Environment-friendly metal cutting oil based on neopentyl polyol ester

Abstract

The invention discloses environment-friendly metal cutting oil based on neopentyl polyol ester, and belongs to the technical field of metal cutting oil. The cutting oil consists of base oil and an additive, wherein the base oil is a mixture of neopentyl polyol ester (NPE-3) and diisooctyl sebacate; the additives comprise fatty cluster phosphate amine salt (T6450), a borate additive and a vulcanization extreme pressure additive; the borate system additive is octadecyloxy nitrogen calcium borate (T366) or octadecyloxy sulfo nano calcium borate (T365) with the addition amount of 0.04 to 1.8 percent; the sulfurized extreme pressure additive is sulfurized fatty acid ester and dialkyl pentasulfide (Rc2540). The cutting oil has excellent high-temperature and low-temperature bearing capacity and high abrasion resistance, the bearing capacity (Pb) of the cutting oil can reach 1050 N or above, the long abrasion value (Db) of the cutting oil can be smaller than 0.38 mm, and the cutting oil is non-toxic and suitable for various metals.

Description

Technical Field

[0001] The present invention relates to the technical field of metal cutting oils, and particularly relates to an environment-friendly metal cutting oil based on neopentyl polyol ester. Background Art

[0002] The base oils used in traditional cutting fluids are mostly refined mineral oils, which have mature processes and low prices, but their biodegradability is poor, and they can remain in water and soil for a long time, damaging the normal ecology. The ester group in the molecular structure of synthetic esters is easy to adsorb on the metal surface, forming a firm lubricating film, having good anti-friction and anti-wear effects, and having good biodegradability. With the continuous improvement of the requirements for the use performance and environmental hygiene of cutting oils, synthetic esters are increasingly widely used as effective alternative components to mineral oils in cutting fluids.

[0003] Different types of synthetic esters have different applications in cutting fluid products. Neopentyl polyol esters (NPE-3) have excellent properties. They refer to a class of synthetic esters in which the ester group adjacent position in the molecular structure is a quaternary carbon atom, mainly including neopentyl glycol esters, trimethylolpropane esters and pentaerythritol esters. Among ester oils, polyol esters have the best performance and the best lubricating performance. The reason is that there is no hydrogen on the β-carbon atom in the molecular structure of neopentyl polyol esters, and the bulky neopentyl group provides a good space shielding effect for the ester group, increasing the activation energy required for the thermal decomposition of neopentyl polyol to generate free radicals. This makes its thermal decomposition temperature usually about 50°C higher than that of dibasic acid esters, and at the same time makes its antioxidant performance better than that of general diesters; secondly, the lubricity of neopentyl polyol esters is better than that of diesters and mineral oils, far better than that of polyalphaolefins (PAO), and although the long- and short-chain mixed esters have a small viscosity, they have the smallest friction coefficient; thirdly, neopentyl polyol esters have good viscosity-temperature properties and evaporation properties. Due to the above advantages, neopentyl polyol esters have been widely used in the lubrication field. For example, jet engine lubricating oil, automobile engine lubricating oil, precision instrument oil, lubricating grease base oil for protecting machine parts, metal processing fluids (such as cutting fluids), etc.

[0004] The additives in metal cutting oils also cause pollution to the environment in various aspects. For example, chlorinated paraffin, used as an extreme pressure and anti-wear agent in cutting fluid components, has been prohibited from use due to its carcinogenic risk and environmental pollution during post-treatment. Sodium nitrite and others are added as water-soluble rust inhibitors. They react with metals to form an insoluble and dense oxide film on their surfaces, preventing the electrochemical corrosion process of metals. Most of these rust inhibitors are electrolytes, which are toxic, difficult to post-treat, and tend to be replaced. Molybdate rust inhibitors are non-toxic and pollution-free, but they are relatively expensive; organic phosphorus-containing rust inhibitors have a certain corrosive effect on copper and its alloys, and in addition, they can cause eutrophication of water bodies. Therefore, the main development trend is to develop low-phosphorus or phosphorus-free rust inhibitors. Adding anti-corrosion and bactericidal agents to metal cutting oils can effectively kill and inhibit microorganisms. However, in recent years, due to increasingly strict environmental protection regulations, commonly used phenolic and formaldehyde-releasing bactericides have been restricted.

