Surface-treated inorganic oxide and article

Abstract

To provide a surface-treated inorganic oxide in which the surface of an inorganic oxide such as an inorganic filler or an inorganic pigment is treated with a specific polymer treating agent, and which exhibits enhanced dispersibility, compatibility, and fillability with respect to various media.SOLUTION: Provided is a surface-treated inorganic oxide that is a treated product in which an inorganic oxide is surface-treated with a polymer treating agent. The polymer treating agent is a polymer whose number-average molecular weight is 6,000 to 30,000, including a constitutional unit (1) derived from a monomer 1 represented by general formula (1), a constitutional unit (2) derived from a monomer 2 such as (meth)acryloyloxypropylmethyldimethoxysilane, and an optional constitutional unit (3) derived from a vinyl monomer. (R1 represents a hydrogen atom or a methyl group. A represents O or NH. X represents an ethylene group or a propylene group. Y represents O, NHCOO, or NHCONH. Each R2 independently represents a hydrogen atom or a methyl group. R3 represents an alkyl group having 1 to 18 carbon atoms.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a surface-treated inorganic oxide and an article.

Background Art

[0002] Silane coupling agents having an alkoxysilyl group in their molecular structure are used as surface modifiers for improving physical properties such as wettability, adhesiveness, compatibility, dispersibility, mechanical strength, water resistance, and bleed-out resistance of inorganic oxides such as silica, alumina, titanium oxide, and zinc oxide, and inorganic pigments.

[0003] When the surface of an inorganic oxide is treated with a silane coupling agent, the alkoxysilyl group of the silane coupling agent and the hydroxyl group of the inorganic oxide undergo a dealcoholization reaction and dehydration condensation. Then, the silane coupling agent chemically bonds to the surface of the inorganic oxide, and the silane coupling agent also self-condenses. As a result, the organic group of the silane coupling agent is introduced onto the surface of the inorganic oxide, and the physical properties of the inorganic oxide can be improved depending on the characteristics of the introduced organic group.

[0004] Heretofore, various silane coupling agents for surface-treating inorganic oxides and inorganic oxides such as glass, inorganic fillers, and inorganic pigments surface-treated with silane coupling agents have been proposed (Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, with the further development of technology, in providing a dispersion liquid in which inorganic oxides such as pigments are dispersed in a liquid medium or a composite material in which inorganic oxides are dispersed in a resin, it is required to further improve characteristics such as the dispersibility and compatibility of the inorganic oxides.

[0007] The present invention has been made in view of such problems of the prior art, and the problem to be solved is to provide a surface-treated inorganic oxide in which the surface of an inorganic oxide such as an inorganic filler or an inorganic pigment is treated with a specific polymer treating agent and which has improved characteristics such as dispersibility, compatibility, and filling property in various media. Further, the problem to be solved by the present invention is to provide an article containing this surface-treated inorganic oxide.

Means for Solving the Problem

[0008] That is, according to the present invention, there is provided a surface-treated inorganic oxide shown below. [1] A surface-treated inorganic oxide which is a processed product obtained by surface-treating an inorganic oxide with a polymer treating agent, wherein the polymer treating agent contains 50 to 90% by mass of a structural unit (1) derived from a monomer 1 represented by the following general formula (1), 10 to 50% by mass of a structural unit (2) derived from at least one monomer 2 selected from the group consisting of (meth)acryloyloxypropylmethyldimethoxysilane, (meth)acryloyloxypropyltrimethoxysilane, (meth)acryloyloxypropylmethyldiethoxysilane, and (meth)acryloyloxypropyltriethoxysilane, and 0 to 25% by mass of an arbitrary structural unit (3) derived from a vinyl monomer other than the monomer 1 and the monomer 2, and is a polymer having a number average molecular weight of 6,000 to 30,000.

[0009] TIFF2025093339000001.tif35170(In the general formula (1), R1 represents a hydrogen atom or a methyl group, A represents O or NH, X represents an ethylene group or a propylene group, Y represents O, NHCOO, or NHCONH, R2 independently represents a hydrogen atom or a methyl group, n represents an average number of repeating units of 20 to 100, and R3 represents an alkyl group having 1 to 18 carbon atoms)

[0010] [2] The surface-treated inorganic oxide according to [1] above, wherein the inorganic oxide is inorganic oxide fine particles having an average particle diameter of 10 nm to 100 μm. [3] The surface-treated inorganic oxide according to [2] above, which is a treated product obtained by surface-treating 100 parts by mass of the inorganic oxide fine particles with 0.5 to 50 parts by mass of the polymer treating agent. [4] The surface-treated inorganic oxide according to [2] or [3] above, wherein the inorganic oxide fine particles are at least one selected from the group consisting of titanium dioxide, zinc oxide, silica, alumina, and composite oxide pigments.

