Method for preparing low-alkalinity polyether polyols using purified hpPO process po

Abstract

The present application belongs to the technical field of polyether polyols, and particularly relates to a method for preparing low-alkalinity polyether polyols by using purified PO prepared by the HPPO method. The method comprises the following steps: (1) adding polyether waste residue to PO prepared by the HPPO method for purification treatment to obtain purified PO prepared by the HPPO method; the polyether waste residue is waste residue generated in the production of polyether polyols by a KOH catalytic process; (2) using the purified PO prepared by the HPPO method as raw material, performing polymerization reaction in the presence of a DMC catalyst and a hydroxyl-containing starter to prepare low-alkalinity polyether polyols. By using polyether waste residue generated in the production of KOH series polyether to refine PO prepared by the HPPO method, the resource utilization of the waste residue is realized, and the treatment cost is reduced; the purified PO prepared by the HPPO method obtained after the refining is used for the production of polyether polyols, which can effectively reduce the alkalinity and viscosity of the product, and solves the application pain points of PO prepared by the HPPO method.

Description

Technical Field

[0001] This invention belongs to the field of polyether polyol technology, specifically relating to a method for preparing low-alkalinity polyether polyols using the purified HPPO method for PO. Background Technology

[0002] Polyether polyols are important chemical raw materials widely used in polyurethane foams, elastomers, coatings, adhesives, and other fields. They are typically produced by ring-opening polymerization of ethylene oxide (EO) and propylene oxide (PO) with an initiator containing active hydrogen under the action of a catalyst. PO is the most widely used raw material in polyether polyol production, and its production processes mainly include the chlorohydrin process (CHPO process), the co-oxidation process (POSM process), and the hydrogen peroxide oxidation process (HPPO process). The HPPO process, due to its advantages such as mild reaction conditions, no pollutant emissions, high product selectivity, and simple process flow, has become the mainstream development direction for PO production.

[0003] However, compared with PO produced by the traditional CHPO method, PO produced by the HPPO method can lead to higher alkalinity and viscosity in the product when used for the preparation of polyether polyols. High alkalinity polyether polyols can lead to a series of adverse consequences during application: In the polyurethane foam industry, they may cause catalyst poisoning or deactivation in the foaming reaction, resulting in slower foaming speed, reduced foaming ratio, and difficulty in forming a uniform and high-quality foam structure. This, in turn, affects the foam's thermal insulation, sound insulation, and mechanical strength, and also reduces the foam's dimensional stability, making it prone to deformation during storage or use. In the adhesive industry, they can lead to decreased bonding strength and durability, while also affecting the adhesive's storage stability, causing it to deteriorate and gel during storage, shortening its shelf life and pot life. In the coating industry, they can damage coating performance, reduce coating adhesion, and easily cause peeling and flaking. They can also weaken the coating's water resistance and chemical corrosion resistance, and may react with pigments, causing discoloration or fading. In the elastomer industry, they can interfere with the crosslinking reaction, reduce the degree of crosslinking of the elastomer, affect its key properties such as elastic modulus and resilience, and accelerate elastomer aging, shortening its service life.

[0004] Therefore, reducing the alkalinity index of polyether polyols prepared by the HPPO method is of significant practical importance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing low-alkalinity polyether polyols using purified HPPO method PO. By refining the PO prepared by the HPPO method using polyether waste residue generated from KOH series polyethers, the resource utilization of the waste residue is realized, reducing processing costs. The purified HPPO method PO obtained after purification is used in the production of polyether polyols, which can effectively reduce the alkalinity and viscosity of the product, solving the application pain point of high alkalinity and viscosity of PO prepared by HPPO method when used in the production of polyether polyols.

[0006] The technical solution adopted in this invention is as follows:

[0007] The method for preparing low-alkalinity polyether polyols using the purified PO (HPPO) method includes the following steps:

[0008] (1) Add polyether waste residue to PO prepared by HPPO method for purification treatment to obtain purified HPPO method PO; the polyether waste residue is the waste residue generated in the process of producing polyether polyol by KOH catalysis;

[0009] (2) Using purified HPPO as raw material, a polymerization reaction was carried out in the presence of DMC catalyst and hydroxyl-containing initiator to obtain low-alkalinity polyether polyol.

