Flame-retardant polyester polyol, preparation method of flame-retardant polyester polyol, polyurethane flexible foam and preparation method of polyurethane flexible foam

Abstract

The invention discloses flame-retardant polyester polyol and a preparation method thereof, and polyurethane flexible foam and a preparation method thereof, and the flame-retardant polyester polyol is prepared from the following raw materials: a) 80-120 mol parts of dicarboxylic acid; b) 50 to 150 mol parts of nitrogen-free dihydric alcohol; and C) 2-90 mol parts of nitrogen-containing dihydric alcohol. The flame-retardant polyester polyol with the low atomization value is relatively high in content of phosphorus and nitrogen elements and has excellent synergistic flame-retardant performance. Meanwhile, the polyester polyol subjected to devolatilization treatment by the film evaporator meets the requirement of low atomization value. A polyurethane flexible foam material synthesized by using the flame-retardant polyester polyol with the low atomization value shows excellent environmental protection property and flame retardance.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester polyols, and specifically relates to a preparation method of low-fogging value flame-retardant polyester polyol and application thereof in polyurethane soft foam. Background Art

[0002] Polyester polyols are hydroxyl-terminated compounds formed by the reaction of aliphatic or aromatic dicarboxylic acids and polyols. Polyurethane soft foam produced with polyester polyols has the advantages of high mechanical strength, good oil and temperature resistance, etc., so it is widely used in automotive interior materials, such as seats, ceilings, dashboards and steering wheels.

[0003] In the synthesis process of polyester polyols, dicarboxylic acids react with the terminal hydroxyl groups of diols to form cyclic ester byproducts, and self-dehydration between diol molecules will form epoxy byproducts. These small molecular byproducts have no hydroxyl groups and cannot react with isocyanates to form polymers. Therefore, they remain in the polyurethane soft foam as a low-boiling impurity. At the same time, domestic and foreign automotive regulations have high requirements for the flame retardancy of interior materials. Manufacturers generally add liquid flame retardants in the production process of polyurethane soft foam. These small molecular flame retardants will gradually vaporize (or atomize) with the increase of temperature. When the car is exposed to the sun in summer, the air circulation in the car is slow and the temperature reaches 70-90℃, which accelerates the volatilization of these small molecular substances. The small molecular substances volatilized in the car interior float in the air, and the passengers bring them into the body with breathing, which is harmful to their health. They may also condense on the car windows, affecting driving safety. At the same time, the precipitation of flame retardants in polyurethane soft foam will also reduce the flame retardancy of interior materials, causing serious safety risks. With the development of the automobile industry, automobile manufacturers are paying more and more attention to the quality and performance of interior materials, one of the important indicators of which is the atomization performance of the material. Therefore, actively developing low atomization value flame retardant polyester polyols has broad prospects and development space.

[0004] CN103649166B discloses a method for preparing a phthalate polyester polyol with a low cyclic ester content, wherein the polyester polyol with a low cyclic ester content is prepared by reacting phthalic anhydride with a specific diol or diol mixture (e.g., ethylene glycol, propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propylene glycol, neopentyl glycol, 1,6-hexanediol, polyethylene glycol with a number average molecular weight of 200 g / mol to 600 g / mol, and a mixture thereof), and the synthesized phthalate polyester polyol has a cyclic ester content of 1 wt% or less. However, the phthalate polyester polyol contains a large amount of benzene ring structures and generally has high strength and rigidity, and the polyurethane soft foam synthesized as a raw material has poor softness and resilience.

[0005] CN111040142A discloses a low-fogging, low-VOC polyester polyol and a preparation method thereof, wherein the low-fogging, low-VOC polyester polyol is processed by a scraper-type thin film evaporator to remove small molecules in the polyester polyol under high vacuum conditions, thereby achieving the purpose of low VOC and low fogging. However, the prepared low-VOC, low-fogging polyester polyol itself does not have flame retardant ability, and manufacturers need to add additional flame retardants in the formula of synthetic polyurethane soft foams. The flame retardants remaining in the polyurethane soft foams may still cause the product's fogging value to be high.

