A rigid noise reduction rock wool board for a ship and a preparation method thereof

Abstract

The present application relates to the technical field of rock wool board, in particular to a rigid noise reduction rock wool board for ships and a preparation method thereof.The present application overcomes the problem that the noise reduction performance and mechanical performance of traditional rock wool boards cannot be considered simultaneously.The present application sprays amino-modified hollow glass microspheres into a basalt fiber flow, and through a pendulum felt laying and pleating curing, a high-density rock wool core layer with a vertical fiber structure is prepared.A protective layer is prepared by hot pressing a hard aluminum foil and a PET film.The present application prepares an epoxy-polyurethane interpenetrating network adhesive containing nano-graphene and modified silicon dioxide.Finally, through gluing and laminating and segmented temperature control curing, the rigid noise reduction rock wool board for ships is obtained by compounding each layer.The present application significantly improves the comprehensive performance of the board through the synergistic support and sound scattering effect of microspheres and vertical fibers, in combination with a constrained damping structure and an interface chemical bonding technology.

Description

Technical Field

[0001] This invention relates to the field of rock wool board technology, specifically to a rigid noise-reducing rock wool board for ships and its preparation method. Background Technology

[0002] Ships navigate in the high-humidity, high-salt-spray, and continuously vibrating marine environment, requiring their cabin partitions and deck lining materials to possess Class A non-combustible fire resistance, excellent thermal insulation capabilities, and good acoustic comfort. Rock wool, as an inorganic mineral fiber material, has become a mainstream choice for ship outfitting due to its natural fire-resistant properties and porous sound-absorbing structure. With continuous technological advancements, higher standards are being set for the lightweight, environmental friendliness, and overall mechanical performance of rock wool boards.

[0003] Current marine rock wool boards generally suffer from a technical bottleneck where acoustic and mechanical properties are difficult to balance. Traditional rock wool fibers are distributed in horizontal layers, resulting in low compressive and tensile strength, and the surface is easily dented. To compensate for strength, heavy galvanized steel sheets are often used as the face sheet, significantly increasing the ship's weight and causing difficulties in cutting during installation, leading to significant waste of scrap materials. Furthermore, traditional rock wool mainly relies on its porous sound absorption, but it is poor at isolating the low-frequency vibration noise unique to the ship's engine room. When the rock wool becomes damp or is subjected to long-term vibration, the fibers are prone to pulverization and settling, resulting in a "funnel effect" in sound insulation. Although existing metal composite panels have sufficient rigidity, the poor acoustic impedance matching between the metal face sheet and the rock wool core material actually reduces sound insulation at certain frequencies.

[0004] To address this, a rigid noise-reducing rock wool board for ships and its preparation method are proposed. Summary of the Invention

[0005] The purpose of this invention is to design a rigid noise-reducing rock wool board for marine applications and its preparation method. This invention involves spraying amino-modified hollow glass microspheres into a basalt fiber stream, followed by pendulum-laid felting and pleating curing to obtain a high-density rock wool core layer with a vertical fiber structure; hot-pressing rigid aluminum foil and PET film together to form a protective layer; preparing an epoxy-polyurethane interpenetrating network adhesive containing nano-graphene and modified silica; and finally, bonding the layers together through adhesive lamination and segmented temperature-controlled curing to obtain the rigid noise-reducing rock wool board for marine applications. This invention significantly improves the overall performance of the board through the synergistic support and sound scattering effect of the microspheres and vertical fibers, combined with a constrained damping structure and interfacial chemical bonding technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing rigid noise-reducing rock wool boards for ships, comprising the following steps:

[0008] The basalt mixture is melted and centrifuged into fibers. Modified glass microspheres are premixed with phenolic resin solution and sprayed into the fibers. After collecting and pleating the fibers, the rock wool core layer is solidified and formed.

[0009] One side of a rigid aluminum foil is corona treated and then hot-pressed with a PET film to obtain a protective layer.

[0010] An adhesive is obtained by adding epoxy resin, nano-graphene sheets and modified silica to a polyurethane prepolymer and stirring.

[0011] Adhesive is applied to both sides of the rock wool core layer and a protective layer is attached. After segmented curing, a rigid noise-reducing rock wool board for ships is obtained.

