fabrics with glue. Too large compression will result in poor glue impregnation, while too small compression will be too tight and will not be conducive to glue infiltration. Furthermore, an "S" cavity with an excessively long chord length and a low chord height, or a chord length and a high chord height, is detrimental to the deformation and impregnation of the 3D braid. Low injection pressure leads to insufficient infiltration, while high pressure causes glue overflow and waste. Finally, too fast a pulling speed can also affect the infiltration of the 3D braid, while too slow can prematurely solidify the resin, making it difficult to pultrude. The present invention achieves significant improvements in product performance by controlling the appropriate 3D braiding angle, the appropriate "S" cavity cross-sectional dimensions, the chord length and height, the appropriate injection pressure, and the appropriate pulling speed.

[0137] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present invention can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A three-dimensional braided rectangular composite material continuous rod, characterized in that: It is formed by a composite of a resin matrix material and a fiber structure, wherein the fiber structure includes an inner rod body and an outer layer covering the inner rod body. The inner rod body is a three-dimensional fiber rectangular rod made by a three-dimensional weaving process, and the outer layer is a two-dimensional fiber braided layer.

2. The three-dimensional braided rectangular composite material continuous rod according to claim 1, characterized in that: The three-dimensional braiding angle of the inner rod is 10-45°, preferably 15-25°; Preferably, the fiber material of the inner rod body is selected from at least one of carbon fiber, glass fiber, and basalt fiber.

3. The three-dimensional braided rectangular composite material continuous rod according to claim 1 or 2, characterized in that: The braiding angle of the two-dimensional fiber braided layer is 45°; Preferably, the fibers of the two-dimensional fiber braided layer are selected from aramid fibers; Preferably, the aramid fiber is wear-resistant high modulus aramid 1414 fiber.

4. The three-dimensional braided rectangular composite material continuous rod according to any one of claims 1 to 3, characterized in that: In the three-dimensional braided rectangular composite material continuous rod, the total volume of the inner layer rod body and the outer layer fiber accounts for 45%-80% of the volume of the entire finished product; preferably, the proportion is 65%.

5. A glue injection mold for preparing a continuous composite material rod, characterized in that: The injection mold includes a body, wherein the body is provided with a cavity with two ends through which the fiber passes, the cavity including a first S-shaped cavity and a second S-shaped cavity sequentially arranged along the advancing direction of the fiber; Preferably, the cross-sectional length of the first S-shaped cavity is (1.01-1.20)*a and the width is (0.8-0.99)*b, and the cross-sectional length of the second S-shaped cavity is a and the width is b; Wherein, a is the cross-sectional length of the final composite continuous rod product, and b is the cross-sectional width of the final composite three-dimensional braided rod product; Preferably, the cross-sectional length of the first S-shaped cavity is (1.05-1.12)*a, (0.88-0.95)*a, and the width is (0.88-0.95)*a.

6. The injection mold according to claim 5, characterized in that: The chord length corresponding to the arc of the first S-shaped cavity and the second S-shaped cavity is 6-20 cm, and the corresponding chord height is 0.5-6 cm; Preferably, the chord length is 8-16 cm, and the chord height is 1.5-4 cm.

7. The injection mold according to claim 5 or 6, characterized in that: The main body is further provided with a first glue injection hole and a second glue injection hole connected to the cavity. Along the advancing direction of the fiber, the first glue injection hole is arranged upstream of the first S-shaped cavity, and the second glue injection hole is arranged between the two S-shaped cavities.

8. A method for preparing a continuous rod of a three-dimensional braided rectangular composite material according to any one of claims 1 to 4, characterized in that: include: (1) The inner rod is prepared by a three-dimensional braiding method; (2) coating the surface of the three-dimensional fiber rectangular rod with a two-dimensional fiber braided layer by two-dimensional braiding; (3) The product obtained in (2) is sequentially introduced into a glue injection mold, a cooling device, a pultrusion heating mold, a post-curing furnace, and a crawler traction device, and finally the cured molded product is collected by a winding device; Preferably, in step (3), the injection mold adopts the injection mold as described in any one of claims 5 to 7, and the injection pressure is 0.1-1.5 MPa, preferably 0.4-0.75 MPa.

9. The preparation method according to claim 8, characterized in that In step (3), the pulling speed is 1-15 cm / min, preferably 5-9 cm / min.

10. The preparation method according to claim 8 or 9, characterized in that: In step (3), In the cooling device, the holding temperature is 30°C; The pultrusion heating die is divided into three heating zones, with heating temperatures of 80°C, 110°C, and 140°C respectively; The post-curing furnace is divided into three heating zones, with heating temperatures of 150°C, 170°C, and 190°C respectively.

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