Additive and fuel oil composition

Abstract

To provide a new additive that improves low-temperature fluidity of a specific fuel oil.SOLUTION: An additive for a specific fuel oil comprising a provided ethylene-vinyl acetate copolymer of the present invention has a weight average molecular weight Mw of 50,000 to 250,000, has a vinyl acetate content of 25 to 40 mass% in constituent monomers, and has a branching degree of 0.90 to 4.0% measured by 13C-NMR.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an additive capable of improving fluidity at low temperatures by lowering the pour point of fuel oil with a reduced sulfur content.

Background Art

[0002] In fuel oils used in internal combustion engines, ships, aircraft, external combustion engines, etc., when exposed to a low-temperature environment in winter or cold regions, part or all of the fuel oil solidifies or precipitates, causing problems such as clogging of pipes and filters. To solve this problem, additives such as pour point depressants and fluidity improvers are usually blended into fuel oils.

[0003]

[0004] For example, Patent Document 1 describes a light oil composition obtained by adding a fraction and a vinyl acetate-based low-temperature fluidity improver to light oil with an adjusted distillation range. Patent Document 2 describes a copolymer composed of 50 to 94% by weight of ethylene, 3 to 30% by weight of vinyl esters of monocarboxylic acids having 2 to 6 carbon atoms, 3 to 20% by weight of aminoalkyl acrylates, and 0 to 10% by weight of other monomers as a fluidity improver for middle distillates of mineral oil. Patent Document 3 describes a light oil composition having a sulfur content of 0.05% by mass or less and containing at least one selected from ethylene-vinyl acetate copolymers and the like. Patent Document 4 describes a mixture of aviation fuel and a compound capable of lowering the freezing point of aviation fuel such as ethylene-vinyl acetate copolymer.​There is a need for a new additive that can exhibit practical effects even for fuel oils with a sulfur content of 0.53 mass% or less.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] Accordingly, an object of the present invention is to provide an additive that can improve fluidity at low temperatures by lowering the pour point even for specific fuel oils for which existing additives do not provide effective results.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventors have found that an additive composed of a specific ethylene-vinyl acetate copolymer can lower the pour point and improve fluidity at low temperatures even for fuel oils having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less, for which existing additives do not provide effective results, and have completed the present invention. That is, the present invention relates to an ethylene-vinyl acetate copolymer having a weight average molecular weight Mw of 50,000 to 250,000, a vinyl acetate content in the constituent monomers of 25 to 40 mass%, and a branching degree measured by 13C-NMR of 0.90 to 4.0%, and having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s, and is an additive for fuel oils having a sulfur content of 0.53 mass% or less.

Advantages of the Invention

[0008] By using the additive for fuel oil of the present invention, the pour point of fuel oil with a low sulfur content can be lowered, and the fluidity at low temperatures can be improved.

Embodiments for Carrying Out the Invention

[0009] The ethylene-vinyl acetate copolymer used in the present invention contains ethylene and vinyl acetate as constituent monomers, and is an ethylene-vinyl acetate copolymer in which the content of vinyl acetate in the constituent monomers is 25 to 40% by mass. At this time, it may contain compounds other than ethylene and vinyl acetate as constituent monomers. For example, olefin compounds having 3 to 22 carbon atoms, vinyl ester compounds having an alkyl group having 2 to 40 carbon atoms in the molecule, vinyl ether compounds having an alkyl group having 2 to 40 carbon atoms in the molecule, acrylate compounds having an alkyl group having 1 to 40 carbon atoms in the molecule, methacrylate compounds having an alkyl group having 1 to 40 carbon atoms in the molecule, styrene compounds, and derivatives thereof, etc. can be mentioned. In the present invention, from the viewpoint of effectively lowering the pour point of fuel oil having a kinematic viscosity at 50°C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53% by mass or less, the total amount of ethylene and vinyl acetate with respect to the total amount of constituent monomers constituting the ethylene-vinyl acetate copolymer is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and even more preferably 100% by mass (the constituent monomers consist only of ethylene and vinyl acetate). Also, the kinematic viscosity at 50°C is 3.0 to 450 mm 2From the perspective of further lowering the pour point of a fuel oil having a sulfur content of 0.53 mass% or less, the content of vinyl acetate relative to the total amount of constituent monomers constituting the ethylene-vinyl acetate copolymer is preferably 26 to 36 mass%, more preferably 27 to 34 mass%, and even more preferably 28 to 32 mass%. In the present invention, the content of vinyl acetate in the ethylene-vinyl acetate copolymer is measured by the method described in JIS K 7192 (1999).

