WO2014156805A1

WO2014156805A1 - Magnetic powder for cosmetic agent

Info

Publication number: WO2014156805A1
Application number: PCT/JP2014/057248
Authority: WO
Inventors: 松下　剛; 弘道小林
Original assignee: 株式会社Ｍｔｇ; パウダーテック株式会社
Priority date: 2013-03-29
Filing date: 2014-03-18
Publication date: 2014-10-02
Also published as: JP6363063B2; CN105188640A; JPWO2014156805A1; TW201517926A; TWI627969B

Abstract

A magnetic powder for cosmetic agents, configured so as to be capable of being adsorbed and removed by magnetic force from a cosmetic agent applied to the face. The magnetic powder for cosmetic agents has a magnetite content of at least 80% by mass, the remaining content being wüstite, hematite, and unavoidable impurities. The volume average particle diameter found using the particle distribution obtained by the laser diffraction scattering method is 50-75 µm. The magnetic powder contains no more than 15% by mass particles having a particle diameter of less than 37 µm and contains no more than 5% by mass particles having a particle diameter of at least 105 µm.

Description

Magnetic powder for beauty agents

The present invention relates to a magnetic powder for a cosmetic used in a cosmetic applied to the skin.

There is a paste-like beauty agent used for skin beautification, which removes dirt and waste from the skin together with the beauty agent by removing it after a while after being applied to the skin. Such cosmetics are roughly classified into those that form a film when time passes after application and those that maintain a paste state even after time.

A cosmetic agent that becomes a film after application can be easily separated from the skin by grasping and peeling off a part thereof. On the other hand, as a method of removing from the skin what remains in the paste state even after application, a method of wiping with cotton or the like, or washing off with warm water or the like is common. Recently, there has been a demand for a method for removing a cosmetic after use more easily than these general methods.

For example, Patent Document 1 proposes a method in which a cosmetic agent mixed with iron powder and a remover provided with a magnet in the main body are used in combination. In this way, by using a beauty agent mixed with iron powder and a remover equipped with a magnet, the used beauty agent applied to the skin can be easily removed by magnetic force, and dirt and waste on the skin can be removed. Can be removed together with iron powder in cosmetics.

Patent Documents 2 to 3 disclose examples of beauty agents that can be adsorbed and removed from the skin by magnetic force. These cosmetics are made by mixing iron powder or iron oxide with a cream-like base material containing nutritional components and the like. After the cosmetics are adsorbed and removed, the nutritional components remain on the skin surface. I am trying. Thereby, it is going to exhibit two effects, the effect | action which removes the stain | pollution | contamination of skin, etc. and the effect | action which gives a nutrient component etc. to skin.

JP 2004-187874 A JP 2004-155720 A JP 2005-239563 A

However, conventional cosmetics containing magnetic powder may not be sufficiently adsorbed and removed from the skin, and magnetic powder that has not been adsorbed to the remover may remain on the skin surface. In this case, it is necessary to separately wash the face in order to remove the magnetic powder remaining on the skin, which is inconvenient for the user.

Also, when iron powder is used as the magnetic powder, the iron powder is easily oxidized after being mixed with the beauty agent, and the magnetic characteristics and color tone are likely to change. Therefore, there has been a problem that the performance of the beauty agent is likely to vary. Moreover, since magnetic characteristics and color tone change with the oxidation of iron powder, there was a problem that long-term storage is difficult. This problem cannot be sufficiently solved even when iron powder is coated as in Patent Document 2.

When iron oxide is used as the magnetic powder, the above-described problems caused by the oxidation of the iron powder can be solved to some extent. However, in this case, the reddish brown hematite (Fe ₂ O ₃ ) contained in the iron oxide makes the beauty agent mixed with magnetic powder reddish, so it is difficult to achieve a color tone that is preferable as a beauty agent. It was.

Thus, there is still room for improvement in cosmetics that are adsorbed and removed from the skin by magnetic force, and it cannot be said that optimum conditions have been found for magnetic powders to be mixed with cosmetics.

The present invention has been made in view of such a background, and an object of the present invention is to provide an optimal magnetic powder for a cosmetic agent that can be adsorbed and removed from the cosmetic agent applied to the skin.

One aspect of the present invention is a magnetic powder for cosmetics configured to be adsorbed and removed from a cosmetic applied to the skin,
The magnetite content is 80% by mass or more, and the balance consists of wustite, hematite and inevitable impurities,
The volume average particle size obtained from the particle size distribution obtained by the laser diffraction scattering method is 50 to 75 μm,
A magnetic powder for a cosmetic agent, wherein the content of particles having a particle size of less than 37 μm is 15% by mass or less and the content of particles having a particle size of 105 μm or more is 5% by mass or less. is there.

