JPH11344688A - Stimuli-responsive polymer composition and optical element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-holding stimuli-responsive polymer composition which is free from liquid leakage and bubbles and can be used in a wide range of applications, and an optical element using the same. SOLUTION: A self-holding stimuli-responsive polymer composition having a region containing a stimuli-responsive polymer material and a liquid, whose solubility in a liquid is changed by application of a stimulus, and an isolation member surrounding the region. is there. The stimulus-responsive polymer composition is
The microcapsules are preferably composed of the above-mentioned region and a polymer film surrounding the region, and the separating member is preferably a matrix. The stimulus-responsive polymer composition can be used as various optical elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stimulus-responsive polymer composition whose solubility in a liquid is changed by the application of a stimulus, and an optical element using the same. More specifically, the present invention relates to a light-adjusting element, a sensor or a light-emitting material that controls light transmittance, light scattering or light absorption when a stimulus is applied, and controls color transmission material for image display or recording. The present invention relates to a stimuli-responsive polymer composition that can be used for filters and the like, and an optical element using the same.

[0002]

2. Description of the Related Art At present, a polymer material whose solubility in a liquid is reversibly changed by application of heat, light, electric current or electric field (hereinafter, referred to as a polymer material). A solution composition that can reversibly change light transmittance using “stimulus-responsive polymer material”) is known. Among these stimuli-responsive polymer materials, examples of the heat-sensitive material that changes with temperature include poly (meth) acrylamide, polyN-alkyl-substituted (meth) acrylamide, and polyvinyl methyl having a lower critical solution temperature (LCST). Aqueous solutions of high molecular compounds such as ether and polymethacrylic acid (Japanese Patent Publication Nos. 61-7948, JP-A-3-237426, JP-A-8-828)
No. 09) is known.

As an application example using such a material, N
A technique (Japanese Patent Publication No. 61-7948) relating to a heat-sensitive light-shielding material in which a composition of isopropyl (meth) acrylamide and water is laminated on a transparent plate. This technology utilizes the property that an aqueous solution of N-isopropyl (meth) acrylamide is transparent at low temperatures, but becomes opaque due to insolubilization and precipitation of N-isopropyl (meth) acrylamide at high temperatures. It has been proposed to use it as a light-blocking member such as a blind that controls transmitted light autonomously depending on the temperature of the light. In addition, a technique relating to a dimming element or a display element in which a similar composition or the like is sandwiched between substrates provided with heat generating means and electric means (Japanese Patent Application Laid-Open Nos. 2-17099 and 5-1811)
No. 67, JP-A-6-43500) are also disclosed.

[0004]

However, conventional stimuli-responsive polymer materials and their compositions have no self-holding property as they are in a solution state. For example, when applied to an optical element, It is necessary to sandwich it between two substrates and enclose it, and the like, and its use range has been limited. In addition, such an optical element has problems such as deterioration of characteristics due to liquid leakage or generation of bubbles.

[0005] Further, when the stimulus-responsive polymer material changes its response by being stimulated, particularly when it is insoluble, coarse aggregates are formed to decrease the response speed, There was a fear that the repetition characteristics deteriorated. Furthermore, since the conventional one uses the principle of changing the light scattering property, it cannot express various colors, and its field of use has been limited.

[0006] The present invention has been made to solve the above-mentioned problems in the prior art. That is, an object of the present invention is to provide a self-holding stimuli-responsive polymer composition which is free from liquid leakage and generation of bubbles and can be used in a wide range of applications, and an optical element using the same. Another object of the present invention is to isolate and hold a stimulus-responsive polymer solution in a minute area, thereby suppressing the formation of coarse aggregates due to a change in stimulus response and improving the response speed and stability. An object of the present invention is to provide a self-holding stimulus-responsive polymer composition and an optical element using the same. Still another object of the present invention is to provide a self-holding stimulus-responsive polymer composition capable of easily expressing various colors and an optical element using the same.

[0007]

The self-holding stimulus-responsive polymer composition of the present invention comprises a region containing a stimulus-responsive polymer material and a liquid, the solubility of which changes with the application of a stimulus. It has a separating member surrounding the area. The region containing the stimulus-responsive polymer material and the liquid preferably contains a coloring material. Further, the separating member is preferably a matrix, and more preferably a matrix made of a polymer compound. In addition, the stimulus-responsive polymer composition of the present invention has a microstructure comprising a region containing a stimulus-responsive polymer material whose solubility in a liquid is changed by application of a stimulus and a liquid, and a polymer film surrounding the region. It is a capsule.

The optical element of the present invention is a self-holding device having a region containing a stimulus-responsive polymer material whose solubility in a liquid is reversibly changed by the application of a stimulus and a liquid, and an isolation member surrounding the region. Characterized by being formed using a stimuli-responsive polymer composition of a sexual nature. Further, the optical element is preferably provided on the base material or between the base materials, and further, it is preferable that means for applying heat, an electric field, a current or light be provided on the base material. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The stimulus-responsive polymer composition of the present invention has a self-holding property, and when a stimulus is applied, the solubility in a liquid changes, and the stimulus-responsive polymer is dissolved or insoluble in the liquid. It has a region containing a material and a liquid, and a separating member surrounding the region, and a configuration example of the stimulus-responsive polymer composition will be described with reference to the drawings using an embodiment.

