JP5473340B2 - INORGANIC OXIDE PARTICLES WITH POLYMERIZATION INITIAL GROUP, PROCESS FOR PRODUCING THE SAME, POLYMER-MODIFIED INORGANIC OXIDE PARTICLES OBTAINED BY USING THE INORGANIC OXIDE PARTICLE, AND PROCESS FOR PRODUCING THE SAME - Google Patents

Description

The present invention relates to inorganic oxide particles with a polymerization initiating group and a method for producing the particles. Furthermore, the present invention provides polymer-modified inorganic oxide particles obtained using the inorganic oxide particles and a method for producing the particles.

Conventionally, metal oxide particles have been used as pigments, ultraviolet absorbers, fillers and the like in paints, inks, resin compositions, cosmetics and the like. However, since such inorganic oxide particles have low dispersibility in an organic solvent that is poorly compatible with water, there is a problem that the particles are likely to aggregate.
As means for solving such problems, for example, as described in Patent Document 1, a number of methods for treating the surface of metal oxide particles with organopolysiloxane and other methods for treating with organosilicon compounds are proposed. Has been.

On the other hand, graft polymerization onto a solid surface has been attempted as a method for changing the surface characteristics of the solid. Patent Document 2 describes a graft surface modified solid obtained by graft polymerizing a polymer chain via a polymerization initiating group imparted to a solid surface.
Patent Document 3 discloses a metal oxide composite powder obtained by polymerizing a monomer having a polymerizable unsaturated group via a polymerization initiating group introduced on the surfaces of zinc oxide, titanium oxide and cerium oxide. Cosmetics containing this powder are described.
Furthermore, Non-Patent Document 1 discloses a sulfonyl chloride compound containing trichloromethanesulfonyl chloride as a useful polymerization initiator.

JP 2002-220540 A JP 1999-263819 JP 2005-290036 A

Chemical Reviews, 2001, Vol.101, No. 9, Page 2934

  The surface treatment method described in Patent Document 1 is useful as a technique for hydrophobizing inorganic oxide particles, but there has been a demand for development of a new technique that can further enhance the effect. Further, the graft surface-modified solid described in Patent Document 2 is obtained by graft polymerization of an organic compound on the solid surface, and it was necessary to further develop this into graft polymerization on the surface of inorganic oxide particles. . Furthermore, although the cosmetics described in Patent Document 3 introduce a polymerization initiator group using a specific polymerization initiator on the surface of zinc oxide, titanium oxide or the like, the types of these polymerization initiators and polymerization initiator groups It has been demanded to further improve the introduction method and the like to enhance the effect.

Moreover, the polymerizable initiator used in Patent Document 2 and Patent Document 3 has a hydrophobic group and a hydrophilic group. On the other hand, a polymerization initiator such as a sulfonyl chloride compound described in Non-Patent Document 1 as a polymerizable initiator has no hydrophilic group, but its application method is not particularly described.

Therefore, the present inventors have repeated intensive research, and as a result of irradiating the dispersion containing the inorganic oxide particles and the polymerization initiator with ultrasonic waves, polymerization initiator groups are formed on the surface of the inorganic oxide particles. If the inorganic oxide particles with a polymerization initiating group can be obtained, and the surface of the inorganic oxide particles with a polymerization initiating group is modified with a polymer compound obtained from a living radical polymerization reaction of a polymerizable monomer. The inventors have found that polymer-modified inorganic oxide particles having excellent hydrophobicity can be obtained, and have completed the present invention.

The inorganic oxide particles with a polymerization initiating group according to the present invention are obtained by irradiating a dispersion containing inorganic oxide particles having a specific surface area of 8 m ² / g or more and a polymerization initiator with ultrasonic waves. It is characterized by being provided with a polymerization initiating group on the surface of the product particles.
The inorganic oxide particles preferably have a hydroxyl group on the surface.
Moreover, it is preferable that the specific surface area of the said inorganic oxide particle is 9-300 m < ² > / g.

The inorganic oxide particles are preferably oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, cerium, and silicon.
The inorganic oxide particles are preferably those in which the surfaces of oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, and cerium are coated with silica.
Further, the inorganic oxide particles are obtained by coating the surface of oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, and cerium with alumina, and then coating with silica. It is preferable that

The polymerization initiator is preferably a sulfonyl chloride compound having a chlorine-substituted alkyl group or a bromine-substituted alkyl group at the terminal.
The sulfonyl chloride compound is preferably at least one selected from trichloromethanesulfonyl chloride, tribromomethanesulfonyl chloride, trichloromethylphenylsulfonyl chloride, and tribromomethylphenylsulfonyl chloride.

The dispersion medium of the dispersion is preferably an aprotic organic solvent.
Moreover, it is preferable that the irradiation amount of the said ultrasonic wave exists in the range of 100,000-2 million J.
Further, the polymerization initiating group is preferably a chlorosulfonyl group represented by —SO ₂ Cl.

The method for producing an inorganic oxide particle with a polymerization initiation group according to the present invention is a method for producing an inorganic oxide particle with a polymerization initiation group by providing a polymerization initiation group on the surface of the inorganic oxide particle,
(1) A step of dispersing the inorganic oxide particles and the polymerization initiator in an aprotic organic solvent,
(2) A step of irradiating the dispersion obtained in the step (1) with ultrasonic waves,
(3) A step of filtering the dispersion obtained in the step (2) to separate a solid content,
(4) The method includes a step of drying the solid content obtained in the step (3).

The inorganic oxide particles preferably have a hydroxyl group on the particle surface and have a specific surface area of 8 m ² / g or more.
Moreover, it is preferable that the polymerization initiator used by the said process (1) is a sulfonyl chloride compound which has a chlorine substituted alkyl group or a bromine substituted alkyl group at the terminal.
Furthermore, the ultrasonic irradiation in the step (2) is preferably performed for 10 to 90 minutes using ultrasonic waves having a frequency of 16 to 200 kHz and an output of 50 to 600 W.

The polymer-modified inorganic oxide particle according to the present invention is obtained by modifying the surface of the inorganic oxide particle with a polymerization initiating group according to any one of the above with a polymer compound obtained from a living radical polymerization reaction of a polymerizable monomer. It is characterized by becoming.
The polymerizable monomer is preferably at least one selected from a (meth) acrylic monomer, a styrene monomer, and a γ-glycidoxy monomer.

The method for producing the polymer-modified inorganic oxide particles according to the present invention includes:
(1) A step of replacing the inside of the reactor equipped with a stirrer dried under reduced pressure with an inert gas,
(2) a step of introducing the inorganic oxide particles with a polymerization initiating group and bipyridyl and / or a bipyridyl derivative into the reactor;
(3) introducing an inert gas into the reactor and maintaining the reactor in an inert gas atmosphere;
(4) introducing an aprotic organic solvent into the reactor,
(5) introducing the polymerizable monomer into the reactor with stirring;
(6) A step of stirring the mixed solution in the reactor at room temperature for 0.5 to 2 hours,
(7) introducing copper chloride into the reactor,
(8) The inorganic liquid is a polymer compound obtained by conducting a living radical polymerization reaction of the polymerizable monomer by heating the mixed liquid in the reactor to a temperature of 60 to 80 ° C. and stirring for 1 to 48 hours. Modifying the surface of the oxide particles;
(9) introducing water into the reactor while stirring and further stirring for 0.5 to 1 hour to stop the living radical polymerization reaction;
(10) Ammonia water and water as necessary are added to the reactor, and after stirring for 0.5 to 1 hour, the mixture is left standing and discharged from the system to be contained in the mixed solution. Removing copper ions,
(11) Add cation exchange resin into the reactor, stir for 0.5 to 1 hour, and then leave to stand to discharge the supernatant out of the system, thereby removing copper ions contained in the mixture. And (12) separating and removing the cation exchange resin, and then drying the solid content.

The inert gas is preferably nitrogen gas.
The aprotic organic solvent is preferably at least one selected from tetrahydrofuran, dioxane, xylene, toluene, and benzene.
Furthermore, the polymerizable monomer is preferably at least one selected from a (meth) acrylic monomer, a styrene monomer, and a γ-glycidoxy monomer.

The inorganic oxide particles with a polymerization initiating group according to the present invention are provided with a polymerization initiating group on the surface of the inorganic oxide particles by irradiating the dispersion containing the inorganic oxide particles and the polymerization initiator with ultrasonic waves. Therefore, the polymer-modified inorganic oxide particles obtained by modifying the polymerization initiating group with a polymer compound have high dispersibility in an organic solvent that is poorly compatible with water, and particle aggregation occurs. It has the characteristic of being difficult.

In the method for producing inorganic oxide particles with a polymerization initiating group according to the present invention, the polymerization initiating group contained in the polymerization initiator having only a hydrophobic group, particularly a polymerization initiator having a methyl halide group, is formed by ultrasonic irradiation. It can be applied directly to the surface. Furthermore, although it depends on the ultrasonic irradiation conditions, the decomposition of the polymerization initiator itself can be kept low. This reduces the amount of by-products generated by the reaction between the polymerization initiator and the inorganic oxide particles as compared with the prior art, and therefore there are fewer factors that hinder the polymerization reaction when preparing the polymer-modified inorganic oxide particles. As a result, the product yield can be increased. Furthermore, since the degree of polymerization of the polymer compound that modifies the surface of the inorganic oxide particles can be easily controlled, the yield of products having desired characteristics can be increased. Therefore, desired polymer-modified inorganic oxide particles can be efficiently prepared.

It is a chart which shows the result of the FT-IR spectrum obtained by measuring the yellow iron oxide particle with a polymerization initiation group prepared in Example 5 using a Fourier transform infrared spectrophotometer. As a reference, the FT-IR spectrum of the yellow iron oxide particles before adding the polymerization initiating group is also shown. It is the photograph (SEM photograph) of the magnification of 300000 times which the silica covering yellow iron oxide particle prepared in Example 4 was taken with the scanning electron microscope. 3 is a photograph (SEM photograph) of magnification 300,000 times of the polymer-modified yellow iron oxide particles prepared in Example 4, taken with a scanning electron microscope.

Hereinafter, the inorganic oxide particles with a polymerization initiating group according to the present invention, the production method thereof, the polymer compound-modified inorganic compound particles obtained using the inorganic oxide particles, and the production method thereof will be specifically described.

[Inorganic oxide particles with polymerization initiation group]
The inorganic oxide particles with a polymerization initiating group according to the present invention impart a polymerization initiating group to the surface of the inorganic oxide particles by irradiating the dispersion containing the inorganic oxide particles and the polymerization initiator with ultrasonic waves. It will be.

