JP7061942B2 - Process oil and rubber composition - Google Patents

Description

The present invention relates to process oils and rubber compositions.

Rubber used in the fields of machinery, electrical products, etc. is generally blended with process oil for the purpose of improving mechanical properties, workability, and the like. The properties required for process oils vary depending on the application of the rubber. For example, the process oil blended in rubber used for interior materials for automobiles is required to have weather resistance. As such a process oil, a process oil having an ultraviolet absorbance (198 nm) of 3 or less, an ultraviolet absorbance (228 nm) of 1 or less, and a 40 ° C. kinematic viscosity of 25 mm ² / s or more and 450 mm ² / s or less is known. (Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-194164

However, the conventional process oil as described in Patent Document 1 has a problem in terms of bleed resistance. That is, the process oil is used by kneading it into rubber, but since the conventional process oil is not sufficiently compatible with the rubber, a phenomenon (bleeding) in which the process oil oozes out on the rubber surface may occur.

Therefore, an object of the present invention is to provide a process oil and a rubber composition having both weather resistance and bleed resistance.

The present inventors have found that it is very difficult to achieve both weather resistance and bleed resistance, but it is possible to achieve both by using a process oil having specific properties. That is, in the present invention, the kinematic viscosity at 75 ° C. is 5 mm ² / s or more and 100 mm ² / s or less, the viscosity specific gravity constant is 0.700 or more and 0.900 or less, and the absorbance at 198 nm exceeds 3. Provided is a process oil having an absorbance of 6 or less, an absorbance at 228 nm of more than 1.3 and 3.5 or less, and an aniline point of 100 ° C. or higher and 200 ° C. or lower.

In the above process oil, the refractive index section may be 1.04 or more and 1.05 or less, the 10% distillation temperature may be 300 ° C. or more and 600 ° C. or less, and the iodine value is 1.0 gI _2/100 g. The acid value may be 0.10 mgKOH / g or less.

The present invention also provides a rubber composition containing a rubber component and the above-mentioned process oil.

According to the present invention, it is possible to provide a process oil and a rubber composition having both weather resistance and bleed resistance.

The process oil according to this embodiment has the following properties. As a result, the process oil can have both weather resistance and bleed resistance.
(1) The kinematic viscosity at 75 ° C. is 5 mm ² / s or more and 100 mm ² / s or less.
(2) The viscosity specific gravity constant is 0.700 or more and 0.900 or less.
(3) The absorbance at 198 nm is more than 3 and 3.6 or less.
(4) The absorbance at 228 nm exceeds 1.3 and is 3.5 or less.
(5) The aniline point is 100 ° C. or higher and 200 ° C. or lower.

The kinematic viscosity of the process oil at 75 ° C. is 5 mm ² / s or more and 100 mm ² / s or less, and from the viewpoint of further excellent weather resistance and bleed resistance, it is preferably 10 mm ² / s or more, more preferably 15 mm ² / s. The above is more preferably 18 mm ² / s or more, preferably 90 mm ² / s or less, more preferably 85 mm ² / s or less, still more preferably 80 mm ² / s or less. The kinematic viscosity in the present specification means the kinematic viscosity measured according to JIS K2283. The upper limit value and the lower limit value can be arbitrarily combined (hereinafter, the same applies).

The viscosity specific gravity constant (also referred to as VGC) of the process oil is 0.700 or more and 0.900 or less, and is preferably 0.720 or more, more preferably 0.740, from the viewpoint of further excellent weather resistance and bleed resistance. The above is more preferably 0.760 or more, particularly preferably 0.780 or more, and preferably 0.898 or less, more preferably 0.896 or less, still more preferably 0.894 or less, and particularly preferably 0. It is 892 or less. The viscosity specific gravity constant in the present specification means the viscosity specific gravity constant measured according to ASTM D2140.

The absorbance of the process oil at 198 nm is more than 3 and 3.6 or less, and from the viewpoint of further excellent weather resistance and bleed resistance, it is preferably 3.05 or more, more preferably 3.10 or more, still more preferably 3. It is 15 or more, particularly preferably 3.20 or more, preferably 3.58 or less, more preferably 3.56 or less, still more preferably 3.54 or less, and particularly preferably 3.52 or less. Absorbance in the present specification means the absorbance measured according to JIS K0115.

The absorbance of the process oil at 228 nm is more than 1.3 and 3.5 or less, and is preferably 1.5 or more, more preferably 1.6 or more, still more preferably, from the viewpoint of further excellent weather resistance and bleed resistance. It is 1.7 or more, particularly preferably 1.8 or more, preferably 3.0 or less, more preferably 2.9 or less, still more preferably 2.8 or less, and particularly preferably 2.7 or less.

