Method for measuring content of trace potassium and sodium ions in allyl alcohol polyether

Abstract

The invention belongs to the technical field of polymer material analysis, and discloses a method for determining the content of trace potassium and sodium ions in allyl alcohol polyether. The determination method comprises the following steps: dissolving allyl alcohol polyether which does not contain sodium and potassium ions, isocyanate and sodium salt / potassium salt in a solvent to prepare mixed liquor with different potassium / sodium ion concentrations; heating and stirring to enable the mixed solution to form gel, recording the gelation time of each mixed solution, and establishing a corresponding relationship between the gelation time and the concentration of potassium / sodium ions in the mixed solution; the method comprises the following steps: dissolving allyl alcohol polyether to be detected and isocyanate in a solvent, then heating and stirring, and recording the gel forming time; and determining the content of potassium and sodium ions in the to-be-detected allyl alcohol polyether according to the time. The determination method provided by the invention has the advantages of low analysis cost, no need of sample pretreatment, convenience in operation, difficulty in introduction of impurities, accurate measurement result and good repeatability.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material analysis, and particularly relates to a method for determining trace potassium and sodium ion contents in allyl alcohol polyether. Background Art

[0002] Allyl alcohol polyether is a key raw material that determines the performance of polyether-modified silicone fluids. Through structural adjustments to allyl alcohol polyethers, polyether-modified silicone fluids grafted with silanol-hydrogen reactions can selectively exhibit excellent emulsification, wettability, softness, and low surface tension. They are widely used in polyurethane foam stabilizers, textile auxiliaries, oilfield demulsifiers, cosmetic additives, coating leveling agents, detergents, defoamers, and emulsifiers. However, industrially produced allyl alcohol polyethers are susceptible to various factors, including the reaction process and post-processing. Excessive residual potassium and sodium ions severely restrict the quality of allyl alcohol polyethers, posing a significant risk to the downstream polyether-modified silicone fluid industry.

[0003] Currently, the removal of potassium and sodium ion impurities from allyl alcohol polyethers is mostly achieved through neutralization-adsorption processes. For example, Chinese patent CN 108239277A describes hydrolyzing the crude polyether with water, followed by neutralization with phosphoric acid and an alkaline catalyst to form phosphates. Adsorbents and filter aids are then added, and the refined polyether product is dehydrated and filtered. Patent CN 112094404A also describes the use of cation exchange resins to purify polyether polyols, controlling the total potassium and sodium ion content to below 2 ppm.

[0004] Currently, effective analytical methods for analyzing residual potassium and sodium ion content at the parts per million (ppm) level include ion chromatography (IC) and inductively coupled plasma mass spectrometry (ICP-MS). These two methods not only require expensive, sophisticated instrumentation, but ion chromatography can damage ion exchange columns when analyzing ion content in organic matter. Meanwhile, ICP-MS typically requires complex sample pretreatment methods such as microwave digestion, which can easily introduce potassium and sodium ions from exogenous materials during the digestion process, leading to data deviations. Therefore, developing a method for determining trace potassium and sodium ion content in allyl alcohol polyethers that is simple to operate, produces accurate results, and does not require expensive, sophisticated instrumentation is of great significance for the quality control of allyl alcohol polyethers. Summary of the Invention

[0005] The present invention is intended to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a method for determining the trace potassium and sodium ion contents in allyl alcohol polyether products. The method is simple to operate, provides accurate results, and does not require expensive, precision instruments.

[0006] The invention provides a method for determining the content of trace potassium and sodium ions in allyl alcohol polyether.