FIG. 1 is a schematic diagram showing the form of the stimulus-responsive polymer composition of the present invention. FIG. 1A shows a mixture of a stimuli-responsive polymer material and a liquid (hereinafter, referred to as a “stimulus-responsive liquid”) separated and separated in a phase-separated state inside a matrix serving as an isolation member. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows one form of a composition. FIG. 1 (b) shows the inside of a capsule membrane made of a polymer compound as a separating member.
It is a schematic block diagram which shows another form of the composition which enclosed the stimuli-responsive liquid. FIG. 1C is a schematic configuration diagram showing another embodiment of a composition in which a stimulus-responsive liquid containing a coloring material is enclosed in a capsule film made of a polymer compound serving as an isolation member. . Further, FIG. 1 (d) shows another embodiment of a composition in which a plurality of capsules in which a stimuli-responsive liquid is sealed inside a capsule membrane made of a polymer compound as a separating member are dispersed in a matrix. It is a schematic block diagram.

Next, the constituent materials of the stimulus-responsive polymer composition of the present invention and the method for producing the same will be described. As used in the present invention, as a stimulus-responsive polymer material having a property that solubility in a liquid is changed by application of a stimulus,
The solubility of the solution changes depending on the pH value, ionic strength, adsorption and desorption of chemical substances, addition of solvent, application of heat, light, electric current and electric field, etc., easily forming a state of dissolving and insolubilizing in the liquid used. What can be done is preferred. Generally, these changes in solubility can be unidirectional or reversible.

In the present invention, the change in solubility due to the application of a stimulus means a one-phase state in which a polymer compound is dissolved in a liquid, and the two components of the polymer compound and the liquid are practically almost uniform. It can be defined as a change between an inhomogeneous two-phase state in which the polymer compound is insoluble in the liquid. These changes in state can be distinguished by an almost optically transparent state and an opaque light scattering state. In the heterogeneous state in which the polymer compound is insoluble in the liquid, the polymer compound may be in a solid state in which the liquid is almost completely excluded from the polymer compound, or may be in a semi-solid state in which the polymer compound partially contains the liquid.

The stimulus-responsive polymer material having the above properties used in the present invention will be described. As a substance whose solubility in a liquid is changed by application of heat, usually, 20
A polymer compound that undergoes a phase transition when heated from 100 ° C. to 100 ° C. to be insolubilized or solubilized in a liquid. Specifically, poly (meth) acrylamide, poly-N-isopropyl (meth) acrylamide, and other polyN- Alkyl substitution (meth)
Acrylamide, N-vinylisobutylamide, polyvinyl alkyl ether such as polyvinyl methyl ether,
Poly (oxyethyleneoxyvinyl ether), poly (meth) acrylic acid or its metal salt, poly-2-hydroxyethyl (meth) acrylate, poly-N- (meth) acrylpiperidine, poly (2-ethyloxazoline), polyvinyl alcohol Or its partially saponified material,
Polyethylene oxide, copolymers of polyethylene oxide and polypropylene oxide, poly (ethylene glycol monomethacrylate), poly (ethylene glycol monoacrylate), substituted cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and the like, or Copolymers and polymer blends containing a high molecular compound as a main component are exemplified.

[0014] In addition, as a substance whose solubility in a liquid is changed by a change in pH value or a change in ionic strength due to the adsorption and desorption of a chemical substance, a change in a solvent composition, an electrode reaction based on the application of an electric current or an electric field, a poly ( (Meth) acrylic acid or a metal salt thereof, polyvinyl sulfonic acid, polyvinyl benzene sulfonic acid, poly (meth) acrylamidoalkyl sulfonic acid, polymaleic acid or a metal salt thereof, or a monomer component constituting these high molecular compounds as a main component The copolymer obtained as a main component is a polyvinyl alcohol-polyacrylic acid complex or a metal salt thereof, poly (ethylene glycol monomethacrylate), a metal salt of carboxymethyl cellulose, a metal salt of carboxyethyl cellulose, or a polymer compound thereof. Copolymers and polymer blends as components That.

In the above-mentioned chemical substance adsorption / desorption system, various surfactants, ionic low molecular weight compounds such as amines, quaternary amine salt derivatives, acids and acid chloride derivatives are added to the above-mentioned high molecular weight compounds. The solubility of the high molecular compound can be changed by controlling the absorption and desorption of the high molecular compound by adding an electric field or an electric current to the high molecular compound. Further, when the solubility is changed depending on the pH value, for example, in the case of poly (meth) acrylate, etc., it is insoluble at a pH of 2 or less,
Then dissolve. As a preferable range of this pH change,
The pH is in the range of 1-12. Such a change can be made by adding an acid or an alkali or by an electrode reaction.

As a compound whose solubility is changed by the application of light, there is a polymer compound having a group such as a photochromic group whose structure is changed by a photoreaction. Poly (meth) acrylamides having groups such as phenylmethane derivatives, spiropyran derivatives and spirooxazine derivatives, poly-N-
Various types such as poly N-alkyl-substituted (meth) acrylamides such as isopropyl (meth) acrylamide, polyvinyl alkyl ethers such as N-vinyl isobutylamide and polyvinyl methyl ether, and poly (oxyethylene oxyvinyl ether) are exemplified. . The change in solubility due to this light is caused by, for example, the above-mentioned triphenylmethane derivative undergoing a cleavage reaction when irradiated with ultraviolet light having a wavelength of about 350 nm, so that the solubility in water is improved. Irradiation causes the opposite reaction to occur, and reduces the solubility in water. The wavelength of irradiation light when applying light is preferably in the range of 250 to 830 nm.

As a compound whose solubility is changed by an oxidation / reduction reaction by electricity, there is a CT complex (charge transfer complex) of a cationic polymer compound and an electron accepting compound,
Specifically, amino-substituted (meth) acrylamides such as dimethylaminopropylacrylamide, (meth) acrylic acids such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, and dimethylaminopropyl acrylate
Amino-substituted alkyl acrylate, polystyrene derivative, polyvinyl pyridine derivative, polyvinyl carbazole derivative, polydimethylaminostyrene, etc., and benzoquinone, 7,7,8,8-tetracyanoquinodimethane (TCNQ), tetracyanoethylene, chloranil, It is used in combination with an electron accepting compound such as trinitrobenzene, maleic anhydride or iodine. Regarding the change in solubility due to the adsorption / desorption of the chemical substance due to the oxidation / reduction reaction due to the application of the electric current or the application of the electric field, it is preferable to apply a voltage of about 1 to 200 V to the electrode.

