JP2014205623A - Method of producing aqueous thickener for teeth bleaching material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing an aqueous thickener for a teeth bleaching material in a short time efficiently, the thickener being uniformly dispersed with titanic oxide, the thickener containing adequately thickened titanic oxide in which generation of undissolved lump being suppressed and an organic thickener.SOLUTION: A method of producing an aqueous thickener for a teeth bleaching material is provided, the thickener containing titanic oxide having photocatalytic action and an organic thickener. The method comprising the processes of: mixing titanic oxide with an aqueous solution containing 65 to 90 mass% of polyalcohol; mixing an organic thickener with a mixed aqueous solution containing the polyalcohol obtained in the prior process and titanic oxide; and adjusting the pH of the aqueous thickener obtained in the prior process.

Description

  The present invention is a method for easily producing a thickening solution for tooth bleaching material containing titanium oxide which is uniformly dispersed for the purpose of tooth aesthetics and anti-aging, suppresses generation of spatter and is moderately thickened. About.

In recent years, in dental practice, there has been a strong demand for improvement of so-called aesthetics such as tooth shape, arrangement, and harmony. As a method for improving the aesthetics of a discolored tooth, several methods have been proposed in the past. Among them, a bleaching method (bleaching) is a treatment method with less burden such as shaving teeth. Yes, this treatment method can be said to be an excellent treatment method with high preservation of the tooth quality. This bleaching method is basically a method of removing a colored substance by a chemical reaction. Conventionally, the bleaching method for vital teeth and the non-vital bleaching method are mainly used. Dental bleaching materials comprising various chemical agents and bleaching methods using the same have been reported.
The bleaching materials used for tooth bleaching require many conditions such as a remarkable bleaching effect, simple work, and the appearance of a bleaching effect in a short period of time. 20 to 35% by weight of hydrogen peroxide, which is strong, was basically used for bleaching by its oxidizing action.

  In view of the current state of the bleaching method and bleaching material as described above, Patent Document 1 discloses a safe bleaching material and bleaching method using photocatalytic titanium oxide, and Patent Document 2 is safer and superior in simplicity. As a bleaching material having a high bleaching effect and a bleaching method thereof, a bleaching material and a bleaching method in which titanium oxide having a photocatalytic action and a low-concentration hydrogen peroxide solution are used in combination have been proposed.

  Furthermore, in Patent Document 3, as a method for stably storing the bleaching material described in Patent Document 2 for a long period of time, an aqueous mixture (solution 1) of an inorganic thickener and a titanium oxide that generates a photocatalytic action and peroxidation in an aqueous solution. It has been reported that it is effective to make a two-component type with a mixed aqueous solution (solution 2) of a compound that generates hydrogen, phosphoric acid and condensed phosphate.

On the other hand, in the conventional tooth bleaching, since it has been the mainstream to perform the bleaching process for each tooth, a tooth bleaching material having a fluid viscosity that allows easy application and wiping of the bleaching material has been preferred and used. However, in recent years, a multi-tooth batch irradiation lamp has appeared as a light irradiator used together with bleaching materials during bleaching treatment, and many teeth coated with bleaching materials such as 6 teeth, 8 teeth, 12 teeth and 14 teeth are lighted at once. A method of bleaching by irradiation, a method of using a light irradiator having a higher light intensity, and the like have been proposed. A bleaching material containing titanium oxide has (1) high adhesion and retention on the tooth surface, (2 It is difficult to dry, and (3) a bleaching material in which titanium oxide is uniformly dispersed has been demanded in order to exhibit sufficient catalytic ability of titanium oxide blended as a photocatalyst. For such problems, Patent Document 4 proposes a method containing an organic thickener, and Patent Document 5 proposes a method containing an organic thickener and an inorganic clay mineral.
Dental thickeners containing organic thickeners and organic thickeners and inorganic clay minerals are required to be highly viscous aqueous solutions that do not cause dripping from attached teeth, but are commercially available Organic thickeners are often in the form of powder, so when dissolved in water, they tend to generate spatter (lumps encased in an impermeable layer with high viscosity), resulting in uneven distribution of titanium oxide. There was a high possibility that sufficient bleaching effect was not obtained. In the above-mentioned patent documents of tooth bleaching materials containing an organic thickener or the like, an efficient method for producing tooth bleaching materials focusing on uniform dispersion of titanium oxide and suppression of spatter generation was not specified.

