JPH072504A - Production of calcium hydrogenphosphate-dihydrate - Google Patents

Abstract

PURPOSE:To obtain calcium hydrogenphosphate dihydrate having high cleaning function while keeping low abrasion by adding condensed phosphoric acid or its salt as a habit modifier in neutralization reaction of phosphoric acid with quick lime, slaked lime or calcium carbonate. CONSTITUTION:In neutralization reaction of phosphoric acid with either one or two kinds of calcium compounds consisting of quick lime, slaked lime or calcium carbonate at <=50 deg.C, this method for producing calcium hydrogenphosphate.dihydrate is carried out as follows: >=10 pts.wt., preferably 20-50 pts.wt. (expressed in terms of P2O7) of condensed phosphoric acid or its salt as a habit modifier based on 100 pts.wt. of the resultant calcium hydrogenphosphate dihydrate is added to provide the objective calcium hydrogenphosphate dihydrate. The above dihydrate is a calcium hydrogen phosphate.dihydrate having 1.9-2.29g/cm<3> density, 10-50m<2>/g specific surface area and 10-50mum maverage particle diameter and obtained by aggregating primary particles having 0.01-0.9mum particle diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abrasive base material for toothpaste used for toothpaste, profilakis paste and the like. More specifically, it is a calcium hydrogen phosphate dihydrate having a low polishing and high cleaning function. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Oral composition base materials generally used in toothpaste, profilakis paste, etc. have the ability to efficiently remove stains, plaque, food residue, etc. that adhere to or deposit on teeth by physical action. What is desired is a material that is high in cleaning ability, has a mild abrading property that does not damage tooth enamel, and can prevent plaque and tartar deposition. 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 / anhydrous as a base material for an oral composition having a low-polishing and high-cleaning function (Japanese Patent Laid-open No. Sho 5).
9-223204 to 223208).

[0004]

The calcium hydrogen phosphate / anhydrate according to the above-mentioned proposal has an excellent low polishing / cleaning function and is very effective as a base material for oral compositions. A base material for an oral composition having various low-polishing and high-cleaning functions is desired.

In particular, calcium hydrogen phosphate dihydrate, which has been widely used as a base material, has a cleaning power proportional to polishing power. This calcium hydrogen phosphate dihydrate is Since it is the softest abrasive with the lowest polishing power, it may not be possible to achieve sufficient tooth surface cleaning and whitening effects with an inappropriate tooth brushing method or tooth brushing time. Calcium hydrogen phosphate dihydrate that exerts an effect is 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 defect has increased recently, and interest in hyperesthesia is also increasing. As for oral cavity cleaning, brushing using only a toothbrush or brushing using a toothpaste having an extremely low polishing power has been conventionally 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,
It is an object of the present invention to provide calcium hydrogen phosphate dihydrate having an excellent low polishing and high cleaning function.

[0008]

Means and Actions for Solving the Problems The present inventors have
As a result of intensive studies to achieve the above object, in the neutralization reaction of phosphoric acid with quick lime, slaked lime and / or calcium carbonate (hereinafter referred to as calcium compound part), condensed phosphoric acid or a salt thereof is produced as a habit modifier. Calcium hydrogen phosphate dihydrate obtained by adding 10 parts by weight or more, preferably 20 parts by weight to 50 parts by weight to 100 parts by weight of calcium hydrogen phosphate dihydrate has a good low polishing height. It was discovered that it has a cleaning function.

It has been conventionally known to produce calcium hydrogen phosphate by a neutralization reaction between phosphoric acid and a calcium compound, and in the neutralization reaction, condensed phosphoric acid or a salt thereof is used as a stabilizer of calcium hydrogen phosphate. Is known to be added. In addition, calcium hydrogen phosphate / anhydride obtained by using condensed phosphoric acid or a salt thereof as a habit modifier may be used as a base material for an oral composition having a low polishing and high cleaning function. It is publicly known (published above).

The present inventors obtained by carrying out the neutralization reaction of phosphoric acid with a calcium compound in the presence of a larger amount of condensed phosphoric acid or a salt thereof than the amount that has been added as a stabilizer until now. Compared with conventional calcium hydrogen phosphate dihydrate, calcium hydrogen phosphate dihydrate has a low-polishing and high-cleaning function not found in conventional calcium hydrogen phosphate dihydrate base materials. If the polishing power (amount of dentin wear) is equal, the cleaning power (decontamination power) is higher than that,
When the cleaning power is the same, it 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 oral composition, while it has a low polishing power. It was found that it exhibits a cleaning effect that is far superior to that of the above-mentioned ones, and is suitable for cleaning the oral cavity of the above-described gingival retraction, dentin exposure, and sensation of wedge-shaped defect hypersensitivity.

