Gypsum plaster board and preparation method thereof

Abstract

The invention discloses a gypsum plaster board and a preparation method thereof. The gypsum plaster board comprises a board core and surface protection paper, wherein the board core is prepared from the following raw materials: nano cellulose, gypsum clinker, a nano inorganic material, hydrogen-containing silicone oil, an emulsion, modified starch, a water reducing agent, a foaming agent and water; the preparation method of the gypsum plaster board comprises the following steps: adding a nano inorganic material, nano cellulose and a foaming agent into water, mixing and stirring to obtain first slurry; mixing gypsum clinker, hydrogen-containing silicone oil, an emulsion, modified starch, a water reducing agent and the first slurry, and performing ultrasonic treatment to obtain second slurry; pouring the second slurry between an upper layer of surface protection paper and a lower layer of surface protection paper, and carrying out lap joint, firm adhesion and molding to prepare a wet board; and after the wet board is solidified, drying, trimming, sealing and packaging to obtain the gypsum plaster board. The gypsum plaster board is good in water resistance, low in water absorption and surface water absorption and high in strength.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a water-resistant reinforced gypsum board and a preparation method thereof. Background Art

[0002] Gypsum board is made of building gypsum as the main raw material, with a small amount of additives and water mixed, then poured between the upper and lower layers of face paper, and then edge sealed, flattened and dried. It has been widely used in partition walls and ceilings of various buildings such as residences, office buildings and shopping malls.

[0003] However, due to the high solubility of gypsum and the many cracks and pores inside, ordinary paper-faced gypsum has problems such as poor water resistance. Currently, the core of the water-resistant paper-faced gypsum board on the market has a water-repellent added to it, and the face paper is also composed of water-resistant face paper, but the water resistance test results are not ideal, and the surface water absorption is prone to unqualified.

[0004] In the agricultural products and food processing industry, by-products generally account for 20% to 30% of the total mass of agricultural products, and some even account for more than 50%. Among them, the residual residues from fruit and vegetable processing are about 5 million tons per year. At present, the main way to high-value utilization of fruit and vegetable processing residues is to extract pectin, pigments and bioactive substances, but in the end, a large amount of extraction residues will still be produced and urgently need to be utilized. Summary of the invention

[0005] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of protection of this application.

[0006] The purpose of the present application is to provide a water-resistant reinforced gypsum board and a preparation method thereof. The gypsum board has good water resistance, low water absorption rate and surface water absorption, and high strength.

[0007] The first aspect of the present application provides a paper-faced gypsum board, the paper-faced gypsum board comprises a board core and a facing paper, the board core raw materials comprise: nanocellulose, gypsum clinker, nano inorganic material, hydrogen-containing silicone oil, emulsion, modified starch, water reducing agent, foaming agent and water; The preparation method of the paper-faced gypsum board comprises: adding nano inorganic material, nano cellulose and foaming agent into water, mixing and stirring to obtain a first slurry; mixing gypsum clinker, hydrogen-containing silicone oil, emulsion, modified starch, water reducing agent and the first slurry, and subjecting to ultrasonic treatment to obtain a second slurry; pouring the second slurry between two upper and lower layers of face paper, overlapping and bonding them to form a wet board; after the wet board is solidified, drying, trimming, sealing and packaging are performed to obtain the paper-faced gypsum board.

[0008] In an exemplary embodiment, the nanocellulose is nanocellulose made from fruit and vegetable processing residues.

[0009] In an exemplary embodiment, the fruit and vegetable processing residues are selected from one or more of sugarcane bagasse, apple pomace, and pineapple pomace.

[0010] In an exemplary embodiment, the size of the nanocellulose is 200-800 nm.

[0011] In an exemplary embodiment, the gypsum clinker is selected from any one or more of desulfurized gypsum clinker, natural gypsum clinker, phosphogypsum clinker and titanium gypsum clinker.

[0012] In an exemplary embodiment, the specific surface area of ​​the gypsum clinker is 300-400 m 2 / kg; wherein the specific surface area is the Blaine specific surface area.

[0013] In an exemplary embodiment, the particle size of the gypsum clinker is 30-150 μm.

[0014] In an exemplary embodiment, the nano inorganic material is selected from nano SiO 2 、α-phase nano-Al 2 O 3 、Nano-CaCO 3 , or one or more of nano-SiC.

[0015] In an exemplary embodiment, the size of the nano inorganic material is 30-400 nm.