Japanese Patent Application Laid-Open No. 2004-083389 Japanese Patent No. 3030380 JP 2002-220330 A Japanese Patent No. 4903943 Japanese Patent No. 4910380

  An object of the present invention is to provide a thickening solution for tooth bleaching materials containing titanium oxide and an organic thickener in which the titanium oxide is uniformly dispersed and moderately thickened by suppressing the generation of spatter in the tooth bleaching material. The object is to provide a method for efficiently producing in a short time.

  As a result of intensive research on the above problems, the inventors of the present invention have prepared a mixture of titanium oxide and an organic thickener in a method for producing a thickening solution for tooth bleaching material containing titanium oxide having a photocatalytic action and an organic thickener. At that time, by using a polyhydric alcohol aqueous solution prepared at a predetermined concentration, and further mixing and preparing a polyhydric alcohol aqueous solution, titanium oxide, and an organic thickener in a predetermined step, titanium oxide is uniformly dispersed, and The present inventors have found that a thickening solution for tooth bleaching material that is moderately thickened by suppressing generation of spatter can be easily produced.

That is, this invention is a manufacturing method of the thickening liquid for tooth bleaching materials containing the titanium oxide which has a photocatalytic action, and an organic thickener, Comprising: The tooth bleaching characterized by having the following processes (1)-(3) It is a manufacturing method of the thickening liquid for materials.
(1): Step of mixing titanium oxide with an aqueous solution containing 65 to 90% by mass of polyhydric alcohol (2): Mixed aqueous solution containing polyhydric alcohol and titanium oxide obtained in step (1), and organic thickener Step (3) of mixing the step: Adjusting the pH of the thickened liquid obtained in Step (2) to 5 to 12

  According to the present invention, in the method for producing a thickening liquid for tooth bleaching material containing titanium oxide having a photocatalytic action and an organic thickener, titanium oxide is uniformly dispersed, and generation of spatter is suppressed, and A thickening solution for tooth bleaching material thickened to an appropriate viscosity can be produced efficiently. Furthermore, the tooth bleaching material using the thickening solution for tooth bleaching material manufactured by the method of the present invention has an appropriate viscosity, so that it has high adhesion and retention on the tooth surface, is difficult to dry, and has titanium oxide. Since it is uniformly dispersed, the photocatalytic ability of titanium oxide can be sufficiently expressed.

The present invention is described in detail below.
<Manufacture of thickener for tooth bleaching material>
The present invention includes a step (1) for producing an aqueous solution in which titanium oxide is uniformly dispersed, a step (2) for mixing the titanium oxide-dispersed aqueous solution obtained in step (1) and an organic thickener, and step (2). It is a manufacturing method which has the process (3) which adjusts the pH of the thickening liquid obtained by.

<Step (1)>
Step (1) in the present invention is a step of mixing an aqueous solution containing 65 to 90% by mass, preferably 69 to 87% by mass of polyhydric alcohol, and titanium oxide. The content (% by mass) of the polyhydric alcohol is represented by the mass of the polyhydric alcohol relative to the total mass of the polyhydric alcohol and water in the aqueous polyhydric alcohol solution in step (1). When titanium oxide is dispersed in a polyhydric alcohol aqueous solution containing 65 to 90% by mass of polyhydric alcohol, the generation of spatter is suppressed, and further the solubility of the organic thickener in step (2) is improved. An organic thickener can be uniformly dispersed and thickened.
When the polyhydric alcohol is less than 65% by mass, the behavior is similar to that when the polyhydric alcohol is not used (for example, when only water is used), and there is much generation of spatter derived from the organic thickener, and once more. Dissolved powder is very slow to dissolve, and mixing for a very long time is required for uniform dissolution. Further, when the polyhydric alcohol exceeds 90% by mass, it takes time to dissolve the organic thickener, and it takes 12 hours or more to uniformly dissolve it, which is not suitable as an industrial production method. In addition, when titanium oxide is mixed with 100% polyhydric alcohol, the organic thickener is originally added to and dissolved in the polyhydric alcohol with high viscosity. Therefore, titanium oxide cannot be uniformly mixed.

  Preparation of the aqueous solution containing the polyhydric alcohol in step (1) may be performed in the stirring device used in step (1), or may be prepared outside the stirring device and then charged into the stirring device. Is not to be done. What is necessary is just to be able to adjust to the predetermined | prescribed polyhydric alcohol density | concentration at the time of mixing stirring of the aqueous solution containing a polyhydric alcohol, and a titanium oxide. In addition, the order in which the aqueous solution containing polyhydric alcohol and titanium oxide are charged into the stirrer is not particularly limited, and the polyhydric alcohol, water and titanium oxide are separately charged in the stirrer and then stirred and mixed. Alternatively, after adding the polyhydric alcohol aqueous solution in the stirring apparatus, titanium oxide may be added or vice versa, or a combination of the above procedures may be used. According to the present invention, even when polyhydric alcohol, water, and titanium oxide are charged all at once in the stirring device, uniform mixing is possible, and the working efficiency is remarkably improved.

