JP2020063375A - Composite particle, method for producing the same, oil separation agent, and oil-water separation method - Google Patents

Abstract

To provide composite particles that are suitably usable as an oil adsorption agent, an industrially advantageous production method of the same, and an oil adsorption agent and an oil-water separation method using the composite particles.SOLUTION: Composite particles contain a condensate of a fluoroalkyl group-containing oligomer having an alkoxysilyl group, and magnetic iron oxide particles. The particles are produced by adding alkali to a reaction raw material solution containing a fluoroalkyl group-containing oligomer having an alkoxysilyl group and magnetic iron oxide particles, and subjecting the solution to a hydrolysis reaction. There is also provided an oil adsorbent agent containing the composite particles. There are also provided an oil-water separation method that brings the oil adsorption agent into contact with a treatment liquid containing water and oil, and adsorbs oil of the treatment liquid on the oil adsorption agent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to composite particles, a method for producing the same, an oil separating agent and an oil / water separating method using the composite particles.

  Fluorine compounds have characteristics such as water repellency / oil repellency, oxygen permeability, and low refractive index. Utilizing these characteristics, application to paints, cosmetics, wastewater treatment, etc. is being studied. However, since the fluorine compound has very high water repellency and oil repellency, it is difficult to maintain the dispersion stability in a non-fluorine raw material. Further, when a fluorine compound that exhibits high oil repellency in air is used in water, there is a drawback that the oil repellency disappears and the oil spreads wet.

  By the way, wastewater containing oil discharged from factories is required to be appropriately treated from the viewpoint of preventing environmental pollution. Conventionally, in the oil-water separation treatment, methods such as static separation and centrifugal separation that utilize the difference in specific gravity and adsorption separation have been used. However, the stationary separation requires a lot of time, the centrifugal separation requires a large-scale device, and the adsorption separation is not suitable for treating a large amount of oil-water mixed liquid.

  As a fluorine compound that can be used for oil / water separation treatment, the present inventor previously used a fluoroalkyl group-containing oligomer, and provided various new functional materials and oil / water separation materials to which excellent properties due to the fluoroalkyl group-containing oligomer were imparted. Has been proposed (see Patent Documents 1 to 5). The present inventor also proposed magnetic iron oxide nanocomposite powder particles obtained by complexing magnetic iron oxide particles with a fluoroalkyl group-containing oligomer (see Patent Document 6).

JP, 2016-191039, A JP, 2016-180097, A JP, 2016-172249, A JP, 2008-39895, A JP, 2018-87275, A JP, 2010-235441, A

  However, the functional materials and oil-water separators described in Patent Documents 1 to 5 have room for improvement in improving water repellency and lipophilicity. Further, in the composite particles obtained by the method of Patent Document 6, there are also iron oxide particles that are not included in the fluoroalkyl group-containing oligomer, and there is room for improvement in terms of improving the inclusion rate (for example, (See FIG. 10 of Patent Document 6).

  Therefore, an object of the present invention is to provide a composite particle that can be suitably used as an oil adsorbent, an industrially advantageous production method thereof, and an oil adsorbent and an oil-water separation method using the composite particle. is there.

  While advancing the development of a new functional material using a fluoroalkyl group-containing oligomer, the present inventor added an alkali to a reaction raw material solution containing a specific fluoroalkyl group-containing oligomer having an alkoxysilyl group and magnetic iron oxide particles. In addition, the composite particles obtained by carrying out the reaction step of performing the hydrolysis reaction have excellent water repellency and lipophilicity because (1) the magnetic iron oxide particles are easily included in the condensate of the fluoroalkyl group-containing oligomer. And (2) it becomes an oil adsorbent having excellent adsorption performance for oil, and (3) oil is selectively adsorbed from a treatment liquid containing water and oil, and the oil is separated by magnetic separation. They have found that the adsorbent can be easily recovered, and that (4) the oil adsorbent having adsorbed the oil can be reused by washing with an organic solvent, and thus the present invention has been completed.

That is, the first invention to be provided by the present invention is a composite particle containing a condensate of a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1) and magnetic iron oxide particles. .

(Wherein, R ¹ and R _{^2, - (CF 2) p-} Y group, or _{-CF (CF 3) - [OCF} 2 CF (CF 3)] indicates the q-OC ₃ F ₇ group, R ¹ And R ² may be the same group or different groups, Y in R ¹ and R ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and p and q each independently represent 0 to 10 R ³ , R ⁴ and R ⁵ may be the same group or different groups, and R ³ , R ⁴ and R ⁵ are linear or branched having 1 to ⁵ carbon atoms. Represents an alkyl group, and m is an integer of 2 to 3.)

The second invention to be provided by the present invention is to add an alkali to a reaction raw material solution containing a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1) and magnetic iron oxide particles. In addition, it is a manufacturing method of composite particles provided with a reaction process of performing a hydrolysis reaction.