[0012] Preferably, the specific preparation method of the rock wool core layer is as follows: 80 parts of basalt and 20 parts of diabase are mixed to obtain a basalt mixture; 8-10 parts of water-soluble phenolic resin (solid content 48%, pH value = 8.5-9.0, viscosity at 25℃ 20-40 mPa·s), 6-8 parts of modified glass microspheres, 0.5 parts of an aqueous emulsion of polymethylhydrosiloxane (solid content 35%, obtained by emulsifying a mixture of polymethylhydrosiloxane and Span-80 in a mixture of deionized water and Tween-80), and 0.3 parts of a naphthenic oil emulsion (solid content 50%, as a...) are added... Dust-proof oil) is mixed and stirred to obtain a mixed emulsion; the basalt mixture is placed in a cupola furnace, the temperature is controlled at 1400-1500℃, and the speed of the four-roll centrifuge is 4500-5000r / min. During the continuous stirring process, the mixed emulsion is sprayed into the fiber flow at the centrifuge roller spinning point (the temperature is lower here); then the pendulum is laid with a oscillation frequency of 50-60 times / min; the fiber layer is folded and squeezed by a differential speed pleating machine, the pleat ratio is controlled at 4:1, and it is put into a curing oven, the temperature is controlled at 190℃, and it is held for 20 minutes to obtain a rock wool core layer with an average thickness of 50mm.

[0013] Preferably, the modified glass microspheres are prepared as follows: 200 parts of anhydrous ethanol and 20 parts of deionized water are added to a reaction vessel and stirred until homogeneous. Glacial acetic acid is added dropwise while stirring to adjust the pH of the solution to approximately 4.5. Then, 1.8 parts of KH-550 (CAS: 919-30-2) are added, and the mixture is stirred at low speed for 40 minutes at room temperature to obtain the modified solution. 95-105 parts of hollow glass microspheres (true density: 0.20-0.30 g / cm³) are then added. 3 Particle size: 30-50μm) is slowly added to the modification solution, the temperature is raised to 60-70℃, the rotation speed is controlled within 100r / min, and the mixture is stirred at a constant temperature for 2h. After the reaction is completed, the slurry is filtered to obtain a microsphere filter cake. The filter cake is placed in a forced-air drying oven and dried at 80℃ for 1h. Then the temperature is raised to 120℃ and kept at that temperature for 2h. After natural cooling, it is passed through a 60-mesh sieve to obtain modified glass microspheres.

[0014] Preferably, the protective layer is prepared by: corona treatment of one side of a rigid aluminum foil (H18, 50 μm) to make its dyne value greater than 38 dyne / cm, thus obtaining a pretreated aluminum foil; and coating the treated surface of the pretreated aluminum foil with polyurethane adhesive at a coating amount of 3-4 g / m. 2 The coating is placed in an oven and dried by gradually increasing the temperature from 65°C to 85°C at a rate of 5°C / min. Then, the coated surface is bonded to a PET film (15μm) and hot-pressed. The temperature of the composite steel roller is 70-80°C and the composite pressure is 0.5MPa. Finally, it is cured at 50°C for 64 hours to obtain the protective layer.

[0015] Preferably, the adhesive is prepared by mixing and dispersing 38-42 parts of E-51 bisphenol A type epoxy resin (epoxy value 0.51), 4 parts of dicyandiamide (particle size <10μm), 0.1-0.5 parts of nano-graphene sheets (thickness <5nm, sheet diameter 2-5μm) and 0.1 parts of modified silica for 30 min to obtain component A; reacting 50 parts of polyether polyol (PPG-2000), 15 parts of isocyanate (MDI-50), 2 parts of 1,4-butanediol and 0.1 parts of catalyst (DABCO) at 75℃ for 2 h to obtain polyurethane prepolymer; cooling the polyurethane prepolymer to 40℃, adding component A, and stirring at high speed (1000r / min) for 10 min to obtain the adhesive, with the viscosity controlled at 6000-7000mPa·s.

[0016] Preferably, the preparation method of modified silica is as follows: 450 parts of anhydrous ethanol and 20 parts of deionized water are mixed, the pH of the solution is adjusted to 4, and then 5-8 parts of KH-560 silane coupling agent (CAS: 2530-83-8) are added. The mixture is stirred at room temperature for 45 min to obtain a hydrolysate. 95-105 parts of fumed silica are slowly added to the hydrolysate in 3 batches and ultrasonically treated for 20-40 min to obtain a dispersion slurry. The dispersion slurry is heated to 75℃ and refluxed and condensed, and stirred at a constant temperature for 3-4 h. Most of the ethanol is removed by rotary evaporator, and after washing and filtration, the mixture is vacuum dried at 110℃ for 4 h to obtain modified silica.

