Cosmetic Products Containing a Soluble Glass

This invention relates to liquid-based cosmetic products, particularly to those exhibiting excellent antibacterial property due to metal ion-discharge from soluble glass particles contained.

Liquid-based cosmetics, such as skin lotion, shampoo or rinse, are generally used in our daily life and have been mass-produced in factories. These products are directly applied to human skin, so that the manufacturing process has been strictly controlled for preventing bacterial contamination upon the products. However, after unsealing the package for usage, bacteria or mold may intrude into and grow in the cosmetics, so that various antibacterial agent has been added to the cosmetics.

Hagiwara et al. (U.S. Pat. No. 4,911,898) and Yamamoto et al. (U.S. Pat. No. 4,906,464) proposed liquid cosmetic products containing zeolite-based inorganic antibacterial agent. In these cosmetics, fine zeolite particles supporting antibacterial metal ions, such as Ag.sup.+, Cu.sup.+ or Cu.sup.2+, Zn.sup.2+ and so on (represented by Ag.sup.+, hereinafter), are blended as an antibacterial agent. The Ag.sup.+ ions are adsorbed in the pores of the particles as conceptually illustrated in FIG. 3(a), and discharged therefrom due to a chemical ion-exchange reaction between the alkaline metal ions, such as Na.sup.+ or K.sup.+ (represented by Na.sup.+, hereinafter), in the liquid cosmetic base. The discharged Ag.sup.+ ions are to exhibit antibacterial property.

As is shown in FIG. 4(a), the rate of Ag.sup.+ ion-discharge is determined by the concentration equilibrium between the Na.sup.+ and Ag.sup.+ in the cosmetic base. When Ag.sup.+ ions are consumed by the sterilization process, said ion-exchange reaction proceeds for keeping the equilibrium as shown in FIG. 4(b). Thus, the cosmetic product is to maintain an almost constant concentration of the discharged Ag.sup.+ and its sterilizing ability until all Ag.sup.+ ions are consumed.

Because of such Ag.sup.+ discharging mechanism, the conventional zeolite-based cosmetics appear to have following disadvantages.

(1) The rate of Ag.sup.+ ion-discharge from the zeolite particle is determined by said concentration equilibrium and greatly influenced by the environmental ion concentration. Ag.sup.+ discharging rate is to be controlled only by an adjustment of the Na.sup.+ concentration in the cosmetic base. Na.sup.+ ions are, however, added in a form of an alkaline component, and the range of addition is very limited for maintaining a suitable pH value of the cosmetics. In other words, it is substantially impossible to control the Ag.sup.+ ion-discharge for such cosmetic products. Therefore, the concentration of Na in the recipe of cosmetics often becomes excess or short for obtaining an optimum ion-discharging rate, thereby causing a lack of duration in the antibacterial effect due to a drastic discharge of Ag.sup.+ ions from zeolite particles, or insufficiency of antibacterial effect due to a lack of Na.sup.+ for promoting said chemical ion-exchange, respectively. Furthermore, it is difficult to obtain neutral or weak acidic cosmetics since the recipe is to inevitably contain alkaline components as a source of Na.sup.+, and the variety of cosmetic products is limited.

(2) The ion exchange reaction between Ag.sup.+ and Na.sup.+ may proceed catastrophically on a Na.sup.+ -rich human skin. In this case, enormous amount of Ag.sup.+ ions are to be discharged at once as shown in FIG. 3(b), and considerable part of discharged Ag.sup.+ ions may be reduced to metallic Ag particles by exposure to light, thereby causing a phenomenon that the cosmetics applied on the face turn slightly black.

(3) When such zeolite-based cosmetics are preserved under exposure to strong light, the amount of Ag.sup.+ ions in the cosmetics decreases since they are extensively reduced to metallic Ag particles. This may shorten the duration of antibacterial effect and cause the color change of cosmetics.

The object of this invention is to offer a cosmetic product containing inorganic antibacterial agent which exhibits excellent duration of antibacterial effect and does not cause catastrophic discharge of metallic ions when it is applied on a human skin.