(Wherein, R ¹ and R _{^2, - (CF 2) p-} Y group, or _{-CF (CF 3) - [OCF} 2 CF (CF 3)] indicates the q-OC ₃ F ₇ group, R ¹ And R ² may be the same group or different groups, Y in R ¹ and R ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and p and q each independently represent 0 to 10 R ³ , R ⁴ and R ⁵ may be the same group or different groups, and R ³ , R ⁴ and R ⁵ are linear or branched having 1 to ⁵ carbon atoms. Represents an alkyl group, and m is an integer of 2 to 3.)

  A third invention to be provided by the present invention is an oil adsorbent containing the composite particles of the first invention.

  A fourth aspect of the present invention is to provide an oil adsorbent of the third aspect of the present invention and a treatment liquid containing water and oil in contact with each other to convert the oil of the treatment liquid to the oil adsorbent. It is an oil-water separation method including an adsorption step of adsorbing.

  According to the present invention, composite particles excellent in water repellency and lipophilicity can be provided. Further, the composite particles can be suitably used as an oil adsorbent. Further, the oil adsorbent of the present invention can be washed and reused after adsorbing oil.

  Further, according to the present invention, the composite particles can be provided by an industrially advantageous method.

FIG. 1 is a transmission electron microscope (TEM) photograph of the composite particle sample obtained in Example 3. FIG. 2 is a transmission electron microscope (TEM) photograph of the composite particle sample obtained in Example 10. FIG. 3 is a photograph showing a state in which the samples of Comparative Example 1 and Example 3 were added to the treatment liquid containing dodecane, and then a magnet was placed on the side surface of the bottle. FIG. 4 is a photograph showing a state in which the samples of Comparative Example 1 and Example 12 were added to the treatment liquid containing dodecane, and then a magnet was placed above the petri dish. FIG. 5 is a photograph showing a state in which the samples of Comparative Example 3 and Example 20 were added to the treatment liquid (W / O type emulsion), and then a magnet was placed on the side surface of the bottle. FIG. 6 is a graph showing the Demulsification efficiency (light transmittance) of the supernatant after treating the treatment liquid (W / O type emulsion) with the samples of Examples 16 to 20 and Comparative Example 3. FIG. 7 is a photograph showing a state in which the samples of Comparative Example 3 and Example 19 were added to the treatment liquid (O / W type emulsion), and then a magnet was placed on the side surface of the bottle. FIG. 8: is a graph which shows the Demulsification efficiency (light transmittance) of the supernatant liquid after processing a processing liquid (O / W type emulsion) using the sample of Examples 16-20 and the comparative example 3. FIG. 9 is a graph showing changes in the amount of oil adsorbed when the cycle of the adsorption step, the recovery step and the washing step was repeated 5 times for the composite particle sample of Example 18.

  The present invention will be described below based on its preferred embodiments. The composite particles according to the present invention are magnetic and a condensate of a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1) (hereinafter, also simply referred to as “fluoroalkyl group-containing oligomer”). And iron oxide particles. In the following description, when described as “L to M” (where L and M are arbitrary numbers), it means “L or more and M or less” unless otherwise specified.

(Wherein, R ¹ and R _{^2, - (CF 2) p-} Y group, or _{-CF (CF 3) - [OCF} 2 CF (CF 3)] indicates the q-OC ₃ F ₇ group, R ¹ And R ² may be the same group or different groups, Y in R ¹ and R ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and p and q each independently represent 0 to 10 R ³ , R ⁴ and R ⁵ may be the same or different, and R ³ , R ⁴ and R ⁵ are linear or branched having 1 to ⁵ carbon atoms. Represents an alkyl group, and m is an integer of 2 to 3.)

  The fluoroalkyl group-containing oligomer represented by the general formula (1) is used to impart excellent water repellency to the composite particles of the present invention.

Formula (1) of R ¹ and _{^{R 2 - (CF 2) p}} -Y group, or _{-CF (CF 3) - [OCF} 2 CF (CF 3)] p and q-OC ₃ F ₇ group q is independently an integer of 0 to 10, and preferably an integer of 0 to 3. R ¹ and R ² may be the same group or different groups. In particular, from the viewpoint of further improving water repellency and lipophilicity, both R ¹ and R ² are preferably —CF (CF ₃ ) OC ₃ F ₇ groups.

As shown in the general formula (1), the fluoroalkyl group-containing oligomer has a hydrolyzable alkoxysilyl group. Examples of the linear or branched alkyl group having 1 to 5 carbon atoms represented by R ³ , R ⁴ and R ⁵ in the general formula (1) include a methyl group, an ethyl group, a propyl group, a butyl group, and Examples thereof include a pentyl group. R ³ , R ⁴ and R ⁵ may be the same group or different groups.

  The fluoroalkyl group-containing oligomer represented by the general formula (1) is produced, for example, by reacting trialkoxyvinylsilane such as trimethoxyvinylsilane with fluoroalkanoyl peroxide. The method for producing the oligomer can be obtained, for example, by the method described in JP-A-2002-338691 or JP-A-2010-77383.

