Amine polyether polyols and methods for making the same

Abstract

This invention discloses amine-based polyether polyols and their preparation methods, belonging to the field of chemical synthesis technology. The technical solution includes the following steps: S1, adding a cyclohexylamine compound to a reaction vessel, purging with nitrogen, evacuating, stirring, and heating to the reaction temperature, introducing epoxides into the reaction vessel, and carrying out a polymerization reaction. After the reaction, an intermediate product is obtained; S2, adding an alkanolamine compound and an alkali metal catalyst or an amine catalyst to the intermediate product obtained in step S1, evacuating, adding epoxides, and carrying out a polymerization reaction. After the reaction, the obtained product is post-treated to obtain the amine-based polyether polyol. This invention uses cyclohexylamine compounds as the main initiator, and alkanolamine initiators can be added. Under catalytic conditions, it undergoes a segmented polymerization reaction with epoxides. The prepared special amine-based polyether polyol has the characteristics of high functionality, strong resistance to yellowing, high activity, and good thermal insulation.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, specifically to amine polyether polyols and their preparation methods. Background Technology

[0002] Polyether polyols are polymeric materials synthesized by polymerizing polyol initiators with epoxides and alkanes, and are an important class of chemical products. Polyether polyols possess excellent properties and applications, making them suitable for various industries. Their unique initiators and molecular structures contribute to their strength, toughness, and other properties, which can be used to prepare elastomers with various properties, such as flexible foams and rigid foams. Different functionalities and structures of initiator polyols lead to the synthesis of polyether polyols with different molecular weights, hydroxyl values, and viscosities, resulting in polyurethane products with varying properties such as hardness, strength, elasticity, toughness, thermal insulation, and waterproofing.

[0003] Conventional polyether polyols primarily use small-molecule polyols such as sucrose, sorbitol, propylene glycol, diethylene glycol, and glycerol as initiators. However, with the increasing demands for comprehensive properties in downstream polyurethane foams and elastomers, including resistance to yellowing, high strength, high activity, and thermal insulation, the performance of conventional polyether polyols is increasingly failing to meet these requirements. To address these needs, ethylenediamine and o-toluenediamine-based products have been developed and applied to improve relevant indicators, but their performance remains unsatisfactory. Therefore, the current development direction for polyether polyol products is to seek polyether polyols with high activity, high strength, resistance to yellowing, and low thermal conductivity. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide amine polyether polyols and their preparation methods. Cyclohexylamine compounds are used as the main initiator, and alcohol amine initiators can be added. Under catalytic conditions, the polyols undergo segmental polymerization with epoxides and alkanes. The special amine polyether polyols prepared have the characteristics of high functionality, strong resistance to yellowing, high activity, and good heat insulation.

[0005] The technical solution of this invention is as follows:

[0006] On the one hand, the present invention provides a method for preparing amine polyether polyols, comprising the following steps:

[0007] S1. Cyclohexylamine compounds are added to the reactor, purged with nitrogen, and after evacuation, the mixture is stirred and heated to the reaction temperature. Epoxy alkane is introduced into the reactor to carry out the polymerization reaction. After the reaction is completed, an intermediate product is obtained.

[0008] S2 adds an alcohol amine compound and an alkali metal catalyst or an amine catalyst to the intermediate product obtained in step S1. After vacuuming, an epoxide alkane is added to carry out a polymerization reaction. After the reaction is completed, the obtained product is post-treated to obtain an amine polyether polyol.

[0009] Preferably, in step S1, the cyclohexylamine compound is one or two of 3-aminomethylcyclohexylamine, 1-(4-aminocyclohexyl)urea, and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane.

[0010] Preferably, in step S2, the amine compound is one or more of diethanolamine, triethanolamine, and isopropanolamine.

[0011] Preferably, in step S2, the alkali metal catalyst is potassium hydroxide or sodium hydroxide; the amine catalyst is 2,4,6-tris(dimethylaminomethyl)phenol or triethylamine.

[0012] Preferably, in steps S1 and S2, the epoxide is one or more of ethylene oxide, butane oxide, and propylene oxide.

[0013] Preferably, the amounts of each raw material added are as follows by mass, wherein the amounts of amine catalyst and alkali metal catalyst added are not both 0:

[0014]

[0015] Preferably, in step S1, the polymerization reaction temperature is 85-95℃, the reaction pressure is <0.4MPa, and the reaction time is 2-4h.

[0016] Preferably, in step S2, the polymerization reaction temperature is 105-125℃, the reaction pressure is <0.4MPa, and the reaction time is 2-4h.