[0017] Preferably, the preparation method of the rigid noise-reducing rock wool board for ships is as follows: one side of the PET film of the protective layer is subjected to plasma treatment with a discharge power of 1.2kW, a discharge gap of 2mm, a treatment speed of 15m / min, and an air treatment atmosphere to obtain a pretreated protective layer; using a double-roller glue coater, adhesive is applied to both sides of the rock wool core layer with a single-sided glue application amount of 200-250g / m²; then the pretreated protective layer is covered on both sides of the glued rock wool core layer and fed into a double-track continuous laminator with the first section at 80℃, the second section at 120℃, and the third section at 150℃, a surface pressure of 0.4-0.6MPa, and a traveling speed of 2.0-2.5m / min to obtain the rigid noise-reducing rock wool board for ships.

[0018] Another aspect of the present invention provides a rigid noise-reducing rock wool board for ships, which comprises a rock wool core layer, a protective layer and an adhesive.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention introduces amino-modified hollow glass microspheres into the rock wool core layer, combined with the vertical pleating structure of the fibers, to construct a composite mechanical system. The vertically oriented rock wool fibers provide the main compressive support, while the KH-550 modified hollow glass microspheres act as rigid nodes filling the fiber gaps. Their chemical bonding (crosslinking of amino and phenolic resins) prevents them from detaching under stress, significantly improving the overall stiffness of the board. Simultaneously, the hollow cavity structure inside the hollow glass microspheres causes multiple reflections and scattering of sound waves, extending the sound wave propagation path within the material and increasing sound energy dissipation. Therefore, while significantly improving structural strength, it does not sacrifice sound absorption performance but rather enhances the blocking efficiency for mid-to-low frequency noise.

[0021] The protective layer of this invention adopts a composite structure of rigid aluminum foil and PET film, the adhesive layer adopts an epoxy-polyurethane IPN system, and the core layer is high-density rock wool. Together, these three elements constitute a vibration reduction and noise reduction system. When sound waves or mechanical vibrations act on the board, the high-modulus protective layer forces the intermediate adhesive layer to undergo shear deformation. Because the adhesive is an interpenetrating network structure formed by flexible polyurethane and rigid epoxy resin, and is doped with nano-graphene sheets, this structure has an extremely wide damping temperature range and a high loss factor, which can convert a large amount of mechanical vibration energy into heat energy dissipation. This design is specifically designed to address the low-frequency structural sound transmission generated by ship engines, making up for the shortcomings of traditional rock wool, which cannot effectively block low-frequency noise by simply relying on porous sound absorption.

[0022] To address the shortcomings of PET film, such as low surface energy and difficulty in adhesion, this invention utilizes plasma technology to introduce polar groups such as -OH and -COOH onto the PET surface. Combined with the high reactivity of E-51 epoxy resin in the adhesive, a strong chemical bond (COC bond) is achieved between the organic protective layer and the inorganic rock wool matrix during the high-temperature curing stage (150℃). This chemical anchoring replaces traditional physical adsorption, significantly improving the peel strength of the interface. Even in the harsh environment of long-term high salt spray and high humidity on ships, the protective layer remains resistant to blistering and peeling, maintaining the structural integrity and long-term protective performance of the composite board.

[0023] This invention introduces KH-560 surface-functionalized epoxy nano-silica into the adhesive. On the one hand, during the coating stage, the modified silica imparts excellent thixotropic properties to the adhesive, solving the problem of excessive adhesive penetration leading to interface defects or sagging when applying adhesive to porous rock wool surfaces, thus ensuring the formation of a continuous and uniform damping layer. On the other hand, after curing, the modified silica and the nano-graphene sheets work synergistically to form a micro-reinforcing framework in the polymer matrix, preventing creep of the adhesive layer at high temperatures and further ensuring the dimensional stability of the board under extreme temperatures.

[0024] This invention employs a segmented temperature-controlled curing process (80℃ leveling - 120℃ polyurethane reaction - 150℃ epoxy crosslinking) to ensure the orderly formation of the IPN structure and the full progress of the interfacial chemical reaction. Simultaneously, although an organic adhesive layer and PET film are introduced, the high thermal conductivity of graphene rapidly dissipates localized hot spots. Combined with the flame-retardant properties of the outer aluminum foil and the non-combustible nature of the core rock wool, the overall panel still meets the stringent thermal insulation requirements of marine materials. Furthermore, the introduction of hydrogen-containing silicone oil in the core layer endows the material with excellent hydrophobicity, preventing the degradation of thermal and sound insulation performance caused by moisture absorption of the rock wool, fully meeting the usage requirements of ocean-going vessels in complex climatic environments. Attached Figure Description

[0025] Figure 1 The diagram shows the compressive strength and thermal conductivity of Example 1 and Comparative Examples 9-11 in this invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention provides a rigid noise-reducing rock wool board for ships and its preparation method. The technical solution is as follows:

[0028] Example 1: 200 parts anhydrous ethanol and 20 parts deionized water were added to a reaction vessel and stirred until homogeneous. Glacial acetic acid was added dropwise while stirring to adjust the pH of the solution to about 4.5. 1.8 parts KH-550 were added and the mixture was stirred at low speed at room temperature for 40 minutes to obtain a modified solution. 100 parts hollow glass microspheres were slowly added to the modified solution. The temperature was raised to 65°C, and the stirring speed was controlled below 100 r / min. The mixture was stirred at a constant temperature for 2 hours. After the reaction was completed, the slurry was filtered to obtain a microsphere filter cake. The filter cake was placed in a forced-air drying oven and dried at 80°C for 1 hour. Then the temperature was raised to 120°C and kept at that temperature for 2 hours. After natural cooling, the mixture was passed through a 60-mesh sieve to obtain modified glass microspheres.

[0029] 450 parts of anhydrous ethanol and 20 parts of deionized water were mixed, and the pH of the solution was adjusted to 4. Then, 6 parts of KH-560 silane coupling agent were added, and the mixture was stirred at room temperature for 45 min to obtain a hydrolysate. 100 parts of fumed silica were slowly added to the hydrolysate in 3 batches, and the mixture was ultrasonically treated for 30 min to obtain a dispersion slurry. The dispersion slurry was heated to 75℃ and refluxed and condensed, and the mixture was stirred at a constant temperature for 3.5 h. Most of the ethanol was removed by rotary evaporator, and the mixture was washed, filtered, and vacuum dried at 110℃ for 4 h to obtain modified silica.

[0030] 80 parts basalt and 20 parts diabase were mixed to obtain a basalt mixture. 9 parts water-soluble phenolic resin, 7 parts modified glass microspheres, 0.5 parts polymethylhydrosiloxane aqueous emulsion (solid content 35%), and 0.3 parts naphthenic oil emulsion were mixed and stirred to obtain a mixed emulsion. The basalt mixture was placed in a cupola furnace at a temperature of 1450℃, and a four-roll centrifuge was operated at a speed of 4800 r / min. The mixed emulsion was sprayed into the fiber stream through a high-pressure nozzle at the centrifugal roller spinning point. Subsequently, a pendulum was used for felting at a oscillation frequency of 55 times / min. A differential pleating machine was used to fold and compress the fiber layer, controlling the pleat ratio at 4:1. The mixture was then placed in a curing oven at a temperature of 190℃ for 20 minutes to obtain the rock wool core layer.

[0031] One side of a rigid aluminum foil is corona treated to achieve a dyne value greater than 38 dyne / cm, resulting in a pretreated aluminum foil. A polyurethane adhesive is then coated onto the treated surface of the pretreated aluminum foil at a coating weight of 3.5 g / m². 2 The coating is placed in an oven and dried by gradually increasing the temperature from 65°C to 85°C. Then, the coated surface is bonded to a PET film and hot-pressed. The temperature of the composite steel roller is 75°C and the composite pressure is 0.5MPa. Finally, it is cured at 50°C for 64 hours to obtain the protective layer.

[0032] Component A was obtained by mixing and dispersing 40 parts of E-51 bisphenol A epoxy resin, 4 parts of dicyandiamide, 0.3 parts of nano-graphene sheets and 0.1 parts of modified silica for 30 min; polyurethane prepolymer was obtained by reacting 50 parts of polyether polyol, 15 parts of isocyanate, 2 parts of 1,4-butanediol and 0.1 parts of catalyst (DABCO) at 75℃ for 2 h; polyurethane prepolymer was cooled to 40℃, component A was added, and the mixture was stirred at high speed (1000 r / min) for 10 min to obtain binder with a viscosity controlled at 6500 mPa·s.

[0033] One side of the PET film in the protective layer is subjected to plasma treatment with a discharge power of 1.2kW, a discharge gap of 2mm, a treatment speed of 15m / min, and an air treatment atmosphere to obtain a pretreated protective layer. Using a two-roller adhesive coater, adhesive is applied to both sides of the rock wool core layer with a single-sided adhesive application amount of 225g / m². The pretreated protective layer is then placed over both sides of the adhesive-coated rock wool core layer and fed into a dual-track continuous laminator. The first section is at 80℃, the second section at 120℃, and the third section at 150℃, with a surface pressure of 0.5MPa and a travel speed of 2.2m / min, to obtain a rigid noise-reducing rock wool board for marine applications.

