JP3274170B2 - Reversible thermochromic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color material which reversibly changes color in response to a change in temperature, and more particularly to a reversible thermochromic material having improved light resistance.

[0002]

2. Description of the Related Art A reversible thermochromic material changes its color when it is exposed to a predetermined temperature or more, and is used for articles requiring proper temperature, warning and danger temperature indications, and commodities that enjoy color change. The coloring material of the present invention can be used for, for example, frozen, refrigerated and heated foods and drinks, writing utensils, stationery such as postcards, clothing and toys. Conventionally, as a reversible thermochromic material, it is composed of three components: one that uses a metal complex salt crystal, one that uses a cholesteric liquid crystal, a compound that has an electron-donating color former, a compound that has a phenolic hydroxyl group, and a compound that has an alcoholic hydroxyl group. Compositions (for example,
No. 1-444706, JP-B-51-44709), and a composition comprising three components such as phthales or fluoresceins, an electron-donating organic nitrogen compound, and an alcohol or acid amide (for example, JP-B-57-65772).
And a composition containing a polyhydroxy compound, an alkali metal borate, and a pH-indicating dye are known.

[0003] Among these reversible thermochromic materials, those using crystals of metal complex salts are excellent in heat resistance and light resistance, and are used for some industrial purposes. However, there is a disadvantage that the color hue is high. Cholesteric liquid crystals are used for thermometers, ornaments, daily necessities, etc.
Moreover, there is a disadvantage that the life of discoloration is short. A combination of an electron-donating color former (hereinafter, referred to as a color former) and 2,2-bis (4-hydroxyphenyl) propane (hereinafter, referred to as bisphenol A) is widely used for stationery, toys, clothing, and the like. I have. In recent years, more and more cases have been used for outdoor use, and attempts have been made to improve the light resistance by adding an ultraviolet absorber, an antioxidant, an antioxidant and the like. However, the above-mentioned additives have problems such as low solubility in a nonvolatile hydrophobic compound having an arbitrary melting point typified by a higher alcohol, and little effect unless the amount of the additive is large. In addition, a composition comprising three components of phthales or fluoresceins, an electron donating organic nitrogen compound, and an alcohol or an acid amide has few types of coloring hues, a polyhydroxy compound, an alkali metal borate, and a pH.
Combinations with indicator dyes have the disadvantage that the discoloration temperature is high and the response of the discoloration takes time, which limits their use.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a reversible thermochromic material which has a fast response to changes due to heat and has remarkably improved light fastness.

[0005]

Means for Solving the Problems The present inventors have conducted various studies to achieve the above object, and as a result, completed the present invention. That is, the present invention provides (a) an electron-donating color former, (b)
A reversible thermochromic material containing an electron-accepting compound, (c) a nonvolatile hydrophobic compound having an arbitrary melting point, and (d) further containing at least one compound represented by the general formula (1) And a reversible thermochromic material.

[0006]

Embedded image (Wherein R ₁ and R ₂ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R ₁ and R ₂ may form a ring; R ₃ , R ₄ , R ₅ , R ₆ are a hydrogen atom, a chlorine atom, a chain alkyl group having 1 to 8 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, a hydroxyl group, and R ₇ is a hydrogen atom or a chain alkyl group having 1 to 4 carbon atoms. , R ₈ is a hydrogen atom,
A chain alkyl group having 1 to 20 carbon atoms, a cyclic alkyl group having 5 to 7 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, and 7 carbon atoms
~ 20 aralkyl, phenyl, naphthyl, and heteroaromatic groups)

Further, the present invention relates to non-volatile hydrophobic compounds having an arbitrary melting point, such as alcohols, esters,
The above-described reversible thermochromic material using at least one selected from ethers, ketones, carboxylic acids or acid amides, (a) an electron-donating color former, (b) an electron-accepting compound, and (c) The present invention relates to a non-volatile hydrophobic compound having an arbitrary melting point, and (d) a reversible thermochromic material in which a component comprising the compound represented by the general formula (1) is encapsulated in a microcapsule wall film. The compound represented by the general formula (1) according to the present invention has a phenolic hydroxyl group and a carbamate group in the molecule, and the substitution position of the hydroxyl group and the carbamate group is -CR ₁ R _2-. Each of the groups may be in the ortho, meta or para position, preferably in the meta or para position, and more preferably in the general formula (1-
a), (1-b), and (1-c).

