glass powder

Abstract

To provide a glass powder suitable for use in a cosmetic.SOLUTION: Provided is glass powder in which D50 is 1 μm or more and 15 μm or less, D50 / 2 is 8% or more, and which substantially consists of spherical-shaped glass particles. Note that D50 denotes a particle diameter at which a cumulative volume from smaller particle diameters in a particle size distribution measured by a laser diffraction / scattering method becomes 50%, D50 / 2 denotes a ratio of a cumulative volume until a particle diameter reaches 1 / 2 of D50 from smaller particle diameters in a particle size distribution, and the spherical shape is a shape in which a ratio R2 / R1 of a diameter R2 orthogonal to the longest diameter R1 to the diameter R1 is 0.8 or more in an observed image of particles observed by using a scanning electron microscope.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to glass powder. More specifically, the present invention relates to glass powder suitable for use, for example, in cosmetics.

Background Art

[0002] Powders may be incorporated into cosmetics to improve slipperiness, impart a light-scattering effect, etc. Powders are frequently used in makeup cosmetics typified by foundation. As organic powders, silicone, cellulose, nylon, etc. are used. As inorganic powders, silica, glass, etc. are used. Patent Document 1 discloses a transparent solid composition containing spherical powder with an average particle size of 3 to 30 μm as a cosmetic.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Inorganic powders such as glass powder do not generate microplastics after disposal, unlike organic powders. However, inorganic powders may give the skin a dry feeling and bulkiness. In addition, inorganic powders may also inhibit the formability of press powder-type cosmetics. Therefore, an object of the present invention is to provide glass powder suitable for use in cosmetics.

Means for Solving the Problems

[0005] The present invention, from its first aspect, provides glass powder having a D50 of 1 μm or more and 15 μm or less, and a D50 / 2 of 8% or more. However, D50 is the particle size at which the cumulative volume from the smaller particle size side in the particle size distribution measured by laser diffraction and scattering method reaches 50%, and D50 / 2 is the ratio of the cumulative volume from the smaller particle size side to half the particle size of D50 in the aforementioned particle size distribution.

[0006] From its second aspect, the present invention, The present invention provides glass powder having a hardness A of 1.5 or higher, as measured when it is formed into a cylindrical press-molded body with a height of 5 mm. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical cavity inside, and the hardness A is the hardness measured using a Type A durometer specified in Japanese Industrial Standard (JIS) K 6253-2012. [Effects of the Invention]

[0007] The present invention provides a glass powder suitable for use in cosmetics. In at least preferred embodiments, the present invention can provide at least one effect selected from i) and ii) below. i) It easily gives the skin a moist feeling. ii) It is less likely to interfere with the moldability of pressed powder type cosmetics. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the results of observing a glass powder according to an example of the present invention using a scanning electron microscope (SEM). [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below, but the following description is not intended to limit the present invention to any particular embodiment. In this specification, "main component" means the component with the highest mass content. "Spherical" means a shape in which the ratio R2 / R1 of the longest diameter R1 to the diameter R2 perpendicular to diameter R1 of the granules is 0.8 or more. "Perfectly spherical" means a shape in which the ratio R2 / R1 of the longest diameter R1 to the diameter R2 perpendicular to diameter R1 of the granules is 0.9 or more. The determination of whether a shape is "spherical" or "perfectly spherical" can be made based on the observed image obtained by observation using an SEM. When glass powder is said to be "substantially composed of predetermined glass granules," it means that 90% or more, and more specifically 95% or more, of the glass granules constituting the glass powder on a number basis correspond to the predetermined glass granules. However, the ratio on a number basis can be determined based on 50 granules of any choice. The upper and lower limits of the numerical values ​​described below are not described individually, but can be any combination of them.

[0010] (particle size distribution) The D50 of the glass powder in this embodiment may be 1 μm or more, 2 μm or more, 3 μm or more, or even 4 μm or more. If D50 is too small, the dispersibility of the glass powder in cosmetics may decrease. D50 may be 15 μm or less, 13 μm or less, 11 μm or less, or even 10.5 μm or less. If D50 is too large, it may not be possible to maintain a good feel on the skin. D50 / 2 may be 8% or more, 10% or more, 12% or more, 14% or more, or even 16% or more, and in some cases may be 18% or more. D50 / 2 is an index that shows the proportion of particles with relatively small particle sizes. There is no particular upper limit to D50 / 2, but it may be 40% or less, 35% or less, or even 30% or less.