[0006] In summary, the art urgently needs to develop a low-fogging value flame-retardant raw material polyol to improve the safety, environmental protection and flame retardancy of polyurethane soft foam. Summary of the invention

[0007] The present invention aims at the above-mentioned deficiencies in the prior art and provides a flame-retardant polyester polyol and a preparation method thereof, a polyurethane soft foam and a preparation method thereof. Two flame-retardant elements, phosphorus and nitrogen, are introduced into the molecular chain of the flame-retardant polyester polyol in a suitable proportion, giving the polyester polyol a synergistic flame-retardant property. At the same time, the polyester polyol after devolatilization treatment by a thin film evaporator meets the requirement of low atomization value. The polyurethane soft foam material synthesized by the present invention shows excellent low atomization and flame retardancy, and has broad application prospects.

[0008] The present 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 mol parts, preferably 90-120 mol parts;

[0010] b) 50-150 mol parts, preferably 60-120 mol parts, of a nitrogen-free diol;

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

[0012] In the component a) of the present invention, the dicarboxylic acid is selected from aliphatic carboxylic acids having carbon atoms of 2 to 20. Specifically, the aliphatic dicarboxylic acid is selected from one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedioic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, pentadecanedicarboxylic acid, hexadecanedicarboxylic acid, heptadecanedioic acid, and octadecanedicarboxylic acid, and is further preferably one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedioic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, pentadecanedicarboxylic acid, hexadecanedicarboxylic acid, heptadecanedioic acid, and octadecanedicarboxylic acid, and is preferably adipic acid.

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

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

[0015]

[0016] Among them, R 1 , R 2 The alkylene groups are independently C1-C8 alkylene groups, C1-C8 alkylene groups in which at least one hydrogen atom is substituted by halogen, and preferably C1-C4 alkylene groups.

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

[0018]

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

[0020] c1) under the protection of inert gas, di(hydroxymethyl) chlorophosphate and tert-butyl hydroxy(methyl)carbamate are added into the reactor in sequence, and the temperature is raised for reaction;

[0021] c2) slowly adding trifluoroacetic acid and solvent into the reactor and continuing the reaction;

[0022] c3) slowly adding the reaction solution of step c2) dropwise into the vigorously stirred alkaline solution and separating.

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

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

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

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

[0027] The synthetic reaction formula of the component c) is as follows:

[0028]

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

[0030] 1) Under the protection of inert gas, add component a), component b) and component c) to a reaction kettle in sequence; react at 120-180° C. for 0.2-4.0 h; preferably, react at 140-160° C. for 0.5-2.0 h;

[0031] 2) Raise the temperature to 160-240° C., maintain for 0.2-4.0 h, and detect the acid value of the product ≤ 15 mgKOH / g; preferably, raise the temperature to 180-220° C., maintain for 1.0-3.0 h;

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

[0033] 4) Devolatilizing the macromolecular polyester polyol in a scraped film evaporator, controlling the evaporator temperature to 150-250° C. and the pressure to 2-10 Pa, preferably, the evaporator temperature to 180-220° C. and the pressure to 4-8 Pa, cooling to 120° C. and discharging to obtain a low atomization value flame-retardant polyester polyol.

[0034] In the present 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 of the present invention is tetraisopropyl titanate; preferably, the amount of the catalyst added is 0-500ppm, preferably 30-300ppm, based on the total mass of the polyester polyol raw material.

[0035] The flame retardant polyester polyol of the present invention 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 the present invention, the cyclic ester refers to a macrocyclic diester formed by 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 and tested by gas chromatography-mass spectrometry (GC-MS).

[0037] In the present invention, the epoxide refers to the epoxide formed by the condensation of diol molecules during the synthesis of polyester polyols, such as the condensation of ethylene glycol molecules to form 1,4-dioxane, which is quantitatively analyzed and tested 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 a use of the polyester polyol in preparing polyurethane soft foam.

[0039] A polyurethane soft foam, obtained by reacting the following raw materials:

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

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

[0042] C: polyisocyanate: 20-28 parts by mass, preferably 22-26 parts by mass;

[0043] D: catalyst: 0.5-1.5 parts by mass, preferably 0.8-1.2 parts by mass;

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

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

[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, Bluestar 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), p-phenylene 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), hexacyclohexylmethane diisocyanate (HMDI), cyclohexane dimethylene 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 embodiments, the blowing 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 stabilize the foam. It is preferably selected from one or more of organopolysiloxanes, ethoxylated fatty alcohols, alkylphenols and castor oil esters; more preferably, it is Maitu Y-16455.

