A bio-based phosphorus-containing polyester polyol, and a preparation method and application thereof

Abstract

The application discloses a kind of bio-based phosphorus-containing polyester polyols and its preparation method and application, are made by component with mole percentage: polyol 60-75% and polybasic acid 25-40%;The polyol is low molecular polyol with at least three reactive hydroxyl groups;The polybasic acid is low molecular bio-based polybasic acid with at least two reactive carboxylic acid groups;Wherein polyol and polyol one component contain phosphorus element.The bio-based polyester polyol prepared by the application contains a large amount of phosphorus element and carbon element, has excellent condensed phase flame retardant effect.Compared with traditional flame retardant, there is no toxic gas such as chlorine gas, avoid the case of secondary injury while flame retardant;Test shows that the heat release of rigid polyurethane foam prepared by the polyol is greatly reduced, and the residual carbon after combustion is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of flame-retardant thermal insulation materials, specifically to a bio-based phosphorus-containing polyester polyol for preparing flame-retardant polyurethane foam, its preparation method, and its application. Background Technology

[0002] Polyurethane is one of the most widely used polymer materials in the world, with a global annual consumption exceeding 3.5 million tons. Its production is renowned for its low energy consumption, and its excellent thermal insulation, oil resistance, cold resistance, moisture resistance, and dimensional stability make it an indispensable material for shock absorption, padding, and thermal insulation, widely used in the automotive and home appliance industries. Other industries utilize polyurethane as a thermal insulation material, such as the thermal insulation filling layer of aerospace vehicles and the insulation and covering layers of rocket engines. However, unlike metals and inorganic non-metallic materials, most organic polymers are flammable and combustible. During combustion, they have a high heat release rate, high calorific value, and rapid flame propagation, making them difficult to extinguish. Combustion is often accompanied by smoke and molten dripping, leading to frequent major fire accidents causing huge economic losses and casualties. These accidents have exposed problems with the flame-retardant properties of electrical products; therefore, endowing polymer materials with flame-retardant properties is the most important way to solve the problem of fire accidents caused by polymers. However, the traditional flame retardant industry faces challenges such as poor compatibility, significant impact on mechanical properties, and the release of large amounts of toxic gases while providing flame retardancy. Therefore, the polyurethane insulation material market urgently needs a new type of green, efficient, and environmentally friendly flame retardant material. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of polyurethane in the prior art, which is severely flammable, by providing a bio-based phosphorus-containing flame-retardant polyester polyol. This polyol is characterized by high efficiency, durability, greenness, environmental friendliness, and pollution-free properties. Compared with traditional additive flame retardants, it is a reactive flame retardant with advantages such as high flame retardant efficiency, low mechanical loss of materials, no leakage of flame retardant, and high efficiency and durability.

[0004] The second objective of this invention is to provide a method for preparing the bio-based phosphorus-containing flame-retardant polyester polyol, which has the advantages of simple preparation process and high yield.

[0005] The third objective of this invention is to provide the application of the bio-based phosphorus-containing flame-retardant polyester polyol in flame-retardant polyurethane foam, which has the advantages of high flame-retardant efficiency, low mechanical loss of materials, no leakage of flame retardant and high efficiency and durability.

[0006] The objective of this invention is achieved through the following technical solution: a bio-based phosphorus-containing flame-retardant polyester polyol, made from components in molar percentages:

[0007] Polyols 60-75%

[0008] Polybasic acids 25-40%

[0009] The polyol is a low-molecular-weight polyol having at least three reactive hydroxyl groups (-OH), and the molecular weight of the low-molecular-weight polyol is between 100 and 200.

[0010] The polyol is a low-molecular-weight bio-based polyacid with at least two carboxylic acid groups (-COOH) that can participate in the reaction, and the molecular weight of the low-molecular-weight bio-based polyacid is 500-700.

[0011] The polyol and one of its components contain phosphorus.

[0012] The polyol may be tris(hydroxymethyl)phosphine oxide ((CH2OH)3PO) and / or diethanolamine.

[0013] The polyacid can be phytic acid (inositol hexaphosphate) and / or succinic acid.

[0014] The preparation method of the bio-based phosphorus-containing polyester polyol includes the following steps:

[0015] (1) Weigh out the polyol and add it to a container, which can be a three-necked flask equipped with an oil bath. Adjust the temperature to the condensation reaction temperature of 40-80℃ and preheat for 0.5-1h.