The aniline point of the process oil is 100 ° C. or higher and 200 ° C. or lower, preferably 110 ° C. or higher, more preferably 115 ° C. or higher, still more preferably 118 ° C. or higher, particularly preferably from the viewpoint of further excellent weather resistance and bleed resistance. Is 120 ° C. or higher, preferably 190 ° C. or lower, more preferably 180 ° C. or lower, still more preferably 175 ° C. or lower, and particularly preferably 170 ° C. or lower. The aniline point in the present specification means an aniline point measured according to JIS K2256.

The process oil having the above-mentioned properties may be a mineral oil. For example, the lubricating oil distillate obtained by atmospheric distillation and vacuum distillation of crude oil can be removed from the solvent, extracted with a solvent, hydrolyzed and decomposed with a solvent. It may be a mineral oil obtained by refining one kind alone or a combination of two or more kinds of refining treatments such as catalytic dewaxing, hydrorefining, sulfuric acid washing, and white clay treatment. The process oil may contain one or more of these mineral oils.

Specifically, first, a crude oil composed of paraffin-based crude oil, naphthen-based crude oil, etc. is heated to, for example, 350 ° C. in a heating furnace or the like, and then sent out to an atmospheric distillation column to be converted into petroleum steam inside the atmospheric distillation column and cooled. After that, it is separated in order from the one with the lowest boiling point to the one with the highest boiling point. As a result, for example, a normal pressure residual oil having a boiling point of 350 ° C. or higher is obtained. Fuel oil such as kerosene and light oil is taken out by atmospheric distillation, and the atmospheric residual oil flowing out from the bottom of the distillation column is distilled under reduced pressure. Then, the decompressed residual oil after fractional distillation of the reduced pressure light oil or the like is used as the lubricating oil distillate.

Subsequently, it is preferable to remove the solvent from the obtained lubricating oil fraction (residual oil under reduced pressure). In solvent removal, for example, a solvent such as liquefied propane is used to separate the lubricating oil distillate (reduced pressure residual oil) into oil (removal oil) and asphalt. In the removal by liquefied propane, the mixing ratio (volume ratio) of liquefied propane to the lubricating oil fraction (reduced pressure residual oil) may be, for example, 1 times or more or 4 times or more, and 9 times or less or 8 times or less. It may be there. The extraction temperature of the stripped oil in the solvent stripping may be 40 ° C. or higher, and may be 80 ° C. or lower.

The yield of degreased oil obtained by de-lubricating can prevent forming due to de-lubricating, stable production of de-lubricating oil, and the final obtained process oil at 75 ° C. From the viewpoint of facilitating the kinematic viscosity of 5 mm ² / s or more and 100 mm ² / s or less, it is preferably 30% by mass or more, more preferably 35% by mass, based on the total amount of the lubricating oil fraction (vacuum distillation residual oil). That is all.

Subsequently, in order to obtain a process oil having the above-mentioned properties, solvent extraction is performed, and the extraction temperature and solvent ratio (volume ratio of solvent / stripped oil) in the solvent extraction are adjusted within a predetermined range to obtain a hydrocarbon. It is preferable to obtain oil. The extraction temperature is preferably 40 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 80 ° C. or higher, preferably 140 ° C. or lower, more preferably 130 ° C. or lower, still more preferably 120 ° C. or lower. The solvent ratio (solvent / removal oil volume ratio) is preferably 0.4 or more, more preferably 1 or more, preferably 10 or less, and more preferably 7 or less.

Subsequently, the hydrocarbon oil is hydrogenated in the reaction tower (first reaction tower). Examples of the hydrogenation treatment include dewaxing treatment, hydrogenation treatment for aromatics, isomerization treatment and the like. As the catalyst to be filled in the first reaction column, a catalyst that is a catalyst poison such as hydrogen sulfide is used. As such a catalyst, for example, a catalyst in which a noble metal belonging to Group 10 of the Periodic Table is supported on a zeolite carrier is used. As the noble metal, platinum or palladium is preferably used. Since hydrogen sulfide becomes a catalyst poison in such a catalyst, it is preferable that the hydrogen sulfide concentration in the circulating hydrogen gas during normal operation is controlled to 500 volume ppm or less. The reaction conditions during steady operation in the first reaction column are, for example, a temperature of 250 to 410 ° C., a pressure (total pressure) of 3 to 20 MPa · G, and an LHSV (liquid spatiotemporal space velocity) of hydrocarbon oil 0.1 to 10 hr ⁻ . It is ¹ .