[0051] In another aspect, the present invention further provides a method for preparing the polyurethane soft foam, comprising the following steps:

[0052] 1) mixing and stirring the flame retardant polyester polyol, polyether polyol, catalyst, foaming agent, water and foam stabilizer to obtain a mixture;

[0053] 2) adding polyisocyanate to the mixture in step 1) under stirring, and then pouring into a mold at a temperature of 40 to 60° C. for natural foaming;

[0054] 3) After cooling at room temperature, place in a 40-60°C oven for 6-8 hours.

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

[0056] (1) The polyester polyol synthesized by the present invention is prepared by using dicarboxylic acid and diol containing phosphorus and nitrogen as raw materials. Phosphorus and nitrogen are simultaneously introduced into the molecular structure of the polyester polyol, which gives the polyester polyol a synergistic flame retardant property. This effectively overcomes the problem of easy precipitation and migration of current additive flame retardants, and provides support for improving the flame retardancy of polyester polyols and polyurethane soft foams.

[0057] (2) The present invention devolatilizes the synthesized macromolecular polyester polyol by a thin film evaporator to remove impurities such as residual cyclic esters and epoxides, thereby obtaining a low-fogging flame-retardant polyester polyol. The polyurethane soft foam synthesized using the low-fogging flame-retardant polyester polyol has a fogging value of less than 200 μg / g, an oxygen index of up to 27.8%, and a vertical combustion grade of V0, which meets the use requirements of the automotive industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is the hydrogen nuclear magnetic resonance spectrum analysis of C1;

[0059] Figure 2 This is the H NMR spectrum analysis of C2. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with specific embodiments. The embodiments of the present invention are only used as further explanations of the present invention and do not limit the scope of the present invention.

[0061] The main raw materials used in the preparation examples and embodiments include: TDI80 purchased from Wanhua Chemical and other companies; di(hydroxymethyl) chlorophosphate (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; Y-16455 purchased from Momentive. Unless otherwise specified, the raw materials used were obtained from commercial channels.

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

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

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

[0065] Moisture: The moisture test of polyester polyol products refers to GB / T6283-2008;

[0066] Color number: The color number test of polyester polyol products refers to GB / T3143-1982;

[0067] Cyclic ester content: The cyclic ester content of polyester polyol products is tested by quantitative analysis using gas chromatography-mass spectrometry (GC-MS);

[0068] Fogging value: The FOG value test of polyester polyol and polyurethane soft foam refers to VDA278;

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

[0070] Tensile strength and elongation at break: The tensile properties test of polyurethane soft foam refers to GB / T 6344-2008;

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

[0072] Flame retardant performance: The flame retardant performance test of polyurethane soft foam refers to GA303-2001.

[0073] Preparation Example 1

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

[0075] Add 100g of di(hydroxymethyl) chlorophosphate and 90g of tert-butyl hydroxy(methyl)carbamate to a three-necked flask in sequence, and turn on nitrogen protection. Heat the reactor to 120°C under normal pressure and maintain this temperature for 6.0h. Next, add 600mL of trifluoroacetic acid and 2.4L of dichloromethane to the reactor and maintain 40°C for 3.0h. Finally, slowly add the reaction solution dropwise to the vigorously stirred sodium carbonate solution. After the addition is completed, separate the liquids, extract the aqueous phase twice, combine the organic phases, wash the product with water, dry it, and concentrate it to obtain 76g of product C1. See attached for the hydrogen nuclear magnetic resonance spectrum analysis of C1. Figure 1 .

[0076]

[0077] Preparation Example 2

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

[0079] To a three-necked flask, add 100g of di(hydroxyethyl) chlorophosphate and 90g of tert-butyl hydroxy(methyl)carbamate in sequence, and turn on nitrogen protection. Heat the reactor to 80°C under normal pressure and maintain this temperature for 8.0h. Next, add 700mL of trifluoroacetic acid and 2.8L of dichloromethane to the reactor, and maintain 20°C for 6.0h. Finally, slowly add the reaction solution dropwise to the vigorously stirred sodium carbonate solution. After the addition is completed, separate the liquids, extract the aqueous phase twice, combine the organic phases, wash the product with water, dry it, and concentrate it to obtain 65g of product C2. The hydrogen nuclear magnetic resonance spectrum analysis of C2 is shown in Figure 2 .

