Modified dispersing agent, preparation method thereof, cutting fluid containing modified dispersing agent and application of cutting fluid

Abstract

The invention belongs to the technical field of silicon wafer cutting, and particularly relates to a modified dispersing agent, a preparation method thereof, cutting fluid containing the modified dispersing agent and application of the cutting fluid. The structural formula of the modified dispersant provided by the invention is as shown in formula 1. The cutting fluid provided by the invention comprises the modified dispersant, a lubricant, a pH regulator and water. The cutting fluid is stable in performance, easy to store, environmentally friendly, not prone to blistering in actual use, low in viscosity and excellent in use effect. # imgabs0 #

Description

Technical Field

[0001] The present application relates to the technical field of silicon material cutting, and in particular to a modified dispersant, a preparation method thereof, a cutting fluid containing the same, and an application of the cutting fluid. Background Art

[0002] As an auxiliary consumable product that must be used in the cutting process of semiconductor silicon materials, the use requirements of cutting fluid have continuously emerged with more excellent performance requirements with the development of the optical industry.

[0003] Currently, there are generally some problems in the silicon wafer cutting fluids widely used in the market. For example, the formulations mostly use water as the main solvent, and a large amount of water-soluble surfactants and other functional additives such as antioxidants, defoamers, thickeners and other functional components must be added. Although the cutting fluid containing multi-functional components obtained in this way can increase the overall dispersion performance of the system, it also results in serious foaming and high COD in the overall cutting fluid, and the viscosity will also increase during cutting use, increasing the power consumption of cutting equipment and increasing the cost of cutting processes.

[0004] Therefore, it is of great significance to research and develop a cutting fluid that is not easy to foam and has a low viscosity when mixing mortar, and at the same time meets excellent application performance. Summary of the Invention

[0005] The purpose of the present application is to provide a modified dispersant. When the modified dispersant is used to prepare a cutting fluid, an environmentally friendly cutting fluid that is not easy to foam, has a low viscosity, and still has excellent use effects can be obtained.

[0006] In the first aspect of the present application, a modified dispersant is provided, and its structural formula is shown in Formula 1:

[0007]

[0008] Wherein, each R1 is the same or different, and each independently selected from a straight-chain alkyl group having 19 to 29 carbon atoms.

[0009] In the second aspect of the present application, a preparation method of the modified dispersant according to the first aspect is provided, including the following steps:

[0010] Perform a hydroxyl activation reaction on 2,5-dimethyl-2,5-hexanediol to obtain a hydroxyl-activated alcohol reactant; perform an esterification reaction on the straight-chain alkyl carboxylic acid R1-COOH and the obtained hydroxyl-activated alcohol reactant to obtain a modified dispersant as shown in Formula 1;

[0011] Wherein, R1 has the same definition as in the first aspect of the present application.

[0012] In the third aspect of the present application, a cutting fluid is provided, which comprises the modified dispersant, lubricant, pH regulator and water described in the first aspect of the present application.

[0013] According to the fourth aspect of the present application, an application of the cutting fluid described in the third aspect of the present application in silicon wafer cutting is provided.

[0014] Technical effects of the present application:

[0015] For the modified dispersant provided by the present application, since both ends of the molecule are provided with saturated fatty long straight chains, and the middle main chain segment of 2,5-dimethyl-2,5-hexanediol can rotate flexibly through carbon-carbon single bonds, driving the saturated fatty long straight chains on both sides of the modified dispersant to fully extend, with low molecular chain folding degree and large free space, the dispersion performance of the system is effectively enhanced. When in use, the saturated fatty long straight chains on both sides can be coated and isolated, and the middle polymethyl main chain segment can ensure its penetration effect through rotation and moderate steric hindrance effect.

[0016] The cutting fluid provided by the present application is prepared by using the above-mentioned modified dispersant. Since the ratio of the ester group fragment in the modified dispersant to the saturated fatty long straight chain with appropriate carbon number is coordinated, while ensuring the dispersion performance, it can make the modified dispersant and the lubricant (such as alcohol compounds) better miscible, and avoid the precipitation of the dispersant caused by the high temperature of the fatty side chain with too high carbon number during cutting, which affects the cutting efficiency. It also avoids the problem that the fatty side chain with too low carbon number cannot be effectively coated and the dispersion performance is poor. Since the main component of the cutting fluid is an alcohol substance, it is easy to carry more mortar, enhancing the cutting efficiency, and the modified dispersant is more likely to stretch its branched chains in the system to achieve the purpose of completely dispersing and suspending particulate matter, such as making the silicon carbide micropowder not easy to settle in the system to ensure that the silicon carbide micropowder plays a sufficient grinding role during cutting. At the same time, since the cutting fluid contains a lubricant, the lubricity is enhanced, the silicon wafer can be cut better, and the actual wire breakage situation is reduced.