The stirrer used in step (1) of the present invention is not particularly limited, but a stirrer capable of sufficiently mixing and stirring the target solution to be mixed is desirable, and a stirrer having a stirring blade such as an anchor type, and a planetary stirrer Etc. are preferred.
The planetary stirring device is a device that can mix and stir the composition without using a stirring bar / blade or a vacuuming device by rotating the container containing the composition to be mixed while revolving. In addition to stirring and kneading, it is possible to simultaneously perform defoaming that requires treatment depending on the product, and both steps of stirring and mixing and defoaming can be performed simultaneously. For example, when a planetary stirrer is used, the rotational speed of revolution and rotation varies depending on the size of the apparatus and the amount of the composition, but it is usually used at about 500 to 1500 rpm and about 200 to 1000 rpm. Examples of the planetary stirring device include Mazerustar kk-400 and kk-5000 manufactured by Kurabo Industries. The material used for the stirring and mixing is not particularly limited, such as plastic or SUS, but a material with less foreign matter is more preferable.

  The polyhydric alcohol used in the present invention is usually liquid and includes highly safe glycerin, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, sorbitol, mannitol, etc. However, it is not limited to these. Among these, preferred polyhydric alcohols are glycerin, ethylene glycol, and polyethylene glycol. These can be obtained relatively inexpensively, have a moderate viscosity, and have good workability. The water used in the present invention is preferably purified water, and more preferably a standard product such as the Japanese Pharmacopoeia with high safety.

  As the titanium oxide used in the present invention, any titanium oxide capable of producing a photocatalytic action can be used regardless of its form and properties, and preferably any one of anatase type, rutile type and brookite type. It is. In addition, by coating calcium phosphate on the surface of anatase type, rutile type or brookite type titanium oxide, the affinity with the tooth surface has been improved, titanium or iron or iron ion, copper or copper ion, platinum, etc. Those having improved photocatalytic activity by supporting them, or those showing photocatalytic action in response to light in the visible light region by performing plasma treatment or the like on titanium oxide can also be used.

  In the present invention using an aqueous solution containing a polyhydric alcohol having a predetermined concentration, titanium oxide in a powder state can be used as it is because the dispersibility of titanium oxide is good. As a result, there is no need for a step of previously dispersing titanium oxide in a powder state in a medium such as water, so that the working efficiency is remarkably improved. Of course, a sol state in which powdered titanium oxide is dispersed in a medium such as water may be used in the present invention as long as the effect of the present invention is not impaired.

The particle diameter of titanium oxide is preferably 1 to 500 nm, more preferably 5 to 200 nm. The amount of titanium oxide is preferably 0.001 to 10% by mass, more preferably 0.01 to 1% by mass, and still more preferably 0.001% by mass, based on the total mass of the thickener for tooth bleaching material. 01-0.5 mass%.

<Step (2)>
Step (2) of the present invention is a step of mixing an organic thickener with a mixed aqueous solution containing the polyhydric alcohol and titanium oxide obtained in step (1). The stirring device used in the step (2) is not particularly limited as long as it is a device that can sufficiently mix and stir the target solution to be mixed. However, the same stirring as in the step (1) is considered in consideration of work efficiency and contamination. It is desirable to use an apparatus. For example, when a planetary stirrer is used in the step (2), the rotation speed of revolution and rotation varies depending on the size of the apparatus and the amount of the composition, but it is usually used at about 500 to 1500 rpm and about 200 to 1000 rpm.

The organic thickener used in the present invention is a water-soluble polymer, and preferably a food additive is used from the viewpoint of safety. As examples, one or more of sodium carboxymethylcellulose, carboxymethylcellulose calcium and polyacrylic acid or salts thereof, carboxyvinyl polymer which is an acrylic acid-based polymer, and the like can be used, but the invention is not limited thereto. Among these, preferred organic thickeners are sodium carboxymethylcellulose and carboxyvinyl polymer. These are highly safe and have a relatively high stability when a container containing hydrogen peroxide water is present. These organic thickeners are usually sold as powders. In the present invention, since the dispersibility of the organic thickener is good, the powdered organic thickener can be used as it is. Of course, under conditions that do not impair the effects of the present invention, a mixed aqueous solution containing the polyhydric alcohol and titanium oxide obtained in step (1) after dissolving the organic thickener in powder in a medium such as water. You may add to.

