JP2017211437A - Microscope immersion oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microscope immersion oil which satisfies properties required as a microscope immersion oil such as a refractive index, Abbe number, kinetic viscosity, and resolving power, is less fluorescent compared with conventional microscope immersion oils, and stably exhibits the low fluorescence property regardless of manufacturing lots of diarylalkane.SOLUTION: A microscope immersion oil contains (A) a liquid olefin polymer, (B) a liquid diene polymer, (C) diarylalkane that has gone through at least one pretreatment selected from an absorption treatment, distillation treatment, or heat treatment, and (D) alkyl benzene.SELECTED DRAWING: None

Description

  The present invention relates to an immersion oil for microscopes, and more specifically, an immersion oil for microscopes that can maintain low fluorescence over a long period of time and can be stably produced, In particular, the present invention relates to an immersion oil suitable for a fluorescent microscope.

Conventionally, immersion oil is very commonly used in the field of microscopy. When immersion oil is used, not only substantially no surface aberration is obtained, but also the magnification of the microscope can be increased by increasing the numerical aperture of the objective lens as compared with the case where immersion oil is not used.
Immersion oil used in this case is composed of a diarylalkane compound, a specific naphthalene compound and a specific diphenyl compound (see, for example, Patent Document 1), and is composed of benzylbutyl phthalate and chlorinated paraffin (for example, a patent) 2), an immersion oil for microscopes containing a tricyclodecane derivative or a derivative of a substance having a basic structure of tricyclodecane as a main component (see, for example, Patent Document 3), an ether bond to liquid polybutene (liquid polybutylene). Microscopic immersion oil blended with a liquid aromatic compound (see, for example, Patent Document 4), immersion oil blended with a liquid polyolefin and an aromatic compound (see, for example, Patent Document 5), norbornanes, and Immersion oils for microscopes containing norbornene monomers to tetramer hydrogenates (for example, patent documents) Microscope immersion oil (for example, refer to Patent Document 7) in which a phthalate ester and paraffins are blended with a liquid diene copolymer, and a microscope in which an α-olefin is blended with a liquid diene copolymer. Liquid immersion oil (see, for example, Patent Document 8) is known.
However, these immersion oils have almost all the properties required for microscope immersion oils, such as refractive index, Abbe number, viscosity, and resolving power, but their low fluorescence persistence when measured with a spectrophotometer. Not enough in terms of sex.

In general, a fluorescence microscope used for observing an object that emits fluorescence irradiates an examination object with excitation light such as ultraviolet rays and observes fluorescence emitted by the examination object, and is used in a wide field such as biology. . In particular, recently, a fluorescence microscope technique for detecting a very small amount of fluorescence has been studied, and when detecting such very weak fluorescence, the immersion oil used in the optical system of the fluorescence microscope is emitted by ultraviolet excitation. When the fluorescence is large, it becomes noise at the time of detection and the detection accuracy is lowered. Although improvement research on immersion oil has been conducted in this regard, as described above, the recent needs for further low fluorescence and stable low fluorescence of immersion oil are required. Was not satisfied with.
As a technique for improving the persistence of low fluorescence, immersion oil (Patent Document 9 and Patent Document 10) containing an olefin polymer, a liquid diene polymer, a diarylalkane, and an alkylbenzene has been developed.

Japanese Patent No. 2623125 U.S. Pat. No. 4,465,621 JP-A-9-241214 Japanese Patent Laid-Open No. 11-160623 JP-A-11-269317 International Publication No. 2004/090602 JP 2004-240245 A JP 2004-240246 A JP 2008-038001 A JP 2013-24925 A

When the present inventors further examined the immersion oil disclosed in Patent Documents 9 and 10, when the diarylalkane to be blended was obtained industrially, the cause is unknown, but depending on the production lot, the immersion oil From the viewpoint of stable production, it has been found that there is room for further improvement.
Therefore, the object of the present invention is to satisfy various properties required for a microscope immersion oil such as refractive index, Abbe number, kinematic viscosity, and resolving power, and is an immersion liquid with lower fluorescence than conventional microscope immersion oils. It is an object of the present invention to provide an immersion oil for microscopes that stably exhibits low fluorescence without being affected by the production lot of diarylalkane.