[0016] In an exemplary embodiment, the emulsion is selected from one or more of polyvinyl acetate emulsion, vinyl acetate-ethylene copolymer emulsion, styrene-butadiene emulsion, and styrene-acrylic emulsion.

[0017] In an exemplary embodiment, the modified starch is one or both of modified corn starch and modified tapioca starch.

[0018] In an exemplary embodiment, the viscosity of the modified starch may be 1000-5000 mPa·s.

[0019] In an exemplary embodiment, the water reducer is one or more of a polycarboxylate water reducer or a naphthalene-based water reducer.

[0020] In an exemplary embodiment, the foaming agent is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and sodium fatty alcohol polyoxyethylene ether sulfate.

[0021] In an exemplary embodiment, the core material of the board includes, by weight: 100 parts by weight of gypsum clinker, 0.2-2 parts by weight of nano-inorganic material, 0.1-0.5 parts by weight of nano-cellulose, 0.3-0.5 parts by weight of hydrogen-containing silicone oil, 1-3 parts by weight of emulsion, 0.2-0.8 parts by weight of modified starch, 0.1-0.5 parts by weight of water reducer, 0.01-0.05 parts by weight of foaming agent, and 58-70 parts by weight of water.

[0022] In an exemplary embodiment, the core material of the board is composed, by weight, of: 100 parts by weight of gypsum clinker, 0.2-2 parts by weight of nano-inorganic material, 0.1-0.5 parts by weight of nano-cellulose, 0.3-0.5 parts by weight of hydrogen-containing silicone oil, 1-3 parts by weight of emulsion, 0.2-0.8 parts by weight of modified starch, 0.1-0.5 parts by weight of water reducer, 0.01-0.05 parts by weight of foaming agent, and 58-70 parts by weight of water.

[0023] In an exemplary embodiment, the content of the nano-inorganic material is, for example, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] In an exemplary embodiment, the content of the nanocellulose is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In an exemplary embodiment, the content of the hydrogen silicone oil is, for example, 0.3, 0.4, 0.5, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In an exemplary embodiment, the content of the emulsion is, for example, 1, 2, 3, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] In an exemplary embodiment, the content of the modified starch is, for example, 0.2, 0.4, 0.6, 0.8, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] In an exemplary embodiment, the content of the water reducing agent is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] In an exemplary embodiment, the content of the foaming agent is, for example, 0.01, 0.02, 0.03, 0.04, 0.05, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In an exemplary embodiment, the water content is, for example, 58, 60, 62, 64, 65, 66, 68, 70, etc. or a range value between any two of them as endpoint values, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] In an exemplary embodiment, the board core raw materials include the following components in parts by weight: 100 parts by weight of desulfurized gypsum, 0.2 parts by weight of nano-inorganic material, 0.1 parts by weight of nano-cellulose, 0.3 parts by weight of hydrogen-containing silicone oil, 1 part by weight of emulsion, 0.2 parts by weight of modified starch, 0.1 parts by weight of water reducer, 0.01 parts by weight of foaming agent, and 60 parts by weight of water.

[0032] In an exemplary embodiment, the core material of the board includes the following components, by weight: 100 parts by weight of natural gypsum, 1 part by weight of nano-inorganic material, 0.3 parts by weight of nano-cellulose, 0.5 parts by weight of hydrogen-containing silicone oil, 2 parts by weight of emulsion, 0.4 parts by weight of modified starch, 0.2 parts by weight of water reducer, 0.03 parts by weight of foaming agent, and 70 parts by weight of water.

[0033] In an exemplary embodiment, the board core raw materials include the following components in parts by weight: 100 parts by weight of phosphogypsum, 2 parts by weight of nano-inorganic material, 0.5 parts by weight of nano-cellulose, 0.5 parts by weight of hydrogen-containing silicone oil, 3 parts by weight of emulsion, 0.46 parts by weight of modified starch, 0.5 parts by weight of water reducer, 0.04 parts by weight of foaming agent, and 65 parts by weight of water.

[0034] The second aspect of the present application provides a method for preparing the above-mentioned gypsum board, the method for preparing the gypsum board comprising the following steps: 1) Adding nano inorganic material, nano cellulose and foaming agent into water and mixing and stirring to obtain a first slurry; 2) introducing gypsum clinker, hydrogen-containing silicone oil, emulsion, modified starch, water reducing agent and the first slurry into a mixer, mixing them, and subjecting them to ultrasonic treatment to obtain a second slurry; 3) pouring the second slurry between the upper and lower layers of face paper, overlapping and bonding them to form a wet board; 4) After the wet board solidifies, it enters a dryer for drying, and after drying, it is trimmed, sealed, and packaged to obtain the paper-faced gypsum board.