[0008]

Embedded image (Wherein, R _{1 to} R ₈ are the same as in the case of formula (1))

Specific examples of the compound represented by the general formula (1) according to the present invention include, but are not limited to, the following compounds. Compound No. of compound 1.2 (4'-hydroxyphenyl) -2- (4 "- methoxycarbonyl A Minofeniru) propane 2,2 (4'-hydroxyphenyl) -2- (4" - ethoxycarbonyl Aminophenyl) propane 3.2- (4'-hydroxyphenyl) -2- (4 "-n-propoxycarbonylaminophenyl) propane 4.2- (4'-hydroxyphenyl) -2- (4" -iso Propoxycarbonylaminophenyl) propane 5.2- (4'-hydroxyphenyl) -2- (4 "-n-butoxycarbonylaminophenyl) propane 6.2- (4'-hydroxyphenyl) -2- ( 4 "-isobutoxycarbonylaminophenyl) propane 7.2- (4'-hydroxyphenyl) -2- (4" -sec-butoxycarbonyl L-aminophenyl) propane 8.2- (4'-hydroxyphenyl) -2- (4 "-n-pentyloxycarbonylaminophenyl) propane 9.2- (4'-hydroxyphenyl) -2- (4" -N-hexylcarbonylaminophenyl) propane 10.2- (4'-hydroxyphenyl) -2- (4 "-2-ethylhexylcarbonylaminophenyl) propane

11.2- (4′-Hydroxyphenyl) -2- (4 ″ -n-octyloxycarbonylaminophenyl) propane 12.2- (4′-hydroxyphenyl) -2- (4 ″ -n -Decyloxycarbonylaminophenyl) propane 13.2- (4'-hydroxyphenyl) -2- (4 "-n-dodecyloxycarbonylaminophenyl) propane 14.2- (4'-hydroxyphenyl) -2 -(4 "-n-tetradecyloxycarbonylaminophenyl) propane 15.2- (4'-hydroxyphenyl) -2- (4" -n-hexadecylcarbonylaminophenyl) propane 16.2- (4 '-Hydroxyphenyl) -2- (4 "-n-octadecylcarbonylaminophenyl) propane 17.2- (4'-hydro Xyphenyl) -2- (4 "-cyclopentyloxyoxycarbonylaminophenyl) propane 18.2- (4'-hydroxyphenyl) -2- (4" -cyclohexyloxyoxycarbonylaminophenyl) propane 19.2- (4 ' -Hydroxyphenyl) -2- [4 "-(2-tetrahydrofurfuryl) oxycarbonylaminophenyl] propane 20.2- (4'-hydroxyphenyl) -2- [4"-(2-methoxyethyl) oxycarbonyl Aminophenyl] propane 21.2- (4'-hydroxyphenyl) -2- [4 "-(2-ethoxyethyl) oxycarbonylaminophenyl] propane 22.2- (4'-hydroxyphenyl) -2- [4 "-(2'-phenoxyethyl) oxycarbonylaminophenyl Propane 23.2- (4'-hydroxyphenyl) -2- [4 "-(2'-phenoxyethoxyethyl) oxycarbonylaminophenyl] propane 24.2- (4'-hydroxyphenyl) -2- [4"- (2 '-(4-chlorophenoxy) ethyloxycarbinylaminophenyl] propane 25.2- (4'-hydroxyphenyl) -2- (4 "-allyloxycarbonylaminophenyl) propane

