High pentane miscible polyether polyol and preparation method thereof

Abstract

The present invention belongs to the technical field of polyether polyols, and specifically relates to a polyether polyol with high pentane miscibility and a preparation method thereof. The polyether polyol is composed of the following raw materials in parts by mass: 9 to 23 parts of small molecule polyols; 0.5 to 2.5 parts of amine catalysts; 12 to 43 parts of polyhydroxy stearates; and 47 to 66 parts of alkylene oxides. Polyhydroxy stearates are used as composite initiators, and through molecular structure design, polyhydroxy-rich fatty long chains are introduced into the molecular skeleton of polyether polyols, which significantly enhances the miscibility of polyether polyols with pentane. In addition, the polyhydroxy stearates also contain a large number of hydroxyl groups, which can directly participate in the polymerization reaction and firmly bond to the main chain of the polyether polyol, which not only optimizes the storage stability of the product, but also significantly improves its functionality and hydroxyl value, and verifies the high strength characteristics of the product in practical applications.

Description

Technical Field

[0001] The invention belongs to the technical field of polyether polyols, and particularly relates to high-pentane miscible polyether polyols and a preparation method thereof. Background Art

[0002] With F11 banned and 141b phased out, pentane foaming agents, as new foaming agents for rigid polyurethane foam, have been widely used in the fields of fluorine-free refrigerators, freezers, cold storage, pipeline insulation, etc. However, the solubility challenges of this type of foaming agent in polyether polyol systems, especially the compatibility defects with certain types of polyols (such as phthalic anhydride polyester polyols), limit their promotion and use in certain specific application scenarios.

[0003] To overcome this limitation, research focuses on optimizing the performance of polyether polyols through molecular structure design. Specific strategies include cleverly introducing natural plant oils rich in long-chain fat structures such as palm oil and soybean oil into the molecular chain of polyether polyols, aiming to significantly improve their miscibility by promoting the interaction between polyether polyols and pentane foaming agents. The core of this improvement process is that the introduction of plant oils can induce a small amount of transesterification reaction, thereby achieving effective fusion of the two at the molecular level. However, this combination method will result in limited addition of plant oils and poor storage stability. In addition, because plant oils themselves do not provide effective functionality, large-scale introduction will have a significant impact on the performance of polyether polyols such as product strength. Summary of the invention

[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a polyether polyol with high pentane miscibility, using polyhydroxy stearate as a composite initiator, introducing a polyhydroxy-rich fatty long chain into the molecular skeleton of the polyether polyol through molecular structure design, and significantly enhancing the miscibility of the polyether polyol with pentane. In addition, the polyhydroxy stearate also contains a large number of hydroxyl groups, which can directly participate in the polymerization reaction and firmly bond to the main chain of the polyether polyol, which not only optimizes the storage stability of the product, but also significantly improves its functionality and hydroxyl value, and verifies the high strength characteristics of the product in practical applications.

[0005] Another object of the present invention is to provide a method for preparing a polyether polyol with high pentane miscibility, which has a simple process and is easy for large-scale production.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The high pentane miscible polyether polyol is composed of the following raw materials in parts by weight:

[0008] Small molecule polyol: 9~23 parts;

[0009] Amine catalyst: 0.5~2.5 parts;

[0010] Polyhydroxy stearate: 12-43 parts;

[0011] Alkylene oxide: 47-66 parts.

[0012] The small molecule polyol is one or more of sucrose, sorbitol, glycerol, diethylene glycol, propylene glycol or pentaerythritol.

[0013] The amine catalyst is one or more of dimethylamine, trimethylamine or N,N-dimethylcyclohexylamine.

[0014] The polyhydroxy stearate is one or more of sucrose stearate or sorbitan monostearate.

[0015] The alkylene oxide is one or more of ethylene oxide, propylene oxide or butylene oxide.

