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EP-3315575-B1 - METHOD FOR PRODUCING ULTRAVIOLET PROTECTIVE AGENT COMPOSITION, AND ULTRAVIOLET PROTECTIVE AGENT COMPOSITION OBTAINED THEREBY

EP3315575B1EP 3315575 B1EP3315575 B1EP 3315575B1EP-3315575-B1

Inventors

  • ENOMURA MASAKAZU
  • HONDA DAISUKE

Dates

Publication Date
20260506
Application Date
20160624

Claims (8)

  1. An ultraviolet protective agent composition which may be obtained by precipitating iron oxide microparticles by mixing with a microreactor an iron oxide raw material fluid containing at least Fe 3+ ion, and an iron oxide precipitation fluid containing at least a basic substance, followed by dispersing the precipitated iron oxide microparticles in a dispersion medium, wherein a primary particle diameter of the iron oxide microparticles is less than 25 nm, more than 90% of the iron oxide microparticles is single crystals; and wherein a haze value of a dispersion of the iron oxide microparticles is 2.0% or less, wherein the dispersion is a dispersion in which the iron oxide microparticles are dispersed in propylene glycol at the iron oxide concentration of 0.005 wt%, and the haze value is measured by using a liquid cell of thickness of 1 mm,and a transmittance of a dispersion of the iron oxide microparticles for the light of the wavelengths of 200 to 420 nm is 2.0% or less, wherein the dispersion is a dispersion in which the iron oxide microparticles are dispersed in propylene glycol at the iron oxide concentration of 0.005 wt%, and the transmittance is measured by using a liquid cell of thickness of 1 cm.
  2. The ultraviolet protective agent composition according to claim 1, wherein a transmittance of the iron oxide microparticle dispersion for the light of the wavelengths of 650 to 800 nm is 80% or more.
  3. The ultraviolet protective agent composition according to claim 1 or claim 2, wherein a secondary particle diameter of the iron oxide microparticles is 50 nm or less.
  4. The ultraviolet protective agent composition according to any one of claims 1 to 3, wherein a molar absorption coefficient of the iron oxide microparticle dispersion for the light of the wavelength of 400 nm is 500 L/(mol·cm) or more, and a molar absorption coefficient of the iron oxide microparticle dispersion for the light of the wavelength of 220 nm is 3000 L/(mol·cm) or more.
  5. The ultraviolet protective agent composition according to any one of claims 1 to 4, wherein the iron oxide microparticles comprise iron oxide microparticles in which the ratio of short axis to long axis is in the range of 0.5 to 1.0.
  6. The ultraviolet protective agent composition according to any one of claims 1 to 5, wherein the iron oxide is α-hematite.
  7. A method of producing an ultraviolet protective agent composition according to any one of claims 1 to 6, which comprises at least step (a) of precipitating iron oxide microparticles by mixing with a microreactor an iron oxide raw material fluid containing at least Fe 3+ ion, and an iron oxide precipitation fluid containing at least a basic substance, and step (b) of dispersing the above precipitated iron oxide microparticles in a dispersion medium to obtain an iron oxide microparticle dispersion, wherein as a microreactor is used a fluid processing machine equipped with the first processing surface and the second processing surface which are disposed so as to face each other, being capable of approaching to and separating from each other, at least one of which rotates relatively to the other; in a step (a), the introduction pressure of both fluids to be processed of the iron oxide raw material fluid and the iron oxide precipitation fluid exceeds the standard pressure, and the iron oxide raw material fluid, at a temperature which is higher than the normal boiling point of the iron oxide raw material fluid and lower than the boiling point under the introduction pressure, and the iron oxide precipitation fluid, are introduced between the first processing surface and the second processing surface; a separation force acting in the direction of separating the first processing surface and the second processing surface is generated by an introduction pressure of the fluids to be processed between the first processing surface and the second processing surface, so that the interval between the first processing surface and the second processing surface is maintained to be 1 mm or less by a pressure balance between the separation force and the force applied in the direction of approximating the first processing surface and the second processing surface; the at least two fluids to be processed are merged between the first processing surface and the second processing surface which are maintained with the interval of 1 mm or less, and are passed between the first processing surface and the second processing surface, to form a thin film fluid; the fluids to be processed are mixed in the thin film fluid to precipitate the iron oxide microparticles, and pH of the fluid mixed in the space between the processing surfaces is 6 to 14.
  8. The method of producing an ultraviolet protective agent composition according to claim 7, comprising step (a-2) of performing an additional stirring treatment to the discharged fluid to be processed, after discharging the fluid to be processed from the space between the processing surfaces and before step (b), wherein pH of the fluid obtained in step (a-2) is 6 to 14.

