JP2016180097A - Composite particle, method for producing the same and oil-water separating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite particle that can be used suitably as oil-water separating material.SOLUTION: A composite particle comprises a condensate of a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by formula (1), talc and crosslinked polystyrene (Rand Rindependently represent -(CF) p-Y or -CF(CF)-[OCFCF(CF)]q-OCF; Y is H, F or Cl; p and q are an integer of 0-10; R-Rare a C1-5 linear or branched alkyl group; m is an integer of 2-3).SELECTED DRAWING: Figure 6

Description

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

  Fluorine compounds can be expected to be applied to paints, cosmetics, etc. by taking advantage of features such as water / oil repellency, oxygen permeability and low refractive index. However, since the fluorine-based compound has too high water and oil repellency, it is difficult to maintain dispersion stability with respect to the non-fluorine raw material.

  In addition, fluorine compounds that exhibit high oil repellency in air have the disadvantage that the oil repellency disappears in water and the oil spreads wet.

  Wastewater containing oil is a major cause of environmental pollution and is required to be treated appropriately. Conventionally, methods such as stationary separation such as specific gravity separation, centrifugal separation, and adsorption separation are used for oil-water separation treatment.

  However, stationary separation requires a lot of time, centrifugation requires a large-scale apparatus, and adsorption separation is unsuitable for processing a large amount of oil-water mixture.

  The present inventors have previously proposed various new functional materials using a fluoroalkyl group-containing oligomer and imparting excellent characteristics resulting from the fluoroalkyl group-containing oligomer (for example, Patent Documents 1 to 3) reference).

  In addition, the present inventors have previously obtained a fluoroalkyl group-containing oligomer having an alkoxysilyl group, talc, and further under alkaline conditions in the presence of various organic compounds such as 2-hydroxy-4-methoxybenzophenone, bisphenol AF, bisphenol A and the like. Proposed nano-composite particles in which talc and an organic compound are encapsulated by a sol-gel reaction in the method (see Non-Patent Document 1).

JP 2010-209300 A JP 2010-235943 A JP2013-185071A

Proceedings of the Chemical Society of Japan, Vol.94th, No.3, Page.825 (2014)

  However, when the nanocomposite particles of Non-Patent Document 1 are used as oil-water separators, there are concerns about problems such as durability to solvents, and it is difficult to use them as oil-water separators.

  Accordingly, an object of the present invention is to provide composite particles that can be suitably used as an oil / water separator, an industrially advantageous production method thereof, and an oil / water separator using the composite particles.

  As the inventors proceeded with the development of a new functional material using a fluoroalkyl group-containing oligomer, the composite particles containing a condensate obtained by condensing a specific fluoroalkyl group-containing oligomer, talc, and crosslinked polystyrene were used. It has excellent water repellency and lipophilicity and can be suitably used as an oil-water separator. Furthermore, it discovered that it could utilize suitably as an oil-water separator also with respect to the emulsion containing water and oil, and came to complete this invention.

That is, the first invention to be provided by the present invention includes a condensate of a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1), talc and crosslinked polystyrene. Composite 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 are integers of 0 to 10. R ³ , R ⁴ and R ⁵ may be the same or different groups, and R ³ , R ⁴ and R ⁵ are linear or branched alkyl groups having 1 to ⁵ carbon atoms. M is an integer of 2 to 3.)

Further, the second invention to be provided by the present invention is a reaction raw material solution containing a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1), talc, crosslinked polystyrene, and a reaction solvent. A method for producing composite particles, comprising a reaction step of adding an alkali to perform a hydrolysis reaction of the alkoxysilyl group.
(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 are integers of 0 to 10. R ³ , R ⁴ and R ⁵ may be the same or different groups, and R ³ , R ⁴ and R ⁵ are linear or branched alkyl groups having 1 to ⁵ carbon atoms. M is an integer of 2 to 3.)

  A third invention to be provided by the present invention is an oil / water separator characterized by using the composite particles of the first invention.

According to the present invention, composite particles having excellent water repellency and lipophilicity can be provided. The composite particles can be suitably used as an oil-water separator that separates water and oil.
Further, according to the present invention, the composite particles can be provided by an industrially advantageous method.