[0011] Further, according to the present invention, the following articles are provided. [5] An article containing the surface-treated inorganic oxide according to any one of [1] to [4].[[]END]]

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a surface-treated inorganic oxide in which the surface of an inorganic oxide such as an inorganic filler or an inorganic pigment is treated with a specific polymer treating agent, and the characteristics such as dispersibility, compatibility, and filling property in various media are improved. Further, according to the present invention, it is possible to provide an article containing this surface-treated inorganic oxide.

Embodiments for Carrying Out the Invention

[0013] <Surface-Treated Inorganic Oxide> Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. One embodiment of the present invention is an inorganic oxide surface-treated with a polymer treating agent, which is a treated product obtained by treating the surface of an inorganic oxide with a specific polymer treating agent and introducing a polyalkylene glycol chain derived from the polymer treating agent onto the surface of the inorganic oxide. Hereinafter, the details of the surface-treated inorganic oxide of this embodiment will be described.

[0014] (Polymer treating agent) The polymer treating agent is a polymer containing a structural unit (1) derived from monomer 1 and a structural unit (2) derived from monomer 2, and preferably a polymer further containing an arbitrary structural unit (3) derived from a vinyl monomer other than monomer 1 and monomer 2. Monomer 1 is a macromonomer having a polyalkylene glycol chain represented by the following general formula (1).

[0015] TIFF2025093339000002.tif35170(In the general formula (1), R1 represents a hydrogen atom or a methyl group, A represents O or NH, X represents an ethylene group or a propylene group, Y represents O, NHCOO, or NHCONH, R2 independently represents a hydrogen atom or a methyl group, n represents an average number of repeating units of 20 to 100, and R3 represents an alkyl group having 1 to 18 carbon atoms)

[0016] By introducing the structural unit (1) derived from monomer 1, a polymer having a structure grafted with a polyalkylene glycol chain such as a polyethylene glycol chain, a polypropylene glycol chain, and a polyethylene glycol polypropylene glycol chain can be obtained. Then, by using a polymer having a structure grafted with a polyalkylene glycol chain as a polymer treating agent, a surface-treated inorganic oxide having high compatibility with various dispersion media, excellent dispersibility, and capable of being filled at a high concentration can be obtained.

[0017] At the terminal of the polyalkylene glycol chain, an alkyl group having 1 to 18 carbon atoms (the group represented by R3 in the general formula (1)) is present. The monomer 1 represented by the general formula (1) is a macromonomer obtained by reacting a monoalkoxypolyalkylene glycol chain and a compound having a functional group such as a hydroxyl group or an amino group with a compound having a reactive group that reacts with this functional group and a (meth)acryloyl group. The molecular weight of the monomer 1 is preferably about 1,000 to 4,000. The molecular weight of the monomer 1 is a value converted from the molecular weight of a functional group such as monoalkoxypolyalkylene glycol before the introduction of the (meth)acryloyl group, obtained by nuclear magnetic resonance measurement.

[0018] The monomer 2 is at least one compound (monomer) selected from the group consisting of (meth)acryloyloxypropylmethyldimethoxysilane, (meth)acryloyloxypropyltrimethoxysilane, (meth)acryloyloxypropylmethyldiethoxysilane, and (meth)acryloyloxypropyltriethoxysilane. The monomer 2 is a compound having an alkoxysilyl group in its molecule. When a polymer treating agent containing a structural unit (2) derived from the monomer 2 is used, the hydroxyl groups present on the surface of the inorganic oxide undergo dehydration condensation with the alkoxysilyl group to form a siloxane bond. Thereby, the polymer treating agent binds to the surface of the inorganic oxide, and a surface-treated inorganic oxide (surface-treated inorganic oxide) can be obtained.

[0019] Monomer 3 is a vinyl monomer other than Monomer 1 and Monomer 2 and is copolymerizable with Monomer 1 and Monomer 2. As Monomer 3, it is preferable to use (meth)acrylic acid-based monomers. Specific examples of Monomer 3 include (meth)acrylic acid; monofunctional (meth)acrylates having substituents such as methyl, ethyl, propyl, butyl, amyl, 2-ethylhexyl, isooctyl, nonyl, dodecyl, hexadecyl, octadecyl, isostearyl, behenyl, cyclohexyl, trimethylcyclohexyl, t-butylcyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl, nonylphenoxyethyl, glycidyl, isobornyl, dicyclopentanyl, dicyclopentenyl, dicyclopentenyloxyethyl, isobornyl, dimethylaminoethyl, diethylaminoethyl, and tetrahydrofurfuryl; etc. However, monomers having a hydroxyl group or a carboxy group are likely to react with the alkoxysilyl group present in the molecule of Monomer 2 and may cause gelation or the like, so they are not preferable. Also, monomers such as styrene, vinyltoluene, vinylnaphthalene, vinylcaprolactone, α-methylstyrene, and vinyl acetate can be used as Monomer 3.

