Phosphate ester compound as well as preparation method and application thereof

Abstract

The invention discloses a phosphate ester compound as well as a preparation method and application thereof, and relates to the technical field of phosphorus compounds. The phosphate ester compound provided by the invention has a specific structure, excellent flame retardant property and good stability, and the hydroxyl contained in the structure can react with isocyanate, so that the phosphate ester compound can be embedded into a polyurethane chain segment in the preparation process of rigid polyurethane foam, is suitable for being used as a flame retardant, and can be used for preparing rigid polyurethane foam. Particularly, the flame retardant of the rigid polyurethane foam material is used, so that the flame retardant is difficult to separate out in the rigid polyurethane foam material, and the obtained rigid polyurethane foam not only has excellent flame retardant property, but also has good stability.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphorus compounds, and in particular to a phosphate compound and a preparation method and application thereof. Background Art

[0002] Rigid polyurethane foam is referred to as rigid polyurethane foam (RPUF) for short. It has a series of advantages such as low density, high strength, low thermal conductivity, strong bonding performance, low water absorption, excellent sound absorption and shock resistance, and convenient construction. Therefore, it is widely used in various fields of the national economy as a thermal insulation, structural or decorative material, such as building energy conservation, transportation, petrochemical pipelines, refrigerators and freezers, refrigerated warehouses, automotive insulation, aviation and military, furniture manufacturing and other industries. However, rigid polyurethane foam is a flammable material with an oxygen index of only 17% to 18%. This is because polyurethane foam contains a large number of flammable molecular segments and its high specific surface area, which makes rigid polyurethane foam that has not been flame-retardant treated very easy to burn, and releases a large amount of HCN and NO during the combustion process. 2 And toxic and harmful gases such as CO, posing a huge fire hazard.

[0003] Flame retardants can turn flammable rigid polyurethane foam materials into flame-retardant materials, play a role in delaying combustion and suppressing smoke, thereby reducing the possibility of fire, reducing the degree of fire damage, and making rigid polyurethane foam products safer. Common flame retardants in rigid polyurethane foam are as follows: inorganic flame retardants, such as aluminum hydroxide, magnesium hydroxide, red phosphorus, ammonium polyphosphate, aluminum hypophosphite, montmorillonite, etc.; halogen flame retardants, such as TCPP, TCEP, TDCP, etc.; organic phosphorus flame retardants, such as dimethyl methyl phosphate DMMP, pentaerythritol caged phosphate PEPA, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, phosphazene, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO and its derivatives. However, inorganic flame retardants have the disadvantages of poor compatibility and easy precipitation, while halogen flame retardants do not conform to the concept of environmental protection development. Phosphorus-based flame retardants are the mainstream development direction in the industry, but simple phosphates (such as dimethyl methyl phosphate, trimethyl phosphate, triphenyl phosphate, triethyl phosphate, etc.) will not react and synthesize into polyurethane segments, and there is a problem of easy precipitation. Complex phosphates, such as phosphazenes, DOPO and their derivatives, have the disadvantages of high cost and difficulty in large-scale application. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the object of the present invention is to provide a phosphate compound which has excellent flame retardant effect as a flame retardant and contains a hydroxyl group in its structure, which can react with isocyanate and be embedded in the polyurethane chain segment and is not easy to precipitate.

[0005] The second aspect of the present invention is to provide a method for preparing a phosphate ester compound.

[0006] The third aspect of the present invention is to provide a flame retardant.

[0007] The fourth aspect of the present invention is to provide a rigid polyurethane foam.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] The first aspect of the present invention provides a phosphate ester compound, and the phosphate ester compound has a structure shown in the following formula (Ⅰ):

[0010]

[0011] In formula (Ⅰ), R1 and R2 are independently selected from x is an integer from 2 to 6, and m is 1 or 2;

[0012] A is selected from Na, K, Zn, Mg, Ca, Cu, Al, Fe, +NH 4 , +NH 3 -CH 2 -CH 2 -NH 2 , +NH 3 -CH 2 -CH 2 -CH 2 OH,

[0013] n is an integer from 1 to 3.

