JPH0124838B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a new and practical thermoreversible desensitizing composition which has extremely wide industrial applicability. [Prior Art] As is known in the art, at a certain temperature it is colorless, but
A specific substance that develops color when exposed to an appropriate temperature, making it possible to recognize the color, or a specific substance that is colored at room temperature but loses or changes color when heated to high temperatures, i.e., a specific substance that exhibits a thermochromism phenomenon. It is used to prepare printing inks, paints, etc., and is used for various applications requiring temperature-sensitive display. Examples of such specific substances or similar substances that exhibit the above effects include salts of transition metals such as cobalt, nickel, and manganese, and hexamethylene, which first release moisture and change color when heated, and then reabsorb moisture and restore color when cooled. There are double salts with aminic amides such as tetramine, as well as mercury iodide, complex salts of mercury iodide and other iodide metal salts, heavy metal compounds such as lead chromate, ammonium metavanadate, etc., dixanetyrene, 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 optionality in color change temperature and color. (4) Discoloration to a similar hue and unclear. Cholesteric liquid crystals or mixtures of cholesteric liquid crystals and nematic liquid crystals are also available as substances exhibiting the thermochromic phenomenon described above, but they have poor color density, no arbitrariness in color and color change temperature, and are extremely expensive. However, due to the following reasons, it has the disadvantage that its applications are significantly restricted. By the way, in recent years, color developers that use normally colorless electron-donating coloring pigments as color components and cause coloration by accepting electrons, such as atabalgide, kaolin clay, zinc chloride, phenols, The thermocopying and coloring methods of thermocopying based on the binding color reaction of electron acceptors such as zinc salicylate, aluminum benzoate, etc. are used, and in addition to these constituents, various solvents, such as alcohols, are used. , esters, ketones, acid amides, and other desensitizing agents exhibiting a so-called desensitizing effect (discoloration phenomenon) are present, and the composition exhibits reversible color development and discoloration upon appropriate external temperature changes. Are known. The advantages of the above composition are that, first, a large number of electron-donating color-forming dyes are already known for each hue, and any of them can be selected arbitrarily; and since all solvents, including water, are desensitizers, Depending on the type, the discoloration temperature can be arbitrarily set within a wide range from low to high temperatures. However, the above composition has the following drawbacks. That is, the solvents must be used in extremely large amounts to produce the desired thermochromic effect, resulting in significant weaknesses in color density limitations and durability, particularly in durability against solvents, washing, and heat. have 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 and obtain a new thermochromic material with extremely excellent performance. That's what I did. [Means for Solving the Problems] Next, the configuration of the present invention will be described. The present invention relates to electron-donating coloring dyes, electron-accepting color developers, azomethines or carboxylic acid primary amine salts as a first desensitizer, and alcohols, amides or esters as a second desensitizer. This is a thermoreversible desensitizing composition characterized by coexisting the following four components. [Example] Electron-donating color pigments as color components of the present invention include 3,3' dimethoxyfluoran (yellow), 3
Chlor 6-phenylaminofluorane (yellow-orange),
3-diethylamino-6-methyl-7-chlorofluorane (vermilion), 3-diethyl-7.8-benzofluorane (peach), crystal violet lactone {3.
3′3″ Tris(P dimethylaminophenyl) phthalide} (blue-purple), malachite green lactone {3.
