JP2003321513A - Polymeric gel and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymeric gel for use in display devices with high display performance. <P>SOLUTION: The polymeric gel is represented by the general formula (1) (wherein, A is a recurring unit having the function of giving excitation; B is a recurring unit having the function of forming the polymeric gel; C is a crosslinking group-bearing recurring unit; x, y and z each denotes mol% such that 0.1≤x≤99.9, 0.1≤y≤99.9, 0≤z≤99.8, wherein x+y+z=100). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polymer gel containing a repeating unit having a function of supplying a stimulus and a repeating unit having a function of forming a polymer gel, and the polymer gel and the function of developing a color by the stimulation. And a display device using the compound.

[0002]

2. Description of the Related Art Papers capable of reversibly displaying digital information, so-called digital papers, are now being actively researched because their importance in the future digital information age will increase. Typical methods include an electrophoretic display method based on the movement of charged fine particles, a thermal rewritable display method using the thermally reversible coloring process of a leuco dye, and a method using the volume expansion of a polymer gel. To be

Among them, the thermal rewritable display method utilizing the thermal reversible color development process of leuco dyes has been extensively studied because white display based on scattering similar to paper can be used.

Leuco dyes are widely used as various display materials because they can form a color system by an acid-base reaction, and examples thereof include heat-sensitive paper, pressure-sensitive paper, and heat-sensitive print materials. Furthermore, since the leuco dye is capable of a reversible color development system of an acid-base reaction, for example, a reversible thermosensitive display material in combination with a developer is known. As the reversible thermosensitive display material, for example, Polymer Preprints, Japan. Volume 42,
It is disclosed on page 736, 1993.

As a material in which a leuco dye and a color developer are linked to a polymer by a covalent bond, there is disclosed in JP-A-11-181031.
Nos. Nos. 3,849,697, and 6-26, but the present invention relates to an irreversible display material in combination with a functional group having an acid multiplication function.

On the other hand, display methods utilizing the phase change of polymer gel are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 11-236559 and 9-160081.

As a technique for compounding a polymer gel and an optical functional material, a polymer gel having a residue capable of ion dissociation upon irradiation with light is disclosed in JP-A-62-55967.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is achieved by combining a polymer gel having a stimulus-providing group and a compound capable of forming a color upon stimulation. An object of the present invention is to provide a display device having high color display stability and improved display contrast and high display performance.

[0009]

The above-mentioned problems have been solved by the following means. [1] A polymer gel represented by the general formula (1). General formula (1)

[0010]

[Chemical 2]

In the formula, A represents a repeating unit having a function of supplying a stimulus, B represents a repeating unit having a function necessary for forming a polymer gel, and C represents a repeating unit having a crosslinking group. x, y and z represent mol%, and 0.1 ≦
x ≦ 99.9, 0.1 ≦ y ≦ 99.9, 0 ≦ z ≦ 99.
8, x + y + z = 100. [2] In the polymer gel represented by the general formula (1),
A polymer gel in which A has a phenol skeleton. [3] In the polymer gel represented by the general formula (1),
The polymer gel according to [1] or [2], wherein A is a repeating unit represented by the general formula (2). General formula (2)

[0012]

[Chemical 3]

In the formula, Link A represents a divalent linking group or a single bond. Phenol represents a phenol skeleton. R ₁ represents a hydrogen atom or an alkyl group. m represents mol% and 0.1 ≦ m ≦
It is 99.9.

[4] In the polymer gel represented by the general formula (1), B is a repeating unit composed of acrylic acid, acrylic ester, acrylamide or N-alkylacrylamide [1], The polymer gel according to [2] or [3]. [5] In the polymer gel represented by the general formula (1),
A is a repeating unit represented by the general formula (2) and B is a repeating unit represented by the general formula (3). [1] to [4] Molecular gel.
General formula (3)

[0015]

[Chemical 4]

In the formula, R ₂ has the same meaning as R ₁ , and R ₃ and R ₄ each represent a hydrogen atom, an alkyl group or an aryl group. n represents mol% and is 0.1 ≦ n ≦ 99.9. [6] A display device having a layer containing the polymer gel according to any one of [1] to [5]. [7] The display device according to [6], which has a layer containing a polymer gel on a support. [8] The display device according to [6], which has a layer containing a polymer gel between a pair of substrates.