The magnetic powder for cosmetics is made of iron oxide. Therefore, after mixing with a beauty agent, it is hard to receive further oxidation, and the beauty agent which mixed the said magnetic powder for beauty agents becomes easy to suppress the dispersion | variation in performance. In addition, since the magnetic properties and color tone are less likely to change, the above-described beauty agent has a small change in performance even when stored for a long time.

Further, the magnetic powder for cosmetics controls both the ratio of chemical components contained therein and the particle size distribution within the specific range. Thus, by finely controlling both the chemical composition and the particle size distribution of the magnetic powder, both the ease of adsorption of the magnetic powder for cosmetics from the skin and the good touch when touching the skin are achieved. It can be optimized at the same time, and the phenomenon of redness of the cosmetic can be suppressed.

That is, the magnetite content ratio is set to the specified value or more, and the volume average particle size of the magnetic powder for cosmetics is controlled to 50 μm or more, and the content of the small-sized particles is further set to the specified amount or less. By regulating, the magnetic force acting on the entire magnetic powder for beauty agent can be increased. As a result, the user can efficiently adsorb and remove the magnetic powder for cosmetics from the skin. Moreover, since the said magnetic powder for cosmetics is hard to remain on the skin surface, it is not necessary to separately wash the face for removing the magnetic powder for cosmetics, and the convenience for the user can be improved.

Furthermore, by increasing the content ratio of the magnetite and controlling the content of the volume average particle size and the small particle size as described above, it is possible to effectively suppress the influence of hematite on the color tone of the cosmetic agent. As a result, it is possible to effectively suppress the phenomenon that the beauty agent is reddish, and toning the beauty agent can be performed more easily.

In addition, by controlling the volume average particle size of the magnetic powder for cosmetics to 75 μm or less, and further regulating the content of the large particles to the specific amount or less, the magnetic powder for cosmetics is Roughness at the time of contact with the skin can be reduced. As a result, the beauty agent using the magnetic powder for beauty agent exhibits a smooth touch.

As described above, the magnetic powder for cosmetics has optimum characteristics for inclusion in cosmetics that are adsorbed and removed from the skin.

Explanatory drawing of the usage method of a cosmetic agent in an Example.

The magnetic powder for beauty agent is used by being mixed with a fluid beauty agent such as paste or liquid. The beauty agent contains various beauty components, and is configured to have a beauty effect such as replenishing nutrients to the skin or raising the dirt component of the skin. Further, the cosmetic agent may be configured so that at least a part thereof remains on the skin surface when the magnetic powder for cosmetic agent is adsorbed and removed from the skin by a magnetic force according to the beauty effect to be obtained. The magnetic powder for beauty agent may be configured so that almost all is removed from the skin surface.

It said cosmetic agent for the magnetic powder, magnetite _(Fe _{3 O} 4), hematite _(Fe _{2 O} 3), has a composition consisting of wustite (FeO) and incidental impurities. Among these, magnetite is a ferromagnetic material having ferrimagnetism, but hematite and wustite are antiferromagnetic materials. Therefore, by increasing the content of magnetite, a large magnetic force can be applied to the entire magnetic powder for beauty agent, and the adsorption removal of the beauty agent can be performed more efficiently. Moreover, since hematite exhibits a reddish brown color, it is possible to suppress the phenomenon that the cosmetic agent is reddish by reducing the content thereof. As described above, not only the control of chemical components but also the fine control of the particle size distribution allows these effects to be exhibited more reliably.

The volume average particle diameter can be calculated as the cumulative 50% particle diameter (median diameter) obtained by the volume distribution mode and display under the sieve in the particle diameter distribution obtained by the laser diffraction scattering method.

The content of particles having a particle size of less than 37 μm (hereinafter sometimes referred to as “small particle”) is measured, for example, as the amount of particles that can pass through a standard sieve having a nominal size of 37 μm (400 mesh). Can do.

The content of particles having a particle size of 105 μm or more (hereinafter sometimes referred to as “large particle”) is measured, for example, as the amount of particles that cannot pass through a standard sieve having a nominal size of 105 μm (145 mesh). be able to.

When the volume average particle size is less than 50 μm, the particle size distribution tends to have a large content of particles having an excessively small particle size. The magnetic force acting on individual particles becomes weaker as the particle size is smaller. Therefore, when many particles having an excessively small particle size are contained, the magnetic force acting on the entire beauty powder magnetic powder tends to be weakened, and the beauty powder magnetic powder may be difficult to be adsorbed and removed from the skin.