[0016] The preparation method of the high pentane miscible polyether polyol comprises the following steps:

[0017] (1) adding a small molecule polyol and a first portion of an amine catalyst into a reaction kettle, replacing with nitrogen, heating, and then adding the first portion of an alkylene oxide for addition reaction to obtain a polyether intermediate;

[0018] (2) Add polyhydroxy stearate and the second part of amine catalyst to the polyether intermediate, replace with nitrogen, and add the second part of alkylene oxide after initial heating to carry out polymerization reaction. After the reaction is completed, heat again and add the third part of alkylene oxide to continue the reaction. After the reaction is completed, a high pentane miscible polyether polyol is obtained.

[0019] The amount of the first part of the amine catalyst added is 50-80 wt.% of the total amount of the amine catalyst.

[0020] The amount of the first-stage alkylene oxide added is 10-20 wt.% of the total amount of the alkylene oxide; the amount of the second-stage alkylene oxide added is 5-10 wt.% of the total amount of the alkylene oxide.

[0021] In the step (1), the reaction temperature of the addition reaction is 90-120°C.

[0022] In the step (2), the reaction temperature of the polymerization reaction after adding the second stage of alkylene oxide is 80-90°C; the reaction temperature of the continued reaction after adding the third stage of alkylene oxide is 100-120°C.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The high pentane miscible polyether polyol of the present invention uses polyhydroxy stearate as a composite initiator. This compound can significantly enhance the miscibility between the polyether polyol and pentane due to its unique long-chain fatty structure, thus bringing convenience and efficiency improvement to the material processing and application process;

[0025] (2) The high pentane miscible polyether polyol of the present invention adopts polyhydroxy stearate as an initiator. Its abundant hydroxyl groups can not only effectively participate in the polymerization reaction and firmly bind to the main chain of the polyether polyol, but also significantly enhance the storage stability of the polyether polyol compared to traditional vegetable oils and fats that only participate through limited transesterification. More importantly, the high compatibility of the initiator allows a significant increase in its addition amount in the formulation components without causing turbidity in the polyether system, thus ensuring the stability of the product performance;

[0026] (3) The high pentane miscible polyether polyol of the present invention uses polyhydroxy stearate as an initiator. The large amount of hydroxyl groups provided by the polyol itself improves the functionality and hydroxyl value of the product. The application of the polyurethane rigid foam in the field can effectively overcome the problem of strength performance degradation caused by the introduction of vegetable oils in the past, and achieves the improvement of mechanical properties.

[0027] (4) The method for preparing the high pentane miscible polyether polyol of the present invention adopts a staged synthesis process, which enhances the compatibility between the components of the raw material system, not only improves the storage stability of the product, but also ensures the controllability of the production process and the stability of the product quality, and is easy to scale up production. DETAILED DESCRIPTION

[0028] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0029] The raw materials used in the examples and comparative examples are conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0030] Example 1

[0031] The preparation method of the high pentane miscible polyether polyol comprises the following steps:

[0032] (1) 90 g of sucrose, 10 g of propylene glycol and 5 g of dimethylamine were added to a reactor, replaced with nitrogen, evacuated to -0.09 MPa, stirred and heated to 90°C, 24 g of ethylene oxide was slowly added, and the reaction was kept warm for 5 hours. The pressure of the reactor was maintained below 0.35 MPa to obtain a polyether intermediate;

[0033] (2) Add 100 g of sorbitan monostearate and 5 g of dimethylamine to the polyether intermediate. After nitrogen replacement, evacuate the reactor to -0.09 MPa, initially heat it to 80°C, slowly add 12 g of propylene oxide to carry out polymerization reaction, and after the reaction is completed, heat it again to 120°C, slowly add 204 g of propylene oxide and continue the reaction for 5 h. The pressure in the reactor is maintained below 0.35 MPa. After the reaction is completed, evacuate to -0.08 MPa, bubble nitrogen for 30 min, cool to 90°C, and discharge the material to obtain a polyether polyol with high pentane miscibility.