As a result of intensive investigations in view of the above situation, the present inventors have found that a microscopic immersion oil comprising a diarylalkane subjected to a specific pretreatment, a liquid polyolefin polymer, a liquid diene polymer, and an alkylbenzene. Then, it discovered that the said subject could be solved. The present invention has been completed based on such findings.
That is, the present invention relates to the following [1] to [12].
[1] (A) liquid olefin polymer, (B) liquid diene polymer, (C) diarylalkane subjected to at least one pretreatment selected from the group consisting of adsorption treatment, distillation treatment and heat treatment, And (D) an immersion oil for microscopes comprising alkylbenzene.
[2] The immersion oil for a microscope according to the above [1], wherein the (C) diarylalkane is the pretreated phenylxylylethane and / or the pretreated phenylethylphenylethane.
[3] The immersion oil for microscopes according to the above [1] or [2], wherein the pretreatment is a distillation treatment.
[4] The immersion oil for a microscope according to the above [1] or [2], wherein the pretreatment is an adsorption treatment selected from a clay treatment or an ion exchange resin treatment.
[5] (B) 1 to 30 parts by mass of liquid diene polymer, (C) 40 to 80 parts by mass of diarylalkane, and (D) alkylbenzene with respect to 100 parts by mass of (A) liquid olefin polymer. The immersion oil for a microscope according to any one of the above [1] to [4], comprising 2 to 30 parts by mass.
[6] The immersion oil for microscopes according to any one of [1] to [5] above, wherein the number average molecular weight of the (A) liquid olefin polymer is 300 to 25,000.
[7] The immersion oil for microscopes according to any one of the above [1] to [6], wherein the (A) liquid olefin polymer is polybutene.
[8] The immersion oil for microscopes according to any one of [1] to [7], wherein the (A) liquid olefin polymer is a hydrogenated liquid olefin polymer. .
[9] The immersion oil for microscopes according to any one of [1] to [8] above, wherein the number average molecular weight of the (B) liquid diene polymer is 1,000 to 100,000.
[10] The immersion oil for microscopes according to any one of the above [1] to [9], wherein the (B) liquid diene polymer is polyisoprene.
[11] The immersion oil for a microscope according to any one of the above [1] to [10], wherein the (D) alkylbenzene is 1,3,5-triisopropylbenzene.
[12] The immersion oil for a microscope according to any one of the above [1] to [11], which is an immersion oil for a fluorescence microscope.

  The microscope immersion oil of the present invention stably exhibits low fluorescence without being affected by the production lot of the raw material, and is further required as a microscope immersion oil for refractive index, Abbe number, kinematic viscosity, resolving power, etc. Other characteristics are highly maintained. Moreover, since the storage stability is good, low fluorescence is maintained over a long period of time. Therefore, the immersion oil for microscopes of the present invention is remarkably excellent as an immersion oil for fluorescent microscopes.

The immersion oil for microscope of the present invention is at least one selected from the group consisting of (A) liquid olefin polymer, (B) liquid diene polymer, (C) adsorption treatment, distillation treatment and heat treatment. It includes a treated diarylalkane and (D) alkylbenzene.
Hereafter, each component which the microscope immersion oil of this invention contains is demonstrated in order.

((A) Liquid olefin polymer)
The liquid olefin polymer of the component (A) used in the present invention is not particularly limited, but a liquid olefin polymer having a number average molecular weight of preferably 300 to 25,000, more preferably 500 to 5,000. Coalescence is used. These liquid olefin-based polymers include polyethylene, polypropylene, polybutene, polyisobutylene, etc., but polybutene is preferred. These liquid olefin polymers may be used singly or in a blend of two or more, or may be a copolymer thereof.
In the present specification, the number average molecular weight is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

  (A) There is no restriction | limiting in particular in the manufacturing method of a liquid olefin type polymer, It can manufacture by a well-known method and all are easily available industrially. For example, as a method for producing polybutene, there may be mentioned a method in which butadiene is removed from a C4 fraction produced by naphtha decomposition and polymerization is carried out using an acid catalyst as it is.

(A) As a liquid olefin polymer, the olefin polymer which performed the hydrogenation process is preferable. By performing this treatment, the fluorescence derived from the liquid olefin polymer (A) in the immersion oil for microscope can be stably reduced in fluorescence. In this case, regardless of whether the hydrogenation rate is high or low, it is possible to stably achieve low fluorescence.
There is no restriction | limiting in particular as a method of a hydrogenation process, The well-known hydrogenation process with respect to an olefin polymer can be utilized. Specifically, a method of performing a hydrogenation treatment in the presence of a hydrogenation catalyst, hydrogen, and, if necessary, a solvent can be mentioned.

