Dewaxing aid for solvent dewaxing.

Abstract

This dewaxing aid includes an ethylene-α-olefin copolymer (A) in which the molar ratio (a) / (b) of (a) ethylene and (b) an α-olefin having 3-12 carbon atoms is 93 / 7 to 75 / 25 inclusive and the weight average molecular weight is 10,000 to 500,000 inclusive.　The present invention makes it possible to provide a dewaxing aid that is excellent in improving filterability.

Description

[Technical field]

[0001] The present invention relates to a dewaxing aid for solvent dewaxing, and more particularly to an aid for improving filterability when removing wax from mineral oils and the like by filtration. [Background technology]

[0002] Generally, lubricating base oils used in lubricating oil compositions are produced by distilling crude oil, followed by various refining processes, so as to have desired physical properties. In many lubricating base oil production methods, the unrefined distillate oils produced by distillation contain a large amount of paraffin wax (hereinafter also simply referred to as "wax content"), and therefore have a high pour point. In order to obtain a lubricating base oil with a low pour point, a dewaxing process is carried out to remove the wax content from the distillate oil.

[0003] Typically, dewaxing is carried out using a solvent dewaxing device by adding a solvent such as methyl ethyl ketone to a dewaxed feedstock, which is a distillate oil containing wax, to produce a mixed oil, which is then cooled to a temperature below the desired pour point to precipitate the wax. The mixed oil from which the wax has been precipitated is then passed through a filter to separate the wax and the dewaxed oil.

[0004] In recent years, with the increase in demand for lubricating base oils, there is a demand for an increase in the throughput in dewaxing treatment. However, even if the supply amount of dewaxing raw material is increased, there is a problem that the throughput cannot be increased sufficiently because the filtration rate in the filter is slow. In order to improve the filterability in the dewaxing treatment, various polymers may be added as dewaxing aids. The dewaxing aids improve the filterability by controlling the crystal structure and aggregation form of the precipitated wax. For example, Patent Document 1 discloses a mixture of an olefin-vinyl acetate copolymer and a polyalkyl (meth)acrylate, Patent Document 2 discloses a condensate of chlorinated paraffin and biphenyl, and Patent Document 3 discloses a dewaxing aid consisting of a polyalkyl (meth)acrylate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 54-011104 [Patent Document 2] Japanese Patent Application Publication No. 04-077598 [Patent Document 3] JP 2004-231928 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the dewaxing aids available to date have been insufficient in improving filterability, and there is a demand for ones with a stronger improving effect. An object of the present invention is to provide a dewaxing aid that is excellent in improving filterability. [Means for solving the problem]

[0007] As a result of intensive research conducted by the present inventors to solve the above problems, they have found that a dewaxing aid containing a specific ethylene-α-olefin copolymer obtained from ethylene and a specific α-olefin is excellent in improving filterability. That is, the present invention provides the following [1] and [2]. [1] A dewaxing aid comprising an ethylene-α-olefin copolymer (A) having a molar ratio of (a) ethylene and (b) an α-olefin having 3 to 12 carbon atoms [(a) / (b)] of 93 / 7 to 75 / 25 and a weight average molecular weight of 10,000 to 500,000. [2] A dewaxing aid comprising an ethylene-ethyl acrylate copolymer (B) having a molar ratio of (c) ethylene and (d) ethyl acrylate [(c) / (d)] of 98 / 2 to 80 / 20 and a weight average molecular weight of 50,000 to 1,000,000, and the copolymer (A) according to [1] in a ratio of (A) / (B) = 95 / 5 to 70 / 30 (mass ratio). Effect of the Invention

[0008] The dewaxing aid of the present invention is excellent in improving the filterability when wax is removed by filtration from mineral oils and the like using a solvent. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The dewaxing aid of the present invention will be described below. In this specification, a numerical range specified using the symbol "~" includes both the upper and lower limits of the range. For example, "2~5" means 2 or more and 5 or less.

[0010] The present invention relates to a dewaxing aid characterized by containing an ethylene-α-olefin copolymer (A) having a molar ratio of (a) ethylene and (b) an α-olefin having 3 to 12 carbon atoms [(a) / (b)] of 93 / 7 to 75 / 25 and a weight average molecular weight of 10,000 to 500,000.

[0011] The ethylene-α-olefin copolymer (A) in the present invention is a copolymer obtained by polymerizing ethylene and an α-olefin having 3 to 12 carbon atoms. The raw material for the copolymer in the present invention is an α-olefin having 3 to 12 carbon atoms. From the viewpoint of filterability, an α-olefin having 4 to 8 carbon atoms is preferable, and an α-olefin having 4 carbon atoms is more preferable. Examples of the α-olefin having 3 to 12 carbon atoms include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene.