In addition, when a large amount of particles having an excessively small particle size is contained, a phenomenon in which the beauty agent becomes reddish easily occurs when mixed with the beauty agent. Although this mechanism is not clear at the present time, it is considered that hematite reddish brown greatly affects the color tone of the cosmetic agent due to an increase in particles having an excessively small particle size.

However, it is difficult to reliably reduce the content of particles having an excessively small particle size only by controlling the volume average particle size to 50 μm or more. Therefore, in addition to controlling the volume average particle size to 50 μm or more, as described above, it is important to regulate the content of small-diameter particles to 15% by mass or less. By restricting the content of small-diameter particles to 15% by mass or less, the content of particles having an excessively small particle size can be reliably reduced.

On the other hand, when the volume average particle size exceeds 75 μm, the particle size distribution has a large content of particles having an excessively large particle size. Therefore, in this case, there is a possibility that the feeling of use is deteriorated, for example, the feel of the beauty agent mixed with the magnetic powder for beauty agent becomes worse.

However, it is difficult to reliably reduce the content of particles having an excessively large particle size only by controlling the volume average particle size to 75 μm or less. Therefore, in addition to controlling the volume average particle size to 75 μm or less, it is important to regulate the content of large particles to 5% by mass or less as described above. By regulating the content of large-diameter particles to 5% by mass or less, the content of particles having an excessively large particle size can be reliably reduced.

As described above, the volume average particle diameter of the magnetic powder for cosmetics is controlled within the above specific range, and further, by controlling both the content of the small particle and the content of the large particle, an appropriate size can be obtained. An optimal particle size distribution with an increased content of particles can be realized. Then, by finely controlling the particle size distribution as described above, by controlling the chemical component, the magnetic powder for cosmetics exhibits optimum characteristics for inclusion in the cosmetic.

Further, the magnetic powder for cosmetics preferably has a hematite content of 5% by mass or less. In this case, since the ratio of the diamagnetic substance in the magnetic powder for cosmetics is reduced, it becomes easier to increase the magnetic force acting on the entire magnetic powder for cosmetics, and the adsorption and removal of the magnetic powder for cosmetics is more efficient. Can be done automatically. Moreover, since the content of red-brown hematite is reduced, it is possible to more reliably suppress the phenomenon that the cosmetic agent is reddish.

Further, it is preferable that the transmittance at a wavelength of 474 nm of the supernatant obtained by dispersing the magnetic powder for cosmetics in methanol is 90% or more. The transmittance of the supernatant liquid is mainly composed of hematite, and is used as a value indicating the content of particles having a particle size that is extremely small enough to disperse in methanol.

When the transmittance is 90% or more, it is possible to sufficiently reduce the content of the above-described particles having a very small particle diameter. Such particles having a very small particle size are not preferable because they are reduced in the adsorption and removal efficiency of the magnetic powder for cosmetics and cause the cosmetics to be reddish. In addition, the smaller the particle size, the easier it is to deteriorate the performance of the cosmetic magnetic powder. Therefore, by controlling the transmittance of the supernatant liquid as an index and controlling the value within the above specific range, it is possible to further improve the adsorption removal efficiency of the magnetic powder for cosmetics, and the phenomenon that the cosmetics become reddish. It can suppress more reliably.

Further, the content of wustite is preferably 15% by mass or less. In this case, since the ratio of the diamagnetic substance in the magnetic powder for beauty agent is reduced, the magnetic force acting on the entire magnetic powder for beauty agent can be made stronger. As a result, it is possible to more efficiently adsorb and remove the magnetic powder for cosmetics. In addition, since wustite has a lower degree of oxidation than magnetite and the like, reducing the wustite content makes the magnetic powder for cosmetics less susceptible to further oxidation. As a result, the performance of the magnetic powder for beauty agents can be stabilized for a longer period of time.

Moreover, it is preferable that the magnetic powder for beauty agents has a saturation magnetization of 80 Am ² / kg or more. In this case, the magnetization of the magnetic powder for beauty agent can be sufficiently increased, and the magnetic force acting on the magnetic powder for beauty agent can be further increased. As a result, the magnetic powder for cosmetics can perform adsorption removal from the skin more efficiently.

The cosmetic magnetic powder preferably has an apparent density of 1.95 to 2.65 g / cm ³ .

The apparent density of the magnetic powder for beauty agents is a value used as an index of the average shape of the particles constituting the magnetic powder for beauty agents. The higher the apparent density, the more the average shape of the particles becomes a true sphere. Indicates approaching. That is, the magnetic powder for cosmetics having a high apparent density tends to be substantially spherical and contain many particles with relatively small irregularities. On the other hand, the magnetic powder for cosmetics with a low apparent density tends to be non-spherical, such as an approximately ellipsoidal shape or a lump shape, and contains many particles with relatively large irregularities.

