Carbon fiber buoyancy material filled with circular tube as well as preparation method and application of carbon fiber buoyancy material

Abstract

The invention provides a carbon fiber buoyancy material filled with a circular tube as well as a preparation method and application of the carbon fiber buoyancy material, and belongs to the technical field of composite materials. The buoyancy material provided by the invention comprises a hexagonal close-packed carbon fiber circular tube, an end cap, a filling material and epoxy resin, the outermost ring of the hexagonal close-packed carbon fiber round tube is filled with the filling material, the end caps are packaged at the two ends of the hexagonal close-packed carbon fiber round tube, and gaps of the hexagonal close-packed carbon fiber round tube are filled with the epoxy resin; and the density of the filling material is less than 1g / cm < 3 >. The carbon fiber circular tube on the outermost circle of the buoyancy material is filled with the filling material, the filling material enables the buoyancy material to absorb more energy in the collision process, the collision resistance of the buoyancy material is enhanced, and meanwhile the water pressure resistance of the buoyancy material is improved; the density of the filling material is controlled, the weight of the buoyancy material is reduced, and light weight of the buoyancy material is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a carbon fiber buoyancy material filled with a circular tube, and a preparation method and application thereof. Background Art

[0002] Buoyancy materials are key materials for underwater equipment such as underwater submersibles and detection equipment to complete the buoyancy and diving movements. Their weight and volume account for a large proportion. Reducing the weight of buoyancy materials can greatly increase the payload, endurance and maneuverability of underwater equipment, which is of great significance to improving the comprehensive technical level of underwater equipment.

[0003] In order to improve the performance of buoyancy materials, a carbon fiber porous buoyancy material composed of carbon fiber round tubes and epoxy resin has been invented. However, the structure of this buoyancy material is fixed, and further optimization is difficult. It is difficult to further improve its water pressure resistance while ensuring lightweight. In addition, this structure composed of carbon fiber round tubes is relatively brittle and prone to brittle fracture when subjected to impact loads, which is not conducive to practical application. Therefore, how to further improve the water pressure resistance and impact resistance of the buoyancy material while ensuring lightweight has become a difficult problem in the prior art. Summary of the invention

[0004] The object of the present invention is to provide a carbon fiber buoyancy material filled with a circular tube and a preparation method and application thereof. The buoyancy material provided by the present invention has higher water pressure resistance and excellent impact resistance while ensuring light weight.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a carbon fiber buoyancy material filled with a circular tube, comprising a hexagonal closest-packed carbon fiber circular tube, an end cap, a filling material and an epoxy resin; the filling material is filled in the outermost circle of the hexagonal closest-packed carbon fiber circular tube, the end cap is encapsulated at both ends of the hexagonal closest-packed carbon fiber circular tube, and the epoxy resin is filled in the gap of the hexagonal closest-packed carbon fiber circular tube; the density of the filling material is less than 1g / cm 3 .

[0007] Preferably, the inner diameter of a single carbon fiber round tube in the hexagonal closest packed carbon fiber round tube is 4 to 100 mm.

[0008] Preferably, the wall thickness of a single carbon fiber round tube in the hexagonal closest packed carbon fiber round tube is 0.12-10 mm.

[0009] Preferably, the end cap is made of carbon fiber.

[0010] Preferably, the end cap is in the shape of a disc; the diameter of the end cap is the same as the outer diameter of a single carbon fiber circular tube in the hexagonal close-packed carbon fiber circular tube.

[0011] Preferably, the filling material is rigid foam.

[0012] Preferably, the curing temperature of the epoxy resin is room temperature, the room temperature viscosity of the epoxy resin < 220 MPa·s, the compressive strength > 95 MPa, and the compressive modulus > 3.5 MPa.

[0013] The present invention also provides a method for preparing the carbon fiber buoyancy material filled in the circular tube described in the above technical solution, including the following steps:

[0014] (1) The carbon fiber prepreg is wound into a tube and then cured to obtain a carbon fiber circular tube;

[0015] (2) The partial carbon fiber circular tubes obtained in the step (1) are filled and encapsulated with end caps and filling materials to obtain encapsulated filled carbon fiber circular tubes; the remaining carbon fiber circular tubes obtained in the step (1) are encapsulated with end caps to obtain encapsulated carbon fiber circular tubes;

[0016] (3) The encapsulated filled carbon fiber circular tubes and the encapsulated carbon fiber circular tubes obtained in the step (2) are arranged in a hexagonal close-packed manner, and after pouring epoxy resin and curing, a carbon fiber buoyancy material filled in the circular tube is obtained.

