JPH0615405B2 - Calcium hydrogen phosphate dihydrate and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an abrasive base material for toothpaste used for toothpaste, profilakis paste, and the like, and more specifically, hydrogen phosphate having a low polishing and high cleaning function. The present invention relates to calcium dihydrate and a method for producing the same.

[Conventional technology]

The base material for oral compositions generally used for toothpaste, profilakis paste, etc., has a high ability to efficiently remove stains, plaque, food residue, etc. adhered to and deposited on teeth by physical action, and has a cleaning ability. Along with being excellent, it has a mild polishing property that does not damage the enamel of teeth,
In addition, it is desirable that it can laterally die plaque and tartar deposits. In this case, it is sufficient to increase the polishing power of the base material to enhance the cleaning function. However, if the polishing power is too high, the tooth surface may be damaged. Therefore, the base material has low polishing and has a high cleaning function. Those are preferable.

In view of the above, the present applicant has previously proposed a specific calcium hydrogen phosphate / anhydrate as a base material for an oral composition having a low-polishing / high-cleaning function (Japanese Patent Laid-Open No. 59-223204-22).
3208 publication).

[Problems to be solved by the invention]

The calcium hydrogen phosphate anhydrate according to the above proposal has an excellent low-polishing and high-cleaning function and is very effective as a base material for oral composition, but further has various low-polishing and high-cleaning functions. An oral composition substrate is desired.

In particular, calcium hydrogen phosphate dihydrate, which has been widely used as a base material, has a cleaning power and polishing power in comparison with each other. This calcium hydrogen phosphate dihydrate has the highest polishing power. Since it is a low-soft abrasive, it may not be able to exhibit sufficient tooth surface cleaning and whitening effects with an inappropriate brushing method or brushing time, so it provides a high cleaning effect while maintaining low polishing properties. Calcium hydrogen phosphate-2
Hydrates are desired. In addition, this is especially effective for cleaning the oral cavity of gingival recession, dentin exposure, and hypersensitivity of wedge defect. That is, with the recent tendency of aging society, the number of people with such gingival recession, dentin exposure, and wedge-shaped defect has increased in recent years, and interest in hyperesthesia has also increased. Regarding the above, conventionally, brushing using only a toothbrush or brushing using a toothpaste having an extremely low polishing power has been performed. But,
Polishing power is insufficient with these brushing methods,
Since the cleaning power is also low in proportion to this, a satisfactory tooth cleaning effect cannot be obtained. Therefore, there is a strong demand for a base material for an oral composition, particularly a calcium hydrogen phosphate dihydrate base material, which gives a sufficient cleaning effect even if the polishing power is low.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a calcium hydrogen phosphate dihydrate having an excellent low-polishing and high-cleaning function.

[Means and Actions for Solving Problems]

As a result of earnest studies to achieve the above object, the present inventors have found that, in the neutralization reaction of phosphoric acid with quick lime, slaked lime and / or calcium carbonate (hereinafter referred to as calcium compound part), bound phosphorus is used as a habit modifier. It was found that calcium hydrogen phosphate obtained by adding an acid or a salt thereof and a water-soluble aluminum salt and / or an iron salt has a good low-polishing and high-cleaning function.

That is, it is conventionally known to produce calcium hydrogen phosphate by a neutralization reaction between phosphoric acid and a calcium compound, and it is also possible to use condensed phosphoric acid or a salt thereof as a habit modifier during the neutralization reaction. It is known that calcium hydrogen phosphate / anhydride obtained by using condensed phosphoric acid or a salt thereof as a habit modifier in this way is used as a base for an oral composition having a low polishing and high cleaning function. It is also known to be used (publication of the above-mentioned publication), but the present inventors have found that more water-soluble aluminum is used during the neutralization reaction between phosphoric acid and a calcium compound using condensed phosphoric acid or a salt thereof as a habit modifier. Calcium hydrogen phosphate dihydrate obtained by adding salt and / or iron salt has a low polishing and high cleaning function not found in conventional calcium hydrogen phosphate dihydrate base materials. When the polishing power (amount of dentin wear) is equivalent to that of conventional calcium hydrogen phosphate dihydrate, the cleaning power (decontamination power) is higher than that, and when the cleaning power is the same. Has the effect of exhibiting a lower dentin wear amount. Therefore, this calcium hydrogen phosphate dihydrate has a low polishing power as a base material for an oral composition, but has an extremely superior cleaning effect as compared with the conventional one. To demonstrate
It was found that it is suitable for cleaning the oral cavity of the above-described gingival recession, dentin exposure, hypersensitivity of wedge-shaped defect, etc.