Moreover, the magnetic powder for cosmetics having a high apparent density tends to have a larger mass of individual particles than the magnetic powder for cosmetics having a low apparent density. Therefore, the magnetic force which acts on the whole magnetic powder for beauty agents tends to become large. As this cause, for example, when the apparent density is increased, the volume of the cavity existing inside the particle is decreased.

When the apparent density of the magnetic powder for beauty agents exceeds 2.65 g / cm ³ , the content of excessively large particles may increase. Therefore, there is a possibility that it is difficult to disperse uniformly in a state of being mixed with a cosmetic agent. In some cases, the magnetic powder for cosmetic agent may be precipitated during storage.

On the other hand, when the apparent density is less than 1.95 g / cm ³ , the uneven shape of the particles may become excessively large. Thereby, there is a possibility that the viscosity of the beauty agent may be increased, and in some cases, it may be difficult to apply to the skin.

When the apparent density is less than 1.95 g / cm ³ , there are two possibilities: the possibility that the crystal growth of the particles is insufficient and the possibility that the crystal growth of the particles proceeds excessively. If the crystal growth of the particles is insufficient, the unevenness may become excessively large as described above, and the strength of the particles may be reduced. Chipping may occur. Such an excessively large uneven shape or generation of cracks or chipping of the particles is not preferable because it causes the touch to deteriorate and the magnetic force acting on the particles decreases.

Further, when the crystal growth of the particles proceeds excessively, the particles are likely to be fused excessively, and the unevenness of the particles may be excessively increased by the fusion as described above. Further, along with this, when the fused particles are crushed, the unevenness of the particles generated by the pulverization may become excessively large. Therefore, in this case, the ease of spreading when applying the cosmetic agent to the skin may be deteriorated, or the touch when applying the beauty agent may be deteriorated.

The beauty powder magnetic powder preferably has a specific surface area of 200 to 450 cm ² / g as measured using an air permeation method. The specific surface area of the magnetic powder for beauty agent is an index of the fine structure such as pores formed on the surface of the particles, and the larger the specific surface area value, the more pores and the like are formed.

When the specific surface area of the magnetic powder for beauty agents is less than 200 cm ² / g, there is a possibility that fine structures such as pores are not sufficiently formed. Therefore, it is difficult for the cosmetic agent to be held on the surface of the particles, and it may be difficult to disperse in the cosmetic agent. On the other hand, when the specific surface area of the magnetic powder for cosmetic agent exceeds 450 cm ² / g, the fine structure may be excessively formed, and the cosmetic component may enter the fine structure. Therefore, the amount of cosmetic ingredients that can act directly on the skin is reduced, and the cosmetic effect may be reduced.

The magnetic powder for beauty agent may be configured such that the magnetic powder for beauty agent can exhibit another function by a technique such as binding a cosmetic ingredient to the surface or applying a coating. Examples of functions to be applied to the magnetic powder for beauty agents include improving the dispersibility of the magnetic powder for beauty agents using a surfactant, etc., and using the magnetic powder for beauty agents using a resin component that adsorbs sebum For example, it is possible to absorb and remove sebum from the skin.

As described above, when the surface of the magnetic powder for cosmetics is modified with a surface modifier such as a coating agent, it is preferable that the magnetic powder for cosmetics contains a large number of particles with an appropriately large uneven shape. . Particles having a reasonably large uneven shape have a larger surface area than when the uneven shape is small, so that it is easy to retain the surface modifier. Therefore, the magnetic powder for cosmetics containing a large amount of such particles can more easily obtain the effect of surface modification by the surface modifier. On the other hand, when a large amount of particles such as a substantially spherical shape having a small concavo-convex shape are contained, the surface modifier is difficult to adhere to the individual particles, which may make it difficult to obtain the effect of surface modification.

In order to make it easier to obtain the effect of the surface modifier, the apparent density is preferably 1.95 to 2.65 g / cm ³ , and the specific surface area as measured by the air permeation method is 200 to 200 450cm is preferably ² / g. If either one of the values of the apparent density and the specific surface area is in the above specific range, it is easy to obtain the surface modification effect, and if both satisfy the above specific range, the surface modification effect can be further obtained. It becomes easy.

Note that the magnetic powder for cosmetics contains inevitable impurities derived from raw materials and manufacturing processes in addition to magnetite, hematite, and wustite. Inevitable impurities include, for example, lead and arsenic, but their content is usually regulated to lead: 40 ppm or less and arsenic: 10 ppm or less.