[0035] In an exemplary embodiment, the method for preparing the gypsum board further includes a step of preparing nanocellulose.

[0036] In an exemplary embodiment, the preparation of the nanocellulose comprises the following steps: a) washing the fruit and vegetable processing residue with water to remove impurities, drying and crushing to obtain fruit and vegetable processing residue powder; b) adding the fruit and vegetable processing residue powder into an acid solution for hydrolysis, and then adding pure water to stop the reaction; c) centrifuging the reaction solution obtained in step b), collecting the precipitate, and repeating the washing and centrifugation until the pH is neutral; d) drying the precipitate in step c) to obtain nanocellulose.

[0037] In an exemplary embodiment, in step a), the drying and crushing conditions are: drying and crushing at 40-60° C. and passing through a 80-120 mesh sieve; Optionally, the drying temperature is 45°C; Optionally, pass through an 80 mesh screen.

[0038] In an exemplary embodiment, step b) includes: adding the fruit and vegetable processing residue powder to an acid solution with a mass fraction of 40%-60% at a solid-liquid ratio of 1:10 to 1:20, and hydrolyzing in a water bath at 40-60° C. for 30-60 min. The “solid-liquid ratio” here refers to the ratio of the mass of the added solid material to the volume of the liquid.

[0039] In an exemplary embodiment, in step b), the acid solution is selected from any one of sulfuric acid, phosphoric acid, hydrochloric acid, oxalic acid, and phosphoric acid solution; preferably, it is a sulfuric acid solution.

[0040] In an exemplary embodiment, in step b), the solid-liquid ratio is 1:15.

[0041] In an exemplary embodiment, in step b), the mass fraction of the acid solution is 50%.

[0042] In an exemplary embodiment, in step b), the water bath temperature is 45° C. and the hydrolysis time is 40 min.

[0043] In an exemplary embodiment, in step c), the centrifugation condition is: centrifugation at 6000-8000 r / min for 15-20 min; Optionally, the rotation speed is 7000 r / min and the centrifugation time is 20 min.

[0044] In an exemplary embodiment, in step d), the drying temperature is 40-60°C; preferably, the drying temperature is 45°C.

[0045] In an exemplary embodiment, in step 2), the ultrasonic time is 20-60 s, and the ultrasonic frequency is 25-60 kHz.

[0046] In an exemplary embodiment, in step 2), the ultrasonic time is 40 s and the ultrasonic frequency is 50 kHz.

[0047] In an exemplary embodiment, in step 4), the temperature of the first zone of the dryer is 135-150° C., the temperature of the second zone is 120-130° C., the temperature of the third zone is 90-100° C., and the dryer speed is 55-70 m / min.

[0048] In an exemplary embodiment, in step 4), the speed of the dryer is 65 m / min.

[0049] The third aspect of the present application provides a gypsum board prepared by the above method.

[0050] The fourth aspect of the present application provides an application of nanocellulose made from fruit and vegetable processing residues in paper-faced gypsum board.

[0051] In an exemplary embodiment, the fruit and vegetable processing residues are selected from one or more of sugarcane bagasse, apple pomace, and pineapple pomace.

[0052] In an exemplary embodiment, the size of the nanocellulose is 200-800 nm.

[0053] Compared with the related technologies in the field, this application has the following technical effects: (1) The nanocellulose of the present application is a new type of bio-based functional material with good mechanical properties and high specific surface area. Its green, environmentally friendly and renewable characteristics promote the sustainable development of energy utilization; (2) The nano-inorganic materials are added in this application, which increases the strength of the gypsum board and improves the water resistance of the gypsum board; at the same time, nano-cellulose is conducive to the dispersion of nano-inorganic materials; (3) The present application preferentially mixes the nano-inorganic material and nano-cellulose with the foaming agent to reduce the agglomeration of the nano-inorganic material and nano-cellulose, so that the performance of the nano-inorganic material and nano-cellulose in the gypsum board can be more fully exerted; (4) Ultrasonic treatment further facilitates the dispersion of hydrogenated silicone oil, nano-inorganic materials and nano-cellulose; at the same time, it reduces the initial and final setting time of gypsum, which is beneficial to reduce the length of the molding belt and reduce the manufacturing cost; (5) The synergistic effect of nano-inorganic materials, nano-cellulose, emulsion and water reducer is beneficial to improving the strength of gypsum board.

