JPH04344638A - Color-changing microcapsule containing material with photoresponsive film and method for controlling its color change - Google Patents

Abstract

PURPOSE:To manufacture the microcapsules having photoresponsive films at low cost from wide ranges of materials and to provide the method for easily and precisely controlling color development reaction based on interdispersion of color change materials from the inside and outside to the other sides through these films. CONSTITUTION:Bimolecular built-up films 3 containing an organic dye responding to light of wavelength nu2 to change electron transfer performance and a conformation isomerizing substance responsing to light of wavelength nu2 and being excited are buried in the thin pores 2 of the film Cf of each microcapsules MC, and a dye precursor 6 and a color developer 8 are placed in the inside and outside of the microcapsules MC, thus permitting the bimolecular built-up films 3 to be elevated in material permeability by irradiating with the lights R1 and R2 (wavelengths of nu1 and nu2), the dye precursor 6 and the color developer 8 can both sides to be interdispersed to the other sides through the films 3 and the color to be developed.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD OF THE INVENTION This invention relates to a color-changing microcapsule-containing material having a photoresponsive composite membrane whose substance permeability can be controlled by optical stimulation, and a method for controlling color change thereof. This invention relates to a color-changing microcapsule-containing material that utilizes the photoresponsiveness of a conformational isomerizable substance and an organic dye, and a method for controlling its color change.

0002

[Prior art and its problems] In recent years, synthetic polymer membranes that have separation of substances at the molecular level and selective permeation functions have attracted attention. something is proposed. As a method of imparting the above-mentioned functions to a polymer membrane, attempts have been made to chemically modify a synthetic polymer membrane or to make it into some kind of composite. Function control methods include temperature change, light irradiation, ultrasonic irradiation, electric field, redox,
There are pH changes, etc. Specifically, ``introducing functional groups or isomerizable groups into polymer side chains'', ``immobilizing bilayer membranes on polymer membranes'', ``using graft polymers as surface treatments'', etc. There are methods such as "using polymer gel."

On the other hand, there have been attempts to impart the above-mentioned substance permeation function to microcapsules. Here, a microcapsule is a minute container with a diameter of several microns to several hundred microns, and is used as a packaging material for ink or medicine. The substance sealed inside the container is protected from the outside environment by the capsule membrane that constitutes the container. The capsule membrane of such microcapsules is formed with a polymer membrane, and as in the case of the functional polymer membrane described above,
Attempts have been made to impart a substance permeation function by chemically modifying the capsule membrane. For example, by forming a bimolecular lamella layer inside a porous polymer capsule membrane, or by graft polymerizing a linear polymer onto the surface of a polymer wall membrane, the internal phase substance of the capsule can be permeated to the outside of the capsule. There are examples of this. As in the case of the polymer membrane mentioned above, means for controlling the permeation rate of the substance in the capsule internal phase include temperature change, light irradiation, ultrasonic irradiation, electric field, redox, pH change, etc., and these can be adjusted. It is known that the above-mentioned bilayer membranes and graft polymers function as a kind of molecular valve.

FIG. 12 schematically shows an example of a microcapsule whose substance permeability is controlled by light irradiation. The capsule membrane Cf of the microcapsule MC is made of a porous polymer material, and a bilayer membrane F1 forming a lamellar layer is embedded in the pores H thereof. As shown in the partially enlarged view showing the pores, the bilayer membrane F1 is made of an amphipathic compound,
Lipid F2 containing an azobenzene group is mixed therein as a photoisomerizable substance. Liquid substances Mi and Mo are arranged on the inside (capsule inner phase) and the outside (capsule outer phase) of the capsule membrane Cf, respectively.

It is known that when a microcapsule-containing material having the above-mentioned structure is irradiated with ultraviolet rays, the substance permeability of the capsule membrane Cf increases, and when it is irradiated with visible light that does not contain ultraviolet rays, the original substance permeability is restored. It is being This is because the azobenzene groups in the photoisomerizable substance F2 dispersed and associated in the bilayer film F1 change from the linear trans type to the bent cis type due to ultraviolet irradiation, resulting in two ordered molecules in which the molecules are arranged in an orderly manner. This is considered to be because the film structure of the film F1 is disturbed. By irradiation with visible light, the azobenzene group returns to its original trans form, and the bilayer film F1 regains its ordered film structure. In this case, the azobenzene group is not placed in the bilayer membrane F1 part, but
If it is incorporated into the wall W portion of the capsule membrane Cf by covalent bonding, even if it is irradiated with ultraviolet rays and visible light as described above,
Substance permeability hardly changes. From this, it is considered important that the photoisomerizable molecules exist in the fluid bilayer membrane F1 portion.

However, the capsule membrane of a microcapsule is required to have a delicate photoresponsive function as described above, and the types of photoisomerizable substances that meet such requirements are naturally limited. Therefore, when applying microcapsule-containing substances to a color-changing reaction, the types of substances that can be used as photoresponsive membrane materials to be dispersed and associated in the capsule membrane are limited, and color-changing microcapsules containing the desired quality are limited. It becomes difficult to manufacture things cheaply.

[0007]

OBJECTS OF THE INVENTION The present invention has been made in view of the problems of the prior art described above, and it is possible to easily form desired color-changing microcapsules using inexpensive materials since there is a wide selection range of photoresponsive film materials. It is an object of the present invention to provide an inexpensive color-changing microcapsule-containing material that can be produced and whose color-changing reaction can be easily and precisely controlled, and a method for controlling its color change.

[0008]

[Summary of the Invention] There are two main points of this invention, one of which is that the above-mentioned purpose is to provide a microcapsule-containing material containing microcapsules consisting of a capsule membrane that changes substance permeability upon irradiation with light. wherein the capsule membrane has a bimolecular membrane containing a conformational isomerizing substance that changes its three-dimensional structure through a redox reaction and an organic dye having spectral sensitizing properties, and the capsule membrane has an inner phase and an outer phase. A dye precursor is placed on one side and a color developer is placed on the other side.
A color comprising a photoresponsive film, characterized in that the molecular film increases substance permeability when irradiated with light of a specific wavelength, and the dye precursor and the color developer mutually diffuse and mix to form a color. This is achieved by providing variable microcapsule contents.