  Examples of the hydrogenation catalyst include nickel-based (Raney nickel, nickel-supported) catalysts, noble metal-based materials such as palladium and platinum (palladium black, palladium hydroxide, platinum oxide, palladium-supported, platinum-supported, rhenium-supported, ruthenium. (Supported) catalyst. Examples of the supported catalyst carrier include activated carbon, alumina, silica alumina, silica, diatomaceous earth, and activated clay. Among these, palladium carbon, nickel diatomaceous earth, and ruthenium carbon are preferable from the viewpoint of hydrogenation effect, that is, the effect of stably obtaining a lower fluorescence immersion oil for microscope.

  Although there is no restriction | limiting in particular in the usage-amount of a hydrogenation catalyst, Preferably it is 0.1-50 mass parts with respect to 100 mass parts of olefin polymers which are going to perform a hydrogenation process, More preferably, it is 0.5-10 masses. Parts, more preferably 1 to 10 parts by mass, particularly preferably 1 to 5 parts by mass.

Although there is no restriction | limiting in particular in hydrogenation processing temperature, From a viewpoint of controlling hydrogenation reaction, Preferably it is about 0-200 degreeC normally, More preferably, it is 20-180 degreeC, More preferably, it is 50-160 degreeC, Most preferably, it is 70. ~ 140 ° C. The hydrogen pressure (the hydrogen pressure immediately before the hydrogenation treatment, hereinafter referred to as “initial hydrogen pressure”) is preferably about 0.01 to 10 MPa, more preferably 0.1 to 5 MPa, and still more preferably 0. .1-3 MPa.
Although there is no restriction | limiting in particular in hydrogenation processing time, Usually, Preferably it is about 1 minute-24 hours, More preferably, it is 5 minutes-10 hours, More preferably, it is 10 minutes-4 hours.

  The solvent that can be used as needed during the hydrogenation treatment is not particularly limited as long as it is an inert solvent for the hydrogenation reaction. For example, n-pentane, n-hexane, methylpentane, n-heptane. Linear or branched aliphatic hydrocarbons having 5 to 10 carbon atoms such as methylhexane, dimethylpentane, n-octane, methylheptane, dimethylhexane, trimethylpentane, dimethylheptane, n-decane, etc .; C5-C10 alicyclic compounds such as methylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, propylcyclohexane; methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, n- Heptanol, 2-he Ethanol, n- hexanol, etc. monoalcohols such as 2-hexanol. Among these, n-hexane, n-heptane, cyclohexane, methylcyclohexane, ethylcyclohexane, and n-butanol are preferable for the convenience of the hydrogenation treatment.

(Liquid diene polymer of component (B))
Although there is no restriction | limiting in particular as a liquid diene type polymer of (B) component used for this invention, The number average molecular weight of polystyrene conversion measured by the gel permeation chromatography (GPC) method becomes like this. 100,000, more preferably 1,000 to 80,000 liquid diene polymer is used.
Examples of these liquid diene polymers include a diene homopolymer composed of a diene monomer having 4 to 12 carbon atoms, a diene copolymer composed of two or more diene monomers having 4 to 12 carbon atoms, and these diene monomers and carbon numbers. Examples include copolymers with 2 to 22 α-olefin addition polymerizable monomers. Examples include butadiene homopolymer (liquid polybutadiene, hydroxyl group-containing liquid polybutadiene), isoprene homopolymer (hydroxyl group-containing liquid polyisoprene), chloroprene homopolymer, butadiene-isoprene copolymer, butadiene-acrylonitrile copolymer, butadiene-2-hexyl acrylate copolymer, and the like. It is done.

Preferred liquid diene polymers are butadiene homopolymers such as liquid polybutadiene and hydroxyl group-containing liquid polybutadiene, isoprene homopolymers such as hydroxyl group-containing liquid polyisoprene, and copolymers comprising polybutene and polyisoprene, more preferably polyisoprene. . The liquid diene polymer may have a functional group such as a hydroxyl group in the molecule and / or at the molecular end. Alternatively, it may be a mixture with a liquid diene polymer having no functional group. These liquid diene polymers may be used singly or in combination of two or more.
Moreover, after pretreating the liquid diene polymer of component (B), it may be used as one component of immersion oil for microscopes of the present invention. Examples of the pretreatment include adsorption treatment and heat treatment. It is also possible to perform a combination of these pretreatments.