The blending amount of the organic thickener is adjusted so that the tooth bleaching material using the thickening solution for tooth bleaching material of the present invention has a desired viscosity. The blending amount of the organic thickener is preferably 0.1 to 10% by mass and more preferably 1 to 5% by mass with respect to the total mass of the image mucus for tooth bleaching material.

  In the step (2) of the present invention, an inorganic clay mineral may be mixed in addition to the organic thickener. In general, inorganic clay minerals include fibrous structure types (eg, sepiolite, apatalite, etc.), amorphous structure types (eg, allophane, etc.), mixed layer structure types (eg, kaolinite, montmorillonite, etc.) Broadly divided into structural types. Inorganic clay minerals include dicalite, nacrite, kaolinite, anoxite, halloysite, metahalosite, chrysotile, lizardite, serpentine, antigolite, beidellite, montmorillonite, sauconite, stevensite, nontronite, saponite, hectorite. , Vermiculite, smectite, sepiolite, nectite, illite, sericite, marine stone-montmorillonite, rholite-montmorillonite, chlorite-vermiculite, illite-montmorillonite, halloysite-montmorillonite, kaolinite-montmorillonite, etc. Species or two or more can be used. Among these, montmorillonite, saconite, smectite, stevensite, beidellite, nontronite, saponite, hectorite, vermiculite, nectite and sepiolite are preferable. These may be natural products or synthetic products. Synthetic products include synthetic sodium magnesium silicate lithium (Laponite) and the like. The blending amount of the inorganic clay mineral is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total mass of the image mucus for tooth bleaching material.

<Step (3)>
Step (3) of the present invention is a step of adjusting the pH of the thickened liquid obtained in step (2). The pH of the thickening liquid adjusted in the step (3) is 5 to 12, preferably 7 to 12, and more preferably 8 to 11. By adjusting the pH of the thickening liquid to the above range, it is possible to make it higher than the critical pH (pH = 5) at which the teeth are decalcified, and further improve the bleaching effect when mixed with an aqueous hydrogen peroxide solution. Can do.
When the pH of the thickening liquid obtained in the step (2) is out of the above range, the pH is adjusted using an acid or a base. For example, when the pH of the thickening liquid falls below the above range due to the organic thickener used in step (2), the aqueous solution containing a basic compound may be adjusted to a predetermined pH by adding the aqueous solution containing the basic compound to the thickening liquid. it can. In step (3), the pH of the thickening liquid can be adjusted by adding water.

  Examples of basic compounds used in the present invention include sodium hydroxide, potassium hydroxide, calcium hydroxide, 4 sodium pyrophosphate, 4 potassium pyrophosphate, sodium polyphosphates, potassium polyphosphates, trisodium phosphate, phosphorus Although tripotassium acid etc. are contained, it is not a thing limited to these. Among these, preferable basic compounds are sodium hydroxide and tetrasodium pyrophosphate. These can be obtained inexpensively and are useful. Further, the basic compound is more preferably a food additive standard product.

  Although the temperature at the time of stirring and mixing in each process of the present invention is not particularly limited, it can be performed at 10 to 90 ° C. at which a stirrable viscosity is obtained, and 20 to 60 ° C. is more preferable. When the temperature exceeds 90 ° C., the evaporation of water increases, and it becomes difficult to secure a predetermined amount of water. If it is less than 10 degreeC, a viscosity will become low at the time of thickener addition, and stirring efficiency will fall.

<Tooth bleaching material>
The thickening solution for tooth bleaching material in which the titanium oxide obtained by the production method having the steps (1) to (3) is uniformly dispersed contains hydrogen peroxide and / or a compound that generates hydrogen peroxide. Used as a tooth bleaching material by mixing with aqueous solution.

  The compound that generates hydrogen peroxide used in the present invention may be any compound that can generate hydrogen peroxide when made into an aqueous solution, such as perborate, percarbonate, perphosphate, persulfate. Salts, calcium peroxide, magnesium peroxide, urea peroxide and the like can be mentioned, and urea peroxide is preferred.

  The concentration of hydrogen peroxide in the tooth bleaching material obtained by mixing the thickening solution for tooth bleaching material of the present invention and an aqueous solution containing hydrogen peroxide and / or a compound capable of generating hydrogen peroxide is 35% by mass or less, preferably 1 to 10% by mass. Even if the content is higher than this range, there is no significant difference in the bleaching effect, and it is not advantageous from the viewpoint of safety.