26.2- (4′-Hydroxyphenyl) -2- (4 ″ -benzyloxycarbonylaminophenyl) propane 27.2- (4′-Hydroxyphenyl) -2- (4 ″ -phenyloxyoxy Carbonylaminophenyl) propane 28.2- (4'-hydroxyphenyl) -2- [4 "-(1-naphthyl) oxycarbonylaminophenyl] propane 29.2- (4'-hydroxyphenyl) -2- [ 4 "-(2-naphthyl) oxycarbonylaminophenyl] propane 30.2- (4'-hydroxyphenyl) -2- [4"-(4-methylphenyl) oxycarbonylaminophenyl] propane 31.2- ( 4'-hydroxyphenyl) -2- [4 "-(4-methoxyphenyl) oxycarbonylaminophenyl] p Bread 32.2- (4'-hydroxyphenyl) -2- [4 "-(3-methoxyphenyl) oxycarbonylaminophenyl] propane 33.2- (4'-hydroxyphenyl) -2- [4"- (2-methoxyphenyl) oxycarbonylaminophenyl] propane 34.2- (4'-hydroxyphenyl) -2- [4 "-(4-phenoxyphenyl) oxycarbonylaminophenyl] propane 35.2- (4 '-Hydroxyphenyl) -2- [4 "-(4-fluorophenyl) oxycarbonylaminophenyl] propane 36.2- (4'-hydroxyphenyl) -2- [4"-(4-chlorophenyl) oxycarbonyl Aminophenyl] propane 37.2- (4′-hydroxyphenyl) -2- [4 ″-(3-chlorophenyl Oxycarbonylaminophenyl] propane 38.2- (4'-hydroxyphenyl) -2- [4 "-(4-nitrophenyl) oxycarbonylaminophenyl] propane 39.2- (4'-hydroxyphenyl) -2- [4 "-(4-acetylphenyl) oxycarbonylaminophenyl] propane 40.2- (4'-hydroxyphenyl) -2- [4"-(4-acetyloxyphenyl) oxycarbonylaminophenyl] propane

41.2- (4′-hydroxyphenyl) -2- [4 ″-(4-benzyloxyphenyl) oxycarbonylaminophenyl] propane 42.2- (4′-hydroxyphenyl) -2- [4 "-(4-cumylphenyl) oxycarbonylaminophenyl] propane 43.2- (3'-methyl-4'-hydroxyphenyl) -2- (4" -ethoxycarbonylaminophenyl] propane 44.2- (3 ' -Methyl-4'-hydroxyphenyl) -2- (4 "-benzyloxycarbonylaminophenyl] propane 45.2- (3 ', 5'-dimethyl-4'-hydroxyphenyl) -2- (4"- Phenyloxycarbonylaminophenyl] propane 46.2- (4'-hydroxyphenyl) -2- (3 "-methyl-4"- Phenyloxycarbonylaminophenyl] propane 47.1- (4'-hydroxyphenyl) -1- (4 "-phenyloxycarbonylaminophenyl] cyclohexane 48.1- (4'-hydroxyphenyl) -1- ( 4 "-methoxycarbaminophenyl] methane 49.2- (3'-hydroxyphenyl) -2- (4" -methoxycarbonylaminophenyl] propane 50.2- (3'-hydroxyphenyl) -2- (4 "-Cyclohexyloxycarbonylaminophenyl] propane 51.2- (3'-hydroxyphenyl) -2- (4" -allyloxycarbonylaminophenyl] propane 52.2- (3'-hydroxyphenyl) -2- (4 "-benzyloxycarbonylaminophenyl] propane 53.2- (3 ' Hydroxyphenyl) -2- (4 "-phenyloxycarbonylaminophenyl] propane 54.2- (3'-hydroxyphenyl) -2- [4"-(1-naphthyl) oxycarbonylaminophenyl] propane55. 2- (3'-hydroxyphenyl) -2- [4 "-(4-cyclohexylphenyl) oxycarbonylaminophenyl] propane

56.2- (3′-Hydroxyphenyl) -2- [4 ″-(4-chlorophenyl) oxycarbonylaminophenyl] propane 57.2- (3′-hydroxyphenyl) -2- (4 ″- Phenyloxycarbonylaminophenyl] cyclopentane 58.1- (2'-hydroxyphenyl) -1- (4 "-methoxycarbonylaminophenyl] methane 59.1- (2'-hydroxyphenyl) -1- (4" -Phenyloxycarbonylaminophenyl] methane 60.2- (2'-hydroxyphenyl) -2- (3 "-isopropoxycarbonylaminophenyl] propane 61.2- (2'-hydroxyphenyl) -2- ( 3 "-phenyloxycarbonylaminophenyl] propane 62.2- (4'-hydroxyphenyl ) -2- [3 "-(2-Naphthyl) oxycarbonylaminophenyl] propane 63.2- (4'-hydroxyphenyl) -2- [3"-(4-benzyloxyphenyl) oxycarbonylaminophenyl] Propane 64.1- (4'-hydroxyphenyl) -1- (3 "-methoxycarbonylaminophenyl] cyclohexane 65.2- (4'-hydroxyphenyl) -2- (3" -phenyloxycarbonylaminophenyl] Butane 66.1- (4'-hydroxyphenyl) -1- (2 "-benzyloxycarbonylaminophenyl] methane