[0034] Examples 2-5 refer to the parameter conditions in Example 1, with specific differences shown in Table 1.

[0035] Table 1 Parameters and conditions for Examples 1-5

[0036] Example Dosage / parts of water-soluble phenolic resin Dosage / parts of modified glass microspheres Melting temperature / °C Centrifuge speed / r / min Pendulum swing frequency / times / min Dosage / part of hollow glass microspheres Reaction temperature / ℃ Example 1 9 7 1450 4800 55 100 65 Example 2 8 6 1400 4500 50 95 60 Example 3 8 8 1420 4600 52 98 62 Example 4 10 6 1480 4700 58 102 68 Example 5 10 8 1500 5000 60 105 70

[0037] Comparative Example 1 follows the same parameters and conditions as in Example 1, except that the hollow glass microspheres are not modified.

[0038] Comparative Example 2 follows the same parameters and conditions as in Example 1, except that modified glass microspheres are not added.

[0039] Comparative Example 3 follows the same parameters and conditions as in Example 1, except that no polymethylhydrosiloxane was added to the aqueous emulsion.

[0040] Comparative Example 4 follows the same parameters and conditions as in Example 1, except that water-soluble phenolic resin is not added.

[0041] Experiment Example 1: Compressive Strength and Noise Reduction Performance Test

[0042] The compressive strength of Examples 1-5 and Comparative Examples 1-4 was tested according to standard GB / T 13480-2014; the noise reduction coefficient of Examples 1-5 and Comparative Examples 1-4 was tested according to standard GB / T 20247-2006. The results are shown in Table 2.

[0043] Table 2. Compressive strength and noise reduction performance tests of Examples 1-5 and Comparative Examples 1-4

[0044] Example Compressive strength / kPa Noise Reduction Factor / NRC Example 1 158 0.81 Example 2 151 0.75 Example 3 153 0.76 Example 4 156 0.78 Example 5 155 0.80 Comparative Example 1 112 0.78 Comparative Example 2 83 0.71 Comparative Example 3 150 0.80 Comparative Example 4 46 0.83

[0045] As can be seen from Table 2, the compressive strength of Comparative Example 1 decreased significantly compared with Example 1, and the noise reduction coefficient was slightly reduced. This is because the surface of the unmodified hollow glass microspheres is chemically inert with low surface energy, making it impossible to form an effective chemical bond with the phenolic resin matrix. In terms of microstructure, the bonding force between the unmodified microspheres and the resin interface is weak. When the rock wool board is subjected to vertical compressive load, the microspheres are prone to peel off from the resin matrix or slip, resulting in stress concentration and premature failure, and failing to play the supporting role of the rigid node. In addition, the microcracks generated by the interface peeling to a certain extent disrupt the continuous damping channel of sound wave propagation, resulting in a slight impairment of noise reduction performance. The compressive strength of Comparative Example 2 showed a precipitous drop, and the noise reduction coefficient also decreased significantly, which fully demonstrates the importance of the modified glass microspheres in this invention. In the absence of hollow glass microspheres, the compressive performance of the rock wool board relies solely on the hardness and vertical arrangement of the fibers. However, basalt fiber is inherently a brittle material, lacking compressive stiffness and unable to meet the hardness standards required for shipbuilding plates. Simultaneously, the absence of the hollow cavity structure within the microspheres significantly weakens the material's ability to reflect, scatter, and resonate with sound waves (especially mid-to-low frequency sound waves), resulting in a decline in overall sound absorption performance. The compressive strength of Comparative Example 3 decreased slightly compared to Example 1, but the decrease was not significant, and the noise reduction coefficient remained essentially the same. Although the main function of polymethylhydrosiloxane (containing hydrosilicone oil) is to impart hydrophobicity (waterproofing) to the rock wool board, it also plays a certain role in lubrication and auxiliary dispersion when participating in the mixing and blowing process in emulsion form. The data from Comparative Example 4 show that the sample has essentially lost its value as a rigid board. The water-soluble phenolic resin acts as "glue" between the rock wool fibers. Without the addition of resin, the fibers are only physically entangled and connected, resulting in an extremely loose structure that cannot maintain the three-dimensional shape of the board and collapses under pressure. Due to its extremely loose structure, it has a strong ability to absorb airborne sound, but this is a high sound absorption at the cost of sacrificing all mechanical properties. This, in turn, verifies that the proposed solution can still maintain excellent sound absorption performance while ensuring high bonding strength.

[0046] Examples 6-9 refer to the parameter conditions in Example 1, with specific differences shown in Table 3.