The composite particles of the present invention include magnetic iron oxide particles. Examples of magnetic iron oxide particles include particles of magnetite (Fe ₃ O ₄ ), maghemite (γ-Fe ₂ O ₃ ), FeO.Fe ₂ O ₃ , MnO.Fe ₂ O ₃ , NiO.Fe ₂ Examples thereof include ferrite particles such as O ₃ and CoO.Fe ₂ O _3, which may be used alone or in combination. The composite particles of the present invention have more excellent water repellency and lipophilicity as compared with the prior art by using magnetic iron oxide particles in addition to the condensate of the fluoroalkyl group-containing oligomer to compound them. It is expressed. The composite particles having such characteristics are also suitably used as an oil adsorbent described later.

  From the viewpoint of successfully producing composite particles having excellent water repellency and lipophilicity, the magnetic iron oxide particles are preferably magnetite particles or maghemite particles. The magnetic iron oxide particles contain other iron compounds such as α-hemite and iron hydroxide, and other metal elements such as nickel, cobalt, manganese, and aluminum as long as the effects of the present invention are not impaired. Good.

  The average particle size of the magnetic iron oxide particles is preferably 5 nm to 1000 nm, more preferably 10 nm to 800 nm, from the viewpoint of successfully obtaining composite particles having excellent water repellency and hydrophilicity. Used. The average particle diameter can be determined as a volume cumulative particle diameter D50 at a cumulative volume of 50% by volume by a laser diffraction / scattering particle size distribution measuring method. For example, magnetic iron oxide particles dispersed in a solvent such as methanol or ethanol can be used in Examples. It can be measured by using the particle size distribution measuring device described in detail in.

  As shown in FIG. 1 and FIG. 2, the composite particles of the present invention show that one or two or more magnetic iron oxide particles are fluoroalkyl when observed by a transmission electron microscope (hereinafter, also referred to as “TEM”). It is preferably present in the form of inclusion in the condensate of the group oligomer. In particular, the composite particles of the present invention more preferably have a structure in which the condensate of the fluoroalkyl group-containing oligomer is dispersed and arranged on the surface of the magnetic iron oxide particles. The condensate of the fluoroalkyl group-containing oligomer is preferably uniformly dispersed and clathrated on the surface of the magnetic iron oxide particles as the core material. The term “uniformly dispersed” means that (i) the condensate of fluoroalkyl group-containing oligomers is sparsely and uniformly arranged so that the surface of the magnetic iron oxide particles as the core material is exposed, and (ii) ) Both dispersion states in the case where the condensate of the fluoroalkyl group-containing oligomer is densely and uniformly arranged so that the surface of the magnetic iron oxide particles as the core material are not exposed are included. From the viewpoint that the composite particles of the present invention easily exhibit lipophilicity and water repellency, the condensate of the fluoroalkyl group-containing oligomer is dispersed and arranged in the state of (i) on the surface of the magnetic iron oxide particles as the core material. Is preferably provided.

  From the viewpoint of further enhancing the water repellency and lipophilicity and enhancing the adsorption ability to oil, the content of the magnetic iron oxide particles in the composite particles is preferably 5 mg to 1000 mg with respect to 100 mg of the condensate of the fluoroalkyl group-containing oligomer. , And more preferably 10 mg to 700 mg. The content of magnetic iron oxide particles in the composite particles can be measured, for example, by thermogravimetric analysis using a thermogravimetric analyzer.

  The average particle size of the composite particles of the present invention is preferably 10 nm to 7000 nm, more preferably 50 nm to 5000 nm. When the average particle diameter is within this range, the water repellency and lipophilicity of the composite particles are effectively exhibited, and the dispersibility in various dispersion solvents, resin materials, various base materials and the like is improved. Further, when used as an oil adsorbent, the oil adsorbability becomes excellent. The average particle diameter is, for example, the volume cumulative particle diameter D50 at a cumulative volume of 50% by volume measured by a laser diffraction / scattering particle size distribution measurement method using a particle size distribution measuring device described below using composite particles dispersed in a solvent such as methanol or ethanol. You can ask.

  The composite particles of the present invention are preferably produced by a method including a reaction step of adding an alkali to a reaction raw material solution containing a fluoroalkyl group-containing oligomer and magnetic iron oxide particles and performing a hydrolysis reaction.

  The fluoroalkyl group-containing oligomer relating to the reaction step is an oligomer represented by the above general formula (1) and has a hydrolyzable alkoxysilyl group. As the magnetic iron oxide particles, those mentioned above can be used.

  The reaction raw material solution containing a fluoroalkyl group-containing oligomer and magnetic iron oxide particles can be a dispersion liquid containing, for example, a fluoroalkyl group-containing oligomer, magnetic iron oxide particles, and a reaction solvent. As the reaction solvent, those capable of dissolving the fluoroalkyl group-containing oligomer are preferably used. Examples of such a reaction solvent include lower alcohols such as methanol, ethanol, n-propanol, and isopropanol. Of these, methanol or ethanol is particularly preferable from the viewpoint of production efficiency.