[0016] (2) Weigh out the polyacid and add it dropwise to the preheated polyol using a peristaltic pump at a rate of 6-8 rpm.

[0017] (3) React at a constant temperature of 40-80℃ for 1-3 hours;

[0018] (4) Raise the temperature to 100-130℃ and react at a constant temperature for 1-2 hours;

[0019] (5) Introduce nitrogen gas to remove water and volatile small molecules produced by the side reaction by purging with nitrogen gas. The nitrogen gas flow rate is 15-30 ml / min and the purging time is 3-5 h.

[0020] The bio-based phosphorus-containing polyols obtained by the above reaction have a functionality between 30 and 40.

[0021] The bio-based phosphorus-containing polyols obtained by the above reaction have a number-average molecular weight between 25,000 and 30,000, and a molecular weight distribution between 1 and 1.3.

[0022] The hydroxyl value of the bio-based phosphorus-containing polyols obtained by the above reaction is between 150 and 200.

[0023] Preferably, in step (2), the polybasic acid should be added dropwise into the container within 0.5 hours.

[0024] Preferably, the condensation reaction temperature in step (3) should be 60°C.

[0025] Preferably, the preparation method of the bio-based phosphorus-containing polyester polyol comprises the following steps: weighing polyol and polyacid in a molar ratio of 3:1 to 3:2; first, adding the polyol to a container and preheating it at 60°C for 0.5 h; then, adding the polyacid dropwise over 0.5 h, maintaining the temperature at 60°C, and performing a constant-temperature reverse condensation reaction for 2 h; then raising the temperature to 110 to 120°C, introducing nitrogen gas at a rate of 20 mL / min to remove volatile water and small molecule products; and finally, reacting for 4-6 h.

[0026] The bio-based phosphorus-containing flame-retardant polyester polyol described in this invention, as a flame retardant, employs a reactive flame-retardant approach compared to existing traditional flame retardants. This approach introduces flame-retardant elements into the polymer chain segments, minimizing the impact on the material's mechanical properties and avoiding the degradation of flame-retardant effects that occurs with traditional additive flame retardants as the material ages. Furthermore, the bio-based phosphorus-containing flame-retardant polyester polyol of this invention has a high phosphorus and carbon content, resulting in a significant condensed phase flame-retardant effect throughout the system. This truly achieves high flame-retardant efficiency, greenness, low smoke, and environmental friendliness, making it suitable for broad market applications.

[0027] The bio-based phosphorus-containing flame-retardant polyester polyol prepared in this invention is specifically used to prepare flame-retardant rigid polyurethane foam. The addition amount is 10-40 parts by weight, which endows rigid polyurethane foam with high flame retardant efficiency, green, low smoke and environmental protection effects.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] (1) Bio-based raw materials are used, which are widely derived from agricultural by-products such as soybeans and straw. They are not only greener and more environmentally friendly, but also cheaper and more readily available.

[0030] (2) The prepared bio-based phosphorus-containing flame-retardant polyester contains phosphorus, a highly efficient flame-retardant element, which is more environmentally friendly and efficient than traditional halogen flame-retardant elements and does not produce toxic gases when burning.

[0031] (3) The prepared bio-based phosphorus-containing flame-retardant polyester has a high carbon content and obvious condensed phase flame-retardant effect. The solid carbon layer generated when the flame retardant is in action can not only protect the substrate from air, but also inhibit the generation of smoke. Attached Figure Description

[0032] Figure 1 Fourier transform infrared spectrum of bio-based phosphorus-containing polyols;

[0033] Figure 2Photograph of the bio-based phosphorus-containing polyol prepared in Example 7;

[0034] Figure 3 Photograph of a rigid polyurethane foam sample prepared from bio-based phosphorus-containing polyols;

[0035] Figure 4 The heat release curves for the rigid polyurethane foam examples in Table 1 are shown below (where ■ represents rigid foam without added phosphorus-containing polyols, and ● represents rigid foam with 10% added phosphorus-containing polyols). Rigid foam with 20% phosphorus-containing polyols added. Rigid foam with 30% phosphorus-containing polyols added; ◆ Rigid foam with 40% phosphorus-containing polyols added.

[0036] Figure 5 The graph shows the limiting oxygen index data obtained after testing the rigid polyurethane foam in the example in Table 1.

[0037] Figure 6 The macroscopic morphology of the rigid polyurethane foam samples in Table 1 after vertical burning tests is shown (the amount of phosphorus-containing polyester polyol added in a, b, c, and d are 10 parts, 20 parts, 30 parts, and 40 parts, respectively).