Next, a method for producing the magnetic powder for cosmetics will be described. As a method for producing the magnetic powder for beauty agent, a conventionally known method can be employed. As one aspect of the manufacturing method of the magnetic powder for beauty agents, after pulverizing and mixing the predetermined raw materials and auxiliary raw materials, granulation, firing the obtained granulated product, further crush the granulated product, A method for performing classification treatment is mentioned.

As a raw material for the magnetic powder for beauty agents, magnetite collected from natural ores including magnetite, iron oxide manufactured industrially, and the like can be used.

Further, magnetite may be used as the raw material obtained by reducing the industrially produced hematite (Fe 2 _O _3). When hematite is reduced, the purity and chemical components of the obtained magnetite can be easily adjusted. As a result, the quality of the magnetic powder for beauty agents can be more easily stabilized.

For example, hematite is reduced to magnetite by heating in a state where it coexists with a carbon component. This reaction theoretically follows the following reaction formula.
6Fe ₂ O ₃ + C → 4Fe ₃ O ₄ + CO ₂
Therefore, in order to completely reduce hematite to magnetite, at least 1.25 parts by mass of carbon is required for 100 parts by mass of hematite. Under actual production conditions, hematite may not be completely reduced by blending according to the above reaction formula, so it is preferable to blend more than 1.25 parts by mass of carbon.

The method of preparing the granulated product from the pulverized and mixed raw materials may be a dry method or a wet method. When the wet method is used, for example, the raw material and water are mixed and pulverized with a ball mill or the like, and then a dispersant, a binder or the like is added as necessary to adjust the viscosity to obtain a slurry-like mixture. Thereafter, the mixture can be granulated using a spray dryer. In this case, it is preferable to use polyvinyl alcohol or polyvinyl pyrrolidone as the binder.

Moreover, the granulated product is usually fired by heating at a temperature of 1100 to 1400 ° C. for 1 to 24 hours. As the furnace used for firing, a known furnace such as a rotary electric furnace, a batch electric furnace, a tunnel electric furnace, or the like can be used. Further, the atmosphere during firing can be appropriately selected in consideration of the target degree of oxidation and magnetic characteristics.

As a method of classifying the baked product obtained by calcination after pulverization, a known method such as air classification, mesh filtration, or sedimentation can be used. When performing dry recovery, it is also possible to recover with a cyclone or the like. It is also possible to combine a plurality of these classification methods. By performing the classification process using these methods, the particle size distribution of the magnetic powder for beauty agents can be adjusted to a desired distribution.

In addition, before or after the classification process, magnetic separation may be performed as necessary. By performing magnetic separation, particles having a low magnetic susceptibility can be removed.

Examples of the magnetic powder for cosmetics will be described below. The magnetic powder for cosmetics of this example is formed from magnetite exhibiting ferromagnetism. Further, as shown in Table 1, the magnetic powder for cosmetics of this example has a volume average particle size determined from the particle size distribution obtained by the laser diffraction scattering method of 50 to 75 μm and a particle size of less than 37 μm. The content of a certain particle (small particle) is 15% by mass or less, and the content of a particle (large particle) having a particle size of 105 μm or more is 5% by mass or less.

The magnetic powder for beauty agent is used by being mixed with a paste-like beauty agent 1 applied to the skin as shown in FIG. The cosmetic agent 1 of this example is configured such that after the magnetic powder for cosmetic agent is adsorbed and removed from the skin by the magnetic force generated from the magnetic force generating surface 20 of the remover 2, the cosmetic components remain on the skin surface.

In this example, various cosmetic magnetic powders (samples No. 1 to No. 15) shown in Table 1 were prepared by the following manufacturing method.

<Method for producing magnetic powder for beauty agent mainly composed of magnetite>
Water was added to the powder obtained by pulverizing hematite (Fe ₂ O ₃ ) so that the solid content was 55% by mass to prepare a slurry. Next, after adding 1% by weight of polyvinyl alcohol, 0.9% by weight of carbon black, and 0.5% by weight of polycarboxylate salt to the solid content of the obtained slurry, this mixture was added. Water was added to the slurry to prepare a slurry having a solid content of 55% by mass. Subsequently, the slurry obtained using an attritor was stirred for 1 hour. Thereafter, the slurry was granulated into a spherical shape using a spray dryer, and the particle size of the granulated product obtained using a gyro shifter was adjusted.

Then, the spherical granulated product whose particle size was adjusted was heated at 1320 ° C. for 3 hours to reduce the raw material hematite, and a fired product containing magnetite as a main component was obtained. The granulated product was heated in a nitrogen atmosphere using a tunnel electric furnace.