((C) Diarylalkane subjected to at least one pretreatment of adsorption treatment, distillation treatment or heat treatment)
The component (C) used in the present invention is a diarylalkane subjected to at least one pretreatment selected from the group consisting of adsorption treatment, distillation treatment and heat treatment. By using a diarylalkane subjected to such pretreatment, it is possible to provide an immersion oil for a microscope that stably exhibits low fluorescence without being affected by the production lot of the diarylalkane. The reason why such an effect is obtained is not clear, but industrially obtained diarylalkanes generate impurities due to subtle differences in production conditions, and the impurities are the other (A) component, (B) component and ( It is presumed that the low fluorescence is deteriorated in the presence of component D). Hereinafter, the diarylalkane and a method for pretreating it will be described.

<Diarylalkane>
The diarylalkane used in the present invention is not particularly limited as long as it is a diarylalkane that is liquid at normal temperature and normal pressure or a mixed diarylalkane that is liquid at normal temperature and normal pressure. Each of the two aryl groups of the diarylalkane is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 10 carbon atoms, and 1 to 10 carbon atoms, preferably 1 to 1 carbon atoms. 5 alkyl groups may be substituted. Further, the “alkane” portion of the diarylalkane preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 5 carbon atoms, and particularly preferably carbon. It is an alkane of formulas 1-3.

Examples of the diarylalkane include diphenylmethane, benzyltoluene, benzylxylene, phenyl-sec-butylphenylmethane, di-sec-butyldiphenylmethane, diphenylethane, phenylethylphenylethane, phenylcumylethane, diisopropylphenylethane, phenyltolylethane, Examples include di-sec-butylphenylethane, di-tert-butylphenylethane, phenylxylylethane, phenyl-sec-butylphenylethane, diphenylpropane, diphenylbutane, ditolylethane, dixyloctane, and dixylyldecane. Of these, phenylethylphenylethane and phenylxylylethane are preferred.
Examples of phenylethylphenylethane include 1-phenyl-1- (2-ethylphenyl) ethane, 1-phenyl-1- (3-ethylphenyl) ethane, 1-phenyl-1- (4-ethylphenyl) ethane, 1 -Phenyl-2- (2-ethylphenyl) ethane and the like can be mentioned.
Examples of phenylxylylethane include 1-phenyl-1- (2,3-dimethylphenyl) ethane, 1-phenyl-1- (2,4-dimethylphenyl) ethane, 1-phenyl-1- (2,5- Dimethylphenyl) ethane, 1-phenyl-1- (2,6-dimethylphenyl) ethane, 1-phenyl-1- (3,4-dimethylphenyl) ethane, 1-phenyl-1- (3,5-dimethylphenyl) ) Ethane, 1-phenyl-2- (2,3-dimethylphenyl) ethane and the like.
These diarylalkanes can be used either individually or as a mixture of two or more as long as they are liquid at normal temperature and pressure.

<Preprocessing>
The diarylalkane pretreatment is at least one treatment selected from the group consisting of adsorption treatment, distillation and heat treatment. It is also possible to perform a combination of these processes.

Adsorption treatment agents that can be used for the adsorption treatment include silica, alumina, activated clay, activated carbon, ion exchange resin, zeolite, and the like. In addition, the adsorption processing agent to be used may be used independently and 2 or more types may be used.
The silica is not particularly limited, but amorphous silica, crystalline silica, silica hydrate, or the like can be used. Examples of commercially available products include silica gel (manufactured by Organo Corporation, “FS-0012”).
The alumina is not particularly limited, but amorphous alumina, crystalline alumina, alumina hydrate, and the like can be used. Examples of commercially available products include activated alumina (manufactured by Sumitomo Chemical Co., Ltd., “NKHO-24”).
The activated clay is not particularly limited, but a naturally produced acidic clay treated with sulfuric acid is used. However, it may be used after removing the adsorbed moisture by drying before use. Examples of commercially available products include activated clay (“Galleon Earth NS” manufactured by Mizusawa Chemical Industry Co., Ltd.).

  Although it does not restrict | limit in particular about activated carbon, vegetable type, calcareous type, and petroleum type activated carbon can be used. In particular, calcareous activated carbon made from vegetal materials made from wood, charcoal, coconut shell charcoal, bituminous coal, lignite, etc. is preferably used. Examples of commercially available products include “Shirakaba A” manufactured by Nippon Enviro Chemicals Co., Ltd. as activated carbon.

  The ion exchange resin is not particularly limited, and commercially available ones can be used. However, after replacing with a solvent such as methanol in advance, water contained in the resin is obtained by vacuum heating and drying. It is preferable to remove it. Examples of commercially available products include ion exchange resins (such as “Amberlist 15” and “Amberlist 16” manufactured by Rohm and Haas), “K2441”, “K2461”, “K2661” manufactured by Bayer, and the like, manufactured by Dow Chemical "Dowex 88", "Dowex MSC-1", etc.).