3'bis(P dimethylaminophenyl) phthalide}
Substituted phenylmethanes and fluorans such as (green), 3-diethylamino, 6-methyl, and 7-phenylaminofluorane (black), various intolyl phthalides, spiropyran, coumarins, etc. , these may be used alone or in combination of two or more thereof. In this case, the amount of the electron-donating color-forming dye is preferably 0.1 to 20% by weight of the total composition. Next, in the present invention, examples of electron-accepting color developers (proton donors) that color the above pigments include phthalic acid, benzoic acid, terephthalic acid, pyromellitic acid, trimellitic acid, toluic acid, oxystearic acid, oxalic acid, lauric acid, stearic acid,
Carboxylic acids such as tartaric acid, citric acid, anthranilic acid and their ammonium salts or metal salts, phenol, P-phenylphenol, β-naphthol, resorcinol, phloroglycine, hydroquinone, dihydroxynaphthalene, bisphenol S, phenolphthalene, phenol Phenols such as resin oligomers and their salts,
Oxycarboxylic acids and their salts such as salicyls, oxybenzoic acid, ethyl oxybenzoate, salomethyl, resorcinic acid, methylenebissalicylic acid, salicylic acid amide, methyl β-oxynaphthoate, and various thiophenols and their derivatives, triazoles. Examples include tetrazoles, mercapto group-containing heterocyclic compounds, thiourea derivatives, phosphoric acid esters, sulfonated compounds, and inorganic compounds such as zinc chloride, tin chloride, and oxyantimony salts. Or two or more types are used. In addition, in the case of the present invention, the electron-accepting color developer (proton donor) described above is 0.1 to 40% by weight of the total composition, and in terms of the relationship with the electron-donating coloring dyes, it is the same. It is preferable that the amount is 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, as one of the desensitizers, azomethines, the following formula (1) ~ (3), which can be easily obtained by mixing aldehydes and amines corresponding to the desired structure and dehydrating the mixture. R-CH=N-R'......(1) R-CH=N-R'-N-CH-R...(2) R-N=HC-R'-CH=N-R...(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: Examples include benzaldehyde, tolualdehyde, anisaldehyde, cyanoaldehyde, chloraldehyde, cuminaldehyde, phenyl acetaldehyde, heliotropin, citral, neral, vanillin, etc., and aliphatic aldehydes include acetaldehyde, butyraldehyde,
Examples of the dialdehyde include hexylaldehyde, palmitylaldehyde, and stearylaldehyde. Examples of the dialdehyde include glutaraldehyde, azifaldehyde, terephthalaldehyde, and glyoxal. 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, Examples include butylamine, laurylamine, myristylamine, palmitylamine, stearylamine, benzylamine, cinnamylamine, etc. Diamines include ethylenediamine, stearylpropylene diamine,
Phenylene diamine, 1,6 diamine hexane,
Examples include 1.8 diaminooctane and benzidine, and further examples of heterocyclic amines include aminopyridine and aminoquinoline. Another first desensitizer in the present invention, the carboxylic acid primary amine salt, is represented by the following formula (4),
Although it can be easily obtained by reacting carboxylic acids and primary amines, it is preferable that the salt is poorly soluble in water. R-(COOH) _x・R'-(NH ₂ ) _y ...(4) (In the formula, x and y are integers, and R and R' are the same as before.) Incidentally, when the above carboxylic acids are listed, For example, aliphatic carboxylic acids include cabrylic acid, cabric acid, lauric acid, myristic acid, stearic acid,
Examples include palmitic acid, linoleic acid, linolenic acid, oleic acid, behenic acid, enanthic acid, sebacic acid, azelaic acid, etc., and examples of aromatic carboxylic acids include benzoic acid, P-chlorobenzoic acid, P-butylbenzoic acid, and 1-naphthalene. Examples include carboxylic acid, cinnamic acid, phenyl complex acid, methacrylic acid, terestalic acid, difuranic acid, dibenzofurancarboxylic acid, cinchoninic acid, and the like. 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,
Examples include aminothiazole and aminopyridine. The above-mentioned first desensitizer should be added in an amount of 0.5 to
It is preferably 20% by weight, and the weight ratio with the second desensitizer described later 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, octadecyl alcohol, ceryl alcohol, and Saturated monohydric alcohols such as syl alcohol, geraniol,
Examples include unsaturated alcohols such as nerol, linalool, oleyl alcohol, and the like. Amides include acetamide, capric acid amide, lauric acid amide, myristic acid amide, stearic acid amide, oxystearic acid amide, bisstearic acid amide,
Acetoacetylamide, acetanilide, paratoluenesulfoamide, benzoic acid amide,
Examples include salicylic acid amide, oxalic acid amide, phthalic acid amide, phthalimide, diethyl urea, thiourea, diphenyl urea, and benzimidazole. 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 above solvent is 1 to 50% by weight based on the total composition.
It is desirable that In the present invention, the solvents are limited to the alcohols, amides, or esters mentioned above because these solvents have the following properties compared to other solvents:
This is because the melting point and softening point can be obtained systematically. By the way, among the first and second desensitizers mentioned above, those with higher boiling points, melting points or freezing points have the property of causing discoloration at higher temperatures, and those with lower ones exhibit their effect at lower temperatures. In this way, the thermochromic temperature range of the present invention can be set to any desired temperature ranging from about -40°C to about 150°C, and a significant color change is observed beyond the set temperature, thus making the color changeable. Temperature discoloration is reversible and repeated. Tables 1 and 2 below are examples of the first desensitizer used in the present invention, and Tables 3, 4, and 5 are examples of the second desensitizer used in the present invention. The decoloring temperature in each table indicates the temperature at which desensitization begins, 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.

