A specially formulated pressure-sensitive film color-developing coating and its preparation method and application

Abstract

The present invention relates to the technical field of pressure-sensitive paper, and in particular to a specially formulated pressure-sensitive film color-developing coating, and a preparation method and application thereof, wherein the color-developing coating comprises the following components in parts by weight: 70-100 parts of activated clay, 5-30 parts of a modifier, 15-25 parts of a binder, and 2-2.5 parts of an auxiliary agent. The color-developing coating is prepared by the following preparation method: the activated clay, the modifier, the binder, and the auxiliary agent are mixed to obtain the target product. The color-developing coating is applied to a substrate, and then dried to obtain a pressure-sensitive lower film. Compared with existing inorganic clay color-developing coatings, the color-developing coating of the present invention has a higher color density; compared with existing organic synthesis color-developing coatings, the color-developing coating prepared by the present invention is more resistant to high temperatures, is not easy to adhere to other coatings, and has a color density comparable to that of existing organic synthesis color-developing coatings.

Description

Technical Field

[0001] The invention relates to the technical field of pressure-sensitive paper and pressure-sensitive polymer film, and in particular to a specially formulated pressure-sensitive film color-developing coating and a preparation method and application thereof. Background Art

[0002] The electron accepting colorants used in the existing pressure-sensitive paper and polymer film coating layer are mainly inorganic clay materials and organic synthesis materials. The inorganic clay materials are products treated with acid such as bentonite, kaolin, zeolite, and algae. Such colorants react with electron-donating dye precursors to open the ring for color development. The reaction is reversible. In the air with high humidity and other oxidizing gases, it is easy to fade, reducing the color density, and the color density of inorganic clay is lower than that of organic synthesis colorants. Organic synthesis colorants are alkylhydroxybenzoic acid and its modified products, as well as oil-soluble phenolic resin and its modified products. They react chemically with dye precursors to develop colors, with bright colors and high density. However, in a high temperature use environment, the color will fade, and the color marks will melt and adhere to the coating on other base papers or films. Summary of the invention

[0003] In order to overcome at least one of the following defects in the prior art:

[0004] 1) The color density of inorganic clay developers in pressure-sensitive paper and film coating layer is low;

[0005] 2) Organic synthetic color developers are not resistant to high temperatures, can easily reduce color development, and can easily adhere to other coatings.

[0006] The invention provides a specially formulated pressure-sensitive film color-developing coating and a preparation method and application thereof.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] One of the technical solutions of the present invention provides a pressure-sensitive film color-developing coating, which includes the following components in parts by weight:

[0009]

[0010]

[0011] Furthermore, the modifier is a strong acid and weak base salt, and the strong acid and weak base salt includes one or more of ammonium sulfate, magnesium sulfate, aluminum sulfate, zinc sulfate, ammonium chloride, magnesium chloride, aluminum chloride or zinc chloride.

[0012] Furthermore, the strong acid and weak base salt is preferably aluminum chloride.

[0013] Furthermore, the strong acid and weak base salt is preferably a mixture of zinc chloride and zinc sulfate, and the mass ratio of zinc chloride to zinc sulfate in the mixture is 1-3:1, preferably 1:1.

[0014] The above-mentioned multiple strong acid and weak base salts can be used in combination to give the clay layered structure more active acid centers, which are conducive to accepting more electrons from dye precursors to produce chemical reactions and thus improve the color density.

[0015] Furthermore, the modifier is a solid superacid.

[0016] Furthermore, the solid superacid includes one or more of a solid superacid compounded with an inorganic salt, a heteropolyacid solid superacid, a solid superacid loaded with a metal oxide, or a halogen-containing solid superacid.

[0017] Furthermore, the solid superacid is preferably SO 4 2ˉ / TiO 2 Type solid superacid.

[0018] Furthermore, the solid superacid is preferably SO 4 2ˉ / TiO 2 Solid superacid and SO 4 2ˉ / ZrO 2 -WO 3 A mixture of solid superacids containing SO 4 2ˉ / TiO 2 Solid superacid and SO 4 2ˉ / ZrO 2 -WO 3 The mass ratio of the solid superacid is 1-2:1, preferably 1:1.

[0019] The above-mentioned solid superacids are inorganic substances comparable to the inorganic strong acid sulfuric acid, but without the corrosiveness of sulfuric acid. They have strong performance in reacting with dye precursors. After compound use, they can enhance the reaction activity and thus improve the color density.