[0005] In view of the dual pressures of traditional cutting oils facing increasingly stringent process requirements and increasingly strict environmental protection regulations, it is imperative to improve and upgrade their technologies. This not only requires continuously improving the processing performance of cutting fluids, but more importantly, it should focus on researching, developing, and promoting the application of low-toxic and low-pollution environmentally friendly cutting oil products. Summary of the Invention

[0006] Aiming at the above deficiencies existing in the prior art, the purpose of the present invention is to provide an environmentally friendly metal cutting oil based on neopentyl polyol ester. This cutting fluid has excellent high-load and high anti-wear performance at high and low temperatures, is non-toxic, and is suitable for cutting oils of various metals.

[0007] To achieve the above purpose, the technical solutions adopted by the present invention are as follows:

[0008] An environmentally friendly metal cutting oil based on neopentyl polyol ester, which is composed of a base oil and additives, wherein: the base oil is a mixture of neopentyl polyol ester (NPE-3) and diisooctyl sebacate; the additives include phosphate ester amine salt extreme pressure additives, borate-based additives, and sulfurized extreme pressure additives.

[0009] The phosphate ester amine salt extreme pressure additive is aliphatic phosphate ester amine salt (T6450); the borate-based additive is calcium octadecyloxy azoborate (T366) or calcium octadecyloxy thionano borate (T365); the sulfurized extreme pressure additive is sulfurized fatty acid ester and dialkyl pentasulfide (Rc2540).

[0010] Further, in this cutting oil, the addition amount of the phosphoric acid ester amine salt extreme pressure additive is 0.15 - 0.85% (preferably 0.20 - 0.80%) of the weight of the base oil; the addition amount of the borate series additive is 0.04 - 1.8% of the weight of the base oil; the ratio of the addition amount of the phosphoric acid ester amine salt extreme pressure additive to the addition amount of the borate series additive is greater than 0.3; the addition amount of the sulfurized fatty acid ester is 0.03 - 1.2% of the weight of the base oil, and the addition amount of the dialkyl pentasulfide (Rc2540) is 0.12 - 0.80% of the weight of the base oil.

[0011] Further, after optimizing the formula of this cutting oil, when the base oil is neopentyl polyol ester, the preferred formula I of this cutting oil is: the addition amount of the phosphoric acid ester amine salt extreme pressure additive is 0.40 - 0.85 wt.% of the weight of the base oil, and the addition amount of the borate series additive is 0.05 - 0.35 wt.% of the weight of the base oil; the addition amount of the sulfurized fatty acid ester is 0.03 - 0.75 wt.% of the weight of the base oil, and the addition amount of the dialkyl pentasulfide (Rc2540) is 0.25 - 0.75 wt.% of the weight of the base oil; the load-carrying capacity (Pb) of the cutting oil of this formula I is greater than 900 N, and the long grinding value is less than 0.42 mm;

[0012] When the base oil is a mixture of neopentyl polyol ester and diisooctyl sebacate in a volume ratio of 1:1, the preferred formula II of this cutting oil is: the addition amounts (wt.%) of the phosphoric acid ester amine salt extreme pressure additive, borate series additive, sulfurized fatty acid ester, and dialkyl pentasulfide (Rc2540) in the base oil are 0.02 - 0.10%, 0.04 - 0.25%, 0.03 - 0.75%, 0.03 - 0.75% respectively, or the addition amounts (wt.%) of the phosphoric acid ester amine salt extreme pressure additive, borate series additive, sulfurized fatty acid ester, and dialkyl pentasulfide (Rc2540) in the base oil are 0.35 - 0.5%, 1.20 - 1.60%, 0.60 - 0.80%, 0.65 - 0.85% respectively. The load-carrying capacity (Pb) of the cutting oil of this formula II is greater than 1050 N, and the long grinding value is less than 0.38 mm.

[0013] Further, in the base oil, the volume proportion of neopentyl polyol ester (NPE - 3) is 40 - 100%.

[0014] Further, the aliphatic phosphoric acid ester amine salt (T6450) is a mixture of a class of phosphoric acid ester amine salts, and its structural general formula is as shown in formula (1):

[0015]

[0016] In formula (1), R is a C5-C8 aliphatic alkyl group, and NH2R` is a primary amine of a C12-C14 alkyl group.

[0017] Furthermore, the preparation process of this environmentally friendly cutting fluid is as follows: Add phosphate ester amine salt extreme pressure additives, borate additives, and sulfurized extreme pressure additives to the base oil in proportion. After stirring evenly, heat it at 75-100 °C for 30-60 minutes to obtain the environmentally friendly metal cutting oil.