[0080]

[0081] Comparative Example 1

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

[0083] 2) Then, the reactor was heated to 160°C under normal pressure and maintained at this temperature for 1 hour, and the acid value of the product was detected to be ≤15 mgKOH / g;

[0084] 3) Then, after adding 10g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was 220°C, and this temperature was maintained for 4.0h. The acid value of the product was detected to be 0.50mgKOH / g, and the hydroxyl value was 44.9mgKOH / g. The normal pressure was restored, and the temperature was lowered to 120°C to obtain 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 nitrogen atmosphere, add 5.3 kg of diethylene glycol, 0.9 kg of Cl, and 13.2 kg of adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 120°C under normal pressure and maintain this temperature for 1 hour;

[0087] 2) Then, the reactor was heated to 170°C under normal pressure and maintained at this temperature for 1 hour, and the acid value of the product was detected to be ≤15 mgKOH / g;

[0088] 3) Then, after adding 3.8g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was 185°C, and this temperature was maintained for 3.0h. The acid value of the product was detected to be 0.80mgKOH / g, and the hydroxyl value was 30mgKOH / g. The normal pressure was restored, and the temperature was lowered to 120°C to obtain 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 nitrogen atmosphere, add 7.4 kg of diethylene glycol, 16.2 kg of Cl, and 14.6 kg of adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 130°C under normal pressure and maintain this temperature for 0.5 h;

[0091] 2) Then, the reactor was heated to 190°C under normal pressure and maintained at this temperature for 2 hours, and the acid value of the product was detected to be ≤15 mgKOH / g;

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

[0093] Comparative Example 4

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

[0095] 2) Then, the reactor was heated to 220°C under normal pressure and maintained at this temperature for 3 hours, and the acid value of the product was detected to be ≤15 mgKOH / g;

[0096] 3) Then, after adding 2.1g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was 240°C, and this temperature was maintained for 5.0h. The acid value of the product was detected to be 0.9mgKOH / g, and the hydroxyl value was 40mgKOH / g. The normal pressure was restored, and the temperature was lowered to 120°C to obtain 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 nitrogen atmosphere, add 3.2 kg of diethylene glycol, 15.8 kg of C2, and 11.7 kg of adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 135°C under normal pressure and maintain this temperature for 2 hours;

[0099] 2) Then, the reactor was heated to 240°C under normal pressure and maintained at this temperature for 3 hours, and the acid value of the product was detected to be ≤15 mgKOH / g;

[0100] 3) Then, the reactor was evacuated, the reaction temperature was 240°C, and this temperature was maintained for 1.0h. The acid value of the product was detected to be 1.0mgKOH / g, and the hydroxyl value was 80mgKOH / g. The normal pressure was restored, and the temperature was lowered to 120°C to obtain a macromolecular polyester polyol with a cyclic ester content of 0.33wt%, an epoxide content of 0.22wt%, and a FOG value of 1425μg / g.

[0101] Example 1

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

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

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

[0105] 4) The macromolecular polyester polyol was devolatilized in a scraped film evaporator, and the evaporator temperature was controlled to be 150° C. and the pressure was 2 Pa. The acid value of the product was detected to be 0.30 mgKOH / g, and the hydroxyl value was 130 mgKOH / g. The product was restored to normal pressure, cooled to 120° C., and discharged to obtain a low atomization 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 nitrogen atmosphere, add 7.9 kg of diethylene glycol, 0.4 kg of Cl, and 15.3 kg of adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 165°C under normal pressure and maintain this temperature for 1.5 hours;

[0108] 2) Then, the reactor was heated to 175°C under normal pressure and maintained at this temperature for 1 hour, and the acid value of the product was detected to be ≤15 mgKOH / g;

