Low-foam wetting agent for cutting fluid and preparation method thereof

Abstract

The invention belongs to the technical field of cutting fluids, and particularly relates to a low-foam wetting agent for a cutting fluid and a preparation method thereof. Comprising the following steps: (1) taking a cyclohexyl alcohol compound or a cyclohexyl carboxylic acid compound as an initiator, catalyzing ethylene oxide to carry out ring-opening polymerization reaction under the action of a catalyst, and curing to obtain an intermediate 1; (2) taking the intermediate 1 as an initiator, adding epoxypropane to carry out ring-opening polymerization reaction, and curing to obtain an intermediate 2; and (3) degassing the intermediate 2, and adding acid for neutralization reaction to obtain the low-foam wetting agent for the cutting fluid. An alcohol or carboxylic acid compound with relatively large steric hindrance and moderate carbon chain length and containing reactive hydrogen is selected as an initiator, and the prepared polyether is used as a wetting agent, so that the strength of a foam interface film can be effectively reduced, a foam system becomes unstable, the foam height is greatly reduced, and good wettability is shown.

Description

Technical Field

[0001] The invention belongs to the technical field of cutting fluid, and in particular relates to a low-foam wetting agent for cutting fluid and a preparation method thereof. Background Art

[0002] In the field of cutting technology, the generation of foam will bring the following effects, which are mainly reflected in the following aspects: (1) In terms of cutting quality, foam will affect the stability of the cutting fluid, which will have an adverse effect on the cutting quality. Specifically, foam will cause the cutting surface to be uneven and increase the surface roughness, thereby affecting the surface quality of the product; (2) In terms of cutting efficiency, the generation of foam will occupy the space in the cutting fluid and reduce the amount of effective cutting fluid, thereby slowing down the cutting speed and reducing the cutting efficiency; (3) In terms of equipment loss, foam accumulates inside the equipment, which will cause the equipment to run poorly, increase the maintenance cost of the equipment, prolong the downtime, and shorten the service life of the equipment. In order to reduce the generation of foam, it is usually necessary to add a large amount of defoaming agent to the cutting fluid to achieve the effect of reducing foam. However, excessive addition of defoaming agent will have an adverse effect on the appearance, lubrication and cooling performance of the cutting fluid. Therefore, in order to reduce the excessive use of defoaming agent, high requirements are placed on the selection of cutting fluid additives. In this context, low-foaming additives have received more and more attention and wide favor in related industries. 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 wetting agent for cutting fluid. By selecting alcohols or carboxylic acid compounds containing active hydrogen with large steric hindrance and moderate carbon chain length as initiators, the obtained polyether can be used as a wetting agent to effectively reduce the strength of the foam interface film, making the foam system unstable, thereby greatly reducing the foam height and showing good wetting properties.

[0004] Another object of the present invention is to provide a method for preparing a low-foaming wetting agent for cutting 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 wetting agent for cutting fluid comprises the following steps:

[0007] (1) A cyclohexyl alcohol compound or a cyclohexyl carboxylic acid compound is used as an initiator, a catalyst is added, and nitrogen is replaced three times. After vacuum dehydration, ethylene oxide is added dropwise to carry out a ring-opening polymerization reaction. After the addition is completed, aging is carried out to obtain a product having a structural formula of R-(EO) m Intermediate 1;

[0008] (2) Using intermediate 1 as an initiator, propylene oxide is added dropwise to carry out a ring-opening polymerization reaction, and after the addition is completed, the reaction is aged to obtain a product having a structural formula of R-(EO) m -(PO) n Intermediate 2;

[0009] (3) cooling to 90-100° C., degassing the intermediate 2, and further cooling to 70-80° C. after degassing, adding acid to the intermediate 2 for neutralization reaction, and filtering through a 200-500 mesh filter bag to obtain a low-foaming wetting agent for cutting fluid after neutralization;

[0010] Wherein, R in the simplified structural formula represents an initiator.

[0011] The cyclohexyl alcohol compound is one or more of cyclohexylmethanol, cyclohexylethanol or cyclohexylpropanol.

