Thermal insulation rock wool board and preparation process thereof

Abstract

The invention belongs to the technical field of rock wool board preparation, and particularly relates to a thermal insulation rock wool board and a preparation process thereof, and the preparation process comprises the following steps: spraying a binder on rock wool fibers, and feeding the rock wool fibers into a wool collector to prepare a thin felt; the thin felts are stacked up and down, and a layer of phase change material is evenly laid between every two layers of thin felts; curing the thin felt on which the phase-change material is laid to obtain the rock wool board; the phase change material is prepared by the following steps: in a low-temperature and low-humidity environment, uniformly mixing calcium chloride hexahydrate powder, hydrophobic silicon dioxide powder and hydrogel powder to obtain mixed powder, filling pores of expanded graphite particles with the mixed powder, heating, and coating with a polyurethane film to obtain the phase change material. Moisture absorption and deliquescence behaviors of calcium chloride hexahydrate in a high-humidity environment can be effectively inhibited, the heat storage performance of the rock wool board in the high-humidity environment is improved, and then the indoor temperature adjusting capacity of the rock wool board is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of rock wool board preparation, and in particular relates to a thermal insulation rock wool board and a preparation process thereof. Background Art

[0002] Rockwool board is an inorganic thermal insulation material made primarily from natural minerals such as basalt. Its thermal conductivity is 0.035-0.045 W / (m·K). When applied to building exterior walls, it effectively inhibits heat conduction, reducing the rate of heat escaping from indoor spaces in winter and the rate of heat intrusion from outdoors in summer. However, rockwool has a specific heat capacity of 0.8-1.0 kJ / (kg·K), and its heat storage capacity is limited. While rockwool has a low thermal conductivity and can slow heat conduction, its low specific heat capacity and limited heat storage capacity mean that under sustained summer sunlight, a certain amount of heat will continue to enter the room through the rockwool board, causing the indoor temperature to gradually rise. To maintain a comfortable indoor environment, air conditioning systems must operate at high loads for extended periods of time, increasing energy consumption.

[0003] The Chinese invention patent application with publication number CN116856567A discloses a rock wool / calcium chloride hexahydrate-based insulation wall panel and a preparation method thereof. A compounded calcium chloride hexahydrate powder-based phase change material is used as an energy storage material, and a rock wool board is used as a carrier of the phase change energy storage material to prepare a thermal function-adjustable rock wool board. The energy storage and thermal insulation properties of the rock wool board are modified by coupling the rock wool board and the phase change material, thereby improving the heat storage capacity of the rock wool board. When the ambient temperature rises to the phase change temperature range of calcium chloride hexahydrate, the calcium chloride hexahydrate undergoes a solid-liquid phase change and absorbs a large amount of phase change latent heat, thereby reducing the temperature rise rate of the rock wool board, delaying the process of heat transfer to the interior of the wall, reducing the rate of indoor temperature rise, and reducing the operating load required for the air-conditioning system to maintain a comfortable indoor temperature, thereby achieving the purpose of energy saving and consumption reduction. However, calcium chloride hexahydrate powder has strong hygroscopic and deliquescent properties. When the external humidity is high and lasts for a long time, calcium chloride hexahydrate will absorb moisture from the outside and deliquesce, turning into a highly hydrated state or even a liquid form, and its original crystal structure will be destroyed. Since the phase change characteristics of calcium chloride hexahydrate depend on a stable crystal structure and hydration state, the phase change ability of calcium chloride hexahydrate in a high humidity environment for a long time is significantly weakened or even completely lost, and it cannot be used as a phase change material to give the rock wool board heat storage properties. The rock wool board has a weak ability to regulate indoor temperature. Summary of the Invention

[0004] The present invention provides a thermal insulation rock wool board and a preparation process thereof, which inhibits the moisture absorption and deliquescence behavior of calcium chloride hexahydrate in a high humidity environment, improves the heat storage performance of the rock wool board in a high humidity environment, and further enhances the rock wool board's ability to regulate indoor temperature.

[0005] In order to solve the above problems, the present invention provides the following technical solutions: A preparation process of a thermal insulation rock wool board comprises the following steps: S1. After spraying the binder on the rock wool fibers, the rock wool fibers are fed into a cotton collector to form a thin felt; S2. Lay thin felts on top of each other and evenly lay a layer of phase change material between every two layers of thin felts; S3, curing the thin felt on which the phase change material is laid to obtain a rock wool board; The phase change material is prepared by the following method: in a low-temperature and low-humidity environment, calcium chloride hexahydrate powder, hydrophobic silicon dioxide powder and hydrogel powder are mixed to obtain a mixed powder, the mixed powder is filled into the pores of expanded graphite particles, the temperature is increased, and a polyurethane film is coated to obtain the phase change material.

[0006] The present invention seals calcium chloride hexahydrate powder in expanded graphite particles through a polyurethane film, effectively blocking the contact and exchange of calcium chloride hexahydrate powder with moisture in the external environment. Even in a high humidity environment, the calcium chloride hexahydrate powder can maintain its original crystal structure and phase change properties, ensuring that the rock wool board can still have good heat storage capacity in a high humidity environment. When the external ambient temperature rises, the rate of increase in indoor temperature can be effectively slowed down.