[0038] Figure 7 The macroscopic morphology of residual carbon after cone calorimetry testing of the rigid polyurethane foams in Table 1 (a) without the addition of the phosphorus-containing polyester polyol of the present invention; b, c, d, and e) with the addition amounts of phosphorus-containing polyester polyol being 10 parts, 20 parts, 30 parts, and 40 parts, respectively.

[0039] Figure 8 The microstructure of residual carbon after cone calorimetry testing of the rigid polyurethane foams in Table 1 (a) without the addition of the phosphorus-containing polyester polyol of the present invention; b, c, d, and e with the addition amounts of phosphorus-containing polyester polyol being 10%, 20%, 30%, and 40%, respectively, magnified). Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0041] Components Example 1 Example 2 Example 3 polyols 60％ 67％ 75％ polyacids 40％ 33％ 25％

[0042] The preparation method of the bio-based phosphorus-containing polyester polyol in the above embodiments includes the following steps:

[0043] (1) Weigh out the polyol and add it to the container. Adjust the temperature to the condensation reaction temperature of 60℃ and preheat for 0.5h.

[0044] (2) Weigh out the polyacid and add it dropwise to the preheated polyol over 0.5 hours using a peristaltic pump at a rate of 7 rpm.

[0045] (3) The reaction was carried out at a constant temperature of 60℃ for 1.5 hours;

[0046] (4) Raise the temperature to 115℃ and keep it at a constant temperature for 1.2 hours;

[0047] (5) Introduce nitrogen gas to remove water and volatile small molecules produced by the side reaction by purging with nitrogen gas. The nitrogen gas flow rate is 20 ml / min and the purging time is 4 h.

[0048] Example 4

[0049] A method for preparing a bio-based phosphorus-containing polyester polyol, the specific preparation steps of which are as follows:

[0050] Accurately weigh 2.5 mol of tris(hydroxymethyl)phosphorus oxide and add it to a three-necked flask equipped with an oil bath. Set the oil bath to 60°C and preheat it at a constant temperature for 1 hour.

[0051] After preheating, accurately weigh 1 mol of phytic acid and use a peristaltic pump to gradually add the phytic acid dropwise into a three-necked flask containing polyol at a dropping rate of 6 rpm. It is expected that all the phytic acid will be added into the three-necked flask within 0.5 hours.

[0052] After the addition is complete, the reaction is kept at 60°C for 1.5 hours. At this time, the product in the three-necked flask should be a low molecular weight oligomer.

[0053] After the reaction is complete, the temperature of the oil bath is raised to 110°C and kept at this temperature for 2 hours.

[0054] After the reaction is complete, nitrogen gas is introduced into the entire system to remove volatile small molecules and water by purging with nitrogen gas, and the reaction is continued at 110℃ for 4 hours with a nitrogen gas flow rate of 20 ml / min.

[0055] The reaction was completed, yielding a brown, viscous product.

[0056] The raw materials and products were subjected to Fourier transform infrared (FTIR) tests separately. The FTIR spectrum of the bio-based phosphorus-containing polyester polyol prepared in this embodiment is shown below. Figure 1 As shown, the comparison reveals new infrared characteristic absorption peaks generated by the reaction, indicating successful synthesis.

[0057] Example 5

[0058] A method for preparing a bio-based phosphorus-containing polyester polyol, the specific preparation steps of which are as follows:

[0059] Accurately weigh 2 mol of tris(hydroxymethyl)phosphorus oxide and add it to a three-necked flask equipped with an oil bath. Set the oil bath to 50°C and preheat it at a constant temperature for 1 hour.

[0060] After preheating, accurately weigh 1 mol of phytic acid and use a peristaltic pump to gradually add the phytic acid dropwise into a three-necked flask containing polyol at a dropping rate of 6 rpm. It is expected that all the phytic acid will be added into the three-necked flask within 0.5 hours.

[0061] After the addition is complete, the reaction is kept at 60°C for 2 hours. At this time, the product in the three-necked flask should be a low molecular weight oligomer.

[0062] After the reaction is complete, the temperature of the oil bath is raised to 110°C and kept at this temperature for 2 hours.

[0063] After the reaction is complete, nitrogen gas is introduced into the entire system to remove volatile small molecules and water by purging with nitrogen gas, and the reaction is continued at 110℃ for 4 hours with a nitrogen gas flow rate of 30 ml / min.