[0007] Specifically, the method for determining the trace potassium and sodium ion content in allyl alcohol polyether comprises the following steps:

[0008] (1) dissolving allyl alcohol polyether, isocyanate, and sodium salt / potassium salt that do not contain sodium or potassium ions in a solvent to prepare mixed solutions containing different potassium / sodium ion concentrations; heating and stirring the mixed solutions to form gels, recording the gelation time of each mixed solution, and establishing a corresponding relationship between the gelation time and the potassium / sodium ion concentration in the mixed solution;

[0009] (2) dissolving the allyl alcohol polyether and isocyanate to be tested in a solvent to form a mixed solution to be tested; then heating and stirring the mixed solution to be tested to form a gel, and recording the time for the mixed solution to form a gel; determining the potassium and sodium ion content in the allyl alcohol polyether to be tested based on the corresponding relationship between the gel time and the potassium / sodium ion concentration in the mixed solution and the time for the mixed solution to form a gel in step (1).

[0010] It should be understood that the gel time is the time from the start of heating and stirring the mixed solution to the formation of a gel. Similarly, the gel time of the test mixed solution is the time from the start of heating and stirring the test mixed solution to the formation of a gel.

[0011] In some embodiments of the present invention, in steps (1) and (2), the temperature of the heating and stirring is 50 to 90°C; preferably, the temperature of the heating and stirring is 60 to 80°C.

[0012] In some embodiments of the present invention, in steps (1) and (2), the rotation speed of the heating and stirring is 200 to 400 r / min; preferably, the rotation speed of the heating and stirring is 250 to 350 r / min.

[0013] It should be noted that the heating and stirring conditions in steps (1) and (2) must remain consistent.

[0014] In some embodiments of the present invention, the EO ratio of the sodium-potassium ion-free allyl alcohol polyether in step (1) is 0-100%, and the structure is block or random, and the structure is end-capped or unend-capped. That is, the block or random structure is not limited, and the end-capping or end-capping form is not limited. Similarly, the EO ratio of the allyl alcohol polyether to be tested in step (2) is 0-100%, and the block or random structure is not limited, and the end-capping or end-capping form is not limited.

[0015] It should be noted that the potassium and sodium ion-free content mentioned in the present invention means that the sodium and potassium ion contents are both lower than 0.01 ppm as detected by ICP-MS.

[0016] In some embodiments of the present invention, in steps (1) and (2), the isocyanate comprises one of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), and polymethylene polyisocyanate (PM200); preferably, the isocyanate is TDI. However, it should be noted that the same isocyanate must be used in steps (1) and (2).

[0017] In some embodiments of the present invention, the solvent in step (1) includes at least one of toluene, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), ethanol, isopropanol, ethylene glycol, and propylene glycol.

[0018] In some embodiments of the present invention, the volume of the allyl alcohol polyether in step (1) accounts for 10% to 50% of the total volume of the mixed solution; the volume of the isocyanate accounts for 10% to 40% of the total volume of the mixed solution, and the volume of the solvent accounts for 20% to 50% of the total volume of the mixed solution. Preferably, the volume of the allyl alcohol polyether in step (1) accounts for 20% to 50% of the total volume of the mixed solution; the volume of the isocyanate accounts for 10% to 30% of the total volume of the mixed solution, and the volume of the solvent accounts for 30% to 50% of the total volume of the mixed solution.

[0019] In some embodiments of the present invention, the volume of the allyl alcohol polyether to be tested in step (2) accounts for 10% to 50% of the total volume of the mixed solution to be tested; the volume of the isocyanate accounts for 10% to 40% of the total volume of the mixed solution to be tested, and the volume of the solvent accounts for 20% to 50% of the total volume of the mixed solution to be tested. Preferably, in step (2), the volume of the allyl alcohol polyether to be tested accounts for 20% to 50% of the total volume of the mixed solution to be tested; the volume of the isocyanate accounts for 10% to 30% of the total volume of the mixed solution to be tested, and the volume of the solvent accounts for 30% to 50% of the total volume of the mixed solution to be tested.

[0020] In order to ensure the accuracy of the test, it is necessary to control the proportions of polyether, isocyanate and solvent in steps (1) and (2) to be consistent.

