Low-foam solubilizer for metal working fluid and preparation method of low-foam solubilizer

Abstract

The invention belongs to the technical field of metal working fluids, and particularly relates to a preparation method of a low-foam solubilizer for a metal working fluid. Comprising the following steps: (1) catalyzing ethylene oxide to perform ring-opening polymerization reaction under the action of a catalyst by taking a cyclohexyl alcohol compound or a cyclohexyl carboxylic acid compound as an initiator, and curing to prepare an intermediate of which the structural formula is R-(EO) n; and (2) degassing the intermediate, adding acid into the intermediate for neutralization reaction after degassing is finished, and filtering after neutralization is finished to obtain the low-foam solubilizer for the metal working fluid. Alcohol or carboxylic acid substances which are large in steric hindrance and medium in carbon chain number and contain reactive hydrogen are selected as initiators, and the prepared solubilizer has good low-foam performance and solubilization performance and can be arranged on a gas-liquid interface of a foam film in an evacuated and non-tight mode, so that the strength of an interface film is reduced, and the stability of the whole foam system becomes poor.

Description

Technical Field

[0001] The invention belongs to the technical field of metalworking fluids, and in particular relates to a low-foaming solubilizing agent for metalworking fluids and a preparation method thereof. Background Art

[0002] In the field of metal processing, the generation of foam will bring about several impacts. Specifically, these impacts are reflected in the following aspects: (1) In terms of metal cutting quality, foam will interfere with the stability of metalworking fluid, and then damage the cutting quality. Specific symptoms include uneven cutting surface and increased surface roughness, which will adversely affect the surface quality of the product; (2) Regarding metal cutting efficiency, the generation of foam will occupy the effective space of metalworking fluid, reduce the amount of liquid actually involved in cutting, cause the cutting speed to decrease, and affect the overall cutting efficiency; (3) As for equipment loss, if foam accumulates inside the equipment, it will hinder the smooth operation of the equipment, increase maintenance expenses, extend non-productive time, and shorten the service life of the equipment. In order to alleviate the foam problem, it is usually necessary to add a large amount of defoaming agent to the metalworking fluid to reduce the foam, but if this is excessive, it may have a negative impact on the appearance, lubricity and cooling performance of the metalworking fluid. Therefore, in order to avoid the problem of excessive use of defoaming agent, strict requirements are put forward for the selection of metalworking fluid additives. In this context, low-foaming additives have gradually become the focus of related industries and have been widely recognized and favored. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a low-foaming solubilizer for metalworking fluids. By selecting alcohols or carboxylic acids containing active hydrogen with large steric hindrance and medium carbon chain number as initiators, the prepared solubilizer has good low-foaming and solubilizing properties, and can be arranged sparsely but not tightly on the gas-liquid interface of the foam film, resulting in a reduction in the strength of the interface film and a deterioration in the stability of the overall foam system.

[0004] Another object of the present invention is to provide a method for preparing a low-foaming solubilizer for metalworking fluid, which is simple to operate and easy to industrialize.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The method for preparing the low-foam solubilizing agent for metalworking fluid comprises the following steps:

[0007] (1) Using a cyclohexyl alcohol compound or a cyclohexyl carboxylic acid compound as an initiator, catalyzing ethylene oxide to undergo a ring-opening polymerization reaction under the action of a catalyst, and preparing a product having a structural formula of R-(EO) after aging. n intermediates;

[0008] (2) cooling the intermediate to 90-100° C., degassing the intermediate, and further cooling the intermediate to 60-70° C. after degassing, adding acid to the intermediate for neutralization reaction, filtering after neutralization, and obtaining a low-foaming solubilizer for metalworking fluid;

[0009] Wherein, R in the simplified structural formula represents an initiator.

[0010] The cyclohexyl alcohol compound is one or more of cyclohexylmethanol, cyclohexylethanol or cyclohexylpropanol.

[0011] The cyclohexyl carboxylic acid compound is one or more of cyclohexylcarboxylic acid, cyclohexylacetic acid or cyclohexylpropionic acid.

[0012] In the step (1), the catalyst is potassium hydroxide, and the amount of the catalyst used is 0.02 to 1 wt.% of the total amount of the initiator and ethylene oxide.

[0013] In the step (1), the moisture content after vacuum dehydration is ≤0.1wt.%.

[0014] The number average molecular weight of the intermediate is 290-406.

[0015] In the step (1), the reaction and aging temperature is 150-170° C., and the reaction pressure is 0.01-0.05 MPa.