[0007] In the present invention, a mixed powder is prepared under low temperature and low humidity conditions and the mixed powder is filled into the pores of expanded graphite. The low temperature condition causes water in the hydrogel powder to be in an ice crystal state, inhibits hydrogen bonding between molecules, and makes it difficult for the hydrogel powder to agglomerate, exhibiting good dispersibility, making it convenient for the hydrogel powder to be mixed with calcium chloride hexahydrate powder and hydrophobic silicon dioxide powder and smoothly filled into the pores of the expanded graphite. The low humidity condition can inhibit the calcium chloride hexahydrate from absorbing water from the external environment, thereby preventing the calcium chloride hexahydrate from deliquescence.

[0008] The filled expanded graphite particles are subjected to a heating treatment, free water ice crystals in the hydrogel powder melt, polymer chain segments stretch, and adjacent hydrogel powders can form a continuous three-dimensional network structure through hydrogen bonding or physical entanglement, stably encapsulating the calcium chloride hexahydrate powder therein, reducing the fluidity of the calcium chloride hexahydrate powder. In subsequent operations, the calcium chloride hexahydrate powder will not fall from the pores due to gravity or inertia, thereby increasing the filling amount of the calcium chloride hexahydrate. During the heating process, the hydrophobic silica powder is located between the calcium chloride hexahydrate powder and the hydrogel powder, acting as an isolation layer, reducing the probability of direct contact between the two, preventing the calcium chloride hexahydrate powder from absorbing a large amount of water from the hydrogel powder, reducing the loss of the calcium chloride hexahydrate powder, and increasing the amount of hydrogel powder with melted free water, which is conducive to the hydrogel powder constructing a continuous three-dimensional network structure.

[0009] During use of the present invention, when the temperature rises to the point where water inside the hydrogel is released and the air humidity around the calcium chloride hexahydrate increases, the water released from the hydrogel contacts a small portion of the calcium chloride hexahydrate, causing the crystal structure of this portion of the calcium chloride hexahydrate to change and reducing the phase change performance of this portion of the calcium chloride hexahydrate. However, the wrapping effect of the hydrogel can greatly increase the amount of calcium chloride hexahydrate remaining in the pores inside the expanded graphite, thereby improving the utilization rate of the pores inside the expanded graphite and enhancing the overall heat storage capacity of the rock wool board.

[0010] Furthermore, the preparation method of the calcium chloride hexahydrate is: dissolving anhydrous calcium chloride in water, cooling to 2°C under continuous stirring, precipitating calcium chloride hexahydrate crystals, filtering, drying, crushing, and sieving to obtain calcium chloride hexahydrate powder with an average particle size of 1-1.1 μm.

[0011] Furthermore, the hydrogel powder is prepared by the following method: adding acrylic acid, distilled water, azobisisobutyronitrile and methacrylamide to N-isopropylacrylamide, reacting at a temperature of 75°C for 3 hours, cooling, washing with deionized water, and then stirring and mixing with distilled water, calcium chloride and PAMAM dendritic polymer, reacting at a temperature of 75°C for 4 hours, washing with deionized water to obtain a hydrated gel, and then freeze-drying, crushing, and sieving to obtain a hydrogel powder with an average particle size of 50~55nm.

[0012] The present invention uses N-isopropylacrylamide, acrylic acid and methacrylamide as copolymers to form polymer chains through free radical copolymerization, thereby constituting the skeleton structure of the hydrated gel. Acrylic acid introduces carboxyl groups into the polymer chains, which undergo ionic crosslinking with calcium ions generated by the dissociation of calcium chloride, thereby restricting the free movement of polymer chain segments and enhancing the stability of the hydrated gel skeleton structure. After the hydrated gel is crushed, a hydrogel powder with a stable structure can be obtained.

[0013] Furthermore, the hydrated gel was freeze-dried in the following manner: the hydrated gel was divided into thin slices with a thickness of 1 cm, a single layer was laid flat and placed in a liquid nitrogen environment for 90 minutes, the gel was taken out and placed in a cold trap at -50°C, the vacuum degree was maintained at 25 Pa, the temperature was raised to -30°C and kept warm for 24 hours, the temperature was raised to -20°C and kept warm for 36 hours, and the temperature was raised to -5°C and kept warm for 7 hours to obtain a hydrated gel with a free water content of 3wt% to 5wt%.

[0014] The hydrated gel is freeze-dried using a multi-stage heating method, which allows the ice crystals to sublime slowly and evenly, avoiding the rapid sublimation of ice crystals caused by too fast a heating rate. The generated steam cannot be discharged quickly, which causes the hydrated gel to rupture. This protects the skeleton structure of the hydrated gel from being destroyed, which is conducive to obtaining a hydrogel powder with a complete structure.

[0015] Furthermore, the expanded graphite particles are prepared by the following method: expansive graphite is placed in an environment of 850° C. for 7 seconds, cooled, crushed, and sieved to obtain expanded graphite particles with an average particle size of 1.4 to 1.5 mm.

[0016] Furthermore, the average particle size of the hydrophobic silica powder is 50-55 nm.