[0014] The phosphate ester compound of the present invention has a specific structure and a relatively simple structure. At the same time, the structure of the phosphate ester compound contains two hydroxyl groups, which can react with isocyanate and be embedded in the polyurethane chain segment. As a flame retardant, especially as a flame retardant for rigid polyurethane foam, it has excellent flame retardant performance. Compared with additive flame retardants, the flame retardant of the present invention is more resistant to precipitation in polyurethane foam and can maintain the flame retardant effect for a longer time.

[0015] In some embodiments of the present invention, the hydroxyl value of the phosphate ester compound is 200 - 700 mgKOH / g.

[0016] In some examples of the present invention, the hydroxyl value of the phosphate ester compound is 200 - 400 mgKOH / g.

[0017] In some embodiments of the present invention, the acid value of the phosphate ester compound < 1 mgKOH / g.

[0018] In some embodiments of the present invention, the acid value of the phosphate compound is 0.1-0.9 mgKOH / g.

[0019] In some specific embodiments of the present invention, the acid value of the phosphate compound is 0..5-0.9 mgKOH / g.

[0020] In some embodiments of the present invention, the water content of the phosphate compound is less than 0.5%.

[0021] When used as a flame retardant for rigid polyurethane foam materials, the hydroxyl value, acid value and moisture content of phosphate compounds will affect the severity of the reaction during the rigid polyurethane foaming process and the quality of the rigid polyurethane foam.

[0022] The second aspect of the present invention provides a method for preparing the phosphate compound according to the first aspect of the present invention, comprising the following steps:

[0023] Phosphorus pentoxide and polyol are mixed to react to obtain a first product; the first product is mixed with a catalyst to obtain a second product after an esterification reaction; the second product is neutralized with an alkaline substance and distilled to obtain the phosphate compound.

[0024] In the preparation method of the present invention, phosphorus pentoxide reacts with a polyol to obtain a mixture of phosphate monoesters and phosphate diesters, i.e., a first product. After adding a catalyst, an esterification reaction occurs to convert the phosphate monoester in the first product into a phosphate diester, wherein the catalyst plays a role in catalyzing the esterification reaction.

[0025] The second product is neutralized with an alkaline substance, wherein the amount of the alkaline substance used is related to the acid value of the second product, and finally a phosphate compound with the acid value required by the present invention is obtained. The main function of the alkaline substance is to adjust the acid value of the phosphate compound. The distillation process is to reduce the residual water and remove the unreacted polyol in the system.

[0026] In some embodiments of the present invention, the reaction of phosphorus pentoxide and polyol is carried out under an inert atmosphere.

[0027] In some embodiments of the present invention, the inert atmosphere comprises nitrogen.

[0028] In some embodiments of the present invention, the temperature of the reaction of phosphorus pentoxide and polyol is 0-5°C.

[0029] In some embodiments of the present invention, an ice water bath is used to achieve a reaction temperature of 0-5°C.

[0030] Phosphorus pentoxide has a strong dehydrating property. Too high a reaction temperature will cause dehydration and carbonization of the polyol, resulting in the appearance of black impurities in the first product and a darker color of the product.

[0031] In some embodiments of the present invention, the temperature of the reaction of the first product with the catalyst is 90-130°C.

[0032] In some embodiments of the present invention, the temperature of the reaction of the first product with the catalyst is 100-120°C.

[0033] Heating is beneficial to promoting the esterification reaction rate and shortening the esterification reaction time.

[0034] In some embodiments of the present invention, the reaction time of the first product and the catalyst is 1 to 3 hours.

[0035] In some embodiments of the present invention, the reaction time of the first product and the catalyst is 1.5 to 2.5 hours.

[0036] In some embodiments of the present invention, the temperature of distillation of the second product and the alkaline substance is 90-130°C.

[0037] In some embodiments of the present invention, the temperature of distillation of the second product and the alkaline substance is 100-120°C

[0038] In some embodiments of the present invention, the vacuum degree of the distillation of the second product and the alkaline substance is -0.05 to -0.1 MPa.

[0039] In some embodiments of the present invention, the molar ratio of phosphorus pentoxide to polyol is 1:(3-6).

[0040] In some embodiments of the present invention, the molar ratio of phosphorus pentoxide to polyol is 1:(4-5).

[0041] In some embodiments of the present invention, the amount of the catalyst used is 0.1 to 10% of the mass of the first product.

[0042] In some embodiments of the present invention, the amount of the catalyst used is 0.5-1% of the mass of the first product.