For solving the aforementioned object, the cosmetic product relating to this invention comprises soluble glass particles and liquid cosmetic base containing water. The soluble glass contains antibacterial metal ions selected from the group consisting of Ag.sup.+, Cu.sup.+, Cu.sup.2+ and Zn.sup.2+, which elute from said soluble glass particles with the dissolution of said soluble glass into water. In this specification, "antibacterial" is to contain a meaning of destructive to or inhibiting the growth of not only bacteria but also mold or other fungi.

This cosmetic product exhibits an antibacterial property due to metal ions discharged from the soluble glass particles. The ion discharging mechanism thereof is essentially different from that of zeolite particles in the conventional cosmetics. That is to say, the antibacterial metal ions (antibacterial ions, hereinafter) contained are forming a solid solution with the components of soluble glass as schematically illustrated in FIG. 1, and as shown in FIG. 2, the antibacterial ions elute along with the physical dissolution of the soluble glass skeletal network, not due to a chemical ion exchange mechanism. Such mechanism of ion elution brings about the following unique advantages.

(1) It is very easy to control the eluting rate of antibacterial ions by adjusting the size or composition of the soluble glass particle regardless of the environmental concentration of Na.sup.+. Therefore, long term duration of antibacterial effect is easily achieved only by setting the size or composition of the soluble glass to a designated value, and the cosmetics can be preserved in a good condition for a long time even after unsealing the package. Furthermore, the addition of alkaline-metal ions, such as Na.sup.+, are no longer necessary for maintaining the ion-discharge, so that neutral or weak acidic cosmetics can be easily obtained. Even if an addition of such an alkaline component is required to achieve other purpose (pH value adjustment, for example), the quantity of addition thereof can be chosen in a wide range. Thus, much variety of cosmetics can be realized.

(2) The eluting rate of antibacterial ions from the soluble glass particles are controlled well even on a Na.sup.+ -rich human skin, since the ions elute due to the physical dissolution of the soluble glass, not due to the chemical ion exchange reaction. Therefore, there is no need to worry about drastic discharge of ions as observed in the conventional zeolite-based cosmetics.

(3) In the case that the antibacterial ions are photosensitive Ag.sup.+, the amount of eluted Ag.sup.+ ions never decreases drastically during the preservation of the cosmetics under exposure to light, since the decrease in the amount of eluted Ag.sup.+ ions due to the photochemical reduction never affects the solubility of the glass particles.

The cosmetic base used in this invention can comprise a liquid material selected from the group consisting of liquid foundation, skin lotion, milky lotion, shampoo, hair rinse and cream. In this case, the cosmetic products preferably contains more than 40 wt % of water in the recipe thereof. When the cosmetic base is a liquid material selected from the group consisting of skin lotion, milky lotion, shampoo and hair rinse, the cosmetic products preferably contain more than 65 wt % of water in the recipe thereof for maintaining a sufficient flowability.

As the soluble glass for this invention, a borosilicate glass or a phosphate glass is preferably used. A conventional sodium glass has a strong three-dimensional skeletal network structure consisting of Si.sup.4+, Na.sup.+ and O.sup.2-, and the ionic bonding in the network is so strong that the solubility of the conventional glass in water is almost zero. On the other hand, the soluble glass used in this invention is, however, prepared by melting B.sub.2 O.sub.3 or P.sub.2 O.sub.5 along with the common raw material of conventional glass. B.sub.2 O.sub.3 or P.sub.2 O.sub.5 component weakens the bonding of the network and make the skeletal network itself soluble in water. The net work structure of the glass is weakened with increasing the content of B.sub.2 O.sub.3 or P.sub.2 O.sub.5, thereby causing an increase in the solubility of the glass in water. Therefore, adjusting the solubility of the glass by changing the content of B.sub.2 O.sub.3 or P.sub.2 O.sub.5 is one of the effective methods for controlling the eluting rate of antibacterial ions from the glass particles.