The aqueous solution containing hydrogen peroxide and / or a compound capable of generating hydrogen peroxide of the present invention may contain phosphoric acid and / or condensed phosphate as a stabilizer and a bleaching accelerator. Examples of phosphoric acid include orthophosphoric acid, and examples of condensed phosphate include pyrophosphoric acid, potassium salt of tripolyphosphoric acid, sodium salt, and the like, and tetrasodium pyrophosphate is particularly preferable.
The blending amount of phosphoric acid is preferably 0.1 to 10% by weight, more preferably 0.2 to 2% by weight in the tooth bleaching material. When the amount is less than this range, the effect is small, and when it is high, the acidity of the bleaching material becomes strong, causing problems such as adversely affecting the tooth surface. The blending amount of the condensed phosphate is preferably 0.1 to 10% by weight and more preferably 0.5 to 5% by weight in the tooth bleaching material. When the amount is less than this range, the effect is small, and when the amount is large, the liquidity of the bleaching material becomes alkaline, and the stability of hydrogen peroxide decreases.

  The viscosity of the tooth bleaching material of the present invention is adjusted to a viscosity range that does not sag from the patient's teeth. Preferably it is 1,000-100,000 mPa * s, More preferably, it is 2,000-80,000 mPa * s. When the viscosity is within this range, the bleaching material does not sag even when applied to the tooth surface having an angle of 45 degrees with respect to the horizontal plane.

As a method for adhering the tooth bleaching material of the present invention to the tooth surface, a method of directly applying the tooth bleaching material to the tooth surface is exemplified as a suitable one. Further, the bleaching of the discolored tooth is performed by applying the above-mentioned tooth bleaching material to the tooth surface and repeating the treatment of irradiating light one or more times, preferably a plurality of times. The light used at this time is preferably light having a wavelength that can be absorbed by titanium dioxide and can cause a photocatalytic action, and has a wavelength that has little adverse effect on the human body. As such a wavelength, light including a wavelength of 300 nm or more, more preferably light including a wavelength of 380 to 500 nm is used. If it is larger than 500 nm, the temperature rise of the tooth increases, which is not preferable. Examples of the light source used in the present invention include exothermic lamps, fluorescent lamps, halogen lamps, black lights, metal halide lamps, xenon lamps, mercury lamps, UV lamps, LEDs (light emitting diodes), and semiconductor lasers. Bleaching is performed by irradiating the surface of the tooth coated with a bleaching material with light from these light sources after cutting unnecessary wavelengths through a suitable filter and then guiding the light by suitable means. It can be performed. The frequency | count of these application | coating and light irradiation can be suitably adjusted according to the grade of a discoloration degree. When performing the adhesion operation such as the application of the bleaching material, it is usually sufficient to deposit a new composition every about 15 to 20 minutes, and the interval and frequency are appropriately set according to the state of the tooth. Can do. The tooth bleaching material of the present invention is effective for bleaching both unmyelinated and myelinated teeth, and exhibits a remarkable effect in bleaching those teeth safely and simply.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention does not receive a restriction | limiting at all to a following example.

Example 1
Mazerustar kk-400 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 400 mL plastic container filled with 77.4 g of glycerin, 12.0 g of purified water, and 0.7 g of titanium oxide was set on a Mazerustar, and stirred and mixed for 3 minutes at revolution 540 rpm and rotation 238 rpm (step (1)). Next, the plastic container was taken out and 5.8 g of carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added. Then, the plastic container was set in the Mazerustar again and stirred for 30 minutes at revolution 540 rpm and rotation 238 rpm. Mixed (step (2)). Subsequently, the plastic container was taken out again, 104.4 g of 4.2% sodium hydroxide aqueous solution was added, and then the plastic container was set on the Mazerustar again and stirred and mixed for 177 minutes at revolution 540 rpm and rotation 238 rpm (step (3): increase Mucus pH 11). Total stirring time is 210 minutes. A thick white cream-like thickener for tooth bleaching material was obtained.

Example 2
Mazerustar kk-400 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 400 mL plastic container filled with 77.4 g of glycerin, 34 g of purified water, and 0.7 g of titanium oxide was set on a Mazerustar, and stirred and mixed for 3 minutes at revolution 540 rpm and rotation 238 rpm (step (1)). Next, the plastic container was taken out and 5.8 g of carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added. Then, the plastic container was set in the Mazerustar again and stirred for 30 minutes at revolution 540 rpm and rotation 238 rpm. Mixed (step (2)). Subsequently, the plastic container was taken out again, 82.4 g of a 5.3% sodium hydroxide aqueous solution was added, and the plastic container was set again on the Mazerustar, and stirred and mixed for 177 minutes at revolution 540 rpm and rotation 238 rpm (step (3)). : PH of thickener 11). Total stirring time is 210 minutes. A thick white cream-like thickener for tooth bleaching material was obtained.

