A polyurethane composite board for building exterior wall insulation and its preparation process

Abstract

The invention relates to the technical field of building material thermal insulation, in particular to a polyurethane composite board for building exterior wall thermal insulation and a preparation process thereof. The invention uses 4-hydroxy-3-nitrobenzaldehyde containing terminal nitro groups and terminal hydroxyl groups to mix with phenyl dichlorophosphate, and under the reaction of tin chloride, the nitro groups are reduced to terminal amino groups to generate a phosphorus-rich prepolymer with reaction activity and containing a large amount of nitrogen and phosphorus elements, and then the prepolymer is reacted with a polyurethane prepolymer still containing unreacted isocyanate groups to copolymerize to obtain a flame-retardant modified polyurethane. On this basis, the invention further mixes the prepolymer with different component materials to obtain a polyurethane foaming layer and a hard flame-retardant polyurethane layer, and hot-presses and combines them to finally obtain a polyurethane composite board with excellent thermal insulation and reliable flame retardancy.

Description

Technical Field

[0001] The invention relates to the technical field of building material thermal insulation, in particular to a polyurethane composite board for thermal insulation of building exterior walls and a preparation process thereof. Background Art

[0002] Polyurethane insulation board is a lightweight insulation material. It contains a large amount of closed-cell polyurethane foam components, which can absorb noise and block heat transmission. Therefore, it is often used in the field of building decoration. However, as a polymer material, polyurethane itself has poor flame retardancy and there are many safety hazards. Therefore, in order to enhance the performance of polyurethane materials, it is necessary to modify the flame retardancy of polyurethane composite boards. Summary of the invention

[0003] The object of the present invention is to provide a polyurethane composite board for building exterior wall insulation and a preparation process thereof, so as to solve the problems raised in the above-mentioned background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: A polyurethane composite board for building exterior wall insulation, having the following characteristics: The polyurethane composite board for building exterior wall insulation is composed of a flame-retardant polyurethane foam layer in the center and hard flame-retardant polyurethane layers on both sides;

[0005] Wherein, the polyurethane foam layer is composed of 30-50 parts of flame retardant modified polyurethane masterbatch, 0.25-0.4 parts of foaming agent, 5-8 parts of flame retardant, and 0.3-0.8 parts of foaming agent by weight;

[0006] The hard flame-retardant polyurethane layer is composed of 40-60 parts of flame-retardant modified polyurethane masterbatch, 2-3 parts of color masterbatch, 10-20 parts of flame retardant, 20-35 parts of reinforcing fiber and 3-6 parts of antioxidant.

[0007] Furthermore, the foaming agent is trifluorotrichloroethane; the flame retardant is antimony trioxide; and the foam leveling agent is polydimethylsiloxane.

[0008] Furthermore, the reinforcing fiber is glass fiber; and the antioxidant is phosphite.

[0009] A preparation process of a polyurethane composite board for building exterior wall insulation comprises the following steps:

[0010] S1. Preparation of flame retardant modified polyurethane masterbatch;

[0011] S11. Dissolve 4-hydroxy-3-nitrobenzaldehyde in tetrahydrofuran, stir to mix, and treat in an ice-water bath. After the temperature stabilizes, add diethylamine dropwise, mix evenly, add cuprous iodide, and then add phenyl dichlorophosphate dropwise. The addition time is 4-6 hours. After the addition is completed, heat to 20-25°C, stir to react for 36-72 hours, filter and collect the filtered product, and vacuum dry to constant weight;

[0012] S12. The filtered product was dissolved in anhydrous ethanol, tin chloride was added, and hydrochloric acid was added dropwise to adjust the pH to 1-2. After stirring and reacting at 20-30° C. for 8-12 hours, sodium hydroxide was added dropwise to neutralize until neutral, filtered, and the filtrate was mixed with chloroform, extracted, and the organic phase was separated. After evaporation and concentration, it was washed with cold dichloromethane to obtain a phosphorus-rich prepolymer;

[0013] S13. 1,4-butanediol is heated to 105-110° C., reacted under negative pressure for 0.5-1 h, cooled to 60-70° C., isophorone diisocyanate is slowly added dropwise, dibutyltin dilaurate is added, and the reaction is kept at this temperature for 12-18 h to obtain a polyurethane prepolymer;