[0011] Glass powder with a D50 / 2 particle size that is not too small tends to give the skin a moisturizing feel. This is thought to be because smaller particles are sufficiently interposed between the relatively larger particles when they come into contact with the skin. Glass powder is relatively harder than organic powder, which is inherently disadvantageous when it comes to giving a moisturizing feel. The ability to impart a moisturizing feel by controlling the particle size distribution is useful in mass production, for example, because it eliminates the need for surface modification of inorganic powders.

[0012] Glass powder with a D50 / 2 value that is not too small is less likely to impede the moldability of the cosmetic material, and is therefore superior in this respect as well. The degree of influence on the moldability of the cosmetic material can be evaluated by the moldability of the glass powder itself. The moldability of the glass powder can be evaluated by the hardness of the press-molded product of the glass powder.

[0013] The lower limit of D10 for glass powder is not particularly limited, but it may be 0.3 μm or more, 0.7 μm or more, or even 1 μm or more. Similarly, the upper limit of D10 is not limited, but it may be 8 μm or less, 5 μm or less, or even 3 μm or less. The lower limit of D90 for glass powder is not particularly limited, but it may be 1 μm or more, 5 μm or more, or even 7 μm or more. Similarly, the upper limit of D90 is not limited, but it may be 50 μm or less, 40 μm or less, or even 25 μm or less. Note that D10 and D90 can be determined by replacing "50%" in D50 with "10%" or "90%", respectively.

[0014] The ratio of D90 to D10, D90 / D10, is an indicator of the spread of particle size distribution. D90 / D10 is not particularly limited, but may be 4 or more, 5 or more, or even 6 or more. D90 / D10 is not particularly limited, but may be 50 or less, 30 or less, 15 or less, 12 or less, even 10 or less, and in some cases 9 or less. A suitable range of D90 / D10, especially between 4 and 20, between 5 and 10, and even between 5 and 9, is appropriate for mitigating the degree of influence on the moldability of the cosmetic composition.

[0015] (Hardness of press-molded body) The hardness A of the press-molded glass powder in this embodiment may be 1.5 or higher, 2 or higher, more preferably 2.2 or higher, and in some cases 2.5 or higher, and especially 3 or higher. A high hardness in the press-molded glass powder serves as an indicator of mitigating the influence on the moldability of cosmetics containing glass powder. The upper limit of the hardness A of the press-molded glass powder is not particularly limited, but for example, it is 20 or less, and more preferably 10 or less. However, hardness A is based on the hardness measured using a Type A durometer. Based on the hardness F measured using an Asker rubber hardness tester Type F, the hardness (hardness F) of the press-molded glass powder in this embodiment may be 60 or higher, 70 or higher, 80 or higher, 90 or higher, and even 95 or higher. Details of the method for manufacturing the test press-molded body and the evaluation method for hardness A and F are described in the Examples section. Glass powder with high hardness in the press-molded body is assumed to have a sufficient amount of relatively small particles interposed between relatively large particles.

[0016] (Composition of glass powder) The composition of the glass powder is not particularly limited and may be various compositions mainly composed of oxides, such as silicon dioxide. Glass compositions mainly composed of silicon dioxide may be various compositions called soda-lime glass, borosilicate glass, aluminosilicate glass, etc. The glass composition may be at least one selected from the group consisting of borosilicate (Al / Ca / copper / Na), borosilicate (Ca / Al), borosilicate (Ca / Na), and borosilicate (Ca / titanium), as indicated by the INCI (International Nomenclature of Cosmetic Ingredients) name. The glass composition may be at least one selected from the group consisting of borosilicate (Ca / Al), borosilicate (Ca / Na), and borosilicate (Ca / titanium), as indicated by the INCI name. The glass composition may be at least one selected from the group consisting of borosilicate (Ca / Al) and borosilicate (Ca / Na), as indicated by the INCI name. In the above composition names that include "borosilicate" in the INCI name, the boron oxide content may be 0-13% by mass. In other words, even a glass composition that does not contain boron oxide may be considered a composition that includes "borosilicate" in the INCI name. The composition of the glass powder may have a higher calcium oxide content than ordinary soda-lime glass, specifically a calcium oxide content of 16% or more by mass, and even 18% or more. The composition of the glass powder may have a higher aluminum oxide content than ordinary soda-lime glass, specifically a aluminum oxide content of 5% or more by mass, and even 8% or more. The composition of the glass powder may have a lower sodium oxide content than ordinary soda-lime glass, specifically an aluminum oxide content of 10% or less by mass, and even 7% or less. Furthermore, glass compositions with a softening point higher than that of soda-lime glass, specifically glass compositions with a softening point of 780°C or higher, 800°C or higher, and even 830°C or higher, are suitable for the glass powder of this embodiment. The softening point is when the viscosity of the glass is 10 7.6 This is the temperature at which the temperature becomes dPa·s.