As the antibacterial ions, Ag.sup.+, Cu.sup.+ or Cu.sup.2+ (particularly Ag.sup.+) is used preferably. It is traditionally known that a silver or copper vessel for food can prevent rotting of the food. This is due to the fact that a very slight amount of silver or copper ion is eluted from the silver or copper vessel. It is said that about 20 .mu.g/l of silver in a solution indicates a bactericidal action. In general, silver or copper ions in even a very slight amount can exhibit an action what is called "oligodynamic metal effect" to prevent growing of fungi or the like. Such metal ions are capable of being bonded to an activating enzyme center in a cell of bacterium or mold to exhibit a strong bactericidal action.

As the source of Ag.sup.+, Cu.sup.+ or Cu.sup.2+, metal oxides such as Ag.sub.2 O, Cu.sub.2 O or CuO are preferably used. These oxides are blended to the starting material of the soluble glass.

The soluble glass used for this invention can be prepared by any method like that of an ordinary glass. For example, a batch of glass material adjusted to a designated composition may be heated to be vitrified. Alternatively, the soluble glass may be manufactured by a sol-gel method. In this method, each oxide as the starting material is prepared as a sol of metal-oxide hydrate, which is obtained by hydrolysis of metallic ions or metal alkoxide. A mixture containing designated amount of each sol is evaporated, and then the objective soluble glass is to be obtained.

Both in the methods mentioned above, the blended metal ions are mixed homogeneously in a molten or liquid state, and the distribution of the metal ions is so uniform all over the particle that the antibacterial effect can endure until the soluble glass particles dissolve up. To the contrary, the zeolite particles used for the conventional cosmetics never dissolve into water, and the metallic ions are supported only on the surface of the particles, so that the supported ions are depleted in a relatively short period, and long term duration of the antibacterial effect cannot be expected.

Then, the soluble glass obtained are pulverized to a designated particle size. More specifically, the cosmetic products of this invention may be manufactured by crushing the soluble glass obtained into beads having an average particle size of about 2-10 mm, adding a desired amount of the beads into a vessel containing water in a recipe of the cosmetic products, and enclosing the beads in the vessel under a condition that the beads always contacts with the water.

As a typical composition of the soluble glass, a borosilicate glass containing B.sub.2 O.sub.3, SiO.sub.2, Na.sub.2 O and Ag.sub.2 O are preferably used. In this case, the composition should preferably contain 10-30 mol % of B.sub.2 O.sub.3, 40-60 mol % of SiO.sub.2, 20-40 mol % of Na.sub.2 O and 0.1-2 wt. % of Ag.sub.2 O. B.sub.2 O.sub.3 content less than 10 mol % may cause a crystallization of the material which leads to an insufficiency of the glass solubility, and more than 30 mol % of B.sub.2 O.sub.3 may cause an excess solubility of the glass and a consolidation of the particles due to a high hygroscopicity of the glass. SiO.sub.2 and Na.sub.2 O are the fundamental components for maintaining the strength of the skeletal network of the glass, so that the content under the lower limit of the range indicated above may lead to an excess solubility of the glass and the content over the upper limit of the range may cause lack of the glass solubility. On the other hand, less than 0.1 wt % of Ag.sub.2 O may cause a lack of the antibacterial effect, and more than 2 wt % of Ag.sub.2 O may bring about an excess elution of Ag.sup.+ which leads to a color change of the cosmetics due to a generation of metallic Ag particles. It is more preferable that the glass composition contain 15-25 mol % of B.sub.2 O.sub.3, 45-55 mol % of SiO.sub.2, 25-35 mol % of Na.sub.2 O and 0.1-2 wt % of Ag.sub.2 O.

One more typical composition of the soluble glass which can be preferably applied to this invention is a phosphate glass containing P.sub.2 O.sub.5, at least one of CaO and MgO, Al.sub.2 O.sub.3 and Ag.sub.2 O. In this case, the composition should preferably contain 38-58 mol % of P.sub.2 O.sub.5, 32-52 mol % of at least one of CaO and MgO in total, 6-14 mol % of Al.sub.2 O.sub.3 and 0.1-2 wt % of Ag.sub.2 O. The critical meaning of the ranges for P.sub.2 O.sub.5 and Ag.sub.2 O are equivalent to those of B.sub.2 O.sub.3 and Ag.sub.2 O for said borosilicate glass, respectively. Furthermore, the CaO and/or MgO and Al.sub.2 O.sub.3 function as the network-strengthening component, so that the critical meaning of the indicated content range thereof corresponds to those o the SiO.sub.2 and Na.sub.2 O for aforementioned borosilicate glass. It s more preferable that the glass composition contains 43-53 mol % of P.sub.2 O.sub.5, 37-47 mol % of at least one of CaO and MgO in total 8-12 mol % of Al.sub.2 O.sub.3 and 0.1-2 wt % of Ag.sub.2 O.