[0020] Furthermore, the modifier is an organic synthetic acidic compound, and the organic synthetic acidic compound includes one or more of straight-chain fatty acids, straight-chain fatty acid magnesium salts, straight-chain fatty acid aluminum salts, straight-chain fatty acid calcium salts, straight-chain fatty acid zinc salts, straight-chain fatty acid nickel salts, aromatic carboxylic acids, aromatic carboxylic acid magnesium salts, aromatic carboxylic acid aluminum salts, aromatic carboxylic acid calcium salts, aromatic carboxylic acid zinc salts, aromatic carboxylic acid nickel salts, oil-soluble phenolic resins or zinc-modified oil-soluble phenolic resins.

[0021] Furthermore, the organic synthetic acidic compound is preferably a metal zinc-modified phenolic resin.

[0022] Furthermore, the organic synthetic acidic compound is preferably a mixture of metal zinc modified phenolic resin and 3,5-dibenzyl zinc salicylate, wherein the mass ratio of metal zinc modified phenolic resin to 3,5-dibenzyl zinc salicylate in the mixture is (2-5):3, preferably 2:3.

[0023] The above-mentioned organic synthetic acidic compound modifier metal-modified phenolic resin has excellent resistance to oxygen aging and ultraviolet aging, but its chemical reaction rate with dye precursor is relatively slow. The chemical reaction rate of aromatic carboxylic acid metal salt with dye precursor is relatively fast, and the color is bright, but the oxidation resistance is poor and the degradation rate is fast. The combination of the two can give full play to the advantages, make up for the defects, obtain excellent performance, and maintain good color density.

[0024] The modifier is preferably a mixture of strong acid and weak base salts, solid superacids and organic synthetic acidic compounds.

[0025] Preferably, the modifier is aluminum chloride, SO 4 2ˉ / TiO 2 A mixture of solid superacid and metal zinc modified phenolic resin, wherein aluminum chloride, SO 4 2ˉ / TiO 2 The mass ratio of the solid super acid to the metal zinc modified phenolic resin is (1-3): 1:1, preferably 1:1:1.

[0026] Preferably, the modifier is aluminum chloride, zinc sulfate, SO 4 2ˉ / TiO 2 A mixture of solid superacid, metal zinc modified phenolic resin and 3,5-dibenzyl salicylic acid zinc, the mixture contains aluminum chloride, zinc sulfate, SO 4 2ˉ / TiO 2 The mass ratio of the solid super acid, the metal zinc modified phenolic resin and 3,5-dibenzyl zinc salicylate is 1-2:3:5:2:1-3, preferably 2:3:5:2:3.

[0027] The above three types of modifiers, strong acid and weak base salts, solid superacids, and organic synthetic acidic compounds can be used in combination. After compounding, they can simultaneously give the clay layered structure more active acid centers, enhance the reaction activity, and improve the color brightness, thereby improving the color density.

[0028] The acid-treated clays and organic synthetic compounds commonly used in the market have their own advantages and disadvantages. Clays have a large specific surface area and a large number of acid centers. They can absorb the microcapsule core solvent containing dye precursors quickly and develop color quickly. However, the disadvantage is that the color is not bright and the color easily fades or becomes lighter when encountering moisture and oxidizing components in the environment. Organic synthetic compounds are acidic compounds that can be dissolved in the microcapsule core solvent containing dye precursors, thereby chemically reacting with the dye precursor to develop color. The color is brighter, but the disadvantage is that organic compounds cannot tolerate higher temperatures, causing color changes and turning into a molten state, thereby adhering to the film and causing the coating to fall off. Combining clay with the above-mentioned organic synthetic acidic compounds can obtain a coating with high color density and stable coating that does not fall off at high temperatures.

[0029] Furthermore, the binder includes three or four of starch, gelatin, styrene-butadiene latex or polyvinyl alcohol (PVOH).

[0030] Furthermore, the auxiliary agent is an interfacial tension regulator and a rheology modifier.

[0031] Furthermore, the interfacial tension regulator includes Tween-20 or sodium salt of dioctyl sulfosuccinate.

[0032] Furthermore, the rheology modifier includes sodium polyacrylate or sodium carboxymethyl cellulose.

