High strength, deformation resistant paper faced gypsum board and method of making same

Abstract

The present application relates to the technical field of paper faced gypsum board, and particularly relates to high-strength anti-deformation paper faced gypsum board and a preparation method thereof, which comprises two layers of modified fireproof cover paper and a gypsum board core material and phase change energy storage capsules between the two layers of modified fireproof cover paper; the gypsum board core material is composed of a core slurry, and raw materials of the core slurry include, in terms of mass fraction, gypsum powder, modified starch, citric acid, water reducing agent, glass fiber, polypropylene fiber, graphite powder, vitrified microbead and foaming agent. The present application simultaneously adds glass fiber and polypropylene fiber in the core slurry, and the synergistic effect of the glass fiber and the polypropylene fiber can inhibit the expansion of micro-cracks caused by drying shrinkage and damp swelling, the glass fiber provides high modulus and tensile capacity, the polypropylene fiber enhances impact resistance and crack toughness, effectively compensates for the brittleness defect of the gypsum matrix, and the modified starch cooperates with the water reducing agent to optimize the flowability and compactness of the slurry, so that the overall strength of the core is structurally improved.

Description

Technical Field

[0001] This invention relates to the field of paper-faced gypsum board technology, specifically to high-strength, deformation-resistant paper-faced gypsum board and its preparation method. Background Technology

[0002] Paper-faced gypsum board is a lightweight building material made of building gypsum as the base material and covered with facing paper on both sides. With its lightweight, fire resistance, sound insulation, smooth surface and easy decoration, it is widely used in non-load-bearing interior partitions and ceilings in buildings. It can also be used as a base material for secondary processed products. With the rapid development of the construction industry and the in-depth promotion of green and environmental protection concepts, paper-faced gypsum board continues to occupy an important position in the construction market due to its excellent environmental performance, good sound and heat insulation effect and outstanding fire resistance.

[0003] Gypsum board is prone to warping and deformation when exposed to moisture or temperature changes. Especially in high humidity environments, the core of the board absorbs water and expands unevenly, resulting in an uneven surface that affects the decorative effect and service life. To address the problems mentioned above, this invention proposes a high-strength, deformation-resistant paper-faced gypsum board and its preparation method. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a high-strength, deformation-resistant paper-faced gypsum board and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: High-strength, deformation-resistant paper-faced gypsum board, comprising two layers of modified fire-retardant facing paper, a gypsum board core material between the two layers of modified fire-retardant facing paper, and a phase change energy storage capsule; The gypsum board core material is composed of a core slurry, and the raw materials of the core slurry include, by weight parts: 1000 parts gypsum powder, 10-20 parts modified starch (hydroxypropyl starch ether), 2-4 parts citric acid, 3-5 parts water-reducing agent (methyl allyl polyoxyethylene ether), 8-15 parts glass fiber, 5-10 parts polypropylene fiber, 15-25 parts graphite powder, 20-30 parts vitrified microspheres, and 1.5-2.5 parts foaming agent (sodium dodecyl sulfate); The phase change energy storage capsule is prepared through the following steps: S101. Melt paraffin wax and silica powder are stirred and mixed at 70-80℃, and then cooled to obtain a shaped phase change material; S102. Disperse the shaped phase change material in a mixed solvent, then add melamine-formaldehyde mixed monomers, stir at 70-80℃ to carry out in-situ polymerization reaction, and filter to obtain composite particles after the reaction is completed. S103. Disperse the composite particles in an aqueous phase, adjust the pH to 8-9.5 with sodium hydroxide and heat to 50-55℃. After reacting for 30-40 minutes, add γ-methacryloyloxypropyltrimethoxysilane dropwise. After the addition is complete, stir the reaction for 2-3 hours. After the reaction is complete, cool to 35-40℃ and adjust the pH to neutral with dilute hydrochloric acid. After filtration, washing and drying, the phase change energy storage capsule is obtained.