[0017] Preferably, in the step (1), the curing temperature is 120 - 140 °C, and the curing time is 80 - 100 min.

[0018] The present invention also provides the application of the carbon fiber buoyancy material filled in the circular tube described in the above technical solution or the carbon fiber buoyancy material filled in the circular tube prepared by the preparation method described in the above technical solution in underwater equipment.

[0019] The present invention provides a carbon fiber buoyancy material filled in a circular tube, including hexagonal close-packed carbon fiber circular tubes, end caps, filling materials and epoxy resin; the filling materials are filled in the outermost ring of the hexagonal close-packed carbon fiber circular tubes, the end caps are encapsulated at both ends of the hexagonal close-packed carbon fiber circular tubes, and the epoxy resin is filled in the voids of the hexagonal close-packed carbon fiber circular tubes; the density of the filling material < 1 g / cm 3In the present invention, a filling material is filled in the outermost carbon fiber circular tube of the buoyancy material. The filled filling material enables the buoyancy material to absorb more energy during impact, enhancing the impact resistance of the buoyancy material, and at the same time improving the water pressure resistance of the buoyancy material. By controlling the density of the filling material, the weight of the buoyancy material is reduced, ensuring the lightweight of the buoyancy material. The results of the examples show that the average net water pressure strength of the buoyancy material provided by the present invention is above 30 MPa, and the maximum impact load is above 250 kN. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 FIG. is a schematic structural diagram of a single carbon fiber circular tube filled with a filling material in the carbon fiber buoyancy material with circular tube filling provided by the present invention;

[0021] Figure 2 FIG. is a schematic structural diagram of the carbon fiber buoyancy material with circular tube filling provided by the present invention;

[0022] Figure 3 FIG. is a comparison chart of the water pressure resistance performance of the buoyancy materials in Examples 1-2 and Comparative Examples 1-3;

[0023] Figure 4 FIG. is a comparison chart of the impact resistance performance of the buoyancy materials in Examples 1-2 and Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention provides a carbon fiber buoyancy material with circular tube filling, including a carbon fiber circular tube with hexagonal closest packing, end caps, a filling material, and epoxy resin; the filling material is filled in the outermost circle of the carbon fiber circular tube with hexagonal closest packing, the end caps are encapsulated at both ends of the carbon fiber circular tube with hexagonal closest packing, and the epoxy resin is filled in the voids of the carbon fiber circular tube with hexagonal closest packing; the density of the filling material < 1 g / cm 3 .

[0025] The carbon fiber buoyancy material with circular tube filling provided by the present invention includes a carbon fiber circular tube with hexagonal closest packing.

[0026] In the present invention, the inner diameter of a single carbon fiber circular tube in the carbon fiber circular tube with hexagonal closest packing is preferably 4-100 mm. As an implementation manner, the inner diameter of a single carbon fiber circular tube in the carbon fiber circular tube with hexagonal closest packing can specifically be 4 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100 mm.

[0027] In the present invention, the wall thickness of a single carbon fiber circular tube in the hexagonal close-packed carbon fiber circular tubes is preferably 0.12 to 10 mm. As an implementation manner, the wall thickness of a single carbon fiber circular tube in the hexagonal close-packed carbon fiber circular tubes may specifically be 0.12 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0028] The present invention has no special limitation on the length of a single carbon fiber circular tube in the hexagonal close-packed carbon fiber circular tubes, and it can be selected according to actual needs. In the present invention, the length of a single carbon fiber circular tube in the hexagonal close-packed carbon fiber circular tubes may specifically be 100 mm. By controlling the inner diameter and wall thickness of the carbon fiber circular tube within the above ranges, the present invention can further improve the performance of the buoyancy material.

[0029] The carbon fiber buoyancy material filled with circular tubes provided by the present invention further includes end caps.

[0030] In the present invention, the end caps are encapsulated at both ends of the hexagonal close-packed carbon fiber circular tubes.

[0031] In the present invention, the material of the end caps is preferably carbon fiber. By using end caps made of carbon fiber, the weight of the buoyancy material can be further reduced. The present invention has no special limitation on the source of the carbon fiber, and commercially available products well-known to those skilled in the art can be used.