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

As described above, the calcium hydrogen phosphate according to the present invention is prepared by adding condensed phosphoric acid or a salt thereof together with a water-soluble aluminum salt and / or an iron salt as a habit modifier in the neutralization reaction between phosphoric acid and a calcium compound. It is manufactured. Here, when obtaining the calcium hydrogenphosphate dihydrate of the present invention, the concentration of phosphoric acid is 5 to 85% (% by weight, the same applies hereinafter), preferably 20 to 75%.

As the calcium compound, one kind or a mixture of two or more kinds of calcium oxide, calcium hydroxide, calcium carbonate and the like is used. Especially preferred is lime milk made of fine calcium hydroxide slurry. The concentration of the calcium compound is preferably 50 to 200 g / calculated as GaO.

In the present invention, these phosphoric acid and calcium compound are treated by a conventional method, for example, US Pat. Nos. 22,876,99 and 301,285.
No. 2, No. 3066056, No. 3169096 and Japanese Patent Publication No. 39-3272
No. 3,3273, the neutralization reaction is carried out. In this case, particularly in the case of obtaining calcium hydrogen phosphate dihydrate, the reaction temperature is preferably 50 ° C. or lower.

In this case, in the present invention, condensed phosphoric acid or a salt thereof is added as a habit modifier in the neutralization reaction of phosphoric acid with a calcium compound. Examples of the condensed phosphoric acid include polyphosphoric acids such as pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, hexapolyphosphoric acid, and decapolyphosphoric acid, and salts of these include alkali metals, alkaline earth metals,
Aluminum group metals are mentioned. In the present invention, one kind of these condensed phosphoric acids and salts thereof can be used alone or in combination of two or more kinds. The amount of the condensed phosphoric acid and the salt thereof used is preferably 0.1 to 50%, particularly preferably 1 to 20% with respect to the theoretical amount of CaHPO ₄ .2H ₂ O produced. If the amount used is less than 0.1%, the particle size of the primary particles becomes large and the polishing power is increased. If it is more than 50%, the surface of the agglomerated particles becomes too smooth, which may lower the polishing power and the cleaning power.
Condensed phosphoric acid and its salt may be added and mixed in phosphoric acid before the start of the neutralization reaction in advance, but it is preferable to add them separately from the calcium compound after the start of the neutralization reaction. As a method of addition, the amount necessary for the reaction may be added all at once, or may be added in several times. However, it is necessary to finish all the additions before the reaction.

Further, in the present invention, a water-soluble aluminum salt and / or iron salt is added, but the concentration of CaHPO ₄ ·.
0.1 to 10%, especially 0.5 to 5% of 2H ₂ O logic production
It is preferable that If the amount used is less than 0.1%,
The number of single particles that do not aggregate increases and the cleaning power decreases. Ten
%, No significant effect is obtained. In the present invention, the water-soluble aluminum salt and iron salt are
The seeds may be used or a mixture of two or more kinds may be used in combination. The water-soluble aluminum salt and / or iron salt may be added and dissolved in phosphoric acid before the start of the neutralization reaction, or may be dispersed and mixed in the calcium compound. Of the theoretical amount of phosphoric acid required for the reaction, preferably
It is advisable to divide a portion thereof and dissolve in it, and add it separately from the calcium compound after the initiation of the neutralization reaction.

The calcium hydrogen phosphate dihydrate of the present invention is used to add bound phosphoric acid or a salt thereof as a habit modifier, a water-soluble aluminum salt and / or an iron salt, the addition timing and the addition method thereof, and further reaction. A desired aggregate can be obtained by appropriately controlling the temperature, reaction time, stirring speed, and the like.

The base material for an oral composition of the present invention comprises the calcium hydrogen phosphate dihydrate obtained as described above, and such calcium hydrogen phosphate dihydrate is usually 0.1
It is an agglomerate composed of primary particles of ˜5 μm, and the average particle size of the agglomerate is 1 to 50 μm, and especially when the concentration of condensed phosphoric acid or its salt is 10% or more, the agglomerate has a spherical form. The size of the primary particles is a value measured and calculated from an electron micrograph, and the aggregated particle size is a value measured by a laser diffraction method.