[0047] Table 3 Parameter conditions for Examples 1 and 6-9

[0048] Example <![CDATA[Coating amount of polyurethane adhesive / g / m 2 > Temperature of hot pressing composite / °C Dosage of epoxy resin (parts) Amount / parts of nano-graphene sheets Viscosity of adhesive / mPa·s Example 1 3.5 75 40 0.3 6500 Example 6 3 70 38 0.1 6000 Example 7 4 72 39 0.2 6200 Example 8 3 78 41 0.4 6800 Example 9 4 80 42 0.5 7000

[0049] Comparative Example 3 follows the same parameters and conditions as in Example 1, except that no polymethylhydrosiloxane was added to the aqueous emulsion.

[0050] Comparative Example 5 follows the same parameters and conditions as in Example 1, except that one side of the rigid aluminum foil is not subjected to corona treatment.

[0051] Comparative Example 6 follows the same parameters and conditions as in Example 1, except that no curing treatment is performed after hot-pressing the PET film.

[0052] Comparative Example 7 follows the same parameters and conditions as in Example 1, except that no nano-graphene sheets are added to the adhesive.

[0053] Comparative Example 8 follows the same parameters and conditions as in Example 1, except that the PET film side of the protective layer is not subjected to plasma treatment when the rock wool board is finally prepared.

[0054] Experimental Example 2: Tensile Strength, Noise Reduction Performance, and Hydrophobicity Tests

[0055] The tensile strength of Examples 1, 6-9, Comparative Example 3, and Comparative Example 5-8 was tested according to standard GB / T 30804-2014; the noise reduction performance was tested according to the method of Experimental Example 1; and the hydrophobicity of Examples 1, 6-9, Comparative Example 3, and Comparative Example 5-8 was tested according to standard GB / T 10299-2011. The results are shown in Table 4.

[0056] Table 4. Tensile strength, noise reduction performance, and hydrophobicity tests of Examples 1, 6-9, Comparative Examples 3, and Comparative Examples 5-8

[0057] Example Tensile strength / kPa Noise Reduction Factor / NRC Hydrophobicity / % Example 1 132 0.81 99.9 Example 6 126 0.77 99.3 Example 7 128 0.79 99.5 Example 8 130 0.80 99.6 Example 9 129 0.80 99.8 Comparative Example 3 125 0.80 52.3 Comparative Example 5 62 0.81 99.9 Comparative Example 6 81 0.80 99.8 Comparative Example 7 106 0.76 99.8 Comparative Example 8 48 0.65 99.9

[0058] Table 4 shows that Comparative Example 3 did not differ significantly from Example 1 in tensile strength and noise reduction coefficient, indicating that the hydrophobic agent itself does not perform the main mechanical bonding function. However, its hydrophobicity data showed a serious decrease. This is because without the addition of polymethylhydrosiloxane, the surface of the rock wool fiber lacks low surface energy methyl groups and cannot form a cross-linked hydrophobic network at high temperatures through Si-H bonds. Basalt fiber is essentially a hydrophilic inorganic silicate. Once it loses the protection of the hydrophobic agent, it is very easy to adsorb moisture through capillary action. In the high humidity environment of a ship, this material will quickly absorb moisture and fail, not only losing its thermal insulation performance, but also causing internal mold growth and a sharp increase in weight due to the presence of water. Comparative Example 5 showed a significant decrease in tensile strength. This example omitted the corona treatment step for the aluminum foil. During the rolling process, rigid aluminum foil often retains trace amounts of rolling oil on its surface, and the naturally formed oxide layer on the aluminum surface has low surface energy and high inertia. Without corona impact activation, the polyurethane adhesive cannot effectively wet and anchor the aluminum foil surface. In the vertical pull-out test, the aluminum foil layer and the PET layer are prone to interfacial delamination. Comparative Example 6 omitted the 50°C curing step after hot-pressing. Although it passed through hot-pressing rollers on the production line, the chemical cross-linking reaction between the main component and the curing agent (isocyanate) of the two-component polyurethane adhesive is a slow process, requiring time and temperature (curing) to complete the chain extension of molecular chains and the formation of the network structure. Without curing, the cohesive force within the adhesive layer is extremely low, and the chemical bonding with the substrate is incomplete. Under stress, the failure mainly occurs within the adhesive layer or at the adhesive interface, resulting in severely insufficient interlayer bonding strength of the composite board. Comparative Example 7 showed reduced tensile strength and noise reduction coefficient. The absence of graphene nanosheets caused the IPN adhesive to lose its microscopic mechanical interlocking and skeletal reinforcement effects, resulting in reduced modulus and strength of the adhesive layer and weakened connection between the rock wool core and protective layer. More importantly, graphene sheets construct a highly efficient frictional energy dissipation network in the adhesive; the lack of graphene reduces the damping loss factor of the adhesive layer, weakening the overall structural constraint damping effect and significantly lowering the noise reduction coefficient. Comparative Example 8, with its untreated PET film surface being chemically inert and lacking active groups such as -OH and -COOH, could not form ring-opening chemical bonds with the epoxy groups in the adhesive. Therefore, only a very weak physical adsorption force (van der Waals force) existed between the protective layer and the rock wool core. In the pull-out test, the protective layer almost instantly and completely debonded from the core, causing the entire component to lose its load-bearing capacity. Simultaneously, because the skin and core layers could not form a tight coupled vibration, the constraint damping mechanism completely failed, allowing sound waves to easily penetrate the panel, resulting in reduced noise reduction performance.