[0020] In the polymer treatment agent (polymer), the content of structural unit (1) is 50 to 90% by mass, preferably 55 to 85% by mass. Also, in the polymer treatment agent (polymer), the content of structural unit (2) is 10 to 50% by mass, preferably 15 to 45% by mass. Further, in the polymer treatment agent (polymer), the content of structural unit (3) is 0 to 25% by mass, preferably 0 to 20% by mass. Note that the total of structural unit (1), structural unit (2), and structural unit (3) is 100% by mass. The polymer dispersant is preferably a polymer substantially composed only of structural unit (1), structural unit (2), and optionally used structural unit (3).

[0021] Among the structural units contained in the polymer, the proportion of structural unit (1) is the highest. For this reason, the polyalkylene glycol chains densely present in the polymer cause steric hindrance, suppressing the proximity of the dispersed inorganic oxides to each other and enabling stable dispersion. Also, since the amount of polyalkylene glycol chains in the polymer treatment agent component increases, the compatibility with the dispersion medium is improved, allowing for dispersion at a high concentration. If the content of structural unit (1) is less than 50% by mass, the steric hindrance becomes insufficient and it may become difficult to dissolve in the dispersion medium. On the other hand, if the content of structural unit (1) exceeds 90% by mass, monomer 1 with somewhat low reactivity is likely to remain without polymerization.

[0022] If the content of structural unit (2) is less than 10% by mass, the number of reaction sites (count) between the polymer treatment agent and the inorganic oxide is small, and even if they react and are treated, there is a possibility of physical peeling. On the other hand, if the content of structural unit (2) exceeds 50% by mass, not only does it react with the surface of the inorganic oxide, but it also easily reacts between the polymer treatment agents. For this reason, fixation of the inorganic oxides to each other or solidification due to crosslinking of the polymer treatment agent is likely to occur, and it may become difficult to disperse in the dispersion medium.

[0023] If the content of structural unit (3) exceeds 25% by mass, the proportion of the other structural units relatively decreases, so the function as a polymer treatment agent may easily decline.

[0024] The number average molecular weight of the polymer used as the polymer treatment agent is 6,000 to 30,000, preferably 7,000 to 25,000. If the number average molecular weight of the polymer is less than 6,000, the amount of structural unit (1) derived from monomer 1, which is a macromonomer, decreases, resulting in insufficient dispersibility. On the other hand, if the number average molecular weight of the polymer exceeds 30,000, since the molecular weight is large, the processing amount may increase. The number average molecular weight in this specification is a value in terms of polystyrene measured by gel permeation chromatography (GPC).

[0025] (Method for producing a polymer treatment agent (polymer)) The polymers used as the polymer treatment agent can be produced by conventionally known radical polymerization methods or living radical polymerization methods. Among them, production by the living radical polymerization method is preferable because it can make the molecular weights of the main chains uniform and can form an AB block copolymer by adjusting the monomer addition method.

[0026] As the conventionally known radical polymerization method, a polymerization method for adjusting the molecular weight using a chain transfer agent such as thiol is preferable. As the living radical polymerization method, there are atom transfer radical polymerization (ATRP method), reversible addition-fragmentation chain transfer polymerization (RAFT method), nitroxide method (NMP method), organic tellurium method (TERP method), iodine transfer polymerization (ITP method), reversible transfer catalyst polymerization (RTCP method), and reversible catalyst-mediated polymerization (RCMP method), etc.

[0027] The polymerization conditions and the like are not particularly limited. An azo radical generator, a peroxide radical generator, or the like may be added to the reaction system. The polymerization form may be any of solvent-free, solution polymerization, emulsion polymerization, etc. Among them, solution polymerization is preferable, and solution polymerization using a water-soluble organic solvent is more preferable. The water-soluble organic solvent used in the solution polymerization can be removed by washing with water when treating the inorganic oxide.

