JPH058686B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a dentifrice composition that has excellent stability over time, and in particular, when prepared to be transparent, maintains its transparency even after long-term storage. BACKGROUND ART Conventionally, various silica-based abrasives have been proposed as abrasives for preparing transparent toothpastes.
However, conventionally used silica-based abrasives have poor stability over time, and even if a transparent toothpaste is prepared by mixing this silica-based abrasive with a transparent vehicle having substantially the same refractive index, it will last for a long time. When stored for a period of time, there is a problem that the refractive index of the silica-based abrasive changes in the toothpaste system, resulting in the inconvenience that the refractive index of the silica-based abrasive and the transparent vehicle no longer match, resulting in a decrease in transparency. arise. In addition, the conventionally used silica-based abrasives are
It usually has a high refractive index of about 1.46, and when using it to prepare transparent toothpaste, the transparent vehicle must also be prepared to have the same high refractive index of about 1.46. The amount of water inside must be reduced and the amount of high refractive index components such as glycerin and sorbitol must be increased. However, adding a large amount of glycerin, sorbitol, etc. increases the production cost of transparent toothpaste and may give it an excessively sweet taste.Additionally, adding too much glycerin may heat up the oral cavity due to the heat of dissolution. This reduces the feeling of use, as it may give a harsh feel. Furthermore, if the amount of glycerin, sorbitol, etc. is large, problems will arise in usability, such as poor kneading and stringiness when the toothpaste is extruded from the tube. Summary of the Invention In view of the above circumstances, the present inventors have conducted intensive research into an abrasive that has excellent stability over time in a dentifrice composition and maintains transparency for a long period of time even when the dentifrice composition is prepared transparent. As a result, the specific surface area (hereinafter referred to as "specific surface area by N ₂ adsorption") measured by the BET method using the nitrogen adsorption method was 5 to 5.
100 m ² /g and a specific surface area (hereinafter referred to as "specific surface area by water vapor adsorption") measured by the BET method using a water vapor adsorption method of 100 to 400 m ² /g is used as a toothpaste composition. It was found that the refractive index is stable in the medium, its refractive index is difficult to change, and it has excellent stability over time. That is, when preparing transparent toothpaste, silica-based abrasives with various specific surface areas (specific surface areas due to N ₂ adsorption) have been used in the past. Silica-based abrasives have approximately the same specific surface area due to N ₂ adsorption and water vapor adsorption (usually,
The ratio of the specific surface area due to water vapor adsorption to the specific surface area due to _N2 adsorption is 0.5 to 2.0), and as mentioned above, this type of silica-based abrasive has poor stability over time, and its refractive index changes in the toothpaste composition. It was hot. However, the specific surface area due to N ₂ adsorption is 5 to 100
m ² /g, and the specific surface area due to water vapor adsorption is 100
~400 m ² /g, and thus has a much larger specific surface area due to water vapor adsorption than that due to N ₂ adsorption, preferably an amorphous abrasive silica with a specific surface area due to water vapor adsorption relative to the specific surface area due to N ₂ adsorption. It has been found that when silica having a ratio of 2 to 30 is used, the stability over time is excellent, and there is almost no change in the refractive index even after long-term storage in a dentifrice composition. Furthermore, among these silicas, the pore volume measured by nitrogen adsorption method (pore volume by _N2 adsorption)
is 0.01 to 0.15ml/g, and the pore volume measured by water vapor adsorption method (pore volume by water vapor adsorption) is
It has been found that 0.2-0.7 ml/g of silica is more effective. Also, these silicas are 1.420
Silica can be prepared to have a low refractive index of ~1.450, but when preparing transparent toothpaste using silica with such a low refractive index, the refractive index of the transparent vehicle can also be lowered, so glycerin, sorbitol, etc. Since the amount of high refractive index components can be lowered and the amount of water can be increased, the cost, usability, and
