Flame-retardant rigid polyurethane foam polyol, and preparation method and application thereof

Abstract

The application discloses a kind of flame-retardant rigid foam polyether polyols and its preparation method and application.The preparation method of the polyether polyol includes the following processes: with the silane compound containing primary amino group and diphenyl halogenated phosphorus as raw material, under alkaline condition, intermediate is obtained; then with the intermediate as initiator, under the action of polymerization catalyst, polymerization reaction with alkylene oxide is carried out, and polyether polyol is prepared.The polyether polyol obtained by the application is prepared by using the reactant of silane compound containing primary amino group and diphenyl chlorinated phosphorus as initiator, and polymerizing with alkylene oxide, and the particularity of molecular structure is conducive to reducing the surface tension of foaming system, improving compatibility, making the foaming process stable and controllable, and the cell structure is more delicate, and the foam strength is higher, and the flame retardance is good.

Description

Technical Field

[0001] This invention relates to a polyether polyol, and more particularly to a flame-retardant rigid foam polyether polyol, its preparation method, and its application. Background Technology

[0002] Rigid polyurethane foam is widely used in insulation applications such as refrigerators, freezers, refrigerated trucks, and refrigerated containers due to its advantages including extremely low thermal conductivity, high compressive strength, and simple manufacturing process. Refrigerated trucks and containers, as crucial transport vehicles in cold chain logistics, face increasingly stringent market demands for safety, operational stability, and flame retardancy of materials. This requires rigid polyurethane foam to not only possess excellent thermal insulation and flame retardancy but also provide structural strength. Currently, it is difficult to simultaneously improve upon these multiple performance aspects. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention first proposes a flame-retardant rigid foam polyether polyol and its preparation method. The polyether polyol is prepared by polymerization of an oxidized olefin with a silane compound containing a primary amine group and a reactant of diphenylphosphine chloride as an initiator. The unique molecular structure helps reduce the surface tension of the foaming system, improves compatibility, makes the foaming process stable and controllable, results in a finer cell structure, and simultaneously produces high foam strength and good flame retardancy.

[0004] Secondly, this invention also provides the application of flame-retardant rigid foam polyether polyol in the preparation of rigid polyurethane foam. The resulting rigid polyurethane foam has many of the aforementioned advantages.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] As a first aspect of the present invention, a method for preparing flame-retardant rigid foam polyether polyol is provided, comprising the following steps:

[0007] A silane compound containing a primary amino group and diphenyl phosphorus halide were reacted under alkaline conditions to obtain an intermediate. Subsequently, the intermediate was used as an initiator to undergo a polymerization reaction with an oxidized olefin under the action of a polymerization catalyst to obtain a polyether polyol.

[0008] In some preferred preparation methods,

[0009] The molar ratio of the silane compound and the diphenyl phosphorus halide is 1-3:1;

[0010] Preferably, the silane compound is selected from one or more of 3-aminopropyltriethoxysilane, (3-aminopropyl)dimethylmethoxysilane, and (3-aminoethyl)dimethylmethoxysilane;

[0011] Preferably, the phenyl phosphorus halide is selected from one or more of diphenyl phosphorus chloride, phenyl dichloride, and (2-chlorophenyl)diphenylphosphine;

[0012] Preferably, the alkaline conditions for the reaction of the silane compound and diphenyl phosphorus halide are provided by an organic base and / or an inorganic base; the organic base is selected from one or more of triethylamine, dimethylethylamine, and diisopropylethylamine; the inorganic base is selected from one or more of sodium methoxide, potassium ethoxide, and potassium tert-butoxide.

[0013] The amount of the organic base and / or inorganic base used, in molar terms, is 0.5 to 2 times the molar amount of the silane compound.

