A method for preparing a cold-bridge-proof sandwich panel

Abstract

This invention discloses a method for preparing a cold bridge prevention material for sandwich panels, relating to the field of sandwich insulation panel technology. The invention uses isosorbide and bisphenol A as initiators to prepare a polyether polyol. Its rigid structure provides strength support, while the flexible side chains enhance the toughness of the polyurethane pad, synergistically enhancing the strength and flexibility of the polyurethane pad and improving its mechanical properties and tear resistance. Activated carbon and magnesium hydroxide are compounded as fillers to form a reinforcing phase in the polyurethane foam slurry, synergistically improving the filler's strength, flame retardancy, long-term stability, and thermal insulation performance. Magnesium hydroxide has flame retardant properties, and treatment with a silane coupling agent improves the compatibility between magnesium hydroxide and the polyurethane system. The irregular layered structure of activated carbon can form a barrier layer on the material surface, achieving physical barrier and improving the thermal stability of the filler. Treatment of activated carbon with dopamine hydrochloride improves its mechanical properties and hydrophobicity.

Description

Technical Field

[0001] This invention relates to the field of sandwich insulation board technology, specifically a method for preparing a sandwich board to prevent cold bridges. Background Technology

[0002] Cold bridging in sandwich panels refers to a technology that uses special design and processes to prevent the formation of "cold bridges" at the seams, connection points, or through-holes of sandwich panels. In insulation structures, the thermal conductivity of these components (such as metal frames, connectors, and screws) is much higher than that of the surrounding insulation material, creating "gaps" for rapid heat transfer. This leads to a significant decrease in insulation performance and may cause problems such as condensation, mold growth, and increased energy consumption.

[0003] This technology is primarily applied in scenarios with stringent requirements for temperature, humidity, and cleanliness. Existing technologies use polyurethane pads to composite sandwich panels, improving the insulation at the joints. However, polyurethane undergoes plastic deformation under long-term continuous pressure, potentially loosening the connection system and affecting structural safety. Its weak shear resistance means it may deform or fail under lateral forces from wind loads or earthquakes, affecting connection stability. Furthermore, long-term exposure to ultraviolet radiation, high / low temperature cycles, or harsh, humid environments can cause polyurethane pads to age, become brittle, or pulverize, leading to a significant decrease in their thermal insulation and mechanical properties. Therefore, this invention proposes a method for preparing sandwich panels to prevent cold bridges, addressing the aforementioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a sandwich panel anti-cold bridge, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A sandwich panel anti-cold bridge includes a sandwich panel and a polyurethane pad disposed on one side of the sandwich panel.

[0006] A method for preparing a sandwich panel anti-cold bridge, comprising the following process: taking a sandwich panel, anti-cold bridge screws, and polyurethane pads, assembling and fixing them to obtain a sandwich panel anti-cold bridge.

[0007] Furthermore, the polyurethane pad is manufactured using the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add filler, silicone oil, amine catalyst, ammonium polyphosphate and foaming agent to the premix in sequence and put them into the reactor. Stir at 450~500 rpm for 1~2 hours. Then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate) and stir at 700~800 rpm for 2~3 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 1-2 hours, and then place it in a drying oven at 60-70℃ for 12-14 hours to obtain a polyurethane pad.

[0008] Furthermore, the polyurethane pad comprises the following components by weight: 70-80 parts polytetrahydrofuran diol, 5-8 parts polyether polyol, 15-20 parts filler, 2-2.5 parts silicone oil, 0.2-0.5 parts amine catalyst, 3-5 parts ammonium polyphosphate, 5-10 parts foaming agent, 40-50 parts isophorone diisocyanate, and 4-6 parts trimethylolpropane tris(3-mercaptopropionate).

[0009] Furthermore, the foaming agent is any one of water, carbon dioxide, and pentane.