[0017] When the above-mentioned cutting fluid of the present application is used for silicon wafer cutting, in actual use, it is formulated with an abrasive (such as silicon carbide powder) to prepare a cutting mortar liquid. Due to the support of the saturated fatty long straight chain of the modified dispersant, the dispersion performance is excellent. Due to 2,5-dimethyl-2,5-hexanediol with a polymethyl structure as the central chain segment, it is beneficial to quickly penetrate into the cutting gap during the cutting process, achieving a good penetration effect. For the cutting mortar liquid system, the modified dispersant uses the saturated fatty long straight chain to quickly adsorb on the surface of the silicon powder. At the same time, based on the steric hindrance effect brought by the rotation of the long-chain structure configuration, the silicon powder is timely dispersed, preventing the silicon powder from aggregating into clusters. Therefore, when the cutting fluid provided by the present application is applied to silicon wafer cutting, it can ensure excellent dispersion while having a low cutting viscosity, enhancing the cutting efficiency, reducing the cutting wire breakage rate, and being beneficial to improving the finished product rate of silicon wafer cutting. Brief Description of the Drawings

[0018] Figure 1 It is a graph showing the results of the dispersion performance test of the embodiments of the present application.

[0019] Figure 2 It is a graph showing the results of the dispersion performance test of the comparative examples of the present application. Detailed Embodiments

[0020] Exemplary embodiments will be described more fully hereinafter. However, the exemplary embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more complete and comprehensive, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present application.

[0021] In a first aspect, the present application provides a modified dispersant, the structural formula of which is shown in Formula 1:

[0022]

[0023] Wherein, each R1 is the same or different, and each independently selected from a straight-chain alkyl group having 19 to 29 carbon atoms.

[0024] In the present application, for the straight-chain alkyl group having 19 to 29 carbon atoms, the number of carbon atoms can be, for example, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29. Specific examples include, but are not limited to, -(n-C 19 H 39 )、-(n-C 20 H 41 )、-(n-C 21 H 43 )、-(n-C 22 H 45 )、-(n-C 23 H 47 )、-(n-C 24 H 49 )、-(n-C 25 H 51 )、-(n-C 26 H 53 )、-(n-C 27 H 55 )、-(n-C 28 H 57 )、-(n-C 29 H 59 ) etc.

[0025] In some embodiments, each R1 is the same or different and is independently selected from -(n-C 19 H 39 )、-(n-C 20 H 41 )、-(n-C 21 H 43 )、-(n-C 22 H 45 )、-(n-C 23 H 47 )、-(n-C 24 H 49 )、-(n-C 25 H 51 )、-(n-C 26 H 53 )、-(n-C 27 H 55 )、-(n-C 28 H 57 ) or -(n-C 29 H 59 ).

[0026] In some preferred embodiments, each R1 is the same or different and is independently selected from -(n-C 19 H 39 )、-(n-C 21 H 43 )、-(n-C 23 H 47 )、-(n-C 24 H 49 )、-(n-C 27 H 55 )、-(n-C 29 H 59 ).

[0027] In some preferred embodiments, each R1 is the same.

[0028] A second aspect of the present application provides a method for preparing the above-mentioned modified dispersant, comprising the following steps:

[0029] S1: Subject 2,5-dimethyl-2,5-hexanediol to a hydroxyl activation reaction to obtain a hydroxyl-activated alcohol reactant;

[0030] S2: Perform an esterification reaction on the linear alkyl carboxylic acid R1-COOH and the obtained hydroxyl-activated alcohol reactant to obtain the modified dispersant shown in Formula 1;

[0031] wherein, R1 has the same definition as in the first aspect of the present application.

[0032] In some embodiments, the linear alkyl carboxylic acid is selected from one or more of n - eicosanoic acid, n - heneicosanoic acid, n - docosanoic acid, n - tricosanoic acid, n - tetracosanoic acid, n - pentacosanoic acid, n - hexacosanoic acid, n - heptacosanoic acid, n - octacosanoic acid, n - nonacosanoic acid, and n - triacontanoic acid.

[0033] In some preferred embodiments, the linear alkyl carboxylic acid is selected from one or more of n - eicosanoic acid, n - docosanoic acid, n - tetracosanoic acid, n - pentacosanoic acid, n - octacosanoic acid, and n - triacontanoic acid.

[0034] In this application, when one linear alkyl carboxylic acid is added in step S2, in the structure of the prepared modified dispersant, R1 is the same; when two or more linear alkyl carboxylic acids are added in step S2, in the structure of the prepared modified dispersant, R1 is different.

[0035] In some embodiments, in step S1, under an anhydrous and anaerobic environment, a hydroxyl activator is used to carry out a hydroxyl activation reaction on 2,5 - dimethyl - 2,5 - hexanediol.

