JPH0376783A - Polychroic thermochromic composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can develop a plurality of colors vividly and densely at the same temperature by mixing at least two thermochromic particulate materials which have a hysteresis width and a color respectively different from one another and satisfy specified conditions. CONSTITUTION:The title composition comprises a plurality of thermochromic particulate materials having a hysteresis width (the difference between the average of a bleaching initiating temperature and a bleaching completing temperature and the average of a coloration initiating temperature and a coloration completing temperature) and a color respectively different from one another. It is so established that the hysteresis widths of the thermochromic particulate materials range from 1 to 50 deg.C, the difference between the smaller hysteresis width and the greater hysteresis width is at least 1 deg.C, and the region of the smaller hysteresis width is within the region of the greater hysteresis width. The thermochromic particulate materials are preferably those formed by coating with a hydrophilic high-molecular compound the surface of a particulate material comprising a homogeneous mixture of a thermosetting resin and a thermochromic composition containing an acid color-forming substance, an acidic substance, and a solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides thermochromic compositions, in particular thermochromic compositions containing a plurality of thermochromic granules having different hysteresis widths and colors. The present invention relates to a thermochromic composition that exhibits multiple colors and is capable of exhibiting a plurality of colors at the same temperature.

Conventional technology and its problems Conventionally, thermochromic compositions consisting of three components: an acidic substance, an acid color developing substance, and a solvent change color depending on temperature changes. It is well known that it reversibly changes to colorlessness. It is also known that by using two or more types of thermochromic compositions having different color change temperatures, the color can be changed in multiple stages depending on the temperature. In this case, the color changes gradually become lighter when heated, and conversely becomes darker when cooled, making it possible to obtain multiple colors step by step.
At the same temperature, only one color was obtained.

Therefore, there is a need for a thermochromic composition that can express a plurality of colors vividly and intensely, and that can also express a plurality of colors at the same temperature.

Means for Solving the Problems The present invention provides multiple types of products having mutually different hysteresis widths (difference between the average value of decolorization start temperature and complete decolorization temperature and the average value of color development start temperature and complete color development temperature) and colors. The various hysteresis widths of the thermochromic granules are in the range of 1 to 50°C, and the difference between the small hysteresis width and the larger hysteresis width is 1 C. or higher, and a region with a small hysteresis width is present in a region with a larger hysteresis width.

The present inventor has conducted intensive research on a thermochromic composition comprising a three-part mixture of an acidic substance, an acid color developing substance, and a solvent. In the process, the composition has a so-called hysteresis width between the temperature range where the color changes from colored to colorless (color-erasing temperature range) and the temperature range where color changes from colorless to colored (coloring temperature range). Focusing on the fact that there are some products that have different hysteresis widths and colors, the method contains granulated products of multiple types of thermochromic compositions having mutually different hysteresis widths and colors, and various hysteresis widths of the multiple types of thermochromic granular compositions. is in the range of 1 to 50℃,
A thermochromic property for multicolor development, characterized in that the difference between a small hysteresis width and a larger hysteresis width is 1°C or more, and the area of the small hysteresis width is inherent in the area of the larger hysteresis width. The present invention was completed by discovering that the composition can express multiple colors vividly and intensely by changing the temperature history by cooling or heating, and that multiple colors can be expressed at the same temperature.

The "hysteresis width" referred to in this specification will be explained with reference to FIG. 1. FIG. 1 is a graph showing the relationship between color density and temperature of a thermochromic composition having a hysteresis width. The thermochromic composition is colored up to T (discoloration starting temperature), but the color begins to disappear at a temperature of T1 or higher, and when it reaches T2 (complete discoloration temperature), the color completely disappears. Becomes colorless. When this is cooled, the color that had disappeared at T3 (coloring start temperature) begins to develop, and at Tmu (full coloring temperature), coloring is completed and the original colored state returns.

At this time, the decoloring temperature range (decoloring curve, T1 → T2
) and the color development temperature range (color development thin line, T4←T3). This deviation width is the so-called "hysteresis width", and
The "hysteresis width" is usually "the difference between the average value of the decolorization start temperature and the complete decolorization temperature and the average value of the color development start temperature and the complete color development temperature"
It is expressed as In other words, the hysteresis width (
H).

