JPS6268881A - Thermally reversely desensitizing composition - Google Patents

Abstract

PURPOSE:A novel, practical thermally reversely desensitizing composition, comprising four components of an electron donative coloring dyestuff, an electron acceptor developer, a first desensitizing agent and a second desensitizing agent. CONSTITUTION:The aimed thermally reversely desensitizing composition comprising (A) 0.1-20wt% electron donative coloring dyestuff, (B) 0.1-40wt% electron acceptor developer, (C) 0.5-20wt% azomethine or carboxylic acid primary amine salt as a first desentizing agent and (B) 1-50wt% alcohol, amide or ester as a second desensitizing agent. A weight ratio of the component A:B is preferably 1:1-1:5 and a weight ratio of the component C:D is preferably 1:2-1:20.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has extremely wide industrial applicability.
This invention relates to a novel and practical heat reverse desensitization composition.

[Prior Art] As is known in the art, there are certain substances that are colorless at a certain temperature, but develop color when an appropriate temperature is applied, making it possible to recognize the color, or substances that are colored at room temperature but reach high temperatures. Printing inks and paints are prepared using specific substances that erase or change color, that is, exhibit thermochromism, and are used in various applications requiring temperature-sensitive displays.

Such specific substances or analogues that exhibit the above effects include those that first release moisture and change color when heated, and then absorb moisture again and restore color when cooled, and those with transition metal salts such as cobalt, nickel, and manganese. There are double salts with aminic amides such as xamethylenetetramine, as well as mercury iodide, complex salts of mercury iodide and other metal iodides, heavy metal compounds such as lead chromate, ammonium metavanadate, etc., and dixanetylene. , organic compounds such as bianceron, and some organic dyes and pigments.

However, the above-mentioned compound groups have any of the following drawbacks, and all have extremely low adaptability.

(1) Significant toxicity.

(2) Acts only in the presence of moisture.

(3) There is no optional selection of color change temperature and color.

(4) Discoloration to a similar hue and unclear.

Furthermore, as the substance exhibiting the thermochromism phenomenon,
Cholesteric liquid crystals or mixtures of cholesteric liquid crystals and nematic liquid crystals are available, but their applications are severely limited due to poor color density, lack of arbitrariness in color and color change temperature, and extremely high prices. It has the disadvantage of being

By the way, in recent years, color developers that use normally colorless electron-donating color-forming pigments as color components and cause coloration by accepting the electrons, such as attapulgide, kaolin clay, and zinc chloride, have been developed.

The coloring system of temperature-sensitive copying and pressure-sensitive copying based on the binding color reaction of electron acceptors such as phenols, zinc salicylate, aluminum benzoate, etc. is repurposed, and in addition to these constituents, various solvents, i.e. , alcohols, esters, ketones, acid amides, etc., which exhibit a so-called desensitizing effect (discoloration phenomenon), are allowed to coexist, and color development and discoloration are reversibly caused by appropriate external temperature changes. Compositions are known.

”The advantage of the dual composition is that the electron-donating color pigments are
Many different hues are already known and can be selected arbitrarily, and since all solvents including water are desensitizers, the discoloration temperature can be arbitrarily set over a wide range from low to high temperatures depending on the type of solvent. It is at the point of Uru etc.

However, the above composition has the following drawbacks.

That is, the solvents have to be used in significantly larger amounts to achieve the desired thermochromic effect;
It has significant weaknesses in color density limitations and durability, especially in terms of durability against solvents, washing, and heat. If the amount of solvents is reduced, it is difficult to reduce the desensitizing effect, that is, completely colorless, and there arises the problem that an undesirable residual color may be present, or the desensitizing effect may no longer be exhibited at all.

[Problems to be Solved by the Invention] As a result of various studies on the conventional problems, the present inventors have newly developed azomethines or carboxylic acid primary amine salts which are weakly basic and poorly soluble substances. The present invention was completed based on the new knowledge that by using it in combination with conventional solvents, it is possible to completely eliminate the drawbacks of the conventional products mentioned above and obtain a new thermochromic material with extremely excellent performance. It is.

Measures to solve problem E] Next, the configuration of the present invention will be described.