Another point of the main point of the present invention is that the above-mentioned object is to change the permeability of a material by receiving light of a specific wavelength.
It contains a microcapsule consisting of a capsule membrane with a molecular membrane, a dye precursor is placed in one of the inner phase and an outer phase of the capsule membrane, and a color developer is placed in the other, and the bilayer membrane undergoes an oxidation-reduction reaction. Contains a conformational isomerizable substance that changes the three-dimensional structure and an organic dye with spectral sensitizing properties.
A method for controlling the color change of a color-changing microcapsule-containing substance with photoresponsiveness that changes its molecular three-dimensional structure and increases substance permeability when irradiated with light at a specific wavelength, and is in a state of low substance permeability. When the capsule membrane is irradiated with light of the specific wavelength to increase substance permeability, the amount of irradiation of the light of the specific wavelength is adjusted to form microcapsules by mutual diffusion of the dye precursor and the color developer. This point is achieved by providing a method for controlling the color change of a color-changing microcapsule containing material, which is equipped with a photoresponsive film and is characterized by controlling the color change of the entire containing material.

0010

[Embodiments of the Invention] This invention will be described below in the first to fourth embodiments.
This will be explained in detail based on examples. <First Example> Figure 1 shows the structure of a color-changing polymer microcapsule containing material as a first example and a method of controlling a coloring reaction based on substance diffusion through the capsule membrane by light irradiation (hereinafter referred to as color change reaction). FIG. 2 is a schematic explanatory diagram showing the concept of a change control method. Capsule membrane C of microcapsule MC
The wall material 1 constituting f is made of a porous material and has many fine pores 2. In this example, a synthetic polymer material is used as the material for the wall material 1, and the porous sponge-like wall material 1
has been formed. The film thickness of the wall material 1 is several tens of microns (μm
) to several tens of nanometers (nm). As the polymer material forming the wall material 1, general polymer materials such as polyamide, polyester, polyurethane, polymethyl methacrylate, polyurea, polystyrene, polyvinyl alcohol, etc. can be suitably used.

[0011] Inside the pores 2 of the wall material 1, a bimolecular cumulative film 3 made of an amphipathic compound is embedded. This bimolecular cumulative film 3 can be produced by a simple method of precipitation, which will be described later, and the layered structure obtained at this time is a multilayered lamellar layer as shown in FIG. Further, the bimolecular cumulative film 3 of this example has a phase transition temperature at which it transitions from a liquid crystal state to a crystalline state set low so that it becomes a liquid crystal state with a certain degree of fluidity at room temperature. In this way, by closing the fine pores 2 of the microcapsules MC with the bimolecular cumulative film 3, it is possible to provide a high permeation barrier property even to substances with a low molecular weight.

The molecules constituting the bimolecular cumulative film 3 are as follows:
For example, phospholipids

[0013]

[Chemical formula 1]

[0014]

[Case 2]

Examples of dialkyl compounds include:

[0016]

[Chemical formula 3]

[0017]

[C4]

[0018]

[C5]

[0019]

[C6]

[0020]

[C7]

Examples of trialkyl compounds include:

0022
]

[Chemical formula 8]

Examples of liquid crystal monoalkyl compounds include:

0
024]

[Chemical formula 9]

Examples of fluorocarbon compounds include:

00
26]

[Chemical formula 10]

Various amphiphilic compounds can be used, such as:

As shown in FIG. 2, in the bimolecular cumulative film 3,
Conformationally isomerized substances 4 are dispersed and associated. The conformational isomerization substance 4 is a substance that changes the three-dimensional structure of a molecular chain by a redox reaction. As the conformational isomerization substance 4, a ferrocene compound shown in FIG. 3 is preferably used. In FIG. 3, when the ferrocene compound is oxidized, the alkyl long chain portion having a ferrocene group undergoes a large conformation change, resulting in a molecular form in which the alkyl long chain portion is bent. When the ferrocene compound in this bent conformation is reduced, it returns to its original linear conformation. Note that the conformational isomerization substance 4 is not limited to the above-mentioned ferrocene compound, and various substances having similar conformational isomerization properties can be used.

As shown in FIG. 4 [a], the bimolecular cumulative film 3
The conformationally isomerized substance 4 dispersed in the layer assumes a linear conformation under the influence of the regular molecular arrangement state of the bimolecular cumulative film 3 forming a lamellar layer, and the bimolecular cumulative film 3 as a whole assumes a linear conformation. It has a dense layered structure.

As shown in FIG. 2, an organic dye 5 having spectral sensitization properties is dispersed and associated in the bimolecular cumulative film 3. As a result, the bimolecular cumulative film 3 is irradiated with light of a specific wavelength to which the organic dye 5 is sensitive, and its electrical properties change significantly, making electron transfer possible. In addition, organic dye 5 is
Assemble with specific regularity in the molecular cumulative film 3 (for example, J
It is known that if the two molecules are allowed to associate with each other, the spectral absorption spectrum of the bimolecular cumulative film 3 as a whole is significantly shifted to the longer wavelength side.

[0031] As the above-mentioned organic dye 5,

003
2]

[Chemical formula 11]

[0033]

[Chemical formula 12]

[0034]

[Chemical formula 13]

Cyanine dyes such as ##STR6## are preferred. When a cyanine dye is associated with the bimolecular cumulative film 3 as the organic dye 5, as shown in FIG. 2, the cyanine dye 5 tends to associate between hydrophilic groups in the bimolecular cumulative film 3. be.

Returning to FIG. 1, the capsule membrane Cf of the microcapsule MC is made of an amphiphilic material in which a conformational isomerizable substance is dispersed and associated within the micropores 2 of the wall material 1 made of a polymeric substance, as described above. It has a composite structure in which a bimolecular cumulative film 3 made of a chemical compound is embedded. This capsule membrane Cf
The film thickness is as thin as several tens of microns to several tens of nanometers, and the wall material 1 of the polymer material that forms the framework of the film and the bimolecular cumulative film 3
By making the optical refractive index sufficiently close to that of the amphiphilic compound constituting the capsule film Cf, the capsule film Cf becomes substantially transparent. Therefore, the color of the microcapsule MC is the capsule membrane Cf
It appears to be the color of the capsule inner phase substance (core substance) that exists in the inner phase (internal phase).