  The zeolite is not particularly limited, but a zeolite such as a faujasite type, a shabasite type, or a mordenite type can be used. Examples of the faujasite type zeolite include natural zeolite such as faujasite, A type zeolite such as 3A, 4A and 5A, X type zeolite such as 10X and 13X, and synthetic zeolite such as Y type. These zeolites can also be used in combination. Examples of the shabasite-type zeolite include natural zeolites such as shabasite, gmelinite, erionite, and levinite, and R-type, S-type, and T-type synthetic zeolite. Examples of the mordenite-type zeolite include natural or synthetic mordenite and clinoptilolite. The zeolite can be used as a natural product or an artificial synthetic product, but an artificial synthetic product having a stable quality is preferable. In synthetic zeolite, it is also possible to change the pore distribution, the Si / Al ratio, and the content of other metals by changing the formulation.

  Further, in the pretreatment, zeolite modified by calcination, acid contact, base contact, ion exchange or the like can be used regardless of natural zeolite or synthetic zeolite. Ions suitable for ion exchange are alkali metal ions or alkaline earth metal ions. Examples of alkali metal ions include lithium ions, sodium ions, potassium ions, rubidium ions, and cesium ions. Examples of the alkaline earth metal ions include beryllium ions, magnesium ions, calcium ions, strontium ions, and barium ions.

  The shape of the adsorbent is not particularly limited, and may be any shape. The amount of the adsorbent used depends on the content of impurities in the compound before treatment, but is 0.01 to 10 g, preferably 0.05 to 1 g, relative to 1 g of compound before treatment.

  The temperature at which the compound solution is treated with the adsorbent is usually 0 to 100 ° C, but preferably 10 to 40 ° C.

  The time for treating the compound solution with the adsorbent is usually several minutes to several hours, but preferably several tens of minutes to several hours.

As a method of treating a compound solution with an adsorbent, a predetermined amount of adsorbent is added to the compound solution and the whole volume is stirred for a predetermined time. The compound solution is passed through a column packed with the adsorbent. And the like.

As a method for pretreating the diarylalkane by distillation, a known method can be selected. Examples thereof include simple distillation, steam distillation, continuous multistage distillation, batch multistage distillation, and continuous rectification using a packed column.
The distillation is preferably performed under reduced pressure, and the reflux ratio (reflux / distillation) is preferably 1/10 or more (the reflux is 1 or more with respect to the distillate of 10). More preferably, it is 5 to 1/2.
This distillation may be carried out alone, or two or more diarylalkanes may be combined and distilled simultaneously.

In the case of heat treatment of diarylalkane, the time for heat treatment of the compound solution is usually from several hours to several days, depending on the temperature, but preferably 1 to 2 days. The temperature at which the compound solution is heat-treated is usually 50 to 100 ° C, preferably 60 to 80 ° C.

((D) alkylbenzene)
The alkylbenzene as the component (D) used in the present invention is not particularly limited, but the alkyl group of the alkylbenzene usually has 1 to 4 carbon atoms, for example, methyl group, ethyl group, isopropyl group, butyl group, etc. Can give.
Specific examples include ethylbenzenes such as monoethylbenzene, diethylbenzene, triethylbenzene or tetraethylbenzene, isopropylbenzenes such as monoisopropylbenzene, diisopropylbenzene or triisopropylbenzene, monoisopropyl toluene, diisopropyl toluene or triisopropyl toluene. Examples include isopropyl toluenes.
Among these, 1,3,5-triisopropylbenzene, triethylbenzene and triisopropyltoluene are preferable.

  In the immersion oil for microscope of the present invention, the liquid olefin polymer as the component (A), the liquid diene copolymer as the component (B), the diarylalkane as the component (C), and the component (D). The blending ratio of the alkylbenzene can be appropriately set, but (B) component 1 to 30 parts by mass, (C) component 40 to 80 parts by mass, and (D) component 2 to (A) component 100 parts by mass. 30 parts by mass is preferred. More preferable blending mass ratios are (B) component 2 to 20 parts by mass, (C) 50 to 70 component parts by mass, and (D) component 5 to 25 parts by mass with respect to 100 parts by mass of component (A).