  In the reaction step, the order of mixing the fluoroalkyl group-containing oligomer and the magnetic iron oxide particles when preparing the reaction raw material solution is not particularly limited. As the mixing order, for example, one of the fluoroalkyl group-containing oligomer and the magnetic iron oxide particles may be added to the reaction solvent, and then the other may be further added to form a reaction raw material solution, and both may be added to the reaction solvent at once. May be used as the reaction raw material solution, or the reaction solvent may be added after mixing the fluoroalkyl group-containing oligomer and the magnetic iron oxide particles to obtain the reaction raw material solution.

  The content of the magnetic iron oxide particles in the reaction raw material solution is preferably 5 mg to 1000 mg, more preferably 10 mg to 700 mg, based on 100 mg of the fluoroalkyl group-containing oligomer represented by the general formula (1). When the content of the magnetic iron oxide particles in the reaction raw material solution is in such a range, the resulting composite particles have successfully exhibited water repellency and lipophilicity.

  The content of the reaction solvent in the reaction raw material solution is preferably 500 parts by mass to 10000 parts by mass, and more preferably 1000 parts by mass with respect to 100 parts by mass as the total mass of the fluoroalkyl group-containing oligomer and the magnetic iron oxide particles. ~ 8000 parts by mass.

  From the viewpoint of obtaining composite particles effectively exhibiting water repellency and lipophilicity, the magnetic iron oxide particles having an average particle size of preferably 5 nm to 1000 nm, more preferably 10 nm to 800 nm are used for the reaction. It is preferred to perform the steps.

  In the reaction step, the alkali added to the reaction raw material solution is not particularly limited as long as it can hydrolyze the alkoxysilyl group in the fluoroalkyl group-containing oligomer and can condense the fluoroalkyl group-containing oligomer. Examples of such an alkali include hydroxides such as ammonium hydroxide, sodium hydroxide, and potassium hydroxide. Ammonium hydroxide is preferable from the viewpoint of increasing reactivity and increasing production efficiency.

  The mixing amount of the alkali added to the reaction raw material solution is not particularly limited and is appropriately selected. The reaction temperature at the time of carrying out hydrolysis by mixing an alkali with the reaction raw material solution is preferably -5 ° C to 50 ° C, more preferably 0 ° C to 30 ° C. When the reaction temperature is -5 ° C or higher, the hydrolysis rate of the alkoxysilyl group does not become excessively slow, and sufficient reaction efficiency can be obtained. The stability can be increased. The time for mixing the reaction raw material solution with an alkali for hydrolysis is appropriately selected without limitation, but is preferably 1 hour to 72 hours, and more preferably 1 hour to 50 hours. In the reaction step, the reaction raw material solution may be stirred to carry out the hydrolysis reaction, if necessary.

  Through the above steps, a post-reaction dispersion containing the composite particles according to the present invention is obtained. The composite particles contained in this dispersion have a condensate of a fluoroalkyl group-containing oligomer having a siloxane bond as the main skeleton formed on the surface of the magnetic iron oxide particles. After completion of the reaction, the solvent is removed under reduced pressure by a conventional method, or the solid content is recovered by solid-liquid separation by filtration or magnetic separation by a magnet or the like, and further purified by washing, drying or the like, if necessary. Then, the desired composite particles can be obtained.

  The composite particles according to the present invention may be used alone or in combination with other base materials such as glass, film, natural fiber or synthetic fiber, silica, alumina and sand, for example, magnetic tape, high density. It can be used as a magnetic recording medium, an electromagnetic wave shielding material, a magnetic material such as an in vitro diagnostic agent, or an oil adsorbent. In particular, the composite particles according to the present invention can be suitably used as an oil adsorbent.

  The oil adsorbent of the present invention contains the composite particles described above. For example, when dodecane is used as the oil, the oil adsorbent of the present invention has an adsorption amount of 1 g or more, preferably 1.1 g to 3 g, per 1 g of composite particles. In particular, the oil adsorbent of the present invention contains the composite particles in which the condensate of the fluoroalkyl group-containing oligomer and the magnetic iron oxide particles are complexed, so that the excellent lipophilicity of the particles is exhibited.

  The "oil" in the present specification is generally a compound having an oil-soluble group, the property that water and oil are not separated from each other and mixed, and the property that water and oil form a uniform or non-uniform dispersion liquid. , Or a combination of these. These properties can be confirmed or measured, for example, visually or using an optical microscope when water and oil are dispersed by emulsification or the like. Specific examples of oils satisfying such properties include acyclic or cyclic hydrocarbons such as dodecane and cyclohexane, oils and fats such as vegetable oils and animal fats, and mineral oils such as heavy oil, kerosene, gas oil and gasoline. To be

  The oil-water separation method using the oil adsorbent of the present invention comprises contacting the oil adsorbent with a treatment liquid containing water and oil to be treated in the oil-water separation, and converting the oil in the treatment liquid into the oil adsorbent. An adsorption step of adsorbing is provided. As an example of the adsorption step, a powdery oil adsorbent is added to a treatment liquid containing water and oil, and the oil contained in the treatment liquid is selectively adsorbed on the oil adsorbent to separate water and oil. To do. The oil adsorbent of the present invention may be added to treated water containing water and oil in a stationary state, and if necessary, the adsorption step may be carried out under stirring such as ultrasonic dispersion.