To obtain at a low cost a transparent toothpaste which can solve the problem of usability, maintains transparency well because the refractive index of silica is hard to change even after long-term storage, and has good feel and usability. The inventors have discovered that this can be done, and have come up with the present invention. The present invention will be explained in more detail below. Structure of the Invention The dentifrice composition according to the present invention uses N ₂ as an abrasive.
Amorphous abrasive silica having a specific surface area of 5 to 100 m ² /g due to adsorption and a specific surface area of 100 to 400 m ² /g due to water vapor adsorption is used,
By using this type of silica, it is possible to obtain a dentifrice composition that has excellent stability over time and shows almost no deterioration in quality even after long-term storage. In this case, this amorphous abrasive silica can be produced by various methods, but it is particularly preferable to use hydrated synthetic silica.
Amorphous hydrated synthetic silica having the above specific surface area has very high stability over time. The silica used in the present invention has a specific surface area as described above, and in this case, the specific surface area due to N ₂ adsorption is 5 to 50 m ² /g, and the specific surface area due to water vapor adsorption is 150 to 300 m ² /g. It is more preferable that the ratio of the specific surface area due to water vapor adsorption to the specific surface area due to N ₂ adsorption is 2 to 30, especially 3 to 20, and the pore volume due to N ₂ adsorption is more preferable.
0.01-0.15ml/g, especially 0.02-0.1ml/g,
Silica having a pore volume by water vapor adsorption of 0.2 to 0.7 ml/g, particularly 0.3 to 0.6 ml/g is more preferable, and by using this type of silica, the objects of the present invention can be better achieved. The silica used in the present invention preferably has a liquid absorption of 0.4 to 2.0 ml/g, particularly 0.6 to 1.5 ml/g, and has a specific gravity of 1.9 to 2.3. Furthermore, when preparing a transparent toothpaste, the refractive index of the silica used in the present invention is preferably 1.420 to 1.450, particularly 1.430 to 1.445, and by using silica with such a low refractive index, A transparent vehicle can be prepared with a low refractive index by reducing the amount of glycerin, sorbitol, etc. Incidentally, such low refractive index silica having a refractive index of 1.420 to 1.450 is achieved when the specific surface area by N ₂ adsorption and the specific surface area by water vapor adsorption are adjusted to the above ranges. Silica with a low refractive index can be easily obtained. On the other hand, the refractive index of conventionally used silica-based abrasives, where there is almost no difference between the specific surface area due to N ₂ adsorption and the specific surface area due to water vapor adsorption, is usually about 1.45 to 1.47, is difficult to prepare. Here, the amorphous abrasive silica used in the present invention has a SiO ₂ content of 70% or more (weight%, the same applies hereinafter),
Particularly preferred is 85% or more. Furthermore, the silica used in the present invention may be one in which aluminum or zirconium is bonded to SiO ₂ (so-called aluminosilicate or zirconosilicate). In this case, the bonding amount of aluminum or zirconium is preferably 10% or less, particularly 2% or less, based on SiO ₂ . Furthermore, the silica used in the present invention may have metals such as sodium, potassium, lithium, calcium, magnesium, and hafnium, which are usually mixed in during silica production, combined or dispersed, but the amount thereof is in proportion to SiO _{2 .} It is preferably 10% or less, particularly 5% or less. Furthermore, the amount of moisture attached is less than 20% at 25℃ and 70%RH, especially at 15%.
% or less, and the ignition loss is preferably 15% or less, particularly 10% or less. The present invention uses the above-mentioned amorphous abrasive silica as an abrasive, but in this case, the particle size is
The average particle size measured by SEM method is 0.01~1μm, especially
0.05~0.5μm, average particle size measured by sedimentation method is 1~
It is preferably 30 μm, especially 1 to 15 μm. Further, the polishing power is preferably 1 to 50 mg, particularly 1 to 20 mg, as measured by a copper plate polishing method.
Note that the polishing power of the silica used in the present invention can be easily adjusted to a desired value by selecting various specific surface areas, especially due to its N ₂ adsorption (N ₂
