Fireproof smoke exhaust air pipe and preparation method thereof

Abstract

The invention discloses a fireproof smoke exhaust air pipe and a preparation method thereof, and belongs to the technical field of fire-fighting air pipes. The fireproof smoke exhaust air pipe comprises a plurality of pipe bodies connected in sequence, a first mounting plate and a second mounting plate are arranged at the two ends of each pipe body respectively, and the adjacent pipe bodies are connected through the first mounting plates and the second mounting plates; the pipe body comprises a fireproof plate, and the fireproof plate comprises a first gypsum layer, a rock wool layer and a second gypsum layer which are sequentially connected from inside to outside. The fire endurance of the fireproof smoke exhaust air pipe can be improved, compared with an existing fireproof smoke exhaust air pipe, the fireproof smoke exhaust air pipe is attractive, meanwhile, the floor height can be saved, and the situation that construction cannot be conducted due to the fact that the reserved height in the early stage is not enough is avoided.

Description

Technical Field

[0001] The present application relates to a fireproof smoke exhaust air duct and a preparation method thereof, belonging to the technical field of fire protection air ducts. Background Art

[0002] With the continuous improvement of people's living standards, super high-rise buildings and large commercial complexes have emerged one after another, which has put forward higher requirements for their safety. Fire-resistant smoke exhaust ducts are building smoke exhaust ducts made of various metal materials, and their exterior is usually covered with fireproof materials. Smoke exhaust ducts can not only improve indoor air quality, but also quickly exhaust smoke in the building in the event of a fire.

[0003] The fireproof materials used in existing fireproof smoke exhaust ducts are generally centrifugal glass wool, rock wool, fireproof fiber cotton coils, etc., but their fire resistance time is limited, and generally 1-2 hours is the limit; for example, when the fireproof material is centrifugal glass wool, the fire resistance time is about 75 minutes, when the fireproof material is rock wool, the fire resistance time is about 120 minutes, and when the fireproof material is fireproof fiber cotton coils, the fire resistance time is about 102 minutes; in addition, in order to ensure the fireproof performance of the duct, a large amount of fireproof material needs to be coated on the outside of the metal pipe, which is not only unsightly, but also when the reserved height in the design is not enough, the fireproof smoke exhaust duct cannot be installed at a later stage, thereby affecting the construction efficiency. Summary of the invention

[0004] In order to solve the above problems, a fireproof smoke exhaust duct and a preparation method thereof are provided, which can not only improve the fire resistance limit of the fireproof smoke exhaust duct, but also save floor height while being beautiful compared to the existing fireproof smoke exhaust duct, thereby avoiding the situation where construction cannot be carried out due to insufficient reserved height in the early stage.

[0005] The present invention provides the following technical solutions:

[0006] According to one aspect of the present application, a fireproof smoke exhaust duct is provided, comprising a plurality of pipe bodies connected in sequence, wherein a first mounting plate and a second mounting plate are respectively provided at both ends of the pipe body, and adjacent pipe bodies are connected by the first mounting plate and the second mounting plate;

[0007] The pipe body comprises a fireproof board, and the fireproof board comprises a first gypsum layer, a rock wool layer and a second gypsum layer which are sequentially connected from the inside to the outside.

[0008] Optionally, positioning grooves are provided on the four sides of the first mounting plate, and positioning protrusions are provided on the four sides of the second mounting plate, and the positioning grooves are snap-fitted with the positioning protrusions.

[0009] Optionally, the positioning groove includes a fitting groove and snap-fitting grooves relatively arranged on both sides of the fitting groove, and the positioning protrusion includes a fitting protrusion and snap-fitting protrusions relatively arranged on both sides of the fitting protrusion, the fitting groove fits with the fitting protrusion, and the snap-fitting groove snaps with the snap-fitting protrusion.

[0010] Optionally, the first mounting plate is provided with first through holes at four corners, the second mounting plate is provided with second through holes at four corners, and the fastening bolts pass through the first through holes and the second through holes in sequence and are connected with nuts to fix the first mounting plate and the second mounting plate.

[0011] Optionally, the thickness ratio of the first gypsum layer, the rock wool layer and the second gypsum layer is (1-3): (10-30): (1-3).