[0021] In some embodiments of the present invention, a sodium salt or potassium salt of known concentration is added to the allyl alcohol polyether to be tested. When the sodium and potassium ion contents in the allyl alcohol polyether to be tested are relatively low, the final detection accuracy can be controlled within 1 ppm by adding sodium and potassium ions and adjusting the concentrations of the added sodium and potassium ions.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention provides a determination method. Utilizing the principle that potassium and sodium ions in allyl alcohol polyether can cause isocyanate to self-polymerize and gel, and that the gelation time shortens with increasing potassium and sodium ion concentrations, a corresponding relationship between gelation time and potassium and sodium ion concentrations is established. The content of trace sodium and potassium ions in the allyl alcohol polyether sample to be measured is calculated based on the time required for the mixed liquid to gel. This method has low analytical cost, does not require sample pretreatment, is easy to operate, is not prone to the introduction of impurities, and has accurate and reproducible measurement results.

[0024] (2) The test equipment and devices required by the present invention are simple, the analysis cost is low, and it is an alternative method to high-end ICP-MS detection instruments.

[0025] (3) The results obtained by the test method of the present invention are basically consistent with the test results of ICP-MS after repeated comparative tests, and the test error is within 1 ppm. It can accurately evaluate the trace potassium and sodium ion content in allyl alcohol polyether products and effectively control the residual potassium and sodium ions in allyl alcohol polyether products and their impact on the downstream silicon-hydrogen reaction activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a diagram of the batch test experimental device in Example 1 of the present invention;

[0027] Figure 2 This is a diagram of the gel phenomenon in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0029] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0030] Example 1

[0031] 1. Instruments and Reagents

[0032] Heating stirrer model: German IKA magnetic stirrer RCT basic basic model, 100 mL beaker, 50 mL centrifuge tube;

[0033] Propylene glycol, DMF, TDI, sodium acetate, and potassium acetate were obtained with a purity of not less than 99% (Sigma-Aldrich). The HMJM series allyl alcohol polyether involved in the method was provided by Zhejiang Huangma Technology Co., Ltd.

[0034] 2. Sample Preparation

[0035] Sodium acetate standard solution A: Weigh 0.020 g of sodium acetate into a 50 mL volumetric flask, accurate to 0.0001 g, and dilute to the mark with DMF;

[0036] Potassium acetate standard solution B: Weigh 0.028 g of potassium acetate into a 50 mL volumetric flask, accurate to 0.0001 g, and dilute to the mark with DMF.

[0037] 3. Establish the corresponding relationship between gel time and potassium and sodium ion content in the polyether to be tested

[0038] The polyether product HMJM-1 (containing no potassium or sodium ions: the sodium and potassium ion contents were less than 0.01 ppm as determined by ICP-MS) produced by the DMC catalytic process was prepared with TDI, propylene glycol, DMF, and sodium acetate or potassium acetate as shown in Table 1. The solution was heated in a 70°C water bath and stirred at 300 rpm. The time was recorded from the start of heating and stirring (batch test experimental apparatus as shown in Table 1). Figure 1 When the liquid gel in the centrifuge tube (as shown) Figure 2 The end point is when the magnetic stirrer stops, and the test is stopped and the time is recorded. The difference between the two recorded times is the basis for determining the trace potassium and sodium ion content in the allyl alcohol polyether.

[0039] The experimental results shown in Table 1 show that the potassium and sodium ion content have a very significant impact on the gel time of the solution, but the difference between the two effects is not significant. When the potassium and sodium ion content in the system exceeds 10ppm of the polyether being tested, the system will gel within an hour. As the potassium and sodium ion content is gradually reduced, the corresponding gel time will also increase. When the potassium and sodium ion content of the system is controlled between 4 and 5ppm, the corresponding gel time decreases from 250min to 150min. This provides a very significant indicator difference for judging the potassium and sodium ion content in allyl alcohol polyether.