[0012] The weight average molecular weight of the ethylene-α-olefin copolymer (A) in the present invention is 10,000 to 500,000. The weight average molecular weight is preferably 30,000 to 300,000, more preferably 40,000 to 200,000, and even more preferably 50,000 to 150,000. If the weight average molecular weight is less than 10,000, the filterability may not be improved. On the other hand, if it exceeds 500,000, the viscosity may be high and the handleability may be deteriorated. The weight average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC) under the following conditions and calculated in terms of polystyrene.

[0013] <Measurement conditions> Equipment: Tosoh Corporation, HLC-8220 Column: Shodex, LF-804 Standard material: polystyrene Eluent: THF (tetrahydrofuran) ·Flow rate: 1.0ml / min ·Temperature: 40℃ Detector: RI (Differential Refractive Index Detector)

[0014] In the ethylene-α-olefin copolymer (A) of the present invention, the molar ratio of (a) ethylene and (b) α-olefin having 3 to 12 carbon atoms is (a) / (b)=93 / 7 to 75 / 25. The molar ratio of (a) ethylene and (b) α-olefin having 3 to 12 carbon atoms means the molar ratio of the structural unit derived from ethylene present in the ethylene-α-olefin copolymer to the structural unit derived from α-olefin having 3 to 12 carbon atoms. The molar ratio [(a) / (b)] of (a) ethylene and (b) α-olefin having 3 to 12 carbon atoms is preferably 92 / 8 to 80 / 20, more preferably 90 / 10 to 83 / 17, and even more preferably 90 / 10 to 85 / 15. If the molar ratio of (a) ethylene and (b) α-olefin having 3 to 12 carbon atoms is outside the range of 93 / 7 to 75 / 25, there is a risk that the filterability will not be improved.

[0015] In the present invention, the "molar ratio" is determined by dissolving an ethylene-α-olefin copolymer in deuterated toluene. 1 The molar ratio of ethylene to α-olefin can be calculated by measuring HNMR. Specifically, the molar ratio of ethylene to α-olefin can be calculated from the ratio of the integral values ​​of the peak (0.40 to 0.60 ppm) derived from the terminal methyl of α-olefin to the peak (0.85 to 1.05 ppm) derived from ethylene and the alkyl group other than the terminal methyl of α-olefin.

[0016] <Measurement conditions> Equipment: JNM-AL, manufactured by JEOL Ltd. Frequency: 400MHz Solvent: deuterated toluene ·Concentration: 10g / L ·Temperature: 60℃

[0017] The ethylene-α-olefin copolymer (A) contained in the dewaxing aid of the present invention is preferably a combination of two or more ethylene-α-olefin copolymers having different molar ratios [(a) / (b)]. More specifically, the ethylene-α-olefin copolymers (A) having different molar ratios [(a) / (b)] are preferably used in combination. H ), and ethylene-α-olefin copolymer (A L It is more preferable to use two of the above in combination. H ) and (A L There is no particular restriction on the mixing ratio of (A H ) / (A L ) is preferably in a mass ratio of 90 / 10 to 10 / 90. (A H ) / (A L The mass ratio of (A) is more preferably 75 / 25 to 25 / 75, further preferably 60 / 40 to 40 / 60, and particularly preferably 50 / 50. If it is in the range of 90 / 10 to 10 / 90, the effect of improving the filterability can be further improved. H ) and (A L If you use (A) in combination with H ), (A L ) is preferably used.

[0018] (AH ): an ethylene-α-olefin copolymer having a molar ratio [(a) / (b)] of (a) ethylene and (b) an α-olefin having 3 to 12 carbon atoms of 93 / 7 to 87 / 13 and a weight average molecular weight of 10,000 to 500,000.

[0019] (A L ): an ethylene-α-olefin copolymer in which the molar ratio [(a) / (b)] of (a) ethylene and (b) an α-olefin having 3 to 12 carbon atoms is less than 87 / 13 and 75 / 25 or more, and the weight average molecular weight is 10,000 to 500,000.

[0020] In addition, from the viewpoint of filterability (A H ) and (A L The α-olefin contents of the copolymers preferably differ by 1 mol % or more, and more preferably by 2 mol % or more.

