Preparation method of buoyancy material for shallow water area and prepared buoyancy material

Abstract

The invention relates to a preparation method of a buoyancy material for a shallow water area and the prepared buoyancy material. The preparation method comprises the following steps: S1, pretreating a foam core material; s2, blending a resin coating; s3, uniformly coating the resin coating on the surface of the foam core material; s4, homogenization treatment: blowing the resin coating coated on the surface of the foam core material to be flat; s5, curing the surface layer resin, wherein the thickness of the cured resin is 0.1-1.0 mm; and S6, the operation of the steps S3 to S5 is repeated for 2-3 times, the resin thickness is 0.2-0.4 mm after the large aperture of the surface of the foam core material is filled with the resin coated on the first layer, the resin thickness is 0.4-1 mm after the small aperture of the surface of the foam core material is filled with the resin coated on the second layer, and the resin thickness of the resin coated on the third layer is 0.8-2 mm. According to the method disclosed by the invention, the buoyancy material with low density, low water absorption and high strength can be prepared, and the buoyancy material can be suitable for being used at different depths of a shallow water layer water area in a water depth range of 100m-300m.

Description

Technical Field

[0001] The present invention relates to the technical field of buoyancy material preparation, and specifically relates to a method for preparing a buoyancy material for shallow waters and the prepared buoyancy material. Background Art

[0002] Buoyancy materials provide buoyancy for underwater operation equipment with their low-density characteristics, and at the same time should have the properties of high strength and low water absorption to ensure the normal progress of underwater operations. Currently, the main R & D entities of buoyancy materials are chemically foamed buoyancy materials and hollow glass microsphere composite lightweight buoyancy materials. The hollow glass microsphere composite lightweight buoyancy materials are mainly used in deep waters. Affected by the filling rate of glass microspheres, it is very difficult to produce buoyancy materials with a density below 0.36 g / cm 3 This restricts their application scope in shallow water areas. At the same time, raw materials such as hollow glass microspheres are expensive, resulting in high production costs. There are many civilian scenarios in shallow water areas, and the cost issue is a major concern in material selection.

[0003] The special structure of traditional foam materials makes their density lower, but at the same time, the pore distribution will lead to an increase in water absorption and a decrease in strength. Therefore, it is difficult to directly use a single foam material as an underwater buoyancy material and it is difficult to provide long-term stable buoyancy for underwater equipment. Expanded polystyrene has a low density and is mostly used as a surface buoy, fishing float, etc. in the shallow surface water environment within 10 m, but its strength is low and it cannot withstand the water pressure in deeper waters. The selection and application of buoyancy materials in the water depth range of 100 m - 300 m still need to be developed. Summary of the Invention

[0004] Aiming at the technical problems existing in the above-mentioned prior art, the present invention provides a method for preparing a buoyancy material for shallow waters and the prepared buoyancy material, which can effectively solve the technical problems existing in the above-mentioned prior art.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing a buoyancy material for shallow waters, comprising the following steps:

[0007] S1, surface pretreatment of the foam core material;

[0008] S2, resin coating formulation;

[0009] S3, coating, uniformly coating the above-mentioned resin coating on the surface of the foam core material, the thickness of the coated resin is 0.2 mm - 2 mm, and the coating time is 0.1 - 1 h;

[0010] S4, surface homogenization treatment, blowing the resin coating coated on the surface of the foam core material flat and removing the excess resin coating;

[0011] S5. Cure the surface resin and solidify the resin on the surface of the foam core material by means of equipment intervention or natural air drying. The thickness of the solidified resin is 0.1 mm to 1.0 mm.

[0012] S6. Repeat the operations of steps S3 to S5 two to three times. After the resin coated in the first layer fills the large pores on the surface of the foam core material, the resin thickness is 0.2 to 0.4 mm. After the resin coated in the second layer fills the small pores on the surface of the foam core material, the resin thickness is 0.4 to 1 mm. The thickness of the resin coated in the third layer is 0.8 to 2 mm.

[0013] After the last curing in step S6 is completed, there is a local coating in step S7. For the areas on the surface of the foam core material where pores can still be observed, repeat steps S3 to S5 locally until all the pores on the surface are closed.

[0014] After the local coating in step S7, there is a cleaning step S8. After the resin on the surface of the buoyancy material is completely cured, enter step S8 for cleaning, and clean it with one or several of 96% alcohol, acetone or other organic solvents to wash away the residual resin oily substances on the surface of the completely cured buoyancy material.

[0015] The surface pretreatment in step S1 includes a grinding treatment in step S11 and a cleaning treatment in step S12. The grinding treatment is to grind the surface of the foam core material to make the size meet the design requirements while reducing the surface roughness and the irregularity of the cutting edge. The cleaning treatment is to use an air gun to blow or a brush to sweep to remove the powder and dust remaining after grinding on the surface of the foam core material.

[0016] When preparing the resin coating in step S2, accurately weigh the resin and the corresponding additives and fully mix and stir all components evenly.

[0017] The coating in step S3 can evenly cover the resin on the surface of the foam core material by spraying, manual brushing or immersion. The surface homogenization treatment in step S4 can blow the coated resin flat by means of blowing or spin-drying.

[0018] The curing in step S5 can select the corresponding curing method according to the characteristics of the resin coating used. If the resin coating used is a photo-curing resin, each surface of the foam core material needs to be irradiated under an ultraviolet lamp for 20 s to 30 s until the material surface stops generating heat. If the resin coating used is an unsaturated polyester resin, vinyl resin or epoxy resin, it needs to be air-dried in a natural environment until the resin surface is no longer sticky and completely cured. If phenolic resin, bismaleimide resin or polyimide resin is used, curing requires high-temperature treatment. Among them, the curing temperature of phenolic resin is 150 - 200 °C, the curing temperature of bismaleimide resin is 180 - 250 °C, and the curing temperature of polyimide resin is gradually increased to more than 300 °C.