[0017] (Shape, etc. of particles constituting glass powder) The shape of the particles constituting the glass powder is not particularly limited, and may be spherical or may be truly spherical. The glass powder may be substantially composed of spherical glass granules. The glass powder may be substantially composed of truly spherical glass granules. However, the glass powder of the present embodiment can have various shapes. Further, the glass powder may be substantially composed of solid glass granules. Solid glass granules are suitable for providing a sufficient moist feeling compared to hollow glass granules.

[0018] (Manufacturing method of glass powder) In the present embodiment, the glass powder can be obtained, for example, by a manufacturing method including pulverizing a raw material glass powder. The pulverization step is not particularly limited and can be carried out using, for example, various known mills. There is also no particular limitation on the raw material glass powder, and raw material powders having various shapes such as pellet shape, flake shape, and spherical shape can be used.

[0019] The pulverization conditions for adjusting the particle size differ depending on the pulverization method. For example, when describing a ball mill, as is well known, they are the pulverization time, rotation speed, ball filling rate, ball diameter, etc. After pulverization, glass powder having a diameter exceeding a predetermined diameter or less than a predetermined diameter may be removed by using, for example, a sieve or a filter. Adjustment of the particle size distribution itself can be carried out by applying known techniques.

[0020] The manufacturing method of the glass powder may further include spheroidizing the glass powder obtained by pulverization. The spheroidization step can be carried out, for example, by heating the glass powder. The heating temperature can be determined in consideration of the composition, particle size distribution, etc. of the glass powder. If the heating temperature is too high, the glass powder with a small particle size may foam. Also, a moderately low heating temperature is suitable for maintaining the ratio of relatively small granules constituting the glass powder. According to the study of the present inventor, the conventionally applied heating temperature favorable for improving the manufacturing efficiency reduces the ratio of relatively small granules that can be indicated by D50 / 2.

[0021] (Cosmetics) The cosmetic composition into which the glass powder of this embodiment is incorporated is not particularly limited, but for example, makeup cosmetics such as foundation and face powder are suitable. There are also no particular restrictions on the shape of the cosmetic composition, but the glass powder of this embodiment is suitable for incorporation into solid cosmetic compositions.

[0022] The glass powder content in the cosmetic composition of this embodiment may be, for example, 0.1% or more, 5% or more, or even 10% or more by mass. There is no particular upper limit to this content, but it may be 90% or less, or even 50% or less.

[0023] As described above, this embodiment provides the following technology.

[0024] The first technology is, D50 is between 1 μm and 15 μm. This is glass powder with a D50 / 2 content of 8% or more. However, D50 is the particle size at which the cumulative volume from the smaller particle size side in the particle size distribution measured by laser diffraction and scattering method reaches 50%, and D50 / 2 is the ratio of the cumulative volume from the smaller particle size side to half the particle size of D50 in the aforementioned particle size distribution.

[0025] The second technology is, The glass powder described in the first technology is formed into a cylindrical press-molded body with a height of 5 mm and has a hardness A of 1.5 or higher. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical cavity inside, and the hardness A is the hardness measured using a Type A durometer specified in Japanese Industrial Standard (JIS) K 6253-2012.

[0026] The third technology is, This is a glass powder whose hardness A, measured when formed into a cylindrical press-molded body with a height of 5 mm, is 1.5 or higher. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical cavity inside, and the hardness A is the hardness measured using a Type A durometer specified in Japanese Industrial Standard (JIS) K 6253-2012.

[0027] The fourth technology is, The glass powder described in any one of the first to third technologies is substantially composed of spherical glass particles. However, a spherical shape is defined as a shape in which, in an observation image of a particle body using a scanning electron microscope, the ratio R2 / R1 of the diameter perpendicular to the longest diameter R1 to the longest diameter R1 is 0.8 or greater.

[0028] The fifth technology is, The glass powder described in any one of the first to fourth technologies, wherein the ratio of D90 to D10, D90 / D10, is 4.0 or greater. However, D10 is the particle size at which the cumulative volume from the smallest particle size to the smallest particle size in the particle size distribution measured by laser diffraction and scattering method accounts for 10%, and D90 is the particle size at which the cumulative volume from the smallest particle size to the smallest particle size in the aforementioned particle size distribution accounts for 90%.

