JPS61170745A - Image recording material - Google Patents

Abstract

PURPOSE:To form a visible image by an electrochemical means and to provide excellent shelf stability by constituting a recording layer of a colored electrolytically polymerized film and forming a heat sensitive layer of a polymer complex composed of a basic polymer and acidic polymer. CONSTITUTION:This image recording material consists of a conductive substrate, the recording layer provided on the conductive substrate and the heat sensitive layer provided on the recording layer. The recording layer consists of the colored electrolytically polymerized film and the heat sensitive layer is constituted of the polymer complex composed of the basic polymer and acidic polymer. More specifically, the image recording material 10 is constituted by forming the recording layer 2 consisting of the electrolytically polymerized film on at least one surface of the conductive substrate 1 and forming the heat sensitive layer 3 consisting of the polymer complex thereon. A plate-, sheet- or film-like substrate having about 0.03-3mm thickness is used for the conductive substrate 1 and the recording layer 2 is formed to about 0.1-10mum thickness. The heat sensitive layer 3 is generally formed to about 0.1-10mum. The visible image is thus formed by the electrochemical means and the excellent shelf stability is obtd.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an image recording material useful for recording various information using a thermal pattern and forming a visible image. A recording layer with a specific configuration and a heat-sensitive layer with a specific configuration are formed thereon, a latent image is formed in the heat-sensitive layer by a thermal pattern, and the recording layer is developed by electrochemical means using the latent image. An object of the present invention is to provide an image recording material that can be easily converted into a visible image.

(Prior Art) Many methods have been known for recording various types of information using thermal patterns. By providing variable heat sensitive layers and applying a thermal pattern to these heat sensitive layers, a visible change in the heat sensitive layer or a recorded image readable by other readout means is formed. Heat-sensitive materials are often used to form the heat-sensitive layer, and many of these materials are various polymers, pigments, or mixtures thereof.

(Problem to be Solved by the Invention) Heat-sensitive polymers and dyes are often used to form the heat-sensitive layer of image recording materials used in the conventional thermal pattern recording method as described above. When forming a heat-sensitive layer from these materials, there is a problem in that sufficient care must be taken in handling these materials.

That is, to form heat-sensitive layers from materials that are sensitive to thermal patterns, those materials must be heat-resistant before use, and for similar reasons, storage of image-recording materials after formation requires If sufficient precautions are not taken, there is a problem that the material will lose its heat sensitivity and properties before use, making it unusable.

In addition, even with such various precautions, conventional thermal pattern image recording materials have problems with the storage stability of recorded materials after recording, and are not reliable enough in terms of long shelf life. It wasn't something.

Therefore, there is no need to take special precautions during production, a heat-sensitive layer can be easily formed, information can be easily recorded, and the recorded information can be stably stored for a long period of time. The reality is that there is still a strong demand for this.

As a result of intensive research in order to meet the demands of the prior art as described above, the present inventors have discovered that a conductive substrate is used as a support base for an image recording material, a recording layer is formed from a specific material, and a heat-sensitive layer is formed. When a polymer material with a specific composition is used as a constituent material, various information can be easily recorded by a thermal pattern, and the latent image of the recorded information can be used to create a visible image by specific electrochemical means. The present invention was completed based on the finding that a recorded image having excellent storage stability can be obtained by doing so.

(Means for solving the problems) That is, the present invention comprises a conductive substrate, a recording layer provided on the conductive substrate, and a heat-sensitive layer provided on the recording layer,
The image recording material is an image recording material in which the recording layer is made of a colored electropolymerized film, and the heat-sensitive layer is made of a polymer complex of a basic polymer and an acidic polymer.

To explain the present invention in detail, the main features of the present invention are:
The first feature is that a conductive substrate is used as the substrate of the image recording material, and the second feature is that the recording layer is formed of a specific colored polymer9, ts3v**t* ,
ml+RcyyYjdtt, ni@'? cy>, yU
The point is that the I-mer complex is adopted.

The image recording material of the present invention thus formed is then treated with a thermal pattern to form a latent image using a conventional method, and the resulting latent image is easily developed by electrochemical means. be able to.

Therefore, the present invention will be further described in detail focusing on these main features.