Example 3
Mazerustar kk-5000 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 5000 mL plastic container filled with 972 g of glycerin, 250 g of purified water, and 8.7 g of titanium oxide was set in a Mazerustar, and stirred and mixed for 3 minutes at revolution 528 rpm and rotation 290 rpm (step (1)). Next, the plastic container was taken out, 72 g of carboxyvinyl polymer (Hibiswako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added, and then the plastic container was set again on the Mazerustar and stirred and mixed at 528 rpm and 290 rpm for 30 minutes. (Step (2)). Subsequently, the plastic container was taken out again, and after adding 1200 g of 4.6% aqueous sodium hydroxide solution, the plastic container was set again on the Mazerustar and stirred and mixed at 528 rpm and 290 rpm for 120 minutes (step (3)) : PH of thickener 11). Total stirring time is 153 minutes. A thick white cream-like thickener for tooth bleaching material was obtained.

Example 4
A 200 mL three-necked flask equipped with a stirrer having an agitator blade as an anchor type was charged with 77.4 g of glycerin, 12.0 g of purified water, and 0.7 g of titanium oxide, and stirred and mixed at 300 rpm for 30 minutes (step (1)). ). After the stirring rotation speed was set to 100 rpm, 5.8 g of carboxyvinyl polymer (Hibiswako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added with a glass funnel, and the mixture was stirred at 100 rpm for 60 minutes and then at 300 rpm for 30 minutes ( Step (2)). Next, after the rotational speed of stirring was set to 100 rpm, 104.4 g of 4.2% sodium hydroxide aqueous solution was added with a glass funnel, followed by stirring and mixing at 100 rpm for 30 minutes and then at 400 rpm for 60 minutes (step (3): increase Mucus pH 11). Total stirring time is 210 minutes. A thick white cream-like thickener for tooth bleaching material was obtained.

Example 5
A 200 mL three-necked flask equipped with a stirrer having an agitator blade as an anchor type was charged with 77.4 g of glycerin, 12.0 g of purified water, and 0.7 g of titanium oxide, and stirred and mixed at 300 rpm for 30 minutes (step (1)). ). After the stirring rotation speed was set to 100 rpm, 5.8 g of sodium carboxymethylcellulose (CMC Daicel (manufactured by Daicel Kogyo Co., Ltd.)) was added with a glass funnel, and the mixture was stirred at 100 rpm for 60 minutes and subsequently at 300 rpm for 30 minutes (step (2 )). Next, after the rotational speed of stirring was set to 100 rpm, 104.4 g of purified water was added with a glass funnel, and the mixture was stirred and mixed at 100 rpm for 30 minutes and then at 400 rpm for 60 minutes (step (3): pH 8 of the thickening solution). Total stirring time is 210 minutes. A thick white cream-like thickener for tooth bleaching material was obtained.

Comparative Example 1
Mazerustar kk-400 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 400 mL plastic container filled with 77.4 g of glycerin, 4.1 g of purified water, and 0.7 g of titanium oxide was set on a Mazerustar, and stirred and mixed for 3 minutes at revolution 540 rpm and rotation 238 rpm (step (1)). Next, the plastic container was taken out and 5.8 g of carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added. Then, the plastic container was set in the Mazerustar again and stirred for 30 minutes at revolution 540 rpm and rotation 238 rpm. Mixed (step (2)). Subsequently, the plastic container was taken out again, 112.5 g of a 3.8% aqueous sodium hydroxide solution was added, and then the plastic container was set in the Mazerustar again, and stirred and mixed for 317 minutes at revolution 540 rpm and rotation 238 rpm (step (3)) : PH of thickener 10). A thick white cream-like thickener for tooth bleaching material was obtained.

Comparative Example 2
Mazerustar kk-400 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 400 mL plastic container filled with 77.4 g of glycerin, 51.6 g of purified water, and 0.7 g of titanium oxide was set on a Mazerustar, and stirred and mixed for 3 minutes at revolution 540 rpm and rotation 238 rpm (step (1)). Next, the plastic container was taken out and 5.8 g of carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added. Then, the plastic container was set in the Mazerustar again and stirred for 30 minutes at revolution 540 rpm and rotation 238 rpm. Mixed (step (2)). Subsequently, the plastic container was taken out again and 64.5 g of a 6.8% aqueous sodium hydroxide solution was added. Then, the plastic container was set in the Mazerustar again and stirred and mixed for 317 minutes at revolution 540 rpm and rotation 238 rpm (step (3)). : PH of thickener 11). A thick white cream-like thickener for tooth bleaching material was obtained.