[0012] According to another aspect of the present application, a method for preparing a fireproof smoke exhaust duct is provided, comprising the following steps:

[0013] (1) adding polyvinyl alcohol emulsion, silicone waterproofing agent and water into a disperser, stirring at 3000-4000 r / min for 20-30 min, then adding gypsum powder, modified starch, wood fiber, dolomite powder, fly ash, composite flame retardant, calcium lignin sulfonate and vegetable protein retarder, and continuing stirring for 30-50 min to obtain gypsum slurry;

[0014] (2) pouring gypsum slurry on the inner and outer surfaces of the rock wool tape respectively, and covering each with a layer of glass fiber mesh cloth, so that the glass fiber mesh cloth is embedded in the gypsum slurry, and drying to obtain a semi-finished product;

[0015] (3) The semi-finished products obtained above are spliced ​​together to obtain a fireproof smoke exhaust duct.

[0016] Optionally, based on the weight of gypsum powder, the weight of the modified starch is 0.1-0.5%, the weight of wood fiber is 2-5%, the weight of dolomite powder is 3-6%, the weight of fly ash is 20-30%, the weight of the composite flame retardant is 10-15%, the weight of calcium lignin sulfonate is 0.3-0.8%, and the weight of the plant protein retarder is 0.05-0.1%;

[0017] Based on the weight of water, the weight of the polyvinyl alcohol emulsion is 2-4%, and the weight of the organosilicon waterproofing agent is 3-5%.

[0018] Optionally, the compound flame retardant is ammonium polyphosphate, pentaerythritol and melamine in a weight ratio of (1.5-3):(0.5-1.2):(0.5-1.2).

[0019] Optionally, the degree of polymerization of the ammonium polyphosphate is 1000-2000.

[0020] Optionally, the silane coupling agent is selected from at least one of KH-540, KH-550, and KH-792.

[0021] The beneficial effects of this application include but are not limited to:

[0022] 1. The fireproof smoke exhaust duct of the present application has adjacent pipe bodies connected by a first mounting plate and a second mounting plate, which has low operation difficulty and a firm and stable structure, and is conducive to improving the safety of the fireproof smoke exhaust duct; by coating the first gypsum layer and the second gypsum layer on both sides of the inner and outer sides of the rock wool layer, the fire resistance limit of the fireproof smoke exhaust duct can be improved to be greater than 2 hours, and the floor height can be saved while ensuring the appearance, avoiding the situation where construction cannot be carried out due to insufficient reserved height in the early stage, and meeting the owner's requirements for the net height; wherein, gypsum (CaSO4·2H2O) has a large amount of crystal water (about 21% by weight), which will evaporate in the event of a fire, absorb heat energy, provide a longer escape time, and prevent the protected components from being heated prematurely.

[0023] 2. In the preparation method of the fireproof smoke exhaust duct of the present application, the addition of glass fiber mesh cloth can not only ensure that it will not be corroded by wet materials, but also make the structure of the gypsum layer more solid; in addition, the layers do not need to be bonded with glue, but the gypsum slurry is poured on the rock wool insulation layer on the production line to form an integrated whole. The length of the duct can be cut to a fixed length, and the production process is energy-saving and environmentally friendly. At the same time, the surface flatness of the duct and the bonding strength between the layers are guaranteed.

[0024] 3. In the preparation method of the fireproof smoke exhaust duct of the present application, the first gypsum layer and the second gypsum layer are both made of gypsum powder as raw materials, and fly ash and dolomite powder are mixed as fine particles to fill the gaps in the internal structure with gypsum as the skeleton, thereby improving the density of the gypsum layer material, thereby making the duct stronger, and at the same time, it can also adsorb the free sodium, potassium, and chloride ions in the gypsum into its own structure, further improving the bonding performance between the layers; during the production process, the modified starch migrates to the interface with the water vapor, and can give full play to its bonding effect, so that the wood fiber and the gypsum slurry are closely combined, thereby improving the gypsum layer material The strength, moisture absorption and bonding properties of the material are improved; the combined effect of polyvinyl alcohol emulsion and silicone waterproofing agent can form a breathable and water-permeable protective film with excellent durability, preventing the gypsum layer from cracking and peeling, greatly improving the service life of the air duct; after adding calcium lignin sulfonate, not only can the water consumption be reduced, but also due to the increased sliding ability between gypsum particles, the gypsum hydration can be more sufficient, which is beneficial to improve the strength of the gypsum layer material; the addition of plant protein retarders prolongs the setting time of gypsum, ensures that the gypsum layer is fully solidified, reduces problems such as surface unevenness and weak bonding, and thus improves the quality of the air duct.