[0036] In some preferred embodiments, in step S1, under an anhydrous and anaerobic environment, the solution containing the hydroxyl activator is slowly dropped into the solution containing 2,5 - dimethyl - 2,5 - hexanediol to carry out the hydroxyl activation reaction.

[0037] In some preferred embodiments, the hydroxyl activator is selected from dibutyltin oxide (DBTO).

[0038] In some embodiments, the molar ratio of 2,5 - dimethyl - 2,5 - hexanediol to the hydroxyl activator is 1:2 to 1:3. Specifically, the molar ratio of 2,5 - dimethyl - 2,5 - hexanediol to the hydroxyl activator is 1:2, 1:2.15, 1:2.2, 1:2.47, 1:2.5, 1:2.63, 1:2.71, 1:2.8, 1:2.92, 1:3, or any value therebetween.

[0039] In some preferred embodiments, the molar ratio of 2,5 - dimethyl - 2,5 - hexanediol to the hydroxyl activator is 1:2 to 1:2.92.

[0040] In some embodiments, the temperature of the hydroxyl activation reaction is 25°C to 55°C, and the time is 6 h to 8 h.

[0041] In some embodiments, the molar ratio of 2,5-dimethyl-2,5-hexanediol to linear alkyl carboxylic acid is 1:2 to 1:3. Specifically, the molar ratio of 2,5-dimethyl-2,5-hexanediol to linear alkyl carboxylic acid is 1:2, 1:2.15, 1:2.2, 1:2.47, 1:2.5, 1:2.63, 1:2.71, 1:2.8, 1:2.92, 1:3, or any value therebetween.

[0042] In some preferred embodiments, the molar ratio of 2,5-dimethyl-2,5-hexanediol to linear alkyl carboxylic acid is 1:2 to 1:2.92.

[0043] In some preferred embodiments, the molar ratio of the hydroxyl activator to the linear alkyl carboxylic acid is 1:1.

[0044] In some embodiments, the temperature of the esterification reaction is 55 °C to 80 °C, and the time is 10 h to 14 h.

[0045] The above preparation method of the present application adopts simpler and milder process conditions, reducing the requirements for reaction equipment and energy consumption during the reaction preparation process.

[0046] The third aspect of the present application provides a cutting fluid, which includes the modified dispersant, lubricant, pH regulator and water described in the first aspect.

[0047] In the above cutting fluid, by mass, it includes the following components: 1 to 5 parts of the modified dispersant, 70 to 90 parts of the lubricant, 0.1 to 3 parts of the pH regulator, and 3 to 26 parts of water.

[0048] In some embodiments, the lubricant is selected from alcohol compounds.

[0049] In the present application, specific embodiments of the alcohol compounds include, but are not limited to, fatty alcohols, polyols, polyethylene glycols, polypropylene glycols, etc.

[0050] In some embodiments, the lubricant is selected from one or more of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, propylene glycol, glycerol, polyethylene glycol, polypropylene glycol, but is not limited thereto.

[0051] In some preferred embodiments, the lubricant is selected from one or more of 1-butanol, glycerol, propylene glycol, polyethylene glycol, polypropylene glycol.

[0052] In some embodiments, the pH regulator is selected from one or more of formic acid, 2-ethylbutyric acid, n-heptanoic acid, salicylic acid, glyceric acid, oxalic acid, phthalic acid, citric acid, succinic acid, but is not limited thereto.

[0053] In some preferred embodiments, the pH regulator is selected from one or more of 2-ethylbutyric acid, n-heptylic acid, salicylic acid, citric acid, and succinic acid.

[0054] In some embodiments, in the cutting fluid, by mass, the modified dispersant is 1 to 5 parts. For example, it is 1 part, 1.5 parts, 2 parts, 2.7 parts, 3 parts, 3.2 parts, 4 parts, 4.5 parts, or 5 parts, or any value therebetween. In some preferred embodiments, the modified dispersant is 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, or 5 parts.

[0055] In some embodiments, in the cutting fluid, by mass, the lubricant is 70 to 90 parts. For example, it is 70 parts, 75 parts, 77 parts, 80 parts, 81 parts, 83 parts, 88 parts, or 90 parts, or any value therebetween. In some preferred embodiments, the lubricant is 70 parts, 75 parts, 77 parts, 81 parts, 83 parts, or 90 parts.

[0056] In some embodiments, in the cutting fluid, by mass, the pH regulator is 0.1 to 3 parts. For example, it is 0.1 part, 0.2 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.4 parts, 2 parts, 2.6 parts, or 3 parts, or any value therebetween. In some preferred embodiments, the pH regulator is 0.1 part, 0.2 part, 0.3 part, 1 part, 2 parts, or 3 parts.