When the blending ratio of the component (A), the component (B), the component (C) and the component (D) is within the above range, the resulting immersion oil tends to have lower fluorescence, and the refractive index, Abbe Number, kinematic viscosity, resolving power and other properties tend to be good.
Here, other characteristics required for immersion oil include non-drying, appearance, weather resistance, non-corrosion, contrast, chromatic aberration, and transparency.
By using the above blending ratio, the immersion oil is low in fluorescence, can maintain its characteristics over a long period of time, and is excellent in other various characteristics.

Moreover, there is no restriction | limiting in particular in the mixing | blending order of (A) component, (B) component, (C) component, and (D) component, It can mix | blend in various orders simultaneously or in steps.
Moreover, there is no restriction | limiting in particular also about the method of mixing | blending, Usually, the method of mix | blending by stirring and mixing near normal temperature is used suitably.
As long as the effect of the original immersion oil is not impaired, the usual additives and compounding agents used for the microscope immersion oil such as the fluorescence microscope immersion oil should be used for the immersion oil for the microscope of the present invention. Can do.
The immersion oil for a microscope of the present invention thus obtained can be suitably used as an immersion oil for a microscope, particularly an immersion oil for a fluorescence microscope.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these Examples.
In addition, evaluation of the various characteristics of the immersion oil for microscopes was performed using the following method.

<Evaluation method of immersion oil for microscope>
Fluorescence intensity The fluorescence microscope used a xenon lamp that emits ultraviolet light that excites fluorescence as a light source. The excitation light used is U excitation (366 nm), B excitation (488 nm), and G excitation (550 nm). An immersion oil that produces a small amount of fluorescence at each excitation is desirable for a fluorescence microscope. The fluorescence intensity of the immersion oil prepared in each example was measured with a spectrofluorophotometer “F-2500” manufactured by Hitachi, Ltd.
(2) Low fluorescence Evaluation was made based on the darkness of the background when observed with a fluorescence microscope using the immersion oil.
Good (◯): Bad black appearance (×): Looks a little bright (3) Change in fluorescence intensity over time (U excitation)
A sample of 30 g was placed in a glass bottle, and the value of the fluorescence intensity ratio (U excitation) before and after heating at 50 ° C. for 8 weeks was measured and evaluated in the following two stages.
Good (O): The value of the fluorescence intensity ratio is 2.0 or less. Poor (x): The value of the fluorescence intensity ratio exceeds 2.0. (4) Refractive index (n23D) and Abbe number (ν23D)
All were based on JIS K2101. A preferable refractive index range for the microscope immersion oil is 1.5140 to 1.5160, and a preferable Abbe number range for the microscope immersion oil is 38 to 44. The refractive index and the Abbe number were evaluated in two stages. If the refractive index is good, the resolving power is good, and if the Abbe number is good, the chromatic aberration is also good.
Good refractive index (◯): Refractive index value is 1.5140 to 1.5160
Refractive index defect (x): Refractive index value out of the above range Abbe number good (O): Abbe number value is 38 to 44
Abbe number defect (x): Abbe number value is outside the above range (5) Kinematic viscosity
The kinematic viscosity at 25 ° C. was measured according to JIS K2283. A preferable kinematic viscosity range for the immersion oil for microscope is 100 to 1,000 mm ² / sec (25 ° C.). The good and bad kinematic viscosity was evaluated in the following two stages.
Good (◯): 100 to 1,000 mm ² / sec Poor (×): Outside the above range (6) Non-drying property According to JIS C2201 “Electrical insulating oil” evaporation test, the test was performed at 30 ° C. × 24 hours, Evaluation was made in the following two stages.
Good (O): Less than 1% by mass of evaporation Poor (x): Evaporation of 1% by mass or more (7) Appearance Samples were taken in a clean glass container, checked for turbidity, and evaluated in the following two stages.
No turbidity: (○)
There is turbidity: (×)
(8) Weather resistance
The following two steps are performed according to the results of the light irradiation test and the heat accelerated deterioration test, which are the evaluation methods described in the following (8-1) and (8-2), and the refractive index, Abbe number, and hue before and after the test. It was evaluated with.
Good (O): No change in refractive index, Abbe number, and hue.
Defect (x): There is a change in any of refractive index, Abbe number, and hue.
(8-1) Light Irradiation Test A fixed amount (40 ± 0.5 g) of a sample was taken in a petri dish, and the change in refractive index after irradiation with light for a certain time (24, 72, 120 hours) was measured.
(8-2) Heating accelerated deterioration test (storage stability test)
A fixed amount (40 ± 0.5 g) of sample is put into a 50 mL conical flask with a stopper and kept in a constant temperature (40, 70 ° C.) constant temperature bath for 24 hours, after which the refractive index, Abbe number, and hue change Was observed.
(9) Non-corrosive
The presence or absence of corrosivity was examined by measuring the total acid value (JIS K2501) and the effect on the smear sample dye (JIS K2400), and evaluated in the following two stages.
(○): No corrosion (×): Corrosion (10) Contrast In the microscope using the immersion oil, see the black and white lines engraved on a black and white plate with chromium vapor deposition. It was evaluated by.
Good (○): clear Poor (×): unclear
(11) Transparency It was evaluated in the following two stages according to the transmittance (JISK 0115).
Good (O): 95% or more Poor (x): Less than 95%