Since the antibacterial ions elutes due to the physical dissolution of the soluble glass, the rate of elution of antibacterial ions from the soluble glass particles can be easily controlled by, for example, adjusting the chemical composition of soluble glass or regulating the size and distribution of the soluble glass particles. Therefore, it is very easy to control the magnitude of antibacterial effect and the duration of the effect corresponding to the variety of cosmetic products. In the conventional zeolite-based cosmetics, the discharging rate of the antibacterial ions are determined by the ion concentration equilibrium regarding said chemical ion exchange reaction, so that it is almost impossible to control the discharging rate with adjusting the size or the composition of the zeolite particles.

The soluble glass is pulverized into particles. The average particle size is preferably set in a range of less than 20 .mu.m. When the average particle size exceeds 20 .mu.m, the glass particles become too coarse to achieve a comfortable fitting to a human skin. The average particle size is preferably set in a range of less than 10 .mu.m, and further more preferably in a range of less than 5 .mu.m or less.

For aforementioned phosphate glass, CaO and MgO components can be blended separately or simultaneously. In the case of separate blending, the glass containing MgO tends to exhibit a lower solubility than that containing the same mole fraction of CaO. This means that using MgO is advantageous for preparing cosmetics containing very fine glass particles because the glass particles become more water-resistive. Specifically, the content of MgO in the soluble glass is preferably set in a range of 37-47 mol %, and the average particle size is preferably set to be 1 .mu.m or less. Such mode are particularly suitable for cosmetics, which contains more than 70 wt % of water in the recipe thereof, and wherein the cosmetic base comprises a liquid material selected from the group consisting of skin lotion, milky lotion, shampoo and hair rinse. In this case, the soluble glass particles may be suspended in the liquid cosmetic base.

The rate of eluting of said antibacterial metal ions in water from the soluble glass is preferably set in a range of 0.00001-0.1 mg per hour per gram of said soluble glass on the condition that the soluble glass has a particle size of 420-600 .mu.m and the water has a temperature of 20.degree. C. If the eluting rate is set to be less than 0.00001 mg per hour per gram, the antibacterial effect may become insufficient. On the other hand, an eluting rate exceeding 0.1 mg per hour per gram may make the duration of the antibacterial effect too short. A more preferable range is 0.0001-0.01 mg per hour per gram of said soluble glass on the condition that the soluble glass has a particle size of 420-600 .mu.m and the water has a temperature of 20.degree. C.

In the accompanying drawings:

FIG. 1 is a schematic illustration of a soluble glass particle containing Ag.sup.+ ions;

FIG. 2 is a schematic illustration of a soluble glass dissolving into water;

FIG. 3 is a schematic illustration explaining the zeolite particles supporting Ag.sup.+ as antibacterial ions in the pores;

FIG. 4 is a schematic illustration explaining the mechanism of Ag.sup.+ ion-discharge from zeolite particles;

Several examples of this invention will now be described.

A soluble glass containing Ag.sup.+ was prepared through the following procedure: 48 parts (in mol) of diphosphorous pentaoxide (P.sub.2 O.sub.5), 42 parts of calcium oxide (CaO) and 10 parts of aluminium oxide (Al.sub.2 O.sub.3) and 0.5 parts (in weight) of silver oxide (Ag.sub.2 O) were weighed and sufficiently mixed. The mixture was heated at 1300.degree. C. for 8-10 hr to form a molten glass. After cooling, the soluble glass was pulverized in a ball mill to form 2 .mu.m average sized particle. The particle size was measured using a laser forward scattering method (the same in the following example).