[0006] Furthermore, the modified fire-retardant facing paper is prepared through the following steps: S1. Beat softwood pulp and hardwood pulp to 35-40°SR, mix evenly, then add micro-nano magnesium aluminum hydrotalcite suspension, stir for 15-20 min, then add polyacrylamide, aluminum sulfate, and AKD sizing agent (alkyl ketene dimer emulsion) in sequence, continue stirring for 20-25 min, adjust the pH to 6.5-7.0 with aluminum sulfate to obtain modified pulp; S2. The modified pulp is formed, rolled and vacuum dewatered to form a wet paper web. The wet paper web is then pressed to achieve a dryness of 45%-50%, and dried at 105-115℃ until the moisture content is ≤8%. S3. Lightly calender one side using a soft calendering machine, with the linear pressure set at 15-20 kN / m. After calendering, cut and roll according to the width of the gypsum board production line to obtain modified fireproof facing paper.

[0007] Furthermore, in step S1, the mass ratio of softwood pulp, hardwood pulp, micro / nano magnesium aluminum hydrotalcite suspension, polyacrylamide, aluminum sulfate, and AKD sizing agent is 60:40:(5-15):(0.3-0.8):(0.5-1):(0.8-1.2), wherein the micro / nano magnesium aluminum hydrotalcite suspension is composed of magnesium aluminum hydrotalcite powder mixed with water in a mass ratio of 1:(3-4).

[0008] Furthermore, the core slurry is prepared through the following steps: S201. Stir gypsum powder, modified starch, citric acid, water-reducing agent, glass fiber, polypropylene fiber, graphite powder, and vitrified microspheres for 5-10 minutes to obtain a dry mixture. Dilute the foaming agent with water to make a 30-40 times-sized pre-made foam. S202. Add the dry mixture to water and stir for 2-3 minutes to form a slurry. Add the pre-made foam to the slurry and stir for 30-50 seconds to disperse the foam evenly and obtain the core slurry.

[0009] Furthermore, in step S201, the mass ratio of foaming agent to water is 1:(30-50).

[0010] Furthermore, in step S202, the mass ratio of dry mix to water is 1:(0.6-0.8), and the mass ratio of slurry to pre-made foam is 1:(0.05-0.15).

[0011] Furthermore, in step S101, the mass ratio of melted paraffin wax to silica powder is 1:(0.2-0.5).

[0012] Furthermore, in step S102, the mass ratio of the shaping phase change material, the mixed solvent, and the melamine-formaldehyde mixed monomer is 1:(5-10):(0.8-1), wherein the mixed solvent is composed of CNF, citric acid, and deionized water in a mass ratio of 1:(0.1-0.3):(80-100), and the melamine-formaldehyde mixed monomer is composed of melamine and formaldehyde in a mass ratio of 1:(1.5-1.8).

[0013] Furthermore, in step S103, the mass ratio of the composite particles, the aqueous phase, and γ-methacryloyloxypropyltrimethoxysilane is 1:(5-10):(0.05-0.2), wherein the aqueous phase is composed of polyvinyl alcohol and deionized water in a mass ratio of 1:(15-20).