According to the present invention, a compound represented by the general formula (1)
The compound is the same as the compound represented by the general formula (2)
Known by the compound represented by the general formula (3)
Method, for example, Methodode der Organischen
・ Chemie (MethodenDer Organischen Chemie)8
 , 13 7 (1952), etc.
Can be

[0015]

Embedded image (Wherein, R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₁ and R ₂ may form a ring, and R ₃ , R ₄ , R ₅ and R ₆ are hydrogen Represents an atom, a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group or a hydroxyl group, and R ₇ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group)

[0016]

Embedded image (Wherein, R ₈ represents an alkyl group, an alkenyl group, an aralkyl group or an aryl group)

In the reversible thermochromic material of the present invention, the color is selected according to the type of the electron-donating color former, and the color change temperature is determined according to the type of the electron-accepting compound and the type of the non-volatile hydrophobic compound having an arbitrary melting point. Further, by containing one or more compounds represented by the general formula (1), light resistance can be improved. These four-component reversible thermochromic material is used as it is as a coloring material, or
It is encapsulated in microcapsules and used in an apparently stable solid state that is more stable and easy to handle. The compound represented by the general formula (1) used in the present invention has good solubility in alcohols which are widely used among reversible thermochromic materials, and furthermore, the compound represented by the general formula (1) The reversible thermochromic material produced by using the above can encapsulate the composition, and the encapsulated material has improved light resistance, stable thermochromic properties, and clearly discolors at a predetermined temperature. Etc.

The component (a) of the present invention, that is, as a color former, a triphenylmethane compound, a fluoran compound, a phenothiazine compound, an indolylphthalide compound, a leucouramine compound, a spiropyran compound, a rhodamine lactam compound , Triphenylmethane compounds, azaphthalide compounds, benzoxazine compounds and the like. For example, crystal violet lactone [CVL], 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (p-dimethylamino) Phenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylamino) Phenyl) -3-
(1,2-dimethylindol-3-yl) phthalide,
3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide,

3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3
-Bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -6-dimethylaminophthalide,
3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-ethyl-2-methylindol-3-yl)
-4-azaphthalide, 3- (4-diethylamino-2-
Ethoxyphenyl) -3- (1-octyl-2-methylindol-3-yl) -4-azaphthalide, benzoylleucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-
Phenyl-spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho (6'-methoxybenzo) spiropyran, rhodamine-B-anilinolactam, 3-diethylamino-6methyl-7-chlorofluoran, 3 -Diethylamino-5,7-dimethylfluoran,

3-diethylamino-7-chlorofluoran, 3-diethylamino-7,8-benzfluoran,
3- (cyclohexylamino) -7-methylfluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-7-anilinofluoran, 3-diethylamino-7-dibenylaminofluor Oran, 3-diethylamino-7-o-chloroanilinofluoran, 3-dibutylamino-7-o-chloroanilinofluoran, 3- (N-ethyl-Np-toluidino) -6-methyl-7 -Anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3
-Dibutylamino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino)-
6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-diethylamino-7- (m- Trifluoromethylanilino) fluoran, 3- (N-ethyl-N-isoamylamino)-
6-methyl-7-anilinofluoran and the like.

The electron-accepting compound of the component (b) of the present invention includes phenolic substances, aromatic carboxylic acids or their esters and polyvalent metal salts, phosphoric acid esters and salts thereof, and 1,2,3-triazole. And its derivatives. For example, bisphenol A, 2,2-bis (4-
Hydroxyphenyl) pentane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane,
1-bis (4-hydroxyphenyl) hexane, 2,2
-Bis (4-hydroxyphenyl) propane, 1,1-
Bis (4-hydroxyphenyl) pentane, 1,1-
(4-hydroxyphenyl) hexane, 1,1-bis (4-hydroxyphenyl) heptane, 1,1-bis (4-hydroxyphenyl) octane, 1,1-bis (4-hydroxyphenyl) dodecane, 2, 4-bis (4-hydroxyphenyl) -4-methylpentane, 2
-(4-hydroxyphenyl) -2- (4-hydroxy-3-methylphenyl) propane, bis- (4-hydroxy-3,5-dimethylphenyl) sulfide, bis-
(4-hydroxyphenyl) sulfide,