[0014] S14: dissolving the phosphorus-rich prepolymer in N,N-dimethylformamide, adding the polyurethane prepolymer prepared in step S13, stirring and reacting for 18-24 hours, heating to 95-110° C. in a nitrogen atmosphere, and continuing the reaction for 2-3 hours. After the reaction is completed, vacuum drying, cooling and pelletizing are performed to obtain a flame-retardant modified polyurethane masterbatch;

[0015] S2. The flame retardant modified polyurethane masterbatch is mixed with a foaming agent, a flame retardant, and a homogenizing agent, kneaded at 190-210°C for 30-45min, heated to 215-230°C, and injection molded to obtain a polyurethane foam layer;

[0016] S3. The flame retardant modified polyurethane masterbatch is mixed with the masterbatch, the flame retardant, the reinforcing fiber, and the antioxidant, mixed at 200-210°C for 2-3h, heated to 220-240°C, and calendered to obtain a hard flame retardant polyurethane layer;

[0017] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing to obtain a polyurethane composite board.

[0018] The present invention is to enhance the flame retardant properties of polyurethane materials, and prepare a phosphorus-rich prepolymer. The present invention first uses 4-hydroxy-3-nitrobenzaldehyde containing terminal nitro and terminal hydroxyl groups as a raw material, and mixes it with phenyl dichlorophosphate to react, so that the hydroxyl group in 4-hydroxy-3-nitrobenzaldehyde replaces the chlorine element in phenyl dichlorophosphate, so that 4-hydroxy-3-nitrobenzaldehyde is grafted on phenyl dichlorophosphate; at the same time, in order to reduce the occurrence of side reactions, the present invention strictly controls the reaction temperature during the preparation process, first uses an ice-water bath to treat, so that the reaction system is in a stable state, and then gradually heats up. In this process, the hydroxyl group with higher reaction activity will take precedence over the aldehyde group and replace it with the chlorine element, so as to ensure the purity of the generated product. Afterwards, the present invention further reacts it with tin chloride, and the nitro group is reduced to an amino group so that it can react with an isocyanate group.

[0019] The phosphorus-rich prepolymer prepared by the present invention contains a large amount of N and P elements. When burning, the nitrogen-containing component will release a large amount of non-combustible gas, such as ammonia, nitrogen, water vapor and the like. Such gas will dilute the concentration of oxygen and combustible gas on the surface of the combustible material and absorb a large amount of heat, thereby achieving a flame retardant effect. In the combustion process, the phosphorus-containing component will generate PO· free radicals, which will bond with H· generated in the combustion process, thereby hindering the combustion reaction and achieving the purpose of flame retardancy.

[0020] When preparing the polyurethane prepolymer, in order to ensure that the polyurethane prepolymer still retains some isocyanate groups that can react with the phosphorus-rich prepolymer, the present application strictly limits the molar ratio of isocyanate to 1,4-butanediol, and mixes the polyurethane prepolymer with the phosphorus-rich prepolymer, thereby copolymerizing to obtain a flame-retardant modified polyurethane masterbatch.

[0021] Furthermore, in step S11, in terms of molar ratio, the mass ratio of 4-hydroxy-3-nitrobenzaldehyde, diethylamine, cuprous iodide and phenyl dichlorophosphate is (1.5-2): (2.5-3.4): (0.05-0.1): (0.7-1.2).

[0022] Furthermore, in step S12, the mass ratio of the filtered product to tin chloride is (10-15):(40-60) in parts by weight.

[0023] Furthermore, in step S13, in terms of molar ratio, the molar ratio of isophorone diisocyanate, 1,4-butanediol and dibutyltin dilaurate is (2-2.2):(0.9-1.4):(0.05-0.1).

[0024] Furthermore, in step S14, the mass ratio of the phosphorus-rich prepolymer to the polyurethane prepolymer is (0.3-0.8):(1.45-2) in parts by weight.