[0059] Examples 10-13 refer to the parameter conditions in Example 1, with specific differences shown in Table 5.

[0060] Table 5 Parameter conditions for Examples 1 and 10-13

[0061] Example Dosage of KH-560 / serving Amount / part of fumed silica Ultrasonic treatment time / min Stirring reaction time / h Adhesive application rate per side / g / m² Surface pressure / MPa Travel speed / m / min Example 1 6 100 30 3.5 225 0.5 2.2 Example 10 5 95 20 3 200 0.4 2.0 Example 11 7 98 25 3 210 0.6 2.1 Example 12 8 102 35 4 240 0.4 2.4 Example 13 6 105 40 4 250 0.6 2.5

[0062] Comparative Example 9 follows the same parameters and conditions as in Example 1, except that no modification treatment is applied to the fumed silica.

[0063] Comparative Example 10 follows the same parameters and conditions as in Example 1, except that no modified silica is added.

[0064] Comparative Example 11 follows the same parameters and conditions as in Example 1, except that it does not undergo a segmented curing process and is directly hot-pressed at 150°C.

[0065] Experiment Example 3: Compressive Strength and Thermal Insulation Performance Test

[0066] The compressive strength was tested according to the method in Experimental Example 1. The thermal conductivity of the rock wool board was determined using the steady-state plate method. The rock wool board was placed in an instrument for measuring thermal conductivity to obtain the thermal conductivity. The temperature control accuracy was ±0.1℃ for the hot plate and ±0.1℃ for the cold plate. The instrument's measurement accuracy was ±3%. The thermal conductivity measurement range was 0.01~1.6W / (m·K). The measurement time was 5 hours. Each sample was tested three times, and the average value was taken. The results are shown in Table 6. The compressive strength and thermal conductivity of Example 1 and Comparative Examples 9-11 are as follows: Figure 1 As shown.

[0067] Table 6. Compressive strength and thermal insulation performance tests of Examples 1, 10-13 and Comparative Examples 9-11

[0068] Example Compressive strength / kPa Thermal conductivity / W / (m·K) Example 1 158 0.033 Example 10 153 0.038 Example 11 155 0.036 Example 12 156 0.035 Example 13 156 0.036 Comparative Example 9 138 0.042 Comparative Example 10 95 0.040 Comparative Example 11 122 0.039

