JP2002003861A - Process oil and high-viscosity base oil and their production methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel and highly economical process for producing a process oil which is highly safe and exhibits good penetration into a rubber polymer and contains a DMSO extract lower than 3%. SOLUTION: In a process for producing an extract useful as a process oil and a raffinate useful as a high-viscosity base oil by solvent purification, vacuum distillation is conducted under such conditions that the end point of the distillate in terms of normal pressure is 580 deg.C or higher or under such conditions that the initial boiling point of the residue is 450 deg.C or higher; the resultant residual oil is deasphalted under such conditions as to give a deasphalted oil having a residual carbon content of 1.6% or lower; and the deasphalted oil is subjected to solvent purification under such conditions that the extract yield is 35-60%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process oil and a high-viscosity base oil to be added to a natural rubber or a synthetic rubber, and a method for producing the same. The present invention relates to a rubber process oil which has no cancer and is easy to handle, and a method for producing the same.

[0002]

2. Description of the Related Art Rubber process oils are used to facilitate rubber production operations such as kneading, extrusion, molding, etc., by utilizing the permeability of a rubber polymer structure. It is also used to improve the physical properties of rubber products. Such a rubber process oil needs to have a suitable affinity for rubber. On the other hand, rubber to be processed includes natural rubber and synthetic rubber, and there are various types of synthetic rubber. Among these, in particular, natural rubber and styrene-butadiene rubber (SBR) are used in a large amount, and a rubber process oil containing a large amount of an aromatic hydrocarbon and having a high affinity for the rubber is generally used. Used.

In order to obtain such a rubber process oil,
After deasphalting the lubricating oil fraction obtained by vacuum distillation of crude oil, or the vacuum distillation residue, subject the oil obtained by dewaxing or hydrorefining to affinity with aromatic hydrocarbons as necessary. The oil obtained by extracting the oil with a solvent having the following formula is used. According to the column chromatography, the rubber process oil obtained in this way is 7
Ring analysis (ASTM D21) containing 0-99% aromatics
According If% _{C A} value of 40) is 20 to 50%, dimethyl sulfoxide (DMSO) 5 to 25 wt% containing an extract fraction corresponding to the content of specified by polycyclic aromatic compounds British Petroleum Institute (PCA) I do.

However, in recent years, the carcinogenicity of PCA has been regarded as important, and in Europe, oil containing 3% or more of DMSO extract is required to be toxic, and there is a movement to restrict its use. Therefore, there is an urgent need to reduce the amount of DMSO extracted from rubber process oil to less than 3%.

[0005] As for rubber process oils having a DMSO extractable content of less than 3%, Japanese Patent Publication No. 6-505524 discloses a deasphalting treatment of a vacuum distillation residue and a dewaxing treatment of the obtained oil to obtain a DMSO extractable product. Disclosed is a process for producing a rubber processing oil with a reduction of less than 3%. The above oils have lower DMSO extractables but higher aniline points. The aniline point is an index of the content of the aromatic hydrocarbon, and a high aniline point means that the content of the aromatic hydrocarbon is low. However, as the aromatic hydrocarbon content in the oil decreases,
The affinity of the oil for the rubber is reduced. Therefore, in the technology disclosed in the above publication, the properties required for the rubber process oil, that is, the permeability of the rubber process oil to the rubber polymer is reduced. Also, it is difficult to satisfy the physical condition of the final rubber product.

Further, Japanese Patent Publication No. 7-501346 discloses a non-carcinogenic bright stock extract and / or deasphalted oil and a process for purifying the same, in order to reduce the mutagenicity index (MI) to 1 or less. Proposes that a property correlated with MI be used as an index for purification. In this case, oil obtained by deasphalting the residue in a vacuum distillation column or oil whose aromatic compounds have been reduced by extraction of deasphalted oil or oil obtained by dewaxing the oil is used. However, the DMSO extract is estimated to be 3% or more. The relationship between MI and DMSO extract of such deasphalted oil is not disclosed in the patent.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve such problems of the prior art, and it is an object of the present invention to provide a highly safe and highly permeable DMSO polymer. An object of the present invention is to provide a new and economical process for producing a rubber processing oil having an extractable amount of less than 3%.