Inorganic oxide particles The inorganic oxide particles are not particularly limited, but are preferably those having a hydroxyl group on the particle surface. This is because, when preparing inorganic oxide particles with a polymerization initiating group by ultrasonic treatment described later, a hydroxyl group present on the particle surface reacts with a polymerization initiator to give a polymerization initiating group to the surface of the particle. Because it is considered to be. Therefore, it is considered that the larger the amount of hydroxyl groups present on the surface of the inorganic oxide particles, the better. However, at this time, it is difficult to accurately determine the amount of hydroxyl groups present on the particle surface, and therefore it is not possible to define the lower limit of hydroxyl groups sufficient to cause the above reaction.

More specifically, the inorganic oxide particles are preferably oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, cerium, and silica. As such metal oxide particles, commercially available particles may be used as they are, or those produced by a known method may be used. Examples of iron include commercially available red iron oxide (Fe ₂ O ₃ , bengara), yellow iron oxide (FeO (OH)), black iron oxide (Fe ₃ O ₄ ), and the like. Among these, red iron oxide and yellow iron oxide have many hydroxyl groups on their surfaces, and thus the above reaction (that is, the reaction between the hydroxyl group and the polymerization initiator) is likely to occur.

The surface of the inorganic oxide particles, for example, oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, and cerium is preferably coated with silica. This is because a large number of the hydroxyl groups are present on the surface of silica coated on the particle surface. Furthermore, by this silica coating, when the polymer-modified inorganic oxide particles prepared by the method described later are dispersed in an organic solvent having poor compatibility with water, the transparency of the dispersion can be enhanced.

The method for coating the surface of the inorganic oxide particles with silica is not particularly limited as long as the surface of the inorganic oxide particles can be uniformly coated with silica. For example, the inorganic oxide particles There is a method in which an aqueous silicic acid solution and aqueous ammonia are simultaneously added to an aqueous dispersion containing, followed by dehydration and polycondensation reaction of silicic acid. Further, the organosilicon compound may be hydrolyzed in the presence of ammonia.
As such silica-coated inorganic oxide particles, commercially available particles may be used as they are, for example, Sympholite RW, Sympholite WW, Concerite (both are registered trademarks) manufactured by JGC Catalysts & Chemicals Co., Ltd. Can be mentioned.

The average particle diameter of the inorganic oxide particles is preferably in the range of 10 nm to 10 μm, preferably 100 nm to 5 μm. Here, it is not preferable that the average particle diameter is less than 10 nm because the scattering force of the particles is increased and the handling becomes difficult. On the other hand, when the average particle diameter exceeds 10 μm, the natural sedimentation force increases and it becomes difficult to uniformly disperse in the solvent. These inorganic oxide particles may be those adjusted to particles of an appropriate size by pulverization using a sample mill, sand mill, jet mill, juicer mixer, yary pulverizer or the like.

The shape of the inorganic oxide particles is not particularly limited, and can be selected from those having a shape such as a needle shape, a spherical shape, a rod shape, and a plate shape according to the use and effect. As for the average particle diameter, there are cases where individual measurement conditions (for example, (length in the longitudinal direction + length in the lateral direction) / 2) are indicated depending on the shape, but in the present invention, It means a value measured using a laser diffraction / scattering particle size distribution measuring device or a centrifugal sedimentation particle size distribution measuring device described in “Measurement method and evaluation method” described later.

The specific surface area of the inorganic oxide particles, 8m ² / g or more, preferably it is desirable 9~300m ² / g, more preferably from 10 to 40 m ² / g. Here, when the specific surface area is less than 8 m ² / g, when there are few hydroxyl groups on the surface of the inorganic oxide particles, polymerization initiation groups may not be sufficiently imparted to the particle surface, which is not preferable. In addition, when the specific surface area of the inorganic oxide particles exceeds 300 m ² / g, the mechanical strength of the inorganic oxide particles decreases. Since it may collapse, it is not preferable. However, when such a problem can be avoided, a material having a specific surface area exceeding 300 m ² / g may be used.

Further, when the specific surface area of the inorganic oxide particles is less than 8 m ² / g and a desired amount of a polymerizable initiating group cannot be introduced on the particle surface, the inorganic oxide particles are selected from, for example, iron, titanium, zinc, and cerium. The surface of at least one metal element oxide particle or composite oxide particle is subjected to an alumina coating treatment to increase the specific surface area, and then the silica coating treatment is performed thereon to form an amount of hydroxyl groups present on the particle surface. It is preferable to increase the amount.
The alumina coating treatment includes, for example, adding aluminum sulfate to the aqueous dispersion containing the inorganic oxide particles under an alkaline pH condition or adding ammonium aluminate to the aqueous dispersion containing the inorganic oxide particles under a neutral pH condition. It can be performed by a method such as adding to an aqueous dispersion. Moreover, the said silica coating process can employ | adopt the method similar to the above.

Polymerization initiator The polymerization initiator is not particularly limited as long as it has a structure having a chlorine-substituted alkyl group or a bromine-substituted alkyl group at the terminal and a polymerization initiator at the other terminal. Can do. However, as such a polymerization initiator, it is preferable to use a sulfonyl chloride compound having a chlorine-substituted alkyl group or a bromine-substituted alkyl group at the terminal. Here, the sulfonyl chloride compound means an organic compound having a chlorosulfonyl group represented by —SO ₂ Cl at the terminal.

The number of chlorine or bromine substituted on the alkyl group may be one or more. In addition, a cyclic organic compound such as an aromatic hydrocarbon or an alicyclic hydrocarbon, or an arbitrary organic group such as an alkyl group or an amino group is present between the chlorine-substituted alkyl group or the bromine-substituted alkyl group and the chlorosulfonyl group. May be present. If the structure of such a compound is schematically shown, it is represented by the general formula X-CYZ- (A)-(B) -SO ₂ Cl. Here, X is a halogen, specifically Cl or Br. C is carbon, and Y and Z are chlorine, bromine or hydrogen. Furthermore, A and B are arbitrary organic groups, for example, an unsaturated hydrocarbon group such as an alkyl group or a benzene ring. However, A and B are not necessarily included. The chlorosulfonyl group represented by —SO ₂ Cl is one of the polymerization initiating groups referred to in the present invention.

Among the sulfonyl chloride compounds as the polymerization initiator, those currently available on the market include trichloromethanesulfonyl chloride, tribromomethanesulfonyl chloride, trichloromethylphenylsulfonyl chloride and the like. Among these, it is preferable to use trichloromethanesulfonyl chloride. This trichloromethanesulfonyl chloride is available from Sigma-Aldrich, MP Biomedicals, ICN Biomedicals, ABCR GmbH & Co, Tokyo Chemical Industry Co., Ltd.

Dispersion The dispersion medium of the dispersion is preferably an aprotic organic solvent. The reason is that it has a function of deactivating radical species generated as a by-product when the dispersion medium liquid is irradiated with ultrasonic waves. Moreover, tetrahydrofuran, dioxane, xylene, toluene, benzene etc. are mentioned as said aprotic organic solvent used by this invention. Among these, it is preferable to use tetrahydrofuran.

Inorganic Oxide Particles with Polymerization Initiating Group The inorganic oxide particles with a polymerization initiating group according to the present invention are prepared by irradiating a dispersion containing the inorganic oxide particles and the polymerization initiator with ultrasonic waves.
The polymerization initiator usually does not react with inorganic oxide particles. However, as a result of extensive research by the present inventors, when the dispersion is irradiated with ultrasonic waves, the polymerization initiator reacts with inorganic oxide particles (particularly, hydroxyl groups present on the surface), It has been found that a polymerization initiating group is imparted to the surface of the inorganic oxide particles.
Although the mechanism by which the polymerization initiating group can be imparted to the particle surface in this way is not always clear, the X—C bond contained in the polymerization initiator such as a sulfonyl chloride compound is cleaved by ultrasonic irradiation, and the remaining —CYZ When the -CYZ group at the left end of-(A)-(B) -SO ₂ Cl reacts with an OH group present on the surface of the inorganic oxide particle and chemically bonds, the chlorosulfonyl group that is a polymerization initiating group is inorganic. It is thought that it is introduced into the surface of the oxide particles.

The irradiation amount of the ultrasonic waves is preferably in the range of 100,000 to 2,000,000 J, preferably 150,000 to 1500,000 J. Here, if the irradiation amount is less than 100,000 J, the reactivity between the polymerization initiator and the inorganic oxide particles is lowered, and the surface of the inorganic oxide particles cannot be provided with a polymerization initiating group, or a sufficient amount is provided. Since it may not be able to be given, it is not preferable. On the other hand, when the irradiation amount exceeds 2000000 J, the polymerization initiator is decomposed and a sufficient amount of polymerization initiating groups may not be imparted to the inorganic oxide particles, which is not preferable. Here, the ultrasonic dose (J) is represented by the product (J = WxS) of the ultrasonic output (W) and the irradiation time (S). The unit of the irradiation time (S) is seconds.

The inorganic oxide particles thus obtained have a polymerization initiating group on the surface thereof, which is converted into a KBr tablet method (here, KBr: sample = 100: using a Fourier transform infrared spectrophotometer). FIG. 1 shows the spectrum obtained by measurement using a pellet prepared by mixing at a ratio of 1. Here, a peak appearing in the vicinity of a wave number of 1000 to 1300 cm ^{−1 on} the horizontal axis indicates a polymerization initiating group introduced (provided) on the surface of the inorganic oxide particle, that is, a chlorosulfonyl group.

[Method for producing inorganic oxide particles with polymerization initiation group]
The method for producing an inorganic oxide particle with a polymerization initiation group according to the present invention is a method for producing an inorganic oxide particle with a polymerization initiation group by imparting a polymerization initiation group to the surface of the inorganic oxide particle,
(1) a step of dispersing the inorganic oxide particles and the polymerization initiator in an aprotic organic solvent, (2) a step of irradiating the dispersion obtained in the step (1) with ultrasonic waves,
(3) A step of filtering the dispersion obtained in the step (2) to separate a solid content,
(4) A step of drying the solid content obtained in the step (3) is included.
Next, each step of the manufacturing method will be specifically described as follows.

Process (1)
In this step, inorganic oxide particles and a polymerization initiator are mixed and dispersed in an aprotic organic solvent. Here, the polymerization initiator is preferably dissolved in the organic solvent by sufficiently stirring the mixed solution. As described above, as long as the polymerization initiator is dissolved in an organic solvent, the order of mixing the inorganic oxide particles and the polymerization initiator may be either first or simultaneously.