[0017] Furthermore, in the mixed powder, the mass ratio of the hydrogel powder, the hydrophobic silicon dioxide powder and the calcium chloride hexahydrate powder is 1.1-1.2:6.0-6.1:192.0-192.1.

[0018] After the hydrogel powder, hydrophobic silica powder and calcium chloride hexahydrate powder are mixed with each other, the hydrogel powder is located in the gaps between adjacent calcium chloride powders, forming a three-dimensional network structure that penetrates the gaps. The hydrogel powders are interconnected by hydrogen bonding or physical entanglement, thereby stabilizing the morphology of the three-dimensional network structure. The calcium chloride hexahydrate powder is confined in the structure, and its fluidity is reduced. The addition of the hydrophobic silica powder reduces the direct contact area between the hydrogel powder and the calcium chloride hexahydrate powder, preventing the free water in the hydrogel from being absorbed in large quantities by the calcium chloride hexahydrate. While assisting in stabilizing the three-dimensional network structure, it also reduces the loss of the calcium chloride hexahydrate powder mass caused by water absorption and deliquescence.

[0019] Furthermore, the process of filling the mixed powder into the pores of the expanded graphite particles is as follows: in an environment of -5~-4°C and a relative humidity of 30%~32%, the mixed powder and expanded graphite particles are placed in a sealed container, the sealed container is vibrated at a frequency of 25~30 Hz and an amplitude of 1~1.2 mm, and the vacuum is evacuated to a vacuum degree of 8~10 kPa and maintained for 15~20 minutes, the mixed powder is filled into the pores of the expanded graphite, and the temperature is raised to 20~25°C and kept warm for 25~30 minutes.

[0020] The hydrogel powder, hydrophobic silica powder, and calcium chloride hexahydrate powder are mixed at -5 to -4°C and a relative humidity of 30% to 32%. At this humidity, the calcium chloride hexahydrate powder has a very low water absorption driving force and absorbs almost no water from the external environment in a short period of time. At this temperature, the water within the hydrogel powder is in the form of ice crystals, which inhibits intermolecular hydrogen bonding and prevents the hydrogel powder from agglomerating. This results in better dispersion, improved overall fluidity of the mixed powder, and facilitates its smooth filling into the pores of the expanded graphite particles. Under vacuum conditions, the air within the expanded graphite particles is extracted, creating a negative pressure environment that helps the mixed powder enter the pores of the expanded graphite particles more quickly and evenly. Vibration promotes the expulsion of gas from the expanded graphite particles, increasing the filling capacity of the mixed powder and the latent heat of phase change per unit volume of the phase change material.

[0021] Furthermore, the process of coating with polyurethane film is as follows: expanded graphite particles are placed in a fluidized bed coating machine, a nitrogen flow of 0.8 m / s is introduced from bottom to top, the inlet air temperature is 45°C, and the outlet air temperature is 35°C, water-based polyurethane is sprayed onto the outer surface of the expanded graphite particles through a nozzle, and the polyurethane film is coated on the outside of the expanded graphite particles to obtain a phase change material.

[0022] The nitrogen forms a uniform upward airflow, evenly blowing up and fully dispersing the expanded graphite particles. The surface of the expanded graphite particles is constantly renewed, which is conducive to the uniform deposition of water-based polyurethane droplets on their surface, forming a continuous and dense coating film. The nitrogen atmosphere can reduce the relative humidity around the expanded graphite particles and inhibit the moisture absorption behavior of the calcium chloride hexahydrate powder. The porous structure of the expanded graphite can act as a physical barrier in the early stage of coating, slowing the speed at which the nitrogen airflow directly contacts the hydrogel powder, preventing the hydrogel powder from dehydrating rapidly. Before the polyurethane film completely surrounds the expanded graphite particles, the stability of the three-dimensional network structure constructed by the hydrogel powder is maintained, preventing the calcium chloride hexahydrate powder from escaping from the pores of the expanded graphite.

[0023] A thermal insulation rock wool board is prepared using the above-mentioned thermal insulation rock wool board preparation process, comprising the following raw materials in parts by mass: 54-55 parts of rock wool fibers, 14-15 parts of phase change materials, and 1.1-1.2 parts of a binder; the binder is one or both of a phenolic resin and a urea-formaldehyde resin; the phase change material comprises the following materials in parts by mass: 63.4-63.5 parts of expanded graphite particles, 3.1-3.2 parts of hydrogel powder, 8.0-8.1 parts of hydrophobic silica powder, 192.0-192.1 parts of calcium chloride hexahydrate powder, and 134.6-134.7 parts of polyurethane.

[0024] The beneficial effects of the present invention are: The present invention uses a polyurethane film to water-proof and encapsulate calcium chloride hexahydrate powder in expanded graphite, effectively preventing the calcium chloride hexahydrate powder from absorbing external moisture and then deliquescing, so that the rock wool board still has good heat storage capacity in a high humidity environment.

[0025] The hydrogel powder, hydrophobic silica powder and calcium chloride hexahydrate powder are mixed under low temperature and low humidity conditions. The low temperature condition can make the free water in the hydrogel powder into an ice crystal state, thereby improving the overall fluidity of the mixed powder and facilitating the filling of the mixed powder into the pores of the expanded graphite particles. The low humidity condition can reduce the driving force of the calcium chloride hexahydrate powder to absorb water from the outside, thereby preventing the calcium chloride hexahydrate powder from deliquescence due to water absorption.

