JP5105470B2 - Suspension composition having suspension stability - Google Patents

Description

The present invention relates to a suspension composition in which inorganic fine particles are uniformly dispersed in water or an organic dispersion medium. Specifically, a dispersed phase composed of a metal oxide or the like can be dispersed in a dispersion medium composed of water or an organic solvent uniformly and stably for a long time without agglomeration, precipitation, or solidification. To a suspension composition which is

Industrially used suspension compositions containing inorganic fine particles (hereinafter referred to as “slurry”) mainly include fumed silica, alumina, iron oxide, titanium oxide, magnesium hydroxide, cerium oxide, silicon carbide, and boron carbide. The slurry used as a component is used for various purposes. These are used as pharmaceuticals or health functional foods called suspending agents, aqueous pigments, polishing slurries, coating liquids, hydraulic compositions, sprayed agricultural chemicals, and the like.

Specifically, the following slurry having inorganic fine particles as a dispersed phase can be exemplified. Suspensions or emulsions of pharmaceutical or health functional foods such as magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium silicate and aluminum hydroxide; fumed silica, cerium oxide, α-alumina, silicon carbide, boron carbide, trioxide Polishing slurry such as dimanganese and trimanganese tetraoxide; calcium carbonate, barium sulfate, cobalt oxide, bismuth vanadate, alumina, magnesium hydroxide, titanium oxide, cerium hydroxide, cerium oxide, zinc hydroxide, iron oxide, hydroxide Aqueous pigment ink, aqueous paint or coating liquid such as iron, magnesium oxide, magnesium hydroxide, magnesium carbonate, basic magnesium carbonate, silica and aluminum silicate; hydraulic composition such as clay, gypsum, cement, mortar, concrete; Carbonated Siumu, talc, clay, zeolite and agricultural emulsions, such as bentonite.

There are cases where the above-mentioned fine particles are suspended in water or an organic solvent to be slurried before use, and are commercially available in a slurry state. In any case, the fine particles are aggregated and precipitated in the slurry. Alternatively, it is required to have a property of being uniformly dispersed without solidifying, and capable of being redispersed by shaking or the like even if it is precipitated. Therefore, until now, attempts have been made to ensure dispersibility and long-term stability of dispersion by adding a pH adjuster, a dispersant, or a surfactant to the slurry composition.

For medicinal or health functional foods, active ingredients such as sparingly soluble aloe powder, turmeric powder, mint powder, royal jelly and other herbal medicines, kaolin, natural aluminum silicate, precipitated calcium carbonate, calcium lactate, calcium hydrogen phosphate, etc. Particles with specific effectiveness such as glaze and dry aluminum hydroxide gel, hydrotalcite, magnesium oxide, aluminum hydroxide, magnesium hydroxide, etc. or zinc compounds, calcium compounds, copper compounds, magnesium compounds, There is a so-called suspension or emulsion in which fine particles are pulverized or granulated and then suspended in purified water using a suspension stabilizer. In the suspension or emulsion, the suspension stabilizer that acts as a dispersant is usually called an emulsifier. Specific examples include cellulose ethers such as hydroxypropyl cellulose, synthesis of carboxyvinyl polymer and polyvinylpyrrolidone, and the like. Examples thereof include polymers, natural polymers such as alginic acid / hyaluronic acid and gum arabic, clays such as bentonite, and composites such as crystalline cellulose and carmellose sodium. In order to improve dispersibility, a surfactant may be further used. Examples of the surfactant include polysorbates, sorbitans, sodium lauryl sulfate, and the like. The suspension or emulsion thus prepared is used as an oral preparation, an external preparation for skin, an external preparation for nasal cavity, etc. depending on the purpose, but other components such as a buffer, an antiseptic and the like are used as necessary. Various fine particles as an agent, a preservative, a coloring agent, a corrigent / flavoring agent, an osmotic pressure regulator and the like are blended to obtain a final preparation.

In the suspension or emulsion, fine particles as active ingredients are uniformly dispersed in order to maintain a certain medicinal effect, and the sedimentation rate of the fine particles is required to be slow. Even if some of the particles are settling, they must be such that they can be easily redispersed by shaking before taking. Many conventional suspension stabilizers mainly form a gel and increase the viscosity to prevent free settling of the component particles. However, since the suspension or emulsion contains various kinds of fine particles as described above. During storage for a long period of time or due to a sudden change in the environment such as temperature, there is a problem that particles having a large particle diameter and particle density settle to form a cake and do not re-disperse.

In the field of abrasives, (1) in the manufacturing process of a semiconductor device, a slurry obtained by dispersing cerium oxide, silica or alumina as a dispersed phase (abrasive grain) in a low-viscosity dispersion medium such as water, It is used for polishing the surface of a semiconductor wafer by CMP and planarizing an inorganic insulating film layer. (2) In the processing of optical elements, a polishing slurry in which rare earth oxide abrasive grains containing cerium oxide are dispersed in an organic solvent such as water or alcohol as a dispersion medium is used for optical disks and magnetic disks by CMP. It is used for polishing glass substrates, LCD glass substrates, LSI glass substrates, photomask glass substrates, optical lenses, cathode ray tubes and the like. (3) In the surface finishing process in precision processing of metals, glass, ceramics, etc., abrasives are dispersed in high-viscosity dispersion media such as oils and fats and applied in pastes to substrates such as felts, buffs, and nonwoven fabrics. Often used. (4) In the polishing of medical and precision industrial parts (such as magnetic heads), a polishing tape or polishing sheet in which a thin resin substrate (tape or sheet) or non-woven fabric is coated with an abrasive composition dispersed in a resin binder Is used.

In the above abrasive, dispersibility and dispersion stability are extremely important, and poor dispersion causes various problems. Specifically, (1) in the manufacturing process of a semiconductor device, water or an organic solvent-based slurry in which an abrasive is dispersed is precipitated in a slurry storage tank of a polishing apparatus, or the particle size increases. Scratches (polishing scratches) are likely to occur, and in the optical field or surface finishing processes such as metal, glass, or ceramic, the slurry is circulated, so the agglomerated abrasive grains are precipitated and solidified on the polishing pad or substrate. However, “scratch” and “burnt” occur on the surface of the material to be polished due to the clogged pad. (2) In the surface finishing process in precision machining, if the dispersibility of the abrasive in the paste is poor, it is particularly good in mirror finish. (3) When polishing medical and precision industrial parts (magnetic heads, etc.), a polishing agent uniformly dispersed in an organic solvent is used to polish When kneading into a binder, it is dispersed in an organic solvent in advance and then added to the binder resin, but if the dispersion of the abrasive in the organic solvent is not uniform, the dispersibility of the abrasive in the binder is also poor and the object to be polished is There has been a problem that it cannot be polished into a smooth and desired shape, causing uneven wear and alteration.

Water-based pigment inks, water-based paints, or coating liquids are paints or coating liquids in which pigments and water-soluble resins such as water-based acrylic resins and amino resins are dispersed and dissolved in water-based solvents to improve pigment dispersibility. For this purpose, a dispersant called a fluidizing agent such as a sodium salt of isobutylene-maleic anhydride copolymer, a protective colloid resin or the like is used. However, since water has poor wettability to the pigment surface compared to solvents, water-based paints are poorer in dispersibility than conventional solvent-based paints and coating liquids even when the dispersant is added. In addition, water-based pigment inks that are also used as inks for OA inkjet printers are less expensive and have better light resistance and water resistance than dye inks, but are inferior in dispersibility, dispersion stability, and redispersibility. Attempts have been made to improve dispersibility by adding fine particles and adding a dispersant such as a surfactant and a pH adjuster. In recent years, ink dispersibility and dispersion stability have become more and more important in the trend toward higher drive frequencies and smaller droplets of inkjet print heads.