[0016] In the step (2), the degassing temperature is 90-100°C.

[0017] In the step (2), the acid is one of acetic acid, phosphoric acid, citric acid or lactic acid.

[0018] In the step (2), the temperature of the neutralization reaction is 60-70° C., and the pH value after the neutralization reaction is 6-8.

[0019] The low-foam solubilizer for metalworking fluid is prepared by adopting the preparation method of the low-foam solubilizer for metalworking fluid.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The low-foaming solubilizing agent for metalworking fluid of the present invention has a relatively sparse arrangement and is not tightly arranged at the gas-liquid interface of the foam due to the large hydrophobic structural steric hindrance and long carbon chain in the initiator, thereby effectively reducing the strength of the interfacial film, making the foam system unstable and greatly reducing the foam height. In addition, since the structure has both the hydrophilic and lipophilic properties of a surfactant, it exhibits good solubilizing performance. When added to a metalworking concentrate, it can significantly improve the spontaneous formation process of the emulsion. DETAILED DESCRIPTION

[0022] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0023] The raw materials used in the examples and comparative examples are conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0024] Example 1

[0025] The method for preparing the low-foam solubilizing agent for metalworking fluid comprises the following steps:

[0026] (1) 365 g of cyclohexylmethanol and 0.5 g of potassium hydroxide were added to a 2.5 L ethoxylated glass test kettle, and the atmosphere was replaced with nitrogen three times. After vacuum dehydration at 95±5° C. for 2.5 h, 635 g of ethylene oxide was added dropwise to carry out a ring-opening polymerization reaction. The reaction pressure was 0.03±0.02 MPa. After the addition was completed, the reaction was matured at a temperature of 160±10° C. After the matured reaction, an intermediate with a number average molecular weight of 312.7 was obtained.

[0027] (2) Cooling to 95±5°C, degassing the intermediate for 15 minutes at a degassing temperature of 95±5°C. After degassing, the temperature is further lowered to 65±5°C. Acetic acid is added to the intermediate for neutralization reaction until the pH value reaches 7. After neutralization, the intermediate is filtered using a 200-mesh filter bag to obtain a low-foaming solubilizer for metalworking fluids.

[0028] Example 2

[0029] The method for preparing the low-foam solubilizing agent for metalworking fluid comprises the following steps:

[0030] (1) 359 g of cyclohexylethanol and 0.75 g of potassium hydroxide were added to a 2.5 L ethoxylated glass test kettle, and the atmosphere was replaced with nitrogen three times. After vacuum dehydration at 95±5° C. for 3 h, 641 g of ethylene oxide was added dropwise to carry out a ring-opening polymerization reaction. The reaction pressure was 0.03±0.02 MPa. After the addition was completed, the reaction was carried out and the reaction and aging temperature was 160±10° C. After aging, an intermediate with a number average molecular weight of 357.1 was obtained;

[0031] (2) Cooling to 95±5°C, degassing the intermediate for 15 minutes at a degassing temperature of 95±5°C. After degassing, the temperature is further lowered to 65±5°C, and acetic acid is added to the intermediate for neutralization reaction until the pH value is 8. After neutralization, the intermediate is filtered using a 500-mesh filter bag to obtain a low-foaming solubilizer for metalworking fluids.

[0032] Example 3

[0033] The method for preparing the low-foam solubilizing agent for metalworking fluid comprises the following steps:

[0034] (1) 350 g of cyclohexylpropanol and 0.5 g of potassium hydroxide were added to a 2.5 L ethoxylated glass test kettle, and the atmosphere was replaced with nitrogen three times. After vacuum dehydration at 95±5° C. for 2 h, 650 g of ethylene oxide was added dropwise to carry out a ring-opening polymerization reaction. The reaction pressure was 0.03±0.02 MPa. After the addition was completed, the reaction was aging. The reaction and aging temperature was 160±10° C. After aging, an intermediate with a number average molecular weight of 406 was obtained.

[0035] (2) Cooling to 95±5°C, degassing the intermediate for 15 minutes at a degassing temperature of 95±5°C. After degassing, the temperature is further lowered to 65±5°C, and acetic acid is added to the intermediate for neutralization reaction until the pH value is 6. After neutralization, the intermediate is filtered using a 400-mesh filter bag to obtain a low-foaming solubilizer for metalworking fluids.