  The treatment liquid to be treated in the oil-water separation method is not particularly limited as long as it contains water and oil. In detail, for example, industrial wastewater containing oil drained from factories, restaurants, etc., domestic wastewater containing oil, seawater containing oil, river water, lake water, etc. may be mentioned. The mixed form of water and oil in the treatment liquid may be a form in which water and oil are separated into two or more layers, may be a clear solution form, and may be a W / O type emulsion or an O / W type emulsion. It may be in the form of emulsion such as emulsion. From the viewpoint of realizing simple and effective oil-water separation, it is preferable to perform oil-water separation by treating a treatment liquid in the form of a solution or an emulsion.

  The amount of the oil adsorbent added to the treatment liquid can be appropriately changed depending on the type and amount of oil contained in the treatment liquid, the mixing form of water and oil, and the like. For example, when treated water containing dodecane as oil is to be treated, 0.3 g to 3 g, preferably 0.6 g to 2.5 g of an oil adsorbent can be added to 1 g of dodecane. From the viewpoint of successfully performing oil-water separation, the amount of the oil adsorbent added to the treatment liquid is preferably determined in advance by an experiment using the treatment liquid to be treated.

  While successfully recovering the oil adsorbent used for oil-water separation from the treatment liquid, from the viewpoint of enabling the oil contained in the treatment liquid to be selectively and effectively recovered, the oil-water separation method of the present invention performs the adsorption step. After that, it is preferable to further include a recovery step of magnetically separating the oil adsorbent on which the oil is adsorbed and recovering the oil adsorbent from the treatment liquid.

  As described above, since the oil adsorbent of the present invention contains the composite particles, it has a high affinity for the oil contained in the treatment liquid and a high water repellency for the water contained in the treatment liquid. Further, since the composite particles contain magnetic iron oxide particles in the core material, they can be easily attracted by the magnetic force applied from the outside. When, for example, a magnet is used as the material for generating the magnetic force, the oil adsorbent after the adsorption step is attracted to the magnet side by the magnetic force of the magnet while adsorbing the oil in the treatment liquid. In this way, it is possible to easily and effectively separate water and oil from the treatment liquid while recovering the added oil adsorbent.

  The magnet that can be used for magnetic separation in the recovery step is not particularly limited, but for example, a permanent magnet, a superconducting bulk magnet, an electromagnet, or the like can be used.

  It is preferable that the oil-water separation method of the present invention further comprises a washing step of washing the collected oil adsorbent with an organic solvent after the adsorption step so that the oil adsorbent can be reused as an oil adsorbent. As the organic solvent for washing and removing the adsorbed oil from the oil-organic material, any organic solvent that can dissolve the oil and is inert to the oil adsorbent can be used without particular limitation. Examples of such organic solvents include lower alcohols such as methanol, ethanol, n-propanol and isopropanol, ketones such as acetone, acyclic or cyclic ethers such as diethyl ether and tetrahydrofuran, acyclic or cyclic ethers such as n-hexane and cyclohexane. Cyclic alkanes as well as mixtures thereof can be used. By going through such a step, oil-water separation can be effectively performed a plurality of times without using a new oil adsorbent, so that the cost of oil-water separation can be further reduced.

  The method for cleaning the oil adsorbent in the cleaning step is not particularly limited, and for example, methods such as stirring in an organic solvent, ultrasonic dispersion, and immersion in an organic solvent can be performed. After the washing step, purification such as drying may be further performed to obtain a reusable oil adsorbent.

  Further, the oil adsorbent of the present invention may be used in the form of powder, and if necessary, the oil adsorbent may be molded by a conventional method, and the molded product obtained thereby may be used as the oil adsorbent.

  Examples of the molding process include a granulation process for molding a powdery oil adsorbent into granules, or a method of coating the surface of a resin core material with the oil adsorbent of the present invention, natural fiber or synthetic fiber. An example is a method in which an oil adsorbent is adhered to the surface and / or the inside of a nonwoven fabric formed of fibers to fix the nonwoven fabric into a sheet. Examples of the granulation method include known methods, for example, stirring and mixing granulation, tumbling granulation, extrusion granulation, crush granulation, fluidized bed granulation, spray drying granulation (spray dry), compression granulation. Examples thereof include grains. If necessary, a binder or solvent may be added and mixed in the granulation process. As the binder, known binders such as polyvinyl alcohol, polyethylene oxide, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, starch, corn starch, molasses, lactose, gelatin. , Dextrin, gum arabic, alginic acid, polyacrylic acid, glycerin, polyethylene glycol, polyvinylpyrrolidone and the like. Various solvents such as an aqueous solvent and an organic solvent can be used as the solvent.

  Hereinafter, the present invention will be described with reference to examples, but the scope of the present invention is not limited to these examples.

<Fluoroalkyl group-containing oligomer>
As the fluoroalkyl group-containing oligomer (hereinafter referred to as “VM”), an oligomer having the skeleton of the general formula (1) and the substituents shown in Table 1 below was used. The molecular weights shown in Table 1 are number average molecular weights by gel permeation chromatography (GPC, polystyrene conversion).