[9] The display device according to any one of [6] to [8], further including an external light source. [10] The layer containing a polymer gel contains a compound having a function of developing a color upon stimulation [6]
~

The display device according to any one of [9]. [11] The display device according to [10], wherein the compound having a function of developing color upon stimulation is a leuco dye.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In addition, in this specification, "-" shows the range including the numerical value described before and behind that as a minimum value and a maximum value, respectively.

The polymer gel used in the present invention is defined to exhibit a substance form intermediate between a solid and a liquid, in which a polymer solid and a solvent liquid coexist. (Meta) means both a compound name containing meta and a compound name not containing meta. For example, (meth) acrylic acid means methacrylic acid and acrylic acid. The constituents of the polymer gel may be any, but (meth) acrylamide derivatives (for example, acrylamide, methylacrylamide, ethylacrylamide, n-propylacrylamide, isopropylacrylamide, n-butylacrylamide, tert-butylacrylamide, Cyclohexyl acrylamide, benzyl acrylamide, hydroxymethyl acrylamide, methoxyethyl acrylamide,
Dimethylaminoethyl acrylamide, phenyl acrylamide, dimethyl acrylamide, diethyl acrylamide, β-cyanoethyl acrylamide, N- (2-
Acetoxyethyl) acrylamide, diacetone acrylamide, dimethylaminopropyl acrylamide and methacrylamides corresponding to the above acrylamides), hydroxyethyl (meth) acrylate, (meth) acrylic acid, maleic acid, pinylpyrrolidone, vinyl pyridine, vinyl Sulfonic acid, vinylbenzenesulfonic acid, acrylic acid alkyl ester, styrene derivative,
Polymers such as vinylcarbazole derivatives, vinyl alcohol, and alkyl-substituted cellulose derivatives, their copolymers,
Examples thereof include crosslinked products thereof and metal salts thereof. The polymer gel used in the present invention is preferably N-alkyl-substituted (meth) acrylamide, poly (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, a polymer composed of vinyl sulfonic acid, and copolymer. Examples thereof include coalesced products, crosslinked products thereof, and metal salts thereof. Particularly preferably, N-alkyl-substituted (meth) acrylamide, poly (meth) acrylic acid, (meth) acrylic acid, (meth)
A polymer, a copolymer, a cross-linked product thereof, or a metal salt thereof made of an acrylic ester.

To introduce the crosslinked structure, a method of irradiating a copolymer using a crosslinking precursor monomer of N-hydroxymethylacrylamide or N-alkoxymethylacrylamide with heat, ultraviolet rays or radiation, or a polyfunctional monomer is used. Examples thereof include a method using a body (for example, N, N′-methylenebis (meth) acrylamide, bishydroxyethyl (meth) acrylate, divinylbenzene, etc.).

The polymer gel of the present invention has a molecular weight of 1,000.
The range is preferably from 1 to 1,000,000, particularly preferably from 2000 to 100,000. Further, the polymer gel may be in any form such as a random copolymer, an alternating copolymer and a block copolymer.

The solvent constituting the gel may be any solvent as long as it can form the polymer gel of the present invention, but preferably water, alcohols (methanol,
Ethanol, propanol, butanol, etc., halogenated hydrocarbons (chloroform, dichloromethane, dichloroethane, etc.), aromatic hydrocarbons (benzene, toluene, xylene, etc.), aliphatic hydrocarbons (hexane, etc.), ethers (diethyl) Ether, tetrahydrofuran etc.), ketones (acetone, methyl ethyl ketone etc.), esters (acetic acid ethyl ester etc.), amides (dimethylformamide, dimethylacetamide etc.), sulfoxides (dimethyl sulfoxide etc.),
Nitriles (acetonitrile, benzonitrile, etc.) and the like are preferable. A solvent having a high dielectric constant is preferable, and examples thereof include water, alcohols, ketones, esters, amides, sulfoxides, and nitriles. Moreover, you may use these solvents in combination of 2 or more types. The mixing ratio may be any. The amount of solvent contained in the gel is not limited. The ratio (mass ratio) of the solvent to the dry mass of the gel is gel: solvent =
1: 1 to 1: 10000 is preferable, and 1: 1 to 1:
The range of 1000 is more preferable.