[0012] The cyclohexyl carboxylic acid compound is one or more of cyclohexylcarboxylic acid, cyclohexylacetic acid or cyclohexylpropionic acid.

[0013] The catalyst is potassium hydroxide, and the amount of the catalyst used is 0.02-1wt.% of the total amount of the initiator, ethylene oxide and propylene oxide.

[0014] The number average molecular weight of the intermediate 1 is 240-350; the number average molecular weight of the intermediate 2 is 410-580.

[0015] In the step (1), the moisture content after vacuum dehydration is ≤0.1wt.%.

[0016] In the step (1), the reaction and aging temperature is 150-170° C., and the reaction pressure is 0.01-0.05 MPa; in the step (2), the reaction and aging temperature is 130-140° C., and the reaction pressure is 0.01-0.05 MPa.

[0017] In the step (3), the degassing temperature is 90-110°C.

[0018] In the step (3), the acid is one of acetic acid, phosphoric acid, citric acid or lactic acid.

[0019] In the step (3), the pH value after the neutralization reaction is 6 to 8.

[0020] The low-foam wetting agent for cutting fluid is prepared by adopting the preparation method of the low-foam wetting agent for cutting fluid.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The low-foam wetting agent for cutting fluid of the present invention has a hydrophobic structure in the initiator with large steric hindrance and a long carbon chain. This structure makes the initiator arranged more sparsely and not tightly at the gas-liquid interface of the foam, thereby effectively reducing the strength of the interface film, so that the foam system becomes unstable and the foam height is greatly reduced. At the same time, due to the dual effects of large steric hindrance and long carbon chain, the ability of the wetting agent to form micelles in aqueous solution is reduced, the number of single molecule free states is increased, and thus it has excellent wetting properties. DETAILED DESCRIPTION

[0023] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0024] 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.

[0025] Example 1

[0026] The method for preparing the low-foam wetting agent for cutting fluid comprises the following steps:

[0027] (1) 250 g of cyclohexylethanol and 1.24 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, 231.6 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 mixture was aged at a temperature of 160±10° C. After the ageing, an intermediate 1 with a number average molecular weight of 247 was obtained.

[0028] (2) 328 g of propylene oxide was continuously added dropwise to the intermediate 1 to carry out a ring-opening polymerization reaction at a reaction pressure of 0.03±0.02 MPa. After the addition was completed, the intermediate was aged at a reaction and aging temperature of 135±5° C., and an intermediate 2 with a number average molecular weight of 415 was obtained after the aging.

[0029] (3) Cooling to 95±5°C, degassing the intermediate 2 for 15 min at a degassing temperature of 100±10°C. After degassing, the temperature is further lowered to 75±5°C, and acetic acid is added to the intermediate 2 for neutralization reaction until the pH value is 7. After neutralization, the intermediate 2 is filtered using a 200-mesh filter bag to obtain a low-foaming wetting agent for cutting fluid.

[0030] Example 2

[0031] The method for preparing the low-foam wetting agent for cutting fluid comprises the following steps:

[0032] (1) 250 g of cyclohexylpropanol and 1.22 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, 270.7 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 mixture was aged at a temperature of 160±10° C. After the ageing, an intermediate 1 with a number average molecular weight of 296 was obtained.

[0033] (2) 305.8 g of propylene oxide was continuously added dropwise to the intermediate 1 to carry out a ring-opening polymerization reaction at a reaction pressure of 0.03±0.02 MPa. After the addition was completed, the intermediate was aged at a reaction and aging temperature of 135±5° C., and an intermediate 2 with a number average molecular weight of 470 was obtained after the aging.

[0034] (3) Cooling to 95±5°C, degassing the intermediate 2 for 15 min at a degassing temperature of 100±10°C. After degassing, the temperature is further lowered to 75±5°C, and acetic acid is added to the intermediate 2 for neutralization reaction until the pH value is 6. After neutralization, the intermediate 2 is filtered using a 200-mesh filter bag to obtain a low-foaming wetting agent for cutting fluid.