[0010] Furthermore, the polyether polyol is prepared by the following process: isosorbide and bisphenol A are mixed and dehydrated under vacuum, a catalyst is added, and the mixture is kept at 130-150°C for 1-2 hours under a nitrogen atmosphere. 5-10 wt% of propylene oxide is added dropwise to activate the reaction. After reacting for 20-30 minutes, KH-560 (γ-glycidyl etheroxypropyltrimethoxysilane) and the remaining propylene oxide are added. The polymerization reaction is carried out at a pressure of 0.1-0.3 MPa for 30-120 minutes. Neopentyl glycol diglycidyl ether is added, and a second polymerization is carried out for 30-120 minutes. Vacuum degassing is performed for 20-30 minutes, the temperature is lowered to 60-70°C, filtered, and dried to obtain the polyether polyol.

[0011] Furthermore, the catalyst is a bimetallic cyanide complex (DMC).

[0012] Furthermore, the polyether polyol comprises the following components by weight: 30-40 parts isosorbide, 5-10 parts bisphenol A, 0.02-0.03 parts catalyst, 100-120 parts propylene oxide, 15-20 parts KH-560, and 2-3 parts neopentyl glycol diglycidyl ether.

[0013] In the above technical solution, isosorbide and bisphenol A are used as initiators. The furan ring in the isosorbide structure and the benzene ring in bisphenol A provide a rigid skeleton for the polyurethane pad. Silane coupling agent and neopentyl glycol diglycidyl ether are introduced to provide flexible side chains. Through crosslinking with active groups such as epoxy and hydroxyl groups, a branched polyether polyol is formed. The neopentyl group is a hydrophobic group, which improves durability and corrosion resistance. The crosslinking density of the polyurethane system is increased synergistically, enhancing the strength and flexibility of the polyurethane pad, and improving the mechanical properties and tear resistance of the polyurethane pad.

[0014] Furthermore, the filler is prepared by the following process: Step 1: Add dopamine hydrochloride to Tris-HCl (tris(hydroxymethyl)aminomethane) hydrochloride solution, stir to dissolve, and obtain dopamine solution; Step 2: Add activated carbon to the dopamine solution, shear and disperse, heat to react, filter, wash and dry after the reaction is complete; Step 3: Place magnesium hydroxide in a mixer and stir at 1000~1200 rpm. At a temperature of 60~80℃, spray the silane coupling agent solution in using a sprayer. Continue stirring until homogeneous, then turn off the mixer and cool to room temperature. Step 4: Combine the magnesium hydroxide and activated carbon obtained in the above steps to obtain the filler.

[0015] Furthermore, in step 2, the process conditions for the heating reaction are: stirring the reaction at a temperature of 50~60℃ for 8~10 hours.

[0016] Furthermore, the concentration of the dopamine solution is 6-8 g / L.

[0017] Furthermore, the mass ratio of activated carbon to dopamine solution is 1:(15~20).

[0018] Furthermore, in step 3, the mass ratio of magnesium hydroxide to silane coupling agent solution is (5~10):1.

[0019] Furthermore, in step 4, the mass ratio of magnesium hydroxide to activated carbon is (3~5):(1~3).

[0020] Furthermore, the pH of the Tris-HCl solution is 6.8–7.4.

[0021] Furthermore, the concentration of the Tris-HCl solution is 0.1~0.3 mol / L.

[0022] In the above technical solution, activated carbon and magnesium hydroxide are compounded as fillers, which can form a reinforcing phase in the polyurethane system, improving the tear resistance and abrasion resistance of the polyurethane pad. Magnesium hydroxide, as an environmentally friendly inorganic flame retardant, when compounded with activated carbon, allows the irregular layered structure of the activated carbon to form a barrier layer on the material surface, achieving physical barrier and improving the thermal stability of the filler. Treatment with dopamine hydrochloride improves the mechanical properties and hydrophobicity of activated carbon, enhancing the chemical corrosion resistance and flame retardancy of the polyurethane pad. The treated activated carbon and magnesium hydroxide synergistically improve the strength, flame retardancy, long-term stability, and thermal insulation performance of the filler. Treatment of magnesium hydroxide with a silane coupling agent improves the compatibility of magnesium hydroxide with the polyurethane system.