[0014] Furthermore, the preparation process of the high-strength, deformation-resistant paper-faced gypsum board includes the following steps: S301. Use a modified fire-retardant protective paper as the lower protective paper, with the rough side of the paper facing up. Spray the core slurry onto the lower protective paper, controlling the thickness to be 5-6mm. Smooth it with a scraper. Place the phase change energy storage capsules, which account for 10-20% of the total mass of the core slurry, on the surface of the first layer of slurry. Spray the core slurry again to make the total thickness reach 12-14mm. Then use a scraper to level it. S302. Another modified fireproof protective paper is used as the upper protective paper, with the rough side facing down, covering the surface of the core slurry. The excess slurry is squeezed out by the forming roller and the upper and lower protective papers are tightly bonded to the core material. After standing for 25-30 minutes to solidify, it is dried and trimmed to obtain a high-strength, deformation-resistant paper-faced gypsum board.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention incorporates both glass fiber and polypropylene fiber into the core slurry. The synergistic effect of the glass fiber and polypropylene fiber can suppress the propagation of microcracks caused by drying shrinkage and moisture expansion. The glass fiber provides high modulus and tensile strength, while the polypropylene fiber enhances impact resistance and crack toughness, effectively compensating for the brittleness of the gypsum matrix. Modified starch acts as a binder to enhance the bonding force between gypsum crystals. Combined with a water-reducing agent, the slurry's fluidity and density are optimized, resulting in a structural improvement in the overall strength of the core slurry. 2. This invention uses phase change energy storage capsules evenly placed inside the core of the gypsum board. The paraffin inside the capsules undergoes a solid-liquid phase change within the phase change temperature range. When the ambient temperature rises, it absorbs heat, and when the ambient temperature drops, it releases heat, giving the gypsum board a passive temperature regulation capability. The phase change energy storage capsules use silica as a shaped skeleton to prevent paraffin leakage. The outer melamine-formaldehyde resin shell is modified to enhance the bonding stability with the gypsum matrix, ensuring that the heat storage / heat release function does not decay during long-term cyclic use. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the preparation process of the high-strength, deformation-resistant paper-faced gypsum board in this invention; Figure 2 This is a schematic diagram of the preparation process of the core slurry in this invention; Figure 3 This is a schematic diagram of the preparation process of the phase change energy storage capsule in this invention; Figure 4 This is a schematic diagram of the preparation process of the modified fire-retardant facing paper in this invention. Detailed Implementation

[0017] 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figures 1-4 The present invention provides a technical solution: Example 1: High-strength, anti-deformation paper-faced gypsum board includes two layers of modified fire-retardant facing paper, a gypsum board core material between the two layers of modified fire-retardant facing paper, and a phase change energy storage capsule. The gypsum board core material is composed of core slurry, the raw materials of which consist of the following components: 1000g gypsum powder, 10g modified starch, 2g citric acid, 3g water-reducing agent, 8g glass fiber, 5g polypropylene fiber, 15g graphite powder, 20g vitrified microspheres, and 1.5g foaming agent.

[0019] Preparation method of high-strength, deformation-resistant paper-faced gypsum board: I. Preparation of modified fire-retardant facing paper: S1. Beat 60g of softwood pulp and 40g of hardwood pulp to 35°SR, add 5g of magnesium aluminum hydrotalcite suspension (composed of magnesium aluminum hydrotalcite powder and water in a 1:3 ratio) and stir for 15min; add 0.3g of polyacrylamide, 0.5g of aluminum sulfate and 0.8g of AKD sizing agent and stir for 20min. Adjust the pH to 6.5 with aluminum sulfate to obtain the modified pulp. S2. The modified pulp is fed into a fourdrinier paper machine for forming. After rolling and vacuum dewatering, a wet paper web is formed. The wet paper web is then pressed, rolled, and vacuum dewatered to a dryness of 45%, and dried at 105℃ to a moisture content of ≤8%. S3. The paper is lightly calendered on one side using a soft calendering machine with a linear pressure of 15kN / m. After calendering, it is cut and rolled according to the width of the gypsum board production line to obtain a modified fireproof protective paper with a smooth side and a rough side.

[0020] II. Preparation of Phase Change Energy Storage Capsules: S101. Take 10g of melted paraffin wax and 2g of silicon dioxide, stir and mix them at 70℃, and cool to obtain a shaped phase change material; S102. Disperse 10g of shaped phase change material in 50g of mixed solvent (composed of CNF (CNF with a diameter of 10nm, selected as cellulose nanofibers, used to assist in dispersing the shaped phase change material and adjust the rheology of the slurry), citric acid, and deionized water in a 1:0.1:80 ratio), add 8g of melamine-formaldehyde mixed monomer (composed of melamine and formaldehyde in a 1:1.5 ratio), and polymerize in situ at 70℃ to obtain composite particles; S103. Disperse 10g of composite particles in 50g of aqueous phase (composed of polyvinyl alcohol and deionized water in a 1:15 ratio), adjust the pH to 8 with sodium hydroxide, heat to 50℃ and react for 30min, add 0.5g of γ-methacryloyloxypropyltrimethoxysilane dropwise and react for 2h, cool to 35℃, adjust the pH to neutral with dilute hydrochloric acid, filter, wash and dry.