Next, the repeating unit having the function of supplying the stimulus represented by A will be described. A is preferably
It is a repeating unit having a function of supplying a stimulus to reversible color development. The repeating unit represented by A is preferably a repeating unit obtained by polymerization of a polymerizable compound in which a functional site that supplies a stimulus and a polymerizable group are linked by a covalent bond. A vinyl group is mentioned as a preferable polymerizable group. A phenol skeleton is preferable as the functional site for supplying a stimulus.

Examples of the stimulus include acid-base, heat, pressure, electric field, magnetic field, light and the like, but acid-base, heat and electric field are preferable. Particularly preferred is an acid. Examples of the compound having a function of supplying an acid include a phenol derivative, a salicyl derivative, an aromatic carboxylic acid, a sulfonic acid derivative, urea, thiourea, acid clay, pentonite, a novolac resin, and a metal complex. Specific examples of these include, for example, Paper Pulp Technology Times (19
1985) those described on pages 49 to 54 and 65 to 70, Japanese Examined Patent Publication Nos. 40-9309 and 45-14039,
Japanese Patent Laid-Open Nos. 52-140483 and 48-51510,
57-210886, 58-87089, 5
9-112286 and 60-176795.

Any compound may be used as a compound exhibiting reversible color development having a function of reversibly developing color upon stimulation, but preferably, a reversible conversion between a dye precursor called a leuco dye and a dye is utilized. Those that do are preferred.
Chemistry and Applications of leuco dyes
Leuco Dyes (edited by R. Muthyala, Plenum Press, 1997)
The chromophore described in, i.e., phthalide, fluorane, triarylmethane, spiropyran, triazene, pyridine, pyrazine, phenothiazine, leuco auramine, fluorene, etc.
Preferably Chemistry and Applications of Leuco Dy
es (R. Muthyala ed., Plenum Press, 1997), phthalide chromophore described on page 97, fluoran chromophore described on page 159.

Specific examples of the phthalide compound include:
US Pat. Nos. 3,491,111 and 3,491,1
No. 12, No. 3,491, 116, No. 3,509,
No. 174, and the like. Specific examples of the fluoran compound include U.S. Pat. No. 3,624,10.
No. 7, No. 3,627,787, No. 3,641,0
No. 11, No. 3,462,828, No. 3,681,
No. 390, No. 3,920,510, No. 3,95
Examples thereof include those described in No. 9,571. Examples of the spiropyran compound include U.S. Pat. No. 3,971,808.
The items described in No. Examples of the pyridine-based and pyrazine-based compounds include U.S. Pat. No. 3,775,424.
No. 3,853,869, No. 4,246,31
The thing described in No. 8 is mentioned.

Next, the repeating unit having the function of forming the polymer gel represented by B will be described. Any repeating unit having a function of forming a polymer gel may be used, and examples thereof include (meth) acrylamide derivatives (eg, acrylamide, methylacrylamide, ethylacrylamide, n-propylacrylamide, isopropylacrylamide, n- Butyl acrylamide, tert-butyl acrylamide, cyclohexyl acrylamide, benzyl acrylamide, hydroxymethyl acrylamide, methoxyethyl acrylamide,
Dimethylaminoethyl acrylamide, phenyl acrylamide, dimethyl acrylamide, diethyl acrylamide, β-cyanoethyl acrylamide, N- (2-
Acetoxyethyl) acrylamide, diacetone acrylamide, dimethylaminopropyl acrylamide and methacrylamides corresponding to the above acrylamides), hydroxyethyl (meth) acrylate, (meth) acrylic acid, maleic acid, pinylpyrrolidone, vinyl pyridine, vinyl Sulfonic acid, vinylbenzenesulfonic acid, acrylic acid alkyl ester, styrene derivative,
Examples thereof include repeating units obtained by polymerization of vinylcarbazole derivatives, vinyl alcohol, alkyl-substituted cellulose derivatives and the like. Preferably, N-alkyl-substituted (meth) acrylamide, poly (meth) acrylic acid,
It is a repeating unit obtained by polymerization of (meth) acrylic acid ester, (meth) acrylamide, and vinyl sulfonic acid.