[0010] The purification process is carried out at a temperature of 60–80°C for 0.5–1 hour.

[0011] The amount of polyether waste residue added is 1 to 3 wt. of the total amount of PO prepared by the HPPO method.

[0012] The method for preparing the polyether waste residue includes the following steps:

[0013] Using a hydroxyl-containing compound as a starting agent, it undergoes a polymerization reaction with an epoxide in the presence of a KOH catalyst. After the reaction is completed, the product is separated by acid neutralization, adsorption with an adsorbent, and filtration.

[0014] Preferably, the method for preparing the polyether waste residue includes the following steps:

[0015] S1. Add a hydroxyl-containing compound and KOH catalyst to the reaction vessel, control the temperature of the reaction system to 90-130℃, and carry out dehydration treatment under vacuum conditions for 30-90 minutes to fully remove the moisture from the raw materials.

[0016] The hydroxyl-containing compounds include, but are not limited to, one or more of n-butanol, propylene glycol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, or sorbitol;

[0017] The KOH catalyst includes, but is not limited to, an aqueous solution of KOH with a mass fraction of 30-50% or a solid KOH with a mass fraction of 85-99%.

[0018] S2. After dehydration, epoxide is added to the reactor for pre-initiation reaction. The reaction temperature is controlled at 90-110℃ and the reaction pressure is ≤0.2MPa, so that the initiator is initially activated under the action of the catalyst.

[0019] The epoxides include, but are not limited to, one or more of ethylene oxide, propylene oxide, or butane oxide;

[0020] The amount of epoxide added for the pre-initiation reaction is 10-20 wt.% of the total epoxide feed amount;

[0021] S3. After the pre-initiation reaction is completed, the remaining epoxide is continuously or in batches added to the reactor for polymerization. The reaction temperature is controlled at 100-130℃ (±5℃ fluctuation is allowed), and the reaction pressure is maintained at ≤0.5MPa. After the epoxide is added, the mixture is kept warm and stirred for a period of time to ensure that the remaining epoxide reacts completely.

[0022] S4. After the polymerization reaction is complete, a neutralizing agent is added to neutralize the alkaline catalyst in the reaction system. After neutralization, an adsorbent is added to the obtained crude polyether polyol, and adsorption purification is carried out under stirring for 30-90 minutes to remove impurities, ions and colored substances from the product.

[0023] The neutralizing agents include, but are not limited to, one or more of phosphoric acid, sulfuric acid, or organic acids;

[0024] The adsorbents mentioned include, but are not limited to, one or more of magnesium silicate, aluminum silicate, or magnesium aluminum silicate;

[0025] S5. After adsorption treatment, the reaction material is filtered. Filtration yields two parts: the filtrate is refined polyether polyol, which can be further processed to obtain the final product; the filter cake or solid residue is the polyether waste residue. This polyether waste residue contains the adsorbent, salts generated during neutralization, and various adsorbed impurities. After collection, it can be used as a purifying agent for purifying PO using the HPPO method.

[0026] Step (2) specifically includes:

[0027] A hydroxyl-containing initiator, partially purified HPPO, DMC catalyst, and acidic compound were mixed and pre-activated. The pre-activated system was then heated to dehydrate. After dehydration, induction initiation was performed, followed by the addition of the remaining purified HPPO for polymerization. After the reaction, post-treatment was performed to obtain a low-alkalinity polyether polyol.

[0028] The acidic compound is sulfuric acid, and its addition amount is 30-70 ppm containing a hydroxyl initiator.

[0029] The amount of DMC catalyst added is 50-80 ppm of the total amount of hydroxyl-containing initiator and purified HPPO PO participating in the polymerization reaction.

[0030] The amount of PO purified by the HPPO method in the pre-activation treatment is 1 to 5 wt. of the total amount of hydroxyl initiator.

[0031] The polymerization reaction is carried out at a temperature of 120–160°C.

[0032] The post-processing includes ripening and degassing.

