CN115594836A - Preparation method of hard foam polyether polyol - Google Patents

Abstract

The invention belongs to the technical field of polyether polyol synthesis, and in particular relates to a rigid foam polyether polyol and a preparation method capable of effectively reducing the content of residual epoxides in the polyether polyol. For the preparation method of the rigid foam polyether polyol of the present invention, the applicant finds on the basis of the traditional amine catalyzed process that by adding water to the reaction system during the aging reaction to increase the water content of the system, the catalyst can be Effective activation can effectively improve the catalytic reaction efficiency of the product, thereby reducing the residual epoxide in the polyether product; and further consume the residual epoxide by filling the reactor with nitrogen to increase the pressure, effectively improving the reaction efficiency of the product. The preparation method of the rigid foam polyether polyol of the present invention has the advantages of simple operation, high production efficiency, energy saving and environmental protection, meets the increasingly stringent environmental protection requirements, and has good economic benefits.

Description

A kind of preparation method of hard foam polyether polyol

technical field

The invention belongs to the technical field of polyether polyol synthesis, and in particular relates to a rigid foam polyether polyol and a preparation method capable of effectively reducing the content of residual epoxides in the polyether polyol.

Background technique

Polyether polyol is referred to as polyether, also known as polyalkylene ether or polyoxyalkylene, and is usually prepared by ring-opening polymerization of epoxy compounds in the presence of active hydrogen-containing compounds as initiators and catalysts. Polyether polyol is an important raw material in the polyurethane industry, and is widely used in home appliance insulation, pipe insulation, sandwich panels, automotive interiors, coatings, etc. Among them, rigid foam polyether polyol is mostly used in the production of rigid foam External walls, refrigerator freezers, water heaters, pipes, containers and other thermal insulation fields.

In the prior art, in the rigid foam polyether polyol synthesis industry, there are usually two general production processes including the refined polyether process with KOH as a catalyst and the amine process catalyzed by dimethylamine aqueous solution. Among them, when the amine process catalyzes the synthesis of polyether added with oil, especially when the epoxide is fed to the end of the curing, the catalyst activity is greatly reduced, resulting in a high residual epoxide, which leads to the need for pumping after treatment. Vacuum removal of residual epoxy can make it below the standard, but it causes problems such as environmental pollution and seriously affects the product yield. Therefore, it is of great significance to find and solve the problem of epoxide residues caused by the synthesis of polyethers by amine technology.

For example, in the method disclosed in Chinese patent CN107903387A to increase the conversion rate of propylene oxide in the synthesis process of polyether polyols, small molecular amines are introduced in the late stage of the synthesis process of polyether polyols to consume residual PO while increasing the reactivity, thereby reducing the The purpose of PO residues in polyethers. Another example is the preparation method of rigid foam polyether polyol disclosed in Chinese patent CN106810682A, using complex amines as catalysts and adding the complex amines catalysts in stages during the reaction process to achieve high PO reaction completeness and low PO residues in the later stage of the reaction. It has the advantages of high product yield, and the air pollution of the whole process is small because the product does not need to be post-treated. Another example is the preparation method of sucrose polyether polyols disclosed in Chinese patent CN107151318A. By using liquid syrup as raw material and using novel amines as catalysts for reaction, the post-treatment process of the whole process is simple, and the addition of small molecular alcohols in oxidized olefins reaches 20 % after adding, after treatment, the removal of oxidized olefins is less, and the conversion rate of oxidized olefins is high.

Therefore, it is of positive significance to develop a synthetic method that can improve the conversion rate of epoxides in the polyether polyol synthetic process.

Contents of the invention

For this reason, the technical problem to be solved by the present invention is to provide a method for preparing rigid polyether polyols that can increase the conversion rate of epoxides in the synthesis process of polyether polyols. The advantage of simplicity;

The second technical problem to be solved by the present invention is to provide a rigid foam polyether polyol product, which has less epoxide residues and can produce finished polyether polyols without vacuum removal of epoxide residues. alcohol.