[0057] In some embodiments, in the cutting fluid, by mass, water is 3 to 26 parts. In some preferred embodiments, water is 3 parts, 14 parts, 17.2 parts, 19.8 parts, 23.4 parts, or 26 parts.

[0058] In the above cutting fluid of the present application, by adopting the modified dispersant described in the first aspect of the present application, the dispersion performance of the cutting fluid is effectively improved. At the same time, there is no need to additionally add other functional aids such as thickeners, surfactants, and defoamers in the cutting fluid system, reducing the viscosity of the cutting fluid system, reducing environmental pollution, and also reducing costs and equipment energy consumption.

[0059] Fourthly, the present application provides an application of the cutting fluid described in the third aspect in silicon wafer cutting.

[0060] Synthesis Example

[0061] Those skilled in the art should recognize that the chemical reactions described in this application can be used to appropriately prepare many substances of this application, and other methods for preparing the substances of this application are considered to be within the scope of this application. For example, the synthesis of non-illustrative compounds according to this application can be successfully completed by those skilled in the art through modification methods, such as appropriately protecting interfering groups, by using other known reagents in addition to those described in this application, or making some conventional modifications to the reaction conditions. Compounds for which the synthesis method is not mentioned in this application are all raw material products obtained through commercial channels. The synthesis method of the modified dispersant of this application will be specifically described below in combination with synthesis examples, but this application is not limited thereby.

[0062] Synthesis Example 1

[0063] Hydroxyl activation reaction: Take a 200 mL three-necked flask, thoroughly remove water and oxygen, add 2,5-dimethyl-2,5-hexanediol (5.00 g, 0.0342 mol), and then add 50 mL of tetrahydrofuran (THF). Stir well until completely dissolved. Dissolve dibutyltin oxide (DBTO, 0.0684 mol, 17.02 g) completely in 50 mL of THF. Control the temperature to 25 °C, and very slowly drop the mixed solution containing 2,5-dimethyl-2,5-hexanediol into the mixed solution containing DBTO, and then carry out the hydroxyl activation reaction at 25 °C for 8 h. After the reaction is completed, it is recorded as the reaction solution to be awaited for the next reaction.

[0064] Esterification reaction: Dissolve n-triacontane carboxylic acid (n-C 29 H 59 -COOH, 0.0684 mol, 30.97 g) in 150 mL of toluene. Transfer the reaction solution to be awaited from the previous step into a 250 mL reaction flask, heat up to 80 °C, and slowly drop the mixed solution containing n-triacontane carboxylic acid into the reaction solution to be awaited, and then carry out the esterification reaction at 80 °C. After reacting for 14 h, evaporate the solvent, and then carry out column chromatography with n-hexane. Concentrate the column eluate under reduced pressure to obtain modified dispersant 1-1 (30.25 g, yield: 87.05%), and its structural formula is Synthesis Example 2

[0065] Hydroxyl activation reaction: Take a 200 mL three-necked flask, thoroughly remove water and oxygen, add 2,5-dimethyl-2,5-hexanediol (5.00 g, 0.0342 mol), and then add 50 mL of THF. Stir well until completely dissolved. Dissolve DBTO (0.09 mol, 22.40 g) completely in 50 mL of THF. Control the temperature to 45 °C, and very slowly drop the mixed solution containing 2,5-dimethyl-2,5-hexanediol into the mixed solution containing DBTO, and then carry out the hydroxyl activation reaction at 45 °C for 6 h. After the reaction is completed, it is recorded as the reaction solution to be awaited for the next reaction.

[0066] Esterification reaction: Dissolve n - docosanoic acid (n - C 19 H 39 -COOH, 0.09 mol, 28.13 g) in 120 mL of toluene. Transfer the reaction solution from the previous step to a 250 mL reaction flask, heat it to 60 °C, slowly drop the mixed solution containing n - docosanoic acid into the reaction solution, and then carry out the esterification reaction at 60 °C. After reacting for 10 h, evaporate the solvent, then perform column chromatography with n - hexane, and concentrate the eluate under reduced pressure to obtain modified dispersant 1 - 2 (22.15 g, yield: 88.03%), and its structural formula is Synthesis Example 3

[0067] Hydroxyl activation reaction: Take a 200 mL three - necked flask, thoroughly remove water and oxygen, add 2,5 - dimethyl - 2,5 - hexanediol (5.00 g, 0.0342 mol), and then add 50 mL of THF, and stir well until completely dissolved. Take DBTO (0.1 mol, 24.89 g) and dissolve it completely in 50 mL of THF. Control the temperature to 55 °C, and extremely slowly drop the mixed solution containing 2,5 - dimethyl - 2,5 - hexanediol into the mixed solution containing DBTO, and then carry out the hydroxyl activation reaction at 55 °C for 8 h. After the reaction is completed, it is recorded as the reaction solution to be used for the next step of the reaction.