[0064] The reaction was completed, yielding a brown, viscous product.

[0065] Fourier transform infrared spectroscopy was performed on the raw materials and the product, and the new infrared characteristic absorption peaks generated by the reaction were obtained by comparison, indicating that the synthesis was successful.

[0066] Example 6

[0067] A method for preparing a bio-based phosphorus-containing polyester polyol, the specific preparation steps are as follows: accurately weigh 2.25 mol of tris(hydroxymethyl)phosphorus oxide and add it to a three-necked flask equipped with an oil bath, adjust the oil bath to 50°C and preheat at a constant temperature for 1 hour;

[0068] After preheating, accurately weigh 1 mol of phytic acid and use a peristaltic pump to gradually add the phytic acid dropwise into a three-necked flask containing polyol at a dropping rate of 6 rpm. It is expected that all the phytic acid will be added into the three-necked flask within 0.5 hours.

[0069] After the addition is complete, the reaction is kept at 60°C for 2.5 hours. At this time, the product in the three-necked flask should be a low molecular weight oligomer.

[0070] After the reaction is complete, the temperature of the oil bath is raised to 120°C and kept at this temperature for 2 hours.

[0071] After the reaction is complete, nitrogen gas is introduced into the entire system to remove volatile small molecules and water by purging with nitrogen gas, and the reaction is continued at 110℃ for 4 hours with a nitrogen gas flow rate of 30 ml / min.

[0072] The reaction was completed, yielding a brown, viscous product.

[0073] Fourier transform infrared spectroscopy was performed on the raw materials and the product, and the new infrared characteristic absorption peaks generated by the reaction were obtained by comparison, indicating that the synthesis was successful.

[0074] Example 7

[0075] A method for preparing a bio-based phosphorus-containing polyester polyol, the specific preparation steps are as follows: accurately weigh 2.75 mol of tris(hydroxymethyl)phosphorus oxide and add it to a three-necked flask equipped with an oil bath, adjust the oil bath to 50°C and preheat at a constant temperature for 1 hour;

[0076] After preheating, accurately weigh 1 mol of phytic acid and use a peristaltic pump to gradually add the phytic acid dropwise into a three-necked flask containing polyol at a dropping rate of 6 rpm. It is expected that all the phytic acid will be added into the three-necked flask within 0.5 hours.

[0077] After the addition is complete, the reaction is kept at 60°C for 4 hours. At this time, the product in the three-necked flask should be a low molecular weight oligomer.

[0078] After the reaction is complete, the temperature of the oil bath is raised to 110°C and kept at this temperature for 3 hours.

[0079] After the reaction is complete, nitrogen gas is introduced into the entire system to remove volatile small molecules and water by purging with nitrogen gas, and the reaction is continued at 120℃ for 4 hours with a nitrogen gas flow rate of 20 ml / min.

[0080] The reaction was completed, yielding a brown, viscous product.

[0081] Fourier transform infrared spectroscopy was performed on the raw materials and the product, and the new infrared characteristic absorption peaks generated by the reaction were obtained by comparison, indicating that the synthesis was successful.

[0082] The moisture content, acid value, and hydroxyl value of the reactive bio-based phosphorus-containing polyester polyol prepared in this invention were determined.

[0083] The bio-based phosphorus-containing polyester polyol prepared in Example 7 of this application at a reaction temperature of 110°C has a hydroxyl value of 189 mgKOH / g, a water content of 3.26%, and an acid value of 2.89 mgKOH / g. The test data of other examples (Examples 4-6) are basically consistent with the above data.

[0084] The bio-based phosphorus-containing polyester polyol of the present invention gradually replaces the traditional polyether polyol. If the polyether polyol is 100 parts, the phosphorus-containing polyol replaces 10 parts, 20 parts, 30 parts, and 40 parts respectively, while other components remain the same. The specific formulation is shown in Tables 1-3 below.