The conductive substrate used as the substrate of the image recording material in the present invention may be any material as long as it is conductive, such as metal plates such as gold, platinum, silver, nickel, copper, these metals, or tin oxide. , conductive oxides such as indium oxide, indium-tin oxide, or other conductive materials can be used on any substrate such as a glass plate, various resin films, or sheets on one or both sides.

In the present invention, the recording layer provided on the substrate is formed by electrolytic polymerization. Such electrolytic polymerization is a method in which an electrolytically polymerizable top is added to an electrolytic solution and electrolytic polymerization is performed using a conductive substrate as an anode.

The electrolytic polymerization method used in the present invention includes, for example, [
Applied Physics, Vol. 52, No. 11 (1983) P971~
974, which is known per se, but according to detailed research by the present inventors, such an electrolytic polymerized membrane absorbs heat very well, and the heat-sensitive layer formed on the membrane absorbs heat very well. It has been found that this material is suitable as the recording layer of the image recording material of the present invention because it enhances the heat sensitivity of the material, facilitates thermal changes in the heat-sensitive layer, and can be easily developed electrochemically afterwards. .

That is, when electricity is applied in an electrolytic solution containing a monomer for electrolytic polymerization using the above conductive substrate as an anode, electrolytic polymerization occurs on the surface of the anode, and a colored electrolytic polymer film is formed on the surface. , a recording layer with excellent performance is formed.

Examples of monomers used in such electrolytic polymerization include monomers such as pyrrole, thiophene, furan, selenophene, tellurophene, indole, azulene, aniline, chenothiophene, pyrrolopyrrole, and diacetylene. is about o in the electrolyte,
It is preferable to use it at a concentration of about oot to IM.

In addition, as the cathode which is the opposite electrode to the above anode, gold, platinum,
Any electrode material such as nickel may be used, and these cathodes may have any shape.

As the electrolyte, any conventionally known electrolyte such as water, acetonitrile, ethanol, dimethylformamide, dioxane, dichloroethane, and tetrahydrofuran can be used.
r, K1. LiC Bun O, LiBF4. Any electrolyte can be used, such as tetra-n-butylammonium cymperchlorate, tetra-n-butylammonium perfluoroporate, tetramethylammonium chloride, Na2S%, etc., and these electrolytes have a concentration of about 0. It is preferable to dissolve it at a concentration of about O1 to IM.

The electrolytic polymerization conditions vary depending on the type of hexamer used, the type and shape of the electrode, the type and concentration of the electrolytic solution and electrolyte, and the size of the recording surface of the conductive substrate used in the present invention. Generally, by applying a DC voltage of 1-10V, approximately O0l~lo is applied on the conductive substrate in several seconds to several minutes.
A colored electropolymerized film, ie, a recording layer, having a film thickness of gm is formed.

The electropolymerized membrane formed as described above is generally strongly colored from brown to black depending on the type of electrolyte, but if the degree of coloring is small, anionic dyes such as acid dyes and direct dyes may be present in the electrolyte. By dissolving an appropriate amount of a pigment such as a dye having a functional group.

You can change the hue of the coloring or increase the density.

Furthermore, it goes without saying that such coloring with a dye may be performed after the film is formed.

Furthermore, the polymer complex used to form the heat-sensitive layer on the recording layer on the substrate is composed of a basic polymer and an acidic polymer, and for example,
5-42744, which is already known per se, basic poly, -yo, □yo, 9e, 1 engineering. . ,. 6. lN-vinylpyrrolidone, N-vinyl-3-
Methylpyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-3,3,5-trimethylpyrrolidone, N
-vinyl-3-benzylpyrrolidone, N-vinylpiperidone, N-vinyl-4-methylpiperidone, N-vinyl-caprolactam, N-vinylcapryllactam, N
- Homopolymers of vinyl-3-morpholine, N-vinylthiopyrrolidone, N-vinyl-2-pyridone, etc., or random copolymers, block copolymers, graft copolymers, etc. with other common monomers; N-vinyl-2-oxacylidone, N-vinyl-5-methyl-2-oxazolidone, N-vinyl-5-ethyl-
2-oxacylidone, N-vinyl-4-methyl-2-oxacylidone, N-vinyl-2-thioxazolidone,
Homopolymers such as N-vinyl-2-mercaptobenzothiazole or random copolymers with other common monomers.