Components 1 and 2 described below were prepared respectively, and the Component 1 was molten at a designated temperature. Then the Component 1 was gradually emulsified into the Component 2 which had been preliminarily mixed thoroughly, thereby forming a soluble glass-based milky lotion. The Component 2 was prepared for two types, i.e., one of which contains 0.2 wt % of KOH, and the other of which contains no KOH.

A zeolite-based milky lotion was prepared using the following procedure: Y-type zeolite particles (1.14Na.sub.2 O.Al.sub.2 O.sub.3.4.9SiO.sub.2.xH.sub.2 O, average particle size 2.0 .mu.m) were immersed in an aqueous solution of 10 mol % of AgNO.sub.3, and then rinsed in water and subsequently dried. The Ag.sup.+ content supported on the particles was 3 wt %. A milky lotion was then prepared by using the zeolite particles instead of the soluble glass particles in the Component 2 according to a similar procedure.

As the first experiment, each milky lotions obtained were preserved in bottles for 6 month at ambient temperature in a dark place while the bottles were periodically opened once (for 10 minutes) per day, and after that, the solid component was filtered by a membrane filter from the lotions, and the Ag.sup.+ concentration was measured by using atomic absorption spectrochemical analysis for the residual liquids, respectively.

For the lotion using Component 2 containing no KOH, the resulting Ag.sup.+ concentration were 0.025 .mu.g/g for the soluble glass-based lotion and 0.004 .mu.g/g for the zeolite-based lotion. The liquid cosmetic base contains no alkaline-metal ion source, so that the eluting amount of Ag.sup.+ is very small for zeolite-based lotion, while the soluble glass-based lotion exhibited a value preferable for maintaining an antibacterial effect. On the other hand, for the lotion using Component 2 containing KOH, the Ag.sup.+ concentration for the zeolite-based lotion increased drastically to 0.045 .mu.g/g, while that for soluble glass-based lotion exhibited almost the same value.

As the second experiment, 0.1 g of the soluble glass-based and zeolite-based milky lotions (using Component 2 without containing KOH) obtained were added to 300 ml of physiological brine and held statically for 1 hr, respectively. Then, the soluble glass and zeolite particles in the brine were filtered by a membrane filter, and the Ag.sup.+ concentration was measured for the residual brine. The resulting value of Ag.sup.+ concentration was 0.001 .mu.g/g for the soluble glass-based lotion and 14.5 .mu.g/g for the zeolite-based lotion. The high Ag.sup.+ concentration for the zeolite-based lotion appears tribe due to the drastic chemical ion exchange reaction between Na.sup.+ and Ag.sup.+ ions. On the other hand, in the soluble glass-bases lotion, the Ag.sup.+ ions elute gradually along with the physical dissolution of soluble glass particles, so that the measured Ag.sup.+ concentration shows much smaller value than that for zeolite-based lotion.

A soluble glass containing Ag.sup.+ was prepared through the following procedure: 50 parts (in mol) of diphosphorous pentaoxide (P.sub.2 O.sub.5), 44 parts of magnesium oxide (MgO) and 6 parts of aluminium oxide (Al.sub.2 O.sub.3) and 1 parts (in weight) of silver oxide (Ag.sub.2 O) were weighed and sufficiently mixed. The mixture was heated at 1300.degree. C. for 8-10 hr to form a molten glass. After cooling, the soluble glass was pulverized in a ball mill to form 0.5 .mu.m average sized particle.

Components 1 and 2 described below were prepared respectively, and the Component 1 was molten at a designated temperature. Then the Component 1 was gradually emulsified into the Component 2 which had been preliminarily mixed thoroughly, thereby forming a soluble glass-based lotion. The Component 2 was prepared for two types, i.e., one of which contains 0.2 wt % of KOH, and the other of which contains no KOH.