The present invention provides electron-donating coloring dyes, electron-accepting color developers,
It is characterized by the coexistence of four components: azomethines or carboxylic acid primary amine salts as a first desensitizer, and alcohols, amides, or esters as a second desensitizer. It is a thermoreversible desensitizing composition.

[Example] Electron-donating color pigments as color components of the present invention include:
3-3゛dimethoxyfluorane (yellow), 3-chlor.6-phenylaminofluorane (yellow-orange), 3-diethylamino.
6-methyl 7-chlorofluorane (vermilion), 3-diethyl 7-
8 pentfluorane (peach), crystal violet lactone (3.3°3°° tris(P dimethylaminophenyl) phthalide) (purple blue), malachite green lactone (3.3'bis(P dimethylaminophenyl) phthalide) ( Examples include substituted phenylmethane and fluorans such as 3-diethylamino-6-methyl-7-phenylaminofluoran (black) N!i, various indolylphthalides, spiropyran, coumarins, etc. , one or more of these may be used in combination. In this case, it is desirable that the electron-donating coloring pigments account for 0.1 to 20% of the total composition.

Next, in the present invention, examples of electron-accepting color developers (including proton-donating) that make such dyes dark red include phthalate,
Benzoic acid, terephthalic acid, pyromellitic acid, trimellitic acid, toluic acid.

Carboxylic acids such as oxystearin, oxalic acid, lauric acid, stearic acid, tartaric acid, citric acid, anthranilic acid, etc., and their ammonium salts or metal salts, phenol, phenylphenol, β-naphthol, resorcin, prologlycine, pytroquinone, dihydroxy Phenols and their salts such as naphthalene, bisphenol S, phenolphthalene, phenolic resin oligomers, salicylic acid, oxybenzoic acid, ethyl oxybenzoate, salomethyl, resorcinic acid, methylenebissalicylic acid, salicylic acid amide, methyl β-oxynaphthoate oxycarboxylic acids and their salts, as well as various thiophenols and their derivatives, triazoles, tetrasols, mercapto group-containing heterocyclic compounds, thiourea derivatives, phosphoric acid esters, sulfonated products, and zinc chloride.

Examples include inorganic compounds such as tin chloride and oxyantimony salts, and in the present invention, one or more of these -1- is used.

In addition, the electron-accepting color developer (proton donor) in 1- is as follows:
In the case of the present invention, it is 0.1 to 40% by weight of the total composition,
-1 In view of the relationship with the above-mentioned electromagnetic coloring pigments, it is preferable that the amount is the same to about 5 times as much.

Next, referring to the first desensitizer that constitutes the third component of the present invention and exhibits the greatest feature of the present invention, first of all, one of them, alametins, is as follows: They are represented by formulas (1) to (3), and can be easily obtained by mixing aldehydes and amines corresponding to the desired structure and dehydrating the mixture.

R-CH=N-R'・・・・・・・・・Self・・・・・・
・(1) R-CH=N-R' -N-CH-R...(
2) RN=HC-R' -CH=NR...(3)
(In the above formula, R and R' represent an aliphatic residue, a substituted aliphatic residue, an aromatic residue, a substituted aromatic residue, a heterocyclic residue, or a substituted amino group, and each The formula shall include at least one of an aromatic residue or a substituted aromatic residue.) Incidentally, if the above aldehydes and amines are listed, first among the aldehydes, aromatic aldehydes include: Benzaldehyde, tolualdehyde, anisaldehyde, cyanaldehyde, chloraldehyde, cuminaldehyde, phenylacetaldehyde, heliotrobin,
Examples of aliphatic aldehydes include acetaldehyde, butyraldehyde, hexylaldehyde, palmitylaldehyde, and stearylaldehyde. Examples of dialdehydes include glutaraldehyde, azifaldehyde, and terephthalaldehyde. Examples include humans, cryoxal, and the like.

On the other hand, among the amines that react with these aldehydes, aromatic amines include aniline, toluidine, cresidine, anisidine, naphthylamine, chloroaniline, butylaniline, cyclohexylamine, etc., and aliphatic amines include ethylamine, Butylamine, laurylamine, myristylamine, palmitylamine,
stearylamine, benzylamine.