[0040] Generally speaking, after neutralization post-treatment of base-catalyzed allyl alcohol polyether, the residual potassium and sodium ions can be controlled at an extremely low level, usually within 1ppm. This method can be achieved by building in sodium ions at a concentration level of 4ppm for the polyether to be tested, which is equivalent to if there are no potassium and sodium ions remaining in the polyether to be tested. The system gelation time is about 250min. When the potassium and sodium ion content in the polyether to be tested exceeds 1ppm, the system gelation time will be within 150min. In addition, not all potassium and sodium ion content of allyl alcohol polyethers needs to be controlled within 1ppm. If it needs to be controlled within 2ppm, the proportion of built-in sodium ions to the polyether to be tested can be 3ppm. Similarly, if the potassium and sodium ion content in the polyether to be tested exceeds the standard, the gelation time will be within 150min, and so on.

[0041] Table 1 Correspondence between gel time and potassium and sodium ion content in the polyether to be tested

[0042]

[0043]

[0044] Example 2

[0045] In this example, an uncapped allyl alcohol polyoxyethylene ether HMJM-2 was selected for potassium and sodium ion content analysis. Specifically, 4.5g of the polyether to be tested, 2g of TDI, 0.6g of propylene glycol, and 5g of DMF were taken. 0.16g of sodium acetate standard solution A was added to increase the sodium ion content in the system to 4ppm of the polyether to be tested. The potassium and sodium ion content in the polyether to be tested was determined by gel time. The data are listed in Table 2. As can be seen from the data in Table 2, with 4ppm of sodium ions built in, the gel time of the system was 190 / 196 / 192min in three tests, respectively. Referring to the data in Table 1, it can be seen that the potassium and sodium ion content of the system corresponding to this gel time is between 4 and 5ppm relative to the content of the polyether to be tested. After deducting the built-in 4ppm of sodium ions, the potassium and sodium ion content of the polyether to be tested itself is between 0 and 1ppm. The potassium and sodium ion contents of the polyether HMJM-2 to be tested were also tested using the traditional ICP-MS method. The potassium ion content of the polyether to be tested was 0.05 ppm, and the sodium ion content was 0.65 ppm, which were consistent with the results measured in this example.

[0046] Example 3

[0047] In this example, an uncapped allyl alcohol polyoxyethylene polyoxypropylene ether HMJM-3 was selected for potassium and sodium ion content analysis. Specifically, 4.5g of the polyether to be tested, 2g of TDI, 0.6g of propylene glycol, and 5g of DMF were taken. 0.16g of sodium acetate standard solution A was added to make the sodium ion content in the system account for 4ppm of the polyether to be tested. The mixture was heated in a 70°C water bath and stirred at 300r / min. The potassium and sodium ion content in the polyether to be tested was determined by gel time. The data are listed in Table 2. As can be seen from the data in the table, with 4ppm of sodium ions built in, the gel time of the system was tested three times, respectively, 85 / 83 / 79min. Referring to the data in Table 1, it can be seen that the potassium and sodium ion content of the system corresponding to this gel time is between 8 and 10ppm relative to the content of the polyether to be tested. After deducting the built-in 4ppm of sodium ions, the potassium and sodium ion content of the polyether to be tested itself is between 4 and 6ppm. To further determine the potassium and sodium ion content in the polyether to be tested, the added sodium ion content was adjusted to 0 ppm. The gel time of the system was then tested three times, yielding values ​​of 212, 214, and 212 min, respectively. Referring to the data in Table 1, it can be seen that the potassium and sodium ion content within the system corresponding to these gel times was between 4 and 5 ppm relative to the content of the polyether to be tested. The potassium and sodium ion content of the polyether HMJM-3 to be tested was also tested using conventional ICP-MS. The potassium ion content of the polyether to be tested was 0.02 ppm, and the sodium ion content was 4.41 ppm, consistent with the results obtained in this example.