Dispersants of hydraulic compositions such as cement, mortar and concrete are called water reducing agents, and naphthalene sulfonate, melamine sulfonate, polystyrene sulfonate, polycarboxylate and the like have been used conventionally. However, the polycarboxylic acid cement dispersant also improves initial dispersibility, but is not satisfactory with respect to the temporal stability of the dispersion. Further, in the high water reduction rate region required for high-strength concrete. As a result, the fluidity of the concrete decreases, the viscosity increases particularly under high shear, and the pump load during pumping becomes extremely large, causing problems in pumping, causing the problem of reduced workability of the concrete composition. Yes. In particular, the viscosity of concrete increases, the workability decreases significantly in winter, and the initial dispersibility of the cement dispersant also decreases, increasing the required amount of addition and producing a long time for kneading. There is a problem that the performance decreases. Accordingly, there is a need for a cement dispersant that is excellent in high dispersibility, slump loss prevention, and viscosity reduction even in a high water reduction rate region.

Among so-called emulsions or wettable powders in which active ingredients of agricultural chemicals that are fine particles are uniformly dispersed in water with a dispersant, surfactant or emulsifier, among pesticides, formaldehyde condensates of lignin sulfonate, naphthalene sulfonate, etc. Although many anionic or nonionic surfactants have been used as emulsifiers, they are still insufficiently dispersed due to the influence of polyvalent cations such as calcium ions and magnesium ions contained as active ingredients. If stored at rest, it may settle and aggregate, resulting in poor redispersion and clogging of the spray nozzle. In addition, when a large amount of a thickener is added to prevent sedimentation, there is a drawback that it becomes impossible to spray due to an increase in viscosity.

As can be seen from the above description, precipitation / solidification prevention and redispersibility by natural sedimentation or coagulation sedimentation are common issues in any of the above fields. Accordingly, there is a demand for a dispersant that maintains good dispersibility of inorganic fine particles, which are active ingredients, and does not settle or solidify even when stored for a long period of time, and maintains redispersibility. Conventionally, such a dispersing agent is often an organic type, and has a drawback that it is difficult to treat waste slurry after use, has a large environmental load, and is expensive. Accordingly, the dispersant is preferably an inorganic dispersant with a low environmental load, and among them, one that does not contain harmful heavy metals is even more preferable.

In Patent Document 1, in an aqueous suspension pharmaceutical composition, the surface of a poorly water-soluble drug is coated with a negatively chargeable polymer such as carmellose sodium, and negatively charged crystalline cellulose / carmellose sodium particles are added. However, a method is disclosed in which repulsive force is generated between the two to keep the poorly water-soluble drug in a stable suspended state for a long period of time.

Patent Document 2 discloses an abrasive slurry with improved dispersibility and redispersibility for manufacturing a substrate such as a silicon substrate used in a semiconductor manufacturing process or an aluminum substrate used in an electrostatic chuck manufacturing process by CMP. Has been. According to this document, by adding a colloidal oxide such as colloidal silica or colloidal alumina having a particle diameter smaller than the abrasive particle diameter to a cerium oxide (CeO ₂ ) or silicon oxide (SiO ₂ ) -based polishing slurry, Settling and agglomeration of abrasive fine particles can be prevented without using any organic dispersant.

In Patent Document 3, a quinacridone pigment is dyed so as to be dissolved in water, and then fixed in an associated state in an inorganic layered compound such as hydrotalcite dissolved, swollen or dispersed in water. A method for obtaining a bright red quinacridone-based colorant having excellent dispersibility, water resistance and light resistance is disclosed.

Patent Document 4 discloses a gas phase process silica that is pulverized and has an average aggregated particle size after crushing of 0.001 times or more and 0.5 times or less with respect to the particle size of the powder coating material. Disclosed is a powder coating fluidizing agent obtained by subjecting phase titania and vapor phase alumina to surface hydrophobization treatment.

Patent Document 5 discloses a powdery cement dispersant composed of a liquid polycarboxylic acid copolymer and an inorganic powder. The liquid polycarboxylic acid copolymer and the inorganic powder are placed in a spray drying apparatus. A method for producing a powdered cement dispersant characterized by being introduced and spray-dried is disclosed. Inorganic powders in this document include finely pulverized products such as blast furnace slag and fly ash, and siliceous dust, silica fume, calcium carbonate, silica gel, and opal, which are by-products during production of silicon, silicon-containing alloys, zirconia, and the like. It is also possible to use clay minerals such as granite, titanium oxide, aluminum oxide, zirconium oxide, various glasses and bentonite, and calcined products thereof, fine powders such as amorphous aluminosilicate, chromium oxide and activated carbon.

Patent Document 6 discloses an aqueous suspension pesticide composition comprising a poorly water-soluble pesticide active ingredient having an average particle size of 1 μm or less, a dispersant, a surfactant, and water, and attapulgite, montmorillonite, etc. as a dispersant. An aqueous suspension pesticide composition is disclosed in which a sedimented layer formed in the lower part of the aqueous phase of the pesticide composition is easily redispersed by light shaking, using a clay mineral purified product dispersant of .

Patent Document 7 discloses a method of adding hydrotalcites as a dispersant in order to improve the dispersibility of titanium oxide pigments in resins, paints, and the like. However, this method improves the whiteness of the resin, but the dispersibility itself is not sufficiently improved.

Non-Patent Document 1 discusses the function of a surfactant in the dispersibility of a suspension in which an iron oxide pigment is dispersed in an aqueous ferric chloride solution as follows. In the ferric chloride aqueous solution, the iron oxide pigment surface is negatively charged, and iron ions in the solution are adsorbed around it to form an electric double layer. When sodium dodecyl sulfate (SDS), which is an anionic surfactant, is added to this suspension, in the state where SDS is further adsorbed, the SDS cancels out the positive charge adsorbed on the iron oxide pigment surface and aggregates. In the bilayer adsorption state, good dispersibility is exhibited.
Japanese Patent Laid-Open No. 11-130658 JP 2004-331852 A JP 2005-290071 A JP 2004-210875 A Japanese Patent No. 2666961 JP 2000-128704 A Japanese Patent No. 2838306 Issued by Technical Information Association, “Pigment Dispersion Technology-Surface Treatment and Use of Dispersing Agents and Dispersibility Evaluation”, First Printing February 24, 1999, p. 6-7

There are two types of sedimentation of the dispersed phase in the slurry: natural sedimentation where the dispersed phase particles settle due to gravity, and agglomeration sedimentation where the particles aggregate and settle because the electrostatic repulsion between the particles is small. Has been.

For the natural sedimentation, the conclusion derived from the Stokes equation, that is, from the rationale that the terminal sedimentation velocity is reduced by reducing the particle size and the weight density of the particles, and as a result, the sedimentation can be prevented. The method of making the fine particles into fine particles has been widely practiced and is a conventional technique. However, in various industrial fields, it is not always possible to make the dispersed phase particles fine, and in particular in the fields of abrasives and the like, there are many applications that must be particles of 0.5 μm or more due to the demand for polishing rate. The redispersion failure due to spontaneous sedimentation → sedimentation aggregation → solidification of fine particles of 0.5 μm or more which cannot be called ultrafine particles has not been solved.

Patent Document 6 discloses that natural sedimentation is prevented by adding a swellable compound typified by clay minerals such as bentonite and kaolinite to the dispersion medium as a dispersant to increase the viscosity and density of the dispersion medium. The method and, moreover, the method disclosed in Patent Document 3 in which the dispersed phase is supported on a carrier having good dispersibility is a known method having a great effect in preventing natural sedimentation. Some have the undesirable consequence of increased viscosity of the slurry. As is well known, in natural and synthetic clay minerals having a cation exchange capacity such as vermiculite and smectite, the basic layer portion has a permanent negative charge due to isomorphous substitution. It is not suitable for solving the problems in the invention.