Examples of diamines include cinnamylamine, ethylene diamine, stearylpropylene diamine, phenylene diamine, 1.6 diamine hexane, 1.
Examples include 8-diaminooctane and benzidine, and further heterocyclic amines include aminopyridine and aminoquinoline.

The carboxylic acid primary amine salt, which is another first desensitizer in the present invention, is represented by the following formula (4) and can be easily obtained by reacting carboxylic acids and primary amines. However, the salts are preferably poorly soluble in water.

R-(COOH le R'-(NH full...(4)(
(wherein,
Myristic acid, stearic acid, palmitic acid, linoleic acid, lylunic acid.

Examples of aromatic carboxylic acids include oleic acid, behenic acid, enanthate, sebacic acid, and azelaic acid.
Bensikoic acid, P-chlorobenzoic acid, P-butylbenzoic acid, 1-naphthalene carboxylic acid, cinnamic acid, phenyl acetic acid,
Methacrylic acid, terephthalic acid, 2furancarboxylic acid, 2
Examples include benzofurancarboxylic acid and cinchoninic acid.

On the other hand, if the primary amines that react with these carboxylic acids are listed, the aliphatic primary amines include caprylamine, laurylamine, myristylamine, stearylamine, coconut amine, oleic amine, hexamethylene diamine, etc. Examples of aromatic amines include butylaniline, chloroaniline, aniline, naphthylamine, phenylenediamine, dichlorobenzidine, aminothiazole, aminopyridine, and the like.

The above-mentioned first desensitizer is preferably 0.5 to 20% by weight based on the total composition, and the weight ratio with the below-mentioned second desensitizer is preferably 1:2 to 20.

Next, regarding the solvents constituting the fourth component of the present invention, the alcohols include octyl alcohol, nonyl alcohol, decyl alcohol, dodecyl alcohol, tetradecyl alcohol, cetyl alcohol,
Examples include saturated alcohols such as octadecyl alcohol, ceryl alcohol, myricyl alcohol, and unsaturated alcohols such as geraniol, nerol, linalool, oleyl alcohol, and the like.

Amides include acetamide, caprylic acid amide, lauric acid amide, myristic acid amide, stearic acid amide, oxystearic acid amide, bisstearic acid amide, acetoacetylamide, acetanilide, valatoluenesulfoamide, and benzoic acid. amide, salicylic acid amide, oxalic acid amide, phthalic acid amide, phthalimide, diethyl urea, thiourea, diphenyl urea, benzimidazole and the like.

Examples of the esters include stearic acid glyceride, lanolin, diphenyl phthalate, lauric acid glyceride, propyl laurate, palmitylic acid glyceride, and the like. In this case, the amount of the solvent is desirably 1 to 50% by weight based on the total composition.

-121 In the present invention, the solvents include the alcohols mentioned above,
The reason why the solvents are limited to amides or esters is that these solvents have melting points and softening points that can be systematically obtained compared to other solvents.

By the way, both of the above-mentioned desensitizers have the property that the higher the temperature and the higher the melting point or freezing point, the more discoloration occurs at high temperatures, and the lower the desensitizers are, the more effective they are at lower temperatures.

Thus, the thermochromic temperature range of the present invention is as follows.

It is possible to set various desired temperatures ranging from about -40° C. to about 150° C., and a significant color change is observed after the set temperature, and thus the temperature-sensitive color change is reversibly repeated.

Table 19 and Table 2 below are examples of the first desensitizer used in the present invention, and Table 31, Table 4 and Table 5 are examples of the second desensitizer used in the present invention, and each of these tables The decoloring temperature in the table indicates the temperature at which desensitization starts, and above this temperature, the color disappears.

As for the combination of the first and second desensitizers of the present invention, alcohols or esters are generally preferred for azomethines, and amides are preferred for carboxylic acid primary amine salts.

Table 1 Table 2 Table 3 Table 4 Table 5-15 The four-double component in the present invention is used as a mixed solution, emulsion dispersion, capsule encapsulation, or the like. The encapsulation method and membrane material are not particularly limited,
In addition, various drugs, such as surfactants, may be added to these coexistence systems or the medium containing the coexistence systems, if necessary.