[0008]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies and as a result, have found that a specific distillation /
It has been found that the amount of DMSO extractables under solvent purification conditions is less than 3%, and the present invention has been achieved.

The present invention based on the above findings provides: In the process of producing an extract useful as a process oil and a raffinate useful as a high-viscosity base oil by solvent refining, the end point of the distillate is reduced to atmospheric pressure at 580 ° C.
Under the above conditions or under the condition that the initial distillation of the residue is 450 ° C. or more, the obtained residual oil is deasphalted under the condition that the residual carbon content of the deasphalted oil is 1.6% or less. By subjecting it to a solvent purification to obtain an extract yield of 35 to 60%.

[0010] 2. Useful extract as a process oil, 100 ° C. kinematic viscosity _{^{50~100mm 2 / s,% C A}} 1
5-35%, DMSO extractables (IP346) less than 3%,
The production method according to the above 1, wherein the aniline point is 90 ° C. or less, the aromatic content by chromatography is 60% to 95% by weight, and the Mw (weight average molecular weight) is 650 or more;

3. 40 obtained after dewaxing of the raffinate
Kinematic viscosity of 400mm²/ s more than 700mm ²Higher than / s
The pour point of the base oil is -5 ° C or less, and the viscosity index is 95 or more.
The manufacturing method according to 1 above,

4. Kinematic viscosity at 100 ° C. 50 to 100 mm ² /
_{s,% C A 15~35%,} DMSO extractables (IP34
6) a process oil characterized by having an aniline point of 90 ° C. or less, an aromatic content of 60 to 95% by weight, and a Mw (weight average molecular weight) of 650 or more,

5. The process oil according to the above 4, wherein the mutagenicity index MI is less than 1.0.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Process oils can generally be prepared starting from a lubricating oil fraction obtained from crude oil. The lubricating oil fraction can be obtained as a fraction obtained by distilling the residual oil after the crude oil is distilled under normal pressure, or as a deasphalted oil obtained by deasphalting the residual oil obtained by distilling the crude oil under reduced pressure. Solvent extraction is a method of separating each component from the lubricating oil fraction. In the solvent extraction of oil, if a solvent having a selective affinity for aromatic hydrocarbon compounds is used, aromatic hydrocarbons are separated from the lubricating oil fraction. can do. However, since a solvent having a selective affinity for an aromatic hydrocarbon compound has a higher affinity for a polycyclic aromatic compound (PCA), a large amount of the aromatic hydrocarbon compound is extracted by a general extraction operation. PCA will be included. PC from this extracted oil
If A can be removed, a suitable process oil is obtained, but is generally difficult and not economical. The present inventors have studied an oil production process with a small amount of PCA and found that the oil can be effectively produced by combining specific vacuum distillation conditions and solvent purification conditions.

The process for producing a rubber process oil according to the present invention is characterized in that a deasphalted oil fraction obtained by deasphalting a distillation residue obtained from crude oil by vacuum distillation is treated with a solvent having an affinity for aromatic hydrocarbons. This is to separate and recover the solvent and the extract (extract). In this case, the raffinate separated at the time of solvent extraction can be subjected to a hydrogenation treatment and a dewaxing treatment as necessary, and can be used as a high-viscosity base oil.

The process oil obtained by the specific production method of the present invention is most suitable as a rubber process oil having a low polycyclic aromatic compound content and a high aromatic hydrocarbon content. The DMSO extract used in the present application is obtained by a DM method according to the IP346 method specified by the British Petroleum Institute.
It refers to the content of aromatic compounds extracted by SO (dimethyl sulfoxide). Some of the conventional PCA regulations refer to aromatic compounds having three or more rings.
Method 46 is a general and standard method recognized as a method for determining the PCA content of oil materials.

The rubber processing oil obtained by the present invention has a very low content of polycyclic aromatic compounds, but the aromatic hydrocarbon content measured by chromatography is hardly reduced as compared with the conventional rubber processing oil. Therefore, the permeability to rubber such as SBR rubber and natural rubber is high, and the workability of rubber does not decrease. In addition, the rubber process oil of the present invention is a sufficient material to obtain a rubber capable of exhibiting almost the same physical properties as a rubber product obtained by treating with a conventional process oil containing a large amount of PCA. .