[0021] III. Preparation of core slurry: S201. Dry mix the raw materials of the core slurry for 5 minutes; dilute the foaming agent with water at a ratio of 1:30 to prepare 30 times the amount of pre-made foam. S202. Take 1000g of dry mixture and add 600g of water and stir for 2 minutes to form a slurry. Add 50g of pre-made foam to every 1000g of slurry and stir for 30 seconds.

[0022] IV. Plasterboard Forming: S301. With the bottom protective paper facing upwards, spray slurry to a thickness of 5mm and smooth it out. Lay out phase change energy storage capsules accounting for 10% of the total mass of the core material, and then spray slurry to a total thickness of 12mm and level it out. S302, with the top protective paper facing down, pressurize with forming rollers, let stand for 25 minutes to solidify, and dry and trim to obtain high-strength, deformation-resistant paper-faced gypsum board.

[0023] Example 2: High-strength, anti-deformation paper-faced gypsum board includes two layers of modified fire-retardant facing paper, a gypsum board core material between the two layers of modified fire-retardant facing paper, and a phase change energy storage capsule. The gypsum board core material is composed of core slurry, the raw materials of which consist of the following components: 1000g gypsum powder, 15g modified starch, 3g citric acid, 4g water-reducing agent, 11g glass fiber, 8g polypropylene fiber, 20g graphite powder, 25g vitrified microspheres, and 2g foaming agent.

[0024] Preparation method of high-strength, deformation-resistant paper-faced gypsum board: I. Preparation of modified fire-retardant facing paper: S1. Beat 60g of softwood pulp and 40g of hardwood pulp to 38°SR, add 10g of magnesium aluminum hydrotalcite suspension (composed of magnesium aluminum hydrotalcite powder and water in a 1:3.5 ratio) and stir for 18min; add 0.6g of polyacrylamide, 0.8g of aluminum sulfate and 1g of AKD sizing agent and stir for 23min. Adjust the pH to 6.8 with aluminum sulfate to obtain the modified pulp. S2. The modified pulp is fed into a fourdrinier paper machine for forming. After rolling and vacuum dewatering, a wet paper web is formed. The wet paper web is then pressed, rolled, and vacuum dewatered to a dryness of 48%, and dried at 110℃ to a moisture content of ≤8%. S3. Lightly calender the paper using a soft calendering machine with a linear pressure of 18kN / m. After calendering, cut and roll the paper according to the width of the gypsum board production line to obtain the modified fireproof facing paper.

[0025] II. Preparation of Phase Change Energy Storage Capsules: S101. Take 10g of melted paraffin and 3.5g of silica, stir and mix at 75℃, and cool to obtain a shaped phase change material; S102. Disperse 10g of shaped phase change material in 80g of mixed solvent (composed of CNF (CNF with a diameter of 10nm, selected as cellulose nanofibers, used to assist in dispersing the shaped phase change material and adjust the rheology of the slurry), citric acid, and deionized water in a ratio of 1:0.2:90), add 9g of melamine-formaldehyde mixed monomer (composed of melamine and formaldehyde in a ratio of 1:1.6), and polymerize in situ at 75℃ to obtain composite particles; S103. Disperse 10g of composite particles in 80g of aqueous phase (composed of polyvinyl alcohol and deionized water in a 1:17 ratio), adjust the pH to 9 with sodium hydroxide, heat to 53℃ and react for 35min, add 1.3g of γ-methacryloyloxypropyltrimethoxysilane and react for 2.5h, cool to 38℃, adjust the pH to neutral with dilute hydrochloric acid, filter, wash and dry.

[0026] III. Preparation of core slurry: S201. Dry mix the raw materials of the core slurry for 8 minutes; dilute the foaming agent with water at a ratio of 1:40 to prepare 40 times the amount of pre-made foam. S202. Take 1000g of dry mixture and add 700g of water and stir for 2 minutes to form a slurry. Add 100g of pre-made foam to every 1000g of slurry and stir for 40 seconds.

