Preparation method of special initiator polyether polyol

Abstract

The invention belongs to the technical field of chemical synthesis, and specifically relates to a method for preparing a special initiator polyether polyol, wherein a special initiator is polymerized with an alkylene oxide under the action of a composite catalyst to obtain a special initiator polyether polyol; wherein the special initiator is a mixture of a conventional initiator, a small molecule polyol and an epoxy fatty acid methyl ester; wherein the conventional initiator is one or more of sucrose, sorbitol, olamine, diethylene glycol, glycerol, propylene glycol and water; and the small molecule polyol is a polyol with a saturated alkane or cycloalkane structure, which is one or more of pentaerythritol, neopentyl glycol, 1,4-cyclohexanedimethanol and tricyclodecane dimethanol. The invention obtains a polyether polyol with high hydroxyl value, low viscosity and good miscibility with pentane.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a method for preparing a special initiator polyether polyol. Background Art

[0002] Rigid foam polyether polyol is the main upstream raw material of polyurethane insulation products. It is a polyether polyol with sufficient crosslinking degree and rigidity, high functionality, high hydroxyl value and low molecular weight. Its functionality is generally 3~8, and its hydroxyl value is 300~700mgKOH / g. Rigid foam polyether polyol reacts with polyisocyanate after mixing with foaming agent and catalyst to form a foam with crosslinked network structure. The foam products formed have high hardness, high compression strength, good dimensional stability and temperature resistance. They are often used in home appliance insulation, industrial insulation, building energy conservation and other fields. At present, with the annual reduction of HCFC-141b and the high cost of other foaming agents such as 245fa and LBA, the development of other types of foaming agents and new foaming agents such as pentane system and water has been promoted. Currently, most rigid foam polyether polyols are foamed with pentane, including n-pentane, cyclopentane, isopentane, etc., but conventional polyether products are not miscible with pentane. Therefore, improving the pentane miscibility of the synthesized rigid foam polyether polyols is one of the current research technical directions. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing a special initiator polyether polyol, so as to obtain a polyether polyol with high hydroxyl value, low viscosity and good mutual solubility with pentane.

[0004] The preparation method of the special initiator polyether polyol of the present invention specifically comprises the following steps:

[0005] (1) Add special initiator and composite catalyst into the reactor in proportion, close the reactor for leak test and replace, heat to 105-115°C under nitrogen atmosphere, pressurize with nitrogen to 0.2-0.3MPa and react for 2-3h after heating;

[0006] (2) Cooling to 80-85°C, evacuating, and then dropping alkylene oxide to carry out polyether chain extension. After the feeding is completed, the internal pressure reaction is continued for 1-2 hours to obtain an intermediate polyether polyol;

[0007] (3) The intermediate polyether polyol is heated to 125-135°C, and alkylene oxide is added dropwise for end-capping synthesis. After the feeding is completed, the internal pressure reaction is continued for 2-3 hours to obtain a crude polyether polyol polymer, which is pressurized to 0.2-0.3 MPa with nitrogen filling and the pressure does not decrease any more;

[0008] (4) Cooling the crude polyether polyol to 95-105°C and bubbling with nitrogen to remove residual small molecules, cooling to 75-80°C after bubbling for 1-2 hours and discharging the material to obtain a special initiator polyether polyol.

[0009] The special initiator is a mixture of a conventional initiator, a small molecule polyol and epoxy fatty acid methyl ester;

[0010] Among them, the conventional initiator is one or more of sucrose, sorbitol, amine, diethylene glycol, glycerol, propylene glycol and water; the small molecule polyol is a polyol with a saturated alkane or cycloalkane structure, which is one or more of pentaerythritol, neopentyl glycol, 1,4-cyclohexanedimethanol and tricyclodecanedimethanol.

[0011] The epoxy value of epoxy fatty acid methyl ester is 3~3.5.

[0012] The mass percentage of epoxy fatty acid methyl ester in the special initiator is 20% to 65%.