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[Table] The above four components in the present invention are used as a mixed solution, emulsion, dispersion, capsule encapsulation, or the like. The encapsulation method and membrane material are not particularly limited, and for these coexistence systems,
Alternatively, the medium containing the coexisting system may contain various agents, such as surfactants, drying regulators, antifoaming agents, resins, crosslinking agents, catalysts, viscosity regulators, dyes, pigments, and optical brighteners, if necessary. agents, ultraviolet absorbers, ultraviolet stabilizers, infrared absorbers, extender pigments, foaming agents,
Water repellent, metal powder, glass sphere, plastic sphere, antioxidant, anti-reduction agent, electrolyte, reducing agent, oxidizing agent, acid-alkali, preservative, chelating agent, dye carrier, oil, fat, fragrance, etc. are appropriately blended. However, it does not depart from the gist of the present invention. For use of 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 in question, and then used in gravure, offset, flexography, screen spraying, etc. It may be applied to the substrate by a known printing method such as spraying with a gun, and then, if necessary, treatments such as drying, heating, UV irradiation, infrared irradiation, etc. are performed. In this way, arbitrary thermoreversible discoloration patterns can be displayed on paper, synthetic resin films, glass, ceramics, leather, metals, etc., and similarly in textile printing, transfer printing, and painting, the printing ink vehicle It can be displayed on fabrics and other materials by a treatment similar to that of compounding. On the other hand, thermoreversibly desensitized molded products can be obtained by optionally blending the composition of the present invention with waxes, synthetic resins, and soaps, or by using the composition in combination with the above-mentioned printed film. Incidentally, products using the thermoreversible desensitizing composition according to the present invention include direct printing, knife coating, or transfer onto colored paper, picture books, towels, handkerchiefs, clothes, stickers, labels, ceramics, glass products, plastic cups, etc. Printed items, or printed items such as beach balls, floats, buckets, cups, bath stirring rods, etc., printed on synthetic resin films, foam moldings (sponges and foams), etc., and then simultaneously molded onto the base material; In addition, items kneaded and molded into wax, synthetic resin, fiber materials, etc., such as soap, doll hair, various molded toys, etc., stuffed dolls, animal toys, clothes, etc.
As with artificial flowers, painted cloth is coated or cut as a base material.
Examples include things that are sewn. 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, the second component, the third component, and the fourth component are electron-donating coloring pigments,
An electron-accepting color developer, a first desensitizer, and a second desensitizer are shown (the same applies hereinafter), and the first component and second component are crystal violet lactone and bisphenol A, respectively. Using. Numbers in parentheses indicate weight percent of various components. Furthermore, in the table, those lacking the third component are comparative examples, and the remaining examples are examples of the present invention.

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[Table] According to Tables 6-1 to 6-3 above, the combined use of the first desensitizer in the composition of the present invention increases the dye concentration and significantly narrows the desensitizing temperature range (blue → colorless). It is clearly recognized that 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] Next, specific examples of the present invention are shown. Example 1 Glassine paper (98
g/m ² ) on the silicone processed surface.
(trade name, acrylic acid ester resin) was applied to the entire surface using a roll coater to a thickness of 85 μm, and after air drying, mirror coated paper (100 g/m ² ) was attached to create a base sheet for tax stickers. 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%
A printing ink consisting of 87 parts of ethyl cellulose/ethyl alcohol solution is printed on a one-point manga style animal screen type (100 mesh), dried, and after removing the solvent, a 200μ polypropylene film is attached to the printed surface and heated. A tax seal was obtained by laminating the bottom. The seal was colorless at a temperature of 3° C. or higher, and a dark blue-purple animal pattern appeared at a temperature of −2° C. or lower, and could be reversibly repeated any number of times. As a comparative example, a tax sticker was obtained in the same manner using only 20 parts of lauryl alcohol without using the P-methoxybenzylidene laurylamine in this example, but the concentration was lower than in this example, and the color change due to temperature was lower. The sharpness was also much lower. 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 was poured into 300 parts of a 20% polyvinyl alcohol aqueous solution heated to 85℃, and the average particle size was adjusted by adjusting the stirring speed.
Disperse into 15μ oil droplets, then add Epicure T
After adding 6 parts of (trade name, curing agent) and heating at 85℃ for 3 hours, the resulting microcapsule particles were filtered through a screen gauze, washed with water, and dried, with an average particle size of 15μ.