A dye precursor 6 is arranged in the inner phase of the microcapsule MC. The dye precursor 6 is normally colorless, but is a pigment that develops color when it reacts with an acidic substance. As such substances, leuco dyes are widely known, and among them, common phthalide dyes, fluoran dyes, triphenylmethane dyes, phenothiazine dyes, and spiropyran dyes can be suitably used. in particular,
Crystal violet lactone, carbazolyl blue, indolyl red, pyridine blue, rhodamine B lactam, malachite green, 3-dialkylamino-7-, widely used in general pressure-sensitive paper and thermal paper, etc.
Examples include dialkylaminofluorane, benzoylleucomethylene blue, and the like.

In addition, various auxiliary substances 7 for adjusting the chemical properties of the dye precursor 6 are also arranged in the capsule inner phase. For example, when the dye precursor 6 is a leuco dye,
As the auxiliary substance 7, organic solvents such as distilled water, benzene, toluene, alkylnaphthalene, biphenyls, and paraffins, which are solvents for dissolving and dispersing the leuco dye, can be used. Furthermore, various commercially available waxes and resin polymers are mixed in to impart appropriate viscosity to the capsule internal phase solution.

As described above, the microcapsules MC are constructed by encapsulating the capsule inner phase material, which is a mixture of the dye precursor 6, its auxiliary substance 7, and other substances, in the inner phase of the capsule membrane Cf. be.

[0040] Here, a method for manufacturing the above-mentioned microcapsules MC will be explained. First, a microcapsule intermediate is produced in which a capsule inner phase material containing a dye precursor is encapsulated in a shell-like wall material. As a method for producing this intermediate, an interfacial polymerization method, an in-situ polymerization method, a coacervation method, etc. can be used.

Next, an alkane solution in which the amphiphilic compound and the conformational isomerizable substance of the bimolecular cumulative film material are dissolved is heated, and the above-mentioned microcapsule intermediate is poured into this solution. When left to cool naturally for several minutes, a bimolecular film is precipitated at the interface between the aqueous phase containing the capsule internal phase substance in the wall material and the alkane phase outside the wall material, and the 2 molecules accumulated in the micropores of the wall material are separated. The molecular membrane is embedded. Furthermore, it is also possible to form a bimolecular cumulative film in advance in the micropores of the wall material with an amphiphilic compound and adsorb the conformationally isomerized substance to this. can be embedded in.

Next, the microcapsules in which the bimolecular cumulative film is embedded are immersed in an aqueous solution in which an organic dye is dispersed and mixed to adsorb the organic dye to the bimolecular cumulative film, and then extracted and washed. microcapsules are completed.

In FIG. 1, a color developer 8 is arranged on the outer phase of the microcapsules MC. The color developer 8 is a substance that has the function of chemically reacting with the dye precursor 6 described above to cause it to develop color. As the color developer for the leuco dye, phenols such as α-naphthol, β-naphthol, and bisphenol A, acidic substances such as zinc salicylate derivatives, and metal salts of aromatic carboxylic acids can be used.

Further, in the capsule outer phase, various auxiliary substances 9 for adjusting the physical properties of the color developer 8 and a viscosity adjusting substance (not shown) are also mixed, as in the inner phase. As the auxiliary substance 9, organic solvents such as distilled water, benzene, toluene, alkylnaphthalene, biphenyls, and paraffins, which are solvents for dissolving and dispersing the color developer 8, can be used. Various commercially available waxes and resin polymers can be used as the viscosity adjusting substance for imparting appropriate viscosity to the capsule outer phase solution. In this way, a capsule outer phase solution is prepared by mixing and dispersing the color developer 8, its auxiliary substance 9, and other viscosity adjusting substances, and the microcapsules MC are arranged in this capsule outer phase solution. An example microcapsule content is constructed.

[0045] The microcapsule-containing material having the above-mentioned structure is put into a transparent container 10, and outside of this container 10 there is a first
A light source 11 and a second light source 12 are respectively arranged. The first light source 11 emits first light R1 including component light having a wavelength ν1 to which the organic dye in the bimolecular cumulative film 3 is sensitive. Therefore,
By controlling the irradiation of the first light R1, electron mobility in the bimolecular cumulative film 3 can be controlled. The second light source 12 includes two
Second light R2 containing component light having a wavelength ν2 that excites the conformationally isomerized substance 4 in the molecular accumulation film 3 is irradiated. Note that each of the lights R1 and R2 is preferably monochromatic light.

Next, a method for controlling the color change of the microcapsule-containing material constructed as described above will be explained with reference to FIG. In FIG. 5, a transparent container 10 contains the microcapsule-containing material of this example, which is a mixture of microcapsules MC containing a dye precursor 6, a color developer 8, and its auxiliary substances. . thermally stable initial state stage (ST1
), as shown in FIG. 4 [a], the conformational isomerizable substance 4 dispersed and associated in the bimolecular cumulative film 3 is
It has a stable molecular form that relieves the surface pressure of the bimolecular cumulative film 3. In this example, a ferrocene compound is used as the conformational isomerization substance 4. In the initial state, this ferrocene compound has a molecular form in a reduced state shown in FIG. 3, that is, a molecular form in which straight lines are folded and overlapped. It is stable. In this way, in the initial state, the bimolecular cumulative film 3 is in a liquid crystal state, so the surface pressure is relatively low, and the ferrocene compound of the conformational isomerization substance 4 is in the above-mentioned reduced state. Similarly, every location in the bimolecular cumulative film 3 has an averagely dense film structure. Therefore, the substance permeability of the bimolecular cumulative membrane 3 in the initial state is low, and the dye precursor 6 and the color developer 8 in the capsule and the outer phase are isolated via the capsule membrane Cf.

By the way, the bimolecular cumulative film 3 generally has a phase transition property, and is in a liquid crystal state with fluidity above the phase transition temperature Tc, whereas it is in a gel (crystalline) state below the phase transition temperature Tc. state. Therefore, the bimolecular cumulative film 3 exhibits higher barrier properties against substance permeation below the phase transition temperature Tc. In this example, the phase transition temperature Tc is set lower than the environmental temperature so that the bimolecular cumulative film 3 is in a liquid crystal state in a room temperature environment. Therefore, the bimolecular cumulative film 3 is always in a liquid crystal state and has a low barrier property against permeation of substances, so it is in an initial state (ST1) where no light is irradiated.
It also shows low material permeability. Incidentally, the phase transition temperature Tc of the bimolecular cumulative film 3 made of an amphipathic compound is 15°C to 60°C.