[0109] 3) Then, 12.1 g of tetraisopropyl titanate was added, and the reactor was evacuated. The reaction temperature was set at 250°C and maintained at this temperature for 6 hours. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, and the temperature was lowered to obtain a macromolecular polyester polyol;

[0110] 4) The macromolecular polyester polyol was devolatilized in a scraped film evaporator, and the evaporator temperature was controlled to be 200° C. and the pressure was 6 Pa. The acid value of the product was detected to be 1.5 mgKOH / g, and the hydroxyl value was 140 mgKOH / g. The product was restored to normal pressure, cooled to 120° C., and discharged to obtain a low atomization 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 nitrogen atmosphere, add 10.6 kg of diethylene glycol, 8.5 kg of Cl, and 16 kg of adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 130°C under normal pressure and maintain this temperature for 3 hours;

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

[0114] 3) Then, after adding 8.1g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was 255°C, and this temperature 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 material was discharged to obtain a macromolecular polyester polyol;

[0115] 4) The macromolecular polyester polyol was devolatilized in a scraped film evaporator, and the evaporator temperature was controlled to be 220° C. and the pressure was 4 Pa. The acid value of the product was detected to be 0.6 mgKOH / g, and the hydroxyl value was 120 mgKOH / g. The product was restored to normal pressure, cooled to 120° C., and discharged to obtain a low atomization 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 nitrogen atmosphere, add 10.6 kg of diethylene glycol, 14.4 kg of Cl, and 16 kg of adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 130°C under normal pressure and maintain this temperature for 3 hours;

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

[0119] 3) Then, after adding 9.4 g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was 255°C, and this temperature was maintained for 4.5 hours. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered and the material was discharged to obtain a macromolecular polyester polyol;

[0120] 4) The macromolecular polyester polyol was devolatilized in a scraped film evaporator, and the evaporator temperature was controlled to be 250° C. and the pressure was 2 Pa. The acid value of the product was detected to be 0.4 mgKOH / g, and the hydroxyl value was 60 mgKOH / g. The product was restored to normal pressure, cooled to 120° C., and discharged to obtain a low atomization value flame retardant polyester polyol, with a cyclic ester content of 0.03wt%, an epoxide content of 0.02wt%, and a FOG value of 35μg / g.

[0121] Example 5

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

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

[0124] 3) Then, after adding 3.9g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was set at 240°C, and this temperature 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 material was discharged to obtain a macromolecular polyester polyol;

[0125] 4) The macromolecular polyester polyol was devolatilized in a scraped film evaporator, and the evaporator temperature was controlled to be 160° C. and the pressure was 9 Pa. The acid value of the product was detected to be 0.2 mgKOH / g, and the hydroxyl value was 48 mgKOH / g. The product was restored to normal pressure, cooled to 120° C., and discharged to obtain a low atomization 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 nitrogen atmosphere, add 6.4 kg of diethylene glycol, 2.0 kg of C2, and 12.4 kg of adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 155°C under normal pressure and maintain this temperature for 4 hours;

[0128] 2) Then, the reactor was heated to 180°C under normal pressure and maintained at this temperature for 4 hours, and the acid value of the product was detected to be ≤15 mgKOH / g;

[0129] 3) Then, after adding 2.1g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was set at 260°C, and this temperature 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 material was discharged to obtain a macromolecular polyester polyol;

[0130] 4) Devolatilizing the macromolecular polyester polyol in a scraped film evaporator, controlling the evaporator temperature to 230° C. and the pressure to 3 Pa. The acid value of the product was detected to be 0.7 mgKOH / g, and the hydroxyl value was 55 mgKOH / g. The product was restored to normal pressure, cooled to 120° C., and discharged to obtain a low atomization 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 nitrogen atmosphere, add 6.9 kg diethylene glycol, 17.8 kg C2, and 13.2 kg adipic acid to the reactor in sequence and stir evenly. Heat the reactor to 180°C under normal pressure and maintain this temperature for 0.2 h;

[0133] 2) Then, the reactor was heated to 200°C under normal pressure and maintained at this temperature for 0.2h. The acid value of the product was detected to be ≤15mgKOH / g;