[0025] 4. In the preparation method of the fireproof smoke exhaust duct of the present application, the added composite flame retardant works synergistically with the gypsum base material to further improve the fireproof performance of the duct and extend its fire resistance limit; wherein, the acid source, carbon source, and gas source in ammonium polyphosphate, pentaerythritol, and melamine cooperate with each other to ensure a carbon layer of a certain strength, and the release of non-combustible gas causes the carbon layer to expand, thereby forming an insulating and expanding carbon layer, which prevents the inner layer of combustibles from further decomposing and improves the flame retardant efficiency; by using ammonium polyphosphate with an appropriate degree of polymerization, while ensuring good thermal stability, its thermal decomposition temperature is further increased, so that the duct can achieve better fireproof performance during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0027] Figure 1 This is a schematic diagram of the structure of the fire-proof smoke exhaust duct involved in an embodiment of the present application.

[0028] Figure 2 It is a schematic side cross-sectional view of the fireproof smoke exhaust duct involved in an embodiment of the present application.

[0029] List of parts and reference numerals:

[0030] 1. Tube body, 2. First mounting plate, 3. Second mounting plate, 4. Fiberglass mesh cloth, 5. Fireproof board, 51. First gypsum layer, 52. Rock wool layer, 53. Second gypsum layer, 6. Positioning groove, 61. Fitting groove, 62. Snap-in groove, 7. Positioning protrusion, 71. Fitting protrusion, 72. Snap-in protrusion, 8. First through hole, 9. Second through hole, 10. Sealing strip. DETAILED DESCRIPTION

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] If no specific conditions are specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The raw materials or instruments used, if no manufacturer is specified, are all conventional products that can be purchased commercially.

[0033] refer to Figure 1 and Figure 2The present application provides a fireproof smoke exhaust duct, comprising a plurality of pipe bodies 1 connected in sequence, wherein a first mounting plate 2 and a second mounting plate 3 are respectively provided at both ends of the pipe body 1, and adjacent pipe bodies 1 are connected by the first mounting plate 2 and the second mounting plate 3, which has low operation difficulty, a firm and stable structure, and is conducive to improving the safety of the fireproof smoke exhaust duct;

[0034] The pipe body 1 includes a fireproof board 5, which includes a first gypsum layer 51, a rock wool layer 52 and a second gypsum layer 53 connected in sequence from the inside to the outside, so as to further improve the fire resistance limit of the air duct and reduce fire losses.

[0035] It can be understood that the glass fiber mesh cloth 4 is arranged in the first gypsum layer 51 and the second gypsum layer 53, which can not only ensure that they will not be corroded by wet materials, but also make the structure of the gypsum layer more solid.

[0036] As an implementation mode, positioning grooves 6 are provided on the four sides of the first mounting plate 2, and positioning protrusions 7 are provided on the four sides of the second mounting plate 3. The positioning grooves 6 are snap-fitted with the positioning protrusions 7 to make the connection between adjacent tube bodies 1 tighter and more stable, and to facilitate later maintenance.

[0037] As an embodiment, the positioning groove 6 includes a fitting groove 61 and a snap-fitting groove 62 relatively arranged on both sides of the fitting groove 61, and the positioning protrusion 7 includes a fitting protrusion 71 and a snap-fitting protrusion 72 relatively arranged on both sides of the fitting protrusion 71. The fitting groove 61 fits with the fitting protrusion 71, and the snap-fitting groove 62 snaps with the snap-fitting protrusion 72, ensuring that the first mounting plate 2 and the second mounting plate 3 can be accurately aligned when connected to avoid misalignment or deviation, which not only improves the connection stability of adjacent pipe bodies 1, but also ensures the sealing of the entire fire-proof smoke exhaust duct system.

