Surface modifier and surface modification method

Abstract

To provide a surface modifier which polishes the surface of a workpiece while chemically modifying the surface, and a surface modification method using the surface modifier.SOLUTION: A surface modifier comprises abrasive grains and smectite, wherein the content of the abrasive grains is 50 to 98 pts.mass and the content of the smectite is 2 to 50 pts.mass, based on 100 pts.mass of the solids of the surface modifier.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a surface modifier and a surface modification method.

Background Art

[0002] Surface modification techniques are known for changing and modifying chemical and physical properties such as hydrophilicity, adhesiveness, corrosion resistance, durability, weather resistance, antifouling property, water resistance, and hydrophobicity of the material surface. In particular, when performing plating or painting on the material surface, unevenness of the plating solution or paint can be improved by hydrophilizing the material surface to improve the wettability of the surface. At this time, when dirt, oxides, etc. adhere to the material surface, or the surface unevenness is relatively large, the efficiency and effect of the surface modification treatment may decrease. Therefore, usually, before performing the above surface modification, the material surface is polished so that the surface is cleaned and smoothed. On the other hand, generally, an oxide film is likely to be formed on the surface of base metals, and even if the oxide film is removed by polishing, an oxide film may be formed again during the subsequent surface modification treatment. Therefore, for such materials, it is necessary to simultaneously perform polishing with an abrasive and surface modification with a surface modifier. Also, not limited to the materials as described above, by simultaneously performing polishing and surface modification, deterioration and recontamination of the material surface can be effectively prevented, and there is also an advantage of reducing the number of processes.

[0003] As an abrasive capable of coexisting an abrasive and a hydrophilizing agent which is a kind of surface modifier and achieving polishing and hydrophilization simultaneously, for example, Patent Document 1 discloses a semiconductor polishing composition containing abrasive grains and polyalkyleneimine, and characterized in that the surface of the polished object after polishing is hydrophilized. Patent Document 1 describes that the surface of a polished object such as a silicon wafer is hydrophilized by the action of the polyalkyleneimine. Also, Patent Document 2 discloses a polishing composition containing abrasive grains and a diallylamine-based polymer, and characterized in that the weight average molecular weight of the diallylamine-based polymer is 200 or more and less than 15,000. By containing the diallylamine-based polymer, aggregation of the abrasive grains can be suppressed, and the surface of the wafer after polishing can be hydrophilized without reducing the polishing rate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a polymer compound is used as a hydrophilizing agent for hydrophilizing the surface of a material, the polymer compound may cover the abrasive grains, resulting in a decrease in the polishing rate. Although the polishing composition described in Patent Document 2 addresses this problem, it is necessary to control the degree of polymerization of the diallylamine-based polymer, which is a hydrophilizing agent, to be low, and there are limitations on the materials that can be used. Also, even in the semiconductor polishing composition described in Patent Document 1, only polyethyleneimine with a molecular weight of 10,000 is demonstrated in the examples, and data on polyalkyleneimine on the higher molecular weight side is not disclosed, and the same problems as those of the invention described in Patent Document 2 are a concern.

[0006] An object of the present invention is to provide a surface modifier capable of chemically modifying the surface of an object to be treated while polishing the surface thereof, and a surface modification method using the surface modifier.

Means for Solving the Problems

[0007] In view of the above problems, the present inventor has conducted intensive studies. As a result, in the decantation process for purifying a high-purity smectite component from a smectite-containing ore, a sediment component containing silicon dioxide and smectite obtained as a by-product is recovered, and by using this to treat the surface of a metal plate, the surface of the metal plate can be polished, and at the same time, hydrophilization of the surface can be achieved. Furthermore, it has been found that smectite can effectively suppress the aggregation of silicon dioxide. The present invention has been completed based on these findings through further studies.

[0008] The above problems of the present invention have been solved by the following means. 〔1〕 A surface modifier containing abrasive grains and smectite, wherein in 100 parts by mass of the solid content of the surface modifier, the content of the abrasive grains is 50 to 98 parts by mass, and the content of the smectite is 2 to 50 parts by mass. 〔2〕 The surface modifier according to claim 1, wherein the surface modifier is a slurry containing 30 to 95% by mass of water. 〔3〕 The surface modifier according to claim 2, wherein the abrasive grains are abrasive grains selected from silicon dioxide, alumina, and calcium carbonate. 〔4〕 The surface modifier according to claim 3, wherein the surface modifier is a modifier for modifying the chemical properties of the surface of the object to be treated. 〔5〕 The surface modifier according to claim 4, wherein the surface modifier is a hydrophilizing agent for the surface of the object to be treated. 〔6〕 The surface modifier according to claim 5, wherein the object to be treated is an inorganic material. 〔7〕 The surface modifier according to claim 6, wherein the surface modifier is derived from a by-product fraction mainly composed of silicon dioxide generated in the process of subjecting the pulverized smectite-containing ore to decantation purification to obtain purified smectite. 〔8〕 The surface modifier according to claim 7, wherein the smectite is a smectite selected from montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and stevensite. 〔9〕 The surface modifier according to claim 8, wherein 50% of the particle diameter of the abrasive grains contained in the surface modifier is 0.1 to 100 μm. 〔10〕 A surface modification method for modifying the surface of the object to be treated using the surface modifier according to any one of claims 1 to 9.