A zeolite-based lotion was prepared using the following procedure: Y-type zeolite particles (1.14Na.sub.2 O.Al.sub.2 O.sub.3.4.9SiO.sub.2.xH.sub.2 O, average particle size 0.5 .mu.m) were immersed in an aqueous solution of 10 mol % of AgNO.sub.3, and then rinsed in water and subsequently dried. The Ag.sup.+ content supported on the particles was 3 wt %. A lotion was then prepared by using the zeolite particles instead of the soluble glass particles as contained in the Component 2 according to a similar procedure.

The first experiment was performed following the same procedure as that for Example 1. For the lotion using Component 2 containing no KOH, the resulting Ag.sup.+ concentration were 0.008 .mu.g/g for the soluble glass-based lotion and 0.002 .mu.g/g for the zeolite-based lotion. On the other hand, for the lotion using Component 2 containing KOH, the Ag.sup.+ concentration for the zeolite-based lotion increased drastically to 0.040 .mu.g/g while that for soluble glass-based lotion exhibited almost the same value.

The second experiment was also performed following the same procedure as that for Example 1. The resulting value of Ag.sup.+ concentration was 0.001 .mu.g/g for the soluble glass-based lotion and 14.0 .mu.g/g for the zeolite-based lotion.

Furthermore, as the third experiment, the soluble glass-based and zeolite-based lotions (using Component 2 containing KOH) were preserved for 6 month in colorless and transparent bottles, respectively, under exposure to light. The soluble glass-based lotion showed no change in appearance, but the zeolite-based lotion slightly turned black.

A soluble glass containing Ag.sup.+ was prepared through the following procedure: 92 parts (in weight) of magnesium hydropyrophosphate (MgH.sub.2 P.sub.2 O.sub.7), 15.3 parts of aluminum phosphate (AlPO.sub.4) and 1.47 parts of silver nitrate (AgNO.sub.3) were weighed and sufficiently mixed. The mixture was heated at 1300.degree. C. for 8-10 hr to form a molten glass. After cooling, the soluble glass obtained (chemical composition: P.sub.2 O.sub.5 =50 mol %, MgO=44 mol %, Al.sub.2 O.sub.3 =6 mol %, Ag.sub.2 O=1.0 wt %) was pulverized in a ball mill to form 2 .mu.m average sized particle.

Components 1-5 are described below. First, the Components 1 and 2 were mixed together in a Henschel type mixer, and then the Component 3 was sprayed onto the mixture of Components 1 and 2 under continuous mixing. The resultant mixture was crushed using an atomizer and then mixed with the Component 4. Finally, Component 5 was sufficiently dissolved into the resulting mixture, thereby forming a soluble glass-based liquid foundation. The Component 4 was prepared for two types, i.e, one of which contains 0.2 wt % of KOH, and the other of which contains no KOH.

A zeolite-based liquid foundation was prepared using the following procedure: Y-type zeolite particles (1.14Na.sub.2 O.Al.sub.2 O.sub.3.4.9SiO.sub.2.xH.sub.2 O, average particle size 2.0 .mu.m) were immersed in an aqueous solution of 10 mol % of AgNO.sub.3, and then rinsed in water and subsequently dried. The Ag.sup.+ content supported on the particles was 3 wt %. A liquid foundation was then prepared by using the zeolite particles instead of the soluble glass particles as the Component 2 according to a similar procedure.

The first experiment was performed following the same procedure as that for Example 1. For the liquid foundation using Component 4 containing no KOH, the resulting Ag.sup.+ concentration were 0.008 .mu.g/g for the soluble glass-based one and 0.001 .mu.g/g for the zeolite-based one. On the other hand, for the liquid foundation using Component 4 containing KOH, the Ag.sup.+ concentration for the zeolite-based one increased drastically to 0.038 .mu.g/g while that for soluble glass-based one exhibited almost the same value.

The second experiment was also performed following the same procedure as that for Example 1. The resulting value Ag.sup.+ concentration was 0.001 .mu.g/g for the soluble glass-based one and 13.8 .mu.g/g for the zeolite-based one.