As a method for preventing aggregation and sedimentation, (1) in the vicinity of the zero charge point, surface treatment is applied to the suspended particles according to the type of the dispersion medium to give charge and prevent aggregation. (2) A pH adjuster is added. The slurry is kept acidic or alkaline away from the zero point of charge (the absolute value of ζ-potential is large) and repelled by electrostatic repulsion (3) Addition of surface active agent to give surface charge and prevent aggregation These methods are proposed, and any of these methods is known. The method disclosed in Patent Document 4 is the above (1), the method disclosed in Patent Document 1 and Patent Document 2 is the above (2), the method disclosed in Patent Document 5 and Non-Patent Document 1 is the above ( It corresponds to 3). However, in the case of ordinary inorganic fine particles, the absolute value of the ζ-potential is rarely increased on both the positive side and the negative side from the zero charge point, and it is far from the zero charge point on either the positive side or the negative side. Even in the pH region, since the absolute value of the ζ-potential is as small as about 10 mV, it is often in a state where it tends to coagulate and settle. Therefore, in any of the above methods (1) to (3), it is necessary to adjust the pH of the slurry to the side where the absolute value of the ζ-potential is always increased, and there is a problem that the use is greatly restricted.

For example, in the case of a slurry of titanium oxide, alumina, cerium oxide or the like having a charge zero point of 6 to 8, in the high pH region where the pH is 10 or more, the ζ potential of the particles is about −10 mV and the absolute value is small. Conventionally, a pH adjusting agent was added to adjust the pH from weakly acidic to acidic at which the ζ potential becomes about +40 mV, thereby improving dispersibility. Therefore, a stable suspension such as alumina usually has to be weakly acidic to acidic, and cannot be used depending on applications.

Alternatively, in the case of a slurry such as silica having a charge zero point of 2 to 3, negative charge is dominant on the particle surface in a wide range of weak acidity to alkalinity, but since the ζ potential is as small as −10 mV, conventionally, A pH adjusting agent was added to adjust the pH to an acid value where the ζ potential was about +40 mV to improve dispersibility. That is, a stable slurry of silica must be acidic and could not be used depending on the application.

In addition, the dispersion stabilization method only by adjusting the pH as described above has a problem that depending on the surrounding environment such as the temperature, the dispersibility is deteriorated with time and aggregation and sedimentation occur.

Therefore, recently, in order to improve the dispersibility in a wide range regardless of whether the slurry is acidic or alkaline, an anionic surfactant and a nonionic surfactant are used in combination at a pH lower than the zero charge point. On the other hand, in the region where the pH is higher than the zero charge point, a method of preventing coagulation sedimentation by using a cationic surfactant and a nonionic surfactant in combination is often used. The slurry contains various types and a large amount of surfactants, and there is a problem that a large restriction is imposed on the application due to foaming or the like. In addition, depending on the application, salts contained in the surfactant may have an undesirable effect, and using a large amount of expensive surfactant leads to an increase in cost.

It is an object of the present invention to perform aggregation sedimentation and natural sedimentation in a slurry obtained by dispersing inorganic fine particles as a dispersed phase in water or an organic dispersion medium without imparting undesirable properties such as viscosity increase, foaming, and cost increase of the slurry. The present invention provides a method for preventing the dispersion and improving the uniform dispersibility of inorganic fine particles, the long-term stability of the uniformly dispersed state, and the redispersibility.

As a result of intensive studies to obtain a better method that satisfies this object, the present inventors are represented by the following chemical formula 1, and the average particle size is 1/100 to the average particle size of the suspended particles. It has been found that a hydrotalcite compound that is 1/2 is particularly suitable as a dispersant for an aqueous slurry.

(In the chemical ^formula 1, M ₁ ²⁺ is at least one divalent cation selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Ni ²⁺ and Cu ²⁺ , and M ³⁺ is at least one selected from the group consisting of Al ³⁺ and Fe ^3+. seed trivalent ^{cation, a n-is _{CO 3 2-, SO 4 2-,}} SO 3 2-, PO 4 3-, HPO 3 2-, CO 3 2-, NO 3 -, SiO 4 4-, (At least one n-valent anion selected from the group consisting of SiO ₃ ^2- and BO ₃ ^3- , m and x are 0 ≦ m ≦ 1, 0.2 ≦ x ≦ 0.5.)

  That is, the inventors have improved the dispersibility of the slurry by adding the hydrotalcite compound to the slurry in which alumina or silica is suspended in water, and the sedimentation over time due to natural sedimentation. We obtained knowledge from experimental results that aggregation and solidification can be prevented. Furthermore, by adding an appropriately selected surfactant together with the above hydrotalcite compound, it is not necessary to use other surfactants and dispersants in combination or to add a pH adjuster, etc., and it is influenced by the surrounding environment. The present inventors have found that the dispersibility of the slurry can be maintained over a long period of time, and have completed the present invention.

As is well known, a clay mineral containing a hydrotalcite compound has both a permanent charge and a mutation charge as a charge. In particular, in the case of a hydrotalcite compound, a part of M ₁ ^{2+ in} Chemical ^Formula ₁ Due to isomorphous substitution with M ³⁺ , the crystal surface is one of the few clay minerals that is always positively charged. In order to neutralize this charge, anions such as CO ₃ ²⁻ and SO ₄ ²⁻ are incorporated between the layers to form a mutated charge. Considered to be dominant. Since the permanent positive charge is not affected by the surrounding environment, the pH of the suspension in which the hydrotalcite compound is dispersed in water is higher than the pH (7 to 10) of the charge zero point of the variant charge of the hydrotalcite compound. Whether large or small, the crystal surface is always positively charged. Therefore, due to the repulsion between the permanent positive charges described above, the hydrotalcite compound itself is extremely dispersible regardless of whether it is in a polar or nonpolar solvent.

Examples of substances having such characteristics, that is, the permanent positive charge is dominant on the entire crystal surface, include Li-Al hydrotalcite compounds represented by the following chemical formula 2 and synthetic charcos represented by the chemical formula 3. An anodized compound is mentioned.


(G ²⁺ represents at least one divalent metal ion of Mg, Zn, Ca, and Ni. A represents at least one anion of silicon-based, phosphorus-based, and boron-based oxygenate ions, and a part thereof. And / or all indicate at least one anion of silicon-based, phosphorus-based and boron-based multimer oxygenate ions, B indicates at least one anion other than A, y ₁ , y ₂ , X, z ₁ , z ₂ and b each satisfy the following conditions: y ₁ and y ₂ are 0 <y ₁ ≦ 1, 0 ≦ y ₂ < _1, 0.5 ≦ (y ₁ + y ₂ ) ≦ 1, X is X = y ₁ + 2y ₂ , z ₁ and z ₂ are 0 <z ₁ , 0 <z ₂ , b is 0 ≦ b <5)


(Q ₁ ²⁺ represents Zn ²⁺ or Cu ²⁺ , Q ₂ ²⁺ represents at least one divalent metal ion of Ni ²⁺ , Co ²⁺ , Zn ²⁺ , Cu ^2+, and Mg ²⁺ , and a is 0.3 <a <2.0, ζ represents 0 ≦ ζ <1.0, b represents 10 <b <14, and ^Ar− represents SO ₄ ²⁻ , HPO ₄ ²⁻ , CO ₃ ²⁻ , SO ₃ ^2−. , HPO ₃ ²⁻ , NO ₃ ⁻ , H ₂ PO ₄ ⁻ , Cl ⁻ , OH ⁻ and silicate ions are selected, c is 0.4 <c <2.0, and q is (Shows a number from 0 to 4)

In the present invention, the hydrotalcite compound is referred to as the hydrotalcite compound represented by Chemical Formula 1 and the Li-Al hydrotalcite compound represented by Chemical Formula 2 together. "Compound" or simply "hydrotalcite". In the present invention, the synthetic charcoalmite compound means a compound represented by Chemical Formula 3, and is hereinafter referred to as “synthetic charcoalmite compound” or simply “charcoalmite”.

