A flame-retardant polyester polyol and a method for preparing the same, and a polyurethane flexible foam and a method for preparing the same

Abstract

The application discloses a kind of flame-retardant polyester polyols and preparation method thereof, a kind of polyurethane soft bubble and preparation method thereof, the preparation raw material of the flame-retardant polyester polyols includes: a) dicarboxylic acid, 80-120 mol parts;B) nitrogen-free diol, 50-150 mol parts;C) nitrogen-containing diol 2-90 mol parts.The low misting value flame-retardant polyester polyols have higher content of phosphorus and nitrogen elements, and have excellent synergistic flame-retardant performance.Meanwhile, after the polyester polyols are treated by thin film evaporator devolatilization, the polyester polyols meet the requirements of low misting value.The polyurethane soft bubble material synthesized using the low misting value flame-retardant polyester polyols shows excellent environmental protection and flame retardancy.

Description

Technical Field

[0001] This invention belongs to the field of polyester polyol technology, specifically relating to a method for preparing a low-fogging-value flame-retardant polyester polyol and its application in polyurethane flexible foam. Background Technology

[0002] Polyester polyols are compounds with hydroxyl-terminated structures formed by the reaction of aliphatic or aromatic dicarboxylic acids with polyols. Polyurethane flexible foams produced using polyester polyols as raw materials have advantages such as high mechanical strength and good oil and temperature resistance, and are therefore widely used in automotive interior materials, such as seats, headliners, dashboards, and steering wheels.

[0003] During the synthesis of polyester polyols, dicarboxylic acids react with the terminal hydroxyl groups of the diol to form cyclic ester byproducts. Intermolecular dehydration of the diol molecules forms epoxy byproducts. These small molecule byproducts lack hydroxyl groups and cannot react with isocyanates to form polymers; therefore, they remain as low-boiling-point impurities in the polyurethane flexible foam. Meanwhile, domestic and international automotive regulations have high requirements for the flame retardant performance of interior materials. Manufacturers typically add liquid flame retardants during the production of polyurethane flexible foam. These small molecule flame retardants gradually vaporize (or atomize) as the temperature rises. When a car is exposed to direct sunlight in summer, the slow air circulation inside the vehicle and temperatures reaching 70-90°C accelerate the volatilization of these small molecules. These volatilized small molecules from automotive interior materials float in the air, and passengers can inhale them, harming their health. They may also condense on car windows, affecting driving safety. Furthermore, the release of flame retardants from the polyurethane flexible foam reduces the flame retardancy of the interior materials, posing a serious safety risk. With the development of the automotive industry, automakers are paying increasing attention to the quality and performance of interior materials, one important indicator being the material's atomization performance. Therefore, actively developing flame-retardant polyester polyols with low atomization values ​​has broad prospects and development potential.

[0004] CN103649166B discloses a method for preparing phthalate polyester polyols with low cyclic ester content. The polyester polyol with low cyclic ester content is prepared by reacting phthalic anhydride with specific diols or mixtures of diols (e.g., ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, polyethylene glycol with a number-average molecular weight of 200 g / mol to 600 g / mol, and mixtures thereof). The synthesized phthalate polyester polyol has a cyclic ester content of 1 wt% or less. However, phthalate polyester polyols contain a large number of benzene ring structures, which generally have high strength and rigidity, resulting in poor flexibility and resilience in polyurethane flexible foam synthesized from them.

[0005] CN111040142A discloses a low-fogging, low-VOC polyester polyol and its preparation method. The low-fogging, low-VOC polyester polyol is produced by treating the polyester polyol using a scraped-film evaporator under high vacuum conditions to remove small molecules, thereby achieving low VOC and low fogging. However, the prepared low-VOC, low-fogging polyester polyol itself does not possess flame-retardant properties. Manufacturers need to add additional flame retardants to the formulation for synthesizing polyurethane flexible foam. The residual flame retardant within the polyurethane flexible foam may still lead to a higher fogging value in the product.

[0006] In summary, there is an urgent need in this field to develop a low-fogging-value flame-retardant raw material polyol to improve the safety, environmental friendliness, and flame retardancy of polyurethane flexible foam. Summary of the Invention

[0007] This invention addresses the aforementioned shortcomings of existing technologies by providing a flame-retardant polyester polyol and its preparation method, as well as a polyurethane flexible foam and its preparation method. The flame-retardant polyester polyol incorporates phosphorus and nitrogen, two flame-retardant elements, in appropriate proportions into its molecular chain, endowing it with synergistic flame-retardant properties. Simultaneously, the polyester polyol, after devolatilization treatment using a thin-film evaporator, meets the requirement of low fogging value. The polyurethane flexible foam material synthesized by this invention exhibits excellent low fogging and flame-retardant properties, showing broad application prospects.

[0008] This invention provides a flame-retardant polyester polyol, wherein the raw materials for preparing the polyester polyol include the following components:

[0009] a) Dicarboxylic acid, 80-120 molar parts, preferably 90-120 molar parts;

[0010] b) Contains no nitrogen-containing diols, 50-150 molars, preferably 60-120 molars;

[0011] c) Nitrogen-containing diols, 2-90 molar parts, preferably 30-80 molar parts.