The first light R1 and the second light R2 are applied to the microcapsule-containing material in the initial state by the first light source 11 and the second light source 1 installed outside the transparent container 10 shown in FIG.
2 (ST2). The first light R1 is light containing a spectral component light with a wavelength of ν1, and the organic dye in the bimolecular cumulative film absorbs the component light with a wavelength of ν1 to increase electron mobility. In the case of the cyanine dye used in this example, the light corresponding to the wavelength ν1 is visible region light. The second light R2 is light containing spectral component light with a wavelength of ν2, and the conformational isomerization substance in the bimolecular cumulative film absorbs and excites the component light with a wavelength of ν2, and releases electrons. It will be cheap. When the conformationally isomerized substance is a ferrocene compound, the light corresponding to the wavelength ν2 becomes ultraviolet light.

When the first light R1 and the second light R2 as described above are irradiated simultaneously, the conformationally isomerized substance receives the second light R2 and is excited and easily releases electrons (easily oxidized). ) state, and electrons of the conformationally isomerized substance move through the organic dye whose electron mobility has increased upon receiving the first light R1. A conformationally isomerized substance that releases electrons changes its molecular three-dimensional structure. When the conformationally isomerized substance is a ferrocene compound, as shown in Figure 3, the ferrocene part loses electrons (oxidation), causing the part to undergo conformational isomerization and change from a linear molecular form to a bent molecular form. Change. The emitted electrons travel through a channel (see FIG. 2) formed by association of the organic dyes 5, and then recombine with other ferrocene compounds in an oxidized (electron emitted) state. As a result, the ferrocene compound that was in an oxidized state is reduced and returns to its original three-dimensional structure.

In FIG. 5, the first light R1 and the second light R1
By continuously irradiating 2, the conformationally isomerized substance in the bimolecular cumulative film repeatedly releases and recombines electrons. As a result, a certain proportion of the conformationally isomerized substance as a whole is oxidized and maintained in a bent molecular form. In the case of a ferrocene compound, as shown in [b] in Figure 4, when ferrocene compound 4 takes a bent molecular form (oxidation state), 2
The space occupied by the ferrocene compound 4 in the molecular cumulative film 3 increases, the nearby molecular layer is compressed, and the surface pressure of the bimolecular cumulative film 3 increases. As a result, the bimolecular cumulative film 3
The film structure becomes greatly disordered around the ferrocene compound 4. As a result, the permeability of the bimolecular cumulative membrane 3 to the substance molecules in the capsule's internal and external phases increases. This is considered to be because the substance molecules easily pass through the area where the membrane structure is disordered, that is, around the ferrocene compound 4.

Here, by controlling the intensity or time of light irradiation, the amount of molecules that actually undergo conformational isomerization among all the conformational isomerizable substance molecules contained in the bimolecular cumulative film 3 can be controlled. can be controlled. That is,
By controlling the intensity and time of light irradiation, the degree of disorder in the bimolecular cumulative film 3 can be controlled, and the substance permeability of the bimolecular cumulative film 3 can be freely controlled. As a result, as described later,
It is possible to control the mutual diffusion rate of the dye precursor 6 and the color developer 8 in the capsule and in the outer phase through the capsule membrane Cf. In addition, in the single irradiation with the first light R1 or the single irradiation with the second light R2, electrons do not move and the molecular three-dimensional structure of the conformationally isomerized substance does not change. In addition, even if light that does not contain component light with wavelengths ν1 or ν2 is irradiated, the above-mentioned conformational isomerization does not proceed, so if the wavelengths are ν1 or ν2,
Even under illumination with light that does not include the second component light, the above-described control of material permeation by light irradiation can be carried out efficiently.

In FIG. 5, when the irradiation with the first and second lights R1 and R2 is continued, the substance permeability of the capsule membrane Cf increases, and the dye precursor 6 in the inner and outer phases of the capsule and The color developer 8 begins to diffuse into each other (ST3). Then, as time passes, the amounts of the dye precursor 6 and the color developer 8 that diffuse into each other increase, and when the two come close to each other, a coloring reaction occurs and the dye 13 is produced (ST4).

Here, the amount of diffusion of the dye precursor 6 and developer 8 in the inner and outer phases varies depending on the size of the molecules that permeate the bimolecular cumulative membrane, the pressure value inside and outside the capsule, etc. It also depends on the degree of disturbance. Therefore, by changing the intensity or time of light irradiation, the rate of mutual diffusion between the dye precursor 6 and the color developer 8 and, by extension, the rate of the coloring reaction that occurs when the dye precursor 6 and the color developer 8 are mixed can be controlled. can do. In FIG. 5, the case where the first and second lights R1 and R2 are strongly irradiated is shown in the upper row, and the case where the light is weakly irradiated is shown in the lower row, and the states at the same stage are arranged vertically and compared. From this, it can be seen that in the progress stage of the coloring reaction (ST4), the amount of dye 13 produced is larger when the upper stage light is intensely irradiated.

[0054] When the coloring reaction of the microcapsule-containing material progresses and the desired coloring density is obtained, the irradiation of both the first light R1 and the second light R2 is stopped (ST5). As a result, the conformational isomerized substance is not newly excited, and the previously released electrons are donated to the conformational isomerized substance that has already been excited and released electrons (in the oxidized state). The homeoisomerized substance returns to its original molecular three-dimensional structure (reduced state). In the case of the ferrocene compound, in Figure 3, from the molecular shape of the bent state in the oxidation state,
Reduced to linear molecular form. As a result, in FIG. 4, the bimolecular cumulative film 3 returns to its original dense layered structure (reduced state [a]) in which the molecules are arranged in an orderly manner throughout. As a result, the substance permeability of the capsule membrane Cf becomes low, and mutual diffusion of the dye precursor 6 and the color developer 8 in the inner and outer phases is prevented, and the coloring reaction is stopped.