[0054] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application will be described in detail below. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0056] The present invention is further described in detail below in conjunction with specific examples, but the examples should not be construed as limiting the present invention. The raw materials of this application are all conventional products on the market.

[0057] In the examples and comparative examples of the present application: Nano-SiO 2 purchased from Shanghai MacLean Biochemical Technology Co., Ltd., brand number S861577; Nano-SiC was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., brand number S817587; Nano calcium carbonate was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; brand number is C886288; α-phase nano-Al 2 O 3 purchased from Aladdin Biochemical Technology Co., Ltd., brand number A498369; Hydrogenated silicone oil was purchased from Wacker Chemical Industries, brand BS94; Styrene butadiene emulsion was purchased from Nanjing Stabile Trading Co., Ltd., brand number L8242; Polyvinyl acetate emulsion was purchased from Celanese Corporation, brand number 8482; Vinyl acetate-ethylene copolymer emulsion was purchased from Celanese Corporation, brand number 1378; The modified starch is modified corn starch purchased from Jinzhou Dongya Building Materials Co., Ltd., with a viscosity of 4300 mPa·s; The water reducer is a polycarboxylic acid water reducer purchased from Hubei Shanshufeng Building Materials Technology Co., Ltd., with the brand name SSF-4000; Naphthalene-based water reducer was purchased from Shenyang Xingzhenghe Chemical Co., Ltd., brand SNF-C; Sodium dodecylbenzene sulfonate foaming agent was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand S108366; Sodium dodecyl sulfate foaming agent was purchased from Jinan Yunfei Chemical Co., Ltd. with the brand name K12.

[0058] Example 1 The present embodiment provides a water-resistant reinforced gypsum board, which includes a board core and a facing paper. The board core raw materials, measured by weight, include the following components: 100 parts by weight of desulfurized gypsum, 0.2 parts by weight of nano-inorganic material, 0.1 parts by weight of nano-cellulose, 0.3 parts by weight of hydrogen-containing silicone oil, 1 part by weight of emulsion, 0.2 parts by weight of modified starch, 0.1 parts by weight of water reducer, 0.01 parts by weight of foaming agent, and 60 parts by weight of water.

[0059] The water-resistant reinforced gypsum board of this embodiment is prepared by the following method: 1) Preparation of nanocellulose: washing the fruit and vegetable processing residue with water to remove impurities, drying at 45°C, crushing and passing through an 80-mesh sieve to obtain fruit and vegetable processing residue powder; adding the fruit and vegetable processing residue powder to a 50% sulfuric acid solution at a solid-liquid ratio of 1:15, and hydrolyzing in a water bath at 45°C for 40 min; then adding pure water to terminate the reaction; centrifuging the reaction solution at 7000 r / min for 20 min, collecting the precipitate, and repeatedly washing and centrifuging until the pH is neutral; drying the precipitate at 45°C to obtain nanocellulose; 2) adding the nano inorganic material, nano cellulose and foaming agent into water and mixing and stirring to obtain a first slurry; 3) introducing gypsum clinker, hydrogenated silicone oil, emulsion, modified starch, water reducing agent and the first slurry into a mixer, and ultrasonicating for 40 seconds at a frequency of 50 kHz to obtain a second slurry; 4) Pour the second slurry between the upper and lower layers of face paper, overlap and bond them together to form a wet board; 5) After the wet board solidifies, it enters the dryer for drying to obtain a gypsum board, wherein the temperature of the first zone of the dryer is 135-150°C, the temperature of the second zone is 120-130°C, the temperature of the third zone is 90-100°C, and the dryer speed is 65m / min; the dried gypsum board is trimmed, sealed, and packaged to obtain a water-resistant reinforced paper-faced gypsum board.

[0060] Example 2 The present embodiment provides a water-resistant reinforced gypsum board, which includes a board core and a facing paper. The board core raw materials, measured by weight, include the following components: 100 parts by weight of natural gypsum, 1 part by weight of nano-inorganic material, 0.3 parts by weight of nano-cellulose, 0.5 parts by weight of hydrogen-containing silicone oil, 2 parts by weight of emulsion, 0.4 parts by weight of modified starch, 0.2 parts by weight of water reducer, 0.03 parts by weight of foaming agent, and 70 parts by weight of water.