[0023] Furthermore, the silane coupling agent solution is prepared by the following process: anhydrous ethanol and deionized water are mixed and stirred evenly, silane coupling agent is added, and the mixture is stirred evenly for 1 to 2 hours at a temperature of 50 to 80°C to obtain the silane coupling agent solution.

[0024] Furthermore, the mass ratio of silane coupling agent, ethanol, and deionized water is 5:(70~75):(20~30).

[0025] Furthermore, the silane coupling agent is any one of KH-550 (γ-aminopropyltriethoxysilane), KH-560, and KH-570 (γ-methacryloyloxypropyltrimethoxysilane).

[0026] Furthermore, the shear dispersion process conditions are as follows: dispersion at a rate of 4000~4500 rpm for 20~30 min.

[0027] Furthermore, in step 2, the drying process conditions are: drying at a temperature of 60~70℃ for 3~4 hours.

[0028] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses isosorbide and bisphenol A as initiators to prepare polyether polyols with rigid structures and flexible side chains, thereby enhancing the strength and flexibility of polyurethane pads and improving their mechanical and tear resistance.

[0029] 2. This invention improves the tear resistance and abrasion resistance of polyurethane gaskets by adding magnesium hydroxide and activated carbon as fillers. Magnesium hydroxide, as an environmentally friendly inorganic flame retardant, forms a barrier layer on the material surface when combined with activated carbon, thanks to the irregular layered structure of the activated carbon, which provides physical barrier and improves the thermal stability of the filler. Treatment with dopamine hydrochloride enhances the mechanical properties and hydrophobicity of the activated carbon, thereby improving the chemical corrosion resistance and flame retardancy of the polyurethane gaskets. Treatment with a silane coupling agent improves the compatibility of magnesium hydroxide with the polyurethane system. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the following specific embodiments, unless otherwise specified, the number of “parts” refers to parts by mass; A sandwich panel anti-cold bridge includes a sandwich panel and a polyurethane pad disposed on one side of the sandwich panel; Polytetrahydrofuran diol, model: PTMEG-1000, viscosity (40℃, cp): 270; Silicone oil, model: GY01; Ammonium polyphosphate, brand name TF-201S; Amine catalyst, model: A33; Trimethylolpropane tris(3-mercaptopropionate), CAS: 33007-83-9; Isophorone diisocyanate, CAS: 4098-71-9; Isosorbide, CAS: 652-67-5; Bisphenol A, CAS: 80-05-7; Activated carbon, brand name TS-CP3250; Magnesium hydroxide, grade GY-MG4. Example

[0032] A method for preparing a sandwich panel anti-cold bridge, comprising the following process: taking a sandwich panel, anti-cold bridge screws, and polyurethane pads, assembling and fixing them to obtain a sandwich panel anti-cold bridge; Polyurethane pads are manufactured using the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add filler, silicone oil, amine catalyst, ammonium polyphosphate and pentane to the premix in sequence and put them into the reactor. Stir at 500 rpm for 2 hours. Then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate) and stir at 800 rpm for 3 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 2 hours, and then place it in a drying oven at 70°C for 14 hours to obtain a polyurethane pad. The polyurethane pad comprises the following components by weight: 80 parts polytetrahydrofuran diol, 8 parts polyether polyol, 20 parts filler, 2.5 parts silicone oil, 0.5 parts amine catalyst, 5 parts ammonium polyphosphate, 10 parts pentane, 50 parts isophorone diisocyanate, and 6 parts trimethylolpropane tris(3-mercaptopropionate). The polyether polyol was prepared by the following process: Isosorbide and bisphenol A were mixed and dehydrated under vacuum, DMC was added, and the mixture was kept at 150°C for 2 hours under a nitrogen atmosphere. 10 wt% of propylene oxide was added dropwise to activate the reaction. After reacting for 20 minutes, KH-560 and the remaining propylene oxide were added. The polymerization reaction was carried out for 120 minutes under a pressure of 0.3 MPa. Neopentyl glycol diglycidyl ether was added, and the secondary polymerization was carried out for 120 minutes. Vacuum degassing was carried out for 30 minutes, the temperature was lowered to 70°C, filtered, and dried to obtain the polyether polyol. The polyether polyol comprises the following components by weight: 40 parts isosorbide, 10 parts bisphenol A, 0.03 parts DMC, 120 parts propylene oxide, 20 parts KH-560, and 3 parts neopentyl glycol diglycidyl ether. The packing material is produced by the following process: Step 1: Add dopamine hydrochloride to Tris-HCl solution, stir to dissolve, and obtain dopamine solution; Step 2: Add activated carbon to the dopamine solution, disperse at 4500 rpm for 30 min, stir and react at 60℃ for 10 h, filter, wash, and dry at 70℃ for 4 h after the reaction is complete. Step 3: Place magnesium hydroxide in a mixer and stir at 1200 rpm. At 80°C, spray the silane coupling agent solution in using a sprayer. Continue stirring until homogeneous, then turn off the mixer and cool to room temperature. Step 4: Combine the magnesium hydroxide and activated carbon obtained in the above steps to obtain the filler; The concentration of the dopamine solution is 6 g / L; the mass ratio of activated carbon to dopamine solution is 1:15. In step 3, the mass ratio of magnesium hydroxide to silane coupling agent solution is 5:1; In step 4, the mass ratio of magnesium hydroxide to activated carbon is 3:1; the pH of the Tris-HCl solution is 7.4; and the concentration of the Tris-HCl solution is 0.1 mol / L. The silane coupling agent solution is prepared by the following process: anhydrous ethanol and deionized water are mixed and stirred evenly, KH-570 is added, and the mixture is stirred evenly for 2 hours at 80°C to obtain the silane coupling agent solution; the mass ratio of KH-570, ethanol and deionized water is 5:75:30. Example