The liquid used in the stimuli-responsive polymer composition of the present invention includes water, an aqueous electrolyte solution, alcohols such as methanol, ethanol, propanol and butanol, ketones, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and the like. Examples include acetonitrile, propylene carbonate, other aromatic organic solvents, aliphatic organic solvents, and mixtures thereof. Also,
The liquid contains surfactants and response enhancers that can be used to control the stimulus response characteristics, viologen derivatives to promote the pH change of the solution, acids, alkalis, salts, dispersion stabilizers, antioxidants, or ultraviolet absorption A stabilizer such as an agent may be added.

In the present invention, a preferable combination of the stimulus-responsive polymer material and the liquid is poly-N-isopropyl (meth) acrylamide or a copolymer containing N-isopropyl (meth) acrylamide as a main component, water or A solution composed mainly of water, a solution composed of polyvinyl methyl ether or a copolymer composed mainly of vinyl methyl ether and water or a solution composed mainly of water, poly (meth) acrylate Or a copolymer comprising a (meth) acrylate-based copolymer and water, an aqueous electrolyte solution or a water-based solution, dimethylaminopropyl (meth) acrylamide or a copolymer containing the same as a main component Each complex of the coalesce, ketone, dimethylformamide, dimethylacetamide, dimethylsulfoxide,
Examples thereof include those composed of acetonitrile, propylene carbonate, and other aromatic organic solvents. The compounding ratio of the stimulus-responsive polymer material to the liquid in the stimulus-responsive liquid is preferably in the range of 1/2000 to 1/1 (stimulus-responsive polymer material / liquid).

In the present invention, in order to express various colors, it is preferable to add a coloring material such as a pigment or a dye to the stimulus-responsive liquid to obtain a colored composition. The added coloring material preferably has the stimulus-responsive polymer material uniformly dispersed or dissolved in the composition in a dissolved state. On the other hand, when the stimulus-responsive polymer material is in an insoluble state, the coloring material is preferably incorporated into the polymer material. In other words, when the stimuli-responsive polymer material in the stimuli-responsive liquid becomes insoluble, the polymer material precipitates or precipitates in the liquid. At that time, most of the coloring materials in the composition are It is desirable that the coloring material is incorporated in the polymer material and the concentration of the coloring material in the liquid is extremely low. Further, it is desirable that the colorant concentration in the insolubilized polymer material solution is equal to or higher than the saturation absorption concentration. When such a state is obtained, the optical density (color density) changes due to the change in dissolution-insolubility of the stimulus-responsive polymer compound.
Can be greatly changed.

The colorant concentration which is higher than the saturated absorption concentration is generally 5% by weight in the insoluble polymer material.
It is preferable that the above concentration be obtained. In particular, the concentration range of the coloring material present in the insoluble polymer material is preferably in the range of 5 to 95% by weight. In order to realize such a color material concentration, the amount of the color material added to the stimulus-responsive liquid is 0.01
The range of -20% by weight is preferred.

Examples of usable coloring materials include various pigments and dyes. Inorganic pigments, organic pigments, basic dyes, acid dyes, disperse dyes, and reactive dyes are used. Examples include metal oxides such as titanium oxide, bronze powder, carbon black, anthraquinone-based, azo-based, phthalocyanine-based, quinacridone-based, perylene-based, and indigo-based pigments and dyes. Among them, pigments are preferred because the addition thereof has a relatively small effect on the stimulus-responsive function of the stimuli-responsive polymer material. In addition, as a preferable particle size when using a pigment, an average particle size of primary particles of 0.001 to 1 μm is preferable.

It is preferable to use a coloring material having a large interaction with the stimuli-responsive polymer material or a coloring material having a property of easily forming an aggregate when the concentration of the coloring material in the composition is high. Such colorants include acid groups, hydroxyl groups,
It is preferable to use one having a polar group such as an amino group, a thiol group, a halogen atom, a nitro group, or a carbonyl group, and having a property of easily forming an aggregate when the colorant concentration is high.

Further, it is preferable that the coloring material is chemically bonded as one component of the stimuli-responsive polymer material. The chemical bond is preferably an ionic bond or a covalent bond, and particularly preferably a covalent bond. As this means, a method of copolymerizing a dye or pigment compound having a polymerizable group with a precursor of a stimuli-responsive polymer material is used. And a method of reacting a dye or pigment compound having an addition reactive group represented by a reactive dye or the like with a stimulus-responsive polymer material.

As the separating member used in the stimulus-responsive polymer composition of the present invention, various polymer materials or inorganic materials such as glass can be used. Further, among them, it is preferable to use a material having high light transmittance, and among them, a polymer material is more preferably used because it is easily processed. The isolation member may be made of a plurality of types of materials, and may be formed of a plurality of layers.

As the form of the separating member, various modes can be adopted as shown in FIG. FIG. 1 (a) shows an embodiment in which the separating member forms a continuous layer,
As shown in (b) and (c), a microcapsule in which the isolation member is an encapsulation film, and further, as shown in FIG. Multiple configurations with layers are possible.