The polymerization initiator is preferably mixed so as to be in the range of 50 to 250% by weight, preferably 80 to 220% by weight, based on the total weight of the inorganic oxide particles. Here, when the mixing amount of the polymerization initiator is less than 50% by weight, it is difficult to introduce a desired amount of the polymerization initiating group on the surface of the inorganic oxide particles. Moreover, when the mixing amount of the polymerization initiator exceeds 250% by weight, the decomposition reaction of the polymerization initiator proceeds, which is not preferable.

Process (2)
In this step, the dispersion prepared in step (1) is irradiated with ultrasonic waves.
As described above, the ultrasonic irradiation is desirably performed at 100,000 to 2,000,000 J, preferably 150,000 to 1500,000 J.
More specifically, the frequency of the ultrasonic wave is preferably in the range of 16 to 200 kHz. In addition, the frequency of an ultrasonic wave here means the frequency which can be set in the apparatus used for ultrasonic irradiation. That is, in general, a commercially available ultrasonic oscillator oscillates at a plurality of frequencies in proportion to the output, but it means the value of the most frequently oscillated frequency among all the frequencies of the oscillated ultrasonic waves. To do.

In the present invention, the frequency of the ultrasonic wave that can cleave the C—Cl bond of the polymerization initiator is assumed to be a frequency that resonates with vibration of the C—Cl bond, for example, stretching vibration. Since the ultrasonic oscillator oscillates ultrasonic waves having a plurality of frequencies simultaneously, a frequency having the above-described width is set in an apparatus used for ultrasonic irradiation.

Moreover, the irradiation output of the ultrasonic wave is preferably in the range of 50 to 600 W, preferably 100 to 600 W. Here, when the irradiation output is less than 50 W, the reactivity between the surface of the inorganic oxide particles and the polymerization initiator is lowered, and a desired amount of the polymerization initiating group may not be imparted. Moreover, when the said irradiation output exceeds 600 W, since side reaction progress, such as a polymerization initiator decomposition | disassembly, is accelerated, it is unpreferable.

Furthermore, it is desirable that the ultrasonic wave irradiation time be in the range of 10 to 90 minutes, preferably 10 to 70 minutes. Here, if the irradiation time is less than 10 minutes, a desired amount of polymerization initiating groups may not be imparted to the surface of the inorganic oxide particles, which is not preferable. Further, if the irradiation time exceeds 90 minutes, the polymerizable initiator may be decomposed and a desired amount of polymerization initiating groups may not be imparted to the surface of the inorganic oxide particles, which is not preferable.

In the present invention, the content of the inorganic oxide particles is adjusted to the total weight of the dispersion so that the ultrasonic waves can be uniformly applied to the inorganic oxide particles and the polymerization initiator contained in the dispersion. On the other hand, it is desirable to irradiate ultrasonic waves after adjusting the content to 1 to 10% by weight, preferably 1 to 5% by weight. Here, if the content is less than 1% by weight, the product yield per unit operation time decreases, which is not preferable. When the content exceeds 10% by weight, the reactivity between the inorganic oxide particles and the polymerization initiator contained in the dispersion is lowered, and a desired amount of the polymerization initiating group is reduced to the inorganic oxide particles. This is not preferable because it may not be applied to the surface.

Moreover, when irradiating the said ultrasonic wave, it is preferable to adjust the said dispersion liquid to the temperature of 10-30 degreeC, Preferably it is 15-25 degreeC, and is kept at this temperature. Here, when the temperature is lower than 10 ° C., the reaction rate between the hydroxyl group present on the surface of the inorganic oxide particles and the polymerization initiator is remarkably reduced, and work efficiency and production efficiency are reduced. This is not preferable. Moreover, when the said temperature exceeds 30 degreeC, since the decomposition reaction of a polymerization initiator will be accelerated | stimulated, it is unpreferable.

Examples of the ultrasonic irradiation device include commercially available ultrasonic transmission devices, ultrasonic transmitters, circulating ultrasonic irradiation devices, ultrasonic vibrators, ultrasonic cleaners, and the like. Can do. The method of irradiating the dispersion with ultrasonic waves is not particularly limited as long as it can uniformly irradiate the dispersion with ultrasonic waves, and a conventionally known method can be adopted.

Step (3)
In this step, the dispersion containing the polymerization-initiating group-attached inorganic oxide particles obtained in the step (2) is filtered to separate the solid content.
Separation of the solid content composed of the inorganic oxide particles with the polymerization initiating group is performed using a commercially available filtration device such as a Buchner funnel, a filter press, a horizontal belt filter, a synchro filter, a precoat filter, a drum filter, a belt filter, or a tray filter. It can be carried out. As the separation method, a conventionally known method can be adopted, but it is preferably carried out by a vacuum filtration method.
Moreover, it is preferable that the cake-like substance of the inorganic oxide particles with the polymerization initiation group thus obtained is sufficiently washed with an organic solvent such as tetrahydrofuran.

Step (4)
Next, the cake-like substance is dried at room temperature to 60 ° C., preferably at room temperature to 40 ° C., for 0.5 to 3 hours, preferably 0.5 to 1 hour at normal pressure or reduced pressure. preferable. Here, when the drying temperature is less than room temperature, the cake-like substance cannot be sufficiently dried in a short time, and when the drying temperature exceeds 60 ° C., a polymerization initiating group imparted to the particle surface. Is not preferred because it may decompose. In order to dry the cake-like substance of the inorganic oxide particles with polymerization initiating groups at a relatively low temperature and in a short time, it is preferable to carry out by a reduced pressure drying method.
In addition, the dry powder (particle group) of the inorganic oxide particles with polymerization initiation groups obtained in this way is pulverized or pulverized, such as a sample mill, a jet mill, a juicer mixer, or a yary pulverizer, as necessary. It is desirable to pulverize agglomerates and lumps in advance.

[Polymer-modified inorganic oxide particles]
The polymer-modified inorganic oxide particles according to the present invention are obtained by modifying the surface of the above-mentioned inorganic oxide particles with a polymerization initiation group with a polymer compound obtained from a living radical polymerization reaction of a polymerizable monomer.
As the polymerizable monomer, a conventionally known monomer capable of causing a living radical polymerization reaction can be used. However, in the present invention, at least one selected from (meth) acrylic monomers, styrene monomers, and γ-glycidoxy monomers is preferable.

The living radical polymerization reaction is a reaction that does not involve a side reaction that deactivates the end of the polymer, such as a chain transfer reaction or a termination reaction. For this reason, a polymer with uniform length can be obtained, the polymer can be modified again at the end of the polymer, and the high degree of functionality is achieved in that the degree of polymerization is easily controlled and a sharp molecular weight distribution is obtained. It is a polymerization reaction expected in terms of high controllability.
As a result, in the present invention, the surface of the inorganic oxide particles with a polymerization initiating group is reacted with a polymer (polymer compound) having a polymer chain having a uniform length, and has a high hydrophobicity and an organic solvent. It is possible to obtain polymer-modified inorganic oxide particles having excellent dispersibility.

[Method for producing polymer-modified inorganic oxide particles]
The method for producing the polymer-modified inorganic oxide particles according to the present invention includes:
(1) A step of replacing the inside of the reactor equipped with a stirrer dried under reduced pressure with an inert gas,
(2) a step of introducing the inorganic oxide particles with a polymerization initiating group and bipyridyl and / or a bipyridyl derivative into the reactor;
(3) introducing an inert gas into the reactor and maintaining the reactor in an inert gas atmosphere;
(4) introducing an aprotic organic solvent into the reactor,
(5) introducing the polymerizable monomer into the reactor with stirring;
(6) A step of stirring the mixed solution in the reactor at room temperature for 0.5 to 2 hours,
(7) introducing copper chloride into the reactor,
(8) The inorganic liquid is a polymer compound obtained by conducting a living radical polymerization reaction of the polymerizable monomer by heating the mixed liquid in the reactor to a temperature of 60 to 80 ° C. and stirring for 1 to 48 hours. Modifying the surface of the oxide particles;
(9) introducing water into the reactor while stirring and further stirring for 0.5 to 1 hour to stop the living radical polymerization reaction;
(10) Ammonia water and water as necessary are added to the reactor, and after stirring for 0.5 to 1 hour, the mixture is left standing and discharged from the system to be contained in the mixed solution. Removing copper ions,
(11) Add cation exchange resin into the reactor, stir for 0.5 to 1 hour, and then leave to stand to discharge the supernatant out of the system, thereby removing copper ions contained in the mixture. And (12) separating and removing the cation exchange resin, and then drying the solid content.

Examples of the inert gas include nitrogen gas, helium gas, and argon gas. Among these, it is preferable to use nitrogen gas.
The aprotic organic solvent is preferably at least one selected from tetrahydrofuran, dioxane, xylene, toluene, and benzene.
Furthermore, as described above, it is preferable to use at least one selected from a (meth) acrylic monomer, a styrene monomer, and a γ-glycidoxy monomer as the polymerizable monomer.
However, since the above manufacturing method shows one embodiment of the manufacturing method of the polymer-modified inorganic oxide particles according to the present invention, the present invention is not limited to the manufacturing method shown here.

Next, it will be as follows if each process of the said manufacturing method is demonstrated concretely.
Process (1)
In this step, the inside of the reactor equipped with a stirrer that has been dried under reduced pressure is replaced with an inert gas.
As a result, moisture, oxygen, carbon dioxide, etc. affecting the subsequent living radical polymerization reaction can be discharged out of the reactor.
As the stirrer, a stirrer, a stirring bar, a stirring blade, or the like can be used, and a stirring blade is preferably used for uniform stirring.
The inert gas is preferably a gas that does not have the property of stabilizing radicals and that does not react with the polymerization initiator or the inorganic oxide particles. Specifically, as described above, the inert gas does not include oxygen and carbon dioxide, and examples thereof include nitrogen gas, helium gas, and argon gas. Among these, it is preferable to use nitrogen gas.

Process (2)
In this step, the inorganic oxide particles with a polymerization initiating group and bipyridyl and / or a bipyridyl derivative are introduced into the reactor.
The bipyridyl and / or bipyridyl derivative acts as a ligand for the copper component introduced as a catalyst into the reactor in the latter stage, and stabilizes the complex formed from the radical molecule and the copper component generated in the reaction system. It is necessary to make it.
Moreover, it is preferable to introduce | transduce the said bipyridyl and / or bipyridyl derivative (A) so that the molar ratio (A / B) with respect to copper chloride (B) mentioned later may be 5 / 10-25 / 10. Here, when the molar ratio is less than 5/10, it becomes difficult to stabilize the complex, and when the molar ratio exceeds 25/10, bipyridyl or a derivative thereof excessively becomes a living radical reaction. This is not preferable because it may cause a hindrance.