[0014] In some preferred preparation methods, the oxidized olefin is one or more selected from ethylene oxide, propylene oxide, butane oxide, and tetrahydrofuran;

[0015] Preferably, the amount of the oxidized olefin is 2-8 times the molar amount of the corresponding silane compound;

[0016] Preferably, the polymerization catalyst is an alkaline catalyst and / or a bimetallic complex catalyst, more preferably one or more of potassium hydroxide, sodium hydroxide, potassium alkoxide, sodium alkoxide, MMC, and DMC;

[0017] Preferably, the amount of the polymerization catalyst is 1-3% of the mass of the corresponding silane compound.

[0018] In some preferred preparation methods, the reaction temperature of the silane compound and the diphenyl phosphorus halide is 35-45°C, and the reaction time is 1-3 hours.

[0019] Preferably, the polymerization reaction is divided into an esterification addition reaction stage and a vacuum ripening stage. The esterification addition reaction is carried out by stirring and heating the silane compound and the polymerization catalyst in a reaction vessel completely replaced with nitrogen to 120-150°C, and adding olefin oxides to react for 1-4 hours. After the esterification addition reaction is completed, the temperature is raised to 180-200°C and vacuum ripening is carried out while maintaining a pressure not exceeding 0.8 MPa to distill off the byproduct water and unreacted olefin oxides.

[0020] The above polymerization process is relatively conventional and easy to adjust for those skilled in the art, without considering the selection of initiator. For specific details, please refer to the various solutions disclosed in known technologies. No specific restrictions are imposed here.

[0021] It is worth noting that the reaction between the silane compound and diphenyl phosphorus halide is highly complete. Based on the consideration of saving reaction steps, the unreacted raw materials can be directly fed into the polymerization reaction for the next step of the reaction without separation. The light components can be removed in one step during the vacuum polycondensation stage.

[0022] In addition, after the polymerization reaction is complete and the curing is finished, polyether polyols are obtained through conventional post-processing steps such as neutralization, adsorption dehydration, and filtration. Suitable neutralizing agents include phosphoric acid, lactic acid, and acetic acid; suitable adsorbents include magnesium silicate, magnesium polysilicate, aluminum polysilicate, and diatomaceous earth; suitable filtration equipment includes vacuum filters, preferably performed under a vacuum of -0.09 MPa for a time of 0.5-1 hour. The filtrate is collected after filtration to obtain the polyether polyol.

[0023] As a second aspect of the present invention, a flame-retardant rigid foam polyether polyol prepared by the method described above is also provided, which has a functionality of 1, a hydroxyl value of 70-120 mgKOH / g, and a viscosity of 400-800 mPa*s at 25°C.

[0024] As a third aspect of the invention, a flame-retardant rigid polyurethane foam is also provided, comprising a polyisocyanate component and a combined polyether component, said combined polyether component comprising A) a polyol, B) a foaming agent and optionally C) an additive.

[0025] Wherein, A) the polyol includes the flame-retardant rigid foam polyether polyol prepared by the method described above; preferably, the mass content of the flame-retardant rigid foam polyether polyol prepared by the method described above in A) the polyol is 5 to 40 wt%.

[0026] In some preferred embodiments of the invention, the mass ratio of the polyisocyanate component to the combined polyether component is (1-1.5):1;

[0027] Preferably, the polyisocyanate component is polymeric MDI or liquefied modified MDI, and more preferably one or more of Wanhua PM200, PM400, and PM700;

[0028] Preferably, B) the amount of foaming agent used is 5-15% of the mass of the combined polyether components;

[0029] Preferably, the amount of additive C) is 10-20% of the mass of the polyether component.

[0030] In some preferred embodiments of the invention, A) the polyol may optionally include at least one of the following: a polyether polyol starting with sucrose, a polyether polyol starting with sorbitol, a polyether polyol starting with propylene glycol, and a polyester polyol starting with phthalic anhydride.