[0019] The coating in step S3 is realized by the following coating device, and the coating device includes:

[0020] A conveying mechanism, including a conveyor belt driven by a motor, and a plurality of mounting components are evenly arranged at intervals in the front and rear directions on the belt surface of the conveyor belt. The mounting components include two positioning plates fixedly mounted on both sides of the belt surface of the conveyor belt;

[0021] A clamping mechanism for clamping and fixing the foam core material, including a rotating shaft mounted on the positioning plate. A corresponding sleeve member is slidably sleeved on the outer side of the inner end of the rotating shaft. The end and the top of the sleeve member not connected to the rotating shaft are arranged in an unsealed state. The end of the sleeve member connected to the rotating shaft is provided with a corresponding iron guide rod through a corresponding connecting plate. The iron guide rod is slidably inserted into a sleeve fixed on the rotating shaft through a corresponding first spring. The first spring makes the sleeve member have a tendency to move outward;

[0022] A feeding mechanism. When the foam core material is clamped between the two sleeve members, the rotating shaft and the foam core material seal the two end portions of the sleeve member, so that the sleeve member forms a container for receiving the coating material. The feeding mechanism is arranged on the front side of the conveyor belt and includes two feeding pipes with the discharge ports facing directly above the container. The feeding pipes are externally connected to the coating material source;

[0023] A curing mechanism for quickly solidifying the coating material in the container, including two ultraviolet lamps arranged directly above the containers of the sleeve members. The ultraviolet lamps are arranged between the feeding mechanism and the spraying mechanism, and a corresponding protective cover is provided at the position of the conveyor belt where the curing mechanism is located;

[0024] A spraying mechanism for spraying a corresponding coating material on the surface of the foam core material, including an isolation cover arranged at the rear side of the conveyor belt and at least one coating material spray head arranged in the isolation cover. The coating material spray head is externally connected to a coating material container through a corresponding conduction pipe and a liquid pump. Preferably, it includes two coating material spray heads arranged left and right and inclined inward;

[0025] A rotating mechanism for driving the clamping mechanism to rotate. The rotating shaft is rotatably mounted on the positioning plate through a corresponding bearing. The rotating mechanism includes a roller fixedly connected to the outer end of the rotating shaft and a group of connecting plates fixedly mounted on the conveyor belt. The connecting plates are respectively mounted on both sides of the conveyor belt at the position of the spraying mechanism. When the foam core material moves to the position of the connecting plate, the roller is tangent to the upper surface of the connecting plate, and the rotating shaft drives the foam core material to rotate while moving forward;

[0026] A self-locking mechanism is used to lock the outward-moving sleeve member, comprising a vertical rod installed on the sleeve member through a corresponding L-shaped plate, the vertical rod is inserted up and down on the L-shaped plate and a corresponding iron limit block is fixedly installed on the top end thereof, the outer side of the vertical rod is sleeved with a second spring whose two ends are respectively fixed on the L-shaped plate and the vertical rod, the second spring is arranged in a compressed state, the lower end of the vertical rod can be moved left and right in a guide groove on the rotating shaft, and the end of the guide groove is recessed inwardly and provided with a corresponding fixing hole.

[0027] A release mechanism, used to release the fixation of the foam core material by the clamping mechanism, comprising a group of lower magnets respectively installed on both sides of the conveyor belt located at the rear side of the spraying mechanism. When the foam core material moves to the position of the lower magnets, the iron guide rod drives the sleeve member to move outwards to break away from the clamping fixation of the foam core material under the magnetic attraction of the lower magnets. The first spring is compressed, and the vertical rod moves with the sleeve member and moves into the fixing hole under the elastic force of the second spring, thereby fixing the sleeve member;

[0028] The unlocking mechanism is used to release the fixation of the sleeve member by the self-locking mechanism, and comprises a group of upper magnets respectively installed on both sides of the conveyor belt located on the front side of the feed pipe. When the foam core material is placed on the clamping mechanism, the iron limit block moves up and out of the fixing hole under the magnetic attraction force of the upper magnet, and the sleeve member moves outward under the elastic force of the first spring to abut against the end of the foam core material and clamp the foam core material.

[0029] The buoyancy material is made of a foam core material coated with multiple layers of resin coating by the above-mentioned preparation method, and the foam core material has an inner core density of 100-300kg / m 3 The low-density foam material is a PVC foam core material, a PMI foam core material or a PET foam core material, and the resin coating is a light-curing resin, an unsaturated polyester resin, a vinyl resin or an epoxy resin, a phenolic resin, a bismaleimide resin or a polyimide resin, or a mixture of several of them.

[0030] Advantages of the present invention:

[0031] 1) The method of the present invention uses low-density foam as the inner core and coats the surface with multiple layers of resin for closed-cell treatment. The operation process is relatively simple, the product performance can meet the actual use requirements, effectively reduce costs, and is suitable for mass production. More importantly, the prepared buoyancy material not only has the low-density characteristics of traditional foam materials, but also has a density of 100-300kg / m 3Moreover, the water absorption rates of the buoyancy materials prepared therefrom can be as low as 0.21% and 0.26% after standing for 2 hours under a pressure of 2.3 MPa and standing for 3 hours under a pressure of 2.5 MPa, respectively. By simple processing, efficient closed pores are achieved, reducing the water absorption rate of the foam material and increasing its strength. Thus, the prepared buoyancy materials can be applied to different depths in the shallow water layer of the water area with a depth range of 100 m - 300 m.