[0021] The ethylene-α-olefin copolymer (A) of the present invention can further enhance the effect of improving the filterability by using it in combination with a specific ethylene-ethyl acrylate. More specifically, the ethylene-ethyl acrylate copolymer (B) having a molar ratio [(c) / (d)] of (c) ethylene and (d) ethyl acrylate of 98 / 2 to 80 / 20 and a weight average molecular weight of 50,000 to 1,000,000 can be used in combination at a ratio of (A) / (B)=95 / 5 to 70 / 30 (mass ratio) to further enhance the effect of improving the filterability. The mass ratio of (A) / (B) is more preferably 90 / 10 to 75 / 25, and further preferably 85 / 15 to 75 / 25. By using them in combination at a ratio within this range, the effect of improving filterability can be further enhanced.

[0022] The weight average molecular weight of the ethylene-ethyl acrylate copolymer (B) is 50,000 to 1,000,000. The weight average molecular weight is preferably 60,000 to 800,000, more preferably 70,000 to 600,000, and even more preferably 75,000 to 500,000. By using an ethylene-ethyl acrylate copolymer having a weight average molecular weight in this range in combination, the effect of improving filterability can be further enhanced.

[0023] The ethylene-ethyl acrylate copolymer (B) has a molar ratio [(c) / (d)] of (c) ethylene and (d) ethyl acrylate of 98 / 2 to 80 / 20. The molar ratio of (c) ethylene and (d) ethyl acrylate means the molar ratio of the ethylene-derived structural unit and the ethyl acrylate-derived structural unit present in the ethylene-ethyl acrylate copolymer. The molar ratio [(c) / (d)] of (c) ethylene and (d) ethyl acrylate is preferably 98 / 2 to 82 / 18, more preferably 96 / 4 to 84 / 16, and even more preferably 92 / 8 to 86 / 14. By using an ethylene-ethyl acrylate copolymer having a molar ratio [(c) / (d)] in this range in combination, the effect of improving the filterability can be further enhanced. The "molar ratio" of (c) ethylene and (d) ethyl acrylate was determined by dissolving an ethylene-ethyl acrylate copolymer in deuterated chloroform. 1 The molar ratio of ethylene and ethyl acrylate can be calculated by measuring HNMR. Specifically, the molar ratio of ethylene and ethyl acrylate can be calculated from the ratio of the integral values ​​of the peak (4.00 to 4.20 ppm) derived from the alkyl of -COOCH2- of ethyl acrylate, the peak derived from ethylene, and the peak (0.70 to 1.70 ppm) derived from the alkyl other than the alkyl of -COOCH2- of ethyl acrylate.

[0024] From the viewpoint of workability, the dewaxing aid may be used after diluting with a diluent. Examples of the diluent include mineral oils derived from crude oil as a starting material and aromatic solvents, such as kerosene base components, light oil base components, toluene, and xylene.

[0025] When the dewaxing aid is diluted with a diluent, the amount of diluent blended is, for example, 0.05 to 20 parts by mass, preferably 1 to 15 parts by mass, and more preferably 2 to 10 parts by mass, per 1 part by mass of the dewaxing aid.

[0026] The dewaxing aid of the present invention may contain other optional components as necessary. Examples of the optional components include polyalkyl (meth)acrylates, alkylated aromatic compounds, etc. The dewaxing aid may be adjusted by appropriately mixing these optional components with the ethylene-α-olefin copolymer as desired in an amount within a range that does not impede the object of the present invention. As described above, the dewaxing aid of the present invention may be used after diluting with a diluent. The diluent is a component that is added to the dewaxing aid and is a component other than the components that may be contained in the dewaxing aid.

[0027] The dewaxing aid of the present invention can be suitably used for filtering and removing wax from mineral oils, etc. Specifically, the dewaxing aid of the present invention can be suitably used by adding it to wax-containing hydrocarbon oils, such as petroleum distillate oils, for filtering and removing wax.

[0028] When the dewaxing aid of the present invention is added to a wax-containing hydrocarbon oil, the amount added is not particularly limited, but the amount of ethylene-α-olefin copolymer contained in the dewaxing aid is, for example, 10 to 3,000 ppm, preferably 50 to 500 ppm, and more preferably 200 to 500 ppm relative to the wax-containing hydrocarbon oil. If the amount added is too small, sufficient effect cannot be obtained, while adding more than necessary may not improve the effect and may even reduce it.