Schematic which shows one of embodiment which performs oil-water separation using the oil-water separation material of this invention. Schematic which shows one of embodiment which performs oil-water separation using the oil-water separation material of this invention. The photograph at the time of the separation process of the liquid mixture of 1, 2- dichloroethane and water using the filter paper modified with the composite particles of the present invention in Evaluation 1. A photograph of a chromatography column actually used for separation in Evaluation 2. The photograph at the time of the separation process of the treated water 1 using the composite particle | grains of this invention as a filter material in Evaluation 2. The photograph at the time of performing the separation process of the treated water 2 by using the composite particle (a) or Wakogel C-500HG (b) of the present invention as the filter material in Evaluation 2.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
The composite particle according to the present invention is a condensate obtained by condensing a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the general formula (1) (hereinafter also referred to as “fluoroalkyl group-containing oligomer”), It contains talc and crosslinked polystyrene.

  The composite particles according to the present invention are preferably obtained by performing a reaction step in which an alkali is added to a reaction raw material solution containing a fluoroalkyl group-containing oligomer, talc, crosslinked polystyrene, and a reaction solvent to perform a hydrolysis reaction.

The fluoroalkyl group-containing oligomer according to the reaction step is represented by the following general formula (1) and has a hydrolyzable alkoxysilyl group.
(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 are integers of 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 alkyl groups having 1 to ⁵ carbon atoms. M is an integer of 2 to 3.)

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

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 a pentyl group. Etc.
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 0-10, preferably 0-3. In particular, R ¹ and R ² are preferably —CF (CF ₃ ) OC ₃ F ₇ .

  The fluoroalkyl group-containing oligomer represented by the general formula (1) is produced, for example, by reacting a trialkoxyvinylsilane such as trimethoxyvinylsilane with a fluoroalkanoyl peroxide (for example, JP-A-2002-338691, JP, 2010-77383, A).

Talc (Mg ₃ Si ₄ O ₁₀ (OH) ₂ ) related to the reaction step is a component mainly imparting excellent lipophilicity to the composite particles of the present invention.

  As the talc, it is preferable to use a fine talc from the viewpoint of producing fine composite particles, and the average particle diameter determined by the dynamic light scattering method is preferably 5 to 1000 nm, and more preferably 20 to 500 nm. In the present invention, a commercially available talc can be suitably used.

  The crosslinked polystyrene according to the reaction step is used for imparting durability to a solvent and excellent oil / water separation ability to the composite particles of the present invention.

  In the present invention, cross-linked polystyrene means monovinyl aromatic compounds such as styrene, vinyl xylene, vinyl naphthalene, chloromethyl styrene, and polyvinyl aromatic compounds such as divinyl benzene, divinyl toluene, divinyl xylene, divinyl naphthalene, trivinyl benzene, and the like. Is a cross-linked copolymer.

  As the physical properties of the crosslinked polystyrene, it is preferable to use fine ones from the viewpoint of producing fine composite particles. Fine cross-linked polystyrene is often aggregated, and it is difficult to measure the particle size of primary particles, but the average particle size of secondary particles obtained by a laser light scattering method is 0.1 to 500 μm, Preferably, it may be 5 to 200 μm. In the present invention, a commercially available product can be suitably used as the crosslinked polystyrene.

  As the reaction solvent for the reaction step, a solvent capable of dissolving the fluoroalkyl group-containing oligomer is used. Examples of the reaction solvent in the reaction step include lower alcohols such as methanol, ethanol and isopropyl alcohol, and among these, methanol is particularly preferable.

  In the reaction step of the present invention, when preparing the reaction raw material solution, the order in which the fluoroalkyl group-containing oligomer, talc and crosslinked polystyrene are mixed with the reaction solvent is not particularly limited.

  The content of talc in the reaction raw material solution is a value converted to 100 mg of the fluoroalkyl group-containing oligomer represented by the general formula (1), and is 1 to 500 mg, preferably 20 to 300 mg. When the content of the talc in the reaction raw material solution is in the above range, the lipophilicity and water repellency are excellent.

  The content of the crosslinked polystyrene in the reaction raw material solution is a value converted to 100 mg of the fluoroalkyl group-containing oligomer represented by the general formula (1), and is 5-800 mg, preferably 10-500 mg. When the content of the cross-linked polystyrene in the reaction raw material solution is in the above range, durability and oil / water separation ability are excellent.

  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. For example, the alkali includes ammonium hydroxide. Sodium hydroxide or potassium hydroxide, and ammonium hydroxide is preferred because of its high reactivity.

  The mixing amount of the alkali added to the reaction raw material solution is not particularly limited and is appropriately selected. Moreover, the reaction temperature at the time of hydrolyzing the alkoxysilyl group in a fluoroalkyl group containing oligomer by mixing an alkali with a reaction raw material solution is -5-50 degreeC, Preferably it is 0-30 degreeC. If the reaction temperature is less than −5 ° C., the hydrolysis rate of the alkoxysilyl group becomes too slow, so that the reaction efficiency is poor, and if it exceeds 50 ° C., the dispersion stability of the composite particles tends to be low. The reaction time when the reaction raw material solution is mixed with an alkali to hydrolyze the alkoxysilyl group is not particularly limited and is appropriately selected, but is preferably 1 to 72 hours, and particularly preferably 1 to 72 hours. 24 hours.