[0033] The ripening temperature is 120–160°C, and the time is 0.5–2 hours.

[0034] The degassing time is 5 to 30 minutes.

[0035] The alkalinity of the low-alkalinity polyether polyol is ≤1 meq / 30 kg.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) The method for preparing low-alkalinity polyether polyols by purifying PO using the HPPO method described in this invention purifies the PO prepared by the HPPO method by using polyether waste generated during the production of KOH series polyether polyols. This effectively removes alkaline impurities from the PO prepared by the HPPO method, reduces the adverse effects of alkaline substances on the polymerization reaction from the source, and significantly reduces the alkalinity and viscosity of the final polyether polyol product. This ensures that the polyether polyol produced by the HPPO method is consistent with the product produced by the traditional CHPO method in terms of key indicators such as alkalinity and viscosity. This guarantees the performance of polyether polyols in various application fields such as polyurethane foam, elastomers, coatings, and adhesives, and effectively avoids problems such as abnormal foaming, decreased bonding performance, coating failure, and poor elastomer performance caused by high alkalinity. This broadens the application range of PO prepared by the HPPO method in the production of polyether polyols.

[0038] (2) The method for preparing low-alkalinity polyether polyols by purifying PO using the HPPO method described in this invention realizes the resource utilization of polyether waste residue. It not only solves the problem of waste residue treatment in the polyether production process, reduces the environmental pressure caused by waste residue accumulation, and lowers the cost of industrial solid waste treatment, but also eliminates the need for additional investment in expensive purification reagents or special equipment, simplifies the production process, reduces the preparation cost of polyether polyols, and enhances the market competitiveness of the products. Detailed Implementation

[0039] The present invention will be further described below with reference to the embodiments, but these embodiments do not limit the implementation of the present invention.

[0040] Unless otherwise specified, the raw materials used in the examples and comparative examples are all commercially available materials, and the process methods used in the examples and comparative examples are all conventional methods in the art.

[0041] The following is a description of some of the raw materials used in the examples and comparative examples:

[0042] EP-330NG and 10LD83EK (China Chemical Dongda (Zibo) Co., Ltd.) polyether waste residue.

[0043] PO prepared by the HPPO method was purchased from Lihua Yiweiyuan Chemical Co., Ltd.

[0044] PO prepared by the CHPO method was purchased from Wanhua Chemical Group Co., Ltd.

[0045] The hydroxyl-containing initiator used in the examples and comparative examples is a polyether polyol prepared by the DMC process. It is prepared by using propylene glycol as an initiator and catalyzing the polymerization reaction of propylene oxide under the action of DMC. The hydroxyl value is 56 mg KOH / g.

[0046] Example 1

[0047] The method for preparing low-alkalinity polyether polyols using the purified PO (HPPO) method includes the following steps:

[0048] (1) 0.02 kg of EP-330NG polyether waste residue was added to the purification kettle, and after nitrogen purging, the temperature was raised to 75°C. Then, 2 kg of PO prepared by HPPO method was added for purification treatment. After stirring for 0.8 h, the temperature was lowered to 15°C to obtain purified HPPO method PO.

[0049] (2) Add 400g of hydroxyl-containing initiator, 12g of purified HPPO method PO, DMC catalyst (the amount added is 80ppm of the total amount of hydroxyl-containing initiator and purified HPPO method PO (calculated as 1.602kg)) and sulfuric acid (the amount added is 70ppm of hydroxyl-containing initiator) to the reactor and stir for 1h for pre-activation treatment; raise the temperature of the pre-activated system to 95±15℃ and dehydrate under vacuum for 1h; after dehydration, continue to raise the temperature to 169℃ for induction initiation; after initiation, control the temperature of the reaction system to 140±20℃, and then add 1.602kg of purified HPPO method PO for polymerization reaction. After the reaction is completed, ripen at 140±20℃ for 1h, then degas for 10min, cool to 60℃ and filter to obtain low-alkalinity polyether polyol.