Bis- (4-hydroxy-3,6-dimethylphenyl) sulfide, bis- (4-hydroxy-3)
-Methylphenyl) sulfide, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane,
Phenols such as 1,4-bis (4-hydroxyphenylthio) -3-oxapentane, benzyl p-hydroxybenzoate, methyl p-hydroxybenzoate, dimethyl 4-hydroxyphthalate, 5-di-
α-methylbenzylsalicylic acid, 3,5-di-tert
-Butylsalicylic acid, salicylic acids such as 3-α, α-dimethylsalicylic acid or polyvalent metal salts, ethyl acid phosphate, n-butyl acid phosphate, 2-ethylhexyl acid phosphate, lauryl acid phosphate, cetyl acid phosphate Acid phosphate compounds such as hete, stearyl acid phosphate, dimyristyl phosphate, dicetyl phosphate, distearyl phosphate, dibehenyl phosphate, and metal salts thereof.

The non-volatile hydrophobic compound having an arbitrary melting point, which is the component (c) of the present invention, includes alcohols, esters, ethers, ketones, carboxylic acids or acid amides. Are exemplified as follows. 1) Alcohols: monohydric alcohols, polyhydric alcohols and derivatives thereof, specifically n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, n-lauryl alcohol, n-myristyl alcohol, n -Cetyl alcohol, n-stearyl alcohol, n-icosyl alcohol, n-docosyl alcohol, n-mericyl alcohol, isocetyl alcohol,
Isostearyl alcohol, isodocosyl alcohol,
Oleyl alcohol, cyclohexanol, cyclopentanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, hexylene glycol, cyclohexane-1,4- Diol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, sorbit, mannitol and the like.

2) Esters: Specifically, amyl acetate, octyl acetate, butyl propionate, octyl propionate, phenyl propionate, ethyl caprylate,
Amyl caproate, ethyl caprylate, amyl caprylate, ethyl caprate, amyl caprate, octyl caprate, methyl laurate, ethyl laurate, butyl laurate, hexyl laurate, octyl laurate, dodecyl laurate, lauric acid Cetyl, stearyl laurate, methyl myristate, ethyl myristate, butyl myristate, hexyl myristate, octyl myristate, lauryl myristate, myristyl myristate, cetyl myristate, stearyl myristate, methyl palmitate, methyl palmitate, ethyl palmitate, Butyl palmitate, hexyl palmitate, octyl palmitate, lauryl palmitate, myristyl palmitate, cetyl palmitate, stearyl palmitate, methyl stearate , Ethyl stearate, butyl stearate, hexyl stearate, octyl stearate, lauryl stearate, myristyl stearate, cetyl stearate, stearyl stearate, methyl behenate, ethyl behenate, propyl behenate, butyl behenate, Ethyl benzoate, butyl benzoate, amyl benzoate, phenyl benzoate, ethyl acetoacetate, methyl oleate, butyl oleate, butyl acrylate, diethyl oxalate, dibutyl oxalate, diethyl malonate, diethyl malonate, dibutyl malonate Dibutyl tartrate, dimethyl sebacate, dibutyl sebacate, dimel phthalate, dible phthalate, dioctyl phthalate, dibutyl fumarate, diethyl maleate, triethyl citrate, 12-hydroxystelate Triglyceride aricate, castor oil, methyl 12-hydroxystearate, methyl dioxystearate and the like.

3) Ethers: specifically, diethylene glycol dimethyl ether, diphenyl ether, distearyl ether, butyl ether, hexyl ether, diisopropyl benzyl ether, dioxane, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, ethylene glycol diethyl ether, ethylene glycol diphenyl ether And ethylene glycol monophenyl ether. 4) Ketones: specifically, diphenyl ketone, distyryl ketone, diethyl ketone, ethyl butyl ketone, methylhexyl ketone, mesityl oxide, cyclohexanone, propiophenone, benzophenone, 2,4-pentanedione, acetonylacetone , Diacetone alcohol, ketone wax and the like.