[0035] Example 3

[0036] The method for preparing the low-foam wetting agent for cutting fluid comprises the following steps:

[0037] (1) 250 g of cyclohexylpropionic acid and 1.26 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, 225.3 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 1 with a number average molecular weight of 297 was obtained.

[0038] (2) 260 g of propylene oxide was continuously added dropwise to the intermediate 1 to carry out a ring-opening polymerization reaction at a reaction pressure of 0.03±0.02 MPa. After the addition was completed, the intermediate was aged at a reaction and aging temperature of 135±5° C., and an intermediate 2 with a number average molecular weight of 459 was obtained after the aging;

[0039] (3) Cooling to 95±5°C, degassing the intermediate 2 for 15 min at a degassing temperature of 100±10°C. After degassing, the temperature is further lowered to 75±5°C, and acetic acid is added to the intermediate 2 for neutralization reaction until the pH value is 7. After neutralization, the intermediate 2 is filtered using a 500-mesh filter bag to obtain a low-foaming wetting agent for cutting fluid.

[0040] Example 4

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

[0042] (1) 250 g of cyclohexyl acetic acid and 1.28 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, 208.9 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 1 with a number average molecular weight of 261 was obtained.

[0043] (2) 288 g of propylene oxide was continuously added dropwise to the intermediate 1 to carry out a ring-opening polymerization reaction at a reaction pressure of 0.03±0.02 MPa. After the addition was completed, the intermediate was aged at a reaction and aging temperature of 135±5° C., and an intermediate 2 with a number average molecular weight of 425 was obtained after the aging.

[0044] (3) Cooling to 95±5°C, degassing the intermediate 2 for 15 min at a degassing temperature of 100±10°C. After degassing, the temperature is further lowered to 75±5°C, and acetic acid is added to the intermediate 2 for neutralization reaction until the pH value is 8. After neutralization, the intermediate 2 is filtered using a 400-mesh filter bag to obtain a low-foaming wetting agent for cutting fluid.

[0045] Comparative Example 1

[0046] The preparation method of the wetting agent comprises the following steps:

[0047] (1) 250 g of dodecanol and 1.37 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 102.5±2.5° C. for 2.5 h, 295.2 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 1 with a number average molecular weight of 406 was obtained.

[0048] (2) 288 g of propylene oxide was continuously added dropwise to the intermediate 1 to carry out a ring-opening polymerization reaction at a reaction pressure of 0.03±0.02 MPa. After the addition was completed, the intermediate was aged at a reaction and aging temperature of 135±5° C., and an intermediate 2 with a number average molecular weight of 621 was obtained after the aging.

[0049] (3) Cooling to 95±5°C, degassing the intermediate 2 for 15 min at a degassing temperature of 100±10°C. After degassing, the temperature is further lowered to 75±5°C, and acetic acid is added to the intermediate 2 for neutralization reaction until the pH value is 7. After neutralization, the intermediate 2 is filtered using a 200-mesh filter bag to obtain the wetting agent.

[0050] Comparative Example 2

[0051] The method for preparing the low-foam wetting agent for cutting fluid comprises the following steps:

[0052] (1) 250 g of isomeric tridecanol and 1.31 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 102.5±2.5° C. for 2.5 h, 329.5 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 1 with a number average molecular weight of 463.6 was obtained.

[0053] (2) 289.6 g of propylene oxide was continuously added dropwise to the intermediate 1 to carry out a ring-opening polymerization reaction at a reaction pressure of 0.03±0.02 MPa. After the addition was completed, the intermediate was aged at a reaction and aging temperature of 135±5° C., and an intermediate 2 with a number average molecular weight of 695.3 was obtained after the aging;

[0054] (3) Cooling to 95±5°C, degassing the intermediate 2 for 15 min at a degassing temperature of 100±10°C. After degassing, the temperature is further lowered to 75±5°C, and acetic acid is added to the intermediate 2 for neutralization reaction until the pH value is 7. After neutralization, the intermediate 2 is filtered using a 200-mesh filter bag to obtain the wetting agent.