Advantages of the Invention

[0009] The surface modifier of the present invention is excellent in abrasiveness and can further chemically modify the surface of the object to be treated. Further, the surface modification method of the present invention can polish the surface of the object to be treated and simultaneously chemically modify the surface thereof by using the above surface modifier.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0011] Hereinafter, preferred embodiments of the present invention will be specifically described, but the present invention is not limited to these embodiments except as defined in the present invention.

[0012] [Surface Modifier] The surface modifier of the present invention is a composition containing specific amounts of abrasive grains and smectite in its solid content. According to the surface modifier of the present invention, the surface of the object to be treated can be polished and smoothed by the abrasive grains, and at the same time, the smoothed surface can be modified by the smectite. Therefore, the polishing process and the surface modification process proceed simultaneously, so that the number of steps can be reduced, and the problem of deterioration of the object to be treated and adhesion of dirt between the two processes, which may occur when the two processes are performed separately, can be solved. Although the detailed mechanism by which the surface modifier of the present invention exerts the above-mentioned action and effect is not clear, it is presumed to be due to the following complex and intimate mechanism. In the surface modifier of the present invention, the contained abrasive grains function as an abrasive component. It is believed that the smectite acts directly (physically contacts) instantaneously on the surface of the object to be treated, where the surface is polished and smoothed by the abrasive grains, and further the oxide film and dirt on the surface are removed, thereby making it possible to modify the surface to the desired characteristics. Furthermore, smectite not only functions as a surface modifier, but also contributes to improving the dispersion stability of the abrasive grains and inhibits the aggregation of the abrasive grains, which is also believed to be one of the factors that improve the polishing characteristics.

[0013] The surface modifier of the present invention can modify the surface of the object to be treated as described above. The "modification" preferably includes modification of chemical properties. In the present invention and this specification, the "modification of chemical properties" does not include modification of physical properties such as smoothing by polishing with abrasive grains. The chemical properties are not particularly limited, and examples thereof include hydrophilicity, antifouling properties, adhesiveness, sliding properties, wear resistance, and corrosion resistance. Among these, the chemical properties are preferably hydrophilic. That is, the surface modifier of the present invention is preferably a hydrophilizing agent (hydrophilicity improving agent) for the surface of the object to be treated.

[0014] The form of the surface modifier of the present invention is not particularly limited, and it may be in any form, such as a lump (block), powder, paste, slurry, or liquid.

[0015] The components of the surface modifier of the present invention are described below.

[0016] (Abrasive grains) The surface modifier of the present invention contains abrasive grains as a polishing component. The abrasive grains can be determined in consideration of the hardness of the object to be treated, the desired smoothness, etc. In particular, substances with high hardness that can be used as abrasive grains include, for example, silicon dioxide such as quartz, amorphous silicon dioxide, aluminum oxides (alumina) such as alundum, white alundum, α-alumina, γ-alumina, cerium oxide, iron oxide, metal oxides other than aluminum such as tantalum oxide, niobium oxide, nitrides such as silicon nitride, boron nitride, carbides such as silicon carbide, carbonate compounds such as calcium carbonate, simple elements such as diamond, tungsten, etc. Among them, it is preferable that the abrasive grains are selected from silicon dioxide, alumina, and calcium carbonate. Further, the abrasive grains may be amorphous (non-crystalline) or may have a crystal structure. Also, they may be synthetic or natural products.

[0017] In particular, it is preferable that the abrasive grains are silicon dioxide. Silicon dioxide is abundant as a resource and is contained in large amounts in the smectite-containing ore described later, and can also be obtained in the purification process of clay minerals. Examples of silicon dioxide contained in large amounts in the smectite-containing ore include quartz, amorphous silicon dioxide, tridymite, cristobalite, coesite, stishovite, keatite, moganite, zyfferite, melanophlogite, opal, etc. Also, the silicon dioxide may be silicon dioxide derived from purified products or commercially available products. As an example of a commercially available product, for example, quartz powder (model number: SI008BP, 50% particle size: 4 μm, manufactured by High Purity Chemical Research Institute), amorphous silicon dioxide powder (model number: 37049-01, 50% particle size: 8 μm, manufactured by Kanto Chemical Co., Inc.), etc. can be mentioned.