5) Carboxylic acids: specifically, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotinic acid, partulic acid, Oleic acid, ricinoleic acid, linoleic acid, linolenic acid, eleostearic acid, erucic acid and the like. 6) Acid amides: specifically, caprylic amide, capric amide, lauric amide, myristic amide, palmitic amide, stearic amide, behenic amide, oleic amide, benzamide and the like. The above compounds may be used alone or in combination of two or more to obtain an arbitrary melting point.

The amount of each component used in the reversible thermochromic material of the present invention is as follows: (a) color former: (b) electron-accepting compound: (c) non-volatile hydrophobic material having an arbitrary melting point. Compound = 1: preferably in the range of 0.1 to 50:10 to 100, and (d) 0.5 to 50 parts by weight of the compound represented by the general formula (1) with respect to 100 parts by weight of the total of the above three components. Preferably it is in the range of 1 to 20 parts by weight. The reversible thermochromic material of the present invention, in addition to the above components, a dye having no color change within a range that does not impair the performance of the color change, a pigment, an antioxidant, an antioxidant, an ultraviolet absorber and the like as necessary. Can be used together.

The reversible thermochromic material of the present invention comprises (a) a color former, (b) an electron-accepting compound, (c) a nonvolatile hydrophobic compound having an arbitrary melting point, and (d) a compound represented by the general formula (1) ) Can be prepared as a component. However, the reversible thermochromic material composed of the above components is chemically active and is easily affected by the external environment. For this reason, reversible thermochromic materials have been developed to protect the original functions and to enable the use of several types of hues and discoloration temperatures under the same conditions, and to increase the utilization for various applications. A method of encapsulating in a microcapsule wall membrane is used.

The microcapsules containing the reversible thermochromic material used in the present invention are produced by a known method.
For example, it is produced by a coacervation method using gelatin, an interfacial polymerization method, an In-Situ polymerization method, a submerged curing method, or the like. The microcapsules containing the reversible thermochromic material may be used as they are as an aqueous ink or an aqueous paint, or may be used after being powdered by filtration, filtration by centrifugation and drying. The powdered microcapsules are melted in a resin to form a film,
Processed into pellets, filaments, etc., adhered to fibers, printed again on paper, film, pottery, glass, fibers, etc. using oil-based ink by silk screen, gravure, offset, flexo, etc. Temperature detection, display devices and the like.

[0030]

EXAMPLES The method of the present invention will be described in detail with reference to examples, but the present invention is not limited thereto. Example 1 The following components (a), (b), (c) and (d) were mixed and dissolved by heating to form an internal phase. Using the internal phase thus obtained, microcapsules were produced by the following method. Component (a): 2.5 g of CVL Component (b): 2.5 g of bisphenol A Component (c): 44.0 g of cetyl alcohol Component (d): Compound 1.0 g of Exemplified Compound No. 2 ethylene-anhydride Maleic acid polymer (Monsanto "EMA-
31 ”), 25 g of a 10% by weight aqueous solution and 60 g of water are mixed,
After adjusting the pH to 4.0 with 10% by weight of NaOH, the temperature was maintained at 60 ° C., and 50 g of the internal phase was emulsified with a homomixer. Then, a methylated methylolmelamine aqueous solution having a solid content of 80% by weight (Mitsui Toatsu Chemical, 15 g of “Euramine T3”), and kept at 70 ° C. for 2 hours with stirring to obtain an average particle size of 10 μ
m was obtained. To 50 g of this microcapsule solution, 10% by weight of polyvinyl alcohol (Kuraray "117") was added, mixed and stirred, then coated and dried on woodfree paper so that the dry coating amount was 8 g / m ^2, and reversible thermochromic A material sheet was obtained. The color density of this reversible thermochromic material sheet was measured with a Macbeth densitometer. Higher numbers indicate higher concentrations. Further, the reversible thermochromic material sheet is transferred to a carbon arc fedometer (Suga Test Machine).
After exposure for a time, the density after the test was measured using a Macbeth densitometer, and the sheets before the test were compared. The larger the value and the smaller the difference from before the test, the less the fading due to light. The results are shown in Table 1 (Table 1).