[0031] Preferably, the polyether polyol using sucrose as an initiator is a polyether polyol prepared by polymerization of propylene oxide and / or ethylene oxide with sucrose as an initiator, having a molecular weight of 300-800, a functionality of 4.5-6, and a hydroxyl value of 300-420 mgKOH / g; preferably, the mass fraction of the polyether polyol using sucrose as an initiator in polyol A) is ≤40wt% (e.g., 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, etc.), more preferably 5-40wt%;

[0032] Preferably, the polyether polyol using sorbitol as an initiator is a polyether polyol prepared by polymerization of propylene oxide and / or ethylene oxide with sorbitol as an initiator, having a molecular weight of 600-700, a functionality of 4.5-6, and a hydroxyl value of 400-500 mgKOH / g; preferably, the mass fraction of the polyether polyol using sorbitol as an initiator in polyol A) is ≤30wt% (e.g., 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, etc.), more preferably 5-30wt%;

[0033] Preferably, the polyether polyol using propylene glycol as an initiator is a polyether polyol prepared by polymerizing propylene glycol with propylene oxide and / or ethylene oxide, with a molecular weight of 400-1000, a functionality of 1.5-2, and a hydroxyl value of 400-800 mgKOH / g; preferably, the mass fraction of the polyether polyol using propylene glycol as an initiator in polyol A) is ≤30wt% (e.g., 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, etc.), preferably 5-30wt%.

[0034] Preferably, the polyester polyol using phthalic anhydride as an initiator has a molecular weight of 300-500, a functionality of 2, and a hydroxyl value of 220-350 mgKOH / g; the polyester polyol using phthalic anhydride as an initiator is preferably one or more of Stepan PS-3152, PS-2452, and PS-2352; preferably, the mass fraction of the polyester polyol using phthalic anhydride as an initiator in polyol A) is ≤20wt% (e.g., 5wt%, 10wt%, 15wt%, 20wt%, etc.), more preferably 5-20wt%.

[0035] In some preferred embodiments of the invention, the foaming agent is one or more of cyclopentane, isopentane, and n-pentane, or a mixture of at least one of cyclopentane, isopentane, and n-pentane and water.

[0036] In some preferred embodiments of the invention, the additive is one or more of flame retardants, surfactants, and catalysts;

[0037] Preferably, the flame retardant is tri(chloroisopropyl) phosphate and / or triethyl phosphate;

[0038] Preferably, the surfactant is a siloxane, and more preferably one or more of B8546, B84813, AK88310, and AK88719;

[0039] Preferably, the catalyst is an amine and / or a metal salt and / or water, more preferably one or more of pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, triethylenediamine, TMR-2, N,N-dimethylbenzylamine, potassium formate, potassium acetate, potassium isooctanoate, and water.

[0040] Finally, the present invention also provides a method for preparing flame-retardant rigid polyurethane foam, comprising the following steps:

[0041] (1) Mix the polyol, foaming agent and optional additives evenly to obtain a combined polyether component;

[0042] (2) Mix the polyether component and the polyisocyanate component, foam, and mold;

[0043] In some preferred embodiments, the foaming temperature for mixing the polyether component and the polyisocyanate component is 15-25°C.

[0044] The polyurethane rigid foam provided by this invention has stable gel time and core density, and a smooth and controllable foaming process, exhibiting good industrial applicability. More importantly, while maintaining a low thermal conductivity and a high oxygen index, the polyurethane foam still possesses improved compressive and flexural strength. Therefore, the foam simultaneously possesses the advantages of fine cell structure, high strength, and good flame retardancy, and can be widely used in the field of insulation material preparation, such as insulation layers for refrigerated containers and refrigerated trucks. Detailed Implementation

[0045] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0046] Unless otherwise specified, the raw material information in the following embodiments is derived from commercially available finished products. Among them:

[0047] Polyether polyol A1: 3-aminopropyltriethoxysilane and diphenylphosphine chloride were added dropwise at a molar ratio of 1:1, while triethylamine, in a molar amount equal to that of 3-aminopropyltriethoxysilane, was used to provide an alkaline environment for the reaction. The reaction was carried out at room temperature for two hours to obtain an intermediate. The intermediate and potassium hydroxide were mixed in a reactor, with the amount of potassium hydroxide being 1% of the mass of 3-aminopropyltriethoxysilane. The mixture was purged with nitrogen and evacuated, then stirred and heated to 120°C. Subsequently, a portion of propylene oxide (10% of the total mass of propylene oxide) was added, with the total molar amount of propylene oxide being 5 times the molar amount of 3-aminopropyltriethoxysilane. The mixture was allowed to mature for 2 hours. After maturation, the remaining propylene oxide was added and the temperature was raised to 150°C. The pressure was maintained at 0.8 MPa, and the polymerization reaction was carried out for 2 hours. The mixture was then allowed to mature under vacuum to remove light component impurities. After aging, phosphoric acid was added for neutralization, followed by the addition of magnesium silicate for adsorption and dehydration. After stirring and filtration, polyether polyol A1 was obtained; functionality 1, hydroxyl value 100 mg KOH / g, viscosity 600 mPa*s.

[0048] Polyether polyol A2: 3-aminopropyltriethoxysilane and phenylphosphine dichloride were added dropwise at a molar ratio of 1:1, while triethylamine, in a molar amount equal to that of 3-aminopropyltriethoxysilane, was used to provide an alkaline environment for the reaction. The reaction was carried out at room temperature for two hours to obtain an intermediate. The intermediate and DMC were mixed in a reactor, wherein the amount of DMC was 2% of the mass of 3-aminopropyltriethoxysilane. The reactor was purged with nitrogen and evacuated, then stirred and heated to 130°C. Subsequently, a portion of propylene oxide (10% of the total mass of propylene oxide) was added, with the total molar amount of propylene oxide being 8 times the molar amount of 3-aminopropyltriethoxysilane. The mixture was allowed to mature for 2 hours. After maturation, the remaining propylene oxide was added and the temperature was raised to 150°C. The pressure was maintained at 0.8 MPa, and the polymerization reaction was carried out for 2 hours. The mixture was then allowed to mature under vacuum to remove light component impurities. After aging, phosphoric acid was added for neutralization, followed by the addition of magnesium silicate for adsorption and dehydration. After stirring and filtration, polyether polyol A2 was obtained; functionality 1, hydroxyl value 75 mg KOH / g, viscosity 750 mPa*s.

[0049] Polyether polyol A3: (3-aminopropyl)dimethylmethoxysilane and diphenylphosphine chloride were added dropwise at a molar ratio of 2.5:1, while triethylamine, in a molar amount equal to that of (3-aminopropyl)dimethylmethoxysilane, was used to provide an alkaline environment for the reaction. The reaction was carried out at room temperature for two hours to obtain an intermediate. The intermediate and sodium hydroxide were mixed in a reactor, wherein the amount of sodium hydroxide was 3% of the mass of (3-aminopropyl)dimethylmethoxysilane. The reactor was purged with nitrogen and evacuated, then stirred and heated to 150°C. Subsequently, a portion of propylene oxide (10% of the total mass of propylene oxide) was added, with the total molar amount of propylene oxide being three times the molar amount of (3-aminopropyl)dimethylmethoxysilane. The mixture was allowed to mature for 2 hours. After maturation, the remaining propylene oxide was added and the temperature was raised to 180°C. The pressure was maintained at 0.8 MPa, and the polymerization reaction was carried out for 2 hours. The mixture was then allowed to mature under vacuum to remove light component impurities. After aging, phosphoric acid was added for neutralization, followed by the addition of magnesium silicate for adsorption and dehydration. After stirring and filtration, polyether polyol A3 was obtained; functionality 1, hydroxyl value 118 mg KOH / g, viscosity 420 mPa*s.

[0050] Polyether polyol B1: R2839, using sucrose as an initiator, has a hydroxyl value of 380 mg KOH / g, a functionality of 5.5, and a viscosity of 11000 mPa*s. Produced by Wanhua Chemical (Yantai) Rongwei.

[0051] Polyether polyol B2: R4110, using sucrose as an initiator, has a hydroxyl value of 440 mgKOH / g, a functionality of 4, and a viscosity of 3000 mPa*s. Produced by Wanhua Chemical (Yantai) Rongwei.