[0068] Esterification reaction: Dissolve n - pentacosanoic acid (n - C 24 H 49 -COOH, 0.1 mol, 38.27 g) in 130 mL of toluene. Transfer the reaction solution from the previous step to a 250 mL reaction flask, heat it to 55 °C, slowly drop the mixed solution containing n - pentacosanoic acid into the reaction solution, and then carry out the esterification reaction at 55 °C. After reacting for 10 h, evaporate the solvent, then perform column chromatography with n - hexane, and concentrate the eluate under reduced pressure to obtain modified dispersant 1 - 3 (26.36 g, yield: 88.01%), and its structural formula is Synthesis Example 4

[0069] Hydroxyl activation reaction: Take a 200 mL three - necked flask, thoroughly remove water and oxygen, add 2,5 - dimethyl - 2,5 - hexanediol (5.00 g, 0.0342 mol), and then add 50 mL of THF, and stir well until completely dissolved. Take DBTO (0.075 mol, 18.67 g) and dissolve it completely in 50 mL of THF. Control the temperature to 50 °C, and extremely slowly drop the mixed solution containing 2,5 - dimethyl - 2,5 - hexanediol into the mixed solution containing DBTO, and then carry out the hydroxyl activation reaction at 50 °C for 7 h. After the reaction is completed, it is recorded as the reaction solution to be used for the next step of the reaction.

[0070] Esterification reaction: Dissolve n - docosanoic acid (n - C 21 H 43-COOH (0.086 mol, 29.29 g) was dissolved in 130 mL of toluene. The reaction solution to be used in the previous step was transferred to a 250 mL reaction flask, and the temperature was raised to 70 °C. After the mixed solution containing n-docosanoic acid was slowly dropped into the reaction solution to be used, the esterification reaction was carried out at 70 °C. After 12 h of reaction, it was taken out, the solvent was evaporated to dryness, and then column chromatography was carried out with n-hexane. The column eluate was concentrated under reduced pressure to obtain modified dispersant 1-4 (25.03 g, yield: 92.42%), and its structural formula is 1 H NMR (400 MHz, C2D6SO) δ ppm: 2.39 - 2.25 (m, 4H), 1.65 (q, 4H), 1.43 (s, 12H), 1.32 - 1.21 (m, 76H), 0.75 - 0.66 (m, 6H).

[0071] Synthesis Example 5

[0072] Hydroxyl activation reaction: Take a 200 mL three-necked flask, thoroughly remove water and oxygen, add 2,5-dimethyl-2,5-hexanediol (5.00 g, 0.0342 mol), and then add 50 mL of THF. Stir well until completely dissolved. Take DBTO (0.1 mol, 24.89 g) and dissolve it completely in 50 mL of THF. Control the temperature to 35 °C. After the mixed solution containing 2,5-dimethyl-2,5-hexanediol was extremely slowly dropped into the mixed solution containing DBTO, the hydroxyl activation reaction was carried out at 35 °C for 7 h. After the reaction was completed, it was recorded as the reaction solution to be used for the next step reaction.

[0073] Esterification reaction: n-Octacosanoic acid (n-C 27 H 55 -COOH, 0.082 mol, 34.82 g) was dissolved in 140 mL of toluene. The reaction solution to be used in the previous step was transferred to a 250 mL reaction flask, and the temperature was raised to 65 °C. After the mixed solution containing n-octacosanoic acid was slowly dropped into the reaction solution to be used, the esterification reaction was carried out at 65 °C. After 14 h of reaction, the solvent was evaporated to dryness, and then column chromatography was carried out with n-hexane. The column eluate was concentrated under reduced pressure to obtain modified dispersant 1-5 (29.25 g, yield: 89.09%), and its structural formula is Synthesis Example 6

[0074] Hydroxyl activation reaction: Take a 200 mL three-necked flask, thoroughly remove water and oxygen, add 2,5-dimethyl-2,5-hexanediol (5.00 g, 0.0342 mol), and then add 50 mL of THF. Stir thoroughly until completely dissolved. Take DBTO (0.075 mol, 18.67 g) and dissolve it completely in 50 mL of THF. Control the temperature to 40 °C. Slowly drop the mixed solution of 2,5-dimethyl-2,5-hexanediol into the mixed solution of DBTO extremely slowly, and then carry out the hydroxyl activation reaction at 40 °C for 6 h. After the reaction is completed, it is recorded as the reaction solution to be awaited for the next reaction.