The density of the calcium hydrogen phosphate dihydrate obtained as described above is usually 1.90 to 2.29 g / cm ³ (2
0 ° C.) and the specific surface area is ² to 50 m ² / g by the BET method,
This is the density of conventional calcium hydrogen phosphate dihydrate
2.306 g / cm ³ , specific surface area is 0.8 to 1.5 m ² / g,
Further, since the conventional calcium hydrogen phosphate dihydrate is a pulverized product of a flat single crystal, the physical properties thereof are different from those of the conventional calcium hydrogen phosphate dihydrate.

The base material for an oral composition of the present invention is used as a base material (abrasive material) in toothpaste, profilakis paste, etc., but its content in the oral composition is usually 5 to 95%, particularly 10 to 95. %. The other components of the oral composition containing the base material of the present invention are selected according to the type of the composition, and for example, for the preparation of dentifrice, a binder, a thickener, a surfactant, and a fragrance. , Sweeteners, preservatives and various active ingredients are mixed.
When an oral composition is prepared using the base of the present invention, it is preferable to add tribasic magnesium phosphate in order to prevent the pH of the oral composition from lowering and solidifying to improve the stability of the system. In this case, it is preferable to add 0.1 to 3%, particularly 0.5 to 2%.

〔The invention's effect〕

The base material for an oral composition comprising calcium hydrogen phosphate dihydrate of the present invention has a higher cleaning effect than the conventional one when the polishing power is equivalent to that of the conventional calcium-based base material,
Further, when the cleaning effect is the same, it has a low polishing and high cleaning function that the polishing power is low. That is, for the normal healthy person, the one that conventionally required 3 minutes of brushing can achieve the whitening effect in a shorter brushing time, and the one having the same brushing time further improves the whitening effect. It has extremely favorable properties in terms of safety and hygiene.

Further, it exerts an excellent effect of giving an excellent cleaning effect to a person having an exposed root, gingival recession, dentin exposure, wedge-shaped defect, and the like, although the polishing power is extremely low.

〔Example〕

Hereinafter, the present invention will be described more specifically by showing production examples of the base material of the present invention.

Primary particle size Measured and calculated from electron micrographs.

"MICROTRAC PARTICLE ・ SIZE" made by Leeds & Northrup
It was measured using "ANALYZER".

Specific surface area Measured using "QUANTA SORB" manufactured by Yuasa Battery Co., Ltd.

The density was measured using a pycnometer and calculated by the following calculation formula.

M _O : Pycnometer weight M _S : Pycnometer weight + powder weight _ML : Pycnometer liquid (water) weight to 100% M _SL : Pycnometer weight + Weight of powder + Weight of liquid ρ _L : Density of liquid (water) at 20 ° C ρ _P : Density of powder at 20 ° C Example 1 (1) Preparation of lime milk Lime milk was prepared by pouring 380 g of quick lime into hot water with stirring and continuing stirring for 30 minutes. As a result of removing coarse particles by sieving the lime milk through a 100-mesh sieve, the concentration of the lime milk obtained was 12 in terms of CaO.
It was 8 g /.

(2) Production of calcium hydrogen phosphate 12 g of aluminum phosphate was dissolved in 50% aqueous phosphoric acid solution 1, heated to 40 ° C., and the lime milk prepared in (1) was added at a rate of 600 ml / h with stirring. When about 200 ml of lime milk was added, pyrophosphoric acid was added at a rate of 0.46 g / min in parallel with the addition of lime milk. When the pH of the reaction solution reached 6.5, the addition of lime milk and pyrophosphoric acid was stopped, and only stirring was continued for another 30 minutes to complete the reaction.

The total amount of lime milk and pyrophosphoric acid added during this reaction were 3.2 and 31 g, so the amount of pyrophosphoric acid added was
7.9 parts by weight.

After that, the reaction solution is filtered, the filter cake is washed with water, and then at 50 ° C.
By drying for 12 hours, aggregated calcium hydrogen phosphate was obtained.

The obtained calcium hydrogen phosphate was an agglomerate composed of primary particles with an average of 1.0 μm, the average particle size of the particles was 15 μm, the density was 2.08 g / cm ³ , and the specific surface area was 12 m ² / g.

Examples 2 to 6 Calcium hydrogen phosphate was produced in exactly the same manner as in Example 1 except that the amount of pyrophosphoric acid added was changed as shown in Table 1. The characteristics of the obtained calcium hydrogen phosphate are shown in Table 1.

Examples 7 to 12 Calcium hydrogen phosphate was produced in the same manner as in Example 1 except that polyphosphoric acid shown in Table 2 was used instead of pyrophosphoric acid. The characteristics of the obtained calcium hydrogen phosphate are shown in Table 2.