[0017] Preferably, in step S2, the specific post-treatment process is as follows: if the catalyst is an amine catalyst, the reaction is directly degassed and bubbled for 2-4 hours, then cooled and discharged; if the catalyst is an alkali metal catalyst, an aqueous solution of phosphoric acid is added to the obtained crude polyether polyol, and the mixture is stirred at 80-90℃ for 0.5-1 hours for neutralization. After neutralization, an adsorbent is added, and the mixture is stirred at 80-90℃ for 0.5-1 hours for adsorption. After adsorption, the mixture is dehydrated, dried, and filtered under reduced pressure to obtain the amine polyether polyol.

[0018] On the other hand, the present invention provides amine polyether polyols, which are prepared by the above preparation method.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This invention uses cyclohexylamine compounds as the main initiator, and can add alkanolamine initiators. Under catalytic conditions, it undergoes a segmented polymerization reaction with epoxide alkane to prepare a special amine polyether polyol with high functionality, strong resistance to yellowing, high activity, and good thermal insulation. It can significantly improve the yellowing resistance, strength, flowability, and thermal insulation of downstream polyurethane foam. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0022] Example 1

[0023] The preparation method of the amine polyether polyol in this embodiment includes the following steps:

[0024] S1. Add 128g of 3-aminomethylcyclohexylamine to the reactor, purge with nitrogen, pressurize and test for leaks, then evacuate the reactor to -0.09MPa, start stirring, heat to 85℃, slowly introduce 390g of propylene oxide, and maintain the pressure below 0.4MPa during this period. After the feed is completed, react at this temperature and pressure for 2 hours.

[0025] S2 adds 105g of diethanolamine and 8g of solid potassium hydroxide to the reactor, evacuates the reactor to -0.09MPa, and slowly introduces 1987g of propylene oxide, maintaining the pressure below 0.4MPa and the temperature at 115℃. After the feed is complete, the reaction is carried out at this temperature and pressure for 3 hours to obtain crude polyether polyol. Finally, a mixed solution of 18.8g of phosphoric acid and 130g of pure water is added at 80℃ for neutralization reaction. After reacting for 1 hour, 2.6g of magnesium silicate and 1.3g of aluminum silicate adsorbent are added. After stirring for 40 minutes, the mixture is dehydrated and dried for 4.5 hours. After drying, it is filtered to obtain refined amine polyether polyol.

[0026] Example 2

[0027] The preparation method of the amine polyether polyol in this embodiment includes the following steps:

[0028] S1. Add 157g of 1-(4-aminocyclohexyl)urea to the reactor, purge with nitrogen, pressurize and test for leaks, then evacuate the reactor to -0.09MPa, start stirring, heat to 85℃, slowly introduce 85g of propylene oxide, and maintain the pressure below 0.4MPa during this period. After the feed is complete, react at this temperature and pressure for 2 hours.

[0029] S2 adds 7g of catalyst 2,4,6-tris(dimethylaminomethyl)phenol to the reactor, evacuates the reactor to -0.09MPa, and slowly introduces 451g of propylene oxide, maintaining the pressure below 0.4MPa and the temperature at 115℃. After the feed is complete, the reaction is carried out at this temperature and pressure for 3 hours to obtain crude polyether polyol. After the reaction is complete, the product is degassed and dried for 1.5 hours, cooled and discharged to obtain refined amine polyether polyol.

[0030] Example 3

[0031] The preparation method of the amine polyether polyol in this embodiment includes the following steps:

[0032] S1. Add 210g of 4,4'-diaminodicyclohexylmethane to the reactor, purge with nitrogen, and after pressure testing, evacuate the reactor to -0.09MPa, start stirring, raise the temperature to 85℃, and slowly introduce 190g of propylene oxide, maintaining the pressure below 0.4MPa during this period. After the feed is completed, react at this temperature and pressure for 2 hours.

[0033] S2 adds 150g of triethanolamine and 2g of 2,4,6-tris(dimethylaminomethyl)phenol to the reactor, evacuates the reactor to -0.09MPa, and slowly introduces 759g of propylene oxide, maintaining the pressure below 0.4MPa and the temperature at 115℃. After the feed is complete, the reaction is carried out at this temperature and pressure for 3 hours to obtain crude polyether polyol. After the reaction is complete, the product is degassed and dried for 2.5 hours, cooled and discharged to obtain refined amine polyether polyol.

[0034] Comparative Example 1

[0035] The preparation method of the polyether polyol in Comparative Example 1 is as follows:

[0036] After the reactor is pressurized and leak tested, nitrogen is used for purging. The reactor is then evacuated to -0.09 MPa, stirring is started, 60 g of ethylenediamine is added to the reactor, the temperature is raised to 85°C, and 240 g of propylene oxide is slowly introduced while maintaining the pressure below 0.4 MPa. After the feeding is completed, the reactor is reacted at this temperature and pressure for 2 hours.