A soluble glass containing Ag.sup.+ was prepared through the following procedure: 20 parts (in mol) of boric acid (B.sub.2 O.sub.3), 50 parts of silicon dioxide (SiO.sub.2) and 30 parts of sodium oxide (Na.sub.2 O) and 0.5 parts (in weight) of silver oxide (Ag.sub.2 O) were weighed and sufficiently mixed. The mixture was heated at 1300.degree. C. for 8-10 hr to form a molten glass. After cooling, the soluble glass was pulverized in a ball mill to form 2 .mu.m average sized particle.

By using following Components 1-5, a soluble glass-based liquid foundation was prepared according to the same procedure as that for example 2. The Component 5 was prepared for two types, i.e, one of which contains 0.2 wt % of KOH, and the other of which contains no KOH.

On the other hand, the same zeolite-based liquid foundation as that for example 2 was prepared as a reference sample.

The first experiment was performed following the same procedure as that for Example 1. For the liquid foundation using Component 5 containing no KOH, the resulting Ag.sup.+ concentration were 0.018 .mu.g/g for the soluble glass-based one and 0.001 .mu.g/g for the zeolite-based one. In the other hand, for the liquid foundation using Component 5 containing KOH, the Ag.sup.+ concentration for the zeolite-based one increased drastically to 0.055 .mu.g/g while that for soluble glass-based one exhibited almost the same value.

The second experiment was also performed following the same procedure as that for Example 1. The resulting value Ag.sup.+ concentration was 0.001 .mu.g/g for the soluble glass-based one and 14.3 .mu.g/g for the zeolite-based one.

A liquid foundation composed of the following Components 1 to 5 was prepared.

The silver ion containing soluble glass of the Component 2 has the following conditions;

Theoretical glass composition:

P.sub.2 O.sub.5 50 mol %; MgO 44 mol %; Al.sub.2 O.sub.3 6 mol %; Ag.sub.2 O 1.0 wt %;

Dissolving speed:

0.0003 mg/g/Hr (silver ion eluting amount in water at 20.degree. C. in a glass particle size of 425-600 .mu.m);

Particle size: 5 .mu.m or less.

The Components 1 and 2 were mixed together by using a Henschel mixer, and the Component 3 was sprayed to the mixture thus obtained to carry 6out further mixing. Then, the mixture was pulverized by using an atomizer.

The Component 4 was added to the Component 5 to carry out sufficient mixing. Then, the mixture of the Components 1, 2 and 3 was added to the mixture of the Components 4 and 5 to carry out uniform mixing, thereby obtaining the objective liquid foundation.

The talc used was unsterilized, and a standard plate count of bacteria and a mold count of the liquid foundation and the talc used were measured. The results of measurement are shown in Table 1.

This liquid foundation was used with a puff twice a day under an ordinary condition, and the standard plate count of bacteria and the mold count were measured after six months. As the result, both the standard plate count and the mold count of the liquid foundation in Example 5 were negative, and no problems occurred.

A liquid foundation composed of the following Components 1 to 5 was prepared.

The copper ion containing soluble glass of the Component 2 has the following conditions;

Theoretical glass composition:

P.sub.2 O.sub.5 50 mol %; K.sub.2 O 20 mol %; CaO 15 mol %; CuO 5.0 mol %;

Dissolving speed:

0.002 mg/g/Hr (copper ion eluting amount in water at 20.degree. C. in a glass particle size of 425-600 .mu.m);

Particle size: 10 .mu.m or less.

The Components 1 and 2 were mixed together by using a Henschel mixer, and the Component 3 was sprayed to the mixture thus obtained to carry out further mixing. Then, the mixture was pulverized by using an atomizer.

The Component 4 was added to the Component 5 to carry out sufficient mixing. Then, the mixture of the Components 1, 2 and 3 was added to the mixture of the Components 4 and 5 to carry out uniform mixing, thereby obtaining the objective liquid foundation.

The talc used was unsterilized, and a standard plate count of bacteria and a mold count of the liquid foundation and the talc used were measured. The results of measurement are shown in Table 2.

This liquid foundation was used with a puff twice a day under an ordinary condition, and the standard plate count of bacteria and the mold count were measured after six months. As the result, both the standard plate count and the mold count of the liquid foundation in Example 6 were negative, and no problems occurred.