[0036] Example 4

[0037] The method for preparing the low-foam solubilizing agent for metalworking fluid comprises the following steps:

[0038] (1) 409.4 g of cyclohexanecarboxylic acid and 1 g of potassium hydroxide were added to a 2.5 L ethoxylated glass test kettle, and the atmosphere was replaced with nitrogen three times. After vacuum dehydration at 95±5° C. for 2.5 h, 590.6 g of ethylene oxide was added dropwise to carry out a ring-opening polymerization reaction. The reaction pressure was 0.03±0.02 MPa. After the addition was completed, the reaction was matured at a temperature of 160±10° C. After the matured reaction, an intermediate with a number average molecular weight of 313 was obtained.

[0039] (2) Cooling to 95±5°C, degassing the intermediate for 15 minutes at a degassing temperature of 95±5°C. After degassing, the temperature is further lowered to 65±5°C, and acetic acid is added to the intermediate for neutralization reaction until the pH value is 8. After neutralization, the intermediate is filtered using a 400-mesh filter bag to obtain a low-foaming solubilizer for metalworking fluids.

[0040] Example 5

[0041] The method for preparing the low-foam solubilizing agent for metalworking fluid comprises the following steps:

[0042] (1) 392.6 g of cyclohexyl acetic acid and 1 g of potassium hydroxide were added to a 2.5 L ethoxylated glass test kettle, and the atmosphere was replaced with nitrogen three times. After vacuum dehydration at 95±5° C. for 3 h, 607.4 g of ethylene oxide was added dropwise to carry out a ring-opening polymerization reaction. The reaction pressure was 0.03±0.02 MPa. After the addition was completed, the reaction was matured at a temperature of 160±10° C. After the matured reaction, an intermediate with a number average molecular weight of 362 was obtained.

[0043] (2) Cooling to 95±5°C, degassing the intermediate for 15 minutes at a degassing temperature of 95±5°C. After degassing, the temperature is further lowered to 65±5°C, and acetic acid is added to the intermediate for neutralization reaction until the pH value reaches 7. After neutralization, the intermediate is filtered using a 400-mesh filter bag to obtain a low-foaming solubilizer for metalworking fluids.

[0044] Comparative Example 1

[0045] The preparation method of the solubilizing agent comprises the following steps:

[0046] (1) 376.5 g of dodecanol and 0.5 g of potassium hydroxide were added to a 2.5 L ethoxylated glass test kettle, and the atmosphere was replaced with nitrogen three times. After vacuum dehydration at 105±5° C. for 3 h, 623.5 g of ethylene oxide was added dropwise to carry out a ring-opening polymerization reaction at a pressure of 0.03±0.02 MPa. After the addition was completed, the reaction was allowed to mature at a temperature of 160±10° C. After the aging, an intermediate with a number average molecular weight of 495 was obtained.

[0047] (2) Cooling the mixture to 95±5°C and degassing the intermediate for 15 min at a degassing temperature of 95±5°C. After degassing, the mixture is further cooled to 65±5°C. Acetic acid is added to the intermediate for neutralization until the pH value reaches 7. After neutralization, the mixture is filtered using a 400-mesh filter bag to obtain a solubilizing agent.

[0048] Comparative Example 2

[0049] The preparation method of the solubilizing agent comprises the following steps:

[0050] (1) 363 g of isomeric tridecanol and 0.5 g of potassium hydroxide were added to a 2.5 L ethoxylated glass test kettle, and the atmosphere was replaced with nitrogen three times. After vacuum dehydration at 105±5° C. for 3 h, 637 g of ethylene oxide was added dropwise to carry out a ring-opening polymerization reaction. The reaction pressure was 0.03±0.02 MPa. After the addition was completed, the reaction was matured at a temperature of 160±10° C. After the matured reaction, an intermediate with a number average molecular weight of 551 was obtained.

[0051] (2) Cooling the mixture to 95±5°C and degassing the intermediate for 15 min at a degassing temperature of 95±5°C. After degassing, the mixture is further cooled to 65±5°C. Acetic acid is added to the intermediate for neutralization until the pH value reaches 7. After neutralization, the mixture is filtered using a 400-mesh filter bag to obtain a solubilizing agent.