[0085] Components Dosage (per serving) Dosage (per serving) Dosage (per serving) Dosage (per serving) Dosage (per serving) Polyether polyol 4110 100 90 80 70 60 Isocyanate PM200 120 112.7 104.9 97.1 89.4 Stabilizer M8805 2 2 2 2 2 water 2 2 2 2 2 Gel catalyst A33 0.5 0.5 0.5 0.5 0.5 Foaming catalyst T-12 1 1 1 1 1 Triethylamine 3 3 3 3 3 Example 7 Sample 0 10 20 30 40

[0086] Table 2

[0087]

[0088]

[0089] Table 3

[0090]

[0091] The effectiveness verification of the examples in Table 1 above is as follows: Figure 3-8 As shown, the limiting oxygen index (LOI) of rigid polyurethane foam (RPUF) without the phosphorus-containing polyester polyol of the present invention is 20.8% in a 10mm × 10mm × 100mm size. The limiting oxygen indices of the rigid polyurethane foam with 10, 20, 30, and 40 parts of the phosphorus-containing polyester polyol of Example 7 of the present invention in a 10mm × 10mm × 100mm size are 21.6%, 22.1%, 23.2%, and 23.8%, respectively. The rigid polyurethane foam (RPUF) without the phosphorus-containing polyester polyol of the present invention has a vertical burning (UL94) rating of V-2 in a 127mm × 13mm × 10mm size. The vertical burning (UL94) ratings of the rigid polyurethane foam with 10, 20, 30, and 40 parts of the phosphorus-containing polyester polyol of the present invention in a 127mm × 13mm × 10mm size are V-2, V-1, V-0, and V-0, respectively. Rigid polyurethane foam (RPUF) without the phosphorus-containing polyester polyol of this invention was subjected to cone-shaped calorimetry (radiative power of 35 kW / m²) in dimensions of 100 mm × 100 mm × 25 mm. 2 Its total heat release was measured to be 28.601 MJ / M. 2 The rigid polyurethane foams containing 10, 20, 30, and 40 parts of the phosphorus-containing polyester polyol of this invention exhibited a cone-shaped calorimetric analysis (radiant power of 35 kW / m²) with dimensions of 100 mm × 100 mm × 25 mm. 2 Its total heat release was measured to be 12.108 MJ / M. 2 10.465 MJ / M 2 9.529 MJ / M 2 5.77 MJ / M 2 .

[0092] The data obtained from the example measurements in Tables 2 and 3 are basically consistent with the data mentioned above.

[0093] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the scope of the patent application and the description of the invention shall still fall within the scope of the patent of the present invention.

Claims

1. A bio-based phosphorus-containing flame-retardant polyester polyol, characterized in that, It is made from the following components in molar percentages: Polyols 60-75% Polybasic acids 25-40% The polyol is trimethylolphosphine oxide, and the polyacid is phytic acid; The bio-based phosphorus-containing flame-retardant polyester polyol has a functionality of 30-40, a number-average molecular weight of 25,000-30,000, and a molecular weight distribution of 1-1.3; the hydroxyl value is 150-200 mgKOH / g.

2. The method for preparing a bio-based phosphorus-containing flame-retardant polyester polyol according to claim 1, characterized in that, The steps involved are as follows: (1) Weigh the polyol and add it to a container, which is a three-necked flask equipped with an oil bath. Adjust the temperature to the condensation reaction temperature of 40-80℃ and preheat for 0.5-1h. (2) Weigh out the polyacid and add it dropwise to the polyol prepared in (1) above using a peristaltic pump. The peristaltic pump dripping speed is 6-8 rpm. (3) React at a constant temperature of 40-80℃ for 1-3 hours; (4) Raise the temperature to 100-130℃ and maintain the temperature for 1-2 hours; (5) Nitrogen gas is introduced to remove water and volatile small molecules produced by the side reaction. The nitrogen gas flow rate is 15-30 ml / min and the gas flow time is 3-5 h.

3. The method for preparing a bio-based phosphorus-containing flame-retardant polyester polyol according to claim 2, characterized in that, In step (2), the polybasic acid should be added dropwise into the container within 0.5 hours; in step (3), the reaction temperature is 60°C.

4. The method for preparing a bio-based phosphorus-containing flame-retardant polyester polyol according to claim 3, characterized in that, The steps are as follows: Weigh out polyol and polyacid in a molar ratio of 3:1 to 3:

2. First, add the polyol to the container and preheat it at 60°C for 0.5 hours. Then, add the polyacid dropwise over 0.5 hours, maintaining the temperature at 60°C. Perform a constant-temperature condensation reaction for 2 hours. Raise the temperature to 110-120°C and introduce nitrogen gas at a rate of 20 mL / min to remove volatile water and small molecule products. The reaction time is 4-6 hours.

5. The application of the bio-based phosphorus-containing flame-retardant polyester polyol according to claim 1, characterized in that, It is used to prepare flame-retardant rigid polyurethane foam, and the addition amount is 10-40 parts by weight.

Images