[Examples 1 to 9]
The amount of VM shown in Table 2 below was dissolved in 20 mL of methanol to prepare a VM solution, and the amount of magnetite particles (Fe ₃ O ₄ : manufactured by Toda Kogyo Co., Ltd.) shown in Table 2 was added to this solution to prepare a reaction raw material solution. Were prepared respectively. The average particle diameter D50 of the magnetite particles is as shown in Table 2. 0.3 mL of 25 mass% ammonia water was added to these reaction raw material solutions, and the mixture was stirred for 5 hours at room temperature (25 ° C.) using a magnetic stirrer to obtain a post-reaction dispersion containing composite particles. After the reaction, a permanent magnet was brought close to the dispersion liquid to magnetically separate and collect the target substance, and the collected target substance was dried to obtain a composite particle sample. The yield (%) of the composite particle sample was calculated by dividing the mass of the added magnetite particles by the ratio of the mass of the obtained composite particle sample. The yield indicates the production efficiency of composite particles, and the higher the yield, the more industrially advantageous.
As a result of TEM observation, it was confirmed that in the composite particle samples of the respective examples, the magnetite particles were included in the condensate of the fluorofluoroalkyl group-containing oligomer to form a composite. A TEM photograph of the composite particle sample obtained in Example 3 is shown in FIG.

[Comparative Examples 1 to 3]
Only magnetite particles having an average particle diameter D50 of 10 nm (Comparative Example 1), 40 nm (Comparative Example 2) and 200 nm (Comparative Example 3) were used. That is, each comparative example is a sample of magnetic iron oxide particles having no condensate of fluoroalkyl group-containing oligomer.

<Physical property evaluation>
The average particle size D50, the contact angle with dodecane, and the contact angle with water were measured for the composite particle sample obtained in the example and the particle sample of the comparative example. In addition, the same sample was evaluated for dispersibility in a solvent.

(1. Evaluation of average particle diameter D50)
The composite particle sample obtained in the example was dispersed in methanol and measured using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, SALD-300V).

(2. Evaluation of contact angle with dodecane and water)
The glass plate was immersed in the post-reaction dispersion containing the composite particles obtained in the example for 1 minute at room temperature (25 ° C.). After pulling up the glass plate, it was naturally dried, and then vacuum dried at 20 ° C. overnight. The contact angle (°) with dodecane and the contact angle (°) with water on the surface of the modified glass plate thus obtained were measured by Kyowa Interface Science Drop Master. 300 was used for each measurement. The smaller the contact angle, the higher the affinity with dodecane or water. The results are shown in Table 3 below. "-" In the table indicates that the contact angle did not change.

(3. Evaluation of dispersibility in a solvent)
Using the composite particle samples obtained in Examples 1, 3, 4, 6, 7, and 9 and the comparative particle sample, the dispersibility in the following solvents was evaluated according to the following criteria. For the evaluation, 0.01 g of the sample of the Example or Comparative Example was added to 5 mL of the solvent, and the dispersion state was visually observed. The solvent used was water (H ₂ O), methanol (MeOH), ethanol (EtOH), tetrahydrofuran (THF), 1,2-dichloroethane (DE), Cl ₂ CHCF ₂ CF ₃ and CClF ₂ CF ₂ CHClF. A mixed solvent having a mass ratio of 1: 1 (AK-225, manufactured by AGC Co.), dimethyl sulfoxide (DMSO), and dimethylformamide (DMF) were used. The results are shown in Table 4 below.

(Dispersion evaluation criteria)
X: The particle sample floats or precipitates in the solvent and is not dispersed at all.
B: Part of the particle sample is suspended or precipitated in the solvent, but some are dispersed.
◯: The particle sample is substantially uniformly dispersed without floating or settling in the solvent.

  As shown in Table 2, it is understood that the composite particles shown in each of the examples have a high yield and can be produced by an industrially advantageous method. In particular, by increasing the average particle diameter of the magnetic iron oxide particles or increasing the addition amount of the magnetic iron oxide particles, the yield of the composite particles is increased, and it can be produced by a more industrially advantageous method. I understand.

  Further, as shown in Table 3, the composite particles shown in each of the examples have a small contact angle with dodecane and a very large contact angle with water, and thus it is understood that they have lipophilicity and water repellency. On the other hand, it can be seen that the particles shown in each of the comparative examples have a small contact angle of dodecane and a small contact angle of water, and are not water repellent.

  Further, as shown in Table 4, it can be seen that the composite particles shown in each example are not dispersed in water at all and can be dispersed in each solvent having lipophilicity.

[Examples 10 to 20]
The amount of VM shown in Table 5 below was dissolved in 5 mL of methanol to form a VM solution, and the magnetic iron oxide particles (magnetite particles) having the average particle size and the amount shown in Table 5 were used, and the results of Examples 1 to 3 were used. Composite particle samples were prepared as in 9. As a result of TEM observation, it was confirmed that in the composite particle samples of each example, the magnetite particles were included in the condensate of the fluoroalkyl group-containing oligomer to form a composite. A TEM photograph of the composite particle sample obtained in Example 10 is shown in FIG.