After the obtained fired product was crushed, a classification treatment was performed by using a combination of a gyro shifter and an air classifier to adjust the particle size distribution. Thereafter, magnetic separation was carried out to select particles having a high magnetic susceptibility, and a magnetic powder for cosmetics (sample No. 1) containing magnetite as a main component was obtained.

Sample No. In the production method of No. 1, sample No. 1 was changed by appropriately changing the amount of carbon black to be added, heating conditions, and classification conditions. 2 to No. 13 was obtained.

<Method for Producing Magnetic Powder for Beauty Agent with Mn Ferrite as Main Component>
Hematite and trimanganese tetroxide were weighed so as to be MnO: 20 mol% and Fe ₂ O ₃ : 80 mol%, and pulverized with a wet media mill for 1 hour to obtain a slurry. The obtained slurry was dried with a spray dryer to obtain a spherical granulated product. Subsequently, after adjusting the particle size of the granulated product obtained using a gyro shifter, it was calcined by heating at 950 ° C. for 2 hours.

Thereafter, water was added to the granulated product after the preliminary firing so that the solid content was 55% by mass, and then pulverized and mixed for 1 hour using an attritor to prepare a slurry. Furthermore, 2 mass% polyvinyl alcohol and an appropriate amount of a dispersant were added to the solid content of the obtained slurry. Thereafter, the slurry was granulated into a spherical shape with a spray dryer, and the particle size was adjusted using a gyro shifter.

Subsequently, the spherical granulated product whose particle size was adjusted was heated at 1310 ° C. for 3 hours to react hematite and trimanganese tetroxide to obtain a fired product mainly composed of Mn ferrite. The granulated product was heated in a nitrogen atmosphere using a tunnel electric furnace.

After the obtained fired product was crushed, a classification treatment was performed by using a combination of a gyro shifter and an air classifier to adjust the particle size distribution. Thereafter, magnetic separation was carried out to select particles having a high magnetic susceptibility, and a magnetic powder for cosmetics (sample No. 15) mainly composed of Mn ferrite was obtained.

Sample No. As for No. 14, commercially available spherical iron powder having a volume average particle diameter of about 80 μm was used.

Using the samples obtained by the above method, various characteristics were evaluated by the following methods.

<Volume average particle diameter>
After adding 0.2% sodium hexametaphosphate aqueous solution to the sample, ultrasonic treatment is performed for 1 minute using an ultrasonic homogenizer (UH-3C, manufactured by Ultrasonic Industry Co., Ltd.) to obtain a magnetic powder dispersion for cosmetics. Prepared. This dispersion was introduced into a Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd., Model 9320-X100) and measured under conditions of a refractive index of 1.81, a temperature of 25 ± 5 ° C., and a humidity of 55 ± 15%, and laser diffraction. The particle size distribution by the scattering method was obtained. From the obtained particle size distribution, the 50% cumulative particle size in the volume distribution mode and under the sieve display was calculated, and this was defined as the volume average particle size (median diameter).

<Content of small particle and content of large particle>
Using a standard sieve defined in JIS Z 8801, the samples were classified by a method according to JIS H 2601. Thereby, the content of particles (small particle) that passed through a standard sieve having a nominal size of 37 μm (400 mesh) and the content of particles (large particle) that did not pass through the standard sieve having a nominal size of 105 μm (145 mesh) were obtained. It was measured.

<Apparent density>
In accordance with the apparent density test method for metal powder specified in JIS Z 2504, measurement was performed by the following method. As an apparent density measuring device, a device comprising a funnel, a cup, a funnel support, a support bar and a support base having an orifice with a pore diameter of 2.5 ^{+ 0.2 / 0} mm was used. First, at least 150 g of sample was poured into the funnel and the sample flowing out of the funnel was poured directly into a cup placed under the funnel. After the cup was filled with the sample, the sample flow was stopped immediately when the sample overflowed from the cup.

Next, a horizontal spatula formed of a nonmagnetic material was moved horizontally along the opening surface of the cup, and the sample raised on the cup was scraped off. Thereafter, the side of the cup was lightly tapped to stabilize the sample, and the sample adhering to the side of the cup was wiped off, and then the weight of the sample in the cup was weighed using a balance having a weight of 200 g and a sensitivity of 50 mg. The value obtained by multiplying the obtained weight value by 0.04 and rounding this value to the second decimal place using the rounding method defined in JIS Z 8401 is the apparent density (g / cm ³ ). did.