Hereinafter, embodiments of the manufacturing method of the present invention will be described in detail. In order to produce the rubber process oil of the present invention, the deasphalted oil fraction obtained by deasphalting the vacuum distillation residue obtained by subjecting the atmospheric distillation residue of crude oil to vacuum distillation under predetermined conditions,
The extract is obtained in the form of a mixture with a solvent by treating with a solvent having a selective affinity for aromatic hydrocarbons and removing the raffinate. By removing this solvent, a rubber process oil is obtained.

As the crude oil, various crude oils such as paraffin crude oil, naphthenic crude oil and the like can be used, and deasphalted oil obtained by deasphalting the vacuum distillation residue obtained by vacuum distillation of the atmospheric distillation residue of any kind of crude oil. Can be used.

In the vacuum distillation, the end point of the distillate is 58
The reaction is performed under the condition of 0 ° C. or higher or the condition of the first residue of 450 ° C. or higher. If the end point is lower than this temperature, the amount of DMSO extracted from the obtained extract is undesirably high.

Next, the residual oil obtained by the vacuum distillation is deasphalted under the condition that the residual carbon content of the deasphalted oil is 1.6% or less. If the residual carbon content exceeds 1.6%, PC in the extract
A is not preferred because it increases A and adversely affects the oxidation stability of the resulting high-viscosity base oil.

The deasphalted oil obtained by the above method is subjected to a solvent refining treatment for extracting with a solvent having an affinity for aromatic hydrocarbons. As the solvent having a selective affinity for the aromatic hydrocarbon, one or more selected from furfural, phenol and N-methyl-2-pyrrolidone can be used.

This solvent refining step is carried out under the condition that the extract yield is 35 to 60%. Under the condition that the extract yield is less than 35%, the DMSO extractable content is not less than 3%, while the extract yield is less than 60%.
%, The aromatic content in the extract is decreased, and the yield of the high-viscosity base oil obtained as a raffinate is lowered, which is not preferable because the economic efficiency is deteriorated.

Specific extraction conditions for keeping the extract yield within the above range cannot be uniquely determined because it depends on the deasphalted oil composition, but it should be adjusted according to the solvent ratio, pressure, temperature and the like. Is possible. Generally, a temperature of 6
The mixture is brought into contact with a solvent at a temperature of 0 ° C. or more, preferably 60 to 155 ° C., at a solvent / oil ratio (volume ratio) of about 2/1 to 7/1 to remove the raffinate. This raffinate can be used as a high-viscosity lubricating base oil by further performing a hydrotreating / dewaxing step as required.

The extract useful as a process oil in the present invention has a kinematic viscosity at 100 ° C. of 50 to 100 mm ² /
s,% C _A (ASTM D2140) 15-35%, D
MSO extractables (IP346) less than 3%, aniline point 90
C. or lower, aromatic content by weight of 60 to 95% by weight, and Mw (weight average molecular weight) of 650 or more. In addition, it has a mutagenicity index MI of less than 1.0.

When the kinematic viscosity at 100 ° C. exceeds 100 mm ² / s, the workability when used as a process oil decreases, and the effect of lowering the viscosity of rubber as a process oil becomes insufficient. On the other hand, the kinematic viscosity at 100 ° C. is 50 mm ² / s
If the amount is less than 3%, it is extremely difficult to reduce the DMSO extractable amount to less than 3%, and the economical efficiency of the purification step is deteriorated.

If the% C _A (ASTM D2140) is less than 15%, it may be difficult to produce a rubber using a rubber process oil or the physical properties of a rubber product may be deteriorated. On the other hand,% C _A (ASTM D2140)
If it exceeds 35%, the physical properties of the rubber product may be deteriorated, and it is extremely difficult to reduce the amount of DMSO extractable to less than 3%.

As described above, the DMSO extract (IP346) is set to be less than 3% because if it exceeds 3%, there is a risk of carcinogenicity and it is subject to EU regulation.

If the aniline point exceeds 90 ° C., the compatibility with the rubber decreases, which is not preferable.

Further, when the aromatic content by chromatography is less than 60%, it may be difficult to produce a rubber using a rubber process oil or the physical properties of a rubber product may be deteriorated. On the other hand, if the aromatic content by chromatography exceeds 95%, the physical properties of the rubber product may still deteriorate, and it is extremely difficult to reduce the DMSO extractable content to less than 3%. Is not preferred because it becomes worse.