[0032] In the present invention, the shape of the end caps is preferably a circular disc; the thickness of the circular disc is preferably 3 to 3.5 mm, and more preferably 3.2 mm.

[0033] In the present invention, the diameter of the end caps is preferably the same as the outer diameter of a single carbon fiber circular tube in the hexagonal close-packed carbon fiber circular tubes.

[0034] The present invention preferably subjects the carbon fiber prepreg to pressure curing to obtain the end caps.

[0035] In the present invention, the carbon fiber prepreg is preferably purchased from the T700-12K / 50g carbon fiber prepreg produced by Shandong Kehang New Materials Co., Ltd.

[0036] The present invention preferably lays multiple layers of carbon fiber prepreg and then subjects them to pressure curing to obtain the end caps.

[0037] In the present invention, the thickness of each layer of carbon fiber prepreg is preferably 0.04 to 0.06 mm, and more preferably 0.05 mm.

[0038] In the present invention, the laying angles of the carbon fiber prepreg are preferably repeated in the order of 0° / 45° / 90° / -45°. By controlling the laying angles within the above range, the flatness of the laying process can be ensured and the approaching surface of the end cap can be made isotropic.

[0039] The present invention has no special limitation on the specific number of layers of the carbon fiber prepreg, as long as the thickness of the end cap is within the above range.

[0040] In the present invention, the pressure curing is preferably as follows: keep warm at 75 - 85°C for 25 - 35 min, and then keep warm at 120 - 140°C for 80 - 100 min; more preferably, keep warm at 80°C for 30 min and then keep warm at 130°C for 90 min; the pressure for the pressure curing is preferably 0.2 - 0.4 MPa, more preferably 0.3 MPa; the pressure curing is preferably carried out under vacuum conditions. The present invention has no special limitation on the vacuum degree of the vacuum conditions, and the vacuum conditions well-known to those skilled in the art can be adopted. By controlling the conditions of the pressure curing within the above range, sufficient curing can be achieved.

[0041] In the present invention, the pressure curing is preferably carried out in an autoclave. The present invention has no special limitation on the model of the autoclave, and commercially available equipment well-known to those skilled in the art can be adopted.

[0042] After the pressure curing is completed, the present invention preferably cuts the product of the pressure curing to obtain the end cap. The present invention has no special limitation on the cutting operation, as long as the size of the end cap is within the above range.

[0043] The end cap adopted by the present invention can achieve a better sealing effect on the carbon fiber circular tube, and at the same time will not have an adverse impact on the performance of the buoyancy material. The present invention encapsulates end caps at both ends of each carbon fiber circular tube respectively, and the separate encapsulation replaces the traditional integral encapsulation, avoiding serious cumulative deformation and stress concentration at the ends during the loading process of the buoyancy material, and enhancing the stability of the encapsulation.

[0044] The carbon fiber buoyancy material filled in the circular tube provided by the present invention further includes a filling material.

[0045] In the present invention, the filling material is filled in the outermost ring of the carbon fiber circular tubes in hexagonal close-packed arrangement.

[0046] In the present invention, the density of the filling material < 1 g / cm 3 .

[0047] In the present invention, the filling material is preferably a rigid foam material, more preferably a metal foam or a glass microsphere-reinforced epoxy resin composite material. The present invention has no special limitation on the source of the filling material, and commercially available products well-known to those skilled in the art can be adopted.

[0048] In the present invention, the metal foam preferably comprises aluminum foam or copper foam.

[0049] In the present invention, the filling material is preferably cylindrical; the diameter of the filling material is preferably the same as the inner diameter of the carbon fiber circular tube; the length of the filling material is preferably the same as the length of the carbon fiber circular tube.

[0050] When the size of the filling material is not within the above range, the present invention preferably cuts the filling material.

[0051] In the present invention, the cutting method is preferably water jet cutting or wire cutting. By adopting the above cutting method, the present invention can reduce the damage to the pore structure of the filling material. The present invention has no special limitation on the operation of the water jet cutting or wire cutting, and the technical solutions well-known to those skilled in the art can be adopted.