[0050] Example 2

[0051] The method for preparing low-alkalinity polyether polyols using the purified PO (HPPO) method includes the following steps:

[0052] (1) 0.04 kg of 10LD83EK polyether waste residue was added to the purification vessel, and after nitrogen purging, the temperature was raised to 70°C. Then, 2 kg of PO prepared by the HPPO method was added for purification treatment. After stirring for 1.0 h, the temperature was lowered to 15°C to obtain purified HPPO method PO.

[0053] (2) Add 400g of hydroxyl-containing initiator, 20g of purified HPPO method PO, DMC catalyst (the amount added is 50ppm of the total amount of hydroxyl-containing initiator and purified HPPO method PO (calculated as 1.602kg)) and sulfuric acid (the amount added is 30ppm of hydroxyl-containing initiator) to the reactor and stir for 1h for pre-activation treatment; raise the temperature of the pre-activated system to 95±15℃ and dehydrate under vacuum for 1h; after dehydration, continue to raise the temperature to 160℃ for induction initiation; after initiation, control the temperature of the reaction system to 140±20℃, and then add 1.602kg of purified HPPO method PO for polymerization reaction. After the reaction is completed, ripen at 140±20℃ for 1h, then degas for 10min, cool to 60℃ and filter to obtain low-alkalinity polyether polyol.

[0054] Example 3

[0055] The method for preparing low-alkalinity polyether polyols using the purified PO (HPPO) method includes the following steps:

[0056] (1) 0.04 kg of EP-330NG polyether waste residue was added to the purification kettle, and after nitrogen replacement, the temperature was raised to 80°C. Then, 2 kg of PO prepared by HPPO method was added for purification treatment. After stirring for 1.0 h, the temperature was lowered to 15°C to obtain purified HPPO method PO.

[0057] (2) Add 400g of hydroxyl-containing initiator, 12g of purified HPPO method PO, DMC catalyst (the amount added is 70ppm of the total amount of hydroxyl-containing initiator and purified HPPO method PO (calculated as 1.602kg)) and sulfuric acid (the amount added is 50ppm of hydroxyl-containing initiator) to the reactor and stir for 1h for pre-activation treatment; raise the temperature of the pre-activated system to 95±15℃ and dehydrate under vacuum for 1h; after dehydration, continue to raise the temperature to 160℃ for induction initiation; after initiation, control the temperature of the reaction system to 140±20℃, and then add 1.602kg of purified HPPO method PO for polymerization reaction. After the reaction is completed, ripen at 140±20℃ for 1h, then degas for 10min, cool to 60℃ and filter to obtain low-alkalinity polyether polyol.

[0058] Example 4

[0059] The method for preparing low-alkalinity polyether polyols using the purified PO (HPPO) method includes the following steps:

[0060] (1) 0.06 kg of EP-330NG polyether waste residue was added to the purification kettle, and after nitrogen purging, the temperature was raised to 80°C. Then, 2 kg of PO prepared by HPPO method was added for purification treatment. After stirring for 1.0 h, the temperature was lowered to 15°C to obtain purified HPPO method PO.

[0061] (2) Add 400g of hydroxyl-containing initiator, 12g of purified HPPO method PO, DMC catalyst (the amount added is 70ppm of the total amount of hydroxyl-containing initiator and purified HPPO method PO (calculated as 1.602kg)) and sulfuric acid (the amount added is 50ppm of hydroxyl-containing initiator) to the reactor and stir for 1h for pre-activation treatment; raise the temperature of the pre-activated system to 95±15℃ and dehydrate under vacuum for 1h; after dehydration, continue to raise the temperature to 160℃ for induction initiation; after initiation, control the temperature of the reaction system to 140±20℃, and then add 1.602kg of purified HPPO method PO for polymerization reaction. After the reaction is completed, ripen at 140±20℃ for 1h, then degas for 10min, cool to 60℃ and filter to obtain low-alkalinity polyether polyol.