[0025] Furthermore, in step S4, the hot pressing bonding temperature is 210-215° C. and the pressure is 0.6-0.8 MPa.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention uses 4-hydroxy-3-nitrobenzaldehyde containing terminal nitro groups and terminal hydroxyl groups to mix with phenyl dichlorophosphate, and under the reaction of tin chloride, the nitro groups are reduced to terminal amino groups to generate a phosphorus-rich prepolymer with reaction activity and containing a large amount of nitrogen and phosphorus elements, and then the prepolymer is reacted with a polyurethane prepolymer still containing unreacted isocyanate groups to copolymerize to obtain a flame-retardant modified polyurethane; on this basis, the present application further mixes the prepolymer with different component materials to obtain a polyurethane foam layer and a hard flame-retardant polyurethane layer, and hot-presses them to finally obtain a polyurethane composite board with excellent thermal insulation and reliable flame retardancy. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1.

[0029] A preparation process of a polyurethane composite board for building exterior wall insulation, characterized in that it comprises the following steps:

[0030] S1. Preparation of flame retardant modified polyurethane masterbatch;

[0031] S11. Dissolve 1.5 mol of 4-hydroxy-3-nitrobenzaldehyde in 10 mol of tetrahydrofuran, stir and mix, treat in an ice-water bath, and after the temperature stabilizes, drop 2.5 mol of diethylamine for 4 hours. After the dropwise addition is completed, mix evenly, add 0.05 mol of cuprous iodide, and then drop 0.7 mol of phenyl dichlorophosphate for 4 hours. After the dropwise addition is completed, heat to 20°C, stir and react for 36 hours, filter and collect the filtered product, and dry in vacuum at 60°C to constant weight;

[0032] S12. 1 kg of the filtered product was dissolved in 8 kg of anhydrous ethanol, 4 kg of tin chloride was added, and hydrochloric acid was added dropwise to adjust the pH to 1. After stirring and reacting at 20 ° C for 8 hours, sodium hydroxide was added dropwise to neutralize until neutral, filtered, and an equal volume of chloroform was mixed with the filtrate, extracted, and the organic phase was separated. After evaporation and concentration, it was washed with cold dichloromethane to obtain a phosphorus-rich prepolymer;

[0033] S13. 0.9 mol of 1,4-butanediol was heated to 105° C., reacted under negative pressure for 0.5 h, cooled to 60° C., 2 mol of isophorone diisocyanate was slowly added dropwise, 0.05 mol of dibutyltin dilaurate was added, and the reaction was kept warm for 12 h to obtain a polyurethane prepolymer;

[0034] S14: dissolving 3 kg of phosphorus-rich prepolymer in 9 kg of N,N-dimethylformamide, adding 14.5 kg of the polyurethane prepolymer prepared in step S13, stirring and reacting for 18 hours, heating to 95° C. under a nitrogen atmosphere, and continuing to react for 2 hours. After the reaction is completed, vacuum drying, cooling and pelletizing are performed to obtain flame-retardant modified polyurethane masterbatch;

[0035] S2. 3kg of flame retardant modified polyurethane masterbatch was mixed with 0.025kg of trifluorotrichloroethane, 0.5kg of antimony trioxide and 0.03kg of polydimethylsiloxane, mixed at 190°C for 30min, heated to 215°C and injection molded to obtain a polyurethane foam layer;

[0036] S3. 4kg of flame-retardant modified polyurethane masterbatch was mixed with 0.2kg of masterbatch, 1kg of antimony trioxide, 2kg of glass fiber and 0.3kg of phosphite, mixed at 200°C for 2h, heated to 220°C, and calendered to obtain a hard flame-retardant polyurethane layer;

[0037] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing at a temperature of 210° C. and a pressure of 0.6 MPa to obtain a polyurethane composite board.

[0038] Example 2.

