JPS6348580B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is characterized in that the core substance is formed of a colored oily substance, and the insoluble salt is at least partially buried in the microcapsule membrane itself. Regarding a toothpaste composition containing as an indicator opaque microcapsules that are precipitated to cover a microcapsule membrane and hide the color of a colored oily substance, more specifically, the microcapsules are destroyed during use and the core substance flows out. This invention relates to an indicator-containing dentifrice composition in which the end point of brushing is clearly perceived by coloring the dentifrice composition in the color of this core substance (colored oily substance).

[Problems to be solved by the prior art and the invention] Generally, it is considered appropriate to brush teeth for 3 to 5 minutes, but when brushing using a normal toothpaste composition, Since the end point is not clear, insufficient brushing often occurs.

In order to solve these problems, the present inventors considered adding an indicator to the toothpaste composition to clarify the end point of brushing, and in particular microencapsulated a colored oily substance and used it as an indicator. I considered doing so.

However, since microcapsule membranes are generally made of a thin, semi-transparent material, when the core material is colored, the color tone is weakened, but still.
The color of the core substance appears on the exterior. For this reason, if the microcapsule is colored from the beginning, it cannot function as an indicator even if it is added directly to the toothpaste composition, so it is necessary to use opaque microcapsules in which the color of the core substance does not appear on the outside. be.

Conventionally, a common method for making microcapsules opaque is to physically coat the surface of the microcapsules with a white pigment or a white inorganic salt. For example, there is a method in which an inorganic salt is attached to a nylon capsule using electrostatic charge generated by friction ("Microcapsule" by Tamotsu Kondo et al., pp. 79-81, Sankyo Publishing). but,
Opaque microcapsules produced by this method can relatively stably attach and retain white pigments etc. in a non-aqueous system, but when present in an aqueous system, pigments and white inorganic salts easily escape from the surface of the microcapsules. It has the disadvantage that the opacity decreases due to shedding and the coloration of the core substance reappears.

The present invention was created in view of the above circumstances, and by incorporating microcapsules that remain stable and opaque even when blended into toothpaste compositions and have excellent functions as indicators, it is possible to clearly determine the end point of brushing. The purpose of the present invention is to provide a dentifrice composition that has the following properties.

[Means and actions for solving problems]

In order to achieve the above object, the present inventors conducted intensive studies and found that the core material was formed from a colored oily substance, and the microcapsules having the required anions or cations in the membrane were coated with these anions or cations. Insoluble salts (salts that are insoluble or poorly soluble in water, By precipitating opaque microcapsules (the same applies hereinafter), opaque microcapsules maintain stable opacity even when used in aqueous as well as non-aqueous systems, reliably hide the color of the core substance made of colored oily substances, and furthermore have a high film strength. It has been found that the opaque microcapsules obtained can be produced without using any complicated method, and that the resulting opaque microcapsules can be incorporated into dentifrice compositions and used effectively as an indicator to notify the end point of dentifrice.

That is, when conventional translucent microcapsules are used as indicators in toothpaste compositions,
If a slight discoloration phenomenon is already observed in the dentifrice composition before its use, and if the insoluble salt simply adheres to the microcapsule membrane, the insoluble salt will be desorbed in the dentifrice composition and the discoloration phenomenon will also occur. However, when the opaque microcapsules of the present invention were used, no discoloration was observed, and the film was destroyed by brushing in the oral cavity for a certain period of time, and the dentifrice composition did not show any discoloration for the first time. It was discovered that this method has a special effect of giving a change in color tone and signaling the end of brushing, which led to the creation of the present invention.

Therefore, in the present invention, the core substance is formed of a colored oily substance, and the insoluble salt is precipitated so as to cover the microcapsule membrane while being at least partially buried in the microcapsule membrane itself. To provide a dentifrice composition containing opaque microcapsules in which the color of the colored oily substance is hidden.

The present invention will be explained in more detail below.

In the opaque microcapsules used as indicators in the present invention, the microcapsules themselves can be manufactured by a conventional method such as a simple core cellvation method, a complex core cellvation method, or other common methods. In the invention, since a colored hydrophobic and lipophilic substance is used as a core material, microencapsulation by a complex coacervation method is generally employed.