[0018] The design mechanism and beneficial effects of the present invention are as follows:

[0019] 1. The quality of the base oil directly affects the performance of the cutting oil, and the thermal stability of the cutting oil is closely related to its structure. The environmentally friendly metal cutting oil of the present invention uses neopentyl polyol ester as the main base oil, and neopentyl polyol ester accounts for more than 40 vol.%. Neopentyl polyol ester has a high viscosity and excellent lubrication performance. Dioctyl sebacate can also be appropriately added to the base oil. Dioctyl sebacate has a low viscosity and good fluidity. As a cutting oil, it has excellent cleaning ability and good lubrication performance. Using two base oils mixed to form a new base oil can have the performance of both oils at the same time. The base oil used in the present invention has a moderate viscosity and the characteristics of being non-toxic and biodegradable, which is environmentally friendly.

[0020] 2. The dosage of additives in the cutting oil is small, and its content usually does not exceed 2% of the overall cutting oil. Even so, just relying on this small proportion of additives determines the quality of a cutting oil product. The addition amount of additives should be appropriate. Too little will affect the physical and chemical properties of the cutting oil, and too much will make the physical and chemical properties of the cutting oil unsatisfactory. By adding specific proportions of aliphatic phosphate ester amine salt (T6450), calcium octadecyloxy azoborate (T366) or calcium octadecyloxy thionano borate (T365), sulfurized fatty acid ester and dialkyl pentasulfide (Rc2540) to the mixed base oil in the present invention, the compounded additives and the base oil act synergistically to improve the tribological properties and physical and chemical properties of the cutting oil.

[0021] 3. The environmentally friendly metal cutting fluid of the present invention has excellent high-load and anti-wear properties at high and low temperatures and excellent environmental protection properties.

[0022] 4. When the base oil is neopentyl polyol ester in the present invention, the optimized formula I of the cutting oil is: the addition amounts of phosphate ester amine salt extreme pressure additives, borate additives, sulfurized fatty acid ester and dialkyl pentasulfide are 0.40-0.85 wt.%, 0.05-0.35 wt.%, 0.03-0.75 wt.%, 0.25-0.75 wt.% of the base oil respectively; the load-carrying capacity (Pb) of the cutting oil of this formula I is greater than 900 N, and the long wear value is less than 0.42 mm.

[0023] When the base oil is a mixture of neopentyl polyol ester and diisooctyl sebacate in a volume ratio of 1:1, the preferred formulation II of the cutting oil is as follows: the addition amounts (wt.%) of the phosphate ester amine salt extreme pressure additive, borate-based additive, sulfurized fatty acid ester, and dialkyl pentasulfide (Rc2540) in the base oil are 0.02 - 0.10%, 0.04 - 0.25%, 0.03 - 0.75%, 0.03 - 0.75% respectively, or the addition amounts (wt.%) of the phosphate ester amine salt extreme pressure additive, borate-based additive, sulfurized fatty acid ester, and dialkyl pentasulfide (Rc2540) in the base oil are 0.35 - 0.5%, 1.20 - 1.60%, 0.60 - 0.80%, 0.65 - 0.85% respectively. The load-carrying capacity (Pb) of the cutting oil of this formulation II is greater than 1050 N, and the long grinding value is less than 0.38 mm. Description of the Drawings

[0024] Figure 1(a) is a SEM photograph of the steel ball wear scar magnified 500 times in the four-ball test of the cutting oil sample in Example 1 (F = 294 N, T = 60 min).

[0025] Figure 1(b) is a SEM photograph of the steel ball wear scar magnified 2000 times in the four-ball test of the cutting oil sample in Example 1 (F = 294 N, T = 60 min).

[0026] Figure 2 For energy spectrum analysis of the typical areas of the surface wear marks in Figure 1, the element contents of the corresponding areas are obtained; among them: (a) the morphology map of different areas marked; (b) the element contents at position 75 of the spectrum; (c) the element contents at position 76 of the spectrum; (d) the element contents at position 77 of the spectrum.

[0027] Figure 3 It is a SEM photograph of the steel ball wear scar in the four-ball test of the cutting oil sample in Example 8 (F = 294 N, T = 60 min); among them: (a) and (b) are the wear scar morphologies magnified 500 times and 2000 times respectively.

[0028] Figure 4 For Figure 3 energy spectrum analysis of the typical areas of the surface wear marks in, the element contents of the corresponding areas are obtained; among them: (a) the morphology map of different areas marked; (b) the element contents at position 79 of the spectrum; (c) the element contents at position 80 of the spectrum; (d) the element contents at position 81 of the spectrum; (e) the element contents at position 82 of the spectrum.

