JPH0248033B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to pour point depressants for hydrocarbon fuel oils. The oil imported into Japan is gradually becoming heavier, and this trend is expected to intensify in the future. On the other hand, demand for heavy oil is decreasing due to the shift away from petroleum for thermal power generation, but on the other hand, demand for medium and light oil is on the rise, as it is mainly used in the civil and transportation sectors. In order to respond to such a supply and demand situation, there is a movement to utilize a portion of heavy oil fractions to produce medium and light oils, and in particular, middle distillates such as light oil and A-heavy oil are becoming heavier. However, such heavy fuel oil has a high pour point and loses fluidity at low temperatures, so it is often difficult to use it in the same way as conventional light and medium oils. Many pour point depressants have been disclosed for the purpose of solving this problem, and among them, many are related to ethylene/ethylenically unsaturated ester copolymers. Furthermore, most commercially available pour point depressants for fuel oil are ethylene/vinyl acetate copolymers, which are well known to have a large pour point depressing effect. However, when the present inventors investigated the actual addition of this ethylene/vinyl acetate copolymer to fuel oil, the ethylene/vinyl acetate copolymer obtained from a commercially available pour point depressant was solid and had a low softening temperature. It was found that in order to add it to fuel oil, it was necessary to add a large amount of solvent in advance to dissolve it. As described above, the ethylene/vinyl acetate copolymer, which is the active ingredient of pour point depressants currently on the market, not only has poor solubility but also has extremely low fluidity, making it extremely difficult to use. . As a result of intensive research to improve solubility and fluidity without reducing pour point depressing performance, the inventors found that when the ratio of ethylene to ethylenically unsaturated ester is in a specific range, They discovered that it has excellent properties and fluidity, leading to the completion of the present invention. That is, the present invention has an ethylenically unsaturated ester monomer content of 50 to 65% by weight and a number average molecular weight of 500 to 65% by weight.
10,000 and has 1 to 15 methyl terminal side chains per 100 methylene groups in addition to the methyl groups of the ethylenically unsaturated ester monomer. It is a pour point depressant for use. Examples of the ethylenically unsaturated ester monomer forming the ethylene/ethylenically unsaturated ester copolymer of the present invention include vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl octoate, and vinyl stearate; or methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, octyl acrylate, octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, stearyl acrylate, stearyl methacrylate, etc. Examples include acrylic esters and methacrylic esters, and one or more of these can be used. The ethylene/ethylenic unsaturated ester monomer content of the ethylene/ethylenic unsaturated ester copolymer used in the present invention is 50 to 65% by weight, and 65% by weight.
If it exceeds 50% by weight, the pour point depressing performance will decrease, and if it is less than 50% by weight, solubility and fluidity will decrease. The number average molecular weight of the ethylene/ethylenic unsaturated ester copolymer used in the present invention is from 500 to
10,000, preferably 1,000 to 5,000. If the number average molecular weight exceeds 10,000, the solubility and fluidity will deteriorate, and if it is less than 500, the pour point lowering performance will not be sufficient. The number of methyl-terminated side chains per 100 methylene groups other than methyl groups in the ethylenically unsaturated ester monomer of the ethylene/ethylenic unsaturated ester copolymer used in the present invention is 1 to 15, and within this range. If it deviates from this, the pour point lowering performance will deteriorate. Note that the methyl terminal side chain can be measured by nuclear magnetic resonance. The ethylene/ethylenic unsaturated ester copolymer used in the present invention can be produced by a known method, for example, by free radical bulk polymerization, emulsion polymerization or solution polymerization. The pour point depressant for fuel oil of the present invention has a concentration of 5 to 10,000 ppm, based on fuel oil such as kerosene, light oil, and heavy oil.
Preferably used in the range of 10-5000ppm,
If it is less than 5ppm, the pour point lowering performance is not sufficient.
Even if it is used in excess of 10,000 ppm, no further improvement in pour point reduction performance is observed. Furthermore, when using the pour point depressant for fuel oil of the present invention, it can be used in combination with commonly used rust inhibitors, antioxidants, antistatic agents, anticorrosive agents, anti-sludge agents, or other additives. . The effects of the present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Examples The pour point depressing performance, solubility and fluidity of the ethylene/ethylenically unsaturated ester copolymer of the present invention were evaluated by the following methods. Pour point depressing performance was evaluated by using a gas oil fraction with the following properties, adding a specified amount of ethylene/ethylenic unsaturated ester copolymer to it, heating it to 90°C, and stirring until it was completely dissolved. After mixing and cooling to 25° C., the pour point was measured according to JIS-K2269-1980. (1) Distillation properties Initial boiling point 176℃ 10% distillation point 220℃ 50% distillation point 282℃ 90% distillation point 337℃ End point 356℃ (2) Cloud point -5℃ (3) Pour point -10℃ To evaluate the solubility, put 1 g of the ethylene/ethylenic unsaturated ester copolymer from which the solvent component has been removed in advance and 9 g of xylene in a 30 ml test tube, seal it with a rubber stopper, and mix it with shaking at 25°C to dissolve it. I saw the difficulty. Evaluation: ◎ Dissolves with a little shaking. Evaluation 〇 Dissolves when shaken vigorously. Rating × Hardly melts. Fluidity was evaluated by standing the ethylene/ethylenic unsaturated ester copolymer from which the solvent component had been removed in advance at 25°C, then tilting the container and observing the flow. Evaluation ◎ Flows easily. Evaluation 〇 High viscosity and gradual flow. Evaluation × Solid state and does not flow at all. These evaluation results are shown in Table-1. The degree of branching of the ethylene/ethylenic unsaturated ester copolymer in Table 1 is the number of methyl terminal side chains other than the methyl group of the ethylenically unsaturated ester monomer of the copolymer. Comparative Example In place of the ethylene/ethylenically unsaturated ester copolymer of the present invention, a component obtained by removing volatile components from a commercially available pour point depressant for gas oil was used, and evaluation was conducted in the same manner as in the example. The results are shown in Table 1.

[Table] From the evaluation results in Table 1, it can be seen that all the ethylene/vinyl acetate copolymers used in commercially available fluidity improvers for diesel oil have poor solubility and fluidity.
The ethylene/ethylenic unsaturated ester copolymer of the present invention has a pour point as low as that of commercially available copolymers, and has good solubility and fluidity, so it does not need to be diluted with a large amount of solvent as much as 50% by weight. You can see that it can be used.

Claims (1)

[Claims] 1 Ethylenically unsaturated ester monomer content 50~
Ethylene/ethylenically unsaturated with 65% by weight, number average molecular weight of 500 to 10,000, and 1 to 15 methyl terminal side chains per 100 methylene groups in addition to the methyl groups of the ethylenically unsaturated ester monomer. Pour point depressant for fuel oil consisting of an ester copolymer. 2. The pour point depressant for fuel oil according to claim 1, wherein the ethylene/ethylenically unsaturated ester copolymer is an ethylene/vinyl acetate copolymer.