[0033] A method for preparing a sandwich panel anti-cold bridge, comprising the following process: taking a sandwich panel, anti-cold bridge screws, and polyurethane pads, assembling and fixing them to obtain a sandwich panel anti-cold bridge; Polyurethane pads are manufactured using the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add filler, silicone oil, amine catalyst, ammonium polyphosphate and pentane to the premix in sequence and put them into the reactor. Stir at 450 rpm for 1 hour. Then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate) and stir at 700 rpm for 2 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 1 hour, and then place it in a drying oven at 60°C for 12 hours to obtain a polyurethane pad. The polyurethane pad comprises the following components by weight: 70 parts polytetrahydrofuran diol, 5 parts polyether polyol, 15 parts filler, 2 parts silicone oil, 0.2 parts amine catalyst, 3 parts ammonium polyphosphate, 5 parts pentane, 40 parts isophorone diisocyanate, and 4 parts trimethylolpropane tris(3-mercaptopropionate). The polyether polyol was prepared by the following process: isosorbide and bisphenol A were mixed and dehydrated under vacuum, DMC was added, and the mixture was kept at 130°C for 1 hour under a nitrogen atmosphere. 5 wt% of propylene oxide was added dropwise to activate the reaction. After reacting for 25 minutes, KH-560 and the remaining propylene oxide were added. The polymerization reaction was carried out for 30 minutes under a pressure of 0.1 MPa. Neopentyl glycol diglycidyl ether was added, and the reaction was carried out for a second polymerization for 30 minutes. Vacuum degassing was performed for 20 minutes, the temperature was lowered to 60°C, filtered, and dried to obtain the polyether polyol. The polyether polyol comprises the following components by weight: 30 parts isosorbide, 5 parts bisphenol A, 0.02 parts DMC, 100 parts propylene oxide, 15 parts KH-560, and 2 parts neopentyl glycol diglycidyl ether. The packing material is produced by the following process: Step 1: Add dopamine hydrochloride to Tris-HCl solution, stir to dissolve, and obtain dopamine solution; Step 2: Add activated carbon to the dopamine solution, disperse at 4500 rpm for 30 min, stir and react at 60℃ for 10 h, filter, wash, and dry at 70℃ for 4 h after the reaction is complete. Step 3: Place magnesium hydroxide in a mixer and stir at 1200 rpm. At 80°C, spray the silane coupling agent solution in using a sprayer. Continue stirring until homogeneous, then turn off the mixer and cool to room temperature. Step 4: Combine the magnesium hydroxide and activated carbon obtained in the above steps to obtain the filler; The concentration of the dopamine solution is 6 g / L; the mass ratio of activated carbon to dopamine solution is 1:18. In step 3, the mass ratio of magnesium hydroxide to silane coupling agent solution is 8:1; In step 4, the mass ratio of magnesium hydroxide to activated carbon is 4:2; the pH of the Tris-HCl solution is 7.4; and the concentration of the Tris-HCl solution is 0.2 mol / L. The silane coupling agent solution is prepared by the following process: anhydrous ethanol and deionized water are mixed and stirred evenly, KH-550 is added, and the mixture is stirred evenly for 1 hour at 50°C to obtain the silane coupling agent solution; the mass ratio of KH-550, ethanol and deionized water is 5:70:20. Example