Description

TECHNICAL FIELD The present invention relates to a method of producing an ultraviolet protective agent composition, and an ultraviolet protective agent composition obtained thereby. BACKGROUND ART An ultraviolet protective agent composition is used in the optical field or a medical material, or in a resin composition used in the electrical and electronic fields, or in a sunscreen in the cosmetics field, or in various paints or the like. When used as cosmetics, transparency and safety are important in addition to the ultraviolet protection ability, for direct application to the skin. When used as a paint, the composition is used normally to protect against effect of ultraviolet rays on a color material such as a paint used in a separate foundation, and a pigment used in the paint and the like. Therefore, the ultraviolet protection ability as well as transmittance of a light other than ultraviolet ray, in particular a visible light are important. That is, for an ultraviolet protective agent composition, an ability to absorb or shield ultraviolet rays as well as transparency are required. As an ultraviolet protective agent composition, Patent Literature 1 discloses an ultraviolet shielding agent comprising an anatase type titanium oxide having an average particle size of 0.6 to 0.8 µm and an iron oxide, and cosmetics containing the same. Patent Literature 2 discloses a transparent thermoplastic resin composition of a haze value of 3% or less with an absorbing ability to a light of the wavelength of 420 nm or less, by containing an ultraviolet absorber such as iron oxide/titanium oxide having an average primary particle diameter of 10 to 80 nm, a benzotriazole compound or a benzoate compounds. Further, Patent Literature 3 discloses a method of producing α-ferric oxide of 0.01 to 0.06 µm, having excellent dispersibility, ultraviolet shielding property and transparency, which surface is coated by a polyhydric alcohol and an organosiloxane, and a thermoplastic resin molded product. However, in the ultraviolet protective agent composition as described in Patent Literature 1, since a large particle size of titanium oxide or iron oxide is used to shield an ultraviolet ray, it is difficult to ensure transparency of the ultraviolet protective agent composition. Moreover, ultraviolet absorbing ability and transparency of the wavelength of 420 nm by the ultraviolet protective agent composition described in Patent Literature 2 are insufficient, and in addition, since protection against a light of the wavelength up to about 420 nm only by iron oxide/titanium oxide is insufficient, it is necessary to use an organic material such as a benzotriazole compound and a benzoate compound which is inferior in durability compared with an inorganic compound, and thus, the ultraviolet protective agent composition described in Patent Literature 2 has poor stability and difficulty in a long time of use. Further, a thermoplastic resin molded product using the α-ferric oxide produced by the method of Patent Literature 3 has insufficient transparency, and in addition, as described in Patent Literature 2, it is necessary for improving the dispersibility to coat the α-ferric oxide surface with an organic compound such as a polyhydric alcohol and an organosiloxane which is inferior in durability compared with an inorganic compound, and thus, the thermoplastic resin molded product of Patent Literature 3 has poor stability and difficulty in a long time of use. Although Patent Literature 3 describes α-ferric oxide which surface is coated with a polyhydric alcohol and an organosiloxane, and a method of producing a thermoplastic resin molded product in which the α-ferric oxide is dispersed, it does not describe a method of producing α-ferric oxide microparticles themselves. Patent Literature 4 filed by the present applicant discloses a method of producing a titanium dioxide supermicroparticles by precipitating microparticles of titanium dioxide between two processing surfaces being capable of approaching to and separating from each other and rotating relative to each other. Patent Literature 5 filed by the present applicant discloses a method of producing various nanoparticles of iron oxides and the like. However, the titanium dioxide supermicroparticles produced by the method described in Patent Literature 4, similarly to conventional titanium dioxide microparticles, have high absorbing ability of so-called UVB of the ultraviolet wavelength of 290 to 320 nm, but poor absorbing ability of so-called UVA of the ultraviolet wavelength longer than 320 nm, particularly up to 420 nm. Moreover, the iron oxide nanoparticles described in Patent Literature 5 are the nanoparticles of black iron oxide (Fe3O4: magnetite) and yellow iron oxide (FeOOH: goethite), and it was not observed that these iron oxide nanoparticles have ultraviolet absorbing ability of a wavelength up to 420 nm. CITATION LIST PATENT LITERATURE Patent Literature 1: JP 2014-169234Patent Lite