[0062] Comparative Example 1

[0063] The method for preparing the polyether polyol includes the following steps:

[0064] 400g of hydroxyl-containing initiator, DMC catalyst (addition amount is 50ppm of the total amount of hydroxyl-containing initiator and PO prepared by CHPO method), and sulfuric acid (addition amount is 30ppm of hydroxyl-containing initiator) were added to the reactor. After stirring for 0.5h, the system was heated to 95±15℃ and vacuum dehydrated for 1h. After dehydration, the temperature was further increased to 165℃ for induction initiation. After initiation, the temperature of the reaction system was controlled at 135±15℃, and then 1.602kg of PO prepared by CHPO method was added for polymerization reaction. After the reaction was completed, it was matured at 140±20℃ for 1h, then degassed for 10min, cooled to 60℃ and discharged and filtered to obtain polyether polyol.

[0065] Comparative Example 2

[0066] The method for preparing the polyether polyol includes the following steps:

[0067] 400g of hydroxyl-containing initiator, DMC catalyst (addition amount is 50ppm of the total amount of hydroxyl-containing initiator and PO prepared by HPPO method), and sulfuric acid (addition amount is 30ppm of hydroxyl-containing initiator) were added to the reactor. After stirring for 0.5h, the system was heated to 95±15℃ and vacuum dehydrated for 1h. After dehydration, the temperature was further increased to 175℃ for induction initiation. After initiation, the reaction system temperature was controlled at 135±15℃, and then 1.602kg of PO (unpurified) prepared by HPPO method was added for polymerization reaction. After the reaction was completed, it was matured at 140±20℃ for 1h, then degassed for 10min, cooled to 60℃ and discharged and filtered to obtain polyether polyol.

[0068] Comparative Example 3

[0069] The method for preparing the polyether polyol includes the following steps:

[0070] (1) 0.04 kg of 10LD83EK polyether waste residue was added to the purification vessel, and after nitrogen purging, the temperature was raised to 70°C. Then, 2 kg of PO prepared by the HPPO method was added for purification treatment. After stirring for 1.0 h, the temperature was lowered to 15°C to obtain purified HPPO method PO.

[0071] (2) Add 400g of hydroxyl-containing initiator, 12g of purified HPPO method PO, DMC catalyst (addition amount is 50ppm of the total amount of hydroxyl-containing initiator and HPPO method PO) and sulfuric acid (addition amount is 30ppm of hydroxyl-containing initiator) to the reactor and stir for 1h for pre-activation treatment; raise the temperature of the pre-activated system to 95±15℃ and dehydrate under vacuum for 1h; after dehydration, continue to raise the temperature to 170℃ for induction initiation; after initiation, control the temperature of the reaction system to 135±15℃, and then add 1.602kg of HPPO method PO (unpurified) for polymerization reaction. After the reaction is completed, ripen at 140±20℃ for 1h, then degas for 10min, cool to 60℃ and filter to obtain polyether polyol.

[0072] The polyether polyols prepared in the examples and comparative examples were subjected to performance tests, and the test methods are as follows:

[0073] Hydroxyl value (mgKOH / g): Tested according to GB / T 12008.3-2009;

[0074] pH: Tested according to GB / T 12008.2-2010;

[0075] Acid value (mgKOH / g): Tested according to GB / T 12008.5-2010;

[0076] Alkalinity (meq / 30kg): Tested according to GB / T 12008.7-2025;

[0077] Viscosity (mPa) s): Testing shall be conducted in accordance with GB / T 12008.7-2010;

[0078] Color value (APHA): Tested according to GB / T 3143-1982.

[0079] The test results are shown in Table 1.

[0080] Table 1 Performance Test Results

[0081]

[0082] As shown in Table 1, in Examples 1-4, by using different grades of polyether waste residue to purify PO prepared by the HPPO method and adjusting parameters such as the amount of polyether waste residue added and the purification temperature, the prepared polyether polyols showed significant changes in alkalinity and viscosity. Among them, when the amount of polyether waste residue added was 2 wt.% of the total amount of PO prepared by the HPPO method, the effect of reducing the alkalinity and viscosity of the product was the best.

[0083] The test results of Comparative Example 1 and Comparative Example 2 show that, compared with the polyether polyol prepared by the CHPO method, the polyether polyol prepared by the unpurified HPPO method has significantly higher alkalinity and viscosity.