In the alumina slurry having a pH range higher than the zero charge point, the surface of the alumina particles is negatively charged. However, since the absolute value of the ζ-potential is as small as 10 mV, it easily aggregates and settles. The absolute value of the potential may be even smaller. Since the hydrotalcite surface has a positive permanent charge as described above, an anion is added to the hydrotalcite surface by adding hydrotalcite to the alumina slurry together with an anionic polymer surfactant such as polycarboxylate. The high molecular weight surfactant is adsorbed to give a negative charge. Therefore, electrostatic repulsion acts between the negatively charged alumina particles and hydrotalcite particles, and the dispersibility of the slurry is maintained.

  On the other hand, in the alumina slurry having a pH range lower than the zero charge point, the negatively charged hydrotalcite particles are similarly applied to the surface of the positively charged alumina particles because the polycarboxylate is adsorbed to give negative charges. During this time, electrostatic repulsion acts and the dispersibility of the slurry is maintained. As shown in the following examples, both alumina particles and hydrotalcite particles that are positively charged without adding a surfactant such as polycarboxylate in a pH region lower than the zero charge point of the alumina particles. During this period, electrostatic repulsion acts and the dispersibility of the slurry is maintained.

  However, in the above alumina slurry, alumina particles having a particle diameter of 1 μm or more rapidly spontaneously settle and agglomerate and solidify in a low viscosity solvent. Originally, the presence of electrostatic repulsion between particles alone cannot prevent spontaneous sedimentation of particles. Therefore, for such natural sedimentation, the above pH adjustment and addition of a surfactant are effective solution means. However, in conventional slurries, even when a pH adjuster or a surfactant was added, the aggregation and solidification due to natural sedimentation was not improved. However, in the slurry according to the present invention, hydrotalcite particles and the like prevent natural sedimentation of suspended particles. Although the mechanism is unknown, the present inventor has found that hydrotalcite particles tend to disperse uniformly regardless of the pH value of the slurry, due to the electrostatic charge of the permanent positive charge on the surface. Hydrotalcite particles that are negatively charged by adsorbing carboxylate and the like are uniformly distributed among suspended particles due to mutual electrostatic repulsion, and the average particle size of hydrotalcite particles, etc. It is considered that the reason is that it is 1/2 or less of alumina particles and does not contain coarse particles.

  The suspension composition in the present invention is characterized by containing a hydrotalcite compound or the like, thereby maintaining its dispersibility, long-term stability of dispersion, and redispersibility. The suspension composition may contain a surfactant or the like as necessary.

Further, as described above, the hydrotal of the chemical formula 1 can also be obtained by using a Li-Al hydrotalcite compound and a synthetic charcoalmite compound represented by chemical formulas 2 and 3 having permanent positive charges on the surface. It is clear that the same effect as the site compound can be obtained. These can be synthesized according to known methods described in JP-A-2001-2408 and JP-A-3762571, respectively.

Thus, according to the present invention, the following suspension stabilizer composition and use thereof are provided.
(1)
In a liquid dispersion medium in which inorganic fine particles (component a) are dispersed, at least one inorganic hydroxide particle selected from the group consisting of hydrotalcite compounds and synthetic charcoalmite, and an average particle diameter larger than that of the inorganic fine particles A suspension composition having a suspension stability obtained by blending small particles (component b).
(2)
The suspension composition having suspension stability according to claim 1, further comprising a surfactant.
(3) The suspension composition as described in (1) or (2) above, wherein the liquid dispersion medium is water, an organic dispersion medium, or a mixture thereof.
(4) The suspension composition as described in (3) above, wherein the organic dispersion medium is at least one selected from ethanol, ethylene glycol or glycerin.
(5) The inorganic fine particles are magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium silicate, aluminum hydroxide, fumed silica, cerium oxide, α-alumina, silicon carbide, boron carbide, dimanganese trioxide, and four-three. Manganese oxide, calcium carbonate, barium sulfate, cobalt oxide, bismuth vanadate, titanium oxide, cerium hydroxide, zinc hydroxide, iron oxide, iron hydroxide, cupric hydroxide, basic copper sulfate, basic magnesium carbonate, The suspension composition as described in (1) or (2) above, which is at least one selected from aluminum silicate, clay, gypsum, cement, mortar, concrete, talc, clay, zeolite and bentonite .
(6) The inorganic fine particles are at least one selected from aluminum hydroxide, fumed silica, cerium oxide, α-alumina, calcium carbonate, cupric hydroxide, basic copper sulfate, mortar and bentonite. The suspension composition as described in (1) or (2) above,
(7) The suspension composition as described in (2) above, wherein the surfactant is at least one anionic polymer surfactant selected from anionic polymer surfactants.
(8) The above anionic polymer surfactant is at least one anionic polymer surfactant selected from carboxylates, sulfates, sulfonates and phosphates The suspension composition according to (7).
(9) The anionic polymer surfactant is at least one selected from polycarboxylic acid-based, naphthalene-based, melamine-based, and aminosulfonic acid-based surfactants. Suspension composition.
(10) The suspension composition as described in (7) above, wherein the anionic polymer surfactant is at least one kind belonging to a polycarboxylic acid multi-element polymer or a polycarboxylic acid ether.
(11) The blending amount of component b (= the blending amount of component b / the blending amount of component a) with respect to the blending amount of inorganic fine particles (component a) is in the range of 0.1 to 1.0 by weight ratio. The suspension composition as described in (1) or (2) above,

Hereinafter, the suspension composition of the present invention will be described in more detail.

The average particle size of the hydrotalcite compound, Li-Al hydrotalcite compound and synthetic charcoalmite compound used in the present invention is 1/100 to 1/2 of the average particle size of the inorganic fine particles which are the dispersed phase. Size is preferred. More preferably, it is 1/10 to 1/2 of the average particle diameter of the inorganic fine particles, and further preferably 1/4 to 1/2. When the ratio is larger than 1/2, the natural sedimentation preventing effect is not sufficient, and when it is less than 1/100, the aggregation sedimentation preventing effect is decreased, and the viscosity of the slurry may be excessively increased. Specifically, when the average particle size exceeds 5 μm, natural sedimentation is likely to occur, and when it is less than 0.1 μm, the effect of preventing aggregation and sedimentation decreases, and the viscosity of the slurry may excessively increase. It is preferable to use hydrotalcite compound particles having an average particle diameter of 0.1 to 5 μm, and more preferable to use hydrotalcite compound particles having an average particle diameter of 0.1 to 1 μm. preferable. As the hydrotalcite compound having such a particle size, it is preferable to use a hydrotalcite compound that is highly dispersible and fine particles synthesized according to a method described in, for example, Japanese Patent Publication No. 58-46146. . Specifically, for example, a white precipitate formed by continuously contacting a mixed solution of magnesium chloride and aluminum sulfate with sodium carbonate or a mixed aqueous solution of sodium carbonate and caustic soda at a constant flow rate is filtered and washed. Thereafter, a hydrotalcite compound synthesized by a known method of hydrothermal treatment at 150 to 250 ° C. is used. Hydrotalcite compounds or natural hydrotalcite compounds that have not been hydrothermally treated can only be obtained by pulverizing and classifying them so that the particle diameter exceeds 5 μm, which is not suitable for solving the problems in the present invention. is there.

Moreover, it is preferable to use what was synthesize | combined according to the method described in Unexamined-Japanese-Patent No. 2001-2408 as a Li-Al hydrotalcite type compound whose average particle diameter is 0.1-1 micrometer. Specifically, for example, it is synthesized by the following method. : A mixed solution of a lithium sulfate solution and an aluminum sulfate solution is placed in a stainless steel container, and while stirring, a slurry obtained by adding a sodium hydroxide solution and reacting is further subjected to hydrothermal treatment at 170 ° C. After cooling, filtering and washing with water, the dehydrated product is slurried again, and a sodium silicate solution is added and stirred at 90 ° C. The Li-Al hydrotalcite-based compound that has not been subjected to the hydrothermal treatment can only be obtained when the particle diameter exceeds 5 μm even after pulverization and classification, and is unsuitable for solving the problems in the present invention.