Step (3)
In this step, an inert gas is introduced into the reactor, and the reactor is maintained in an inert gas atmosphere.
As a result, during the operation of the step (2), moisture, oxygen, carbon dioxide and the like mixed in the reactor are discharged out of the reactor to make the system an inert gas atmosphere.
As said inert gas, the said thing can be used and it is preferable to use the same kind as the inert gas used at the said process (1).

Step (4)
In this step, an aprotic organic solvent is introduced into the reactor.
As the aprotic organic solvent, it is preferable to use a solvent having a high dissolving power and a property of suppressing the deactivation of the generated radical molecule, for example, tetrahydrofuran, dioxane, xylene, toluene, benzene and the like. It is done. Among these, it is preferable to use tetrahydrofuran.
In addition, the amount of the aprotic organic solvent introduced is not particularly limited as long as the inorganic oxide particles with polymerization initiator groups and the polymerizable monomer described below can be well dispersed in the organic solvent. It is preferable to introduce into the reactor such an amount that the inorganic oxide particles with polymerization initiating groups are in the range of 1 to 10% by weight with respect to the organic solvent.

Process (5)
In this step, the polymerizable monomer is introduced into the reactor while stirring.
The polymerizable monomer is not particularly limited as long as it is a polymerizable monomer capable of performing a living radical polymerization reaction, and is selected from (meth) acrylic monomers, styrene monomers, and γ-glycidoxy monomers. It is preferable to use at least one selected from the above.

Here, the (meth) acrylic monomer means an acrylic monomer or methacrylic monomer having only one (co) polymerizable double bond in the molecule. The (meth) acrylic monomers include those having a functional group such as a hydroxyl group and a carboxyl group and those having no such functional group, but can be used without particular limitation in the present invention.
Examples of the (meth) acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, and (meth) acrylic. Hexyl acid, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate Alkyl esters of (meth) acrylic acid such as ethyl, (meth) acrylic acid phenoxyethyl, (meth) acrylic acid phenoxydiethylene glycol ester; (meth) acrylic such as (meth) acrylic acid phenyl and (meth) acrylic acid methylphenyl Aryl esters of acids; Carboxyl group-containing monomers such as tonic acid, (anhydrous) maleic acid, fumaric acid; hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate Examples thereof include monomers. Among these, it is preferable to use methyl methacrylate, ethyl methacrylate, butyl methacrylate, or the like.

The styrene monomer means a monomer having one styrene skeleton in the molecule. The styrenic monomer includes those having a functional group such as a hydroxyl group and a carboxyl group, and those having no such functional group, and can be used without particular limitation in the present invention.
Examples of the styrene monomer include halostyrene monomers such as styrene, chlorostyrene, and bromostyrene; alkyl styrene monomers such as methyl styrene and ethyl styrene; functional group-containing styrene that represents a hydroxyl group, a carboxyl group, an ester group, and an amino group. And styrenic monomers such as styrene monomers. Among these, it is preferable to use styrene, 4-methylstyrene, 4-chlorostyrene, or the like.

Furthermore, the γ-glycidoxy monomer means a monomer having one γ-glycidoxy (generally called an epoxy group) skeleton in the molecule. Further, some of these γ-glycidoxy monomers have no functional group, but they can be used without particular limitation in the present invention.
Examples of the γ-glycidoxy monomer include γ-glycidoxymethyl, γ-glycidoxyethyl, γ-glycidoxypropyl, γ-glycidoxybutyl, γ-glycidoxypentyl, and γ-glycidoxy. Γ-glycidoxy alkyls such as hexyl, γ-glycidoxycyclohexyl, γ-glycidoxyheptyl, γ-glycidoxyoctyl, γ-glycidoxynonyl, γ-glycidoxydecyl; γ-glycidoxy Examples include aryl and aryl ethers of γ-glycidoxy such as phenyl, γ-glycidoxymethylphenyl, γ-glycidoxybenzyl, γ-glycidoxyphenylethyl, and γ-glycidoxyphenoxyethyl. Among these, it is preferable to use 1-methoxy-2-methylpropylene oxide, styrene oxide, or the like.

In addition, the polymerizable monomer varies depending on the type and desired polymer modification amount (depending on the amount of the polymerization initiating group imparted to the surface of the inorganic oxide particle), etc. It is preferable to introduce into the reactor so as to be 50 to 200% by weight with respect to the oxide particles. Here, when the introduction amount of the polymerizable monomer is less than 50% by weight, the polymer modification on the surface of the inorganic oxide particles becomes insufficient, and when the introduction amount exceeds 200% by weight, there is no reaction. This is not preferable because it causes a decrease in production efficiency and an increase in production cost, for example, that a polymerizable monomer remains and a step for removing it is required.

Step (6)
In this step, the mixed solution in the reactor is stirred at room temperature for 0.5 to 2 hours.
Thereby, the polymerizable monomer and the inorganic oxide particles with a polymerization initiating group can be well dispersed in the aprotic organic solvent.
The stirring is not particularly limited as long as the polymerizable monomer and the inorganic oxide particles with a polymerization initiating group can be well dispersed in the aprotic organic solvent. It is preferable to carry out over time. Furthermore, it is desirable that the stirring time be adjusted in a timely manner depending on the amount of the polymerizable monomer and the amount of the inorganic oxide particles with the polymerization initiation group.
In this step, it is preferable to stir the mixed solution while flowing the inert gas into the reactor.

Step (7)
In this step, copper chloride is introduced into the reactor.
The copper chloride introduced in this step functions as a catalyst for the living radical polymerization reaction.
Further, the amount of the copper chloride varies depending on the amount of the polymerizable monomer charged and the desired amount of polymer modification (depending on the amount of polymerization initiating groups imparted to the surface of the inorganic oxide particles). It is preferable to introduce into the reactor so as to be 1 to 15% by weight with respect to the inorganic oxide particles with an initiation group. Here, when the introduction amount of the copper chloride is less than 1% by weight, it becomes difficult to uniformly perform the polymerization reaction on the surface of the inorganic oxide particles, and when the introduction amount exceeds 15% by weight, Excessive copper chloride is not preferable because it may inhibit the living radical reaction or stop it in some cases.
In addition, when the said copper chloride is introduce | transduced in a reactor, the living radical polymerization reaction of the said polymerizable monomer will be started from that time, and the color of a liquid mixture will change.

Step (8)
In this step, the liquid mixture in the reactor is heated to a temperature of 60 to 80 ° C. and stirred for 1 to 48 hours, whereby a polymer compound obtained by conducting a living radical polymerization reaction of the polymerizable monomer is used. The surface of inorganic oxide particles is modified.
The heating of the mixed liquid is not particularly limited as long as it can cause a living radical polymerization reaction of the polymerizable monomer and is lower than the boiling point of the aprotic organic solvent to be used. It is preferable to carry out at a temperature of 80 ° C. Here, when the temperature is less than 60 ° C., it is difficult to efficiently cause the living radical polymerization reaction, and when the temperature exceeds 80 ° C., the aprotic organic solvent is easily evaporated. In addition, since the polymerization reaction proceeds excessively and it may be difficult to control the reaction, it is not preferable. Moreover, although the said stirring changes also with the preparation amount of the said polymerizable monomer, the desired polymer modification amount (it depends on the quantity of the polymerization initiating group provided on the surface of the said inorganic oxide particle, etc.) etc., it is 1-48. It is preferable to carry out over time.

Step (9)
In this step, water is introduced into the reactor while stirring, and further stirred for 0.5 to 1 hour to stop the living radical polymerization reaction.
As the water, it is preferable to use pure water obtained by ion exchange treatment. Furthermore, it is preferable to cool the temperature in the reactor to near room temperature before introducing the water.
Further, the water is not particularly limited as long as it is an amount capable of completely stopping the living radical polymerization reaction, but 50 to 50% of the aprotic organic solvent introduced into the reactor. It is preferable to introduce into the reactor so as to be 100% by weight.
Furthermore, in the present invention, the mixed liquid into which the water has been introduced is stirred for 0.5 to 1 hour at room temperature and then left to stand and the supernatant liquid is discharged out of the system (so-called decantation work). It is preferable to keep it. Thereby, a part of copper ion contained in a liquid mixture can be removed previously.

Step (10)
In this step, ammonia water and water as necessary are added to the reactor, and after stirring for 0.5 to 1 hour, the mixture is left to stand and discharged from the system to be contained in the mixed solution. Remove copper ions.
Thereby, the copper component contained in the said liquid mixture can be dissolved and removed in a solvent as an ammonia complex.
Moreover, although the said ammonia water changes also with the density | concentration and the quantity of the copper component contained in a liquid mixture, when using the ammonia water whose ammonia concentration is 15 weight%, the copper chloride introduce | transduced in the liquid mixture is used. Is preferably introduced into the reactor so that the molar ratio (NH ₄ / CuCl) is in the range of 1/1 to 40/1. Moreover, although the said water added as needed changes also with the density | concentrations etc. of the ammonia water to be used, there should just be the quantity which can ionize the said copper component.
Further, in the present invention, the mixed liquid into which the ammonia water has been introduced is stirred for 0.5 to 1 hour at room temperature and then left to stand and the supernatant liquid is discharged out of the system (so-called decantation work). Preferably it is done. Thereby, most of the copper ions contained in the mixed solution can be removed. The operation in this step may be repeated a plurality of times.

Step (11)
In this step, a cation exchange resin is added to the reactor, and after stirring for 0.5 to 1 hour, the mixture is allowed to stand and the supernatant liquid is discharged out of the system to remove copper ions contained in the mixed solution. Remove.
Thereby, the copper ion which could not be removed by the said process (10) can be made to adsorb | suck to a cation exchange resin, and can be removed.
The cation exchange resin is not particularly limited as long as it can sufficiently adsorb the copper ions remaining in the mixed solution, but is calculated from the measured conductivity in the mixed solution. It is preferable to introduce a quantity slightly larger than the quantity into the reactor.
Furthermore, in the present invention, the mixed solution to which the cation exchange resin has been added is stirred for 0.5 to 1 hour at room temperature and then left to stand and the supernatant liquid is discharged out of the system (so-called decantation operation) ) Is preferable. Thereby, copper ions remaining in the mixed solution can be completely or almost completely removed.