[0084] The test results of Comparative Examples 2 and 3 show that in the system of preparing polyether polyols using PO prepared by the unpurified HPPO method as raw material, the pre-activation treatment of PO prepared by the purified HPPO method before feeding can improve the alkalinity and viscosity of the product to a certain extent, but the key indicators of the product still do not meet the requirements for commercial application.

Claims

1. A method for preparing low-alkalinity polyether polyols using the HPPO purification method, characterized in that, Includes the following steps: (1) Add polyether waste residue to PO prepared by HPPO method for purification treatment to obtain purified HPPO method PO; The purification process is carried out at a temperature of 60–80°C for 0.5–1 hour. The amount of polyether waste residue added is 1-3 wt.% of the total amount of PO prepared by the HPPO method; The method for preparing the polyether waste residue includes the following steps: S1. Add a hydroxyl-containing compound and KOH catalyst to the reaction vessel, control the temperature of the reaction system to 90-130℃, and carry out dehydration treatment under vacuum conditions for 30-90 minutes to fully remove the moisture from the raw materials. The hydroxyl-containing compounds include one or more of n-butanol, propylene glycol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, or sorbitol; The KOH catalyst comprises an aqueous solution of KOH with a mass fraction of 30-50% or a solid KOH with a mass fraction of 85-99%. S2. After dehydration, epoxide is added to the reactor for pre-initiation reaction. The reaction temperature is controlled at 90-110℃ and the reaction pressure is ≤0.2MPa, so that the initiator is initially activated under the action of the catalyst. The epoxides include one or more of ethylene oxide, propylene oxide, or butane oxide; The amount of epoxide added for the pre-initiation reaction is 10-20 wt.% of the total epoxide feed amount; S3. After the pre-initiation reaction is completed, the remaining epoxide is continuously or in batches added to the reactor for polymerization. The reaction temperature is controlled at 100-130℃ and the reaction pressure is maintained at ≤0.5MPa. After the epoxide is added, the mixture is kept warm and stirred for a period of time to ensure that the remaining epoxide reacts completely. S4. After the polymerization reaction is completed, a neutralizing agent is added to neutralize the alkaline catalyst in the reaction system. After neutralization, an adsorbent is added to the obtained crude polyether polyol, and adsorption purification is carried out under stirring for 30 to 90 minutes. The neutralizing agent includes one or more of phosphoric acid, sulfuric acid, or organic acids; The adsorbent includes one or more of magnesium silicate, aluminum silicate, or magnesium aluminum silicate; S5. After the adsorption treatment is completed, the reaction material is filtered, and the filter cake or solid residue is the polyether waste residue. (2) Using purified HPPO as raw material, a polymerization reaction was carried out in the presence of DMC catalyst and hydroxyl-containing initiator to obtain low-alkalinity polyether polyol.

2. The method for preparing low-alkalinity polyether polyols using the HPPO purification method according to claim 1, characterized in that, Step (2) specifically includes: A hydroxyl-containing initiator, partially purified HPPO, DMC catalyst, and acidic compounds were mixed and pre-activated. The pre-activated system was then heated to dehydrate. After dehydration, induction initiation was performed, followed by the addition of the remaining purified HPPO for polymerization. After the reaction, post-treatment was performed to obtain a low-alkalinity polyether polyol.

3. The method for preparing low-alkalinity polyether polyols using the HPPO purification method according to claim 2, characterized in that, The acidic compound is sulfuric acid.

4. The method for preparing low-alkalinity polyether polyols using the HPPO purification method according to claim 2, characterized in that, The amount of PO purified by the HPPO method in the pre-activation treatment is 1 to 5 wt. of the total amount of hydroxyl initiator.

5. The method for preparing low-alkalinity polyether polyols using the purified HPPO method according to claim 2, characterized in that, In step (2), the polymerization reaction temperature is 120–160°C.

6. The method for preparing low-alkalinity polyether polyols using the purified HPPO method according to claim 2, characterized in that, The post-processing includes ripening and degassing.

7. The method for preparing low-alkalinity polyether polyols using the HPPO purification method according to claim 1, characterized in that, The alkalinity of the low-alkalinity polyether polyol is ≤1 meq / 30 kg.

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