[0027] IV. Plasterboard Forming: S301. With the bottom protective paper facing upward, spray slurry to 5.5mm and smooth it out. Lay the phase change energy storage capsule, which accounts for 15% of the total mass of the core material, and then spray slurry to a total thickness of 13mm and level it out. S302, with the top protective paper facing down, pressurize with forming rollers, let stand for 28 minutes to solidify, and dry and trim to obtain high-strength, deformation-resistant paper-faced gypsum board.

[0028] Example 3: High-strength, anti-deformation paper-faced gypsum board includes two layers of modified fire-retardant facing paper, a gypsum board core material between the two layers of modified fire-retardant facing paper, and a phase change energy storage capsule. The gypsum board core material is composed of core slurry, the raw materials of which are composed of the following components: 1000g gypsum powder, 20g modified starch, 4g citric acid, 5g water-reducing agent, 15g glass fiber, 10g polypropylene fiber, 25g graphite powder, 30g vitrified microspheres, and 2.5g foaming agent.

[0029] Preparation method of high-strength, deformation-resistant paper-faced gypsum board: I. Preparation of modified fire-retardant facing paper: S1. Beat 60g of softwood pulp and 40g of hardwood pulp to 40°SR, add 15g of magnesium aluminum hydrotalcite suspension (composed of magnesium aluminum hydrotalcite powder and water in a 1:4 ratio) and stir for 20min; add 0.8g of polyacrylamide, 1g of aluminum sulfate and 1.2g of AKD sizing agent and stir for 25min, adjust the pH to 7.0 with aluminum sulfate to obtain the modified pulp; S2. The modified pulp is fed into a fourdrinier paper machine for forming. After rolling and vacuum dewatering, a wet paper web is formed. The wet paper web is then pressed, rolled, and vacuum dewatered to a dryness of 50%, and dried at 115℃ to a moisture content of ≤8%. S3. Lightly calender the paper using a soft calendering machine with a linear pressure of 20kN / m. After calendering, cut and roll the paper according to the width of the gypsum board production line to obtain the modified fireproof facing paper.

[0030] II. Preparation of Phase Change Energy Storage Capsules: S101. Take 10g of melted paraffin wax and 5g of silica, stir and mix them at 80℃, and cool to obtain a shaped phase change material; S102. Disperse 10g of shaped phase change material in 100g of mixed solvent (composed of CNF (cellulose nanofibers with a diameter of 10nm, used to assist in dispersing the shaped phase change material and adjust the rheology of the slurry) in a ratio of 1:0.3:100, citric acid, and deionized water), add 10g of melamine-formaldehyde mixed monomer (composed of melamine and formaldehyde in a ratio of 1:1.8) and polymerize in situ at 80℃ to obtain composite particles; S103. Disperse 10g of composite particles in 100g of aqueous phase (composed of polyvinyl alcohol and deionized water in a 1:20 ratio), adjust the pH to 9.5 with sodium hydroxide, heat to 55℃ and react for 40min, add 2g of γ-methacryloyloxypropyltrimethoxysilane and react for 3h, cool to 40℃, adjust the pH to neutral with dilute hydrochloric acid, filter, wash and dry.

[0031] III. Preparation of core slurry: S201. Dry mix the raw materials of the core slurry for 10 minutes; dilute the foaming agent with water at a ratio of 1:50 to prepare 50 times the amount of pre-made foam. S202. Take 1000g of dry mixture and add 800g of water and stir for 3 minutes to form a slurry. Add 150g of pre-made foam to every 1000g of slurry and stir for 50 seconds.

[0032] IV. Plasterboard Forming: S301. With the bottom protective paper facing upward, spray slurry to 6mm and smooth it out. Lay the phase change energy storage capsule, which accounts for 20% of the total mass of the core material, and then spray slurry to a total thickness of 14mm and level it out. S302, with the top protective paper facing down, pressurize with forming rollers, let stand for 30 minutes to solidify, and dry and trim to obtain high-strength, deformation-resistant paper-faced gypsum board.

[0033] Comparative Example 1: Comparative Example 1, compared to Example 1, did not include a phase change energy storage capsule, but the remaining steps were exactly the same as in Example 1.