  And by performing a reaction process, the composite particle which has a siloxane bond as a main skeleton produces | generates, and the reaction liquid containing the composite particle which concerns on this invention is obtained.

  After completion of the reaction, the solvent is removed under reduced pressure by a conventional method, and if necessary, purification such as washing is performed to obtain composite particles.

  In the present invention, the reaction liquid containing the composite particles can be used as it is as a modifying liquid for modifying various base materials for use as an oil-water separator as described later.

  Moreover, as another preferable physical property of the composite particles of the present invention, the average particle size determined by a dynamic light scattering method is preferably 0.1 to 500 μm, and preferably 10 to 250 μm. When the average particle diameter is within the above range, it is preferable in terms of good dispersibility in various dispersion solvents, resin materials, various base materials and the like.

  The oil-water separator according to the present invention is characterized by using the composite particles.

  Water and oil can be separated by bringing the oil / water separator according to the present invention into contact with a mixed liquid containing water and oil.

The composite particles of the invention can be used, for example, as an oil / water separator by the following two methods.
(1) A method of modifying a base material insoluble in water with the composite particles of the present invention.
(2) A method in which the composite particle itself of the present invention is used as it is as a filter medium.

  As the base material according to (1), an inorganic substance or an organic substance that is insoluble in water can be used. Examples of the inorganic substance include glass fiber, silica, silica gel, alumina, slag wool, molecular sieve, zeolite, activated carbon, diatomaceous earth, sand, asbestos and the like. The organic substance may be a natural polymer or a synthetic polymer. Examples of the natural polymer include cellulose, wool, cotton, silk and the like. Examples of synthetic polymers include condensation-type or addition-type polymer polymers such as polyurethane, polyethylene terephthalate, nylon, and polycarbonate, and ethylenically unsaturated polymer polymers such as polyethylene, polypropylene, vinyl chloride, and vinyl acetate. It is done.

  In addition, the shape of the substrate is not particularly limited, and examples thereof include a strip shape, a sponge shape, a ribbon shape, a fibril shape, a web shape, a mat shape, a cotton cloth shape, and a non-woven cloth shape.

  In the present invention, a commercially available filter paper or the like may be used as a base material for modifying. In this case, the pore diameter of the filter paper is preferably 5 μm or less, and preferably 0.1 to 3 μm from the viewpoint of efficient oil / water separation.

  In the above (1), the method for modifying the base material with the composite particles of the present invention is not particularly limited as long as the composite particles of the present invention can be fixed or supported on the surface or inside of the base material. A known method can be used. As an example, there is a method in which a base material is brought into contact with a dispersion liquid in which the composite particles of the present invention are dispersed at a concentration of 1 to 50 wt% and then dried. Further, the contact between the dispersion and the substrate can be performed by a method of immersing the substrate in the dispersion, a method of spraying the substrate by spraying, a method of applying the dispersion to the substrate, or the like.

  In addition, as the dispersion liquid in which the composite particles are dispersed, the reaction liquid containing the composite particles after the completion of the reaction may be used as it is.

  FIG. 1 is a schematic view showing an embodiment in the case where a mixed solution of water and oil is separated using a filter paper modified with the composite particles of the present invention.

In the embodiment shown in FIG. 1, a simple separation system (A) comprising a column (1b) and a modified filter paper (1a) is provided, and the modified filter paper (1a) is modified with the composite particles of the present invention. It is.
By biting the modified filter paper (1a) in the middle of the column (1b), the mixed liquid (1) of water and oil charged into the column (1b) comes into contact with the modified filter paper (1a). Since oil (1 ′) passes through the modified filter paper (1a) and water cannot pass through the modified filter paper (1a), water and oil can be separated. If necessary, the separation operation can be performed under pressure or under reduced pressure in order to increase the separation efficiency. In this case, the oil (1 ′) may first pass through the modified filter paper (1a), and then the water may be delayed by the strong external force to pass through the modified filter paper (1a). Before elution, water and oil can be separated through the filter paper (1a) modified by means such as finishing the oil-water separation operation.