[0034] Example 2

[0035] The preparation method of the high pentane miscible polyether polyol comprises the following steps:

[0036] (1) 15 g of propylene glycol, 30 g of diethylene glycol and 2 g of N,N-dimethylcyclohexylamine were added to a reactor, replaced with nitrogen, evacuated to -0.09 MPa, stirred and heated to 120°C, 44 g of butylene oxide was slowly added, and the reaction was kept warm for 0.5 h. The pressure of the reactor was maintained below 0.35 MPa to obtain a polyether intermediate;

[0037] (2) Add 200 g of sucrose stearate and 0.5 g of N,N-dimethylcyclohexylamine to the polyether intermediate. After nitrogen replacement, evacuate the reactor to -0.09 MPa, initially heat it to 90°C, slowly add 22 g of propylene oxide to carry out polymerization reaction, and after the reaction is completed, heat it again to 100°C, slowly add 157 g of propylene oxide and continue the reaction for 0.5 h. The pressure of the reactor is maintained below 0.35 MPa. After the reaction is completed, evacuate to -0.08 MPa, bubble nitrogen for 30 min, cool to 90°C, and discharge the material to obtain a polyether polyol with high pentane miscibility.

[0038] Example 3

[0039] The preparation method of the high pentane miscible polyether polyol comprises the following steps:

[0040] (1) Add 20 g of sorbitol, 80 g of pentaerythritol and 6 g of trimethylamine into a reactor, replace with nitrogen, evacuate to -0.09 MPa, stir and heat to 110°C, slowly add 50 g of propylene oxide, keep warm and react for 3 hours, and maintain the pressure of the reactor below 0.35 MPa to obtain a polyether intermediate;

[0041] (2) Add 30 g of sucrose stearate, 30 g of sorbitan monostearate and 5 g of N,N-dimethylcyclohexylamine to the polyether intermediate. After nitrogen replacement, evacuate the reactor to -0.09 MPa, initially heat it to 85 °C, slowly add 25 g of ethylene oxide to carry out polymerization reaction, and after the reaction is completed, heat it again to 110 °C, slowly add 254 g of propylene oxide and continue the reaction for 3 h. The pressure of the reactor is maintained below 0.35 MPa. After the reaction is completed, evacuate to -0.08 MPa, bubble nitrogen for 30 min, cool to 90 °C, and discharge the material to obtain a polyether polyol with high pentane miscibility.

[0042] Comparative Example 1

[0043] The preparation method of the polyether polyol comprises the following steps:

[0044] (1) 15 g of propylene glycol, 30 g of diethylene glycol and 2 g of N,N-dimethylcyclohexylamine were added to a reactor, replaced with nitrogen, evacuated to -0.09 MPa, stirred and heated to 120°C, 44 g of butylene oxide was slowly added, and the reaction was kept warm for 0.5 h. The pressure of the reactor was maintained below 0.35 MPa to obtain a polyether intermediate;

[0045] (2) Add 200 g of palm oil and 0.5 g of N,N-dimethylcyclohexylamine to the polyether intermediate. After nitrogen replacement, evacuate the reactor to -0.09 MPa, initially heat it to 90°C, slowly add 22 g of propylene oxide to carry out polymerization reaction, and after the reaction is completed, heat it again to 100°C, slowly add 157 g of propylene oxide and continue the reaction for 0.5 h. The pressure of the reactor is maintained below 0.35 MPa. After the reaction is completed, evacuate to -0.08 MPa, bubble nitrogen for 30 min, cool to 90°C, and discharge the material to obtain polyether polyol.

[0046] Comparative Example 2

[0047] The preparation method of the polyether polyol comprises the following steps:

[0048] (1) Add 20 g of sorbitol, 80 g of pentaerythritol and 6 g of trimethylamine into a reactor, replace with nitrogen, evacuate to -0.09 MPa, stir and heat to 110°C, slowly add 50 g of propylene oxide, keep warm and react for 3 hours, and maintain the pressure of the reactor below 0.35 MPa to obtain a polyether intermediate;

[0049] (2) Add 60 g of palm oil and 5 g of N,N-dimethylcyclohexylamine to the polyether intermediate. After nitrogen replacement, evacuate the reactor to -0.09 MPa, initially heat it to 85°C, slowly add 25 g of ethylene oxide to carry out polymerization reaction, and after the reaction is completed, heat it again to 110°C, slowly add 254 g of propylene oxide and continue the reaction for 3 h. The pressure of the reactor is maintained below 0.35 MPa. After the reaction is completed, evacuate to -0.08 MPa, bubble nitrogen for 30 min, cool to 90°C, and discharge the material to obtain polyether polyol.