Drying regulators, antifoaming agents, resins, cross-linking materials, and binders.

Viscosity modifiers, dyes, pigments, optical brighteners, ultraviolet absorbers,
UV stabilizer, infrared absorber 1 extender pigment 9 foaming agent, water repellent, metal powder, glass bulb, plastic sphere, antioxidant,
It does not depart from the gist of the present invention even if a reduction inhibitor, an electrolyte, a reducing agent, an oxidizing agent, an acid alkali, a preservative, a chelating agent, a dyeing carrier, an oil or fat, a fragrance, etc. are appropriately added.

When using the thermoreversible desensitizing composition of the present invention.

For example, in the case of printing, the composition is dissolved, emulsified or incorporated into the ink vehicle, followed by gravure, offset.

It may be applied to the printing material by a known printing method such as flexography or spraying with a screen spray gun, and then dried or heated if necessary.

Treatment with UV irradiation, infrared irradiation, etc. In this way, any thermoreversible discoloration pattern can be displayed on paper 1 synthetic resin film, glass, ceramics, leather, metal, etc. Similarly, in printing, transfer printing, and painting, the printing ink vehicle It can be displayed on fabrics and other materials through a treatment similar to that used in compounding.

On the other hand, it is also possible to optionally blend the composition of the present invention into waxes, synthetic resins, soap, etc., or to obtain thermoreversibly desensitized molded products by using the composition in combination with the above-mentioned printing film.

Incidentally, products using the thermoreversible desensitizing composition according to the present invention include direct printing, knife coating or Transfer prints, beach poles, floats, buckets.

Cups, bath stirring rods, etc., printed on synthetic resin films, foam molded objects (sponge and foam), etc., and molded onto the base material at the same time, soaps, doll hair, various molded toys, etc. As in, waxes 1 synthetic resin,
Examples include those kneaded and molded into fiber materials, and those coated with painted cloth as a base material, or cut and sewn, such as stuffed animals, animal toys, clothing, and artificial flowers.

Next, the discoloration temperature ranges of various specific examples and control examples of the compositions of the present invention are shown in Tables 6-1 to 6-3.

In addition, in the table, the first component, second component, third component, and fourth component are electron-donating coloring dyes, electron-accepting color developer, first desensitizer, and second desensitizer, respectively. Same as shown below)
Crystal violet lactone and bisphenol A were used as the first and second components, respectively. The numbers in parentheses indicate the weight percent of each component. In the table, those lacking the third component are comparative examples, and all the examples are examples of the present invention.

Table 6-1 Table 6-2 -20 = Table 6-3 According to Tables 6-1 to 6-3 above, when the first desensitizer is used in combination with the composition of the present invention, the dye concentration increases and desensitization occurs. It can be clearly seen that the temperature range (blue → colorless) is significantly narrowed and the sensitivity is significantly improved.

Further, the correlation between the coloring rate and temperature of the inventive examples and comparative examples having the compositions shown in Table 7 below is shown in the drawings. The drawing clearly shows the effect of the first desensitizer in the composition of the present invention.

Table 7 Next, specific examples of the present invention will be shown.

Example 1 Glassine paper with silicone treatment on one side (98g/ml
) was coated with Niracera PE154 (trade name, acrylic acid ester resin) on the entire surface with a roll coater to a thickness of 85 mm, and after air drying, coated with mirror coated paper (100 mm).
g/m2) to create a tack seal base sheet. On the mirror-coated paper of the sheet, 1 part by weight of crystal violet lactone (hereinafter, parts by weight is abbreviated as parts), 2 parts of bisphenol A, 2 parts of P-methoxybenzylidene laurylamine, 12 parts of lauryl alcohol, and 5 parts by weight of crystal violet lactone.
A printing ink consisting of 87% ethyl cellulose/ethyl alcohol solution was printed on a one-point manga style animal screen type (100 mesh), dried, and after removing the solvent, a 200% polypropylene film was attached to the printed surface. A tack seal was obtained by laminating under heat. The seal was colorless at a temperature of 3° C. or higher, and a dark blue-purple animal net appeared at a temperature of -2° C. or lower, and could be reversibly repeated several times. As a comparative example, a tack seal was obtained in the same manner using only 20 parts of lauryl alcohol without using the P-methoxybenzylidene laurylamine in this example. The sharpness of the color change was also far inferior.

