Forming method of large-scale complex-structure buoyancy material

Abstract

The invention provides a forming method of a large-scale complex-structure buoyancy material, and relates to the technical field of composite material manufacturing, and the forming method specifically comprises the following steps: S1, manufacturing a skeleton according to a drawing; s2, preparing a buoyancy material; s3, performing block design on the buoyancy material according to the three-dimensional model of the grids on the framework; s4, the partitioned buoyancy materials are bonded to the corresponding positions of the framework plate grids in a vacuum mode; s5, vacuum filling is conducted on gaps between the framework plate grids and the buoyancy materials through resin; mould manufacturing is not needed, the cost is reduced, the single-time filling thickness is high and can reach 500 mm or above, the filling efficiency is high, meanwhile, the method can be used for forming buoyancy materials of different resin systems and different densities, the method is not limited by the structure size, the application range is wide, vacuum bonding and vacuum resin pouring are adopted, tiny flaws such as bubbles and micropores can be effectively eliminated, and the product quality is improved. The interface bonding quality is improved, it is ensured that the buoyancy material is free of gaps, bubbles and other defects, and the overall forming quality is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material manufacturing, and more specifically, to a forming method for a buoyancy material with a large and complex structure. Background Art

[0002] Buoyancy materials are one of the important supporting materials for current marine equipment and can provide good buoyancy for marine equipment. Currently, the main forming methods for buoyancy materials are casting molding and prefabrication and bonding molding. In the forming process of buoyancy materials with large and complex structures, the casting molding method has problems such as high density and low compressive strength, and the prefabrication and bonding molding method has problems such as low interfacial bonding strength, easy occurrence of bubbles and voids at the interface, and easy cracking under pressure. Therefore, the forming technology for buoyancy materials with large and complex structures is a difficult problem in the industry.

[0003] For example, Chinese Patent CN113861622A provides a method for preparing a buoyancy material with an integral forming process. This method uses a vacuum preparation mixing principle, fills it into a mold in batches, with a forming thickness of 5 cm each time, repeats the filling step, and after filling, uses a female mold to apply pressure and cure and demold to obtain a buoyancy material product. However, the forming thickness each time is relatively thin, only 5 cm, the efficiency is low, and a mold is required, resulting in high costs. It is not suitable for the forming of buoyancy materials with large and complex structures. In addition, bubbles and voids are easily generated during the casting filling process. Only pressure is applied in the final stage, and it is difficult to completely remove the bubbles. It is easy to crack under pressure, and there is no composite material protection on the outer layer, so it is easy to crack during long-term operation, resulting in a decrease in buoyancy. Summary of the Invention

[0004] In view of this, the present invention aims to propose a forming method for a buoyancy material with a large and complex structure to solve the problems of poor forming quality, low forming efficiency, and high cost of buoyancy materials in the prior art.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] A forming method for a buoyancy material with a large and complex structure, comprising the steps of:

[0007] S1: Making a skeleton according to the drawing;

[0008] S2: Making the buoyancy material;

[0009] S3: According to the three-dimensional model of the panel on the skeleton, performing a block design on the buoyancy material;

[0010] S4: Vacuum bonding the divided buoyancy material to the corresponding position of the skeleton panel;

[0011] S5: Using resin to perform vacuum perfusion on the gap between the skeleton panel and the buoyancy material.

[0012] Further, in step S2, chopped fibers are added during the batching stage of the buoyancy material and mixed evenly, and then molded by a compression molding process to obtain the buoyancy material.

[0013] Further, in step S4, the specific steps of vacuum bonding include:

[0014] S41: Apply an adhesive on the bonding surface of the buoyancy material;

[0015] S42: Fill and bond the buoyancy material to the corresponding position of the framework panel;

[0016] S43: Apply pressure evenly to the buoyancy material to squeeze out and scrape off the excess adhesive;

[0017] S44: Paste a release cloth on the surface of the framework and the buoyancy material;

[0018] S45: Arrange vacuum pipelines circumferentially outside the framework, and use a vacuum bag to seal the framework;

[0019] S46: Maintain the vacuum degree ≤ -0.09 MPa until the adhesive is completely cured;

[0020] S47: Remove the vacuum bag and vacuum pipelines.

[0021] Further, in step S5, the specific steps of vacuum resin infusion include:

[0022] S51: Paste a release cloth on the surface of the buoyancy material;

[0023] S52: Set the glue injection pipelines and vacuum pipelines evenly at intervals from top to bottom;

[0024] S53: Seal the framework with a double-layer bag film and maintain the vacuum degree ≤ -0.09 MPa;

[0025] S54: Open the glue injection pipeline, and when the resin liquid level no longer drops or resin flows out of the vacuum pipeline, close the glue injection pipeline and the vacuum pipeline, and the infusion is completed.

