Flame-retardant polyether ester polyol and preparation method thereof

Abstract

The invention discloses flame-retardant polyether ester polyol with a structure shown in a formula I and a preparation method of the flame-retardant polyether ester polyol. The preparation method comprises the following steps: (1) adding polyether polyol and dicarboxylic acid, and carrying out esterification reaction; (2) continuing to add dihydric alcohol and a catalyst, and carrying out esterification reaction; and (3) finally adding melamine resin CN-3360 to carry out esterification reaction, and carrying out reduced pressure distillation to obtain the flame-retardant polyether ester polyol. The melamine resin molecular structure is introduced into the polyether ester polyol, so that the flame retardant polyether ester polyol has flame retardant property, does not contain halogen, and is safe and environment-friendly. # imgabs0 #

Description

Technical Field

[0001] The invention relates to a polymer compound, in particular to a flame retardant polyether ester polyol and a preparation method thereof. Background Art

[0002] In the development of modern plastics industry, polyurethane materials are widely used as thermal insulation and structural materials in household appliances, petrochemicals, construction, aviation, mechanical instruments, etc. due to their excellent thermal insulation, electrical insulation, sound insulation, chemical corrosion resistance and other properties. Oligomer polyols are one of the basic raw materials for synthesizing polyurethane, and their research and development is a key factor affecting the development of the polyurethane industry.

[0003] Oligomer polyols mainly include polyether polyols and polyester polyols, but each has its own advantages and disadvantages. In order to make up for this deficiency, two special oligomer polyols: polyether ester polyols and polymer polyester polyols have been developed. The polyether ester polyurethane materials prepared by them have both the low temperature resistance and hydrolysis resistance of polyether polyurethane materials and the high heat resistance and mechanical properties of polyester polyurethane materials. More importantly, the production cost of polyurethane materials is reduced. Polymer polyester polyols are a modified polyester polyol that can improve the thermal stability, water resistance and mechanical properties of polyester polyurethane materials. Therefore, polyether ester polyols and polymer polyester polyols are considered to be the hot spots of oligomer polyol research at present, and their synthesis and the development of corresponding new materials are also receiving more and more attention in the industry.

[0004] Polyetheresters are made of polyester as a hard segment to provide rigidity to the polymer and polyether as a soft segment to provide elasticity to the polymer. Due to its special and excellent thermophysical and mechanical properties, it is increasingly used in daily life. However, polyetheresters were initially developed for use in the textile industry to prepare highly elastic fibers. Today, they are also widely used in transportation equipment parts, sports equipment, and even in biomedical materials. The hardness of polyetherester materials is between that of vulcanized rubber and plastic. Compared with rubber, it has better processing properties, and compared with plastic, it has better flexibility and dynamic mechanical properties. In addition, due to its good mechanical properties, toughness, and stable electrical insulation properties, it has significant application value in molded soles, ski boots, automotive parts, wires and cables, shock absorbers, and biomedicine. However, existing polyetherester polyols do not have flame retardant properties. Summary of the invention

[0005] Object of the invention: The first object of the present invention is to provide a polyether ester polyol having flame retardant properties; the second object of the present invention is to provide a method for preparing the polyether ester polyol.

[0006] The flame retardant polyether ester polyol of the present invention has the following structure:

[0007]

[0008] Where R is (OCH2CH2) n or [OCH2CH2(CH3)] n , n=2~4; R1 is (CH2) 1～3 、(CH2) 1～3 O(CH2) 1～3 , CH2CH(CH3) or CH2CH(CH3)OCH2CH(CH3); R2 is (CH2) m , m=4~8.

[0009] Preferably, R1 is (CH2)2 or CH2CH2OCH2CH2.

[0010] The method for preparing the flame retardant polyether ester polyol of the present invention comprises the following steps:

[0011] (1) adding polyether polyol and dicarboxylic acid to carry out esterification reaction;

[0012] (2) continuing to add diol and catalyst to carry out esterification reaction;

[0013] (3) Finally, melamine resin CN-3360 is added to carry out esterification reaction, and vacuum distillation is performed to obtain flame retardant polyether ester polyol.

[0014] The basic synthesis process of polyether ester polyols is divided into a monomer method and a polymer method, wherein the monomer method mainly includes a hydroxyl-terminated polyether method and an acetoxy-terminated polyether method, and the polymer method refers to a chain exchange method that directly uses macromolecular polyester and polyether as raw materials. One of the more commonly used methods is to use a low molecular weight hydroxyl-terminated polyether and a polyester monomer for condensation synthesis at high temperature. The present invention adopts a step-by-step reaction method, firstly, the polyether is esterified with a dicarboxylic acid, and then a small molecule polyol and a melamine resin are added for esterification reaction and termination, to obtain a hydroxyl-terminated flame-retardant polyether ester polyol, and a special product molecular structure can be designed by adjusting the reaction steps and raw materials.