The polishing power tends to decrease as the specific surface area due to adsorption increases). The amount of the above-mentioned amorphous abrasive silica in the toothpaste composition varies depending on its type, purpose of use, etc., and is not necessarily limited, but is usually 1 to 50% of the total composition.
%, especially from 5 to 35%. In addition to the amorphous abrasive silica, the dentifrice composition of the present invention may optionally contain other abrasives, such as secondary
Calcium phosphate, calcium carbonate, calcium pyrophosphate, insoluble sodium metaphosphate, other silica-based abrasives, aluminum oxide, aluminum hydroxide, titanium dioxide, resin, etc. can also be blended, but in order to exhibit the characteristics of the silica of the present invention, Its content should be less than 20% of the total composition, especially
It is preferably 10% or less, and especially when producing transparent toothpaste, it is preferably 20% or less, particularly 10% or less, based on the weight of the silica of the present invention. Note that in the present invention, transparent toothpaste includes not only completely transparent toothpaste but also semi-transparent toothpaste. The dentifrice compositions of the present invention may be made by blending the abrasives described above with a dentifrice vehicle. In this case, components commonly used in toothpaste vehicles are used, such as sodium carboxymethyl cellulose, hydroxyethyl cellulose, alginate, carrageenan, gum arabic,
Binder such as polyvinyl alcohol, thickening agent such as polyethylene glycol, sorbitol, glycerin, propylene glycol, sodium lauryl sulfate, sodium dodecylbenzenesulfonate,
Hydrogenated Coconut Fatty Acid Monoglyceride Sodium Monosulfate, Sodium Lauryl Sulfoacetate,
Surfactants such as sodium N-lauroyl sarcosinate, N-acylglutamate, lauric acid diethanolamide, sucrose fatty acid ester, and essential oils such as peppermint and spearmint, l-
Flavoring materials such as menthol, carvone, eugenol, anethole, etc., saccharin sodium, stevioside, neohesperidyl dihydrochalcone, glycyrrhizin, perillartin, p-
Sweeteners such as methoxycinnamic aldehyde,
Pigments, preservatives, dextranase, mutanase, sorbic acid, alexidine, β-glycyrrhetinic acid, hinokitiol, chlorhexidine,
Alkylglycine, alkyldiaminoethylglycine salt, allantoin, ε-aminocaproic acid,
Tranexamic acid, azulene, vitamin E, water-soluble primary or secondary phosphates, quaternary ammonium compounds such as cetylpyridinium chloride, sodium chloride, crude drug extracts, sodium monofluorophosphate, sodium fluoride, difluoride A dentifrice vehicle can be prepared by appropriately selecting active ingredients such as tin, etc., and mixing them with water. In addition,
The silica of the present invention hardly adsorbs fluoride, and fluoride is stably retained in the dentifrice composition, so that fluoride can be effectively incorporated therein. A transparent dentifrice can be prepared by making the dentifrice vehicle described above transparent and having its refractive index substantially match the refractive index of the silica of the present invention. In this case, if a low refractive index silica with a refractive index of 1.420 to 1.450 is used, the refractive index of the transparent toothpaste vehicle can be adjusted to a low refractive index accordingly. The amount of water can be increased while reducing the content of ingredients. For this reason, when a large amount of glycerin or sorbitol is added, the feeling of use is poor, and when extruded from the tube, it is difficult to mix.
Problems in usability such as stringiness can be improved, and a transparent toothpaste with excellent feel and usability can be obtained. Moreover, since the amount of water can be increased as described above, manufacturing costs can also be reduced. In addition, when toothpaste is manufactured according to the present invention,
Although the PH is not necessarily limited, it is preferably PH5-9. Effects of the Invention The dentifrice composition of the present invention has a specific surface area of 5 to 100 m ² /g by BET method measured by nitrogen adsorption method, and a specific surface area of 100 to 400 m ² /g by BET method measured by water vapor adsorption method. It is characterized by using amorphous abrasive silica (g) as an abrasive, has excellent stability over time, and maintains its transparency for a long period of time even when it is prepared to be transparent. Hereinafter, the present invention will be specifically illustrated by examples. [Examples 1 and 2, Comparative Examples 1 and 2] A transparent toothpaste having the formulation shown in Table 3 was prepared using the synthetic amorphous precipitated silica shown in Tables 1 and 2 as an abrasive.