[0013] The mass percentage of small molecule polyols in special initiators is 4%~11%.

[0014] The catalyst is one or more of triethylamine, N,N-dimethylbenzylamine, trimethylbenzylammonium chloride, chromium acetylacetonate and dimethylcyclohexylamine.

[0015] The mass of the catalyst accounts for 0.3% to 1% of the total mass of the special initiator, the catalyst and the alkylene oxide.

[0016] The alkylene oxide is one or more of ethylene oxide, propylene oxide and butylene oxide, and the percentage of alkylene oxide in the total mass of the special initiator, the catalyst and the alkylene oxide is 20% to 60%.

[0017] The mass ratio of the alkylene oxide in step (1) to the alkylene oxide in step (2) is: (4.2-0.7):1.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The epoxy fatty acid ester used in the present invention has a wide source of raw materials, is liquid at room temperature, is non-toxic and tasteless, can improve the physical properties and surface properties of the foam, and has good pentane miscibility;

[0020] 2. The present invention designs the molecular structure by using a small molecule polyol with a special alkane structure, and utilizes the difference in the active reactions of the raw materials to selectively extend the chain of alkylene oxide by controlling the synthesis process, thereby adjusting the overall molecular weight distribution and improving the mutual solubility of the polyether chain segments. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with embodiments.

[0022] Unless otherwise specified, all raw materials used in the examples and comparative examples are commercially available.

[0023] Example 1

[0024] Add 500g of epoxy fatty acid methyl ester, 150g of sucrose, 115g of diethanolamine, 20g of diethylene glycol, 40g of 1,4-cyclohexanedimethanol and 9g of triethylamine catalyst into the reactor, close the reactor and test for leakage and replace, then heat to 105-115°C under nitrogen atmosphere, after heating, pressurize with nitrogen to 0.2MPa, and react for 3h;

[0025] The temperature was lowered to 80°C, and after vacuuming to -0.09 MPa, 220 g of ethylene oxide was added dropwise to extend the polyether chain. After the feeding was completed, the internal pressure reaction was continued for 1 hour to obtain an intermediate polyether polyol.

[0026] The intermediate polyether polyol was heated to 125°C, and 147 g of propylene oxide was continuously added dropwise for end-capping synthesis. After the feeding was completed, the temperature was kept high, and the internal pressure reaction was continued for 2 h. The reactor was pressurized to 0.25 MPa with nitrogen filling, and the pressure in the reactor did not decrease any more.

[0027] After cooling to 100°C, nitrogen bubbling was performed to remove residual small molecular substances in the product. After bubbling for 1 hour, the temperature was lowered to 80°C and the polyether polyol A was discharged.

[0028] Example 2

[0029] Add 365g of epoxy fatty acid methyl ester, 180g of sucrose, 85g of diethanolamine, 20g of diethylene glycol, 40g of neopentyl glycol, 4g of N,N-dimethylbenzylamine and 5g of dimethylcyclohexylamine catalyst into the reaction kettle, close the kettle and test for leakage and replace, then heat to 105-115°C under nitrogen atmosphere, pressurize with nitrogen to 0.3MPa after heating, and react for 2h;

[0030] The temperature was lowered to 85°C, and after vacuuming to -0.09 MPa, 396 g of ethylene oxide was added dropwise to extend the polyether chain. After the feeding was completed, the internal pressure reaction was continued for 2 h to obtain an intermediate polyether polyol.

[0031] The intermediate polyether polyol was heated to 130°C, and 291 g of propylene oxide was continuously added dropwise for end-capping synthesis. After the feeding was completed, the temperature was kept high, and the internal pressure was continued for 3 hours. The pressure was increased to 0.25 MPa with nitrogen filling, and the pressure in the kettle did not decrease any more.

[0032] After cooling to 95°C, nitrogen bubbling was performed to remove residual small molecular substances in the product. After bubbling for 1 hour, the temperature was lowered to 80°C and polyether polyol B was obtained by discharging.