[0015] Preferably, in step (1), the temperature of the esterification reaction is 120-130° C., and the reaction time is 2-4 hours.

[0016] Preferably, in step (1), the molar ratio of the polyether polyol to the dicarboxylic acid is 1:2.95-3.0.

[0017] Preferably, the dicarboxylic acid is at least one selected from adipic acid, azelaic acid, and sebacic anhydride.

[0018] Preferably, polyether polyol CHE-307.

[0019] Preferably, in step (2), the temperature of the esterification reaction is 200-250° C., and the reaction time is 3-5 h.

[0020] Preferably, in step (2), the molar ratio of the diol to the polyether polyol is 2.0 to 2.1:1.

[0021] Preferably, in step (2), during the esterification reaction, the top temperature of the condenser is observed and controlled to be 100±2°C.

[0022] The diol is selected from at least one of ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol; and the catalyst is selected from tetrabutyl titanate or isobutyl titanate.

[0023] Preferably, in step (3), the reduced pressure distillation is: when the top temperature is lower than 50°C, the reduced pressure distillation is started, and the vacuum gradient is increased. In terms of gauge pressure, the reduced pressure distillation is performed at -0.03MPa, -0.05MPa, and -0.08MPa for 1 to 2h, respectively, and finally the reduced pressure distillation is performed at a vacuum degree of not less than -0.095MPa until the acid value is less than 1.0mg KOH / g.

[0024] Invention mechanism: The present invention provides a flame retardant polyether ester polyol, which first reacts with one of the carboxyl groups of a dicarboxylic acid through an esterification reaction, and then reacts with another carboxyl group of the dicarboxylic acid after adding a small molecule diol and a terminal hydroxyl group to a melamine resin, and introduces a melamine resin molecular structure into the polyether ester polyol under the action of a catalyst. Melamine resin contains rich flame retardant elements N and triazine ring structures, and has excellent flame retardant effects. If used in combination with a flame retardant containing phosphorus elements, the flame retardant effect is even better. The product does not contain halogens, is safe and environmentally friendly, and has achieved good technical effects.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) By introducing melamine resin into polyester polyol, the polyester polyol has flame retardant properties, is halogen-free, safe and environmentally friendly; (2) ethylene oxide and propylene oxide are not used as raw materials, and pressure vessels and other equipment are not required, so the equipment investment is simple. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific embodiments.

[0027] Example 1

[0028] The flame retardant polyether ester polyol of the present invention has the following structural formula:

[0029]

[0030] The preparation method comprises the following steps in sequence:

[0031] (1) Polyether polyol CHE-307 (Changhua Chemical Technology Co., Ltd.) and adipic acid were added in a molar ratio of 1:2.95 in a 3 L stainless steel polyester reactor;

[0032] (2) Nitrogen replacement was performed 6 times, the valve was closed, and heating was started, and the temperature was raised to 130°C for reaction for 3 hours;

[0033] (3) Add 1,2-propylene glycol and tetrabutyl titanate in a molar ratio of CHE-307:1,2-propylene glycol = 1:2.01, and a catalyst dosage of 150 ppm. Open the tail gas valve, and heat to 220°C while continuing to flow nitrogen to continue the reaction.

[0034] (4) Observe the top temperature of the condenser and control it at 100±2℃;

[0035] (5) After 4 h of reaction, melamine resin CN-3360 (Jiangsu Changneng Energy Saving New Materials Technology Co., Ltd.) was added at a molar ratio of CHE-307:CN-3360=1:1;

[0036] (6) When the top temperature is lower than 50° C., vacuum distillation is started, and the vacuum degree gradient is increased. The vacuum distillation is performed at -0.03 MPa, -0.05 MPa, and -0.08 MPa for 1 h, respectively. Finally, the vacuum distillation is performed at a vacuum degree of not less than -0.095 MPa until the acid value is less than 1.0 mgKOH / g, and then the material is discharged and packaged to obtain a flame retardant polyether ester polyol.

[0037] Embodiments 2 to 5

[0038] Examples 2 to 5 and Comparative Example 1 were carried out according to the steps in Example 1, except for the differences in reaction raw materials, raw material ratios, reaction time, and reaction temperature, as shown in Table 1.