[0032] 2) The present invention sequentially pre-treats, layer-by-layer coats, gradually coats, homogenizes, and cures the surface of the low-density foam, and optimally controls the resin thickness, coating time, curing time, and coating times for each layer of coating. The pore sizes on the surface of the foam core material are unevenly distributed and the aperture gap is obvious. Through thickness control and adjustment in the present invention, after the resin of the first layer of coating fills the large-aperture pores on the surface of the foam core material, the resin thickness is 0.2 - 0.4 mm. The first thin-layer spraying fills the large-aperture pores, forming uniform pores on the surface of the foam core material. Many foam regions separated by the pores form tensile and rigid connections through the cured resin, enhancing the strength of the surface of the foam core material. Moreover, through the thin-layer filling and coating of the first layer, the shrinkage variable of the subsequent coating can be effectively reduced, further improving the flatness, coating quality, and stability of resin adhesion of the coating, and avoiding the influence of unevenness and subsequent resin adhesion caused by many local contractions due to large pores in the case of a relatively thick coating. The second spraying fills the small-aperture pores on the surface of the foam core material and controls its coating thickness within 0.4 - 1 mm, which can form a smooth surface on the surface of the foam core material, improve the integrity of the coating surface, and promote the adhesion of subsequent spraying. The resin thickness of the third layer of coating is 0.8 - 2 mm. By strengthening the covering coating, the strength of the buoyancy material is further improved and the water absorption performance is reduced.

[0033] Secondly, the resin is homogenized by means of blowing flat or spin-drying, which can not only remove the excess resin coating, reduce sagging, but also make the resin thickness on the surface of the core material tend to be consistent, ensuring the flatness of the material surface and the application and adhesion of subsequent coatings. Thirdly, by means of continuing the coating after complete curing, it can effectively avoid the influence of external factors on the original structure when the resin is in a semi-cured state, resulting in an incomplete uniformity of the cured product or incomplete hardening inside while hardening outside, and finally partial peeling occurs. Furthermore, the adhesion of the resin material and the strength of the buoyancy material are improved. On the basis of improving the surface uniformity of the foam core material by the filling and coating of the first-layer thin layer, finally, the entire core material is completely coated and the micro-pores are filled through 2 - 3 repetitions of the coating - homogenization - curing treatment, improving the strength of the buoyancy material while ensuring the bonding property.

[0034] 3) Furthermore, while grinding and processing the foam core material into the dimensions required by the design through cutting, its surface roughness and irregularity are reduced, and the dust on its surface is removed, thereby enhancing the bonding degree between the resin and the core material surface and reducing the influence of particulate materials such as dust on the resin adhesion; then, the prepared resin coating is evenly applied to the surface of the foam core material by brushing or spraying.

[0035] 4) Traditionally, regardless of the spraying and feeding method, there will be corresponding uncoated clamping areas on the surface of the foam core material, which need to be filled after most of the coating is completed. However, due to the small clamping area, it is difficult to coat this area, which easily leads to incomplete coating and causes gaps; if the clamping area is increased, and the coated area is clamped again after rotation for coating other areas, it will cause marks on the coated area and affect the coating effect. Therefore, in the present invention, the coating operation is performed through an optimized coating device. A corresponding non-standard sleeve part is provided on the rotating shaft of the clamping mechanism for fixing the foam core material. The end and top of the sleeve part not connected to the rotating shaft are set in an unclosed state; when the foam core material is clamped between two rotating shafts, the two ends of the sleeve part are closed by the rotating shaft and the foam core material, so that the sleeve part forms a container for receiving the coating. The coating is filled into the container through the feed pipe and the curing mechanism, and the coating is pre-cured on the foam core material. Then, the sleeve part is moved out by magnetically adsorbing the iron guide rod. The cured coating column connects the foam core material and the rotating shaft. Subsequently, other areas of the foam core material are coated. After the coating is completely finished, the excess part of the cured coating column is cut off. In this way, compared with the traditional filling, the connection between the coating column and the coating layer is more firm and tight, thereby ensuring low water absorption filtration and improving the bonding performance of its coating, and the cutting process is simpler and easier to operate. Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the coating device in the invention.

[0037] Figure 2 is Figure 1 a schematic structural diagram of the clamping mechanism and the unlocking mechanism in

[0038] Figure 3 is Figure 1 a sectional view of the curing mechanism and the clamping mechanism in

[0039] Figure 4 is Figure 1 a sectional view of the spraying mechanism and the clamping mechanism in (a schematic diagram of the state where the self-locking mechanism locks the sleeve part)

[0040] Figure 5 is Figure 1 a schematic structural diagram of the sleeve part in

[0041] In the attached drawings: conveying mechanism 1, conveyor belt 101, positioning plate 102, clamping mechanism 2, rotating shaft 201, sleeve part 202, iron guide rod 203, first spring 204, sleeve 205, feed pipe 3, ultraviolet lamp 4, protective cover 5, isolation cover 6, paint spray head 7, rotating mechanism 8, roller 801, connecting plate 802, self-locking mechanism 9, vertical rod 901, second spring 903, iron limit block 902, lower magnet 10, upper magnet 11. Detailed implementation manners

[0042] For the convenience of those skilled in the art to understand, the structure of the present invention will be further described in detail below in conjunction with the accompanying drawings:

[0043] A preparation method of buoyancy material for shallow waters includes the following steps:

[0044] S1, surface pretreatment of the foam core material;

[0045] S2, resin coating formulation;

[0046] S3, coating, evenly coating the above resin coating on the surface of the foam core material, the thickness of the coated resin is 0.2 mm to 2 mm, and the coating time is 0.1 to 1 h;

[0047] S4, surface homogenization treatment, blowing the resin coating coated on the surface of the foam core material flat, removing the excess resin coating, reducing sagging, and ensuring the flatness of the material surface;

[0048] S5, curing the surface resin, solidifying the resin on the surface of the foam core material by means of equipment intervention or natural air drying, and the thickness of the cured resin is 0.1 mm to 1.0 mm;

[0049] S6, repeating the operations of steps S3 to S5 2 to 3 times, wherein the resin thickness is 0.2 to 0.4 mm after the first layer of coated resin fills the large pores on the surface of the foam core material, the resin thickness is 0.4 to 1 mm after the second layer of coated resin fills the small pores on the surface of the foam core material, and the resin thickness of the third layer is 0.8 to 2 mm.