[0050] Comparative Example 3

[0051] The preparation method of the polyether polyol comprises the following steps:

[0052] 100 g of sorbitol, 5 g of glycerol and 10 g of dimethylamine were added to the reactor in sequence, replaced with nitrogen, evacuated to -0.09 MPa, stirred and heated to 100°C, 370 g of propylene oxide were slowly added, and the reaction was kept warm for 5 hours. The pressure of the reactor was maintained below 0.35 MPa. After the reaction was completed, the reactor was evacuated to -0.08 MPa, nitrogen was bubbled for 30 minutes, the temperature was lowered to 90°C, and the material was discharged to obtain polyether polyol.

[0053] Comparative Example 4

[0054] The preparation method of the polyether polyol comprises the following steps:

[0055] (1) Add 90 g of sucrose, 10 g of propylene glycol, 100 g of sorbitan monostearate and 10 g of dimethylamine into a reactor, replace with nitrogen, evacuate to -0.09 MPa, stir and heat to 120°C, slowly add 240 g of propylene oxide, keep warm and react for 5 h, maintain the pressure of the reactor below 0.35 MPa, evacuate to -0.08 MPa after the reaction, bubble with nitrogen for 30 min, cool to 90°C, discharge the mixture, and obtain polyether polyol.

[0056] The performance tests were performed on the polyether polyols prepared in Examples 1 to 3 and Comparative Examples 1 to 4, respectively, and the test methods were as follows:

[0057] Hydroxyl value (mgKOH / g): Tested in accordance with GB / T 12008.3-1989;

[0058] Viscosity (25°C, mPa·s): Tested in accordance with GB / T 12008.7-2010;

[0059] Fatty acid ester compound addition amount (%): the mass percentage of fatty acid ester compound (sucrose stearate, sorbitan monostearate or palm oil) in the formula components to the total amount of polyether polyols.

[0060] Cyclopentane miscibility (g / 100g polyether polyol): Cyclopentane was continuously added to 100g polyether polyol at room temperature with magnetic stirring (speed 1000rpm) until the polyether became turbid, and the mass of cyclopentane added was recorded.

[0061] Low temperature storage stability: Place the polyether polyol at -18°C for 24 hours, then return to room temperature and observe the appearance of the polyether polyol.

[0062] The test results are shown in Table 1.

[0063] Table 1 Polyether polyol performance test results

[0064]

[0065] It can be seen from the test data in Table 1 that, compared with Comparative Example 3, Examples 1 to 3 greatly improve the solubility of polyether polyols and cyclopentane through the use of polyhydroxystearate.

[0066] Under the condition of consistent addition amount of fatty acid ester compounds, the polyether polyol prepared in Comparative Example 1 will cause turbidity due to the large amount of palm oil added (42.5%), while the polyether polyol prepared in Example 2 has the appearance of a transparent liquid. This is because the large amount of hydroxyl groups contained in the polyhydroxystearate enhances its interaction with the polyether backbone, promotes its uniform dispersion in the polyether system, and effectively suppresses the turbidity of the polyether polyol.

[0067] Under the condition that the amount of fatty acid ester compound added is consistent and appropriate (12%), the appearance of the polyether polyol prepared in Comparative Example 2 is yellow and transparent at room temperature, but after low-temperature storage, oil precipitation occurs and the appearance becomes turbid, while the polyether polyol prepared in Example 3 does not precipitate oil after low-temperature storage. This is because the strong bond between polyhydroxy stearate and the main chain of polyether polyol can significantly enhance the low-temperature storage stability of polyether polyol.

[0068] Compared with the variable temperature staged polymerization process used in Example 1, the polyether polyol prepared by the one-step synthesis process in Comparative Example 4 has a low conversion rate and a high hydroxyl value. In addition, due to insufficient reaction, the obtained polyether polyol has a slightly turbid appearance after low-temperature storage.