[0048] Example 4

[0049] In this example, a methyl-terminated allyl alcohol polyoxyethylene polyoxypropylene ether HMJM-4 was selected for potassium and sodium ion content analysis. Specifically, 4.5g of the polyether to be tested, 2g of TDI, 0.6g of propylene glycol, and 5g of DMF were taken. 0.16g of sodium acetate standard solution A was added to make the sodium ion content in the system account for 4ppm of the polyether to be tested. The mixture was heated in a 70°C water bath and stirred at 300r / min. The potassium and sodium ion content in the polyether to be tested was determined by gel time. The data are listed in Table 2. As can be seen from the data in the table, with 4ppm of sodium ions built in, the gel time of the system was tested three times, respectively, 135 / 133 / 138min. Referring to the data in Table 1, it can be seen that the potassium and sodium ion content of the system corresponding to this gel time is between 5 and 8ppm relative to the content of the polyether to be tested. After deducting the built-in 4ppm of sodium ions, the potassium and sodium ion content of the polyether to be tested itself is between 1 and 4ppm. In order to further judge the content of potassium and sodium ions in the polyether to be measured, the content of the added sodium ion was adjusted to 3ppm. At this time, the gel time of the system was tested three times and was 201 / 204 / 202min respectively. With reference to the data in Table 1, it can be seen that the potassium and sodium ion content of the internal system corresponding to this gel time is between 4 and 5ppm relative to the content of the polyether to be measured. After deducting the built-in 3ppm sodium ion, the potassium and sodium ion content of the polyether to be measured itself is between 1 and 2ppm. The potassium and sodium ion content of the polyether to be measured, HMJM-4, was also tested by traditional ICP-MS. The potassium ion content of the polyether to be measured was 0.01ppm, and the sodium ion content was 1.55ppm, which is consistent with the measured result of the present embodiment.

[0050] Example 5

[0051] In this example, an acetyl-terminated allyl alcohol polyoxyethylene polyoxypropylene ether HMJM-5 was selected for potassium and sodium ion content analysis. Specifically, 4.5g of the polyether to be tested, 2g of TDI, 0.6g of propylene glycol, and 5g of DMF were taken. 0.16g of sodium acetate standard solution A was added to increase the sodium ion content in the system to 4ppm of the polyether to be tested. The mixture was heated in a 70°C water bath and stirred at 300r / min. The potassium and sodium ion content in the polyether to be tested was determined by gel time. The data are listed in Table 2. As can be seen from the data in the table, with 4ppm of sodium ions built in, the gel time of the system was tested three times, 148 / 150 / 147min, respectively. Referring to the data in Table 1, it can be seen that the potassium and sodium ion content of the system corresponding to this gel time is close to 5ppm relative to the content of the polyether to be tested. After deducting the built-in 4ppm of sodium ions, the potassium and sodium ion content of the polyether to be tested itself is close to 1ppm. The potassium and sodium ion contents of the polyether HMJM-5 to be tested were also tested using the traditional ICP-MS method. The potassium ion content of the polyether to be tested was 0.00 ppm, and the sodium ion content was 0.94 ppm, which were consistent with the results measured in this example.

[0052] Table 2 Measurement results of Examples 2 to 5

[0053]

[0054] Example 6

[0055] To verify that the present invention is not limited to the component ratio and reaction temperature corresponding to Examples 1 to 5, the present embodiment adjusts the component ratio and reaction temperature to re-establish the corresponding relationship between gel time and potassium and sodium ion content in the polyether to be measured. Similarly, the polyether product HMJM-1 (not containing potassium and sodium ions) of the DMC catalytic process is selected to be tested with isocyanate PM200, isopropyl alcohol, DMA and sodium acetate or potassium acetate according to the solution preparation shown in Table 3, heated in a 60°C water bath, stirred at 300r / min, and the time is recorded when heated and stirred. When the liquid gels in the centrifuge tube and the magnet stops stirring, it is the end point, and the test is stopped and recorded. The difference between the two recorded times is the judgment basis for the trace potassium and sodium ion content in the allyl alcohol polyether.