<Reference Example 1>
12 parts by mass of polyisoprene (manufactured by Kuraray Co., Ltd., “LIR-30”; number average molecular weight 30000) with respect to 100 parts by mass of polybutene (manufactured by Idemitsu Kosan Co., Ltd., product name “Polybutene 100R”; number average molecular weight 1000), 32 parts by mass of 1-phenyl-1- (3,4-dimethylphenyl) ethane (lot number PXE-1), 32 parts by mass of 1-phenyl-1- (4-ethylphenyl) ethane (lot number PEBE-1), 18 parts by mass of 1,3,5-triisopropylbenzene was mixed at 25 ° C. for 10 minutes to prepare an immersion oil for microscope. Each evaluation result is shown in Table 1.
<Reference Examples 2, 3 and Comparative Example 1>
A microscope immersion oil was prepared in the same manner as in Reference Example 1 except that the lot of 1-phenyl-1- (3,4-dimethylphenyl) ethane was changed as shown in Table 1. The evaluation results are shown in Table 1.

<Evaluation results of Reference Examples 1 to 3 and Comparative Example 1>
As shown in Table 1, the microscopic immersion oil of Comparative Example 1 using 1-phenyl-1- (3,4-dimethylphenyl) ethane of lot number PXE-4 was obtained from other lot numbers (PXE-1 to PXE). It was found to be inferior in low fluorescence as compared with the immersion oil for microscopes of Reference Examples 1 to 3 using 1-phenyl-1- (3,4-dimethylphenyl) ethane of 3).

Next, 1-phenyl-1- (3,4-dimethylphenyl) ethane of lot number PXE-4 was subjected to the following pretreatment.
<Pretreatment of diarylalkane>
(1) Pretreatment with adsorbent (silica, activated clay, ion exchange resin) At room temperature (25 ° C.), about 300 g of 1-phenyl-1- (3,4-dimethylphenyl) ethane of lot number PXE-4 and hexane 300 mL was added and placed in a 1 L flask, and 50 g of adsorbent was added and mixed. The mixture was stirred at room temperature for 1 hour and then the solid content was removed by filtration. Further, the solvent was distilled off with an evaporator.
(2) Pretreatment by distillation Approximately 300 g of 1-phenyl-1- (3,4-dimethylphenyl) ethane of lot number PXE-4 was placed in a 500 mL flask, and a packed tower type precision distillation apparatus was set and the pressure was reduced to 1 mmHg. . The kettle temperature was heated to about 125 ° C, and distillation was performed at a reflux ratio of 1/3 and a distillation temperature of 108-110 ° C. After distilling off about 10 g of the first fraction, about 200 g was collected.
(3) Pretreatment by heat treatment About 300 g of 1-phenyl-1- (3,4-dimethylphenyl) ethane of lot number PXE-4 was placed in a 300 mL flask, heated at 70 ° C. in air for 48 hours, and then released. Chilled.

<Examples 1-5>
An immersion oil for microscope was prepared in the same manner as in Comparative Example 1 except that 1-phenyl-1- (3,4-dimethylphenyl) ethane (lot number PXE-4) was pretreated as shown in Table 1. Each evaluation result is shown in Table 1.

<Evaluation results of Examples 1 to 5>
In Examples 1-5, 1-phenyl-1- (3,4-dimethylphenyl) ethane (lot number PXE-4) was subjected to each pretreatment to obtain immersion oil for a microscope. It was possible to realize low fluorescence that could not be realized without it.