If the Mw (weight average molecular weight) is less than 650, it is also extremely difficult to make the DMSO extractable amount less than 3%, and the economics of the purification step is unfavorably deteriorated. A mutagenicity index MI of 1.0 or more is not preferred because of the possibility of carcinogenicity.

Further, the glass transition point measured by DSC is -70% because the performance of imparting a low loss to rubber products is improved.
C. or higher is preferred. In addition, the temperature is preferably -20 ° C or lower from the viewpoint of low-temperature performance.

The raffinate obtained by the solvent refining step may be further subjected to a hydrogenation / dewaxing step, if necessary, to obtain a pour point of -5 ° C. or less, a viscosity index of 95 or more, and a kinematic viscosity (40 ° C.) of 400 mm ² / A high-viscosity base oil having a viscosity of s to 700 mm ² / s can be obtained.

When the production method of the present invention is used, an extract obtained by one-stage solvent extraction can be directly used as a product, and therefore, a method of performing a two-stage solvent extraction or a secondary treatment such as hydrogenation treatment The manufacturing cost is reduced as compared with the case. In addition, since a non-carcinogenic process oil and a high-viscosity base oil having a viscosity index higher than usual can be obtained at the same time, it is excellent in economical efficiency.

[0035]

The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the examples. The measurement items in the present invention were determined by the following methods.

[Polycyclic aromatic compound (PCA) concentration (DM
Measurement of SO Extract) DMSO extract is IP346
(1992 edition) Determined by the test method.

[0037] [Ring Analysis ring analysis% _{C A} is, ASTM
D 2140-97.

[Kinematic viscosity] JIS K2283-1993
The measurement was carried out according to the above-mentioned rules.

[Aniline point] JIS K2256-19
The measurement was carried out in accordance with the 98 standard.

[Mw (weight average molecular weight)]
It is defined by ΣMi ² Ni / ΣMiNi (Mi: molecular weight, Ni: number of molecules), and is generally measured by GPC (gel permeation chromatography) or the like. This time, Mw (in terms of polystyrene) was measured by GPC under the following conditions. Solvent: tetrahydrofuran Column temperature: 50 ° C. Flow rate: 1.0 ml / Min Column: Shodex GPC KF-805L Detector: Shimadzu RID-6A

[Pour point] JIS C2101-1999
The measurement was carried out according to the above-mentioned rules.

[Viscosity index] JIS K2283-199
Calculated according to the rules of 3.

[Nitrogen content] JIS K2609-1998
Calculated according to the regulations.

[Sulfur content] JIS K2541-1996
The measurement was carried out according to the above-mentioned rules.

[Aromatic Content by Chromatography] ASTM D
It measured according to the regulation of 2007-98.

[Mutagenicity Index (MI)] ASTM E1
687-98.

[Gas chromatography distillation] ASTM D2887-
It was measured according to the provisions of 97a.

[Residual carbon content] JIS K2270-19
The measurement was carried out in accordance with the 98 standard.

Example 1 Arabian light crude oil was distilled under reduced pressure so that the end point was (gas chromatography distilled FBP) at 600 ° C., and the residue was subjected to propane deasphalting so that the residual carbon content was 1.3%. (Solvent ratio is 700%, pressure is 3.3
MPaG, reaction tower 72 ° C.), using furfural as a solvent, the solvent ratio was 400%, and the extract yield was 42%.
Solvent extraction was performed so that Raffinate is hydrorefined (hydrogen pressure: 6.5) using an alumina-based catalyst further supporting 3% by weight of nickel and 12% by weight of molybdenum.
MpaG, liquid hourly space velocity (LHSV): 2.5 h ^-1 , temperature: 315 ° C., desulfurization rate 48%), and after removing light components, solvent dewaxing (methyl ethyl ketone: toluene = 1: 1)
1, 330% solvent ratio, cooled to -20 ° C, 84% yield)
Kinematic viscosity (40 ° C.) 508.4 mm ² / s, pour point −
A high viscosity base oil having a viscosity index of 101 was obtained at 10 ° C. IP34
DMSO extractables measured extract by 6 method 2.7 wt.%,% _{C A} is 25.3%, a kinematic viscosity (100
° C) was 65.26 mm ² / s, the aniline point was 72 ° C, the aromatic content by chromatography was 84% by weight, and the Mw was 785.