[0029] The sixth technology is, The glass powder described in any one of the first to fifth technologies has a glass composition with a softening point of 780°C or higher.

[0030] The seventh technology is, The glass powder described in the first technology is formed into a cylindrical press-molded body with a height of 5 mm and has a hardness F of 60 or higher. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical cavity inside, and the hardness F is the hardness measured using an Asker rubber hardness tester type F.

[0031] The eighth technology is, A cosmetic composition containing glass powder as described in any one of the first to seventh technologies.

[0032] Furthermore, this embodiment also provides the following ninth technology. The ninth technology is, This is a glass powder with a hardness F of 60 or higher, measured by forming it into a cylindrical press-molded body with a height of 5 mm. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical cavity inside, and the hardness F is the hardness measured using an Asker rubber hardness tester type F. [Examples]

[0033] The present invention will be described in more detail below with reference to examples. First, a specific evaluation method will be explained.

[0034] (particle size distribution) The particle size distribution of glass powder was measured using laser diffraction and scattering. A particle size distribution analyzer (Microtrac MT3300EXII) was used for the measurements. The particle sizes at which the cumulative volume from the smallest particle size accounted for 10%, 50%, and 90% were measured and defined as D10, D50, and D90, respectively. In addition, the ratio of the cumulative volume of particles from the smallest particle size down to half the particle size of D50 was obtained as D50 / 2. Furthermore, D90 / D10 was calculated.

[0035] (Sensory evaluation) A small amount of glass powder was taken on a finger and applied to the back of the hand, and the texture and dryness of the powder were evaluated. Texture was evaluated as either moist or dry. Dryness was evaluated on a three-point scale: G: not dry, F: slightly dry, NG: dry.

[0036] (Shape retention and hardness of press-formed products) • Forming of press-molded products A cylindrical press-molded body was obtained by compression molding glass powder using a mold. The press-molded body was cylindrical with a base diameter of 58 mm and a height of 5 mm. Compression molding was performed by applying a pressure of 4 MPa along the height direction of the cylinder. ·Shape retention A pressure of 10 kPa was applied to a circular area within a 10 mm radius from the center of the bottom surface of the press-formed body, and the change in the shape of the press-formed body was observed. The results were evaluated in two stages: G: resistant to collapse, NG: easily collapsed. ·hardness The hardness A and F of the bottom surface of the press-molded body was measured using a Type A durometer specified in JIS K 6253-2012 and an Asker rubber hardness tester Type F manufactured by Polymer Instruments Co., Ltd. The measurement time was 1 second, i.e., the reading within 1 second after contacting the durometer or other instrument with the press-molded body was taken as the hardness.

[0037] (Example 1) Glass particles having a glass composition corresponding to borosilicate (Ca / Al) were crushed in a ball mill to obtain glass powder. The glass composition of borosilicate (Ca / Al) used is shown in Table 1. However, since this glass composition also corresponds to borosilicate (Ca / Na) and borosilicate (Ca / Titanium), it can be expressed as any of the three types including borosilicate (Ca / Al). The softening point of this glass composition was 876°C. The crushing conditions in the ball mill were adjusted so that the D50 of the glass powder was 6 μm. The crushed glass powder had a shape that did not correspond to a spherical shape. Next, the obtained glass powder was spheroidized using a flame-type spheroidizing device (Taiyo Nippon Sanso Corporation "CERAMELT"). The burner combustion temperature of the spheroidizing device was adjusted in the range of 2000 to 2400°C. The glass powder was supplied at a rate of 10 kg / h using a raw material feeder. The supplied glass powder was heated and spheroidized. The spherical glass particles were recovered using a cyclone. Meanwhile, fine powder smaller than a few hundred nanometers was recovered using a bag filter and separated from the glass particles.

[0038] [Table 1]

[0039] (Example 2) Glass granules were obtained in the same manner as in Example 1, except that the grinding conditions were changed, specifically by increasing the size of the balls introduced into the ball mill.

[0040] (Comparative Example 1) Except for changing the spheroidizing conditions, the burner combustion temperature of the spheroidizing apparatus used to obtain the glass granules was adjusted to a range of 2400 to 2700°C, in the same manner as in Example 2.

[0041] (Comparative Example 2) Glass granules were obtained in the same manner as in Example 1, except that commercially available soda-lime glass particles were used and the grinding conditions were changed, specifically by making the ball size even larger than in Example 2. The softening point of the soda-lime glass used was approximately 730°C.