[0034] A method for preparing a sandwich panel anti-cold bridge, comprising the following process: taking a sandwich panel, anti-cold bridge screws, and polyurethane pads, assembling and fixing them to obtain a sandwich panel anti-cold bridge; Polyurethane pads are manufactured using the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add filler, silicone oil, amine catalyst, ammonium polyphosphate and pentane to the premix in sequence and put them into the reactor. Stir at 450 rpm for 1.5 h. Then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate) and stir at 750 rpm for 2.5 min to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 1.5 hours, and then place it in a drying oven at 65°C for 13 hours to obtain a polyurethane pad. The polyurethane pad comprises the following components by weight: 75 parts polytetrahydrofuran diol, 6 parts polyether polyol, 18 parts filler, 2 parts silicone oil, 0.3 parts amine catalyst, 4 parts ammonium polyphosphate, 8 parts pentane, 45 parts isophorone diisocyanate, and 5 parts trimethylolpropane tris(3-mercaptopropionate). The polyether polyol was prepared by the following process: isosorbide and bisphenol A were mixed and dehydrated under vacuum, DMC was added, and the mixture was kept at 140°C for 1 hour under a nitrogen atmosphere. 5 wt% of propylene oxide was added dropwise to activate the reaction. After reacting for 30 minutes, KH-560 and the remaining propylene oxide were added. The polymerization reaction was carried out for 100 minutes under a pressure of 0.2 MPa. Neopentyl glycol diglycidyl ether was added, and the reaction was carried out for 100 minutes. Vacuum degassing was performed for 25 minutes, the temperature was lowered to 65°C, filtered, and dried to obtain the polyether polyol. The polyether polyol comprises the following components by weight: 35 parts isosorbide, 8 parts bisphenol A, 0.02 parts DMC, 110 parts propylene oxide, 16 parts KH-560, and 2.5 parts neopentyl glycol diglycidyl ether. The packing material is produced by the following process: Step 1: Add dopamine hydrochloride to Tris-HCl solution, stir to dissolve, and obtain dopamine solution; Step 2: Add activated carbon to the dopamine solution, disperse at 4500 rpm for 30 min, stir and react at 60℃ for 10 h, filter, wash, and dry at 70℃ for 4 h after the reaction is complete. Step 3: Place magnesium hydroxide in a mixer and stir at 1200 rpm. At 80°C, spray the silane coupling agent solution in using a sprayer. Continue stirring until homogeneous, then turn off the mixer and cool to room temperature. Step 4: Combine the magnesium hydroxide and activated carbon obtained in the above steps to obtain the filler; The concentration of the dopamine solution is 6 g / L; the mass ratio of activated carbon to dopamine solution is 1:20. In step 3, the mass ratio of magnesium hydroxide to silane coupling agent solution is 10:1; In step 4, the mass ratio of magnesium hydroxide to activated carbon is 5:3; the pH of the Tris-HCl solution is 7.4; and the concentration of the Tris-HCl solution is 0.3 mol / L. The silane coupling agent solution is prepared by the following process: anhydrous ethanol and deionized water are mixed and stirred evenly, KH-560 is added, and the mixture is stirred evenly for 1.5 h at 60°C to obtain the silane coupling agent solution; the mass ratio of KH-560, ethanol and deionized water is 5:72:25.