Similarly, it is preferable to use what was synthesize | combined according to the method described in the patent 3762571 as the synthetic charcoalumite compound whose average particle diameter is 0.1-1 micrometer. Specifically, for example, it is synthesized by the following method. : While stirring a mixed solution of copper sulfate, zinc sulfate and aluminum sulfate at room temperature, a sodium hydroxide solution was poured into this and the resulting coprecipitate was filtered, washed with water, zinc sulfate and sulfuric acid. Suspend in a mixed solution with copper. The suspension is hydrothermally reacted at 140 ° C., filtered and washed with water. The synthetic charcoalmite compound that has not been subjected to the hydrothermal treatment can only be obtained when the particle diameter exceeds 5 μm even after pulverization and classification, and is unsuitable for solving the problems in the present invention.

In Formula 1, M ₁ ²⁺ is at least one divalent cation selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Ni ²⁺ and Cu ²⁺ , and M ³⁺ is at least one selected from the group consisting of Al ³⁺ and Fe ^3+. trivalent ^{cations, a n-is _{CO 3 2-, SO 4 2-,}} SO 3 2-, PO 4 3-, HPO 3 2-, CO 3 2-, NO 3 -, SiO 4 4-, SiO ₃ ^2- and BO ₃ ^3- are at least one n-valent anion selected from the group consisting of any one of M ₁ other than those listed above as long as the permanent positive charge of the hydrotalcite compound is maintained. ^{2+, M 3+} and ^{a n-} is not intended to reduce the effects of the present invention is obvious.

Similarly, for the Li-Al hydrotalcite compound and the synthetic charcoalmite compound represented by chemical formulas 2 and 3 having permanent positive charges on the surface, as long as the structure maintains the permanent positive charge, Even if G ²⁺ , A and B in Chemical ^Formula ₂ or Q ₁ ²⁺ , Q ₂ ²⁺ and ^{Ar −} in Chemical ^{Formula 3} are arbitrary elements other than those described above, the effect thereof is not reduced.

On the other hand, a clay mineral in which the base layer portion is permanently negatively charged by isomorphous substitution, such as well-known vermiculite and smectite, has a particle diameter of 0.1 to 1 μm, and the clay mineral particles have a particle size of 0.1 to 1 μm. If the slurry has excellent dispersibility, a cationic polymer surfactant is used in combination when the pH of the slurry is in a region where the pH is lower than the charge zero point, while the surfactant is used in a region where the pH is higher than the charge zero point. However, since commercially available cationic polymer surfactants are few and expensive, they are not suitable for solving the problems in the present application.

In the present invention, inorganic fine particles as a dispersed phase dispersed in water or an organic dispersion medium are magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium silicate, aluminum hydroxide, fumed silica, cerium oxide, α-alumina, carbonized. Silicon, boron carbide, dimanganese trioxide, trimanganese tetraoxide, calcium carbonate, barium sulfate, cobalt oxide, bismuth vanadate, titanium oxide, cerium hydroxide, zinc hydroxide, iron oxide, iron hydroxide, basic magnesium carbonate , Aluminum silicate, clay, gypsum, cement, mortar, concrete, talc, clay, zeolite, bentonite, and the like, the suspension stabilizer composition of the present invention is particularly aluminum hydroxide, among the above inorganic fine particles, Fumed silica, cerium oxide, α- Suitable for alumina, calcium carbonate, cupric hydroxide, basic copper sulfate, mortar, bentonite and the like.

The surfactant used in the present invention may be an anionic polymer surfactant, and preferably at least one anionic high surfactant selected from carboxylates, sulfates, sulfonates and phosphates. Molecular surfactant, more preferably at least one selected from polycarboxylic acid-based, naphthalene-based, melamine-based and aminosulfonic acid-based surfactants, more preferably polycarboxylic acid ammonium salt, allyl ether copolymer, polycarboxylic acid multicomponent Polymer, polycarboxylic acid ether, polyoxyethylene alkyl ether carboxylate, acylated peptide, sodium benzenesulfonate, alkylbenzenesulfonate, alkylnaphthalenesulfonate, formalin polycondensate of melaminesulfonate, dialkyls Succinic acid ester salt, sulfosuccinic acid alkyl di-salt, polyoxyethylene alkyl sulfosuccinic acid di-salt, α-olefin sulfonate, alkyl ether sulfate, polyoxylene ethylene alkyl ether phosphate, polyoxyethylene alkyl allyl ether phosphate , Allyl alcohol, maleic anhydride and styrene copolymer and at least one of the graft compounds of polyoxyalkylene monoalkyl ether, particularly preferably allyl alcohol, maleic anhydride and styrene copolymer, and polyoxyalkylene A graft compound dispersant having a graft side chain such as a graft compound with a monoalkyl ether is used, and a graft side chain having a molecular weight of 1500 or less, preferably 1000 or less is used. Preferably, the component of the polyoxyalkylene monoalkyl ether in the graft side chain is mainly composed of ethylene oxide. Particularly preferably, the component of the polyoxyalkylene monoalkyl ether in the graft side chain contains ethylene oxide as a main component and contains 50 mol% or less of propylene oxide.

In the suspension composition of the present invention, the blending amount of hydrotalcite or charcoalmite with respect to the blending amount of the inorganic fine particles as the dispersed phase is preferably in the range of 0.1 to 1.0 by weight ratio. A more preferred range is 0.1 to 0.5, most preferably 0.1 to 0.35. When the ratio is less than 0.1, hydrotalcite or the like does not exhibit an effect as a dispersant, and when it exceeds 1.0, the viscosity of the slurry may be excessively increased.

In the suspension composition of the present invention, the amount of the surfactant added as necessary is in the range of 0.01 to 1.0 by weight with respect to the amount of the inorganic fine particles as the dispersed phase. It is preferable. If it is less than 0.01, the effect does not appear, and if it exceeds 1.0, foaming tends to occur. In addition, the surfactants listed above are generally expensive as additives, and the use of the surfactant in a ratio exceeding 1.0 leads to an increase in cost. In the present invention, it is also a great advantage that it is not necessary to add a surfactant in an acidic region, particularly in a pH region lower than the charge zero point of inorganic fine particles.
In the present invention, it is preferable that the dispersion medium is appropriately pH-adjusted according to the type of the dispersed phase, particularly the pH value at the zero charge point of the mutated charge of the dispersed phase. The pH adjuster is not particularly limited other than those imposed by the application, inorganic salts such as monovalent or divalent metal hydroxides and carbonates, alkaline substances such as ammonia and organic amines, or hydrochloric acid It can be carried out using acidic substances such as phosphoric acid, sulfuric acid, nitric acid and various organic acids.

In the present invention, since the permanent charge on the surface of hydrotalcite or charcoalumite is not affected by the polarity of the dispersion medium, the suspension composition of the present invention has either the water or the organic dispersion medium. However, suitable organic dispersion media include ethanol, ethylene glycol, or glycerin.

The effect of the present invention is that a suspension composition obtained by dispersing inorganic fine particles in water or an organic dispersion medium does not impart undesirable properties such as an increase in viscosity, foaming, and cost increase of the suspension composition. In addition, it is possible to provide a composition having improved uniform dispersion of inorganic fine particles, long-term stability in a uniform dispersion state, and redispersibility.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all chemicals used below were first grade reagents manufactured by Wako Pure Chemicals except those specifically described. All procedures from preparation of the suspension to evaluation were carried out at 24 to 25 ° C. except those specifically described. The measurement result about a sedimentation rate and redispersibility is shown to Tables 1-3.