In the present invention, granules of a plurality of types of thermochromic compositions having mutually different hysteresis widths and colors are used. These multiple types of hysteresis widths must have the following specific relationship. First, the hysteresis widths of the plurality of types are all in the range of 1 to 50°C. If the hysteresis width is less than 1° C., it is difficult to obtain a clear color change. Furthermore, it is extremely difficult at present to obtain a composition with a hysteresis width exceeding 50°C. Then, the difference between the small hysteresis width and the larger hysteresis width is 1° C. or more. The difference is 1℃
If it is less than that, it is difficult to obtain a clear color change. Moreover, the region of small hysteresis width is inherent in the region of larger hysteresis width. If it is not internal, it is difficult to obtain clear color changes. Moreover, since the discolored regions of the granules overlap, the number of colors that can be developed is reduced. The composition of the present invention containing n thermochromic granules can exhibit 2'' colors at the same temperature, but cannot exhibit 2n colors if the discolored regions overlap.

The thermochromic composition used in the present invention is not particularly limited as long as its hysteresis width is in the range of 1 to 50°C. The composition usually contains three components: an acid developer, an acidic substance, and a solvent.

Specific examples are given below.

Known acid color developing substances can be used, for example,
3,3-dimethoxyfluorane, 3-chloro-6-phenylaminofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethyl-7,8-benzofluorane, 3°3' 3 '-tris(P-diethylaminophenyl)phthalide, 3,3'-bis(P-
Examples include substituted phenylmethanes such as (dimethylaminophenyl)-7phenylaminofluoran, fluorans, indolylphthalides, spiropyrans, coumarins, and the like. Acid color developing substances can be used alone or in combination of two or more.

Known acidic substances can be used to develop the color by combining with the acid color developing substance, such as P-phenylphenol, bisphenol A, bisphenol F1 cresol, meditol, chloroglycine, phenolic resin oligomer, β
- Phenols such as naphthol, 5-chlorobenzotriazole, 4-laurylaminosulfobenzotriazole, 5゜5'-methylenebis-benzotriazole,
Examples include 1,2°3-benzotriazoles such as 5-carpoethoxybenzotriazoles, and the acidic substances may be used alone or in combination of two or more.

Known solvents can be used to coexist the acid color developing substance and the acidic substance, such as alcohols such as octyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, cyclohexanol, geraniol, and pentauryl alcohol. esters such as decyl caprate, myristyl caprate, lauryl laurate, lauryl myristate, stearyl palmitate, cecyl benzoate, benzyl benzoate, dilauryl phthalate, lauryl stearate, glyceride palmitate, benzylidene aniline, benzylidene Examples include azomethines such as laurylamine, amides such as acetamide and stearamide, alcohols such as lauryl alcohol/acrylonitrile adducts, myristyl alcohol, acrylonitrile adducts, stearyl alcohol/acrylonitrile adducts, and acrylonitrile adducts. can.

The solvents may be used alone or in combination of two or more.

The thermochromic composition can be produced by mixing the above three components. The blending ratio of the three components is not particularly limited and can be appropriately selected from a wide range, but the usual weight ratio is 1 part of the acid developer
To that, the acidic substance is about 0.2 to 20, and the solvent is about 0.
It is sufficient to mix about 5 to 50.

The above-mentioned thermochromic composition may contain various drugs, as necessary.
For example, appropriate amounts of surfactants, drying regulators, viscosity modifiers, dyes, pigments, metal powders, metal soaps, foaming agents, ultraviolet absorbers, antioxidants, reduction inhibitors, flame retardants, and antistatic agents are used. You can leave it there.

In the present invention, a granulated product of the thermochromic composition described above is used. The granular material is, for example, a thermochromic composition encapsulated according to a known method, a thermochromic composition mixed with a thermosetting resin, granulated, and then coated with a hydrophilic polymer compound. Among them, the latter granules are preferred.

Specifically, the granular material can be manufactured as follows.

That is, first, a thermochromic composition and a thermosetting resin,
Heat and mix evenly. Known thermosetting resins can be used, such as polyurethane resins, epoxy resins, melamine resins, phenol resins, diallyl phthalate resins, and epoxy phthalate resins.

The thermosetting resin may be used in an amount of 5 to 50 parts by weight based on 100 parts by weight of the three-component mixture.