[0018] The particle size of the abrasive grains can be appropriately set according to the purpose. From the viewpoints of preventing sedimentation when the surface modifier is used as a slurry or paste and polishing operability, it is preferable that the 50% particle size of the abrasive grains is larger than the 50% particle size of the smectite contained in the surface modifier of the present invention. The 50% particle size of the abrasive grains is preferably 0.1 to 100 μm, can be 0.5 to 50 μm, and can also be 2 to 30 μm. Further, it is preferable that no abrasive grains having a particle size of 100 μm or more (when simply referred to as "particle size", it means the particle size of individual particles) are contained, and it may be in a form not containing abrasive grains having a particle size of 50 μm or more, or may be in a form not containing abrasive grains having a particle size of 30 μm or more. In the present invention, the "50% particle size" of the abrasive grains is the median diameter (D50) based on volume. This particle size and particle size distribution can be determined by, for example, a laser diffraction / scattering type particle size distribution measuring device.

[0019] The peak in the particle size distribution of the abrasive grains may be one or may have a plurality of peaks. From the viewpoint of the uniformity of the polishing state, it is preferable that the peak in the particle size distribution is one. Further, the particle size distribution of the abrasive grains is preferably distributed within a certain narrow range. For example, when the surface modifier of the present invention is used for surface modification while performing mirror finishing, it is preferable that the 50% particle size of the abrasive grains is 0.1 μm or more and less than 15 μm. Further, when the surface modifier of the present invention is used for mirror finishing, in the particle size distribution of the abrasive grains, it is preferable that there is one or more (preferably one) peaks in the range where the particle size is less than 15 μm, and no coarse particles having a particle size of 15 μm or more are included. When there are a plurality of peaks in the particle size distribution and coarse particles having a particle size of 15 μm or more are included, it is preferable that there is one or more peaks in the range where the particle size is less than 15 μm, and no peak exists in the range where the particle size is 15 μm or more. Alternatively, when there are one or more peaks in the range where the particle size is less than 15 μm and one or more peaks in the range where the particle size is 15 μm or more, the maximum value of the peak frequency value (%) of the peak having a particle size of 15 μm or more (meaning the value (%) at the peak top) is preferably 1 / 5 or less of the maximum value of the peak frequency value (%) of the peak having a particle size of less than 15 μm.

[0020] (Smectite) The surface modifier of the present invention contains smectite as a surface modification component. Further, smectite also functions as a dispersion stabilizer for the abrasive grains, and can suppress the aggregation of the abrasive grains and improve the polishing characteristics.

[0021] The type of smectite constituting the surface modifier of the present invention is not particularly limited, and natural smectite or synthetic smectite can be appropriately used. Smectite itself is known and is also commercially available. When the surface modifier of the present invention is obtained through elutriation purification from a smectite-containing ore as described later, the smectite contained in the surface modifier is natural smectite derived from the smectite-containing ore. In the present invention or this specification, the "smectite-containing ore" means an ore containing smectite, and usually contains a certain amount of components other than smectite. For example, bentonite raw ore is a smectite-containing ore containing montmorillonite as smectite. The smectite is preferably one or more selected from montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and stibnite. When the smectite is natural smectite, it is preferably one or more selected from montmorillonite, beidellite, nontronite, hectorite, sauconite, and stibnite.

[0022] There is no particular limitation on the type of interlayer cation of the smectite used in the present invention. From the viewpoint of easy water swelling when used as an aqueous dispersion or an aqueous dispersion paste, it is preferably a monovalent metal ion, more preferably lithium ion and / or sodium ion. Also, from the viewpoint of improving the swelling property during water dispersion, the cation exchange capacity (CEC: Cation Exchange Capacity) of the smectite is preferably 20 meq (milliequivalent) / 100 g or more, more preferably 25 meq / 100 g or more, and even more preferably 30 meq / 100 g or more. Usually, the cation exchange capacity of the smectite used in the present invention is 250 meq / 100 g or less.

[0023] In the present invention, when referring to "smectite", it means particulate smectite. More specifically, the smectite preferably has a 50% particle size of 20 to 500 nm, more preferably 30 to 400 nm, even more preferably 40 to 380 nm, and particularly preferably 50 to 370 nm. By setting the 50% particle size of the smectite within the above preferred range, for example, when the surface modifier of the present invention is used as an aqueous dispersion, good thickening properties, dispersion stability of abrasive grains, adhesion to the workpiece to be polished, slipperiness during polishing, etc. can be imparted. In the present invention, the "50% particle size" of the smectite in the aqueous dispersion is the median diameter on a volume basis. This particle size can be determined, for example, by a laser diffraction / scattering type particle size distribution measuring device.

[0024] (Content of each component) In 100 parts by mass of the solid content (components other than the liquid medium) of the surface modifier of the present invention, the content of the abrasive grains is 50 to 98 parts by mass. From the viewpoint of improving the abrasiveness, the content of the abrasive grains in 100 parts by mass of the solid content is preferably 60 to 96 parts by mass, more preferably 70 to 93 parts by mass, and even more preferably 77 to 90 parts by mass. Also, in 100 parts by mass of the solid content of the surface modifier of the present invention, the content of smectite is 2 to 50 parts by mass. From the viewpoints of adhering to the surface after polishing to perform surface modification, improving the abrasiveness, preventing sedimentation and aggregation of abrasive grains when dispersed in water to improve the dispersion stability, and improving the slipperiness of the polishing liquid, etc., the content of the smectite is preferably 3 to 40 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 7 to 22 parts by mass.