[0026] After the mixed powder is filled into the pores of the expanded graphite particles and heated, the free water ice crystals in the hydrogel powder melt, and adjacent hydrogel powders are cross-linked through hydrogen bonds or physical entanglement to form a continuous three-dimensional network structure, which confines the calcium chloride hexahydrate powder, reduces the fluidity of the calcium chloride hexahydrate powder, prevents the calcium chloride hexahydrate powder from escaping from the pores of the expanded graphite particles, and increases the phase change latent heat of the phase change material per unit volume; the hydrophobic silica powder is located between the hydrogel powder and the calcium chloride hexahydrate powder, preventing the calcium chloride hexahydrate powder from absorbing a large amount of free water from the hydrogel, thereby improving the stability of the three-dimensional network structure and reducing the quality loss caused by the deliquescence of the calcium chloride hexahydrate powder.

[0027] In the present invention, although part of the calcium chloride hexahydrate powder absorbs moisture in the hydrogel powder and deliquesces during the preparation and use of the phase change material, the three-dimensional network structure constructed between the hydrogel powders has a confining effect, which can effectively prevent the calcium chloride hexahydrate powder from escaping from the pores of the expanded graphite. Therefore, even if the calcium chloride hexahydrate powder partially deliquesces, a large amount of calcium chloride hexahydrate powder with normal phase change properties is still stably retained in the phase change material, thereby improving the overall heat storage capacity of the rock wool board. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the change of internal and external temperature of a room made of rock wool boards prepared in Example 6 and Comparative Examples 1 to 3 with the illumination time. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0030] Preparation Example 1 735g of anhydrous calcium chloride was added to 1000g of deionized water and stirred to dissolve at 25°C. The mixture was cooled to 2°C while stirring continuously to precipitate calcium chloride hexahydrate crystals. The crystals were filtered, dried, crushed, and sieved to obtain calcium chloride hexahydrate powder with an average particle size of 1μm. 100g of expandable graphite particles was placed in an electric expansion furnace at 850°C for 7 seconds, removed, naturally cooled, crushed, and sieved to obtain expanded graphite particles with an average particle size of 1.4mm. 113 g of N-isopropylacrylamide and 55 mL of acrylic acid were mixed, and 20 mL of distilled water, 0.2 g of azobisisobutyronitrile and 0.6 g of methacrylamide were added. The mixture was condensed and refluxed at 75°C for 3 h under nitrogen protection. After cooling to room temperature and washing with deionized water, 10 mL of distilled water, 10 g of calcium chloride hexahydrate powder and 15 g of PAMAM dendrimer were added. The mixture was condensed and refluxed at 75°C for 4 h under nitrogen protection and washed with deionized water. The mixture was then cut into 1 cm thick slices, laid flat in a single layer in a liquid nitrogen environment for 90 min, and then placed in a -50°C cold trap under a vacuum of 25 Pa. The temperature was increased to -30°C at a heating rate of 0.1°C / min and kept warm for 24 h, then to -20°C and kept warm for 36 h, and finally to -5°C and kept warm for 7 h. The mixture was crushed and sieved to obtain a hydrogel powder with an average particle size of 50 nm.

[0031] Under the conditions of -5°C and 30% relative humidity, 12.4 g of hydrogel powder, 32 g of hydrophobic silicon dioxide powder with a particle size of 50 nm, and 768 g of calcium chloride hexahydrate powder were put into a mixer and stirred thoroughly to obtain a mixed powder.

[0032] Preparation Example 2 735g of anhydrous calcium chloride was added to 1000g of deionized water and stirred to dissolve at 25°C. The mixture was cooled to 2°C while stirring continuously to precipitate calcium chloride hexahydrate crystals. The crystals were filtered, dried, crushed, and sieved to obtain calcium chloride hexahydrate powder with an average particle size of 1.1μm. 100g of expandable graphite particles was placed in an electric expansion furnace at 850°C for 7 seconds, removed, cooled naturally, crushed, and sieved to obtain expanded graphite particles with an average particle size of 1.5mm. 113 g of N-isopropylacrylamide and 55 mL of acrylic acid were mixed, and 20 mL of distilled water, 0.2 g of azobisisobutyronitrile and 0.6 g of methacrylamide were added. The mixture was refluxed at 75°C for 3 h under nitrogen protection, cooled to room temperature, washed with deionized water, and then 10 mL of distilled water, 10 g of calcium chloride hexahydrate powder and 15 g of PAMAM dendrimer were added. The mixture was refluxed at 75°C for 4 h under nitrogen protection, washed with deionized water, and then cut into 1 cm thick slices. A single layer was laid flat in a liquid nitrogen environment for 90 min, and then taken out and placed in a -50°C cold trap, maintaining a vacuum of 25 Pa. The temperature was increased to -30°C at a heating rate of 0.1°C / min and kept warm for 24 h, then increased to -20°C and kept warm for 36 h, and finally increased to -5°C and kept warm for 7 h. The mixture was crushed and sieved to obtain a hydrogel powder with an average particle size of 53 nm.

