A process for the preparation of a reverse block polyether
By using a ring-opening polymerization method with a mixture of propylene glycol and ethylene glycol and a phosphazene catalyst, a low pour point and low foaming reverse block polyether was prepared, which solved the problems of easy solidification and insufficient foam suppression ability of reverse block polyether at low temperature, and improved the efficiency and quality of the processing fluid.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WANHUA CHEM GRP CO LTD
- Filing Date
- 2024-11-29
- Publication Date
- 2026-05-29
AI Technical Summary
Existing reverse block polyethers are prone to solidification at low temperatures and have insufficient foam suppression capabilities, which affects the efficiency and quality of the processing fluid.
A mixture of propylene glycol and ethylene glycol was used as an initiator, and ring-opening polymerization was carried out using a phosphazene catalyst. The reaction conditions of ethylene oxide and propylene oxide were controlled to ensure uniform distribution of polyoxyethylene and polyoxypropylene segments, thus preparing a low pour point and low foaming reverse block polyether.
It achieves low pour point characteristics and excellent antifoaming performance of reverse block polyether at low temperature, improving the ease of operation and antifoaming ability of the processing fluid.
Abstract
Description
Technical Field
[0001] This invention relates to the field of polyether polyols, and more particularly to a method for preparing a reverse block polyether that has both low pour point and low foaming properties. Background Technology
[0002] Conventional reverse-block polyether structures consist of polyethylene glycol segments in the middle and polypropylene glycol segments at both ends, and are widely used in metal cutting, grinding, and silicon dicing. During cutting, high-speed moving parts coming into contact with the metalworking fluid generate a large amount of foam. If the fluid's foam suppression ability is insufficient, the foam may even overflow the machining tank. Therefore, the industry has placed very high demands on the low-foaming properties of the reverse-block polyether component in the processing fluid. Furthermore, in lower temperatures such as autumn and winter, the reverse-block polyether is often already in a solid state, requiring reheating before use, which is inconvenient and affects the efficiency of customers preparing processing fluids. Therefore, the preparation of reverse-block polyethers with low pour points has always been an important research direction in the industry.
[0003] Patent CN110791363A mentions that fully synthetic cutting fluids tend to generate a large amount of foam during processing, which is difficult to dissipate. Adding silicone defoamers not only increases costs but also causes silicone precipitation during processing, affecting workpiece quality. The formulation selects reverse-block polyether components to improve lubrication and defoaming properties, achieving good results. However, the reverse-block polyethers are commercially available conventional 720 and 740. These two grades are produced by conventional KOH catalytic processes for polyethers and have a wide distribution. The end-capped propylene oxide cannot be evenly distributed at both ends of the polyether structure, resulting in some segments with fewer propylene oxide end-capped segments, thus affecting the further improvement of the polyether's foam suppression ability. Summary of the Invention
[0004] To address the above technical problems, this invention provides a method for preparing reverse block polyethers. The reverse block polyethers prepared using this method have low foaming properties and a low pour point, and are more convenient to operate at low temperatures.
[0005] To achieve the objectives of this invention, the technical solution adopted in this application is as follows:
[0006] A method for preparing a reverse block polyether includes the following steps: adding propylene glycol and ethylene glycol as initiators to a reaction vessel, using a phosphazene catalyst as a catalyst, introducing ethylene oxide to carry out ring-opening polymerization to obtain an intermediate, and then introducing propylene oxide to continue polymerization to obtain a reverse block polyether.
[0007] The initiator of the present invention is a mixture of propylene glycol and ethylene glycol, wherein the mass ratio of propylene glycol to ethylene glycol is 3 to 10:100, more preferably 5 to 8:100.
[0008] The phosphazene catalyst of the present invention is one or more of tetrakis[tris(dimethylamino)phosphonylamino]phosphine hydroxide, tetrakis[tris(dimethylamino)phosphonylamino]methoxyphosphine, tetrakis(tetramethylguanidine)phosphine hydroxide, tetrakis(tetramethylguanidine)methoxyphosphine, and trikis[tris(dimethylamino)phosphonylamino]methoxyphosphine.
[0009] The amount of phosphazene catalyst used in this invention is 10-20% of the mass of the initiator.
[0010] In this invention, the reaction temperature for the ring-opening polymerization reaction of ethylene oxide is 100-140°C, and the mass ratio of initiator to ethylene oxide is 0.5-1.5:20.
[0011] In this invention, the reaction temperature for the polymerization reaction of propylene oxide is 100-140°C, and the mass ratio of intermediate to propylene oxide is 0.4-0.8:1.