108 parts of spherical particles exhibiting a dark green color were obtained. 15 parts of the spherical particles, 2 parts of Glow Yellow MF2G (trade name, fluorescent pigment), and 8 parts of acrylic acid ester emulsion copolymer (solid content 33%) were mixed with 75 parts of oil-in-water emulsion containing 1% ethyl cellulose. A printing paste was obtained. Using the printing paste, a polka dot pattern was printed on a towel fabric 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 printed towel 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 when the temperature of the hot water is lowered to below 30°C, the polka dots become green again. The pattern was restored. 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 Pcumylbenzylidene Panisidine in this example and using only 100 parts of cetyl alcohol, the reversible color change property was good, but The temperature range of discoloration was not sharp, and in order for the toweling material, which had turned into 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-diethylamino-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, and 10 parts of Rigotsurak 2004WM-2 (trade name, unsaturated polyester) were heated and dissolved in advance, and this was stirred into 200 parts of a 6% gelatin aqueous solution. Then, add 0.2 parts of 50% benzoyl peroxide and 0.15 parts of cobalt naphthenate, and continue heating and stirring at 80°C for 10 hours. The produced microcapsule particles were separated by filtration, washed with water, and dried to obtain 39 parts of vermilion spherical particles.
39 parts of the spherical particles were mixed and stirred with 1.5 parts of Demol N (trade name, dispersant) in 150 parts of water, and 2 parts of Sumitekus Resin 501 (trade name, initial combination of urea, melamine, and formaldehyde) was added. Then, 0.1 part of Sumitex Accelerator MX (trade name, curing catalyst) was added, and the mixture was reacted 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 μm. Next, 20 parts of the microcapsule particles were mixed with 1005 parts of Ethocel #10, 10 parts of vinyl chloride/ethylene copolymer resin, and 65 parts of xylol to prepare a printing ink.
Using the printing ink, a gravure plate with an animal silhouette pattern (801 x 100 mm) was printed on a polypropylene transparent film (0.85 mm) and dried. Next, the non-printing side of the film is placed in a container (inner surface of a molding die).
In addition to electrostatically adhering to Noblen Y-100
(trade name, polypropylene resin powder) was injected under pressure and heat to obtain an integrally molded product of the film. In this way, a polypropylene container with an animal silhouette pattern was obtained which was colorless at temperatures above 18°C and turned vermilion at temperatures below 13°C. 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 was low, and the color change temperature range was not sharp; it did not become colorless unless the temperature was above 23°C, and it did not turn completely vermilion unless it was cooled to below 10°C. Example 4 Sumikasen in which 5 parts of the vermilion microcapsule particles obtained in Example 3 can be melted at 110°C in advance
The mixture was quickly kneaded in 95 parts of G807 (trade name, polyethylene resin pellets), then formed into a sheet with a thickness of 0.2 mm, and cooled. In this way, a polyethylene sheet was obtained which was colorless at temperatures above 18°C and turned vermilion at temperatures below 13°C, and was extremely sensitive to temperature. Note that the sheet repeatedly underwent reversible temperature-sensitive discoloration any number of times. Example 5 Glassine paper treated with silicone mold release agent (65
g/m ² ) on top of crystal violet lactone
0.2 parts, bisphenol A 0.4 parts, P cumylbenzylidene P anisidine 0.6 parts, cetyl alcohol 2.4 parts
part, Tinuvin P (trade name, ultraviolet absorber) 0.1 part,
FZ5037 (product name, fluorescent pigment) ethyl alcohol 10
Using a printing ink consisting of 10% ESLETSUKU BM-2 (trade name, polybutyral resin) and 86 parts of ethyl alcohol solution, we screen printed (100 meshes) a design pattern consisting of one-point manga-like figures and reversed letters. Next, Vylon powder (trade name, polyester resin) was sprinkled on the pattern 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 treated at 150° C. for 10 seconds using a hot press to peel off the base sheet. In this way, a transfer printing pattern consisting of a one-point manga-like character pattern and letters appeared on the T-shirt. To actually measure the discoloration temperature of the transfer printing pattern, the temperature was 35℃.