[0034] Comparative Example 2: Comparative Example 2 differs from Example 1 in that the modified fire-retardant facing paper is replaced with the facing paper base paper (Type A 890-F), and the remaining steps are exactly the same as in Example 1.

[0035] Comparative Example 3: Compared with Example 1, Comparative Example 3 replaced the core slurry with gypsum slurry (composed of gypsum clinker, water and additives), and the rest of the steps were exactly the same as in Example 1.

[0036] The high-strength, anti-deformation paper-faced gypsum boards prepared in Examples 1-3 and Comparative Examples 1-3 were cut into standard-sized specimens. At least 5 specimens were taken from each group for testing, and the average value of the results was taken. The specimens were cured for 24 hours at a temperature of (23±2)℃ and a relative humidity of (50±5)%.

[0037] I. Flexural strength (transverse / longitudinal) According to GB / T9775-2008, the specimen was cut into (400×300) mm pieces with a support span of 350 mm. The specimen was placed flat on the two supports of the flexural testing machine with the front facing up. A load was applied at a loading rate of (0.8±0.1) kN / s. The maximum load at which the specimen broke was recorded. The flexural strength in the transverse (perpendicular length direction) and longitudinal (parallel length direction) directions was tested respectively.

[0038] II. Moisture-induced deflection (resistance to deformation) Cut the specimen to size (300×300) mm according to Appendix B of GB / T9775-2008, and dry it to constant weight in an oven at (40±2)℃. Place the specimen face up on the deflection test bracket with the center distance between the two brackets 250 mm. Place an absorbent sponge on top of the specimen to cover the entire specimen. The sponge should be pre-soaked in water so that its mass is about 1.5 times the mass of the specimen. Keep the specimen at a humidity of (90±5)% and a temperature of (25±2)℃ for 2 hours. Remove the sponge and immediately measure the mid-span deflection value of the specimen with a dial indicator.

[0039] III. Fire stability (fire resistance) Cut the specimen to (300×50) mm according to GB / T9775-2008, dry it to constant weight in an oven at (40±2)℃, place the specimen horizontally above the flame of an alcohol torch at (800±20)℃ and a flame height of about 100 mm, and record the time (s) when continuous cracks or detachment appear on the back of the specimen.

[0040] IV. Phase Change Energy Storage Performance Specimens with dimensions of (300×300×plate thickness) mm were cut, thermocouples were pre-embedded in the geometric center of the specimens and fixed with thermally conductive adhesive, and cured in an environment of (23±2)℃ and RH (50±5)% for 24h. Based on Comparative Example 1 (without phase change capsules), the relative heat storage / heat release performance of Examples 1-3 and Comparative Examples 2-3 was calculated.

[0041] 1. Heat storage capacity test: The initial temperature is stabilized at 20℃. The temperature control chamber is heated to 50℃ (higher than the melting point of the phase change material) at a constant rate (e.g., 2℃ / min) and held for 60 min. The time (s) from the chamber temperature rising to 35℃ to the center temperature reaching 35℃ is recorded. Within the phase change range (e.g., 35-45℃), the rate of increase of the center temperature is lower than that of the blank control group. The total heat absorbed during the heating process is recorded.