[0012] The beneficial effects of the technical solution provided by this invention are as follows:
[0013] This application uses a combination of propylene glycol and ethylene glycol as an initiator. Compared with using only ethylene glycol as an initiator, the branched structure introduced by the propylene glycol component can effectively lower the freezing point, achieving a low pour point effect without affecting foaming. Furthermore, unlike the potassium hydroxide catalyst used in conventional polyether production processes, the polyether obtained by the phosphazene catalyst selected in this invention has narrow distribution characteristics, which can better control the uniform distribution of polyoxyethylene and polyoxypropylene segments. This results in a more uniform distribution of polyoxypropylene ether segments at both ends of the polyether structure, with reasonable segment lengths, which helps suppress foam generation and ensures the overall low-foaming properties of the components. Detailed Implementation
[0014] The present invention will be further described in conjunction with the embodiments, but is not limited to the following implementation methods. Any modifications made by those skilled in the art based on the described embodiments are still within the scope of protection of this patent.
[0015] The raw materials and reagents used in this invention can all be obtained through commercial channels.
[0016] Tetra[tris(dimethylamino)phosphonylamino]phosphine hydroxide, tetra[tris(dimethylamino)phosphonylamino]methoxyphosphine, tetra(tetramethylguanidine)phosphine hydroxide, tetra(tetramethylguanidine)methoxyphosphine, tri[tris(dimethylamino)phosphonylamino]methoxyphosphine (Shanghai Aladdin Biochemical Technology Co., Ltd.)
[0017] The main testing methods are:
[0018] Polydispersity index (PDI): determined using a PL-GPC220 gel permeation chromatograph; the mobile phase was tetrahydrofuran.
[0019] Pour point: Pour point test was conducted according to national standard GB / T 3535-2006;
[0020] Maximum foam volume of dynamic foam: Using a KRUSS DFA100 dynamic foam analyzer, a 2.5 g / L aqueous solution of reverse block polyether was prepared, the temperature was controlled at 25°C, the bubbling time of the dynamic foam analyzer was set to 25 s, and the maximum foam volume generated during the entire process was recorded.
[0021] In the following embodiments, "parts" refers to parts by weight.
[0022] Example 1
[0023] First, add 3 parts of propylene glycol as an initiator, 100 parts of ethylene glycol, and 10.3 parts of tetrakis[tris(dimethylamino)phosphonium-1,4-dihydroxyamino]phosphine hydroxide catalyst to the reactor. Start stirring and heat to 100°C. Then, introduce 4120 parts of ethylene oxide and control the reaction temperature at 100°C. After the ethylene oxide feed is complete, age for 30 minutes to obtain an intermediate. Introduce 10560 parts of propylene oxide into the intermediate and control the reaction temperature at 100°C. After the propylene oxide feed is complete, age for 150 minutes to obtain a reverse-block polyether product with a PDI of 1.026, a pour point of -2.4°C, and a maximum dynamic foam volume of 103 ml.
[0024] Example 2
[0025] First, add 10 parts of propylene glycol as an initiator, 100 parts of ethylene glycol, and 22 parts of tetrakis[tris(dimethylamino)phosphonamide]methoxyphosphorus as a phosphazene catalyst to the reactor. Start stirring and heat to 140°C. Then, introduce 1467 parts of ethylene oxide and control the reaction temperature at 140°C. After the ethylene oxide feed is complete, age for 30 minutes to obtain an intermediate. Introduce 2000 parts of propylene oxide into the intermediate and control the reaction temperature at 140°C. After the propylene oxide feed is complete, age for 150 minutes to obtain a reverse-block polyether product with a PDI of 1.018, a pour point of -3.5°C, and a maximum dynamic foam volume of 95 ml.
[0026] Example 3
[0027] First, add 5 parts of propylene glycol as an initiator, 100 parts of ethylene glycol, and 16 parts of tetra(tetramethylguanidine)phosphine hydroxide catalyst to the reactor. Start stirring and heat to 120°C. Then, introduce 2100 parts of ethylene oxide and control the reaction temperature at 120°C. After the ethylene oxide feed is complete, age for 30 minutes to obtain an intermediate. Introduce 3710 parts of propylene oxide into the intermediate and control the reaction temperature at 130°C. After the propylene oxide feed is complete, age for 150 minutes to obtain a reverse-block polyether product with a PDI of 1.022, a pour point of -3.1°C, and a maximum dynamic foam volume of 101 ml.
[0028] Example 4
[0029] First, add 5 parts of propylene glycol as an initiator, 100 parts of ethylene glycol, and 12 parts of tetra(tetramethylguanidine)methoxyphosphine as a phosphazene catalyst to the reactor. Start stirring and heat to 130°C. Then, introduce 2100 parts of ethylene oxide and control the reaction temperature at 130°C. After the ethylene oxide feed is complete, age for 30 minutes to obtain an intermediate. Introduce 3710 parts of propylene oxide into the intermediate and control the reaction temperature at 130°C. After the propylene oxide feed is complete, age for 150 minutes to obtain a reverse-block polyether product with a PDI of 1.025, a pour point of -3.3°C, and a maximum dynamic foam volume of 103 ml.