[0035] Comparative Example 1: A method for preparing a sandwich panel anti-cold bridge, wherein the polyurethane pad is prepared by the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; polyether polyol grade: YD-380; S2: Add filler, silicone oil, amine catalyst, ammonium polyphosphate and pentane to the premix in sequence and put them into the reactor. Stir at 450 rpm for 1 hour. Then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate) and stir at 700 rpm for 2 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 1 hour, and then place it in a drying oven at 60°C for 12 hours to obtain a polyurethane pad. The polyurethane pad comprises the following components by weight: 70 parts polytetrahydrofuran diol, 5 parts polyether polyol, 15 parts filler, 2 parts silicone oil, 0.2 parts amine catalyst, 3 parts ammonium polyphosphate, 5 parts pentane, 40 parts isophorone diisocyanate, and 4 parts trimethylolpropane tris(3-mercaptopropionate); the remaining process steps and component ratios are the same as in Example 1.

[0036] Comparative Example 2: A method for preparing a sandwich panel anti-cold bridge, wherein the polyurethane pad is prepared by the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add activated carbon, magnesium hydroxide, silicone oil, amine catalyst, ammonium polyphosphate, and pentane to the premix in sequence into a reactor, stir at 450 rpm for 1 hour, then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate), stir at 700 rpm for 2 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 1 hour, and then place it in a drying oven at 60°C for 12 hours to obtain a polyurethane pad. The polyurethane pad comprises the following components by weight: 70 parts polytetrahydrofuran diol, 5 parts polyether polyol, 15 parts activated carbon, 5 parts magnesium hydroxide, 2 parts silicone oil, 0.2 parts amine catalyst, 3 parts ammonium polyphosphate, 5 parts pentane, 40 parts isophorone diisocyanate, and 4 parts trimethylolpropane tris(3-mercaptopropionate); the remaining process steps and component ratios are the same as in Example 1.

[0037] Comparative Example 3: A method for preparing a sandwich panel anti-cold bridge, wherein the polyurethane pad is prepared by the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add magnesium hydroxide, silicone oil, amine catalyst, ammonium polyphosphate and pentane to the premix in sequence and put them into the reactor. Stir at 450 rpm for 1 hour. Then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate) and stir at 700 rpm for 2 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 1 hour, and then place it in a drying oven at 60°C for 12 hours to obtain a polyurethane pad. The polyurethane pad comprises the following components by weight: 70 parts polytetrahydrofuran diol, 5 parts polyether polyol, 15 parts magnesium hydroxide, 2 parts silicone oil, 0.2 parts amine catalyst, 3 parts ammonium polyphosphate, 5 parts pentane, 40 parts isophorone diisocyanate, and 4 parts trimethylolpropane tris(3-mercaptopropionate). The magnesium hydroxide was processed by the following steps: dry magnesium hydroxide was placed in a mixer and stirred at 1000 rpm. At a temperature of 60°C, a silane coupling agent solution was sprayed in using a sprayer. After stirring until homogeneous, the mixer was turned off and the mixture was cooled to room temperature. The mass ratio of magnesium hydroxide to silane coupling agent solution was 5:1. The remaining process steps and component ratios were the same as in Example 1.

[0038] Comparative Example 4: A method for preparing a sandwich panel anti-cold bridge, wherein the polyurethane pad is prepared by the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add activated carbon, silicone oil, amine catalyst, ammonium polyphosphate and pentane to the premix in sequence into the reactor, stir at 450 rpm for 1 hour, then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate), stir at 700 rpm for 2 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place for 1 hour, and then place it in a drying oven at 60°C for 12 hours to obtain a polyurethane pad. The polyurethane pad comprises the following components by weight: 70 parts polytetrahydrofuran diol, 5 parts polyether polyol, 15 parts activated carbon, 2 parts silicone oil, 0.2 parts amine catalyst, 3 parts ammonium polyphosphate, 5 parts pentane, 40 parts isophorone diisocyanate, and 4 parts trimethylolpropane tris(3-mercaptopropionate). Activated carbon is produced by the following process: Step 1: Add dopamine hydrochloride to Tris-HCl solution, stir to dissolve, and obtain dopamine solution; Step 2: Add activated carbon to the dopamine solution, disperse at 4000 rpm for 20 min, stir and react at 50℃ for 8 h, filter, wash, and dry at 60℃ for 3 h after the reaction is complete. The concentration of the dopamine solution was 6 g / L; the mass ratio of activated carbon to dopamine solution was 1:15; the pH of the Tris-HCl solution was 7.4; the concentration of the Tris-HCl solution was 0.1 mol / L; the remaining process steps and component ratios were the same as in Example 1.