[0043] In some embodiments of the present invention, the polyol includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerol, 1,4-butylene glycol, 1,5-pentanediol, and 1,6-hexanediol.

[0044] In some embodiments of the present invention, the catalyst includes at least one of concentrated sulfuric acid, concentrated phosphoric acid, heteropoly acid, zinc dichloride, aluminum chloride, ferric chloride, titanium tetrachloride, tin tetrachloride, antimony pentachloride, boron trifluoride, aluminum oxide, aluminum oxide-silicon dioxide, cadmium sulfide, zinc sulfide, zeolite molecular sieve, and ion exchange resin.

[0045] In some embodiments of the present invention, the alkaline substance includes at least one of a solid base, an alkaline solution, a metal oxide, and an amine compound.

[0046] In some embodiments of the present invention, the solid base includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate.

[0047] In some embodiments of the present invention, the alkali solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, and ammonia water.

[0048] In some embodiments of the present invention, the metal oxide includes at least one of zinc oxide, magnesium oxide, calcium oxide, copper oxide, cuprous oxide, aluminum oxide, and iron oxide.

[0049] In some embodiments of the present invention, the amine compound includes at least one of triethylamine, ethylenediamine, ethanolamine, diethanolamine, and triethanolamine.

[0050] In the preparation method of the present invention, the structure of the alkaline substance is related to that of the phosphate compound. When the alkaline substance is a metal oxide, A of the structure shown in formula (I) of the phosphate compound is selected from Na, K, Zn, Mg, Ca, Cu, Al or Fe; when the alkaline substance is a solid base, an alkali solution or an amine compound, A is selected from + NH 4 , + NH 3 -CH 2 -CH 2 -NH 2 , + NH 3 -CH 2 -CH 2 -CH 2 OH,

[0051] In some embodiments of the present invention, the amount of the alkaline substance is 8-75% of the mass of the second product.

[0052] In some embodiments of the present invention, the amount of the alkaline substance is 8-35% of the mass of the second product.

[0053] In the preparation method of the phosphate ester compound of the present invention, by adjusting the type of polyol, phosphate ester compounds with different hydroxyl values ​​can be obtained, which can be used as flame retardants to meet the requirements of different rigid polyurethane foaming. The acid value and water content of the phosphate ester compound can be adjusted by alkali neutralization and distillation.

[0054] The third aspect of the present invention provides a flame retardant, comprising the phosphate compound described in the first aspect of the present invention, or the phosphate compound prepared by the preparation method described in the second aspect of the present invention.

[0055] The fourth aspect of the present invention provides a rigid polyurethane foam material, wherein the raw materials for preparing the rigid polyurethane foam material include the phosphate ester compound described in the first aspect of the present invention, or the phosphate ester compound prepared by the preparation method described in the second aspect of the present invention, or the flame retardant described in the third aspect of the present invention.

[0056] In some embodiments of the present invention, the mass content of the flame retardant formed by the phosphate compound in the raw materials for preparing the rigid polyurethane foam material is 4-6%.

[0057] In some embodiments of the present invention, the raw materials for preparing the rigid polyurethane foam material include, by weight, 90 to 110 parts of polyether polyol, 10 to 20 parts of flame retardant, 1 to 5 parts of catalyst, 1 to 5 parts of accelerator, 1 to 5 parts of foam stabilizer, 160 to 165 parts of curing agent, and 1 to 10 parts of water.

[0058] In some embodiments of the present invention, the flame retardant is the flame retardant described in the third aspect of the present invention.

[0059] In some embodiments of the present invention, the catalyst and accelerator are polyurethane catalysts and polyurethane accelerators; the curing agent is polymethylene polyphenyl polyisocyanate.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] The invention provides a phosphate compound. The phosphate compound has a specific structure, excellent flame retardant performance and stability, and the hydroxyl contained in the structure can react with isocyanate, so the phosphate compound can be embedded in a polyurethane segment during the preparation of a rigid polyurethane foam, thereby overcoming the disadvantages of poor compatibility of existing flame retardants with the rigid polyurethane foam system or easy precipitation. The phosphate compound is suitable for use as a flame retardant, especially a flame retardant for a rigid polyurethane foam material, and is not easy to precipitate in the rigid polyurethane foam material. The obtained rigid polyurethane foam has not only excellent flame retardant performance but also good stability, the flame retardant grade reaches UL-94HF-1 level, and the oxygen index does not exceed 25. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is the infrared spectrum of the phosphate compound of Example 1 of the present invention.