[0010] The ethylene-vinyl acetate copolymer used in the present invention is an ethylene-vinyl acetate copolymer having a weight average molecular weight Mw of 50,000 to 250,000. In the present invention, by using an ethylene-vinyl acetate copolymer having a weight average molecular weight within this range, for a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less, the pour point can be lowered and the fluidity at low temperatures can be improved. For a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 From the perspective of further lowering the pour point of a fuel oil having a sulfur content of 0.53 mass% or less, the weight average molecular weight Mw of the ethylene-vinyl acetate copolymer is preferably 60,000 to 220,000, more preferably 80,000 to 200,000, and even more preferably 100,000 to 180,000. In the present invention, the weight average molecular weight Mw of the ethylene-vinyl acetate copolymer is measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and is the weight average molecular weight calculated in terms of polystyrene.

[0011] The detailed measurement conditions for the weight average molecular weight Mw of the ethylene-vinyl acetate copolymer are as follows. · Weight average molecular weight measurement conditions GPC apparatus: GL-7400 series (manufactured by GL Sciences Inc.) Columns: Two GPC LF-404 (particle size 6 μm, 4.6 × 250 mm), GPC KF-402.5HQ (particle size 3 μm, 4.6 × 250 mm), GPC KF-401HQ (particle size 3 μm, 4.6 × 250 mm), GPC LF-G (particle size 6 μm, 4.6 × 10 mm) (all manufactured by Showa Denko K.K.) are connected in series and used Detector: GL-7454 Flow rate: 0.3 ml / min Sample concentration: 20 mg / 10 ml (THF solution) Injection volume: 5 μl Column temperature: 40 °C Standard sample: Polystyrene

[0012] The number average molecular weight Mn of the ethylene-vinyl acetate copolymer used in the present invention is not particularly limited. However, from the viewpoint of further lowering the pour point of a fuel oil having a kinematic viscosity of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less, the number average molecular weight Mn is preferably 15,000 to 80,000, more preferably 25,000 to 60,000, and even more preferably 30,000 to 60,000. In the present invention, the number average molecular weight Mn of the ethylene-vinyl acetate copolymer is measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent, and is the number average molecular weight calculated in terms of polystyrene.

[0013] The detailed measurement conditions for the number average molecular weight Mw of the ethylene-vinyl acetate copolymer are as follows. ·Number average molecular weight measurement conditions GPC apparatus: GL-7400 series (manufactured by GL Sciences Inc.) Columns: Two GPC LF-404 (particle size 6 μm, 4.6 × 250 mm), GPC KF-402.5HQ (particle size 3 μm, 4.6 × 250 mm), GPC KF-401HQ (particle size 3 μm, 4.6 × 250 mm), GPC LF-G (particle size 6 μm, 4.6 × 10 mm) (all manufactured by Showa Denko K.K.) are connected in series and used Detector: GL-7454 Flow rate: 0.3 ml / min Sample concentration: 20 mg / 10 ml (THF solution) Injection volume: 5 μl Column temperature: 40 °C Standard sample: Polystyrene

[0014] The [weight average molecular weight Mw / number average molecular weight Mn] of the ethylene-vinyl acetate copolymer used in the present invention is not particularly limited, but from the viewpoint of further lowering the pour point of a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less, it is preferably 1.5 to 4.0, more preferably 2.0 to 3.8, and even more preferably 2.5 to 3.6. In the present invention, the [weight average molecular weight Mw / number average molecular weight Mn] of the ethylene-vinyl acetate copolymer is calculated using the values of the weight average molecular weight Mw and the number average molecular weight Mn measured by the method described above.

[0015] The ethylene-vinyl acetate copolymer used in the present invention is an ethylene-vinyl acetate copolymer having a branching degree of 0.90 to 4.0% measured by 13C-NMR. The branching degree measured by 13C-NMR is an index correlated with the abundance ratio of the linear ethylene structure and the branched ethylene structure in the ethylene-vinyl acetate copolymer. In the present invention, by using an ethylene-vinyl acetate copolymer having a branching degree measured by 13C-NMR within this range, for a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less, for which the effect cannot be obtained with existing additives, the pour point can be lowered and the fluidity at low temperatures can be improved. The kinematic viscosity at 50 °C is 3.0 to 450 mm 2From the perspective of further lowering the pour point of fuel oil with a sulfur content of 0.53% by mass or less, the degree of branching measured by 13C-NMR of the ethylene-vinyl acetate copolymer is preferably 0.95 to 3.0%, more preferably 1.0 to 2.0%. In the present invention, the degree of branching measured by 13C-NMR of the ethylene-vinyl acetate copolymer is more specifically based on the method described on pages 74 to 78 of (1) of the Journal of the Chemical Society of Japan, 1980. From the 13C-NMR spectrum of the ethylene-vinyl acetate copolymer, signals corresponding to the carbon atoms of the branched terminal methyl group, the main chain methylene group, the α-position of the acetoxyl group, and the β-position of the acetoxyl group are identified respectively. Based on the integral values of each signal, the degree of branching (%) = <[Integral value of the signal corresponding to the branched terminal methyl group] / ([Integral value of the signal corresponding to the branched terminal methyl group] + [Integral value of the signal corresponding to the main chain methylene group] + [Integral value of the signal corresponding to the α-position of the acetoxyl group] + [Integral value of the signal corresponding to the β-position of the acetoxyl group]) × 100> is calculated.