It was pink at temperatures above 30°C and purple at temperatures below 30°C, and was extremely sensitive to temperature changes. In addition, the general dyeing hardness was generally grade 4 or higher, and the texture was soft. As a comparative example, when Pcumylbenzylidene Panisidine in this example was not used, the color did not completely and vividly escape even at 35°C, and the color became pink with a slight bluish tinge. 25℃ for complete color development without a complete purple color
It was necessary to cool down below. Example 6 1 part of 3-diethyl 7.8-benzofluorane, 5(6)
Chlor 1, 2, 3 benzotriazole 2 parts, oleic acid stearylamine 8 parts, oleylamide
30 parts of Coronate T100 (trade name, polyvalent isocyanate) were heated and dissolved in advance, and this was poured into 200 parts of a 5% aqueous solution of Fuji Chemi HECK-150 (trade name, hydroxyethyl cellulose) with stirring. Adjust the speed to obtain an oil droplet dispersion with an average particle size of 25μ. Next is Nituporan 1066 (product name,
20 parts of polyol) were gradually added dropwise and reacted at 45 to 55°C for 8 hours. The thus produced microcapsule particles were filtered through a screen gauze, washed with water, and air-dried to obtain 56.8 parts of colorless 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 stearylamine oleate as in this example, and then made into a cosmetic soap. but at 35℃
It does not become colorless with hot water, but in order to make it colorless, 45
It required immersion in hot water above ℃. Also, the concentration is
It was inferior to this example. Example 7 Colorless polyether-type polyurethane foam (spherical material with a diameter of 6 cm) was mixed with 60 parts of Bondikku 1310F (trade name, water-dispersed polyurethane resin), 10 parts of Matsumin White R-2 (trade name, white pigment), and 10 parts of Matsumin White R-2 (trade name, white pigment). Minfixer F (trade name, urethane crosslinking agent)
After being immersed in a dispersion consisting of 2 parts of water and 28 parts of water, it is dried to form a white urethane resin coating on the surface of the urethane foam. Then, the white spherical object whose surface was covered with urethane resin was bonded.
1310F (product name, water-dispersed polyurethane resin) 60
Part, Glow Yellow MF2G (product name, fluorescent pigment)
1 part, 5 parts of the pink microcapsule particles obtained in Example 6, 2 parts of Matsumin Fixer F (trade name, urethane crosslinking agent), and 32 parts of water, then dried and further heated to 140°C. A drying process was carried out for 3 minutes in a vacuum cleaner to obtain a ball with a diameter of 6 cm, the surface of which was coated with a urethane resin film. The ball turned red at room temperature below 30°C, and turned yellow when placed at room temperature above 35°C or in hot water. The change can be reversibly repeated any number of times. Example 8 A paste prepared by dispersing 2 parts of the missed color capsule particles obtained in Example 6 in 98 parts of Alfasol K (trade name, vinyl chloride resin for slush molding) was used in a mold for slush molding in the shape of an animal. Pour into 180
Preheat at 200°C for 1 to 2 minutes to fill the mold, drain the uncured paste inside the mold, and then heat at 200°C for 2 minutes.
Heat and cure for minutes. After cooling, the contents were removed from the mold to obtain an animal-shaped slush molded product.
The molded product was colorless at temperatures above 35°C and pink at temperatures below 30°C, and these changes could be reversibly repeated any number of times. [Effects of the Invention] (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, and carboxylic acids constituting the latter, etc. There are many types of both. Therefore, the first desensitizers that can be obtained from these methods are of a wide variety, and therefore have the advantage of being able to 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 dissociate bases at high temperatures, their desensitizing function is noticeable even in small amounts. In addition, the amines contained have antioxidant properties 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 together, the drawback that the first desensitizer is somewhat unstable can be compensated for,
This creates a synergistic effect. (5) The reduction in the amount of solvent used as the second desensitizer is
It not only improves the color density, but also makes the desensitization temperature more sensitive, is more economical, and is effective in improving the physical properties when used as a coating. The reason why the desensitizing temperature is so sensitive is probably that these first desensitizers are difficult to dissolve the dye at low temperatures, and are also poor in 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 developer,
Azomethines or carboxylic acid primary amine salts as the first desensitizer and alcohols as the second desensitizer;
1. A thermoreversible desensitizing composition characterized by containing four components of amides or esters. 2 Electron-donating coloring dyes, electron-accepting color developer,
The first desensitizer and the second desensitizer are 0.1 to 20% by weight, 0.1 to 40% by weight, and 0.5 to 20% by weight, respectively, based on the total composition.
% by weight and from 1 to 50% by weight. 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 and the second desensitizer is 1:2.
The thermoreversible desensitizing composition according to claim 1, wherein the ratio is 1:20.