Next, the repeating unit having a crosslinking group represented by C will be described. The method for introducing the crosslinking group may be any method, but N-hydroxymethylacrylamide, a copolymer using a crosslinking precursor monomer of N-alkoxymethylacrylamide is heated, irradiated with ultraviolet rays or radiation. A method or a method using a polyfunctional monomer (for example, N, N′-methylenebis (meth) acrylamide, bishydroxyethyl (meth) acrylate, divinylbenzene, etc.) can be mentioned. Preferably,
It is a repeating unit obtained by polymerization of a polyfunctional monomer.

X, y and z each represent mol% and are 0.1
≦ x ≦ 99.9, 0.1 ≦ y ≦ 99.9, 0 ≦ z ≦ 9
9.8, x + y + z = 100. The ratio of x and y may be any, but x: y = 1: 1 in molar ratio.
The range of 0.1 to 1: 100 is preferable, and the range of x: y = 1: 1 to 1:10 is particularly preferable. The preferred range of z is 0 to 20, particularly preferably 0 to 10.

Next, the general formula (2) will be described. Link
A represents a divalent linking group or a single bond. The divalent linking group represented by LinkA is an atomic group composed of carbon atoms, nitrogen atoms, sulfur atoms, and oxygen atoms. As the divalent linking group, a single bond, an alkylene group having 1 to 20 carbon atoms (for example, methylene, ethylene, propylene, butylene, pentylene, cyclohexane-1,4-diyl),
Alkenylene group having 2 to 20 carbon atoms (eg, ethenylene), alkynylene group having 2 to 20 carbon atoms, amide group, ether group, ester group, sulfamide group, sulfonate group, ureido group, sulfonyl group , A sulfinyl group, a thioether group, a carbonyl group, a —NR— group (wherein R represents a hydrogen atom or an alkyl group or an aryl group), an arylene group having 6 to 40 carbon atoms (eg, 1,4-phenylene, 1 , 3-phenylene, 1,2-phenylene, 1,4-naphthylene,
4,4′-biphenylene), a heteroarylene group having 1 to 30 carbon atoms (eg, pyridine-2,4-diyl, thiophene-2,4-diyl, furan-2,4-diyl), an azo group, an azoxy group, a heterocycle Examples thereof include a divalent linking group having 0 to 60 carbon atoms, which is formed by combining one or more divalent groups (for example, piperazine-1,4-diyl group). These linking groups may further have a substituent. Examples of the substituent include the substituent group V.