<Physical property evaluation>
With respect to the composite particle samples obtained in Examples 10 to 18, the average particle diameter D50, the contact angle with dodecane, and the contact angle with water were measured by the methods described above. The average particle size of the composite particle samples of Examples 19 and 20 was measured. The results are shown in Table 6 below.

  As shown in Table 5, it can be seen that the composite particles shown in Examples 10 to 20 have high yields and can be produced by an industrially advantageous method, as in Examples 1 to 9. In particular, by increasing the average particle diameter of the magnetic iron oxide particles or increasing the addition amount of the magnetic iron oxide particles, the yield of the composite particles is increased, and it can be produced by a more industrially advantageous method. I understand.

  Further, as shown in Table 6, the composite particles shown in Examples 10 to 20 have a small contact angle with dodecane and a very large contact angle with water, and thus have lipophilicity and water repellency. I understand.

<Evaluation of oil-water separation performance>
The oil-water separation performance when the composite particles obtained by the above method was used as an oil adsorbent was evaluated by the methods described in Evaluations 1 to 4 below.

(Evaluation 1)
As shown in FIG. 3, 20 μL of dodecane, which was previously colored blue by pigment green MC, was added as an oil to a glass sample bottle containing 2 mL of water so as to float on the water surface. The separated processing liquid 1 was used. 20 mg of the composite particle sample obtained in Example 3 or the particle sample of Comparative Example 1 was added to the treatment liquid 1 in a stationary state, and an adsorption step was performed. Next, a permanent magnet was brought close to the side surface of the sample bottle, each sample was magnetically separated from the treatment liquid, and a recovery step was performed. The state of the sample bottle after the collecting step was visually observed, and the oil-water separation performance (oil adsorption performance) was evaluated according to the following criteria. The results are shown in FIG. 3 and Table 7.

(Evaluation 2)
As shown in FIG. 4, 20 μL of blue-colored dodecane was added to a petri dish containing 30 mL of water so as to be suspended, to obtain a treatment liquid 2 in which water and oil were separated into two layers. 50 mg of the composite particle sample obtained in Example 12 or the particle sample of Comparative Example 1 was added to the treatment liquid 2 in a stationary state, and an adsorption step was performed. Then, a permanent magnet was brought close to above the petri dish to magnetically separate each sample from the treatment liquid, and a recovery step was performed. The state of the petri dish after the collecting step was visually observed, and the oil-water separation performance (oil adsorption performance) was evaluated according to the following criteria. The results are shown in FIG. 4 and Table 8.

(Evaluation of oil adsorption performance)
X: Colored dodecane is observed on the water surface, and the oil adsorption performance is poor.
◯: Colored dodecane was not observed on the water surface, and the oil adsorption performance was good.

  As shown in FIGS. 3 and 4, and Tables 7 and 8, the composite particles of Examples 3 and 12 have higher oil adsorption performance than the particles of Comparative Example 1, and the treatment liquid containing water and oil. It can be seen from the above that the oil can be separated easily and effectively.

(Evaluation 3)
5 mL of dodecane, 0.468 mL of water, and 468 mg of Span 80 as an emulsifier were placed in a sample bottle and subjected to ultrasonication for 1 hour. Next, this was diluted 50 times with water to prepare the W / O type emulsion shown in FIG. Then, 50 mg of the composite particle sample of Examples 16 to 20 or the particle sample of Comparative Example 3 was added to a sample bottle containing 3 mL of the treatment liquid 3, and the adsorption step was performed. The sample bottle was capped, placed in an ultrasonic device (ASU CLEANER ASU-6, manufactured by As One Co., Ltd.), and the contents were stirred at room temperature for 30 minutes and then left standing for 3 minutes. Then, a permanent magnet was brought close to the side surface of the sample bottle to magnetically separate each sample from the treatment liquid, and a recovery step was performed. The outline of the recovery process is shown in FIG.

  The supernatant liquid was collected from the sample bottle after the collecting step, and the light transmittance of the liquid at 500 nm was measured using a UV spectrum device (manufactured by Shimadzu Corporation, UV-1800) with dodecane as a blank. The measurement result of the light transmittance is shown in FIG. 6 as “Demulsification efficiency”. The higher the value of the light transmittance, the more the emulsion breaks, indicating that the oil and water can be easily separated.

(Evaluation 4)
0.833 mL of dodecane, 5 mL of water, and 625 mg of Tween 80 as an emulsifier were put in a sample bottle and sonicated for 1 hour. Next, this was diluted 50 times with water to prepare an O / W type emulsion shown in FIG. Then, 50 mg of the composite particle sample of Examples 16 to 20 or the particle sample of Comparative Example 3 was added to a sample bottle containing 3 mL of the treatment liquid 4, and the adsorption step and the recovery step were performed in the same manner as in Evaluation 3. went. The outline of the recovery process is shown in FIG. The supernatant was collected from the sample bottle after the collecting step, and the light transmittance was measured in the same manner as in Evaluation 3. The results are shown in Fig. 8.