[0039] Compared with Example 1, this embodiment increases the amount of phosphorus-rich prepolymer added in step S14;

[0040] A preparation process of a polyurethane composite board for building exterior wall insulation, characterized in that it comprises the following steps:

[0041] S1. Preparation of flame retardant modified polyurethane masterbatch;

[0042] S11. Dissolve 1.5 mol of 4-hydroxy-3-nitrobenzaldehyde in 10 mol of tetrahydrofuran, stir and mix, treat in an ice-water bath, and after the temperature stabilizes, drop 2.5 mol of diethylamine for 4 hours. After the dropwise addition is completed, mix evenly, add 0.05 mol of cuprous iodide, and then drop 0.7 mol of phenyl dichlorophosphate for 4 hours. After the dropwise addition is completed, heat to 20°C, stir and react for 36 hours, filter and collect the filtered product, and dry in vacuum at 60°C to constant weight;

[0043] S12. 1 kg of the filtered product was dissolved in 8 kg of anhydrous ethanol, 4 kg of tin chloride was added, and hydrochloric acid was added dropwise to adjust the pH to 1. After stirring and reacting at 20 ° C for 8 hours, sodium hydroxide was added dropwise to neutralize until neutral, filtered, and an equal volume of chloroform was mixed with the filtrate, extracted, and the organic phase was separated. After evaporation and concentration, it was washed with cold dichloromethane to obtain a phosphorus-rich prepolymer;

[0044] S13. 0.9 mol of 1,4-butanediol was heated to 105° C., reacted under negative pressure for 0.5 h, cooled to 60° C., 2 mol of isophorone diisocyanate was slowly added dropwise, 0.05 mol of dibutyltin dilaurate was added, and the reaction was kept warm for 12 h to obtain a polyurethane prepolymer;

[0045] S14: 8 kg of phosphorus-rich prepolymer is dissolved in 20 kg of N,N-dimethylformamide, and 14.5 kg of the polyurethane prepolymer prepared in step S13 is added. After stirring for 18 hours, the temperature is raised to 95° C. under a nitrogen atmosphere, and the reaction is continued for 2 hours. After the reaction is completed, vacuum drying is performed, cooling and pelletizing are performed to obtain flame-retardant modified polyurethane masterbatch;

[0046] S2. 3kg of flame retardant modified polyurethane masterbatch was mixed with 0.025kg of trifluorotrichloroethane, 0.5kg of antimony trioxide and 0.03kg of polydimethylsiloxane, mixed at 190°C for 30min, heated to 215°C and injection molded to obtain a polyurethane foam layer;

[0047] S3. 4kg of flame-retardant modified polyurethane masterbatch was mixed with 0.2kg of masterbatch, 1kg of antimony trioxide, 2kg of glass fiber and 0.3kg of phosphite, mixed at 200°C for 2h, heated to 220°C, and calendered to obtain a hard flame-retardant polyurethane layer;

[0048] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing at a temperature of 210° C. and a pressure of 0.6 MPa to obtain a polyurethane composite board.

[0049] Example 3.

[0050] Compared with Example 2, this example increases the amount of phenyl dichlorophosphate added in step S11;

[0051] A preparation process of a polyurethane composite board for building exterior wall insulation, characterized in that it comprises the following steps:

[0052] S1. Preparation of flame retardant modified polyurethane masterbatch;

[0053] S11. Dissolve 1.5 mol of 4-hydroxy-3-nitrobenzaldehyde in 10 mol of tetrahydrofuran, stir and mix, treat in an ice-water bath, and after the temperature stabilizes, drop 2.5 mol of diethylamine for 4 hours. After the dropwise addition is completed, mix evenly, add 0.05 mol of cuprous iodide, and then drop 1.2 mol of phenyl dichlorophosphate for 4 hours. After the dropwise addition is completed, heat to 20°C, stir and react for 36 hours, filter and collect the filtered product, and dry in vacuum at 60°C to constant weight;

[0054] S12. 1 kg of the filtered product was dissolved in 8 kg of anhydrous ethanol, 4 kg of tin chloride was added, and hydrochloric acid was added dropwise to adjust the pH to 1. After stirring and reacting at 20 ° C for 8 hours, sodium hydroxide was added dropwise to neutralize until neutral, filtered, and an equal volume of chloroform was mixed with the filtrate, extracted, and the organic phase was separated. After evaporation and concentration, it was washed with cold dichloromethane to obtain a phosphorus-rich prepolymer;