[0069] From Table 6 and Figure 1It can be observed that the compressive strength of Comparative Example 9 decreased to 138 kPa, while the thermal conductivity increased to 0.042 W / (m·K). This is because the surface of the unmodified KH-560 fumed silica contains a large number of hydrophilic hydroxyl groups, which have poor compatibility with the organic resin matrix and are prone to agglomeration. The agglomerated silica particles not only fail to play a reinforcing role in the microstructure, but also become stress concentration points in the adhesive layer, leading to a decrease in compressive strength. More seriously, the hydrophilicity of unmodified silica makes the adhesive layer easy to absorb moisture from the air. Since the thermal conductivity of water is much higher than that of air and resin, the moisture-absorbing adhesive layer becomes a thermal bridge, significantly increasing the overall thermal conductivity of the rock wool board and destroying its thermal insulation performance. Comparative Example 10 showed the most severe performance degradation, with compressive strength dropping to 95 kPa and thermal conductivity deteriorating to 0.040 W / (m·K). This reveals the core value of modified silica as a thixotropic agent. Without the addition of modified silica, the adhesive has low viscosity and lacks thixotropy (i.e., it is not thick when at rest but becomes thinner under stress). During the coating process, the flowing adhesive cannot remain on the surface of the porous rock wool, but instead excessively penetrates into the rock wool core layer due to gravity and capillary action. The lack of adhesive on the surface leads to poor adhesion between the protective layer and the core layer, and the interface cannot transfer load under pressure. The adhesive penetrates into the interior of the rock wool, filling the fiber gaps that should store still air. Since the thermal conductivity of the cured resin is much higher than that of still air, this resin impregnation phenomenon leads to a decrease in the thermal insulation capacity of the rock wool board. The compressive strength of Comparative Example 11 decreased to 122 kPa, while the thermal conductivity increased slightly. The adhesive of this invention is an interpenetrating network (IPN) structure formed by polyurethane (PU) and epoxy resin. The reaction kinetics of the two resins are different. Segmented curing allows the PU phase to grow in an orderly manner first, followed by the epoxy phase cross-linking and interpenetrating in the network to form a dense structure with low internal stress. Direct high temperature will cause the two reactions to occur explosively and simultaneously, resulting in uncontrolled reaction rates. The molecular chains freeze before they can unfold and arrange themselves, leading to an increase in defects inside the polymer network, uneven cross-linking density, and high internal stress, thereby reducing the macroscopic mechanical strength. At the same time, the excessively fast reaction leads to microbubbles or loose interfacial bonding, slightly increasing the heat conduction path.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing rigid noise-reducing rock wool boards for ships, characterized in that, Includes the following steps: Basalt mixture is melted and centrifuged into fibers. Modified glass microspheres are premixed with phenolic resin solution and sprayed into the fibers. After collection, pleating, and curing, a rock wool core layer is obtained. One side of rigid aluminum foil is corona treated and hot-pressed with PET film to obtain a protective layer. Epoxy resin, nano-graphene sheets, and modified silica are added to polyurethane prepolymer to obtain an adhesive. The adhesive is coated on both sides of the rock wool core layer and the protective layer is attached. After segmented curing, the rock wool board is obtained. The modified glass microspheres were obtained by modifying hollow glass microspheres with KH-550. The modified silica was obtained by modifying fumed silica with KH-560. The preparation method of the rock wool core layer is as follows: basalt and diabase are mixed to obtain the basalt mixture; water-soluble phenolic resin, the modified glass microspheres, a water emulsion of polymethylhydrosiloxane, and a naphthenic oil emulsion are mixed and stirred to obtain a mixed emulsion; the basalt mixture is melted, centrifuged into fibers, and the mixed emulsion is sprayed into the fiber stream, followed by pendulum-laid felting, pleating, and curing to obtain the rock wool core layer; the preparation method of the modified glass microspheres is as follows: anhydrous ethanol and deionized water are stirred evenly, the pH is adjusted to acidic, KH-550 is added, and stirred to obtain a modified liquid; The hollow glass microspheres are added to the modified liquid, stirred and reacted, and the slurry is filtered, dried and sieved to obtain the modified glass microspheres. The method for preparing the rock wool board is as follows: plasma treatment is performed on one side of the PET film of the protective layer to obtain a pretreated protective layer; the adhesive is coated on both sides of the rock wool core layer, the pretreated protective layer is covered on both sides of the coated rock wool core layer, and the rock wool board is obtained after three-stage hot pressing.

2. The method for preparing a rigid noise-reducing rock wool board for ships according to claim 1, characterized in that, The protective layer is prepared by: corona treatment on one side of the rigid aluminum foil to obtain a pretreated aluminum foil, coating the treated surface with polyurethane adhesive, drying it, and then hot-pressing the coated surface with the PET film to obtain the protective layer after curing.

3. The method for preparing a rigid noise-reducing rock wool board for ships according to claim 1, characterized in that, The adhesive is prepared by mixing and dispersing the epoxy resin, micronized dicyandiamide, the nano-graphene sheets and the modified silica to obtain component A; reacting polyether polyol, isocyanate, 1,4-butanediol and catalyst to obtain the polyurethane prepolymer; adding component A to the polyurethane prepolymer and stirring to obtain the adhesive.

4. The method for preparing a rigid noise-reducing rock wool board for ships according to claim 1, characterized in that, The modified silica is prepared by mixing anhydrous ethanol and deionized water, adjusting the pH to acidic, adding KH-560, and stirring to obtain a hydrolysate; adding the fumed silica to the hydrolysate, and ultrasonically treating to obtain a dispersion slurry; refluxing and condensing the dispersion slurry, and stirring to react; and filtering, washing, and vacuum drying to obtain the modified silica.

5. A rigid noise-reducing rock wool board for ships, characterized in that, The rock wool board comprises a rock wool core layer, a protective layer, and an adhesive; the rock wool board is prepared by the preparation method according to any one of claims 1-4.

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