Next, the mixture is granulated, for example, the mixture is stirred and emulsified in hot water containing an emulsifier, a catalyst is added if necessary, and heating is continued.

A thermochromic granule can be obtained by further coating the surface of the granule obtained above with a hydrophilic polymer compound. The hydrophilic polymer compound in the present invention may be one that coagulates with acids, alkaline electrolytes, heavy metals, aldehydes, and relatively ionic substances. Specific examples include natural polymer compounds such as alginate, carrageenan, and peptin, semi-synthetic polymer compounds such as carboxymethylcellulose, carboxymethylated starch, and carboxymethylated guar gum, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic amide, Examples include polymaleic acid copolymers, and one or more of these can be used. The hydrophilic polymer compound may be used in an amount of 5 to 50 parts by weight based on 100 parts by weight of the three-part mixture.

The thermochromic granules obtained in this way have solvent resistance,
Since it has extremely excellent gas permeability, heat resistance, pressure resistance, and light resistance, it can permanently maintain the thermochromic function according to the present invention.

Commercially available products can also be used as the thermochromic granular material. Specifically, for example, there may be mentioned a product sold by the applicant under the trade name "Chromic Color 'History'".

The composition of the present invention can be produced by mixing two or more thermochromic granules having mutually different hysteresis widths and colors and satisfying the above-mentioned conditions.

There is no limit to the number of granules to be mixed, but if a large number are mixed, the colors will overlap too much and the entire surface will be black, so it is usually preferable to mix about 2 to 4 granules. The particle size of the granules is not particularly limited, but is usually about 1 to 50 μm, preferably 3 μm.
A material with a diameter of about 15 μm may be used.

The composition of the present invention can be applied to various articles in the same manner as conventional thermochromic compositions. For example, synthetic resin, synthetic fiber,
It can be blended in appropriate amounts with waxes, low-molecular monomers, PVC paste resins, etc. to make molded products, fibers, films, etc., or it can be blended with oil-based or water-based printing inks, paints, etc.
Paper, synthetic resin molded products, synthetic resin films, textile fabrics, knitted fabrics, mono or multifilament, glass, ceramics,
It is possible to form multicolor thermochromic patterns or multilayers on leather, metal, wood, etc.

Effects of the Invention The multicolor-revealing temperature-sensitive color-changing composition of the present invention expresses multiple colors vividly and intensely, and moreover, can express multiple colors at the same temperature. Variety and dramatic and unexpected color changes can be imparted to various products, significantly increasing the added value of the products.

For example, if the composition of the present invention is applied to a board, etc., by using different hot pens (cold pens) with different temperatures,
It is possible to draw designs, characters, etc. in different colors, and the design can be erased partially or completely depending on the frequency of use, importance, confidentiality, etc., and repeated over and over again. It can also be used. Furthermore, since colors can be maintained within a specific temperature range, past temperatures can be stored in color.

EXAMPLES Below, Examples and Comparative Examples will be given to further clarify the present invention. In the examples, "parts" and "%" refer to "parts by weight" and "% by weight," respectively, unless otherwise specified.

Example 1 Temperature-sensitive color-changing pattern [Product name: Chromic Color "History Turquis Blue 810-40," manufactured by Matsui Shiki Kagaku Kogyo Co., Ltd. (Blue below 10°C, colorless above 40°C,
Hysteresis width H, = 30°C), Figure 2-1] Part 10,
Temperature-sensitive color-changing granular material ■ [Product name: Chromic Color "History Vermilion 818-28," manufactured by Matsui Shiki Kagaku Kogyo Co., Ltd. (Vermilion below 18°C, colorless above 28°C, hysteresis width H, = 10°C) , Figure 2-2] 10 parts, amino-alkyd cocondensation resin [Product name: Beccosol M-
7610-50, manufactured by Dainippon Ink Chemical Industry ■] 80 copies,
A paint was prepared consisting of 30 parts of aromatic naphtha (trade name: Solbetsuso #100, manufactured by Esso Kagaku ■), 10 parts of cellosolve acetate, and 10 parts of isopropyl alcohol.

The hysteresis width of the thermochromic granular material (2) is inherent in the hysteresis width of the granular material (I).