[0033] Under the conditions of -5°C and relative humidity of 31%, 12.6 g of hydrogel powder, 32.2 g of hydrophobic silicon dioxide powder with a particle size of 55 nm, and 768.2 g of calcium chloride hexahydrate powder were put into a mixer and stirred thoroughly to obtain a mixed powder.

[0034] Preparation Example 3 735g of anhydrous calcium chloride was added to 1000g of deionized water and dissolved by stirring at 25°C. The mixture was cooled to 2°C while stirring continuously to precipitate calcium chloride hexahydrate crystals. The crystals were filtered, dried, crushed, and sieved to obtain calcium chloride hexahydrate powder with an average particle size of 1.1μm. 100g of expandable graphite particles was placed in an electric expansion furnace at 850°C for 7 seconds, removed, cooled naturally, crushed, and sieved to obtain expanded graphite particles with an average particle size of 1.4mm. 113 g of N-isopropylacrylamide and 55 mL of acrylic acid were mixed, and 20 mL of distilled water, 0.2 g of azobisisobutyronitrile and 0.6 g of methacrylamide were added. The mixture was condensed and refluxed at 75°C for 3 h under nitrogen protection. After cooling to room temperature and washing with deionized water, 10 mL of distilled water, 10 g of calcium chloride hexahydrate powder and 15 g of PAMAM dendrimer were added. The mixture was condensed and refluxed at 75°C for 4 h under nitrogen protection and washed with deionized water. The mixture was then cut into 1 cm thick slices, laid flat in a single layer in a liquid nitrogen environment for 90 min, and then placed in a -50°C cold trap under a vacuum of 25 Pa. The temperature was increased to -30°C at a heating rate of 0.1°C / min and kept warm for 24 h, then to -20°C and kept warm for 36 h, and finally to -5°C and kept warm for 7 h. The mixture was crushed and sieved to obtain a hydrogel powder with an average particle size of 55 nm.

[0035] Under the conditions of -4°C and relative humidity of 32%, 12.8 g of hydrogel powder, 32.4 g of hydrophobic silicon dioxide powder with a particle size of 53 nm, and 768.4 g of calcium chloride hexahydrate powder were put into a mixer and stirred thoroughly to obtain a mixed powder.

[0036] Example 1 At -5°C and 30% relative humidity, 650g of the mixed powder and 63.4g of expanded graphite particles were placed in a sealed container and evacuated to a vacuum of 8kPa for 15 minutes. While the container was in the vacuum state, it was vibrated at a frequency of 25Hz and an amplitude of 1mm. The expanded graphite particles were removed, the excess powder was sieved out, and the container was placed in an environment of 25°C and 30% relative humidity for 25 minutes to obtain the filled expanded graphite particles. 617g of the filled expanded graphite particles were placed in an FPCG-300 fluidized bed coating machine. A nitrogen flow rate of 0.8m / s was introduced, with an inlet temperature of 45°C and an outlet temperature of 35°C. 324mL of the aqueous polyurethane Bayhydrol UH 2888 was sprayed through a nozzle in six injections, with a 3-minute interval between each injection. After the injections were completed, the fluidized state was maintained for 10 minutes before removal and cooling to room temperature to obtain a phase change material.

[0037] 74g of phenolic resin is evenly sprayed on every 3600g of rock wool fiber and then sent into a cotton collector to make a 120cm×60cm×1cm thin felt. 9 layers of thin felt are stacked up and down, and 116g of phase change material is evenly sprinkled between every two layers of thin felt. The rock wool board is obtained by heating and pressurizing the solidification process.

[0038] The mixed powder in this embodiment was prepared according to Preparation Example 1.

[0039] Example 2 At -5°C and 30% relative humidity, 650g of the mixed powder and 63.5g of expanded graphite particles were placed in a sealed container and evacuated to a vacuum of 8kPa for 15 minutes. While the container was in the vacuum state, it was vibrated at a frequency of 27Hz and an amplitude of 1.1mm. The expanded graphite particles were removed, the excess powder was sieved out, and the container was placed in an environment of 20°C and 31% relative humidity for 25 minutes to obtain the filled expanded graphite particles. 618g of the filled expanded graphite particles were placed in an FPCG-300 fluidized bed coating machine. A nitrogen flow rate of 0.8m / s was introduced, with an inlet temperature of 45°C and an outlet temperature of 35°C. 325mL of the aqueous polyurethane Bayhydrol UH 2888 was sprayed through a nozzle in six injections, with a 3-minute interval between each injection. After the injections were completed, the container was maintained in the fluidized state for 10 minutes before being removed and cooled to room temperature to obtain a phase change material.

[0040] 75g of phenolic resin is evenly sprayed on every 3615g of rock wool fiber and then sent into a cotton collector to make a 120cm×60cm×1cm thin felt. 9 layers of thin felt are stacked up and down, and 120g of phase change material is evenly sprinkled between every two layers of thin felt. The rock wool board is obtained by heating and pressurizing the solidification process.

[0041] The mixed powder in this embodiment was prepared according to Preparation Example 1.