[0050] After the last curing in step S6 is completed, there is also step S7 of local coating, and the areas on the surface of the foam core material where pores can still be observed are locally repeated with steps S3 to S5 until all the surface pores are closed.

[0051] After the local coating in step S7, there is also step S8 of cleaning. After the resin on the surface of the buoyancy material is completely cured, it enters step S8 of cleaning, and is cleaned with one or several of 96% alcohol, acetone or other organic solvents to wash away the residual resin oily substances on the surface of the completely cured buoyancy material.

[0052] The surface pretreatment in step S1 includes step S11 grinding treatment and step S12 cleaning treatment; the grinding treatment is to grind the surface of the foam core material to make the size meet the design requirements while reducing the surface roughness, reducing the irregularity of the cutting edge, and improving the bonding degree between the resin and the core material surface; the cleaning treatment is to use a gas gun to blow or a brush to sweep to remove the powder and dust remaining on the surface of the foam core material after grinding, and reduce its influence on the resin adhesion.

[0053] When preparing the resin coating in step S2, accurately weigh the resin and the corresponding additives, and fully mix and stir all components evenly.

[0054] The coating in step S3 can uniformly cover the resin on the surface of the foam core material by spraying, manual brushing or dipping; the surface homogenization treatment in step S4 can blow the coated resin flat by blowing or spin-drying.

[0055] For the curing in step S5, the corresponding curing method can be selected according to the characteristics of the resin coating used. If the resin coating used is a photocurable resin, each surface of the foam core material needs to be irradiated under an ultraviolet lamp for 20s - 30s until the surface of the material stops generating heat; if the resin coating used is an unsaturated polyester resin, vinyl resin or epoxy resin, it needs to be air-dried in a natural environment until the surface of the resin is no longer sticky and is completely cured; if phenolic resin, bismaleimide resin or polyimide resin is used, high-temperature treatment is required for curing, where the curing temperature of phenolic resin is 150 - 200°C, the curing temperature of bismaleimide resin is 180 - 250°C; the curing temperature of polyimide resin is gradually increased to above 300°C in steps.

[0056] The method of the present invention uses low-density foam as the inner core and coats multiple layers of resin on the surface for closed-cell treatment. The operation process is relatively simple, the product performance can meet the actual use requirements, the cost is effectively reduced, and it is suitable for mass production. More importantly, the prepared buoyancy material not only has the low-density characteristic of traditional foam materials, and the density can reach 100 - 300 kg / m 3 , and the water absorption rate of the buoyancy material prepared by it can be as low as 0.21% and 0.26% after standing for 2 h under the condition of 2.3 MPa pressure and standing for 3 h under the condition of 2.5 MPa pressure. By simple processing, efficient closed-cell is achieved, the water absorption rate of the foam material is reduced and the strength is increased, and then the prepared buoyancy material can be applied to different depths in the shallow water layer of 100 m - 300 m water depth range.

[0057] The present invention adopts a process of sequentially pre-treating, layer-by-layer coating, step-by-step coating, homogenizing and curing the surface of low-density foam, and optimally controlling the resin thickness, coating time, curing time and coating times for each layer of coating. The pore sizes on the original surface of the foam core material are uneven and there is a significant difference in pore diameters. Through thickness control adjustment in the present invention, after the resin of the first layer of coating fills the large pore diameters on the surface of the foam core material, the resin thickness is 0.2 - 0.4 mm. The first thin-layer spraying fills the large pore diameters, so that a uniform pore structure is formed on the surface of the foam core material. Many foam regions separated by the pores form tensile and rigid connections through the cured resin, enhancing the strength of the surface of the foam core material. Moreover, through the thin-layer filling and coating of the first layer, the shrinkage variable of the subsequent coating can be effectively reduced, further improving the flatness of the coating, the coating quality and the stability of resin adhesion, and avoiding the influence of unevenness and subsequent resin adhesion caused by many local shrinkages due to large pores in the case of relatively thick coating; the second spraying fills the small pore diameters on the surface of the foam core material and controls its coating thickness within 0.4 - 1 mm, which can make the surface of the foam core material smooth, improve the integrity of the coating surface, and promote the adhesion of subsequent spraying; the resin thickness of the third layer of coating is 0.8 - 2 mm, and the strength of the buoyancy material is further improved and the water absorption performance is reduced by strengthening the covering coating.

[0058] Secondly, the resin is homogenized by means of blowing flat or spin-drying. This can not only remove the excess resin coating and reduce sagging, but also make the resin thickness on the surface of the core material tend to be consistent, ensuring the flatness of the material surface and the application and adhesion of subsequent coatings; thirdly, by means of continuing to coat after complete curing, it can effectively avoid the influence of external factors on the original structure when the resin is in a semi-cured state, which may cause the cured product to be not completely uniform or the inside is not hardened while the outside is hardened, and finally partial peeling occurs, thereby enhancing the adhesion of the resin material and the strength of the buoyancy material. On the basis of improving the surface uniformity of the foam core material by the filling and coating of the first thin layer, finally, the entire core material is completely coated and the micro-pores are filled by repeating the coating - homogenization - curing process 2 - 3 times, improving the strength of the buoyancy material while ensuring the bonding property.