Example 2 Malachite green lactone 5 parts, tolyltriazole 10 parts, Pcumylbenzylidene P anisidine 15 parts, cetyl alcohol 60 parts, Tinuvin P (trade name, ultraviolet absorber) 3 parts, Epicote 828 (trade name, epoxy resin) A homogeneous hot solution of Ebicure T (product name: , curing agent) and 85°C.
After heating for 3 hours at
108 parts of spherical particles exhibiting a dark green color were obtained. 15 parts of the spherical particles, 2 parts of Groyer, Rho MF2G (trade name, fluorescent pigment), 8 parts of acrylic acid ester emulsion copolymer (solid content 33%) were mixed into 75 parts of an oil-in-water emulsion containing 1% methyl cellulose. The mixture was mixed to obtain a printing paste. Using the printing paste, a polka dot pattern was printed on a towel cloth using a screen type (80 meshes), and after drying, a dry heat treatment was performed at 110° C. for 3 minutes. When the thus obtained towel-printed cloth with a green polka dot pattern is soaked in hot water at 35°C,
It instantly changes to a yellow polka dot pattern, and the temperature of the hot water is 30 degrees.
When the temperature was lowered to below ℃, the pattern was restored to a green polka dot pattern. Moreover, this temperature-sensitive color change was reversibly repeated any number of times.

The general color fastness of the towel-printed fabric was generally grade 4 or higher, and it had sufficient durability. As a comparative example, if the green particles were printed in the same manner as the ester without using P Kumi Jl and benzylidene P anisidine in this example and using only 100 parts of cetyl alcohol, the reversible color change property was good, but , the color change temperature range is not sharp,
In order for the towel fabric, which had a yellow polka dot pattern in hot water, to turn green again, it was necessary to soak it in cold water below 25°C. The concentration was also poor.

Example 3 2 parts of 3-diethylamine/6-methyl/7-chlorofluoran, 2 parts of 1,2,3-benzotriazole, 2 parts of bisphenol F, 6 parts of benzylidene stearylamine, 24 parts of stearyl laurate, RIGOLAC 2004WM-2 (
Product name.

10 parts of unsaturated polyester (unsaturated polyester) were previously heated and dissolved, and this was poured into 200 parts of a 6% gelatin aqueous solution under stirring, and the stirring speed was adjusted to disperse it in the form of oil droplets with an average particle size of 20%. % benzoyl peroxide and 0.15 parts of cobalt naphthenate were added, and the mixture was heated and stirred at 80°C for 10 hours, and the microcapsule particles formed were separated by filtration, washed with water, and dried to obtain 39 parts of vermilion spherical particles. Obtained. 39 parts of the spherical particles were mixed and stirred with 1.5 parts of Demol N (trade name 9 dispersant) in 150 parts of water, and 2 parts of Sumitex resin 5ol (trade name, urea/melamine-formaldehyde initial combination) were added. Then add 0.1 part of Sumitex Accelerator MX (trade name, curing catalyst),
The reaction was carried out at 80°C for 3 hours. Thereafter, it was filtered and dried to obtain 39.5 parts of microcapsule particles with an average particle size of 20.

Next, 20 parts of the microcapsule particles were added to Nidocell #100.
Part 5, f! ! A printing ink was prepared by mixing 10 parts of a bi/ethylene copolymer resin and 65 parts of Kijiroll. With this printing ink, animal silhouette pattern gravure version (801X I
Polypropylene transparent film (
0.85 mm) and dried. Next, the non-printing surface of the film is electrostatically adhered to the container (inner surface of the molding mold), and Noblen Y-100 (trade name, polypropylene resin powder) is injected under pressure and heat to integrally mold the film. I got something. Thus, colorless above 18℃, 13℃
A vermilion-colored polypropylene container containing an animal silhouette was obtained. As a comparative example, microcapsule particles exhibiting a vermilion color were obtained using only 40 parts of stearyl laurate without using the benzylidene stearylamine of this example, and then molded products were formed through film printing. , the density is low, the color change temperature range is not sharp, and it does not become colorless unless the temperature reaches 23℃ or higher.
Moreover, it did not turn completely vermilion unless it was cooled to 10° C. or lower.