FIG. 2 is a schematic view showing one embodiment in the case where a mixed liquid of water and oil is separated using the composite particles of the present invention as a filter medium.
In the embodiment shown in FIG. 2, a simple separation system (B) comprising a filter medium layer (2a) including a column (2b) and a filter medium (2c) is provided.
The column (2b) is filled with the composite particles of the present invention as a filter medium (2c) to form a filter medium layer (2a). By putting the mixed liquid (1) of water and oil into the column (2b), the filter medium (2c) and the mixed liquid can be brought into contact with each other. Since oil (1 ′) passes through the filter medium layer (2a) and water cannot pass through the filter medium layer (2a), water and oil can be separated. If necessary, the separation operation can be performed under pressure or under reduced pressure in order to increase the separation efficiency. Moreover, in order to suppress clogging etc., the layer which filled the filter aid in the upper part and / or lower part of the filter material layer (2a) can be provided if needed.

  The filter aid that can be used is not particularly limited and widely known ones can be used. For example, diatomaceous earth, sand particles, pearlite, anthracite, cellulose, wool, cotton, silk, carbonaceous filter aid, acid clay, bentonite, celite, talc, mica, kaolinite, etc. may be mentioned. Two or more types can be used.

  The mixed liquid of water and oil to be treated with the oil / water separator according to the present invention may be in a solution state or an emulsion.

  The oil / water separator according to the present invention can be used for, for example, wastewater treatment containing oil, means for separating or purifying water and oil at production sites in various industrial fields, and the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
<Fluoroalkyl group-containing oligomer sample>
As the fluoroalkyl group-containing oligomer (hereinafter referred to as “VM”), those shown in Table 1 below were used.
In Table 1, the molecular weight is a number average molecular weight determined by gel permeation chromatography (GPC, polystyrene conversion).

{Examples 1 to 4}
VM (100 mg) was dissolved in 5 ml of methanol solution, 100 mg of talc (Asada Flour Mills average particle size; 131 nm) and cross-linked polystyrene in the amount shown in Table 2 (Tokyo Chemical Industry average particle size: 92 μm) were added, Next, a 25 wt% aqueous ammonia solution (2 ml) was added, and the mixture was stirred with a magnetic stirrer at room temperature (25 ° C.) for 1 hour to obtain a reaction solution sample.
After completion of the reaction, the solvent was removed from the reaction solution sample under reduced pressure, and the resulting crude product was dispersed in methanol overnight. Subsequently, the target product was separated as a solid content by centrifugation, the obtained solid content was washed several times with methanol, and after removing the solvent, vacuum-dried at 50 ° C. to obtain the target product (composite particle sample). .
Moreover, the obtained composite particle sample was measured by FT-IR.
IR (KBr, cm ⁻¹ ); 1600 (polystyrene), 1338, 1240 (C—F), 1016 (Si—O—Si), 750 (C—C), 1687 (C═C)

{Comparative Examples 1-2}
A reaction solution sample and a composite particle sample were obtained by performing the reaction under the same reaction conditions as in Example 1 except that the reaction was performed without adding talc or crosslinked polystyrene.

<Evaluation of physical properties>
The average particle diameter and the contact angle between dodecane and water were measured for the composite particles prepared above.
In addition, the average particle diameter and the contact angle of dodecane and water were measured as follows.
(Evaluation of average particle size)
The obtained composite particles were redispersed in methanol and measured using a particle size meter (SALD-200 V manufactured by Shimadzu).
(Evaluation of contact angle between dodecane and water)
A glass plate is immersed in the reaction solution sample obtained in each of the examples and comparative examples for 1 minute at room temperature (25 ° C.), the glass plate is pulled up, and then naturally dried and further vacuum-dried overnight for modified glass. Plate samples were prepared. The contact angle of dodecane and water on the surface of the modified glass plate sample was evaluated using Drop Master 300 made by Kyowa Interface Science. The results are shown in Table 3.
The contact angle was evaluated as a value 30 minutes after dropping water and dodecane.
Moreover, what was processed only with VM was made into the blank 1, and what was processed only with the talc was evaluated as the blank 2, and the evaluation result was written together in Table 3.

(Evaluation as oil / water separator)
Evaluation 1;
A filter paper (Advantec: 131, pore size: 3 μm) cut into a 3 cm square was immersed in the reaction liquid sample obtained in Example 1 for 1 minute at room temperature (25 ° C.). A modified filter paper sample was prepared by vacuum drying.
The water-oil separation using this modified filter paper was examined using 2 ml of a mixed solution of 1,2-dichloroethane and water (1: 1 vol.). The water in the mixture was colored blue with copper sulfate pentahydrate.
In addition, the same evaluation was performed for the case of using filter paper that was not subjected to the modification treatment.

