JP2016150961A - Method for producing photochromic fine particles and photochromic fine particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a method for producing photochromic fine particles simply in a short time using a highly stable emulsion without using a special apparatus; and photochromic fine particles obtained by the method.SOLUTION: There is provided a method for producing photochromic fine particles which comprises: a step of mixing an organic phase containing a polymerizable monomer (A) and a photochromic compound (B), an active agent phase containing a nonionic surfactant (C) and an auxiliary surfactant (D) and a water phase containing a water component (E) to obtain a single phase microemulsion composition; a step of obtaining an organic phase (O phase)/water phase (W phase) nanoemulsion from the single phase microemulsion; and a step of polymerizing the organic phase (O phase)/water phase (W phase) nanoemulsion.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing photochromic fine particles capable of producing organic fine particles (hereinafter also referred to as photochromic fine particles) having a size of nano to micron order containing a photochromic compound.

  Photochromism is a reversible action that quickly changes color when a compound is irradiated with light containing ultraviolet light, such as sunlight or light from a mercury lamp, and returns to its original color when light is turned off and placed in a dark place. It is applied to various uses. As photochromic compounds having such properties, fulgimide compounds, spirooxazine compounds, chromene compounds and the like have been found. Since these photochromic compounds can be made into optical articles having photochromic properties by being compounded with plastics, many studies have been made on compounding.

  For example, photochromism is also applied in the field of spectacle lenses. Photochromic eyeglass lenses that use photochromic compounds function as sunglasses by rapidly coloring the lens outdoors when exposed to light containing ultraviolet rays such as sunlight, and fading indoors where there is no such light irradiation. It functions as normal transparent glasses, and its demand has increased in recent years.

  In addition to ophthalmic materials such as spectacle lenses, intraocular lenses, and contact lenses, photochromic compounds include dimming materials such as window glass and car window glass, recording media such as optical memory and electronic paper, ultraviolet checkers, etc. It has been put to practical use or development in a wide range of applications such as sensor materials, clothing materials such as print shirts, cosmetic materials, printing inks, decorative materials, and toys.

  As a method of obtaining an optical article having photochromic properties using the above photochromic compound, a method of directly obtaining a photochromic lens by dissolving a photochromic compound in a monomer and polymerizing it (see Patent Document 1), or having photochromic properties A method of providing a coating layer having photochromic properties on the surface of a non-plastic (see Patent Document 2) is known.

  About these photochromic compounds and plastic optical articles having photochromic properties containing them, from the viewpoint of photochromic action, (a) the degree of coloring in the visible light region before irradiation with ultraviolet rays (hereinafter referred to as initial coloring) is low. (B) The degree of coloration (hereinafter referred to as the color density) when irradiated with ultraviolet rays is high, and (c) the speed (hereinafter referred to as the fading rate) from when the irradiation of ultraviolet rays is stopped until the original state is restored. Fast, (2) good repetitive durability of this reversible action, (e) high storage stability, (f) easy to mold as an optical article, and (g) strong mechanical strength as an optical article. ing. Among these characteristics, there is a problem that photochromic characteristics such as color density and fading speed are easily influenced by a substrate (also referred to as a matrix) containing a photochromic compound. This is because the expression of photochromic properties in photochromic compounds such as fulgimide compounds, spirooxazine compounds, and chromene compounds is expressed by changes in molecular structure such as ring-opening reaction by photoexcitation with ultraviolet light. Therefore, in order to develop high photochromic properties, a free space that can change the structure of the photochromic compound is required in the matrix. On the other hand, in order to ensure mechanical strength as an optical article, it is necessary to make it a stiffer optical article, and there is a tendency to form a matrix with a high degree of crosslinking and a small free space. Tend to be low. As described above, in general, the characteristics of photochromic properties such as color density and fading speed and mechanical strength are in a trade-off relationship with each other. Furthermore, a photopolymerization initiator may be used during the polymerization of the matrix, and there is a problem that a part of the photochromic compound is deteriorated during the photopolymerization.

  For this reason, fine particles having a size of nano to micron order containing a photochromic compound, that is, photochromic fine particles have been proposed as a material exhibiting excellent photochromic characteristics without depending on a substrate (see Non-Patent Document 1).

  Organic fine particles of nano to micron size can embed various compounds such as drugs inside, so that the degradation effect of inclusions due to the external environment, the release of inclusions to the outside Because it can be expected to be controlled, it is used in pharmaceuticals, agricultural chemicals, cosmetics, paints, foods and other functional materials. For example, in pharmaceutical applications, it is also used as a drug delivery system as a drug delivery system for controlling the release of a drug embedded therein or as an external preparation containing a physiologically active substance. Furthermore, among organic fine particles, organic fine particles having a wavelength smaller than the visible light wavelength (400 to 800 nm) have very small light scattering. Therefore, when such fine particles are uniformly dispersed in a liquid, a substrate, etc., a transparent body is formed. There is a feature that it is obtained.

  Therefore, by making the photochromic fine particles embedded with the photochromic compound, the photochromic characteristics can be expected to be expressed in the fine particles, and the photochromic compound is protected from the matrix environment. Even in the case of being dispersed, it is expected that high photochromic characteristics can be obtained without being affected by the environment of the matrix.

  In general, as a method for obtaining organic fine particles, a chemical method using a chemical reaction such as polymerization, a method obtained using physicochemical phenomena such as drying, precipitation, and aggregation, and mechanical energy are used. The method is used.

  As a chemical method, there is known a method in which a urethane resin is microparticulated in the presence of a compound to be embedded by a polymerization method such as suspension polymerization, miniemulsion polymerization, emulsion (emulsion) polymerization, or dispersion polymerization.

  Here, the suspension polymerization means that a monomer in which a substance (hereinafter also referred to as a core substance) contained in fine particles is dispersed is dispersed into droplets in a continuous phase incompatible with this monomer, and then suspended. It is the polymerization method which performs a polymerization process. Mini-emulsion polymerization is the addition of a monomer and core substance to a continuous aqueous phase, and in order to generate and stably disperse droplets of the order of 100 nm under high shear force, a high concentration surfactant is dissolved in the continuous phase. After that, the polymerization is started by adding a polymerization initiator. In emulsion polymerization, a surfactant, a polymerization initiator, a monomer, and a core substance are added to a continuous aqueous phase, and the surfactant is dissolved at a concentration to form micelles to form solubilized micelles, and then polymerization is performed. How to get started. The precipitation polymerization method is a polymerization method in which a surfactant is not added. A monomer is injected into a continuous phase in which a polymerization initiator is dissolved, dispersed in a droplet state, and radicals are dissolved in the monomer dissolved from the droplet into the continuous phase. Polymerization starts and polymerization grows, and when the chain grows and grows to a critical chain length, it precipitates to form nuclei, and these nuclei agglomerate and coalesce into fine particles.

  Further, as a method utilizing a physicochemical phenomenon, it is a method of performing polymerization after forming an emulsion having a lipophilic phase having a compound to be embedded inside and having a hydrophilic phase outside. In-liquid drying methods, phase inversion emulsification (phase inversion emulsion) methods, coacervation methods, and the like are known (see Non-Patent Document 2).