In order to solve the problems of the technologies described above, the preparation method of a kind of rigid polyether polyol of the present invention comprises the steps:

(1) Under protective atmosphere, get starter, amine catalyst, and add epoxy oxide continuously and carry out polymerization reaction;

(2) After the addition of the epoxide is completed, the aging reaction is continued, and water is added during the aging reaction for mixing, and the reaction is continued until the aging is completed.

Specifically, in the step (2), the added amount of the water accounts for 0.05%-0.2wt% of the total mass of the initiator, amine catalyst and epoxide in the reaction system.

Specifically, in the step (2), the adding time of the water is 0.5-1 h when the aging reaction is carried out.

Specifically, in the step (2), it also includes the step of continuing to introduce the protective atmosphere to increase the pressure of the reaction system after adding water;

Preferably, the protective atmosphere is introduced to control the pressure of the reaction system to 0.3-0.8 MPa. More preferably, the protective atmosphere is introduced to control the pressure of the reaction system to 0.5-0.6 MPa.

Specifically, in the step (2), the temperature of the aging reaction step is 90-125° C., and the aging reaction time is 2-6 hours.

Specifically, in the step (1), the step of continuously adding epoxides includes: raising the temperature of the reaction system to 60-70°C, adding part of the epoxides for polymerization, and then gradually raising the temperature to 90-125°C, Continuously add remaining epoxide to carry out polymerization reaction;

Preferably, the mass ratio of adding the epoxide twice is 1:15-1:30.

Specifically, in the step (1), the molar ratio of the initiator to the epoxide is 1:3.5-1:8.0;

The initiator includes polyhydric alcohol and grease;

Preferably, the mass ratio of the polyol to the oil is 1:0.08-1:1.3;

The epoxides include propylene oxide and/or ethylene oxide;

Specifically, the polyol is a compound or mixture containing two or more hydroxyl groups; preferably, the polyol includes sucrose, sorbitol, pentaerythritol, glycerin, propylene glycol, dipropylene glycol, diethylene glycol, dipropylene glycol, One or a mixture of diethylene glycol, triethylene glycol, monoethanolamine, monoethylenediisopropanolamine, diethanolamine, diethylisopropanolamine, triethanolamine, triisopropanolamine;

Preferably, the fat includes one or a mixture of vegetable oil and/or fat, animal oil and/or fat.

Specifically, in the step (1), the amine catalyst includes a mixed solution of one or more of monomethylamine, dimethylamine, trimethylamine or triethylamine;

Preferably, the added amount of the amine catalyst accounts for 0.8-1.5wt% of the total amount of the initiator, amine catalyst and epoxide in the reaction system;

Preferably, the concentration of the amine catalyst solution is 30-60wt%.

Specifically, the protective atmosphere includes nitrogen.

The invention also discloses the rigid foam polyether polyol product prepared by the method.

The preparation method of the rigid foam polyether polyol of the present invention, the applicant finds on the basis of the traditional amine catalysis process, by adding water to the reaction system during the aging reaction process to increase the water content of the system, the catalyst can be Effective activation can effectively improve the catalytic reaction efficiency of the product, thereby reducing the residual epoxide in the polyether product; and further consume the residual epoxide by filling the reactor with nitrogen to increase the pressure, effectively improving the reaction efficiency of the product. The preparation method of the rigid foam polyether polyol of the present invention, by adding water and inflating and pressurizing during the aging process, after the aging reaction is completed, the resulting product does not need to be subjected to post-processing procedures such as vacuum removal of residual epoxides. , the directly applied polyether polyol product can be obtained, which has the advantages of simple operation, high production efficiency, energy saving and environmental protection, and meets the increasingly stringent environmental protection needs, and has good economic benefits.

detailed description

Example 1

A 2L polymerization reactor was selected, 260g of sucrose, 132g of glycerin and 469g of palm oil were put into the reactor at room temperature, and enough nitrogen was introduced to replace the reactor to completely remove the oxygen in the reactor. Weigh 18g of dimethylamine aqueous solution with a mass fraction of 40wt%, and add it into the reaction kettle. The quality of the dimethylamine aqueous solution is 1.2% of the total mass of the material.