[0055] S13. 0.9 mol of 1,4-butanediol was heated to 105° C., reacted under negative pressure for 0.5 h, cooled to 60° C., 2 mol of isophorone diisocyanate was slowly added dropwise, 0.05 mol of dibutyltin dilaurate was added, and the reaction was kept warm for 12 h to obtain a polyurethane prepolymer;

[0056] S14: 8 kg of phosphorus-rich prepolymer is dissolved in 20 kg of N,N-dimethylformamide, and 14.5 kg of the polyurethane prepolymer prepared in step S13 is added. After stirring for 18 hours, the temperature is raised to 95° C. under a nitrogen atmosphere, and the reaction is continued for 2 hours. After the reaction is completed, vacuum drying is performed, cooling and pelletizing are performed to obtain flame-retardant modified polyurethane masterbatch;

[0057] S2. 3kg of flame retardant modified polyurethane masterbatch was mixed with 0.025kg of trifluorotrichloroethane, 0.5kg of antimony trioxide and 0.03kg of polydimethylsiloxane, mixed at 190°C for 30min, heated to 215°C and injection molded to obtain a polyurethane foam layer;

[0058] S3. 4kg of flame-retardant modified polyurethane masterbatch was mixed with 0.2kg of masterbatch, 1kg of antimony trioxide, 2kg of glass fiber and 0.3kg of phosphite, mixed at 200°C for 2h, heated to 220°C, and calendered to obtain a hard flame-retardant polyurethane layer;

[0059] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing at a temperature of 210° C. and a pressure of 0.6 MPa to obtain a polyurethane composite board.

[0060] Example 4.

[0061] Compared with Example 2, this example increases the amount of 4-hydroxy-3-nitrobenzaldehyde added in step S11;

[0062] A preparation process of a polyurethane composite board for building exterior wall insulation, characterized in that it comprises the following steps:

[0063] S1. Preparation of flame retardant modified polyurethane masterbatch;

[0064] S11. Dissolve 2 mol of 4-hydroxy-3-nitrobenzaldehyde in 10 mol of tetrahydrofuran, stir and mix, treat in an ice-water bath, and after the temperature stabilizes, drop 2.5 mol of diethylamine for 4 hours. After the dropwise addition is completed, mix evenly, add 0.05 mol of cuprous iodide, and then drop 0.7 mol of phenyl dichlorophosphate for 4 hours. After the dropwise addition is completed, heat to 20°C, stir and react for 36 hours, filter and collect the filtered product, and dry in vacuum at 60°C to constant weight;

[0065] S12. 1 kg of the filtered product was dissolved in 8 kg of anhydrous ethanol, 4 kg of tin chloride was added, and hydrochloric acid was added dropwise to adjust the pH to 1. After stirring and reacting at 20 ° C for 8 hours, sodium hydroxide was added dropwise to neutralize until neutral, filtered, and an equal volume of chloroform was mixed with the filtrate, extracted, and the organic phase was separated. After evaporation and concentration, it was washed with cold dichloromethane to obtain a phosphorus-rich prepolymer;

[0066] S13. 0.9 mol of 1,4-butanediol was heated to 105° C., reacted under negative pressure for 0.5 h, cooled to 60° C., 2 mol of isophorone diisocyanate was slowly added dropwise, 0.05 mol of dibutyltin dilaurate was added, and the reaction was kept warm for 12 h to obtain a polyurethane prepolymer;

[0067] S14: 8 kg of phosphorus-rich prepolymer is dissolved in 20 kg of N,N-dimethylformamide, and 14.5 kg of the polyurethane prepolymer prepared in step S13 is added. After stirring for 18 hours, the temperature is raised to 95° C. under a nitrogen atmosphere, and the reaction is continued for 2 hours. After the reaction is completed, vacuum drying is performed, cooling and pelletizing are performed to obtain flame-retardant modified polyurethane masterbatch;

[0068] S2. 3kg of flame retardant modified polyurethane masterbatch was mixed with 0.025kg of trifluorotrichloroethane, 0.5kg of antimony trioxide and 0.03kg of polydimethylsiloxane, mixed at 190°C for 30min, heated to 215°C and injection molded to obtain a polyurethane foam layer;

[0069] S3. 4kg of flame-retardant modified polyurethane masterbatch was mixed with 0.2kg of masterbatch, 1kg of antimony trioxide, 2kg of glass fiber and 0.3kg of phosphite, mixed at 200°C for 2h, heated to 220°C, and calendered to obtain a hard flame-retardant polyurethane layer;

[0070] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing at a temperature of 210° C. and a pressure of 0.6 MPa to obtain a polyurethane composite board.