[0012] In component a) of the present invention, the dicarboxylic acid is selected from aliphatic carboxylic acids having 2 to 20 carbon atoms. Specifically, the aliphatic dicarboxylic acid is selected from one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, and octadecanoic acid, more preferably succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, and octadecanoic acid, with adipic acid being the most preferred.

[0013] In component b) of the present invention, the nitrogen-free diol is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, and dipropylene glycol; preferably diethylene glycol.

[0014] In component c) of this invention, the nitrogen-containing diol has the following general structural formula:

[0015]

[0016] Wherein, R1 and R2 are independent of each other and are C1-C8 alkylene groups, or C1-C8 alkylene groups in which at least one hydrogen atom is replaced by a halogen, preferably C1-C4 alkylene groups.

[0017] Preferably, component c) of the present invention comprises one or more of the following structural formulas:

[0018]

[0019] In this invention, the preparation method of component c) includes the following steps:

[0020] c1) Under inert gas protection, di(hydroxymethyl) phosphate chloride and tert-butyl hydroxy(methyl)carbamate are added sequentially to the reactor, and the temperature is increased to react;

[0021] c2) Slowly add trifluoroacetic acid and solvent to the reactor and continue the reaction;

[0022] c3) Slowly add the reaction solution from step c2) to a vigorously stirred alkaline solution and separate.

[0023] In this invention, the temperature of the heating reaction in step c1) is 60-140℃ and the reaction time is 4.0-10.0h; preferably, the reaction temperature is 80-120℃ and the reaction time is 6.0-8.0h.

[0024] In this invention, the reaction temperature in step c2) is 10-60℃, and the reaction time is 2.0-8.0 h; preferably, the reaction temperature is 20-40℃, and the reaction time is 3.0-6.0 h. The solvent is selected from one or more of dichloromethane, dichloroethane, dichloropropane, and trichloroethane, preferably dichloromethane.

[0025] In this invention, the alkaline solution in step c3) is selected from aqueous solutions of sodium carbonate, sodium nitrate, potassium carbonate, and potassium carbonate, preferably an aqueous solution of sodium carbonate.

[0026] As a preferred embodiment, in step c3), the separation includes the following steps: liquid-liquid separation, extraction of the aqueous phase, merging of the organic phases, washing with water, drying, and concentration.

[0027] The synthesis reaction formula for component c) is shown below:

[0028]

[0029] On the other hand, the present invention also provides a method for preparing flame-retardant polyester polyol, comprising the following steps:

[0030] 1) Under inert gas protection, add components a), b), and c) sequentially to the reactor; react at 120-180℃ for 0.2-4.0h; preferably, react at 140-160℃ for 0.5-2.0h.

[0031] 2) Heat to 160-240℃ and hold for 0.2-4.0h, then test the product acid value to ≤15mgKOH / g; preferably, heat to 180-220℃ and hold for 1.0-3.0h.

[0032] 3) After adding the optional catalyst, the reactor is evacuated and kept at 180-260℃ for 1.0-8.0h, preferably at 200-240℃ for 3.0-6.0h. The product acid value is 0.01-5.00mgKOH / g and the hydroxyl value is 10-200mgKOH / g. The pressure is restored to normal, the temperature is lowered and the product is discharged to obtain macromolecular polyester polyol.

[0033] 4) The macromolecular polyester polyol is subjected to devolatilization treatment in a scraped film evaporator. The evaporator temperature is controlled at 150-250℃ and the pressure is 2-10Pa. Preferably, the evaporator temperature is 180-220℃ and the pressure is 4-8Pa. The material is discharged at 120℃ to obtain flame-retardant polyester polyol with low atomization value.

[0034] In this invention, the catalyst in step 3) is selected from one or more of titanium catalysts, amine catalysts, or tin catalysts; preferably, the titanium catalyst is selected from one or more of tetrabutyl titanate and tetraisopropyl titanate; the amine catalyst is selected from one or more of trimethylamine and triethylamine; the tin catalyst is selected from one or more of stannous octoate and dibutyltin dilaurate; more preferably, the catalyst in this invention is tetraisopropyl titanate; preferably, the amount of catalyst added is 0-500 ppm, more preferably 30-300 ppm, based on the total mass of polyester polyol raw materials.

[0035] In this invention, the flame-retardant polyester polyol has an acid value of 0.01-2.00 mgKOH / g, a hydroxyl value of 30-140 mgKOH / g, a cyclic ester content of 0-0.5 wt%, an epoxide content of 0-0.3 wt%, and a FOG value of 0-1500 ug / g; preferably, the flame-retardant polyester polyol has an acid value of 0.01-0.50 mgKOH / g, a hydroxyl value of 30-120 mgKOH / g, a cyclic ester content of 0-0.2 wt%, an epoxy content of 0-0.1 wt%, and a FOG value of 0-200 ug / g.

[0036] In this invention, the cyclic ester refers to a macrocyclic diester formed by the condensation of the terminal carboxyl group of a dicarboxylic acid with the terminal hydroxyl group of a diol molecule at the opposite end during the synthesis of polyester polyols, and is quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS).