[0016] The detailed measurement conditions for the degree of branching measured by 13C-NMR of the ethylene-vinyl acetate copolymer are as follows. ·Degree of branching measurement conditions 13C-NMR apparatus: JNM ECA-600 (manufactured by JEOL Ltd.) Magnetic field strength: 600 MHz Scans: 16000 times Relaxation delay: 4 seconds Temperature: 135 °C Solvent: o-dichlorobenzene

[0017] The melting temperature of the ethylene-vinyl acetate copolymer used in the present invention is not particularly limited, but the kinematic viscosity at 50 °C is 3.0 to 450 mm 2 From the perspective of further lowering the pour point of fuel oil with a sulfur content of 0.53% by mass or less, the melting temperature is preferably 50 to 75 °C, more preferably 55 to 70 °C. In the present invention, the melting temperature of the ethylene-vinyl acetate copolymer is measured by differential scanning calorimetry in accordance with ISO 11357-3 (2018).

[0018] The method for producing the ethylene-vinyl acetate copolymer used in the present invention is not particularly limited. A method of polymerizing constituent monomers containing ethylene and vinyl acetate by a known method to obtain an ethylene-vinyl acetate copolymer having a weight average molecular weight Mw of 50,000 to 250,000, a vinyl acetate content in the constituent monomers of 25 to 40% by mass, and a branching degree measured by 13C-NMR of 0.90 to 4.0% can be mentioned. The polymerization method at this time is not particularly limited, and for example, suspension polymerization, solution polymerization, gas phase polymerization, etc. can be used for polymerization. At this time, even without using a catalyst, a catalyst such as an organic or inorganic peroxide or an azo compound may be used.

[0019] The additive of the present invention is composed of the above-described ethylene-vinyl acetate copolymer and is an additive for fuel oil having a kinematic viscosity at 50°C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53% by mass or less. In the present invention, for such fuel oils for which the effects cannot be obtained with existing additives, by using an additive composed of the above-described ethylene-vinyl acetate copolymer, the pour point of the fuel oil can be lowered to improve the fluidity at low temperatures. From the viewpoint of further obtaining the effects of the present invention, the additive of the present invention is preferably used for fuel oils having a kinematic viscosity at 50°C of 4.0 to 400 mm 2 / s, more preferably used for fuel oils having a kinematic viscosity at 50°C of 5.0 to 300 mm 2 / s, and even more preferably used for fuel oils having a kinematic viscosity at 50°C of 6.0 to 150 mm 2 / s. In the present invention, the kinematic viscosity of the fuel oil at 50°C is measured by the method described in JIS K 2283 (2000).

[0020] Further, from the viewpoint of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil having a sulfur content of 0.50% by mass or less, and more preferably used in a fuel oil having a sulfur content of 0.48% by mass or less. Further, from the viewpoint of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil having a sulfur content of 0.01% by mass or more, more preferably used in a fuel oil having a sulfur content of 0.05% by mass or more, even more preferably used in a fuel oil having a sulfur content of 0.10% by mass or more, and even more preferably used in a fuel oil having a sulfur content of 0.20% by mass or more. In the present invention, the sulfur content of the fuel oil is measured by the ultraviolet fluorescence method described in JIS K 2541-6 (2003).

[0021] Further, from the viewpoint of obtaining the effects of the present invention more effectively, the additive of the present invention has a density at 15°C of 820 to 980 kg / m 3 and is preferably used in a fuel oil, more preferably used in a fuel oil having a density at 15°C of 840 to 975 kg / m 3 even more preferably used in a fuel oil having a density at 15°C of 860 to 970 kg / m 3 and even more preferably used in a fuel oil having a density at 15°C of 880 to 970 kg / m 3 and even more preferably used in a fuel oil. In the present invention, the density of the fuel oil at 15°C is measured by the method described in JIS K 2249 (2011).

[0022] Further, from the viewpoint of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil having a pour point of -40°C to 30°C, more preferably used in a fuel oil having a pour point of -30°C to 25°C, even more preferably used in a fuel oil having a pour point of -20°C to 20°C, and even more preferably used in a fuel oil having a pour point of -10°C to 15°C. In the present invention, the pour point of the fuel oil is measured by the method described in JIS K 2269 (1987).