The present invention will be described in more detail below.
The calcium hydrogen phosphate according to the present invention is produced in the presence of condensed phosphoric acid or a salt thereof as a habit modifier in the neutralization reaction between phosphoric acid and a calcium compound as described above.

As the calcium compound, 1 such as calcium oxide, calcium hydroxide and calcium carbonate can be used.
One kind or a mixture of two or more kinds is used. Especially preferred is lime milk made of fine calcium hydroxide slurry. Note that the concentration of the calcium compound depends on the mechanical operation such as stirring or pumping a viscous substance such as lime milk and CaO.
It is suitable that the amount is 50 to 200 g / liter in terms of conversion.

In the present invention, these phosphoric acid and calcium compound are treated by a conventional method, for example, US Pat. No. 22,87699.
No. 3012852, No. 3066056, No. 3106096, and No. 39-3272, No. 3273, the neutralization reaction is carried out. In this case, calcium hydrogen phosphate. When obtaining a hydrate, the reaction temperature must be 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 condensed phosphoric acid include polyphosphoric acid such as pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, hexapolyphosphoric acid, and decapolyphosphoric acid, and examples of these salts include alkali metals, alkaline earth metals, and aluminum group metals. 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 these condensed phosphoric acids and salts thereof to be used is preferably 10 parts by weight or more, particularly 20 to 50 parts by weight, based on the theoretical amount of CaHPO ₄ .2H ₂ O produced. When the amount used is less than 10 parts by weight, the cohesiveness of the primary particles is poor, and when the amount of the single particles is 20 parts by weight or less, the particles are particularly dispersed as they are, so that the polishing property is low but the cleaning property is low. 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, and a large amount of large-sized particles may be generated, which may cause foreign matter in the oral cavity. It is not suitable for use as a toothpaste as it feels.

The 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 preferably added separately from the calcium compound after the start of the neutralization reaction. Is good.

As a method of addition, the amount required for the reaction may be added all at once, divided into several times, or continuously added during the reaction time. However, it is necessary to finish all the additions before the reaction.

In the case of calcium hydrogen phosphate according to the present invention, the amount of condensed phosphoric acid or a salt thereof as a habit modifier, its addition timing and its addition method, and further the reaction temperature, reaction time, stirring speed, etc. should be controlled appropriately. The desired aggregate can be obtained by.

The base material for oral composition obtained by the present invention is composed of the calcium hydrogen phosphate obtained as described above, and the calcium hydrogen phosphate is usually from 0.01 to 0.9 μm of primary particles. The aggregate has an average particle size of 10 to 50 μm, and particularly when the amount of condensed phosphoric acid or its salt added is 20% or more, the aggregate has a spherical shape.

The calcium hydrogen phosphate dihydrate obtained as described above usually has a density of 1.9 to 2.29.
g / cm ³ (20 ° C.), specific surface area is 10-50 m ² / by BET method
The density of conventional calcium hydrogen phosphate dihydrate is 2.306 g / cm ³ , and the specific surface area is 0.8 to 1.5 m.
² / g, and since the conventional calcium hydrogen phosphate dihydrate is a crushed product of a flat single crystal, the physical properties are different from those of the conventional calcium hydrogen phosphate dihydrate. is there.

The base material for an oral composition according to the present invention is used as a base material (abrasive) in toothpaste, profilakis paste and the like, and the amount of the base material to be incorporated into the oral composition is usually 5 to 95.
%, Especially 10-95%. The other components of the oral composition with which the above-mentioned base material is blended are selected according to the type of the composition and the like. For example, for the preparation of toothpaste, a binder, a thickener,
Surfactants, flavors, sweeteners, preservatives, various active ingredients, etc. are mixed. When an oral composition is prepared using this base material, 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. If 0.1-0.3%, especially
It is preferable to add 0.5 to 2%.

[0022]

[Effects of the Invention] Calcium hydrogen phosphate-2 according to the present invention
Compared to conventional calcium-based base materials, hydrate-based base materials for oral compositions have a higher cleaning effect than conventional ones when the polishing power is equivalent, and when the cleaning effects are equivalent, polishing It has a low polishing and cleaning function with low power. 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, while having an extremely low polishing force.

[0023]

EXAMPLES The present invention will now be described more specifically by showing production examples of the substrate according to the present invention.

[0024] was calculated measured from the primary particle diameter of electron micrographs.

Average particle size Leeds &Northrup's"MICROTRAC PARTICLE ・ SIZE A
It was measured using "NALYZER".