In the embodiments shown in FIGS. 1A and 1D, the matrix material used as the separating member is a polyester resin, a polycarbonate resin, a polyvinyl chloride resin, polyvinylidene fluoride or a heterogeneous copolymer thereof, or polytetrafluoroethylene. Fluoroethylene, polystyrene and its heterogeneous copolymer, polymethyl methacrylate and its heterogeneous copolymer, polyamide-based resin, silicone-based resin, acrylic and vinyl-based curable resin that is cross-linked by heat, ultraviolet light or electron beam, Silane-based sol-gel compositions and the like can be mentioned.
Also, the matrix material may be cross-linked.

In the embodiment shown in FIGS. 1 (a) and 1 (d), a stimulus-responsive liquid or a microcapsule containing a stimulus-responsive liquid described below is dispersed in a matrix material and formed by a method of solidifying. Can be. For example, FIG.
In the embodiment (a), the stimulus-responsive liquid is dispersed and mixed in a liquid of a matrix material that does not dissolve the stimulus-responsive liquid, and the stimulus-responsive liquid is dispersed in a phase-separated state and then dried, or ultraviolet irradiation or heating is performed. Can be manufactured by solidifying the matrix material. FIG. 1 (d)
1 can be formed in the same manner as that of FIG. 1 (a). However, since the stimuli-responsive liquid is encapsulated inside the microcapsules, the selection range of the matrix material and the degree of freedom of the process are possible. Expands more. For example, a method of dispersing in a heat-melted matrix material, followed by cooling and solidifying is also possible.

In the embodiments shown in FIGS. 1A and 1D, the composition ratio between the matrix material as the separating member and the stimulus-responsive liquid or the capsule containing the same is 1/1 by weight.
The range of 50 to 50/1 [matrix material / (stimulus-responsive polymer + liquid) or matrix material / (capsule containing stimulus-responsive polymer and liquid)] is preferable. If the ratio exceeds this range, desired optical characteristics and physical strength of the material may not be obtained. Further, the size of the region (drop) formed by the stimulus-responsive liquid in the mode of FIG.
The same range as the size of the microcapsule described later is preferable.

On the other hand, the embodiment in which the separating member is a capsule membrane [FIGS. 1B and 1C] can be obtained by a conventionally known encapsulation method or a microcapsule manufacturing method. Examples of the method for producing microcapsules include a coacervation method using insolubilization of a polymer material, an interfacial polymerization microcapsulation method in which polymerization is performed at the interface of dispersed particles to form a capsule film, an in situ microencapsulation polymerization method, and a liquid. A microencapsulation method in which a cured coating is formed in the inside, a spray-drying microencapsulation method in which droplets are sprayed in a gas and a capsule film is formed on the surface, and the like. Details of these techniques are described in Sankyo Shuppan, published by Tamotsu Kondo, "New Edition Microcapsules, Their Manufacturing Methods, Properties, and Applications".

The main materials that can be used for the polymer film (capsule film) of the microcapsules include polyvinyl acetate, cellulose acetate butyrate, styrene-maleic acid copolymer, benzyl cellulose, ethyl cellulose, polyethylene, polystyrene, rubber, Nitrocellulose,
Polymethyl methacrylate, polyester, polyamide, polyurethane, polyurea, polyether, polysaccharides such as alginic acid, pectin, carrageenan, and xanthan, proteins such as polyvinyl alcohol, gelatin, and albumin, and epoxy resins are used.

The microcapsule composition of the present invention can be specifically manufactured as follows.
(A) a method in which a stimuli-responsive liquid prepared in advance is added to a solution containing a polymer compound for a capsule, and then a coacervation treatment is performed to form a capsule; Liquid mixture with molecular precursor,
A method in which microcapsules are formed by interfacial polymerization by adding to a solution containing a substance that reacts with the precursor, (c) a mixed liquid of a stimulus-responsive liquid and a polymer compound for capsules,
There is a method of adding a solution containing a substance that reacts with the polymer compound to insolubilize or cross-link the polymer material to form a capsule.

In the above encapsulation process,
The desired particle size and shape can be obtained by using a stirring method with a stirrer, a method of discharging a capsule composition from a nozzle having a fine diameter to form a capsule, or a method of spraying the capsule composition to form a capsule. Can be formed.

Further, it is preferable that the polymer film constituting the microcapsule has a light transmitting property. Furthermore, in addition to the function of retaining the stimuli-responsive liquid inside the microcapsule, the polymer membrane of the capsule may have a function of transmitting ions and chemical substances. It may have a transmission function.

The thickness of the polymer film constituting the microcapsules is preferably in the range of 1 nm to 20 μm, more preferably in the range of 1 nm to 10 μm. If the thickness of the polymer film is smaller than 1 nm, the physical strength of the microcapsules decreases, while if it is larger than 20 μm, the concentration of the stimuli-responsive liquid in the composition decreases, and the optical properties may decrease. There is. The size of the microcapsules is 0.
The range is preferably from 02 μm to 10 mm, and from 0.02 μm to
A range of 2 mm is more preferred. If the size of the microcapsules is smaller than 0.02 μm, the handleability becomes poor,
On the other hand, if it is larger than 10 mm, responsiveness and stability may decrease.

The mixing ratio between the polymer material constituting the microcapsules and the stimuli-responsive liquid is 1/100 by weight.
The range of 0 to 5/1 [polymer material / (stimulus-responsive liquid)] is preferable. If the compounding ratio is less than 1/1000, the physical strength of the microcapsules decreases, while
If the ratio is more than / 1, the density of the stimuli-responsive liquid in the composition may decrease, and the optical properties may decrease. In addition, various additives such as inorganic particles and fillers may be added to the polymer film constituting the capsule. The above-described stimulus-responsive polymer composition of the present invention can be widely used as an optical element such as a light control element and a display element.