[0042] Example 3 At -5°C and 31% relative humidity, 650g of the mixed powder and 63.4g of expanded graphite particles were placed in a sealed container and evacuated to a vacuum of 9kPa for 18 minutes. While the container was in the vacuum state, it was vibrated at a frequency of 27Hz and an amplitude of 1.2mm. The expanded graphite particles were removed, the excess powder was sieved out, and the container was placed in an environment of 25°C and 31% relative humidity for 28 minutes to obtain the filled expanded graphite particles. 618g of the filled expanded graphite particles were placed in an FPCG-300 fluidized bed coating machine. A nitrogen flow rate of 0.8m / s was introduced, with an inlet temperature of 45°C and an outlet temperature of 35°C. 324mL of the aqueous polyurethane Bayhydrol UH 2888 was sprayed through a nozzle in six applications, with a 3-minute interval between each spray. After spraying, the fluidized state was maintained for 10 minutes before removal and cooling to room temperature to obtain a phase change material.

[0043] 77g of phenolic resin is evenly sprayed on every 3650g of rock wool fiber and then sent into a cotton collector to make a 120cm×60cm×1cm thin felt. 9 layers of thin felt are stacked up and down, and 122g of phase change material is evenly sprinkled between every two layers of thin felt. The rock wool board is obtained by heating and pressurizing for curing.

[0044] The mixed powder in this embodiment was prepared according to Preparation Example 2.

[0045] Example 4 At -5°C and 31% relative humidity, 650g of the mixed powder and 63.5g of expanded graphite particles were placed in a sealed container and evacuated to a vacuum of 9kPa for 18 minutes. While the container was in the vacuum state, it was vibrated at a frequency of 29Hz and an amplitude of 1.1mm. The expanded graphite particles were removed, the excess powder was sieved out, and the container was placed in an environment of 20°C and 30% relative humidity for 28 minutes to obtain the filled expanded graphite particles. 617g of the filled expanded graphite particles were placed in an FPCG-300 fluidized bed coating machine. A nitrogen flow rate of 0.8m / s was introduced, with an inlet temperature of 45°C and an outlet temperature of 35°C. 326mL of the aqueous polyurethane Bayhydrol UH 2888 was sprayed through a nozzle in six injections, with a 3-minute interval between each injection. After the injections were completed, the container was maintained in the fluidized state for 10 minutes before being removed and cooled to room temperature to obtain a phase change material.

[0046] 74g of phenolic resin is evenly sprayed on every 3625g of rock wool fiber and then sent into a cotton collector to make a 120cm×60cm×1cm thin felt. 9 layers of thin felt are stacked up and down, and 120g of phase change material is evenly sprinkled between every two layers of thin felt. The rock wool board is obtained by heating and pressurizing the solidification process.

[0047] The mixed powder in this embodiment was prepared according to Preparation Example 2.

[0048] Example 5 At -4°C and 32% relative humidity, 650g of the mixed powder and 63.4g of expanded graphite particles were placed in a sealed container and evacuated to a vacuum of 10kPa for 20 minutes. While the container was in the vacuum state, it was vibrated at a frequency of 29Hz and an amplitude of 1.2mm. The expanded graphite particles were removed, excess powder was sieved out, and the container was placed in an environment of 23°C and 30% relative humidity for 30 minutes to obtain the filled expanded graphite particles. 570g of the filled expanded graphite particles were placed in an FPCG-300 fluidized bed coating machine. A nitrogen flow rate of 0.8m / s was introduced, with an inlet temperature of 45°C and an outlet temperature of 35°C. 325mL of the aqueous polyurethane Bayhydrol UH 2888 was sprayed through a nozzle in six injections, with a 3-minute interval between each injection. After the injections were completed, the container was maintained in the fluidized state for 10 minutes before being removed and cooled to room temperature to obtain a phase change material.

[0049] 78g of phenolic resin is evenly sprayed on every 3660g of rock wool fiber and then sent into a cotton collector to make a 120cm×60cm×1cm thin felt. 9 layers of thin felt are stacked up and down, and 124g of phase change material is evenly sprinkled between every two layers of thin felt. The rock wool board is obtained by heating and pressurizing the solidification process.

[0050] The mixed powder in this embodiment was prepared according to Preparation Example 3.

[0051] Example 6 At -4°C and 32% relative humidity, 650g of the mixed powder and 63.5g of expanded graphite particles were placed in a sealed container and evacuated to a vacuum of 10kPa for 20 minutes. While the container was in the vacuum state, it was vibrated at a frequency of 30Hz and an amplitude of 1.2mm. The expanded graphite particles were removed, the excess powder was sieved out, and the container was placed in an environment of 23°C and 32% relative humidity for 30 minutes to obtain the filled expanded graphite particles. 618g of the filled expanded graphite particles were placed in an FPCG-300 fluidized bed coating machine, and a nitrogen flow rate of 0.8m / s was introduced with an inlet air temperature of 45°C and an outlet air temperature of 35°C. 326mL of the aqueous polyurethane Bayhydrol UH 2888 was sprayed through a nozzle in six injections, with a 3-minute interval between each injection. After the injections were completed, the container was maintained in the fluidized state for 10 minutes before being removed and cooled to room temperature to obtain a phase change material.