[0037] In this invention, the epoxide refers to the epoxide formed by the intermolecular condensation of diols during the synthesis of polyester polyols, such as the intermolecular condensation of ethylene glycol to form 1,4-dioxane, which is quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS). The FOG value in step 4) refers to the amount of organic matter emitted within 30 minutes at 120°C.

[0038] Another object of the present invention is to provide the use of the polyester polyol in the preparation of polyurethane flexible foam.

[0039] A polyurethane flexible foam is obtained by reacting the following raw materials:

[0040] A: Flame-retardant polyester polyol: 52-58 parts by weight, preferably 52-54 parts by weight;

[0041] B: Polyether polyol: 12-18 parts by weight, preferably 14-16 parts by weight;

[0042] C: Polyisocyanate: 20-28 parts by weight, preferably 22-26 parts by weight;

[0043] D: Catalyst: 0.5-1.5 parts by weight, preferably 0.8-1.2 parts by weight;

[0044] E: Foaming agent: 1.0-3.0 parts by weight, preferably 1.5-2.5 parts by weight;

[0045] F: Foam stabilizer: 0.8-2.8 parts by weight, preferably 1.0-2.0 parts by weight;

[0046] In some specific embodiments, the polyether polyol in component B can be selected from polyether polyols with a functionality of 3 and a number-average molecular weight of 1500-5000. Preferably, the polyether polyol is selected from one or more of Wanhua Chemical F3135, Lanxing Dongda 10LD76EK, and Yinuowei F8001A, and more preferably... F3135.

[0047] In some specific embodiments, the polyisocyanate in component C includes one or more of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), terephthalic diisocyanate (PPDI), hexamethylene diisocyanate (HDI), 1,10-decane diisocyanate, 1,11-undecane diisocyanate, 1,12-dodecane diisocyanate, isophorone diisocyanate (IPDI), 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate (CHDI), hexane-hexylmethane diisocyanate (HMDI), cyclohexanedimethyl diisocyanate (HXDI), and polyphenyl polymethylene polyisocyanate (PAPI); preferably.

[0048] In some specific embodiments, the catalyst in component D includes one or more of pentamethyldiethylenetriamine, tetramethylhexanediamine, bis-dimethylaminoethyl ether, dimethylcyclohexylamine, triethylenediamine, triethylamine, tributylamine, N,N-dimethylcyclohexylamine, triethylenediamine, triethylenediamine, tetramethylethylenediamine, stannous octoate, and dibutyltin dilaurate. Preferably, one or more of A33, A1, A30, and B9 are used; more preferably, A33 is used.

[0049] In some specific implementations, the foaming agent in component E is water.

[0050] In some specific embodiments, the foam stabilizer in component F is not particularly limited, as long as it can play a role in stabilizing the foam. It is preferably selected from one or more of organopolysiloxanes, ethoxylated fatty alcohols, alkylphenols and castor oil esters; more preferably Momentive Y-16455.

[0051] Furthermore, the present invention also provides a method for preparing the polyurethane flexible foam, comprising the following steps:

[0052] 1) Mix flame-retardant polyester polyol, polyether polyol, catalyst, foaming agent, water, and foam stabilizer evenly to obtain a mixture;

[0053] 2) Add the polyisocyanate to the mixture in step 1) while stirring, and then pour it into a mold at a temperature of 40-60°C for natural foaming;

[0054] 3) After cooling at room temperature, place in an oven at 40-60℃ for 6-8 hours to mature.

[0055] Compared with the prior art, the above-described technical solution of the present invention has at least the following beneficial effects:

[0056] (1) The present invention synthesizes a polyester polyol using dicarboxylic acid and diol containing phosphorus and nitrogen as raw materials. The molecular structure of the polyester polyol simultaneously introduces phosphorus and nitrogen, which endows the polyester polyol with synergistic flame retardant properties. This effectively overcomes the problem of easy precipitation and migration of current additive flame retardants, and provides support for improving the flame retardant ability of polyester polyol and polyurethane flexible foam.

[0057] (2) This invention uses a thin-film evaporator to perform devolatilization treatment on the synthesized macromolecular polyester polyol, removing residual cyclic esters, epoxides and other impurities, to obtain a low-atomization-value flame-retardant polyester polyol. The polyurethane flexible foam synthesized using the low-atomization-value flame-retardant polyester polyol has an atomization value of less than 200 μg / g, an oxygen index of up to 27.8%, and a vertical flammability rating of V0, meeting the usage requirements of the automotive industry. Attached Figure Description

[0058] Figure 1 For C1, 1H NMR spectrum analysis;

[0059] Figure 2 The 1H NMR spectrum analysis for C2. Detailed Implementation

[0060] The present invention will be further described below with reference to specific embodiments. The embodiments described herein are merely illustrative and do not limit the scope of the invention.