[0075] Esterification reaction: Dissolve n-tetracosanoic acid (n-C 23 H 47 -COOH, 0.09 mol, 33.18 g) in 130 mL of toluene. Transfer the reaction solution to be awaited from the previous step into a 250 mL reaction flask, heat up to 75 °C, slowly drop the mixed solution of n-tetracosanoic acid into the reaction solution to be awaited, and then carry out the esterification reaction at 75 °C. After reacting for 12 h, evaporate the solvent, and then carry out column chromatography with n-hexane. Concentrate the column eluate under reduced pressure to obtain modified dispersant 1-6 (24.06 g, yield: 82.99%), and its structural formula is

[0076] Comparative Synthesis Example 1

[0077] The difference from Synthesis Example 1 is only that n-hentriacontanoic acid (n-C 30 H 61 -COOH, 0.0684 mol, 31.93 g) is used for the esterification reaction to obtain comparative dispersant DB-1 (25.23 g, yield: 70.67%), and its structural formula is

[0078] Comparative Synthesis Example 2

[0079] The difference from Synthesis Example 1 is only that n-nonadecanoic acid (n-C 18 H 37 -COOH, 0.0684 mol, 20.42 g) is used for the esterification reaction to obtain comparative dispersant DB-2 (16.39 g, yield: 67.44%), and its structural formula is

[0080] Comparative Synthesis Example 3

[0081] The difference from Synthesis Example 1 is only that decyltetradecanoic acid ( 0.0684 mol, 25.21 g) is used for the esterification reaction to obtain comparative dispersant DB-2 (20.16 g, yield 68.54%), and its structural formula is

[0082] Example 1

[0083] The cutting fluid comprises the following components:

[0084] 1.5 parts of modified dispersant 1-1, 75 parts of polyethylene glycol, 0.1 part of 2-ethylbutyric acid, and 23.4 parts of water.

[0085] The preparation steps are as follows: at 25°C, first add 2-ethylbutyric acid to water, and stir at a stirring rate of 300 r / min for 10 minutes at high speed. After 2-ethylbutyric acid is completely dissolved, add modified dispersant 1-1 and stir for 10 minutes at a stirring rate of 350 r / min. After the stirring is completed, slowly add polyethylene glycol and stir for 30 minutes.

[0086] Example 2

[0087] The cutting fluid comprises the following components:

[0088] 1.5 parts of modified dispersant 1-2, 81 parts of polypropylene glycol, 0.3 part of succinic acid, and 17.2 parts of water.

[0089] The preparation steps are as follows: at 25°C, first add succinic acid to water, and stir at a stirring rate of 300 r / min for 10 minutes at high speed. After succinic acid is completely dissolved, add modified dispersant 1-2 and stir for 10 minutes at a stirring rate of 350 r / min. After the stirring is completed, slowly add polypropylene glycol and stir for 30 minutes.

[0090] Example 3

[0091] The cutting fluid comprises the following components:

[0092] 3 parts of modified dispersant 1-3, 77 parts of glycerol, 0.2 part of n-heptanoic acid, and 19.8 parts of water.

[0093] The preparation steps are as follows: at 25°C, first add n-heptanoic acid to water, and stir at a stirring rate of 200 r / min for 10 minutes at high speed. After n-heptanoic acid is completely dissolved, add modified dispersant 1-3 and stir for 10 minutes at a stirring rate of 350 r / min. After the stirring is completed, slowly add glycerol and stir for 30 minutes.

[0094] Example 4

[0095] The cutting fluid comprises the following components:

[0096] 2 parts of modified dispersant 1-4, 83 parts of propylene glycol, 1 part of n-heptanoic acid, and 14 parts of water.

[0097] The preparation steps are as follows: At 25°C, first add n-heptanoic acid to water, and stir at a stirring rate of 300 r / min for 10 minutes at high speed. After the n-heptanoic acid is completely dissolved, add the modified dispersant 1-4 at a stirring rate of 350 r / min and stir for 10 minutes. After the stirring is completed, then slowly add propylene glycol and stir for 30 minutes.

[0098] Example 5

[0099] The cutting fluid comprises the following components:

[0100] 5 parts of the modified dispersant 1-5, 90 parts of 1-butanol, 2 parts of citric acid, and 3 parts of water.

[0101] The preparation steps are as follows: At 25°C, first add citric acid to water, and stir at a stirring rate of 300 r / min for 10 minutes at high speed. After the citric acid is completely dissolved, add the modified dispersant 1-5 at a stirring rate of 350 r / min and stir for 10 minutes. After the stirring is completed, then slowly add 1-butanol and stir for 30 minutes.

[0102] Example 6

[0103] The cutting fluid comprises the following components:

[0104] 1 part of the modified dispersant 1-6, 70 parts of propylene glycol, 3 parts of salicylic acid, and 26 parts of water.