After surface-treating the aluminum minicar, a white paint consisting of titanium oxide and amino alkyd resin was applied electrostatically to form a white layer. Next, the above coating material was electrostatically applied to the entire surface of the white layer, left for 5 minutes, and then heat treated at 130° C. for 20 minutes to form a discolored layer.

Furthermore, the entire surface of the discoloration layer was electrostatically coated with a paint consisting of the above amino alkyd resin and thinner to form a top coat, thereby obtaining a thermochromic miniature car.

As shown in Figures 2-3 and 2-4, this minicar is cooled to below about 10°C and turns purple when heated (1
) retains its purple color at about 10 to about 28°C;
It turned blue at ~40°C, and (3) became colorless at about 40°C. When this was cooled, it remained colorless up to about 18°C, but (4) it turned red at about 10 to 18°C, and (5) it turned purple again at about 10°C. When cooled in step (2), it remained blue until about 18°C.

Further, when heated in step (4), the color remained red up to about 30°C. In other words, by changing the temperature history by cooling or heating, it is possible to simultaneously develop four colors (purple, blue, red, and colorless (white)) in a temperature range of about 18 to 30 degrees Celsius, or to create one color of your choice. You can enjoy a variety of color changes by making the color appear or changing dramatically from blue to red or vice versa.

Comparative Example 1 The thermochromic granules used in the paint for forming the discoloration layer of Example 1 were replaced with thermochromic granules ■ [Product name: Chromic Color Turquis Blue 5-15, ■ Matsui Dyes Manufactured by Kagaku Kogyo Co., Ltd. (blue below 15℃, colorless above about 15℃)
], and temperature-sensitive color-changing granular material ■ [Product name: Chromic Color Vermilion 5-30, ■ Manufactured by Matsui Shiki Kagaku Kogyo Co., Ltd., vermilion below about 30°C, colorless above about 30°C]] A miniature car was manufactured in the same manner as in Example 1.

Thermochromic granules (1) and (2) have a hysteresis width of less than 1°C.

As shown in Figure 4, this miniature car becomes purple when it is below 15 degrees Celsius, vermilion when it is above 15 degrees Celsius and below 30 degrees Celsius, and white when it is above 30 degrees Celsius, and the color changes from purple to vermilion and white or vice versa depending on the temperature change. However, at the same temperature, it shows only one color.

Example 2 Thermochromic granular material I (Chromic Color "History" Turquis Blue 810-40) 5 parts, thermochromic granular material ■ (Chromic Color "History" Vermilion S
-18-28) 5 parts, thermochromic granular material■ [Product name: Chromic Color "History" First 20-8-4
-46, ■ Manufactured by Matsui Shiki Kagaku Kogyo Co., Ltd. (yellow below 4℃,
Colorless hysteresis width HV = 42°C above 46°C), Figure 3-1] 5 parts, 25% of ethylene-vinyl acetate copolymer resin [trade name: EV-40, manufactured by Mitsui Toatsu Chemical Industry ■]
A printing ink consisting of 85 parts of xylene solution was prepared.

Parchment paper with silicone treatment on one side (98g)
/cd) was coated with an adhesive [trade name: SK Dyne 101, manufactured by Block Chemical Industry ■] over the entire surface to a thickness of 40 μm using a coater, and after air-drying, a polyester film (thickness 25 μm) was placed on top of it. I made a base sheet for pasting and tack sealing. The above printing ink is applied to the entire surface of the polyester film of the base sheet using a screen plate (
100 mesh) and dried thoroughly. Next, apply adhesive [Product name: SK Dyne 200] to the screen-printed surface and the transparent polypropylene film (thickness 50 μm) surface.
A, manufactured by Mitsui Toatsu Chemical Industries, Ltd.] was coated on the entire surface, air-dried, and laminated onto a sheet, followed by lamination under heat to obtain a thermosensitive color-changing tack seal.

