JPH01115679A - Image forming method - Google Patents

Abstract

PURPOSE:To form a clear image, by bringing a solution of an electron-donative leuco dye in an organic solvent into contact with a color developer layer provided by applying onto a base a color developing emulsion comprising a color developer in polymeric aqueous emulsion particles. CONSTITUTION:An image is formed by bringing a solution of an electron- donative leuco dye in an organic solvent into contact with a color developer layer provided by applying to a base a color developing emulsion comprising a color developer in polymeric aqueous emulsion particles. The color developing emulsion is applied to the base, and is dried, thereby forming a dry film adhered to the surface of the base. The solution of the leuco dye in the organic solvent may be brought into contact with the color developer layer by, for example, a method wherein an upper-sheet paper of a pressure sensitive recording paper is opposed to the color developer layer, and microcapsules are broken to bring the leuco dye solution contained in the microcapsules into contact with the color developer layer, a method wherein the leuco dye solution is brought into contact with the color developer layer by a recorder such as an ink jet recorder, or a method wherein the leuco dye solution is directly brought into contact with the color developer layer by a paintbrush or the like.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a novel method for forming an image by bringing an organic solvent solution of an electron donating leuco dye into contact with a color developing layer formed from an emulsion having a color developing function. The present invention relates to an image forming method.

(Prior Art) As a recording system that utilizes the reaction between an electron-donating leuco dye and an electron-accepting color developer, pressure-sensitive recording paper has been put to practical use. This usually consists of an upper paper whose back side is coated with microcapsules containing an electron-donating leuco dye and an organic solvent, and a lower paper whose front side is coated with an electron-accepting developer. The microcapsules are destroyed by pressure printing from above with a ballpoint pen or typewriter, and the colorless leuco dye solution in the microcapsules transfers to the underlying paper and reacts with the color developer to form a colored recorded image. It is something.

Commonly used electron-accepting color developers include acid clay minerals such as acid clay and activated clay, acidic polymers such as p-phenylphenol resin, and aromatic carboxylic acids and zinc aromatic carboxylic acids such as salicylic acid derivatives. These include metal salts such as salt. These electron-accepting color developers are solid fine powders that are adhesively fixed to paper surfaces using various binders, and are described in detail in, for example, Japanese Patent Laid-Open No. 127486/1986.

(Problems to be Solved by the Invention) Conventionally used color developers are solid fine powders, and are usually used in a state of being dispersed in water in the presence of a dispersant. When this is applied onto a substrate and dried, it returns to a fine powder state since it originally has solid properties, and forms a cloudy dry film. Furthermore, if various binders are not used in combination, the powder will not adhere to the surface of the substrate and will fall off. or,
Even when various binders are used in combination to maintain adhesion, the adhesion is good, but the film remains cloudy, and if characters, images, etc. are printed or drawn on the substrate in advance, the film may become cloudy. There is a drawback that it becomes difficult to distinguish the characters and images below.

As a result of intensive research to solve the above problems, the present invention has been completed.

(Means for Solving the Problems) According to the present invention, an emulsion having a color developing function in which a color developer is contained in polymer aqueous emulsion particles is applied to a color developing layer formed by applying an emulsion having a color developing function on a substrate. A novel image forming method is provided, which is characterized by contacting an organic solvent solution of a donating leuco dye. Phenol derivatives having a radically polymerizable group and having color developing ability for leuco dyes, such as p-vinylphenol, m-iso:l-robenylphenol, 2-hydroxy-4-vinylbenzoic acid, etc. Copolymerizable monomers, such as 1,3-butadiene, styrene, methyl methacrylate, butyl acrylate, methacrylic acid, etc., are used so that the resulting copolymer has sufficient adhesion to a substrate such as paper. A method of emulsion copolymerization with a polymer mixture, and polyvalent metal salts of aromatic carboxylic acids disclosed in Japanese Patent Application No. 61-128331, such as 6.5-di-t-butylsalicylic acid, 3.5-di α, α - Obtained by a method in which a polyvalent metal salt such as calcium, zinc, or aluminum, such as dimethylbenzyl salicylic acid, is incorporated into emulsion particles of an aqueous polymer emulsion.In the latter case,
The color developer is not limited to the above-mentioned compounds, but can be used for leuco dyes such as aromatic carboxylic acids, phenols, and phenol-formaldehyde resins disclosed in Japanese Patent Publication No. 6-3T5953. Any organic color developer having color developing ability can be used.