[0056] Table 3 Correspondence between gel time and potassium and sodium ion content in the tested polyether

[0057]

[0058] Example 7

[0059] The present embodiment selects a methyl-terminated allyl alcohol polyoxyethylene polyoxypropylene ether HMJM-6 for potassium and sodium ion content analysis. Take 4.5g of polyether to be measured, 2.5g of pm200, 1.0g of isopropyl alcohol, and 4.1g of DMA. By adding 0.16g of sodium acetate standard solution A, the sodium ion content in the system accounts for 4ppm of the polyether to be measured, and the mixture is heated in a water bath at 60°C and stirred at 300r / min. The potassium and sodium ion content in the polyether to be measured is judged by gel time, and the data are listed in Table 4. As can be seen from the data in Table 4, when 4ppm of sodium ions are built in, the gel time of the system is tested three times and is 200 / 206 / 202min respectively. With reference to the data in Table 3, it can be seen that the potassium and sodium ion content of the corresponding system of this gel time is between 4 and 5ppm relative to the content of the polyether to be measured. After deducting the built-in 4ppm of sodium ions, the potassium and sodium ion content of the polyether to be measured itself is between 0 and 1ppm. The potassium and sodium ion contents of the polyether HMJM-5 to be tested were also tested using the traditional ICP-MS method. The potassium ion content of the polyether to be tested was 0.14 ppm, and the sodium ion content was 0.35 ppm, which were consistent with the results measured in this example.

[0060] Example 8

[0061] The present embodiment selects an acetyl-terminated allyl alcohol polyoxyethylene polyoxypropylene ether HMJM-7 for potassium and sodium ion content analysis. Take 4.5g of polyether to be tested, 2g of TDI, 0.6g of propylene glycol, and 5g of DMF. By adding 0.16g of sodium acetate standard solution A, the sodium ion content in the system accounts for 4ppm of the polyether to be tested. Heat in a 60°C water bath and stir at 300r / min. The potassium and sodium ion content in the polyether to be tested is judged by gel time. The data are listed in Table 4. As can be seen from the data in Table 4, when 4ppm of sodium ions are built in, the gel time of the system is tested three times and is 135 / 133 / 139min respectively. With reference to the data in Table 3, it can be seen that the potassium and sodium ion content of the internal system corresponding to this gel time is between 5 and 8ppm relative to the content of the polyether to be tested. After deducting the built-in 4ppm of sodium ions, the potassium and sodium ion content of the polyether to be tested itself is between 1 and 4ppm. In order to further judge the content of potassium and sodium ions in the polyether to be measured, the content of the added sodium ion is adjusted to 2ppm. At this moment, the gel time of the system is tested three times and is respectively 242 / 244 / 242min. With reference to the data in Table 3, it can be seen that the potassium and sodium ion content inside the corresponding system of this gel time is between 4 and 5ppm relative to the content of the polyether to be measured. After deducting the built-in 2ppm sodium ion, the potassium and sodium ion content of the polyether to be measured itself is between 2 and 3ppm. For this polyether to be measured HMJM-7, potassium and sodium ion content is also tested by traditional ICP-MS method. The potassium ion content of the polyether to be measured is 2.02ppm, and the sodium ion content is 0.05ppm, which is consistent with the measured result of the present embodiment.