[0038] As an embodiment, the four corners of the first mounting plate 2 are each provided with a first through hole 8, and the four corners of the second mounting plate 3 are each provided with a second through hole 9. The fastening bolts pass through the first through hole 8 and the second through hole 9 in sequence and are then connected with nuts to fix the first mounting plate 2 and the second mounting plate 3, thereby realizing a fastened connection between adjacent pipes.

[0039] It can be understood that a washer is provided between the first mounting plate 2 and the second mounting plate 3 and is sleeved on the fastening bolt, which increases the contact area between the bolt and the mounting plate, thereby effectively dispersing the stress generated by the bolt during the fastening process and preventing local damage caused by stress concentration.

[0040] As an implementation mode, the thickness ratio of the first gypsum layer 51, the rock wool layer 52 and the second gypsum layer 53 is (1-3): (10-30): (1-3), preferably 2:20:2, which ensures the strength of the air duct while exerting its best fire resistance.

[0041] The splicing process involved below includes the process of surrounding the tube body 1 with four fireproof panels 5; wherein, adjacent fireproof panels 5 are connected by mortise and tenon structures, the outer side of the mortise and tenon structures are coated with sealing strips 10, and are fastened by bolts so as to tightly fix the fireproof panels 5 together to prevent separation due to external forces, and to maintain its structural stability in emergency situations such as fire, thereby extending the service life of the fireproof smoke exhaust duct.

[0042] The production method of the fireproof smoke exhaust duct is described in detail below through examples and comparative examples.

[0043] Example 1

[0044] A method for preparing a fireproof smoke exhaust duct comprises the following steps:

[0045] (1) adding polyvinyl alcohol emulsion, silicone waterproofing agent and water into a disperser, stirring at 3000 r / min for 30 min, then adding gypsum powder, modified starch, wood fiber, dolomite powder, fly ash, composite flame retardant, calcium lignin sulfonate and plant protein retarder, and continuing stirring for 30 min to obtain gypsum slurry;

[0046] (2) pouring gypsum slurry on the inner and outer surfaces of the rock wool tape respectively, and covering each with a layer of glass fiber mesh cloth, so that the glass fiber mesh cloth is embedded in the gypsum slurry, and drying to obtain a semi-finished product;

[0047] (3) splicing the semi-finished products obtained above to obtain a fireproof smoke exhaust duct;

[0048] Wherein, based on the weight of gypsum powder, the weight of modified starch is 0.1%, the weight of wood fiber is 2%, the weight of dolomite powder is 3%, the weight of fly ash is 20%, the weight of compound flame retardant is 10%, the weight of calcium lignin sulfonate is 0.3%, and the weight of plant protein retarder is 0.05%;

[0049] Based on the weight of water, the weight of the polyvinyl alcohol emulsion is 2% and the weight of the silicone waterproofing agent is 3%;

[0050] The compound flame retardant is ammonium polyphosphate, pentaerythritol and melamine in a weight ratio of 1.5:0.5:0.5;

[0051] The degree of polymerization of ammonium polyphosphate is 1000.

[0052] Example 2

[0053] A method for preparing a fireproof smoke exhaust duct comprises the following steps:

[0054] (1) adding polyvinyl alcohol emulsion, silicone waterproofing agent and water into a disperser, stirring at 3500 r / min for 25 min, then adding gypsum powder, modified starch, wood fiber, dolomite powder, fly ash, composite flame retardant, calcium lignin sulfonate and plant protein retarder, and continuing stirring for 40 min to obtain gypsum slurry;

[0055] (2) pouring gypsum slurry on the inner and outer surfaces of the rock wool tape respectively, and covering each with a layer of glass fiber mesh cloth, so that the glass fiber mesh cloth is embedded in the gypsum slurry, and drying to obtain a semi-finished product;

[0056] (3) splicing the semi-finished products obtained above to obtain a fireproof smoke exhaust duct;

[0057] Among them, based on the weight of gypsum powder, the weight of modified starch is 0.3%, the weight of wood fiber is 4%, the weight of dolomite powder is 5%, the weight of fly ash is 25%, the weight of compound flame retardant is 12%, the weight of calcium lignin sulfonate is 0.5%, and the weight of plant protein retarder is 0.08%;

[0058] Based on the weight of water, the weight of the polyvinyl alcohol emulsion is 3% and the weight of the silicone waterproofing agent is 4%;

[0059] The compound flame retardant is ammonium polyphosphate, pentaerythritol and melamine in a weight ratio of 2:1:1;

[0060] The degree of polymerization of ammonium polyphosphate is 1500.