  Here, the in-liquid drying method means that the organic phase (or aqueous phase) in which the core material is stably dispersed and the shell material is dissolved is made into fine droplets in a continuous phase incompatible with this, and then the shell material is dissolved. This is a method in which the melted shell material is deposited at the same time as the dissolved shell material is deposited by evaporating and removing the solvent being heated under reduced pressure. The phase inversion emulsification method is a method of forming fine particles with phase transition by adding a continuous phase incompatible with the dispersed phase into the dispersed phase in which the core substance is dissolved. After phase inversion occurs, fine particles crosslinked by chemical bonds can be obtained by suspension polymerization or drying in liquid. Furthermore, the coacervation method is a method of making fine particles by dispersing a core substance in a continuous phase dissolved in a shell material, and then applying an appropriate stimulus to precipitate the shell material.

  Various methods for obtaining the above-mentioned photochromic fine particles have been studied. As a study using a chemical method, for example, a hydrophilic monomer, a hydrophobic monomer, and an organic photochromic material are used to form a microemulsion and then polymerized to form a photochromic fine particle. It has been reported that a composition comprising can be obtained. (See Patent Document 3). Furthermore, it has been reported that photochromic fine particles can be obtained as fine particles having a particle diameter of 100 nm or less by miniemulsion polymerization using an acrylic monomer and a crosslinkable spiropyran compound (see Non-Patent Document 3).

International Publication No. 01/005854 International Publication No. 11/125756 Special table 2008-506031

T. Feczko, T. Voncina, “Current Organic Chemistry” (United Arab Emirates), Benthan Science Publishers, 2013, Vol. 17 p. 1771 to 1789 Tanaka Hayato, “Key Points for Nano / Microcapsule Preparation”, First Edition, Techno System Co., Ltd., May 6, 2008, p. 11-27 J. Su, J. Chen and five others, “Polymer Bulletin” (Germany), Springer Berlin Heidelberg, 2008, 61, p. 425-434

  As described above, since the characteristics of the obtained photochromic fine particles can be easily controlled, the chemical method is useful as a method for obtaining the photochromic fine particles, but this method has the following problems. That is, in the method of suspension polymerization or miniemulsion polymerization, it is necessary to disperse minute droplets when forming an emulsion. In order to generate and disperse fine droplets of a polymerizable monomer containing a photochromic compound, it is necessary to add a polymerizable monomer to the aqueous phase and apply a high shearing force. For this reason, an ultrasonic irradiator, a high-pressure homogenizer It is necessary to use equipment such as a high-speed homogenizer. However, production on an industrial scale using an ultrasonic irradiator is difficult. On the other hand, high-pressure homogenizers and high-speed homogenizers are expensive equipments, and there is a problem in producing photochromic fine particles efficiently industrially. In addition, the microemulsion obtained by this method is thermodynamically unstable and has a problem in stability during polymerization. Furthermore, there is a problem that it is difficult to control the particle size and it is difficult to obtain fine particles.

  Accordingly, an object of the present invention is to provide a method for easily producing fine photochromic fine particles in a short time using a highly stable emulsion without using a special apparatus.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result of investigating a method for obtaining a thermodynamically stable emulsion, in a phase inversion emulsification method which is a physical method, an aqueous phase (W phase) is added to an active agent phase including an organic phase (O phase) and a surfactant. To prepare an organic phase (O phase) / aqueous phase (W phase) nanoemulsion by preparing a one-phase microemulsion and further adding an aqueous phase or applying a stimulus such as temperature Confirmed that a thermodynamically stable nanoemulsion was obtained. Here, a one-phase microemulsion is a thermodynamically stable system consisting of one phase, which is a transparent or translucent phase. Furthermore, since the nanoemulsion obtained by the above method has small micelles, it scatters visible light. It was found that the nanoemulsion was small and transparent or translucent, the nanoemulsion was stable even during polymerization, and photochromic fine particles could be obtained efficiently, and the present invention was completed.

  That is, the present invention relates to an organic phase containing a polymerizable monomer (A) and a photochromic compound (B), an active agent phase containing a nonionic surfactant (C) and a co-active agent (D), and a water component ( A step of mixing a water phase containing E) to obtain a one-phase microemulsion composition, a step of obtaining an organic phase (O phase) / water phase (W phase) nanoemulsion from the one-phase microemulsion, and further an organic phase (O phase) / water phase (W phase) This is a method of photochromic fine particles comprising a step of polymerizing a nanoemulsion. The organic phase (O phase) / water phase (W phase) nanoemulsion is a nanoemulsion in which an organic phase is dispersed in an aqueous phase.

  Furthermore, in the method for producing photochromic fine particles of the present invention, the polymerizable monomer (A) is preferably a radical polymerizable monomer.

  Moreover, 2nd this invention is the photochromic microparticles | fine-particles which were manufactured with said manufacturing method and whose average particle diameter is 20-400 nm and contained the photochromic compound inside the polymer of a polymerizable monomer.

  In the method for producing photochromic fine particles of the present invention, a microemulsion is formed through a one-phase microemulsion. Here, the one-phase microemulsion is a microemulsion formed from one phase, and the phase constituting the one-phase microemulsion is a micellar aqueous phase in which oil is completely solubilized or water is completely solubilized. There are those which are a dispersed phase which is a micelle organic solution phase (hereinafter also referred to as a droplet type), and those which are both a continuous phase of an aqueous phase and an organic phase (hereinafter also referred to as a bicontinuous type). Single-phase microemulsions are thermodynamically stable because the micelle diameter is as small as about 100 nm and the interfacial tension between the organic phase and the aqueous phase is almost zero. Furthermore, the one-phase microemulsion has a small micelle diameter of about 100 nm, and thus it is a transparent or translucent emulsion with little visible light scattering.

  Accordingly, it is possible to obtain fine particles having a stable structure by carrying out a polymerization reaction after producing photochromic fine particles from this one-phase microemulsion. Further, since the microemulsion is formed by a physical method, it does not require generation and dispersion of droplets by a high shear force required by a chemical method. Therefore, it is possible to easily produce excellent photochromic fine particles that can be used for many applications including a light control material such as a spectacle lens without using a special device such as a high-pressure homogenizer device.

  The photochromic fine particles obtained by the production method of the present invention contain a photochromic compound inside particles composed of a polymer of a polymerizable monomer, and the particle size is as small as 20 to 400 nm. For this reason, it is easy to disperse | distribute to a solution, a base material, etc. Moreover, since it is below the wavelength of visible light, when used for optical uses, such as a plastic lens base material, it has the characteristics that high transparency is acquired.

The method for producing photochromic fine particles of the present invention comprises a polymerizable monomer (A), an organic phase containing a photochromic compound (B), a nonionic surfactant (C) and an activator phase containing a co-active agent (D), And a step of mixing a water phase containing the water component (E) to obtain a one-phase microemulsion composition, obtaining an organic phase (O phase) / water phase (W phase) nanoemulsion from the one-phase microemulsion, Is characterized by polymerizing an organic phase (O phase) / water phase (W phase) nanoemulsion.
As described above, the one-phase microemulsion composition formed by the method for producing photochromic fine particles of the present invention is a thermodynamically stable emulsion composition, and fine photochromic fine particles can be easily obtained by using such an emulsion. Can be manufactured.