[0063] Figure 2 This is the infrared spectrum of the phosphate compound of Example 2 of the present invention.

[0064] Figure 3 This is the infrared spectrum of the phosphate compound of Example 3 of the present invention.

[0065] Figure 4 This is the infrared spectrum of the phosphate compound of Example 4 of the present invention.

[0066] Figure 5 This is the infrared spectrum of the phosphate compound of Example 5 of the present invention. DETAILED DESCRIPTION

[0067] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0068] The following describes it in detail with reference to specific embodiments.

[0069] Example 1

[0070] This embodiment provides a phosphate compound, the structure of which is shown in formula (1):

[0071]

[0072] The preparation method comprises the following steps:

[0073] Under nitrogen protection and ice-water bath cooling at 0-5°C, 1 mol of phosphorus pentoxide was added to 4 mol of ethylene glycol in three portions to obtain the first product;

[0074] Take 100g of the first product, add 1.0g of concentrated phosphoric acid with a mass fraction of 85% as a catalyst, heat to 120°C, react for 2 hours, and obtain the second product;

[0075] Take 100g of the second product, add 22.1g of zinc oxide, raise the temperature to 100°C, and distill for 2 hours at a vacuum degree of -0..1MPa to obtain a phosphate compound.

[0076] The phosphate compound of the present embodiment is a light yellow transparent liquid. According to GB / T 12008.5-2010, Karl Fischer method and GB / T 12008.3-2009, the acid value is 0.87 mgKOH / g, the water content is 0.40%, and the hydroxyl value is 250 mgKOH / g.

[0077] The infrared spectrum of the phosphate compound is as follows Figure 1 As shown, 3359.08cm -1 -OH stretching vibration absorption peak, 2952.90cm -1 -CH 2 -Stretching vibration absorption peak, 1649.76cm -1 and 1456.78cm -1 It is the PO absorption peak.

[0078] Example 2

[0079] This embodiment provides a phosphate compound, the structure of which is shown in formula (2):

[0080]

[0081] The preparation method comprises the following steps:

[0082] Under nitrogen protection and ice-water bath cooling at 0-5°C, 1 mol of phosphorus pentoxide was added to 4 mol of ethylene glycol in three portions to obtain the first product;

[0083] Take 100g of the first product, add 2g of aluminum chloride as a catalyst, raise the temperature to 100°C, react for 1 hour, and obtain the second product;

[0084] Take 100 g of the second product, add 21.2 g of sodium hydroxide solid, raise the temperature to 100° C., and distill for 3 hours at a vacuum degree of -0.1 MPa to obtain a phosphate ester compound.

[0085] The phosphate compound of the present embodiment is a light yellow transparent liquid. According to GB / T 12008.5-2010, Karl Fischer method and GB / T 12008.3-2009, the acid value is 0.55 mgKOH / g, the water content is 0.36%, and the hydroxyl value is 255 mgKOH / g.

[0086] The infrared spectrum of the phosphate compound is as follows Figure 2 , of which 3417.40cm -1 -OH absorption peak, 2950.46cm -1 、2883.13cm -1 -CH 2 -Stretching vibration absorption peak, 1644.01cm -1and 1459.39cm -1 It is the PO absorption peak.

[0087] Example 3

[0088] This embodiment provides a phosphate compound, the structure of which is shown in formula (3):

[0089]

[0090] The preparation method comprises the following steps:

[0091] Under nitrogen protection and ice-water bath cooling at 0-5°C, 1 mol of phosphorus pentoxide was added to 4 mol of ethylene glycol in three portions to obtain the first product;

[0092] Take 100g of the first product, add 10g of zeolite molecular sieve as a catalyst, heat to 110°C, react for 2.5 hours, and obtain the second product;

[0093] Take 100g of the second product, add 72g of 30% by mass sodium hydroxide solution, heat to 100°C, and distill for 3 hours at a vacuum degree of -0.08MPa to obtain a phosphate compound.