As described above, in this example, the color of the microcapsule-containing material changes from the initial colorless and transparent state to the color due to the dye 13 produced at the stage of stopping the light irradiation, and this color density can be adjusted by changing the intensity and time of the light irradiation. This allows for more precise control. In addition, if a dye substance of an arbitrary color is added in advance to the inner phase of the microcapsules MC in the initial state, the color of the microcapsules contained can be changed from the color of the arbitrary dye substance by mixing the dye 13 and the inner phase dye substance. It can be changed to a different color.

<Second Embodiment> FIG. 6 is a schematic explanatory diagram showing the concept of an apparatus for carrying out a color change control method as a second embodiment and the structure of the microcapsule-containing material used in this method. In this example, three types of microcapsules MC1,
Use MC2 and MC3. Note that a plurality of types of microcapsules MC may be used, and therefore, four or more types may be used. Therefore, these three types of microcapsules MC1
, MC2, MC3, that is, each capsule film Cf
1, Cf2, and Cf3, the wavelengths of the irradiation light that change the substance permeability are made different. In order to vary the response light wavelength of each capsule membrane, irradiation is applied to change the photoresponsivity of the organic dye molecules introduced into the two-molecule cumulative film of each capsule membrane, that is, the electron mobility of each organic dye molecule. Each wavelength of light can be made different as follows.

It is generally known that the absorption spectrum of organic dye molecules in a bimolecular cumulative film has a sharper (narrower) peak than a normal absorption spectrum. For example, the absorption spectrum of a dye-dispersed solution or a cast film shows a wide absorption spectrum because the dye molecules are aggregated in various association states, but when the dye is introduced into a bimolecular cumulative film, The absorption spectrum of
This shows a sharp peak with a narrower absorption wavelength region. This is said to be because the dye molecules are influenced by the regular orientation of the bimolecular cumulative film and associate in a certain orientation.

The absorption spectrum of an organic dye molecule with the above-mentioned sharp peak depends not only on whether the phase state of the bimolecular cumulative film is a gel state or a liquid crystal state, but also on the association state of the organic dye molecules in the bimolecular cumulative film. The absorption spectrum changes (shifts) significantly to both longer and shorter wavelengths depending on the amount of associated molecules that affect the wavelength. Therefore, if the association molecular weight of the organic dye molecules introduced into the bimolecular cumulative film is changed in three ways, the photoresponsiveness when changing the substance permeability will be sensitive, and three types of light with different wavelengths of response light will be produced. Capsule membrane Cf1, Cf
2, Cf3 can be configured. In this example, three types of ferrocene compounds having different wavelengths of light that respond to each other as conformational isomerization substances are dispersed and associated in the bimolecular cumulative film of each capsule film Cf1, Cf2, and Cf3, and cyanine as an organic dye is used. The dyes were introduced in three different amounts and associated to form capsule membranes Cf1, Cf2, Cf3.
The wavelengths of the respective response lights are made to differ from each other. Furthermore, it is also possible to adopt a configuration in which the same conformational isomerizable substance and an organic dye having different photoresponsivity are introduced into the bimolecular cumulative film of each capsule film Cf1, Cf2, and Cf3. , Cf3 can have different photoresponsiveness. Further, in this example, the substances that can be used as conformational isomerization substances and organic dyes are not limited to those described above.

Microcapsules MC1, MC2, MC3
Each internal phase contains dye precursors 1 with different coloring abilities.
The same auxiliary substance 15 as 4a, 14b, 14c is arranged. And these microcapsules MC1, MC2
, the outer phase of MC3 contains the dye precursor 14 of the inner phase of each capsule.
A color developer 16 and its auxiliary substance 17 that cause a color reaction with a, 14b, and 14c are arranged. In addition, each capsule membrane Cf
1. As the specific substances used for each of the auxiliary substances 15 and 17 in the bimolecular cumulative film, inside the capsule, and in the external phase constituting Cf2 and Cf3, the preferable substances listed in the first embodiment were selected. Can be used.

The microcapsule-containing material having the above-mentioned structure is placed in a transparent container 18, and outside of this container 18 there are three
first light sources 19a, 19b, 19c and second light source 20a
, 20b, and 20c are arranged, respectively. Each first light source 19
a, 19b, 19c are capsule membranes Cf1, Cf2, C
First lights R1a, R1b, and R1c each containing component lights of wavelengths ν1a, ν1b, and ν1c that respectively excite three types of conformationally isomerized substances contained in f3 are irradiated, respectively. Further, the second light sources 20a, 20b, and 20c emit wavelengths ν2a and ν2a, which increase the electron mobility of the three types of organic dyes, respectively.
Second lights R2a and R2 including component lights ν2b and ν2c
b and R2c are irradiated, respectively. Note that each of the lights R1 and R2 is preferably monochromatic light.

Next, a method for controlling color change of the microcapsule-containing material having the above-described structure will be explained. As shown in FIG. 7, the method of this example is similar to the first example (see FIG. 5).
Thermal stable initial stage (ST1), light irradiation start stage (S
The process consists of five stages: T2), substance diffusion initiation stage (ST3), color development reaction progress stage (ST4), and light irradiation stop stage (ST5). The state of the microcapsule-containing material at the initial stage (ST1) is the same as that in the first embodiment, and each bimolecular cumulative film of the microcapsules MC1, MC2, and MC3 is in a liquid crystal state.

By the way, each capsule membrane Cf1, Cf2,
The wavelength of light to which Cf3 responds is unique to its capsule membrane. For example, Cf1 is the only capsule membrane that responds to the first light R1a with wavelength ν1a, and this is applied to the other capsule membranes Cf2 and Cf3. It doesn't respond even if I try. Therefore, the first lights R1a, R1b, R1c and the second lights R2a, R
Even if six types of light 2b and R2c are irradiated simultaneously, the substance permeability of each capsule membrane Cf1, Cf2, and Cf3 can be controlled independently.