That is, in this complex coacervation method, a core material is first dispersed in either a hydrophilic cation colloid aqueous solution or a hydrophilic anion colloid aqueous solution, and then the other of the above hydrophilic colloid aqueous solutions is mixed. Microcapsules are produced by reducing the pH to 4.5 or less. In this case, gelatin, casein, albumin, fibrinogen, hemoglobin, soluble collagen peptide, etc. are used as hydrophilic cation colloid substances, and hydrophilic anion colloid substances are used. Generally, gum arabic, sodium alginate, carboxymethylcellulose, agar, etc. can be used. Also, the use of an activator when dispersing the core material facilitates dispersion. Furthermore, microcapsule hardening agents can also be used.
For example, hardening agents such as formalin, glutaraldehyde, chromium alum, iron alum, potassium alum, tannic acid, gallic acid, and the like are commonly used.

In addition, as a method for manufacturing microcapsules,
As mentioned above, for example, a simple coacervation method in which microcapsules are formed by adding sodium sulfate or ethanol to an aqueous gelatin solution at the isoelectric point can also be employed.

The microcapsules used in the present invention can be manufactured by the method described above, but in this case, a colored oily substance is used as the core material of the microcapsules. Colored oily substances include corn, rapeseed, soybeans, cottonseed, rice bran, safflower,
Coloring is done by adding annatto, β-carotene, paprika, and other oil-based pigments to vegetable liquid oils such as sesame and olive, solid fats with a melting point of 40℃ or less such as lard, head, and coconut oil, and oily substances such as silicone oil. It is preferable to use a colored oily substance.

Therefore, in the present invention, an insoluble salt is precipitated in the microcapsule membrane itself obtained as described above, and the microcapsules are made opaque and are blended as an indicator, thereby separating the colored oily substance from the above-mentioned colored oily substance. The color of the core substance is hidden, and when the dentifrice composition is used, the microcapsules are destroyed by brushing, and the core substance (colored oily substance) flows out. The composition is colored in this color.

In this case, the method for precipitating insoluble salts is to permeate microcapsules in which a compound having anions or cations is impregnated into the membrane with cations or anions that react with the anions or cations to produce insoluble salts. This method is adopted depending on the situation.

Here, as a method for obtaining microcapsules impregnated with a compound having a desired anion or cation in the membrane, the obtained microcapsules are dispersed in a solution of a compound containing the desired anion or cation. It is also possible to adopt a method in which cations or anions are impregnated into the membrane of microcapsules, but a compound having these anions or cations is added during the microcapsule manufacturing process, and when the microcapsules are produced, the membrane is It is preferable to impregnate the required anions or cations therein in order to simplify the process.

In addition, as a method of infiltrating the microcapsule membrane impregnated with the desired anions or cations with cations or anions that react with these anions or cations to produce insoluble salts, the microcapsules are A method such as dispersion in a compound solution containing ions is adopted.

In the present invention, the anions or cations are not particularly limited, but phosphate ions, sulfate ions, carbonate ions, etc. are usually used as anions, and calcium ions, barium ions, etc. are used as cations. Carbon dioxide gas can also be used as a compound using anions.

To explain this insoluble salt precipitation method in more detail,
For example, if the complex coacervation method described above is employed, the acid used for pH adjustment is an acid containing the desired anion, such as sulfuric acid,
Phosphoric acid, carbonic acid, etc. are used, and an acid for pH adjustment is simultaneously used as a source of the required anions, and these anions are impregnated into the membrane at the same time as the microcapsules are produced. Alternatively, various water-soluble compounds having the desired anion, such as sodium sulfate, sodium carbonate, sodium phosphate, etc., can be added in advance at other appropriate stages during the dispersion of the core material. When adjusting the pH when using a capsule curing agent,
It is possible to use compounds containing these anions, and by adding compounds containing the desired anions, it is possible to simultaneously produce microcapsules and impregnate the desired anions into the membrane. This is convenient because the process can be simplified.

Next, the microcapsules are separated from the microcapsule dispersion thus obtained using, for example, a centrifugal separator. Since the membrane of the separated microcapsules is impregnated with the anion, it is treated with an aqueous solution of a compound containing a cation, such as barium chloride or calcium chloride, which reacts with the anion to produce an insoluble salt. When added to an aqueous solution of barium salt, calcium salt, etc. and stirred, the cations penetrate into the membrane of the microcapsule itself and react with the anions in the membrane, causing precipitation of insoluble salts within the microcapsule membrane itself. is precipitated to produce opaque microcapsules. In this case, stirring is usually sufficient for about 10 minutes to 2 hours, and by adjusting the stirring speed, it is possible to control the particle size of the precipitate formed on the microcapsule membrane. In other words, stirring speed and particle size are inversely proportional.