[0069] The polyether polyols prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were formulated according to the formula shown in Table 2 to prepare composite polyethers, and the compressive strength (MPa) of the composite polyethers was tested with reference to GB / T 8813-2008. The test results are shown in Table 3.

[0070] The preparation method of the combined polyether is as follows:

[0071] Under the conditions of ambient temperature of 25°C and mold temperature of 45°C, the materials were accurately weighed according to the formula in Table 2, and prepared into a combined polyether in a 500mL beaker. 50 parts by weight of the above combined polyether and 60 parts by weight of isocyanate PM200 were fully stirred. When the system was uniform, stirring was stopped, and the stirred material was poured into a constant temperature mold. After foaming, aging and curing, it was taken out of the mold to obtain the combined polyether.

[0072] Table 2 Combination polyether formula

[0073]

[0074] in:

[0075] Polyether INOVOL R6207 was purchased from Shandong Yinuowei New Materials Co., Ltd.;

[0076] Silicone oil TEGOSTAB B8460 was purchased from Evonik Specialty Chemicals (Shanghai) Co., Ltd.

[0077] Table 3 Test results of combined polyether properties

[0078]

[0079] It can be seen from Table 3 that the compressive strength of the combined polyether prepared from the polyether polyols of Examples 1 to 3 is equivalent to the compressive strength of the combined polyether prepared from the polyether polyols of Comparative Examples 3 to 4, and is better than that of Comparative Examples 1 to 2, indicating that the high pentane miscible polyether polyols of the present invention can overcome the problem of reduced strength performance caused by the introduction of traditional vegetable oils and fats on the basis of ensuring improved pentane miscibility, thereby ensuring the strength of the combined polyether products.

Claims

1. A high pentane miscible polyether polyol, characterized in that: It is composed of the following raw materials in parts by weight: Small molecule polyol: 9~23 parts; Amine catalyst: 0.5~2.5 parts; Polyhydroxy stearate: 12-43 parts; Alkylene oxide: 47-66 parts; The small molecule polyol is one or more of sucrose, sorbitol, glycerol, diethylene glycol, propylene glycol or pentaerythritol; The polyhydroxy stearate is one or more of sucrose stearate or sorbitan monostearate; The preparation method of the high pentane miscible polyether polyol comprises the following steps: (1) adding a small molecule polyol and a first portion of an amine catalyst into a reaction kettle, replacing with nitrogen, heating, and then adding the first portion of an alkylene oxide for addition reaction to obtain a polyether intermediate; (2) Adding polyhydroxy stearate and the second part of the amine catalyst to the polyether intermediate, replacing with nitrogen, and after initial heating, adding the second stage of alkylene oxide to carry out polymerization reaction. After the reaction is completed, heating is again carried out, and the third stage of alkylene oxide is added to continue the reaction. After the reaction is completed, a high pentane miscible polyether polyol is obtained; The amount of the first-stage alkylene oxide added is 10-20 wt.% of the total amount of the alkylene oxide; the amount of the second-stage alkylene oxide added is 5-10 wt.% of the total amount of the alkylene oxide.

2. The high pentane miscible polyether polyol according to claim 1, characterized in that: The amine catalyst is one or more of dimethylamine, trimethylamine or N,N-dimethylcyclohexylamine.

3. The high pentane miscible polyether polyol according to claim 1, characterized in that: The alkylene oxide is one or more of ethylene oxide, propylene oxide or butylene oxide.

4. The high pentane miscible polyether polyol according to claim 1, characterized in that: The amount of the first part of the amine catalyst added is 50-80 wt.% of the total amount of the amine catalyst.

5. The high pentane miscible polyether polyol according to claim 1, characterized in that: In the step (1), the reaction temperature of the addition reaction is 90-120°C.

6. The high pentane miscible polyether polyol according to claim 1, characterized in that: In the step (2), the reaction temperature of the polymerization reaction after adding the second stage of alkylene oxide is 80-90°C; the reaction temperature of the continued reaction after adding the third stage of alkylene oxide is 100-120°C.

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