(Dispersibility of polishing slurry)
At room temperature, water 200 mL, aluminum oxide powder (average particle size 2.42 μm) 2 g, anionic surfactant 1 (sodium dodecylbenzenesulfonate) 0.5 g, synthetic hydrotalcite compound particles (average particle size 0.5 μm) Product name: DHT-6 / Kyowa Chemical Industry Co., Ltd.) 0.5 g and 0.1 mol / L sodium hydroxide 16 ml are mixed in a 250 mL settling tube and immediately subjected to ultrasonic dispersion treatment for 3 minutes for dispersion. A polishing slurry was prepared. The slurry had a pH of 11.71.
Moreover, when the viscosity of this slurry was measured, it was 1.8 cP (27.5 degreeC). Even though the viscosity of ion-exchanged water measured by the same method was 1.8 cP, no increase in viscosity was observed.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of cationic surfactant (octadecyltrimethylammonium chloride, trade name: Cationic AB / Nippon Yushi Co., Ltd.), synthesis used in Example 1 Hydrotalcite compound particles (0.5 g) and 0.1 mol / L hydrochloric acid (16 ml) were mixed in a 250 mL settling tube, and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The pH of this slurry was 3.98.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL water, 2 g aluminum oxide powder used in Example 1, 0.5 g anionic surfactant 1 (sodium dodecylbenzenesulfonate), 0.5 g synthetic hydrotalcite compound particles used in Example 1 Then, 16 ml of 0.1 mol / L hydrochloric acid was mixed in a 250 mL settling tube, and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The pH of this slurry was 4.30.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of nonionic surfactant (polysorbate 80, trade name: Tween 80 / Merck Japan), synthetic hydrotalcite compound particles used in Example 1 0.5 g and 16 mol of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 3.71.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the synthetic hydrotalcite compound particles used in Example 1 and 16 ml of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube. Immediately after that, an ultrasonic dispersion treatment was performed for 3 minutes to disperse to prepare a polishing slurry. The pH of this slurry was 3.90.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, an anionic surfactant 2 (a graft compound of an allyl alcohol, maleic anhydride and styrene copolymer and a polyoxyalkylene monoalkyl ether, The molecular weight of the graft side chain is 500, and the polyoxyalkylene monoalkyl ether component in the graft side chain is 100% ethylene oxide. (Marialim AKM0531 / Nippon Yushi) 0.5 g, Example 4 of Japanese Patent No. 3762571 Synthetic charcoalmite compound particles with an average particle size of 0.8 μm synthesized by the method described (but without surface treatment)

0.5 g and 16 mol of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 3.06.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of anionic surfactant 2, and the method described in Example 13 of JP-A No. 2001-2408 (but the surface treatment was performed) Li-Al hydrotalcite compound with an average particle size of 1.0 μm synthesized according to

0.5 g and 16 ml of 0.1 mol / L sodium hydroxide were mixed in a 250 mL settling tube and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 11.74.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of ethylene glycol, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the anionic surfactant 1, 0.25 g of synthetic hydrotalcite compound particles used in Example 1, and 0.1 mol / 16 ml of L sodium hydroxide was mixed in a 250 mL settling tube, and immediately subjected to ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The pH of this slurry was 11.25.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of ethylene glycol, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the synthetic hydrotalcite compound particles used in Example 1 and 16 ml of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube. Immediately after that, an ultrasonic dispersion treatment was performed for 3 minutes to disperse, thereby preparing a polishing slurry. The slurry had a pH of 3.44.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of methanol, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the anionic surfactant 1, 0.5 g of synthetic hydrotalcite compound particles used in Example 1, and 0.1 mol / 16 ml of L sodium hydroxide was mixed in a 250 mL settling tube, and immediately subjected to ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 11.96.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of methanol, 2 g of the aluminum oxide powder used in Example 1, 0.25 g of the synthetic hydrotalcite compound particles used in Example 1, and 16 mL of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube. Immediately after that, an ultrasonic dispersion treatment was performed for 3 minutes to disperse to prepare a polishing slurry. The slurry had a pH of 3.87.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of anhydrous silica (average particle size 15.11 μm / Wako), 0.25 g of the synthetic charcoalmite compound particles used in Example 6 and 16 ml of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube. Immediately after that, an ultrasonic dispersion treatment was performed for 3 minutes to disperse, thereby preparing a polishing slurry. The slurry had a pH of 3.88.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of anhydrous silica used in Example 12, 0.5 g of the anionic surfactant 2, 0.25 g of synthetic hydrotalcite compound particles used in Example 1, and 0.1 mol / L 16 ml of sodium hydroxide was mixed in a 250 mL settling tube and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 11.57.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of cerium oxide (average particle size 1.7 μm, purity 60%, trade name: TE-508 / Seimi Chemical), 0.5 g of the anionic surfactant 2 and the synthetic hydro used in Example 1 0.5 g of talcite compound particles and 16 ml of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube and immediately subjected to ultrasonic dispersion treatment for 3 minutes to disperse to prepare a polishing slurry. The slurry had a pH of 3.13.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of cerium oxide used in Example 14, 0.5 g of the anionic surfactant 2, 0.5 g of Li-Al hydrotalcite compound used in Example 7, and 0.1 mol / 16 ml of L sodium hydroxide was mixed in a 250 mL settling tube, and immediately subjected to ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The pH of this slurry was 10.11.
Table 1 shows the results obtained by allowing the prepared sedimentation tube containing the slurry to stand at room temperature and evaluating the sedimentation rate and resuspension by the method described below.