[0134] 3) Then, after adding 9.0g of tetraisopropyl titanate, the reactor was evacuated, the reaction temperature was 240°C, and this temperature was maintained for 8h. After the acid value and hydroxyl value were qualified, the pressure was restored to normal, the temperature was lowered and the material was discharged to obtain a macromolecular polyester polyol;

[0135] 4) The macromolecular polyester polyol was devolatilized in a scraped film evaporator, and the evaporator temperature was controlled to be 240° C. and the pressure was 4 Pa. The acid value of the product was detected to be 0.9 mgKOH / g, and the hydroxyl value was 78 mgKOH / g. The product was restored to normal pressure, cooled to 120° C., and discharged to obtain a low atomization value flame retardant polyester polyol, with a cyclic ester content of 0.07wt%, an epoxide content of 0.03wt%, and a FOG value of 38μg / g.

[0136] Preparation of polyurethane soft foam 1-12

[0137] 1) According to the synthesis formula in Table 1, polyester polyol, polyether polyol, catalyst, foaming agent, water and foam stabilizer are mixed and stirred to obtain a mixture;

[0138] 2) adding polyisocyanate to the mixture in step 1) under stirring, and then pouring into a mold at a temperature of 40 to 60° C. for natural foaming;

[0139] 3) After cooling at room temperature, the mixture is placed in an oven at 40 to 60° C. for aging for 6 to 8 hours, and then the mold used for foaming the polyurethane composite material is removed to obtain a polyurethane soft foam sample.

[0140] Table 1 Formula of polyurethane soft foam 1-12 (parts by mass)

[0141]

[0142]

[0143] Performance Testing

[0144] The atomization value, density, tensile strength, elongation at break, tear strength, oxygen index and vertical burning grade of the polyurethane soft foam were measured according to the above method, and the results are shown in Table 2. From the data in the table, it can be seen that the polyurethane soft foam prepared by the low atomization value flame-retardant polyester polyol provided by the present invention has basically the same density, exhibits low atomization performance, and the lowest atomization value reaches 117μg / g. At the same time, the prepared polyurethane soft foam has excellent flame retardant properties, the oxygen index is as high as 19.7%, and the flame retardant grade can reach V0 grade, which can meet the use requirements of the automotive industry.

[0145] Analysis of polyurethane soft foam 1 and polyurethane soft foam 6-12 shows that the use of diols containing phosphorus and nitrogen as raw materials in the synthesis formula of polyester polyol can significantly improve the flame retardancy of polyurethane soft foam, and the higher the monomer ratio of nitrogen-containing diols, the more obvious the improvement of the flame retardancy of polyurethane soft foam. This is because the two elements of phosphorus and nitrogen play a synergistic flame retardant effect in the system. When the material burns, phosphorus-containing substances will also decompose to produce phosphorus-containing derivatives, which will cover the surface of the unburned substrate to form a carbon layer and isolate oxygen. At the same time, after the nitrogen element in the chain segment is decomposed by heat, it is easy to release non-combustible gases such as ammonia, nitrogen, and water vapor. These gases can take away most of the heat and reduce the surface temperature of the material.

[0146] It can be seen from the analysis of polyurethane soft foams 2-5 and polyurethane soft foams 6-12 that after synthesizing the macromolecular polyester polyol, the thin film evaporator is used to carry out devolatilization treatment, which can significantly reduce the atomization value of the macromolecular flame-retardant polyester polyol. In addition, when the evaporation temperature and vacuum degree set by the thin film evaporator are higher, it is more conducive to the evaporation of small molecules such as cyclic esters and epoxides remaining in the macromolecular flame-retardant polyester polyol, and the corresponding polyester polyol and polyurethane soft foam have better low atomization performance. The polyurethane soft foam synthesized using low atomization value polyester polyol in polyurethane soft foam 9 has a minimum atomization value of 117μg / g.

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

[0148]

[0149] The present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various 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 by comprising the following raw materials: a) dicarboxylic acid, 80-120 mol parts, preferably 90-120 mol parts; b) 50-150 mol parts, preferably 60-120 mol parts, of a nitrogen-free diol; c) Nitrogen-containing diol, 2-90 mol parts, preferably 30-80 mol parts.