[0042] (Comparative Examples 3 and 4) In Comparative Example 3, spherical silica (AGC SI-TEC Co., Ltd. "L-51") was used instead of glass granules, and in Comparative Example 4, spherical silicone (Shin-Etsu Chemical Co., Ltd. "KSP-100") was used instead, and measurements were performed.

[0043] The measurement results are summarized in Table 2.

[0044] [Table 2]

[0045] In Comparative Examples 3 and 4, hardness measurements could not be obtained because the press-molded bodies cracked during the hardness measurement process. Furthermore, observation using SEM revealed that the glass powder obtained from Examples 1 and 2 was substantially composed of perfectly spherical and solid granules. The glass powder obtained from Comparative Examples 1 and 2 was also perfectly spherical. Similarly, an SEM image of the glass powder from Example 1 is shown in Figure 1.

[0046] Next, foundations were prepared and evaluated using the powders obtained from Example 1 and Comparative Examples 1 and 3. The evaluation method was as described above. The foundation formulations and evaluation results are shown in Table 3.

[0047] [Table 3]

Claims

1. D50 is between 1 μm and 15 μm. D50 / 2 is 8% or more. The ratio of D90 to D10, D90 / D10, is between 5 and 12. It is substantially composed of spherical glass particles, It has a composition in which silicon dioxide is the main component and the calcium oxide content is 16% or more by mass. Glass powder for cosmetic use. However, D10, D50, and D90 are particle sizes in which the cumulative volume from the smallest particle size to the smallest particle size accounts for 10%, 50%, and 90%, respectively, in the particle size distribution measured by laser diffraction and scattering, D50 / 2 is the ratio of the cumulative volume from the smallest particle size to half the particle size of D50 in the particle size distribution, and spherical is a shape in which the ratio R2 / R1 of the diameter perpendicular to the longest diameter R1 to the longest diameter R1 in the observation image of the particle body observed using a scanning electron microscope is 0.8 or more.

2. The glass powder according to claim 1, wherein the hardness A measured when formed into a cylindrical press-molded body with a height of 5 mm is 1.5 or higher. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical cavity inside, and the hardness A is the hardness measured using a Type A durometer specified in Japanese Industrial Standard (JIS) K 6253-2012.

3. The hardness A measured after forming a cylindrical press-molded body with a height of 5 mm is 1.5 or higher. It has a composition mainly composed of silicon dioxide, with a calcium oxide content of 16% or more by mass, and a softening point of 780°C or higher. A cosmetic glass powder substantially composed of spherical glass granules. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical void inside, the hardness A is the hardness measured using a Type A durometer specified in Japanese Industrial Standard (JIS) K 6253-2012, and spherical is a shape in which the ratio R2 / R1 of the diameter perpendicular to the longest diameter R1 to the observation image of the granules observed using a scanning electron microscope is 0.8 or more.

4. The glass powder according to claim 3, wherein the ratio of D90 to D10, D90 / D10, is 4.0 or greater. However, D10 is the particle size at which the cumulative volume from the smallest particle size in the particle size distribution measured by laser diffraction and scattering method accounts for 10%, and D90 is the particle size at which the cumulative volume from the smallest particle size in the aforementioned particle size distribution accounts for 90%.

5. The glass powder according to claim 1, having a glass composition with a softening point of 780°C or higher.

6. The glass powder according to claim 1 or 3, wherein the hardness F measured when formed into a cylindrical press-molded body with a height of 5 mm is 60 or higher. However, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical cavity inside, and the hardness F is the hardness measured using an Asker rubber hardness tester type F.

7. D50 is between 1 μm and 15 μm. D50 / 2 is 8% or more. It is substantially composed of spherical glass particles. Glass powder, or The hardness A measured after forming a cylindrical press-molded body with a height of 5 mm is 1.5 or higher. It is substantially composed of spherical glass particles. Glass powder, including Cosmetics. However, D50 is the particle size at which the cumulative volume from the smaller particle size side in the particle size distribution measured by laser diffraction and scattering method reaches 50%, D50 / 2 is the ratio of the cumulative volume from the smaller particle size side to half the particle size of D50 in the particle size distribution, spherical is a shape in which the ratio R2 / R1 of the diameter perpendicular to the longest diameter R1 to the observation image of the granules observed using a scanning electron microscope is 0.8 or more, the press-molded body is obtained by applying a pressure of 4 MPa along the height direction of the cylinder to the glass powder filled inside a mold having a cylindrical void inside, and the hardness A is the hardness measured using a Type A durometer specified in Japanese Industrial Standard (JIS) K 6253-2012.

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