[0052] Polyether polyol C1: R2380, using sorbitol as an initiator, has a hydroxyl value of 480 mg KOH / g, a functionality of 5.4, and a viscosity of 25000 mPa*s. Produced by Wanhua Chemical (Yantai) Rongwei.

[0053] Polyether polyol C2: R6245, using sorbitol as an initiator, has a hydroxyl value of 450 mg KOH / g, a functionality of 5.4, and a viscosity of 23000 mPa*s. Produced by Wanhua Chemical (Yantai) Rongwei.

[0054] Polyether polyol D1: A210, using propylene glycol as an initiator, has a hydroxyl value of 110 mgKOH / g, a functionality of 2, and a viscosity of 250 mPa*s. Produced by Wanhua Chemical (Yantai) Rongwei.

[0055] Polyether polyol D2: C2004, using propylene glycol as an initiator, hydroxyl value 280 mgKOH / g, functionality 2, viscosity 80 mPa*s, Wanhua Chemical (Yantai) Rongwei

[0056] Polyester polyol E1: PS-2352, with phthalic anhydride as the initiator, functionality 2, hydroxyl value 235 mgKOH / g, viscosity 3500mp*s, Stephan

[0057] Polyester polyol E2: PS-3152, with phthalic anhydride as the initiator, functionality 2, hydroxyl value 315 mg KOH / g, viscosity 4200 mp*s, Stephan

[0058] TCPP Flame Retardant: Yake Technology

[0059] B8546 Silicone Oil: Evonik Specialty Chemicals (Shanghai) Co., Ltd.

[0060] Composite catalyst A: a mixture of pentamethyldiethylenetriamine, dimethylcyclohexylamine, and TMR-2 in a mass ratio of 1:5:1, produced by Evonik Specialty Chemicals (Shanghai) Co., Ltd.

[0061] Composite catalyst B: a mixture of dimethylaminoethyl ether, dimethylcyclohexylamine, and potassium acetate in a mass ratio of 1:10:2, manufactured by Evonik Specialty Chemicals (Shanghai) Co., Ltd.

[0062] Cyclopentane: Meilong Chemical

[0063] n-Pentane: Meilong Chemical

[0064] PM200: Wanhua Chemical

[0065]

Examples S1-S6

[0066] Prepare the raw materials according to the formula in Table 1, and mix them thoroughly after heating each material to 20℃. Pour the mixed material into a 35cm*35cm*10cm foaming mold for foaming at a mold temperature of 38℃ and a material density of 48kg / m³. 3 To prepare rigid polyurethane foam.

[0067] Table 1. Raw material formulations (g) in Examples S1-S6

[0068]

[0069]

[0070] Comparative Example D1

[0071] Polyurethane rigid foam was prepared by foaming according to the same formulation and method as in Example S1, except that polyether polyol A1 was not added and the amount of polyether polyol D1 was increased accordingly to ensure that the total mass of the combined polyether components remained unchanged.

[0072] Comparative Example D2

[0073] Polyurethane rigid foam was prepared by foaming according to a formula and method that is basically the same as that in Example S1, except that the polyether polyol A1 was replaced with the same mass of flame retardant polyol FR212 (Wanhua Chemical (Yantai) Rongwei Polyurethane Co., Ltd.).

[0074] The performance tests shown in Table 2 were performed on the polyurethane rigid foams prepared in Examples S1-S6 and Comparative Examples D1-D2. The test results are as follows. The relevant test methods mainly include:

[0075] (1) Gel time: Wanhua Chemical (Yantai) Rongwei Polyurethane Co., Ltd. Enterprise Standard Q / 0600YPU 026-2022

[0076] (2) Foam core density: Wanhua Chemical (Yantai) Rongwei Polyurethane Co., Ltd. Enterprise Standard Q / 0600YPU 026-2022

[0077] (3) Thermal conductivity: ASTM C518

[0078] (4) Oxygen index: GB / T 2406-009

[0079] (5) Compressive strength: GB / T 8813-2008

[0080] (6) Bending strength: GB / T 8812-2008

[0081] Table 2. Performance Test Results

[0082]

[0083] As can be seen from the performance test results of D2 and D1 in Table 2, the introduction of conventional flame-retardant polyether improves the oxygen index to a certain extent, but it will cause some damage to the foam strength. It is difficult to improve both at the same time, which cannot fully meet the requirements of refrigerated trucks, refrigerated containers and other transport carriers for high-strength support materials.