Step (12)
In this step, after the cation exchange resin is separated and removed, the solid content is dried.
More specifically, it is as follows.
First, the cation exchange resin is separated and removed by applying the mixed solution obtained in the step (11) to a stainless steel sieve having an opening of 20 μm. Next, the solution is filtered under reduced pressure by a known method using a Buchner funnel and then washed with an organic solvent such as tetrahydrofuran.
Next, the obtained cake-like substance is dried under reduced pressure by a known method to obtain a dry powder of polymer-modified inorganic oxide particles. Furthermore, the aggregate of the dry powder is crushed by a known method using a pulverizer such as a sample mill in order to break up the aggregation of particles generated during drying as necessary.
Thereby, the polymer-modified inorganic oxide particles according to the present invention are obtained.

[Measurement method and evaluation method]
Measurement methods and evaluation methods used in Examples and others of the present invention are shown below.
(1) Measuring method of average particle size (a) Measuring method A of average particle size (Method of measuring with aqueous dispersion)
A slurry liquid (solid content concentration: 1.0% by weight) in which the inorganic oxide particles are dispersed in pure water is prepared, and this is used for 5 minutes using an ultrasonic generator (manufactured by Iuchi, US-2 type). The particles are well dispersed by irradiating ultrasonic waves. Next, the obtained dispersion is subjected to a laser diffraction / scattering particle size distribution measuring device (LA-300 manufactured by Horiba, Ltd.) to measure the particle size distribution of the particles, so that the volume-based cumulative distribution is 50%. Is the average particle diameter (so-called median diameter).

(B) Measuring method B of average particle diameter (method of measuring with organic solvent dispersion)
Slurry liquid in which the inorganic oxide particles, the inorganic oxide particles with polymerization initiation groups, or the polymer-modified inorganic oxide particles are dispersed in hydrogenated polyisobutene (Pearl Ream 4 (registered trademark) manufactured by NOF Corporation). (Solid content concentration 1.0% by weight) was prepared, and this was irradiated with ultrasonic waves for 5 minutes using an ultrasonic crusher device (TA-5287 type ultrasonic breaker manufactured by Kaijo Co., Ltd.). Disperse the particles well. Next, the obtained dispersion is applied to a centrifugal sedimentation type particle size distribution analyzer (CAPA-700 manufactured by Horiba Seisakusho) to measure the particle size distribution of the particles, and the particle size value at which the volume-based integrated distribution is 50%. Is the average particle diameter (so-called median diameter).

(2) Method for Measuring Specific Surface Area About 30 ml of the inorganic oxide particle powder is collected in a magnetic crucible (B-2 type), dried at 105 ° C. for 2 hours, then placed in a desiccator and cooled to room temperature. Next, 1 g of the sample is taken, and the specific surface area of the sample is calculated by a nitrogen adsorption method (here, the BET 1-point method is employed) using a fully automatic surface area measuring device (manufactured by Yuasa Ionics Co., Ltd., Multisorb 12 type).

(3) Measurement method of Fourier transform type infrared spectroscopic spectrum (FT-IR spectrum) Based on KBr tablet method shown in JIS standard, KBr 0.7 g and inorganic oxide particles with polymerization initiation group dried under reduced pressure at room temperature for 3 hours The powder (KBr: sample = 100: 1 mixing ratio) mixed with 0.007 g of the sample was pulverized for 10 minutes in an agate mortar, and then compressed to produce pellets. Next, the obtained pellet is subjected to a Fourier transform infrared spectrometer (JIR-5500, manufactured by JEOL Ltd.) in which the inside of the measurement system is replaced with nitrogen gas, and the FT-IR spectrum is measured.

(4) Dispersibility evaluation method The dispersibility of the polymer-modified inorganic oxide particles is evaluated by polymer-modified inorganic oxidation dispersed in hydrogenated polyisobutene, which is an organic solvent having poor compatibility with water. Evaluation is based on the average particle diameter of the product particles (so-called median diameter). In addition, this average particle diameter is measured based on the measuring method shown to said (1)-(b). Here, the average particle diameter of the polymer-modified inorganic oxide particles after polymer modification (so-called median diameter) from the average particle diameter (so-called median diameter) of the inorganic oxide particles with polymerization initiating groups before polymer modification. The smaller the is, the higher the dispersibility of the polymer-modified inorganic oxide particles in the organic solvent. In addition, as the polymerization initiating groups are imparted to the surface of the inorganic oxide particles at a high density, the modification of the polymer compound on the particle surface is performed uniformly at a high density, so that the individual particles aggregate. It is considered that the dispersibility in the organic solvent is improved by making it hydrophobic at a value close to the particle diameter of the inorganic oxide particles used first. Such polymer-modified inorganic oxide particles having high hydrophobicity can be easily dispersed even in an organic solvent having poor compatibility with water, and cause aggregation of the particles in the organic solvent. Nor.

  Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited to the scope described in these examples.

[Example 1]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group (1) Red iron oxide particles (TAROX R-516P (registered trademark) manufactured by Titanium Industry Co., Ltd., specific surface area 15 m ² / g, in a 3 liter titanium tank 130 g of an average particle size of 1.71 μm measured by A and an average particle size of 3.53 μm measured by measurement method B) was added, and 1170 g of pure water was added so that the solid content concentration would be 10%. Next, a pH meter and a temperature sensor were installed in the titanium tank, and the slurry was stirred for 2 hours at a rotational speed of 330 rpm using a titanium flat blade to obtain the slurry of red iron oxide particles.

Next, after heating the obtained slurry to a temperature of 70 ° C., a 15% strength aqueous ammonia solution was added while stirring the slurry to adjust the pH of the slurry to 9.35. Further, while maintaining the pH of the slurry to 9.35, the silicate solution 276g of 4% strength by weight in terms of SiO ₂ based, was added over 16 hours. Then, the temperature of the slurry was kept at 70 ° C. with stirring and left for 3 hours. Thereby, the surface of the red iron oxide particles was coated with the silica component.

Subsequently, after cooling the temperature of the slurry to room temperature, vacuum filtration was performed using a Buchner funnel. Furthermore, it was washed with 20 times the amount of pure water relative to the weight of red iron oxide.
Next, the obtained cake-like substance was dried at a temperature of 110 ° C. for 18 hours. Furthermore, 140 g of dry powder of red iron oxide particles (hereinafter referred to as “silica-coated red iron oxide particles”) that are crushed by a jet mill to break up the agglomeration of particles generated during drying and are coated with silica. Obtained. The specific surface area of the silica-coated red iron oxide particles thus obtained was 14 m ² / g, and the average particle size measured by the above measuring method B was 2.67 μm.

(2) Put 100 ml of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd., dehydrated product) in a 300 ml glass beaker, add 2 g of trichloromethanesulfonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization initiator, and stir. The polymerization initiator was well dissolved in the organic solvent. Further, 2 g of the silica-coated red iron oxide particles obtained in (1) above was added and stirred well.
Next, using an ultrasonic pulverizer (TA-5287 type ultrasonic breaker manufactured by Kaijo Co., Ltd.) capable of oscillating ultrasonic waves having a frequency of 16 to 200 kHz, the slurry in the beaker installed in the water bath has an output of 150 W. Were irradiated for 30 minutes. At this time, the temperature of the solution in the beaker before ultrasonic irradiation was 20 ° C., and the temperature after ultrasonic irradiation was 21 ° C. At this time, the irradiation amount of the ultrasonic wave was 270000J.

Next, the solid content contained in the slurry was filtered under reduced pressure using a Buchner funnel. Further, the solid content was washed with 200 ml of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd., dehydrated product).
Next, the obtained cake-like substance was dried under reduced pressure for 1 hour at room temperature under a pressure of -0.1 MPa. Further, red iron oxide particles (hereinafter referred to as “red iron oxide particles with a polymerization initiating group”) which are crushed by a sample mill to disaggregate particles generated at the time of drying and are provided with a polymerization initiating group on the surface thereof. 2 g of dry powder was obtained.

When the FT-IR spectrum of the thus obtained polymerization-initiating group-attached red iron oxide particles was measured by the above method, it was derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group. A peak was observed in the vicinity of a wave number of 1000 to 1300 cm ⁻¹ . Thereby, it was confirmed that the polymerization start group was provided to the surface of silica covering red iron oxide.

Preparation of polymer-modified inorganic oxide particles Into a 500 ml three-necked reactor having a dropping tube and a cooling tube and containing a magnetic stirrer, 4 g and 2, red iron oxide particles with a polymerization initiator group, After adding 1.26 g of 2′-bipyridyl (Wako Pure Chemical Industries, Ltd.), deaeration in the reactor and nitrogen substitution were repeated three times.
Next, 350 ml of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd., dehydrated product) and 4 g of n-butyl methacrylate were added to the reactor kept under a nitrogen stream and stirred for 1 hour. Thereafter, 0.4 g of copper chloride (l) (Wako Pure Chemical Industries, Ltd.) was added, the inside of the reactor was heated to a temperature of 75 ° C., stirred for 24 hours, and a polymer obtained from a living radical polymerization reaction of n-butyl methacrylate. The surface of the red iron oxide particles with a polymerization initiating group was modified with a compound.

Next, after the temperature in the reactor was cooled to room temperature, 100 ml of pure water was added with stirring, followed by further stirring for 45 minutes. This stopped the living radical polymerization reaction. Next, after stirring was stopped and allowed to stand, an operation (so-called decantation operation) for discarding the supernatant was performed. Thereafter, 15 g of a 15% strength aqueous ammonia solution and 15 g of pure water were added to the reactor, stirred for 45 minutes, and then allowed to stand and discard the supernatant (so-called decantation). Further, 10 g of cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was added to the reactor and stirred for 45 minutes, and then allowed to stand and discard the supernatant (so-called decantation operation). Thereby, the added copper component was removed.

Next, the cation exchange resin contained in the obtained slurry was removed using a stainless steel sieve having an opening of 20 μm. Subsequently, the solid content contained in the slurry was filtered under reduced pressure using a Buchner funnel. Further, the solid content was washed with 200 ml of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd., dehydrated product).
Next, the obtained cake-like substance was dried under reduced pressure at room temperature under a pressure of -0.1 MPa. Furthermore, red iron oxide particles (hereinafter referred to as “red iron oxide particles”) whose surfaces are modified with a polymer compound obtained from a living radical polymerization reaction of n-butyl methacrylate by pulverizing with a sample mill in order to break up the aggregation of particles generated during drying. 3.9 g of dry powder of “polymer-modified red iron oxide particles”) was obtained. The average particle diameter when the polymer-modified red iron oxide particles thus obtained were dispersed in hydrogenated polyisobutene was measured by the above-mentioned measuring method B and found to be 2.06 μm.