[0037] The temperature was then raised to 105℃, and 105g of diethanolamine and 8g of solid potassium hydroxide were added to the reactor under negative pressure. The reactor was then evacuated to -0.09MPa, and 2205g of propylene oxide was slowly introduced, maintaining the pressure below 0.4MPa and the temperature at 115℃. After feeding, the mixture was pressurized at this temperature and pressure for 3 hours to obtain crude polyether polyol. Finally, a mixed solution of 14g of phosphoric acid and 130g of pure water was added at 80℃ for neutralization. After reacting for 1 hour, 2.61g of magnesium silicate and 1.30g of aluminum silicate adsorbent were added. After stirring for 40 minutes, the mixture was dehydrated and dried for 3.5 hours. After drying, the purified polyether polyol was obtained by filtration.

[0038] Comparative Example 2

[0039] The preparation method of the polyether polyol in Comparative Example 2 is as follows:

[0040] 325g sucrose, 50g solid sorbitol, 80g diethylene glycol, 255g palm oil, and 12g fatty amine catalyst were added to a reactor. After leak testing and purging, the reactor was heated to 105℃ under negative pressure, and 787g propylene oxide was added dropwise. At the same time, the nitrogen atmosphere pressure inside the reactor was maintained at 0.13±0.02MPa. After the propylene oxide was added, the reaction was kept at this temperature for 3 hours until the pressure inside the reactor no longer decreased. After bubbling to remove monomers for 2 hours, the temperature was lowered to 80℃, and the polyether polyol was discharged.

[0041] The testing standards and methods used for polyether polyols are as follows:

[0042] Hydroxyl value: Tested according to GB / T 12008.3-1989 "Determination of hydroxyl value in polyether polyols";

[0043] Viscosity: Tested in accordance with GB / T 12008.7-2010 "Plastics Polyether Polyols Part 7: Determination of Viscosity".

[0044] The performance of the polyether polyols prepared in Examples 1-3 and Comparative Examples 1-2 was tested, and the results are shown in Table 1.

[0045] Table 1. Performance test results of the polyether polyols prepared in Examples 1-3 and Comparative Examples 1-2.

[0046]

[0047] The polyether activity of Examples 1-3 and Comparative Examples 1-2 was verified by foaming the mixtures prepared according to the table below.

[0048] Table 2. Activity test results of the polyether polyols prepared in Examples 1-3 and Comparative Examples 1-2

[0049] Components Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Polyether polyol g 100 100 100 100 100 Foaming agent g 2 2 2 2 2 catalyst g 1 1 1 1 1 water g 1 1 1 1 1 141B g 25 25 25 25 25 Active s 125 87 80 156 110

[0050] As shown in Table 2, under the same foaming system, Example 1 showed a 31-second faster activity compared to Comparative Example 1, and Example 2 showed a 23-second faster activity compared to Comparative Example 2. Similarly, Example 3 showed a significantly faster activity compared to conventional polyethers (Comparative Examples 1 and 2). The main reasons are: firstly, amino-containing initiators have higher activity than polyethers started with conventional small-molecule polyols such as sucrose and sorbitol; secondly, this invention uses cyclohexylamine initiators with a functionality of 4-5, and under the special structural conditions of the initiator, due to steric hindrance, the number of epoxides hydrogenated by each amino group differs considerably when epoxides are attached, resulting in significant differences in their activity.

[0051] The polyether polyols prepared in Examples 1-3 and Comparative Examples 1-2 were formulated according to the formulations shown in Table 3 to prepare rigid polyurethane foam samples and their properties were tested. The test results are shown in Table 3.

[0052] Table 3. Formulations and performance test results of rigid polyurethane foam samples from Examples 1-3 and Comparative Examples 1-2.

[0053]

[0054]

[0055] The preparation method of rigid polyurethane foam samples is as follows: Under the conditions of ambient temperature 25℃ and mold temperature 45℃, accurately weigh each component according to the formula in Table 2, and prepare a composite material in a 500mL beaker. Take 50 parts of the above composite material and 50 parts of isocyanate PM200 and stir thoroughly. Stop stirring when the system is uniform. Pour the stirred material into a constant temperature foaming mold. After the foam has foamed, matured and cured, remove it from the mold to obtain a rigid polyurethane foam sample. Among them, the foaming agent in Table 2 is Nanjing Meiside Chemical S-8805, the catalyst is Evonik Specialty Chemicals (Shanghai) Co., Ltd. PC-8, and 141B is the foaming agent monofluorodichloroethane. All of the above products are commercially available products.

[0056] The performance of the above rigid polyurethane foam samples was tested according to the following standards and methods, and the test results are shown in Table 4-5:

[0057] Thermal conductivity: The rigid polyurethane foam sample was cut into 20cm×20cm×2.5cm blocks and thermal conductivity was tested. The test method was in accordance with GB / T 10295-2008 "Determination of steady-state thermal resistance and related properties of thermal insulation materials - heat flow meter method".