[0052] The solubilizers prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were subjected to performance tests, and the test method was as follows:

[0053] Foam height (mL): At room temperature, add the prepared solubilizer to deionized water to prepare a 0.2wt.% solution, transfer 20mL of the solution into a 100mL stoppered measuring cylinder, seal it and shake it up and down vigorously 10 times, and record the foam height, foam height = foam height - initial height;

[0054] Defoaming time (s): Add the prepared solubilizer to deionized water to prepare a 0.2wt.% solution, transfer 20mL of the solution into a 100mL stoppered measuring cylinder, seal it, shake it up and down vigorously 10 times, and then start timing the time it takes for the foam to disappear;

[0055] HLB value: Use the water number method to establish a standard curve for the 1,4-dioxane / benzene system. Weigh 1 g of a mixture of Span 80 and Tween 80 in different mass ratios in a 100 mL conical flask, add 30 mL of a mixed solution of 1,4-dioxane / benzene (volume ratio of 96:4), control the temperature at around 30°C, put a piece of white paper with No. 3 font on the bottom of the conical flask, use a burette to titrate while shaking the conical flask and keep a constant temperature during the titration process. The titration endpoint is when the No. 3 font becomes blurred. Record the volume of distilled water consumed, which is the water number, calculate the HLB value of the mixture, and draw a standard curve with the water number against the HLB value.

[0056] The calculation formula of HLB value is: 混 =∑(HLB i ×q i ); HLB i is the HLB value of a certain surfactant in the mixed system, q i is the mass fraction of the surfactant in the mixed system;

[0057] Dissolve 1 g of the sample in 30 mL of a mixed solvent of 1,4-dioxane / benzene (volume ratio 96:4), titrate with distilled water until the solution becomes stable and turbid (the turbidity does not disappear within 1 min), and record the mL of water added.

[0058] The test results are shown in Table 1:

[0059] Table 1 Performance test results

[0060] project Foam height / mL Defoaming time / s HLB value Example 1 12 15 12.7 Example 2 18 24 12.8 Example 3 23 33 13 Example 4 11 13 13.2 Example 5 18 20 13.5 Comparative Example 1 49 ＞200 12.5 Comparative Example 2 42 ＞200 12.7

[0061] As can be seen from Table 1, the polyether structures synthesized in the embodiments and comparative examples are all R-(EO) n, one end of the structure is a hydrophilic chain end, and the other end is a hydrophobic chain segment, which is suitable for use as a solubilizing agent. The structure can spontaneously form micelles in water, the micelle core is a non-polar carbon chain, the micelle outer layer is a polar substance, and the insoluble matter is a non-polar substance. Due to the hydrophobic effect, the insoluble matter can be wrapped in the micelle core, thereby playing a solubilizing role. In the embodiment, the solubilizing agent prepared by using alcohols or carboxylic acids containing active hydrogen with large steric hindrance and medium carbon chain number as initiators has better low-foaming performance than the solubilizing agent prepared by using long carbon chains in the comparative example, and the defoaming speed is fast, which is suitable for the field of metalworking fluids.

Claims

1. A method for preparing a low-foam solubilizing agent for metalworking fluid, characterized in that: The following steps are involved: (1) using a cyclohexyl alcohol compound or a cyclohexyl carboxylic acid compound as an initiator, catalyzing ethylene oxide to undergo a ring-opening polymerization reaction under the action of a catalyst, and preparing an intermediate after aging; (2) Degassing the intermediate, adding acid to the intermediate for neutralization after degassing, filtering after neutralization, and obtaining a low-foaming solubilizer for metalworking fluid.

2. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: The cyclohexyl alcohol compound is one or more of cyclohexylmethanol, cyclohexylethanol or cyclohexylpropanol.

3. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: The cyclohexyl carboxylic acid compound is one or more of cyclohexylcarboxylic acid, cyclohexylacetic acid or cyclohexylpropionic acid.

4. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: In the step (1), the catalyst is potassium hydroxide, and the amount of the catalyst used is 0.02 to 1 wt.% of the total amount of the initiator and ethylene oxide.

5. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: The number average molecular weight of the intermediate is 290-406.

6. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: In the step (1), the reaction and aging temperature is 150-170° C., and the reaction pressure is 0.01-0.05 MPa.

7. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: In the step (2), the degassing temperature is 90-100°C.

8. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: In the step (2), the acid is one of acetic acid, phosphoric acid, citric acid or lactic acid.

9. The method for preparing a low-foam solubilizing agent for metalworking fluid according to claim 1, characterized in that: In the step (2), the temperature of the neutralization reaction is 60-70° C., and the pH value after the neutralization reaction is 6-8.

10. A low-foam solubilizing agent for metalworking fluid, characterized in that: The low-foam solubilizing agent for metalworking fluid is prepared by the preparation method of any one of claims 1 to 9.