[0028] Monomer 1 is a macromonomer that can be obtained by a conventionally known method. Monomer 1 can be obtained, for example, by dehydration condensation of a monoalkoxypolyalkylene glycol and (meth)acrylic acid. Also, in the presence of a base, it can be obtained by reacting a monoalkoxypolyalkylene glycol with (meth)acrylic acid chloride or (meth)acrylic anhydride. Further, it is also possible to react a monoalkoxypolyalkylene glycol with an isocyanate group-containing (meth)acrylate such as (meth)acryloyloxyethyl isocyanate and urethanize to obtain Monomer 1. And it is possible to react a monoalkoxypolyalkylene glycol monoamine with (meth)acrylic acid, (meth)acrylic acid chloride, and (meth)acrylic anhydride, etc., and amidate to obtain Monomer 1. Also, it is possible to react a monoalkoxypolyalkylene glycol monoamine with (meth)acryloylethyl isocyanate and ureaize to obtain Monomer 1.

[0029] (Inorganic oxide) As the inorganic oxide, conventionally known inorganic oxides can be used. Specific examples of the inorganic oxide include silica, alumina, zinc oxide, titanium dioxide, zirconium oxide, iron oxide, copper oxide, yttria, molybdenum oxide, indium oxide, tin oxide, tungsten oxide, bismuth oxide, antimony oxide, and composite oxides thereof; composite oxides of alkali metals such as lithium, sodium, and potassium and alkaline earth metals such as magnesium, strontium, and calcium with metals such as iron, manganese, cobalt, and nickel; composite oxides of metals such as cobalt, chromium, titanium, and aluminum; natural minerals such as clay and mica; etc.

[0030] Examples of the shape of the inorganic oxide include plate-like such as a glass plate, and also amorphous, particulate, etc. Among them, the shape of the inorganic oxide is preferably particulate. That is, the inorganic oxide is preferably inorganic oxide fine particles. By treating the surface of the inorganic oxide fine particles with a specific polymer treating agent, the properties of the inorganic oxide fine particles can be improved.

[0031] Examples of the inorganic oxide fine particles include pigments; plastic fillers; inorganic fillers such as titanium dioxide, zinc oxide, silica, alumina, and composite oxide pigments used as fillers; and the like. By surface-treating these inorganic oxide fine particles with a specific polymer treating agent, properties such as dispersibility, filling property, and fluidity can be improved.

[0032] Examples of the shape of the inorganic oxide fine particles include amorphous, spherical, cubic, rectangular parallelepiped, sugar lump, flat, disc-shaped, conical, plate-shaped, needle-shaped, uneven, and porous. The average particle diameter of the inorganic oxide particles is preferably from 10 nm to 100 μm, and more preferably from 50 nm to 20 μm. The average particle diameter of the inorganic oxide fine particles can be calculated as the average value of the values measured by image processing of an electron micrograph. In the case of a non-spherical shape such as a needle shape, the average value of the major axis and the minor axis is taken as the particle diameter. It can also be measured by the dynamic light scattering method after dispersing in a liquid medium.

[0033] The inorganic oxide may be surface-treated in advance with a surface treating agent other than the aforementioned polymer treating agent. Examples of the surface treatment include inorganic treatments such as silica treatment, alumina treatment, silica-alumina treatment, and zirconia treatment; organic acid treatments such as oleic acid treatment; and conventionally known silane coupling agent treatments and silazane treatments. The amount of the surface treating agent used may be appropriately set according to the amount and surface area of the inorganic oxide. For example, those obtained by surface-treating 100 parts by mass of the inorganic oxide with 0.1 to 5 parts by mass of the surface treating agent can be used.

[0034] (Method for producing surface-treated inorganic oxide) The surface-treated inorganic oxide can be produced by a dry method, a wet method, a coating method, or the like. In the dry method, an inorganic oxide such as inorganic oxide fine particles is put into a tumbler, a high-speed stirrer, a pulverizer, or the like, and the above-mentioned polymer treating agent is added. It is diluted with water or an organic solvent, and if necessary, an acid component such as hydrochloric acid and acetic acid, or an alkali component such as aqueous ammonia and aqueous sodium hydroxide solution is added as a catalyst. The content is stirred and mixed, or sprayed little by little while stirring and mixing to fix the polymer treating agent on the surface of the inorganic oxide. After the treatment, it is preferably dried, more preferably heated to 80 °C or higher and dried, and even more preferably heated to 120 °C or higher and dried. By heating appropriately, the reaction between the surface of the inorganic oxide and the polymer treating agent can be completed. After drying, if necessary, by performing a pulverization treatment, the surface-treated inorganic oxide of the present embodiment can be obtained.