[0071] Example 5.

[0072] Compared with Example 2, this example increases the amount of flame retardant modified polyurethane masterbatch added in steps S2 and S3;

[0073] A preparation process of a polyurethane composite board for building exterior wall insulation, characterized in that it comprises the following steps:

[0074] S1. Preparation of flame retardant modified polyurethane masterbatch;

[0075] S11. Dissolve 1.5 mol of 4-hydroxy-3-nitrobenzaldehyde in 10 mol of tetrahydrofuran, stir and mix, treat in an ice-water bath, and after the temperature stabilizes, drop 2.5 mol of diethylamine for 4 hours. After the dropwise addition is completed, mix evenly, add 0.05 mol of cuprous iodide, and then drop 0.7 mol of phenyl dichlorophosphate for 4 hours. After the dropwise addition is completed, heat to 20°C, stir and react for 36 hours, filter and collect the filtered product, and dry in vacuum at 60°C to constant weight;

[0076] S12. 1 kg of the filtered product was dissolved in 8 kg of anhydrous ethanol, 4 kg of tin chloride was added, and hydrochloric acid was added dropwise to adjust the pH to 1. After stirring and reacting at 20 ° C for 8 hours, sodium hydroxide was added dropwise to neutralize until neutral, filtered, and an equal volume of chloroform was mixed with the filtrate, extracted, and the organic phase was separated. After evaporation and concentration, it was washed with cold dichloromethane to obtain a phosphorus-rich prepolymer;

[0077] S13. 0.9 mol of 1,4-butanediol was heated to 105° C., reacted under negative pressure for 0.5 h, cooled to 60° C., 2 mol of isophorone diisocyanate was slowly added dropwise, 0.05 mol of dibutyltin dilaurate was added, and the reaction was kept warm for 12 h to obtain a polyurethane prepolymer;

[0078] S14: 8 kg of phosphorus-rich prepolymer is dissolved in 20 kg of N,N-dimethylformamide, and 14.5 kg of the polyurethane prepolymer prepared in step S13 is added. After stirring for 18 hours, the temperature is raised to 95° C. under a nitrogen atmosphere, and the reaction is continued for 2 hours. After the reaction is completed, vacuum drying is performed, cooling and pelletizing are performed to obtain flame-retardant modified polyurethane masterbatch;

[0079] S2. 5kg of flame retardant modified polyurethane masterbatch was mixed with 0.025kg of trifluorotrichloroethane, 0.5kg of antimony trioxide and 0.03kg of polydimethylsiloxane, mixed at 190°C for 30min, heated to 215°C and injection molded to obtain a polyurethane foam layer;

[0080] S3. 6kg of flame retardant modified polyurethane masterbatch was mixed with 0.2kg of masterbatch, 1kg of antimony trioxide, 2kg of glass fiber and 0.3kg of phosphite, mixed at 200°C for 2h, heated to 220°C, and calendered to obtain a hard flame retardant polyurethane layer;

[0081] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing at a temperature of 210° C. and a pressure of 0.6 MPa to obtain a polyurethane composite board.

[0082] Example 6.

[0083] A preparation process of a polyurethane composite board for building exterior wall insulation, characterized in that it comprises the following steps:

[0084] S1. Preparation of flame retardant modified polyurethane masterbatch;

[0085] S11. Dissolve 2 mol of 4-hydroxy-3-nitrobenzaldehyde in 10 mol of tetrahydrofuran, stir and mix, treat in an ice-water bath, and after the temperature stabilizes, dropwise add 3.4 mol of diethylamine for 4 hours. After the dropwise addition is completed, mix evenly, add 0.1 mol of cuprous iodide, and then dropwise add 1.2 mol of phenyl dichlorophosphate for 4 hours. After the dropwise addition is completed, heat to 25°C, stir and react for 72 hours, filter and collect the filtered product, and dry in vacuum at 60°C to constant weight;