(Comparative Example 1) Arabian light crude oil was distilled under reduced pressure so that the end point was (gas chromatography distilled FBP) 600 ° C., and the remaining residue was deasphalted with propane so that the residual carbon content was 1.3%. (Solvent ratio is 700%, pressure is 3.3
MPa, reaction tower temperature 72 ° C.), using furfural as a solvent to a solvent ratio of 350%, and an extract yield of 3
Solvent extraction was performed so as to be 0%. The DMSO extract of the extract measured by the IP346 method was 4.0.
Wt%% _{C A} is 28.6%, a kinematic viscosity (100 ° C.) is 8
0.24 mm ² / s, the aniline point was 63 ° C., the aromatic content by chromatography was 86% by weight, and Mw was 730.

Comparative Example 2 Arabian light crude oil was distilled under reduced pressure so that the end point was (gas chromatography distilled FBP) 600 ° C., and the residue was propane deasphalted so that the residual carbon content was 1.3%. (Solvent ratio is 700%, pressure is 3.3
MPaG, reaction tower 72 ° C.), using furfural as a solvent, the solvent ratio was 280%, and the extract yield was 20%.
Solvent extraction was performed so that DMSO extractables measured extract by IP346 method 5.3 wt.%,% _{C A} is 33.5%, a kinematic viscosity (100 ° C.) is 110.
6 mm ² / s, aniline point 51 ° C., aromatic content by chromatography is 86 wt%, Mw was 645.

Comparative Example 3 Arabian light crude oil was distilled under reduced pressure so that the distillation point was (gas chromatography distilled FBP) 560 ° C., and the remaining residue was propane-desorbed so that the residual carbon content was 1.3%. Asphalt (solvent ratio 700%, pressure 3.3
MPaG, reaction tower 72 ° C.), using furfural as a solvent, the solvent ratio was 280%, and the extract yield was 25%.
Solvent extraction was performed so that DMSO extractables measured extract by IP346 method 9.9 wt.%,% _{C A} is 33.6%, a kinematic viscosity (100 ° C.) 58.3
The aniline point was 3 mm ² / s, the aromatic content by chromatography was 86% by weight, and the Mw was 601.

Table 1 shows the solvent refining conditions of Examples and Comparative Examples, and the properties of the high-viscosity base oil obtained by solvent dewaxing of the obtained extract and raffinate.

[0054]

[Table 1]

[0055]

As described above, according to the production method of the present invention, a process oil having high safety and high permeability to a rubber polymer and a high-viscosity base oil can be simultaneously and economically obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C10N 20:04 C10N 20:04 30:02 30:02 70:00 70:00

Claims (5)

[Claims] In a process for producing an extract useful as a process oil and a raffinate useful as a high-viscosity base oil by solvent refining, vacuum distillation is carried out under conditions in which the end point of the distillate is 580 ° C. or more in terms of atmospheric pressure or residue. First stay at 450
The deasphalted oil is subjected to deasphalting under the condition that the residual carbon content of the deasphalted oil is 1.6% or less, and the deasphalted oil is subjected to solvent purification to reduce the extract yield. 35-6
A production method characterized by being obtained by performing the reaction under a condition of 0%. 2. An extract useful as a process oil has a kinematic viscosity at 100 ° C. of 50 to 100 mm ² / s,% C _A 15
2. The method according to claim 1, wherein the content of DMSO extractables (IP346) is less than 3%, the aniline point is 90 ° C. or less, the aromatic content is 60% by weight to 95% by weight, and the Mw (weight average molecular weight) is 650 or more. . 3. 40 ° C. obtained after dewaxing of the raffinate
Kinematic viscosity 400 mm ^{2 /} s or more 700mm pour point of the high-viscosity base oil is ^{2 /} s or less -5 ° C. or less, The method according to claim 1 viscosity index of 95 or more. 4. A kinematic viscosity at 100 ° C. of 50 to 100 mm ² / s,
% _C A 15~35%, DMSO extractables (IP346) 3
A process oil having an aniline point of 90 ° C. or less, an aromatic content of 60% by weight to 95% by weight, and an Mw (weight average molecular weight) of 650 or more. 5. The process oil according to claim 4, wherein the mutagenicity index MI is less than 1.