Subsequently, when the polymer-modified red iron oxide particles were observed with a scanning electron microscope (Hitachi High Technology Co., Ltd., S-5500) at a magnification of 300000 times (SEM photograph), silica-coated red iron oxide particles were observed. It was confirmed that the surface of the particle was covered with a film-like polymer compound (hereinafter sometimes referred to as “polymer”).

  The average molecular weight of the polymer covering the surface of the polymer-modified red iron oxide particles was determined by the following method, although it was difficult to determine accurately. That is, in the three-necked reactor, 5 mg of excess trichlorosulfonyl chloride is added in advance, and then the above polymerization reaction is performed. After the reaction is completed, the slurry solution is filtered under reduced pressure, and the free polymer contained in the filtrate is obtained. Was measured by gel permeation chromatography (Showa Denko Co., Ltd. high performance SEC dedicated system ShodexGPC-101 (registered trademark), column: two KF802 and KF803 in series, eluent: tetrahydrofuran) The number molecular weight (Mn) was 6000 to 7000 in terms of polystyrene.

[Example 2]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group In the “Preparation of Inorganic Oxide Particles with Polymerization Initiating Group” described in Example 1, instead of irradiating an ultrasonic wave with an output of 150 W for 30 minutes, an ultrasonic wave with an output of 300 W was applied. Except for irradiation for 30 minutes, 2 g of dry powder of red iron oxide particles with a polymerization initiation group was obtained in the same manner as in Example 1. At this time, the amount of ultrasonic irradiation was 540000 J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization initiation group was provided on the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 2.16 μm. Further, when observed from the SEM photograph of the polymer-modified red iron oxide particles, it was confirmed that the surface of the silica-coated red iron oxide particles was covered with the polymer.
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Example 3]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group At “Preparation of inorganic oxide particles with polymerization initiating group” described in Example 1, red iron oxide particles (TAROXR-516P (registered trademark) manufactured by Titanium Industry Co., Ltd.) Instead of using a specific surface area of 15 m ² / g, an average particle diameter of 1.71 μm measured by the above measurement method A, and an average particle diameter of 3.53 μm measured by the above measurement method B, red iron oxide particles (SunPURO manufactured by Sun Chemical Co., Ltd.) Ammonia aqueous solution is added using Red (registered trademark), specific surface area 11 m ² / g, average particle diameter 0.98 μm measured by measurement method A, and average particle diameter 1.08 μm measured by measurement method B). The silica-coated red iron oxide particles were obtained in the same manner as in Example 1 except that the pH condition was changed from 9.35 to 10. The specific surface area of the silica-coated red iron oxide particles thus obtained was 12 m ² / g, and the average particle size measured by the above measuring method B was 3.26 μm.

Using the silica-coated red iron oxide particles, in the “Preparation of inorganic oxide particles with polymerization initiation group” described in Example 1, the ultrasonic irradiation conditions were as follows: output 150 W, time 30 minutes to output 300 W, time 30 minutes. Except that, 2 g of dry powder of red iron oxide particles with a polymerization initiating group was obtained in the same manner as Example 1. At this time, the amount of ultrasonic irradiation was 540000 J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization initiation group was provided on the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 1.13 μm. Further, when observed from the SEM photograph of the polymer-modified red iron oxide particles, it was confirmed that the surface of the silica-coated red iron oxide particles was covered with the polymer.
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Example 4]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group At “Preparation of Inorganic Oxide Particles with Polymerization Initiating Group” described in Example 1, red iron oxide particles (TAROX R-516P (registered trademark) manufactured by Titanium Industry Co., Ltd.) Instead of using a specific surface area of 15 m ² / g, an average particle diameter of 1.71 μm measured by the above measuring method A, and an average particle diameter of 3.53 μm measured by the above measuring method B, yellow iron oxide particles (SunPURO manufactured by Sun Chemical Co., Ltd.) -Ammonia aqueous solution added using Yellow (registered trademark), specific surface area 16 m ² / g, average particle diameter 2.56 μm measured by measurement method A, average particle diameter 1.49 μm measured by measurement method B) The silica-coated yellow iron oxide particles were obtained in the same manner as in Example 1 except that the pH condition was changed from 9.35 to 10. The specific surface area of the silica-coated yellow iron oxide particles thus obtained was 17 m ² / g, and the average particle size measured by the above measuring method B was 1.83 μm.

Using the silica-coated yellow iron oxide particles, in the “Preparation of inorganic oxide particles with a polymerization initiating group” described in Example 1, the ultrasonic irradiation conditions were as follows: output 150 W, time 30 minutes to output 300 W, time 30 minutes. Except that, 2 g of dry powder of yellow iron oxide particles with a polymerization initiating group was obtained in the same manner as in Example 1. At this time, the amount of ultrasonic irradiation was 540000 J.
Subsequently, when the FT-IR spectrum of the obtained yellow iron oxide particles with a polymerization initiating group was measured by the above method, a peak derived from SO ₂ in a chlorosulfonyl group (—SO ₂ Cl) as a polymerization initiating group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization start group was provided to the surface of the silica covering yellow iron oxide particle.

Preparation of polymer-modified inorganic oxide particles Next, the same method as "Preparation of polymer-modified inorganic oxide particles" described in Example 1, using the yellow iron oxide particles with polymerization initiation groups obtained above Thus, 3.9 g of a dry powder of polymer-modified yellow iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified yellow iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 1.42 μm. Moreover, when observed from the SEM photograph of this polymer-modified yellow iron oxide particle, it was confirmed that the surface of the silica-coated yellow iron oxide particle was covered with the polymer. The results are shown in FIG. 2 (SEM photograph of silica-coated yellow iron oxide particles before polymer modification) and FIG. 3 (SEM photograph of silica-coated yellow iron oxide particles after polymer modification).
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Example 5]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group Using the silica-coated yellow iron oxide particles prepared in Example 4, at the “Preparation of inorganic oxide particles with polymerization initiating group” described in Example 1, a polymerization initiator Example 1 except that the addition amount of trichloromethanesulfonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was increased from 2 g to 4 g, and the ultrasonic irradiation conditions were changed from output 150 W, time 30 minutes to output 300 W, time 60 minutes. Similarly, 2 g of a dry powder of yellow iron oxide particles with a polymerization initiating group was obtained. At this time, the irradiation amount of ultrasonic waves was 1080 000J.
Subsequently, when the FT-IR spectrum of the obtained yellow iron oxide particles with a polymerization initiating group was measured by the above method, a peak derived from SO ₂ in a chlorosulfonyl group (—SO ₂ Cl) as a polymerization initiating group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization start group was provided to the surface of the silica covering yellow iron oxide particle. The obtained FT-IR spectrum is shown in FIG.

Preparation of polymer-modified inorganic oxide particles Next, the same method as “Preparation of polymer-modified inorganic oxide particles” described in Example 1 was performed using the yellow iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of a dry powder of polymer-modified yellow iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified yellow iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and it was 1.52 μm. Moreover, when it observed from the SEM photograph of this polymer modification yellow iron oxide particle, it was confirmed that the surface of the silica covering yellow iron oxide particle is covered with the polymer.
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Example 6]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group Black iron oxide particles (SunPURO-Black (registered trademark) manufactured by Sun Chemical Co., specific surface area 6.7 m ² / g, average measured by the above measuring method A) in a 3 liter titanium tank 130 g of a particle size of 3.74 μm and an average particle size of 4.65 μm measured by the above measuring method B) was added, and 1170 g of pure water was added so that the solid content concentration was 10%. Next, a pH meter and a temperature sensor were installed in a titanium tank, and stirred for 2 hours at a rotational speed of 290 rpm using a titanium flat blade to obtain a slurry of the black iron oxide particles.

Next, after heating the obtained slurry to a temperature of 85 ° C., a 15% strength aqueous ammonia solution was added while stirring the slurry to adjust the pH of the slurry to 7. Further, 55.7 g of 3 wt% ammonium aluminate in terms of Al ₂ O ₃ was added over 2 hours while maintaining the pH of the slurry at 7. Then, the temperature of the slurry was kept at 85 ° C. with stirring for 40 minutes. Thereby, the surface of the black iron oxide particles was coated with the alumina component.

Subsequently, after cooling the temperature of the slurry to room temperature, vacuum filtration was performed using a Buchner funnel. Further, it was washed with 500 ml of 5% aqueous ammonia solution and 1000 ml of pure water.
Next, the obtained cake-like substance was dried at a temperature of 110 ° C. for 18 hours. Further, 129 g of a dry powder of black iron oxide particles (hereinafter referred to as “alumina-coated black iron oxide particles”) crushed by a sample mill to break up the aggregation of particles generated during drying and coated with alumina. Obtained. The alumina coating amount of the alumina-coated black iron oxide particles thus obtained was 2.93% by weight based on the total amount of black iron oxide particles.

Next, the obtained alumina-coated black iron oxide particles were subjected to the same procedure as described in Example 1, “Preparation of inorganic oxide particles with polymerization initiation group”. The surface was coated with silica.
Next, after filtration under reduced pressure and washing under the conditions described in Example 1, the obtained cake-like substance was dried. Further, dry powder of alumina-coated black iron oxide particles (hereinafter, simply referred to as “silica-coated black iron oxide particles”) that has been crushed by a sample mill and coated with silica in order to break up the agglomeration of particles generated during drying. 133 g of body was obtained. The specific surface area of the silica-coated black iron oxide particles thus obtained was 12 m ² / g, and the average particle size measured by the above measuring method B was 4.65 μm.

Next, using the obtained silica-coated black iron oxide particles, a polymerization-initiated group-attached silica was carried out in the same manner as in Example 1 except that the ultrasonic irradiation conditions were changed from an output of 150 W for 30 minutes to an output of 300 W for 30 minutes. 2 g of dry powder of coated black iron oxide particles was obtained. At this time, the amount of ultrasonic irradiation was 540000 J.
Subsequently, when the FT-IR spectrum of the obtained black iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization initiation group was provided on the surface of the silica-coated black iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, using the silica-coated black iron oxide particles with polymerization initiator groups obtained above, the same as "Preparation of polymer-modified inorganic oxide particles" described in Example 1 By the method, 3.9 g of dry powder of polymer-modified black iron oxide particles was obtained.
Next, when the obtained polymer-modified black iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle size was measured by the above-mentioned measuring method B, and was 4.06 μm. Moreover, when observed from the SEM photograph of this polymer-modified black iron oxide particle, it was confirmed that the surface of the silica-coated black iron oxide particle was covered with the polymer.
Furthermore, when the average molecular weight of this polymer was determined by the method described in Example 1, it was 6000 to 7000 in terms of polystyrene.