Next, an optical element using the stimulus-responsive polymer composition of the present invention will be described. Since the composition in the form shown in FIGS. 1A and 1D is solid, it has self-holding properties and can be processed into a film or plate shape and used as an optical element. Furthermore, in order to improve strength, durability and function, the polymer composition is formed in a layer on another substrate, or the polymer composition is layered between two substrates. It is also preferable that the optical element is sandwiched.

FIG. 2 shows a structural example of the optical element of the present invention.
FIG. 2A shows a configuration example in which a stimulus-responsive polymer composition 2 is formed in a layer on a substrate 1. FIG. 2B shows a configuration example in which a stimulus-responsive polymer composition 2 is formed in a layer between two substrates 1 via a spacer 3. FIG.
In the configuration of (b), it is possible to fill the space between the two substrates with various liquids and gases in addition to the stimulus-responsive polymer composition. FIG. 2C shows an example of a configuration in which a stimulus applying unit 4 is provided on a substrate in addition to the configuration of FIG. 2B.

In the above configuration example of the optical element, the layer thickness of the stimulus-responsive composition is in the range of 1 to 500 μm,
A range of 200 μm is preferred. If it is smaller than 1 μm,
The optical characteristics may be reduced, and if it is 500 μm or more, the response characteristics and the like may be reduced. Further, as the substrate 1, a film or a plate-like substrate of polyester, polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, nylon, polycarbonate, polyvinyl chloride, or the like,
Alternatively, a substrate made of glass, metal, ceramic, or the like can be used. Further, it is preferable to use a light transmissive substrate.

The stimulus applying means 4 includes electrode layers such as conductive metal films such as gold, copper, silver, aluminum, indium tin oxide (ITO) and tin oxide, carbon materials, tantalum compounds, hafnium compounds and nichrome. Typical examples include a heating resistor layer and a light emitting layer such as a laser, an LED, and an EL. Such a stimulus-providing layer is preferably provided on a substrate.

The stimulus applied to the optical element of the present invention may be a natural stimulus or an artificial stimulus. If a natural stimulus such as light, heat, or a chemical substance is used, it can be used for a light control element, an optical shutter, a sensor, and the like. On the other hand, in the case of artificial stimulation, by providing a means for applying a stimulus such as heat, light, an electric field, or an electric current from inside or outside the element, the display element, the recording element, and the light modulation It can be applied to devices and the like.

Next, the dimming function, which is one of the functions of the stimuli-responsive composition of the present invention, will be described with reference to FIG. 3 shown as a capsule embodiment. FIG. 3A shows a state in which the stimulus-responsive polymer material contained in the stimulus-responsive polymer composition inside the capsule is dissolved. In this state, the polymer material and the liquid are homogeneously compatible with each other, so that the state is transparent. On the other hand, FIG. 3B shows a state in which the stimulus-responsive polymer material in the stimulus-responsive polymer composition is not dissolved. In this state, the composition becomes non-uniform and scatters light, resulting in a cloudy state. Therefore, a layer composed of a plurality of such stimuli-responsive capsules can freely control the amount of transmitted light and the state of light scattering by an external stimulus, and can exhibit a so-called dimming function. it can. Also, these two states are
It is also possible to realize reversibly and repeatedly.

Further, the change in optical density (color density) of a stimulus-responsive polymer composition containing a coloring material due to the application of a stimulus will be described with reference to FIG. FIG. 4A shows a state in which the stimulus-responsive polymer material is dissolved in the capsule composition containing the colored stimulus-responsive liquid containing the coloring material. In this state, since the coloring material contained in the stimuli-responsive liquid is uniformly dispersed, light can be efficiently absorbed and a high optical density can be exhibited. On the other hand, FIG.
3 shows an insoluble state of a stimuli-responsive polymer material in a stimuli-responsive liquid. In this state, the stimuli-responsive polymer material takes in most of the coloring material therein and precipitates or precipitates. In this state, in the process where the stimulus-responsive polymer material is insolubilized by the application of a stimulus, the coloring material is taken into the polymer material due to its high affinity with the polymer material, or It is formed by the colorant being chemically bonded to the material. In this case, the concentration of the coloring material in the polymer material is improved and becomes higher than the saturation absorption concentration.
Therefore, the amount of light absorbed per unit color material amount, that is, the light absorption efficiency decreases, and the optical density (light absorption) decreases as compared with the state shown in FIG. That is, it is possible to change the optical density by applying a stimulus. Such a coloring action was first found in the present invention. Further, the above two states can be reversibly repeated by an external stimulus. Further, the hue can be variously changed depending on the type of the coloring material used. In a layer constituted by using a plurality of such stimulus-responsive capsules, the color density and the wavelength and intensity of transmitted light can be variously controlled by applying a stimulus.

[0044]

The present invention will be described below in detail with reference to examples. Example 1 (Production of thermoresponsive polymer material) 0.05 g of azoisobutyronitrile (AIBN) was added as a polymerization initiator to a solution of 10 g of N-isopropylacrylamide dissolved in 40 ml of tetrahydrofuran, and this was added to a solution of 60 g. The polymerization reaction was carried out at 48 ° C. for 48 hours, and the reaction product was purified by precipitation with ethyl ether to obtain about 9.0 g of poly N-isopropylacrylamide (molecular weight: about 50,000). 1% by weight of the obtained poly N-isopropylacrylamide
An aqueous solution was prepared. When the temperature of the aqueous solution was gradually increased from 20 ° C. and its heat-sensitive properties were evaluated, the aqueous solution was in a transparent state at a low temperature, but undergoes a phase transition at about 31 ° C., became non-uniform, and became cloudy. It was confirmed that. This is because poly-N-isopropylacrylamide was insoluble in water and precipitated at 31 ° C. or higher. It was also found that when the temperature of the cloudy aqueous solution was lowered to a temperature lower than 31 ° C., the solution became transparent again and was reversible.