[0033] A second technical solution of the present invention provides a method for preparing the above-mentioned pressure-sensitive film color-developing coating, the preparation method comprising:

[0034] The activated clay, modifier, binder and additive are mixed to obtain the target product.

[0035] The third technical solution of the present invention provides the application of the above-mentioned pressure-sensitive film color-developing coating, which is coated on a substrate and then dried to obtain a pressure-sensitive lower film. Here, the pressure-sensitive lower film refers to the color-developing lower layer of the pressure-sensitive film, and the color-developing upper layer of the pressure-sensitive film is a film coated with a dye precursor that provides electron donation (i.e., a pressure-sensitive upper film). The electron-accepting substance in the color-developing coating of the pressure-sensitive lower film can react with the electron-donating dye precursor in the pressure-sensitive upper film to develop color.

[0036] Furthermore, the coating amount of the color-developing coating is 10 to 15 g / m 2 .

[0037] The role of adding strong acid and weak base salts and / or solid super acid modifiers to clay is to cooperate with clay to improve the ability of the coating to accept electrons, thereby achieving the purpose of increasing color density. Clay with strong adsorption capacity can adsorb more solvents and dye precursors in the capsule core transferred from the pressure-sensitive upper film. Clay can also maintain the stability of the coating inside and the bonding with the substrate.

[0038] The purpose of adding organic synthetic acidic compound modifiers to clay is to utilize the clay's strong adsorption capacity to adsorb more solvents and dye precursors in the capsule core transferred from the pressure-sensitive upper membrane, and organic synthetic acidic compounds have brighter color rendering properties. Clay cooperates with organic synthetic acidic compounds to achieve high density and brightness of color rendering, while maintaining stable adhesion inside the coating and to the substrate.

[0039] The binder in the formula of the present invention mainly plays two roles: 1) bonding the clay particles of the coating; 2) bonding the coating and the substrate. If the binder is added in too low a proportion, the bonding is insufficient, while if it is added in too high a proportion, the micropores between the particles will be blocked, hindering the diffusion of the solvent and dye precursor in the capsule core, so the binder ratio needs to be controlled within a certain range. Although styrene-butadiene latex and polyvinyl alcohol (PVOH) binders have strong bonding force, the surface film they form is dense, which is not conducive to the diffusion of the solvent and dye precursor in the capsule core. Adding starch and gelatin to form a composite binder (CO-BINDER) can reduce the density and ensure the diffusion of the solvent and dye precursor in the capsule core.

[0040] In order to facilitate better coating and form a coating with good performance, it is necessary to add sodium carboxymethyl cellulose or sodium polyacrylate rheology modifiers to the prepared coating to improve the fluidity and ductility of the coating; add Tween-20 or sodium sulfonated dioctyl succinate interfacial tension regulator to reduce the interfacial tension of the coating, enhance the penetration performance of the coating, make the coating particles better bonded together, and make the coating particles better bonded to the substrate.

[0041] The beneficial effects of the present invention are:

[0042] 1) Compared with the existing inorganic clay-based color developers, the color development density of the pressure-sensitive film color development coating of the present invention is higher, up to 0.78;

[0043] 2) Compared with existing organic synthetic color developers, the color coating prepared by the present invention is more resistant to high temperatures (up to 200°C), is not easy to adhere to other coatings, and the color density (0.78) is comparable to that of existing organic synthetic color developers (color density 0.79). BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the pressure-sensitive color trace diagram of pure clay material at room temperature 23°C;

[0045] Figure 2 This is the pressure-sensitive color trace diagram of the pressure-sensitive film prepared in Comparative Example 1 at room temperature 23°C;

[0046] Figure 3 This is the pressure-sensitive color trace diagram of the pressure-sensitive film prepared in Example 3 at room temperature 23°C;

[0047] Figure 4This is a color line drawing printed at 200° C. on the pressure-sensitive film prepared in Comparative Example 1;

[0048] Figure 5 This is a color line drawing printed at 200°C on the pressure-sensitive film prepared in Example 3. DETAILED DESCRIPTION

[0049] In the following examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0050] In the following examples, the SO 4 2ˉ / TiO 2 The solid superacid is prepared by the following preparation method: titanium dioxide is added with 20% sulfuric acid and soaked for 15 hours, then filtered, dried, and then roasted in a muffle furnace at 550° C. for 4 hours, and finally crushed and sieved to obtain the product.