[Example 7]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group In the “Preparation of Inorganic Oxide Particles with Polymerization Initiating Group” described in Example 1, instead of black iron oxide particles, titanium oxide particles (Ishihara Sangyo Co., Ltd. CR- 50, specific surface area 4.5 m ² / g, average particle diameter 0.62 μm measured by the above measuring method A, and average particle diameter 2.93 μm measured by the above measuring method B). In this method, the surface of the titanium oxide particles was coated with alumina and then with silica. The specific surface area of the alumina-coated titanium oxide particles thus coated with silica (hereinafter simply referred to as “silica-coated titanium oxide particles”) is 13 m ² / g, and the average particle diameter measured by the above-mentioned measuring method B is It was 2.97 μm.

Next, using the obtained silica-coated titanium oxide particles, in the section “Preparation of inorganic oxide particles with polymerization initiation group” described in Example 1, the ultrasonic irradiation conditions were output 150 W, output time 30 minutes to 300 W, Except for the time of 30 minutes, in the same manner as in Example 1, 2 g of a dry powder of titanium oxide particles with a polymerization initiation group was obtained. At this time, the amount of ultrasonic irradiation was 540000 J.
Subsequently, when the FT-IR spectrum of the obtained titanium oxide particles with a polymerization initiating group was measured by the above method, the peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiating group had a wave number. It was recognized near 1000-1300 cm ⁻¹ . Thereby, it was confirmed that the polymerization initiation group was provided on the surface of the silica-coated titanium oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, using the titanium oxide particles with a polymerization initiating group obtained above, in the same manner as "Preparation of polymer-modified inorganic oxide particles" described in Example 1 3.9 g of a dry powder of polymer-modified titanium oxide particles was obtained.
Subsequently, when the obtained polymer-modified titanium oxide particles were dispersed in hydrogenated polyisobutene, the average particle size was measured by the above-mentioned measuring method B, and it was 1.58 μm. Further, when observed from the SEM photograph of the polymer-modified titanium oxide particles, it was confirmed that the surface of the silica-coated titanium oxide particles was covered with a polymer.
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Example 8]
Preparation of inorganic oxide particles with polymerization initiating groups Using the silica-coated red iron oxide particles prepared in Example 3, "Preparation of inorganic oxide particles with polymerization initiating groups" described in Example 1 Then, 2 g of dry powder of red iron oxide particles with a polymerization initiating group was obtained in the same manner as in Example 1 except that the ultrasonic irradiation conditions were changed to output 300 W, time 30 minutes to output 300 W, and time 15 minutes. At this time, the irradiation amount of the ultrasonic wave was 270000J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization initiation group was provided on the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle size was measured by the above-mentioned measuring method B, and found to be 1.22 μm. Further, when observed from the SEM photograph of the polymer-modified red iron oxide particles, it was confirmed that the surface of the silica-coated red iron oxide particles was covered with the polymer.
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Example 9]
Preparation of inorganic oxide particles with polymerization initiating groups Using the silica-coated red iron oxide particles prepared in Example 3, "Preparation of inorganic oxide particles with polymerization initiating groups" described in Example 1 Then, 2 g of dry powder of red iron oxide particles with a polymerization initiating group was obtained in the same manner as in Example 1 except that the ultrasonic irradiation conditions were changed to output 300 W, time 30 minutes to output 300 W, and time 60 minutes. At this time, the amount of ultrasonic irradiation was 1080 000J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization initiation group was provided on the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 2.18 μm. Further, when observed from the SEM photograph of the polymer-modified red iron oxide particles, it was confirmed that the surface of the silica-coated red iron oxide particles was covered with the polymer.
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Example 10]
Preparation of inorganic oxide particles with polymerization initiating groups Using the silica-coated red iron oxide particles prepared in Example 3, "Preparation of inorganic oxide particles with polymerization initiating groups" described in Example 1 Then, 2 g of dry powder of red iron oxide particles with a polymerization initiating group was obtained in the same manner as in Example 1 except that the ultrasonic irradiation conditions were 150 W for output, 30 minutes to 300 W for output, and 90 minutes for time. At this time, the irradiation amount of the ultrasonic wave was 1620000J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. It was recognized in a weak state near a wave number of 1000 to 1300 cm ⁻¹ . This confirmed that a part of the polymerization initiation group was imparted to the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 2.98 μm. When observed from SEM photographs of the polymer-modified red iron oxide particles, it was found that the polymer adhered to a part of the surface of the silica-coated red iron oxide particles.

[Example 11]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group Red iron oxide particles used in Example 3 (Sun Chemical, SunPURO-Red (registered trademark), specific surface area 11 m ² / g, average particle diameter measured by measurement method A 0 .98 μm, red iron oxide particles with a polymerization initiating group were used in the same manner as in Example 1 except that red iron oxide particles whose surface had an average particle diameter of 1.08 μm measured by the measurement method B) were not coated with silica. 2 g of dry powder of particles was obtained.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization initiation group was provided on the surface of the red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Next, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 1.05 μm. Moreover, when observed from the SEM photograph of this polymer modified red iron oxide particle, it was confirmed that the surface of the red iron oxide particle was covered with the polymer.
Furthermore, when the average molecular weight of this polymer was determined by the method described in Example 1, it was 6000 to 7000 in terms of polystyrene.

[Example 12]
Preparation of Inorganic Oxide Particles with Polymerization Initiating Group Yellow Iron Oxide Particles Used in Example 4 (SunPuro-Yellow (registered trademark) manufactured by Sun Chemica, specific surface area 16 m ² / g, average particle diameter 2 measured by the above-mentioned measurement method A) .56 μm, yellow iron oxide with a polymerization initiating group, in the same manner as in Example 1 except that yellow iron oxide particles whose surface was measured by the measurement method B and whose average particle diameter was 1.49 μm were not coated with silica. 2 g of dry powder of particles was obtained.
Subsequently, when the FT-IR spectrum of the obtained yellow iron oxide particles with a polymerization initiating group was measured by the above method, a peak derived from SO ₂ in a chlorosulfonyl group (—SO ₂ Cl) as a polymerization initiating group was found. A wave number of 1000-1300 cm ⁻¹ was observed. Thereby, it was confirmed that the polymerization initiating group was provided on the surface of the yellow iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, the same method as "Preparation of polymer-modified inorganic oxide particles" described in Example 1, using the yellow iron oxide particles with polymerization initiation groups obtained above Thus, 3.9 g of a dry powder of polymer-modified yellow iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified yellow iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle size was measured by the above-mentioned measuring method B, and was 1.00 μm. Moreover, when observed from the SEM photograph of this polymer modified yellow iron oxide particle, it was confirmed that the surface of the yellow iron oxide particle was covered with the polymer.
Furthermore, when the average number molecular weight of this polymer was calculated | required by the method as described in Example 1, it was 6000-7000 on the polystyrene conversion basis.

[Comparative Example 1]
Preparation of inorganic oxide particles with polymerization initiating groups Using the silica-coated red iron oxide particles prepared in Example 3, "Preparation of inorganic oxide particles with polymerization initiating groups" described in Example 1 Then, 2 g of dry powder of red iron oxide particles with a polymerization initiating group was obtained in the same manner as in Example 1 except that the ultrasonic irradiation conditions were changed to 150 W for output, 30 minutes to 300 W for output, and 5 minutes for time. At this time, the irradiation amount of the ultrasonic wave was 90000J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. It was recognized in a fairly weak state near a wave number of 1000 to 1300 cm ⁻¹ . Thereby, it was confirmed that the polymerization initiation group was hardly provided on the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 6.19 μm. However, when observed from SEM photographs of the polymer-modified red iron oxide particles, almost no polymer was formed on the surface of the silica-coated red iron oxide particles.

[Comparative Example 2]
Preparation of inorganic oxide particles with polymerization initiating groups Using the silica-coated red iron oxide particles prepared in Example 3, "Preparation of inorganic oxide particles with polymerization initiating groups" described in Example 1 Then, 2 g of dry powder of red iron oxide particles with a polymerization initiating group was obtained in the same manner as in Example 1 except that the ultrasonic irradiation conditions were 150 W for output, 30 minutes to 300 W for output, and 120 minutes for time. At this time, the irradiation amount of the ultrasonic wave was 216000J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. It was not recognized in the vicinity of wave numbers 1000 to 1300 cm ⁻¹ . Thereby, it was confirmed that the polymerization initiation group was hardly provided on the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 4.38 μm. Further, when observed from the SEM photograph of the polymer-modified red iron oxide particles, it was not recognized that the surface of the silica-coated red iron oxide particles was covered with the polymer.

[Comparative Example 3]
Preparation of inorganic oxide particles with polymerization initiating groups Using the silica-coated red iron oxide particles prepared in Example 3, "Preparation of inorganic oxide particles with polymerization initiating groups" described in Example 1 Then, 2 g of dry powder of red iron oxide particles with a polymerization initiating group was obtained in the same manner as in Example 1 except that the ultrasonic irradiation conditions were changed to output 150 W, time 30 minutes to output 75 W, time 30 minutes. At this time, the irradiation amount of the ultrasonic wave was 135000J.
Subsequently, when the FT-IR spectrum of the obtained red iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. It was not recognized in the vicinity of wave numbers 1000 to 1300 cm ⁻¹ . Thereby, it was confirmed that the polymerization initiation group was hardly provided on the surface of the silica-coated red iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the red iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of dry powder of polymer-modified red iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified red iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle size was measured by the above-mentioned measurement method B, and was 3.17 μm. However, when observed from SEM photographs of the polymer-modified red iron oxide particles, almost no polymer was formed on the surface of the silica-coated red iron oxide particles.