[0026] Further, it further includes step S6, where the surface of the buoyancy material is activated with a surfactant, then a fabric is laid on the surface of the buoyancy material, and glue injection pipelines are arranged circumferentially outside the framework for vacuum resin infusion to form a fiber-reinforced resin matrix composite material protective layer on the surfaces of the framework and the buoyancy material.

[0027] Further, the buoyancy material includes vinyl, hollow microspheres, and epoxy resin, and is molded by a compression molding process in a vacuum environment. The density of the buoyancy material is 300 - 700 kg / m 3 , and the compressive strength is 10 - 60 MPa.

[0028] Further, the specific manufacturing method of the adhesive is as follows: By weight, 100 parts of epoxy resin, 0.1 part of defoamer, and 1 part of coupling agent are sequentially added into a vacuum dispersion tank, stirred at 300 r / min for 10 min, then 3 parts of thixotropic agent are added and stirred at 1000 r / min for 20 min, and then 30 parts of hollow glass microspheres are added and stirred at 300 r / min for 10 min to form component A of the adhesive. The curing agent is component B. When in use, by weight, A:B = 134:40, and they are mixed evenly.

[0029] Further, component A and component B are mixed evenly and degassed under vacuum. The density of the adhesive is 0.5 - 0.98 kg / m 3 , and the viscosity of the resin is 100 - 500 cps.

[0030] Further, in step S1, the framework is made of steel, titanium alloy, aluminum alloy or fiber - reinforced composite material.

[0031] Further, the chopped fibers are soaked with a coupling agent, dried, and then added to the buoyancy material.

[0032] Compared with the prior art, the forming method of the large - scale complex - structure buoyancy material of the present invention has the following advantages:

[0033] 1) It is not necessary to make a mold, which reduces the cost. The single - filling thickness is high, up to more than 500 mm, and the filling efficiency is high. At the same time, it can be used for the forming of different resin systems and different - density buoyancy materials, is not limited by the structural size, and has a wide application range. By using vacuum bonding and vacuum resin infusion, it can effectively eliminate micro - defects such as air bubbles and micropores, improve the interfacial bonding quality, ensure that there are no gaps and air bubbles in the buoyancy material, and greatly improve the overall forming quality;

[0034] 2) After adding chopped fibers, the strength of the buoyancy material can be effectively enhanced, the mechanical properties of the material are significantly improved, and it performs better under pressure;

[0035] 3) By using vacuum bonding and vacuum infusion, micro - defects such as air bubbles and micropores can be further eliminated, the buoyancy material fits more closely with the framework grid, the structural stability is better, which helps to improve the overall pressure resistance and anti - cracking performance of the buoyancy material. Specific Embodiments

[0036] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below.

[0037] Example 1

[0038] A forming method of a large - scale complex - structure buoyancy material, including the steps:

[0039] S1: Fabricate the framework according to the drawings;

[0040] S2: Fabricate the buoyancy material;

[0041] S3: Based on the 3D model of the panel grids on the framework, perform block design on the buoyancy material;

[0042] S4: Vacuum bond the segmented buoyancy material to the corresponding positions of the framework panel grids;

[0043] S5: Use resin to perform vacuum perfusion on the gaps between the framework panel grids and the buoyancy material.

[0044] The forming method of the buoyancy material for large complex structures described in this application does not require mold fabrication, reducing costs. The single - filling thickness is high, up to more than 500 mm, and the filling efficiency is high. At the same time, it can be used for the forming of buoyancy materials with different resin systems and different densities, is not limited by structural dimensions, and has a wide range of applications. By using vacuum bonding and vacuum resin perfusion, it can effectively eliminate small defects such as air bubbles and micropores, improve the interfacial bonding quality, ensure that there are no gaps and air bubbles in the buoyancy material, and greatly improve the overall forming quality.

[0045] Preferably, in step S5, after filling and bonding the buoyancy material to the framework panel grids, the linear shape of the buoyancy material is trimmed by machining or grinding to achieve the required linear accuracy.

[0046] As a preferred example of this application, in step S2, short - cut fibers are added and evenly mixed during the batching stage of the buoyancy material, and then it is formed by a compression molding process to obtain the buoyancy material.

[0047] Specifically, after adding short - cut fibers, the compressive strength of the buoyancy material is increased by more than 2 MPa, and the compressive modulus is increased by more than 0.1 MPa, making it perform better under pressure and better meet the actual use requirements.