[0051] In the following examples, the SO 4 2ˉ / ZrO 2 -WO 3 The solid superacid is prepared by the following preparation method: zirconium oxychloride octahydrate ZrOCl 2 8H 2 O is dissolved in concentrated ammonia water to generate a white precipitate, which is then filtered and washed until there is no chloride ion, and dried at 90-120℃ to obtain ZrO 2 ·H 2 O, then add H 2 WO 4 The mixture was mixed and ground evenly, then rinsed with 20% sulfuric acid, calcined in a muffle furnace at 500° C. for 3 hours, and finally crushed and sieved to obtain the product.

[0052] In the following examples, the metal zinc modified phenolic resin used was purchased from Scandinavian Company, USA.

[0053] In the following examples, the 3,5-dibenzyl salicylate zinc used was purchased from Nopco, Japan.

[0054] In the following examples, the "treated clay" used is activated clay, which is obtained by treating bentonite produced in western Fujian. The treatment process is referenced in: Dai Jincao, Huang Jitai. Application of High-efficiency Activated Clay - Preparation and Research of NCR Paper CF Coating [J]. Chemical World, 1993, 34(10):3. DOI:CNKI:SUN:HXSS.0.1993-10-001.

[0055] In the following examples, the "electron donating dye precursor film" (pressure-sensitive film) used was prepared by the following preparation method: 100 parts of a commercially available electron donating dye precursor microcapsule suspension, 5 parts of starch, 5 parts of styrene-butadiene latex, 5 parts of PVOH, 1 part of a rheology modifier, sodium carboxymethyl cellulose, and 0.3 parts of Tween-20 interfacial tension regulator were stirred and mixed to form a coating solution, and 12 g / m2 of the coating solution was coated on the substrate using a slit coater. 2 , and then dried in an oven at 70°C to obtain a pressure-sensitive film. The electron-donating dye precursor in the microcapsule is crystal violet lactone when blue is required, and is 3,3-di(1-butyl-2-methylindol-3-yl)phenolphthalein when red is required.

[0056] In the following examples and comparative examples, the preparation process was carried out at room temperature and the drying temperature was 98°C.

[0057] In the following pressure-sensitive film printing tests of the embodiments and comparative examples, the printer used was EPSON LQ-630KⅡ, and the 3rd gear printing was set.

[0058] Line pressure test: Zhiqu pressure testing machine, model ZQ-990A, set to 200℃, pressure 0.28MPa, time 5 seconds.

[0059] In the drawings involved in the following embodiments and comparative examples, the blue ones correspond to the pressure-sensitive films prepared by using paper base, and the red ones correspond to the pressure-sensitive films prepared by using PET film.

[0060] Example 1

[0061] Add 100 parts of treated clay, 15 parts of aluminum chloride, 10 parts of starch, 5 parts of gelatin, 6 parts of styrene-butadiene latex, 3 parts of PVOH, 2 parts of sodium carboxymethyl cellulose, and 0.3 parts of Tween-20 interfacial tension regulator into the stirring kettle in sequence, stir and mix well to form a coating liquid, and use a wire rod to coat 15g / m2 on the paper base and PET film respectively. 2 The pressure-sensitive films were then dried to obtain the pressure-sensitive films. The pressure-sensitive films were printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: the color density was 0.65, and the color lines printed at 200°C did not fall off.

[0062] Example 2

[0063] Add 70 parts of treated clay into the stirring tank, SO 4 2ˉ / TiO 230 parts of solid super acid, 10 parts of starch, 4 parts of gelatin, 5 parts of styrene-butadiene latex, 2 parts of PVOH, 2 parts of sodium polyacrylate as rheology modifier, 0.2 parts of sodium sulfonated dioctyl succinate interfacial tension regulator, stir and mix well to make a coating solution, and use a wire rod to coat 12g / m2 on the paper base and PET film respectively. 2 The pressure-sensitive film was then dried to obtain the pressure-sensitive film. The pressure-sensitive film was printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: the color density was 0.63, and the color lines printed at 200°C did not fall off.