Block copolymers, graft copolymers, etc.; N-vinylimidazole, N-vinyl-2-methylimidazole, N
- Homopolymers such as vinyl-4-methylimidazole or random copolymers, block copolymers, graft copolymers, etc. with other common monomers; Homopolymers such as 2- or 4-vinylpyridine Or random copolymers, block copolymers, graft copolymers, etc. with other common heptamers, etc. Other copolymerizable monomers that may be used in the above include methacrylate, acrylate, Particularly useful in the present invention are N-
Vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylmorpholine, N-vinyl-
These include homopolymers and copolymers of 2-oxacylidone and N-vinyl-5-methyl-2-oxazolidone. In the case of a copolymer, 50 mol% of the above-mentioned nitrogen-containing polymer is used.
It is preferable that the above is included.

Further, examples of acidic polymers capable of forming a polymer complex with the above-mentioned basic polymers include the following.

Polyesters with terminal carboxyl groups obtained by reacting polycarboxylic acids such as citric acid, tartaric acid, and phthalic acid with polyhydric alcohols such as ethylene glycol, 1.4-butanediol, and diethylene glycol in excess of acid; various polycarboxylic acids Acidic cellulose derivative modified with (
(See Japanese Patent Publication No. 35-5093): Homopolymers such as vinyl ether ester monomers of polyhydric carboxylic acids, random copolymers, block copolymers, graft copolymers, etc. with other common monomers (see Japanese Patent Publication No. 35-5093) 35-8495
Homopolymers of monomers such as niacrylic acid or methacrylic acid, or random copolymers with other common heptamers,
Block copolymers, graft copolymers, etc.; homopolymers of α,β-unsaturated vinyl humers such as maleic anhydride and itaconic acid, or random copolymers and block copolymers with other common monomers; Graft copolymers, etc. Other monopolymers containing sulfonic acid or phenol groups, or random copolymers with other common monomers, block copolymers, graft copolymers, etc. Other carboxyl groups or acidic modified products of various polymers with compounds containing sulfonic acid groups or phenol groups: Although any of the above acidic polymers can be used, particularly preferred in the present invention are α,β-unsaturated acids alone. These include polymers, random copolymers, block copolymers, and graft copolymers, and particularly preferred is a copolymer of alkyl vinyl ether and maleic anhydride.

The present inventor has been conducting various research on mixtures of basic polymers and acidic polymers as described above, and found that
By mixing these polymers in a solution, - will have some interaction with each other, and
A polymer complex different from either polymer is formed, and if both polymers are mixed in a relatively good solvent, the polymer complex will precipitate, and if mixed in a relatively good solvent, a significant increase in viscosity will occur, and the use of It has been discovered that this polymer has properties different from that of a mere mixture of both polymers.

Therefore, the polymer complex used in the present invention means a polymer complex consisting of the above-mentioned polymers. In the present invention, it is preferable to use both polymers in such a manner that their basicity and acidity are approximately the same. The mixing ratio can be determined by calculating the basicity and acidity of both polymers, and determining the mixing ratio of both polymers accordingly. Furthermore, a polymer complex formed by mixing in an appropriate ratio becomes a polymer complex that cannot be strongly dyed by either acidic dyes or basic dyes. Therefore, the mixing ratio of both polymers can be determined using these factors.

The polymer complexes obtained as described above generally do not dissolve in relatively good solvents such as water, alcohol, esters, hydrocarbons, etc., so both polymers are dissolved in these poor solvents and recycled. By mixing the solutions, the polymer complexes used in the invention can be isolated. Also, dimethylformamide,
By mixing in a relatively good solvent such as dimethylacetamide, dimethylsulfoxide, etc., a solution of the polymer complex can be obtained. Therefore, in forming a heat-sensitive layer on a conductive substrate as described above using a polymer complex as described above, (1) prepare a solution of each of the two polymers;
(2) A method of applying one of the solutions onto the recording layer on the substrate, and then applying a predetermined amount of the other polymer solution thereon to form a polymer complex on the recording layer; A method can be used in which a solution of the polymer complex is prepared using a good solvent and the solution is applied onto the recording layer.

The image recording material of the present invention is formed using the above materials, but in the present invention, in addition to the above materials, for example, a thermoplastic polymer other than the above may be used in combination with the above polymer complex. Small amounts of colorants may be included to enhance their film-forming ability and to give their films a light color.