[0086] S12. 1.5 kg of the filtered product was dissolved in 8 kg of anhydrous ethanol, 6 kg of tin chloride was added, and hydrochloric acid was added dropwise to adjust the pH to 2. After stirring and reacting at 30 ° C for 12 hours, sodium hydroxide was added dropwise to neutralize to neutrality, filtered, and an equal volume of chloroform was mixed with the filtrate, extracted, and the organic phase was separated. After evaporation and concentration, it was washed with cold dichloromethane to obtain a phosphorus-rich prepolymer;

[0087] S13. 1.4 mol of 1,4-butanediol was heated to 110° C., reacted under negative pressure for 1 hour, cooled to 70° C., 2.2 mol of isophorone diisocyanate was slowly added dropwise, 0.1 mol of dibutyltin dilaurate was added, and the reaction was kept warm for 18 hours to obtain a polyurethane prepolymer;

[0088] S14: dissolving 8 kg of phosphorus-rich prepolymer in 20 kg of N,N-dimethylformamide, adding 20 kg of the polyurethane prepolymer prepared in step S13, stirring and reacting for 24 hours, heating to 110° C. under a nitrogen atmosphere, and continuing the reaction for 3 hours. After the reaction is completed, vacuum drying, cooling and pelletizing are performed to obtain flame-retardant modified polyurethane masterbatch;

[0089] S2. 5kg of flame retardant modified polyurethane masterbatch was mixed with 0.04kg of trifluorotrichloroethane, 0.8kg of antimony trioxide and 0.08kg of polydimethylsiloxane, mixed at 210°C for 45min, heated to 230°C and injection molded to obtain a polyurethane foam layer;

[0090] S3. 6kg flame retardant modified polyurethane masterbatch was mixed with 0.3kg color masterbatch, 2kg antimony trioxide, 3.5kg glass fiber and 0.6kg phosphite, mixed at 210°C for 2h, heated to 240°C, and calendered to obtain a hard flame retardant polyurethane layer;

[0091] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing at a temperature of 215° C. and a pressure of 0.8 MPa to obtain a polyurethane composite board.

[0092] Comparative Example 1.

[0093] Compared with Example 1, this comparative example does not prepare phosphorus-rich prepolymer, and this comparative example directly prepares polyurethane from polyamide prepolymer;

[0094] A preparation process of a polyurethane composite board for building exterior wall insulation, characterized in that it comprises the following steps:

[0095] S1. Preparation of polyurethane masterbatch;

[0096] S13. Heat 2 mol of 1,4-butanediol to 105° C., react under negative pressure for 0.5 h, cool to 60° C., slowly dropwise add 2 mol of isophorone diisocyanate, add 0.05 mol of dibutyltin dilaurate, and react for 12 h to obtain polyurethane; vacuum dry, cool and pelletize to obtain polyurethane masterbatch;

[0097] S2. 3kg of polyurethane masterbatch was mixed with 0.025kg of trifluorotrichloroethane, 0.5kg of antimony trioxide and 0.03kg of polydimethylsiloxane, mixed at 190°C for 30min, heated to 215°C and injection molded to obtain a polyurethane foam layer;

[0098] S3. 4kg polyurethane masterbatch was mixed with 0.2kg masterbatch, 1kg antimony trioxide, 2kg glass fiber and 0.3kg phosphite, mixed at 200°C for 2h, heated to 220°C, and calendered to obtain a hard flame-retardant polyurethane layer;

[0099] S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing at a temperature of 210° C. and a pressure of 0.6 MPa to obtain a polyurethane composite board.