Example 4 5 parts of the vermilion microcapsule particles obtained in Example 3 were quickly kneaded into 95 parts of Sumirikisen G307 (trade name, polyethylene resin pellets) which can be melted at 110°C in advance, and then kneaded to a thickness of 0. It was molded into a 2 mm sheet and then cooled. Thus, it is colorless at temperatures above 18°C and turns vermilion at temperatures below 13°C. A polyethylene sheet which is extremely sensitive to temperature was obtained. Note that the sheet repeatedly underwent reversible temperature-sensitive discoloration no matter how many times = 28-.

Example 5 Glassine paper treated with silicone mold release agent (65g/m)
) on top of 0.2 parts of crystal violet lactone, 0.4 parts of bisphenol A, 0.6 parts of Pcumylbenzylidene, P anisidine, 2.4 parts of cetyl alcohol, and Tinuvin P.
(Product name, ultraviolet absorber) 0.1 part, FZ5037 (
Product name, fluorescent pigment) ethyl alcohol 10 parts and 10%
S-LEC BM-2 (product name, polybutyral resin)/
Using a printing ink consisting of 86 parts of ethyl alcohol solution, a one-point manga style figure and a pattern consisting of inverted characters are screen printed (100 meshes), and then Heiron powder (product name, polyester resin) is applied onto the pattern.
was sprayed and air-dried to obtain a thermal transfer sheet.

Next, the transfer sheet was brought into contact with a cotton knit T-shirt, and heat treatment was performed at 150° C. for 10 seconds using a hot press machine, and the base sheet was peeled off. In this way, a transfer printing pattern consisting of a one-point manga-like character pattern and letters appeared on the T-shirt.

When the color change temperature of the transfer printing pattern was actually measured, it was pink at temperatures above 35°C and purple at temperatures below 30°C, indicating that it was extremely sensitive to temperature changes. In addition, the general color fastness was generally grade 4 or higher, and the texture was also soft. As a comparative example, when Pcumylbenzylidene P aningin in this example was not used, the color did not become completely clear pink even at 35°C, but instead became a slightly bluish pink, and furthermore, at 30°C
Now, in order to get the perfect purple color, please use 2.
It was necessary to cool it to below 5°C.

Example 6 1 part of 3-diethyl 7.8-benzofluorane, 2 parts of 5(6) chlorine 1/1.2-3 penztriazol, 8 parts of stearylamine oleate, 30 parts of oleylamide, Coronate T 100' (commercial product) name, polyvalent isocyanate)
10 parts were heated and dissolved in advance, and this was added to 200 parts of Fuji Chemi HECK-150 (trade name, hydroxyethyl cellulose) 5% aqueous solution with stirring, and the stirring speed was adjusted to form oil droplets with an average particle size of 25 colors. form a dispersion. Next, 20 parts of Niraporan 1066 (trade name, polyol) was gradually added dropwise and reacted at 45 to 55°C for 8 hours. The microcapsule particles thus generated are separated from cancer using screen gauze and washed with water.

It was air-dried to obtain 56.8 parts of pink microcapsule particles. Five parts of the microcapsule particles were kneaded with 95 parts of a crushed soap base containing a fragrance, and then optionally shaped into an animal shape to obtain a cosmetic soap for children. The soap takes on a pink color at room temperature below 30° C., and can be repeated any number of times. As a comparative example, pink microcapsule particles were obtained using 50 parts of oleylamide without using the stearylamine oleate in this example, and the same cosmetic soap was made. However, it did not become colorless in hot water of 35°C, and it was necessary to immerse it in hot water of 45°C or higher to make it colorless. Also, the concentration was inferior to that of this example.