Next, the present invention will be described in more detail with reference to the accompanying drawings that schematically illustrate the structure of the image recording material of the present invention.

FIG. 1 schematically shows the structure of the image recording material 1O of the present invention with its cross-sectional shape, where 1 indicates the conductive substrate as described above, and 2 indicates the recording layer made of an electrolytic polymer film. 3 indicates a heat-sensitive layer made of a polymer complex.

FIG. 2 is a schematic cross-sectional view of an image recording material of another example.

As shown in FIGS. 1 and 2, the image recording material 10 of the present invention includes:
A recording layer 2 made of an electrolytically polymerized film is formed on at least one surface of a conductive substrate 1, and a thermosensitive layer 3 made of the above-mentioned polymer complex is further formed thereon. As shown in FIG. 2, a recording layer 2 and a heat-sensitive layer 3 are provided on both sides of a conductive substrate 1.
If formed, the image recording material 10 will have the recording layer 2 and the heat-sensitive layer 3 on both sides. When the recording layer 2 and the heat-sensitive layer 3 are formed only on one surface, it is preferable to apply an insulating film (not shown) of an arbitrary thickness to the other surface. This is not necessary when the substrate is conductive on one side, such as ITO-deposited glass or aluminum-deposited film.

The conductive substrate 1 used can technically have any thickness and any shape, but generally has a thickness of about 0.0
It is preferably in the form of a plate, sheet, or film with a thickness of 3 to 3 cm, and the shape may be any shape, such as a tape shape, depending on the intended use of the image recording material obtained.
The recording layer 2 may have the same shape as the substrate 1 or may have a smaller area. , 1-10. .

Yes - is preferable. The heat sensitive layer 3 is made of 1 as described above.
Although it may be formed by a liquid method or a two-liquid method, it is generally preferable that the thickness is about 0.11-101L.

The present inventor discovered that although the image recording material formed as described above has a substrate 1 and a recording layer 2 that are electrically conductive,
It has been found that the material becomes a poor conductor as a whole and loses good electrical conductivity. This could naturally be predicted since the two types of polymers constituting the polymer complex forming the heat-sensitive layer 3 are mutually neutralized, but further detailed research by the present inventors revealed that this could be expected. found that when these heat-sensitive layers are exposed to a thermal pattern with greater energy than the surrounding atmosphere, only that portion of the heat-sensitive layer becomes conductive again, that is, a latent image consisting of conductive regions is formed. This is what I did. Moreover, such latent images retained their electrical conductivity for several minutes to several days after application of the thermal pattern was discontinued, and then returned to their original insulating properties.

As for the method of recording information and forming a latent image by exposing the above-mentioned image recording material to a thermal pattern, any conventionally known method can be used.For example, as schematically shown in FIG. For example, a thermal stylus, a thermal type, a thermal printing head, a mechanical method in which the heat sensitive layer of an image recording material is locally and selectively heated by scanning with thermal energy 4 such as a laser beam or an electron beam, and a radiation absorbing method. Any other method may be used, such as a radiant heating method in which an original document having a character pattern (not shown) and an image recording material are placed one on top of the other in a heat conductive position, and intense radiation is applied using an incandescent tungsten lamp or the like.

As described above, a desired latent image is formed in the heat-sensitive layer of the image recording material of the present invention, but the image recording material of the present invention can be developed into a visible image as follows: Such a developing method is also an important feature of the present invention.

A method for developing the latent image formed as described above will be specifically explained with reference to the accompanying drawings. FIG. 4 schematically shows a method for developing the latent image 5 formed on the image recording material of the present invention, and FIG. 5 schematically shows a cross section of the developed image recording material 10. This is what is shown.

As shown in FIGS. 4 and 5, one preferred method for developing is to immerse the image recording material 10 on which these latent images have been formed as an anode in an electrolytic solution 6, and then energize it. Due to such energization, only the latent image area becomes conductive, and as a result, the electrolytic polymer film, which is the recording layer corresponding to the latent image area, becomes colorless due to electrochemical action. Although the mechanism of this colorlessness is not clear, it is thought that the conjugated system in the electrolytically polymerized film, which is the recording layer, is oxidized and cleaved by anodic oxidation during energization, resulting in colorlessness. Furthermore, when a dye anion is present in the polymer film, it is thought that the dye is similarly oxidized and decomposed to become colorless. In this way, a negative pattern with high contrast is formed. Incidentally, if a thermal pattern is applied to a non-image area and the image recording material is developed in the same manner, a positive pattern will naturally be formed.