Raise the temperature of the material in the reactor to 70°C, and start to slowly and continuously drop 30g of propylene oxide for continuous polymerization reaction. During the reaction, the temperature in the reactor will gradually rise to 80-90°C; then use the heat of reaction to feed While raising the temperature to 95°C, then control the reaction temperature at 95-105°C, and continue to drop 591g of propylene oxide.

After the addition of propylene oxide is completed, keep the temperature in the kettle and carry out the aging reaction for 0.5h. At this time, add 0.75g of water (accounting for 0.05wt% of the total mass of the material) to mix, and continue to feed nitrogen to pressurize until the pressure in the kettle reaches 0.5 MPa, and continue to maintain the reaction temperature (95-105 ° C) for 3.5 hours of aging, to obtain the finished polyether polyol, the finished product is directly sampled to test the residual propylene oxide, and the detection indicators are recorded in Table 1 below.

Comparative example 1

The preparation method of the rigid foam polyether polyol described in this comparative example is the same as that of Example 1, the only difference being that the operation of adding water and feeding nitrogen to pressurize is not carried out in the described ripening step, and the described ripening step is directly at 95- Carry out at 105°C for 4 hours, and then vacuumize to remove residual propylene oxide to obtain the finished polyether polyol. Take product samples before and after vacuum treatment (i.e., samples after aging and samples after vacuuming) to detect the residual amount of propylene oxide , and the detection indicators are recorded in Table 1 below.

Example 2

Select a 2L polymerization reactor, put 322g of sucrose, 82g of glycerin and 350g of palm oil at room temperature, and feed enough nitrogen to replace the inside of the kettle to completely remove the oxygen in the kettle. Weigh 22.5 g of dimethylamine aqueous solution with a mass fraction of 30%, and add it into the reaction kettle. The mass of the dimethylamine aqueous solution is 1.5% of the total mass of the material.

Raise the temperature of the material in the reactor to 70°C, and start to slowly and continuously drop 30g of propylene oxide for continuous polymerization reaction. During the reaction, the temperature in the reactor will gradually rise to 80-90°C; then use the heat of reaction to feed While raising the temperature to 105°C, then control the reaction temperature at 105-115°C, and continue to drop 693.5g of propylene oxide.

After the propylene oxide has been added dropwise, keep the temperature in the kettle and carry out the aging reaction for 0.5h. At this time, add 1.5g of water (accounting for 0.1wt% of the total mass of the material) to mix, and continue to feed nitrogen to pressurize until the pressure in the kettle reaches 0.6 MPa, and continue to maintain the reaction temperature (105-115 ° C) for 2.5 hours of aging to obtain the finished polyether polyol. The finished product is directly sampled to test the residual propylene oxide. The test indicators are recorded in Table 1 below.

Comparative example 2

The preparation method of the rigid foam polyether polyol described in this comparative example is the same as in Example 2, the only difference being that the operation of adding water and feeding nitrogen to pressurize is not carried out in the aging step, and the aging step is directly at 105- Carry out at 115°C for 3 hours, and then vacuumize to remove residual propylene oxide to obtain the finished polyether polyol. Take product samples before and after vacuum treatment (that is, samples after aging and samples after vacuuming) to detect the residual amount of propylene oxide , and the detection indicators are recorded in Table 1 below.

Example 3

A 2L polymerization reactor was selected, and 370g of sucrose, 174g of diethylene glycol, and 194g of palm oil were put into the reactor at room temperature, and a sufficient amount of nitrogen was introduced to replace the reactor to completely remove the oxygen in the reactor. Weigh 15 g of dimethylamine aqueous solution with a mass fraction of 50%, and add it into the reaction kettle, the mass of the dimethylamine aqueous solution is 1% of the total mass of the material.