[0059] Furthermore, while cutting and grinding the foam core material into the size required by the design, its surface roughness and irregularity are reduced, and the dust on its surface is removed, thereby enhancing the bonding degree between the resin and the surface of the core material and reducing the influence of dust and other particulate materials on resin adhesion; then, the prepared resin coating is evenly applied to the surface of the foam core material by brushing or spraying.

[0060] A buoyancy material for shallow waters, the buoyancy material is formed by coating multiple layers of resin coatings on a foam core material through the above preparation method. The foam core material has an inner core density of 100 - 300 kg / m 3The low-density foam material is one of PVC foam core material, PMI foam core material or PET foam core material, and the resin coating is one or a mixture of several of photocurable resin, unsaturated polyester resin, vinyl resin or epoxy resin, phenolic resin, bismaleimide resin or polyimide resin.

[0061] Example 1

[0062] A preparation method of buoyancy material for shallow waters, which is used for the Harvard-style cable buoy at a water depth of 200 meters. It includes using high-strength PVC foam as the buoyancy material inner core. Each hemisphere surface of the buoy is evenly coated with vinyl resin, and there are grooves inside to place nylon clamps for clamping cables. The major axis diameter of the buoy is 280 mm, and the minor axis diameter is 200 mm. The density of the PVC foam core material is 200 kg / m 3 , and the production of the buoy includes the following steps:

[0063] S1, surface pretreatment of the foam core material; cutting the foam blank material group according to the design drawing to make the size meet the design requirements while reducing the surface roughness and the irregularity of the cutting edge to improve the bonding degree between the resin and the core material surface. Then use an air gun to blow and remove the powder and dust remaining on the surface of the foam core material after grinding to reduce its impact on resin adhesion;

[0064] S2, resin coating formulation, adjusting the vinyl resin formula, with the proportion of accelerator and curing agent both being 1%. Accurately weigh and mix and stir all components evenly, and control the total weight at 300 g;

[0065] S3, coating, assembling the formulated vinyl resin into a spray gun, controlling the spray pressure of the spray gun at 0.3 - 0.5 Mpa, the spray distance at 15 - 30 cm, and the moving speed of the spray gun at 30 - 60 cm / s. Uniformly spray the vinyl resin on the surface of the PVC foam, with the thickness of the coated resin being 0.2 mm to 2 mm, and the coating time being 0.5 h;

[0066] S4, surface homogenization treatment, using an air gun to blow and spray the vinyl resin coated on the surface of the PVC foam core material to make it flat, reducing sagging and particles, and ensuring the flatness of the material surface;

[0067] S5, curing the surface resin, adopting the method of natural air drying and static curing to solidify the resin on the surface of the foam core material, and the thickness of the cured resin is 0.1 mm to 1.0 mm;

[0068] S6. Repeat the operations in steps S3 - S5 twice until the number of resin layers reaches 3. The resin thickness of the first layer after filling the large - diameter pores on the surface of the foam core is 0.2 - 0.4 mm. The resin thickness of the second layer after filling the small - diameter pores on the surface of the foam core is 0.4 - 1 mm. The resin thickness of the third layer is 0.8 - 2 mm;

[0069] S7. Local coating. Locally repeat steps S3 - S5 for the areas on the surface of the foam core where pores can still be observed until all the surface pores are closed;

[0070] S8. Cleaning. After the resin is completely cured, clean the surface of the float ball with 96% alcohol to wash away the residual resin oily substances on the surface of the fully - cured buoyancy material.

[0071] Example 2

[0072] A preparation method of a shallow - water buoyancy material for an irregular - polygon buoyancy block at a water depth of 100 m, including using a high - strength PET foam material as the inner core, and the entire surface of the buoyancy block is uniformly coated with a photocurable resin. The density of the PET foam core is 130 kg / m 3 , and the resin uses a PA - like photocurable resin. The production of the buoyancy block includes the following steps:

[0073] S1. Surface pretreatment of the foam core; Process the PET foam standard block into a blank with the required shape on a numerically - controlled machine tool, reduce the surface roughness while making the dimensions meet the design requirements, reduce the irregularity of the cutting edge to improve the bonding degree between the resin and the core surface, and then use an air gun to blow and remove the powder and dust remaining on the surface of the foam core after grinding to reduce its impact on resin adhesion;

[0074] S2. Preparation of the PA - like photocurable resin;

[0075] S3. Coating. Apply the PA - like photocurable resin on the surface of the PET foam evenly with a brush. The thickness of the coated resin is 0.2 mm - 2 mm, and the coating time is 0.1 - 1 h;

[0076] S4. Surface homogenization treatment. Level the PA - like photocurable resin coated on the surface of the PET foam core by spinning - dry to remove the excess resin, reduce sagging, and ensure the flatness of the material surface;

[0077] S5. Cure the surface resin. Use an ultraviolet lamp to irradiate each surface evenly. The irradiation time for each surface is 20 s - 30 s to cure the surface resin until the entire surface of the material no longer generates heat. The thickness of the cured resin is 0.1 mm - 1.0 mm;

[0078] S6. Repeat the operations in steps S3 - S5 two times until the number of resin layers reaches three. The resin thickness of the first layer after coating and filling the large pores on the surface of the foam core material is 0.2 - 0.4 mm. The resin thickness of the second layer after coating and filling the small pores on the surface of the foam core material is 0.4 - 1 mm. The resin thickness of the third layer is 0.8 - 2 mm.