[0084] The test results of S1-S6 show that the oxygen index of the polyurethane rigid foam obtained by the present invention is not only significantly improved by more than 2% compared with D1, which significantly improves the flame retardancy of the foam, but also improves the compressive strength and flexural strength at the same time, solving the pain points of the industry. The obtained polyurethane rigid foam is particularly suitable for applications such as refrigerated trucks and refrigerated containers that have high requirements for both flame retardancy and foam strength.

[0085] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing flame-retardant rigid foam polyether polyol, characterized in that, Includes the following processes: Using silane compounds containing primary amino groups and phenyl phosphorus halides as raw materials, an intermediate is obtained by reacting under alkaline conditions; then, using this intermediate as an initiator, a polymerization reaction is carried out with an oxidized olefin in the presence of a polymerization catalyst to obtain a polyether polyol. The silane compound is selected from one or more of 3-aminopropyltriethoxysilane, (3-aminopropyl)dimethylmethoxysilane, and (3-aminoethyl)dimethylmethoxysilane; The phenyl phosphorus halide is selected from one or both of diphenyl phosphorus chloride and phenyl dichloride; The oxidized olefin is one or more of ethylene oxide, propylene oxide, butane oxide, and tetrahydrofuran.

2. The method for preparing flame-retardant rigid foam polyether polyol according to claim 1, characterized in that, The molar ratio of the silane compound and the phenyl phosphorus halide is 1-3:

1.

3. The method for preparing flame-retardant rigid foam polyether polyol according to claim 2, characterized in that, The alkaline conditions for the reaction of the silane compound and phenyl phosphorus halide are provided by an organic base; the organic base is selected from one or more of triethylamine, dimethylethylamine, diisopropylethylamine, sodium methoxide, potassium ethoxide, and potassium tert-butoxide. The amount of the organic base used, in molar terms, is 0.5-2 times the molar amount of the silane compound.

4. The method for preparing flame-retardant rigid foam polyether polyol according to any one of claims 1-3, characterized in that, The amount of the oxidized olefin is 2-8 times the molar amount of the corresponding silane compound.

5. The method for preparing flame-retardant rigid foam polyether polyol according to claim 4, characterized in that, The polymerization catalyst is an alkaline catalyst and / or a bimetallic complex catalyst.

6. The method for preparing flame-retardant rigid foam polyether polyol according to claim 5, characterized in that, The polymerization catalyst is one or more of potassium hydroxide, sodium hydroxide, potassium alkoxide, sodium alkoxide, MMC, and DMC.

7. The method for preparing flame-retardant rigid foam polyether polyol according to claim 4, characterized in that, The amount of the polymerization catalyst used is 1-3% of the mass of the corresponding silane compound.

8. The method for preparing flame-retardant rigid foam polyether polyol according to any one of claims 1-3, characterized in that, The reaction temperature of the silane compound and the phenyl phosphorus halide is 35-45℃, and the reaction time is 1-3 hours.

9. A flame-retardant rigid foam polyether polyol prepared by the method according to any one of claims 1-8, characterized in that, It has a functionality of 1, a hydroxyl value of 70-120 mg KOH / g, and a viscosity of 400-800 MPa·s at 25℃.

10. A flame-retardant rigid polyurethane foam, characterized in that, It includes a polyisocyanate component and a combined polyether component, said combined polyether component comprising A) a polyol, B) a foaming agent and optionally C) an additive; Wherein, A) the polyol includes the flame-retardant rigid foam polyether polyol prepared by the method of any one of claims 1-8.