[0100] Testing: Flame retardant properties were tested according to GB 8624-2012, smoke density levels were tested according to GB / T 8627, thermal conductivity was tested according to GB / T21558-2008. The test results are shown in the table below:

[0101]

[0102]

[0103] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing a polyurethane composite board for building exterior wall insulation, characterized in that: The following steps are involved: S1. Preparation of flame retardant modified polyurethane masterbatch; S11. Dissolve 4-hydroxy-3-nitrobenzaldehyde in tetrahydrofuran, stir to mix, and treat in an ice-water bath. After the temperature stabilizes, add diethylamine dropwise, mix evenly, add cuprous iodide, and then add phenyl dichlorophosphate dropwise. The addition time is 4-6 hours. After the addition is completed, heat to 20-25°C, stir to react for 36-72 hours, filter and collect the filtered product, and vacuum dry to constant weight; S12. The filtered product is dissolved in anhydrous ethanol, tin chloride is added, and hydrochloric acid is added dropwise to adjust the pH to 1-2. After stirring and reacting at 20-30° C. for 8-12 hours, sodium hydroxide is added dropwise to neutralize until neutral, the product is filtered, and the filtrate is mixed with chloroform, extracted, and the organic phase is separated. After evaporation and concentration, the product is washed with cold dichloromethane to obtain a phosphorus-rich prepolymer; S13. 1,4-butanediol is heated to 105-110°C, reacted under negative pressure for 0.5-1h, cooled to 60-70°C, isophorone diisocyanate is slowly added dropwise, dibutyltin dilaurate is added, and the reaction is carried out at the temperature for 12-18h to obtain a polyurethane prepolymer; S14: dissolving the phosphorus-rich prepolymer in N,N-dimethylformamide, adding the polyurethane prepolymer prepared in step S13, stirring and reacting for 18-24 hours, heating to 95-110° C. in a nitrogen atmosphere, and continuing the reaction for 2-3 hours. After the reaction is completed, vacuum drying, cooling and pelletizing are performed to obtain a flame-retardant modified polyurethane masterbatch; S2. Mix the flame retardant modified polyurethane masterbatch with the foaming agent, the flame retardant and the leveling agent, knead at 190-210°C for 30-45min, raise the temperature to 215-230°C, and perform injection molding to obtain a polyurethane foam layer; S3. Mix the flame retardant modified polyurethane masterbatch with the masterbatch, flame retardant, reinforcing fiber and antioxidant, mix at 200-210°C for 2-3h, heat to 220-240°C, and calender to obtain a hard flame retardant polyurethane layer; S4. Laminating the hard flame-retardant polyurethane layer to both sides of the polyurethane foam layer by hot pressing to obtain a polyurethane composite board.

2. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: The polyurethane composite board for building exterior wall insulation is composed of a central flame-retardant polyurethane foam layer and hard flame-retardant polyurethane layers on both sides; Wherein, the polyurethane foam layer is composed of 30-50 parts of flame retardant modified polyurethane masterbatch, 0.25-0.4 parts of foaming agent, 5-8 parts of flame retardant, and 0.3-0.8 parts of foaming agent by weight; The hard flame-retardant polyurethane layer is composed of 40-60 parts of flame-retardant modified polyurethane masterbatch, 2-3 parts of color masterbatch, 10-20 parts of flame retardant, 20-35 parts of reinforcing fiber and 3-6 parts of antioxidant.

3. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: The foaming agent is trifluorotrichloroethane; the flame retardant is antimony trioxide; and the foam leveling agent is polydimethylsiloxane.

4. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: The reinforcing fiber is glass fiber; and the antioxidant is phosphite.

5. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: In step S11, the molar ratio of 4-hydroxy-3-nitrobenzaldehyde, diethylamine, cuprous iodide and phenyl dichlorophosphate is (1.5-2): (2.5-3.4): (0.05-0.1): (0.7-1.2) in molar proportions.

6. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: In step S12, the mass ratio of the filtered product to tin chloride is (10-15): (40-60) in parts by weight.

7. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: In step S13, the molar ratio of isophorone diisocyanate, 1,4-butanediol and dibutyltin dilaurate is (2-2.2): (0.9-1.4): (0.05-0.1) in molar parts.

8. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: In step S14, the mass ratio of the phosphorus-rich prepolymer to the polyurethane prepolymer is (0.3-0.8): (1.45-2) in parts by weight.

9. The process for preparing a polyurethane composite board for building exterior wall insulation according to claim 1, characterized in that: In step S4, the hot pressing bonding temperature is 210-215° C. and the pressure is 0.6-0.8 MPa.

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