[0039] Experiment: The sandwich panel anti-cold bridges obtained in Examples 1-3 and Comparative Examples 1-4 were used to prepare samples, and their performance was tested and the test results were recorded: Thermal conductivity test: Using GB / T 3399-1982 as the reference standard, under normal temperature and humidity conditions, the sample is placed between the hot and cold plates of the instrument, so that the sample is in close contact with the hot and cold plates, and the hot and cold plates are kept at a constant temperature and the temperature difference is maintained. When the temperature difference between the main heating plate and the protective heating plate is less than 0.1K, the temperature is considered to have reached equilibrium. The thermal conductivity is calculated and recorded. Flame retardant performance test: Using GB / T 2406.2-2009 as the reference standard, the limiting oxygen index of the sample was tested; Deformation rate test: Using GB / T 8811-2008 as the reference standard, the polyurethane pad block samples were kept at -80℃ for 72 hours and at 80℃ for 72 hours respectively, and the low temperature deformation rate and high temperature deformation rate were recorded.

[0040] Table 1

[0041] Based on the data in the table above, the following conclusions can be clearly drawn: The sandwich panel anti-cold bridges obtained in Examples 1-3 are compared with those obtained in Comparative Examples 1-4. The test results show that: Compared with Comparative Examples 1-4, the sandwich panels obtained in Examples 1-3 have better thermal insulation performance, better flame retardancy, and are less prone to deformation. Compared with Example 1, the sandwich panel cold bridge prevention obtained in Comparative Example 1, using commercially available polyether polyol, showed increased thermal conductivity, decreased limiting oxygen index, and high deformation rate. This indicates that the polyether polyol prepared in this invention improves the crosslinking density, thermal insulation, and structural stability of the polyurethane pad under low and high temperature conditions. The furan ring in the isosorbide structure and the benzene ring in bisphenol A provide a rigid skeleton for the polyurethane pad. The introduction of silane coupling agent and neopentyl glycol diglycidyl ether provides flexible side chains, synergistically enhancing the strength and flexibility of the polyurethane pad, thus verifying the importance of the polyether polyol of this invention. Compared with Example 1, the sandwich panel cold bridge prevention obtained in Comparative Example 2, with activated carbon and magnesium hydroxide directly compounded as fillers without treatment, showed an increase in thermal conductivity, a decrease in limiting oxygen index, and a high deformation rate. This indicates that direct compounding as fillers reduces compatibility with the polyurethane system, reduces uniformity and strength, and affects the stability, flame retardancy, and thermal insulation performance of the polyurethane pad. This demonstrates the technical advantages of the filler preparation process of the present invention. Compared with Example 1, the sandwich panels obtained in Comparative Examples 3-4, which used only dopamine-treated activated carbon or magnesium hydroxide treated with silane coupling agent, showed increased thermal conductivity, decreased limiting oxygen index, and high deformation rate. This indicates that dopamine-treated activated carbon and silane coupling agent-treated magnesium hydroxide can have a synergistic effect, improving the strength, flame retardancy, long-term stability, and thermal insulation performance of the filler. This further verifies the technical advantages of the filler preparation process of the present invention.

[0042] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A sandwich panel anti-cold bridge, characterized in that: The invention includes a sandwich panel and a polyurethane pad disposed on one side of the sandwich panel; the polyurethane pad comprises the following components by weight: 70-80 parts polytetrahydrofuran diol, 5-8 parts polyether polyol, 15-20 parts filler, 2-2.5 parts silicone oil, 0.2-0.5 parts amine catalyst, 3-5 parts ammonium polyphosphate, 5-10 parts blowing agent, 40-50 parts isophorone diisocyanate, and 4-6 parts trimethylolpropane tris(3-mercaptopropionate). The filler consists of magnesium hydroxide and activated carbon.