[0029] Figure 5 It is a photograph of normal guinea pig eyes (female in the upper picture, male in the lower picture).

[0030] Figure 6 Photographs of guinea pig eyes at 3 min after the eye drop test of the cutting oil in Example 1 (female in the upper picture, male in the lower picture).

[0031] Figure 7 Photographs of guinea pig eyes at 1 h after the start of the eye drop test of the cutting oil in Example 1 (female in the upper picture, male in the lower picture).

[0032] Figure 8 Photographs of guinea pig eyes at 24 h after the start of the eye drop test of the cutting oil in Example 1 (female in the upper picture, male in the lower picture).

[0033] Figure 9 Photographs of the back of guinea pigs on the 4th day of the cutting oil application test in Example 1 (female in the upper picture, male in the middle picture, and young in the lower picture).

[0034] Figure 10 Photographs of the back of guinea pigs on the 8th day of the cutting oil application test in Example 1 (female in the upper picture, male in the middle picture, and young in the lower picture).

[0035] Figure 11 Photographs of the back of guinea pigs on the 12th day of the cutting oil application test in Example 1 (female in the upper picture, male in the middle picture, and young in the lower picture).

[0036] Figure 12 Photographs of the back of guinea pigs on the 16th day of the cutting oil application test in Example 1 (female in the upper picture, male in the middle picture, and young in the lower picture).

[0037] Figure 13 Photographs of guinea pig eyes at 24 h after the start of the eye drop test of the cutting oil in Example 8 (female in the upper picture, male in the middle picture, and young in the lower picture).

[0038] Figure 14 Photographs of the back of guinea pigs on the 4th day of the cutting oil application test in Example 8 (female in the upper picture, male in the middle picture, and young in the lower picture).

[0039] Figure 15 Photographs of the back of guinea pigs on the 8th day of the cutting oil application test in Example 8 (female in the upper picture, male in the middle picture, and young in the lower picture).

[0040] Figure 16 Photographs of the back of guinea pigs on the 12th day of the cutting oil application test in Example 8 (female in the upper picture, male in the middle picture, and young in the lower picture). Detailed implementation manners

[0041] To further understand the present invention, the present invention will be described below in conjunction with examples. However, the examples are only for further elaborating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0042] In the following examples, neopentyl polyol (NPE-3) was purchased from Shandong Ruijie New Materials Co., Ltd., and the physical and chemical properties of neopentyl polyol (NPE-3) are shown in Table 1. Diisooctyl sebacate was purchased from Shandong Ruijie New Materials Co., Ltd., and the physical and chemical properties of diisooctyl sebacate are shown in Table 2.

[0043] The aliphatic phosphate ester amine salt (T6450) is a mixture of a class of phosphate ester amine salts, and its structural general formula is as shown in Formula (1):

[0044]

[0045] In Formula (1), R is a C5-C8 aliphatic alkyl group, and NH2R` is a C12-C14 alkyl primary amine.

[0046] The physical and chemical properties of the aliphatic phosphate ester amine salt (T6450) are shown in Table 3, and its preparation process is as follows: C5-C8 fatty alcohol was put into a reaction kettle, and phosphorus pentoxide was added in batches under stirring at room temperature. After the feeding was completed, the reaction was carried out at 80-100 °C to obtain a mixture of phosphate esters. Then, C12-C14 alkyl primary amine (such as tertiary alkyl primary amine) was added in batches. After the feeding was completed, the reaction was carried out at 85-90 °C to generate a mixture of phosphate ester amine salts, which is the aliphatic phosphate ester amine salt (T6150). Its synthesis route is as follows:

[0047]

[0048] Octadecaneoxy thionano calcium borate (T365) was purchased from Qingdao Moser Lubricant Co., Ltd., and the physical and chemical properties of T365 are shown in Table 4. Octadecaneoxy azido calcium borate (T366) was purchased from Qingdao Moser Lubricant Co., Ltd., and the physical and chemical properties of T366 are shown in Table 5. The physical and chemical properties of sulfurized fatty acid esters are shown in Table 6.