Comparative Example 3
Mazerustar kk-400 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 400 mL plastic container filled with 97.4 g of purified water and 0.7 g of titanium oxide was set in a Mazerustar, and stirred and mixed at a revolution of 540 rpm and a rotation of 238 rpm for 3 minutes (step (1)). Next, the plastic container was taken out and 5.8 g of carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added. Then, the plastic container was set in the Mazerustar again and stirred for 30 minutes at revolution 540 rpm and rotation 238 rpm. Mixed (step (2)). Subsequently, the plastic container was taken out again, 77.4 g of glycerin and 19.0 g of a 23.3% sodium hydroxide aqueous solution were added, and then the plastic container was set again on the Mazerustar and stirred and mixed for 267 minutes at revolution 540 rpm and rotation 238 rpm. (Step (3): pH 12 of the thickening solution). A thickening solution for tooth bleaching material was obtained which was in the form of a white cream with viscosity but with a visible splint remaining.

Comparative Example 4
Mazerustar kk-400 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 400 mL plastic container filled with 77.4 g of glycerin and 0.7 g of titanium oxide was set on a Mazerustar, and stirred and mixed for 3 minutes at revolution 540 rpm and rotation 238 rpm (step (1)). Next, the plastic container was taken out and 5.8 g of carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was added. Then, the plastic container was set in the Mazerustar again and stirred for 30 minutes at revolution 540 rpm and rotation 238 rpm. Mixed (step (2)). The solution obtained at this stage had a very high viscosity and almost no fluidity. Further, many undissolved materials of Hibiswako 105 were observed. Subsequently, the plastic container was taken out again, and 116.5 g of a 3.8% aqueous sodium hydroxide solution was added. Then, the plastic container was set in the Mazerustar again, and stirred and mixed at revolution 540 rpm and rotation 238 rpm for 267 minutes (step (3)). : PH of thickening liquid 12). A thick white cream with a viscosity was obtained, but a large number of visible powders remained, and a part of the powder was transparent to obtain a thickening solution for a tooth bleaching material.

Comparative Example 5
Mazerustar kk-400 (manufactured by Kurabo Industries Co., Ltd.) was used as a planetary stirring device, glycerin 77.4 g, titanium oxide 0.7 g, carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries)) 5.8 g, 3 A 400 mL plastic container filled with 116.4 g of an 8% sodium hydroxide aqueous solution was set in a Mazerustar and stirred and mixed (pH 11 of the thickening solution) for 330 minutes at revolution 540 rpm and rotation 238 rpm to obtain a dental bleaching material containing titanium oxide. . A thick white cream-like thickener for tooth bleaching material was obtained.

Comparative Example 6
Mazerustar kk-400 (made by Kurabo Industries) was used as a planetary stirring apparatus. A 400 mL plastic container filled with 77.4 g of glycerin, 12.0 g of purified water, 0.7 g of titanium oxide, and 5.8 g of carboxyvinyl polymer (Hibis Wako 105 (manufactured by Wako Pure Chemical Industries, Ltd.)) was set in Mazerustar, and revolution 540 rpm The mixture was stirred and mixed at 238 rpm for 33 minutes. Next, the plastic container was taken out, 104.4 g of 4.2% sodium hydroxide aqueous solution was added, and then the plastic container was set again on the Mazerustar, and stirred and mixed for 200 minutes at revolution 540 rpm and rotation 238 rpm (pH 11 of the thickening solution). . A white cream-like thickening solution for tooth bleaching material in which a visible step was left was obtained.

  The following evaluation was performed in order to confirm the titanium oxide dispersibility, the viscosity, and the amount of spatter generation of the thickening solutions for tooth bleaching materials obtained in Examples 1 to 5 and Comparative Examples 1 to 6.

<Titanium oxide dispersibility>
The dispersibility of titanium oxide was examined by the following procedure using a digital microscope VHX-500 manufactured by Keyence Corporation.
(1) A thickening solution for tooth bleaching material was placed on a glass plate, and a cover glass was set to obtain an observation sample.
(2) After setting on the observation table of the microscope, select the titanium oxide particles with the largest particle size among the titanium oxide particles in the field of view, and extract 10 particles in descending order of particle size based on this. Was measured.
(3) The average particle size was calculated using the 10 data extracted and measured above.

<Viscosity>
The viscosity was measured using a cone plate viscometer (Programmable Viscometer DV-II + Pro manufactured by Brookfield) according to the following procedure. The measurement was performed 3 times, and the average value was obtained.
(1) Bleaching material A 0.5 mL viscometer was set at the measurement site, and the measurement site was set to 25 ° C.
(2) The value after 3 minutes was read at a rotation speed of 1.5 rpm.