Hereinafter, each component in the manufacturing method of this invention is demonstrated.
Hereinafter, the organic phase is abbreviated as O and the aqueous phase is abbreviated as W. For example, O / W indicates an organic phase (O phase) / water phase (W phase).

<Polymerizable monomer (A)>
As the polymerizable monomer (A) in the method for producing photochromic fine particles of the present invention, known monomers can be used without particular limitation as long as they can form fine particles by a polymerization reaction. Since the polymerization reaction is carried out in the presence of water, radically polymerizable monomers and polyaddition monomers can be used.

  As the radically polymerizable monomer, known ones can be used without any particular limitation, and (meth) acrylic polymerizable monomers having a (meth) acrylic group, vinylic polymerizable monomers having a vinyl group, and allyl groups. The allylic polymerizable monomer can be increased. The radical polymerizable monomer may also have a reactive group (for example, an epoxy group, an oxetanyl group, or an isocyanate group) based on a polymerization mechanism other than the radical polymerizable group.

As the (meth) acrylic polymerizable monomer, a monomer having one or a plurality of (meth) acrylic groups can be used. Examples of (meth) acrylic polymerizable monomers
Ethylene glycol di (meth) acrylate compounds such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate and polyethylene glycol di (meth) acrylate ;
Propylene glycol di (meth) acrylate compounds such as propylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate and polypropylene glycol di (meth) acrylate;
(Meth) acrylate compounds having groups derived from polyols such as trimethylolpropane tri (meth) methacrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, bistrimethylolpropane tetra (meth) acrylate ;
2,2-bis [4- (meth) acryloyloxy ethoxy) phenyl] propane, 2,2-bis [4- (meth) acryloyloxy diethoxy) phenyl] propane, 2,2-bis [4- (meth) ) Acryloyloxy / polyethoxy) phenyl] propane, 2,2-bis (3,5-dibromo-4- (meth) acryloyloxyethoxyphenyl) propane, 2,2-bis (4- (meth) acryloyloxydipropoxyphenyl) ) Bisphenol A di (meth) acrylate compounds such as propane;
Polycarbonate di (meth) acrylate compound obtained by reaction of polycarbonate diol with (meth) acrylic acid;
Monofunctional or polyfunctional urethane (meth) acrylate compounds;
Radical polymerization / epoxy polymerizable monomers such as glycidyl (meth) acrylate, glycidyloxymethyl (meth) acrylate, 2-glycidyloxyethyl (meth) acrylate;
Radical polymerization / OH type polymerizable monomer such as 2-hydroxy (meth) acrylate, 2-hydroxy (meth) acrylate, 2-hydroxypropyl (meth) acrylate;
Radical polymerization / isocyanate type polymerizable monomers such as 2-isocyanatoethyl (meth) acrylate and 2-isocyanatoethyl (meth) acrylate;
Etc. can be mentioned.

  Among these (meth) acrylic polymerizable monomers, it is easy to form fine particles having a visible light wavelength of 400 nm or less, so that ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) ), Ethylene glycol di (meth) acrylate compounds such as tetraethylene glycol di (meth) acrylate and polyethylene glycol di (meth) acrylate are preferred, and ethylene glycol di (meth) acrylate is particularly preferred.

  Examples of vinyl polymerizable monomers having a vinyl group include methyl vinyl ketone, ethyl vinyl ketone, ethyl vinyl ether, styrene, vinyl cyclohexane, butadiene, 1,4-pentadiene, divinyl sulfide, divinyl sulfone, 1,2-divinylbenzene, , 3-Divinyl-1,1,3,3-tetramethylpropanedisiloxane, diethylene glycol divinyl ether, divinyl adipate, divinyl sebacate, ethylene glycol divinyl ether, divinyl sulfoxide, divinyl persulfide, dimethyl divinyl silane, 1,2 , 4-trivinylcyclohexane, methyltrivinylsilane, α-methylstyrene, α-methylstyrene dimer, and the like.

  Examples of allyl polymerizable monomers having an allyl group include diethylene glycol bisallyl carbonate, methoxypolyethylene glycol allyl ether, methoxypolyethylene glycol-polypropylene glycol allyl ether, (meth) acryloyloxypolyethylene glycol-polypropylene glycol allyl ether, vinyloxypolyethylene glycol allyl. Ether can be mentioned.

  Examples of the polyaddition monomer include urethane or urea-based polymerizable monomers (hereinafter also referred to as urethane-based polymerizable monomers) that can form urethane bonds and urea bonds, and epoxy-based polymerizable monomers. Among these, a urethane-based polymerizable monomer is a polymer in which a repeating unit of polymerization is linked by a urethane bond or a urea bond, and an epoxy group, an episulfide group, a thietanyl group, an OH group, an SH group, NH2 as a polymerizable functional group. Monomers into which a group, an NCO group or an NCS group is introduced can be used alone or in combination.

  The urethane bond is formed by a reaction between a polyol and a polyisocyanate, and some of the urethane bonds are formed by a reaction between a polyol and a polyisothiocyanate, or a reaction between a polythiol and a polyisothiocyanate. A thiourethane bond is also included.

  The urea bond is formed by the reaction of polyamine and polyisocyanate, and this urea bond includes the thiourea bond formed by the reaction of polyamine and polyisothiocyanate.

  As understood from the above description, in the present invention, as the urethane-based polymerizable monomer, among the polyol, polythiol, polyamine, polyisocyanate, and polyisothiocyanate, the above urethane bond (thiourethane bond) or urea is used. A plurality of types of compounds are selected and used so that a bond (thiourea bond) is formed.

As the polyol as the polyaddition monomer of the present invention,
Aliphatic alcohols such as ethylene glycol, diethylene glycol, propylene glycol;
Aromatic alcohols such as dihydroxynaphthalene and trihydroxynaphthalene;
Polyester polyols;
Polyether polyols;
Polycaprolactone polyol;
Polycarbonate polyols;
Polyacrylic polyols;
Etc. can be used.

As polythiol,
Aliphatic polythiols such as 1,6-hexanedithiol and 1,2,3-propanetrithiol;
Aromatic polythiols such as 1,3-dimercaptobenzene and 1,2-bis (mercaptomethyl) benzene;
Etc. can be used.

  As the polyamine, hexamethylene diamine, isophorone diamine or the like can be used.

As polyisocyanate,
Aliphatic isocyanates such as ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate;
Cycloaliphatic isocyanates such as isophorone diisocyanate, norbornane diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate;
Aromatic isocyanates;
Diisocyanates containing sulfur atoms;
Etc. can be used.

As polyisothiocyanate,
Aliphatic isothiocyanates such as 1,2-diisothiocyanate ethane, 1,3-diisothiocyanate propane;
Alicyclic isocyanates;
Etc. can be used.

As the epoxy polymerizable monomer as the polyaddition monomer of the present invention,
Aliphatic epoxy compounds such as 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, glycerol triglycidyl ether;
Alicyclic epoxy compounds such as isophoronediol diglycidyl ether and bis-2,2-hydroxycyclohexylpropane diglycidyl ether;
Aromatic epoxy compounds such as resorcin diglycidyl ether and bisphenol A diglycidyl ether;
Etc. can be used.