[0079] S7. Local coating: Locally repeat steps S3 - S5 for the areas on the surface of the foam core material where pores can still be observed until all surface pores are closed.

[0080] S8. Cleaning: After the resin is completely cured, clean the surface of the buoyancy block with 96% alcohol to wash away the residual resin oily substances on the surface of the completely cured buoyancy material.

[0081] The difference between Example 3 and Example 1 is that the PET foam core material with a density of 130 kg / m 3 The difference between Example 4 and Example 2 is that the PVC foam core material with a density of 200 kg / m 3 The difference between Example 5 and Example 2 is that a tough photocurable resin is used.

[0082] The buoyancy materials prepared in Examples 1 - 5 were respectively left standing for 2 h and 3 h under pressures of 2.3 MPa and 2.5 MPa, and the corresponding water release rates were respectively detected. The specific detection results are shown in Tables 1 and 2 (where the foam type 200Y is made of PVC material with a density of 200 kg / m 3 , 100Y is made of PET material with a density of 130 kg / m 3 ):

[0083] Table 1 Water absorption of the buoyancy material after standing for 2 h under a pressure of 2.3 MPa

[0084]

[0085] Table 2 Water absorption of the buoyancy material after standing for 3 h under a pressure of 2.5 MPa

[0086]

[0087] As can be seen from Tables 1 and 2, by using the method of the present invention, with a low - density foam as the inner core and coating multiple layers of resin on the surface for closed - cell treatment, the operation process is relatively simple. The product performance can meet the actual use requirements, effectively reduce costs, and is suitable for mass production. More importantly, the prepared buoyancy material not only has the low - density characteristic of traditional foam materials, and the density can reach 100 - 300 kg / m 3 , especially when the PET foam core material has a density of 130 kg / m 3The buoyancy material prepared from PA-like photocurable resin has a water absorption rate as low as 0.21% and 0.26% after standing for 2 hours under a pressure of 2.3 MPa and standing for 3 hours under a pressure of 2.5 MPa. By simple processing, high-efficiency closed pores are achieved, reducing the water absorption rate and increasing the strength of the foam material. Furthermore, the prepared buoyancy material can be applied to different depths in the shallow water layer of the water area with a depth range of 100 m - 300 m.

[0088] Example Six

[0089] Reference Figures 1-5 A method for preparing a buoyancy material for shallow water areas, wherein the coating in step S3 is realized based on the following coating device. The coating device includes:

[0090] A conveying mechanism 1, including a conveyor belt 101 driven by a motor. A plurality of mounting components are evenly distributed at intervals in the front and rear directions on the belt surface of the conveyor belt 101. The mounting components include two positioning plates 102 fixedly mounted on both sides of the belt surface of the conveyor belt 101.

[0091] A clamping mechanism 2 for clamping and fixing the foam core. It includes a rotating shaft 201 mounted on the positioning plate 102. A corresponding sleeve member 202 is slidably sleeved on the outer side of the inner end of the rotating shaft 201. The end and the top of the sleeve member 202 not connected to the rotating shaft 201 are arranged in an unclosed state. The end of the sleeve member 202 connected to the rotating shaft 201 is provided with a corresponding iron guide rod 203 through a corresponding connecting plate. The iron guide rod 203 is slidably inserted into a sleeve 205 fixed on the rotating shaft 201 through a corresponding first spring 204. The first spring 204 gives the sleeve member 202 a tendency to move outwards.

[0092] A feeding mechanism. When the foam core is clamped between the two sleeve members 202, the rotating shaft 201 and the foam core close the two end parts of the sleeve member 202, so that the sleeve member 202 forms a container for receiving the coating. The feeding mechanism is arranged on the front side of the conveyor belt 101 and includes two feeding pipes 3 with the discharge ports facing directly above the container. The feeding pipes 3 are externally connected to the coating source.

[0093] A curing mechanism for quickly solidifying the coating in the container. It includes two ultraviolet lamps 4 arranged directly above the containers of the sleeve members 202. The ultraviolet lamps 4 are arranged between the feeding mechanism and the spraying mechanism, and a corresponding protective cover 5 is provided at the position of the conveyor belt 101 where the curing mechanism is located.

[0094] Spraying mechanism, used to spray corresponding coatings on the surface of the foam core material, including an isolation cover 6 arranged at the rear side of the conveyor belt 101, and at least one coating spray head 7 arranged inside the isolation cover 6. The coating spray head 7 is externally connected to a coating container through a corresponding conduction pipe and a liquid pump. Preferably, it includes two coating spray heads 7 arranged left and right and inclined inward;

[0095] Rotating mechanism 8, used to drive the clamping mechanism 2 to rotate. The rotating shaft 201 is rotatably installed on the positioning plate 102 through corresponding bearings. The rotating mechanism 8 includes a roller 801 fixedly connected to the outer end of the rotating shaft 201, and a set of connecting plates 802 fixedly installed on the conveyor belt 101. The connecting plates 802 are respectively installed on both sides of the conveyor belt 101 at the spraying mechanism. When the foam core material moves to the connecting plate 802, the roller 801 is tangent to the upper surface of the connecting plate 802, and the rotating shaft 201 drives the foam core material to rotate while moving forward;

[0096] Self-locking mechanism 9, used to lock the outwardly moved sleeve member 202, including a vertical rod 901 installed on the sleeve member 205 through a corresponding L-shaped plate. The vertical rod 901 is vertically inserted through the L-shaped plate and a corresponding iron limiting block 902 is fixedly installed at its top end. A second spring 903 with both ends respectively fixed on the L-shaped plate and the vertical rod 901 is sleeved outside the vertical rod 901. The second spring 903 is arranged in a compressed state. The lower end of the vertical rod 901 can move left and right in a guide groove on the rotating shaft 201, and a corresponding fixing hole is recessed inward at the end of the guide groove.