[0023] Furthermore, from the perspective of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil having an asphaltene content of 0.10 to 15% by mass as measured by the TLC / FID method, more preferably used in a fuel oil having an asphaltene content of 0.20 to 12% by mass as measured by the TLC / FID method, even more preferably used in a fuel oil having an asphaltene content of 0.30 to 10% by mass as measured by the TLC / FID method, and even more preferably used in a fuel oil having an asphaltene content of 0.50 to 8.0% by mass as measured by the TLC / FID method. In the present invention, the asphaltene content of the fuel oil as measured by the TLC / FID method can be determined in more detail by separating the components in the fuel oil by TLC (thin layer chromatography) based on SARA analysis in accordance with JPI-5S-77-2019 and calculating the peak area ratio of the asphaltene in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0024] Furthermore, from the perspective of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil having a saturate content of 10 to 70% by mass as measured by the TLC / FID method, more preferably used in a fuel oil having a saturate content of 15 to 60% by mass as measured by the TLC / FID method, even more preferably used in a fuel oil having a saturate content of 20 to 50% by mass as measured by the TLC / FID method, and even more preferably used in a fuel oil having a saturate content of 25 to 45% by mass as measured by the TLC / FID method. In the present invention, the saturate content of the fuel oil as measured by the TLC / FID method can be determined in more detail by separating the components in the fuel oil by TLC (thin layer chromatography) based on SARA analysis in accordance with JPI-5S-77-2019 and calculating the peak area ratio of the saturate in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0025] Further, from the viewpoint of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil having an aromatic content of 30 to 75% by mass measured by the TLC / FID method, more preferably used in a fuel oil having an aromatic content of 35 to 70% by mass measured by the TLC / FID method, even more preferably used in a fuel oil having an aromatic content of 40 to 65% by mass measured by the TLC / FID method, and even more preferably used in a fuel oil having an aromatic content of 45 to 65% by mass measured by the TLC / FID method. In the present invention, the aromatic content of the fuel oil measured by the TLC / FID method can be determined in more detail by separating the components in the fuel oil by TLC (thin layer chromatography) based on SARA analysis in accordance with JPI-5S-77-2019 and calculating the peak area ratio of the aromatic components in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0026] Further, from the viewpoint of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil having a resin content of 0.50 to 25% by mass measured by the TLC / FID method, more preferably used in a fuel oil having a resin content of 1.0 to 20% by mass measured by the TLC / FID method, even more preferably used in a fuel oil having a resin content of 2.0 to 18% by mass measured by the TLC / FID method, and even more preferably used in a fuel oil having a resin content of 2.5 to 16% by mass measured by the TLC / FID method. In the present invention, the resin content of the fuel oil measured by the TLC / FID method is calculated by separating the components in the fuel oil by TLC (thin layer chromatography) based on SARA analysis in accordance with JPI-5S-77-2019 and calculating the peak area ratio of the resin components in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0027] Further, from the viewpoint of obtaining the effects of the present invention more effectively, the additive of the present invention is preferably used in a fuel oil in which the content ratio of the asphaltene content to the saturated content in the fuel oil [asphaltene content / saturated content] is 0.0010 to 1.0, more preferably used in a fuel oil in which the content ratio is 0.0050 to 0.60, even more preferably used in a fuel oil in which the content ratio is 0.010 to 0.40, and even more preferably used in a fuel oil in which the content ratio is 0.010 to 0.40.

[0028] The additive of the present invention is not particularly limited as long as it is an additive used in a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less, and can be used. For example, it can be an additive used in automotive fuel oil, marine fuel oil, aircraft fuel oil, railway vehicle fuel oil, agricultural machinery fuel oil, construction machinery fuel, etc. Among these, the additive of the present invention preferably has a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and is used in marine fuel oil having a sulfur content of 0.53 mass% or less.

[0029] By adding the additive of the present invention to a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less in an amount of 0.01 mass ppm to 10,000 mass ppm, the pour point of the fuel oil can be lowered.