As shown in Figures 3-2 and 3-3, this tack seal (1) turns black when cooled to about 4℃, and when heated (2) remains black until about 28℃; (3) It turned yellow at about 40-46℃. When it was cooled, about 1
It remains yellow up to 8℃, but (4) about 10-18℃
It turned orange. (5) When the yellow color of (3) above was heated, it became colorless at about 46°C. When this is cooled, it is approximately 18℃
(6) It turned red at about 10-18°C, and (7) it turned purple at about 4-10°C. When heated, it remains purple until about 28°C, but (8) about 28°C.
It turned blue at ~40°C. And when <7> is cooled,
It turned black again at about 4°C. These colors (1) to (8) remain even when heated or cooled in a temperature range of about 18 to 28°C.
The color remained the same. That is, by changing the temperature history, it is possible to exhibit eight colors: black, green, orange, yellow, purple, blue, vermilion, and colorless in a temperature range of approximately 18 to 28°C.

After heating this tack seal to about 46℃ to make it colorless,
For example, if you stick it in a greenhouse and leave it overnight, you can tell the lowest temperature by the change in color. That is, in the case of red, the temperature is 10 to 18°C, in the case of purple, it is 4 to 10°C, and in the case of black, it is 4°C or less. Also, if the tack seal is cooled and turned black, the maximum temperature can be determined.

Example 3 10 parts of thermochromic granular material ■ (Chromic Color "History" Turquis Blue S-10-40), 10 parts of thermochromic granular material ■ (Chromic Color "History" Vermilion S-18-28) 1 part, 50 parts of low molecular weight polypropylene resin [trade name: Viscol 330-P, manufactured by Sanyo Chemical Industries, Ltd.], and 30 parts of polypropylene resin [trade name: Noblen AZ961, manufactured by Sumira Chemical Industries, Ltd.] in a V-shaped tumbler. After mixing, the mixture was heated and melted at 140° C. in a stainless steel double pot equipped with a stirring blade.The melt was cooled in a table flaker to obtain a flaky thermochromic color masterbatch.

25 parts of this masterbatch and 75 parts of a polypropylene resin [Noblen FL6315G, manufactured by Sumitomo Chemical Industries, Ltd.] were mixed in a tumbler mixer, and the mixture was molded in an extruder to obtain a film with a thickness of 50 μm. This film was laminated to a white polyester sheet to produce a writing board.

The board was heated to 40°C to erase the color caused by the thermochromic granules and turned white, then letters and designs (colored red) were drawn with a cold pen at about 16°C, and then with a cold pen at about 8°C. I drew different letters and designs (colored blue). When I touched these with my finger, only the red letters and designs disappeared. If you use a cold pen at about 16 degrees Celsius, you can draw red letters and designs as many times as you like.

Also, by exposing it to warm air at 40℃, all the letters will be erased and it can be used over and over again.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the relationship between the color change density and temperature of a thermochromic composition having a hysteresis width. FIGS. 2-1 and 2-2 are diagrams showing discoloration patterns of thermochromic granular materials I and (2) having a hysteresis range. 2nd-
3 and 2-4 are drawings showing discoloration patterns of minicars coated with the composition of the present invention. FIG. 3-1 is a drawing showing a color change pattern of thermochromic granular material V having a hysteresis width. Figures 3-2 and 3-3 are drawings showing discoloration patterns of tack seals to which the composition of the present invention is applied. FIG. 4 is a drawing showing the discoloration pattern of a miniature car coated with a mixture of thermochromic granules (1) and (2) without a hysteresis width. (That's all) Fig. 4T3T1 ``JMl, return 2 Fig. 2-1 Fig. 0 20 30 1 degree (°C) 0 Fig. 2-2 0 030 SA /l(''C) 0 Fig. 2-3 0 820 0 0 0

Claims (2)

[Claims] (1) Contains multiple types of thermochromic granules having mutually different hysteresis widths (difference between the average value of decolorization start temperature and complete decolorization temperature and the average value of color development start temperature and complete color development temperature) and colors. The various hysteresis widths of the plurality of types of thermochromic granules are in the range of 1 to 50°C, and the difference between the small hysteresis width and the larger hysteresis width is 1°C or more, and the small hysteresis width is in the range of 1 to 50°C. 1. A thermochromic composition for multicolor development, characterized in that the width region is included in a larger hysteresis width region. (2) The thermochromic granular material is a homogeneous mixed granular material of a thermosetting resin and a thermochromic composition containing three components: an acid color developing substance, an acidic substance, and a solvent, and is made of a hydrophilic polymer compound. The composition according to claim 1, which is formed by surface coating.