[0029] The dewaxing aid is preferably added to a mixed oil obtained by mixing a wax-containing hydrocarbon oil with a solvent. Examples of the solvent include methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, butane, and pentane, and two or more types of solvents may be mixed. The mass ratio of the wax-containing hydrocarbon oil to the solvent (wax-containing hydrocarbon oil / solvent) is not particularly limited, but is preferably 50 / 50 to 5 / 95, and more preferably 30 / 70 to 10 / 90. After the dewaxing aid is added to the mixed oil, the mixed oil is heated to dissolve uniformly, and then cooled to precipitate the wax, and the precipitated wax is removed by filtration. The heating temperature when heating is preferably 40 to 90°C, and the cooling temperature when cooling is preferably -40 to -20°C. The dewaxing aid of the present invention has excellent filterability for wax, and therefore makes it possible to efficiently remove wax.

[0030] Examples of wax-containing hydrocarbon oils include petroleum distillate oils, and examples of the petroleum distillate oils used in the present invention include residual oils accumulated at the bottom of a distillation tower obtained by atmospheric or reduced pressure distillation of crude oils such as paraffinic crude oil, intermediate base crude oil, naphthenic crude oil, etc. The residual oils have a high weight average molecular weight and are used as raw materials for bright stocks obtained by subjecting the crude oils to dewaxing treatment and various refining treatments.

[0031] The weight average molecular weight of the petroleum distillate oil used in one embodiment of the present invention is 900 or more, preferably 1000 or more, more preferably 1100 or more, even more preferably 1200 or more, and still more preferably 1300 or more, and is usually 3000 or less.

[0032] The petroleum distillate oil used in one embodiment of the present invention preferably has a kinematic viscosity at 100° C. of 20.0 to 60.0 mmHg. 2 / s, more preferably 23.0 to 55.0 mm 2 / s, more preferably 25.0 to 50.0 mm 2 In this specification, the kinematic viscosity refers to a value measured and calculated in accordance with JIS K2283:2000. The flash point of the petroleum distillate oil used in one embodiment of the present invention is preferably 300° C. or higher, more preferably 310° C. or higher, and even more preferably 320° C. or higher, and is usually 350° C. or lower. In this specification, the flash point refers to a value measured by the Cleveland open cup (COC) method in accordance with JIS K2265-4. The pour point of the petroleum distillate oil used in one embodiment of the present invention is usually 40 to 50° C. In this specification, the pour point refers to a value measured in accordance with JIS K2269:1987. EXAMPLES

[0033] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0034] [Ethylene-α-olefin copolymer (A)] (Synthesis Example 1) A mixture of ethylene and 1-butene was continuously fed to a stirred autoclave type continuous reactor so that the ratio of 1-butene was 35 mol % (the total amount of ethylene and 1-butene was 100 mol %), and a polymerization reaction was carried out in the presence of a metallocene catalyst at a pressure of 92 MPa and a temperature of 194°C to obtain Polymer A. H The metallocene catalyst used was a catalyst consisting of dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)hafnium dimethyl / tri(pentafluorophenyl)boron = 1 / 2 (molar ratio). In addition, by changing the ratio of 1-butene in Synthesis Example 1 or by appropriately changing 1-butene to other α-olefins and carrying out the operations similar to Synthesis Example 1, polymer A in Table 1 can be obtained. H -2 and A H -3, Polymer A in Table 2 L -1 and A L Polymers A'-1 and A'-2 in Table 3 were obtained.

[0035] [Ethylene-ethyl acrylate copolymer (B)] (Synthesis Example 2) An organic peroxide and a mixture of ethylene and ethyl acrylate were continuously fed to a stirred autoclave type continuous reactor so that the ratio of ethyl acrylate was 3 mol % (the total amount of ethylene and ethyl acrylate being 100 mol %), and a polymerization reaction was carried out at a pressure of 130 MPa and a temperature of 195°C to obtain polymer B1 in Table 4. t-Butylperoxy 2-ethylhexanoate was used as the organic peroxide. Polymer B2 in Table 4 was obtained by changing the ratio of ethyl acrylate in Synthesis Example 2 and carrying out the same procedure as in Synthesis Example 2.

[0036] (Synthesis Example 3) A reactor equipped with a thermometer, nitrogen inlet tube, stirrer and heater was charged with toluene / alkyl methacrylate = 12 / 88 (mass ratio), and polymerization reaction was carried out under nitrogen atmosphere at 80 ° C while gradually adding an azo-based initiator. After the reaction, toluene was removed under reduced pressure at 120 ° C to obtain polymer C with a weight average molecular weight of 190,000. As the alkyl methacrylate, C12-22 alkyl methacrylate (C12 / C14 / C16 / C18 / C20 / C22 = 4 / 8 / 4 / 35 / 15 / 35, mass ratio) was used, and as the azo-based initiator, 2,2-azobis-2,4-dimethylvaleronitrile was used. Note that "C12" indicates that the number of carbon atoms in the alkyl group is 12.