[0030] The fuel oil composition of the present invention is a fuel oil composition containing the above-described additive and a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less. Such a fuel oil has a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s, there is no particular limitation as long as it is a fuel oil with a sulfur content of 0.53% by mass or less, and it is appropriately selected according to the purpose of use and conditions. For example, special No. 1 light oil, No. 1 light oil, No. 2 light oil, No. 3 light oil, special No. 3 light oil, A heavy oil, B heavy oil, C heavy oil, No. 1 kerosene, No. 2 kerosene, MGO (Marine Gas Oil), MFO (Marine Fuel Oil), MDO (Marine Diesel Oil), MDF (Marine Diesel Fuel), HFO (Heavy Fuel Oil), RFO (Residual Fuel Oil), LSMGO (Low Sulfur Marine Gas Oil), LSMDO (Low Sulfur Marine Diesel Oil), VLSFO (Very Low Sulfur Fuel Oil), ULSFO (Ultra Low Sulfur Fuel Oil), palm oil, coconut oil, rapeseed oil, soybean oil, sunflower oil, corn oil, sesame oil, tall oil, bone oil, whale oil, etc. One or more of these can be used. Among these, as light oil or heavy oil, straight-run light oil fraction, vacuum gas oil fraction, desulfurized light oil fraction, cracked base oil fraction, straight desulfurized light oil fraction, atmospheric distillation residue, vacuum distillation residue, straight desulfurized heavy oil, cracked heavy oil, etc. may be used, or these may be used after hydrotreating. In the present invention, when the fuel oil consists of a mixture of two or more kinds of fuel oils, values such as kinematic viscosity and sulfur content at 50 °C are the values measured using the fuel oil as a mixture. Generally, fuel oils called light oil, A heavy oil, MGO, and MDO often have a kinematic viscosity at 50 °C of less than 3.0 mm 2 / s, and fuel oils called C heavy oil often have a kinematic viscosity at 50 °C greater than 450 mm 2 / s. Therefore, in the present invention, it is preferable to prepare and use a fuel oil whose kinematic viscosity is within the specified range by mixing with other types of fuel oils respectively.

[0031] The kinematic viscosity at 50 °C of the fuel oil used in the fuel oil composition of the present invention is preferably 4.0 to 400 mm 2 / s from the viewpoint of obtaining the effects of the present invention more preferably, 5.0 to 300 mm 2 / s, and even more preferably 6.0 to 150 mm 2It is more preferably at / s. In the present invention, the kinematic viscosity of the fuel oil at 50 °C is measured by the method described in JIS K 2283 (2000).

[0032] From the viewpoint of obtaining the effects of the present invention more effectively, the sulfur content in the fuel oil used in the fuel oil composition of the present invention is preferably 0.50% by mass or less, and more preferably 0.48% by mass or less. Also, from the viewpoint of obtaining the effects of the present invention more effectively, the sulfur content in the fuel oil used in the fuel oil composition of the present invention is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.10% by mass or more, and still more preferably 0.20% by mass or more. In the present invention, the sulfur content of the fuel oil is measured by the ultraviolet fluorescence method described in JIS K 2541-6 (2003).

[0033] From the viewpoint of obtaining the effects of the present invention more effectively, the density of the fuel oil used in the fuel oil composition of the present invention at 15 °C is 820~980 kg / m 3 and preferably, 840~975 kg / m 3 more preferably, 860~970 kg / m 3 still more preferably, 880~970 kg / m 3 and still more preferably. In the present invention, the density of the fuel oil at 15 °C is measured by the method described in JIS K 2249 (2011).

[0034] From the viewpoint of obtaining the effects of the present invention more effectively, the pour point of the fuel oil used in the fuel oil composition of the present invention is preferably -40 °C to 30 °C, more preferably -30 °C to 25 °C, still more preferably -20 °C to 20 °C, and still more preferably -10 °C to 15 °C. In the present invention, the pour point of the fuel oil is measured by the method described in JIS K 2269 (1987).

[0035] Also, the pour point of the fuel oil composition of the present invention is preferably from -40°C to 10°C, more preferably from -30°C to 7.5°C, even more preferably from -20°C to 7.5°C, and even more preferably from -10°C to 5.0°C. The pour point of the fuel oil composition of the present invention is also measured by the method described in JIS K 2269 (1987).

[0036] From the viewpoint of obtaining the effects of the present invention more effectively, the content of asphaltene measured by the TLC / FID method in the fuel oil used in the fuel oil composition of the present invention is preferably 0.10 to 15% by mass, more preferably 0.20 to 12% by mass, even more preferably 0.30 to 10% by mass, and even more preferably 0.50 to 8.0% by mass. In the present invention, the content of asphaltene measured by the TLC / FID method of the fuel oil can be determined more specifically by separating the components in the fuel oil by TLC (thin layer chromatography) in accordance with JPI-5S-77-2019 and calculating the peak area ratio of asphaltene in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0037] From the viewpoint of obtaining the effects of the present invention more effectively, the content of saturates measured by the TLC / FID method in the fuel oil used in the fuel oil composition of the present invention is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, even more preferably 20 to 50% by mass, and even more preferably 25 to 45% by mass. In the present invention, the content of saturates measured by the TLC / FID method of the fuel oil can be determined more specifically by separating the components in the fuel oil by TLC (thin layer chromatography) in accordance with JPI-5S-77-2019 and calculating the peak area ratio of saturates in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0038] In the fuel oil used in the fuel oil composition of the present invention, the content of aromatic components measured by the TLC / FID method is preferably 30 to 75% by mass, more preferably 35 to 70% by mass, even more preferably 40 to 65% by mass, and even more preferably 45 to 65% by mass from the viewpoint of obtaining the effects of the present invention more effectively. In the present invention, the content of aromatic components measured by the TLC / FID method of the fuel oil can be determined more specifically by separating the components in the fuel oil by TLC (thin layer chromatography) in accordance with JPI-5S-77-2019 and calculating the peak area ratio of the aromatic components in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0039] In the fuel oil used in the fuel oil composition of the present invention, the content of resin components measured by the TLC / FID method is preferably 0.50 to 25% by mass, more preferably 1.0 to 20% by mass, even more preferably 2.0 to 18% by mass, and even more preferably 2.5 to 16% by mass from the viewpoint of obtaining the effects of the present invention more effectively. In the present invention, the content of resin components measured by the TLC / FID method of the fuel oil can be determined more specifically by separating the components in the fuel oil by TLC (thin layer chromatography) in accordance with JPI-5S-77-2019 and calculating the peak area ratio of the resin components in the chromatogram obtained using an FID (hydrogen flame ionization detector).