[0052] The present invention fills the filling material in the outermost circle, which can avoid the carbon fiber fracture failure caused by the buckling of the outermost carbon fiber circular tube under the action of water pressure load, improve the water pressure resistance of the buoyancy material with the highest efficiency, and at the same time, the filling material enables the buoyancy material to absorb more energy during the impact process, enhancing the impact resistance of the buoyancy material; by controlling parameters such as the density of the filling material, the weight of the buoyancy material is reduced, ensuring the lightweight of the buoyancy material.

[0053] The carbon fiber buoyancy material filled in the circular tube provided by the present invention further comprises epoxy resin.

[0054] In the present invention, the epoxy resin is filled in the voids of the carbon fiber circular tubes in hexagonal closest packing.

[0055] In the present invention, the curing temperature of the epoxy resin is preferably room temperature; the room temperature viscosity of the epoxy resin is preferably <220 MPa·s, the compressive strength is preferably >95 MPa, and the compressive modulus is preferably >3.5 MPa. By adopting the above epoxy resin, the present invention is more conducive to operation and can further improve the impact resistance of the buoyancy material.

[0056] The present invention has no special limitation on the specific type of the epoxy resin, and commercially available products well-known to those skilled in the art and meeting the above requirements can be adopted. In the present invention, the epoxy resin can be specifically 9350, which is composed of a matrix resin and a curing agent with a mass ratio of 10:3; wherein, the matrix resin is composed of bisphenol A epoxy resin 0164 and diluent XY622 with a mass ratio of 17:3; the two components of the curing agent are D230 and 593 with a mass ratio of 3:1.

[0057] In the present invention, the epoxy resin is used to bond the carbon fiber circular tubes to form the buoyancy material.

[0058] The present invention utilizes the characteristics of the hard filling foam, which is lightweight, high strength and high rigidity, to improve the anti-buckling performance of the outermost carbon fiber round tube of the buoyancy material, thereby improving the water pressure resistance and collision resistance of the buoyancy material while ensuring the lightweight characteristics. Specifically, the hard foam has a high rigidity and can support the carbon fiber round tube, making it less likely to buckle due to instability. In addition, the hard foam has a high energy absorption capacity and energy absorption efficiency. When subjected to external impact loads, it can absorb more energy and protect the carbon fiber porous buoyancy material from being damaged. The structure of the buoyancy material provided by the present invention achieves lightweight and has excellent water pressure resistance. In addition, the brittle weakness of the carbon fiber round tube structure can be improved according to the filling materials of different properties, so that it has excellent collision resistance.

[0059] The structural schematic diagram of a single carbon fiber round tube filled with filling material in the round tube filled carbon fiber buoyancy material provided by the present invention is as follows Figure 1 As shown. Figure 1 It can be seen that the interior of the carbon fiber tube (i.e., carbon fiber round tube) is filled with hard foam (i.e., filling material), and both ends of the carbon fiber tube are sealed with end caps.

[0060] The structural schematic diagram of the carbon fiber buoyancy material filled with a circular tube provided by the present invention is as follows Figure 2 As shown. Figure 2 It can be seen that the circular tube-filled carbon fiber buoyancy material provided by the present invention includes a hexagonal closest packed carbon fiber circular tube, an end cap, a hard foam (i.e., a filling material) and a resin (i.e., an epoxy resin); the hard foam is filled in the outermost circle of the hexagonal closest packed carbon fiber circular tube, and the resin is filled in the gap of the hexagonal closest packed carbon fiber circular tube.

[0061] The present invention also provides a method for preparing the carbon fiber buoyancy material filled with a circular tube as described in the above technical solution, comprising the following steps:

[0062] (1) rolling the carbon fiber prepreg into a tube and then curing it to obtain a carbon fiber round tube;

[0063] (2) using end caps and filling materials to fill and encapsulate part of the carbon fiber round tube obtained in step (1) to obtain an encapsulated filled carbon fiber round tube; using end caps to encapsulate the remaining carbon fiber round tube obtained in step (1) to obtain an encapsulated carbon fiber round tube;

[0064] (3) Arranging the encapsulated filled carbon fiber circular tube and the encapsulated carbon fiber circular tube obtained in the step (2) in a hexagonal closest packing manner, pouring epoxy resin and then curing to obtain a circular tube filled carbon fiber buoyancy material.

[0065] The present invention rolls the carbon fiber prepreg into a tube and then solidifies it to obtain a carbon fiber round tube.