Raise the temperature of the material in the reactor to 70°C, and start to slowly and continuously drop 30g of propylene oxide for continuous polymerization reaction. During the reaction, the temperature in the reactor will gradually rise to 80-90°C; then use the heat of reaction to feed While raising the temperature to 115°C, then control the reaction temperature at 115-125°C, and continue to add 717g of propylene oxide dropwise.

After the addition of propylene oxide is completed, keep the temperature in the kettle for aging reaction for 1 hour, add 3g of water (accounting for 0.2wt% of the total mass of the material) to mix, and continue to feed nitrogen to pressurize until the pressure in the kettle reaches 0.8MPa , and continue to maintain the reaction temperature (115-125 ° C) for aging for 5 hours to obtain the finished polyether polyol. The finished product is directly sampled to test the residual propylene oxide. The detection indicators are recorded in the following table 1.

Comparative example 3

The preparation method of the rigid foam polyether polyol described in this comparative example is the same as in Example 3, the only difference being that the operation of adding water and feeding nitrogen to pressurize is not carried out in the aging step, and the aging step is directly at 115- Carry out at 125°C for 6 hours, and then vacuumize to remove residual propylene oxide to obtain the finished polyether polyol. Take product samples before and after vacuum treatment (that is, samples after aging and samples after vacuuming) to detect the residual amount of propylene oxide , and the detection indicators are recorded in Table 1 below.

Example 4

A 2L polymerization reactor was selected, 330g of sucrose, 155g of diethylene glycol and 75g of palm oil were put into the reactor at room temperature, and a sufficient amount of nitrogen was introduced to replace the reactor to completely remove the oxygen in the reactor. Weigh 12g of dimethylamine aqueous solution with a mass fraction of 60%, and add it into the reaction kettle, the mass of the dimethylamine aqueous solution is 0.8% of the total mass of the material.

Raise the temperature of the material in the reactor to 70°C, and start to slowly and continuously drop 30g of propylene oxide for continuous polymerization reaction. During the reaction, the temperature in the reactor will gradually rise to 80-90°C; then use the heat of reaction to feed While raising the temperature to 100°C, then control the reaction temperature to 100-110°C, and continue to drop 898g of propylene oxide.

After the propylene oxide is added dropwise, keep the temperature in the kettle for aging reaction for 1 hour, add 2.25g of water (accounting for 0.15% of the total mass of the material) to mix, and continue to feed nitrogen to pressurize the kettle until the pressure in the kettle reaches 0.3MPa , and continue to maintain the reaction temperature (100-110 ° C) for aging for 4 hours to obtain the finished polyether polyol. The finished product is directly sampled to test the propylene oxide residue. The detection indicators are recorded in the following table 1.

Comparative example 4

The preparation method of the rigid foam polyether polyol described in this comparative example is the same as that of Example 4, the only difference is that the operation of adding water and feeding nitrogen for pressurization is not carried out in the aging step, and the aging step is directly at 100- Carry out at 110°C for 5 hours, and then vacuumize to remove residual propylene oxide to obtain the finished polyether polyol. The product samples before and after vacuum treatment (i.e. samples after aging and samples after vacuum) were taken respectively to detect the residual amount of propylene oxide, and the detection indicators are recorded in the following table 1.

Example 5

The preparation method of the rigid polyether polyol described in this example is the same as that in Example 1, the only difference being that in the aging process, only the corresponding water addition treatment is performed, and no corresponding nitrogen pressurization operation is performed.

Example 6

The preparation method of the rigid polyether polyol described in this example is the same as that in Example 2, the only difference being that the final controlled reaction temperature is adjusted from 105-115°C to 90-100°C.

Example 7

The preparation method of the rigid polyether polyol described in this example is the same as that in Example 6, the only difference being that after adding water, continue to maintain the reaction temperature (90-100°C) for aging for 1.5h.

Example 8

The preparation method of the rigid polyether polyol described in this embodiment is the same as that in Embodiment 7, the only difference being that the amount of water added is adjusted from 0.1% to 0.05%.

Example 9

The preparation method of the rigid polyether polyol described in this example is the same as that in Example 8, the only difference being that, during the curing process, the nitrogen inflation pressure is adjusted from 0.6MPa to 0.3MPa.