[0049] Table 1 Physical and chemical properties of neopentyl polyol (NPE-3)

[0050]

[0051] Table 2 Physical and chemical properties of diisooctyl sebacate

[0052]

[0053] Table 3 Physical and chemical properties of aliphatic phosphate ester amine salt T6450

[0054]

[0055] Table 4 Physical and chemical properties of octadecaneoxy thionano calcium borate (T365)

[0056]

[0057] Table 5 Physicochemical properties of calcium octadecyloxyazaborate T366

[0058]

[0059] Table 6 Physicochemical properties of sulfurized fatty acid esters

[0060]

[0061] Examples 1-7 and Comparative Examples 1-3:

[0062] In the following examples and comparative examples, the environmentally friendly metal cutting oil is obtained by adding phosphoester amine salt extreme pressure additives, borate additives and sulfurized extreme pressure additives to a neopentyl polyol ester (NPE-3) base oil, stirring evenly, and heating at 85 °C for 50 min. Among them, the phosphoester amine salt extreme pressure additive is aliphatic phosphoester amine salt (T6450), the borate additive is calcium octadecyloxyazaborate (T366), and the sulfurized extreme pressure additive is sulfurized fatty acid ester and dialkyl pentasulfide (Rc2540). The addition amounts of each additive are shown in Table 7, where: the base oil is neopentyl polyol (NPE-3); the additives are T6450, T366, sulfurized fatty acid ester, Rc2540; the proportion of each additive in Table 7 refers to the weight ratio of the addition amount to the base oil).

[0063] Table 7 Composition and properties of cutting oil with NPE-3 as the base oil and T6450, T366, sulfurized fatty acid ester, Rc2540 as additives

[0064]

[0065] Perform performance tests on the cutting oils prepared in Examples 1-7, Examples 101, 102, 103 and Comparative Examples 1-3:

[0066] 1. Tribological performance test, and the test indicators are: the maximum non-seizure load Pb value and the low-load long-term wear test.

[0067] Use a four-ball tribotester provided by Shenyang Great Wall Lubricating Oil Manufacturing Co., Ltd., and the manufacturer is Jinan Yihua Tribology Testing Technology Co., Ltd. in Shandong. The model of the four-ball tribotester is MRS-10P, the maximum test force is 10 KN, the factory serial number is 1507, and the factory date is November 2015.

[0068] Test conditions for long-term wear: load F = 294 N, loading time T = 60 min;

[0069] The extreme pressure value Pb and long-term wear value D of the cutting oil products tested in each example and comparative example are shown in Table 7.

[0070] It can be seen that when the content of T6450 in samples E1 and E2 is low (0.04%, 0.12%) and the ratio of T6450 to T366 is also small, the Db value of the cutting oil is high. Although the addition amount and ratio of T6450 and T366 in sample E7 meet the standards, when the content of Rc2540 is low (0.03%), the Db value of the cutting oil is high. This fully demonstrates the importance of the synergistic effect of each component.

[0071] After optimizing the proportion of each component in the cutting oil, its load-carrying capacity (Pb) can reach more than 900 N, and the long-term wear value (Db) is less than 0.42 mm, as shown in Example 101, Example 102 and Example 103.

[0072] Analysis of the surface morphology of the specimen:

[0073] The SEM photograph and energy spectrum diagram of the wear scar of the steel ball in the four-ball test of Example 1 are shown in Figure 1-2. It can be clearly seen from the SEM photographs of the wear scar in Figure 1(a)-(b) that there is corrosion on the wear scar surface, indicating that the elements in the additive of the cutting oil have a slight corrosive effect on the metal surface of the steel ball. This is because the fatty cluster phosphate ester amine salt T6450 has a corrosive effect on the wear scar of the steel ball; at the same time, it can also be seen that the size and depth of the wear marks on the wear scar of the steel ball are small and shallow, and the wear marks are relatively evenly distributed, indicating that the addition of each additive to neopentyl polyol (NPE-3) plays a good anti-friction role.

[0074] Figure 2 (a)-(b) are the typical positions and corresponding energy spectrum diagrams on the surface of the wear scar of the steel ball. It can be seen in the figure that there are elements such as P and S on the wear scar of the steel ball, indicating that the additive plays a good anti-friction role during low-load long-term wear.

[0075] 2. Toxicity test: Detect the effect of the cutting oil in each example on the eyes of guinea pigs (eye drop test):

[0076] (1) Preparation before the experiment

[0077] A total of two guinea pigs were used in this experiment, one female (229.6 g) and one male (231.4 g), 2 months old. The selling unit is Liaoning Changsheng Biotechnology Co., Ltd.

[0078] The basis for selecting the sample oil is that the content of the additive in the cutting oil is moderate, which can well reflect the toxicity of the additive content.