[0097] Release mechanism, used to release the fixation of the clamping mechanism 2 on the foam core material, including a set of lower magnets 10 respectively installed on both sides of the conveyor belt 101 at the rear side of the spraying mechanism. When the foam core material moves to the position of the lower magnet 10, the iron guide rod 203 drives the sleeve member 202 to move outward to release the clamping and fixation of the foam core material under the magnetic attraction of the lower magnet 10. The first spring 204 is compressed, and the vertical rod 901 moves with the sleeve member 202 and moves into the fixing hole under the elastic force of the second spring 903, thereby fixing the sleeve member 202;

[0098] The unlocking mechanism is used to release the fixation of the self-locking mechanism 9 on the sleeve part 202, and includes a set of upper magnets 11 respectively installed on both sides of the conveyor belt 101 located in front of the feed pipe 3. When the foam core material is placed on the clamping mechanism 2, the iron limit block 902 moves upward under the magnetic attraction of the upper magnet 11 to disengage from the fixing hole, and the sleeve part 202 moves outward under the elastic force of the first spring 204 and abuts against the end of the foam core material to clamp and fix the foam core material. The reset elastic force of the first spring 204 is greater than the magnetic attraction of the upper magnet 902 on the limit block 902, so as to ensure that when the vertical rod 901 moves upward to disengage from the fixation of the positioning hole, the sleeve part 202 can move towards the foam core material under the elastic force of the first spring 204 for stable clamping.

[0099] Traditionally, no matter what kind of spraying feeding method is used, there will be corresponding uncoated clamping areas on the surface of the foam core material, and it is necessary to fill them after most of the coating is completed. However, due to the small clamping area, it is not easy to coat this area, which easily leads to incomplete coating and causes gaps. If the clamping area is increased, after coating, the direction is rotated and clamped to coat other areas, which will cause marks on the coated area and affect the coating effect. Therefore, the present invention performs the coating action through an optimized coating device, and a corresponding non-standard sleeve part 202 is provided on the rotating shaft 201 of the clamping mechanism 2 for fixing the foam core material. The end and the top of the sleeve part 202 not connected to the rotating shaft 201 are arranged in an unsealed state. When the foam core material is clamped between the two rotating shafts 201, the rotating shaft 201 and the foam core material seal the two end parts of the sleeve part 202 to form a container for receiving the coating material. The coating material is filled into the container through the feed pipe 3 and the curing mechanism, and the coating material is pre-cured on the foam core material. Then, the iron guide rod 203 is driven to move outward by magnetic attraction to drive the sleeve part 202 to move outward. The cured coating material column connects the foam core material and the rotating shaft 201. Subsequently, other areas of the foam core material are coated. After the coating is completely finished, the redundant part of the cured coating material column is cut off. In this way, compared with the traditional filling, the connection between the coating material column and the coating layer is more firm and tight, which can ensure low water absorption filtration and improve the bonding performance of its coating layer, and the cutting treatment is simpler and easier to operate.

[0100] 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 retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. Preparation method of buoyancy material for shallow water area, characterized in that, It includes the following steps: S1, surface pretreatment of the foam core material; S2, resin coating formulation; S3, coating, uniformly coating the above-mentioned resin coating on the surface of the foam core material, the thickness of the coated resin is 0.2 mm to 2 mm, and the coating time is 0.1 to 1 h; S4, surface homogenization treatment, blowing the resin coating coated on the surface of the foam core material flat and removing the excess resin coating; S5, curing the surface resin, solidifying the resin on the surface of the foam core material by means of equipment intervention or natural air drying, and the thickness of the cured resin is 0.1 mm to 1.0 mm; S6, repeat the operations of steps S3 to S5 2 to 3 times, where the resin thickness is 0.2 to 0.4 mm after the first layer of coated resin fills the large pores on the surface of the foam core material, and the resin thickness is 0.4 to 1 mm after the second layer of coated resin fills the small pores on the surface of the foam core material, and the resin thickness of the third layer is 0.8 to 2 mm.

2. The preparation method of the buoyancy material for shallow waters according to claim 1, wherein After the last curing in step S6 is completed, there is a local coating in step S7, and steps S3 to S5 are locally repeated for the areas on the surface of the foam core material where pores can still be observed until all the surface pores are closed.

3. The preparation method of the buoyancy material for shallow waters according to claim 2, wherein, After the local coating in step S7, there is a step S8 cleaning. After the resin on the surface of the buoyancy material is completely cured, it enters step S8 cleaning, and it is cleaned with one or several of 96% alcohol, acetone or other organic solvents to wash away the residual resin oily substances on the surface of the completely cured buoyancy material.

4. The preparation method of the buoyancy material for shallow waters according to claim 1, characterized in that The surface pretreatment in step S1 includes step S11 grinding treatment and step S12 cleaning treatment; the grinding treatment is to grind the surface of the foam core material to make the size meet the design requirements while reducing the surface roughness and reducing the irregularity of the cutting edge; the cleaning treatment is to use an air gun to blow or a brush to sweep to remove the powder and dust remaining after grinding on the surface of the foam core material.

5. The preparation method of the buoyancy material for shallow waters according to claim 1, characterized in that, When formulating the resin coating in step S2, accurately weigh the resin and the corresponding additives, and fully mix and stir all components evenly.