Substituent group V: 1 to 30 carbon atoms, preferably 2 to 20 carbon atoms, and more preferably 3 to 10 carbon atoms.
An alkylsilyl group of (for example, trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl,
(Tripentylsilyl), a halogen atom (eg chlorine, bromine, iodine, fluorine), a mercapto group, a cyano group, a carboxyl group, a phosphoric acid group, a sulfo group, a hydroxy group, a carbon number of 1 to 10, preferably a carbon number of 2 to 8. , More preferably a carbamoyl group having 2 to 5 carbon atoms (eg methylcarbamoyl, ethylcarbamoyl, morpholinocarbamoyl), 0 to 10 carbon atoms, preferably 2 to 8 carbon atoms,
More preferably, a sulfamoyl group having 2 to 5 carbon atoms (for example, methylsulfamoyl, ethylsulfamoyl, piperidinosulfamoyl), a nitro group, and 1 to 2 carbon atoms.
0, preferably an alkoxy group having 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms (eg, methoxy, ethoxy, 2-methoxyethoxy, 2-phenylethoxy),
Aryloxy group having 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms (eg phenoxy, p-methylphenoxy, p-chlorophenoxy, 1-naphthoxy), 1 to 20 carbon atoms. , Preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms
An acyl group (eg, acetyl, benzoyl, trichloroacetyl) having 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, and more preferably an acyloxy group having 2 to 8 carbon atoms (eg acetyloxy, benzoyloxy), 1 carbon atoms. To 20, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms acylamino group (eg acetylamino), 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms. A sulfonyl group (eg, methanesulfonyl, ethanesulfonyl, benzenesulfonyl), a C 1-20, preferably a C 1-10, and more preferably a C 1-8 sulfinyl group (eg, methanesulfinyl, ethanesulfinyl, benzenesulfinyl). ), An amino group, a carbon number of 1 to 20, preferably Substituted amino groups having 1 to 12, more preferably 1 to 8 carbon atoms (eg, methylamino, dimethylamino, benzylamino, anilino, diphenylamino, 4-methylphenylamino, 4-ethylphenylamino, 3-n-propyl) Phenylamino, 4-n-propylphenylamino, 3-n-butylphenylamino, 4-n-butylphenylamino, 3-n-pentylphenylamino, 4-n-
Pentylphenylamino, 3-trifluoromethylphenylamino, 4-trifluoromethylphenylamino,
2-pyridylamino, 3-pyridylamino, 2-thiazolylamino, 2-oxazolylamino, N, N-methylphenylamino, N, N-ethylphenylamino), 0 to 15 carbon atoms, preferably 3 to 10 carbon atoms, More preferably, an ammonium group having 3 to 6 carbon atoms (eg, trimethylammonium, triethylammonium), 0 to 15 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms (eg, trimethylhydrazino). Group), a ureido group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms (for example, ureido group, N, N-dimethylureido group), 1 to 15 carbon atoms, preferably An imide group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms (for example, a succinimide group), or 1 carbon atom 20, preferably a carbon number of 1 1
2, more preferably an alkylthio group having 1 to 8 carbon atoms (eg methylthio, ethylthio, propylthio), an arylthio group having 6 to 80 carbon atoms, preferably 6 to 40 carbon atoms, more preferably 6 to 30 carbon atoms (eg phenylthio). , P-methylphenylthio, p-chlorophenylthio, 2-pyridylthio, 1-naphthylthio, 2-
Naphthylthio, 4-propylcyclohexyl-4'-biphenylthio, 4-butylcyclohexyl-4'-biphenylthio, 4-pentylcyclohexyl-4'-biphenylthio, 4-propylphenyl-2-ethynyl-
4'-biphenylthio), 1 to 80 carbon atoms, preferably 1 to 40 carbon atoms, and more preferably 1 to 30 carbon atoms.
A heteroarylthio group (eg, 2-pyridylthio, 3
-Pyridylthio, 4-pyridylthio, 2-quinolylthio, 2-furylthio, 2-pyrrolylthio), an alkoxycarbonyl group having 2 to 20 carbon atoms, preferably 2 to 12 carbon atoms, and more preferably 2 to 8 carbon atoms (eg, methoxycarbonyl). , Ethoxycarbonyl, 2-benzyloxycarbonyl), a carbon number 7 to 20, preferably a carbon number 7 to 12, and more preferably a carbon number 7 to 10 aryloxycarbonyl group (eg, phenoxycarbonyl), a carbon number 1 to 18, Preferably 1 to 1 carbon atoms
0, more preferably an unsubstituted alkyl group having 1 to 5 carbon atoms (eg, methyl, ethyl, n-propyl, isopropyl,
n-butyl, n-pentyl, n-hexyl), 1 to 1 carbon atoms
A substituted alkyl group having 8, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms (eg hydroxymethyl, trifluoromethyl, benzyl, carboxyethyl, ethoxycarbonylmethyl, acetylaminomethyl, and here 2 carbon atoms) To 18, preferably 3 to 10, more preferably 3 to 5 carbon atoms of an unsaturated hydrocarbon group (eg, vinyl group, ethynyl group 1-cyclohexenyl group, benzylidene group, benzylidene group) is also included in the substituted alkyl group. , 6 to 20 carbon atoms,
Preferably 6 to 15 carbon atoms, more preferably 6 carbon atoms
To 10 substituted or unsubstituted aryl groups (eg phenyl, naphthyl, p-carboxyphenyl, p-nitrophenyl, 3,5-dichlorophenyl, p-cyanophenyl, m-fluorophenyl, p-tolyl, 4-propylcyclohexyl). -4'-biphenyl, 4-butylcyclohexyl-4'-biphenyl, 4-pentylcyclohexyl-4'-biphenyl, 4-propylphenyl-2-
Ethynyl-4′-biphenyl), a substituted or unsubstituted heteroaryl group having 1 to 20 carbon atoms, preferably 2 to 10 carbon atoms, and more preferably 4 to 6 carbon atoms (for example, 3-
Pyridyl, 5-methyl-3-pyridyl, 2-thienyl,
2-furyl, morpholino, tetrahydrofurfuryl).
These substituent groups V can have a structure in which a benzene ring or a naphthalene ring is condensed. Further, these substituents may be further substituted with the substituents described in the explanation of V so far. The substituent is preferably an alkyl group, an aryl group, an alkoxy group, an aryloxy group,
An amino group, an alkylamino group, an arylamino group, a halogen atom, a hydroxy group, and an alkoxycarbonyl group.