[0105] The preparation steps are as follows: At 25°C, first add salicylic acid to water, and stir at a stirring rate of 300 r / min for 10 minutes at high speed. After the salicylic acid is completely dissolved, add the modified dispersant 1-6 at a stirring rate of 350 r / min and stir for 10 minutes. After the stirring is completed, then slowly add propylene glycol and stir for 30 minutes.

[0106] Comparative Example 1

[0107] The difference from Example 1 is only that the dispersant used is DB-1, and the obtained product is denoted as Comparative Cutting Fluid-1.

[0108] Comparative Example 2

[0109] The difference from Example 1 is only that the dispersant used is DB-2, and the obtained product is denoted as Comparative Cutting Fluid-2.

[0110] Comparative Example 3

[0111] The difference from Example 1 is only that the dispersant used is DB-3, and the obtained product is denoted as Comparative Cutting Fluid-3.

[0112] Comparative Example 4

[0113] The difference from Example 1 is only that ethylene glycol oleate (C 20 H 38 O3, with the structural formula of ) is used as the dispersant, and the obtained product is denoted as Comparative Cutting Fluid - 4.

[0114] In the above embodiments of the present application, deionized water is used to prepare the cutting fluid.

[0115] Performance and Index Detection

[0116] Test Method

[0117] First, the cutting fluid prepared in the examples or comparative examples of the present application is mixed with silicon carbide powder at a weight ratio of 1:1 and stirred for 4 hours to obtain a cutting slurry, and the obtained cutting slurry is used for silicon wafer cutting. Specifically, in the present application, through the following test items, the effects of the cutting fluids prepared in the above examples or comparative examples are evaluated as follows:

[0118] Viscosity: For the slurry before and after cutting the silicon wafer, use a rotational viscometer to measure the viscosity values before and after cutting at 15 - 30 mPa·s (25 °C), and execute the test standard GB / T 7193.1 - 1989.

[0119] Defoaming time: Prepare a 1000 mL 5 wt% dilution by mixing the cutting fluid and water at a mass ratio of 5:100, stir it at 23 °C for 15 min to make it foam, and then measure its defoaming time. Test instrument: HCR - 700 type metal cutting fluid antifoaming tester.

[0120] Dispersion performance: Take 200 g of the cutting fluid, mix it with silicon carbide powder at a weight ratio of 1:1, stir for 4 h, pour it into a 100 ml graduated cylinder, and observe the sedimentation amount after 24 h (25 °C). The judgment basis is that the smaller the sedimentation amount, the better the performance.

[0121] Penetration time: Prepare a 1000 mL 5 wt% dilution by mixing the cutting fluid and water at a mass ratio of 5:100, and use the canvas sedimentation permeability test method to detect its wetting time at 25 ± 1 °C.

[0122] Wire breakage rate: Use the slurry for silicon wafer cutting and count the wire breakage rate (%) during the cutting process.

[0123] Measurement of COD value: Measure the COD value of the cutting fluid by the potassium dichromate method. The judgment basis is that the lower the COD value, the better the environmental protection performance.

[0124] Test Results

[0125] The test results of the dispersion performance of the cutting fluids in Examples 1 - 6 of the present application are as Figure 1As shown in the figure, (1-a) in the figure is the dispersion performance test result of Example 1, (1-b) is the dispersion performance test result of Example 2, (1-c) is the dispersion performance test result of Example 3, (1-d) is the dispersion performance test result of Example 4, (1-e) is the dispersion performance test result of Example 5, and (1-f) is the dispersion performance test result of Example 6. The dispersion performance test results of the cutting fluids of Comparative Examples 1 to 4 of the present application are as follows Figure 2 As shown in the figure, (2-a) in the figure is the dispersion performance test result of Comparative Example 1, (2-b) is the dispersion performance test result of Comparative Example 2, (2-c) is the dispersion performance test result of Comparative Example 3; (2-d) is the dispersion performance test result of Comparative Example 4. It can be seen from the dispersion performance results of Examples 1 to 6 and Comparative Examples 1 to 4 of the present application that the dispersion performance of the silicon carbide powder using the cutting fluid of the present application is significantly better than that of the comparative cutting fluid, and the sedimentation amount of the examples is at least reduced by 26.2% compared with the comparative examples.

[0126] The viscosity, defoaming time, dispersion performance, penetration time, wire breakage rate, and COD value of Examples 1 to 6 and Comparative Examples 1 to 4 were measured according to the above standard test methods. The detailed test results are shown in Table 1 below.