(Preparation of Stimuli-Responsive Polymer Composition) 0.1 g of poly N-isopropylacrylamide synthesized above
To which 10 g of distilled water was added. Other,
UV curable resin to which a polymerization initiator is added (Aronix U
V: Toa Gosei Co., Ltd.) to prepare a toluene solution containing 80% by weight. Next, the above-mentioned aqueous solution of poly-N-isopropylacrylamide was added to 20 g of the above-mentioned ultraviolet-curable resin solution, and an emulsion solution in which droplets of the aqueous solution were dispersed was prepared using a rotary stirring device.

The resulting emulsified solution is applied to a 100 μm-thick transparent polyester film using a blade coater, and is irradiated with ultraviolet light to be cured, whereby a 50 μm-thick stimulus-responsive polymer composition is obtained. A self-holding sample on which an object was formed was prepared. When this sample was observed under a microscope, an aqueous solution of the above-mentioned polymer material, which was isolated in a phase-separated state as a drop having a size in the range of 10 to 30 μm, was dispersed inside the obtained composition film. Confirmed that it exists.

(Evaluation of function)
Although it was almost transparent at 0 ° C, it was found that it became cloudy and opaque when heated to 40 ° C. When this sample was cooled again to 20 ° C., it returned to the initial transparent state, and it was found that the light transmittance reversibly changed. Observing these changes with a microscope, the stimulus-responsive polymer material in the composition film takes a dissolved state and an insoluble state (precipitation) as the temperature changes, and the insoluble state (40 ° C.)
Then it turned out to scatter light strongly. This sample is
Excellent repetition stability, fast response speed, and no liquid leakage or bubbles. In this way, it was confirmed that a solid stimulus-responsive polymer composition having self-holding properties and not causing liquid leakage was easily obtained. This sample has a very simple configuration and can be used as an optical element such as a temperature sensor or a light control element.

Example 2 (Production of Microcapsules Containing Stimuli-Responsive Polymer Material Solution) Microcapsules containing the polyN-isopropylacrylamide aqueous solution synthesized in Example 1 were produced by the interfacial polymerization method as follows. . First, 0.2 g of poly N-isopropylacrylamide was added to 0.4 M 1,6-
The solution charged in a mixture of 10 ml of an aqueous solution in which hexanediamine and 0.45 M sodium carbonate were dissolved and 10 ml of distilled water was saturated and swollen. This dispersion aqueous solution was added to 50 ml of a chloroform-cyclohexane mixed solution (volume ratio: 1/4) containing 5% by weight of Span85 (sorbitan trioleate) as a surfactant, and a well-stirred emulsion was obtained.

Next, a solution prepared by dissolving 0.4 g of terephthaloyl dichloride in 50 ml of the same mixed solution as described above was added to the emulsified solution with stirring to form a self-holding film on which a polyamide film was formed by an interfacial polymerization reaction. The microcapsules of the nature were obtained. The microcapsules were thoroughly washed with distilled water and dried. The average particle size of the obtained microcapsules was about 20 μm. This was observed with a microscope, and it was confirmed that a polymer aqueous solution was present inside the obtained microcapsules.

(Function Evaluation) Observation of the obtained microcapsules with a microscope equipped with a heating device showed that the microcapsules were almost transparent at 20 ° C.
It was found that heating to 0 ° C. turned cloudy and opaque. Further, it was found that when this was cooled again to 20 ° C., it returned to the initial transparent state and changed reversibly. This change has been found to occur at very high speeds of less than one second.
Observing this change with a microscope, the stimulus-responsive polymer material in the composition film takes a dissolved state and an insoluble state (precipitation) as its temperature changes, and in the insoluble state (40 ° C.) Was found to scatter strongly. Further, it was found that this microcapsule was extremely stable without liquid leakage or bubbles even after repeated heating and cooling.

Example 3 5 g of the microcapsules containing the aqueous solution of N-isopropylacrylamide prepared in Example 2 were well dispersed in 20 ml of a 10% aqueous solution of polyvinyl alcohol (PVA) used as a binder, and this was dispersed using a blade coater. A sample having a solid self-holding coating film having a thickness of about 50 μm was formed by applying the film on a transparent polyester film and drying.

It was found that the coating film of this sample was almost transparent at 20 ° C., but turned to cloudy and opaque when heated to 40 ° C. It was also found that when this was cooled again to 20 ° C., it returned to the initial transparent state, and the light transmittance reversibly changed. This sample was excellent in repetition stability, fast in response speed, and free of liquid leakage and bubbles. In this way, it was confirmed that a solid stimulus-responsive composition having self-holding properties and no liquid leakage was obtained. This sample has a very simple configuration and can be used as an optical element such as a temperature sensor or a light control element.

Example 4 (Production of thermoresponsive polymer material) A solution prepared by dissolving 9.8 g of N-isopropylacrylamide and 0.2 g of acrylic acid in 40 ml of tetrahydrofuran was used as a polymerization initiator for azoisobutyronitrile (AIBN). ) Was added, and the mixture was polymerized at 60 ° C for 48 hours, and the reaction product was precipitated and purified with ethyl ether to obtain a copolymer of N-isopropylacrylamide and acrylic acid (molecular weight: about 50,000). 9.0 g were obtained. A 1% by weight aqueous solution of the obtained copolymer was prepared, and the temperature of the aqueous solution was changed to evaluate the heat sensitivity. As a result, it was confirmed that the liquid crystal was in a transparent state at a low temperature, but a phase transition occurred at about 33 ° C., resulting in non-uniformity and cloudiness. This means that at 33 ° C. or higher, the copolymer was insoluble in water and precipitated. It was also found that when the temperature of the cloudy aqueous solution was lower than 33 ° C., it became transparent again and was reversible.