  Among the polymerizable monomers (A), it is more preferable to use a radical polymerizable monomer because the handling of the monomer is easier. Among the radical polymerizable monomers, a (meth) acrylic polymerizable monomer is more preferable because the polymerization reaction can be easily controlled.

  The polymerizable monomer (A) may be used alone or in combination of two or more. The concentration of the polymerizable monomer (A) used in the present invention is not particularly limited. However, since the stability of the one-phase microemulsion tends to decrease as the concentration of the polymerizable monomer increases, the O / W When producing a one-phase microemulsion, the amount is preferably 1 to 50% by mass based on the total amount.

Next, the photochromic compound (B) will be described. <Photochromic compound (B)>
As the photochromic compound (B) in the method for producing photochromic fine particles of the present invention, known compounds can be used, and these can be used alone or in combination of two or more. .

  Typical examples of such a photochromic compound (B) are fulgide compounds, chromene compounds and spirooxazine compounds. For example, JP-A-2-28154, JP-A-62-2288830, WO94 / 22850. It is disclosed in many documents such as pamphlets and WO96 / 14596 pamphlets.

  In the present invention, among known photochromic compounds, a chromene compound having a naphtho [1,2-b] pyran skeleton is used from the viewpoint of photochromic properties such as color density, initial colorability, durability, and fading speed. Further, it is preferable to use a chromene compound having an indeno [2,1-f] naphtho [1,2-b] pyran skeleton because it is particularly excellent in color density and fading speed.

  Specific examples of the chromene compound particularly preferably used in the present invention include the following chromene compounds.

9-bicyclononylidene-3H-naphtho [1,2-b] pyran A chromene compound having an indeno [2,1-f] naphtho [1,2-b] pyran skeleton represented by the following formula.

In the photochromic fine particles of the present invention having the photochromic compound (B) as an essential component, the photochromic compound (B) is usually used in an amount of 0.001 to 20 parts by mass per 100 parts by mass of the polymerizable monomer. If the amount of photochromic compound used is too small, it will be difficult to develop good photochromic properties. If the amount used is too large, it will be difficult to handle this photochromic composition due to thickening, etc. There is a risk that it will be difficult to express the sex.
Next, the nonionic surfactant (C) will be described.

<Nonionic surfactant (C)>
The nonionic surfactant (C) in the method for producing photochromic fine particles of the present invention is an essential component for forming an emulsion. The nonionic surfactant (C) used in the present invention is not particularly limited, but is a value representing the degree of affinity of the surfactant with water and oil (an organic compound insoluble in water). A certain HLB value is preferably 6 to 20, more preferably 9 to 18. As an example of the nonionic surfactant (C) used in the present invention,
Polyoxyethylene sorbitol fatty acid esters such as tetraisostearic acid polyoxyethylene sorbit;
Polyoxyethylene fatty acid glyceryls such as polyoxyethylene isocetyl glyceryl; polyoxyethylene / methyl polysiloxane copolymers;
Fatty acid polyoxyethylene sorbitan such as polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monooleate;
Tetrafatty acid polyoxyethylene sorbits such as polyisoethylene stearates;
Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene isostearyl ether, polyoxyethylene (7) oleyl ether; maltitol hydroxy aliphatic alkyl ether;
Alkylated polysaccharides;
Alkyl glucosides;
Sucrose fatty acid ester;
Etc.

  Moreover, you may mix 2 or more types of nonionic surfactant (C), and may prepare HLB in the range of 6-15. Here, the total HLB when two or more kinds of surfactants are mixed is obtained by averaging the HLB of each surfactant alone with the mass% as a weight.

  Among these nonionic surfactants (B), tetrafatty acid polyoxyethylene sorbits such as tetraisostearic acid polyoxyethylene sorbite are particularly preferred because they can easily form a one-phase micro-erosion.

<Co-active agent (D)>
The co-active agent (D) in the method for producing photochromic fine particles of the present invention is adsorbed between the hydrophilic groups of adjacent nonionic surfactants (C) in the formation of one-phase micro-erosion, and the organic phase-aqueous phase interface. It works to increase the stability of

As the auxiliary activator (D), polyalkylene derivatives having plural kinds of polyoxyalkylene groups can be used. Here, examples of the polyoxyalkylene group include a polyoxyethylene group, a polyoxypropylene group, and a polyoxybutylene group. As the auxiliary active agent (D) in the present invention,
Compounds having a polyoxybutylene / polyoxyethylene / polyoxypropylene group such as polyoxybutylene / polyoxyethylene / polyoxypropylene glyceryl ether, polyoxybutylene / polyoxyethylene / polyoxypropylene diethyl ether;
Polyoxypropylene / polyoxyethylene copolymer dimethyl ether;
Polyoxyethylene / polyoxypropylene glycol;
Examples include polyoxypropylene / polyoxyethylene copolymer dialkyl ethers such as polyoxypropylene / polyoxyethylene copolymer diethyl ether. In addition, the polyoxyalkylene derivative which has multiple types of polyoxyalkylene group used by this invention can be manufactured by a well-known method. For example, polyoxypropylene / polyoxyethylene random copolymer dialkyl ether is obtained by addition polymerization of ethylene oxide and propylene oxide to a compound having a hydroxyl group, and then ether reaction of alkyl halide in the presence of an alkali catalyst. It is done.

  Among these auxiliary activators (D), polyoxybutylene / polyoxyethylene / polyoxypropylene glyceryl ether, polyoxybutylene / A compound having a polyoxybutylene / polyoxyethylene / polyoxypropylene group such as polyoxyethylene / polyoxypropylene diethyl ether is preferred.

  The amount ratio of the organic phase and the activator phase used in the present invention is not particularly limited. However, since it is generally easy to obtain a one-phase microemulsion composition, the organic phase / active agent phase is 3 / It is preferable to mix within a ratio of 7 to 9.5 / 0.5, more preferably 5/5 to 9/1.

  Further, the ratio of the nonionic surfactant (C) and the co-active agent (D) in the active agent phase is not particularly limited, but in general, it is easy to form a one-phase microemulsion. The ratio is preferably 1/9 to 9/1, more preferably 3/7 to 7/3.

<Water component (E)>
The water component (E) in the method for producing photochromic fine particles of the present invention is an essential component for forming an emulsion composed of an organic phase and an aqueous phase.

  As the water component in the production method of the present invention, in addition to water itself such as distilled water and ultrapure water, a compound having an effect of promoting emulsion formation such as lowering the interfacial tension or raising the cloud point of the surfactant is added. It may be an additive-containing aqueous solution. As a compound having an effect of promoting emulsion formation by addition to water, for example, a compound having a polyvalent hydroxyl group such as 1,3-butanediol can be used.

  Although the compounding quantity of the water component (E) used with the manufacturing method of the photochromic fine particle of this invention is not specifically limited, The kind of (A)-(C) used when producing | generating a one-phase microemulsion. The blending amount may be appropriately adjusted according to the amount and blending amount and other additives so as to be within the region where the one-phase microemulsion is formed, and usually 10 to 90 mass of the entire one-phase microemulsion composition. %.