[0079] The control oil sample is Borges Spanish Extra Virgin Olive Oil, which is an edible plant blended oil. The formula is 88 wt% sunflower oil and 12 wt% extra virgin olive oil of special grade.

[0080] Sample oil: The cutting oil prepared in Example 1.

[0081] (2) Eye drop test process and results

[0082] Drop the cutting oil prepared in Example 1 into the right eyes of guinea pigs, 3 - 5 ml each time. Drop the control oil sample, olive oil, into the left eyes of each guinea pig, 3 - 5 ml each time as a control.

[0083] The time intervals for eye drops are 3 min, 5 min, 10 min, 15 min, 30 min, 1 h, 2 h, 24 h, and 48 h. Take pictures before each eye drop. Figure 5 This is a photo of a guinea pig's eyes before the start of the test. Figure 6 This is the state of a guinea pig's eyes 3 min after eye drops. It can be seen that the eyes of the guinea pigs that have been dropped with the sample oil and olive oil are significantly squinted due to discomfort. However, it can be clearly seen that the degree of squinting of the left eyes of each group of guinea pigs is greater than that of the right eyes. It is speculated that this should be due to the high viscosity of olive oil and the non - toxicity of both the sample oil and olive oil, resulting in a greater degree of squinting in the left eyes. Figure 7 As can be seen in Figure 8 In

[0084] Conduct the tests of Examples 2 - 7 according to the above method, and the test results are the same as those of Example 1.

[0085] 3. Toxicity test: Detect the effect of the cutting oil in this example on the skin of guinea pigs (smearing test):

[0086] (1) Preparation before the experiment

[0087] A total of three guinea pigs are used in this test. The selling unit is Liaoning Changsheng Biotechnology Co., Ltd., including 1 adult female mouse, 1 adult male mouse, and 1 young mouse at 2 months old.

[0088] Use the product of Example 1 as the sample oil; the control oil sample is Borges Spanish Extra Virgin Olive Oil, which is an edible plant blended oil. The formula is 88 wt% sunflower oil and 12 wt% extra virgin olive oil of special grade.

[0089] (2) Smearing test process and result analysis

[0090] Remove the hair on the back of the guinea pig in a circular area with a diameter of 3 cm for smearing the oil sample. Smear the sample oil on the right rear back of the guinea pig, 2 - 3 ml each time. Smear olive oil on the left rear back of each guinea pig, 2 - 3 ml each time as a control.

[0091] The time of the smearing test is fourteen days, ensuring that it is smeared once a day. And take pictures on the fourth day, the eighth day, the twelfth day, and two days after the end of the test. Figures 9 - 12 For the smeared photos (the order of the photos from top to bottom is female, male, and young rats, and the left and right pictures are the left and right sides of the guinea pig's back respectively).

[0092] Figures 9 - 12 It can be clearly seen that during the whole smearing process, the skin of the guinea pigs remained intact all the time, and no adverse phenomena occurred. From this, it can be known that the sample oil, like olive oil, has no bad effects on the skin of guinea pigs.

[0093] The above smearing test was carried out on Examples 2 - 7, and the same effects as those of Example 1 were obtained.

[0094] Examples 8 - 16 and Comparative Examples 4 - 5:

[0095] In the following examples and comparative examples, the environmentally friendly metal cutting oil is obtained by adding phosphate ester amine salt extreme pressure additives, borate additives, and sulfurized extreme pressure additives to the base oil mixed with neopentyl polyol ester (NPE - 3) and diisooctyl sebacate, stirring evenly, and then heating at 85 °C for 50 min. Among them, the phosphate ester amine salt extreme pressure additive is aliphatic phosphate ester amine salt (T6450), the borate additive is T365, and the sulfurized extreme pressure additive is sulfurized fatty acid ester and dialkyl pentasulfide (Rc2540). The addition amounts of each additive are shown in Table 8, where: the volume mixing ratio of (NPE - 3) and diisooctyl sebacate in the base oil is 1:1; the additives are T6450, T365, sulfurized fatty acid ester, Rc2540; the proportion of each additive in Table 8 refers to the weight ratio of the addition amount to the base oil). Table 8 shows the composition and performance of the cutting oil with T6450, T365, sulfurized fatty acid ester, and Rc2540 as additives; test results: the long grinding conditions are 30 kg and 60 min

[0096] Table 8 Composition and performance test results of the cutting oil in the mixture of neopentyl polyol ester NPE - 3 (50%) and diisooctyl sebacate (50%) with T6450, T366, sulfurized fatty acid ester, and Rc2540 as additives

[0097]

[0098] Perform performance tests on the cutting oils prepared in Examples 8 - 16, Examples 104, 105, 106, and Comparative Examples 4 - 5:

[0099] 1. Tribological performance test, and the tested indicators are: the maximum non - seizure load Pb value and the low - load long - grinding test.