2. The flame retardant polyester polyol according to claim 1, It is characterized in that In the component a), the dicarboxylic acid is selected from aliphatic carboxylic acids having 2 to 20 carbon atoms; preferably one or more selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedicarboxylic acid, hexadecanedioic acid, heptadecanedioic acid, and octadecanedicarboxylic acid.

3. The flame retardant polyester polyol according to claim 1 or 2, It is characterized in that In the component b), the nitrogen-free diol is selected from one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2-methyl-1,3-propylene glycol, 1,2-pentanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, and dipropylene glycol.

4. The flame retardant polyester polyol according to any one of claims 1 to 3, It is characterized in that In the component c), the nitrogen-containing diol has the following general structural formula: Among them, R 1 , R 2 The alkylene groups are independently C1-C8 alkylene groups, C1-C8 alkylene groups in which at least one hydrogen atom is substituted by halogen, and preferably C1-C4 alkylene groups.

5. The flame retardant polyester polyol according to any one of claims 1 to 4, It is characterized in that The component c) includes one or more of the following structural formulas:

6. The flame retardant polyester polyol according to any one of claims 1 to 5, It is characterized in that The preparation method of the component c) comprises the following steps: c1) under the protection of inert gas, di(hydroxymethyl) chlorophosphate and tert-butyl hydroxy(methyl)carbamate are added into the reactor in sequence, and the temperature is raised for reaction; c2) slowly adding trifluoroacetic acid and solvent into the reactor and continuing the reaction; c3) slowly adding the reaction solution of step c2) dropwise into the vigorously stirred alkaline solution and separating.

7. A method for preparing the flame retardant polyester polyol according to any one of claims 1 to 6, comprising the following steps: 1) Under the protection of inert gas, add component a), component b) and component c) to a reaction kettle in sequence; react at 120-180° C. for 0.2-4.0 h; preferably, react at 140-160° C. for 0.5-2.0 h; 2) Raise the temperature to 160-240° C., maintain for 0.2-4.0 h, and detect the acid value of the product ≤ 15 mgKOH / g; preferably, raise the temperature to 180-220° C., maintain for 1.0-3.0 h; 3) After adding the optional catalyst, the reactor is evacuated and maintained at 180-260° C. for 1.0-8.0 h, preferably, at 200-240° C. for 3.0-6.0 h, the acid value of the product is detected to be 0.01-5.00 mgKOH / g, and the hydroxyl value is 10-200 mgKOH / g, the pressure is restored to normal, the temperature is lowered and the material is discharged to obtain a macromolecular polyester polyol; 4) Devolatilizing the macromolecular polyester polyol in a scraped film evaporator, controlling the evaporator temperature to 150-250° C. and the pressure to 2-10 Pa, preferably, the evaporator temperature to 180-220° C. and the pressure to 4-8 Pa, cooling to 120° C. and discharging to obtain a flame-retardant polyester polyol.

8. The method according to claim 7, It is 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 0-0.5wt%, an epoxide content of 0-0.3wt%, 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 0-0.2wt%, an epoxy content of 0-0.1wt%, and a FOG value of 0-200 ug / g.

9. A polyurethane soft foam, obtained by reacting the following raw materials: A: the flame retardant polyester polyol according to any one of claims 1 to 6: 52-58 parts by mass, preferably 52-54 parts by mass; B: polyether polyol: 12-18 parts by mass, preferably 14-16 parts by mass; C: polyisocyanate: 20-28 parts by mass, preferably 22-26 parts by mass; D: catalyst: 0.5-1.5 parts by mass, preferably 0.8-1.2 parts by mass; E: foaming agent: 1.0-3.0 parts by mass, preferably 1.5-2.5 parts by mass; F: Foam stabilizer: 0.8-2.8 parts by mass, preferably 1.0-2.0 parts by mass.

10. A method for preparing the polyurethane soft foam according to claim 9, The following steps are involved: 1) mixing and stirring the flame retardant polyester polyol, polyether polyol, catalyst, foaming agent, water and foam stabilizer to obtain a mixture; 2) adding polyisocyanate to the mixture in step 1) under stirring, and then pouring into a mold at a temperature of 40 to 60° C. for natural foaming; 3) After cooling at room temperature, place in an oven at 40-60°C for 6-8 hours.

Images