[0040] The content ratio of the asphaltene content to the saturated content [asphaltene content / saturated content] in the fuel oil used in the fuel oil composition of the present invention is preferably 0.0010 to 1.0, more preferably 0.0050 to 0.60, even more preferably 0.010 to 0.40, and even more preferably using a fuel oil having a content ratio of 0.010 to 0.40 from the viewpoint of obtaining the effects of the present invention more effectively.

[0041] By adopting the above-described configuration, the fuel oil composition of the present invention has excellent fluidity even when exposed to a low-temperature environment in winter or in cold regions. The fuel oil composition of the present invention may further contain other additives according to purposes such as improving combustibility, storage stability, oxidation stability, abrasion resistance, uniformity, safety, environmental compatibility, startability, low-temperature fluidity, and handleability. Examples of other additives include surface ignition inhibitors, octane number improvers, cetane number improvers, antibacterial and fungicidal agents, rust preventives, deposit improvers, antioxidants, metal deactivators, antiwear agents, detergents and dispersants, icing inhibitors, antiknock agents, corrosion preventives, antistatic agents, combustion aids, dyes, etc., and one or more of these can be used.

[0042] Examples of surface ignition inhibitors include organic phosphorus compounds such as tributyl phosphite, trimethyl phosphite, tricresyl phosphate, tricyclohexyl phosphate, cresyl diphenyl phosphate, trimethyl phosphate, and methyl phenyl phosphate; and organic boron compounds such as 2-ethylhexyl boronate and butyl diisobutyl boronate. One or more of these can be used. The content of the surface ignition inhibitor is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0043] Examples of octane number improvers include methanol, ethanol, butanol, butyl acetate, methyl tert-butyl ether, ethyl tert-butyl ether, methyl tert-amyl ether, N-methylaniline, methylcyclopentadienyl manganese tricarbonyl, tetraethyl lead, etc. One or more of these can be used. The content of the octane number improver is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0044] As cetane number improvers, for example, there are aliphatic nitrates such as ethyl nitrate, methoxyethyl nitrate, isopropyl nitrate, amyl nitrate, hexyl nitrate, heptyl nitrate, octyl nitrate, 2-ethylhexyl nitrate, cyclohexyl nitrate, etc.; peroxides such as di-tert-butyl peroxide, etc. One or more of these can be used. The content of the cetane number improver is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0045] As antibacterial and bactericidal agents, for example, there are inorganic bactericides such as silver sulfate, silver nitrate, zinc sulfate, zinc nitrate, copper sulfate, ethylenediaminetetraacetic acid copper, etc.; organic nitrogen-based antibacterial agents such as hexahydro-1,3,5-tris(2-hydroxyethyl)-triazine, etc.; organic bromine-based antibacterial agents such as 2,2-dibromo-3-nitrilopropionamide, 1,4-bis(bromoacetoxy)-2-ethane, bistribromomethyl sulfone, etc., and isothiazoline-based antibacterial agents such as 2-methyl-4-isothiazolin-3-one, 2-methyl-4,5-trimethylene-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-n-octylisothiazolin-3-one, 4,5-dichloro-2-n-octylisothiazolin-3-one, 1,2-benzisothiazolin-3-one, N-n-butyl-1,2-benzisothiazolin-3-one, etc. One or more of these can be used. The content of the antibacterial and bactericidal agent is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0046] As rust inhibitors, for example, there are aliphatic amines and their salts, organic phosphoric acid esters, organic sulfonates, etc. One or more of these can be used. The content of the rust inhibitor is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0047] Examples of the sediment improver include tricresyl phosphate, trimethyl phosphate, tris(chloroethyl) phosphate, polypropylene, polybutene, polyisobutyleneamine, polyetheramine, polyalkylamine, polyoxyalkyleneamine, polyalkylphenoxyaminoalkane, polyalkylen succinimide, etc., and one or more of these can be used. The content of the sediment improver is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0048] Examples of the antioxidant include amine antioxidants such as