[0058] Yellowing resistance: The rigid polyurethane foam sample was cut into 10cm×10cm×10cm pieces and placed in an ultraviolet aging chamber to observe the degree of yellowing after different times of ultraviolet irradiation.

[0059] Table 4. Thermal conductivity test results of rigid polyurethane foam samples

[0060]

[0061] Table 5 Results of yellowing resistance test of rigid polyurethane foam samples

[0062]

[0063]

[0064] As shown in Table 3, compared with Comparative Example 1, the rigid polyurethane foam sample of Example 1 showed an increase in strength of over 20% and a flowability increase of approximately 1.2%. This is mainly because, under conditions where the functionality of the polyether is essentially the same, the structure of the cyclohexylamine-containing raw material provides better strength compared to the conventional ethylenediamine molecular structure.

[0065] Compared to Comparative Example 2, the rigid polyurethane foam sample of Example 2 showed an increase in strength of over 15% and an increase in flowability of approximately 7.9%. This is because the polyether synthesized from conventional polyols typically has a functionality of around 4, fewer rigid ring structures, and the addition of oil-based raw materials reduces costs and increases miscibility. The functionality of Example 2 is lower than that of Example 2, and it generally contains oil, significantly reducing foam strength.

[0066] Furthermore, as shown in Table 4, the thermal conductivity of the rigid polyurethane foam samples in Examples 1-3 is significantly higher than that in Comparative Examples 1-2; as shown in Table 5, the yellowing resistance of the rigid polyurethane foam samples in Examples 1-2 is also significantly better than that in Comparative Examples 1-2. This is because current polyether polyols use initiators containing more amino groups, resulting in a more uniform and dense foam cell structure and reduced thermal conductivity; at the same time, they all have saturated alicyclic structures, providing some rigidity while the stable structure makes the product less prone to oxidation, increasing antioxidant properties and resulting in better yellowing resistance.

Claims

1. Process for the preparation of amine polyether polyols, characterized in that, Includes the following steps: S1. Cyclohexylamine compounds are added to a reaction vessel, purged with nitrogen, and after evacuation, stirred and heated to the reaction temperature. Epoxy alkane is then introduced into the reaction vessel to carry out a polymerization reaction. The polymerization reaction temperature is 85-95℃, the reaction pressure is <0.4MPa, and the reaction time is 2-4h. After the reaction is completed, an intermediate product is obtained. The cyclohexylamine compounds are one or two of 3-aminomethylcyclohexylamine, 1-(4-aminocyclohexyl)urea, and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane. S2. Add an alkanolamine compound and an alkali metal catalyst or an amine catalyst to the intermediate product obtained in step S1. After vacuuming, add epoxide alkane to carry out a polymerization reaction. The polymerization reaction temperature is 105-125℃, the reaction pressure is <0.4MPa, and the reaction time is 2-4h. After the reaction is completed, the obtained product is post-treated to obtain an amine polyether polyol. The alkanolamine compound is one or more of diethanolamine, triethanolamine, and isopropanolamine. The amounts of each raw material added, by mass, are as follows, where the amounts of amine catalyst and alkali metal catalyst added are both 0: Cyclohexylamine compounds 4-25 parts 0-12 parts of alcohol amine compounds 0-1 part of amine catalyst Alkali metal catalyst 0-0.35 parts 70-95 parts of epoxides.

2. The method for preparing amine polyether polyols as described in claim 1, characterized in that, In step S2, the alkali metal catalyst is potassium hydroxide or sodium hydroxide; the amine catalyst is 2,4,6-tris(dimethylaminomethyl)phenol or triethylamine.

3. The method for preparing amine polyether polyols as described in claim 1, characterized in that, In steps S1 and S2, the epoxide is one or more of ethylene oxide, butane oxide, and propylene oxide.

4. The method for preparing amine polyether polyols as described in claim 1, characterized in that, In step S2, the specific post-treatment process is as follows: If the catalyst is an amine catalyst, the reaction can be directly degassed, bubbled, cooled, and discharged; if the catalyst is an alkali metal catalyst, an aqueous solution of phosphoric acid is added to the obtained crude polyether polyol, and the mixture is stirred at 80-90℃ for 0.5-1h for neutralization. After neutralization, an adsorbent is added, and the mixture is stirred at 80-90℃ for 0.5-1h for adsorption. After adsorption, the mixture is dehydrated, dried, and filtered under reduced pressure to obtain the amine polyether polyol.

5. An amine-based polyether polyol characterized in that, It is prepared by the preparation method according to any one of claims 1-4.

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