[0094] The phosphate compound of the present embodiment is a light yellow transparent liquid. According to GB / T 12008.5-2010, Karl Fischer method and GB / T 12008.3-2009, the acid value is 0.37 mgKOH / g, the water content is 0.50%, and the hydroxyl value is 250 mgKOH / g.

[0095] The infrared spectrum of the phosphate compound of this embodiment is as follows Figure 3 As shown, 3373.94cm -1 -OH absorption peak, 2953.63 cm -1 -CH 2 -Stretching vibration absorption peak, 1651.00cm -1 and 1456.67cm -1 It is the PO absorption peak.

[0096] Example 4

[0097] This embodiment provides a phosphate compound, the structure of which is shown in formula (4):

[0098]

[0099] The preparation method comprises the following steps:

[0100] Under nitrogen protection and ice-water bath cooling at 0-5°C, 1 mol of phosphorus pentoxide was added to 4 mol of ethylene glycol in three portions to obtain the first product;

[0101] Take 100g of the first product, add 10g of ion exchange resin as a catalyst, raise the temperature to 120°C, react for 2 hours, and obtain the second product;

[0102] Take 100 g of the second product, add 34 g of triethylamine, raise the temperature to 100° C., and distill for 2 hours at a vacuum degree of -0.01 MPa to obtain a phosphate ester compound.

[0103] The phosphate compound of the present embodiment is a light yellow transparent liquid. According to GB / T 12008.5-2010, Karl Fischer method and GB / T 12008.3-2009, the acid value is 0.58 mgKOH / g, the water content is 0.22%, and the hydroxyl value is 270 mgKOH / g.

[0104] The infrared spectrum of the phosphate compound of this embodiment is as follows Figure 4 As shown, 3377.84cm -1 -OH absorption peak, 2957.75 cm -1 -CH 3 、-CH 2 -Stretching vibration absorption peak, 1680.48cm -1 and 1455.27cm -1 It is the PO absorption peak.

[0105] Example 5

[0106] This embodiment provides a phosphate compound, the structure of which is shown in formula (5):

[0107]

[0108] The preparation method comprises the following steps:

[0109] Under nitrogen protection and ice-water bath cooling at 0-5°C, 1 mol of phosphorus pentoxide was added to 5 mol of diethylene glycol in three portions to obtain the first product;

[0110] Take 100g of the first product, add 0.5g of 98% concentrated sulfuric acid as a catalyst, heat to 110°C, react for 3 hours, and obtain the second product;

[0111] Take 100 g of the second product, add 8.4 g of magnesium oxide, raise the temperature to 100° C., and distill for 2 hours at a vacuum degree of -0.1 MPa to obtain a phosphate compound.

[0112] The phosphate compound of the present embodiment is a light yellow transparent liquid. According to GB / T 12008.5-2010, Karl Fischer method and GB / T 12008.3-2009, the acid value is 0.89 mgKOH / g, the water content is 0.25%, and the hydroxyl value is 370 mgKOH / g.

[0113] The infrared spectrum of the phosphate compound of this embodiment is as follows Figure 5 As shown, 3411.19cm -1 -OH absorption peak, 3060.82cm -1 、2959.32cm -1 、2884.11cm -1 -CH 2 -Stretching vibration absorption peak, 1643..06cm -1 and 1439.59cm -1 It is the PO absorption peak.

[0114] Application Examples

[0115] The phosphate compounds prepared in Examples 1 to 5 were used as flame retardants to prepare rigid polyurethane foams. The specific formulas were as follows, calculated by weight:

[0116] Polyether polyol 4110: 100 parts, polyurethane catalyst A33: 3 parts, polyurethane accelerator DMP30: 3 parts, foam stabilizer AK8805: 3 parts, water: 4 parts, flame retardant: 15 parts, polymethylene polyphenyl polyisocyanate PAPI: 163 parts.

[0117] The preparation method of the rigid polyurethane foam comprises the following steps:

[0118] A polyurethane catalyst A33, a polyurethane accelerator DMP30, a foam stabilizer AK8805, water and a flame retardant are mixed with polyether polyol 4110 to obtain a polyether polyol mixture, and polymethylene polyphenyl polyisocyanate PAPI is added under stirring. After stirring until slight bubbles are formed, the mixture is introduced into a mold, and after complete foaming, a rigid polyurethane foam is obtained.