[0066] The present invention preferably cuts the carbon fiber prepreg and then winds it into a tube. The present invention has no special limitation on the operation of the cutting and the size of the carbon fiber prepreg after cutting. The cutting technical solutions well-known to those skilled in the art can be adopted as long as the size of the carbon fiber round tube meets the requirements.

[0067] The present invention preferably lays multiple layers of carbon fiber prepregs and then winds them into a tube and cures them.

[0068] In the present invention, the thickness of the single-layer carbon fiber prepreg is preferably 0.1 - 0.2 mm, more preferably 0.15 mm.

[0069] The present invention has no special limitation on the number of layers of the carbon fiber prepreg, as long as the wall thickness of the prepared carbon fiber round tube is within the above range.

[0070] In the present invention, when the number of layers of the carbon fiber prepreg is 3, the laying angles of the multi-layer carbon fiber prepregs are preferably 90° / 90° / 0°; when the number of layers of the carbon fiber prepreg is greater than 3, the laying angles of the multi-layer carbon fiber prepregs are preferably repeated according to 90° / 90° / 0°.

[0071] The present invention controls the laying angles of the carbon fiber prepreg within the above range, which can improve the bending phenomenon of carbon fiber filaments during the preparation process and increase the forming rate of the carbon fiber round tube.

[0072] The present invention has no special limitation on the source of the carbon fiber prepreg, and commercially available products well-known to those skilled in the art can be adopted. In the present invention, the carbon fiber prepreg can specifically be the T700-12K / 50g carbon fiber prepreg produced by Shandong Kehang New Materials Co., Ltd.

[0073] The present invention preferably winds the tube through a tube winding device. In the present invention, the winding pressure is preferably 0.4 - 0.6 MPa, more preferably 0.5 MPa. The present invention has no special limitation on the model of the tube winding device and the operation of winding the tube. Commercially available tube winding devices well-known to those skilled in the art can be adopted and the winding can be carried out according to the conventional tube winding method.

[0074] After the tube winding is completed, the present invention preferably winds the wound product with a thermoplastic film and then cures it.

[0075] In the present invention, the thermoplastic film preferably includes a biaxially oriented polypropylene (BOPP) film, a polyethylene terephthalate (PET) film or a polyethylene (PE) film, more preferably a biaxially oriented polypropylene (BOPP) film.

[0076] In the present invention, the thickness of the thermoplastic film is preferably 0.4 - 0.6 mm, more preferably 0.5 mm; the width of the thermoplastic film is preferably 3 - 5 mm, more preferably 4 mm.

[0077] In the present invention, it is preferred to wind a layer of thermoplastic film on the outer surface of the product after coiling the tube by a winding device. There is no special limitation on the model of the winding device in the present invention, and conventional commercially available instruments and equipment can be used.

[0078] In the present invention, the winding pitch is preferably 1 - 3 mm, more preferably 2 mm; the winding tension is preferably 9 - 11 N, more preferably 10 N. In the present invention, the thermoplastic film will shrink upon heating during subsequent curing, providing pressure for the curing of the carbon fiber prepreg and ensuring the forming quality of the carbon fiber round tube. By controlling the type of thermoplastic film, the winding pitch, the tension, etc. within the above ranges in the present invention, the forming quality of the carbon fiber round tube can be further improved.

[0079] In the present invention, the curing temperature is preferably 120 - 140 °C, more preferably 130 °C; the curing time is preferably 80 - 100 min, more preferably 90 min. By controlling the curing temperature and time within the above ranges in the present invention, the carbon fiber prepreg can be fully cured.

[0080] In the present invention, the curing is preferably carried out in a curing furnace. There is no special limitation on the model of the curing furnace in the present invention, and conventional commercially available instruments and equipment can be used.

[0081] After obtaining the carbon fiber round tube, in the present invention, end caps and filling materials are used to fill and encapsulate a part of the carbon fiber round tube to obtain an encapsulated filled carbon fiber round tube; end caps are used to encapsulate the remaining carbon fiber round tube to obtain an encapsulated carbon fiber round tube.

[0082] In the present invention, end caps and filling materials are used to fill and encapsulate a part of the carbon fiber round tube to obtain an encapsulated filled carbon fiber round tube.

[0083] In the present invention, it is preferred to first encapsulate one end of the carbon fiber round tube with an end cap, then fill in the filling material, and then encapsulate the other end of the carbon fiber round tube with an end cap.