  As shown in FIGS. 6 and 8, the treatment liquids treated with the composite particles of Examples 16 to 20 have higher light transmittance than the particles of Comparative Example 3. That is, due to the high lipophilicity, the composite particles of the examples successfully exhibit oil-water separation performance even when a treatment liquid such as an emulsion in which water and oil are finely dispersed is treated. It is understood that it can be expressed.

<Evaluation of oil-water separation performance after washing process>
The change in oil-water separation performance when the oil adsorbent having adsorbed oil was washed was evaluated by the following method.

(Evaluation 5)
Using the composite particle sample of Example 18 as an oil adsorbent, the adsorption step and the recovery step were performed in the same manner as in Evaluation 2, the dodecane-adsorbed composite particles were recovered, and the mass A1 (mg) of the particles was measured. did. Next, the collected composite particles were dried at 25 ° C. for 1 hour, and the dried particles were washed with 5 mL of hexane to perform a washing step. After further drying at 80 ° C. for 12 hours, reusable composite particles were obtained (the series of steps is referred to as “1 cycle”). Further, the above cycle was repeated four times using reusable composite particles, and the mass A2 to A5 (mg) of the particles in each cycle was measured.

  As a control sample, the composite particle sample of Example 18 was added to a liquid containing no dodecane, the above adsorption step and the recovery step were performed to recover the composite particles, and the mass B1 (mg) of the particles was measured. Then, the above-mentioned washing process was performed to obtain reusable composite particles. The cycle was repeated 4 times using reusable composite particles, and the mass B2 to B5 (mg) of particles in each cycle was measured.

The oil-water separation performance was evaluated as the mass of adsorbed dodecane (Weight gain). Specifically, the difference in the mass of particles in each cycle was calculated as in the following formula (a). The results are shown in Fig. 9.
Mass of adsorbed dodecane (mg) = Ax (mg) -Bx (mg) (a)
(X indicates the number of cycles and is an integer of 1 to 5.)

As shown in FIG. 9, the composite particles of the present invention have sufficient lipophilicity and water repellency even after being subjected to multiple washing steps, exhibit high oil-water separation performance, and are reusable. It turns out to be a thing.

Claims (11)

Composite particles containing a condensate of a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1) and magnetic iron oxide particles.

(Wherein, R ¹ and R _{^2, - (CF 2) p-} Y group, or _{-CF (CF 3) - [OCF} 2 CF (CF 3)] indicates the q-OC ₃ F ₇ group, R ¹ And R ² may be the same group or different groups, Y in R ¹ and R ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and p and q each independently represent 0 to 10 R ³ , R ⁴ and R ⁵ may be the same or different, and R ³ , R ⁴ and R ⁵ are linear or branched having 1 to ⁵ carbon atoms. Represents an alkyl group, and m is an integer of 2 to 3.) The composite particle according to claim ^1, wherein R ¹ and R ^{2 in} the formula of the general formula (1) are —CF (CF ₃ ) OC ₃ F ₇ .   The composite particles according to claim 1 or 2, wherein the magnetic iron oxide particles are magnetite particles or maghemite particles.   The composite particle according to any one of claims 1 to 3, having an average particle diameter of 10 nm to 7000 nm. Composite particles including a reaction step of adding an alkali to a reaction raw material solution containing a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1) and magnetic iron oxide particles to carry out a hydrolysis reaction Manufacturing method.

(Wherein, R ¹ and R _{^2, - (CF 2) p-} Y group, or _{-CF (CF 3) - [OCF} 2 CF (CF 3)] indicates the q-OC ₃ F ₇ group, R ¹ And R ² may be the same group or different groups, Y in R ¹ and R ² represents a hydrogen atom, a fluorine atom or a chlorine atom, and p and q each independently represent 0 to 10 R ³ , R ⁴ and R ⁵ may be the same or different, and R ³ , R ⁴ and R ⁵ are linear or branched having 1 to ⁵ carbon atoms. Represents an alkyl group, and m is an integer of 2 to 3.)   The method for producing composite particles according to claim 5, wherein the reaction step is performed using the magnetic iron oxide particles having an average particle diameter of 5 nm to 1000 nm.   An oil adsorbent containing the composite particles according to any one of claims 1 to 4.   An oil-water separation method comprising an adsorption step of bringing the oil adsorbent according to claim 7 into contact with a treatment liquid containing water and oil to adsorb the oil of the treatment liquid to the oil adsorbent.   The oil-water separation method according to claim 8, further comprising a recovery step of magnetically separating the oil adsorbent on which the oil is adsorbed and recovering the oil adsorbent from the treatment liquid.   The oil-water separation method according to claim 9, further comprising a cleaning step of cleaning the recovered oil adsorbent with an organic solvent so that the oil adsorbent can be reused as an oil adsorbent.   The oil-water separation method according to any one of claims 8 to 10, wherein the form of the treatment liquid is a solution or an emulsion.