[0025] (Content ratio of abrasive grains and smectite) In the surface modifier of the present invention, the content ratio of the abrasive grains to the smectite (content of abrasive grains: content of smectite) is not particularly limited, but from the viewpoints of dispersion stability of the abrasive grains, polishing characteristics, etc., it is preferably 20:1 to 1:1 on a mass basis, more preferably 12:1 to 2:1, and even more preferably 8:1 to 3:1.

[0026] (Water) The surface modifier of the present invention may be a dry product or may contain a liquid medium such as water. In particular, the smectite contained in the surface modifier of the present invention exfoliates and swells (exfoliates and disperses) in the coexistence of water, and the adhesiveness to the object to be treated is improved. Therefore, the surface modifier of the present invention is preferably in the form of a paste, slurry, or liquid containing water.

[0027] There is no particular limitation on the water, and it may be tap water or purified water such as distilled water or ion-exchanged water. Among them, from the viewpoints of rapidly exfoliating and swelling smectite and preventing viscosity increase and sedimentation, purified water from which ions in the water have been removed is particularly preferred. In this case, the ionic conductivity of the water is preferably 10 μS / m or less, more preferably 5 μS / m or less, and even more preferably 2 μS / m or less.

[0028] Further, when the surface modifier of the present invention contains water, the water content in the surface modifier is preferably 30 to 95% by mass. From the viewpoints of dispersion stability, workability, and adhesion to the object to be treated, the water content is more preferably 35 to 90% by mass, still more preferably 40 to 85% by mass, and still more preferably 45 to 80% by mass. Further, when the surface modifier of the present invention contains water, the abrasive grain content in the surface modifier is preferably 4 to 65% by mass, more preferably 9 to 60% by mass, still more preferably 13 to 55% by mass, and still more preferably 18 to 50% by mass. Further, when the surface modifier of the present invention contains water, the smectite content in the surface modifier is preferably 0.5 to 25% by mass, more preferably 1 to 20% by mass, still more preferably 1.5 to 15% by mass, and still more preferably 2 to 10% by mass.

[0029] (Other components) The surface modifier of the present invention may contain other components as long as the effects of the present invention are not impaired. For example, known and commonly used additives such as dispersants, surfactants, antifoaming agents, wetting agents, polymer materials, binders, and lubricants may be used. The surface modifier of the present invention is excellent in dispersion stability in water or the like by containing smectite. Therefore, it can be in a form without blending an organic dispersant or solvent. In this case, if the object to be treated is washed with water after treatment with the surface modifier, abrasive grains and the like, which are components of the surface modifier, can be easily removed from the object to be treated.

[0030] When the surface modifier of the present invention is produced using a by-product fraction obtained when a smectite ore is subjected to elutriation purification as described below, shale, mica, feldspar, calcite, pyrite, zeolite, kaolin, illite, etc. may be included as impurities. The surface modifier of the present invention may contain these impurities as long as the effects of the surface modifier of the present invention are not impaired. In this case, it is preferable that the content of the impurity component is 50 parts by mass or less with respect to 100 parts by mass of the content of the abrasive grains contained in the surface modifier of the present invention.

[0031] <Object to be treated> The object to be treated with the surface modifier of the present invention is not particularly limited. For example, metals such as stainless steel, iron, steel, copper, and aluminum, and inorganic materials such as glass, silicon, various ceramics, stone materials, and resin materials such as various plastics can be used as the object to be treated with the surface modifier of the present invention. Among them, from the viewpoint of the adhesiveness (adhesion) to the smectite contained in the surface modifier of the present invention, the object to be treated preferably contains metals such as simple metals and metal compounds (metal oxides, metal carbides, metal nitrides), and more preferably is a simple metal. The type of metal is not particularly limited as long as it is a metal that stably exists under normal conditions. Examples of such metals include magnesium, aluminum, titanium, chromium, manganese, iron, cobalt, copper, nickel, zinc, zirconia, molybdenum, tin, and lead.

[0032] [Manufacturing method of surface modifier] The surface modifier of the present invention can be obtained, for example, by mixing the above-described respective constituent components, and also, as described below, a by-product fraction (elutriation purification by-product fraction, sludge) generated in the process of subjecting a smectite ore to elutriation purification to obtain purified smectite can be recovered as the surface modifier of the present invention or its raw material to obtain the surface modifier of the present invention. Regarding the mixing method of the above-described respective constituent components, a known and commonly used material mixing method can be applied.