When these emulsions having a color developing function are applied to a substrate and dried, they form a dry film that adheres to the surface of the substrate.

This dry film becomes a color developing layer that has color developing ability for leuco dyes.

As the substrate in the present invention, any substrate can be used as long as it can be coated with the emulsion having a color developing function of the present invention. For example, polyester, diacetate, triacetate, acrylic polymer, polycarbonate, polyvinyl chloride, polyimide, cellophane, film such as celluloid, paper such as paper, coated paper, synthetic paper, polyamide, acrylic polymer, etc. Examples include nonwoven fabrics or cloths made of fibers such as viscose rayon, cellulose ester, polyester, cotton, silk, wool, and sud, metal films or plates made of iron, aluminum, etc.

To form a color developing layer on such a substrate, coating, printing,
Transfer or other known methods may be used.

For example, an emulsion with a color developing function is sprayed onto the substrate surface, or coated using a wire bar, air knife coater, or blade coater, and heated at 25 to 200°C.
A color developing layer is formed by drying with .

Examples of the electron-donating leuco dye used in the present invention include the trifluoride disclosed in JP-A-59-T74385 VC;
Examples include arylmethane-based, diphenylmethane-based, xanthine-based, thiazine-based, and spiropyran-based compounds. To give some examples of these, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (i.e., crystal violet lactone) is a triarylmethane-based compound; Examples of the compounds include 4,4'-bisdimethylaminobenzhydrin benzyl ether and N-halophenyl-leucoauramine, and examples of the xanthine compounds include rhodamine-B-anilinolactam and 2-dibenzylamino-6- Diethylaminolluorane, 2-anilino-6
-Dinithylaminofluorane, 2-phenyl-6-dinithylaminofluorane, etc.; as thiazine compounds, benzoylleucomethylene blue, p-nitrobenzylleucomethylene blue, etc.; as spiropyran compounds, 6-metelose Pyrosinaphtobilan, 3.6
'-Cyclolosespirodinaphthopyran, 6-methylnaphtho-(3-methoxy-benzo)-spiropyran, and the like. These may be used alone or in combination.

In the present invention, the leuco dye is used after being dissolved in an organic solvent, but any organic solvent can be used as long as it dissolves the leuco dye. For example, alcohols such as methanol, ethanol, propanol, and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as dimethyl needle, diethyl ether, and tetrahydrofuran, and esters such as methyl acetate, ethyl acetate, and propyl acetate. , aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, and trichloroethane. Organic solvents can be used alone or in combination.

Image formation in the present invention is achieved by bringing the color developing layer formed on the substrate described above into contact with a leuco dye solution.

The color developing layer and the organic solvent solution of the leuco dye can be brought into contact by, for example, a method in which the upper paper of pressure-sensitive recording paper is placed facing each other and the microcapsules are destroyed by pressure, and the leuco dye solution contained therein is brought into contact with the microcapsules, or an inkjet method. Examples include, but are not limited to, a method of bringing the leuco dye solution into contact with the dye using a recording device such as a leuco dye solution, and a method of bringing the leuco dye solution into direct contact with the dye using a paintbrush or the like.

(Effects of the Invention) Thus, in the present invention, by bringing an organic solvent solution of an electron-donating leuco dye into contact with a color developing layer formed from an emulsion having a color developing function on a substrate, the color developing layer develops a color. A reaction occurs and a clear image is formed. or,
This color developing layer allows for clear VC observation of underlying characters, images, etc. even if characters, images, etc. are printed on the substrate in advance. Furthermore, by changing the leuco dye, the color of the colored portion can be changed freely, and color recording is also possible.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 ■ Preparation volume of emulsion with color developer function: approx. 1-e
In a pressure-resistant glass bottle, 600 y of deionized water, toy sodium lauryl sulfate, 0.52 y of sodium bicarbonate,
After adding 0.82 sodium persulfate and degassing, 1.3-
Butadiene 30v1 Styrene 15y1 Methyl methacrylate 552, Tert-dodecyl mercaptan 0.
5? A solution of 60 g of 3,5-di-tertiaryptersalicylic acid zinc salt in 30 g of ethyl acetate was charged.