<Saturation magnetization, residual magnetization and coercivity>
Measurement was carried out by the following procedure using an integral type BH tracer (manufactured by Riken Denshi Co., Ltd., BHU-60 type). First, an H coil for magnetic field measurement and a 4πI coil for magnetization measurement are placed between electromagnets, and a sample is placed in the 4πI coil. Next, the output of the H coil and the 4πI coil whose magnetic field H is changed by changing the current of the electromagnet is integrated, the H output is taken on the X axis, and the hysteresis loop taking the output of the 4πI coil on the Y axis is applied to the recording paper. Draw. Saturation magnetization, residual magnetization and coercive force were read from this hysteresis loop. Saturation magnetization, residual magnetization, and coercive force were measured by filling a cell having an inner diameter of 7 mmφ ± 0.02 mm and a height of 10 mm ± 0.1 mm with a sample of about 1 g, 4πI coil: 30 turns, applied magnetic field: 3000 oersted. Performed under conditions.

<Supernatant transmittance>
A 15 g sample was weighed and placed in a 50 ml sample bottle. After adding 20 ml of methanol to the sample bottle and capping, the sample bottle was stirred at 150 rpm for 20 minutes using a rotary stirrer. After the stirring was completed, a sample was adsorbed by bringing a magnet into contact with the bottom of the sample bottle, and in this state, the sample bottle was shaken three times by hand. Thereafter, 3 ml of the supernatant of the sample bottle was collected, and the transmittance of the supernatant at a wavelength of 474 nm was measured using a visible spectrophotometer (Ogawa Seiki, Model 6100). In addition, methanol was used as a blank sample in the transmittance measurement.

<Specific surface area>
After filling the sample into a plastic sample tube, the specific surface area was measured by an air permeation method using a powder specific surface area measuring device (SS-100 model, manufactured by Shimadzu Corporation). A more specific sample filling method and measurement procedure are as follows.

(1) Filling of sample A sieve plate was placed in a plastic sample tube, and a filter paper was further laid on the sieve plate, and the sample tube was placed on a tap stand of a powder tester (manufactured by Hosokawa Micron). Next, the sample was poured into about 1/3 of the sample tube, the powder tester was activated, and the sample tube was tapped for 60 seconds. After tapping, the sample was poured to about 2/3 of the sample tube, the powder tester was operated again, and the sample tube was tapped for 60 seconds. Thereafter, the sample was added until the sample tube was filled, the powder tester was operated, and the sample tube was tapped for 60 seconds. After the third tap was completed, the excess sample adhering to the sample tube was removed using a brush, a wiper or the like, and the sample filling was completed.

(2) Measurement of specific surface area Vaseline was applied to the lower part of the sample tube, and after connecting this part to the measurement tube, pure water was injected into the measurement tube. Next, the cock at the lower outlet of the measuring device was opened to allow pure water to flow out of the measuring tube, and the time t until the water level in the measuring tube decreased by 20 cc was measured. The time t (sec) required for 20 cc of air thus obtained to permeate the sample packed bed and the weight W (g) of the sample filled in the sample tube are expressed by the Kozeny-Carman equation (the following equation (1) The specific surface area Sw of the sample was determined.

Here, ε in the equation (1) is the porosity of the sample packed layer obtained by the following equation (2).

The meanings of the other symbols in the above formulas (1) and (2) are as follows.
Specific surface area of sample: Sw (cm ² / g)
Sample density: ρ (g / cm ³ )
Air viscosity coefficient: η (g / cm · sec)
Sample packed layer thickness: L (cm)
Volume of air that has passed through the sample packed bed: Q (cc)
Pressure difference between both ends of sample packed bed: ΔP (g / cm ² )
Cross-sectional area of sample packed layer: A (cm ² )

<Magnetite composition ratio>
For cosmetic agent magnetic powder mainly composed of magnetite, magnetite by X-ray diffraction method _(Fe _{3 O} 4), the composition ratio of hematite _(Fe 2 _{O 3)} and wustite (FeO) was calculated by the following method.

“X'PertPRO MPD” manufactured by Panalical Co., Ltd. was used as a measuring apparatus. Measurement was performed by continuous scanning at 0.2 ° / sec using a Co tube (CoKα ray) as an X-ray source and a concentrated optical system and a high-speed detector “X′Celarator” as an optical system. Analysis of the measurement results is performed in the same way as ordinary powder crystal structure analysis using the analysis software “X'PertHighScore”. After identifying the crystal structure, the obtained crystal structure is refined and converted to weight. The abundance ratio was calculated. In calculating the abundance ratio, the abundance ratios of magnetite, hematite, and wustite were calculated using Fe and O as essential elements.