[0061] Example 3

[0062] A method for preparing a fireproof smoke exhaust duct comprises the following steps:

[0063] (1) adding polyvinyl alcohol emulsion, silicone waterproofing agent and water into a disperser, stirring at 4000 r / min for 20 min, then adding gypsum powder, modified starch, wood fiber, dolomite powder, fly ash, composite flame retardant, calcium lignin sulfonate and plant protein retarder, and continuing stirring for 50 min to obtain gypsum slurry;

[0064] (2) pouring gypsum slurry on the inner and outer surfaces of the rock wool tape respectively, and covering each with a layer of glass fiber mesh cloth, so that the glass fiber mesh cloth is embedded in the gypsum slurry, and drying to obtain a semi-finished product;

[0065] (3) splicing the semi-finished products obtained above to obtain a fireproof smoke exhaust duct;

[0066] Wherein, based on the weight of gypsum powder, the weight of modified starch is 0.5%, the weight of wood fiber is 5%, the weight of dolomite powder is 6%, the weight of fly ash is 30%, the weight of compound flame retardant is 15%, the weight of calcium lignin sulfonate is 0.8%, and the weight of plant protein retarder is 0.1%;

[0067] Based on the weight of water, the weight of the polyvinyl alcohol emulsion is 4% and the weight of the silicone waterproofing agent is 5%;

[0068] The compound flame retardant is ammonium polyphosphate, pentaerythritol and melamine in a weight ratio of 3:1.2:1.2;

[0069] The degree of polymerization of ammonium polyphosphate is 2000.

[0070] Example 4

[0071] The difference from Example 2 is that step (2) is:

[0072] The gypsum slurry is poured on the outer surface of the rock wool tape and covered with a layer of glass fiber mesh cloth, so that the glass fiber mesh cloth is embedded in the gypsum slurry, and a semi-finished product is obtained after drying; that is, the obtained fireproof smoke exhaust duct does not contain the first gypsum layer.

[0073] Example 5

[0074] The difference from Example 2 is that step (2) is:

[0075] The gypsum slurry is poured on the inner surface of the rock wool tape and covered with a layer of glass fiber mesh cloth, so that the glass fiber mesh cloth is embedded in the gypsum slurry and dried to obtain a semi-finished product; that is, the obtained fireproof smoke exhaust duct does not contain a second gypsum layer.

[0076] Example 6

[0077] The difference from Example 2 is that the weight ratio of ammonium polyphosphate, pentaerythritol and melamine is 1:0.1:2.

[0078] Example 7

[0079] The difference from Example 2 is that the degree of polymerization of ammonium polyphosphate is 20.

[0080] Comparative Example 1

[0081] A method for preparing a fireproof smoke exhaust duct comprises the following steps:

[0082] The rock wool is coated on the outer surface of the color steel pipe to obtain a fireproof smoke exhaust duct.

[0083] Comparative Example 2

[0084] A method for preparing a fireproof smoke exhaust duct comprises the following steps:

[0085] The centrifugal glass wool is coated on the outer surface of the color steel pipe to obtain a fireproof smoke exhaust duct.

[0086] Comparative Example 3

[0087] A method for preparing a fireproof smoke exhaust duct comprises the following steps:

[0088] The fireproof fiber cotton coil is wrapped on the outer surface of the color steel pipe to obtain a fireproof smoke exhaust duct.

[0089] The performance of the fireproof smoke exhaust duct prepared by the above preparation method was tested, and the results are shown in Table 1.