Examples 2 to 17 In place of the four components of Example 1, components (a), (b), (c) and (d) shown in Table 1 were used and mixed in the same manner as in Example 1. , Heated and dissolved to prepare an internal phase. Using the obtained internal phase, microcapsules were produced by the microencapsulation method described above. A reversible thermochromic material sheet was obtained in the same manner as in Example 1 using the obtained microcapsule liquid. The concentration of the reversible thermochromic material sheet was measured, and a light fastness test was performed. The results are shown in Table 1.

Comparative Example 1 A reversible thermochromic material sheet was prepared and tested in the same manner as in Example 1 without adding the component (d). The results are shown in Table 1. Comparative Example 2 A reversible thermochromic material sheet was prepared and tested in the same manner as in Example 3 without adding the component (d). The results are shown in Table 1. Comparative Example 3 A reversible thermochromic material sheet was prepared and tested in the same manner as in Example 6 without adding the component (d). The results are shown in Table 1. Comparative Example 4 A reversible thermochromic material sheet was prepared and tested in the same manner as in Example 9 without adding the component (d). The results are shown in Table 1. Comparative Example 5 A reversible thermochromic material sheet was prepared and tested in the same manner as in Example 11 without adding the component (d). The results are shown in Table 1.

[0033]

[Table 1] CLV: Crystal violet lactone, phthalide-based compound manufactured by Yamamoto Kasei Co., Ltd. Blue-63: Phthalide-based compound manufactured by Yamamoto Kasei Co., Ltd. Red-3: Fluoran-based compound manufactured by Yamamoto Kasei Co., Ltd. Green DCF: manufactured by Hodogaya Chemical Co., Ltd. Fluorane-based compound Black-15: Fluorane-based compound manufactured by Yamamoto Kasei Co., Ltd. Indolyl Red: Phthalide-based compound manufactured by Yamamoto Kasei Co., Ltd. PSD-184: Fluorane-based compound manufactured by Nippon Soda Co., Ltd. BHMS: Bis (4-hydroxy-) 3-methylphenyl) sulfide

As apparent from Table 1, (a) a color former,
The present invention wherein component (d) is further added to (b) an electron-accepting compound, (c) a compound selected from alcohols, esters, ethers, ketones, carboxylic acids or acid amides to form microcapsules. The reversible thermochromic material of
The light fastness is clearly superior to the unadded one.

[0035]

According to the present invention, it has become possible to obtain a reversible thermochromic material which has a fast response to changes due to heat and has remarkably improved light fastness.

Continuation of the front page (72) Inventor Masakatsu Nakatsuka 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Examiner, Mitsui Toatsu Chemicals Co., Ltd. Yoko Watanabe (56) References JP-A-5-306373 (JP, A) JP-A Sho 49-10180 (JP, A) JP-A-50-75992 (JP, A) JP-A-53-102284 (JP, A) JP-A-57-65772 (JP, A) JP-A-57-167380 (JP, A) A) JP-A-1-165688 (JP, A) JP-A-2-255332 (JP, A) JP-A-2-70484 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) C09K 9/02 G01K 11/12 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A reversible thermochromic material comprising (a) an electron-donating color former, (b) an electron-accepting compound, and (c) a nonvolatile hydrophobic compound having an arbitrary melting point, further comprising (d) A reversible thermochromic material comprising at least one compound represented by the general formula (1) (formula 1). Embedded image (Wherein R ₁ and R ₂ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R ₁ and R ₂ may form a ring; R ₃ , R ₄ , R ₅ , R ₆ are a hydrogen atom, a chlorine atom, a chain alkyl group having 1 to 8 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, a hydroxyl group, and R ₇ is a hydrogen atom or a chain alkyl group having 1 to 4 carbon atoms. , R ₈ is a hydrogen atom,
A chain alkyl group having 1 to 20 carbon atoms, a cyclic alkyl group having 5 to 7 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, and 7 carbon atoms
~ 20 aralkyl, phenyl, naphthyl, and heteroaromatic groups) 2. The reversible material according to claim 1, wherein the nonvolatile hydrophobic compound having an arbitrary melting point is at least one selected from alcohols, esters, ethers, ketones, carboxylic acids and acid amides. Thermochromic material. 3. An electron-donating color former, (b) an electron-accepting compound, (c) a non-volatile hydrophobic compound having an arbitrary melting point, and (d) a compound represented by the general formula (1). The reversible thermochromic material according to claim 1 or 2, wherein a component comprising the following is encapsulated in the microcapsule wall film.