LinkA is preferably an alkylene group, an alkylene group having an ether group, an alkylene group having an ester group, or an alkylene group having an amide group.

R ₁ represents a hydrogen atom or an alkyl group. Examples of the alkyl group include those described in the above substituent group V. R ₁ is preferably a hydrogen atom or a methyl group.

The phenol skeleton is a phenol having a substituent and includes the following. Alkyl,
Phenol substituted with a single substituent which is any one of allyl, halogen atom, halo-substituted alkyl, cycloalkyl, phenyl, halo-substituted phenyl, alkyl-substituted phenyl, biphenylyl, benzyl or α-alkylbenzyl group; 2 of 2 or 3 substituents are 2,
Phenols substituted with 2 or 3 substituents in such a single substituent, except at the 6-position; tetramethyl or tetrahalo substituted phenols; or each of the above having a secondary hydroxy group on the phenol. Phenol substituted with a substituent is preferable, and examples of the compound having a phenol skeleton include 2,2′-bis (4-hydroxyphenyl) propane, 4-t-butylphenol, 4-
Phenylphenol, 4-hydroxydiphenoxide,
1,1′-bis (3-chloro-4-hydroxyphenyl) cyclohexane, 1,1′-bis (4-hydroxyphenyl) cyclohexane, 1,1′-bis (3-chloro-4-hydroxyphenyl) -2 -Ethylbutane,
4,4'-sec-isooctylidene diphenol,
4,4'-sec-butylidene diphenol, 4-te
Examples thereof include rt-octylphenol, 4-p-methylphenylphenol, 4,4′-methylcyclohexylidenephenol, 4,4′-isopentylidenephenol, and benzyl p-hydroxybenzoate, and the following salicylic acid derivatives. , For example, 4-pentadecyl salicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (tert-octyl) salicylic acid,
5-octadecylsalicylic acid, 5-α- (p-α-methylbenzylphenyl) ethylsalicylic acid, 3-α-methylbenzyl-5-tert-octylsalicylic acid, 5-
Tetradecylsalicylic acid, 4-hexyloxysalicylic acid, 4-cyclohexyloxysalicylic acid, 4-decyloxysalicylic acid, 4-dodecyloxysalicylic acid, 4
-Pentadecyloxysalicylic acid, 4-octadecyloxysalicylic acid, etc., and zinc, aluminum,
Examples include calcium, copper and lead salts.

Preferred specific examples of the phenol skeleton are shown below, including the bonding position.

[0035]

[Chemical 5]

Each m represents a mol% and 1 ≦ m ≦ 99. The preferable range of m is 1 to 50, and the particularly preferable range is 1 to 20.

As the method for producing the polymer gel of the present invention,
Any method may be used, but a method of crosslinking the polymer at the same time as the formation of the polymer or a method of crosslinking the polymer later is preferable. As a method of crosslinking at the same time as the production of the polymer, copolymerization of various vinyl monomers and a crosslinking monomer such as a divinyl compound, or polycondensation with a polyfunctional monomer can be used. As a method of cross-linking the polymer later, a method of acting a polymer having a different charge from each other to form an ion complex or a method of allowing a polymer and a cross-linking agent such as dialdehyde, dicarboxylic acid or diepoxide to act, light And a crosslinking reaction by radiation can be used. Specifically, functional gel (Aizo Yamauchi, Kyoritsu Shuppan, 1990), gel-
Basics and applications of soft materials (Yoshihito Nagata, industrial books,
The method described in (1991) is helpful.

Specific compound examples of the present invention are shown below, but the present invention is not limited thereto.