[0039] The flame retardant polyether ester polyol prepared in Example 2 has the following structural formula:

[0040]

[0041] The flame retardant polyether ester polyol prepared in Example 3 has the following structural formula:

[0042]

[0043] The flame retardant polyether ester polyol prepared in Example 4 has the following structural formula:

[0044]

[0045] The flame retardant polyether ester polyol prepared in Example 5 has the following structural formula:

[0046]

[0047] The product structural formula of Comparative Example 1 is as follows:

[0048]

[0049] Table 1 Molar ratio of raw materials and reaction conditions in Examples 1 to 5 and Comparative Example 1

[0050]

[0051] Performance Testing

[0052] The moisture content, viscosity, hydroxyl value and acid value of the flame retardant polyether ester polyols of Examples 1 to 5 and the product prepared in Comparative Example 1 were tested. The flame retardant polyether ester polyols prepared in Examples 1 to 5 and the product prepared in Comparative Example 1 were used to prepare polyurethane soft foams, the formula of which is shown in Table 2, and the flame retardant properties thereof were tested. The test results are shown in Table 3.

[0053] Table 3 Polyurethane soft foam formula

[0054] Raw material name Mass fraction PPG 50 POP 30 Flame retardant polyetherester polyol 20 <![CDATA[H2O]]> 3.2 Silicone oil 0.9 Catalyst 0.38 Fire Replenishing Agent 3.5 TDI 47.5

[0055] Table 3 Index data of flame retardant polyether ester polyols prepared in Examples 1 to 5

[0056]

[0057] As can be seen from Table 2, the flame retardant polyether ester polyols prepared in Examples 1 to 5 and the comparative example have acid values ​​lower than 1 mg KOH / g, indicating that the reaction degree is relatively high. The oxygen index of the product prepared by adding the flame retardant polyether ester polyol to the polyurethane soft foam formula is increased by more than 10% compared with the comparative example, achieving good technical effects.

Claims

1. A flame retardant polyetherester polyol, characterized in that: Its structure is as follows: Where R is (OCH2CH2) n or [OCH2CH2(CH3)] n , n=2~4; R1 is (CH2) 1～3 、(CH2) 1～3 O(CH2) 1～3 , CH2CH(CH3) or CH2CH(CH3)OCH2CH(CH3); R2 is (CH2) m , m=4~8.

2. The flame retardant polyetherester polyol according to claim 1, characterized in that: The R1 is (CH2)2 or CH2CH2OCH2CH2.

3. A method for preparing the flame retardant polyether ester polyol according to claim 1 or 2, characterized in that: The following steps are involved: (1) adding polyether polyol and dicarboxylic acid to carry out esterification reaction; (2) continuing to add diol and catalyst to carry out esterification reaction; (3) Finally, melamine resin CN-3360 is added to carry out esterification reaction, and vacuum distillation is performed to obtain flame retardant polyether ester polyol.

4. The method for preparing the flame retardant polyether ester polyol according to claim 3, characterized in that: In step (1), the temperature of the esterification reaction is 120-130°C.

5. The method for preparing the flame retardant polyether ester polyol according to claim 3, characterized in that: In step (1), the molar ratio of the polyether polyol to the dicarboxylic acid is 1:2.95-3.

0.

6. The method for preparing the flame retardant polyether ester polyol according to claim 3, characterized in that: In step (2), the temperature of the esterification reaction is 200-250°C.

7. The method for preparing the flame retardant polyether ester polyol according to claim 3, characterized in that: In step (2), the molar ratio of the diol to the polyether polyol is 2.0 to 2.1:

1.

8. The method for preparing the flame retardant polyether ester polyol according to claim 3, characterized in that: In step (3), the reduced pressure distillation is as follows: when the top temperature is lower than 50° C., the reduced pressure distillation is started, the vacuum degree gradient is increased, and the reduced pressure distillation is performed at -0.03 MPa, -0.05 MPa, and -0.08 MPa for 1 to 2 hours, respectively, and finally the reduced pressure distillation is performed at a vacuum degree not lower than -0.095 MPa until the acid value is less than 1.0 mg KOH / g.

9. The method for preparing a flame retardant polyether ester polyol according to claim 3, characterized in that: In step (2), during the esterification reaction, the top temperature of the condenser is observed and controlled to be 100±2°C.

10. The method for preparing the flame retardant polyether ester polyol according to claim 3, characterized in that: The dicarboxylic acid is selected from at least one of adipic acid, azelaic acid, and sebacic anhydride; the diol is selected from at least one of ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; and the catalyst is selected from tetrabutyl titanate or isobutyl titanate.

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