The specific surface area was 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 M _L : Pycnometer weight when liquid (water) is filled 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 3 liters of hot water heated to 80 ° C. with stirring and continuing stirring for 30 minutes. As a result of sieving the lime milk through a 100-mesh sieve to remove coarse particles, the concentration of the obtained lime milk was 129 g / liter in terms of CaO.

(2) Production of calcium hydrogen phosphate 1 liter of 50% phosphoric acid aqueous solution is heated to 40 ° C. and stirred 5
The lime milk prepared in (1) was added at a rate of 90 ml / h. When about 200 ml of lime milk was added, pyrophosphoric acid was added at a rate of 1.43 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 in order to complete the reaction. Since the total amounts of lime milk and pyrophosphate added during this reaction were 3.1 liters and 293 g,
The amount of pyrophosphoric acid added corresponds to 25 parts by weight. After that, the reaction solution was filtered, the filter cake was washed with water, and then dried at 45 ° C. for 12 hours to obtain an aggregated calcium hydrogen phosphate.

The obtained calcium hydrogen phosphate has an average
Aggregate consisting of 0.3 μm primary particles, average particle size of 17 μm, density 2.01 g / cm ³ , specific surface area 30 m ² / g
Met.

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

(Examples 7 to 12) Calcium hydrogen phosphate was prepared in the same manner as in Example 1 except that condensed phosphoric acid shown in Table 2 or a salt thereof was used in place of pyrophosphoric acid. Was manufactured. The properties of the obtained calcium hydrogen phosphate are shown in Table 2.

(Examples 13 to 14) Calcium hydrogen phosphate was produced in exactly the same manner as in Example 1 except that slaked lime and calcium carbonate were used instead of quick lime. The properties of the obtained calcium hydrogen phosphate are shown in Table 3.

(Examples 15 to 17) 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 4. The characteristics of the obtained calcium hydrogen phosphate are shown in Table 4.

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 is an average particle size of 80 μm in which primary particles of 10 to 50 μm plate crystals are aggregated, and the specific surface area is 1.8 m.
^The density was ² / g and the density was 2.31 g / cm ³ .

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

REFERENCE EXAMPLE REFERENCE EXAMPLE The calcium hydrogen phosphate of the present invention has a more appropriate polishing power for teeth and a higher cleaning power than the conventional anhydrous dicalcium phosphate and the like. Explain that First, the evaluation method will be described.

The measuring method of the polishing power is calcium hydrogen phosphate dihydrate, the conventional dicalcium phosphate dihydrate.
Using a suspension consisting of 7.5 g suspended in 15 g of 50% glycerin aqueous solution containing 0.6% tragacanth rubber, a silver plate was brushed 3000 times in 1 hour with a flat polishing tester at a load of 240 g to measure the amount of wear of the silver plate. did.

On the other hand, the method for measuring the cleaning power is to collect tobacco tar by a usual method, apply this to a tile evenly as a solution, heat and dry it, and then set it in a polishing container. Various calcium phosphates as in the polishing force measurement method
Using a suspension prepared by suspending 2.5 g of 47.5 g of 95% glycerin aqueous solution, brushing was carried out 300 times under a load of 240 g, and after polishing, the removal rate of tobacco tar in the tile was visually evaluated.

[0043]

[Table 5]

The results of measuring the polishing power and the cleaning power of the silver plate by the above measuring method are as follows. The calcium hydrogen phosphate of the present invention has a high cleaning power in spite of the low polishing power. I was able to prove that

[0045]

[Table 6] Note: As a conventional dicalcium phosphate dihydrate, a product manufactured by Toyo Stoufer Chemical Co. was used.

Claims (2)

[Claims] 1. Condensed phosphoric acid or a salt thereof as a habit modifier in a neutralization reaction at 50 ° C. or lower by any one or more of calcium compounds consisting of quick lime, slaked lime and calcium carbonate of phosphoric acid, 100 parts by weight of calcium hydrogen phosphate dihydrate produced is converted into P ₂ O ₇
The density characterized by adding 10 parts by weight or more is 1.9 to 2.
29 g / cm ³ , specific surface area 10-50 m ² / g, particle size 0.01-0.
Average particle size of 10 to 50 μm formed by agglomeration of 9 μm primary particles
A method for producing calcium hydrogen phosphate dihydrate. 2. The condensed phosphoric acid or the additive of the acid is P ₂ O.
Calcium hydrogen phosphate dihydrate produced in terms of ₇ 1
20 to 50 parts by weight with respect to 00 parts by weight.
A method for producing the described calcium hydrogen phosphate dihydrate.