[0033] Example 3

[0034] Add 306g of epoxy fatty acid methyl ester, 200g of sucrose, 52.6g of diethanolamine, 46g of 1,4-cyclohexanedimethanol, 4g of trimethylbenzylammonium chloride, and 3g of chromium acetylacetone catalyst into the reaction kettle, close the kettle for leak testing and replacement, heat to 105-115°C under nitrogen atmosphere, pressurize with nitrogen to 0.2MPa after heating, and react for 2h;

[0035] The temperature was lowered to 85°C, and after vacuuming to -0.09 MPa, 228 g of ethylene oxide was added dropwise to extend the polyether chain. After the feeding was completed, the internal pressure reaction was continued for 2 h to obtain an intermediate polyether polyol.

[0036] The intermediate polyether polyol was heated to 135°C, and 58 g of propylene oxide was continuously added dropwise for end-capping synthesis. After the feeding was completed, the temperature was kept high, and the internal pressure was continued for 2 hours. The pressure was increased to 0.25 MPa with nitrogen filling, and the pressure in the kettle did not decrease any more.

[0037] After cooling to 105°C, nitrogen bubbling was performed to remove residual small molecular substances in the product. After bubbling for 2 hours, the temperature was lowered to 75°C and the polyether polyol C was obtained by discharging.

[0038] Comparative Example 1

[0039] 325 g of sucrose, 50 g of solid sorbitol, 80 g of diethylene glycol, 255 g of palm oil and 12 g of fatty amine catalyst were added to the reactor. After the reactor was closed for leak testing and replacement, the temperature was raised to 105°C under negative pressure. At the same time, the nitrogen atmosphere pressure in the reactor was maintained at 0.13 MPa. 787 g of propylene oxide was dripped into the reactor. After the dripping of propylene oxide was completed, the reaction was continued for 3 hours while keeping the temperature warm until the pressure in the reactor no longer decreased. After bubbling and stripping of monomers for 2 hours, the temperature was lowered to 80°C and the material was discharged to obtain polyether polyol B1.

[0040] Comparative Example 2

[0041] 325g of sucrose, 165g of diethylene glycol and 11.4g of DMA catalyst were added to the reactor. After the reactor was closed for leak testing and replacement, the temperature was raised to 105°C under negative pressure. At the same time, the nitrogen atmosphere pressure in the reactor was maintained at 0.13MPa. 913g of propylene oxide was dripped into the reactor. After the dripping of propylene oxide was completed, the temperature was kept warm and the reaction was continued for 3h until the pressure in the reactor no longer decreased. After bubbling and stripping of monomers for 2h, the temperature was lowered to 80°C and the material was discharged to obtain polyether polyol B2.

[0042] Performance Testing

[0043] The polyether polyols obtained in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests, and the results are shown in Table 1.

[0044] Hydroxyl value: Tested in accordance with GB / T12008.3-1989 "Determination of Hydroxyl Value in Polyether Polyols";

[0045] Viscosity: Tested in accordance with GB / T12008.7-2010 "Plastic polyether polyols Part 7: Determination of viscosity".

[0046] Table 1 Indicators of Examples 1 to 3 and Comparative Examples 1 to 2

[0047]

[0048] The polyether polyols obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were formulated according to the formula shown in Table 2, wherein PC8 is a gel catalyst, MAYCAT PC8 from Jiangsu Meside Chemical Co., Ltd.; 8815 is a uniform foaming agent, M-8815 from Jiangsu Meside Chemical Co., Ltd.;

[0049] Preparation method of polyurethane foam sample: PM200, Wanhua Chemical Group Co., Ltd. is selected as the black material, and the white material is prepared as the combined material according to Table 2. The black material and the white material are evenly mixed to obtain the polyurethane foam sample.

[0050] Table 2 Polyurethane foam formulations prepared from products of Examples 1 to 3 and Comparative Examples 1 to 2

[0051]

[0052] The obtained polyurethane foam samples were subjected to performance testing, and the results are shown in Table 3.