[0042] 2. Heat release capacity test: After the heating is completed, turn off the heating and allow it to cool naturally or by forced cooling (set the temperature control chamber to cool down to 20℃ at a rate of 2℃ / min). Record the time (s) required for the center temperature to drop from 45℃ to 30℃. The specific test results are shown in Table 1. Table 1: Performance Test Table for High-Strength, Deformation-Resistant Paper-Faced Gypsum Board As can be seen from the data in Table 1, the high-strength, deformation-resistant gypsum board prepared in Examples 1-3 is significantly superior to that in Comparative Examples 1-3 in all aspects. In terms of mechanical properties, the flexural strength of the boards prepared in Examples 1-3 is significantly higher than that in the comparative examples. This is attributed to the synergistic reinforcing effect of glass fiber and polypropylene fiber in the core slurry, as well as the optimization of the slurry density by modified starch and water-reducing agent, which gives the gypsum board core material higher tensile strength and crack toughness, resulting in a substantial improvement in overall structural strength. Secondly, in terms of deformation resistance, the moisture-induced deflection of the boards prepared in Examples 1-3 is much smaller than that in the comparative examples. Ordinary gypsum board is prone to absorbing water and swelling, and warping in humid environments. However, this invention, by introducing a fiber network into the core and combining it with the waterproof barrier effect of modified fire-retardant facing paper, effectively inhibits the propagation of microcracks and non-uniform expansion, allowing the board to maintain good flatness even under high temperature and high humidity conditions. Regarding fire resistance, the fire stability of the gypsum board in the example is significantly better than that of the control sample prepared with ordinary facing paper core or conventional pulp. The modified fire-resistant facing paper contains micro-nano magnesium aluminum hydrotalcite, and the core also contains heat-resistant components such as graphite powder and vitrified microspheres, which together delay heat transfer and material damage under high flame temperature, giving the gypsum board a longer fire resistance time. In terms of phase change energy storage performance, the gypsum board in the example exhibits excellent heat storage and release capabilities. The phase change energy storage capsules uniformly distributed inside the core use paraffin as the phase change core and silica as the shaping skeleton, and are modified with melamine-formaldehyde resin shell, which can effectively absorb or release heat and achieve passive temperature regulation. In contrast, the board without phase change capsules in the control sample has almost no energy storage capacity, and although the control sample using ordinary facing paper or ordinary pulp has a certain heat storage effect, its overall performance is still inferior to that of the example.

[0043] 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 high-strength, deformation-resistant paper-faced gypsum board, characterized in that, It includes two layers of modified fire-retardant facing paper, a gypsum board core material between the two layers of modified fire-retardant facing paper, and a phase change energy storage capsule; The gypsum board core material is composed of a core slurry, which is formed by curing a slurry containing 1000 parts gypsum powder, 10-20 parts modified starch, 2-4 parts citric acid, 3-5 parts water-reducing agent, 8-15 parts glass fiber, 5-10 parts polypropylene fiber, 15-25 parts graphite powder, 20-30 parts vitrified microspheres and 1.5-2.5 parts foaming agent. The phase change energy storage capsule is prepared by the following method: Molten paraffin wax is mixed with silica powder to obtain a shaped phase change material with a porous framework. Then, it is polymerized in situ with melamine formaldehyde monomer to form a resin shell. Finally, the surface is modified with a silane coupling agent to obtain a phase change energy storage capsule. The modified fire-retardant facing paper is formed by molding, rolling, dewatering, and calendering a modified pulp containing softwood pulp, hardwood pulp, micro-nano magnesium aluminum hydrotalcite suspension, polyacrylamide, aluminum sulfate, and AKD sizing agent. The mass ratio of the softwood pulp, hardwood pulp, micro-nano magnesium aluminum hydrotalcite suspension, polyacrylamide, aluminum sulfate, and AKD sizing agent is 60:40:(5-15):(0.3-0.8):(0.5-1):(0.8-1.2). The micro-nano magnesium aluminum hydrotalcite suspension is composed of magnesium aluminum hydrotalcite powder mixed with water in a mass ratio of 1:(3-4).

2. The high-strength, deformation-resistant paper-faced gypsum board according to claim 1, characterized in that, The phase change energy storage capsule is prepared by the following steps: S101. Melt paraffin wax and silica powder are stirred and mixed at 70-80℃, and then cooled to obtain a shaped phase change material; S102. Disperse the shaped phase change material in a mixed solvent, then add melamine-formaldehyde mixed monomers, stir at 70-80℃ to carry out in-situ polymerization reaction, and filter to obtain composite particles after the reaction is completed. S103. Disperse the composite particles in an aqueous phase, adjust the pH to 8-9.5 with sodium hydroxide and heat to 50-55℃. After reacting for 30-40 minutes, add γ-methacryloyloxypropyltrimethoxysilane dropwise. After the addition is complete, stir the reaction for 2-3 hours. After the reaction is complete, cool to 35-40℃ and adjust the pH to neutral with dilute hydrochloric acid. After filtration, washing and drying, the phase change energy storage capsule is obtained.