(Dispersibility of pharmaceutical aluminum gel solution)
At room temperature, glycerin 200 mL, dry aluminum hydroxide gel (average particle size 3.5 μm / Kyowa Chemical Industry Co., Ltd.) 30 g, synthetic hydrotalcite compound particles 16 g used in Example 1, and 0.1 mol / L of quencher 16 ml of acid was mixed in a 250 mL settling tube and immediately dispersed by ultrasonic dispersion for 3 minutes to prepare a pharmaceutical aluminum gel solution. The pH of this aluminum gel solution was 3.84.
The prepared sedimentation tube containing the aluminum gel solution is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of pharmaceutical aluminum gel solution)
At room temperature, 200 mL of water, 30 g of the dried aluminum hydroxide gel used in Example 16, and 16 g of the synthetic hydrotalcite compound particles used in Example 1 and 16 ml of 0.1 mol / L citric acid were placed in a 250 mL settling tube. The mixture was immediately dispersed by ultrasonic dispersion for 3 minutes to prepare a pharmaceutical aluminum gel solution. The pH of this aluminum gel solution was 3.84.
The viscosity of the slurry was measured and found to be 1.8 cP (27.0 ° C.). Even though the viscosity of ion-exchanged water measured by the same method was 1.8 cP, no increase in viscosity was observed.
The prepared sedimentation tube containing the aluminum gel solution is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of pharmaceutical aluminum gel solution)
At room temperature, 200 mL of glycerin, 30 g of dry aluminum hydroxide gel used in Example 16, 27 g of synthetic hydrotalcite compound particles used in Example 1, and 16 mL of 0.1 mol / L citric acid were mixed in a 250 mL settling tube. Immediately, the mixture was dispersed by ultrasonic dispersion for 3 minutes to prepare a pharmaceutical aluminum gel solution. The aluminum gel solution had a pH of 3.86.
The prepared sedimentation tube containing the aluminum gel solution is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of pharmaceutical aluminum gel solution)
At room temperature, 200 mL of water, 30 g of the dried aluminum hydroxide gel used in Example 16, and 8 g of the synthetic hydrotalcite compound particles used in Example 1 and 16 mL of 0.1 mol / L citric acid were placed in a 250 mL settling tube. The mixture was immediately dispersed by ultrasonic dispersion for 3 minutes to prepare a pharmaceutical aluminum gel solution. The pH of this aluminum gel solution was 3.32.
The prepared sedimentation tube containing the aluminum gel solution is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of aqueous pigment suspension)
At room temperature, 200 mL of water, synthetic calcium carbonate (primary particle size 150 nm, trade name: Brilliant-1500 / Shiraishi Kogyo Co., Ltd.) 30 g, 0.5 g of the anionic surfactant 2 and the synthetic hydro used in Example 1 8 g of talcite compound particles and 16 ml of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube, and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare an aqueous pigment suspension. The pH of this aqueous pigment suspension was 3.66.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of aqueous pigment suspension)
At room temperature, 200 mL of water, 30 g of the synthetic calcium carbonate used in Example 18, 0.5 g of the anionic surfactant 2, 8 g of the synthetic charcoalmite compound particles used in Example 6, and 0.1 mol / L of hydroxylated water 16 ml of sodium was mixed in a 250 mL settling tube and immediately dispersed by ultrasonic dispersion for 3 minutes to prepare an aqueous pigment suspension. The pH of this aqueous pigment suspension was 11.28.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of aqueous pigment suspension)
At room temperature, 200 mL of water, 30 g of bentonite (trade name: Osmos N / Shiroishi Kogyo Co., Ltd.), 8 g of the synthetic hydrotalcite compound particles used in Example 1 and 16 ml of 0.1 mol / L hydrochloric acid were placed in a 250 mL settling tube. Were mixed and immediately subjected to ultrasonic dispersion treatment for 3 minutes to prepare an aqueous pigment suspension. The pH of this aqueous pigment suspension was 4.20.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of aqueous pigment suspension)
At room temperature, 200 g of water, 30 g of the synthetic calcium carbonate used in Example 18, 0.5 g of the anionic surfactant 2, 6 g of the synthetic charcoalmite compound particles used in Example 6, and 0.1 mol / L of water An aqueous pigment suspension was prepared by mixing 16 ml of sodium oxide in a 250 mL settling tube and immediately dispersing by ultrasonic dispersion for 3 minutes. The pH of this aqueous pigment suspension was 10.54.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of aqueous pigment suspension)
At room temperature, 200 mL of water, 30 g of bentonite used in Example 22, 6 g of synthetic hydrotalcite compound particles used in Example 1 and 16 mL of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube and immediately for 3 minutes. An aqueous pigment suspension was prepared by dispersing by ultrasonic dispersion treatment. The pH of this aqueous pigment suspension was 3.87.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of wettable powder agricultural chemicals)
At room temperature, 200 mL of water, 0.32 g of cupric hydroxide and 0.08 g of the synthetic charcoalmite compound particles used in Example 6 were mixed in a 250 mL settling tube, and immediately subjected to ultrasonic dispersion treatment for 3 minutes for dispersion. An aqueous pigment suspension was prepared. The pH of this aqueous pigment suspension was 7.20.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of wettable powder agricultural chemicals)
At room temperature, 200 mL of water, 0.32 g of basic copper sulfate, 0.5 g of the anionic surfactant 2 and 0.08 g of the synthetic hydrotalcite compound particles used in Example 1 were mixed in a 250 mL settling tube. Immediately after that, the mixture was dispersed by ultrasonic dispersion for 3 minutes to prepare an aqueous pigment suspension. The pH of this aqueous pigment suspension was 6.20.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement (main component: tricalcium silicate / manufactured by Taiheiyo Cement), 1200 g of Toyoura standard sand, 0.5 g of the anionic surfactant 2 and the synthetic hydrotal used in Example 1 A mortar composition was prepared by mixing 450 g of site compound particles. The pH of this mortar composition was 8.55.
Table 3 shows the results of a flow test performed on the prepared mortar composition based on JIS R5201.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement used in Example 27, 1200 g of Toyoura standard sand, and 450 g of synthetic charcoalmite compound particles used in Example 6 were mixed to prepare a mortar composition. The pH of this mortar composition was 8.28.
Table 3 shows the results of a flow test performed on the prepared mortar composition based on JIS R5201.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement used in Example 27, 1200 g of Toyoura standard sand and 450 g of the Li—Al hydrotalcite compound used in Example 7 were mixed to prepare a mortar composition. The pH of this mortar composition was 8.79.
Table 3 shows the results of a flow test performed on the prepared mortar composition based on JIS R5201.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement used in Example 27, 1200 g of Toyoura standard sand, 0.5 g of the anionic surfactant 2 and 225 g of synthetic hydrotalcite compound particles used in Example 1 A mortar composition was prepared by mixing. The pH of this mortar composition was 8.11.
Table 3 shows the results of a flow test performed on the prepared mortar composition based on JIS R5201.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement used in Example 27, 1200 g of Toyoura standard sand, and 225 g of synthetic charcoalmite compound particles used in Example 6 were mixed to prepare a mortar composition. The pH of this mortar composition was 7.90.
Table 3 shows the results of a flow test performed on the prepared mortar composition based on JIS R5201.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement used in Example 27, 1200 g of Toyoura standard sand and 225 g of the Li—Al hydrotalcite compound used in Example 7 were mixed to prepare a mortar composition. The pH of this mortar composition was 7.71.
Table 3 shows the results of a flow test performed on the prepared mortar composition based on JIS R5201.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the cationic surfactant, and 0.5 g of the synthetic hydrotalcite compound particles used in Example 1 were placed in a 250 mL settling tube. The mixture was mixed and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 8.28.
The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 1 as Comparative Example 1.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the cationic surfactant, and 0.05 g of the synthetic hydrotalcite compound particles used in Example 1 were placed in a 250 mL settling tube. The mixture was mixed and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 8.72.
The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 1 as Comparative Example 2.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the anionic surfactant 1 and 0.05 g of the synthetic hydrotalcite compound particles used in Example 1 were settled for 250 mL. The mixture was mixed in a tube and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The pH of this slurry was 8.12.
The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 1 as Comparative Example 3.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the nonionic surfactant, and 0.05 g of the synthetic hydrotalcite compound particles used in Example 1 were placed in a 250 mL settling tube. The mixture was mixed and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a polishing slurry. The slurry had a pH of 2.31.
The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 1 as Comparative Example 4.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, and 2 g of the cationic surfactant were mixed in a 250 mL settling tube, and immediately dispersed by performing ultrasonic dispersion for 3 minutes. A slurry was prepared. Although the pH of this slurry was 2.43, foaming was observed. The viscosity of this slurry was measured and found to be 3.2 cP (27.0 ° C.). An increase in viscosity was observed compared to the viscosity of ion-exchanged water measured by the same method was 1.8 cP.
The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 1 as Comparative Example 5.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, and 0.5 g of the nonionic surfactant were mixed in a 250 mL settling tube and immediately subjected to ultrasonic dispersion treatment for 3 minutes to be dispersed. A polishing slurry was prepared. The pH of this slurry was 2.40.
The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 1 as Comparative Example 6.

(Dispersibility of polishing slurry)
At room temperature, 200 mL of water, 2 g of the aluminum oxide powder used in Example 1, 0.5 g of the anionic surfactant 2 and synthetic hydrotalcite compound particles (average particle size: 5.0 μm: KW-1100 / Kyowa Chemical) Industrial Co., Ltd. (0.05 g) and 0.1 mol / L hydrochloric acid (16 ml) were mixed in a 250 mL settling tube and immediately subjected to ultrasonic dispersion for 3 minutes to disperse to prepare a polishing slurry. The slurry had a pH of 3.92.
The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 1 as Comparative Example 7.
As in this example, when the average particle size of the dispersant is larger than the average particle size of the dispersed phase, the effect as a suspension stabilizer is not exhibited.

(Dispersibility of pharmaceutical aluminum gel solution)
At room temperature, 200 mL of glycerin, 30 g of the dried aluminum hydroxide gel used in Example 16, 0.5 g of the anionic surfactant 2, 4 g of synthetic hydrotalcite compound particles used in Example 1, and 0.1 mol / L of citric acid (16 ml) was mixed in a 250 mL settling tube and immediately dispersed by ultrasonic dispersion for 3 minutes to prepare a pharmaceutical aluminum gel solution. The pH of this aluminum gel solution was 4.6.
The prepared sedimentation tube containing the aluminum gel solution is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2 as Comparative Example 8.