Subsequently, in another reaction tower (second reaction tower), hydrogenation finishing treatment of the hydrocarbon oil hydrotreated in the first reaction tower is performed. Examples of the hydrogenation finishing treatment include decolorization, desulfurization, denitrification, and deoxidation treatment. As the catalyst to be filled in the second reaction column, a complete pre-sulfurization catalyst is used. The complete pre-sulfurization catalyst is a catalyst in which a metal is supported in the form of an inorganic sulfur compound on an inorganic oxide-based carrier. The inorganic oxide-based carrier is not particularly limited, and examples thereof include silica, alumina, and silica-alumina. The metal is preferably a metal belonging to Group 6, 8, 9 or 10 of the Periodic Table, and is at least one kind of metal selected from these. Examples of the metal include nickel, cobalt, molybdenum, tungsten and the like.

The process oil preferably has the following properties in addition to the above (1) to (5) from the viewpoint of further improving the weather resistance and the bleed resistance.

The kinematic viscosity of the process oil at 40 ° C. is preferably 20.0 mm ² / s or more, more preferably 30.0 mm ² / s or more, still more preferably 40.0 mm ² / s or more, and particularly preferably 50.0 mm ² / s. s or more, preferably 500.0 mm ² / s or less, more preferably 480.0 mm ² / s or less, still more preferably 460.0 mm ² / s or less, particularly preferably 440.0 mm ² / s or less. be.

The kinematic viscosity of the process oil at 100 ° C. is preferably 5.00 mm ² / s or more, more preferably 6.00 mm ² / s or more, still more preferably 7.00 mm ² / s or more, and particularly preferably 8.00 mm ² / s or more. s or more, preferably 45.0 mm ² / s or less, more preferably 40.0 mm ² / s or less, still more preferably 35.0 mm ² / s or less, and particularly preferably 30.0 mm ² / s or less. be.

The viscosity index of the process oil is preferably 80 or more, more preferably 85 or more, still more preferably 90 or more, particularly preferably 95 or more, and preferably 140 or less, more preferably 130 or less, still more preferably 120 or less. Especially preferably 115 or less. The viscosity index in the present specification means a viscosity index measured according to JIS K2283.

The refractive index section (ri, Refractive Intercept) of the process oil is preferably 1.040 or more, more preferably _1.041 or more, still more preferably 1.043 or more, and preferably 1.050 or less. It is preferably 1.049 or less, more preferably 1.048 or less. The refractive index section ri in the present specification means the refractive index section ri measured according to ASTM _D2140 (calculated from the refractive index _{n D} ²⁰ at 20 ° C. and the density d at 20 ° C.).

The flash point of the process oil is preferably 200 ° C. or higher, more preferably 210 ° C. or higher, further preferably 220 ° C. or higher, particularly preferably 230 ° C. or higher, and preferably 350 ° C. or lower, more preferably 340 ° C. or lower. It is more preferably 330 ° C. or lower, and particularly preferably 320 ° C. or lower. The flash point in the present specification means a flash point measured according to JIS K2265-4 (Cleveland Opening (COC) method).

The pour point of the process oil is preferably −30 ° C. or higher, more preferably −25 ° C. or higher, still more preferably −20 ° C. or higher, particularly preferably −15 ° C. or higher, and preferably 15 ° C. or lower, more preferably. It is 10 ° C. or lower, more preferably 5 ° C. or lower, and particularly preferably 0 ° C. or lower. The pour point in the present specification means a pour point measured according to JIS K2269.

The acid value of the process oil is preferably 0.10 mgKOH / g or less, more preferably 0.08 mgKOH / g or less, still more preferably 0.04 mgKOH / g or less, and particularly preferably 0.02 mgKOH / g or less. The acid value in the present specification means an acid value measured according to JIS K2501.

The iodine value of the process oil is preferably 1.0 gI _2/100 g or less, more preferably 0.80 gI _2/100 g or less, still more preferably 0.50 gI _2/100 g or less, and particularly preferably 0.20 gI _2/100 g or less. be. The iodine value in the present specification means a viscosity index measured according to JIS K0070.

The initial distillation point (IBP) in gas chromatographic distillation of the process oil is preferably 300 ° C. or higher, more preferably 310 ° C. or higher, still more preferably 320 ° C. or higher, particularly preferably 330 ° C. or higher, and preferably 500 ° C. or higher. ° C. or lower, more preferably 490 ° C. or lower, still more preferably 480 ° C. or lower, and particularly preferably 470 ° C. or lower.

The 10% distillation temperature of the process oil in gas chromatographic distillation is preferably 300 ° C. or higher, more preferably 320 ° C. or higher, still more preferably 340 ° C. or higher, particularly preferably 360 ° C. or higher, and preferably 600 ° C. or higher. Below, it is more preferably 590 ° C. or lower, further preferably 580 ° C. or lower, and particularly preferably 570 ° C. or lower.

The initial distillate and 10% distilling temperature in the present specification are the initial distilling point and 10 (volume)% distilling measured according to the distillation test method by gas chromatography specified in ASTM D7213-05, respectively. Means temperature.