2. A method for preparing a sandwich panel anti-cold bridge, characterized in that: It is produced by the following process: take sandwich panels, anti-cold bridge screws, and polyurethane pads, assemble and fix them to obtain sandwich panel anti-cold bridge; The polyurethane pad is manufactured using the following process: S1: Polytetrahydrofuran diol and polyether polyol are vacuum dehydrated and then mixed and stirred evenly to obtain a premix; S2: Add filler, silicone oil, amine catalyst, ammonium polyphosphate and foaming agent to the premix in sequence and put them into the reactor. Stir for 1-2 hours, then add isophorone diisocyanate and trimethylolpropane tris(3-mercaptopropionate) and stir for 2-3 minutes to obtain polyurethane foam slurry. S3: Pour the polyurethane foam slurry into a mold, dry it in a ventilated place, and then place it in a drying oven to dry, thus obtaining a polyurethane pad.

3. The method for preparing a sandwich panel anti-cold bridge according to claim 2, characterized in that: The polyether polyol is prepared by the following process: isosorbide and bisphenol A are mixed and dehydrated under vacuum, a catalyst is added, and the mixture is kept at 130-150°C for 1-2 hours under a nitrogen atmosphere. 5-10 wt% of propylene oxide is added dropwise to activate the reaction. After reacting for 20-30 minutes, KH-560 and the remaining propylene oxide are added. The polymerization reaction is carried out at a pressure of 0.1-0.3 MPa for 30-120 minutes. Neopentyl glycol diglycidyl ether is added, and a secondary polymerization is carried out for 30-120 minutes. Vacuum degassing is performed for 20-30 minutes, the temperature is lowered to 60-70°C, filtered, and dried to obtain the polyether polyol.

4. The method for preparing a sandwich panel anti-cold bridge according to claim 3, characterized in that: The polyether polyol comprises the following components by weight: 30-40 parts isosorbide, 5-10 parts bisphenol A, 0.02-0.03 parts catalyst, 100-120 parts propylene oxide, 15-20 parts KH-560, and 2-3 parts neopentyl glycol diglycidyl ether.

5. The method for preparing a sandwich panel anti-cold bridge according to claim 2, characterized in that: The filler is prepared by the following process: Step 1: Add dopamine hydrochloride to Tris-HCl solution, stir to dissolve, and obtain dopamine solution; Step 2: Add activated carbon to the dopamine solution, shear and disperse, heat to react, filter, wash and dry after the reaction is complete; Step 3: Place magnesium hydroxide in a mixer and stir at 1000~1200 rpm. At a temperature of 60~80℃, spray the silane coupling agent solution in using a sprayer. Continue stirring until homogeneous, then turn off the mixer and cool to room temperature. Step 4: Combine the magnesium hydroxide and activated carbon obtained in the above steps to obtain the filler.

6. The method for preparing a sandwich panel anti-cold bridge according to claim 5, characterized in that: The concentration of dopamine solution is 6~8 g / L; the mass ratio of activated carbon to dopamine solution is 1:(15~20); the concentration of Tris-HCl solution is 0.1~0.3 mol / L.

7. The method for preparing a sandwich panel anti-cold bridge according to claim 5, characterized in that: In step 3, the mass ratio of magnesium hydroxide to silane coupling agent solution is (5~10):

1.

8. The method for preparing a sandwich panel anti-cold bridge according to claim 5, characterized in that: In step 4, the mass ratio of magnesium hydroxide to activated carbon is (3~5):(1~3).

9. The method for preparing a sandwich panel anti-cold bridge according to claim 7, characterized in that: The silane coupling agent is any one of KH-550, KH-560, and KH-570.

10. The method for preparing a sandwich panel anti-cold bridge according to claim 2, characterized in that: The foaming agent is any one of water, carbon dioxide, or pentane.

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