3. The high-strength, deformation-resistant paper-faced gypsum board according to claim 1, characterized in that, The core slurry is prepared through the following steps: S201. Stir gypsum powder, modified starch, citric acid, water-reducing agent, glass fiber, polypropylene fiber, graphite powder, and vitrified microspheres for 5-10 minutes to obtain a dry mixture. Dilute the foaming agent with water to make a 30-40 times-sized pre-made foam. S202. Add the dry mixture to water and stir for 2-3 minutes to form a slurry. Add the pre-made foam to the slurry and stir for 30-50 seconds to disperse the foam evenly and obtain the core slurry.

4. The high-strength, deformation-resistant paper-faced gypsum board according to claim 1, characterized in that, The modified fire-retardant protective paper is prepared through the following steps: S1. Beat softwood pulp and hardwood pulp to 35-40°SR, mix evenly, then add micro-nano magnesium aluminum hydrotalcite suspension, stir for 15-20 min, add polyacrylamide, aluminum sulfate and AKD sizing agent in sequence, continue stirring for 20-25 min, adjust pH to 6.5-7.0 with aluminum sulfate to obtain modified pulp. S2. The modified pulp is formed, rolled and vacuum dewatered to form a wet paper web. The wet paper web is pressed to achieve a dryness of 45%-50%, and then dried at 105-115℃ until the moisture content is ≤8%. S3. Lightly calender one side using a soft calendering machine, with a linear pressure set to 15-20 kN / m. After calendering, cut and roll according to the width of the gypsum board production line to obtain modified fireproof facing paper.

5. The high-strength, deformation-resistant paper-faced gypsum board according to claim 3, characterized in that, In step S201, the mass ratio of foaming agent to water is 1:(30-50).

6. The high-strength, deformation-resistant paper-faced gypsum board according to claim 3, characterized in that, In step S202, the mass ratio of dry mix to water is 1:(0.6-0.8), and the mass ratio of slurry to pre-made foam is 1:(0.05-0.15).

7. The high-strength, deformation-resistant paper-faced gypsum board according to claim 2, characterized in that, In step S101, the mass ratio of melted paraffin wax to silica powder is 1:(0.2-0.5).

8. The high-strength, deformation-resistant paper-faced gypsum board according to claim 2, characterized in that, In step S102, the mass ratio of the shaping phase change material, the mixed solvent, and the melamine-formaldehyde mixed monomer is 1:(5-10):(0.8-1). The mixed solvent is composed of CNF, citric acid, and deionized water in a mass ratio of 1:(0.1-0.3):(80-100). The melamine-formaldehyde mixed monomer is composed of melamine and formaldehyde in a mass ratio of 1:(1.5-1.8).

9. The high-strength, deformation-resistant paper-faced gypsum board according to claim 2, characterized in that, In step S103, the mass ratio of composite particles, aqueous phase, and γ-methacryloyloxypropyltrimethoxysilane is 1:(5-10):(0.05-0.2), wherein the aqueous phase is composed of polyvinyl alcohol and deionized water in a mass ratio of 1:(15-20).

10. A method for preparing the high-strength, deformation-resistant paper-faced gypsum board according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: S301. Use a modified fire-retardant protective paper as the lower protective paper, with the rough side of the paper facing up. Spray the core slurry onto the lower protective paper, controlling the thickness to be 5-6mm. Smooth it with a scraper. Place the phase change energy storage capsules, which account for 10-20% of the total mass of the core slurry, on the surface of the first layer of slurry. Spray the core slurry again to make the total thickness reach 12-14mm. Then use a scraper to level it. S302. Another modified fireproof protective paper is used as the upper protective paper, with the rough side facing down, covering the surface of the core slurry. The excess slurry is squeezed out by the forming roller and the upper and lower protective papers are tightly bonded to the core material. After standing for 25-30 minutes to solidify, it is dried and trimmed to obtain a high-strength, deformation-resistant paper-faced gypsum board.

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