[0033] [Manufacturing method of surface modifier using elutriation purification by-product fraction] Hydraulic classification is a method of classifying solid particles by utilizing the difference in sedimentation rates of solid particles in water. The sedimentation rate at this time is described by Stokes' equation. In the present invention, the sedimentation of solid particles in hydraulic classification (hydraulic classification process) may be natural sedimentation or sedimentation by centrifugation or the like. When purifying smectite from a smectite-containing ore by hydraulic classification, a large amount of water is added to the smectite-containing ore and stirred, and the supernatant liquid component is recovered and dried, whereby smectite having a low specific gravity and being easily water-swellable can be purified. On the other hand, in this hydraulic classification purification process, a sedimentation component (by-product fraction) having a higher specific gravity than smectite is generated. This by-product fraction can be recovered and used as the surface modifier of the present invention or its raw material. The method itself of obtaining purified smectite from a smectite-containing ore by hydraulic classification is known. An example of the process of obtaining purified smectite and a by-product fraction from a smectite-containing ore by hydraulic classification is shown in FIG. 1 in its flow chart. The constituent components of the by-product fraction depend on the composition of the smectite-containing ore used as the raw material. From the viewpoint of the abundance ratio in the geology (Clark number) and the existence stability of the compound, silicon dioxide is generally the main component. In addition, compounds abundantly contained in the geology, such as alumina, calcium carbonate, and various iron oxides, can also be the main components or sub-components of the abrasive grains. Further, in the above-mentioned hydraulic classification purification, it is difficult to separate particles having a similar specific gravity or components that strongly interact (bond) with each other. Therefore, the obtained by-product fraction inevitably contains smectite at a certain ratio.

[0034] The by-product fraction may be recovered after performing hydraulic classification once. Further, it may be recovered after performing it a plurality of times. By performing hydraulic classification a plurality of times, the particle size and specific gravity of the obtained sedimentation components are made uniform. As a result, a fraction having a narrow particle size distribution and high purity can be obtained. Further, for the relatively high-specific-gravity fraction sedimented by natural sedimentation or gentle centrifugation, it can be removed, and then the by-product fraction sedimented under more severe centrifugation conditions can be used as the surface modifier of the present invention or its raw material. Such a by-product fraction has a relatively small particle size and a narrow particle size distribution. Each fraction of the above by-products can be used as the surface modifier of the present invention as it is. Further, the above by-product fraction can be subjected to desired treatments, such as drying treatment, classification treatment, centrifugation treatment, etc., to obtain the surface modifier of the present invention. In the present invention, the surface modifier being "derived from the by-product fraction" means including both of these forms.

[0035] When the surface modifier of the present invention is obtained from the by-product fraction by the above elutriation purification, the obtained surface modifier is excellent in abrasiveness, and further, when using the fraction components on the latter stage side, the congestion of coarse particles can be effectively suppressed. That is, for example, when using the by-product fraction of the first time of elutriation purification, since the particle size of the abrasive grains is large, the surface can be modified while performing rough polishing. Also, when using the by-product fraction after the second time of elutriation purification, since the particle size of the abrasive grains is small and more uniform, it can also be used for mirror polishing applications. Also, in elutriation purification, since the water dispersion treatment is performed for a long time, it is expected that the interaction between the abrasive grains centered on silicon dioxide, which is an abrasive component, and smectite will be strengthened. As a result of this interaction, the silicon dioxide, which is an abrasive grain, is in a state of being stably dispersed, and a surface modifier having more excellent abrasiveness, dispersion stability, slipperiness of the abrasive, etc. can be obtained.

[0036] Thus, in one embodiment, the present invention provides the following method for manufacturing a surface modifier.

[0037] A method for manufacturing a surface modifier, comprising recovering a by-product fraction mainly composed of silicon dioxide, which is generated in the process of subjecting pulverized smectite-containing ore to elutriation purification to obtain purified smectite, and using the by-product fraction to obtain a surface modifier having silicon dioxide in the by-product fraction as a polishing component.

[0038] According to the above manufacturing method, the by-product fraction that has conventionally been discarded can be effectively utilized as a surface modifier. Therefore, it contributes to the effective utilization of resources and enables an inexpensive and stable supply of a surface modifier exhibiting excellent abrasiveness and surface modification properties.

[0039] [Surface Modification Method] Still another embodiment of the present invention is a surface modification method using the surface modifier of the present invention. The surface modification method using the surface modifier of the present invention is not particularly limited, and for example, a known polishing treatment for polishing the surface of an object to be treated can be applied. Examples of such polishing treatments include abrasive cloth paper processing, grinding wheel polishing, lapping polishing, polishing, barrel polishing, wet blasting, and the like. When the surface modifier of the present invention is in a slurry form, treatment methods such as lapping polishing, polishing, barrel polishing, and wet blasting can be preferably used. When the surface modifier of the present invention is in a powder or paste form, treatment methods such as abrasive cloth paper processing and polishing can be preferably used.

Examples

[0040] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

[0041] (Example 1) The bentonite raw ore produced in Tsukiura, Yamagata Prefecture was crushed by a crushing roll, and 27 parts by mass of tap water was added to 3 parts by mass of the obtained coarsely crushed raw ore and allowed to stand for 24 hours to swell the bentonite raw ore. Then, after stirring for 30 minutes using a stirrer, it was allowed to stand for 2 hours, and then coarse precipitates were removed by decantation. The obtained supernatant was further separated by a centrifuge (conditions: 1000×g, 15 minutes), and the paste-like sediment component after removing the supernatant part was recovered to obtain the surface modifier of Example 1.