(Result of evaluation 1)
As shown in FIG. 3, a modified filter paper sample was sandwiched between funnels, and a water-oil separation test was performed by filtering the mixed solution under reduced pressure. The results of Evaluation 1 are shown in Table 4. The symbols in Table 4 indicate the following.
○: Water is not visually observed in the filtrate.
Δ: Some water is visually observed in the filtrate.
X: A lot of water is visually observed in the filtrate.
Further, as shown in FIG. 3, by filtering the mixed liquid under reduced pressure using a modified filter paper sample, only 1,2-dichloroethane passes through the modified filter paper, and water and 1,2-dichloroethane are separated. We were able to.
On the other hand, when the mixed solution was filtered under reduced pressure using filter paper that was not subjected to modification treatment, both water and 1,2-dichloroethane passed through the filter paper, so that water and 1,2-dichloroethane could be separated. There wasn't.

Evaluation 2;
A chromatographic column (inner diameter: 10 mm) is packed with sea sand to a layer thickness of about 2 mm, then 200 mg of composite particles obtained in Example 1 (layer thickness: about 4 mm) are packed, and sea sand is further formed thereon. Was packed to a layer thickness of about 2 mm (see FIG. 4). Note that “Rf— (VM—SiO 2) n —Rf / Talc / Pst” in FIG. 4 represents composite particles.
Using this chromatography column, a water-oil separation test was performed on the following two types of treated water.
Further, a test using Wakogel C-500HG in place of the composite particles was similarly tested.
Treated water 1 (mixed solution);
2 ml of a mixed liquid (1: 1 vol.) Of 1,2-dichloroethane and water was prepared. The water in the mixed solution was colored blue with copper sulfate pentahydrate.
Treated water 2 (emulsion);
1,2-dichloroethane (5 ml), water (0.05 ml) and Span 80 (20 mg) as an emulsifier were mixed to prepare an emulsion.

(Result of evaluation 2)
The results of Evaluation 2 are shown in Table 5. The symbols in Table 5 indicate the following.
○: Water is not visually observed in the filtrate.
Δ: Some water is visually observed in the filtrate.
X: A lot of water is visually observed in the filtrate. Alternatively, an emulsion is observed in the filtrate visually.
Further, as shown in FIG. 5, by filtering the treated water 1 under reduced pressure using the composite particles of the present invention as a filter medium, only 1,2-dichloroethane passes through the filter medium layer, 2-Dichloroethane could be separated.
On the other hand, when the treated water 1 was treated with Wakogel C-500HG as a filter medium, it was confirmed visually that some water was mixed in the filtrate after filtration in addition to 1,2-dichloroethane.

Moreover, as shown to Fig.6 (a), only the 1, 2- dichloroethane passes a filter medium layer by filtering the treated water 2 under reduced pressure using the composite particle | grains of this invention as a filter medium, and an emulsion. Water and 1,2-dichloroethane could be separated from each other.
On the other hand, as shown in FIG. 6 (b), when the treated water 2 is treated with Wakogel C-500HG as a filter medium, it passes through the filter medium layer together with the emulsion, and water and 1,2-dichloroethane are passed from the emulsion. Could not be separated.

Claims (7)

A composite particle comprising a condensate of a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1), talc and crosslinked polystyrene.
(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 are integers of 0 to 10. R ³ , R ⁴ and R ⁵ may be the same or different groups, and R ³ , R ⁴ and R ⁵ are linear or branched alkyl groups having 1 to ⁵ carbon atoms. M is an integer of 2 to 3.) ^2. The composite particle according to claim ^1, wherein R ¹ and R ² in the formula (1) are —CF (CF ₃ ) OC ₃ F ₇ .   The composite particle according to any one of claims 1 and 2, wherein an average particle diameter is 0.1 to 500 µm. An alkali is added to a reaction raw material solution containing a fluoroalkyl group-containing oligomer having an alkoxysilyl group represented by the following general formula (1), talc, crosslinked polystyrene and a reaction solvent, and the alkoxysilyl group is hydrolyzed. A method for producing composite particles, comprising a reaction step.
(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 are integers of 0 to 10. R ³ , R ⁴ and R ⁵ may be the same or different groups, and R ³ , R ⁴ and R ⁵ are linear or branched alkyl groups having 1 to ⁵ carbon atoms. M is an integer of 2 to 3.)   An oil / water separator using the composite particles according to any one of claims 1 to 3.   An oil / water separation method according to claim 5, wherein a mixed liquid containing water and oil is brought into contact with the oil / water separator.   An oil-water separation method according to claim 5, wherein the oil-water separator is brought into contact with an emulsion containing water and oil.