[0061] The main raw materials used in the preparation examples and embodiments include: TDI80 purchased from Wanhua Chemical and other companies; di(hydroxymethyl)phosphophosphate (CAS: 1287267-92-8), tert-butyl hydroxy(methyl)carbamate (CAS: 19689-97-5), and trifluoroacetic acid purchased from Inokai and other companies; adipic acid purchased from Huafeng Chemical and other companies; tetraisopropyl titanate and triphenyl phosphate purchased from Aladdin and other companies; A33 purchased from Zibo Senhe Chemical; and Y-16455 purchased from Momentive. Unless otherwise specified, all raw materials used were obtained through commercial channels.

[0062] The test methods involved in the products of the embodiments and comparative examples include:

[0063] Acid value: The acid value test for polyester polyol products refers to HG / T2709-1995;

[0064] Hydroxyl value: The hydroxyl value test for polyester polyol products refers to HG / T2708-1995;

[0065] Moisture content: Moisture testing for polyester polyol products should refer to GB / T6283-2008;

[0066] Color code: Color code testing for polyester polyol products refers to GB / T3143-1982;

[0067] Cyclic ester content: The cyclic ester content of the polyester polyol products was quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS).

[0068] Fogging value: The FOG value test for polyester polyol and polyurethane flexible foam is referenced to VDA278;

[0069] Density: The density test method for polyurethane flexible foam refers to GB / T 10807-2006B;

[0070] Tensile strength and elongation at break: The tensile properties of polyurethane flexible foam are tested according to GB / T 6344-2008.

[0071] Tear strength: The tear strength test of polyurethane flexible foam refers to GB / T 10808-2006;

[0072] Flame retardant performance: The flame retardant performance test of polyurethane flexible foam is based on GA303-2001.

[0073] Preparation Example 1

[0074] This preparation example provides a method for synthesizing nitrogen-containing diol C1, as follows:

[0075] 100 g of di(hydroxymethyl)phosphate and 90 g of tert-butyl hydroxymethylcarbamate were added sequentially to a three-necked flask, and nitrogen protection was applied. The reactor was heated to 120 °C under normal pressure and maintained at this temperature for 6.0 h. Next, 600 mL of trifluoroacetic acid and 2.4 L of dichloromethane were added to the reactor, and the reaction was maintained at 40 °C for 3.0 h. Finally, the reaction solution was slowly added dropwise to a vigorously stirred sodium carbonate solution. After the addition was complete, the mixture was separated, and the aqueous phase was extracted twice more. The organic phases were combined, and the product was washed with water, dried, and concentrated to obtain 76 g of product C1. The 1H NMR spectrum analysis of C1 is shown in the appendix. Figure 1 .

[0076]

[0077] Preparation Example 2

[0078] This preparation example provides a method for synthesizing nitrogen-containing diol C1, as follows:

[0079] 100 g of di(hydroxyethyl) phosphate chloride and 90 g of tert-butyl hydroxy(methyl)carbamate were added sequentially to a three-necked flask, and nitrogen protection was applied. The reaction vessel was heated to 80 °C under normal pressure and maintained at this temperature for 8.0 h. Next, 700 mL of trifluoroacetic acid and 2.8 L of dichloromethane were added to the reaction vessel, and the reaction was maintained at 20 °C for 6.0 h. Finally, the reaction solution was slowly added dropwise to a vigorously stirred sodium carbonate solution. After the addition was complete, the mixture was separated, and the aqueous phase was extracted twice more. The organic phases were combined, and the product was washed with water, dried, and concentrated to obtain 65 g of product C2. The 1H NMR spectrum analysis of C2 is shown below. Figure 2 .

[0080]

[0081] Comparative Example 1

[0082] 1) Under a nitrogen atmosphere, add 15.9 kg of diethylene glycol and 17.5 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 150°C under normal pressure and maintain this temperature for 0.5 h.

[0083] 2) Next, the reactor is heated to 160°C under normal pressure and maintained at this temperature for 1 hour. The acid value of the product is then tested and found to be ≤15mgKOH / g.

[0084] 3) Next, after adding 10g of tetraisopropyl titanate, the reactor was evacuated and the reaction temperature was 220℃, which was maintained for 4.0h. The product's acid value was 0.50mgKOH / g, and the hydroxyl value was 44.9mgKOH / g. The pressure was restored to normal, and the temperature was lowered to 120℃ before discharge, yielding a macromolecular polyester polyol with a cyclic ester content of 0.39wt%, an epoxide content of 0.25wt%, and a FOG value of 1480μg / g.

[0085] Comparative Example 2

[0086] 1) Under a nitrogen atmosphere, add 5.3 kg of diethylene glycol, 0.9 kg of Cl, and 13.2 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 120°C under normal pressure and maintain this temperature for 1 hour.

[0087] 2) Next, the reactor is heated to 170°C under normal pressure and maintained at this temperature for 1 hour. The acid value of the product is then tested and found to be ≤15mgKOH / g.

[0088] 3) Next, after adding 3.8g of tetraisopropyl titanate, the reactor was evacuated, and the reaction temperature was 185℃, maintained at this temperature for 3.0h. The product's acid value was 0.80mgKOH / g, and the hydroxyl value was 30mgKOH / g. The pressure was restored to normal, and the temperature was lowered to 120℃ before discharge, yielding a macromolecular polyester polyol with a cyclic ester content of 0.45wt%, an epoxide content of 0.28wt%, and a FOG value of 1500μg / g.