[0084] There is no special limitation on the filling operation in the present invention, as long as the filling material can be filled into the carbon fiber round tube.

[0085] In the present invention, the end cap is preferably bonded to the carbon fiber round tube with structural adhesive to encapsulate the carbon fiber round tube.

[0086] The present invention does not have any special limitations on the type and source of the structural adhesive. Using commercially available products well-known to those skilled in the art can ensure sufficient bonding between the end cap and the carbon fiber round tube. In the present invention, the structural adhesive may specifically be the J133 structural adhesive produced by the Petrochemical Research Institute of Heilongjiang Academy of Sciences.

[0087] The present invention does not have any special limitations on the operation of the bonding. Any technical solution well-known to those skilled in the art can be adopted.

[0088] The present invention uses an end cap to encapsulate the remaining carbon fiber round tube to obtain an encapsulated carbon fiber round tube.

[0089] In the present invention, the operation of the encapsulation is preferably the same as the above-mentioned encapsulation operation, and will not be elaborated here.

[0090] After obtaining the encapsulated filled carbon fiber round tube and the encapsulated carbon fiber round tube, the present invention arranges the encapsulated filled carbon fiber round tube and the encapsulated carbon fiber round tube in a hexagonal close-packed manner, pours epoxy resin and cures it to obtain a carbon fiber buoyancy material with round tube filling.

[0091] The present invention preferably arranges the encapsulated filled carbon fiber round tube and the encapsulated carbon fiber round tube in a hexagonal close-packed manner in a mold, and then pours epoxy resin into the mold.

[0092] In the present invention, the mold is preferably a regular hexahedron. In the present invention, after arranging the encapsulated filled carbon fiber round tube and the encapsulated carbon fiber round tube in a hexagonal close-packed manner at the center of the mold, the shortest distance between the outer edge of the carbon fiber round tube and the mold is preferably ≤1 mm, that is, the size of the mold is basically the same as the size of the carbon fiber round tube in hexagonal close packing, so as to avoid making the weight of the buoyancy material too heavy.

[0093] The present invention does not have any special limitations on the dosage of the epoxy resin, as long as the carbon fiber round tube can be just completely immersed.

[0094] In the present invention, the curing temperature is preferably room temperature; the curing time is preferably 20 - 26 h, more preferably 24 h. The present invention controls the curing temperature and time within the above ranges, which can make the epoxy resin fully cured.

[0095] After curing is completed, the present invention preferably demolds the cured product to obtain a carbon fiber buoyancy material with round tube filling.

[0096] The present invention does not have any special limitations on the demolding operation. Any technical solution well-known to those skilled in the art can be adopted.

[0097] The preparation method of the present invention has a simple process, high production efficiency, and broad application prospects.

[0098] The present invention also provides an application of the carbon fiber buoyancy material filled in a circular tube according to the above technical solution or the carbon fiber buoyancy material filled in a circular tube prepared by the preparation method according to the above technical solution in an underwater device.

[0099] The present invention has no special limitation on the operation of the application, and the technical solutions of the application well-known to those skilled in the art can be adopted.

[0100] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0101] Example 1

[0102] A carbon fiber buoyancy material filled in a circular tube, which consists of carbon fiber circular tubes in hexagonal close-packed structure, carbon fiber end caps, a filling material (foam aluminum, density 0.378 g / cm 3 , Young's modulus 1210 MPa, Shanghai Yirong Metal Materials Co., Ltd.) and epoxy resin (9350, composed of a matrix resin and a curing agent, with a mass ratio of 10:3. Among them, the matrix resin consists of bisphenol A epoxy resin 0164 and diluent XY622, with a mass ratio of 17:3, and the manufacturer is Nantong Xingchen Synthetic Materials Co., Ltd.; the two components of the curing agent are D230 and 593, with a mass ratio of 3:1, and the manufacturer is Chuzhou Huisheng Electronic Materials Co., Ltd.);

[0103] The filling material is filled in the outermost ring of the carbon fiber circular tubes in hexagonal close-packed structure, the end caps are encapsulated at both ends of the carbon fiber circular tubes in hexagonal close-packed structure, and the epoxy resin is filled in the voids of the carbon fiber circular tubes in hexagonal close-packed structure;