[0053] Strength: Tested in accordance with GB / T8813-2020 "Determination of compression properties of rigid foam plastics";

[0054] Activity: the time from the beginning of stirring the black and white materials to the beginning of hair growth and stringing;

[0055] Test method for the miscibility of n-pentane and cyclopentane: At 25°C, gradually add cyclopentane or n-pentane to 100 parts by mass of polyether polyol and mix evenly until the polyether polyol changes from clear to turbid and opaque, and record the mass fraction of pentane used at the critical point of change.

[0056] Table 3 Performance test results of polyurethane foam samples of Examples 1 to 3 and Comparative Examples 1 to 2

[0057]

[0058] It can be seen from the data in Table 3 that, compared with conventional oil-containing polyether polyols and oil-free polyether polyols, the polyurethane foam product prepared by the present invention has greater strength, higher activity, better pentane miscibility, and improved miscibility with n-pentane and cyclopentane; compared with the foam surface conditions, the surface of the product of the present invention is also significantly better than that of conventional oil-containing polyether polyols and oil-free polyether polyols.

Claims

1. A method for preparing a special initiator polyether polyol, characterized in that: A special initiator is used to polymerize with alkylene oxide under the action of a catalyst to obtain a special initiator polyether polyol; The special initiator is a mixture of a conventional initiator, a small molecule polyol and epoxy fatty acid methyl ester; Among them, the conventional initiator is one or more of sucrose, sorbitol, olamine, diethylene glycol, glycerol, propylene glycol and water; the small molecule polyol is a polyol with a saturated alkane or cycloalkane structure, which is one or more of pentaerythritol, neopentyl glycol, 1,4-cyclohexanedimethanol and tricyclodecane dimethanol; The epoxy value of epoxy fatty acid methyl ester is 3 to 3.5; The mass percentage of epoxy fatty acid methyl ester in the special initiator is 20% to 65%; The mass percentage of small molecule polyol in special initiator is 4% to 11%; The alkylene oxide is one or more of ethylene oxide, propylene oxide and butylene oxide, and the alkylene oxide accounts for 20% to 60% of the total mass of the special initiator, the catalyst and the alkylene oxide.

2. The method for preparing the special initiator polyether polyol according to claim 1, characterized in that: The catalyst is one or more of triethylamine, N,N-dimethylbenzylamine, trimethylbenzylammonium chloride, chromium acetylacetonate and dimethylcyclohexylamine.

3. The method for preparing the special initiator polyether polyol according to claim 1, characterized in that: The mass of the catalyst accounts for 0.3% to 1% of the total mass of the special initiator, the catalyst and the alkylene oxide.

4. The method for preparing the special initiator polyether polyol according to any one of claims 1 to 3, characterized in that: The specific steps include: (1) Add a special initiator and a catalyst into a reaction kettle in proportion, heat it to 105-115° C. under a nitrogen atmosphere, and pressurize it with nitrogen to 0.2-0.3 MPa after heating, and react for 2-3 hours; (2) cooling to 80-85° C., evacuating the air, and then dropping alkylene oxide to carry out polyether chain extension. After the feeding is completed, the internal pressure reaction is continued for 1-2 hours to obtain an intermediate polyether polyol; (3) heating the intermediate polyether polyol to 125-135° C., adding alkylene oxide dropwise for end-capping synthesis, and continuing the internal pressure reaction for 2-3 hours after the feeding is completed to obtain a crude polyether polyol polymer, and filling with nitrogen to pressurize to 0.2-0.3 MPa without reducing the pressure; (4) The crude polyether polyol is cooled to 95-105° C. and then nitrogen is bubbled to remove residual small molecules. After bubbling for 1-2 hours, the temperature is cooled to 75-80° C. and then discharged to obtain a special initiator polyether polyol.

5. The method for preparing the special initiator polyether polyol according to claim 4, characterized in that: The mass ratio of the alkylene oxide in step (1) to the alkylene oxide in step (2) is: (4.2-0.7):1.

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