[0089] Comparative Example 3

[0090] 1) Under a nitrogen atmosphere, add 7.4 kg of diethylene glycol, 16.2 kg of Cl, and 14.6 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 130°C under normal pressure and maintain this temperature for 0.5 h.

[0091] 2) Next, the reactor is heated to 190°C under normal pressure and maintained at this temperature for 2 hours. The acid value of the product is then tested and found to be ≤15mgKOH / g.

[0092] 3) Next, after adding 1.9g of tetraisopropyl titanate, the reactor was evacuated, and the reaction temperature was 215℃, maintained at this temperature for 4.0h. The product's acid value was 0.2mgKOH / g, and the hydroxyl value was 52mgKOH / g. The pressure was restored to normal, and the temperature was lowered to 120℃ before discharge, yielding a macromolecular polyester polyol with a cyclic ester content of 0.28wt%, an epoxide content of 0.21wt%, and a FOG value of 1420μg / g.

[0093] Comparative Example 4

[0094] 1) Under a nitrogen atmosphere, add 3.2 kg of diethylene glycol, 1 kg of C2, and 11.7 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 135°C under normal pressure and maintain this temperature for 1.5 hours.

[0095] 2) Next, the reactor is heated to 220°C under normal pressure and maintained at this temperature for 3 hours. The acid value of the product is then tested and found to be ≤15mgKOH / g.

[0096] 3) Next, after adding 2.1g of tetraisopropyl titanate, the reactor was evacuated, and the reaction temperature was 240℃, maintained at this temperature for 5.0h. The product's acid value was 0.9mgKOH / g, and the hydroxyl value was 40mgKOH / g. The pressure was restored to normal, and the temperature was lowered to 120℃ before discharge, yielding a macromolecular polyester polyol with a cyclic ester content of 0.38wt%, an epoxide content of 0.24wt%, and a FOG value of 1470μg / g.

[0097] Comparative Example 5

[0098] 1) Under a nitrogen atmosphere, add 3.2 kg of diethylene glycol, 15.8 kg of C2, and 11.7 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 135°C under normal pressure and maintain this temperature for 2 hours.

[0099] 2) Next, the reactor is heated to 240°C under normal pressure and maintained at this temperature for 3 hours. The acid value of the product is then tested and found to be ≤15mgKOH / g.

[0100] 3) Next, the reactor was evacuated, and the reaction temperature was 240℃, which was maintained for 1.0 h. The product acid value was measured to be 1.0 mg KOH / g, and the hydroxyl value was 80 mg KOH / g. The pressure was restored to normal, and the temperature was lowered to 120℃ before discharge, yielding a macromolecular polyester polyol with a cyclic ester content of 0.33 wt%, an epoxide content of 0.22 wt%, and a FOG value of 1425 μg / g.

[0101] Example 1

[0102] 1) Under a nitrogen atmosphere, add 7.4 kg of diethylene glycol, 1.8 kg of Cl, and 14.6 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 175°C under normal pressure and maintain this temperature for 2.5 hours.

[0103] 2) Next, the reactor was heated to 178°C under normal pressure and maintained at this temperature for 1.5 hours. The acid value of the product was measured to be ≤15mgKOH / g.

[0104] 3) Next, after adding 3.6g of tetraisopropyl titanate, the reactor was evacuated, and the reaction temperature was 180℃, maintained at this temperature for 3.0h. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered, and the product was discharged to obtain macromolecular polyester polyol;

[0105] 4) The macromolecular polyester polyol was subjected to devolatilization treatment in a scraped-film evaporator, with the evaporator temperature controlled at 150℃ and the pressure at 2Pa. The product's acid value was measured to be 0.30 mgKOH / g, and its hydroxyl value was 130 mgKOH / g. After restoring to normal pressure and cooling to 120℃, the product was discharged, yielding a low-misting-value flame-retardant polyester polyol with a cyclic ester content of 0.16 wt%, an epoxide content of 0.10 wt%, and a FOG value of 198 μg / g.

[0106] Example 2

[0107] 1) Under a nitrogen atmosphere, add 7.9 kg of diethylene glycol, 0.4 kg of Cl, and 15.3 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 165°C under normal pressure and maintain this temperature for 1.5 hours.

[0108] 2) Next, the reactor is heated to 175°C under normal pressure and maintained at this temperature for 1 hour. The acid value of the product is then tested and found to be ≤15mgKOH / g.

[0109] 3) Next, after adding 12.1g of tetraisopropyl titanate, the reactor was evacuated and the reaction temperature was 250℃, which was maintained for 6 hours. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered, and the product was discharged to obtain macromolecular polyester polyol;

[0110] 4) The macromolecular polyester polyol was subjected to devolatilization treatment in a scraped-film evaporator, with the evaporator temperature controlled at 200℃ and the pressure at 6Pa. The product's acid value was measured to be 1.5 mgKOH / g, and its hydroxyl value was 140 mgKOH / g. After restoring to normal pressure and cooling to 120℃, the product was discharged, yielding a low-misting-value flame-retardant polyester polyol with a cyclic ester content of 0.13 wt%, an epoxide content of 0.07 wt%, and a FOG value of 92 μg / g.