In FIG. 7, the above-mentioned six types of light are irradiated simultaneously, and the irradiation intensity of the first lights R1a, R1b, and R1c is varied. By controlling the light irradiation intensity in this way, it is possible to control the amount of molecules that actually undergo conformational isomerization among all conformational isomerizable substance molecules contained in the bimolecular cumulative film. can. That is, by controlling the intensity of the irradiation light, the degree of disorder in each bimolecular cumulative film is controlled, and each capsule film Cf1, Cf2, Cf
The interdiffusion rate of each dye precursor 14a, 14b, 14c and the color developer 15 in the capsule and the outer phase can be easily controlled based on the substance permeability of No. 3. In this example, the intensity of the first light R1c, which changes the electron mobility of the organic dye associated in the capsule membrane Cf3 and controls the substance permeability of the capsule membrane Cf3, is set to the highest intensity, and similarly, the intensity of the first light R1c is set to be the highest, and
The intensity of the first light R1b, which controls the material permeability of the material, is set to be the weakest. Note that the irradiation intensities of the second lights R2a, R2b, and R2c that excite the conformationally isomerized substance of this example are all set to be the same.

The first light R1a, R1b, R1c and the second light are applied to the microcapsule-containing material in the initial state (ST1).
Start irradiating the lights R2a, R2b, and R2c (ST2)
, this light irradiation operation is continued (ST3). This results in
The substance permeability of the bimolecular cumulative membrane in each microcapsule MC1 to MC3 increases, and the dye precursors 14a, 14b, 14c in the internal phase of each capsule and the color developer 15 in the external phase are transferred to two molecules of each capsule membrane Cf1, Cf2, Cf3. The molecules pass through the cumulative membrane and begin to diffuse into each other (ST3).

As the light irradiation continues, each of the dye precursors 14a, 14b, 14c in the capsule and in the outer phase changes over time.
The amount of molecules of the color developer 15 and the color developer 15 that have diffused into each other increases, and the two that come close to each other cause a color reaction, resulting in three types of dyes 21a and 21.
b, 21c are generated (ST4). At this time, each capsule membrane Cf1 of microcapsules MC1, MC2, MC3,
The amount of substance molecules that mutually diffuse through Cf2 and Cf3 varies depending on the irradiation intensity of the first lights R1a, R1b, and R1c, and the capsule membrane responds to the first light R1c with the highest irradiation intensity. The amount of substance diffusion via Cf3 is the largest, and therefore the amount of dye 21c produced thereby is the largest. Further, the amount of substance diffusion via the capsule film Cf2 in response to the first light R2 is the smallest, and therefore the amount of the dye 21b generated thereby is the smallest. Here, the color of the entire microcapsule content is determined by the three types of dyes 21a and 2 produced.
The color is a mixture of 1b and 21c. The color of the entire microcapsule-containing material can be freely controlled by adjusting the light irradiation intensity as described above.

Each dye precursor 14a, 1 in the inner and outer phases of the capsule
4b, 14c and the color developer 15 progress at their respective speeds, and when the microcapsule contents change color to the desired color and density, the first light R1a, R1b, R1c and the second light R1a, R1b, R1c are released.
The irradiation of all the lights R2a, R2b, and R2c is stopped. As a result, each microcapsule MC1, MC2, M
The conformationally isomerized substance dispersed and associated in the C3 bimolecular cumulative film is reduced and returns to its original molecular three-dimensional structure. As a result, each bimolecular cumulative film returns to its original orderly and dense film structure, and the interdiffusion of each substance in the internal and external phases of the capsule is inhibited, and the coloring reaction is stopped (ST5). In this way, it is possible to easily and accurately obtain a color-changed microcapsule-containing material with a desired color and density.

<Third Example> In the method of the first example (see FIG. 5), the bimolecular cumulative film was already in the liquid crystal state from the initial state, but in the method of this example, the bimolecular cumulative film was already in the liquid crystal state. The molecular accumulation film is kept in a crystalline state at an early stage. For this purpose, as described above, the phase transition temperature Tc of the amphiphilic compound constituting the bimolecular cumulative film may be set higher than the environmental temperature. The other configurations of the microcapsules are the same as in the first example. As a result, the bimolecular cumulative film becomes a gel state (crystalline state) from the initial stage and exhibits higher barrier properties against molecular permeation, so as shown in FIG. The material permeability of is extremely small. Therefore, the dye precursor 6 present in the inner phase of the capsule membrane Cf and the color developer 8 present in the outer phase are more reliably separated, and a small amount of substance molecules permeate each capsule membrane Cf in the initial state stage without light irradiation. Color reaction due to "leakage" can be more reliably prevented.

As in the first embodiment, the first light R1 is applied to the microcapsule MC having a bimolecular cumulative film in a crystalline state.
and irradiates the second light R2 (ST2). Due to this light irradiation, the conformationally isomerized substance dispersed and associated in the bimolecular cumulative film is oxidized (releases electrons) and attempts to change the molecular three-dimensional structure, but the bimolecular cumulative film is in a crystalline state. It is regulated by the membrane, and the membrane structure is not sufficiently disturbed. Therefore, the substance permeability of the bimolecular cumulative film hardly increases, and the dye precursor 6 and the color developer 8 in the internal and external phases do not pass through the capsule film Cf. This state does not substantially change even if the respective intensities of the first light R1 and the second light R2 are increased.

Next, the microcapsule-containing material is heated to a temperature higher than the phase transition temperature Tc of the bimolecular cumulative film to cause the bimolecular cumulative film to undergo a phase transition to a liquid crystal state. As a result, the regulating force of the bimolecular cumulative film disappears, the molecular three-dimensional structure of the conformationally isomerized substance changes into a bent shape (see Figure 3), and the membrane structure of the bimolecular cumulative film is disturbed (ST3). . As a result, the substance permeability of the capsule membrane Cf increases, and the dye precursor 6 present in the capsule inner phase and the color developer 8 present in the outer phase each pass through the capsule membrane Cf and begin to diffuse into each other (ST4). After that, if the irradiation of the first and second lights R1 and R2 is continued, and the heating of the microcapsule-containing material is continued to maintain the system temperature above the phase transition temperature Tc, mutual diffusion of substances will proceed. , a coloring reaction occurs and dye 13 is produced (ST5
).