In addition, the electrolytic solution 6 and cathode 8 in the above development process are as follows:
The electrolytic solution and cathode may be the same as those in the electrolytic polymerization described above, and the developing conditions may also be the same.

As explained in detail above, the image recording material of the present invention has a recording layer made of an electrolytic polymer film formed on a conductive substrate, and a specific heat-sensitive polymer complex formed on the recording layer.
The recording layer and the heat-sensitive layer that have been formed do not lose their heat sensitivity at all even if they are left in a normal atmosphere, and the recording layer and the heat-sensitive layer In forming the layer, there is no need to pay special attention under normal atmosphere, so the production is industrially advantageous, and the formed latent image can be easily processed by electrolytic treatment. Developed into a high-contrast image. In addition, after development, the area where the latent image was and the other areas of the heat-sensitive layer return to the same state as the stable polymer complex before recording over time, and as a whole, depending on the ambient conditions, The storage stability of recorded information is extremely high.
l゛Excellent. Next, the present invention will be explained in more detail with reference to Examples.

Note that "%" or "%" in the middle of the sentence is based on weight.

Example 1 Virol 0. IM and 0.1 M of sodium p-toluenesulfonate were dissolved in water to prepare an electrolytic polymerization solution. An ITO glass plate with a resistance of 20Ω and a size of 10×1Oc was placed as an anode, and a nickel plate was used as a cathode, and electrolysis was performed at a DC voltage of 3V for 50 seconds to form a greenish-brown conductive polypyrrole film (thickness approximately 1JLm). formed on the anode.

Next, the following polymer solution was applied to a dry film thickness of 3 ILm by a spinner coating method and dried to form a heat-sensitive layer, thereby obtaining an image recording material of the present invention.

Polyvinylpyrrolidone (K=90) 5 parts Polymethyl vinyl ether/maleic anhydride-monobutyl nystyl copolymer (Gantretz ES-425, 50% ethanol solution, manufactured by GAF) 10 parts Ethanol 100 parts Dimethylformamide 100 parts Then, From the surface of the heat-sensitive layer of the image recording material, argon laser (wavelength 514 nm)
, power 10 mW) was irradiated to 1 ILSeC to perform bit recording.

Next, the above image recording material was connected to the anode and the nickel plate was connected to the cathode, and when a DC voltage of 3 V was applied for 3 seconds in a 1% aqueous solution of sodium P-toluenesulfonate, only the area irradiated with the laser beam was selected. The color changed from brown to colorless and transparent, and a negative pattern was formed. This image can be read out as a signal with a large transmitted light intensity ratio.

Example 2 An image recording material prepared in exactly the same manner as in Example 1 was exposed to non-image areas with argon laser light in the same manner as in Example 1, and then treated in a 0.1 molar aqueous solution of P-) sodium sulfonate. When the above image recording material was connected to the anode and the nickel plate was connected to the cathode and a DC voltage of 4 V was applied for 10 seconds,
The unexposed areas were brown and the exposed areas were colorless and white, forming a positive pattern. The obtained images had sufficient contrast and were useful for slides, masks, optical discs, etc.

[Brief explanation of the drawing]

1 and 2 schematically show the structure of the image recording material of the present invention, FIG. 3 schematically shows the thermal pattern treatment in the present invention, and FIG. 4 schematically shows the developing method in the present invention. and FIG. 5 schematically shows the developed image recording material. l... Conductive base material 2... Recording layer 3... Heat sensitive layer 4... Thermal energy 5... Latent image 6...・・・・・・
Electrolyte 7... Image 8...
On the cathode J... Image recording material Figure 1 Figure 4

Claims (1)

[Claims] It consists of a conductive substrate, a recording layer provided on the conductive substrate, and a heat sensitive layer provided on the recording layer, the recording layer being made of a colored electropolymerized film, and the heat sensitive layer being made of a basic polymer and an acidic polymer. An image recording material consisting of a polymer complex of