[0048] Preferably, the fiber material is cut into sections to obtain short - cut fibers, and the short - cut fibers are glass fibers, carbon fibers, or a compound of glass fibers and carbon fibers.

[0049] As a preferred example of this application, in step S4, the specific steps of vacuum bonding include:

[0050] S41: Apply an adhesive on the bonding surface of the buoyancy material;

[0051] S42: Fill and bond the buoyancy material to the corresponding positions of the framework panel grids;

[0052] S43: Apply uniform pressure to the buoyancy material to squeeze out and scrape off the excess adhesive;

[0053] S44: Stick a release cloth on the surface of the framework and the buoyancy material;

[0054] S45: Circumferentially arrange vacuum pipelines outside the framework and seal the framework with a vacuum bag;

[0055] S46: Keep the vacuum degree ≤ -0.09 MPa until the adhesive is completely cured;

[0056] S47: Remove the vacuum bag and the vacuum pipelines.

[0057] Specifically, by uniformly applying pressure to extrude the excess adhesive, the adhesive can be more evenly distributed, enhancing the bonding effect; in a vacuum environment, the air bubbles in the adhesive are easier to discharge. Keeping the vacuum degree ≤ -0.09 MPa until the adhesive is completely cured can effectively eliminate the air bubbles at the bonding interface. Combined with subsequent vacuum resin infusion, it can further eliminate tiny defects such as air bubbles and micropores; during the vacuum bonding process, the vacuum bag sealing and uniform pressure application can make the buoyancy material fit more closely with the framework grid, with better structural stability, which helps to improve the overall pressure resistance and anti-cracking performance of the buoyancy material.

[0058] Preferably, a low-density, water-resistant, pressure-resistant, and high-strength adhesive is used to ensure the bonding quality of the interface.

[0059] As a preferred example of the present application, in step S5, the specific steps of vacuum resin infusion include:

[0060] S51: Stick a release cloth on the surface of the buoyancy material;

[0061] S52: Uniformly set injection pipelines and vacuum pipelines at intervals from top to bottom;

[0062] S53: Seal the framework with a double-layer bag film and keep the vacuum degree ≤ -0.09 MPa;

[0063] S54: Open the injection pipeline. When the resin liquid level no longer drops or resin flows out of the vacuum pipeline, close the injection pipeline and the vacuum pipeline, and the infusion is completed.

[0064] Specifically, this setting can enable the resin to be evenly and fully filled into the gaps between the framework grid and the buoyancy material. Conducting resin infusion in a vacuum environment can further eliminate tiny defects such as air bubbles and micropores, improving the internal structure quality of the buoyancy material, thereby enhancing its pressure resistance, anti-cracking performance, etc. The buoyancy material formed by this method has no damage after the alternating pressure test and is highly reliable. After inspection and testing, there are no pores, air bubbles and other defects on the surface and inside of the buoyancy material, and the bonding strength of the synchronous sample interface is 15.3 MPa.

[0065] Preferably, in step S52, the interval between the injection pipeline and the vacuum pipeline is 600 mm.

[0066] As a preferred example of the present application, it further includes step S6. The surface of the buoyancy material is activated with a surfactant, then a fabric is laid on the surface of the buoyancy material, and a glue injection pipeline is arranged circumferentially outside the framework for vacuum resin infusion, so as to form a fiber-reinforced resin matrix composite material protective layer on the surfaces of the framework and the buoyancy material.

[0067] Specifically, activating the surface of the buoyancy material with a surfactant can significantly improve the bonding strength of the interface between the buoyancy material and the protective layer, making the protective layer more tightly combined with the buoyancy material and not easily separated.

[0068] The protective layer can seal the micropores on the surface of the buoyancy material, prevent the intrusion of external substances such as moisture, effectively protect the buoyancy material, and improve the pressure resistance of the buoyancy material. After passing the assessment test, when the same kind of buoyancy material is subjected to an alternating pressure test, there is no damage. When there is no composite material protective layer on the surface of the buoyancy material, the water absorption rate is 10.8%, and when there is a composite material protective layer on the surface of the buoyancy material, the water absorption rate is 0.2%, and the reliability is improved. At the same time, this protective layer can protect the buoyancy material, prevent it from being mechanically damaged during use, and extend its service life.

[0069] Preferably, the surfactant is composed of vinyl, epoxy resin and an interfacial agent, and the interfacial agent is silane coupling agent KH550 or KH560.

[0070] Preferably, the surfactant is composed of vinyl, epoxy-modified vinyl resin and an interfacial agent, and the interfacial agent is silane coupling agent KH550 or KH560.