Eventually, when the mutual diffusion of the substances contained in the microcapsules has progressed to a desired degree, the irradiation of the first and second lights R1 and R2 is stopped. As a result, the conformationally isomerized substance in the bimolecular cumulative film is reduced and returns to a linear molecular three-dimensional structure (see FIG. 3), and the bimolecular cumulative film returns to its original layered structure. As a result, the substance permeability of the capsule membrane Cf changes as shown in Figure 5, since the bimolecular cumulative membrane remains in a liquid crystal state.
The coloring reaction is reduced to the initial stage (ST1) of the first embodiment shown in FIG. 1, and mutual diffusion of the dye precursor 6 and the color developer 8 in the capsule and the outer phase is prevented, and the coloring reaction is stopped (ST6). In addition to stopping the light irradiation, the coloring reaction can be stopped by lowering the environmental temperature below the layer transition temperature of the bimolecular cumulative film. In this way, according to the method of this example, the color change of the microcapsule-containing material can be controlled not only by light irradiation but also by adjusting the environmental temperature, so the color change of the microcapsule-containing material can be controlled more precisely. Is possible. In the second embodiment described above, which contains multiple types of microcapsules, as shown in FIG. can be reliably prevented, and a more precise substance diffusion control effect can be easily obtained.

<Fourth Example> FIG. 10 is a schematic explanatory diagram showing a method for controlling color change of a material containing microcapsules as a fourth example. The method of this example is based on the configuration of the third example, and further includes a polymer resin whose viscosity rapidly decreases as the environmental temperature rises as a viscosity adjusting substance among the auxiliary substances placed inside the capsule and in the outer phase. It uses wax. Here, a case will be explained taking as an example a case in which a viscosity adjusting substance is arranged in the internal phase of the capsule. Then, the temperature at which the viscosity of the viscosity adjusting substance rapidly decreases is set near the phase transition temperature Tc of the bimolecular cumulative film.

[0072] As a result, under normal environmental temperature (ST1
In ST2), since the bimolecular cumulative film of the capsule film Cf is in a crystalline state and the viscosity of the capsule internal phase is high, the dye precursor 6 contained therein is extremely difficult to diffuse into the external phase.
Further, the color developer 8 contained in the outer phase is also in a state where it is extremely difficult to diffuse into the highly viscous inner phase. Therefore, the dye precursor 6 and the color developer 8 in the capsule and in the outer phase are separated more reliably than in the third embodiment. Therefore, it is possible to more completely prevent a coloring reaction caused by "leakage" in which a small amount of substance molecules pass through the capsule film Cf in the initial stage (ST1) when no light is irradiated.

Irradiation of the first and second lights R1 and R2 (ST2
), the microcapsule-containing material is heated above the phase transition temperature Tc of the bimolecular cumulative film (ST
3). As a result, the bimolecular cumulative film transitions to a liquid crystal state, and the viscosity of the above-mentioned viscosity adjusting substance contained in the capsule internal phase rapidly decreases. As a result, the dye precursor 6 in the inner phase and the color developer 8 in the outer phase begin to diffuse into each other as in the first embodiment (ST4). Then, mutual diffusion between the dye precursor 6 and the color developer 8 in the inner and outer phases progresses, and a coloring reaction occurs.
When the desired color density is obtained (ST5), the irradiation of the first and second lights R1 and R2 is stopped, and the temperature is returned to the initial state (S
The temperature is lowered to the same temperature as T1) (ST6). This results in
The state of the microcapsule contents returns to the initial state (ST1). That is, the internal phase of the capsule returns to its original high viscosity, the bimolecular cumulative film returns to a crystalline state, and the conformationally isomerized substance is reduced to return to the layered structure. This results in
The substance permeability of the capsule membrane Cf is reduced to the same level as the initial state (ST1), and the coloring reaction is reliably stopped. Note that the color reaction can be stopped by simply lowering the temperature or stopping light irradiation.

As described above, according to this example, the coloring reaction based on the mutual diffusion of substances can be easily controlled not only by light but also by temperature, as in the third example, and the coloring reaction based on the mutual diffusion of substances can be controlled in the initial stage. The advantage is that color development due to "leak" transmission can be more completely prevented. Incidentally, even if a similar viscosity adjusting substance is disposed as the outer phase substance of the capsule, the same effect can be obtained. Further, as in the second embodiment, even when a plurality of types of microcapsules are contained, the same method as in this embodiment can be applied, as shown in FIG. 11.

Although the present invention has been described above in detail based on four embodiments, the present invention is not limited to these specific embodiments, and various modifications can be made within the technical scope of the invention. Of course, it is possible. For example, in the above embodiments, the dye precursor is placed in the capsule inner phase, and the color developer is placed in the capsule outer phase, but conversely, the color developer is placed in the capsule inner phase, and the dye precursor is placed in the capsule outer phase. You can. In addition, in the second embodiment, as shown in FIG. 7, the intensity of the second lights R2a, R2b, and R2c is kept constant, and the
Although only the intensities of 1a, R1b, and R1c are changed to individually control the substance diffusion rate in each of the microcapsules MC1, MC2, and MC3, the present invention is not limited to this. Conversely, by keeping the intensity of the first lights R1a, R1b, R1c constant and varying the respective intensities of the second lights R2a, R2b, R2c, the material diffusion of each microcapsule MC1, MC2, MC3 can be made unique. can be controlled. Furthermore, in the second embodiment,
Although dye precursors having different color-forming abilities are placed in a plurality of types of microcapsules having different photoresponsiveness, dye precursors having the same color-forming ability may be placed in different types of microcapsules. That is, in FIG. 6, the same dye precursor 14a may be disposed in each inner phase of microcapsules MC1 and microcapsules MC2.

[0076]

[Effects of the Invention] As explained above in detail, according to the present invention, a conformational isomerizable substance and an organic dye are contained as photoresponsive substances in the micropores of a capsule membrane formed of a porous material. A photoresponsive capsule membrane is constructed by embedding a bimolecular cumulative membrane to change substance permeability in response to light irradiation, and a dye precursor is placed in either the inner or outer phase of this capsule membrane and the dye precursor is placed in the other. By arranging a coloring agent to configure a microcapsule-containing material, the microcapsule-containing material is treated with light of a specific wavelength that can redox and reduce conformational isomerization substances, and the electron mobility of the organic dye is changed. The degree of progress of the coloring reaction based on the mutual diffusion of the dye precursor and the color developer can be easily and precisely controlled simply by irradiating light of the same wavelength. In this case, since two types of photoresponsive substances are contained in the bimolecular cumulative film, the selection range of bimolecular cumulative film materials is widened, and microcapsules with desired photoresponsiveness can be easily manufactured. By adjusting the intensity of the irradiated light, the rate of permeation and diffusion of the dye precursor and color developer through the capsule membrane, as well as the degree of progress of the coloring reaction, can be more precisely controlled, resulting in the desired color and density. It becomes possible to easily obtain a microcapsule-containing material that changes color accurately. Further, since the substance permeability of the bimolecular cumulative film does not change with light having a wavelength other than the above-mentioned specific wavelength, the coloring reaction can be precisely controlled even under normal light illumination, which is extremely convenient in practice. Furthermore, since the light irradiation requires only a very short period of time, such as pulsed light irradiation, high-speed light control of the coloring reaction becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing the concept of the structure of a color-changing microcapsule-containing material and a method of controlling color change thereof as an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the detailed structure of a capsule membrane in the microcapsule-containing material.