[0052] 79g of phenolic resin is evenly sprayed on every 3665g of rock wool fiber and then sent into a cotton collector to make a 120cm×60cm×1cm thin felt. 9 layers of thin felt are stacked up and down, and 124g of phase change material is evenly sprinkled between every two layers of thin felt. The rock wool board is obtained by heating and pressurizing for curing.

[0053] The mixed powder in this embodiment was prepared according to Preparation Example 3.

[0054] The present invention also provides comparative examples and conducts relevant tests.

[0055] Comparative Example 1 The difference from Example 6 is that the filled expanded graphite particles are not coated with a polyurethane film, 105 g of expanded graphite particles are evenly sprinkled between every two layers of thin felt, and other components and preparation processes are the same as those of Example 6 to obtain a rock wool board.

[0056] Comparative Example 2 The difference from Example 6 is that no hydrogel is added during the preparation of the mixed powder, and the other components and preparation process are the same as those of Example 6 to obtain a rock wool board.

[0057] Comparative Example 3 Phase change energy storage material was prepared according to the preparation method described in the patent application document with publication number CN116856567A. 79g of phenolic resin was evenly sprayed on every 3665g of rock wool fiber and then sent into a cotton collector to make a thin felt of 120cm×60cm×1cm. 9 layers of thin felt were stacked up and down, and 97g of phase change energy storage material was evenly sprinkled between every two layers of thin felt. The rock wool board was obtained by heating and pressurizing for curing.

[0058] Temperature regulation ability test of rock wool board The temperature regulation ability of the rock wool board was tested by making a house. Nine groups of house samples were made using the rock wool boards prepared in Examples 1 to 6 and Comparative Examples 1 to 3. The internal space of the house was 60cm×120cm×60cm, consisting of a 60cm×120cm×5cm rock wool board and five EPS boards. The rock wool board was located at the top. Temperature sensors were set inside and outside the house to detect changes in the temperature inside and outside the house. A 300w heating light source was set 35cm above the rock wool board to simulate sunlight. The house was placed in an environment with a humidity of 75% and a temperature of 25°C for 72 hours to complete the pretreatment. Then the heating light source was turned on and the changes in the temperature inside and outside the house with the illumination time of each house were recorded, as shown in Table 1. Based on the experimental data of the house prepared with the rock wool boards prepared in Example 6 and Comparative Examples 1 to 3, a schematic diagram of the changes in the temperature inside and outside the house with the illumination time was drawn, as shown in Table 1. Figure 1 shown.

[0059] Table 1

[0060] According to Table 1 and Figure 1 Analysis shows that compared with Example 6, the rock wool board prepared in Comparative Example 1 shows a strong ability to suppress the temperature rise in the room before 1 hour of illumination. During the illumination period of 2 hours to 4 hours, the temperature in the room of Comparative Example 1 is higher than that of Example 6, especially after 2.2 hours, it is still higher than the temperature outside the room, indicating that the rock wool board in Comparative Example 1 mainly relies on the moisture absorbed by the hydrogel to regulate the indoor temperature, rather than relying on the phase change heat absorption of calcium chloride hexahydrate for regulation; Compared with the rock wool boards prepared in Comparative Example 3 and Example 6, the indoor temperature of Comparative Example 3 is not much different from the outdoor temperature, and the ability to suppress temperature rise is very poor, indicating that calcium chloride hexahydrate has been deliquesced and liquefied in a high humidity environment for a long time, and has almost lost its phase change heat storage capacity; The rock wool boards prepared in Examples 1 to 6 all showed a good ability to suppress the temperature rise inside the room within 4 hours of illumination, indicating that the polyurethane film wrapping can effectively inhibit calcium chloride hexahydrate from absorbing water from the external environment, and the high humidity environment has little effect on the performance of the phase change material. The rock wool board still has good heat storage capacity and strong temperature regulation ability in a high humidity environment.

[0061] Compared with Example 6, the temperature regulation ability of the rock wool board prepared in Comparative Example 2 is weaker, indicating that the presence of hydrogel can increase the filling amount of calcium chloride hexahydrate, increase the mass of calcium chloride hexahydrate per unit volume of rock wool board, and improve the temperature regulation ability of rock wool board.

[0062] Phase change material cycle stability test 20 g of each phase change material prepared in Examples 1 to 6 was taken and placed in a test tube, and a thermal resistor was inserted 1 cm away from the bottom of the test tube. The air humidity was maintained at 70%. The test tube was placed in a 50°C constant temperature water bath for 60 min, and then placed in a 10°C low temperature constant temperature bath for 60 min. After being taken out, each phase change material was subjected to DSC testing using a differential scanning calorimeter DSC1 manufactured by Mettler-Toledo, Switzerland, to obtain the phase change temperature, peak temperature and phase change latent heat of the phase change material after one cycle; then the test tube was repeatedly placed in an environment of 50°C and 10°C to obtain the phase change temperature, peak temperature and phase change latent heat of each phase change material after the 50th, 100th and 200th cycles, as shown in Table 2.

[0063] Table 2

[0064] According to Table 2, the phase change materials prepared in Examples 1 to 6 still exhibit good phase change performance after undergoing 200 phase change cycles in a high humidity environment. When the phase change materials are filled in the rock wool board, they can give the rock wool board a long-term and stable heat storage capacity.