Examples 13 to 15 In Example 1, the addition amount of aluminum phosphate is shown in the table.
Calcium hydrogen phosphate was produced in exactly the same manner as in Example 1 except that the changes were made as in 3. The characteristics of the obtained calcium hydrogen phosphate are shown in Table 3.

Examples 16 to 19 In Example 1, instead of aluminum phosphate, Table-
Calcium hydrogen phosphate was produced in exactly the same manner as in Example 1 except that the compound as in Example 4 was used. The characteristics of the obtained calcium hydrogen phosphate are shown in Table 4.

Examples 20 to 21 Calcium hydrogen phosphate was produced in the same manner as in Example 1 except that slaked lime and calcium carbonate were used instead of quick lime. The characteristics of the obtained calcium hydrogen phosphate are shown in Table 5.

Examples 22 to 24 Calcium hydrogen phosphate was produced in exactly the same manner as in Example 1 except that the stirring speed was changed as shown in Table-6. The characteristics of the obtained calcium hydrogen phosphate are shown in Table-6.

Comparative Example 1 Calcium hydrogen phosphate was produced in the same manner as in Example 1 except that pyrophosphoric acid was not added in Example 1. The obtained calcium hydrogen phosphate has an average of 80 in which the primary particles of plate crystals of 10 to 50 μm are aggregated.
μm particles, specific surface area 1.8 m ² / g, density 2.31 g / cm
^{Was 3} .

Comparative Example 2 Calcium hydrogen phosphate was produced in the same manner as in Example 1 except that aluminum phosphate was not added. The obtained calcium hydrogen phosphate was a plate-like crystal with primary particles of 2 to 20 μm and was not aggregated. The specific surface area was 1.9 m ² / g and the density was 2.31 g / c.
It was m ³ .

Reference Example The calcium hydrogen phosphate dihydrate of the present invention has a more appropriate polishing power for teeth and a higher cleaning power than conventional anhydrous dibasic calcium phosphate and the like. Will be explained. First, the evaluation method will be described.

Polishing power was measured by adding 50 g of calcium hydrogen phosphate dihydrate or conventional dicalcium diphosphate dihydrate (7.5 g) to 50% glycerin aqueous solution containing 0.6% tragacanth gum.
Using a suspension suspended in g, a silver plate was brushed 3000 times in 1 hour with a load of 240 g by a flat plate polishing tester to measure the amount of wear of the silver plate.

On the other hand, the method of measuring the cleaning power is to collect tobacco tar by a normal method, apply this as a solution and evenly compress on the tiles.
After heating and drying, this was set in a polishing container and brushed 300 times under a load of 240 g using a suspension prepared by suspending 2.5 g of various calcium phosphate in 47.5 g of 95% glycerin aqueous solution in the same manner as in the method for measuring the polishing force. After polishing, the removal rate of tobacco tar in the tile was visually evaluated.

Table-7 Evaluation Criteria Rating 1: Cigarette tar removal rate 0-10% 2: 〃 11-20% 3: 〃 21-30% 4: 〃 31-40% 5: 〃 41-50% 6: 〃 51-60 % 7: 〃 61 to 70% 8: 〃 71 to 80% 9: 〃 81 to 90% 10 〃 91 to 100% The results of measuring the silver plate polishing power and cleaning power by the above measurement method are as follows. It can be proved that the calcium hydrogen phosphate of the present invention has a high cleaning power even though it has a low polishing power.

Claims (2)

[Claims] 1. A density of 1.90 to 2.29 g / cm ³ and a specific surface area of 2.
Calcium hydrogen phosphate dihydrate having an average particle size of 1 to 50 μm, which is formed by agglomeration of primary particles having a particle size of ˜50 m ² / g and a particle size of 0.1 to 5 μm. 2. Condensed phosphoric acid or its compound as a habit modifier in a neutralization reaction at 50 ° C. or lower with any one or more of calcium compounds consisting of calcium consisting of quick lime, slaked lime and calcium carbonate of phosphoric acid. A density of 1.90 to 2.29 g / characterized by adding water-soluble aluminum salt and / or iron salt together with addition of salt
A method for producing calcium hydrogen phosphate dihydrate having cm ³ , a specific surface area of ² to 50 m ² / g, and an average particle diameter of 1 to 50 µm formed by agglomeration of primary particles having a particle diameter of 0.1 to 5 µm.