[0037] [Table 1]

[0038] [Table 2]

[0039] [Table 3]

[0040] [Table 4]

[0041] (Preparation Example 1) Polymer A H -1, Polymer A L The mixture was mixed at 100° C. with Polymer B1 in a ratio of 40:40:20 (mass ratio) to prepare Dewaxing Aid D1. In addition, dewaxing aids D2 and D3 in Table 5 were prepared by changing the polymer in Preparation Example 1 and carrying out the operations similar to Preparation Example 1. The polymers shown in Table 5 were designated as dewaxing aids D4 to D12.

[0042] [Table 5]

[0043] <Example 1> Dewaxing aid D1 and toluene (diluent) were charged in a mass ratio of dewaxing aid D1 / toluene (diluent) = 2 / 8, and mixed with stirring at a temperature of 100°C to prepare a diluted solution E1 of the dewaxing aid. 0.23 g (300 ppm as polymer) of the dilution solution E1 of the dewaxing aid prepared separately was added to 150 g of mixed oil prepared with wax-containing hydrocarbon oil / methyl ethyl ketone / toluene = 1 / 2 / 2 (mass ratio), and heated to a temperature of 70 ° C. to dissolve uniformly. The mixed oil was placed in a test container and cooled to a temperature of -30 ° C. at a rate of 2 ° C. / min while stirring. After cooling, the slurry with the wax precipitated was placed in a suction filter and subjected to vacuum filtration at a temperature of -30 ° C. and 200 mmHg. The time when the slurry was placed in the filter was set to 0 seconds, and the time when 100 mL of the filtrate flowed was measured. The time when 100 mL flowed was set to the filtration time, and the shorter the filtration time, the better the filterability. The results are shown in Table 6. The evaluation was made as follows: A = filtration time less than 350 seconds, B = filtration time 350 seconds or more and less than 600 seconds, C = filtration time 600 seconds or more. In addition, the filter media used in this test had an airflow rate of approximately 100 cm 3 / cm 2sec, and "hydrocarbon oil" is a residual oil containing wax obtained by hydrotreating the residual oil remaining at the bottom of the column when crude oil is distilled under reduced pressure. The structure and physical properties of the residual oil are as follows: weight average molecular weight (Mw) = 1440, kinetic viscosity at 100°C = 30 mm 2 / s, pour point = 45℃, flash point = 325℃.

[0044] <Examples 2 to 8 and Comparative Examples 1 to 4> The filtration time was measured in the same manner as in Example 1, except that the dewaxing aid used in Example 1 was changed as shown in Table 6. The results are shown in Table 6.

[0045] <Example 9> The same procedure as in Example 1 was carried out, except that the amount of the diluted solution E1 of the dewaxing aid added was changed to 0.11 g (150 ppm as polymer). The results are shown in Table 7.

[0046] <Examples 10 to 12 and Comparative Examples 5 to 6> The filtration time was measured in the same manner as in Example 9, except that the dewaxing aid used in Example 9 was changed as shown in Table 7. The results are shown in Table 7.

[0047] [Table 6]

[0048] [Table 7]

[0049] From the results of Tables 6 and 7, Examples 1 to 12, which used the dewaxing aid of the present invention, had shorter filtration times than Comparative Examples 1 to 6. Therefore, it was found that the dewaxing aid of the present invention has significantly improved filterability compared to the dewaxing aids of the Comparative Examples. [Industrial Applicability]

[0050] According to the present invention, a dewaxing aid that is excellent in improving filterability can be provided.

Claims

1. A dewaxing aid for solvent dewaxing, comprising an ethylene-α-olefin copolymer (A) having a molar ratio of (a) ethylene and (b) an α-olefin having 3 to 12 carbon atoms [(a) / (b)] of 93 / 7 to 75 / 25 and a weight average molecular weight of 10,000 to 500,000.

2. A dewaxing aid for solvent dewaxing, comprising: (B) an ethylene-ethyl acrylate copolymer having a molar ratio of (c) ethylene and (d) ethyl acrylate [(c) / (d)] of 98 / 2 to 80 / 20 and a weight average molecular weight of 50,000 to 1,000,000; and (A) according to claim 1 in a ratio of (A) / (B) = 95 / 5 to 70 / 30 (mass ratio).

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