[0065] The above is a preferred embodiment of the present invention. Those skilled in the art may make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A preparation process of thermal insulation rock wool board, characterized in that: The following steps are involved: S1. After spraying the binder on the rock wool fibers, the rock wool fibers are fed into a cotton collector to form a thin felt; S2. Lay thin felts on top of each other and evenly lay a layer of phase change material between every two layers of thin felts; S3, curing the thin felt on which the phase change material is laid to obtain a rock wool board; The phase change material is prepared by the following method: in a low-temperature and low-humidity environment, calcium chloride hexahydrate powder, hydrophobic silicon dioxide powder and hydrogel powder are mixed to obtain a mixed powder, the mixed powder is filled into the pores of expanded graphite particles, the temperature is increased, and a polyurethane film is coated to obtain the phase change material.

2. The preparation process of a thermal insulation rock wool board according to claim 1, characterized in that: The calcium chloride hexahydrate is prepared by dissolving anhydrous calcium chloride in water, cooling to 2° C. under continuous stirring, precipitating calcium chloride hexahydrate crystals, filtering, drying, crushing, and sieving to obtain calcium chloride hexahydrate powder with an average particle size of 1 to 1.1 μm.

3. The preparation process of a thermal insulation rock wool board according to claim 2, characterized in that: The hydrogel powder is prepared by the following method: adding acrylic acid, distilled water, azobisisobutyronitrile and methacrylamide to N-isopropylacrylamide, reacting at a temperature of 75°C for 3 hours, cooling, washing with deionized water, stirring and mixing with distilled water, calcium chloride and PAMAM dendritic polymer, reacting at a temperature of 75°C for 4 hours, washing with deionized water to obtain a hydrated gel, and then freeze-drying, crushing, and sieving to obtain a hydrogel powder with an average particle size of 50-55 nm.

4. The preparation process of a thermal insulation rock wool board according to claim 3, characterized in that: The hydrated gel is freeze-dried in the following manner: the hydrated gel is divided into thin slices with a thickness of 1 cm, a single layer is laid flat and placed in a liquid nitrogen environment for 90 minutes, the hydrated gel is taken out and placed in a cold trap at -50°C, the vacuum degree is maintained at 25 Pa, the temperature is raised to -30°C and kept warm for 24 hours, the temperature is raised to -20°C and kept warm for 36 hours, and the temperature is raised to -5°C and kept warm for 7 hours to obtain a hydrated gel with a free water content of 3wt% to 5wt%.

5. The preparation process of a thermal insulation rock wool board according to claim 4, characterized in that: The expanded graphite particles are prepared by the following method: placing expandable graphite in an environment of 850° C. for 7 seconds, cooling, crushing, and screening to obtain expanded graphite particles with an average particle size of 1.4 to 1.5 mm.

6. The process for preparing a thermal insulation rock wool board according to claim 5, characterized in that: The average particle size of the hydrophobic silica powder is 50-55 nm.

7. The process for preparing a thermal insulation rock wool board according to claim 6, characterized in that: In the mixed powder, the mass ratio of the hydrogel powder, the hydrophobic silicon dioxide powder and the calcium chloride hexahydrate powder is 1.1-1.2:6.0-6.1:192.0-192.

1.

8. The process for preparing a thermal insulation rock wool board according to claim 7, characterized in that: The process of filling the mixed powder into the pores of the expanded graphite particles is as follows: in an environment of -5 to -4°C and a relative humidity of 30% to 32%, the mixed powder and expanded graphite particles are placed in a sealed container, the sealed container is vibrated at a frequency of 25 to 30 Hz and an amplitude of 1 to 1.2 mm, and the vacuum is evacuated to a vacuum degree of 8 to 10 kPa and maintained for 15 to 20 minutes, the mixed powder is filled into the pores of the expanded graphite, and the temperature is raised to 20 to 25°C and kept warm for 25 to 30 minutes.

9. The process for preparing a thermal insulation rock wool board according to claim 8, characterized in that: The process of coating the polyurethane film in the preparation process of the phase change material is as follows: the expanded graphite particles filled with the mixed powder are placed in a fluidized bed coating machine, a nitrogen flow of 0.8 m / s is introduced from bottom to top, the inlet air temperature is 45°C, and the outlet air temperature is 35°C. Water-based polyurethane is sprayed onto the outer surface of the expanded graphite particles through a nozzle, and the polyurethane film is coated on the outside of the expanded graphite particles to obtain the phase change material.

10. A thermal insulation rock wool board, prepared by the thermal insulation rock wool board preparation process according to any one of claims 3 to 9, characterized in that: The invention comprises the following raw materials in parts by mass: 54-55 parts of rock wool fibers, 14-15 parts of phase change materials and 1.1-1.2 parts of binders; the binders are one or both of phenolic resin and urea-formaldehyde resin; the phase change materials comprise the following materials in parts by mass: 63.4-63.5 parts of expanded graphite particles, 3.1-3.2 parts of hydrogel powder, 8.0-8.1 parts of hydrophobic silica powder, 192.0-192.1 parts of calcium chloride hexahydrate powder and 134.6-134.7 parts of polyurethane.

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