[0064] Example 3

[0065] In the stirring kettle, 100 parts of treated clay, 5 parts of metal zinc modified phenolic resin, 8 parts of starch, 6 parts of styrene-butadiene latex, 3 parts of PVOH, 2 parts of rheology modifier sodium carboxymethyl cellulose, and 0.2 parts of sodium salt of dioctyl sulfonate succinate interfacial tension regulator were added in sequence, and the mixture was fully stirred to form a coating liquid. 10 g / m2 of the coating liquid was applied on the paper base and PET film respectively using a wire rod. 2 The obtained pressure-sensitive film was printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: color density 0.75, pressure-sensitive color traces as shown Figure 3 as shown; Figure 5 As shown, the color lines printed at 200°C did not fall off.

[0066] Compared with Comparative Example 1, it can be seen that the non-stick coating effect of the pressure-sensitive film prepared by the clay material composite modifier in this embodiment at high temperature is better than that of the pressure-sensitive film prepared by using a pure organic synthetic color-developing material, that is, the color-developing coating prepared in this embodiment is more resistant to high temperatures and is not easy to adhere to other coatings; and the color brightness and color density of this embodiment are close to those of the pure organic synthetic color-developing material in Comparative Example 1.

[0067] Compared with the pressure-sensitive membrane prepared by pure clay material in Comparative Example 2, it can be seen that the pressure-sensitive membrane prepared by the clay material composite modifier in this example has significantly improved pressure-sensitive color brightness and color density at room temperature.

[0068] Example 4

[0069] Add 100 parts of treated clay, 6 parts of zinc chloride, 6 parts of zinc sulfate, 10 parts of starch, 5 parts of gelatin, 6 parts of styrene-butadiene latex, 3 parts of PVOH, 2 parts of sodium carboxymethyl cellulose, and 0.3 parts of Tween-20 interfacial tension regulator into the stirring kettle in sequence, stir and mix well to form a coating liquid, and use a wire rod to coat 15g / m2 on the paper base and PET film respectively. 2The pressure-sensitive film was then dried to obtain the pressure-sensitive film. The pressure-sensitive film was printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: the color density was 0.69, and the color lines printed at 200°C did not fall off.

[0070] Example 5

[0071] Add 70 parts of treated clay into the stirring tank, SO 4 2ˉ / TiO 2 15 parts of solid superacid, SO 4 2ˉ / ZrO 2 -WO 3 15 parts of solid super acid, 10 parts of starch, 4 parts of gelatin, 5 parts of styrene-butadiene latex, 2 parts of PVOH, 2 parts of sodium polyacrylate as rheology modifier, 0.2 parts of sodium sulfonated dioctyl succinate interfacial tension regulator, stir and mix well to make a coating solution, and use a wire rod to coat 12g / m2 on the paper base and PET film respectively. 2 The pressure-sensitive film was then dried to obtain the pressure-sensitive film. The pressure-sensitive film was printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: the color density was 0.68, and the color lines printed at 200°C did not fall off.

[0072] Example 6

[0073] In the stirring kettle, 100 parts of treated clay, 2 parts of metal zinc modified phenolic resin, 3 parts of 3,5-dibenzyl salicylic acid zinc, 8 parts of starch, 6 parts of styrene-butadiene latex, 3 parts of PVOH, 2 parts of rheology modifier sodium carboxymethyl cellulose, and 0.2 parts of sodium salt of dioctyl sulfonate succinate interfacial tension regulator were added in sequence, and the mixture was stirred and mixed to form a coating liquid. 10 g / m2 of the coating liquid was applied on the paper base and PET film respectively using a wire rod. 2 The pressure-sensitive films were then dried to obtain the pressure-sensitive films. The pressure-sensitive films were printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: the color density was 0.77, and the color lines printed at 200°C did not fall off.

[0074] Example 7

[0075] Add 100 parts of treated clay, 5 parts of aluminum chloride, and SO 4 2ˉ / TiO 2 5 parts of solid super acid, 5 parts of metal zinc modified phenolic resin, 10 parts of starch, 5 parts of gelatin, 6 parts of styrene-butadiene latex, 3 parts of PVOH, 2 parts of sodium carboxymethyl cellulose, 0.3 parts of Tween-20 interfacial tension regulator, stir and mix well to make a coating liquid, and use a wire rod to coat 15g / m2 on the paper base and PET film respectively.2 The pressure-sensitive film was then dried to obtain the pressure-sensitive film. The pressure-sensitive film was printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: the color density was 0.78, and the color lines printed at 200°C did not fall off.