(Dispersibility of pharmaceutical aluminum gel solution)
At room temperature, 200 mL of water, 30 g of dry aluminum hydroxide gel used in Example 16, and 0.8 g of synthetic hydrotalcite compound particles used in Example 1 and 16 ml of 0.1 mol / L citric acid were precipitated for 250 mL. The mixture was mixed in a tube and immediately subjected to an ultrasonic dispersion treatment for 3 minutes to be dispersed to prepare a pharmaceutical aluminum gel solution. The pH of this aluminum gel solution was 4.55.
The prepared sedimentation tube containing the aluminum gel solution is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2 as Comparative Example 9.

(Dispersibility of aqueous pigment suspension)
At room temperature, 200 mL of water, 30 g of synthetic calcium carbonate used in Example 18, 0.5 g of the anionic surfactant 2, 0.8 g of synthetic charcoalmite compound particles used in Example 6, and 0.1 mol / L An aqueous pigment suspension was prepared by mixing 16 ml of sodium hydroxide in a 250 mL settling tube and immediately dispersing by ultrasonic dispersion for 3 minutes. The pH of this aqueous pigment suspension was 11.11.
The prepared sedimentation tube containing the aqueous pigment suspension is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2 as Comparative Example 10.

(Dispersibility of aqueous pigment suspension)
At room temperature, 200 mL of water, 30 g of bentonite used in Example 22, 0.8 g of synthetic hydrotalcite compound particles used in Example 1 and 16 ml of 0.1 mol / L hydrochloric acid were mixed in a 250 mL settling tube, and immediately An aqueous pigment suspension was prepared by dispersing for 3 minutes by ultrasonic dispersion. The pH of this aqueous pigment suspension was 4.16.
The prepared sedimentation tube containing the aqueous pigment suspension is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2 as Comparative Example 11.

(Dispersibility of wettable powder agricultural chemicals)
At room temperature, 200 mL of water and 0.32 g of cupric hydroxide were mixed in a 250 mL settling tube and immediately subjected to ultrasonic dispersion treatment for 3 minutes to disperse to prepare an aqueous pigment suspension. The pH of this aqueous pigment suspension was 6.90.
The prepared sedimentation tube containing the aqueous pigment suspension was allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2 as Comparative Example 12.

(Dispersibility of wettable powder agricultural chemicals)
At room temperature, 200 mL of water, 0.32 g of basic copper sulfate, and 0.5 g of the anionic surfactant 2 were mixed in a 250 mL settling tube, and immediately subjected to ultrasonic dispersion treatment for 3 minutes to be dispersed. A pigment suspension was prepared. The pH of this aqueous pigment suspension was 5.90.
The prepared sedimentation tube containing the aqueous pigment suspension is allowed to stand at room temperature, and the results of evaluating the sedimentation rate and resuspension by the method described later are shown in Table 2 as Comparative Example 13.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement used in Example 27, 1200 g of Toyoura standard sand, 450 g of the anionic surfactant 1 and 40 g of the synthetic hydrotalcite compound particles used in Example 1 were mixed. To prepare a mortar composition. The pH of this mortar composition was 8.39, and some foaming was observed.
Table 3 shows the results of a flow test performed on the prepared mortar composition based on JIS R5201, as Comparative Example 14.

(Dispersibility of mortar composition)
At room temperature, 400 mL of water, 600 g of ordinary Portland cement used in Example 27, 1200 g of Toyoura standard sand, and 450 g of the anionic surfactant 2 were mixed to prepare a mortar composition. The pH of this mortar composition was 8.06 and some foaming was observed.
The prepared mortar composition is subjected to a flow test based on JIS R5201, and the results are shown in Table 3 as Comparative Example 15.

In Examples 1 to 26, foaming and an increase in the viscosity of the slurry were not observed, and it can be said that the sedimentation rate was a satisfactory level at 0.2 mm / hr. Moreover, although the sedimentation layer was re-dispersed by shaking, in Example Comparative Examples 37, 38, 41, 44, and 45, most of the sedimentation layer remained even by shaking. Moreover, in the comparative example, the sedimentation speed may exceed 0.2 mm / hr, and in Examples 37, 46 and 47, further foaming or viscosity increase was observed.
In the flow test on the mortar composition, the flow values are greatly different between Examples 27 to 32 and Examples 46 and 47, and the former suspension composition of the present invention is clearly superior in dispersibility.

From the above examples, the suspension composition of the present invention contains a small amount of hydrotalcite or charcoalumite, so that it does not have undesirable properties such as viscosity increase, foaming, and cost increase, and uniform inorganic fine particles. It can be seen that the dispersibility, the long-term stability of the uniform dispersion state, and the redispersibility are improved.

The analysis and testing method and apparatus will be described below.

(1) Sedimentation rate measurement method: The prepared sedimentation tube containing the slurry is allowed to stand at room temperature, and the University of Chemistry Dictionary, Reprinted Edition, Volume 5, p. 981 (Kyoritsu Publishing Co., Ltd., issued on March 20, 1967) The height of the interface between the A layer (clarified liquid layer), B layer (suspension layer) and D layer (sedimentation) Of these, the change rate of the interface height between layer A (clarified liquid layer) and layer B (suspension layer), that is, the sedimentation interface height, with respect to time

(Initial sedimentation interface height-sedimentation interface height after time T) / elapsed time T

Was determined as the sedimentation velocity (mm / hr).

(2) Redispersibility method: The settling tube containing the prepared slurry was allowed to stand at room temperature for 6 months, and the dispersion state after lightly shaking 5 times by hand was confirmed.
Evaluation: The dispersion state of the slurry was evaluated in the following three stages.
○
・ ・ ・ ・ Disperse uniformly.
△ ・ ・ ・ ・ Dispersed, but some sedimentation remains.
× ··· Most of the sedimentation remains.

(3) Viscosity measuring device: Programmable digital viscometer DV-2 + (Brookfield)
Spindle LV1 Rotation speed 30rpm
Method: The prepared slurry was placed in a tall beaker and the viscosity and temperature were measured.

Claims (5)

In a liquid dispersion medium in which inorganic fine particles (component a) are dispersed, at least one inorganic hydroxide particle selected from the group consisting of hydrotalcite compounds and synthetic charcoalmite, and an average particle diameter larger than that of the inorganic fine particles Particles (component b) , and at least one anionic polymer surfactant selected from anionic polymer surfactants, the amount of component b relative to the amount of component a (= the amount of component b / A suspension composition having suspension stability, which is blended so that the blending amount of component a) is in the range of 0.1 to 1.0 by weight . The suspension composition according to claim 1 , wherein the liquid dispersion medium is water, an organic dispersion medium, or a mixture thereof. The suspension composition according to claim 2 , wherein the organic dispersion medium is at least one selected from ethanol, ethylene glycol, or glycerin. Inorganic fine particles are magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium silicate, aluminum hydroxide, fumed silica, cerium oxide, α-alumina, silicon carbide, boron carbide, dimanganese trioxide, manganese trioxide, calcium carbonate , Barium sulfate, cobalt oxide, bismuth vanadate, titanium oxide, cerium hydroxide, zinc hydroxide, iron oxide, iron hydroxide, cupric hydroxide, basic copper sulfate, basic magnesium carbonate, aluminum silicate, clay, The suspension composition according to claim 1, 2 or 3, wherein the suspension composition is at least one selected from lime, cement, mortar, concrete, talc, clay, zeolite, and bentonite. The anionic polymer surfactant is at least one selected from polycarboxylic acid-based, naphthalene-based, melamine-based, and aminosulfonic acid-based surfactants. Suspension composition.