[0100] The four-ball friction and wear tester provided by Shenyang Great Wall Lubricating Oil Manufacturing Co., Ltd. was used, and the manufacturer is Jinan Yihua Tribology Testing Technology Co., Ltd. in Jinan, Shandong. The model of the four-ball tester is MRS--10P, the maximum test force is 10 kN, the factory serial number is 1507, and the factory date is November 2015.

[0101] Test conditions for low-load long-term wear: Load F = 294 N, loading time T = 60 min;

[0102] The measured extreme pressure value Pb and long-term wear value D are shown in Table 8.

[0103] It can be seen that when the content of T6450 in samples F1 and F2 is low (0.03%, 0.15%) and the ratio of T6450 to T365 is also small, the Db value of the cutting oil is high. This fully demonstrates the importance of the synergistic effect of each component.

[0104] After optimizing the proportion of each component in the cutting oil, its load-carrying capacity (Pb) can reach more than 1050 N, and the long-term wear value (Db) is less than 0.38 mm, as shown in Examples 104, 105, and 106.

[0105] Analysis of the surface morphology of the specimen:

[0106] The SEM photos and energy spectrum diagrams of the wear scars of the steel balls in the four-ball test of Example 8 are shown in Figures 3 - 4 , from Figure 3 (a)-(b) of the SEM photos of the wear scars, it can be clearly seen that there is corrosion on the surface of the wear scars, indicating that the elements in the additives of the cutting oil have a slight corrosive effect on the metal surface of the steel balls. This is because the fatty cluster phosphate ester amine salt T6450 has a corrosive effect on the wear scars of the steel balls; at the same time, it can also be seen that the size of the wear marks on the steel ball wear scars is small, the depth is shallow, and the wear marks are relatively evenly distributed, indicating that each additive added to the mixed base oil of neopentyl polyol (NPE-3) and diisooctyl sebacate has played a good anti-friction role.

[0107] Figure 4 (a)-(b) are the typical positions and corresponding energy spectrum diagrams on the surface of the steel ball wear scars. It can be seen in the figure that there are elements such as P and S on the top of the steel ball wear scars, indicating that the additives play a good anti-friction role during low-load long-term wear.

[0108] 2. Toxicity test: Detect the influence of the cutting oil in each example on the eyes of guinea pigs (eye drop test):

[0109] A total of three guinea pigs were used in this test, one female (286 g), one male (290 g), and two months old. One young rat (224). The sample oil is the cutting oil prepared in Example 8, and the other processes are the same as those in the eye drop experiment of the sample oil in Example 1.

[0110] The change process of the guinea pig's eyes during eye drops was basically the same as that of the cutting oil in Example 1. Figure 13 For the cutting oil in Example 8, after 24 hours of the guinea pig eye drop test, it can be seen that there is no obvious difference between the right eye with the sample oil dropped and the left eye with olive oil dropped and the eyes of guinea pigs in the normal state.

[0111] The above eye drop tests were carried out on Examples 9 - 14, and the same effects as those in Example 8 were obtained.

[0112] 3. Toxicity test: Detect the effect of the cutting oil in this example on the skin of guinea pigs (smearing test):

[0113] (1) Preparation before the test

[0114] A total of three guinea pigs were used in this test, including 1 adult female rat (264 g) at 2 months old, 1 adult male rat (275 g), and 1 young rat (234 g).

[0115] The cutting oil in Example 8 was used as the sample oil; the control oil sample was Borges Spanish extra virgin olive oil, which is an edible vegetable blended oil. The formula is 88 wt% sunflower oil and 12 wt% extra virgin olive oil of special grade.

[0116] (2) Process and result analysis of the smearing test

[0117] The process of the smearing test was the same as that of the cutting oil in Example 1. Figures 14 - 16 Shown are the smearing photos (from top to bottom in the photo order are female, male, and young rat, and the left and right pictures are the left and right sides of the guinea pig's back respectively).

[0118] Figures 14 - 16 It can be clearly seen that during the whole smearing process, the skin of the guinea pigs remained intact and no adverse phenomena occurred. From this, it can be known that the sample oil, like olive oil, has no bad effects on the skin of guinea pigs.