[0111] Example 3

[0112] 1) Under a nitrogen atmosphere, add 10.6 kg of diethylene glycol, 8.5 kg of Cl, and 16 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 130°C under normal pressure and maintain this temperature for 3 hours.

[0113] 2) Next, the reactor was heated to 160°C under normal pressure and maintained at this temperature for 2.1 hours. The acid value of the product was measured to be ≤15mgKOH / g.

[0114] 3) Next, after adding 8.1g of tetraisopropyl titanate, the reactor was evacuated, and the reaction temperature was 255℃, which was maintained for 4.5h. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered, and the product was discharged to obtain macromolecular polyester polyol;

[0115] 4) The macromolecular polyester polyol was subjected to devolatilization treatment in a scraped-film evaporator, with the evaporator temperature controlled at 220℃ and the pressure at 4Pa. The product's acid value was measured to be 0.6 mgKOH / g, and its hydroxyl value was 120 mgKOH / g. After restoring to normal pressure and cooling to 120℃, the product was discharged, yielding a low-misting-value flame-retardant polyester polyol with a cyclic ester content of 0.10 wt%, an epoxide content of 0.05 wt%, and a FOG value of 56 μg / g.

[0116] Example 4

[0117] 1) Under a nitrogen atmosphere, add 10.6 kg of diethylene glycol, 14.4 kg of Cl, and 16 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 130°C under normal pressure and maintain this temperature for 3 hours.

[0118] 2) Next, the reactor was heated to 160°C under normal pressure and maintained at this temperature for 2.1 hours. The acid value of the product was measured to be ≤15mgKOH / g.

[0119] 3) Next, after adding 9.4g of tetraisopropyl titanate, the reactor was evacuated, and the reaction temperature was 255℃, which was maintained for 4.5h. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered, and the product was discharged to obtain macromolecular polyester polyol;

[0120] 4) The macromolecular polyester polyol was subjected to devolatilization treatment in a scraped-film evaporator, with the evaporator temperature controlled at 250℃ and the pressure at 2Pa. The product's acid value was measured to be 0.4 mgKOH / g, and its hydroxyl value to be 60 mgKOH / g. After restoring to normal pressure and cooling to 120℃, the product was discharged, yielding a low-misting-value flame-retardant polyester polyol with a cyclic ester content of 0.03 wt%, an epoxide content of 0.02 wt%, and a FOG value of 35 μg / g.

[0121] Example 5

[0122] 1) Under a nitrogen atmosphere, add 12.7 kg of diethylene glycol, 1.8 kg of C2, and 11.7 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 140°C under normal pressure and maintain this temperature for 2 hours.

[0123] 2) Next, the reactor was heated to 170°C under normal pressure and maintained at this temperature for 2.5 hours. The acid value of the product was measured to be ≤15mgKOH / g.

[0124] 3) Next, after adding 3.9g of tetraisopropyl titanate, the reactor was evacuated and the reaction temperature was 240℃, which was maintained for 4 hours. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered, and the product was discharged to obtain macromolecular polyester polyol;

[0125] 4) The macromolecular polyester polyol was subjected to devolatilization treatment in a scraped-film evaporator, with the evaporator temperature controlled at 160℃ and the pressure at 9Pa. The product's acid value was measured to be 0.2 mgKOH / g, and its hydroxyl value was 48 mgKOH / g. After restoring to normal pressure and cooling to 120℃, the product was discharged, yielding a low-misting-value flame-retardant polyester polyol with a cyclic ester content of 0.15 wt%, an epoxide content of 0.08 wt%, and a FOG value of 164 μg / g.

[0126] Example 6

[0127] 1) Under a nitrogen atmosphere, add 6.4 kg of diethylene glycol, 2.0 kg of C2, and 12.4 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 155°C under normal pressure and maintain this temperature for 4 hours.

[0128] 2) Next, the reactor is heated to 180°C under normal pressure and maintained at this temperature for 4 hours. The acid value of the product is then tested and found to be ≤15mgKOH / g.

[0129] 3) Next, after adding 2.1g of tetraisopropyl titanate, the reactor was evacuated and the reaction temperature was 260℃, which was maintained for 5 hours. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered, and the product was discharged to obtain macromolecular polyester polyol;

[0130] 4) The macromolecular polyester polyol was subjected to devolatilization treatment in a scraped-film evaporator, with the evaporator temperature controlled at 230℃ and the pressure at 3Pa. The product's acid value was measured to be 0.7 mgKOH / g, and its hydroxyl value to be 55 mgKOH / g. After restoring to normal pressure and cooling to 120℃, the product was discharged, yielding a low-misting-value flame-retardant polyester polyol with a cyclic ester content of 0.08 wt%, an epoxide content of 0.04 wt%, and a FOG value of 45 μg / g.

[0131] Example 7

[0132] 1) Under a nitrogen atmosphere, add 6.9 kg of diethylene glycol, 17.8 kg of C2, and 13.2 kg of adipic acid sequentially to the reactor and stir until homogeneous. Heat the reactor to 180°C under normal pressure and maintain this temperature for 0.2 h.