<Reference Example 4>
Polyisoprene (manufactured by Idemitsu Kosan Co., Ltd., product name “Polybutene 100R”; number average molecular weight 1000) 100 parts by mass, polyisoprene (Kuraray Co., Ltd. LIR-30; number average molecular weight 30000) 12 parts by mass, 1-phenyl 32 parts by mass of -1- (3,4-dimethylphenyl) ethane (lot number PXE-1), 32 parts by mass of 1-phenyl-1- (4-ethylphenyl) ethane (lot number PEBE-2), 1,3 Then, 18 parts by mass of 5-triisopropylbenzene was mixed at 25 ° C. for 10 minutes to prepare an immersion oil for microscope. Each evaluation result is shown in Table 2.

<Reference Example 5, Comparative Example 2>
A microscope immersion oil was prepared in the same manner as in Reference Example 4 except that the lot of 1-phenyl-1- (4-ethylphenyl) ethane was changed as shown in Table 2. Each evaluation result is shown in Table 2.

<Evaluation results of Reference Examples 4 and 5 and Comparative Example 2>
As shown in Tables 1 and 2, the microscopic immersion oil of Comparative Example 2 using 1-phenyl-1- (4-ethylphenyl) ethane of lot number PEBE-4 was measured with other lot numbers (PEBE-1 to PEBE-1). Compared with the immersion oil for microscopes of Reference Examples 1, 4 and 5 using 1-phenyl-1- (4-ethylphenyl) ethane of PEBE-3), it was found to be inferior in low fluorescence.
Next, pretreatment was performed on 1-phenyl-1- (4-ethylphenyl) ethane of lot number PEBE-4. The pretreatment method is the same as the method described in <Pretreatment of diarylalkane> above.

<Examples 6 to 10>
An immersion oil for a microscope was prepared in the same manner as in Comparative Example 2 except that 1-phenyl-1- (4-ethylphenyl) ethane (lot number PEBE-4) was pretreated as shown in Table 2. Each evaluation result is shown in Table 2.

<Evaluation results of Examples 6 to 10>
In Examples 6 to 10 in which each pretreatment was performed on 1-phenyl-1- (4-ethylphenyl) ethane (lot number PEBE-4) to obtain immersion oil for a microscope, no pretreatment was performed. Low fluorescence that could not be realized in some cases was realized.

  From the above, when diarylalkane was used without any pretreatment selected from adsorption treatment, distillation treatment or heat treatment, depending on the lot, it resulted in inferior low fluorescence as immersion oil for microscopes. . This is not preferable from the viewpoint of stable production of immersion oil for microscopes. On the other hand, it was found that good low fluorescence can be realized by subjecting the diarylalkane to a pretreatment selected from an adsorption treatment, a distillation treatment, and a heat treatment.

  The immersion oil for microscopes of the present invention is particularly suitably used for fluorescent microscopes.

Claims (12)

  (A) a liquid olefin polymer, (B) a liquid diene polymer, (C) a diarylalkane subjected to at least one pretreatment selected from the group consisting of adsorption treatment, distillation treatment and heat treatment, and (D ) Immersion oil for microscope characterized by containing alkylbenzene.   The immersion oil for microscopes according to claim 1, wherein the (C) diarylalkane is the pretreated phenylxylylethane and / or the pretreated phenylethylphenylethane.   The immersion oil for microscopes according to claim 1 or 2, wherein the pretreatment is a distillation treatment.   The immersion oil for microscopes according to claim 1 or 2, wherein the pretreatment is an adsorption treatment selected from a clay treatment or an ion exchange resin treatment.   (A) 1-30 parts by mass of (B) liquid diene polymer, 40-80 parts by mass of (C) diarylalkane, and (D) 2-30 of alkylbenzene with respect to 100 parts by mass of liquid olefin polymer. The immersion oil for microscopes as described in any one of Claims 1-4 containing a mass part. The immersion oil for microscopes as described in any one of Claims 1-5 whose number average molecular weights of the said (A) liquid olefin type polymer are 300-25,000. The immersion oil for microscopes according to any one of claims 1 to 6, wherein the (A) liquid olefin polymer is polybutene. The immersion oil for microscopes as described in any one of Claims 1-7 whose said (A) liquid olefin polymer is a liquid olefin polymer which performed the hydrogenation process. The immersion oil for microscopes as described in any one of Claims 1-8 whose number average molecular weights of the said (B) liquid diene polymer are 1,000-100,000. The immersion oil for microscopes according to any one of claims 1 to 9, wherein the (B) liquid diene polymer is polyisoprene. The immersion oil for microscopes as described in any one of Claims 1-10 whose said (D) alkylbenzene is 1,3,5- triisopropylbenzene. The immersion oil for a microscope according to any one of claims 1 to 11, which is an immersion oil for a fluorescence microscope.