[0119] The above smearing tests were carried out on Examples 9 - 14, and the same effects as those in Example 8 were obtained.

[0120] The above eye drop test refers to the eye conjunctiva irritation test, and its reaction evaluation criteria are shown in Table 9.

[0121] The smearing test is a skin irritation test, and the skin irritation reaction evaluation criteria are shown in Table 10.

[0122] Table 9 Reaction evaluation criteria for eye irritation test

[0123]

[0124] Table 10 Skin irritation reaction evaluation criteria

[0125]

[0126]

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An environmentally friendly metal cutting oil based on neopentyl polyol ester, characterized in that: The cutting oil is composed of base oil and additives, wherein: the base oil is a mixture of neopentyl polyol ester (NPE-3) and diisooctyl sebacate; the additives include phosphate amine salt extreme pressure additives, borate series additives, and sulfurized extreme pressure additives.

2. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 1, characterized in that: The phosphate amine salt extreme pressure additive is a fatty cluster phosphate amine salt (T6450); the borate series additive is octadecyloxy calcium nitrogen borate (T366) or octadecyloxy calcium sulfide nanoborate (T365); the sulfurized extreme pressure additive is sulfurized fatty acid ester and dialkyl pentasulfide (Rc2540).

3. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 1 or 2, characterized in that: The amount of the phosphate amine salt extreme pressure additive added is 0.15-0.85% (preferably 0.20-0.80%) of the base oil weight; the amount of the borate additive added is 0.04-1.8% of the base oil weight; The ratio of the amount of the phosphate amine salt extreme pressure additive added to the amount of the borate additive added is greater than 0.3; The amount of the sulfurized fatty acid ester added is 0.03-1.2% of the weight of the base oil, and the amount of the dialkyl pentasulfide (Rc2540) added is 0.12-0.80% of the weight of the base oil.

4. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 1, characterized in that: In the base oil, the volume proportion of neopentyl polyol ester (NPE-3) is 40-100%.

5. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 3 or 4, characterized in that: When the base oil is neopentyl polyol ester, the preferred formula I of the cutting oil is: the addition amount of the phosphate amine salt extreme pressure additive is 0.40-0.85wt.% of the weight of the base oil, the addition amount of the borate additive is 0.05-0.35wt.% of the weight of the base oil; the addition amount of the sulfurized fatty acid ester is 0.03-0.75wt.% of the weight of the base oil, and the addition amount of the dialkyl pentasulfide (Rc2540) is 0.25-0.75wt.% of the weight of the base oil; the load-bearing capacity (Pb) of the cutting oil of formula I is greater than 900N, and the long wear value (Db) is less than 0.42mm.

6. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 3 or 4, characterized in that: When the base oil is a mixture of neopentyl polyol ester and diisooctyl sebacate in a volume ratio of 1:1, the preferred formula II of the cutting oil is: the addition amounts (wt.%) of the phosphate amine salt extreme pressure additive, borate additive, sulfurized fatty acid ester and dialkyl pentasulfide (Rc2540) in the base oil are 0.02-0.10%, 0.04-0.25%, 0.03-0.75%, 0.03-0.75%, respectively, Alternatively, the addition amounts (wt.%) of the phosphate amine salt extreme pressure additives, borate additives, sulfurized fatty acid esters and dialkyl pentasulfide (Rc2540) in the base oil are 0.35-0.5%, 1.20-1.60%, 0.60-0.80% and 0.65-0.85%, respectively. The load-bearing capacity (Pb) of the cutting oil of formula II is greater than 1050N, and the long wear value (Db) is less than 0.38mm.

7. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 2, characterized in that: The fatty cluster phosphate amine salt (T6450) is a mixture of phosphate amine salts, and its general structural formula is as follows: In formula (1), R is a C5-C8 aliphatic alkyl group, and NH2R' is a C12-C14 alkyl primary amine.

8. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 2, characterized in that: The octadecyloxy calcium nitrogen borate (T366) and the octadecyloxy calcium sulfide borate (T365) were both purchased from Qingdao Mosel Lubricant Co., Ltd.

9. The environmentally friendly metal cutting oil based on neopentyl polyol ester according to claim 3, characterized in that: The preparation process of the environmentally friendly cutting fluid is as follows: adding phosphate amine salt extreme pressure additives, borate additives and sulfurized extreme pressure additives to the base oil in proportion, stirring evenly, and heating at 75-100° C. for 30-60 minutes to obtain the environmentally friendly metal cutting oil.

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