【table】

【table】

【table】

[Table] In Tables 1 and 2, the physical properties of silica were measured by the following method. N ₂ adsorption Measure the nitrogen adsorption isotherm at liquid nitrogen temperature (-196°C). The sample is degassed at 105° C. for 5 hours or more at a vacuum level of 1×10 ^-4 mmHg or higher. (1) Specific surface area Using the above adsorption isotherm, calculate the surface area per gram of anhydride by the BET method. However, the molecular cross-sectional area of nitrogen was set to 16.2 Å ² . (2) Pore volume Using the above adsorption isotherm, the amount of adsorption at a relative pressure of 0.967 (corresponding to a pore diameter of 600 Å) is defined as the pore volume. Here, the relative pressure is the ratio of the vapor pressure at the time of measurement to the saturated vapor pressure. Water vapor adsorption Measure the water vapor adsorption isotherm at 25℃ using the desiccator method. The sample should be dried at 105°C for 5 hours or more. (1) Specific surface area Using the above adsorption isotherm, calculate the surface area per gram of anhydride by the BET method. However, the molecular cross-sectional area of water molecules was set to 12.5 Å ² . (2) Pore volume Using the above adsorption isotherm, the amount of adsorption at a relative pressure of 1.00 (saturated vapor pressure) is defined as the pore volume. Refractive Index Glycerin and water are appropriately mixed to prepare dispersion media having various refractive indices. Sample in 35g of each dispersion medium
15 g was dispersed and mixed for 10 minutes using a vacuum stirrer and crusher for defoaming. The refractive index and turbidity of this mixture at 25°C are measured, a refractive index-turbidity curve is drawn, and the refractive index of the mixture with the minimum turbidity is taken as the refractive index of the sample. In this case, an Atsube refractometer was used to measure the refractive index, and an integrating sphere turbidity meter was used to measure the turbidity, and the turbidity was determined from the transmittance at a sample thickness of 1 mm. Amount of liquid absorbed: Dry the sample at 105℃ for 2 hours to remove adhering water and make it anhydrous.Weigh 1.0g, place it on a glass plate, and add 42.5% glycerin aqueous solution in small amounts using 5ml microbiules. While adding, mix evenly with a stainless steel spatula to distribute the liquid evenly. The end point is when the sample becomes granular, then becomes a hard putty-like lump, and the mixture of sample and glycerin does not stick to the glass plate. shall be. Specific gravity (1) Testing of pycnometer bottle After cleaning and drying the 25ml pycnometer bottle (105℃),
Measure its weight (W _P ). Fill a pycnometer with boiled and cooled distilled water, leave it in the balance chamber, stopper it, and add 0.1 mg.
Accurately measure its weight (W _L ) up to the point. Immediately after weighing, insert a thermometer into the pycnometer and measure the water temperature (Ta). The volume of the specific gravity bottle (V ₄ ) at 4° C. is determined by the following formula. V ₄ (ml) = (W _L − W _P )・δa/1+α(Ta−4) δa: Specific volume of water at Ta℃ α: Body expansion coefficient of glass (0.000033) (2) Measurement of specific gravity Sample <Measure free moisture (mf%) separately. ＞
Place approximately 1.0 g into a specific gravity bottle and measure its weight ( _WS ). Add distilled water to a depth of approximately 0.5 cm from the surface of the sample, repeat depressurization and normal pressure several times under vacuum, then fill with distilled water and leave in the balance chamber until the water becomes clear. Close the stopper and measure its weight (W _S+L ) and temperature (Tb). Find the specific gravity using the following formula. The dry weight (W) of the sample is W (g) = W _S - W _P /1 + 0.01 × mf (%) Tb The volume of the pycnometer at °C (Vb is) Vb (ml) = V ₄ {1 + α ( Tb-4)} The specific gravity (S) of the sample is (where δb is the specific volume of water at Tb℃) S=W/Vb-(W _S+L −W _P −W)・δb Average particle size Scanning The average particle diameter (mode diameter) is measured by electron microscopy observation. Polishing power (copper plate polishing method) Using a brushing type polishing machine (inclined type), a copper plate with a smooth surface was immersed in a solution in which 15 g of the sample was dispersed in 70 g of a 60% glycerin aqueous solution (containing 0.4% sodium carboxymethyl cellulose), and a load of 500 was applied.
After polishing the copper plate 20,000 times under a certain amount of g, the weight loss of the copper plate is measured, and this is taken as the polishing force. Next, the storage stability, usability, and stringiness of the transparent toothpastes having the formulations shown in Table 3 were evaluated by the following methods. The results are shown in Tables 4 and 5.

[Table] Note: Turbidity is measured using an integrating sphere turbidity meter, and the sample thickness is 1.
It is in mm.

[Table] Examples 3 to 12 are shown next, and Table 6 shows the properties of the synthetic amorphous precipitated silica used in the following examples.