[0071] Preferably, the thickness of the fiber-reinforced resin matrix composite material protective layer is 1 - 20 mm.

[0072] As a preferred example of the present application, the buoyancy material includes vinyl, hollow microspheres and epoxy resin, and is manufactured and formed by a molding process in a vacuum environment. The density of the buoyancy material is 300 - 700 kg / m 3 , and the compressive strength is 10 - 60 MPa.

[0073] Specifically, the hollow microspheres help to reduce the density of the buoyancy material and provide buoyancy, while components such as epoxy resin ensure the strength of the buoyancy material. This setting enables the buoyancy material to have both a certain buoyancy and sufficient strength. Manufacturing and forming by a molding process in a vacuum environment helps to remove the bubbles inside the buoyancy material, making the structure of the buoyancy material denser and ensuring the stability and consistency of the buoyancy material.

[0074] Preferably, the buoyancy material includes vinyl, hollow microspheres and epoxy-modified vinyl resin.

[0075] As a preferred example of the present application, the adhesive formulation by weight is: 100 parts of epoxy resin, 0.1 part of defoamer, 30 parts of hollow glass microspheres, 3 parts of thixotropic agent, 1 part of interface agent, and 40 parts of curing agent;

[0076] The specific production method of the adhesive is as follows: By weight, 100 parts of epoxy resin, 0.1 part of defoamer, and 1 part of interface agent are sequentially added to a vacuum dispersion tank and stirred at 300 r / min for 10 min. Then, 3 parts of thixotropic agent are added and stirred at 1000 r / min for 20 min. Next, 30 parts of hollow glass microspheres are added and stirred at 300 r / min for 10 min to form Component A of the adhesive, and the curing agent is Component B. When in use, by weight, A:B = 134:40, and they are mixed evenly.

[0077] Specifically, epoxy resin, as the main component, provides a good bonding foundation. Adding a defoamer can effectively eliminate the bubbles in the adhesive, avoid affecting the bonding quality due to the presence of bubbles, and ensure close fitting between the adhesive and the buoyancy material and the skeleton. The interface agent enhances the affinity of the adhesive with the surfaces of different materials and improves the bonding strength between the interfaces; the thixotropic agent can improve the rheological properties of the adhesive, making it easier to operate during application and bonding and not prone to flowing. The addition of hollow glass microspheres reduces the weight of the adhesive to a certain extent and also helps to improve the comprehensive properties of the adhesive, such as reducing density and improving heat insulation; dividing the adhesive into Components A and B and mixing them evenly in a specific ratio during use is convenient for storage and transportation and can ensure that the performance of the adhesive is in the best state during use.

[0078] Preferably, the defoamer can be an organosilicon defoamer or a polyether defoamer.

[0079] Preferably, the thixotropic agent is fumed silica.

[0080] Preferably, the curing agent is an amine curing agent.

[0081] As a preferred example of the present application, after mixing Components A and B evenly and performing vacuum degassing, the density of the adhesive is 0.5 - 0.98 kg / m 3 , and the viscosity of the resin is 100 - 500 cps.

[0082] Specifically, vacuum degassing can remove the bubbles in the adhesive, avoid forming defects at the bonding interface, improve the interface bonding strength, prevent cracking under pressure, and improve the overall reliability of the buoyancy material; controlling the density of the adhesive to be 0.5 - 0.98 kg / m 3, the viscosity of the resin is 100 - 500 cps, which can endow the adhesive with good fluidity and workability. This setting can ensure that the adhesive is evenly distributed during the application and pouring processes, without being affected by being too heavy or too light for operation. It is easy to apply and pour, and will not be too thin to cause dripping, facilitating use in different operation links and ensuring the construction quality.

[0083] As a preferred example of this application, in step S1, the framework is made of steel, titanium alloy, aluminum alloy or fiber-reinforced composite material.

[0084] Specifically, these materials all have good processing properties. Steel can be made into various shapes through welding, machining, etc. Aluminum alloy is easy to cast and process. Fiber-reinforced composite materials can be made into frameworks with complex shapes according to different molds and molding processes, meeting the diverse design requirements of buoyancy materials for large and complex structures and facilitating production and manufacturing.

[0085] Preferably, the tolerance of the framework is controlled within ±2 mm. When using metal materials, the framework is made by welding. After welding, the weld needs to be ground smooth.

[0086] As a preferred example of this application, the chopped fibers are soaked in an interfacial agent and then dried, and then added to the buoyancy material. The chopped fibers are used to enhance the strength of the buoyancy material and can also improve the bonding strength between the buoyancy material and the protective layer.