[0055] The wetting agents prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were subjected to performance tests, and the test method was as follows:

[0056] Foam height (mL): At room temperature, add the prepared wetting agent 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;

[0057] Wetting time (s): At room temperature, add the prepared wetting agent to deionized water to prepare 1000 mL of a 0.2 wt.% solution. Transfer the prepared solution to a beaker with a capacity of 1000 mL. Place a cut canvas piece with a diameter of 35 mm on a clean No. 420 fish hook. Then carefully move the fish hook and the canvas piece to the liquid surface of the beaker. Start a stopwatch and record the time from when the canvas piece contacts the liquid surface to when it completely sinks to the bottom of the beaker. This is the wetting time. Repeat 10 times and take the average value.

[0058] 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.

[0059] 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;

[0060] 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.

[0061] The test results are shown in Table 1:

[0062] Table 1 Performance test results

[0063] project Foam height / mL Wetting time / s HLB value Example 1 5 34.3 7.9 Example 2 12 33.1 8.3 Example 3 10 35.2 8.5 Example 4 6 36.1 8.3 Comparative Example 1 41 36.9 8.8 Comparative Example 2 36 34.5 9.1

[0064] As can be seen from Table 1, the molecular structures of the wetting agents prepared in the embodiments and comparative examples are all block structures, in which EO and PO are arranged neatly and can be adsorbed on the solid surface in a directional manner, and the hydrophilic group (-CH2-CH2-O-) is located in the middle of the molecular chain. On the one hand, due to the bending and folding of the molecular chain, these groups can be more evenly distributed in the molecules, thereby providing more interaction sites when in contact with water molecules, making it easier for water to spread and penetrate on the solid surface. On the other hand, the hydrophilic group in the middle of the molecular chain can also make the wetting agent molecules form a closer arrangement on the solid surface. This close arrangement helps to reduce the gaps and defects on the solid surface, so that the water molecules can be evenly distributed on the solid surface to form a continuous and stable water film, which can further improve the wetting effect.

[0065] In the embodiment, alcohols or carboxylic acids containing active hydrogen with large steric hindrance and medium carbon chain number are used as initiators. The prepared wetting agent has better low-foaming performance than the wetting agent synthesized by using long carbon chain alcohol as initiator in the comparative example. This is mainly because the medium carbon chain reduces the viscosity of the foam film, and at the same time, due to its large steric hindrance effect, the foaming and stability of the foam film are poor.

Claims

1. A method for preparing a low-foaming wetting agent for cutting 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 1 after aging; (2) intermediate 1 is used as an initiator, propylene oxide is added to carry out a ring-opening polymerization reaction, and intermediate 2 is obtained after aging; (3) Degassing the intermediate 2, adding acid to the intermediate 2 for neutralization after degassing, filtering after neutralization, and obtaining a low-foaming wetting agent for cutting fluid.

2. The method for preparing a low-foam wetting agent for cutting 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 the low-foam wetting agent for cutting 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 wetting agent for cutting fluid according to claim 1, characterized in that: The catalyst is potassium hydroxide, and the amount of the catalyst used is 0.02-1wt.% of the total amount of the initiator, ethylene oxide and propylene oxide.

5. The method for preparing a low-foam wetting agent for cutting fluid according to claim 1, characterized in that: The number average molecular weight of the intermediate 1 is 240-350; the number average molecular weight of the intermediate 2 is 410-580.

6. The method for preparing a low-foam wetting agent for cutting 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; in the step (2), the reaction and aging temperature is 130-140° C., and the reaction pressure is 0.01-0.05 MPa.

7. The method for preparing a low-foam wetting agent for cutting fluid according to claim 1, characterized in that: In the step (3), the degassing temperature is 90-110°C.

8. The method for preparing a low-foam wetting agent for cutting fluid according to claim 1, characterized in that: In the step (3), the acid is one of acetic acid, phosphoric acid, citric acid or lactic acid.

9. The method for preparing a low-foam wetting agent for cutting fluid according to claim 1, characterized in that: In the step (3), the pH value after the neutralization reaction is 6 to 8.

10. A low-foam wetting agent for cutting fluid, characterized in that: The cutting fluid is prepared by the method for preparing the low-foaming wetting agent for cutting fluid according to any one of claims 1 to 9.