[0127] Table 1

[0128]

[0129] According to the experimental results in the above table, compared with Comparative Examples 1 to 4, the cutting fluids prepared in Examples 1 to 6 of the present application have almost no change in the viscosity value before and after cutting, the defoaming time and penetration time are significantly shortened, and the sedimentation height in the dispersion performance is also significantly reduced. This shows that the cutting fluid of the present application can still maintain the low-viscosity characteristic unchanged even after use, has excellent performance of recycling and reusing, and at the same time has excellent dispersion performance, which will not cause uneven mortar and affect the yield. At the same time, because the main component of the system is alcohol, the lubrication stability of the system can be ensured, and finally the probability of wire breakage and jumper is reduced. At the same time, the cutting fluid of the present application has a relatively low COD value and is more environmentally friendly and stable.

[0130] Overall, this is because the modified dispersant active component is first used in the cutting fluid of the present application. The polymethyl structure in the modified dispersant can play a good penetration role, which is beneficial for the dispersant to help alcohol compounds enter into tiny gaps, improving the cutting performance. At the same time, the presence of its saturated fatty long straight chain can effectively wrap and support the abrasive. In the mortar system, it can freely extend and change direction, enabling the abrasive to be well supported in the system, reducing the probability of the abrasive leaking from the space gap and being less likely to settle and aggregate. The resulting cutting fluid has stable properties and will not cause a change in the pH value of the system during use, thus not affecting the mutual repulsion of silicon carbide (micro) powder carrying the same surface charge and can maintain a good suspension and dispersion effect, and can also have good use performance under extreme conditions. However, as demonstrated by the comparative dispersant components in the comparative examples, for example, Comparative Example 2 adopted a shorter straight-chain structure, Comparative Example 3 adopted a shorter branched-chain structure, and Comparative Example 4 adopted a unilateral straight-chain structure. When these structures are used as dispersing group fragments, they are not sufficient to achieve effective dispersion performance. This may be because such chain structures fail to effectively coat the silicon carbide particles, greatly reducing the dispersion performance. The exposed silicon carbide surface will cause particle aggregation, resulting in an increase in the cutting wire breakage rate. For example, Comparative Example 1 adopted a longer saturated carbon chain, and its dispersion performance was also significantly reduced. This may be because the longer saturated fatty straight chain will lead to poor solubility, making it unable to effectively coat the silicon carbide. This is more likely to cause the precipitation of the dispersant under the high-temperature working conditions in actual cutting use, and all of these will lead to an increase in the wire breakage rate after cutting.

[0131] The preferred embodiments of the present invention have been described in detail above. However, the present application is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present application, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A modified dispersant, characterized in that, Its structural formula is shown in Formula 1: Among them, each R1 is the same or different and is independently selected from straight-chain alkyl groups having 19 to 29 carbon atoms.

2. The modified dispersant according to claim 1, wherein Each R1 is the same or different and is independently selected from -(n-C 19 H 39 )、-(n-C 20 H 41 )、-(n-C 21 H 43 )、-(n-C 22 H 45 )、-(n-C 23 H 47 )、-(n-C 24 H 49 )、-(n-C 25 H 51 )、-(n-C 26 H 53 )、-(n-C 27 H 55 )、-(n-C 28 H 57 ) or -(n-C 29 H 59 ).

3. The modified dispersant according to claim 1, wherein, Each R1 is the same or different and is independently selected from -(n-C 19 H 39 )、-(n-C 21 H 43 )、-(n-C 23 H 47 )、-(n-C 24 H 49 )、-(n-C 27 H 55 )、-(n-C 29 H 59 ).

4. The preparation method of the modified dispersant according to any one of claims 1 to 3, characterized in that, It includes the following steps: Subject 2,5-dimethyl-2,5-hexanediol to a hydroxyl activation reaction to obtain a hydroxyl-activated alcohol reactant; Subject the straight-chain alkyl carboxylic acid RCOOH to an esterification reaction with the obtained hydroxyl-activated alcohol reactant to obtain a modified dispersant as shown in Formula 1; Among them, R1 has the same definition as in Claim 1.

5. A cutting fluid, which comprises the modified dispersant according to any one of Claims 1 to 3, a lubricant, a pH regulator and water.

6. The cutting fluid according to claim 5, characterized in that, It includes the following components: The modified dispersant is 1 to 5 parts, the lubricant is 70 to 90 parts, the pH regulator is 0.1 to 3 parts, and water is 3 to 26 parts.

7. The cutting fluid according to claim 5, characterized in that, The lubricant is selected from alcohol compounds; Preferably, the lubricant is selected from one or more of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, propylene glycol, glycerol, polyethylene glycol, and polypropylene glycol.

8. The cutting fluid according to claim 5, characterized in that, The pH regulator is selected from one or more of formic acid, 2-ethylbutyric acid, n-heptylic acid, salicylic acid, glyceric acid, oxalic acid, phthalic acid, citric acid, and succinic acid.

9. Use of the cutting fluid according to any one of Claims 5 to 8 in wafer cutting.

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