[0133] 2) Next, the reactor is heated to 200℃ under normal pressure and maintained at this temperature for 0.2h. The acid value of the product is measured to be ≤15mgKOH / g.

[0134] 3) Next, after adding 9.0g of tetraisopropyl titanate, the reactor was evacuated and the reaction temperature was 240℃, which was maintained for 8 hours. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered, and the product was discharged to obtain macromolecular polyester polyol;

[0135] 4) The macromolecular polyester polyol was subjected to devolatilization treatment in a scraped-film evaporator, with the evaporator temperature controlled at 240℃ and the pressure at 4Pa. The product's acid value was measured to be 0.9 mgKOH / g, and its hydroxyl value was 78 mgKOH / g. After restoring to normal pressure and cooling to 120℃, the product was discharged, yielding a low-misting-value flame-retardant polyester polyol with a cyclic ester content of 0.07 wt%, an epoxide content of 0.03 wt%, and a FOG value of 38 μg / g.

[0136] Preparation of polyurethane flexible foam 1-12

[0137] 1) According to the synthesis formula in Table 1, take polyester polyol, polyether polyol, catalyst, foaming agent, water and foam stabilizer, mix and stir evenly to obtain a mixture;

[0138] 2) Add the polyisocyanate to the mixture in step 1) while stirring, and then pour it into a mold at a temperature of 40-60°C for natural foaming;

[0139] 3) After cooling at room temperature, place the sample in an oven at 40-60℃ for 6-8 hours to mature. Then remove the mold used to foam the polyurethane composite material to obtain a polyurethane flexible foam sample.

[0140] Table 1. Formulations (parts by weight) of polyurethane flexible foam 1-12

[0141]

[0142]

[0143] Performance testing

[0144] The atomization value, density, tensile strength, elongation at break, tear strength, oxygen index, and vertical flammability rating of the polyurethane flexible foam were determined according to the above method, and the results are shown in Table 2. The data in the table show that the polyurethane flexible foam prepared from the low-atomization-value flame-retardant polyester polyol provided by this invention has a basically consistent density and exhibits low atomization performance, with the lowest atomization value reaching 117 μg / g. Simultaneously, the prepared polyurethane flexible foam has excellent flame-retardant properties, with an oxygen index reaching a maximum of 19.7% and a flame-retardant rating reaching V0, meeting the usage requirements of the automotive industry.

[0145] Analysis of polyurethane flexible foam 1 and polyurethane flexible foam 6-12 shows that using diols containing both phosphorus and nitrogen as raw materials in the synthesis formulation of polyester polyols can significantly improve the flame retardancy of polyurethane flexible foam. Furthermore, the higher the proportion of nitrogen-containing diol monomers, the more significant the improvement in flame retardancy. This is because phosphorus and nitrogen have a synergistic flame-retardant effect in the system. During combustion, phosphorus-containing substances decompose to produce phosphorus-containing derivatives, which cover the surface of the unburned substrate to form a char layer, isolating oxygen. Simultaneously, the nitrogen element in the chain decomposes upon heating, easily releasing non-flammable gases such as ammonia, nitrogen, and water vapor. These gases can carry away most of the heat, lowering the surface temperature of the material.

[0146] Analysis of polyurethane flexible foams 2-5 and 6-12 shows that after synthesizing the macromolecular polyester polyol, using a thin-film evaporator for devolatilization treatment can significantly reduce the atomization value of the macromolecular flame-retardant polyester polyol. Furthermore, higher evaporation temperatures and vacuum levels in the thin-film evaporator are more conducive to the evaporation of residual small molecules such as cyclic esters and epoxides in the macromolecular flame-retardant polyester polyol, resulting in superior low-atomization performance for both the polyester polyol and the polyurethane flexible foam. Polyurethane flexible foam 9, synthesized using a low-atomization-value polyester polyol, achieves a minimum atomization value of 117 μg / g.

[0147] Table 2 Performance parameters of polyurethane flexible foam 1-12

[0148]

[0149] The present invention has been illustrated with the above embodiments to explain the detailed method of the present invention. However, the present invention is not limited to the detailed method described above, that is, it does not mean that the present invention must rely on the detailed method described above to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A flame-retardant polyester polyol, prepared from raw materials comprising the following components: a) Dicarboxylic acid, 80-120 molar parts; b) Contains no nitrogen-containing diols, 50-150 molar parts; c) Nitrogen-containing diols, 2-90 molar parts; The nitrogen-containing diol has the following general structural formula: , in, R1 and R2 are independent C1-C8 alkylene groups, and C1-C8 alkylene groups in which at least one hydrogen atom is replaced by a halogen.

2. The flame-retardant polyester polyol as described in claim 1 is prepared from raw materials comprising the following components: a) Dicarboxylic acids, 90-120 molar parts; b) Contains no nitrogen-containing diols, 60-120 molars; c) Nitrogen-containing diols, 30-80 molars.

3. The flame-retardant polyester polyol as described in claim 1, characterized in that, In component a), the dicarboxylic acid is selected from aliphatic carboxylic acids having 2 to 20 carbon atoms.