<Other ingredients>
In the method for producing photochromic fine particles of the present invention, in addition to the above components, a polymerization curing accelerator (G), a low polarity organic solvent (H), a thickener (F1), and a hydrotrope agent (F2) may be used. Is possible. Hereinafter, these components will be described.

<Thickener (F1)>
In the method for producing photochromic fine particles of the present invention, a thickener can be used to increase the viscosity and facilitate the formation of a one-phase microemulsion or O / W nanoemulsion.

  Specific examples of thickeners that can be used in the present invention include gum arabic, arginine carbomer (carboxyvinyl polymer), sodium alginate, propylene glycol alginate, ethyl cellulose, sodium carboxymethylcellulose, xanthan gum, synthetic sodium silicate / magnesium Dimethyl distearyl ammonium hectorite, cyclodextrin, sodium polyacrylate / sodium polyacrylate, coconut oil fatty acid-amidopropyldimethyl-aminoacetic acid betaine 30 wt% aqueous solution, acrylic emulsion thickener and the like.

  The hydrotrope agent (F2) mentioned above can be used alone or in combination of two or more, but the amount used thereof is, for example, 0 to 30 parts by mass, particularly 1 to 15 parts per 100 parts by mass of the activator phase. It is preferable to use in the range of parts by mass.

<Hydrotrope (F2)>
The hydrotrope agent in the method for producing photochromic fine particles of the present invention is an agent that forms a liquid crystal by being aligned with a surfactant. By adding such a hydrotope agent, the stability of the organic phase-water phase interface is improved, the temperature stability is improved, and the expression range of bicontinuous microemulsions and O / W nanoemulsions is expanded. There is.

Specifically as the hydrotrope agent (F2) that can be used in the present invention,
Lower alcohols such as ethanol, isopropyl alcohol and glycol ether;
Polyhydric alcohols such as glycerin, propylene glycol, hexylene glycol, 1,2-octanediol;
Nonionic surfactants such as polyethylene glycol type / polyhydric alcohol type;
Anionic surfactants such as sulfonates;
urea;
Etc.

  The hydrotrope agent (F2) mentioned above can be used alone or in combination of two or more, but the amount used thereof is, for example, 0 to 20 parts by mass, particularly 1 to 10 parts per 100 parts by mass of the activator phase. It is preferable to use in the range of parts by mass.

<Polymerization curing accelerator (G)>
In the method for producing photochromic fine particles of the present invention, when an O / W nanoemulsion composition containing a polymerizable monomer (A) is polymerized to produce fine particles, depending on the type of the polymerizable monomer (A), Various polymerization curing accelerators can be used in order to accelerate polymerization curing rapidly. For example, when a radical polymerizable monomer is used, a radical polymerization initiator is used as a polymerization curing accelerator.

  There is no restriction | limiting in particular in the timing which adds a polymerization hardening accelerator (G), You may add to the organic phase containing a polymerizable monomer (A) from the beginning, and may add after O / W nanoemulsion formation.

  Also, when OH group, SH group, NH2 group, NCO group or NCS group is introduced as a polymerizable functional group in the polyaddition monomer, a reaction catalyst or condensing agent for urethane or urea is a polymerization curing accelerator. Used as.

As a radical polymerization initiator using a radical polymerizable monomer,
Diacyl peroxides such as benzoyl peroxide and decanoyl peroxide;
peroxyesters such as t-butylperoxy-2-ethylhexanate, t-butylperoxyneodecanate;
Percarbonates such as diisopropyl peroxydicarbonate, di-sec-butylperoxydicarbonate;
2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis (2,4-dimethylvaleronitrile) (V65), 2,2′-azobis (4-methoxy-2,4- Dimethylvaleronitrile) (V70), 1,1′-azobis (cyclohexane-1-carbonitrile) (V65), 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride ( VA-044), azo compounds such as 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropioamidine] n-hydrate (VA-057);
Inorganic peroxides such as potassium persulfate;
Etc. can be used.

  If necessary, a polymerization initiator using a radical polymerizable monomer can be used in combination with a cocatalyst such as iron (III) chloride.

As a reaction catalyst used when a polyaddition monomer is used in the present invention,
Amine-based catalysts such as triethylenediamine and 1,8-diazabicyclo- (5,4,0) -7-undecene;
Tin-based catalysts such as dibutyltin bis (isooctylthioglycolate) and dioctyltin dichloride;
Metals such as copper oleate and iron acetylacetonate;
Etc. can be used. As a condensing agent,
Inorganic salts such as hydrogen chloride and sulfuric acid;
organic acids such as p-toluenesulfonic acid and camphorsulfonic acid;
Acidic ion exchange resins such as amberlite and amberlist;
Carbodiimides such as dicyclohexylcarbodiimide;
Etc. can be used.

  Each of the various polymerization curing accelerators (G) described above can be used alone or in combination of two or more, but the amount used can be a so-called catalytic amount, and usually the polymerizable monomer (A). A range of 0.001 to 30 parts by weight, particularly 0.01 to 5 parts by weight per 100 parts by weight is sufficient.

<Low water-soluble organic solvent (H)>
In the method for producing photochromic fine particles of the present invention, by using a low water-soluble organic solvent (H) that is soluble in the photochromic compound (B) and difficult to dissolve in water, the inclusion amount of the photochromic compound in the fine particles is improved. I can do it.

  As the low water-soluble organic solvent (H) that can be used in the present invention, an organic solvent having a water solubility (20 ° C.) of 3 parts by mass or less of water and a relative dielectric constant of 10 or less with respect to 100 parts by mass of the organic solvent. It is preferable to use a solvent. Specific examples of the low water-soluble organic solvent (H) include halogen solvents such as methylene chloride and chloroform, and aromatic solvents such as toluene and xylene.

Furthermore, in the production method of the present invention, various compounding agents, for example, an ultraviolet absorber, an infrared absorber, an ultraviolet stabilizer, an antioxidant, an anti-coloring agent, an antistatic agent, a fluorescent dye, as long as the effects of the present invention are not impaired. Various stabilizers such as dyes, pigments and fragrances, additives, solvents and the like can be blended as necessary.
Next, a method for producing the photochromic fine particles of the present invention using the above components will be described.

<Method for producing photochromic fine particles>
<Step of obtaining a one-phase microemulsion composition>
In the method for producing photochromic fine particles of the present invention, first, a polymerizable monomer (A), an organic phase containing a photochromic compound (B), a nonionic surfactant (C) and a co-active agent (D) are included. An activator phase and an aqueous phase containing an aqueous component (E) are mixed to produce a one-phase microemulsion composition. At this time, a thickener (F1), a hydrotrope agent (F2), polymerization is performed as necessary. A hardening accelerator (G), a low water-soluble organic solvent (H), etc. can also be added. The order of addition of these components is not particularly limited, and all components can be mixed simultaneously.

In the method for producing photochromic fine particles of the present invention, as a method for forming a one-phase microemulsion after mixing the above components, a method of adding a water component (E) after forming a W / O emulsion (PIC method, Phase composition emulsification method) and methods (PIT method, phase inversion temperature emulsification method) of giving a temperature stimulus such as temperature rise or temperature drop after formation of O / W or W / O emulsion, respectively, A method can also be adopted. In either method, the formation of the single-phase microemulsion is because when the single-phase microemulsion is formed from the white turbid W / O emulsion, the liquid turbidity becomes small and in some cases becomes a translucent liquid. The formation of the phase microemulsion can be confirmed visually.
Hereinafter, the formation procedure of the said one-phase microemulsion composition is demonstrated.