The method for manufacturing opaque microcapsules described above involves the use of an acid containing the desired anion when producing microcapsules by the complex coacervation method. Capsules are generated and a compound containing the desired cation is applied to the capsule, but the compound containing the desired cation is added at an appropriate stage during the microcapsule production process, and at the same time as the microcapsule is generated. The microcapsules may be rendered opaque by impregnating the microcapsule membrane with cations and dispersing them in an aqueous solution containing anions to precipitate insoluble salts within the microcapsule membrane itself.

In addition, for microcapsules obtained by the complex coacervation method, or microcapsules obtained by the simple coacervation method or other methods (the membrane is not impregnated with the required anions or cations), The microcapsule membrane is impregnated with the desired anions or cations (this can be achieved, for example, by soaking the microcapsules in an anion or cation solution for several hours) and then reacts with these anions or cations to form insoluble A method of impregnating positive or negative ions to form salt may also be used.

Furthermore, in the above-mentioned opacification method, the concentration of the desired ions in the compound containing the desired ions in which the microcapsules are to be dispersed is preferably 0.1 to 3 molar, so that these ions can be well dispersed into the microcapsule membrane. can be infiltrated.

The dentifrice composition of the present invention contains opaque microcapsules produced by the method described above as an indicator, and when the brushing time or number of times reaches a certain level, the core substance (colored oily substance) is removed. The dentifrice composition changes color due to runoff, and a dentifrice composition that can clearly indicate the end point of brushing can be obtained.

Here, when this microcapsule is blended into a dentifrice composition such as toothpaste or toothpaste, it is preferable to use microcapsules with an average particle size of 5 to 100μ, and the amount of the microcapsules to be blended is When the blended dentifrice composition is applied, the microcapsules are ruptured and the core substance (colored oily substance) flows out, and a small amount is sufficient to color the dentifrice more or less vividly.

As other components of the dentifrice composition of the present invention, known components can be used, such as abrasives such as dibasic calcium phosphate, binders such as carboxymethyl cellulose, thickeners such as glycerin, and sodium lauryl sulfate. A dentifrice having a desired composition is produced by a conventional method by appropriately selecting ingredients such as a foaming agent, sweeteners, fragrances, preservatives, and various active ingredients. When the microcapsules are incorporated into a toothpaste composition, for example, in the case of toothpaste, water is added to the microcapsules obtained by the above method to form an aqueous dispersion of a predetermined concentration. It can be added to a separately prepared toothpaste and mixed until uniform, or in the case of powdered toothpaste, powders such as dibasic calcium phosphate or calcium carbonate can be mixed with the obtained microcapsules or its slurry to make it fluid. An appropriate blending method may be employed, such as drying by a drying method or the like, storing in powdered form, and adding and mixing this mixed powder to toothpaste powder at the time of preparation. Of course, it is also possible to directly mix the obtained microcapsules into a separately prepared toothpaste.

〔Effect of the invention〕

As is clear from the micrograph in Figure 1, the opaque microcapsules incorporated in the dentifrice composition of the present invention are at least partially embedded in the microcapsule membrane, with insoluble salt precipitated to cover the microcapsules. Due to the insoluble salt that is at least partially buried within the microcapsule membrane itself, the present invention uses a colored oily substance as the core material, which is colored.
The coloration can be hidden, and unlike conventional microcapsules whose surface is simply coated with inorganic salt, at least a portion of the salt is buried within the microcapsule membrane itself, so the salt can be mechanically peeled off. Moreover, even when used in water or an aqueous system, there is almost no shedding from the surface of the microcapsule membrane, and the microcapsule membrane is stably maintained and the color inside can be reliably hidden. Furthermore, the obtained microcapsules have low permeability of the core substance to the outside of the microcapsules and relatively high membrane strength.

Therefore, before use, a toothpaste composition containing such microcapsules shows no discoloration due to the colored oily substances contained in the microcapsules, and the membrane is destroyed by brushing in the oral cavity for a certain period of time. It is very easy to use because it gives a clear color change to the toothpaste and signals the end of brushing.

Next, reference examples and examples will be shown to further specifically explain the present invention. In addition, in the following examples, % represents weight %.

[Reference Example 1] 240 g of a 10% acid-treated gelatin aqueous dispersion was dissolved by heating to 80°C, and then maintained at 40 to 50°C. On the other hand, 70g cottonseed oil
1.0 g of β-carotene and 2.0 g of glycerin monostearate were dissolved in the gelatin aqueous solution and emulsified while being gradually added to the aqueous gelatin solution. Then add this emulsion to
10% aqueous gum arabic solution heated to 40-50℃ 240
After mixing 1,120 g of warm water at 40-50°C, the pH was adjusted with a 3N sulfuric acid aqueous solution while keeping the temperature at 40-50°C.
Adjust to 4.0-4.2. Next, the temperature of this solution was
Add 10% potassium alum aqueous solution to 40°C while keeping at 40°C.
Continue stirring for 4 hours after adding g. After stirring, the microcapsules were separated by centrifugation (2000 rpm, 5 minutes) and added to a 1% calcium chloride aqueous solution.
700g and stirred for 30 minutes to obtain white opaque microcapsules (average particle size 50μ).