[0035] In addition, in the wet method, the inorganic oxide and the above-mentioned polymer treating agent are mixed in a liquid medium such as water or an organic solvent. If necessary, a dispersion treatment is performed to react the polymer treating agent with the surface of the inorganic oxide. To promote hydrolysis, in addition to water, an aqueous solution of an acid component or an alkali component may be added as a catalyst. To mix the inorganic oxide and the polymer treating agent, a mixer such as a disperser or a homogenizer can be used. As a disperser used in the dispersion treatment, by using a ball mill, a vertical bead mill, a horizontal bead mill, a high-pressure homogenizer, or the like, the particulate inorganic oxide can be reacted with the polymer treating agent in a state where it is finely dispersed up to near the primary particles, and the particulate inorganic oxide can be treated individually.

[0036] The mixed solution containing the treated inorganic oxide (surface-treated inorganic oxide) and the polymer treating agent may be filtered, or coarse particles may be removed using a filter. Next, after precipitation in a poor solvent in which the polyalkylene glycol chain of the polymer treating agent does not dissolve, filtration can be performed to obtain a paste state. For example, when the proportion of propylene glycol units (PO) in the polyalkylene glycol chain is 70% by mass or more, precipitation in water can be used to obtain it in a paste state. Also, by using an evaporator or the like to distill off at least a part of the liquid medium from the mixed solution, a paste state can be obtained. Furthermore, by completely distilling off the liquid medium from the mixed solution, a solid state can also be obtained. Also, by drying while spraying the mixed solution by spray drying or the like, a powder state can be obtained. Also, it can be obtained by solid-liquid separation using a centrifuge. It is preferable to heat and dry the obtained paste, solid, and powder to complete the reaction between the alkoxysilyl group of the polymer treating agent and the hydroxyl group or the like present on the surface of the inorganic oxide. It is preferable to pulverize the obtained dried product with a pulverizer into a powder form as necessary.

[0037] When the shape of the inorganic oxide is plate-like or film-like such as a glass plate, for example, the polymer treating agent or a polymer treating agent solution dissolved in a solvent such as water or an organic solvent is applied or sprayed onto the surface of the inorganic oxide. The content of the surface treating agent in the surface treating agent solution is preferably less than 10% by mass. After applying or spraying the surface treating agent solution, heating to 120°C or higher for drying and curing is preferably performed to complete the reaction between the alkoxysilyl group of the surface treating agent and the hydroxyl group or the like present on the surface of the inorganic oxide. Thereby, the cured film formed by the surface treating agent can be fixed to the surface of the inorganic oxide to obtain the target inorganic oxide.

[0038] <Article> One embodiment of the article of the present invention contains the above-described surface-treated inorganic oxide. As described above, the surface-treated inorganic oxide used in the article of this embodiment is one in which a polyalkylene glycol chain derived from a polymer treatment agent is introduced onto the surface of the inorganic oxide. Therefore, when the introduced polyalkylene glycol chain is a polyethylene glycol chain, the surface of the article is hydrophilic. Accordingly, the article of this embodiment is useful as an article such as glass or a mirror having a functional surface such as antifogging property and frost prevention property.

[0039] Also, when using particulate surface-treated inorganic oxide (surface-treated fine particles), by dispersing the surface-treated fine particles in a liquid medium capable of dissolving the polyalkylene glycol chain bonded to the surface, even if sedimented, due to the effect of preventing particle adhesion by the solvent containing the polyalkylene glycol chain, it is possible to easily return to the original dispersed state substantially only by stirring or the like, and a dispersion liquid excellent in redispersibility can be obtained. Further, by utilizing the ionic conductivity due to the ion doping of this alkylene glycol chain, it can also be used as an active material for lithium ion batteries, semi-solid batteries, and all-solid batteries.

[0040] Note that the surface-treated fine particles can be used as functional fillers or fillers such as paints, inks, and coating agents. For example, by dispersing the surface-treated fine particles in a paint or ink containing a solvent capable of dissolving the polyalkylene glycol chain, paints and inks excellent in dispersibility can be obtained. Also, by blending the surface-treated fine particles as a filler into a coating agent such as an ultraviolet ray / electron beam curable coating agent, a coating agent with a high filling rate and excellent fluidity can be obtained. Furthermore, for thermoplastic resins such as polystyrene, polyester, and polyacrylic, and thermosetting resins such as acrylic resin, melamine resin, epoxy resin, and alkyd resin, the surface-treated fine particles can be filled at a filling rate of, for example, 50% by mass or more, preferably 70% by mass or more, and the fluidity and processability are also good.

Examples

[0041] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are based on mass unless otherwise specified.