After degassing, the container was sealed and the reaction was carried out at 60'Q for 15 hours with rotational mixing. The conversion rate reached over 99%.

The obtained emulsion having a color developing function was cooled with water, unreacted monomers and solvent were removed, and then the 1)H of the latex was adjusted to 7 and the solid content concentration to 45% with NaOH.

■ Preparation of an organic solvent solution of leuco dye
2 to obtain a leuco dye solution.

■ Coating and drying on the substrate ■ Emulsicon with color developing function was used on high-quality paper with a basis weight of 60 Y/m, and the dry coating amount was 277.
711' and dried at 80°C for 1 minute.

(2) The emulsion with color developing function (2) was sprayed onto a commercially available cotton cloth using a simple sprayer so that the dry coating amount was 11/〃-, and the mixture was dried at 80°C for 1 minute.

(2) Image formation The leuco dye solution prepared in (2) was applied with a paintbrush to the surface of the coating prepared in (2) and (2). After application, all contact areas immediately took on a clear w color.

While the solvent remained, the colored surface remained sticky, but 8
By drying at 0°C for 1 minute, the solvent was completely removed and a solid image was obtained.

Example 2 In Example 1, 2-hydroxy-4-vinyl- was used instead of 6,5-di-tert-butylsalicylic acid zinc salt.
6-tert-butylbenzoic acid zinc salt 302 was used. When evaluated in the same manner as ■, ■, and ■ in Example 1, all exhibited a clear blue color.

Comparative Example 1 ■ Preparation of aqueous polymer emulsion An aqueous polymer emulsion was prepared in the same manner as in Example 1 (■) except for the zinc salt of 3,5-di-tert-butylsalicylic acid 〇■ Mixing with color developer■ The aqueous polymer emulsion and 3,5-di-tert-butylsalicylic acid zinc salt were mixed in the same ratio as in Example 1 (2). However, 6.5-di-tert-butylsalicylic acid zinc salt floated on the water surface, making it impossible to form a mixed emulsion. .5-di-tert-butylsalicylic acid zinc salt 901 was placed in a mixer and strongly stirred for 3 minutes to obtain a dispersion. This dispersion 53.3 F and 113.7 F of the aqueous polymer emulsion (solid content concentration: 45 wt. i%) were mixed.

■ Coating and drying on the substrate In the same manner as in Example 1, apply to high-quality paper and cotton cloth using a wire bar and a simple sprayer, respectively, and dry at 80°C.
and dried for 1 minute.

(2) As in (2) of Image Formation Example 1, a leuco dye solution was applied to the surface of the coated material using a paintbrush. After application, the contact area gradually turned blue, but the color was lighter than in Example 1. The colored material was heated at 80°C for 1
After drying for a minute, the reflectance of the colored portion of the high-quality paper was measured through a blue filter of a Hunter whiteness meter (manufactured by Toyo Seiki), and the Jd was 35.6% in Example 1 and 37.0% in Example 2. In the comparative example, it was 62.1%, and the color density of the example was high.

Example 3 The emulsion having a color developing function of Example 1 was applied to the surface of an already printed printed matter so that the dry coating amount was 217 m'', and the emulsion was dried at 80° C. for 1 minute.

The dried film was transparent, and the printed surface underneath was well observed. Comparative Example 2 Similarly to Example 3, the dispersion of Comparative Example 1 (■) was applied to the printed surface, and the dried film became cloudy. The printed surface under the cage was difficult to observe.

As can be seen from the above examples and comparative examples, an image is formed by bringing an organic solvent solution of an electron donating leuco dye into contact with a color developing layer formed from an emulsion having a color developing function on a substrate of the present invention. It can be seen that the recording system is a new image forming method.

Patent applicant: Zeon Corporation

Claims (1)

[Claims] An image characterized in that an organic solvent solution of an electron-donating leuco dye is brought into contact with a color developing layer formed by coating a color developing function-enabled emulsion in which a color developer is contained in polymer aqueous emulsion particles on a substrate. Formation method.