[Comparative Example 4]
Preparation of inorganic oxide particles with polymerization initiating group Titanium oxide particles used in Example 7 (CR-50 manufactured by Ishihara Sangyo Co., Ltd., specific surface area 4.5 m < ² > / g, measured by measurement method A) Polymerization started in the same manner as in Example 7 except that titanium oxide particles having an average particle diameter of 0.62 μm and an average particle diameter of 2.93 μm measured by the above measuring method B were not coated with alumina and silica silica. 2 g of dry powder of titanium oxide particles with base was obtained. At this time, the amount of ultrasonic irradiation was 540000 J.
Subsequently, when the FT-IR spectrum of the obtained titanium oxide particles with a polymerization initiating group was measured by the above method, the peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiating group had a wave number. It was not recognized in the vicinity of 1000 to 1300 cm ⁻¹ . Thereby, it was confirmed that the polymerization initiation group was hardly provided on the surface of the titanium oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, using the titanium oxide particles with a polymerization initiating group obtained above, in the same manner as "Preparation of polymer-modified inorganic oxide particles" described in Example 1 3.9 g of a dry powder of polymer-modified titanium oxide particles was obtained.
Subsequently, when the obtained polymer-modified titanium oxide particles were dispersed in hydrogenated polyisobutene, the average particle size was measured by the above-mentioned measuring method B, and it was 4.50 μm. However, when observed from SEM photographs of the polymer-modified titanium oxide particles, almost no polymer formation was observed on the surface of the titanium oxide particles.

[Comparative Example 5]
Preparation of inorganic oxide particles with polymerization initiating group Black iron oxide particles used in Example 6 (SunPURO-Black (registered trademark) manufactured by Sun Chemical Co., specific surface area of 6.7 m < ² > / g, measured by method A) The same procedure as in Example 6 was used, except that black iron oxide particles whose surface had an average particle diameter of 3.74 μm and an average particle diameter of 4.65 μm measured by the measurement method B were not coated with alumina and silica. Thus, 2 g of a dry powder of black iron oxide particles with a polymerization initiating group was obtained. At this time, the amount of ultrasonic irradiation was 540000 J.
Subsequently, when the FT-IR spectrum of the obtained black iron oxide particles with a polymerization initiation group was measured by the above method, a peak derived from SO ₂ in the chlorosulfonyl group (—SO ₂ Cl) as the polymerization initiation group was found. It was not recognized in the vicinity of wave numbers 1000 to 1300 cm ⁻¹ . Thereby, it was confirmed that the polymerization start group was hardly provided on the surface of the black iron oxide particles.

Preparation of polymer-modified inorganic oxide particles Next, a method similar to "Preparation of polymer-modified inorganic oxide particles" described in Example 1 using the black iron oxide particles with polymerization initiating groups obtained above. Thus, 3.9 g of a dry powder of polymer-modified black iron oxide particles was obtained.
Subsequently, when the obtained polymer-modified black iron oxide particles were dispersed in hydrogenated polyisobutene, the average particle diameter was measured by the above-mentioned measuring method B, and was 6.70 μm. However, when observed from SEM photographs of the polymer-modified black iron oxide particles, almost no polymer was observed on the surface of the black iron oxide particles.

[Comparative Example 6]
Preparation of silicon-treated red iron oxide particles Red iron oxide particles used in Example 1 (TAROX R-516P (registered trademark) manufactured by Titanium Industry Co., Ltd., specific surface area 15 m ² / g, average particle measured by the above-mentioned measurement method A 20 g of a diameter of 1.71 μm and an average particle size of 3.53 μm measured by the above measuring method B) is put in a sample mill, and 0.2 g of silicone oil (KF-99-6cs manufactured by Shin-Etsu Chemical Co., Ltd.) is added thereto Stir for 3 minutes. Next, the obtained silicon-treated red iron oxide particles were baked at a temperature of 150 ° C. for 15 hours, and then crushed by a sample mill again to break up the aggregation of particles generated during the calcination. Obtained.
The average particle diameter when the silicon-treated red iron oxide particles thus obtained were dispersed in hydrogenated polyisobutene was measured by the above-mentioned measuring method B, and was 6.50 μm.

In order to facilitate the comparison, Table 1 below shows the results of collecting the main parts of the contents described in Examples 1 to 12 and Comparative Examples 1 to 6.
As is apparent from this result, in the case of the polymer-modified inorganic oxide particles shown in Examples 1 to 12, the average particle size of the particles in the hydrogenated polyisobutene than the inorganic oxide particles before modification with the polymer compound It was found that the diameter was getting smaller. As a result, it was confirmed that the hydrophobicity of the particles was increased, and the dispersibility in an organic solvent (ie, hydrogenated polyisobutene) was improved.
On the other hand, in the case of the polymer-modified inorganic oxide particles shown in Comparative Examples 1 to 5 (however, the surface of many particles is hardly modified with a polymer compound), the inorganic material before modification with the polymer compound is used. It has been found that the average particle diameter of the particles is larger than that of the oxide particles, or hardly changed. This is because when the surface of the inorganic oxide particles with polymerization initiating groups is modified, the solution is under acidic conditions, and the Si-O-Si bond on the solid surface is cleaved to form a Si-OH bond. It is thought that it comes from. Furthermore, in the case of the silicon-treated red iron oxide particles shown in Comparative Example 6, it was found that the average particle diameter of the particles was larger than that of the red iron oxide particles before the silicone oil treatment.
Since this employs a resin coating method, the possibility of coating a plurality of particles together at the time of coating is high, and it is derived from not coating individual particles as in the present invention. Conceivable. Thereby, it was confirmed that the dispersibility in an organic solvent (namely, hydrogenated polyisobutene) was not good.

Claims (16)

In a dispersion liquid containing inorganic oxide particles having a specific surface area of 8 m ² / g or more and a sulfonyl chloride compound having a chlorine-substituted alkyl group or a bromine-substituted alkyl group as a terminal as a polymerization initiator , the irradiation amount is 150,000 to 2,000,000 J Inorganic with a polymerization initiating group, characterized in that a chlorosulfonyl group represented by —SO ₂ Cl, which is a polymerization initiating group , is imparted to the surface of the inorganic oxide particles by irradiating ultrasonic waves in the range of Oxide particles.   The inorganic oxide particles with a polymerization initiating group according to claim 1, wherein the inorganic oxide particles have a hydroxyl group on the surface. The specific surface area of the said inorganic oxide particle is 9-300 m < ² > / g, The inorganic oxide particle with a polymerization initiation group of Claim 1 or Claim 2 characterized by the above-mentioned.   The inorganic oxide particles are oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, cerium, and silicon. Inorganic oxide particles with a polymerization initiating group described in 1.   The inorganic oxide particles are obtained by coating the surfaces of oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, and cerium with silica. The inorganic oxide particle with a polymerization initiation group in any one of 1-3. The inorganic oxide particles are obtained by coating the surface of oxide particles or composite oxide particles of at least one metal element selected from iron, titanium, zinc, and cerium with alumina, and then coating with silica. The inorganic oxide particle with a polymerization initiating group according to any one of claims 1 to 3. Any the sulfonyl chloride compound, trichloromethane sulfonyl chloride, tribromomethane chloride, trichloromethyl phenyl sulfonyl chloride, according to claim 1, wherein the at least one selected from tribromomethylphenyl chloride polymerization initiation group with the inorganic oxide particles according to any. The dispersion medium of the dispersion, the polymerization initiation group with the inorganic oxide particles according to any one of claims 1 to 7, characterized in that a non-protonic organic solvents. A method for producing an inorganic oxide particle with a polymerization initiating group by providing a polymerization initiating group on the surface of the inorganic oxide particle,
(1) A step of dispersing the inorganic oxide particles and a sulfonyl chloride compound having a chlorine-substituted alkyl group or a bromine-substituted alkyl group as a polymerization initiator in an aprotic organic solvent,
(2) A step of irradiating the dispersion obtained in the step (1) with an ultrasonic wave having a frequency of 16 to 200 kHz and an output of 100 to 600 W for 10 to 90 minutes ,
(3) A step of filtering the dispersion obtained in the step (2) to separate a solid content,
(4) The manufacturing method of the inorganic oxide particle with a polymerization start group including the process of drying solid content obtained by the said process (3). The said inorganic oxide particle has a hydroxyl group on particle | grain surface, and the specific surface area is a thing of 8 m < ² > / g or more, Production of the inorganic oxide particle with a polymerization initiation group of Claim 9 characterized by the above-mentioned. Method. A polymer modification obtained by modifying the surface of the inorganic oxide particles with a polymerization initiating group according to any one of claims 1 to 8 with a polymer compound obtained from a living radical polymerization reaction of a polymerizable monomer. Inorganic oxide particles. The polymer-modified inorganic oxide particles according to claim 11 , wherein the polymerizable monomer is at least one selected from a (meth) acrylic monomer, a styrene monomer, and a γ-glycidoxy monomer. A method for producing the polymer-modified inorganic oxide particles according to claim 11 or 12 ,
(1) A step of replacing the inside of the reactor equipped with a stirrer dried under reduced pressure with an inert gas,
(2) a step of introducing the inorganic oxide particles with a polymerization initiating group and bipyridyl and / or a bipyridyl derivative into the reactor;
(3) introducing an inert gas into the reactor and maintaining the reactor in an inert gas atmosphere;
(4) introducing an aprotic organic solvent into the reactor,
(5) introducing the polymerizable monomer into the reactor with stirring;
(6) A step of stirring the mixed solution in the reactor at room temperature for 0.5 to 2 hours,
(7) introducing copper chloride into the reactor,
(8) The inorganic liquid is a polymer compound obtained by conducting a living radical polymerization reaction of the polymerizable monomer by heating the mixed liquid in the reactor to a temperature of 60 to 80 ° C. and stirring for 1 to 48 hours. Modifying the surface of the oxide particles;
(9) introducing water into the reactor while stirring and further stirring for 0.5 to 1 hour to stop the living radical polymerization reaction;
(10) Ammonia water and water as necessary are added to the reactor, and after stirring for 0.5 to 1 hour, the mixture is left standing and discharged from the system to be contained in the mixed solution. Removing copper ions,
(11) Add cation exchange resin into the reactor, stir for 0.5 to 1 hour, and then leave to stand to discharge the supernatant out of the system, thereby removing copper ions contained in the mixture. And (12) a method for producing polymer-modified inorganic oxide particles, comprising: (12) separating and removing the cation exchange resin and then drying the solid content. The method for producing polymer-modified inorganic oxide particles according to claim 13 , wherein the inert gas is nitrogen gas. The polymer-modified inorganic oxide particles according to claim 13 or 14 , wherein the aprotic organic solvent is at least one selected from tetrahydrofuran, dioxane, xylene, toluene, and benzene. Method. The polymer modification according to any one of claims 13 to 15 , wherein the polymerizable monomer is at least one selected from a (meth) acrylic monomer, a styrene monomer, and a γ-glycidoxy monomer. A method for producing inorganic oxide particles.