[0030] Example 5
[0031] First, add 5 parts of propylene glycol as an initiator, 100 parts of ethylene glycol, and 17 parts of tris[tris(dimethylamino)phosphonamide]methoxyphosphorus as a phosphazene catalyst to the reactor. Start stirring and heat to 120°C. Then, introduce 2100 parts of ethylene oxide and control the reaction temperature at 120°C. After the ethylene oxide feed is complete, age for 30 minutes to obtain an intermediate. Introduce 3710 parts of propylene oxide into the intermediate and control the reaction temperature at 130°C. After the propylene oxide feed is complete, age for 150 minutes to obtain a reverse-block polyether product with a PDI of 1.031, a pour point of -3.7°C, and a maximum dynamic foam volume of 108 ml.
[0032] Comparative Example 1
[0033] First, add 3 parts of propylene glycol, 100 parts of ethylene glycol, and 10.3 parts of potassium hydroxide catalyst to the reactor. Start stirring and heat to 100°C. Then, introduce 4120 parts of ethylene oxide and control the reaction temperature at 100°C. After the ethylene oxide feed is complete, age for 30 minutes to obtain an intermediate. Introduce 10560 parts of propylene oxide into the intermediate and control the reaction temperature at 100°C. After the propylene oxide feed is complete, age for 150 minutes to obtain a reverse-block polyether product with a PDI of 1.053, a pour point of 4.5°C, and a maximum dynamic foam volume of 364 ml.
[0034] Comparative Example 2
[0035] First, add 100 parts of ethylene glycol as an initiator and 10.3 parts of tetrakis[tris(dimethylamino)phosphonamide]phosphine hydroxide catalyst to the reactor. Start stirring and heat to 100°C. Then, introduce 4120 parts of ethylene oxide and control the reaction temperature at 100°C. After the ethylene oxide feed is complete, age for 30 minutes to obtain an intermediate. Introduce 10560 parts of propylene oxide into the intermediate and control the reaction temperature at 100°C. After the propylene oxide feed is complete, age for 150 minutes to obtain a reverse-block polyether product with a PDI of 1.026, a pour point of 12.4°C, and a maximum dynamic foam volume of 185 ml.
[0036] The test results above show that the difference between Comparative Example 1 and Example 1 is that the catalyst was changed from a phosphazene catalyst to a conventional potassium hydroxide catalyst, and its PDI increased to 1.053. The polyoxypropylene ether segments could not be uniformly end-capped, resulting in an increase in the maximum volume of dynamic foam from 103 ml to 364 ml. At the same time, the pour point also increased due to the wider distribution, from -2.4℃ to 4.5℃. The difference between Comparative Example 2 and Example 1 is that the propylene glycol component was removed from the initiator. Due to the disappearance of the branched components, the pour point increased significantly, from -2.4℃ to 12.4℃. The foam volume also increased from 103 ml to 185 ml due to the structural changes.
[0037] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a reverse block polyether, characterized in that, The process includes the following steps: adding propylene glycol and ethylene glycol as initiators to a reactor, using phosphazene catalyst as catalyst, introducing ethylene oxide to carry out ring-opening polymerization to obtain an intermediate, and then introducing propylene oxide to continue polymerization to obtain a reverse block polyether.
2. The preparation method according to claim 1, characterized in that, The initiator is a mixture of propylene glycol and ethylene glycol, wherein the mass ratio of propylene glycol to ethylene glycol is 3 to 10:100, more preferably 5 to 8:
100.
3. The preparation method according to claim 1 or 2, characterized in that, The phosphazene catalyst is one or more of the following: tetrakis[tris(dimethylamino)phosphatidylamino]phosphine hydroxide, tetrakis[tris(dimethylamino)phosphatidylamino]methoxyphosphine, tetrakis(tetramethylguanidine)phosphine hydroxide, tetrakis(tetramethylguanidine)methoxyphosphine, and tris[tris(dimethylamino)phosphatidylamino]methoxyphosphine.
4. The preparation method according to any one of claims 1-3, characterized in that, The amount of the phosphazene catalyst used is 10-20% of the mass of the initiator.
5. The preparation method according to any one of claims 1-4, characterized in that, The reaction temperature for the ring-opening polymerization reaction of ethylene oxide is 100–140°C, and the mass ratio of initiator to ethylene oxide is 0.5–1.5:
20.
6. The preparation method according to any one of claims 1-5, characterized in that, The reaction temperature for polymerization of propylene oxide is 100–140°C, and the mass ratio of intermediate to propylene oxide is 0.4–0.8:1.