[0042] (Synthesis Example 1) (a) Synthesis of Macromonomer 100 parts (0.045 mol) of a mono-methyl ether copolymer of polypropylene glycol and polyethylene glycol (PPG / PEG) with an amino group at one end (trade name "Jeffamine M2005", manufactured by Huntsman Corporation, molecular weight 2222.2 (M2005)) and 100 parts of diethylene glycol dimethyl ether (DMDG) were placed in a reaction vessel and stirred and mixed. A solution containing 6.98 parts (0.045 mol) of 2-isocyanatoethyl methacrylate (trade name "Karenz MOI", manufactured by Resonaas Corporation) (MOI) and 6.98 parts of DMDG was dropped into the reaction vessel over 30 minutes. After the dropping, a part of the reaction solution was sampled, and it was confirmed by infrared spectroscopy (IR) that the isocyanate groups derived from MOI had almost completely disappeared and a urea bond had been formed. Thus, it was confirmed that macromonomer MC-1 was produced. The number average molecular weight (Mn) in terms of polystyrene of macromonomer MC-1 measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as the developing solvent was 3,400, and the dispersity (PDI = Mw (weight average molecular weight) / Mn (number average molecular weight)) was 1.16. Also, an attempt was made to measure the amine value of macromonomer MC-1 using a potentiometric automatic titrator with a 0.1 mol / L 2-propanolic hydrochloric acid solution, but it could not be measured. From this, it was also confirmed that the reaction between M2005 and MOI was complete.

[0043] (b) Synthesis of Polymer (Polymer Treatment Agent) To the above reaction vessel, 35.0 parts of DMDG, 15.0 parts of methyl methacrylate (MMA), 20.0 parts of 3-trimethoxysilylpropyl methacrylate (trade name "KBM-503", manufactured by Shin-Etsu Chemical Co., Ltd.) (M503), and 3.0 parts of 1-dodecanethiol (LSH) were added. After heating to 70 °C while bubbling nitrogen, 2.0 parts of 2,2'-azobis(isobutyronitrile) (trade name "V-601", manufactured by Fujifilm Wako Pure Chemical Corporation) (V-601) were added and polymerized for 4 hours. An additional 0.5 part of V-601 was added and polymerized at 70 °C for 4 hours to form a polymer (polymer treatment agent), and polymer treatment agent solution SG-1 was obtained. The Mn of the formed polymer was 9,200 and the PDI was 1.85. The solid content measured using a moisture meter was 49.7%.

[0044] (Synthesis Examples 2 to 6) Except for using the formulations shown in Table 1, polymer treatment agent solutions SG-2 to SG-6 were obtained in the same manner as in Synthesis Example 1 described above. The meanings of the abbreviations in Table 1 are as shown below. · M41: Mono-end amino-functionalized polypropylene glycol polyethylene glycol monomethyl ether copolymer, trade name "Genamin M41 / 2000", manufactured by Clariant · M1000: Mono-end amino-functionalized polypropylene glycol polyethylene glycol monomethyl ether copolymer, trade name "Jeffamine M1000", manufactured by Huntsman · M3085: Mono-end amino-functionalized polypropylene glycol polyethylene glycol monomethyl ether copolymer, trade name "Jeffamine M3085", manufactured by Huntsman · M502: 3-Methacryloyloxypropylmethyldimethoxysilane, trade name "KBM-502", manufactured by Shin-Etsu Chemical Co., Ltd. · E502: 3-Methacryloyloxypropylmethyldiethoxysilane, trade name "KBE-502", manufactured by Shin-Etsu Chemical Co., Ltd. · E503: 3-Methacryloyloxypropyltriethoxysilane, trade name "KBE-503", manufactured by Shin-Etsu Chemical Co., Ltd. · BzMA: Benzyl methacrylate

[0045] TIFF2025093339000003.tif170170

[0046] (Comparative Synthesis Examples 1 to 3) Except for using the compositions shown in Table 2, the same procedure as in Synthesis Example 1 described above was carried out to obtain polymer treatment agent solutions RSG-1 to 3.

[0047] TIFF2025093339000004.tif212170

[0048] <Production of Surface-Treated Inorganic Oxides (Surface-Treated Fine Particles) (1)> Example 1 100 parts of titanium oxide pigment (product name "R-900", manufactured by Chemours), 80.0 parts of methanol, 20.1 parts of polymer treatment solution SG-1 (10 parts of polymer treatment), 20.0 parts of ion-exchanged water, and 0.1 parts of acetic acid were placed in a resin container. 400 parts of 0.5 mm zirconia beads were filled into the container, and the mixture was shaken for 2 hours using a paint conditioner for dispersion treatment to obtain a pigment dispersion. The pigment dispersion obtained by separating the zirconia beads was poured into a large amount of water, and the resulting precipitate was filtered and washed with ion-exchanged water to obtain a water paste. The obtained water paste was dried in a dryer at 120 ° C. for 12 hours to obtain a lump-shaped dried product. The obtained dried product was pulverized in a grinder to obtain surface-treated fine particles TB-1, which are fine particles of a surface-treated inorganic oxide.