[Table] [Example 3] Silica E 5.0% Thickening silica 3.0 Polyethylene glycol 400 4.0 96% glycerin 20.5 70% sorbitol 45.3 Sodium carboxymethyl cellulose 1.5 Tocophenol acetate 0.05 Sodium lauryl sulfate 1.1 Sodium saccharin 0.1 Fragrance 1.0 Purified water Total remaining 100.0% [Example 4] Silica E 10.0% Thickening silica 3.0 Polyethylene glycol 400 4.0 70% sorbitol 65.0 Sodium carboxymethyl cellulose 1.2 Tranexamic acid 0.05 Sodium lauryl sulfate 1.2 Sodium saccharin 0.1 Fragrance 1.0 Purified water Total balance 100.0% [Example 5 ] Silica E 15.0% Thickening silica 2.5 Polyethylene glycol 400 4.0 96% glycerin 12.0 70% sorbitol 46.2 Sodium carboxymethylcellulose 1.1 ε-Aminocaproic acid 0.01 β-Glycyrrhetinic acid 0.01 Sodium lauryl sulfate 1.2 Sodium saccharin 0.1 Flavor 1.0 Purified water Remaining Total 100.0 % [Example 6] Silica E 20.0% Thickening silica 2.0 Polyethylene glycol 400 4.0 70% sorbitol 62.5 Sodium carboxymethylcellulose 1.1 Dipotassium glycyrrhizinate 0.01 Dextranase 2000u/g Sodium lauryl sulfate 1.5 Sodium saccharin 0.1 Fragrance 1.0 Purified water Total remaining 100.0% [Example 7] Silica F 9.0% Thickening silica 3.0 Polyethylene glycol 400 5.0 70% Sorbit 65.2 Sodium carboxymethyl cellulose 1.2 Sodium monofluorophosphate 0.76 Sodium lauryl sulfate 1.2 Sodium saccharin 0.1 Flavor 1.0 Purified water Total balance 100.0% [Example 8] Silica F 18.0% Thickening silica 2.0 Polyethylene glycol 400 5.0 96% glycerin 18.9 70% sorbitol 43.0 Sodium carboxymethyl cellulose 1.1 Chlorhexidine gluconate 0.01 Sodium lauryl sulfate 1.2 Sodium saccharin 0.1 Fragrance 1.0 Purified water Remaining total 100.0% [Example 9 ] Silica F 32.0% Thickening silica 2.0 Polyethylene glycol 400 5.0 96% glycerin 9.8 70% sorbitol 38.5 Sodium carboxymethylcellulose 1.1 Sodium monofluorophosphate 0.76 Sodium lauryl sulfate 1.2 Sodium saccharin 0.1 Fragrance 1.0 Purified water Total balance 100.0% [Example 10] Silica G 15.0% Thickening silica 2.5 Polyethylene glycol 400 4.0 96% glycerin 10.5 70% sorbitol 43.0 Sodium carboxymethyl cellulose 1.2 Sodium fluoride 0.2 Sodium lauryl sulfate 1.5 Sodium saccharin 0.1 Fragrance 1.0 Purified water Total balance 100.0% [Example 11] Rika G 20.0% Thickening Silica 2.0 Polyethylene Glycol 400 4.0 70% Sorbit 63.8 Sodium Carboxymethyl Cellulose 1.2 Stannous Fluoride 0.4 Sodium Lauryl Sulfate 1.5 Sodium Satucharin 0.1 Flavor 1.0 Purified Water Remaining Total 100.0% [Example 12] Silica G 25.0% Thickening silica 2.0 Polyethylene glycol 400 4.0 96% glycerin 5.0 70% sorbitol 45.0 Xanthan gum 0.6 Sodium monofluorophosphate 0.76 Sodium lauryl sulfate 1.5 Sodium saccharin 0.1 Fragrance 1.0 Purified water Remaining total 100.0% All of the compositions of Examples 3 to 12 The active ingredients were stably blended.

Claims (1)

[Scope of Claims] 1. Specific surface area measured by BET method using nitrogen adsorption method is 5 to 100 m ² /g, and specific surface area measured by BET method using water vapor adsorption method is 100 to 100 m 2 /g.
A dentifrice composition characterized in that amorphous abrasive silica having an amount of 400 m ² /g is used as an abrasive. 2 Specific surface area measured by BET method measured by nitrogen adsorption method vs. specific surface area measured by water vapor adsorption method
The dentifrice composition according to claim 1, which uses amorphous abrasive silica having a specific surface area ratio of 2 to 30 as determined by BET method. 3 Pore volume measured by nitrogen adsorption method is 0.01~
Claim 1 or 2 uses amorphous abrasive silica having a pore volume of 0.15 ml/g and a pore volume of 0.2 to 0.7 ml/g measured by water vapor adsorption
The dentifrice composition described in Section 1. 4. A toothpaste vehicle mixed with amorphous abrasive silica is prepared to be transparent, and its refractive index is adjusted to be substantially the same as the refractive index of the silica, thereby making it transparent. The dentifrice composition according to any one of items 1 to 3. 5 The refractive index of amorphous abrasive silica is 1.420 to 1.450
The dentifrice composition according to claim 4.