[0076] Example 8

[0077] Add 100 parts of treated clay, 2 parts of aluminum chloride, 3 parts of zinc sulfate, and SO 4 2ˉ / TiO 2 5 parts of solid super acid, 2 parts of metal zinc modified phenolic resin, 3 parts of 3,5-dibenzyl salicylic acid zinc, 10 parts of starch, 5 parts of gelatin, 6 parts of styrene-butadiene latex, 3 parts of PVOH, 2 parts of sodium carboxymethyl cellulose, 0.3 parts of Tween-20 interfacial tension regulator, stir and mix well to make a coating liquid, and use a wire rod to coat 15g / m2 on the paper base and PET film respectively. 2 The pressure-sensitive film was then dried to obtain the pressure-sensitive film. The pressure-sensitive film was printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: the color density was 0.78, and the color lines printed at 200°C did not fall off.

[0078] Comparative Example 1

[0079] 100 parts of calcium carbonate powder, 15 parts of 3,5-dibenzyl salicylate zinc, 9 parts of starch, 5 parts of styrene-butadiene latex, 3 parts of PVOH, 2 parts of rheology modifier sodium carboxymethyl cellulose, and 0.3 parts of Tween-20 interfacial tension regulator were added into the stirring kettle in sequence, and the mixture was stirred and mixed to form a coating liquid. 10 g / m2 of the coating liquid was applied on the paper base and PET film respectively using a wire rod. 2 , and then dried separately to obtain pressure-sensitive films. The obtained pressure-sensitive films were printed with different dye precursor films coated with electron-donating properties at high and low temperatures to obtain test data: color density 0.79, pressure-sensitive color traces as shown Figure 2 As shown; 200℃ printing color lines fall off, such as Figure 4 shown.

[0080] Comparative Example 2

[0081] Add 100 parts of treated clay, 9 parts of starch, 6 parts of styrene-butadiene latex, 3 parts of PVOH, 1 part of sodium carboxymethyl cellulose, and 0.3 parts of Tween-20 interfacial tension regulator into the stirring kettle in sequence, stir and mix well to make a coating liquid, and use a wire rod to coat 15g / m2 on the paper base and PET film respectively. 2 , and then dried in an oven at 98°C to obtain a pressure-sensitive film. The obtained pressure-sensitive film and different dye precursor films coated with electron-donating properties were printed at high and low temperatures to obtain test data: the color density at 23°C was 0.46, such as Figure 1 shown.

[0082] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A pressure-sensitive film color-developing coating, characterized in that: The composition comprises the following components in parts by weight: 100 parts of activated clay Modifier 15 parts 24 parts of adhesive 2.3 parts of additives; The modifier is a mixture of a solid superacid, an organic synthesis acidic compound and a strong acid and weak base salt in a mass ratio of 1:1:1; The solid superacid is SO4 2 ˉ / TiO2 type solid super acid; The SO4 2 The ˉ / TiO2 type solid superacid is prepared by the following preparation method: titanium dioxide is added to 20% sulfuric acid and soaked for 15 hours, then filtered, dried, and then roasted in a muffle furnace at 550°C for 4 hours, and finally crushed and sieved to obtain the product; The organic synthetic acidic compound is a metal zinc modified phenolic resin, or a mixture of a metal zinc modified phenolic resin and 3,5-dibenzyl salicylic acid zinc in a mass ratio of 2:3; the metal zinc modified phenolic resin is purchased from Scanati Corporation of the United States, and the 3,5-dibenzyl salicylic acid zinc is purchased from Nopco Corporation of Japan; The strong acid and weak base salt is aluminum chloride, or a mixture of zinc sulfate and aluminum chloride in a mass ratio of 3:2; The binder is a mixture of starch, gelatin, styrene-butadiene latex and polyvinyl alcohol in a mass ratio of 10:5:6:3; The auxiliary agents are interfacial tension regulators and rheology modifiers; The interfacial tension regulator is Tween-20; The rheology modifier is sodium carboxymethyl cellulose; Application of a pressure-sensitive film color-developing coating, the color-developing coating is coated on a substrate, and the coating amount of the color-developing coating is 10-15g / m 2 , and then dried to obtain a pressure-sensitive film, which was subjected to high and low temperature printing tests: the color density was 0.78, and the color coating was resistant to high temperatures of 200°C.

2. The method for preparing a pressure-sensitive film color-developing coating according to claim 1, characterized in that: The activated clay, modifier, binder and additive are mixed to obtain the target product.

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