<Phase inversion composition emulsification method (PIC method)>
A one-phase microemulsion composition is formed by adding an aqueous component (E) (hereinafter also referred to as an aqueous phase) to a mixture of an organic phase and an activator phase. As a method for adding the aqueous phase, the water component (E) may be gradually added to the above mixture, or a predetermined amount of the water component (E) may be added to the mixture all at once. The amount of water component (E) added until a one-phase microemulsion is formed is usually about 10 to 90 parts by mass when the total of the organic phase, the activator phase and the aqueous phase is 100 parts by mass. Although the temperature at the time of addition does not have a restriction | limiting in particular, Usually, it can carry out by room temperature vicinity. Moreover, general methods, such as using a magnetic stirrer and a stirring blade, can be used for stirring, and the stirring speed should just employ the conditions with which a mixture is fully stirred.

  When the water component (E) is gradually added to the mixture, first, reverse micelles (O / W emulsion) are formed. Further, by adding the water component (E), a W / O emulsion and then a bicontinuous single-phase microemulsion are formed. The formation of the single-phase microemulsion can be confirmed by the fact that the liquid becomes less turbid and in some cases becomes a translucent liquid.

<Phase inversion temperature emulsification method (PIT method)>
In the phase inversion temperature emulsification method, first, a water component (E) is added to a mixture of an organic phase and an activator phase to obtain a W / O or O / W emulsion. Next, a bicontinuous single-phase microemulsion can be obtained by applying a temperature stimulus such as a temperature increase in the case of an O / W emulsion and a temperature decrease in the case of a W / O emulsion. Although the temperature at the time of addition does not have a restriction | limiting in particular, Usually, it can carry out by room temperature vicinity. Moreover, general methods, such as using a magnetic stirrer and a stirring blade, can be used for stirring, and the stirring speed should just employ the conditions with which a mixture is fully stirred. The degree of temperature change required to form a one-phase microemulsion varies depending on the type and amount of organic phase and activator phase used, but is generally in the range of 20-100 ° C.

  The formation of the one-phase microemulsion from the W / O or O / W emulsion can be confirmed by the fact that the liquid turbidity becomes small and in some cases becomes a translucent liquid.

<Step of obtaining O / W nanoemulsion>
In the method for producing photochromic fine particles of the present invention, an O / W nanoemulsion is formed from a one-phase microemulsion composition obtained by a PIC method or a PIT method. An O / W nanoemulsion can be obtained by further adding a water component (E) to the one-phase microemulsion composition.

  The formation of an O / W nanoemulsion can be confirmed because white turbidity is produced by the addition of the water component (E). Although there is no restriction | limiting in particular about the temperature of the water component (E) to add, Usually, the thing near room temperature is used. Moreover, general methods, such as using a magnetic stirrer and a stirring blade, can be used for stirring, and the stirring speed should just employ the conditions with which a mixture is fully stirred. In addition, you may add a polymerization hardening accelerator (G) before the addition of a water component (E) or after addition as needed.

  Moreover, the ratio of the content of each composition in the preparation process of the composition of the O / W nanoemulsion depends on the type, but the organic phase is 1 to 50% by mass and the activator phase is 1 to 50% by mass. If the aqueous phase is in the range of 20 to 99% by mass, an O / W nanoemulsion phase is easily formed.

<Process to polymerize>
In the method for producing photochromic fine particles of the present invention, after obtaining an O / W nanoemulsion by the above method, the nanoemulsion is polymerized to produce photochromic fine particles.

  Polymerization and curing for producing photochromic fine particles are radical polymerization, ring-opening polymerization, anionic polymerization or condensation polymerization by irradiation with active energy rays such as ultraviolet rays, α rays, β rays, and γ rays, heat, or a combination of both. It is done by doing. That is, an appropriate polymerization means may be employed depending on the type of the polymerizable monomer (A) or polymerization curing accelerator (G) and the form of the photochromic fine particles to be formed.

  When the O / W nanoemulsion is thermally polymerized, it particularly affects the properties of the photochromic fine particles from which the temperature during thermal polymerization is obtained. Since this temperature condition is influenced by the type and amount of the thermal polymerization initiator and the type of the polymerizable monomer, it cannot be generally limited, but generally a method of performing polymerization at a constant temperature is suitable. Since the polymerization time varies depending on various factors as well as the temperature, it is preferable to determine the optimal time according to these conditions in advance. Generally, the conditions are set so that the polymerization is completed in 2 to 100 hours. It is preferable to choose.

  In addition, when the O / W nanoemulsion is photopolymerized, among the polymerization conditions, the properties of the photochromic fine particles from which the intensity of irradiated light is obtained are particularly affected. This illuminance condition is influenced by the type and amount of the photopolymerization initiator and the type of the polymerizable monomer (A), and thus cannot be generally limited. However, generally, UV light of 50 to 500 mW / cm 2 is applied at a wavelength of 365 nm. It is preferable to select conditions so that light is irradiated in a time of 0.5 to 10 minutes.

<Subsequent processing>
In the composition containing the photochromic fine particles obtained by the method for producing photochromic fine particles of the present invention, there are non-polymerized components such as a nonionic surfactant and a co-active agent in addition to the fine particles. Therefore, it is possible to remove each component by performing a purification treatment. The method for purifying the photochromic fine particles is not particularly limited, but considering that the photochromic fine particles are nano-order fine particles, a method of separating the particle component and the liquid component by centrifugation is preferable. The separated particle component can be further purified by adding water and / or an organic solvent and centrifuging to remove the remaining unpolymerized component.

  Subsequently, liquid components can be removed from the obtained fine particles by, for example, freeze-drying, but the fine particle dispersion may be used as it is without removing the solvent.

<Photochromic fine particles>
The photochromic fine particles obtained by the production method of the present invention contain a photochromic compound inside particles composed of a polymer of a polymerizable monomer, and the particle size is as small as 20 to 400 nm. For this reason, it is easy to disperse | distribute to a solution, a base material, etc. Moreover, since it is below the wavelength of visible light, when used for optical uses, such as a plastic lens base material, it has the characteristics that high transparency is acquired.

  The photochromic fine particles of the present invention can be used as a powder solid, but can be used by being dispersed in a solution, a plastic lens base material or the like depending on the application. The photochromic fine particles of the present invention described above can exhibit photochromic properties with excellent color density, fading speed, etc., and also have an optical substrate imparted with photochromic properties without reducing properties such as mechanical strength. It is effectively used for producing a material such as a photochromic lens.

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples.
Each component used in this example will be described.