N,N'-diisopropyl-p-phenylenediamine, N,N'-dibutyl-p-phenylenediamine, N,N'-dioctyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-ditoly-p-phenylenediamine, N-tolyl-N'-xylyl-p-phenylenediamine; phenolic antioxidants such as 2-t-butylphenol, 2,6-ditertiarybutylphenol, 2,6-ditertiarybutyl-4-methylphenol, 2,4-dimethyl-6-tertiarybutylphenol, 2,4,6-tri-t-butylphenol; sulfur antioxidants such as dilauryl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, lauryl stearyl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl β,β'-thiodibutyrate, dilauryl sulfide, etc., and one or more of these can be used. The content of the antioxidant is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0049] Examples of the metal deactivator include amino compounds such as ethylenediamine; salicylidene compounds such as N,N'-disalicylidene-1,2-diaminopropane, N,N'-disalicylidene-2-cyclohexanediamine, N,N'-disalicylideneethylenediamine, N,N'-bis(dimethylsalicylidene)ethylenediamine, N,N'-bis(dimethylsalicylidene)ethylenetetramine, and salicylaldoxime; triazole compounds such as 1-[(bis(2-ethylhexyl)aminomethyl]-1,2,4-triazole, 1-(1-butoxyethyl)-1,2,4-triazole, 4,4'-methylenebis(2-undecyl-5-methylimidazole), and bis[(N-methyl)imidazol-2-yl]carbinol octyl ether; benzotriazole compounds such as 4-alkylbenzotriazole, 4,5,6,7-tetrahydrobenzotriazole, 5,5'-methylenebisbenzotriazole, 1-[(bis(2-ethylhexyl)aminomethyl)triazole, 1-[(bis(2-ethylhexyl)aminomethyl)benzotriazole, 1-(nonyloxymethyl)benzotriazole, and 1-(1-butoxyethyl)benzotriazole. One or more of these can be used. The content of the metal deactivator is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0050] Examples of the antiwear agent include sulfur-based antiwear agents such as sulfurized oils and fats, olefin polysulfides, sulfurized olefins, dibenzyl sulfide, ethyl-3-[[bis(1-methylethoxy)phosphinothioyl]thio]propionate, tris-[(2- or 4)-isoalkylphenol] thiophosphate, 3-(di-isobutoxy-thiophosphorylthio)-2-methyl-propionic acid, triphenyl phosphorothionate, β-dithiophosphorylated propionic acid, methylenebis(dibutyldithiocarbamate), O,O-diisopropyl-dithiophosphorylethyl propionate, 2,5-bis(n-nonyldithio)-1,3,4-thiadiazole, 2,5-bis(1,1,3,3-tetramethylbutanethio)1,3,4-thiadiazole, and 2,5-bis(1,1,3,3-tetramethyldithio)-1,3,4-thiadiazole; phosphorus-based compounds such as monooctyl phosphate, dioctyl phosphate, trioctyl phosphate, monobutyl phosphate, dibutyl phosphate, tributyl phosphate, monophenyl phosphate, diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, monoisopropylphenyl phosphate, diisopropylphenyl phosphate, triisopropylphenyl phosphate, monoteritary butylphenyl phosphate, di-tert-butylphenyl phosphate, tri-tert-butylphenyl phosphate, triphenyl thiophosphate, monooctyl phosphite, dioctyl phosphite, trioctyl phosphite, monobutyl phosphite, dibutyl phosphite, tributyl phosphite, monophenyl phosphite, diphenyl phosphite, triphenyl phosphite, monoisopropylphenyl phosphite, diisopropylphenyl phosphite, triisopropylphenyl phosphite, mon-tert-butylphenyl phosphite, di-tert-butylphenyl phosphite, and tri-tert-butylphenyl phosphite; fatty acids such as caprylic acid, 2-ethylhexanoic acid, pelargonic acid, isononanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid;Organometallic compounds such as metal naphthenates, metal fatty acid salts, metal phosphates, metal phosphate esters, and metal phosphite esters; other examples include boron compounds, alkylamine salts of mono- and dihexyl phosphates, amine salts of phosphate esters, and mixtures of triphenyl thiophosphate ester and tert-butylphenyl derivatives. The content of the antiwear agent is not particularly limited, but for example, it is preferably 0.01 to 10% by mass based on the total amount of the fuel oil composition.;

[0051] Examples of the detergent-dispersant include phosphoric acid amides, aminoalkanes, alkylamine phosphate esters, polyetheramines, polybutenylamines, alkenyl succinimides, alkenyl succinate esters, metal salts of salicylic acid, metal salts of sulfonic acid, metal salts of carboxylic acid, metal salts of phosphonic acid, etc., and one or more of these can be used. The content of the detergent-dispersant is not particularly limited, but for example, it is preferably 0.001 to 10% by mass based on the total amount of the fuel oil composition.