[0042] (Example 2) After the above centrifugation (conditions: 1000×g, 15 minutes), the paste-like sediment component was removed, and the obtained supernatant was further centrifuged (conditions: 8000×g, 15 minutes) to recover the paste-like sediment component. Otherwise, the surface modifier of Example 2 was obtained in the same manner as in Example 1 above.

[0043] (Example 3) A surface modifier of Example 3 was obtained in the same manner as in Example 2, except that bentonite raw ore produced in Mikawa, Niigata Prefecture was used instead of the bentonite raw ore produced in Tsukuba, Yamagata Prefecture.

[0044] (Example 4) To 10 parts by mass of the surface modifier of Example 2, 10 parts by mass of ion-exchanged water was added, and the mixture was stirred and mixed for 10 minutes in a stirring mode at 2000 rpm using a planetary mixer (Avatore Rentaro ARE-310, manufactured by Shinchi Co., Ltd.). The resulting viscous dispersion (diluted solution of the surface modifier of Example 2) was used as the surface modifier of Example 4.

[0045] (Example 5) To 20 parts by mass of aluminum oxide powder (product name: Micropolish (powder), abrasive particle size: 0.3 μm, manufactured by BUEHLER), 75 parts by mass of distilled water was added, and the mixture was stirred and mixed for 10 minutes in a stirring mode at 2000 rpm using a planetary mixer (Avatore Rentaro ARE-310, manufactured by Shinchi Co., Ltd.). To the resulting mixture, 5 parts by mass of purified montmorillonite (trade name: Kunipia F, average particle size: 300 nm, manufactured by Kunimine Industries Co., Ltd.) was added, and the mixture was further stirred and mixed for 10 minutes in a stirring mode at 2000 rpm using the above planetary mixer to obtain a paste-like material. This was used as the surface modifier of Example 5.

[0046] (Comparative Example 1) High-Home (manufactured by Nippon Kika Chemical Industry Co., Ltd.), a paste-like commercially available abrasive, was used as the surface modifier of Comparative Example 1.

[0047] (Comparative Example 2) Multi-purpose Cleanser (manufactured by Takeda Corporation), a paste-like commercially available abrasive, was used as the surface modifier of Comparative Example 2.

[0048] (Comparative Example 3) Picard Metal Polish (Nippon Abrasive Industry Co., Ltd.), a viscous liquid commercially available abrasive, was used as the surface modifier of Comparative Example 3.

[0049] (Comparative Example 4) To 5 parts by mass of refined montmorillonite (trade name: Kunipia F, average particle diameter: 300 nm, manufactured by Kunimine Industries Co., Ltd.), 95 parts by mass of distilled water was added and stirred with a stirrer for 1 hour. Then, using a planetary mixer (Avatotor Ryorotaro ARE-310, manufactured by Shinchi Co., Ltd.), it was stirred and mixed for 10 minutes in a stirring mode of 2000 rpm. The obtained viscous dispersion was used as the surface modifier in Comparative Example 4.

[0050] For each of the obtained surface modifiers of Examples 1 to 5 and Comparative Examples 1 to 4, the respective component compositions were analyzed, and further tests were conducted to determine the performance as surface modifiers. In the surface modifiers of Examples 1 to 5 above, in each case, the aggregation of abrasive grains was suppressed and the fine particle state was maintained.

[0051] [Analysis of Component Composition of Surface Modifiers in Examples] For the surface modifiers of Examples 1 to 3, the composition analysis was performed by the following method. The component composition of the surface modifier of Example 4 was calculated from the composition of Example 2 and the blending amount of water. Also, the component composition of the surface modifier of Example 5 was calculated from the blending amounts of the raw materials. The results are shown in Table 1.

[0052] (Water Content) The water content (mass %) in the surface modifier was measured by the drying loss method at 105 °C in accordance with Japanese Industrial Standard JIS A 1125:2015.