FIG. 3 is an explanatory diagram showing an isomerization reaction of a conformationally isomerized substance in the capsule membrane.

FIG. 4 is an explanatory diagram showing the transition of a bimolecular cumulative film containing the isomerized substance.

FIG. 5 is a schematic explanatory diagram showing an example of a method for controlling color change of the color-changing microcapsule-containing material.

FIG. 6 is a schematic explanatory diagram showing the concept of a color-changing microcapsule-containing material and a color-changing control method using the same as another embodiment of the present invention.

7 is a schematic explanatory diagram showing an example of a color change control method using the color change microcapsule-containing material shown in FIG. 6. FIG.

FIG. 8 is a schematic explanatory diagram showing a color change control method as still another embodiment of the present invention.

9 is a schematic explanatory diagram showing a modification of the embodiment shown in FIG. 8. FIG.

FIG. 10 is a schematic explanatory diagram showing a color change control method as still another embodiment of the present invention.

FIG. 11 is a schematic explanatory diagram showing a modification of the embodiment of FIG. 10;

FIG. 12 is a schematic cross-sectional view showing a conventional microcapsule-containing material.

[Explanation of symbols]

1 Wall material 2 Pore 3 Bimolecule cumulative film 4 Conformationally isomerized substance 5 Organic dye 6, 14a, 14b, 14c Dye precursor 7, 9, 1
5,17 Auxiliary substances8,16 Color developer10,18 Container

Claims (12)

[Claims] 1. A microcapsule-containing material containing microcapsules made of a capsule membrane that changes substance permeability upon irradiation with light, wherein the capsule membrane has a conformation that changes its three-dimensional structure through a redox reaction. It has a bimolecular membrane containing an isomerizable substance and an organic dye with spectral sensitizing properties, a dye precursor is disposed in one of the inner phase and an outer phase of the capsule membrane, and a color developer is disposed in the other, When the bimolecular membrane is irradiated with light of a specific wavelength, the material permeability increases,
A color-changing microcapsule-containing material having a photoresponsive film, characterized in that the dye precursor and the color developer develop color by mutually diffusing and mixing. 2. Containing a plurality of types of microcapsules in which the specific wavelength to which the bilayer membrane responds differs from each other,
2. The color-changing microcapsule-containing material according to claim 1, wherein dye precursors producing different dyes are arranged in each inner phase of the plurality of types of microcapsules, and a color developer is arranged in the outer phase. 3. Claim 1, wherein a material having a phase transition temperature that becomes a liquid crystal state at room temperature is selected as the material of the bilayer film.
or the color-changing microcapsule-containing material according to 2. 4. A material having a phase transition temperature at which it becomes a crystalline state at room temperature is selected as the material for the bilayer film, and the bilayer film is irradiated with light of the specific wavelength and heated, thereby increasing the material permeability. The color-changing microcapsule-containing material according to claim 1 or 2, which increases . 5. The color according to claim 4, wherein a substance whose temperature at which the viscosity rapidly decreases with increasing temperature is sufficiently close to the phase transition temperature of each of the bilayer membranes is added to the inner phase or the outer phase of each of the microcapsules. Variable microcapsule inclusions. 6. A pigment substance of an arbitrary color is arranged in advance in the inner phase of the microcapsule, and the color changes to a mixture of the pigment substance and a pigment produced by a coloring reaction caused by the light irradiation. Color-changing microcapsule inclusions as described. 7. A microcapsule comprising a capsule membrane having a bimolecular membrane that changes substance permeability upon receiving light of a specific wavelength, wherein either an inner phase or an outer phase of the capsule membrane contains a dye precursor. A developer is placed on the other side, and the above 2.
The molecular film contains a conformational isomerizable substance that changes its 3D structure through redox reaction and an organic dye with spectral sensitization properties, and when irradiated with light at a specific wavelength, changes the 3D structure of the molecule and increases substance permeability. A method for controlling the color change of a color-changing microcapsule-containing substance having photoresponsiveness, the method comprising increasing substance permeability by irradiating the capsule membrane, which is in a state of low substance permeability, with light of the specific wavelength. In particular, the photoresponsive film is characterized in that the amount of light irradiated with the specific wavelength is adjusted to control the color change of the entire microcapsule-containing material due to mutual diffusion between the dye precursor and the color developer. A method for controlling color change of a color change microcapsule containing material. 8. Containing a plurality of types of microcapsules in which the specific wavelength to which the bilayer membrane responds differs from each other,
8. The color change control method according to claim 7, wherein dye precursors that produce different dyes are arranged in each inner phase of each of the plurality of types of microcapsules, and a color developer is arranged in the outer phase. 9. The color change control method according to claim 7, wherein a material having a phase transition temperature at which the bilayer film becomes a liquid crystal at room temperature is selected as the material for the bilayer film. 10. A material having a phase transition temperature at which it becomes a crystalline state at room temperature is selected as the material for the bilayer membrane, and
9. The color change control method according to claim 7, wherein substance permeability is increased by irradiating the molecular film with light of the specific wavelength and heating it. 11. The color according to claim 10, wherein a substance whose temperature at which the viscosity rapidly decreases with increasing temperature is sufficiently close to the phase transition temperature of each of the bilayer membranes is added to the inner phase or the outer phase of each of the microcapsules. Change control method. 12. A coloring substance of an arbitrary color is added to the inner phase of the microcapsule in advance, and the color change is controlled to a color obtained by mixing the coloring substance and a dye produced by a coloring reaction caused by the light irradiation. 12. The color change control method according to 11.