4. The flame-retardant polyester polyol as described in claim 1, characterized in that, In component a), the dicarboxylic acid is selected from one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, and octadecanoic acid.

5. The flame-retardant polyester polyol as described in claim 1, characterized in that, In component b), the nitrogen-free diol is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, and dipropylene glycol.

6. The flame-retardant polyester polyol as described in claim 1, characterized in that, In the general formula of the nitrogen-containing diol, R1 and R2 are independent C1-C4 alkylene groups.

7. The flame-retardant polyester polyol as described in claim 1, characterized in that, Component c) includes one or more of the following structural formulas: 、 。 8. The flame-retardant polyester polyol as described in claim 1, characterized in that, The preparation method of component c) includes the following steps: c1) Under inert gas protection, di(hydroxymethyl) phosphate and tert-butyl hydroxy(methyl)carbamate were added sequentially to the reactor, and the temperature was increased to react. c2) Slowly add trifluoroacetic acid and solvent to the reactor and continue the reaction; c3) Slowly add the reaction solution from step c2) to a vigorously stirred alkaline solution and separate them.

9. A method for preparing the flame-retardant polyester polyol according to any one of claims 1-8, comprising the following steps: 1) Under inert gas protection, add components a), b), and c sequentially to the reactor and react at 120-180℃ for 0.2-4.0 h; 2) Heat to 160-240℃ and maintain for 0.2-4.0h. Detect the acid value of the product as ≤15mgKOH / g. 3) After adding the optional catalyst, the reactor is evacuated and kept at 180-260℃ for 1.0-8.0h. The acid value of the product is 0.01-5.00mgKOH / g and the hydroxyl value is 10-200mgKOH / g. The pressure is restored to normal, the temperature is reduced and the product is discharged to obtain macromolecular polyester polyol. 4) The macromolecular polyester polyol is subjected to devolatilization treatment in a scraped film evaporator. The evaporator temperature is controlled at 150-250℃ and the pressure is 2-10 Pa. The material is discharged at 120℃ to obtain flame-retardant polyester polyol.

10. A method for preparing the flame-retardant polyester polyol according to any one of claims 1-8, comprising the following steps: 1) Under inert gas protection, add components a), b), and c sequentially to the reactor and react at 140-160℃ for 0.5-2.0 h; 2) Heat to 180-220℃ and maintain for 1.0-3.0 hours. The acid value of the product should be ≤15mgKOH / g. 3) After adding the optional catalyst, the reactor is evacuated and kept at 200-240℃ for 3.0-6.0h. The acid value of the product is 0.01-5.00mgKOH / g and the hydroxyl value is 10-200mgKOH / g. The pressure is restored to normal, the temperature is reduced and the product is discharged to obtain macromolecular polyester polyol. 4) The macromolecular polyester polyol is subjected to devolatilization treatment in a scraped film evaporator. The evaporator temperature is controlled at 180-220℃ and the pressure is 4-8 Pa. The material is discharged at 120℃ to obtain flame-retardant polyester polyol.

11. The method as described in claim 9, characterized in that, The flame-retardant polyester polyol has an acid value of 0.01-2.00 mgKOH / g, a hydroxyl value of 30-140 mgKOH / g, a cyclic ester content of 0-0.5 wt%, an epoxide content of 0-0.3 wt%, and a FOG value of 0-1500 ug / g.

12. The method as described in claim 9, characterized in that, The flame-retardant polyester polyol has an acid value of 0.01-0.50 mgKOH / g, a hydroxyl value of 30-120 mgKOH / g, a cyclic ester content of 0-0.2 wt%, an epoxy content of 0-0.1 wt%, and a FOG value of 0-200 ug / g.

13. A polyurethane flexible foam, obtained by reacting the following raw materials: A: 52-58 parts by weight of the flame-retardant polyester polyol according to any one of claims 1-8; B: Polyether polyol: 12-18 parts by weight; C: Polyisocyanate: 20-28 parts by weight; D: Catalyst: 0.5-1.5 parts by weight; E: Foaming agent: 1.0-3.0 parts by weight; F: Foam stabilizer: 0.8-2.8 parts by weight.

14. A polyurethane flexible foam, obtained by reacting the following raw materials: A: 52-54 parts by weight of the flame-retardant polyester polyol according to any one of claims 1-8; B: Polyether polyol: 14-16 parts by weight; C: Polyisocyanate: 22-26 parts by weight; D: Catalyst: 0.8-1.2 parts by weight; E: Foaming agent: 1.5-2.5 parts by weight; F: Foam stabilizer: 1.0-2.0 parts by weight.

15. A method for preparing the polyurethane flexible foam according to claim 13 or 14, comprising the following steps: 1) Mix flame-retardant polyester polyol, polyether polyol, catalyst, foaming agent, water, and foam stabilizer evenly to obtain a mixture; 2) Add the polyisocyanate to the mixture in step 1) while stirring, and then pour it into a mold at a temperature of 40-60°C for natural foaming; 3) After cooling at room temperature, place in an oven at 40-60℃ for 6-8 hours to mature.

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