[0104] The inner diameter of a single carbon fiber circular tube is 13.5 mm, the wall thickness is 0.90 mm, and the length is 100 mm;

[0105] The shape of the end cap is a circular disc, the diameter of the circular disc is the same as the outer diameter of a single carbon fiber circular tube, and the thickness of the circular disc is 3.2 mm;

[0106] The filling material is cylindrical, the diameter of the filling material is the same as the inner diameter of the carbon fiber circular tube, and the length of the filling material is the same as the length of the carbon fiber circular tube;

[0107] The preparation method of the carbon fiber buoyancy material filled in the circular tube is as follows: (1) Cut the carbon fiber prepreg (T700-12K / 50g carbon fiber prepreg produced by Shandong Kehang New Materials Co., Ltd.) into a preset length. Lay multiple layers of carbon fiber prepregs repeatedly at the laying angles of 90° / 90° / 0°, with each layer having a thickness of 0.15 mm. Then, roll them into a carbon fiber circular tube through a tube rolling device, with the tube rolling pressure being 0.5 MPa. Next, wind a thermoplastic BOPP film (width: 4 mm, thickness: 0.5 mm) on its outer surface through a tape winding device, with the tape winding pitch being 2 mm and the tape winding tension being 10 N. Finally, place it in a curing furnace for heating and curing, with the curing temperature being 130 °C and the time being 90 min, to obtain a carbon fiber circular tube;

[0108] (2) Lay the carbon fiber prepreg (T700-12K / 50g carbon fiber prepreg produced by Shandong Kehang New Materials Co., Ltd.) repeatedly at the angles of 0° / 45° / 90° / -45°, with each layer having a thickness of 0.05 mm, to form a carbon fiber plate. Place it in a hot press can and heat and press it for curing under a vacuum state. The curing process is as follows: 80 °C for 30 min, then 130 °C for 90 min, with a constant pressure of 0.3 MPa throughout the process. After curing is completed, cut it to obtain an end cap;

[0109] (3) First, bond and encapsulate one end of the end cap and the carbon fiber circular tube with structural adhesive (J133), then fill in the filling material, and then bond and encapsulate the other end of the end cap and the carbon fiber circular tube with structural adhesive (J133) to obtain an encapsulated filled carbon fiber circular tube;

[0110] (4) Bond and encapsulate one end of the end cap and the carbon fiber circular tube with structural adhesive (J133), and then bond and encapsulate the other end of the end cap and the carbon fiber circular tube with structural adhesive (J133) to obtain an encapsulated carbon fiber circular tube;

[0111] (5) Arrange the encapsulated filled carbon fiber circular tubes and the encapsulated carbon fiber circular tubes in the mold in the manner of hexagonal closest packing, and then pour epoxy resin into the mold and cure it at room temperature for 24 h, and then demold to obtain the carbon fiber buoyancy material filled in the circular tube; The mold is a regular hexahedron. After arranging the encapsulated filled carbon fiber circular tubes and the encapsulated carbon fiber circular tubes in the center of the mold in the manner of hexagonal closest packing, the shortest distance between the outer edge of the carbon fiber circular tube and the mold is 1 mm, and the amount of epoxy resin used can just completely immerse the carbon fiber circular tube.

[0112] Example 2

[0113] Replace the filling material in Example 1 with composite foam SG1000 (density 0.4 g / cm 3 , Young's modulus 1000 MPa, Taizhou Zhongfu New Materials Technology Co., Ltd.), and other parameters are the same as those in Example 1.

[0114] Comparative Example 1

[0115] The filling material in Example 1 was omitted, and other parameters were the same as those in Example 1.

[0116] Comparative Example 2

[0117] The SBM-040H buoyancy material from Qingdao Marine Chemical Industry Research Institute, with a theoretical density of 0.40 g / cm 3 and a hydrostatic strength of 15 MPa.

[0118] Comparative Example 3

[0119] The SG1000 buoyancy material from Taizhou Zhongfu New Material Technology Co., Ltd., with a theoretical density of 0.40 g / cm 3 and a hydrostatic strength of 20 MPa.