[0049] When the infrared absorption (IR) of the obtained surface-treated fine particles was measured, a peak (1,730 cm) of the carbonyl group derived from the polymer treatment agent was observed. -1 ) and the hydrocarbon peak (2,900 cm -1 A peak near the surface (broad) was confirmed. On the other hand, the peak derived from the ether bond of the polyalkylene glycol chain overlapped with the peak derived from titanium oxide and could not be confirmed. The non-volatile content was measured using a halogen lamp moisture meter and was 99.9%. Furthermore, the inorganic residue was measured by thermal analysis in which the organic matter was burned by heating to 400°C and was 91.5%. From these results, it is believed that a specified amount of polymer treatment agent is bonded to the surface of titanium oxide.

[0050] (Examples 2 to 6, Comparative Examples 1 to 5) Except for using the polymer treatment agent solution or silane coupling agent of the types and amounts shown in Table 3, surface-treated fine particles TB-2 to 6 and RB-1 to 5, which are particulate surface-treated inorganic oxides, were obtained in the same manner as in Example 1 described above. Details of the obtained surface-treated fine particles TB-2 to 6 and RB-1 to 5 are shown in Table 3. The meanings of the abbreviations in Table 3 are shown below. · M573: N-phenyl-3-aminopropyltrimethoxysilane, trade name "KBM-573", manufactured by Shin-Etsu Chemical Co., Ltd. · OTMS: Octadecyltrimethoxysilane

[0051] TIFF2025093339000005.tif122170

[0052] <Evaluation (1)> 100 parts of the surface-treated fine particles of the type shown in Table 4, 33.3 parts of toluene, and 33.3 parts of methyl ethyl ketone were placed in a resin container. The container was filled with 0.5 mm zirconia beads and shaken for 2 hours using a paint conditioner for dispersion treatment to obtain pigment dispersion liquids W-1 to 11. Among the obtained pigment dispersion liquids, for those having fluidity, the viscosity was measured using a B-type viscometer. Also, using a dynamic light scattering type particle size distribution measuring device (trade name "nanoSAQRA", manufactured by Otsuka Electronics Co., Ltd.), the average particle size (median diameter (D 50 )) of the pigment (titanium oxide) in the obtained pigment dispersion liquid was measured. Furthermore, the dispersibility of the pigment dispersion liquid was evaluated according to the evaluation criteria shown below. The results are shown in Table 4. ○: Liquid state, and the average particle size was 300 nm or less. ×: Gel (no fluidity) or thixotropic, and the average particle size was more than 300 nm.

[0053] TIFF2025093339000006.tif86170

[0054] <Production of Surface-Treated Inorganic Oxide (Surface-Treated Fine Particles) (2)> (Example 7) 200 parts of silica sol (trade name "Snowtex ST-O", manufactured by Nissan Chemical Industries, Ltd., 20% silica content, average particle size 12 nm) were placed in a separable flask. 6.0 parts of polymer treatment agent solution SG-5, 200 parts of isopropanol, and 0.5 part of 28% aqueous ammonia were added, and the mixture was heated and reacted for 5 hours while refluxing. 100 parts of propylene glycol monomethyl ether (MPG) were added to the taken-out content, and the volatile components were removed using an evaporator to obtain an MPG dispersion of surface-treated fine particles KB-1. The obtained dispersion was an extremely thin translucent dispersion, and the solid content was 23.8%.

[0055] <Evaluation (2)> 100 parts of pentaerythritol triacrylate (trade name "Aronix M-305", manufactured by Toagosei Co., Ltd.), 31.5 parts of MPG dispersion of surface-treated fine particles KB-1, and 4 parts of a photoinitiator (trade name "Irgacure 2959", manufactured by BASF Japan Ltd.) were mixed to obtain an ultraviolet curable coating agent. The obtained coating agent was applied to a PET film (trade name "Cosmo Shine A4300", manufactured by Toyobo Co., Ltd., film thickness 100 μm) using a bar coater so that the dry film thickness became 3 μm, and then dried at 100 °C for 5 minutes. Irradiated with light using a high-pressure mercury lamp of 80 W / cm so that the integrated light quantity became 300 mJ / cm 2 to cure the coating agent and obtain a coating film. The total light transmittance of the coating film measured using a haze meter was 92.1%, and the haze value was 0.6. No bumps or foreign matters were present, and a coating film excellent in transparency could be formed.