(Production of pigment-containing microcapsules) 0.2 g of the copolymer synthesized above and 0.1 g of a phthalocyanine pigment (blue) having a primary particle diameter of about 0.1 μm as a coloring material
Was added to 20 g of distilled water, and this was stirred and mixed to prepare an aqueous solution. Next, a self-holding composition microencapsulated was obtained in the same process as in Example 2 using the aqueous solution. The average particle size of the obtained microcapsules is about 20 μm
And blue. When this was observed with a microscope,
It was confirmed that a polymer aqueous solution containing a phthalocyanine pigment was present inside the obtained microcapsules.

(Evaluation of Function) The microcapsules prepared above were observed with a microscope equipped with a heating device. This microcapsule was found to be in a deep blue state at 20 ° C, but turned to a light blue state when heated to 40 ° C. When this was cooled again to 20 ° C., it was found that it returned to the initial dark blue state and changed reversibly. This change has been found to occur at very high speeds of less than one second. When this change was observed, the stimulus-responsive polymer material in the capsule was repeatedly in a dissolved state and an insoluble state (precipitation) due to the temperature change. Further, it was also found that the stimulus-responsive polymer material in the capsule was precipitated by being incorporated into the polymer material in the insoluble state (40 ° C.). This change in color is due to the fact that the pigment is evenly dispersed in the polymer material in the dissolved state, which increases the light absorption efficiency. Conversely, in the insoluble state (precipitation), the pigment is incorporated into the polymer material. It is thought that this occurs due to the concentration (aggregation) of light and the reduction of the light absorption efficiency. Furthermore, it was found that the microcapsules were extremely stable without liquid leakage or bubbles even after repeated heating and cooling. Based on these facts, the microcapsules can be used as a coloring material for expressing a color.

Example 5 (Production of Thermoresponsive Polymer Material Covalently Bonding Coloring Material)
9.5 g of isopropylacrylamide and the following structural formula 1
Anthraquinone-based polymerizable dye (blue) 0.5
g of azoisobutyronitrile (AIBN) as a polymerization initiator in a solution prepared by dissolving g in 40 ml of tetrahydrofuran.
0.05 g was added, and this was polymerized at 60 ° C. for 48 hours, and the reaction product was precipitated and purified with ethyl ether to obtain a copolymer thereof (molecular weight: about 50,000).
About 9.0 g were obtained.

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A 1% by weight aqueous solution of the obtained copolymer was prepared, and the temperature sensitivity of the aqueous solution was changed to evaluate the heat sensitivity. As a result, it was confirmed that the solution was a blue solution which was uniformly dissolved at a low temperature, but caused a phase transition at about 34 ° C. to become a heterogeneous solution. In addition, the temperature of this solution is set to 34
When the temperature was lower than ℃, it was uniform again, so that it had reversibility.

(Production of microcapsules) 20 g of distilled water was added to 0.2 g of the copolymer synthesized above, and the mixture was stirred and mixed to prepare a 1% by weight aqueous solution. Next, using the aqueous solution, a self-holding composition microencapsulated was prepared in the same manner as in Example 2. The resulting microcapsules had an average particle size of about 20 μm and were blue. This was observed with a microscope, and it was confirmed that a blue polymer aqueous solution was present inside the obtained microcapsules.

(Evaluation of Function) The microcapsules prepared above were observed with a microscope equipped with a heating device. This microcapsule was found to be in a deep blue state at 20 ° C, but turned to a light blue state when heated to 40 ° C. Further, when this was cooled again to 20 ° C., it returned to the initial dark blue state, and it was found that the color and the light transmittance changed reversibly. This change has been found to occur at very high speeds of less than one second. By observing this change, it was found that the stimuli-responsive polymer material in the capsule was repeatedly in a dissolved state and an insoluble state (precipitation) due to the temperature change. This change in color is due to the fact that in the dissolved state, the polymer material to which the coloring material is bonded is uniformly dissolved, so that the coloring material is in a diffusing state, so that the light absorption efficiency is high. It is considered that this occurs because the color material is concentrated (agglomerated) together with the polymer material and the light absorption efficiency is reduced. Furthermore, it was found that this microcapsule was extremely stable without liquid leakage or bubbles even when heating and cooling were repeated. Based on these facts, the microcapsules can be used as a coloring material for expressing a color.

Example 6 5 g of the colored microcapsules obtained in Example 4 was well dispersed in 10 g of an 80% toluene solution of an ultraviolet curable resin (Aronix UV: manufactured by Toagosei) containing a polymerization initiator used as a binder. Was. This dispersion solution was applied on a transparent polyester film having a thickness of 100 μm using a blade coater, and then cured by irradiating ultraviolet rays onto the transparent polyester film to prepare a sample on which a stimulus-responsive composition having a thickness of about 30 μm was formed. When the sample was observed with a microscope, it was confirmed that colored microcapsules were dispersed inside the obtained composition film.

This sample (film) exhibited a deep blue color at 20 ° C., but turned into a pale blue color when heated to 40 ° C. Further, when this was cooled again to 20 ° C., it turned out to be reversible because it changed to an initial blue color. When the change of the transmittance of this sample was measured by a spectrophotometer, it was found that the transmittance of light having a wavelength of 600 nm changed in a range from about 50% to 5%. In addition, this sample was excellent in repetition stability, fast in response speed, and free of liquid leakage and bubbles. In this way, it was confirmed that a solid stimuli-responsive composition having a color expression, a self-holding property, and no liquid leakage was obtained. This sample has a very simple configuration and can be used as an optical element such as a variable filter or a light control element.