When this opaque microcapsule was observed under a microscope, it was found that some of the calcium sulfate crystals were buried in the microcapsule membrane and precipitated on the surface. (See Figure 1. The magnification is 400 times, and one scale in Figure 1 is 2.5μ.) Furthermore, even if these microcapsules are stirred in water, they remain white, and the stirred microcapsules remain white. Even when the capsule was observed under a microscope, no crystals were found to be detached.

For comparison, in the above production method, PH was adjusted with 10% acetic acid instead of 3N sulfuric acid, and glutaraldehyde was used instead of potassium alum as a hardening agent.
After using 0.5g and adding glutaraldehyde,
Stirring was continued for 4 hours, and then the pH was adjusted to 8 with caustic soda, and the microcapsules were separated and produced by heating at 50°C for 1 hour. (10μ)). These microcapsules showed the color of the core substance.

[Reference Example 2] 465 g of 5.4% acid-treated gelatin aqueous dispersion is heated and then cooled to 50°C. On the other hand, coconut oil (melting point 22~
26℃) to 50℃, add paprika oleoresin and dissolve it, and the color value of capsanthin is determined.
Make it 20000 units. Next, 100 g of this was gradually added dropwise to the aqueous gelatin solution and emulsified at 50°C. At this time, glycerin monostearate
5.0g was used as emulsifier. Next, 50 g of a 5% aqueous solution of carboxymethyl cellulose (degree of etherification 0.6, average degree of polymerization 150) heated to 50° C. is added and mixed, and the pH is adjusted to 4.0 to 4.4 with a 3N aqueous phosphoric acid solution. The temperature of the system was lowered to 5°C, 8 g of a 30% formalin aqueous solution was added thereto, the pH was adjusted to 9.0 to 10.0 with a 3N aqueous sodium hydroxide solution, and the mixture was stirred for 1 hour. Thereafter, the microcapsules were separated by centrifugation (2000 rpm, 5 minutes), added to 800 g of a 5% calcium chloride aqueous solution, and stirred for 1 hour.
Opacified microcapsules are obtained by precipitation of calcium phosphate.

The obtained microcapsules exhibited good properties similar to those of Reference Example 1.

〔Example〕

The microcapsule slurry obtained in Reference Example 1 was blended into a toothpaste having the following composition so that β-carotene was 0.01%.

Dibasic calcium phosphate 500 parts by weight Sorbit 200 Sodium lauryl sulfate 20 Carboxymethyl cellulose 10 Satucalin 1 Flavor 10 Water 239 Total 980 20 parts by weight of the microcapsule slurry prepared by the above method for 980 parts by weight of this toothpaste was added and mixed slowly to obtain a toothpaste (containing 0.01% β-carotene).

This dentifrice remains white at the time of preparation and even after storage for one month at 40°C, and therefore the core substance is a colored oily substance (cottonseed oil colored with β-carotene).
As described above, the microcapsules according to the present invention are excellent in terms of opacity, are not permeable, and inorganic crystals (calcium sulfate) do not penetrate from the microcapsule membrane in an aqueous system. It was found that no desorption occurred.

The toothpaste containing the microcapsule slurry is white before use, but when brushing the teeth with it, the toothpaste has a brushing time of 1 to 2 hours.
After a few minutes, it turned yellow, thus confirming that the microcapsules could be effectively used as an indicator in, for example, an indicator toothpaste.

[Brief explanation of the drawing]

FIG. 1 is a photomicrograph showing the microcapsules used in the present invention, and FIG. 2 is a photomicrograph showing the microcapsules obtained by the conventional method.

Claims (1)

[Scope of Claims] 1. The core substance is formed of a colored oily substance, and an insoluble salt is precipitated to cover the microcapsule membrane while being at least partially buried in the microcapsule membrane itself, A dentifrice composition characterized in that it contains opaque microcapsules in which the color of the colored oily substance is concealed. 2. The dentifrice composition according to claim 1, wherein the insoluble salt is one or a mixture of two or more of calcium phosphate, calcium sulfate, calcium carbonate, barium phosphate, barium sulfate, and barium carbonate.