[0056] <Production of Surface-Treated Inorganic Oxide (Surface-Treated Fine Particles) (3)> (Example 8) 500 parts of spherical powder of alumina (average particle size 10 μm, surface untreated), 500 parts of methanol, 25.2 parts of polymer treatment solution SG-1, and 1 part of 28% ammonia water were placed in a tray and mixed and stirred for 30 minutes at 2,000 rpm using a homogenizer to obtain a mixed liquid. The resulting mixed liquid was added to a container containing a large amount of water while stirring. The resulting precipitate was filtered and washed with ion-exchanged water to obtain a water paste. The resulting water paste was dried in a dryer at 120° C. for 12 hours to obtain a lump-shaped dried product. The resulting dried product was pulverized in a grinder to obtain surface-treated fine particles AB-1, which are fine particles of a surface-treated inorganic oxide. The non-volatile content of the resulting surface-treated fine particles AB-1 was 99.9%, and the inorganic residue was 98.8%.

[0057] Comparative Example 5 Surface-treated fine particles RB-6 were obtained in the same manner as in Example 8, except that 2.5 parts of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (trade name "KBM-603", manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of the polymer treatment solution SG-1. The non-volatile content of the obtained surface-treated fine particles RB-6 was 99.9%, and the inorganic residue was 99.7%.

[0058] <Evaluation (3)> (i) 80 parts of spherical powder of alumina (average particle size 10 μm, surface untreated), (ii) 80 parts of surface-treated fine particles AB-1, and (iii) 80 parts of surface-treated fine particles RB-6 were placed in a resin container. 20 parts of epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name jER-871) were added to each and stirred to obtain mixtures (i) to (iii). Mixture (i) was a high-viscosity liquid that barely flowed. Mixture (iii) was a high-viscosity liquid with a viscosity of 15 Pa s. In contrast, mixture (ii) was a low-viscosity liquid with a viscosity of 6.2 Pa s. It is believed that the compatibility between alumina and epoxy resin was improved by the surface treatment, resulting in high loading and improved flowability. [Industrial Applicability]

[0059] By using the polymer treating agent of the present invention, a surface-treated inorganic oxide with improved dispersibility, filling property, fluidity, hydrophilicity, etc. can be produced. And this surface-treated inorganic oxide is useful as a filler or a colorant to be blended in various coating agents and the like, and is expected to be applied to articles used in various fields such as water-based paints, oil-based paints, water-based inks, water-based inkjet inks, solvent-based inkjet inks, ultraviolet curable inkjet inks, semiconductor encapsulants, display members, electronic component members, refractive index control films, heat shielding films, magnetic fluids, battery materials, and phosphors.

Claims

1. A surface-treated inorganic oxide which is a treated product obtained by surface-treating an inorganic oxide with a polymer treating agent, wherein the polymer treating agent contains 50 to 90% by mass of a structural unit (1) derived from a monomer 1 represented by the following general formula (1), 10 to 50% by mass of a structural unit (2) derived from at least one monomer 2 selected from the group consisting of (meth)acryloyloxypropylmethyldimethoxysilane, (meth)acryloyloxypropyltrimethoxysilane, (meth)acryloyloxypropylmethyldiethoxysilane, and (meth)acryloyloxypropyltriethoxysilane, and 0 to 25% by mass of an arbitrary structural unit (3) derived from a vinyl monomer other than the monomer 1 and the monomer 2, and is a polymer having a number average molecular weight of 6,000 to 30,000. (In the general formula (1), R １ represents a hydrogen atom or a methyl group, A represents O or NH, X represents an ethylene group or a propylene group, Y represents O, NHCOO, or NHCONH, and R ２ each independently represents a hydrogen atom or a methyl group, n represents an average number of repeating units of 20 to 100, and R ３ represents an alkyl group having 1 to 18 carbon atoms)

2. The surface-treated inorganic oxide according to Claim 1, wherein the inorganic oxide is inorganic oxide fine particles having an average particle diameter of 10 nm to 100 μm.

3. The surface-treated inorganic oxide according to Claim 2, which is a treated product obtained by surface-treating 100 parts by mass of the inorganic oxide fine particles with 0.5 to 50 parts by mass of the polymer treating agent.

4. The surface-treated inorganic oxide according to Claim 2, wherein the inorganic oxide fine particles are at least one selected from the group consisting of titanium dioxide, zinc oxide, silica, alumina, and composite oxide pigments.

5. An article containing the surface-treated inorganic oxide according to any one of Claims 1 to 4.

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