The X-ray source used for X-ray diffraction measurement can be measured without problems even with a Cu tube, but in the case of a sample containing a large amount of Fe, the background becomes larger than the peak to be measured, so the Co tube Is preferred. Further, the optical system may obtain the same result even when the parallel method is used. However, since the X-ray intensity is low and the measurement takes time, the measurement with the concentrated optical system is preferable. Further, the speed of the continuous scan is not particularly limited, but in order to obtain a sufficient S / N ratio when analyzing the crystal structure, the peak intensity of the (311) plane which is the main peak of magnetite is set to 50000 cps or more. The measurement was performed by setting the sample in the sample cell so that the particles were not oriented in a specific preferred direction.

Table 1 shows various properties of the magnetic powder for cosmetics evaluated by the above methods.

Next, the characteristics of the beauty agent mixed with the magnetic powder for beauty agent were evaluated by the following method.

In addition, the cosmetics which have the following compositions were used for the said characteristic evaluation.
-Magnetic powder for beauty agents 60.0% by mass
・ Glycerin 20.0% by mass
・ Methylparaben 0.38% by mass
・ Decamethylcyclopentasiloxane 1.3% by mass
・ Trioctylglyceryl 3.8% by mass
・ Cetyl 2-ethylhexanoate 3.8% by mass
・ Bentonite 0.19% by mass
・ Polyoxyethylene / methylpolysiloxane copolymer 2.25% by mass
・ Polyglyceryl monolaurate 0.25% by mass
-Sodium polyacrylate 0.01% by mass
・ Sodium hydroxide 0.03% by mass
・ Sodium ascorbate 0.13 mass%
・ Perfume 0.13 mass%
・ Water balance

<Adsorption removal>
A beauty agent mixed with magnetic powder for beauty agent was applied to a flat plate placed on a horizontal surface. The height from the flat plate to the test head when the magnetic powder for cosmetics was adsorbed on the test head was measured from the top of the cosmetic applied with the test head containing the neodymium magnet. It is shown in the column of “Adsorption distance”. The value described in Table 2 indicates that the larger the magnetic powder for cosmetic agent is, the easier it is to remove by adsorption. The neodymium magnet built in the test head was a cylinder with a diameter of about 25 mm and a height of about 8 mm, and the surface magnetic flux density of the magnet alone was 266 mT. Further, a 2 mm-thick yoke material having a disk shape was disposed on the end face facing upward of the neodymium magnet.

<Feel>
The feel when the cosmetic agent was applied to the back of the hand was evaluated and is shown in Table 2. In addition, the meaning of each symbol shown in Table 2 is as follows.
A: Feeling of roughness is not felt at all B: Feeling of roughness is hardly felt C: Feeling of roughness is felt but can be spread D: Feeling of roughness is felt

<Color tone>
Using a colorimetric color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., model “ZE 2000”), the L value (lightness), a value (green to red chromaticity), b value (blue to Yellow chromaticity) was measured and the respective values are shown in Table 2. For the measurement, 5 g of magnetic powder for cosmetics was used.

As is known from Table 2, the sample in which the volume average particle size, the content of the large particle and the content of the small particle are controlled within the above specific range is excellent in all the characteristics of adsorption removal, touch and color tone. It became suitable for cosmetics.

Claims

It is a magnetic powder for cosmetics that can be adsorbed and removed by magnetic force from the cosmetics applied to the skin,
The magnetite content is 80% by mass or more, and the balance consists of wustite, hematite and inevitable impurities,
The volume average particle size obtained from the particle size distribution obtained by the laser diffraction scattering method is 50 to 75 μm,
A magnetic powder for cosmetics, wherein the content of particles having a particle size of less than 37 μm is 15% by mass or less, and the content of particles having a particle size of 105 μm or more is 5% by mass or less.
The magnetic powder for cosmetics according to claim 1, wherein the hematite content is 5% by mass or less.
The cosmetic magnetic powder according to claim 1 or 2, wherein the transmittance at a wavelength of 474 nm of a supernatant obtained by dispersing the cosmetic magnetic powder in methanol is 90% or more. Magnetic powder for agent.
The magnetic powder for cosmetics according to any one of claims 1 to 3, wherein the content of wustite is 15% by mass or less.
The magnetic powder for cosmetics according to any one of claims 1 to 4, wherein the saturation magnetization is 80 Am 2 / kg or more.
6. The cosmetic magnetic powder according to claim 1, wherein the apparent density is 1.95 to 2.65 g / cm 3 .
The magnetic powder for cosmetics according to any one of claims 1 to 6, wherein the magnetic powder for cosmetics has a surface area of 200 to 450 cm 2 / g as measured using an air permeation method. .