[0120] The hydrostatic strength of the buoyancy materials in Examples 1-2 and Comparative Examples 1-3 was tested using the ASTM D2736-78 standard, and the results are as Figure 3 shown. As can be seen from Figure 3 , the theoretical density of the buoyancy material in Example 1 was 0.398 g / cm 3 , the water absorption rate < 0.1%, and the average hydrostatic strength was 30 MPa. The theoretical density of the buoyancy material in Example 2 was 0.403 g / cm 3 , the water absorption rate < 0.1%, and the average hydrostatic strength was 31 MPa. The theoretical density of the buoyancy material in Comparative Example 1 was 0.387 g / cm 3 , the water absorption rate < 0.1%, and the average hydrostatic strength was 21 MPa. Compared with the buoyancy materials in the comparative examples, the hydrostatic strength was improved. Compared with the unfilled buoyancy material in Comparative Example 1, the specific hydrostatic strength (the ratio of hydrostatic strength to density) of Example 1 was increased by about 38%, and that of Example 2 was increased by about 41%.

[0121] The impact resistance of the buoyancy materials in Examples 1-2 and Comparative Example 1 was tested using the ASTM D7136 standard, and the results are as Figure 4 shown. As can be seen from Figure 4 , the maximum impact load of Comparative Example 1 was 2.08*10 5 N, the maximum impact load of Example 1 was 3.05*10 5 N, and the maximum impact load of Example 2 was 2.79*10 5 N. Compared with the unfilled buoyancy material in Comparative Example 1, the maximum impact load of Example 1 was increased by about 46%, and that of Example 2 was increased by about 34%.

[0122] In summary, the buoyancy material provided by the present invention has better water pressure resistance and impact resistance, and has a low density and light weight.

[0123] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A carbon fiber buoyancy material filled with a circular tube, comprising a hexagonal closest packed carbon fiber circular tube, an end cap, a filling material and an epoxy resin; the filling material is filled in the outermost circle of the hexagonal closest packed carbon fiber circular tube, the end cap is encapsulated at both ends of the hexagonal closest packed carbon fiber circular tube, and the epoxy resin is filled in the gap of the hexagonal closest packed carbon fiber circular tube; the density of the filling material is less than 1g / cm 3 .

2. The carbon fiber buoyancy material filled with a circular tube according to claim 1, characterized in that: The inner diameter of a single carbon fiber round tube in the hexagonal closest packed carbon fiber round tube is 4 to 100 mm.

3. The carbon fiber buoyancy material filled with a circular tube according to claim 2, characterized in that: The wall thickness of a single carbon fiber round tube in the hexagonal closest packed carbon fiber round tube is 0.12 to 10 mm.

4. The carbon fiber buoyancy material filled with a circular tube according to claim 1, characterized in that: The material of the end cap is carbon fiber.

5. The carbon fiber buoyancy material filled with a circular tube according to claim 4, characterized in that: The end cap is in the shape of a disc; the diameter of the end cap is the same as the outer diameter of a single carbon fiber round tube in the hexagonal closest packed carbon fiber round tube.

6. The circular tube filled carbon fiber buoyancy material according to claim 1, characterized in that: The filling material is hard foam.

7. The carbon fiber buoyancy material filled with a circular tube according to claim 1, characterized in that: The curing temperature of the epoxy resin is room temperature, the room temperature viscosity of the epoxy resin is less than 220 MPa.s, the compression strength is greater than 95 MPa, and the compression modulus is greater than 3.5 MPa.

8. The method for preparing the carbon fiber buoyancy material filled with a circular tube according to any one of claims 1 to 7, comprising the following steps: (1) rolling the carbon fiber prepreg into a tube and then curing it to obtain a carbon fiber round tube; (2) using end caps and filling materials to fill and encapsulate part of the carbon fiber round tube obtained in step (1) to obtain an encapsulated filled carbon fiber round tube; using end caps to encapsulate the remaining carbon fiber round tube obtained in step (1) to obtain an encapsulated carbon fiber round tube; (3) Arranging the encapsulated filled carbon fiber circular tube and the encapsulated carbon fiber circular tube obtained in the step (2) in a hexagonal closest packing manner, pouring epoxy resin and then curing to obtain a circular tube filled carbon fiber buoyancy material.

9. The preparation method according to claim 8, characterized in that: The curing temperature in step (1) is 120-140° C., and the curing time is 80-100 min.

10. Use of the carbon fiber buoyancy material filled with a circular tube according to any one of claims 1 to 7 or the carbon fiber buoyancy material filled with a circular tube prepared by the preparation method according to claim 8 or 9 in underwater equipment.

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