[Polymerizable monomer (A)]
A1: EGDMA: Ethylene glycol dimethacrylate [Photochromic compound (B)]
B1: 9-bicyclononylidene-3H-naphtho [1,2-b] pyran [nonionic surfactant (C)]
C1: UNIOX ST-30IS (manufactured by NOF Corporation: polyisoethylene stearic acid polyoxyethylene sorbit). HLB value = 11.1.
C2: Span 80 (manufactured by Wako Pure Chemical Industries: Sorbitan monooleate). HLB value = 4
. 3
[Co-active agent (D)]
D1: Willbride S-753 (NOF Corporation): polyoxybutylene / polyoxyethylene / polyoxypropylene glyceryl ether [water component (E)]
E1: distilled water E2: 1,3-BG aqueous solution: aqueous solution containing 50% 1,3-butanediol E3: aqueous solution of PVA: aqueous solution containing 10% polyvinyl alcohol (degree of polymerization 500) [Thickener (F1)]
F1-1: Nissan Anon BDF (registered trademark) -SF (manufactured by NOF Corporation): palm oil fatty acid-amido propyldimethyl-aminoacetic acid betaine 30 wt% aqueous solution [hydrotrope agent (F2)]
F2-1: 1,2-OD (manufactured by Tokyo Chemical Industry): 1,2-octanediol [polymerization curing accelerator (G)]
G1: V65 (manufactured by Wako Pure Chemical Industries): 2,2′-azobis (2,4-dimethylvaleronitrile)
[Low water-soluble organic solvent (H)]
H1: DCM: dichloromethane H2: DCE: dichloroethane

Example 1 (Production example by PIC method)
17.28 g of nonionic surfactant C1 as an activator phase, 25.92 g of auxiliary activator D1, 0.7 g of photochromic compound B1, and 1.8 g of hydrotrope agent F2-1 are mixed and polymerized as an organic phase. 4.26 g of the polymerizable monomer A1, 0.04 g of the polymerization curing accelerator G1, and 1300 g of the water component E as an aqueous phase were mixed to prepare each. (The mixing ratio (mass ratio) of each component is nonionic surfactant / co-active agent = 4 / 6.active agent phase / organic phase = 9/1).

  Thereafter, the activator phase and the organic phase were mixed and stirred in a 200 ml tall beaker using a magnetic stirrer. Furthermore, distilled water was added little by little while continuing stirring, and sampling was performed appropriately according to the amount added, and the phase was visually observed. When 50 g of distilled water was added to the mixed solution that had become cloudy due to the addition of distilled water, the turbidity became thin and translucent with the formation of a single-phase microemulsion (bicontinuous microemulsion).

  Further, distilled water was added, and a total of 200 g of distilled water (water content of 90% by mass with respect to the total amount of the composition) was added, whereby an O / W nanoemulsion was formed and white turbidity was generated in the liquid.

  The obtained O / W nanoemulsion solution was put into a 300 ml separable flask, and a polymerization reaction was carried out at 45 ° C. for 48 hours while stirring the stirring bar at 400 rpm. Then, centrifugation was performed 5 times on the conditions of 14,000 rpm and 15 minutes using the centrifuge (H-200nR by domestic centrifuge Co., Ltd.), and it wash | cleaned with distilled water. Further, after preliminary freezing with liquid nitrogen, freeze drying was performed for 24 hours with a freeze dryer (FD-1000 manufactured by EYELA), and 0.93 g of a solid (polymer material) was recovered (recovery rate: 18.8%). ).

When morphological observation of the obtained fine particles was performed using a scanning electron microscope (SEM, manufactured by Hitachi, Ltd., model: S-3000N), it was confirmed that fine particles having an average particle size of 94 nm were generated.
The theoretical inclusion rate of the phorchromic compound in the phorchromic fine particles was 14%, the inclusion rate was 3.0%, and the inclusion efficiency was 4.0%.

  Here, the recovery rate was calculated by dividing the recovered amount (g) of fine particles by the weight (g) of the organic phase charged (hereinafter excluding the organic solvent).

The theoretical inclusion rate, inclusion rate, and inclusion efficiency are values calculated by the following method.
The theoretical inclusion rate is the follow when the total mass of the polymer material containing the photochromic compound is 100% in the ideal case where the total amount of the added photochromic compound is contained in the polymer material containing the polymerizable monomer. It is the amount of the chromic compound and is expressed in mass%.

  The encapsulation rate and the encapsulation efficiency were calculated as follows. First, the amount of photochromic compound inclusion in the fine particles was quantified. That is, 0.05 g of the prepared fine particles was added to 25 ml of acetonitrile. Then, the ultrasonic wave was irradiated for 60 minutes, the photochromic compound was extracted, and it was set as the sample for a measurement. This sample was measured using a UV / VIS spectrophotometer (manufactured by Shimadzu Corporation, model: UV-1700) together with a standard containing a certain amount of photochromic compound, and the amount of photochromic compound contained per gram of photochromic fine particles ( g / g) was calculated. Based on the obtained amount of encapsulation, the encapsulation rate and the encapsulation efficiency were calculated by the following formulas.

Inclusion rate (%) = (recovered amount of photochromic fine particles (g) × encapsulated amount of photochromic compound (g / g)) / (recovered amount of photochromic fine particles (g)) × 100
Encapsulation efficiency (%) = (recovered amount of photochromic fine particles (g) × encapsulated amount of photochromic compound (g / g)) / (charged photochromic compound (g)) × 100

Examples 2 to 4 (Production Examples by PIC Method)
Except that the amount and amount of each component used in the activator phase, organic phase and aqueous phase were used as shown in Table 1, the same operation as in Example 1 was carried out, and after forming the O / W nanoemulsion, the solid was added. It was collected.
The characteristics of the polymer material containing the obtained phorochomic compound are shown in Table 2 together with Example 1.

  When the particle form was observed in the same manner as in Example 1, it was confirmed that fine particles of 100 nm or less could be prepared in any of the Examples.

Example 5 (Production example by PIC method)
19.61 g of nonionic surfactant C1 as an activator phase, 19.61 g of auxiliary activator D1, 0.78 g of hydrotrope F2-1, 8.52 g of polymerizable monomer A1 as an organic phase, photochromic Compound B1 (1.4 g), polymerization curing accelerator G1 (0.08 g), and water phase (E2500 g) were prepared. (Nonionic surfactant / co-active agent = 5/5. Activator phase / organic phase = 8/2). Thereafter, the activator phase and the organic phase were mixed and stirred in a 500 ml tall beaker using a magnetic stirrer. Furthermore, distilled water was added little by little while continuing stirring, and sampling was performed appropriately according to the amount added, and the phase was visually observed. When 200 g of distilled water was added to the mixed solution that had become cloudy due to the addition of distilled water, the turbidity became thin and translucent with the formation of a single-phase microemulsion (bicontinuous microemulsion). Further, distilled water was added and a total of 450 g of distilled water (water content was 83% by mass with respect to the total amount) was added, whereby an O / W nanoemulsion was formed and white turbidity was generated in the liquid. The obtained O / W nanoemulsion solution was put into a 1000 ml separable flask, and a polymerization reaction was carried out at 55 ° C. for 6 hours while stirring at 200 rpm. Then, centrifugation was performed 5 times on the conditions of 14,000 rpm and 15 minutes using the centrifuge (H-200nR by domestic centrifuge Co., Ltd.), and it wash | cleaned with distilled water. Furthermore, after pre-freezing with liquid nitrogen, lyophilization was performed for 24 hours, and 14.8 g of solid was recovered (recovery rate 148%). The recovery rate exceeded 100% because the surfactant component remained. It is thought that it is because. The obtained particles had good dispersibility, and it was confirmed that fine particles having an average particle diameter of 61 nm were generated. The theoretical inclusion rate of the phorchromic compound in the phorchromic fine particles was 14.8%, the inclusion rate was 0.046%, and the inclusion efficiency was 0.48%.