Experimental example

1. Product index detection

The indexes of the polyether polyol products obtained in the above-mentioned Examples 1-9 and Comparative Examples 1-4 were tested respectively, and the test indexes included PO residue/ppm, and the test results were recorded in Table 1 below.

Table 1 embodiment 1-9 and comparative example 1-4 product detection index result

Visible, the preparation method of rigid foam polyether polyol of the present invention, on the basis of traditional amine catalyzed process, by adding water to the reaction system in the ripening reaction process to improve the mode of system water content, catalyst can be effectively deactivated. Activation can effectively improve the catalytic reaction efficiency of the product, thereby reducing the epoxide residue in the polyether product, and the obtained product does not need to be subjected to post-processing procedures such as vacuum removal of the residual epoxide, and the polyether polyol for direct application can be obtained product.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (10)

1. A preparation method of hard foam polyether polyol is characterized by comprising the following steps:

(1) Under the protective atmosphere, taking an initiator and an amine catalyst, and continuously adding epoxide for polymerization reaction;

(2) And after the epoxide is added, continuing to perform a curing reaction, adding water in the curing reaction process for mixing, and continuing to react until the curing is finished, thus obtaining the epoxide.

2. The method for preparing the hard foam polyether polyol according to claim 1, wherein in the step (2), the water is added in an amount of 0.05 to 0.2wt% based on the total mass of the initiator, the amine catalyst and the epoxide in the reaction system.

3. The method for preparing a rigid foam polyether polyol according to claim 1 or 2, wherein in the step (2), the water is added for 0.5 to 1 hour after the aging reaction.

4. The method for preparing a hard bubble polyether polyol according to any one of claims 1 to 3, wherein the step (2) further comprises the step of continuing to introduce the protective atmosphere to increase the pressure of the reaction system after adding water;

preferably, the protective atmosphere is introduced to control the pressure of the reaction system to reach 0.3-0.8MPa.

5. The process for preparing a rigid foam polyether polyol according to any one of claims 1 to 4, wherein the temperature of the aging reaction step is 90 to 125 ℃ and the aging reaction time is 2 to 6 hours.

6. A process for the preparation of a rigid foam polyether polyol according to any one of claims 1-5, wherein in step (1), the step of continuously adding an epoxide comprises: heating the reaction system to 60-70 ℃, adding part of epoxide for polymerization, gradually heating to 90-125 ℃, and continuously adding the rest epoxide for polymerization;

preferably, the mass ratio of the two times of adding the epoxide is 1:15-1:30.

7. process for the preparation of a rigid foam polyether polyol according to any one of claims 1 to 6, wherein in step (1) the molar ratio of the starter to the epoxide is from 1:3.5-1:8.0;

the initiator comprises polyhydric alcohol and grease;

preferably, the mass ratio of the polyhydric alcohol to the grease is 1:0.08-1:1.3;

the epoxide comprises propylene oxide and/or ethylene oxide;

preferably, the polyhydric alcohol comprises one or a mixture of more of sucrose, sorbitol, pentaerythritol, glycerol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, monoethanolamine, monoethylene diisopropanolamine, diethanolamine, diethylisopropanolamine, triethanolamine and triisopropanolamine;

preferably, the grease comprises one or a mixture of several of vegetable oil and/or grease, animal oil and/or grease.

8. The method for preparing a hard foam polyether polyol according to any one of claims 1 to 7, wherein in the step (1), the amine catalyst comprises a mixed solution of one or more of monomethylamine, dimethylamine, trimethylamine or triethylamine;

preferably, the adding amount of the amine catalyst accounts for 0.8-1.5wt% of the total amount of the initiator, the amine catalyst and the epoxide in the reaction system;

preferably, the concentration of the solution of the amine catalyst is 30 to 60wt%.

9. Process for the preparation of a hard bubble polyether polyol according to any one of claims 1-8, wherein the protective atmosphere comprises nitrogen.

10. A rigid foam polyether polyol product obtainable by the process of any one of claims 1 to 9.