<Observed amount of spatter and observation of undissolved thickener>
In order to observe the dissolved state of the added organic thickener, observation of the amount of spatter generated and observation of the undissolved thickener were performed according to the following procedure.
a) Observation of generation amount of spattered powder 200 g of the manufactured thickening solution for tooth bleaching material was passed through a test sieve having a nominal size (opening) of 1 mm. After passing through the whole liquid, the number of splints remaining on the sieve net was confirmed. When the number of remaining pollens was 0, it was determined as ○, and 1 or more as ×.
b) Observation of undissolved material of thickener 200 g of the prepared thickening solution for tooth bleaching material was poured into a SUS bat and the thickness was increased to about 5 mm. The presence or absence of the thickener undissolved material was observed.

Example 6
1.14 g thickening solution for tooth bleaching material produced in Example 1 and an aqueous solution containing hydrogen peroxide (7.3% hydrogen peroxide, 1.1% phosphoric acid, 4.2% pyrophosphoric acid 4Na · 10 water) 1.06 g (Japanese product, the balance is water) was placed in a glass jar and mixed well with a resin shell to obtain a uniform solution. In order to examine the bleaching effect of the bleaching material containing 3.5% hydrogen peroxide that became uniform, the following model bleaching test using hematoporphyrin-dyed paper was performed.

<Hematoporphyrin model bleaching test>
The hematoporphyrin model bleach test was carried out by the following procedure.
(1) Glossy paper was dyed with a hematoporphyrin solution.
(2) L * (lightness), a * (redness), and b * (yellowness) values were selected to be close to 52, 23, and 24, respectively.
(3) A bleaching material was applied to this dyed paper.
(4) Bleaching test was performed by irradiating with light according to the following procedure.
a) Using a dental visible light irradiator (trade name: Optilux 501 manufactured by Demetron), the coated surface was irradiated with light at an irradiation distance of 5 mm.
b) L *, a *, and b * of the dyed paper with a total light irradiation time of 2 minutes were measured with a spectral color difference meter (SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.).
c) Differences (Δ) in L *, a *, and b * values between the total light irradiation time of 2 minutes and before the test were calculated as ΔL *, Δa *, and Δb *, respectively.

Reference example 1
A hematoporphyrin model bleaching test was conducted in the same procedure as in Example 6 using a commercially available pirene (Mitsubishi Gas Chemical Co., Ltd.) as a tooth bleaching material containing 3.5% hydrogen peroxide.

  Test results in Example 6 and Reference Example 1 are shown in Table 2. The results of Example 6 showed a bleaching effect equivalent to or higher than that of the commercially available pyrene implemented in Reference Example 1.

ΔＬ＊＝試験後Ｌ＊−試験前Ｌ＊（数値 大 ： 明度上昇）
Δａ＊＝試験後ａ＊−試験前ａ＊（数値 小 ： 赤味減少）
Δｂ＊＝試験後ｂ＊−試験前ｂ＊（数値 小 ： 黄色味減少）

ΔL * = L * after test-L * before test (large numerical value: increased brightness)
Δa * = after test a * −before test a * (small value: redness reduction)
Δb * = b * after test−b * before test (numerical value small: yellowish decrease)

Claims (6)

A method for producing a thickening liquid for tooth bleaching material comprising titanium oxide having a photocatalytic action and an organic thickener, comprising the following steps (1) to (3): Production method.
(1): Step of mixing titanium oxide with an aqueous solution containing 65 to 90% by mass of polyhydric alcohol (2): Mixed aqueous solution containing polyhydric alcohol and titanium oxide obtained in step (1), and organic thickener Step (3) of mixing the step: Adjusting the pH of the thickened liquid obtained in Step (2) to 5 to 12   The production method according to claim 1, wherein the polyhydric alcohol is at least one selected from the group consisting of glycerin, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, sorbitol and mannitol.   The method according to claim 1 or 2, wherein the organic thickener is at least one selected from sodium carboxymethylcellulose, carboxymethylcellulose calcium and polyacrylic acid or salts thereof, and carboxyvinyl polymer.   The manufacturing method in any one of Claims 1-3 which add the aqueous solution containing a basic compound in a process (3).   The basic compound is selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, 4 sodium pyrophosphate, 4 potassium pyrophosphate, sodium polyphosphates, potassium polyphosphates, trisodium phosphate and tripotassium phosphate. The production method according to claim 4, which is at least one selected. A tooth bleaching material comprising a thickening solution for tooth bleaching material produced by the method according to claim 1 and an aqueous solution containing hydrogen peroxide and / or a compound that generates hydrogen peroxide.