11. The flame-retardant rigid polyurethane foam according to claim 10, characterized in that, The flame-retardant rigid foam polyether polyol has a mass content of 5-40 wt% in polyol A).

12. The flame-retardant rigid polyurethane foam according to claim 10, characterized in that, The mass ratio of the polyisocyanate component to the combined polyether component is (1-1.5):

1.

13. The flame-retardant rigid polyurethane foam according to claim 12, characterized in that, The polyisocyanate component is polymeric MDI or liquefied modified MDI.

14. The flame-retardant rigid polyurethane foam according to claim 13, characterized in that, The polyisocyanate component is one or more of Wanhua PM200, PM400, and PM700.

15. The flame-retardant rigid polyurethane foam according to claim 12, characterized in that, B) The amount of foaming agent used is 5-15% of the mass of the polyether components.

16. The flame-retardant rigid polyurethane foam according to claim 12, characterized in that, C) The amount of additives used is 10-20% of the mass of the polyether components.

17. The flame-retardant rigid polyurethane foam according to any one of claims 10-16, characterized in that, A) The polyol may optionally include at least one of the following: a polyether polyol starting with sucrose, a polyether polyol starting with sorbitol, a polyether polyol starting with propylene glycol, and a polyester polyol starting with phthalic anhydride.

18. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, Polyether polyols with sucrose as the initiator are polyether polyols produced by polymerization of sucrose with propylene oxide and / or ethylene oxide. They have a molecular weight of 300-800, a functionality of 4.5-6, and a hydroxyl value of 300-420 mgKOH / g.

19. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, The mass fraction of polyether polyols using sucrose as an initiator in polyol A) is ≤40wt%.

20. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, Polyether polyols with sorbitol as the initiator are polyether polyols produced by polymerization of propylene oxide and / or ethylene oxide with sorbitol as the initiator. They have a molecular weight of 600-700, a functionality of 4.5-6, and a hydroxyl value of 400-500 mgKOH / g.

21. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, The mass fraction of polyether polyols with sorbitol as the initiator in polyol A) is ≤30wt%.

22. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, Polyether polyols with propylene glycol as the initiator are polyether polyols produced by polymerizing propylene glycol with propylene oxide and / or ethylene oxide. They have a molecular weight of 400-1000, a functionality of 1.5-2, and a hydroxyl value of 400-800 mgKOH / g.

23. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, The mass fraction of polyether polyols using propylene glycol as an initiator in polyol A) is ≤30wt%.

24. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, Polyester polyols using phthalic anhydride as an initiator have a molecular weight of 300-500, a functionality of 2, and a hydroxyl value of 220-350 mgKOH / g.

25. The flame-retardant rigid polyurethane foam according to claim 17, characterized in that, The mass fraction of polyester polyols using phthalic anhydride as an initiator in polyol A) is ≤20wt%.

26. The flame-retardant rigid polyurethane foam according to any one of claims 10-16, characterized in that, The foaming agent is one or more of cyclopentane, isopentane, and n-pentane, or a mixture of at least one of cyclopentane, isopentane, and n-pentane and water.

27. The flame-retardant rigid polyurethane foam according to any one of claims 10-16, characterized in that, The additive is one or more of flame retardants, surfactants, and catalysts.

28. The flame-retardant rigid polyurethane foam according to claim 27, characterized in that, The flame retardant is tri(chloroisopropyl) phosphate and / or triethyl phosphate.

29. The flame-retardant rigid polyurethane foam according to claim 27, characterized in that, The surfactant is a siloxane.

30. The flame-retardant rigid polyurethane foam according to claim 27, characterized in that, The catalyst is an amine and / or a metal salt and / or water.

31. The flame-retardant rigid polyurethane foam according to claim 30, characterized in that, The catalyst is one or more of pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, triethylenediamine, TMR-2, N,N-dimethylbenzylamine, potassium formate, potassium acetate, potassium isooctanoate, and water.

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