Example 6 (Production Example by PIT Method)
5.25 g of nonionic surfactant C1 and 5.25 g of auxiliary activator D1 were used as the activator phase, 3.87 g of the polymerizable monomer A1 as the organic phase, 0.63 g of the photochromic compound B1, and super as the aqueous phase 15 g of pure water was mixed. The obtained mixture was heated to 70 ° C. to obtain a one-phase microemulsion (bicontinuous microemulsion) composition. (The mixing ratio (mass ratio) of each component is nonionic surfactant / co-active agent = 5/5. Active agent phase / organic phase = 7/3).

  165 g of ultrapure water was added to the one-phase microemulsion (bicontinuous microemulsion) composition to obtain an O / W nanoemulsion at 27 ° C. Furthermore, 0.039 g of potassium persulfate dissolved in 5 g of distilled water was added as a polymerization hardening accelerator, and the polymerization reaction was carried out by stirring for 48 hours in a nitrogen atmosphere at 45 ° C. and blade rotation speed of 450 rpm. Thereafter, centrifugation was performed 5 times under the condition of 14,000 rpm for 15 minutes using a centrifuge (model H-200nR manufactured by Kokusan Centrifuge Co., Ltd.) and washed with distilled water. Further, after preliminary freezing with liquid nitrogen, freeze-drying was performed for 24 hours, and 2.96 g of a solid (polymer material) was recovered (recovery rate 65.1%, theoretical inclusion rate 14%, inclusion rate 1.87). %, Inclusion efficiency 8.77%)). As the obtained solid, fine particles having an average particle diameter of 98 nm were obtained.

Comparative Example 1 (Production Example by Suspension Polymerization Method)
A mixture of 0.1 g of C2 as an activator phase, 20 g of polymerizable monomer A1 as an organic phase, 2 g of photochromic compound B1, and 120 g of E3 as an aqueous phase was prepared. The obtained mixture was stirred at a high speed of 19,000 rpm for 3 minutes with a homogenizer (PORYTRON, model PT3100) to form an O / W emulsion. The mixture was added to a 500 ml jacketed separable flask equipped with a stirring blade (90 mm in diameter). The inside of the flask was kept at 60 ° C. using a circulating thermostat, and a polymerization reaction was performed for 3 hours in a nitrogen atmosphere. Thereafter, photochromic fine particles having an average particle diameter of 524 nm were collected using a centrifuge. (Recovered amount 18.7 g, recovery rate 82.6%, theoretical inclusion rate 9.1%, inclusion rate 6.5%, inclusion efficiency 60.1%)
Thus, in the case of suspension polymerization, it was necessary to use a large apparatus (homogenizer) for forming an O / W emulsion, but the particle diameter of the obtained fine particles exceeded 400 nm and was large.

Example 7 (Production of photochromic cured product)
The photochromic hardened | cured material was obtained by the kneading method using the photochromic fine particle manufactured in the said Example. The polymerization method is shown below.

  2. CR39 (allyl resin plastic lens) monomer 2.14 parts by mass (0.04 parts by mass as a photochromic compound amount) of the photochromic fine particles obtained in Example 7 in 100 parts by mass, and diisopropyl peroxydicarbonate as a polymerization initiator. 4 parts by mass was added and mixed thoroughly. This mixed solution was poured into a mold composed of a glass plate and a gasket made of an ethylene-vinyl acetate copolymer, and substantially all of the monomer composition was polymerized by cast polymerization. The polymerization was performed using an air furnace, gradually increasing the temperature from 30 ° C. to 80 ° C. over 15 hours, and maintaining at 80 ° C. for 2 hours. After the polymerization, the cured product was removed from the glass mold of the mold. As a result of evaluating the obtained photochromic cured product by the following method, the maximum absorption wavelength was 445 nm, the color density was 0.17, and the appearance evaluation was 2.

[Sample evaluation method]
1) Photochromic properties The obtained photochromic cured product (thickness 2 mm) was used as a sample, and a xenon lamp L-2480 (300W) SHL-100 manufactured by Hamamatsu Photonics Co., Ltd. was passed through an aeromass filter (manufactured by Corning). The polymer was irradiated for 120 seconds at 20 ° C. ± 1 ° C. with a beam intensity of 365 nm = 2.4 mW / cm 2 and 245 nm = 24 μW / cm 2 on the polymer surface, and the photochromic properties of the cured product were measured. Each photochromic characteristic was evaluated by the following method.

  Maximum absorption wavelength (λmax): The maximum absorption wavelength after color development determined by a spectrophotometer (instant multichannel photodetector MCPD1000) manufactured by Otsuka Electronics Co., Ltd. The maximum absorption wavelength is related to the color tone at the time of color development.

  Color density {ε (120) −ε (0)}: difference between absorbance {ε (120)} after light irradiation for 120 seconds and absorbance ε (0) before light irradiation at the maximum absorption wavelength. It can be said that the higher this value, the better the photochromic properties. Further, when the color was developed outdoors, the color tone was visually evaluated.

2) Appearance evaluation Evaluation of white turbidity in the obtained photochromic cured body was performed visually.
1: There is no cloudiness or it is hardly visible.
2: Slightly cloudy.
3: Strong cloudiness.
4: What appears to be a hardened body.

Example 8
A lens was prepared in the same manner as in Example 8, except that 1.33 parts by mass of the photochromic fine particles prepared in Example 1 (0.04 parts by mass as the photochromic compound content) were used as the photochromic fine particles.

  The obtained photochromic cured product had a maximum absorption wavelength of 445 nm and a color development density of 0.06.

Comparative Example 2
A lens was prepared in the same manner as in Example 8, except that 0.50 part by mass of the photochromic fine particle prepared in Comparative Example 1 (0.04 part by mass as the photochromic compound content) was used as the photochromic fine particle.

  The obtained photochromic cured product had a maximum absorption wavelength of 448 nm, a color density of 0.03, and an appearance evaluation of 4. In addition, the surface of the lens after color development was clearly bumpy and shaded at the time of color development.

Claims (3)

  An organic phase containing a polymerizable monomer (A) and a photochromic compound (B), an activator phase containing a nonionic surfactant (C) and a co-active agent (D), and an aqueous phase containing a water component (E) To obtain a one-phase microemulsion composition, to obtain an organic phase (O phase) / water phase (W phase) nanoemulsion from the one-phase microemulsion, and further to an organic phase (O phase) / water phase (W phase) The manufacturing method of the photochromic microparticles | fine-particles including the process of polymerizing nanoemulsion.   The method for producing photochromic fine particles according to claim 1, wherein the polymerizable monomer (A) is a radical polymerizable monomer.   Photochromic fine particles produced by the production method according to claim 1, having an average particle diameter of 20 to 400 nm and containing a photochromic compound inside a polymer of a polymerizable monomer.