-31 Example 7 Colorless polyether type polyurethane foam (diameter 6cm)
60 parts of Pondic 1310F (trade name, water-dispersed polyurethane resin), Matsumin White) R-
2 (trade name, White 114), 2 parts of Mummmin Fixer F (trade name, urethane crosslinking agent), and 28 parts of water, and then dried, leaving a white urethane resin on the surface of the urethane foam. Form a film. Then, the white spherical material whose surface was covered with urethane resin was treated with Pondic 1310F (trade name, water-dispersed polyurethane resin).
60 parts, Glow Yellow MF2G (trade name, fluorescent pigment) 1 part, pink microcapsule particles obtained in Example 6 5
After soaking in a dispersion of 2 parts of Matsumin Fixer F (trade name, urethane crosslinking agent) and 32 parts of water, it was dried and then subjected to dry heat treatment at 140°C for 3 minutes to form a urethane foam surface. A 6 cm diameter pole coated with a resin film was obtained. The pole exhibited a red color at a room temperature of 30° C. or lower, and turned poor in color when exposed to a room temperature of 35° C. or higher or in hot water. The change can be reversibly repeated any number of times.

Example 8 A paste in which 2 parts of the pink capsule particles obtained in Example 6 were dispersed in 98 parts of Alphasol K (trade name, vinyl chloride resin for slush molding) was put into a mold for slush molding in the shape of an animal. The paste is poured into the mold, preheated at 180°C for 1 to 2 minutes to fill it up, the unhardened paste inside the mold is discharged, and then heated and cured at 200°C for 2 minutes. After cooling, the contents were taken out of the mold to obtain an animal-shaped slush molded product. The molded article was colorless at temperatures above 35°C and pink at temperatures below 30°C, and these changes could be repeated reversibly any number of times.

L Effects of the Invention J (1) Amines common to azomethines as the first desensitizer and carboxylic acid primary amine salts in the composition of the present invention, aldehydes as raw materials for the former, carboxylic acids, etc. constituting the latter There are many types of both. Therefore, the first desensitizers that can be obtained from these methods are extremely diverse, and there is an advantage in that they can be arbitrarily selected in consideration of the required performance, such as melting point, boiling point, etc.

(2) Since all of the first desensitizers in the composition of the present invention are weakly basic or those that dissociate bases at high temperatures, their desensitizing function is significant even with a small amount. In addition, the amines contained have the ability to prevent oxidation and contribute to improving the durability of colors.

(3) Since the first desensitizer in the composition of the present invention is used in combination with conventional desensitizing solvents, the amount of the solvents used is significantly reduced, resulting in a marked improvement in color density.

(4) By using the first desensitizer and the second desensitizer in combination, the disadvantage that the first desensitizer is somewhat unstable is compensated for, thereby producing a synergistic effect.

(5) Reducing the amount of the solvent used as the second desensitizer not only improves the color density but also makes the desensitization temperature more sensitive, and is also economical. "Physical properties"
Second, it is effective.

The reason why the desensitization temperature is so sensitive is probably due to these
This is thought to be because desensitizers have difficulty dissolving dyes at low temperatures and also have poor compatibility with the second desensitizer used in combination.

[Brief explanation of drawings]

The drawing is a graph showing the correlation between the color development rate and temperature of the inventive example and the comparative example shown in Table 7.

Claims (1)

[Scope of Claims] 1. Electron-donating coloring dyes, electron-accepting color developers, azomethines or carboxylic acid primary amine salts as the first desensitizer, and alcohols and amides as the second desensitizer 1. A thermoreversible desensitizing composition characterized by containing four components of esters and esters together. 2. The electron-donating coloring dyes, the electron-accepting color developer, the first desensitizer, and the second desensitizer are each 0.0% of the total composition.
1-20% by weight, 0.1-40% by weight, 0.5-20% by weight and 1-50% by weight of the thermoreversible desensitizing composition according to claim 1. 3. The thermoreversible desensitizing composition according to claim 1, wherein the weight ratio of the electron-donating coloring dye to the electron-accepting color developer is 1:1 to 1:5. 4. The weight ratio of the first desensitizer to the second desensitizer is 1:2 to 1:
20, the thermoreversible desensitizing composition according to claim 1.