[0062] Example 9

[0063] In this embodiment, an uncapped allyl alcohol polyoxyethylene polyoxypropylene ether HMJM-8 is selected for potassium and sodium ion content analysis. 4.5 g of the polyether to be tested, 2 g of TDI, 0.6 g of propylene glycol, and 5 g of DMF are taken. 0.16 g of sodium acetate standard solution A is added to make the sodium ion content in the system account for 4 ppm of the polyether to be tested. The system is heated in a 60 ° C water bath and stirred at 300 r / min. The potassium and sodium ion content in the polyether to be tested is judged by the gel time. The data are listed in Table 4. As can be seen from the data in Table 4, when 4 ppm of sodium ions are built in, the gel time of the system is tested three times, respectively, 218 / 220 / 217 min. With reference to the data in Table 3, it can be seen that the potassium and sodium ion content of the gel time corresponding to the system is between 4 and 5 ppm relative to the content of the polyether to be tested. After deducting the built-in 4 ppm of sodium ions, the potassium and sodium ion content of the polyether to be tested itself is between 1 and 2 ppm. The potassium and sodium ion contents of the polyether HMJM-8 to be tested were also tested using the traditional ICP-MS method. The potassium ion content of the polyether to be tested was 0.03 ppm, and the sodium ion content was 0.38 ppm, which were consistent with the results measured in this example.

[0064] Table 4 Measurement results of Examples 7 to 9

[0065]

[0066] The analysis results of the above examples show that the structural type of the polyether to be tested has little impact on the test results. The final detection accuracy can be controlled within the 1 ppm range by adjusting the concentration of the added sodium ion for different potassium and sodium ion contents. This method has a high fault tolerance rate, and a 1 ppm difference in potassium and sodium ion concentration can be amplified and read within a time span of 150 to 250 minutes.

[0067] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for determining trace potassium and sodium ion contents in allyl alcohol polyethers, characterized in that: The following steps are involved: (1) dissolving allyl alcohol polyether, isocyanate, and sodium salt / potassium salt that do not contain sodium or potassium ions in a solvent to prepare mixed solutions containing different potassium / sodium ion concentrations; heating and stirring the mixed solutions to form gels, recording the gelation time of each mixed solution, and establishing a corresponding relationship between the gelation time and the potassium / sodium ion concentration in the mixed solution; (2) dissolving the allyl alcohol polyether and isocyanate to be tested in a solvent to form a mixed solution to be tested; then heating and stirring the mixed solution to be tested to form a gel, and recording the time for the mixed solution to form a gel; determining the potassium and sodium ion content in the allyl alcohol polyether to be tested based on the corresponding relationship between the gel time and the potassium / sodium ion concentration in the mixed solution and the time for the mixed solution to form a gel in step (1).

2. The measuring method according to claim 1, wherein In steps (1) and (2), the temperature of the heating and stirring is 50 to 90°C.

3. The measuring method according to claim 2, wherein The temperature of the heating and stirring is 60-80°C.

4. The measuring method according to claim 3, wherein In steps (1) and (2), the rotation speed of the heating and stirring is 200 to 400 r / min.

5. The measuring method according to claim 1, wherein The EO ratio of the allyl alcohol polyether free of sodium and potassium ions in step (1) is 0 to 100%; the EO ratio of the allyl alcohol polyether to be tested in step (2) is 0 to 100%.

6. The measuring method according to claim 1, wherein In steps (1) and (2), the isocyanate includes one of diphenylmethane diisocyanate, toluene diisocyanate, and polymethylene polyisocyanate.

7. The measuring method according to claim 1, wherein The solvent in step (1) includes at least one of toluene, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, isopropanol, ethylene glycol, and propylene glycol.

8. The measuring method according to claim 6 or 7, characterized in that The volume of the allyl alcohol polyether in step (1) accounts for 10% to 50% of the total volume of the mixed solution; the volume of the isocyanate accounts for 10% to 40% of the total volume of the mixed solution; and the volume of the solvent accounts for 20% to 50% of the total volume of the mixed solution.

9. The measuring method according to claim 6 or 7, characterized in that In step (2), the volume of the allyl alcohol polyether to be tested accounts for 10% to 50% of the total volume of the mixed solution to be tested; the volume of the isocyanate accounts for 10% to 30% of the total volume of the mixed solution to be tested; and the volume of the solvent accounts for 20% to 50% of the total volume of the mixed solution to be tested.

10. The measuring method according to claim 1, wherein Sodium salt or potassium salt of known concentration is added to the allyl alcohol polyether to be tested.

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