[0053] (Smectite Content) Utilizing the property that methylene blue is specifically adsorbed between the clay layers, the adsorption amounts of methylene blue were measured for the purified smectite powder and the dry powders of the surface modifiers of Examples 1 to 3, respectively, and the amount of smectite in the surface modifiers of Examples 1 to 3 was calculated as follows. The measurement of the methylene blue adsorption amount of smectite was carried out in accordance with the JBAS-107-77 method (filter paper method), which is a standard of the Japan Bentonite Industry Association. As reference products of smectite, high-purity (purity 99% by mass or more) purified smectite (product name: Kunipia F, derived from Tsukiho, Yamagata Prefecture or Mikawa, Niigata Prefecture, manufactured by Kunimine Industries Co., Ltd.) in which the quartz peak detected at around 27° in X-ray diffraction (XRD) measurement almost disappeared was used by repeating sedimentation purification for each of the bentonite raw ore from Tsukiho, Yamagata Prefecture and the bentonite raw ore from Mikawa, Niigata Prefecture. The methylene blue adsorption amount (unit: mmol / 100 g - purified smectite) of the purified smectite (powder dried at 105°C for 2 hours) used as the reference product was measured, and this measured value was used as the methylene blue adsorption amount (reference value) specific to montmorillonite in each bentonite raw ore. The methylene blue adsorption amount (reference value) of the purified smectite from Tsukiho, Yamagata Prefecture was 145 mmol / 100 g, and the methylene blue adsorption amount (reference value) of the purified smectite from Mikawa, Niigata Prefecture was 125 mmol / 100 g. The surface modifiers of Examples 1 to 3 were dried at 105°C for 2 hours and pulverized, and the methylene blue adsorption amount (unit: mmol / 100 g - purified smectite) was measured for each of the obtained dry powders. The measurement results of the methylene blue adsorption amount of the dry powders of the surface modifiers of Examples 1 and 2 using the bentonite raw ore from Tsukiho, Yamagata Prefecture were divided by the reference value of 145 mmol / 100 g, and the measurement results of the methylene blue adsorption amount of the dry powder of the surface modifier of Example 3 using the bentonite raw ore from Mikawa, Niigata Prefecture were divided by the reference value of 125 mmol / 100 g, and then each value was multiplied by 100. The obtained value was taken as the amount of smectite (amount of montmorillonite, unit: mass (%)) in the solid content of each surface modifier.

[0054] (Quartz content) Using a MiniFlex500 (manufactured by Rigaku Corporation), which is an X-ray diffraction (XRD) device, the X-ray reflection intensity was measured for the dry powders of the surface modifiers of Examples 1 to 3 above when the measurement range was 2θ = 1 to 65°, and X-ray diffraction data was obtained. The peak areas derived from quartz present around 2θ = 27° in the X-ray diffraction data of the dry powders of the surface modifiers of Examples 1 to 3 above were calculated. Further, as reference values, the peak areas derived from quartz present around 2θ = 27° in a 100% silicon dioxide standard product having the same particle size distribution as each of the above dry powders were calculated. The values obtained by multiplying by 100 the values obtained by dividing the peak areas obtained in Examples 1 to 3 by the peak areas obtained with each standard product were taken as the quartz contents (mass %) in the solid content of each surface modifier.

[0055] (Other components) The value obtained by subtracting the contents (g) of smectite and abrasive grains (quartz, alumina) from the solid content amount of the surface modifier (the amount obtained by subtracting the water content (g) from the total amount (g) of the surface modifier) was taken as the content of other components. From the above X-ray diffraction data, it was found that the dry powders of the surface modifiers of Examples 1 to 3 above slightly contained feldspar, calcite, etc. as the other components.

[0056] [Analysis of the component composition of the surface modifiers of the comparative examples] For the surface modifiers of Comparative Examples 1 to 3, composition analysis was performed by the following method. Further, the component composition of the surface modifier of Comparative Example 4 was calculated from the blending amounts of the raw materials. The results are shown in Table 1.

[0057] (Liquid content ratio) The liquid content ratio (mass %) in the surface modifier was measured by the 105 °C drying loss method in accordance with Japanese Industrial Standard JIS A 1125:2015. Based on the component compositions described in the catalogs of Comparative Examples 1 to 3, the measured liquid content ratios were the water content for Comparative Examples 1 and 2 and the organic solvent content for Comparative Example 3.

[0058] (Identification of abrasive grain components) The dry powder obtained in the above liquid content measurement was measured for the X-ray reflection intensity when the measurement range was 2θ = 1 to 65° using a MiniFlex500 (manufactured by Rigaku Corporation), an X-ray diffractometer (XRD), and X-ray diffraction data was acquired. Using a database from this data, the identification of the abrasive grains contained was performed. For any of the surface modifiers, only strong peaks derived from the abrasive grains (quartz in Comparative Examples 1 and 2, alumina in Comparative Example 3) were detected, and no peaks derived from the smectite component were detected. Note that the contents of quartz in Comparative Examples 1 and 2 and alumina in Comparative Example 3 described in Table 1 were the contents described in the catalog, respectively.

[0059] (Other components) The value obtained by subtracting the content (g) of the abrasive grains (quartz, alumina) described in the catalog from the solid content of the surface modifier (the amount obtained by subtracting the content (g) of water and organic solvent from the total amount (g) of the surface modifier) was taken as the content of other components.

[0060] [Performance determination test] For the surface modifiers of each example and comparative example, the following tests were conducted. The results are summarized in Table 1.

[0061] (Polishing test) As the objects to be treated, copper plates and iron plates (manufactured by Kennith) with a width of 20 mm and a length of 70 mm were used. Approximately 0.3 g of the surface modifiers of Examples 1 to 5 and Comparative Examples 1 to 4 were dropped onto the copper plates and iron plates, and using paper (Kimwipe, manufactured by Nippon Paper Crecia Co., Ltd.), they were polished manually by sliding them 20 times in the longitudinal direction while applying a constant force to the same area (treatment section). The surfaces of each metal plate after polishing were visually observed. When the copper plate and iron plate were polished to a mirror finish by the above polishing, it was judged as "〇", when the surface was almost mirror-finished but shallow scratches were also observed, it was judged as "△", and when it could not be polished (mirror-finished), it was judged as "×".