[0090] Table 1

[0091]

[0092]

[0093] It can be seen from Table 1 that the fireproof smoke exhaust duct provided by the present invention maintains better integrity during the test process than traditional ducts of the same type, has a longer fire resistance limit and higher mechanical strength, is beautiful and saves floor height, avoids the situation where construction cannot be carried out due to insufficient reserved height in the early stage, is also moisture-proof, and has a wider range of applications.

[0094] The present application does not impose any specific restrictions on the connection method between the first mounting plate and the second mounting plate at both ends of the tube body, as long as a tight connection between the tube body and the first mounting plate and the second mounting plate can be achieved.

[0095] The above is only the embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application should be included in the protection scope of the present application.

Claims

1. A fireproof smoke exhaust duct, characterized in that: It comprises a plurality of pipe bodies connected in sequence, wherein the two ends of the pipe bodies are respectively provided with a first mounting plate and a second mounting plate, and the adjacent pipe bodies are connected through the first mounting plate and the second mounting plate; The pipe body comprises a fireproof board, and the fireproof board comprises a first gypsum layer, a rock wool layer and a second gypsum layer which are sequentially connected from the inside to the outside.

2. The fireproof smoke exhaust duct according to claim 1, characterized in that: The four sides of the first mounting plate are all provided with positioning grooves, and the four sides of the second mounting plate are all provided with positioning protrusions, and the positioning grooves are snap-connected with the positioning protrusions.

3. The fireproof smoke exhaust duct according to claim 2, characterized in that: The positioning groove includes a fitting groove and clamping grooves relatively arranged on both sides of the fitting groove, and the positioning protrusion includes a fitting protrusion and clamping protrusions relatively arranged on both sides of the fitting protrusion. The fitting groove fits with the fitting protrusion, and the clamping groove clamps with the clamping protrusion.

4. The fireproof smoke exhaust duct according to claim 1, characterized in that: The first mounting plate is provided with first through holes at four corners, and the second mounting plate is provided with second through holes at four corners. The fastening bolts pass through the first through holes and the second through holes in sequence and then are connected with nuts to fix the first mounting plate and the second mounting plate.

5. The fireproof smoke exhaust duct according to claim 1, characterized in that: The thickness ratio of the first gypsum layer, the rock wool layer and the second gypsum layer is (1-3):(10-30):(1-3).

6. A method for preparing a fireproof smoke exhaust duct according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) adding polyvinyl alcohol emulsion, silicone waterproofing agent and water into a disperser, stirring at 3000-4000 r / min for 20-30 min, then adding gypsum powder, modified starch, wood fiber, dolomite powder, fly ash, composite flame retardant, calcium lignin sulfonate and vegetable protein retarder, and continuing stirring for 30-50 min to obtain gypsum slurry; (2) pouring gypsum slurry on the inner and outer surfaces of the rock wool tape respectively, and covering each with a layer of glass fiber mesh cloth, so that the glass fiber mesh cloth is embedded in the gypsum slurry, and obtaining a semi-finished product after drying; (3) The semi-finished products obtained above are spliced ​​together to obtain a fireproof smoke exhaust duct.

7. The method for preparing a fireproof smoke exhaust duct according to claim 6, characterized in that: Based on the weight of gypsum powder, the weight of the modified starch is 0.1-0.5%, the weight of wood fiber is 2-5%, the weight of dolomite powder is 3-6%, the weight of fly ash is 20-30%, the weight of the composite flame retardant is 10-15%, the weight of calcium lignin sulfonate is 0.3-0.8%, and the weight of the plant protein retarder is 0.05-0.1%; Based on the weight of water, the weight of the polyvinyl alcohol emulsion is 2-4%, and the weight of the organosilicon waterproofing agent is 3-5%.

8. The method for preparing a fireproof smoke exhaust duct according to claim 6, characterized in that: The compound flame retardant is ammonium polyphosphate, pentaerythritol and melamine in a weight ratio of (1.5-3): (0.5-1.2): (0.5-1.2).

9. The method for preparing a fireproof smoke exhaust duct according to claim 8, characterized in that: The degree of polymerization of the ammonium polyphosphate is 1000-2000.

10. The method for preparing a fireproof smoke exhaust duct according to claim 6, characterized in that: The silane coupling agent is selected from at least one of KH-540, KH-550 and KH-792.

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