[0061] The preparation method of the water-resistant reinforced gypsum board in this embodiment is the same as that in Embodiment 1.

[0062] Example 3 The present embodiment provides a water-resistant reinforced gypsum board, which includes a board core and a facing paper. The board core raw materials, measured by weight, include the following components: 100 parts by weight of phosphogypsum, 2 parts by weight of nano-inorganic material, 0.5 parts by weight of nano-cellulose, 0.5 parts by weight of hydrogen-containing silicone oil, 3 parts by weight of emulsion, 0.46 parts by weight of modified starch, 0.5 parts by weight of water reducer, 0.04 parts by weight of foaming agent, and 65 parts by weight of water.

[0063] The preparation method of the water-resistant reinforced gypsum board in this embodiment is the same as that in Embodiment 1.

[0064] Comparative Example 1 The difference between this comparative example and Example 1 is that no nano inorganic material is added to the paper-faced gypsum board. The remaining components and preparation method are the same as those in Example 1.

[0065] Comparative Example 2 The difference between this comparative example and Example 1 is that nanocellulose is not added to the paper-faced gypsum board. The remaining components and preparation method are the same as those in Example 1.

[0066] Comparative Example 3 The difference between this comparative example and Example 1 is that no emulsion is added to the gypsum board. The remaining components and preparation method are the same as those in Example 1.

[0067] Comparative Example 4 The difference between this comparative example and Example 1 is that no ultrasonic treatment is performed in the preparation method.

[0068] Comparative Example 5 The difference between this comparative example and Example 1 is that the first slurry is not prepared in advance in the preparation method, but the nano inorganic material, nano cellulose, foaming agent, gypsum clinker, hydrogen silicone oil, emulsion, modified starch, water reducing agent and water are put into the mixer together. The rest of the preparation method is the same as Example 1.

[0069] Performance Testing The properties of the 12 mm thick gypsum boards prepared in the above Examples 1-3 and Comparative Examples 1-5 were tested according to the method specified in the Chinese national standard GB / T 9775-2008. The test results are shown in Table 1 below.

[0070] Table 1 Implementation effect

[0071] The test results show that the water-resistant reinforced gypsum board provided in the present application has good water resistance, low water absorption rate and surface water absorption, and high strength.

[0072] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A gypsum board, characterized in that: The paper-faced gypsum board comprises a board core and a face paper, and the board core raw materials comprise: nano cellulose, gypsum clinker, nano inorganic material, hydrogen-containing silicone oil, emulsion, modified starch, water reducing agent, foaming agent and water; The preparation method of the paper-faced gypsum board comprises: adding nano inorganic material, nano cellulose and foaming agent into water, mixing and stirring to obtain a first slurry; mixing gypsum clinker, hydrogen silicone oil, emulsion, modified starch, water reducing agent and the first slurry, and subjecting to ultrasonic treatment to obtain a second slurry; pouring the second slurry between two upper and lower layers of face paper, overlapping and bonding them to form a wet board; after the wet board is solidified, drying, trimming, sealing and packaging are performed to obtain the paper-faced gypsum board.

2. The gypsum board according to claim 1, characterized in that: The board core raw materials include, by weight: 100 parts by weight of gypsum clinker, 0.2-2 parts by weight of nano inorganic material, 0.1-0.5 parts by weight of nano cellulose, 0.3-0.5 parts by weight of hydrogen-containing silicone oil, 1-3 parts by weight of emulsion, 0.2-0.8 parts by weight of modified starch, 0.1-0.5 parts by weight of water reducer, 0.01-0.05 parts by weight of foaming agent, and 58-70 parts by weight of water.

3. The gypsum board according to claim 1 or 2, characterized in that: The nanocellulose is nanocellulose made from fruit and vegetable processing residues; Optionally, the fruit and vegetable processing residue is selected from one or more of bagasse, apple residue, and pineapple residue; Optionally, the size of the nanocellulose is 200-800 nm.