[0052] The fuel oil composition of the present invention can be used without particular limitation as long as it is in the form of using a liquid fuel oil. For example, it can be used as fuel oil for automobiles such as passenger cars and trucks, fuel oil for ships such as passenger ships and cargo ships, fuel oil for aircraft such as airplanes and helicopters, fuel oil for railway vehicles such as diesel locomotives, fuel oil for agricultural machinery, fuel oil for construction machinery, etc. Among these, it is preferably used as fuel oil for ships.

Examples

[0053] Hereinafter, the present invention will be described more specifically by way of examples. In the following examples, % is based on mass unless otherwise specified.

[0054] <Production of ethylene vinyl acetate copolymer (EVA)> Ethylene and vinyl acetate were used as constituent monomers and polymerized by a known method to produce ethylene-vinyl acetate copolymers EVA1 to EVA14. The weight-average molecular weight Mw, number-average molecular weight Mn, weight-average molecular weight Mw / number-average molecular weight Mn, branching degree, and melting temperature are shown in Table 1. The constituent monomer ratio of each ethylene-vinyl acetate copolymer EVA was measured by the method described in JIS K 7192 (1999) to calculate the vinyl acetate content. The melting temperatures of EVA1 to EVA14 were determined using a differential scanning calorimeter (micro DSC7 evo, manufactured by SETARAM) by differential scanning calorimetry in accordance with ISO 11357-3 (2018).

[0055]

Table 1

[0056] <Preparation of fuel oil composition> Using the produced ethylene-vinyl acetate copolymers EVA1 to EVA13 and fuel oils 1 to 8 described in Table 2 below, fuel oil compositions of the examples and comparative examples were prepared by adding EVA as an additive to the fuel oil as shown in Tables 3 to 6.

[0057] The kinematic viscosity of the fuel oil at 50 °C was measured using a kinematic viscometer (SVM 3001, manufactured by Anton Paar) in accordance with JIS K 2283 (2011). The sulfur content of the fuel oil was measured by the ultraviolet fluorescence method described in JIS K 2541-6 (2003). The density of the fuel oil at 15 °C was measured in accordance with the description in JIS K 2249 (2011). The contents of asphaltene, saturate, aromatic, and resin in the fuel oil were measured in accordance with JPI-5S-77-2019.

[0058] <Measurement of pour point> For each of the prepared fuel oil compositions, the pour point was measured by the method described in JIS K 2269 (1987). The measurement results are shown in Tables 3 to 6, respectively. In the present invention, if the pour point of the fuel oil is lowered by 12.5 °C or more due to the addition of the additive, or if the pour point is lowered by 7.5 °C or more and becomes 0 °C or less, it indicates that the additive has practicality as a pour point depressant.

[0059] [Table 2]

[0060] [Table 3]

[0061] [Table 4]

[0062] [Table 5]

[0063] [Table 6]

[0064] According to the ethylene-vinyl acetate copolymer of the present invention, even for fuel oils having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less, for which no effect can be obtained with existing additives produced in Comparative Examples 1 to 6, the pour point could be lowered. Therefore, the additive of the present invention has been shown to be widely useful as an additive for various fuel oils used in internal combustion engines, ships, aircraft, external combustion engines, etc., having a kinematic viscosity at 50 °C of 3.0 to 450 mm 2 / s and a sulfur content of 0.53 mass% or less.

Claims

Claim 1 An ethylene-vinyl acetate copolymer having a weight average molecular weight Mw of 50,000 to 250,000, a vinyl acetate content in the constituent monomers of 25 to 40% by mass, and a branching degree measured by 13C-NMR of 0.90 to 4.0%, and having a kinematic viscosity at 50 °C of 3.0 to 450 mm ２ / s and a sulfur content of 0.53% by mass or less, which is an additive for fuel oil. Claim 2 The fuel oil is marine fuel oil, and the additive according to claim 1. Claim 3 The additive is a pour point depressant for fuel oil, and the additive according to claim 1 or 2. Claim 4 An additive according to any one of claims 1 to 3 and a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm ２ / s and a sulfur content of 0.53 mass% or less. Claim 5 The fuel oil composition according to claim 4, wherein the content of asphaltene measured by the TLC / FID method of the fuel oil is 0.10 to 15% by mass. Claim 6 The method for lowering the pour point of a fuel oil having a kinematic viscosity at 50 °C of 3.0 to 450 mm ２ / s and a sulfur content of 0.53 mass% or less, which comprises adding 0.01 mass ppm to 10,000 mass ppm of the additive according to any one of claims 1 to 3 to the fuel oil.

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