Example 7 An optical element having the composition of the present invention formed on a substrate provided with a heating element was manufactured by the following steps. First, a partial (5 m) is placed at the center on a glass plate (10 mm × 10 mm square).
m × 5 mm square) indium oxide-tin oxide (ITO)
A substrate was formed on which a heating resistor composed of a thin film and a pair of aluminum thin film wirings connected to the ITO portion were formed. I of this substrate
The UV curable resin solution containing the microcapsules used in Example 6 was applied on the TO thin film by a masking method, and was cured to form a stimulus-responsive polymer composition layer having a thickness of about 30 μm. Further, a glass plate (10 mm × 10 mm square) was adhered thereon using an epoxy resin to produce an optical element having a stimulus-responsive composition layer sandwiched therebetween.

When the obtained optical element is energized, ITO
Since the thin film generated heat and the color density of the stimulus-responsive polymer composition layer decreased (changed from dark blue to light blue), it was confirmed that this optical element had a dimming function. In addition, when the current supply is stopped, the optical element returns to the initial state again, so that the optical element has excellent reversibility. From these facts, those in which a layer using the composition of the present invention is formed on a substrate provided with a stimulus applying means can express a color by stimulus and can change light transmittance. It has been found that a possible device is obtained.

Comparative Example 1 A 1% by weight aqueous solution of the poly (N-isopropylacrylamide) synthesized in Example 1 was prepared. On the other hand, two sheets 2m thick
A space of 1 mm is provided between glass (5 cm × 5 cm square) using a spacer having a thickness of 1 mm, and a cell whose edge is laminated with an epoxy resin is produced. Was prepared. When this sample was heated to 31 ° C. or more, it became uneven and clouded,
It was confirmed that the film became transparent again when cooled to 1 ° C. or less. The initial change was as fast as several seconds or less, but it was found that if the operation of heating and cooling was repeated many times, the speed required for the change became extremely slow and deteriorated to take several tens of seconds. When this was observed with a microscope, it was found that poly-N-isopropylacrylamide insolubilized by heating formed coarse aggregates, which reduced the response speed. This indicates that the composition of the present invention is superior to the conventional composition.

[0065]

The stimulus-responsive polymer composition of the present invention is obtained by separating a stimulus-responsive liquid, which is a mixture of a stimulus-responsive polymer material and a liquid, by a separating member such as a solid matrix such as resin or glass. Since the composition is held in a shape or a capsule, it is a self-holding composition that can be processed in various forms without hindering its stimulus response function. Therefore, the composition of the present invention does not require sandwiching or encapsulation between two substrates, which has been conventionally required, and has no liquid leakage or generation of bubbles. Can be enlarged.

Further, in the present invention, the stimulus-responsive polymer material is isolated as a minute area for each predetermined amount by the separating member and is held independently, so that the interaction between the polymer materials due to the change in the stimulus response. This has the advantage that the formation of coarse aggregates is suppressed and the response speed and stability can be maintained for a long period of time. Further, according to the present invention, since various colorants can be easily contained in the stimulus-responsive polymer material and the liquid, light control, display, and a recording medium of a desired color (color) are required. It can be easily manufactured accordingly.

[Brief description of the drawings]

FIG. 1 is a schematic structural view showing a form of a stimulus-responsive polymer composition of the present invention.

FIG. 2 is a configuration example of an optical element of the present invention.

FIG. 3 is a diagram illustrating a state of a stimuli-responsive polymer material in a stimuli-responsive polymer composition of the present invention.

FIG. 4 is a diagram illustrating a state of a stimulus-responsive polymer material and a colorant in a stimulus-responsive polymer composition of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Stimuli-responsive polymer composition, 3 ... Spacer, 4 ... Stimulus giving means.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // G02B 5/20 G02B 5/22 5/22 B01J 13/02 Z (72) Inventor Masato Mikami 1600 Takematsu, Minamiashigara-shi, Kanagawa Address Fuji Xerox Co., Ltd.

Claims (12)

[Claims] 1. A self-holding stimulus response comprising a region containing a stimulus-responsive polymer material whose liquid solubility changes by application of a stimulus and a liquid, and an isolation member surrounding the region. Polymer composition. 2. The stimulus-responsive polymer composition according to claim 1, wherein the separating member is a matrix. 3. The stimulus-responsive polymer composition according to claim 1, wherein the matrix includes a plurality of the regions. 4. The stimulus-responsive polymer composition according to claim 1, wherein the matrix is a polymer compound. 5. A stimulus, which is a microcapsule comprising a region containing a stimulus-responsive polymer material and a liquid whose solubility in a liquid is changed by application of the stimulus, and a polymer film surrounding the region. Responsive polymer composition. 6. A microcapsule having a region containing a stimulus-responsive polymer material and a liquid whose solubility in a liquid changes by the application of a stimulus, a microcapsule having a polymer film surrounding the region, and dispersing the microcapsule. A stimulus-responsive polymer composition comprising a matrix. 7. The microcapsules having an average particle size of 0.0
The stimulus-responsive polymer composition according to claim 5, wherein the composition ranges from 2 μm to 10 mm. 8. The stimulus-responsive polymer composition according to claim 1, wherein the separating member is light-transmitting. 9. The stimulus-responsive polymer composition according to claim 1, wherein the region contains a coloring material. 10. A self-holding stimulus responsiveness comprising a region containing a stimulus responsive polymer material whose solubility in a liquid is reversibly changed by application of a stimulus and a liquid, and an isolation member surrounding the region. An optical element formed using a polymer composition. 11. The optical element according to claim 10, wherein the stimulus-responsive composition is provided on a substrate or between substrates. 12. The optical element according to claim 11, wherein a means for applying heat, an electric field, a current, or light is provided on the substrate.