4. The gypsum board according to claim 1 or 2, characterized in that: The gypsum clinker is selected from any one or more of desulfurized gypsum clinker, natural gypsum clinker, phosphogypsum clinker and titanium gypsum clinker; and / or The nano inorganic material is selected from one or more of nano SiO2, α-phase nano Al2O3, nano CaCO3, and nano SiC; and / or The emulsion is selected from one or more of polyvinyl acetate emulsion, vinyl acetate-ethylene copolymer emulsion, styrene-butadiene emulsion and styrene-acrylic emulsion; and / or The modified starch is selected from one or both of modified corn starch and modified cassava starch; and / or The water reducer is one or both of a polycarboxylate water reducer and a naphthalene water reducer; and / or The foaming agent is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and sodium polyoxyethylene fatty alcohol sulfate.

5. The gypsum board according to claim 4, characterized in that: The specific surface area of ​​the gypsum clinker is 300-400 m 2 / kg, with a particle size of 30-150 μm; and / or The size of the nano inorganic material is 30-400 nm; and / or The viscosity of the modified starch is 1000-5000 mPa·s.

6. A method for preparing a gypsum board according to any one of claims 1 to 5, characterized in that: The preparation method of the paper-faced gypsum board comprises the following steps: 1) Adding nano inorganic material, nano cellulose and foaming agent into water and mixing and stirring to obtain a first slurry; 2) introducing gypsum clinker, hydrogen-containing silicone oil, emulsion, modified starch, water reducing agent and the first slurry into a mixer, mixing them, and subjecting them to ultrasonic treatment to obtain a second slurry; 3) pouring the second slurry between the upper and lower layers of face paper, overlapping and bonding them to form a wet board; 4) After the wet board solidifies, it enters a dryer for drying, and after drying, it is trimmed, sealed, and packaged to obtain the paper-faced gypsum board.

7. The method according to claim 6, characterized in that The method for preparing the paper-faced gypsum board further comprises a step of preparing nanocellulose, and the preparation of the nanocellulose comprises: a) washing the fruit and vegetable processing residue with water to remove impurities, drying and crushing to obtain fruit and vegetable processing residue powder; b) adding the fruit and vegetable processing residue powder into an acid solution for hydrolysis, and then adding pure water to stop the reaction; c) centrifuging the reaction solution obtained in step b), collecting the precipitate, and repeating the washing and centrifugation until the pH is neutral; d) drying the precipitate in step c) to obtain nanocellulose.

8. The method according to claim 7, characterized in that In step a), the drying and crushing conditions are: drying and crushing at 40-60°C and passing through a 80-120 mesh sieve; Optionally, the drying temperature is 45°C; Optionally, pass through an 80 mesh screen.

9. The method according to claim 7, characterized in that: Step b) comprises: adding the fruit and vegetable processing residue powder to an acid solution with a mass fraction of 40%-60% at a solid-liquid ratio of 1:10 to 1:20, and hydrolyzing in a water bath at 40-60° C. for 30-60 min; Optionally, the solid-liquid ratio is 1:15; Optionally, the acid solution is selected from any one of sulfuric acid, phosphoric acid, hydrochloric acid, oxalic acid, and phosphoric acid solution; Optionally, the mass fraction of the acid solution is 50%; Optionally, the water bath temperature is 45°C and the hydrolysis time is 40 min.

10. The method according to claim 9, characterized in that The acid solution is a sulfuric acid solution.

11. The method according to claim 7, characterized in that In step c), the centrifugation condition is: centrifugation at 6000-8000 r / min for 15-20 min; Optionally, the rotation speed is 7000 r / min and the centrifugation time is 20 min.

12. The method according to claim 7, characterized in that In step d), the drying temperature is 40-60°C; Optionally, the drying temperature is 45°C.

13. The method according to any one of claims 6 to 12, characterized in that In step 2), the ultrasonic time is 20-60 seconds and the ultrasonic frequency is 25-60kHz; and / or In step 4), the temperature of the first zone of the dryer is 135-150°C, the temperature of the second zone is 120-130°C, the temperature of the third zone is 90-100°C, and the speed of the dryer is 55-70 m / min.

14. The method according to claim 13, characterized in that In step 2), the ultrasonic time is 40 seconds and the ultrasonic frequency is 50 kHz; and / or In step 4), the speed of the dryer is 65 m / min.

15. A gypsum board prepared by the method of any one of claims 6 to 14.

16. Application of nanocellulose made from fruit and vegetable processing residues in paper-faced gypsum board, wherein: The fruit and vegetable processing residue is selected from one or more of bagasse, apple residue, and pineapple residue; optionally, the size of the nanocellulose is 200-800 nm.

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