[0039]

[Chemical 6]

[0040]

[Chemical 7]

[0041]

[Chemical 8]

[0042]

[Chemical 9]

A display device including the polymer gel represented by the general formula (1) of the present invention will be described.
In the display device of the present invention, the gel is in a colored state when the polymer gel is swollen in a solvent containing the leuco dye and the leuco dye receives a stimulus necessary for coloring the leuco dye from the site represented by A. Becomes On the other hand, when the solvent is released from the polymer gel, the interaction between the site represented by A and the leuco dye is reduced, which results in a colorless state. Reversible color development can be performed by reversibly carrying out and releasing the solvent in such a polymer gel. The polymer gel exhibits a material form intermediate between the solid and the liquid, in which a solid that is a polymer and a liquid that is a solvent coexist, and the amount of the solvent contained therein can be changed according to the stimulus. A typical stimulus is
Examples include heat, pH, electric field, light, and change of solvent species.
Preference is given to changing the heat, electric field or solvent species. Particularly preferable is heat.

The display device of the present invention may be either reversible display or irreversible display, but reversible display is preferred. Any method can be used to enable such reversible color development, but it is preferable to utilize the difference in swelling property due to the solvent change of the polymer gel.

The display device of the present invention is used as a light control material for controlling the amount of light transmission, a display device for displaying an image, a temperature sensor for displaying temperature, and a sensor for detecting a specific chemical substance. be able to. Specifically, JP-A-6-175165 and JP-A-6-4021
JP-A-62-60690, JP-A-63-3027
No. 9, JP-A-5-132640, and JP-A-5-1484.
42 and the display device described in JP-A-6-341957 can be used.

[0046]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

Example 1 (Synthesis of Exemplified Compound 1-4 of the Present Invention)

[0048]

[Chemical 10]

The compound (M-1) was synthesized according to the above scheme. Synthesis of Exemplified Compound (1-4) 2.0 g of N-isopropylacrylamide, Compound (M-
1) 2.0 g of a tetrahydrofuran solution of 2.0 g of compound (M-2) in 20 ml of nitrogen was added with 20 mg of azobisisobutyronitrile (AIBN) as an initiator under a nitrogen atmosphere,
The reaction was carried out at 60 ° C. for 12 hours with stirring. The reaction solution was poured into a large amount of hexane solution, the precipitated solid content was filtered off,
Wash with hexane. The obtained polymer was dissolved in tetrahydrofuran (THF), and then a large amount of hexane was added to obtain a precipitated solid content. The solid content obtained by repeating this operation was dissolved in water to obtain Exemplified Compound 1-4 as the polymer gel of the present invention. Yield of solids 2.2g Number average molecular weight (Mn) of solids 5400 (GPC method, polystyrene conversion)

Example 2 (Display Device of the Present Invention) The exemplified compound (1-4) (aqueous solution) of the present invention is a transparent solution. Next, when a methanol solution containing a leuco dye (L-1) was added to this aqueous solution, the color of the solution changed to blue. It was confirmed that this color-developed state was uniform from any angle, and that it did not have the viewing angle dependence as seen in liquid crystal displays. Next, when this solution was subjected to a dialysis treatment with water, the solution of the exemplary compound (1-4) of the present invention changed into a transparent state again. This reversible color development is based on the presence or absence of the leuco dye in the solvent contained in the gel.

[0051]

[Chemical 11]

Next, the exemplary compound (1-4) (aqueous solution) of the present invention was applied onto PET and dried to form a transparent film. When a methanol solution containing a leuco dye (L-1) was dropped onto the film and dried, only the dropped portion developed a blue color. That is, image display was possible.

[0053]

EFFECT OF THE INVENTION By using the polymer gel of the present invention, it is possible to change between a reversible colored state and a colorless state based on the presence or absence of a leuco dye, and since it is based on a chemical change, the contrast is good and a large area is obtained. It is possible to efficiently provide a low-cost display device that is easy to realize and has good visibility.

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Claims (2)

[Claims] 1. A polymer gel represented by the following general formula (1). General formula (1) In the formula, A represents a repeating unit having a function of supplying a stimulus, B represents a repeating unit having a function of forming a polymer gel, and C represents a repeating unit having a crosslinking group. x, y
And z each represent mol%, and 0.1 ≦ x ≦ 99.9,
0.1 ≦ y ≦ 99.9, 0 ≦ z ≦ 99.8, x + y + z
= 100. 2. A display device having a layer containing a polymer gel represented by the general formula (1).