6. The preparation method of the buoyancy material for shallow waters according to claim 1, characterized in that, The coating in step S3 can uniformly cover the resin on the surface of the foam core material by spraying, manual brushing or soaking; the surface homogenization treatment in step S4 can blow the coated resin flat by means of blowing or spin-drying.

7. The preparation method of the buoyancy material for shallow waters according to claim 1, wherein, For the curing in step S5, the corresponding curing method can be selected according to the characteristics of the resin coating used. If the resin coating used is a photocurable resin, each surface of the foam core material needs to be irradiated under an ultraviolet lamp for 20 s to 30 s until the material surface stops generating heat; if the resin coating used is an unsaturated polyester resin, vinyl resin or epoxy resin, it needs to be air-dried in a natural environment until the resin surface is no longer sticky and is completely cured; if phenolic resin, bismaleimide resin or polyimide resin is used, high-temperature treatment is required for curing, where the curing temperature of phenolic resin is 150 - 200 °C, the curing temperature of bismaleimide resin is 180 - 250 °C; the curing temperature of polyimide resin is ramped up to above 300 °C.

8. The preparation method of the buoyancy material for shallow waters according to claim 1, wherein The coating in step S3 is realized by the following coating device, and the coating device includes: The conveying mechanism includes a conveyor belt driven by a motor. A plurality of mounting components are evenly arranged at intervals in the front and rear directions on the belt surface of the conveyor belt. The mounting components include two positioning plates fixedly mounted on both sides of the belt surface of the conveyor belt. The clamping mechanism is used to clamp and fix the foam core material. It includes a rotating shaft mounted on the positioning plate. A corresponding sleeve member is slidably sleeved on the outer side of the inner end of the rotating shaft. The end and the top of the sleeve member not connected to the rotating shaft are arranged in an unsealed state. The end of the sleeve member connected to the rotating shaft is provided with a corresponding iron guide rod through a corresponding connecting plate. The iron guide rod is slidably inserted into a sleeve fixed on the rotating shaft through a corresponding first spring. The first spring gives the sleeve member a tendency to move outwards. When the foam core material is clamped between two sleeve members, the rotating shaft and the foam core material close the two end parts of the sleeve member, so that the sleeve member forms a container for receiving the coating material. The feeding mechanism is arranged on the front side of the conveyor belt and includes two feeding pipes with the discharge ports facing directly above the container. The feeding pipes are externally connected to the coating material source. The curing mechanism is used to quickly solidify the coating material in the container and includes two ultraviolet lamps arranged directly above the containers of the sleeve members. The ultraviolet lamps are arranged between the feeding mechanism and the spraying mechanism, and a corresponding protective cover is provided at the position of the conveyor belt where the curing mechanism is located. The spraying mechanism is used to spray the corresponding coating material on the surface of the foam core material and includes a shielding cover arranged at the rear side of the conveyor belt and at least one coating material spray head arranged in the shielding cover. The coating material spray head is externally connected to a coating material container through a corresponding conduction pipe and a liquid pump. Preferably, it includes two coating material spray heads arranged left and right and inclined inwards. The rotating mechanism is used to drive the clamping mechanism to rotate. The rotating shaft is rotatably mounted on the positioning plate through a corresponding bearing. The rotating mechanism includes a roller fixedly connected to the outer end of the rotating shaft and a group of connecting plates fixedly mounted on the conveyor belt. The connecting plates are respectively mounted on both sides of the conveyor belt at the position of the spraying mechanism. When the foam core material moves to the connecting plate, the roller is tangent to the upper surface of the connecting plate, and the rotating shaft drives the foam core material to rotate while moving forward. The self-locking mechanism is used to lock the outwardly moved sleeve member and includes a vertical rod mounted on the sleeve member through a corresponding L-shaped plate. The vertical rod is vertically inserted through the L-shaped plate, and a corresponding iron limiting block is fixedly mounted at the top end thereof. A second spring with both ends respectively fixed on the L-shaped plate and the vertical rod is sleeved on the outer side of the vertical rod. The second spring is arranged in a compressed state. The lower end of the vertical rod is slidably arranged in a guide groove on the rotating shaft, and a corresponding fixing hole is recessed inwardly at the end of the guide groove.

9. The preparation method of the buoyancy material for shallow waters according to claim 8, characterized in that, The coating device further includes A release mechanism, used to release the fixation of the foam core material by the clamping mechanism, comprising a group of lower magnets respectively installed on both sides of the conveyor belt located at the rear side of the spraying mechanism. When the foam core material moves to the position of the lower magnets, the iron guide rod drives the sleeve member to move outwards to break away from the clamping fixation of the foam core material under the magnetic attraction of the lower magnets. The first spring is compressed, and the vertical rod moves with the sleeve member and moves into the fixing hole under the elastic force of the second spring, thereby fixing the sleeve member; The unlocking mechanism is used to release the fixation of the sleeve member by the self-locking mechanism, and comprises a group of upper magnets respectively installed on both sides of the conveyor belt located on the front side of the feed pipe. When the foam core material is placed on the clamping mechanism, the iron limit block moves up and out of the fixing hole under the magnetic attraction force of the upper magnet, and the sleeve member moves outward under the elastic force of the first spring to abut against the end of the foam core material and clamp the foam core material.

10. A buoyancy material for shallow waters, characterized in that, The buoyancy material is formed by coating a foam core material with a multi-layer resin coating by the preparation method described in any one of claims 1-9. The foam core material is a low-density foam material with an inner core density of 100-300 kg / m 3 . The low-density foam material is one of PVC foam core material, PMI foam core material or PET foam core material. The resin coating is one or a mixture of several of photocurable resin, unsaturated polyester resin, vinyl resin, epoxy resin, phenolic resin, bismaleimide resin or polyimide resin.

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