[0062] (Wetting tension test) The wettability tensions of the copper and iron plates after treatment with the surface modifiers of each example and comparative example were evaluated using a tension checker P type (manufactured by Pacific Chemical Co., Ltd.), which is a film wettability tension checking pen. The check pen is set to have a dyne number (mN / m) of 30 to 60 (in 2-step increments). For example, when using a check pen with a dyne number of 30 to 40, no breakage of the liquid film occurs after applying the ink to the metal plate. When using a check pen with a dyne number of 42 to 60 and breakage of the liquid film occurs after applying the ink, the wettability tension of the metal plate can be determined to be 40 mN / m. The higher the hydrophilicity of the plate surface, the higher the wettability tension. Ink was applied to the surfaces of the copper and iron plates after the above treatment using a check pen with a dyne number of 40, and the state of the liquid film 2 to 3 seconds later was visually observed. When the liquid film was applied without breakage or shrinkage and maintained the applied state, it was determined that it had at least the wettability tension (mN / m) of the dyne number. The application and observation were repeated using check pens with higher dyne numbers in the same manner. When breakage or overall shrinkage of the liquid film occurred within 2 to 3 seconds after applying the ink of the check pen with a dyne number of 40, the ink was sequentially applied using check pens with lower dyne numbers, and the application and observation were repeated in the same manner. By the above operation, the maximum dyne number of the check pen when no breakage of the liquid film occurred after applying the ink with the check pen was taken as the wettability tension (mN / m) of the copper and iron plates after the above treatment. Note that the wettability tensions of the copper and iron plates before treatment with the surface treatment agent were 34 mN / m and 36 mN / m, respectively.

[0063] (Wettability test) The wettability (surface hydrophilicity) of the copper and iron plates after treatment with the surface modifiers of each example and comparative example was evaluated as follows. A few drops of ion-exchanged water were dropped onto the surface of each metal plate using a dropper, and each metal plate was shaken so that the liquid droplets spread over the entire treated area of each metal plate (covered with water in a planar state). In this state, it was determined that "〇" when the liquid surface maintained the state of covering the entire surface of the treated area, and "×" when the liquid contracted into droplets. Note that when the above test was performed on any of the metal plates before treatment with the surface modifier, the dropped water became a droplet state (judgment: ×). In addition, Fig. 2 and Fig. 3 show the wetting states of the surfaces of the copper plates and iron plates after being treated with the surface modifiers of Example 1, Example 2, and Comparative Example 3, as well as the copper plates and iron plates before being treated with the surface modifiers.

[0064]

Table 1

[0065] As is clear from Table 1, when commercially available abrasives (Comparative Examples 1 to 3) containing abrasive grains and not containing smectite were used as the surface modifier, although the copper plates and iron plates could be polished, the wetting tension did not change before and after polishing, and it was also found that the wetting property of the surface was not improved. In addition, with the surface modifier of Comparative Example 4 containing only smectite without containing abrasive grains, the copper plates and iron plates could not be polished, and furthermore, subsequent surface modification could not be performed. In contrast, it was shown that the surface modifiers of Examples 1 to 5 containing both abrasive grains and smectite could polish the copper plates and iron plates, further improve the wetting tension after polishing, and also improve the wetting property of the surface.

Claims

1. A surface modifier containing abrasive grains and smectite, wherein the content of the abrasive grains is 50 to 98 parts by mass and the content of the smectite is 2 to 50 parts by mass in 100 parts by mass of the solid content of the surface modifier.

2. The surface modifier according to Claim 1, wherein the surface modifier is a slurry containing 30 to 95% by mass of water.

3. The surface modifier according to Claim 2, wherein the abrasive grains are abrasive grains selected from silicon dioxide, alumina, and calcium carbonate.

4. The surface modifier according to Claim 3, wherein the surface modifier is a modifier for modifying the chemical properties of the surface of the object to be treated.

5. The surface modifier according to Claim 4, wherein the surface modifier is a hydrophilizing agent for the surface of the object to be treated.

6. The surface modifier according to Claim 5, wherein the object to be treated is an inorganic material.

7. The surface modifier according to Claim 6, wherein the surface modifier is derived from a by-product fraction mainly composed of silicon dioxide generated in the process of subjecting the pulverized smectite-containing ore to elutriation purification to obtain purified smectite.

8. The surface modifier according to Claim 7, wherein the smectite is a smectite selected from montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and stibnite.

9. The surface modifier according to Claim 8, wherein 50% of the particle diameter of the abrasive grains contained in the surface modifier is 0.1 to 100 μm.

10. A surface modification method for modifying the surface of the object to be treated using the surface modifier according to any one of Claims 1 to 9.

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