Since the process oil according to the present embodiment can have both weather resistance and bleed resistance, it is suitably used as a rubber softener in a rubber composition. That is, the rubber composition according to the present embodiment contains a rubber component and the process oil according to the present embodiment.

The rubber components include, for example, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), natural rubber (NR), butadiene rubber (BR), isoprene rubber (IR), and Shinji. It may be tacticic-1,2-polybutadiene, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, or the like.

The content of the process oil in the rubber composition may be 10 phr (mass part with respect to 100 parts by mass of the rubber component) or more, 15 phr or more, or 20 phr or more, and may be 50 phr or less, 40 phr or less, or 35 phr or less.

The rubber composition may further contain other components in addition to the rubber component and the process oil. Other components include organic acid metal salts such as cobalt organic acid, resins such as phenolic resins, vulcanizing agents such as sulfur, adhesives such as resorcinol, sulfenamide compounds, vulcanization accelerators such as thiuram compounds, and carbon. , Anti-aging agents, plasticizing agents, waxes, antioxidants, fillers, lubricants, UV absorbers, dispersants, compatibilizers, homogenizing agents and the like. The content of each of these components may be 5 phr or less, 3 phr or less, or 1 phr or less.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples.

In Examples and Comparative Examples, process oils having the properties shown in Tables 1 and 2 were used. The method for measuring each property of the process oil is as follows.
Kinematic viscosity, viscosity index: JIS K2283
VGC (Viscosity Specific Gravity Constant), Refractive Index Section (ri): ASTM _D2140
Absorbance: JIS K0115 (a sample obtained by diluting 2.0 g of process oil with 50 mL of hexane and a cell having a thickness of 10 mm were used.)
Aniline point: JIS K2256
Flash point (COC): JIS K2265-4 (Cthulhu Opening (COC) method)
Pour point: JIS K2269
Acid value: JIS K2501
Iodine value: JIS K0070
IBP (Initial Distillation Point), 10% Distillation Temperature: ASTM D7213-05

(Evaluation of weather resistance)
100 mL of each process oil having the properties shown in Tables 1 and 2 was placed in a glass bottle and exposed to direct sunlight outdoors for 50 days, and then the presence or absence of hue change of the process oil was visually confirmed. The results are shown in Tables 1 and 2.

(Preparation of rubber composition)
70 parts by mass of process oil having the properties shown in Tables 1 and 2, 3 parts by mass of cobalt naphthenate (manufactured by DIC Co., Ltd.), phenol resin (Sumitomo Bakelite Co., Ltd.) with respect to 100 parts by mass of EPDM (manufactured by JSR Co., Ltd., EP35) 1 part by mass of Sumilite Resin PR-12687), 0.5 part by mass of resorcinol (manufactured by Mitsui Chemicals, Inc., resorcin), 2.5 parts by mass of sulfur (manufactured by Hosoi Chemicals, Ltd., 200Mesh), sulfenamide 0.5 parts by mass of system vulcanization accelerator (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Noxeller CZ-G) and 1 mass of thiuram-based vulcanization accelerator (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Noxeller TOT-N) Each material was kneaded so as to form a part to obtain a rubber composition. In the kneading operation, first, the material excluding the vulcanizing agent is added to EPDM, kneaded with a Banbury mixer or a kneader (non-professional kneading), taken out from the kneader, cooled sufficiently, and then the vulcanizing agent is added. Then, it was returned to the kneading machine and kneaded (professional kneading).

(Evaluation of bleed resistance)
The obtained test pieces of each rubber composition were left at 90 ° C. in a 99% RH atmosphere for one week, and then the presence or absence of precipitates (bleeds) on the surface of each test piece was visually observed. The results are shown in Tables 1 and 2.

Claims (6)

The kinematic viscosity at 75 ° C. is 5 mm ² / s or more and 100 mm ² / s or less, the viscosity specific gravity constant is 0.700 or more and 0.900 or less, and the absorbance at 198 nm is more than 3 and 3.6 or less, and 228 nm. A process oil having an absorbance of 1.6 or more and 3.5 or less and an aniline point of 100 ° C. or more and 200 ° C. or less. The process oil according to claim 1, wherein the refractive index section is 1.040 or more and 1.050 or less. The process oil according to claim 1 or 2, wherein the 10% distillation temperature is 300 ° C. or higher and 600 ° C. or lower. The process oil according to any one of claims 1 to 3, wherein the iodine value is 1.0 gI _2/100 g or less. The process oil according to any one of claims 1 to 4, wherein the acid value is 0.10 mgKOH / g or less. A rubber composition containing a rubber component and the process oil according to any one of claims 1 to 5.