[0119] Results

[0120] The performance of the rigid polyurethane foam prepared using the phosphate compounds of Examples 1 to 5 as flame retardants was tested, and the test method was as follows:

[0121] According to the UL 94HBF test standard, a rigid polyurethane foam sample with a length × width × thickness = 150±5mm × 50±1mm × 13±0.5mm was taken for flame retardancy test; in addition, a rigid polyurethane foam sample with a length × width × thickness = 90mm × 10±0.5mm × 10±0.5mm was taken for oxygen index determination according to GB / T 2406.2-2009.

[0122] The test results are shown in Table 1 below.

[0123] Table 1 Flame retardant properties of rigid polyurethane foam obtained by using phosphate compounds as flame retardants in the examples

[0124]

[0125] As can be seen from Table 1, the phosphate compound obtained by the present invention is used as a flame retardant for rigid polyurethane foam. Since the phosphate compound contains a hydroxyl group in its structure, it can react with isocyanate and be embedded in the polyurethane chain segment, and is not prone to precipitation problems. Therefore, the rigid polyurethane foam obtained has excellent flame retardant properties, the flame retardant grade reaches UL-94HF-1, and the oxygen index does not exceed 25.

[0126] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A phosphate compound, characterized in that: The phosphate compound has a structure shown in the following formula (I): In formula (I), R1 and R2 are independently selected from x is 2 to 6 and x is an integer, and m is 1 or 2; A is selected from Na, K, Zn, Mg, Ca, Cu, Al, Fe, +NH4, + NH3-CH2-CH2-NH2, + NH3-CH2-CH2-CH2OH n is 1 to 3 and is an integer.

2. The phosphate compound according to claim 1, characterized in that The phosphate compound has a hydroxyl value of 200 to 700 mgKOH / g; And / or, the acid value of the phosphate compound is less than 1 mgKOH / g.

3. A method for preparing a phosphate compound according to claim 1 or 2, characterized in that: The steps include: Phosphorus pentoxide and polyol are mixed to react to obtain a first product; the first product is mixed with a catalyst to obtain a second product after an esterification reaction; the second product is neutralized with an alkaline substance and distilled to obtain the phosphate compound.

4. The preparation method according to claim 3, characterized in that: The reaction of phosphorus pentoxide and polyol is carried out under an inert atmosphere; And / or, the temperature of the reaction of phosphorus pentoxide and polyol is 0-5°C.

5. The preparation method according to claim 3, characterized in that: The temperature of the reaction between the first product and the catalyst is 90 to 130° C.; And / or, the reaction time of the first product and the catalyst is 1 to 3 hours.

6. The preparation method according to claim 3, characterized in that: The temperature of distillation of the second product and the alkaline substance is 90-130° C.; And / or, the vacuum degree of the distillation of the second product and the alkaline substance is -0.05 to -0.1 MPa.

7. The preparation method according to claim 3, characterized in that: The molar ratio of phosphorus pentoxide to polyol is 1:(3-6); And / or, the amount of the catalyst used is 0.1-10% of the mass of the first product.

8. The preparation method according to claim 3 or 7, characterized in that: The polyol includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerol, 1,4-butylene glycol, 1,5-pentanediol, and 1,6-hexanediol; and / or, the catalyst comprises at least one of concentrated sulfuric acid, concentrated phosphoric acid, heteropoly acid, zinc dichloride, aluminum trichloride, ferric chloride, titanium tetrachloride, tin tetrachloride, antimony pentachloride, boron trifluoride, aluminum oxide, aluminum oxide-silicon dioxide, cadmium sulfide, zinc sulfide, zeolite molecular sieve, and ion exchange resin; And / or, the alkaline substance includes at least one of a solid base, an alkaline solution, a metal oxide, and an amine compound.

9. A flame retardant, characterized in that: It includes the phosphate ester compound described in any one of claims 1 to 2, or the phosphate ester compound prepared by the preparation method described in any one of claims 3 to 8.

10. A rigid polyurethane foam material, characterized in that: The raw materials for preparing the rigid polyurethane foam material include the phosphate compound described in any one of claims 1 to 2, or the phosphate compound prepared by the preparation method described in any one of claims 3 to 8, or the flame retardant described in claim 9.

Images