[0087] Specifically, the interfacial agent can form an active film on the surface of the chopped fibers, enhancing the affinity between the fibers and the buoyancy material. After the chopped fibers are added to the buoyancy material, this active film can promote better bonding between the fibers and the surrounding materials, improving the interfacial bonding strength and enabling the chopped fibers to play a more effective reinforcing role; the chopped fibers treated with the interfacial agent can be more evenly dispersed in the buoyancy material, effectively enhancing the strength of the buoyancy material. After adding the chopped fibers, both the compressive strength and compressive modulus of the buoyancy material are improved, significantly enhancing the mechanical properties of the material and making it perform better under pressure.

[0088] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A method for forming a large complex structure buoyancy material, characterized in that: Includes steps: S1: Make the skeleton according to the drawing; S2: making buoyancy materials; S3: According to the three-dimensional model of the plate grid on the frame, the buoyancy material is designed in blocks; S4: vacuum bonding the divided buoyancy materials to corresponding positions of the frame panels; S5: Use resin to vacuum infuse the gap between the frame plate grid and the buoyancy material.

2. The molding method of large-scale complex structure buoyancy material according to claim 1, characterized in that: In step S2, short-cut fibers are added to the batching stage of the buoyancy material and mixed evenly, and then molded by a molding process to obtain the buoyancy material.

3. The molding method of large-scale complex structure buoyancy material according to claim 1, characterized in that: In step S4, the specific steps of vacuum bonding include: S41: Apply adhesive to the bonding surface of the buoyancy material; S42: Fill and bond the buoyancy material to the corresponding position of the frame plate grid; S43: Apply the buoyancy material evenly, squeeze out and scrape off the excess adhesive; S44: pasting release cloth on the surface of the frame and the buoyancy material; S45: Arranging a vacuum pipeline in a circular direction outside the frame, and sealing the frame with a vacuum bag; S46: Maintain vacuum degree ≤-0.09MPa until the adhesive is completely cured; S47: Remove the vacuum bag and vacuum line.

4. The method for forming a large-scale complex structure buoyancy material according to claim 1, characterized in that: In step S5, the specific steps of vacuum resin infusion include: S51: Pasting a release cloth on the surface of the buoyancy material; S52: Glue injection pipelines and vacuum pipelines are evenly spaced from top to bottom; S53: Use double-layer bag film to seal the frame and maintain the vacuum degree ≤-0.09MPa; S54: Open the glue injection pipeline. When the resin liquid level stops dropping or resin flows out of the vacuum pipeline, close the glue injection pipeline and the vacuum pipeline, and the filling is completed.

5. The molding method of large-scale complex structure buoyancy material according to claim 1, characterized in that: The method further includes step S6, wherein a surfactant is used to activate the surface of the buoyancy material, a fabric is then laid on the surface of the buoyancy material, a glue injection pipeline is arranged in an annular direction outside the skeleton, and vacuum resin infusion is performed to form a fiber-reinforced resin-based composite material protective layer on the surface of the skeleton and the buoyancy material.

6. The molding method of large-scale complex structure buoyancy material according to claim 1, characterized in that: The buoyancy material comprises vinyl, hollow microspheres and epoxy resin, and is manufactured by a molding process under a vacuum environment. The density of the buoyancy material is 300-700 kg / m 3 , the compression strength is 10~60MPa.

7. The molding method of large-scale complex structure buoyancy material according to claim 3, characterized in that: The specific preparation method of the adhesive is as follows: according to weight parts, 100 parts of epoxy resin, 0.1 parts of defoaming agent and 1 part of interface agent are added into a vacuum dispersion tank in sequence, stirred at 300r / min for 10 minutes, and then 3 parts of thixotropic agent are added, stirred at 1000r / min for 20 minutes, and then 30 parts of hollow glass microbeads are added, stirred at 300r / min for 10 minutes to form adhesive component A, and the curing agent is component B. When using, the weight parts are A:B=134:40 and mixed evenly.

8. The method for forming a large-scale complex structure buoyancy material according to claim 7, characterized in that: Mix component A and component B evenly and vacuum degas. The density of the adhesive is 0.5~0.98kg / m 3 , the viscosity of the resin is 100~500cps.

9. The method for forming a large-scale complex structure buoyancy material according to claim 1, characterized in that: In step S1, the skeleton is made of steel, titanium alloy, aluminum alloy or fiber-reinforced composite material.

10. The molding method of large-scale complex structure buoyancy material according to claim 2, characterized in that: The chopped fibers are soaked in an interface agent and then dried, and then added into the buoyancy material.